Preliminary analysis of alternative fuel cycles for proliferation evaluation
Energy Technology Data Exchange (ETDEWEB)
Steindler, M. J.; Ripfel, H. C.F.; Rainey, R. H.
1977-01-01
The ERDA Division of Nuclear Research and Applications proposed 67 nuclear fuel cycles for assessment as to their nonproliferation potential. The object of the assessment was to determine which fuel cycles pose inherently low risk for nuclear weapon proliferation while retaining the major benefits of nuclear energy. This report is a preliminary analysis of these fuel cycles to develop the fuel-recycle data that will complement reactor data, environmental data, and political considerations, which must be included in the overall evaluation. This report presents the preliminary evaluations from ANL, HEDL, ORNL, and SRL and is the basis for a continuing in-depth study. (DLC)
Fuel cycle parameters for strategy studies
International Nuclear Information System (INIS)
Archinoff, G.H.
1979-05-01
This report summarizes seven fuel cycle parameters (efficiency, specific power, burnup, equilibrium net fissile feed, equilibrium net fissile surplus, first charge fissile content, and whether or not fuel reprocessing is required) to be used in long-term strategy analyses of fuel cycles based on natural UO 2 , low enriched uranium, mixed oxides, plutonium topped thorium, uranium topped thorium, and the fast breeder oxide cycle. (LL)
International Nuclear Information System (INIS)
Hu, Dongshuai; Li, Saili; Zheng, Ya; Wang, Jiangfeng; Dai, Yiping
2015-01-01
Highlights: • A method for preliminary design and performance prediction is established. • Preliminary data of radial inflow turbine and plate heat exchanger are obtained. • Off-design performance curves of critical components are researched. • Performance maps in sliding pressure operation are illustrated. - Abstract: Geothermal fluid of 90 °C and 10 kg/s can be exploited together with oil in Huabei Oilfield of China. Organic Rankine Cycle is regarded as a reasonable method to utilize these geothermal sources. This study conducts a detailed design and off-design performance analysis based on the preliminary design of turbines and heat exchangers. The radial inflow turbine and plate heat exchanger are selected in this paper. Sliding pressure operation is applied in the simulation and three parameters are considered: geothermal fluid mass flow rate, geothermal fluid temperature and condensing pressure. The results indicate that in all considered conditions the designed radial inflow turbine has smooth off-design performance and no choke or supersonic flow are found at the nozzle and rotor exit. The lager geothermal fluid mass flow rate, the higher geothermal fluid temperature and the lower condensing pressure contribute to the increase of cycle efficiency and net power. Performance maps are illustrated to make system meet different load requirements especially when the geothermal fluid temperature and condensing pressure deviate from the design condition. This model can be used to provide basic data for future detailed design, and predict off-design performance in the initial design phase
Life cycle analysis in preliminary design stages
Agudelo , Lina-Maria; Mejía-Gutiérrez , Ricardo; Nadeau , Jean-Pierre; PAILHES , Jérôme
2014-01-01
International audience; In a design process the product is decomposed into systems along the disciplinary lines. Each stage has its own goals and constraints that must be satisfied and has control over a subset of design variables that describe the overall system. When using different tools to initiate a product life cycle, including the environment and impacts, its noticeable that there is a gap in tools that linked the stages of preliminary design and the stages of materialization. Differen...
Preliminary tension effect on low-cycle fatigue of 40Kh13 steel in gaseous hydrogen
International Nuclear Information System (INIS)
Romaniv, A.N.
1984-01-01
Comparative bending tests of specimens deformed by tension at 65, 18 and 30% in hydrogen and vacuum were accomplished to reveal the effect of preliminary tension on low-cycle fatigue strength of 40Kh13 martensitic steel. It was found that small amounts of preliminary strains induced a considerable decrease in low-cycle durability in vacuum and hydrogen which was connected with developing defects arising at the early stages of plastic deformation. A rather high degree of preliminary tension promoted steel homogenization, hydrogen embrittlement decrease and service behaviour improvement
Development and preliminary analyses of material balance evaluation model in nuclear fuel cycle
International Nuclear Information System (INIS)
Matsumura, Tetsuo
1994-01-01
Material balance evaluation model in nuclear fuel cycle has been developed using ORIGEN-2 code as basic engine. This model has feature of: It can treat more than 1000 nuclides including minor actinides and fission products. It has flexibility of modeling and graph output using a engineering work station. I made preliminary calculation of LWR fuel high burnup effect (reloading fuel average burnup of 60 GWd/t) on nuclear fuel cycle. The preliminary calculation shows LWR fuel high burnup has much effect on Japanese Pu balance problem. (author)
Identification of low cycle fatigue parameters
Directory of Open Access Journals (Sweden)
Balda M.
2009-12-01
Full Text Available The article describes a new approach to the processing of experimental data coming from low-cycle fatigue (LCF tests. The data may be either tables from the standard tests, or a time series of loading processes and corresponding numbers of cycles to damage. A new method and a program for the evaluation of material parameters governing the material behavior under a low cycle loading have been developed. They exploit a minimization procedure for an appropriate criterion function based on differences of measured and evaluated damages.
Preliminary neutronic design of high burnup OTTO cycle pebble bed reactor
International Nuclear Information System (INIS)
Setiadipura, T.; Zuhair; Irwanto, D.
2015-01-01
The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM) loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble. (author)
Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor
Directory of Open Access Journals (Sweden)
T. Setiadipura
2015-04-01
Full Text Available The pebble bed type High Temperature Gas-cooled Reactor (HTGR is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble
Oyster Creek cycle 10 nodal model parameter optimization study using PSMS
International Nuclear Information System (INIS)
Dougher, J.D.
1987-01-01
The power shape monitoring system (PSMS) is an on-line core monitoring system that uses a three-dimensional nodal code (NODE-B) to perform nodal power calculations and compute thermal margins. The PSMS contains a parameter optimization function that improves the ability of NODE-B to accurately monitor core power distributions. This functions iterates on the model normalization parameters (albedos and mixing factors) to obtain the best agreement between predicted and measured traversing in-core probe (TIP) reading on a statepoint-by-statepoint basis. Following several statepoint optimization runs, an average set of optimized normalization parameters can be determined and can be implemented into the current or subsequent cycle core model for on-line core monitoring. A statistical analysis of 19 high-power steady-state state-points throughout Oyster Creek cycle 10 operation has shown a consistently poor virgin model performance. The normalization parameters used in the cycle 10 NODE-B model were based on a cycle 8 study, which evaluated only Exxon fuel types. The introduction of General Electric (GE) fuel into cycle 10 (172 assemblies) was a significant fuel/core design change that could have altered the optimum set of normalization parameters. Based on the need to evaluate a potential change in the model normalization parameters for cycle 11 and in an attempt to account for the poor cycle 10 model performance, a parameter optimization study was performed
Preliminary study for a nuclear multi-cycle reload optimization system
International Nuclear Information System (INIS)
Baptista, Rafael Pereira; Lima, Alan Miranda M. de; Medeiros, Jose Antonio Carlos Canedo; Schirru, Roberto
2007-01-01
Fuel assemblies in a reactor are discharged normally after several fuel cycles. This happens because of the concentration of fissile material existing in the fuel assemblies in the core decreases to values such that it is not more possible to keep the reactor operating producing energy at normal rated power. Therefore, the refueling optimization for a nuclear power plant is in fact a multi-cycle problem. A typical multi-cycle reload optimization depends on several kinds of relationships: one is the relationship between the locations where the fuel assemblies are placed for a specified fuel cycle; another is the relationship between fuel loading patterns for the subsequent fuel cycles. This makes the problem very complex and difficult to solve. Until the moment, all the presented proposals for solution are far from solving the multi-cycle optimization problems in reactor fuel management. In this work, we will show preliminary studies of possible solutions for a typical multi-cycle reload optimization problem trying to consider most important restrictions of a real model. In the initial comparisons, the optimization results will be compared with those obtained by the successive single cycle optimizations. (author)
Relationship between basic nuclear data and LWR fuel cycle parameters
International Nuclear Information System (INIS)
Becker, M.; Harris, D.R.; Quan, B.; Ryskamp, J.M.
1979-01-01
An interactive system has been developed at RPI to analyze the sensitivity of water reactor fuel cycle parameters and costs to uncertainties in nuclear data. A sequence of batch depletion, core analysis, and fuel cost codes (referred to as Path B) determines the changes in fuel cycle parameters and costs for changes in few-group microscopic cross sections, in fission yields, and in decay data. For cases that are found to be significant from Part B analysis, the sensitivities of few-group data to basic nuclear data are determined by detailed calculations (referred to as Path A). Analyses of pressurized and boiling water reactors with recycle and throwaway options show substantial sensitivities of fuel cycle parameters and costs, particularly to thermal and resonance nuclear data for fissile nuclides. The results bring out the importance for power reactor sensitivity analysis of dealing with the full fuel cycle including depletion of initially-loaded fuel and the building-in of actinides and fission products
Preliminary Test of Friction disk type turbine for S-CO{sub 2} cycle application
Energy Technology Data Exchange (ETDEWEB)
Baik, Seungjoon; Kim, Hyeon Tae; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)
2016-05-15
Due to the relatively mild sodium-CO{sub 2} interaction, the S-CO{sub 2} Brayton cycle can reduce the accident consequence compared to the steam Rankine cycle. Also the S-CO{sub 2} power conversion cycle can achieve high efficiency for SFR core thermal condition. Moreover, the S-CO{sub 2} power cycle can reduce the total cycle footprint due to high density of the working fluid. However, the high pressure operating condition and low viscosity of the fluid cause difficulties in designing appropriate seals and multi-stage turbo machineries. To solve the problem for designing turbo machineries in a creative way, KAIST research team tested a friction disk type turbine concept for the S-CO{sub 2} cycle application. In this paper, the investigation of the Tesla turbine and preliminary test results with compressed air are covered. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO{sub 2} power cycle applications. Due to the robust design of the fiction disk type, the Tesla turbine technology can be utilized not only for S-CO{sub 2} turbo machinery but also for the multi-phase or sludge flow turbo machinery. The preliminary test of lab-scale Tesla turbine with compressed air was conducted. The high pressure vessel was manufactured for the S-CO{sub 2} operating condition. The test will be concentrated on the turbine efficiency measurement under various conditions and development of the design methodology.
Preliminary closed Brayton cycle study for a space reactor application
International Nuclear Information System (INIS)
Guimaraes, Lamartine Nogueira Frutuoso; Carvalho, Ricardo Pinto de; Camillo, Giannino Ponchio
2007-01-01
The Nuclear Energy Division (ENU) of the Institute for Advanced Studies (IEAv) has started a preliminary design study for a Closed Brayton Cycle Loop (CBCL) aimed at a space reactor application. The main objectives of the study are to establish a starting concept for the CBCL components specifications, and to develop a demonstrative simulator of CBCL in nominal operation conditions. The ENU/IEAv preliminary design study is developing the CBCL around the NOELLE 60290 turbo machine. The actual nuclear reactor study is being conducted independently. Because of that, a conventional heat source is being used for the CBCL, in this preliminary design phase. This paper describes the steady state simulator of the CBCL operating with NOELLE 60290 turbo machine. In principle, several gases are being considered as working fluid, as for instance: air, helium, nitrogen, CO2 and gas mixtures such as helium and xenon. At this moment the simulator is running with Helium as the working fluid. Simplified models of heat and mass transfer are being developed to simulate thermal components. Future efforts will focus on keeping track of the modifications being implemented at the NOELLE 60290 turbo machine in order to build the CBCL. (author)
Preliminary closed Brayton cycle study for a space reactor application
Energy Technology Data Exchange (ETDEWEB)
Guimaraes, Lamartine Nogueira Frutuoso; Carvalho, Ricardo Pinto de [Institute for Advanced Studies, Sao Jose dos Campos, SP (Brazil)]. E-mail: guimarae@ieav.cta.br; Camillo, Giannino Ponchio [Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil)]. E-mail: gianninocamillo@gmail.com
2007-07-01
The Nuclear Energy Division (ENU) of the Institute for Advanced Studies (IEAv) has started a preliminary design study for a Closed Brayton Cycle Loop (CBCL) aimed at a space reactor application. The main objectives of the study are to establish a starting concept for the CBCL components specifications, and to develop a demonstrative simulator of CBCL in nominal operation conditions. The ENU/IEAv preliminary design study is developing the CBCL around the NOELLE 60290 turbo machine. The actual nuclear reactor study is being conducted independently. Because of that, a conventional heat source is being used for the CBCL, in this preliminary design phase. This paper describes the steady state simulator of the CBCL operating with NOELLE 60290 turbo machine. In principle, several gases are being considered as working fluid, as for instance: air, helium, nitrogen, CO2 and gas mixtures such as helium and xenon. At this moment the simulator is running with Helium as the working fluid. Simplified models of heat and mass transfer are being developed to simulate thermal components. Future efforts will focus on keeping track of the modifications being implemented at the NOELLE 60290 turbo machine in order to build the CBCL. (author)
Small particle bed reactors: Sensitivity to Brayton cycle parameters
Coiner, John R.; Short, Barry J.
Relatively simple particle bed reactor (PBR) algorithms were developed for optimizing low power closed Brayton cycle (CBC) systems. These algorithms allow the system designer to understand the relationship among key system parameters as well as the sensitivity of the PBR size and mass (a major system component) to variations in these parameters. Thus, system optimization can be achieved.
Forecast of the key parameters of the 24-th solar cycle
International Nuclear Information System (INIS)
Chumak, Oleg Vasilievich; Matveychuk, Tatiana Viktorovna
2010-01-01
To predict the key parameters of the solar cycle, a new method is proposed based on the empirical law describing the correlation between the maximum height of the preceding solar cycle and the entropy of the forthcoming one. The entropy of the forthcoming cycle may be estimated using this empirical law, if the maximum height of the current cycle is known. The cycle entropy is shown to correlate well with the cycle's maximum height and, as a consequence, the height of the forthcoming maximum can be estimated. In turn, the correlation found between the height of the maximum and the duration of the ascending branch (the Waldmeier rule) allows the epoch of the maximum, Tmax, to be estimated, if the date of the minimum is known. Moreover, using the law discovered, one can find out the analogous cycles which are similar to the cycle being forecasted, and hence, obtain the synoptic forecast of all main features of the forthcoming cycle. The estimates have shown the accuracy level of this technique to be 86%. The new regularities discovered are also interesting because they are fundamental in the theory of solar cycles and may provide new empirical data. The main parameters of the future solar cycle 24 are as follows: the height of the maximum is Wmax = 95 ± 20, the duration of the ascending branch is Ta = 4.5 ± 0.5yr, the total cycle duration according to the synoptic forecast is 11.3 yr. (research papers)
International Nuclear Information System (INIS)
Maraver, Daniel; Royo, Javier; Lemort, Vincent; Quoilin, Sylvain
2014-01-01
Highlights: • ORC optimization for different target applications. • Model developed to allow computation in subcritical and transcritical operation. • Regenerative and non-regenerative cycles evaluated through second law efficiency. • Common working fluids: R134a, R245fa, Solkatherm, n-Pentane, MDM, Toluene. • Thermodynamic and technological approaches lead to optimal design guidelines. - Abstract: The present work is focused on the thermodynamic optimization of organic Rankine cycles (ORCs) for power generation and CHP from different average heat source profiles (waste heat recovery, thermal oil for cogeneration and geothermal). The general goal is to provide optimization guidelines for a wide range of operating conditions, for subcritical and transcritical, regenerative and non-regenerative cycles. A parameter assessment of the main equipment in the cycle (expander, heat exchangers and feed pump) was also carried out. An optimization model of the ORC (available as an electronic annex) is proposed to predict the best cycle performance (subcritical or transcritical), in terms of its exergy efficiency, with different working fluids. The working fluids considered are those most commonly used in commercial ORC units (R134a, R245fa, Solkatherm, n-Pentane, Octamethyltrisiloxane and Toluene). The optimal working fluid and operating conditions from a purely thermodynamic approach are limited by the technological constraints of the expander, the heat exchangers and the feed pump. Hence, a complementary assessment of both approaches is more adequate to obtain some preliminary design guidelines for ORC units
Preliminary analysis of combined cycle of modular high-temperature gas cooled reactor
International Nuclear Information System (INIS)
Baogang, Z.; Xiaoyong, Y.; Jie, W.; Gang, Z.; Qian, S.
2015-01-01
Modular high-temperature gas cooled reactor (HTGR) is known as one of the most advanced nuclear reactors because of its inherent safety and high efficiency. The power conversion system of HTGR can be steam turbine based on Rankine cycle or gas turbine based on Brayton cycle respectively. The steam turbine system is mature and the gas turbine system has high efficiency but under development. The Brayton-Rankine combined cycle is an effective way to further promote the efficiency. This paper investigated the performance of combined cycle from the viewpoint of thermodynamics. The effect of non-dimensional parameters on combined cycle’s efficiency, such as temperature ratio, compression ratio, efficiency of compressor, efficiency of turbine, was analyzed. Furthermore, the optimal parameters to achieve highest efficiency was also given by this analysis under engineering constraints. The conclusions could be helpful to the design and development of combined cycle of HTGR. (author)
Preliminary parameter assessments of a spiral FFAG accelerator for proton therapy
International Nuclear Information System (INIS)
Smirnov, V.L.; Azaryan, N.S.; Vorozhtsov, S.B.
2013-01-01
Fixed-Field Alternating-Gradient (FFAG) accelerator was invented in the 1950-60s but never progressed beyond the model stage. Starting from 2000, new interest in this type of accelerator arose. Given advantages of the FFAG over the synchrotron, cyclotron and linac, there are many possible applications of the accelerator. Among them, we are mostly interested in acceleration of protons and light ions for hadron therapy. In this connection a preliminary set of parameters of the facility was estimated and, in particular, the magnetic sector shape and corresponding dynamical properties of the magnetic field of the accelerator were calculated. In addition, preliminary considerations about the RF system design are given.
International Nuclear Information System (INIS)
Delgado-Torres, Agustin M.; Garcia-Rodriguez, Lourdes
2010-01-01
In this paper, the coupling between the low-temperature solar organic Rankine cycle (ORC) and seawater and brackish water reverse osmosis desalination units has been carried out. Four substances have been considered as working fluids of the solar cycle (butane, isopentane, R245fa and R245ca). With these four fluids the volumetric flow of fresh water produced per unit of aperture area of stationary solar collector has been calculated. The former has been made with the optimized direct vapour generation (DVG) configuration and heat transfer fluid (HTF) configuration of the solar ORC. In the first one (DVG), working fluid of the ORC is directly heated inside the absorber of the solar collector. In the second one (HTF), a fluid different than the working fluid of the ORC (water in this paper) is heated without phase change inside the absorber of the solar collector. Once this fluid has been heated it is carried towards a heat exchanger where it is cooled. Thermal energy delivered in this cooling process is transferred to the working fluid of the ORC. Influence of condensation temperature of the ORC and regeneration's process effectiveness over productivity of the system has also been analysed. Finally, parameters of several preliminary designs of the low-temperature solar thermal driven RO desalination are supplied. R245fa is chosen as working fluid of the ORC in these preliminary designs. The information of the proposed preliminary designs can also be used, i.e., for the assessment of the use of thermal energy rejected by the solar cycle. Overall analysis of the efficiency of the solar thermal driven RO desalination technology is given with the results presented in this paper and the results obtained with the medium temperature solar thermal RO desalination system presented by the authors in previous papers. This work has been carried out within the framework of the OSMOSOL and POWERSOL projects.
Energy Technology Data Exchange (ETDEWEB)
Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda. Astrofisico Francisco Sanchez s/n. 38206 La Laguna (Tenerife) (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Universidad de Sevilla Escuela Tecnica Superior de Ingenieros, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)
2010-12-15
In this paper, the coupling between the low-temperature solar organic Rankine cycle (ORC) and seawater and brackish water reverse osmosis desalination units has been carried out. Four substances have been considered as working fluids of the solar cycle (butane, isopentane, R245fa and R245ca). With these four fluids the volumetric flow of fresh water produced per unit of aperture area of stationary solar collector has been calculated. The former has been made with the optimized direct vapour generation (DVG) configuration and heat transfer fluid (HTF) configuration of the solar ORC. In the first one (DVG), working fluid of the ORC is directly heated inside the absorber of the solar collector. In the second one (HTF), a fluid different than the working fluid of the ORC (water in this paper) is heated without phase change inside the absorber of the solar collector. Once this fluid has been heated it is carried towards a heat exchanger where it is cooled. Thermal energy delivered in this cooling process is transferred to the working fluid of the ORC. Influence of condensation temperature of the ORC and regeneration's process effectiveness over productivity of the system has also been analysed. Finally, parameters of several preliminary designs of the low-temperature solar thermal driven RO desalination are supplied. R245fa is chosen as working fluid of the ORC in these preliminary designs. The information of the proposed preliminary designs can also be used, i.e., for the assessment of the use of thermal energy rejected by the solar cycle. Overall analysis of the efficiency of the solar thermal driven RO desalination technology is given with the results presented in this paper and the results obtained with the medium temperature solar thermal RO desalination system presented by the authors in previous papers. This work has been carried out within the framework of the OSMOSOL and POWERSOL projects. (author)
Real-Time Gait Cycle Parameter Recognition Using a Wearable Accelerometry System
Directory of Open Access Journals (Sweden)
Jun-Ming Lu
2011-07-01
Full Text Available This paper presents the development of a wearable accelerometry system for real-time gait cycle parameter recognition. Using a tri-axial accelerometer, the wearable motion detector is a single waist-mounted device to measure trunk accelerations during walking. Several gait cycle parameters, including cadence, step regularity, stride regularity and step symmetry can be estimated in real-time by using autocorrelation procedure. For validation purposes, five Parkinson’s disease (PD patients and five young healthy adults were recruited in an experiment. The gait cycle parameters among the two subject groups of different mobility can be quantified and distinguished by the system. Practical considerations and limitations for implementing the autocorrelation procedure in such a real-time system are also discussed. This study can be extended to the future attempts in real-time detection of disabling gaits, such as festinating or freezing of gait in PD patients. Ambulatory rehabilitation, gait assessment and personal telecare for people with gait disorders are also possible applications.
Preliminary neutronic study on Pu-based OTTO cycle pebble bed reactor
Energy Technology Data Exchange (ETDEWEB)
Setiadipura, Topan; Zuhair [National Nuclear Energy Agency of Indonesia (BATAN), Selatan (Indonesia). Center for Nuclear Reactor Technology and Safety; Irwanto, Dwi [Bandung Institute of Technology (ITB), Bandung (Indonesia). Nuclear Physics and Biophysics Research Group
2017-12-15
The neutron physics characteristic of Pebble Bed Reactor (PBR) allows a better incineration of plutonium (Pu). An optimized design of simple PBR might give a symbiotic solution of providing a safe energy source, effective fuel utilization shown by a higher burnup value, and incineration of Pu stockpiles. This study perform a preliminary neutronic design study of a 200 MWt Once Through Then Out (OTTO) cycle PBR with Pu-based fuel. The safety criteria of the design were represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. In this preliminary phase, the parametric survey is limited to the heavy metal (HM) loading per pebble and the average axial speed of the fuel. An optimum high burnup of 419.7 MWd/kg-HM was achieved in this study. This optimum design uses a HM loading of 2.5 g/pebble with average axial fuel velocity 0.5 cm/day.
Effect of DUPIC cycle on CANDU reactor safety parameters
Energy Technology Data Exchange (ETDEWEB)
Mohamed, Nader M. A. [Atomic Energy Authority, ETRR-2, Cairo (Egypt); Badawi, Alya [Dept. of Nuclear and Radiation Engineering, Alexandria University, Alexandria (Egypt)
2016-10-15
Although, the direct use of spent pressurized water reactor (PWR) fuel in CANda Deuterium Uranium (CANDU) reactors (DUPIC) cycle is still under investigation, DUPIC cycle is a promising method for uranium utilization improvement, for reduction of high level nuclear waste, and for high degree of proliferation resistance. This paper focuses on the effect of DUPIC cycle on CANDU reactor safety parameters. MCNP6 was used for lattice cell simulation of a typical 3,411 MWth PWR fueled by UO{sub 2} enriched to 4.5w/o U-235 to calculate the spent fuel inventories after a burnup of 51.7 MWd/kgU. The code was also used to simulate the lattice cell of CANDU-6 reactor fueled with spent fuel after its fabrication into the standard 37-element fuel bundle. It is assumed a 5-year cooling time between the spent fuel discharges from the PWR to the loading into the CANDU-6. The simulation was carried out to calculate the burnup and the effect of DUPIC fuel on: (1) the power distribution amongst the fuel elements of the bundle; (2) the coolant void reactivity; and (3) the reactor point-kinetics parameters.
Energy Technology Data Exchange (ETDEWEB)
Lujan, J.M.; Tormos, B.; Salvador, F.J.; Gargar, K. [CMT-Motores Termicos, Universidad Politecnica de Valencia, Valencia (Spain)
2009-06-15
The present work consists of introducing the tests and facilities used to perform a comparative analysis of a diesel engine working with different blends of biodiesel fuel during the New European Driving Cycle. Furthermore, as a preliminary study, it was interesting to know the effects of biodiesel fuel on a common-rail high pressure injection system, those more useful in modern light duty diesel engines, as a consequence of its different physicochemical properties compared with conventional diesel fuel. As the real goal of the study is to compare fairly performance and emissions from the engine, it was essential to know any injection effects owed to fuel's own characteristics that finally would affect those parameters that will be evaluated. A complete fuel characterization for diesel and biodiesel fuels, as the EN 590 and the EN 14214 standard specifications, was performed in order to quantify the differences between both fuels. A priori, it could be thought that viscosity and density values will be the most significant parameters capable of altering the injection rate. As positive results, it was obtained that the common-rail high pressure injection system was totally blind in the injection rate measurements, even the significant differences between both fuels, taking into account the counterbalancing effects generated by two parameters mentioned before. The second part of the study deals with engine performance and pollutant emissions on an unmodified common-rail turbocharged diesel engine running with biodiesel fuel blends during the New European Driving Cycle. (author)
Energy Technology Data Exchange (ETDEWEB)
Maurya, Rakesh Kumar; Agarwal, Avinash Kumar [Engine Research Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India)
2011-04-15
Combustion in HCCI engines is a controlled auto ignition of well-mixed fuel, air and residual gas. Since onset of HCCI combustion depends on the auto ignition of fuel/air mixture, there is no direct control on the start of combustion process. Therefore, HCCI combustion becomes unstable rather easily, especially at lower and higher engine loads. In this study, cycle-to-cycle variations of a HCCI combustion engine fuelled with ethanol were investigated on a modified two-cylinder engine. Port injection technique is used for preparing homogeneous charge for HCCI combustion. The experiments were conducted at varying intake air temperatures and air-fuel ratios at constant engine speed of 1500 rpm and P-{theta} diagram of 100 consecutive combustion cycles for each test conditions at steady state operation were recorded. Consequently, cycle-to-cycle variations of the main combustion parameters and performance parameters were analyzed. To evaluate the cycle-to-cycle variations of HCCI combustion parameters, coefficient of variation (COV) of every parameter were calculated for every engine operating condition. The critical optimum parameters that can be used to define HCCI operating ranges are 'maximum rate of pressure rise' and 'COV of indicated mean effective pressure (IMEP)'. (author)
International Nuclear Information System (INIS)
Daunys, Mykolas; Sniuolis, Raimondas
2006-01-01
About 300 welded joint materials that are used in nuclear power energy were tested under monotonous tension and low cycle loading in Kaunas University of Technology together with St. Peterburg Central Research Institute of Structural Materials in 1970-2000. The main mechanical, low cycle loading and fracture characteristics of base metals, weld metals and some heat-affected zones of welded joints metals were determined during these experiments. Analytical dependences of low cycle fatigue parameters on mechanical characteristics of structural materials were proposed on the basis of a large number of experimental data, obtained by the same methods and testing equipment. When these dependences are used, expensive low cycle fatigue tests may be omitted and it is possible to compute low cycle loading curves parameters and lifetime for structural materials according to the main mechanical characteristics given in technical manuals. Dependences of low cycle loading curves parameters on mechanical characteristics for several groups of structural materials used in Russian nuclear power energy are obtained by statistical methods and proposed in this paper
Energy Technology Data Exchange (ETDEWEB)
1992-12-29
This volume documents model parameters chosen as of July 1992 that were used by the Performance Assessment Department of Sandia National Laboratories in its 1992 preliminary performance assessment of the Waste Isolation Pilot Plant (WIPP). Ranges and distributions for about 300 modeling parameters in the current secondary data base are presented in tables for the geologic and engineered barriers, global materials (e.g., fluid properties), and agents that act upon the WIPP disposal system such as climate variability and human-intrusion boreholes. The 49 parameters sampled in the 1992 Preliminary Performance Assessment are given special emphasis with tables and graphics that provide insight and sources of data for each parameter.
Preliminary Design of S-CO2 Brayton Cycle for KAIST Micro Modular Reactor
International Nuclear Information System (INIS)
Kim, Seong Gu; Kim, Min Gil; Bae, Seong Jun; Lee, Jeong Ik
2013-01-01
This paper suggests a complete modular reactor with an innovative concept of reactor cooling by using a supercritical carbon dioxide directly. Authors propose the supercritical CO 2 Brayton cycle (S-CO 2 cycle) as a power conversion system to achieve small volume of power conversion unit (PCU) and to contain the core and PCU in one vessel for the full modularization. This study suggests a conceptual design of small modular reactor including PCU which is named as KAIST Micro Modular Reactor (MMR). As a part of ongoing research of conceptual design of KAIST MMR, preliminary design of power generation cycle was performed in this study. Since the targets of MMR are full modularization of a reactor system with S-CO 2 coolant, authors selected a simple recuperated S-CO 2 Brayton cycle as a power conversion system for KAIST MMR. The size of components of the S-CO 2 cycle is much smaller than existing helium Brayton cycle and steam Rankine cycle, and whole power conversion system can be contained with core and safety system in one containment vessel. From the investigation of the power conversion cycle, recompressing recuperated cycle showed higher efficiency than the simple recuperated cycle. However the volume of heat exchanger for recompressing cycle is too large so more space will be occupied by heat exchanger in the recompressing cycle than the simple recuperated cycle. Thus, authors consider that the simple recuperated cycle is more suitable for MMR. More research for the KAIST MMR will be followed in the future and detailed information of reactor core and safety system will be developed down the road. More refined cycle layout and design of turbomachinery and heat exchanger will be performed in the future study
Preliminary Estimation of Kappa Parameter in Croatia
Stanko, Davor; Markušić, Snježana; Ivančić, Ines; Mario, Gazdek; Gülerce, Zeynep
2017-12-01
Spectral parameter kappa κ is used to describe spectral amplitude decay “crash syndrome” at high frequencies. The purpose of this research is to estimate spectral parameter kappa for the first time in Croatia based on small and moderate earthquakes. Recordings of local earthquakes with magnitudes higher than 3, epicentre distances less than 150 km, and focal depths less than 30 km from seismological stations in Croatia are used. The value of kappa was estimated from the acceleration amplitude spectrum of shear waves from the slope of the high-frequency part where the spectrum starts to decay rapidly to a noise floor. Kappa models as a function of a site and distance were derived from a standard linear regression of kappa-distance dependence. Site kappa was determined from the extrapolation of the regression line to a zero distance. The preliminary results of site kappa across Croatia are promising. In this research, these results are compared with local site condition parameters for each station, e.g. shear wave velocity in the upper 30 m from geophysical measurements and with existing global shear wave velocity - site kappa values. Spatial distribution of individual kappa’s is compared with the azimuthal distribution of earthquake epicentres. These results are significant for a couple of reasons: to extend the knowledge of the attenuation of near-surface crust layers of the Dinarides and to provide additional information on the local earthquake parameters for updating seismic hazard maps of studied area. Site kappa can be used in the re-creation, and re-calibration of attenuation of peak horizontal and/or vertical acceleration in the Dinarides area since information on the local site conditions were not included in the previous studies.
Exergy analysis and parameter study on a novel auto-cascade Rankine cycle
International Nuclear Information System (INIS)
Bao, Junjiang; Zhao, Li
2012-01-01
A novel auto-cascade Rankine cycle (ARC) is proposed to reduce thermodynamics irreversibility and improve energy utilization. Like the Kalina cycle, the working fluid for the ARC is zeotropic mixture, which can improve the system efficiency due to the temperature slip that zeotropic mixtures exhibit during phase change. Unlike the Kalina cycle, two expanders are included in the ARC rather than a expander and a throttling valve in the Kalina cycle, which means more work can be obtained. Using the exhaust gas as the heat source and water as the heat sink, a program is written by Matlab 2010a to carry out exergy analysis and parameter study on the ARC. Results show that the R245fa mass fraction in the primary circuit exists an optimum value with respect to the minimum total cycle irreversibility. The largest exergy loss occurs in evaporator, followed by the superheater, condenser, regenerator and IHE (Internal heat exchanger). As the R245fa mass fraction increases, the exergy losses of different components vary diversely. With the evaporation pressure rises, the total cycle irreversibility decreases and work output increases. Separator temperature has a greater influence on the system performance than superheating temperature. Compared with ORC (organic Rankine cycle) and Kalina cycle in the literature, the ARC has proven to be thermodynamically better. -- Highlights: ► We have proposed a novel auto-cascade Rankine cycle (ARC) system. ► The zeotropic mixture Isopentane/R245fa is employed in this system. ► Exergy analysis and parameter study on the ARC are presented. ► Compared with ORC and Kalina cycle in the literature, the ARC has proven to be thermodynamically better.
Preliminary core design of IRIS-50
International Nuclear Information System (INIS)
Petrovic, Bojan; Franceschini, Fausto
2009-01-01
IRIS-50 is a small, 50 MWe, advanced PWR with integral primary system. It evolved employing the same design principles as the well known medium size (335 MWe) IRIS. These principles include the 'safety-by-design' philosophy, simple and robust design, and deployment flexibility. The 50 MWe design addresses the needs of specific applications (e.g., power generation in small regional grids, water desalination and biodiesel production at remote locations, autonomous power source for special applications, etc.). Such applications may favor or even require longer refueling cycles, or may have some other specific requirements. Impact of these requirements on the core design and refueling strategy is discussed in the paper. Trade-off between the cycle length and other relevant parameters is addressed. A preliminary core design is presented, together with the core main reactor physics performance parameters. (author)
Kalabukhov, D. S.; Radko, V. M.; Grigoriev, V. A.
2018-01-01
Ultra-low power turbine drives are used as energy sources in auxiliary power systems, energy units, terrestrial, marine, air and space transport within the confines of shaft power N td = 0.01…10 kW. In this paper we propose a new approach to the development of surrogate models for evaluating the integrated efficiency of multistage ultra-low power impulse turbine with pressure stages. This method is based on the use of existing mathematical models of ultra-low power turbine stage efficiency and mass. It has been used in a method for selecting the rational parameters of two-stage axial ultra-low power turbine. The article describes the basic features of an algorithm for two-stage turbine parameters optimization and for efficiency criteria evaluating. Pledged mathematical models are intended for use at the preliminary design of turbine drive. The optimization method was tested at preliminary design of an air starter turbine. Validation was carried out by comparing the results of optimization calculations and numerical gas-dynamic simulation in the Ansys CFX package. The results indicate a sufficient accuracy of used surrogate models for axial two-stage turbine parameters selection
Comparison of several hydrological cycle parameters in Croatia for two periods
International Nuclear Information System (INIS)
Pandzic, Kreso; Trninic, Dusan
2004-01-01
Comparison of several hydrological cycle parameter averages for two periods in Croatia is considered. Parameters are: yearly averages of: 2m air temperature, precipitation amounts, potential and real evapotranspiration amounts. A basic period (1951-1980) and period for comparison (1981-1997) have been chosen. (These periods accepted at The First Sub-Regional Expert Meeting on the 'Assesment of Climate Change Impacts on the Hydrological Cycles in South-Eastern Europe' held in Sofia (Bulgaria) 17-20 February 1999.) Differences between two period averages for 30 weather stations have been calculated. Temperature differences and those for potential evaporation are positive while for precipitation they are mainly negative. Real evaporation differences for two periods are an exception i.e. they are positive in continental but negative in Mediterranean part of Croatia. These results agree with global warming trend. (Author)
Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A
DEFF Research Database (Denmark)
Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa
2016-01-01
Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary...
van Sonsbeek, Gerda R; van der Kolk, Johannes H; van Leeuwen, Johannes P T M; Schaftenaar, Willem
2011-05-01
Hypocalcemia is a well known cause of dystocia in animals, including elephants in captivity. In order to study calcium metabolism in elephants, it is of utmost importance to use properly validated assays, as these might be prone to specific matrix effects in elephant blood. The aim of the current study was to conduct preliminary work for validation of various parameters involved in calcium metabolism in both blood and urine of captive elephants. Basal values of these parameters were compared between Asian elephants (Elephas maximus) and African elephants (Loxodonta africana). Preliminary testing of total calcium, inorganic phosphorus, and creatinine appeared valid for use in plasma and creatinine in urine in both species. Furthermore, measurements of bone alkaline phosphatase and N-terminal telopeptide of type I collagen appeared valid for use in Asian elephants. Mean heparinized plasma ionized calcium concentration and pH were not significantly affected by 3 cycles of freezing and thawing. Storage at 4 °C, room temperature, and 37 °C for 6, 12, and 24 hr did not alter the heparinized plasma ionized calcium concentration in Asian elephants. The following linear regression equation using pH (range: 6.858-7.887) and ionized calcium concentration in heparinized plasma was utilized: iCa(7.4) (mmol/l) = -2.1075 + 0.3130·pH(actual) + 0.8296·iCa(actual) (mmol/l). Mean basal values for pH and plasma in Asian elephant whole blood were 7.40 ± 0.048 and 7.49 ± 0.077, respectively. The urinary specific gravity and creatinine concentrations in both Asian and African elephants were significantly correlated and both were significantly lower in Asian elephants. © 2011 The Author(s)
Preliminary thermodynamic study for an efficient turbo-blower external combustion Rankine cycle
Romero Gómez, Manuel; Romero Gómez, Javier; Ferreiro Garcia, Ramón; Baaliña Insua, Álvaro
2014-08-01
This research paper presents a preliminary thermodynamic study of an innovative power plant operating under a Rankine cycle fed by an external combustion system with turbo-blower (TB). The power plant comprises an external combustion system for natural gas, where the combustion gases yield their thermal energy, through a heat exchanger, to a carbon dioxide Rankine cycle operating under supercritical conditions and with quasi-critical condensation. The TB exploits the energy from the pressurised exhaust gases for compressing the combustion air. The study is focused on the comparison of the combustion system's conventional technology with that of the proposed. An energy analysis is carried out and the effect of the flue gas pressure on the efficiency and on the heat transfer in the heat exchanger is studied. The coupling of the TB results in an increase in efficiency and of the convection coefficient of the flue gas with pressure, favouring a reduced volume of the heat exchanger. The proposed innovative system achieves increases in efficiency of around 12 % as well as a decrease in the heat exchanger volume of 3/5 compared with the conventional technology without TB.
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Stachel Aleksander A.
2015-03-01
Full Text Available In the paper presented have been the results of the analysis of effectiveness of operation of binary power plant consisting of combined two Clausius-Rankine cycles, namely the binary cycle with water as a working fluid in the upper cycle and organic substance as a working fluid in the lower cycle, as well as a single fluid component power plant operating also in line with the C-R cycle for superheated steam, with water as a working fluid. The influence of the parameters of superheated steam in the upper cycle has been assessed as well as the type of working fluid in the lower cycle. The results of calculations have been referred to the single-cycle classical steam power plant operating at the same parameters of superheated steam and the same mass flow rate of water circulating in both cycles. On the basis of accomplished analysis it has been shown that the binary power plant shows a greater power with respect to the reference power plant.
International Nuclear Information System (INIS)
Olumayegun, Olumide; Wang, Meihong; Kelsall, Greg
2017-01-01
Highlights: • Nitrogen closed Brayton cycle for small modular sodium-cooled fast reactor studied. • Thermodynamic modelling and analysis of closed Brayton cycle performed. • Two-shaft configuration proposed and performance compared to single shaft. • Preliminary design of heat exchangers and turbomachinery carried out. - Abstract: Sodium-cooled fast reactor (SFR) is considered the most promising of the Generation IV reactors for their near-term demonstration of power generation. Small modular SFRs (SM-SFRs) have less investment risk, can be deployed more quickly, are easier to operate and are more flexible in comparison to large nuclear reactor. Currently, SFRs use the proven Rankine steam cycle as the power conversion system. However, a key challenge is to prevent dangerous sodium-water reaction that could happen in SFR coupled to steam cycle. Nitrogen gas is inert and does not react with sodium. Hence, intercooled closed Brayton cycle (CBC) using nitrogen as working fluid and with a single shaft configuration has been one common power conversion system option for possible near-term demonstration of SFR. In this work, a new two shaft nitrogen CBC with parallel turbines was proposed to further simplify the design of the turbomachinery and reduce turbomachinery size without compromising the cycle efficiency. Furthermore, thermodynamic performance analysis and preliminary design of components were carried out in comparison with a reference single shaft nitrogen cycle. Mathematical models in Matlab were developed for steady state thermodynamic analysis of the cycles and for preliminary design of the heat exchangers, turbines and compressors. Studies were performed to investigate the impact of the recuperator minimum terminal temperature difference (TTD) on the overall cycle efficiency and recuperator size. The effect of turbomachinery efficiencies on the overall cycle efficiency was examined. The results showed that the cycle efficiency of the proposed
International Nuclear Information System (INIS)
Liu, Xiaomin; Wang, Xing; Zhang, Chuhua
2014-01-01
The main purpose of this paper is to analyze the sensitivity of system parameters to the performance of the Organic Rankine Cycle (ORC) system quantitatively. A thermodynamic model of the ORC system for binary-cycle geothermal power plants has been developed and verified. The system parameters, such as working fluid, superheat temperature, pinch temperature difference in evaporator and condenser, evaporating temperature, the isentropic efficiencies of the cycle pump and radial inflow turbine are selected as six factors for orthogonal design. The order of factors sensitivity on performance indices of the net power output of the ORC system, the thermal efficiency, the size parameter of radial inflow turbine, the power decrease factor of the pump and the total heat transfer capacity are determined by the range obtained from the orthogonal design. At different geothermal temperatures, the ranges of the six factors corresponding to performance indices are analyzed respectively. The results show that the geothermal temperature influences the range of the factors to the net power output, SP factor of radial inflow turbine, and the total heat transfer capacity, but it has no effect for the range of the factors for the thermal efficiency and the power decrease factor of the pump. The evaporating temperature is always the primary or secondary factor that influence the thermodynamic and economic performance of the ORC system. This study would provide useful references for determining the proper design variables in the performance optimization of the ORC system at different geothermal temperatures. - Highlights: • Evaporating temperature has significant effect on performance of ORC system. • Order of system parameters' sensitivity to the performance of ORC is revealed. • Effect of system parameters on performance indices vary with geothermal temperature. • Geothermal temperature has no effect on range of six factors to the size of turbine
The Vulnerability of Some Networks including Cycles via Domination Parameters
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Tufan Turaci
2016-01-01
Full Text Available Let G=(V(G,E(G be an undirected simple connected graph. A network is usually represented by an undirected simple graph where vertices represent processors and edges represent links between processors. Finding the vulnerability values of communication networks modeled by graphs is important for network designers. The vulnerability value of a communication network shows the resistance of the network after the disruption of some centers or connection lines until a communication breakdown. The domination number and its variations are the most important vulnerability parameters for network vulnerability. Some variations of domination numbers are the 2-domination number, the bondage number, the reinforcement number, the average lower domination number, the average lower 2-domination number, and so forth. In this paper, we study the vulnerability of cycles and related graphs, namely, fans, k-pyramids, and n-gon books, via domination parameters. Then, exact solutions of the domination parameters are obtained for the above-mentioned graphs.
Preliminary research results for parameter diagnostics of intense pulsed ion beams
International Nuclear Information System (INIS)
Yang Hailiang; Qiu Aici; Sun Jianfeng; He Xiaoping; Tang Junping; Wang Haiyang; Li Jingya; Ren Shuqing; Huang Jianjun; Zhang Jiasheng; Peng Jianchang; Ouyang Xiaoping; Zhang Guoguang; Li Hongyu
2004-01-01
The preliminary experimental results for parameter diagnostics of intense pulsed ion beams from the FLASH II accelerator were reported. The ion number of an intense pulsed ion beam were experimentally determined by monitoring delayed radioactivity from protons induced nuclear reactions in a 12 C target. The prompt γ-rays and diode Bremsstrahlung X-rays were measured with PIN semi-conductor detector and a ST401 plastic scintillator detector. The Bremsstrahlung distribution outside of the drift tube was detected with a thermoluminescent detector and the shielding design was also determined. The current densities of beam were measured with biased ion collector array. The ion beams were also recorded with a CR-39 detector. (author)
Directory of Open Access Journals (Sweden)
Qingsong Zhang
2015-01-01
Full Text Available For practical purposes, the curtain grouting method is an effective method to treat geological disasters and can be used to improve the strength and permeability resistance of surrounding rock. Selection of the optimal parameters of grouting reinforcement cycle especially reinforcement cycle thickness is one of the most interesting areas of research in curtain grouting designs. Based on the fluid-structure interaction theory and orthogonal analysis method, the influence of reinforcement cycle thickness, elastic modulus, and permeability on water inflow of tunnel after grouting and stability of surrounding rock was analyzed. As to the water inflow of tunnel after grouting used as performance evaluation index of grouting reinforcement cycle, it can be concluded that the permeability was the most important factor followed by reinforcement cycle thickness and elastic modulus. Furthermore, pore water pressure field, stress field, and plastic zone of surrounding rock were calculated by using COMSOL software under different conditions of reinforcement cycle thickness. It also can be concluded that the optimal thickness of reinforcement cycle and permeability can be adopted as 8 m and 1/100 of the surrounding rock permeability in the curtain grouting reinforcement cycle. The engineering case provides a reference for similar engineering.
Directory of Open Access Journals (Sweden)
Andrea Meroni
2016-04-01
Full Text Available Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary turbine design model, the details of the validation and a sensitivity analysis on the main parameters, in order to minimize the number of decision variables in the subsequent turbine design optimization. Part B analyzes the application of the combined turbine and cycle designs on a selected case study, which was performed in order to show the advantages of the adopted methodology. Part A presents a one-dimensional turbine model and the results of the validation using two experimental test cases from literature. The first case is a subsonic turbine operated with air and investigated at the University of Hannover. The second case is a small, supersonic turbine operated with an organic fluid and investigated by Verneau. In the first case, the results of the turbine model are also compared to those obtained using computational fluid dynamics simulations. The results of the validation suggest that the model can predict values of efficiency within ± 1.3%-points, which is in agreement with the reliability of classic turbine loss models such as the Craig and Cox correlations used in the present study. Values similar to computational fluid dynamics simulations at the midspan were obtained in the first case of validation. Discrepancy below 12 % was obtained in the estimation of the flow velocities and turbine geometry. The values are considered to be within a
Bozeman, M.; Raymond, P.
2005-05-01
Autotrophic and heterotrophic organisms confer different effects on nutrient cycling, especially on carbon (C). In stream ecosystems, net ecosystem production determines the amount and form of C exported; however any transformation due to different respiratory (R) mechanisms are not separated. These mechanisms highly influence the form and lability of the C transported. To understand the current state of knowledge and estimate the importance of autotrophic versus heterotrophic R, we obtained a range of respiratory rates from the literature and modeled effects of different balances of rates on bulk dissolved inorganic and organic C chemistry. Preliminary results show that a wide range of estimates of autotrophic R exist and that these can effect bulk properties of exported C. While specific effects are highly dependent upon physical structure of the study watershed, we offer that separating R mechanisms provides further insight into ecosystem C cycling. We also propose a method to measure autotrophic and heterotrophic R at the ecosystem scale and obtain watershed-level estimates of the importance of these processes on C cycling.
Uranium-thorium fuel cycle in a very high temperature hybrid system
International Nuclear Information System (INIS)
Hernandez, C.R.G.; Oliva, A.M.; Fajardo, L.G.; Garcia, J.A.R.; Curbelo, J.P.; Abadanes, A.
2011-01-01
Thorium is a potentially valuable energy source since it is about three to four times as abundant as Uranium. It is also a widely distributed natural resource readily accessible in many countries. Therefore, Thorium fuels can complement Uranium fuels and ensure long term sustainability of nuclear power. The main advantages of the use of a hybrid system formed by a Pebble Bed critical nuclear reactor and two Pebble Bed Accelerator Driven Systems (ADSs) using a Uranium-Thorium (U + Th) fuel cycle are shown in this paper. Once-through and two step U + Th fuel cycle was evaluated. With this goal, a preliminary conceptual design of a hybrid system formed by a Graphite Moderated Gas-Cooled Very High Temperature Reactor and two ADSs is proposed. The main parameters related to the neutronic behavior of the system in a deep burn scheme are optimized. The parameters that describe the nuclear fuel breeding and Minor Actinide stockpile are compared with those of a simple Uranium fuel cycle. (author)
A preliminary concept of stochastic model of the tritium cycle in a fusion reactor
International Nuclear Information System (INIS)
Taczanowski, S.
1988-01-01
A preliminary concept of stochastic model of the tritium circulation in a fusion reactor was elaborated in purpose of determining the necessary minimum and current tritium inventory in real circumstances. A random character of reactor operation was assumed what is especially valid in the starting phase being of particularly low reliability of the assembly. A system of differential equations with random initial conditions describing the tritium cycle was solved for both operation and break states of the reactor. The distribution of the moments and of the number of breaks in the reactor operation was discussed and the possibilities of further development of the present model are indicated. 5 refs., 2 figs. (author)
Directory of Open Access Journals (Sweden)
Roberto Capata
2014-11-01
Full Text Available Nowadays, the Organic Rankine Cycle (ORC system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.; from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW. Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc. or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.. These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo-expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar, imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen
Heavy water reactors on the denatured thorium cycles
International Nuclear Information System (INIS)
1978-05-01
This paper presents preliminary technical and economic data to INFCE on the denatured U-233/Thorium fuel cycle for use in early comparisons of alternate nuclear systems. The once-through uranium fuel cycle is discussed in a companion paper. In presenting this preliminary information at this time, it is recognized that there are several other denatured thorium fuel cycles of potential interest, such as the U-235/thorium cycle which could be implemented at an earlier date. Information on these alternate cycles is currently being developed, and will be provided to INFCE when available
Energy Technology Data Exchange (ETDEWEB)
Rhee, Hyun-Me; Kim, Min Kyu; Choi, In-Kil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Sheen, Dong-Hoon [Chonnam National University, Gwangju (Korea, Republic of)
2014-10-15
The tsunami hazard analysis has been based on the seismic hazard analysis. The seismic hazard analysis has been performed by using the deterministic method and the probabilistic method. To consider the uncertainties in hazard analysis, the probabilistic method has been regarded as attractive approach. The various parameters and their weight are considered by using the logic tree approach in the probabilistic method. The uncertainties of parameters should be suggested by analyzing the sensitivity because the various parameters are used in the hazard analysis. To apply the probabilistic tsunami hazard analysis, the preliminary study for the Ulchin NPP site had been performed. The information on the fault sources which was published by the Atomic Energy Society of Japan (AESJ) had been used in the preliminary study. The tsunami propagation was simulated by using the TSUNAMI{sub 1}.0 which was developed by Japan Nuclear Energy Safety Organization (JNES). The wave parameters have been estimated from the result of tsunami simulation. In this study, the sensitivity analysis for the fault sources which were selected in the previous studies has been performed. To analyze the effect of the parameters, the sensitivity analysis for the E3 fault source which was published by AESJ was performed. The effect of the recurrence interval, the potential maximum magnitude, and the beta were suggested by the sensitivity analysis results. Level of annual exceedance probability has been affected by the recurrence interval.. Wave heights have been influenced by the potential maximum magnitude and the beta. In the future, the sensitivity analysis for the all fault sources in the western part of Japan which were published AESJ would be performed.
Fréour, Thomas; Jean, Miguel; Mirallié, Sophie; Dubourdieu, Sophie; Barrière, Paul
2010-04-01
To study the potential of CASA parameters in frozen-thawed donor semen before and after preparation on silica gradient as predictors of pregnancy in IUI with donor semen cycles. CASA parameters were measured in thawed donor semen before and after preparation on a silica gradient in 132 couples undergoing 168 IUI cycles with donor semen. The evolution of these parameters throughout this process was calculated. The relationship with cycle outcome was then studied. Clinical pregnancy rate was 18.4% per cycle. CASA parameters on donor semen before or after preparation were not significantly different between pregnancy and failure groups. However, amplitude of lateral head displacement (ALH) of spermatozoa improved in all cycles where pregnancy occurred, thus predicting pregnancy with a sensitivity of 100% and a specificity of 20%. Even if CASA parameters do not seem to predict pregnancy in IUI with donor semen cycles, their evolution during the preparation process should be evaluated, especially for ALH. However, the link between ALH improvement during preparation process and pregnancy remains to be explored. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.
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S. Bulatović
2014-10-01
Full Text Available Low cycle fatigue test was performed in ambient atmosphere at room temperature. Cycle loading of material, in case of High strength low-alloy steel, entails modifications of its properties and in this paper is therefore shown behavior of fatigue life using low cycle fatigue parameters. More precisely, crack initiation life of tested specimens was computed using theory of Coffin-Manson relation during the fatigue loading. The geometry of the stabilized hysteresis loop of welded joint HSLA steel, marked as Nionikral 70, is also analyzed. This stabilized hysteresis loop is very important for determination of materials properties.
A prospective study of power cycles based on the expected sodium fast reactor parameters
International Nuclear Information System (INIS)
Herranz, L. E.; Linares, J. I.; Moratilla, B. Y.; Perez, G. D.
2010-01-01
One of the main issues that has not been solved yet in the frame of Sodium Fast Reactors (SFR) is to choose the most appropriate power conversion system. This paper explores the performance of different power cycles, from traditional to innovative layouts trying to find the optimized solution. Based on the expected reactor parameters (i.e., inlet and outlet coolant temperatures, 395 deg.C and 545 deg.C, respectively), a subcritical Rankine similar to those of fossil power plant cycles has been proposed as a reference layout. Then, alternative layouts based on innovative Rankine and Brayton cycles have been investigated. Two Rankine supercritical layouts have been modeled and analyzed: one of them, adopted from the Supercritical Water Reactor of GIV (one reheater, nine pre-heaters and one moisture separator) and the other similar to some fossil plants (two reheaters, nine pre-heaters with no moisture separator). Simple Brayton cycle configurations based on Helium has been also studied. Several layouts have been modeled to study the effects of: inter-cooling between compression stages, absence of an intermediate loop and coupling of an organic Rankine cycle (ORC). (authors)
A Study on Stability of Limit Cycle Walking Model with Feet: Parameter Study
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Yonggwon Jeon
2013-01-01
Full Text Available In this paper, two kinds of feet, namely, curved and flat feet, are added to limit cycle walking model to investigate its stability properties. Although both models are already proposed and are investigated, most previous works are focused on efficiency and gait behaviors. Only the stability properties of the simplest walking model conceived Garcia et al. are well defined. Therefore, there is still a need for a precise research on the effect of feet, especially in the view of local stability, bifurcation route to chaos, global stability, falling boundary and energy balance line. Therefore, this article revisits the stability analysis of limit cycle walking model with various foot shape. To analyze the effects of feet, we re-derive the equation of motion of modified models by adding one more parameter of foot shape than the simplest walking model. Also, the falling boundary and energy balance line of modified models are derived to get proper initial conditions for stable walking and to explain global stability. Simulation results show us that the curved feet can enlarge both stable walking range and area of basin of attraction while the case of flat feet depends on foot shape parameter.
International Nuclear Information System (INIS)
Radhi, Hassan; Sharples, Stephen
2013-01-01
On a global scale, the Gulf Corporation Council Countries (GCCC), including Bahrain, are amongst the top countries in terms of carbon dioxide emissions per capita. Building authority in Bahrain has set a target of 40% reduction of electricity consumption and associated CO 2 emissions to be achieved by using facade parameters. This work evaluates how the life cycle CO 2 emissions of buildings are affected by facade parameters. The main focus is placed on direct and indirect CO 2 emissions from three contributors, namely, chemical reactions during production processes (Pco 2 ), embodied energy (Eco 2 ) and operational energy (OPco 2 ). By means of the life cycle assessment (LCA) methodology, it has been possible to show that the greatest environmental impact occurs during the operational phase (80–90%). However, embodied CO 2 emissions are an important factor that needs to be brought into the systems used for appraisal of projects, and hence into the design decisions made in developing projects. The assessment shows that masonry blocks are responsible for 70–90% of the total CO 2 emissions of facade construction, mainly due to their physical characteristics. The highest Pco 2 emissions factors are those of window elements, particularly aluminium frames. However, their contribution of CO 2 emissions depends largely on the number and size of windows. Each square metre of glazing is able to increase the total CO 2 emissions by almost 30% when compared with the same areas of opaque walls. The use of autoclaved aerated concrete (AAC) walls reduces the total life cycle CO 2 emissions by almost 5.2% when compared with ordinary walls, while the use of thermal insulation with concrete wall reduces CO 2 emissions by 1.2%. The outcome of this work offers to the building industry a reliable indicator of the environmental impact of residential facade parameters. - Highlights: ► Life cycle carbon assessment of façade parameters. ► Greatest environmental impact occurs
International Nuclear Information System (INIS)
Penn, W.J.
1979-05-01
Uranium resource utilization and economic considerations provide incentives to study alternative fuel cycles as future options to the PHWR natural uranium cycle. Preliminary studies to define the most favourable alternatives and their possible introduction dates are discussed. The important and uncertain components which influence option selection are reviewed, including nuclear capacity growth, uranium availability and demand, economic potential, and required technological developments. Finally, a summary of Ontario Hydro's program to further assess cycle selection and define development needs is given. (auth)
International Nuclear Information System (INIS)
Caggiano, J.A.
1982-03-01
Preliminary data on strain rate, seismicity, and estimated earthquake source parameters suggest limitations on the extent of postulated faulting and its impact on a nuclear waste repository in Columbia River basalt. Structural relief of dated basalt flows, attitude of Pliocene sediments, geodetic surveys, size and distribution of earthquakes, and focal mechanism solutions indicate that deformation of basalt under north-south compression was under way in the Miocene and has continued on existing structures at an average rate of much less than 1 mm/yr in the Pasco Basin. Lengths and displacements of mapped faults suggest limits on the postulated fault that could intersect a repository and produce an earthquake of about magnitude 6.5. Using a credible earthquake permits calculation of preliminary source parameters for risk assessment modeling during a single episode of slip on the postulated new fault and indicates displacement of less than or equal to 1, m on a steeply dipping fault of less than or equal to 50 km length could occur. Preliminary source parameter calculations suggest that displacements of less than or equal to 2 cm may occur during microearthquakes in swarms. The area of fault rupture may be tens of square meters up to a few square kilometers, suggesting slip on joints. Seismic moments for postulated earthquakes in the interconnecting fault and microearthquake scenarios compare favorably with reported values for similar-sized earthquakes in different media and suggest that the estimated fault parameters are reasonable until an adequate tectonic model has been developed
The SPS beam parameters, the operational cycle, and proton sharing with the SHiP facility
Arduini, Gianluigi; Gatignon, Lau; Cornelis, Karel
2015-01-01
The SHiP experiment aims at acquiring a total of 4×1019 protons on target per year. Based on demonstrated SPS performance for CNGS, the expected proton sharing between the TCC2 targets and SHiP is estimated taking into account the constraints in the super-cycle composition. We review the SPS beam parameters, the operational cycles taking into account the concurrent operation of the SPS as LHC injector and for the TCC2 experiments and the limitations on the maximum possible power dissipation and the expected sharing of the protons on target of the SHiP facility with the TCC2 targets. As a typical example this aim could be achieved while maintaining a duty cycle for the other fixed target experiments of about 18%.
Directory of Open Access Journals (Sweden)
Tayfun Kutlu
2017-03-01
Full Text Available Objective: To determine some major characteristic differences between two consecutive successful and unsuccessful intracytoplasmic sperm injection (ICSI cycles in poor responders. Materials and Methods: Sixty women with poor ovarian response as determined using the Bologna criteria underwent ICSI cycles following an unsuccessful trial. Some parameters of both cycles including age, body mass index (BMI, serum follicle-stimulating hormone (FSH and estradiol levels, antral follicle count, gonadotropin dosage, duration of stimulation, antagonist starting day, duration of antagonist administration, endometrial thickness at trigger day, number of total and fertilized oocytes, embryo transfer day, number of embryo cells, and fertilization rate were compared in the same patients to identify predictors of cycles with clinical pregnancy. Results: The mean age, BMI, serum FSH, estradiol concentrations, and antral follicle count were 35.9 years (range, 30-42 years, 25.9 kg/m2 (range, 18.4-33.5 kg/m2, 10.9 IU/mL (range, 7-13 IU/mL, 52.9 pg/mL (range, 11.6-75 pg/mL, and 4.7 (range, 2-10, respectively. A comparison of cycle characteristics showed a significantly higher total number of mature and fertilized oocytes in successful cycles. The fertilization rate was also significantly higher in cycles with clinical pregnancy. Early initiation of antagonist was shown to result in favorable outcomes. A comparison of embryo characteristics showed that transfer of higher-stage embryos and embryos with higher numbers of cells had a significant impact on cycle outcomes. Conclusion: Our comparison of parameters of failed and successful ICSI cycles in poor responders revealed significantly earlier antagonist initiation, higher total number of mature and fertilized oocytes, fertilization rate, and significantly higher stage of embryo development and cell numbers at transfer in cycles that resulted in clinical pregnancy.
Temporal-spatial parameters of the upper limb during a Reach & Grasp Cycle for children.
Butler, Erin E; Ladd, Amy L; Lamont, Lauren E; Rose, Jessica
2010-07-01
The objective of this study was to characterize normal temporal-spatial patterns during the Reach & Grasp Cycle and to identify upper limb motor deficits in children with cerebral palsy (CP). The Reach & Grasp Cycle encompasses six sequential tasks: reach, grasp cylinder, transport to self (T(1)), transport back to table (T(2)), release cylinder, and return to initial position. Three-dimensional motion data were recorded from 25 typically developing children (11 males, 14 females; ages 5-18 years) and 12 children with hemiplegic CP (2 males, 10 females; ages 5-17 years). Within-day and between-day coefficients of variation for the control group ranged from 0 to 0.19, indicating good repeatability of all parameters. The mean duration of the Cycle for children with CP was nearly twice as long as controls, 9.5±4.3s versus 5.1±1.2s (U=37.0, P=.002), partly due to prolonged grasp and release durations. Peak hand velocity occurred at approximately 40% of each phase and was greater during the transport (T(1), T(2)) than non-transport phases (reach, return) in controls (PGrasp Cycle (rho=.957, PGrasp Cycle for quantitative evaluation of upper limb motor deficits. Copyright © 2010 Elsevier B.V. All rights reserved.
Active cooling for downhole instrumentation: Preliminary analysis and system selection
Energy Technology Data Exchange (ETDEWEB)
Bennett, G.A.
1988-03-01
A feasibility study and a series of preliminary designs and analyses were done to identify candidate processes or cycles for use in active cooling systems for downhole electronic instruments. A matrix of energy types and their possible combinations was developed and the energy conversion process for each pari was identified. The feasibility study revealed conventional as well as unconventional processes and possible refrigerants and identified parameters needing further clarifications. A conceptual design or series od oesigns for each system was formulated and a preliminary analysis of each design was completed. The resulting coefficient of performance for each system was compared with the Carnot COP and all systems were ranked by decreasing COP. The system showing the best combination of COP, exchangeability to other operating conditions, failure mode, and system serviceability is chosen for use as a downhole refrigerator. 85 refs., 48 figs., 33 tabs.
Parameter Sensitivity Study for Typical Expander-Based Transcritical CO2 Refrigeration Cycles
Directory of Open Access Journals (Sweden)
Bo Zhang
2018-05-01
Full Text Available A sensitivity study was conducted for three typical expander-based transcritical CO2 cycles with the developed simulation model, and the sensitivities of the maximum coefficient of performance (COP to the key operating parameters, including the inlet pressure of gas cooler, the temperatures at evaporator inlet and gas cooler outlet, the inter-stage pressure and the isentropic efficiency of expander, were obtained. The results showed that the sensitivity to the gas cooler inlet pressure differs greatly before and after the optimal gas cooler inlet pressure. The sensitivity to the intercooler outlet temperature in the two-stage cycles increases sharply to near zero and then keeps almost constant at intercooler outlet temperature of higher than 45 °C. However, the sensitivity stabilizes near zero when the evaporator inlet temperature is very low of −26.1 °C. In two-stage compression with an intercooler and an expander assisting in driving the first-stage compressor (TEADFC cycle, an abrupt change in the sensitivity of maximum COP to the inter-stage pressure was observed, but disappeared after intercooler outlet temperature exceeds 50 °C. The sensitivity of maximum COP to the expander isentropic efficiency increases almost linearly with the expander isentropic efficiency.
International Nuclear Information System (INIS)
Baik, Seungjoon; Heo, Jin Young; Kwon, Jinsu; Lee, Jeong Ik
2016-01-01
Among the next generation reactors, a sodium-cooled fast reactor (SFR) with the supercritical carbon dioxide (S-CO_2) Brayton cycle has been suggested as the advanced energy solution. The S-CO_2 power conversion system can achieve high efficiency with the SFR core thermal condition (450-550℃) and also can reduce the total cycle footprint due to high density of the working fluid. Moreover, the S-CO_2 power cycle can reduce the accident consequence compared to the steam Rankine cycle due to the mild sodium-CO_2 interaction. The S-CO_2 power cycle has different characteristic compare to the conventional steam Rankine cycle or gas Brayton cycle. For the turbine section, the expansion ratio is much smaller than the other cycles. Thus, different type of turbine should be evaluated for the advanced S-CO_2 technology and the KAIST research team considered a friction disk type turbine (Tesla turbine) concept for the S-CO_2 cycle applications. In this paper, the test result and analysis of a lab-scale Tesla turbine in the KAIST S-CO_2 experimental facility (S-CO_2PE) are briefly discussed. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO_2 power cycle applications. The preliminary test of a lab-scale Tesla turbine was conducted with compressed air. The generator, nozzle angle and bearing performances are tested. With the best performing nozzle angle and bearing, the Tesla turbine was tested under various S-CO_2 conditions. As a result, the S-CO_2PE facility generated electricity (0.5-5W). The isentropic efficiency was relatively low (0.8-1.3%). It seemed that, the authors need further study to understand the main mechanism and maximize the efficiency. After developing the design methodology, the design optimization will be conducted to show the applicability of the friction disk type turbine for the S-CO_2 power cycle
Huang, Rui; Zhu, Wei-Jie; Li, Jing; Gu, Yi-Qun
2014-12-01
To evaluate the changes of stage distribution of seminiferous epithelium cycle and its correlations with Leydig cell stereological parameters in aging men. Point counting method was used to analyze the stereological parameters of Leydig cells. The stage number of seminiferous epithelium cycle was calculated in the same testicular tissue samples which were used for Leydig cell stereological analysis. The aging group had shown more severe pathological changes as well as higher pathologic scores than the young group. Compared with the control group, the volume density (VV) and surface density (NA) of Leydig cells in the aging group were increased significantly. The stage number of seminiferous epithelium cycle in the aging group was decreased coincidently compared to the young group. Leydig cell Vv in the young group has a positive relationship with stages I, II, III, V and VI of seminiferous epithelium cycle, and Leydig cell NA and numerical density (NV) were positively related to stage IV. However, only the correlation between NV and stage II was found in the aging group. The stage number of seminiferous epithelium cycle was decreased in aging testes. Changes in the stage distribution in aging testes were related to the Leydig cell stereological parameters which presented as a sign of morphological changes. Copyright © 2014 Elsevier GmbH. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Radhi, Hassan, E-mail: h_alradhi@yahoo.com [Global Engineering Bureau, P.O Box 33130, Manama, Kingdom of Bahrain (Bahrain); Sharples, Stephen, E-mail: steve.sharples@liverpool.ac.uk [School of Architecture, University of Liverpool (United Kingdom)
2013-01-15
On a global scale, the Gulf Corporation Council Countries (GCCC), including Bahrain, are amongst the top countries in terms of carbon dioxide emissions per capita. Building authority in Bahrain has set a target of 40% reduction of electricity consumption and associated CO{sub 2} emissions to be achieved by using facade parameters. This work evaluates how the life cycle CO{sub 2} emissions of buildings are affected by facade parameters. The main focus is placed on direct and indirect CO{sub 2} emissions from three contributors, namely, chemical reactions during production processes (Pco{sub 2}), embodied energy (Eco{sub 2}) and operational energy (OPco{sub 2}). By means of the life cycle assessment (LCA) methodology, it has been possible to show that the greatest environmental impact occurs during the operational phase (80-90%). However, embodied CO{sub 2} emissions are an important factor that needs to be brought into the systems used for appraisal of projects, and hence into the design decisions made in developing projects. The assessment shows that masonry blocks are responsible for 70-90% of the total CO{sub 2} emissions of facade construction, mainly due to their physical characteristics. The highest Pco{sub 2} emissions factors are those of window elements, particularly aluminium frames. However, their contribution of CO{sub 2} emissions depends largely on the number and size of windows. Each square metre of glazing is able to increase the total CO{sub 2} emissions by almost 30% when compared with the same areas of opaque walls. The use of autoclaved aerated concrete (AAC) walls reduces the total life cycle CO{sub 2} emissions by almost 5.2% when compared with ordinary walls, while the use of thermal insulation with concrete wall reduces CO{sub 2} emissions by 1.2%. The outcome of this work offers to the building industry a reliable indicator of the environmental impact of residential facade parameters. - Highlights: Black-Right-Pointing-Pointer Life cycle
International Nuclear Information System (INIS)
Božnar, Marija Zlata; Grašič, Boštjan; Mlakar, Primož; Soares, Jacyra; Pereira de Oliveira, Amauri; Costa, Tássio Santos
2015-01-01
Graphical abstract: A new type of graphical presentation showing diurnal cycle of solar energy forecast. The application is possible for other parameters related to weather and green energy production. - Highlights: • The diurnal cycle of solar energy is important for the management of the electrical grid. • A solar plant’s average production depends on the statistical features of solar radiation. • The new tool – the “sunflower”, is proposed for solar energy availability representation. • The sunflower identifies and quantifies information with a clear diurnal cycle. • The sunflower diagram has been developed from the “wind rose” diagram. - Abstract: Many meteorological parameters present a natural diurnal cycle because they are directly or indirectly dependent on sunshine exposure. The solar radiation diurnal pattern is important to energy production, agriculture, prognostic models, health and general climatology. This article aims at introducing a new type of radial frequency diagram – hereafter called sunflower – for the analysis of solar radiation data in connection with energy production and also for climatological studies. The diagram is based on two-dimensional data sorting. Firstly data are sorted into classes representing hours in a day. Then the data in each hourly class is sorted into classes of the observed variable values. The relative frequencies of the value classes are shown as sections on each hour’s segment in a radial diagram. The radial diagram forms a unique pattern for each analysed dataset. Therefore it enables the quick detection of features and the comparison of several such patterns belonging to the different datasets being analysed. The sunflower diagram enables a quick and comprehensive understanding of the information about diurnal cycle of the solar radiation data. It enables in a graphical form, quick screening and long-term statistics of huge data quantities when searching for their diurnal features and
A New Dynamic Model for Nuclear Fuel Cycle System Analysis
International Nuclear Information System (INIS)
Choi, Sungyeol; Ko, Won Il
2014-01-01
The evaluation of mass flow is a complex process where numerous parameters and their complex interaction are involved. Given that many nuclear power countries have light and heavy water reactors and associated fuel cycle technologies, the mass flow analysis has to consider a dynamic transition from the open fuel cycle to other cycles over decades or a century. Although an equilibrium analysis provides insight concerning the end-states of fuel cycle transitions, it cannot answer when we need specific management options, whether the current plan can deliver these options when needed, and how fast the equilibrium can be achieved. As a pilot application, the government brought several experts together to conduct preliminary evaluations for nuclear fuel cycle options in 2010. According to Table 1, they concluded that the closed nuclear fuel cycle has long-term advantages over the open fuel cycle. However, it is still necessary to assess these options in depth and to optimize transition paths of these long-term options with advanced dynamic fuel cycle models. A dynamic simulation model for nuclear fuel cycle systems was developed and its dynamic mass flow analysis capability was validated against the results of existing models. This model can reflects a complex combination of various fuel cycle processes and reactor types, from once-through to multiple recycling, within a single nuclear fuel cycle system. For the open fuel cycle, the results of the developed model are well matched with the results of other models
International Nuclear Information System (INIS)
Poryadkova, N.A.
1984-01-01
Parameters of the cell cycle of human lymphocytes are specified, radiation effect applied at various stages of mitotic cycle on the kinetics of cell advance in the cycle is also investigated. It is shown that increasing mitotic index occurs only due to the introduction of cells into the first mitosis. It is not excluded that cells ready to enter the second mitosis died with greater probability as after second synthesis they contained two-fold amount of BDU (5-brominedesoxiuridine) than cells of the first mitosis. In all cases with irradiation of cells of the third mitosis were not found
Energy Technology Data Exchange (ETDEWEB)
Baik, Seungjoon; Heo, Jin Young; Kwon, Jinsu; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)
2016-10-15
Among the next generation reactors, a sodium-cooled fast reactor (SFR) with the supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle has been suggested as the advanced energy solution. The S-CO{sub 2} power conversion system can achieve high efficiency with the SFR core thermal condition (450-550℃) and also can reduce the total cycle footprint due to high density of the working fluid. Moreover, the S-CO{sub 2} power cycle can reduce the accident consequence compared to the steam Rankine cycle due to the mild sodium-CO{sub 2} interaction. The S-CO{sub 2} power cycle has different characteristic compare to the conventional steam Rankine cycle or gas Brayton cycle. For the turbine section, the expansion ratio is much smaller than the other cycles. Thus, different type of turbine should be evaluated for the advanced S-CO{sub 2} technology and the KAIST research team considered a friction disk type turbine (Tesla turbine) concept for the S-CO{sub 2} cycle applications. In this paper, the test result and analysis of a lab-scale Tesla turbine in the KAIST S-CO{sub 2} experimental facility (S-CO{sub 2}PE) are briefly discussed. The KAIST research team investigated a friction disk type turbine, named as Tesla turbine, for the S-CO{sub 2} power cycle applications. The preliminary test of a lab-scale Tesla turbine was conducted with compressed air. The generator, nozzle angle and bearing performances are tested. With the best performing nozzle angle and bearing, the Tesla turbine was tested under various S-CO{sub 2} conditions. As a result, the S-CO{sub 2}PE facility generated electricity (0.5-5W). The isentropic efficiency was relatively low (0.8-1.3%). It seemed that, the authors need further study to understand the main mechanism and maximize the efficiency. After developing the design methodology, the design optimization will be conducted to show the applicability of the friction disk type turbine for the S-CO{sub 2} power cycle.
Parameters of Models of Structural Transformations in Alloy Steel Under Welding Thermal Cycle
Kurkin, A. S.; Makarov, E. L.; Kurkin, A. B.; Rubtsov, D. E.; Rubtsov, M. E.
2017-05-01
A mathematical model of structural transformations in an alloy steel under the thermal cycle of multipass welding is suggested for computer implementation. The minimum necessary set of parameters for describing the transformations under heating and cooling is determined. Ferritic-pearlitic, bainitic and martensitic transformations under cooling of a steel are considered. A method for deriving the necessary temperature and time parameters of the model from the chemical composition of the steel is described. Published data are used to derive regression models of the temperature ranges and parameters of transformation kinetics in alloy steels. It is shown that the disadvantages of the active visual methods of analysis of the final phase composition of steels are responsible for inaccuracy and mismatch of published data. The hardness of a specimen, which correlates with some other mechanical properties of the material, is chosen as the most objective and reproducible criterion of the final phase composition. The models developed are checked by a comparative analysis of computational results and experimental data on the hardness of 140 alloy steels after cooling at various rates.
Control of the parameters of attention in basketball at the stage of preliminary basic preparation
Directory of Open Access Journals (Sweden)
Olena Mitova
2015-10-01
Full Text Available Purpose: to determine the parameters of attention of basketball players aged 13–14 years old before and after the exercises of various kinds. Material and Methods: the study involved 3 teams of basketball players aged 13–14 years old from training groups. The total number of investigated people is 50. The study was carried out on the basis of Sports Children and Youth Olympic school № 5 in Dnepropetrovsk. We used the methods of theoretical analysis and synthesis of the literature, the method of analysis of documentary materials, pedagogical supervision, psychological testing, pulsometry, methods of mathematical statistics.The following techniques were used to determine the parameters of attention: «Mixed up line», proofreading test with Landoldt rings, proofreading test with letters. Results: during our research there was defined the predominantly low level of attention of basketball players at the stage of preliminary basic preparation. It was found out the specific nature of the load influences the decrease of the parameters in a greater degree, especially concentration, switching, and stability decline, the number of errors increases. Conclusions: on the basis of studies arises the necessity to improve monitoring systems in the Sports Children and Youth schools with usage of tests to determine the components of psychological readiness
International Nuclear Information System (INIS)
Yoshikawa, K.; Ishikawa, M.; Umoto, J.; Fukuyama, A.; Mitarai, O.; Okamoto, M.; Sekimoto, H.; Nagatsu, M.
1995-01-01
Preliminary key issues for a synchrotron radiation-enhanced compact fusion advanced Brayton (CFAB) cycle fusion reactor similar to the CFAR (compact fusion advanced Rankine) cycle reactor are presented. These include plasma operation windows as a function of the first wall reflectivity and related issues, to estimate an allowance for deterioration of the first wall reflectivity due to dpa effects. It was found theoretically that first wall reflectivities down to 0.8 are still adequate for operation at an energy confinement scaling of 3 times Kaye-Goldston. Measurements of the graphite first wall reflectivities at Nagoya University indicate excellent reflectivities in excess of 90% for CC-312, PCC-2S, and PD-330S in the submillimeter regime, even at high temperatures in excess of 1000K. Some engineering issues inherent to the CFAB cycle are also discussed briefly in comparison with the CFAR cycle which uses hazardous limited-resource materials but is capable of using mercury as coolant for high heat removal. The CFAB cycle using helium coolant is found to achieve higher net plant conversion efficiencies in excess 60% using a non-equilibrium magnetohydrodynamic disk generator in the moderate pressure range, even at the cost of a relatively large pumping power, and at the penalty of high temperature materials, although excellent heat removal characteristics in the moderate pressure range need to be guaranteed in the future. (orig.)
International Nuclear Information System (INIS)
Salehzadeh, A.; Khoshbakhti Saray, R.; JalaliVahid, D.
2013-01-01
Multiple energy generating cycles such as tri-generation cycles, which produce heat and cold in addition to power through burning of a primary fuel, have increasingly been used in recent decades. On the other hand, advanced exergy analysis of thermodynamic systems by splitting exergy destruction into endogenous and exogenous parts identifies internal irreversibilities of each of the components and the effect of these irreversibilities on the performance of other components. Therefore, main sources of exergy destruction in cycles can be highlighted and useful recommendations in order to improve the performance of thermodynamic cycles can be presented. In the present work, a tri-generation cycle with 100 MW power production, 70 MW heat and 9 MW cooling capacity is considered. For this tri-generation cycle, effects of various thermodynamic parameters on the amount of endogenous and exogenous exergy destructions, exergy loss and the amount of fuel consumption, are investigated. The results indicate that, increasing compressor pressure ratio, pre-heater outlet temperature and excess air leads to better combustion and lower exergy loss and fuel consumption. Increasing the mass flow rate of steam generator, while keeping the cycle outlet temperature constant and considering cooling capacity variable, lead to increase the first- and second-law efficiencies of the cycle. - Highlights: ► Advanced exergy analysis is used to analyze a tri-generation cycle. ► Increasing compressor pressure ratio leads to lower exergy loss and fuel consumption. ► Exergy loss is lowered by increasing pre-heater outlet temperature. ► Increasing the air flow rate of the cycle improves the performance of the cycle
Technical ability of new MTR high-density fuel alloys regarding the whole fuel cycle
International Nuclear Information System (INIS)
Durand, J.P.; Maugard, B.; Gay, A.
1998-01-01
The development of new fuel alloys could provide a good opportunity to improve drastically the fuel cycle on the neutronic performances and the reprocessing point of view. Nevertheless, those parameters can only be considered if the fuel manufacture feasibility has been previously demonstrated. As a matter of fact, a MTR work group involving French partners (CEA, CERCA, COGEMA) has been set up in order to evaluate the technical ability of new fuels considering the whole fuel cycle. In this paper CERCA is presenting the preliminary results of UMo and UNbZr fuel plate manufacture, CEA is comparing to U 3 Si 2 the neutronic performances of fuels such as UMo, UN, UNbZr, while COGEMA is dealing with the reprocessing feasibility. (author)
Directory of Open Access Journals (Sweden)
Emilia Ambrosini
2014-01-01
Full Text Available Cycling induced by Functional Electrical Stimulation (FES training currently requires a manual setting of different parameters, which is a time-consuming and scarcely repeatable procedure. We proposed an automatic procedure for setting session-specific parameters optimized for hemiparetic patients. This procedure consisted of the identification of the stimulation strategy as the angular ranges during which FES drove the motion, the comparison between the identified strategy and the physiological muscular activation strategy, and the setting of the pulse amplitude and duration of each stimulated muscle. Preliminary trials on 10 healthy volunteers helped define the procedure. Feasibility tests on 8 hemiparetic patients (5 stroke, 3 traumatic brain injury were performed. The procedure maximized the motor output within the tolerance constraint, identified a biomimetic strategy in 6 patients, and always lasted less than 5 minutes. Its reasonable duration and automatic nature make the procedure usable at the beginning of every training session, potentially enhancing the performance of FES-cycling training.
Energy Technology Data Exchange (ETDEWEB)
Matausek, M; Spasojevic, D; Jovic, V; Marinkovic, N [Institut za Nuklearne Nauke Boris Kidric, Belgrade (Yugoslavia)
1988-07-01
The paper presents initial activities on creating a design concept of a new thermal research reactor, which should be built according to the research and development program in the field of nuclear fuel cycle technologies. For one possible type of such a reactor basic design parameters are specified and some preliminary results of nuclear, thermal and hydrodynamic design calculations are given. (author)
International Nuclear Information System (INIS)
Lee, Jai Hyuen; Lee, Won Ae; Park, Seok Gun; Park, Dong Kook; Namgung, Hwan
2012-01-01
The clinical availability of 2 deoxy 2 [18F] fluoro D glucose (FDG) dual time point positron emission tomography/computerized tomography (DTPP) has been investigated in diverse oncologic fields. The aim of this preliminary study was to evaluate the relationship between various immunohistopathologic markers reflecting disease progression of colorectal cancer and parameters extracted from FDG DTPP in colorectal cancer patients. Forty seven patients with histologically confirmed colorectal cancer were analyzed in this preliminary study. FDG DTPP consisted of an early scan 1 h after FDG injection and a delayed scan 1.5 h after the early scan. Based on an analysis of FDG DTPP, we estimated the maximum standardized uptake value (SUV) of tumors on the early and delayed scans (SUV earlya nd SUV delayed, respectively). The retention index (RI) was calculated as follows: (SUV delayed- SUV early) x 100/ SUV early. The clinicopathological findings (size and T and N stages) and immunohistochemical factors [glucose transporter 1 (GLUT 1), hexokinase 2 (HK 2), p53, P504S, and β catenin] were analyzed by visual analysis. The RIs calculated from the SUVs ranged from -1.8 to 73.4 (31.8±15.5). The RIs were significantly higher in patients with high T stages (T3 and T4) than with low T stages (T1 and T2; P earlya nd SUV delayeda nd clinicopathologic parameters in this study. The RIs obtained from preoperative colorectal cancers had a significant relationship to tumor size, T staging, GLUT 1, and p53, in contrast to SUV earlyo r SUV delayed. Compared with previous reports, our results showed that RI can better predict GLUT 1 expression than HK 2 and other immunohistochemical markers. This study demonstrated that the RI might have the potential to be applied as a prognostic marked in preoperative colorectal cancer
Remote sensing of wetland parameters related to carbon cycling
Bartlett, David S.; Johnson, Robert W.
1985-01-01
Measurement of the rates of important biogeochemical fluxes on regional or global scales is vital to understanding the geochemical and climatic consequences of natural biospheric processes and of human intervention in those processes. Remote data gathering and interpretation techniques were used to examine important cycling processes taking place in wetlands over large geographic expanses. Large area estimation of vegetative biomass and productivity depends upon accurate, consistent measurements of canopy spectral reflectance and upon wide applicability of algorithms relating reflectance to biometric parameters. Results of the use of airborne multispectral scanner data to map above-ground biomass in a Delaware salt marsh are shown. The mapping uses an effective algorithm linking biomass to measured spectral reflectance and a means to correct the scanner data for large variations in the angle of observation of the canopy. The consistency of radiometric biomass algorithms for marsh grass when they are applied over large latitudinal and tidal range gradients were also examined. Results of a 1 year study of methane emissions from tidal wetlands along a salinity gradient show marked effects of temperature, season, and pore-water chemistry in mediating flux to the atmosphere.
A nuclear fuel cycle system dynamic model for spent fuel storage options
International Nuclear Information System (INIS)
Brinton, Samuel; Kazimi, Mujid
2013-01-01
Highlights: • Used nuclear fuel management requires a dynamic system analysis study due to its socio-technical complexity. • Economic comparison of local, regional, and national storage options is limited due to the public financial information. • Local and regional options of used nuclear fuel management are found to be the most economic means of storage. - Abstract: The options for used nuclear fuel storage location and affected parameters such as economic liabilities are currently a focus of several high level studies. A variety of nuclear fuel cycle system analysis models are available for such a task. The application of nuclear fuel cycle system dynamics models for waste management options is important to life-cycle impact assessment. The recommendations of the Blue Ribbon Committee on America’s Nuclear Future led to increased focus on long periods of spent fuel storage [1]. This motivated further investigation of the location dependency of used nuclear fuel in the parameters of economics, environmental impact, and proliferation risk. Through a review of available literature and interactions with each of the programs available, comparisons of post-reactor fuel storage and handling options will be evaluated based on the aforementioned parameters and a consensus of preferred system metrics and boundary conditions will be provided. Specifically, three options of local, regional, and national storage were studied. The preliminary product of this research is the creation of a system dynamics tool known as the Waste Management Module (WMM) which provides an easy to use interface for education on fuel cycle waste management economic impacts. Initial results of baseline cases point to positive benefits of regional storage locations with local regional storage options continuing to offer the lowest cost
International Nuclear Information System (INIS)
Omar, Noshin; Monem, Mohamed Abdel; Firouz, Yousef; Salminen, Justin; Smekens, Jelle; Hegazy, Omar; Gaulous, Hamid; Mulder, Grietus; Van den Bossche, Peter; Coosemans, Thierry; Van Mierlo, Joeri
2014-01-01
Highlights: • Extended life cycle tests. • Investigation of the battery life cycle at different working conditions. • Investigation of the impact fast charging on the battery performances. • Extraction all required relationship for development of a cycle life model. • Development of a new life cycle model. - Abstract: This paper represents the evaluation of ageing parameters in lithium iron phosphate based batteries, through investigating different current rates, working temperatures and depths of discharge. From these analyses, one can derive the impact of the working temperature on the battery performances over its lifetime. At elevated temperature (40 °C), the performances are less compared to at 25 °C. The obtained mathematical expression of the cycle life as function of the operating temperature reveals that the well-known Arrhenius law cannot be applied to derive the battery lifetime from one temperature to another. Moreover, a number of cycle life tests have been performed to illustrate the long-term capabilities of the proposed battery cells at different discharge constant current rates. The results reveal the harmful impact of high current rates on battery characteristics. On the other hand, the cycle life test at different depth of discharge levels indicates that the battery is able to perform 3221 cycles (till 80% DoD) compared to 34,957 shallow cycles (till 20% DoD). To investigate the cycle life capabilities of lithium iron phosphate based battery cells during fast charging, cycle life tests have been carried out at different constant charge current rates. The experimental analysis indicates that the cycle life of the battery degrades the more the charge current rate increases. From this analysis, one can conclude that the studied lithium iron based battery cells are not recommended to be charged at high current rates. This phenomenon affects the viability of ultra-fast charging systems. Finally, a cycle life model has been developed, which
Preliminary S-CO_2 Compressor Design for Micro Modular Reactor
International Nuclear Information System (INIS)
Lee, Jekyoung; Cho, Seong Kuk; Kim, Seong Gu; Lee, Jeong Ik
2016-01-01
Due to economic benefit of S-CO_2 Brayton cycle which is came from high efficiency and compactness, active research is currently conducted by various research groups and various approaches are suggested to take benefits of S-CO_2 Brayton cycle. KAIST research team also has been working on advanced concept for application of S-CO_2 Brayton cycle to nuclear system and Micro Modular Reactor (MMR) concept was suggested. The preliminary compressor design of S-CO_2 compressor for MMR system was carried out to observe feasibility of compressor design. Preliminary S-CO_2 compressor design for MMR system was successfully conducted and some issues are discovered from the design study. From the previous work done by Cho, conceptual design for MMR system was provided. Thus, further preliminary design should be carried out to obtain feasible S-CO_2 compressor design for MMR system. KAIST_TMD which is turbomachinery in-house code for real gases including S-CO_2 is continuously updated and currently it has 3D geometry construction and design optimization capability
Energy Technology Data Exchange (ETDEWEB)
Gagarinskiy, Alexey [National Research Centre ' ' Kurchatov Institute' ' , Moscow (Russian Federation)
2017-09-15
Since the introduction of VVERs-440, their fuel assemblies are subject to ongoing improvements. Until now, the basic structural parameters of fuel, such as rod diameter of 9.1 mm, have never changed. This paper focuses on computational estimates of basic neutronic parameters of the fuel cycle that involves assemblies consisting of fuel rods with diameter reduced to 8.9 mm.
Energy Technology Data Exchange (ETDEWEB)
Cardoni, Jeffrey N.; Kalinich, Donald A.
2014-02-01
Sandia National Laboratories (SNL) plans to conduct uncertainty analyses (UA) on the Fukushima Daiichi unit (1F1) plant with the MELCOR code. The model to be used was developed for a previous accident reconstruction investigation jointly sponsored by the US Department of Energy (DOE) and Nuclear Regulatory Commission (NRC). However, that study only examined a handful of various model inputs and boundary conditions, and the predictions yielded only fair agreement with plant data and current release estimates. The goal of this uncertainty study is to perform a focused evaluation of uncertainty in core melt progression behavior and its effect on key figures-of-merit (e.g., hydrogen production, vessel lower head failure, etc.). In preparation for the SNL Fukushima UA work, a scoping study has been completed to identify important core melt progression parameters for the uncertainty analysis. The study also lays out a preliminary UA methodology.
Directory of Open Access Journals (Sweden)
Zhenzhen Lei
2017-01-01
Full Text Available The driving pattern has an important influence on the parameter optimization of the energy management strategy (EMS for hybrid electric vehicles (HEVs. A new algorithm using simulated annealing particle swarm optimization (SA-PSO is proposed for parameter optimization of both the power system and control strategy of HEVs based on multiple driving cycles in order to realize the minimum fuel consumption without impairing the dynamic performance. Furthermore, taking the unknown of the actual driving cycle into consideration, an optimization method of the dynamic EMS based on driving pattern recognition is proposed in this paper. The simulation verifications for the optimized EMS based on multiple driving cycles and driving pattern recognition are carried out using Matlab/Simulink platform. The results show that compared with the original EMS, the former strategy reduces the fuel consumption by 4.36% and the latter one reduces the fuel consumption by 11.68%. A road test on the prototype vehicle is conducted and the effectiveness of the proposed EMS is validated by the test data.
A preliminary conceptual design study for Korean fusion DEMO reactor
Energy Technology Data Exchange (ETDEWEB)
Kim, Keeman, E-mail: kkeeman@nfri.re.kr [National Fusion Research Institute, 169-148 Gwahak-ro, Daejeon 305-806 (Korea, Republic of); Kim, Hyoung Chan; Oh, Sangjun; Lee, Young Seok; Yeom, Jun Ho; Im, Kihak; Lee, Gyung-Su [National Fusion Research Institute, 169-148 Gwahak-ro, Daejeon 305-806 (Korea, Republic of); Neilson, George; Kessel, Charles; Brown, Thomas; Titus, Peter [Princeton Plasma Physics Laboratory, Princeton University, Princeton, NJ 08543 (United States)
2013-10-15
Highlights: ► Perform a preliminary conceptual study for a steady-state Korean DEMO reactor. ► Present design guidelines and requirements of Korean DEMO reactor. ► Present a preliminary design of TF (toroidal field) and CS (central solenoid) magnet. ► Present a preliminary result of the radial build scheme of Korean DEMO reactor. -- Abstract: As the ITER is being constructed, there is a growing anticipation for an earlier realization of fusion energy, so called fast-track approach. Korean strategy for fusion energy can be regarded as a fast-track approach and one special concept discussed in this paper is a two-stage development plan. At first, a steady-state Korean DEMO Reactor (K-DEMO) is designed not only to demonstrate a net electricity generation and a self-sustained tritium cycle, but also to be used as a component test facility. Then, at its second stage, a major upgrade is carried out by replacing in-vessel components in order to show a net electric generation on the order of 300 MWe and the competitiveness in cost of electricity (COE). The major radius is designed to be just below 6.5 m, considering practical engineering feasibilities. By using high performance Nb{sub 3}Sn-based superconducting cable currently available, high magnetic field at the plasma center above 8 T can be achieved. A design concept for TF magnets and radial builds for the K-DEMO considering a vertical maintenance scheme, are presented together with preliminary design parameters.
Fuel cycle cost uncertainty from nuclear fuel cycle comparison
International Nuclear Information System (INIS)
Li, J.; McNelis, D.; Yim, M.S.
2013-01-01
This paper examined the uncertainty in fuel cycle cost (FCC) calculation by considering both model and parameter uncertainty. Four different fuel cycle options were compared in the analysis including the once-through cycle (OT), the DUPIC cycle, the MOX cycle and a closed fuel cycle with fast reactors (FR). The model uncertainty was addressed by using three different FCC modeling approaches with and without the time value of money consideration. The relative ratios of FCC in comparison to OT did not change much by using different modeling approaches. This observation was consistent with the results of the sensitivity study for the discount rate. Two different sets of data with uncertainty range of unit costs were used to address the parameter uncertainty of the FCC calculation. The sensitivity study showed that the dominating contributor to the total variance of FCC is the uranium price. In general, the FCC of OT was found to be the lowest followed by FR, MOX, and DUPIC. But depending on the uranium price, the FR cycle was found to have lower FCC over OT. The reprocessing cost was also found to have a major impact on FCC
Directory of Open Access Journals (Sweden)
Angelo La Seta
2016-05-01
Full Text Available Organic Rankine cycle (ORC power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly-loaded stages in supersonic flow regimes. Part A of this two-part paper has presented the implementation and validation of the simulation tool TURAX, which provides the optimal preliminary design of single-stage axial-flow turbines. The authors have also presented a sensitivity analysis on the decision variables affecting the turbine design. Part B of this two-part paper presents the first application of a design method where the thermodynamic cycle optimization is combined with calculations of the maximum expander performance using the mean-line design tool described in part A. The high computational cost of the turbine optimization is tackled by building a model which gives the optimal preliminary design of an axial-flow turbine as a function of the cycle conditions. This allows for estimating the optimal expander performance for each operating condition of interest. The test case is the preliminary design of an organic Rankine cycle turbogenerator to increase the overall energy efficiency of an offshore platform. For an increase in expander pressure ratio from 10 to 35, the results indicate up to 10% point reduction in expander performance. This corresponds to a relative reduction in net power output of 8.3% compared to the case when the turbine efficiency is assumed to be 80%. This work also demonstrates that this approach can support the plant designer
International Nuclear Information System (INIS)
Nawaz Amjad; Yoshikawa, Hidekazu; Ming Yang
2015-01-01
AP1000 reactor is designed for 18 month of operating cycle. The core can also be used for 16/20 months of operating cycle. This study is performed to analyze and compare the neutronic parameters of typical AP1000 reactor core for 18 month and 16/20 month alternate cycle lengths. CASMO4E and SIMULATE-3 code package is used for the analysis of initial and equilibrium cores. The key reactor physics safety parameters were analyzed including power peaking factors, core radial and axial power distribution and core reactivity feedback coefficients. Moreover, the analysis of fuel depletion, fission product buildup and burnable poison behaviour with burnup is also analyzed. Full 2-D fuel assembly model in CASMO4E and full 3-D core model in SIMULATE-3 is employed to examine core performance and safety parameters. In order to evaluate the equilibrium core neutronic parameters, the equilibrium core model is attained by performing burnup analysis from initial to equilibrium cycle, where optimized transition core design is obtained so that the power peaking factors remain within designed limits. The MTC for higher concentration of critical boron concentrations is slightly positive at lower moderator temperatures. However, it remains negative at operating temperature ranges. The radial core relative power distribution indicates that low leakage capability of initial and equilibrium cores is reduced at EOC. (author)
Preliminary analysis of public dose from CFETR gaseous tritium release
Energy Technology Data Exchange (ETDEWEB)
Nie, Baojie [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); University of Science and Technology of China, Hefei, Anhui 230027 (China); Ni, Muyi, E-mail: muyi.ni@fds.org.cn [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Lian, Chao; Jiang, Jieqiong [Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031 (China)
2015-02-15
Highlights: • Present the amounts and limit dose of tritium release to the environment for CFETR. • Perform a preliminary simulation of radiation dose for gaseous tritium release. • Key parameters about soil types, wind speed, stability class, effective release height and age were sensitivity analyzed. • Tritium release amount is recalculated consistently with dose limit in Chinese regulation for CFETR. - Abstract: To demonstrate tritium self-sufficiency and other engineering issues, the scientific conception of Chinese Fusion Engineering Test Reactor (CFETR) has been proposed in China parallel with ITER and before DEMO reactor. Tritium environmental safety for CFETR is an important issue and must be evaluated because of the huge amounts of tritium cycling in reactor. In this work, different tritium release scenarios of CFETR and dose limit regulations in China are introduced. And the public dose is preliminarily analyzed under normal and accidental events. Furthermore, after finishing the sensitivity analysis of key input parameters, the public dose is reevaluated based on extreme parameters. Finally, tritium release amount is recalculated consistently with the dose limit in Chinese regulation for CFETR, which would provide a reference for tritium system design of CFETR.
Parametric Investigation of Brayton Cycle for High Temperature Gas-Cooled Reactor
International Nuclear Information System (INIS)
Chang Oh
2004-01-01
The Idaho National Engineering and Environmental Laboratory (INEEL) is investigating a Brayton cycle efficiency improvement on a high temperature gas-cooled reactor (HTGR) as part of Generation-IV nuclear engineering research initiative. In this project, we are investigating helium Brayton cycles for the secondary side of an indirect energy conversion system. Ultimately we will investigate the improvement of the Brayton cycle using other fluids, such as supercritical carbon dioxide. Prior to the cycle improvement study, we established a number of baseline cases for the helium indirect Brayton cycle. These cases look at both single-shaft and multiple-shaft turbomachinery. The baseline cases are based on a 250 MW thermal pebble bed HTGR. The results from this study are applicable to other reactor concepts such as a very high temperature gas-cooled reactor (VHTR), fast gas-cooled reactor (FGR), supercritical water reactor (SWR), and others. In this study, we are using the HYSYS computer code for optimization of the helium Brayton cycle. Besides the HYSYS process optimization, we performed parametric study to see the effect of important parameters on the cycle efficiency. For these parametric calculations, we use a cycle efficiency model that was developed based on the Visual Basic computer language. As a part of this study we are currently investigated single-shaft vs. multiple shaft arrangement for cycle efficiency and comparison, which will be published in the next paper. The ultimate goal of this study is to use supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency to values great than that of the helium Brayton cycle. This paper includes preliminary calculations of the steady state overall Brayton cycle efficiency based on the pebble bed reactor reference design (helium used as the working fluid) and compares those results with an initial calculation of a CO2 Brayton cycle
Wang, Yuan; Zhang, Na; Yu, Gui-rui
2010-07-01
By using modified carbon-water cycle model EPPML (ecosystem productivity process model for landscape), the carbon absorption and respiration in Qianyanzhou artificial masson pine forest ecosystem in 2003 and 2004 were simulated, and the sensitivity of the model parameters was analyzed. The results showed that EPPML could effectively simulate the carbon cycle process of this ecosystem. The simulated annual values and the seasonal variations of gross primary productivity (GPP), net ecosystem productivity (NEP), and ecosystem respiration (Re) not only fitted well with the measured data, but also reflected the major impacts of extreme weather on carbon flows. The artificial masson pine forest ecosystem in Qianyanzhou was a strong carbon sink in both 2003 and 2004. Due to the coupling of high temperature and severe drought in the growth season in 2003, the carbon absorption in 2003 was lower than that in 2004. The annual NEP in 2003 and 2004 was 481.8 and 516.6 g C x m(-2) x a(-1), respectively. The key climatic factors giving important impacts on the seasonal variations of carbon cycle were solar radiation during early growth season, drought during peak growth season, and precipitation during post-peak growth season. Autotrophic respiration (Ra) and net primary productivity (NPP) had the similar seasonal variations. Soil heterotrophic respiration (Rh) was mainly affected by soil temperature at yearly scale, and by soil water content at monthly scale. During wet growth season, the higher the soil water content, the lower the Rh was; during dry growth season, the higher the precipitation during the earlier two months, the higher the Rh was. The maximum RuBP carboxylation rate at 25 degrees C (Vm25), specific leaf area (SLA), maximum leaf nitrogen content (LNm), average leaf nitrogen content (LN), and conversion coefficient of biomass to carbon (C/B) had the greatest influence on annual NEP. Different carbon cycle process could have different responses to sensitive
Air bottoming cycle, an alternative to combined cycles. Final report
Energy Technology Data Exchange (ETDEWEB)
Kaikko, J. [Royal Inst. of Techn., Stockholm (Sweden). Dept. of Energy Technology
2001-10-01
In this work, the idea of Air Bottoming Cycle (ABC) has been studied. The objectives for the work have been to establish an understanding of the concept for power and heat generation as well as to find - if possible - feasible concepts for future use in the Swedish energy system. Combined cycle in power generation is an established technology. In the conventional combined cycle, a gas turbine works as a topping cycle together with the steam (Rankine) bottoming cycle. In the ABC the steam bottoming cycle is replaced with a gas turbine (Brayton) bottoming cycle having air as a working fluid. The two gas turbines are thermally connected over a gas-to-gas heat exchanger. This concept promises savings in weight and cost, as well as operating benefits, compared to the Rankine bottoming technology. The ABC has been modelled using a heat balance program, and a parametric study for the concept optimisation as well as for off-design analysis has been performed. Performance of the ABC has been compared to other, established technologies. A preliminary economic evaluation has been made. As a result of the study, it is clarified that the Rankine bottoming cycle with steam remains superior to the ABC as regards electrical efficiency in the medium and large power scale. For small-scale applications (<10 MW{sub e}) where the thermodynamic advantage of the Rankine cycle is not dominating any longer and its economy is burdened by the heavy investment structure, the ABC becomes the better alternative for energy utilisation. A preliminary economic evaluation shows that (at energy prices autumn 2000) the ABC is at the same level as the comparable small-scale cogeneration installations. Due to high power-to-heat ratio however, higher electricity prices will favour the ABC. One interesting feature of the ABC is that about 50% of the dissipated low-value heat from the cycle is carried by clean (sterile) air at the temperature around 200 deg C. This air can be utilised for space heating or
Directory of Open Access Journals (Sweden)
Arzu Seyhan Karatepe
2013-01-01
Full Text Available Pur po se: To evaluate the effects of endogenous gonadotropic hormones (follicle-stimulating hormone, luteinizing hormone and sex steroids (progesterone, estrogen to anterior segment parameters. Ma te ri al and Met hod: Thirty healthy females who had a menstrual cycle of 28±1 day and with a mean age of 36.5±7.56 (range, 20 – 46 years were included in the study. Starting from the first day of their cycle, Pentacam Scheimpflug camera measurements were performed on the 1st, 3rd, 7th, 12th, 16th, 21st, 26th, and 28th days. The central corneal thickness, anterior chamber depth, anterior segment volume, keratometric values, anterior chamber angle value, and pupilla diameter of both eyes were evaluated. Repeated measures analysis of variance test was used for statistical analysis. Re sults: No difference that reaches statistical significance was found in the means of central corneal thickness, anterior chamber volume, keratometric values, anterior chamber angle, and pupilla diameter between the days. Mean anterior chamber depth measurement of the right eyes on the 1st day was 2.72±0.44 mm, whereas it was 2.77±0.46 mm on the 26th day. Mean anterior chamber depth measurement of the left eyes on the 1st day was 2.74±0.42 mm, whereas it was 2.80±0.43 mm on the 26th day. This increment of anterior chamber depth value from the 1st to the 26th days was found to be statistically significant (p≤0.05. Dis cus si on: Progesterone and estrogen that rise in the second half of the menstrual cycle might have a deepening effect on the anterior chamber. These findings should be further investigated with more profound studies that also evaluate the hormonal values and their correlations with anterior segment parameters. (Turk J Ophthalmol 2013; 43: 15-8
Preliminary LEU fuel cycle analyses for the Belgian BR2 reactor
International Nuclear Information System (INIS)
Deen, J.R.; Snelgrove, J.L.
1986-01-01
Fuel cycle calculations have been performed with reference HEU fuel and LEU fuel using Cd wires or boron as burnable absorbers. The 235 U content in the LEU element has increased 20% to 480g compared to the reference HEU element. The number of fuel plates has remained unchanged while the fuel meat thickness has increased to 0.76 mm from 0.51 mm. The LEU meat density is 5.1 Mg U/m 3 . The reference fuel cycle was a 31 element core operating at 56 MW with a 19.8 day cycle length and eight fresh elements loaded per cycle. Comparable fuel cycle characteristics can be achieved using the proposed LEU fuel element with either Cd wires or boron burnable absorbers. The neutron flux for E/sub n/ > 1 eV changes very little (<5%) in LEU relative to HEU cores. Thermal flux reductions are 5 to 10% in non-fueled positions, and 20 to 30% in fuel elements
Heavy water reactors on the once-through uranium cycle
International Nuclear Information System (INIS)
1978-05-01
This paper presents preliminary technical and economic data to INFCE on the once-through uranium fuel cycle for use in early comparisons of alternate nuclear systems. The denatured thorium fuel cycle is discussed in a companion paper. Information for this paper was developed under an ongoing program, and more complete reporting of the evaluation of the heavy water reactor and its fuel cycles is planned toward the end of the year
Organizational Life Cycles and Shifting Criteria of Effectiveness: Some Preliminary Evidence
Robert E. Quinn; Kim Cameron
1983-01-01
This paper discusses the relationships between stage of development in organizational life cycles and organizational effectiveness. We begin the paper by reviewing nine models of organizational life cycles that have been proposed in the literature. Each of these models identifies certain characteristics that typify organizations in different stages of development. A summary model of life cycle stages is derived that integrates each of these nine models. Next, a framework of organizational eff...
Energy Technology Data Exchange (ETDEWEB)
Chatterjee, Subhamoy; Mandal, Sudip; Banerjee, Dipankar, E-mail: dipu@iiap.res.in [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India)
2017-06-01
The Ca ii K spectroheliograms spanning over a century (1907–2007) from Kodaikanal Solar Observatory, India, have recently been digitized and calibrated. Applying a fully automated algorithm (which includes contrast enhancement and the “Watershed method”) to these data, we have identified the supergranules and calculated the associated parameters, such as scale, circularity, and fractal dimension. We have segregated the quiet and active regions and obtained the supergranule parameters separately for these two domains. In this way, we have isolated the effect of large-scale and small-scale magnetic fields on these structures and find a significantly different behavior of the supergranule parameters over solar cycles. These differences indicate intrinsic changes in the physical mechanism behind the generation and evolution of supergranules in the presence of small-scale and large-scale magnetic fields. This also highlights the need for further studies using solar dynamo theory along with magneto-convection models.
Energy Technology Data Exchange (ETDEWEB)
Ciadamidaro, L.; Madejon, P.; Cabrera, F.; Madejon, E.
2014-06-01
Aim of study: The aim of this study was to determine the effect of litter from Populus alba on chemical and biochemical properties related to the N cycle in soils with different pH values and trace element contents. We hypothesized that this litter would influence several parameters related to the N cycle and consequently to soil health. Area of study: we collected two reforested contaminated soils of different pH values (AZ pH 7.23 and DO pH 2.66) and a non-contaminated soil (RHU pH 7.19). Materials and methods: Soil samples were placed in 2,000 cm{sup 3} microcosms and were incubated for 40 weeks in controlled conditions. Each soil was mixed with its corresponding litter, and soils without litter were also tested for comparison. Ammonium (NH{sub 4}{sup 4}+-N) and nitrate (NO{sub 3}{sup -} -N) content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN), protease activity, and several chemical properties such as pH, available trace element concentrations (extracted with 0.01 M CaCl{sub 2}) were determined at different times of incubation. Main results: Values of available trace elements did not vary during the incubation and were always higher in acid soil. In neutral soils litter presence increased values of Kjeldahl-N, NO{sub 3} –-N content, potential nitrification rate (PNR), microbial biomass nitrogen (MBN) and protease activity. Presence of trace elements in neutral soils did not alter the parameters studied. However, acidic pH and high content of available trace elements strongly affected NH{sub 4}{sup +}-N and NO{sub 3}{sup -} -N, microbial biomass N and protease activity. Research highlights: Our results showed the negative effect of the acidity and trace element availability in parameters related with the N-cycle. (Author)
Directory of Open Access Journals (Sweden)
Paula Madejon
2014-04-01
Full Text Available Aim of study: The aim of this study was to determine the effect of litter from Populus alba on chemical and biochemical properties related to the N cycle in soils with different pH values and trace element contents. We hypothesized that this litter would influence several parameters related to the N cycle and consequently to soil health.Area of study: we collected two reforested contaminated soils of different pH values (AZ pH 7.23 and DO pH = 2.66 and a non-contaminated soil (RHU pH 7.19.Materials and methods: Soil samples were placed in 2,000 cm3 microcosms and were incubated for 40 weeks in controlled conditions. Each soil was mixed with its corresponding litter, and soils without litter were also tested for comparison. Ammonium (NH4+-N and nitrate (NO3–-N content, potential nitrification rate (PNR, microbial biomass nitrogen (MBN, protease activity, and several chemical properties such as pH, available trace element concentrations (extracted with 0.01 M CaCl2 were determined at different times of incubation.Main results: Values of available trace elements did not vary during the incubation and were always higher in acid soil. In neutral soils litter presence increased values of Kjeldahl-N, NO3–-N content, potential nitrification rate (PNR, microbial biomass nitrogen (MBN and protease activity. Presence of trace elements in neutral soils did not alter the parameters studied. However, acidic pH and high content of available trace elements strongly affected NH4+-N andNO3–-N, microbial biomass N and protease activity.Research highlights: Our results showed the negative effect of the acidity and trace element availability in parameters related with the N-cycle.Key words: microbial biomass N; protease activity; soil pH; N mineralization; nitrification; phytoremediation.
Air bottoming cycle, an alternative to combined cycles. Final report
Energy Technology Data Exchange (ETDEWEB)
Kaikko, J. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology
2002-02-01
In this work, the idea of Air Bottoming Cycle (ABC) has been studied. The objectives for the work have been to establish an understanding of the concept for power and heat generation as well as to find - if possible - feasible concepts for future use in the Swedish energy system. Combined cycle in power generation is an established technology. In the conventional combined cycle, a gas turbine works as a topping cycle together with the steam (Rankine) bottoming cycle. In the ABC the steam bottoming cycle is replaced with a gas turbine (Brayton) bottoming cycle having air as a working fluid. The two gas turbines are thermally connected over a gas-to-gas heat exchanger. This concept promises savings in weight and cost, as well as operating benefits, compared to the Rankine bottoming technology. The ABC has been modelled using a heat balance program, and a parametric study for the concept optimisation as well as for off-design analysis has been performed. Performance of the ABC has been compared to other, established technologies. A preliminary economic evaluation has been made. As a result of the study, it is clarified that the Rankine bottoming cycle with steam remains superior to the ABC as regards electrical efficiency in the medium and large power scale. For small-scale applications (<10 MW{sub e}) where the thermodynamic advantage of the Rankine cycle is not dominating any longer and its economy is burdened by the heavy investment structure, the ABC becomes the better alternative for energy utilisation. A preliminary economic evaluation shows that (at energy prices autumn 2000) the ABC is at the same level as the comparable small-scale cogeneration installations. Due to high power-to-heat ratio however, higher electricity prices will favour the ABC. One interesting feature of the ABC is that about 50% of the dissipated low-value heat from the cycle is carried by clean (sterile) air at the temperature around 200 deg C. This air can be utilised for space heating or
PRELIMINARY STUDY OF HEMATOLOGICAL PARAMETERS IN HERZEGOVINIAN DONKEY
Directory of Open Access Journals (Sweden)
Dunja Rukavina
2016-02-01
Full Text Available Herzegovinian donkey is a very important animal resource of Bosnia and Herzegovina. There have been no works attempted at determining the normal values of hematological parameters of Herzegovinian donkey. For this reason, the objective of the present study was to investigate some hematological parameters in Herzegovinian donkey. The research was performed on 30 apparently healthy donkeys (18 female and 12 male of ages from 1 to 20 years. Blood samples (3 ml were obtained by jugular vein puncture (vena jugularis externa in vacuum tubes with EDTA. The mean value of hematocrit was 29.19 %, hemoglobin concentration 10.6 g/dl, mean corpuscular hemoglobin concentration 36.33 g/dl, white blood cells 9.33 x109/L, granulocytes (109/L 5.45 x109/L, granulocytes (% 59.47%, lymphocyte/monocyte (109/L 3.89 x109/L, lymphocyte/monocyte (% 40.53% and platelet cells 148.97 x109/L. Parameters were determined using an automated analyzer IDEXX QBC VET AutoRead. Data were analyzed by SPSS V 15. All hematological parameters (except platelet cells were consistent with the recommended reference ranges for donkeys, and the values found in literature so far. Platelet cells values were much lower than in the literature for the other donkey breeds and the recommended reference ranges for donkeys. The slight differences found between our results and those reported in the previous works confirm the need for further studies to investigate the reference values of hematological parameters of Herzegovinian donkey. This work is a contribution to the study of hematological parameters of Herzegovinian donkey, and we expect these data to be applied to the further studies.
Directory of Open Access Journals (Sweden)
Pascalau Nelu
2017-01-01
Full Text Available Noise vibration harshness (NVH defines, as a whole, that specific field within automotive industry, that studies mostly the noise and vibrations for different assemblies (such as chassis or drivetrain – gearbox or complete vehicles, particularly cars and trucks. Gear quality parameters have been studied and it has been experienced that these parameters have an important relevance for NVH topic. Therefore, this paper introduces a case-study, as to highlight the influence of two of these parameters, profile angle deviation (fHα and tooth trace angle deviation (fHβ, on run-off cycle on test benches, for high-performance automatic transmission, designed for passenger vehicles. The demand for high accuracy is mandatory, so fine adjustments are required, as could be further observed, in order to accomplish the requirements for a lower NVH run-off rate, while the whole life-time.
Mazzoleni, S; Battini, E; Rustici, A; Stampacchia, G
2017-07-01
The aim of this study is to investigate the effects of an integrated gait rehabilitation training based on Functional Electrical Stimulation (FES)-cycling and overground robotic exoskeleton in a group of seven complete spinal cord injury patients on spasticity and patient-robot interaction. They underwent a robot-assisted rehabilitation training based on two phases: n=20 sessions of FES-cycling followed by n= 20 sessions of robot-assisted gait training based on an overground robotic exoskeleton. The following clinical outcome measures were used: Modified Ashworth Scale (MAS), Numerical Rating Scale (NRS) on spasticity, Penn Spasm Frequency Scale (PSFS), Spinal Cord Independence Measure Scale (SCIM), NRS on pain and International Spinal Cord Injury Pain Data Set (ISCI). Clinical outcome measures were assessed before (T0) after (T1) the FES-cycling training and after (T2) the powered overground gait training. The ability to walk when using exoskeleton was assessed by means of 10 Meter Walk Test (10MWT), 6 Minute Walk Test (6MWT), Timed Up and Go test (TUG), standing time, walking time and number of steps. Statistically significant changes were found on the MAS score, NRS-spasticity, 6MWT, TUG, standing time and number of steps. The preliminary results of this study show that an integrated gait rehabilitation training based on FES-cycling and overground robotic exoskeleton in complete SCI patients can provide a significant reduction of spasticity and improvements in terms of patient-robot interaction.
Energy Technology Data Exchange (ETDEWEB)
Rabi, Jose A.; Souza-Santos, Marcio L. de [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mails: jrabi@fem.unicamp.br; dss@fem.unicamp.br
2000-07-01
Modeling and simulation of fluidized-bed equipment have demonstrated their importance as a tool for design and optimization of industrial equipment. Accordingly, this work carries on an optimization study of a fluidized-bed boiler with the aid of a comprehensive mathematical simulator. The configuration data of the boiler are based on a particular Babcock and Wilcox Co. (USA) test unit. Due to their importance, the number of tubes in the bed section and the air excess are chosen as the parameters upon which the optimization study is based. On their turn, the fixed-carbon conversion factor and the boiler efficiency are chosen as two distinct optimization objectives. The results from both preliminary searches are compared. The present work is intended to be just a study on possible routes for future optimization of larger boilers. Nonetheless, the present discussion might give some insight on the equipment behavior. (author)
WWER-440 fuel cycles possibilities using improved fuel assemblies design
International Nuclear Information System (INIS)
Mikolas, P.; Svarny, J.
2008-01-01
Practically five years cycle has been achieved in the last years at NPP Dukovany. There are two principal means how it could be achieved. First, it is necessary to use fuel assemblies with higher fuel enrichment and second, to use fuel loading with very low leakage. Both these conditions are fulfilled at NPP Dukovany at this time. It is known, that the fuel cycle economy can be improved by increasing the fuel residence time in the core up to six years. There are at least two ways how this goal could be achieved. The simplest way is to increase enrichment in fuel. There exists a limit, which is 5.0 w % of 235 U. Taking into account some uncertainty, the calculation maximum is 4.95 w % of 235 U. The second way is to change fuel assembly design. There are several possibilities, which seem to be suitable from the neutron - physical point of view. The first one is higher mass content of uranium in a fuel assembly. The next possibility is to enlarge pin pitch. The last possibility is to 'omit' FA shroud. This is practically unrealistic; anyway, some other structural parts must be introduced. The basic neutron physical characteristics of these cycles for up-rated power are presented showing that the possibilities of fuel assemblies with this improved design in enlargement of fuel cycles are very promising. In the end, on the basis of neutron physical characteristics and necessary economical input parameters, a preliminary evaluation of economic contribution of proposals of advanced fuel assemblies on fuel cycle economy is presented (Authors)
Thermodynamic Analysis of Supplementary-Fired Gas Turbine Cycles
DEFF Research Database (Denmark)
Elmegaard, Brian; Henriksen, Ulrik Birk; Qvale, Einar Bjørn
2002-01-01
This paper presents an analysis of the possibilities for improving the efficiency of an indirectly biomass-fired gas turbine (IBFGT) by supplementary direct gas-firing. The supplementary firing may be based on natural gas, biogas, or pyrolysis gas. {The interest in this cycle arise from a recent...... demonstration of a two-stage gasification process through construction of several plants.} A preliminary analysis of the ideal recuperated Brayton cycle shows that for this cycle any supplementary firing will have a marginal efficiency of unity per extra unit of fuel. The same result is obtained...
Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B
DEFF Research Database (Denmark)
La Seta, Angelo; Meroni, Andrea; Andreasen, Jesper Graa
2016-01-01
Organic Rankine cycle (ORC) power systems have recently emerged as promising solutions for waste heat recovery in low- and medium-size power plants. Their performance and economic feasibility strongly depend on the expander. The design process and efficiency estimation are particularly challenging...... due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly...... is the preliminary design of an organic Rankine cycle turbogenerator to increase the overall energy efficiency of an offshore platform. For an increase in expander pressure ratio from 10 to 35, the results indicate up to 10% point reduction in expander performance. This corresponds to a relative reduction in net...
Technetium removal: preliminary flowsheet options
International Nuclear Information System (INIS)
Eager, K.M.
1995-01-01
This document presents the results of a preliminary investigation into options for preliminary flowsheets for 99Tc removal from Hanford Site tank waste. A model is created to show the path of 99Tc through pretreatment to disposal. The Tank Waste Remediation (TWRS) flowsheet (Orme 1995) is used as a baseline. Ranges of important inputs to the model are developed, such as 99Tc inventory in the tanks and important splits through the TWRS flowsheet. Several technetium removal options are discussed along with sensitivities of the removal schemes to important model parameters
Boer, H M T; Butler, S T; Stötzel, C; Te Pas, M F W; Veerkamp, R F; Woelders, H
2017-11-01
A recently developed mechanistic mathematical model of the bovine estrous cycle was parameterized to fit empirical data sets collected during one estrous cycle of 31 individual cows, with the main objective to further validate the model. The a priori criteria for validation were (1) the resulting model can simulate the measured data correctly (i.e. goodness of fit), and (2) this is achieved without needing extreme, probably non-physiological parameter values. We used a least squares optimization procedure to identify parameter configurations for the mathematical model to fit the empirical in vivo measurements of follicle and corpus luteum sizes, and the plasma concentrations of progesterone, estradiol, FSH and LH for each cow. The model was capable of accommodating normal variation in estrous cycle characteristics of individual cows. With the parameter sets estimated for the individual cows, the model behavior changed for 21 cows, with improved fit of the simulated output curves for 18 of these 21 cows. Moreover, the number of follicular waves was predicted correctly for 18 of the 25 two-wave and three-wave cows, without extreme parameter value changes. Estimation of specific parameters confirmed results of previous model simulations indicating that parameters involved in luteolytic signaling are very important for regulation of general estrous cycle characteristics, and are likely responsible for differences in estrous cycle characteristics between cows.
Directory of Open Access Journals (Sweden)
Isabel Cristina Cherici Camargo
2017-01-01
Full Text Available Topiramate (TPM is included in the newer generation of antiepileptic drugs and is known to have multiple mechanisms of action. The drug has also been used for reducing body weight. Its effect on reproductive tissues and estrous cycle deserve greater attention. Then, this study aimed to investigate possible effects of the drug on ovarian and uterine tissues, estrous cycle and some fetal parameters of non-epileptic Wistar rats. In Experiment I, females received tap water (C - Control group; n=8 or Topiramate (TPM group; 100 mg/kg; n=8, orally for 6 weeks. The estrous cycle and food consumption were monitored. Ovarian and uterine sections were examined under light microscopy. In Experiment II, pregnant rats of C and TPM groups received treatments during the pre-implantation, implantation or organogenesis period. In females of Experiment I, TPM had no effect on the food consumption, final body weight, weekly body weight and estrous cycle. Ovarian and uterine weight was similar in both groups. The kinetics of folliculogenesis was unaffected by treatment with the drug. There was a significant (p<0.05 decrease in endometrial thickness of TPM-group. In Experiment II, fetal weight was decreased (p<0.05 in all periods of TPM exposure. There was no effect of treatment on fetal external morphology. In conclusion, the findings indicate that TPM promotes discrete alterations in the uterine tissue, and causes decrease on the fetus weight after exposure in different gestational periods.
Baharudin, M. E.; Nor, A. M.; Saad, A. R. M.; Yusof, A. M.
2018-03-01
The motion of vibration-driven robots is based on an internal oscillating mass which can move without legs or wheels. The oscillation of the unbalanced mass by a motor is translated into vibration which in turn produces vertical and horizontal forces. Both vertical and horizontal oscillations are of the same frequency but the phases are shifted. The vertical forces will deflect the bristles which cause the robot to move forward. In this paper, the horizontal motion direction caused by the vertically vibrated bristle is numerically simulated by tuning the frequency of their oscillatory actuation. As a preliminary work, basic equations for a simple off-centered vibration location on the robot platform and simulation model for vibration excitement are introduced. It involves both static and dynamic vibration analysis of robots and analysis of different type of parameters. In addition, the orientation of the bristles and oscillators are also analysed. Results from the numerical integration seem to be in good agreement with those achieved from the literature. The presented numerical integration modeling can be used for designing the bristles and controlling the speed and direction of the robot.
Preliminary performance assessment for the Waste Isolation Pilot Plant, December 1992
International Nuclear Information System (INIS)
1992-01-01
This volume documents model parameters chosen as of July 1992 that were used by the Performance Assessment Department of Sandia National Laboratories in its 1992 preliminary performance assessment of the Waste Isolation Pilot Plant (WIPP). Ranges and distributions for about 300 modeling parameters in the current secondary data base are presented in tables for the geologic and engineered barriers, global materials (e.g., fluid properties), and agents that act upon the WIPP disposal system such as climate variability and human-intrusion boreholes. The 49 parameters sampled in the 1992 Preliminary Performance Assessment are given special emphasis with tables and graphics that provide insight and sources of data for each parameter
Nonrandom variability in respiratory cycle parameters of humans during stage 2 sleep.
Modarreszadeh, M; Bruce, E N; Gothe, B
1990-08-01
We analyzed breath-to-breath inspiratory time (TI), expiratory time (TE), inspiratory volume (VI), and minute ventilation (Vm) from 11 normal subjects during stage 2 sleep. The analysis consisted of 1) fitting first- and second-order autoregressive models (AR1 and AR2) and 2) obtaining the power spectra of the data by fast-Fourier transform. For the AR2 model, the only coefficients that were statistically different from zero were the average alpha 1 (a1) for TI, VI, and Vm (a1 = 0.19, 0.29, and 0.15, respectively). However, the power spectra of all parameters often exhibited peaks at low frequency (less than 0.2 cycles/breath) and/or at high frequency (greater than 0.2 cycles/breath), indicative of periodic oscillations. After accounting for the corrupting effects of added oscillations on the a1 estimates, we conclude that 1) breath-to-breath fluctuations of VI, and to a lesser extent TI and Vm, exhibit a first-order autoregressive structure such that fluctuations of each breath are positively correlated with those of immediately preceding breaths and 2) the correlated components of variability in TE are mostly due to discrete high- and/or low-frequency oscillations with no underlying autoregressive structure. We propose that the autoregressive structure of VI, TI, and Vm during spontaneous breathing in stage 2 sleep may reflect either a central neural mechanism or the effects of noise in respiratory chemical feedback loops; the presence of low-frequency oscillations, seen more often in Vm, suggests possible instability in the chemical feedback loops. Mechanisms of high-frequency periodicities, seen more often in TE, are unknown.
Nuclear fuel cycle system analysis
International Nuclear Information System (INIS)
Ko, W. I.; Kwon, E. H.; Kim, S. G.; Park, B. H.; Song, K. C.; Song, D. Y.; Lee, H. H.; Chang, H. L.; Jeong, C. J.
2012-04-01
The nuclear fuel cycle system analysis method has been designed and established for an integrated nuclear fuel cycle system assessment by analyzing various methodologies. The economics, PR(Proliferation Resistance) and environmental impact evaluation of the fuel cycle system were performed using improved DB, and finally the best fuel cycle option which is applicable in Korea was derived. In addition, this research is helped to increase the national credibility and transparency for PR with developing and fulfilling PR enhancement program. The detailed contents of the work are as follows: 1)Establish and improve the DB for nuclear fuel cycle system analysis 2)Development of the analysis model for nuclear fuel cycle 3)Preliminary study for nuclear fuel cycle analysis 4)Development of overall evaluation model of nuclear fuel cycle system 5)Overall evaluation of nuclear fuel cycle system 6)Evaluate the PR for nuclear fuel cycle system and derive the enhancement method 7)Derive and fulfill of nuclear transparency enhancement method The optimum fuel cycle option which is economical and applicable to domestic situation was derived in this research. It would be a basis for establishment of the long-term strategy for nuclear fuel cycle. This work contributes for guaranteeing the technical, economical validity of the optimal fuel cycle option. Deriving and fulfillment of the method for enhancing nuclear transparency will also contribute to renewing the ROK-U.S Atomic Energy Agreement in 2014
International Nuclear Information System (INIS)
Baltazar, O.
1978-01-01
A preliminary study of the technical characteristic of an experiment at 32 MWe power with a natural uconium, graphite-moderated, helium cooled reactor is described. The national participation and the use of reactor as an instrument for the technological development of future high temperature gas cooled reactor is considered in the choice of the reactor type. Considerations about nuclear power plants components based in extensive bibliography about similar english GCR reactor is presented. The main thermal, neutronic an static characteristic and in core management of the nuclear fuel is stablished. A simplified scheme of the secondary system and its thermodynamic performance is determined. A scheme of parameters calculation of the reactor type is defined based in the present capacity of calculation developed by Coordenadoria de Engenharia Nuclear and Centro de Processamento de Dados, IEA, Brazil [pt
Single generation cycles and delayed feedback cycles are not separate phenomena.
Pfaff, T; Brechtel, A; Drossel, B; Guill, C
2014-12-01
We study a simple model for generation cycles, which are oscillations with a period of one or a few generation times of the species. The model is formulated in terms of a single delay-differential equation for the population density of an adult stage, with recruitment to the adult stage depending on the intensity of competition during the juvenile phase. This model is a simplified version of a group of models proposed by Gurney and Nisbet, who were the first to distinguish between single-generation cycles and delayed-feedback cycles. According to these authors, the two oscillation types are caused by different mechanisms and have periods in different intervals, which are one to two generation times for single-generation cycles and two to four generation times for delayed-feedback cycles. By abolishing the strict coupling between the maturation time and the time delay between competition and its effect on the population dynamics, we find that single-generation cycles and delayed-feedback cycles occur in the same model version, with a gradual transition between the two as the model parameters are varied over a sufficiently large range. Furthermore, cycle periods are not bounded to lie within single octaves. This implies that a clear distinction between different types of generation cycles is not possible. Cycles of all periods and even chaos can be generated by varying the parameters that determine the time during which individuals from different cohorts compete with each other. This suggests that life-cycle features in the juvenile stage and during the transition to the adult stage are important determinants of the dynamics of density limited populations. Copyright © 2014 Elsevier Inc. All rights reserved.
Lika, Konstadia; Kearney, Michael R.; Kooijman, Sebastiaan A. L. M.
2011-11-01
The covariation method for estimating the parameters of the standard Dynamic Energy Budget (DEB) model provides a single-step method of accessing all the core DEB parameters from commonly available empirical data. In this study, we assess the robustness of this parameter estimation procedure and analyse the role of pseudo-data using elasticity coefficients. In particular, we compare the performance of Maximum Likelihood (ML) vs. Weighted Least Squares (WLS) approaches and find that the two approaches tend to converge in performance as the number of uni-variate data sets increases, but that WLS is more robust when data sets comprise single points (zero-variate data). The efficiency of the approach is shown to be high, and the prior parameter estimates (pseudo-data) have very little influence if the real data contain information about the parameter values. For instance, the effects of the pseudo-value for the allocation fraction κ is reduced when there is information for both growth and reproduction, that for the energy conductance is reduced when information on age at birth and puberty is given, and the effects of the pseudo-value for the maturity maintenance rate coefficient are insignificant. The estimation of some parameters (e.g., the zoom factor and the shape coefficient) requires little information, while that of others (e.g., maturity maintenance rate, puberty threshold and reproduction efficiency) require data at several food levels. The generality of the standard DEB model, in combination with the estimation of all of its parameters, allows comparison of species on the basis of parameter values. We discuss a number of preliminary patterns emerging from the present collection of parameter estimates across a wide variety of taxa. We make the observation that the estimated value of the fraction κ of mobilised reserve that is allocated to soma is far away from the value that maximises reproduction. We recognise this as the reason why two very different
A practical method to assess model sensitivity and parameter uncertainty in C cycle models
Delahaies, Sylvain; Roulstone, Ian; Nichols, Nancy
2015-04-01
The carbon cycle combines multiple spatial and temporal scales, from minutes to hours for the chemical processes occurring in plant cells to several hundred of years for the exchange between the atmosphere and the deep ocean and finally to millennia for the formation of fossil fuels. Together with our knowledge of the transformation processes involved in the carbon cycle, many Earth Observation systems are now available to help improving models and predictions using inverse modelling techniques. A generic inverse problem consists in finding a n-dimensional state vector x such that h(x) = y, for a given N-dimensional observation vector y, including random noise, and a given model h. The problem is well posed if the three following conditions hold: 1) there exists a solution, 2) the solution is unique and 3) the solution depends continuously on the input data. If at least one of these conditions is violated the problem is said ill-posed. The inverse problem is often ill-posed, a regularization method is required to replace the original problem with a well posed problem and then a solution strategy amounts to 1) constructing a solution x, 2) assessing the validity of the solution, 3) characterizing its uncertainty. The data assimilation linked ecosystem carbon (DALEC) model is a simple box model simulating the carbon budget allocation for terrestrial ecosystems. Intercomparison experiments have demonstrated the relative merit of various inverse modelling strategies (MCMC, ENKF) to estimate model parameters and initial carbon stocks for DALEC using eddy covariance measurements of net ecosystem exchange of CO2 and leaf area index observations. Most results agreed on the fact that parameters and initial stocks directly related to fast processes were best estimated with narrow confidence intervals, whereas those related to slow processes were poorly estimated with very large uncertainties. While other studies have tried to overcome this difficulty by adding complementary
International Nuclear Information System (INIS)
Kim, Kyoung Hoon; Perez-Blanco, Horacio
2015-01-01
A thermodynamic analysis of cogeneration of power and refrigeration activated by low-grade sensible energy is presented in this work. An organic Rankine cycle (ORC) for power production and a vapor compression cycle (VCC) for refrigeration using the same working fluid are linked in the analysis, including the limiting case of cold production without net electricity production. We investigate the effects of key parameters on system performance such as net power production, refrigeration, and thermal and exergy efficiencies. Characteristic indexes proportional to the cost of heat exchangers or of turbines, such as total number of transfer units (NTU tot ), size parameter (SP) and isentropic volumetric flow ratio (VFR) are also examined. Three important system parameters are selected, namely turbine inlet temperature, turbine inlet pressure, and the flow division ratio. The analysis is conducted for several different working fluids. For a few special cases, isobutane is used for a sensitivity analysis due to its relatively high efficiencies. Our results show that the system has the potential to effectively use low grade thermal sources. System performance depends both on the adopted parameters and working fluid. - Highlights: • Waste heat utilization can reduce emissions of carbon dioxide. • The ORC/VCC cycle can deliver power and/or refrigeration using waste heat. • Efficiencies and size parameters are used for cycle evaluation. • The cycle performance is studied for eight suitable refrigerants. Isobutane is used for a sensitivity analysis. • The work shows that the isobutene cycle is quite promising.
Quality assessment of water cycle parameters in REMO by radar-lidar synergy
Directory of Open Access Journals (Sweden)
B. Hennemuth
2008-01-01
Full Text Available A comparison study of water cycle parameters derived from ground-based remote-sensing instruments and from the regional model REMO is presented. Observational data sets were collected during three measuring campaigns in summer/autumn 2003 and 2004 at Richard Aßmann Observatory, Lindenberg, Germany. The remote sensing instruments which were used are differential absorption lidar, Doppler lidar, ceilometer, cloud radar, and micro rain radar for the derivation of humidity profiles, ABL height, water vapour flux profiles, cloud parameters, and rain rate. Additionally, surface latent and sensible heat flux and soil moisture were measured. Error ranges and representativity of the data are discussed. For comparisons the regional model REMO was run for all measuring periods with a horizontal resolution of 18 km and 33 vertical levels. Parameter output was every hour. The measured data were transformed to the vertical model grid and averaged in time in order to better match with gridbox model values. The comparisons show that the atmospheric boundary layer is not adequately simulated, on most days it is too shallow and too moist. This is found to be caused by a wrong partitioning of energy at the surface, particularly a too large latent heat flux. The reason is obviously an overestimation of soil moisture during drying periods by the one-layer scheme in the model. The profiles of water vapour transport within the ABL appear to be realistically simulated. The comparison of cloud cover reveals an underestimation of low-level and mid-level clouds by the model, whereas the comparison of high-level clouds is hampered by the inability of the cloud radar to see cirrus clouds above 10 km. Simulated ABL clouds apparently have a too low cloud base, and the vertical extent is underestimated. The ice water content of clouds agree in model and observation whereas the liquid water content is unsufficiently derived from cloud radar reflectivity in the present study
Thermodynamic Analysis of Supplementary-Fired Gas Turbine Cycles
DEFF Research Database (Denmark)
Elmegaard, Brian; Henriksen, Ulrik Birk; Qvale, Einar Bjørn
2003-01-01
to result in a high marginal efficiency. The paper shows that depending on the application, this is not always the case. The interest in this cycle arises from a recent demonstration of the feasibility of a two-stage gasification process through construction of several plants. The gas from this process...... could be divided into two streams, one for primary and one for supplementary firing. A preliminary analysis of the ideal, recuperated Brayton cycle shows that for this cycle any supplementary firing will have a marginal efficiency of unity per extra unit of fuel. The same result is obtained...
Space reactor preliminary mechanical design
International Nuclear Information System (INIS)
Meier, K.L.
1983-01-01
An analysis was performed on the SABRE reactor space power system to determine the effect of the number and size of heat pipes on the design parameters of the nuclear subsystem. Small numbers of thin walled heat pipes were found to give a lower subsystem mass, but excessive fuel swelling resulted. The SP-100 preliminary design uses 120 heat pipes because of acceptable fuel swelling and a minimum nuclear subsystem mass of 1875 kg. Salient features of the reactor preliminary design are: individual fuel modules, ZrO 2 block core mounts, bolted collar fuel module restraints, and a BeO central plug
Eskandari, M. A.; Mazraeshahi, H. K.; Ramesh, D.; Montazer, E.; Salami, E.; Romli, F. I.
2017-12-01
In this paper, a new method for the determination of optimum parameters of open-cycle liquid-propellant engine of launch vehicles is introduced. The parameters affecting the objective function, which is the ratio of specific impulse to gross mass of the launch vehicle, are chosen to achieve maximum specific impulse as well as minimum mass for the structure of engine, tanks, etc. The proposed algorithm uses constant integration of thrust with respect to time for launch vehicle with specific diameter and length to calculate the optimum working condition. The results by this novel algorithm are compared to those obtained from using Genetic Algorithm method and they are also validated against the results of existing launch vehicle.
International Nuclear Information System (INIS)
Nahmani, Johanne; Hodson, Mark E.; Black, Stuart
2007-01-01
Two control and eight field-contaminated, metal-polluted soils were inoculated with Eisenia fetida (Savigny, 1826). Three, 7, 14, 21, 28 and 42 days after inoculation, earthworm survival, body weight, cocoon production and hatching rate were measured. Seventeen metals were analysed in E. fetida tissue, bulk soil and soil solution. Soil organic carbon content, texture, pH and cation exchange capacity were also measured. Cocoon production and hatching rate were more sensitive to adverse conditions than survival or weight change. Soil properties other than metal concentration impacted toxicity. The most toxic soils were organic-poor (1-10 g C kg -1 ), sandy soils (c. 74% sand), with intermediate metal concentrations (e.g. 7150-13,100 mg Pb kg -1 , 2970-53,400 mg Zn kg -1 ). Significant relationships between soil properties and the life cycle parameters were determined. The best coefficients of correlation were generally found for texture, pH, Ag, Cd, Mg, Pb, Tl, and Zn both singularly and in multivariate regressions. Studies that use metal-amended artificial soils are not useful to predict toxicity of field multi-contaminated soils. - Soil pH, organic carbon content and texture can exert a greater influence on earthworm life cycle parameters than soil metal concentrations at metal-contaminated sites
Energy Technology Data Exchange (ETDEWEB)
Nahmani, Johanne [Department of Soil Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire RG6 6DW (United Kingdom)]. E-mail: nahmani@univ-metz.fr; Hodson, Mark E. [Department of Soil Science, School of Human and Environmental Sciences, University of Reading, Whiteknights, Reading, Berkshire RG6 6DW (United Kingdom)]. E-mail: m.e.hodson@reading.ac.uk; Black, Stuart [Department of Archaeology, School of Human and Environmental Sciences, Whiteknights, University of Reading, Reading RG6 6DW (United Kingdom)
2007-09-15
Two control and eight field-contaminated, metal-polluted soils were inoculated with Eisenia fetida (Savigny, 1826). Three, 7, 14, 21, 28 and 42 days after inoculation, earthworm survival, body weight, cocoon production and hatching rate were measured. Seventeen metals were analysed in E. fetida tissue, bulk soil and soil solution. Soil organic carbon content, texture, pH and cation exchange capacity were also measured. Cocoon production and hatching rate were more sensitive to adverse conditions than survival or weight change. Soil properties other than metal concentration impacted toxicity. The most toxic soils were organic-poor (1-10 g C kg{sup -1}), sandy soils (c. 74% sand), with intermediate metal concentrations (e.g. 7150-13,100 mg Pb kg{sup -1}, 2970-53,400 mg Zn kg{sup -1}). Significant relationships between soil properties and the life cycle parameters were determined. The best coefficients of correlation were generally found for texture, pH, Ag, Cd, Mg, Pb, Tl, and Zn both singularly and in multivariate regressions. Studies that use metal-amended artificial soils are not useful to predict toxicity of field multi-contaminated soils. - Soil pH, organic carbon content and texture can exert a greater influence on earthworm life cycle parameters than soil metal concentrations at metal-contaminated sites.
Preliminary Phytochemical and Physicochemical Characterization of ...
African Journals Online (AJOL)
Purpose: To carry out phytochemical and physicochemical studies on the leaves of Gynura segetum. Methods: Preliminary phytochemical and physicochemical studies using chromatographic techniques,were carried out, Parameters evaluated include ash value, loss on drying and extractive value, amongst others.
Systematic of delayed neutron parameters
International Nuclear Information System (INIS)
Isaev, S.G.; Piksaikin, V.M.
2000-01-01
The experimental studies of the energy dependence of the delayed neutron (DN) parameters for various fission systems has shown that the behaviour of a some combination of delayed neutron parameters has a similar features. On the basis of this findings the systematics of delayed neutron experimental data for thorium, uranium, plutonium and americium isotopes have been investigated with the purpose to find a correlation of DN parameters with characteristics of fissioning system as well as a correlation between the delayed neutron parameters themselves. It was presented the preliminary results which were obtained during study the physics interpretation of the results [ru
Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor
Setiadipura, T; Irwanto, D; Zuhair, Zuhair
2015-01-01
The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor ...
Cycling of conventional power plants: Technical limits and actual costs
International Nuclear Information System (INIS)
Van den Bergh, Kenneth; Delarue, Erik
2015-01-01
Highlights: • Literature reports a wide range of cycling parameters (technical and cost-related). • The impact of different cycling parameters is assessed. • The German 2013 system is studied as a case study. • Even for stringent parameters, the dynamic limit of the portfolio is not reached. • Cycling costs can be reduced with 40% when taken into account in the scheduling. - Abstract: Cycling of conventional generation units is an important source of operational flexibility in the electricity generation system. Cycling is changing the power output of conventional units by means of ramping and switching (starting up and shutting down). In the literature, a wide range of technical and cost-related cycling parameters can be found. Different studies allocate different cycling parameters to similar generation units. This paper assesses the impact of different cycling parameters allocated to a conventional generation portfolio. Both the technical limitations of power plants and all costs related to cycling are considered. The results presented in this paper follow from a unit commitment model, used for a case study based on the German 2013 system. The conventional generation portfolio has to deliver different residual load time series, corresponding to different levels of renewables penetration. The study shows, under the assumptions made, that although the dynamic limits of some units are reached, the limits of the conventional generation portfolio as a whole are not reached, even if stringent dynamic parameters are assigned to the generation portfolio and a highly variable residual load is imposed to the system. The study shows also the importance of including full cycling costs in the unit commitment scheduling. The cycling cost can be reduced by up to 40% when fully taken into account
Preliminary study of steam cycle layout and modeling for SMR application
International Nuclear Information System (INIS)
Lee, Jae Jun; Lee, Won Woong; Kwon, Jinsu; Lee, Jeong Ik
2017-01-01
Until recently, a lot of small modular reactor (SMR) concepts such as NuScale, mPower and SMART have been developed and proposed. These reactors have specific features like natural circulation, advanced passive safety system. Center for Autonomous Small Modular Reactor Research (CASMRR) has been researching Autonomous Transportable On-demand reactor Module (ATOM). ATOM has some features such as soluble boron free, passive safety system that utilizes air cooled natural circulation, automatic load following algorithm, development of fuel and structural materials and so on. As a part of the project, a simulation platform is being constructed for thermal hydraulic analysis of the system at steady and transient states and evaluation of thermal margin. Also, this platform will be used for constructing database for autonomous operation. In this paper, some processes for building the platform are introduced. The layout of steam cycle for ATOM is designed using KAIST-CCD, which is an in-house code for the cycle design. The cycle is modeled for simulating the reactor power plant system using MARS-KS. The conceptual power conversion cycle is modeled using MARS-KS. The platform is constructed with the conceptual diagram only. To improve and fill the lack of information, additional design work will be followed and the model will be updated with more details. The more accurate and specific data will be presented during the conference.
Preliminary design of smart fuel
International Nuclear Information System (INIS)
Kim, Y.; Ha, D.; Park, S.; Nahm, K.; Lee, K.; Kim, J.
2007-01-01
SMART (System-integrated Modular Advanced Reactor) is a novel light water rector with a modular, integral primary system configuration. This concept has been developing a 660 MWt by Korean Nuclear Power Industry Group with KAERI. SMART is being developed for use as an energy source for small-scale power generation and seawater desalination. Although the design of SMART is based on the current pressurized water reactor technology, new technologies such as enhanced safety, and passive safety have been applied, and system simplification and modularization, innovations in manufacturing and installation technologies have been implemented culminating in a design that has enhanced safety and economy, and is environment -friendly. In this paper described the preliminary design of the nuclear Fuel for this SMART, the design concept and the characteristics of SMART Fuel. In specially this paper describe the optimization of grid span adjustment to improve the thermal performance of the SMART Fuel as well as to improve the seismic resistance performance of the SMART Fuel, it is not easy to improve the both performance simultaneously because of design parameter of each performance inversely proportional. SMART Fuel enable to extra-long extended fuel cycle length and resistance of proliferation, enhanced safety, improved economics and reduced nuclear waste
To What Degree Thermal Cycles Affect Chalk Strength
DEFF Research Database (Denmark)
Livada, Tijana; Nermoen, Anders; Korsnes, Reidar Inger
triaxial cell experiments. For dry rock, no significant effects of temperature cycling was found on average tensile strength, however the range of the tensile failure stress is doubled for the samples exposed to 50 temperature cycles, as opposed to those to none. For water saturated cores, the temperature......Chalk reservoirs could potentially undergo destabilization as the result of repeated cold water injection into a hot reservoir during water flooding. Preliminary results of an ongoing study are presented in this paper, which compare the impact of temperature cycling on mechanical behavior on dry...... and water saturated chalk. Sixty disks of dry Kansas chalk exposed to different number of temperature cycles were tested for tensile strength using a Brazilian test. Changes in elastic properties as function of number of temperature cycles of the same chalk, but now saturated in water, were studied using...
Nonlinear solar cycle forecasting: theory and perspectives
Baranovski, A. L.; Clette, F.; Nollau, V.
2008-02-01
In this paper we develop a modern approach to solar cycle forecasting, based on the mathematical theory of nonlinear dynamics. We start from the design of a static curve fitting model for the experimental yearly sunspot number series, over a time scale of 306 years, starting from year 1700 and we establish a least-squares optimal pulse shape of a solar cycle. The cycle-to-cycle evolution of the parameters of the cycle shape displays different patterns, such as a Gleissberg cycle and a strong anomaly in the cycle evolution during the Dalton minimum. In a second step, we extract a chaotic mapping for the successive values of one of the key model parameters - the rate of the exponential growth-decrease of the solar activity during the n-th cycle. We examine piece-wise linear techniques for the approximation of the derived mapping and we provide its probabilistic analysis: calculation of the invariant distribution and autocorrelation function. We find analytical relationships for the sunspot maxima and minima, as well as their occurrence times, as functions of chaotic values of the above parameter. Based on a Lyapunov spectrum analysis of the embedded mapping, we finally establish a horizon of predictability for the method, which allows us to give the most probable forecasting of the upcoming solar cycle 24, with an expected peak height of 93±21 occurring in 2011/2012.
Role of expanders in helium liquefaction cycles: Parametric studies using Collins cycle
International Nuclear Information System (INIS)
Thomas, Rijo Jacob; Ghosh, Parthasarathi; Chowdhury, Kanchan
2011-01-01
Large scale helium liquefaction/refrigeration plant is a key subsystem of fusion devices. Performance of these plants is dependent on a number of geometric and operating parameters of its constituting components such as compressors, heat exchangers, expanders, valves, etc. Expander has been chosen as the subject matter of analyses in the present study. As the sensible cold of helium vapor is lost in liquefiers, the expanders in liquefaction cycles have to provide more refrigeration than those in refrigeration cycles. The expander parameters such as rate of mass flow, operating pressure, inlet temperature, etc. are inter-dependent, and hence, it is difficult to predict the system behavior with variation of a particular parameter. This necessitates the use of process simulators. Parametric studies have been performed on Collins helium liquefaction cycle using Aspen HYSYS. Collins cycle has all the basic characteristics of a large-scale helium liquefier and the results of this study may be extrapolated to understand the behavior of large scale helium liquefiers. The study shows that the maximum liquid production is obtained when 80% of the compressor flow is diverted through the expanders and it is equally distributed between the two expanders. The relationships between the liquid production and the isentropic efficiency of expanders are almost linear and both the higher and lower temperature expanders exhibit similar trends.
Role of expanders in helium liquefaction cycles: Parametric studies using Collins cycle
Energy Technology Data Exchange (ETDEWEB)
Thomas, Rijo Jacob, E-mail: rijojthomas@gmail.com [Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India); Ghosh, Parthasarathi; Chowdhury, Kanchan [Cryogenic Engineering Centre, Indian Institute of Technology, Kharagpur, West Bengal 721302 (India)
2011-06-15
Large scale helium liquefaction/refrigeration plant is a key subsystem of fusion devices. Performance of these plants is dependent on a number of geometric and operating parameters of its constituting components such as compressors, heat exchangers, expanders, valves, etc. Expander has been chosen as the subject matter of analyses in the present study. As the sensible cold of helium vapor is lost in liquefiers, the expanders in liquefaction cycles have to provide more refrigeration than those in refrigeration cycles. The expander parameters such as rate of mass flow, operating pressure, inlet temperature, etc. are inter-dependent, and hence, it is difficult to predict the system behavior with variation of a particular parameter. This necessitates the use of process simulators. Parametric studies have been performed on Collins helium liquefaction cycle using Aspen HYSYS. Collins cycle has all the basic characteristics of a large-scale helium liquefier and the results of this study may be extrapolated to understand the behavior of large scale helium liquefiers. The study shows that the maximum liquid production is obtained when 80% of the compressor flow is diverted through the expanders and it is equally distributed between the two expanders. The relationships between the liquid production and the isentropic efficiency of expanders are almost linear and both the higher and lower temperature expanders exhibit similar trends.
International Nuclear Information System (INIS)
Quan, B.L.
1980-01-01
A general sensitivity analysis system for analyzing the effects of uncertainity in nuclear data and reactor parameters on fuel cycle economics, resources and physics has been developed. The sensitivity analysis has been performed on various reactor systems and cycles such as the thorium cycles, plutonium cycles, CANDU reactor fuel cycles and alternate once-through LWR cycles such as the 18 month cycle. Sensitivity coefficients were generated for a variety of materials pertinent to the LWR fuel cycle using a series of fast running codes developed for this purpose and running on a local PDP-15 computer. Their relative order of importance were assessed and the reasons explaining this difference were examined. This work is a result of EPRI project in determining the data needs for the LWR industry and should be valuable in identifying areas in which data improvements are worthwhile
Alemany Fernandez, Reyes; Bartmann, Wolfgang; Buffat, Xavier; Niemi, Arto; Schulte, Daniel; Solfaroli Camillocci, Matteo; Stoel, Linda
2016-01-01
The turn-around cycle time of a collider is defined as the time spent between the end of stable beams and the start of the next stable beams period, and its calculation is of fundamental importance. On one side it is a crucial ingredient for the computation of the optimal time spent in luminosity production, which defines the integrated luminosity per fill or store. On the other side, combined with the availability and reliability of the machine, it allows to perform a detailed breakdown of the operational performance of the collider over an operational season, i.e. percentage of time in stable beams and beam in the machine with respect to down time. This paper presents a preliminary operational cycle definition for the hadron-hadron Future Circular Collider, as a base line for estimating the corresponding turn-around time. The cycle definition is based on the Large Hadron Collider (LHC) operational cycle. Two turn-around times are presented, the theoretical one and a more realistic one based on the LHC exper...
International Nuclear Information System (INIS)
Zare, V.; Hasanzadeh, M.
2016-01-01
Highlights: • A novel combined cycle is proposed for solar power tower plants. • The effects of solar subsystem and power cycle parameters are examined. • The proposed combined cycle yields exergy efficiencies of higher than 70%. • For the overall power plant exergy efficiencies of higher than 30% is achievable. - Abstract: Concentrating Solar Power (CSP) technology offers an interesting potential for future power generation and research on CSP systems of all types, particularly those with central receiver system (CRS) has been attracting a lot of attention recently. Today, these power plants cannot compete with the conventional power generation systems in terms of Levelized Cost of Electricity (LCOE) and if a competitive LCOE is to be reached, employing an efficient thermodynamic power cycle is deemed essential. In the present work, a novel combined cycle is proposed for power generation from solar power towers. The proposed system consists of a closed Brayton cycle, which uses helium as the working fluid, and two organic Rankine cycles which are employed to recover the waste heat of the Brayton cycle. The system is thermodynamically assessed from both the first and second law viewpoints. A parametric study is conducted to examine the effects of key operating parameters (including solar subsystem and power cycle parameters) on the overall power plant performance. The results indicate that exergy efficiencies of higher than 30% are achieved for the overall power plant. Also, according to the results, the power cycle proposed in this work has a better performance than the other investigated Rankine and supercritical CO_2 systems operating under similar conditions, for these types of solar power plants.
Exergy Losses in the Szewalski Binary Vapor Cycle
Directory of Open Access Journals (Sweden)
Tomasz Kowalczyk
2015-10-01
Full Text Available In this publication, we present an energy and exergy analysis of the Szewalski binary vapor cycle based on a model of a supercritical steam power plant. We used energy analysis to conduct a preliminary optimization of the cycle. Exergy loss analysis was employed to perform a comparison of heat-transfer processes, which are essential for hierarchical cycles. The Szewalski binary vapor cycle consists of a steam cycle bottomed with an organic Rankine cycle installation. This coupling has a negative influence on the thermal efficiency of the cycle. However, the primary aim of this modification is to reduce the size of the power unit by decreasing the low-pressure steam turbine cylinder and the steam condenser. The reduction of the “cold end” of the turbine is desirable from economic and technical standpoints. We present the Szewalski binary vapor cycle in addition to a mathematical model of the chosen power plant’s thermodynamic cycle. We elaborate on the procedure of the Szewalski cycle design and its optimization in order to attain an optimal size reduction of the power unit and limit exergy loss.
Preliminary investigation study of code of developed country for developing Korean fuel cycle code
International Nuclear Information System (INIS)
Jeong, Chang Joon; Ko, Won Il; Lee, Ho Hee; Cho, Dong Keun; Park, Chang Je
2012-01-01
In order to develop Korean fuel cycle code, the analyses has been performed with the fuel cycle codes which are used in advanced country. Also, recommendations were proposed for future development. The fuel cycle codes are AS FLOOWS: VISTA which has been developed by IAEA, DANESS code which developed by ANL and LISTO, and VISION developed by INL for the Advanced Fuel Cycle Initiative (AFCI) system analysis. The recommended items were proposed for software, program scheme, material flow model, isotope decay model, environmental impact analysis model, and economics analysis model. The described things will be used for development of Korean nuclear fuel cycle code in future
Energy Technology Data Exchange (ETDEWEB)
Rostron, W; Schneider, T; Thieme, M; Dreicer, M
1992-06-01
The comparison of the effects of electricity producing systems is of growing importance in decision-making processes for energy planning. This report documents the preliminary results of a project for the CEC-DG XII Radiation Protection Programme on the comparative assessment and management of the health and environmental impacts of energy systems. The work reported in this document has also been supported by EDF - Mission Environnement. In order to profit from the comparative studies already existing, some of the most important ones were surveyed. The aim of these past energy comparison studies was mainly to obtain a global measure of the risks associated with an energy cycle, with a view to ranking the various electricity production systems; but this is now recognised as merely an academic exercise, with a limited impact in decision-making. For energy planning the development of a multi-dimensional approach seems more suitable, as this allows the different types of indicators and measures needed to assess the risks of different energy cycles to be compared. From the past studies it has been seen that health indicators are generally well established, but a weakness is noted with respect to indicators of environmental impacts. This remains a difficult subject, and until such indicators are established, surrogates like concentrations in the environment will have to be used, or qualitative comparisons must suffice. This report presents a general framework allowing for consistent comparisons between different energy systems. The key issues discussed are: assessment by fuel cycle, consideration of the dimensions of time and space, the impact pathway approach for assessing risk, and coherent indicators that can be used to measure the impacts. First results are presented for four activities of the nuclear fuel cycle according to the approach developed: (1) the construction and dismantling of a 900 MWe pressurized water reactor, (2) the transportation of materials between
Energy flow and mineral cycling mechanisms
International Nuclear Information System (INIS)
Rogers, L.E.
1977-01-01
Analysis of energy flow patterns and mineral cycling mechanisms provides a first step in identifying major transport pathways away from waste management areas. A preliminary food web pattern is described using results from ongoing and completed food habit studies. Biota possessing the greatest potential for introducing radionuclides into food chains leading to man include deer, rabbits, hares, waterfowl, honeybees and upland game birds and are discussed separately
Nonlinear solar cycle forecasting: theory and perspectives
Directory of Open Access Journals (Sweden)
A. L. Baranovski
2008-02-01
Full Text Available In this paper we develop a modern approach to solar cycle forecasting, based on the mathematical theory of nonlinear dynamics. We start from the design of a static curve fitting model for the experimental yearly sunspot number series, over a time scale of 306 years, starting from year 1700 and we establish a least-squares optimal pulse shape of a solar cycle. The cycle-to-cycle evolution of the parameters of the cycle shape displays different patterns, such as a Gleissberg cycle and a strong anomaly in the cycle evolution during the Dalton minimum. In a second step, we extract a chaotic mapping for the successive values of one of the key model parameters – the rate of the exponential growth-decrease of the solar activity during the n-th cycle. We examine piece-wise linear techniques for the approximation of the derived mapping and we provide its probabilistic analysis: calculation of the invariant distribution and autocorrelation function. We find analytical relationships for the sunspot maxima and minima, as well as their occurrence times, as functions of chaotic values of the above parameter. Based on a Lyapunov spectrum analysis of the embedded mapping, we finally establish a horizon of predictability for the method, which allows us to give the most probable forecasting of the upcoming solar cycle 24, with an expected peak height of 93±21 occurring in 2011/2012.
International Nuclear Information System (INIS)
Shiotani, Hiroki; Ono, Kiyoshi; Ogawa, Takashi; Koma, Yoshikazu; Kawaguchi, Koichi
2009-01-01
A preliminary comprehensive dynamic analysis of the typical Fast Reactor (FR) deployment scenarios with JSFR and related fuel cycle facilities developed in 'FaCT: Fast Reactor Cycle Technology Development Project' was conducted. The scenarios were evaluated from some of the development targets and design goals in the FaCT project. The isotopic compositions of the nuclear fuels and wastes and the quantities of radioactive wastes (HLWs, LLWs) from Japanese nuclear fuel cycle facilities were calculated to grasp the sustainability characteristics. Regarding the long-term economics, the total cash out-flows and the average electricity generation costs to 22nd century were calculated. Cash out-flow peaks and waste generation peaks were found from 2030s to 2050s, 2090s to 2110s, and 2150s to 2170s because of the cost and wastes from decommissioning of the nuclear power plants and reprocessing plants for LWR spent fuel and the construction costs of them. Firstly, the major results of the reference case are explained combined with introduction of the function of the dynamic analysis tool (Supply Chain Management Code). The analysis is related to sustainability and economics in FaCT project development targets since they are important in the sustainability and economics evaluation. Secondly, the comparisons between the reference case and the three other option cases with their own issues of choice are explained. Those options are different breeding ratios, dual-purpose reprocessing plant, and Am-Cm recycling. As the tentative conclusions of the analyses are: the exploration of the optimal breeding ratio between B.R. =1.1 and 1.2 at the start up stage of FR is regarded as reasonable; the cost reduction of the dual purpose reprocessing plant resulted from the facility integration was confirmed though the cost estimation of the facility should be modified, it is a little bit too hasty to decide the manner of MA recycling because many issues to be considered are left at present
Coupling a Supercritical Carbon Dioxide Brayton Cycle to a Helium-Cooled Reactor.
Energy Technology Data Exchange (ETDEWEB)
Middleton, Bobby [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pasch, James Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Walker, Matthew [Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2016-01-01
This report outlines the thermodynamics of a supercritical carbon dioxide (sCO2) recompression closed Brayton cycle (RCBC) coupled to a Helium-cooled nuclear reactor. The baseline reactor design for the study is the AREVA High Temperature Gas-Cooled Reactor (HTGR). Using the AREVA HTGR nominal operating parameters, an initial thermodynamic study was performed using Sandia's deterministic RCBC analysis program. Utilizing the output of the RCBC thermodynamic analysis, preliminary values of reactor power and of Helium flow rate through the reactor were calculated in Sandia's HelCO2 code. Some research regarding materials requirements was then conducted to determine aspects of corrosion related to both Helium and to sCO2 , as well as some mechanical considerations for pressures and temperatures that will be seen by the piping and other components. This analysis resulted in a list of materials-related research items that need to be conducted in the future. A short assessment of dry heat rejection advantages of sCO2> Brayton cycles was also included. This assessment lists some items that should be investigated in the future to better understand how sCO2 Brayton cycles and nuclear can maximally contribute to optimizing the water efficiency of carbon free power generation
The use of life-cycle analysis to address energy cycle externality problems
International Nuclear Information System (INIS)
Soerensen, B.
1996-01-01
Life-cycle analysis is defined and the various impacts from energy systems to be included in such analysis are discussed. A preliminary version of a scenario for a future Danish energy systems based upon a bottom-up energy demand scenario and renewable energy sources. LCAs of wind turbine and Si solar roof-top modules are presented. The various impacts from Danish wind and building-integrated solar power generation are discussed and compared with the impacts from coal-fired power generation. The former electricity generating system looks more favorable. (author). 20 refs, 9 figs
International Nuclear Information System (INIS)
Qureshi, S.; Memon, A.G.; Abbasi, A.F.
2017-01-01
In Pakistan, the thermal efficiency of the power plants is low because of a huge share of fuel energy is dumped into the atmosphere as waste heat. The ORC (Organic Rankine Cycle) has been revealed as one of the promising technologies to recover waste heat to enhance the thermal efficiency of the power plant. In current work, ORC is proposed as a second bottoming cycle for existing CCPP (Combined Cycle Power Plant). In order to assess the efficiency of the plant, a thermodynamic model is developed in the ESS (Engineering Equation Solver) software. The developed model is used for parametric analysis to assess the effects of various operating parameters on the system performance. The analysis of results shows that the integration of ORC system with existing CCPP system enhances the overall power output in the range of 150.5-154.58 MW with 0.24-5% enhancement in the efficiency depending on the operating conditions. During the parametric analysis of ORC, it is observed that inlet pressure of the turbine shows a significant effect on the performance of the system as compared to other operating parameters. (author)
Directory of Open Access Journals (Sweden)
Mário Antônio Alves da Cunha
Full Text Available ABSTRACT: Blackberry vinegar was produced in successive acetification cycles and content of total phenolics, anthocyanins and antioxidant activity were evaluated along the production. Firstly, blackberry wine was obtained in bench-scale bioreactor, being verified 0.39 g/g ethanol yield, 1.78 g/L.h volumetric productivity and 76% efficiency. After, three successive acetification cycles were conducted efficiently in grapia barrel with average acetic acid production of 51.6 g/L, 72.2 % acetic acid yield and 0.4 g/L.h volumetric productivity. Appreciable contents of polyphenolic compounds, anthocyanins and high antioxidant activity were observed in the raw material, wine and vinegar obtained in each cycle of acetic acid transformation. Acetic acid transformation led the small reduction of antioxidant activity compared to alcoholic fermentation, but the antioxidant potential was maintained along the cycles. The content of total phenolics and anthocyanins also suffered a reduction in step of acetification.
Hydrogen Sorption Performance of Pure Magnesium during Continued Cycling
DEFF Research Database (Denmark)
Vigeholm, B.; Kjøller, John; Larsen, B.
1983-01-01
Preliminary investigations of the hydrogen absorption - desorption by commercially pure magnesium powder under continuous operation show little or no reduction in hydrogen capacity up to 70 cycles and high temperature exposure exceeding 1200 h. Absorption was studied at 260°–425°C and hydrogen...
A preliminary bending fatigue spectrum for steel monostrand cables
DEFF Research Database (Denmark)
Winkler, Jan; Fischer, Gregor; Georgakis, Christos T.
2011-01-01
This paper presents the results of the experimental study on the bending fatigue resistance of high-strength steel monostrand cables. From the conducted fatigue tests in the high-stress, low-cycle region, a preliminary bending fatigue spectrum is derived for the estimation of monostrand cable...... service life expectancy. The presented preliminary bending fatigue spectrum of high-strength monostrands is currently unavailable in the published literature. The presented results provide relevant information on the bending mechanism and fatigue characteristics of monostrand steel cables in tension...... and flexure and show that localized cable bending has a pronounced influence on the fatigue resistance of cables under dynamic excitations....
Hydrogen production at <550 C using a low temperature thermochemical cycle
International Nuclear Information System (INIS)
Lewis, M.A.; Serban, M.; Basco, J.K.
2004-01-01
A Department of Energy goal is to identify new technologies for producing hydrogen cost effectively without greenhouse gas emissions. Thermochemical cycles are one of the potential options under investigation. Thermochemical cycles consist of a series of reactions in which water is thermally decomposed and all other chemicals are recycled. Only heat and water are consumed. However, most thermochemical cycles require process heat at temperatures of 850-900 deg C. Argonne National Laboratory is developing low temperature cycles designed for lower temperature heat, 500-550 deg C, which is more readily available. For this temperature region, copper-chlorine (Cu-Cl) cycles are the most promising cycle. Several Cu-Cl cycles have been examined in the laboratory and the most promising cycle has been identified. Proof-of-principle experiments are nearly complete. A preliminary assessment of cycle efficiency is promising. Details of the experiments and efficiency calculations are discussed. (author)
Long-period variations of wind parameters in the mesopause region and the solar cycle dependence
International Nuclear Information System (INIS)
Greisiger, K.M.; Schminder, R.; Kuerschner, D.
1987-01-01
The solar cycle dependence of wind parameters below 100 km on the basis of long term continuous ionospheric drift measurements in the low frequency range is discussed. For the meridional prevailing wind no significant variation was found. The same comparison as for winter was done for summer where the previous investigations gave no correlation. Now the radar meteor wind measurement values, too, showed a significant negative correlation of the zonal prevailing wind with solar activity for the years 1976 to 1983. The ionospheric drift measurement results of Collm have the same tendency but a larger dispersion due to the lower accuracy of the harmonic analysis because of the shorter daily measuring interval in summer. Continuous wind observations in the upper mesopause region over more than 20 years revealed distinct long term variations, the origin of which cannot be explained with the present knowledge
Quantifying fluctuations in reversible enzymatic cycles and clocks
Wierenga, Harmen; ten Wolde, Pieter Rein; Becker, Nils B.
2018-04-01
Biochemical reactions are fundamentally noisy at a molecular scale. This limits the precision of reaction networks, but it also allows fluctuation measurements that may reveal the structure and dynamics of the underlying biochemical network. Here, we study nonequilibrium reaction cycles, such as the mechanochemical cycle of molecular motors, the phosphorylation cycle of circadian clock proteins, or the transition state cycle of enzymes. Fluctuations in such cycles may be measured using either of two classical definitions of the randomness parameter, which we show to be equivalent in general microscopically reversible cycles. We define a stochastic period for reversible cycles and present analytical solutions for its moments. Furthermore, we associate the two forms of the randomness parameter with the thermodynamic uncertainty relation, which sets limits on the timing precision of the cycle in terms of thermodynamic quantities. Our results should prove useful also for the study of temporal fluctuations in more general networks.
Relationships of stroke patients' gait parameters with fear of falling.
Park, Jin; Yoo, Ingyu
2014-12-01
[Purpose] The purpose of this study was to assess the correlation of gait parameters with fear of falling in stroke survivors. [Subjects] In total, 12 patients with stroke participated. [Methods] The subjects performed on a Biodex Gait Trainer 2 for 5 min to evaluate characteristic gait parameters. The kinematic gait parameters measured were gait speed, step cycle, step length, and time on each foot (step symmetry). All the subjects also completed a fall anxiety survey. [Results] Correlations between gait parameters and fear of falling scores were calculated. There was a moderate degree of correlation between fear of falling scores and the step cycle item of gait parameters. [Conclusions] According to our results, the step cycle gait parameter may be related to increased fall anxiety.
International Nuclear Information System (INIS)
Koyama, Tadafumi; Kobayashi, Hiroaki; Kinoshita, Kensuke
2009-01-01
CRIEPI has been studying the metal fuel fast reactor cycle as an outstanding alternative for the future energy sources. In this paper, development of the metal fuel cycle is reviewed in the view point of technological feasibility and material balance. Preliminary estimation of reduction of the waste burden due to introduction of the metal fuel cycle technology is also reported. (author)
Evolutionary algorithm for vehicle driving cycle generation.
Perhinschi, Mario G; Marlowe, Christopher; Tamayo, Sergio; Tu, Jun; Wayne, W Scott
2011-09-01
Modeling transit bus emissions and fuel economy requires a large amount of experimental data over wide ranges of operational conditions. Chassis dynamometer tests are typically performed using representative driving cycles defined based on vehicle instantaneous speed as sequences of "microtrips", which are intervals between consecutive vehicle stops. Overall significant parameters of the driving cycle, such as average speed, stops per mile, kinetic intensity, and others, are used as independent variables in the modeling process. Performing tests at all the necessary combinations of parameters is expensive and time consuming. In this paper, a methodology is proposed for building driving cycles at prescribed independent variable values using experimental data through the concatenation of "microtrips" isolated from a limited number of standard chassis dynamometer test cycles. The selection of the adequate "microtrips" is achieved through a customized evolutionary algorithm. The genetic representation uses microtrip definitions as genes. Specific mutation, crossover, and karyotype alteration operators have been defined. The Roulette-Wheel selection technique with elitist strategy drives the optimization process, which consists of minimizing the errors to desired overall cycle parameters. This utility is part of the Integrated Bus Information System developed at West Virginia University.
Effect of caffeine intake on critical power model parameters determined on a cycle ergometer
Directory of Open Access Journals (Sweden)
Marcus Vinicius Machado
2010-01-01
Full Text Available The aim of this study was to evaluate the effect of caffeine intake on critical power model parameters determined on a cycle ergometer. Eight male subjects participated in this study. A double-blind protocol consisting of the intake of pure caffeine (6 mg/kg or placebo (maltodextrin 60 min before testing was used. Subjects were submitted to four constant-load tests on a cycle ergometer. These tests were conducted randomly in the caffeine and placebo groups [checar] at intensities of 80, 90, 100 and 110% maximum power at a rate of 70 rpm until exhaustion to determine the critical power. As a criterion for stopping the test was adopted any rate fall without recovery by more than five seconds. The critical power and anaerobic work capacity were obtained by nonlinear regression and fitting of the curve to a hyperbolic power-time model. The Shapiro-Wilk test and paired Student t-test were used for statistical analysis. No significant differences in critical power were observed between the caffeine and placebo groups (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively. The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p< 0.01. A high association (r2 was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively. We conclude that caffeine intake did not improve critical power performance but increased anaerobic work capacity by influencing performance at loads of higher intensity and shorter duration.
Energy Technology Data Exchange (ETDEWEB)
Zhao, L.; Landi, E. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48105 (United States); Gibson, S. E., E-mail: lzh@umich.edu [NCAR/HAO, P.O. Box 3000, Boulder, CO 80307-3000 (United States)
2013-08-20
Since the unusually prolonged and weak solar minimum between solar cycles 23 and 24 (2008-2010), the sunspot number is smaller and the overall morphology of the Sun's magnetic field is more complicated (i.e., less of a dipole component and more of a tilted current sheet) compared with the same minimum and ascending phases of the previous cycle. Nearly 13 yr after the last solar maximum ({approx}2000), the monthly sunspot number is currently only at half the highest value of the past cycle's maximum, whereas the polar magnetic field of the Sun is reversing (north pole first). These circumstances make it timely to consider alternatives to the sunspot number for tracking the Sun's magnetic cycle and measuring its complexity. In this study, we introduce two novel parameters, the standard deviation (SD) of the latitude of the heliospheric current sheet (HCS) and the integrated slope (SL) of the HCS, to evaluate the complexity of the Sun's magnetic field and track the solar cycle. SD and SL are obtained from the magnetic synoptic maps calculated by a potential field source surface model. We find that SD and SL are sensitive to the complexity of the HCS: (1) they have low values when the HCS is flat at solar minimum, and high values when the HCS is highly tilted at solar maximum; (2) they respond to the topology of the HCS differently, as a higher SD value indicates that a larger part of the HCS extends to higher latitude, while a higher SL value implies that the HCS is wavier; (3) they are good indicators of magnetically anomalous cycles. Based on the comparison between SD and SL with the normalized sunspot number in the most recent four solar cycles, we find that in 2011 the solar magnetic field had attained a similar complexity as compared to the previous maxima. In addition, in the ascending phase of cycle 24, SD and SL in the northern hemisphere were on the average much greater than in the southern hemisphere, indicating a more tilted and wavier
Study on the fuel cycle cost of gas turbine high temperature reactor (GTHTR300). Contract research
Energy Technology Data Exchange (ETDEWEB)
Takei, Masanobu; Katanishi, Shoji; Nakata, Tetsuo; Kunitomi, Kazuhiko [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Oda, Takefumi; Izumiya, Toru [Nuclear Fuel Industries, Ltd., Tokyo (Japan)
2002-11-01
In the basic design of gas turbine high temperature reactor (GTHTR300), reduction of the fuel cycle cost has a large benefit of improving overall plant economy. Then, fuel cycle cost was evaluated for GTHTR300. First, of fuel fabrication for high-temperature gas cooled reactor, since there was no actual experience with a commercial scale, a preliminary design for a fuel fabrication plant with annual processing of 7.7 ton-U sufficient four GTHTR300 was performed, and fuel fabrication cost was evaluated. Second, fuel cycle cost was evaluated based on the equilibrium cycle of GTHTR300. The factors which were considered in this cost evaluation include uranium price, conversion, enrichment, fabrication, storage of spent fuel, reprocessing, and waste disposal. The fuel cycle cost of GTHTR300 was estimated at about 1.07 yen/kWh. If the back-end cost of reprocessing and waste disposal is included and assumed to be nearly equivalent to LWR, the fuel cycle cost of GTHTR300 was estimated to be about 1.31 yen/kWh. Furthermore, the effects on fuel fabrication cost by such of fuel specification parameters as enrichment, the number of fuel types, and the layer thickness were considered. Even if the enrichment varies from 10 to 20%, the number of fuel types change from 1 to 4, the 1st layer thickness of fuel changes by 30 {mu}m, or the 2nd layer to the 4th layer thickness of fuel changes by 10 {mu}m, the impact on fuel fabrication cost was evaluated to be negligible. (author)
Warm pre-stressing, preliminary experiments
International Nuclear Information System (INIS)
Hedner, G.
1984-09-01
The beneficial effect of warm pre-stressing, WPS, on apparent fracture thoughness at low temperature is well established. Tests are usually performed with constant load during the cooling part of the load cycle. In practice load variations may occur during this part. The present paper reports a preliminary study of the influence of superimposed fatigue loads. It is found that if crack propagation occurs during cooling+fatigue loading, then the maximum load during the fatigue load cycle is the preload to be used for WPS consideration. A few tests were preformed to study the effect of preload reversal. Tensile preload was followed by a compressive load and after unloading the specimens were cooled and fractured. It was found that for the high preload level used in the tests, the beneficial effect of the tensile preload could be totally annihilated by the compressive preload. (author)
Supercritical Water Reactor Cycle for Medium Power Applications
International Nuclear Information System (INIS)
BD Middleton; J Buongiorno
2007-01-01
Scoping studies for a power conversion system based on a direct-cycle supercritical water reactor have been conducted. The electric power range of interest is 5-30 MWe with a design point of 20 MWe. The overall design objective is to develop a system that has minimized physical size and performs satisfactorily over a broad range of operating conditions. The design constraints are as follows: Net cycle thermal efficiency (ge)20%; Steam turbine outlet quality (ge)90%; and Pumping power (le)2500 kW (at nominal conditions). Three basic cycle configurations were analyzed. Listed in order of increased plant complexity, they are: (1) Simple supercritical Rankine cycle; (2) All-supercritical Brayton cycle; and (3) Supercritical Rankine cycle with feedwater preheating. The sensitivity of these three configurations to various parameters, such as reactor exit temperature, reactor pressure, condenser pressure, etc., was assessed. The Thermoflex software package was used for this task. The results are as follows: (a) The simple supercritical Rankine cycle offers the greatest hardware simplification, but its high reactor temperature rise and reactor outlet temperature may pose serious problems from the viewpoint of thermal stresses, stability and materials in the core. (b) The all-supercritical Brayton cycle is not a contender, due to its poor thermal efficiency. (c) The supercritical Rankine cycle with feedwater preheating affords acceptable thermal efficiency with lower reactor temperature rise and outlet temperature. (d) The use of a moisture separator improves the performance of the supercritical Rankine cycle with feedwater preheating and allows for a further reduction of the reactor outlet temperature, thus it was selected for the next step. Preliminary engineering design of the supercritical Rankine cycle with feedwater preheating and moisture separation was performed. All major components including the turbine, feedwater heater, feedwater pump, condenser, condenser pump
Optimization of organic Rankine cycle power systems considering multistage axial turbine design
DEFF Research Database (Denmark)
Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo
2018-01-01
Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...
Optimization of organic Rankine cycle power systems considering multistage axial turbine design
DEFF Research Database (Denmark)
Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo
2017-01-01
Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...
Preliminary safety evaluation of the Gas Turbine-Modular Helium Reactor (GT-MHR)
International Nuclear Information System (INIS)
Dunn, T.D.; Lommers, L.J.; Tangirala, V.E.
1994-04-01
A qualitative comparison between the safety characteristics of the Gas Turbine-Modular Helium Reactor (GT-MHR) and those of the steam cycle shows that the two designs achieve equivalent levels of overall safety performance. This comparison is obtained by applying the scaling laws to detailed steam-cycle computations as well as the conclusions obtained from preliminary GT-MHR model simulations. The gas turbine design is predicted to be superior for some event categories, while the steam cycle design is better for others. From a safety perspective, the GT-MHR has a modest advantage for pressurized conduction cooldown events. Recent computational simulations of 102 column, 550 MW(t) GT-MHR during a depressurized conduction cooldown show that peak fuel temperatures are within the limits. The GT-MHR has a significantly lower risk due to water ingress events under operating conditions. Two additional scenarios, namely loss of load event and turbine deblading event that are specific to the GT-MHR design are discussed. Preliminary evaluation of the GT-MHR's safety characteristics indicate that the GT-MHR can be expected to satisfy or exceed its safety requirements
Features of supercritical carbon dioxide Brayton cycle coupled with reactor
International Nuclear Information System (INIS)
Duan Chengjie; Wang Jie; Yang Xiaoyong
2010-01-01
In order to obtain acceptable cycle efficiency, current helium gas turbine power cycle technology needs high cycle temperature which means that the cycle needs high core-out temperature. The technology has high requirements on reactor structure and fuel elements materials, and also on turbine manufacture. While utilizing CO 2 as cycle working fluid, it can guarantee to lower the cycle temperature and turbo machine Janume but achieve the same cycle efficiency, so as to enhance the safety and economy of reactor. According to the laws of thermodynamics, a calculation model of supercritical CO 2 power cycle was established to analyze the feature, and the decisive parameters of the cycle and also investigate the effect of each parameter on the cycle efficiency in detail were obtained. The results show that supercritical CO 2 power cycle can achieve quite satisfied efficiency at a lower cycle highest temperature than helium cycle, and CO 2 is a promising working fluid. (authors)
Are combined cycle plants being driven to zero discharge?
International Nuclear Information System (INIS)
Sinha, P.K.; Narula, R.G.; Weidinger, G.F.
1991-01-01
This paper discusses the water-related environmental issues of siting combined cycle plants, including availability of plant makeup water and wastewater discharge. The need for water treatment equipment for waste minimization, recycle, and/or zero discharge is discussed. The key water-related permit issues and preliminary design commitments are demonstrated via case histories
Preliminary Validation and Verification Plan for CAREM Reactor Protection System
International Nuclear Information System (INIS)
Fittipaldi, Ana; Maciel Felix
2000-01-01
The purpose of this paper, is to present a preliminary validation and verification plan for a particular architecture proposed for the CAREM reactor protection system with software modules (computer based system).These software modules can be either own design systems or systems based in commercial modules such as programmable logic controllers (PLC) redundant of last generation.During this study, it was seen that this plan can also be used as a validation and verification plan of commercial products (COTS, commercial off the shelf) and/or smart transmitters.The software life cycle proposed and its features are presented, and also the advantages of the preliminary validation and verification plan
Sharma, Sanjay
2017-01-01
This book provides a detailed overview of various parameters/factors involved in inventory analysis. It especially focuses on the assessment and modeling of basic inventory parameters, namely demand, procurement cost, cycle time, ordering cost, inventory carrying cost, inventory stock, stock out level, and stock out cost. In the context of economic lot size, it provides equations related to the optimum values. It also discusses why the optimum lot size and optimum total relevant cost are considered to be key decision variables, and uses numerous examples to explain each of these inventory parameters separately. Lastly, it provides detailed information on parameter estimation for different sectors/products. Written in a simple and lucid style, it offers a valuable resource for a broad readership, especially Master of Business Administration (MBA) students.
Ducrot, Virginie; Péry, Alexandre R R; Quéau, Hervé; Mons, Raphaël; Lafont, Michel; Garric, Jeanne
2007-10-01
This paper provides original collection, acclimatizing, rearing and toxicity test methods for the freshwater worm Branchiura sowerbyi, an alternative species to Tubifex tubifex for ecotoxicity evaluation of sediments. Influence of the substrate, type of food, and feeding level on individual performances was assessed in short-term tests, in order to set up optimal culture and test conditions. Low-size particles and high organic matter content favoured the growth and reproduction of B. sowerbyi. The relative contribution of sediments and fish food to the individual food intake was assessed using a foraging efficiency model based upon the dynamic energy budget theory. Individual performances were optimal when the substrate plus fish food provided the energy equivalent to 5 mg Tetramin per worm per day, which is the ad libitum food level for adults at 21 degrees C. The life-cycle of the worm was fully characterized using a life-cycle test conducted under the previously defined optimal conditions. Hatching rates were low (32%), whereas newborn and juveniles exhibited high survival (>80%) and growth (2.4 mg/day in juveniles) rates. Age at puberty was low (60 days) when compared to the maximal life span (1100 days) as predicted using a Weibull model. Adults reproduced every other month with a constant fecundity (0.16 cocoon/worm/day). The mean values of the life-cycle parameters and their variability and reproducibility among laboratory studies were discussed in order to identify relevant endpoints to be used in ecotoxicity tests. Survival, juvenile growth, and fecundity may constitute suitable test endpoints, whereas hatching rate and adult growth should not be used as endpoints in B. sowerbyi.
Optimum gas turbine cycle for combined cycle power plant
International Nuclear Information System (INIS)
Polyzakis, A.L.; Koroneos, C.; Xydis, G.
2008-01-01
The gas turbine based power plant is characterized by its relatively low capital cost compared with the steam power plant. It has environmental advantages and short construction lead time. However, conventional industrial engines have lower efficiencies, especially at part load. One of the technologies adopted nowadays for efficiency improvement is the 'combined cycle'. The combined cycle technology is now well established and offers superior efficiency to any of the competing gas turbine based systems that are likely to be available in the medium term for large scale power generation applications. This paper has as objective the optimization of a combined cycle power plant describing and comparing four different gas turbine cycles: simple cycle, intercooled cycle, reheated cycle and intercooled and reheated cycle. The proposed combined cycle plant would produce 300 MW of power (200 MW from the gas turbine and 100 MW from the steam turbine). The results showed that the reheated gas turbine is the most desirable overall, mainly because of its high turbine exhaust gas temperature and resulting high thermal efficiency of the bottoming steam cycle. The optimal gas turbine (GT) cycle will lead to a more efficient combined cycle power plant (CCPP), and this will result in great savings. The initial approach adopted is to investigate independently the four theoretically possible configurations of the gas plant. On the basis of combining these with a single pressure Rankine cycle, the optimum gas scheme is found. Once the gas turbine is selected, the next step is to investigate the impact of the steam cycle design and parameters on the overall performance of the plant, in order to choose the combined cycle offering the best fit with the objectives of the work as depicted above. Each alterative cycle was studied, aiming to find the best option from the standpoint of overall efficiency, installation and operational costs, maintainability and reliability for a combined power
Deformation Cycling of a Ti - Ni Alloy with Superelasticity Effect Applied in Cardiology
Kaputkin, D. E.; Morozova, T. V.
2014-07-01
The study concerns the effect of the conditions and of the force of loading experienced by an implanted device from a Ti - Ni alloy during its transfer to the working zone, for example, in endoscopic implantation into the coronary sinus of the greater vena cava of heart. It is shown that preliminary deformation cycling (10 - 15 cycles) stabilizes the set of mechanical properties of the alloy.
International Nuclear Information System (INIS)
Song, K. N.; Kim, Y. W.
2008-01-01
Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a nuclear hydrogen system by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950 .deg. C. Primary and secondary hot gas ducts with coaxial double tubes and are key components connecting a reactor pressure vessel and a intermediate heat exchanger for the nuclear hydrogen system. In this study, preliminary design analyses on the hot gas ducts and the intermediate heat exchanger were carried out. These preliminary design activities include a preliminary design on the geometric dimensions, a preliminary strength evaluation, thermal sizing, and an appropriate material selection
Low-decontamination approach to a proliferation-resistant fuel cycle
International Nuclear Information System (INIS)
Asquith, J.G.; Grantham, L.F.
1978-01-01
To prevent the diversion of nuclear material from power production to weapon production either by a nation or by clandestine groups within a nation, the nuclear fuel cycle must be proliferation-resistant and safeguarded. Potentially proliferation-resistant and safeguarded fuel cycles based on low-decontamination pyroreprocessing have been developed for the light water reactor (LWR), fast breeder reactor (FBR), and FBR-LWR combination. The major penalty for recycling fission products to the LWR is that fuel enrichment must be somewhat greater to overcome parasitic fission product absorption of neutrons. In the FBR, the major penalty is a slight reduction in breeding ratio due to the displacement of fertile material by fission products. Preliminary cost analysis indicates that these fuel cycles are economically competitive with fuel cycles using conventional reprocessing or those using virgin uranium if spent fuel storage costs are considered
Damage Features of Altered Rock Subjected to Drying-Wetting Cycles
Directory of Open Access Journals (Sweden)
Zhe Qin
2018-01-01
Full Text Available An abandoned open pit was used as a tailing pond for a concentrating mill, with the height of the water surface subject to cyclic fluctuation. The effects of drying and wetting cycles on the mechanical parameters of pit rock were tested. Interactions of the hydrochemical environment, due to the dissolution of tailings, and drying and wetting cycles caused degradation of mechanical properties in the rock. It was found that uniaxial compressive strength and elastic modulus decreased as the number of dry/wet cycles increased. The quantitative relationship between the mechanical parameters and the number of dry/wet cycles was indicated by an exponential function. In addition to uniaxial testing, cohesion and the internal friction angle were determined through triaxial testing. The shear strength index deteriorated under the drying and wetting cycles. The hydrochemical environment also negatively affected the mechanical parameters. Potential effects between drying and wetting cycles and slope displacement were analyzed by on-site monitoring. The results show that the displacement increased because of the drying and wetting cycles, which may lead to sudden failure of the slope.
International Nuclear Information System (INIS)
Kulkas, A; Huupponen, E; Virkkala, J; Saastamoinen, A; Rauhala, E; Tenhunen, M; Himanen, S-L
2010-01-01
The objective of the present work was to develop new computational parameters to examine the characteristics of respiratory cycle phases from the tracheal breathing sound signal during sleep. Tracheal sound data from 14 patients (10 males and 4 females) were examined. From each patient, a 10 min long section of normal and a 10 min section of flow-limited breathing during sleep were analysed. The computationally determined proportional durations of the respiratory phases were first investigated. Moreover, the phase durations and breathing sound amplitude levels were used to calculate the area under the breathing sound envelope signal during inspiration and expiration phases. An inspiratory sound index was then developed to provide the percentage of this type of area during the inspiratory phase with respect to the combined area of inspiratory and expiratory phases. The proportional duration of the inspiratory phase showed statistically significantly higher values during flow-limited breathing than during normal breathing and inspiratory pause displayed an opposite difference. The inspiratory sound index showed statistically significantly higher values during flow-limited breathing than during normal breathing. The presented novel computational parameters could contribute to the examination of sleep-disordered breathing or as a screening tool
Equipment for the measurement of non-electrical parameters
International Nuclear Information System (INIS)
Lewin, M.I.; Ewtuchow, A.N.
1977-01-01
The invention concerns equipment for the measurement of non-electrical parameters, which can be used in data processing and control equipment. The transducer converts non-electrical parameters into electrical signals. The process according to the invention is explained using the example of an inductive transducer, which is fed with alternating current. The measured parameter affects the mutual inductance of the transducer, so that the secondary voltage supplied by it is a function of the measured parameter. Amplitude measurement of this voltage by means of rectification and filtering has the disadvantage of long time constants, where the measuring period would amount to 6 to 10 cycles of the supply voltage. According to the invention the secondary voltage of the transducer is connected to an integrator during a half-cycle between two zeros, which charges a capacitor to a voltage proportional to the amplitude. An analogue-digital converter now produces a digital signal corresponding to the capacitor voltage, which is taken to the control equipment. This conversion occurs during a fraction of the second half-cycle, so that there is still time before the end of this half-cycle, so that there is still time before the end of this half-cycle to discharge the capacitor and to reproduce the initial conditions. In the next cycle the whole process is repeated, so that the measuring process only takes one cycle. In order to make the digital signal independent of the amplitude of the current fed in, this also flows through an identical transducer with constant mutual inductance, and affects the analogue-digital converter via a comparative circuit. (ORU) [de
Long-period variations of wind parameters in the mesopause region and the solar cycle dependence
International Nuclear Information System (INIS)
Greisiger, K.M.; Schminder, R.; Kuerschner, D.
1987-01-01
A solar dependence of wind parameters below 100 km was found by Sprenger and Schminder on the basis of long-term continuous ionospheric drift measurements. For winter they obtained for the prevailing wind a positive correlation with solar activity and for the amplitude of the semi-diurnal tidal wind a negative correlation. However, after the years 1973-1974 we found a significant negative correlation with solar activity with an indication of a new change after 1983. We conclude that this long-term behaviour points rather to a climatic variation with an internal atmospheric cause than to a direct solar control. Recent satellite data of the solar u.v. radiation and the upper stratospheric ozone have shown that the possible variation of the thermal tidal excitation during the solar cycle amounts to only a few per cent. This is, therefore, insufficient to account for the 40-70% variation of the tidal amplitudes. Some other possibilities of explaining this result are discussed. (author)
Chen, Jun; Ying, Guang-Guo; Liu, You-Sheng; Wei, Xiao-Dong; Liu, Shuang-Shuang; He, Liang-Ying; Yang, Yong-Qiang; Chen, Fan-Rong
2017-07-03
This study aims to investigate nitrogen removal and its relationship with the nitrogen-cycle genes and microorganisms in the horizontal subsurface flow constructed wetlands (CWs) with different design parameters. Twelve mesocosm-scale CWs with four substrates and three hydraulic loading rates were set up in the outdoor. The result showed the CWs with zeolite as substrate and HLR of 20 cm/d were selected as the best choice for the TN and NH 3 -N removal. It was found that the single-stage mesocosm-scale CWs were incapable to achieve high removals of TN and NH 3 -N due to inefficient nitrification process in the systems. This was demonstrated by the lower abundance of the nitrification genes (AOA and AOB) than the denitrification genes (nirK and nirS), and the less diverse nitrification microorganisms than the denitrification microorganisms in the CWs. The results also show that microorganism community structure including nitrogen-cycle microorganisms in the constructed wetland systems was affected by the design parameters especially the substrate type. These findings show that nitrification is a limiting factor for the nitrogen removal by CWs.
International Nuclear Information System (INIS)
Cavazzini, G.; Bari, S.; Pavesi, G.; Ardizzon, G.
2017-01-01
The present paper focuses on the thermodynamic optimization of a sub-critical ORC for heat source temperatures in the range between 80 and 150 °C. The most significant novelty of the optimization procedure is that the optimization algorithm was modified for this particular application in order to allow the swarm particles to dynamically choose the working fluid among a list of 37 candidates during their heuristic movement, by continuously and dynamically modifying the search domain of each particle iteration-by-iteration due to the different vapour saturation lines of the chosen working fluid. The significant amount of data obtained by the optimization procedure highlighted the dependency of the system efficiency on two main parameters: the Jakob number related to the optimized cycle (Ja_o_p_t) and the ratio between the critical temperature of the working fluid and the inlet heat source temperature. At closer inspection, a third new parameter Ω was identified, resulting from the combination of the previous two, whose minimization is correlated to the maximization of system efficiency. A procedure for the preliminary estimation of the optimal cycle allowing to estimate with good accuracy the Jakob number Ja_o_p_t and the corresponding value of Ω was also developed. - Highlights: • An PSO algorithm allowing for the dynamic choice of the working fluid is presented. • Thermodynamic optimizations for several heat source temperatures were carried out. • An effective parameter for choosing the best performing working fluids is presented.
Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis
Energy Technology Data Exchange (ETDEWEB)
Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-07-28
Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO2 Brayton cycle is that it enables dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately
Can FES-augmented active cycling training improve locomotion in post-acute elderly stroke patients?
Directory of Open Access Journals (Sweden)
Elisabetta Peri
2016-06-01
Full Text Available Recent studies advocated the use of active cycling coupled with functional electrical stimulation to induce neuroplasticity and enhance functional improvements in stroke adult patients. The aim of this work was to evaluate whether the benefits induced by such a treatment are superior to standard physiotherapy. A single-blinded randomized controlled trial has been performed on post-acute elderly stroke patients. Patients underwent FES-augmented cycling training combined with voluntary pedaling or standard physiotherapy. The intervention consisted of fifteen 30-minutes sessions carried out within 3 weeks. Patients were evaluated before and after training, through functional scales, gait analysis and a voluntary pedaling test. Results were compared with an age-matched healthy group. Sixteen patients completed the training. After treatment, a general improvement of all clinical scales was obtained for both groups. Only the mechanical efficiency highlighted a group effect in favor of the experimental group. Although a group effect was not found for any other cycling or gait parameters, the experimental group showed a higher percentage of change with respect to the control group (e.g. the gait velocity was improved of 35.4% and 25.4% respectively, and its variation over time was higher than minimal clinical difference for the experimental group only. This trend suggests that differences in terms of motor recovery between the two groups may be achieved increasing the training dose. In conclusion, this study, although preliminary, showed that FES-augmented active cycling training seems to be effective in improving cycling and walking ability in post-acute elderly stroke patients. A higher sample size is required to confirm results.
International Nuclear Information System (INIS)
Lyashenko, Andrey V.; Belova, Oksana; Gabdulkhakov, Azat G.; Lashkov, Alexander A.; Lisov, Alexandr V.; Leontievsky, Alexey A.; Mikhailov, Al’bert M.
2011-01-01
The purification, crystallization and preliminary X-ray structure analysis of the laccase from G. lucidum are reported. The ligninolytic enzymes of the basidiomycetes play a key role in the global carbon cycle. A characteristic property of these enzymes is their broad substrate specificity, which has led to their use in various biotechnologies, thus stimulating research into the three-dimensional structures of ligninolytic enzymes. This paper presents the purification, crystallization and preliminary X-ray analysis of the laccase from the ligninolytic basidiomycete Ganoderma lucidum
Evaluation of Haematological and Biochemical Parameters of ...
African Journals Online (AJOL)
ADOWIE PERE
Evaluation of Haematological and Biochemical Parameters of Juvenile Oreochromis niloticus after Exposure to Water Soluble Fractions of ... niloticus were evaluated. After a preliminary determination of the 96 h-LC50 of ... evaporation, dissolution, emulsion, photolysis and biodegradation which generate a water soluble.
Preliminary analysis of species partitioning in the DWPF melter. Sludge batch 7A
Energy Technology Data Exchange (ETDEWEB)
Choi, A. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith III, F. G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, D. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
2017-01-01
The work described in this report is preliminary in nature since its goal was to demonstrate the feasibility of estimating the off-gas carryover from the Defense Waste Processing Facility (DWPF) melter based on a simple mass balance using measured feed and glass pour stream (PS) compositions and time-averaged melter operating data over the duration of one canister-filling cycle. The DWPF has been in radioactive operation for over 20 years processing a wide range of high-level waste (HLW) feed compositions under varying conditions such as bubbled vs. non-bubbled and feeding vs. idling. So it is desirable to find out how the varying feed compositions and operating parameters would have impacted the off-gas entrainment. However, the DWPF melter is not equipped with off-gas sampling or monitoring capabilities, so it is not feasible to measure off-gas entrainment rates directly. The proposed method provides an indirect way of doing so.
Development of a Very High Cycle Fatigue (VHCF multiaxial testing device
Directory of Open Access Journals (Sweden)
M. Vieira
2016-07-01
Full Text Available The very high cycle region of the S-N fatigue curve has been the subject of intensive research on the last years, with special focus on axial, bending, torsional and fretting fatigue tests. Very high cycle fatigue can be achieved using ultrasonic exciters which allow for frequency testing of up to 30 kHz. Still, the multiaxial fatigue analysis is not yet developed for this type of fatigue analyses, mainly due to conceptual limitations of these testing devices. In this paper, a device designed to produce biaxial fatigue testing using a single piezoelectric axial exciter is presented, as well as the preliminary testing of this device. The device is comprised of a horn and a specimen, which are both attached to the piezoelectric exciter. The steps taken towards the final geometry of the device are presented. Preliminary experimental testing of the developed device is made using thermographic imaging, strain measurements and vibration speeds and indicates good behaviour of the tested specimen.
Evaluation and optimization of LWR fuel cycles
International Nuclear Information System (INIS)
Akbas, T.; Zabunoglu, O.; Tombakoglu, M.
2001-01-01
There are several options in the back-end of the nuclear fuel cycle. Discharge burn-up, length of interim storage period, choice of direct disposal or recycling and method of reprocessing in case of recycling affect the options and determine/define the fuel cycle scenarios. These options have been evaluated in viewpoint of some tangible (fuel cycle cost, natural uranium requirement, decay heat of high level waste, radiological ingestion and inhalation hazards) and intangible factors (technological feasibility, nonproliferation aspect, etc.). Neutronic parameters are calculated using versatile fuel depletion code ORIGEN2.1. A program is developed for calculation of cost related parameters. Analytical hierarchy process is used to transform the intangible factors into the tangible ones. Then all these tangible and intangible factors are incorporated into a form that is suitable for goal programming, which is a linear optimization technique and used to determine the optimal option among alternatives. According to the specified objective function and constraints, the optimal fuel cycle scenario is determined using GPSYS (a linear programming software) as a goal programming tool. In addition, a sensitivity analysis is performed for some selected important parameters
Thorium--uranium cycle ICF hybrid concept
International Nuclear Information System (INIS)
Frank, T.G.
1978-01-01
The results of preliminary studies of a laser-driven fusion-fission hybrid concept utilizing the 232 Th- 233 U breeding cycle are reported. Neutron multiplication in the breeding blanket is provided by a region containing 238 UO 2 and the equilibrium concentration of 239 PuO 2 . Established fission reactor technology is utilized to determine limits on operating conditions for high-temperature fuels and structures. The implications of nonproliferation policies for the operation of fusion-fission hybrid reactors are discussed
Modeling endocrine regulation of the menstrual cycle using delay differential equations.
Harris, Leona A; Selgrade, James F
2014-11-01
This article reviews an effective mathematical procedure for modeling hormonal regulation of the menstrual cycle of adult women. The procedure captures the effects of hormones secreted by several glands over multiple time scales. The specific model described here consists of 13 nonlinear, delay, differential equations with 44 parameters and correctly predicts blood levels of ovarian and pituitary hormones found in the biological literature for normally cycling women. In addition to this normal cycle, the model exhibits another stable cycle which may describe a biologically feasible "abnormal" condition such as polycystic ovarian syndrome. Model simulations illustrate how one cycle can be perturbed to the other cycle. Perturbations due to the exogenous administration of each ovarian hormone are examined. This model may be used to test the effects of hormone therapies on abnormally cycling women as well as the effects of exogenous compounds on normally cycling women. Sensitive parameters are identified and bifurcations in model behavior with respect to parameter changes are discussed. Modeling various aspects of menstrual cycle regulation should be helpful in predicting successful hormone therapies, in studying the phenomenon of cycle synchronization and in understanding many factors affecting the aging of the female reproductive endocrine system. Copyright © 2014 Elsevier Inc. All rights reserved.
Preliminary definition of the DOE/OCRWM transportation operating system: Final report
International Nuclear Information System (INIS)
Rawl, R.R.; Kline, S.C.
1988-01-01
This paper is based on the report ''Preliminary Definition of the Transportation Operations System'' and presents a summary of the preliminary definition of transportation operations activities for the cask shipment cycle, commencing with the dispatch of an empty cask, to loading and unloading of cask contents, and preparation of the empty cask for redispatch. It first presents a high-level description of the transportation cycle and then further describes each of the major activities in greater detail. For simplicity of presentation, the highway mode of transport is most often used to describe activities. The reader should keep in mind that the use of other modes will slightly alter the activities and possibly the sequences. Major activities and functions of the system are organized into a first cut of how they could be allocated to specific facilities. The reader should keep in mind that the assignment of functions and the aggregation of these into specific facilities are tasks which have yet to be performed. This paper simply presents a first look at possible groupings of the functions on a facility basis. 12 figs
International Nuclear Information System (INIS)
Miura, Tomisato; Kasai, Kosuke; Nakano, Manabu; Nakata, Akifumi; Yoshida, Mitsuaki A.; Abe, Yu; Tsushima, Eiki; Ossetrova, Natalia I.; Blakely, William F.
2014-01-01
The calyculin A-induced premature chromosome condensation (PCC) assay is a simple and useful method for assessing the cell-cycle distribution in cells, since calyculin A induces chromosome condensation in various phases of the cell cycle. In this study, a novel parameter, the cell-cycle progression index (CPI), in the PCC assay was validated as a novel bio-marker for bio-dosimetry. Peripheral blood was drawn from healthy donors after informed consent was obtained. CPI was investigated using a human peripheral blood lymphocyte (PBL) ex vivo irradiation ( 60 Co-gamma rays: ∼0.6 Gy min -1 , or X ray: 1.0 Gy min -1 ; 0-10 Gy) model. The calyculin A-induced PCC assay was performed for chromosome preparation. PCC cells were divided into the following five categories according to cell-cycle stage: non-PCC, G1-PCC, S-PCC, G2/M-PCC and M/A-PCC cells. CPI was calculated as the ratio of G2/M-PCC cells to G1-PCC cells. The PCC-stage distribution varied markedly with irradiation doses. The G1-PCC cell fraction was significantly reduced, and the G2/M-PCC cell fraction increased, in 10-Gy-irradiated PBL after 48 h of culture. CPI levels were fitted to an exponential dose-response curve with gamma-ray irradiation [y = 0.6729 + 0.3934 exp(0.5685D), r = 1.0000, p < 0.0001] and X-ray irradiation [y = -0.3743 + 0.9744 exp(0.3321D), r = 0.9999, p < 0.0001]. There were no significant individual (p = 0.853) or gender effects (p = 0.951) on the CPI in the human peripheral blood ex vivo irradiation model. Furthermore, CPI measurements are rapid (< 15 min per case). These results suggest that the CPI is a useful screening tool for the assessment of radiation doses received ranging from 0 to 10 Gy in radiation exposure early after a radiation event, especially after a mass-casualty radiological incident. (authors)
International Nuclear Information System (INIS)
Khaljani, M.; Saray, R. Khoshbakhti; Bahlouli, K.
2016-01-01
In this work, a combined power cycle which includes a HCCI (Homogenous Charge Compression Ignition) engine and two ORCs (Organic Rankine Cycles) is introduced. In the proposed cycle, the waste heats from the engine cooling water and exhaust gases are utilized to drive the ORCs. A parametric study is conducted to show the effects of decision parameters on the performance and on the total cost rate of cycle. Results of the parametric study reveal that increasing the pinch point temperature difference of evaporator and temperature of the condenser leads to reduction in both exergy efficiency and total cost rate of the bottoming cycle. There is a specific evaporator temperature where exergy efficiency is improved, but the total cost rate of the bottoming cycle is maximized. Also, a multi-objective optimization strategy is performed to achieve the best system design parameters from both thermodynamic and economic aspects. The exergy efficiency and the total cost rate of the system have been considered as objective functions. Optimization results indicate that the exergy efficiency of the cycle increases from 44.96% for the base case to 46.02%. Also, approximately1.3% reduction in the cost criteria is achieved. Results of the multi-objective optimization justify the results obtained through the parametric study and demonstrate that the design parameters of both ORCs have conflict effect on the objective functions. - Highlights: • Two Organic Rankine bottoming cycles are coupled with an HCCI Engine. • Exergetic and Exergo-economic analysis of the bottoming cycle are reported. • The system is optimized using multi-objective genetic algorithm. • Objective functions are exergy efficiency and total cost rate of the system. • The exergy efficiency of the cycle increases from 44.96% to 46.02%.
Improved Estimates of Thermodynamic Parameters
Lawson, D. D.
1982-01-01
Techniques refined for estimating heat of vaporization and other parameters from molecular structure. Using parabolic equation with three adjustable parameters, heat of vaporization can be used to estimate boiling point, and vice versa. Boiling points and vapor pressures for some nonpolar liquids were estimated by improved method and compared with previously reported values. Technique for estimating thermodynamic parameters should make it easier for engineers to choose among candidate heat-exchange fluids for thermochemical cycles.
Solar Cycle Variations of SABER CO2 and MLS H2O in the Mesosphere and Lower Thermosphere Region
Salinas, C. C. J.; Chang, L. C.; Liang, M. C.; Qian, L.; Yue, J.; Russell, J. M., III; Mlynczak, M. G.
2017-12-01
This work aims to present the solar cycle variations of SABER CO2 and MLS H2O in the Mesosphere and Lower Thermosphere region. These observations are then compared to SD-WACCM outputs of CO2 and H2O in order to understand their physical mechanisms. After which, we attempt to model their solar cycle variations using the default TIME-GCM and the TIME-GCM with MERRA reanalysis as lower-boundary conditions. Comparing the outputs of the default TIME-GCM and TIME-GCM with MERRA will give us insight into the importance of solar forcing and lower atmospheric forcing on the solar cycle variations of CO2 and H2O. The solar cycle influence in the parameters are calculated by doing a multiple linear regression with the F10.7 index. The solar cycle of SABER CO2 is reliable above 1e-2 mb and below 1e-3 mb. Preliminary results from the observations show that SABER CO2 has a stronger negative anomaly due to the solar cycle over the winter hemisphere. MLS H2O is reliable until 1e-2. Preliminary results from the observations show that MLS H2O also has a stronger negative anomaly due to the solar cycle over the winter hemisphere. Both SD-WACCM and the default TIME-GCM reproduce these stronger anomalies over the winter hemisphere. An analysis of the tendency equations in SD-WACCM and default TIME-GCM then reveal that for CO2, the stronger winter anomaly may be attributed to stronger downward transport over the winter hemisphere. For H2O, an analysis of the tendency equations in SD-WACCM reveal that the stronger winter anomaly may be attributed to both stronger downward transport and stronger photochemical loss. On the other hand, in the default TIME-GCM, the stronger winter anomaly in H2O may only be attributed to stronger downward transport. For both models, the stronger downward transport is attributed to enhanced stratospheric polar winter jet during solar maximum. Future work will determine whether setting the lower boundary conditions of TIME-GCM with MERRA will improve the match
Preliminary Design Analysis of a HGD for the NHDD Program at Korea
International Nuclear Information System (INIS)
Song, Kee Nam; Lee, H. Y.; Lee, S. B.; Kim, Y. W.
2007-01-01
Korea Atomic Energy Research Institute is in the process of carrying out a Nuclear Hydrogen Development and Demonstration (NHDD) Program by considering the indirect cycle gas cooled reactors that produce heat at temperatures in the order of 950 .deg. C. A coaxial double-tube Hot Gas Duct (HGD) is a key component connecting the reactor pressure vessel and the intermediate heat exchanger for the NHDD program. Recently, a preliminary design evaluation for the hot gas duct of the NHDD program was carried out. These preliminary design activities include a decision on the geometric dimensions, a strength evaluation, an appropriate material selection, and identifying the design code for the HGD. In this study, a preliminary strength evaluation for the HGD of the NHDD program has been undertaken based on the HTR-10 design concepts. Also, a preliminary evaluation of the creep-fatigue damage for a high temperature HGD structure has been carried out according to the draft code case for Alloy 617. Preliminary strength evaluation results for the HGD showed that the geometric dimensions of the proposed HGD would be acceptable for the design requirements
Haematological and electrocardiographic variations during menstrual cycle
International Nuclear Information System (INIS)
Rajnee, A.; Binawara, B.K.; Choudhary, S.; Chawla, V.K.; Choudhary, R.
2010-01-01
Menstruation coupled periodic bleeding from the blood vessels, at the time of shedding of the uterine mucosa has directed interest, more especially in the haematological changes during different phases of menstrual cycle. Methods: The present study was carried out on 30 healthy female medical students in the age group of 18 to 23 years with the normal menstrual cycle of 30 +- 3 days. The various haematological parameter and electrocardiography were studied on the second, eleventh, fourteenth and twenty second day of menstrual cycle. Result: The study reveals that the total leukocyte count and total platelet count significantly increased (p<0.001) around mid cycle, however total eosinophil count significantly decreased (p<0.05) during the same period. Differential leukocyte count, bleeding time, clotting time, heart rate, P-R interval and Q-T interval did not show any significant change during different phases of menstrual cycle, although some mild changes were observed. Conclusion: This study was a moderate attempt to determine regular variation in the different haematological parameters and ECG during the different phases of menstrual cycle in normal healthy females and evaluate conflicting reports on the subjects. (author)
Preliminary study on characteristics of equilibrium thorium fuel cycle of BWR
International Nuclear Information System (INIS)
Waris, A.; Kurniadi, R.; Su'ud, Z.; Permana, S.
2007-01-01
One of the main objectives behind the transuranium recycling ideas is not merely to utilize natural resource that is uranium much more efficiently, but to reduce the environmental impact of the radio-toxicity of the nuclear spent fuel. Beside uranium resource, there is thorium which has three times abundance compared to that of uranium which can be utilized as nuclear fuel. On top of that thorium is believed to have less radio-toxicity of spent fuel since its produce smaller amount of higher actinides compared to that of uranium. However, the studies on the thorium utilization in nuclear reactor in particular in light water reactors (LWR) are not performed intensively yet. Therefore, the aim of the present study is to evaluate the characteristics of thorium fuel cycle in LWR, especially boiling water reactor (BWR). To conduct the comprehensive investigations we have employed the equilibrium burnup model (1-3). The equilibrium burnup model is an alternative powerful method since its can handle all possible generated nuclides in any nuclear system. Moreover, this method is a simple time independent method. Hence the equilibrium burnup method could be very useful for evaluating and forecasting the characteristics of any nuclear fuel cycle, even the strange one, e.g. all nuclides are confined in the reactor1). We have employed 1368 nuclides in the equilibrium burnup calculation where 129 of them are heavy metals (HMs). This burnup code then is coupled with SRAC cell calculation code by using PIJ module to compose an equilibrium-cell burnup code. For cell calculation, 26 HMs, 66 fission products (FPs) and one pseudo FP have been utilized. The JENDL 3.2 library has been used in this study. References: 1. A. Waris and H. Sekimoto, 'Characteristics of several equilibrium fuel cycles of PWR', J. Nucl. Sci. Technol., 38, p.517-526, 2001 2. A. Waris, H. Sekimoto, and G. Kastchiev, Influence of Moderator-to-Fuel Volume Ratio on Pu and MA Recycling in Equilibrium Fuel Cycles of
International Nuclear Information System (INIS)
Shengjun, Zhang; Huaixin, Wang; Tao, Guo
2011-01-01
Research highlights: → We conduct the thermodynamic and economic performance comparison of the fluids in both subcritical ORC and transcritical power cycle. → We perform parameter optimization based on five indicators. → The optimum operation parameters and working fluids are not the same for different indicators. → The LEC value is used as the determining factor for fluids screening. → The transcritical power cycle with R125 as the working fluid was a cost-effective approach. - Abstract: Organic Rankine Cycle (ORC) is a promising technology for converting the low-grade energy to electricity. This paper presents an investigation on the parameter optimization and performance comparison of the fluids in subcritical ORC and transcritical power cycle in low-temperature (i.e. 80-100 o C) binary geothermal power system. The optimization procedure was conducted with a simulation program written in Matlab using five indicators: thermal efficiency, exergy efficiency, recovery efficiency, heat exchanger area per unit power output (APR) and the levelized energy cost (LEC). With the given heat source and heat sink conditions, performances of the working fluids were evaluated and compared under their optimized internal operation parameters. The optimum cycle design and the corresponding operation parameters were provided simultaneously. The results indicate that the choice of working fluid varies the objective function and the value of the optimized operation parameters are not all the same for different indicators. R123 in subcritical ORC system yields the highest thermal efficiency and exergy efficiency of 11.1% and 54.1%, respectively. Although the thermal efficiency and exergy efficiency of R125 in transcritical cycle is 46.4% and 20% lower than that of R123 in subcritical ORC, it provides 20.7% larger recovery efficiency. And the LEC value is relatively low. Moreover, 22032L petroleum is saved and 74,019 kg CO 2 is reduced per year when the LEC value is used as
Plant Characteristics of an Integrated Solid Oxide Fuel Cell Cycle and a Steam Cycle
DEFF Research Database (Denmark)
Rokni, Masoud
2010-01-01
Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. Natural gas (NG) was used as the fuel for the plant. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier...... recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization unit...
Enhanced Accident Tolerant Fuels for LWRS - A Preliminary Systems Analysis
Energy Technology Data Exchange (ETDEWEB)
Gilles Youinou; R. Sonat Sen
2013-09-01
The severe accident at Fukushima Daiichi nuclear plants illustrates the need for continuous improvements through developing and implementing technologies that contribute to safe, reliable and cost-effective operation of the nuclear fleet. Development of enhanced accident tolerant fuel contributes to this effort. These fuels, in comparison with the standard zircaloy – UO2 system currently used by the LWR industry, should be designed such that they tolerate loss of active cooling in the core for a longer time period (depending on the LWR system and accident scenario) while maintaining or improving the fuel performance during normal operations, operational transients, and design-basis events. This report presents a preliminary systems analysis related to most of these concepts. The potential impacts of these innovative LWR fuels on the front-end of the fuel cycle, on the reactor operation and on the back-end of the fuel cycle are succinctly described without having the pretension of being exhaustive. Since the design of these various concepts is still a work in progress, this analysis can only be preliminary and could be updated as the designs converge on their respective final version.
Concept for a solid-state multi-parameter sensor system for cell-culture monitoring
International Nuclear Information System (INIS)
Baecker, M.; Beging, S.; Biselli, M.; Poghossian, A.; Wang, J.; Zang, W.; Wagner, P.; Schoening, M.J.
2009-01-01
In this study, a concept for a silicon-based modular solid-state sensor system for inline multi-parameter monitoring of cell-culture fermentation processes is presented. The envisaged multi-parameter sensor system consists of two identical sensor modules and is intended for continuous quantification of up to five (bio-)chemical and physical parameters, namely, glucose and glutamine concentration, pH value, electrolyte conductivity and temperature by applying different transducer principles and/or different operation modes. Experimental results for the field-effect electrolyte-insulator-semiconductor (EIS) sterilisable pH sensor and electrolyte conductivity sensor based on interdigitated electrodes are presented. The ongoing autoclaving does not have any significant impact on the pH-sensitive properties of a Ta 2 O 5 -gate EIS sensor. Even after 30 autoclaving cycles, the pH sensors show a clear pH response and nearly linear calibration curve with a slope of 57 ± 1 mV/pH. Additional scanning electron microscopy and ellipsometric investigations do not show any visible surface degradation or changes in the thickness of the pH-sensitive Ta 2 O 5 layer. The preliminary results demonstrate the suitability of the developed EIS sensor for an inline pH measurement during a fermentation process. In addition, interdigitated electrodes of different geometries serving as electrolyte conductivity sensor have been tested for measurements in relatively high ionic-strength solutions.
Energy Technology Data Exchange (ETDEWEB)
Allegrini, E., E-mail: elia@env.dtu.dk [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Butera, S. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark); Kosson, D.S. [Vanderbilt University, Department of Civil and Environmental Engineering, Box 1831 Station B, Nashville, TN 37235 (United States); Van Zomeren, A. [Energy Research Centre of the Netherlands (ECN), Department of Environmental Risk Assessment, P.O. Box 1, 1755 ZG Petten (Netherlands); Van der Sloot, H.A. [Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk (Netherlands); Astrup, T.F. [Technical University of Denmark, Department of Environmental Engineering, Building 115, 2800 Lyngby (Denmark)
2015-04-15
Highlights: • Relevance of metal leaching in waste management system LCAs was assessed. • Toxic impacts from leaching could not be disregarded. • Uncertainty of toxicity, due to background activities, determines LCA outcomes. • Parameters such as pH and L/S affect LCA results. • Data modelling consistency and coverage within an LCA are crucial. - Abstract: Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results
Sensitivity analysis in life cycle assessment
Groen, E.A.; Heijungs, R.; Bokkers, E.A.M.; Boer, de I.J.M.
2014-01-01
Life cycle assessments require many input parameters and many of these parameters are uncertain; therefore, a sensitivity analysis is an essential part of the final interpretation. The aim of this study is to compare seven sensitivity methods applied to three types of case stud-ies. Two
Directory of Open Access Journals (Sweden)
Lihuang Luo
2016-01-01
Full Text Available A combined cycle that combines AWM cycle with a nuclear closed Brayton cycle is proposed to recover the waste heat rejected from the precooler of a nuclear closed Brayton cycle in this paper. The detailed thermodynamic and economic analyses are carried out for the combined cycle. The effects of several important parameters, such as the absorber pressure, the turbine inlet pressure, the turbine inlet temperature, the ammonia mass fraction, and the ambient temperature, are investigated. The combined cycle performance is also optimized based on a multiobjective function. Compared with the closed Brayton cycle, the optimized power output and overall efficiency of the combined cycle are higher by 2.41% and 2.43%, respectively. The optimized LEC of the combined cycle is 0.73% lower than that of the closed Brayton cycle.
International Nuclear Information System (INIS)
Mishra, R.K.; Tiwari, S.; Agarwal, R.
2008-01-01
Galactic cosmic rays are modulated at their propagation in the heliosphere by the effect of the large-scale structure of the interplanetary medium. A comparison of the variations in the cosmic ray intensity data obtained by neutron monitoring stations with those in geomagnetic disturbance, solar wind velocity (V), interplanetary magnetic field (B), and their product (V , B) near the Earth for the period 1964-2004 has been presented so as to establish a possible correlation between them. We used the hourly averaged cosmic ray counts observed with the neutron monitor in Moscow. It is noteworthy that a significant negative correlation has been observed between the interplanetary magnetic field, product (V , B) and cosmic ray intensity during the solar cycles 21 and 22. The solar wind velocity has a good positive correlation with cosmic ray intensity during solar cycle 21, whereas it shows a weak correlation during cycles 20, 22 and 23. The interplanetary magnetic field shows a weak negative correlation with cosmic rays for solar cycle 20, and a good anti-correlation for solar cycles 21-23 with the cosmic ray intensity, which, in turn, shows a good positive correlation with disturbance time index (Dst) during solar cycles 21 and 22, and a weak correlation for cycles 20 and 23. (Authors)
Development of tools to manage the operational monitoring and pre-design of the NPP-LV cycle
International Nuclear Information System (INIS)
Perusquia, R.; Arredondo S, C.; Hernandez M, J. L.; Montes T, J. L.; Castillo M, A.; Ortiz S, J. J.
2015-09-01
This paper presents the development of tools to facilitate the management so much, the operational monitoring of boiling water reactors (BWR) of the nuclear power plant of Laguna Verde (NPP-LV) through independent codes, and how to carry out the static calculations corresponding to process of optimized pre-design of the reference cycle next to current cycle. The progress and preliminary results obtained with the program SACal, developed at Instituto Nacional de Investigaciones Nucleares (ININ), central tool to achieve provide a management platform of the operational monitoring and pre-design of NPP-LV cycle are also described. The reached preliminary advances directed to get an Analysis center and automated design of fuel assembly cells are also presented, which together with centers or similar modules related with the fuel reloads form the key part to meet the targets set for the realization of a Management Platform of Nuclear Fuel of the NPP-LV. (Author)
The Design Space of the Embryonic Cell Cycle Oscillator.
Mattingly, Henry H; Sheintuch, Moshe; Shvartsman, Stanislav Y
2017-08-08
One of the main tasks in the analysis of models of biomolecular networks is to characterize the domain of the parameter space that corresponds to a specific behavior. Given the large number of parameters in most models, this is no trivial task. We use a model of the embryonic cell cycle to illustrate the approaches that can be used to characterize the domain of parameter space corresponding to limit cycle oscillations, a regime that coordinates periodic entry into and exit from mitosis. Our approach relies on geometric construction of bifurcation sets, numerical continuation, and random sampling of parameters. We delineate the multidimensional oscillatory domain and use it to quantify the robustness of periodic trajectories. Although some of our techniques explore the specific features of the chosen system, the general approach can be extended to other models of the cell cycle engine and other biomolecular networks. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.
Fishbach, L. H.
1978-01-01
The effect of turbofan engine overall pressure ratio, fan pressure ratio, and ductburner temperature rise on the engine weight and cruise fuel consumption for a mach 2.4 supersonic transport was investigated. Design point engines, optimized purely for the supersonic cruising portion of the flight where the bulk of the fuel is consumed, are considered. Based on constant thrust requirements at cruise, fuel consumption considerations would favor medium by pass ratio engines (1.5 to 1.8) of overall pressure ratio of about 16. Engine weight considerations favor low bypass ratio (0.6 or less) and low wverall pressure ratio (8). Combination of both effects results in bypass ratios of 0.6 to 0.8 and overall pressure ratio of 12 being the overall optimum.
Preliminary tests of the electrostatic plasma accelerator
Aston, G.; Acker, T.
1990-01-01
This report describes the results of a program to verify an electrostatic plasma acceleration concept and to identify those parameters most important in optimizing an Electrostatic Plasma Accelerator (EPA) thruster based upon this thrust mechanism. Preliminary performance measurements of thrust, specific impulse and efficiency were obtained using a unique plasma exhaust momentum probe. Reliable EPA thruster operation was achieved using one power supply.
The Nuclear Fuel Cycle Information System
International Nuclear Information System (INIS)
1987-02-01
The Nuclear Fuel Cycle Information System (NFCIS) is an international directory of civilian nuclear fuel cycle facilities. Its purpose is to identify existing and planned nuclear fuel cycle facilities throughout the world and to indicate their main parameters. It includes information on facilities for uranium ore processing, refining, conversion and enrichment, for fuel fabrication, away-from-reactor storage of spent fuel and reprocessing, and for the production of zirconium metal and Zircaloy tubing. NFCIS currently covers 271 facilities in 32 countries and includes 171 references
Thermo-economic analysis of combined power plants with changing economic parameters
International Nuclear Information System (INIS)
Bidini, G.; Desideri, U.; Facchini, B.
1991-01-01
A method of thermo-economic analysis for the choice of optimal thermodynamic parameters of steam bottoming cycles in combined cycle power plants is presented. By keeping the thermodynamic aspects separated from the economic aspects, this method allows designers to easily perform a sensitivity analysis of the change in the economic parameters
Preliminary study of nuclear power cogeneration system using gas turbine process
International Nuclear Information System (INIS)
Fumizawa, Motoo; Inaba, Yoshitomo; Hishida, Makoto; Ogawa, Masuro; Ogata, Kann; Yamada, Seiya.
1995-12-01
The Nuclear power generation plant (NPGP) releases smaller amount of carbon dioxide than the fossil power plant for the generation of the unit electrical power. Thus, the NPGP is expected to contribute resolving the ecological problems. It is important to investigate the nuclear power cogeneration system using gas turbine process from the view point that it is better to produce electricity in high thermal efficiency from the high temperature energy. We carried out, in the current preliminary study, the survey and selection of the candidate cycles, then conducted the evaluation of cycle efficiency, the selection of R and D items to be solved for the decision of the optimum cycle. Following this, we evaluated nuclear heat application for intermediate and low temperature level released from gas turbine process and overall efficiency of cogeneration system. As a result, it was clarified that overall efficiency of the direct regenerative cycle was the highest in low temperature region below 200degC, and that of the direct regenerative inter cooling cycle was the highest in middle and high temperature region. (author)
Preliminary study of nuclear power cogeneration system using gas turbine process
Energy Technology Data Exchange (ETDEWEB)
Fumizawa, Motoo; Inaba, Yoshitomo; Hishida, Makoto [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Ogawa, Masuro; Ogata, Kann; Yamada, Seiya
1995-12-01
The Nuclear power generation plant (NPGP) releases smaller amount of carbon dioxide than the fossil power plant for the generation of the unit electrical power. Thus, the NPGP is expected to contribute resolving the ecological problems. It is important to investigate the nuclear power cogeneration system using gas turbine process from the view point that it is better to produce electricity in high thermal efficiency from the high temperature energy. We carried out, in the current preliminary study, the survey and selection of the candidate cycles, then conducted the evaluation of cycle efficiency, the selection of R and D items to be solved for the decision of the optimum cycle. Following this, we evaluated nuclear heat application for intermediate and low temperature level released from gas turbine process and overall efficiency of cogeneration system. As a result, it was clarified that overall efficiency of the direct regenerative cycle was the highest in low temperature region below 200degC, and that of the direct regenerative inter cooling cycle was the highest in middle and high temperature region. (author).
Overview of the CANDU fuel handling system for advanced fuel cycles
International Nuclear Information System (INIS)
Koivisto, D.J.; Brown, D.R.
1997-01-01
Because of its neutron economies and on-power re-fuelling capabilities the CANDU system is ideally suited for implementing advanced fuel cycles because it can be adapted to burn these alternative fuels without major changes to the reactor. The fuel handling system is adaptable to implement advanced fuel cycles with some minor changes. Each individual advanced fuel cycle imposes some new set of special requirements on the fuel handling system that is different from the requirements usually encountered in handling the traditional natural uranium fuel. These changes are minor from an overall plant point of view but will require some interesting design and operating changes to the fuel handling system. Some preliminary conceptual design has been done on the fuel handling system in support of these fuel cycles. Some fuel handling details were studies in depth for some of the advanced fuel cycles. This paper provides an overview of the concepts and design challenges. (author)
Rotary Stirling-Cycle Engine And Generator
Chandler, Joseph A.
1990-01-01
Proposed electric-power generator comprises three motor generators coordinated by microprocessor and driven by rotary Stirling-cycle heat engine. Combination offers thermodynamic efficiency of Stirling cycle, relatively low vibration, and automatic adjustment of operating parameters to suit changing load on generator. Rotary Stirling cycle engine converts heat to power via compression and expansion of working gas between three pairs of rotary pistons on three concentric shafts in phased motion. Three motor/generators each connected to one of concentric shafts, can alternately move and be moved by pistons. Microprocessor coordinates their operation, including switching between motor and generator modes at appropriate times during each cycle.
Allegrini, E; Butera, S; Kosson, D S; Van Zomeren, A; Van der Sloot, H A; Astrup, T F
2015-04-01
Residues from industrial processes and waste management systems (WMSs) have been increasingly reutilised, leading to landfilling rate reductions and the optimisation of mineral resource utilisation in society. Life cycle assessment (LCA) is a holistic methodology allowing for the analysis of systems and products and can be applied to waste management systems to identify environmental benefits and critical aspects thereof. From an LCA perspective, residue utilisation provides benefits such as avoiding the production and depletion of primary materials, but it can lead to environmental burdens, due to the potential leaching of toxic substances. In waste LCA studies where residue utilisation is included, leaching has generally been neglected. In this study, municipal solid waste incineration bottom ash (MSWI BA) was used as a case study into three LCA scenarios having different system boundaries. The importance of data quality and parameter selection in the overall LCA results was evaluated, and an innovative method to assess metal transport into the environment was applied, in order to determine emissions to the soil and water compartments for use in an LCA. It was found that toxic impacts as a result of leaching were dominant in systems including only MSWI BA utilisation, while leaching appeared negligible in larger scenarios including the entire waste system. However, leaching could not be disregarded a priori, due to large uncertainties characterising other activities in the scenario (e.g. electricity production). Based on the analysis of relevant parameters relative to leaching, and on general results of the study, recommendations are provided regarding the use of leaching data in LCA studies. Copyright © 2014 Elsevier Ltd. All rights reserved.
Relation between Feynman Cycles and Off-Diagonal Long-Range Order
International Nuclear Information System (INIS)
Ueltschi, Daniel
2006-01-01
The usual order parameter for Bose-Einstein condensation involves the off-diagonal correlation function of Penrose and Onsager, but an alternative is Feynman's notion of infinite cycles. We present a formula that relates both order parameters. We discuss its validity with the help of rigorous results and heuristic arguments. The conclusion is that infinite cycles do not always represent the Bose condensate
Power generation costs for alternate reactor fuel cycles
International Nuclear Information System (INIS)
Smolen, G.R.; Delene, J.G.
1980-09-01
The total electric generating costs at the power plant busbar are estimated for various nuclear reactor fuel cycles which may be considered for power generation in the future. The reactor systems include pressurized water reactors (PWR), heavy-water reactors (HWR), high-temperature gas cooled reactors (HTGR), liquid-metal fast breeder reactors (LMFBR), light-water pre-breeder and breeder reactors (LWPR, LWBR), and a fast mixed spectrum reactor (FMSR). Fuel cycles include once-through, uranium-only recycle, and full recycle of the uranium and plutonium in the spent fuel assemblies. The U 3 O 8 price for economic transition from once-through LWR fuel cycles to both PWR recycle and LMFBR systems is estimated. Electric power generation costs were determined both for a reference set of unit cost parameters and for a range of uncertainty in these parameters. In addition, cost sensitivity parameters are provided so that independent estimations can be made for alternate cost assumptions
Parametric analysis and optimization for a combined power and refrigeration cycle
International Nuclear Information System (INIS)
Wang Jiangfeng; Dai Yiping; Gao Lin
2008-01-01
A combined power and refrigeration cycle is proposed, which combines the Rankine cycle and the absorption refrigeration cycle. This combined cycle uses a binary ammonia-water mixture as the working fluid and produces both power output and refrigeration output simultaneously with only one heat source. A parametric analysis is conducted to evaluate the effects of thermodynamic parameters on the performance of the combined cycle. It is shown that heat source temperature, environment temperature, refrigeration temperature, turbine inlet pressure, turbine inlet temperature, and basic solution ammonia concentration have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. A parameter optimization is achieved by means of genetic algorithm to reach the maximum exergy efficiency. The optimized exergy efficiency is 43.06% under the given condition
DEFF Research Database (Denmark)
Niero, Monia; Di Felice, F.; Ren, J.
2014-01-01
LCA methodology is time and resource consuming particularly when it comes to data collection and handling, therefore companies, particularly Small and Medium Enterprises (SMEs), are inclined to use streamlined approaches to shorten the resource-consuming life cycle inventory (LCI) phase. An effec......LCA methodology is time and resource consuming particularly when it comes to data collection and handling, therefore companies, particularly Small and Medium Enterprises (SMEs), are inclined to use streamlined approaches to shorten the resource-consuming life cycle inventory (LCI) phase...... study of a SME in the wooden pallet sector, investigating to what extent the use of parametric LCI models can be beneficial both in evaluating the environmental impacts of similar products and in providing a preliminary assessment of the potential environmental impacts of new products. We developed...... an LCI parametric model describing the LCI of a range of wooden pallets and tested its effectiveness with a reference product, namely a non-reversible pallet with four-way blocks. The identified parameters refer to the technical characteristics of the product system, e.g. the number and dimension...
Perform Thermodynamics Measurements on Fuel Cycle Case Study Systems
Energy Technology Data Exchange (ETDEWEB)
Martin, Leigh R. [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2014-09-01
This document was prepared to meet FCR&D level 3 milestone M3FT-14IN0304022, “Perform Thermodynamics Measurements on Fuel Cycle Case Study Systems.” This work was carried out under the auspices of the Thermodynamics and Kinetics FCR&D work package. This document reports preliminary work in support of determining the thermodynamic parameters for the ALSEP process. The ALSEP process is a mixed extractant system comprised of a cation exchanger 2-ethylhexyl-phosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) and a neutral solvating extractant N,N,N’,N’-tetraoctyldiglycolamide (TODGA). The extractant combination produces complex organic phase chemistry that is challenging for traditional measurement techniques. To neutralize the complexity, temperature dependent solvent extraction experiments were conducted with neat TODGA and scaled down concentrations of the ALSEP formulation to determine the enthalpies of extraction for the two conditions. A full set of thermodynamic data for Eu, Am, and Cm extraction by TODGA from 3.0 M HNO3 is reported. These data are compared to previous extraction results from a 1.0 M HNO3 aqueous medium, and a short discussion of the mixed HEH[EHP]/TODGA system results is offered.
International Nuclear Information System (INIS)
Chen, Xiangjie; Worall, Mark; Omer, Siddig; Su, Yuehong; Riffat, Saffa
2013-01-01
Highlights: ► Waste heat from vehicle exhausted gas was used as heat source for ejector. ► Ejector acts as the main interface between ejector and CO 2 VC sub-system. ► The effect of sub-cooling was analyzed. ► COP of ejector cooling system was measured between 0.2 and 0.5 during experiments. ► Enhanced ejector and vapour compression system. -- Abstract: This paper presents theoretical investigations into a hybrid ejector and CO 2 vapour compression (VC) system for road transport cooling. The purpose is to utilise the waste heat from exhaust gas and the VC sub-system to drive the ejector system, whose cooling effect will be employed to subcool the VC sub-system. Exploitation of the energy consumption ratio between ejector sub-system and CO 2 VC sub-system indicated that the more energy obtained from exhausted gas, the better system performance could be achieved for CO 2 VC sub-system, and hence higher cooling capacity of the VC sub-system at the same compression power. Thermodynamic simulations of two sub-systems and the hybrid system were presented. The results indicated that, at boiler temperature of 120 °C, evaporator temperature of 10 °C, a COP of 0.584 was achieved for hybrid system, with 22% improvement over a single ejector cycle. Preliminary experimental studies were carried out on a single ejector cycle, with boiler temperatures between 115 °C and 130 °C, and evaporator temperatures between 5 °C and 10 °C. The effects of various operation conditions on the overall ejector operation were coherently analysed. The COP of the ejector sub-system from experimental results was approximately 85% compared with simulation results, which showed a good agreement between theoretical analysis and experimental results.
Energy Technology Data Exchange (ETDEWEB)
Bae, Seong Jun; Lee, Won Woong; Jeong, Yong Hoon; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of); Yoon, Ho Joon [KUSTAR, Abu Dhabi (United Arab Emirates)
2015-10-15
This study was conducted to explore the capabilities of the S-CO{sub 2} Brayton cycle for a cogeneration system for APR-1400 application. Three concepts of the S-CO{sub 2} simple recuperated co-generation cycle were designed. A supercritical CO{sub 2} (S-CO{sub 2}) Brayton cycle is recently receiving significant attention as a promising power conversion system in wide range of energy applications due to its high efficiency and compact footprint. The main reason why the S-CO{sub 2} Brayton cycle has these advantages is that the compressor operates near the critical point of CO{sub 2} (30.98 .deg. C, 7.38MPa) to reduce the compression work significantly compared to the other Brayton cycles. In this study, the concept of replacing the entire steam cycle of APR-1400 with the S-CO{sub 2} Brayton cycle is evaluated. The power generation purpose S-CO{sub 2} Brayton cycles are redesigned to generate power and provide heat to the desalination system at the same time. The performance of these newly suggested cycles are evaluated in this paper. The target was to deliver 147MW heat to the desalination process. The thermal efficiencies of the three concepts are not significantly different, but the 3{sup rd} concept is relatively simpler than other cycles because only an additional heat exchanger is required. Although the 2{sup nd} concept is relatively complicated in comparison to other concepts, the temperatures at the inlet and outlet of the DHX are higher than that of the others. As shown in the results, the S-CO{sub 2} Brayton cycles are not easy to outperform the steam cycle with very simple layout and general design points under APR-1400 operating condition. However, this study shows that the S-CO{sub 2} Brayton cycles can be designed as a co-generation cycle while producing the target desalination heat with a simple configuration. In addition, it was also found that the S-CO{sub 2} Brayton cycle can achieve higher cycle thermal efficiency than the steam power cycle under
Burnup effect on nuclear fuel cycle cost using an equilibrium model
International Nuclear Information System (INIS)
Youn, S. R.; Kim, S. K.; Ko, W. I.
2014-01-01
The degree of fuel burnup is an important technical parameter to the nuclear fuel cycle, being sensitive and progressive to reduce the total volume of process flow materials and eventually cut the nuclear fuel cycle costs. This paper performed the sensitivity analysis of the total nuclear fuel cycle costs to changes in the technical parameter by varying the degree of burnups in each of the three nuclear fuel cycles using an equilibrium model. Important as burnup does, burnup effect was used among the cost drivers of fuel cycle, as the technical parameter. The fuel cycle options analyzed in this paper are three different fuel cycle options as follows: PWR-Once Through Cycle(PWR-OT), PWR-MOX Recycle, Pyro-SFR Recycle. These fuel cycles are most likely to be adopted in the foreseeable future. As a result of the sensitivity analysis on burnup effect of each three different nuclear fuel cycle costs, PWR-MOX turned out to be the most influenced by burnup changes. Next to PWR-MOX cycle, in the order of Pyro-SFR and PWR-OT cycle turned out to be influenced by the degree of burnup. In conclusion, the degree of burnup in the three nuclear fuel cycles can act as the controlling driver of nuclear fuel cycle costs due to a reduction in the volume of spent fuel leading better availability and capacity factors. However, the equilibrium model used in this paper has a limit that time-dependent material flow and cost calculation is impossible. Hence, comparative analysis of the results calculated by dynamic model hereafter and the calculation results using an equilibrium model should be proceed. Moving forward to the foreseeable future with increasing burnups, further studies regarding alternative material of high corrosion resistance fuel cladding for the overall
Improving the Amazonian Hydrologic Cycle in a Coupled Land-Atmosphere, Single Column Model
Harper, A. B.; Denning, S.; Baker, I.; Prihodko, L.; Branson, M.
2006-12-01
We have coupled a land-surface model, the Simple Biosphere Model (SiB3), to a single column of the Colorado State University General Circulation Model (CSU-GCM) in the Amazon River Basin. This is a preliminary step in the broader goal of improved simulation of Basin-wide hydrology. A previous version of the coupled model (SiB2) showed drought and catastrophic dieback of the Amazon rain forest. SiB3 includes updated soil hydrology and root physiology. Our test area for the coupled single column model is near Santarem, Brazil, where measurements from the km 83 flux tower in the Tapajos National Forest can be used to evaluate model output. The model was run for 2001 using NCEP2 Reanalysis as driver data. Preliminary results show that the updated biosphere model coupled to the GCM produces improved simulations of the seasonal cycle of surface water balance and precipitation. Comparisons of the diurnal and seasonal cycles of surface fluxes are also being made.
A universal order parameter for synchrony in networks of limit cycle oscillators
Schröder, Malte; Timme, Marc; Witthaut, Dirk
2017-07-01
We analyze the properties of order parameters measuring synchronization and phase locking in complex oscillator networks. First, we review network order parameters previously introduced and reveal several shortcomings: none of the introduced order parameters capture all transitions from incoherence over phase locking to full synchrony for arbitrary, finite networks. We then introduce an alternative, universal order parameter that accurately tracks the degree of partial phase locking and synchronization, adapting the traditional definition to account for the network topology and its influence on the phase coherence of the oscillators. We rigorously prove that this order parameter is strictly monotonously increasing with the coupling strength in the phase locked state, directly reflecting the dynamic stability of the network. Furthermore, it indicates the onset of full phase locking by a diverging slope at the critical coupling strength. The order parameter may find applications across systems where different types of synchrony are possible, including biological networks and power grids.
Methodologies for evaluating the proliferation resistance of nuclear fuel cycles
International Nuclear Information System (INIS)
Shiotani, Hiroki; Hori, Kei-ichiro; Takeda, Hiroshi
2001-01-01
The Japan Nuclear Cycle Development Institute (JNC) believes that the development of future nuclear fuel cycle technology should be conducted with careful consideration given to non-proliferation. JNC is studying methodologies for evaluating proliferation resistance of nuclear fuel cycle technologies. However, it is difficult to establish the methodology for evaluating proliferation resistance since the results greatly depend on the assumption for the evaluation and the surrounding conditions. This study grouped factors of proliferation resistance into categories through reviewing past studies and studied the relationships between the factors. Then, this study tried to find vulnerable nuclear material (plutonium) in some FBR fuel cycles from the proliferation perspective, and calculated the time it takes to convert the materials from various nuclear fuel cycles into pure plutonium metal under some assumptions. The result showed that it would take a long time to convert the nuclear materials from the FBR fuel cycles without plutonium separation. While it is a preliminary attempt to evaluate a technical factor of proliferation resistance as the basis of the institutional proliferation resistance, the JNC hopes that it will contribute to future discussions in this area. (author)
Public health risks associated with the CANDU nuclear fuel cycle
International Nuclear Information System (INIS)
Paskievici, W.; Zikovsky, L.
1983-06-01
This report analyzes in a preliminary way the risks to the public posed by the CANDU nuclear fuel cycle. Part 1 considers radiological risks, while part 2 (published as INFO-0141-2) evaluates non-radiological risks. The report concludes that, for radiological risks, maximum individual risks to members of the public are less than 10 -5 per year for postulated accidents, are less than 1 percent of regulatory limits for normal operation and that collective doses are small, less than 3 person-sieverts. It is also concluded that radiological risks are much smaller than the non-radiological risks posed by activities of the nuclear fuel cycle
Regional fuel cycle centres for South and South-East Asia
International Nuclear Information System (INIS)
Ali, M.I.
1977-01-01
A brief preliminary analysis of the economic feasibility of regional fuel cycle centres in South and South-East Asia is presented. The indicative break-even costs and break-even plant sizes for the various fuel cycle services are estimated and the timing for their establishment on the basis of IAEA and ESCAP nuclear power projections in the region are shown. The paper discusses the need for achieving regional self-sufficiency for nuclear fuel services and suggests that a detailed study should be undertaken by the IAEA in close co-operation with the countries of the region to find out their requirements for nuclear fuel services. (author)
Parameter optimization for surface flux transport models
Whitbread, T.; Yeates, A. R.; Muñoz-Jaramillo, A.; Petrie, G. J. D.
2017-11-01
Accurate prediction of solar activity calls for precise calibration of solar cycle models. Consequently we aim to find optimal parameters for models which describe the physical processes on the solar surface, which in turn act as proxies for what occurs in the interior and provide source terms for coronal models. We use a genetic algorithm to optimize surface flux transport models using National Solar Observatory (NSO) magnetogram data for Solar Cycle 23. This is applied to both a 1D model that inserts new magnetic flux in the form of idealized bipolar magnetic regions, and also to a 2D model that assimilates specific shapes of real active regions. The genetic algorithm searches for parameter sets (meridional flow speed and profile, supergranular diffusivity, initial magnetic field, and radial decay time) that produce the best fit between observed and simulated butterfly diagrams, weighted by a latitude-dependent error structure which reflects uncertainty in observations. Due to the easily adaptable nature of the 2D model, the optimization process is repeated for Cycles 21, 22, and 24 in order to analyse cycle-to-cycle variation of the optimal solution. We find that the ranges and optimal solutions for the various regimes are in reasonable agreement with results from the literature, both theoretical and observational. The optimal meridional flow profiles for each regime are almost entirely within observational bounds determined by magnetic feature tracking, with the 2D model being able to accommodate the mean observed profile more successfully. Differences between models appear to be important in deciding values for the diffusive and decay terms. In like fashion, differences in the behaviours of different solar cycles lead to contrasts in parameters defining the meridional flow and initial field strength.
Fuel Cycle of VVER-1000: technical and economic aspects
International Nuclear Information System (INIS)
Kosourov, E.; Pavlov, V.; Pavlovichev, A.
2009-01-01
The paper contains estimations of dependences of technical and economic characteristics of VVER-1000 fuel cycle on number of charged FAs and their enrichment. In the study following restrictions were used: minimum quantity of loaded fresh FAs is equal 36 FAs, a maximum one - 78 (79) FAs and fuel enrichment is limited by value 4,95 %. The following technical and economic characteristics are discussed: cycle length, average burnup of spent fuel, specific consumption of natural uranium, specific quantity of separative work, annual production of thermal energy, fuel component of electrical energy cost, electricity generation cost. Results of estimations are presented as dependences of researched characteristics on cycle length, quantity of loaded FAs and their enrichments. The presented information allows to show tendencies and ranges of technical and economic characteristics at change of fuel cycle parameters. This information can be useful for definition of the fuel cycle parameters which satisfy the requirements of power system and exploiting organizations. (authors)
Large-scale fuel cycle centres
International Nuclear Information System (INIS)
Smiley, S.H.; Black, K.M.
1977-01-01
material controls on an international scale, and the lack of a technological requirement for co-location (on a national basis) of fuel cycle facilities, has led to the concept of the multinational fuel cycle facility. However, the establishment of such a facility requires resolution of a number of unusual factors, broadly characterized as: (1) Administrative and organizational; (2) Economic and financial; (3) Technical; and (4) Operational. Each of these broad areas has been examined on a preliminary basis for a particular geographic region on behalf of a multinational group of organizations to determine the feasibility of the concept and to identify the problems that need to be overcome to ensure its ultimate success. (author)
A study on different thermodynamic cycle schemes coupled with a high temperature gas-cooled reactor
International Nuclear Information System (INIS)
Qu, Xinhe; Yang, Xiaoyong; Wang, Jie
2017-01-01
Highlights: • The features of three different power generation schemes, including closed Brayton cycle, non-reheating combined cycle and reheating combined cycle, coupled with high temperature gas-cooled reactor (HTGR) were investigated and compared. • The effects and mechanism of reactor core outlet temperature, compression ratio and other key parameters over cycle characteristics were analyzed by the thermodynamic models.. • It is found that reheated combined cycle has the highest efficiency. Reactor outlet temperature and main steam parameters are key factors to improve the cycle’s performance. - Abstract: With gradual increase in reactor outlet temperature, the efficient power conversion technology has become one of developing trends of (very) high temperature gas-cooled reactors (HTGRs). In this paper, different cycle power generation schemes for HTGRs were systematically studied. Physical and mathematical models were established for these three cycle schemes: closed Brayton cycle, simple combined cycle, and reheated combined cycle. The effects and mechanism of key parameters such as reactor core outlet temperature, reactor core inlet temperature and compression ratio on the features of these cycles were analyzed. Then, optimization results were given with engineering restrictive conditions, including pinch point temperature differences. Results revealed that within the temperature range of HTGRs (700–900 °C), the reheated combined cycle had the highest efficiency, while the simple combined cycle had the lowest efficiency (900 °C). The efficiencies of the closed Brayton cycle, simple combined cycle and reheated combined cycle are 49.5%, 46.6% and 50.1%, respectively. These results provide insights on the different schemes of these cycles, and reveal the effects of key parameters on performance of these cycles. It could be helpful to understand and develop a combined cycle coupled with a high temperature reactor in the future.
Understanding Solar Cycle Variability
Energy Technology Data Exchange (ETDEWEB)
Cameron, R. H.; Schüssler, M., E-mail: cameron@mps.mpg.de [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)
2017-07-10
The level of solar magnetic activity, as exemplified by the number of sunspots and by energetic events in the corona, varies on a wide range of timescales. Most prominent is the 11-year solar cycle, which is significantly modulated on longer timescales. Drawing from dynamo theory, together with the empirical results of past solar activity and similar phenomena for solar-like stars, we show that the variability of the solar cycle can be essentially understood in terms of a weakly nonlinear limit cycle affected by random noise. In contrast to ad hoc “toy models” for the solar cycle, this leads to a generic normal-form model, whose parameters are all constrained by observations. The model reproduces the characteristics of the variable solar activity on timescales between decades and millennia, including the occurrence and statistics of extended periods of very low activity (grand minima). Comparison with results obtained with a Babcock–Leighton-type dynamo model confirm the validity of the normal-mode approach.
Cappelle, Tessa; Fink, Bernhard
2013-10-10
Women's preferences for putative cues of genetic quality in men's voices, faces, bodies, and behavioral displays are stronger during the fertile phase of the ovulatory cycle. Here we show that ovulatory cycle-related changes in women's attractiveness perceptions of male features are also found with dance movements, especially those perceived as highly masculine. Dance movements of 79 British men were recorded with an optical motion-capture system whilst dancing to a basic rhythm. Virtual humanoid characters (avatars) were created and converted into 15-second video clips and rated by 37 women on masculinity. Another 23 women judged the attractiveness of the 10 dancers who scored highest and those 10 who scored lowest on masculinity once in days of high fertility and once in days of low fertility of their ovulatory cycle. High-masculine dancers were judged higher on attractiveness around ovulation than on other cycle days, whilst no such perceptual difference was found for low-masculine dancers. We suggest that women may gain fitness benefits from evolved preferences for masculinity cues they obtain from male dance movements.
Directory of Open Access Journals (Sweden)
Tessa Cappelle
2013-07-01
Full Text Available Women's preferences for putative cues of genetic quality in men's voices, faces, bodies, and behavioral displays are stronger during the fertile phase of the ovulatory cycle. Here we show that ovulatory cycle-related changes in women's attractiveness perceptions of male features are also found with dance movements, especially those perceived as highly masculine. Dance movements of 79 British men were recorded with an optical motion-capture system whilst dancing to a basic rhythm. Virtual humanoid characters (avatars were created and converted into 15-second video clips and rated by 37 women on masculinity. Another 23 women judged the attractiveness of the 10 dancers who scored highest and those 10 who scored lowest on masculinity once in days of high fertility and once in days of low fertility of their ovulatory cycle. High-masculine dancers were judged higher on attractiveness around ovulation than on other cycle days, whilst no such perceptual difference was found for low-masculine dancers. We suggest that women may gain fitness benefits from evolved preferences for masculinity cues they obtain from male dance movements.
Study on the supercritical CO2 power cycles for landfill gas firing gas turbine bottoming cycle
International Nuclear Information System (INIS)
Kim, Min Seok; Ahn, Yoonhan; Kim, Beomjoo; Lee, Jeong Ik
2016-01-01
In this paper, a comparison of nine supercritical carbon dioxide (S-CO 2 ) bottoming power cycles in conjunction with a topping cycle of landfill gas (LFG) fired 5MWe gas turbine is presented. For the comparison purpose, a sensitivity study of the cycle design parameters for nine different cycles was conducted and each cycle thermodynamic performance is evaluated. In addition, the cycle performance evaluation dependency on the compressor inlet temperature variation is performed to investigate how S-CO 2 cycles sensitive to the heat sink temperature variation. Furthermore, the development of new S-CO 2 cycle layouts is reported and the suggested cycles' performances are compared to the existing cycle layouts. It was found that a recompression cycle is not suitable for the bottoming cycle application, but a partial heating cycle has relatively higher net produced work with a simple layout and small number of components. Although a dual heated and flow split cycle has the highest net produced work, it has disadvantages of having numerous components and complex process which requires more sophisticated operational strategies. This study identified that the recuperation process is much more important than the intercooling process to the S-CO 2 cycle design for increasing the thermal efficiency and the net produced work point of view. - Highlights: • Study of nine S-CO 2 power cycle layouts for a small scale landfill gas power generation application. • Development of new S-CO 2 cycle layouts. • Sensitivity analysis of S-CO 2 cycles to evaluate and compare nine cycles' performances.
Economic comparison of fusion fuel cycles
International Nuclear Information System (INIS)
Brereton, S.J.; Kazimi, M.S.
1987-01-01
The economics of the DT, DD, and DHe fusion fuel cycles are evaluated by comparison on a consistent basis. The designs for the comparison employ HT-9 structure and helium coolant; liquid lithium is used as the tritium breeding material for the DT fuel cycle. The reactors are pulsed, superconducting tokamaks, producing 1200 MW of electric power. The DT and DD designs scan a range of values of plasma beta, assuming first stability scaling laws. The results indicate that on a purely economic basis, the DT fuel cycle is superior to both of the advanced fuel cycles. Geometric factors, materials limitations, and plasma beta were seen to have an impact on the Cost of Electricity (COE). The economics for the DD fuel cycle are more strongly affected by these parameters than is the DT fuel cycle. Fuel costs are a major factor in determining the COE for the DHe fuel cycle. Based on costs directly attributable to the fuel cycle, the DT fuel cycle appears most attractive. Technological advances, improved understanding of physics, or strides in advanced energy conversion schemes may result in altering the economic ranking of the fuel cycles indicated here. 7 refs., 6 figs., 2 tabs
Kinetic parameters of nitridation of molybdenum and niobium alloys with various structure states
International Nuclear Information System (INIS)
Solodkin, G.A.; Bulgach, A.A.; Likhacheva, T.E.
1985-01-01
Effect of preliminary plastic strain under rolling on kinetic parameters of nitridation of VN-2AEh, VN-3 niobium alloys and molybdenum alloy with hafnium is investigated. Extreme character of dependence of kinetic parameters of nitridation on the degree of reduction under rolling is determined. Preliminary plastic strain at negligible reduction is shown to accelerate growth of the zone of internal nitridation and decelerates growth of the nitride zone. Nitrogen atom removal from the surface to the centre is retarded at the increase of the degree of reduction up to 50% and higher. The degree of deformations is the higher the lower nitridation temperature is
Control system options and strategies for supercritical CO2 cycles.
Energy Technology Data Exchange (ETDEWEB)
Moisseytsev, A.; Kulesza, K. P.; Sienicki, J. J.; Nuclear Engineering Division; Oregon State Univ.
2009-06-18
well as the benefits in expanding the range over which individual control mechanisms are effective for cycle control. However, a combination of mechanisms is still required for control of the S-CO{sub 2} Brayton Cycle between 0 and 100 % load. An effort is underway to partially validate the Argonne models and codes by means of comparison with data from tests carried out using the small-scale Sandia Brayton Loop (SBL) recuperated gas closed Brayton cycle facility. The centrifugal compressor model has been compared with data from the SBL operating with nitrogen gas and good agreement is obtained between calculations and the measured data for the compressor outlet pressure versus flow rate, although it is necessary to assume values for certain model parameters which require information about the configuration or dimensions of the compressor components that is unavailable. Unfortunately, the compressor efficiency cannot be compared with experiment data due to the lack of outlet temperature data. A radial inflow turbine model has been developed to enable further comparison of calculations with data from the SBL which incorporates both a radial inflow turbine as well as a radial compressor. Preliminary calculations of pressure ratio and efficiency versus flow rate have been carried out using the radial inflow turbine model.
Control system options and strategies for supercritical CO2 cycles
International Nuclear Information System (INIS)
Moisseytsev, A.; Kulesza, K.P.; Sienicki, J.J.
2009-01-01
over which individual control mechanisms are effective for cycle control. However, a combination of mechanisms is still required for control of the S-CO 2 Brayton Cycle between 0 and 100 % load. An effort is underway to partially validate the Argonne models and codes by means of comparison with data from tests carried out using the small-scale Sandia Brayton Loop (SBL) recuperated gas closed Brayton cycle facility. The centrifugal compressor model has been compared with data from the SBL operating with nitrogen gas and good agreement is obtained between calculations and the measured data for the compressor outlet pressure versus flow rate, although it is necessary to assume values for certain model parameters which require information about the configuration or dimensions of the compressor components that is unavailable. Unfortunately, the compressor efficiency cannot be compared with experiment data due to the lack of outlet temperature data. A radial inflow turbine model has been developed to enable further comparison of calculations with data from the SBL which incorporates both a radial inflow turbine as well as a radial compressor. Preliminary calculations of pressure ratio and efficiency versus flow rate have been carried out using the radial inflow turbine model.
Dynamical analysis of a cubic Liénard system with global parameters
Chen, Hebai; Chen, Xingwu
2015-10-01
In this paper we investigate the dynamical behaviour of a cubic Liénard system with global parameters. After analysing the qualitative properties of all the equilibria and judging the existences of limit cycles and homoclinic loops for the whole parameter plane, we give the bifurcation diagram and phase portraits. Phase portraits are global if there exist limit cycles and local otherwise. We prove that parameters lie in a connected region, not just on a curve, usually in the parameter plane when the system has one homoclinic loop. Moreover, for global parameters we give a positive answer to conjecture 3.2 of (1998 Nonlinearity 11 1505-19) in the case of exactly two equilibria about the existence of some function whose graph is exactly the surface of double limit cycles. Supported by NSFC 11471228, 11172246 and the Fundamental Research Funds for the Central Universities.
Economic analysis of extended cycles in the Laguna Verde nuclear power plant
International Nuclear Information System (INIS)
Hernandez N, H.; Hernandez M, J.L.; Francois L, J.L.
2004-01-01
The present work presents a preliminary analysis of economic type of extended cycles of operation of the Unit One in the Laguna Verde nuclear power plant. It is analysed an equilibrium cycle of 18 months firstly, with base to the Plan of Use of Energy of the Federal Commission of Electricity, being evaluated the cost of the energy until the end of the useful life of the plant. Later on an alternative recharge scenario is presented with base to an equilibrium cycle of 24 months, implemented to the beginning of the cycle 11, without considering transition cycles. It is added in both cycles the cost of the substitution energy, considering the unitary cost of the fuel of a dual thermoelectric power station of 350 M We and evaluating in each operation cycle, in both scenarios, the value of the substitution energy. The results show that a reduction of the days of recharge in the cycle of 24 months could make this option but favorable economically. The duration of the period of recharge rebounds in considerable grade in the cost of energy generation for concept of fuel. (Author)
General Concerns Life-Cycle Design of Economical Ice-Resistant Structures in the Bohai Sea
Directory of Open Access Journals (Sweden)
Zhang Da-yong
2017-08-01
Full Text Available In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both iceresistant and economical offshore platforms. However, there are many risks during the life cycle of offshore platforms due to the imperfect preliminary design for the Bohai Sea economical ice-resistant structures. As a result, the whole life-cycle design should be considered, including plan, design, construction, management and maintenance design. Based on the demand of existing codes and research of the basic design, structural ice-resistant performance and the reasonable management and maintenance, the life-cycle design theory is discussed. It was concluded that the life-cycle cost-effective optimum design proposed will lead to a minimum risk.
Optimization of the triple-pressure combined cycle power plant
Directory of Open Access Journals (Sweden)
Alus Muammer
2012-01-01
Full Text Available The aim of this work was to develop a new system for optimization of parameters for combined cycle power plants (CCGTs with triple-pressure heat recovery steam generator (HRSG. Thermodynamic and thermoeconomic optimizations were carried out. The objective of the thermodynamic optimization is to enhance the efficiency of the CCGTs and to maximize the power production in the steam cycle (steam turbine gross power. Improvement of the efficiency of the CCGT plants is achieved through optimization of the operating parameters: temperature difference between the gas and steam (pinch point P.P. and the steam pressure in the HRSG. The objective of the thermoeconomic optimization is to minimize the production costs per unit of the generated electricity. Defining the optimal P.P. was the first step in the optimization procedure. Then, through the developed optimization process, other optimal operating parameters (steam pressure and condenser pressure were identified. The developed system was demonstrated for the case of a 282 MW CCGT power plant with a typical design for commercial combined cycle power plants. The optimized combined cycle was compared with the regular CCGT plant.
Ultrasonic preliminary measurements of oenological malolactic fermentation parameters in red wine
Novoa-Díaz, D. F.; Puig-Pujol, A.; García-Álvarez, J.; Chávez, J. A.; Turó, A.; Mínguez, S.; García-Hernández, M. J.; Bertran, E.; Salazar, J.
2012-12-01
In the winemaking process, the malolactic fermentation is an essential process in the production of high quality red wines which concerns the conversion of malate into lactate. In this work, the ultrasonic velocity through wine samples with different concentrations of malate and lactate was measured using the pulse echo technique with 1 MHz tone burst signals. The evolution of these concentrations during malolactic fermentation was taken into account in order to determine the ratio between concentrations of malate and lactate of the different samples. These preliminary results have revealed that the ultrasonic velocity increases during the conversion of malate to lactate. In addition, measurements have been conducted to quantify the influence of variations in turbidity and temperature on test samples. Therefore, these results show the possibility of using ultrasonic velocity measurements for on-line monitoring the malolactic fermentation of red wine and may help to improve and contribute to the development of the winemaking process.
Ultrasonic preliminary measurements of oenological malolactic fermentation parameters in red wine
International Nuclear Information System (INIS)
Novoa-Díaz, D F; García-Álvarez, J; Chávez, J A; Turó, A; García-Hernández, M J; Salazar, J; Puig-Pujol, A; Mínguez, S; Bertran, E
2012-01-01
In the winemaking process, the malolactic fermentation is an essential process in the production of high quality red wines which concerns the conversion of malate into lactate. In this work, the ultrasonic velocity through wine samples with different concentrations of malate and lactate was measured using the pulse echo technique with 1 MHz tone burst signals. The evolution of these concentrations during malolactic fermentation was taken into account in order to determine the ratio between concentrations of malate and lactate of the different samples. These preliminary results have revealed that the ultrasonic velocity increases during the conversion of malate to lactate. In addition, measurements have been conducted to quantify the influence of variations in turbidity and temperature on test samples. Therefore, these results show the possibility of using ultrasonic velocity measurements for on-line monitoring the malolactic fermentation of red wine and may help to improve and contribute to the development of the winemaking process.
Spectral shift controlled reactor, UO2 once-through cycle optimized
International Nuclear Information System (INIS)
1978-05-01
This paper presents technical and economic data on the SSCR which may be of use in the International Fuel Cycle Evaluation Program to intercompare alternative nuclear systems. Included in this data is information on the optimized UO 2 once-through fuel cycle. The ''optimized'' cycle refers to a UO 2 once-through cycle which has better fuel resource utilization than the conventional UO 2 cycle employed in current design PWRs. This fuel cycle uses more in-core batches and a higher discharge exposure than current PWR fuel management schemes. The proposed cycle is not optimal in a mathematical sense, however, since additional resource savings can be obtained if the discharge exposure is extended to even higher values and the number of in-core fuel batches is increased further. The present cycle was selected as ''optimal'' based on the assumption that it can be achieved with only an extension of fuel design technology and can therefore be deployed in a relatively short time frame. In the longer term, modification to reactor geometry as well as further extensions of discharge burnup might be considered to realize additional reduction in uranium resource requirements. The data contained in this paper has been developed by an ongoing program which at the present time is only 50% complete. The data presented here should therefore be considered preliminary and will be updated in the future as required
Sullivan, T. J.; Parker, D. E.
1979-01-01
A design technology study was performed to identify a high speed, multistage, variable geometry fan configuration capable of achieving wide flow modulation with near optimum efficiency at the important operating condition. A parametric screening study of the front and rear block fans was conducted in which the influence of major fan design features on weight and efficiency was determined. Key design parameters were varied systematically to determine the fan configuration most suited for a double bypass, variable cycle engine. Two and three stage fans were considered for the front block. A single stage, core driven fan was studied for the rear block. Variable geometry concepts were evaluated to provide near optimum off design performance. A detailed aerodynamic design and a preliminary mechanical design were carried out for the selected fan configuration. Performance predictions were made for the front and rear block fans.
Trubienko, Olga; Fleitout, Luce; Garaud, Jean-Didier; Vigny, Christophe
2013-03-01
The deformations of the overriding and subducting plates during the seismic cycle associated with large subduction earthquakes are modelled using 2D and 3D finite element techniques. A particular emphasis is put on the interseismic velocities and on the impact of the rheology of the asthenosphere. The distance over which the seismic cycle perturbs significantly the velocities depends upon the ratio of the viscosity in the asthenosphere to the period of the seismic cycle and can reach several thousand km for rheological parameters deduced from the first years of deformation after the Aceh earthquake. For a same early postseismic velocity, a Burger rheology of the asthenosphere implies a smaller duration of the postseismic phase and thus smaller interseismic velocities than a Maxwell rheology. A low viscosity wedge (LVW) modifies very significantly the predicted horizontal and vertical motions in the near and middle fields. In particular, with a LVW, the peak in vertical velocity at the end of the cycle is predicted to be no longer above the deep end of the locked section of the fault but further away, above the continentward limit of the LVW. The lateral viscosity variations linked to the presence at depth of the subducting slab affect substantially the results. The north-south interseismic compression predicted by this preliminary 2D model over more than 1500 km within the Sunda block is in good agreement with the pre-2004 velocities with respect to South-China inferred from GPS observations in Thailand, Malaysia and Indonesia. In Japan, before the Tohoku earthquake, the eastern part of northern Honshu was subsiding while the western part was uplifting. This transition from subsidence to uplift so far away from the trench is well fitted by the predictions from our models involving a LVW. Most of the results obtained here in a 2D geometry are shown to provide a good estimate of the displacements for fault segments of finite lateral extent, with a 3D spherical
Preliminary study of soil permeability properties using principal component analysis
Yulianti, M.; Sudriani, Y.; Rustini, H. A.
2018-02-01
Soil permeability measurement is undoubtedly important in carrying out soil-water research such as rainfall-runoff modelling, irrigation water distribution systems, etc. It is also known that acquiring reliable soil permeability data is rather laborious, time-consuming, and costly. Therefore, it is desirable to develop the prediction model. Several studies of empirical equations for predicting permeability have been undertaken by many researchers. These studies derived the models from areas which soil characteristics are different from Indonesian soil, which suggest a possibility that these permeability models are site-specific. The purpose of this study is to identify which soil parameters correspond strongly to soil permeability and propose a preliminary model for permeability prediction. Principal component analysis (PCA) was applied to 16 parameters analysed from 37 sites consist of 91 samples obtained from Batanghari Watershed. Findings indicated five variables that have strong correlation with soil permeability, and we recommend a preliminary permeability model, which is potential for further development.
Haass-Koffler, Carolina L; Goodyear, Kimberly; Long, Victoria M; Tran, Harrison H; Loche, Antonella; Cacciaglia, Roberto; Swift, Robert M; Leggio, Lorenzo
2017-12-01
The data in this article outline the methods used for the administration of GET 73 in the first time-in-human manuscript entitled "Phase I randomized clinical trial for the safety, tolerability and preliminary pharmacokinetics of the mGluR5 negative allosteric modulator GET 73 following single and repeated doses in healthy male volunteers" (Haass-Koffler et al., 2017) [1]. Data sets are provided in two different manners. The first series of tables provided includes procedural information about the experiments conducted. The next series of tables provided includes Pharmacokinetic (PK) parameters for GET 73 and its main metabolite MET 2. This set of data is comprised by two experiments: Experiment 1 references a single ascending dose administration of GET 73 and Experiment 2 references a repeated ascending dose administration of GET 73.
Preliminary power train design for a state-of-the-art electric vehicle
Ross, J. A.; Wooldridge, G. A.
1978-01-01
The state-of-the-art (SOTA) of electric vehicles built since 1965 was reviewed to establish a base for the preliminary design of a power train for a SOTA electric vehicle. The performance of existing electric vehicles were evaluated to establish preliminary specifications for a power train design using state-of-the-art technology and commercially available components. Power train components were evaluated and selected using a computer simulation of the SAE J227a Schedule D driving cycle. Predicted range was determined for a number of motor and controller combinations in conjunction with the mechanical elements of power trains and a battery pack of sixteen lead-acid batteries - 471.7 kg at 0.093 MJ/Kg (1040 lbs. at 11.7 Whr/lb). On the basis of maximum range and overall system efficiency using the Schedule D cycle, an induction motor and 3 phase inverter/controller was selected as the optimum combination when used with a two-speed transaxle and steel belted radial tires. The predicted Schedule D range is 90.4 km (56.2 mi). Four near term improvements to the SOTA were identified, evaluated, and predicted to increase range approximately 7%.
Selected aspects of operation of supercritical (transcritical organic Rankine cycle
Directory of Open Access Journals (Sweden)
Mocarsk Szymon
2015-06-01
Full Text Available The paper presents a literature review on the topic of vapour power plants working according to the two-phase thermodynamic cycle with supercritical parameters. The main attention was focused on a review of articles and papers on the vapour power plants working using organic circulation fluids powered with low- and medium-temperature heat sources. Power plants with water-steam cycle supplied with a high-temperature sources have also been shown, however, it has been done mainly to show fundamental differences in the efficiency of the power plant and applications of organic and water-steam cycles. Based on a review of available literature references a comparative analysis of the parameters generated by power plants was conducted, depending on the working fluid used, the type and parameters of the heat source, with particular attention to the needs of power plant internal load.
Automated extraction and validation of children's gait parameters with the Kinect.
Motiian, Saeid; Pergami, Paola; Guffey, Keegan; Mancinelli, Corrie A; Doretto, Gianfranco
2015-12-02
Gait analysis for therapy regimen prescription and monitoring requires patients to physically access clinics with specialized equipment. The timely availability of such infrastructure at the right frequency is especially important for small children. Besides being very costly, this is a challenge for many children living in rural areas. This is why this work develops a low-cost, portable, and automated approach for in-home gait analysis, based on the Microsoft Kinect. A robust and efficient method for extracting gait parameters is introduced, which copes with the high variability of noisy Kinect skeleton tracking data experienced across the population of young children. This is achieved by temporally segmenting the data with an approach based on coupling a probabilistic matching of stride template models, learned offline, with the estimation of their global and local temporal scaling. A preliminary study conducted on healthy children between 2 and 4 years of age is performed to analyze the accuracy, precision, repeatability, and concurrent validity of the proposed method against the GAITRite when measuring several spatial and temporal children's gait parameters. The method has excellent accuracy and good precision, with segmenting temporal sequences of body joint locations into stride and step cycles. Also, the spatial and temporal gait parameters, estimated automatically, exhibit good concurrent validity with those provided by the GAITRite, as well as very good repeatability. In particular, on a range of nine gait parameters, the relative and absolute agreements were found to be good and excellent, and the overall agreements were found to be good and moderate. This work enables and validates the automated use of the Kinect for children's gait analysis in healthy subjects. In particular, the approach makes a step forward towards developing a low-cost, portable, parent-operated in-home tool for clinicians assisting young children.
Once-through thorium cycles in Candu reactors
International Nuclear Information System (INIS)
Milgram, M.S.
1982-01-01
In once-through thorium cycles pure thorium fuel bundles can be irradiated conjointly with uranium fuel bundles in a CANDU reactor with parameters judiciously chosen such that the overall fuel cycle cost is competitive with other possibilities - notably low-enriched uranium. Uranium 233 can be created and stockpiled for possible future use with no imperative that it be used unless future conditions warrant, and a stockpile can be begun independently of the state of reprocessing technology. The existence and general properties of these cycles are discussed
A preliminary investigation of the design parameters of an air induction nozzle
Energy Technology Data Exchange (ETDEWEB)
Vashahi, Foad; Ra, Sothea; Lee, Jeekeun [Chonbuk National University, Jeonju (Korea, Republic of); Choi, Yong [National Academy of Agricultural Science, Wanju (Korea, Republic of)
2017-07-15
In the present study, an experimental study on design parameters of an air induction nozzle was performed. These nozzles are capable of producing large size droplets, including microbubbles, which in turn results in high drift reduction. A magnified 2D version of an air induction nozzle was designed and manufactured. The manufactured geometries have the ability to be disassembled easily, thus several geometrical parameters are replaced sequentially. The effects of a venturi throat, air orifices and discharge orifice diameters along with the length of the mixing chamber are analyzed. Analysis of the parameters revealed their strength of prediction on the air liquid ratio and the nozzle performance.
International Nuclear Information System (INIS)
Persiani, P.J.
1995-01-01
The purpose of this preliminary investigation is to explore alternatives and strategies aimed at the gradual reduction of the excess inventories of separated plutonium and high-enriched uranium (HEU) in the civilian nuclear power industry. The study attempts to establish a technical and economic basis to assist in the formation of alternative approaches consistent with nonproliferation and safeguards concerns. Reference annual mass flows and inventories for a representative 1,400 Mwe Pressurized Water Reactor (PWR) fuel cycle have been investigated for three cases: the 100 percent uranium oxide UO 2 fuel loading once through cycle, and the 33 percent mixed oxide MOX loading configuration for a first and second plutonium recycle. The analysis addresses fuel cycle developments; plutonium and uranium inventory and flow balances; nuclear fuel processing operations; UO 2 once-through and MOX first and second recycles; and the economic incentives to draw-down the excess separated plutonium stores. The preliminary analysis explores several options in reducing the excess separated plutonium arisings and HEU, and the consequences of the interacting synergistic effects between fuel cycle processes and isotopic signatures of nuclear materials on nonproliferation and safeguards policy assessments
Energy Technology Data Exchange (ETDEWEB)
Graziani, [EURATOM, Ispra (Italy); Trauwaert, [Belgonucleaire (Belgium)
1971-06-16
This note presents some preliminary results of a recent work performed jointly by EURATOM (CCR Ispra) and BELGONUCLEAIRE. The analysis of the results is still in progress and a more comprehensive presentation will be made later. The purpose of the study was the evaluation of the savings in fuel cycle cost which could result from the relaxation of the limits on some fuels parameters - heavy metal loading, burnup and age factor - while keeping unchanged the geometry of the fuel element and that of the reactor. Within the range considered and the economic assumptions used, the most obvious saving which can be obtained from the increase of one of the limits seems that made possible by the increase of heavy metal loading. This saving is 2% in fuel cycle cost without any change in resonance integral and 4.5% with a reduction of 10% in resonance integral. An increase of the admissible burnup is also very rewarding, provided the resonance integral can be increased in order to keep the age factor down to 1.085.
Prospects of the use of nanofluids as working fluids for organic Rankine cycle power systems
DEFF Research Database (Denmark)
Mondejar, Maria E.; Andreasen, Jesper G.; Regidor, Maria
2017-01-01
The search of novel working fluids for organic Rankine cycle power systems is driven by the recent regulations imposing additional phase-out schedules for substances with adverse environmental characteristics. Recently, nanofluids (i.e. colloidal suspensions of nanoparticles in fluids) have been...... suggested as potential working fluids for organic Rankine cycle power systems due to their enhanced thermal properties, potentially giving advantages with respect to the design of the components and the cycle performance. Nevertheless, a number of challenges concerning the use of nanofluids must...... the prospects of using nanofluids as working fluids for organic Rankine cycle power systems. As a preliminary study, nanofluids consisting of a homogenous and stable mixture of different nanoparticles types and a selected organic fluid are simulated on a case study organic Rankine cycle unit for waste heat...
Patterson, Richard L.; Hammoud, Ahmad
2012-01-01
Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These Include radiation, extreme temperatures, thermal cycling, to name a few. Preliminary data obtained on new Gallium Nitride and Silicon Carbide power devices under exposure to radiation followed by long term thermal cycling are presented. This work was done in collaboration with GSFC and JPL in support of the NASA Electronic Parts and Packaging (NEPP) Program
Plausibility of Menstrual Cycle Apps Claiming to Support Conception.
Freis, Alexander; Freundl-Schütt, Tanja; Wallwiener, Lisa-Maria; Baur, Sigfried; Strowitzki, Thomas; Freundl, Günter; Frank-Herrmann, Petra
2018-01-01
The interval of peak fertility during the menstrual cycle is of limited duration, and the day of ovulation varies, even in women with fairly regular cycles. Therefore, menstrual cycle apps identifying the "fertile window" for women trying to conceive must be quite precise. A deviation of a few days may lead the couple to focus on less- or non-fertile days for sexual intercourse and thus may be worse than random intercourse. The aim of the present investigation was to develop a scoring system for rating available apps for determining the fertile window and secondarily pilot test 12 apps currently available in both German and English (consisting of 6 calendar-based apps: Clue Menstruations- und Zykluskalender, Flo Menstruationskalender, Maya-Mein Periodentracker, Menstruationskalender Pro, Period Tracker Deluxe, and WomanLog-Pro-Kalender; 2 calculothermal apps: Ovy and Natural Cycles; and 4 symptothermal apps: myNFP, Lady Cycle, Lily, and OvuView). The calendar-based apps were investigated by entering several series of cycles with varying lengths, whereas the symptom-based apps were examined by entering data of cycles with known temperature rise, cervical mucus pattern, and clinical ovulation. The main criteria for evaluating the cycle apps were as follows: (1) What methods/parameters were used to determine the fertile window? (2) What study results exist concerning that underlying method/parameters? (3) What study results exist concerning the app itself? (4) Was there a qualified counseling service? The calendar-based apps predicted the fertile days based on data of previous cycles. They obtained zero points in our scoring system, as they did not comply with any of the evaluated criteria. Calculothermal apps had similar deficits for predicting the most fertile days and produced suboptimal results (Ovy 3/30 points and Natural Cycles 2/30 points). The symptothermal apps determined the fertile days based on parameters of the current cycle: Lady Cycle scored 20
Three-batch reloading scheme for IRIS reactor extended cycles
International Nuclear Information System (INIS)
Jecmenica, R.; Pevec, D.; Grgic, D.
2004-01-01
To fully exploit the IRIS reactor optimized maintenance, and at the same time improve fuel utilization, a core design enabling a 4-year operating cycle together with a three-batch reloading scheme is desirable. However, this requires not only the increased allowed burnup but also use of fuel with uranium oxide enriched beyond 5%. This paper considers three-batch reloading scheme for a 4-year operating cycle with the assumptions of increased discharge burnup and fuel enrichment beyond 5%. Calculational model of IRIS reactor core has been developed based on FER FA2D code for group constants generation and NRC's PARCS nodal code for global core analysis. Studies have been performed resulting in a preliminary design of a three-batch core configuration for the first cycle. It must be emphasized that this study is outside the current IRIS licensing efforts, which rely on the present fuel technology (enrichment below 5%), but it is of long-term interest for potential future IRIS design upgrades. (author)
Preliminary analysis of 500 MWt MHD power plant with oxygen enrichment
1980-04-01
An MHD Engineering Test Facility design concept is analyzed. A 500 MWt oxygen enriched MHD topping cycle integrated for combined cycle operation with a 400 MWe steam plant is evaluated. The MHD cycle uses Montana Rosebud coal and air enriched to 35 mole percent oxygen preheated to 1100 F. The steam plant is a 2535 psia/1000 F/1000 F reheat recycle that was scaled down from the Gilbert/Commonwealth Reference Fossil Plant design series. Integration is accomplished by blending the steam generated in the MHD heat recovery system with steam generated by the partial firing of the steam plant boiler to provide the total flow requirement of the turbine. The major MHD and steam plant auxiliaries are driven by steam turbines. When the MHD cycle is taken out of service, the steam plant is capable of stand-alone operation at turbine design throttle flow. This operation requires the full firing of the steam plant boiler. A preliminary feasibility assessment is given, and results on the system thermodynamics, construction scheduling, and capital costs are presented.
Changes of the thermodynamic parameters in failure conditions of the micro-CHP cycle
Matysko, Robert; Mikielewicz, Jarosław; Ihnatowicz, Eugeniusz
2014-03-01
The paper presents the calculations for the failure conditions of the ORC (organic Rankine cycle) cycle in the electrical power system. It analyses the possible reasons of breakdown, such as the electrical power loss or the automatic safety valve failure. The micro-CHP (combined heat and power) system should have maintenance-free configuration, which means that the user does not have to be acquainted with all the details of the ORC system operation. However, the system should always be equipped with the safety control systems allowing for the immediate turn off of the ORC cycle in case of any failure. In case of emergency, the control system should take over the safety tasks and protect the micro-CHP system from damaging. Although, the control systems are able to respond quickly to the CHP system equipped with the inertial systems, the negative effects of failure are unavoidable and always remain for some time. Moreover, the paper presents the results of calculations determining the inertia for the micro-CHP system of the circulating ORC pump, heat removal pump (cooling condenser) and the heat supply pump in failure conditions.
Changes of the thermodynamic parameters in failure conditions of the micro-CHP cycle
Directory of Open Access Journals (Sweden)
Matysko Robert
2014-03-01
Full Text Available The paper presents the calculations for the failure conditions of the ORC (organic Rankine cycle cycle in the electrical power system. It analyses the possible reasons of breakdown, such as the electrical power loss or the automatic safety valve failure. The micro-CHP (combined heat and power system should have maintenance-free configuration, which means that the user does not have to be acquainted with all the details of the ORC system operation. However, the system should always be equipped with the safety control systems allowing for the immediate turn off of the ORC cycle in case of any failure. In case of emergency, the control system should take over the safety tasks and protect the micro-CHP system from damaging. Although, the control systems are able to respond quickly to the CHP system equipped with the inertial systems, the negative effects of failure are unavoidable and always remain for some time. Moreover, the paper presents the results of calculations determining the inertia for the micro-CHP system of the circulating ORC pump, heat removal pump (cooling condenser and the heat supply pump in failure conditions.
Fractal Dimension and Maximum Sunspot Number in Solar Cycle
Directory of Open Access Journals (Sweden)
R.-S. Kim
2006-09-01
Full Text Available The fractal dimension is a quantitative parameter describing the characteristics of irregular time series. In this study, we use this parameter to analyze the irregular aspects of solar activity and to predict the maximum sunspot number in the following solar cycle by examining time series of the sunspot number. For this, we considered the daily sunspot number since 1850 from SIDC (Solar Influences Data analysis Center and then estimated cycle variation of the fractal dimension by using Higuchi's method. We examined the relationship between this fractal dimension and the maximum monthly sunspot number in each solar cycle. As a result, we found that there is a strong inverse relationship between the fractal dimension and the maximum monthly sunspot number. By using this relation we predicted the maximum sunspot number in the solar cycle from the fractal dimension of the sunspot numbers during the solar activity increasing phase. The successful prediction is proven by a good correlation (r=0.89 between the observed and predicted maximum sunspot numbers in the solar cycles.
Numerical and Engine Cycle Analyses of a Pulse Laser Ramjet Vehicle
Katsurayama, Hiroshi; Komurasaki, Kimiya; Momozawa, Ai; Arakawa, Yoshihiro
A preliminary feasibility study of a laser ramjet SSTO has been conducted using engine cycle analysis. Although a large amount of laser energy is lost due to chemically frozen flow at high altitudes, the laser ramjet SSTO was found to be feasible with 100 MW laser power for 100 kg vehicle mass and 1 m2 vehicle cross-section area. Obtained momentum coupling coefficient, Cm, was validated by means of CFD. As a result, the engine cycle analysis was under-estimating Cm. This would be because of the strong unsteady energy input in the actual heating process and the spatially localized pressure on the afterbody.
Comparison of two methods for calculating the P sorption capacity parameter in soils
Phosphorus (P) cycling in soils is an important process affecting P movement through the landscape. The P cycling routines in many computer models are based on the relationships developed for the EPIC model. An important parameter required for this model is the P sorption capacity parameter (PSP). I...
Preliminary studies on the closed cycle magneto aerodynamic converter
International Nuclear Information System (INIS)
Ricateau, P.
1964-01-01
Besides the open cycle MHD converters which convert the thermal energy contained in combustion gases, a closed cycle converter which can work with any high temperature heat source and specially with nuclear sources is being very carefully studied. Before proceeding to a practical study of the power station as a whole the performances of the converter itself must be fully investigated. These performances are largely a function of the conductivity of the gas, but this conductivity must not be repaid by a temperature technically unacceptable for the heat exchanger. In the conversion fluid an ionizable seeding vapour such as caesium or potassium is mixed with a carrier gas, helium or argon. Purely thermal ionization is only efficient above 2 500 deg. K, whereas the electric field obtained by Induction in the converter can, under given conditions, increase the electron temperature and produce an ionization rate well above the equilibrium value. This allows the gas to be ionized at moderate temperature. Studies are under way in order to clarify the conditions required to produce extra-thermal ionization in seeded rare gases. Measurements have been performed with a 3-phase 500 kVA plasmatron with potassium-seeded argon. The outgoing gas is fed into a channel where the tensor components of conductivity are measured in the presence of a magnetic field. The values found under thermodynamic equilibrium conditions confirm the simple theory. This is not the case when the electrons are heated. Measurements of the same kind have been made by another method in caesium-seeded helium contained in an isothermal vessel at 1 900 deg. K. There also the equilibrium values are in good agreement, but non-equilibrium ionization seems to be lower than expected. The effect of electron heating inside the converter in the case of argon-. potassium mixture has been considered in a theoretical study. It is shown that the electrode set must be carefully subdivided along the channel, and that
Energy Technology Data Exchange (ETDEWEB)
Huang, Bin; Hu, Erjiang; Huang, Zuohua; Zheng, Jianjun; Liu, Bing; Jiang, Deming [State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an Jiaotong University, 710049 Xi' an (China)
2009-10-15
Study of cycle-by-cycle variations in a spark ignition engine fueled with natural gas-hydrogen blends combined with exhaust gas recirculation (EGR) was conducted. The effects of EGR ratio and hydrogen fraction on engine cycle-by-cycle variations are analyzed. The results show that the cylinder peak pressure, the maximum rate of pressure rise and the indicated mean effective pressure decrease and cycle-by-cycle variations increase with the increase of EGR ratio. Interdependency between the above parameters and their corresponding crank angles of cylinder peak pressure is decreased with the increase of EGR ratio. For a given EGR ratio, combustion stability is promoted and cycle-by-cycle variations are decreased with the increase of hydrogen fraction in the fuel blends. Non-linear relationship is presented between the indicated mean effective pressure and EGR ratio. Slight influence of EGR ratio on indicated mean effective pressure is observed at low EGR ratios while large influence of EGR ratio on indicated mean effective pressure is demonstrated at high EGR ratios. The high test engine speed has lower cycle-by-cycle variations due to the enhancement of air flow turbulence and swirls in the cylinder. Increasing hydrogen fraction can maintain low cycle-by-cycle variations at high EGR ratios. (author)
APEX accelerator cycle for transmutation of long-lived fission wastes
International Nuclear Information System (INIS)
Powell, J.; Steinberg, M.; Takahashi, H.; Grand, P.; Botts, T.; Kouts, H.J.C.
1980-01-01
Based on preliminary studies, some conclusions can be drawn concerning the Accelerator Fuel Enricher and Fission Product Exterminator (APEX). APEX-1 and APEX-2 systems can destroy TU's, 137 Cs, and 90 Sr at acceptable cost and efficiency. The principal difference between APEX-1 and APEX-2 is the in-reactor and in-circuit inventory of 137 Cs and 90 Sr. Stable and low hazard wastes can be disposed of by burial. Accelerator breeders can effectively sustain a fission reactor economy indefinitely. Military waste can be blended into commercial fuel cycle for transmutation. Accelerator and target technologies appear practical and could be developed in a few years. More detailed studies are needed to better define the technical and economic features of the LAFER and APEX cycles, so that comparative assessments can be made between these cycles, as well as with other transmutation and waste disposal concepts
Large-scale fuel cycle centers
International Nuclear Information System (INIS)
Smiley, S.H.; Black, K.M.
1977-01-01
economic penalties of combined centers. The need for effective fissile material controls on an international scale, and the lack of a technologic requirement for co-location (on a national basis) of fuel cycle facilities, has led to the concept of the multinational fuel cycle facility. However, the establishment of such a facility requires resolution of a number of factors not ordinarily needing consideration. These factors can be broadly characterized in four categories: (1) Adminstrative and Organizational; (2) Economic and Financial; (3) Technical; and (4) Operational. Each of these broad areas has been examined on a preliminary basis for a particular geographic region on behalf of a multinational grouping of organizations. The purpose of this examination has been to determine the feasibility of such a concept and to identify the problems that need to be overcome to assure its ultimate success
Tritium fuel cycle modeling and tritium breeding analysis for CFETR
Energy Technology Data Exchange (ETDEWEB)
Chen, Hongli; Pan, Lei; Lv, Zhongliang; Li, Wei; Zeng, Qin, E-mail: zengqin@ustc.edu.cn
2016-05-15
Highlights: • A modified tritium fuel cycle model with more detailed subsystems was developed. • The mean residence time method applied to tritium fuel cycle calculation was updated. • Tritium fuel cycle analysis for CFETR was carried out. - Abstract: Attaining tritium self-sufficiency is a critical goal for fusion reactor operated on the D–T fuel cycle. The tritium fuel cycle models were developed to describe the characteristic parameters of the various elements of the tritium cycle as a tool for evaluating the tritium breeding requirements. In this paper, a modified tritium fuel cycle model with more detailed subsystems and an updated mean residence time calculation method was developed based on ITER tritium model. The tritium inventory in fueling system and in plasma, supposed to be important for part of the initial startup tritium inventory, was considered in the updated mean residence time method. Based on the model, the tritium fuel cycle analysis of CFETR (Chinese Fusion Engineering Testing Reactor) was carried out. The most important two parameters, the minimum initial startup tritium inventory (I{sub m}) and the minimum tritium breeding ratio (TBR{sub req}) were calculated. The tritium inventories in steady state and tritium release of subsystems were obtained.
Economic evaluation of multilateral nuclear fuel cycle approach
International Nuclear Information System (INIS)
Takashima, Ryuta; Kuno, Yusuke; Omoto, Akira; Tanaka, Satoru
2011-01-01
Recently previous works have shown that multilateral nuclear fuel cycle approach has benefits not only of non-proliferation but also of cost effectiveness. This is because for most facilities in nuclear fuel cycle, there exist economies of scale, which has a significant impact on the costs of nuclear fuel cycle. Therefore, the evaluation of economic rationality is required as one of the evaluation factors for the multilateral nuclear fuel cycle approach. In this study, we consider some options with respect to multilateral approaches to nuclear fuel cycle in Asian-Pacific region countries that are proposed by the University of Tokyo. In particular, the following factors are embedded into each type: A) no involvement of assurance of services, B) provision of assurance of services including construction of new facility, without transfer of ownership, and C) provision of assurance of service including construction of new joint facilities with ownership transfer of facilities to multilateral nuclear fuel cycle approach. We show the overnight costs taking into account install and operation of nuclear fuel cycle facilities for each option. The economic parameter values such as uranium price, scale factor, and market output expansion influences the total cost for each option. Thus, we show how these parameter values and economic risks affect the total overnight costs for each option. Additionally, the international facilities could increase the risk of transportation for nuclear material compared to national facilities. We discuss the potential effects of this transportation risk on the costs for each option. (author)
Energy Technology Data Exchange (ETDEWEB)
Allais, V
1998-03-01
This thesis was carried out in the framework of fuel cycles studies in partnership with COGEMA; the aim is to determine physics parameters characterising Boiling Reactor Assemblies. Those reactors Firstly distinguish themselves from Pressurised Water Reactor by the boiling of the moderator in the core and secondary by the strong neutronics heterogeneity due to complex design. The diphasic mixture formed is characterised by the void fraction parameter. The loss of information, and neutronic studies characteristics of Boiling Water Reactors led us to make preliminary studies having in view to quantify the void fraction impact on the isotopics evolution. Studies on neutronics influence of assemblies and control rods from the immediate environment allows to define the cluster size to describe. The radial description optimisation with APOLLO-2 is necessary to improve the calculation performance and to reduce the errors coming from the modelization. The following points were studied: pellet radial discretization, clustering of cells characterized by a similar behaviour, options in flux spatial calculation (interface current formalism), self-shielding optimisation (specific to each isotopes). The three dimensional modelization with CRONOS-2 and the simplified accounting of the thermohydraulics / neutronics coupling done by a procedure developed and written during this thesis, allow an evaluation of axial distribution of void fraction, power and burn-up during the irradiation. The comparison with experimental analytic results of complete assembly and pin samples dissolutions allows the qualification of this procedure and confirms the necessity to take into account the void fraction axial variation during the evolution. The application of an automatic coupling with the DARWIN cycle code will allow a precise burnup calculation to be utilized in an industrial procedure. (author)
Optimal cure cycle design of a resin-fiber composite laminate
Hou, Jean W.; Sheen, Jeenson
1987-01-01
A unified computed aided design method was studied for the cure cycle design that incorporates an optimal design technique with the analytical model of a composite cure process. The preliminary results of using this proposed method for optimal cure cycle design are reported and discussed. The cure process of interest is the compression molding of a polyester which is described by a diffusion reaction system. The finite element method is employed to convert the initial boundary value problem into a set of first order differential equations which are solved simultaneously by the DE program. The equations for thermal design sensitivities are derived by using the direct differentiation method and are solved by the DE program. A recursive quadratic programming algorithm with an active set strategy called a linearization method is used to optimally design the cure cycle, subjected to the given design performance requirements. The difficulty of casting the cure cycle design process into a proper mathematical form is recognized. Various optimal design problems are formulated to address theses aspects. The optimal solutions of these formulations are compared and discussed.
Episode cycles with increasing recurrences in first-episode bipolar-I disorder patients.
Baldessarini, R J; Salvatore, P; Khalsa, H-M K; Imaz-Etxeberria, H; Gonzalez-Pinto, A; Tohen, M
2012-01-01
Preliminary review of a century of studies of the course of manic-depressive syndromes produced 40 reports, of which approximately one-third report evidence of shortening wellness intervals or cycle-lengths with more recurrences, and two-thirds did not. We evaluated inter-episode intervals (cycle-length) in 128 clinically-treated, DSM-IV bipolar-I disorder patients followed prospectively and systematically over 5.7 years, with 6.5 episodes/person. As expected, cycle-length varied inversely with total cycle-count/person; however, multivariate linear regression found only longer initial hospitalization and fewer total cycles to be associated with cycle-length, whereas cycle-number (1, 2, 3, etc.), sex, intake-age, and first-episode polarity were not. Regression of within-subject cycle-length versus cycle-number yielded individual slope-functions with pseudo-random distribution (28% fell within ±1 month/cycle of the null [zero-slope]). Mean duration of early and late euthymic intervals (cycles 2 vs. 5) in patients with matched recurrence-counts was nearly identical. The course of bipolar-I disorder from onset was largely random or chaotic over nearly 6 years from onset. Only a minority of patients showed either cycle-acceleration or slowing, without changes in wellness intervals. The findings may be influenced by treatment-effects, but seem to indicate that most current bipolar-I disorder patients are unlikely to show progressive shortening of recurrence-cycles. Copyright © 2011 Elsevier B.V. All rights reserved.
Nuclear fuel cycle scenarios at CGNPC
International Nuclear Information System (INIS)
Xiao, Min; Zhou, Zhou; Nie, Li Hong; Mao, Guo Ping; Hao, Si Xiong; Shen, Kang
2008-01-01
Established in 1994, China Guangdong Nuclear Power Holding Co. (CGNPC) now owns two power stations GNPS and LNPS Phase I, with approximate 4000 MWe of installed capacity. With plant upgrades, advanced fuel management has been introduced into the two plants to improve the plant economical behavior with the high burnup fuel implemented. For the purpose of sustainable development, some preliminary studies on nuclear fuel cycle, especially on the back-end, have been carried out at CGNPC. According to the nuclear power development plan of China, the timing for operation and the capacity of the reprocessing facility are studied based on the amount of the spent fuel forecast in the future. Furthermore, scenarios of the fuel cycles in the future in China with the next generation of nuclear power were considered. Based on the international experiences on the spent fuel management, several options of spent fuel reprocessing strategies are investigated in detail, for example, MOX fuel recycling in light water reactor, especially in the current reactors of CGNPC, spent fuel intermediated storage, etc. All the investigations help us to draw an overall scheme of the nuclear fuel cycle, and to find a suitable road-map to achieve the sustainable development of nuclear power. (authors)
Advanced supersonic propulsion study, phases 3 and 4. [variable cycle engines
Allan, R. D.; Joy, W.
1977-01-01
An evaluation of various advanced propulsion concepts for supersonic cruise aircraft resulted in the identification of the double-bypass variable cycle engine as the most promising concept. This engine design utilizes special variable geometry components and an annular exhaust nozzle to provide high take-off thrust and low jet noise. The engine also provides good performance at both supersonic cruise and subsonic cruise. Emission characteristics are excellent. The advanced technology double-bypass variable cycle engine offers an improvement in aircraft range performance relative to earlier supersonic jet engine designs and yet at a lower level of engine noise. Research and technology programs required in certain design areas for this engine concept to realize its potential benefits include refined parametric analysis of selected variable cycle engines, screening of additional unconventional concepts, and engine preliminary design studies. Required critical technology programs are summarized.
Once-through thorium fuel cycle evaluation for TVA's Browns Ferry-3 Boiling Water Reactor
International Nuclear Information System (INIS)
Hopkins, G.C.
1982-05-01
This report documents benchmark evaluations to test thorium lattice predictive methods and neutron cross sections against available data and summarizes specific evaluations of the once-through thorium cycle when applied to the Browns Ferry-3 BWR. It was concluded that appreciable uncertainties in thorium cycle nuclear data cloud the ability to reliably predict the fuel cycle performance and that power reactor irradiations of ThO 2 rods in BWRs are desirable to resolve uncertainties. Benchmark evaluations indicated that the ENDF/B-IV data used in the evaluations should cause an underprediction of U-233/ThO 2 fuel reactivity, and, therefore, the results of the preliminary evaluations completed under the program should be conservative
Chaplin, W. J.; Jiménez-Reyes, S. J.; Eff-Darwich, A.; Elsworth, Y.; New, R.
2008-04-01
Frequencies, powers and damping rates of the solar p modes are all observed to vary over the 11-yr solar activity cycle. Here, we show that simultaneous variations in these parameters give rise to a subtle cross-talk effect, which we call the `devil in the detail', that biases p-mode frequencies estimated from analysis of long power frequency spectra. We also show that the resonant peaks observed in the power frequency spectra show small distortions due to the effect. Most of our paper is devoted to a study of the effect for Sun-as-a-star observations of the low-l p modes. We show that for these data the significance of the effect is marginal. We also touch briefly on the likely l dependence of the effect, and discuss the implications of these results for solar structure inversions.
Preliminary Safety Analysis Report for the Tokamak Physics Experiment
International Nuclear Information System (INIS)
Motloch, C.G.; Bonney, R.F.; Levine, J.D.; Masson, L.S.; Commander, J.C.
1995-04-01
This Preliminary Safety Analysis Report (PSAR), includes an indication of the magnitude of facility hazards, complexity of facility operations, and the stage of the facility life-cycle. It presents the results of safety analyses, safety assurance programs, identified vulnerabilities, compensatory measures, and, in general, the rationale describing why the Tokamak Physics Experiment (TPX) can be safely operated. It discusses application of the graded approach to the TPX safety analysis, including the basis for using Department of Energy (DOE) Order 5480.23 and DOE-STD-3009-94 in the development of the PSAR
Flower, Verity J. B.; Carn, Simon A.
2015-10-01
The identification of cyclic volcanic activity can elucidate underlying eruption dynamics and aid volcanic hazard mitigation. Whilst satellite datasets are often analysed individually, here we exploit the multi-platform NASA A-Train satellite constellation to cross-correlate cyclical signals identified using complementary measurement techniques at Soufriere Hills Volcano (SHV), Montserrat. In this paper we present a Multi-taper (MTM) Fast Fourier Transform (FFT) analysis of coincident SO2 and thermal infrared (TIR) satellite measurements at SHV facilitating the identification of cyclical volcanic behaviour. These measurements were collected by the Ozone Monitoring Instrument (OMI) and Moderate Resolution Imaging Spectroradiometer (MODIS) (respectively) in the A-Train. We identify a correlating cycle in both the OMI and MODIS data (54-58 days), with this multi-week feature attributable to episodes of dome growth. The 50 day cycles were also identified in ground-based SO2 data at SHV, confirming the validity of our analysis and further corroborating the presence of this cycle at the volcano. In addition a 12 day cycle was identified in the OMI data, previously attributed to variable lava effusion rates on shorter timescales. OMI data also display a one week (7-8 days) cycle attributable to cyclical variations in viewing angle resulting from the orbital characteristics of the Aura satellite. Longer period cycles possibly relating to magma intrusion were identified in the OMI record (102-, 121-, and 159 days); in addition to a 238-day cycle identified in the MODIS data corresponding to periodic destabilisation of the lava dome. Through the analysis of reconstructions generated from cycles identified in the OMI and MODIS data, periods of unrest were identified, including the major dome collapse of 20th May 2006 and significant explosive event of 3rd January 2009. Our analysis confirms the potential for identification of cyclical volcanic activity through combined
Selected pharmacokinetic parameters for cefovecin in hens and green iguanas
DEFF Research Database (Denmark)
Thuesen, Line Risager; Bertelsen, Mads Frost; Brimer, Leon
2009-01-01
hens and green iguanas, following subcutaneous injections with 10 mg cefovecin / kg bodyweight. Preliminary studies in eight additional species of birds and reptiles were performed and results were compared with the parameters found in hens and green iguanas. The kinetics were characterized by rapid...
International Nuclear Information System (INIS)
Leger, D.; Dinner, P.; Yoshida, H.
1991-01-01
Resulting from the Conceptual Design Activities (1988-1990) by the parties involved in the International Thermonuclear Experimental Reactor (ITER) project, this document summarizes the design requirements and the Conceptual Design Descriptions for each of the principal subsystems and design options of the ITER Fuel Cycle conceptual design. The ITER Fuel Cycle system provides for the handling of all tritiated water and gas mixtures on ITER. The system is subdivided into subsystems for fuelling, primary (torus) vacuum pumping, fuel processing, blanket tritium recovery, and common processes (including isotopic separation, fuel management and storage, and processes for detritiation of solid, liquid, and gaseous wastes). After an introduction describing system function and conceptual design procedure, a summary of the design is presented including a discussion of scope and main parameters, and the fuel design options for fuelling, plasma chamber vacuum pumping, fuel cleanup, blanket tritium recovery, and auxiliary and common processes. Design requirements are defined and design descriptions are given for the various subsystems (fuelling, plasma vacuum pumping, fuel cleanup, blanket tritium recovery, and auxiliary/common processes). The document ends with sections on fuel cycle design integration, fuel cycle building layout, safety considerations, a summary of the research and development programme, costing, and conclusions. Refs, figs and tabs
Gallagher, Rosemary; Damodaran, Harish; Werner, William G; Powell, Wendy; Deutsch, Judith E
2016-08-19
Evidence based virtual environments (VEs) that incorporate compensatory strategies such as cueing may change motor behavior and increase exercise intensity while also being engaging and motivating. The purpose of this study was to determine if persons with Parkinson's disease and aged matched healthy adults responded to auditory and visual cueing embedded in a bicycling VE as a method to increase exercise intensity. We tested two groups of participants, persons with Parkinson's disease (PD) (n = 15) and age-matched healthy adults (n = 13) as they cycled on a stationary bicycle while interacting with a VE. Participants cycled under two conditions: auditory cueing (provided by a metronome) and visual cueing (represented as central road markers in the VE). The auditory condition had four trials in which auditory cues or the VE were presented alone or in combination. The visual condition had five trials in which the VE and visual cue rate presentation was manipulated. Data were analyzed by condition using factorial RMANOVAs with planned t-tests corrected for multiple comparisons. There were no differences in pedaling rates between groups for both the auditory and visual cueing conditions. Persons with PD increased their pedaling rate in the auditory (F 4.78, p = 0.029) and visual cueing (F 26.48, p auditory (F = 24.72, p visual cueing (F = 40.69, p visual condition in age-matched healthy adults showed a step-wise increase in pedaling rate (p = 0.003 to p visual cues (p visual cues in order to obtain an increase in cycling intensity. The combination of the VE and auditory cues was neither additive nor interfering. These data serve as preliminary evidence that embedding auditory and visual cues to alter cycling speed in a VE as method to increase exercise intensity that may promote fitness.
MA-burners efficiency parameters allowing for the duration of transmutation process
International Nuclear Information System (INIS)
Gulevich, A.; Zemskov, E.; Kalugin, A.; Ponomarev, L.; Seliverstov, V.; Seregin, M.
2010-01-01
Transmutation of minor actinides (MA) means their transforming into the fission products. Usually, MA-burner's transmutation efficiency is characterized by the static parameters only, such as the number of neutrons absorbed and the rate of MA feeding. However, the proper characterization of MA-burner's efficiency additionally requires the consideration of parameters allowing for the duration of the MA transmutation process. Two parameters of that kind are proposed: a) transmutation time τ - mean time period from the moment a mass of MA is loaded into the burner's fuel cycle to be transmuted to the moment this mass is completely transmuted; b) number of reprocessing cycles n rep - effective number of reprocessing cycles a mass of loaded MA has to undergo before being completely transmuted. Some of MA-burners' types have been analyzed from the point of view of these parameters. It turned out that all of them have the value of parameters too high from the practical point of view. It appears that some new approaches to MA-burner's design have to be used to significantly reduce the value of these parameters in order to make the large-scale MA transmutation process practically reasonable. Some of such approaches are proposed and their potential efficiency is discussed. (authors)
Preliminary design and analysis on nuclear fuel cycle for fission-fusion hybrid spent fuel burner
International Nuclear Information System (INIS)
Chen Yan; Wang Minghuang; Jiang Jieqiong
2012-01-01
A wet-processing-based fuel cycle and a dry-processing were designed for a fission-fusion hybrid spent fuel burner (FDS-SFB). Mass flow of SFB was preliminarily analyzed. The feasibility analysis of initial loaded fuel inventory, recycle fuel fabrication and spent fuel reprocessing were preliminarily evaluated. The results of mass flow of FDS-SFB demonstrated that the initial loaded fuel inventory, recycle fuel fabrication and spent fuel reprocessing of nuclear fuel cycle of FDS-SFB is preliminarily feasible. (authors)
Annealing cycles and the self-organization of functionalized colloids
Dias, Cristóvão S.; Araújo, Nuno A. M.; Telo da Gama, Margarida M.
2018-01-01
The self-assembly of functionalized (patchy) particles with directional interactions into target structures is still a challenge, despite the significant experimental advances in their synthesis. Self-assembly pathways are typically characterized by high energy barriers that hinder access to stable (equilibrium) structures. A possible strategy to tackle this challenge is to perform annealing cycles. By periodically switching on and off the inter-particle bonds, one expects to smooth-out the kinetic pathways and favor the assembly of targeted structures. Preliminary results have shown that the efficiency of annealing cycles depends strongly on their frequency. Here, we study numerically how this frequency-dependence scales with the strength of the directional interactions (size of the patch σ). We use analytical arguments to show that the scaling results from the statistics of a random walk in configurational space.
Fast power cycle for fusion reactors
International Nuclear Information System (INIS)
Powell, J.; Fillo, J.; Makowitz, H.
1978-01-01
The unique, deep penetration capability of 14 MeV neutrons produced in DT fusion reactions allows the generation of very high temperature working fluid temperatures in a thermal power cycle. In the FAST (Fusion Augmented Steam Turbine) power cycle steam is directly superheated by the high temperature ceramic refractory interior of the blanket, after being generated by heat extracted from the relatively cool blanket structure. The steam is then passed to a high temperature gas turbine for power generation. Cycle studies have been carried out for a range of turbine inlet temperatures [1600 0 F to 3000 0 F (870 to 1650 0 C)], number of reheats, turbine mechanical efficiency, recuperator effectiveness, and system pressure losses. Gross cycle efficiency is projected to be in the range of 55 to 60%, (fusion energy to electric power), depending on parameters selected. Turbine inlet temperatures above 2000 0 F, while they do increase efficiency somewhat, are not necessarily for high cycle efficiency
Universality, marginal operators, and limit cycles
International Nuclear Information System (INIS)
Glazek, Stanislaw D.; Wilson, Kenneth G.
2004-01-01
The universality of renormalization-group limit-cycle behavior is illustrated with a simple discrete Hamiltonian model. A nonperturbative renormalization-group equation for the model is soluble analytically at criticality and exhibits one marginal operator (made necessary by the limit cycle) and an infinite set of irrelevant operators. Relevant operators are absent. The model exhibits an infinite series of bound-state energy eigenvalues. This infinite series approaches an exact geometric series as the eigenvalues approach zero--also a consequence of the limit cycle. Wegner's eigenvalues for irrelevant operators are calculated generically for all choices of parameters in the model. We show that Wegner's eigenvalues are independent of location on the limit cycle, in contrast with Wegner's operators themselves, which vary depending on their location on the limit cycle. An example is then used to illustrate numerically how one can tune the initial Hamiltonian to eliminate the first two irrelevant operators. After tuning, the Hamiltonian's bound-state eigenvalues converge much more quickly than otherwise to an exact geometric series
A hybrid mammalian cell cycle model
Directory of Open Access Journals (Sweden)
Vincent Noël
2013-08-01
Full Text Available Hybrid modeling provides an effective solution to cope with multiple time scales dynamics in systems biology. Among the applications of this method, one of the most important is the cell cycle regulation. The machinery of the cell cycle, leading to cell division and proliferation, combines slow growth, spatio-temporal re-organisation of the cell, and rapid changes of regulatory proteins concentrations induced by post-translational modifications. The advancement through the cell cycle comprises a well defined sequence of stages, separated by checkpoint transitions. The combination of continuous and discrete changes justifies hybrid modelling approaches to cell cycle dynamics. We present a piecewise-smooth version of a mammalian cell cycle model, obtained by hybridization from a smooth biochemical model. The approximate hybridization scheme, leading to simplified reaction rates and binary event location functions, is based on learning from a training set of trajectories of the smooth model. We discuss several learning strategies for the parameters of the hybrid model.
FLUOROETHERS AS A WORKING FLUIDS FOR LOW TEMPERATURE ORGANIC RANKINE CYCLE
Directory of Open Access Journals (Sweden)
Artemenko S.V
2014-12-01
Full Text Available Hydrofluoroethers as a new class of working fluids for the organic Rankine cycle have been considered to utilize the low-potential waste heat. Temperature range 300…400 K was chosen to provide energy conversion of waste heat from fuel cells. The direct assessment of the efficiency criteria for the Rankine cycle via artificial neural networks (ANN was used. To create ANN the critical parameters of substance and normal boiling temperature as input were chosen. The forecast of efficiency criteria for the Rankine cycle as output parameter which reproduces the coefficient of performance with high accuracy and without thermodynamic property calculations was presented.
Fabrication of preliminary fuel rods for SFR
International Nuclear Information System (INIS)
Kim, Sun Ki; Oh, Seok Jin; Ko, Young Mo; Woo, Youn Myung; Kim, Ki Hwan
2012-01-01
Metal fuels was selected for fueling many of the first reactors in the US, including the Experimental Breeder Reactor-I (EBR-I) and the Experimental Breeder Reactor-II (EBR-II) in Idaho, the FERMI-I reactor, and the Dounreay Fast Reactor (DFR) in the UK. Metallic U.Pu.Zr alloys were the reference fuel for the US Integral Fast Reactor (IFR) program. Metallic fuel has advantages such as simple fabrication procedures, good neutron economy, high thermal conductivity, excellent compatibility with a Na coolant and inherent passive safety. U-Zr-Pu alloy fuels have been used for SFR (sodium-cooled fast reactor) related to the closed fuel cycle for managing minor actinides and reducing a high radioactivity levels since the 1980s. Fabrication technology of metallic fuel for SFR has been in development in Korea as a national nuclear R and D program since 2007. For the final goal of SFR fuel rod fabrication with good performance, recently, three preliminary fuel rods were fabricated. In this paper, the preliminary fuel rods were fabricated, and then the inspection for QC(quality control) of the fuel rods was performed
International Nuclear Information System (INIS)
Tonoli, Celisa Caldana Costa; Vieira, Plinio Salmazo; Ward, Richard John; Arni, Raghuvir Krishnaswamy; Oliveira, Arthur Henrique Cavalcante de; Murakami, Mario Tyago
2009-01-01
Overexpression, purification, crystallization and preliminary X-ray diffraction analysis of the nucleoside diphosphate kinase b from Leishmania major are reported. The crystals belonged to the trigonal space group P3 2 21 and diffracted to 2.18 Å resolution. Nucleoside diphosphate kinases (NDKs; EC 2.7.4.6) play an essential role in the synthesis of nucleotides from intermediates in the salvage pathway in all parasitic trypanosomatids and their structural studies will be instrumental in shedding light on the biochemical machinery involved in the parasite life cycle and host–parasite interactions. In this work, NDKb from Leishmania major was overexpressed in Escherichia coli, purified to homogeneity and crystallized using the sitting-drop vapour-diffusion method. The NDK crystal diffracted to 2.2 Å resolution and belonged to the trigonal crystal system, with unit-cell parameters a = 114.2, c = 93.9 Å. Translation-function calculations yielded an unambiguous solution in the enantiomorphic space group P3 2 21
2D discontinuous piecewise linear map: Emergence of fashion cycles.
Gardini, L; Sushko, I; Matsuyama, K
2018-05-01
We consider a discrete-time version of the continuous-time fashion cycle model introduced in Matsuyama, 1992. Its dynamics are defined by a 2D discontinuous piecewise linear map depending on three parameters. In the parameter space of the map periodicity, regions associated with attracting cycles of different periods are organized in the period adding and period incrementing bifurcation structures. The boundaries of all the periodicity regions related to border collision bifurcations are obtained analytically in explicit form. We show the existence of several partially overlapping period incrementing structures, that is, a novelty for the considered class of maps. Moreover, we show that if the time-delay in the discrete time formulation of the model shrinks to zero, the number of period incrementing structures tends to infinity and the dynamics of the discrete time fashion cycle model converges to those of continuous-time fashion cycle model.
Burn cycle requirements comparison of pulsed and steady-state tokamak reactors
International Nuclear Information System (INIS)
Brooks, J.N.; Ehst, D.A.
1983-12-01
Burn cycle parameters and energy transfer system requirements were analyzed for an 8-m commercial tokamak reactor using four types of cycles: conventional, hybrid, internal transformer, and steady state. Not surprisingly, steady state is the best burn mode if it can be achieved. The hybrid cycle is a promising alternative to the conventional. In contrast, the internal transformer cycle does not appear attractive for the size tokamak in question
The cell cycle-regulated genes of Schizosaccharomyces pombe.
Oliva, Anna; Rosebrock, Adam; Ferrezuelo, Francisco; Pyne, Saumyadipta; Chen, Haiying; Skiena, Steve; Futcher, Bruce; Leatherwood, Janet
2005-07-01
Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast) and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast). The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.
ANALYSIS OF EXERGY PARAMETERS OF BIOGAS POWER PLANT
Directory of Open Access Journals (Sweden)
Denysova A.E.
2014-08-01
Full Text Available The techniques of an exergy analysis concerning various circuits of biogas units, which allows replacing traditional energy resources and improving environmental conditions, has been presented. The heat schemes of biogas units were proposed, and analysis of their effectiveness was made. The comparison of different cycle parameters of various biogas units (i.e. a combustion turbine unit, a combined cycle gas turbine unit with gas discharges into the boiler and a combined cycle gas turbine with a high-temperature vapor generator and a reheating stage was made, and the comparison of their exergy characteristics was carried out. The results of exergy analysis had demonstrated that the cycle of biogas CCGT (combined cycle gas turbine with a reheating stage and using a high-pressure steam generator is the most effective, that can be explained by the fact that the thermal energy proportions of combustion products, accounting for the steam cycle and the gas cycle are approximately equal, comparing to conventional combined cycle gas turbine units.
International Nuclear Information System (INIS)
Esteves, R.G.
1981-01-01
A simplified methodology for evaluating a reload safety cycle is presented. This methodology consists in selecting for each foreseen accident, the nuclear key reload safety parameters which determine the accident evolution. So, each key reload parameter is calculated and compared with its value for the first cycle. Those accidents, which have their key reload parameter bounded by the values of the first cycle do not need reanalise. Extension of the validity of this methodology when there exists change of fuel supplier is commented. (Author) [pt
Analysis of Maisotsenko open gas turbine bottoming cycle
International Nuclear Information System (INIS)
Saghafifar, Mohammad; Gadalla, Mohamed
2015-01-01
Maisotsenko gas turbine cycle (MGTC) is a recently proposed humid air turbine cycle. An air saturator is employed for air heating and humidification purposes in MGTC. In this paper, MGTC is integrated as the bottoming cycle to a topping simple gas turbine as Maisotsenko bottoming cycle (MBC). A thermodynamic optimization is performed to illustrate the advantages and disadvantages of MBC as compared with air bottoming cycle (ABC). Furthermore, detailed sensitivity analysis is reported to present the effect of different operating parameters on the proposed configurations' performance. Efficiency enhancement of 3.7% is reported which results in more than 2600 tonne of natural gas fuel savings per year. - Highlights: • Developed an accurate air saturator model. • Introduced Maisotsenko bottoming cycle (MBC) as a power generation cycle. • Performed Thermodynamic optimization for MBC and air bottoming cycle (ABC). • Performed detailed sensitivity analysis for MBC under different operating conditions. • MBC has higher efficiency and specific net work output as compared to ABC
On the approximation of the limit cycles function
Directory of Open Access Journals (Sweden)
L. Cherkas
2007-11-01
Full Text Available We consider planar vector fields depending on a real parameter. It is assumed that this vector field has a family of limit cycles which can be described by means of the limit cycles function $l$. We prove a relationship between the multiplicity of a limit cycle of this family and the order of a zero of the limit cycles function. Moreover, we present a procedure to approximate $l(x$, which is based on the Newton scheme applied to the Poincaré function and represents a continuation method. Finally, we demonstrate the effectiveness of the proposed procedure by means of a Liénard system.
Heteroclinic cycles between unstable attractors
International Nuclear Information System (INIS)
Broer, Henk; Efstathiou, Konstantinos; Subramanian, Easwar
2008-01-01
We consider networks of pulse coupled linear oscillators with non-zero delay where the coupling between the oscillators is given by the Mirollo–Strogatz function. We prove the existence of heteroclinic cycles between unstable attractors for a network of four oscillators and for an open set of parameter values
International Nuclear Information System (INIS)
Larionov, L.V.; Livshits, L.D.; Peresada, G.I.; AN SSSR, Moscow. Inst. Fiziki Zemli)
1985-01-01
Using the methods of piezo- and resistometry the influence of preliminary plastic deformation, phase transformation induced strengthening and heat treatment on kinetics of γ reversible α transformation in cerium is studied. It is shown, that the used methods of preliminary treatment of sample material do not change pressure value of γ → α and α →γ transformation initiation and do not affect hysteresis value, but affect considerably its kinetics. Preliminary plastic deformation and structural strengthening increase the average formation rate of a new phase. According to the data of tensile tests, structural strengthening, apprearing as a result of one cycle of γ → α → γ transformation, increases cerium strength characteristics 6y 30-50% with simultaneous decrease in plasticity. Metallographic studies confirm martensitic character of γ → α → γ transformations in cerium
Vinklárková, Bára; Chromý, Vratislav; Šprongl, Luděk; Bittová, Miroslava; Rikanová, Milena; Ohnútková, Ivana; Žaludová, Lenka
2015-01-01
To select a Kjeldahl procedure suitable for the determination of total protein in reference materials used in laboratory medicine, we reviewed in our previous article Kjeldahl methods adopted by clinical chemistry and found an indirect two-step analysis by total Kjeldahl nitrogen corrected for its nonprotein nitrogen and a direct analysis made on isolated protein precipitates. In this article, we compare both procedures on various reference materials. An indirect Kjeldahl method gave falsely lower results than a direct analysis. Preliminary performance parameters qualify the direct Kjeldahl analysis as a suitable primary reference procedure for the certification of total protein in reference laboratories.
Preliminary results on heavy flavor physics at SLD
Energy Technology Data Exchange (ETDEWEB)
Usher, T. [Stanford Univ., CA (United States)
1994-12-01
The author reports on preliminary heavy flavor physics results from the SLD detector at the SLAC Linear Collider. Efficient tagging of b{bar b} events is achieved with an impact parameter technique that takes advantage of the small and stable interaction point of the SLC and all charged tracks in Z{sup 0} decays. This technique is applied to samples of Z{sup 0} events collected during the 1992 and 1993 physics runs. Preliminary measurements of the ratio R{sub b} = {Gamma}(Z{sup 0} {yields} b{bar b})/{Gamma}(Z{sup 0} {yields} hadrons) and the average B hadron lifetime <{tau}{sub B}> are reported. In a sample of 27K Z{sup 0} events, values of R{sub b} = 0.235 {+-} 0.006(stat.) {+-} 0.018(syst.) and <{tau}{sub B}> = 1.53 {+-} 0.006(stat.) {+-} 0.018(syst.) are obtained. In addition, the first measurement of the left-right asymmetry A{sub b} is reported. Using a sample of 38K Z{sup 0} events with a luminosity weighted electron polarization of 62%, the author obtains a preliminary value of A{sub b} = 0.94 {+-} 0.006(stat.) {+-} 0.018(syst.).
Alebić, Miro Šimun; Stojanović, Nataša; Baldani, Dinka Pavičić; Duvnjak, Lea Smirčić
2016-12-01
This cross-sectional study aimed to investigate the association between menstrual cycle lenght and metabolic parameters in non-hyperandrogenic women with polycystic ovarian morphology, n = 250. Metabolic profiles of all participants were evaluated using anthropometric parameters (body mass index, waist circumference), parameters of dyslipidemia (total cholesterol, HDL-cholesterol, triglycerides) and markers of insulin resistance (fasting insulin, homeostasis model assessment for insulin resistance index). The associations between menstrual cycle lenght and cardiometabolic risk factors such as insulin resistance, dyslipidemia, and obesity were investigated. In non-hyperandrogenic women with polycystic ovarian morphology, menstrual cycle lenght was associated with hypertriglyceridemia and insulin resistance independently of body mass index. Moreover, menstrual cycle lenght added value to body mass index in predicting hypertriglyceridemia. The optimal menstrual cycle lenght cut-off value for identifying of non-hyperandrogenic women with polycystic ovarian morphology at metabolic risk was found to be 45 days. Metabolic profile of non-hyperandrogenic women with polycystic ovarian morphology (n = 75) with menstrual cycle lenght >45 days was similar to that of hyperandrogenic women with polycystic ovarian morphology (n = 138) while metabolic profile of non-hyperandrogenic women with polycystic ovarian morphology with menstrual cycle lenght ≤45 days (n = 112) was similar to that of controls (n = 167). Non-hyperandrogenic women with polycystic ovarian morphology with menstrual cycle lenght >45 days had higher prevalence of cardiometabolic risk factors compared to those with menstrual cycle lenght ≤45 days. Non-hyperandrogenic women with polycystic ovarian morphology are not metabolically homogeneous. Menstrual cycle lenght is an easy-to-obtain clinical parameter positively associated with the probability of unfavorable metabolic status in non
Directory of Open Access Journals (Sweden)
Salemović Duško R.
2015-01-01
Full Text Available In this paper preliminary design of device for finish cooling chocolate topping of biscuits in A.D. 'Jaffa'- Crvenka was done. The proposed preliminary design followed by the required technological process of finish cooling biscuits and required parameters of process which was supposed to get and which represented part of project task. Thermal analysis was made and obtained percentage error between surface contact of the air and chocolate topping, obtained from heat balance and geometrical over proposed preliminary design, wasn't more than 0.67%. This is a preliminary design completely justified because using required length of belt conveyor receive required temperature of chocolate topping at the end of the cooling process.
WISE/NEOWISE OBSERVATIONS OF THE JOVIAN TROJANS: PRELIMINARY RESULTS
International Nuclear Information System (INIS)
Grav, T.; Mainzer, A. K.; Bauer, J.; Masiero, J.; Eisenhardt, P. R. M.; Blauvelt, E.; DeBaun, E.; Elsbury, D.; Gautier, T. IV; Gomillion, S.; Hand, E.; Wilkins, A.; Spahr, T.; McMillan, R. S.; Walker, R.; Cutri, R.; Wright, E.
2011-01-01
We present the preliminary analysis of over 1739 known and 349 candidate Jovian Trojans observed by the NEOWISE component of the Wide-field Infrared Survey Explorer (WISE). With this survey the available diameters, albedos, and beaming parameters for the Jovian Trojans have been increased by more than an order of magnitude compared to previous surveys. We find that the Jovian Trojan population is very homogenous for sizes larger than ∼10 km (close to the detection limit of WISE for these objects). The observed sample consists almost exclusively of low albedo objects, having a mean albedo value of 0.07 ± 0.03. The beaming parameter was also derived for a large fraction of the observed sample, and it is also very homogenous with an observed mean value of 0.88 ± 0.13. Preliminary debiasing of the survey shows that our observed sample is consistent with the leading cloud containing more objects than the trailing cloud. We estimate the fraction to be N(leading)/N(trailing) ∼ 1.4 ± 0.2, lower than the 1.6 ± 0.1 value derived by Szabó et al.
Preliminary assessment of the environmental and health impacts of nuclear and coal fuel cycles
International Nuclear Information System (INIS)
Yang Yin; Chen Zhuzhou; Pan Ziqiang
1992-01-01
The paper reports on the environmental impacts and health effects of coal and nuclear fuel cycles in China. Data of interest for China are presented in a comparative manner; epidemiological investigations in Shanxi province indicate that the incidences of chronic pulmonary diseases and infant cogenital malformation were apparently increased over the fall-out areas of coal-fired power stations and coal mines. The authors outline the framework of a research project on environmental assessment of nuclear energy and other energy systems. The main features of the project are: environmental and health impacts of coal and nuclear fuel cycles, environmental impact assessment of coal transportation, cost accounting of nuclear and other energy sources, health risk assessment. (author). 24 refs, 4 tabs
Directory of Open Access Journals (Sweden)
M. Di Stefano
2013-01-01
Full Text Available The aim of this preliminary research is to investigate the reliability of a new qualitative parameter, called Trabecular Bone Score (TBS, recently proposed for evaluating the microarchitectural arrangement of cancellous bone in scans carried out by dual energy X-ray absorptiometry (DXA. Vertebral bodies of 15 fresh samples of lumbar spines of adult pig were analysed either in basal conditions and with altered microarchitecture of the cancellous bone obtained by progressive drilling. The examined bony areas do not show changes in bone mineral density (BMD, whereas TBS values decrease with the increasing alteration of the vertebral microtrabecular structure. Our preliminary data seem to confirm the reliability of TBS as a qualitative parameter useful for evaluating the microarchitectural strength in bony areas quantitatively analysed by DXA.
AI-guided parameter optimization in inverse treatment planning
International Nuclear Information System (INIS)
Yan Hui; Yin Fangfang; Guan Huaiqun; Kim, Jae Ho
2003-01-01
An artificial intelligence (AI)-guided inverse planning system was developed to optimize the combination of parameters in the objective function for intensity-modulated radiation therapy (IMRT). In this system, the empirical knowledge of inverse planning was formulated with fuzzy if-then rules, which then guide the parameter modification based on the on-line calculated dose. Three kinds of parameters (weighting factor, dose specification, and dose prescription) were automatically modified using the fuzzy inference system (FIS). The performance of the AI-guided inverse planning system (AIGIPS) was examined using the simulated and clinical examples. Preliminary results indicate that the expected dose distribution was automatically achieved using the AI-guided inverse planning system, with the complicated compromising between different parameters accomplished by the fuzzy inference technique. The AIGIPS provides a highly promising method to replace the current trial-and-error approach
Leptin and its potential interest in assisted reproduction cycles.
Catteau, A; Caillon, H; Barrière, P; Denis, M G; Masson, D; Fréour, T
2016-04-01
Leptin, an adipose hormone, has been shown to control energy homeostasis and food intake, and exert many actions on female reproductive function. Consequently, this adipokine is a pivotal factor in studies conducted on animal models and humans to decipher the mechanisms behind the infertility often observed in obese women. A systematic PubMed search was conducted on all articles, published up to January 2015 and related to leptin and its actions on energy balance and reproduction, using the following key words: leptin, reproduction, infertility, IVF and controlled ovarian stimulation. The available literature was reviewed in order to provide an overview of the current knowledge on the physiological roles of leptin, its involvement in female reproductive function and its potential interest as a prognostic marker in IVF cycles. Animal and human studies show that leptin communicates nutritional status to the central nervous system and emerging evidence has demonstrated that leptin is involved in the control of reproductive functions by acting both directly on the ovaries and indirectly on the central nervous system. With respect to the clinical use of leptin as a biomarker in IVF cycles, a systematic review of the literature suggested its potential interest as a predictor of IVF outcome, as high serum and/or follicular fluid leptin concentrations have correlated negatively with cycle outcome. However, these preliminary results remain to be confirmed. Leptin regulates energy balance and female reproductive function, mainly through its action on hypothalamic-pituitary-ovarian function, whose molecular and cellular aspects are progressively being deciphered. Preliminary studies evaluating leptin as a biomarker in human IVF seem promising but need further confirmation. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Investigation of Cycle-to-Cycle Variability of NO in Homogeneous Combustion
Directory of Open Access Journals (Sweden)
Karvountzis-Kontakiotis A.
2015-01-01
Full Text Available Cyclic variability of spark ignition engines is recognized as a scatter in the combustion parameter recordings during actual operation in steady state conditions. Combustion variability may occur due to fluctuations in both early flame kernel development and in turbulent flame propagation with an impact on fuel consumption and emissions. In this study, a detailed chemistry model for the prediction of NO formation in homogeneous engine conditions is presented. The Wiebe parameterization is used for the prediction of heat release; then the calculated thermodynamic data are fed into the chemistry model to predict NO evolution at each degree of crank angle. Experimental data obtained from literature studies were used to validate the mean NO levels calculated. Then the model was applied to predict the impact of cyclic variability on mean NO and the amplitude of its variation. The cyclic variability was simulated by introducing random perturbations, which followed a normal distribution, to the Wiebe function parameters. The results of this approach show that the model proposed better predicts mean NO formation than earlier methods. Also, it shows that to the non linear formation rate of NO with temperature, cycle-to-cycle variation leads to higher mean NO emission levels than what one would predict without taking cyclic variation into account.
New insight into regenerated air heat pump cycle
International Nuclear Information System (INIS)
Zhang, Chun-Lu; Yuan, Han; Cao, Xiang
2015-01-01
Regenerated air (reverse Brayton) cycle has unique potentials in heat pump applications compared to conventional vapor-compression cycles. To better understand the regenerated air heat pump cycle characteristics, a thermodynamic model with new equivalent parameters was developed in this paper. Equivalent temperature ratio and equivalent isentropic efficiency of expander were introduced to represent the effect of regenerator, which made the regenerated air cycle in the same mathematical expressions as the basic air cycle and created an easy way to prove some important features that regenerated air cycle inherits from the basic one. Moreover, we proved in theory that the regenerator does not always improve the air cycle efficiency. Larger temperature ratio and lower effectiveness of regenerator could make the regenerated air cycle even worse than the basic air cycle. Lastly, we found that only under certain conditions the cycle could get remarkable benefits from a well-sized regenerator. These results would enable further study of the regenerated air cycle from a different perspective. - Highlights: • A thermodynamic model for regenerated air heat pump cycle was developed. • Equivalent temperature ratio and equivalent expander efficiency were introduced. • We proved regenerated air cycle can make heating capacity in line with heating load. • We proved the regenerator does not always improve the air cycle efficiency.
Optimization of MOX fuel cycles in pebble bed HTGR
International Nuclear Information System (INIS)
Wei Jinfeng; Li Fu; Sun Yuliang
2013-01-01
Compared with light water reactor (LWR), the pebble bed high temperature gas-cooled reactor (HTGR) is able to operate in a full mixed oxide (MOX) fuelled core without significant change to core structure design. Based on a reference design of 250 MW pebble bed HTGR, four MOX fuel cycles were designed and evaluated by VSOP program package, including the mixed Pu-U fuel pebbles and mixed loading of separate Pu-pebbles and U-pebbles. Some important physics features were investigated and compared for these four cycles, such as the effective multiplication factor of initial core, the pebble residence time, discharge burnup, and temperature coefficients. Preliminary results show that the overall performance of one case is superior to other equivalent MOX fuel cycles on condition that uranium fuel elements and plutonium fuel elements are separated as the different fuel pebbles and that the uranium fuel elements are irradiated longer in the core than the plutonium fuel elements, and the average discharge burnup of this case is also higher than others. (authors)
Performance Analysis of Hybrid Electric Vehicle over Different Driving Cycles
Panday, Aishwarya; Bansal, Hari Om
2017-02-01
Article aims to find the nature and response of a hybrid vehicle on various standard driving cycles. Road profile parameters play an important role in determining the fuel efficiency. Typical parameters of road profile can be reduced to a useful smaller set using principal component analysis and independent component analysis. Resultant data set obtained after size reduction may result in more appropriate and important parameter cluster. With reduced parameter set fuel economies over various driving cycles, are ranked using TOPSIS and VIKOR multi-criteria decision making methods. The ranking trend is then compared with the fuel economies achieved after driving the vehicle over respective roads. Control strategy responsible for power split is optimized using genetic algorithm. 1RC battery model and modified SOC estimation method are considered for the simulation and improved results compared with the default are obtained.
Energy Conversion Advanced Heat Transport Loop and Power Cycle
Energy Technology Data Exchange (ETDEWEB)
Oh, C. H.
2006-08-01
The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and an 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to various
Energy Technology Data Exchange (ETDEWEB)
Bae, Yoon Yeong; Park, Jong Kyun; Cho, Bong Hyun and others
2006-01-15
This research has been performed to introduce a concept of supercritical pressure water cooled reactor(SCWR) in Korea The area of research includes core conceptual design, evaluation of candidate fuel, fluid systems conceptual design with mechanical consideration, preparation of safety analysis code, and construction of supercritical pressure heat transfer test facility, SPHINX, and preliminary test. As a result of the research, a set of tools for the reactor core design has been developed and the conceptual core design with solid moderator was proposed. The direct thermodynamic cycle has been studied to find a optimum design. The safety analysis code has also been adapted to supercritical pressure condition. A supercritical pressure CO2 heat transfer test facility has been constructed and preliminary test proved the facility works as expected. The result of this project will be good basis for the participation in the international collaboration under GIF GEN-IV program and next 5-year mid and long term nuclear research program of MOST. The heat transfer test loop, SPHINX, completed as a result of this project may be used for the power cycle study as well as further heat transfer study for the various geometries.
Variable Cycle Engine Technology Program Planning and Definition Study
Westmoreland, J. S.; Stern, A. M.
1978-01-01
The variable stream control engine, VSCE-502B, was selected as the base engine, with the inverted flow engine concept selected as a backup. Critical component technologies were identified, and technology programs were formulated. Several engine configurations were defined on a preliminary basis to serve as demonstration vehicles for the various technologies. The different configurations present compromises in cost, technical risk, and technology return. Plans for possible variably cycle engine technology programs were formulated by synthesizing the technology requirements with the different demonstrator configurations.
Study on thermodynamic cycle of high temperature gas-cooled reactor
International Nuclear Information System (INIS)
Qu Xinhe; Yang Xiaoyong; Wang Jie
2017-01-01
The development trend of the (very) High temperature gas-cooled reactor is to gradually increase the reactor outlet temperature. The different power conversion units are required at the different reactor outlet temperature. In this paper, for the helium turbine direct cycle and the combined cycle of the power conversion unit of the High temperature gas-cooled reactor, the mathematic models are established, and three cycle plans are designed. The helium turbine direct cycle is a Brayton cycle with recuperator, precooler and intercooler. In the combined cycle plan 1, the topping cycle is a simple Brayton cycle without recuperator, precooler and intercooler, and the bottoming cycle is based on the steam parameters (540deg, 6 MPa) recommended by Siemens. In the combined cycle plan 2, the topping cycle also is a simple Brayton cycle, and the bottoming cycle which is a Rankine cycle with reheating cycle is based on the steam parameters of conventional subcritical thermal power generation (540degC, 18 MPa). The optimization results showed that the cycle efficiency of the combined cycle plan 2 is the highest, the second is the helium turbine direct cycle, and the combined cycle plan 2 is the lowest. When the reactor outlet temperature is 900degC and the pressure ratio is 2.02, the cycle efficiency of the combined cycle plan 2 can reach 49.7%. The helium turbine direct cycle has a reactor inlet temperature above 500degC due to the regenerating cycle, so it requires a cooling circuit for the internal wall of the reactor pressure vessel. When the reactor outlet temperature increases, the increase of the pressure ratio required by the helium turbine direct cycle increases may bring some difficulties to the design and manufacture of the magnetic bearings. For the combined cycle, the reactor inlet temperature can be controlled below than 370degC, so the reactor pressure vessel can use SA533 steel without cooling the internal wall of the reactor pressure vessel. The pressure
Methodology for kinematic cycle characterization of vehicles with fixed routes in urban areas
Jiménez Alonso, Felipe; Román de Andrés, Alfonso; López Martínez, José María
2013-01-01
This paper analyses the driving cycles of a fleet of vehicles with predetermined urban itineraries. Most driving cycles developed for such type of vehicles do not properly address variability among itineraries. Here we develop a polygonal driving cycle that assesses each group of related routes, based on microscopic parameters. It measures the kinematic cycles of the routes traveled by the vehicle fleet, segments cycles into micro-cycles, and characterizes their properties, groups them int...
Selgrade, J F; Harris, L A; Pasteur, R D
2009-10-21
This study presents a 13-dimensional system of delayed differential equations which predicts serum concentrations of five hormones important for regulation of the menstrual cycle. Parameters for the system are fit to two different data sets for normally cycling women. For these best fit parameter sets, model simulations agree well with the two different data sets but one model also has an abnormal stable periodic solution, which may represent polycystic ovarian syndrome. This abnormal cycle occurs for the model in which the normal cycle has estradiol levels at the high end of the normal range. Differences in model behavior are explained by studying hysteresis curves in bifurcation diagrams with respect to sensitive model parameters. For instance, one sensitive parameter is indicative of the estradiol concentration that promotes pituitary synthesis of a large amount of luteinizing hormone, which is required for ovulation. Also, it is observed that models with greater early follicular growth rates may have a greater risk of cycling abnormally.
Social Cost Assessment for Nuclear Fuel Cycle Options in the Republic of Korea
Energy Technology Data Exchange (ETDEWEB)
Joo, Ji-eun; Yim, Man-Sung [KAIST, Daejeon (Korea, Republic of)
2016-10-15
This paper will investigate the vast array of economic factors to estimate the true cost of the nuclear power. There are many studies addressing the external costs of energy production. However, it is only since the 1990s that the external costs of nuclear powered electricity production has been studied in detail. Each investigation has identified their own set of external costs and developed formulas and models using a variety of statistical techniques. The objective of this research is to broaden the scope of the parameters currently consider by adding new areas and expanding on the types of situations considered. Previously the approach to evaluating the external cost of nuclear power did not include various fuel cycle options and influencing parameters. Cost has always been a very important factor in decision-making, in particular for policy choices evaluating the alternative energy sources and electricity generation technologies. Assessment of external costs in support of decision-making should reflect timely consideration of important country specific policy objective. PWR-MOX and FR-Pyro are the best fuel cycle in parameter of environment impacts, but OT or OT-ER is proper than FR-Pyro in human beings. Using the OT fuel cycle is better than FR-Pyro to reduce the conflict cost. When energy supply is deficient, FR-Pyro fuel cycle stands longer than other fuel cycles. Proliferation resistance is shown as 'high' in all fuel cycles, so there are no difference between fuel cycles. When the severe accident occurs, FR-Pyro cycle is economical than other OT based fuel cycles.
MA-burners efficiency parameters allowing for the duration of transmutation process
Energy Technology Data Exchange (ETDEWEB)
Gulevich, A.; Zemskov, E. [Institute of Physics and Power Engineering, Bondarenko Square 1, Obninsk, Kaluga Region 249020 (Russian Federation); Kalugin, A.; Ponomarev, L. [Russian Research Center ' ' Kurchatov Institute' ' Kurchatov Square 1, Moscow 123182 (Russian Federation); Seliverstov, V. [Institute of Theoretical and Experimental Physics ul.B. Cheremushkinskaya 25, Moscow 117259 (Russian Federation); Seregin, M. [Russian Research Institute of Chemical Technology Kashirskoe Shosse 33, Moscow 115230 (Russian Federation)
2010-07-01
Transmutation of minor actinides (MA) means their transforming into the fission products. Usually, MA-burner's transmutation efficiency is characterized by the static parameters only, such as the number of neutrons absorbed and the rate of MA feeding. However, the proper characterization of MA-burner's efficiency additionally requires the consideration of parameters allowing for the duration of the MA transmutation process. Two parameters of that kind are proposed: a) transmutation time {tau} - mean time period from the moment a mass of MA is loaded into the burner's fuel cycle to be transmuted to the moment this mass is completely transmuted; b) number of reprocessing cycles n{sub rep} - effective number of reprocessing cycles a mass of loaded MA has to undergo before being completely transmuted. Some of MA-burners' types have been analyzed from the point of view of these parameters. It turned out that all of them have the value of parameters too high from the practical point of view. It appears that some new approaches to MA-burner's design have to be used to significantly reduce the value of these parameters in order to make the large-scale MA transmutation process practically reasonable. Some of such approaches are proposed and their potential efficiency is discussed. (authors)
International Nuclear Information System (INIS)
Ostenak, C.A.; Whitty, W.J.; Dietz, R.J.
1979-11-01
Preliminary concepts of materials accountability are presented for an internationally safeguarded nuclear-waste geologic repository. A hypothetical reference repository that receives nuclear waste for emplacement in a geologic medium serves to illustrate specific safeguards concepts. Nuclear wastes received at the reference repository derive from prior fuel-cycle operations. Alternative safeguards techniques ranging from item accounting to nondestructive assay and waste characteristics that affect the necessary level of safeguards are examined. Downgrading of safeguards prior to shipment to the repository is recommended whenever possible. The point in the waste cycle where international safeguards may be terminate depends on the fissile content, feasibility of separation, and practicable recoverability of the waste: termination may not be possible if spent fuels are declared as waste
International Nuclear Information System (INIS)
Ahmadi, Mohammad H.; Mohammadi, Amir H.; Dehghani, Saeed
2013-01-01
Highlights: • The optimal power of an endoreversible Stirling cycle is investigated. • In the endoreversible cycle, external heat transfer processes are considered irreversible. • Optimal temperature of the heat source leading to a maximum power for the cycle is detained. • Effect of design parameters on the power and its corresponding thermal efficiency is studied. - Abstract: In this communication, the optimal power of an endoreversible Stirling cycle with perfect regeneration is investigated. In the endoreversible cycle, external heat transfer processes are irreversible. Optimal temperature of the heat source leading to a maximum power for the cycle is detained. Moreover, effect of design parameters of the Stirling engine on the maximized power of the engine and its corresponding thermal efficiency is studied
Preliminary study of S-CO{sub 2} cycle control logic for part load operation
Energy Technology Data Exchange (ETDEWEB)
Ahn, Yoonhan; Lee, Jeong Ik [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)
2016-05-15
The benefits of S-CO{sub 2} cycle are relatively high efficiency under the mild turbine inlet temperature region, simple layout configuration and small foot-print. In addition, the safety of the SFR system can be inherently enhanced as the violent sodium-water reaction can be substituted with the mild sodium-CO{sub 2} reaction. 75MWe S-CO{sub 2} recompression cycle with radial type turbomachineries and PCHE was designed. Under various part load conditions (30-100% thermal load), off-design performance of the designed system was assessed, and different control logics were first tested. It was identified that the inventory control strategy is the most efficient logic for the part load operation. In the system operation, the compressor surge condition is seriously considered and controlled to avoid the system damage.
International Nuclear Information System (INIS)
Madhurantakam, Chaithanya; Nilsson, Ola B.; Jönsson, Klas; Grönlund, Hans; Achour, Adnane
2009-01-01
The recombinant form of the allergen Can f 2 from C. familiaris was produced, isolated and crystallized in two different forms. Preliminary X-ray diffraction analyses are reported for the two crystal forms of Can f 2. The allergen Can f 2 from dog (Canis familiaris) present in saliva, dander and fur is an important cause of allergic sensitization worldwide. Here, the production, isolation, crystallization and preliminary X-ray diffraction analysis of two crystal forms of recombinant Can f 2 are reported. The first crystal form belonged to space group C222, with unit-cell parameters a = 68.7, b = 77.3, c = 65.1 Å, and diffracted to 1.55 Å resolution, while the second crystal form belonged to space group C2, with unit-cell parameters a = 75.7, b = 48.3, c = 68.7 Å, β = 126.5°, and diffracted to 2.1 Å resolution. Preliminary data analysis indicated the presence of a single molecule in the asymmetric unit for both crystal forms
Bottoming micro-Rankine cycles for micro-gas turbines
International Nuclear Information System (INIS)
Invernizzi, Costante; Iora, Paolo; Silva, Paolo
2007-01-01
This paper investigates the possibility of enhancing the performances of micro-gas turbines through the addition of a bottoming organic Rankine cycle which recovers the thermal power of the exhaust gases typically available in the range of 250-300 o C. The ORC cycles are particularly suitable for the recovery of heat from sources at variable temperatures, and for the generation of medium to small electric power. With reference to a micro-gas turbine with a size of about 100 kWe, a combined configuration could increase the net electric power by about 1/3, yielding an increase of the electrical efficiency of up to 40%. A specific analysis of the characteristics of different classes of working fluids is carried out in order to define a procedure to select the most appropriate fluid, capable of satisfying both environmental (ozone depletion potential, global warming potential) and technical (flammability, toxicity, fluid critical temperature and molecular complexity) concerns. Afterwards, a thermodynamic analysis is performed to ascertain the most favourable cycle thermodynamic conditions, from the point of view of heat recovery. Furthermore, a preliminary design of the ORC turbine (number of stages, outer diameter and rotational speed) is carried out
Preliminary RAMI analysis of WCLL blanket and breeder systems
International Nuclear Information System (INIS)
Arroyo, Jose Manuel; Brown, Richard; Harman, Jon; Rosa, Elena; Ibarra, Angel
2015-01-01
Highlights: • Preliminary RAMI model for WCLL has been developed. • Critical parts and parameters influencing WCLL availability have been focused. • Necessary developments of tools/models to represent system performance have been identified. - Abstract: DEMO will be a prototype fusion reactor designed to prove the capability to produce electrical power in a commercially acceptable way. One of the key factors in that endeavor is the achievement of certain level of plant availability. Therefore, RAMI (Reliability, Availability, Maintainability and Inspectability) will be a key element in the engineering development of DEMO. Some studies have been started so as to develop the tools and models to assess different design alternatives from RAMI point of view. The main objective of these studies is to be able to evaluate the influence of different parameters on DEMO availability and to focus the critical parts that should be further researched and improved in order to develop a high-availability oriented DEMO design. A preliminary RAMI analysis of the Water Cooled Lithium-Lead (WCLL) blanket and breeder concept for DEMO has been developed. The amounts of single elements that may fail (e.g. more than 180,000 C-shaped tubes) and the mean down time associated to failures inside the vacuum vessel (around 3 months) have been highlighted as the critical parameters influencing the system availability. On the other hand, the necessary developments of tools/models to better represent the system performance have been identified and proposed for future work.
Preliminary RAMI analysis of WCLL blanket and breeder systems
Energy Technology Data Exchange (ETDEWEB)
Arroyo, Jose Manuel, E-mail: josemanuel.arroyo@ciemat.es [Laboratorio Nacional de Fusión por Confinamiento Magnético – CIEMAT, Madrid (Spain); Brown, Richard [Culham Centre for Fusion Energy, Culham Science Centre, Abingdon (United Kingdom); Harman, Jon [EFDA Close Support Unit, Garching (Germany); Rosa, Elena; Ibarra, Angel [Laboratorio Nacional de Fusión por Confinamiento Magnético – CIEMAT, Madrid (Spain)
2015-10-15
Highlights: • Preliminary RAMI model for WCLL has been developed. • Critical parts and parameters influencing WCLL availability have been focused. • Necessary developments of tools/models to represent system performance have been identified. - Abstract: DEMO will be a prototype fusion reactor designed to prove the capability to produce electrical power in a commercially acceptable way. One of the key factors in that endeavor is the achievement of certain level of plant availability. Therefore, RAMI (Reliability, Availability, Maintainability and Inspectability) will be a key element in the engineering development of DEMO. Some studies have been started so as to develop the tools and models to assess different design alternatives from RAMI point of view. The main objective of these studies is to be able to evaluate the influence of different parameters on DEMO availability and to focus the critical parts that should be further researched and improved in order to develop a high-availability oriented DEMO design. A preliminary RAMI analysis of the Water Cooled Lithium-Lead (WCLL) blanket and breeder concept for DEMO has been developed. The amounts of single elements that may fail (e.g. more than 180,000 C-shaped tubes) and the mean down time associated to failures inside the vacuum vessel (around 3 months) have been highlighted as the critical parameters influencing the system availability. On the other hand, the necessary developments of tools/models to better represent the system performance have been identified and proposed for future work.
International Nuclear Information System (INIS)
Wang Jiangfeng; Sun Zhixin; Dai Yiping; Ma Shaolin
2010-01-01
Supercritical CO 2 power cycle shows a high potential to recover low-grade waste heat due to its better temperature glide matching between heat source and working fluid in the heat recovery vapor generator (HRVG). Parametric analysis and exergy analysis are conducted to examine the effects of thermodynamic parameters on the cycle performance and exergy destruction in each component. The thermodynamic parameters of the supercritical CO 2 power cycle is optimized with exergy efficiency as an objective function by means of genetic algorithm (GA) under the given waste heat condition. An artificial neural network (ANN) with the multi-layer feed-forward network type and back-propagation training is used to achieve parametric optimization design rapidly. It is shown that the key thermodynamic parameters, such as turbine inlet pressure, turbine inlet temperature and environment temperature have significant effects on the performance of the supercritical CO 2 power cycle and exergy destruction in each component. It is also shown that the optimum thermodynamic parameters of supercritical CO 2 power cycle can be predicted with good accuracy using artificial neural network under variable waste heat conditions.
Van Dyke, Michael B.
2013-01-01
Present preliminary work using lumped parameter models to approximate dynamic response of electronic units to random vibration; Derive a general N-DOF model for application to electronic units; Illustrate parametric influence of model parameters; Implication of coupled dynamics for unit/board design; Demonstrate use of model to infer printed wiring board (PWB) dynamics from external chassis test measurement.
International Nuclear Information System (INIS)
Avenhaus, R.; Heil, J.
1979-01-01
In this paper analyses are made of the values of those parameters that characterize the present safeguards system that is applied to a national fuel cycle; those values have to be fixed quantitatively so that all actions of the safeguards authority are specified precisely. The analysis starts by introducing three categories of quantities: The design parameters (number of MBAs, inventory frequency, variance of MUF, verification effort and false-alarm probability) describe those quantities whose values have to be specified before the safeguards system can be implemented. The performance criteria (probability of detection, expected detection time, goal quantity) measure the effectiveness of a safeguards system; and the standards (threshold amount and critical time) characterize the magnitude of the proliferation problem. The means by which the values of the individual design parameters can be determined with the help of the performance criteria; which qualitative arguments can narrow down the arbitrariness of the choice of values of the remaining parameters; and which parameter values have to be fixed more or less arbitrarily, are investigated. As a result of these considerations, which include the optimal allocation of a given inspection effort, the problem of analysing the structure of the safeguards system is reduced to an evaluation of the interplay of only a few parameters, essentially the quality of the measurement system (variance of MUF), verification effort, false-alarm probability, goal quantity and probability of detection
Dual-pressure vaporization Kalina cycle for cascade reclaiming heat resource for power generation
International Nuclear Information System (INIS)
Guo, Zhanwei; Zhang, Zhi; Chen, Yaping; Wu, Jiafeng; Dong, Cong
2015-01-01
Graphical abstract: Schematic of the dual-pressure evaporation Kalina cycle. - Highlights: • Dual-pressure vaporization Kalina cycle for high-grade heat resource is investigated. • It is designed with 2nd evaporation branch for cascade utilization of heat resource. • Work and basic concentrations, dew point temperature of evaporation are optimized. • Power recovery efficiency of proposed cycle is 17% higher than that of Kalina cycle. • Dual-p vaporization Kalina cycle fits reclaiming heat resource higher than 350 °C. - Abstract: To further improve the cycle efficiency with the heat transfer curves between higher than 350 °C heat resource and the evaporating working medium of the Kalina cycle and to reduce the exhaust temperature of heat resource, the dual-pressure vaporization Kalina cycle for cascade utilization of high-to-mid grade heat resource is proposed. The optimization was conducted for parameters in this modified Kalina cycle such as concentrations of work solution and basic solution, evaporation dew point temperature. Under the conditions of inlet temperatures of heat resource and cooling water of respectively 400 °C and 25 °C and the constraints of proper heat transfer pinch point temperature differences, the maximum evaporation pressure not exceeds 20 MPa, the vapour quality at the turbine outlet is greater than 0.85 and the exhaust temperature of heat resource is not lower than 90 °C, the optimum parameters are obtained that the work and basic concentrations are 0.45 and 0.272 respectively, the dew point temperature of evaporation is 300 °C, and the corresponding power recovery efficiency of the dual-pressure vaporization Kalina cycle reaches 27%, which is 17% higher than that of the Kalina cycle with optimum parameters.
International Nuclear Information System (INIS)
Zheng Danxing; Meng Xuelin
2012-01-01
Highlights: ► Two novel fundamental concepts of the absorption refrigeration cycle were proposed. ► The interaction mechanism of compressor pressure increasing with other key-parameters was investigated. ► A set of optimal operating condition of hybrid refrigeration cycle was found. ► A simulation and investigation for R134a-DMF hybrid refrigeration cycle was performed. - Abstract: The absorption–compression hybrid refrigeration cycle has been considered as an effective approach to reduce the mechanical work consumption by using low-grade heat, such as solar energy. This work aims at studying the thermodynamic mechanism of the hybrid refrigeration cycle. Two fundamental concepts have been proposed, which are the ultimate refrigerating temperature (or the ultimate temperature lift) and the behavior turning. On the basis of that, the interaction mechanism of compressor pressure increasing with other key-parameters and the impact of compressor pressure increasing on the cycle performance have been investigated. The key-parameters include the concentration difference, the circulation ratio of working fluid, etc. The work points out that the hybrid refrigeration cycle performance varies with the change of compressor outlet pressure and depends on which one achieves dominance in the hybrid refrigeration cycle, the absorption sub-system or the compression sub-system. The behavior turning point during parameters changing corresponds to a maximum value of the heat powered coefficient of performance. In this case, the hybrid refrigeration cycle performance is optimal because the low-grade heat utilization is the most effective. In addition, to validate the theoretical analysis, a solar hybrid refrigeration cycle with R134a–DMF as working pair was simulated. The Peng–Robinson equation of state was adopted to calculate thermophysical properties when the reliability assessment of the prediction models on the available literature data of R134a–DMF system had been
International Nuclear Information System (INIS)
Wang, Xing; Liu, Xiaomin; Zhang, Chuhua
2014-01-01
Highlights: • Optimal level constitution of parameters for ORC system was obtained. • Order of system parameters’ sensitivity to the performance of ORC was revealed. • Evaporating temperature had significant effect on performance of ORC system. • Superheater had little effect on performance of ORC system. - Abstract: In this study, a thermodynamic model of Organic Rankine Cycle (ORC) system combined with orthogonal design is proposed. The comprehensive scoring method was adopted to obtain a comprehensive index to evaluate both of the thermodynamic performance and economic performance. The optimal level constitution of system parameters which improves the thermodynamic and economic performance of ORC system is provided by analyzing the result of orthogonal design. The range analysis based on orthogonal design is adopted to determine the sensitivity of system parameters to the net power output of ORC system, thermal efficiency, the SP factor of radial inflow turbine, the power decrease factor of the pump and the total heat transfer capacity. The results show that the optimal level constitution of system parameters is determined as the working fluid of R245fa, the super heating temperature of 10 °C, the pinch temperature difference in evaporator and condenser of 5 °C, the evaporating temperature of 65 °C, the isentropic efficiency for the pump of 0.75 and the isentropic efficiency of radial inflow turbine of 0.85. The order of system parameters’ sensitivity to the comprehensive index of orthogonal design is evaporating temperature > isentropic efficiency of radial inflow turbine > the working fluid > the pinch temperature difference of the evaporator and the condenser > isentropic efficiency of cycle pump > the super heating temperature. This study provides useful references for selecting main controlled parameters in the optimal design of ORC system
Energy Technology Data Exchange (ETDEWEB)
1981-11-01
Program accomplishments in a continuing effort to demonstrate the feasibility of direct coal-fired, closed-cycle MHD power generation are reported. This volume contains the following appendices: (A) user's manual for 2-dimensional MHD generator code (2DEM); (B) performance estimates for a nominal 30 MW argon segmented heater; (C) the feedwater cooled Brayton cycle; (D) application of CCMHD in an industrial cogeneration environment; (E) preliminary design for shell and tube primary heat exchanger; and (F) plant efficiency as a function of output power for open and closed cycle MHD power plants. (WHK)
International Nuclear Information System (INIS)
Jeong, Wi S.; Kim, Tae W.; Suh, Kune Y.
2007-01-01
The supercritical gas turbine Brayton cycle has been adopted in the secondary loop of the Generation IV Nuclear Energy Systems, and planned to be installed in power conversion cycles of the nuclear fusion reactors as well. The supercritical carbon dioxide (SCO 2 ) is one of widely considered fluids for this concept. The potential beneficiaries include the Secure Transportable Autonomous Reactor- Liquid Metal (STAR-LM), the Korea Advanced Liquid Metal Reactor (KALIMER) and Battery Omnibus Reactor Integral System (BORIS) which is being developed at the Seoul National University. The reason for these welcomed applications is that the SCO 2 Brayton cycle can achieve higher overall energy conversion efficiency than the steam turbine Rankine cycle. Seoul National University has recently been working on the SCO 2 based Modular Optimized Brayton Integral System (MOBIS). The MOBIS design power conversion efficiency is about 45%. Gas turbine design is crucial part in achieving this high efficiency. In this paper, the preliminary analysis on first stage of gas turbine was performed using CFX as a solver
DEFF Research Database (Denmark)
Robotham, Antony John; Hertzum, Morten
2000-01-01
This paper will describe the multi-board concept, which is a working approach for supporting life cycle oriented design and product quality. Aspects of this concept include construction of a common working environment where multiple display boards depict scenarios of the product life cycle...... to believe that the multi-board concept promises to be a useful means of communication amongst the design team. We be-lieve that it fosters a thorough understanding of life cycle events, which, in turn, inspires the design of innovative products of the highest quality......., creating a shared quality mindset amongst design-ers, and developing creativity and synthesis in product design. The appropriateness of scenarios for supporting life cycle oriented design will be ar-gued and preliminary results from early experi-mentation will be presented.Initial results lead us...
Vapor cycle energy system for implantable circulatory assist devices. Final summary May--Oct 1976
International Nuclear Information System (INIS)
Watelet, R.P.; Ruggles, A.E.; Hagen, K.G.
1977-03-01
The report describes the development status of a heart assist system driven by a nuclear-fueled, electronically controlled vapor cycle engine termed the tidal regenerator engine (TRE). The TRE pressurization is controlled by a torque motor coupled to a displacer. The electrical power for the sensor, electronic logic and actuator is provided by thermoelectric modules interposed between the engine superheater and boiler. The TRE is direct-coupled to an assist blood pump which also acts as a blood-cooled heat exchanger, pressure-volume trasformer and sensor for the electronic logic. Engine cycle efficiency in excess of 14% has been demonstrated routinely. Overall system efficiency on 33 watts of over 9% has been demonstrated (implied 13% engine cycle efficiency). A binary version of this engine in the annular configuration is now being tested. The preliminary tests demonstrated 10% cycle efficiency on the first buildup which ran well and started easily
Sustainable Building Life Cycle Design
Directory of Open Access Journals (Sweden)
Ginzburg Alexander
2016-01-01
Full Text Available The current building life cycle management system in the Russian Federation is a family of discrete subsystems that exist independently for different building life cycle stages. In this situation building reliability and sustainable functioning are out of the question. The implementation of a united information model (BIM-model intended to describe building entire life cycle will allow to raise the sustainability, but this will happen only if goals and concerns of all participants of the project process are properly coordinated. An important figure of process sustainability is the organizational and technological reliability (OTR that describes the possibility of a system to reach a goal. In case of building life cycle design, the economical efficiency of a building can be considered as the goal. The required technical, ecological, organizational, and other parameters form a complex of constraints that determine the area of allowable values for building functioning. In its broad meaning, OTR may be understood as the probability of receiving an economical effect based on the value of organizational and economical reliability (OER.
Energy Technology Data Exchange (ETDEWEB)
Wang, Jinhua; Chen, Hao; Liu, Bing; Huang, Zuohua [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)
2008-09-15
Cycle-by-cycle variations of a spark ignition engine fueled with natural gas-hydrogen blends with hydrogen volumetric fraction of 0%, 12%, 23%, 30% and 40% were studied. The effect of hydrogen addition on cycle-by-cycle variations of the natural gas engine was analyzed. The results showed that the peak cylinder pressure, the maximum rate of pressure rise and the indicated mean effective pressure increased and their corresponding cycle-by-cycle variations decreased with the increase of hydrogen fraction at lean mixture operation. The interdependency between the combustion parameters and the corresponding crank angle tended to be strongly correlated with the increase of hydrogen fraction under lean mixture operation. Coefficient of variation of the indicated mean effective pressure gave a low level and is slightly influenced by hydrogen addition under the stoichiometric and relatively rich mixture operation while it decreased remarkably with the increase of hydrogen fraction under the lean mixture operation. The excessive air ratio at CoV{sub imep} = 10% extended to the leaner mixture side with the increase of hydrogen fraction and this indicated that the engine lean operating limit could be extended with hydrogen addition. (author)
Emissions-critical charge cooling using an organic rankine cycle
Ernst, Timothy C.; Nelson, Christopher R.
2014-07-15
The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.
Thermodynamic Analysis of an Irreversible Maisotsenko Reciprocating Brayton Cycle
Directory of Open Access Journals (Sweden)
Fuli Zhu
2018-03-01
Full Text Available An irreversible Maisotsenko reciprocating Brayton cycle (MRBC model is established using the finite time thermodynamic (FTT theory and taking the heat transfer loss (HTL, piston friction loss (PFL, and internal irreversible losses (IILs into consideration in this paper. A calculation flowchart of the power output (P and efficiency (η of the cycle is provided, and the effects of the mass flow rate (MFR of the injection of water to the cycle and some other design parameters on the performance of cycle are analyzed by detailed numerical examples. Furthermore, the superiority of irreversible MRBC is verified as the cycle and is compared with the traditional irreversible reciprocating Brayton cycle (RBC. The results can provide certain theoretical guiding significance for the optimal design of practical Maisotsenko reciprocating gas turbine plants.
The cell cycle-regulated genes of Schizosaccharomyces pombe.
Directory of Open Access Journals (Sweden)
Anna Oliva
2005-07-01
Full Text Available Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast. The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.
Preliminary study to improve the performance of SCWR-M during loss-of-flow accident
Energy Technology Data Exchange (ETDEWEB)
Liu, X.J., E-mail: xiaojingliu@sjtu.edu.cn [School of Nuclear Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China); Sun, C.; Wang, Z.D.; Chai, X.; Xiong, J.B.; Yang, Y.H. [School of Nuclear Science and Engineering, Shanghai Jiao Tong University, 800 Dong Chuan Road, Shanghai 200240 (China); Cheng, X. [Institute of Fusion and Nuclear Technology, Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, 76131 Karlsruhe (Germany)
2016-10-15
Highlights: • Validation of the ATHLET-SC code to the safety analysis for SCWR. • Loss of flow accident analysis for SCWR-M is performed. • The passive design parameter is optimized. • The optimized SCWR-M design shows a better safety performance. - Abstract: The SCWR-M is one of the conceptual core designs with mixed neutron spectrum (fast and thermal), which is developed at Shanghai Jiao Tong University. Some preliminary calculations of this new conceptual SCWR indicate the SCWR-M system gets better safety characteristics compared to other single spectrum supercritical water cooled reactors. Loss of flow accident (LOFA) is of particular importance among the abnormal events and accidents for SCWR-M. In order to perform the preliminary study to improve the current SCWR-M safety design, this paper presents the validation results of the ATHLET-SC code and optimization work for safety system design parameters of the ICS, ACC, GDCS based on LOFA analysis. The better performance of the optimized design parameters are demonstrated by comparison with the previous design.
Several remarks on the fuel cycle economy
International Nuclear Information System (INIS)
Roman Kubin; Rudolf Vespalec
2007-01-01
Present paper deals with some aspects influencing significantly cost of nuclear fuel and possibilities of its usage in optimal fuel cycle technology. Our discussion is focused on the phase of fuel procurement that means financial parts of the contract as well as its technical Appendices. Typically the fuel fabrication price is taken as the main economy indicator; nevertheless also many other financial and technical features of the contract must be taken into account in order to reach the best price of electricity sold into public energy grid. Our experience from several international tenders shows that the consistent complex of commercial and technical parameters of the contract is necessary to achieve optimal economic results and prepare proper conditions for advanced fuel cycle technology. Among those essential characteristics are payment conditions and schedule and extent of vendor's services and assistance to the operator. Very important role play also technical parameters, as safety and operational limits, influencing loading pattern quality and operating flexibility. Obviously also a level of operator's fuel cycle technology is a crucial point that is necessary for usage of technical quality of the fuel at the power plant. The final electricity price, produced by the plant, and uranium consumption are the only objective criteria to evaluate economic level of the fuel contract and the fuel cycle at all (Authors)
HEMISPHERIC HELICITY TREND FOR SOLAR CYCLE 24
International Nuclear Information System (INIS)
Hao Juan; Zhang Mei
2011-01-01
Using vector magnetograms obtained with the Spectro-polarimeter (SP) on board Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions that occurred in the descending phase of solar cycle 23 and the ascending phase of solar cycle 24. Our analysis gives the following results. (1) The 34 active regions of the solar cycle 24 follow the so-called hemispheric helicity rule, whereas the 30 active regions of the solar cycle 23 do not. (2) When combining all 64 active regions as one sample, they follow the hemispheric helicity sign rule as in most other observations. (3) Despite the so-far most accurate measurement of vector magnetic field given by SP/Hinode, the rule is still weak with large scatters. (4) The data show evidence of different helicity signs between strong and weak fields, confirming previous result from a large sample of ground-based observations. (5) With two example sunspots we show that the helicity parameters change sign from the inner umbra to the outer penumbra, where the sign of penumbra agrees with the sign of the active region as a whole. From these results, we speculate that both the Σ-effect (turbulent convection) and the dynamo have contributed in the generation of helicity, whereas in both cases turbulence in the convection zone has played a significant role.
De Angelis, S.; Rietbrock, A.; Lavallée, Y.; Lamb, O. D.; Lamur, A.; Kendrick, J. E.; Hornby, A. J.; von Aulock, F. W.; Chigna, G.
2016-12-01
Understanding the complex processes that drive volcanic unrest is crucial to effective risk mitigation. Characterization of these processes, and the mechanisms of volcanic eruptions, is only possible when high-resolution geophysical and geological observations are available over comparatively long periods of time. In November 2014, the Liverpool Earth Observatory, UK, in collaboration with the Instituto Nacional de Sismologia, Meteorologia e Hidrologia (INSIVUMEH), Guatemala, established a multi-parameter geophysical network at Santiaguito, one of the most active volcanoes in Guatemala. Activity at Santiaguito throughout the past decade, until the summer of 2015, was characterized by nearly continuous lava dome extrusion accompanied by frequent and regular small-to-moderate gas or gas-and-ash explosions. Over the past two years our network collected a wealth of seismic, acoustic and deformation data, complemented by campaign visual and thermal infrared measurements, and rock and ash samples. Here we present preliminary results from the analysis of this unique dataset. Using acoustic and thermal data collected during 2014-2015 we were able to assess volume fractions of ash and gas in the eruptive plumes. The small proportion of ash inferred in the plumes confirms estimates from previous, independent, studies, and suggests that these events did not involve significant magma fragmentation in the conduit. The results also agree with the suggestion that sacrificial fragmentation along fault zones in the conduit region, due to shear-induced thermal vesiculation, may be at the origin of such events. Finally, starting in the summer of 2015, our experiment captured the transition to a new phase of activity characterized by vigorous vulcanian-style explosions producing large, ash-rich, plumes and frequent hazardous pyroclastic flows, as well as the formation a large summit crater. We present evidence of this transition in the geophysical and geological data, and discuss its
Sun, Chengqi; Liu, Xiaolong; Hong, Youshi
2015-06-01
In this paper, ultrasonic (20 kHz) fatigue tests were performed on specimens of a high-strength steel in very high cycle fatigue (VHCF) regime. Experimental results showed that for most tested specimens failed in a VHCF regime, a fatigue crack originated from the interior of specimen with a fish-eye pattern, which contained a fine granular area (FGA) centered by an inclusion as the crack origin. Then, a two-parameter model is proposed to predict the fatigue life of high-strength steels with fish-eye mode failure in a VHCF regime, which takes into account the inclusion size and the FGA size. The model was verified by the data of present experiments and those in the literature. Furthermore, an analytic formula was obtained for estimating the equivalent crack growth rate within the FGA. The results also indicated that the stress intensity factor range at the front of the FGA varies within a small range, which is irrespective of stress amplitude and fatigue life.
International Nuclear Information System (INIS)
Kuan, W.
1995-01-01
Time-dependent inventories and flow rates for several components of the fuel cycle are modeled and studied through the use of a new modular-type model for the dynamic simulation of the fuel cycle in a fusion reactor. The complex dynamic behavior in the modeled subsystems is analyzed using this new model. Preliminary results using fuel cycle design configurations similar to ITER are presented and analyzed. The inventories and flow rates inside the primary vacuum pumping, fuel cleanup unit and isotope separation system are studied. Ways to minimize the tritium inventory are also assessed. This was performed by looking at various design options that could be used to minimize tritium inventory for specific components. (orig.)
International Nuclear Information System (INIS)
Habka, Muhsen; Ajib, Salman
2014-01-01
Highlights: • We analyzed performances of a series ORC–CHP plant versus the heating plant parameters. • ORC–CHP power is destructed when raising the heat demand or the return temperature. • Only the high supply temperatures of the heating plant affect negatively the performances. • Reducing the return temperature optimizes both the energetic and exergetic criteria. • Increasing the heat demand improves the exergetic efficiency of the total CHP system. - Abstract: The present work aims to analyze the performance characteristics of the series Combined Heat and Power (CHP) system based on Organic Rankine Cycle (ORC) under influence of the heating plant parameters without considering the chemistry of the geothermal water considered as heat source. For evaluation, energetic and exergetic criteria along with the heat transfer capacities have been determined, and also the working fluid R134a has been used. The results showed that increasing the heat demand or the return temperature and only the high supply temperatures lead to destruct the net power generated by the ORC–CHP system. While, influence of the last parameters on the total exergy efficiency and losses is different; whereas raising the heat demands optimizes these exergetic indicators, variation of the supply temperature leads to an optimum for these performances. Since increasing the return temperature has purely negative impacts on all exergetic and energetic criteria, the latter can be improved by reducing this temperature with attention to the heat transfer capacities. Thus, reduction of the return temperature about 5 °C lowers the exhausted stream losses by app. 25% and enhances the power generation by app. 52% and the total exergy efficiency by 9%
Sensitivity study on nitrogen Brayton cycle coupled with a small ultra-long cycle fast reactor
International Nuclear Information System (INIS)
Seo, Seok Bin; Seo, Han; Bang, In Cheol
2014-01-01
The main characteristics of UCFR are constant neutron flux and power density. They move their positions every moment at constant speed along with axial position of fuel rod for 60 years. Simultaneously with the development of the reactors, a new power conversion system has been considered. To solve existing issues of vigorous sodium-water reaction in SFR with steam power cycle, many researchers suggested a closed Brayton cycle as an alternative technique for SFR power conversion system. Many inactive gases are selected as a working fluid in Brayton power cycle, mainly supercritical CO 2 (S-CO 2 ). However, S-CO 2 still has potential for reaction with sodium. CO 2 -sodium reaction produces solid product, which has possibility to have an auto ignition reaction around 600 .deg. C. Thus, instead of S-CO 2 , CEA in France has developed nitrogen power cycle for ASTRID (Advanced Sodium Technological Reactor for Industrial Demonstration). In addition to inactive characteristic of nitrogen with sodium, its thermal and physical similarity with air enables to easily adopt to existing air Brayton cycle technology. In this study, for an optimized power conversion system for UCFR, a nitrogen Brayton cycle was analyzed in thermodynamic aspect. Based on subchannel analysis data of UCFR-100, a parametric study for thermal performance of nitrogen Brayton cycle was achieved. The system maximum pressure significantly affects to the overall efficiency of cycle, while other parameters show little effects. Little differences of the overall efficiencies for all cases between three stages (BOC, MOC, EOC) indicate that the power cycle of UCFR-100 maintains its performance during the operation
International Nuclear Information System (INIS)
Yu, Lina; Nakabayashi, Yuma; Saida, Kazuyoshi; Mochizuki, Masahito; Nishimoto, Kazutoshi; Kameyama, Masashi; Hirano, Shinro; Chigusa, Naoki
2011-01-01
A new Thermal Cycle Tempering Parameter (TCTP) to deal with the tempering effect during multi-pass thermal cycles has been proposed by extending Larson-Miller parameter (LMP). Experimental result revealed that the hardness in synthetic HAZ of the low alloy steel subjected to multi tempering thermal cycles has a good linear relationship with TCTP. By using this relationship, the hardness of the low-alloy steel reheated with tempering thermal cycles can be predicted when the original hardness is known. (author)
International Nuclear Information System (INIS)
Xie, Hui; Yang, Can
2013-01-01
Highlights: • Waste heat recovery behavior of the RCS during driving cycle was investigated. • Four operating modes were defined to describe the operating process of the RCS under driving cycle. • The operating mode switching is the crucial reason for on-road inefficiency. • The dry and isentropic fluids are superior to the wet ones on the adaptability to unsteady ExGE. • The effects of the vapor parameters on RCT-E and power mode percentage are opposite. - Abstract: The RCS (Rankine cycle system) used to recover the WHE (waste heat energy) from engines has been regarded as one of the most potential ways of achieving higher efficiency. However, it is of great challenge to keep the RCS still in good performance under driving cycle. This paper tries to reveal and explain its on-road inefficiency. The operating process of the RCS under driving cycle was analyzed in advance. Afterwards, four basic operating modes were defined, including startup mode, turbine turning mode, power mode and protection mode. Then, a RCS model was established and operating performances of the RCS under an actual driving cycle were discussed based on this model. The results indicate that the on-road RCS-E (Rankine cycle system efficiency) is as low as 3.63%, which is less than half of the design RCS-E (7.77%) at the rated operating point. Despite the inevitable vapor state fluctuation, it is the operating mode switching during the driving cycle that leads to the on-road inefficiency. Further investigations indicate that the expander safety temperature and its safety margin affected by the working fluids, designed superheat degree and evaporating pressure are the main factors determining the operating mode switching. Finally, the effects of the working fluids, designed superheat degree and evaporating pressure on the operating mode switching and RC (Rankine cycle) efficiencies were profoundly investigated. The study shows that the dry and isentropic fluids are superior to the wet
High-potential Working Fluids for Next Generation Binary Cycle Geothermal Power Plants
Energy Technology Data Exchange (ETDEWEB)
Zia, Jalal [GE Global Research; Sevincer, Edip; Chen, Huijuan; Hardy, Ajilli; Wickersham, Paul; Kalra, Chiranjeev; Laursen, Anna Lis; Vandeputte, Thomas
2013-06-29
A thermo-economic model has been built and validated for prediction of project economics of Enhanced Geothermal Projects. The thermo-economic model calculates and iteratively optimizes the LCOE (levelized cost of electricity) for a prospective EGS (Enhanced Geothermal) site. It takes into account the local subsurface temperature gradient, the cost of drilling and reservoir creation, stimulation and power plant configuration. It calculates and optimizes the power plant configuration vs. well depth. Thus outputs from the model include optimal well depth and power plant configuration for the lowest LCOE. The main focus of this final report was to experimentally validate the thermodynamic properties that formed the basis of the thermo-economic model built in Phase 2, and thus build confidence that the predictions of the model could be used reliably for process downselection and preliminary design at a given set of geothermal (and/or waste heat) boundary conditions. The fluid and cycle downselected was based on a new proprietary fluid from a vendor in a supercritical ORC cycle at a resource condition of 200°C inlet temperature. The team devised and executed a series of experiments to prove the suitability of the new fluid in realistic ORC cycle conditions. Furthermore, the team performed a preliminary design study for a MW-scale turbo expander that would be used for a supercritical ORC cycle with this new fluid. The following summarizes the main findings in the investigative campaign that was undertaken: 1. Chemical compatibility of the new fluid with common seal/gasket/Oring materials was found to be problematic. Neoprene, Viton, and silicone materials were found to be incompatible, suffering chemical decomposition, swelling and/or compression set issues. Of the materials tested, only TEFLON was found to be compatible under actual ORC temperature and pressure conditions. 2. Thermal stability of the new fluid at 200°C and 40 bar was found to be acceptable after 399
International Nuclear Information System (INIS)
Chan, Yi Herng; Yusup, Suzana; Quitain, Armando T.; Tan, Raymond R.; Sasaki, Mitsuru; Lam, Hon Loong; Uemura, Yoshimitsu
2015-01-01
Highlights: • Water is used as a clean solvent to liquefy palm biomass to bio-oil. • The optimum liquefaction condition of oil palm biomass is 390 °C and 25 MPa. • Optimum reaction time for liquefaction of empty fruit bunch and palm mesocarp fiber is 120 min. • Optimum reaction time for liquefaction of palm kernel shell is 240 min. • From the life cycle assessment, a net 2.29 kg CO 2 equivalent is generated per kg of bio-oil produced. - Abstract: This paper presents the studies on the effect of three process parameters; temperature, pressure and reaction time on the subcritical and supercritical hydrothermal liquefaction of oil palm empty fruit bunch, palm mesocarp fiber and palm kernel shell. The effect of temperature (330–390 °C), pressure (25–35 MPa) and reaction time (30–240 min) on bio-oil yields were investigated using a Inconel batch reactor. The optimum liquefaction condition for empty fruit bunch, palm mesocarp fiber and palm kernel shell was at supercritical condition of water; 390 °C and 25 MPa. For the effect of reaction time, bio-oil from empty fruit bunch and palm mesocarp fiber attained maximum yields at 120 min, whereas bio-oil yield from palm kernel shell continued to increase at reaction time of 240 min. Lastly, a life cycle assessment based on a conceptual biomass hydrothermal liquefaction process for bio-oil production was constructed and presented
Study of characteristics of Th-U cycle in CANDU SCWR
International Nuclear Information System (INIS)
Shi, J.; Shi, G.
2010-01-01
The flexibility of CANDU technology allows the use of different fuel cycles including various uranium-driven thorium cycles. Direct self-recycle method and heterogeneous cycle modes with supercritical water as coolant were studied for (U,Th)O 2 CANFLEX fuel bundle. Lattice pitch and enrichment of driver fuel were treated as independent variables, taking account of coolant void reactivity, fuel burnup, and linear power uneven factor. In the end, appropriate cycle mode and parameters of bundle were chosen for (U,Th)O 2 cycle in CANDU SCWR. Calculations were processed by the two-dimensional multigroup neutron transport code WIMS-AECL release 3.1.2.1. (author)
Cycle analysis of MCFC/gas turbine system
Directory of Open Access Journals (Sweden)
Musa Abdullatif
2017-01-01
Full Text Available High temperature fuel cells such as the solid oxide fuel cell (SOFC and the molten carbonate fuel cell (MCFC are considered extremely suitable for electrical power plant application. The molten carbonate fuel cell (MCFC performances is evaluated using validated model for the internally reformed (IR fuel cell. This model is integrated in Aspen Plus™. Therefore, several MCFC/Gas Turbine systems are introduced and investigated. One of this a new cycle is called a heat recovery (HR cycle. In the HR cycle, a regenerator is used to preheat water by outlet air compressor. So the waste heat of the outlet air compressor and the exhaust gases of turbine are recovered and used to produce steam. This steam is injected in the gas turbine, resulting in a high specific power and a high thermal efficiency. The cycles are simulated in order to evaluate and compare their performances. Moreover, the effects of an important parameters such as the ambient air temperature on the cycle performance are evaluated. The simulation results show that the HR cycle has high efficiency.
Cycle analysis of MCFC/gas turbine system
Musa, Abdullatif; Alaktiwi, Abdulsalam; Talbi, Mosbah
2017-11-01
High temperature fuel cells such as the solid oxide fuel cell (SOFC) and the molten carbonate fuel cell (MCFC) are considered extremely suitable for electrical power plant application. The molten carbonate fuel cell (MCFC) performances is evaluated using validated model for the internally reformed (IR) fuel cell. This model is integrated in Aspen Plus™. Therefore, several MCFC/Gas Turbine systems are introduced and investigated. One of this a new cycle is called a heat recovery (HR) cycle. In the HR cycle, a regenerator is used to preheat water by outlet air compressor. So the waste heat of the outlet air compressor and the exhaust gases of turbine are recovered and used to produce steam. This steam is injected in the gas turbine, resulting in a high specific power and a high thermal efficiency. The cycles are simulated in order to evaluate and compare their performances. Moreover, the effects of an important parameters such as the ambient air temperature on the cycle performance are evaluated. The simulation results show that the HR cycle has high efficiency.
Directory of Open Access Journals (Sweden)
Carolina L. Haass-Koffler
2017-12-01
Full Text Available The data in this article outline the methods used for the administration of GET 73 in the first time-in-human manuscript entitled âPhase I randomized clinical trial for the safety, tolerability and preliminary pharmacokinetics of the mGluR5 negative allosteric modulator GET 73 following single and repeated doses in healthy male volunteersâ (Haass-Koffler et al., 2017 [1]. Data sets are provided in two different manners. The first series of tables provided includes procedural information about the experiments conducted. The next series of tables provided includes Pharmacokinetic (PK parameters for GET 73 and its main metabolite MET 2. This set of data is comprised by two experiments: Experiment 1 references a single ascending dose administration of GET 73 and Experiment 2 references a repeated ascending dose administration of GET 73. Keywords: Glutamate receptor subtype 5 (mGlu5, Allosteric modulator, GET 73, Safety, Tolerability
International Nuclear Information System (INIS)
Epiney, A.; Mikityuk, K.; Chawla, R.; Alpy, N.; Haubensack, D.; Malo, J.Y.
2009-01-01
This paper reports a preliminary design study of a Brayton cycle which would be a dedicated, standalone Decay Heat Removal (DHR) loop of the Gas-cooled Fast Reactor (GFR). In comparison to the DHR reference strategy developed during the GFR pre-conceptual design phase (which was completed by the CEA at the end of 2007), the salient feature of this alternative device would be to combine the energetic autonomy of the natural convection process - which is foreseen for operation at high and medium pressures - to the efficiency of the forced convection process which is foreseen for operation down to very low pressures. An analytical model, the so-called 'Brayton scoping' model, is described in the paper. This is based on simplified thermodynamical and aerodynamical equations and was developed to highlight design choices. First simulations of the proposed device's performance during loss-of-coolant-accident (LOCA) transients have been performed using the CATHARE code, and these are also reported. Analysis of the simulation results are consistent with the first insights obtained from usage of the 'Brayton scoping' model, e.g. the turbomachine accelerates during the depressurization process to tend towards a steady rotational speed value which is inversely proportional to the pressure. For small break LOCA events, the device operates successfully as regards its safety function and delivers to the core a relatively unperturbed cooling mass flowrate as a function of pressure change. However, further studies are required for medium to large break sizes, since certain stability concerns have been met in such cases. For example, an unexpected turbomachine stoppage was induced during the transients, resulting in loss of the necessary core cooling mass flow. (author)
The thorium fuel cycle in water-moderated reactor systems
International Nuclear Information System (INIS)
Critoph, E.
1977-05-01
Thorium and uranium cycles are compared with regard to reactor characteristics and technology, fuel-cycle technology, economic parameters, fuel-cycle costs, and system characteristics. In heavy-water reactors (HWRs) thorium cycles having uranium requirements at equilibrium ranging from zero to a quarter of those for the natural-uranium once-through cycle appear feasible. An 'inventory' of uranium of between 1 and 2 Mg/MW(e) is required for the transition to equilibrium. The cycles with the lowest uranium requirements compete with the others only at high uranium prices. Using thorium in light-water reactors, uranium requirements can be reduced by a factor of between two and three from the once-through uranium cycle. The light-water breeder reactor, promising zero uranium requirements at equilibrium, is being developed. Larger uranium inventories are required than for the HWRs. The lead time, from a decision to use thorium to significant impact on uranium utilization (compared to uranium cycle, recycling plutonium) is some two decades
Preliminary assessment of a symbiotic fusion--fission power system using the TH/U refresh fuel cycle
International Nuclear Information System (INIS)
Bender, D.J.; Lee, J.D.; Moir, R.W.
1977-10-01
Studies of the mirror hybrid reactor by LLL/GA have concluded that the most promising role for this reactor concept is that of a producer of fissile fuel for fission reactors. Studies to date have examined primarily the U/Pu fuel cycle with light-water reactors serving as the consumers of the hybrid-bred fissile fuel; the specific scenarios examined required reprocessing and refabrication of the bred fuel before introduction into the fission reactor. This combination of technologies was chosen to illustrate the manner in which the hybrid reactor concept could serve the needs of, and use the technology of, the fission reactor industry as it now exists (and as it was thought it would evolve). However, the current U.S. Administration has expressed strong concerns about proliferation of nuclear weapons capability and terrorist diversion of weapons-grade nuclear materials. These concerns are based on the projected technology for the light-water reactor/fast breeder reactor using the U/Pu fuel cycle and extensive reprocessing/refabrication. A symbiotic nuclear power generation concept (hybrid fissile producer plus fission burner reactors) is described which eliminates those aspects of the present nuclear fuel cycle that (may) represent significant proliferation/diversion risks. Specifically, the proposed concept incorporates the following features: (1)Th/U 233 fuel cycle, (2) no reprocessing or fabrication of fissile material, and (3) no fissile material in a weapons-grade state
On the Reduced Geoeffectiveness of Solar Cycle 24: A Moderate Storm Perspective
Selvakumaran, R.; Veenadhari, B.; Akiyama, S.; Pandya, Megha; Gopalswamy, N,; Yashiro, S.; Kumar, Sandeep; Makela, P.; Xie, H.
2016-01-01
The moderate and intense geomagnetic storms are identified for the first 77 months of solar cycles 23 and 24. The solar sources responsible for the moderate geomagnetic storms are indentified during the same epoch for both the cycles. Solar cycle 24 has shown nearly 80% reduction in the occurrence of intense storms whereas it is only 40% in case of moderate storms when compared to previous cycle. The solar and interplanetary characteristics of the moderate storms driven by coronal mass ejection (CME) are compared for solar cycles 23 and 24 in order to see reduction in geoeffectiveness has anything to do with the occurrence of moderate storm. Though there is reduction in the occurrence of moderate storms, the Dst distribution does not show much difference. Similarly, the solar source parameters like CME speed, mass, and width did not show any significant variation in the average values as well as the distribution. The correlation between VBz and Dst is determined, and it is found to be moderate with value of 0.68 for cycle 23 and 0.61 for cycle 24. The magnetospheric energy flux parameter epsilon (epsilon) is estimated during the main phase of all moderate storms during solar cycles 23 and 24. The energy transfer decreased in solar cycle 24 when compared to cycle 23. These results are significantly different when all geomagnetic storms are taken into consideration for both the solar cycles.
Pasch, James Jay
2017-02-07
A method of resolving a balanced condition that generates control parameters for start-up and steady state operating points and various component and cycle performances for a closed split flow recompression cycle system. The method provides for improved control of a Brayton cycle thermal to electrical power conversion system. The method may also be used for system design, operational simulation and/or parameter prediction.
Absorption heat cycles. An experimental and theoretical study
International Nuclear Information System (INIS)
Abrahamsson, K.
1993-09-01
A flow sheeting programme, SHPUMP, was developed for simulating different absorption heat cycles. The programme consists of ten different modules which allow the user to construct his own absorption cycle. The ten modules configurate evaporators, absorbers, generators, rectifiers, condensers, solution heat exchangers, pumps, valves, mixers and splitters. Seven basic and well established absorption cycles are available in the configuration data base of the programme. A new Carnot model is proposed heat cycles. Together with exergy analysis, general equations for the Carnot coefficient of performance and equations for thermodynamic efficiency, exergetic efficiency and exergy index, are derived, discussed and compared for both absorption heat pumps and absorption heat transformers. Utilizing SHPUMP, simulation results are presented for different configurations where absorption heat cycles are suggested to be incorporated in three different unit operations within both pulp and paper and oleochemical industries. One of the application studies reveled that an absorption heat transformer incorporated with an evaporation plant in a major pulp and paper industry, would save 18% of the total prime energy consumption in one of the evaporation plants. It was also concluded that installing an absorption heat pump in a paper drying plant would result in steam savings equivalent to 12 MW. An experimental absorption heat transformer unit operating with self-circulation has been modified and thoroughly tested. A reference heat transformer plant has been designed and installed in a major pulp and paper mill where it is directly incorporated with one of the evaporation plants. Preliminary plant operation data are presented. 72 refs, 63 figs, 33 tabs
International Nuclear Information System (INIS)
Neiers, F.; Madhurantakam, C.; Fälker, S.; Normark, S.; Henriques-Normark, B.; Achour, A.
2008-01-01
Crystallization conditions and preliminary X-ray diffraction analysis of the S. pneumoniae-derived pilus-associated protein sortase C are reported. The pilus-associated sortase C from Streptococcus pneumoniae (SrtC or Srt-2) acts as a polymerase for the pilus subunit proteins RrgA and RrgB. Here, the crystallization and preliminary X-ray diffraction analysis of three crystal forms of SrtC are reported. One crystal form belongs to space group P2 1 2 1 2 1 , with unit-cell parameters a = 48.9, b = 96.9, c = 98.9 Å, α = β = γ = 90°. The other two crystal forms belong to space group P222, with unit-cell parameters a = 48.8, b = 97.2, c = 99.2 Å, α = β = γ = 90° and a = 48.6, b = 96.5, c = 98.8 Å, α = β = γ = 90°, respectively. Preliminary analysis indicates the presence of two molecules in the asymmetric unit of the crystal for all three forms
International Nuclear Information System (INIS)
Granovskii, M.; Dincer, I.; Rosen, M. A.; Pioro, I
2007-01-01
The power generation efficiency of nuclear plants is mainly determined by the permissible temperatures and pressures of the nuclear reactor fuel and coolants. These parameters are limited by materials properties and corrosion rates and their effect on nuclear reactor safety. The advanced materials for the next generation of CANDU reactors, which employ steam as a coolant and heat carrier, permit the increased steam parameters (outlet temperature up to 625 degree C and pressure of about 25 MPa). Supercritical water-cooled (SCW) nuclear power plants are expected to increase the power generation efficiency from 35 to 45%. Supercritical water-cooled nuclear reactors can be linked to thermochemical water splitting cycles for hydrogen production. An increased steam temperature from the nuclear reactor makes it also possible to utilize its energy in thermochemical water splitting cycles. These cycles are considered by many as one of the most efficient ways to produce hydrogen from water and to have advantages over traditional low-temperature water electrolysis. However, even lower temperature water splitting cycles (Cu-Cl, UT-3, etc.) require a heat supply at the temperatures over 550-600 degree C. A sufficient increase in the heat transfer from the nuclear reactor to a thermochemical water splitting cycle, without jeopardizing nuclear reactor safety, might be effectively achieved by application of a heat pump which increases the temperature the heat supplied by virtue of a cyclic process driven by mechanical or electrical work. A high temperature chemical heat pump which employs the reversible catalytic methane conversion reaction is proposed. The reaction shift from exothermic to endothermic and back is achieved by a change of the steam concentration in the reaction mixture. This heat pump, coupled with a SCW nuclear plant on one side and thermochemical water splitting cycle on the other, increases the temperature level of the 'nuclear' heat and, thus, the intensity of
Tuning the operational parameters of the first microtron stage
International Nuclear Information System (INIS)
Jahnke, Cristiane; Silva, Tiago F.; Martins, Marcos N.
2013-01-01
The Laboratório do Acelerador Linear is building a racetrack microtron electron accelerator. It has two acceleration stages: the booster and the main microtron. The aim of this work is to optimize the operation parameters of the booster stage by means of simulation tools. The accelerator admittances were determined successfuly and the results are presented. The injection beam has been characterized previously, and the available data were used to match the transverse beam emittances of the injector to the transverse beam admittances of the booster. Preliminary results showed that the simulations have a good agreement with the working parameters.
A Comparison of Single-Cycle Versus Multiple-Cycle Proof Testing Strategies
McClung, R. C.; Chell, G. G.; Millwater, H. R.; Russell, D. A.; Millwater, H. R.
1999-01-01
Single-cycle and multiple-cycle proof testing (SCPT and MCPT) strategies for reusable aerospace propulsion system components are critically evaluated and compared from a rigorous elastic-plastic fracture mechanics perspective. Earlier MCPT studies are briefly reviewed. New J-integral estimation methods for semielliptical surface cracks and cracks at notches are derived and validated. Engineering methods are developed to characterize crack growth rates during elastic-plastic fatigue crack growth (FCG) and the tear-fatigue interaction near instability. Surface crack growth experiments are conducted with Inconel 718 to characterize tearing resistance, FCG under small-scale yielding and elastic-plastic conditions, and crack growth during simulated MCPT. Fractography and acoustic emission studies provide additional insight. The relative merits of SCPT and MCPT are directly compared using a probabilistic analysis linked with an elastic-plastic crack growth computer code. The conditional probability of failure in service is computed for a population of components that have survived a previous proof test, based on an assumed distribution of initial crack depths. Parameter studies investigate the influence of proof factor, tearing resistance, crack shape, initial crack depth distribution, and notches on the MCPT versus SCPT comparison. The parameter studies provide a rational basis to formulate conclusions about the relative advantages and disadvantages of SCPT and MCPT. Practical engineering guidelines are proposed to help select the optimum proof test protocol in a given application.
Directory of Open Access Journals (Sweden)
Weilian Qu
2017-01-01
Full Text Available The low-cycle fatigue experiments of mild carbon Q235B steel and its related welded-metal specimens are performed under uniaxial, in-phase, and 90° out-of-phase loading conditions. Significant additional cyclic hardening for 90° out-of-phase loading conditions is observed for both base metal and its related weldment. Besides, welding process produces extra additional hardening under the same loading conditions compared with the base metal. Multiaxial low-cycle fatigue strength under 90° out-of-phase loading conditions is significantly reduced for both base-metal and welded-metal specimens. The weldment has lower fatigue life than the base metal under the given loading conditions, and the fatigue life reduction of weldment increases with the increasing strain amplitude. The KBM, FS, and MKBM critical plane parameters are evaluated for the fatigue data obtained. The FS and MKBM parameters are found to show better correlation with fatigue lives for both base-metal and welded-metal specimens.
Le , Van Long
2014-01-01
This thesis concerns the feasibility study of subcritical and supercritical organic Rankine cycles for industrial waste heat recovery at relatively low temperature. Initially, a state of the art of ORCs (Organic Rankine Cycles) and their working fluids has been achieved. We conducted a preliminary comparison of several configurations from the scientific literature. In a second step, methods of energy and exergy analysis were applied to evaluate and optimize the performance of the ORCs. Indeed...
Le , Van Long
2014-01-01
This thesis concerns the feasibility study of subcritical and supercritical organic Rankine cycles for industrial waste heat recovery at relatively low temperature.Initially, a state of the art of ORCs (Organic Rankine Cycles) and their working fluids has been achieved. We conducted a preliminary comparison of several configurations from the scientific literature.In a second step, methods of energy and exergy analysis were applied to evaluate and optimize the performance of the ORCs. Indeed, ...
Potential efficiencies of open- and closed-cycle CO, supersonic, electric-discharge lasers
Monson, D. J.
1976-01-01
Computed open- and closed-cycle system efficiencies (laser power output divided by electrical power input) are presented for a CW carbon monoxide, supersonic, electric-discharge laser. Closed-system results include the compressor power required to overcome stagnation pressure losses due to supersonic heat addition and a supersonic diffuser. The paper shows the effect on the system efficiencies of varying several important parameters. These parameters include: gas mixture, gas temperature, gas total temperature, gas density, total discharge energy loading, discharge efficiency, saturated gain coefficient, optical cavity size and location with respect to the discharge, and supersonic diffuser efficiency. Maximum open-cycle efficiency of 80-90% is predicted; the best closed-cycle result is 60-70%.
Fatigue crack propagation under elastic plastic medium at elevated temperature
International Nuclear Information System (INIS)
Asada, Y.; Yuuki, R.; Sakon, T.; Sunamoto, D.; Tokimasa, K.; Makino, Y.; Kitagawa, M; Shingai, K.
1980-01-01
The purposes of the present study are to establish the testing method to obtain compatible data on the low cycle fatigue crack propagation at elevated temperature, and to investigate the parameter controlling the crack propagation rate. In the present study, the preliminary experiments have been carried out on low cycle fatigue crack propagation behaviour in type 304 stainless steel in air at 550 0 C, using two types of specimen with a through thickness notch. Both strain controlled and stress controlled fatigue tests have been done under a fully reversed strain or stress cycling. The data obtained are correlated with some fracture mechanics parameters and are discussed with the appropriate parameter for evaluating the low cycle fatigue crack propagation behaviour at elevated temperature. (author)
International Nuclear Information System (INIS)
Hagen, M.
1977-01-01
The concept of co-locating and integrating fuel cycle facilities at one site is discussed. This concept offers considerable advantages, especially in minimizing the amount of radioactive material to be transported on public roads. Safeguards and physical protection as relating to such an integrated system of facilities are analysed in detail, also industrial and commercial questions. An overall risk-benefit evaluation turns out to be in favour of fuel cycle centres. These centres seem to be specifically attractive with regard to the back end of the fuel cycle, including on-site disposal of radioactive wastes. The respective German approach is presented as an example. Special emphasis is given to the site selection procedures in this case. Time scale and cost for the implementation of this concept are important factors to be looked at. Since participation of governmental institutions in these centres seems to be indispensable their respective roles as compared to industry must be clearly defined. The idea of adjusting fuel cycle centres to regional rather than national use might be an attractive option, depending on the specific parameters in the region, though results of existing multinational ventures are inconclusive in this respect. Major difficulties might be expected e.g. because of different national safety regulations and standards as well as commercial conditions among partner countries. Public acceptance in the host country seems to be another stumbling block for the realization of this type of multinational facilities
Influence of safety limitations on the fuel cycle management
Energy Technology Data Exchange (ETDEWEB)
Mancini, G
1972-05-03
The choice of an optimum fuel cycle has been up to now governed from the safety point of view, by the setting of very general limitations on few parameters, as for instance on the fuel temperature and on the surface temperature. As a better understanding of the design and materials limitations become available, the philosophy of the fuel cycle optimisation can be improved. The aim of this contribution is to shortly revise the safety aspects involved in the choice of a fuel cycle management and thereafter try to draw some general conclusions.
Second Law Of Thermodynamics Analysis Of Triple Cycle Power Plant
Directory of Open Access Journals (Sweden)
Matheus M. Dwinanto
2012-11-01
Full Text Available Triple cycle power plant with methane as a fuel has been analyzed on the basis of second law of thermodynamics.In this model, ideal Brayton cycle is selected as a topping cycle as it gives higher efficiency at lower pressure ratio comparedintercooler and reheat cycle. In trilple cycle the bottoming cycles are steam Rankine and organic Rankine cycle. Ammoniahas suitable working properties like critical temperature, boiling temperature, etc. Steam cycle consists of a deaerator andreheater. The bottoming ammonia cycle is a ideal Rankine cycle. Single pressure heat recovery steam and ammoniagenerators are selected for simplification of the analysis. The effects of pressure ratio and maximum temperature which aretaken as important parameters regarding the triple cycle are discussed on performance and exergetic losses. On the otherhand, the efficiency of the triple cycle can be raised, especially in the application of recovering low enthalpy content wasteheat. Therefore, by properly combining with a steam Rankine cycle, the ammonia Rankine cycle is expected to efficientlyutilize residual yet available energy to an optimal extent. The arrangement of multiple cycles is compared with combinedcycle having the same sink conditions. The parallel type of arrangement of bottoming cycle is selected due to increasedperformance.
Hierarchical modeling and robust synthesis for the preliminary design of large scale complex systems
Koch, Patrick Nathan
Large-scale complex systems are characterized by multiple interacting subsystems and the analysis of multiple disciplines. The design and development of such systems inevitably requires the resolution of multiple conflicting objectives. The size of complex systems, however, prohibits the development of comprehensive system models, and thus these systems must be partitioned into their constituent parts. Because simultaneous solution of individual subsystem models is often not manageable iteration is inevitable and often excessive. In this dissertation these issues are addressed through the development of a method for hierarchical robust preliminary design exploration to facilitate concurrent system and subsystem design exploration, for the concurrent generation of robust system and subsystem specifications for the preliminary design of multi-level, multi-objective, large-scale complex systems. This method is developed through the integration and expansion of current design techniques: (1) Hierarchical partitioning and modeling techniques for partitioning large-scale complex systems into more tractable parts, and allowing integration of subproblems for system synthesis, (2) Statistical experimentation and approximation techniques for increasing both the efficiency and the comprehensiveness of preliminary design exploration, and (3) Noise modeling techniques for implementing robust preliminary design when approximate models are employed. The method developed and associated approaches are illustrated through their application to the preliminary design of a commercial turbofan turbine propulsion system; the turbofan system-level problem is partitioned into engine cycle and configuration design and a compressor module is integrated for more detailed subsystem-level design exploration, improving system evaluation.
International Nuclear Information System (INIS)
Anantatmula, R.P.
1984-01-01
A preliminary sensitivity analysis was performed for the corrosion models developed for Basalt Waste Isolation Project container materials. The models describe corrosion behavior of the candidate container materials (low carbon steel and Fe9Cr1Mo), in various environments that are expected in the vicinity of the waste package, by separate equations. The present sensitivity analysis yields an uncertainty in total uniform corrosion on the basis of assumed uncertainties in the parameters comprising the corrosion equations. Based on the sample scenario and the preliminary corrosion models, the uncertainty in total uniform corrosion of low carbon steel and Fe9Cr1Mo for the 1000 yr containment period are 20% and 15%, respectively. For containment periods ≥ 1000 yr, the uncertainty in corrosion during the post-closure aqueous periods controls the uncertainty in total uniform corrosion for both low carbon steel and Fe9Cr1Mo. The key parameters controlling the corrosion behavior of candidate container materials are temperature, radiation, groundwater species, etc. Tests are planned in the Basalt Waste Isolation Project containment materials test program to determine in detail the sensitivity of corrosion to these parameters. We also plan to expand the sensitivity analysis to include sensitivity coefficients and other parameters in future studies. 6 refs., 3 figs., 9 tabs
Dynamics of the cell-cycle network under genome-rewiring perturbations
International Nuclear Information System (INIS)
Katzir, Yair; Elhanati, Yuval; Braun, Erez; Averbukh, Inna
2013-01-01
The cell-cycle progression is regulated by a specific network enabling its ordered dynamics. Recent experiments supported by computational models have shown that a core of genes ensures this robust cycle dynamics. However, much less is known about the direct interaction of the cell-cycle regulators with genes outside of the cell-cycle network, in particular those of the metabolic system. Following our recent experimental work, we present here a model focusing on the dynamics of the cell-cycle core network under rewiring perturbations. Rewiring is achieved by placing an essential metabolic gene exclusively under the regulation of a cell-cycle's promoter, forcing the cell-cycle network to function under a multitasking challenging condition; operating in parallel the cell-cycle progression and a metabolic essential gene. Our model relies on simple rate equations that capture the dynamics of the relevant protein–DNA and protein–protein interactions, while making a clear distinction between these two different types of processes. In particular, we treat the cell-cycle transcription factors as limited ‘resources’ and focus on the redistribution of resources in the network during its dynamics. This elucidates the sensitivity of its various nodes to rewiring interactions. The basic model produces the correct cycle dynamics for a wide range of parameters. The simplicity of the model enables us to study the interface between the cell-cycle regulation and other cellular processes. Rewiring a promoter of the network to regulate a foreign gene, forces a multitasking regulatory load. The higher the load on the promoter, the longer is the cell-cycle period. Moreover, in agreement with our experimental results, the model shows that different nodes of the network exhibit variable susceptibilities to the rewiring perturbations. Our model suggests that the topology of the cell-cycle core network ensures its plasticity and flexible interface with other cellular processes
Spectral analysis and markov switching model of Indonesia business cycle
Fajar, Muhammad; Darwis, Sutawanir; Darmawan, Gumgum
2017-03-01
This study aims to investigate the Indonesia business cycle encompassing the determination of smoothing parameter (λ) on Hodrick-Prescott filter. Subsequently, the components of the filter output cycles were analyzed using a spectral method useful to know its characteristics, and Markov switching regime modeling is made to forecast the probability recession and expansion regimes. The data used in the study is real GDP (1983Q1 - 2016Q2). The results of the study are: a) Hodrick-Prescott filter on real GDP of Indonesia to be optimal when the value of the smoothing parameter is 988.474, b) Indonesia business cycle has amplitude varies between±0.0071 to±0.01024, and the duration is between 4 to 22 quarters, c) the business cycle can be modelled by MSIV-AR (2) but regime periodization is generated this model not perfect exactly with real regime periodzation, and d) Based on the model MSIV-AR (2) obtained long-term probabilities in the expansion regime: 0.4858 and in the recession regime: 0.5142.
Size of the coming solar cycle 24 based on Ohl's Precursor Method, final estimate
Directory of Open Access Journals (Sweden)
R. P. Kane
2010-07-01
Full Text Available In Ohl's Precursor Method (Ohl, 1966, 1976, the geomagnetic activity during the declining phase of a sunspot cycle is shown to be well correlated with the size (maximum sunspot number Rz(max of the next cycle. For solar cycle 24, Kane (2007a used aa(min=15.5 (12-month running mean, which occurred during March–May of 2006 and made a preliminary estimate Rz(max=124±26 (12-month running mean. However, in the next few months, the aa index first increased and then decreased to a new low value of 14.8 in July 2007. With this new low value, the prediction was Rz(max=117±26 (12-month running mean. However, even this proved a false signal. Since then, the aa values have decreased considerably and the last 12-monthly value is 8.7, centered at May 2009. For solar cycle 24, using aa(min=8.7, the latest prediction is, Rz(max=58.0±25.0.
Parameters affecting the life cycle performance of PV technologies and systems
International Nuclear Information System (INIS)
Pacca, Sergio; Sivaraman, Deepak; Keoleian, Gregory A.
2007-01-01
This paper assesses modeling parameters that affect the environmental performance of two state-of-the-art photovoltaic (PV) electricity generation technologies: the PVL136 thin film laminates and the KC120 multi-crystalline modules. We selected three metrics to assess the modules' environmental performance, which are part of an actual 33 kW installation in Ann Arbor, MI. The net energy ratio (NER), the energy pay back time (E-PBT), and the CO 2 emissions are calculated using process based LCA methods. The results reveal some of the parameters, such as the level of solar radiation, the position of the modules, the modules' manufacturing energy intensity and its corresponding fuel mix, and the solar radiation conversion efficiency of the modules, which affect the final analytical results. A sensitivity analysis shows the effect of selected parameters on the final results. For the baseline scenario, the E-PBT for the PVL136 and KC120 are 3.2 and 7.5 years, respectively. When expected future conversion efficiencies are tested, the E-PBT is 1.6 and 5.7 years for the PVL136 and the KC120, respectively. Based on the US fuel mix, the CO 2 emissions for the PVL136 and the KC120 are 34.3 and 72.4 g of CO 2 /kW h, respectively. The most effective way to improve the modules' environmental performance is to reduce the energy input in the manufacturing phase of the modules, provided that other parameters remain constant. Consequently, the use of PV as an electricity source during PV manufacturing is also assessed. The NER of the supplier PV is key for the performance of this scheme. The results show that the NER based on a PV system can be 3.7 times higher than the NER based on electricity supplied by the traditional grid mix, and the CO 2 emissions can be reduced by 80%
Transition Towards a Sustainable Nuclear Fuel Cycle
International Nuclear Information System (INIS)
McCarthy, K.; Romanello, V.; Schwenk-Ferrero, A.; Vezzoni, B.; Gabrielli, F.; Maschek, W.; Rineiski, A.; Salvatores, M.
2013-01-01
. In this respect, it is considered that the potential future scarcity of uranium resources is not at all unreasonable, but it is a very serious perspective for the regions of the world where the energy demand growth is and will very probably continue to be significant with the use of nuclear energy to meet at least partially that demand. In fact, despite the seriousness of the recent Fukushima Daiichi accident, only a few countries (essentially in the OECD region) have reacted with an abrupt decision to phase out nuclear power. Most countries, where the energy demand growth corresponds to an urgent need to achieve widely improved living standards, have launched or completed extensive reviews of their nuclear programmes, but are also continuing with ongoing construction projects. The results of this study are very much related to the hypotheses made, in particular in terms of energy demand growth. However, some general trends seem to be of a general value and can motivate further studies. It was confirmed in this investigation that a rapid development of fast reactors, especially in areas with expanding economies and strong energy demand growth, is essential for nuclear energy sustainability, for saving natural uranium resources worldwide and for reducing high-level waste generation requiring disposal. A key parameter is the fast reactor doubling time which has to be chosen appropriately in order to meet energy requirements. In the case of an open cycle, a potential increase in pressure on the uranium market could be expected towards the end of the current century. Moreover, the increase in mining needs of unequally distributed resources can be a factor of uncertainty with an impact potentially even more important of uranium cost considerations. It would, however, be a very significant challenge to develop suitable fuel cycle infrastructure especially in the world regions that presently have a limited number of (or no) nuclear power plants. In fact, the needed fuel
The CNO Bi-cycle in the Open Cluster NGC 752
Hawkins, Keith; Schuler, S.; King, J.; The, L.
2011-01-01
The CNO bi-cycle is the primary energy source for main sequence stars more massive than the sun. To test our understanding of stellar evolution models using the CNO bi-cycle, we have undertaken light-element (CNO) abundance analysis of three main sequence dwarf stars and three red giant stars in the open cluster NGC 752 utilizing high resolution (R 50,000) spectroscopy from the Keck Observatory. Preliminary results indicate, as expected, there is a depletion of carbon in the giants relative to the dwarfs. Additional analysis is needed to determine if the amount of depletion is in line with model predictions, as seen in the Hyades open cluster. Oxygen abundances are derived from the high-excitation O I triplet, and there is a 0.19 dex offset in the [O/H] abundances between the giants and dwarfs which may be explained by non-local thermodynamic equilibrium (NLTE), although further analysis is needed to verify this. The standard procedure for spectroscopically determining stellar parameters used here allows for a measurement of the cluster metallicity, [Fe/H] = 0.04 ± 0.02. In addition to the Fe abundances we have determined Na, Mg, and Al abundances to determine the status of other nucleosynthesis processes. The Na, Mg and Al abundances of the giants are enhanced relative to the dwarfs, which is consistent with similar findings in giants of other open clusters. Support for K. Hawkins was provided by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 13 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.
Zhang, Jianqiang; Wang, Zhenguo; Li, Qinglian
2017-09-01
The efficiency calculation and cycle optimization were carried out for the Synergistic Air-Breathing Rocket Engine (SABRE) with deeply precooled combined cycle. A component-level model was developed for the engine, and exergy efficiency analysis based on the model was carried out. The methods to improve cycle efficiency have been proposed. The results indicate cycle efficiency of SABRE is between 29.7% and 41.7% along the flight trajectory, and most of the wasted exergy is occupied by the unburned hydrogen in exit gas. Exergy loss exists in each engine component, and the sum losses of main combustion chamber(CC), pre-burner(PB), precooler(PC) and 3# heat exchanger(HX3) are greater than 71.3% of the total loss. Equivalence ratio is the main influencing factor of cycle, and it can be regulated by adjusting parameters of helium loop. Increase the maximum helium outlet temperature of PC by 50 K, the total assumption of hydrogen will be saved by 4.8%, and the cycle efficiency is advanced by 3% averagely in the trajectory. Helium recirculation scheme introduces a helium recirculation loop to increase local helium flow rate of PC. It turns out the total assumption of hydrogen will be saved by 9%, that's about 1740 kg, and the cycle efficiency is advanced by 5.6% averagely.
Influence of processing parameters on lattice parameters in laser deposited tool alloy steel
Energy Technology Data Exchange (ETDEWEB)
Sun, G.F., E-mail: gfsun82@gmail.com [Center for Laser-Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, 48109 (United States); School of Mechanical Engineering, Jiangsu University, Zhenjiang, Jiangsu, 212013 (China); Bhattacharya, S. [Center for Laser-Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, 48109 (United States); Dinda, G.P.; Dasgupta, A. [Center for Advanced Technologies, Focus: Hope, Detroit, MI, 48238 (United States); Mazumder, J. [Center for Laser-Aided Intelligent Manufacturing, University of Michigan, Ann Arbor, MI, 48109 (United States)
2011-06-15
Highlights: {yields} Orientation relationships among phases in the DMD are given. {yields} Martensite lattice parameters increased with laser specific energy. {yields} Austenite lattice parameters decreased with laser specific energy. - Abstract: Laser aided direct metal deposition (DMD) has been used to form AISI 4340 steel coating on the AISI 4140 steel substrate. The microstructural property of the DMD coating was analyzed by means of scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. Microhardness of the DMD was measured with a Vickers microhardness tester. Results indicate that DMD can be used to form dense AISI 4340 steel coatings on AISI 4140 steel substrate. The DMD coating is mainly composed of martensite and retained austenite. Consecutive thermal cycles have a remarkable effect on the microstructure of the plan view of the DMD coating and on the corresponding microhardness distribution. Orientation relationships among austenite, martensite and cementite in the DMD coating followed the ones in conventional heat treated steels. As the laser specific energy decreased, cooling rate increased, and martensite peaks broadened and shifted to a lower Bragg's angle. Also martensite lattice parameters increased and austenite lattice parameters decreased due to the above parameter change.
Influence of processing parameters on lattice parameters in laser deposited tool alloy steel
International Nuclear Information System (INIS)
Sun, G.F.; Bhattacharya, S.; Dinda, G.P.; Dasgupta, A.; Mazumder, J.
2011-01-01
Highlights: → Orientation relationships among phases in the DMD are given. → Martensite lattice parameters increased with laser specific energy. → Austenite lattice parameters decreased with laser specific energy. - Abstract: Laser aided direct metal deposition (DMD) has been used to form AISI 4340 steel coating on the AISI 4140 steel substrate. The microstructural property of the DMD coating was analyzed by means of scanning electron microscopy, transmission electron microscopy and X-ray diffractometry. Microhardness of the DMD was measured with a Vickers microhardness tester. Results indicate that DMD can be used to form dense AISI 4340 steel coatings on AISI 4140 steel substrate. The DMD coating is mainly composed of martensite and retained austenite. Consecutive thermal cycles have a remarkable effect on the microstructure of the plan view of the DMD coating and on the corresponding microhardness distribution. Orientation relationships among austenite, martensite and cementite in the DMD coating followed the ones in conventional heat treated steels. As the laser specific energy decreased, cooling rate increased, and martensite peaks broadened and shifted to a lower Bragg's angle. Also martensite lattice parameters increased and austenite lattice parameters decreased due to the above parameter change.
International Nuclear Information System (INIS)
Lin Bihong; Chen Jincan
2006-01-01
The influence of both the quantum degeneracy and the finite-rate heat transfer between the working substance and the heat reservoirs on the optimal performance of an irreversible Stirling cryogenic refrigeration cycle using an ideal Fermi or Bose gas as the working substance is investigated, based on the theory of statistical mechanics and thermodynamic properties of ideal quantum gases. The inherent regeneration losses of the cycle are analysed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. In particular, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit are discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Stirling refrigeration cycles working with the ideal quantum and classical gases are revealed
Multi-parameter fibre Bragg grating sensor-array for thermal vacuum cycling test
Cheng, L.; Ahlers, B.; Toet, P.; Casarosa, G.; Appolloni, M.
2017-11-01
Fibre Bragg Grating (FBG) sensor systems based on optical fibres are gaining interest in space applications. Studies on Structural Health Monitoring (SHM) of the reusable launchers using FBG sensors have been carried out in the Future European Space Transportation Investigations Programme (FESTIP). Increasing investment in the development on FBG sensor applications is foreseen for the Future Launchers Preparatory Programme (FLPP). TNO has performed different SHM measurements with FBGs including on the VEGA interstage [1, 2] in 2006. Within the current project, a multi-parameter FBG sensor array demonstrator system for temperature and strain measurements is designed, fabricated and tested under ambient as well as Thermal Vacuum (TV) conditions in a TV chamber of the European Space Agency (ESA), ESTEC site. The aim is the development of a multi-parameters measuring system based on FBG technology for space applications. During the TV tests of a Space Craft (S/C) or its subsystems, thermal measurements, as well as strain measurements are needed by the engineers in order to verify their prediction and to validate their models. Because of the dimensions of the test specimen and the accuracy requested to the measurement, a large number of observation/measuring points are needed. Conventional sensor systems require a complex routing of the cables connecting the sensors to their acquisition unit. This will add extra weight to the construction under test. FBG sensors are potentially light-weight and can easily be multiplexed in an array configuration. The different tasks comply of a demonstrator system design; its component selection, procurement, manufacturing and finally its assembly. The temperature FBG sensor is calibrated in a dedicated laboratory setup down to liquid nitrogen (LN2) temperature at TNO. A temperature-wavelength calibration curve is generated. After a test programme definition a setup in thermal vacuum is realised at ESA premises including a mechanical
International Nuclear Information System (INIS)
Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.
2014-01-01
In the present work, a tomographic technique based on Rayleigh to Compton scattering ratio (R/C) was studied using computational simulation in order to assess its application to breast cancer diagnosis. In this preliminary study, some parameters that affect the image quality were evaluated, such as: (i) energy beam, (ii) size and glandularity of the breast, and (iii) statistical count noise. The results showed that the R/C contrast increases with increasing photon energy and decreases with increasing glandularity of the sample. The statistical noise showed to be a significant parameter, although the quality of the obtained images was acceptable for a considerable range of noise level. The preliminary results suggest that the R/C tomographic technique has a potential of being applied as a complementary tool in the breast cancer diagnostic. - Highlights: ► A tomographic technique based on Rayleigh to Compton scattering ratio is proposed in order to study breast tissues. ► The Rayleigh to Compton scattering ratio technique is compared with conventional transmission technique. ► The influence of experimental parameters (energy, sample, detection system) is studied
Modeling the Multinationality and Other Socio-Political Aspects of the Nuclear Fuel Cycle
International Nuclear Information System (INIS)
Nguyen, Viet Phuong; Yim, Man Sung
2016-01-01
Nuclear fuel cycle is a complex process with numerous steps, which are influenced by both engineering and socio-economic factors. Therefore, as an interdisciplinary tool developed to study the dynamic complexity of a system, system dynamics has been used to simulate nuclear fuel cycle and to support the development of nuclear policies. A number of studies have been done in this area providing comprehensive view of nuclear fuel cycle in respect to the energy scenarios, material flows, and pricing mechanism. However, the effect of other socio-economic aspects like public acceptance, proliferation risks, or the transboundary nature of the nuclear fuel cycle have not been well illustrated by those previous researches. In order to inform decision makers of the suitability and sustainability of any nuclear fuel cycle option, a modeling tool has to adequately cover such issues. A system dynamics model of nuclear fuel cycle was developed in order to examine the trans-boundary and domestic effects related to the socio-economic aspect of the fuel cycle. The significance and coefficient of the socio-economic factors were determined using statistical analysis of historical data. Preliminary results show the definitive effect of such factors on the net benefit of the nuclear fuel cycle and its expansion in relation with the nuclear cooperation between the service provider and the end-user. Thus, future models need to incorporate such features in order to provide a more comprehensive look of the fuel cycle
Modeling the Multinationality and Other Socio-Political Aspects of the Nuclear Fuel Cycle
Energy Technology Data Exchange (ETDEWEB)
Nguyen, Viet Phuong; Yim, Man Sung [KAIST, Daejeon (Korea, Republic of)
2016-05-15
Nuclear fuel cycle is a complex process with numerous steps, which are influenced by both engineering and socio-economic factors. Therefore, as an interdisciplinary tool developed to study the dynamic complexity of a system, system dynamics has been used to simulate nuclear fuel cycle and to support the development of nuclear policies. A number of studies have been done in this area providing comprehensive view of nuclear fuel cycle in respect to the energy scenarios, material flows, and pricing mechanism. However, the effect of other socio-economic aspects like public acceptance, proliferation risks, or the transboundary nature of the nuclear fuel cycle have not been well illustrated by those previous researches. In order to inform decision makers of the suitability and sustainability of any nuclear fuel cycle option, a modeling tool has to adequately cover such issues. A system dynamics model of nuclear fuel cycle was developed in order to examine the trans-boundary and domestic effects related to the socio-economic aspect of the fuel cycle. The significance and coefficient of the socio-economic factors were determined using statistical analysis of historical data. Preliminary results show the definitive effect of such factors on the net benefit of the nuclear fuel cycle and its expansion in relation with the nuclear cooperation between the service provider and the end-user. Thus, future models need to incorporate such features in order to provide a more comprehensive look of the fuel cycle.
Crystallization and preliminary X-ray diffraction analysis of rat autotaxin
International Nuclear Information System (INIS)
Day, Jacqueline E.; Hall, Troii; Pegg, Lyle E.; Benson, Timothy E.; Hausmann, Jens; Kamtekar, Satwik
2010-01-01
Autotaxin (ATX), a pyrophosphatase/phosphodiesterase enzyme, is a promising drug target for many indications and is only distantly related to enzymes of previously determined structure. Here, the cloning, expression, purification, crystallization and preliminary diffraction analysis of ATX are reported. Rat autotaxin has been cloned, expressed, purified to homogeneity and crystallized via hanging-drop vapour diffusion using PEG 3350 as precipitant and ammonium iodide and sodium thiocyanate as salts. The crystals diffracted to a maximum resolution of 2.05 Å and belonged to space group P1, with unit-cell parameters a = 53.8, b = 63.3, c = 70.5 Å, α = 98.8, β = 106.2, γ = 99.8°. Preliminary X-ray diffraction analysis indicated the presence of one molecule per asymmetric unit, with a solvent content of 47%
Energy Technology Data Exchange (ETDEWEB)
Arreola, Rodrigo [Departamento de Bioquímica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-243, Mexico City 04510 (Mexico); Vega-Miranda, Anita [Instituto Nacional de Enfermedades Respiratorias, Calzada de Tlalpan 4502, México DF 14080 (Mexico); Gómez-Puyou, Armando; Pérez-Montfort, Ruy [Departamento de Bioquímica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-243, Mexico City 04510 (Mexico); Merino-Pérez, Enrique [Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apartado Postal 510-3, Cuernavaca, Morelos (Mexico); Torres-Larios, Alfredo, E-mail: torres@ifc.unam.mx [Departamento de Bioquímica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-243, Mexico City 04510 (Mexico)
2008-08-01
The gene-regulation factor PyrR from B. halodurans has been crystallized in two crystal forms. Preliminary crystallographic analysis showed that the protein forms tetramers in both space groups. The PyrR transcriptional regulator is widely distributed in bacteria. This RNA-binding protein is involved in the control of genes involved in pyrimidine biosynthesis, in which uridyl and guanyl nucleotides function as effectors. Here, the crystallization and preliminary X-ray diffraction analysis of two crystal forms of Bacillus halodurans PyrR are reported. One of the forms belongs to the monoclinic space group P2{sub 1} with unit-cell parameters a = 59.7, b = 87.4, c = 72.1 Å, β = 104.4°, while the other form belongs to the orthorhombic space group P22{sub 1}2{sub 1} with unit-cell parameters a = 72.7, b = 95.9, c = 177.1 Å. Preliminary X-ray diffraction data analysis and molecular-replacement solution revealed the presence of four and six monomers per asymmetric unit; a crystallographic tetramer is formed in both forms.
International Nuclear Information System (INIS)
Arreola, Rodrigo; Vega-Miranda, Anita; Gómez-Puyou, Armando; Pérez-Montfort, Ruy; Merino-Pérez, Enrique; Torres-Larios, Alfredo
2008-01-01
The gene-regulation factor PyrR from B. halodurans has been crystallized in two crystal forms. Preliminary crystallographic analysis showed that the protein forms tetramers in both space groups. The PyrR transcriptional regulator is widely distributed in bacteria. This RNA-binding protein is involved in the control of genes involved in pyrimidine biosynthesis, in which uridyl and guanyl nucleotides function as effectors. Here, the crystallization and preliminary X-ray diffraction analysis of two crystal forms of Bacillus halodurans PyrR are reported. One of the forms belongs to the monoclinic space group P2 1 with unit-cell parameters a = 59.7, b = 87.4, c = 72.1 Å, β = 104.4°, while the other form belongs to the orthorhombic space group P22 1 2 1 with unit-cell parameters a = 72.7, b = 95.9, c = 177.1 Å. Preliminary X-ray diffraction data analysis and molecular-replacement solution revealed the presence of four and six monomers per asymmetric unit; a crystallographic tetramer is formed in both forms
Actinide recycle potential in the integral fast reactor (IFR) fuel cycle
International Nuclear Information System (INIS)
Chang, Y.I.; Till, C.E.
1991-01-01
In the Integral Fast Reactor (IFR) development program, the entire reactor system -- reactor, fuel cycle, and waste process is being developed and optimized at the same time as a single integral entity. The use of metallic fuel in the IFR allows a radically improved fuel cycle technology. Based on the recent IFR process development, a preliminary assessment has been made to investigate the feasibility of further adapting pyrochemical processes to directly extract actinides from LWR spent fuel. The results of this assessment indicate very promising potential and two most promising flowsheet options have been identified for further research and development. This paper also summarizes current thinking on the rationale for actinide recycle, its ramifications on the geologic repository and the current high-level waste management plans, and the necessary development programs
Preliminary Investigation on Life Cycle Inventory of Powder Bed Fusion of Stainless Steel
Nyamekye, Patricia; Piili, Heidi; Leino, Maija; Salminen, Antti
Manufacturing of work pieces from stainless steel with laser additive manufacturing, known also as laser sintering or 3D printing may increase energy and material efficiency. The use of powder bed fusion offers advantages to make parts for dynamic applications of light weight and near-net-shape products. Due to these advantages among others, PBF may also reduce emissions and operational cost in various applications. However, there are only few life cycle assessment studies examining this subject despite its prospect to business opportunity. The application of Life Cycle Inventory (LCI) in Powder Bed Fusion (PBF) provides a distinct evaluation of material and energy consumption. LCI offers a possibility to improve knowledge of process efficiency. This study investigates effect of process sustainability in terms of raw material, energy and time consumption with PBF and CNC machining. The results of the experimental study indicated lower energy efficiency in the production process with PBF. This study revealed that specific energy consumption in PBF decreased when several components are built simultaneously than if they would be built individually. This is due to fact that energy consumption per part is lower. On the contrary, amount of energy needed to machine on part in case of CNC machining is lower when parts are done separately.
A guide to introducing burnup credit, preliminary version (English translation)
International Nuclear Information System (INIS)
Okuno, Hiroshi; Suyama, Kenya; Ryufuku, Susumu
2017-06-01
There is an ongoing discussion on the application of burnup credit to the criticality safety controls of facilities that treat spent fuels. With regard to such application of burnup credit in Japan, this document summarizes the current technical status of the prediction of the isotopic composition and criticality of spent fuels, as well as safety evaluation concerns and the current status of legal affairs. This report is an English translation of A Guide to Introducing Burnup Credit, Preliminary Version, originally published in Japanese as JAERI-Tech 2001-055 by the Nuclear Fuel Cycle Facility Safety Research Committee. (author)
Analytical estimations of limit cycle amplitude for delay-differential equations
Directory of Open Access Journals (Sweden)
Tamás Molnár
2016-09-01
Full Text Available The amplitude of limit cycles arising from Hopf bifurcation is estimated for nonlinear delay-differential equations by means of analytical formulas. An improved analytical estimation is introduced, which allows more accurate quantitative prediction of periodic solutions than the standard approach that formulates the amplitude as a square-root function of the bifurcation parameter. The improved estimation is based on special global properties of the system: the method can be applied if the limit cycle blows up and disappears at a certain value of the bifurcation parameter. As an illustrative example, the improved analytical formula is applied to the problem of stick balancing.
Changes in brain size during the menstrual cycle.
Directory of Open Access Journals (Sweden)
Georg Hagemann
Full Text Available BACKGROUND: There is increasing evidence for hormone-dependent modification of function and behavior during the menstrual cycle, but little is known about associated short-term structural alterations of the brain. Preliminary studies suggest that a hormone-dependent decline in brain volume occurs in postmenopausal, or women receiving antiestrogens, long term. Advances in serial MR-volumetry have allowed for the accurate detection of small volume changes of the brain. Recently, activity-induced short-term structural plasticity of the brain was demonstrated, challenging the view that the brain is as rigid as formerly believed. METHODOLOGY/PRINCIPAL FINDINGS: We used MR-volumetry to investigate short-term brain volume changes across the menstrual cycle in women or a parallel 4 week period in men, respectively. We found a significant grey matter volume peak and CSF loss at the time of ovulation in females. This volume peak did not correlate with estradiol or progesterone hormone levels. Men did not show any significant brain volume alterations. CONCLUSIONS/SIGNIFICANCE: These data give evidence of short-term hormone-dependent structural brain changes during the menstrual cycle, which need to be correlated with functional states and have to be considered in structure-associated functional brain research.
Operation of CANDU power reactor in thorium self-sufficient fuel cycle
Indian Academy of Sciences (India)
This paper presents the results of calculations for CANDU reactor operation in thorium fuel cycle. Calculations are performed to estimate the feasibility of operation of heavy-water thermal neutron power reactor in self-sufficient thorium cycle. Parameters of active core and scheme of fuel reloading were considered to be the ...
Towards evaluation and prediction of building sustainability using life cycle behaviour simulation
Directory of Open Access Journals (Sweden)
Marzouk Mohamed
2017-01-01
Full Text Available Nowadays researchers and practitioners are oriented towards questioning how effective are the different building life cycle activities contribution to preserving the environment and fulfilling the need for equilibrium. Terminologies such as Building sustainability and Green Buildings have long been adopted yet the evaluation of such has been driven through the use of rating systems. LEED of the United States, BREEAM of the United Kingdom, and Pearl of the United Arab Emirates are namely good examples of these rating systems. This paper introduces a new approach for evaluation of building life cycle sustainability through simulation of activities interaction and studying its behaviour. The effort focuses on comprehending impact and effect of suitability related activities over the whole building life cycle or period of time. The methodology includes gathering a pool of parameters through benchmarking of five selected rating systems, analytical factorization for the gathered parameters is used to elect the most influencing parameters. Followed by simulation modelling using System dynamics to capture the interaction of the considered parameters. The resulting behaviour obtained from simulation is studied and used in designing a tool for prediction of sustainability.
Study of the scenarios for the Cycle 12 of the Unit 1 of the CNLV
International Nuclear Information System (INIS)
Castillo, A.; Ortiz, J.J.; Montes, J.L.; Perusquia, R.
2005-01-01
In this work the preliminary results of a study of scenarios of it loads of fuel and operation of the Cycle 12 of the Unit 1 of the Laguna Verde power station are presented. Based on the Plan of Energy Use (PUE) for this cycle, they were studied different possibilities, with the idea to satisfy the energy demand under sure performance of the reactor. In this work were contemplated similar fuel assemblies to those that are using at the moment in the Cycle 11 of that unit. The reload proposals using the Haling principle and patterns of control bars with the intelligent technique not exhaustive well-known as taboo search are analyzed. The simulator Cm-Presto was used to evaluate the scenarios. This study even continuous analyzing different options and improving the results. (Author)
Assessment of the influence of design limits to the economics of WWER fuel cycle
International Nuclear Information System (INIS)
Dementiev, V.G.; Shishkov, L.K.
2010-01-01
The paper discusses the influence of the reactor parameters limits for normal operation on the economical performance of WWER fuel cycles. It is shown for the typical WWER fuel cycles that decreasing the limits for the main power distribution parameters to 10% leads to decreasing the fuel components of the electricity cost price up to 4-5%. As the nowadays limitations are reached the dependence becomes weaker. (Authors)
Bayesian Parameter Estimation for Heavy-Duty Vehicles
Energy Technology Data Exchange (ETDEWEB)
Miller, Eric; Konan, Arnaud; Duran, Adam
2017-03-28
Accurate vehicle parameters are valuable for design, modeling, and reporting. Estimating vehicle parameters can be a very time-consuming process requiring tightly-controlled experimentation. This work describes a method to estimate vehicle parameters such as mass, coefficient of drag/frontal area, and rolling resistance using data logged during standard vehicle operation. The method uses Monte Carlo to generate parameter sets which is fed to a variant of the road load equation. Modeled road load is then compared to measured load to evaluate the probability of the parameter set. Acceptance of a proposed parameter set is determined using the probability ratio to the current state, so that the chain history will give a distribution of parameter sets. Compared to a single value, a distribution of possible values provides information on the quality of estimates and the range of possible parameter values. The method is demonstrated by estimating dynamometer parameters. Results confirm the method's ability to estimate reasonable parameter sets, and indicates an opportunity to increase the certainty of estimates through careful selection or generation of the test drive cycle.
Activity cycles in members of young loose stellar associations
Distefano, E.; Lanzafame, A. C.; Lanza, A. F.; Messina, S.; Spada, F.
2017-10-01
Context. Magnetic cycles analogous to the solar cycle have been detected in tens of solar-like stars by analyzing long-term time series of different magnetic activity indexes. The relationship between the cycle properties and global stellar parameters is not fully understood yet. One reason for this is the lack of long-term time series for stars covering a wide range of stellar parameters. Aims: We searched for activity cycles in a sample of 90 young solar-like stars with ages between 4 and 95 Myr with the aim to investigate the properties of activity cycles in this age range. Methods: We measured the length Pcyc of a given cycle by analyzing the long-term time series of three different activity indexes: the period of rotational modulation, the amplitude of the rotational modulation and the median magnitude in the V band. For each star, we also computed the global magnetic activity index ⟨ IQR ⟩ that is proportional to the amplitude of the rotational modulation and can be regarded as a proxy of the mean level of the surface magnetic activity. Results: We detected activity cycles in 67 stars. Secondary cycles were also detected in 32 stars of the sample. The lack of correlation between Pcyc and Prot and the position of our targets in the Pcyc/Prot-Ro-1 diagram suggest that these stars belong to the so-called transitional branch and that the dynamo acting in these stars is different from the solar dynamo and from that acting in the older Mt. Wilson stars. This statement is also supported by the analysis of the butterfly diagrams whose patterns are very different from those seen in the solar case. We computed the Spearman correlation coefficient rS between Pcyc, ⟨ IQR ⟩ and various stellar parameters. We found that Pcyc in our sample is uncorrelated with all the investigated parameters. The ⟨ IQR ⟩ index is positively correlated with the convective turnover timescale, the magnetic diffusivity timescale τdiff, and the dynamo number DN, whereas it is anti
Nuclear fuel cycle cost analysis using a probabilistic simulation technique
International Nuclear Information System (INIS)
Won, Il Ko; Jong, Won Choi; Chul, Hyung Kang; Jae, Sol Lee; Kun, Jai Lee
1998-01-01
A simple approach was described to incorporate the Monte Carlo simulation technique into a fuel cycle cost estimate. As a case study, the once-through and recycle fuel cycle options were tested with some alternatives (ie. the change of distribution type for input parameters), and the simulation results were compared with the values calculated by a deterministic method. A three-estimate approach was used for converting cost inputs into the statistical parameters of assumed probabilistic distributions. It was indicated that the Monte Carlo simulation by a Latin Hypercube Sampling technique and subsequent sensitivity analyses were useful for examining uncertainty propagation of fuel cycle costs, and could more efficiently provide information to decisions makers than a deterministic method. It was shown from the change of distribution types of input parameters that the values calculated by the deterministic method were set around a 40 th ∼ 50 th percentile of the output distribution function calculated by probabilistic simulation. Assuming lognormal distribution of inputs, however, the values calculated by the deterministic method were set around an 85 th percentile of the output distribution function calculated by probabilistic simulation. It was also indicated from the results of the sensitivity analysis that the front-end components were generally more sensitive than the back-end components, of which the uranium purchase cost was the most important factor of all. It showed, also, that the discount rate made many contributions to the fuel cycle cost, showing the rank of third or fifth of all components. The results of this study could be useful in applications to another options, such as the Dcp (Direct Use of PWR spent fuel In Candu reactors) cycle with high cost uncertainty
Trends and solar cycle effects in mesospheric ice clouds
Lübken, Franz-Josef; Berger, Uwe; Fiedler, Jens; Baumgarten, Gerd; Gerding, Michael
Lidar observations of mesospheric ice layers (noctilucent clouds, NLC) are now available since 12 years which allows to study solar cycle effects on NLC parameters such as altitudes, bright-ness, and occurrence rates. We present observations from our lidar stations in Kuehlungsborn (54N) and ALOMAR (69N). Different from general expectations the mean layer characteris-tics at ALOMAR do not show a persistent anti-correlation with solar cycle. Although a nice anti-correlation of Ly-alpha and occurrence rates is detected in the first half of the solar cycle, occurrence rates decreased with decreasing solar activity thereafter. Interestingly, in summer 2009 record high NLC parameters were detected as expected in solar minimum conditions. The morphology of NLC suggests that other processes except solar radiation may affect NLC. We have recently applied our LIMA model to study in detail the solar cycle effects on tempera-tures and water vapor concentration the middle atmosphere and its subsequent influence on mesospheric ice clouds. Furthermore, lower atmosphere effects are implicitly included because LIMA nudges to the conditions in the troposphere and lower stratosphere. We compare LIMA results regarding solar cycle effects on temperatures and ice layers with observations at ALO-MAR as well as satellite borne measurements. We will also present LIMA results regarding the latitude variation of solar cycle and trends, including a comparison of northern and southern hemisphere. We have adapted the observation conditions from SBUV (wavelength and scatter-ing angle) in LIMA for a detailed comparison with long term observations of ice clouds from satellites.
Effect of pneumatic compressing powered orthosis in stroke patients: preliminary study.
Kim, Eun Sil; Yoon, Yong-Soon; Sohn, Min Kyun; Kwak, Soo-Hyun; Choi, Jong Ho; Oh, Ji Sun
2015-04-01
To evaluate the feasibility and effectiveness of a knee-ankle-foot orthosis powered by artificial pneumatic muscles (PKAFO). Twenty-three hemiplegic patients (age, 59.6±13.7 years) were assessed 19.7±36.6 months after brain lesion. The 10-m walking time was measured as a gait parameter while the individual walked on a treadmill. Walking speed (m/s), step cycle (cycle/s), and step length (m) were also measured on a treadmill with and without PKAFO, and before and after gait training. Clinical parameters measured before and after gait training included Korean version of Modified Bathel Index (K-MBI), manual muscle test (MMT), and Modified Ashworth Scale (MAS) of hemiplegic ankle. Gait training comprised treadmill walking for 20 minutes, 5 days a week for 3 weeks at a comfortable speed. The 10-m walking time, walking speed, step length, and step cycle were significantly greater with PKAFO than without PKAFO, and after gait training (both p<0.05). K-MBI was improved after gait training (p<0.05), but MMT and MAS were not. PKAFO may improve gait function in hemiplegic patients. It can be a useful orthosis for gait training in hemiplegic patients.
Nuclear Fuel Cycle Evaluation and Real Options
Directory of Open Access Journals (Sweden)
L. Havlíček
2008-01-01
Full Text Available The first part of this paper describes the nuclear fuel cycle. It is divided into three parts. The first part, called Front-End, covers all activities connected with fuel procurement and fabrication. The middle part of the cycle includes fuel reload design activities and the operation of the fuel in the reactor. Back-End comprises all activities ensuring safe separation of spent fuel and radioactive waste from the environment. The individual stages of the fuel cycle are strongly interrelated. Overall economic optimization is very difficult. Generally, NPV is used for an economic evaluation in the nuclear fuel cycle. However the high volatility of uranium prices in the Front-End, and the large uncertainty of both economic and technical parameters in the Back-End, make the use of NPV difficult. The real option method is able to evaluate the value added by flexibility of decision making by a company under conditions of uncertainty. The possibility of applying this method to the nuclear fuel cycle evaluation is studied.
Kinetic parameters for source driven systems
International Nuclear Information System (INIS)
Dulla, S.; Ravetto, P.; Carta, M.; D'Angelo, A.
2006-01-01
The definition of the characteristic kinetic parameters of a subcritical source-driven system constitutes an interesting problem in reactor physics with important consequences for practical applications. Consistent and physically meaningful values of the parameters allow to obtain accurate results from kinetic simulation tools and to correctly interpret kinetic experiments. For subcritical systems a preliminary problem arises for the adoption of a suitable weighting function to be used in the projection procedure to derive a point model. The present work illustrates a consistent factorization-projection procedure which leads to the definition of the kinetic parameters in a straightforward manner. The reactivity term is introduced coherently with the generalized perturbation theory applied to the source multiplication factor ks, which is thus given a physical role in the kinetic model. The effective prompt lifetime is introduced on the assumption that a neutron generation can be initiated by both the fission process and the source emission. Results are presented for simplified configurations to fully comprehend the physical features and for a more complicated highly decoupled system treated in transport theory. (authors)
Johnson, K. S.; Plant, J. N.; Sakamoto, C.; Coletti, L. J.; Sarmiento, J. L.; Riser, S.; Talley, L. D.
2016-12-01
Sixty profiling floats with ISUS and SUNA nitrate sensors have been deployed in the Southern Ocean (south of 30 degrees S) as part of the SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) program and earlier efforts. These floats have produced detailed records of the annual cycle of nitrate concentration throughout the region from the surface to depths near 2000 m. In surface waters, there are clear cycles in nitrate concentration that result from uptake of nitrate during austral spring and summer. These changes in nitrate concentration were used to compute the annual net community production over this region. NCP was computed using a simplified version of the approach detailed by Plant et al. (2016, Global Biogeochemical Cycles, 30, 859-879, DOI: 10.1002/2015GB005349). At the time the abstract was written 41 complete annual cycles were available from floats deployed before the austral summer of 2015/2016. After filtering the data to remove floats that crossed distinct frontal boundaries, floats with other anomalies, and floats in sub-tropical waters, 23 cycles were available. A preliminary assessment of the data yields an NCP of 2.8 +/- 0.95 (1 SD) mol C/m2/y after integrating to 100 m depth and converting nitrate uptake to carbon using the Redfield ratio. This preliminary assessment ignores vertical transport across the nitracline and is, therefore, a minimum estimate. The number of cycles available for analysis will increase rapidly, as 32 of the floats were deployed in the austral summer of 2015/2016 and have not yet been analyzed.
Preliminary Phytochemical Evaluation of Seed Extracts of Cucurbita Maxima Duchense
Ashok Sharma; Ashish K. Sharma; Tara Chand; Manoj Khardiya; Kailash Chand Yadav
2013-01-01
Cucurbita maxima Duchense (family:Cucurbitaceae) is a trailing annual herb, widely cultivated throughout India and in most warm regions of the world, for used as vegetables as well as medicines. The present study deals with preliminary physicochemical and phytochemical evaluation of seed extract of Cucurbita maxima. The study includes preparation of different extracts by successive solvent extraction for detailed analysis. Different physicochemical parameters such as ash value (total ash, aci...
Are climatological correlations with the Hale double sunspot cycle meaningful
International Nuclear Information System (INIS)
Goldberg, R.A.; Herman, J.R.
1975-09-01
A sunspot cycle which may have been subject to a predicted phase reversal between 1800 and 1880 A.D. is discussed. Several climatological parameters normally correlated with this cycle are examined and do not exhibit a corresponding phase reversal during this period. It is proposed that this apparent discrepency can be resolved by suitable observations during the upcoming half decade
Effect of engine parameters and gaseous fuel type on the cyclic variability of dual fuel engines
Energy Technology Data Exchange (ETDEWEB)
Mohamed Y.E. Selim [United Arab Emirates University, Al-Ain (United Arab Emirates). Mechanical Engineering Department, Faculty of Engineering
2005-05-01
This paper presents an analysis of the cycle-to-cycle combustion variation as reflected in the combustion pressure data of a single cylinder, naturally aspirated, four stroke, Ricardo E6 engine converted to run as dual fuel engine on diesel and gaseous fuel of LPG or methane. A measuring set-up consisting of a piezo-electric pressure transducer with charge amplifier and fast data acquisition card installed on an IBM microcomputer was used to gather the data of up to 1200 consecutive combustion cycles of the cylinder under various combination of engine operating and design parameters. These parameters included type of gaseous fuel, engine load, compression ratio, pilot fuel injection timing, pilot fuel mass, and engine speed. The data for each operating conditions were analyzed for the maximum pressure, the maximum rate of pressure rise representing the combustion noise, and indicated mean effective pressure. The cycle-to-cycle variation is expressed as the mean value, standard deviation, and coefficient of variation of these three parameters. It was found that the type of gaseous fuel and engine operating and design parameters affected the combustion noise and its cyclic variation and these effects have been presented. 21 refs., 6 figs., 1 tab.
The study of the energetic performance in test cycles
Rentea, Cristian; Tuca, Alexandra; Oprean, Mircea; Marius, Bataus
2017-10-01
One of the most important subsystems of modern passenger cars is the transmission. This paper aims to investigate the global performances of a modern transmission in different test cycles including the newly introduced WLTC (Worldwide Harmonized Light Vehicles Test Cycle). The study is done using a complex model developed in a performant simulation environment. Transmission efficiency calculation is emphasized, the efficiency being considered variable depending on engine torque, engine speed and gear ratio. The main important parameters (vehicle speed fluctuation, overall transmission efficiency, fuel consumption ratio) needed to compare test cycles and the transmissions performance are determined.
Analysis of thermal cycles and working fluids for power generation in space
International Nuclear Information System (INIS)
Tarlecki, Jason; Lior, Noam; Zhang Na
2007-01-01
Production of power in space for terrestrial use is of great interest in view of the rapidly rising power demand and its environmental impacts. Space also offers a very low temperature, making it a perfect heat sink for power plants, thus offering much higher efficiencies. This paper focuses on the evaluation and analysis of thermal Brayton, Ericsson and Rankine power cycles operating at space conditions on several appropriate working fluids. Under the examined conditions, the thermal efficiency of Brayton cycles reaches 63%, Ericsson 74%, and Rankine 85%. These efficiencies are significantly higher than those for the computed or real terrestrial cycles: by up to 45% for the Brayton, and 17% for the Ericsson; remarkably 44% for the Rankine cycle even when compared with the best terrestrial combined cycles. From the considered working fluids, the diatomic gases (N 2 and H 2 ) produce somewhat better efficiencies than the monatomic ones in the Brayton and Rankine cycles. The Rankine cycles require radiator areas that are larger by up to two orders of magnitude than those required for the Brayton and Ericsson cycles. The results of the analysis of the sensitivity of the cycle performance parameters to major parameters such as turbine inlet temperature and pressure ratio are presented, equations or examining the effects of fluid properties on the radiator area and pressure drop were developed, and the effects of the working fluid properties on cycle efficiency and on the power production per unit radiator area were explored to allow decisions on the optimal choice of working fluids
Fuel reprocessing: safety analysis of extraction cycles
International Nuclear Information System (INIS)
Dinh, B.; Mauborgne, B.; Baron, P.; Mercier, J.P.
1991-01-01
An essential part of the safety analysis related to the extraction cycles of reprocessing plants, is the analysis of their behaviour during steady-state and transient operations, by means of simulation codes. These codes are based on the chemical properties of the main species involved (distribution coefficient and kinetics) and the hydrodynamics inside the contactors (mixer-settlers and pulsed columns). These codes have been consolidated by comparison of calculations with experimental results. The safety analysis is essentially performed in two steps. The first step is a parametric sensitivity analysis of the chemical flowsheet operated: the effect of a misadjustment (flowrate of feed, solvent, etc) is evaluated by successive steady-state calculations. These calculations help the identification of the sensitive parameters for the risk of plutonium accumulation, while indicating the permissible level of misadjustment. These calculations also serve to identify the parameters which should be measured during plant operation. The second step is the study of transient regimes, for the most sensitive parameters related to plutonium accumulation risk. The aim is to confirm the conclusions of the first step and to check that the characteristic process parameters chosen effectively allow, the early and reliable detection of any drift towards a plutonium accumulating regime. The procedures to drive the process backwards to a specified convenient steady-state regime from a drifting-state are also verified. The identification of the sensitive parameters, the process status parameters and the process transient analysis, allow a good control of process operation. This procedure, applied to the first purification cycle of COGEMA's UP3-A La Hague plant has demonstrated the total safety of facility operations
Energy Expenditure of Trotting Gait Under Different Gait Parameters
Chen, Xian-Bao; Gao, Feng
2017-07-01
Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, optimal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is proposed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.
Plant characteristics of an integrated solid oxide fuel cell cycle and a steam cycle
International Nuclear Information System (INIS)
Rokni, Masoud
2010-01-01
Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine cycle in a heat recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization and the pre-reformer had no effect on the plant efficiency, which was also true when decreasing the anode temperature. However, increasing the cathode temperature had a significant effect on the plant efficiency. In addition, decreasing the SOFC utilization factor from 0.8 to 0.7, increases the plant efficiency by about 6%. An optimal plant efficiency of about 71% was achieved by optimizing the plant.
Plant characteristics of an integrated solid oxide fuel cell cycle and a steam cycle
Energy Technology Data Exchange (ETDEWEB)
Rokni, Masoud [Technical University of Denmark, Dept. of Mechanical Engineering, Thermal Energy System, Building 402, 2800 Kgs, Lyngby (Denmark)
2010-12-15
Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine cycle in a heat recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization and the pre-reformer had no effect on the plant efficiency, which was also true when decreasing the anode temperature. However, increasing the cathode temperature had a significant effect on the plant efficiency. In addition, decreasing the SOFC utilization factor from 0.8 to 0.7, increases the plant efficiency by about 6%. An optimal plant efficiency of about 71% was achieved by optimizing the plant. (author)
Economic analysis of fast reactor fuel cycle with different modes
International Nuclear Information System (INIS)
Ding Xiaoming
2014-01-01
Because of limitations on the access to technical and economic data and the lack of effective verification, the lack of in-depth study on the economy of fast reactor fuel cycle in China. This paper introduces the analysis and calculation results of the levelized cost of electricity (LCOE) under three different fuel cycle modes including fast reactor fuel cycle carried out by Massachusetts Institute of Technology (MIT). The author used the evaluation method and hypothesis parameters provided by the MIT to carry out the sensitivity analysis for the impact of the overnight cost, the discount rate and changes of uranium price on the LCOE under three fuel cycle modes. Finally, some suggestions are proposed on the study of economy in China's fast reactor fuel cycle. (authors)
Endogenous Business Cycle Dynamics within Metzlers Inventory Model: Adding an Inventory Floor.
Sushko, Irina; Wegener, Michael; Westerhoff, Frank; Zaklan, Georg
2009-04-01
Metzlers inventory model may produce dampened fluctuations in economic activity, thus contributing to our understanding of business cycle dynamics. For some parameter combinations, however, the model generates oscillations with increasing amplitude, implying that the inventory stock of firms eventually turns negative. Taking this observation into account, we reformulate Metzlers model by simply putting a floor to the inventory level. Within the new piecewise linear model, endogenous business cycle dynamics may now be triggered via a center bifurcation, i.e. for certain parameter combinations production changes are (quasi-)periodic.
International Nuclear Information System (INIS)
Wang Hao; Liu Sanqiu
2008-01-01
An irreversible cycle model of magnetic Brayton refrigerators is established, in which the thermal resistance and irreversibility in the two adiabatic processes are taken into account. Expressions for several important performance parameters, such as the coefficient of performance, cooling rate and power input are derived. Moreover, the optimal performance parameters are obtained at the maximum coefficient of performance. The optimization region (or criteria) for an irreversible magnetic Brayton refrigerator is obtained. The results obtained here have general significance and will be helpful to understand deeply the performance of a magnetic Brayton refrigeration cycle
Simplified procedures for fast reactor fuel cycle and sensitivity analysis
International Nuclear Information System (INIS)
Badruzzaman, A.
1979-01-01
The Continuous Slowing Down-Integral Transport Theory has been extended to perform criticality calculations in a Fast Reactor Core-blanket system achieving excellent prediction of the spectrum and the eigenvalue. The integral transport parameters did not need recalculation with source iteration and were found to be relatively constant with exposure. Fuel cycle parameters were accurately predicted when these were not varied, thus reducing a principal potential penalty of the Intergal Transport approach where considerable effort may be required to calculate transport parameters in more complicated geometries. The small variation of the spectrum in the central core region, and its weak dependence on exposure for both this region, the core blanket interface and blanket region led to the extension and development of inexpensive simplified procedures to complement exact methods. These procedures gave accurate predictions of the key fuel cycle parameters such as cost and their sensitivity to variation in spectrum-averaged and multigroup cross sections. They also predicted the implications of design variation on these parameters very well. The accuracy of these procedures and their use in analyzing a wide variety of sensitivities demonstrate the potential utility of survey calculations in Fast Reactor analysis and fuel management
International Nuclear Information System (INIS)
Al-Hinti, I.; Akash, B.; Abu-Nada, E.; Al-Sarkhi, A.
2008-01-01
This study presents the investigation of air-standard Diesel cycle under irreversible heat transfer conditions. The effects of various engine parameters are presented. An alternative approach is used to evaluate net power output and cycle thermal efficiency from more realistic parameters such as air-fuel ratio, fuel mass flow rate, intake temperature, engine design parameters, etc. It is shown that for a given fuel flow rate, thermal efficiency and maximum power output increase with decreasing air-fuel ratio. Also, for a given air-fuel ratio, the maximum power output increases with increasing fuel rate. However, the effect of the thermal efficiency is limited
Sunspot Cycle Prediction Using Multivariate Regression and Binary ...
Indian Academy of Sciences (India)
49
Multivariate regression model has been derived based on the available cycles 1 .... The flare index correlates well with various parameters of the solar activity. ...... 32) Sabarinath A and Anilkumar A K 2011 A stochastic prediction model for the.
An overview of R and D activities for the Cu-Cl, cycle with emphasis on the hydrolysis reaction
International Nuclear Information System (INIS)
Lewis, M.A.; Ferrandon, M.S.; Tatterson, D.F.
2010-01-01
This paper describes the status of the development effort for the Cu-Cl thermochemical cycle. Most of the recent work has been focused on the hydrolysis reaction, which is challenging because of the need for excess steam to achieve high yields. Two types of spray reactors were tested and the ultrasonic nozzle gave excellent results. The conceptual process design for the overall process now includes a spray reactor. Engineering methods to increase efficiency are proposed. Preliminary values for the efficiency and capital costs for producing hydrogen using the Cu-Cl cycle have been calculated. (authors)
Directory of Open Access Journals (Sweden)
Toichiro Asada
2007-01-01
Full Text Available We explore numerically a three-dimensional discrete-time Kaldorian macrodynamic model in an open economy with fixed exchange rates, focusing on the effects of variation of the model parameters, the speed of adjustment of the goods market α, and the degree of capital mobility β on the stability of equilibrium and on the existence of business cycles. We determine the stability region in the parameter space and find that increase of α destabilizes the equilibrium more quickly than increase of β. We determine the Hopf-Neimark bifurcation curve along which business cycles are generated, and discuss briefly the occurrence of Arnold tongues. Bifurcation and Lyapunov exponent diagrams are computed providing information on the emergence, persistence, and amplitude of the cycles and illustrating the complex dynamics involved. Examples of cycles and other attractors are presented. Finally, we discuss a two-dimensional variation of the model related to a “wealth effect,” called model 2, and show that in this case, α does not destabilize the equilibrium more quickly than β, and that a Hopf-Neimark bifurcation curve does not exist in the parameter space, therefore model 2 does not produce cycles.
Using neuro-fuzzy based method to develop nuclear turbine cycle model
International Nuclear Information System (INIS)
Chan Yeakuang; Chang Chinjang
2009-01-01
The purpose of this study is to describe a hybrid soft-computing modeling technique used to develop the steam turbine cycle model for nuclear power plants. The technique uses neuro-fuzzy model to predict the generator output. Firstly, the plant past three fuel cycles operating data above 95% load were collected and validated as the baseline performance data set. Then the signal errors for new operating data were detected by comparison with the baseline data set and their allowable range of variations. Finally, the most important parameters were selected as an input of the neuro-fuzzy based steam turbine cycle model. After training and testing with key parameters (i.e. throttle pressure, condenser backpressure, feedwater flow rate, and final feedwater temperature), the proposed model can be used to predict the generator output. The analysis results show this neuro-fuzzy based turbine cycle model can be used to predict the generator output with a good agreement. Moreover, the achievement of this study provides an alternative approach in thermal performance evaluation for nuclear power plants. (author)
Volume reduction technology development for solid wastes from the nuclear fuel cycle
International Nuclear Information System (INIS)
Oh, Won Zin; Lee, Kune Woo; Song, Kee Chan; Choi, Wang Kyu; Kim, Young Min
1998-07-01
A great deal of solid wastes, which have various physical, chemical, and radiological characteristics, are generated from the nuclear fuel cycle facility as well as radioactive gaseous and liquid wastes. The treatment of the large quantity of solid wastes from the nuclear fuel cycle have great technical, economical and social effects on the domestic policy decision on the nuclear fuel cycle, such as operation and maintenance of the facility, waste disposal, etc. Cement immobilization, super compaction, and electrochemical dissolution were selected as the volume reduction technologies for solid wastes, which will generated from the domestic nuclear fuel cycle facility in the future. And the assessment of annual arisings and the preliminary conceptual design of volume reduction processes were followed. Electrochemical decontamination of α-radionuclides from the spent fuel hulls were experimentally investigated, and showed the successful results. However, β/γ radioactivity did not reduce to the level below which hulls can be classified as the low-level radioactive waste and sent to the disposal site for the shallow land burial. The effects of the various process variables in the electrochemical decontamination were experimentally analysed on the process. (author). 32 refs., 32 tabs., 52 figs
Plasma brake model for preliminary mission analysis
Orsini, Leonardo; Niccolai, Lorenzo; Mengali, Giovanni; Quarta, Alessandro A.
2018-03-01
Plasma brake is an innovative propellantless propulsion system concept that exploits the Coulomb collisions between a charged tether and the ions in the surrounding environment (typically, the ionosphere) to generate an electrostatic force orthogonal to the tether direction. Previous studies on the plasma brake effect have emphasized the existence of a number of different parameters necessary to obtain an accurate description of the propulsive acceleration from a physical viewpoint. The aim of this work is to discuss an analytical model capable of estimating, with the accuracy required by a preliminary mission analysis, the performance of a spacecraft equipped with a plasma brake in a (near-circular) low Earth orbit. The simplified mathematical model is first validated through numerical simulations, and is then used to evaluate the plasma brake performance in some typical mission scenarios, in order to quantify the influence of the system parameters on the mission performance index.
International Nuclear Information System (INIS)
Yoshimura, H.
1979-01-01
A new dynamical model of the solar cycle has predicted that the cycle should have a hysteretic nature: the behavior of each 11 year cycle should depend on previous cycles. In the light of this new understanding of the dynamical mechanism of the solar cycle, Waldmeier's (hypothetical) law was examined as a yet unexplained characteristic of the cycle by studying the observed sunspot frequency curve. Contrary to this hypothetical law, however, it was found that sunspot cycle curves did not form a single-parameter family characterized by the maximum amplitude of the cycle. The evolutionary trajectories in period-amplitude phase space verified the hysteretic nature of the observed cycle and revealed long-term (55 year instead of the previously claimed 80 year) periodic modulations, called here 55 year grand cycles. Each 55 year grand cycle forms a loop in the phase space, and the characteristics of each 11 year cycle depend on its position in the ascending or descending phase of the grand cycle. This new law was analyzed by the nonlinear multiple-period dynamo oscillation model which has predicted the hysteretic nature. The era from cycle 11 to cycle 15 turned out to be an anomalous one characterized by alternating amplitudes for odd and even cycles. Cycles 16--20 seem to constitute one grand cycle. If this is true, cycle 21 would be the beginning of another grand maximum and the model predicts that its duration would be short
Menstrual cycle phase does not predict political conservatism.
Directory of Open Access Journals (Sweden)
Isabel M Scott
Full Text Available Recent authors have reported a relationship between women's fertility status, as indexed by menstrual cycle phase, and conservatism in moral, social and political values. We conducted a survey to test for the existence of a relationship between menstrual cycle day and conservatism. 2213 women reporting regular menstrual cycles provided data about their political views. Of these women, 2208 provided information about their cycle date, 1260 provided additional evidence of reliability in self-reported cycle date, and of these, 750 also indicated an absence of hormonal disruptors such as recent hormonal contraception use, breastfeeding or pregnancy. Cycle day was used to estimate day-specific fertility rate (probability of conception; political conservatism was measured via direct self-report and via responses to the "Moral Foundations" questionnaire. We also recorded relationship status, which has been reported to interact with menstrual cycle phase in determining political preferences. We found no evidence of a relationship between estimated cyclical fertility changes and conservatism, and no evidence of an interaction between relationship status and cyclical fertility in determining political attitudes. Our findings were robust to multiple inclusion/exclusion criteria and to different methods of estimating fertility and measuring conservatism. In summary, the relationship between cycle-linked reproductive parameters and conservatism may be weaker or less reliable than previously thought.
Menstrual cycle phase does not predict political conservatism.
Scott, Isabel M; Pound, Nicholas
2015-01-01
Recent authors have reported a relationship between women's fertility status, as indexed by menstrual cycle phase, and conservatism in moral, social and political values. We conducted a survey to test for the existence of a relationship between menstrual cycle day and conservatism. 2213 women reporting regular menstrual cycles provided data about their political views. Of these women, 2208 provided information about their cycle date, 1260 provided additional evidence of reliability in self-reported cycle date, and of these, 750 also indicated an absence of hormonal disruptors such as recent hormonal contraception use, breastfeeding or pregnancy. Cycle day was used to estimate day-specific fertility rate (probability of conception); political conservatism was measured via direct self-report and via responses to the "Moral Foundations" questionnaire. We also recorded relationship status, which has been reported to interact with menstrual cycle phase in determining political preferences. We found no evidence of a relationship between estimated cyclical fertility changes and conservatism, and no evidence of an interaction between relationship status and cyclical fertility in determining political attitudes. Our findings were robust to multiple inclusion/exclusion criteria and to different methods of estimating fertility and measuring conservatism. In summary, the relationship between cycle-linked reproductive parameters and conservatism may be weaker or less reliable than previously thought.
International Nuclear Information System (INIS)
Hill, M.D.
1979-06-01
A preliminary assessment of the radiological consequences of geologic disposal of high-level waste (Hill and Grimwood. NRPB-R69 (1978)) identified several areas where further research is required before this disposal option can be fully evaluated. This report is an analysis of the sensitivity of the results of the preliminary assessment to the assumptions made and the values of the parameters used. The parameters considered include the leach rate of the waste, the ground-water velocity, the length of the flow path from the repository to a source of drinking water and the sorption constants of the principle radionuclides. The results obtained by varying these parameters are used to examine the effects of assumptions such as the time at which leaching of the waste begins. The sensitivity analysis shows the relative importance of the waste canisters, the waste form and the geologic barrier to radionuclide migration in determining potential doses. These results are used to identify research priorities, establish preliminary design criteria and indicate developments needed in the mathematical modelling of the movement of radionuclides from a repository to the biosphere. (author)
International Nuclear Information System (INIS)
Kim, Myung-Hyun; Kim, Kwan-Hee; Kim, Young-il
2004-01-01
A design concept of pressure-tube type light water cooled reactor (HCPLWR) core was proposed as a thermal high-conversion reactor using a thorium based once-through cycle strategy. In a previous work, fuel cycle economics and nuclear safety were confirmed. In this work, HCPLWR was evaluated in the aspects of proliferation resistance and transmutation capability. Evaluation was done as a direct comparison of indices with PWR, CANDU and Radkowsky Thorium Fuel (RTF). Conversion ratio was measured by fissile inventory ratio and fissile gain. Proliferation resistance of plutonium composition from spent seed and blanket fuels was measured by bare critical mass, spontaneous neutron source rate, and thermal heat generation rate. For the evaluation of long-lived minor actinide transmutation was measured by a new parameter, effective fission half-life. Two-dimensional calculation for the assembly-wise unit module showed each parameter values. Even though conversion capability of HCPLWR was higher than one of RTF, it was concluded that current HCPLWR design was not favorable than RTF. Design optimization is required for the future work. (author)
Parameter assessment for virtual Stackelberg game in aerodynamic shape optimization
Wang, Jing; Xie, Fangfang; Zheng, Yao; Zhang, Jifa
2018-05-01
In this paper, parametric studies of virtual Stackelberg game (VSG) are conducted to assess the impact of critical parameters on aerodynamic shape optimization, including design cycle, split of design variables and role assignment. Typical numerical cases, including the inverse design and drag reduction design of airfoil, have been carried out. The numerical results confirm the effectiveness and efficiency of VSG. Furthermore, the most significant parameters are identified, e.g. the increase of design cycle can improve the optimization results but it will also add computational burden. These studies will maximize the productivity of the effort in aerodynamic optimization for more complicated engineering problems, such as the multi-element airfoil and wing-body configurations.
Jackson, R. J.; Wang, T. T.
1974-01-01
A computer program was developed to describe the performance of ramjet and scramjet cycles. The program performs one dimensional calculations of the equilibrium, real-gas internal flow properties of the engine. The program can be used for the following: (1) preliminary design calculation and (2) design analysis of internal flow properties corresponding to stipulated flow areas. Only the combustion of hydrogen in air is considered in this case.
International Nuclear Information System (INIS)
Dai Yiping; Wang Jiangfeng; Gao Lin
2009-01-01
A new combined power and refrigeration cycle is proposed, which combines the Rankine cycle and the ejector refrigeration cycle. This combined cycle produces both power output and refrigeration output simultaneously. It can be driven by the flue gas of gas turbine or engine, solar energy, geothermal energy and industrial waste heats. An exergy analysis is performed to guide the thermodynamic improvement for this cycle. And a parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the performance of the combined cycle. In addition, a parameter optimization is achieved by means of genetic algorithm to reach the maximum exergy efficiency. The results show that the biggest exergy loss due to the irreversibility occurs in heat addition processes, and the ejector causes the next largest exergy loss. It is also shown that the turbine inlet pressure, the turbine back pressure, the condenser temperature and the evaporator temperature have significant effects on the turbine power output, refrigeration output and exergy efficiency of the combined cycle. The optimized exergy efficiency is 27.10% under the given condition.
Preliminary conceptual study of engineering-scale pyroprocess demonstration facility
International Nuclear Information System (INIS)
Moon, Seong-In; Chong, Won-Myung; You, Gil-Sung; Ku, Jeong-Hoe; Kim, Ho-Dong
2013-01-01
Highlights: ► The conceptual design of a pyroprocess demonstration facility was performed. ► The design requirements for the pyroprocess hot cell and equipment were determined. ► The maintenance concept for the pyroprocess hot cell was presented. -- Abstract: The development of an effective management technology of spent fuel is important to enhance environmental friendliness, cost viability and proliferation resistance. In Korea, pyroprocess technology has been considered as a fuel cycle option to solve the spent fuel accumulation problems. PRIDE (PyRoprocess Integrated inactive DEmonstration facility) has been developed from 2007 to 2012 in Korea as a cold test facility to support integrated pyroprocessing and an equipment demonstration, which is essential to verify the pyroprocess technology. As the next stage of PRIDE, the design requirements of an engineering-scale demonstration facility are being developed, and the preliminary conceptual design of the facility is being performed for the future. In this paper, the main design requirements for the engineering-scale pyroprocess demonstration facility were studied in the throughput of 10tHM a year. For the preliminary conceptual design of the facility, the design basis of the pyroprocess hot cell was suggested, and the main equipment, main process area, operation area, maintenance area, and so on were arranged in consideration of the effective operation of the hot cells. Also, the argon system was designed to provide and maintain a proper inert environment for the pyroprocess. The preliminary conceptual design data will be used to review the validity of the engineering-scale pyroprocess demonstration facility that enhances both safety and nonproliferation
Fuel management options to extend the IRIS reactor cycle
International Nuclear Information System (INIS)
Petrovic, B.; Franceschini, F.
2004-01-01
To optimize plant operation, reduce scheduled maintenance outage, and increase capacity factor, IRIS is designed to enable extended cycles of up to four years. However, due to the enrichment licensing limitation (less than 5% enriched uranium oxide) there is a tradeoff between the achievable cycle length and fuel utilization, i.e., the average fuel discharge burnup. The longest individual cycle may be achieved with the single-batch straight burn, but at the expense of a lower burnup. Considering the IRIS basic performance requirements, a cycle length in the range of three to four years is deemed desirable. This paper examines different fuel management options, i.e., the influence of the required cycle length on the corresponding reloading strategy, including a two-batch and a three-batch reloading. A reference two-batch core design has been developed for the first cycle, as well as for the transition cycles leading to equilibrium. Main core performance parameters are evaluated. This core design provides the framework for the safety analyses needed to prepare the IRIS safety evaluations. Alternate designs are also considered.(author)
International Nuclear Information System (INIS)
Xiao, F.; Lilun, Q.; Changsun, S.
1989-01-01
In this paper, thermoeconomic principle is used to study the selection of working fluids and the option of the cycle parameters in the organic Rankine cycle of low temperature waste heat recovery. The parameter ξ, the product of the ratio of waste heat recovery and real cycle thermal efficiency, is suggested as a unified thermodynamic criterion for the selection of the working fluids. The mathematical expressions are developed to determine the optimal boiling temperature and the optimal pin point temperature difference in the heat recovery exchanger by way of thermoeconomic principle
Parameter calibration for synthesizing realistic-looking variability in offline handwriting
Cheng, Wen; Lopresti, Dan
2011-01-01
Motivated by the widely accepted principle that the more training data, the better a recognition system performs, we conducted experiments asking human subjects to do evaluate a mixture of real English handwritten text lines and text lines altered from existing handwriting with various distortion degrees. The idea of generating synthetic handwriting is based on a perturbation method by T. Varga and H. Bunke that distorts an entire text line. There are two purposes of our experiments. First, we want to calibrate distortion parameter settings for Varga and Bunke's perturbation model. Second, we intend to compare the effects of parameter settings on different writing styles: block, cursive and mixed. From the preliminary experimental results, we determined appropriate ranges for parameter amplitude, and found that parameter settings should be altered for different handwriting styles. With the proper parameter settings, it should be possible to generate large amount of training and testing data for building better off-line handwriting recognition systems.
Directory of Open Access Journals (Sweden)
Mitchell Schulte
2009-06-01
Full Text Available The citric acid cycle (CAC is the central pathway of energy transfer for many organisms, and understanding the origin of this pathway may provide insight into the origins of metabolism. In order to assess the thermodynamics of this key pathway for microorganisms that inhabit a wide variety of environments, especially those found in high temperature environments, we have calculated the properties and parameters for the revised Helgeson-Kirkham-Flowers equation of state for the major components of the CAC. While a significant amount of data is not available for many of the constituents of this fundamental pathway, methods exist that allow estimation of these missing data.
Performance assessment of simple and modified cycle turboshaft gas turbines
Directory of Open Access Journals (Sweden)
Barinyima Nkoi
2013-06-01
Full Text Available This paper focuses on investigations encompassing comparative assessment of gas turbine cycle options. More specifically, investigation was carried out of technical performance of turboshaft engine cycles based on existing simple cycle (SC and its projected modified cycles for civil helicopter application. Technically, thermal efficiency, specific fuel consumption, and power output are of paramount importance to the overall performance of gas turbine engines. In course of carrying out this research, turbomatch software established at Cranfield University based on gas turbine theory was applied to conduct simulation of a simple cycle (baseline two-spool helicopter turboshaft engine model with free power turbine. Similarly, some modified gas turbine cycle configurations incorporating unconventional components, such as engine cycle with low pressure compressor (LPC zero-staged, recuperated engine cycle, and intercooled/recuperated (ICR engine cycle, were also simulated. In doing so, design point (DP and off-design point (OD performances of the engine models were established. The percentage changes in performance parameters of the modified cycle engines over the simple cycle were evaluated and it was found that to a large extent, the modified engine cycles with unconventional components exhibit better performances in terms of thermal efficiency and specific fuel consumption than the traditional simple cycle engine. This research made use of public domain open source references.
International Nuclear Information System (INIS)
Granovskii, Mikhail; Dincer, Ibrahim; Rosen, Marc A.; Pioro, Igor
2008-01-01
Increases in the power generation efficiency of nuclear power plants (NPPs) are mainly limited by the permissible temperatures in nuclear reactors and the corresponding temperatures and pressures of the coolants in reactors. Coolant parameters are limited by the corrosion rates of materials and nuclear-reactor safety constraints. The advanced construction materials for the next generation of CANDU reactors, which employ supercritical water (SCW) as a coolant and heat carrier, permit improved 'steam' parameters (outlet temperatures up to 625degC and pressures of about 25 MPa). An increase in the temperature of steam allows it to be utilized in thermochemical water splitting cycles to produce hydrogen. These methods are considered by many to be among the most efficient ways to produce hydrogen from water and to have advantages over traditional low-temperature water electrolysis. However, even lower temperature water splitting cycles (Cu-Cl, UT-3, etc.) require an intensive heat supply at temperatures higher than 550-600degC. A sufficient increase in the heat transfer from the nuclear reactor to a thermochemical water splitting cycle, without jeopardizing nuclear reactor safety, might be effectively achieved by application of a heat pump, which increases the temperature of the heat supplied by virtue of a cyclic process driven by mechanical or electrical work. Here, a high-temperature chemical heat pump, which employs the reversible catalytic methane conversion reaction, is proposed. The reaction shift from exothermic to endothermic and back is achieved by a change of the steam concentration in the reaction mixture. This heat pump, coupled with the second steam cycle of a SCW nuclear power generation plant on one side and a thermochemical water splitting cycle on the other, increases the temperature of the 'nuclear' heat and, consequently, the intensity of heat transfer into the water splitting cycle. A comparative preliminary thermodynamic analysis is conducted of
High speed acquisition of multi-parameter data using a Macintosh II CX
International Nuclear Information System (INIS)
Berno, A.; Vogel, J.S.; Caffee, M.
1990-08-01
Accelerator mass spectrometry systems based on >3MV tandem accelerators often use multi-anode ionization detectors and/or time-of-flight detectors to identify individual isotopes through multi-parameter analysis. A Macintosh llcx has been programmed to collect AMS data from a CAMAC-implemented analyzer and to display the histogrammed individual parameters and a double-parameter array. The computer-CAMAC connection is through a Nu-Bus to CAMAC dataway interface which allows direct addressing to all functions and locations in the crate. The asynchronous data from counting the rare isotope is sorted into a CAMAC memory module by a list sequence controller. Isotope switching is controlled by a one-cycle timing generator. A rate-dependent amount of time is used to transfer the data from the memory module at the end of each timing cycle. The present configuration uses 10 to 75 ms for rates of 500--10000 cps. Parameter analysis occurs during the rest of the 520 ms data collection cycle. Completed measurements of the isotope concentrations of each sample are written to files which are compatible with standard Macintosh databases or other processing programs. The system is inexpensive and operates at speeds comparable to those obtainable using larger computers
A parameter tree approach to estimating system sensitivities to parameter sets
International Nuclear Information System (INIS)
Jarzemba, M.S.; Sagar, B.
2000-01-01
A post-processing technique for determining relative system sensitivity to groups of parameters and system components is presented. It is assumed that an appropriate parametric model is used to simulate system behavior using Monte Carlo techniques and that a set of realizations of system output(s) is available. The objective of our technique is to analyze the input vectors and the corresponding output vectors (that is, post-process the results) to estimate the relative sensitivity of the output to input parameters (taken singly and as a group) and thereby rank them. This technique is different from the design of experimental techniques in that a partitioning of the parameter space is not required before the simulation. A tree structure (which looks similar to an event tree) is developed to better explain the technique. Each limb of the tree represents a particular combination of parameters or a combination of system components. For convenience and to distinguish it from the event tree, we call it the parameter tree. To construct the parameter tree, the samples of input parameter values are treated as either a '+' or a '-' based on whether or not the sampled parameter value is greater than or less than a specified branching criterion (e.g., mean, median, percentile of the population). The corresponding system outputs are also segregated into similar bins. Partitioning the first parameter into a '+' or a '-' bin creates the first level of the tree containing two branches. At the next level, realizations associated with each first-level branch are further partitioned into two bins using the branching criteria on the second parameter and so on until the tree is fully populated. Relative sensitivities are then inferred from the number of samples associated with each branch of the tree. The parameter tree approach is illustrated by applying it to a number of preliminary simulations of the proposed high-level radioactive waste repository at Yucca Mountain, NV. Using a
Thermal study of bare tips with various system parameters and incision sizes.
Osher, Robert H; Injev, Valentine P
2006-05-01
To identify major and minor surgeon-controlled parameters that affect incision temperature when performing microincision lens removal using the Alcon Infiniti Vision System. In vitro research and development laboratory, Alcon Research, Irvine, California, USA. Phacoemulsification was performed in eye-bank cadaver eyes and the following parameters evaluated: incision, duty cycle, ultrasound (US) power, aspiration flow rate (AFR), vacuum, pulse, bottle height and balanced salt solution temperature, and tip design/size. Each parameter was varied while the others remained constant. The resulting temperature of the incision and US tip was measured using a thermal camera. Major contributors to elevated incision temperature included incision size, US power, duty cycle, AFR, vacuum setting, tip design, and presence of an ophthalmic viscosurgical device (OVD). Minor contributors included pulse frequency, bottle height, and temperature of the infusate. Microincision lens removal can be performed at safe temperatures with the knowledgeable selection of surgeon-controlled parameters.
Impedances of nickel electrodes cycled in various KOH concentrations
Reid, Margaret A.; Loyselle, Patricia L.
1991-01-01
Recent tests at Hughes have shown that Ni/H2 cells cycled in 26 percent KOH have much longer lives than those cycled in other concentrations. As part of an ongoing program to try to correlate the impedances of nickel electrodes with their life and performance, impedances were measured of a number of electrodes from these tests that had been cycled in concentrations from 21 to 36 percent KOH. These had ranged from about 1000 to 40,000 cycles. After cycling ten times to reduce possible changes due to storage, impedances were measured at five voltages corresponding to low states of charge. The results were analyzed using a standard circuit model including Warburg impedance term. Lower kinetic resistances and Warburg slopes were found for several electrodes which had been cycled in 26 percent KOH even though they had been cycled for a much longer time than the others. Interpretation of the data is complicated by the fact that the cycle lives, storage times, and failure mechanisms varied. Several other circuit models have also been examined, but the best correlations with life were found with parameters obtained from the simple model.
Heat recovery and seed recovery development project: preliminary design report (PDR)
Energy Technology Data Exchange (ETDEWEB)
Arkett, A. H.; Alexander, K. C.; Bolek, A. D.; Blackman, B. K.; Kurrle, P. E.; Tram, S. V.; Warren, A. M.; Ziobrowski, A. J.
1981-06-01
The preliminary design and performance characteristics are described of the 20 MWt heat recovery and seed recovery (HRSR) system to be fabricated, installed, and evaluated to provide a technological basis for the design of commercial size HRSR systems for coal-fired open-cycle MHD power plants. The system description and heat and material balances, equipment description and functional requirements, controls, interfacing systems, and operation and maintenance are detailed. Appendices include: (1) recommended environmental requirements for compliance with federal and state of Tennessee regulations, (2) channel and diffuser simulator, (3) equipment arrangement drawings, and (4) channel and diffuser simulator barrel drawings. (WHK)
Sensitivity of nuclear fuel-cycle cost to uncertainties in nuclear data. Final report
International Nuclear Information System (INIS)
Becker, M.; Harris, D.R.
1980-11-01
An improved capability for assessing the economic implications of uncertainties in nuclear data and methods on the power reactor fuel cycle was developed. This capability is applied to the sensitivity analysis of fuel-cycle cost with respect to changes in nuclear data and related computational methods. Broad group sensitivities for both a typical BWR and a PWR are determined under the assumption of a throwaway fuel cycle as well as for a scenario under which reprocessing is allowed. Particularly large dollar implications are found for the thermal and resonance cross sections of fissile and fertile materials. Sensitivities for the throwaway case are found to be significantly larger than for the recycle case. Constrained sensitivities obtained for cases in which information from critical experiments or other benchmarks is used in the design calculation to adjust a parameter such as anti ν are compared with unconstrained sensitivities. Sensitivities of various alternate fuel cycles were examined. These included the extended-burnup (18-month) LWR cycle, the mixed-oxide (plutonium) cycle, uranium-thorium and denatured uranium-thorium cycles, as well as CANDU-type reactor cycles. The importance of the thermal capture and fission cross sections of 239 Pu is shown to be very large in all cases. Detailed, energy dependent sensitivity profiles are provided for the thermal range (below 1.855 eV). Finally, sensitivity coefficients are combined with data uncertainties to determine the impact of such uncertainties on fuel-cycle cost parameters
Engine cycle design considerations for nuclear thermal propulsion systems
International Nuclear Information System (INIS)
Pelaccio, D.G.; Scheil, C.M.; Collins, J.T.
1993-01-01
A top-level study was performed which addresses nuclear thermal propulsion system engine cycle options and their applicability to support future Space Exploration Initiative manned lunar and Mars missions. Technical and development issues associated with expander, gas generator, and bleed cycle near-term, solid core nuclear thermal propulsion engines are identified and examined. In addition to performance and weight the influence of the engine cycle type on key design selection parameters such as design complexity, reliability, development time, and cost are discussed. Representative engine designs are presented and compared. Their applicability and performance impact on typical near-term lunar and Mars missions are shown
Multiaxial low cycle fatigue life under non-proportional loading
International Nuclear Information System (INIS)
Itoh, Takamoto; Sakane, Masao; Ohsuga, Kazuki
2013-01-01
A simple and clear method of evaluating stress and strain ranges under non-proportional multiaxial loading where principal directions of stress and strain are changed during a cycle is needed for assessing multiaxial fatigue. This paper proposes a simple method of determining the principal stress and strain ranges and the severity of non-proportional loading with defining the rotation angles of the maximum principal stress and strain in a three dimensional stress and strain space. This study also discusses properties of multiaxial low cycle fatigue lives for various materials fatigued under non-proportional loadings and shows an applicability of a parameter proposed by author for multiaxial low cycle fatigue life evaluation
Guidelines for evaluation of the environmental expense in the nuclear fuel cycle
International Nuclear Information System (INIS)
Komatsu, Cintia Nagako
2008-01-01
The main objective of this research is to establish guidelines to fit the environment account in the nuclear fuel cycle, using as study of case the uranium hexafluoride production unit of Centro Tecnologico da Marinha in Sao Paulo. The environment accounting, branch of the accounting science, supply a source of tools capable to measure the protection efforts, the nature preservation, the environment monitoring and the recovering during all the conversion phase (since the uranium concentrated, the yellow cake, up to the Uranium hexafluoride production). It was performed several researches, visits to the Centre, databank creation, interviews and extensive consulting to the preliminary safety report, in order to obtain the percentage of the total expenses related to environment protection in regarding to the total amount invested in the unit. It was also evaluated the total preserved green area making possible a preliminary environment accounting balance. (author)
International Nuclear Information System (INIS)
Hattemer-Frey, H.A.; Krieger, G.R.; Lau, V.
1994-01-01
In the absence of site-specific data, the concentration of metals in plants is typically estimated by multiplying the total concentration of metal in soil by a metal-specific soil-to-root bioconcentration factor (BCF). However, this approach does not account for various soil properties, such as pH, organic matter content, and cation exchange capacity, that are known to influence root uptake of some metals. For risk assessment purposes, a simple, predictive method for estimating root uptake of metals that is based on site-specific soil and crop data is needed so that the importance of the produce ingestion pathway and subsequent influence on human exposure can be quantitatively assessed. An easy-to-use method is necessary since collecting site-specific data on the concentration of metals in home-grown produce is often time-consuming and costly. Ideally, it should be possible to develop a statistically-reliable relationship between plant and soil metals levels that includes appropriate weighing factors for various soil properties. Multiple linear regression analyses were used to develop simple, predictive models for estimating the concentration of metals in plants via root uptake using site-specific soil data. This paper presents preliminary predictive equations for estimating root uptake of arsenic, cadmium, copper, and zinc in fruiting, root, and all vegetables combined (i.e., fruiting and root crop data were combined). Results show that by using data on additional soil parameters (other than relying solely on the concentration of metals in soil), the concentration of metals in fruiting and root vegetables can be more confidently predicted
Relationships of Stroke Patients’ Gait Parameters with Fear of Falling
Park, Jin; Yoo, Ingyu
2014-01-01
[Purpose] The purpose of this study was to assess the correlation of gait parameters with fear of falling in stroke survivors. [Subjects] In total, 12 patients with stroke participated. [Methods] The subjects performed on a Biodex Gait Trainer 2 for 5 min to evaluate characteristic gait parameters. The kinematic gait parameters measured were gait speed, step cycle, step length, and time on each foot (step symmetry). All the subjects also completed a fall anxiety survey. [Results] Correlations...
Potential benefits of saturation cycle with two-phase refrigerant injection
International Nuclear Information System (INIS)
Lee, Hoseong; Hwang, Yunho; Radermacher, Reinhard; Chun, Ho-Hwan
2013-01-01
In this paper, a saturation cycle is proposed to enhance a vapor compression cycle performance by reducing thermodynamic losses associated with single phase gas compression and isenthalpic expansion. In order to approach the saturation cycle, a two-phase refrigerant injection technique is applied to the multi-stage cycle. This multi-stage cycle with different options is modeled, and its performance is evaluated under ASHRAE standard operating conditions for air conditioning systems. Moreover, the two-phase refrigerant injection cycle is compared with the typical vapor injection cycle which is utilizing the internal heat exchanger or the flash tank. Low GWP refrigerants are applied to this two-phase refrigerant injection cycle. In terms of the COP and its improvement, R123 has a higher potential than any other refrigerants in the multi-stage cycle. Lastly, practical ideas realizing the saturation cycle are discussed such as multi-stage phase separator, phase separator with helical structure inside, and injection location of the compressor. -- Highlights: • A saturation cycle is proposed to enhance the vapor compression cycle performance. • Two-phase refrigerant injection technique is applied to the multi-stage cycle. • Modeling results of the proposed cycle show the significant performance improvement. • Low GWP refrigerants are applied and R123 shows the highest performance. • New parameters, α and ε, are used to show the potential of the saturation cycle
Study on fission blanket fuel cycling of a fusion-fission hybrid energy generation system
International Nuclear Information System (INIS)
Zhou, Z.; Yang, Y.; Xu, H.
2011-01-01
This paper presents a preliminary study on neutron physics characteristics of a light water cooled fission blanket for a new type subcritical fusion-fission hybrid reactor aiming at electric power generation with low technical limits of fission fuel. The major objective is to study the fission fuel cycling performance in the blanket, which may possess significant impacts on the feasibility of the new concept of fusion-fission hybrid reactor with a high energy gain (M) and tritium breeding ratio (TBR). The COUPLE2 code developed by the Institute of Nuclear and New Energy Technology of Tsinghua University is employed to simulate the neutronic behaviour in the blanket. COUPLE2 combines the particle transport code MCNPX with the fuel depletion code ORIGEN2. The code calculation results show that soft neutron spectrum can yield M > 20 while maintaining TBR >1.15 and the conversion ratio of fissile materials CR > 1 in a reasonably long refuelling cycle (>five years). The preliminary results also indicate that it is rather promising to design a high-performance light water cooled fission blanket of fusion-fission hybrid reactor for electric power generation by directly loading natural or depleted uranium if an ITER-scale tokamak fusion neutron source is achievable.
International Nuclear Information System (INIS)
Ouzounian, G.H.; Devezeaux de Lavergne, J.G.; Devin, P.; Lioure, A.; Mouney, H.; Le Boulch, D.
2001-01-01
Research programs conducted in France in the framework of the 1991 act offer various options for management of the back- end of the fuel cycle. Proposals to be debated in 2006 will rely not only on broad scientific and technical knowledge, but also on the compilation and integration of results, with syntheses and analyses intended to highlight the advantages and the limitations of each of the waste management paths. This presentation introduces a methodology derived from the life cycle analysis as well as some preliminary results. (author)
Milingo, Jackie; Saar, Steven; Marschall, Laurence
2018-01-01
We present a 25 yr compilation of V-band differential photometry for the Pleiades K dwarf HII 1883 (V660 Tau). HII 1883 has a rotational period of ~ 0.24 d and displays significant rotational modulation due to non-uniform surface brightness or "starspots". Preliminary work yields a cycle period of ~ 9 yrs and rotational shear (ΔP_rot/) considerably less than solar. HII 1883 is one of the fastest rotating single stars with a known cycle. With additional data available we compare newly determined P_cyc and ΔP_rot/ values with those of other stars, putting HII 1883 into the broader context of dynamo properties in single cool dwarfs.
Parametric analysis for a new combined power and ejector-absorption refrigeration cycle
International Nuclear Information System (INIS)
Wang Jiangfeng; Dai Yiping; Zhang Taiyong; Ma Shaolin
2009-01-01
A new combined power and ejector-absorption refrigeration cycle is proposed, which combines the Rankine cycle and the ejector-absorption refrigeration cycle, and could produce both power output and refrigeration output simultaneously. This combined cycle, which originates from the cycle proposed by authors previously, introduces an ejector between the rectifier and the condenser, and provides a performance improvement without greatly increasing the complexity of the system. A parametric analysis is conducted to evaluate the effects of the key thermodynamic parameters on the cycle performance. It is shown that heat source temperature, condenser temperature, evaporator temperature, turbine inlet pressure, turbine inlet temperature, and basic solution ammonia concentration have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. It is evident that the ejector can improve the performance of the combined cycle proposed by authors previously.
Directory of Open Access Journals (Sweden)
Basabdatta Sen Bhattacharya
2014-05-01
Full Text Available We present a preliminary study of a thalamo-cortico-thalamic (TCT implementation on SpiNNaker (Spiking Neural Network architecture, a brain inspired hardware platform designed to incorporate the inherent biological properties of parallelism, fault tolerance and energy efficiency. These attributes make SpiNNaker an ideal platform for simulating biologically plausible computational models. Our focus in this work is to design a TCT framework that can be simulated on SpiNNaker to mimic dynamical behaviour similar to Electroencephalogram (EEG time and power-spectra signatures in sleep-wake transition. The scale of the model is minimised for simplicity in this proof-of-concept study; thus the total number of spiking neurons is approximately 1000 and represents a `mini-column' of the thalamocortical tissue. All data on model structure, synaptic layout and parameters is inspired from previous studies and abstracted at a level that is appropriate to the aims of the current study as well as computationally suitable for model simulation on a small 4-chip SpiNNaker system. The initial results from selective deletion of synaptic connectivity parameters in the model show similarity with EEG time series characteristics of sleep and wakefulness. These observations provide a positive perspective and a basis for future implementation of a very large scale biologically plausible model of thalamo-cortico-thalamic interactivity---the essential brain circuit that regulates the biological sleep-wake cycle and associated EEG rhythms.
International Nuclear Information System (INIS)
Ghezzi, Luan; Da Costa, Luiz N.; Maia, Marcio A. G.; Ogando, Ricardo L. C.; Dutra-Ferreira, Letícia; Lorenzo-Oliveira, Diego; Porto de Mello, Gustavo F.; Santiago, Basílio X.; De Lee, Nathan; Lee, Brian L.; Ge, Jian; Wisniewski, John P.; González Hernández, Jonay I.; Stassun, Keivan G.; Cargile, Phillip; Pepper, Joshua; Fleming, Scott W.; Schneider, Donald P.; Mahadevan, Suvrath; Wang, Ji
2014-01-01
Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff , metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. Therefore, most surveys employ spectral synthesis, which is a powerful technique, but relies heavily on the completeness and accuracy of atomic line databases and can yield possibly correlated atmospheric parameters. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R ∼ 12,000). To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. The calibrations were derived using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra, permitting the low-resolution equivalent widths to be directly related to the stellar parameters. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters derived from the high-resolution spectra and spectroscopic analysis based on the excitation and ionization equilibria method. Our approach was able to recover the parameters within 80 K for T eff , 0.05 dex for [Fe/H], and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analyses. An additional test
International Nuclear Information System (INIS)
Dai Yiping; Wang Jiangfeng; Gao Lin
2009-01-01
Organic Rankine cycles for low grade waste heat recovery are described with different working fluids. The effects of the thermodynamic parameters on the ORC performance are examined, and the thermodynamic parameters of the ORC for each working fluid are optimized with exergy efficiency as an objective function by means of the genetic algorithm. The optimum performance of cycles with different working fluids was compared and analyzed under the same waste heat condition. The results show that the cycles with organic working fluids are much better than the cycle with water in converting low grade waste heat to useful work. The cycle with R236EA has the highest exergy efficiency, and adding an internal heat exchanger into the ORC system could not improve the performance under the given waste heat condition. In addition, for the working fluids with non-positive saturation vapor curve slope, the cycle has the best performance property with saturated vapor at the turbine inlet
International Nuclear Information System (INIS)
Tort, V.; Lochard, J.; Schneider, T.; Sugier, A.
1997-12-01
This report is an attempt to contribute to the complex issue of the decision-making in the field of radioactive waste management. Because of the complex and multidimensional nature of the distant future consequences of waste management options, their analysis implies the taking into considerations of various aggregated indicators which depend on the elapse of time during which the radionuclides remain in the environment and their local, regional or world-wide dispersion. This report is a preliminary work sponsored by IPSN mainly focused on the risk transfer dimension, inherent to waste disposal management. Its objective is to illustrate, using the French nuclear fuel cycle context, the relative impact of some simple waste management options, outlining particularly the issue of inter-generation risk transfer. Even though the selected six radionuclides are the most important, a complete assessment should include all the radionuclides contained in the waste, what is particularly important in case of underground waste disposal were both normal evolution scenarios and intrusion must be considered. The extreme alternatives, i.e. the total disposal or total release of the radionuclides are analyzed but realistic are the intermediate options, which should be thoroughly examined from the technical point of view. The analysis of intermediate management options could give an estimation of the most appropriate solution in an ALARA perspective
International Nuclear Information System (INIS)
Lopes, F; Barbosa, S M; Silva, H G; Bárias, S
2015-01-01
The atmospheric electric field near the Earth's surface is dominated by atmospheric pollutants and natural radioactivity, with the latter directly linked to radon ( 222 Rn) gas. For a better comprehension on the temporal variability of both the atmospheric electric field and the radon concentration and its relation with local atmospheric variables, simultaneous measurements of soil-emitted gamma radiation and potential gradient (defined from the vertical component of the atmospheric electric field) were taken every minute, along with local meteorological parameters (e.g., temperature, atmospheric pressure, relative humidity and daily solar radiation). The study region is Amieira, part of the Alqueva lake in Alentejo Portugal, where an interdisciplinary meteorological campaign, ALEX2014, took place from June to August 2014. Soil gamma radiation is more sensitive to small concentrations of radon as compared with alpha particles measurements, for that reason it is more suited for sites with low radon levels, as expected in this case. Preliminary results are presented here: statistical and spectral analysis show that i) the potential gradient has a stronger daily cycle as compared with the gamma radiation, ii) most of the energy of the gamma signal is concentrated in the low frequencies (close to 0), contrary to the potential gradient that has most of the energy in frequency 1 (daily cycle) and iii) a short-term relation between gamma radiation and the potential gradient has not been found. Future work and plans are also discussed. (paper)
International Nuclear Information System (INIS)
Ciornei, R.
1991-01-01
To provide severe safety rules governing the operation of nuclear power plants, reinforced and concrete elements and structures should preserve the quality and time-constant parameters throughout the life-time of the buildings. Some important design parameters are concrete strength and elasticity modulus. Preliminary research on concrete specimens made in laboratory whose strength and static and dynamic elasticity modulus have been determined after an ageing test, has aimed at nuclear power design and building. (author)
The inherent complexity in nonlinear business cycle model in resonance
International Nuclear Information System (INIS)
Ma Junhai; Sun Tao; Liu Lixia
2008-01-01
Based on Abraham C.-L. Chian's research, we applied nonlinear dynamic system theory to study the first-order and second-order approximate solutions to one category of the nonlinear business cycle model in resonance condition. We have also analyzed the relation between amplitude and phase of second-order approximate solutions as well as the relation between outer excitements' amplitude, frequency approximate solutions, and system bifurcation parameters. Then we studied the system quasi-periodical solutions, annulus periodical solutions and the path leading to system bifurcation and chaotic state with different parameter combinations. Finally, we conducted some numerical simulations for various complicated circumstances. Therefore this research will lay solid foundation for detecting the complexity of business cycles and systems in the future
Influence of driving cycles on Euro 3 scooter emissions and fuel consumption
International Nuclear Information System (INIS)
Prati, Maria V.; Zamboni, Giorgio; Costagliola, Maria A.; Meccariello, Giovanni; Carraro, Chiara; Capobianco, Massimo
2011-01-01
Highlights: → Fuel consumption and emissions of Euro 3 scooters defined on different driving cycles. → Comparison of standard, real world driving cycles and measured urban speed patterns. → Statistical analysis of kinematic parameters to group driving cycle in clusters. → Clusters can explain pollutant and fuel consumption behaviour in hot conditions. → Cold start mixture enrichment strategy has a major influence on extra-emissions. - Abstract: Regulated pollutant emissions and fuel consumption were characterized at the exhaust of two Euro 3 4-stroke medium-size motorcycles during the execution of both standard and real world driving cycles. A principal component analysis was carried out to group in a cluster the driving cycles with similar kinematic parameters. Hot start results, analysed according to this cluster grouping, show that the main differences are explained by overall mean speed and high positive acceleration of driving cycles. Lower mean speeds produce higher CO 2 emission factors, while the influence on CO and HC is more complex. NO X are not significantly affected by the driving pattern. Inside the same cluster, the whole duration of the acceleration phases could discriminate emission behaviour. In-depth analysis of cold start results was conducted in order to assess the influence of the driving cycle and vehicle characteristics on cold start duration. Cold start extra emissions are more influenced by the duration of the enrichment phase than by the catalyst light-off. The larger number of accelerations occurring during real world driving cycles produces higher variability of air fuel ratio and hence higher cold start extra emissions.
Energy Technology Data Exchange (ETDEWEB)
Sharma, Nandini, E-mail: nandini-sharma@merck.com; Toney, Jeffrey H.; Fitzgerald, Paula M. D.
2005-02-01
Crystallization and preliminary X-ray analysis of the CphA metallo-β-lactamase from A. hydrophilia are described. The crystals belonged to space group P2{sub 1}2{sub 1}2, with unit-cell parameters a = 40.75, b = 42.05, c = 128.88 Å, and diffract to 1.8 Å.
A study of implementing In-Cycle-Shuffle strategy to a decommissioning boiling water reactor
International Nuclear Information System (INIS)
Chen, Chung-Yuan; Tung, Wu-Hsiung; Yaur, Shyun-Jung
2017-01-01
Highlights: • A loading pattern strategy ICS (In-Cycle-Shuffle) was implemented to the last cycle of the boiling water reactor. • The best power sharing distribution and ICS timing was found. • A new parameter “Burnup sharing” is presented to evaluate ICS strategy. - Abstract: In this paper, a loading pattern strategy In-Cycle-Shuffle (ICS) is implemented to the last cycle of the boiling water reactor (BWR) before decommissioning to save the fuel cycle cost. This method needs a core shutdown during the operation of a cycle to change the loading pattern to gain more reactivity. The reactivity model is used to model the ICS strategy in order to find out the best ICS timing and the optimum power sharing distribution before ICS and after ICS. Several parameters of reactivity model are modified and the effect of burnable poison, gadolinium (Gd), is considered in this research. Three cases are presented and it is found that the best ICS timing is at about two-thirds of total cycle length no matter the poisoning effect of Gd is considered or not. According to the optimum power sharing distribution result, it is suggested to decrease the once burnt power and increase the thrice burnt fuel power as much as possible before ICS. After ICS, it is suggested to increase the positive reactivity fuel power and decrease the thrice burnt fuel power as much as possible. A new parameter “Burnup sharing” is presented to evaluate the special case whose EOC power weighting factor and the burnup accumulation factor in the reactivity model are quite different.
A study of implementing In-Cycle-Shuffle strategy to a decommissioning boiling water reactor
Energy Technology Data Exchange (ETDEWEB)
Chen, Chung-Yuan, E-mail: tuckjason@iner.gov.tw; Tung, Wu-Hsiung; Yaur, Shyun-Jung
2017-06-15
Highlights: • A loading pattern strategy ICS (In-Cycle-Shuffle) was implemented to the last cycle of the boiling water reactor. • The best power sharing distribution and ICS timing was found. • A new parameter “Burnup sharing” is presented to evaluate ICS strategy. - Abstract: In this paper, a loading pattern strategy In-Cycle-Shuffle (ICS) is implemented to the last cycle of the boiling water reactor (BWR) before decommissioning to save the fuel cycle cost. This method needs a core shutdown during the operation of a cycle to change the loading pattern to gain more reactivity. The reactivity model is used to model the ICS strategy in order to find out the best ICS timing and the optimum power sharing distribution before ICS and after ICS. Several parameters of reactivity model are modified and the effect of burnable poison, gadolinium (Gd), is considered in this research. Three cases are presented and it is found that the best ICS timing is at about two-thirds of total cycle length no matter the poisoning effect of Gd is considered or not. According to the optimum power sharing distribution result, it is suggested to decrease the once burnt power and increase the thrice burnt fuel power as much as possible before ICS. After ICS, it is suggested to increase the positive reactivity fuel power and decrease the thrice burnt fuel power as much as possible. A new parameter “Burnup sharing” is presented to evaluate the special case whose EOC power weighting factor and the burnup accumulation factor in the reactivity model are quite different.
International Nuclear Information System (INIS)
Numasawa, T.; Hashimoto, T.
1981-01-01
The final working cycle in the magnetic refrigeration largely depends on the heat transfer coefficient β in the system, the parameter γ of the heat inflow from the outer system to this cycle and the period tau of the cycle. Therefore, so as to make clear this dependence, the time variation of the Brayton cycle with β, γ and tau has been investigated. In the present paper the transitional process of this cycle and the dependence of the final cooling temperature of the heat load on β, γ and tau have all been shown. (orig.)
Web-based automation of green building rating index and life cycle cost analysis
Shahzaib Khan, Jam; Zakaria, Rozana; Aminuddin, Eeydzah; IzieAdiana Abidin, Nur; Sahamir, Shaza Rina; Ahmad, Rosli; Nafis Abas, Darul
2018-04-01
Sudden decline in financial markets and economic meltdown has slow down adaptation and lowered interest of investors towards green certified buildings due to their higher initial costs. Similarly, it is essential to fetch investor’s attention towards more development of green buildings through automated tools for the construction projects. Though, historical dearth is found on the automation of green building rating tools that brings up an essential gap to develop an automated analog computerized programming tool. This paper present a proposed research aim to develop an integrated web-based automated analog computerized programming that applies green building rating assessment tool, green technology and life cycle cost analysis. It also emphasizes to identify variables of MyCrest and LCC to be integrated and developed in a framework then transformed into automated analog computerized programming. A mix methodology of qualitative and quantitative survey and its development portray the planned to carry MyCrest-LCC integration to an automated level. In this study, the preliminary literature review enriches better understanding of Green Building Rating Tools (GBRT) integration to LCC. The outcome of this research is a pave way for future researchers to integrate other efficient tool and parameters that contributes towards green buildings and future agendas.
Fuel and fuel cycles with high burnup for WWER reactors
International Nuclear Information System (INIS)
Chernushev, V.; Sokolov, F.
2002-01-01
The paper discusses the status and trends in development of nuclear fuel and fuel cycles for WWER reactors. Parameters and main stages of implementation of new fuel cycles will be presented. At present, these new fuel cycles are offered to NPPs. Development of new fuel and fuel cycles based on the following principles: profiling fuel enrichment in a cross section of fuel assemblies; increase of average fuel enrichment in fuel assemblies; use of refuelling schemes with lower neutron leakage ('in-in-out'); use of integrated fuel gadolinium-based burnable absorber (for a five-year fuel cycle); increase of fuel burnup in fuel assemblies; improving the neutron balance by using structural materials with low neutron absorption; use of zirconium alloy claddings which are highly resistant to irradiation and corrosion. The paper also presents the results of fuel operation. (author)
Hyperon radiative decays, the α parameter of Σ+ → pγ first results from Fermilab E761
International Nuclear Information System (INIS)
Foucher, M.
1991-05-01
A high statistics study of the hyperon radiative decay, Σ + → pγ, has been performed in the Proton Center charged hyperon beam at Fermilab. A preliminary result for the α parameter for Σ + → pγ is presented. We find the α parameter to be -0.69 ± (0.11 statistical) ±(0.11 ± 0.11 systematic). 4 refs., 4 figs
LIFE CYCLE ASSESSMENT IN HEALTHCARE SYSTEM OPTIMIZATION. INTRODUCTION
Directory of Open Access Journals (Sweden)
V. Sarancha
2015-03-01
Full Text Available Article describes the life cycle assessment method and introduces opportunities for method performance in healthcare system settings. LSA draws attention to careful use of resources, environmental, human and social responsibility. Modelling of environmental and technological inputs allows optimizing performance of the system. Various factors and parameters that may influence effectiveness of different sectors in healthcare system are detected. Performance optimization of detected parameters could lead to better system functioning, higher patient safety, economic sustainability and reduce resources consumption.
International Nuclear Information System (INIS)
Kim, Kyoung Hoon; Kim, Kyung Chun
2014-01-01
Thermodynamic analysis of a combined cycle using a low grade heat source and LNG cold energy was carried out. The combined cycle consisted of an ammonia–water Rankine cycle with and without regeneration and a LNG Rankine cycle. A parametric study was conducted to examine the effects of the key parameters, such as ammonia mass fraction, turbine inlet pressure, condensation temperature. The effects of the ammonia mass fraction on the temperature distributions of the hot and cold streams in heat exchangers were also investigated. The characteristic diagram of the exergy efficiency and heat transfer capability was proposed to consider the system performance and expenditure of the heat exchangers simultaneously. The simulation showed that the system performance is influenced significantly by the parameters with the ammonia mass fraction having largest effect. The net work output of the ammonia–water cycle may have a peak value or increase monotonically with increasing ammonia mass fraction, which depends on turbine inlet pressure or condensation temperature. The exergy efficiency may decrease or increase or have a peak value with turbine inlet pressure depending on the ammonia mass fraction. - Highlights: • Thermodynamic analysis was performed for a combined cycle utilizing LNG cold energy. • Ammonia–water Rankine cycle and LNG Rankine cycle was combined. • A parametric study was conducted to examine the effects of the key parameters. • Characteristics of the exergy efficiency and heat transfer capability were proposed. • The system performance was influenced significantly by the ammonia mass fraction
Ground level enhancement (GLE) energy spectrum parameters model
Qin, G.; Wu, S.
2017-12-01
We study the ground level enhancement (GLE) events in solar cycle 23 with the four energy spectra parameters, the normalization parameter C, low-energy power-law slope γ 1, high-energy power-law slope γ 2, and break energy E0, obtained by Mewaldt et al. 2012 who fit the observations to the double power-law equation. we divide the GLEs into two groups, one with strong acceleration by interplanetary (IP) shocks and another one without strong acceleration according to the condition of solar eruptions. We next fit the four parameters with solar event conditions to get models of the parameters for the two groups of GLEs separately. So that we would establish a model of energy spectrum for GLEs for the future space weather prediction.
Thermodynamic cycle calculations for a pumped gaseous core fission reactor
International Nuclear Information System (INIS)
Kuijper, J.C.; Van Dam, H.
1991-01-01
Finite and 'infinitesimal' thermodynamic cycle calculations have been performed for a 'solid piston' model of a pumped Gaseous Core Fission Reactor with dissociating reactor gas, consisting of Uranium, Carbon and Fluorine ('UCF'). In the finite cycle calculations the influence has been investigated of several parameters on the thermodynamics of the system, especially on the attainable direct (nuclear to electrical) energy conversion efficiency. In order to facilitate the investigation of the influence of dissociation, a model gas, 'Modelium', was developed, which approximates, in a simplified, analytical way, the dissociation behaviour of the 'real' reactor gas. Comparison of the finite cycle calculation results with those of a so-called infinitesimal Otto cycle calculation leads to the conclusion that the conversion efficiency of a finite cycle can be predicted, without actually performing the finite cycle calculation, with reasonable accuracy, from the so-called 'infinitesimal efficiency factor', which is determined only by the thermodynamic properties of the reactor gas used. (author)
Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System
Directory of Open Access Journals (Sweden)
L.P. Rodriguez
2015-08-01
Full Text Available Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR and two Pebble-Bed Accelerator Driven Systems (ADSs was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.
Preliminary analysis for model development of groundwater evolution in Horonobe area
International Nuclear Information System (INIS)
Yoshida, Yasushi; Yui, Mikazu
2003-03-01
The preliminary analysis for model development of groundwater evolution in Horonobe area was performed with data at D-1, HDB-1 and HDB-2 bore hole where hydrogen / oxygen isotope concentration, mineral property in sedimentary rock and physico-chemical parameters (pH, Eh and ionic concentrations) were measured. As a result of analysis for hydrogen and oxygen isotope concentration, saline water in marine sediment was diluted by the mixing with shallow groundwater and diffusion. And as a result of analysis for a concentration of bicarbonate from the difference of pH values measured between in-situ and under air, the estimated in-situ concentration of bicarbonate differs from that measured under air. And minerals which were assumed to be equilibrium with groundwater were selected by thermodynamic calculation. This report presents the results of preliminary analysis for groundwater evolution by using data derived from D-1, HDB-1 and HDB-2 boring research. In order to establish the model which interprets the groundwater evolution as a next step, data which satisfy the representative in-situ property of groundwater chemistry in Horonobe area are needed. Reliable measurements for physico-chemical parameter and property of minerals in sedimentary rock in dominant layer and at the variety of depth are also needed. (author)
Ghezzi, Luan; Dutra-Ferreira, Letícia; Lorenzo-Oliveira, Diego; Porto de Mello, Gustavo F.; Santiago, Basílio X.; De Lee, Nathan; Lee, Brian L.; da Costa, Luiz N.; Maia, Marcio A. G.; Ogando, Ricardo L. C.; Wisniewski, John P.; González Hernández, Jonay I.; Stassun, Keivan G.; Fleming, Scott W.; Schneider, Donald P.; Mahadevan, Suvrath; Cargile, Phillip; Ge, Jian; Pepper, Joshua; Wang, Ji; Paegert, Martin
2014-12-01
Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff, metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. Therefore, most surveys employ spectral synthesis, which is a powerful technique, but relies heavily on the completeness and accuracy of atomic line databases and can yield possibly correlated atmospheric parameters. In this work, we use an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R ~ 12,000). To avoid a time-consuming manual analysis, we have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices, and, through a comparison of those with values calculated with predetermined calibrations, estimate the atmospheric parameters of the stars. The calibrations were derived using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra, permitting the low-resolution equivalent widths to be directly related to the stellar parameters. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters derived from the high-resolution spectra and spectroscopic analysis based on the excitation and ionization equilibria method. Our approach was able to recover the parameters within 80 K for T eff, 0.05 dex for [Fe/H], and 0.15 dex for log g, values that are lower than or equal to the typical external uncertainties found between different high-resolution analyses. An additional test was
Bifurcation diagram of a cubic three-parameter autonomous system
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Lenka Barakova
2005-07-01
Full Text Available In this paper, we study the cubic three-parameter autonomous planar system $$displaylines{ dot x_1 = k_1 + k_2x_1 - x_1^3 - x_2,cr dot x_2 = k_3 x_1 - x_2, }$$ where $k_2, k_3$ are greater than 0. Our goal is to obtain a bifurcation diagram; i.e., to divide the parameter space into regions within which the system has topologically equivalent phase portraits and to describe how these portraits are transformed at the bifurcation boundaries. Results may be applied to the macroeconomical model IS-LM with Kaldor's assumptions. In this model existence of a stable limit cycles has already been studied (Andronov-Hopf bifurcation. We present the whole bifurcation diagram and among others, we prove existence of more difficult bifurcations and existence of unstable cycles.
Ecological optimization for an irreversible magnetic Ericsson refrigeration cycle
International Nuclear Information System (INIS)
Wang Hao; Wu Guo-Xing
2013-01-01
An irreversible Ericsson refrigeration cycle model is established, in which multi-irreversibilities such as finite-rate heat transfer, regenerative loss, heat leakage, and the efficiency of the regenerator are taken into account. Expressions for several important performance parameters, such as the cooling rate, coefficient of performance (COP), power input, exergy output rate, entropy generation rate, and ecological function are derived. The influences of the heat leakage and the time of the regenerative processes on the ecological performance of the refrigerator are analyzed. The optimal regions of the ecological function, cooling rate, and COP are determined and evaluated. Furthermore, some important parameter relations of the refrigerator are revealed and discussed in detail. The results obtained here have general significance and will be helpful in gaining a deep understanding of the magnetic Ericsson refrigeration cycle. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Crystallization and preliminary X-ray diffraction analysis of West Nile virus
International Nuclear Information System (INIS)
Kaufmann, Bärbel; Plevka, Pavel; Kuhn, Richard J.; Rossmann, Michael G.
2010-01-01
Crystals of infectious West Nile virus were obtained and diffracted at best to about 25 Å resolution. Preliminary analysis of the diffraction pattern suggested tight hexagonal packing of the intact virus. West Nile virus, a human pathogen, is closely related to other medically important flaviviruses of global impact such as dengue virus. The infectious virus was purified from cell culture using polyethylene glycol (PEG) precipitation and density-gradient centrifugation. Thin amorphously shaped crystals of the lipid-enveloped virus were grown in quartz capillaries equilibrated by vapor diffusion. Crystal diffraction extended at best to a resolution of about 25 Å using synchrotron radiation. A preliminary analysis of the diffraction images indicated that the crystals had unit-cell parameters a ≃ b ≃ 480 Å, γ = 120°, suggesting a tight hexagonal packing of one virus particle per unit cell
Comparative of fuel cycle cost for light water nuclear power plants
International Nuclear Information System (INIS)
Kocic, A.; Dimitrijevic, Z.
1978-01-01
Starting from ost general fuel cycle scheme for light water reactors this article deals with conceptual differences of BWR, PWR and WWER as well as with the influence of certain phases of fuel cycle on economic parameters of an equivalent 1000 MWe reactor using a computer program CENA /1/ and typical parameters of each reactor type. An analysis of two particular power plants 628 MWe and 440 MWe WWER by means of the same program is given in the second part of this paper taking into account the differences of in-core fuel management. This second approach is especially interesting for the economy of the power plant itself in the period of planning. (author)
Exergy analysis for combined regenerative Brayton and inverse Brayton cycles
Zelong Zhang, Lingen Chen, Fengrui Sun
2012-01-01
This paper presents the study of exergy analysis of combined regenerative Brayton and inverse Brayton cycles. The analytical formulae of exergy loss and exergy efficiency are derived. The largest exergy loss location is determined. By taking the maximum exergy efficiency as the objective, the choice of bottom cycle pressure ratio is optimized by detailed numerical examples, and the corresponding optimal exergy efficiency is obtained. The influences of various parameters on the exergy efficien...
A preliminary study of the tropical water cycle and its sensitivity to surface warming
Lau, K. M.; Sui, C. H.; Tao, W. K.
1993-01-01
The Goddard Cumulus Ensemble Model (GCEM) has been used to demonstrate that cumulus-scale dynamics and microphysics play a major role in determining the vertical distribution of water vapor and clouds in the tropical atmosphere. The GCEM is described and is the basic structure of cumulus convection. The long-term equilibrium response to tropical convection to surface warming is examined. A picture of the water cycle within tropical cumulus clusters is developed.
Laser Theory for Optomechanics: Limit Cycles in the Quantum Regime
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Niels Lörch
2014-01-01
Full Text Available Optomechanical systems can exhibit self-sustained limit cycles where the quantum state of the mechanical resonator possesses nonclassical characteristics such as a strongly negative Wigner density, as was shown recently in a numerical study by Qian et al. [Phys. Rev. Lett. 109, 253601 (2012]. Here, we derive a Fokker-Planck equation describing mechanical limit cycles in the quantum regime that correctly reproduces the numerically observed nonclassical features. The derivation starts from the standard optomechanical master equation and is based on techniques borrowed from the laser theory due to Haake and Lewenstein. We compare our analytical model with numerical solutions of the master equation based on Monte Carlo simulations and find very good agreement over a wide and so far unexplored regime of system parameters. As one main conclusion, we predict negative Wigner functions to be observable even for surprisingly classical parameters, i.e., outside the single-photon strong-coupling regime, for strong cavity drive and rather large limit-cycle amplitudes. The approach taken here provides a natural starting point for further studies of quantum effects in optomechanics.
International Nuclear Information System (INIS)
Vazquez Ramio, H; Regulo, C; Mathur, S; GarcIa, R A
2011-01-01
CoRoT and Kepler missions are collecting data of solar-like oscillating stars of unprecedented quality. Moreover, thanks to the length of the time series, we are able to study their seismic variability. In this work we use numerical simulations based on the last 3 solar cycles to analyze the light curves as a function of the line-of-sight inclination angle. These preliminary results showed that the direct observation of the light curve can induce some bias in the position of the maximum of the cycle.
Indexes and parameters of activity in solar-terrestrial physics
International Nuclear Information System (INIS)
Minasyants, G.S.; Minasyants, T.M.
2005-01-01
The daily variation of different indexes and parameters of the solar-terrestrial physics at the 23 cycle were considered to find the most important from them for the forecast of geomagnetic activity. The validity of application of the Wolf numbers in quality of the characteristic of solar activity at sunspots is confirmed. The best geo-effective parameter in the arrival of the interplanetary shock from coronal mass ejection to an orbit of the Earth. (author)