WorldWideScience

Sample records for thermal electrical central

  1. Centralized vs. decentralized thermal IR inspection policy: experience from a major Brazilian electric power company

    Science.gov (United States)

    dos Santos, Laerte; da Costa Bortoni, Edson; Barbosa, Luiz C.; Araujo, Reyler A.

    2005-03-01

    Furnas Centrais Elétricas S.A is one of the greatest companies of the Brazilian electric power sector and a pioneer in using infrared thermography. In the early 70s, the maintenance policy used was a centralized approach, with only one inspection team to cover all the company"s facilities. In the early 90s, FURNAS decided to decentralize the thermography inspections creating several inspection teams. This new maintenance policy presented several advantages when compared to the previous one. However the credibility of the results obtained with the thermal inspection was frequently being questioned, in part due to the lack of a detailed planning to carry out the transition from the centralized inspection to the decentralized one. In some areas of the company it was suggested the inactivation of the thermography. This paper presents the experience of FURNAS with these different maintenance policies and details the procedures which have been taken that nowadays the infrared thermal inspection has become one of the most important techniques of predictive maintenance in the company.

  2. Solar thermal electricity generation

    Science.gov (United States)

    Gasemagha, Khairy Ramadan

    1993-01-01

    This report presents the results of modeling the thermal performance and economic feasibility of large (utility scale) and small solar thermal power plants for electricity generation. A number of solar concepts for power systems applications have been investigated. Each concept has been analyzed over a range of plant power ratings from 1 MW(sub e) to 300 MW(sub e) and over a range of capacity factors from a no-storage case (capacity factor of about 0.25 to 0.30) up to intermediate load capacity factors in the range of 0.46 to 0.60. The solar plant's economic viability is investigated by examining the effect of various parameters on the plant costs (both capital and O & M) and the levelized energy costs (LEC). The cost components are reported in six categories: collectors, energy transport, energy storage, energy conversion, balance of plant, and indirect/contingency costs. Concentrator and receiver costs are included in the collector category. Thermal and electric energy transport costs are included in the energy transport category. Costs for the thermal or electric storage are included in the energy storage category; energy conversion costs are included in the energy conversion category. The balance of plant cost category comprises the structures, land, service facilities, power conditioning, instrumentation and controls, and spare part costs. The indirect/contingency category consists of the indirect construction and the contingency costs. The concepts included in the study are (1) molten salt cavity central receiver with salt storage (PFCR/R-C-Salt); (2) molten salt external central receiver with salt storage (PFCR/R-E-Salt); (3) sodium external central receiver with sodium storage (PFCR/RE-Na); (4) sodium external central receiver with salt storage (PFCR/R-E-Na/Salt); (5) water/steam external central receiver with oil/rock storage (PFCR/R-E-W/S); (6) parabolic dish with stirling engine conversion and lead acid battery storage (PFDR/SLAB); (7) parabolic dish

  3. Electric Motor Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    Thermal management enables more efficient and cost-effective motors. This Annual Merit Review presentation describes the technical accomplishments and progress in electric motor thermal management R&D over the last year. This project supports a broad industry demand for data, analysis methods, and experimental techniques to improve and better understand motor thermal management.

  4. Methodology for carrying out energy diagnosis in auxiliaries systems in thermal electrical central stations; Metodologia para realizar un diagnostico energetico en sistemas auxiliares de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Nebradt Garcia, Jesus [Comision Federal de Electricidad (CFE), Mexico, D. F. (Mexico); Rojas Hidalgo, Ismael; Huante Perez, Liborio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-12-31

    One of the potential areas for energy saving in Central Electric Power Plants are the auxiliaries system, so as to based in a preliminary energy diagnosis and considering that energy saving measures would be taken, going from the instrumentation, operational changes in equipment, as well as in using velocity variators in motors, it turns out to be that the energy consumption of auxiliaries at 75% load in a 150 MW thermal power plant varies from 3% to 4% and for the case of a 350 MW power plant the energy consumption of the auxiliaries represents 2 to 3.5%. Nowadays this consumption are above 6%. Considering that the country has 40 units with capacities varying from 150 to 350 MW, the economical and the fuel saving would be substantial. This paper will present a summary of the methodology to be used to carry out this type of projects. [Espanol] Una de las areas potenciales de ahorro de energia en centrales termoelectricas son los sistemas auxiliares, de tal manera que basados en un diagnostico energetico preliminar y considerando que se aplicarian las medidas de ahorro de energia que van desde la instrumentacion, cambios operativos en equipos, asi como el uso de variadores de velocidad en motores, se tienen que los consumos de auxiliares para un 75% de carga en una central termoelectrica de 150 MW varian desde un 3% hasta un 4% y para el caso de una central termoelectrica de 350 MW, el consumo de auxiliares representa del 2 al 3.5%. Hoy en dia dichos consumos estan por encima del 6%. Si consideramos que el pais cuenta con 40 unidades que varian desde 150 MW hasta 350 MW, entonces los ahorros economicos y de combustible serian impactantes. La presente ponencia mostrara un resumen de la metodologia a emplear para la realizacion de este tipo de proyectos.

  5. Methodology for carrying out energy diagnosis in auxiliaries systems in thermal electrical central stations; Metodologia para realizar un diagnostico energetico en sistemas auxiliares de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Nebradt Garcia, Jesus [Comision Federal de Electricidad (CFE), Mexico, D. F. (Mexico); Rojas Hidalgo, Ismael; Huante Perez, Liborio [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1999-12-31

    One of the potential areas for energy saving in Central Electric Power Plants are the auxiliaries system, so as to based in a preliminary energy diagnosis and considering that energy saving measures would be taken, going from the instrumentation, operational changes in equipment, as well as in using velocity variators in motors, it turns out to be that the energy consumption of auxiliaries at 75% load in a 150 MW thermal power plant varies from 3% to 4% and for the case of a 350 MW power plant the energy consumption of the auxiliaries represents 2 to 3.5%. Nowadays this consumption are above 6%. Considering that the country has 40 units with capacities varying from 150 to 350 MW, the economical and the fuel saving would be substantial. This paper will present a summary of the methodology to be used to carry out this type of projects. [Espanol] Una de las areas potenciales de ahorro de energia en centrales termoelectricas son los sistemas auxiliares, de tal manera que basados en un diagnostico energetico preliminar y considerando que se aplicarian las medidas de ahorro de energia que van desde la instrumentacion, cambios operativos en equipos, asi como el uso de variadores de velocidad en motores, se tienen que los consumos de auxiliares para un 75% de carga en una central termoelectrica de 150 MW varian desde un 3% hasta un 4% y para el caso de una central termoelectrica de 350 MW, el consumo de auxiliares representa del 2 al 3.5%. Hoy en dia dichos consumos estan por encima del 6%. Si consideramos que el pais cuenta con 40 unidades que varian desde 150 MW hasta 350 MW, entonces los ahorros economicos y de combustible serian impactantes. La presente ponencia mostrara un resumen de la metodologia a emplear para la realizacion de este tipo de proyectos.

  6. Solar thermal central receivers

    International Nuclear Information System (INIS)

    Vant-Hull, L.L.

    1993-01-01

    Market issues, environmental impact, and technology issues related to the Solar Central Receiver concept are addressed. The rationale for selection of the preferred configuration and working fluid are presented as the result of a joint utility-industry analysis. A $30 million conversion of Solar One to an external molten salt receiver would provide the intermediate step to a commercial demonstration plant. The first plant in this series could produce electricity at 11.2 cents/kWhr and the seventh at 8.2 cents/kWhr, completely competitive with projected costs of new utility plants in 1992

  7. Modern techniques for the emissions control in thermal electric stations; Tecnicas modernas para el control de emisiones en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Romo Millares, C. A. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1995-12-31

    This paper presents the techniques and the control equipment for emissions in thermal stations that have the highest possibilities of being considered in the immediate future in the national energy panorama and the established frame for the environmental normativity. The pollutant compounds subject to revision are the nitrogen and sulfur oxides and unburned particles. [Espanol] Se presentan las tecnicas y equipos de control de emisiones para centrales termoelectricas que tienen mayores posibilidades de ser consideradas en el futuro inmediato dentro del panorama energetico nacional y el marco establecido por la normatividad ambiental. Los compuestos contaminantes sujetos a revision son los oxidos de nitrogeno y azufre y las particulas inquemadas.

  8. Modern techniques for the emissions control in thermal electric stations; Tecnicas modernas para el control de emisiones en centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Romo Millares, C A [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    This paper presents the techniques and the control equipment for emissions in thermal stations that have the highest possibilities of being considered in the immediate future in the national energy panorama and the established frame for the environmental normativity. The pollutant compounds subject to revision are the nitrogen and sulfur oxides and unburned particles. [Espanol] Se presentan las tecnicas y equipos de control de emisiones para centrales termoelectricas que tienen mayores posibilidades de ser consideradas en el futuro inmediato dentro del panorama energetico nacional y el marco establecido por la normatividad ambiental. Los compuestos contaminantes sujetos a revision son los oxidos de nitrogeno y azufre y las particulas inquemadas.

  9. Thermal electric power production

    International Nuclear Information System (INIS)

    Boehmer, S.

    2001-01-01

    The basic principle of a thermal power plant is to heat up water in the pipe system of a boiler to generate steam, which exits the boiler with high pressure and releases its energy to a tandem-arranged turbine. This energy is transmitted to a generator over a common shaft. The generated electricity is fed into the power supply system. The processed steam is condensed to water by means of a condenser and transferred back into the pipe system of the boiler (feed water circuit). In general the following techniques are applied for the combustion of solid, liquid and gaseous fuels: dry bottom boiler, wet bottom boiler, grate firing, fluidized bed combustion, gasification systems - integrated gasification combined cycle (IGCC), oil firing technique, gas firing technique. Residues from power plants are generated by the following processes and emission reduction measures: separation of bottom ash or boiler slag in the boiler; separation of fly ash (particulate matter) by means of filters or electric precipitators; desulphurization through lime additive processes, dry sorption or spray absorption processes and lime scrubbing processes; desulphurization according to Wellmann-Lord and to the Walther process; reduction of NO x emissions by selective catalytic reduction (SCR). In this case spent catalyst results as a waste unless it is recycled. No residues are generated by the following measures to reduce NO x emissions: minimization of nitrogen by selective non-catalytic reduction (SNCR); adaptations of the firing technology to avoid emissions - primary measures (low-NO x burners, CO reduction). However, this may change the quality of fly ash by increasing unburnt carbon. Combustion of fossil fuels (with the exception of gaseous fuels) and biomass generates large quantities of residues - with coal being the greatest contributor - either from the fuel itself in the form of ashes, or from flue gas cleaning measures. In coal-fired power plants huge amounts of inorganic residues

  10. The limits to solar thermal electricity

    International Nuclear Information System (INIS)

    Trainer, Ted

    2014-01-01

    The potential and limits of solar thermal power systems depend primarily on their capacity to meet electricity demand in mid-winter, and the associated cost, storage and other implications. Evidence on output and costs is analysed. Most attention is given to central receivers. Problems of low radiation levels, embodied energy costs, variability and storage are discussed and are found to set significant difficulties for large scale solar thermal supply in less than ideal latitudes and seasons. It is concluded that for solar thermal systems to meet a large fraction of anticipated global electricity demand in winter would involve prohibitive capital costs. - Highlights: • Output and capital cost data for various solar thermal technologies is examined. • Special attention is given to performance in winter. • Attention is also given to the effect of solar intermittency. • Implications for storage are considered. • It is concluded that there are significant limits to solar thermal power

  11. Solar energy thermally powered electrical generating system

    Science.gov (United States)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  12. Centralized or decentralized electricity production

    International Nuclear Information System (INIS)

    Boer, H.A. de.

    1975-01-01

    Because of low overall efficiency in electric power generation, it is argued that energy provision based on gas, combined with locally decentralized electricity production, saves for the Netherlands slightly more fossile fuel than nuclear technologies and makes the country independent of uranium resources. The reason the Netherlands persues this approach is that a big part of the energy is finally used for heating in the normal or moderate temperatures

  13. Centralized electricity generation in Africa

    International Nuclear Information System (INIS)

    Jaujay, J.

    2000-01-01

    In Africa, over 90 per cent of the suburban and rural populations do not have access to electricity, even if it represents the engine and consequence of change on the continent. A global approach represents the best way to meet the extensive needs of the continent. The author briefly reviewed the recent projects implemented in Africa to meet the increasing demand. Diesel generators were used to satisfy demand in small electrical sectors (less than 1000 MW), hydroelectricity or combustion turbines were used for medium electrical sectors (1000 to 5000 MW). A discussion of the technologies followed, touching on diesel electric stations and combustion turbines. Both methods meet environmental standards as they apply to emission control and noise control. The choice between the two technologies must be based on required unit power, site isolation, access to gas, and the cost of available combustibles. Hydroelectric power has great potential in the sub-Sahara region, and the challenges faced by each project are similar: difficulty in finding the required financing, meeting the environmental constraints, and the distribution of the energy. A modular nuclear reactor project for the generation of electricity is being developed by ESKOM Enterprises, in association with the British Nuclear Fuel Limited and PECCO and progress will be closely monitored. Decision makers must ensure that appropriate decisions are made in a reasonable time frame to allow sufficient time to develop a project to implementation. Demand requirements must be examined closely, technology adequately selected in order to come up with a financing plan. 4 tabs

  14. Electric Motor Thermal Management R&D

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin

    2016-06-07

    Thermal management enables more efficient and cost-effective motors. This Annual Merit Review presentation describes the technical accomplishments and progress in electric motor thermal management R&D over the last year. This project supports a broad industry demand for data, analysis methods, and experimental techniques to improve and better understand motor thermal management.

  15. Photovoltaic. Solar thermal. Solar thermal electricity

    International Nuclear Information System (INIS)

    2009-01-01

    The year 2008 was excellent for solar energy in the European Union. The growth of the installed capacity for photovoltaic was +159% (it means +4747.018 MW) to reach 9689.952 MW and that for solar thermal was +51.5% (it means +3172.5 MW) to reach 19982.7 MW. Worldwide concentrated solar thermal capacity stood at 679 MW in 2009, while this figure may seem low, the sector has a promising future ahead of it. (A.C.)

  16. Full-energy-chain analysis of greenhouse gas emissions for solar thermal electric power generation systems

    International Nuclear Information System (INIS)

    Norton, B.; Lawson, W.R.

    1997-01-01

    Technical attributes and environmental impacts of solar thermal options for centralized electricity generation are discussed. In particular, the full-energy-chain, including embodied energy and energy production, is considered in relation to greenhouse gas emission arising from solar thermal electricity generation. Central receiver, parabolic dish, parabolic trough and solar pond systems are considered. (author)

  17. Electrical and thermal conductivities in dense plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Faussurier, G., E-mail: gerald.faussurier@cea.fr; Blancard, C.; Combis, P.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2014-09-15

    Expressions for the electrical and thermal conductivities in dense plasmas are derived combining the Chester-Thellung-Kubo-Greenwood approach and the Kramers approximation. The infrared divergence is removed assuming a Drude-like behaviour. An analytical expression is obtained for the Lorenz number that interpolates between the cold solid-state and the hot plasma phases. An expression for the electrical resistivity is proposed using the Ziman-Evans formula, from which the thermal conductivity can be deduced using the analytical expression for the Lorenz number. The present method can be used to estimate electrical and thermal conductivities of mixtures. Comparisons with experiment and quantum molecular dynamics simulations are done.

  18. Electrical power system integrated thermal/electrical system simulation

    International Nuclear Information System (INIS)

    Freeman, W.E.

    1992-01-01

    This paper adds thermal properties to previously developed electrical Saber templates and incorporates these templates into a functional Electrical Power Subsystem (EPS) simulation. These combined electrical and thermal templates enable the complete and realistic simulation of a vehicle EPS on-orbit. Applications include on-orbit energy balance determinations for system load changes, initial array and battery EPS sizing for new EPS development, and array and battery technology trade studies. This effort proves the versatility of the Saber simulation program in handling varied and complex simulations accurately and in a reasonable amount of computer time. 9 refs

  19. Nuclear Electric's central dose record service

    International Nuclear Information System (INIS)

    Goldfinch, E.P.; Mullarkey, D.T.; McWhan, A.W.; Risk, G.; Vaughan, L.

    1991-01-01

    This paper describes the conception, development and operation of the Nuclear Electric Central Dose Record Service, including the initial philosophy considered necessary for a database for a large multi-site organisation, the setting up of the data and current routine operation. Lessons learned are briefly described. CDRS holds 35,000 records in a high security environment. The database includes records of radiation doses received by contractor's employees working at Nuclear Electric sites as well as dose records and dose histories for classified and non classified Nuclear Electric employees. (Author)

  20. Bony ankylosis following thermal and electrical injury

    Energy Technology Data Exchange (ETDEWEB)

    Balen, P.F.; Helms, C.A. [Dept. of Radiology, Duke University Medical Center, Durham, NC (United States)

    2001-07-01

    Objective. Bony ankylosis has been described following trauma, paralysis, psoriasis, Reiter's syndrome, ankylosing spondylitis, juvenile chronic arthritis and rheumatoid arthritis. Reports of bony ankylosis following thermal and electrical injury are limited.Design and patients. Thirteen cases of burn-related joint ankylosis in four patients are presented.Conclusion. Patients with burns from thermal or electrical injury may develop bony ankylosis among other radiographic manifestations. This bony ankylosis may result either from bridging extra-articular heterotopic ossification with preservation of the underlying joint or from intra-articular fusion due to joint destruction. (orig.)

  1. Thermodynamic analysis of pumped thermal electricity storage

    International Nuclear Information System (INIS)

    White, Alexander; Parks, Geoff; Markides, Christos N.

    2013-01-01

    The increasing use of renewable energy technologies for electricity generation, many of which have an unpredictably intermittent nature, will inevitably lead to a greater need for electricity storage. Although there are many existing and emerging storage technologies, most have limitations in terms of geographical constraints, high capital cost or low cycle life, and few are of sufficient scale (in terms of both power and storage capacity) for integration at the transmission and distribution levels. This paper is concerned with a relatively new concept which will be referred to here as Pumped Thermal Electricity Storage (PTES), and which may be able to make a significant contribution towards future storage needs. During charge, PTES makes use of a high temperature ratio heat pump to convert electrical energy into thermal energy which is stored as ‘sensible heat’ in two thermal reservoirs, one hot and one cold. When required, the thermal energy is then converted back to electricity by effectively running the heat pump backwards as a heat engine. The paper focuses on thermodynamic aspects of PTES, including energy and power density, and the various sources of irreversibility and their impact on round-trip efficiency. It is shown that, for given compression and expansion efficiencies, the cycle performance is controlled chiefly by the ratio between the highest and lowest temperatures in each reservoir rather than by the cycle pressure ratio. The sensitivity of round-trip efficiency to various loss parameters has been analysed and indicates particular susceptibility to compression and expansion irreversibility

  2. Solar thermal energy conversion to electrical power

    International Nuclear Information System (INIS)

    Trinh, Anh-Khoi; González, Ivan; Fournier, Luc; Pelletier, Rémi; Sandoval V, Juan C.; Lesage, Frédéric J.

    2014-01-01

    The conversion of solar energy to electricity currently relies primarily on the photovoltaic effect in which photon bombardment of photovoltaic cells drives an electromotive force within the material. Alternatively, recent studies have investigated the potential of converting solar radiation to electricity by way of the Seebeck effect in which charge carrier mobility is generated by an asymmetric thermal differential. The present study builds upon these latest advancements in the state-of-the-art of thermoelectric system management by combining solar evacuated tube technology with commercially available Bismuth Telluride semiconductor modules. The target heat source is solar radiation and the target heat sink is thermal convection into the ambient air relying on wind aided forced convection. These sources of energy are reproduced in a laboratory controlled environment in order to maintain a thermal dipole across a thermoelectric module. The apparatus is then tested in a natural environment. The novelty of the present work lies in a net thermoelectric power gain for ambient environment applications and an experimental validation of theoretical electrical characteristics relative to a varying electrical load. - Highlights: • Solar radiation maintains a thermal tension which drives an electromotive force. • Voltage, current and electric power are reported and discussed. • Theoretical optimal thermoelectric conversion predictions are presented. • Theory is validated with experimentally measured data

  3. Synthesis, structural and electrical characterizations of thermally ...

    African Journals Online (AJOL)

    Synthesis, structural and electrical characterizations of thermally evaporated Cu 2 SnS 3 thin films. ... The surface profilometer shows that the deposited films are rough. The XRD spectra identified the ... The electrical resistivity of the deposited Cu2SnS3 film is 2.55 x 10-3 Ωcm. The conductivity is in the order of 103 Ω-1cm-1.

  4. Peripapillary retinal thermal coagulation following electrical injury

    Directory of Open Access Journals (Sweden)

    Manjari Tandon

    2013-01-01

    Full Text Available In this study, we have presented the case report of a 20 year old boy who suffered an electric injury shock, following which he showed peripapillary retinal opacification and increased retinal thickening that subsequently progressed to retinal atrophy. The fluorescein angiogram revealed normal retinal circulation, thus indicating thermal damage to retina without any compromise to retinal circulation.

  5. Electrical-thermal coupling of induction machine for improved ...

    African Journals Online (AJOL)

    Electrical-thermal coupling of induction machine for improved thermal performance. ... Nigerian Journal of Technology ... The interaction of its electrical and mechanical parts leads to an increase in temperature which if not properly monitored ...

  6. Electricity storage using a thermal storage scheme

    Energy Technology Data Exchange (ETDEWEB)

    White, Alexander, E-mail: ajw36@cam.ac.uk [Hopkinson Laboratory, Cambridge University Engineering Department, Trumpington Street, Cambridge. CB2 1PZ (United Kingdom)

    2015-01-22

    The increasing use of renewable energy technologies for electricity generation, many of which have an unpredictably intermittent nature, will inevitably lead to a greater demand for large-scale electricity storage schemes. For example, the expanding fraction of electricity produced by wind turbines will require either backup or storage capacity to cover extended periods of wind lull. This paper describes a recently proposed storage scheme, referred to here as Pumped Thermal Storage (PTS), and which is based on “sensible heat” storage in large thermal reservoirs. During the charging phase, the system effectively operates as a high temperature-ratio heat pump, extracting heat from a cold reservoir and delivering heat to a hot one. In the discharge phase the processes are reversed and it operates as a heat engine. The round-trip efficiency is limited only by process irreversibilities (as opposed to Second Law limitations on the coefficient of performance and the thermal efficiency of the heat pump and heat engine respectively). PTS is currently being developed in both France and England. In both cases, the schemes operate on the Joule-Brayton (gas turbine) cycle, using argon as the working fluid. However, the French scheme proposes the use of turbomachinery for compression and expansion, whereas for that being developed in England reciprocating devices are proposed. The current paper focuses on the impact of the various process irreversibilities on the thermodynamic round-trip efficiency of the scheme. Consideration is given to compression and expansion losses and pressure losses (in pipe-work, valves and thermal reservoirs); heat transfer related irreversibility in the thermal reservoirs is discussed but not included in the analysis. Results are presented demonstrating how the various loss parameters and operating conditions influence the overall performance.

  7. Electrical and thermal modeling of railguns

    International Nuclear Information System (INIS)

    Kerrisk, J.F.

    1984-01-01

    Electrical and thermal modeling of railguns at Los Alamos has been done for two purposes: (1) to obtain detailed information about the behavior of specific railgun components such as the rails, and (2) to predict overall performance of railgun tests. Detailed electrical and thermal modeling has concentrated on calculations of the inductance and surface current distribution of long parallel conductors in the high-frequency limit and on calculations of current and thermal diffusion in rails. Inductance calculations for various rail cross sections and for magnetic flux compression generators (MFCG) have been done. Inductance and current distribution results were compared with experimental measurements. Twodimensional calculations of current and thermal diffusion in rail cross sections have been done; predictions of rail heating and melting as a function of rail size and total current have been made. An overall performance model of a railgun and power supply has been developed and used to design tests at Los Alamos. The lumped-parameter circuit model uses results from the detailed inductance and current diffusion calculations along with other circuit component models to predict rail current and projectile acceleration, velocity, and position as a function of time

  8. Solar thermal electric power information user study

    Energy Technology Data Exchange (ETDEWEB)

    Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

    1981-02-01

    The results of a series of telephone interviews with groups of users of information on solar thermal electric power are described. These results, part of a larger study on many different solar technologies, identify types of information each group needed and the best ways to get information to each group. The report is 1 of 10 discussing study results. The overall study provides baseline data about information needs in the solar community. An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from five solar thermal electric power groups of respondents are analyzed: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Utilities, Electric Power Engineers, and Educators. The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

  9. Electric Motor Thermal Management R&D. Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-04-01

    With the push to reduce component volumes, lower costs, and reduce weight without sacrificing performance or reliability, the challenges associated with thermal management increase for power electronics and electric motors. Thermal management for electric motors will become more important as the automotive industry continues the transition to more electrically dominant vehicle propulsion systems. The transition to more electrically dominant propulsion systems leads to higher-power duty cycles for electric drive systems. Thermal constraints place significant limitations on how electric motors ultimately perform, and as thermal management improves, there will be a direct trade-off between motor performance, efficiency, cost, and the sizing of electric motors to operate within the thermal constraints. The goal of this research project is to support broad industry demand for data, analysis methods, and experimental techniques to improve and better understand motor thermal management. Work in FY15 focused on two areas related to motor thermal management: passive thermal performance and active convective cooling. Passive thermal performance emphasized the thermal impact of materials and thermal interfaces among materials within an assembled motor. The research tasks supported the publication of test methods and data for thermal contact resistances and direction-dependent thermal conductivity within an electric motor. Active convective cooling focused on measuring convective heat-transfer coefficients using automatic transmission fluid (ATF). Data for average convective heat transfer coefficients for direct impingement of ATF jets was published. Also, experimental hardware for mapping local-scale and stator-scale convective heat transfer coefficients for ATF jet impingement were developed.

  10. Solar thermal power systems point-focusing thermal and electric applications projects. Volume 1: Executive summary

    Science.gov (United States)

    Marriott, A.

    1980-01-01

    The activities of the Point-Focusing Thermal and Electric Applications (PETEA) project for the fiscal year 1979 are summarized. The main thrust of the PFTEA Project, the small community solar thermal power experiment, was completed. Concept definition studies included a small central receiver approach, a point-focusing distributed receiver system with central power generation, and a point-focusing distributed receiver concept with distributed power generation. The first experiment in the Isolated Application Series was initiated. Planning for the third engineering experiment series, which addresses the industrial market sector, was also initiated. In addition to the experiment-related activities, several contracts to industry were let and studies were conducted to explore the market potential for point-focusing distributed receiver (PFDR) systems. System analysis studies were completed that looked at PFDR technology relative to other small power system technology candidates for the utility market sector.

  11. High thermal conductivity connector having high electrical isolation

    Science.gov (United States)

    Nieman, Ralph C.; Gonczy, John D.; Nicol, Thomas H.

    1995-01-01

    A method and article for providing a low-thermal-resistance, high-electrical-isolation heat intercept connection. The connection method involves clamping, by thermal interference fit, an electrically isolating cylinder between an outer metallic ring and an inner metallic disk. The connection provides durable coupling of a heat sink and a heat source.

  12. Electrically conductive carbon nanofiber/paraffin wax composites for electric thermal storage

    International Nuclear Information System (INIS)

    Zhang Kun; Han Baoguo; Yu Xun

    2012-01-01

    Highlights: ► Carbon nanofiber (CNF)/paraffin wax composite is found to be a promising electric thermal storage material. ► The thermal storage capacity of CNF/paraffin wax composite is five times of traditional electric thermal storage material. ► CNF is shown to be an effective conductive filler for the composite. - Abstract: The research of electric thermal storage (ETS) has attracted a lot of attention recently, which converts off-peak electrical energy into thermal energy and release it later at peak hours. In this study, new electric thermal storage composites are developed by employing paraffin wax as thermal storage media and carbon nanofiber (CNF) as conductive fillers. Electric heating and thermal energy release performances of the CNF/paraffin wax composites are experimentally investigated. Experimental results show that, when the composites are heated to about 70 °C, the developed electrically conductive CNF/paraffin wax composites present a thermal storage capacity of about 280 kJ/kg, which is five times of that of traditional thermal storage medium such as ceramic bricks (54 kJ/kg). The CNF/paraffin wax composites can also effectively store the thermal energy and release the thermal energy in later hours.

  13. Electricity in Central Asia: Market and investment opportunity report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-09-15

    This WEC report examines the vast interdependent electricity systems of the Central Asian states; Kazakhstan, Kyrgyzstan (Kyrgyz Republic), Tajikistan, Turkmenistan, and Uzbekistan. The report outlines the progress of market reform in this region and identifies the potential for investment opportunities.

  14. Economic aspects of Solar Thermal Technologies for electricity generation

    International Nuclear Information System (INIS)

    Meinecke, W.

    1993-01-01

    Economic results of German studies are presented, which compare the four solar thermal technologies for electricity generation (parabolic trough collector system, central receiver system, parabolic dish/Stirling system, solar chimney plant). These studies were carried out by Interatom (today Siemens/KWU) in Bergisch Gladbach, Flachglas Solartechnik in Koln and Schlaich Bergermann and Partner in Stuggart under contract of DLR in Koln. Funds were made available by the German Ministry of Research and Development (BMFT). The results indicate that all of the investigated technologies have the potential to reduce the generating costs and that in the future costs of below 0.30 DM/kWh could be expected under excellent insolation conditions (e.G. 2850 kWh/m''2 a direct insolation as in California/USA). (Author) 25 refs

  15. Analysis Of ElectricalThermal Coupling Of Induction Machine ...

    African Journals Online (AJOL)

    The interaction of the Electrical and mechanical parts of Electrical machines gives rise to the heating of the machine's constituent parts. This consequently leads to an increase in temperature which if not properly monitored may lead to the breakdown of the machine. This paper therefore presents the Electrical and thermal ...

  16. Thermal Management of Power Electronics and Electric Motors for Electric-Drive Vehicles (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, S.

    2014-09-01

    This presentation is an overview of the power electronics and electric motor thermal management and reliability activities at NREL. The focus is on activities funded by the Department of Energy Vehicle Technologies Office Advanced Power Electronics and Electric Motors Program.

  17. Centralized electricity generation in offshore wind farms using hydraulic networks

    NARCIS (Netherlands)

    Jarquin Laguna, A.

    2017-01-01

    The work presented in this thesis explores a new way of generation, collection and transmission of wind energy inside a wind farm, in which the electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A centralized

  18. Electrically Driven Thermal Management: Flight Validation, Experiment Development, Future Technologies

    Science.gov (United States)

    Didion, Jeffrey R.

    2018-01-01

    Electrically Driven Thermal Management is an active research and technology development initiative incorporating ISS technology flight demonstrations (STP-H5), development of Microgravity Science Glovebox (MSG) flight experiment, and laboratory-based investigations of electrically based thermal management techniques. The program targets integrated thermal management for future generations of RF electronics and power electronic devices. This presentation reviews four program elements: i.) results from the Electrohydrodynamic (EHD) Long Term Flight Demonstration launched in February 2017 ii.) development of the Electrically Driven Liquid Film Boiling Experiment iii.) two University based research efforts iv.) development of Oscillating Heat Pipe evaluation at Goddard Space Flight Center.

  19. Perspectives for nuclear electricity in Central Africa

    International Nuclear Information System (INIS)

    Wa Kalenga, M.

    1977-01-01

    The paper analyses the energy system of the Central African countries and evaluates the projected global demand of energy. It compares the economy of the nuclear solution for satisfying future demands in relation to other forms of energy available in the region. Finally, it discusses the role that the countries involved can play in the fuel cycle (supply of raw material, possibilities of fuel enrichment). (author)

  20. Perspectives for nuclear electricity in central Africa

    International Nuclear Information System (INIS)

    Wa Kalenga, M.

    1977-01-01

    The paper analyses the energetic system of Central African countries and evaluate the projected global demand of energy. It compares the economy of the nuclear solution for the satisfaction of future demand versus other forms of energy available in the region. It appreciates finally the role that the countries involved can play in the fuel cycle (supply of raw material, possibilities of fuel enrichment) [fr

  1. Electrical, thermal and abusive tests on lithium thionyl chloride cells

    Science.gov (United States)

    Frank, H. A.

    1980-04-01

    Electrical characterizations, thermal characterizations, and outer limits tests of lithium thionyl chloride cells are discussed. Graphs of energy density vs power density and heat rate vs time are presented along with results of forced reversal and high rate discharge tests.

  2. Superconducting Electric Boost Pump for Nuclear Thermal Propulsion, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A submersible, superconducting electric boost pump sized to meet the needs of future Nuclear Thermal Propulsion systems in the 25,000 lbf thrust range is proposed....

  3. Thermal and electrical conductivities of Cd-Zn alloys

    International Nuclear Information System (INIS)

    Saatci, B; Ari, M; Guenduez, M; Meydaneri, F; Bozoklu, M; Durmus, S

    2006-01-01

    The composition and temperature dependences of the thermal and electrical conductivities of three different Cd-Zn alloys have been investigated in the temperature range of 300-650 K. Thermal conductivities of the Cd-Zn alloys have been determined by using the radial heat flow method. It has been found that the thermal conductivity decreases slightly with increasing temperature and the data of thermal conductivity are shifting together to the higher values with increasing Cd composition. In addition, the electrical measurements were determined by using a standard DC four-point probe technique. The resistivity increases linearly and the electrical conductivity decreases exponentially with increasing temperature. The resistivity and electrical conductivity are independent of composition of Cd and Zn. Also, the temperature coefficient of Cd-Zn alloys has been determined, which is independent of composition of Cd and Zn. Finally, Lorenz number has been calculated using the thermal and electrical conductivity values at 373 and 533 K. The results satisfy the Wiedemann-Franz (WF) relation at T 373 K), the WF relation could not hold and the phonon component contribution of thermal conductivity dominates the thermal conduction

  4. PV Thermal systems: PV panels supplying renewable electricity and heat

    NARCIS (Netherlands)

    Helden, van W.G.J.; Zolingen, van R.J.C.; Zondag, H.A.

    2004-01-01

    With PV Thermal panels sunlight is converted into electricity and heat simultaneously. Per unit area the total efficiency of a PVT panel is higher than the sum of the efficiencies of separate PV panels and solar thermal collectors. During the last 20 years research into PVT techniques and concepts

  5. Effective electrical and thermal conductivity of multifilament twisted superconductors

    International Nuclear Information System (INIS)

    Chechetkin, V.R.

    2013-01-01

    The effective electrical and thermal conductivity of composite wire with twisted superconducting filaments embedded into normal metal matrix is calculated using the extension of Bruggeman method. The resistive conductivity of superconducting filaments is described in terms of symmetric tensor, whereas the conductivity of a matrix is assumed to be isotropic and homogeneous. The dependence of the resistive electrical conductivity of superconducting filaments on temperature, magnetic field, and current density is implied to be parametric. The resulting effective conductivity tensor proved to be non-diagonal and symmetric. The non-diagonal transverse–longitudinal components of effective electrical conductivity tensor are responsible for the redistribution of current between filaments. In the limits of high and low electrical conductivity of filaments the transverse effective conductivity tends to that of obtained previously by Carr. The effective thermal conductivity of composite wires is non-diagonal and radius-dependent even for the isotropic and homogeneous thermal conductivities of matrix and filaments.

  6. Improving Thermal and Electrical Efficiency in Photovoltaic Thermal Systems for Sustainable Cooling System Integration

    Directory of Open Access Journals (Sweden)

    Mohammad Alobaid

    2018-06-01

    Full Text Available Research into photovoltaic thermal systems is important in solar technologies as photovoltaic thermal systems are designed to produce both electrical and thermal energy, this can lead to improved performance of the overall system. The performance of photovoltaic thermal systems is based on several factors that include photovoltaic thermal materials, design, ambient temperature, inlet and outlet fluid temperature and photovoltaic cell temperature. The aim of this study is to investigate the effect of photovoltaic thermal outlet water temperatures and solar cell temperature on both electrical and thermal efficiency for different range of inlet water temperature. To achieve this, a mathematical model of a photovoltaic thermal system was developed to calculate the anticipated system performance. The factors that affect the efficiency of photovoltaic thermal collectors were discussed and the outlet fluid temperature from the photovoltaic thermal is investigated in order to reach the highest overall efficiency for the solar cooling system. An average thermal and electrical efficiency of 65% and 13.7%, respectively, was achieved and the photovoltaic thermal mathematical model was validated with experimental data from literature.

  7. Electrical and thermal behavior of unsaturated soils: experimental results

    Science.gov (United States)

    Nouveau, Marie; Grandjean, Gilles; Leroy, Philippe; Philippe, Mickael; Hedri, Estelle; Boukcim, Hassan

    2016-05-01

    When soil is affected by a heat source, some of its properties are modified, and in particular, the electrical resistivity due to changes in water content. As a result, these changes affect the thermal properties of soil, i.e., its thermal conductivity and diffusivity. We experimentally examine the changes in electrical resistivity and thermal conductivity for four soils with different grain size distributions and clay content over a wide range of temperatures, from 20 to 100 °C. This temperature range corresponds to the thermal conditions in the vicinity of a buried high voltage cable or a geothermal system. Experiments were conducted at the field scale, at a geothermal test facility, and in the laboratory using geophysical devices and probing systems. The results show that the electrical resistivity decreases and the thermal conductivity increases with temperature up to a critical temperature depending on soil types. At this critical temperature, the air volume in the pore space increases with temperature, and the resulting electrical resistivity also increases. For higher temperatures , the thermal conductivity increases sharply with temperature up to a second temperature limit. Beyond it, the thermal conductivity drops drastically. This limit corresponds to the temperature at which most of the water evaporates from the soil pore space. Once the evaporation is completed, the thermal conductivity stabilizes. To explain these experimental results, we modeled the electrical resistivity variations with temperature and water content in the temperature range 20 - 100°C, showing that two critical temperatures influence the main processes occurring during heating at temperatures below 100 °C.

  8. A thermal study of an encapsulated electrical transformer

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, A. [Unidad Geotermia, Temixco (Mexico). Instituto de Investigaciones Electricas; Espinosa-Paredes, G. [Universidad Autonoma Metropolitana, Vicentina (Mexico). Dpto. de Ingenieria de Procesos e Hidraulica; Hernandez, I. [Centro de Sistemas de Manufactura, Nuevo Leon (Mexico). Instituto Tecnologico y de Estudios Superiores de Monterrey

    2002-11-01

    A thermal study of a 45 KVA-prototype encapsulated transformer is described. Casting resin systems were used as insulating systems for encapsulated electric transformers. Normal transformer operation is at full load and, thus the conductor and insulating system becomes hot owing to current circulation through the winding. To determine the various temperature distributions throughout the transformer, the thermal properties of the insulating system and boundary conditions must be known, so that hot spots are located via numerical modelling and maximum permissible temperatures are not attained. Results presented herein include thermal conductivity, thermal diffusivity, and specific heat capacity. Thermal conductivity was obtained experimentally by means of the line-source technique at various temperatures, between room temperature and 155{sup o}C which is the thermal limit of class F insulators. The thermal diffusivity was obtained by parameter estimation by fitting an approximate analytical model to the temperature-time data of the thermal conductivity experiment. Specific heat capacity was obtained from the definition of thermal diffusivity and the insulating-system density. In order to improve the electrical performance of the transformer criteria, a numerical simulation of the different dielectric structures was made using computer program. The boundary conditions for the thermal simulation stage were also determined experimentally from temperature test runs. Finally, in order to obtain data for thermal design, a numerical simulation of the high tension winding was carried out. The thermal simulation stage was performed at different current densities in the conductor with and without electrostatic shields to determine the temperature field and maximum attainable temperatures. Maximum transformer temperature were found to be 15-20{sup o}C below its thermal limit and a correlation of maximum temperature as function of circulating current was developed for design

  9. Electrical and thermal properties of graphite/polyaniline composites

    Energy Technology Data Exchange (ETDEWEB)

    Bourdo, Shawn E., E-mail: sxbourdo@ualr.edu [Center for Integrative Nanotechnology Sciences, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States); Warford, Brock A.; Viswanathan, Tito [Department of Chemistry, University of Arkansas at Little Rock, 2801 South University Avenue, Little Rock, AR 72204 (United States)

    2012-12-15

    A composite of a carbon allotrope (graphite) and an inherently conducting polymer, polyaniline (PANI), has been prepared that exhibits an electrical conductivity greater than either of the two components. An almost 2-fold increase in the bulk conductivity occurs when only a small mass fraction of polyaniline exists in the composite (91% graphite/ 9% polyaniline, by mass). This increase in dc electrical conductivity is curious since in most cases a composite material will exhibit a conductivity somewhere between the two individual components, unless a modification to the electronic nature of the material occurs. In order to elucidate the fundamental electrical properties of the composite we have performed variable temperature conductivity measurements to better understand the nature of conduction in these materials. The results from these studies suggest a change in the mechanism of conduction as the amount of polyaniline is increased in the composite. Along with superior electrical properties, the composites exhibit an increase in thermal stability as compared to the graphite. - Graphical abstract: (Left) Room temperature electrical conductivity of G-PANI composites at different mass ratios. (Right) Electrical conductivity of G-PANI composites at temperatures from 5 K to 300 K. Highlights: Black-Right-Pointing-Pointer Composites of graphite and polyaniline have been synthesized with unique electrical and thermal properties. Black-Right-Pointing-Pointer Certain G-PANI composites are more conductive and more thermally stable than graphite alone. Black-Right-Pointing-Pointer G-PANI composites exhibit a larger conductivity ratio with respect to temperature than graphite alone.

  10. Thermal and Electrical Conductivity Measurements of CDA 510 Phosphor Bronze

    Science.gov (United States)

    Tuttle, James E.; Canavan, Edgar; DiPirro, Michael

    2009-01-01

    Many cryogenic systems use electrical cables containing phosphor bronze wire. While phosphor bronze's electrical and thermal conductivity values have been published, there is significant variation among different phosphor bronze formulations. The James Webb Space Telescope (JWST) will use several phosphor bronze wire harnesses containing a specific formulation (CDA 510, annealed temper). The heat conducted into the JWST instrument stage is dominated by these harnesses, and approximately half of the harness conductance is due to the phosphor bronze wires. Since the JWST radiators are expected to just keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used. We describe an experiment which measured the electrical and thermal conductivity of this material between 4 and 295 Kelvin.

  11. Thermal and Electrical Characterization of Alumina Substrate for Microelectronic Applications

    International Nuclear Information System (INIS)

    Ahmad, S.; Ibrahim, A.; Alias, R.; Shapee, S. M.; Ambak, Z.; Zakaria, S. Z.; Yahya, M. R.; Mat, A. F. A.

    2010-01-01

    This paper reports the effect of sintering temperature on thermal and electrical properties of alumina material as substrate for microelectronic devices. Alumina materials in the form of green sheet with 1 mm thickness were sintered at 1100 deg. C, 1300 deg. C and 1500 deg. C for about 20 hours using heating and cooling rates of 2 deg. C/min. The densities were measured using densitometer and the microstructures of the samples were analyzed using SEM micrographs. Meanwhile thermal and electrical properties of the samples were measured using flash method and impedance analyzer respectively. It was found that thermal conductivity and thermal diffusivity of the substrate increases as sintering temperature increases. It was found also that the dielectric constant of alumina substrate increases as the sintering temperature increases.

  12. Thermal and Electrical Characterization of Alumina Substrate for Microelectronic Applications

    Science.gov (United States)

    Ahmad, S.; Ibrahim, A.; Alias, R.; Shapee, S. M.; Ambak, Z.; Zakaria, S. Z.; Yahya, M. R.; Mat, A. F. A.

    2010-03-01

    This paper reports the effect of sintering temperature on thermal and electrical properties of alumina material as substrate for microelectronic devices. Alumina materials in the form of green sheet with 1 mm thickness were sintered at 1100° C, 1300° C and 1500° C for about 20 hours using heating and cooling rates of 2° C/min. The densities were measured using densitometer and the microstructures of the samples were analyzed using SEM micrographs. Meanwhile thermal and electrical properties of the samples were measured using flash method and impedance analyzer respectively. It was found that thermal conductivity and thermal diffusivity of the substrate increases as sintering temperature increases. It was found also that the dielectric constant of alumina substrate increases as the sintering temperature increases.

  13. Thermal and electrical conductivities of high purity tantalum

    International Nuclear Information System (INIS)

    Archer, S.L.

    1978-01-01

    The electrical resistivity and thermal conductivity of three high purity tantalum samples have been measured as functions of temperature over a temperature range of 5K to 65K. Sample purities ranged up to a resistivity ratio of 1714. The highest purity sample had a residual resistivity of .76 x 10 -10 OMEGA-m. The intrinsic resistivity varied as T 3 . 9 from 10K to 31K. The thermal conductivity of the purest sample had a maximum of 840 W/mK at 9.8K. The intrinsic thermal resistivity varied as T 2 . 4 from 10K to 35K. At low temperatures electrons were scattered primarily by impurities and by phonons with both interband and intraband transitions observed. The electrical and thermal resistivity is departed from Matthiessen's rule at low temperatures

  14. Problems associated with accelerated thermal aging of electrical equipment

    International Nuclear Information System (INIS)

    Isgro, J.R.

    1984-01-01

    This paper discusses the potential problems that may be experienced when accounting for aging mechanisms in organic polymers when utilizing accelerated thermal aging techniques for electrical equipment qualification. Included are discussions of actual experiences and problems encountered in the qualification of electrical and electronic equipment for a complete nuclear power plant. The wide variety of approaches to thermal accelerated aging by various manufacturers of diverse equipment types provides depth to the discussion. A description of how to account for aging mechanisms is also presented

  15. Thermal energy storage for electricity-driven space heating in a day-ahead electricity market

    DEFF Research Database (Denmark)

    Pensini, Alessandro

    2012-01-01

    Thermal Energy Storage (TES) in a space heating (SH) application was investigated. The study aimed to determine the economic benefits of introducing TES into an electricity-driven SH system under a day-ahead electricity market. The performance of the TES was assessed by comparing the cost...... of electricity in a system with a TES unit to the case where no storage is in use and the entire heat requirement is fulfilled by purchasing electricity according to the actual load. The study had two goals: 1. Determining how the size – in terms of electricity input (Pmax) and energy capacity (Emax...

  16. Thermal burn and electrical injuries among electric utility workers, 1995-2004.

    Science.gov (United States)

    Fordyce, Tiffani A; Kelsh, Michael; Lu, Elizabeth T; Sahl, Jack D; Yager, Janice W

    2007-03-01

    This study describes the occurrence of work-related injuries from thermal-, electrical- and chemical-burns among electric utility workers. We describe injury trends by occupation, body part injured, age, sex, and circumstances surrounding the injury. This analysis includes all thermal, electric, and chemical injuries included in the Electric Power Research Institute (EPRI) Occupational Health and Safety Database (OHSD). There were a total of 872 thermal burn and electric shock injuries representing 3.7% of all injuries, but accounting for nearly 13% of all medical claim costs, second only to the medical costs associated with sprain- and strain-related injuries (38% of all injuries). The majority of burns involved less than 1 day off of work. The head, hands, and other upper extremities were the body parts most frequently injured by burns or electric shocks. For this industry, electric-related burns accounted for the largest percentage of burn injuries, 399 injuries (45.8%), followed by thermal/heat burns, 345 injuries (39.6%), and chemical burns, 51 injuries (5.8%). These injuries also represented a disproportionate number of fatalities; of the 24 deaths recorded in the database, contact with electric current or with temperature extremes was the source of seven of the fatalities. High-risk occupations included welders, line workers, electricians, meter readers, mechanics, maintenance workers, and plant and equipment operators.

  17. Optimisation of a Kalina cycle for a central receiver solar thermal power plant with direct steam generation

    DEFF Research Database (Denmark)

    Modi, Anish; Haglind, Fredrik

    2014-01-01

    Central receiver solar thermal power plants are regarded as one of the promising ways to generate electricity in near future. They offer the possibility of using high temperatures and pressures to achieve high efficiencies with standard power cycles. A direct steam generation approach can be used...

  18. The Future of Centrally-Organized Wholesale Electricity Markets

    Energy Technology Data Exchange (ETDEWEB)

    Glazer, Craig [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Morrison, Jay [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Breakman, Paul [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Clements, Allison [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Schwartz, Lisa [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-06-21

    The electricity grid in the United States is organized around a network of large, centralized power plants and high voltage transmission lines that transport electricity, sometimes over large distances, before it is delivered to the customer through a local distribution grid. This network of centralized generation and high voltage transmission lines is called the “bulk power system.” Costs relating to bulk power generation typically account for more than half of a customer’s electric bill.1 For this reason, the structure and functioning of wholesale electricity markets have major impacts on costs and economic value for consumers, as well as energy security and national security. Diverse arrangements for bulk power wholesale markets have evolved over the last several decades. The Southeast and Western United States outside of California have a “bilateral-based” bulk power system where market participants enter into long-term bilateral agreements — using competitive procurements through power marketers, direct arrangements among utilities or with other generation owners, and auctions and exchanges.

  19. Evaluation of Electrical and Thermal Conductivity of Polymeric ...

    African Journals Online (AJOL)

    PROF HORSFALL

    ABSTRACT: This work being gingered by the big menace being posed on our environment by polymeric waste and it's rechanneling involved the studying of the electrical and thermal conductivities of the polymers PP, PE, PS and nylon66 doped with charcoal and graphite. Five grams of each polymer was mixed with ...

  20. Electrically and Thermally Insulated Joint for Liquid Nitrogen Transfer

    DEFF Research Database (Denmark)

    Rasmussen, Carsten; Jensen, Kim Høj; Holbøll, Joachim T.

    1999-01-01

    A prototype of a superconducting cable is currently under construction. The cable conductor is cooled by liquid nitrogen in order to obtain superconductivity. The peripheral cooling circuit is kept at ground potential. This requires a joint which insulates both electrically and thermally...

  1. Experience of Milled Peat Burning at Thermal Electric Power Plant

    Directory of Open Access Journals (Sweden)

    G. I. Zhikhar

    2013-01-01

    Full Text Available The paper presents extensive knowledge and practical experience on burning of milled peat in the boilers of thermal electric power plants in Belarus and Russia. The accumulated experience can be used for solution of problems pertaining to substitution of some types of fuel imported to Belarus by milled peat which is extracted at many fuel effective peat enterprises of the Republic.

  2. Morphology, thermal, electrical and electrochemical stability of nano

    Indian Academy of Sciences (India)

    In the present work, an attempt has been made to develop nano aluminium oxide (Al2O3)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase ...

  3. Evaluation of electrical and thermal conductivity of polymeric wastes ...

    African Journals Online (AJOL)

    This work being gingered by the big menace being posed on our environment by polymeric waste and it's rechanneling involved the studying of the electrical and thermal conductivities of the polymers PP, PE, PS and nylon66 doped with charcoal and graphite. Five grams of each polymer was mixed with varying ...

  4. Utilizing primary energy savings and exergy destruction to compare centralized thermal plants and cogeneration/trigeneration systems

    International Nuclear Information System (INIS)

    Espirito Santo, Denilson Boschiero do; Gallo, Waldyr Luiz Ribeiro

    2017-01-01

    Rising energy conversion processes efficiencies reduces CO_2 emissions and global warming implications. Decentralized electricity production through cogeneration/trigeneration systems can save primary energy if it operates with high efficiency. High efficiency is obtained when the system produces electricity and a substantial amount of the energy rejected by the prime mover is used to meet site thermal demands. Environmental concerns and international agreements are directing governments of different countries to incentive high efficiency solutions. Centralized thermal plants and cogeneration/trigeneration efficiency are compared through efficiency indicators using the first law of thermodynamics and the second law of thermodynamics. This paper proposes the use of the primary energy savings analysis and the exergy destruction analysis to compare decentralized power production through cogeneration/trigeneration systems and centralized thermal plants. The analysis concluded that both methods achieve the same results if the thermal efficiency indicator is used to compare the methods. The analysis also revealed that trigeneration systems with the same energy input are comparable with quite different thermal efficiency centralized thermal plants. Case 1 is comparable to a 53% thermal efficiency power plant and case 2 is comparable to a 77% thermal efficiency power plant. - Highlights: • Trigeneration and thermal plants are compared using PES and exergy destruction. • The thermal efficiency indicator is used to compare both methods. • The same equivalent thermal efficiency is achieved by both methods. • Same energy input trigeneration is similar to different thermal efficiency plants. • Evaluated trigeneration are comparable to a 53–77% thermal efficiency power plant.

  5. Electricity pricing model in thermal generating stations under deregulation

    International Nuclear Information System (INIS)

    Reji, P.; Ashok, S.; Moideenkutty, K.M.

    2007-01-01

    In regulated public utilities with competitive power markets, deregulation has replaced the monopoly. Under the deregulated power market, the electricity price primarily depends on market mechanism and power demand. In this market, generators generally follow marginal pricing. Each generator fixes the electricity price based on their pricing strategy and it leads to more price volatility. This paper proposed a model to determine the electricity price considering all operational constraints of the plant and economic variables that influenced the price, for a thermal generating station under deregulation. The purpose of the model was to assist existing stations, investors in the power sector, regulatory authorities, transmission utilities, and new power generators in decision-making. The model could accommodate price volatility in the market and was based on performance incentive/penalty considering plant load factor, availability of the plant and peak/ off peak demand. The model was applied as a case study to a typical thermal utility in India to determine the electricity price. It was concluded that the case study of a thermal generating station in a deregulated environment showed that the electricity price mainly depended on the gross calorific value (GCV) of fuel, mode of operation, price of the fuel, and operating charges. 11 refs., 2 tabs., 1 fig

  6. Thermal and Electrical Analysis of Mars Rover RTGs

    Energy Technology Data Exchange (ETDEWEB)

    Schock, Alfred; Or, Chuen T; Skrabek, Emanuel A

    2012-01-19

    The RTG designs described in the preceding paper in these proceedings were analyzed for their thermal and electrical performance. Each analysis consisted of coupled thermal, thermoelectric, and electrical analyses, using Fairchild-generated specialized computer codes. These were supplemented with preliminary structural and mass analyses. For each design, various cases representing different operating conditions (water-cooled/radiation-cooled, BOM/EOM, summer/winter, day/night) and different thermoelectric performance assumptions (from conservative to optimistic) were analyzed; and for every case, the heat flow rates, temperatures and electrical performance of each layer of thermoelectric elements and of the overall RTG were determined. The analyses were performed in great detail, to obtain accurate answers permitting meaningful comparisons between different designs. The results presented show the RTG performance achievable with current technology, and the performance improvements that would be achievable with various technology developments.

  7. The performance of residential micro-cogeneration coupled with thermal and electrical storage

    Science.gov (United States)

    Kopf, John

    Over 80% of residential secondary energy consumption in Canada and Ontario is used for space and water heating. The peak electricity demands resulting from residential energy consumption increase the reliance on fossil-fuel generation stations. Distributed energy resources can help to decrease the reliance on central generation stations. Presently, distributed energy resources such as solar photovoltaic, wind and bio-mass generation are subsidized in Ontario. Micro-cogeneration is an emerging technology that can be implemented as a distributed energy resource within residential or commercial buildings. Micro-cogeneration has the potential to reduce a building's energy consumption by simultaneously generating thermal and electrical power on-site. The coupling of a micro-cogeneration device with electrical storage can improve the system's ability to reduce peak electricity demands. The performance potential of micro-cogeneration devices has yet to be fully realized. This research addresses the performance of a residential micro-cogeneration device and it's ability to meet peak occupant electrical loads when coupled with electrical storage. An integrated building energy model was developed of a residential micro-cogeneration system: the house, the micro-cogeneration device, all balance of plant and space heating components, a thermal storage device, an electrical storage device, as well as the occupant electrical and hot water demands. This model simulated the performance of a micro-cogeneration device coupled to an electrical storage system within a Canadian household. A customized controller was created in ESP-r to examine the impact of various system control strategies. The economic performance of the system was assessed from the perspective of a local energy distribution company and an end-user under hypothetical electricity export purchase price scenarios. It was found that with certain control strategies the micro-cogeneration system was able to improve the

  8. Thermal footprints in groundwater of central European cities

    Science.gov (United States)

    Bayer, P.; Menberg, K.; Blum, P.

    2014-12-01

    Atmospheric thermal pollution in densely populated areas is recognized as a severe problem with consequences for human health, and considerable efforts are being taken to mitigate heat stress in cities. However, anthropogenic activities also influence the thermal environment beneath the ground level, with commonly growing temperatures that affect groundwater ecology and geothermal use efficiency. In our work, we identify the controlling mechanisms for the long-term evolution of such urban heat islands. The shallow groundwater temperatures in several central European cities such as Cologne, Karlsruhe, Munich, Berlin and Zurich were mapped at high spatial and temporal resolution. Thermal anomalies were found to be highly heterogeneous with local hot spots showing temperatures of more than 20°C. Accordingly, these urban regions show a considerable groundwater warming in comparison to undisturbed temperatures of 8-11°C. Examination of potential heat sources by analytical modelling reveals that increased ground surface temperatures and basements of buildings act as dominant drivers for the anthropogenic heat input into the groundwater. The factors are revealed to be case-specific and they may have pronounced local or regional effects. Typical local factors are for example buried district heating networks. In selected cities we find that the average urban heat flux is around one order of magnitude higher than the elevated ground heat flux due to recent climate change. Additionally, such as observed in Zurich, naturally controlled temperature variations can be substantial and they are shown to wash out anthropogenic thermal footprints.

  9. Thermal design of an electric motor using Particle Swarm Optimization

    International Nuclear Information System (INIS)

    Jandaud, P-O; Harmand, S; Fakes, M

    2012-01-01

    In this paper, flow inside an electric machine called starter-alternator is studied parametrically with CFD in order to be used by a thermal lumped model coupled to an optimization algorithm using Particle Swarm Optimization (PSO). In a first case, the geometrical parameters are symmetric allowing us to model only one side of the machine. The optimized thermal results are not conclusive. In a second case, all the parameters are independent. In this case, the flow is strongly influenced by the dissymmetry. Optimization results are this time a clear improvement compared to the original machine.

  10. VARIABILITY OF THE THERMAL CONTINENTALITY INDEX IN CENTRAL EUROPE

    Directory of Open Access Journals (Sweden)

    CIARANEK1 DOMINIKA

    2014-03-01

    Full Text Available The paper presents the spatial and temporal variability of thermal continentality in Central Europe. Gorczyński’s and Johansson-Ringleb’s formulae were used to derive the continentality index. The study also looked at the annual patterns of air temperature amplitude (A, a component of both of these formulae, and D; the difference between the average temperatures of autumn (Sep.-Nov. and spring (Mar.-May. Records of six weather stations representing the climate of Central Europe were included in the study covering the period 1775-2012 (Potsdam, Drezden, Prague, Vienna, Krakow, Debrecen. The highest continentality index was found in Debrecen and the lowest in Potsdam. The continentality index fluctuated with time with two pronounced dips at the turn of the 19th century and in the second half of the 20th century. The highest continentality index values were recorded during the 1930s and 1940s.

  11. Optimal joint scheduling of electrical and thermal appliances in a smart home environment

    International Nuclear Information System (INIS)

    Shirazi, Elham; Zakariazadeh, Alireza; Jadid, Shahram

    2015-01-01

    Highlights: • Thermal appliances are scheduled based on desired temperature and energy prices. • A discomfort index has been introduced within the home energy scheduling model. • Appliances are scheduled based on activity probability and desired options. • Starting probability depends on the social random factor and consumption behavior. - Abstract: With the development of home area network, residents have the opportunity to schedule their power usage in the home by themselves aiming at reducing electricity expenses. Moreover, as renewable energy sources are deployed in home, a home energy management system needs to consider both energy consumption and generation simultaneously to minimize the energy cost. In this paper, a smart home energy management model has been presented in which electrical and thermal appliances are jointly scheduled. The proposed method aims at minimizing the electricity cost of a residential customer by scheduling various type of appliances considering the residents consumption behavior, seasonal probability, social random factor, discomfort index and appliances starting probability functions. In this model, the home central controller receives the electricity price information, environmental factors data as well as the resident desired options in order to optimally schedule appliances including electrical and thermal. The scheduling approach is tested on a typical home including variety of home appliances, a small wind turbine, photovoltaic panel, combined heat and power unit, boiler and electrical and thermal storages over a 24-h period. The results show that the scheduling of different appliances can be reached simultaneously by using the proposed formulation. Moreover, simulation results evidenced that the proposed home energy management model exhibits a lower cost and, therefore, is more economical.

  12. Probe branes thermalization in external electric and magnetic fields

    International Nuclear Information System (INIS)

    Ali-Akbari, M.; Ebrahim, H.; Rezaei, Z.

    2014-01-01

    We study thermalization on rotating probe branes in AdS 5 ×S 5 background in the presence of constant external electric and magnetic fields. In the AdS/CFT framework this corresponds to thermalization in the flavour sector in field theory. The horizon appears on the worldvolume of the probe brane due to its rotation in one of the sphere directions. For both electric and magnetic fields the behaviour of the temperature is independent of the probe brane dimension. We also study the open string metric and the fluctuations of the probe brane in such a set-up. We show that the temperatures obtained from open string metric and observed by the fluctuations are larger than the one calculated from the induced metric

  13. Thermal and Electrical Investigation of Conductive Polylactic Acid Based Filaments

    Science.gov (United States)

    Dobre, R. A.; Marcu, A. E.; Drumea, A.; Vlădescu, M.

    2018-06-01

    Printed electronics gain momentum as the involved technologies become affordable. The ability to shape electrostatic dissipative materials in almost any form is useful. The idea to use a general-purpose 3D printer to manufacture the electrical interconnections for a circuit is very attractive. The advantage of using a 3D printed structure over other technologies are mainly the lower price, less requirements concerning storage and use conditions, and the capability to build thicker traces while maintaining flexibility. The main element allowing this to happen is a printing filament with conductive properties. The paper shows the experiments that were performed to determine the thermal and electrical properties of polylactic acid (PLA) based ESD dissipative filament. Quantitative results regarding the thermal behavior of the DC resistance and the variation of the equivalent parallel impedance model parameters (losses resistance, capacitance, impedance magnitude and phase angle) with frequency are shown.. Using these results, new applications like printed temperature sensors can be imagined.

  14. Integrated Vehicle Thermal Management - Combining Fluid Loops in Electric Drive Vehicles (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Rugh, J. P.

    2013-07-01

    Plug-in hybrid electric vehicles and electric vehicles have increased vehicle thermal management complexity, using separate coolant loop for advanced power electronics and electric motors. Additional thermal components result in higher costs. Multiple cooling loops lead to reduced range due to increased weight. Energy is required to meet thermal requirements. This presentation for the 2013 Annual Merit Review discusses integrated vehicle thermal management by combining fluid loops in electric drive vehicles.

  15. Prospects for solar thermal electricity generation - an introduction

    International Nuclear Information System (INIS)

    DeLaquil, P.

    1991-01-01

    The future potential for solar thermal electric power plants is quite significant. The size of the renewable energy resource base for the United States of America alone is almost 500 times its current primary energy consumption. Unfortunately, the levels of current utilization are quite small. Why have these technologies not made a larger contribution to today's market? The answer is that significant barriers still exist. (orig.)

  16. Macroeconomic impact of the Solar Thermal Electricity Industry in Spain

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-10-15

    In the last three years, Solar Thermal Electricity (STE) in Spain has grown significantly. Its weight within the renewables mix is becoming relevant, and even more so, its impact on economics, society, the environment, and reducing energy dependence. This report was carried out by Deloitte for Protermosolar to quantitatively and qualitatively evaluate the main macroeconomic variables derived from the development of this technology in Spain from 2008 to 2010, and forecast its possible future impact.

  17. Outdoor thermal and electrical characterisation of photovoltaic modules and systems

    OpenAIRE

    Herteleer, Bert

    2016-01-01

    Current and future investors in photovoltaic systems are interested in how well the system performs, and how predictable this is over the expected lifetime. To do so, models have been developed and measurements of photovoltaic systems have been done. This dissertation presents the outdoor measurement set-up that has been developed for thermal and electrical characterisation of photovoltaic modules and systems, aimed at measuring transient effects and changes. The main design decisions and ...

  18. Electrical stimulation vs thermal effects in a complex electromagnetic environment.

    Science.gov (United States)

    Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Sánchez, Miguel

    2009-08-01

    Studies linking exposure to low levels of radiofrequencies with adverse health effects, notwithstanding their present apparent inconsistency, have contributed to a steady improvement in the quality of evaluating that exposure. In complex electromagnetic environments, with a multitude of emissions of different frequencies acting simultaneously, knowledge of the spectral content is fundamental to evaluating human exposure to non-ionizing radiation. In the present work, we quantify the most significant spectral components in the frequency band 0.5-2200 MHz in an urban area. The measurements were made with a spectrum analyzer and monopole, biconical, and log-periodic antennas. Power density levels were calculated separately for the medium wave, short wave, and frequency modulation radio broadcasting bands, and for the television and GSM, DCS, and UMTS mobile telephony bands. The measured levels were compared with the ICNIRP reference levels for exposure to multiple frequency sources for thermal effects and electrical stimulation. The results showed the criterion limiting exposure on the basis of preventing electrical stimulation of peripheral nerves and muscles to be stricter (exposure quotient 24.7 10(-4)) than that based on thermal considerations (exposure quotient 0.16 10(-4)). The bands that contribute most to the latter are short wave, with 46.2%, and mobile telephony with 32.6% of the total exposure. In a complex electromagnetic environment, knowledge of the radiofrequency spectrum is essential in order to quantify the contribution of each type of emission to the public's exposure. It is also necessary to evaluate the electrical effects as well as the thermal effects because the criterion to limit exposure on the basis of the effect of the electrical stimulation of tissues is stricter than that based on thermal effects.

  19. Electrical stimulation vs thermal effects in a complex electromagnetic environment

    International Nuclear Information System (INIS)

    Paniagua, Jesus M.; Rufo, Montana; Jimenez, Antonio; Antolin, Alicia; Sanchez, Miguel

    2009-01-01

    Studies linking exposure to low levels of radiofrequencies with adverse health effects, notwithstanding their present apparent inconsistency, have contributed to a steady improvement in the quality of evaluating that exposure. In complex electromagnetic environments, with a multitude of emissions of different frequencies acting simultaneously, knowledge of the spectral content is fundamental to evaluating human exposure to non-ionizing radiation. In the present work, we quantify the most significant spectral components in the frequency band 0.5-2200 MHz in an urban area. The measurements were made with a spectrum analyzer and monopole, biconical, and log-periodic antennas. Power density levels were calculated separately for the medium wave, short wave, and frequency modulation radio broadcasting bands, and for the television and GSM, DCS, and UMTS mobile telephony bands. The measured levels were compared with the ICNIRP reference levels for exposure to multiple frequency sources for thermal effects and electrical stimulation. The results showed the criterion limiting exposure on the basis of preventing electrical stimulation of peripheral nerves and muscles to be stricter (exposure quotient 24.7 10 -4 ) than that based on thermal considerations (exposure quotient 0.16 10 -4 ). The bands that contribute most to the latter are short wave, with 46.2%, and mobile telephony with 32.6% of the total exposure. In a complex electromagnetic environment, knowledge of the radiofrequency spectrum is essential in order to quantify the contribution of each type of emission to the public's exposure. It is also necessary to evaluate the electrical effects as well as the thermal effects because the criterion to limit exposure on the basis of the effect of the electrical stimulation of tissues is stricter than that based on thermal effects.

  20. Understanding the thermal, mechanical and electrical properties of epoxy nanocomposites

    International Nuclear Information System (INIS)

    Sarathi, R.; Sahu, R.K.; Rajeshkumar, P.

    2007-01-01

    In the present work, the electrical, mechanical and thermal properties of epoxy nanocomposite materials were studied. The electrical insulation characteristics were analyzed through short time breakdown voltage test, accelerated electrical ageing test, and by tracking test. The breakdown voltage increases with increase in nano-clay content up to 5 wt%, under AC and DC voltages. The volume resistivity, permittivity and tan(δ) of the epoxy nanocomposites were measured. The Weibull studies indicate that addition of nanoclay upto 5 wt% enhances the characteristic life of epoxy nanocomposite insulation material. The tracking test results indicate that the tracking time is high with epoxy nanocomposites as compared to pure epoxy. Ageing studies were carried out to understand the surface characteristic variation through contact angle measurement. The hydrophobicity of the insulating material was analysed through contact angle measurement. The diffusion coefficients of the material with different percentage of clay in epoxy nanocomposites were calculated. The exfoliation characteristics in epoxy nanocomposites were analyzed through wide angle X-ray diffraction (WAXD) studies. The thermal behaviour of the epoxy nanocomposites was analyzed by carrying out thermo gravimetric-differential thermal analysis (TG-DTA) studies. Heat deflection temperature of the material was measured to understand the stability of the material for intermittent temperature variation. The dynamic mechanical analysis (DMA) results indicated that storage modulus of the material increases with small amount of clay in epoxy resin. The activation energy of the material was calculated from the DMA results

  1. Central receiver solar thermal power system, Phase 1. CDRL item 2. Pilot plant preliminary design report. Volume VI. Electrical power generation and master control subsystems and balance of plant

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The requirements, performance, and subsystem configuration for both the Commercial and Pilot Plant electrical power generation subsystems (EPGS) and balance of plants are presented. The EPGS for both the Commercial Plant and Pilot Plant make use of conventional, proven equipment consistent with good power plant design practices in order to minimize risk and maximize reliability. The basic EPGS cycle selected is a regenerative cycle that uses a single automatic admission, condensing, tandem-compound double-flow turbine. Specifications, performance data, drawings, and schematics are included. (WHK)

  2. Dynamic thermal characteristics of heat pipe via segmented thermal resistance model for electric vehicle battery cooling

    Science.gov (United States)

    Liu, Feifei; Lan, Fengchong; Chen, Jiqing

    2016-07-01

    Heat pipe cooling for battery thermal management systems (BTMSs) in electric vehicles (EVs) is growing due to its advantages of high cooling efficiency, compact structure and flexible geometry. Considering the transient conduction, phase change and uncertain thermal conditions in a heat pipe, it is challenging to obtain the dynamic thermal characteristics accurately in such complex heat and mass transfer process. In this paper, a ;segmented; thermal resistance model of a heat pipe is proposed based on thermal circuit method. The equivalent conductivities of different segments, viz. the evaporator and condenser of pipe, are used to determine their own thermal parameters and conditions integrated into the thermal model of battery for a complete three-dimensional (3D) computational fluid dynamics (CFD) simulation. The proposed ;segmented; model shows more precise than the ;non-segmented; model by the comparison of simulated and experimental temperature distribution and variation of an ultra-thin micro heat pipe (UMHP) battery pack, and has less calculation error to obtain dynamic thermal behavior for exact thermal design, management and control of heat pipe BTMSs. Using the ;segmented; model, the cooling effect of the UMHP pack with different natural/forced convection and arrangements is predicted, and the results correspond well to the tests.

  3. Electrically and Thermally Conducting Nanocomposites for Electronic Applications

    Directory of Open Access Journals (Sweden)

    Daryl Santos

    2010-02-01

    Full Text Available Nanocomposites made up of polymer matrices and carbon nanotubes are a class of advanced materials with great application potential in electronics packaging. Nanocomposites with carbon nanotubes as fillers have been designed with the aim of exploiting the high thermal, electrical and mechanical properties characteristic of carbon nanotubes. Heat dissipation in electronic devices requires interface materials with high thermal conductivity. Here, current developments and challenges in the application of nanotubes as fillers in polymer matrices are explored. The blending together of nanotubes and polymers result in what are known as nanocomposites. Among the most pressing current issues related to nanocomposite fabrication are (i dispersion of carbon nanotubes in the polymer host, (ii carbon nanotube-polymer interaction and the nature of the interface, and (iii alignment of carbon nanotubes in a polymer matrix. These issues are believed to be directly related to the electrical and thermal performance of nanocomposites. The recent progress in the fabrication of nanocomposites with carbon nanotubes as fillers and their potential application in electronics packaging as thermal interface materials is also reported.

  4. Thermal Management and Reliability of Power Electronics and Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, Sreekant

    2016-08-03

    Increasing the number of electric-drive vehicles (EDVs) on America's roads has been identified as a strategy with near-term potential for dramatically decreasing the nation's dependence on oil -- by the U.S. Department of Energy, the federal cross-agency EV-Everywhere Challenge, and the automotive industry. Mass-market deployment will rely on meeting aggressive technical targets, including improved efficiency and reduced size, weight, and cost. Many of these advances will depend on optimization of thermal management. Effective thermal management is critical to improving the performance and ensuring the reliability of EDVs. Efficient heat removal makes higher power densities and lower operating temperatures possible, and in turn enables cost and size reductions. The National Renewable Energy Laboratory (NREL), along with DOE and industry partners is working to develop cost-effective thermal management solutions to increase device and component power densities. In this presentation, the activities in recent years related to thermal management and reliability of automotive power electronics and electric machines will be presented.

  5. Thermal Management and Reliability of Power Electronics and Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, Sreekant

    2016-06-13

    Increasing the number of electric-drive vehicles (EDVs) on America's roads has been identified as a strategy with near-term potential for dramatically decreasing the nation's dependence on oil - by the U.S. Department of Energy, the federal cross-agency EV-Everywhere Challenge, and the automotive industry. Mass-market deployment will rely on meeting aggressive technical targets, including improved efficiency and reduced size, weight, and cost. Many of these advances will depend on optimization of thermal management. Effective thermal management is critical to improving the performance and ensuring the reliability of EDVs. Efficient heat removal makes higher power densities and lower operating temperatures possible, and in turn enables cost and size reductions. The National Renewable Energy Laboratory (NREL), along with DOE and industry partners is working to develop cost-effective thermal management solutions to increase device and component power densities. In this presentation, the activities in recent years related to thermal management and reliability of automotive power electronics and electric machines are presented.

  6. Shallow Crustal Thermal Structures of Central Taiwan Foothills Region

    Directory of Open Access Journals (Sweden)

    Shao-Kai Wu

    2013-01-01

    Full Text Available Crustal thermal structures are closely related to metamorphism, rock rheology, exhumation processes, hydrocarbon maturation levels, frictional faulting and other processes. Drilling is the most direct way to access the temperature fields in the shallow crust. However, a regional drilling program for geological investigation is usually very expensive. Recently, a large-scale in-situ investigation program in the Western Foothills of Central Taiwan was carried out, providing a rare opportunity to conduct heat flow measurements in this region where there are debates as to whether previous measured heat flows are representative of the thermal state in this region. We successfully collected 28 geothermal gradients from these wells and converted them into heat flows. The new heat flow dataset is consistent with previous heat flows, which shows that the thermal structures of Central Taiwan are different from that of other subduction accretionary prisms. We then combine all the available heat flow information to analyze the frictional parameters of the Chelungpu fault zone that ruptured during the 1999, Chi-Chi, Taiwan, earthquake. The heat flow dataset gave consistent results compared with the frictional parameters derived from another independent study that used cores recovered from the Chelungpu fault zone at depth. This study also shows that it is suitable for using heat-flow data obtained from shallow subsurface to constrain thrusting faulting parameters, similar to what had been done for the strike-slip San Andreas Fault in California. Additional fieldworks are planned to study heat flows in other mountainous regions of Taiwan for more advanced geodynamic modeling efforts.

  7. Study of the electrical and thermal performances of photovoltaic thermal collector-compound parabolic concentrated

    Directory of Open Access Journals (Sweden)

    Ahed Hameed Jaaz

    2018-06-01

    Full Text Available The importance of utilizing the solar energy as a very suitable source among multi-source approaches to replace the conventional energy is on the rise in the last four decades. The invention of the photovoltaic module (PV could be the corner stone in this process. However, the limited amount of energy obtained from PV was and still the main challenge of full utilization of the solar energy. In this paper, the use of the compound parabolic concentrator (CPC along with the thermal photovoltaic module (PVT where the cooling process of the CPC is conducted using a novel technique of water jet impingement has applied experimentally and physically tested. The test includes the effect of water jet impingement on the total power, electrical efficiency, thermal efficiency, and total efficiency on CPC-PVT system. The cooling process at the maximum irradiation by water jet impingement resulted in improving the electrical efficiency by 7%, total output power by 31% and the thermal efficiency by 81%. These results outperform the recent highest results recorded by the most recent work. Keywords: Photovoltaic thermal collectors, Electrical performance, Thermal performance, Compound parabolic concentrator, Jet impingement

  8. An electrical method for the measurement of the thermal and electrical conductivity of reduced graphene oxide nanostructures.

    Science.gov (United States)

    Schwamb, Timo; Burg, Brian R; Schirmer, Niklas C; Poulikakos, Dimos

    2009-10-07

    This paper introduces an electrical four-point measurement method enabling thermal and electrical conductivity measurements of nanoscale materials. The method was applied to determine the thermal and electrical conductivity of reduced graphene oxide flakes. The dielectrophoretically deposited samples exhibited thermal conductivities in the range of 0.14-2.87 W m(-1) K(-1) and electrical conductivities in the range of 6.2 x 10(2)-6.2 x 10(3) Omega(-1) m(-1). The measured properties of each flake were found to be dependent on the duration of the thermal reduction and are in this sense controllable.

  9. Commercialization of new energy technologies. Appendix A. Case study 1: central station electric power generation technologies

    International Nuclear Information System (INIS)

    1976-06-01

    The results of a survey on Technologies for Central Power Generation are presented. The central power generation technologies selected for consideration were: fusion; breeder reactors; solar electric (thermal); geothermal; and magnetohydrodynamics. The responses of industry executives who make key investment decisions concerning new energy technologies and who to identify the problems faced in the development and commercialization of new energy systems are presented. Evaluation of these responses led to the following recommendations: increase industry input into the R, D and D planning process; establish and advocate priorities for new technologies based on detailed analysis of a technology's value in terms of overall national goals; create a mechanism for a joint ERDA/industry appraisal of priorities and programs; increase level of federal funding or subsidy of new technology demonstrations; and focus the activities of the national laboratories on basic research and very early product development; and emphasize industry involvement in systems development

  10. Transmutor demo unit and thermal into electrical energy transformation problems

    International Nuclear Information System (INIS)

    Matal, O.; Fiedler, J.

    1999-01-01

    In the three circuits layout of the transmutor the heat is transferred from the primary through the secondary circuits by a favourable heat carrier into the tertiary circuit where the thermal into electrical energy transformation in turbo-generator comes into force. Properties as well as parameters of the heat carrier in the secondary circuit affect basically both the conceptual layout of the tertiary circuit and consequently investments costs for its realization and the effectiveness of the transformation of thermal into electrical energy. For several heat carriers considered for the transmutor secondary circuit particular tertiary circuit concepts for the demonstration transmutor unit of approx. 15 W thermal power rate are analyzed, layout features and possibilities of turbogenerator selection are commented and investment costs as well as effectiveness of thermal into electrical energy transformation are estimated. Some of the results are as follows: (i) Heat carrier properties influence thermodynamics of the TDU water/steam cycle substantially. One of the dominant parameters is the melting (freezing) temperature of the heat carrier. (ii) Heat carrier properties influence investment costs of components of the TDU tertiary circuit substantially. Dominantly influenced are costs of the steam generator, steam turbine and high pressure regeneration system. (iii) If the heat carrier has to be a molten salt than a salt with a low melting temperature is recommended to be selected, for example KHF2. (iv) Eutectic alloy Pb-Bi as the heat carrier serves changes to design the TDU with efficient thermodynamics, with acceptable low investment costs of the tertiary as well as secondary circuit components and with an acceptable level of the nuclear safety

  11. Solar thermal electric power generation - an attractive option for Pakistan

    International Nuclear Information System (INIS)

    Khan, N.A

    1999-01-01

    Solar Thermal Energy is being successfully used for production of electricity in few developed countries for more than 10 years. In solar Electric Generating Systems high temperature is generated by concentrating solar energy on black absorber pipe in evacuated glass tubes. This heat is absorbed and transported with the help of high temperature oil in to highly insulated heat exchanger storage tanks. They are subsequently used to produce steam that generates power through steam turbines as in standard thermal power plants. Various components involved in Solar thermal field have been developed at the Solar Systems Laboratory of College of EME, NUST Rawalpindi. It is considered as a cost effective alternate for power generation. The research has been partially sponsored by Ministry of Science and Technology under its Public Sector Development Program (PSDP) in (1996-1998). Parabolic mirror design, fabrication, polishing, installation, solar tracking, absorber pipe, glass tubes, steam generation al have been developed. This paper will cover the details of indigenous technological break through made in this direction. (author)

  12. On the possibility of generation of cold and additional electric energy at thermal power stations

    Science.gov (United States)

    Klimenko, A. V.; Agababov, V. S.; Borisova, P. N.

    2017-06-01

    A layout of a cogeneration plant for centralized supply of the users with electricity and cold (ECCG plant) is presented. The basic components of the plant are an expander-generator unit (EGU) and a vapor-compression thermotransformer (VCTT). At the natural-gas-pressure-reducing stations, viz., gas-distribution stations and gas-control units, the plant is connected in parallel to a throttler and replaces the latter completely or partially. The plant operates using only the energy of the natural gas flow without burning the gas; therefore, it can be classified as a fuelless installation. The authors compare the thermodynamic efficiencies of a centralized cold supply system based on the proposed plant integrated into the thermal power station scheme and a decentralized cold supply system in which the cold is generated by electrically driven vapor-compression thermotransformers installed on the user's premises. To perform comparative analysis, the exergy efficiency was taken as the criterion since in one of the systems under investigation the electricity and the cold are generated, which are energies of different kinds. It is shown that the thermodynamic efficiency of the power supply using the proposed plant proves to be higher within the entire range of the parameters under consideration. The article presents the results of investigating the impact of the gas heating temperature upstream from the expander on the electric power of the plant, its total cooling capacity, and the cooling capacities of the heat exchangers installed downstream from the EGU and the evaporator of the VCTT. The results of calculations are discussed that show that the cold generated at the gas-control unit of a powerful thermal power station can be used for the centralized supply of the cold to the ventilation and conditioning systems of both the buildings of the power station and the neighboring dwelling houses, schools, and public facilities during the summer season.

  13. Electric vehicles batteries thermal management systems employing phase change materials

    Science.gov (United States)

    Ianniciello, Lucia; Biwolé, Pascal Henry; Achard, Patrick

    2018-02-01

    Battery thermal management is necessary for electric vehicles (EVs), especially for Li-ion batteries, due to the heat dissipation effects on those batteries. Usually, air or coolant circuits are employed as thermal management systems in Li-ion batteries. However, those systems are expensive in terms of investment and operating costs. Phase change materials (PCMs) may represent an alternative which could be cheaper and easier to operate. In fact, PCMs can be used as passive or semi-passive systems, enabling the global system to sustain near-autonomous operations. This article presents the previous developments introducing PCMs for EVs battery cooling. Different systems are reviewed and solutions are proposed to enhance PCMs efficiency in those systems.

  14. High-precision thermal and electrical characterization of thermoelectric modules

    Science.gov (United States)

    Kolodner, Paul

    2014-05-01

    This paper describes an apparatus for performing high-precision electrical and thermal characterization of thermoelectric modules (TEMs). The apparatus is calibrated for operation between 20 °C and 80 °C and is normally used for measurements of heat currents in the range 0-10 W. Precision thermometry based on miniature thermistor probes enables an absolute temperature accuracy of better than 0.010 °C. The use of vacuum isolation, thermal guarding, and radiation shielding, augmented by a careful accounting of stray heat leaks and uncertainties, allows the heat current through the TEM under test to be determined with a precision of a few mW. The fractional precision of all measured parameters is approximately 0.1%.

  15. Physical factors affecting the electrically assisted thermal bitumen recovery

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, I.I.; Torres, J.-A.; Kamp, A.M. [CHLOE, University of Pau (France); Corre, B. [CSTJF, Total (France)

    2011-07-01

    In the heavy oil industry, thermal processes are used to enhance oil recovery by increasing the reservoir temperature which results in better oil mobility. Low frequency heating (LFH) is a technology using electrical conductivity of connate water to propagate current between electrodes, thus generating heat in the reservoir through the Joule effect. During the preheating and production periods, many physical factors may affect the LFH process and the aim of this study was to determine which factors affect the process and how, using a particular pattern of electrodes. Simulations were conducted using the CMG Stars reservoir simulator under different configurations, conditions and parameters. Important physical properties and operational conditions affecting the LFH process were determined and results showed that convection heat, bulk electrical conductivity and power distribution can be improved by salt water circulation. This paper highlighted the physical factors affecting LFH efficiency and these findings will be useful for future process design.

  16. Electrical and thermal transport properties of uranium and plutonium carbides

    International Nuclear Information System (INIS)

    Lewis, H.D.; Kerrisk, J.F.

    1976-09-01

    Contributions of many authors are outlined with respect to the experimental measurement methods used and characteristics of the sample materials. Discussions treat the qualitative effects of sample material composition; oxygen, nitrogen, and nickel concentrations; porosity; microstructural variations; and the variability in transport property values obtained by the various investigators. Temperature-dependent values are suggested for the electrical resistivities and thermal conductivities of selected carbide compositions based on a comparative evaluation of the available data and the effects of variation in the characteristics of sample materials

  17. Low-cost distributed solar-thermal-electric power generation

    Science.gov (United States)

    Der Minassians, Artin; Aschenbach, Konrad H.; Sanders, Seth R.

    2004-01-01

    Due to their high relative cost, solar electric energy systems have yet to be exploited on a widespread basis. It is believed in the energy community that a technology similar to photovoltaic (PV), but offered at about $1/W would lead to widespread deployment at residential and commercial sites. This paper addresses the investigation and feasibility study of a low-cost solar thermal electricity generation technology, suitable for distributed deployment. Specifically, we discuss a system based on nonimaging solar concentrators, integrated with free-piston Stirling engine devices incorporating integrated electric generation. We target concentrator-collector operation at moderate temperatures, in the range of 125°C to 150°C. This temperature is consistent with use of optical concentrators with concentration ratios on the order of 1-2. These low ratio concentrators admit wide angles of radiation acceptance and are thus compatible with no diurnal tracking, and no or only a few seasonal adjustments. Thus, costs and reliability hazards associated with tracking hardware systems are avoided. Further, we note that in the intended application, there is no shortage of incident solar energy, but rather it is the capital cost of the solar-electric system that is most precious. Thus, we outline a strategy for exploiting solar resources in a cost constrained manner. The paper outlines design issues, and a specific design for an appropriately dimensioned free-piston Stirling engine. Only standard low-cost materials and manufacturing methods are required to realize such a machine.

  18. Development of Tailorable Electrically Conductive Thermal Control Material Systems

    Science.gov (United States)

    Deshpande, M. S.; Harada, Y.

    1997-01-01

    The optical characteristics of surfaces on spacecraft are fundamental parameters in controlling its temperature. Passive thermal control coatings with designed solar absorptance and infrared emittance properties have been developed and have been in use for some time. In this total space environment, the coating must be stable and maintain its desired optical properties as well as mechanical properties for the course of the mission lifetime. The mission lifetimes are increasing and in our quest to save weight, newer substrates are being integrated which limit electrical grounding schemes. All of this has added to already existing concerns about spacecraft charging and related spacecraft failures or operational failures. The concern is even greater for thermal control surfaces that are very large. One way of alleviating such concerns is to design new thermal control material systems (TCMS) that can help to mitigate charging via providing charge leakage paths. The objective of this program was to develop two types of passive electrically conductive TCMS. The first was a highly absorbing/emitting black surface and the second was a low (alpha(sub s)/epsilon(sub N)) type white surface. The surface resistance goals for the black absorber was 10(exp 4) to 10(exp 9) Omega/square, and for the white surfaces it was 10(exp 6) to 10(exp 10) Omega/square. Several material system concepts were suggested and evaluated for space environment stability and electrical performance characterization. Our efforts in designing and evaluating these material systems have resulted in several developments. New concepts, pigments and binders have been developed to provide new engineering quality TCMS. Some of these have already found application on space hardware, some are waiting to be recognized by thermal designers, and some require further detailed studies to become state-of-the-art for future space hardware and space structures. Our studies on baseline state-of-the-art materials and

  19. Parametric studies and optimisation of pumped thermal electricity storage

    International Nuclear Information System (INIS)

    McTigue, Joshua D.; White, Alexander J.; Markides, Christos N.

    2015-01-01

    Highlights: • PTES is modelled by cycle analysis and a Schumann-style model of the thermal stores. • Optimised trade-off surfaces show a flat efficiency vs. energy density profile. • Overall roundtrip efficiencies of around 70% are not inconceivable. - Abstract: Several of the emerging technologies for electricity storage are based on some form of thermal energy storage (TES). Examples include liquid air energy storage, pumped heat energy storage and, at least in part, advanced adiabatic compressed air energy storage. Compared to other large-scale storage methods, TES benefits from relatively high energy densities, which should translate into a low cost per MW h of storage capacity and a small installation footprint. TES is also free from the geographic constraints that apply to hydro storage schemes. TES concepts for electricity storage rely on either a heat pump or refrigeration cycle during the charging phase to create a hot or a cold storage space (the thermal stores), or in some cases both. During discharge, the thermal stores are depleted by reversing the cycle such that it acts as a heat engine. The present paper is concerned with a form of TES that has both hot and cold packed-bed thermal stores, and for which the heat pump and heat engine are based on a reciprocating Joule cycle, with argon as the working fluid. A thermodynamic analysis is presented based on traditional cycle calculations coupled with a Schumann-style model of the packed beds. Particular attention is paid to the various loss-generating mechanisms and their effect on roundtrip efficiency and storage density. A parametric study is first presented that examines the sensitivity of results to assumed values of the various loss factors and demonstrates the rather complex influence of the numerous design variables. Results of an optimisation study are then given in the form of trade-off surfaces for roundtrip efficiency, energy density and power density. The optimised designs show a

  20. Electrical properties and thermal expansion of strontium aluminates

    Energy Technology Data Exchange (ETDEWEB)

    Zakharchuk, K.V. [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Yaremchenko, A.A., E-mail: ayaremchenko@ua.pt [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Fagg, D.P. [TEMA-NRD, Mechanical Engineering Department, University of Aveiro, 3810-193 Aveiro (Portugal)

    2014-11-15

    Highlights: • Sr{sub 3}Al{sub 2}O{sub 6}, SrAl{sub 2}O{sub 4} and Sr{sub 4}Al{sub 14}O{sub 25} ceramics are semiconductors. • Electrical conductivity is as low as 10{sup −6}−4×10{sup −5} S/cm at 1273 K in dry air. • SrAl{sub 2}O{sub 4} is a mixed conductor with predominant ionic conductivity. • Sr{sub 3}Al{sub 2}O{sub 6} shows significant contribution of protonic transport in wet atmospheres. • Average TECs vary in the range (8.5–11.1)×10{sup −6} K{sup −1} and are p(O{sub 2})-independent. - Abstract: Strontium aluminate ceramics, including Sr{sub 3}Al{sub 2}O{sub 6}, SrAl{sub 2}O{sub 4} and Sr{sub 4}Al{sub 14}O{sub 25}, synthesized by glycine–nitrate combustion and sintered at 1773 K in air, were characterized by thermal analysis, dilatometry and electrical measurements in controlled atmospheres. All studied strontium aluminates are semiconductors with electrical conductivities as low as 10{sup −6}−4×10{sup −5} S/cm at 1273 K in dry air. Electrical measurements in controlled atmospheres in combination with ion transference number determination demonstrated that SrAl{sub 2}O{sub 4} is a mixed conductor with predominant ionic conductivity and increasing n-type and p-type electronic contributions under highly reducing and oxidizing conditions, respectively. While the behavior of electrical conductivity of Sr{sub 3}Al{sub 2}O{sub 6} in dry atmospheres was qualitatively similar to that of SrAl{sub 2}O{sub 4}, a significant increase of conductivity in wet atmospheres was attributed to a protonic contribution to electrical conduction, in correlation with thermogravimetric data and the tendency of this material to form a hydrogarnet at low temperatures. The average thermal expansion coefficients of strontium aluminates, (8.5–11.1)×10{sup −6} K{sup −1} at 333–1373 K, increase with increasing strontium content in the sequence Sr{sub 4}Al{sub 14}O{sub 25} < SrAl{sub 2}O{sub 4} < Sr{sub 3}Al{sub 2}O{sub 6} and are essentially

  1. Central Receiver Solar Thermal Power System, Phase 1. CDRL Item 2. Pilot Plant preliminary design report. Volume III, Book 1. Collector subsystem

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The central receiver system consists of a field of heliostats, a central receiver, a thermal storage unit, an electrical power generation system, and balance of plant. This volume discusses the collector field geometry, requirements and configuration. The development of the collector system and subsystems are discussed and the selection rationale outlined. System safety and availability are covered. Finally, the plans for collector portion of the central receiver system are reviewed.

  2. Simultaneous Thermal and Gamma Radiation Aging of Electrical Cable Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Fifield, Leonard S.

    2018-04-11

    The polymers used for insulation in nuclear power plant electrical cables are susceptible to aging during long term operation. Elevated temperature is the primary contributor to changes in polymer structure that result loss of mechanical and electrical properties, but gamma radiation is also a significant source of degradation for polymers used within relevant plant locations. Despite many years of polymer degradation research, the combined effects of simultaneous exposure to thermal and radiation stress are not well understood. As nuclear operators contemplate and prepare for extended operations beyond initial license periods, a predictive understanding of exposure-based cable material degradation is becoming an increasingly important input to safety, licensing, operations and economic decisions. We are focusing on carefully-controlled simultaneous thermal and gamma radiation accelerating aging and characterization of the most common nuclear cable polymers to understand the relative contributions of temperature, time, dose and dose rate to changes in cable polymer material structure and properties. Improved understanding of cable performance in long term operation will help support continued sustainable nuclear power generation.

  3. The Thermal Electrical Conductivity Probe (TECP) for Phoenix

    Science.gov (United States)

    Zent, Aaron P.; Hecht, Michael H.; Cobos, Doug R.; Campbell, Gaylon S.; Campbell, Colin S.; Cardell, Greg; Foote, Marc C.; Wood, Stephen E.; Mehta, Manish

    2009-01-01

    The Thermal and Electrical Conductivity Probe (TECP) is a component of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) payload on the Phoenix Lander. TECP will measure the temperature, thermal conductivity and volumetric heat capacity of the regolith. It will also detect and quantify the population of mobile H2O molecules in the regolith, if any, throughout the polar summer, by measuring the electrical conductivity of the regolith, as well as the dielectric permittivity. In the vapor phase, TECP is capable of measuring the atmospheric H2O vapor abundance, as well as augment the wind velocity measurements from the meteorology instrumentation. TECP is mounted near the end of the 2.3 m Robotic Arm, and can be placed either in the regolith material or held aloft in the atmosphere. This paper describes the development and calibration of the TECP. In addition, substantial characterization of the instrument has been conducted to identify behavioral characteristics that might affect landed surface operations. The greatest potential issue identified in characterization tests is the extraordinary sensitivity of the TECP to placement. Small gaps alter the contact between the TECP and regolith, complicating data interpretation. Testing with the Phoenix Robotic Arm identified mitigation techniques that will be implemented during flight. A flight model of the instrument was also field tested in the Antarctic Dry Valleys during the 2007-2008 International Polar year. 2

  4. Thermal modeling of secondary lithium batteries for electric vehicle/hybrid electric vehicle applications

    Science.gov (United States)

    Al-Hallaj, Said; Selman, J. R.

    A major obstacle to the development of commercially successful electric vehicles (EV) or hybrid electric vehicles (HEV) is the lack of a suitably sized battery. Lithium ion batteries are viewed as the solution if only they could be "scaled-up safely", i.e. if thermal management problems could be overcome so the batteries could be designed and manufactured in much larger sizes than the commercially available near-2-Ah cells. Here, we review a novel thermal management system using phase-change material (PCM). A prototype of this PCM-based system is presently being manufactured. A PCM-based system has never been tested before with lithium-ion (Li-ion) batteries and battery packs, although its mode of operation is exceptionally well suited for the cell chemistry of the most common commercially available Li-ion batteries. The thermal management system described here is intended specifically for EV/HEV applications. It has a high potential for providing effective thermal management without introducing moving components. Thereby, the performance of EV/HEV batteries may be improved without complicating the system design and incurring major additional cost, as is the case with "active" cooling systems requiring air or liquid circulation.

  5. A review on battery thermal management in electric vehicle application

    Science.gov (United States)

    Xia, Guodong; Cao, Lei; Bi, Guanglong

    2017-11-01

    The global issues of energy crisis and air pollution have offered a great opportunity to develop electric vehicles. However, so far, cycle life of power battery, environment adaptability, driving range and charging time seems far to compare with the level of traditional vehicles with internal combustion engine. Effective battery thermal management (BTM) is absolutely essential to relieve this situation. This paper reviews the existing literature from two levels that are cell level and battery module level. For single battery, specific attention is paid to three important processes which are heat generation, heat transport, and heat dissipation. For large format cell, multi-scale multi-dimensional coupled models have been developed. This will facilitate the investigation on factors, such as local irreversible heat generation, thermal resistance, current distribution, etc., that account for intrinsic temperature gradients existing in cell. For battery module based on air and liquid cooling, series, series-parallel and parallel cooling configurations are discussed. Liquid cooling strategies, especially direct liquid cooling strategies, are reviewed and they may advance the battery thermal management system to a new generation.

  6. Electrical properties of pressure quenched silicon by thermal spraying

    International Nuclear Information System (INIS)

    Tan, S.Y.; Gambino, R.J.; Sampath, S.; Herman, H.

    2007-01-01

    High velocity thermal spray deposition of polycrystalline silicon film onto single crystal substrates, yields metastable high pressure forms of silicon in nanocrystalline form within the deposit. The phases observed in the deposit include hexagonal diamond-Si, R-8, BC-8 and Si-IX. The peculiar attribute of this transformation is that it occurs only on orientation silicon substrate. The silicon deposits containing the high pressure phases display a substantially higher electrical conductivity. The resistivity profile of the silicon deposit containing shock induced metastable silicon phases identified by X-ray diffraction patterns. The density of the pressure induced polymorphic silicon is higher at deposit/substrate interface. A modified two-layer model is presented to explain the resistivity of the deposit impacted by the pressure induced polymorphic silicon generated by the thermal spraying process. The pressure quenched silicon deposits on the p - silicon substrate, with or without metastable phases, display the barrier potential of about 0.72 eV. The measured hall mobility value of pressure quenched silicon deposits is in the range of polycrystalline silicon. The significance of this work lies in the fact that the versatility of thermal spray may enable applications of these high pressure forms of silicon

  7. Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

    Science.gov (United States)

    Grandjean, Thomas; Barai, Anup; Hosseinzadeh, Elham; Guo, Yue; McGordon, Andrew; Marco, James

    2017-08-01

    It is crucial to maintain temperature homogeneity in lithium ion batteries in order to prevent adverse voltage distributions and differential ageing within the cell. As such, the thermal behaviour of a large-format 20 Ah lithium iron phosphate pouch cell is investigated over a wide range of ambient temperatures and C rates during both charging and discharging. Whilst previous studies have only considered one surface, this article presents experimental results, which characterise both surfaces of the cell exposed to similar thermal media and boundary conditions, allowing for thermal gradients in-plane and perpendicular to the stack to be quantified. Temperature gradients, caused by self-heating, are found to increase with increasing C rate and decreasing temperature to such an extent that 13.4 ± 0.7% capacity can be extracted using a 10C discharge compared to a 0.5C discharge, both at -10 °C ambient temperature. The former condition causes an 18.8 ± 1.1 °C in plane gradient and a 19.7 ± 0.8 °C thermal gradient perpendicular to the stack, which results in large current density distributions and local state of charge differences within the cell. The implications of these thermal and electrical inhomogeneities on ageing and battery pack design for the automotive industry are discussed.

  8. Study of the electrical and thermal performances of photovoltaic thermal collector-compound parabolic concentrated

    Science.gov (United States)

    Jaaz, Ahed Hameed; Sopian, Kamaruzzaman; Gaaz, Tayser Sumer

    2018-06-01

    The importance of utilizing the solar energy as a very suitable source among multi-source approaches to replace the conventional energy is on the rise in the last four decades. The invention of the photovoltaic module (PV) could be the corner stone in this process. However, the limited amount of energy obtained from PV was and still the main challenge of full utilization of the solar energy. In this paper, the use of the compound parabolic concentrator (CPC) along with the thermal photovoltaic module (PVT) where the cooling process of the CPC is conducted using a novel technique of water jet impingement has applied experimentally and physically tested. The test includes the effect of water jet impingement on the total power, electrical efficiency, thermal efficiency, and total efficiency on CPC-PVT system. The cooling process at the maximum irradiation by water jet impingement resulted in improving the electrical efficiency by 7%, total output power by 31% and the thermal efficiency by 81%. These results outperform the recent highest results recorded by the most recent work.

  9. Improvement of Thermal and Electrical Conductivity of Epoxy/boron Nitride/silver Nanoparticle Composite

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seungyong; Lim, Soonho [Korea Institute of Science and Technology, Wanju (Korea, Republic of)

    2017-06-15

    In this study, we investigated the effect of BN (boron nitride) on the thermal and the electrical conductivity of composites. In case of epoxy/BN composites, the thermal conductivity was increased as the BN contents were increased. Epoxy/AgNP (Ag nanoparticle) nanocomposites exhibited a slight change of thermal conductivity and showed a electrical percolation threshold at 20 vol% of Ag nanoparticles. At the fixed Ag nanoparticle content below the electrical percolation threshold, increasing the amount of BN enhanced the electrical conductivity as well as thermal conductivity for the epoxy/AgNP/BN composites.

  10. Thermal to Electric Energy Conversion for Cyclic Heat Loads

    Science.gov (United States)

    Whitehead, Benjamin E.

    Today, we find cyclic heat loads almost everywhere. When we drive our cars, the engines heat up while we are driving and cool while parked. Processors heat while the computer is in use at the office and cool when idle at night. The sun heats the earth during the day and the earth radiates that heat into space at night. With modern technology, we have access to a number of methods to take that heat and convert it into electricity, but, before selecting one, we need to identify the parameters that inform decision making. The majority of the parameters for most systems include duty cycle, total cost, weight, size, thermal efficiency, and electrical efficiency. However, the importance of each of these will depend on the application. Size and weight take priority in a handheld device, while efficiency dominates in a power plant, and duty cycle is likely to dominate in highly demanding heat pump applications. Over the past decade, developments in semiconductor technology has led to the creation of the thermoelectric generator. With no moving parts and a nearly endlessly scalable nature, these generators present interesting opportunities for taking advantage of any source of waste heat. However, these generators are typically only capable of 5-8% efficiency from conversion of thermal to electric energy. [1]. Similarly, advancements in photovoltaic cells has led to the development of thermophotovoltaics. By heating an emitter to a temperature so it radiates light, a thermophotovoltaic cell then converts that light into electricity. By selecting materials that emit light in the optimal ranges of the appropriate photovoltaic cells, thermophotovoltaic systems can potentially exceed the current maximum of 10% efficiency. [2]. By pressurizing certain metal powders with hydrogen, hydrogen can be bound to the metal, creating a metal hydride, from which hydrogen can be later re-extracted under the correct pressure and temperature conditions. Since this hydriding reaction is

  11. Energy expansion planning by considering electrical and thermal expansion simultaneously

    International Nuclear Information System (INIS)

    Abbasi, Ali Reza; Seifi, Ali Reza

    2014-01-01

    Highlights: • This paper focused on the expansion planning optimization of energy systems. • Employing two form of energy: the expansion of electrical and thermal energies. • The main objective is to minimize the costs. • A new Modified Honey Bee Mating Optimization (MHBMO) algorithm is applied. - Abstract: This study focused on the expansion planning optimization of energy systems employing two forms of energy: the expansion of electrical and thermal energies simultaneously. The main objective of this investigation is confirming network adequacy by adding new equipment to the network, over a given planning horizon. The main objective of the energy expansion planning (EEP) is to minimize the real energy loss, voltage deviation and the total cost of installation equipments. Since the objectives are different and incommensurable, it is difficult to solve the problem by the conventional approaches that may optimize a single objective. So, the meta-heuristic algorithm is applied to this problem. Here, Honey Bee Mating Optimization algorithm (HBMO) as a new evolutionary optimization algorithm is utilized. In order to improve the total ability of HBMO for the global search and exploration, a new modification process is suggested such a way that the algorithm will search the total search space globally. Also, regarding the uncertainties of the new complicated energy systems, in this paper for the first time, the EEP problem is investigated in a stochastic environment by the use of probabilistic load flow technique based on Point Estimate Method (PEM). In order to evaluate the feasibility and effectiveness of the proposed algorithm, two modified test systems are used as case studies

  12. Survey of solar thermal energy storage subsystems for thermal/electric applications

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C. L.

    1978-08-01

    A survey of the current technology and estimated costs of subsystems for storing the thermal energy produced by solar collectors is presented. The systems considered were capable of producing both electricity and space conditioning for three types of loads: a single-family detached residence, an apartment complex of 100 units, and a city of 30,000 residents, containing both single-family residences and apartments. Collector temperatures will be in four ranges: (1) 100 to 250/sup 0/F (used for space heating and single-cycle air conditioners and organic Rankine low-temperature turbines); (2) 300 to 400/sup 0/F (used for dual-cycle air conditioners and low-temperature turbines); (3) 400 to 600/sup 0/F (using fluids from parabolic trough collectors to run Rankine turbines); (4) 800 to 1000/sup 0/F (using fluids from heliostats to run closed-cycle gas turbines and steam Rankine turbines). The solar thermal energy subsystems will require from 60 to 36 x 10/sup 5/ kWhr (2.05 x 10/sup 5/ to 1.23 x 10/sup 10/ Btu) of thermal storage capacity. In addition to sensible heat and latent heat storage materials, several other media were investigated as potential thermal energy storage materials, including the clathrate and semiclathrate hydrates, various metal hydrides, and heat storage based on inorganic chemical reactions.

  13. Advanced Thermal Storage for Central Receivers with Supercritical Coolants

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Bruce D.

    2010-06-15

    The principal objective of the study is to determine if supercritical heat transport fluids in a central receiver power plant, in combination with ceramic thermocline storage systems, offer a reduction in levelized energy cost over a baseline nitrate salt concept. The baseline concept uses a nitrate salt receiver, two-tank (hot and cold) nitrate salt thermal storage, and a subcritical Rankine cycle. A total of 6 plant designs were analyzed, as follows: Plant Designation Receiver Fluid Thermal Storage Rankine Cycle Subcritical nitrate salt Nitrate salt Two tank nitrate salt Subcritical Supercritical nitrate salt Nitrate salt Two tank nitrate salt Supercritical Low temperature H2O Supercritical H2O Two tank nitrate salt Supercritical High temperature H2O Supercritical H2O Packed bed thermocline Supercritical Low temperature CO2 Supercritical CO2 Two tank nitrate salt Supercritical High temperature CO2 Supercritical CO2 Packed bed thermocline Supercritical Several conclusions have been drawn from the results of the study, as follows: 1) The use of supercritical H2O as the heat transport fluid in a packed bed thermocline is likely not a practical approach. The specific heat of the fluid is a strong function of the temperatures at values near 400 °C, and the temperature profile in the bed during a charging cycle is markedly different than the profile during a discharging cycle. 2) The use of supercritical CO2 as the heat transport fluid in a packed bed thermocline is judged to be technically feasible. Nonetheless, the high operating pressures for the supercritical fluid require the use of pressure vessels to contain the storage inventory. The unit cost of the two-tank nitrate salt system is approximately $24/kWht, while the unit cost of the high pressure thermocline system is nominally 10 times as high. 3) For the supercritical fluids, the outer crown temperatures of the receiver tubes are in the range of 700 to 800 °C. At temperatures of 700 °C and above

  14. Reversible temperature regulation of electrical and thermal conductivity using liquid–solid phase transitions

    Science.gov (United States)

    Zheng, Ruiting; Gao, Jinwei; Wang, Jianjian; Chen, Gang

    2011-01-01

    Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions. PMID:21505445

  15. Reversible temperature regulation of electrical and thermal conductivity using liquid-solid phase transitions.

    Science.gov (United States)

    Zheng, Ruiting; Gao, Jinwei; Wang, Jianjian; Chen, Gang

    2011-01-01

    Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions.

  16. An Approach for Designing Thermal Management Systems for Electric and Hybrid Vehicle Battery Packs

    International Nuclear Information System (INIS)

    Pesaran, Ahmad A.; Keyser, Matthew; Burch, Steve

    1999-01-01

    If battery packs for electric vehicles (EVs) and hybrid electric vehicles (HEVs) are to operate effectively in all climates, thermal management of the packs is essential. In this paper, we will review a systematic approach for designing and evaluating battery pack thermal management systems. A thermal management system using air as the heat transfer medium is less complicated than a system using liquid cooling/heating. Generally, for parallel HEVs, an air thermal management system is adequate, whereas for EVs and series HEVs, liquid-based systems may be required for optimum thermal performance. Further information on battery thermal management can be found on the Web site www.ctts.nrel.gov/BTM

  17. The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

    Science.gov (United States)

    Latta, A. F.; Bowyer, J. M.; Fujita, T.

    1979-01-01

    This paper presents the performance and cost of four 10-MWe advanced solar thermal electric power plants sited in various regions of the continental United States. Each region has different insolation characteristics which result in varying collector field areas, plant performance, capital costs, and energy costs. The paraboloidal dish, central receiver, cylindrical parabolic trough, and compound parabolic concentrator (CPC) comprise the advanced concepts studied. This paper contains a discussion of the regional insolation data base, a description of the solar systems' performances and costs, and a presentation of a range for the forecast cost of conventional electricity by region and nationally over the next several decades.

  18. Report on Transparency. Final version CWE. IG Transparency. Electricity Regional Initiative Central Western Regional Electricity Market

    International Nuclear Information System (INIS)

    2007-12-01

    The Central Western Electricity Regional Energy Market (REM), which is a part of ERGEG's Electricity Regional Initiative, is engaged in harmonizing congestion management and transparency in the Central Western electricity market consisting of Belgium, France, Germany, Luxemburg and The Netherlands. his report contains transparency requirements based on the Congestion Management Guidelines (Commission Decision of 9 November 2006, 2006/770/EC, amending the Annex to Regulation (EC) 1228/2003 on conditions for access to transmission network for cross-border exchanges in electricity, hereinafter cited as CM Guidelines) but taking also into account ERGEG Guidelines of Good Practice on Information Management and Transparency (GGP-IMT). Generally, the basis for harmonization of the transparency rules within the Central Western REM is provided by this report. However, there are some restrictions, it has to be stressed that the report only refers to the information requirements set out in the CM Guidelines that are regularly updated. Also, national publication requirements which might go beyond what is prescribed here are not touched. Furthermore, the change of the market design or the legal background might require adoptions of the publication requirements foreseen in this report. One of the main impediments identified by the regulators was the data delivery from generation and consumption units located in the distribution grids. Market participants concerned (also generators and significant consumption units) are obliged to provide the TSOs responsible for publication of all relevant data concerning cross-border trade according to point 5.5 CM Guidelines, with the relevant data. Therefore, TSOs shall be able to get data from generators and significant consumption units connected to the transmission network. Consequently, it is proposed here that each NRA or other competent authority could oblige DSOs to provide data on generation connected to distribution grids to the TSOs

  19. On-line energy and battery thermal management for hybrid electric heavy-duty truck

    NARCIS (Netherlands)

    Pham, H.T.; Kessels, J.T.B.A.; Bosch, van den P.P.J.; Huisman, R.G.M.; Nevels, R.M.P.A.

    2013-01-01

    This paper discusses an integrated approach for energy and thermal management to minimize the fuel consumption of a hybrid electric heavy-duty truck. Conventional Energy Management Systems (EMS) operate separately from the Battery Thermal Management System (BTMS) in Hybrid Electric Vehicles (HEVs).

  20. Analysis of Large- Capacity Water Heaters in Electric Thermal Storage Programs

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, Alan L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Anderson, David M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Winiarski, David W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Carmichael, Robert T. [Cadeo Group, Washington D. C. (United States); Mayhorn, Ebony T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fisher, Andrew R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-03-17

    This report documents a national impact analysis of large tank heat pump water heaters (HPWH) in electric thermal storage (ETS) programs and conveys the findings related to concerns raised by utilities regarding the ability of large-tank heat pump water heaters to provide electric thermal storage services.

  1. Performance results of a solar greenhouse combining electrical and thermal energy production

    NARCIS (Netherlands)

    Sonneveld, P.J.; Swinkels, G.L.A.M.; Campen, J.B.; Tuijl, van B.A.J.; Janssen, H.J.J.; Bot, G.P.A.

    2010-01-01

    Performance results are given of a new type of greenhouse, which combines reflection of near infrared radiation (NIR) with electrical power generation using hybrid photovoltaic cell/thermal collector modules. Besides the generation of electrical and thermal energy, the reflection of the NIR will

  2. Differential and directional effects of perfusion on electrical and thermal conductivities in liver.

    Science.gov (United States)

    Podhajsky, Ronald J; Yi, Ming; Mahajan, Roop L

    2009-01-01

    Two different measurement probes--an electrical probe and a thermal conductivity probe--were designed, fabricated, calibrated, and used in experimental studies on a pig liver model that was designed to control perfusion rates. These probes were fabricated by photolithography and mounted in 1.5-mm diameter catheters. We measured the local impedance and thermal conductivity, respectively, of the artificially perfused liver at different flow rates and, by rotating the probes, in different directions. The results show that both the local electrical conductivity and the thermal conductivity varied location to location, that thermal conductivity increased with decreased distance to large blood vessels, and that significant directional differences exist in both electrical and thermal conductivities. Measurements at different perfusion rates demonstrated that both the local electrical and local thermal conductivities increased linearly with the square root of perfusion rate. These correlations may be of great value to many energy-based biomedical applications.

  3. Characterization of Contact and Bulk Thermal Resistance of Laminations for Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Cousineau, J. Emily [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DeVoto, Doug [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Mihalic, Mark [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-06-30

    The ability to remove heat from an electric machine depends on the passive stack thermal resistances within the machine and the convective cooling performance of the selected cooling technology. This report focuses on the passive thermal design, specifically properties of the stator and rotor lamination stacks. Orthotropic thermal conductivity, specific heat, and density are reported. Four materials commonly used in electric machines were tested, including M19 (29 and 26 gauge), HF10, and Arnon 7 materials.

  4. Analysis and optimization of hybrid electric vehicle thermal management systems

    Science.gov (United States)

    Hamut, H. S.; Dincer, I.; Naterer, G. F.

    2014-02-01

    In this study, the thermal management system of a hybrid electric vehicle is optimized using single and multi-objective evolutionary algorithms in order to maximize the exergy efficiency and minimize the cost and environmental impact of the system. The objective functions are defined and decision variables, along with their respective system constraints, are selected for the analysis. In the multi-objective optimization, a Pareto frontier is obtained and a single desirable optimal solution is selected based on LINMAP decision-making process. The corresponding solutions are compared against the exergetic, exergoeconomic and exergoenvironmental single objective optimization results. The results show that the exergy efficiency, total cost rate and environmental impact rate for the baseline system are determined to be 0.29, ¢28 h-1 and 77.3 mPts h-1 respectively. Moreover, based on the exergoeconomic optimization, 14% higher exergy efficiency and 5% lower cost can be achieved, compared to baseline parameters at an expense of a 14% increase in the environmental impact. Based on the exergoenvironmental optimization, a 13% higher exergy efficiency and 5% lower environmental impact can be achieved at the expense of a 27% increase in the total cost.

  5. French studies on the thermal effluents of electric power plants

    International Nuclear Information System (INIS)

    Dezes-Cadiere, H.

    1976-01-01

    This report presents a synthesis of studies made in France in the thermal effluent field: thermal power plant cooling systems, transfer and dispersion of thermal effluents in the receptive media, effects of thermal effluents on water physicochemistry and biochemistry, effects of thermal effluents on aquatic ecosystems, and, possibilities of waste heat recovery with the view of utilization in agriculture, aquaculture and district heating. A catalogue of French organizations working or having data on thermal effluents is presented, as also an alphabetical list of the contacted persons. A bibliography of French documents concerning the previously mentioned studies is finally given (193 refs.) [fr

  6. 75 FR 76394 - Central Electric Power Cooperative, Inc.: Notice of Intent To Prepare an Environmental Impact...

    Science.gov (United States)

    2010-12-08

    ... Elementary School, 8900 Highway 17 North, McClellanville, SC 29458. RUS, Central Electric, and Mangi... Register and in local newspapers. The USFS may issue a separate ROD for the proposal, which may be subject...

  7. Studies of Electrical and Thermal Conductivities of Sheared Multi-Walled Carbon Nanotube with Isotactic Polypropylene Polymer Composites

    Directory of Open Access Journals (Sweden)

    Parvathalu Kalakonda

    2015-01-01

    at higher temperature due to isotropic electrical and thermal contact in both directions. Oriented MWCNT/iPP nanocomposites exhibit higher electrical and thermal conductivities, attributed primarily by orientation of nanotubes due to the shearing fabrication process.

  8. Thermoelectric System in Different Thermal and Electrical Configurations: Its Impact in the Figure of Merit

    Directory of Open Access Journals (Sweden)

    Alexander Vargas-Almeida

    2013-05-01

    Full Text Available In this work, we analyze different configurations of a thermoelectric system (TES composed of three thermoelectric generators (TEGs. We present the following considerations: (a TES thermally and electrically connected in series (SC; (b TES thermally and electrically connected in parallel (PSC; and (c parallel thermally and series electrical connection (SSC. We assume that the parameters of the TEGs are temperature-independent. The systems are characterized by three parameters, as it has been showed in recent investigations, namely, its internal electrical resistance, R, thermal conductance under open electrical circuit condition, K, and Seebeck coefficient α. We derive the equivalent parameters for each of the configurations considered here and calculate the Figure of Merit Z for the equivalent system. We show the impact of the configuration of the system on Z, and we suggest optimum configuration. In order to justify the effectiveness of the equivalent Figure of Merit, the corresponding efficiency has been calculated for each configuration.

  9. Determining an energy-optimal thermal management strategy for electric driven vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Suchaneck, Andre; Probst, Tobias; Puente Leon, Fernando [Karlsruher Institut fuer Technology (KIT), Karlsruhe (Germany). Inst. of Industrial Information Technology (IIIT)

    2012-11-01

    In electric, hybrid electric and fuel cell vehicles, thermal management may have a significant impact on vehicle range. Therefore, optimal thermal management strategies are required. In this paper a method for determining an energy-optimal control strategy for thermal power generation in electric driven vehicles is presented considering all controlled devices (pumps, valves, fans, and the like) as well as influences like ambient temperature, vehicle speed, motor and battery and cooling cycle temperatures. The method is designed to be generic to increase the thermal management development process speed and to achieve the maximal energy reduction for any electric driven vehicle (e.g., by waste heat utilization). Based on simulations of a prototype electric vehicle with an advanced cooling cycle structure, the potential of the method is shown. (orig.)

  10. electrical-thermal coupling of induction machine for improved

    African Journals Online (AJOL)

    user

    parameter method was used in the thermal model of the machine. The system of ... Thermal modeling is important for design purpose, fault detection ... dependent problems are challenging both in software development ... numerical solution.

  11. Electro-thermal analysis and integration issues of lithium ion battery for electric vehicles

    International Nuclear Information System (INIS)

    Saw, L.H.; Ye, Y.; Tay, A.A.O.

    2014-01-01

    Highlights: • We modeled the electrical and thermal behavior of the Li-ion battery. • We validated the simulation results with experimental studies. • We compared the thermal performance of different size of cylindrical cells. • We investigated the integration issues of cylindrical cells into battery pack. - Abstract: Electrical and thermal characteristics of lithium-ion battery packs in electric vehicles in different operating conditions are important in order to design the battery pack thermal management system. In this work, electrical and thermal behaviors of different size of LiFePO 4 cylindrical cells are investigated under various operating conditions. The simulation results show good agreement with the experimental data under various operating modes. Due to the large thermal resistance of layered active material in a Li-ion cell, the temperature difference in the radial direction is significantly correlated with a diameter of cell and I t -rates. Compared with natural convection, strong forced convection will reduce the temperature uniformity in the cell and accelerate the thermal aging rate. Lastly, integration issues of the cells into a battery pack are discussed from mechanical, electrical, thermal, control and monitoring, manufacturing and maintenance aspects. These issues could impact the performance, cost, driving range and life cycle of the battery pack in electric vehicles

  12. Thermal Effusivity Determination of Metallic Films of Nanometric Thickness by the Electrical Micropulse Method

    Science.gov (United States)

    Lugo, J. M.; Oliva, A. I.

    2017-02-01

    The thermal effusivity of gold, aluminum, and copper thin films of nanometric thickness (20 nm to 200 nm) was investigated in terms of the films' thickness. The metallic thin films were deposited onto glass substrates by thermal evaporation, and the thermal effusivity was estimated by using experimental parameters such as the specific heat, thermal conductivity, and thermal diffusivity values obtained at room conditions. The specific heat, thermal conductivity, and thermal diffusivity values of the metallic thin films are determined with a methodology based on the behavior of the thermal profiles of the films when electrical pulses of few microseconds are applied at room conditions. For all the investigated materials, the thermal effusivity decreases with decreased thickness. The thermal effusivity values estimated by the presented methodology are consistent with other reported values obtained under vacuum conditions and more elaborated methodologies.

  13. Thermal acclimation and thyroxine treatment modify the electric organ discharge frequency in an electric fish, Apteronotus leptorhynchus.

    Science.gov (United States)

    Dunlap, K D; Ragazzi, M A

    2015-11-01

    In ectotherms, the rate of many neural processes is determined externally, by the influence of the thermal environment on body temperature, and internally, by hormones secreted from the thyroid gland. Through thermal acclimation, animals can buffer the influence of the thermal environment by adjusting their physiology to stabilize certain processes in the face of environmental temperature change. The electric organ discharge (EOD) used by weak electric fish for electrocommunication and electrolocation is highly temperature sensitive. In some temperate species that naturally experience large seasonal fluctuations in environmental temperature, the thermal sensitivity (Q10) of the EOD shifts after long-term temperature change. We examined thermal acclimation of EOD frequency in a tropical electric fish, Apteronotus leptorhynchus that naturally experiences much less temperature change. We transferred fish between thermal environments (25.3 and 27.8 °C) and measured EOD frequency and its thermal sensitivity (Q10) over 11 d. After 6d, fish exhibited thermal acclimation to both warming and cooling, adjusting the thermal dependence of EOD frequency to partially compensate for the small change (2.5 °C) in water temperature. In addition, we evaluated the thyroid influence on EOD frequency by treating fish with thyroxine or the anti-thyroid compound propylthiouricil (PTU) to stimulate or inhibit thyroid activity, respectively. Thyroxine treatment significantly increased EOD frequency, but PTU had no effect. Neither thyroxine nor PTU treatment influenced the thermal sensitivity (Q10) of EOD frequency during acute temperature change. Thus, the EOD of Apteronotus shows significant thermal acclimation and responds to elevated thyroxine. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Thermal and Arc Flash Analysis of Electric Motor Drives in Distribution Networks

    OpenAIRE

    Nikolovski, Srete; Mlakić, Dragan; Alibašić, Emir

    2017-01-01

    The paper presents thermal analysis and arc flash analysis taking care of protection relays coordination settings for electric motor drives connected to the electrical network. Power flow analysis is performed to check if there are any voltage and loading violation conditions in the system. Fault analysis is performed to check the short circuit values and compute arc flash energy dissipated at industrial busbars to eliminate damage to electrical equipment and electrical shocks and hazard to p...

  15. PID temperature controller in pig nursery: improvements in performance, thermal comfort, and electricity use.

    Science.gov (United States)

    de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Sartor, Karina

    2016-08-01

    The use of smarter temperature control technologies in heating systems can optimize the use of electric power and performance of piglets. Two control technologies of a resistive heating system were assessed in a pig nursery: a PID (proportional, integral, and derivative) controller and a thermostat. The systems were evaluated regarding thermal environment, piglet performance, and use of electric power for 99 days. The heating system with PID controller improved the thermal environment conditions and was significantly (P PID-controlled heating system is more efficient in electricity use and provides better conditions for thermal comfort and animal performance than heating with thermostat.

  16. Comparative status and development trends of central electricity supply technologies in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Kolb, G.

    1989-01-01

    This paper describes the present situation in the public electricity sector of the FRG with its legal and political constraints, to identify the development trends of the supply technologies for central electricity in regard to their application potential during the forthcoming 10 to 20 years. Summarizing expectations and conclusions are drawn on the foreseeable contribution of the electricity supply sector to the aspired CO 2 -reductions in the FRG

  17. Electrical and Thermal Conductivity and Conduction Mechanism of Ge2Sb2Te5 Alloy

    Science.gov (United States)

    Lan, Rui; Endo, Rie; Kuwahara, Masashi; Kobayashi, Yoshinao; Susa, Masahiro

    2017-11-01

    Ge2Sb2Te5 alloy has drawn much attention due to its application in phase-change random-access memory and potential as a thermoelectric material. Electrical and thermal conductivity are important material properties in both applications. The aim of this work is to investigate the temperature dependence of the electrical and thermal conductivity of Ge2Sb2Te5 alloy and discuss the thermal conduction mechanism. The electrical resistivity and thermal conductivity of Ge2Sb2Te5 alloy were measured from room temperature to 823 K by four-terminal and hot-strip method, respectively. With increasing temperature, the electrical resistivity increased while the thermal conductivity first decreased up to about 600 K then increased. The electronic component of the thermal conductivity was calculated from the Wiedemann-Franz law using the resistivity results. At room temperature, Ge2Sb2Te5 alloy has large electronic thermal conductivity and low lattice thermal conductivity. Bipolar diffusion contributes more to the thermal conductivity with increasing temperature. The special crystallographic structure of Ge2Sb2Te5 alloy accounts for the thermal conduction mechanism.

  18. Electrical and Thermal Conductivity and Conduction Mechanism of Ge2Sb2Te5 Alloy

    Science.gov (United States)

    Lan, Rui; Endo, Rie; Kuwahara, Masashi; Kobayashi, Yoshinao; Susa, Masahiro

    2018-06-01

    Ge2Sb2Te5 alloy has drawn much attention due to its application in phase-change random-access memory and potential as a thermoelectric material. Electrical and thermal conductivity are important material properties in both applications. The aim of this work is to investigate the temperature dependence of the electrical and thermal conductivity of Ge2Sb2Te5 alloy and discuss the thermal conduction mechanism. The electrical resistivity and thermal conductivity of Ge2Sb2Te5 alloy were measured from room temperature to 823 K by four-terminal and hot-strip method, respectively. With increasing temperature, the electrical resistivity increased while the thermal conductivity first decreased up to about 600 K then increased. The electronic component of the thermal conductivity was calculated from the Wiedemann-Franz law using the resistivity results. At room temperature, Ge2Sb2Te5 alloy has large electronic thermal conductivity and low lattice thermal conductivity. Bipolar diffusion contributes more to the thermal conductivity with increasing temperature. The special crystallographic structure of Ge2Sb2Te5 alloy accounts for the thermal conduction mechanism.

  19. Thermal Environment for Classrooms. Central System Approach to Air Conditioning.

    Science.gov (United States)

    Triechler, Walter W.

    This speech compares the air conditioning requirements of high-rise office buildings with those of large centralized school complexes. A description of one particular air conditioning system provides information about the system's arrangement, functions, performance efficiency, and cost effectiveness. (MLF)

  20. Electric machinery and drives in thermal power stations

    International Nuclear Information System (INIS)

    1974-01-01

    The following subjects were dealt with during the VDE meeting: 1) Requirements made by the electric network on the generators and their excitation equipment, and the influence thereof on their design; 2) requirements made by the power station process on the electric drives and the influence thereof on type and design; 3) requirements made on protective measures from the point of the electric power station machinery. (TK) [de

  1. Assessing energy efficiency of electric car bottom furnaces intended for thermal energization of minerals

    Science.gov (United States)

    Nizhegorodov, A. I.

    2017-01-01

    The paper deals with a new concept of electric furnaces for roasting and thermal energization of vermiculite and other minerals with vibrational transportation of a single-layer mass under constant thermal field. The paper presents performance calculation and comparative assessment of energy data for furnaces of different modifications: flame and electric furnaces with three units, furnaces with six units and ones with series-parallel connection of units, and furnaces of new concept.

  2. Thermal electric effects and heat generation in polypyrrole coated PET fabrics

    OpenAIRE

    Avloni, J.; Florio, L.; Henn, A. R.; Sparavigna, A.

    2007-01-01

    Polypyrrole chemically synthesized on PET gives rise to textiles with a high electric conductivity, suitable for several applications from antistatics to electromagnetic interference shielding devices. Here, we discuss investigations on thermal electric performances of the polypyrrole coated PET in a wide range of temperatures above room temperature. The Seebeck coefficient turns out to be comparable with that of metal thermocouple materials. Since polypyrrole shows extremely low thermal diff...

  3. High efficiency thermal to electric energy conversion using selective emitters and spectrally tuned solar cells

    Science.gov (United States)

    Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

    1992-01-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1500 K. Depending on the nature of parasitic losses, overall thermal-to-electric conversion efficiencies greater than 20 percent are feasible.

  4. Vascular Abnormalities Associated with Thermal and Electrical Trauma,

    Science.gov (United States)

    1992-01-01

    Knippenberg, R,W.: Temporal relationships among immunologic alterations in a guinea pig model of thermal injury. J. Infect, Dis., 153:1098, 1986. 7...decompression venous access to 72 hr in thermally injured patients of the stomach and alimentation provided either by is supported by the documented

  5. Experiment Investigation on Electrical and Thermal Performances of a Semitransparent Photovoltaic/Thermal System with Water Cooling

    Directory of Open Access Journals (Sweden)

    Guiqiang Li

    2014-01-01

    Full Text Available Different from the semitransparent building integrated photovoltaic/thermal (BIPV/T system with air cooling, the semitransparent BIPV/T system with water cooling is rare, especially based on the silicon solar cells. In this paper, a semitransparent photovoltaic/thermal system (SPV/T with water cooling was set up, which not only would provide the electrical power and hot water, but also could attain the natural illumination for the building. The PV efficiency, thermal efficiency, and exergy analysis were all adopted to illustrate the performance of SPV/T system. The results showed that the PV efficiency and the thermal efficiency were about 11.5% and 39.5%, respectively, on the typical sunny day. Furthermore, the PV and thermal efficiencies fit curves were made to demonstrate the SPV/T performance more comprehensively. The performance analysis indicated that the SPV/T system has a good application prospect for building.

  6. CENTRAL NUCLEAR ELECTRIC, A FUTURE OF ROMANIAN ENERGY

    Directory of Open Access Journals (Sweden)

    Gabriel I. NĂSTASE

    2010-05-01

    Full Text Available Official statistics show the year increasing the share of electricity produced in nuclear power plants. The most developed nuclear energy programs are: the United States, France, Japan, Germany and Canada. Although Romania was among the first countries in Eastern Europe that had a nuclear research program, switching to nuclear power reactors has been extremely difficult and slow. The implications of this decisionmaking process were the first political and then economic. There were a series of oscillations between Wer system offered by the USSR and the CANDU-PHWR supplied by Canada. Considering nuclear reactors Wer insufficiently protected against a nuclear accident, and the total requested by the former Soviet Union on the nuclear fuel cycle, the decision of us have opted for CANDU reactor, fueled with natural uranium, moderated and cooled with heavy water.

  7. An investigation of thermal anomalies in the Central American volcanic chain and evaluation of the utility of thermal anomaly monitoring in the prediction of volcanic eruptions. [Central America

    Science.gov (United States)

    Stoiber, R. E. (Principal Investigator); Rose, W. I., Jr.

    1975-01-01

    The author has identified the following significant results. Ground truth data collection proves that significant anomalies exist at 13 volcanoes within the test site of Central America. The dimensions and temperature contrast of these ten anomalies are large enough to be detected by the Skylab 192 instrument. The dimensions and intensity of thermal anomalies have changed at most of these volcanoes during the Skylab mission.

  8. Possibilities for retrofitting of the existing thermal electric power plants using solar power technologies

    International Nuclear Information System (INIS)

    Matjanov, Erkinjon K.; Abduganieva, Farogat A.; Aminov, Zarif Z.

    2012-01-01

    Full text: Total installed electric power output of the existing thermal electric power plants in Uzbekistan is reaches 12 GW. Thermal electric power plants, working on organic fuel, produce around 88 % of the electricity in the country. The emission coefficient of CO 2 gases is 620 gram/kwph. Average electric efficiency of the thermal electric power plants is 32.1 %. The mentioned above data certifies, that the existing thermal electric power plants of Uzbekistan are physically and morally aged and they need to be retrofitted. Retrofitting of the existing thermal electric power plants can be done by several ways such as via including gas turbine toppings, by using solar technologies, etc. Solar thermal power is a relatively new technology which has already shown its enormous promise. With few environmental impacts and a massive resource, it offers a comparable opportunity to the sunniest Uzbekistan. Solar thermal power uses direct sunlight, so it must be sited in regions with high direct solar radiation. In many regions, one square km of land is enough to generate as much as 100-120 GWh of electricity per year using the solar thermal technology. This is equivalent to the annual production of a 50 MW conventional coal or gas-fired mid-load power plant. Solar thermal power plants can be designed for solar-only or for hybrid operation. Producing electricity from the energy in the sun's rays is a straightforward process: direct solar radiation can be concentrated and collected by a range of Concentrating Solar Power technologies to provide medium- to high temperature heat. This heat is then used to operate a conventional power cycle, for example through a steam turbine or a Stirling engine. Solar heat collected during the day can also be stored in liquid or solid media such as molten salts, ceramics, concrete or, in the future, phase-changing salt mixtures. At night, it can be extracted from the storage medium thereby continuing turbine operation. Currently, the

  9. Thermal, electrical and mechanical properties during cristallization of the amorphous alloy Co33Zr67

    International Nuclear Information System (INIS)

    Nicolaus, M.M.

    1992-01-01

    Topic of this work is to study the crystallization process of amorphous CO 33 Zr 67 alloy and to characterize its thermal, electrical and mechanical properties. Studies were carried out by calorimetry, vibrating-Reed technique, electrical-resistance measurement, dilatometry, X-ray diffraction and electron-transmission-microscopy. Results of microstructure analysis, kinetic analysis, specific heat, dilatometry (isothermal and non-isothermal) and electrical resistance are discussed in detail here

  10. Interpretation of Simultaneous Mechanical-Electrical-Thermal Failure in a Lithium-Ion Battery Module: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao; Santhanagopalan, Shriram; Stock, Mark J.; Brunhart-Lupo, Nicholas; Gruchalla, Kenny

    2016-12-01

    Lithium-ion batteries are currently the state-of- the-art power sources for electric vehicles, and their safety behavior when subjected to abuse, such as a mechanical impact, is of critical concern. A coupled mechanical-electrical-thermal model for simulating the behavior of a lithium-ion battery under a mechanical crush has been developed. We present a series of production-quality visualizations to illustrate the complex mechanical and electrical interactions in this model.

  11. (HBCU) Thermal-Electric Propulsion With Magnetoplasmadynamic Acceleration

    National Research Council Canada - National Science Library

    Tabibi, Bagher

    1998-01-01

    .... An insitu technique, Pitot tube method, was used to measure the total and static pressures of the core flow of the thermal plume in steady state operation in order to characterize and benchmark...

  12. Hyperbaric oxygen therapy attenuates central sensitization induced by a thermal injury in humans

    DEFF Research Database (Denmark)

    Rasmussen, V M; Borgen, A E; Jansen, E C

    2015-01-01

    BACKGROUND: Hyperbaric oxygen (HBO2 ) treatment has in animal experiments demonstrated antinociceptive effects. It was hypothesized that these effects would attenuate secondary hyperalgesia areas (SHAs), an expression of central sensitization, after a first-degree thermal injury in humans. METHODS...... was demonstrated. However, in the nine volunteers starting with the control session, a statistical significant attenuation of SHAs was demonstrated in the HBO2 session (P = 0.004). CONCLUSIONS: The results indicate that HBO2 therapy in humans attenuates central sensitization induced by a thermal skin injury......, compared with control. These new and original findings in humans corroborate animal experimental data. The thermal injury model may give impetus to future human neurophysiological studies exploring the central effects of hyperbaric oxygen treatment....

  13. Suburban Housing Development and Off-Grid Electric Power Supply Assessment for North-Central Nigeria

    Directory of Open Access Journals (Sweden)

    Ibikunle Olalekan Ogundari

    2017-01-01

    Full Text Available Energy infrastructures in North-Central Nigeria are inadequate and grid electricity is unable to meet suburban housing electricity demand. The alternative power-supply options proposed by government for the region require appropriation analysis for selection. Four public housing estates in suburban Abuja are selected for electricity demand analysis under conventional and energy-efficient lighting scenarios; then techno-economic parameters of two off-grid electric power supply systems (PV and Diesel-powered generation to meet these electricity demands are evaluated. An energy techno-economic assessment methodology is used. The study determines the energy-efficient lighting system is appropriate with 40% energy savings relative to the Conventional Lighting Systems. The diesel generator alternative power-supply option has Life Cycle Costs almost 4 times those of the PV option. The study established the PV-energy-efficient lighting system as the most feasible off-grid electric power supply alternative for implementation.

  14. Electrically conductive, black thermal control coatings for spacecraft applications. III - Plasma-deposited ceramic matrix

    Science.gov (United States)

    Hribar, V. F.; Bauer, J. L.; O'Donnell, T. P.

    1987-01-01

    Five black, electrically-conductive thermal control coatings have been formulated and tested for application on the Galileo spacecraft. The coatings consist of both organic and inorganic systems applied on titanium, aluminum, and glass/epoxy composite surfaces. The coatings were tested under simulated space environment conditions. Coated specimens were subjected to thermal radiation, convective and combustive heating, and cryogenic conditions over a temperature range between -196 C and 538 C. Mechanical, physical, thermal, electrical, and thermooptical properties are presented for one of these coatings. This paper describes the preparation, characteristics, and spraying of iron titanate on titanium and aluminum, and presents performance results.

  15. Research management at the Central Electricity Generating Board

    International Nuclear Information System (INIS)

    Broom, T.

    1986-01-01

    CEGB is responsible for power generation and transmission in England and Wales, and has a yearly production of some 230 TWh. There are three main fields of research: conventional generation and transmission, nuclear generation and environmental consequences of electricity generation. All laboratories carry out research in each field, though there are definite concentrations of specialities. The organisation of the research management changed emphasis in 1981 from an 'areal' (managing of individual institutes) to a topical approach (responsibilities for research fields). Good research requires good personnel, but also care on the part of the manager for the personal interests of the staff. There must be good cooperation between the researchers themselves, between researchers and managers, and between CEGB staff and researchers elsewhere. It is considered of prime importance that the researchers be true experts in their fields and that they maintain their scientific integrity. Other information is obtained by exchanging reports with comparable organisations, e.g. the KEMA in The Netherlands. Such an exchange requires mutual trust and research managers must therefore behave as true ambassadors. (Auth.)

  16. Big-Data-Based Thermal Runaway Prognosis of Battery Systems for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Jichao Hong

    2017-07-01

    Full Text Available A thermal runaway prognosis scheme for battery systems in electric vehicles is proposed based on the big data platform and entropy method. It realizes the diagnosis and prognosis of thermal runaway simultaneously, which is caused by the temperature fault through monitoring battery temperature during vehicular operations. A vast quantity of real-time voltage monitoring data is derived from the National Service and Management Center for Electric Vehicles (NSMC-EV in Beijing. Furthermore, a thermal security management strategy for thermal runaway is presented under the Z-score approach. The abnormity coefficient is introduced to present real-time precautions of temperature abnormity. The results illustrated that the proposed method can accurately forecast both the time and location of the temperature fault within battery packs. The presented method is flexible in all disorder systems and possesses widespread application potential in not only electric vehicles, but also other areas with complex abnormal fluctuating environments.

  17. Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jin Jiezhu; Wang Qing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Haque, M A [Department of Mechanical and Nuclear Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

    2010-05-26

    We performed simultaneous characterization of electrical and thermal conductivity of 55 nm thick polyaniline (PANI) thin films doped with different levels of camphor sulfonic acids (CSAs). The effect of the doping level is more pronounced on electrical conductivity than on thermal conductivity of PANIs, thereby greatly affecting their ratio that determines the thermoelectric efficiency. At the 60% (the molar ratio of CSA to phenyl-N repeat unit of PANI) doping level, PANI exhibited the maximum electrical and thermal conductivity due to the formation of mostly delocalized structures. Whereas polarons are the charge carriers responsible for the electrical conduction, phonons are believed to play a dominant role in the heat conduction in nanoscale doped PANI thin films.

  18. Investigation of the Promotion of Wind Power Consumption Using the Thermal-Electric Decoupling Techniques

    Directory of Open Access Journals (Sweden)

    Shuang Rong

    2015-08-01

    Full Text Available In the provinces of north China, combined heat and electric power generations (CHP are widely utilized to provide both heating source and electricity. While, due to the constraint of thermal-electric coupling within CHP, a mass of wind turbines have to offline operate during heating season to maintain the power grid stability. This paper proposes a thermal-electric decoupling (TED approach to release the energy waste. Within the thermal-electric decoupling system, heat storage and electric boiler/heat pump are introduced to provide an auxiliary thermal source during hard peak shaving period, thus relying on the participation of an outside heat source, the artificial electric power output change interval could be widened to adopt more wind power and reduce wind power curtailment. Both mathematic models and methods are proposed to calculate the evaluation indexes to weight the effect of TED, by using the Monte Carlo simulation technique. Numerical simulations have been conducted to demonstrate the effectiveness of the proposed methods, and the results show that the proposed approach could relieve up to approximately 90% of wind power curtailment and the ability of power system to accommodate wind power could be promoted about 32%; moreover, the heating source is extended, about 300 GJ heat could be supplied by TED during the whole heating season, which accounts for about 18% of the total heat need.

  19. Optimization of thermal efficiency of nuclear central power like as PWR

    International Nuclear Information System (INIS)

    Lapa, Nelbia da Silva

    2005-10-01

    The main purpose of this work is the definition of operational conditions for the steam and power conservation of Pressurized Water Reactor (PWR) plant in order to increase its system thermal efficiency without changing any component, based on the optimization of operational parameters of the plant. The thermal efficiency is calculated by a thermal balance program, based on conservation equations for homogeneous modeling. The circuit coefficients are estimated by an optimization tool, allowing a more realistic thermal balance for the plans under analysis, as well as others parameters necessary to some component models. With the operational parameter optimization, it is possible to get a level of thermal efficiency that increase capital gain, due to a better relationship between the electricity production and the amount of fuel used, without any need to change components plant. (author)

  20. How to design electrical systems with central control capability for industrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Cigolini, S.; Galati, G.; Lionetto, P.F.; Stiz, M. (Siemens, Milan (Italy) Centro Elettrotecnico Sperimentale Italiano, Milan (Italy))

    1991-12-01

    The modern centralized control system, incorporating microprocessors, constitutes an extremely efficacious instrument for the management of an industrial plant's electrical system and provides the performance, reliability, flexibility and safety features required by today's technologically advanced plant processes. The use of intelligent centralized control systems, capable of autonomous operation and dialoguing with industrial plant electrical systems, simplifies the design of the overall plant. This paper reviews the main design criteria for the automated systems and gives examples of some suitable commercially available intelligent systems.

  1. Electric Motor Thermal Management Research: Annual Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-10-19

    Past work in the area of active convective cooling provided data on the average convective heat transfer coefficients of circular orifice automatic transmission fluid (ATF) jets impinging on stationary targets intended to represent the wire bundle surface of the motor end-winding. Work during FY16 focused on the impact of alternative jet geometries that could lead to improved cooling over a larger surface of the motor winding. Results show that the planar jet heat transfer coefficients over a small (12.7-mm-diameter) target surface are not too much lower than for the circular orifice jet in which all of the ATF from the jet impinges on the target surface. The planar jet has the potential to achieve higher heat transfer over a larger area of the motor end winding. A new test apparatus was constructed to measure the spatial dependence of the heat transfer relative to the jet nozzle over a larger area representative of a motor end-winding. The tested planar flow geometry has the potential to provide more uniform cooling over the full end-winding surface versus the conventional jet configuration. The data will be used by motor designers to develop thermal management strategies to improve motor power density. Work on passive thermal design in collaboration with Oak Ridge National Laboratory to measure the thermal conductivity of wire bundle samples representative of end-winding and slot-winding materials was completed. Multiple measurement techniques were compared to determine which was most suitable for measuring composite wire bundle samples. NREL used a steady-state thermal resistance technique to measure the direction-dependent thermal conductivity. The work supported new interactions with industry to test new materials and reduce passive-stack thermal resistance in motors, leading to motors with increased power density. NREL collaborated with Ames Laboratory in the area of material characterization. The work focused on measuring the transverse rupture strength of

  2. Central receiver solar thermal power system, phase 1. Progress report for period ending December 31, 1975

    Energy Technology Data Exchange (ETDEWEB)

    None

    1976-04-01

    The program objective is the preliminary design of a 10 MWe pilot solar power plant supported by major subsystem experiments. Progress is reported on the following task elements: 10 MWe pilot plant; collector subsystem design and analysis; receiver subsystem requirements; receiver subsystem design; thermal storage subsystem; electrical power generation subsystem; and pilot plant architectural engineering and support. (WDM)

  3. Economic impact of solar thermal electricity deployment in Spain

    International Nuclear Information System (INIS)

    Caldes, N.; Varela, M.; Santamaria, M.; Saez, R.

    2009-01-01

    The objective of the work is to estimate the socio-economic impacts of increasing the installed solar thermal energy power capacity in Spain. Using an input-output (I-O) analysis, this paper estimates the increase in the demand for goods and services as well as in employment derived from solar thermal plants in Spain under two different scenarios: (a) based on two solar thermal power plants currently in operation (with 50 and 17 MW of installed capacity); (b) the compliance to the Spanish Renewable Energy Plan (PER) 2005-2010 reaching 500 MW by 2010. Results show that the multiplier effect of the PER is 2.3 and the total employment generated would reach 108,992 equivalent full-time jobs of 1 year of duration. Despite this is an aggregated result, this figure represents 4.5% of current Spanish unemployment. It can be concluded that the socio-economic effect of the PER's solar thermal installed capacity goal would be remarkable.

  4. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief

    International Nuclear Information System (INIS)

    Pérez, Juan J.; Pérez-Cajaraville, Juan J.; Muñoz, Víctor; Berjano, Enrique

    2014-01-01

    Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m −1 ) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of thermal

  5. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief

    Energy Technology Data Exchange (ETDEWEB)

    Pérez, Juan J. [Instituto de Investigación Interuniversitario en Bioingeniería y Tecnología Orientada al Ser Humano, Universitat Politècnica de València, Valencia 46022 (Spain); Pérez-Cajaraville, Juan J. [Pain Unit and Department of Anesthesia and Critical Care, Clínica Universidad de Navarra, University of Navarra, Pamplona 31008 (Spain); Muñoz, Víctor [Neurotherm Spain, Barcelona 08303 (Spain); Berjano, Enrique, E-mail: eberjano@eln.upv.es [Biomedical Synergy, Electronic Engineering Department, Universitat Politècnica de València 46022 (Spain)

    2014-07-15

    Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m{sup −1}) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of

  6. Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief.

    Science.gov (United States)

    Pérez, Juan J; Pérez-Cajaraville, Juan J; Muñoz, Víctor; Berjano, Enrique

    2014-07-01

    Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a "strip lesion" to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m(-1)) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of thermal damage zone dimension.

  7. Possible thermal structure of the eastern part of the central Alps

    International Nuclear Information System (INIS)

    Pasquale, U.

    1987-01-01

    The trend of temperature in respect of depth in lithosphere under the eastern part of the Central Alps between Innsbruck and Graz, using a geothermal model based on the reduced heat production along the vertical and on the thermal conductivity dependence upon temperature and pressure is studied. A linear relationship has been found between the reduced heat flow and the mean surface heat flow

  8. Ice thermal storage air conditioning system for electric load leveling; Denryoku heijunka to hyochikunetsu system

    Energy Technology Data Exchange (ETDEWEB)

    Shigenaga, Y. [Daikin Industries Ltd., Osaka (Japan)

    1998-08-15

    Thermal storage air conditioning system is the one to use energy stored into thermal storing materials by using night electric power and to operate effective air conditioning. Therefore, as load can be treated by the stored energy, volume of the apparatus can be reduced. And, by reduction of the consumed power at day time, it can contribute to leveling of electric power demand. In general, there are two types in the thermal storage method: one is a method to store as thermal energy, and the other is that to store as chemical energy. For conditions required for the storing materials, important elements on their actual uses are not only physical properties such as large thermal storage per unit and easy thermal in- and out-puts, but also safety, long-term reliability, and easy receiving and economics containing future. The ice thermal storage air conditioning system is classified at the viewpoint of type of ice, kind of thermal storing medium, melting method on using cooling and heating, kinds of thermal medium on cooling and heating. 3 refs., 5 figs., 2 tabs.

  9. From centralized hydro-thermal to decentralized renewable : the Austrian challenge

    International Nuclear Information System (INIS)

    Brauner, G.

    2007-01-01

    Austria's electricity production scheme is currently based on 67 per cent hydro power, 25 per cent fossil thermal power and 8 per cent new renewable energy, including wind, biomass, and photovoltaic conversion. As demand on centralized energy systems increases, the power generation, transmission and distribution system in the country will have to be restructured to increase the portion of regenerative generation. Decentralized micro-grid structures are a promising concept for meeting the target of efficiency improvement and renewable generation because they make it possible to use regenerative energy where it is collected. The most efficient way to meet the challenges of efficiency improvement and emission reduction is the replacement of old coal-fired power stations by new combined-cycle gas power stations with combined heat and power. This will reduce both carbon dioxide emissions as well as specific fossil energy demand. However, in just 1 decade the emission reduction achieved by fuel switching and higher efficiency of power stations will be equalized by higher demand, which is growing at an annual rate of 2 per cent. Future energy problems will be characterized by the security of supply; climatic change and the need for clean energy technologies; the lack of transmission-routes; and growing energy demand. The regenerative energy in Austria currently consists of hydraulic large run-of-river hydraulic generation as well as small scale hydro and large scale hydro storage systems. Biomass currently has a total generating capacity of 280 MW and forms 3.14 per cent of generation in Austria. Wind has reached a capacity of 950 MW and forms 3.8 per cent of generation in Austria. It was concluded that the future philosophy in energy supply will not be to try to increase regenerative generation according to growing demand, but to improve end-use efficiency and reduce demand according to the renewable regional potential. 4 refs., 4 figs

  10. Fluid power network for centralized electricity generation in offshore wind farms

    NARCIS (Netherlands)

    Jarquin-Laguna, A.

    2014-01-01

    An innovative and completely different wind-energy conversion system is studied where a centralized electricity generation within a wind farm is proposed by means of a hydraulic network. This paper presents the dynamic interaction of two turbines when they are coupled to the same hydraulic network.

  11. On the evolution, over four generations of paraboloidal dish solar thermal electric power systems

    International Nuclear Information System (INIS)

    Kaneff, S.

    1993-01-01

    After a decade of supplying useful power, the White Cliffs Paraboloidal Dish Solar Thermal Power Station (1100 km west of Sydney) is still operational and has provided major lessons and experience for subsequent developments; particularly for the Molokai/Alburquerque unit built jointly with Power Kinetics Inc (of Troy, USA) for the US Department of Energy. This has, in turn, given valuable guidance for the third generation system now nearing completion in Canberra and employing new collector concepts refined for commercial production and viability. Unlike much dish-oriented R and D, we consider systems of dish arrays supplying central plant as a more attractive proposition than assemblies of dish/engine units, for all but very small systems (<2 MWe). Development has recently commerce on the fourth generation technology which result in a 2 MWe dish system within 2 years, expected to be followed closely by a system of 10 to 20 MWe, preparatory to still larger systems, as the technology evolves and experience is gained. The rationale in this progression in based on the achievement of commercial cost-effectiveness in competition with other energy sources. The direction of evolution is becoming clear and application of the technology to broader spheres than electricity generation is likely. Because of the nature of production methods employed and the ease of installation, system implementation can be rapid. (Author) 29 refs

  12. Improvement and evaluation of thermal, electrical, sealing and mechanical contacts, and their interface materials

    Science.gov (United States)

    Luo, Xiangcheng

    Material contacts, including thermal, electrical, seating (fluid sealing and electromagnetic sealing) and mechanical (pressure) contacts, together with their interface materials, were, evaluated, and in some cases, improved beyond the state of the art. The evaluation involved the use of thermal, electrical and mechanical methods. For thermal contacts, this work evaluated and improved the heat transfer efficiency between two contacting components by developing various thermal interface pastes. Sodium silicate based thermal pastes (with boron nitride particles as the thermally conductive filler) as well as polyethylene glycol (PEG) based thermal pastes were developed and evaluated. The optimum volume fractions of BN in sodium silicate based pastes and PEG based pastes were 16% and 18% respectively. The contribution of Li+ ions to the thermal contact conductance in the PEG-based paste was confirmed. For electrical contacts, the relationship between the mechanical reliability and electrical reliability of solder/copper and silver-epoxy/copper joints was addressed. Mechanical pull-out testing was conducted on solder/copper and silver-epoxy/copper joints, while the contact electrical resistivity was measured. Cleansing of the copper surface was more effective for the reliability of silver-epoxy/copper joint than that of solder/copper joint. For sealing contacts, this work evaluated flexible graphite as an electromagnetic shielding gasket material. Flexible graphite was found to be at least comparable to conductive filled silicone (the state of the art) in terms of the shielding effectiveness. The conformability of flexible graphite with its mating metal surface under repeated compression was characterized by monitoring the contact electrical resistance, as the conformability is important to both electromagnetic scaling and fluid waling using flexible graphite. For mechanical contacts, this work focused on the correlation of the interface structure (such as elastic

  13. Wetting and motion behaviors of water droplet on graphene under thermal-electric coupling field

    Science.gov (United States)

    Zhang, Zhong-Qiang; Dong, Xin; Ye, Hong-Fei; Cheng, Guang-Gui; Ding, Jian-Ning; Ling, Zhi-Yong

    2015-02-01

    Wetting dynamics and motion behaviors of a water droplet on graphene are characterized under the electric-thermal coupling field using classical molecular dynamics simulation method. The water droplet on graphene can be driven by the temperature gradient, while the moving direction is dependent on the electric field intensity. Concretely, the water droplet on graphene moves from the low temperature region to the high temperature region for the relatively weak electric field intensity. The motion acceleration increases with the electric field intensity on graphene, whereas the moving direction switches when the electric field intensity increases up to a threshold. The essence is the change from hydrophilic to hydrophobic for the water droplet on graphene at a threshold of the electric field intensity. Moreover, the driven force of the water droplet caused by the overall oscillation of graphene has important influence on the motion behaviors. The results are helpful to control the wettability of graphene and further develop the graphene-based fluidic nanodevices.

  14. Dispersed solar thermal generation employing parabolic dish-electric transport with field modulated generator systems

    Science.gov (United States)

    Ramakumar, R.; Bahrami, K.

    1981-01-01

    This paper discusses the application of field modulated generator systems (FMGS) to dispersed solar-thermal-electric generation from a parabolic dish field with electric transport. Each solar generation unit is rated at 15 kWe and the power generated by an array of such units is electrically collected for insertion into an existing utility grid. Such an approach appears to be most suitable when the heat engine rotational speeds are high (greater than 6000 r/min) and, in particular, if they are operated in the variable speed mode and if utility-grade a.c. is required for direct insertion into the grid without an intermediate electric energy storage and reconversion system. Predictions of overall efficiencies based on conservative efficiency figures for the FMGS are in the range of 25 per cent and should be encouraging to those involved in the development of cost-effective dispersed solar thermal power systems.

  15. Recouping the thermal-to-electric conversion loss by the use of waste heat

    International Nuclear Information System (INIS)

    Bradley, W.J.

    1976-01-01

    This paper looks at ways to recoup the thermal-to-electric conversion loss of our thermal power generating stations. These stations now produce twice as much low-grade waste heat as they do electricity. We can improve the situation in two ways: by improving the station efficiency, and by utilizing the low-grade heat beneficially. The following options are examined: N 2 O 4 turbines condensing at 10 deg C; power from moderator waste heat; 50 MW heat pump for district heating; industrial parks with integrated waste heat upgrading station. (author)

  16. Experimental investigation on thermal management of electric vehicle battery with heat pipe

    International Nuclear Information System (INIS)

    Rao Zhonghao; Wang Shuangfeng; Wu Maochun; Lin Zirong; Li Fuhuo

    2013-01-01

    Highlights: ► The thermal management system of electric vehicle battery with heat pipes was designed. ► Temperature rise is a key factor for the design of power battery thermal management system. ► Temperature distribution is inevitable to reference for better design of heat pipes used for heat dissipation. ► Heat pipes are effective for power batteries thermal management within electric vehicles. - Abstract: In order to increase the cycle time of power batteries and decrease the overall cost of electric vehicles, the thermal management system equipped with heat pipes was designed according to the heat generated character of power batteries. The experimental result showed that the maximum temperature could be controlled below 50 °C when the heat generation rate was lower than 50 W. Coupled with the desired temperature difference, the heat generation rate should not exceed 30 W. The maximum temperature and temperature difference are kept within desired rang under unsteady operating conditions and cycle testing conditions. Applying heat pipes based power batteries thermal management is an effective method for energy saving in electric vehicles.

  17. Estimation of Equivalent Thermal Conductivity for Impregnated Electrical Windings Formed from Profiled Rectangular Conductors

    OpenAIRE

    Ayat, Sabrina S; Wrobel, Rafal; Goss, James; Drury, David

    2016-01-01

    In order to improve accuracy and reduce model setting-up, and solving time in thermal analysis of electrical machines, transformers and wound passive components, the multi-material winding region is frequently homogenised. The existing winding homogenization techniques are predo-minantly focused on winding constructions with round conductors, where thermal conductivity across conductors is usually assumed to be isotropic. However, for the profiled rectangular conductors that assumption is no ...

  18. Thermal and Electrical Properties of Polyaniline-glycine Composites

    Science.gov (United States)

    Mathavan, T.; Umapathy, S.; Jothirajan, M. A.; Vivekanandam, T. S.; Okram, G. S.

    2011-07-01

    Polymer-amino acid composites were prepared by combining the synthesized polyaniline and glycine in solid state. The samples were characterized by modulated DSC and AFM. Modulated DSC thermogram showed the structural changes occurred while composite formation. D.C electrical conductivity measurements were carried out on the samples in the temperature range of 310 K-85 K by using two-probe method. Analysis of D.C conductivity results revealed that the conductivity was governed by Mott's 2-dimensional variable range hopping.

  19. High-frequency thermal-electrical cycles for pyroelectric energy conversion

    International Nuclear Information System (INIS)

    Bhatia, Bikram; Damodaran, Anoop R.; Cho, Hanna; Martin, Lane W.; King, William P.

    2014-01-01

    We report thermal to electrical energy conversion from a 150 nm thick BaTiO 3 film using pyroelectric cycles at 1 kHz. A microfabricated platform enables temperature and electric field control with temporal resolution near 1 μs. The rapid electric field changes as high as 11 × 10 5  kV/cm-s, and temperature change rates as high as 6 × 10 5  K/s allow exploration of pyroelectric cycles in a previously unexplored operating regime. We investigated the effect of phase difference between electric field and temperature cycles, and electric field and temperature change rates on the electrical energy generated from thermal-electrical cycles based on the pyroelectric Ericsson cycle. Complete thermodynamic cycles are possible up to the highest cycle rates tested here, and the energy density varies significantly with phase shifts between temperature and electric field waveforms. This work could facilitate the design and operation of pyroelectric cycles at high cycle rates, and aid in the design of new pyroelectric systems

  20. Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

    OpenAIRE

    Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

    2016-01-01

    An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is d...

  1. Study into solar thermal electricity export opportunities for the UK

    International Nuclear Information System (INIS)

    1996-01-01

    The overall objectives of the project described in this report were: to provide an assessment of the world-wide opportunities currently available for the development of high temperature solar thermal (H-TSTh) technology; to identify United Kingdom companies and expertise which could benefit from the exploitation of export markets for H-TSTh; to estimate the potential benefits to the UK of such exploitation; and to review the current status of H-TSTh technology. Despite limited involvement at present, it is concluded that the UK would be well placed with respect to longer term market opportunities if current developments by UK companies in fixed bowl technology and Stirling engines for dish Stirling system are successful. Opportunities also exist for turbine supply, civil contractors, insurance, finance and operation, but discussions with relevant UK companies has revealed only limited interest. (Author)

  2. The Study for Optimizing of the Electricity Power Supply in Central Java Province

    International Nuclear Information System (INIS)

    Herdinie, Sc S; Sudi-Ariyanto; Edi-Sartono; Suprapto; Nuryanti

    2004-01-01

    Electricity planning includes identification of electricity generation potential and problem where solution are being planned through the annual program. Due to correlation between electricity growth and economic growth, the sensitivity study for Central Java province has been done using three scenarios of annual electricity growth, i.e.: 6.7 %, 8 % and 10 % within the study period of 2003-2020. The tool used in this sensitivity study is WASP IV. From result the calculation gives total installed capacity in the end of study period for each electricity growth scenario are 3960 MW, 5500 MW and 8620 MW respectively. Total produced energy in the end of study period for each electricity growth scenario are 32301 G Wh, 39619 G Wh and 54374 G Wh. For total fuel required. Coal still predominate in all scenarios, followed by HSD and Gas. According to this study, Nuclear power plant can be introduced in 2020 for scenario of 8 % growth and 2017 for that of 10 % growth. WASP is utilized for projecting electricity supply. (author)

  3. Thermal effects of electrically conductive deposits in melter

    International Nuclear Information System (INIS)

    Choi, I.G.; Bickford, D.F.; Carter, J.T.

    1992-01-01

    The radioactive waste processed by the Defense Waste Processing Facility melter at the Savannah river Site contains noble metal fission-products. Operation of waste-glass melters treating commercial power reactor wastes indicates that accumulation of noble metals on melter floors can lead to distortion of electric heating patterns, loss of power, and possible electrode damage. Changes in melter geometry have been developed in Japan and Germany to minimize these effects. The two existing melters for the US Department of Energy's Defense Waste Processing Facility were designed in 1982, before this effect was known or had been characterized. Modeling and pilot scale tests are being conducted in the Integrated DWPF melter system to determine if the effect is significant for melters processing defense wastes, and if the effect can be diagnosed and corrected without significant damage or changes to the melter design. This document provides a discussion of these tests

  4. Electrical properties of thermally evaporated nickel-dimethylglyoxime thin films

    Science.gov (United States)

    Dakhel, A. A.; Ali-Mohamed Ahmed, Y.

    2005-06-01

    Thin Bis-(dimethylglyoximato)nickel(II) [Ni(DMG)2] films of amorphous and crystalline structures were prepared by vacuum deposition on Si (P) substrates. The films were characterised by X-ray fluorescence and X-ray diffraction. The constructed Al/Ni(DMG)2/Si(P) metal-insulator-semiconductor devices were characterised by the measurement of the gate-voltage dependence of their capacitance and ac conductance, from which the surface states density Dit of insulator/semiconductor interface and the density of the fixed charges in the oxide were determined. The ac electrical conduction and dielectric properties of the Ni(DMG)2-Silicon structure were studied at room temperature. The data of the ac measurements of the annealed films follow the correlated barrier-hopping CBH mode, from which the fundamental absorption bandgap, the minimum hopping distance, and other parameters of the model were determined.

  5. The thermal electrical properties of lithium sodium borate gasses

    International Nuclear Information System (INIS)

    Joshi, Anita R.; Bichile, G.K.

    2012-01-01

    Lithium sodium borate glasses with various composition have been prepared by melt quenching method. DSC studies were carried out. The glass transition temperature were found to decrease with alkali content in single alkali system and increase with second alkali content in mixed alkali system. The dc electrical conductivity has been measured as a function of temperature. The activation energy from the slope of the Arrhenius plots is calculated and it depends on the composition. In one set of single alkali glasses activation energies were found to increase with alkali content and in another set a single alkali system a transition from predominantly electronic to ionic conduction has been observed above 0.16 mol fraction of alkali content. The mixed alkali glasses have shown higher activation energies and lower conductivities. (author)

  6. The effect of thermal and radiation accelerated ageing on the A. C. electric motor parameters

    International Nuclear Information System (INIS)

    Pica, I.; Segarceanu, D.

    2000-01-01

    The paper presents the main aspects concerning the electric parameters variation of triphase asynchronous motors operating under specific environmental conditions determined by temperature, humidity, radiation. The testing of electric motor capability to meet and exceed the required performances all along its operating life implies the performing of thermal and radiation ageing while the motor is brought, in a relatively short time, under conditions equivalent to those at the end of its service life. The paper describes ageing and measurement techniques and the analyses of electric parameter behavior in these environmental simulated conditions. (author)

  7. Electric generator overhaul of the Ing. Carlos Ramirez Ulloa hydroelectric. Central project conclusions; Rehabilitacion de los generadores de la central hidroelectrica Ing. Carlos Ramirez Ulloa. Conclusiones del proyecto

    Energy Technology Data Exchange (ETDEWEB)

    Campuzano Martinez, Ignacio Roberto; Gonzalez Vazquez, Alejandro Esteban; Robles Pimentel, Edgar Guillermo; Esparza Saucedo, Marcos; Garcia Martinez, Javier; Sanchez Flores, Ernesto; Martinez Romero, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1999-12-31

    The Hydroelectric Ing. Carlos Ramirez Ulloa Power Central has three 200 MW electric generators. The Central initiated its commercial operation in 1985. The electric generators had design problems that were properly corrected in an overhaul program that was initiated in 1996, with Unit 2 electric generator and completed in 1998 with Unit 1 electric generator. This paper presents the relevant aspects of the experience accumulated in the project. [Espanol] La central hidroelectrica Ing. Carlos Ramirez Ulloa cuenta con tres generadores de 200 MW cada uno. La central inicio su operacion comercial en 1985. Los generadores tenian problemas de diseno que fueron debidamente corregidos en un programa de rehabilitacion que inicio en 1996, con el generador de la unidad 2, y culmino en 1998 con el generador de la unidad 1. En este articulo se presentan los aspectos relevantes de la experiencia acumulada en el proyecto.

  8. Electric generator overhaul of the Ing. Carlos Ramirez Ulloa hydroelectric. Central project conclusions; Rehabilitacion de los generadores de la central hidroelectrica Ing. Carlos Ramirez Ulloa. Conclusiones del proyecto

    Energy Technology Data Exchange (ETDEWEB)

    Campuzano Martinez, Ignacio Roberto; Gonzalez Vazquez, Alejandro Esteban; Robles Pimentel, Edgar Guillermo; Esparza Saucedo, Marcos; Garcia Martinez, Javier; Sanchez Flores, Ernesto; Martinez Romero, Jose Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-12-31

    The Hydroelectric Ing. Carlos Ramirez Ulloa Power Central has three 200 MW electric generators. The Central initiated its commercial operation in 1985. The electric generators had design problems that were properly corrected in an overhaul program that was initiated in 1996, with Unit 2 electric generator and completed in 1998 with Unit 1 electric generator. This paper presents the relevant aspects of the experience accumulated in the project. [Espanol] La central hidroelectrica Ing. Carlos Ramirez Ulloa cuenta con tres generadores de 200 MW cada uno. La central inicio su operacion comercial en 1985. Los generadores tenian problemas de diseno que fueron debidamente corregidos en un programa de rehabilitacion que inicio en 1996, con el generador de la unidad 2, y culmino en 1998 con el generador de la unidad 1. En este articulo se presentan los aspectos relevantes de la experiencia acumulada en el proyecto.

  9. Integrated energy and advanced thermal management system for hybrid electric vehicles

    NARCIS (Netherlands)

    Wei, C.

    2017-01-01

    Hybrid electric vehicles (HEVs) featuring a fuel source engine and an energy storage source battery play an important role in improving fuel efficiency compared with its conventional counterparts. In view of the drawbacks of the existing research neglecting the thermal aspects when it comes to

  10. 77 FR 11598 - Thermal Overload Protection for Electric Motors on Motor-Operated Valves

    Science.gov (United States)

    2012-02-27

    ... application of thermal overload protection devices that are integral with the motor starter for electric... Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: 301-251-7455; email... Development Branch, Division of Engineering, Office of Nuclear Regulatory Research. [FR Doc. 2012-4552 Filed 2...

  11. Thermal Energy Storage for Building Load Management: Application to Electrically Heated Floor

    Directory of Open Access Journals (Sweden)

    Hélène Thieblemont

    2016-07-01

    Full Text Available In cold climates, electrical power demand for space conditioning becomes a critical issue for utility companies during certain periods of the day. Shifting a portion or all of it to off-peak periods can help reduce peak demand and reduce stress on the electrical grid. Sensible thermal energy storage (TES systems, and particularly electrically heated floors (EHF, can store thermal energy in buildings during the off-peak periods and release it during the peak periods while maintaining occupants’ thermal comfort. However, choosing the type of storage system and/or its configuration may be difficult. In this paper, the performance of an EHF for load management is studied. First, a methodology is developed to integrate EHF in TRNSYS program in order to investigate the impact of floor assembly on the EHF performance. Then, the thermal comfort (TC of the night-running EHF is studied. Finally, indicators are defined, allowing the comparison of different EHF. Results show that an EHF is able to shift 84% of building loads to the night while maintaining acceptable TC in cold climate. Moreover, this system is able to provide savings for the customer and supplier if there is a significant difference between off-peak and peak period electricity prices.

  12. Thermal battery. [solid metal halide electrolytes with enhanced electrical conductance after a phase transition

    Science.gov (United States)

    Carlsten, R.W.; Nissen, D.A.

    1973-03-06

    The patent describes an improved thermal battery whose novel design eliminates various disadvantages of previous such devices. Its major features include a halide cathode, a solid metal halide electrolyte which has a substantially greater electrical conductance after a phase transition at some temperature, and a means for heating its electrochemical cells to activation temperature.

  13. Electrical and thermal conductivity of low temperature CVD graphene: the effect of disorder

    International Nuclear Information System (INIS)

    Vlassiouk, Ivan; Datskos, Panos; Smirnov, Sergei; Ivanov, Ilia; Hensley, Dale; Lavrik, Nickolay V; Fulvio, Pasquale F; Dai Sheng; Meyer, Harry; Chi Miaofang

    2011-01-01

    In this paper we present a study of graphene produced by chemical vapor deposition (CVD) under different conditions with the main emphasis on correlating the thermal and electrical properties with the degree of disorder. Graphene grown by CVD on Cu and Ni catalysts demonstrates the increasing extent of disorder at low deposition temperatures as revealed by the Raman peak ratio, I G /I D . We relate this ratio to the characteristic domain size, L a , and investigate the electrical and thermal conductivity of graphene as a function of L a . The electrical resistivity, ρ, measured on graphene samples transferred onto SiO 2 /Si substrates shows linear correlation with L a -1 . The thermal conductivity, K, measured on the same graphene samples suspended on silicon pillars, on the other hand, appears to have a much weaker dependence on L a , close to K ∼ L a 1/3 . It results in an apparent ρ ∼ K 3 correlation between them. Despite the progressively increasing structural disorder in graphene grown at lower temperatures, it shows remarkably high thermal conductivity (10 2 -10 3 W K -1 m -1 ) and low electrical (10 3 -3 x 10 5 Ω) resistivities suitable for various applications.

  14. Nanostructure design for drastic reduction of thermal conductivity while preserving high electrical conductivity.

    Science.gov (United States)

    Nakamura, Yoshiaki

    2018-01-01

    The design and fabrication of nanostructured materials to control both thermal and electrical properties are demonstrated for high-performance thermoelectric conversion. We have focused on silicon (Si) because it is an environmentally friendly and ubiquitous element. High bulk thermal conductivity of Si limits its potential as a thermoelectric material. The thermal conductivity of Si has been reduced by introducing grains, or wires, yet a further reduction is required while retaining a high electrical conductivity. We have designed two different nanostructures for this purpose. One structure is connected Si nanodots (NDs) with the same crystal orientation. The phonons scattering at the interfaces of these NDs occurred and it depended on the ND size. As a result of phonon scattering, the thermal conductivity of this nanostructured material was below/close to the amorphous limit. The other structure is Si films containing epitaxially grown Ge NDs. The Si layer imparted high electrical conductivity, while the Ge NDs served as phonon scattering bodies reducing thermal conductivity drastically. This work gives a methodology for the independent control of electron and phonon transport using nanostructured materials. This can bring the realization of thermoelectric Si-based materials that are compatible with large scale integrated circuit processing technologies.

  15. Photovoltaic. Solar thermal. Solar thermal electricity;Le Photovoltaique. Le solaire thermique. L'heliothermodynamique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The year 2008 was excellent for solar energy in the European Union. The growth of the installed capacity for photovoltaic was +159% (it means +4747.018 MW) to reach 9689.952 MW and that for solar thermal was +51.5% (it means +3172.5 MW) to reach 19982.7 MW. Worldwide concentrated solar thermal capacity stood at 679 MW in 2009, while this figure may seem low, the sector has a promising future ahead of it. (A.C.)

  16. Thermal Fluid-Dynamic Study for the thermal control of the new ALICE Central Detectors

    CERN Document Server

    AUTHOR|(CDS)2216237

    The Inner Tracking System Detector of the ALICE Experiment at CERN laboratory will be replaced in 2020 with a new Detector. It will have to provide, among others, higher spatial resolution, higher tracking precision and faster data read-out. These goals will be attained thanks to new pixel sensors chips and new electronic components, which will have a high impact in terms of dissipated heat. Therefore, one of the critical aspects for the success of the Upgrade project is the design of the Detector cooling system. This thesis work has been developed at CERN in Geneva in close contact with the group responsible for the Mechanics and Cooling of the Detector. The aim of the thermal fluid dynamic study devised is to deliver to the group a reliable and accurate description of the air flow inside the New Inner Tracking System Detector. After a first part of problem definition and design study, a Computational Fluid Dynamic (CFD) analysis has been developed with the ANSYS Fluent software. The CFD model built in this ...

  17. Integration of plug-in hybrid electric vehicles in a regional wind-thermal power system

    International Nuclear Information System (INIS)

    Goeransson, Lisa; Karlsson, Sten; Johnsson, Filip

    2010-01-01

    This study investigates consequences of integrating plug-in hybrid electric vehicles (PHEVs) in a wind-thermal power system supplied by one quarter of wind power and three quarters of thermal generation. Four different PHEV integration strategies, with different impacts on the total electric load profile, have been investigated. The study shows that PHEVs can reduce the CO 2 -emissions from the power system if actively integrated, whereas a passive approach to PHEV integration (i.e. letting people charge the car at will) is likely to result in an increase in emissions compared to a power system without PHEV load. The reduction in emissions under active PHEV integration strategies is due to a reduction in emissions related to thermal plant start-ups and part load operation. Emissions of the power sector are reduced with up to 4.7% compared to a system without PHEVs, according to the simulations. Allocating this emission reduction to the PHEV electricity consumption only, and assuming that the vehicles in electric mode is about 3 times as energy efficient as standard gasoline operation, total emissions from PHEVs would be less than half the emissions of a standard car, when running in electric mode.

  18. Critical success factors for BOT electric power projects in China: Thermal power versus wind power

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhen-Yu. [School of Business Administration, North China Electric Power University, Beijing 102206 (China); Zuo, Jian; Zillante, George [School of Natural and Built Environments, University of South Australia, Adelaide 5001 (Australia); Wang, Xin-Wei [Shandong Nuclear Power Equipment Manufacturing Co. Ltd, Haiyang, Shandong 265118 (China)

    2010-06-15

    Chinese electric power industry has adopted Build-Operate-Transfer (BOT) approach in a number of projects to alleviate the pressure of sole state-owned investment. The Chinese government has taken enormous efforts to create an environment to facilitate the application of BOT approach in electric power projects. Moreover, the growing attention on the sustainability issues puts the traditional major source of electricity - thermal power project under more strict scrutiny. As a result, various renewable energy projects, particularly the wind power projects have involved private sector funds. Both thermal power and wind power projects via BOT approach have met with a varying degree of success. Therefore, it is imperative to understand the factors contributing towards the success of both types of BOT power projects. Using an extensive literature survey, this paper identifies 31 success factors under 5 categories for Chinese BOT electric power projects. This is followed by a questionnaire survey to exam relative significance of these factors. The results reveal the different levels of significance of success factors for BOT thermal power projects versus wind power projects. Finally, survey results were analyzed to explore the underlying construction and distributions among the identified success factors. This study provides a valuable reference for all involved parties that are interested in developing BOT electric power projects in China. (author)

  19. Electro-thermal analysis of Lithium Iron Phosphate battery for electric vehicles

    Science.gov (United States)

    Saw, L. H.; Somasundaram, K.; Ye, Y.; Tay, A. A. O.

    2014-03-01

    Lithium ion batteries offer an attractive solution for powering electric vehicles due to their relatively high specific energy and specific power, however, the temperature of the batteries greatly affects their performance as well as cycle life. In this work, an empirical equation characterizing the battery's electrical behavior is coupled with a lumped thermal model to analyze the electrical and thermal behavior of the 18650 Lithium Iron Phosphate cell. Under constant current discharging mode, the cell temperature increases with increasing charge/discharge rates. The dynamic behavior of the battery is also analyzed under a Simplified Federal Urban Driving Schedule and it is found that heat generated from the battery during this cycle is negligible. Simulation results are validated with experimental data. The validated single cell model is then extended to study the dynamic behavior of an electric vehicle battery pack. The modeling results predict that more heat is generated on an aggressive US06 driving cycle as compared to UDDS and HWFET cycle. An extensive thermal management system is needed for the electric vehicle battery pack especially during aggressive driving conditions to ensure that the cells are maintained within the desirable operating limits and temperature uniformity is achieved between the cells.

  20. High efficiency particulate air filter technology from 1980 to 1985 in the Central Electricity Generating Board

    International Nuclear Information System (INIS)

    Skledon, R.; Taylor, S.; Fern, C.; Stead, M.

    1986-01-01

    This paper examines at the Central Electricity Generating Board's methods of High Efficiency Particulate Air (1,700 m 3 /hr) filter testing from conception to the present day. The choice of the test and the early results are looked at followed by the development using new test equipment for checking ladderframe systems. The need for the drawing up of the Central Electricity Generating Board 743401 Standard for filter manufacture and its effect on full implementation is looked into. The advantages and disadvantages of our test procedures are reflected upon and the future developments in test methods and filters for use by the C.E.G.B. in their power stations are discussed. (author)

  1. Tailoring of the electrical and thermal properties using ultra-short period non-symmetric superlattices

    Directory of Open Access Journals (Sweden)

    Paulina Komar

    2016-10-01

    Full Text Available Thermoelectric modules based on half-Heusler compounds offer a cheap and clean way to create eco-friendly electrical energy from waste heat. Here we study the impact of the period composition on the electrical and thermal properties in non-symmetric superlattices, where the ratio of components varies according to (TiNiSnn:(HfNiSn6−n, and 0 ⩽ n ⩽ 6 unit cells. The thermal conductivity (κ showed a strong dependence on the material content achieving a minimum value for n = 3, whereas the highest value of the figure of merit ZT was achieved for n = 4. The measured κ can be well modeled using non-symmetric strain relaxation applied to the model of the series of thermal resistances.

  2. Thermal and electrical energy management in a PEMFC stack - An analytical approach

    Energy Technology Data Exchange (ETDEWEB)

    Pandiyan, S.; Jayakumar, K.; Rajalakshmi, N.; Dhathathreyan, K.S. [Centre for Fuel Cell Technology, ARC International (ARCI), 120, Mambakkam Main Road, Medavakkam, Chennai 601 302 (India)

    2008-02-15

    An analytical method has been developed to differentiate the electrical and thermal resistance of the PEM fuel cell assembly in the fuel cell operating conditions. The usefulness of this method lies in the determination of the electrical resistance based on the polarization curve and the thermal resistance from the mass balance. This method also paves way for the evaluation of cogeneration from a PEMFC power plant. Based on this approach, the increase in current and resistance due to unit change in temperature at a particular current density has been evaluated. It was observed that the internal resistance of the cell is dependent on the electrode fabrication process, which also play a major role in the thermal management of the fuel cell stack. (author)

  3. Ocean thermal gradient as a generator of electricity. OTEC power plant

    Science.gov (United States)

    Enrique, Luna-Gomez Victor; Angel, Alatorre-Mendieta Miguel

    2016-04-01

    The OTEC (Ocean Thermal Energy Conversion) is a power plant that uses the thermal gradient of the sea water between the surface and a depth of about 700 meters. It works by supplying the heat to a steam machine, for evaporation, with sea water from the surface and cold, to condense the steam, with deep sea water. The energy generated by the power plant OTEC can be transferred to the electric power grid, another use is to desalinate seawater. During the twentieth century in some countries experimental power plants to produce electricity or obtaining drinking water they were installed. On the Mexico's coast itself this thermal gradient, as it is located in tropical seas it occurs, so it has possibilities of installing OTEC power plant type. In this paper one type OTEC power plant operation is represented in most of its components.

  4. Harvesting electrical energy from torsional thermal actuation driven by natural convection.

    Science.gov (United States)

    Kim, Shi Hyeong; Sim, Hyeon Jun; Hyeon, Jae Sang; Suh, Dongseok; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

    2018-06-07

    The development of practical, cost-effective systems for the conversion of low-grade waste heat to electrical energy is an important area of renewable energy research. We here demonstrate a thermal energy harvester that is driven by the small temperature fluctuations provided by natural convection. This harvester uses coiled yarn artificial muscles, comprising well-aligned shape memory polyurethane (SMPU) microfibers, to convert thermal energy to torsional mechanical energy, which is then electromagnetically converted to electrical energy. Temperature fluctuations in a yarn muscle, having a maximum hot-to-cold temperature difference of about 13 °C, were used to spin a magnetic rotor to a peak torsional rotation speed of 3,000 rpm. The electromagnetic energy generator converted the torsional energy to electrical energy, thereby producing an oscillating output voltage of up to 0.81 V and peak power of 4 W/kg, based on SMPU mass.

  5. Thermal and Electrical Conductivities of a Three-Dimensional Ideal Anyon Gas with Fractional Exclusion Statistics

    International Nuclear Information System (INIS)

    Qin Fang; Wen Wen; Chen Ji-Sheng

    2014-01-01

    The thermal and electrical transport properties of an ideal anyon gas within fractional exclusion statistics are studied. By solving the Boltzmann equation with the relaxation-time approximation, the analytical expressions for the thermal and electrical conductivities of a three-dimensional ideal anyon gas are given. The low-temperature expressions for the two conductivities are obtained by using the Sommerfeld expansion. It is found that the Wiedemann—Franz law should be modified by the higher-order temperature terms, which depend on the statistical parameter g for a charged anyon gas. Neglecting the higher-order terms of temperature, the Wiedemann—Franz law is respected, which gives the Lorenz number. The Lorenz number is a function of the statistical parameter g. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  6. Numerical Model and Experimental Analysis of the Thermal Behavior of Electric Radiant Heating Panels

    Directory of Open Access Journals (Sweden)

    Giovanni Ferrarini

    2018-01-01

    Full Text Available Electric radiant heating panels are frequently selected during the design phase of residential and industrial heating systems, especially for retrofit of existing buildings, as an alternative to other common heating systems, such as radiators or air conditioners. The possibility of saving living and working space and the ease of installation are the main advantages of electric radiant solutions. This paper investigates the thermal performance of a typical electric radiant panel. A climatic room was equipped with temperature sensors and heat flow meters to perform a steady state experimental analysis. For the dynamic behavior, a mathematical model was created and compared to a thermographic measurement procedure. The results showed for the steady state an efficiency of energy transformation close to one, while in a transient thermal regime the time constant to reach the steady state condition was slightly faster than the typical ones of hydronic systems.

  7. Influence of crystal field excitations on thermal and electrical resistivity of normal rare-earth metals

    Energy Technology Data Exchange (ETDEWEB)

    Durczewski, K.; Gajek, Z.; Mucha, J. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wroclaw (Poland)

    2014-11-15

    A simple formula describing the influence of the crystalline electric field free-ion excitations on the temperature dependence of the contribution of the s-f scattering to the thermal resistivity of normal rare-earth metals is presented. The corresponding formula for the electrical resistivity is also given and compared to the one being currently used. Theoretical electron-phonon scattering contributions derived in earlier papers and constant impurity scattering contributions are added to the derived s-f contribution formulae in order to fit the total electrical and thermal resistivity represented as functions of the temperature to experimental dependences on the temperature for DyIn{sub 3} and in this way to manifest applicability of the derived formulae to real materials. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Influence of crystal field excitations on thermal and electrical resistivity of normal rare-earth metals

    International Nuclear Information System (INIS)

    Durczewski, K.; Gajek, Z.; Mucha, J.

    2014-01-01

    A simple formula describing the influence of the crystalline electric field free-ion excitations on the temperature dependence of the contribution of the s-f scattering to the thermal resistivity of normal rare-earth metals is presented. The corresponding formula for the electrical resistivity is also given and compared to the one being currently used. Theoretical electron-phonon scattering contributions derived in earlier papers and constant impurity scattering contributions are added to the derived s-f contribution formulae in order to fit the total electrical and thermal resistivity represented as functions of the temperature to experimental dependences on the temperature for DyIn 3 and in this way to manifest applicability of the derived formulae to real materials. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Thermal Performance of Traditional House in the Upland Central Celebes of Indonesia

    Directory of Open Access Journals (Sweden)

    Sri Nastiti N.E Nastiti N.E

    2011-11-01

    Full Text Available House presents special problems for design in relation to climate as it accommodates variety of uses over 24-hour period. It is widely known in the tropical countries that traditional houses are more sensitive to the prevailing climate and able to provide comfortable internal environment for the occupants. Tambi as one of traditional houses in upland Central Celebes Indonesia is believed to be thermally comfortable, yet there still no empirical evidence to approve it. Present study conducted empirical studies on typical traditional Tambi houses to evaluate their thermal performance. External and internal climatic conditions were measured in each house and were analysed. Results of the study showed that typical traditional Tambi house are not able to maintain the internal temperature within the comfort range for a preiod of 24- hours. Thermal quality of the house, however, were improving as indicated by internal temperatures which were more satisfactory than the external temperatures.

  10. External electric field driving the ultra-low thermal conductivity of silicene.

    Science.gov (United States)

    Qin, Guangzhao; Qin, Zhenzhen; Yue, Sheng-Ying; Yan, Qing-Bo; Hu, Ming

    2017-06-01

    The manipulation of thermal transport is in increasing demand as heat transfer plays a critical role in a wide range of practical applications, such as efficient heat dissipation in nanoelectronics and heat conduction hindering in solid-state thermoelectrics. It is well established that the thermal transport in semiconductors and insulators (phonons) can be effectively modulated by structure engineering or materials processing. However, almost all the existing approaches involve altering the original atomic structure of materials, which would be hindered due to either irreversible structure change or limited tunability of thermal conductivity. Motivated by the inherent relationship between phonon behavior and interatomic electrostatic interaction, we comprehensively investigate the effect of external electric field, a widely used gating technique in modern electronics, on the lattice thermal conductivity (κ). Taking two-dimensional silicon (silicene) as a model, we demonstrate that by applying an electric field (E z = 0.5 V Å -1 ) the κ of silicene can be reduced to a record low value of 0.091 W m -1 K -1 , which is more than two orders of magnitude lower than that without an electric field (19.21 W m -1 K -1 ) and is even comparable to that of the best thermal insulation materials. Fundamental insights are gained from observing the electronic structures. With an electric field applied, due to the screened potential resulting from the redistributed charge density, the interactions between silicon atoms are renormalized, leading to phonon renormalization and the modulation of phonon anharmonicity through electron-phonon coupling. Our study paves the way for robustly tuning phonon transport in materials without altering the atomic structure, and would have significant impact on emerging applications, such as thermal management, nanoelectronics and thermoelectrics.

  11. High frequency electrical stimulation concurrently induces central sensitization and ipsilateral inhibitory pain modulation.

    Science.gov (United States)

    Vo, L; Drummond, P D

    2013-03-01

    In healthy humans, analgesia to blunt pressure develops in the ipsilateral forehead during various forms of limb pain. The aim of the current study was to determine whether this analgesic response is induced by ultraviolet B radiation (UVB), which evokes signs of peripheral sensitization, or by high-frequency electrical stimulation (HFS), which triggers signs of central sensitization. Before and after HFS and UVB conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the treated site in the forearm. In addition, sensitivity to blunt pressure was measured bilaterally in the forehead. The effect of ipsilateral versus contralateral temple cooling on electrically evoked pain in the forearm was then examined, to determine whether HFS or UVB conditioning altered inhibitory pain modulation. UVB conditioning triggered signs of peripheral sensitization, whereas HFS conditioning triggered signs of central sensitization. Importantly, ipsilateral forehead analgesia developed after HFS but not UVB conditioning. In addition, decreases in electrically evoked pain at the HFS-treated site were greater during ipsilateral than contralateral temple cooling, whereas decreases at the UVB-treated site were similar during both procedures. HFS conditioning induced signs of central sensitization in the forearm and analgesia both in the ipsilateral forehead and the HFS-treated site. This ipsilateral analgesia was not due to peripheral sensitization or other non-specific effects, as it failed to develop after UVB conditioning. Thus, the supra-spinal mechanisms that evoke central sensitization might also trigger a hemilateral inhibitory pain modulation process. This inhibitory process could sharpen the boundaries of central sensitization or limit its spread. © 2012 European Federation of International Association for the Study of Pain Chapters.

  12. A thermally regenerative ammonia-based battery for efficient harvesting of low-grade thermal energy as electrical power

    KAUST Repository

    Zhang, Fang

    2015-01-01

    © 2015 The Royal Society of Chemistry. Thermal energy was shown to be efficiently converted into electrical power in a thermally regenerative ammonia-based battery (TRAB) using copper-based redox couples [Cu(NH3)4 2+/Cu and Cu(ii)/Cu]. Ammonia addition to the anolyte (2 M ammonia in a copper-nitrate electrolyte) of a single TRAB cell produced a maximum power density of 115 ± 1 W m-2 (based on projected area of a single copper mesh electrode), with an energy density of 453 W h m-3 (normalized to the total electrolyte volume, under maximum power production conditions). Adding a second cell doubled both the voltage and maximum power. Increasing the anolyte ammonia concentration to 3 M further improved the maximum power density to 136 ± 3 W m-2. Volatilization of ammonia from the spent anolyte by heating (simulating distillation), and re-addition of this ammonia to the spent catholyte chamber with subsequent operation of this chamber as the anode (to regenerate copper on the other electrode), produced a maximum power density of 60 ± 3 W m-2, with an average discharge energy efficiency of ∼29% (electrical energy captured versus chemical energy in the starting solutions). Power was restored to 126 ± 5 W m-2 through acid addition to the regenerated catholyte to decrease pH and dissolve Cu(OH)2 precipitates, suggesting that an inexpensive acid or a waste acid could be used to improve performance. These results demonstrated that TRABs using ammonia-based electrolytes and inexpensive copper electrodes can provide a practical method for efficient conversion of low-grade thermal energy into electricity.

  13. Analysis of thermal characteristics of electrical wiring for load groups in cattle barns.

    Science.gov (United States)

    Kim, Doo Hyun; Yoo, Sang-Ok; Kim, Sung Chul; Hwang, Dong Kyu

    2015-01-01

    The purpose of the current study is to analyze the thermal characteristics of electrical wirings depending on the number of operating load by connecting four types of electrical wirings that are selected by surveying the conditions for the electric fans, automatic waterers and halogen warm lamps that were installed in cattle barns in different years. The conditions of 64 cattle barns were surveyed and an experimental test was conducted at a cattle barn. The condition-survey covered inappropriate design, construction and misuse of electrical facility, including electrical wiring mostly used, and the mode of load current was evaluated. The survey showed that the mode of load current increased as the installation year of the fans, waterers and halogen lamps became older. Accordingly, the cattle barn manager needed to increase the capacity of the circuit breaker, which promoted the degradation of insulation of the electrical wires' sheath and increased possibility for electrical fires in the long-run. The test showed that the saturation temperature of the wire insulated sheath increased depending on the installation year of the load groups, in case of VCTFK and VFF electric wires, therefore, requiring their careful usage in the cattle barns.

  14. Mechanical, Thermal, and Electrical Energy Storage in a Single Working Body: Electrification and Thermal Effects upon Pressure-Induced Water Intrusion-Extrusion in Nanoporous Solids.

    Science.gov (United States)

    Grosu, Yaroslav; Mierzwa, Michał; Eroshenko, Valentine A; Pawlus, Sebastian; Chorażewski, Mirosław; Nedelec, Jean-Marie; Grolier, Jean-Pierre E

    2017-03-01

    This paper presents the first experimental evidence of pronounced electrification effects upon reversible cycle of forced water intrusion-extrusion in nanoporous hydrophobic materials. Recorded generation of electricity combined with high-pressure calorimetric measurements improves the energy balance of {nanoporous solid + nonwetting liquid} systems by compensating mechanical and thermal energy hysteresis in the cycle. Revealed phenomena provide a novel way of "mechanical to electrical" and/or "thermal to electrical" energy transformation with unprecedented efficiency and additionally open a perspective to increase the efficiency of numerous energy applications based on such systems taking advantage of electricity generation during operational cycle.

  15. Thermal pulse measurements of space charge distributions under an applied electric field in thin films

    International Nuclear Information System (INIS)

    Zheng, Feihu; An, Zhenlian; Zhang, Yewen; Liu, Chuandong; Lin, Chen; Lei, Qingquan

    2013-01-01

    The thermal pulse method is a powerful method to measure space charge and polarization distributions in thin dielectric films, but a complicated calibration procedure is necessary to obtain the real distribution. In addition, charge dynamic behaviour under an applied electric field cannot be observed by the classical thermal pulse method. In this work, an improved thermal pulse measuring system with a supplemental circuit for applying high voltage is proposed to realize the mapping of charge distribution in thin dielectric films under an applied field. The influence of the modified measuring system on the amplitude and phase of the thermal pulse response current are evaluated. Based on the new measuring system, an easy calibration approach is presented with some practical examples. The newly developed system can observe space charge evolution under an applied field, which would be very helpful in understanding space charge behaviour in thin films. (paper)

  16. Effect of thermal insulation on the electrical characteristics of NbOx threshold switches

    Science.gov (United States)

    Wang, Ziwen; Kumar, Suhas; Wong, H.-S. Philip; Nishi, Yoshio

    2018-02-01

    Threshold switches based on niobium oxide (NbOx) are promising candidates as bidirectional selector devices in crossbar memory arrays and building blocks for neuromorphic computing. Here, it is experimentally demonstrated that the electrical characteristics of NbOx threshold switches can be tuned by engineering the thermal insulation. Increasing the thermal insulation by ˜10× is shown to produce ˜7× reduction in threshold current and ˜45% reduction in threshold voltage. The reduced threshold voltage leads to ˜5× reduction in half-selection leakage, which highlights the effectiveness of reducing half-selection leakage of NbOx selectors by engineering the thermal insulation. A thermal feedback model based on Poole-Frenkel conduction in NbOx can explain the experimental results very well, which also serves as a piece of strong evidence supporting the validity of the Poole-Frenkel based mechanism in NbOx threshold switches.

  17. Smart thermal grid with integration of distributed and centralized solar energy systems

    International Nuclear Information System (INIS)

    Yang, Libing; Entchev, Evgueniy; Rosato, Antonio; Sibilio, Sergio

    2017-01-01

    Smart thermal grids (STGs) are able to perform the same function as classical grids, but are developed in order to make better use of distributed, possibly intermittent, thermal energy resources and to provide the required energy when needed through efficient resources utilization and intelligent management. District heating (DH) plays a significant role in the implementation of future smart energy systems. To fulfil its role, DH technologies must be further developed to integrate renewable resources, create low-temperature networks, and consequently to make existing or new DH networks ready for integration into future STGs. Solar heating is a promising option for low-temperature DH systems. Thermal energy storage (TES) can make the availability of the energy supply match the demand. An integration of centralized seasonal and distributed short-term thermal storages would facilitate an efficient recovery of the solar energy. This study, through modelling and simulation, investigates the impacts of such integration on the overall performance of a community-level solar DH system. The performance analysis results show that the solar DH system with integration of distributed and centralized seasonal TESs improves system overall efficiency, and reduces DH network heat losses, primary energy consumption and greenhouse gas emissions, in comparison to the one without integration. - Highlights: • STG should be designed to store energy in the most efficient way at the most effective location. • Integration of centralized seasonal and distributed TESs in a solar DH system is proposed. • Performance of such integrated solar DH system is evaluated and compared to the one without. • The integration results in reduction of primary energy consumption and GHG emission. • The integration improves the overall efficiency of the total solar energy system.

  18. The Electrical and Thermal Conductivity of Woven Pristine and Intercalated Graphite Fiber-Polymer Composites

    Science.gov (United States)

    Gaier, James R.; Vandenburg, Yvonne Yoder; Berkebile, Steven; Stueben, Heather; Balagadde, Frederick

    2002-01-01

    A series of woven fabric laminar composite plates and narrow strips were fabricated from a variety of pitch-based pristine and bromine intercalated graphite fibers in an attempt to determine the influence of the weave on the electrical and thermal conduction. It was found generally that these materials can be treated as if they are homogeneous plates. The rule of mixtures describes the resistivity of the composite fairly well if it is realized that only the component of the fibers normal to the equipotential surface will conduct current. When the composite is narrow with respect to the fiber weave, however, there is a marked angular dependence of the resistance which was well modeled by assuming that the current follows only along the fibers (and not across them in a transverse direction), and that the contact resistance among the fibers in the composite is negligible. The thermal conductivity of composites made from less conductive fibers more closely followed the rule of mixtures than that of the high conductivity fibers, though this is thought to be an artifact of the measurement technique. Electrical and thermal anisotropy could be induced in a particular region of the structure by weaving together high and low conductivity fibers in different directions, though this must be done throughout all of the layers of the structure as interlaminar conduction precludes having only the top layer carry the anisotropy. The anisotropy in the thermal conductivity is considerably less than either that predicted by the rule of mixtures or the electrical resistivity.

  19. Combined simulation of energy and thermal management for an electric vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Mohrmann, Bjoern; Jeck, Peter [Institut fuer Kraftfahrzeuge Aachen (Germany); Simon, Carsten [fortiss GmbH, Muenchen (Germany); Ungermann, Jochen [Audi AG, Ingolstadt (Germany)

    2012-11-01

    The project eperformance, which is funded by the BMBF, is conducted by project partners from RWTH Aachen, Audi, Bosch Engineering and fortiss GmbH, in order to demonstrate the concept of an electric vehicle on the basis of a holistic development approach. To support this, several simulation platforms come into use, i.e. CFD Simulation for cooling concepts, electromagnetic simulations for electric machine design, physical simulation of cooling circuits as well as vehicle mechanics and controller design. To develop an energy efficient vehicle management, some of these simulation domains have to be combined, to simulate interdependencies between for example usage of high-voltage batteries, their thermal response and the impact for controller strategies. Within the project it was decided to use the Tool TISC (TLK Inter Software Connector) to combine as well a physical model, based on Modelica/Dymola to simulate thermal behaviours of components with a longitudinal vehicle model and a controller model, both based in MATLAB/Simulink. Advantages of such a coupled simulation are the re-usability of existing models in both tools with their tool-specific benefits as well as the possibility to cluster the models on different computers. The article will explain how the combined simulation is set up and parameterized, and will show two use cases: the thermal management of the two independent battery systems of the demonstrator vehicle and the torque distribution on the three electric machines in the vehicle, depending on the drive situation and the thermal state of the machines. (orig)

  20. Qualitative thermal characterization and cooling of lithium batteries for electric vehicles

    Science.gov (United States)

    Mariani, A.; D'Annibale, F.; Boccardi, G.; Celata, G. P.; Menale, C.; Bubbico, R.; Vellucci, F.

    2014-04-01

    The paper deals with the cooling of batteries. The first step was the thermal characterization of a single cell of the module, which consists in the detection of the thermal field by means of thermographic tests during electric charging and discharging. The purpose was to identify possible critical hot points and to evaluate the cooling demand during the normal operation of an electric car. After that, a study on the optimal configuration to obtain the flattening of the temperature profile and to avoid hot points was executed. An experimental plant for cooling capacity evaluation of the batteries, using air as cooling fluid, was realized in our laboratory in ENEA Casaccia. The plant is designed to allow testing at different flow rate and temperatures of the cooling air, useful for the assessment of operative thermal limits in different working conditions. Another experimental facility was built to evaluate the thermal behaviour changes with water as cooling fluid. Experimental tests were carried out on the LiFePO4 batteries, under different electric working conditions using the two loops. In the future, different type of batteries will be tested and the influence of various parameters on the heat transfer will be assessed for possible optimal operative solutions.

  1. Qualitative thermal characterization and cooling of lithium batteries for electric vehicles

    International Nuclear Information System (INIS)

    Mariani, A; D'Annibale, F; Boccardi, G; Celata, G P; La Sapienza (Italy))" data-affiliation=" (University of Roma La Sapienza (Italy))" >Menale, C; La Sapienza (Italy))" data-affiliation=" (University of Roma La Sapienza (Italy))" >Bubbico, R; Vellucci, F

    2014-01-01

    The paper deals with the cooling of batteries. The first step was the thermal characterization of a single cell of the module, which consists in the detection of the thermal field by means of thermographic tests during electric charging and discharging. The purpose was to identify possible critical hot points and to evaluate the cooling demand during the normal operation of an electric car. After that, a study on the optimal configuration to obtain the flattening of the temperature profile and to avoid hot points was executed. An experimental plant for cooling capacity evaluation of the batteries, using air as cooling fluid, was realized in our laboratory in ENEA Casaccia. The plant is designed to allow testing at different flow rate and temperatures of the cooling air, useful for the assessment of operative thermal limits in different working conditions. Another experimental facility was built to evaluate the thermal behaviour changes with water as cooling fluid. Experimental tests were carried out on the LiFePO4 batteries, under different electric working conditions using the two loops. In the future, different type of batteries will be tested and the influence of various parameters on the heat transfer will be assessed for possible optimal operative solutions.

  2. Thermal and electrical energy yield analysis of a directly water cooled photovoltaic module

    Directory of Open Access Journals (Sweden)

    Mtunzi Busiso

    2016-01-01

    Full Text Available Electrical energy of photovoltaic modules drops by 0.5% for each degree increase in temperature. Direct water cooling of photovoltaic modules was found to give improved electrical and thermal yield. A prototype was put in place to analyse the field data for a period of a year. The results showed an initial high performance ratio and electrical power output. The monthly energy saving efficiency of the directly water cooled module was found to be approximately 61%. The solar utilisation of the naturally cooled photovoltaic module was found to be 8.79% and for the directly water cooled module its solar utilisation was 47.93%. Implementation of such systems on households may reduce the load from the utility company, bring about huge savings on electricity bills and help in reducing carbon emissions.

  3. Integration and Validation of a Thermal Energy Storage System for Electric Vehicle Cabin Heating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyu [MAHLE Behr Troy Inc.; Craig, Timothy [MAHLE Behr Troy Inc.; Wolfe, Edward [MAHLE Behr Troy Inc.; LaClair, Tim J. [ORNL; Gao, Zhiming [ORNL; Levin, Michael [Ford Motor Company; Demitroff, Danrich [Ford Motor Company; Shaikh, Furqan [Ford Motor Company

    2017-03-01

    It is widely recognized in the automotive industry that, in very cold climatic conditions, the driving range of an Electric Vehicle (EV) can be reduced by 50% or more. In an effort to minimize the EV range penalty, a novel thermal energy storage system has been designed to provide cabin heating in EVs and Plug-in Hybrid Electric Vehicles (PHEVs) by using an advanced phase change material (PCM). This system is known as the Electrical PCM-based Thermal Heating System (ePATHS) [1, 2]. When the EV is connected to the electric grid to charge its traction battery, the ePATHS system is also “charged” with thermal energy. The stored heat is subsequently deployed for cabin comfort heating during driving, for example during commuting to and from work.The ePATHS system, especially the PCM heat exchanger component, has gone through substantial redesign in order to meet functionality and commercialization requirements. The final system development for EV implementation has occurred on a mid-range EV and has been evaluated for its capability to extend the driving range. Both simulated driving in a climatic tunnel and actual road testing have been carried out. The ePATHS has demonstrated its ability to supply the entire cabin heating needs for a round trip commute totaling 46 minutes, including 8 hours of parking, at an ambient temperature of -10°C.

  4. Enhanced thermoelectric efficiency via orthogonal electrical and thermal conductances in phosphorene.

    Science.gov (United States)

    Fei, Ruixiang; Faghaninia, Alireza; Soklaski, Ryan; Yan, Jia-An; Lo, Cynthia; Yang, Li

    2014-11-12

    Thermoelectric devices that utilize the Seebeck effect convert heat flow into electrical energy and are highly desirable for the development of portable, solid state, passively powered electronic systems. The conversion efficiencies of such devices are quantified by the dimensionless thermoelectric figure of merit (ZT), which is proportional to the ratio of a device's electrical conductance to its thermal conductance. In this paper, a recently fabricated two-dimensional (2D) semiconductor called phosphorene (monolayer black phosphorus) is assessed for its thermoelectric capabilities. First-principles and model calculations reveal not only that phosphorene possesses a spatially anisotropic electrical conductance, but that its lattice thermal conductance exhibits a pronounced spatial-anisotropy as well. The prominent electrical and thermal conducting directions are orthogonal to one another, enhancing the ratio of these conductances. As a result, ZT may reach the criterion for commercial deployment along the armchair direction of phosphorene at T = 500 K and is close to 1 even at room temperature given moderate doping (∼2 × 10(16) m(-2) or 2 × 10(12) cm(-2)). Ultimately, phosphorene hopefully stands out as an environmentally sound thermoelectric material with unprecedented qualities. Intrinsically, it is a mechanically flexible material that converts heat energy with high efficiency at low temperatures (∼300 K), one whose performance does not require any sophisticated engineering techniques.

  5. Effect of electrical pulse treatment on the thermal fatigue resistance of bionic compacted graphite cast iron processed in water

    International Nuclear Information System (INIS)

    Liu, Yan; Zhou, Hong; Su, Hang; Yang, Chunyan; Cheng, Jingyan; Zhang, Peng; Ren, Luquan

    2012-01-01

    Highlights: ► Electrical pulse treatment can reduce cracks on bionic units before thermal fatigue tests. ► Electrical pulse treatment can reduce crack sources during thermal fatigue tests. ► Thermal fatigue resistance of bionic units processed in water is enhanced. ► Thermal fatigue resistance of bionic CGI processed in water is improved. -- Abstract: In order to further enhance the thermal fatigue resistance of bionic compacted graphite cast iron (CGI) which is processed by laser in water, the electrical pulse treatment is applied to improve the thermal fatigue resistance of bionic units. The results show that the electrical pulse treatment causes the supersaturated carbon atoms located in the lattice of austenite to react with the iron atoms to form the Fe 3 C. The microstructures of the bionic units processed in water are refined by the electrical pulse treatment. The cracks on the bionic units are reduced by the electrical pulse treatment before the thermal fatigue tests; and during the tests, the thermal fatigue resistance of bionic units is therefore enhanced by reducing the crack sources. By this way, the thermal fatigue resistance of bionic CGI processed in water is improved.

  6. The Staffing of Central Electricity Generating Board Nuclear Power Stations; Organigramme des centrales nucleaires du central electricity generating board; Politika v oblasti kadrov na atomnykh ehlektrostantsiyakh CEGB; El personal de las plantas nucleoelectricas de la central electricity generating board.

    Energy Technology Data Exchange (ETDEWEB)

    Bartlett, J. S.; Shepherd, G. T. [Central Electricity Generating Board, Western Division, Bristol (United Kingdom)

    1963-10-15

    An account is given of the staffing requirements and organization at a CEBG nuclear power station. The training of staff and licensing requirements for reactoroperating staff are discussed. Experience gained to data of the outcome of pre-operating training and detailed planning in the operational sphere is given. (author) [French] Le memoire donne un apercu de l'organigramme d'une centrale nucleaire du CEGB et des conditions auxquelles doit satisfaire le personnel (formation, qualifications requises pour la fonction d'operateur). Il rend compte egalement de l'experience acquise a ce jour quant a l'interet qu'il y a a former le personnel au prealable et a etablir des plans d'operation detailles. (author) [Spanish] La memoria informa sobre la organizacion de las centrales nucleoelectricas de la CEGB y sobre la plantilla de personal que estas requieren. Discute la formacion del personal y los requisitos para obtener la licencia de operador de reactores. Describe la experiencia adquirida hasta el presente en materia de formacion previa del personal y de organizacion detallada de las operaciones. (author) [Russian] Daetsya otchet o trebovaniyakh, pred{sup y}avlyaemykh k personalu, i organizatsiya nabora personala na atomnykh ehlektrostantsiyakh Tsentral'nogo upravleniya proizvodstva ehlektroehnergii (CEGB). Obsuzhdayutsya voprosy podgotovki personala i normativnykh trebovanij, pred{sup y}avlyaemykh k ehkspluatatsionnomu personalu. Izlagaetsya opyt, nakoplennyj k nastoyashchemu vremeni v rezul'tate osushchestvleniya predehkspluatatsionnoj podgotovki i podrobnogo planirovaniya v usloviyakh ehkspluatatsii. (author)

  7. Design and Testing of a Thermal Storage System for Electric Vehicle Cabin Heating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyu [MAHLE Behr Troy Inc.; WolfeIV, Edward [MAHLE Behr Troy Inc.; Craig, Timothy [MAHLE Behr Troy Inc.; LaClair, Tim J [ORNL; Gao, Zhiming [ORNL; Abdelaziz, Omar [ORNL

    2016-01-01

    Without the waste heat available from the engine of a conventional automobile, electric vehicles (EVs) must provide heat to the cabin for climate control using energy stored in the vehicle. In current EV designs, this energy is typically provided by the traction battery. In very cold climatic conditions, the power required to heat the EV cabin can be of a similar magnitude to that required for propulsion of the vehicle. As a result, the driving range of an EV can be reduced very significantly during winter months, which limits consumer acceptance of EVs and results in increased battery costs to achieve a minimum range while ensuring comfort to the EV driver. To minimize the range penalty associated with EV cabin heating, a novel climate control system that includes thermal energy storage has been designed for use in EVs and plug-in hybrid electric vehicles (PHEVs). The system uses the stored latent heat of an advanced phase change material (PCM) to provide cabin heating. The PCM is melted while the EV is connected to the electric grid for charging of the electric battery, and the stored energy is subsequently transferred to the cabin during driving. To minimize thermal losses when the EV is parked for extended periods, the PCM is encased in a high performance insulation system. The electrical PCM-Assisted Thermal Heating System (ePATHS) was designed to provide enough thermal energy to heat the EV s cabin for approximately 46 minutes, covering the entire daily commute of a typical driver in the U.S.

  8. Accelerated thermal and radiation-oxidation combined degradation of electric cable insulation materials

    International Nuclear Information System (INIS)

    Yagi, Toshiaki; Seguchi, Tadao; Yoshida, Kenzo

    1986-03-01

    For the development of accelerated testing methodology to estimate the life time of electric cable, which is installed in radiation field such as a nuclear reactor containment vessel, radiation and thermal combined degradation of cable insulation and jacketing materials was studied. The materials were two types of formulated polyethylene, ethylene-propylene rubber, Hypalon, and Neoprene. With Co-60 γ-rays the materials were irradiated up to 0.5 MGy under vacuum and in oxygen under pressure, then exposed to thermal aging at elevated temperature in oxygen. The degradation was investigated by the tensile test, gelfraction, and swelling measurements. The thermal degradation rate for each sample increases with increase of oxygen concentration, i.e. oxygen pressure, during the aging, and tends to saturate above 0.2 MPa of oxygen pressure. Then, the effects of irradiation and the temperature on the thermal degradation rate were investigated at the oxygen pressure of 0.2 MPa in the temperature range from 110 deg C to 150 deg C. For all of samples irradiated in oxygen, the following thermal degradation rate was accelerated by several times comparing with unirradiated samples, while the rate of thermal degradation for the sample except Neoprene irradiated under vacuum was nearly equal to that of unirradiated one. By the analysis of thermal degradation rate against temperature using Arrhenius equation, it was found that the activation energy tends to decrease for the samples irradiated in oxidation condition. (author)

  9. Thermal transport of carbon nanotubes and graphene under optical and electrical heating measured by Raman spectroscopy

    Science.gov (United States)

    Hsu, I.-Kai

    This thesis presents systematic studies of thermal transport in individual single walled carbon nanotubes (SWCNTs) and graphene by optical and electrical approaches using Raman spectroscopy. In the work presented from Chapter 2 to Chapter 6, individual suspended CNTs are preferentially measured in order to explore their intrinsic thermal properties. Moreover, the Raman thermometry is developed to detect the temperature of the carbon nanotube (CNT). A parabolic temperature profile is observed in the suspended region of the CNT while a heating laser scans across it, providing a direct evidence of diffusive thermal transport in an individual suspended CNT. Based on the curvature of the temperature profile, we can solve for the ratio of thermal contact resistance to the thermal resistance of the CNT, which spans the range from 0.02 to 17. The influence of thermal contact resistance on the thermal transport in an individual suspended CNT is also studied. The Raman thermometry is carried out in the center of a CNT, while its contact length is successively shortened by an atomic force microscope (AFM) tip cutting technique. By investigating the dependence of the CNT temperature on its thermal contact length, the temperature of a CNT is found to increase dramatically as the contact length is made shorter. This work reveals the importance of manipulating the CNT thermal contact length when adopting CNT as a thermal management material. In using a focused laser to induce heating in a suspended CNT, one open question that remains unanswered is how many of the incident photons are absorbed by the CNT of interest. To address this question, micro-fabricated platinum thermometers, together with micro-Raman spectroscopy are used to quantify the optical absorption of an individual CNT. The absorbed power in the CNT is equal to the power detected by two thermometers at the end of the CNT. Our result shows that the optical absorption lies in the range between 0.03 to 0.44%. In

  10. Technological drivers in data centers and telecom systems: Multiscale thermal, electrical, and energy management

    International Nuclear Information System (INIS)

    Garimella, Suresh V.; Persoons, Tim; Weibel, Justin; Yeh, Lian-Tuu

    2013-01-01

    Highlights: ► Thermal management approaches reviewed against energy usage of IT industry. ► Challenges of energy efficiency in large-scale electronic systems highlighted. ► Underlying drivers for progress at the business and technology levels identified. ► Thermal, electrical and energy management challenges discussed as drivers. ► Views of IT system operators, manufacturers and integrators represented. - Abstract: We identify technological drivers for tomorrow’s data centers and telecommunications systems, including thermal, electrical and energy management challenges, based on discussions at the 2nd Workshop on Thermal Management in Telecommunication Systems and Data Centers in Santa Clara, California, on April 25–26, 2012. The relevance of thermal management in electronic systems is reviewed against the background of the energy usage of the information technology (IT) industry, encompassing perspectives of different sectors of the industry. The underlying drivers for progress at the business and technology levels are identified. The technological challenges are reviewed in two main categories – immediate needs and future needs. Enabling cooling techniques that are currently under development are also discussed

  11. Thermal modelling of Li-ion polymer battery for electric vehicle drive cycles

    Science.gov (United States)

    Chacko, Salvio; Chung, Yongmann M.

    2012-09-01

    Time-dependent, thermal behaviour of a lithium-ion (Li-ion) polymer cell has been modelled for electric vehicle (EV) drive cycles with a view to developing an effective battery thermal management system. The fully coupled, three-dimensional transient electro-thermal model has been implemented based on a finite volume method. To support the numerical study, a high energy density Li-ion polymer pouch cell was tested in a climatic chamber for electric load cycles consisting of various charge and discharge rates, and a good agreement was found between the model predictions and the experimental data. The cell-level thermal behaviour under stressful conditions such as high power draw and high ambient temperature was predicted with the model. A significant temperature increase was observed in the stressful condition, corresponding to a repeated acceleration and deceleration, indicating that an effective battery thermal management system would be required to maintain the optimal cell performance and also to achieve a full battery lifesapn.

  12. Mechatronics design and experimental verification of an electric-vehicle-based hybrid thermal management system

    Directory of Open Access Journals (Sweden)

    Yi-Hsuan Hung

    2016-02-01

    Full Text Available In this study, an electric-vehicle-based thermal management system was designed for dual energy sources. An experimental platform developed in a previous study was modified. Regarding the mechanical components, a heat exchanger with a radiator, proportional valve, coolant pipes, and coolant pump was appropriately integrated. Regarding the electric components, two heaters emulating waste heat were controlled using two programmable power supply machines. A rapid-prototyping controller with two temperature inputs and three outputs was designed. Rule-based control strategies were coded to maintain optimal temperatures for the emulated proton exchange membrane fuel cells and lithium batteries. To evaluate the heat power of dual energy sources, driving cycles, energy management control, and efficiency maps of energy sources were considered for deriving time-variant values. The main results are as follows: (a an advanced mechatronics platform was constructed; (b a driving cycle simulation was successfully conducted; and (c coolant temperatures reached their optimal operating ranges when the proportional valve, radiator, and coolant pump were sequentially controlled. The benefits of this novel electric-vehicle-based thermal management system are (a high-efficiency operation of energy sources, (b low occupied volume integrated with energy sources, and (c higher electric vehicle traveling mileage. This system will be integrated with real energy sources and a real electric vehicle in the future.

  13. Thermal Management and Reliability of Automotive Power Electronics and Electric Machines

    Energy Technology Data Exchange (ETDEWEB)

    Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cousineau, Justine E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DeVoto, Douglas J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Feng, Xuhui [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kekelia, Bidzina [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kozak, Joseph P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Major, Joshua [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Paret, Paul P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tomerlin, Jeff J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-09

    Low-cost, high-performance thermal management technologies are helping meet aggressive power density, specific power, cost, and reliability targets for power electronics and electric machines. The National Renewable Energy Laboratory is working closely with numerous industry and research partners to help influence development of components that meet aggressive performance and cost targets through development and characterization of cooling technologies, and thermal characterization and improvements of passive stack materials and interfaces. Thermomechanical reliability and lifetime estimation models are important enablers for industry in cost-and time-effective design.

  14. Electrical and thermal characteristics of Bi2212/Ag HTS coils for conduction-cooled SMES

    International Nuclear Information System (INIS)

    Hayakawa, N; Noguchi, S; Kurupakorn, C; Kojima, H; Endo, F; Hirano, N; Nagaya, S; Okubo, H

    2006-01-01

    In this paper, we investigated the electrical and thermal performance of conduction-cooled Bi2212/Ag HTS coils with 4K-GM cryocooler system. First, we measured the critical current I c for different ambient temperatures T 0 at 4.2 K - 40 K. Experimental results revealed that I c increased with the decrease in T 0 and was saturated at T 0 0 = 4.8 K. Experimental results revealed the criterion of thermal runaway, which was discussed in terms of heat generation and propagation in the test coil

  15. Assessment of the once-through cooling alternative for central steam-electric generating stations

    Energy Technology Data Exchange (ETDEWEB)

    Paddock, R. A.; Ditmars, J. D.

    1978-12-01

    The efficacy of the disposal of waste heat from steam-electric power generation by means of once-through cooling systems was examined in the context of the physical aspects of water quality standards and guidelines for thermal discharges. Typical thermal standards for each of the four classes of water bodies (rivers, lakes, estuaries, and coastal waters) were identified. The mixing and dilution characteristics of various discharge modes ranging from simple, shoreline surface discharges to long, submerged multiport diffusers were examined in terms of the results of prototype measurements, analytical model predictions, and physical model studies. General guidelines were produced that indicate, for a given plant capacity, a given type of receiving water body, and a given discharge mode, the likelihood that once-through cooling can be effected within the restrictions of typical thermal standards. In general, it was found that shoreline surface discharges would not be adequate for large power plants (greater than or equal to 500 MW) at estuarine and marine coastal sites, would be marginally adequate at lake sites, and would be acceptable only at river sites with large currents and river discharges. Submerged multiport diffusers were found to provide the greatest likelihood of meeting thermal standards in all receiving water environments.

  16. Assessment of the once-through cooling alternative for central steam-electric generating stations

    International Nuclear Information System (INIS)

    Paddock, R.A.; Ditmars, J.D.

    1978-12-01

    The efficacy of the disposal of waste heat from steam-electric power generation by means of once-through cooling systems was examined in the context of the physical aspects of water quality standards and guidelines for thermal discharges. Typical thermal standards for each of the four classes of water bodies (rivers, lakes, estuaries, and coastal waters) were identified. The mixing and dilution characteristics of various discharge modes ranging from simple, shoreline surface discharges to long, submerged multiport diffusers were examined in terms of the results of prototype measurements, analytical model predictions, and physical model studies. General guidelines were produced that indicate, for a given plant capacity, a given type of receiving water body, and a given discharge mode, the likelihood that once-through cooling can be effected within the restrictions of typical thermal standards. In general, it was found that shoreline surface discharges would not be adequate for large power plants (greater than or equal to 500 MW) at estuarine and marine coastal sites, would be marginally adequate at lake sites, and would be acceptable only at river sites with large currents and river discharges. Submerged multiport diffusers were found to provide the greatest likelihood of meeting thermal standards in all receiving water environments

  17. Simulation of an offshore wind farm using fluid power for centralized electricity generation

    International Nuclear Information System (INIS)

    Jarquin-Laguna, A

    2016-01-01

    A centralized approach for electricity generation within a wind farm is explored through the use of fluid power technology. This concept considers a new way of generation, collection and transmission of wind energy inside a wind farm, in which electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A numerical model was developed to capture the relevant physics from the dynamic interaction between different turbines coupled to a common hydraulic network and controller. This paper presents two examples of the time-domain simulation results for an hypothetical hydraulic wind farm subject to turbulent wind conditions. The performance and operational parameters of individual turbines are compared with those of a reference wind farm with conventional technology turbines, using the same wind farm layout and environmental conditions. For the presented case study, results indicate that the individual wind turbines are able to operate within operational limits with the current pressure control concept. Despite the stochastic turbulent wind input and wake effects, the hydraulic wind farm is able to produce electricity with reasonable performance in both below and above rated conditions. (paper)

  18. Simulation of an offshore wind farm using fluid power for centralized electricity generation

    Directory of Open Access Journals (Sweden)

    A. Jarquin Laguna

    2017-07-01

    Full Text Available A centralized approach for electricity generation within a wind farm is explored through the use of fluid power technology. This concept considers a new way of generation, collection and transmission of wind energy inside a wind farm, in which electrical conversion does not occur during any intermediate conversion step before the energy has reached the offshore central platform. A numerical model was developed to capture the relevant physics from the dynamic interaction between different turbines coupled to a common hydraulic network and controller. This paper presents a few examples of the time domain simulation results for a hypothetical hydraulic wind farm subject to turbulent wind conditions. The performance and operational parameters of individual turbines are compared with those of a reference wind farm based on conventional wind turbine generator technology using the same wind farm layout and environmental conditions. For the presented case studies, results indicate that the individual wind turbines are able to operate within operational limits. Despite the stochastic turbulent wind conditions and wake effects, the hydraulic wind farm is able to produce electricity with reasonable performance in both below and above rated conditions. With the current pressure control concept, a continuous operation of the hydraulic wind farm is shown including the full stop of one or more turbines.

  19. Thermal performance of heavy-weight and light-weight steel frame construction approaches in the central Pretoria climate

    CSIR Research Space (South Africa)

    Kumirai, T

    2013-01-01

    Full Text Available -1 Journal for New Generation Sciences Thermal performance of heavy-weight and light-weight steel frame construction approaches in the central Pretoria climate T Kumirai and DCU Conradie Built Environment, Council for Scientific and Industrial...

  20. A Thermally-Regenerative Ammonia-Based Flow Battery for Electrical Energy Recovery from Waste Heat.

    Science.gov (United States)

    Zhu, Xiuping; Rahimi, Mohammad; Gorski, Christopher A; Logan, Bruce

    2016-04-21

    Large amounts of low-grade waste heat (temperatures energy can be converted to electricity in battery systems. To improve reactor efficiency, a compact, ammonia-based flow battery (AFB) was developed and tested at different solution concentrations, flow rates, cell pairs, and circuit connections. The AFB achieved a maximum power density of 45 W m(-2) (15 kW m(-3) ) and an energy density of 1260 Wh manolyte (-3) , with a thermal energy efficiency of 0.7 % (5 % relative to the Carnot efficiency). The power and energy densities of the AFB were greater than those previously reported for thermoelectrochemical and salinity-gradient technologies, and the voltage or current could be increased using stacked cells. These results demonstrated that an ammonia-based flow battery is a promising technology to convert low-grade thermal energy to electricity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Electricity

    International Nuclear Information System (INIS)

    Tombs, F.

    1983-01-01

    The subject is discussed, with particular reference to the electricity industry in the United Kingdom, under the headings; importance and scope of the industry's work; future fuel supplies (estimated indigenous fossil fuels reserves); outlook for UK energy supplies; problems of future generating capacity and fuel mix (energy policy; construction programme; economics and pricing; contribution of nuclear power - thermal and fast reactors; problems of conversion of oil-burning to coal-burning plant). (U.K.)

  2. Ground-state splitting of ultrashallow thermal donors with negative central-cell corrections in silicon

    Science.gov (United States)

    Hara, Akito; Awano, Teruyoshi

    2017-06-01

    Ultrashallow thermal donors (USTDs), which consist of light element impurities such as carbon, hydrogen, and oxygen, have been found in Czochralski silicon (CZ Si) crystals. To the best of our knowledge, these are the shallowest hydrogen-like donors with negative central-cell corrections in Si. We observed the ground-state splitting of USTDs by far-infrared optical absorption at different temperatures. The upper ground-state levels are approximately 4 meV higher than the ground-state levels. This energy level splitting is also consistent with that obtained by thermal excitation from the ground state to the upper ground state. This is direct evidence that the wave function of the USTD ground state is made up of a linear combination of conduction band minimums.

  3. Low-temperature thermal reduction of graphene oxide: In situ correlative structural, thermal desorption, and electrical transport measurements

    Science.gov (United States)

    Lipatov, Alexey; Guinel, Maxime J.-F.; Muratov, Dmitry S.; Vanyushin, Vladislav O.; Wilson, Peter M.; Kolmakov, Andrei; Sinitskii, Alexander

    2018-01-01

    Elucidation of the structural transformations in graphene oxide (GO) upon reduction remains an active and important area of research. We report the results of in situ heating experiments, during which electrical, mass spectrometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) measurements were carried out correlatively. The simultaneous electrical and temperature programmed desorption measurements allowed us to correlate the onset of the increase in the electrical conductivity of GO by five orders of magnitude at about 150 °C with the maxima of the rates of desorption of H2O, CO, and CO2. Interestingly, this large conductivity change happens at an intermediate level of the reduction of GO, which likely corresponds to the point when the graphitic domains become large enough to enable percolative electronic transport. We demonstrate that the gas desorption is intimately related to (i) the changes in the chemical structure of GO detected by XPS and Raman spectroscopy and (ii) the formation of nanoscopic holes in GO sheets revealed by TEM. These in situ observations provide a better understanding of the mechanism of the GO thermal reduction.

  4. Effect of thermal treatment on electrical properties and varistors degradation of ZnO

    International Nuclear Information System (INIS)

    Leite, E.R.; Cerri, J.A.; Longo, E.; Catao, P.S.P.; Varela, J.A.

    1990-01-01

    ZnO varistors obstained by conventional processing was heat treated and their electrical properties and degradation was analyzed. Infra-red spectroscopy, X-Ray diffraction and current-voltage curves were used to analize the properties with type of thermal cycle. The results showed that heat treatment promote stabilization against degradation and that exist a linear dependence of leakage current with square root of time. (author) [pt

  5. Fabrication, thermal and electrical properties of polyphenylene sulphide/copper composites

    International Nuclear Information System (INIS)

    Goyal, R.K.; Kambale, K.R.; Nene, S.S.; Selukar, B.S.; Arbuj, S.; Mulik, U.P.

    2011-01-01

    Highlights: → Polyphenylene sulphide/copper composites show a low percolation threshold, i.e., about 6 vol% Cu. → Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. → The microhardness was increased by more than 50% compared to pure PPS matrix. → The electrical conductivity was increased by about eight orders of magnitude for 18 vol% Cu composite. → Dielectric constant and dissipation factor of composites measured at MHz was increased to about 6-fold and 70-fold compared to PPS matrix. - Abstract: The thermal and electrical properties of high performance poly(phenylene sulphide) (PPS) composites reinforced up to 31 vol% Cu particles were investigated to be used as materials for electronic applications. The thermal stability and char yield of the composites increased significantly. Both pre- and post- glass transition coefficient of thermal expansion (CTE) of composites decreased significantly. The microhardness was increased by more than 50% compared to pure PPS matrix. Microhardness and CTE of composites correlated well with the rule of mixtures. A percolation threshold about 6 vol% Cu was obtained. The electrical conductivity was increased by about eight orders of magnitude for 18 vol% composite. Dielectric constant and dissipation factor of composites at 1 MHz was increased by about 6-fold and 70-fold compared to matrix, respectively. They decreased gradually with increasing frequency up to 1 MHz and thereafter, there was insignificant change. The scanning electron microscope showed almost uniform distribution of Cu particles in the matrix. Owing to better dimensional stability and good electrical properties, these composites are very promising for electronic applications.

  6. Research on electric and thermal characteristics of plasma torch based on similarity theory

    International Nuclear Information System (INIS)

    Cheng Changming; Tang Deli; Lan Wei

    2007-01-01

    Configuration and working principle of a DC non-transferred plasma torch have been introduced. Based on similarity theory, connections between the electric-thermal characteristics and operational parameter such as flowing gas rate and arc power have been investigated. Calculation and experiment are compared. The results indicate that the calculation results are in agreement with experimental ones. The formulas can be used for plasma torch improvement and optimization. (authors)

  7. Fast Lagrangian relaxation for constrained generation scheduling in a centralized electricity market

    International Nuclear Information System (INIS)

    Ongsakul, Weerakorn; Petcharaks, Nit

    2008-01-01

    This paper proposes a fast Lagrangian relaxation (FLR) for constrained generation scheduling (CGS) problem in a centralized electricity market. FLR minimizes the consumer payment rather than the total supply cost subject to the power balance, spinning reserve, transmission line, and generator operating constraints. FLR algorithm is improved by new initialization of Lagrangian multipliers and adaptive adjustment of Lagrangian multipliers. The adaptive subgradient method using high quality initial feasible multipliers requires much less number of iterations to converge, leading to a faster computational time. If congestion exists, the alleviating congestion index is proposed for congestion management. Finally, the unit decommitment is performed to prevent excessive spinning reserve. The FLR for CGS is tested on the 4 unit and the IEEE 24 bus reliability test systems. The proposed uniform electricity price results in a lower consumer payment than system marginal price based on uniformly fixed cost amortized allocation, non-uniform price, and electricity price incorporating side payment, leading to a lower electricity price. In addition, observations on objective functions, pricing scheme comparison and interpretation of Lagrangian multipliers are provided. (author)

  8. Thermal analysis of the unloading cell of the Spanish centralized interim storage facility (CISF)

    International Nuclear Information System (INIS)

    Perez Dominguez, J. R.; Perez Vara, R.; Huelamo Martinez, E.

    2016-01-01

    This article deals with the thermal analysis performed for the Untoading Cell of Spain Centralized Interim Storage Facility, CISF (ATC, in Spanish). The analyses are done using computational fluid dynamics (CFD) simulation, with the aim of obtaining the air flow required to remove the residual heat of the elements stored in the cell. Compliance with the admissible heat limits is checked with the results obtained in the various operation and accident modes. The calculation model is flexible enough to allow carrying out a number of sensitivity analyses with the different parameters involved in the process. (Author)

  9. Localization of thermal anomalies in electrical equipment using Infrared Thermography and support vector machine

    Science.gov (United States)

    Laib dit Leksir, Y.; Mansour, M.; Moussaoui, A.

    2018-03-01

    Analysis and processing of databases obtained from infrared thermal inspections made on electrical installations require the development of new tools to obtain more information to visual inspections. Consequently, methods based on the capture of thermal images show a great potential and are increasingly employed in this field. However, there is a need for the development of effective techniques to analyse these databases in order to extract significant information relating to the state of the infrastructures. This paper presents a technique explaining how this approach can be implemented and proposes a system that can help to detect faults in thermal images of electrical installations. The proposed method classifies and identifies the region of interest (ROI). The identification is conducted using support vector machine (SVM) algorithm. The aim here is to capture the faults that exist in electrical equipments during an inspection of some machines using A40 FLIR camera. After that, binarization techniques are employed to select the region of interest. Later the comparative analysis of the obtained misclassification errors using the proposed method with Fuzzy c means and Ostu, has also be addressed.

  10. Adaptive algorithm for predicting increases in central loads of electrical energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Arbachyauskene, N A; Pushinaytis, K V

    1982-01-01

    An adaptive algorithm for predicting increases in central loads of the electrical energy system is suggested for the task of evaluating the condition. The algorithm is based on the Kalman filter. In order to calculate the coefficient of intensification, the a priori assigned noise characteristics with low accuracy are used only in the beginning of the calculation. Further, the coefficient of intensification is calculated from the innovation sequence. This approach makes it possible to correct errors in the assignment of the statistical noise characteristics and to follow their changes. The algorithm is experimentally verified.

  11. Intake-to-delivered-energy ratios for central station and distributed electricity generation in California

    International Nuclear Information System (INIS)

    Heath, Garvin A.; Nazaroff, William W.

    2007-01-01

    In previous work, we showed that the intake fraction (iF) for nonreactive primary air pollutants was 20 times higher in central tendency for small-scale, urban-sited distributed electricity generation (DG) sources than for large-scale, central station (CS) power plants in California [Heath, G.A., Granvold, P.W., Hoats, A.S., Nazaroff, W.W., 2006. Intake fraction assessment of the air pollutant exposure implications of a shift toward distributed electricity generation. Atmospheric Environment 40, 7164-7177]. The present paper builds on that study, exploring pollutant- and technology-specific aspects of population inhalation exposure from electricity generation. We compare California's existing CS-based system to one that is more reliant on DG units sited in urban areas. We use Gaussian plume modeling and a GIS-based exposure analysis to assess 25 existing CSs and 11 DG sources hypothetically located in the downtowns of California's most populous cities. We consider population intake of three pollutants - PM 2.5 , NO x and formaldehyde - directly emitted by five DG technologies - natural gas (NG)-fired turbines, NG internal combustion engines (ICE), NG microturbines, diesel ICEs, and fuel cells with on-site NG reformers. We also consider intake of these pollutants from existing CS facilities, most of which use large NG turbines, as well as from hypothetical facilities located at these same sites but meeting California's best-available control technology standards. After systematically exploring the sensitivity of iF to pollutant decay rate, the iFs for each of the three pollutants for all DG and CS cases are estimated. To efficiently compare the pollutant- and technology-specific exposure potential on an appropriate common basis, a new metric is introduced and evaluated: the intake-to-delivered-energy ratio (IDER). The IDER expresses the mass of pollutant inhaled by an exposed population owing to emissions from an electricity generation unit per quantity of electric

  12. Intake-to-delivered-energy ratios for central station and distributed electricity generation in California

    Science.gov (United States)

    Heath, Garvin A.; Nazaroff, William W.

    In previous work, we showed that the intake fraction (iF) for nonreactive primary air pollutants was 20 times higher in central tendency for small-scale, urban-sited distributed electricity generation (DG) sources than for large-scale, central station (CS) power plants in California [Heath, G.A., Granvold, P.W., Hoats, A.S., Nazaroff, W.W., 2006. Intake fraction assessment of the air pollutant exposure implications of a shift toward distributed electricity generation. Atmospheric Environment 40, 7164-7177]. The present paper builds on that study, exploring pollutant- and technology-specific aspects of population inhalation exposure from electricity generation. We compare California's existing CS-based system to one that is more reliant on DG units sited in urban areas. We use Gaussian plume modeling and a GIS-based exposure analysis to assess 25 existing CSs and 11 DG sources hypothetically located in the downtowns of California's most populous cities. We consider population intake of three pollutants—PM 2.5, NO x and formaldehyde—directly emitted by five DG technologies—natural gas (NG)-fired turbines, NG internal combustion engines (ICE), NG microturbines, diesel ICEs, and fuel cells with on-site NG reformers. We also consider intake of these pollutants from existing CS facilities, most of which use large NG turbines, as well as from hypothetical facilities located at these same sites but meeting California's best-available control technology standards. After systematically exploring the sensitivity of iF to pollutant decay rate, the iFs for each of the three pollutants for all DG and CS cases are estimated. To efficiently compare the pollutant- and technology-specific exposure potential on an appropriate common basis, a new metric is introduced and evaluated: the intake-to-delivered-energy ratio (IDER). The IDER expresses the mass of pollutant inhaled by an exposed population owing to emissions from an electricity generation unit per quantity of electric

  13. Optimization analysis of thermal management system for electric vehicle battery pack

    Science.gov (United States)

    Gong, Huiqi; Zheng, Minxin; Jin, Peng; Feng, Dong

    2018-04-01

    Electric vehicle battery pack can increase the temperature to affect the power battery system cycle life, charge-ability, power, energy, security and reliability. The Computational Fluid Dynamics simulation and experiment of the charging and discharging process of the battery pack were carried out for the thermal management system of the battery pack under the continuous charging of the battery. The simulation result and the experimental data were used to verify the rationality of the Computational Fluid Dynamics calculation model. In view of the large temperature difference of the battery module in high temperature environment, three optimization methods of the existing thermal management system of the battery pack were put forward: adjusting the installation position of the fan, optimizing the arrangement of the battery pack and reducing the fan opening temperature threshold. The feasibility of the optimization method is proved by simulation and experiment of the thermal management system of the optimized battery pack.

  14. Thermal, Electrical and Mechanical Response to a Quench in Nb3Sn Superconducting Coils

    International Nuclear Information System (INIS)

    Ferracin, F.; Caspi, S.; Chiesa, L.; Gourlay, S.A.; Hafalia, R.R.; Imbasciati, L.; Lietzke, A.F.; Sabbi, G.; Scanlan, R.M.

    2003-01-01

    During a quench, significant temperatures can arise as a magnet's stored energy is dissipated in the normal zone. Temperature gradients during this process give rise to localized strains within the coil. Reactive forces in the magnet structure balance the electromagnetic and thermal forces and maintain on equilibrium. In this paper we present a complete 3D finite element analysis of a racetrack coil. Specifically, the analysis focuses on thermal, electrical and mechanical conditions in a 10 T Nb 3 Sn coil built and tested as part of LBNL's Subscale Magnet Program. The study attempts to simulate time history of the temperature and voltage rise during quench propagation. The transient thermal stress after the quench is then evaluated and discussed

  15. Thermo-optically tuned photonic resonators with concurrent electrical connection and thermal isolation

    Science.gov (United States)

    Lentine, Anthony L.; Kekatpure, Rohan Deodatta; Zortman, William A.; Savignon, Daniel J.

    2016-06-14

    A photonic resonator system is designed to use thermal tuning to adjust the resonant wavelength of each resonator in the system, with a separate tuning circuit associated with each resonator so that individual adjustments may be made. The common electrical ground connection between the tuning circuits is particularly formed to provide thermal isolation between adjacent resonators by including a capacitor along each return path to ground, where the presence of the capacitor's dielectric material provides the thermal isolation. The use of capacitively coupling necessarily requires the use of an AC current as an input to the heater element (conductor/resistor) of each resonator, where the RMS value of the AC signal is indicative of the amount of heat that is generated along the element and the degree of wavelength tuning that is obtained.

  16. Modeling of thermal spalling during electrical discharge machining of titanium diboride

    International Nuclear Information System (INIS)

    Gadalla, A.M.; Bozkurt, B.; Faulk, N.M.

    1991-01-01

    Erosion in electrical discharge machining has been described as occurring by melting and flushing the liquid formed. Recently, however, thermal spalling was reported as the mechanism for machining refractory materials with low thermal conductivity and high thermal expansion. The process is described in this paper by a model based on a ceramic surface exposed to a constant circular heating source which supplied a constant flux over the pulse duration. The calculations were based on TiB 2 mechanical properties along a and c directions. Theoretical predictions were verified by machining hexagonal TiB 2 . Large flakes of TiB 2 with sizes close to grain size and maximum thickness close to the predicted values were collected, together with spherical particles of Cu and Zn eroded from cutting wire. The cutting surfaces consist of cleavage planes sometimes contaminated with Cu, Zn, and impurities from the dielectric fluid

  17. Electrical and thermal characteristics of Bi2212/Ag HTS coils for conduction-cooled SMES

    Science.gov (United States)

    Hayakawa, N.; Noguchi, S.; Kurupakorn, C.; Kojima, H.; Endo, F.; Hirano, N.; Nagaya, S.; Okubo, H.

    2006-06-01

    In this paper, we investigated the electrical and thermal performance of conduction-cooled Bi2212/Ag HTS coils with 4K-GM cryocooler system. First, we measured the critical current Ic for different ambient temperatures T0 at 4.2 K - 40 K. Experimental results revealed that Ic increased with the decrease in T0 and was saturated at T0 account of temperature dependence of specific heat and thermal conductivity of the materials. We also measured the temperature rise of Bi2212/Ag HTS coil for different continuous current levels at T0 = 4.8 K. Experimental results revealed the criterion of thermal runaway, which was discussed in terms of heat generation and propagation in the test coil.

  18. Heat transfer due to electroconvulsive therapy: Influence of anisotropic thermal and electrical skull conductivity.

    Science.gov (United States)

    Menezes de Oliveira, Marilia; Wen, Peng; Ahfock, Tony

    2016-09-01

    This paper focuses on electroconvulsive therapy (ECT) and head models to investigate temperature profiles arising when anisotropic thermal and electrical conductivities are considered in the skull layer. The aim was to numerically investigate the threshold for which this therapy operates safely to the brain, from the thermal point of view. A six-layer spherical head model consisting of scalp, fat, skull, cerebro-spinal fluid, grey matter and white matter was developed. Later on, a realistic human head model was also implemented. These models were built up using the packages from COMSOL Inc. and Simpleware Ltd. In these models, three of the most common electrode montages used in ECT were applied. Anisotropic conductivities were derived using volume constraint and included in both spherical and realistic head models. The bio-heat transferring problem governed by Laplace equation was solved numerically. The results show that both the tensor eigenvalues of electrical conductivity and the electrode montage affect the maximum temperature, but thermal anisotropy does not have a significant influence. Temperature increases occur mainly in the scalp and fat, and no harm is caused to the brain by the current applied during ECT. The work assures the thermal safety of ECT and also provides a numerical method to investigate other non-invasive therapies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Electrical resistivity and thermal properties of compatibilized multi-walled carbon nanotube/polypropylene composites

    Directory of Open Access Journals (Sweden)

    A. Szentes

    2012-06-01

    Full Text Available The electrical resistivity and thermal properties of multi-walled carbon nanotube/polypropylene (MWCNT/PP composites have been investigated in the presence of coupling agents applied for improving the compatibility between the nanotubes and the polymer. A novel olefin-maleic-anhydride copolymer and an olefin-maleic-anhydride copolymer based derivative have been used as compatibilizers to achieve better dispersion of MWCNTs in the polymer matrix. The composites have been produced by extrusion followed by injection moulding. They contained different amounts of MWCNTs (0.5, 2, 3 and 5 wt% and coupling agent to enhance the interactions between the carbon nanotubes and the polymer. The electrical resistivity of the composites has been investigated by impedance spectroscopy, whereas their thermal properties have been determined using a thermal analyzer operating on the basis of the periodic thermal perturbation method. Rheological properties, BET-area and adsorption-desorption isotherms have been determined. Dispersion of MWCNTs in the polymer has been studied by scanning electron microscopy (SEM.

  20. Environmental Synthesis of Few Layers Graphene Sheets Using Ultrasonic Exfoliation with Enhanced Electrical and Thermal Properties.

    Directory of Open Access Journals (Sweden)

    Monir Noroozi

    Full Text Available In this paper, we report how few layers graphene that can be produced in large quantity with low defect ratio from exfoliation of graphite by using a high intensity probe sonication in water containing liquid hand soap and PVP. It was founded that the graphene powder obtained by this simple exfoliation method after the heat treatment had an excellent exfoliation into a single or layered graphene sheets. The UV-visible spectroscopy, FESEM, TEM, X-ray powder diffraction and Raman spectroscopy was used to analyse the graphene product. The thermal diffusivity of the samples was analysed using a highly accurate thermal-wave cavity photothermal technique. The data obtained showed excellent enhancement in the thermal diffusivity of the graphene dispersion. This well-dispersed graphene was then used to fabricate an electrically conductive polymer-graphene film composite. The results demonstrated that this low cost and environmental friendly technique allowed to the production of high quality layered graphene sheets, improved the thermal and electrical properties. This may find use in the wide range of applications based on graphene.

  1. Thermal strain measurement of EAST W/Cu divertor structure using electric resistance strain gauges

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xingli [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Wang, Wanjing, E-mail: wjwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Wang, Jichao [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Wei, Ran; Sun, Zhaoxuan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Li, Qiang; Xie, Chunyi [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Chen, Hong-En; Wang, Kaiqiang; Wu, Lei; Chen, Zhenmao [State Key Lab for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University (China); Luo, Guang-Nan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Hefei Center for Physical Science and Technology, Hefei, 230022 (China); Hefei Science Center of Chinese Academy of Sciences, Hefei, 230027 (China)

    2016-12-15

    Highlights: • To understand the service behavior of W/Cu divertor, an electrical resistance strain gauge system had been introduced in a thermal strain measurement experiment. • The measurement system successfully finished the experiment and obtained valued thermal strain data. • Two thermomechanical analyses had also been carried out and compared with the measurement results. • Experiment results corresponded well to simulations and threw a light upon the failure of W/Cu divertor in the previous baking tests. - Abstract: W/Cu divertor has complex structure and faces extreme work environment in EAST Tokamak device. To measure its thermal strain shall be a valued way to understand its service behavior and then optimize its design and manufacturing process. This work presents a preliminary study on measuring thermal strain of EAST W/Cu divertor structure using electric resistance strain gauges. Eight gauges had been used in the experiment and the heating temperature had been set to 230 °C with respect to the work temperature. To realize the measuring experiment, an appropriate fixing method of gauges in divertor narrow spaces had been taken and tested, which could not only withstand high temperature but also had no damage to the divertor sample. The measurement results were that three gauges showed positive strain while other three showed negative strain after having been compensated, which corresponded to tensile stress and compressed stress respectively. Two thermomechanical simulations had also been carried out and used for comparing with the experiment.

  2. Integrated Electrical and Thermal Grid Facility - Testing of Future Microgrid Technologies

    Directory of Open Access Journals (Sweden)

    Sundar Raj Thangavelu

    2015-09-01

    Full Text Available This paper describes the Experimental Power Grid Centre (EPGC microgrid test facility, which was developed to enable research, development and testing for a wide range of distributed generation and microgrid technologies. The EPGC microgrid facility comprises a integrated electrical and thermal grid with a flexible and configurable architecture, and includes various distributed energy resources and emulators, such as generators, renewable, energy storage technologies and programmable load banks. The integrated thermal grid provides an opportunity to harness waste heat produced by the generators for combined heat, power and cooling applications, and support research in optimization of combined electrical-thermal systems. Several case studies are presented to demonstrate the testing of different control and operation strategies for storage systems in grid-connected and islanded microgrids. One of the case studies also demonstrates an integrated thermal grid to convert waste heat to useful energy, which thus far resulted in a higher combined energy efficiency. Experiment results confirm that the facility enables testing and evaluation of grid technologies and practical problems that may not be apparent in a computer simulated environment.

  3. Predictive values of thermal and electrical dental pulp tests: a clinical study.

    Science.gov (United States)

    Villa-Chávez, Carlos E; Patiño-Marín, Nuria; Loyola-Rodríguez, Juan P; Zavala-Alonso, Norma V; Martínez-Castañón, Gabriel A; Medina-Solís, Carlo E

    2013-08-01

    For a diagnostic test to be useful, it is necessary to determine the probability that the test will provide the correct diagnosis. Therefore, it is necessary to calculate the predictive value of diagnostics. The aim of the present study was to identify the sensitivity, specificity, positive and negative predictive values, accuracy, and reproducibility of thermal and electrical tests of pulp sensitivity. The thermal tests studied were the 1, 1, 1, 2-tetrafluoroethane (cold) and hot gutta-percha (hot) tests. For the electrical test, the Analytic Technology Pulp Tester (Analytic Technology, Redmond, WA) was used. A total of 110 teeth were tested: 60 teeth with vital pulp and 50 teeth with necrotic pulps (disease prevalence of 45%). The ideal standard was established by direct pulp inspection. The sensitivities of the diagnostic tests were 0.88 for the cold test, 0.86 for the heat test, and 0.76 for the electrical test, and the specificity was 1.0 for all 3 tests. The negative predictive value was 0.90 for the cold test, 0.89 for the heat test, and 0.83 for the electrical test, and the positive predictive value was 1.0 for all 3 tests. The highest accuracy (0.94) and reproducibility (0.88) were observed for the cold test. The cold test was the most accurate method for diagnostic testing. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Thermal and Electrical Characterization of the Carbon Nanofibers Based Cement Composites

    Directory of Open Access Journals (Sweden)

    Agnieszka ŚLOSARCZYK

    2017-08-01

    Full Text Available The paper describes the influence of chemical modification of vapor grown carbon nanofibers (VGCnFs on the thermal and electrical properties of the cement composites. The surface modification of nanofibers was performed by means of ozone and nitric acid treatments. It was shown that the oxidized carbon nanofibers surface plays an important role in shaping the mechanical and especially electrical properties of cement composite. For cement matrix modified with carbon nanofibers subjected to oxidized treatment, the slightly increase of cement paste resistivity was observed. It confirms the better adhesion of carbon nanofibers to cement paste. However, independently of carbon nanofibers modification, the occurrence of VGCnFs in cement paste increased the electrical conductivity of the composite in comparison to the cement paste without fibers. The obtained values of electrical resistivity were comparable with values of cement composites modified with 4 mm long carbon fibers. Moreover, it was shown that the chemical modification of carbon nanofibers surface does not influence on the thermal properties of cement composites. In case of cement paste with unmodified and modified carbon nanofibers, the Seebeck voltage was proportional to the temperature difference and was independent of the oxidation degree of carbon nanofibers.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.14993

  5. Date palm biochar-polymer composites: An investigation of electrical, mechanical, thermal and rheological characteristics.

    Science.gov (United States)

    Poulose, Anesh Manjaly; Elnour, Ahmed Yagoub; Anis, Arfat; Shaikh, Hamid; Al-Zahrani, S M; George, Justin; Al-Wabel, Mohammad I; Usman, Adel R; Ok, Yong Sik; Tsang, Daniel C W; Sarmah, Ajit K

    2018-04-01

    The application of biochar (BC) as a filler in polymers can be viewed as a sustainable approach that incorporates pyrolysed waste based value-added material and simultaneously mitigate bio-waste in a smart way. The overarching aim of this work was to investigate the electrical, mechanical, thermal and rheological properties of biocomposite developed by utilizing date palm waste-derived BC for the reinforcing of polypropylene (PP) matrix. Date palm waste derived BC prepared at (700 and 900°C) were blended at different proportions with polypropylene and the resultant composites (BC/PP) were characterized using an array of techniques (scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier transform infra-red spectroscopy). Additionally the thermal, mechanical, electrical and rheological properties of the BC/PP composites were evaluated at different loading of BC content (from 0 to15% w/w). The mechanical properties of BC/PP composites showed an improvement in the tensile modulus while that of electrical characterization revealed an enhanced electrical conductivity with increased BC loading. Although the BC incorporation into the PP matrix has significantly reduced the total crystallinity of the resulted composites, however; a positive effect on the crystallization temperature (T c ) was observed. The rheological characterization of BC/PP composites revealed that the addition of BC had minimal effect on the storage modulus (G') compared to the neat (PP). Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Joining and Performance of Alkali Metal Thermal-to-electric Converter (AMTEC)

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Min-Soo; Lee, Wook-Hyun; Woo, Sang-Kuk [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2017-07-15

    The alkali-Metal Thermal-to-electric Converter (AMTEC) is one of the promising static energy conversion technologies for the direct conversion of thermal energy to electrical energy. The advantages over a conventional energy converter are its high theoretical conversion efficiency of 40% and power density of 500 W/kg. The working principle of an AMTEC battery is the electrochemical reaction of the sodium through an ion conducting electrolyte. Sodium ion pass through the hot side of the beta”-alumina solid electrolyte (BASE) primarily as a result of the pressure difference. This pressure difference across the BASE has a significant effect on the overall performance of the AMTEC system. In order to build the high pressure difference across the BASE, hermeticity is required for each joined components for high temperature range of 900°C. The AMTEC battery was manufactured by utilizing robust joining technology of BASE/insulator/metal flange interfaces of the system for both structural and electrical stability. The electrical potential difference between the anode and cathode sides, where the electrons emitted from sodium ionization and recombined into sodium, was characterized as the open-circuit voltage. The efforts of technological improvement were concentrated on a high-power output and conversion efficiency. This paper discusses about the joining and performance of the AMTEC systems.

  7. Exergy analysis of thermal management system for range-extended electric vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Hamut, H. S.; Dincer, I.; Naterer, G. F. [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology (Canada)], email: Ibrahim.Dincer@uoit.ca

    2011-07-01

    In the last few decades, the energy crisis, increasing gas prices and concerns over environmental pollution have encouraged the development of electric vehicle (EV) and hybrid electric vehicle (HEV) technologies. In this paper, a thermal management system (TMS) installed in a range-extended electric vehicle is examined and is found to have a substantial impact on battery efficiency and vehicle performance. An exergy analysis was conducted on the refrigeration and coolant circuits and the Coefficient of Performance (COP) of the baseline system was determined to be 2.0 with a range of 1.8 to 2.4. The overall exergy was found to be 32% with a range of 26% to 39%. Ambient temperature had the largest impact on overall exergy efficiency but there is a need to further investigate temperature effects on battery efficiency, since the battery's performance has such a high impact on vehicle performance overall.

  8. Local electrical properties of thermally grown oxide films formed on duplex stainless steel surfaces

    Science.gov (United States)

    Guo, L. Q.; Yang, B. J.; He, J. Y.; Qiao, L. J.

    2018-06-01

    The local electrical properties of thermally grown oxide films formed on ferrite and austenite surfaces of duplex stainless steel at different temperatures were investigated by Current sensing atomic force microscopy, X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). The current maps and XPS/AES analyses show that the oxide films covering austenite and ferrite surfaces formed at different temperatures exhibit different local electrical characteristics, thickness and composition. The dependence of electrical conductivity of oxide films covering austenite and ferrite surface on the formation temperature is attributed to the film thickness and semiconducting structures, which is intrinsically related to thermodynamics and kinetics process of film grown at different temperature. This is well elucidated by corresponding semiconductor band structures of oxide films formed on austenite and ferrite phases at different temperature.

  9. Resources transfer and centralization in Brazilian electrical sector: the reversion global reserve (RGR) and the guarantee global reserve (GGR)

    International Nuclear Information System (INIS)

    Souza Amaral Filho, J.B. de.

    1991-01-01

    This dissertation makes the analysis of resources transfer and centralization in Brazilian electrical sector, through reversion global reserve (RGR) and guarantee global reserve (GGR). RGR and GGR are funds. RGR finances sectorial investments in electric power and GGR aims the supply of deficient concessionaires. Governmental investments and the results of this application are showing. (M.V.M.). 55 refs, 2 figs, 61 tabs

  10. Proposed Use of Zero Bias Diode Arrays as Thermal Electric Noise Rectifiers and Non-Thermal Energy Harvesters

    Science.gov (United States)

    Valone, Thomas F.

    2009-03-01

    The well known built-in voltage potential for some select semiconductor p-n junctions and various rectifying devices is proposed to be favorable for generating DC electricity at "zero bias" (with no DC bias voltage applied) in the presence of Johnson noise or 1/f noise which originates from the quantum vacuum (Koch et al., 1982). The 1982 Koch discovery that certain solid state devices exhibit measurable quantum noise has also recently been labeled a finding of dark energy in the lab (Beck and Mackey, 2004). Tunnel diodes are a class of rectifiers that are qualified and some have been credited with conducting only because of quantum fluctuations. Microwave diodes are also good choices since many are designed for zero bias operation. A completely passive, unamplified zero bias diode converter/detector for millimeter (GHz) waves was developed by HRL Labs in 2006 under a DARPA contract, utilizing a Sb-based "backward tunnel diode" (BTD). It is reported to be a "true zero-bias diode." It was developed for a "field radiometer" to "collect thermally radiated power" (in other words, 'night vision'). The diode array mounting allows a feed from horn antenna, which functions as a passive concentrating amplifier. An important clue is the "noise equivalent power" of 1.1 pW per root hertz and the "noise equivalent temperature difference" of 10° K, which indicate sensitivity to Johnson noise (Lynch, et al., 2006). There also have been other inventions such as "single electron transistors" that also have "the highest signal to noise ratio" near zero bias. Furthermore, "ultrasensitive" devices that convert radio frequencies have been invented that operate at outer space temperatures (3 degrees above zero point: 3° K). These devices are tiny nanotech devices which are suitable for assembly in parallel circuits (such as a 2-D array) to possibly produce zero point energy direct current electricity with significant power density (Brenning et al., 2006). Photovoltaic p-n junction

  11. Feasibility assessment of a solar-powered charging station for electric vehicles in the North Central region of Bulgaria

    Directory of Open Access Journals (Sweden)

    Ilieva Liliya Mihaylova

    2016-01-01

    Full Text Available The paper discusses the topical issue related to the prospects of widespread deployment of electric vehicles and their associated infrastructure in Bulgaria. The main problems hindering the development of electric vehicle transport are summarized and the current status of charging infrastructure in the country is discussed. An approach is proposed for analysis and evaluation of the financial feasibility of investment in a solar-powered charging station for electric vehicles in North Central region of Bulgaria.

  12. Perspectives for long-term competition in the central European electricity market

    International Nuclear Information System (INIS)

    Haas, Reinhard

    2005-01-01

    In this paper we focus on the Central European electricity market and analyse whether liberalization, deregulation, and privatization are sufficient to bring about real competition. Moreover, we discuss the relevance of the following conditions to bring about real competition and to avoid market power: 1) A rigorous correct un bundling; 2) excess capacities in transmission; 3) excess capacities in generation; 4) a large number of generators and suppliers; 5) the balanced existence of short-term (e.g. spot markets) and long-term markets (e.g. bilateral contracts, forwards); 6) full liberalization; Some major findings of this analysis are: 1) Currently, demand is continuously increasing while capacities are shut down. At least in 2009 demand will have caught up with generation capacities. This could lead to severe price spikes. 2) The Central European electricity market is separated from other markets by means of limited transmission capacities; 3) With respect to effective competition in Central Europe the major problems are: i) a very small (and continuously decreasing) number of generators, and ii) a lack of serious un bundling between generation and transmission mainly in Germany; This leads to cross-subsidization of generation by the network operation and to a heavy discrimination of other and new generators; 4) Moreover, a crucial condition for active competition is a sufficiently large transmission grid. Yet, currently especially at the border to the new EU member countries transmission capacities are rather scarce and there are no signs of extensions of the grid. This also limits the access of countries with potential excess capacities like Ukraine, Bulgaria, Romania to the Central European market The major conclusion of this analysis is: All conditions investigated above must be fulfilled simultaneously to bring about a competitive electricity market in Western Europe and the extended European Union. If only one of these conditions is missing, competition

  13. 222Rn determination in some thermal baths of a central eastern Italian area

    International Nuclear Information System (INIS)

    Desideri, D.; Bruno, M.R.; Roselli, C.

    2004-01-01

    Some recent Italian laws, based on the Euratom Directive 26/96, introduce the obligation of monitoring the exposition to natural radioactivity in particular worksites (thermal baths, mines, basements, etc.). Results of 222 Rn measurements in some thermal baths of Rimini and Pesaro-Urbino provinces (Central Eastern Italy), by Radosys-2000, a complete set suitable to radon concentration measurements with CR-39 plastic alpha-track detectors are reported. Some areas where radon could accumulate (bathing, reaction, muddy, inhalation, insufflation rooms and swimming pools) were selected for the investigation. The dosimeters have been exposed for 98 days. The results show that 222 Rn concentrations are very low in the considered thermal baths (7-71 Bq x m -3 ). Moreover, no difference was observed between the concentrations measured in the therapy rooms (bathing, muddy, inhalation and insufflation rooms, swimming pools) and in the normal areas (passages, reaction rooms, dressing rooms, etc.). The calculated dose contribution to workers was about one tenth of the legally suggested value. (author)

  14. Thermal Responses of Growth and Toxin Production in Four Prorocentrum Species from the Central Red Sea

    KAUST Repository

    Aynousah, Arwa

    2017-06-01

    Harmful algae studies, in particular toxic dinoflagellates, and their response to global warming in the Red Sea are still limited. This study was aimed to be the first to characterize the identity, thermal responses and toxin production of four Prorocentrum strains isolated from the Central Red Sea, Saudi Arabia. Morphological and molecular phylogenetic analysis identified the strains as P. elegans, P. rhathymum and P. emarginatum. However, the identity of strain P. sp.6 is currently unresolved, albeit sharing close affinity with P. leve. Growth experiments showed that all species could grow at 24-32°C, but only P. sp.6 survived the 34°C treatment. The optimum temperatures (Topt) estimated from the Gaussian model corresponded to 27.17, 29.33, 26.87, and 27.64°C for P. sp.6, P. elegans, P. rhathymum and P. emarginatum, respectively. However, some discrepancy with the Topt derived from the growth performance were observed for P. elegans and P. emarginatum, as thermal responses differed from the typical Gaussian fit. The Prorocentrum species examined showed a sharp decrease after the optimum temperature resulting in very high activation energies for the fall slope, especially for P. elegans and P. emarginatum. The minimum critical temperature limit for growth was not detected within the range of temperatures examined. Subsequently, high performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis revealed all species as non okadaic acid (OA, common toxin of the Prorocentrum genus) producers at any temperature treatment. However, other forms of toxin (i.e. fast acting toxins) not examined here could be produced. Therefore, further investigations are required. The results of this study provided significant contribution to our knowledge regarding the presence, thermal response and toxin production of four Prorocentrum species from the Central Red Sea, Saudi Arabia.

  15. Bilateral Changes of Spontaneous Activity Within the Central Auditory Pathway Upon Chronic Unilateral Intracochlear Electrical Stimulation.

    Science.gov (United States)

    Basta, Dietmar; Götze, Romy; Gröschel, Moritz; Jansen, Sebastian; Janke, Oliver; Tzschentke, Barbara; Boyle, Patrick; Ernst, Arne

    2015-12-01

    In recent years, cochlear implants have been applied successfully for the treatment of unilateral hearing loss with quite surprising benefit. One reason for this successful treatment, including the relief from tinnitus, could be the normalization of spontaneous activity in the central auditory pathway because of the electrical stimulation. The present study, therefore, investigated at a cellular level, the effect of a unilateral chronic intracochlear stimulation on key structures of the central auditory pathway. Normal-hearing guinea pigs were mechanically single-sided deafened through a standard HiFocus1j electrode array (on a HiRes 90k cochlear implant) being inserted into the first turn of the cochlea. Four to five electrode contacts could be used for the stimulation. Six weeks after surgery, the speech processor (Auria) was fitted, based on tNRI values and mounted on the animal's back. The two experimental groups were stimulated 16 hours per day for 90 days, using a HiRes strategy based on different stimulation rates (low rate (275 pps/ch), high rate (5000 pps/ch)). The results were compared with those of unilateral deafened controls (implanted but not stimulated), as well as between the treatment groups. All animals experienced a standardized free field auditory environment. The low-rate group showed a significantly lower average spontaneous activity bilaterally in the dorsal cochlear nucleus and the medial geniculate body than the controls. However, there was no difference in the inferior colliculus and the primary auditory cortex. Spontaneous activity of the high-rate group was also reduced bilaterally in the dorsal cochlear nucleus and in the primary auditory cortex. No differences could be observed between the high-rate group and the controls in the contra-lateral inferior colliculus and medial geniculate body. The high-rate group showed bilaterally a higher activity in the CN and the MGB compared with the low-rate group, whereas in the IC and in the

  16. Evaluating the use of an urban consolidation centre and electric vehicles in central London

    Directory of Open Access Journals (Sweden)

    Michael Browne

    2011-07-01

    Full Text Available The paper focuses on the role that can be played by urban consolidation centres (UCCs in reducing freight traffic and its environmental impacts in towns and cities. It is based on the before and after evaluation of a trial led by a major stationery and office supplies company in which urban freight deliveries in central London made from a depot in the suburbs using diesel vehicles were replaced with the use of an urban micro-consolidation centre located in the delivery area together with the use of electrically-assisted cargo tricycles and electric vans. The results show that the total distance travelled and the CO2eq emissions per parcel delivered fell by 20% and 54% respectively as a result of this delivery system. However, the evaluation has also indicated that the distance travelled per parcel rose substantially in the City of London delivery area as a result of the electric vehicles having far smaller load limits in both weight and volume compared with diesel vans. But, at the same time, the trial system was able to virtually eliminate CO2eq emissions per parcel delivered in the City of London. The trial proved successful from the company's perspective in transport, environmental and financial terms. The company therefore decided to continue the operation beyond the end of the trial with it being officially launched during 2010.

  17. Thermal conductivity and electrical resistivity standard reference materials: tungsten SRM's 730 and 799, from 4 to 30000K. Final report

    International Nuclear Information System (INIS)

    Hust, J.G.; Giarratano, P.J.

    1975-09-01

    A historical review of the development of thermophysical Standard Reference Materials, SRM's, is given and selection criteria of SRM's are listed. Thermal conductivity and electrical resistivity data for arc cast and sintered tungsten are compiled, analyzed, and correlated. Recommended values of thermal conductivity (SRM 730) and electrical resistivity (SRM 799) for these lots of tungsten are presented for the range 4 to 3000 0 K

  18. Energy integration on multi-periods and multi-usages for hybrid electric and thermal powertrains

    International Nuclear Information System (INIS)

    Dimitrova, Zlatina; Maréchal, François

    2015-01-01

    The improvement of the efficiency of vehicle energy systems promotes an active search to find innovative solutions during the design process. This requires more accurate modeling of complex systems, which offers new ways to improve the design efficiency of energy systems. The vehicle is a highly dynamic system. The size and the efficiency of the convertors are dependent on the dynamic driving profile. In order to increase the energy efficiency, using energy integration techniques, an adapted methodology is required to choose the best points for the integrated system design. The idea is to clusterize the dynamic profile on typical multi-periods of the vehicle use. The energy system design is then optimized for these typical multi-periods. In this article a new methodology is applied on hybrid electric vehicles, in order to define the energy integrated powertrain configuration of the vehicle. The energy recovery potential of a single stage Organic Rankine Cycle for a thermal engine in combination with a hybrid electric powertrain is assessed for different drive cycles profiles and comfort situations. After the energy integration, a multi-objective optimization is applied to define the optimal design of a hybrid electric vehicle with a waste heat recovery system. - Highlights: • K-means algorithm transforms the dynamic driving profile on static multi-periods. • The clusters represent the typical powertrain use and size the heat recovery utility. • The maximal heat recovery potential on thermal powertrains is 11% for urban driving. • The maximal heat recovery potential on hybrid electric powertrains is 5%. • Engine downsizing increases heat recovery potential on hybrid electric powertrains

  19. Electric protections based in microprocessors in power plants; Protecciones electricas basadas en microprocesadores en centrales generadoras

    Energy Technology Data Exchange (ETDEWEB)

    Libreros, Domitilo; Castanon Jimenez, Jose Ismael [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1988-12-31

    This article is centered around the substitution of the conventional electric protections of a power plant in connection type unit for protections based in microprocessors. A general model of conventional protection of a power plant is described and the number of analogic and digital signals that intervene in that model are quantified. A model is setup for power plant protection with microprocessors, analyzing each one of the modules that would form it. Finally, the algorithms to carry on such protection are presented. [Espanol] Este articulo se centra en torno a la sustitucion de las protecciones electricas convencionales de una central generadora en conexion tipo unidad por protecciones basadas en microprocesadores. Se describe el modelo general de proteccion convencional de una central generadora y se cuantifica el numero de senales analogicas y digitales que interviene en dicho modelo. Se propone un modelo para proteccion de centrales generadoras mediante microprocesadores, analizandose cada uno de los modulos que lo conformarian. Finalmente, se presentan los algoritmos para realizar dicha proteccion.

  20. Electric protections based in microprocessors in power plants; Protecciones electricas basadas en microprocesadores en centrales generadoras

    Energy Technology Data Exchange (ETDEWEB)

    Libreros, Domitilo; Castanon Jimenez, Jose Ismael [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    This article is centered around the substitution of the conventional electric protections of a power plant in connection type unit for protections based in microprocessors. A general model of conventional protection of a power plant is described and the number of analogic and digital signals that intervene in that model are quantified. A model is setup for power plant protection with microprocessors, analyzing each one of the modules that would form it. Finally, the algorithms to carry on such protection are presented. [Espanol] Este articulo se centra en torno a la sustitucion de las protecciones electricas convencionales de una central generadora en conexion tipo unidad por protecciones basadas en microprocesadores. Se describe el modelo general de proteccion convencional de una central generadora y se cuantifica el numero de senales analogicas y digitales que interviene en dicho modelo. Se propone un modelo para proteccion de centrales generadoras mediante microprocesadores, analizandose cada uno de los modulos que lo conformarian. Finalmente, se presentan los algoritmos para realizar dicha proteccion.

  1. Intrinsic and extrinsic electrical and thermal transport of bulk black phosphorus

    Science.gov (United States)

    Hu, Sile; Xiang, Junsen; Lv, Meng; Zhang, Jiahao; Zhao, Hengcan; Li, Chunhong; Chen, Genfu; Wang, Wenhong; Sun, Peijie

    2018-01-01

    We report a comprehensive investigation of the electrical, thermal, and thermoelectric transport properties of bulk single-crystalline black phosphorus in wide temperature (2-300 K) and field (0-9 T) ranges. Electrical transport below T ≈ 250 K is found to be dominated by extrinsic hole-type charge carriers with large mobility exceeding 104 cm2/V s at low temperatures. While thermal transport measurements reveal an enhanced in-plane thermal conductivity maximum κ = 180 W/m K at T ≈ 25 K, it appears still to be largely constrained by extrinsic phonon scattering processes, e.g., the electron-phonon process, in addition to intrinsic umklapp scattering. The thermoelectric power and Nernst effect seem to be strongly influenced by ambipolar transport of charge carriers with opposite signs in at least the high-temperature region above 200 K, which diminishes the thermoelectric power factor of this material. Our results provide a timely update to the transport properties of bulk black phosphorus for future fundamental and applied research.

  2. Energy savings and increased electric vehicle range through improved battery thermal management

    International Nuclear Information System (INIS)

    Smith, Joshua; Hinterberger, Michael; Schneider, Christoph; Koehler, Juergen

    2016-01-01

    Lithium-ion cells are temperature sensitive: operation outside the optimal operating range causes premature aging and correspondingly reduces vehicle range and battery system lifetime. In order to meet consumer demands for electric and hybrid-electric vehicle performance, especially in adverse climates, a battery thermal management system (BTMS) is often required. This work presents a novel experimental method for analyzing BTMS using three sample cooling plate concepts. For each concept, the input parameters (ambient temperature, coolant temperature and coolant flow rate) are varied and the resulting effect on the average temperature and temperature distribution across and between cells is compared. Additionally, the pressure loss along the coolant path is utilized as an indicator of energy efficiency. Using the presented methodology, various cooling plate layouts optimized for production alternative techniques are compared to the state of the art. It is shown that these production-optimized cooling plates provide sufficient thermal performance with the additional benefit of mechanical integration within the battery and/or vehicle system. It is also shown that the coolant flow influences battery cell thermal behavior more than the solid material and that pressure drop is more sensitive to geometrical changes in the cooling plate than temperature changes at the module.

  3. New Electro-Thermal Battery Pack Model of an Electric Vehicle

    Directory of Open Access Journals (Sweden)

    Muhammed Alhanouti

    2016-07-01

    Full Text Available Since the evolution of the electric and hybrid vehicle, the analysis of batteries’ characteristics and influence on driving range has become essential. This fact advocates the necessity of accurate simulation modeling for batteries. Different models for the Li-ion battery cell are reviewed in this paper and a group of the highly dynamic models is selected for comparison. A new open circuit voltage (OCV model is proposed. The new model can simulate the OCV curves of lithium iron magnesium phosphate (LiFeMgPO4 battery type at different temperatures. It also considers both charging and discharging cases. The most remarkable features from different models, in addition to the proposed OCV model, are integrated in a single hybrid electrical model. A lumped thermal model is implemented to simulate the temperature development in the battery cell. The synthesized electro-thermal battery cell model is extended to model a battery pack of an actual electric vehicle. Experimental tests on the battery, as well as drive tests on the vehicle are performed. The proposed model demonstrates a higher modeling accuracy, for the battery pack voltage, than the constituent models under extreme maneuver drive tests.

  4. Vibration, buckling and smart control of microtubules using piezoelectric nanoshells under electric voltage in thermal environment

    Energy Technology Data Exchange (ETDEWEB)

    Farajpour, A., E-mail: ariobarzan.oderj@gmail.com; Rastgoo, A.; Mohammadi, M.

    2017-03-15

    Piezoelectric nanomaterials such as zinc oxide (ZnO) are of low toxicity and have many biomedical applications including optical imaging, drug delivery, biosensing and harvesting biomechanical energy using hybrid nanogenerators. In this paper, the vibration, buckling and smart control of microtubules (MTs) embedded in an elastic medium in thermal environment using a piezoelectric nanoshell (PNS) are investigated. The MT and PNS are considered to be coupled by a filament network. The PNS is subjected to thermal loads and an external electric voltage which operates to control the mechanical behavior of the MT. Using the nonlocal continuum mechanics, the governing differential equations are derived. An exact solution is presented for simply supported boundary conditions. The differential quadrature method is also used to solve the governing equations for other boundary conditions. A detailed parametric study is conducted to investigate the effects of the elastic constants of surrounding medium and internal filament matrix, scale coefficient, electric voltage, the radius-to-thickness ratio of PNSs and temperature change on the smart control of MTs. It is found that the applied electric voltage can be used as an effective controlling parameter for the vibration and buckling of MTs.

  5. A β-cyclodextrin based binary dopant for polyaniline: Structural, thermal, electrical, and sensing performance

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Tanushree; Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon 425001, Maharashtra (India); Shimpi, Navinchandra G., E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Kalina, Mumbai 400098, Maharashtra (India)

    2017-06-15

    Highlights: • A binary dopant based on β-cyclodextrin has been proposed for PANI. • The binary dopant provided long term stability to electrically conducting PANI. • The β-cyclodextrin based binary dopant rendered PANI sensitive towards CO at RT. - Abstract: The effect of hydrochloric acid/β-cyclodextrin (HCl/β-CD) binary dopant on the morphological, thermal, electrical, and sensing properties of PANI was investigated and compared with those of the conventionally doped PANI. The PANI samples were characterized using FTIR, UV–Vis, {sup 1}H NMR, and FESEM. Significant changes were observed in the structural, thermal, and electrical character of PANI doped with the HCl/β-CD binary dopant. A higher doping level was obtained for the PANI-binary dopant system, as observed from its {sup 1}H NMR spectra. Moreover, the binary dopant imparted long-term stability to the sensor in its conductive form. In addition, the PANI-binary dopant system exhibited a significantly high gas response towards carbon monoxide gas at room temperature.

  6. Thermal stability and electrical conductivity in polyethers-molybdenum disulfide nanocomposites

    International Nuclear Information System (INIS)

    Mirabal, N.; Aguirre, P.; Santa Ana, M.A.; Benavente, E.; Gonzalez, Guillermo

    2003-01-01

    The intercalation of poly(ethylene oxide) (PEO), into molybdenum disulfide, like that of other electron pair donors, leads to mixed ionic-electronic conductors. At room temperature, intercalates show electrical and lithium-ion conductivities better than MoS 2 and bulk PEO composites, respectively. However, these products are known to be sensitive to temperature; indeed, in the range 80-100 deg. C an irreversible decrease of the electrical conductivity is observed. In order to investigate these features, the thermal behavior of a series of polyethers of different molecular weights (poly(ethylene glycol) (Mw 3400) and PEO with Mw in the range 10 4 -4x10 6 , pure and intercalated in MoS 2 , (Li x (MoS 2 )(polyether) y with x∼0.1 and y=1.1-1.5), was comparatively analyzed. Furthermore, the effect of thermal treatment of the sample on the electrical conductivity was studied for one of the intercalated products. Results indicate that irreversible changes, detected by both loss of weight and a significant conductivity lowering, are occurring in the range from about 100 deg. C to a temperature near to the decomposition point of the organic phase at about 350 deg. C

  7. Optimization of low temperature solar thermal electric generation with Organic Rankine Cycle in different areas

    International Nuclear Information System (INIS)

    Jing, Li; Gang, Pei; Jie, Ji

    2010-01-01

    The presented low temperature solar thermal electric generation system mainly consists of compound parabolic concentrators (CPC) and the Organic Rankine Cycle (ORC) working with HCFC-123. A novel design is proposed to reduce heat transfer irreversibility between conduction oil and HCFC-123 in the heat exchangers while maintaining the stability of electricity output. Mathematical formulations are developed to study the heat transfer and energy conversion processes and the numerical simulation is carried out based on distributed parameters. Annual performances of the proposed system in different areas of Canberra, Singapore, Bombay, Lhasa, Sacramento and Berlin are simulated. The influences of the collector tilt angle adjustment, the connection between the heat exchangers and the CPC collectors, and the ORC evaporation temperature on the system performance are investigated. The results indicate that the three factors have a major impact on the annual electricity output and should be the key points of optimization. And the optimized system shows that: (1) The annual received direct irradiance can be significantly increased by two or three times optimal adjustments even when the CPC concentration ratio is smaller than 3.0. (2) Compared with the traditional single-stage collectors, two-stage collectors connected with the heat exchangers by two thermal oil cycles can improve the collector efficiency by 8.1-20.9% in the simultaneous processes of heat collection and power generation. (3) On the use of the market available collectors the optimal ORC evaporation temperatures in most of the simulated areas are around 120 C. (author)

  8. Novel polymer composite having diamond particles and boron nitride platelets for thermal management of electric vehicle motors

    Science.gov (United States)

    Nakajima, Anri; Shoji, Atsushi; Yonemori, Kei; Seo, Nobuhide

    2016-02-01

    Thermal conductivities of silicone matrix polymers including fillers of diamond particles and/or hexagonal boron nitride (h-BN) platelets were systematically investigated in an attempt to find a thermal interface material (TIM) having high isotropic thermal conductivity and high electrical insulating ability to enable efficient heat dissipation from the motor coil ends of electric vehicles. The TIM with mixed fillers of diamond particles and h-BN platelets had a maximum thermal conductivity of 6.1 W m-1 K-1 that was almost isotropic. This is the highest value among the thermal conductivities of TIMs with silicone matrix polymer reported to date. The mechanism behind the thermal conductivity of the TIMs was also examined from the viewpoint of the change in the number of thermally conductive networks and/or a decrease in the thermal resistivity of junctions of neighboring diamond particles through the incorporation of h-BN platelets. The TIMs developed in this study will make it possible to manage the heat of electric motors and will help to popularize electric vehicles.

  9. Thermal and electric conductivity of Cu50Zr35Ti8Hf5Nb2 volume amorphous alloy

    International Nuclear Information System (INIS)

    Gavrenko, O.A.; Merisov, B.A.; Mikhajlova, T.N.; Molokanov, V.V.; Sologubenko, A.V.; Khadzhaj, G.Ya.

    1996-01-01

    The temperature dependences of thermal conductivity and electric resistance of the Cu 50 Zr 35 Ti 8 Hf 5 Nb 2 volume amorphous alloy experimentally studied within the temperature range of 1.8-240 K. The temperature dependence of electrical resistance is well described by the ratio, taking into account the electron scattering on the phonons and in the two-level systems

  10. Reflections about the cogeneration of electrical and thermal energy in conditions of Chisinau city, Republic of Moldova

    International Nuclear Information System (INIS)

    Musteata, Valentin

    2004-01-01

    The cogeneration of electrical and thermal energy in Chisinau city is implements on heat power plants HPP-1 and HPP - 2. The district heating, receiving thermal energy from these power plants, has a severe alternative from the autonomous heating system. The capabilities of reducing the cost of thermal energy produced by HPP-2 are analyzed and the paths of improvement of district heating are forecasted. (author)

  11. Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

    International Nuclear Information System (INIS)

    Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

    2016-01-01

    Highlights: • An integrated thermal management system is proposed for electric vehicle. • The parallel branch of battery chiller can supply additional cooling capacity. • Heat pipe performance on preheating mode is better than that on cooling mode. • Heat pipe heat exchanger is a feasible choice for battery thermal management. - Abstract: An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode.

  12. Thermal and electrical joint test for the helical field coils in the Advanced Toroidal Facility

    International Nuclear Information System (INIS)

    Brown, R.L.; Johnson, R.L.

    1985-01-01

    Initial feasibility studies of a number of configurations for the Advanced Toroidal Facility (ATF) resulted in the selection of a resistive copper continuous-coil torsatron as the optimum device considering the physics program, cost, and schedule. Further conceptual design work was directed toward optimization of this configuration and, if possible, a shorter schedule. It soon became obvious that in order to shorten the schedule, a number of design and fabrication activities should proceed in parallel. This was most critical for the vacuum vessel and the helical field (HF) coils. If the HF coils were wound in place on a completed vacuum vessel, the overall schedule would be significantly (greater than or equal to12 months) longer. The approach of parallel scheduel paths requires that the HF coils be segmented into parts of less than or equal to180 0 of poloidal angle and that joints be made on a turn-by-turn basis when the segments are installed. It was obvious from the outset that the compact and complex geometry of the joint design presented a special challenge in the areas of reliability, assembly, maintenance, disassembly, and cost. Also, electrical, thermal, and force excursions are significant for these joints. A number of soldered, welded, brazed, electroplated, and bolted joints were evaluated. The evaluations examined fabrication feasibility and complexity, thermal-electrical performance at approximately two-thirds of the steady-state design conditions, and installation and assembly processes. Results of the thermal-electrical tests were analyzed and extrapolated to predict performance at peak design parameters. The final selection was a lap-type joint clamped with insulated bolts that pass through the winding packing. 3 refs., 4 figs

  13. Fabrication of dense yttrium oxyfluoride ceramics by hot pressing and their mechanical, thermal, and electrical properties

    Science.gov (United States)

    Tahara, Ryuki; Tsunoura, Toru; Yoshida, Katsumi; Yano, Toyohiko; Kishi, Yukio

    2018-06-01

    Excellent corrosion-resistant materials have been strongly required to reduce particle contamination during the plasma process in semiconductor production. Yttrium oxyfluoride can be a candidate as highly corrosion-resistant material. In this study, three types of dense yttrium oxyfluoride ceramics with different oxygen contents, namely, YOF, Y5O4F7 and Y5O4F7 + YF3, were fabricated by hot pressing, and their mechanical, thermal, and electrical properties were evaluated. Y5O4F7 ceramics showed an excellent thermal stability up to 800 °C, a low loss factor, and volume resistivity comparable to conventional plasma-resistant oxides, such as Y2O3. From these results, yttrium oxyfluoride ceramics are strongly suggested to be used as electrostatic chucks in semiconductor production.

  14. Thermal stress comparison in modular power converter topologies for smart transformers in the electrical distribution system

    DEFF Research Database (Denmark)

    Andresen, Markus; Ma, Ke; Liserre, Marco

    2015-01-01

    A Smart Transformer (ST) can cover an important managing role in the future electrical distribution grid. For the moment, the reliability and cost are not competitive with traditional transformers and create a barrier for its application. This work conduct detail designs and analysis...... for a promising modular ST solution, which is composed of Modular Multi-level converter, Quad Active Bridge DC-DC converters, and two-level voltage source converters. The focus is put on the loading conditions and thermal stress of power semiconductor devices in order to discover critical parts of the whole...... system when performing various mission profiles in the realistic distribution grid. It is concluded that the thermal stress for all stages is low during normal operation and especially the isolation stage is stressed least....

  15. Electricity supply from thermal power plants and alternative sources at the Adriatic coast

    International Nuclear Information System (INIS)

    Kurek, J.

    1999-01-01

    The Croatian coastline with its numerous islands offers the most appropriate region in the whole of Croatia for the realisation of energy supply from alternative sources as a substitute for the electricity supplied from coal-driven thermal power plants, not only from the point of view of energy but also financial results. Investment costs of a 100 MW thermal power plant served for the estimation of results which would be achieved with the introduction of alternative sources (the sun, small hydro power plants and biomass) as well as for the rationalisation of consumption and savings of the existing energy sources. The alternative programmes can be conducted partially and the investments financed from savings. However, without a systematic solution for the whole country no significant results can be expected. (author)

  16. Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments

    KAUST Repository

    Salas Villaseñor, Ana L.

    2014-06-01

    Thin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.

  17. Evaluation of electrical, structural, thermal and optical properties of Co_3O_4 semiconductor

    International Nuclear Information System (INIS)

    Dias, Jeferson A.; Maestrelli, Sylma C.; Morelli, Marcio R.

    2016-01-01

    Among the new semiconductors, the tricobalt tetraoxide is a material of increasing interest; nevertheless, there is a limited number of studies about its properties. Thus, this work has investigated the structural, thermal, optical and electronic properties of Co_3O_4 and its correlation with structure and microstructure. For that, the commercial material was characterized by X-ray diffraction, thermal analysis, diffuse reflectance, FTIR and impedance spectroscopy. The results have shown that the assessed Co_3O_4 has non-stoichiometric spinel structure, presenting a band gap energy capable to completely absorb the visible spectra (1.75 eV). Furthermore, it can be visualized in infrared spectra the bands related to Co-O bonds. The activation energy of electric conduction was 0.35 eV related to the hopping mechanism. Therefore, the results confirm the potentiality of use of Co_3O_4 in optoelectronic devices due to its promising properties for technological utilization. (author)

  18. Improved electrical stability of CdS thin film transistors through Hydrogen-based thermal treatments

    KAUST Repository

    Salas Villaseñ or, Ana L.; Mejia, Israel I.; Sotelo-Lerma, Mé rida; Guo, Zaibing; Alshareef, Husam N.; Quevedo-Ló pez, Manuel Angel Quevedo

    2014-01-01

    Thin film transistors (TFTs) with a bottom-gate configuration were fabricated using a photolithography process with chemically bath deposited (CBD) cadmium sulfide (CdS) films as the active channel. Thermal annealing in hydrogen was used to improve electrical stability and performance of the resulting CdS TFTs. Hydrogen thermal treatments results in significant V T instability (V T shift) improvement while increasing the I on/I off ratio without degrading carrier mobility. It is demonstrated that after annealing V T shift and I on/I off improves from 10 V to 4.6 V and from 105 to 10 9, respectively. Carrier mobility remains in the order of 14.5 cm2 V s-1. The reduced V T shift and performance is attributed to a reduction in oxygen species in the CdS after hydrogen annealing, as evaluated by Fourier transform infrared spectroscopy (FTIR). © 2014 IOP Publishing Ltd.

  19. Characterization of solar thermal concepts for electricity generation: Volume 1, Analyses and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, T.A.; Dirks, J.A.; Brown, D.R.; Drost, M.K.; Antoniac, Z.A.; Ross, B.A.

    1987-03-01

    This study is aimed at providing a relative comparison of the thermodynamic and economic performance in electric applications of several concepts that have been studied and developed in the DOE solar thermal program. Since the completion of earlier systems comparison studies in the late 1970's, there have been a number of years of progress in solar thermal technology. This progress has included development of new solar components, improvements in component and system design detail, construction of working systems, and collection of operating data on the systems. This study provides an updating of the expected performance and cost of the major components and the overall system energy cost for the concepts evaluated. The projections in this study are for the late 1990's time frame, based on the capabilities of the technologies that could be expected to be achieved with further technology development.

  20. An improved theoretical electrochemical-thermal modelling of lithium-ion battery packs in electric vehicles

    Science.gov (United States)

    Amiribavandpour, Parisa; Shen, Weixiang; Mu, Daobin; Kapoor, Ajay

    2015-06-01

    A theoretical electrochemical thermal model combined with a thermal resistive network is proposed to investigate thermal behaviours of a battery pack. The combined model is used to study heat generation and heat dissipation as well as their influences on the temperatures of the battery pack with and without a fan under constant current discharge and variable current discharge based on electric vehicle (EV) driving cycles. The comparison results indicate that the proposed model improves the accuracy in the temperature predication of the battery pack by 2.6 times. Furthermore, a large battery pack with four of the investigated battery packs in series is simulated in the presence of different ambient temperatures. The simulation results show that the temperature of the large battery pack at the end of EV driving cycles can reach to 50 °C or 60 °C in high ambient temperatures. Therefore, thermal management system in EVs is required to maintain the battery pack within the safe temperature range.

  1. Inspection maintenance and planning of shutdown in thermal electric generating plants

    International Nuclear Information System (INIS)

    Dezordi, W.L.; Correa, D.A.; Kina, M.

    1984-01-01

    The schedule shutdown of an industrial plant and, more specifically, of an electrical generating station, is becoming increasingly important. The major parameters to be taken into account for the planning of such a shutdown are basically of economic-financial nature such as costs of the related services (materials, equipment, manpower, etc), loss of revenue caused by the station's shutdown as well as by the station availability, and other requirements expected from it by the Load Dispatch and consumers. Improving the equipment's performances and the station's availability are the fundamental objectives to be strived for. The authors present in this paper, in an abridged form, the planning tools used for thermal electric generating plants shutdowns for inspections, maintenance and design changes implementation. (Author) [pt

  2. The influence of surface functionalisation on the electrical properties and thermal stability of nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Welch, Joseph O; Li, Pei; Chaudhary, Aysha; Edgington, Robert; Jackman, Richard B., E-mail: r.jackman@ucl.ac.uk [London Centre for Nanotechnology and the Department of Electronic and Electrical Engineering, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom)

    2014-10-07

    Detonation nanodiamond (ND) has recently emerged as a useful new class of diamond material. However, to date there has been little investigation of the electrical properties of this material. Due to the nanoscale dimensions, the surface functionalisation of the individual ND is of particular importance to the characteristics of ND films. Here, hydrogen and oxygen termination of ND, verified using Fourier transform infrared spectroscopy, are shown to strongly influence the electronic properties of NDs. Hydrogen terminated ND exhibiting a far greater resilience to thermal decomposition when compared to the oxygen terminated NDs. Moreover, H-NDs also displayed so-called “surface conductivity,” a property displayed by hydrogen-terminated bulk diamond films, whilst O-NDs display properties high resistivity. These results indicate that under the correct conditions ND layers can display similar electrical properties to “bulk” diamond thin films.

  3. Day-Ahead Self-Scheduling of Thermal Generator in Competitive Electricity Market Using Hybrid PSO

    DEFF Research Database (Denmark)

    Pindoriya, N.M.; Singh, Sri Niwas; Østergaard, Jacob

    2009-01-01

    in day-ahead energy market subject to operational constraints and 2) at the same time, to minimize the risk due to uncertainty in price forecast. Therefore, it is a conflicting biobjective optimization problem which has both binary and continuous optimization variables considered as constrained mixed......This paper presents a hybrid particle swarm optimization algorithm (HPSO) to solve the day-ahead selfscheduling for thermal power producer in competitive electricity market. The objective functions considered to model the selfscheduling problem are: 1) to maximize the profit from selling energy...... integer nonlinear programming. To demonstrate the effectiveness of the proposed method for self-scheduling in a dayahead energy market, the locational margin price (LMP) forecast uncertainty in PJM electricity market is considered. An adaptive wavelet neural network (AWNN) is used to forecast the dayahead...

  4. Microstructural evolution of pipelines for thermal electric power plants after a prolongated operation

    International Nuclear Information System (INIS)

    Twentyman, M.; Rosetti, R.; Porta, G.

    1991-01-01

    The study of failures originated in pipelines for thermal electric power plants allows an evaluation of the limit microstructural conditions that turn the system to critical conditions. A set of pipe samples with different microsctructural evolution which had been affected by direct flame were prepared. The samples were taken close to failures, away from them, from out of use pipes, etc. Metallographic studies were carried out using optical microscopy and scanning electron microscopy. Phase distribution, morphology and their relation with the different stages of aging were observed. (Author) [es

  5. A General Model for Thermal, Hydraulic and Electric Analysis of Superconducting Cables

    CERN Document Server

    Bottura, L; Rosso, C

    2000-01-01

    In this paper we describe a generic, multi-component and multi-channel model for the analysis of superconducting cables. The aim of the model is to treat in a general and consistent manner simultaneous thermal, electric and hydraulic transients in cables. The model is devised for most general situations, but reduces in limiting cases to most common approximations without loss of efficiency. We discuss here the governing equations, and we write them in a matrix form that is well adapted to numerical treatment. We finally demonstrate the model capability by comparison with published experimental data on current distribution in a two-strand cable.

  6. Thermal, optical, and electrical engineering of an innovative tunable white LED light engine

    Science.gov (United States)

    Trivellin, Nicola; Meneghini, Matteo; Ferretti, Marco; Barbisan, Diego; Dal Lago, Matteo; Meneghesso, Gaudenzio; Zanoni, Enrico

    2014-02-01

    Color temperature, intensity and blue spectrum of the light affects the ganglion receptors in human brain stimulating the human nervous system. With this work we review different methods for obtaining tunable light emission spectra and propose an innovative white LED lighting system. By an in depth study of the thermal, electrical and optical characteristics of GaN and GaP based compound semiconductors for optoelectronics a specific tunable spectra has been designed. The proposed tunable white LED system is able to achieve high CRI (above 95) in a large CCT range (3000 - 5000K).

  7. Electrical Thermal Network for Direct Contact Membrane Distillation Modeling and Analysis

    KAUST Repository

    Karam, Ayman M.

    2015-02-04

    Membrane distillation is an emerging water distillation technology that offers several advantages compared to conventional water desalination processes. Although progress has been made to model and understand the physics of the process, many studies are based on steady-state assumptions or are computationally not appropriate for real time control. This paper presents the derivation of a novel dynamical model, based on analogy between electrical and thermal systems, for direct contact membrane distillation (DCMD). The proposed model captures the dynamics of temperature distribution and distilled water flux. To demonstrate the adequacy of the proposed model, validation with transient and steady-state experimental data is presented.

  8. MECHANICAL, ELECTRICAL, AND THERMAL PROPERTIES OF MALEIC ANHYDRIDE MODIFIED RICE HUSK FILLED PVC COMPOSITES

    OpenAIRE

    Navin Chand; Bhajan Das Jhod

    2008-01-01

    Unmodified and modified rice husk powder filled PVC composites were prepared having different amounts of rice husk powder. Mechanical, thermal, and electrical properties of these composites were determined. The tensile strength of rice husk powder PVC composites having 0, 10, 20, 30, and 40 weight percent of rice husk powder was found to be 33.9, 19.4, 18.1, 14.6, and 9.5 MPa, respectively. Adding of maleic anhydride- modified rice husk powder improved the tensile strength of rice husk powder...

  9. Effects of rapid thermal annealing on the optical and electrical properties of InN epilayers

    International Nuclear Information System (INIS)

    Shu, G W; Wu, P F; Liu, Y W; Wang, J S; Shen, J L; Lin, T Y; Pong, P J; Chi, G C; Chang, H J; Chen, Y F; Lee, Y C

    2006-01-01

    We studied the optical and electrical properties of InN epilayers with rapid thermal annealing (RTA). The intensity of the photoluminescence (PL) and the carrier mobility were found to increase as the temperature of RTA was increased. We suggest that the formation of compensating acceptors (indium vacancies) after RTA is responsible for the improvement of the quality in InN. The dependence of the PL emission peak on carrier concentration provides a possible method for estimating the carrier concentration in degenerate InN. (letter to the editor)

  10. Electrical resistivity and thermal conductivity of liquid aluminum in the two-temperature state

    Science.gov (United States)

    Petrov, Yu V.; Inogamov, N. A.; Mokshin, A. V.; Galimzyanov, B. N.

    2018-01-01

    The electrical resistivity and thermal conductivity of liquid aluminum in the two-temperature state is calculated by using the relaxation time approach and structural factor of ions obtained by molecular dynamics simulation. Resistivity witin the Ziman-Evans approach is also considered to be higher than in the approach with previously calculated conductivity via the relaxation time. Calculations based on the construction of the ion structural factor through the classical molecular dynamics and kinetic equation for electrons are more economical in terms of computing resources and give results close to the Kubo-Greenwood with the quantum molecular dynamics calculations.

  11. Early colonization of thermal niches in a silica-depositing hot spring in central Tibet.

    Science.gov (United States)

    Lau, C Y; Aitchison, J C; Pointing, S B

    2008-03-01

    Thermophilic microbial mats dominated by the anoxygenic phototroph Roseiflexus castenholzii commonly develop around sinter-depositing geysers in the Daggyai Tso geothermal field of central Tibet. In this study we used morphological and molecular genetic techniques to reveal a diverse pioneer biofilm community including both archaea and bacteria involved in early colonization of such thermal niches at temperatures ranging from 46 to 77 degrees C. Sinter precipitation and biomineralization were evident at all locations, but the latter was selective between taxa and most evident on filamentous cells. Evidence for possible indirect biosignatures from biofilms overwhelmed by sinter deposition was found. Succession to a mature community appeared to relate to the growth rate for key taxa outpacing that of silicification within an optimum temperature range of 54-61 degrees C. The thin surface layer of silicification-resistant cyanobacteria that developed on the surface of mature mats may play a role in preventing biomineralization of the susceptible R. castenholzii beneath within these communities.

  12. The occurrence of single and multiple organ dysfunction in pediatric electrical versus other thermal burns.

    Science.gov (United States)

    Hundeshagen, Gabriel; Wurzer, Paul; Forbes, Abigail A; Voigt, Charles D; Collins, Vanessa N; Cambiaso-Daniel, Janos; Finnerty, Celeste C; Herndon, David N; Branski, Ludwik K

    2017-05-01

    Multiple organ failure (MOF) is a major contributor to morbidity and mortality in burned children. While various complications induced by electrical injuries have been described, the incidence and severity of single organ failure (SOF) and MOF associated with this type of injury are unknown. The study was undertaken to compare the incidence and severity of SOF and MOF as well as other complications between electrically and thermally burned children. Between 2001 and 2016, 288 pediatric patients with electrical burns (EB; n = 96) or thermal burns (CTR; n = 192) were analyzed in this study. Demographic data; length of hospitalization; and number and type of operations, amputations, and complications were statistically analyzed. Incidence of SOF and MOF was assessed using the DENVER2 classification in an additive mixed model over time. Compound scores and organ-specific scores for lung, heart, kidney, and liver were analyzed. Serum cytokine expression profiles of both groups were also compared over time. Significance was accepted at p in age (CTR, 11 ± 5 years, vs EB, 11 ± 5 years), percent total body surface area burned (CTR, 33% ± 25%, vs EB, 32 ± 25%), and length of hospitalization (CTR, 18 ± 26 days, vs EB, 18 ± 21 days). The percentage of high-voltage injury in the EB group was 64%. The incidence of MOF was lower in the EB group (2 of 96 [2.1%]) than the CTR group (20 of 192 [10.4%]; p The incidence of single organ failure was comparable between groups. Incidence of pulmonary failure was comparable in both groups, but incidence of inhalation injury was significantly higher in the CTR group (p in the EB group had more amputations (p the groups. Serum cytokine expression profiles were also comparable between the groups. In pediatric patients, electrical injury is associated with a lower incidence of MOF than other thermal burns. Early and radical debridement of nonviable tissue is crucial to improve outcomes in the electrical burn patient population

  13. Experimental facilities for PEC reactor design central channel test loop: CPC-1 - thermal shocks loop: CEDI

    International Nuclear Information System (INIS)

    Calvaresi, C.; Moreschi, L.F.

    1983-01-01

    PEC (Prova Elementi di Combustibile: Fuel Elements Test) is an experimental fast sodium-cooled reactor with a power of 120 MWt. This reactor aims at studying the behaviour of fuel elements under thermal and neutron conditions comparable with those existing in fast power nuclear facilities. Given the particular structure of the core, the complex operations to be performed in the transfer cell and the strict operating conditions of the central channel, two experimental facilities, CPC-1 and CEDI, have been designed as a support to the construction of the reactor. CPC-1 is a 1:1 scale model of the channel, transfer-cell and loop unit of the channel, whereas CEDI is a sodium-cooled loop which enables to carry out tests of isothermal endurance and thermal shocks on the group of seven forced elements, by simulating the thermo-hydraulic and mechanical conditions existing in the reactor. In this paper some experimental test are briefy discussed and some facilities are listed, both for the CPC-1 and for the CEDI. (Auth.)

  14. Incorporating Water Boiling in the Numerical Modelling of Thermal Remediation by Electrical Resistance Heating

    Science.gov (United States)

    Molnar, I. L.; Krol, M.; Mumford, K. G.

    2017-12-01

    Developing numerical models for subsurface thermal remediation techniques - such as Electrical Resistive Heating (ERH) - that include multiphase processes such as in-situ water boiling, gas production and recovery has remained a significant challenge. These subsurface gas generation and recovery processes are driven by physical phenomena such as discrete and unstable gas (bubble) flow as well as water-gas phase mass transfer rates during bubble flow. Traditional approaches to multiphase flow modeling soil remain unable to accurately describe these phenomena. However, it has been demonstrated that Macroscopic Invasion Percolation (MIP) can successfully simulate discrete and unstable gas transport1. This has lead to the development of a coupled Electro Thermal-MIP Model2 (ET-MIP) capable of simulating multiple key processes in the thermal remediation and gas recovery process including: electrical heating of soil and groundwater, water flow, geological heterogeneity, heating-induced buoyant flow, water boiling, gas bubble generation and mobilization, contaminant mass transport and removal, and additional mechanisms such as bubble collapse in cooler regions. This study presents the first rigorous validation of a coupled ET-MIP model against two-dimensional water boiling and water/NAPL co-boiling experiments3. Once validated, the model was used to explore the impact of water and co-boiling events and subsequent gas generation and mobilization on ERH's ability to 1) generate, expand and mobilize gas at boiling and NAPL co-boiling temperatures, 2) efficiently strip contaminants from soil during both boiling and co-boiling. In addition, a quantification of the energy losses arising from steam generation during subsurface water boiling was examined with respect to its impact on the efficacy of thermal remediation. While this study specifically targets ERH, the study's focus on examining the fundamental mechanisms driving thermal remediation (e.g., water boiling) renders

  15. Financing alternatives and incentives for solar-thermal central-receiver systems

    Energy Technology Data Exchange (ETDEWEB)

    Bos, P.B.

    1982-07-01

    As a result of various recently enacted incentive and regulatory legislation combined with the new administration policy and budgetary guidelines, the commercialization of solar thermal central receiver systems will involve financing alternatives other than conventional utility financing. This study was conducted to identify these potential financing alternatives and the associated requirements and impacts on the Department of Energy program. Based upon this analysis, it is concluded that the current alternative financing window is extremely short (through 1985), and that an extension or at the least a gradual phasing out, of the solar tax credits is necessary for the successful transfer of the central receiver technology to the private sector. Furthermore, throughout this time period, continued government support of the R and D activities is necessary to provide the necessary confidence in this technology for the private (financial) sector to underwrite this technology transfer. Consequently, even though the central receiver technology shows high promise for replacing a significant fraction of the oil/gas-fired utility industry peaking and intermediate generation, the current readiness status of this technology still requires further direct and indirect government support for a successful technology transfer. The direct government research and development support will provide the basis for a technological readiness and confidence, whereas the indirect tax incentive support serves to underwrite the extraordinary risks associated with the technology transfer. These support requirements need only be limited to and decreasing during this technology transfer phase, since as the systems approach successful full-scale commercialization, the extraordinary risks will be gradually eliminated. At the time of commercialization the system's value should be on a par with the installed system's cost.

  16. Impact of a 1,000-foot thermal mixing zone on the steam electric power industry

    International Nuclear Information System (INIS)

    Veil, J.A.

    1994-04-01

    Thermal discharge requirements for power plants using once-through cooling systems are based on state water quality standards for temperatures that must be met outside of designated mixing zones. This study evaluates the impact of limiting the extent of thermal mixing zones. This study evaluates the impact of limiting the extent of thermal mixing zones to no more than 1,000 feet from the discharge point. Data were collected from 79 steam electric plants. Of the plants currently using once-through cooling systems, 74% could not meet current thermal standards at the edge of a 1,000-foot mixing zone. Of this total, 68% would retrofit cooling towers, and 6% would retrofit diffusers. The estimated nationwide capital cost for retrofitting plants that could not meet current thermal standards at the edge of a 1,000-foot mixing zone is $21.4 billion. Conversion of a plant from once-through cooling to cooling towers or addition of diffusers would result in a lower energy output from that plant. For the affected plants, the total estimated replacement cost would be $370 to $590 million per year. Some power companies would have to construct new generating capacity to meet the increased energy demand. The estimated nationwide cost of this additional capacity would be $1.2 to $4.8 billion. In addition to the direct costs associated with compliance with a 1,000-foot mixing zone limit, other secondary environmental impacts would also occur. Generation of the additional power needed would increase carbon dioxide emissions by an estimated 8.3 million tons per year. In addition, conversion from once-through cooling systems to cooling towers at affected plants would result in increased evaporation of about 2.7 million gallons of water per minute nationwide

  17. Turbine model for the Laguna Verde nucleo electric central based in the RELAP code

    International Nuclear Information System (INIS)

    Cortes M, F.S.; Ramos P, J.C.; Salazar S, E.; Chavez M, C.

    2003-01-01

    The Nuclear Power stations as Laguna Verde occupy at the present time a place every time but important as non pollutant alternative, economic and trusty to generate electricity. It is for it that the Group of Nuclear Engineering of the Engineering Faculty (GrlNFI) of the National Autonomous University of Mexico (UNAM) it develops investigation projects applied to Nuclear Centrals. One of the projects in process is the development of a Classroom simulator, which it can configures to consent to diverse models of nuclear systems with training purposes in normal operation, or, to consent to specialized nuclear codes for the analysis of transitory events and have a severe accident. This work describes the development, implementation and it proves of a simplified model of the Main turbine to be integrated to the group of models of the Classroom simulator. It is part of the current effort of GrlNFI guided to obtain a representation of all the dynamic models necessary to simulate the Plant Balance of the Laguna Verde Central. It is included the development of the unfolding graphic which represent the modeling of the Main turbine, and of the control interface that allows the user to manipulate in simple way, direct and interactive this device during the training or the analysis. With this work it is wanted to contribute to the training of new technicians and to support the operation personnel of the Centrals. Also, the developed infrastructure is guided to contribute in the design and analysis of new Nuclear Power stations with the contribution of new computational tools for the visualization, simulation and process control. (Author)

  18. PREFACE: 1st International Symposium on Electrical Arc and Thermal Plasmas in Africa (ISAPA)

    Science.gov (United States)

    Andre, Pascal; Koalaga, Zacharie

    2012-02-01

    Logos of the University of Ouagadougou, ISAPA and Universite Blaise Pascal Africa (especially Sub-Saharan Africa) is a continent where electrification is at a low level. However, the development of the electrical power sector is a prerequisite for the growth of other industrial activities, that is to say for the social and economic development of African countries. Consequently, a large number of electrification projects (rural electrification, interconnection of different country's grids) takes place in many countries. These projects need expertise and make Africa a continent of opportunity for companies in different domains for business and research: energy; energetic production, transmission, distribution and protection of electricity; the supply of cable; the construction, engineering and expertise in the field of solar and wind power. The first International Symposium on electrical Arc and thermal Plasma in Africa (ISAPA) was held for the first time in Ouagadougou, Burkina Faso to progress and develop the research of new physical developments, technical breakthroughs, and ideas in the fields of electrical production and electrical applications. The ISAPA aims to encourage the advancement of the science and applications of electrical power transformation in Africa by bringing together specialists from many areas in Africa and the rest of the world. Such considerations have led us to define a Scientific Committee including representatives from many countries. This first meeting was an innovative opportunity for researchers and engineers from academic and industrial sectors to exchange views and knowledge. Both fundamental aspects such as thermal plasma, electrical arc, diagnostics and applied aspects as circuit breakers, ICP analyses, photovoltaic energy conversion and alternative energies, as well as space applications were covered. The Laboratory of Material and Environment (LAME) from Ouagadougou University and the Laboratory of Electric Arc and Thermal

  19. Solar cooling - comparative study between thermal and electrical use in industrial buildings

    Science.gov (United States)

    Badea, N.; Badea, G. V.; Epureanu, A.; Frumuşanu, G.

    2016-08-01

    The increase in the share of renewable energy sources together with the emphasis on the need for energy security bring to a spotlight the field of trigeneration autonomous microsystems, as a solution to cover the energy consumptions, not only for isolated industrial buildings, but also for industrial buildings located in urban areas. The use of solar energy for cooling has been taken into account to offer a cooling comfort in the building. Cooling and air- conditioned production are current applications promoting the use of solar energy technologies. Solar cooling systems can be classified, depending on the used energy, in electrical systems using mechanical compression chillers and systems using thermal compression by absorption or adsorption. This comparative study presents the main strengths and weaknesses of solar cooling obtained: i) through the transformation of heat resulted from thermal solar panels combined with adsorption chillers, and ii) through the multiple conversion of electricity - photovoltaic panels - battery - inverter - combined with mechanical compression chillers. Both solutions are analyzed from the standpoints of energy efficiency, dynamic performances (demand response), and costs sizes. At the end of the paper, experimental results obtained in the climatic condition of Galafi city, Romania, are presented.

  20. Investigation of Solar Hybrid Electric/Thermal System with Radiation Concentrator and Thermoelectric Generator

    Directory of Open Access Journals (Sweden)

    Edgar Arturo Chávez Urbiola

    2013-01-01

    Full Text Available An experimental study of a solar-concentrating system based on thermoelectric generators (TEGs was performed. The system included an electrical generating unit with 6 serially connected TEGs using a traditional semiconductor material, Bi2Te3, which was illuminated by concentrated solar radiation on one side and cooled by running water on the other side. A sun-tracking concentrator with a mosaic set of mirrors was used; its orientation towards the sun was achieved with two pairs of radiation sensors, a differential amplifier, and two servomotors. The hot side of the TEGs at midday has a temperature of around 200°C, and the cold side is approximately 50°C. The thermosiphon cooling system was designed to absorb the heat passing through the TEGs and provide optimal working conditions. The system generates 20 W of electrical energy and 200 W of thermal energy stored in water with a temperature of around 50°C. The hybrid system studied can be considered as an alternative to photovoltaic/thermal systems, especially in countries with abundant solar radiation, such as Mexico, China, and India.

  1. Performance evaluation and parametric choice criteria of a Brayton pumped thermal electricity storage system

    International Nuclear Information System (INIS)

    Guo, Juncheng; Cai, Ling; Chen, Jincan; Zhou, Yinghui

    2016-01-01

    A more realistic thermodynamic model of the pumped thermal electricity storage (PTES) system consisting of a Brayton cycle and a reverse Brayton cycle is proposed, where the internal and external irreversible losses are took into account and several important controlling parameters, e.g., the pressure ratio and heat flows of the two isobaric processes in the Brayton cycle, are introduced. Analytic expressions for the round trip efficiency and power output of the PTES system are derived. The general performance characteristics of the PTES system are revealed. The optimal relationship between the round trip efficiency and the power output is obtained. The influences of some important controlling parameters on the performance characteristics of the PTES system are discussed and the optimally operating regions of these parameters are determined. - Highlights: • A cycle model of the Brayton pumped thermal electricity storage system is proposed. • Internal and external irreversible losses are considered. • Maximum power output and efficiency of the system are calculated. • Optimum performance characteristics of the system are revealed. • Rational ranges of key controlling parameters are determined.

  2. Electrical equivalent thermal network for direct contact membrane distillation modeling and analysis

    KAUST Repository

    Karam, Ayman M.

    2016-09-19

    Membrane distillation (MD) is an emerging water desalination technology that offers several advantages compared to conventional desalination methods. Although progress has been made to model the physics of the process, there are two common limitations of existing models. Firstly, many of the models are based on the steady-state analysis of the process and secondly, some of the models are based on partial differential equations, which when discretized introduce many states which are not accessible in practice. This paper presents the derivation of a novel dynamic model, based on the analogy between electrical and thermal systems, for direct contact membrane distillation (DCMD). An analogous electrical thermal network is constructed and its elements are parameterized such that the response of the network models the DCMD process. The proposed model captures the spatial and temporal responses of the temperature distribution along the flow direction and is able to accurately predict the distilled water flux output. To demonstrate the adequacy of the proposed model, validation with time varying and steady-state experimental data is presented. (C) 2016 Elsevier Ltd. All rights reserved.

  3. Thermal fluctuation levels of magnetic and electric fields in unmagnetized plasma: The rigorous relativistic kinetic theory

    International Nuclear Information System (INIS)

    Yoon, P. H.; Schlickeiser, R.; Kolberg, U.

    2014-01-01

    Any fully ionized collisionless plasma with finite random particle velocities contains electric and magnetic field fluctuations. The fluctuations can be of three different types: weakly damped, weakly propagating, or aperiodic. The kinetics of these fluctuations in general unmagnetized plasmas, governed by the competition of spontaneous emission, absorption, and stimulated emission processes, is investigated, extending the well-known results for weakly damped fluctuations. The generalized Kirchhoff radiation law for both collective and noncollective fluctuations is derived, which in stationary plasmas provides the equilibrium energy densities of electromagnetic fluctuations by the ratio of the respective spontaneous emission coefficient and the true absorption coefficient. As an illustrative example, the equilibrium energy densities of aperiodic transverse collective electric and magnetic fluctuations in an isotropic thermal electron-proton plasmas of density n e are calculated as |δB|=√((δB) 2 )=2.8(n e m e c 2 ) 1/2 g 1/2 β e 7/4 and |δE|=√((δE) 2 )=3.2(n e m e c 2 ) 1/2 g 1/3 β e 2 , where g and β e denote the plasma parameter and the thermal electron velocity in units of the speed of light, respectively. For densities and temperatures of the reionized early intergalactic medium, |δB|=6·10 −18 G and |δE|=2·10 −16 G result

  4. Tuning the Electrical and Thermal Conductivities of Thermoelectric Oxides through Impurity Doping

    Science.gov (United States)

    Torres Arango, Maria A.

    Waste heat and thermal gradients available at power plants can be harvested to power wireless networks and sensors by using thermoelectric (TE) generators that directly transform temperature differentials into electrical power. Oxide materials are promising for TE applications in harsh industrial environments for waste heat recovery at high temperatures in air, because they are lightweight, cheaply produced, highly efficient, and stable at high temperatures in air. Ca3Co4O9(CCO) with layered structure is a promising p-type thermoelectric oxide with extrapolated ZT value of 0.87 in single crystal form [1]. However the ZT values for the polycrystalline ceramics remain low of ˜0.1-0.3. In this research, nanostructure engineering approaches including doping and addition of nanoinclusions were applied to the polycrystalline CCO ceramic to improve the energy conversion efficiency. Polycrystalline CCO samples with various Bi doping levels were prepared through the sol-gel chemical route synthesis of powders, pressing and sintering of the pellets. Microstructure features of Bi doped ceramic bulk samples such as porosity, development of crystal texture, grain boundary dislocations and segregation of Bi dopants at various grain boundaries are investigated from microns to atomic scale. The results of the present study show that the Bi-doping is affecting both the electrical conductivity and thermal conductivity simultaneously, and the optimum Bi doping level is strongly correlated with the microstructure and the processing conditions of the ceramic samples. At the optimum doping level and processing conditions of the ceramic samples, the Bi substitution of Ca results in the increase of the electrical conductivity, decrease of the thermal conductivity, and improvement of the crystal texture. The atomic resolution Scanning Transmission Electron Microscopy (STEM) Z-contrast imaging and the chemistry analysis also reveal the Bi-segregation at grain boundaries of CCO

  5. BUILDOUT AND UPGRADE OF CENTRAL EMERGENCY GENERATOR SYSTEM, GENERATOR 3 AND 4 ELECTRICAL INSTALLATION

    Energy Technology Data Exchange (ETDEWEB)

    Gary D. Seifert; G. Shawn West; Kurt S. Myers; Jim Moncur

    2006-07-01

    SECTION 01000—SUMMARY OF WORK PART 1—GENERAL 1.1 SUMMARY The work to be performed under this project consists of providing the labor, equipment, and materials to perform "Buildout and Upgrade of Central Emergency Generator System, Generator 3 and 4 Electrical Installation" for the National Aeronautics and Space Administration at the Dryden Flight Research Center (NASA/DFRC), Edwards, California 93523. All modifications to existing substations and electrical distribution systems are the responsibility of the contractor. It is the contractor’s responsibility to supply a complete and functionally operational system. The work shall be performed in accordance with these specifications and the related drawings. The work of this project is defined by the plans and specifications contained and referenced herein. This work specifically includes but is not limited to the following: Scope of Work - Installation 1. Install all electrical wiring and controls for new generators 3 and 4 to match existing electrical installation for generators 1 and 2 and in accordance with drawings. Contractor shall provide as-built details for electrical installation. 2. Install battery charger systems for new generators 3 and 4 to match existing battery charging equipment and installation for generators 1 and 2. This may require exchange of some battery charger parts already on-hand. Supply power to new battery chargers from panel and breakers as shown on drawings. Utilize existing conduits already routed to generators 3 and 4 to field route the new wiring in the most reasonable way possible. 3. Install electrical wiring for fuel/lube systems for new generators 3 and 4 to match existing installation for generators 1 and 2. Supply power to lube oil heaters and fuel system (day tanks) from panel and breakers as shown on drawings. Utilize existing conduits already routed to generators 3 and 4 to field route the new wiring in the most reasonable way possible. Add any conduits necessary to

  6. Thru-life impacts of driver aggression, climate, cabin thermal management, and battery thermal management on battery electric vehicle utility

    Science.gov (United States)

    Neubauer, Jeremy; Wood, Eric

    2014-08-01

    Battery electric vehicles (BEVs) offer the potential to reduce both oil imports and greenhouse gas emissions, but have a limited utility that is affected by driver aggression and effects of climate-both directly on battery temperature and indirectly through the loads of cabin and battery thermal management systems. Utility is further affected as the battery wears through life in response to travel patterns, climate, and other factors. In this paper we apply the National Renewable Energy Laboratory's Battery Lifetime Analysis and Simulation Tool for Vehicles (BLAST-V) to examine the sensitivity of BEV utility to driver aggression and climate effects over the life of the vehicle. We find the primary challenge to cold-climate BEV operation to be inefficient cabin heating systems, and to hot-climate BEV operation to be high peak on-road battery temperatures and excessive battery degradation. Active cooling systems appear necessary to manage peak battery temperatures of aggressive, hot-climate drivers, which can then be employed to maximize thru-life vehicle utility.

  7. Concentrating solar thermal power as a viable alternative in China's electricity supply

    International Nuclear Information System (INIS)

    Chung-Ling Chien, John; Lior, Noam

    2011-01-01

    Study of low-carbon and pollution renewable alternatives for China revealed that concentrating solar thermal (CST) electric power generation was underemphasized in China's renewable energy plan. The analysis shows the competitive viability of CST: (1) China has the key prerequisites to make CST power generation economical including high-quality insolation and appropriate land, (2) CST's proven history, scale, and dispatchability makes it a good utility-scale power option, especially in the economically underdeveloped Western regions, (3) while CST power is currently more expensive than coal-fired electricity on a nominal basis, when costs of externalities are accounted for, CST, at 11.4 US cents/kWh, can become 57% cheaper than scrubbed coal and 29% cheaper than nuclear power, (4) CST power continues dropping in cost due to economies of scale and technological improvements and can potentially realize a levelized electricity cost of around 4 cents/kWh within ten years, (5) it would significantly rise in competitiveness if and when China completes the extensive smart grid for connecting its solar-abundant western regions with the high-demand eastern regions, (6) CST has the potential to positively impact Western China's economy, but proper policy and deal structure must be in place to ensure that the local community shares the benefit. - Highlights: ► We analyze inclusion of concentrating solar thermal (CST) power in China. ► We find that CST needs emphasis in China's renewable energy plan. ► The analysis shows that CST is competitive with coal if externalities are considered. ► We recommend a policy that would develop CST power generation in western regions. ► This would be of significant benefit to Western China's economy and to China.

  8. Post-deposition control of ferroelastic stripe domains and internal electric field by thermal treatment

    Energy Technology Data Exchange (ETDEWEB)

    Feigl, L.; Iwanowska, M.; Sandu, C. S.; Setter, N. [Ceramics Laboratory, EPFL-Swiss Federal Institute of Technology, Lausanne, CH-1015 Switzerland (Switzerland); Janolin, P.-E. [Laboratoire Structures, Propriétés et Modélisation des Solides, UMR CNRS-École Centrale Paris, Grande Voie des Vignes, 92295 Châtenay-Malabry Cedex (France); Yamada, T. [Department of Materials, Physics and Energy Engineering, Nagoya University, Nagoya 464-8603 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan)

    2015-01-19

    The dependence of the formation of ferroelastic stripe domain patterns on the thermal history is investigated by detailed piezoresponse force microscopy and X-ray diffraction experiments after and during annealing of tensile strained tetragonal Pb(Ti,Zr)O{sub 3} epitaxial thin films on DyScO{sub 3} substrates. In particular, the ferroelastic pattern is reversibly interchanged between a cross-hatched and a stripe domain pattern if the films are cooled at different rates after annealing above the formation temperature of a-domains. Different types of 180° and non-180° patterns can be created, depending on the thermal treatment. The changes in the 180° domain structure and lattice parameters are attributed to a change of oxygen vacancy concentration, which results in a modification of the internal electric field and unit cell size, causing also a shift of T{sub C}. Thermal treatment is done on rhombohedral La:BiFeO{sub 3} thin films as well. It is observed that also in these films, appropriate heat treatment modifies the domain pattern and films with a stripe domain pattern can be created, confirming the general validity of the developed model.

  9. Aggregation of egg white proteins with pulsed electric fields and thermal processes.

    Science.gov (United States)

    Wu, Li; Zhao, Wei; Yang, Ruijin; Yan, Wenxu; Sun, Qianyan

    2016-08-01

    Pulsed electric field (PEF) processing is progressing towards application for liquid egg to ensure microbial safety. However, it usually causes protein aggregation, and the mechanism is still unclear. In this study, egg white protein was applied to investigate the changes in protein structure and mechanism of aggregates formation and a comparison was made with thermal treatment. Soluble protein content decreased with the increase of turbidity after both treatments. Fluorescence intensity and free sulfhydryl content were increased after being treated at 70 °C for 4 min. Less-remarkable changes of hydrophobicity were observed after PEF treatments (30 kV cm(-1) , 800 µs). Soluble and insoluble aggregates were observed by thermal treatment, and disulfide bonds were the main binding forces. The main components of insoluble aggregates formed by thermal treatment were ovotransferrin (30.58%), lysozyme (18.47%) and ovalbumin (14.20%). While only insoluble aggregates were detected during PEF processes, which consists of ovotransferrin (11.86%), lysozyme (21.11%) and ovalbumin (31.07%). Electrostatic interaction played a very important role in the aggregates formation. PEF had a minor impact on the structure of egg white protein. PEF had insignificant influence on heat-sensitive protein, indicating that PEF has potential in processing food with high biological activity and heat sensitive properties. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  10. Hybrids of Solar Sail, Solar Electric, and Solar Thermal Propulsion for Solar-System Exploration

    Science.gov (United States)

    Wilcox, Brian H.

    2012-01-01

    Solar sails have long been known to be an attractive method of propulsion in the inner solar system if the areal density of the overall spacecraft (S/C) could be reduced to approx.10 g/sq m. It has also long been recognized that the figure (precise shape) of useful solar sails needs to be reasonably good, so that the reflected light goes mostly in the desired direction. If one could make large reflective surfaces with reasonable figure at an areal density of approx.10 g/sq m, then several other attractive options emerge. One is to use such sails as solar concentrators for solar-electric propulsion. Current flight solar arrays have a specific output of approx. 100W/kg at 1 Astronomical Unit (AU) from the sun, and near-term advances promise to significantly increase this figure. A S/C with an areal density of 10 g/sq m could accelerate up to 29 km/s per year as a solar sail at 1 AU. Using the same sail as a concentrator at 30 AU, the same spacecraft could have up to approx. 45 W of electric power per kg of total S/C mass available for electric propulsion (EP). With an EP system that is 50% power-efficient, exhausting 10% of the initial S/C mass per year as propellant, the exhaust velocity is approx. 119 km/s and the acceleration is approx. 12 km/s per year. This hybrid thus opens attractive options for missions to the outer solar system, including sample-return missions. If solar-thermal propulsion were perfected, it would offer an attractive intermediate between solar sailing in the inner solar system and solar electric propulsion for the outer solar system. In the example above, both the solar sail and solar electric systems don't have a specific impulse that is near-optimal for the mission. Solar thermal propulsion, with an exhaust velocity of the order of 10 km/s, is better matched to many solar system exploration missions. This paper derives the basic relationships between these three propulsion options and gives examples of missions that might be enabled by

  11. Electrical conductivity measurement of excised human metastatic liver tumours before and after thermal ablation.

    Science.gov (United States)

    Haemmerich, Dieter; Schutt, David J; Wright, Andrew W; Webster, John G; Mahvi, David M

    2009-05-01

    We measured the ex vivo electrical conductivity of eight human metastatic liver tumours and six normal liver tissue samples from six patients using the four electrode method over the frequency range 10 Hz to 1 MHz. In addition, in a single patient we measured the electrical conductivity before and after the thermal ablation of normal and tumour tissue. The average conductivity of tumour tissue was significantly higher than normal tissue over the entire frequency range (from 4.11 versus 0.75 mS cm(-1) at 10 Hz, to 5.33 versus 2.88 mS cm(-1) at 1 MHz). We found no significant correlation between tumour size and measured electrical conductivity. While before ablation tumour tissue had considerably higher conductivity than normal tissue, the two had similar conductivity throughout the frequency range after ablation. Tumour tissue conductivity changed by +25% and -7% at 10 Hz and 1 MHz after ablation (0.23-0.29 at 10 Hz, and 0.43-0.40 at 1 MHz), while normal tissue conductivity increased by +270% and +10% at 10 Hz and 1 MHz (0.09-0.32 at 10 Hz and 0.37-0.41 at 1 MHz). These data can potentially be used to differentiate tumour from normal tissue diagnostically.

  12. Study of thermal and electrical parameters of workpieces during spray coating by electrolytic plasma jet

    International Nuclear Information System (INIS)

    Khafizov, A A; Shakirov, Yu I; Valiev, R A; Valiev, R I; Khafizova, G M

    2016-01-01

    In this paper the results are presented of thermal and electrical parameters of products in the system bottom layer - intermediate layer when applying protective coatings of ferromagnetic powder by plasma spray produced in an electric discharge with a liquid cathode, on steel samples. Temperature distribution and gradients in coating and intermediate coating were examined. Detailed descriptions of spray coating with ferromagnetic powder by plasma jet obtained in electrical discharge with liquid cathode and the apparatus for obtaining thereof is provided. Problem has been solved by using of Fourier analysis. Initial data for calculations is provided. Results of numerical analysis are provided as temporal functions of temperature in contiguity between coating and intermediate coating as well as temporal function of the value Q=q-φ; where q is density of heat current directed to the free surface of intermediate coating, φ is density of heat current in contiguity between coating and intermediate coating. The analysis of data given shows that in the systems of contact heat exchange bottom layer-intermediate layer with close values of the thermophysical characteristics of constituting materials is observed a slow increase of the temperature of the contact as a function of time. (paper)

  13. High-tension electrical-arc-induced thermal burns caused by railway overhead cables.

    Science.gov (United States)

    Koller, J

    1991-10-01

    Eleven patients with high-tension electrical-arc-induced thermal burns due to railway overhead cables were treated at the Bratislava Burn Department during a relatively short period of 18 months. All the injuries occurred by the same mechanism, that is persons climbing on top of railway carriages and approaching the 25,000 V a.c. overhead cables. All the burns were the result of an electrical arc passing externally to the body, with subsequent ignition of the victim's clothes. The cutaneous burns, ranging from 24 to 79 per cent of the BSA, were mostly deep partial to full skin thickness injuries. One patient died on day 5 postburn, the other survived. In spite of high-tension aetiology, no true electrical injuries appear to have occurred and no amputations were necessary. The pathophysiology and possible preventive measures are discussed. It must be stressed that arcing can be induced by an earthed object approaching, but not touching, a cable carrying a high voltage.

  14. Improvement in electrical, thermal and mechanical properties of epoxy by filling carbon nanotube

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available In this study, electrical, thermal and mechanical properties of multi-walled carbon nanotubes (CNTs reinforced Epon 862 epoxy have been evaluated. Firstly, 0.1, 0.2, 0.3, and 0.4 wt% CNT were infused into epoxy through a high intensity ultrasonic liquid processor and then mixed with EpiCure curing agent W using a high speed mechanical agitator. Electric conductivity, dynamic mechanical analysis (DMA, three point bending tests and fracture tests were then performed on unfilled, CNT-filled epoxy to identify the loading effect on the properties of materials. Experimental results show significant improvement in electric conductivity. The resistivity of epoxy decreased from 1014 Ω•m of neat epoxy to 10 Ω•m with 0.4% CNT. The experimental results also indicate that the frequency dependent behavior of CNT/epoxy nanocomposite can be modeled by R-C circuit, permittivity of material increase with increasing of CNT content. DMA studies revealed that filling the carbon nanotube into epoxy can produce a 90% enhancement in storage modulus and a 17°C increase in Tg. Mechanical test results showed that modulus increased with higher CNT loading percentages, but the 0.3 wt% CNT-infusion system showed the maximum strength and fracture toughness enhancement. The decrease in strength and fracture toughness in 0.4% CNT/epoxy was attributed to poor dispersions of nanotubes in the composite.

  15. Consideration on A.C. electric motor subjected to thermal and radiation accelerated ageing

    International Nuclear Information System (INIS)

    Doina, Segarceanu; Geambau, C.

    2001-01-01

    In the containment building of a nuclear reactor there are many types of equipment, such as motors, valve and transducers. Electric motors used in nuclear power stations operate under specific environmental conditions. These conditions are determinate by temperature, humidity, pressure, radiation and they may be normal conditions in service, or may be accident conditions occur during the postulated LOCA event. The testing of electric motors capability to meet and exceed the required performances under specific operating environmental conditions all along its operating life implies the performing of a sequence of tests in which the environmental conditions are simulated in a accelerated manner followed by accident simulation tests. Simulating the ageing position of the test sequence is more difficult because of the problem of extrapolating the results of short term accelerated laboratory experiments to the long term exposure (up to 30 years) that actually occur in a nuclear plant. Thermally induced ageing is the most frequently used ageing stress and also the most easily. The insulated system of a motor ageing under the influence of temperature and high - energy radiation can suffer important changes in its electro-insulating properties. Thus, by way of accelerated ageing motors are brought under conditions equivalent to those at the end of their service life, in a relatively short time. Accelerated ageing enables a shorting of electric motor performance evaluation time. (author)

  16. Study on thermal electric conversion system for FBR plant. Investigation for effective EVST waste heat recovery system

    International Nuclear Information System (INIS)

    Maekawa, Isamu; Kurata, Chikatoshi

    2004-02-01

    Recently, it has been important to reuse discharged heat energy from present nuclear plant, especially from sodium cooled FBR, which are typical high temperature system, in the view of reduction of environmental burden and improvement of heat efficiency for plant. The thermal electric conversion system can work only the temperature difference and has been applied to the limited fields such as space or military, however, that results show good merits for reliability, maintenance free, and so on. Recently, the development of new thermal electric conversion elements has made remarkable progress. In this study, for the effective utilization of waste heat from Monju', the prototype plant of FBR, we made an investigation of electric power generating system maintaining the cooling faculty by applying the thermal electric conversion system to sodium cooling line of EVST. Using the new type iron based thermal electric conversion elements, which are plentiful, economical and good for environmental harmonization, we have calculated the amount of heat exchange and power generation from sodium cooling line of EVST, and have investigated the module sizing, cost and subject to be settled. The results were , (1)The amount of power generation from sodium cooling line of EVST is smaller about one figure than motive power of sodium cooler fan. However, if Seebeck coefficient and heat conductivity of iron based thermal electric conversion elements shall be improved, power from sodium cooling line shall be able to cover the motive power. (2) The amount of heat released from sodium cooling line after the installation of thermal electric conversion module covers the necessity to maintain the sodium cooling faculty. (3) In case of the installation of module to the sodium cooler, it should be reconstructed because of tube arrangement modification. In case of the installation of module to the sodium connecting line, air ventilation system is needed to suppress the room temperature. (4) As

  17. Heat transfer and thermal management of electric vehicle batteries with phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Ramandi, M.Y.; Dincer, I.; Naterer, G.F. [University of Ontario Institute of Technology, Faculty of Engineering and Applied Science, Oshawa, ON (Canada)

    2011-07-15

    This paper examines a passive thermal management system for electric vehicle batteries, consisting of encapsulated phase change material (PCM) which melts during a process to absorb the heat generated by a battery. A new configuration for the thermal management system, using double series PCM shells, is analyzed with finite volume simulations. A combination of computational fluid dynamics (CFD) and second law analysis is used to evaluate and compare the new system against the single PCM shells. Using a finite volume method, heat transfer in the battery pack is examined and the results are used to analyse the exergy losses. The simulations provide design guidelines for the thermal management system to minimize the size and cost of the system. The thermal conductivity and melting temperature are studied as two important parameters in the configuration of the shells. Heat transfer from the surroundings to the PCM shell in a non-insulated case is found to be infeasible. For a single PCM system, the exergy efficiency is below 50%. For the second case for other combinations, the exergy efficiencies ranged from 30-40%. The second shell content did not have significant influence on the exergy efficiencies. The double PCM shell system showed higher exergy efficiencies than the single PCM shell system (except a case for type PCM-1). With respect to the reference environment, it is found that in all cases the exergy efficiencies decreased, when the dead-state temperatures rises, and the destroyed exergy content increases gradually. For the double shell systems for all dead-state temperatures, the efficiencies were very similar. Except for a dead-state temperature of 302 K, with the other temperatures, the exergy efficiencies for different combinations are well over 50%. The range of exergy efficiencies vary widely between 15 and 85% for a single shell system, and between 30-80% for double shell systems. (orig.)

  18. Heat transfer and thermal management of electric vehicle batteries with phase change materials

    Science.gov (United States)

    Ramandi, M. Y.; Dincer, I.; Naterer, G. F.

    2011-07-01

    This paper examines a passive thermal management system for electric vehicle batteries, consisting of encapsulated phase change material (PCM) which melts during a process to absorb the heat generated by a battery. A new configuration for the thermal management system, using double series PCM shells, is analyzed with finite volume simulations. A combination of computational fluid dynamics (CFD) and second law analysis is used to evaluate and compare the new system against the single PCM shells. Using a finite volume method, heat transfer in the battery pack is examined and the results are used to analyse the exergy losses. The simulations provide design guidelines for the thermal management system to minimize the size and cost of the system. The thermal conductivity and melting temperature are studied as two important parameters in the configuration of the shells. Heat transfer from the surroundings to the PCM shell in a non-insulated case is found to be infeasible. For a single PCM system, the exergy efficiency is below 50%. For the second case for other combinations, the exergy efficiencies ranged from 30-40%. The second shell content did not have significant influence on the exergy efficiencies. The double PCM shell system showed higher exergy efficiencies than the single PCM shell system (except a case for type PCM-1). With respect to the reference environment, it is found that in all cases the exergy efficiencies decreased, when the dead-state temperatures rises, and the destroyed exergy content increases gradually. For the double shell systems for all dead-state temperatures, the efficiencies were very similar. Except for a dead-state temperature of 302 K, with the other temperatures, the exergy efficiencies for different combinations are well over 50%. The range of exergy efficiencies vary widely between 15 and 85% for a single shell system, and between 30-80% for double shell systems.

  19. New constraints on the tectonic and thermal evolution of the Central-Western Carpathians

    Science.gov (United States)

    Castelluccio, Ada; Andreucci, Benedetta; Grigo, Domenico; Jankowski, Leszek; Ketcham, Richard A.; Mazzoli, Stefano; Szaniawski, Rafal; Zattin, Massimiliano

    2014-05-01

    The Central-Western Carpathians have been studied for long time but they are a still matter of discussion. In addition, they are one of the principal East European targets for oil and gas exploration. Understanding the tectonic evolution and the spatial and temporal variation of the thermal regime is crucial for this purpose. This orogene formed after the collision between the European Platform and the ALCAPA and Tisza-Dacia microplates from the Upper Jurassic to the Neogene. The widely accepted interpretation suggests the occurrence of the oceanic lithosphere subducting under the two microplates and the development of the oceanic suture in the Pieniny Klippen Belt area during the Paleocene. The subduction ends when the accretionary wedge reaches its present-day position on top of the southern border of the European Platform. The Carpathian arc can be subdivided into three tectonic domains: • Outer Carpathians made up of Upper Jurassic to Lower Miocene siliciclastic deposits intercalated with shales and sandstones; • Pieniny Klippen Belt formed by Mesozoic olistoliths and olistostromes in a sandy-clay Cretaceous sheared matrix; • Inner Carpathians consisting in Variscan allochthonous crystalline basement with its Mesozoic cover involved in the late Cretaceous folding and thrusting These deposits are unconformably overlain by the undeformed Central Carpathian Paleogene Basin successions. Cross-section balancing and sequential restoration integrated with low-temperature thermochronometry (apatite fission track and apatite (U-Th-Sm)/He analysis) can better constrain the tectonic evolution of this area and, in particular, its exhumation history. Seven balanced sections have been constructed across the Polish and Ukrainian Carpathians. The sequential restoration shows a thick-skinned tectonics during the Upper Cretaceous, involving the Inner Carpathian basin. The erosion of the Mesozoic basement cover and the sedimentation of these deposits in the foreland basin

  20. A Crewed Mission to Apophis Using a Hybrid Bimodal Nuclear Thermal Electric Propulsion (BNTEP) System

    Science.gov (United States)

    Mccurdy, David R.; Borowski, Stanley K.; Burke, Laura M.; Packard, Thomas W.

    2014-01-01

    A BNTEP system is a dual propellant, hybrid propulsion concept that utilizes Bimodal Nuclear Thermal Rocket (BNTR) propulsion during high thrust operations, providing 10's of kilo-Newtons of thrust per engine at a high specific impulse (Isp) of 900 s, and an Electric Propulsion (EP) system during low thrust operations at even higher Isp of around 3000 s. Electrical power for the EP system is provided by the BNTR engines in combination with a Brayton Power Conversion (BPC) closed loop system, which can provide electrical power on the order of 100's of kWe. High thrust BNTR operation uses liquid hydrogen (LH2) as reactor coolant propellant expelled out a nozzle, while low thrust EP uses high pressure xenon expelled by an electric grid. By utilizing an optimized combination of low and high thrust propulsion, significant mass savings over a conventional NTR vehicle can be realized. Low thrust mission events, such as midcourse corrections (MCC), tank settling burns, some reaction control system (RCS) burns, and even a small portion at the end of the departure burn can be performed with EP. Crewed and robotic deep space missions to a near Earth asteroid (NEA) are best suited for this hybrid propulsion approach. For these mission scenarios, the Earth return V is typically small enough that EP alone is sufficient. A crewed mission to the NEA Apophis in the year 2028 with an expendable BNTEP transfer vehicle is presented. Assembly operations, launch element masses, and other key characteristics of the vehicle are described. A comparison with a conventional NTR vehicle performing the same mission is also provided. Finally, reusability of the BNTEP transfer vehicle is explored.

  1. Proposals to enhance thermal efficiency programs and air pollution control in south-central Chile

    International Nuclear Information System (INIS)

    Schueftan, Alejandra; González, Alejandro D.

    2015-01-01

    Major cities in South-central Chile suffer high levels of particulate matter PM 10 and PM 2.5 due to combustion of solid fuels for heating. Exposure to these air pollutants is recognized as a major contribution to ill health in the region. Here we discuss new strategies to reduce air pollution. Regulations and subsidies focusing on improved combustion by providing drier wood fuel and better stoves have been in effect since 2007. However, air pollution due to combustion of wood fuel has been steadily rising, along with reports on health consequences. The paper analyzes a survey of 2025 households in the city of Valdivia, which found that wood fuel quality, stove renewal, and awareness of programs are strongly affected by income level, and that higher consumption of wood fuel is found in households already having better stoves and drier wood fuel. The analysis suggests that regulations intended to improve combustion are influenced by user's behavior and have limited potential for lowering pollution. We conclude that thermal refurbishment has a larger potential for improvement, not yet been implemented as an energy policy for the majority. Here we propose improvements and additions to current programs to enhance effectiveness and cover the whole social spectrum. - Highlights: • High levels of PM 2.5 from wood combustion affect cities of south-central Chile. • Current programs on dry wood fuel and stoves renewal have not reduced air pollution. • Real operation of wood stoves strongly depends on user's behavior. • Buildings' energy efficiency has greater potential for reducing emissions. • Retrofit prevents degradation of native forest and improves indoor temperature

  2. Brain potentials evoked by intraepidermal electrical stimuli reflect the central sensitization of nociceptive pathways.

    Science.gov (United States)

    Liang, M; Lee, M C; O'Neill, J; Dickenson, A H; Iannetti, G D

    2016-08-01

    Central sensitization (CS), the increased sensitivity of the central nervous system to somatosensory inputs, accounts for secondary hyperalgesia, a typical sign of several painful clinical conditions. Brain potentials elicited by mechanical punctate stimulation using flat-tip probes can provide neural correlates of CS, but their signal-to-noise ratio is limited by poor synchronization of the afferent nociceptive input. Additionally, mechanical punctate stimulation does not activate nociceptors exclusively. In contrast, low-intensity intraepidermal electrical stimulation (IES) allows selective activation of type II Aδ-mechano-heat nociceptors (II-AMHs) and elicits reproducible brain potentials. However, it is unclear whether hyperalgesia from IES occurs and coexists with secondary mechanical punctate hyperalgesia, and whether the magnitude of the electroencephalographic (EEG) responses evoked by IES within the hyperalgesic area is increased. To address these questions, we explored the modulation of the psychophysical and EEG responses to IES by intraepidermal injection of capsaicin in healthy human subjects. We obtained three main results. First, the intensity of the sensation elicited by IES was significantly increased in participants who developed robust mechanical punctate hyperalgesia after capsaicin injection (i.e., responders), indicating that hyperalgesia from IES coexists with punctate mechanical hyperalgesia. Second, the N2 peak magnitude of the EEG responses elicited by IES was significantly increased after the intraepidermal injection of capsaicin in responders only. Third, a receiver-operator characteristics analysis showed that the N2 peak amplitude is clearly predictive of the presence of CS. These findings suggest that the EEG responses elicited by IES reflect secondary hyperalgesia and therefore represent an objective correlate of CS. Copyright © 2016 the American Physiological Society.

  3. Site-specific Pt deposition and etching on electrically and thermally isolated SiO2 micro-disk surfaces

    International Nuclear Information System (INIS)

    Saraf, Laxmikant V

    2010-01-01

    Electrically and thermally isolated surfaces are crucial for improving the detection sensitivity of microelectronic sensors. The site-specific in situ growth of Pt nano-rods on thermally and electrically isolated SiO 2 micro-disks using wet chemical etching and a focused ion/electron dual beam (FIB-SEM) is demonstrated. Fabrication of an array of micro-cavities on top of a micro-disk is also demonstrated. The FIB source is utilized to fabricate through-holes in the micro-disks. Due to the amorphous nature of SiO 2 micro-disks, the Ga implantation possibly modifies through-hole sidewall surface chemistry rather than affecting its transport properties. Some sensor design concepts based on micro-fabrication of SiO 2 micro-disks utilizing thermally and electrically isolated surfaces are discussed from the viewpoint of applications in photonics and bio-sensing.

  4. An improved electrical and thermal model of a microbolometer for electronic circuit simulation

    Science.gov (United States)

    Würfel, D.; Vogt, H.

    2012-09-01

    The need for uncooled infrared focal plane arrays (IRFPA) for imaging systems has increased since the beginning of the nineties. Examples for the application of IRFPAs are thermography, pedestrian detection for automotives, fire fighting, and infrared spectroscopy. It is very important to have a correct electro-optical model for the simulation of the microbolometer during the development of the readout integrated circuit (ROIC) used for IRFPAs. The microbolometer as the sensing element absorbs infrared radiation which leads to a change of its temperature due to a very good thermal insulation. In conjunction with a high temperature coefficient of resistance (TCR) of the sensing material (typical vanadium oxide or amorphous silicon) this temperature change results in a change of the electrical resistance. During readout, electrical power is dissipated in the microbolometer, which increases the temperature continuously. The standard model for the electro-optical simulation of a microbolometer includes the radiation emitted by an observed blackbody, radiation emitted by the substrate, radiation emitted by the microbolometer itself to the surrounding, a heat loss through the legs which connect the microbolometer electrically and mechanically to the substrate, and the electrical power dissipation during readout of the microbolometer (Wood, 1997). The improved model presented in this paper takes a closer look on additional radiation effects in a real IR camera system, for example the radiation emitted by the casing and the lens. The proposed model will consider that some parts of the radiation that is reflected from the casing and the substrate is also absorbed by the microbolometer. Finally, the proposed model will include that some fraction of the radiation is transmitted through the microbolometer at first and then absorbed after the reflection at the surface of the substrate. Compared to the standard model temperature and resistance of the microbolometer can be

  5. Thermal modeling and parametric studies of a greenhouse fish pond in the Central Himalayan Region

    International Nuclear Information System (INIS)

    Sarkar, Bikash; Tiwari, G.N.

    2006-01-01

    This study describes the thermal modeling and its validation of greenhouse fish pond systems. Numerical computations have been performed for a typical day in the month of June, 2005, for the climatic condition of Champawat in the Central Himalayan Region. The energy balance equations have been written considering the effects of conduction, convection, radiation, evaporation and ventilation. The governing equations are numerically solved with Matlab 7.0 software to predict the water temperature. A parametric study has also been performed to find the effects of various parameters, namely the number of air changes per hour, the transmissivity (τ) and the isothermal mass and height of the greenhouse. It is observed that there is no significant effect in the parametric studies on water temperature due to the larger isothermal mass. The model has been validated with experimental data. On an average, the even span passive greenhouse fish pond can increase the inside temperature 4.14 deg. C higher than the temperature of an outdoor pond. Statistical analysis shows that the predicted and experimental values of water temperature exhibited fair agreement with a coefficient of correlation r = 0.90 and root mean square percent deviation e = 1.67%

  6. Study of Thermal Electrical Modified Etching for Glass and Its Application in Structure Etching

    Directory of Open Access Journals (Sweden)

    Zhan Zhan

    2017-02-01

    Full Text Available In this work, an accelerating etching method for glass named thermal electrical modified etching (TEM etching is investigated. Based on the identification of the effect in anodic bonding, a novel method for glass structure micromachining is proposed using TEM etching. To validate the method, TEM-etched glasses are prepared and their morphology is tested, revealing the feasibility of the new method for micro/nano structure micromachining. Furthermore, two kinds of edge effect in the TEM and etching processes are analyzed. Additionally, a parameter study of TEM etching involving transferred charge, applied pressure, and etching roughness is conducted to evaluate this method. The study shows that TEM etching is a promising manufacture method for glass with low process temperature, three-dimensional self-control ability, and low equipment requirement.

  7. Electrical transport properties of thermally evaporated phthalocyanine (H 2Pc) thin films

    Science.gov (United States)

    El-Nahass, M. M.; Farid, A. M.; Attia, A. A.; Ali, H. A. M.

    2006-08-01

    Thin films of H 2Pc of various thicknesses have been deposited onto glass substrates using thermal evaporation technique at room temperature. The dark electrical resistivity measurements were carried out at different temperatures in the range 298-473 K. An estimation of mean free path ( lo) of charge carriers in H 2Pc thin films was attempted. Measurements of thermoelectric power confirm that H 2Pc thin films behave as a p-type semiconductor. The current density-voltage characteristics of Au/H 2Pc/Au at room temperature showed ohmic conduction mechanism at low voltages. At higher voltages the space-charge-limited conduction (SCLC) accompanied by an exponential trap distribution was dominant. The temperature dependence of current density allows the determination of some essential parameters such as the hole mobility ( μh), the total trap concentration ( Nt), the characteristic temperature ( Tt) and the trap density P( E).

  8. Metal-dielectric interfaces in gigascale electronics thermal and electrical stability

    CERN Document Server

    He, Ming

    2012-01-01

    Metal-dielectric interfaces are ubiquitous in modern electronics. As advanced gigascale electronic devices continue to shrink, the stability of these interfaces is becoming an increasingly important issue that has a profound impact on the operational reliability of these devices. In this book, the authors present the basic science underlying  the thermal and electrical stability of metal-dielectric interfaces and its relationship to the operation of advanced interconnect systems in gigascale electronics. Interface phenomena, including chemical reactions between metals and dielectrics, metallic-atom diffusion, and ion drift, are discussed based on fundamental physical and chemical principles. Schematic diagrams are provided throughout the book to illustrate  interface phenomena and the principles that govern them. Metal-Dielectric Interfaces in Gigascale Electronics  provides a unifying approach to the diverse and sometimes contradictory test results that are reported in the literature on metal-dielectric i...

  9. Hydroxylated graphene-based flexible carbon film with ultrahigh electrical and thermal conductivity.

    Science.gov (United States)

    Ding, Jiheng; Ur Rahman, Obaid; Zhao, Hongran; Peng, Wanjun; Dou, Huimin; Chen, Hao; Yu, Haibin

    2017-09-29

    Graphene-based films are widely used in the electronics industry. Here, surface hydroxylated graphene sheets (HGS) have been synthesized from natural graphite (NG) by a rapid and efficient molten hydroxide-assisted exfoliation technique. This method enables preparation of aqueous dispersible graphene sheets with a high dispersed concentration (∼10.0 mg ml -1 ) and an extraordinary production yield (∼100%). The HGS dispersion was processed into graphene flexible film (HGCF) through fast filtration, annealing treatment and mechanical compression. The HGS endows graphene flexible film with a high electrical conductivity of 11.5 × 10 4 S m -1 and a superior thermal conductivity of 1842 W m -1 K -1 . Simultaneously, the superflexible HGCF could endure 3000 repeated cycles of bending or folding. As a result, this graphene flexible film is expected to be integrated into electronic packaging and high-power electronics applications.

  10. Electrical and thermal transport in the quasiatomic limit of coupled Luttinger liquids

    Science.gov (United States)

    Szasz, Aaron; Ilan, Roni; Moore, Joel E.

    2017-02-01

    We introduce a new model for quasi-one-dimensional materials, motivated by intriguing but not yet well-understood experiments that have shown two-dimensional polymer films to be promising materials for thermoelectric devices. We consider a two-dimensional material consisting of many one-dimensional systems, each treated as a Luttinger liquid, with weak (incoherent) coupling between them. This approximation of strong interactions within each one-dimensional chain and weak coupling between them is the "quasiatomic limit." We find integral expressions for the (interchain) transport coefficients, including the electrical and thermal conductivities and the thermopower, and we extract their power law dependencies on temperature. Luttinger liquid physics is manifested in a violation of the Wiedemann-Franz law; the Lorenz number is larger than the Fermi liquid value by a factor between γ2 and γ4, where γ ≥1 is a measure of the electron-electron interaction strength in the system.

  11. Mechanical, Thermal, and Electrical Properties of Graphene-Epoxy Nanocomposites—A Review

    Directory of Open Access Journals (Sweden)

    Rasheed Atif

    2016-08-01

    Full Text Available Monolithic epoxy, because of its brittleness, cannot prevent crack propagation and is vulnerable to fracture. However, it is well established that when reinforced—especially by nano-fillers, such as metallic oxides, clays, carbon nanotubes, and other carbonaceous materials—its ability to withstand crack propagation is propitiously improved. Among various nano-fillers, graphene has recently been employed as reinforcement in epoxy to enhance the fracture related properties of the produced epoxy–graphene nanocomposites. In this review, mechanical, thermal, and electrical properties of graphene reinforced epoxy nanocomposites will be correlated with the topographical features, morphology, weight fraction, dispersion state, and surface functionalization of graphene. The factors in which contrasting results were reported in the literature are highlighted, such as the influence of graphene on the mechanical properties of epoxy nanocomposites. Furthermore, the challenges to achieving the desired performance of polymer nanocomposites are also suggested throughout the article.

  12. Electrical, thermal and magnetic behaviour of the metallic glass Fe80B20 in the crystallization process

    International Nuclear Information System (INIS)

    Isalgue, A.; Cusido, J.A.

    1986-01-01

    The thermal, electrical DC conductivity and magnetic properties have been studied in the crystallization process of the metallic glass Fe 80 B 20 (Metglass 2605) induced by heat treatment. The electrical and thermal conductivity, the coercive force and the remanence are strongly affected with the crystallization of the glass. Two steps can be dicerned from the magnetic measurements; the differences between the two steps are interpreted in the basis of the ''spherulite-type'', grown of Fe 3 B in the first crystallization step and the aparition of Fe 2 B in the second step. (author)

  13. Human factors research in Central Research Institute of Electric Power Industry creation of safety culture

    International Nuclear Information System (INIS)

    Horie, Yasuo

    2002-01-01

    To prevent accident of nuclear power plant, Human Factors Center was built in the Central Research Institute of Electric Power Industry in July 1987. It developed an evaluation method of human error cases and an application method of human factors information. Now it continues analysis and application of human factors information, development of training/work support tools and research/experiment of human behavior. Japan-Human Performance Evaluation System (J-HPES) was developed as an analytical system for analysis and evaluation of human factors related to the trouble and for using the result as the common property by storage the analytical results. J-HPES has a standard procedure consisted of collecting and analyzing data and proposing the countermeasures. The analytical results are arranged by 4 kinds of charts by putting into the form of a diagram. Moreover, it tries to find the causes with indirect and potential causes. Two kinds of materials, Caution Report and Human Factors Precept by means of Illustrations, are published. People can gain access to HFC database by URL http://criepi.denken.or.jp/CRIEPI/HFC/DB. To prevent these accidents, creation of human factors culture has been required. Five kinds of teaching materials and the training method are developed. (S.Y.)

  14. Sustainable electricity transitions in Germany in a spatial context: between localism and centralism

    Directory of Open Access Journals (Sweden)

    Gerhard Fuchs

    2014-01-01

    Full Text Available While the traditional form of electricity generation and supply is based on centralized structures with large-scale power plants, the objective of a strongly decentralized form of energy supply is increasingly becoming important. Sustainability-oriented energy transitions are relying on various sorts of renewable energies coupled with energy-efficiency initiatives. In the current existing regulatory and market frameworks in Germany and elsewhere, important technical and institutional innovations for energy transitions were and are being developed, tested, and brought to application on regional and local levels. Regions, cities, and villages experimenting with socio-technical innovations and aiming to implement new concepts have to develop governance structures under high uncertainty. These governance structures mirror space-specific social, political, technological and economic constellations. The present article introduces an analytical approach for studying emergent forms of governance and uses four cases from Germany to apply the approach. Research is based on a comparative case study research design, using primarily expert interviews and document analyses as data sources. The cases demonstrate that sustainable energy transitions are driven forward by a host of different actors with different aims and interests, culminating in the development of space-specific technological mixes and situative governance structures. Sustainable energy transitions neither follow a master plan, nor are they coordinated on a national level. The upper political levels and external events pose severe constraints for the implementation of local transition initiatives. Future research should aim to highlight and analyze the contentious character of energy transitions.

  15. NDT developments in the CEGB [Central Electricity Generating Board] for turbine and generator rotor shafts

    International Nuclear Information System (INIS)

    Denby, D.

    1990-01-01

    In common with many utilities world-wide, the Central Electricity Generating Board (CEGB) has suffered problems of cracking in turbine and generator rotors, in a wide range of Units. The type of cracking that has stimulated most NDT development work is transverse cracking initiating at the outside of shafts, though axial cracking at turbine disc keyways has also required considerable effort. This paper describes current and recent developments of NDT techniques and equipment designed to provide early warning and assessment of service-induced cracks which could propagate to failure. The following developments are included: in-situ inspection of LP turbine rotor shafts by means of low-angle ultrasonic beams fired along the length of the shaft; techniques for detecting and measuring cracking in shrunk-on turbine disc keyways; a remote, in-situ technique for cracking initiating in the pole teeth of large generator rotors, aimed at detecting cracks while they are small enough for the rotor to be repaired; an in-situ technique for rapidly inspecting these same generator rotors for the presence of larger cracks, by an ultrasonic beam fired along the length of the shaft; ultrasonic in-situ inspection of generator rotor teeth directly under the shrunk-on end (retaining) rings

  16. Fluid power network for centralized electricity generation in offshore wind farms

    International Nuclear Information System (INIS)

    Jarquin-Laguna, A

    2014-01-01

    An innovative and completely different wind-energy conversion system is studied where a centralized electricity generation within a wind farm is proposed by means of a hydraulic network. This paper presents the dynamic interaction of two turbines when they are coupled to the same hydraulic network. Due to the stochastic nature of the wind and wake interaction effects between turbines, the operating parameters (i.e. pitch angle, rotor speed) of each turbine are different. Time domain simulations, including the main turbine dynamics and laminar transient flow in pipelines, are used to evaluate the efficiency and rotor speed stability of the hydraulic system. It is shown that a passive control of the rotor speed, as proposed in previous work for a single hydraulic turbine, has strong limitations in terms of performance for more than one turbine coupled to the same hydraulic network. It is concluded that in order to connect several turbines, a passive control strategy of the rotor speed is not sufficient and a hydraulic network with constant pressure is suggested. However, a constant pressure network requires the addition of active control at the hydraulic motors and spear valves, increasing the complexity of the initial concept. Further work needs to be done to incorporate an active control strategy and evaluate the feasibility of the constant pressure hydraulic network

  17. Electrical, thermal and electrochemical properties of disordered carbon prepared from palygorskite and cane molasses

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Edelio Danguillecourt, E-mail: edelioalvarez42@gmail.com [Instituto Superior Minero Metalúrgico (ISMM), Moa 83300 (Cuba); Laffita, Yodalgis Mosqueda, E-mail: yodalgis@imre.uh.cu [Institute of Materials Science and Technology-Havana University, La Habana 10400 (Cuba); Montoro, Luciano Andrey, E-mail: landrey.montoro@gmail.com [Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 31270-901 (Brazil); Della Santina Mohallem, Nelcy, E-mail: nelcydsm@gmail.com [Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais 31270-901 (Brazil); Cabrera, Humberto, E-mail: hcabrera@ictp.it [SPIE-ICTP Anchor Research in Optics Program Laboratory, International Centre for Theoretical Physics (ICTP), Strada Costiera 11, Trieste 34151 (Italy); Centro Multidisciplinario de Ciencias, Instituto Venezolano de Investigaciones Científicas (IVIC), 5101 Mérida (Venezuela, Bolivarian Republic of); Pérez, Guillermo Mesa, E-mail: guille@ceaden.edu.cu [National Center for Technological Research (CEADEN), La Habana 10400 (Cuba); Frutis, Miguel Aguilar, E-mail: mafrutis@yahoo.es [CICATA-IPN, Legaria 694, Col. Irrigacion, Del., Miguel Hidalgo CP 11500 (Mexico); Cappe, Eduardo Pérez, E-mail: cappe@imre.uh.cu [Institute of Materials Science and Technology-Havana University, La Habana 10400 (Cuba)

    2017-02-15

    We have synthesized and electrochemically tested a carbon sample that was suitable as anode for lithium secondary battery. The synthesis was based on the use of the palygorskite clay as template and sugar cane molasses as carbon source. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Brunauer–Emmett–Teller (BET) measurements and High Resolution Transmission Electron Microscope (HRTEM) analysis showed that the nanometric carbon material has a highly disordered graphene-like wrinkled structure and large specific surface area (467 m{sup 2} g{sup −1}). The compositional characterization revealed a 14% of heteroatoms-containing groups (O, H, N, S) doping the as-prepared carbon. Thermophysical measurements revealed the good thermal stability and an acceptable thermal diffusivity (9·10{sup −7} m{sup 2} s{sup −1}) and conductivity (1.1 W m{sup −1} K{sup −1}) of this carbon. The electrical properties showed an electronic conductivity of hole-like carriers of approximately one S/cm in a 173–293 K range. The testing of this material as anodes in a secondary lithium battery displayed a high specific capacity and excellent performance in terms of number of cycles. A high reversible capacity of 356 mA h g{sup −1} was reached. - Graphical abstract: TEM image and electrochemistry behavior of a new graphene oxide-like carbon. - Highlights: • A high disordered graphene oxide-like conducting carbon is reported. • The synthesis was based on palygorskite and sugar cane molasses as precursors. • The disordered conducting carbon is composed of doped- graphene heterogeneous domains. • This material combines a large specific surface area and high electric conductivity. • The thermophysical and electrochemical properties of this material reveal adequate behavior.

  18. Synthesis and characterization of oligobenzimidazoles: Electrochemical, electrical, optical, thermal and rectification properties

    Science.gov (United States)

    Anand, Siddeswaran; Muthusamy, Athianna

    2018-03-01

    A series of benzimidazole monomers, (2-(2, 4-dihydroxyphenyl)-1H-benzimidazol-5-yl)(phenyl) methanone (BIKH), 2-(3-ethoxy-2-hydroxyphenyl)-1H-benzo [d]imidazole-5-yl) (phenyl) methanone (BIKE) and 2-(5-bromo-2-hydroxyphenyl)-1H-benzo [d]imidazole-5-yl) (phenyl) methanone (BIKB) were prepared by condensing three substituted aromatic aldehydes with 3, 4-diaminobenzophenone. In aqueous alkaline medium the benzimidazoles were converted in to oligomers by oxidative polycondensation using NaOCl as oxidant. The formation of monomers and oligomers were confirmed with 1H, 13C NMR, FT-IR, and UV-visible spectroscopic techniques. The oligomers were investigated for their optical, electrical, electrochemical and thermal properties. The electrochemical and optical band gaps of monomers and oligomers were calculated using both UV-visible spectroscopy and cyclic voltametry respectively. The band gap values of monomers are compared with band gap values obtained from quantum theoretical calculations with DFT. The electrical conductivity studies of iodine doped and undoped oligomers were done using two point probe technique. It is found that these values are showing good correlation with the charge densities on imidazole nitrogen obtained from Huckel method. The conductivity of oligomers increases with increase in iodine vapour contact time. The dielectric properties of oligomers have been investigated at different temperature and frequency. The dielectric measurement data were used to calculate the AC conductivity and activation energy of oligomers. Oligomer OBIKH is having greater thermal stability due to its number of chain propagation sites than other oligomers and is shown by its high carbines residue of around 60% at 600 °C in thermogravimetric analysis. I-V characteristics of oligobenzimidazole p-n diodes have shown good rectifying nature in the range -4 to 4 V.

  19. Electrical, thermal and electrochemical properties of disordered carbon prepared from palygorskite and cane molasses

    International Nuclear Information System (INIS)

    Alvarez, Edelio Danguillecourt; Laffita, Yodalgis Mosqueda; Montoro, Luciano Andrey; Della Santina Mohallem, Nelcy; Cabrera, Humberto; Pérez, Guillermo Mesa; Frutis, Miguel Aguilar; Cappe, Eduardo Pérez

    2017-01-01

    We have synthesized and electrochemically tested a carbon sample that was suitable as anode for lithium secondary battery. The synthesis was based on the use of the palygorskite clay as template and sugar cane molasses as carbon source. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Brunauer–Emmett–Teller (BET) measurements and High Resolution Transmission Electron Microscope (HRTEM) analysis showed that the nanometric carbon material has a highly disordered graphene-like wrinkled structure and large specific surface area (467 m 2 g −1 ). The compositional characterization revealed a 14% of heteroatoms-containing groups (O, H, N, S) doping the as-prepared carbon. Thermophysical measurements revealed the good thermal stability and an acceptable thermal diffusivity (9·10 −7 m 2 s −1 ) and conductivity (1.1 W m −1 K −1 ) of this carbon. The electrical properties showed an electronic conductivity of hole-like carriers of approximately one S/cm in a 173–293 K range. The testing of this material as anodes in a secondary lithium battery displayed a high specific capacity and excellent performance in terms of number of cycles. A high reversible capacity of 356 mA h g −1 was reached. - Graphical abstract: TEM image and electrochemistry behavior of a new graphene oxide-like carbon. - Highlights: • A high disordered graphene oxide-like conducting carbon is reported. • The synthesis was based on palygorskite and sugar cane molasses as precursors. • The disordered conducting carbon is composed of doped- graphene heterogeneous domains. • This material combines a large specific surface area and high electric conductivity. • The thermophysical and electrochemical properties of this material reveal adequate behavior.

  20. Experience of Implementing a Distributed Control System for Thermal and Mechanical and Electrical Equipment at the South-West CHP

    Energy Technology Data Exchange (ETDEWEB)

    Babkin, K. V., E-mail: babkin@uztec.ru; Tsvetkov, M. S.; Kostyuk, R. I.; Chugin, A. V. [SC “South-West CHP” (Russian Federation); Bilenko, V. A.; Molchanov, K. A.; Fedunov, V. V. [JSC “Interautomatika” (Russian Federation)

    2015-01-15

    Results of implementing an SPPA-T3000-based unified distributed control system for thermal and mechanical and electrical equipment at the South-West CHP are discussed. Hardware solutions for integration with local control systems, control of electrical equipment in compliance with the standards IEC 61850, Modbus RTU, and communication between the plant control system and the System Operator of the Unified Power System are described.

  1. Experience of Implementing a Distributed Control System for Thermal and Mechanical and Electrical Equipment at the South-West CHP

    International Nuclear Information System (INIS)

    Babkin, K. V.; Tsvetkov, M. S.; Kostyuk, R. I.; Chugin, A. V.; Bilenko, V. A.; Molchanov, K. A.; Fedunov, V. V.

    2015-01-01

    Results of implementing an SPPA-T3000-based unified distributed control system for thermal and mechanical and electrical equipment at the South-West CHP are discussed. Hardware solutions for integration with local control systems, control of electrical equipment in compliance with the standards IEC 61850, Modbus RTU, and communication between the plant control system and the System Operator of the Unified Power System are described

  2. Improving the engineering-and-economical performance of ore-thermal electric furnaces in the smelting of silicomanganese

    Science.gov (United States)

    Kondrashov, V. P.; Pogrebisskiy, M. Ya; Lykov, A. G.; Rabinovich, V. L.; Bulgakov, A. S.

    2018-02-01

    Ways of increase of ore-heating electric furnaces, used for production of silicomanganese, engineering-and-economical performance are analyzed. Questions of data of the electric, thermal and technological modes of the furnace functioning collecting and processing for use in operation of an advanced control system of the furnace providing increase in technical and economic efficiency of technological process and an adaptability to quality of burden stock are considered.

  3. Computational modelling of internally cooled wet (ICW) electrodes for radiofrequency ablation: impact of rehydration, thermal convection and electrical conductivity.

    Science.gov (United States)

    Trujillo, Macarena; Bon, Jose; Berjano, Enrique

    2017-09-01

    (1) To analyse rehydration, thermal convection and increased electrical conductivity as the three phenomena which distinguish the performance of internally cooled electrodes (IC) and internally cooled wet (ICW) electrodes during radiofrequency ablation (RFA), (2) Implement a RFA computer model with an ICW which includes these phenomena and (3) Assess their relative influence on the thermal and electrical tissue response and on the coagulation zone size. A 12-min RFA in liver was modelled using an ICW electrode (17 G, 3 cm tip) by an impedance-control pulsing protocol with a constant current of 1.5 A. A model of an IC electrode was used to compare the ICW electrode performance and the computational results with the experimental results. Rehydration and increased electrical conductivity were responsible for an increase in coagulation zone size and a delay (or absence) in the occurrence of abrupt increases in electrical impedance (roll-off). While the increased electrical conductivity had a remarkable effect on enlarging the coagulation zone (an increase of 0.74 cm for differences in electrical conductivity of 0.31 S/m), rehydration considerably affected the delay in roll-off, which, in fact, was absent with a sufficiently high rehydration level. In contrast, thermal convection had an insignificant effect for the flow rates considered (0.05 and 1 mL/min). Computer results suggest that rehydration and increased electrical conductivity were mainly responsible for the absence of roll-off and increased size of the coagulation zone, respectively, and in combination allow the thermal and electrical performance of ICW electrodes to be modelled during RFA.

  4. Study of light-absorbing crystal birefringence and electrical modulation mechanisms for coupled thermal-optical effects.

    Science.gov (United States)

    Zhou, Ji; He, Zhihong; Ma, Yu; Dong, Shikui

    2014-09-20

    This paper discusses Gaussian laser transmission in double-refraction crystal whose incident light wavelength is within its absorption wave band. Two scenarios for coupled radiation and heat conduction are considered: one is provided with an applied external electric field, the other is not. A circular heat source with a Gaussian energy distribution is introduced to present the crystal's light-absorption process. The electromagnetic field frequency domain analysis equation and energy equation are solved to simulate the phenomenon by using the finite element method. It focuses on the influence of different values such as wavelength, incident light intensity, heat transfer coefficient, ambient temperature, crystal thickness, and applied electric field strength. The results show that the refraction index of polarized light increases with the increase of crystal temperature. It decreases as the strength of the applied electric field increases if it is positive. The mechanism of electrical modulation for the thermo-optical effect is used to keep the polarized light's index of refraction constant in our simulation. The quantitative relation between thermal boundary condition and strength of applied electric field during electrical modulation is determined. Numerical results indicate a possible approach to removing adverse thermal effects such as depolarization and wavefront distortion, which are caused by thermal deposition during linear laser absorption.

  5. Electrical, thermal and electrochemical properties of disordered carbon prepared from palygorskite and cane molasses

    Science.gov (United States)

    Alvarez, Edelio Danguillecourt; Laffita, Yodalgis Mosqueda; Montoro, Luciano Andrey; Della Santina Mohallem, Nelcy; Cabrera, Humberto; Pérez, Guillermo Mesa; Frutis, Miguel Aguilar; Cappe, Eduardo Pérez

    2017-02-01

    We have synthesized and electrochemically tested a carbon sample that was suitable as anode for lithium secondary battery. The synthesis was based on the use of the palygorskite clay as template and sugar cane molasses as carbon source. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Brunauer-Emmett-Teller (BET) measurements and High Resolution Transmission Electron Microscope (HRTEM) analysis showed that the nanometric carbon material has a highly disordered graphene-like wrinkled structure and large specific surface area (467 m2 g-1). The compositional characterization revealed a 14% of heteroatoms-containing groups (O, H, N, S) doping the as-prepared carbon. Thermophysical measurements revealed the good thermal stability and an acceptable thermal diffusivity (9·10-7 m2 s-1) and conductivity (1.1 W m-1 K-1) of this carbon. The electrical properties showed an electronic conductivity of hole-like carriers of approximately one S/cm in a 173-293 K range. The testing of this material as anodes in a secondary lithium battery displayed a high specific capacity and excellent performance in terms of number of cycles. A high reversible capacity of 356 mA h g-1 was reached.

  6. Thermal characterisation of compact heat exchangers for air heating and cooling in electric vehicles

    International Nuclear Information System (INIS)

    Torregrosa-Jaime, B.; Corberán, J.M.; Payá, J.; Delamarche, J.L.

    2017-01-01

    The use of air conditioning in all-electric cars reduces their driving range by 33% in average. With the purpose of reducing the energy consumption of the vehicle and optimising the performance of the batteries, the mobile air-conditioning can be integrated with the temperature control system of the powertrain by means of a coolant loop. In such layouts, the air-to-coolant heat exchangers must operate efficiently in both air heating and cooling modes. Dynamic simulation tools comprising the entire thermal system are essential to assess its performance. In this context, fast but accurate models of the system components are required. This paper presents the thermal characterisation of a commercial compact louvered-fin flat-tube heat exchanger (heater core) for this novel application, based on an experimental campaign comprising 279 working points that reflect real air-conditioning (heating and cooling) working conditions. A general methodology to fit a single correlation of the global heat transfer coefficient for both dry and wet working conditions is explained. The semiempirical correlation developed is employed in a single-node model of the heat exchanger that requires minimal computation time. The present model predicts the heat transfer rate with an average deviation of 3.5% in the cases with dehumidification and 1.9% in the cases when the heat exchanger remains dry.

  7. High temperature thermal conductivity measurements of UO2 by Direct Electrical Heating. Final report

    International Nuclear Information System (INIS)

    Bassett, B.

    1980-10-01

    High temperature properties of reactor type UO 2 pellets were measured using a Direct Electrical Heating (DEH) Facility. Modifications to the experimental apparatus have been made so that successful and reproducible DEH runs may be carried out while protecting the pellets from oxidation at high temperature. X-ray diffraction measurements on the UO 2 pellets have been made before and after runs to assure that sample oxidation has not occurred. A computer code has been developed that will model the experiment using equations that describe physical properties of the material. This code allows these equations to be checked by comparing the model results to collected data. The thermal conductivity equation for UO 2 proposed by Weilbacher has been used for this analysis. By adjusting the empirical parameters in Weilbacher's equation, experimental data can be matched by the code. From the several runs analyzed, the resulting thermal conductivity equation is lambda = 1/4.79 + 0.0247T/ + 1.06 x 10 -3 exp[-1.62/kT/] - 4410. exp[-3.71/kT/] where lambda is in w/cm K, k is the Boltzman constant, and T is the temperature in Kelvin

  8. Experimental Investigation of Surface Layer Properties of High Thermal Conductivity Tool Steel after Electrical Discharge Machining

    Directory of Open Access Journals (Sweden)

    Rafał Świercz

    2017-12-01

    Full Text Available New materials require the use of advanced technology in manufacturing complex shape parts. One of the modern materials widely used in the tool industry for injection molds or hot stamping dies is high conductivity tool steel (HTCS 150. Due to its hardness (55 HRC and thermal conductivity at 66 W/mK, this material is difficult to machine by conventional treatment and is being increasingly manufactured by nonconventional technology such as electrical discharge machining (EDM. In the EDM process, material is removed from the workpiece by a series of electrical discharges that cause changes to the surface layers properties. The final state of the surface layer directly influences the durability of the produced elements. This paper presents the influence of EDM process parameters: discharge current Ic and the pulse time ton on surface layer properties. The experimental investigation was carried out with an experimental methodology design. Surface layers properties including roughness 3D parameters, the thickness of the white layer, heat affected zone, tempered layer and occurring micro cracks were investigated and described. The influence of the response surface methodology (RSM of discharge current Ic and the pulse time ton on the thickness of the white layer and roughness parameters Sa, Sds and Ssc were described and established.

  9. Feasibility study of Thermal Electric Generator Configurations as Renewable Energy Sources

    Science.gov (United States)

    Akmal Johar, Muhammad; Yahaya, Zulkarnain; Faizan Marwah, Omar Mohd; Jamaludin, Wan Akashah Wan; Najib Ribuan, Mohamed

    2017-10-01

    Thermoelectric Generator is a solid state device that able to convert thermal energy into electrical energy via temperature differences. The technology is based on Seebeck effect that was discovered in year 1821, however till now there is no real application to exploit this capability in mass scale. This research will report the performance analysis of TEG module in controlled environment of lab scale model. National Instrument equipment and Labview software has been choosen and developed to measure the TEG module in various configurations. Based on the experiment result, an additional passive cooling effort has produced a better ΔT by 7°C. The optimal electrical loading of single TEG is recorded at 200Ω. As for circuit connections, series connection has shown superior power output when compared to parallel connection or single TEG. A series connection of two TEGs has produced power output of 416.82μW when compared to other type connections that only produced around 100μW.

  10. Effects of high intensity pulsed electric field and thermal treatments on a lipase from Pseudomonas fluorescens.

    Science.gov (United States)

    Bendicho, S; Estela, C; Giner, J; Barbosa-Cánovas, G V; Martin, O

    2002-01-01

    Milk and dairy products may contain microorganisms capable of secreting lipases that cause sensory defects and technological problems in the dairy industry. In this study, the effects of thermal and high-intensity pulsed electric field (HIPEF) treatments on an extracellular lipase from Pseudomonas fluorescens, suspended in a simulated skim milk ultrafiltrate (SMUF) have been evaluated. Heat treatments applied were up to 30 min from 50 to 90 degrees C. HIPEF treatments were carried out using pilot plant facilities in a batch or continuous flow mode, where treatment chambers consisted of parallel and coaxial configuration, respectively. Samples were subjected to up to 80 pulses at electric field intensities ranging from 16.4 to 37.3 kV/cm. This resulted in a lipase that was quite resistant to heat and also to HIPEF. High (75 degrees C-15 s) and low pasteurization treatments (63 degrees C-30 min) led to inactivations of 5 and 20%, respectively. Using the batch-mode HIPEF equipment, a 62.1% maximum activity depletion was achieved after 80 pulses at 27.4 kV/cm. However, when HIPEF treatments were applied in the continuous flow mode, an inactivation rate of just 13% was achieved, after applying 80 pulses at 37.3 kV/cm and 3.5 Hz. The results of both heat and HIPEF treatments on enzyme inactivation were adjusted with good agreement to a first-order kinetic model (R2 > 62.3%).

  11. Effects of cation substitution on thermal expansion and electrical properties of lanthanum chromites

    International Nuclear Information System (INIS)

    Ding Xifeng; Liu Yingjia; Gao Ling; Guo Lucun

    2006-01-01

    The effects of cation substitution on the sintering characteristics, thermal expansion and electrical conductivity properties of La(AE)Cr(M)O 3 (AE=Mg, Ca, Sr, M=Ni, Cu, Co) were investigated. The sinterability of alkaline metal earth (AE)-doped LaCrO 3 increased with AE contents in a sequence of Ca > Sr > Mg. Sr-doped LaCrO 3 sample had a TEC compatible with that of 8YSZ electrolyte. The transition metals of Ni, Co and Cu substituted in Cr-site further optimized the sinterability of La 0.85 Sr 0.15 CrO 3 in air. Ni and Co could effectively enhance the electrical conductivity from room temperature to 1123 K though the concomitant increase in TEC was distinctively large with Co doping. The TEC was controlled by co-doping Ni and Co in Cr-site, and La 0.85 Sr 0.15 Cr 0.95 Ni 0.02 Co 0.02 O 3 exhibited a TEC of 10.9 x 10 -6 /K, which was matched with that of 8YSZ, indicating that it could be suitable to be used as an SOFC interconnect material

  12. Electrical Conductivity of Rocks and Dominant Charge Carriers. Part 1; Thermally Activated Positive Holes

    Science.gov (United States)

    Freund, Friedemann T.; Freund, Minoru M.

    2012-01-01

    The prevailing view in the geophysics community is that the electrical conductivity structure of the Earth's continental crust over the 5-35 km depth range can best be understood by assuming the presence of intergranular fluids and/or of intragranular carbon films. Based on single crystal studies of melt-grown MgO, magma-derived sanidine and anorthosite feldspars and upper mantle olivine, we present evidence for the presence of electronic charge carriers, which derive from peroxy defects that are introduced during cooling, under non-equilibrium conditions, through a redox conversion of pairs of solute hydroxyl arising from dissolution of H2O.The peroxy defects become thermally activated in a 2-step process, leading to the release of defect electrons in the oxygen anion sublattice. Known as positive holes and symbolized by h(dot), these electronic charge carriers are highly mobile. Chemically equivalent to O(-) in a matrix of O(2-) they are highly oxidizing. Being metastable they can exist in the matrix of minerals, which crystallized in highly reduced environments. The h(dot) are highly mobile. They appear to control the electrical conductivity of crustal rocks in much of the 5-35 km depth range.

  13. Mechanical and Thermal Properties of Pulsed Electric Current Sintered (PECS) Cu-Diamond Compacts

    Science.gov (United States)

    Ritasalo, Riina; Kanerva, Ulla; Ge, Yanling; Hannula, Simo-Pekka

    2014-04-01

    In this work, dispersion strengthening of copper by diamonds is explored. In particular, the influence of 50- and 250-nm diamonds at contents of 3 and 6 vol. pct on the mechanical and thermal properties of pulsed electric current sintered (PECS) Cu composites is studied. The composite powders were prepared by mechanical alloying in argon atmosphere using a high-energy vibratory ball mill. The PECS compacts prepared had high density (>97 pct of T.D.) with quite evenly distributed diamonds. The effectiveness of dispersoids in increasing the microhardness was more pronounced at a smaller particle size and larger volume fraction, explained by Hall-Petch and Orowan strengthening models. The microhardness of Cu with 6 and 3 vol. pct nanodiamonds and pure sm-Cu (submicron-sized Cu) was 1.77, 1.46, and 1.02 GPa, respectively. In annealing experiments at 623 K to 873 K (350 °C to 600 °C), the composites with 6 vol. pct dispersoids retained their hardness better than those with less dispersoids or sm-Cu. The coefficient of thermal expansion was lowered when diamonds were added, being the lowest at about 14 × 10-6 K-1 between 473 K and 573 K (200 °C and 300 °C). Good bonding between the copper and diamond was qualitatively demonstrated by nanoindentation. In conclusion, high-quality Cu-diamond composites can be produced by PECS with improved strength and better thermal stability than for sm-Cu.

  14. A model for the scattering of high-frequency electromagnetic fields from dielectrics exhibiting thermally-activated electrical losses

    Science.gov (United States)

    Hann, Raiford E.

    1991-01-01

    An equivalent circuit model (ECM) approach is used to predict the scattering behavior of temperature-activated, electrically lossy dielectric layers. The total electrical response of the dielectric (relaxation + conductive) is given by the ECM and used in combination with transmission line theory to compute reflectance spectra for a Dallenbach layer configuration. The effects of thermally-activated relaxation processes on the scattering properties is discussed. Also, the effect of relaxation and conduction activation energy on the electrical properties of the dielectric is described.

  15. A Study of Demand Response Effect of Thermal Storage Air-Conditioning Systems in Consideration of Electricity Market Prices

    Science.gov (United States)

    Omagari, Yuko; Sugihara, Hideharu; Tsuji, Kiichiro

    This paper evaluates the economic impact of the introduction of customer-owned Thermal Storage Air-conditioning (TSA) systems, in an electricity market, from the viewpoint of the load service entity. We perform simulations on the condition that several thousand customers install TSA systems and shift peak demand in an electricity market by one percent. Our numerical results indicate that the purchase cost of the LSE was reduced through load management of customers with TSA systems. The introduction of TSA systems also reduced the volatility of market clearing price and reduced the whole-trade cost in an electricity market.

  16. Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

    Science.gov (United States)

    Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

    2014-01-01

    Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

  17. Effect of energy-regenerative braking on electric vehicle battery thermal management and control method based on simulation investigation

    International Nuclear Information System (INIS)

    Huang, Jingying; Qin, Datong; Peng, Zhiyuan

    2015-01-01

    Highlights: • A two-degree-of-freedom lumped thermal model is developed for battery. • The battery thermal model is integrated with vehicle driving model. • Real-time battery thermal responses is obtained. • Active control of current by regenerative braking ratio adjustment is proposed. • More energy is recovered with smaller battery temperature rise. - Abstract: Battery thermal management is important for the safety and reliability of electric vehicle. Based on the parameters obtained from battery hybrid pulse power characterization test, a two-degree-of-freedom lumped thermal model is established. The battery model is then integrated with vehicle driving model to simulate real-time battery thermal responses. An active control method is proposed to reduce heat generation due to regenerative braking. The proposed control method not only subjects to the braking safety regulation, but also adjusts the regenerative braking ratio through a fuzzy controller. By comparing with other regenerative braking scenarios, the effectiveness of the proposed strategy has been validated. According to the results, the proposed control strategy suppresses battery temperature rise by modifying the charge current due to regenerative braking. The overlarge components of current are filtered out whereas the small ones are magnified. Therefore, with smaller battery temperature rise, more energy is recovered. Compared to the traditional passive heat dissipating, the proposed active methodology is feasible and provides a novel solution for electric vehicle battery thermal management.

  18. The surface chemical properties of multi-walled carbon nanotubes modified by thermal fluorination for electric double-layer capacitor

    Science.gov (United States)

    Jung, Min-Jung; Jeong, Euigyung; Lee, Young-Seak

    2015-08-01

    The surfaces of multi-walled carbon nanotubes (MWCNTs) were thermally fluorinated at various temperatures to enhance the electrochemical properties of the MWCNTs for use as electric double-layer capacitor (EDLC) electrodes. The fluorine functional groups were added to the surfaces of the MWCNTs via thermal fluorination. The thermal fluorination exposed the Fe catalyst on MWCNTs, and the specific surface area increased due to etching during the fluorination. The specific capacitances of the thermally fluorinated at 100 °C, MWCNT based electrode increased from 57 to 94 F/g at current densities of 0.2 A/g, respectively. This enhancement in capacitance can be attributed to increased polarization of the thermally fluorinated MWCNT surface, which increased the affinity between the electrode surface and the electrolyte ions.

  19. Numerical investigation of the thermal and electrical performances for combined solar photovoltaic/thermal (PV/T) modules based on internally extruded fin flow channel

    Science.gov (United States)

    Deng, Y. C.; Li, Q. P.; Wang, G. J.

    2017-11-01

    A solar photovoltaic/thermal (PV/T) module based on internally extruded fin flow channel was investigated numerically in this paper. First of all, the structures of the thin plate heat exchanger and the PV/T module were presented. Then, a numerical model of the PV/T module considering solar irradiation, fluid flow and heat transfer was developed to analyze the performance of the module. Finally, the steady electrical and thermal efficiencies of the PV/T module at different inlet water temperatures and mass flow rates were achieved. These numerical results supply theory basis for practical application of the PV/T module.

  20. The nuclear thermal electric rocket: a proposed innovative propulsion concept for manned interplanetary missions

    Science.gov (United States)

    Dujarric, C.; Santovincenzo, A.; Summerer, L.

    2013-03-01

    Conventional propulsion technology (chemical and electric) currently limits the possibilities for human space exploration to the neighborhood of the Earth. If farther destinations (such as Mars) are to be reached with humans on board, a more capable interplanetary transfer engine featuring high thrust, high specific impulse is required. The source of energy which could in principle best meet these engine requirements is nuclear thermal. However, the nuclear thermal rocket technology is not yet ready for flight application. The development of new materials which is necessary for the nuclear core will require further testing on ground of full-scale nuclear rocket engines. Such testing is a powerful inhibitor to the nuclear rocket development, as the risks of nuclear contamination of the environment cannot be entirely avoided with current concepts. Alongside already further matured activities in the field of space nuclear power sources for generating on-board power, a low level investigation on nuclear propulsion has been running since long within ESA, and innovative concepts have already been proposed at an IAF conference in 1999 [1, 2]. Following a slow maturation process, a new concept was defined which was submitted to a concurrent design exercise in ESTEC in 2007. Great care was taken in the selection of the design parameters to ensure that this quite innovative concept would in all respects likely be feasible with margins. However, a thorough feasibility demonstration will require a more detailed design including the selection of appropriate materials and the verification that these can withstand the expected mechanical, thermal, and chemical environment. So far, the predefinition work made clear that, based on conservative technology assumptions, a specific impulse of 920 s could be obtained with a thrust of 110 kN. Despite the heavy engine dry mass, a preliminary mission analysis using conservative assumptions showed that the concept was reducing the required

  1. Simplified system for the pressure control of a Nucleo electric central of the BWR type

    International Nuclear Information System (INIS)

    Sanchez J, J.

    2003-01-01

    One of the main preoccupations of the electric power generator stations is the appropriate operation of the same ones. The operators must be qualified to respond in an adequate way and to be able to take to these power stations to an optimal, sure and stable operation condition under any circumstance. The Laboratory of Analysis in Nuclear Reactors Engineering (LAIRN) of the Engineering Faculty of UNAM (Fl) in collaboration with the International Atomic Energy Agency (IAEA), it develops an interactive classroom simulator in which simulations of the phenomena which take place in a nuclear power station are executed. The classroom simulator bases its operation on specialized nuclear codes feeding interactive graphic unfolding with those that it is possible to make a monitoring, supervision and control of the behavior of the power station under any operation regime, either in normal operation, transitory events or postulated accident sequence. The development of this classroom simulator includes a modular and re configurable structure. Due to it is indispensable to count with a higher inter activity with the system it is included the simulation of the control system of the plant and inside the same, one of those more important it is the reactor pressure control system. The present work describes the conceptual design and the used methodology for the development and implementation in the simulator of a simplified model of the pressure control system for a BWR generic central. The reach of the development will allow to accomplish the necessary tests to demonstrate that this has an adequate performance according to the carried out simplifications. (Author)

  2. Comparative Study of Electric Energy Storages and Thermal Energy Auxiliaries for Improving Wind Power Integration in the Cogeneration System

    Directory of Open Access Journals (Sweden)

    Yanjuan Yu

    2018-01-01

    Full Text Available In regards to the cogeneration system in Northern China, mainly supported by combined heat and power (CHP plants, it usually offers limited operation flexibility due to the joint production of electric and thermal power. For that large-scale wind farms included in the cogeneration system, a large amount of wind energy may have to be wasted. To solve this issue, the utilization of the electric energy storages and the thermal energy auxiliaries are recommended, including pumped hydro storage (PHS, compressed air energy storage (CAES, hydrogen-based energy storage (HES, heat storage (HS, electric boilers (EB, and heat pumps (HP. This paper proposes a general evaluation method to compare the performance of these six different approaches for promoting wind power integration. In consideration of saving coal consumption, reducing CO2 emissions, and increasing investment cost, the comprehensive benefit is defined as the evaluation index. Specifically, a wind-thermal conflicting expression (WTCE is put forward to simplify the formulation of the comprehensive benefit. Further, according to the cogeneration system of the West Inner Mongolia (WIM power grid, a test system is modelled to perform the comparison of the six different approaches. The results show that introducing the electric energy storages and the thermal energy auxiliaries can both contribute to facilitating wind power integration, and the HP can provide the best comprehensive benefit.

  3. Constructing nanoporous carbon nanotubes/Bi2Te3 composite for synchronous regulation of the electrical and thermal performances

    Science.gov (United States)

    Zhang, Qihao; Xu, Leilei; Zhou, Zhenxing; Wang, Lianjun; Jiang, Wan; Chen, Lidong

    2017-02-01

    Porous nanograined thermoelectric materials exhibit low thermal conductivity due to scattering of phonons by pores, which are favorable for thermoelectric applications. However, the benefit is not large enough to overcome the deficiency in the electrical performance. Herein, an approach is presented to reduce the thermal conductivity and synchronously enhance the electrical conductivity through constructing a nanoporous thermoelectric composite. Carbon nanotubes (CNTs) are truncated and homogeneously dispersed within the Bi2Te3 matrix by a cryogenic grinding (CG) technique for the first time, which efficiently suppress the Bi2Te3 grain growth and create nanopores with the size ranging from dozens to hundreds of nanometers. The lattice thermal conductivity is substantially decreased by broad wavelength phonon scattering resulting from nanopores, increased grain boundaries, and newly formed interfaces. Meanwhile, the electrical conductivity is improved due to the enhanced carrier mobility, which may originate from the bridging effect between the Bi2Te3 grains and CNTs. The maximum ZT is improved by almost a factor of 2 due to the simultaneous optimization of electrical and thermal performances. Our study demonstrates the superiority of constructing a bulk thermoelectric composite with nanopores by the uniform dispersion of CNTs through a CG technique for enhanced thermoelectric properties, which provides a wider approach to thermoelectric nanostructure engineering.

  4. Natural gas utilization in Santa Cruz thermal-electric power; A utilizacao de gas natural em Santa Cruz

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Mauricio F. de.; Lundeqvist, Carl G; Gomes, Gerson; Almeida, A E

    1994-12-31

    Use of natural gas as an alternative energy source on the thermo electric power plant of Santa Cruz are presented. Economic studies on hydroelectric power plants to use thermal generators during low water supply periods, costs of natural gas as a alternative energy fuel, and the engineer services to the conversion of fuel oil system, are discussed. 5 figs., 6 tabs.

  5. Novel thermal management system using boiling cooling for high-powered lithium-ion battery packs for hybrid electric vehicles

    Science.gov (United States)

    Al-Zareer, Maan; Dincer, Ibrahim; Rosen, Marc A.

    2017-09-01

    A thermal management system is necessary to control the operating temperature of the lithium ion batteries in battery packs for electrical and hybrid electrical vehicles. This paper proposes a new battery thermal management system based on one type of phase change material for the battery packs in hybrid electrical vehicles and develops a three dimensional electrochemical thermal model. The temperature distributions of the batteries are investigated under various operating conditions for comparative evaluations. The proposed system boils liquid propane to remove the heat generated by the batteries, and the propane vapor is used to cool the part of the battery that is not covered with liquid propane. The effect on the thermal behavior of the battery pack of the height of the liquid propane inside the battery pack, relative to the height of the battery, is analyzed. The results show that the propane based thermal management system provides good cooling control of the temperature of the batteries under high and continuous charge and discharge cycles at 7.5C.

  6. Impacts of propagating, frustrated and surface modes on radiative, electrical and thermal losses in nanoscale-gap thermophotovoltaic power generators

    Science.gov (United States)

    Bernardi, Michael P.; Dupré, Olivier; Blandre, Etienne; Chapuis, Pierre-Olivier; Vaillon, Rodolphe; Francoeur, Mathieu

    2015-01-01

    The impacts of radiative, electrical and thermal losses on the performances of nanoscale-gap thermophotovoltaic (nano-TPV) power generators consisting of a gallium antimonide cell paired with a broadband tungsten and a radiatively-optimized Drude radiator are analyzed. Results reveal that surface mode mediated nano-TPV power generation with the Drude radiator outperforms the tungsten radiator, dominated by frustrated modes, only for a vacuum gap thickness of 10 nm and if both electrical and thermal losses are neglected. The key limiting factors for the Drude- and tungsten-based devices are respectively the recombination of electron-hole pairs at the cell surface and thermalization of radiation with energy larger than the cell absorption bandgap. A design guideline is also proposed where a high energy cutoff above which radiation has a net negative effect on nano-TPV power output due to thermal losses is determined. It is shown that the power output of a tungsten-based device increases by 6.5% while the cell temperature decreases by 30 K when applying a high energy cutoff at 1.45 eV. This work demonstrates that design and optimization of nano-TPV devices must account for radiative, electrical and thermal losses. PMID:26112658

  7. Study of an electrical heating system with ductless air supply and shape-stabilized PCM for thermal storage

    International Nuclear Information System (INIS)

    Lin, Kunping; Zhang, Yinping; Di, Hongfa; Yang, Rui

    2007-01-01

    A kind of electrical floor heating system with a shape-stabilized phase change material (PCM) which has been studied at Tsinghua University in our previous studies, can provide space heating during the whole day and can be controlled conventionally. However, this is not suitable for office buildings where no space heating is needed at night. The effective control is very important for the heating system in such buildings. In this paper, we studied a kind of new electrical floor heating system with ductless air supply and shape-stabilized PCM for thermal storage in order to overcome the shortcomings of the passive under-floor electric heating system with thermal storage. In this paper, we investigated its thermal performance by experiments and simulation, calculated the effects of various factors and discussed the application feasibility in different climate regions. The results show that the total electrical energy consumption was shifted from the peak period to the off-peak period, which would provide significant economic benefits because of the different day and night electricity tariffs. The system can be designed by choosing PCM with proper melting temperature and be controlled by varying velocity of air supply in different conditions

  8. Lightning Strike Ablation Damage Influence Factors Analysis of Carbon Fiber/Epoxy Composite Based on Coupled Electrical-Thermal Simulation

    Science.gov (United States)

    Yin, J. J.; Chang, F.; Li, S. L.; Yao, X. L.; Sun, J. R.; Xiao, Y.

    2017-10-01

    According to the mathematical analysis model constructed on the basis of energy-balance relationship in lightning strike, and accompany with the simplified calculation strategy of composite resin pyrolysis degree dependent electrical conductivity, an effective three dimensional thermal-electrical coupling analysis finite element model of composite laminate suffered from lightning current was established based on ABAQUS, to elucidate the effects of lighting current waveform parameters and thermal/electrical properties of composite laminate on the extent of ablation damage. Simulated predictions agree well with the composite lightning strike directed effect experimental data, illustrating the potential accuracy of the constructed model. The analytical results revealed that extent of composite lightning strike ablation damage can be characterized by action integral validly, there exist remarkable power function relationships between action integral and visual damage area, projected damage area, maximum damage depth and damage volume of ablation damage, and enhancing the electrical conductivity and specific heat of composite, ablation damage will be descended obviously, power function relationships also exist between electrical conductivity, specific heat and ablation damage, however, the impact of thermal conductivity on the extent of ablation damage is not notable. The conclusions obtained provide some guidance for composite anti-lightning strike structure-function integration design.

  9. Simulation of thermal stresses in anode-supported solid oxide fuel cell stacks. Part II: Loss of gas-tightness, electrical contact and thermal buckling

    Science.gov (United States)

    Nakajo, Arata; Wuillemin, Zacharie; Van herle, Jan; Favrat, Daniel

    Structural stability issues in planar solid oxide fuel cells arise from the mismatch between the coefficients of thermal expansion of the components. The stress state at operating temperature is the superposition of several contributions, which differ depending on the component. First, the cells accumulate residual stresses due to the sintering phase during the manufacturing process. Further, the load applied during assembly of the stack to ensure electric contact and flatten the cells prevents a completely stress-free expansion of each component during the heat-up. Finally, thermal gradients cause additional stresses in operation. The temperature profile generated by a thermo-electrochemical model implemented in an equation-oriented process modelling tool (gPROMS) was imported into finite-element software (ABAQUS) to calculate the distribution of stress and contact pressure on all components of a standard solid oxide fuel cell repeat unit. The different layers of the cell in exception of the cathode, i.e. anode, electrolyte and compensating layer were considered in the analysis to account for the cell curvature. Both steady-state and dynamic simulations were performed, with an emphasis on the cycling of the electrical load. The study includes two different types of cell, operation under both thermal partial oxidation and internal steam-methane reforming and two different initial thicknesses of the air and fuel compressive sealing gaskets. The results generated by the models are presented in two papers: Part I focuses on cell cracking. In the present paper, Part II, the occurrences of loss of gas-tightness in the compressive gaskets and/or electrical contact in the gas diffusion layer were identified. In addition, the dependence on temperature of both coefficients of thermal expansion and Young's modulus of the metallic interconnect (MIC) were implemented in the finite-element model to compute the plastic deformation, while the possibilities of thermal buckling

  10. Stirling engines for low-temperature solar-thermal-electric power generation

    Science.gov (United States)

    der Minassians, Artin

    This dissertation discusses the design and development of a distributed solar-thermal-electric power generation system that combines solar-thermal technology with a moderate-temperature Stirling engine to generate electricity. The conceived system incorporates low-cost materials and utilizes simple manufacturing processes. This technology is expected to achieve manufacturing cost of less than $1/W. Since solar-thermal technology is mature, the analysis, design, and experimental assessment of moderate-temperature Stirling engines is the main focus of this thesis. The design, fabrication, and test of a single-phase free-piston Stirling engine prototype is discussed. This low-power prototype is designed and fabricated as a test rig to provide a clear understanding of the Stirling cycle operation, to identify the key components and the major causes of irreversibility, and to verify corresponding theoretical models. As a component, the design of a very low-loss resonant displacer piston subsystem is discussed. The displacer piston is part of a magnetic circuit that provides both a required stiffness and actuation forces. The stillness is provided by a magnetic spring, which incorporates an array of permanent magnets and has a very linear stiffness characteristic that facilitates the frequency tuning. In this prototype, the power piston is not mechanically linked to the displacer piston and forms a mass-spring resonating subsystem with the engine chamber gas spring and has resonant frequency matched to that of the displacer. The fabricated engine prototype is successfully tested and the experimental results are presented and discussed. Extensive experimentation on individual component subsystems confirms the theoretical models and design considerations, providing a sound basis for higher power Stirling engine designs for residential or commercial deployments. Multi-phase Stirling engine systems are also considered and analyzed. The modal analysis of these machines proves

  11. Technological solution for the protection of the environment (in the Central Research Inst. of Electric Power Industry, Tokyo, Japan)

    International Nuclear Information System (INIS)

    Glamochanin, Vlastimir

    1997-01-01

    As we approach the 21 century, the world finds itself confronting challenges regarding global-scale issues: economic development, the use of energy and natural resources, and environmental preservation. Moreover, these issues do not exist in a vacuum; they are all interrelated. They exert delicate effects on each other and can not be considered separately. If we continue as we have in the past, the earth will face an unprecedented crisis in the middle of coming century, in conjunction with the population explosion. (Susumu Yoda, President of the Central Research Inst. of Electric Power Industry, Tokyo, Japan). This paper presents a brief review of the research policy of the Japan Central Research Inst. of Electric Power Industry, regarding environmental preservation

  12. The approximate thermal-model-testing method for non-stationary temperature fields in central zones of fast reactor assemblies

    International Nuclear Information System (INIS)

    Mikhin, V.I.; Matukhin, N.M.

    2000-01-01

    The approach to generalization of the non-stationary heat exchange data for the central zones of the nuclear reactor fuel assemblies and the approximate thermal-model-testing criteria are proposed. The fuel assemblies of fast and water-cooled reactors with different fuel compositions have been investigated. The reason of the non-stationary heat exchange is the fuel-energy-release time dependence. (author)

  13. MOA: Magnetic Field Oscillating Amplified Thruster and its Application for Nuclear Electric and Thermal Propulsion

    International Nuclear Information System (INIS)

    Frischauf, Norbert; Hettmer, Manfred; Grassauer, Andreas; Bartusch, Tobias; Koudelka, Otto

    2006-01-01

    More than 60 years after the later Nobel laureate Hannes Alfven had published a letter stating that oscillating magnetic fields can accelerate ionised matter via magneto-hydrodynamic interactions in a wave like fashion, the technical implementation of Alfven waves for propulsive purposes has been proposed, patented and examined for the first time by a group of inventors. The name of the concept, utilising Alfven waves to accelerate ionised matter for propulsive purposes, is MOA - Magnetic field Oscillating Amplified thruster. Alfven waves are generated by making use of two coils, one being permanently powered and serving also as magnetic nozzle, the other one being switched on and off in a cyclic way, deforming the field lines of the overall system. It is this deformation that generates Alfven waves, which are in the next step used to transport and compress the propulsive medium, in theory leading to a propulsion system with a much higher performance than any other electric propulsion system. Based on computer simulations, which were conducted to get a first estimate on the performance of the system, MOA is a highly flexible propulsion system, whose performance parameters might easily be adapted, by changing the mass flow and/or the power level. As such the system is capable to deliver a maximum specific impulse of 13116 s (12.87 mN) at a power level of 11.16 kW, using Xe as propellant, but can also be attuned to provide a thrust of 236.5 mN (2411 s) at 6.15 kW of power. While space propulsion is expected to be the prime application for MOA and is supported by numerous applications such as Solar and/or Nuclear Electric Propulsion or even as an 'afterburner system' for Nuclear Thermal Propulsion, other terrestrial applications can be thought of as well, making the system highly suited for a common space-terrestrial application research and utilisation strategy. (authors)

  14. Analysis of breakdown on thermal and electrical measurements for SPIDER accelerating grids

    Energy Technology Data Exchange (ETDEWEB)

    Pesce, Alberto, E-mail: alberto.pesce@igi.cnr.it [Consorzio RFX - Associazione EURATOM-ENEA per la fusione, Corso Stati Uniti 4, 35127 Padova (Italy); Pomaro, Nicola [Consorzio RFX - Associazione EURATOM-ENEA per la fusione, Corso Stati Uniti 4, 35127 Padova (Italy)

    2011-10-15

    The PRIMA test facility, under realization in Padova, includes a full size plasma source prototype for ITER, called SPIDER (Source for the Production of Ions of Deuterium Extracted from Radio Frequency plasma). The effects of breakdown in the electrical insulation inside the ion source are analyzed with particular care to the embedded diagnostic system, i.e. the thermal and electrical measurements installed on the grids and ion source case and transferred by multipolar cables to the acquisition system, located inside the 100 kV insulated deck and hosting the ion source power supply, the signal conditioning and the acquisition cubicles. The breakdown affects strongly the measurements, so it has to be mitigated in order to guarantee adequate reliability of the whole measurement set. A parametric study has been carried out on a detailed circuital model for fast transients, implemented using SimPowerSystems{sup TM} tool of Matlab Simulink code. The model includes all the relevant conductors of the subsystems downstream the insulating transformer of the Accelerating Grids Power Supply (AGPS), i.e. the AGPS rectifier, the multipolar transmission line, the 100 kV High Voltage Deck, the ion source power supply and the ion source itself. In particular all the magnetic and capacitive couplings have been computed by a proper 2D fem model. The optimization of the cabling layout, of the wire screening and of the protection devices, like surge arresters and resistors, has been carried out through the accurate modeling of the circuit. The energy dissipated on each ion source surge arrester is estimated and adequate TSD (transient suppression devices) are selected. A peculiar and difficult to satisfy requirement is the high number of surges that the TSD has to withstand. Breakdowns between components polarized at different voltages have been considered, in order to inspect the worst condition during a breakdown.

  15. Analysis of Heat Transfer in Power Split Device for Hybrid Electric Vehicle Using Thermal Network Method

    Directory of Open Access Journals (Sweden)

    Jixin Wang

    2014-06-01

    Full Text Available This paper presents a rational prediction of temperature field on the differential hybrid system (DHS based on the thermal network method (TNM. The whole thermal network model is built by considering both the contact thermal resistance between gasket and planet gear and the temperature effect on the physical property parameters of lubricant. The contact thermal resistance is obtained by using the concept of contact branch thermal resistance and G-W elastic model. By building an elaborate thermal network model and computing models for power losses and thermal resistances between components, the whole temperature field of DHS under typical operating condition is predicted. Results show that thermal network method can be effectively used to predict the temperature distribution and the rule of temperature variation, the surface roughness significantly affects contact thermal conduction, and the decrease in the thermal resistance of the natural convection between air and DHS housing can effectively improve the thermal environment of DHS.

  16. A thermal and electrical dynamic mathematical model for squirrel cage induction motors; Modelamento matematico dinamico termico e eletrico de motores de inducao

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Ronaldo Martins de

    1996-01-01

    A thermal and electrical dynamic mathematical model for squirrel cage induction motors is presented. The electrical model is described by Park equation and the torque equation, while the thermal model is described by a system of four first order differential equations that represent the motor heat transfer process. The model presented can be used to determine thermal and electrical performance for any operation condition. However, it is suitable mainly for machines operating under continuously transient condition. The presented mathematical model also incorporate variation of rotor winding electrical parameters due to skin effect. (author)

  17. Thermal Effect on the Structural, Electrical, and Optical Properties of In-Line Sputtered Aluminum Doped Zinc Oxide Films Explored with Thermal Desorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Shang-Chou Chang

    2014-01-01

    Full Text Available This work investigates the thermal effect on the structural, electrical, and optical properties of aluminum doped zinc oxide (AZO films. The AZO films deposited at different temperatures were measured using a thermal desorption system to obtain their corresponding thermal desorption spectroscopy (TDS. In addition to obtaining information of thermal desorption, the measurement of TDS also has the effect of vacuum annealing on the AZO films. The results of measuring TDS imply part of the doped aluminum atoms do not stay at substituted zinc sites in AZO films. The (002 preferential direction of the AZO films in X-ray diffraction spectra shifts to a lower angle after measurement of TDS. The grain size grows and surface becomes denser for all AZO films after measurement of TDS. The carrier concentration, mobility, and average optical transmittance increase while the electrical resistivity decreases for AZO films after measurement of TDS. These results indicate that the AZO films deposited at 200°C are appropriate selections if the AZO films are applied in device fabrication of heat-produced process.

  18. Experimental study of thermal field deriving from an underground electrical power cable buried in non-homogeneous soils

    International Nuclear Information System (INIS)

    Lieto Vollaro, Roberto de; Fontana, Lucia; Vallati, Andrea

    2014-01-01

    The electrical cables ampacity mainly depends on the cable system operation temperature. To achieve a better cable utilization and reduce the conservativeness typically employed in buried cable design, an accurate evaluation of the heat dissipation through the cables and the surrounding soil is important. In the traditional method adopted by the International Electrotechnical Commission (IEC) and the Institute of Electrical and Electronics Engineers (IEEE) for the computation of the thermal resistance between an existing underground cable system and the external environment, it is still assumed that the soil is homogeneous and has uniform thermal conductivity. Numerical studies have been conducted to predict the temperature distribution around the cable for various configurations and thermal properties of the soil. The paper presents an experimental study conducted on a scale model to investigate the heat transfer of a buried cable, with different geometrical configurations and thermal properties of the soil, and to validate a simplified model proposed by the authors in 2012 for the calculation of the thermal resistance between the underground pipe or electrical cable and the ground surface, in cases where the filling of the trench is filled with layers of materials with different thermal properties. Results show that experimental data are in good agreement with the numerical ones. -- Highlights: • Heat transfer of a buried cable has been experimentally studied on a scale model. • Different configurations and thermal properties of the soil have been tested. • Authors previously proposed a simplified model and obtained numerical results. • Experimental results and numerical ones previously obtained were in accordance

  19. Fabrication and characterization of stearic acid/polyaniline composite with electrical conductivity as phase change materials for thermal energy storage

    International Nuclear Information System (INIS)

    Wang, Yi; Ji, Hui; Shi, Huan; Zhang, Ting; Xia, TianDong

    2015-01-01

    Highlights: • Stearic acid/polyaniline composite PCM with electrical conductivity was fabricated. • Stearic acid acted as thermal energy storage media and doping acid. • Latent heats of SA/PANI are as high as the same type composites. • Improved electrical conductivity of capsules is 0.7042 S cm −1 . - Abstract: This paper presents the experimental investigation on the thermal properties and electrical conductivity of the new microencapsulated phase change material by entrapping of stearic acid (SA) into PANI (polyaniline) shell through self-assembly method. Experimental results reveal that PANI nuclei grew on the surface of SA, and then copied its original morphological structure and finally exhibited peony flower-like morphology. The two components have good compatibility and have no chemical reaction both in the process of fabrication and subsequent use, while hydrogen bondings between the imino groups and carboxyl groups exist. The maximum mass fraction of stearic acid loaded in SA/PANI is determined as high as 62.1 wt% without seepage of melted SA from capsules. Due to the secondary doping with carboxyl group, the composite phase change material embedded with SA exhibits improved electrical conductivity from 0.3968 S cm −1 to 0.7042 S cm −1 when compared to PANI. The phase change temperatures and latent heats of SA/PANI are measured to be 55.6 °C and 113.02 J/g for melting and, 50.8 °C and 112.58 J/g for freezing, respectively. TG analysis test revealed that the prepared SA/PANI composite PCM has high thermal durability in working temperature range. Moreover, the results of DSC, FT-IR, TG, conductivity investigation and thermal cycling test are all show that the thermal reliability and electrical conductivity of the SA/APNI have imperceptible changes. In total, the additional electrical conductivity, high heat storage potential and good thermal reliability and stability facilitated SA/PANI to be considered as a viable candidate for thermal

  20. Calculating electrical and thermal characteristics of multiple PV array configurations installed in the tropics

    International Nuclear Information System (INIS)

    Effendy Ya’acob, M.; Hizam, Hashim; Htay, Myo Than; Radzi, M. Amran M.; Khatib, Tamer; Bakri A, M.

    2013-01-01

    Highlights: • Electrical and temperature characteristics of multiple PV array configurations. • Ten months tropical field analysis implying SNL model for array parameter. • Review on T c equations and GEV analysis for rapid fluctuating environmental data. • CPV array projects the highest ΔT of 2.72 °C with G e of 0.36 W/m 2 . • Fixed flat array produces highest parameter values of I sc , V oc , I mp , V mp and P mp . - Abstract: This study intends to define the electrical characteristics and temperature equations of PV array installed in the tropics based on Sandia National Laboratory (SNL) model. Ten units of 1 kW rated PV array namely Fixed Flat (FF), Tracking Flat (TF) and Concentrating (CPV) have been installed at Universiti Putra Malaysia (UPM), Serdang District, Malaysia at the coordinate of 2°59′20′′N:101°43′30′′E with tropical-based ground conditions. Electrical characteristics are the main elements of contributions where five operating conditions for CEEG PV Module are applied based on the SNL model to produce array parameter values. It is found that FF array projects the highest operating value of 12.06 A (I sc ), 11.55 A (I mp ), 524.78 V (V oc ), 89.5 V (V mp ), and 1033.7 W (P mp ) with good regression fit and strong correlation R 2 of more than 0.5. The versatility and accuracy of this work have been validated and applied for three different types of PV array system installed in the equatorial doldrum spot of uniform temperature–irradiance, high in humidity–rainfall and generally light wind field conditions. The parameters are calculated using filtered field data sampled at STC of 5% tolerance. Focal point of calculating array temperature (T array ) as means of thermal effect on multiple PV array configurations is highlighted based on recent study on T c equations and Generalized Extreme Value (GEV) analysis using field data at site

  1. Hierarchically interconnected porous scaffolds for phase change materials with improved thermal conductivity and efficient solar-to-electric energy conversion.

    Science.gov (United States)

    Yang, Jie; Yu, Peng; Tang, Li-Sheng; Bao, Rui-Ying; Liu, Zheng-Ying; Yang, Ming-Bo; Yang, Wei

    2017-11-23

    An ice-templating self-assembly strategy and a vacuum impregnation method were used to fabricate polyethylene glycol (PEG)/hierarchical porous scaffold composite phase change materials (PCMs). Hierarchically interconnected porous scaffolds of boron nitride (BN), with the aid of a small amount of graphene oxide (GO), endow the composite PCMs with high thermal conductivity, excellent shape-stability and efficient solar-to-electric energy conversion. The formation of a three-dimensional (3D) thermally conductive pathway in the composites contributes to improving the thermal conductivity up to 2.36 W m -1 K -1 at a relatively low content of BN (ca. 23 wt%). This work provides a route for thermally conductive and shape-stabilized composite PCMs used as energy storage materials.

  2. A central solar-industrial waste heat heating system with large scale borehole thermal storage

    NARCIS (Netherlands)

    Guo, F.; Yang, X.; Xu, L.; Torrens, I.; Hensen, J.L.M.

    2017-01-01

    In this paper, a new research of seasonal thermal storage is introduced. This study aims to maximize the utilization of renewable energy source and industrial waste heat (IWH) for urban district heating systems in both heating and non-heating seasons through the use of large-scale seasonal thermal

  3. Optical and electrical properties of thermally evaporated In49Se48Sn3 films

    International Nuclear Information System (INIS)

    Salem, A.M.; El-Gendy, Y.A.; El-Sayad, E.A.

    2009-01-01

    Nearly stoichiometric thin films of In 49 Se 48 Sn 3 were deposited at room temperature, by conventional thermal evaporation of the presynthesized materials, onto precleaned glass substrates. The microstructural studies on the as-deposited and annealed films, using transmission electron microscopy and diffraction (TEMD), revealed that the as-deposited films are amorphous in nature, while those annealed at 498 K are crystalline. The optical properties of the investigated films were determined from the transmittance and reflectance data, in the spectral range 650-2500 nm. An analysis of the optical absorption spectra revealed a non-direct energy gap characterizing the amorphous films, while both allowed and forbidden direct energy gaps characterized the crystalline films. The electrical resistance of the deposited films was carried out during heating and cooling cycles in the temperature range 300-600 K. The results show an irreproducible behavior, while after crystallization the results become reproducible. The analysis of the temperature dependence of the resistance (ln(R) vs. 1000/T) for crystalline films shows two straight lines corresponding to both extrinsic and intrinsic conduction. The room temperature I-V characteristics of the as-deposited films sandwiched between similar Ag metal electrodes shows an ohmic behavior, while non-ohmic behavior attributed to space charge limited conduction has been observed when the films are sandwiched between dissimilar Ag/Al metal electrodes.

  4. Chemical Surface, Thermal and Electrical Characterization of Nafion Membranes Doped with IL-Cations

    Directory of Open Access Journals (Sweden)

    María del Valle Martínez de Yuso

    2014-04-01

    Full Text Available Surface and bulk changes in a Nafion membrane as a result of IL-cation doping (1-butyl-3-methylimidazolium tetrafluoroborate or BMIM+BF4 and phenyltrimethylammonium chloride or TMPA+Cl− were studied by X-ray photoelectron spectroscopy (XPS, contact angle, differential scanning calorimetry (DSC and impedance spectroscopy (IS measurements performed with dry samples after 24 h in contact with the IL-cations BMIM+ and TMPA+. IL-cations were selected due to their similar molecular weight and molar volume but different shape, which could facilitate/obstruct the cation incorporation in the Nafion membrane structure by proton/cation exchange mechanism. The surface coverage of the Nafion membrane by the IL-cations was confirmed by XPS analysis and contact angle, while the results obtained by the other two techniques (DSC and IS seem to indicate differences in thermal and electrical behaviour depending on the doping-cation, being less resistive the Nafion/BMIM+ membrane. For that reason, determination of the ion transport number was obtained for this membrane by measuring the membrane or concentration potential with the samples in contact with HCl solutions at different concentrations. The comparison of these results with those obtained for the original Nafion membrane provides information on the effect of IL-cation BMIM+ on the transport of H+ across wet Nafion/BMIM+ doped membranes.

  5. Study of thermal and electrical properties exhibited by two ferroelectric self assembly systems

    Science.gov (United States)

    Vijayakumar, V. N.; Madhu Mohan, M. L. N.

    2011-04-01

    Two series of inter hydrogen bonded ferroelectric liquid crystals have been isolated. In one of the series hydrogen bond is formed between p- n-alkyloxy benzoic acids and (S)-1,2-cholo-3-(4-hydroxy) phenyl propionic acid (CTy + nOBA) while in the other it is formed between p- n-alkyl benzoic acids and (S)-1,2-cholo-3-(4-hydroxy) phenyl propionic acid (CTy + nBA). Detailed synthetic route for the isolation of these compounds is discussed. Formation of the ferroelectric self assembly systems has been evinced through FTIR studies. The positional influence of oxygen atom is investigated from the thermal and electrical characterization of both the series. Polarizing optical microscope (POM) studies on CTy + nBA hydrogen bonded complexes reveals that they exhibit single phase variance while the other complex CTy + nOBA exhibit rich phase polymorphism. It is observed that the presence of oxygen atom enhances phase abundance. Phase diagrams for both the complexes are constructed from the DSC and POM studies. Dielectric relaxations and activation energies have been carried out for various phases in CTy + 8OBA and CTy + 8BA complexes. It has been observed that the oxygen atom originates type I relaxation process. Two molecular modeling have been assigned to account for the dielectric relaxation process observed in both the HBFLC series.

  6. Summary assessment of solar thermal parabolic dish technology for electrical power generation

    Science.gov (United States)

    Penda, P. L.; Fujita, T.; Lucas, J. W.

    1985-01-01

    An assessment is provided of solar thermal parabolic dish technology for electrical power generation. The assessment is based on the development program undertaken by the Jet Propulsion Laboratory for the U.S. Department of Energy and covers the period from the initiation of the program in 1976 through mid-1984. The program was founded on developing components and subsystems that are integrated into parabolic dish power modules for test and evaluation. The status of the project is summarized in terms of results obtained through testing of modules, and the implications of these findings are assessed in terms of techno-economic projections and market potential. The techno-economic projections are based on continuation of an evolutionary technological development program and are related to the accomplishments of the program as of mid-1984. The accomplishments of the development effort are summarized for each major subsystem including concentrators, receivers, and engines. The ramifications of these accomplishments are assessed in the context of developmental objectives and strategies.

  7. Chaotic artificial immune approach applied to economic dispatch of electric energy using thermal units

    International Nuclear Information System (INIS)

    Santos Coelho, Leandro dos; Mariani, Viviana Cocco

    2009-01-01

    The economic dispatch problem (EDP) is an optimization problem useful in power systems operation. The objective of the EDP of electric power generation, whose characteristics are complex and highly non-linear, is to schedule the committed generating unit outputs so as to meet the required load demand at minimum operating cost while satisfying system constraints. Recently, as an alternative to the conventional mathematical approaches, modern heuristic optimization techniques have been given much attention by many researchers due to their ability to find an almost global optimal solution in EDPs. As special mechanism to avoid being trapped in local minimum, the ergodicity property of chaotic sequences has been used as optimization technique in EDPs. Based on the chaos theory, this paper discusses the design and validation of an optimization procedure based on a chaotic artificial immune network approach based on Zaslavsky's map. The optimization approach based on chaotic artificial immune network is validated for a test system consisting of 13 thermal units whose incremental fuel cost function takes into account the valve-point loading effects. Simulation results and comparisons show that the chaotic artificial immune network approach is competitive in performance with other optimization approaches presented in literature and is also an attractive tool to be used on applications in the power systems field.

  8. Structural, thermal and electrical characterizations of multiwalled carbon nanotubes and polyaniline composite

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Kamal, E-mail: singhkamal204@gmail.com; Garg, Leena; Singh, Jaspal [Department of Applied Sciences, Chandigarh University, Gharuan, Mohali (India); Kumar, Sanjeev [Applied Sciences Department, PEC University of Technology, Chandigarh (India); Sharma, Amit L. [Central Scientific Instrumentation Organization, Sector 30, Chandigarh (India)

    2016-05-06

    The undoped and doped composite of MWNTs (Multiwalled Carbon Nanotubes) with PANI (/Polyaniline) was prepared by chemical oxidative polymerization. The MWNTs/PANI composites have been characterized by using various techniques like Thermogravometric Analysis (TGA), Fourier transform infrared (FT-IR) spectrometer and Field emission scanning electron microscope (FE-SEM) and conductivity measurement by using two probe method. TGA results has shown that thermal stability followed the pattern undoped MWNTs/PANI composite < doped MWNTs/PANI composite. FE-SEM micrographs demonstrated the morphological changes on the surface of MWNTs as a result of composite formation. Fourier transformed infrared (FT-IR) spectra ascertained the formation of the composite. Study of electrical characteristics demonstrated that the doped MWNTs/PANI composite (1.2 × 10{sup 1} Scm{sup −1}) have better conductivity than the undoped MWNTs/PANI composite (10{sup −4} Scm{sup −1}). These CNTs based polymeric composites are of great importance in developing new nano-scale devices for future chemical, mechanical and electronic applications.

  9. Electrical resistivity and thermal conductivity of SiC/Si ecoceramics prepared from sapele wood biocarbon

    Science.gov (United States)

    Parfen'eva, L. S.; Orlova, T. S.; Smirnov, B. I.; Smirnov, I. A.; Misiorek, H.; Mucha, J.; Jezowski, A.; Gutierrez-Pardo, A.; Ramirez-Rico, J.

    2012-10-01

    Samples of β-SiC/Si ecoceramics with a silicon concentration of ˜21 vol % have been prepared using a series of consecutive procedures (carbonization of sapele wood biocarbon, synthesis of high-porosity biocarbon with channel-type pores, infiltration of molten silicon into empty channels of the biocarbon, formation of β-SiC, and retention of residual silicon in channels of β-SiC). The electrical resistivity ρ and thermal conductivity κ of the β-SiC/Si ecoceramic samples have been measured in the temperature range 5-300 K. The values of ρ{Si/chan}( T) and κ{Si/chan}( T) have been determined for silicon Sichan located in β-SiC channels of the synthesized β-SiC/Si ecoceramics. Based on the performed analysis of the obtained results, the concentration of charge carriers (holes) in Sichan has been estimated as p ˜ 1019 cm-3. The factors that can be responsible for such a high value of p have been discussed. The prospects for practical application of β-SiC/Si ecoceramics have been considered.

  10. Beyond electricity: The potential of ocean thermal energy and ocean technology ecoparks in small tropical islands

    International Nuclear Information System (INIS)

    Osorio, Andrés F.; Arias-Gaviria, Jessica; Devis-Morales, Andrea; Acevedo, Diego; Velasquez, Héctor Iván; Arango-Aramburo, Santiago

    2016-01-01

    Small islands face difficult challenges to guarantee energy, freshwater and food supply, and sustainable development. The urge to meet their needs, together with the mitigation and adaptation plans to address climate change, have led them to develop renewable energy systems, with a special interest in Ocean Thermal Energy Conversion (OTEC) in tropical islands. Deep Ocean Water (DOW) is a resource that can provide electricity (through OTEC in combination with warm surface water), low temperatures for refrigeration, and nutrients for food production. In this paper we propose an Ocean Technology Ecopark (OTEP) as an integral solution for small islands that consists of an OTEC plant, other alternative uses of DOW, and a Research and Development (R&D) center. We present an application of OTEP to San Andres, a Colombian island that meets all the necessary conditions for the implementation of OTEC technology, water desalinization, and a business model for DOW. We present the main entrance barriers and a four-stage roadmap for the consolidation and sustainability of the OTEP. - Highlights: • Small islands face problems such as development, energy, freshwater and food supply. • Tropical islands with access to deep ocean water can use OTEC all year round. • An Ocean Ecopark is proposed as an integral solution for San Andrés Island, Colombia. • The Ecopark consists of OTEC, desalinization, SWAC, greenhouses, and R&D activities. • This article discusses entrance barriers and presents a four-stage roadmap

  11. Thermal Characteristics of an Oscillating Heat Pipe Cooling System for Electric Vehicle Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Ri-Guang Chi

    2018-03-01

    Full Text Available The heat generation of lithium ion batteries in electric vehicles (EVs leads to a degradation of energy capacity and lifetime. To solve this problem, a new cooling concept using an oscillating heat pipe (OHP is proposed. In the present study, an OHP has been adopted for Li-ion battery cooling. Due to the limited space in EVs, the cooling channel is installed on the bottom of the battery module. In the bottom cooling method with an OHP, generated heat can be dissipated easily and conveniently. However, most studies on heat pipes have used bottom heating and top or side cooling methods, so we investigate the various effects of parameters with a top heating/bottom cooling mode with the OHP, i.e., the inclination angle of the system, amount of working fluid charged, the heating amount, and the cold plate temperature with ethanol as a working fluid. The experimental results show that the thermal resistance (0.6 °C/W and uneven pulsating features influence the heat transfer performance. A heater used as a simulated battery was sustained under 60 °C under 10 W and 14 W heating conditions. This indicates that the proposed cooling system with the bottom cooling is feasible for use as an EV’s battery cooling system.

  12. Chitosan nanocomposite films: enhanced electrical conductivity, thermal stability, and mechanical properties.

    Science.gov (United States)

    Marroquin, Jason B; Rhee, K Y; Park, S J

    2013-02-15

    A novel, high-performance Fe(3)O(4)/MWNT/Chitosan nanocomposite has been prepared by a simple solution evaporation method. A significant synergistic effect of Fe(3)O(4) and MWNT provided enhanced electrical conductivity, mechanical properties, and thermal stability on the nanocomposites. A 5% (wt) loading of Fe(3)O(4)/MWNT in the nanocomposite increased conductivity from 5.34×10(-5) S/m to 1.49×10(-2) S/m compared to 5% (wt) MWNT loadings. The Fe(3)O(4)/MWNT/Chitosan films also exhibited increases in tensile strength and modulus of 70% and 155%, respectively. The integral procedure decomposition temperature (IPDT) was enhanced from 501 °C to 568 °C. These effects resulted from a number of factors: generation of a greater number of conductive channels through interactions between MWNT and Fe(3)O(4) surfaces, a higher relative crystallinity, the antiplasticizing effects of Fe(3)O(4), a restricted mobility and hindrance of depolymerization of the Chitosan chain segments, as well as uniform distribution, improved dispersion, and strong interfacial adhesion between the MWNT and Chitosan matrix. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Electrical characterization of 10B doped diamond irradiated with low thermal neutron fluence

    International Nuclear Information System (INIS)

    Reed, M.L.; Reed, M.J.; Jagannadham, K.; Verghese, K.; Bedair, S.M.; El-Masry, N.; Butler, J.E.

    2004-01-01

    A sample of 10 B isotope doped diamond was neutron irradiated to a thermal fluence of 1.3x10 19 neutron cm -2 . The diamond sample was cooled continuously during irradiation in a nuclear reactor. 7 Li is formed by nuclear transmutation reaction from 10 B. Characterization for electrical conductance in the temperature range of 160 K 10 B doped sample and the 10 B doped and irradiated sample. The unirradiated diamond sample showed p-type conductance at higher temperature (T>200 K) and p-type surface conductance at lower temperature (T 7 Li that is formed by nuclear transmutation reaction from 10 B atoms. Also, compensation of n-type carriers from 7 Li by p-type carriers from 10 B is used to interpret the conductance above 400 K. A low concentration of radiation induced defects, absence of defect complexes, and the low activation energy of n-type 7 Li are thought responsible for the observed variation of conductance in the irradiated diamond. The present results illustrate that neutron transmutation from 10 B doped diamond is a useful method to achieve n-type conductivity in diamond

  14. Optical, thermal and electrical properties of polybenzimidazoles derived from substituted benzimidazoles

    Science.gov (United States)

    Anand, Siddeswaran; Muthusamy, Athianna

    2017-11-01

    Three benzimidazole monomers synthesized by condensing various substituted phenolic aldehydes with 4-methylphenylenediamine were converted in to polymers by oxidative polycondensation. The structure of the monomers and polymers were confirmed by various spectroscopic techniques. Electronic distribution of molecular frontier orbitals and optimized geometries of monomers were calculated by Gaussian 09 package. The spectral results showed that the repeating units are connected through both Csbnd C and Csbnd Osbnd C linkages. Both polymers and monomers are showing good fluorescence emission in blue region. The electrical conductivity of I2 doped PBIs was measured using two point probe technique. The conductivities of PBIs were compared on the basis of the charge densities obtained from Huckel method on imidazole nitrogen which is involved in iodine coordination. The conductivity of polymers increases with increase in iodine vapour contact time. The dielectric properties of the synthesized polymers have been investigated at different temperature and frequency. Among the PBIs, PBIOP is having greater thermal stability and is shown by high carbines residues of around 50% at 500 °C in thermogravimetric analysis.

  15. Design optimization of electric vehicle battery cooling plates for thermal performance

    Science.gov (United States)

    Jarrett, Anthony; Kim, Il Yong

    The performance of high-energy battery cells utilized in electric vehicles (EVs) is greatly improved by adequate temperature control. An efficient thermal management system is also desirable to avoid diverting excessive power from the primary vehicle functions. In a battery cell stack, cooling can be provided by including cooling plates: thin metal fabrications which include one or more internal channels through which a coolant is pumped. Heat is conducted from the battery cells into the cooling plate, and transported away by the coolant. The operating characteristics of the cooling plate are determined in part by the geometry of the channel; its route, width, length, etc. In this study, a serpentine-channel cooling plate is modeled parametrically and its characteristics assessed using computational fluid dynamics (CFD). Objective functions of pressure drop, average temperature, and temperature uniformity are defined and numerical optimization is carried out by allowing the channel width and position to vary. The optimization results indicate that a single design can satisfy both pressure and average temperature objectives, but at the expense of temperature uniformity.

  16. A Model of Electrically Stimulated Auditory Nerve Fiber Responses with Peripheral and Central Sites of Spike Generation

    DEFF Research Database (Denmark)

    Joshi, Suyash Narendra; Dau, Torsten; Epp, Bastian

    2017-01-01

    . A single ANF is modeled as a network of two exponential integrateand-fire point-neuron models, referred to as peripheral and central axons of the ANF. The peripheral axon is excited by the cathodic charge, inhibited by the anodic charge, and exhibits longer spike latencies than the central axon......A computational model of cat auditory nerve fiber (ANF) responses to electrical stimulation is presented. The model assumes that (1) there exist at least two sites of spike generation along the ANF and (2) both an anodic (positive) and a cathodic (negative) charge in isolation can evoke a spike......; the central axon is excited by the anodic charge, inhibited by the cathodic charge, and exhibits shorter spike latencies than the peripheral axon. The model also includes subthreshold and suprathreshold adaptive feedback loops which continuously modify the membrane potential and can account for effects...

  17. Numerical study on optical and electric-thermal performance for solar concentrating PV/T air system

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Hybrid photovoltaic/thermal(PV/T)system with solar concentrator is an effective way to improve solar energy conversion efficiency.In this work,a single-pass PV/T air system with a three-trough compound parabolic concentrator(CPC)of concentration ratio 2.0 is designed and the solar incident distributions at the solar cell surface are calculated by ray tracing method.Based on energy balance,the heat transfer models of all main components in this system are developed.The effects of some main designing and operational parameters on the electric-thermal performance of the system are analyzed. The results show that the solar radiation intensity can be higher than 1200 W/m 2 at most area of the cell surface.The temperature of the air and cell surface increases along the length of the system.Thus the system efficiency of the CPC is higher than that of the system without the CPC.The thermal efficiency, exergy and electrical efficiency of this CPC system increase with increasing of the air mass flow rate and the length of the system.With increasing packing fraction the electrical efficiency increases,but the thermal efficiency decreases.The exergy efficiency increases slightly with the packing fraction rising.The data obtained in this work are valuable for the design and operation for this kind of solar concentrating PV/T systems.

  18. Thermal equilibrium of pure electron plasmas across a central region of magnetic surfaces

    Science.gov (United States)

    Hahn, Michael; Pedersen, Thomas Sunn

    2009-06-01

    Measurements of the equilibria of plasmas created by emission from a biased filament located off the magnetic axis in the Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois et al., Fusion Sci. Technol. 50, 372 (2006)] show that such plasmas have equilibrium properties consistent with the inner surfaces being in a state of cross-surface thermal equilibrium. Numerical solutions to the equilibrium equation were used to fit the experimental data and demonstrate consistency with cross-surface thermal equilibrium. Previous experiments in CNT showed that constant temperatures across magnetic surfaces are characteristic of CNT plasmas, implying thermal confinement times much less than particle confinement times. These results show that when emitting off axis there is a volume of inner surfaces where diffusion into that region is balanced by outward transport, producing a Boltzmann distribution of electrons. When combined with the low thermal energy confinement time this is a cross-surface thermal equilibrium.

  19. Thermal equilibrium of pure electron plasmas across a central region of magnetic surfaces

    International Nuclear Information System (INIS)

    Hahn, Michael; Pedersen, Thomas Sunn

    2009-01-01

    Measurements of the equilibria of plasmas created by emission from a biased filament located off the magnetic axis in the Columbia Non-neutral Torus (CNT) [T. S. Pedersen, J. P. Kremer, R. G. Lefrancois et al., Fusion Sci. Technol. 50, 372 (2006)] show that such plasmas have equilibrium properties consistent with the inner surfaces being in a state of cross-surface thermal equilibrium. Numerical solutions to the equilibrium equation were used to fit the experimental data and demonstrate consistency with cross-surface thermal equilibrium. Previous experiments in CNT showed that constant temperatures across magnetic surfaces are characteristic of CNT plasmas, implying thermal confinement times much less than particle confinement times. These results show that when emitting off axis there is a volume of inner surfaces where diffusion into that region is balanced by outward transport, producing a Boltzmann distribution of electrons. When combined with the low thermal energy confinement time this is a cross-surface thermal equilibrium.

  20. Current, voltage and temperature distribution modeling of light-emitting diodes based on electrical and thermal circuit analysis

    International Nuclear Information System (INIS)

    Yun, J; Shim, J-I; Shin, D-S

    2013-01-01

    We demonstrate a modeling method based on the three-dimensional electrical and thermal circuit analysis to extract current, voltage and temperature distributions of light-emitting diodes (LEDs). In our model, the electrical circuit analysis is performed first to extract the current and voltage distributions in the LED. Utilizing the result obtained from the electrical circuit analysis as distributed heat sources, the thermal circuit is set up by using the duality between Fourier's law and Ohm's law. From the analysis of the thermal circuit, the temperature distribution at each epitaxial film is successfully obtained. Comparisons of experimental and simulation results are made by employing an InGaN/GaN multiple-quantum-well blue LED. Validity of the electrical circuit analysis is confirmed by comparing the light distribution at the surface. Since the temperature distribution at each epitaxial film cannot be obtained experimentally, the apparent temperature distribution is compared at the surface of the LED chip. Also, experimentally obtained average junction temperature is compared with the value calculated from the modeling, yielding a very good agreement. The analysis method based on the circuit modeling has an advantage of taking distributed heat sources as inputs, which is essential for high-power devices with significant self-heating. (paper)

  1. Anisotropic electrical, thermal and magnetic properties of Al{sub 13}Ru{sub 4} decagonal quasicrystalline approximant

    Energy Technology Data Exchange (ETDEWEB)

    Wencka, Magdalena [Polish Academy of Sciences, Poznan (Poland). Inst. of Molecular Physics; Vrtnik, Stanislav; Kozelj, Primoz; Dolinsek, Janez [Ljubljana Univ. (Slovenia). Faculty of Mathematics and Physics; Jozef Stefan Institute, Ljubljana (Slovenia); Jaglicic, Zvonko [Ljubljana Univ. (Slovenia). Inst. of Mathematics, Physics and Mechanics; Gille, Peter [Muenchen Univ. (Germany). Crystallography Section

    2017-09-01

    We present measurements of the anisotropic electrical and thermal transport coefficients (the electrical resistivity, the thermoelectric power, the thermal conductivity), the magnetization and the specific heat of the Al{sub 13}Ru{sub 4} monoclinic approximant to the decagonal quasicrystal, in comparison to the isostructural Al{sub 13}Fe{sub 4}. The electrical and thermal transport parameters of Al{sub 13}Ru{sub 4} were found to exhibit significant anisotropy, qualitatively similar to that found previously in the Al{sub 13}Fe{sub 4} (P. Popcevic, et al., Phys. Rev. B 2010, 81, 184203). The crystallographic b direction, corresponding to the stacking direction of the (a,c) atomic planes, is the most conducting direction for the electricity and heat. The thermopower is strongly anisotropic with a complicated temperature dependence, exhibiting maxima, minima, crossovers and sign change. The electronic density of states (DOS) at the Fermi energy is reduced to 35% of the DOS of Al metal. The magnetic susceptibility is diamagnetic and the diamagnetism is by a factor of 2 stronger for the magnetic field along the stacking b direction.

  2. Optimal Allocation of Thermal-Electric Decoupling Systems Based on the National Economy by an Improved Conjugate Gradient Method

    Directory of Open Access Journals (Sweden)

    Shuang Rong

    2015-12-01

    Full Text Available Aiming to relieve the large amount of wind power curtailment during the heating period in the North China region, a thermal-electric decoupling (TED approach is proposed to both bring down the constraint of forced power output of combined heat and power plants and increase the electric load level during valley load times that assist the power grid in consuming more wind power. The operating principles of the thermal-electric decoupling approach is described, the mathematical model of its profits is developed, the constraint conditions of its operation are listed, also, an improved parallel conjugate gradient is utilized to bypass the saddle problem and accelerate the optimal speed. Numerical simulations are implemented and reveal an optimal allocation of TED which with a rated power of 280 MW and 185 MWh heat storage capacity are possible. This allocation of TED could bring approximately 16.9 billion Yuan of economic profit and consume more than 80% of the surplus wind energy which would be curtailed without the participation of TED. The results in this article verify the effectiveness of this method that could provide a referential guidance for thermal-electric decoupling system allocation in practice.

  3. Alternative central-station electric power generation technologies: a consistent engineering-economic framework of comparison

    International Nuclear Information System (INIS)

    Baughman, M.L.; Gordon, J.B.; Woodson, H.H.

    1983-01-01

    The electric utility sector is an intermediate processing sector of the economy that utilizes the factor inputs of labor, capital, and materials to process and convert chemical, nuclear, and other basic energy forms into electricity. The electricity is then delivered to and consumed by other intermediate or final users for purposes of heating, cooling, lighting, motive power, and materials processing. The economics of electricity supply encompass not only the selection of the basic energy form to be converted but also the selection of possible physical conversion processes to accomplish the conversion. The conversion processes can vary immensely in technical detail, physical configuration, and the basic scientific principle governing their operation. But whatever the design and technical detail, the basic purpose is to process some form of energy and manufacture electricity

  4. Direct thermal to electrical energy conversion using 9.5/65/35 PLZT ceramics in the ergodic relaxor phase.

    Science.gov (United States)

    Chin, Thomas K; Lee, Felix Y; McKinley, Ian M; Goljahi, Sam; Lynch, Christopher S; Pilon, Laurent

    2012-11-01

    This paper reports on direct thermal to electrical energy conversion by performing the Olsen cycle on 9.5/65/35 lead lanthanum zirconate titanate (PLZT). The Olsen cycle consists of two isothermal and two isoelectric field processes in the electric displacement versus electric field diagram. It was performed by alternatively dipping the material in hot and cold dielectric fluid baths under specified electric fields. The effects of applied electric field, sample thickness, electrode material, operating temperature, and cycle frequency on the energy and power densities were investigated. A maximum energy density of 637 ± 20 J/L/cycle was achieved at 0.054 Hz with a 250-μm-thick sample featuring Pt electrodes and coated with a silicone conformal coating. The operating temperatures varied between 3°C and 140°C and the electric field was cycled between 0.2 and 6.0 MV/m. A maximum power density of 55 ± 8 W/L was obtained at 0.125 Hz under the same operating temperatures and electric fields. The dielectric strength of the material, and therefore the energy and power densities generated, increased when the sample thickness decreased from 500 to 250 μm. Furthermore, the electrode material was found to have no significant effect on the energy and power densities for samples subject to the same operating temperatures and electric fields. However, samples with electrode material possessing thermal expansion coefficients similar to that of PLZT were capable of withstanding larger temperature swings. Finally, a fatigue test showed that the power generation gradually degraded when the sample was subject to repeated thermoelectrical loading.

  5. A detailed thermal-electrical model of three photovoltaic/thermal (PV/T) hybrid air collectors and photovoltaic (PV) module: Comparative study under Algiers climatic conditions

    International Nuclear Information System (INIS)

    Slimani, Mohamed El Amine; Amirat, Madjid; Kurucz, Ildikó; Bahria, Sofiane; Hamidat, Abderrahmane; Chaouch, Wafa Braham

    2017-01-01

    Highlights: • A detailed thermal and electrical model for PV and PV/T systems has been presented. • The developed numerical model was validated successfully with previously published experimental results. • A comparative study between four solar devices (PV and PV/T systems) was carried out. • The experimental weather conditions of Algiers site are used in the numerical model. • The glazed double-pass photovoltaic/thermal air collector shows the best overall energy efficiency. - Abstract: The thermal photovoltaic hybrid collector is a genuine cogeneration technology; it can produce electricity and heat simultaneously. In this paper, a comparative study is presented between four solar device configurations: photovoltaic module (PV-I), conventional hybrid solar air collector (PV/T-II), glazed hybrid solar air collector (PV/T-III) and glazed double-pass hybrid solar air collector (PV/T-IV). A numerical model is developed and validated through experimental results indicated in the previous literature. The numerical model takes the heat balance equations and different thermal and electrical parameters into account for each configuration included in this study, the energy performances are evaluated with a sample weather data of Algiers site. The numerical results show that the daily average of overall energy efficiency reaches: 29.63%, 51.02%, 69.47% and 74% for the first (PV-I), the second (PV/T-II), the third (PV/T-III) and the fourth (PV/T-IV) configurations respectively. These values are obtained with an air flow of 0.023 kg/s and introducing a sample of experimental weather data collected in Algiers site for a sunny day in summer.

  6. Quality stability and sensory attributes of apple juice processed by thermosonication, pulsed electric field and thermal processing.

    Science.gov (United States)

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm

    2017-04-01

    Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices' antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.

  7. Convective Heat Transfer Coefficients of Automatic Transmission Fluid Jets with Implications for Electric Machine Thermal Management: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bennion, Kevin; Moreno, Gilberto

    2015-09-29

    Thermal management for electric machines (motors/ generators) is important as the automotive industry continues to transition to more electrically dominant vehicle propulsion systems. Cooling of the electric machine(s) in some electric vehicle traction drive applications is accomplished by impinging automatic transmission fluid (ATF) jets onto the machine's copper windings. In this study, we provide the results of experiments characterizing the thermal performance of ATF jets on surfaces representative of windings, using Ford's Mercon LV ATF. Experiments were carried out at various ATF temperatures and jet velocities to quantify the influence of these parameters on heat transfer coefficients. Fluid temperatures were varied from 50 degrees C to 90 degrees C to encompass potential operating temperatures within an automotive transaxle environment. The jet nozzle velocities were varied from 0.5 to 10 m/s. The experimental ATF heat transfer coefficient results provided in this report are a useful resource for understanding factors that influence the performance of ATF-based cooling systems for electric machines.

  8. Evaluation of electric and magnetic field monitoring of Miyake-jima volcano (Central Japan). 1995-1999

    Energy Technology Data Exchange (ETDEWEB)

    Sasai, Y.; Uyeshima, M.; Watanabe, H.; Takahashi, Y. [Tokyo Univ., Tokyo (Japan). Earthquake Research Institute; Zlotniki, J.; Yvetot, P. [Universite Blaise Pascal, Observatoire de Physique du Globe de Clermont-Ferrand, Clermont-Ferrand (France); Nishida, Y. [Hokkaido University, Graduate School of Science, Sapporo (Japan); Tanaka, Y. [Kyoto University, Graduate School of Science, Volcano Research Center (Japan)

    2001-04-01

    south around the central-southern area of the island from September 1996 to June 1998. The source of the anomaly, i.e. a thermally demagnetized area, was suggested to lie beneath the southern wall of Hatcho-Taira caldera. This is the first observation which indicates heating of the volcano besides the after-effects of the 1983 eruption. Except for the two locally anomalous stations, the geomagnetic total intensity on Miyake-jima island shows a gradual decrease for the past five years. This fact is probably related to the increasing pressure of the magma reservoir at depth as supported by the on-going inflation of the volcano via GPS observations.

  9. Thermal efficiency on welding of AA6061-T6 alloy by modified indirect electric arc and current signals digitalisation

    International Nuclear Information System (INIS)

    Ambriz, R. R.; Barrera, G.; Garcia, R.; Lopez, V. H.

    2009-01-01

    The results of the thermal efficiency on welding by modified indirect electric arc technique (MIEA) [1] of the 6061- T6 aluminum alloy are presented. These values are in a range of 90 to 94 %, which depend of the preheating employed. Thermal efficiency was obtained by means of a balance energy which considers the heat input, the amount of melted mass of the welding profiles, and welding parameters during the joining, especially of the arc current data acquisition. Also, some dimensionless parameters were employed in order to determine the approximation grade of the melted pool, the heat affected zone (HAZ), and their corresponding values with the experimental results. (Author) 13 refs

  10. Feeble magnetic fields generated by thermal charge fluctuations in extended metallic conductors: Implications for electric-dipole moment experiments

    International Nuclear Information System (INIS)

    Lamoreaux, S.K.

    1999-01-01

    A simple formulation for calculating the magnetic field external to an extended nonpermeable conducting body due to thermal current fluctuations within the body is developed, and is applied to a recent experimental search for the atomic electric-dipole moment (EDM) of 199 Hg. It is shown that the thermal fluctuation field is only slightly smaller in magnitude than other noise sources in that experiment. The formulation is extended to permeable bodies, and the implications for general EDM experiments are discussed. copyright 1999 The American Physical Society

  11. Effect of the type of metal on the electrical conductivity and thermal properties of metal complexes: The relation between ionic radius of metal complexes and electrical conductivity

    Science.gov (United States)

    Morgan, Sh. M.; El-Ghamaz, N. A.; Diab, M. A.

    2018-05-01

    Co(II) complexes (1-4) and Ni(II) complexes (5-8) were prepared and characterized by elemental analysis, IR spectra and thermal analysis data. Thermal decomposition of all complexes was discussed using thermogravimetric analysis. The dielectric properties and alternating current conductivity were investigated in the frequency range 0.1-100 kHz and temperature range 300-660 K. The thermal activation energies of electrical conductivity (ΔE1 and ΔE2) values for complexes were calculated and discussed. The values of ΔE1 and ΔE2 for complexes (1-8) were found to decrease with increasing the frequency. Ac electrical conductivity (σac) values increases with increasing temperatures and the values of σac for Co(II) complexes are greater than Ni(II) complexes. Co(II) complexes showed a higher conductivity than other Ni(II) complexes due to the higher crystallinity as confirmed by X-ray diffraction analysis.

  12. Electrically and thermally activated ageing mechanisms in metallised polymer film capacitors

    International Nuclear Information System (INIS)

    Lee, Yuen Pen

    2001-01-01

    This dissertation describes a combined computational and experimental study to understand the fundamental electrostatic, thermal, electromagnetic, and discharge related processes during the ageing of metallised polymer film capacitors. In the event of internal breakdowns, these capacitors are capable of 'self-healing' through a controlled isolation of defects on the electrode surfaces by mosaic patterning the electrode. The objective of this project is to develop viable computer models to unravel electrothermally activated ageing processes in capacitors. To provide the necessary validation to any capacitor models developed, our work is supported by comprehensive experiments including industrial standard accelerated life tests and associated breakdown damage analyses of tested capacitors. These have enabled an empirical identification of main factors affecting the reliability and lifetime of capacitors. Relevant raw data and the qualitative picture enabled by these data are crucial to the development and refinement of viable computational models of capacitors. Given the complexity of ageing processes, it is both very difficult and unnecessary to develop a one-for-all model that describes indiscriminately all relevant processes. The approach adapted in this work has been to prioritise key ageing processes and modularise each process with its own computer model. The overall picture of capacitor ageing can then be unravelled by integrating all modules together. For instance, the fine geometrical features of the electrode mosaic pattern and the capacitor's laminated structure have been assessed through a concept of field intensification using a 2D electrostatic finite element computation. With fine geometrical features accounted for by the field intensification concept, fast electric events in capacitors can be simulated using a simple equivalent circuit model. Similar assessment of heat transfer has led to an equally efficient modelling of thermal events in capacitors

  13. Thermal comfort optimisation of vernacular rural buildings: passive solutions to retrofit a typical farmhouse in central Italy

    Directory of Open Access Journals (Sweden)

    Maria Elena Menconi

    2017-06-01

    Full Text Available An adequate retrofitting of traditional rural buildings requires to preserve their formal characteristics and to understand the constructive elements that compose them and which are different in different geographical areas. This paper analyses the typical farmhouses in central Italy. Starting from the definition of a vernacular building model, the paper analyses its performance in terms of thermal comfort and energy efficiency. The methodology involves the use of energy dynamic simulations coupled with optimisation techniques aimed to identify the best combinations of insulating materials in terms of choice of material and its optimal location in the envelope. The paper demonstrates the good thermal and energy performance of farmhouses in central Italy. The results of the optimisation process showed that in these buildings, with the addition of insulation materials with low conductivity the perceived discomfort in the inhabited areas of the building can be reduced by 79% and the energy consumption related to heating can be reduced by 77%. The level of insulation of the pavement that separates the ground and first floor needs to be more moderate to promote the heat flow between floors during summer. The sensitivity analysis shows that the most influential component for thermal comfort is the roof insulation.

  14. Post-Metamorphic Thermal Anomaly across the Nacimiento Block, Central California: a Hydrothermal Overprint?

    Science.gov (United States)

    Lacroix, B.; Hughes, J.; Lahfid, A.; Delchini, S.

    2017-12-01

    The thermal history of the Nacimiento block located within the Franciscan Complex (California, USA) has been previously proposed based on both vitrinite reflectance (Rm) and illite cristallinity methods (Underwood et al., 1995). These authors suggest that the Nacimiento block is locally perturbed by a thermal anomaly (up to 300ºC), probably caused by post-metamorphic hydrothermal activity linked to the emplacement of an Au-deposit: the Los Burros Gold deposit. Although both thermal anomaly and deposit seem spatially correlated, their relationship is still poorly constrained. Detailed geological and structural mapping within the Los Burros Mining District (LBMD) coupled with a thermal study was conducted to better understand processes responsible for the anomalous temperatures recorded near the deposit. The regional maximum temperature reached by metasediments from the Nacimiento block have been first investigated using the Raman Spectroscopy of Carbonaceous Materials (RSCM) method. In addition, through careful fluid-inclusion and stable isotopes (O and C) studies on the deposit, the temperature and the potential source of the fluid responsible for the Los Burros Au-deposit emplacement were investigated. RSCM technique confirms the presence of a thermal anomaly in the range 260-320ºC near LBMD. However, our structural and petrographic results suggest that the thermal anomaly is not correlated to a post-metamorphic hydrothermal overprint but rather to a late, transpressive deformation uplifting buried metamorphic rocks.

  15. The thermal stability of magnetically exchange coupled MnBi/FeCo composites at electric motor working temperature

    Science.gov (United States)

    Cheng, Ye; Wang, Hongying; Li, Zhigang; Liu, Wanhui; Bao, Ilian

    2018-04-01

    The magnetically exchange coupled MnBi/FeCo composites were synthesized through a magnetic self-assembly process. The MnBi/FeCo composites were then hot pressed in a magnetic field to form magnets. The thermal stability of the magnets were tested by annealing at electric motor working temperature of 200 °C for 20, 40 and 60 h, respectively. It was found that after heating for 20 h, there was negligible change in its hysteresis loop. However, when the heating time was increased 40 and 60 h, the magnetic hysteresis loops presented two-phase magnetic behaviors, and the maximum energy products of the magnet were decreased. This research showed that the magnetically exchange coupled MnBi/FeCo composites had low thermal stability at electric motor working temperature.

  16. Employment of single-diode model to elucidate the variations in photovoltaic parameters under different electrical and thermal conditions.

    Directory of Open Access Journals (Sweden)

    Fahmi F Muhammad

    Full Text Available In this research work, numerical simulations are performed to correlate the photovoltaic parameters with various internal and external factors influencing the performance of solar cells. Single-diode modeling approach is utilized for this purpose and theoretical investigations are compared with the reported experimental evidences for organic and inorganic solar cells at various electrical and thermal conditions. Electrical parameters include parasitic resistances (Rs and Rp and ideality factor (n, while thermal parameters can be defined by the cells temperature (T. A comprehensive analysis concerning broad spectral variations in the short circuit current (Isc, open circuit voltage (Voc, fill factor (FF and efficiency (η is presented and discussed. It was generally concluded that there exists a good agreement between the simulated results and experimental findings. Nevertheless, the controversial consequence of temperature impact on the performance of organic solar cells necessitates the development of a complementary model which is capable of well simulating the temperature impact on these devices performance.

  17. Micro- and Nano-Scale Electrically Driven Two-Phase Thermal Management

    Science.gov (United States)

    Didion, Jeffrey R.

    2016-01-01

    This presentation discusses ground based proof of concept hardware under development at NASA GSFC to address high heat flux thermal management in silicon substrates. The goal is to develop proof of concept hardware for space flight validation. The space flight hardware will provide gravity insensitive thermal management for electronics applications such as transmit receive modules that are severely limited by thermal concerns.

  18. An effect of heat insulation parameters on thermal losses of water-cooled roofs for secondary steelmaking electric arc furnaces

    Directory of Open Access Journals (Sweden)

    E. Mihailov

    2016-07-01

    Full Text Available The aim of this work is research in the insulation parameters effect on the thermal losses of watercooled roofs for secondary steelmaking electric arc furnaces. An analytical method has been used for the investigation in heat transfer conditions in the working area. The results of the research can be used to choose optimal cooling parameters and select a suitable kind of insulation for water-cooled surfaces.

  19. Sizing of the thermal and electrical systems for an FED bundle divertor design with MgO insulation

    International Nuclear Information System (INIS)

    Schultz, J.H.

    1981-01-01

    The high-order dependence of toroidal ripple from a bundle divertor on the magnet shield thickness increases the desirability of a magnet technology with minimal shielding requirements. A jacketed conductor with MgO powder insulation has been used successfully in highly irradiated environments. Its properties and limitations are described. A thermal and electrical sizing code has been developed for magnet design with this technology. Two design examples for ETF and FED missions show reduced recirculating power from previously reported designs

  20. Market role, profitability and competitive features of thermal power plants in the Swedish future electricity market with high renewable integration

    OpenAIRE

    Llovera Bonmatí, Albert

    2017-01-01

    The Swedish energy market is currently undergoing a transition from fossil fuels to renewable energy sources, including a potential phase-out of nuclear power. The combination of a phase-out with expansion of intermittent renewable energy leads to the issue of increased fluctuations in electricity production. Energy-related organizations and institutions are projecting future Swedish energy scenarios with different possible transition pathways. In this study the market role of thermal power p...

  1. Spectroscopic, thermal, and electrical properties of MgO/ polyvinyl pyrrolidone/ polyvinyl alcohol nanocomposites

    Science.gov (United States)

    Mohammed, Gh.; El Sayed, Adel M.; Morsi, W. M.

    2018-04-01

    In this study, we aimed to control the optical and electrical properties of polyvinyl alcohol (PVA) in order to broaden its industrial and technological applications, which we achieved by blending PVA with polyvinyl pyrrolidone (PVP) and adding sol-gel prepared MgO nanopowder. The blended film and nanocomposite films were prepared using the solution casting technique. X-ray diffraction analyses showed that the crystallite size was ∼18.4 nm for MgO and the highest degree of crystallinity (XC) in the films was about 24.34% at 1.0 wt% MgO. High resolution transmission electron microscopy determined the nanoribbon morphology of MgO. Scanning electron microscopy (SEM) indicated the uniform distribution of the MgO nanoribbons on the surfaces of the PVA/PVP films. SEM and Fourier transform infrared spectroscopy also confirmed the interaction between the blend and MgO fillers. The effects of the additives on the glass transition (Tg) and melting (Tm) temperatures were evaluated by differential thermal analysis and differential scanning calorimetry. The appearance of one melting point confirmed the miscibility of the two polymers. According to ultraviolet-visible-near infrared spectroscopy measurements, the optical properties and optical constants of PVA could be adjusted by the addition of PVP and MgO, where the optical band gap (Eg) determined for PVA increased with the PVP content, whereas it decreased to 4.8 eV as the MgO content increased. The DC conductivity (σdc) of the films increased whereas the activation energy (Ea) decreased after the addition of MgO, possibly because the nanoribbon shape fixed the preferred conducting pathways. In addition, MgO could break the H-bond in sbnd OH groups of the blends to allow the free movement of the molecular chains.

  2. Electrical and thermal modeling of a large-format lithium titanate oxide battery system.

    Science.gov (United States)

    2015-04-01

    The future of mass transportation is clearly moving towards the increased efficiency of hybrid and electric vehicles. Electrical : energy storage is a key component in most of these advanced vehicles, with the system complexity and vehicle cost shift...

  3. Investigation of thermal energy transport from an anisotropic central heating element to the adjacent channels: A multipoint flux approximation

    KAUST Repository

    Salama, Amgad

    2015-02-01

    The problem of heat transfer from a central heating element pressed between two clad plates to cooling channels adjacent and outboard of the plates is investigated numerically. The aim of this work is to highlight the role of thermal conductivity anisotropy of the heating element and/or the encompassing plates on thermal energy transport to the fluid passing through the two channels. When the medium is anisotropic with respect to thermal conductivity; energy transport to the neighboring channels is no longer symmetric. This asymmetry in energy fluxes influence heat transfer to the coolant resulting in different patterns of temperature fields. In particular, it is found that the temperature fields are skewed towards the principal direction of anisotropy. In addition, the heat flux distributions along the edges of the heating element are also different as a manifestation of thermal conductivity anisotropy. Furthermore, the peak temperature at the channel walls change location and magnitude depending on the principal direction of anisotropy. Based on scaling arguments, it is found that, the ratio of width to the height of the heating system is a key parameter which can suggest when one may ignore the effect of the cross-diagonal terms of the full conductivity tensor. To account for anisotropy in thermal conductivity, the method of multipoint flux approximation (MPFA) is employed. Using this technique, it is possible to find a finite difference stencil which can handle full thermal conductivity tensor and in the same time enjoys the simplicity of finite difference approximation. Although the finite difference stencil based on MPFA is quite complex, in this work we apply the recently introduced experimenting field approach which construct the global problem automatically.

  4. Refined Three-Dimensional Modelling of Thermally-Driven Flow in the Bormio System (Central Italian Alps)

    Science.gov (United States)

    Volpi, Giorgio; Riva, Federico; Frattini, Paolo; Battista Crosta, Giovanni; Magri, Fabien

    2016-04-01

    Thermal springs are widespread in the European Alps, where more than 80 geothermal sites are known and exploited. The quantitative assessment of those thermal flow systems is a challenging issue and requires accurate conceptual model and a thorough understanding of thermo-hydraulic properties of the aquifers. Accordingly in the last years, several qualitative studies were carried out to understand the heat and fluid transport processes driving deep fluids from the reservoir to the springs. Our work focused on thermal circulation and fluid outflows of the area around Bormio (Central Italian Alps), where nine geothermal springs discharge from dolomite bodies located close to a regional alpine thrust, called the Zebrù Line. At this site, water is heated in deep circulation systems and vigorously upwells at temperature of about 40°C. The aim of this paper is to explore the mechanisms of heat and fluid transport in the Bormio area by carrying out refined steady and transient three-dimensional finite element simulations of thermally-driven flow and to quantitatively assess the source area of the thermal waters. The full regional model (ca. 700 km2) is discretized with a highly refined triangular finite element planar grid obtained with Midas GTS NX software. The structural 3D features of the regional Zebrù thrust are built by interpolating series of geological cross sections using Fracman. A script was developed to convert and implement the thrust grid into FEFLOW mesh that comprises ca. 4 million elements. The numerical results support the observed discharge rates and temperature field within the simulated domain. Flow and temperature patterns suggest that thermal groundwater flows through a deep system crossing both sedimentary and metamorphic lithotypes, and a fracture network associated to the thrust system. Besides providing a numerical framework to simulate complex fractured systems, this example gives insights into the influence of deep alpine structures on

  5. High thermal efficiency and low emission performance of a methanol reformed gas fueled engine for hybrid electric vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, K.; Nakajima, Y.; Shudo, T.; Hiruma, M. [Musahi Inst. of Tech., Tokyo (Japan); Komatsu, H.; Takagi, Y. [Nissan Motor Co., Ltd., Yokosuka (Japan)

    2000-07-01

    An internal combustion engine (ICE) operation was carried out experimentally by using the mixture of air and fuel simulating the reformed gas as the fuel. It has been found that the engine can expectedly attain ultra-low emission and high thermal efficiency, namely 35% brake thermal efficiency in the basis of the low heat value of the theoretically reformed gas or 42% in the basis of the low heat value of methanol. By using the result for the estimation of the total thermal efficiency at the end of the motor output shaft of a hybrid electric vehicle, it has been found that the total thermal efficiency of the reformed gas engine system is 34% in case of a 120% energy increment and 33% in case of a 116% energy increment with a little higher NOx emission of 60 ppm while the counterpart of the fuel cell system is 34%. When the emission level for EZEV is required, the total thermal efficiency falls to 32% in case of a 120% energy increment and 31% in case of a 116% energy increment. From the points of the reliability proved by the long history, higher specific power and low cost, the internal combustion engine system with the thermal efficiency almost equal to that of the fuel cell (FC) system is further more practical when methanol is used as the fuel. (orig.)

  6. Thermal Responses of Growth and Toxin Production in Four Prorocentrum Species from the Central Red Sea

    KAUST Repository

    Aynousah, Arwa

    2017-01-01

    Prorocentrum strains isolated from the Central Red Sea, Saudi Arabia. Morphological and molecular phylogenetic analysis identified the strains as P. elegans, P. rhathymum and P. emarginatum. However, the identity of strain P. sp.6 is currently unresolved

  7. Numerical study on optical and electric-thermal performance for solar concentrating PV/T air system

    Institute of Scientific and Technical Information of China (English)

    SUN Jian; SHI MingHeng

    2009-01-01

    Hybrid photovoltaic/thermsl(PV/T)system with solar concentrator is an effective way to improve solar energy conversion efficiency.In this work,a single-pass PV/T sir system with a three-trough compound parabolic concentrator(CPC)of concentration ratio 2.0 is designed and the solar incident distributions at the solar cell surface are calculated by ray tracing method.Based on energy balance,the heat transfer models of all main components in this system are developed.The effects of some main designing and operational parameters on the electric-thermal performance of the system are analyzed.The results show that the solar radiation intensity can be higher than 1200 W/m~2 at most area of the cell surface.The temperature of the air and cell surface increases along the length of the system.Thus the system efficiency of the CPC is higher than that of the system without the CPC.The thermal efficiency,exergy and electrical efficiency of this CPC system increase with increasing of the air mass flow rate and the length of the system.With increasing packing fraction the electrical efficiency increases,but the thermal efficiency decreases.The exergy efficiency increases slightly with the packing fraction rising.The data obtained in this work are valuable for the design and operation for this kind of solar concentrating PV/T systems.

  8. Thermal and Electrical Characterization of a Semi-Transparent Dye-Sensitized Photovoltaic Module under Real Operating Conditions

    Directory of Open Access Journals (Sweden)

    Cristina Cornaro

    2018-01-01

    Full Text Available Dye-sensitized solar cell technology is having an important role in renewable energy research due to its features and low-cost manufacturing processes. Devices based on this technology appear very well suited for integration into glazing systems due to their characteristics of transparency, color tuning and manufacturing directly on glass substrates. Field data of thermal and electrical characteristics of dye-sensitized solar modules (DSM are important since they can be used as input of building simulation models for the evaluation of their energy saving potential when integrated into buildings. However, still few studies in the literature provide this information. The study presented here aims to contribute to fill this lack providing a thermal and electrical characterization of a DSM in real operating conditions using a method developed in house. This method uses experimental data coming from test boxes exposed outdoor and dynamic simulation to provide thermal transmittance (U-value and solar heat gain coefficient (SHGC of a DSM prototype. The device exhibits a U-value of 3.6 W/m2·K, confirmed by an additional measurement carried on in the lab using a heat flux meter, and a SHGC of 0.2, value compliant with literature results. Electrical characterization shows an increase of module power with respect to temperature resulting DSM being suitable for integration in building facades.

  9. High thermal performance lithium-ion battery pack including hybrid active–passive thermal management system for using in hybrid/electric vehicles

    International Nuclear Information System (INIS)

    Fathabadi, Hassan

    2014-01-01

    In this study, a novel Li-ion battery pack design including hybrid active–passive thermal management system is presented. The battery pack is suitable for using in hybrid/electric vehicles. Active part of the hybrid thermal management system uses distributed thin ducts, air flow and natural convection as cooling media while the passive part utilizes phase change material/expanded graphite composite (PCM/EG) as cooling/heating component to optimize the thermal performance of the proposed battery pack. High melting enthalpy of PCM/EG composite together with melting of PCM/EG composite at the temperature of 58.9 °C remains the temperature distribution of the battery units in the desired temperature range (below 60 °C). The temperature and voltage distributions in the proposed battery pack design consisting of battery units, distributed thin ducts and PCM/EG composite are calculated by numerical solving of the related partial differential equations. Simulation results obtained by writing M-files code in Matlab environment and plotting the numerical data are presented to validate the theoretical results. A comparison between the thermal and physical characteristics of the proposed battery pack and other latest works is presented that explicitly proves the battery pack performance. - Highlights: • Novel Li-ion battery pack including active and passive thermal management systems. • The battery pack has high thermal performance for ambient temperatures until 55 °C. • Uniform temperature and voltage distributions. • The maximum observed temperature in each battery unit is less than other works. • The maximum temperature dispersion in each battery is less than other works

  10. Biochemical degradation and physical migration of polyphenolic compounds in osmotic dehydrated blueberries with pulsed electric field and thermal pretreatments.

    Science.gov (United States)

    Yu, Yuanshan; Jin, Tony Z; Fan, Xuetong; Wu, Jijun

    2018-01-15

    Fresh blueberries were pretreated by pulsed electric fields (PEF) or thermal pretreatment and then were subject to osmotic dehydration. The changes in contents of anthocyanins, predominantly phenolic acids and flavonols, total phenolics, polyphenol oxidase (PPO) activity and antioxidant activity in the blueberry samples during pretreatment and osmotic dehydration were investigated. Biochemical degradation and physical migration of these nutritive compounds from fruits to osmotic solutions were observed during the pretreatments and osmotic dehydration. PEF pretreated samples had the least degradation loss but the most migration loss of these compounds compared to thermally pretreated and control samples. Higher rates of water loss and solid gain during osmotic dehydration were also obtained by PEF pretreatment, reducing the dehydration time from 130 to 48h. PEF pretreated and dehydrated fruits showed superior appearance to thermally pretreated and control samples. Therefore, PEF pretreatment is a preferred technology that balances nutritive quality, appearance, and dehydration rate. Published by Elsevier Ltd.

  11. Manufacturing cost analysis of a parabolic dish concentrator (General Electric design) for solar thermal electric power systems in selected production volumes

    Science.gov (United States)

    1981-01-01

    The manufacturing cost of a General Electric 12 meter diameter concentrator was estimated. This parabolic dish concentrator for solar thermal system was costed in annual production volumes of 100 - 1,000 - 5,000 - 10,000 - 50,000 100,000 - 400,000 and 1,000,000 units. Presented for each volume are the costs of direct labor, material, burden, tooling, capital equipment and buildings. Also presented is the direct labor personnel and factory space requirements. All costs are based on early 1981 economics.

  12. Polystyrene-Poly(methyl methacrylate) Silver Nanocomposites: Significant Modification of the Thermal and Electrical Properties by Microwave Irradiation.

    Science.gov (United States)

    Alsharaeh, Edreese H

    2016-06-13

    This work compares the preparation of nanocomposites of polystyrene (PS), poly(methyl methacrylate) (PMMA), and PSMMA co-polymer containing silver nanoparticles (AgNPs) using in situ bulk polymerization with and without microwave irradiation (MWI). The AgNPs prepared were embedded within the polymer matrix. A modification in the thermal stability of the PS/Ag, PMMA/Ag, and PSMMA/Ag nanocomposites using MWI and in situ was observed compared with that of neat PSMMA, PS, and PMMA. In particular, PS/Ag, and PSMMA/Ag nanocomposites used in situ showed better thermal stability than MWI, while PMMA/Ag nanocomposites showed improved thermal stability. The electrical conductivity of the PS/Ag, PMMA/Ag, and PSMMA/Ag composites prepared by MWI revealed a percolation behavior when 20% AgNPs were used as a filler, and the conductivity of the nanocomposites increased to 103 S/cm, 33 S/cm, and 40 mS/cm, respectively. This enhancement might be due to the good dispersion of the AgNPs within the polymer matrix, which increased the interfacial interaction between the polymer and AgNPs. The polymer/Ag nanocomposites developed with tunable thermal and electrical properties could be used as conductive materials for electronic device applications.

  13. Effect of Surfactants and Manufacturing Methods on the Electrical and Thermal Conductivity of Carbon Nanotube/Silicone Composites

    Directory of Open Access Journals (Sweden)

    Martina Hřibová

    2012-11-01

    Full Text Available The effect of ionic surfactants and manufacturing methods on the separation and distribution of multi-wall carbon nanotubes (CNTs in a silicone matrix are investigated. The CNTs are dispersed in an aqueous solution of the anionic surfactant dodecylbenzene sulfonic acid (DBSA, the cationic surfactant cetyltrimethylammonium bromide (CTAB, and in a DBSA/CTAB surfactant mixture. Four types of CNT-based composites of various concentrations from 0 to 6 vol.% are prepared by simple mechanical mixing and sonication. The morphology, electrical and thermal conductivity of the CNT-based composites are analyzed. The incorporation of both neat and modified CNTs leads to an increase in electrical and thermal conductivity. The dependence of DC conductivity versus CNT concentration shows percolation behaviour with a percolation threshold of about 2 vol.% in composites with neat CNT. The modification of CNTs by DBSA increases the percolation threshold to 4 vol.% due to the isolation/separation of individual CNTs. This, in turn, results in a significant decrease in the complex permittivity of CNT–DBSA-based composites. In contrast to the percolation behaviour of DC conductivity, the concentration dependence of thermal conductivity exhibits a linear dependence, the thermal conductivity of composites with modified CNTs being lower than that of composites with neat CNTs. All these results provide evidence that the modification of CNTs by DBSA followed by sonication allows one to produce composites with high homogeneity.

  14. Effect of surfactants and manufacturing methods on the electrical and thermal conductivity of carbon nanotube/silicone composites.

    Science.gov (United States)

    Vilčáková, Jarmila; Moučka, Robert; Svoboda, Petr; Ilčíková, Markéta; Kazantseva, Natalia; Hřibová, Martina; Mičušík, Matej; Omastová, Mária

    2012-11-05

    The effect of ionic surfactants and manufacturing methods on the separation and distribution of multi-wall carbon nanotubes (CNTs) in a silicone matrix are investigated. The CNTs are dispersed in an aqueous solution of the anionic surfactant dodecylbenzene sulfonic acid (DBSA), the cationic surfactant cetyltrimethylammonium bromide (CTAB), and in a DBSA/CTAB surfactant mixture. Four types of CNT-based composites of various concentrations from 0 to 6 vol.% are prepared by simple mechanical mixing and sonication. The morphology, electrical and thermal conductivity of the CNT-based composites are analyzed. The incorporation of both neat and modified CNTs leads to an increase in electrical and thermal conductivity. The dependence of DC conductivity versus CNT concentration shows percolation behaviour with a percolation threshold of about 2 vol.% in composites with neat CNT. The modification of CNTs by DBSA increases the percolation threshold to 4 vol.% due to the isolation/separation of individual CNTs. This, in turn, results in a significant decrease in the complex permittivity of CNT–DBSA-based composites. In contrast to the percolation behaviour of DC conductivity, the concentration dependence of thermal conductivity exhibits a linear dependence, the thermal conductivity of composites with modified CNTs being lower than that of composites with neat CNTs. All these results provide evidence that the modification of CNTs by DBSA followed by sonication allows one to produce composites with high homogeneity.

  15. Prediction of thermal behaviors of an air-cooled lithium-ion battery system for hybrid electric vehicles

    Science.gov (United States)

    Choi, Yong Seok; Kang, Dal Mo

    2014-12-01

    Thermal management has been one of the major issues in developing a lithium-ion (Li-ion) hybrid electric vehicle (HEV) battery system since the Li-ion battery is vulnerable to excessive heat load under abnormal or severe operational conditions. In this work, in order to design a suitable thermal management system, a simple modeling methodology describing thermal behavior of an air-cooled Li-ion battery system was proposed from vehicle components designer's point of view. A proposed mathematical model was constructed based on the battery's electrical and mechanical properties. Also, validation test results for the Li-ion battery system were presented. A pulse current duty and an adjusted US06 current cycle for a two-mode HEV system were used to validate the accuracy of the model prediction. Results showed that the present model can give good estimations for simulating convective heat transfer cooling during battery operation. The developed thermal model is useful in structuring the flow system and determining the appropriate cooling capacity for a specified design prerequisite of the battery system.

  16. Many-body theory of electrical, thermal and optical response of molecular heterojunctions

    Science.gov (United States)

    Bergfield, Justin Phillip

    In this work, we develop a many-body theory of electronic transport through single molecule junctions based on nonequilibrium Green's functions (NEGFs). The central quantity of this theory is the Coulomb self-energy matrix of the junction SigmaC. SigmaC is evaluated exactly in the sequential-tunneling limit, and the correction due to finite lead-molecule tunneling is evaluated using a conserving approximation based on diagrammatic perturbation theory on the Keldysh contour. In this way, tunneling processes are included to infinite order, meaning that any approximation utilized is a truncation in the physical processes considered rather than in the order of those processes. Our theory reproduces the key features of both the Coulomb blockade and coherent transport regimes simultaneously in a single unified theory. Nonperturbative effects of intramolecular correlations are included, which are necessary to accurately describe the highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gap, essential for a quantitative theory of transport. This work covers four major topics related to transport in single-molecule junctions. First, we use our many-body theory to calculate the nonlinear electrical response of the archetypal Au-1,4-benzenedithiol-Au junction and find irregularly shaped 'molecular diamonds' which have been experimentally observed in some larger molecules but which are inaccessible to existing theoretical approaches. Next, we extend our theory to include heat transport and develop an exact expression for the heat current in an interacting nanostructure. Using this result, we discover that quantum coherence can strongly enhance the thermoelectric response of a device, a result with a number of technological applications. We then develop the formalism to include multi-orbital lead-molecule contacts and multi-channel leads, both of which strongly affect the observable transport. Lastly, we include a dynamic screening correction to

  17. A One-year, Short-Stay Crewed Mars Mission Using Bimodal Nuclear Thermal Electric Propulsion (BNTEP) - A Preliminary Assessment

    Science.gov (United States)

    Burke, Laura A.; Borowski, Stanley K.; McCurdy, David R.; Packard, Thomas W.

    2013-01-01

    A crewed mission to Mars poses a signi cant challenge in dealing with the physiolog- ical issues that arise with the crew being exposed to a near zero-gravity environment as well as signi cant solar and galactic radiation for such a long duration. While long sur- face stay missions exceeding 500 days are the ultimate goal for human Mars exploration, short round trip, short surface stay missions could be an important intermediate step that would allow NASA to demonstrate technology as well as study the physiological e ects on the crew. However, for a 1-year round trip mission, the outbound and inbound hy- perbolic velocity at Earth and Mars can be very large resulting in a signi cant propellant requirement for a high thrust system like Nuclear Thermal Propulsion (NTP). Similarly, a low thrust Nuclear Electric Propulsion (NEP) system requires high electrical power lev- els (10 megawatts electric (MWe) or more), plus advanced power conversion technology to achieve the lower speci c mass values needed for such a mission. A Bimodal Nuclear Thermal Electric Propulsion (BNTEP) system is examined here that uses three high thrust Bimodal Nuclear Thermal Rocket (BNTR) engines allowing short departure and capture maneuvers. The engines also generate electrical power that drives a low thrust Electric Propulsion (EP) system used for ecient interplanetary transit. This combined system can help reduce the total launch mass, system and operational requirements that would otherwise be required for equivalent NEP or Solar Electric Propulsion (SEP) mission. The BNTEP system is a hybrid propulsion concept where the BNTR reactors operate in two separate modes. During high-thrust mode operation, each BNTR provides 10's of kilo- Newtons of thrust at reasonably high speci c impulse (Isp) of 900 seconds for impulsive trans-planetary injection and orbital insertion maneuvers. When in power generation / EP mode, the BNTR reactors are coupled to a Brayton power conversion system allowing each

  18. A Combined Optical, Thermal and Electrical Performance Study of a V-Trough PV System—Experimental and Analytical Investigations

    Directory of Open Access Journals (Sweden)

    Haitham M. Bahaidarah

    2015-04-01

    Full Text Available The objective of this study was to achieve higher efficiency of a PV system while reducing of the cost of energy generation. Concentration photovoltaics was employed in the present case as it uses low cost reflectors to enhance the efficiency of the PV system and simultaneously reduces the cost of electricity generation. For this purpose a V-trough integrated with the PV system was employed for low concentration photovoltaic (LCPV. Since the electrical output of the concentrating PV system is significantly affected by the temperature of the PV cells, the motivation of the research also included studying the ability to actively cool PV cells to achieve the maximum benefit. The optical, thermal and electrical performance of the V-trough PV system was theoretically modeled and validated with experimental results. Optical modeling of V-trough was carried out to estimate the amount of enhanced absorbed radiation. Due to increase in the absorbed radiation the module temperature was also increased which was predicted by thermal model. Active cooling techniques were studied and the effect of cooling was analyzed on the performance of V-trough PV system. With absorbed radiation and module temperature as input parameters, electrical modeling was carried out and the maximum power was estimated. For the V-trough PV system, experiments were performed for validating the numerical models and very good agreement was found between the two.

  19. Electrical conductivity of the thermal dusty plasma under the conditions of a hybrid plasma environment simulation facility

    Science.gov (United States)

    Zhukhovitskii, Dmitry I.; Petrov, Oleg F.; Hyde, Truell W.; Herdrich, Georg; Laufer, Rene; Dropmann, Michael; Matthews, Lorin S.

    2015-05-01

    We discuss the inductively heated plasma generator (IPG) facility in application to the generation of the thermal dusty plasma formed by the positively charged dust particles and the electrons emitted by them. We develop a theoretical model for the calculation of plasma electrical conductivity under typical conditions of the IPG. We show that the electrical conductivity of dusty plasma is defined by collisions with the neutral gas molecules and by the electron number density. The latter is calculated in the approximations of an ideal and strongly coupled particle system and in the regime of weak and strong screening of the particle charge. The maximum attainable electron number density and corresponding maximum plasma electrical conductivity prove to be independent of the particle emissivity. Analysis of available experiments is performed, in particular, of our recent experiment with plasma formed by the combustion products of a propane-air mixture and the CeO2 particles injected into it. A good correlation between the theory and experimental data points to the adequacy of our approach. Our main conclusion is that a level of the electrical conductivity due to the thermal ionization of the dust particles is sufficiently high to compete with that of the potassium-doped plasmas.

  20. Tuning of the Seebeck Coefficient and the Electrical and Thermal Conductivity of Hybrid Materials Based on Polypyrrole and Bismuth Nanowires.

    Science.gov (United States)

    Hnida, Katarzyna E; Pilarczyk, Kacper; Knutelski, Marcin; Marzec, Mateusz; Gajewska, Marta; Kosonowski, Artur; Chlebda, Damian; Lis, Bartłomiej; Przybylski, Marek

    2018-04-06

    The growing demand for clean energy catalyzes the development of new devices capable of generating electricity from renewable energy resources. One of the possible approaches focuses on the use of thermoelectric materials (TE), which may utilize waste heat, water, and solar thermal energy to generate electrical power. An improvement of the performance of such devices may be achieved through the development of composites made of an organic matrix filled with nanostructured thermoelectric materials working in a synergetic way. The first step towards such designs requires a better understanding of the fundamental interactions between available materials. In this paper, this matter is investigated and the questions regarding the change of electrical and thermal properties of nanocomposites based on low-conductive polypyrrole enriched with bismuth nanowires of well-defined geometry and morphology is answered. It is clearly demonstrated that the electrical conductivity and the Seebeck coefficient may be tuned either simultaneously or separately within particular Bi NWs content ranges, and that both parameters may be increased at the same time. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Liquid-phase exfoliated graphene self-assembled films: Low-frequency noise and thermal-electric characterization

    International Nuclear Information System (INIS)

    Tubon Usca, G.; Hernandez-Ambato, J.; Pace, C.; Caputi, L.S.; Tavolaro, A.

    2016-01-01

    Highlights: • Graphene was exfoliated in liquid phase also in the presence of zeolite 4A. • Films were obtained by drop-casting. • SEM, Raman, low-frequency noise and thermal electric measurements show that the presence of zeolite improves the quality of the FLG films. - Abstract: In few years, graphene has become a revolutionary material, leading not only to applications in various fields such as electronics, medicine and environment, but also to the production of new types of 2D materials. In this work, Liquid Phase Exfoliation (LPE) was applied to natural graphite by brief sonication or mixer treatment in suitable solvents, in order to produce Few Layers Graphene (FLG) suspensions. Additionally, zeolite 4A (Z4A) was added during the production of FLG flakes-based inks, with the aim of aiding the exfoliation process. Conductive films were obtained by drop casting three types of suspensions over Al 2 O 3 substrates with interdigitated electrodes, with total channel surface of 1.39 mm 2 . The morphology characterization resulted in the verification of the presence of thin self-assembled flakes. Raman studies gave evidence of 4 to 10 layers graphene flakes. Electrical measurements were performed to state the Low-Frequency Noise and Thermal-Electric characteristics of the samples. We observe interesting relations between sample preparation procedures and electrical properties.

  2. Thermal analysis of wood of the main tree species of Central Siberia

    Directory of Open Access Journals (Sweden)

    S. R. Loskutov

    2015-12-01

    Full Text Available Thermal decomposition of wood from coniferous and deciduous species of Siberia has been studied using thermogravimetry (TG and differential scanning calorimetry (DSC. The tree species were larch Larix sibirica Ledeb., Scots pine Pinus sylvestris L., spruce Picea obovata Ledeb., fir Abies sibirica Ledeb., Siberian pine Pinus sibirica Du Tour., birch Betula pendula Roth., and aspen Populus tremula L. Thermal analysis of wood samples was carried out under oxidative (air and inert (argon atmospheres from 25 to 700 °С at heating rates 10, 20, 40 °С • min–1 (TG/DTG and from 25 to 590 °С at heating rates 10, 40 °С • min–1 (DSC. The stages of thermal decomposition, the temperature intervals, the mass loss, the mass loss rate, the temperature of DTG/DSC peaks, and heating effects were determined for each tree species. The kinetic thermal degradation parameters of wood were obtained by the Broido and Ozawa–Flynn–Wall models. The wood of coniferous and deciduous species of Siberia was characterized on the base of analysis of activation energy values at various stages of thermal decomposition and the relations of activation energy on conversion level of wood substance of different tree species, and also the comparison of mass loss at the same stages of thermal destruction, heating effects, residual mass and other parameters of TG/DTG, DSC. In our opinion, the results of this work present interest for researchers and specialists in the field of forest pyrology, wood science, dendrochemistry.

  3. Future distributed generation: An operational multi-objective optimization model for integrated small scale urban electrical, thermal and gas grids

    International Nuclear Information System (INIS)

    Lo Cascio, Ermanno; Borelli, Davide; Devia, Francesco; Schenone, Corrado

    2017-01-01

    Highlights: • Multi-objective optimization model for retrofitted and integrated natural gas pressure regulation stations. • Comparison of different incentive mechanisms for recovered energy based on the characteristics of preheating process. • Control strategies comparison: performances achieved with optimal control vs. ones obtained by thermal load tracking. - Abstract: A multi-objective optimization model for urban integrated electrical, thermal and gas grids is presented. The main system consists of a retrofitted natural gas pressure regulation station where a turbo-expander allows to recover energy from the process. Here, the natural gas must be preheated in order to avoid methane hydrates. The preheating phase could be based on fossil fuels, renewable or on a thermal mix. Depending on the system configuration, the proposed optimization model enables a proper differentiation based on how the natural gas preheating process is expected to be accomplished. This differentiation is addressed by weighting the electricity produced by the turbo-expander and linking it to proper remuneration tariffs. The effectiveness of the model has been tested on an existing plant located in the city of Genoa. Here, the thermal energy is provided by means of two redundant gas-fired boilers and a cogeneration unit. Furthermore, the whole system is thermally integrated with a district heating network. Numerical simulation results, obtained with the commercial proprietary software Honeywell UniSim Design Suite, have been compared with the optimal solutions achieved. The effectiveness of the model, in terms of economic and environmental performances, is finally quantified. For specific conditions, the model allows achieving an operational costs reduction of about 17% with the respect to thermal-load-tracking control logic.

  4. A Simplified Top-Oil Temperature Model for Transformers Based on the Pathway of Energy Transfer Concept and the Thermal-Electrical Analogy

    Directory of Open Access Journals (Sweden)

    Muhammad Hakirin Roslan

    2017-11-01

    Full Text Available This paper presents an alternative approach to determine the simplified top-oil temperature (TOT based on the pathway of energy transfer and thermal-electrical analogy concepts. The main contribution of this study is the redefinition of the nonlinear thermal resistance based on these concepts. An alternative approximation of convection coefficient, h, based on heat transfer theory was proposed which eliminated the requirement of viscosity. In addition, the lumped capacitance method was applied to the thermal-electrical analogy to derive the TOT thermal equivalent equation in differential form. The TOT thermal model was evaluated based on the measured TOT of seven transformers with either oil natural air natural (ONAN or oil natural air forced (ONAF cooling modes obtained from temperature rise tests. In addition, the performance of the TOT thermal model was tested on step-loading of a transformer with an ONAF cooling mode obtained from previous studies. A comparison between the TOT thermal model and the existing TOT Thermal-Electrical, Exponential (IEC 60076-7, and Clause 7 (IEEE C57.91-1995 models was also carried out. It was found that the measured TOT of seven transformers are well represented by the TOT thermal model where the highest maximum and root mean square (RMS errors are 6.66 °C and 2.76 °C, respectively. Based on the maximum and RMS errors, the TOT thermal model performs better than Exponential and Clause 7 models and it is comparable with the Thermal-Electrical 1 (TE1 and Thermal-Electrical 2 (TE2 models. The same pattern is found for the TOT thermal model under step-loading where the maximum and RMS errors are 5.77 °C and 2.02 °C.

  5. Planning Future Electric Vehicle Central Charging Stations Connected to Low-Voltage Distribution Networks

    DEFF Research Database (Denmark)

    Marra, Francesco; Træholt, Chresten; Larsen, Esben

    2012-01-01

    A great interest is recently paid to Electric Vehicles (EV) and their integration into electricity grids. EV can potentially play an important role in power system operation, however, the EV charging infrastructures have been only partly defined, considering them as limited to individual charging...... on their investment cost. Investigation on location and size of CCS is conducted, analyzing two LV grids of different capacity. The results enlighten that a public CCS should be preferably located in the range of 100 m from the transformer. The AC charging levels of 11 kW and 22 kW have the highest potential in LV...

  6. Mid-term evaluation of the NRECA (National Rural Electric Cooperative Association) Central America Rural Electrification Support Program (CARES)

    Energy Technology Data Exchange (ETDEWEB)

    Perlack, R.D. (Oak Ridge National Lab., TN (USA)); Jones, H.G. (Oak Ridge Associated Universities, Inc., TN (USA)); Garcia, A. III (Texas A and M Univ., College Station, TX (USA). Dept. of Agricultural Engineering); Flores, E. (Flores (Edgar), Guatemala City (Guatemala))

    1990-09-01

    Oak Ridge National Laboratory was requested by the Regional Office for Central America and Panama to conduct a mid-term evaluation of the Cares Project, which is being implemented by the National Rural Electric Cooperative Association. This evaluation was conducted over a three week period by a four person team. Overall, the project has had numerous successes and is highly valued by local counterpart utilities and USAID Missions. Notwithstanding the significant results of the project, changes can be made in certain operating procedures and in the direction of some programmatic activities that can lead to an even more effective project.

  7. Centralised electricity production from winter cereals biomass grown under central-northern Spain conditions: Global warming and energy yield assessments

    International Nuclear Information System (INIS)

    Sastre, C.M.; Maletta, E.; González-Arechavala, Y.; Ciria, P.; Santos, A.M.; Val, A. del; Pérez, P.; Carrasco, J.

    2014-01-01

    Highlights: • We assess the sustainability of electricity production from winter cereals biomass. • Productivity ranks are generated from different genotypes cultivated in real farms. • GHG and energy balances show better performance compared to natural gas electricity. • Cereals yields below 8 odt/ha do not accomplish objective 60% of GHG savings. • Marginal yields and sustainability criteria are discussed suggesting optimization. - Abstract: The goal of this paper is to assess the sustainability of electricity production from winter cereals grown in one of the most important Spanish agricultural areas, Castilla y León Region, situated in central-northern Spain. This study analyses greenhouse gases (GHG) emissions and energy balances of electricity production in a 25 MWe power plant that was powered using straw biomass from three annual winter cereals (rye, triticale and oat) grown as dedicated energy crops. The results of these analyses were compared with those of electricity produced from natural gas in Spanish power plants. Assessments were performed using a wide range of scenarios, mainly based on the biomass yield variability obtained in demonstration plots of twelve different winter cereal genotypes. Demonstration plots were established in two different locations (provinces of Soria and León) of the Castilla y León Region during two crop seasons (2009/2010 and 2010/2011) using common management practices and input rates for rain-fed agriculture in these regions. Our results suggest that production of electricity from winter cereals biomass combustion yielded considerable reductions in terms of GHG emissions when compared to electricity from natural gas. Nevertheless, the results show that low biomass yields that are relatively frequent for Spanish farmers on low productivity lands may produce no significant reductions in GHG in comparison with electricity from natural gas. Consequently, the agronomic management of winter cereals should be re

  8. Three-Dimensional Graphene Foam Induces Multifunctionality in Epoxy Nanocomposites by Simultaneous Improvement in Mechanical, Thermal, and Electrical Properties.

    Science.gov (United States)

    Embrey, Leslie; Nautiyal, Pranjal; Loganathan, Archana; Idowu, Adeyinka; Boesl, Benjamin; Agarwal, Arvind

    2017-11-15

    Three-dimensional (3D) macroporous graphene foam based multifunctional epoxy composites are developed in this study. Facile dip-coating and mold-casting techniques are employed to engineer microstructures with tailorable thermal, mechanical, and electrical properties. These processing techniques allow capillarity-induced equilibrium filling of graphene foam branches, creating epoxy/graphene interfaces with minimal separation. Addition of 2 wt % graphene foam enhances the glass transition temperature of epoxy from 106 to 162 °C, improving the thermal stability of the polymer composite. Graphene foam aids in load-bearing, increasing the ultimate tensile strength by 12% by merely 0.13 wt % graphene foam in an epoxy matrix. Digital image correlation (DIC) analysis revealed that the graphene foam cells restrict and confine the deformation of the polymer matrix, thereby enhancing the load-bearing capability of the composite. Addition of 0.6 wt % graphene foam also enhances the flexural strength of the pure epoxy by 10%. A 3D network of graphene branches is found to suppress and deflect the cracks, arresting mechanical failure. Dynamic mechanical analysis (DMA) of the composites demonstrated their vibration damping capability, as the loss tangent (tan δ) jumps from 0.1 for the pure epoxy to 0.24 for ∼2 wt % graphene foam-epoxy composite. Graphene foam branches also provide seamless pathways for electron transfer, which induces electrical conductivity exceeding 450 S/m in an otherwise insulator epoxy matrix. The epoxy-graphene foam composite exhibits a gauge factor as high as 4.1, which is twice the typical gauge factor for the most common metals. Simultaneous improvement in thermal, mechanical, and electrical properties of epoxy due to 3D graphene foam makes epoxy-graphene foam composite a promising lightweight and multifunctional material for aiding load-bearing, electrical transport, and motion sensing in aerospace, automotive, robotics, and smart device structures.

  9. Electricity

    CERN Document Server

    Basford, Leslie

    2013-01-01

    Electricity Made Simple covers the fundamental principles underlying every aspect of electricity. The book discusses current; resistance including its measurement, Kirchhoff's laws, and resistors; electroheat, electromagnetics and electrochemistry; and the motor and generator effects of electromagnetic forces. The text also describes alternating current, circuits and inductors, alternating current circuits, and a.c. generators and motors. Other methods of generating electromagnetic forces are also considered. The book is useful for electrical engineering students.

  10. Validating a centralized approach to primary frequency control with series-produced electric vehicles

    DEFF Research Database (Denmark)

    Marinelli, Mattia; Martinenas, Sergejus; Knezovic, Katarina

    2016-01-01

    , three Nissan Leaf, are not taking advantage of any V2G capability, but rely solely on the possibility of limiting the charge between 6 A and 16 A. The centralized approach implies that the frequency is not measured locally as it is a common practice today, but is routed via the Internet in order...

  11. Assessment of generic solar thermal systems for large power applications: analysis of electric power generating costs for systems larger than 10 MWe

    Energy Technology Data Exchange (ETDEWEB)

    Apley, W.J.; Bird, S.P.; Brown, D.R.; Drost, M.K.; Fort, J.A.; Garrett-Price, B.A.; Patton, W.P.; Williams, T.A.

    1980-11-01

    Seven generic types of collectors, together with associated subsystems for electric power generation, were considered. The collectors can be classified into three categories: (1) two-axis tracking (with compound-curvature reflecting surfaces); (2) one-axis tracking (with single-curvature reflecting surfaces); and (3) nontracking (with low-concentration reflecting surfaces). All seven collectors were analyzed in conceptual system configurations with Rankine-cycle engines. In addition, two of the collectors were analyzed with Brayton-cycle engines, and one was analyzed with a Stirling-cycle engine. With these engine options, and the consideration of both thermal and electrical storage for the Brayton-cycle central receiver, 11 systems were formulated for analysis. Conceptual designs developed for the 11 systems were based on common assumptions of available technology in the 1990 to 2000 time frame. No attempt was made to perform a detailed optimization of each conceptual design. Rather, designs best suited for a comparative evaluation of the concepts were formulated. Costs were estimated on the basis of identical assumptions, ground rules, methodologies, and unit costs of materials and labor applied uniformly to all of the concepts. The computer code SOLSTEP was used to analyze the thermodynamic performance characteristics and energy costs of the 11 concepts. Year-long simulations were performed using meteorological and insolation data for Barstow, California. Results for each concept include levelized energy costs and capacity factors for various combinations of storage capacity and collector field size.

  12. Electric machinery and drives in thermal power stations. Elektrische Maschinen und Antriebe in thermischen Kraftwerken

    Energy Technology Data Exchange (ETDEWEB)

    1974-01-01

    The following subjects were dealt with during the VDE meeting: 1) Requirements made by the electric network on the generators and their excitation equipment, and the influence thereof on their design; 2) requirements made by the power station process on the electric drives and the influence thereof on type and design; 3) requirements made on protective measures from the point of the electric power station machinery.

  13. Electron thermal transport barrier and magnetohydrodynamic activity observed in Tokamak plasmas with negative central shear

    NARCIS (Netherlands)

    M.R. de Baar,; Hogeweij, G. M. D.; Cardozo, N. J. L.; Oomens, A. A. M.; Schüller, F. C.

    1997-01-01

    In the Rijnhuizen Tokamak Project, plasmas with steady-state negative central shear (NCS) are made with off-axis electron cyclotron heating. Shifting the power deposition by 2 mm results in a sharp transition of confinement. The good confinement branch features a transport barrier at the off-axis

  14. Improved cooler design of electric arc furnace refractory in mining industry using thermal analysis modeling and simulation

    International Nuclear Information System (INIS)

    Istadi, I.; Bindar, Y.

    2014-01-01

    Production of steel and nickel using the electric arc furnace should be focused on the intensification of energy. Improvement of energy efficiency of the most consuming facilities was achieved by improving the use of alternative energy minimization such as reducing the heat lost of hot gases, minimizing the heat radiated through refractory linings of metallurgical furnaces, and cooling the highly thermally stressed components. The refractory of electric arc furnace should be modified to achieve the best cooling system of the furnace. In this physical modeling and simulation works, four modification scenarios of wall refractory designs were simulated, i.e. refractory with basic design, refractory with deep plate coolers, refractory with extra plate coolers, and refractory with wall falling film coolers. Finally, the use of deep plate cooler and the existing waffle cooler system was considered to be the best design of efficient electric arc furnace operationally. - Highlights: • Electric arc furnace design should be focused on the intensification of energy. • Refractory of electric arc furnace were modified to achieve the best cooling system. • Four modification scenarios of the wall refractory designs were simulated. • Use of deep plate cooler and existing waffle cooler system is the best cooling

  15. Analysis of electrical and thermal stress effects on PCBM:P3HT solar cells by photocurrent and impedance spectroscopy modeling

    DEFF Research Database (Denmark)

    Torto, Lorenzo; Rizzo, Antonio; Cester, Andrea

    2017-01-01

    We investigated the effects of electrical stress and thermal storage by means of photocurrent, Impedance Spectroscopy and Open Circuit Voltage Decay models. The electrical stress damages only the active layer, by reducing the generation rate, the polaron separation probability and the carrier...... lifetime. The thermal stress also degrades the anode interface. This reflects on the appearance of an inflection in the I-V photocurrent shape close to the operative region....

  16. Electrically and Thermally Conductive Low Density Polyethylene-Based Nanocomposites Reinforced by MWCNT or Hybrid MWCNT/Graphene Nanoplatelets with Improved Thermo-Oxidative Stability

    OpenAIRE

    Sandra Paszkiewicz; Anna Szymczyk; Daria Pawlikowska; Jan Subocz; Marek Zenker; Roman Masztak

    2018-01-01

    In this paper, the electrical and thermal conductivity and morphological behavior of low density polyethylene (LDPE)/multi-walled carbon nanotubes (MWCNTs) + graphene nanoplatelets (GNPs) hybrid nanocomposites (HNCs) have been studied. The distribution of MWCNTs and the hybrid of MWCNTs/GNPs within the polymer matrix has been investigated with scanning electron microscopy (SEM). The results showed that the thermal and electrical conductivity of the LDPE-based nanocomposites increased along wi...

  17. Remote-Activated Electrical Stimulation via Piezoelectric Scaffold System for Functional Peripheral and Central Nerve Regeneration

    OpenAIRE

    Low, Karen Gail

    2017-01-01

    A lack of therapeutic technologies that enable electrically stimulating nervous tissues in a facile and clinically relevant manner has partly hindered the advancement in treating nerve injuries for full functional recovery. Currently, the gold standard for nerve repair is autologous nerve grafting. However, this method has several disadvantages, such as necessity for multiple surgeries, creation of functionally impaired region where graft was taken from, disproportion of graft to nerve tissue...

  18. Risk and cost comparison of energy technologies for central electric power generation

    International Nuclear Information System (INIS)

    Sterrett, D.H.

    1980-01-01

    An evaluation of nuclear energy as it relates to alternative sources of electric power generation is presented. Citing Duke Power Company's Oconee Nuclear Station, the nuclear option in the past was the obvious choice. Today it is still the preferred alternative both economically and because of increasing environmental concerns over other energy alternatives. Public acceptance of nuclear generation, following Three Mile Island, remains a significant hurdle in its path

  19. Choice between hierarchy and market: Case of Central Electricity Generating Board's reorganization

    International Nuclear Information System (INIS)

    Caroli, M.

    1992-01-01

    Through the use of the 'Organization and Market' theoretical approach, this article outlines CEGB's reorganization to evaluate this experience under the strategic planning and operating effectiveness perspectives. The first part synthesizes the basic points of the 1990 reform which divided CEGB into three different companies and separated the control of the generation of electric power from its transport. The second part summarizes the main considerations about conditions of efficiency of vertical integration and disintegration, according to the 'Organization and Market' approach. By utilizing the conclusions highlighted in the first two parts of this article, the third one studies the effects of CEGB's vertical disintegration on the level of competition in power generation market; on CEGB's strategic effectiveness and operative efficiency; and on transactional costs in the electric power industry. CEGB's reorganization does not seem to have had a relevantly positive effect on competition, while it has caused a strategic burden and a significant increase of transactional costs in the exchange of electricity between the generator and the transmitter

  20. Modelling Thermal Effects of Battery Cells inside Electric Vehicle Battery Packs

    DEFF Research Database (Denmark)

    Khan, Mohammad Rezwan; Kær, Søren Knudsen

    The poster presents a methodology to account for thermal effects on battery cells to improve the typical thermal performances in a pack through heating calculations generally performed under the operating condition assumption. The aim is to analyze the issues based on battery thermo-physical char...

  1. SUPER-CAPACITOR APPLICATION IN ELECTRICAL POWER CABLE TESTING FACILITIES IN THERMAL ENDURANCE AND MECHANICAL BRACING TESTS

    Directory of Open Access Journals (Sweden)

    I. V. Oleksyuk

    2015-01-01

    Full Text Available The current-carrying cores of the electrical power cables should be resistant to effects of short-circuit currents whose values depend on the material of the core, its cross-sectional area, cable insulation properties, environment temperature, and the duration of the short-circuit current flow (1 and 3–4 sec. when tested for thermal endurance and mechanical bracing. The facilities for testing the 10 kV aluminum core cables with short-circuit current shall provide mechanical-bracing current 56,82 kA and thermal endurance current 11,16 kA. Although capacitors provide such values of the testing currents to the best advantage, utilizing conventional capacitor-units will involve large expenditures for erecting and  running a separate building. It is expedient to apply super-capacitors qua the electric power supply for testing facilities, as they are capacitors with double-electrical layer and involve the current values of tens of kilo-amperes.The insulation voltage during short-circuit current testing being not-standardized, it is not banned to apply voltages less than 10 kV when performing short-circuit thermal endurance and mechanical bracing tests for electrical power cables of 10 kV. The super-capacitor voltage variation-in-time graph consists of two regions: capacitive and resistive. The capacitive part corresponds to the voltage change consequent on the energy change in the super-capacitors. The resistive part shows the voltage variation due to the active resistance presence in the super-capacitor.The author offers the algorithm determining the number of super capacitors requisite for testing 10 kV-electrical power cables with short-circuit currents for thermal endurance and mechanical bracing. The paper shows that installation of super-capacitors in the facilities testing the cables with short-circuit currents reduces the area needed for the super-capacitors in comparison with conventional capacitors more than by one order of magnitude.

  2. Operational Constraints on Hydropeaking and its Effects on the Hydrologic and Thermal Regime of a River in Central Chile

    Science.gov (United States)

    Olivares, M. A.; Guzman, C.; Rossel, V.; De La Fuente, A.

    2013-12-01

    Hydropower accounts for about 44% of installed capacity in Chile's Central Interconnected System, which serves most of the Chilean population. Hydropower reservoir projects can affect ecosystems by changing the hydrologic regime and water quality. Given its volumen regulation capacity, low operation costs and fast response to demand fluctuations, reservoir hydropower plants commonly operate on a load-following or hydropeaking scheme. This short-term operational pattern produces alterations in the hydrologic regime downstream the reservoir. In the case of thermally stratified reservoirs, peaking operations can affect the thermal structure of the reservoir, as well as the thermal regime downstream. In this study, we assessed the subdaily hydrologic and thermal alteration donwstream of Rapel reservoir in Central Chile for alternative operational scenarios, including a base case and several scenarios involving minimum instream flow (Qmin) and maximum hourly ramping rates (ΔQmax). Scenarios were simulated for the stratification season of summer 2009-2012 in a grid-wide short-term economic dispatch model which prescribes hourly power production by every power plant on a weekly horizon. Power time series are then translated into time series of turbined flows at each hydropower plants. Indicators of subdaily hydrologic alteration (SDHA) were computed for every scenario. Additionally, turbined flows were used as input data for a three-dimensional hydrodynamic model (CWR-ELCOM) of the reservoir which simulated the vertical temperature profile in the reservoir and the outflow temperature. For the time series of outflow temperatures we computed several indicators of subdaily thermal alteration (SDTA). Operational constraints reduce the values of both SDHA and SDTA indicators with respect to the base case. When constraints are applied separately, the indicators of SDHA decrease as each type of constraint (Qmin or ΔQmax) becomes more stringent. However, ramping rate

  3. Optimal electricity dispatch on isolated mini-grids using a demand response strategy for thermal storage backup with genetic algorithms

    International Nuclear Information System (INIS)

    Neves, Diana; Silva, Carlos A.

    2015-01-01

    The present study uses the DHW (domestic hot water) electric backup from solar thermal systems to optimize the total electricity dispatch of an isolated mini-grid. The proposed approach estimates the hourly DHW load, and proposes and simulates different DR (demand response) strategies, from the supply side, to minimize the dispatch costs of an energy system. The case study consists on optimizing the electricity load, in a representative day with low solar radiation, in Corvo Island, Azores. The DHW backup is induced by three different demand patterns. The study compares different DR strategies: backup at demand (no strategy), pre-scheduled backup using two different imposed schedules, a strategy based on linear programming, and finally two strategies using genetic algorithms, with different formulations for DHW backup – one that assigns number of systems and another that assigns energy demand. It is concluded that pre-determined DR strategies may increase the generation costs, but DR strategies based on optimization algorithms are able to decrease generation costs. In particular, linear programming is the strategy that presents the lowest increase on dispatch costs, but the strategy based on genetic algorithms is the one that best minimizes both daily operation costs and total energy demand, of the system. - Highlights: • Integrated hourly model of DHW electric impact and electricity dispatch of isolated grid. • Proposal and comparison of different DR (demand response) strategies for DHW backup. • LP strategy presents 12% increase on total electric load, plus 5% on dispatch costs. • GA strategy presents 7% increase on total electric load, plus 8% on dispatch costs

  4. Electrical/thermal transport and electronic structure of the binary cobalt pnictides CoPn2 (Pn = As and Sb

    Directory of Open Access Journals (Sweden)

    Yosuke Goto

    2015-06-01

    Full Text Available We demonstrate the electrical and thermal transport properties of polycrystalline CoPn2 (Pn = As and Sb between 300 and 900 K. CoAs2 shows semiconducting electrical transport up to 900 K, while CoSb2 exhibits degenerate conduction. Sign inversion of the Seebeck coefficient is observed at ∼310 and ∼400 K for CoAs2 and CoSb2, respectively. Thermal conductivity at 300 K is 11.7 Wm−1K−1 for CoAs2 and 9.4 Wm−1K−1 for CoSb2. The thermoelectric power factor of CoAs2 is ∼10 μWcm−1K−2, although the dimensionless figure of merit is limited to ∼0.1 due to relatively high thermal conductivity. Using electronic structure calculations, the band gap value is calculated to be 0.55 eV for CoAs2 and 0.26 eV for CoSb2.

  5. Artificial Neural Network based control for PV/T panel to track optimum thermal and electrical power

    International Nuclear Information System (INIS)

    Ben Ammar, Majed; Chaabene, Maher; Chtourou, Zied

    2013-01-01

    Highlights: ► We establish a state model of PV/T panel. ► We study the effect of mass flow rate on PV/T efficiency. ► A real time PV/T control algorithm is proposed. ► A model based optimal thermal and electrical power operation point is tracked. - Abstract: As solar energy is intermittent, many algorithms and electronics have been developed to track the maximum power generation from photovoltaic and thermal panels. Following technological advances, these panels are gathered into one unit: PV/T system. PV/T delivers simultaneously two kinds of power: electrical power and thermal power. Nevertheless, no control systems have been developed in order to track maximum power generation from PV/T system. This paper suggests a PV/T control algorithm based on Artificial Neural Network (ANN) to detect the optimal power operating point (OPOP) by considering PV/T model behavior. The OPOP computes the optimum mass flow rate of PV/T for a considered irradiation and ambient temperature. Simulation results demonstrate great concordance between OPOP model based calculation and ANN outputs.

  6. A reliability design method for a lithium-ion battery pack considering the thermal disequilibrium in electric vehicles

    Science.gov (United States)

    Xia, Quan; Wang, Zili; Ren, Yi; Sun, Bo; Yang, Dezhen; Feng, Qiang

    2018-05-01

    With the rapid development of lithium-ion battery technology in the electric vehicle (EV) industry, the lifetime of the battery cell increases substantially; however, the reliability of the battery pack is still inadequate. Because of the complexity of the battery pack, a reliability design method for a lithium-ion battery pack considering the thermal disequilibrium is proposed in this paper based on cell redundancy. Based on this method, a three-dimensional electric-thermal-flow-coupled model, a stochastic degradation model of cells under field dynamic conditions and a multi-state system reliability model of a battery pack are established. The relationships between the multi-physics coupling model, the degradation model and the system reliability model are first constructed to analyze the reliability of the battery pack and followed by analysis examples with different redundancy strategies. By comparing the reliability of battery packs of different redundant cell numbers and configurations, several conclusions for the redundancy strategy are obtained. More notably, the reliability does not monotonically increase with the number of redundant cells for the thermal disequilibrium effects. In this work, the reliability of a 6 × 5 parallel-series configuration is the optimal system structure. In addition, the effect of the cell arrangement and cooling conditions are investigated.

  7. Electrochemical modeling and performance evaluation of a new ammonia-based battery thermal management system for electric and hybrid electric vehicles

    International Nuclear Information System (INIS)

    Al-Zareer, Maan; Dincer, Ibrahim; Rosen, Marc A.

    2017-01-01

    The operating temperatures of lithium ion battery packs in electrical vehicles and hybrid electrical vehicles need to be maintained in an optimum range for better performance and longer battery life. This paper proposes a new battery pack cooling system that utilizes the low saturation temperature of the fuel in ammonia based future hybrid electric vehicles. In the proposed cooling system, the batteries are partially submerged in to the liquid ammonia, and the liquid ammonia cools the battery by absorbing the heat and evaporating and the ammonia vapor cools the part of the battery not covered by liquid ammonia. The relationships between the performance of the battery cooling system and the maximum temperature (and the temperature distribution) in the battery are investigated for practical applications. The effect of the length of the battery that is submerged in to the liquid ammonia on the thermal performance of battery is studied and evaluated. The present results show that the proposed ammonia based cooling system offers a unique opportunity to maintain the operating temperature of the battery in an optimum range for consecutive charging and discharging phases at a high rate of 7.5C.

  8. A Novel Approach to Enhance the Mechanical Strength and Electrical and Thermal Conductivity of Cu-GNP Nanocomposites

    Science.gov (United States)

    Saboori, Abdollah; Pavese, Matteo; Badini, Claudio; Fino, Paolo

    2018-01-01

    Copper/graphene nanoplatelet (GNP) nanocomposites were produced by a wet mixing method followed by a classical powder metallurgy technique. A qualitative evaluation of the structure of graphene after mixing indicated that wet mixing is an appropriate dispersion method. Thereafter, the effects of two post-processing techniques such as repressing-annealing and hot isostatic pressing (HIP) on density, interfacial bonding, hardness, and thermal and electrical conductivity of the nanocomposites were analyzed. Density evaluations showed that the relative density of specimens increased after the post-processing steps so that after HIPing almost full densification was achieved. The Vickers hardness of specimens increased considerably after the post-processing techniques. The thermal conductivity of pure copper was very low in the case of the as-sintered samples containing 2 to 3 pct porosity and increased considerably to a maximum value in the case of HIPed samples which contained only 0.1 to 0.2 pct porosity. Electrical conductivity measurements showed that by increasing the graphene content electrical conductivity decreased.

  9. Electricity in lieu of nautral gas and oil for industrial thermal energy: a preliminary survey

    Energy Technology Data Exchange (ETDEWEB)

    Tallackson, J. R.

    1979-02-01

    In 1974, industrial processors accounted for nearly 50% of the nation's natural gas consumption and nearly 20% of its consumption of petroleum. This report is a preliminary assessment of the potential capability of the process industries to substitute utility-generated electricity for these scarce fuels. It is tacitly assumed that virtually all public utilities will soon be relying on coal or nuclear fission for primary energy. It was concluded that the existing technology will permit substitution of electricity for approximately 75% of the natural gas and petroleum now being consumed by industrial processors, which is equivalent to an annual usage of 800 million barrels of oil and 9 trillion cubic feet of gas at 1974 levels. Process steam generation, used throughout industry and representing 40% of its energy usage, offers the best near-term potential for conversion to electricity. Electric boilers and energy costs for steam are briefly discussed. Electrically driven heat pumps are considered as a possible method to save additional low-grade energy. Electrical reheating at high temperatures in the primary metals sector will be an effective way to conserve gas and oil. A wholesale shift by industry to electricity to replace gas and oil will produce impacts on the public utilities and, perhaps, those of a more general socio-economic nature. The principal bar to large-scale electrical substitution is economics, not technology. 174 references.

  10. The electric double layer put to work : thermal physics at electrochemical interfaces

    NARCIS (Netherlands)

    Janssen, M.A.

    2017-01-01

    Where charged electrode surfaces meet fluids that contain mobile ions, so-called electric double layers (EDLs) form to screen the electric surface charge by a diffuse cloud of counterionic charge in the fluid phase. This double layer has been studied for over a century and is of paramount importance

  11. Heat transfer and thermal management studies of lithium polymer batteries for electric vehicle applications

    Science.gov (United States)

    Song, Li

    The thermal conductivities of the polymer electrolyte and composite cathode are important parameters characterizing heat transport in lithium polymer batteries. The thermal conductivities of lithium polymer electrolytes, including poly-ethylene oxide (PEO), PEO-LiClO4, PEO-LiCF3SO 3, PEO-LiN(CF3SO2)2, PEO-LiC(CF 3SO2)3, and the thermal conductivities of TiS 2 and V6O13 composite cathodes, were measured over the temperature range from 25°C to 150°C by a guarded heat flow meter. The thermal conductivities of the electrolytes were found to be relatively constant for the temperature and for electrolytes with various concentrations of the lithium salt. The thermal conductivities of the composite cathodes were found to increase with the temperature below the melting temperature of the polymer electrolyte and only slightly increase above the melting temperature. Three different lithium polymer cells, including Li/PEO-LiCF3 S O3/TiS2, Li/PEO-LiC(CF3 S O2)3/V6 O13, and Li/PEO-LiN(CF3 S O2)2/ Li1+x Mn2 O4 were prepared and their discharge curves, along with heat generation rates, were measured at various galvanostatic discharge current densities, and at different temperature (70°C, 80°C and 90°C), by a potentiostat/galvanostat and an isothermal microcalorimeter. The thermal stability of a lithium polymer battery was examined by a linear perturbation analysis. In contrast to the thermal conductivity, the ionic conductivity of polymer electrolytes for lithium-polymer cell increases greatly with increasing temperature, an instability could arise from this temperature dependence. The numerical calculations, using a two dimensional thermal model, were carried out for constant potential drop across the electrolyte, for constant mean current density and for constant mean cell output power. The numerical calculations were approximately in agreement with the linear perturbation analysis. A coupled mathematical model, including electrochemical and thermal components, was

  12. Thermal impact of a small alas-valley river in a continuous permafrost area - insights and issues raised from a field monitoring Site in Syrdakh (Central Yakutia)

    Science.gov (United States)

    Grenier, Christophe; Nicolas, Roux; Fedorov, Alexander; Konstantinov, Pavel; Séjourné, Antoine; Costard, François; Marlin, Christelle; Khristoforov, Ivan; Saintenoy, Albane

    2017-04-01

    Lakes are probably the most prominent surface water bodies in continuous permafrost areas. As a consequence, they are also the most studied features in these regions (e.g. Fedorov et al. 2014). They are indeed of great interest, not only for local populations that use the water resource they represent both in winter and summer, but also from a climatic point of view as they can be a specific source of green-house gases due to the relatively warmer environment they create, especially associated with their taliks (thawed zone surrounded by permafrost located beneath large enough lakes). From a hydrogeological perspective, such taliks can form complex groundwater networks, thus possibly connecting sub-permafrost groundwater with surface water in the present context of climate change. On the other hand, rivers, another important feature of permafrost landscapes providing similar challenges, have drawn less attention so that only a few studies focus on river interactions with permafrost (e.g. Costard et al. 2014, Grenier et al. 2013). However, the processes of heat transfer at stake between river and permafrost strongly differ from lake systems for several reasons. The geometries differ, the river water flow and thermal regimes and interactions with the lateral slopes (valley) are specific. Of particular importance is the fact that the water, in the case of rivers, is in motion leading to specific heat exchange phenomena between water and soil. (Roux et al., accepted) addressed this issue recently by means of an experimental study in a cold room and associated numerical simulations. The present study focuses on a real river-permafrost system with its full natural complexity. A small alas-valley in the vicinity of Yakutsk (Central Yakutia, Siberia) was chosen. Monitoring was started in October 2012 to study the thermal and hydrological interactions between a river and its underground in this continuous permafrost environment. Thermal sensors were installed inside the

  13. Tactile, thermal, and electrical thresholds in patients with and without phantom limb pain after traumatic lower limb amputation

    Directory of Open Access Journals (Sweden)

    Li S

    2015-04-01

    Full Text Available Shengai Li,1,2 Danielle H Melton,1,2 Sheng Li1,2 1Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX, USA; 2Neurorehabilitation Research Laboratory, TIRR Memorial Hermann Research Center, Houston, TX, USA Purpose: To examine whether there is central sensitization in patients with phantom limb pain (PLP after traumatic limb amputation. Methods: Seventeen patients after unilateral lower limb amputation secondary to trauma were enrolled. Ten patients had chronic PLP, while the other seven patients had no PLP. Tactile-sensation threshold, cold- and warm-sensation thresholds, cold- and heat-pain thresholds, electrical-sensation threshold (EST, and electrical-pain threshold on the distal residual limb and the symmetrical site on the sound limb were measured in all tested patients. Their thresholds were compared within the PLP and non-PLP group, and between the groups. Results: The novel findings included: 1 electrical-pain threshold was only decreased in the sound limb in the PLP group and there was no difference between two limbs in the non-PLP group, suggesting central sensitization in patients with PLP; and 2 EST was increased on the affected limb as compared to the sound limb within the PLP group, but there were no significant differences in EST between the PLP and non-PLP group. There were in general no significant differences in other tested thresholds within the groups and between groups. Conclusion: Our results demonstrate central sensitization in the patients with PLP after traumatic limb amputation. Keywords: central sensitization, pain threshold, human

  14. Power in trust: the environmental history of the Central Electricity Generating Board

    International Nuclear Information System (INIS)

    Sheail, John

    1991-01-01

    The rapid and large-scale development of the electricity supply industry in the United Kingdom since the early years of the century has brought to the fore a large number of environmental issues. affecting the use of town and countryside, rivers and coastal waters, and the protection of amenity, wildlife, and out-door recreational interests. Few industries have experienced so much opposition. As the industry found to its cost, the basic attributes of land, air, and water are never so much cherished as when they are threatened by some novel form of development. Few enterprises have been so resourceful in responding to this public concern. Great importance has been attached to explaining development policies and technical options. Large programmes of research have been carried out. This is the first book to examine in depth the environmental issues that have arisen since the National Grid was first planned in the 1920s. The main focus is on the impact of power stations and the main transmission lines of England and Wales since the nationalization of the industry in 1947. Insights are provided into how issues were regarded at the time, and the manner in which they were tackled within the opportunities and constraints presented by advances in the use of coal, oil, hydro-electricity, and nuclear power. The story ends with the privatization of the industry under the Electricity Act of 1989. A distinctive feature of the book is the considerable use made of the archives of the industry itself, and of the Government departments and other bodies with which the industry had to work. Much of this material has not previously been published. (author)

  15. Intraoperative direct electrical stimulations of central nervous system during surgery of gliomas near eloquent areas

    Directory of Open Access Journals (Sweden)

    WANG Wei-min

    2012-12-01

    Full Text Available Objective To report our experiences of direct cortical stimulation in surgery of gliomas located in eloquent areas. Methods Clinical data of 157 patients with gliomas underwent awake craniotomy with the direct electrical stimulation for functional mapping of the eloquent areas were analysed retrospectively. Results Negative cortical stimulation was found in 4 patients, and positive cortical stimulation was achieved in 153 patients (97.45% . Four hundred and ninty -six cortical sites in 139 patients were detected for motor response by direct electrical stimulation, 70 sites in 21 patients for sensory, 112 sites in 91 patients for language (such as counting and naming. The positive areas of counting disturbance were mainly seen at the lower part of left precentral gyri operculum of left inferior frontal gyri, triangular part of left inferior frontal gyri, posterior part of left middle frontal gyri, and posterior part of left superior frontal gyri. Postoperative MRI showed 92 patients (58.60% achieved total resection, 55 cases (35.03% subtotal and 10 cases (6.37% partial. One hundred and ten patients (70.06% were diagnosed as having low grade glimas, including 71 cases of astrocytoma, 26 cases of oligodendroglioma, and 13 cases of mixed astro ? oligodendroglioma, 47 patients (29.94% were high grade gliomas, including 19 cases of glioblastoma, 15 cases of anaplastic astrocytoma, and 13 cases of anaplastic oligodendroglioma. After operation 53 patients (33.76% occurred transient postoperative paralysis, 39 patients (24.84% transient language disturbance and 4 patients (2.55% permanent neurological deficits. Conclusion Intraoperative direct electrical stimulation is a reliable, precise and safety method for functional mapping of the eloquent areas. This technique allows us to achieve 'maximal safety resection' in glioma surgery.

  16. Central unresolved issues in thermal energy storage for building heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Swet, C.J.; Baylin, F.

    1980-07-01

    This document explores the frontier of the rapidly expanding field of thermal energy storage, investigates unresolved issues, outlines research aimed at finding solutions, and suggests avenues meriting future research. Issues related to applications include value-based ranking of storage concepts, temperature constraints, consistency of assumptions, nomenclature and taxonomy, and screening criteria for materials. Issues related to technologies include assessing seasonal storage concepts, diurnal coolness storage, selection of hot-side storage concepts for cooling-only systems, phase-change storage in building materials, freeze protection for solar water heating systems, and justification of phase-change storage for active solar space heating.

  17. Status of human factors research program in Central Research Institute of Electric Power Industry

    International Nuclear Information System (INIS)

    Kabetani, Tetsuji

    1989-01-01

    The Human Factors Research Center was established within CRIEPI on July 1, 1987 as its research efforts to reduce human error during operation and maintenance at Japanese nuclear power plants. The Research Program has seven subjects, composed of the original subjects that include the human behavior monitoring method, and the subjects requested by the Federation of Electric Power Companies that include the establishment of techniques of analysing and evaluating information on human error. Some results of the activity are applied in nuclear power plants. We plan to obtain good results to apply to plants, and to improve the results already obtained. (author)

  18. Power's promise: electricity reforms in Eastern Europe and Central Asia, vol. 1

    Energy Technology Data Exchange (ETDEWEB)

    Lampietti, J. (ed.)

    2004-06-01

    This study analyzes the fiscal, efficiency, social, and environmental impact of power sector reforms in seven countries in the Europe and East Asia region - Armenia; Azerbaijan; Georgia; Hungary; Kazakhstan and POland. It finds sector deficits have been falling over the last decade and that the savings from lower sector deficits did not translate into higher social spending. More emphasis must be placed on monitoring deficits and tailoring policy reform to country specific circumstances. The impact of reform on utility efficiency, as measured by the cost of generation, system loss collections, and operational efficiency, is ambiguous. While overall revenue per kilowatt hour increased in almost all countries, problems continue with losses, collection rates, and staffing. In terms of social impacts, electricity spending as a share of income increased, especially for the poor, while consumption stayed the same. In terms of environmental impacts, reforms did slightly improve energy efficiency in power plants though this has little direct impact on human health because the electricity sector's share of the total health damage from air pollution is negligible. Several lessons emerge from the analysis. Undertaking simple ex ante simulations of reform impacts will allow better identification of potential reform benefits and costs. Placing more emphasis on outcome-based indicators of service quality would help ensure that future operations produce the intended end-user benefits. In many cases, tariff increases can and should be explicitly timed to coincide with service quality improvements. 24 figs., 15 tabs., 10 annexes.

  19. Solar thermal power plants for heat and electricity generation; Presentacion de plantas termosolares para generacion de calor y energia electrica

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Cajigal, V [Solartronic S. A. de C. V., Cuernavaca (Mexico); Manzini, F; Sanchez, A [Laboratorio de Energia Solar (IIM-UNAM), Temixco (Mexico)

    1993-12-31

    Solar thermal technology is presented for concentration into a point for the production of heat and energy in small and large scale, emphasis is made on the capacity for the combination with current technologies using fossil fuels for electricity generation and process steam, increasing the global efficiency of the power plants and notably reducing the pollutants emission to the air during the insolation hours. It is successfully compared with other solar-thermal technologies. [Espanol] Se presenta la tecnologia termosolar de concentracion puntual para produccion de calor y de energia en pequena y gran escala, se enfatiza su capacidad de combinacion con las tecnologias actuales que utilizan combustibles fosiles para produccion de electricidad y vapor de proceso, aumentando la eficiencia global de las plantas y reduciendo notablemente sus emisiones contaminantes a la atmosfera durante las horas de insolacion. Se le compara exitosamente con otras tecnologias termosolares.

  20. Heat conduction coefficient and coefficient of linear thermal expansion of electric insulation materials for superconducting magnetic system

    International Nuclear Information System (INIS)

    Deev, V.I.; Sobolev, V.P.; Kruglov, A.B.; Pridantsev, A.I.

    1984-01-01

    Results of experimental investigation of heat conduction coefficient and coefficient of linear thermal expansion and thermal shrinkages of the STEF-1 textolite-glass widely used in superconducting magnetic systems as electric insulating and structural material are presented. Samples of two types have been died: sample axisa is perpendicular to a plae of fiberglass layers ad sample axis is parallel to a plane of fiberglass layers. Heat conduction coefficient was decreased almost a five times with temperature decrease from 300 up to 5K and was slightly dependent on a sample type. Temperature variation of linear dimensions in a sample of the first type occurs in twice as fast as compared to the sample of the second type