WorldWideScience

Sample records for large thermal discharges

  1. Large-volume excitation of air, argon, nitrogen and combustible mixtures by thermal jets produced by nanosecond spark discharges

    Science.gov (United States)

    Stepanyan, Sergey; Hayashi, Jun; Salmon, Arthur; Stancu, Gabi D.; Laux, Christophe O.

    2017-04-01

    This work presents experimental observations of strong expanding thermal jets following the application of nanosecond spark discharges. These jets propagate in a toroidal shape perpendicular to the interelectrode axis, with high velocities of up to 30 m s-1 and over distances of the order of a cm. Their propagation length is much larger than the thermal expansion region produced by the conventional millisecond sparks used in car engine ignition, thus greatly improving the volumetric excitation of gas mixtures. The shape and velocity of the jets is found to be fairly insensitive to the shape of the electrodes. In addition, their spatial extent is found to increase with the number of nanosecond sparks and with the discharge voltage, and to decrease slightly with the pressure between 1 and 7 atm at constant applied voltage. Finally, this thermal jet phenomenon is observed in experiments conducted with many types of gas mixtures, including air, nitrogen, argon, and combustible CH4/air mixtures. This makes nanosecond repetitively pulsed discharges particularly attractive for aerodynamic flow control or plasma-assisted combustion because of their ability to excite large volumes of gas, typically about 100 times the volume of the discharge.

  2. Impact of thermal discharge on marine environment - an overview

    International Nuclear Information System (INIS)

    Murugesan, A.G.; Rameshwari, S.; Sukumaran, N.

    2002-01-01

    Thermal pollution has been used to indicate the detrimental effects of heated effluents discharged by power plants and other industries. It denotes the impairment of quality and deterioration of aquatic and terrestrial environment through heated effluent and fly ash. Various industrial plants like thermal, atomic, nuclear, coal fired plants, oil field generators, factories and mills utilize water for cooling purposes. In India, there are about 60 thermal power plants, which produce 30 million tonnes of fly ash every year. The heated effluents from power plants is discharged at a temperature, which is 8-10 degC higher than that of intake marine water. The adverse effect of thermal discharge are visible in microorganism, fish, biotic life and the over all ecosystems. The discharge of heated effluents actually affects the fish respiration, metabolism and other physiological activities of marine organisms, which ultimately leads to death. This could be due to synergism because of toxic chemical such as copper, nickel, chromium and chlorine, which are used to remove slimes in the pipelines. The major waste material from thermal power station is the fly ash that creates enormous pollution problem to air, water and soil environment. Fly ash possess large amounts of lead, cobalt, chromium, cadmium etc. When this fly ash is released out through water carriage system it leads to turbidity, over deposition and flood also. Tuticorin Thermal Power Station (TTPS) has installed five power generation units each of 250 MW capacities. About 1.35 lakhs m 3 /hr water is drawn from the sea, utilized for cooling and then the heated effluent is discharged into the same environment. Therefore, this paper deals with various impacts associated with thermal discharge on marine environment. (author)

  3. 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.

  4. Legal aspects of thermal discharges

    International Nuclear Information System (INIS)

    Martin, A.J.

    1974-01-01

    An overview of those legal areas which directly affect technical and planning decisions is presented in the form of 2 legal approaches which constrain the indiscriminate release of thermal discharges to receiving waters. One takes the form of private remedies which have traditionally been available to aggrieved parties who are in some way damaged by the harmful discharge. The 2nd approach utilizes the various statutory constraints leading to direct governmental action. It appears that statutory law is playing the prominent role in restricting the temperature to which receiving waters may be raised as a result of such discharges by using effluent limitations and water quality standards. (Water Resour. Abstr.)

  5. Thermal storage/discharge performances of Cu-Si alloy for solar thermochemical process

    Science.gov (United States)

    Gokon, Nobuyuki; Yamaguchi, Tomoya; Cho, Hyun-seok; Bellan, Selvan; Hatamachi, Tsuyoshi; Kodama, Tatsuya

    2017-06-01

    The present authors (Niigata University, Japan) have developed a tubular reactor system using novel "double-walled" reactor/receiver tubes with carbonate molten-salt thermal storage as a phase change material (PCM) for solar reforming of natural gas and with Al-Si alloy thermal storage as a PCM for solar air receiver to produce high-temperature air. For both of the cases, the high heat capacity and large latent heat (heat of solidification) of the PCM phase circumvents the rapid temperature change of the reactor/receiver tubes at high temperatures under variable and uncontinuous characteristics of solar radiation. In this study, we examined cyclic properties of thermal storage/discharge for Cu-Si alloy in air stream in order to evaluate a potentiality of Cu-Si alloy as a PCM thermal storage material. Temperature-increasing performances of Cu-Si alloy are measured during thermal storage (or heat-charge) mode and during cooling (or heat-discharge) mode. A oxidation state of the Cu-Si alloy after the cyclic reaction was evaluated by using electron probe micro analyzer (EPMA).

  6. Impacts of thermal and chemical discharges to surface water

    International Nuclear Information System (INIS)

    Stober, Q.J.

    1974-01-01

    Various aspects of thermal and chemical discharges to surface water are outlined. The major impacts of nuclear power plants on aquatic resources are disruption during construction, intake of cooling water, discharge problems, and interactions with other water users. The following topics are included under the heading, assessment of aquatic ecology: identification of flora and fauna; abundance of aquatic organisms; species-environment relationships; and identification of pre-existing environmental stress. The following topics are included under the heading, environmental effects of plant operation: entrapment of fish by cooling water; passage of plankton through cooling system; discharge area and thermal plume; chemical effluents; and plant construction. (U.S.)

  7. Thermal discharge residence by Lake Michigan Salmonids

    International Nuclear Information System (INIS)

    Romberg, G.P.; Prepejchal, W.

    1975-01-01

    Lake Michigan salmon and trout were tagged with a thermoluminescent dosimeter (TLD) temperature tag to estimate their thermal exposure and residence time at a warm water discharge. Fish were collected, tagged, and released at the Point Beach Nuclear Plant, Two Rivers, Wisconsin, in the fall of 1973 and 1974. Tags were recovered during the same season, primarily from fish recaptured at Point Beach. Average uniform temperature exposure and maximum possible discharge residence time were determined. Appropriate hourly intake and discharge temperatures were averaged to calculate mean temperature exposure for the case of maximum discharge residence. Lowest discharge temperature not included within the period of maximum residence was identified to serve as a possible indicator of avoidance temperature. Mean values for the above parameters were calculated for fish species for each tagging year and are reported with the accompanying range of intake and discharge temperatures

  8. Preliminary study on acceptability of scope of thermal discharge mixing zone for nuclear power plant

    International Nuclear Information System (INIS)

    Liu Yongye; Yang Yang; Wang Liang; Chen Xiaoqiu; Liu Senlin

    2012-01-01

    Based on the situation that the existing domestic temperature control standards are not performable, the preliminary study on the acceptability of the mixing zone scope of thermal discharge for nuclear power plant was conducted in this paper, taking a coastal power station SNP as a case. The following preliminary conclusions could be drawn from the results of cluster analysis of the SNP site under different results of mathematical modeling and physical model test: 1) The influence intensity of ecological function of the SNP site seawater is small and the scope of thermal discharge mixing zone is acceptable under SNP-1 (Unit 1 and 2) operating condition; 2) the influence intensity of ecological function of the SNP site seawater is small and the scope of thermal discharge mixing zone is acceptable in spring under SNP-1 (Unit 1 and 2) and SNP-2 (Unit 3 and 4) operating condition, while the influence intensity of ecological function of the SNP site seawater is large and the scope of mixing zone is unacceptable in autumn under the same operating condition. (authors)

  9. Implication of thermal discharges into the sea - A review

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumar, V.; Sastry, J.S.; Swamy, G.N.

    The adverse effects of thermal discharges into coastal waters from power plants have been reviewed. The direct and indirect impacts of thermal pollution to marine biota have been discussed briefly. The tolerance limits documented elsewhere have been...

  10. Detection of coastal and submarine discharge on the Florida Gulf Coast with an airborne thermal-infrared mapping system

    Science.gov (United States)

    Raabe, Ellen; Stonehouse, David; Ebersol, Kristin; Holland, Kathryn; Robbins, Lisa

    2011-01-01

    Along the Gulf Coast of Florida north of Tampa Bay lies a region characterized by an open marsh coast, low topographic gradient, water-bearing limestone, and scattered springs. The Floridan aquifer system is at or near land surface in this region, discharging water at a consistent 70-72°F. The thermal contrast between ambient water and aquifer discharge during winter months can be distinguished using airborne thermal-infrared imagery. An airborne thermal-infrared mapping system was used to collect imagery along 126 miles of the Gulf Coast from Jefferson to Levy County, FL, in March 2009. The imagery depicts a large number of discharge locations and associated warm-water plumes in ponds, creeks, rivers, and nearshore waters. A thermal contrast of 6°F or more was set as a conservative threshold for identifying sites, statistically significant at the 99% confidence interval. Almost 900 such coastal and submarine-discharge locations were detected, averaging seven to nine per mile along this section of coast. This represents approximately one hundred times the number of previously known discharge sites in the same area. Several known coastal springs in Taylor and Levy Counties were positively identified with the imagery and were used to estimate regional discharge equivalent to one 1st-order spring, discharging 100 cubic feet per second or more, for every two miles of coastline. The number of identified discharge sites is a conservative estimate and may represent two-thirds of existing features due to low groundwater levels at time of overflight. The role of aquifer discharge in coastal and estuarine health is indisputable; however, mapping and quantifying discharge in a complex karst environment can be an elusive goal. The results of this effort illustrate the effectiveness of the instrument and underscore the influence of coastal springs along this stretch of the Florida coast.

  11. 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

  12. Thermal effects on metabolic activities of thermophilic microorganisms from the thermal discharge point of Tuticorin thermal power plant area

    International Nuclear Information System (INIS)

    Muthukkannan, N.; Murugesan, A.G.

    2002-01-01

    Metabolic activities of thermophilic microorganisms isolated from the thermal water discharge point at Tuticorin thermal power station were studied by growing the microorganisms in sterile medium and at various temperature regimes of 25, 35, 45, 55 and 65degC. The optimum temperature for the growth of the bacterium isolated from the thermal power plant station was 45 degC and beyond 65 degC the growth was gradually decreased. The bacteria isolated from open sea water were mesophiles with their growth optimum at 35 degC and microbes inhabiting the thermal discharge area were thermopiles as they were tolerant even at 55 degC. The amylase production, carbohydrate metabolism and lactose fermentation activities were optimum at 45 degC. At 25 degC and beyond 65 degC biochemical activities of the organisms were inhibited to a greater extent. (author)

  13. Thermal modeling of cylindrical lithium ion battery during discharge cycle

    International Nuclear Information System (INIS)

    Jeon, Dong Hyup; Baek, Seung Man

    2011-01-01

    Highlights: → Transient and thermo-electric finite element analysis (FEA) of cylindrical lithium ion (Li-ion) battery was presented. → This model provides the thermal behavior of Li-ion battery during discharge cycle. → A LiCoO 2 /C battery at various discharge rates was investigated. → The contribution of heat source due to joule heating was significant at a high discharge rate. → The contribution of heat source due to entropy change was dominant at a low discharge rate. - Abstract: Transient and thermo-electric finite element analysis (FEA) of cylindrical lithium ion (Li-ion) battery was presented. The simplified model by adopting a cylindrical coordinate was employed. This model provides the thermal behavior of Li-ion battery during discharge cycle. The mathematical model solves conservation of energy considering heat generations due to both joule heating and entropy change. A LiCoO 2 /C battery at various discharge rates was investigated. The temperature profile from simulation had similar tendency with experiment. The temperature profile was decomposed with contributions of each heat sources and was presented at several discharge rates. It was found that the contribution of heat source due to joule heating was significant at a high discharge rate, whereas that due to entropy change was dominant at a low discharge rate. Also the effect of cooling condition and the LiNiCoMnO 2 /C battery were analyzed for the purpose of temperature reduction.

  14. Thermal mechanism of prepeak formation in Pulsed Glow Discharge

    Science.gov (United States)

    Voronov, Maxim; Hoffmann, Volker; Steingrobe, Tobias; Buscher, Wolfgang; Engelhard, Carsten; Storey, Andrew; Ray, Steven; Hieftje, Gary

    2012-10-01

    A microsecond Pulsed Glow Discharge (μs PGD) in a Grimm-type source is characterized by the so-called ``prepeak,'' which is a spike in both electrical current and emission intensity at the leading edge of the discharge pulse. The prepeak is followed by synchronized vibrations of the current and the emission. To understand the nature of these phenomena, a microphone was inserted into the discharge chamber. Acoustical waves were detected and found to be in correlation with the measured vibrations. This points to a thermal mechanism for prepeak formation: the gas is heated in the leading edge of the discharge pulse and then expanded. To prove this suggestion, a Monte-Carlo based model was developed to simulate the evolution of Ar concentration, temperature, and flow in time and space. Potentially, the model could be used for gas simulations in a wide range of different applications. Here, the model is incorporated into an existing but modified model of the μs PGD in a Grimm-type plasma excitation source. Results of the simulations confirm that the thermal mechanism is responsible for the formation of the electrical prepeak and the pressure waves.

  15. Numerical investigation of thermal behaviors in lithium-ion battery stack discharge

    International Nuclear Information System (INIS)

    Liu, Rui; Chen, Jixin; Xun, Jingzhi; Jiao, Kui; Du, Qing

    2014-01-01

    Highlights: • The thermal behaviors of a Li-ion battery stack have been investigated by modeling. • Parametric studies have been performed focusing on three different cooling materials. • Effects of discharge rate, ambient temperature and Reynolds number are examined. • General guidelines are proposed for the thermal management of a Li-ion battery stack. - Abstract: Thermal management is critically important to maintain the performance and prolong the lifetime of a lithium-ion (Li-ion) battery. In this paper, a two-dimensional and transient model has been developed for the thermal management of a 20-flat-plate-battery stack, followed by comprehensive numerical simulations to study the influences of ambient temperature, Reynolds number, and discharge rate on the temperature distribution in the stack with different cooling materials. The simulation results indicate that liquid cooling is generally more effective in reducing temperature compared to phase-change material, while the latter can lead to more homogeneous temperature distribution. Fast and deep discharge should be avoided, which generally yields high temperature beyond the acceptable range regardless of cooling materials. At low or even subzero ambient temperatures, air cooling is preferred over liquid cooling because heat needs to be retained rather than removed. Such difference becomes small when the ambient temperature increases to a mild level. The effects of Reynolds number are apparent in liquid cooling but negligible in air cooling. Choosing appropriate cooling material and strategy is particularly important in low ambient temperature and fast discharge cases. These findings improve the understanding of battery stack thermal behaviors and provide the general guidelines for thermal management system. The present model can also be used in developing control system to optimize battery stack thermal behaviors

  16. Treatment of hazardous wastes by DC thermal plasma arc discharge

    International Nuclear Information System (INIS)

    Toru, Iwao; Yafang, Liu; Furuta, N.; Tsuginori, Inaba

    2001-01-01

    The temperature of the DC thermal plasma arc discharge is discussed, and examples of the waste treatment for the inorganic compounds such as fly ash, asbestos, and for the organic compounds such as the toxic dioxines and TBT by using the DC plasma arc discharge are shown. In addition, the plasma treatment by using a radiant power emitted from the DC plasma arc discharge is also shown as another new kind of ones. (authors)

  17. A Study on infrared tracing and monitoring of thermal discharge from the power plants

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byung Sun; Hong, Wuk Hee; Kim, Yung Bae; Park, Jang Rae; Choi, Yung An; Park, Yung San [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center

    1996-08-01

    Massive discharge of cooling water from the nuclear power plants as well as many thermal power plants would cause serious environmental problems. Hence, the task of predicting cooling water dispersion areas has enormous importance for better environmental management related with the power plant operation. For the last two decades, extensive field survey and dispersion modeling have been mainly applied to predict thermal discharge dispersion areas. In this study, the method of infrared thermal sensing was tested as a possible means of measuring the affected areas of thermal discharge at the thermal power plant sites. Many IR images obtained by using the terrestrial camera, or by using the airborne scanner, or from the Landsat iv satellite were analyzed from the pc with the IDRISI and resource software and further enhanced with other image analysis technologies. The result of study proved this IR imaging technology to be an potentially cost-effective tool for assessment of water-temperature increase caused by the thermal discharge from the power plants, however, further elaboration of procedure was highly requested. (author). 9 refs., 24 figs.

  18. Constructive and thermal design of a core fast discharge

    International Nuclear Information System (INIS)

    Schroer, H.

    1979-08-01

    The present study is concerned with the development and thermal design of a fast discharge system for balls for the PR 3000 MWsub(th) process heat reactor. The term 'fast discharge system for balls' denotes a very short-time discharge procedure of the entire core contents, i.e. the flowing out of the fuel elements due to gravity into a receiver tank underneath the prestressed-concrete vessel. From a safety-engineering point of view, the fast discharge system for balls constitutes an additional possibility of active decay heat removal, besides the multiply redundant and diversitary reactor protection system, serving to further reduce the remaining residual risk. A fast discharge system for balls, however, is to be used only in the event of all the other possibilities of active decay heat removal having failed and when the maximum permissible temperatures for particularly exposed primary circuit components have been reached. However, the application range of such a system is restricted exclusively to high-temperature reactors with spherical fuel elements; the procedure cannot be applied to other reactor systems because of the rigidly fixed position of the fuel elements inside the core and for reasons of fuel element geometry. Besides the purpose of application, the influence of in-core temperature development on the possible actuation of the fast discharge system is being described in particular detail. This is followed by a description of the structural and thermal design of three specific major components, i.e. the piping system, shut-off devices and fuel element receiver tank, which will have to be installed additionally for the implementation of a fast discharge system for balls as compared to previous plant concepts. (orig.) [de

  19. Groundwater discharge mapping by thermal infra-red imagery

    International Nuclear Information System (INIS)

    Brereton, N.R.

    1984-02-01

    An area around Altnabreac in northern Scotland has been studied as part of the UK programme of research into the feasibility of disposal of radioactive waste into geological formations. An essential prerequisite to being able to predict the behaviour, migratory pathways and travel times of radionuclides emanating from a waste repository is an understanding of the regional and near surface groundwater flow systems and groundwater geochemical evolution. The groundwater system at depth has been studied by means of boreholes but an understanding of the shallow groundwater flow, and its interaction with groundwater upwelling from depth, can be gained from studies of the spatial distribution and geochemistry of surface springs and discharges. A survey was carried out using the thermal infra-red linescan technique with the objective of locating all significant spring discharges over the study area. The terrain around Altnabreac is largely covered by superficial deposits which overlie weathered granite. The survey was carried out from a height of 275m at a spatial resolution of about 0.5m. About 280 line Km were covered but allowing for overlap between adjacent flight lines and some repeat coverage, the actual area surveyed was 68 sq Km. The most striking aspect of the results is the wide distribution of groundwater discharges in the Altnabreac area. An analysis of the data identified three general categories of spring and many of these springs were subsequently visited for verification and to allow samples to be collected for chemical analysis. The results from this survey indicates that the groundwater table is strongly influenced by local topography and that the majority of the spring discharges represent near surface recent groundwaters circulating within the superficial deposits and weathered granite

  20. Biological effects from discharge of cooling water from thermal power plants

    International Nuclear Information System (INIS)

    1976-12-01

    Results are reported for a Danish project on biological effects from discharge of cooling water from thermal power plants. The purpose of the project was to provide an up-to-date knowledge of biological effects of cooling water discharge and of organization and evaluation of recipient investigations in planned and established areas. (BP)

  1. Environmental characterization to assess potential impacts of thermal discharge to the Columbia River

    International Nuclear Information System (INIS)

    Neitzel, D.A.; Dauble, D.D.; Page, T.L.; Greager, E.M.

    1990-01-01

    Laboratory and field studies were conducted to assess the potential impact of the N-Reactor thermal plume on fish from the Hanford Reach of the Columbia River. Discharge water temperatures were measured over a range of river flows and reactor operating conditions. Data were mathematically modeled to define spatial and thermal characteristics of the plume. Four species of Columbia River fish were exposed to thermal conditions expected in the plume. Exposed fish were subjected to predators and disease organisms to test for secondary effects from thermal stress. Spatial and temporal distribution of anadromous fish in the river near N-Reactor were also evaluated to define location relative to the plume. Potential thermal exposures were insufficient to kill or injure fish during operation of N-Reactor. These studies demonstrate that characterization of hydrological conditions and thermal tolerance can adequately assess potential impacts of a thermal discharge to fish

  2. Effect of thermal contact resistances on fast charging of large format lithium ion batteries

    International Nuclear Information System (INIS)

    Ye, Yonghuang; Saw, Lip Huat; Shi, Yixiang; Somasundaram, Karthik; Tay, Andrew A.O.

    2014-01-01

    Highlights: • The effect of thermal contact resistance on thermal performance of large format lithium ion batteries. • The effect of temperature gradient on electrochemical performance of large format batteries during fast charging. • The thermal performance of lithium ion battery utilizing pulse charging protocol. • Suggestions on battery geometry design optimization to improve thermal performance. - Abstract: A two dimensional electrochemical thermal model is developed on the cross-plane of a laminate stack plate pouch lithium ion battery to study the thermal performance of large format batteries. The effect of thermal contact resistance is taken into consideration, and is found to greatly increase the maximum temperature and temperature gradient of the battery. The resulting large temperature gradient would induce in-cell non-uniformity of charging-discharging current and state of health. Simply increasing the cooling intensity is inadequate to reduce the maximum temperature and narrow down the temperature difference due to the poor cross-plane thermal conductivity. Pulse charging protocol does not help to mitigate the temperature difference on the bias of same total charging time, because of larger time-averaged heat generation rate than constant current charging. Suggestions on battery geometry optimizations for both prismatic/pouch battery and cylindrical battery are proposed to reduce the maximum temperature and mitigate the temperature gradient within the lithium ion battery

  3. Thermal enhancement of charge and discharge cycles for adsorbed natural gas storage

    KAUST Repository

    Rahman, Kazi Afzalur

    2011-07-01

    The usage of adsorbed natural gas (ANG) storage is hindered by the thermal management during the adsorption and desorption processes. An effective thermal enhancement is thus essential for the development of the ANG technology and the motivation for this study is the investigation of a gas storage system with internal thermal control. We employed a fin-tube type heat exchanger that is placed in a pressurized cylinder. A distributed-parameter model is used for the theoretical modeling and simulations are conducted at assorted charging and discharging conditions. These studies included the transient thermal behaviours of the elements within the ANG-charged cylinder and parameters such as pressure and temperature profiles of adsorbent have been obtained during charge and discharge cycles, and results are compared with a conventional compressed methane vessel. © 2011 Elsevier Ltd. All rights reserved.

  4. Evaluation of thermal stress in the anode chamber wall of a large volume magnetic bucket ion source

    International Nuclear Information System (INIS)

    Wells, Russell; Horiike, Hiroshi; Kuriyama, Masaaki; Ohara, Yoshihiro

    1984-02-01

    Thermal stress analysis was performed on the plasma chamber of the Large Volume Magnetic Multipole Bucket Ion Source (LVB) designed for use on the JT-60 NBI system. The energy absorbed by the walls of the plasma chambers of neutral beam injectors is of the order of 1% of the accelerator electrical drain power. A previous study indicates that a moderately high heat flux, of about 600W/cm 2 , is concentrated on the magnetic field cusp lines during normal full power operation. Abnormal arc discharges during conditioning of a stainless steel LVB produced localized melting of the stainless steel at several locations near the cusps lines. The power contained in abnormal arc discharges (arc spots) was estimated from the observed melting. Thermal stress analysis was performed numerically on representative sections of the copper LVB design for both stable and abnormal arc discharge conditions. Results show that this chamber should not fail due to thermal fatigue stesses arising from normal arc discharges. However, fatigue failure may occur after several hundred to a few thousand arc spots of 30mS duration at any one location. Limited arc discharge operation of the copper bucket was performed to partially verify the chamber's durability. (author)

  5. Supra-thermal charged particle energies in a low pressure radio-frequency electrical discharge in air

    International Nuclear Information System (INIS)

    Littlefield, R.G.

    1976-01-01

    Velocity spectra of supra-thermal electrons escaping from a low-pressure radio-frequency discharge in air have been measured by a time-of-flight method of original design. In addition, the energy spectra of the supra-thermal electrons and positive ions escaping from the rf discharge have been measured by a retarding potential method. Various parameters affecting the energy of the supra-thermal charged particles are experimentally investigated. A model accounting for the supra-thermal charged particle energies is developed and is shown to be consistent with experimental observations

  6. Benthos of a coastal power station thermal discharge canal

    Energy Technology Data Exchange (ETDEWEB)

    Bamber, R.N.; Spencer, J.F.

    1984-08-01

    Kingsnorth Power Station, on the river Medway Estuary, Kent, discharges cooling water into a canal comprising a 4 km creek system. A comprehensive investigation of the sublittoral benthic fauna of the discharge system was undertaken from January 1979 to September 1981. The macrofauna is significantly suppressed at sites along the discharge canal, representing a community with half the number of species comprising dense populations of a few dominant opportunistic species tolerant of thermal stress (e.g. Tubificoides, Cauleriella) and not those characteristic of organic pollution stress communities. The latter are regular summer immigrants in the creek, but persist only in low numbers if at all in the winter (e.g. Polydora ciliata). This suppression is the result of an approximately 10/sup 0/C temperature front between the heated discharge water and ambient estuarine water, passing over the sea bed with the ebbing and flooding tide four times each day. 39 references, 11 figures, 3 tables.

  7. Thermal pollution of rivers and reservoirs by discharges of heated water from thermal and nuclear power plants

    International Nuclear Information System (INIS)

    Makarov, I.

    1974-12-01

    The problems are discussed of the thermal pollution of rivers and water reservoirs by discharges of heated water from thermal and nuclear power plants. The problems concerned are quantitative and qualitative changes in biocenoses, the disturbance or extinction of flora and fauna, physiological changes in organisms and changes in the hydrochemical regime. (Z.M.)

  8. Discharging process of a finned heat pipe–assisted thermal energy storage system with high temperature phase change material

    International Nuclear Information System (INIS)

    Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

    2016-01-01

    Highlights: • The discharging process of a latent heat thermal energy storage system is studied. • The thermal energy storage system is assisted by finned heat pipes. • The influences of heat pipe spacing and fins geometrical features are studied. • Smaller heat pipe spacing enhances the solidification rate. • Better heat pipe and fin arrangements are determined. - Abstract: This paper presents the results of a numerical study conducted to investigate the discharging process of a latent heat thermal energy storage system assisted by finned heat pipes. A two-dimensional finite volume based numerical model along with enthalpy-porosity technique is employed to simulate the phase change of storage media during the discharging mode. The thermal energy storage system in this study consists of a square container, finned heat pipes, and potassium nitrate (KNO 3 ) as the phase change material. The charging process of the same thermal energy storage system was reported in an early paper by the authors. This paper reports the results of discharging process of the thermal energy storage system. The influences of heat pipe spacing, fin geometry and quantities as well as the effects of natural convection heat transfer on the thermal performance of the storage system were studied. The results indicate that the phase change material solidification process is hardly affected by the natural convection. Decreasing the heat pipe spacing results in faster discharging process and higher container base wall temperature. Increasing the fins length does not change the discharging time but yields higher base wall temperature. Using more fins also accelerates the discharging process and increases the container base wall temperature.

  9. Cesium-137 activities in fish residing in thermal discharges to Lake Michigan

    International Nuclear Information System (INIS)

    Spigarelli, S.A.

    1976-01-01

    The results of a study of 137 Cs activity in brown and rainbow trout and chinook salmon found in the thermal discharges from power plant sites on Lake Michigan, are reported. The objectives of the investigation were: (1) to compare 137 Cs activities in plume 'resident' fish with those in fish collected from reference (unheated) areas; (2) to compare the residence effect on the three sport fishes; and (3) to evaluate the radioecological significance of thermal discharge residence on temporal trends in 137 Cs accumulation by these fishes. Plume resident fish were identified and the residence time of these individuals estimated by the use of temperature-sensitive fish tags. Results are shown tabulated. (U.K.)

  10. Cesium-137 activities in fish residing in thermal discharges to Lake Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Spigarelli, S A [Argonne National Lab., Ill. (USA)

    1976-05-01

    The results of a study of /sup 137/Cs activity in brown and rainbow trout and chinook salmon found in the thermal discharges from power plant sites on Lake Michigan, are reported. The objectives of the investigation were: (1) to compare /sup 137/Cs activities in plume 'resident' fish with those in fish collected from reference (unheated) areas; (2) to compare the residence effect on the three sport fishes; and (3) to evaluate the radioecological significance of thermal discharge residence on temporal trends in /sup 137/Cs accumulation by these fishes. Plume resident fish were identified and the residence time of these individuals estimated by the use of temperature-sensitive fish tags. Results are shown tabulated.

  11. Enhancement of discharge performance of Li/CF x cell by thermal treatment of CF x cathode material

    Science.gov (United States)

    Zhang, Sheng S.; Foster, Donald; Read, Jeffrey

    In this work we demonstrate that the thermal treatment of CF x cathode material just below the decomposition temperature can enhance discharge performance of Li/CF x cells. The performance enhancement becomes more effective when heating a mixture of CF x and citric acid (CA) since CA serves as an extra carbon source. Discharge experiments show that the thermal treatment not only reduces initial voltage delay, but also raises discharge voltage. Whereas the measurement of powder impedance indicates the thermal treatment does not increase electronic conductivity of CF x material. Based on these facts, we propose that the thermal treatment results in a limited decomposition of CF x, which yields a subfluorinated carbon (CF x- δ), instead of a highly conductive carbon. In the case of CF x/AC mixture, the AC provides extra carbon that reacts with F 2 and fluorocarbon radicals generated by the thermal decomposition of CF x to form subfluorinated carbon. The process of thermal treatment is studied by thermogravimetric analysis and X-ray diffraction, and the effect of treatment conditions such as heating temperature, heating time and CF x/CA ratio on the discharge performance of CF x cathode is discussed. As an example, a Li/CF x cell using CF x treated with CA at 500 °C under nitrogen for 2 h achieved theretical specific capacity when being discharged at C/5. Impedance analysis indicates that the enhanced performance is attributed to a significant reduction in the cell reaction resistance.

  12. Modeling of the dilution of thermal discharges into the sea

    International Nuclear Information System (INIS)

    Boulot, F.; Hauguel, A.

    1981-01-01

    The report describes the differences in behaviour existing between tidal and tideless oceans with resulting consequences for mathematical modeling of thermal discharges and their dispersion off the coast where plant is located. Examples of studies performed at sites on the Channel and in the Mediterranean sea are also explained [fr

  13. Remote measurement of river discharge using thermal particle image velocimetry (PIV) and various sources of bathymetric information

    Science.gov (United States)

    Legleiter, Carl; Kinzel, Paul J.; Nelson, Jonathan M.

    2017-01-01

    Although river discharge is a fundamental hydrologic quantity, conventional methods of streamgaging are impractical, expensive, and potentially dangerous in remote locations. This study evaluated the potential for measuring discharge via various forms of remote sensing, primarily thermal imaging of flow velocities but also spectrally-based depth retrieval from passive optical image data. We acquired thermal image time series from bridges spanning five streams in Alaska and observed strong agreement between velocities measured in situ and those inferred by Particle Image Velocimetry (PIV), which quantified advection of thermal features by the flow. The resulting surface velocities were converted to depth-averaged velocities by applying site-specific, calibrated velocity indices. Field spectra from three clear-flowing streams provided strong relationships between depth and reflectance, suggesting that, under favorable conditions, spectrally-based bathymetric mapping could complement thermal PIV in a hybrid approach to remote sensing of river discharge; this strategy would not be applicable to larger, more turbid rivers, however. A more flexible and efficient alternative might involve inferring depth from thermal data based on relationships between depth and integral length scales of turbulent fluctuations in temperature, captured as variations in image brightness. We observed moderately strong correlations for a site-aggregated data set that reduced station-to-station variability but encompassed a broad range of depths. Discharges calculated using thermal PIV-derived velocities were within 15% of in situ measurements when combined with depths measured directly in the field or estimated from field spectra and within 40% when the depth information also was derived from thermal images. The results of this initial, proof-of-concept investigation suggest that remote sensing techniques could facilitate measurement of river discharge.

  14. Experimental study on thermal characteristics of positive leader discharges using Mach-Zehnder interferometry

    International Nuclear Information System (INIS)

    Zhou, X.; Zeng, R.; Zhuang, C.; Chen, S.

    2015-01-01

    Leader discharge is one of the main phases in long air gap breakdown, which is characterized by high temperature and high conductivity. It is of great importance to determine thermal characteristics of leader discharges. In this paper, a long-optical-path Mach-Zehnder interferometer was set up to measure the thermal parameters (thermal diameter, gas density, and gas temperature) of positive leader discharges in atmospheric air. IEC standard positive switching impulse voltages were applied to a near-one-meter point-plane air gap. Filamentary channels with high gas temperature and low density corresponding to leader discharges were observed as significant distortions in the interference fringe images. Typical diameters of the entire heated channel range from 1.5 mm to 3.5 mm with an average expansion velocity of 6.7 m/s. In contrast, typical diameters of the intensely heated region with a sharp gas density reduction range from 0.4 mm to 1.1 mm, about one third of the entire heated channel. The radial distribution of the gas density is calculated from the fringe displacements by performing an Abel inverse transform. The typical calculated gas density reduction in the center of a propagating leader channel is 80% to 90%, corresponding to a gas temperature of 1500 K to 3000 K based on the ideal gas law. Leaders tend to terminate if the central temperature is below 1500 K

  15. Experimental study on thermal characteristics of positive leader discharges using Mach-Zehnder interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, X., E-mail: zhouxuan12@mails.thu.edu.cn; Zeng, R.; Zhuang, C.; Chen, S. [Department of Electrical Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-15

    Leader discharge is one of the main phases in long air gap breakdown, which is characterized by high temperature and high conductivity. It is of great importance to determine thermal characteristics of leader discharges. In this paper, a long-optical-path Mach-Zehnder interferometer was set up to measure the thermal parameters (thermal diameter, gas density, and gas temperature) of positive leader discharges in atmospheric air. IEC standard positive switching impulse voltages were applied to a near-one-meter point-plane air gap. Filamentary channels with high gas temperature and low density corresponding to leader discharges were observed as significant distortions in the interference fringe images. Typical diameters of the entire heated channel range from 1.5 mm to 3.5 mm with an average expansion velocity of 6.7 m/s. In contrast, typical diameters of the intensely heated region with a sharp gas density reduction range from 0.4 mm to 1.1 mm, about one third of the entire heated channel. The radial distribution of the gas density is calculated from the fringe displacements by performing an Abel inverse transform. The typical calculated gas density reduction in the center of a propagating leader channel is 80% to 90%, corresponding to a gas temperature of 1500 K to 3000 K based on the ideal gas law. Leaders tend to terminate if the central temperature is below 1500 K.

  16. Experimental investigation on charging and discharging performance of absorption thermal energy storage system

    International Nuclear Information System (INIS)

    Zhang, Xiaoling; Li, Minzhi; Shi, Wenxing; Wang, Baolong; Li, Xianting

    2014-01-01

    Highlights: • A prototype of ATES using LiBr/H 2 O was designed and built. • Charging and discharging performances of ATES system were investigated. • ESE and ESD for cooling, domestic hot water and heating were obtained. - Abstract: Because of high thermal storage density and little heat loss, absorption thermal energy storage (ATES) is known as a potential thermal energy storage (TES) technology. To investigate the performance of the ATES system with LiBr–H 2 O, a prototype with 10 kW h cooling storage capacity was designed and built. The experiments demonstrated that charging and discharging processes are successful in producing 7 °C chilled water, 65 °C domestic hot water, or 43 °C heating water to meet the user’s requirements. Characteristics such as temperature, concentration and power variation of the ATES system during charging and discharging processes were investigated. The performance of the ATES system for supplying cooling, heating or domestic hot water was analyzed and compared. The results indicate that the energy storage efficiencies (ESE) for cooling, domestic hot water and heating are 0.51, 0.97, 1.03, respectively, and the energy storage densities (ESD) for cooling, domestic hot water and heating reach 42, 88, 110 kW h/m 3 , respectively. The performance is better than those of previous TES systems, which proves that the ATES system using LiBr–H 2 O may be a good option for thermal energy storage

  17. Large quantity production of carbon and boron nitride nanotubes by mechano-thermal process

    International Nuclear Information System (INIS)

    Chen, Y.; Fitzgerald, J.D.; Chadderton, L.; Williams, J.S.; Campbell, S.J.

    2002-01-01

    Full text: Nanotube materials including carbon and boron nitride have excellent properties compared with bulk materials. The seamless graphene cylinders with a high length to diameter ratio make them as superstrong fibers. A high amount of hydrogen can be stored into nanotubes as future clean fuel source. Theses applications require large quantity of nanotubes materials. However, nanotube production in large quantity, fully controlled quality and low costs remains challenges for most popular synthesis methods such as arc discharge, laser heating and catalytic chemical decomposition. Discovery of new synthesis methods is still crucial for future industrial application. The new low-temperature mechano-thermal process discovered by the current author provides an opportunity to develop a commercial method for bulk production. This mechano-thermal process consists of a mechanical ball milling and a thermal annealing processes. Using this method, both carbon and boron nitride nanotubes were produced. I will present the mechano-thermal method as the new bulk production technique in the conference. The lecture will summarise main results obtained. In the case of carbon nanotubes, different nanosized structures including multi-walled nanotubes, nanocells, and nanoparticles have been produced in a graphite sample using a mechano-thermal process, consisting of I mechanical milling at room temperature for up to 150 hours and subsequent thermal annealing at 1400 deg C. Metal particles have played an important catalytic effect on the formation of different tubular structures. While defect structure of the milled graphite appears to be responsible for the formation of small tubes. It is found that the mechanical treatment of graphite powder produces a disordered and microporous structure, which provides nucleation sites for nanotubes as well as free carbon atoms. Multiwalled carbon nanotubes appear to grow via growth of the (002) layers during thermal annealing. In the case of BN

  18. Simulation of electron thermal transport in H-mode discharges

    International Nuclear Information System (INIS)

    Rafiq, T.; Pankin, A. Y.; Bateman, G.; Kritz, A. H.; Halpern, F. D.

    2009-01-01

    Electron thermal transport in DIII-D H-mode tokamak plasmas [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] is investigated by comparing predictive simulation results for the evolution of electron temperature profiles with experimental data. The comparison includes the entire profile from the magnetic axis to the bottom of the pedestal. In the simulations, carried out using the automated system for transport analysis (ASTRA) integrated modeling code, different combinations of electron thermal transport models are considered. The combinations include models for electron temperature gradient (ETG) anomalous transport and trapped electron mode (TEM) anomalous transport, as well as a model for paleoclassical transport [J. D. Callen, Nucl. Fusion 45, 1120 (2005)]. It is found that the electromagnetic limit of the Horton ETG model [W. Horton et al., Phys. Fluids 31, 2971 (1988)] provides an important contribution near the magnetic axis, which is a region where the ETG mode in the GLF23 model [R. E. Waltz et al., Phys. Plasmas 4, 2482 (1997)] is below threshold. In simulations of DIII-D discharges, the observed shape of the H-mode edge pedestal is produced when transport associated with the TEM component of the GLF23 model is suppressed and transport given by the paleoclassical model is included. In a study involving 15 DIII-D H-mode discharges, it is found that with a particular combination of electron thermal transport models, the average rms deviation of the predicted electron temperature profile from the experimental profile is reduced to 9% and the offset to -4%.

  19. Large-aperture discharges in E-beam sustained CO2 amplifiers

    International Nuclear Information System (INIS)

    Leland, W.T.; Ganley, J.T.; Kircher, M.; York, G.W. Jr.

    1977-01-01

    The very large energy fluxes required for the attainment of scientific breakeven in laser-fusion experiments can only be obtained by the construction of multiple-beam, large-aperture lasers. Accordingly, the next generation CO 2 laser currently being designed at LASL consists of six electron-beam sustained amplifier modules, each module containing 12 large-aperture (approximately 30 x 30 cm) laser discharges sustained by (and surrounding) a single, cylindrical cold-cathode electron gun. The large scale and cylindrical geometry combine to generate substantial electric and magnetic field effects which can affect the uniformity of the electron-beam distribution, causing a number of difficulties including discharge and gain nonuniformities and potential arcing. In an effort to learn the magnitude of the associated difficulties and test various solutions for reducing the effects, a prototype module was constructed. This prototype was constructed full scale in the dimensions which will produce the discharge nonuniformities and measurements were made of the electron beam uniformity, discharge uniformity, and gain uniformity under a wide range of experimental conditions. These results indicate that under worse case conditions and nonuniformities, while severe, are within acceptable limits and can be reduced even further by minor design changes. Perhaps more importantly, calculational models have been developed which agree adequately enough with the data so that they can be used with reasonable confidence as a data base for predicting the performance of the final design of the amplifier modules and the effects of any changes which may be required

  20. Experimental study for thermal striping phenomena of parallel triple-jet. Effects of the difference between hot jets and cold jet in discharged temperature and velocity on convective mixing

    International Nuclear Information System (INIS)

    Kimura, Nobuyuki; Tokuhiro, A.; Miyakoshi, Hiroyuki

    1996-10-01

    Elucidation on thermal hydraulic behavior of Thermal Striping is of importance for a reactor safety, which is arisen form exit temperature difference of fuel subassemblies. Since its temperature fluctuation may cause thermal cycle fatigue on upper internal structure (UIS). A series of experiments was performed using the Thermal Striping water test facility in order to investigate the mixing phenomena on three vertical jets with exit velocity and temperature differences. The parameters were the velocity and temperature of the jets at discharge nozzles. The local velocities were measured by Ultrasound Velocity Profile (UVP) monitor and Laser Doppler Anemometry (LDA), and temperature distributions were measured by thermocouples. This report mainly examined the experimental results of temperature measurements. There is a typical region where the gradient of the temperature variation in the triple-jet: that is the Convective Mixing region. This region is independent of the discharged temperature difference, and spreads with larger velocity difference among the jets. For isovelocity discharge conditions, non-dimensional temperature fields are almost independent of discharged temperature differences within Convective Mixing region. Consequently, the effect of temperature difference is negligible compared to that of velocity difference on the flow field. There are remarkable frequencies of 2-5Hz in temperature fluctuation due to a oscillation of the central jet (cold jet) for this condition. While, for non-isovelocity discharge condition, there are no remarkable frequencies. Hence, it is clear that there is the region where a large thermal fatigue is imposed by Thermal Striping against structures of Fast Reactor. It is suggested that the structures have to be placed outside of Convective Mixing region. Also, it is considered that typical frequencies in temperature fluctuation are controlled by giving a discharge velocity difference between cold and hot jets. (J.P.N.)

  1. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge

    International Nuclear Information System (INIS)

    Valdivia B, R.; Pacheco S, J.; Pacheco P, M.; Ramos F, F.; Cruz A, A.; Velazquez P, S.

    2008-01-01

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  2. Impact of thermal power plant discharges on the coastal environment of Tuticorin

    International Nuclear Information System (INIS)

    Palanichamy, S.; Ragumaran, S.; Rajendran, A.

    2002-01-01

    In the present study an attempt is made to delineate the changes in the environmental quality caused due to effluent discharges from Tuticorin thermal power station. Water samples were collected from 19 stations covering three different zones. Plankton and benthic fauna were collected from 5 stations. The data indicated that environmental parameters like DO, pH and nutrients were slightly altered at zone II, while, water temperature was rather higher by about 8 degC above the ambient temperature. Further suspended solids, turbidity values were also found to be higher. The stations located near the hot effluent discharge (zone II) recorded poor plankton diversity and density. Benthic fauna was also found to be affected in the vicinity of the hot effluent discharges. The changes encountered during the study period are discussed in this paper. (author)

  3. Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

    Science.gov (United States)

    Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan; Ehn, Andreas; Aldén, Marcus; Larsson, Anders; Kusano, Yukihiro

    2014-12-01

    Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating current (AC) power source. The plasma column extended beyond the water-cooled stainless steel electrodes and was stabilized by matching the flow speed of the turbulent air jet with the rated output power. Comprehensive investigations were performed using high-speed movies measured over the plasma column, synchronized with simultaneously recorded current and voltage waveforms. Dynamic details of the novel non-equilibrium discharge are revealed, which is characterized by a sinusoidal current waveform with amplitude stabilized at around 200 mA intermediate between thermal arc and glow discharge, shedding light to the governing mechanism of the sustained spark-suppressed AC gliding arc discharge.

  4. 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.

  5. Study of thermal and hydraulic phenomena going along with the discharge of hot waters from a power generation plant

    International Nuclear Information System (INIS)

    Syrmalenios, Panayotis

    1973-01-01

    This short research thesis aims at taking stock of problems raised by the discharge of high temperature water from a power plant into rivers, lakes and seas from a thermal and hydraulic point of view. The author proposes an overview of ecological, legal, and recirculation problems. He describes the various phenomena going along these discharges at the vicinity of the discharge and far from it. He also proposes an overview of methods used to study these thermal and hydraulic effects: 'in-situ' studies, experimental methods, theoretical methods. Appendices address floating jets and layered flows [fr

  6. Large area, surface discharge pumped, vacuum ultraviolet light source

    Science.gov (United States)

    Sze, R.C.; Quigley, G.P.

    1996-12-17

    Large area, surface discharge pumped, vacuum ultraviolet (VUV) light source is disclosed. A contamination-free VUV light source having a 225 cm{sup 2} emission area in the 240-340 nm region of the electromagnetic spectrum with an average output power in this band of about 2 J/cm{sup 2} at a wall-plug efficiency of approximately 5% is described. Only ceramics and metal parts are employed in this surface discharge source. Because of the contamination-free, high photon energy and flux, and short pulse characteristics of the source, it is suitable for semiconductor and flat panel display material processing. 3 figs.

  7. A Preliminary Investigation of the Effect of Ocean Thermal Energy Conversion (OTEC Effluent Discharge Options on Global OTEC Resources

    Directory of Open Access Journals (Sweden)

    Gérard Nihous

    2018-03-01

    Full Text Available A simple algorithm previously used to evaluate steady-state global Ocean Thermal Energy Conversion (OTEC resources is extended to probe the effect of various effluent discharge methodologies. It is found that separate evaporator and condenser discharges potentially increase OTEC net power limits by about 60% over a comparable mixed discharge scenario. This stems from a relatively less severe degradation of the thermal resource at given OTEC seawater flow rates, which corresponds to a smaller heat input into the ocean. Next, the most practical case of a mixed discharge into the mixed layer is found to correspond to only 80% of the so-called baseline case (mixed discharge at a water depth of initial neutral buoyancy. In general, locating effluent discharges at initial neutral-buoyancy depths appears to be nearly optimal in terms of OTEC net power production limits. The depth selected for the OTEC condenser effluent discharge, however, has by far the greatest impact. Clearly, these results are preliminary and should be investigated in more complex ocean general circulation models.

  8. Thermal motion of carbon clusters and production of carbon nanotubes by gravity-free arc discharge

    International Nuclear Information System (INIS)

    Mieno, T.; Takeguchi, M.

    2006-01-01

    Thermal and diffusion properties of hot gas around a dc arc discharge under a gravity-free condition are investigated using a jet plane in order to improve the arc production of carbon clusters. Spherically symmetric temperature distribution of He gas around the arc plasma and monotonic slow expansion of the high-temperature region are observed. By means of the passive-type Mie scattering method, random slow diffusion of carbon clusters around the arc plasma is clearly observed under the gravity-free condition. This indicates that carbon clusters including single-walled carbon nanotubes are synthesized around the arc plasma where the He temperature is higher than 1000 K. It is confirmed that large bundles of fatter single-walled carbon nanotubes are produced under the gravity-free condition

  9. Potential of electrical gas discharges for pollution control of large gas volumes

    International Nuclear Information System (INIS)

    Kogelschatz, U.

    1997-01-01

    Non-equilibrium gas discharges in many cases offer an innovative approach to the solution cf industrial air pollution problems. Negative corona discharges are used in electrostatic precipitators to collect dust and fly ash particles. Pulsed positive streamer coronas, dielectric-barrier discharges and possibly also flow-stabilised high pressure glow discharges are emerging technologies for the destruction of air pollutants like nitrogen oxides and sulfur dioxide in flue gases and volatile organic compounds (VOCs) in industrial effluents. The different discharge types are discussed with special emphasis on their potential for upscaling. Major applications are expected particularly in the removal of dilute concentrations of air pollutants, in odour control and in the simultaneous removal of different pollutants. Dielectric-barrier discharges exhibit disposal efficiencies similar to those of pulsed positive streamer coronas and require less sophisticated feeding circuits in large-scale industrial applications. (author)

  10. Suitability of thermal plasmas for large-area bacteria inactivation on temperature-sensitive surfaces – first results with Geobacillus stearothermophilus spores

    International Nuclear Information System (INIS)

    Szulc, M; Schein, S; Schaup, J; Zimmermann, S; Schein, J

    2017-01-01

    The application of thermal plasma for large-area bacteria inactivation on temperature-sensitive surfaces is not a common one. Nonetheless, there are thermal plasma generators which offer a high sheath homogeneity and have proven to be suitable for treatment of thermally sensitive materials in the past. To investigate the suitability of such plasmas, agar dishes plated with endospores of Geobacillus stearothermophilus have been treated with a long arc plasma generator called LARGE. The achieved results have been compared with a commercially available non-thermal plasma generator. A significant inactivation of the endospores could be observed only after 60 s of treatment with the thermal plasma source. This was not possible with the non-thermal generator. Moreover, no temperature damage or increase of the specimen could be detected. An attempt to determine the main agents responsible for the microbicidal effects have been made – the influence of plasma gas composition, discharge current and treatment time has been investigated. Significant improvements in the disinfection rates after adding small amounts of nitrogen to the plasma gas could be observed. A first discussion regarding the suitability of thermal plasmas for bacteria inactivation has been given. (paper)

  11. Hydraulic modeling of thermal discharges into shallow, tidal affected streams

    International Nuclear Information System (INIS)

    Copp, H.W.; Shashidhara, N.S.

    1981-01-01

    A two-unit nuclear fired power plant is being constructed in western Washington state. Blowdown water from cooling towers will be discharged into the Chehalis River nearby. The location of a diffuser is some 21 miles upriver from Grays Harbor on the Pacific Ocean. Because the Chehalis River is classified as an excellent stream from the standpoint of water quality, State regulatory agencies required demonstration that thermal discharges would maintain water quality standards within fairly strict limits. A hydraulic model investigation used a 1:12 scale, undistorted model of a 1300-foot river reach in the vicinity of the diffuser. The model scale was selected to insure fully turbulent flows both in the stream and from the diffuser (Reynolds similitude). Model operation followed the densimetric Froude similitude. Thermistors were employed to measure temperatures in the model; measurements were taken by computer command and such measurements at some 250 positions were effected in about 2.5 seconds

  12. Thermal Conductivity Changes Due to Degradation of Cathode Film Subjected to Charge-Discharge Cycles in a Li Ion Battery

    Science.gov (United States)

    Jagannadham, K.

    2018-05-01

    A battery device with graphene platelets as anode, lithium nickel manganese oxide as cathode, and solid-state electrolyte consisting of layers of lithium phosphorous oxynitride and lithium lanthanum titanate is assembled on the stainless steel substrate. The battery in a polymer enclosure is subjected to several electrical tests consisting of charge and discharge cycles at different current and voltage levels. Thermal conductivity of the cathode layer is determined at the end of charge-discharge cycles using transient thermoreflectance. The microstructure and composition of the cathode layer and the interface between the cathode, the anode, and the electrolyte are characterized using scanning electron microscopy and elemental mapping. The decrease in the thermal conductivity of the same cathode observed after each set of electrical test cycles is correlated with the volume changes and formation of low ionic and thermal conductivity lithium oxide and lithium oxychloride at the interface and along porous regions. The interface between the metal current collector and the cathode is also found to be responsible for the increase in thermal resistance. The results indicate that changes in the thermal conductivity of the electrodes provide a measure of the resistance to heat transfer and degradation of ionic transport in the cathode accompanying the charge-discharge cycles in the batteries.

  13. Numerical investigation of temperature distribution and thermal performance while charging-discharging thermal energy in aquifer

    International Nuclear Information System (INIS)

    Ganguly, Sayantan; Mohan Kumar, M.S.; Date, Abhijit; Akbarzadeh, Aliakbar

    2017-01-01

    Highlights: • A 3D coupled thermo-hydrogeological numerical model of an ATES system is presented. • Importance of a few parameters involved in the study is determined. • Thermal energy discharge by the ATES system for two seasons is estimated. • A strategy and a safe well spacing are proposed to avoid thermal interference. • The proposed model is applied to simulate a real life ATES field study. - Abstract: A three-dimensional (3D) coupled thermo-hydrogeological numerical model for a confined aquifer thermal energy storage (ATES) system underlain and overlain by rock media has been presented in this paper. The ATES system operates in cyclic mode. The model takes into account heat transport processes of advection, conduction and heat loss to confining rock media. The model also includes regional groundwater flow in the aquifer in the longitudinal and lateral directions, geothermal gradient and anisotropy in the aquifer. Results show that thermal injection into the aquifer results in the generation of a thermal-front which grows in size with time. The thermal interference caused by the premature thermal-breakthrough when the thermal-front reaches the production well results in the fall of system performance and hence should be avoided. This study models the transient temperature distribution in the aquifer for different flow and geological conditions which may be effectively used in designing an efficient ATES project by ensuring safety from thermal-breakthrough while catering to the energy demand. Parameter studies are also performed which reveals that permeability of the confining rocks; well spacing and injection temperature are important parameters which influence transient heat transport in the subsurface porous media. Based on the simulations here a safe well spacing is proposed. The thermal energy produced by the system in two seasons is estimated for four different cases and strategy to avoid the premature thermal-breakthrough in critical cases is

  14. Active species in a large volume N2-O2 post-discharge reactor

    International Nuclear Information System (INIS)

    Kutasi, K; Pintassilgo, C D; Loureiro, J; Coelho, P J

    2007-01-01

    A large volume post-discharge reactor placed downstream from a flowing N 2 -O 2 microwave discharge is modelled using a three-dimensional hydrodynamic model. The density distributions of the most populated active species present in the reactor-O( 3 P), O 2 (a 1 Δ g ), O 2 (b 1 Σ g + ), NO(X 2 Π), NO(A 2 Σ + ), NO(B 2 Π), NO 2 (X), O 3 , O 2 (X 3 Σ g - ) and N( 4 S)-are calculated and the main source and loss processes for each species are identified for two discharge conditions: (i) p = 2 Torr, f = 2450 MHz, and (ii) p = 8 Torr, f = 915 MHz; in the case of a N 2 -2%O 2 mixture composition and gas flow rate of 2 x 10 3 sccm. The modification of the species relative densities by changing the oxygen percentage in the initial gas mixture composition, in the 0.2%-5% range, are presented. The possible tuning of the species concentrations in the reactor by changing the size of the connecting afterglow tube between the active discharge and the large post-discharge reactor is investigated as well

  15. Overview of the issues surrounding thermal discharges in the Des Plaines River

    Energy Technology Data Exchange (ETDEWEB)

    1979-04-01

    This review effort was undertaken to clarify and, if possible, quantify the issues surrounding the thermal input into the lower Des Plaines River from the Commonwealth Edison Joliet Electrical Generation Facility. The central issue is whether or not a reduction of the thermal discharge from the facility would produce beneficial environmental effects. This issue is clouded due to the fact of a number of environmental problems. These problems include: the river water quality, sediment quality, and barge traffic impacts. These variables, coupled with the uncertain future stream volume and conflicting data, prevent any simplistic conclusions from being drawn. Thus, any short-term study can only result in an overview of the situation.

  16. Diffusion of condenser water discharge

    International Nuclear Information System (INIS)

    Iwakiri, Toshio

    1977-01-01

    Thermal and nuclear power stations in Japan are mostly located in coastal area, and the cooling water is discharged into sea as warm water. Recently, large interest is taken in this matter, and it is desirable to predict the diffusion of warm discharge accurately and to take effective measures for lowering the temperature. As for the methods of predicting the diffusion of warm discharge, simplified estimation, mathematical analysis and hydrographical model experiment are used corresponding to objects and conditions. As for the measures to lower temperature, the method of discharging warm water into deep sea bottom was confirmed to be very effective. In this paper, the phenomena of diffusion of warm discharge in sea, the methods of predicting the diffusion of warm discharge, and the deep sea discharge as the measure for lowering temperature are outlined. The factors concerning the diffusion of warm discharge in sea are the conditions of discharge, topography and sea state, and the diffusion is roughly divided into mixing diffusion in the vicinity of warm water outlet and eddy diffusion in distant region. It is difficult to change artificially the conditions of diffusion in distant region, and the measures of raising the rate of dilution in near region are effective, therefore the deep sea discharge is adopted. (Kako, I.)

  17. Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan

    2014-01-01

    Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating...... current (AC) power source. The plasma column extended beyond the water-cooled stainless steel electrodes and was stabilized by matching the flow speed of the turbulent air jet with the rated output power. Comprehensive investigations were performed using high-speed movies measured over the plasma column...

  18. Carbon coated CoS_2 thermal battery electrode material with enhanced discharge performances and air stability

    International Nuclear Information System (INIS)

    Xie, Song; Deng, Yafeng; Mei, Jun; Yang, Zhaotang; Lau, Woon-Ming; Liu, Hao

    2017-01-01

    Graphical abstract: A novel carbon coated CoS_2 composite is prepared and investigated as a cathode material for thermal batteries. - Highlights: • A novel C@CoS_2 composite is successfully prepared by hydrothermal method. • The growth of CoS_2 in the glucose solution results in a smaller grain size. • The coating of carbon favors electron transfer and buffers polysulfides formation. • The in situ coated carbon layer effectively prevents the oxidation of CoS_2. • The C@CoS_2 composite shows competitive thermal stability and discharge property. - Abstract: Cobalt disulfide (CoS_2) is a promising thermal battery electrode material for its superior thermal stability and discharge performance. However, the low natural resource and poor air stability restrict its application in thermal battery fabrication. In this work, carbon coated CoS_2 composite was prepared by a facile one-pot hydrothermal method with glucose as carbon source. During the growth of CoS_2, the glucose molecules were in situ adsorbed and carbonized on the surface of the as-synthesized CoS_2, and the resultant carbon coating provided improved electrical conductivity and discharge performances to the composite. The thermal battery cell, which was fabricated with such a composite cathode and with a Li-Si anode, can output a capacity of 235.8 mAh g"−"1 and an energy density of 416.9 Wh kg"−"1 at a cut-off voltage of 1.7 V. This carbon coated CoS_2 composite also presented enhanced air stability. After being stored in dry air for 3 months, the composite can still provide a capacity of 232.4 mAh g"−"1 to 1.7 V, whereas the capacity of bare CoS_2 stored with the same condition dropped from 202.4 mAh g"−"1 to 189.7 mAh g"−"1.

  19. Influence of accelerated thermal charging and discharging cycles on thermo-physical properties of organic phase change materials for solar thermal energy storage applications

    International Nuclear Information System (INIS)

    Raam Dheep, G.; Sreekumar, A.

    2015-01-01

    Highlights: • Identification of organic phase change materials namely benzamide and sebacic acid. • Thermal reliability studies on identified phase change materials. • Measurement of phase transition temperature and latent heat of fusion. • Analysis of relative percentage difference (RPD%) in heat of fusion and melting temperature of benzamide and sebacic acid. - Abstract: Integration of appropriate thermal energy storage system plays a predominant role in upgrading the efficiency of solar thermal energy devices by reducing the incongruity between energy supply and demand. Latent heat thermal energy storage based on phase change materials (PCM) is found to be the most efficient and prospective method for storage of solar thermal energy. Ensuring the thermal reliability of PCM through large number of charging (melting) and discharging (solidification) cycles is a primary prerequisite to determine the suitability of PCM for a specific thermal energy storage applications. The present study explains the experimental analysis carried out on two PCM’s namely benzamide and sebacic acid to check the compatibility of the material in solar thermal energy storage applications. The selected materials were subjected to one thousand accelerated melting and solidification cycles in order to investigate the percentage of variation at different stages on latent heat of fusion, phase transition temperature, onset and peak melting temperature. Differential Scanning Calorimeter (DSC) was used to determine the phase transition temperature and heat of fusion upon completion of every 100 thermal cycles and continued up to 1000 cycles. Relative Percentage Difference (RPD%) is calculated to find out the absolute deviation of melting temperature and latent heat of fusion with respect to zeroth cycle. The experimental study recorded a melting temperatures of benzamide and sebacic acid as 125.09 °C and 135.92 °C with latent heat of fusion of 285.1 (J/g) and 374.4 (J/g). The

  20. Development of a spatially uniform fast ionization wave in a large-volume discharge

    International Nuclear Information System (INIS)

    Zatsepin, D.V.; Starikovskaya, S.M.; Starikovskii, A.Yu.

    1998-01-01

    A study is made of a high-voltage nanosecond breakdown in the form of a fast ionization wave produced in a large-volume (401) discharge chamber. The propagation speed of the wave front and the integral energy deposition in a plasma are measured for various regimes of the air discharge at pressures of 10 -2 -4 Torr. A high degree of both the spatial uniformity of the discharge and the reproducibility of the discharge parameters is obtained. The possibility of the development of a fast ionization wave in an electrodeless system is demonstrated. A transition of the breakdown occurring in the form of a fast ionization wave into the streamer breakdown is observed. It is shown that such discharges are promising for technological applications

  1. Environmental effects of thermal and radioactive discharges from nuclear power plants in the boreal brackish-water conditions of the northern Baltic Sea

    OpenAIRE

    Ilus, Erkki

    2009-01-01

    During recent decades, thermal and radioactive discharges from nuclear power plants into the aquatic environment have become the subject of lively debate as an ecological concern. The target of this thesis was to summarize the large quantity of results obtained in extensive monitoring programmes and studies carried out in recipient sea areas off the Finnish nuclear power plants at Loviisa and Olkiluoto during more than four decades. The Loviisa NPP is located on the coast of the Gulf of Finla...

  2. Charging-discharging characteristics of macro-encapsulated phase change materials in an active thermal energy storage system for a solar drying kiln

    Directory of Open Access Journals (Sweden)

    Kumar Shailendra

    2017-01-01

    Full Text Available The present study explores suitability of two phase change materials (PCM for development of an active thermal storage system for a solar drying kiln by studying their melting and solidification behaviors. A double glass glazing prototype solar kiln was used in the study. The storage system consisted of a water storage tank with PCM placed inside the water in high density polyethylene containers. The water in the tank was heated with help of solar energy using an evacuated tube collector array. The melting and solidification temperature curves of PCM were obtained by charging and discharging the water tank. The study illustrated the utility of the PCM in using the stored thermal energy during their discharge to enhance the temperature inside the kiln. The rate of temperature reduction was found to be higher for paraffin wax as compared to a fatty acid based PCM. The water temperature during the discharge of the PCM showed dependence on the discharge characteristics of each PCM suggesting their suitability in designing active thermal storage systems.

  3. Contribution to the thermal study of a dielectric barrier discharge reactor

    International Nuclear Information System (INIS)

    Dubus, Nicolas

    2009-01-01

    This thesis aims to study the thermal behaviour of a laboratory Dielectric Barrier Discharge (DBD) reactor. An experimental study was first realized to measure temperatures at different points of the reactor by using optic fibers. These measurements were performed in transient and steady states. To examine the influence of heat losses, not insulated and insulated reactors were considered. The influence of the nature and the form of the applied voltage was else considered. Experiments were conducted with a sinusoidal voltage and a pulsed power supply. (author) [fr

  4. Biological impact assessment of thermal discharges in the vicinity of Madras Atomic Power Station, Kalpakkam, India

    International Nuclear Information System (INIS)

    Shahul Hameed, P.; Syed Mohamed, H.E.; Krishnamoorthy, R.

    2007-01-01

    Madras Atomic Power Station (MAPS), Kalpakkam uses seawater as tertiary coolant at the rate of 35m 3 /sec employing a once through type of circuit. The discharged water travels as a canal and mixes with seawater at the mixing zone. The present study investigated the impact of the discharged thermal effluent on the physical chemical and biological quality of the receiving seawater body. The thermal plume is shore attached and extended up to 300 m from the shore and registered a ΔT of 3-4 degC. The shore attached thermal plume adversely affected the density and distribution of macro benthic animals. The benthos are absent in the mixing zone and their density decreased about 500 m on either side of the mixing zone. The natural shift in the mixing zone provides opportunities for the recolonization of macro benthos. The thermal tolerance study revealed that the experimental fish species Mugil cephalus and Alepeus djidapa did not show any mortality or loss of equilibrium at ΔT 5 degC (33 degC) and ΔT 7 degC (35 degC) and the maximum ΔT recorded at the impact area is 6 degC. The gradual increase in temperature as found in the plume favors the fishes to escape the acute thermal exposures. (author)

  5. Origin of fin-clipped salmonids collected at two thermal discharges on Lake Michigan

    International Nuclear Information System (INIS)

    Romberg, G.P.; Thommes, M.M.; Spigarelli, S.A.

    1974-01-01

    Fin clips observed on fish collected during tagging studies at the Point Beach and Waukegan thermal discharges were recorded and the data were tabulated by species. Using fin clip and fish size, attempts were made to identify probable stocking locations and dates from agency records. Data are presented for lake trout, rainbow trout, brown trout, and Coho salmon. Tables are presented to show probable stocking locations and dates

  6. Large-scale hydrological model river storage and discharge correction using a satellite altimetry-based discharge product

    Science.gov (United States)

    Emery, Charlotte Marie; Paris, Adrien; Biancamaria, Sylvain; Boone, Aaron; Calmant, Stéphane; Garambois, Pierre-André; Santos da Silva, Joecila

    2018-04-01

    Land surface models (LSMs) are widely used to study the continental part of the water cycle. However, even though their accuracy is increasing, inherent model uncertainties can not be avoided. In the meantime, remotely sensed observations of the continental water cycle variables such as soil moisture, lakes and river elevations are more frequent and accurate. Therefore, those two different types of information can be combined, using data assimilation techniques to reduce a model's uncertainties in its state variables or/and in its input parameters. The objective of this study is to present a data assimilation platform that assimilates into the large-scale ISBA-CTRIP LSM a punctual river discharge product, derived from ENVISAT nadir altimeter water elevation measurements and rating curves, over the whole Amazon basin. To deal with the scale difference between the model and the observation, the study also presents an initial development for a localization treatment that allows one to limit the impact of observations to areas close to the observation and in the same hydrological network. This assimilation platform is based on the ensemble Kalman filter and can correct either the CTRIP river water storage or the discharge. Root mean square error (RMSE) compared to gauge discharges is globally reduced until 21 % and at Óbidos, near the outlet, RMSE is reduced by up to 52 % compared to ENVISAT-based discharge. Finally, it is shown that localization improves results along the main tributaries.

  7. Impact of Tab Location on Large Format Lithium-Ion Pouch Cell Based on Fully Coupled Tree-Dimensional Electrochemical-Thermal Modeling

    International Nuclear Information System (INIS)

    Samba, Ahmadou; Omar, Noshin; Gualous, Hamid; Capron, Odile; Van den Bossche, Peter; Van Mierlo, Joeri

    2014-01-01

    This paper presents extensive three-dimensional (3D) simulations of large LiFPO 4 pouch cells. 3D simulations of the Li-ion battery behavior are highly nonlinear and computationally demanding. Coupling electrochemical modeling to thermal models represents an important step towards accurate simulation of the Li-ion battery. Non-uniform temperature, potential and current density through the battery induce non-uniform use of the active material and can have a negative impact on cell performance and lifetime. Different pouch cell designs, with different tab locations, have been investigated in term of performance, current density, potential and heat distributions. The model is first validated with experimental data at different current discharge rates. Afterwards, the electrochemical, thermal and electrical behaviors over each cell design under high discharge rate (4 I t ) are compared between configurations. It has been shown that the designs with symmetrical configurations show uniform potential and current density gradient, which minimize the ohmic heat and lead to more uniform active material utilization and temperature distributions across the cell surface.Introduction

  8. A multilayer electro-thermal model of pouch battery during normal discharge and internal short circuit process

    International Nuclear Information System (INIS)

    Chen, Mingbiao; Bai, Fanfei; Song, Wenji; Lv, Jie; Lin, Shili

    2017-01-01

    Highlights: • 2D network equivalent circuit considers the interplay of cell units. • The temperature non-uniformity Φ of multilayer model is bigger than that of lumped model. • The temperature non-uniformity is quantified and the reason of non-uniformity is analyzed. • Increasing the thermal conductivity of the separator can effectively relieve the heat spot effect of ISC. - Abstract: As the electrical and thermal characteristic will affect the batteries’ safety, performance, calendar life and capacity fading, an electro-thermal coupled model for pouch battery LiFePO_4/C is developed in normal discharge and internal short circuit process. The battery is discretized into many cell elements which are united as a 2D network equivalent circuit. The electro-thermal model is solved with finite difference method. Non-uniformity of current distribution and temperature distribution is simulated and the result is validated with experiment data at various discharge rates. Comparison of the lumped model and the multilayer structure model shows that the temperature non-uniformity Φ of multilayer model is bigger than that of lumped model and shows more precise. The temperature non-uniformity is quantified and the reason of non-uniformity is analyzed. The electro-thermal model can also be used to guide the safety design of battery. The temperature of the ISC element near tabs is the highest because the equivalent resistance of the external circuit (not including the ISC element) is the smallest when the resistance of cell units is small. It is found that increasing the thermal conductivity of integrated layer can effectively relieve the heat spot effect of ISC.

  9. Saturated Resin Ectopic Regeneration by Non-Thermal Dielectric Barrier Discharge Plasma

    Directory of Open Access Journals (Sweden)

    Chunjing Hao

    2017-11-01

    Full Text Available Textile dyes are some of the most refractory organic compounds in the environment due to their complex and various structure. An integrated resin adsorption/Dielectric Barrier Discharge (DBD plasma regeneration was proposed to treat the indigo carmine solution. It is the first time to report ectopic regeneration of the saturated resins by non-thermal Dielectric Barrier Discharge. The adsorption/desorption efficiency, surface functional groups, structural properties, regeneration efficiency, and the intermediate products between gas and liquid phase before and after treatment were investigated. The results showed that DBD plasma could maintain the efficient adsorption performance of resins while degrading the indigo carmine adsorbed by resins. The degradation rate of indigo carmine reached 88% and the regeneration efficiency (RE can be maintained above 85% after multi-successive regeneration cycles. The indigo carmine contaminants were decomposed by a variety of reactive radicals leading to fracture of exocyclic C=C bond, which could cause decoloration of dye solution. Based on above results, a possible degradation pathway for the indigo carmine by resin adsorption/DBD plasma treatment was proposed.

  10. Estimation of Channel-Forming Discharge and Large-Event Geomorphic Response Using HEC-RAS

    Science.gov (United States)

    Hamilton, P.; Strom, K.; Hosseiny, S. M. H.

    2015-12-01

    The goal of the present work was to consider the functionality and applicability of HEC-RAS sediment transport simulations in two situations. The first was as a mode for obtaining quick estimates of the effective discharge, one measure of channel-forming discharge, and the second was as a mode to quickly estimate sediment transport and the commensurate potential erosion and deposition during large flood events. Though there are many other sediment transport and morphodynamic models available, e.g., CCHE1D, Nays2DH, we were interested in using HEC-RAS since this is the model of choice for many regulatory bodies, e.g., FEMA, cities, and counties. This makes using the sediment transport capability of HEC-RAS a natural extension of models that already otherwise exist and are well calibrated. In first looking at the utility of these models, we wanted to estimate the effective discharge of streams. Effective discharge is one way of defining the channel-forming discharge for a stream and is therefore an important parameter in natural channel design and restoration efforts. By running this range of floods, one can easily obtain an estimate for recurrence interval most responsible for moving the majority of sediment over a long time period. Results were compared to data collected within our research group on the Brazos River (TX). Effective discharge is an important estimate, particularly in understanding the equilibrium channel condition. Nevertheless, large floods are contemporaneously catastrophic and understanding their potential effects is desirable. Finally, we performed some sensitivity analysis to better understand the underlying assumptions of the various sediment transport model options and how they might affect the outcome of the aforementioned computations.

  11. Daytime space cooling with phase change material ceiling panels discharged using rooftop photovoltaic/thermal panels and night-time ventilation

    DEFF Research Database (Denmark)

    Bourdakis, Eleftherios; Pean, Thibault Quentin; Gennari, Luca

    2016-01-01

    The possibility of using photovoltaic/thermal panels for producing cold water through the process of night-time radiative cooling was experimentally examined. The cold water was used to discharge phase change material in ceiling panels in a climatic chamber. Both night-time radiative cooling...... the photovoltaic/thermal varied from 56% to 122%. The phase change material ceiling panels were thus, capable of providing an acceptable thermal environment and the photovoltaic/thermal panels were able to provide most of the required electricity and cold water needed for cooling....

  12. Discharge current characteristics as an 'electrical method' for glow discharge plasma diagnosis

    International Nuclear Information System (INIS)

    Toma, M.; Paraschivescu, Alina; Morminches, Anisoara

    2001-01-01

    In its simplest form, the glow discharge can be established by passing an electric current through gas between two electrodes. The gas and the electrodes are contained in an insulating envelope. In many technological applications, and not only, the plasma devices are often treated like a black box. There is a series of external parameters or control variables which can be adjusted to obtain a desired effect, namely, the operating voltage, gas pressure, gas nature, gas flow rate, magnetic field strength and magnetic field configuration, electric field geometry, interelectrode distance, and cathode characteristics. The discharge current can be controlled by each of the above control variables. The core idea of this work is the following: a lot of information about the phenomena from the discharge volume, at electrodes or at the discharge bounding wall surface, can be obtained knowing how the change of one of the control parameters influences the discharge current. The following regimes were analyzed: dark discharges (background ionization, saturation regime, Townsend regime, corona regime), glow discharge (the normal and abnormal discharge) and arc discharge (glow to arc transition, non-thermal arcs, thermal arcs). It was concluded that the nonlinearity in the shape of the discharge current characteristics as a function of an external control parameter, can be correlated with the elementary processes and the dynamics of different space charge structures generated in plasma devices. (authors)

  13. Evaluation of the depth-integration method of measuring water discharge in large rivers

    Science.gov (United States)

    Moody, J.A.; Troutman, B.M.

    1992-01-01

    The depth-integration method oor measuring water discharge makes a continuos measurement of the water velocity from the water surface to the bottom at 20 to 40 locations or verticals across a river. It is especially practical for large rivers where river traffic makes it impractical to use boats attached to taglines strung across the river or to use current meters suspended from bridges. This method has the additional advantage over the standard two- and eight-tenths method in that a discharge-weighted suspended-sediment sample can be collected at the same time. When this method is used in large rivers such as the Missouri, Mississippi and Ohio, a microwave navigation system is used to determine the ship's position at each vertical sampling location across the river, and to make accurate velocity corrections to compensate for shift drift. An essential feature is a hydraulic winch that can lower and raise the current meter at a constant transit velocity so that the velocities at all depths are measured for equal lengths of time. Field calibration measurements show that: (1) the mean velocity measured on the upcast (bottom to surface) is within 1% of the standard mean velocity determined by 9-11 point measurements; (2) if the transit velocity is less than 25% of the mean velocity, then average error in the mean velocity is 4% or less. The major source of bias error is a result of mounting the current meter above a sounding weight and sometimes above a suspended-sediment sampling bottle, which prevents measurement of the velocity all the way to the bottom. The measured mean velocity is slightly larger than the true mean velocity. This bias error in the discharge is largest in shallow water (approximately 8% for the Missouri River at Hermann, MO, where the mean depth was 4.3 m) and smallest in deeper water (approximately 3% for the Mississippi River at Vickbsurg, MS, where the mean depth was 14.5 m). The major source of random error in the discharge is the natural

  14. Groundwater discharge mapping at Altnabreac by thermal infrared linescan surveying

    International Nuclear Information System (INIS)

    Brereton, N.R.; Hall, D.H.

    1983-07-01

    A thermal infra-red linescan survey has been carried out of the area around Altnabreac, Caithness. The objectives of the survey were: to assess the applicability of the technique to the location of springs discharging from peat covered crystalline rocks; to provide the locations of springs for a subsequent geochemical sampling programme; and to gain clearer understanding of the ground water circulation patterns in the area. The number and distribution of springs located by the survey has proved to be far greater than had been previously anticipated and the capabilities of the technique have been clearly demonstrated. The results, together with other geochemical and hydrogeological data, indicate that the majority of the springs represent near surface recent groundwaters circulating within the moraine deposits and weathered granite. (author)

  15. Thermal management of batteries

    Science.gov (United States)

    Gibbard, H. F.; Chen, C.-C.

    Control of the internal temperature during high rate discharge or charge can be a major design problem for large, high energy density battery systems. A systematic approach to the thermal management of such systems is described for different load profiles based on: thermodynamic calculations of internal heat generation; calorimetric measurements of heat flux; analytical and finite difference calculations of the internal temperature distribution; appropriate system designs for heat removal and temperature control. Examples are presented of thermal studies on large lead-acid batteries for electrical utility load levelling and nickel-zinc and lithium-iron sulphide batteries for electric vehicle propulsion.

  16. Food and feeding of juvenile chinook salmon in the central Columbia River in relation to thermal discharges and other environmental features

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C.D. [Pacific Northwest Labs., Richland, WA (United States). Ecosystems Dept.

    1970-08-01

    The relationship of thermal discharges from operating Hanford reactors to food and feeding of juvenile chinook salmon (Oncorhynchus tshawytscha) in the central Columbia River, Washington was studied in 1968 and 1969. The primary objectives were to (1) evaluate the food composition and feeding activities of the fish and (2) determine if heated effluents influenced their welfare. Environmental conditions (seasonal changes in river temperatures and flow volumes) in relation to thermal requirements of young chinook are detailed. Data on food organisms utilized by the fish in 1968 and 1969 are presented, whereas analyses for possible thermal effects are based on the more extensive 1969 data. No consistent differences attributable to thermal increments were evident. The lack of detectable effects apparently results from the fact that the main discharge plumes occur in midriver and the effluents are well mixed before reaching inshore feeding areas. The transient nature of fish at each sampling site and the availability of food organisms in the river drift are ecological factors affecting critical thermal evaluation.

  17. Using Soluble Reactive Phosphorus and Ammonia to Identify Point Source Discharge from Large Livestock Facilities

    Science.gov (United States)

    Borrello, M. C.; Scribner, M.; Chessin, K.

    2013-12-01

    A growing body of research draws attention to the negative environmental impacts on surface water from large livestock facilities. These impacts are mostly in the form of excessive nutrient loading resulting in significantly decreased oxygen levels. Over-application of animal waste on fields as well as direct discharge into surface water from facilities themselves has been identified as the main contributor to the development of hypoxic zones in Lake Erie, Chesapeake Bay and the Gulf of Mexico. Some regulators claim enforcement of water quality laws is problematic because of the nature and pervasiveness of non-point source impacts. Any direct discharge by a facility is a violation of permits governed by the Clean Water Act, unless the facility has special dispensation for discharge. Previous research by the principal author and others has shown runoff and underdrain transport are the main mechanisms by which nutrients enter surface water. This study utilized previous work to determine if the effects of non-point source discharge can be distinguished from direct (point-source) discharge using simple nutrient analysis and dissolved oxygen (DO) parameters. Nutrient and DO parameters were measured from three sites: 1. A stream adjacent to a field receiving manure, upstream of a large livestock facility with a history of direct discharge, 2. The same stream downstream of the facility and 3. A stream in an area relatively unimpacted by large-scale agriculture (control site). Results show that calculating a simple Pearson correlation coefficient (r) of soluble reactive phosphorus (SRP) and ammonia over time as well as temperature and DO, distinguishes non-point source from point source discharge into surface water. The r value for SRP and ammonia for the upstream site was 0.01 while the r value for the downstream site was 0.92. The control site had an r value of 0.20. Likewise, r values were calculated on temperature and DO for each site. High negative correlations

  18. Thermal interaction in crusted melt jets with large-scale structures

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Ken-ichiro; Sotome, Fuminori; Ishikawa, Michio [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering

    1998-01-01

    The objective of the present study is to experimentally observe thermal interaction which would be capable of triggering due to entrainment, or entrapment in crusted melt jets with `large-scale structure`. The present experiment was carried out by dropping molten zinc and molten tin of 100 grams, of which mass was sufficient to generate large-scale structures of melt jets. The experimental results show that the thermal interaction of entrapment type occurs in molten-zinc jets with rare probability, and the thermal interaction of entrainment type occurs in molten tin jets with high probability. The difference of thermal interaction between molten zinc and molten tin may attribute to differences of kinematic viscosity and melting point between them. (author)

  19. Ion flux nonuniformities in large-area high-frequency capacitive discharges

    International Nuclear Information System (INIS)

    Perret, A.; Chabert, P.; Booth, J.-P.; Jolly, J.; Guillon, J.; Auvray, Ph.

    2003-01-01

    Strong nonuniformities of plasma production are expected in capacitive discharges if the excitation wavelength becomes comparable to the reactor size (standing-wave effect) and/or if the plasma skin depth becomes comparable to the plate separation (skin effect) [M. A. Lieberman et al., Plasma Sources Sci. Technol. 11, 283 (2002)]. Ion flux uniformity measurements were carried out in a large-area square (40 cmx40 cm) capacitive discharge driven at frequencies between 13.56 MHz and 81.36 MHz in argon gas at 150 mTorr. At 13.56 MHz, the ion flux was uniform to ±5%. At 60 MHz (and above) and at low rf power, the standing-wave effect was seen (maximum of the ion flux at the center), in good quantitative agreement with theory. At higher rf power, maxima of the ion flux were observed at the edges, due either to the skin effect or to other edge effects

  20. Evaluating the Thermal Pollution Caused by Wastewaters Discharged from a Chain of Coal-Fired Power Plants along a River

    Directory of Open Access Journals (Sweden)

    Marc A. Rosen

    2015-05-01

    Full Text Available Reliable and safe operation of a coal-fired power plant is strongly linked to freshwater resources, and environmental problems related to water sources and wastewater discharge are challenges for power station operation. In this study, an evaluation on the basis of a wastewater thermal pollution vector is reported for the environmental impact of residual water generated and discharged in the Jiu River during the operation of thermoelectric units of the Rovinari, Turceni and Craiova coal-fired power plants in Romania. Wastewater thermal pollutant vector Plane Projection is applied for assessing the water temperature evolution in the water flow lane created downstream of each power plant wastewater outlet channel. Simulation on the basis of an Electricity of France model, and testing validation of the results for thermoelectric units of 330 MW of these power plants are presented.

  1. Response surface method optimization of V-shaped fin assisted latent heat thermal energy storage system during discharging process

    Directory of Open Access Journals (Sweden)

    Sina Lohrasbi

    2016-09-01

    Full Text Available Latent Heat Thermal Energy Storage Systems (LHTESS containing Phase Change Material (PCM are used to establish balance between energy supply and demand. PCMs have high latent heat but low thermal conductivity, which affects their heat transfer performance. In this paper, a novel fin array has been optimized by multi-objective Response Surface Method (RSM based on discharging process of PCM, and then this fin configuration is applied on LHTESS, and comparison between full discharging time by applying this fin array and LHTESS with other fin structures has been carried out. The employed numerical method in this paper is Standard Galerkin Finite Element Method. Adaptive grid refinement is used to solve the equations. Since the enhancement technique, which has been employed in the present study reduces the employed PCM mass, maximum energy storage capacity variations have been considered. Therefore phase change expedition and maximum energy storage capacity have been considered as the objectives of optimization and the importance of second objective is indicated which is proposed as the novelty here. Results indicate that considering maximum energy storage capacity as the objective of optimization procedure leads to efficient shape design of LHTESS. Also employing optimized V-shaped fin in LHTESS, expedites discharging process considerably in comparison with the LHTESS without fin.

  2. 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.

  3. Local and global particle and power balance in large area capacitive discharges

    International Nuclear Information System (INIS)

    Cho, Suwon; Lieberman, M A

    2003-01-01

    Large area radio frequency (rf) capacitive discharges have attracted recent interest for materials etching and deposition on large area substrates. A distinguishing feature is that the radial distribution of the absorbed rf power in these discharges depends on the rf voltage across the plates, independent of the radial variation of the plasma density n(r). A reduced set of steady-state fluid equations has been used to investigate the radial variation of n and electron temperature T e . The derived equations are shown to be invariant with respect to pL and pR, where p is the pressure, L is the plate separation and R is the discharge radius, and can be further reduced to the equations of the usual global balance model when R ε , the energy relaxation length. In this limit, the ionization frequency and T e are essentially independent of radius and n can be approximately described by the usual radial profile of a zeroth-order Bessel function. When R≥λ ε , n and T e are predominantly determined by local particle and power balance, and the n and T e radial profiles are flat over most of the volume except near the radial boundary, where n falls and T e rises to account for the increased losses at the boundary. The scale length of the edge density variation in the local balance regime is shown to be proportional to the energy relaxation length

  4. Measuring the Thermal Conductivity of Sediments for the Estimation of Groundwater Discharge to Surface Waters with Temperature Probes

    Science.gov (United States)

    Duque, C.; Müller, S.; Sebok, E.; Engesgaard, P. K.

    2015-12-01

    Using temperature probes is a common exploratory method for studying groundwater-surface water interaction due to the ease for collecting measurements and the simplicity of the different analytical solutions. This approach requires to define the surface water temperature, the groundwater temperature and a set of parameters (density and specific capacity of water, and thermal conductivity of sediments) that can be easily extracted from tabulated values under the assumption that they are homogeneous in the study area. In the case of the thermal conductivity, it is common to apply a standard value of 1.84 Wm-1 C-1 corresponding to sand. Nevertheless the environments where this method is applied, like streambeds or lake/lagoons shores, are sedimentary depositional systems with high energy and biological activity that often lead to sediments dominated by organic matter or sharp changes in grain size modifying greatly the thermal conductivity values. In this study, the thermal conductivity was measured in situ along transects where vertical temperature profiles were collected in a coastal lagoon bed receiving groundwater discharge (Ringkøbing Fjord, Denmark). A set of 4 transects with 10-20 temperature profiles during 3 different seasons was analyzed together with more than 150 thermal conductivity measurements along the working transects and in experimental parcels of 1 m2 where the cm scale spatial variability of the thermal conductivity was assessed. The application of a literature-based bulk thermal conductivity of 1.84 Wm-1 C-1 instead of field data that ranged from 0.62 to 2.19 Wm-1 C-1, produced a mean flux overestimation of 2.33 cm d-1 that, considering the low fluxes of the study area, represents an increase of 89 % and up to a factor of 3 in the most extreme cases. The changes in thermal conductivity can alter the estimated fluxes hindering the detection of patterns in groundwater discharge and modifying the interpretation of the results.

  5. Thermocapillary Bubble Migration: Thermal Boundary Layers for Large Marangoni Numbers

    Science.gov (United States)

    Balasubramaniam, R.; Subramanian, R. S.

    1996-01-01

    The migration of an isolated gas bubble in an immiscible liquid possessing a temperature gradient is analyzed in the absence of gravity. The driving force for the bubble motion is the shear stress at the interface which is a consequence of the temperature dependence of the surface tension. The analysis is performed under conditions for which the Marangoni number is large, i.e. energy is transferred predominantly by convection. Velocity fields in the limit of both small and large Reynolds numbers are used. The thermal problem is treated by standard boundary layer theory. The outer temperature field is obtained in the vicinity of the bubble. A similarity solution is obtained for the inner temperature field. For both small and large Reynolds numbers, the asymptotic values of the scaled migration velocity of the bubble in the limit of large Marangoni numbers are calculated. The results show that the migration velocity has the same scaling for both low and large Reynolds numbers, but with a different coefficient. Higher order thermal boundary layers are analyzed for the large Reynolds number flow field and the higher order corrections to the migration velocity are obtained. Results are also presented for the momentum boundary layer and the thermal wake behind the bubble, for large Reynolds number conditions.

  6. Very large thermal rectification in bulk composites consisting partly of icosahedral quasicrystals

    International Nuclear Information System (INIS)

    Takeuchi, Tsunehiro

    2014-01-01

    The bulk thermal rectifiers usable at a high temperature above 300 K were developed by making full use of the unusual electron thermal conductivity of icosahedral quasicrystals. The unusual electron thermal conductivity was caused by a synergy effect of quasiperiodicity and by a narrow pseudogap at the Fermi level. The rectification ratio, defined by TRR = |J large |/|J small |, reached vary large values exceeding 2.0. This significant thermal rectification would lead to new practical applications for the heat management. (paper)

  7. High speed imaging, lightning mapping arrays and thermal imaging: a synergy for the monitoring of electrical discharges at the onset of volcanic explosions

    Science.gov (United States)

    Gaudin, Damien; Cimarelli, Corrado; Behnke, Sonja; Cigala, Valeria; Edens, Harald; McNutt, Stefen; Smith, Cassandra; Thomas, Ronald; Van Eaton, Alexa

    2017-04-01

    Volcanic lightning is being increasingly studied, due to its great potential for the detection and monitoring of ash plumes. Indeed, it is observed in a large number of ash-rich volcanic eruptions and it produces electromagnetic waves that can be detected remotely in all weather conditions. Electrical discharges in volcanic plume can also significantly change the structural, chemical and reactivity properties of the erupted material. Although electrical discharges are detected in various regions of the plume, those happening at the onset of an explosion are of particular relevance for the early warning and the study of volcanic jet dynamics. In order to better constrain the electrical activity of young volcanic plumes, we deployed at Sakurajima (Japan) in 2015 a multiparametric set-up including: i) a lightning mapping array (LMA) of 10 VHF antennas recording the electromagnetic waves produced by lightning at a sample rate of 25 Msps; ii) a visible-light high speed camera (5000 frames per second, 0.5 m pixel size, 300 m field of view) shooting short movies (approx. duration 1 s) at different stages of the plume evolution, showing the location of discharges in relation to the plume; and iii) a thermal camera (25 fps, 1.5 m pixel size, 800 m field of view) continuously recording the plume and allowing the estimation of its main source parameters (volume, rise velocity, mass eruption rate). The complementarity of these three setups is demonstrated by comparing and aggregating the data at various stages of the plume development. In the earliest stages, the high speed camera spots discrete small discharges, that appear on the LMA data as peaks superimposed to the continuous radio frequency (CRF) signal. At later stages, flashes happen less frequently and increase in length. The correspondence between high speed camera and LMA data allows to define a direct correlation between the length of the flash and the intensity of the electromagnetic signal. Such correlation is

  8. Pulsed high voltage electric discharge disinfection of microbially contaminated liquids.

    Science.gov (United States)

    Anpilov, A M; Barkhudarov, E M; Christofi, N; Kop'ev, V A; Kossyi, I A; Taktakishvili, M I; Zadiraka, Y

    2002-01-01

    To examine the use of a novel multielectrode slipping surface discharge (SSD) treatment system, capable of pulsed plasma discharge directly in water, in killing micro-organisms. Potable water containing Escherichia coli and somatic coliphages was treated with pulsed electric discharges generated by the SSD. The SSD system was highly efficient in the microbial disinfection of water with a low energy utilization (eta approximately 10-4 kW h l-1). The SSD treatment was effective in the destruction of E. coli and its coliphages through the generation of u.v. radiation, ozone and free radicals. The non-thermal treatment method can be used for the eradication of micro-organisms in a range of contaminated liquids, including milk, negating the use of pasteurization. The method utilizes multipoint electric discharges capable of treating large volumes of liquid under static and flowing regimes.

  9. Measurements of plasma termination in ICRF heated long pulse discharges with fast framing cameras in the Large Helical Device

    International Nuclear Information System (INIS)

    Shoji, Mamoru; Kasahara, Hiroshi; Tanaka, Hirohiko

    2015-01-01

    The termination process of long pulse plasma discharges in the Large Helical Device (LHD) have been observed with fast framing cameras, which shows that the reason for the termination of the discharged has been changed with increased plasma heating power, improvements of plasma heating systems and change of the divertor configuration, etc. For long pulse discharges in FYs2010-2012, the main reason triggering the plasma termination was reduction of ICRF heating power with rise of iron ion emission due to electric breakdown in an ICRF antenna. In the experimental campaign in FY2013, the duration time of ICRF heated long pulse plasma discharges has been extended to about 48 minutes with a plasma heating power of ∼1.2 MW and a line-averaged electron density of ∼1.2 × 10"1"9 m"-"3. The termination of the discharges was triggered by release of large amounts of carbon dusts from closed divertor regions, indicating that the control of dust formation in the divertor regions is indispensable for extending the duration time of long pulse discharges. (author)

  10. 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.

  11. Delineation of thermal effluents discharged into tropical waters around Puerto Rico by aerial infrared scanning

    International Nuclear Information System (INIS)

    Wood, E.D.

    1975-01-01

    Aerial infrared scanning offers a versatile tool with which to monitor thermal discharges and a rapid method of detecting extraneous discharges, whose temperatures differ from the ambient waters. Knowledge of the extent and distribution of thermal effluents is necessary to assist in determining the effects of the added heat upon biota of the region. An AGA Model 680 Thermovision infrared scanner with a 45 0 lens was mounted in a Cessna 182, and flown at altitudes of 600 to 2000 m during night and twilight hours. The detector was InSb, cooled with liquid nitrogen and sensitive to the range 2 to 5.6 μm. The picture was originally displayed on a color monitor which assigned ten arbitrary colors to shades of gray on the control unit. Isotherms have been assigned using coincidental surface measurements made with a thermometer, read to the nearest 0.1 0 C. The data were then recorded on film. Ranges were set at 2 0 C and 5 0 C, common sensitivities were 0.2 0 C and 0.5 0 C, respectively. More recently, the data have been recorded on magnetic tapes with a Sabre III instrumentation tape recorder. Observed data have been compared to predictions made using the Pritchard Plume Model. Anomalies can be explained by boundary, wind, and tidal effects. (U.S.)

  12. A systematic approach for electrochemical-thermal modelling of a large format lithium-ion battery for electric vehicle application

    Science.gov (United States)

    Hosseinzadeh, Elham; Genieser, Ronny; Worwood, Daniel; Barai, Anup; Marco, James; Jennings, Paul

    2018-04-01

    A 1D electrochemical-thermal model is developed to characterise the behaviour of a 53 Ah large format pouch cell with LiNixMnyCo1-x-yO2 (NMC) chemistry over a wide range of operating conditions, including: continuous charge (0.5C-2C), continuous discharge (0.5C-5C) and operation of the battery within an electric vehicle (EV) over an urban drive-cycle (WLTP Class 3) and for a high performance EV being driven under track racing conditions. The 1D model of one electrode pair is combined with a 3D thermal model of a cell to capture the temperature distribution at the cell scale. Performance of the model is validated for an ambient temperature range of 5 °C-45 °C. Results highlight that battery performance is highly dependent on ambient temperature. By decreasing the ambient temperature from 45 °C to 5 °C, the available energy drops by 17.1% and 7.8% under 0.5C and 5C discharge respectively. Moreover, the corresponding power loss is found to be: 5.23% under the race cycle as compared with 7.57% under the WLTP drive cycle. Formulation of the model is supported by a comprehensive set of experiments, for quantifying key parameters and for model validation. The full parameter-set for the model is provided ensuring the model is a valuable resource to underpin further research.

  13. Prediction of Thermal Environment in a Large Space Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Yoon

    2018-02-01

    Full Text Available Since the thermal environment of large space buildings such as stadiums can vary depending on the location of the stands, it is important to divide them into different zones and evaluate their thermal environment separately. The thermal environment can be evaluated using physical values measured with the sensors, but the occupant density of the stadium stands is high, which limits the locations available to install the sensors. As a method to resolve the limitations of installing the sensors, we propose a method to predict the thermal environment of each zone in a large space. We set six key thermal factors affecting the thermal environment in a large space to be predicted factors (indoor air temperature, mean radiant temperature, and clothing and the fixed factors (air velocity, metabolic rate, and relative humidity. Using artificial neural network (ANN models and the outdoor air temperature and the surface temperature of the interior walls around the stands as input data, we developed a method to predict the three thermal factors. Learning and verification datasets were established using STAR CCM+ (2016.10, Siemens PLM software, Plano, TX, USA. An analysis of each model’s prediction results showed that the prediction accuracy increased with the number of learning data points. The thermal environment evaluation process developed in this study can be used to control heating, ventilation, and air conditioning (HVAC facilities in each zone in a large space building with sufficient learning by ANN models at the building testing or the evaluation stage.

  14. Kinetic study on non-thermal volumetric plasma decay in the early afterglow of air discharge generated by a short pulse microwave or laser

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wei, E-mail: yangwei861212@126.com; Zhou, Qianhong; Dong, Zhiwei [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

    2016-08-28

    This paper reports a kinetic study on non-thermal plasma decay in the early afterglow of air discharge generated by short pulse microwave or laser. A global self-consistent model is based on the particle balance of complex plasma chemistry, electron energy equation, and gas thermal balance equation. Electron-ion Coulomb collision is included in the steady state Boltzmann equation solver to accurately describe the electron mobility and other transport coefficients. The model is used to simulate the afterglow of microsecond to nanosecond pulse microwave discharge in N{sub 2}, O{sub 2}, and air, as well as femtosecond laser filament discharge in dry and humid air. The simulated results for electron density decay are in quantitative agreement with the available measured ones. The evolution of plasma decay under an external electric field is also investigated, and the effect of gas heating is considered. The underlying mechanism of plasma density decay is unveiled through the above kinetic modeling.

  15. Recent developments in large-scale ozone generation with dielectric barrier discharges

    Science.gov (United States)

    Lopez, Jose L.

    2014-10-01

    Large-scale ozone generation for industrial applications has been entirely based on the creation of microplasmas or microdischarges created using dielectric barrier discharge (DBD) reactors. Although versions of DBD generated ozone have been in continuous use for over a hundred years especially in water treatment, recent changes in environmental awareness and sustainability have lead to a surge of ozone generating facilities throughout the world. As a result of this enhanced global usage of this environmental cleaning application various new discoveries have emerged in the science and technology of ozone generation. This presentation will describe some of the most recent breakthrough developments in large-scale ozone generation while further addressing some of the current scientific and engineering challenges of this technology.

  16. Experimental Study of Thermal Runaway Process of 18650 Lithium-Ion Battery

    Directory of Open Access Journals (Sweden)

    Jingjing Liu

    2017-02-01

    Full Text Available This study addresses the effects of the SOC (State of Charge and the charging–discharging process on the thermal runaway of 18650 lithium-ion batteries. A series of experiments were conducted on an electric heating and testing apparatus. The experimental results indicate that 6 W is the critical heating power for 40% SOC. With a 20 W constant heating rate, the thermal runaway initial temperature of the lithium-ion battery decreases with the increasing SOC. The final thermal runaway temperature increases with the SOC when the SOC is lower than 80%. However, a contrary conclusion was obtained when the SOC was higher than 80%. Significant mass loss, accompanied by an intense exothermic reaction, took place under a higher SOC. The critical charging current, beyond which the thermal runaway occurs, was found to be 2.6 A. The thermal runaway initial temperature decreases with the increasing charging current, while the intensity of the exothermic reaction varies inversely. Mass ejection of gas and electrolytes exists during thermal runaway when the charging current is higher than 10.4 A, below which only a large amount of gas is released. The thermal runaway initial temperature of discharging is higher than that of non-discharging.

  17. Experimental Study of Thermal Runaway Process of 18650 Lithium-Ion Battery.

    Science.gov (United States)

    Liu, Jingjing; Wang, Zhirong; Gong, Junhui; Liu, Kai; Wang, Hao; Guo, Linsheng

    2017-02-25

    This study addresses the effects of the SOC (State of Charge) and the charging-discharging process on the thermal runaway of 18650 lithium-ion batteries. A series of experiments were conducted on an electric heating and testing apparatus. The experimental results indicate that 6 W is the critical heating power for 40% SOC. With a 20 W constant heating rate, the thermal runaway initial temperature of the lithium-ion battery decreases with the increasing SOC. The final thermal runaway temperature increases with the SOC when the SOC is lower than 80%. However, a contrary conclusion was obtained when the SOC was higher than 80%. Significant mass loss, accompanied by an intense exothermic reaction, took place under a higher SOC. The critical charging current, beyond which the thermal runaway occurs, was found to be 2.6 A. The thermal runaway initial temperature decreases with the increasing charging current, while the intensity of the exothermic reaction varies inversely. Mass ejection of gas and electrolytes exists during thermal runaway when the charging current is higher than 10.4 A, below which only a large amount of gas is released. The thermal runaway initial temperature of discharging is higher than that of non-discharging.

  18. Thermal anchoring of wires in large scale superconducting coil test experiment

    International Nuclear Information System (INIS)

    Patel, Dipak; Sharma, A.N.; Prasad, Upendra; Khristi, Yohan; Varmora, Pankaj; Doshi, Kalpesh; Pradhan, S.

    2013-01-01

    Highlights: • We addressed how thermal anchoring in large scale coil test is different compare to small cryogenic apparatus? • We did precise estimation of thermal anchoring length at 77 K and 4.2 K heat sink in large scale superconducting coil test experiment. • We addressed, the quality of anchoring without covering entire wires using Kapton/Teflon tape. • We obtained excellent results in temperature measurement without using GE Varnish by doubling estimated anchoring length. -- Abstract: Effective and precise thermal anchoring of wires in cryogenic experiment is mandatory to measure temperature in milikelvin accuracy and to avoid unnecessary cooling power due to additional heat conduction from room temperature (RT) to operating temperature (OT) through potential, field, displacement and stress measurement instrumentation wires. Instrumentation wires used in large scale superconducting coil test experiments are different compare to cryogenic apparatus in terms of unique construction and overall diameter/area due to errorless measurement in large time-varying magnetic field compare to small cryogenic apparatus, often shielded wires are used. Hence, along with other variables, anchoring techniques and required thermal anchoring length are entirely different in this experiment compare to cryogenic apparatus. In present paper, estimation of thermal anchoring length of five different types of instrumentation wires used in coils test campaign at Institute for Plasma Research (IPR), India has been discussed and some temperature measurement results of coils test campaign have been presented

  19. Discharge lamp technologies

    Science.gov (United States)

    Dakin, James

    1994-01-01

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advances.

  20. A novel technique to monitor thermal discharges using thermal infrared imaging.

    Science.gov (United States)

    Muthulakshmi, A L; Natesan, Usha; Ferrer, Vincent A; Deepthi, K; Venugopalan, V P; Narasimhan, S V

    2013-09-01

    Coastal temperature is an important indicator of water quality, particularly in regions where delicate ecosystems sensitive to water temperature are present. Remote sensing methods are highly reliable for assessing the thermal dispersion. The plume dispersion from the thermal outfall of the nuclear power plant at Kalpakkam, on the southeast coast of India, was investigated from March to December 2011 using thermal infrared images along with field measurements. The absolute temperature as provided by the thermal infrared (TIR) images is used in the Arc GIS environment for generating a spatial pattern of the plume movement. Good correlation of the temperature measured by the TIR camera with the field data (r(2) = 0.89) make it a reliable method for the thermal monitoring of the power plant effluents. The study portrays that the remote sensing technique provides an effective means of monitoring the thermal distribution pattern in coastal waters.

  1. Experimental investigation on large-area dielectric barrier discharge in atmospheric nitrogen and air assisted by the ultraviolet lamp.

    Science.gov (United States)

    Zhang, Yan; Gu, Biao; Wang, Wenchun; Wang, Dezhen; Peng, Xuwen

    2009-04-01

    In this paper, ultraviolet radiation produced by the ultraviolet lamp is employed to supply pre-ionization for the dielectric barrier discharge in N(2) or air at atmospheric pressure. The effect of the ultraviolet pre-ionization on improving the uniformity of the dielectric barrier discharge is investigated experimentally. The atmospheric pressure glow discharge of the large area (270 mm x 120 mm) is obtained successfully via the ultraviolet pre-ionization in atmospheric DBD in N(2) when the gas gap decrease to 3mm. Based on the emission spectra, the mechanism which ultraviolet pre-ionization improves the uniformity of the dielectric barrier discharge is discussed.

  2. Discharge residence of TLD tagged fish

    International Nuclear Information System (INIS)

    Romberg, G.P.; Prepejchal, W.

    1974-01-01

    Although visual observations suggested that fish remained in the discharge for considerable periods, temperature-sensitive tags indicated the majority of fish spend less than 50 hr or 10 percent of the time at discharge temperatures. During 1974 a second fish tagging study was conducted, using temperature-sensitive tags to yield discharge residence times of Lake Michigan salmonids at Point Beach thermal discharge. Preliminary results revealed that many fish tag values were close to Unit I line indicating that calculated maximum discharge residence times for these fish will be nearly 100 percent of the elapsed time

  3. Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species.

    Science.gov (United States)

    Arjunan, Krishna Priya; Friedman, Gary; Fridman, Alexander; Clyne, Alisa Morss

    2012-01-07

    Vascularization plays a key role in processes such as wound healing and tissue engineering. Non-thermal plasma, which primarily produces reactive oxygen species (ROS), has recently emerged as an efficient tool in medical applications including blood coagulation, sterilization and malignant cell apoptosis. Liquids and porcine aortic endothelial cells were treated with a non-thermal dielectric barrier discharge plasma in vitro. Plasma treatment of phosphate-buffered saline (PBS) and serum-free medium increased ROS concentration in a dose-dependent manner, with a higher concentration observed in serum-free medium compared with PBS. Species concentration inside cells peaked 1 h after treatment, followed by a decrease 3 h post treatment. Endothelial cells treated with a plasma dose of 4.2 J cm(-2) had 1.7 times more cells than untreated samples 5 days after plasma treatment. The 4.2 J cm(-2) plasma dose increased two-dimensional migration distance by 40 per cent compared with untreated control, while the number of cells that migrated through a three-dimensional collagen gel increased by 15 per cent. Tube formation was also enhanced by plasma treatment, with tube lengths in plasma-treated samples measuring 2.6 times longer than control samples. A fibroblast growth factor-2 (FGF-2) neutralizing antibody and ROS scavengers abrogated these angiogenic effects. These data indicate that plasma enhanced proliferation, migration and tube formation is due to FGF-2 release induced by plasma-produced ROS. Non-thermal plasma may be used as a potential tool for applying ROS in precise doses to enhance vascularization.

  4. 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.

  5. A thermal packed-bed reactor and a silent discharge plasma cell for a two-stage treatment system

    International Nuclear Information System (INIS)

    Godoy-Cabrera, O G; Lopez-Callejas, R; Mercado-Cabrera, A; Barocio, S R; Valencia, R; Munoz-Castro, A; Eguiluz, R Pena; Piedad-Beneitez, A de la

    2006-01-01

    Dielectric barrier discharge cells (DBDCs) have proved their efficiency in the generation of cold plasmas for hazardous organic compound degradation. Here, we describe the design and construction of a dual thermal packed-bed reactor and DBDC-based system to carry out the degradation of hazardous organic compounds in both liquid and gas phases. The main components of this system are: (i) the thermal treatment system (ii) DBDC and (iii) resonant inverters of low (3.3 kHz) and high (100 kHz) calculated frequencies. The definition of the cell physical parameters considers: (a) a first-order degradation ratio of the compound and (b) the air breakdown at atmospheric pressure as a function of the transport carrier gas. The power consumed by the cells during the discharges was computed theoretically and experimentally. Using the dual system along with a gas chromatography diagnostic system, highly efficient degradations of a test compound (benzene) have been obtained, reaching 99.950% in the case of a cell experimentally operated at 3.3 kHz and up to 99.996% in another one at 94.3 kHz. An additional 3.7 times reduction in the latter case residence time with respect to the low frequency cell has been found

  6. Direct analysis of anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption-dielectric barrier discharge ionization mass spectrometry.

    Science.gov (United States)

    Saha, Subhrakanti; Mandal, Mridul Kanti; Nonami, Hiroshi; Hiraoka, Kenzo

    2014-08-11

    Rapid detection of trace level anabolic steroids in urine is highly desirable to monitor the consumption of performance enhancing anabolic steroids by athletes. The present article describes a novel strategy for identifying the trace anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption (LPTD) coupled to dielectric barrier discharge (DBD) ionization mass spectrometry. Using this method the steroid molecules are enriched within a liquid droplet during the thermal desorption process and desorbed all-together at the last moment of droplet evaporation in a short time domain. The desorbed molecules were ionized using a dielectric barrier discharge ion-source in front of the mass spectrometer inlet at open atmosphere. This process facilitates the sensitivity enhancement with several orders of magnitude compared to the thermal desorption at a lower temperature. The limits of detection (LODs) of various steroid molecules were found to be in the range of 0.05-0.1 ng mL(-1) for standard solutions and around two orders of magnitude higher for synthetic urine samples. The detection limits of urinary anabolic steroids could be lowered by using a simple and rapid dichloromethane extraction technique. The analytical figures of merit of this technique were evaluated at open atmosphere using suitable internal standards. The technique is simple and rapid for high sensitivity and high throughput screening of anabolic steroids in urine. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Studies of thermal energy confinement scaling in PDX plasmas: D0 → H+ limiter discharges

    International Nuclear Information System (INIS)

    Kaye, S.M.; Goldston, R.J.; Bell, M.

    1984-06-01

    Experiments were performed on the PDX tokamak to study plasma heating and β scaling with higher power, near-perpendicular neutral beam injection. The data taken during these experiments were analyzed using a time-dependent data interpretation code (TRANSP) to study the transport and thermal confinement scaling over a wide range of plasma parameters. This study focuses on results from experiments with D 0 injection into H + plasmas using graphite rail limiters, a = 40 to 44 cm, R = 143 cm, I/sub p/ = 200 to 480 kA, B/sub T/ = 0.7 to 2.2 T, and typically anti n/sub e/ = 2.5 to 4.2 x 10 13 cm -3 . The results of this study indicate that for both ohmic and neutral beam heated discharges the energy flow out of the plasma is dominated by anomalous electron losses, attributed to electron thermal conduction. The ion conduction losses are well described to electron thermal conduction. The ion conduction losses are well described by neoclassical theory; however, the total ion loss influences the power balance significantly only at high toroidal fields and high plasma currents

  8. Reduction of ion thermal diffusivity associated with the transition of the radial electric field in neutral-beam-heated plasmas in the large helical device.

    Science.gov (United States)

    Ida, K; Funaba, H; Kado, S; Narihara, K; Tanaka, K; Takeiri, Y; Nakamura, Y; Ohyabu, N; Yamazaki, K; Yokoyama, M; Murakami, S; Ashikawa, N; deVries, P C; Emoto, M; Goto, M; Idei, H; Ikeda, K; Inagaki, S; Inoue, N; Isobe, M; Itoh, K; Kaneko, O; Kawahata, K; Khlopenkov, K; Komori, A; Kubo, S; Kumazawa, R; Liang, Y; Masuzaki, S; Minami, T; Miyazawa, J; Morisaki, T; Morita, S; Mutoh, T; Muto, S; Nagayama, Y; Nakanishi, H; Nishimura, K; Noda, N; Notake, T; Kobuchi, T; Ohdachi, S; Ohkubo, K; Oka, Y; Osakabe, M; Ozaki, T; Pavlichenko, R O; Peterson, B J; Sagara, A; Saito, K; Sakakibara, S; Sakamoto, R; Sanuki, H; Sasao, H; Sasao, M; Sato, K; Sato, M; Seki, T; Shimozuma, T; Shoji, M; Suzuki, H; Sudo, S; Tamura, N; Toi, K; Tokuzawa, T; Torii, Y; Tsumori, K; Yamamoto, T; Yamada, H; Yamada, I; Yamaguchi, S; Yamamoto, S; Yoshimura, Y; Watanabe, K Y; Watari, T; Hamada, Y; Motojima, O; Fujiwara, M

    2001-06-04

    Recent large helical device experiments revealed that the transition from ion root to electron root occurred for the first time in neutral-beam-heated discharges, where no nonthermal electrons exist. The measured values of the radial electric field were found to be in qualitative agreement with those estimated by neoclassical theory. A clear reduction of ion thermal diffusivity was observed after the mode transition from ion root to electron root as predicted by neoclassical theory when the neoclassical ion loss is more dominant than the anomalous ion loss.

  9. A Review of Control Strategy of the Large-scale of Electric Vehicles Charging and Discharging Behavior

    Science.gov (United States)

    Kong, Lingyu; Han, Jiming; Xiong, Wenting; Wang, Hao; Shen, Yaqi; Li, Ying

    2017-05-01

    Large scale access of electric vehicles will bring huge challenges to the safe operation of the power grid, and it’s important to control the charging and discharging of the electric vehicle. First of all, from the electric quality and network loss, this paper points out the influence on the grid caused by electric vehicle charging behaviour. Besides, control strategy of electric vehicle charging and discharging has carried on the induction and the summary from the direct and indirect control. Direct control strategy means control the electric charging behaviour by controlling its electric vehicle charging and discharging power while the indirect control strategy by means of controlling the price of charging and discharging. Finally, for the convenience of the reader, this paper also proposed a complete idea of the research methods about how to study the control strategy, taking the adaptability and possibility of failure of electric vehicle control strategy into consideration. Finally, suggestions on the key areas for future research are put up.

  10. A combined geochemical and isotopic study of the fluids discharged from the Montecatini thermal system (NW Tuscany, Italy)

    International Nuclear Information System (INIS)

    Capecchiacci, F.; Tassi, F.; Vaselli, O.; Bicocchi, G.; Cabassi, J.; Giannini, L.; Nisi, B.; Chiocciora, G.

    2015-01-01

    Highlights: • Water chemistry of the Montecatini thermal system (MTS) indicates a Na–Cl composition. • Dissolved gases are dominated by a CO 2 -rich gas phase. • MTS is fed by meteoric waters with a relatively long (>50 years) circulation. • Geothermometric estimations suggest that the fluid reservoir is at T ⩾ 80–90 °C. • A new conceptual model of fluid circulation was proposed for MTS. - Abstract: The thermo-mineral fluids discharges of Montecatini Terme (Northern Apennines, Tuscany, Italy) have been exploited since the Roman times and despite the fact that this thermal complex is one of the biggest in Europe, the most recent geochemical investigations were published almost 40 years ago. To fill this gap, in this paper a detailed geochemical and isotopic investigation on the main thermal springs and wells from the Montecatini thermal system (MTS) is presented. The chemical and isotopic features of the Montecatini waters suggested that they are mainly controlled by water–rock interaction processes between meteoric water, permeating at depth from the surrounding reliefs (up to 800 m a.s.l.), and the Triassic evaporites (Burano Formation) belonging to the Tuscan sedimentary series. The local stratigraphic and tectonic framework favors an efficient recharge of the hydrothermal reservoir by the meteoric precipitation from a large catchment area and this aspect plays a fundamental role for the longevity of the Montecatini thermal spas, notwithstanding the huge amount of thermal water exploited. The 3 H values indicated that the thermal waters are likely related to a relatively long (>50 years) fluid circulation pattern. Approaching the surface, thermal and saline waters mix with cold and low TDS (Total Dissolved Solids) waters hosted in short, shallow aquifer(s), whose chemistry is dictated by the interaction of rain waters with silico-clastic rocks of low solubility. Geothermometric estimations in the F − –SO 4 2− –HCO 3 − system suggested

  11. Coupled large-eddy simulation of thermal mixing in a T-junction

    International Nuclear Information System (INIS)

    Kloeren, D.; Laurien, E.

    2011-01-01

    Analyzing thermal fatigue due to thermal mixing in T-junctions is part of the safety assessment of nuclear power plants. Results of two large-eddy simulations of mixing flow in a T-junction with coupled and adiabatic boundary condition are presented and compared. The temperature difference is set to 100 K, which leads to strong stratification of the flow. The main and the branch pipe intersect horizontally in this simulation. The flow is characterized by steady wavy pattern of stratification and temperature distribution. The coupled solution approach shows highly reduced temperature fluctuations in the near wall region due to thermal inertia of the wall. A conjugate heat transfer approach is necessary in order to simulate unsteady heat transfer accurately for large inlet temperature differences. (author)

  12. Thermal Pollution Math Model. Volume 1. Thermal Pollution Model Package Verification and Transfer. [environment impact of thermal discharges from power plants

    Science.gov (United States)

    Lee, S. S.; Sengupta, S.

    1980-01-01

    Two three dimensional, time dependent models, one free surface, the other rigid lid, were verified at Anclote Anchorage and Lake Keowee respectively. The first site is a coastal site in northern Florida; the other is a man-made lake in South Carolina. These models describe the dispersion of heated discharges from power plants under the action of ambient conditions. A one dimensional, horizontally-averaged model was also developed and verified at Lake Keowee. The data base consisted of archival in situ measurements and data collected during field missions. The field missions were conducted during winter and summer conditions at each site. Each mission consisted of four infrared scanner flights with supporting ground truth and in situ measurements. At Anclote, special care was taken to characterize the complete tidal cycle. The three dimensional model results compared with IR data for thermal plumes on an average within 1 C root mean square difference. The one dimensional model performed satisfactorily in simulating the 1971-1979 period.

  13. Thermal band image processing on the warm water discharges of nuclear power plants and the drifting of Echizen-Jellyfishes by using terra/aqua-MODIS data

    International Nuclear Information System (INIS)

    Kato, Yoshinobu; Fujita, Yusuke

    2005-01-01

    At the Awara campus (lat. 36.264degN, long, 136.235degE) of Fukui University of Technology, a Terra/Aqua-MODIS receiving system is operated from September, 2003. This paper deals with the thermal band image processing by using the received MODIS data. In chapter 2, we investigate the image representation of the warm water discharges of nuclear power plants located with Wakasa Bay of Fukui Prefecture. In chapter 3, we describe the image processing of the drifting of Echizen-Jellyfishes. The Echizen-Jellyfish, a kind of big jellyfish, whose scientific name is Nemopilema nomurai Kishinouye, appeared in large quantities in 2003 and did serious damage to the fishery in Japan Sea. (author)

  14. Beam-plasma discharge in a Kyoto beam-plasma-ion source

    International Nuclear Information System (INIS)

    Ishikawa, J.; Takagi, T.

    1983-01-01

    A beam-plasma type ion source employing an original operating principle has been developed by the present authors. The ion source consists of an ion extraction region with an electron gun, a thin long drift tube as the plasma production chamber, and a primary electron beam collector. An electron beam is effectively utilized for the dual purpose of high density plasma production as a result of beam-plasma discharge, and high current ion beam extraction with ion space-charge compensation. A high density plasma of the order of 10 11 --10 13 cm -3 was produced by virtue of the beam-plasma discharge which was caused by the interaction between a space-charge wave on the electron beam and a high frequency plasma wave. The plasma density then produced was 10 2 --10 3 times the density produced only by collisional ionization by the electron beam. In order to obtain a stable beam-plasma discharge, a secondary electron beam emitted from the electron collector should be utilized. The mechanism of the beam-plasma discharge was analyzed by use of a linear theory in the case of the small thermal energy of the electron beam, and by use of a quasilinear theory in the case of the large thermal energy. High current ion beams of more than 0.1 A were extracted even at a low extraction voltage of 1--5 kV

  15. Extracting Prior Distributions from a Large Dataset of In-Situ Measurements to Support SWOT-based Estimation of River Discharge

    Science.gov (United States)

    Hagemann, M.; Gleason, C. J.

    2017-12-01

    The upcoming (2021) Surface Water and Ocean Topography (SWOT) NASA satellite mission aims, in part, to estimate discharge on major rivers worldwide using reach-scale measurements of stream width, slope, and height. Current formalizations of channel and floodplain hydraulics are insufficient to fully constrain this problem mathematically, resulting in an infinitely large solution set for any set of satellite observations. Recent work has reformulated this problem in a Bayesian statistical setting, in which the likelihood distributions derive directly from hydraulic flow-law equations. When coupled with prior distributions on unknown flow-law parameters, this formulation probabilistically constrains the parameter space, and results in a computationally tractable description of discharge. Using a curated dataset of over 200,000 in-situ acoustic Doppler current profiler (ADCP) discharge measurements from over 10,000 USGS gaging stations throughout the United States, we developed empirical prior distributions for flow-law parameters that are not observable by SWOT, but that are required in order to estimate discharge. This analysis quantified prior uncertainties on quantities including cross-sectional area, at-a-station hydraulic geometry width exponent, and discharge variability, that are dependent on SWOT-observable variables including reach-scale statistics of width and height. When compared against discharge estimation approaches that do not use this prior information, the Bayesian approach using ADCP-derived priors demonstrated consistently improved performance across a range of performance metrics. This Bayesian approach formally transfers information from in-situ gaging stations to remote-sensed estimation of discharge, in which the desired quantities are not directly observable. Further investigation using large in-situ datasets is therefore a promising way forward in improving satellite-based estimates of river discharge.

  16. Characterization of the large area plane-symmetric low-pressure DC glow discharge

    Science.gov (United States)

    Avtaeva, S.; Gorokhovsky, V.; Myers, S.; Robertson, S.; Shunko, E.; Zembower, Z.

    2016-10-01

    Electron density and temperature as well as nitrogen dissociation degree in the low-pressure (10-50 mTorr) large area plane-symmetric DC glow discharge in Ar-N2 mixtures are studied by probes and spectral methods. Electron density measured by a hairpin probe is in good agreement with that derived from the intensity ratio of the N2 2nd positive system bands IC, 1 - 3/IC, 0 - 2 and from the intensity ratio of argon ions and atom lines IArII/IArI, while Langmuir probe data provides slightly higher values of electron density. Electron density in the low-pressure DC glow discharge varies with the discharge conditions in the limits of 108-1010 cm- 3. The concept of electron temperature can be used in low-pressure glow discharges with reservations. The intensity ratio of (0-0) vibrational bands of N2 1st negative and 2nd positive systems I391.4/I337.1 exhibits the electron temperature of 1.5-2.5 eV when argon fraction in the mixture is higher than nitrogen fraction and this ratio quickly increases with nitrogen fraction up to 10 eV in pure nitrogen. The electron temperature calculated from Langmuir probe I-V characteristics assuming a Maxwellian EEDF, gives Te 0.3-0.4 eV. In-depth analysis of the EEDF using the second derivative of Langmuir probe I-V characteristics shows that in a low-pressure glow discharge the EEDF is non-Maxwellian. The EEDF has two populations of electrons: the main background non-Maxwellian population of ;cold; electrons with the mean electron energy of 0.3-0.4 eV and the small Maxwellian population of ;hot; electrons with the mean electron energy of 1.0-2.5 eV. Estimations show that with electron temperature lower than 1 eV the rate of the direct electron impact ionization of N2 is low and the main mechanism of N2 ionization becomes most likely Penning and associative ionization. In this case, assumptions of the intensity ratio IN2+, 391/IN2, 337 method are violated. In the glow discharge, N2 dissociation degree reaches about 7% with the argon

  17. Thermal effluents from nuclear power plant influences species distribution and thermal tolerance of fishes in reservoirs

    International Nuclear Information System (INIS)

    Pal, A.K.; Das, T.; Dalvi, R.S.; Bagchi, S.; Manush, S.M.; Ayyappan, S.; Chandrachoodan, P.P.; Apte, S.K.; Ravi, P.M.

    2007-01-01

    During electricity generation water bodies like reservoir act as a heat sink for thermal effluent discharges from nuclear power plant. We hypothesized that the fish fauna gets distributed according to their temperature preference in the thermal gradient. In a simulated environment using critical thermal methodology (CTM), we assessed thermal tolerance and metabolic profile of fishes (Puntius filamentosus, Parluciosoma daniconius, Ompok malabaricus, Mastacembelus armatus, Labeo calbasu, Horabragrus brachysoma, Etroplus suratensis, Danio aequipinnatus and Gonoproktopterus curmuca) collected from Kadra reservoir in Karnataka state. Results of CTM tests agrees with the species abundance as per the temperature gradient formed in the reservoir due to thermal effluent discharge. E. suratensis and H. brachysoma) appear to be adapted to high temperature (with high CTMax and CTMin values) and are in abundance at point of thermal discharge. Similarly, P. daniconius, appear to be adapted to cold (low CTM values) is in abundance in lower stretches of Kadra reservoir. Overall results indicate that discharge form nuclear power plant influences the species biodiversity in enclosed water bodies. (author)

  18. Discharge lamp technologies

    Energy Technology Data Exchange (ETDEWEB)

    Dakin, J. [GE Lighting, Cleveland, OH (United States)

    1994-12-31

    This talk is an overview of discharge lamp technology commonly employed in general lighting, with emphasis on issues pertinent to lighting for plant growth. Since the audience is primarily from the plant growth community, and this begins the light source part of the program, we will start with a brief description of the discharge lamps. Challenges of economics and of thermal management make lamp efficiency a prime concern in controlled environment agriculture, so we will emphasize science considerations relating to discharge lamp efficiency. We will then look at the spectra and ratings of some representative lighting products, and conclude with a discussion of technological advance. A general overview of discharge lighting technology can be found in the book of Waymouth (1971). A recent review of low pressure lighting discharge science is found in Dakin (1991). The pioneering paper of Reiling (1964) provides a good introduction to metal halide discharges. Particularly relevant to lighting for plant growth, a recent and thorough treatment of high pressure Na lamps is found in the book by deGroot and vanVliet (1986). Broad practical aspects of lighting application are thoroughly covered in the IES Lighting Handbook edited by Kaufman (1984).

  19. The testing of thermal-mechanical-hydrological-chemical processes using a large block

    International Nuclear Information System (INIS)

    Lin, W.; Wilder, D.G.; Blink, J.A.; Blair, S.C.; Buscheck, T.A.; Chesnut, D.A.; Glassley, W.E.; Lee, K.; Roberts, J.J.

    1994-01-01

    The radioactive decay heat from nuclear waste packages may, depending on the thermal load, create coupled thermal-mechanical-hydrological-chemical (TMHC) processes in the near-field environment of a repository. A group of tests on a large block (LBT) are planned to provide a timely opportunity to test and calibrate some of the TMHC model concepts. The LBT is advantageous for testing and verifying model concepts because the boundary conditions are controlled, and the block can be characterized before and after the experiment. A block of Topopah Spring tuff of about 3 x 3 x 4.5 m will be sawed and isolated at Fran Ridge, Nevada Test Site. Small blocks of the rock adjacent to the large block will be collected for laboratory testing of some individual thermal-mechanical, hydrological, and chemical processes. A constant load of about 4 MPa will be applied to the top and sides of the large block. The sides will be sealed with moisture and thermal barriers. The large block will be heated with one heater in each borehole and guard heaters on the sides so that a dry-out zone and a condensate zone will exist simultaneously. Temperature, moisture content, pore pressure, chemical composition, stress and displacement will be measured throughout the block during the heating and cool-down phases. The results from the experiments on small blocks and the tests on the large block will provide a better understanding of some concepts of the coupled TMHC processes

  20. Pressure-dependent synthesis of high-quality few-layer graphene by plasma-enhanced arc discharge and their thermal stability

    International Nuclear Information System (INIS)

    Kumar, Rajesh; Singh, Rajesh Kumar; Dubey, Pawan Kumar; Kumar, Pradip; Tiwari, Radhey Shyam; Oh, Il-Kwon

    2013-01-01

    In this article, a simple and cost-effective method to produce high-quality few-layer graphene (FLG) sheets (∼4 layers) have been achieved by the direct current arc discharge under argon atmosphere, using pure graphite rods as the electrodes. Ar was used as a buffer gas with pure graphite rods as anode and cathode electrodes. We explored the suitable conditions for producing FLG by changing the Ar gas pressure inside the arcing chamber. This method has several advantages over the previous methods to produce graphene for research applications. No toxic and hazardous intercalant was used for producing FLG in this process. The optimum Ar pressure was 500 Torr, for producing minimum number of FLG and this also shows the good thermal stability. The FLG product so obtained has been characterized by X-ray diffraction, scanning and electron microscopy, Raman and Fourier transform infrared spectroscopy. Thermal stabilities of FLG were determined by thermal gravimetric analysis

  1. Periodic large-amplitude thermal oscillations occurring in a buoyant plume

    International Nuclear Information System (INIS)

    Oras, J.J.; Kasza, K.E.

    1983-01-01

    Reactor events such as N-1 loop operation in conjunction with a leaky check valve in the down loop can cause flow to be convected back into the reactor outlet nozzle/piping region and to be back-flushed into the reactor outlet plenum. The preceding results in a temperature difference between pipe inflow and plenum. This temperature difference causes buoyancy forces which if large enough can cause: a pipe backflow and recirculation loop; and a thermal plume in the plenum. Both phenomena are being studied because they can produce undesirable pipe, nozzle and plenum wall thermal distributions, and hence undesirable thermal stresses. This paper discusses some features of the plume

  2. Experimental and theoretical investigation of Fe-catalysis phenomenon in hydrogen thermal desorption form hydrocarbon plasma-discharge films from T-10 tokamak

    International Nuclear Information System (INIS)

    Stankevich, V.G.; Svechnikov, N.Y.; Lebedev, A.M.; Menshikov, K.A.; Kolbasov, B.N.; Sukhanov, L.P.

    2017-01-01

    A comprehensive study of hydrocarbon films obtained in the plasma discharge of large fusion facilities will allow the minimization of parasitic capture. The investigation of the effect of Fe impurities on D 2 thermal desorption (TD) from homogeneous CD x films (x ∼ 0.5) formed in the D-plasma discharge of the T-10 tokamak were carried out. The experimental TD spectra of the films showed 2 groups of peaks at 650-850 K and 900-1000 K for 2 adsorption states. The main result of the iron catalysis effect consists in the shift of the high-temperature peak by -24 K and in the increase in the fraction of the weakly bonded adsorption states. To describe the effect of iron impurities on TD of hydrogen isotopes, a structural cluster model based on the interaction of the Fe + ion with the 1,3-C 6 H 8 molecule was proposed. The potential energy surfaces of chemical reactions with the H 2 elimination were calculated using ab initio methods of quantum chemistry. It was established that the activation barrier of hydrogen TD is reduced by about 1 eV due to the interaction of the Fe + ion with the π-subsystem of the 1,3-C 6 H 8 molecule leading to a redistribution of the double bonds along the carbon system

  3. Above and below boiling thermal loading strategies for large waste packages

    International Nuclear Information System (INIS)

    Smith, M.L.

    1994-01-01

    A simplified repository thermal model was developed with the Mathcad computer code which indicates that large waste packages may be compatible with both above and below boiling repository thermal loading strategies. Minimum spent fuel decay time of at least 20 to 30 years was shown to be important for both thermal loading strategies. Constant isothermal boundary conditions are assumed at the ground surface (296 K) and 305 meters below the water table (309.7 K) with a uniform temperature change of 1.55 10 -2 K/meter. Homogeneous tuff properties are assumed: conductivity (2.1 watt/m-k); density (2.22 gm/cm 3 ); and thermal capacitance (2.17 joule/cm 3 K). Based on these properties, the tuff thermal diffusion coefficient is 9.68 x 10 -7 m 2 /sec

  4. Hazardous gas treatment by atmospheric discharges

    International Nuclear Information System (INIS)

    Mizeraczyk, J.

    2005-01-01

    The emissions of NO x ; SO x , CO 2 and volatile organic compounds (VOCs) including fluorocarbons to the atmosphere influence heavily our environment, NO x and SO x emitted to the atmosphere are the major cause of acid rains, while CO 2 and VOCs emissions cause the greenhouse effect which leads to abnormal global heating of the atmosphere and creating in a temperature inversion layer that traps gaseous pollutants. Therefore, there is an increasing interest in controlling these emissions. A new technique, which uses the plasma processes induced by energetic electrons, emerges as one of the most effective methods of reducing concentrations of the emitted gaseous pollutants. Various plasma techniques have been tested for gaseous pollution control. The electron bean irradiation was found to be physically and economically efficient for NO x and SO x reduction in the exhaust gases from electrical and heat power plants. The capability of the non-thermal plasmas, produced in atmospheric pressure electrical discharges, for decomposition of the gaseous pollutants has been widely tested. These atmospheric pressure electrical discharges are dielectric barrier discharges, pulsed and de corona discharges (in the reactors with the point-to-plate, wire-cylinder and wire-plate geometries, in the reactors with flow stabilized corona torch and corona radical shower), gliding discharges, inductively coupled high-frequency discharges, ac surface discharges, ac discharges in the packed bed reactors, and microwave torch discharges. In this paper, after reviewing the methods and devices used for producing the non-thermal plasmas for gaseous pollutant control, some results of the laboratory experiments on the plasmas abatement of NO x ; SO x and various VOCs will be presented, followed by a discussion on the energy efficiency and by-products. Also some results obtained in the pilot-plants will be given. finally other possible applications of the presented plasma devices for controlling

  5. Sandia Laboratories in-house activities in support of solar thermal large power applications

    Science.gov (United States)

    Mar, R. W.

    1980-01-01

    The development of thermal energy storage subsystems for solar thermal large power applications is described. The emphasis is on characterizing the behavior of molten nitrate salts with regard to thermal decomposition, environmental interactions, and corrosion. Electrochemical techniques to determine the ionic species in the melt and for use in real time studies of corrosion are also briefly discussed.

  6. Environmental effects of thermal and radioactive discharges from nuclear power plants in the boreal brackish-water conditions of the northern Baltic Sea

    International Nuclear Information System (INIS)

    Ilus, E.

    2009-08-01

    During recent decades, thermal and radioactive discharges from nuclear power plants into the aquatic environment have become the subject of lively debate as an ecological concern. Recently, an increasing demand for facts has appeared in context with the Environmental Impact Assessment procedures that are being in progress for planned new nuclear power units in Finland. The target of this thesis was to summarize the large quantity of results obtained in extensive monitoring programmes and studies carried out in recipient sea areas off the Finnish nuclear power plants at Loviisa and Olkiluoto during more than four decades. Especially in the conditions specific for the northern Baltic Sea, where biota is poor and adapted to relatively low temperatures and to seasonal variation with a cold ice winter and a temperate summer, an increase in temperature may cause increased environmental stress to the organisms. Furthermore, owing to the brackish-water character of the Baltic Sea, many organisms live there near the limit of their physiological tolerance. On the other hand, the low salinity increases the uptake of certain radionuclides by many organisms in comparison with oceanic conditions. The sea areas surrounding the Finnish nuclear power plants differ from each other in many respects (efficiency of water exchange, levels of nutrients and other water quality parameters, water salinity and consequent differences in species composition, abundance and vitality of biota). In addition, there are differences in the discharge quantities and discharge design of the power plants. In this thesis the environmental effects of the two power plants on the water recipients are compared and their relative significance is assessed

  7. Performance of Cobalt-Based Fischer-Tropsch Synthesis Catalysts Using Dielectric-Barrier Discharge Plasma as an Alternative to Thermal Calcination

    International Nuclear Information System (INIS)

    Bai Suli; Huang Chengdu; Lv Jing; Li Zhenhua

    2012-01-01

    Co-based catalysts were prepared by using dielectric-barrier discharge (DBD) plasma as an alternative method to conventional thermal calcination. The characterization results of N 2 -physisorption, temperature programmed reduction (TPR), transmission electron microscope (TEM), and X-ray diffraction (XRD) indicated that the catalysts prepared by DBD plasma had a higher specific surface area, lower reduction temperature, smaller particle size and higher cobalt dispersion as compared to calcined catalysts. The DBD plasma method can prevent the sintering and aggregation of active particles on the support due to the decreased treatment time (0.5 h) at lower temperature compared to the longer thermal calcination at higher temperature (at 500° C for 5 h). As a result, the catalytic performance of the Fischer-Tropsch synthesis on DBD plasma treated Co/SiO 2 catalyst showed an enhanced activity, C 5+ selectivity and catalytic stability as compared to the conventional thermal calcined Co/SiO 2 catalyst.

  8. The effects of season and sand mining activities on thermal regime and water quality in a large shallow tropical lake.

    Science.gov (United States)

    Sharip, Zati; Zaki, Ahmad Taqiyuddin Ahmad

    2014-08-01

    Thermal structure and water quality in a large and shallow lake in Malaysia were studied between January 2012 and June 2013 in order to understand variations in relation to water level fluctuations and in-stream mining activities. Environmental variables, namely temperature, turbidity, dissolved oxygen, pH, electrical conductivity, chlorophyll-A and transparency, were measured using a multi-parameter probe and a Secchi disk. Measurements of environmental variables were performed at 0.1 m intervals from the surface to the bottom of the lake during the dry and wet seasons. High water level and strong solar radiation increased temperature stratification. River discharges during the wet season, and unsustainable sand mining activities led to an increased turbidity exceeding 100 NTU, and reduced transparency, which changed the temperature variation and subsequently altered the water quality pattern.

  9. Combined use of thermal methods and seepage meters to efficiently locate, quantify, and monitor focused groundwater discharge to a sand-bed stream

    Science.gov (United States)

    Rosenberry, Donald O.; Briggs, Martin A.; Delin, Geoffrey N.; Hare, Danielle K.

    2016-01-01

    Quantifying flow of groundwater through streambeds often is difficult due to the complexity of aquifer-scale heterogeneity combined with local-scale hyporheic exchange. We used fiber-optic distributed temperature sensing (FO-DTS), seepage meters, and vertical temperature profiling to locate, quantify, and monitor areas of focused groundwater discharge in a geomorphically simple sand-bed stream. This combined approach allowed us to rapidly focus efforts at locations where prodigious amounts of groundwater discharged to the Quashnet River on Cape Cod, Massachusetts, northeastern USA. FO-DTS detected numerous anomalously cold reaches one to several m long that persisted over two summers. Seepage meters positioned upstream, within, and downstream of 7 anomalously cold reaches indicated that rapid groundwater discharge occurred precisely where the bed was cold; median upward seepage was nearly 5 times faster than seepage measured in streambed areas not identified as cold. Vertical temperature profilers deployed next to 8 seepage meters provided diurnal-signal-based seepage estimates that compared remarkably well with seepage-meter values. Regression slope and R2 values both were near 1 for seepage ranging from 0.05 to 3.0 m d−1. Temperature-based seepage model accuracy was improved with thermal diffusivity determined locally from diurnal signals. Similar calculations provided values for streambed sediment scour and deposition at subdaily resolution. Seepage was strongly heterogeneous even along a sand-bed river that flows over a relatively uniform sand and fine-gravel aquifer. FO-DTS was an efficient method for detecting areas of rapid groundwater discharge, even in a strongly gaining river, that can then be quantified over time with inexpensive streambed thermal methods.

  10. Discharge physics and chemistry of a novel atmospheric pressure plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.; Henins, I.; Hermann, J.W.; Selwyn, G.S.; Jeong, J.Y.; Hickis, R.

    1999-07-01

    The atmospheric pressure plasma jet (APPJ) is a unique plasma source operating at atmospheric pressure. The APPJ operates with RF power and produces a stable non-thermal discharge in capacitively-coupled configuration. The discharge is spatially and temporally homogeneous and provides a unique gas phase chemistry that is well suited for various applications including etching, film deposition, surface treatment and decontamination of chemical and biological warfare (CBW) agents. A theoretical model shows electron densities of 0.2--2 x 10{sup 11} cm{sup {minus}3} for a helium discharge at a power level of 3--30 W cm{sup {minus}3}. The APPJ also produces a large flux, equivalent of up to 10,000 monolayer s{sup {minus}1}, of chemically-active, atomic and metastable molecular species which can impinge surfaces several cm downstream of the confined source. In addition, the efforts are in progress to measure the electron density using microwave diagnostics and to benchmark the gas phase chemical model by using LIF and titration.

  11. Spring-like motion caused large anisotropic thermal expansion in nonporous M(eim)2 (M = Zn, Cd).

    Science.gov (United States)

    Liu, Zhanning; Liu, Chenxi; Li, Qiang; Chen, Jun; Xing, Xianran

    2017-09-20

    Two nonporous coordination polymers were found to possess large anisotropic thermal expansion, which was derived from the flexible structures. A "spring-like" thermal motion was proposed to illustrate the mechanism. Compound Cd(eim) 2 (eim = 2-ethylimidazole) possesses large linear and reversible thermal expansion properties and the emission intensity shows a linear decrease with temperature, making it a candidate for thermo-responsive materials.

  12. Triggering and guiding high-voltage large-scale leader discharges with sub-joule ultrashort laser pulses

    International Nuclear Information System (INIS)

    Pepin, H.; Comtois, D.; Vidal, F.; Chien, C.Y.; Desparois, A.; Johnston, T.W.; Kieffer, J.C.; La Fontaine, B.; Martin, F.; Rizk, F.A.M.; Potvin, C.; Couture, P.; Mercure, H.P.; Bondiou-Clergerie, A.; Lalande, P.; Gallimberti, I.

    2001-01-01

    The triggering and guiding of leader discharges using a plasma channel created by a sub-joule ultrashort laser pulse have been studied in a megavolt large-scale electrode configuration (3-7 m rod-plane air gap). By focusing the laser close to the positive rod electrode it has been possible, with a 400 mJ pulse, to trigger and guide leaders over distances of 3 m, to lower the leader inception voltage by 50%, and to increase the leader velocity by a factor of 10. The dynamics of the breakdown discharges with and without the laser pulse have been analyzed by means of a streak camera and of electric field and current probes. Numerical simulations have successfully reproduced many of the experimental results obtained with and without the presence of the laser plasma channel

  13. Field studies of the thermal plume from the D. C. Cook submerged discharge with comparisons to hydraulic-model results

    International Nuclear Information System (INIS)

    Frigo, A.A.; Paddock, R.A.; McCown, D.L.

    1975-06-01

    The Donald C. Cook Nuclear Plant at Bridgman, Michigan, uses submerged-diffuser discharges as a means of disposing waste heat into Lake Michigan. Preliminary results of temperature surveys of the thermal plume at the D. C. Cook Plant are presented. Indications are that the spatial extent of the plume at the surface is much smaller than previous results for surface shoreline discharges, particularly in the near and intermediate portions of the plume. Comparisons of limited prototype data with hydraulic (tank)-model predictions indicate that the model predictions for centerline temperature decay at the surface are too high for the initial 200 m from the discharge, but are generally correct beyond this point to the limits of the model. In addition, the hydraulic-model results underestimate the areal extent of the near and intermediate portions of the plume at the surface. Because this is the first report of a new field program, several inadequacies in the field-measurement techniques are noted and discussed. New techniques that have been developed to remedy these deficiencies, and which will be implemented for future field work, are also described. (auth)

  14. Discharge behaviors during plasma electrolytic oxidation on aluminum alloy

    International Nuclear Information System (INIS)

    Liu, Run; Wu, Jie; Xue, Wenbin; Qu, Yao; Yang, Chaolin; Wang, Bin; Wu, Xianying

    2014-01-01

    A plasma electrolytic oxidation (PEO) process was performed on the 2024 aluminum alloy in silicate electrolyte to fabricate ceramic coatings under a constant voltage. Optical emission spectroscopy (OES) was employed to evaluate the characteristics of plasma discharge during PEO process. The plasma electron temperature and density were obtained by analyzing the spectral lines of OES, and the atomic ionization degree in discharge zone was calculated in terms of Saha thermal ionization equation. The illumination intensity of plasma discharge and the temperature in the interior of alloy were measured. Combining the surface morphology and cross-sectional microstructure with the optical emission spectra and illumination at different discharge stage, a discharge model in the growth of PEO ceramic coatings was proposed. It is found that there are two discharge modes of type A with small spark size and type B with large spark size, and the latter only appears in the intermediate stage of PEO process. The illumination intensity has a maximum value in the initial stage of oxidation with many sparks of discharge type A. The electron temperature in plasma discharge zone is about 3000 K–7000 K and atomic ionization degree of Al is about 2.0 × 10 −5 –7.2 × 10 −3 , which depend on discharge stage. The discharge type B plays a key role on the electron temperature and atomic ionization degree. The electron density keeps stable in the range of about 8.5 × 10 21  m −3 –2.6 × 10 22  m −3 . - Highlights: • The characteristics of PEO plasma discharge was evaluated by OES. • Electron temperature, concentration, atomic ionization degree were calculated. • Discharge model for the growth of PEO coatings was proposed. • Temperature in the interior of alloy during PEO process was measured

  15. Apparatus for atmospheric pressure pin-to-hole spark discharge and uses thereof

    Science.gov (United States)

    Dobrynin, Danil V.; Fridman, Alexander; Cho, Young I.; Fridman, Gregory; Friedman, Gennady

    2016-12-06

    Disclosed herein are atmospheric pressure pin-to-hole pulsed spark discharge devices and methods for creating plasma. The devices include a conduit for fluidically communicating a gas, a plasma, or both, therethrough, portion of the conduit capable of being connected to a gas supply, and a second portion of the conduit capable of emitting a plasma; a positive electrode comprising a sharp tip; and a ground plate electrode. Disclosed are methods for treating a skin ulcer using non-thermal plasma include flowing a gas through a cold spark discharge zone simultaneously with the creation of a pulsed spark discharge to give rise to a non-thermal plasma emitted from a conduit, the non-thermal plasma comprising NO; and contacting a skin ulcer with said non-thermal plasma for sufficient time and intensity to give rise to treatment of the skin ulcer.

  16. Vanadium Dioxide as a Natural Disordered Metamaterial: Perfect Thermal Emission and Large Broadband Negative Differential Thermal Emittance

    Directory of Open Access Journals (Sweden)

    Mikhail A. Kats

    2013-10-01

    Full Text Available We experimentally demonstrate that a thin (approximately 150-nm film of vanadium dioxide (VO_{2} deposited on sapphire has an anomalous thermal emittance profile when heated, which arises because of the optical interaction between the film and the substrate when the VO_{2} is at an intermediate state of its insulator-metal transition (IMT. Within the IMT region, the VO_{2} film comprises nanoscale islands of the metal and dielectric phases and can thus be viewed as a natural, disordered metamaterial. This structure displays “perfect” blackbodylike thermal emissivity over a narrow wavelength range (approximately 40  cm^{-1}, surpassing the emissivity of our black-soot reference. We observe large broadband negative differential thermal emittance over a >10 °C range: Upon heating, the VO_{2}-sapphire structure emits less thermal radiation and appears colder on an infrared camera. Our experimental approach allows for a direct measurement and extraction of wavelength- and temperature-dependent thermal emittance. We anticipate that emissivity engineering with thin-film geometries comprising VO_{2} and other thermochromic materials will find applications in infrared camouflage, thermal regulation, and infrared tagging and labeling.

  17. Numerical Modeling of Water Thermal Plumes Emitted by Thermal Power Plants

    Directory of Open Access Journals (Sweden)

    Azucena Durán-Colmenares

    2016-10-01

    Full Text Available This work focuses on the study of thermal dispersion of plumes emitted by power plants into the sea. Wastewater discharge from power stations causes impacts that require investigation or monitoring. A study to characterize the physical effects of thermal plumes into the sea is carried out here by numerical modeling and field measurements. The case study is the thermal discharges of the Presidente Adolfo López Mateos Power Plant, located in Veracruz, on the coast of the Gulf of Mexico. This plant is managed by the Federal Electricity Commission of Mexico. The physical effects of such plumes are related to the increase of seawater temperature caused by the hot water discharge of the plant. We focus on the implementation, calibration, and validation of the Delft3D-FLOW model, which solves the shallow-water equations. The numerical simulations consider a critical scenario where meteorological and oceanographic parameters are taken into account to reproduce the proper physical conditions of the environment. The results show a local physical effect of the thermal plumes within the study zone, given the predominant strong winds conditions of the scenario under study.

  18. Thermo-structural modelling of a plasma discharge tube for electric propulsion

    International Nuclear Information System (INIS)

    Faoite, D. de; Browne, D.J.; Del Valle Gamboa, J.I.; Stanton, K.T.

    2016-01-01

    Highlights: • Thermo-structural analyses were performed for an electric propulsion space thruster. • Thermal stresses arise primarily from mismatches in thermal expansion coefficients. • Aluminium nitride is a suitable material for a plasma containment tube. • A design is presented allowing a thruster to operate at a power of at least 250 kW. - Abstract: Potential thermal management strategies for the plasma generation section of a VASIMR"® high-power electric propulsion space thruster are assessed. The plasma is generated in a discharge tube using helicon waves. The plasma generation process causes a significant thermal load on the plasma discharge tube and on neighbouring components, caused by cross-field particle diffusion and UV radiation. Four potential cooling system design strategies are assessed to deal with this thermal load. Four polycrystalline ceramics are evaluated for use as the plasma discharge tube material: alumina, aluminium nitride, beryllia, and silicon nitride. A finite element analysis (FEA) method was used to model the steady-state temperature and stress fields resulting from the plasma heat flux. Of the four materials assessed, aluminium nitride would result in the lowest plasma discharge tube temperatures and stresses. It was found that a design consisting of a monolithic ceramic plasma containment tube fabricated from aluminium nitride would be capable of operating up to a power level of at least 250 kW.

  19. Angra-1 NPP thermal influence on liquid effluent discharge zone

    International Nuclear Information System (INIS)

    Costa, Daniel de Araujo

    1996-01-01

    The Angra I Nuclear Power Plant makes use of sea-water to condense the steam generated in its secondary circuit. This water, collected from Itaorna bay, is then chlorinated and discharged, with higher temperature, in the Piraquara de Fora bay. Aiming the study of the marine ecosystem, submitted to the effects of the Nuclear Power Plant discharge water, the temperature, residual chlorine, flora and fauna are periodically monitored. Being sensitive to temperature variations and to chemical products, macroscopic algae are also bio-accumulators and primary producers, because of this, they are considered the main link in the food chain and therefore important bio-indicator. This paper shows the variation of species from the brown algae near the discharge of Angra I Nuclear Power Plant. (author)

  20. Diagnosis of the local thermal equilibrium by optical emission spectroscopy in the evolution of electric discharge; Diagnostico del equilibrio termico local por espectroscopia optica de emision en la evolucion de una descarga electrica

    Energy Technology Data Exchange (ETDEWEB)

    Valdivia B, R.; Pacheco S, J.; Pacheco P, M.; Ramos F, F.; Cruz A, A. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Velazquez P, S. [Instituto Tecnologico de Toluca, Av. Instituto Tecnologico s/n, Ex-Rancho la Virgen, Metepec 52140, Estado de Mexico (Mexico)

    2008-07-01

    In this work applies the technique of optical emission spectroscopy to diagnose the temperature of the species generated in plasma in the transition to glow discharge arc. Whit this diagnosis is possible to determine the local thermal equilibrium conditions of the discharge. (Author)

  1. Power Generation from a Radiative Thermal Source Using a Large-Area Infrared Rectenna

    Science.gov (United States)

    Shank, Joshua; Kadlec, Emil A.; Jarecki, Robert L.; Starbuck, Andrew; Howell, Stephen; Peters, David W.; Davids, Paul S.

    2018-05-01

    Electrical power generation from a moderate-temperature thermal source by means of direct conversion of infrared radiation is important and highly desirable for energy harvesting from waste heat and micropower applications. Here, we demonstrate direct rectified power generation from an unbiased large-area nanoantenna-coupled tunnel diode rectifier called a rectenna. Using a vacuum radiometric measurement technique with irradiation from a temperature-stabilized thermal source, a generated power density of 8 nW /cm2 is observed at a source temperature of 450 °C for the unbiased rectenna across an optimized load resistance. The optimized load resistance for the peak power generation for each temperature coincides with the tunnel diode resistance at zero bias and corresponds to the impedance matching condition for a rectifying antenna. Current-voltage measurements of a thermally illuminated large-area rectenna show current zero crossing shifts into the second quadrant indicating rectification. Photon-assisted tunneling in the unbiased rectenna is modeled as the mechanism for the large short-circuit photocurrents observed where the photon energy serves as an effective bias across the tunnel junction. The measured current and voltage across the load resistor as a function of the thermal source temperature represents direct current electrical power generation.

  2. A novel synthesis method for large area metallic amorphous/nanocrystal films by the glow-discharge plasma technique

    International Nuclear Information System (INIS)

    Xu Jiang; Xu Zhong; Tao Jie; Liu Zili; Chen Zheyuan; Zhu Wenhui

    2007-01-01

    Two large-area metallic amorphous/nanocrystal films were prepared on AZ31 magnesium alloy and pure iron substrates by the double glow-discharge plasma technique. The formation mechanism of the novel amorphous films did not follow the established empirical rules for large glass-forming ability. The amorphous films were composed of binary alloys with a difference in the atomic diameter of alloying constituents of less than 12%, and an amorphous film of pure iron was successfully obtained

  3. Thermal test of the insulation structure for LH 2 tank by using the large experimental apparatus

    Science.gov (United States)

    Kamiya, S.; Onishi, K.; Konshima, N.; Nishigaki, K.

    Conceptual designs of large mass LH 2 (liquid hydrogen) storage systems, whose capacity is 50,000 m3, have been studied in the Japanese hydrogen project, World Energy Network (WE-NET) [K. Fukuda, in: WE-NET Hydrogen Energy Symposium, 1999, P1-P41]. This study has concluded that their thermal insulation structures for the huge LH 2 tanks should be developed. Their actual insulation structures comprise not only the insulation material but also reinforced members and joints. To evaluate their thermal performance correctly, a large test specimen including reinforced members and joints will be necessary. After verifying the thermal performance of a developed large experimental apparatus [S. Kamiya, Cryogenics 40 (1) (2000) 35] for measuring the thermal conductance of various insulation structures, we tested two specimens, a vacuum multilayer insulation (MLI) with a glass fiber reinforced plastic (GFRP) support and a vacuum solid insulation (microtherm ®) with joints. The thermal background test for verifying the thermal design of the experimental apparatus showed that the background heat leak is 0.1 W, small enough to satisfy apparatus performance requirement. The thermal conductance measurements of specimens also showed that thermal heat fluxes of MLI with a GFRP support and microtherm ® are 8 and 5.4 W/m2, respectively.

  4. Preliminary fluid channel design and thermal-hydraulic analysis of glow discharge cleaning permanent electrode

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Lijun, E-mail: cailj@swip.ac.cn [Southwestern Institute of Physics, Chengdu (China); Lin, Tao; Wang, Yingqiao; Wang, Mingxu [Southwestern Institute of Physics, Chengdu (China); Maruyama, So; Yang, Yu; Kiss, Gabor [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2016-11-01

    Highlights: • The plasma facing closure cap has to survive after 30,000 thermal heat load cycles. • 0.35 MW/m2 radiation heat load plus nuclear heat load are very challenging for stainless steel. • Multilayer structure has been designed by using advanced welding and drilling technology to solve the neutron heating problem. • Accurate volumetric load application in analysis model by CFX has been mastered. - Abstract: Glow discharge cleaning (GDC) shall be used on ITER device to reduce and control impurity and hydrogenic fuel out-gassing from in-vessel plasma facing components. After first plasma, permanent electrode (PE) will be used to replace Temporary Electrode (TE) for subsequent operation. Two fundamental scenarios i.e., GDC and Plasma Operation State (POS) should be considered for electrode design, which requires the heat load caused by plasma radiation and neutron heating must be taken away by cooling water flowing inside the electrode. In this paper, multilayer cooling channels inside PE are preliminarily designed, and snakelike route in each layer is adopted to improve the heat exchange. Detailed thermal-hydraulic analyses have been done to validate the design feasibility or rationality. The analysis results show that during GDC the cooling water inlet and outlet temperature difference is far less than the allowable temperature rise under water flow rate 0.15 kg/s compromised by many factors. For POS, the temperature rise and pressure drop are within the design goals, but high thermal stress occurs on the front surface of closure cap of electrode. After several iterations of optimization of the closure cap, the equivalent strain range after 30,000 loading cycles for POS is well below 0.3% design goals.

  5. Optical and thermal energy discharge from tritiated solid hydrogen

    International Nuclear Information System (INIS)

    Magnotta, F.; Mapoles, E.R.; Collins, G.W.; Souers, P.C.

    1991-01-01

    The authors are investigating mechanisms of energy storage and release in tritiated solid hydrogens, by a variety of techniques including ESR, NMR and thermal and optical emission. The nuclear decay of a triton in solid hydrogen initiates the conversion of nuclear energy into stored chemical energy by producing unpaired hydrogen atoms which are trapped within the molecular lattice. The ability to store large quantities of atoms in this manner has been demonstrated and can serve as a basis for new forms of high energy density materials. This paper presents preliminary results of a study of the optical emission from solid hydrogen containing tritium over the visible and near infrared (NIR) spectral regions. Specifically, they have studied optical emission from DT and T 2 using CCD, silicon diode and germanium diode arrays. 8 refs., 6 figs

  6. Ballooning stability of JET discharges

    International Nuclear Information System (INIS)

    Huysmans, G.T.A.; Goedbloed, J.P.; Galvao, R.M.O.; Lazzaro, E.; Smeulders, P.

    1989-01-01

    Conditions under which ballooning modes are expected to be excited have recently been obtained in two different types of discharges in JET. In the first type, extremely large pressure gradients have been produced in the plasma core through pellet injections in the current rise phase followed by strong additional heating. In the second type, the total pressure of the discharge is approaching the Troyon limit. The stability of these discharges with respect to the ideal MHD ballooning modes has been studied with the stability code HBT. The equilibria are reconstructed with the IDENTC code using the external magnetic measurements and the experimental pressure profile. The results show that the evaluated high beta discharge is unstable in the central region of the plasma. This instability is related to the low shear and not to a large pressure gradient, as expected at the Troyon limit. In the pellet discharges the regions with the large pressure gradients are unstable to ballooning modes at the time of the beta decay, which ends the period of enhanced performance. The maximum pressure gradient in these discharges is limited by the boundary of the first region of stability. The observed phenomena at the beta decay are similar to those observed at the beta limit in DIII-D and TFTR. (author)

  7. Thermal analysis of the large close packed amplifiers in the National Ignition Facility (NIF)

    International Nuclear Information System (INIS)

    Brown, D.L.; Mannell, G.T.

    1995-05-01

    Flashlamp pumping of the large aperture multi-segment NIF amplifiers will result in large amounts of energy being deposited as heat in the amplifier components. The magnitude of the heating and the nonuniform distribution result in a delay time between shots due to wavefront distortion and steering error. A NEF requirement is that the thermal wavefront recovery must occur in less than six hours. The principal cause of long-term wavefront distortion is the thermal gradient produced in the slab as heat diffuses from the edge cladding into the pumped volume. Thermal equilibrium is established through conduction, convection, and exchange of thermal radiation. Radiative exchange between glass components, such as flashlamps, blast shields, and laser slabs is especially effective because of the large surface areas of these components and the high emissivity of the glass. Free convection within the amplifier enclosure is also important but is on the order of a 10 to 20% effect compared to radiation for the major surfaces. To evaluate the NIF design, the amplifier was modeled to calculate the thermal response of a single laser element. The amplifier is cooled by flowing room-temperature air or nitrogen through the flashlamp cassettes. Active cooling of the flashlamps and blast shields serves two purposes; the energy deposited in these components can be removed before it is transferred to the amplifier optical components, and the cooled blast shield provides a large area heat sink for removal of the residual heat from the laser slabs. Approximately 50 to 60% of the flashlamp energy is deposited in the flashlamps and blast shields. Thus, cooling the flashlamp cassette is a very effective method for removing a substantial fraction of the energy without disturbing the optical elements of the system. Preliminary thermal analysis indicates that active cooling with flow rates of 10 CFM per flashlamp is sufficient to meet the six hour thermal equilibrium requirement

  8. Plasma diagnostics discharge parameters and chemistry

    CERN Document Server

    Auciello, Orlando

    1989-01-01

    Plasma Diagnostics, Volume 1: Discharge Parameters and Chemistry covers seven chapters on the important diagnostic techniques for plasmas and details their use in particular applications. The book discusses optical diagnostic techniques for low pressure plasmas and plasma processing; plasma diagnostics for electrical discharge light sources; as well as Langmuir probes. The text also describes the mass spectroscopy of plasmas, microwave diagnostics, paramagnetic resonance diagnostics, and diagnostics in thermal plasma processing. Electrical engineers, nuclear engineers, microwave engineers, che

  9. Analytical model to describe the thermal behavior of a heat discharge system in roofs; Modelo analitico que describe el comportamiento termico de un sistema de descarga de calor en techos

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Gomez, V.H.; Contreras-Espinosa, J.J.; Gonzalez-Ortiz, G.; Morillon-Galvez, D.; Fernandez-Zayas, J.L. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: vichugo@servidor.unam.mx; jjuancon2000@yahoo.com.mx; gilberto_gonzalez25@hotmail.com; damg@pumas.iingen.unam.mx; JFernandezZ@iingen.unam.mx

    2012-01-15

    The present study proposes an analytical model which describes the thermal behavior of a heat discharge system in roof, when the surfaces that constitute it are not translucent. Such a model derives from a thermal balance carried out to a heat discharge system in roofs. To validate it, an experimental prototype that allows simulating the thermal behavior of a heat discharge system in wall and roof was used, and the results were compared to those obtained with the proposed analytical model. It was found that the thermal behavior of the analytical model is similar to the thermal behavior of the experimental prototype; a worthless variation was detected among their respective outcome (The difference of temperatures can be caused by the heat transfer coefficient, of which no studies defining its behavior accurately have been found). Therefore, it can be considered that the proposed analytical model can be employed to simulate the thermal behavior of a heat discharge system in roofs when the surfaces that constitute it are opaque. [Spanish] En el presente estudio se propone un modelo analitico que describe el comportamiento termico de un sistema de descarga de calor en techo, cuando las superficies que lo componen no son translucidos. Dicho modelo surge a partir de un balance termico realizado a un sistema de descarga de calor en techos. Para validarlo, se realizaron dos corridas experimentales en un prototipo que permite simular el comportamiento termico de un sistema de descarga de calor en techo y se compararon los resultados medidos con los calculados por el modelo analitico propuesto. Se encontro que, el comportamiento termico del modelo analitico es similar al comportamiento termico del prototipo experimental, se detecto una variacion despreciable entre los valores arrojados por ambos modelos (la diferencia de temperaturas puede estar ocasionada por la obtencion del coeficiente convectivo de transferencia de calor, del cual no se han encontrado estudios que

  10. Pressure supression pool thermal mixing

    International Nuclear Information System (INIS)

    Cook, D.H.

    1984-10-01

    A model is developed and verified to describe the thermal mixing that occurs in the pressure suppression pool (PSP) of a commercial BWR. The model is designed specifically for a Mark-I containment and is intended for use in severe accident sequence analyses. The model developed in this work produces space and time dependent temperature results throughout the PSP and is useful for evaluating the bulk PSP thermal mixing, the condensation effectiveness of the PSP, and the long-term containment integrity. The model is designed to accommodate single or multiple discharging T-quenchers, a PSP circumferential circulation induced by the residual heat removal system discharge, and the thermal stratification of the pool that occurs immediately after the relief valves close. The PSP thermal mixing is verified by comparing the model-predicted temperatures to experimental temperatures that were measured in an operating BWR suppression pool. The model is then used to investigate several PSP thermal mixing problems that include the time to saturate at full relief valve flow, the temperature response to a typical stuck open relief valve scenario, and the effect of operator rotation of the relief valve discharge point

  11. Pressure suppression pool thermal mixing

    International Nuclear Information System (INIS)

    Cook, D.H.

    1984-01-01

    A model is developed and verified to describe the thermal mixing that occurs in the pressure suppression pool (PSP) of a commercial BWR. The model is designed specifically for a Mark-I containment and is intended for use in severe accident sequence analyses. The model produces space and time dependent temperature results throughout the PSP and is useful for evaluating the bulk PSP thermal mixing, the condensation effectiveness of the PSP, and the long-term containment integrity. The model is designed to accommodate single or multiple discharging T-quenchers, a PSP circumferential circulation induced by the residual heat removal system discharge, and the thermal stratification of the pool that occurs immediately after the relief valves close. The PSP thermal mixing model is verified by comparing the model predicted temperatures to experimental temperatures that were measured in an operating BWR suppression pool. The model is then used to investigate several PSP thermal mixing problems that include the time to saturate at full relief valve flow, the temperature response to a typical stuck open relief valve scenario, and the effect of operator rotation of the relief valve discharge point

  12. The discharge of nitrate-contaminated groundwater from developed shoreline to marsh-fringed estuary

    Science.gov (United States)

    Portnoy, J.W.; Nowicki, B.L.; Roman, C.T.; Urish, D.W.

    1998-01-01

    As residential development, on-site wastewater disposal, and groundwater contamination increase in the coastal zone, assessment of nutrient removal by soil and sedimentary processes becomes increasingly important. Nitrogen removal efficiency depends largely on the specific flow paths taken by groundwater as it discharges into nitrogen-limited estuarine waters. Shoreline salinity surveys, hydraulic studies, and thermal infrared imagery indicated that groundwater discharge into the Nauset Marsh estuary (Eastham, Massachusetts) occurred in high-velocity seeps immediately seaward of the upland-fringing salt marsh. Discharge was highly variable spatially and occurred through permeable, sandy sediments during low tide. Seepage chamber monitoring showed that dissolved inorganic nitrogen (principally nitrate) traversed nearly conservatively from the aquifer through shallow estuarine sediments to coastal waters at flux rates of 1–3 mmol m−2 h−1. A significant relationship between pore water NO3-N concentrations and NO3-N flux rates may provide a rapid method of estimating nitrogen loading from groundwater to the water column.

  13. Numerical simulation of nanosecond-pulse electrical discharges

    Science.gov (United States)

    Poggie, J.; Adamovich, I.; Bisek, N.; Nishihara, M.

    2013-02-01

    Recent experiments with a nanosecond-pulse, dielectric barrier discharge at the stagnation point of a Mach 5 cylinder flow have demonstrated the formation of weak shock waves near the electrode edge, which propagate upstream and perturb the bow shock. This is a promising means of flow control, and understanding the detailed physics of the conversion of electrical energy into gas motion will aid in the design of efficient actuators based on the concept. In this work, a simplified configuration with planar symmetry was chosen as a vehicle to develop a physics-based model of nanosecond-pulse discharges, including realistic air kinetics, electron energy transport, and compressible bulk gas flow. A reduced plasma kinetic model (23 species and 50 processes) was developed to capture the dominant species and reactions for energy storage and thermalization in the discharge. The kinetic model included electronically and vibrationally excited species, and several species of ions and ground state neutrals. The governing equations included the Poisson equation for the electric potential, diffusion equations for each neutral species, conservation equations for each charged species, and mass-averaged conservation equations for the bulk gas flow. The results of calculations with this model highlighted the path of energy transfer in the discharge. At breakdown, the input electrical energy was transformed over a time scale on the order of 1 ns into chemical energy of ions, dissociation products, and vibrationally and electronically excited particles. About 30% of this energy was subsequently thermalized over a time scale of 10 µs. Since the thermalization time scale was faster than the acoustic time scale, the heat release led to the formation of weak shock waves originating near the sheath edge, consistent with experimental observations. The computed translational temperature rise (40 K) and nitrogen vibrational temperature rise (370 K) were of the same order of magnitude as

  14. Transient, two-dimensional, discrete-element, far-field model for thermal impact analysis of power plant discharges in coastal and offshore regions. Part I. General description of the mathematical model and the results of an application

    International Nuclear Information System (INIS)

    Eraslan, A.H.

    1975-02-01

    A far-field mathematical model is presented for numerical simulation of short-time (within tidal cycle) transient, two-dimensional temperature distributions in large coastal and offshore regions resulting from the condenser cooling water discharges of power plants. The Eulerian FLIDE (fluid-in-discrete-element) formulation employs the integral forms of the conservation principles for mass and thermal energy in variable-sized discrete elements that span the specific flow region. The contributions of vertical variations of the velocity components and temperature are rigorously incorporated in the development of depth-averaged, two-dimensional energy transport fluxes by spatially integrating the conservation equations over the enclosure surfaces of the discrete elements. The general mathematical formulation considers completely arbitrary, transient oceanic flow conditions, which include periodic tidal, geostrophic, and wind-induced currents, as locally specified inputs to the model. The thermal impact of a hypothetical, multiunit generating station in a coastal region is analyzed where the oceanic flow conditions are assumed to be strictly periodic tidal currents within any appreciable net drift of sufficient duration to remove the heated effluent. The numerical simulation indicates that the periodic flow conditions cause considerable variations in the temperature distributions during the day and the tidal cycles, which result in severe recirculation and re-entrainment of the heated water between the intakes and the discharges of the different units. This leads to a gradual, long-term increase of the temperatures in the immediate vicinity of the discharge structures and also in the far-field zone. (U.S.)

  15. Thermal activation of dislocations in large scale obstacle bypass

    Science.gov (United States)

    Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; Martinez, Enrique

    2017-08-01

    Dislocation dynamics simulations have been used extensively to predict hardening caused by dislocation-obstacle interactions, including irradiation defect hardening in the athermal case. Incorporating the role of thermal energy on these interactions is possible with a framework provided by harmonic transition state theory (HTST) enabling direct access to thermally activated reaction rates using the Arrhenius equation, including rates of dislocation-obstacle bypass processes. Moving beyond unit dislocation-defect reactions to a representative environment containing a large number of defects requires coarse-graining the activation energy barriers of a population of obstacles into an effective energy barrier that accurately represents the large scale collective process. The work presented here investigates the relationship between unit dislocation-defect bypass processes and the distribution of activation energy barriers calculated for ensemble bypass processes. A significant difference between these cases is observed, which is attributed to the inherent cooperative nature of dislocation bypass processes. In addition to the dislocation-defect interaction, the morphology of the dislocation segments pinned to the defects play an important role on the activation energies for bypass. A phenomenological model for activation energy stress dependence is shown to describe well the effect of a distribution of activation energies, and a probabilistic activation energy model incorporating the stress distribution in a material is presented.

  16. Thermal results of the Japanese LCT coil's domestic test

    International Nuclear Information System (INIS)

    Tada, Eisuke; Hiyama, Tadao; Kato, Takashi; Takahashi, Osamu; Shimamoto, Susumu

    1984-01-01

    This paper describes thermal results obtained in the domestic test of the Japanese LCT coil which was constructed at the Japan Atomic Energy Research Institute (JAERI) in order to develop large superconducting coils for fusion in international collaboration proposed by the IEA. The domestic test was carried out from May 13 to June 17 in 1982 by using the test facility named as SETF (Superconducting Engineering Test Facility) which was composed of a 350-l/h helium cryogenic system, a vacuum system, a 30 KA-DC power supply and protection system, and a PDP-11/70 computer system. The cool-down characteristics, heat load, fast discharge characteristics, stability, and warm-up characteristics of the LCT coil were successfully measured in the test. The details of thermal test results acquired in the cool-down, heat load measurement, fast discharge, and warm-up, and the comparison between measurements and calculations are described in this paper. (author)

  17. 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

  18. Body temperatures of fish feeding in the Point Beach thermal discharge

    International Nuclear Information System (INIS)

    Spigarelli, S.A.; Thommes, M.M.

    1974-01-01

    Between April and November, 1973, measurements of internal body temperature were made on 1310 fish caught by fishermen at the Point Beach Nuclear Plant. Records were also made of fish weight, length, and sex and intake and discharge temperatures. A table is presented to show mean monthly body temperatures and numbers of each species. Approximately 76 percent of the measurements were made on rainbow and brown trout, since these species accounted for 74 percent of the catch. Body temperatures of most fish were intermediate between intake and discharge temperatures. Results suggested that each species has rather specific seasonal temperature requirements and that the maximum discharge temperature was normally avoided by feeding fish

  19. Demonstration of high performance negative central magnetic shear discharges on the DIII-D tokamak

    International Nuclear Information System (INIS)

    Rice, B.W.; Burrell, K.H.; Lao, L.L.

    1996-01-01

    Reliable operation of discharges with negative central magnetic shear has led to significant increases in plasma performance and reactivity in both low confinement, L-mode, and high confinement, H-mode, regimes in the DIII-D tokamak. Using neutral beam injection early in the initial current ramp, a large range of negative shear discharges have been produced with durations lasting up to 3.2 s. The total non- inductive current (beam plus bootstrap) ranges from 50% to 80% in these discharges. In the region of shear reversal, significant peaking of the toroidal rotation [f φ ∼ 30-60 kHz] and ion temperature [T i (0) ∼ 15-22 keV] profiles are observed. In high power discharges with an L-mode edge, peaked density profiles are also observed. Confinement enhancement factors up to H ≡ τ E /τ ITER-89P ∼ 2.5 with an L-mode edge, and H ∼ 3.3 in an Edge Localized Mode (ELM)-free H-mode, are obtained. Transport analysis shows both ion thermal diffusivity and particle diffusivity to be near or below standard neoclassical values in the core. Large pressure peaking in L- mode leads to high disruptivity with Β N ≡ Β T /(I/aB) ≤ 2.3, while broader pressure profiles in H- mode gives low disruptivity with Β N ≤ 4.2

  20. Thermal Stress FE Analysis of Large-scale Gas Holder Under Sunshine Temperature Field

    Science.gov (United States)

    Li, Jingyu; Yang, Ranxia; Wang, Hehui

    2018-03-01

    The temperature field and thermal stress of Man type gas holder is simulated by using the theory of sunshine temperature field based on ASHRAE clear-sky model and the finite element method. The distribution of surface temperature and thermal stress of gas holder under the given sunshine condition is obtained. The results show that the thermal stress caused by sunshine can be identified as one of the important factors for the failure of local cracked oil leakage which happens on the sunny side before on the shady side. Therefore, it is of great importance to consider the sunshine thermal load in the stress analysis, design and operation of large-scale steel structures such as the gas holder.

  1. Comparative evaluation of effects of ozonated and chlorinated thermal discharges on estuarine and freshwater organisms

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, C.R.; Sugam, R.; Meldrim, J.W.; Holmstrom, E.R.; Balog, G.E.

    1980-08-01

    As a part of a program at PSE and G designed to examine the feasibility of ozonation as an alternative to chlorination for control of biofouling in once-through cooling systems, the biological effects of ozonated and chlorinated thermal discharges were evaluated with estuarine and freshwater organisms. Mortality at salinities between 0.5 to 2.5 ppt with mummichog and white perch indicated greater toxicity for chlorine while the alewife, spottail shiner, rainbow trout and white perch in freshwater were more sensitive to ozone. Behavioral and physograhic results were consistent with those observed in toxicity studies. Initial cough response and avoidance concentrations of mummicog and white perch in estuarine waters were lower when exposed to chlorine than to ozone. In freshwater, blueback herring, alewife, rainbow trout, spottail shiner, banded killifish, and white perch avoided lower concentrations of ozone than chlorine.

  2. A Review of Online Partial Discharge Measurement of Large Generators

    Directory of Open Access Journals (Sweden)

    Yuanlin Luo

    2017-10-01

    Full Text Available Online partial discharge (PD measurements have long been used as an effective means to assess the condition of the stator windings of large generators. An increase in the use of PD online measurement systems during the last decade is evident. Improvements in the detection capabilities are partly the reason for the increased popularity. Another reason has been the development of digital signal processing techniques. In addition, rapid progress is being made in automated single PD source classification. However, there are still some factors hindering wider application of the system, such as the complex PD mechanism and PD pulse propagation in stator windings, the presence of detrimental noise and disturbances on-site, and multiple PD sources occurring simultaneously. To avoid repetition of past work and to provide an overview for fresh researchers in this area, this paper presents a comprehensive survey of the state-of-the-art knowledge on PD mechanism, PD pulse propagation in stator windings, PD signal detection methods and signal processing techniques. Areas for further research are also presented.

  3. Some aspects of cooling water discharges and environmental enhancement

    International Nuclear Information System (INIS)

    Grimaas, U.

    1976-01-01

    As a consequence of the effects of cooling water discharge on the environment, the siting of nuclear power plants is approached with cautiousness. The pros and cons are discussed of siting near bodies of good quality water or in more densely populated or industrial areas. Properties and effects of thermal discharges are elaborated. The effects of heat on the activity of individual organisms, on the accumulation of organic material, on the mineralization rate of organic matter and on the transport of oxygen all have influences on recipient water bodies. Examples of siting Swedish thermal power stations are described and these indicate some negative effects. However, the results do not repudiate the possibility of good effects from the design of new cooling water intake and discharge systems that would speed up the mineralization of organic matters by addition of heat and oxygen. It is concluded that, when choosing between possible sites, areas should be selected where the available energy of the discharge can be used to improve water quality. (author)

  4. A review on lithium-ion power battery thermal management technologies and thermal safety

    Science.gov (United States)

    An, Zhoujian; Jia, Li; Ding, Yong; Dang, Chao; Li, Xuejiao

    2017-10-01

    Lithium-ion power battery has become one of the main power sources for electric vehicles and hybrid electric vehicles because of superior performance compared with other power sources. In order to ensure the safety and improve the performance, the maximum operating temperature and local temperature difference of batteries must be maintained in an appropriate range. The effect of temperature on the capacity fade and aging are simply investigated. The electrode structure, including electrode thickness, particle size and porosity, are analyzed. It is found that all of them have significant influences on the heat generation of battery. Details of various thermal management technologies, namely air based, phase change material based, heat pipe based and liquid based, are discussed and compared from the perspective of improving the external heat dissipation. The selection of different battery thermal management (BTM) technologies should be based on the cooling demand and applications, and liquid cooling is suggested being the most suitable method for large-scale battery pack charged/discharged at higher C-rate and in high-temperature environment. The thermal safety in the respect of propagation and suppression of thermal runaway is analyzed.

  5. Effect of Topography on Subglacial Discharge and Submarine Melting During Tidewater Glacier Retreat

    Science.gov (United States)

    Amundson, J. M.; Carroll, D.

    2018-01-01

    To first order, subglacial discharge depends on climate, which determines precipitation fluxes and glacier mass balance, and the rate of glacier volume change. For tidewater glaciers, large and rapid changes in glacier volume can occur independent of climate change due to strong glacier dynamic feedbacks. Using an idealized tidewater glacier model, we show that these feedbacks produce secular variations in subglacial discharge that are influenced by subglacial topography. Retreat along retrograde bed slopes (into deep water) results in rapid surface lowering and coincident increases in subglacial discharge. Consequently, submarine melting of glacier termini, which depends on subglacial discharge and ocean thermal forcing, also increases during retreat into deep water. Both subglacial discharge and submarine melting subsequently decrease as glacier termini retreat out of deep water and approach new steady state equilibria. In our simulations, subglacial discharge reached peaks that were 6-17% higher than preretreat values, with the highest values occurring during retreat from narrow sills, and submarine melting increased by 14% for unstratified fjords and 51% for highly stratified fjords. Our results therefore indicate that submarine melting acts in concert with iceberg calving to cause tidewater glacier termini to be unstable on retrograde beds. The full impact of submarine melting on tidewater glacier stability remains uncertain, however, due to poor understanding of the coupling between submarine melting and iceberg calving.

  6. Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems

    Directory of Open Access Journals (Sweden)

    Franco Tassi

    2010-03-01

    Full Text Available The composition of non-methane organic volatile compounds (VOCs determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  7. Origin and distribution of thiophenes and furans in gas discharges from active volcanoes and geothermal systems.

    Science.gov (United States)

    Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando

    2010-03-31

    The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.

  8. Simulation of impurity transport in the peripheral plasma due to the emission of dust in long pulse discharges on the Large Helical Device

    Directory of Open Access Journals (Sweden)

    M. Shoji

    2017-08-01

    Full Text Available Two different plasma termination processes by dust emission were observed in long pulse discharges in the Large Helical Device. One is a plasma termination caused by large amounts of carbon dust released from a lower divertor region. The other is termination caused by stainless steel (iron dust emission from the surface of a helical coil can. The effect of the dust emission on the sustainment of the long pulse discharges are investigated using a three-dimensional edge plasma transport code (EMC3-EIRENE coupled with a dust transport code (DUSTT. The simulation shows that the plasma is more influenced by the iron dust emission from the helical coil can than by the carbon dust emission from the divertor region. The simulation revealed that the plasma flow in divertor legs is quite effective for preventing dust from terminating the long pulse discharges.

  9. Large Eddy Simulation of a thermal mixing tee in order to assess the thermal fatigue

    International Nuclear Information System (INIS)

    Galpin, J.; Simoneau, J.P.

    2011-01-01

    Highlights: → In this study, we perform a Large Eddy Simulation of a mixing tee, for which experimental thermal statistics are available. → A special methodology has been set up for comparing properly the fluctuations with the experiment. → A comparison between the Smagorinsky and the structure-function sub-grid scale model is achieved out. → Slight better predictions are obtained with the structure-function model. → The possibility to reduce the computational domain by prescribing synthetic turbulence at the inlet is tested. First results are encouraging and underline the advantage of considering this technique instead of a standard noise at the entrance of the domain. - Abstract: The present paper deals with thermal fatigue phenomenon, and more particularly with the numerical simulation using Large Eddy Simulation technique of a mixing tee, for which experimental thermal statistics are available. The sensitivity to the sub-grid scale closure is first evaluated by comparing the experimental statistics with the numerical results obtained via both the Smagorinsky and the structure-function models. Because of a difference of temporal resolution between the experiment and the simulation, the direct comparison of the fluctuations is not possible. Therefore, a methodology based on filtering the numerical results is proposed in order to achieve a proper comparison. The comparison of the numerical results with the experiment suggests that slight better predictions are obtained with the structure-function model even if the dependency of the results to the sub-grid scale model is low. Then, the possibility to reduce the fluid computational domain by prescribing synthetic turbulence at the inlet is tested. First results are encouraging and underline the advantage of considering this technique instead of a standard noise at the entrance of the domain. All the simulations are conducted with the commercial CFD code STAR-CD.

  10. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

    Directory of Open Access Journals (Sweden)

    D. K. Hare

    2017-11-01

    Full Text Available Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns

  11. Hydrogeological controls on spatial patterns of groundwater discharge in peatlands

    Science.gov (United States)

    Hare, Danielle K.; Boutt, David F.; Clement, William P.; Hatch, Christine E.; Davenport, Glorianna; Hackman, Alex

    2017-11-01

    Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns may allow resource

  12. Thermal effect of lubricating oil in positive-displacement air compressors

    International Nuclear Information System (INIS)

    Valenti, Gianluca; Colombo, Luigi; Murgia, Stefano; Lucchini, Andrea; Sampietro, Andrea; Capoferri, Andrea; Araneo, Lucio

    2013-01-01

    The isentropic efficiency of positive-displacement compressors may be improved in order to follow an increasing demand for energy savings. This work analyzes the thermal effect of the lubricating oil presence in the air during compression with the scope of exploiting it as a thermal ballast to mitigate both the gas temperature rise and its compression work. The bibliographic review shows that other authors suggested that oil can have positive effects if properly injected. Here an energy balance analysis is executed with the scope of deriving relations for the gas–liquid compression in analogy with those typical for the gas-only compression and of confirming that ideally the liquid presence may have beneficial effects, making the gas–liquid compression even better than 1- and 2-time intercooled gas compressions. Given these positive results, a heat transfer analysis is conducted to model the thermal interaction between gas and oil droplets within a mid-size rotary vane air compressor. A droplet diameter of the order of 100 μm leads to large reductions of both temperature increase and compression work: air can exit the discharge port at a temperature as low as 60 °C and compression work can be lowered by 23–28% with respect to conventional compressors. Finally, a test rig is constructed and operated to investigate a large-flow and large-angle oil nozzle taken from the market showing that, at the operating conditions of a compressor, oil breaks up into small droplets and undefined structures with large exchange surfaces. -- Highlights: ► Exploitation of thermal effect of oil in gas compressors is assessed numerically. ► Oil in 100 μm-diameter droplets mitigates effectively the gas temperature rise. ► Discharge temperature and compression work result to be much smaller than typical. ► An experimental setup is used to investigate oil atomization via commercial nozzles. ► A tested nozzle creates fine oil droplets and structures at conditions of

  13. CO2 Dissociation by Low Current Gliding Discharge in the Reverse Vortex Flow

    Science.gov (United States)

    Gutsol, Alexander

    2012-10-01

    If performed with high energy efficiency, plasma-chemical dissociation of carbon dioxide can be a way of converting and storing energy when there is an excess of electric energy, for example generated by solar elements of wind turbines. CO2 dissociation with efficiency of up to 90% was reported earlier for low pressure microwave discharge in supersonic flow. A new plasma-chemical system uses a low current gliding discharge in the reverse vortex flow of plasma gas. The system is a development of the Gliding Arc in Tornado reactor. The system was used to study dissociation of CO2 in wide ranges of the following experimental parameters: reactor pressure (15-150 kPa), discharge current (50-500 mA), gas flow rate (3-30 liters per minute), and electrode gap length (1-10 cm). Additionally, the effect of thermal energy recuperation on CO2 dissociation efficiency was tested. Plasma chemical efficiency of CO2 dissociation is very low (about 3%) in a short discharge at low pressures (about 15 kPa) when it is defined by electronic excitation. The highest efficiency (above 40%) was reached at pressures 50-70 kPa in a long discharge with thermal energy recuperation. It means that the process is controlled by thermal dissociation with subsequent effective quenching. Plasma chemical efficiency was determined from the data of chromatographic analysis and oscilloscope electric power integration, and also was checked calorimetrically by the thermal balance of the system.

  14. Large scale Tesla coil guided discharges initiated by femtosecond laser filamentation in air

    Science.gov (United States)

    Arantchouk, L.; Point, G.; Brelet, Y.; Prade, B.; Carbonnel, J.; André, Y.-B.; Mysyrowicz, A.; Houard, A.

    2014-07-01

    The guiding of meter scale electric discharges produced in air by a Tesla coil is realized in laboratory using a focused terawatt laser pulse undergoing filamentation. The influence of the focus position, the laser arrival time, or the gap length is studied to determine the best conditions for efficient laser guiding. Discharge parameters such as delay, jitter, and resistance are characterized. An increase of the discharge length by a factor 5 has been achieved with the laser filaments, corresponding to a mean breakdown field of 2 kV/cm for a 1.8 m gap length. Consecutive guided discharges at a repetition rate of 10 Hz are also reported.

  15. Influence of thermal discharges on the distribution of macroflora and fauna. Humboldt Bay Nuclear Power Plant, California

    International Nuclear Information System (INIS)

    Adams, J.R.

    1975-01-01

    Populations of benthic and epifaunal macro-organisms living in the area influenced by the thermal discharge of the steam-electric power plant at Humboldt Bay, California, were analyzed in 1971 and 1972 to determine if differences in distribution could be attributed to the effluent. Relicated benthic samples were collected with a Ponar grab at 20 stations in the bay and at 4 stations in the canals leading to and from the power plant. Comparisons of epifaunal plants and animals in a rocky intertidal zone were made at 13 permanent transects spaced at various distances on either side of the discharge. Species richness in the intertidal was positively correlated with increased temperature in 13 percent of the possible combinations of tide level and diversity. Individual species were positively correlated with increased temperatures for 19 percent of the plant comparisons, and for 16.3 percent of the animal comparisons. Comparisons of populations of individual species in the heated intertidal zone with those in a control zone indicated differences in 26.2 percent of the plant surveys, and 23.2 percent of the animal surveys. Differences were positively related to the increased temperature in 90.5 percent of the comparisons. Proportions of eurythermal plants or animals in the heated areas of the intertidal zone did not differ significantly from proportions in other areas in 4 different survey periods. With the possible exception of one species, there was no conclusive evidence that any of the 132 species found in the intertidal area at Humboldt Bay was eliminated from the heated area surrounding the discharge of the power plant

  16. Observation of thermal plumes from submerged discharges in the Great Lakes and their implications for modeling and monitoring

    International Nuclear Information System (INIS)

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

    1977-01-01

    Measurements of thermal plumes from submerged discharges of power plant cooling waters into the Great Lakes provide the opportunity to view the mixing processes at prototype scales and to observe the effects of the ambient environment on those processes. Examples of thermal plume behavior in Great Lakes' ambient environments are presented to demonstrate the importance of measurements of the detailed structure of the ambient environment, as well as of the plumes, for interpretation of prototype data for modeling and monitoring purposes. The examples are drawn from studies by Argonne National Laboratory (ANL) at the Zion Nuclear PowerStation and the D. C. Cook Nuclear Plant on Lake Michigan and at the J. A. FitzPatrick Nuclear Power Plant on Lake Ontario. These studies included measurements of water temperatures from a moving boat which provide a quasi-synoptic view of the three-dimensional temperature structure of the thermal plume and ambient water environment. Additional measurements of water velocities, which are made with continuously recording, moored, and profiling current meters, and of wind provide data on the detailed structure of the ambient environment. The detailed structure of the ambient environment, in terms of current, current shear, variable winds, and temperature stratification, often influence greatly thermal plume behavior. Although predictive model techniques and monitoring objectives often ignore the detailed aspects of the ambient environment, useful interpretation of prototype data for model evaluation or calibration and monitoring purposes requires detailed measurement of the ambient environment. Examination of prototype thermal plume data indicates that, in several instances, attention to only the gross characteristics of the ambient environment can be misleading and could result in significant errors in model calibration and extrapolation of data bases gathered in monitoring observations

  17. Interacting effects of discharge and channel morphology on transport of semibuoyant fish eggs in large, altered river systems.

    Directory of Open Access Journals (Sweden)

    Thomas A Worthington

    Full Text Available Habitat fragmentation and flow regulation are significant factors related to the decline and extinction of freshwater biota. Pelagic-broadcast spawning cyprinids require moving water and some length of unfragmented stream to complete their life cycle. However, it is unknown how discharge and habitat features interact at multiple spatial scales to alter the transport of semi-buoyant fish eggs. Our objective was to assess the relationship between downstream drift of semi-buoyant egg surrogates (gellan beads and discharge and habitat complexity. We quantified transport time of a known quantity of beads using 2-3 sampling devices at each of seven locations on the North Canadian and Canadian rivers. Transport time was assessed based on median capture time (time at which 50% of beads were captured and sampling period (time period when 2.5% and 97.5% of beads were captured. Habitat complexity was assessed by calculating width∶depth ratios at each site, and several habitat metrics determined using analyses of aerial photographs. Median time of egg capture was negatively correlated to site discharge. The temporal extent of the sampling period at each site was negatively correlated to both site discharge and habitat-patch dispersion. Our results highlight the role of discharge in driving transport times, but also indicate that higher dispersion of habitat patches relates to increased retention of beads within the river. These results could be used to target restoration activities or prioritize water use to create and maintain habitat complexity within large, fragmented river systems.

  18. Thermal large Eddy simulations and experiments in the framework of non-isothermal blowing

    International Nuclear Information System (INIS)

    Brillant, G.

    2004-06-01

    The aim of this work is to study thermal large-eddy simulations and to determine the nonisothermal blowing impact on a turbulent boundary layer. An experimental study is also carried out in order to complete and validate simulation results. In a first time, we developed a turbulent inlet condition for the velocity and the temperature, which is necessary for the blowing simulations.We studied the asymptotic behavior of the velocity, the temperature and the thermal turbulent fluxes in a large-eddy simulation point of view. We then considered dynamics models for the eddy-diffusivity and we simulated a turbulent channel flow with imposed temperature, imposed flux and adiabatic walls. The numerical and experimental study of blowing permitted to obtain to the modifications of a thermal turbulent boundary layer with the blowing rate. We observed the consequences of the blowing on mean and rms profiles of velocity and temperature but also on velocity-velocity and velocity-temperature correlations. Moreover, we noticed an increase of the turbulent structures in the boundary layer with blowing. (author)

  19. Fast Thermal Runaway Detection for Lithium-Ion Cells in Large Scale Traction Batteries

    Directory of Open Access Journals (Sweden)

    Sascha Koch

    2018-03-01

    Full Text Available Thermal runaway of single cells within a large scale lithium-ion battery is a well-known risk that can lead to critical situations if no counter measures are taken in today’s lithium-ion traction batteries for battery electric vehicles (BEVs, plug-in hybrid electric vehicles (PHEV and hybrid electric vehicles (HEVs. The United Nations have published a draft global technical regulation on electric vehicle safety (GTR EVS describing a safety feature to warn passengers in case of a thermal runaway. Fast and reliable detection of faulty cells undergoing thermal runaway within the lithium-ion battery is therefore a key factor in battery designs for comprehensive passenger safety. A set of various possible sensors has been chosen based on the determined cell thermal runaway impact. These sensors have been tested in different sized battery setups and compared with respect to their ability of fast and reliable thermal runaway detection and their feasibility for traction batteries.

  20. Properties of dielectric barrier discharges in different arrangements

    International Nuclear Information System (INIS)

    Pietsch, G.J.

    2001-01-01

    Dielectric barrier discharges (DBDs) occur in arrangements where at least one dielectric is positioned in a gas space in between conducting electrodes. When breakdown field strength is reached in such a device, charge carriers are created in the gas region, accelerated, multiplied and finally collected on the surface(s) of the dielectric(s). The charge accumulation on the dielectric creates a counter field to that resulting from the power supply and as all of these processes are rather fast, the discharge quenches rapidly. The dielectric has two tasks, it limits the transferred charge and by this the energy conversion and distributes the discharge over the electrode area. That is why DBDs are non-thermal discharges which exist even at atmospheric pressure

  1. H-ADCP discharge monitoring of a large tropical river

    NARCIS (Netherlands)

    Hidayat, H.; Sassi, M.G.; Vermeulen, B.

    2012-01-01

    River flow can be continuously monitored through velocity measurements with an acoustic Doppler current profiler, deployed horizontally at a river bank (H-ADCP). This approach was adopted to obtain continuous discharge estimates at two cross-sections in the River Mahakam, i.e. at an upstream station

  2. Development of a discharge-heated plasma tube

    International Nuclear Information System (INIS)

    Cha, Byung Heon; Jin, J. T.; Nam, S. M.; Lee, S. M.; Choi, H. L.; Ko, D. K.; Kim, S. H.; Lee, Y. B.; Choi, Y. S.; Lee, J. M.; Lee, C. K.; Lee, H. G.; Lee, H. C.; Jung, S. M.; Kim, Y. J.; Choi, G. S.; Son, N. G.

    1999-12-01

    A discharge-heated type plasma tube was designed and constructed. The structure of the laser plasma tube was designed to be easy in maintenance. The inside plasma tube was made of a high purity alumina and the thermal insulator tube was made of a porous alumina. The electrode made of tungsten was chosen for the endurance of high discharge voltage. AR coated windows were used as laser windows. A proto-type laser plasma tube was tested with a pulse modulator. An average laser output power was 32 W at the discharge voltage of 28 kV, the electric input power of 4.6 kW, and the pulse repetition rates of 10 kHz. (author)

  3. Modeling the response of Northwest Greenland to enhanced ocean thermal forcing and subglacial discharge

    Science.gov (United States)

    Morlighem, M.; Wood, M.; Seroussi, H. L.; Bondzio, J. H.; Rignot, E. J.

    2017-12-01

    Glacier-front dynamics is an important control on Greenland's ice mass balance. Warm and salty Atlantic water, which is typically found at a depth below 200-300 m, has the potential to trigger ice-front retreats of marine-terminating glaciers, and the corresponding loss in resistive stress leads to glacier acceleration and thinning. It remains unclear, however, which glaciers are currently stable but may retreat in the future, and how far inland and how fast they will retreat. Here, we quantify the sensitivity and vulnerability of marine-terminating glaciers along the Northwest coast of Greenland (from 72.5° to 76°N) to ocean forcing using the Ice Sheet System Model (ISSM), and its new ice front migration capability. We rely on the ice melt parameterization from Rignot et al. 2016, and use ocean temperature and salinity from high-resolution ECCO2 simulations on the continental shelf to constrain the thermal forcing. The ice flow model includes a calving law based on a Von Mises criterion. We investigate the sensitivity of Northwest Greenland to enhanced ocean thermal forcing and subglacial discharge. We find that some glaciers, such as Dietrichson Gletscher or Alison Gletscher, are sensitive to small increases in ocean thermal forcing, while others, such as Illullip Sermia or Qeqertarsuup Sermia, are very difficult to destabilize, even with a quadrupling of the melt. Under the most intense melt experiment, we find that Hayes Gletscher retreats by more than 50 km inland into a deep trough and its velocity increases by a factor of 10 over only 15 years. The model confirms that ice-ocean interactions are the triggering mechanism of glacier retreat, but the bed controls its magnitude. This work was performed at the University of California Irvine under a contract with the National Aeronautics and Space Administration, Cryospheric Sciences Program (#NNX15AD55G), and the National Science Foundation's ARCSS program (#1504230).

  4. Electrical and spectroscopic characterization of a surgical argon plasma discharge

    International Nuclear Information System (INIS)

    Keller, Sandra; Neugebauer, Alexander; Bibinov, Nikita; Awakowicz, Peter

    2013-01-01

    For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage-current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.

  5. Debinding of injected parts using an abnormal glow discharge

    International Nuclear Information System (INIS)

    Santos, M.A.; Maliska, A.M.; Klein, A.N.; Ristow, W.; Muzart, J.L.R.

    2005-01-01

    Results of binder removal of injected PM components using plasma technology are presented. The samples were injected with 55.18 vol.% of iron powder, 23.57 vol.% of paraffin and 21.25 vol.%. of polypropylene and treated in hydrogen and argon discharges at a pressure of 400 Pa (3 Torr), varying temperature and treatment times. The discharge was generated by a pulsed power source in a confined anode-cathode geometry. The outer electrode consisted of the cathode and was heated by the bombardment of ions accelerated in the cathode region. The sample was placed on an inner holder and heated by thermal radiation. Three different configurations of electrodes were used in order to evaluate the influence of electron bombardment on the sample surface, the interaction of the reactive species generated in the discharge with the binder and thermal effects on the dissociation of the organic molecules. Samples were characterized by mass loss and energy dispersive X-ray (EDX) analysis. The results show that the electron bombardment added to the interaction of reactive species on the sample surface significantly activated the binder removal. By using a laboratory scale plasma reactor, it was shown that the binder extraction and pre-sintering cycle could be performed in a single thermal cycle lasting approximately 200 min

  6. [Study on plasma temperature of a large area surface discharge by optical emission spectrum].

    Science.gov (United States)

    Dong, Li-Fang; Tong, Guo-Liang; Zhang, Yu; Zhou, Bin

    2014-04-01

    A large area surface discharge was realized in air/argon gas mixture by designing a discharge device with water electrodes. By using optical emission spectrum, the variations of the molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature as a function of the gas pressure were studied. The nitrogen molecular vibrational temperature was calculated according to the emission line of the second positive band system of the nitrogen molecule (C3 pi(u) --> B 3 pi(g)). The electronic excitation temperature was obtained by using the intensity ratio of Ar I 763.51 nm (2P(6) --> 1S(5)) to Ar I 772.42 nm (2P(2) --> 1S(3)). The changes in the mean energy of electron were studied by the relative intensity ratio of the nitrogen molecular ion 391.4 nm to nitrogen 337.1 nm. It was found that the intensity of emission spectral line increases with the increase in the gas pressure, meanwhile, the outline and the ratios of different spectral lines intensity also change. The molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature decrease as the gas pressure increases from 0.75 x 10(5) Pa to 1 x 10(5) Pa.

  7. Goodenough Spring, Texas, USA: Discharge and water chemistry of a large spring deeply submerged under the binational Amistad Reservoir

    Science.gov (United States)

    Kamps, Ray H.; Tatum, Gregg S.; Gault, Mike; Groeger, Alan W.

    2009-06-01

    Goodenough Spring (Texas, USA) is a large spring near the border of the American state of Texas and the Mexican state of Coahuila, discharging into the international Amistad Reservoir on the river Rio Grande (Rio Bravo). Discharge was routinely measured from 1928 until 1968 to partition the flow of the river between the two countries in accordance with water-use treaties. Samples were analyzed for water-quality parameters in 1967-1968 prior to inundation under 45 m of Amistad Reservoir in 1968. Subsequently, discharge has been estimated indirectly by the International Boundary and Water Commission (IBWC). For the first direct measurements of the spring in 37 years, velocity and cross-sectional measurements were made and water samples collected in the summer of 2005 using advanced self-contained underwater breathing apparatus (SCUBA) techniques. Spring discharge was calculated at 2.03 m3 s-1, approximately one-half of the historical mean of 3.94 m3 s-1. In situ and laboratory analyses of samples for temperature, pH, dissolved oxygen, specific conductance, alkalinity, nitrate-nitrogen, dissolved solids, chloride, sulfate, fluoride, phosphorus, calcium, sodium, potassium, magnesium, and iron showed the water quality to be very good for human consumption and crop irrigation. Measurement values are relatively unchanged from those reported 37 years prior.

  8. RELAPS choked flow model and application to a large scale flow test

    International Nuclear Information System (INIS)

    Ransom, V.H.; Trapp, J.A.

    1980-01-01

    The RELAP5 code was used to simulate a large scale choked flow test. The fluid system used in the test was modeled in RELAP5 using a uniform, but coarse, nodalization. The choked mass discharge rate was calculated using the RELAP5 choked flow model. The calulations were in good agreement with the test data, and the flow was calculated to be near thermal equilibrium

  9. Gas Temperature Measurement in a Glow Discharge Plasma

    Science.gov (United States)

    Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

    2009-10-01

    In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

  10. Thermally stimulated discharge current (TSDC) and dielectric ...

    Indian Academy of Sciences (India)

    Unknown

    2001-10-09

    Oct 9, 2001 ... Measurements of TSDC and dielectric constant, ε′, have been ... Keywords. Semiconducting glass; TSDC; trap energy; dielectric constant. 1. ... determination of mean depth of the internal charge, activation ... thermal charging, viz. (i) internal ... the basis of d.c. conductivity and short range Na+ ion motion.

  11. A pseudo three-dimensional electrochemical–thermal model of a prismatic LiFePO4 battery during discharge process

    International Nuclear Information System (INIS)

    Xu, Meng; Zhang, Zhuqian; Wang, Xia; Jia, Li; Yang, Lixin

    2015-01-01

    A lithium ion battery consists of numerous electrochemical cell units. Thermal and electrical behaviors of these local cell units have great influence on the battery's performance and safety. To study the relationship between the cell units and the battery cell, a pseudo 3D (three-dimensional) model was developed for a prismatic LiFePO 4 battery by coupling the mass, charge, and energy conservations, as well as the cell electrochemical kinetics. The model treated the battery with current collecting tabs as 3D and the local cell units as 1D. Both electrochemical and thermal characteristics of the battery were studied by using this simplified model during the discharge process. A uniformity index characterizing the SOC (state of charge) distributions among 1D cell units was also introduced. This index was used to investigate the effects of the tab placement on the uniformity of the battery cell. The placement of the positive and negative current collecting tabs on the prismatic battery was found to have a significant effect on the distributions of its potential and local reaction rates, which therefore affect the heat generation rate, and thus the temperature distribution within the battery. - Highlights: • We develop a 3D electrochemical–thermal model for a prismatic LiFePO 4 battery. • Reaction rate distribution is not in a uniform mode due to electrical gradient. • The higher reaction rate, the more quickly the heat generated in local regions. • The temperature is higher in the region close to the tabs than other regions. • Tabs placed on opposite sides will improve the uniformity of thermal distribution

  12. Thermal performance analysis of a phase change thermal storage unit for space heating

    Energy Technology Data Exchange (ETDEWEB)

    Halawa, E.; Saman, W. [Institute for Sustainable Systems and Technologies School of Advanced Manufacturing and Mechanical Engineering, University of South Australia, Mawson Lakes SA 5095 (Australia)

    2011-01-15

    This paper presents the results of a comprehensive numerical study on the thermal performance of an air based phase change thermal storage unit (TSU) for space heating. The unit is designed for integration into space heating and cooling systems. The unit consists of a number of one dimensional phase change material (PCM) slabs contained in a rectangular duct where air passes between the slabs. The numerical analysis was based on an experimentally validated model. A parametric study has been carried out including the study on the effects of charge and discharge temperature differences, air mass flow rate, slab thicknesses, air gaps and slab dimensions on the air outlet temperatures and heat transfer rates of the thermal storage unit. The paper introduces and discusses quantities called charge and discharge temperature differences which play an important role in the melting and freezing processes. (author)

  13. Characteristics of a corona discharge with a hot corona electrode

    International Nuclear Information System (INIS)

    Kulumbaev, E. B.; Lelevkin, V. M.; Niyazaliev, I. A.; Tokarev, A. V.

    2011-01-01

    The effect of the temperature of the corona electrode on the electrical characteristics of a corona discharge was studied experimentally. A modified Townsend formula for the current-voltage characteristic of a one-dimensional corona is proposed. Gasdynamic and thermal characteristics of a positive corona discharge in a coaxial electrode system are calculated. The calculated results are compared with the experimental data.

  14. Coupled electrochemical thermal modelling of a novel Li-ion battery pack thermal management system

    International Nuclear Information System (INIS)

    Basu, Suman; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Sohn, Dong Kee; Yeo, Taejung

    2016-01-01

    Highlights: • Three-dimensional electrochemical thermal model of Li-ion battery pack using computational fluid dynamics (CFD). • Novel pack design for compact liquid cooling based thermal management system. • Simple temperature estimation algorithm for the cells in the pack using the results from the model. • Sensitivity of the thermal performance to contact resistance has been investigated. - Abstract: Thermal management system is of critical importance for a Li-ion battery pack, as high performance and long battery pack life can be simultaneously achieved when operated within a narrow range of temperature around the room temperature. An efficient thermal management system is required to keep the battery temperature in this range, despite widely varying operating conditions. A novel liquid coolant based thermal management system, for 18,650 battery pack has been introduced herein. This system is designed to be compact and economical without compromising safety. A coupled three-dimensional (3D) electrochemical thermal model is constructed for the proposed Li-ion battery pack. The model is used to evaluate the effects of different operating conditions like coolant flow-rate and discharge current on the pack temperature. Contact resistance is found to have the strongest impact on the thermal performance of the pack. From the numerical solution, a simple and novel temperature correlation of predicting the temperatures of all the individual cells given the temperature measurement of one cell is devised and validated with experimental results. Such coefficients have great potential of reducing the sensor requirement and complexity in a large Li-ion battery pack, typical of an electric vehicle.

  15. Thermal power plant efficiency enhancement with Ocean Thermal Energy Conversion

    International Nuclear Information System (INIS)

    Soto, Rodrigo; Vergara, Julio

    2014-01-01

    In addition to greenhouse gas emissions, coastal thermal power plants would gain further opposition due to their heat rejection distressing the local ecosystem. Therefore, these plants need to enhance their thermal efficiency while reducing their environmental offense. In this study, a hybrid plant based on the principle of Ocean Thermal Energy Conversion was coupled to a 740 MW coal-fired power plant project located at latitude 28°S where the surface to deepwater temperature difference would not suffice for regular OTEC plants. This paper presents the thermodynamical model to assess the overall efficiency gained by adopting an ammonia Rankine cycle plus a desalinating unit, heated by the power plant condenser discharge and refrigerated by cold deep seawater. The simulation allowed us to optimize a system that would finally enhance the plant power output by 25–37 MW, depending on the season, without added emissions while reducing dramatically the water temperature at discharge and also desalinating up to 5.8 million tons per year. The supplemental equipment was sized and the specific emissions reduction was estimated. We believe that this approach would improve the acceptability of thermal and nuclear power plant projects regardless of the plant location. -- Highlights: • An Ocean Thermal Energy Conversion hybrid plant was designed. • The waste heat of a power plant was delivered as an OTEC heat source. • The effect of size and operating conditions on plant efficiency were studied. • The OTEC implementation in a Chilean thermal power plant was evaluated. • The net efficiency of the thermal power plant was increased by 1.3%

  16. Periodic long-range transport in a large volume dc glow discharge dusty plasma

    International Nuclear Information System (INIS)

    Thomas, Edward Jr.; Amatucci, William E.; Compton, Christopher; Christy, Brian; Jackson, Jon David

    2003-01-01

    In an earlier paper, the authors reported on observations of a variety of particle transport phenomena observed in DUPLEX--the DUsty PLasma EXperiment at the Naval Research Laboratory [E. Thomas, Jr., W. E. Amatucci, C. Compton, and B. Christy, Phys. Plasmas 9, 3154 (2002)]. DUPLEX is a large, transparent polycarbonate cylinder that is 40 cm in radius and 80 cm in height. dc glow discharge argon plasmas are generated in DUPLEX. In this paper, the authors expand upon one particular feature of particle transport in DUPLEX, the long-range (i.e., greater than 15 cm), periodic (T∼2.5 min) transport of suspended alumina particles through the plasma. A detailed description of this particle motion through the plasma is presented. Finally, a qualitative model describing the phenomena that lead to this transport is also given

  17. A geothermal resource in the Puna plateau (Jujuy Province, Argentina): New insights from the geochemistry of thermal fluid discharges

    Science.gov (United States)

    Peralta Arnold, Yesica; Cabassi, Jacopo; Tassi, Franco; Caffe, Pablo; Vaselli, Orlando

    2017-04-01

    Several hydrothermal mineralization and thermal fluid discharges are distributed in the high altitude Puna plateau at the eastern border of the Central Volcanic Zone of the Andes in the Jujuy Province, a region where volcanic explosive activity developed from Oligocene-Miocene to Neogene produced giant calderas and huge ignimbrite deposits. This study presents the geochemical and isotopic composition of thermal fluids discharged from Granada, Vilama, Pairique, Coranzulì and Olaroz zones, which are located between S 22°20'- 23°20' and W 66°- 67°. This aim is to provide insights into the physicochemical features of the deep fluid circulating system in order to have a preliminary indication about the geothermal potential in this area. The occurrence of partially mature Na+-Cl- waters suggests that a deep (>5,000 m b.g.l.) hydrothermal reservoir, hosted within the Paleozoic crystalline basement, represents the main fluid source. Regional tectonics, dominated by S-oriented faulting systems that produced a horst and graben tectonics, as well as NE-, NW- and WE-oriented transverse structures, favour the uprising of the deep-originated fluids, including a significant amount (up to 16%) of mantle He. The dry gas phase mainly consists of CO2 mostly produced from subducted C-bearing organic-rich material. The interaction between meteoric water and Cretaceous, Palaeogene to Miocene sediments at shallow depth gives rise to relatively cold Na+-HCO3-type aquifers. Dissolution of evaporitic surficial deposits (salares), produced by the arid climate of the region, strongly affects the chemistry of the thermal springs in the peripheral zones of the study area. Geothermometry in the Na-K-Ca-Mg system suggests equilibrium temperatures up to 200 °C for the deep aquifer, whereas the H2 geothermometer equilibrates at lower temperatures (from 105 to 155 °C), likely corresponding to those of the shallower aquifer. Although the great depth of the main fluid reservoir represents a

  18. Thermal oxidation of nuclear graphite: A large scale waste treatment option

    Science.gov (United States)

    Jones, Abbie N.; Marsden, Barry J.

    2017-01-01

    This study has investigated the laboratory scale thermal oxidation of nuclear graphite, as a proof-of-concept for the treatment and decommissioning of reactor cores on a larger industrial scale. If showed to be effective, this technology could have promising international significance with a considerable impact on the nuclear waste management problem currently facing many countries worldwide. The use of thermal treatment of such graphite waste is seen as advantageous since it will decouple the need for an operational Geological Disposal Facility (GDF). Particulate samples of Magnox Reactor Pile Grade-A (PGA) graphite, were oxidised in both air and 60% O2, over the temperature range 400–1200°C. Oxidation rates were found to increase with temperature, with a particular rise between 700–800°C, suggesting a change in oxidation mechanism. A second increase in oxidation rate was observed between 1000–1200°C and was found to correspond to a large increase in the CO/CO2 ratio, as confirmed through gas analysis. Increasing the oxidant flow rate gave a linear increase in oxidation rate, up to a certain point, and maximum rates of 23.3 and 69.6 mg / min for air and 60% O2 respectively were achieved at a flow of 250 ml / min and temperature of 1000°C. These promising results show that large-scale thermal treatment could be a potential option for the decommissioning of graphite cores, although the design of the plant would need careful consideration in order to achieve optimum efficiency and throughput. PMID:28793326

  19. Thermal oxidation of nuclear graphite: A large scale waste treatment option.

    Directory of Open Access Journals (Sweden)

    Alex Theodosiou

    Full Text Available This study has investigated the laboratory scale thermal oxidation of nuclear graphite, as a proof-of-concept for the treatment and decommissioning of reactor cores on a larger industrial scale. If showed to be effective, this technology could have promising international significance with a considerable impact on the nuclear waste management problem currently facing many countries worldwide. The use of thermal treatment of such graphite waste is seen as advantageous since it will decouple the need for an operational Geological Disposal Facility (GDF. Particulate samples of Magnox Reactor Pile Grade-A (PGA graphite, were oxidised in both air and 60% O2, over the temperature range 400-1200°C. Oxidation rates were found to increase with temperature, with a particular rise between 700-800°C, suggesting a change in oxidation mechanism. A second increase in oxidation rate was observed between 1000-1200°C and was found to correspond to a large increase in the CO/CO2 ratio, as confirmed through gas analysis. Increasing the oxidant flow rate gave a linear increase in oxidation rate, up to a certain point, and maximum rates of 23.3 and 69.6 mg / min for air and 60% O2 respectively were achieved at a flow of 250 ml / min and temperature of 1000°C. These promising results show that large-scale thermal treatment could be a potential option for the decommissioning of graphite cores, although the design of the plant would need careful consideration in order to achieve optimum efficiency and throughput.

  20. Large area atmospheric-pressure plasma jet

    Science.gov (United States)

    Selwyn, Gary S.; Henins, Ivars; Babayan, Steve E.; Hicks, Robert F.

    2001-01-01

    Large area atmospheric-pressure plasma jet. A plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two planar, parallel electrodes are employed to generate a plasma in the volume therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly spacing the rf-powered electrode. Because of the atmospheric pressure operation, there is a negligible density of ions surviving for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike the situation for low-pressure plasma sources and conventional plasma processing methods.

  1. Formation of self-organized anode patterns in arc discharge simulations

    International Nuclear Information System (INIS)

    Trelles, Juan Pablo

    2013-01-01

    Pattern formation and self-organization are phenomena commonly observed experimentally in diverse types of plasma systems, including atmospheric-pressure electric arc discharges. However, numerical simulations reproducing anode pattern formation in arc discharges have proven exceedingly elusive. Time-dependent three-dimensional thermodynamic non-equilibrium simulations reveal the spontaneous formation of self-organized patterns of anode attachment spots in the free-burning arc, a canonical thermal plasma flow established by a constant dc current between an axi-symmetric electrode configuration in the absence of external forcing. The number of spots, their size and distribution within the pattern depend on the applied total current and on the resolution of the spatial discretization, whereas the main properties of the plasma flow, such as maximum temperatures, velocity and voltage drop, depend only on the former. The sensibility of the solution to the spatial discretization stresses the computational requirements for comprehensive arc discharge simulations. The obtained anode patterns qualitatively agree with experimental observations and confirm that the spots originate at the fringes of the arc–anode attachment. The results imply that heavy-species–electron energy equilibration, in addition to thermal instability, has a dominant role in the formation of anode spots in arc discharges. (paper)

  2. PERSPECTIVE TECHNOLOGIES OF THERMAL HARDENING OF LARGE-SIZE ARTICLES OF TWO-PHASE TITANIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    V. N. Fedulov

    2005-01-01

    Full Text Available The article is dedicated to the development and industrial assimilation of the fundamentally new methods of thermal strengthening of large articles out of hardenable titanic alloys.

  3. Dynamic, large-deflection, inelastic and thermal stress analysis by the finite element method

    International Nuclear Information System (INIS)

    Haisler, W.E.; Stricklin, J.A.

    1975-01-01

    A finite element theory and computer program have been developed for predicting the dynamic, large displacement, inelastic and thermal response of stiffened and layered structures. The dependence of material properties on temperature is explicitly accounted for and any arbitrary, transient mechanical or thermal load history is allowed. The shell may have internal or external stiffeners and be constructed with up to three layers. The equations of motion are developed by using the pseudo force approach to represent all nonlinearities and are then solved by using either the Houbolt method or central differences. Moderately large rotations are allowed. The program is based on an incremental theory of plasticity using the Von Mises yield condition and associated flow rule. The post yield or work-hardening behavior is idealized with either the isotropic hardening or mechanical sublayer models. Two models are utilized since it has been found through comparison with experimental results that isotropic hardening is best for simple loading conditions while the mechanical sublayer model is better for reverse and cyclic loading. Strain-rate effects are also accounted for in the program by using a power-law type model based on the strain rate. The dependence of material properties on temperature is taken into account in the pseudo forces. Young's modulus, Poisson's ratio, thermal coefficient of expansion, the yield stress, and the entire stress strain curve are treated as functions of the applied temperature. Containment vessels subjected to transient and shock-type mechanical and thermal loads have been analyzed

  4. Electric discharge plasmas influence attachment of cultured CHO k1 cells

    NARCIS (Netherlands)

    Kieft, I.E.; Broers, J.L.V.; Caubet-Hilloutou, V.; Slaaf, D.W.; Ramaekers, F.C.S.; Stoffels - Adamowicz, E.

    2004-01-01

    Non-thermal plasmas can be generated by electric discharges in gases. These plasmas are reactive media, capable of superficial treatment of various materials. A novel non-thermal atmospheric plasma source (plasma needle) has been developed and tested. Plasma appears at the end of a metal pin as a

  5. An inverse optimal control problem in the electrical discharge ...

    Indian Academy of Sciences (India)

    Marin Gostimirovic

    2018-05-10

    May 10, 2018 ... Keywords. EDM process; discharge energy; heat source parameters; inverse problem; optimization. 1. Introduction .... ation, thermal modeling of the EDM process would become ..... simulation of die-sinking EDM. CIRP Ann.

  6. Avoidance of thermal effluent by juvenile chinook salmon (Oncorhynchus tshowytscha) and its implications in waste heat management

    International Nuclear Information System (INIS)

    Gray, R.H.

    1977-03-01

    Knowledge of behavioral responses of aquatic organisms to thermal discharges at power plants is essential to evaluate thermal exposure and subsequent effects on survival and ecological success. Instantaneous responses of juvenile salmon that encountered a simulated river-thermal plume interface were assessed in a model raceway with a thermal discharge. Fish movement and response to the discharge were recorded on videotape. Juvenile chinook salmon (Oncorhynchus tshawytscha) tested under three discharge conditions (no plume, ambient plume and heated plume) avoided plume temperatures greater than 9 to 11 0 C above ambient. Fish occasionally oriented to the discharge current, but were not attracted to the thermal component of the plume when plume ΔT's were below the avoidance level of 11 0 C. Fish did not pass to the lower end of the raceway when plume ΔT exceeded 9 to 11 0 C. The responses noted in our experiments suggest organismic behavior may prevent juvenile salmon in nature from experiencing lethal conditions from thermal discharges and have application in waste heat management and utilization

  7. Preliminary study on the modelling of negative leader discharges

    International Nuclear Information System (INIS)

    Arevalo, L; Cooray, V

    2011-01-01

    Nowadays, there is considerable interest in understanding the physics underlying positive and negative discharges because of the importance of improving lightning protection systems and of coordinating the insulation for high voltages. Numerical simulations of positive switching impulses made in long spark gaps in a laboratory are achievable because the physics of the process is reasonably well understood and because of the availability of powerful computational methods. However, the existing work on the simulation of negative switching discharges has been held up by a lack of experimental data and the absence of a full understanding of the physics involved. In the scientific community, it is well known that most of the lightning discharges that occur in nature are of negative polarity, and because of their complexity, the only way to understand them is to generate the discharges in laboratories under controlled conditions. The voltage impulse waveshape used in laboratories is a negative switching impulse. With the aim of applying the available information to a self-consistent physical method, an electrostatic approximation of the negative leader discharge process is presented here. The simulation procedure takes into consideration the physics of positive and negative discharges, considering that the negative leader propagates towards a grounded electrode and the positive leader towards a rod electrode. The simulation considers the leader channel to be thermodynamic, and assumes that the conditions required to generate a thermal channel are the same for positive and negative leaders. However, the magnitude of the electrical charge necessary to reproduce their propagation and thermalization is different, and both values are based on experimental data. The positive and negative streamer development is based on the constant electric field characteristics of these discharges, as found during experimental measurements made by different authors. As a computational tool

  8. Characterization of mean transit time at large springs in the Upper Colorado River Basin, USA: A tool for assessing groundwater discharge vulnerability

    Science.gov (United States)

    Solder, John; Stolp, Bernard J.; Heilweil, Victor M.; Susong, David D.

    2016-01-01

    Environmental tracers (noble gases, tritium, industrial gases, stable isotopes, and radio-carbon) and hydrogeology were interpreted to determine groundwater transit-time distribution and calculate mean transit time (MTT) with lumped parameter modeling at 19 large springs distributed throughout the Upper Colorado River Basin (UCRB), USA. The predictive value of the MTT to evaluate the pattern and timing of groundwater response to hydraulic stress (i.e., vulnerability) is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the springs range from 10 to 15,000 years and 90 % of the cumulative discharge-weighted travel-time distribution falls within the range of 2−10,000 years. Historical variability in discharge was assessed as the ratio of 10–90 % flow-exceedance (R 10/90%) and ranged from 2.8 to 1.1 for select springs with available discharge data. The lag-time (i.e., delay in discharge response to drought conditions) was determined by cross-correlation analysis and ranged from 0.5 to 6 years for the same select springs. Springs with shorter MTTs (<80 years) statistically correlate with larger discharge variations and faster responses to drought, indicating MTT can be used for estimating the relative magnitude and timing of groundwater response. Results indicate that groundwater discharge to streams in the UCRB will likely respond on the order of years to climate variation and increasing groundwater withdrawals.

  9. Experimental characterization of HOTNES: A new thermal neutron facility with large homogeneity area

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN–LNF, via E. Fermi n. 40, 00044 Frascati, Roma (Italy); Sperduti, A. [INFN–LNF, via E. Fermi n. 40, 00044 Frascati, Roma (Italy); ENEA C.R. Frascati, via E. Fermi n. 45, 00044 Frascati, Roma (Italy); Pietropaolo, A.; Pillon, M. [ENEA C.R. Frascati, via E. Fermi n. 45, 00044 Frascati, Roma (Italy); Pola, A. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN–Milano, Via Celoria 16, 20133 Milano (Italy); Gómez-Ros, J.M. [INFN–LNF, via E. Fermi n. 40, 00044 Frascati, Roma (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain)

    2017-01-21

    A new thermal neutron irradiation facility, called HOTNES (HOmogeneous Thermal NEutron Source), was established in the framework of a collaboration between INFN-LNF and ENEA-Frascati. HOTNES is a polyethylene assembly, with about 70 cmx70 cm square section and 100 cm height, including a large, cylindrical cavity with diameter 30 cm and height 70 cm. The facility is supplied by a {sup 241}Am-B source located at the bottom of this cavity. The facility was designed in such a way that the iso-thermal-fluence surfaces, characterizing the irradiation volume, coincide with planes parallel to the cavity bottom. The thermal fluence rate across a given isofluence plane is as uniform as 1% on a disk with 30 cm diameter. Thermal fluence rate values from about 700 cm{sup −2} s{sup −1} to 1000 cm{sup −2} s{sup −1} can be achieved. The facility design, previously optimized by Monte Carlo simulation, was experimentally verified. The following techniques were used: gold activation foils to assess the thermal fluence rate, semiconductor-based active detector for mapping the irradiation volume, and Bonner Sphere Spectrometer to determine the complete neutron spectrum. HOTNES is expected to be attractive for the scientific community involved in neutron metrology, neutron dosimetry and neutron detector testing.

  10. RESOURCE SAVING TECHNOLOGICAL PROCESS OF LARGE-SIZE DIE THERMAL TREATMENT

    Directory of Open Access Journals (Sweden)

    L. A. Glazkov

    2009-01-01

    Full Text Available The given paper presents a development of a technological process pertaining to hardening large-size parts made of die steel. The proposed process applies a water-air mixture instead of a conventional hardening medium that is industrial oil.While developing this new technological process it has been necessary to solve the following problems: reduction of thermal treatment duration, reduction of power resource expense (natural gas and mineral oil, elimination of fire danger and increase of process ecological efficiency. 

  11. Design of an amplifier model accounting for thermal effect in fully aperiodic large pitch fibers

    Science.gov (United States)

    Tragni, K.; Molardi, C.; Poli, F.; Dauliat, R.; Leconte, B.; Darwich, D.; du Jeu, R.; Malleville, M. A.; Jamier, R.; Selleri, S.; Roy, P.; Cucinotta, A.

    2018-02-01

    Yb-doped Photonic Crystal Fibers (PCFs) have triggered a significant power scaling into fiber-based lasers. However thermally-induced effects, like mode instability, can compromise the output beam quality. PCF design with improved Higher Order Mode (HOM) delocalization and effective thermal resilience can contain the problem. In particular, Fully- Aperiodic Large-Pitch Fibers (FA-LPFs) have shown interesting properties in terms of resilience to thermal effects. In this paper the performances of a Yb-doped FA-LPF amplifier are experimentally and numerically investigated. Modal properties and gain competition between Fundamental Mode (FM) and first HOM have been calculated, in presence of thermal effects. The main doped fiber characteristics have been derived by comparison between experimental and numerical results.

  12. Thermal-Responsive Polymers for Enhancing Safety of Electrochemical Storage Devices.

    Science.gov (United States)

    Yang, Hui; Leow, Wan Ru; Chen, Xiaodong

    2018-03-01

    Thermal runway constitutes the most pressing safety issue in lithium-ion batteries and supercapacitors of large-scale and high-power density due to risks of fire or explosion. However, traditional strategies for averting thermal runaway do not enable the charging-discharging rate to change according to temperature or the original performance to resume when the device is cooled to room temperature. To efficiently control thermal runaway, thermal-responsive polymers provide a feasible and reversible strategy due to their ability to sense and subsequently act according to a predetermined sequence when triggered by heat. Herein, recent research progress on the use of thermal-responsive polymers to enhance the thermal safety of electrochemical storage devices is reviewed. First, a brief discussion is provided on the methods of preventing thermal runaway in electrochemical storage devices. Subsequently, a short review is provided on the different types of thermal-responsive polymers that can efficiently avoid thermal runaway, such as phase change polymers, polymers with sol-gel transitions, and polymers with positive temperature coefficients. The results represent the important development of thermal-responsive polymers toward the prevention of thermal runaway in next-generation smart electrochemical storage devices. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Filamentary and diffuse barrier discharges

    International Nuclear Information System (INIS)

    Kogelschatz, U.

    2001-01-01

    Barrier discharges, sometimes also referred to as dielectric-barrier discharges or silent discharges, are characterized by the presence of at least one insulating layer in contact with the discharge between two planar or cylindrical electrodes connected to an ac power supply. The main advantage of this type of electrical discharge is, that non-equilibrium plasma conditions in atmospheric-pressure gases can be established in an economic and reliable way. This has led to a number of important applications including industrial ozone generation, surface modification of polymers, plasma chemical vapor deposition, excitation of CO 2 lasers, excimer lamps and, most recently, large-area flat plasma display panels. Depending on the application, the width of the discharge gap can range from less than 0.1 mm to about 100 mm and the applied frequency from below line frequency to several gigahertz. Typical materials used for the insulating layer (dielectric barrier) are glass, quartz, ceramics but also thin enamel or polymer layers

  14. All solid state pulsed power system for water discharge

    OpenAIRE

    Sakugawa, Takashi; Yamaguchi, Takahiro; Yamamoto, Kunihiro; Kiyan, Tsuyoshi; Namihira, Takao; Katsuki, Sunao; Akiyama, Hidenori; サクガワ, タカシ; ヤマグチ, タカヒロ; ヤマモト, クニヒロ; キヤン, ツヨシ; ナミヒラ, タカオ; カツキ, スナオ; アキヤマ, ヒデノリ; 佐久川, 貴志

    2005-01-01

    Pulsed power has been used to produce non-thermal plasmas in gases that generate a high electric field at the tip of streamer discharges, where high energy electrons, free radicals, and ozone are produced. Recently, all solid state pulsed power generators, which are operated with high repetition rate, long lifetime and high reliability, have been developed for industrial applications, such as high repetition rate pulsed gas lasers, high energy density plasma (EUV sources) and water discharges...

  15. Charging and discharging tests for obtaining an accurate dynamic electro-thermal model of high power lithium-ion pack system for hybrid and EV applications

    DEFF Research Database (Denmark)

    Mihet-Popa, Lucian; Camacho, Oscar Mauricio Forero; Nørgård, Per Bromand

    2013-01-01

    This paper presents a battery test platform including two Li-ion battery designed for hybrid and EV applications, and charging/discharging tests under different operating conditions carried out for developing an accurate dynamic electro-thermal model of a high power Li-ion battery pack system....... The aim of the tests has been to study the impact of the battery degradation and to find out the dynamic characteristics of the cells including nonlinear open circuit voltage, series resistance and parallel transient circuit at different charge/discharge currents and cell temperature. An equivalent...... circuit model, based on the runtime battery model and the Thevenin circuit model, with parameters obtained from the tests and depending on SOC, current and temperature has been implemented in MATLAB/Simulink and Power Factory. A good alignment between simulations and measurements has been found....

  16. Eco-friendly preparation of large-sized graphene via short-circuit discharge of lithium primary battery.

    Science.gov (United States)

    Kang, Shaohong; Yu, Tao; Liu, Tingting; Guan, Shiyou

    2018-02-15

    We proposed a large-sized graphene preparation method by short-circuit discharge of the lithium-graphite primary battery for the first time. LiC x is obtained through lithium ions intercalation into graphite cathode in the above primary battery. Graphene was acquired by chemical reaction between LiC x and stripper agents with dispersion under sonication conditions. The gained graphene is characterized by Raman spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Atomic force microscope (AFM) and Scanning electron microscopy (SEM). The results indicate that the as-prepared graphene has a large size and few defects, and it is monolayer or less than three layers. The quality of graphene is significant improved compared to the reported electrochemical methods. The yield of graphene can reach 8.76% when the ratio of the H 2 O and NMP is 3:7. This method provides a potential solution for the recycling of waste lithium ion batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Treatment of mixed wastes by thermal plasma discharges

    International Nuclear Information System (INIS)

    Diaz A, L.V.

    2007-01-01

    The present study has as purpose to apply the technology of thermal plasma in the destruction of certain type of waste generated in the ININ. As first instance, origin, classification and disposition of the radioactive waste generated in the ININ is identified. Once identified the waste, the waste to treat is determined based on: the easiness of treating him with plasma, classification and importance. Later on, a substance or compound settles down (sample model) that serves as indicative of the waste for its physical-chemical characteristics, this is made because in the Thermal Plasma Applications Laboratory is not had the license to work with radioactive material. The sample model and the material to form the vitreous matrix are characterized before and after the treatment in order to evaluating their degradation and vitrification. During the treatment by means of the thermal plasma, the appropriate conditions are determined for the degradation and vitrification of the waste. Also, it is carried out an energy balance in the system to know the capacity to fuse the material depending the transfer of existent heat between the plasma and the material to treat. Obtaining favorable results, it thought about to climb in the project and by this way to help to solve one of the environmental problems in Mexico, as they are it the mixed wastes. (Author)

  18. Electrochemical performance of Si-multiwall carbon nanotube nanocomposite anode synthesized by thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Na, Ye-Seul; Yoo, Hyeonseok; Kim, Tae-Hee; Choi, Jinsub; Lee, Wan In; Choi, Sooseok, E-mail: sooseok@jejunu.ac.kr; Park, Dong-Wha, E-mail: dwpark@inha.ac.kr

    2015-07-31

    Lithium-ion (Li-ion) batteries are widely used in electric devices and vehicles. Silicon is a promising material for the anode of Li-ion battery due to high theoretical specific capacity. However, it shows large volume changes during charge–discharge cycles leading to the pulverization of electrode. In order to improve such disadvantage, a multiwall carbon nanotube (MWCNT) has been used with silicon as composite material. In this work, Si-MWCNT nanocomposite was prepared in thermal plasma by attaching silicon nanoparticles to MWCNT column. Electrochemical tests for raw materials and synthesized nanocomposites were carried out. The discharge capacities of silicon, MWCNT, synthesized nanocomposites collected from a reaction tube, and a chamber were 4000, 310, 200, and 1447 mAh/g, respectively. - Highlights: • Si-Multiwall carbon nanotube nanocomposite was synthesized by thermal plasma. • The effect on the collection position of product after experiment was examined. • Cycle performance of electrodes was measured. • Product collected from chamber showed good electrochemical performance.

  19. Anomalously temperature-dependent thermal conductivity of monolayer GaN with large deviations from the traditional 1 /T law

    Science.gov (United States)

    Qin, Guangzhao; Qin, Zhenzhen; Wang, Huimin; Hu, Ming

    2017-05-01

    Efficient heat dissipation, which is featured by high thermal conductivity, is one of the crucial issues for the reliability and stability of nanodevices. However, due to the generally fast 1 /T decrease of thermal conductivity with temperature increase, the efficiency of heat dissipation quickly drops down at an elevated temperature caused by the increase of work load in electronic devices. To this end, pursuing semiconductor materials that possess large thermal conductivity at high temperature, i.e., slower decrease of thermal conductivity with temperature increase than the traditional κ ˜1 /T relation, is extremely important to the development of disruptive nanoelectronics. Recently, monolayer gallium nitride (GaN) with a planar honeycomb structure emerges as a promising new two-dimensional material with great potential for applications in nano- and optoelectronics. Here, we report that, despite the commonly established 1 /T relation of thermal conductivity in plenty of materials, monolayer GaN exhibits anomalous behavior that the thermal conductivity almost decreases linearly over a wide temperature range above 300 K, deviating largely from the traditional κ ˜1 /T law. The thermal conductivity at high temperature is much larger than the expected thermal conductivity that follows the general κ ˜1 /T trend, which would be beneficial for applications of monolayer GaN in nano- and optoelectronics in terms of efficient heat dissipation. We perform detailed analysis on the mechanisms underlying the anomalously temperature-dependent thermal conductivity of monolayer GaN in the framework of Boltzmann transport theory and further get insight from the view of electronic structure. Beyond that, we also propose two required conditions for materials that would exhibit similar anomalous temperature dependence of thermal conductivity: large difference in atom mass (huge phonon band gap) and electronegativity (LO-TO splitting due to strong polarization of bond). Our

  20. Plasma characteristics of long-pulse discharges heated by neutral beam injection in the Large Helical Device

    Science.gov (United States)

    Takeiri, Y.; Nakamura, Y.; Noda, N.; Osakabe, M.; Kawahata, K.; Oka, Y.; Kaneko, O.; Tsumori, K.; Sato, M.; Mutoh, T.; Shimozuma, T.; Goto, M.; Ida, K.; Inagaki, S.; Kado, S.; Masuzaki, S.; Morita, S.; Nagayama, Y.; Narihara, K.; Peterson, B. J.; Sakakibara, S.; Sato, K.; Shoji, M.; Tanaka, K.; de Vries, P. C.; Sudo, S.; Ohyabu, N.; Motojima, O.

    2000-02-01

    Long-pulse neutral beam injection heating has been achieved in the large helical device (LHD). Two different confinement states are observed for different averaged densities in the long-pulse plasmas. A quasi-steady-state plasma was sustained for 21 s with an injection power of 0.6 MW, where the central plasma temperature was around 1 keV with a line-averaged electron density of 0.3 × 1019 m-3 . The discharge duration can be so extended as to keep the plasma properties in the short-pulse discharge. The energy confinement time is nearly the same as that of the short-pulse discharge, which is 1.3 times as long as the international stellarator scaling ISS95. At higher densities, a relaxation oscillation phenomenon, observed as if the plasma would breathe, lasted for 20 s with a period of 1-2 s. The phenomenon is characterized with profile expansion and contraction of the electron temperature. The density oscillation is out of phase with the temperature oscillation and is related to the density clamping phenomenon. The observed plasma properties are shown in detail for the `breathing' oscillation phenomenon. Possible mechanisms for the breathing oscillation are also discussed, with a view of the screening effect near the last closed magnetic surface and the power balance between the heating and the radiation powers. The long-pulse heating results indicate unique characteristics of the LHD where no special feedback stabilization is required due to absence of disruption and no need for current drive.

  1. Thermal performance of a PCM thermal storage unit

    Energy Technology Data Exchange (ETDEWEB)

    Liu Ming; Bruno, Frank; Saman, Wasim [Sustainable Energy Centre, Inst. for Sustainable Systems and Technologies, Univ. of South Australia, Mawson Lakes, Adelaide (Australia)

    2008-07-01

    The thermal performance of a PCM thermal storage unit (TSU) is studied numerically and experimentally. The TSU under analysis consists of several flat slabs of phase change material (PCM) with melting temperature of -26.7 C. Liquid heat transfer fluid (HTF) passes between the slabs to charge and discharge the storage unit. A one dimensional mathematical model was employed to analyze the transient thermal behavior of the storage unit during the melting and freezing processes. The model takes into consideration the temperature variations in the wall along the flow direction of the HTF. The paper compares the experimental and numerical simulation results in terms of HTF outlet temperatures during the melting period. (orig.)

  2. Vehicle exhaust treatment using electrical discharge and materials chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Tonkyn, R.G.; Balmer, M.L.; Barlow, S.E.; Orlando, T.M. [Pacific Northwest National Lab., Richland, WA (United States); Goulette, D.; Hoard, J. [Ford Motor Co., Dearborn, MI (United States). Scientific Research Lab.

    1997-12-31

    Current 3-way catalytic converters have proven quite effective at removing NO{sub x} from the exhaust of spark ignition vehicles operating near stoichiometric air-to-fuel ratios. However, diesel engines typically operate at very high air-to-fuel ratios. Under such lean burn conditions current catalytic converters are ineffective for NO{sub x} removal. As a result, considerable effort has been made to develop a viable lean NO{sub x} catalyst. Although some materials have been shown to reduce NO{sub x} under lean burn conditions, none exhibit the necessary activity and stability at the high temperatures and humidities found in typical engine exhaust,. As a result, alternative technologies are being explored in an effort to solve the so-called lean NO{sub x} problem. Packed-bed barrier discharge systems are well suited to take advantage of plasma-surface interactions due to the large number of contaminant surface collisions in the bed. The close proximity of the active surface to transient species produced by the plasma may lead to favorable chemistry at considerably lower temperatures than required by thermal catalysts. The authors present data in this paper illustrating that the identity and surface properties of the packing material can alter the discharge-driven chemistry in synthetic leanburn exhaust mixtures. Results using non-porous glass beads as the packing material suggest the limits of NO{sub x} reduction using purely gas phase discharge chemistry. By comparison, encouraging results are reported for several alternative packing materials.

  3. Process Performances of 2 ns Pulsed Discharge Plasma

    Science.gov (United States)

    Matsumoto, Takao; Wang, Douyan; Namihira, Takao; Akiyama, Hidenori

    2011-08-01

    Pulsed discharge plasmas have been used to treat exhaust gases. Since pulse duration and the rise time of applied voltage to the discharge electrode has a strong influence on the energy efficiency of pollutant removal, the development of a short-pulse generator is of paramount importance for practical applications. In this work, it is demonstrated that the non thermal plasma produced by the 2 ns pulsed discharge has a higher energy efficiency than the 5 ns pulsed discharge plasma for NO removal and ozone generation. Typically, the NO removal efficiency was 1.0 mol kW-1 h-1 for 70% NO removal (initial NO concentration = 200 ppm, gas flow = 10 L/min). Meanwhile, the ozone yield was 500 g kW-1 h-1 for 20 g/m3 ozone concentration in the case of oxygen feeding. These energy efficiencies are the highest in the literature.

  4. Analysis of mobile ionic impurities in polyvinylalcohol thin films by thermal discharge current and dielectric impedance spectroscopy

    Directory of Open Access Journals (Sweden)

    M. Egginger

    2012-12-01

    Full Text Available Polyvinylalcohol (PVA is a water soluble polymer frequently applied in the field of organic electronics for insulating thin film layers. By-products of PVA synthesis are sodium acetate ions which contaminate the polymer material and can impinge on the electronic performance when applied as interlayer dielectrics in thin film transistors. Uncontrollable voltage instabilities and unwanted hysteresis effects are regularly reported with PVA devices. An understanding of these effects require knowledge about the electronic dynamics of the ionic impurities and their influence on the dielectric properties of PVA. Respective data, which are largely unknown, are being presented in this work. Experimental investigations were performed from room temperature to 125°C on drop-cast PVA films of three different quality grades. Data from thermal discharge current (TDC measurements, polarization experiments, and dielectric impedance spectroscopy concurrently show evidence of mobile ionic carriers. Results from TDC measurements indicate the existence of an intrinsic, build-in electric field of pristine PVA films. The field is caused by asymmetric ionic double layer formation at the two different film-interfaces (substrate/PVA and PVA/air. The mobile ions cause strong electrode polarization effects which dominate dielectric impedance spectra. From a quantitative electrode polarization analysis of isothermal impedance spectra temperature dependent values for the concentration, the mobility and conductivity together with characteristic relaxation times of the mobile carriers are given. Also shown are temperature dependent results for the dc-permittivity and the electronic resistivity. The obtained results demonstrate the feasibility to partly remove contaminants from a PVA solution by dialysis cleaning. Such a cleaning procedure reduces the values of ion concentration, conductivity and relaxation frequency.

  5. Large eddy simulation on thermal fluid mixing in a T-junction piping system

    Energy Technology Data Exchange (ETDEWEB)

    Selvam, P. Karthick; Kulenovic, R.; Laurien, E. [Stuttgart Univ. (Germany). Inst fuer Kernenergie und Energiesysteme (IKE)

    2014-11-15

    High cycle thermal fatigue damage caused in piping systems is an important problem encountered in the context of nuclear safety and lifetime management of a Nuclear Power Plant (NPP). The T-junction piping system present in the Residual Heat Removal System (RHRS) is more vulnerable to thermal fatigue cracking. In this numerical study, thermal mixing of fluids at temperature difference (?T) of 117 K between the mixing fluids is analyzed. Large Eddy Simulation (LES) is performed with conjugate heat transfer between the fluid and structure. LES is performed based on the Fluid-Structure Interaction (FSI) test facility at University of Stuttgart. The results show an intense turbulent mixing of fluids downstream of T-junction. Amplitude of temperature fluctuations near the wall region and its corresponding frequency distribution is analyzed. LES is performed using commercial CFD software ANSYS CFX 14.0.

  6. Experimental investigation on the thermal performance of heat pipe-assisted phase change material based battery thermal management system

    International Nuclear Information System (INIS)

    Wu, Weixiong; Yang, Xiaoqing; Zhang, Guoqing; Chen, Kai; Wang, Shuangfeng

    2017-01-01

    Highlights: • A heat pipe assisted phase change material based battery thermal management system is proposed. • The proposed system is compact and efficient from a view of practical application. • Cycling conditions are experimentally simulated for practical working environment. • The proposed system presents better thermal performance in comparison to other systems. • Combining forced air convection with heat pipe further enhances the cooling effect. - Abstract: In this paper, a heat pipe-assisted phase change material (PCM) based battery thermal management (BTM) system is designed to fulfill the comprehensive energy utilization for electric vehicles and hybrid electric vehicles. Combining the large heat storage capacity of the PCM with the excellent cooling effect of heat pipe, the as-constructed heat pipe-assisted PCM based BTM is feasible and effective with a relatively longer operation time and more suitable temperature. The experimental results show that the temperature maldistribution of battery module can be influenced by heat pipes when they are activated under high discharge rates of the batteries. Moreover, with forced air convection, the highest temperature could be controlled below 50 °C even under the highest discharge rate of 5C and a more stable and lower temperature fluctuation is obtained under cycling conditions. Meanwhile, the effectiveness of further increasing air velocity (i.e., more fan power consumption) is limited when the highest temperature continues to reduce at a lower rate due to the phase transition process of PCM. These results are expected to provide insights into the design and optimization of BTM systems.

  7. Mathematical modelling of thermal-plume interaction at Waterford Nuclear Power Station

    International Nuclear Information System (INIS)

    Tsai, S.Y.H.

    1981-01-01

    The Waldrop plume model was used to analyze the mixing and interaction of thermal effluents in the Mississippi River resulting from heated-water discharges from the Waterford Nuclear Power Station Unit 3 and from two nearby fossil-fueled power stations. The computer program of the model was modified and expanded to accommodate the multiple intake and discharge boundary conditions at the Waterford site. Numerical results of thermal-plume temperatures for individual and combined operation of the three power stations were obtained for typical low river flow (200,000 cfs) and maximum station operating conditions. The predicted temperature distributions indicated that the surface jet discharge from Waterford Unit 3 would interact with the thermal plumes produced by the two fossil-fueled stations. The results also showed that heat recirculation between the discharge of an upstream fossil-fueled plant and the intake of Waterford Unit 3 is to be expected. However, the resulting combined temperature distributions were found to be well within the thermal standards established by the state of Louisiana

  8. Surface modification of steels by electrical discharge treatment in electrolyte

    International Nuclear Information System (INIS)

    Krastev, D.; Paunov, V.; Yordanov, B.; Lazarova, V.

    2013-01-01

    Full text: In this work are discussed some experimental data about the influence of applied electrical discharge treatment in electrolyte on the surface structure of steels. The electrical discharge treatment of steel surface in electrolyte gives a modified structure with specific combination of characteristics in result of nonequilibrium transformations. The modification goes by a high energy thermal process in a very small volume on the metallic surface involving melting, vaporisation, activation and alloying in electrical discharges, and after that cooling of this surface with high rate in the electrolyte. The surface layers obtain a different structure in comparison with the metal matrix and are with higher hardness, wear resistance and corrosion resistance. key words: surface modification, electrical discharge treatment in electrolyte, steels

  9. Comparative studies of high-frequency and direct current molecular gas discharges

    International Nuclear Information System (INIS)

    Goichman, V.H.; Goldfarb, V.M.; Tendler, M.B.

    1975-01-01

    Electron gas parameters, gas temperatures, ionization and thermal instability are found to be markedly different in direct current glow discharges from capactive electrodless high frequency discharge even when equal net power input is provided. It is reasonable to expect that the combined discharge containing both types of discharges mentioned above may be expected to improve significantly both the steady-state and transient characteristics of the plasma. The characteristics of different discharges in air, nitrogen air-CO 2 -He mixture have been compared. Because of the lack of the direct electrical methods for measurements of the hf plasma, exphasis in this investigation has been laid on both theoretical) based on the analytical expression for electron energy distribution function received previously and experimental spectroscopic evaluations of the plasma parameters. (Auth.)

  10. The discharges from Sellafield how big a risk for the Irish population?

    Energy Technology Data Exchange (ETDEWEB)

    O` Flaherty, T [Radiological Protection Inst. of Ireland (Ireland)

    1996-10-01

    The site operated by British Nuclear Fuels Ltd (BNFL) at Sellafield in Cumbria was established just after World War II to produce plutonium for the manufacture of nuclear weapons. Plutonium was obtained by extracting it from nuclear fuel which had been irradiated in an early type of nuclear reactor. This procedure was the forerunner of what ultimately became the main commercial activity at Sellafield, the reprocessing of spent nuclear fuel to recover re-usable uranium and plutonium An unavoidable consequence of nuclear fuel reprocessing is the necessity to discharge from the site very large volumes of low-level radioactive waste in liquid form. In the case of Sellafield this waste is discharged into the Irish Sea. Due to a plant malfunction the rates of discharge greatly increased in the mid-1970s, and became a matter of serious concern to the people of Ireland and to successive Irish Governments. In more recent years the rates of discharge have fallen again to lower levels, but this has not diminished concern in Ireland to any significant degree. This paper summarises the results of Irish monitoring of radioactivity levels in the Irish Sea which has been in progress since the late 1970s. From these results it quantifies the radiation doses received by people in Ireland in consequence of the discharges from Sellafield, and estimates the degree of risk of increased cancer levels in the Irish population as a result. The RPII`s monitoring programme has been expanded since 1993 in the light of the bringing into operation of the new Thermal Oxide Reprocessing Plant (Thorp) and now includes the monitoring of gaseous discharges to the atmosphere. The paper includes some initial results of this expanded programme.

  11. Large scale solar thermal power for the European Union{exclamation_point}

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1997-06-01

    Southern Europe, on the edge of the sunbelt, represents the ideal location for solar thermal generated power. Last year. SAWIE reported on the THESEUS project, a proposed 50 MWe solar thermal power plant for Frangokastello, southern Crete, which was submitted for support under the European Union`s THERMIE Programme. Funding was approved for the design phase for this innovative power plant, the first large-scale SEGS-style plant on European soil, at the end of last year. However, the THERMIE Programme also provided support for another Southern European plant, proposed by Colon Solar for Huelva in Southern Spain. Whilst hurdles remain to be overcome before both plants are built and commissioned, there is an excellent chance that by the start of the new Millennium, the solar collectors from these two plants could be generating over half a million MWh of energy a year. SAWIE compares the two projects. (author)

  12. Numerical investigation of dielectric barrier discharges

    Science.gov (United States)

    Li, Jing

    1997-12-01

    A dielectric barrier discharge (DBD) is a transient discharge occurring between two electrodes in coaxial or planar arrangements separated by one or two layers of dielectric material. The charge accumulated on the dielectric barrier generates a field in a direction opposite to the applied field. The discharge is quenched before an arc is formed. It is one of the few non-thermal discharges that operates at atmospheric pressure and has the potential for use in pollution control. In this work, a numerical model of the dielectric barrier discharge is developed, along with the numerical approach. Adaptive grids based on the charge distribution is used. A self-consistent method is used to solve for the electric field and charge densities. The Successive Overrelaxation (SOR) method in a non-uniform grid spacing is used to solve the Poisson's equation in the cylindrically-symmetric coordinate. The Flux Corrected Transport (FCT) method is modified to solve the continuity equations in the non-uniform grid spacing. Parametric studies of dielectric barrier discharges are conducted. General characteristics of dielectric barrier discharges in both anode-directed and cathode-directed streamer are studied. Effects of the dielectric capacitance, the applied field, the resistance in external circuit and the type of gases (O2, air, N2) are investigated. We conclude that the SOR method in an adaptive grid spacing for the solution of the Poisson's equation in the cylindrically-symmetric coordinate is convergent and effective. The dielectric capacitance has little effect on the g-factor of radical production, but it determines the strength of the dielectric barrier discharge. The applied field and the type of gases used have a significant role on the current peak, current pulse duration and radical generation efficiency, discharge strength, and microstreamer radius, whereas the external series resistance has very little effect on the streamer properties. The results are helpful in

  13. COMMENTS ON THE SEARCH FOR ELECTROSTATIC DISCHARGES ON MARS

    International Nuclear Information System (INIS)

    Renno, Nilton O.; Ruf, Christopher S.

    2012-01-01

    Ruf et al. used the Deep Space Network (DSN) to search for the emission of non-thermal radiation by martian dust storms, theoretically predicted by Renno et al. They detected the emission of non-thermal radiation that they were searching for, but were surprised that it contained spectral peaks suggesting modulation at various frequencies and their harmonics. Ruf et al. hypothesized that the emission of non-thermal radiation was caused by electric discharges in a deep convective dust storm, modulated by Schumann resonances (SRs). Anderson et al. used the Allen Telescope Array (ATA) to search for similar emissions. They stated that they found only radio frequency interference (RFI) during their search for non-thermal emission by martian dust storms and implicitly suggested that the signal detected by Ruf et al. was also RFI. However, their search was not conducted during the dust storm season when deep convective storms are most likely to occur. Here, we show that the ubiquitous dust devils and small-scale dust storms that were instead likely present during their observations are too shallow to excite SRs and produce the signals detected by Ruf et al. We also show that the spectral and temporal behavior of the signals detected by Anderson et al. corroborates the idea that they originated from man-made pulse-modulated telecommunication signals rather than martian electric discharges. In contrast, an identical presentation of the signals detected by Ruf et al. demonstrates that they do not resemble man-made signals. The presentation indicates that the DSN signals were consistent with modulation by martian SRs, as originally hypothesized by Ruf et al. We propose that a more comprehensive search for electrostatic discharges be conducted with either the ATA or DSN during a future martian dust storm season to test the hypothesis proposed by Ruf et al.

  14. Capacitor Discharge - A Capacitor Tutorial [video

    OpenAIRE

    Naval Postgraduate School Physics

    2014-01-01

    NPS Physics Physics Demonstrations Here's a capacitor discharge demonstrated by physicist Dr. Dernardo. Dr. D gives a nice capacitor lesson along with some fireworks. Charging and Discharging a Capacitor is dangerous. Do not try this at home. Dr. Bruce Denardo uses eleven 9V batteries, connected in series for a total of 99 creating a pretty large spark.

  15. Pending laboratory tests and the hospital discharge summary in patients discharged to sub-acute care.

    Science.gov (United States)

    Walz, Stacy E; Smith, Maureen; Cox, Elizabeth; Sattin, Justin; Kind, Amy J H

    2011-04-01

    Previous studies have noted a high (41%) prevalence and poor discharge summary communication of pending laboratory (lab) tests at the time of hospital discharge for general medical patients. However, the prevalence and communication of pending labs within a high-risk population, specifically those patients discharged to sub-acute care (i.e., skilled nursing, rehabilitation, long-term care), remains unknown. To determine the prevalence and nature of lab tests pending at hospital discharge and their inclusion within hospital discharge summaries, for common sub-acute care populations. Retrospective cohort study. Stroke, hip fracture, and cancer patients discharged from a single large academic medical center to sub-acute care, 2003-2005 (N = 564) Pending lab tests were abstracted from the laboratory information system (LIS) and from each patient's discharge summary, then grouped into 14 categories and compared. Microbiology tests were sub-divided by culture type and number of days pending prior to discharge. Of sub-acute care patients, 32% (181/564) were discharged with pending lab tests per the LIS; however, only 11% (20/181) of discharge summaries documented these. Patients most often left the hospital with pending microbiology tests (83% [150/181]), particularly blood and urine cultures, and reference lab tests (17% [30/181]). However, 82% (61/74) of patients' pending urine cultures did not have 24-hour preliminary results, and 19% (13/70) of patients' pending blood cultures did not have 48-hour preliminary results available at the time of hospital discharge. Approximately one-third of the sub-acute care patients in this study had labs pending at discharge, but few were documented within hospital discharge summaries. Even after considering the availability of preliminary microbiology results, these omissions remain common. Future studies should focus on improving the communication of pending lab tests at discharge and evaluating the impact that this improved

  16. Rotating thermal convection at very large Rayleigh numbers

    Science.gov (United States)

    Weiss, Stephan; van Gils, Dennis; Ahlers, Guenter; Bodenschatz, Eberhard

    2016-11-01

    The large scale thermal convection systems in geo- and astrophysics are usually influenced by Coriolis forces caused by the rotation of their celestial bodies. To better understand the influence of rotation on the convective flow field and the heat transport at these conditions, we study Rayleigh-Bénard convection, using pressurized sulfur hexaflouride (SF6) at up to 19 bars in a cylinder of diameter D=1.12 m and a height of L=2.24 m. The gas is heated from below and cooled from above and the convection cell sits on a rotating table inside a large pressure vessel (the "Uboot of Göttingen"). With this setup Rayleigh numbers of up to Ra =1015 can be reached, while Ekman numbers as low as Ek =10-8 are possible. The Prandtl number in these experiment is kept constant at Pr = 0 . 8 . We report on heat flux measurements (expressed by the Nusselt number Nu) as well as measurements from more than 150 temperature probes inside the flow. We thank the Deutsche Forschungsgemeinschaft (DFG) for financial support through SFB963: "Astrophysical Flow Instabilities and Turbulence". The work of GA was supported in part by the US National Science Foundation through Grant DMR11-58514.

  17. Current scaling for the radiative characteristics of a micropinch discharge

    International Nuclear Information System (INIS)

    Dogov, A.N.

    2005-01-01

    The absolute vacuum UV and soft X-ray (hν > 100 eV) yield from a micropinch discharge of plasma is measured. The current scaling in the range of 30-250 kA is found for a number of the discharge parameters: the vacuum UV and soft X-ray yield, electron temperature, effective temperature of suprathermal electrons and energy of bremsstrahlung emission from thermal electrons. The experimental data are in a good agreement with the calculated data [ru

  18. Thermal applications of low-pressure diamond

    International Nuclear Information System (INIS)

    Haubner, R.; Lux, B.

    1997-01-01

    During the last decade several applications of low-pressure diamond were developed. Main products are diamond heat-spreaders using its high thermal conductivity, diamond windows with their high transparency over a wide range of wavelengths and wear resistant tool coatings because of diamonds superhardness. A short description of the most efficient diamond deposition methods (microwave, DC-glow discharge, plasma-jet and arc discharge) is given. The production and applications of diamond layers with high thermal conductivity will be described. Problems of reproducibility of diamond deposition, the influence of impurities, the heat conductivity in electronic packages, reliability and economical mass production will be discussed. (author)

  19. Fabrication of epoxy composites with large-pore sized mesoporous silica and investigation of their thermal expansion.

    Science.gov (United States)

    Suzuki, Norihiro; Kiba, Shosuke; Yamauchi, Yusuke

    2012-02-01

    We fabricate epoxy composites with low thermal expansion by using mesoporous silica particles with a large pore diameter (around 10 nm) as inorganic fillers. From a simple calculation, almost all the mesopores are estimated to be completely filled with the epoxy polymer. The coefficient of linear thermal expansion (CTE) values of the obtained epoxy composites proportionally decrease with the increase of the mesoporous silica content.

  20. Surface treatment of polyethylene terephthalate film using atmospheric pressure glow discharge in air

    International Nuclear Information System (INIS)

    Fang Zhi; Qiu Yuchang; Wang Hui

    2004-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in polymer surface processing because of their convenience, effectiveness and low cost. In this paper, the treatment of Polyethylene terephthalate (PET) film surface for improving hydrophilicity using the non-thermal plasma generated by atmospheric pressure glow discharge (APGD) in air is conducted. The discharge characteristics of APGD are shown by measurement of their electrical discharge parameters and observation of light-emission phenomena, and the surface properties of PET before and after the APGD treatment are studied using contact angle measurement, x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It is found that the APGD is homogeneous and stable in the whole gas gap, which differs from the commonly filamentary dielectric barrier discharge (DBD). A short time (several seconds) APGD treatment can modify the surface characteristics of PET film markedly and uniformly. After 10 s APGD treatment, the surface oxygen content of PET surface increases to 39%, and the water contact angle decreases to 19 degree, respectively. (authors)

  1. European research school on large scale solar thermal – SHINE

    DEFF Research Database (Denmark)

    Bales, Chris; Forteza, Pau Joan Cortés; Furbo, Simon

    2014-01-01

    The Solar Heat Integration NEtwork (SHINE) is a European research school in which 13 PhD students in solar thermal technologies are funded by the EU Marie-Curie program. It has five PhD course modules as well as workshops and seminars dedicated to PhD students both within the project as well...... as outside of it. The SHINE research activities focus on large solar heating systems and new applications: on district heating, industrial processes and new storage systems. The scope of this paper is on systems for district heating for which there are five PhD students, three at universities and two...

  2. Disruption characteristics in PDX with limiter and divertor discharges

    International Nuclear Information System (INIS)

    Couture, P.; McGuire, K.

    1986-09-01

    A comparison has been made between the characteristics of disruptions with limiter and divertor configurations in PDX. A large data base on disruptions has been collected over four years of machine operation, and a total of 15,000 discharges are contained in the data file. It was found that divertor discharges have less disruptions during ramp up and flattop of the plasma current. However, for divertor discharges a large number of fast, low current disruptions take place during the current ramp down. These disruptions are probably caused by the deformation of the plasma shape

  3. Physical and engineering aspects of thermal pollution

    International Nuclear Information System (INIS)

    Parker, F.L.; Krenkel, P.A.

    1970-01-01

    The problems of the thermal pollution of our water ways by central electricity generating stations are discussed under the following headings: physical, biological, and chemical effects on water quality; effects of heated discharges on waste assimilation; beneficial effects of heat additions; prediction of heat dissipation; mechanism of heated water discharges; modeling of heated discharges; cooling ponds and run of the river cooling; cooling towers; cooling tower problems; and comparison of cooling methods

  4. Corrugated paraffin nanocomposite films as large stroke thermal actuators and self-activating thermal interfaces.

    Science.gov (United States)

    Copic, Davor; Hart, A John

    2015-04-22

    High performance active materials are of rapidly growing interest for applications including soft robotics, microfluidic systems, and morphing composites. In particular, paraffin wax has been used to actuate miniature pumps, solenoid valves, and composite fibers, yet its deployment is typically limited by the need for external volume constraint. We demonstrate that compact, high-performance paraffin actuators can be made by confining paraffin within vertically aligned carbon nanotube (CNT) films. This large-stroke vertical actuation is enabled by strong capillary interaction between paraffin and CNTs and by engineering the CNT morphology by mechanical compression before capillary-driven infiltration of the molten paraffin. The maximum actuation strain of the corrugated CNT-paraffin films (∼0.02-0.2) is comparable to natural muscle, yet the maximum stress is limited to ∼10 kPa by collapse of the CNT network. We also show how a CNT-paraffin film can serve as a self-activating thermal interface that closes a gap when it is heated. These new CNT-paraffin film actuators could be produced by large-area CNT growth, infiltration, and lamination methods, and are attractive for use in miniature systems due to their self-contained design.

  5. Thermal neutron self-shielding correction factors for large sample instrumental neutron activation analysis using the MCNP code

    International Nuclear Information System (INIS)

    Tzika, F.; Stamatelatos, I.E.

    2004-01-01

    Thermal neutron self-shielding within large samples was studied using the Monte Carlo neutron transport code MCNP. The code enabled a three-dimensional modeling of the actual source and geometry configuration including reactor core, graphite pile and sample. Neutron flux self-shielding correction factors derived for a set of materials of interest for large sample neutron activation analysis are presented and evaluated. Simulations were experimentally verified by measurements performed using activation foils. The results of this study can be applied in order to determine neutron self-shielding factors of unknown samples from the thermal neutron fluxes measured at the surface of the sample

  6. Growth and male reproduction improvement of non-thermal dielectric barrier discharge plasma treatment on chickens

    Science.gov (United States)

    Jiao Zhang, Jiao; Luong Huynh, Do; Chandimali, Nisansala; Kang, Tae Yoon; Kim, Nameun; Mok, Young Sun; Kwon, Taeho; Jeong, Dong Kee

    2018-05-01

    This study investigated whether plasma treatment of fertilized eggs before hatching could affect the growth and reproduction of chickens. Three point five-day-incubated fertilized eggs exposed to non-thermal dielectric barrier discharge plasma at 2.81 W of power for 2 min resulted in the highest growth in chickens. Plasma growth-promoting effect was regulated by the reactive oxygen species homeostasis and the improvement of energy metabolism via increasing serum hormones and adenosine triphosphate levels which were resulted from the regulation of genes involved in antioxidant defense, hormone biosynthesis and energetic metabolism. Interestingly, plasma-treated male chickens conspicuously grew faster than females. Further, aspects of male reproductive system (testosterone level and sperm quality) were improved by the plasma treatment but female reproduction (estradiol and progesterone levels, egg-laying rate and egg weight) had no significant changes. Unfortunately, offspring whose parents were the optimal plasma-treated chickens did not show any difference on growth characteristics and failed to inherit excellent growth features from their parents. Our results suggest a new method to improve the growth rate and male reproductive capacity in poultry but it is only effective in the plasma direct-treated generation.

  7. Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation

    Science.gov (United States)

    Madureira, Joana; Ceriani, Elisa; Pinhão, Nuno; Marotta, Ester; Melo, Rita; Cabo Verde, Sandra; Paradisi, Cristina; Margaça, Fernanda M. A.

    2017-11-01

    In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a $^{60}$Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO$_2$ was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments.

  8. Charging and discharging characteristics of cool thermal energy storage system with horizontal pipes using water as phase change material

    International Nuclear Information System (INIS)

    Sait, H.H.; Selim, A.M.

    2014-01-01

    Highlights: • Ice is formed around horizontal tubes. • Optimum solid ice releasing is found. • Freezing and releasing of ice are controlled by ice resistance, time and tubes spacing. - Abstract: An experimental investigation of ice formation on cold vertical banks of horizontal tubes subjected to falling-film– jet mode– is conducted. In the charging process, a set of internally cooled vertical banks of horizontal tubes of brine is subjected to a falling film of water. The formed ice is periodically observed, photographed and measured in falling-film jet mode at specific internal coolant (ethylene–glycol solution) flow rates and temperatures. In the discharge process, the same solution is heated and used internally to release ice. Different thicknesses of the released ice are observed and measured. The maximum quantity of released ice is obtained and the optimum ice formation is determined. The results indicate that the ice formation and the solid ice released are controlled by the thermal resistance of the ice, time and pitch between tubes. The maximum gained ice has a thickness that is approximately equal to half of the tube spacing between the tubes utilized, which is formed in approximately 45 min and released in 12.5 min. The variation in heating solution temperature has a slight effect on the gained ice and discharging time

  9. Characterization of a dielectric barrier discharge in controlled atmosphere

    Science.gov (United States)

    Kogelheide, Friederike; Offerhaus, Björn; Bibinov, Nikita; Bracht, Vera; Smith, Ryan; Lackmann, Jan-Wilm; Awakowicz, Peter; Stapelmann, Katharina; Bimap Team; Aept Team

    2016-09-01

    Non-thermal atmospheric-pressure plasmas are advantageous for various biomedical applications as they make a contact- and painless therapy possible. Due to the potential medical relevance of such plasma sources further understanding of the chemical and physical impact on biological tissue regarding the efficacy and health-promoting effect is necessary. The knowledge of properties and effects offers the possibility to configure plasmas free of risk for humans. Therefore, tailoring the discharge chemistry in regard to resulting oxidative and nitrosative effects on biological tissue by adjusting different parameters is of growing interest. In order to ensure stable conditions for the characterization of the discharge, the used dielectric barrier discharge was mounted in a vessel. Absolutely calibrated optical emission spectroscopy was carried out to analyze the electron density and the reduced electric field. The rather oxygen-based discharge was tuned towards a more nitrogen-based discharge by adjusting several parameters as reactive nitrogen species are known to promote wound healing. Furthermore, the impact of an ozone-free discharge has to be studied. This work was funded by the German Research Foundation (DFG) with the packet grant PAK 816 `Plasma Cell Interaction in Dermatology'.

  10. To a question on thermal protection of constructional elements of vacuum-plasma devices

    International Nuclear Information System (INIS)

    Borisko, V.N.; Borisko, S.V.; Zinovev, D.V.; Lapshin, V.I.; Tselujko, A.F.

    2005-01-01

    The progress in development of vacuum-plasma devices is connected with the design and creation of constructional elements from materials, which have a high erosion resistance and can maintain the large specific flux of energy per effective area. Recently as the materials of such constructional elements it was offered to use the reversible sorbents of hydrogen of Zr-V system, which have high-rates of sorption-desorption and large thermal effect of the hydride phases decomposition. In the paper an experimental research of the thermal conditions features of the metal-hydride electrodes, which subjected of the energy loads in the vacuum-plasma devices, are given. The simulation of the energy loads on the electrodes was carried out with the help of gas discharge plasma as there is an possibility to vary the energy spectrum of the bombarding particles and to gather a necessary radiation dose to the material surface. For comparative examinations of various materials under the irradiation by high-energy heavy particles it is the most convenient to use the Penning discharge. In this case, the cathodes made of different materials are under the identical conditions even at the change of working discharge modes. Therefore in the device on the basis of the Penning discharge the cathodes of metal-hydride and stainless steel were set. It was detected, that the increase of the temperature gradient of metal-hydride cathode goes down with the increase of discharge current value. The dependence of operating temperatures difference of cathodes from exposure time has shown that the temperature of the metal-hydride cathode is sufficiently lower than the temperature of the stainless steel cathode. Such a softening of the thermal operation conditions of the metal hydride cathode is caused by thermal decomposition of hydride phases. Besides there is the energy flow dissipation of bombarding particles on the protective gas target formed by desorbed hydrogen. The considerable decrease of

  11. Numerical Simulation of a Nanosecond-Pulse Discharge for High-Speed Flow Control

    Science.gov (United States)

    Poggie, Jonathan; Adamovich, Igor

    2012-10-01

    Numerical calculations were carried out to examine the physics of the operation of a nanosecond-pulse, single dielectric barrier discharge in a configuration with planar symmetry. This simplified configuration was chosen as a vehicle to develop a physics based nanosecond discharge model, including realistic air plasma chemistry and compressible bulk gas flow. First, a reduced plasma kinetic model was developed by carrying out a sensitivity analysis of zero-dimensional plasma computations with an extended chemical kinetic model. Transient, one- dimensional discharge computations were then carried out using the reduced kinetic model, incorporating a drift-diffusion formulation for each species, a self-consistent computation of the electric potential using the Poisson equation, and a mass-averaged gas dynamic formulation for the bulk gas motion. Discharge parameters (temperature, pressure, and input waveform) were selected to be representative of recent experiments on bow shock control with a nanosecond discharge in a Mach 5 cylinder flow. The computational results qualitatively reproduce many of the features observed in the experiments, including the rapid thermalization of the input electrical energy and the consequent formation of a weak shock wave. At breakdown, input electrical energy is rapidly transformed (over roughly 1 ns) into ionization products, dissociation products, and electronically excited particles, with subsequent thermalization over a relatively longer time-scale (roughly 10 μs).

  12. Two discharge modes of a repetitive nanosecond pulsed helium glow discharge under sub-atmospheric pressure in the repetition frequency range of 20 to 600 kHz

    Science.gov (United States)

    Kikuchi, Yusuke; Maegawa, Takuya; Otsubo, Akira; Nishimura, Yoshimi; Nagata, Masayoshi; Yatsuzuka, Mitsuyasu

    2018-05-01

    Two discharge modes, α and γ, of a repetitive nanosecond pulsed helium glow discharge at a gas pressure of 10 kPa in the repetition frequency range from 20 to 600 kHz are reported for the first time. The pulsed glow discharge is produced in a pair of parallel plate metal electrodes without insertion of dielectrics. The α mode discharge is volumetrically produced in the electrode gap at a low-repetition frequency, whereas the γ mode discharge is localized at the cathode surface at a high-repetition frequency. At high-repetition frequency, the time interval between voltage pulses is shorter than the lifetime of the afterglow produced by the preceding discharge. Then, the γ mode discharge is maintained by a large number of secondary electrons emitted from the cathode exposed to high-density ions and metastable helium atoms in the afterglow. In the α mode discharge with a low-repetition frequency operation, primary electrons due to gas ionization dominate the ionization process. Thus, a large discharge voltage is needed for the excitation of the α mode discharge. It is established that the bifurcation of α-γ discharge mode, accompanied by a decrease in the discharge voltage, occurs at the high-repetition frequency of ∼120 kHz.

  13. An overview of technology and research in electrode design and manufacturing in sinking electrical discharge machining

    Directory of Open Access Journals (Sweden)

    Bhola Jha

    2014-06-01

    Full Text Available Electrical discharge machining (EDM is one of the earliest non-traditional machining processes, based on thermoelectric energy between the workpiece and an electrode. In this process, the material is removed electro thermally by a series of successive discrete discharges between two electrically conductive objects, i.e., the electrode and the workpiece. The performance of the process, to a large extent, depends on the material, design and manufacturing method of the electrodes. Electrode design and method of its manufacturing also affect on the cost of electrode. Researchers have explored a number of ways to improve electrode design and devised various ways of manufacturing. The paper reports a review on the research relating to EDM electrode design and its manufacturing for improving and optimizing performance measures and reducing time and cost of manufacturing. The final part of the paper discusses these developments and outlines the trends for future research work.

  14. Numerical study on lithium titanate battery thermal response under adiabatic condition

    International Nuclear Information System (INIS)

    Sun, Qiujuan; Wang, Qingsong; Zhao, Xuejuan; Sun, Jinhua; Lin, Zijing

    2015-01-01

    Highlights: • The thermal behavior of lithium titanate battery during cycling was investigated. • The temperature rate in charging was less than that of discharging in the cycling. • The temperature difference was less than 0.02 °C at 0.5 C in adiabatic condition. • The temperature distribution and thermal runaway of the battery were predicted. - Abstract: To analyze the thermal behavior of 945 mA h lithium titanate battery during charging and discharging processes, the experimental and numerical studies are performed in this work. The cathode and anode of the 945 mA h lithium titanate soft package battery are the lithium nickel–cobalt–manganese-oxide and lithium titanate, respectively. In the experiment, an Accelerating Rate Calorimeter combined with battery cycler is employed to investigate the electrochemical–thermal behavior during charge–discharge cycling under the adiabatic condition. In numerical simulation, one electrochemical-thermal model is adopted to predict the thermal response and validated with the experimental results. From both experimental and simulated results, the profile of potential and current, the heat generation, the temperature, the temperature changing rate and the temperature distribution in the cell are obtained and thermal runaway is predicted. The analysis of the electrochemical and thermal behavior is beneficial for the commercial application of lithium titanate battery in the fields of electric vehicles and hybrid electric vehicles

  15. Electrical probe measurements in low and high pressure discharges

    International Nuclear Information System (INIS)

    Andersson, D.

    1976-11-01

    The construction of an apparatus for automatic determination of electron distributions is described, whereafter measurements of electron energy distributions before and after a stationary plasma sheath in a low pressure mercury discharge are presented. The sheath appears at a constriction of the discharge tube. The measurements have been made with a spheric probe, using the second-derivative method, and the results show that the energy distribution on the anode side of the sheath is a sum of a thermal population and an accelerated distribution. Near the sheath the accelerated electrons suffice to carry the discharge current, but far from it the current must be carried by an anisotropy in the thermal part of the distribution function. A comparison is made with calculated distributions. The cross-sections for electron-neutral and Coulomb collisions are not sufficient to account for the damping of the accelerated population, suggesting the presence of a plasma instability. In order to study the distribution function of the axial velocity component, preliminary measurements of the first derivative of the current to a plane probe have been made. Such measurements yield information about the anisotropy and the current transport, and may perhaps shed some light on the phenomenon of current limitation. Some measurements on a TIG welding arc are also described. (Auth.)

  16. Electron runaway in rf discharges

    International Nuclear Information System (INIS)

    Chen, F.F.

    1992-10-01

    The critical electric field is computed as a function of pressure and starting energy for electrons to run away to high energies in moderate pressure discharges. The runaway conditions depend critically on the shape of the elastic cross section vs. energy curve. Computations are made for H, H 2 , and He gases, and it is shown that runaway occurs much more readily in atomic hydrogen than in the other gases. The values of the runaway fields are larger than would normally occur in dc discharges, where large voltages would lead to arc formation. However, in rf discharges such electric fields can be sustained over times long compared to electron transit times but short compared to ion transit times. (author)

  17. Large displacement spring-like electro-mechanical thermal actuators with insulator constraint beams

    Science.gov (United States)

    Luo, J. K.; Fu, Y. Q.; Flewitt, A. J.; Spearing, S. M.; Fleck, N. A.; Milne, W. I.

    2005-07-01

    A number of in-plane spring-like micro-electro-thermal-actuators with large displacements were proposed. The devices take the advantage of the large difference in the thermal expansion coefficients between the conductive arms and the insulator clamping beams. The constraint beams in one type (the spring) of these devices are horizontally positioned to restrict the expansion of the active arms in the x-direction, and to produce a displacement in the y-direction only. In other two types of actuators (the deflector and the contractor), the constraint beams are positioned parallel to the active arms. When the constraint beams are on the inside of the active arms, the actuator produces an outward deflection in the y-direction. When they are on the outside of the active arms, the actuator produces an inward contraction. Analytical model and finite element analysis were used to simulate the performances. It showed that at a constant temperature, analytical model is sufficient to predict the displacement of these devices. The displacements are all proportional to the temperature and the number of the chevron sections. A two-mask process is under development to fabricate these devices, using Si3N4 as the insulator beams, and electroplated Ni as the conductive beams.

  18. Thermography During Thermal Test of the Gaia Deployable Sunshield Assembly Qualification Model in the ESTEC Large Space Simulator

    Science.gov (United States)

    Simpson, R.; Broussely, M.; Edwards, G.; Robinson, D.; Cozzani, A.; Casarosa, G.

    2012-07-01

    The National Physical Laboratory (NPL) and The European Space Research and Technology Centre (ESTEC) have performed for the first time successful surface temperature measurements using infrared thermal imaging in the ESTEC Large Space Simulator (LSS) under vacuum and with the Sun Simulator (SUSI) switched on during thermal qualification tests of the GAIA Deployable Sunshield Assembly (DSA). The thermal imager temperature measurements, with radiosity model corrections, show good agreement with thermocouple readings on well characterised regions of the spacecraft. In addition, the thermal imaging measurements identified potentially misleading thermocouple temperature readings and provided qualitative real-time observations of the thermal and spatial evolution of surface structure changes and heat dissipation during hot test loadings, which may yield additional thermal and physical measurement information through further research.

  19. Technological challenges in thermal plasma production

    International Nuclear Information System (INIS)

    Ramakrishnan, S.

    1995-01-01

    Thermal plasmas, generated by electric arc discharges, are used in a variety of industrial applications. The electric arc is a constricted electrical discharge with a high temperature in the range 6000-25,000 K. These characteristics are useful in plasma cutting, spraying, welding and specific areas of material processing. The thermal plasma technology is an enabling process technology and its status in the market depends upon its advantages over competing technologies. A few technological challenges to enhance the status of plasma technology are to improve the utilisation of the unique characteristics of the electric arc and to provide enhanced control of the process. In particular, new solutions are required for increasing the plasma-material interaction, controlling the electrode roots and controlling the thermal power generated by the arcing process. In this paper, the advantages of plasma technology, its constraints and future challenges for technology developments are highlighted. 36 refs., 14 figs

  20. The Forsmark biotest basin. An instrument for environmental research. Experiences of large cooling water discharges in Sweden (1969-1993) and research perspectives for the future

    International Nuclear Information System (INIS)

    Snoeijs, P.

    1994-01-01

    This report presents the Biotest basin at Forsmark (Sweden) as an instrument for experimental environmental research, and indicates possibilities for its future use. the basin consists of a 1 km 2 artificial enclosure in the Baltic Sea that receives cooling water discharge from the Forsmark nuclear power plant. Cooling water discharge was initiated in 1980, and since then the basin has been serving as the main Swedish instrument for field studies on the effects of enhanced temperature and low-dose radioactivity on aquatic ecosystems. Environmental effects of large cooling water discharges from power plants to the sea have been studied at other sites in Sweden too, and for the sake of completeness of background information this report provides a survey and an extensive bibliography of all previous research on cooling water discharges in Sweden during the last 25 years. The aim of scientific research in the Biotest basin is to provide an independent academically-based assessment of the effects of the discharges of heat to the aquatic environment and of the pathways of pollutants through the ecosystems. Until now the research has mainly been describing the ecological effects of the cooling water flow through the basin under normal operation of the power plant. In the future it will be possible to manipulate the basin for large field experiments. An important perspective for the future is that of climatic change; the Forsmark Biotest basin provides excellent conditions for field studies on possible biological effects. This includes e.g. temperature effects on basic biological processes (growth, metabolism, reproduction etc.), population genetics, and combination effects of heat and toxic substances. 60 refs, 3 figs, 6 tabs

  1. Physics of mercury-free high-pressure discharge lamps

    International Nuclear Information System (INIS)

    Born, M

    2002-01-01

    This paper gives a summary of recent results about the replacement of mercury in high-pressure discharge lamps by metallic zinc. Actually, this topic is of high relevance for the lighting industry due to the need of more environmentally friendly products. The work presented here is supported by the German government under contract no 13N8072 and 13N8264. Due to upcoming European legislations which are expected for the year 2003, the replacement of mercury in lighting products is a high priority task. For example, mercury-free headlight discharge lamps are requested by the automotive industry. Pure zinc/argon discharges as well as lamps including zinc or mercury and metal halide additives are investigated. Experimental data are compared with model calculations of the energy balance involving the transport of heat and radiation. Since the excitation energies of relevant zinc transitions are lower than for mercury, axis temperatures of pure zinc lamps are about 300 K below the value of mercury arcs. In addition, the thermal conductivity of zinc including the contribution of radiation diffusion is larger than compared to mercury. From lamp voltage measurements it is found that the cross section for elastical electron scattering by zinc atoms is about the same than for mercury. When adding metal halides to a pure zinc discharge with argon as a starting gas, i.e. NaI, TlI, DyI 3 , axis temperatures decrease to about 5100 K due to strong radiation cooling. In order to obtain sufficiently large lamp voltages, wall temperatures of more than 1300 K are adjusted by means of polycrystalline aluminaoxide (Al 2 O 3 ) as a wall material. Electric field strengths of 6.0 and 8.6 V mm -1 are measured for metal halide lamps containing zinc or mercury, respectively. The light technical data of the discharges are very close, since mercury and zinc do not contribute significantly to the radiation in the visible range. Efficacies of up to 93 and 100 lm W -1 are found in metal halide

  2. Discharge Characteristics of DC Arc Water Plasma for Environmental Applications

    Science.gov (United States)

    Li, Tianming; Sooseok, Choi; Takayuki, Watanabe

    2012-12-01

    A water plasma was generated by DC arc discharge with a hafnium embedded rod-type cathode and a nozzle-type anode. The discharge characteristics were examined by changing the operation parameter of the arc current. The dynamic behavior of the arc discharge led to significant fluctuations in the arc voltage and its frequency. Analyses of the high speed image and the arc voltage waveform showed that the arc discharge was in the restrike mode and its frequency varied within several tens of kilohertz according to the operating conditions. The larger thermal plasma volume was generated by the higher flow from the forming steam with a higher restrike frequency in the higher arc current conditions. In addition, the characteristics of the water plasma jet were investigated by means of optical emission spectroscopy to identify the abundant radicals required in an efficient waste treatment process.

  3. Cooling problems of thermal power plants. Physical model studies

    International Nuclear Information System (INIS)

    Neale, L.C.

    1975-01-01

    The Alden Research Laboratories of Worcester Polytechnic Institute has for many years conducted physical model studies, which are normally classified as river or structural hydraulic studies. Since 1952 one aspect of these studies has involved the heated discharge from steam power plants. The early studies on such problems concentrated on improving the thermal efficiency of the system. This was accomplished by minimizing recirculation and by assuring full use of available cold water supplies. With the growing awareness of the impact of thermal power generation on the environment attention has been redirected to reducing the effect of heated discharges on the biology of the receiving body of water. More specifically the efforts of designers and operators of power plants are aimed at meeting or complying with standards established by various governmental agencies. Thus the studies involve developing means of minimizing surface temperatures at an outfall or establishing a local area of higher temperature with limits specified in terms of areas or distances. The physical models used for these studies have varied widely in scope, size, and operating features. These models have covered large areas with both distorted geometric scales and uniform dimensions. Instrumentations has also varied from simple mercury thermometers to computer control and processing of hundreds of thermocouple indicators

  4. Free double layers in mercury-arc discharges

    International Nuclear Information System (INIS)

    Maciel, H.S.; Allen, J.E.

    1989-01-01

    A study has been carried out of free double layers formed within the plasma volume of a low-pressure mercury-arc discharge at high current densities. The free double layer is observed to form as a visible boundary, which drifts slowly from the central section of the discharge. Current-driven instabilities are observed as the discharge current is gradually increased to a critical value, at which current limitation is observed to occur. This process, which is accompanied by high-current spikes, ceases when the free double layer becomes visible as a sharp boundary dividing the discharge column into two regions of different luminosities. The layer is observed to form in the later stages of current limitation, the onset of which occurs for a ratio of drift to thermal speed of electrons of about unity. Electrical energy is converted by the layer into kinetic energy of the changed particles. Accordingly high-energy ions were measured by means of an electrostatic energy analyser. The multiple-sheath character of the free 'double layer'', which is inferred from probe measurements of potential profiles, is discussed and comparisons with other space-charge structures with the same topology are made. (author)

  5. Angina - discharge

    Science.gov (United States)

    Chest pain - discharge; Stable angina - discharge; Chronic angina - discharge; Variant angina - discharge; Angina pectoris - discharge; Accelerating angina - discharge; New-onset angina - discharge; Angina-unstable - discharge; ...

  6. Current-Induced Membrane Discharge

    DEFF Research Database (Denmark)

    Andersen, Mathias Bækbo; van Soestbergen, M.; Mani, A.

    2012-01-01

    . Salt depletion leads to a large electric field resulting in a local pH shift within the membrane with the effect that the membrane discharges and loses its ion selectivity. Since salt co-ions, H+ ions, and OH- ions contribute to OLC, CIMD interferes with electrodialysis (salt counterion removal...... neglects chemical effects and remains to be quantitatively tested. Here, we show that charge regulation and water self-ionization can lead to OLC by "current-induced membrane discharge'' (CIMD), even in the absence of fluid flow, in ion-exchange membranes much thicker than the local Debye screening length...

  7. Partitioning Hydrologic and Biological Drivers of Discharge Loss in Arctic Headwater Streams

    Science.gov (United States)

    Koch, J. C.; Carey, M.; O'Donnell, J. A.; Records, M. K.; Sjoberg, Y.; Zimmerman, C. E.

    2017-12-01

    The Arctic-Boreal transition (ABT) zone of Alaska is experiencing unprecedented warming, leading to permafrost thaw and vegetation change. Both of these processes are likely to affect streams and stream ecosystems, but there is little direct empirical evidence regarding the magnitude of these effects and their relative importance. To understand how permafrost thaw and vegetation are affecting streams at the ABT, we monitored 8 first-order streams that drain catchments varying in elevation, aspect, and vegetation cover. Data were obtained from meteorological stations, continuous stream discharge, seepage runs, and stream tracer experiments. Hydrograph analysis indicated that runoff ratios in south-facing catchments were lower than north-facing catchments and decreased over the season. Seepage runs indicated that south-facing catchments lost a large portion of water (up to 50% per km stream reach) in the late summer, while north-facing catchments were gaining water. All streams displayed diel variability in discharge, but with different daily and seasonal trends related to aspect and elevation. South-facing, forested catchment streams showed diel discharge timing consistent with cycles in evapotranspiration rates, while the signal in north-facing catchments and those dominated by tundra was more consistent with thermal controls on water viscosity and groundwater discharge to streams. Together, these signals indicate that the warmer, south-facing catchments are losing a large portion of water to a combination of infiltration and evapotranspiration. The seasonal trends are consistent with higher infiltration rates beneath south-facing streams as the ground thaws over the summer. The magnitude and seasonal dynamics of the diel signatures help separate biological (i.e. evapotranspiration) vs. physical controls (i.e. frozen ground hydrology) on stream-catchment interactions, which vary depending on aspect, elevation, and vegetation cover. Warming, and subsequent increases

  8. Vapor Discharges On Nevado Del Ruiz During The Recent Activity: Clues On The Composition Of The Deep Hydrothermal System And Its Effects On Thermal Springs

    Science.gov (United States)

    Inguaggiato, S.; Federico, C.; Chacon, Z.; Londono, J. M.; Alzate, D. M.; Gil, E.

    2015-12-01

    The Nevado del ruiz volcano (NdR, 5321m asl), one of the most active in Colombia, threatens about 600,000 people. The existence of an ice cap and several streams channeling in some main rivers increase the risk of lahars and mudflows in case of unrest, as occurred during the November 1985 eruption, which caused 20,000 casualties. The involvement of the local hydrothermal system has also produced in the past phreatic and phreatomagmatic activity, as in 1985 and 1989. After more than 7 years of relative stability, since 2010, the still ongoing phase of unrest has produced two small eruption in 2012, and still maintains in high levels of seismicity and SO2 degassing. In October 2013, a sampling campaign has been performed on thermal springs and streamwater, located at 2600-5000 m asl, analyzed for water chemistry and stable isotopes. By applying a model of steam-heating, based on mass and enthalpy balances, we have estimated the mass rate of steam discharging in the different steam-heated springs. The composition of the hottest thermal spring (Botero Londoño) is probably representative of a marginal part of the hydrothermal system, having a temperature of 250°C and low salinity (Cl ~1500 mg/l), which suggest a chiefly meteoric origin, as also confirmed by the isotope composition retrieved for the hydrothermal water. The vapour discharged at the steam vent "Nereidas" (3600 m asl) is hypothesised to be separated from a high-temperature hyrothermal system. Based on its composition and on literature data on fluid inclusions, we have retrieved the P-T-X conditions of the deep hydrothermal system, as well as its pH and fO2. The vapour feeding Nereidas would separate from a byphasic hydrothermal system characterised by the follow parameters: t= 315°C, P=19 MPa, NaCl= 15 %, CO2 = 9%, and similar proportion between liquid and vapour. Considering also the equilibria involving S-bearing gases and HCl, we obtain pH=2, fO2 fixed by FeO-Fe2O3 buffer, and [Cl]=12000 mg/l. Changes

  9. Thermal performance of solar air collection-storage system with phase change material based on flat micro-heat pipe arrays

    International Nuclear Information System (INIS)

    Wang, Teng-yue; Diao, Yan-hua; Zhu, Ting-ting; Zhao, Yao-hua; Liu, Jing; Wei, Xiang-qian

    2017-01-01

    Highlights: • A new type of solar air collection-storage thermal system with PCM is proposed. • Flat micro-heat pipe array is used as the core heat transfer element. • Air volume flow rate influence charging and discharging time obviously. • Air-side thermal resistance dominates during charging and discharging. - Abstract: In this study, a new type of solar air collection-storage thermal system (ACSTS) with phase change material (PCM) is designed using flat micro-heat pipe arrays (FMHPA) as the heat transfer core element. The solar air collector comprises FMHPA and vacuum tubes. The latent thermal storage device (LTSD) utilizes lauric acid, which is a type of fatty acid, as PCM. The experiments test the performance of collector efficiency and charging and discharging time of thermal storage device through different air volume flow rates. After a range of tests, high air volume flow rate is concluded to contribute to high collector efficiency and short charging and discharging time and enhance instantaneous heat transfer, whereas an air volume flow rate of 60 m"3/h during discharging provides a steady outlet temperature. The cumulative heat transfer during discharging is between 4210 and 4300 kJ.

  10. The use of large area silicon sensors for thermal neutron detection

    International Nuclear Information System (INIS)

    Schulte, R.L.; Swanson, F.; Kesselman, M.

    1994-01-01

    The use of large area planar silicon detectors coupled with gadolinium foils has been investigated to develop a thermal neutron detector having a large area-efficiency (Aε) product. Noise levels due to high detector capacitance limit the size of silicon detectors that can be utilized. Calculations using the Monte Carlo code, MCNP, have been made to determine the variation of intrinsic detection efficiency as a function of the discriminator threshold level required to eliminate the detector noise. Measurements of the noise levels for planar silicon detectors of various resistivities (400, 3000 and 5000 Ω cm) have been made and the optimal detector area-efficiency products have been determined. The response of a Si-Gd-Si sandwich detector with areas between 1 cm 2 and 10.5 cm 2 is presented and the effects of the detector capacitance and reverse current are discussed. ((orig.))

  11. Electronic perturbation investigations into excitation and ionization in the millisecond pulsed glow discharge plasma

    International Nuclear Information System (INIS)

    Li Lei; Robertson-Honecker, Jennifer; Vaghela, Vishal; King, Fred L.

    2006-01-01

    This study employed a power perturbation method to examine the energy transfer processes at different locations within the afterpeak regime of a millisecond pulsed glow discharge plasma. Brief power perturbation pulses were applied during the afterpeak regime altering the environment of the collapsing plasma. Responses of several transitions to the power perturbations were measured via atomic emission and absorption spectroscopic methods at various distances from the surface of the cathode. The experimental data provide further insight into the energy transfer processes that occur at different spatial locations and in different temporal regimes of these pulsed glow discharge plasmas. Although the enhancement of the large population of metastable argon atoms is again confirmed, the mechanism responsible for this enhancement remains unclear. The most likely possibility involves some form of ion-electron recombination followed by radiative relaxation of the resulting species. The metastable argon atoms subsequently Penning ionize sputtered copper atoms which then appear to undergo a similar ion-electron recombination process yielding variable degrees of observable afterpeak emission for copper atom transitions. The kinetic information of these processes was approximated from the corresponding relaxation time. The electron thermalization time allowing for recombination with ions was found to be ∼25 μs after the discharge power termination

  12. Development of electric discharge equipment for small specimen sampling

    International Nuclear Information System (INIS)

    Okamoto, Koji; Kitagawa, Hideaki; Kusumoto, Junichi; Kanaya, Akihiro; Kobayashi, Toshimi

    2009-01-01

    We have developed the on-site electric discharge sampling equipment that can effectively take samples such as small specimens from the surface portion of the plant components. Compared with the conventional sampling equipment, our sampling equipment can take samples that are thinner in depth and larger in area. In addition, the affection to the equipment can be held down to the minimum, and the thermally-affected zone of the material due to electric discharge is small, which is to be ignored. Therefore, our equipment is excellent in taking samples for various tests such as residual life evaluation.

  13. Formation and Thermal Stability of Large Precipitates and Oxides in Titanium and Niobium Microalloyed Steel

    Institute of Scientific and Technical Information of China (English)

    ZHUO Xiao-jun; WOO Dae-hee; WANG Xin-hua; LEE Hae-geon

    2008-01-01

    As-cast CC slabs of microalloyed steels are prone to surface and sub-surface cracking. Precipitation phenomena in-itiated during solidification reduce ductility at high temperature. The unidirectional solidification unit is employed to sim-ulate the solidification process during continuous casting. Precipitation behavior and thermal stability are systemati-cally investigated. Samples of adding titanium and niobium to steels have been examined using field emission scanning electron microscope (FE-SEM), electron probe X-ray microanalyzer (EPMA), and transmission electron microscope (TEM). It has been found that the addition of titanium and niobium to high-strength low-alloyed (HSLA) steel resuited in undesirable large precipitation in the steels, i. e. , precipitation of large precipitates with various morphologies. The composition of the large precipitates has been determined. The effect of cooling rate on (Ti, Nb)(C, N) precipitate formation is investigated. With increasing the cooling rate, titanium-rich (Ti,Nb)(C, N) precipitates are transformed to niobium-rich (Ti,Nb)(C,N) precipitates. The thermal stability of these large precipitates and oxides have been assessed by carrying out various heat treatments such as holding and quenching from temperature at 800 and 1 200 ℃. It has been found that titanium-rich (Ti,Nb)(C,N) precipitate is stable at about 1 200 ℃ and niobi-um-rich (Ti,Nb)(C,N) precipitate is stable at about 800 ℃. After reheating at 1 200 ℃ for 1 h, (Ca, Mn)S and TiN are precipitated from Ca-Al oxide. However, during reheating at 800 ℃ for 1 h, Ca-Al-Ti oxide in specimens was stable. The thermodynamic calculation of simulating the thermal process is employed. The calculation results are in good agreement with the experimental results.

  14. Subsurface thermal behaviour of tissue mimics embedded with large blood vessels during plasmonic photo-thermal therapy.

    Science.gov (United States)

    Paul, Anup; Narasimhan, Arunn; Das, Sarit K; Sengupta, Soujit; Pradeep, Thalappil

    2016-11-01

    The purpose of this study was to understand the subsurface thermal behaviour of a tissue phantom embedded with large blood vessels (LBVs) when exposed to near-infrared (NIR) radiation. The effect of the addition of nanoparticles to irradiated tissue on the thermal sink behaviour of LBVs was also studied. Experiments were performed on a tissue phantom embedded with a simulated blood vessel of 2.2 mm outer diameter (OD)/1.6 mm inner diameter (ID) with a blood flow rate of 10 mL/min. Type I collagen from bovine tendon and agar gel were used as tissue. Two different nanoparticles, gold mesoflowers (AuMS) and graphene nanostructures, were synthesised and characterised. Energy equations incorporating a laser source term based on multiple scattering theories were solved using finite element-based commercial software. The rise in temperature upon NIR irradiation was seen to vary according to the position of the blood vessel and presence of nanoparticles. While the maximum rise in temperature was about 10 °C for bare tissue, it was 19 °C for tissue embedded with gold nanostructures and 38 °C for graphene-embedded tissues. The axial temperature distribution predicted by computational simulation matched the experimental observations. A different subsurface temperature distribution has been obtained for different tissue vascular network models. The position of LBVs must be known in order to achieve optimal tissue necrosis. The simulation described here helps in predicting subsurface temperature distributions within tissues during plasmonic photo-thermal therapy so that the risks of damage and complications associated with in vivo experiments and therapy may be avoided.

  15. Electric-discharge-pumped nitrogen ion laser

    Science.gov (United States)

    Laudenslager, J. B.; Pacala, T. J.; Wittig, C.

    1976-01-01

    The routine operation is described of an N2(+) laser oscillating on the first negative band system of N2(+) which is produced in a preionized transverse discharge device. The discharge design incorporates features which favor the efficient production of the excitation transfer reaction of He2(+) with N2. A capacitive discharge switched by means of a high-current grounded grid thyratron is used to meet the design requirement of a volumetric discharge in high-pressure gas mixtures where the electric discharge need not have an ultrafast rise time (greater than 10 nsec) but should be capable of transferring large quantities of stored electric energy to the gas. A peak power of 180 kW in an 8-nsec laser pulse was obtained with a 0.1% mixture of N2 in helium at a total pressure of 3 atm. The most intense laser oscillations were observed on the (0,1) vibrational transition at 427.8 microns.

  16. Pulsed electrical discharge in gas bubbles in water

    Science.gov (United States)

    Gershman, Sophia

    A phenomenological picture of pulsed electrical discharge in gas bubbles in water is produced by combining electrical, spectroscopic, and imaging methods. The discharge is generated by applying one microsecond long 5 to 20 kilovolt pulses between the needle and disk electrodes submerged in water. A gas bubble is generated at the tip of the needle electrode. The study includes detailed experimental investigation of the discharge in argon bubbles and a brief look at the discharge in oxygen bubbles. Imaging, electrical characteristics, and time-resolved optical emission data point to a fast streamer propagation mechanism and formation of a plasma channel in the bubble. Spectroscopic methods based on line intensity ratios and Boltzmann plots of line intensities of argon, atomic hydrogen, and argon ions and the examination of molecular emission bands from molecular nitrogen and hydroxyl radicals provide evidence of both fast beam-like electrons and slow thermalized ones with temperatures of 0.6 -- 0.8 electron-volts. The collisional nature of plasma at atmospheric pressure affects the decay rates of optical emission. Spectroscopic study of rotational-vibrational bands of hydroxyl radical and molecular nitrogen gives vibrational and rotational excitation temperatures of the discharge of about 0.9 and 0.1 electron-volt, respectively. Imaging and electrical evidence show that discharge charge is deposited on the bubble wall and water serves as a dielectric barrier for the field strength and time scales of this experiment. Comparing the electrical and imaging information for consecutive pulses applied at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from long-lived chemical species, such as ozone and oxygen. Intermediate values for the discharge gap and pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique

  17. 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.

  18. Discharge Characteristics of DC Arc Water Plasma for Environmental Applications

    International Nuclear Information System (INIS)

    Choi, Sooseok; Watanabe, Takayuki; Li Tianming

    2012-01-01

    A water plasma was generated by DC arc discharge with a hafnium embedded rod-type cathode and a nozzle-type anode. The discharge characteristics were examined by changing the operation parameter of the arc current. The dynamic behavior of the arc discharge led to significant fluctuations in the arc voltage and its frequency. Analyses of the high speed image and the arc voltage waveform showed that the arc discharge was in the restrike mode and its frequency varied within several tens of kilohertz according to the operating conditions. The larger thermal plasma volume was generated by the higher flow from the forming steam with a higher restrike frequency in the higher arc current conditions. In addition, the characteristics of the water plasma jet were investigated by means of optical emission spectroscopy to identify the abundant radicals required in an efficient waste treatment process. (plasma technology)

  19. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    International Nuclear Information System (INIS)

    Moreno, H.; Pacheco, M.; Mercado, A.; Cruz, A.; Pacheco, J.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-01-01

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma

  20. Investigation of slide-away discharges in the HT-7 tokamak

    International Nuclear Information System (INIS)

    Lu Hongwei; Hu Liqun; Lin Shiyao; Zhong Guoqian; Zhou Ruijie

    2010-01-01

    In tokamak plasmas, the discharge will go into 'runaway' discharges if the density decays to the critical ones. The discharge will go into 'slide-away' discharges if the density reaches a lower level. The slide-away discharge is characterized by high confinement and lots of superthermal electrons which constitute a large part of plasma current. In HT-7 Tokamak, the slide-away discharges have been achieved by decreasing the plasma density. The relation ship between plasma current and the critical density of slide-away discharge was investigated. It was also found that the increase of density in slide-away discharge can make the confinement poor. And also, lots of superthermal electrons lost from the vacuum chamber. (authors)

  1. Thermal Analysis of the Advanced Technology Large Aperture Space Telescope (ATLAST) 8 Meter Primary Mirror

    Science.gov (United States)

    Hornsby, Linda; Stahl, H. Philip; Hopkins, Randall C.

    2010-01-01

    The Advanced Technology Large Aperture Space Telescope (ATLAST) preliminary design concept consists of an 8 meter diameter monolithic primary mirror enclosed in an insulated, optical tube with stray light baffles and a sunshade. ATLAST will be placed in orbit about the Sun-Earth L2 and will experience constant exposure to the sun. The insulation on the optical tube and sunshade serve to cold bias the telescope which helps to minimize thermal gradients. The primary mirror will be maintained at 280K with an active thermal control system. The geometric model of the primary mirror, optical tube, sun baffles, and sunshade was developed using Thermal Desktop(R) SINDA/FLUINT(R) was used for the thermal analysis and the radiation environment was analyzed using RADCAD(R). A XX node model was executed in order to characterize the static performance and thermal stability of the mirror during maneuvers. This is important because long exposure observations, such as extra-solar terrestrial planet finding and characterization, require a very stable observatory wave front. Steady state thermal analyses served to predict mirror temperatures for several different sun angles. Transient analyses were performed in order to predict thermal time constant of the primary mirror for a 20 degree slew or 30 degree roll maneuver. This paper describes the thermal model and provides details of the geometry, thermo-optical properties, and the environment which influences the thermal performance. All assumptions that were used in the analysis are also documented. Parametric analyses are summarized for design parameters including primary mirror coatings and sunshade configuration. Estimates of mirror heater power requirements are reported. The thermal model demonstrates results for the primary mirror heated from the back side and edges using a heater system with multiple independently controlled zones.

  2. Multi-step capacitor discharges as an RF generator

    International Nuclear Information System (INIS)

    Hotta, Eiki; Yamamoto, Shunji; Ishii, Shozo; Hayashi, Izumi

    1979-01-01

    A variety of methods have been developed for large output radio frequency (RF) generators to heat and stabilize high temperature plasma. As the generators for this purpose, capacitor discharge, cable discharge, and oscillation with electronic tubes are considered. Here, a new RF generator is reported, which utilizes capacitor discharge to extract heavy current, and solves the difficulty of short duration by employing multistep discharges. The authors solved the problem of frequency decrease in capacitor discharge by cutting off the unnecessary capacitors reasonably from the load circuit, using the additional circuit for shunting current and vacuum gap switches. The vacuum gap switches and the trigger system are described together with the RF generator manufactured. The generator was fabricated to be rather compact for its large output and simple in circuitry as compared with conventional oscillator systems. The shortcomings are frequency variation and the improper phase of switching the next step in to cause instability, when the load change occurs. It would be difficult to operate the generator in a RF range of more than about 10 MHz due to jitter of the vacuum gap switches and others. (Wakatsuki, Y.)

  3. Comparison of experimentally-inferred ion thermal diffusivities with neoclassical theory for neutral beam-heated discharges in the Doublet III tokamak

    International Nuclear Information System (INIS)

    Groebner, R.J.

    1986-04-01

    The study of ion transport in neutral beam-heated discharges in tokamaks is necessary to determine if neoclassical theory can reliably be used to predict the performance of future machines. Previous studies of ion tranport have generally been difficult due to the lack of information regarding the ion temperature profile. The standard procedure used to study ion transport has been to model the T/sub i/ profile with the assumption that the ion thermal diffusivity profile chi/sub i/(r) was equal to a multiplier times chi/sub i//sup neo/(r), the ion thermal diffusivity calculated from neoclassical theory. The multiplier was varied until the calculated T/sub i/ profile agreed with the available ion temperature data, usually T/sub i/(0) or the measured neutron rate. Values of the multiplier in the range of 1 to 10 have generally been obtained with few estimates of the uncertainties in these values. Furthermore, there have been few, if any, attempts to calculate chi/sub i/ by modeling the ion temperature profiles in other ways. As a result, the issue as to whether or not the ion transport in tokamaks is in agreement with neoclassical theory has not been definitively answered

  4. Observation of surface discharge on polymer films irradiated by electron beam

    International Nuclear Information System (INIS)

    Komatsubara, Minoru; Ishii, Masaru; Tsumura, Eiji.

    1992-01-01

    The surface discharge on dielectric surfaces of a spacecraft caused by spacecraft charging is simulated by using a high vacuum chamber equipped with an electron beam gun. Fluoroethylene-propylene (FEP) and polyethleneterephthalate (PET) films frequently employed as thermal control materials are irradiated by an electron beam until surface discharges occur, then the spectrum and waveform of emitted light of discharge, together with the current waveform of the discharge and the mass spectrum of the gas in the vacuum chamber are measured. In the range of 300 through 700 nm of the wavelength, light emission from CN radicals, C 2 radicals, CH radicals and hydrogen atoms are detected. From this result, it is suggested that water molecules in the residual gas and molecules in the structure of the specimen contribute the light emission. The spectroscopic observation of the light emission suggests that the discharge energy is concentrated on PET more than that on FEP. (author)

  5. Large scale atomistic approaches to thermal transport and phonon scattering in nanostructured materials

    Science.gov (United States)

    Savic, Ivana

    2012-02-01

    Decreasing the thermal conductivity of bulk materials by nanostructuring and dimensionality reduction, or by introducing some amount of disorder represents a promising strategy in the search for efficient thermoelectric materials [1]. For example, considerable improvements of the thermoelectric efficiency in nanowires with surface roughness [2], superlattices [3] and nanocomposites [4] have been attributed to a significantly reduced thermal conductivity. In order to accurately describe thermal transport processes in complex nanostructured materials and directly compare with experiments, the development of theoretical and computational approaches that can account for both anharmonic and disorder effects in large samples is highly desirable. We will first summarize the strengths and weaknesses of the standard atomistic approaches to thermal transport (molecular dynamics [5], Boltzmann transport equation [6] and Green's function approach [7]) . We will then focus on the methods based on the solution of the Boltzmann transport equation, that are computationally too demanding, at present, to treat large scale systems and thus to investigate realistic materials. We will present a Monte Carlo method [8] to solve the Boltzmann transport equation in the relaxation time approximation [9], that enables computation of the thermal conductivity of ordered and disordered systems with a number of atoms up to an order of magnitude larger than feasible with straightforward integration. We will present a comparison between exact and Monte Carlo Boltzmann transport results for small SiGe nanostructures and then use the Monte Carlo method to analyze the thermal properties of realistic SiGe nanostructured materials. This work is done in collaboration with Davide Donadio, Francois Gygi, and Giulia Galli from UC Davis.[4pt] [1] See e.g. A. J. Minnich, M. S. Dresselhaus, Z. F. Ren, and G. Chen, Energy Environ. Sci. 2, 466 (2009).[0pt] [2] A. I. Hochbaum et al, Nature 451, 163 (2008).[0pt

  6. Enhancing Low-Grade Thermal Energy Recovery in a Thermally Regenerative Ammonia Battery Using Elevated Temperatures

    KAUST Repository

    Zhang, Fang

    2015-02-13

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA. A thermally regenerative ammonia battery (TRAB) is a new approach for converting low-grade thermal energy into electricity by using an ammonia electrolyte and copper electrodes. TRAB operation at 72°C produced a power density of 236±8 Wm-2, with a linear decrease in power to 95±5 Wm-2 at 23°C. The improved power at higher temperatures was due to reduced electrode overpotentials and more favorable thermodynamics for the anode reaction (copper oxidation). The energy density varied with temperature and discharge rates, with a maximum of 650 Whm-3 at a discharge energy efficiency of 54% and a temperature of 37°C. The energy efficiency calculated with chemical process simulation software indicated a Carnot-based efficiency of up to 13% and an overall thermal energy recovery of 0.5%. It should be possible to substantially improve these energy recoveries through optimization of electrolyte concentrations and by using improved ion-selective membranes and energy recovery systems such as heat exchangers.

  7. Gas-dynamic effects in the interaction of a motionless optical pulsating discharge with gas

    International Nuclear Information System (INIS)

    Tishchenko, V N; Grachev, G N; Smirnov, A L; Pavlov, A A; Pavlov, A A; Golubev, M P

    2008-01-01

    The effect of energy removal from the combustion zone of a motionless optical pulsating discharge in the horizontal direction along the axis of a repetitively pulsed laser beam producing the discharge is discovered. The directivity diagram of a hot gas flow is formed during the action of hundreds of pulses. The effect is observed for short pulse durations, when the discharge efficiently generates shock waves. For long pulse durations, the heated gas propagates upward, as in a thermal source. (laser applications and other topics in quantum electronics)

  8. 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.

  9. Using limnological and optical knowledge to detect discharges from nuclear facilities - Potential application of satellite imagery for international safeguards

    International Nuclear Information System (INIS)

    Borstad, G.; Truong, Q.S. Bob; Keeffe, R.; Baines, P.; Staenz, K.; Neville, R.

    2001-01-01

    Previous work carried out under the Canadian Safeguards Support Program, has shown that thermal imagery from the American Landsat satellites could be used to detect the cooling water discharges, and could therefore be used to verify the operational status of nuclear facilities. In some images, thermal plumes could be easily detected in single band imagery with no mathematical manipulation and little image enhancement because there was a very strong thermal contrast between the effluent and the receiving water. However, for certain situations such as discharges into well mixed conditions (cold water and violent tides) the thermal plume may be more subtle. We show here that the visible bands of Landsat and IKONOS images often contain additional information, and that the thermal signature of a discharge from a nuclear facility is not the only signal available to describe its operation. This paper introduces some important hydrological phenomena that govern the biological and physical organization of water bodies, and discusses some basic concepts of marine and aquatic optics that are relevant to the safeguards problem. Using image analysis techniques that have been used widely in ocean optics work and in applications in the mapping and monitoring of water quality, we have re-analyzed data that were obtained under a joint project between various Canadian government departments. We present a preliminary examination of imagery from both satellite multispectral and aircraft hyperspectral sensors, and discuss methods to extract information that could be useful in the detection and verification of declared or undeclared nuclear activities. In one example of an IKONOS image of the Canadian Bruce Nuclear Generating Facility, simple enhancement techniques failed to find any plume other than a small jet visible in the surface wave field. With knowledge of limnology, oceanography and aquatic optics, we have been able to separate and remove the surface reflection, and detect a

  10. Influence of an additional ballast volume on a pulsed ICP discharge

    International Nuclear Information System (INIS)

    Bogdanov, E A; Jr, C A DeJoseph; Demidov, V I; Kudryavtsev, A A; Serditov, K Yu

    2007-01-01

    A spatial and temporal numerical simulation has been carried out of a pulsed (100% modulated), rf inductively coupled plasma discharge in argon, connected to an additional (ballast) diffusion chamber of much larger volume. It is demonstrated that during the active phase, the presence of the large ballast volume has a small impact on the parameters of the plasma in the smaller discharge chamber. In this case the plasma parameters in the discharge chamber can be estimated separately from the diffusion chamber by a standard method using the characteristic ambipolar diffusion time (for example, using a global model). However, during the afterglow phase, the situation is changed significantly. In the afterglow, the densities of charged particles in the discharge chamber become lower than in the large ballast chamber due to more rapid diffusion loss. As a result, the reverse of the active phase situation occurs, namely, the plasma does not flow from the small to the large chamber, but in the opposite direction, from diffusive to discharge volume, and both the plasma density gradient and the self-consistent ambipolar electric field in the small chamber change directions. This phenomenon leads to new effects in the discharge volume, in particular a decreasing rate of decay of densities of charged particles and electron temperature. Thus, in the afterglow the presence of a large additional ballast volume has a significant impact on the plasma transport. In this case, a simple treatment of the plasma in the discharge chamber in the framework of a spatially averaged model (for example, the global model) is inadequate

  11. The use of large area silicon sensors for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Schulte, R.L. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States)); Swanson, F. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States)); Kesselman, M. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States))

    1994-12-30

    The use of large area planar silicon detectors coupled with gadolinium foils has been investigated to develop a thermal neutron detector having a large area-efficiency (A[epsilon]) product. Noise levels due to high detector capacitance limit the size of silicon detectors that can be utilized. Calculations using the Monte Carlo code, MCNP, have been made to determine the variation of intrinsic detection efficiency as a function of the discriminator threshold level required to eliminate the detector noise. Measurements of the noise levels for planar silicon detectors of various resistivities (400, 3000 and 5000 [Omega] cm) have been made and the optimal detector area-efficiency products have been determined. The response of a Si-Gd-Si sandwich detector with areas between 1 cm[sup 2] and 10.5 cm[sup 2] is presented and the effects of the detector capacitance and reverse current are discussed. ((orig.))

  12. Microinstability-based model for anomalous thermal confinement in tokamaks

    International Nuclear Information System (INIS)

    Tang, W.M.

    1986-03-01

    This paper deals with the formulation of microinstability-based thermal transport coefficients (chi/sub j/) for the purpose of modelling anomalous energy confinement properties in tokamak plasmas. Attention is primarily focused on ohmically heated discharges and the associated anomalous electron thermal transport. An appropriate expression for chi/sub e/ is developed which is consistent with reasonable global constraints on the current and electron temperature profiles as well as with the key properties of the kinetic instabilities most likely to be present. Comparisons of confinement scaling trends predicted by this model with the empirical ohmic data base indicate quite favorable agreement. The subject of anomalous ion thermal transport and its implications for high density ohmic discharges and for auxiliary-heated plasmas is also addressed

  13. The effect of the ergodic divertor on electron thermal confinement

    International Nuclear Information System (INIS)

    Harris, G.R.; Capes, H.; Garbet, X.

    1992-06-01

    The thermal confinement within the confinement zone of Tore Supra ohmically heated deuterium plasmas bounded by the ergodic divertor (ED) configuration is studied in a 1 1/2D analysis of the local power balance. Although the edge electron temperature and mean electron density (n e ) are both on average halved with application of the ED, the mean electron thermal diffusivity χ e shows the same density dependence as exhibited by standard ohmic limiter discharges, i.e., an Alcator-like inverse dependence on (n e ) at low density and a saturation at high density. The ion thermal transport at low to medium densities in both limiter and ED discharges is between 10 to 20 times that predicted by neoclassical theory. Comparing ED and limiter plasmas of the same density, a strong plasma decontamination is observed, with a reduction, in Z eff by between 1.0 to 1.5. The effective decoupling of (n e ) and Z eff by the ED and the invariant behaviour of χ e imply that electron thermal transport is only weakly dependent on Z eff in ohmic Tore Supra discharges

  14. DBD-Corona Discharge for Degradation of Toxic Gases

    International Nuclear Information System (INIS)

    Pacheco-Pacheco, M.; Pacheco-Sotelo, J.; Moreno-Saavedra, H.; Diaz-Gomez, J. A.; Mercado-Cabrera, A.; Yousfi, M.

    2007-01-01

    The non-thermal plasma technology is a promising technique to treat SO 2 and NO x . Chemical radicals produced with this technology can remove several pollutants at atmospheric pressure in a very short period of time simultaneously. Both theoretical and experimental study on SO 2 and NO x removal, by a dielectric barrier discharge (DBD) with corona effect, is presented

  15. Overvoltage effect on electrical discharge type in medium-conductivity water in inhomogeneous pulsed electric field

    Science.gov (United States)

    Panov, V. A.; Vasilyak, L. M.; Pecherkin, V. Ya; Vetchinin, S. P.; Son, E. E.

    2018-01-01

    The transition between thermal and streamer discharges has been observed experimentally in water solution with conductivity 100 μS/cm applying positive voltage pulses to pin-to-rod electrodes. The transition happens at five-fold pulse amplitude. Considering streamer propagation as an ionization wave helped to establish relation between the parameters governing transition from one to another discharge mechanism.

  16. Characterization factors for thermal pollution in freshwater aquatic environments.

    Science.gov (United States)

    Verones, Francesca; Hanafiah, Marlia Mohd; Pfister, Stephan; Huijbregts, Mark A J; Pelletier, Gregory J; Koehler, Annette

    2010-12-15

    To date the impact of thermal emissions has not been addressed in life cycle assessment despite the narrow thermal tolerance of most aquatic species. A method to derive characterization factors for the impact of cooling water discharges on aquatic ecosystems was developed which uses space and time explicit integration of fate and effects of water temperature changes. The fate factor is calculated with a 1-dimensional steady-state model and reflects the residence time of heat emissions in the river. The effect factor specifies the loss of species diversity per unit of temperature increase and is based on a species sensitivity distribution of temperature tolerance intervals for various aquatic species. As an example, time explicit characterization factors were calculated for the cooling water discharge of a nuclear power plant in Switzerland, quantifying the impact on aquatic ecosystems of the rivers Aare and Rhine. The relative importance of the impact of these cooling water discharges was compared with other impacts in life cycle assessment. We found that thermal emissions are relevant for aquatic ecosystems compared to other stressors, such as chemicals and nutrients. For the case of nuclear electricity investigated, thermal emissions contribute between 3% and over 90% to Ecosystem Quality damage.

  17. Plasma chemistry in an atmospheric pressure Ar/NH3 dielectric barrier discharge

    DEFF Research Database (Denmark)

    Fateev, A.; Leipold, F.; Kusano, Y.

    2005-01-01

    An atmospheric pressure dielectric barrier discharge (DBD) in Ar/NH3 (0.1 - 10%) mixtures with a parallel plate electrode geometry was studied. The plasma was investigated by emission and absorption spectroscopy in the UV spectral range. Discharge current and voltage were measured as well. UV...... of an atmospheric pressure Ar/NH3 DBD are H-2, N-2 and N2H4. The hydrazine (N2H4) concentration in the plasma and in the exhaust gases at various ammonia concentrations and different discharge powers was measured. Thermal N2H4 decomposition into NH2 radicals may be used for NOx reduction processes....

  18. Confinement and gas fueling in LHD limiter discharges

    International Nuclear Information System (INIS)

    Nishimura, K.; Kawahata, K.; Narihara, K.; Morisaki, T.; Masuzaki, S.; Sakakibara, S.; Tanaka, K.

    2003-01-01

    Plasma discharges in the Large Helical Device are normally open helical divertor discharges. To compare limiter discharges with open divertor discharges and to examine the role of the peripheral region, a radial movable limiter, whose head was made of carbon with high heat conductivity, was inserted into the plasma from the high field side (near the helical coil). The electron temperature was bounded well by the limiter. A high temperature gradient at the edge region was observed in both open divertor and limiter discharges. Formation of such a high temperature gradient led to good energy confinement even in the limiter discharges and an enhancement factor of 1.1±0.3 for International Stellarator Scaling 95 (ISS95) scaling was observed at every limiter position (0.75 ax =3.75 m prevents gas fueling by puffing

  19. Effect of Water-Air Clearing on Thermal Mixing in IRWST Using Three-Dimensional CFD Analysis

    International Nuclear Information System (INIS)

    Ha, Jeong Hee; Lee, Doo Yong; Hong, Soon Joon; Jeong, Jae Sik; Park, Man Heung; Moon, Young Tae

    2013-01-01

    In this paper, the water-air clearing effects on thermal mixing in the IRWST were investigated with the CFD simulation. The boundary conditions for each discharge phase were obtained from the RELAP5 simulation. The flow distribution in the IRWST for the water clearing phase was reflected as the initial condition for the air clearing simulation. The flow distribution for the air clearing phase was applied as the initial condition for the steam condensation phase. The result of the steam condensation phase with the SCRM showed that the thermal mixing in the IRWST might be enhanced by the mixing effects of the water-air clearing before the steam discharge. IRWST (in-containment refueling water storage tank) is one of the advanced design features of APR1400 (Advanced Power Reactor . 1400). Connected to the Safety Depressurization and Vent System (SDVS), IRWST is designed to absorb the high energy flow from Pilot Operated Safety and Relief Valves (POSRVs) to protect the over-pressurization of the Reactor Coolant System. Due to thermal hydraulic loads induced by discharged fluids, it is crucial to understand the phenomena occur in the IRWST and thermal mixing is one of them. It has been known that the unstable steam condensation which results in oscillations and acts as the loads on the IRWST wall and structures can occur if there is a large local temperature difference. Thus, there is a regulation related to IRWST temperature distribution (difference) to be satisfied. To understand the phenomena and design the IRWST with sufficient safety margin, many experimental and numerical researches have been performed. The results of these researches showed that the CFD analysis predicts well the temperature distribution in the pool globally and can be a proper evaluation methodology to analyze the complex thermal mixing phenomena in the IRWST with a sufficiently fine mesh distribution and proper numerical models. But the previous studies have tended to focus the phenomenological

  20. Microhollow cathode discharge stability with flow and reaction

    International Nuclear Information System (INIS)

    Hsu, David D; Graves, David B

    2003-01-01

    Under certain conditions, microhollow cathode (MHC) discharges display self-pulsing, with relaxation oscillations in voltage (V d ) and current (I d ). An equivalent circuit model of the discharge and circuit demonstrates that relaxation oscillations occur only if the load line crosses the discharge characteristic in the region of negative differential resistivity R d ≡ ∂V d /∂I d . The pulsing and steady-state current regimes could have implications on the use of the discharges as reactors. We present measurements and model results in a study of high pressure MHC discharges as flow reactors in the steady-state current regime. Flow of molecular gases through the intense discharge induces chemical modifications such as molecular decomposition. The MHC behaves approximately as a plug flow reactor with reactant conversion depending primarily on residence time in the plasma. Measured peak gas temperatures in the plasma of the order of 1000-2000 K suggest that endothermic reaction conversion should be thermodynamically favoured. Comparisons to literature values of thermal decomposition kinetics indicate that the MHC plasma has the decomposition activity of gas at 2000-3000 K. High gas temperatures and molecular dissociation induce a significant pressure drop through the plasma. A model calculation for flow through a cylindrical tube containing an intense plasma demonstrates that the increase of pressure drop across the plasma zone is due to the increase in gas mass-averaged velocity as a result of lower mass density associated with the temperature increase and creation of molecular fragments

  1. Response of lead-acid batteries to chopper-controlled discharge

    Science.gov (United States)

    Cataldo, R. L.

    1978-01-01

    The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses at up to 25 percent compared to constant current discharges at the same average discharge current of 100 A. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-A pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

  2. Suppression of the Thermal Decomposition Reaction of Forest Combustible Materials in Large-Area Fires

    Science.gov (United States)

    Volkov, R. S.; Zhdanova, A. O.; Kuznetsov, G. V.; Strizhak, P. A.

    2018-05-01

    Experimental investigations on the characteristic time of suppression of the thermal decomposition reaction of typical forest combustible materials (aspen twigs, birch leaves, spruce needles, pine chips, and a mixture of these materials) and the volume of water required for this purpose have been performed for model fire hotbeds of different areas: SFCM = 0.0003-0.007 m2 and SFCM = 0.045-0.245 m2. In the experiments, aerosol water flows with droplets of size 0.01-0.25 mm were used for the spraying of model fire hotbeds, and the density of spraying was 0.02 L/(m2·s). It was established that the characteristics of suppression of a fire by an aerosol water flow are mainly determined by the sizes of the droplets in this flow. Prognostic estimates of changes in the dispersivity of a droplet cloud, formed from large (as large as 0.5 L) "drops" (water agglomerates) thrown down from a height, have been made. It is shown that these changes can influence the conditions and characteristics of suppression of a forest fire. Dependences, allowing one to forecast the characteristics of suppression of the thermal decomposition of forest combustible materials with the use of large water agglomerates thrown down from an aircraft and aerosol clouds formed from these agglomerates in the process of their movement to the earth, are presented.

  3. Suppression of the Thermal Decomposition Reaction of Forest Combustible Materials in Large-Area Fires

    Science.gov (United States)

    Volkov, R. S.; Zhdanova, A. O.; Kuznetsov, G. V.; Strizhak, P. A.

    2018-03-01

    Experimental investigations on the characteristic time of suppression of the thermal decomposition reaction of typical forest combustible materials (aspen twigs, birch leaves, spruce needles, pine chips, and a mixture of these materials) and the volume of water required for this purpose have been performed for model fire hotbeds of different areas: SFCM = 0.0003-0.007 m2 and SFCM = 0.045-0.245 m2. In the experiments, aerosol water flows with droplets of size 0.01-0.25 mm were used for the spraying of model fire hotbeds, and the density of spraying was 0.02 L/(m2·s). It was established that the characteristics of suppression of a fire by an aerosol water flow are mainly determined by the sizes of the droplets in this flow. Prognostic estimates of changes in the dispersivity of a droplet cloud, formed from large (as large as 0.5 L) "drops" (water agglomerates) thrown down from a height, have been made. It is shown that these changes can influence the conditions and characteristics of suppression of a forest fire. Dependences, allowing one to forecast the characteristics of suppression of the thermal decomposition of forest combustible materials with the use of large water agglomerates thrown down from an aircraft and aerosol clouds formed from these agglomerates in the process of their movement to the earth, are presented.

  4. Thermal effect-resilient design of large mode area double-cladding Yb-doped photonic crystal fibers

    DEFF Research Database (Denmark)

    Coscelli, Enrico; Poli, Federica; Johansen, Mette Marie

    2013-01-01

    The effects of thermally-induced refractive index change on the guiding properties of different large mode area fibers have been numerically analyzed. A simple but accurate model has been applied to obtain the refractive index change in the fiber cross-section, and a full-vector modal solver base...

  5. Physical aspects of mercury-free high pressure discharge lamps

    International Nuclear Information System (INIS)

    Born, M.

    2002-01-01

    This paper gives a summary of recent results about the replacement of mercury in high pressure discharge lamps by metallic zinc. Actually, this topic is of high relevance for the lighting industry due to the need of more environmentally friendly products. The work presented here is supported by the German government under contract no. 13N8072. Pure zinc/argon discharges as well as lamps including zinc or mercury and metal halide additives are investigated. Experimental data are compared with model calculations of the energy balance involving the transport of heat and radiation. Since the excitation energies of relevant zinc transistions are lower than for mercury, axis temperatures of pure zinc lamps are about 300 K below the value of mercury arcs. In addition, the thermal conductivity of zinc including the contribution of radiation diffusion is larger than compared to mercury. From lamp voltage measurements it is found that the cross section for elastical electron scattering by zinc atoms is about the same as for mercury. When adding metal halides to a pure zinc discharge with argon as a starting gas, i.e. NaI, TlI, DyI3, axis temperatures decrease to about 5100 K due to strong radiation cooling. In order to obtain sufficiently large lamp voltages, wall temperatures of more than 1300 K are adjusted by means of polycrystalline aluminaoxide (Al2O3) as a wall material. Electrical field strenghts of 6.0 V/mm and 8.6 V/mm are measured for metal halide lamps containing zinc or mercury, respectively. The light technical data of the discharges are very close, since mercury and zinc do not contribute significantly to the radiation in the visible range. Efficacies of up to 93 lm/W and 100 lm/W are found in metal halide lamps with zinc and mercury, respectively. Consequently, zinc turns out to be an attractive replacer for mercury in this type of lamp not only from an environmental point of view

  6. Growth of wrinkle-free graphene on texture-controlled platinum films and thermal-assisted transfer of large-scale patterned graphene.

    Science.gov (United States)

    Choi, Jae-Kyung; Kwak, Jinsung; Park, Soon-Dong; Yun, Hyung Duk; Kim, Se-Yang; Jung, Minbok; Kim, Sung Youb; Park, Kibog; Kang, Seoktae; Kim, Sung-Dae; Park, Dong-Yeon; Lee, Dong-Su; Hong, Suk-Kyoung; Shin, Hyung-Joon; Kwon, Soon-Yong

    2015-01-27

    Growth of large-scale patterned, wrinkle-free graphene and the gentle transfer technique without further damage are most important requirements for the practical use of graphene. Here we report the growth of wrinkle-free, strictly uniform monolayer graphene films by chemical vapor deposition on a platinum (Pt) substrate with texture-controlled giant grains and the thermal-assisted transfer of large-scale patterned graphene onto arbitrary substrates. The designed Pt surfaces with limited numbers of grain boundaries and improved surface perfectness as well as small thermal expansion coefficient difference to graphene provide a venue for uniform growth of monolayer graphene with wrinkle-free characteristic. The thermal-assisted transfer technique allows the complete transfer of large-scale patterned graphene films onto arbitrary substrates without any ripples, tears, or folds. The transferred graphene shows high crystalline quality with an average carrier mobility of ∼ 5500 cm(2) V(-1) s(-1) at room temperature. Furthermore, this transfer technique shows a high tolerance to variations in types and morphologies of underlying substrates.

  7. On the physical processes ruling an atmospheric pressure air glow discharge operating in an intermediate current regime

    International Nuclear Information System (INIS)

    Prevosto, L.; Mancinelli, B.; Chamorro, J. C.; Cejas, E.; Kelly, H.

    2015-01-01

    Low-frequency (100 Hz), intermediate-current (50 to 200 mA) glow discharges were experimentally investigated in atmospheric pressure air between blunt copper electrodes. Voltage–current characteristics and images of the discharge for different inter-electrode distances are reported. A cathode-fall voltage close to 360 V and a current density at the cathode surface of about 11 A/cm 2 , both independent of the discharge current, were found. The visible emissive structure of the discharge resembles to that of a typical low-pressure glow, thus suggesting a glow-like electric field distribution in the discharge. A kinetic model for the discharge ionization processes is also presented with the aim of identifying the main physical processes ruling the discharge behavior. The numerical results indicate the presence of a non-equilibrium plasma with rather high gas temperature (above 4000 K) leading to the production of components such as NO, O, and N which are usually absent in low-current glows. Hence, the ionization by electron-impact is replaced by associative ionization, which is independent of the reduced electric field. This leads to a negative current-voltage characteristic curve, in spite of the glow-like features of the discharge. On the other hand, several estimations show that the discharge seems to be stabilized by heat conduction; being thermally stable due to its reduced size. All the quoted results indicate that although this discharge regime might be considered to be close to an arc, it is still a glow discharge as demonstrated by its overall properties, supported also by the presence of thermal non-equilibrium

  8. Chemical and isotopic study of thermal springs and gas discharges from Sierra de Chiapas, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Nencetti, A; Tassi, F; Vaselli, O [Department of Earth Sciences, Florence (Italy); Macias, J. L [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, D.F. (Mexico); Magro, G [CNR-Institute of Geosciences and Earth Resources, Pisa (Italy); Capaccioni, B [Institute of Volcanology and Geochemistry, Urbino (Italy); Minissale, A [CNR-Institute of Geosciences and Earth Resources, Florence (Italy); Mora, J. C [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, D.F. (Mexico)

    2005-01-15

    Thermal water and gas discharges south-east of El Chichon volcano, Mexico are associated mainly with NW-SE oriented fault systems. Spring discharges include i) waters with Na-Cl composition and TDS>3000 mg/L; ii) waters with Ca-SO{sub 4} composition and TDS values between 1400 and 2300 mg/L; iii) waters with Na-Cl composition and TDS of 800 to 2400 mg/L and sulphate content up to 650 mg/L and iv) waters with Ca-HCO{sub 3} composition and low salinity (TDS <250mg/L). Most of these waters are associated with free-gas discharges of N{sub 2} (up to 93 % by vol.), CO{sub 2} (2.4 to 31.2 % by vol.) and Ar (up to 1.25 % by vol.) with a predominant meteoric origin. H{sub 2}S is present only in gas samplers collected at El Azufre (up to 1.1 % by vol.). The {delta}13C CO{sub 2} values are always below -9.7% (PDB) and suggest a partially biogenic origin for CO{sub 2}. Chemical and isotopic features of spring discharges indicate that fluid circulation in the Sierra de Chiapas is mainly regulated by meteoric waters that tend to infiltrate the upper and middle-Cretaceous carbonate units up to the lower Cretaceous-upper Jurassic evaporitic formations (by Lopez-Ramos, 1982). The latter provide the main source of the species in solution. No evidence for high-to-medium enthalpy systems at depth beneath the Sierra de Chiapas has been found. [Spanish] La Sierra de Chiapas localizada en el Sureste de Mexico, se caracteriza por la presencia de descargas de gas y agua. La mayoria de los manantiales termales se asocian a rocas volcanicas Terciarias a lo largo de fallas regionales con orientacion NOSE. Las descargas termales se dividen en cuatro grupos: i) aguas con composicion Na-Cl y Solidos Disueltos Totales (SDT) >3000 mg/L; ii) aguas con composicion Ca-SO{sub 4} y valores de SDT entre 1400 y 2300 mg/L; iii) aguas con composicion Na-Cl, bajos contenidos de SDT (800 2400 mg/L) y un contenido de sulfato alto (hasta 650 mg/L) y iv) aguas con una composicion Ca-HCO{sub 3} y salinidad baja

  9. Effects of groundwater withdrawals from the Hurricane Fault zone on discharge of saline water from Pah Tempe Springs, Washington County, Utah

    Science.gov (United States)

    Gardner, Philip M.

    2018-04-10

    Pah Tempe Springs, located in Washington County, Utah, contribute about 95,000 tons of dissolved solids annually along a 1,500-foot gaining reach of the Virgin River. The river gains more than 10 cubic feet per second along the reach as thermal, saline springwater discharges from dozens of orifices located along the riverbed and above the river on both banks. The spring complex discharges from fractured Permian Toroweap Limestone where the river crosses the north-south trending Hurricane Fault. The Bureau of Reclamation Colorado River Basin Salinity Control Program is evaluating the feasibility of capturing and desalinizing the discharge of Pah Tempe Springs to improve downstream water quality in the Virgin River. The most viable plan, identified by the Bureau of Reclamation in early studies, is to capture spring discharge by pumping thermal groundwater from within the Hurricane Fault footwall damage zone and to treat this water prior to returning it to the river.Three multiple-day interference tests were conducted between November 2013 and November 2014, wherein thermal groundwater was pumped from fractured carbonate rock in the fault damage zone at rates of up to 7 cubic feet per second. Pumping periods for these tests lasted approximately 66, 74, and 67 hours, respectively, and the tests occurred with controlled streamflows of approximately 2.0, 3.5, and 24.5 cubic feet per second, respectively, in the Virgin River upstream from the springs reach. Specific conductance, water temperature, and discharge were monitored continuously in the river (upstream and downstream of the springs reach) at selected individual springs, and in the pumping discharge during each of the tests. Water levels were monitored in three observation wells screened in the thermal system. Periodic stream and groundwater samples were analyzed for dissolved-solids concentration and the stable isotopes of oxygen and hydrogen. Additional discrete measurements of field parameters (specific

  10. Proportional and Integral Thermal Control System for Large Scale Heating Tests

    Science.gov (United States)

    Fleischer, Van Tran

    2015-01-01

    The National Aeronautics and Space Administration Armstrong Flight Research Center (Edwards, California) Flight Loads Laboratory is a unique national laboratory that supports thermal, mechanical, thermal/mechanical, and structural dynamics research and testing. A Proportional Integral thermal control system was designed and implemented to support thermal tests. A thermal control algorithm supporting a quartz lamp heater was developed based on the Proportional Integral control concept and a linearized heating process. The thermal control equations were derived and expressed in terms of power levels, integral gain, proportional gain, and differences between thermal setpoints and skin temperatures. Besides the derived equations, user's predefined thermal test information generated in the form of thermal maps was used to implement the thermal control system capabilities. Graphite heater closed-loop thermal control and graphite heater open-loop power level were added later to fulfill the demand for higher temperature tests. Verification and validation tests were performed to ensure that the thermal control system requirements were achieved. This thermal control system has successfully supported many milestone thermal and thermal/mechanical tests for almost a decade with temperatures ranging from 50 F to 3000 F and temperature rise rates from -10 F/s to 70 F/s for a variety of test articles having unique thermal profiles and test setups.

  11. Thermal enhancement of charge and discharge cycles for adsorbed natural gas storage

    KAUST Repository

    Rahman, Kazi Afzalur; Loh, Wai Soong; Chakraborty, Anutosh; Saha, Bidyut Baran; Chun, Won Gee; Ng, Kim Choon

    2011-01-01

    The usage of adsorbed natural gas (ANG) storage is hindered by the thermal management during the adsorption and desorption processes. An effective thermal enhancement is thus essential for the development of the ANG technology and the motivation

  12. Thermal System Analysis and Optimization of Large-Scale Compressed Air Energy Storage (CAES

    Directory of Open Access Journals (Sweden)

    Zhongguang Fu

    2015-08-01

    Full Text Available As an important solution to issues regarding peak load and renewable energy resources on grids, large-scale compressed air energy storage (CAES power generation technology has recently become a popular research topic in the area of large-scale industrial energy storage. At present, the combination of high-expansion ratio turbines with advanced gas turbine technology is an important breakthrough in energy storage technology. In this study, a new gas turbine power generation system is coupled with current CAES technology. Moreover, a thermodynamic cycle system is optimized by calculating for the parameters of a thermodynamic system. Results show that the thermal efficiency of the new system increases by at least 5% over that of the existing system.

  13. Thermal motion in proteins: Large effects on the time-averaged interaction energies

    International Nuclear Information System (INIS)

    Goethe, Martin; Rubi, J. Miguel; Fita, Ignacio

    2016-01-01

    As a consequence of thermal motion, inter-atomic distances in proteins fluctuate strongly around their average values, and hence, also interaction energies (i.e. the pair-potentials evaluated at the fluctuating distances) are not constant in time but exhibit pronounced fluctuations. These fluctuations cause that time-averaged interaction energies do generally not coincide with the energy values obtained by evaluating the pair-potentials at the average distances. More precisely, time-averaged interaction energies behave typically smoother in terms of the average distance than the corresponding pair-potentials. This averaging effect is referred to as the thermal smoothing effect. Here, we estimate the strength of the thermal smoothing effect on the Lennard-Jones pair-potential for globular proteins at ambient conditions using x-ray diffraction and simulation data of a representative set of proteins. For specific atom species, we find a significant smoothing effect where the time-averaged interaction energy of a single atom pair can differ by various tens of cal/mol from the Lennard-Jones potential at the average distance. Importantly, we observe a dependency of the effect on the local environment of the involved atoms. The effect is typically weaker for bulky backbone atoms in beta sheets than for side-chain atoms belonging to other secondary structure on the surface of the protein. The results of this work have important practical implications for protein software relying on free energy expressions. We show that the accuracy of free energy expressions can largely be increased by introducing environment specific Lennard-Jones parameters accounting for the fact that the typical thermal motion of protein atoms depends strongly on their local environment.

  14. Thermal motion in proteins: Large effects on the time-averaged interaction energies

    Energy Technology Data Exchange (ETDEWEB)

    Goethe, Martin, E-mail: martingoethe@ub.edu; Rubi, J. Miguel [Departament de Física Fonamental, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Fita, Ignacio [Institut de Biologia Molecular de Barcelona, Baldiri Reixac 10, 08028 Barcelona (Spain)

    2016-03-15

    As a consequence of thermal motion, inter-atomic distances in proteins fluctuate strongly around their average values, and hence, also interaction energies (i.e. the pair-potentials evaluated at the fluctuating distances) are not constant in time but exhibit pronounced fluctuations. These fluctuations cause that time-averaged interaction energies do generally not coincide with the energy values obtained by evaluating the pair-potentials at the average distances. More precisely, time-averaged interaction energies behave typically smoother in terms of the average distance than the corresponding pair-potentials. This averaging effect is referred to as the thermal smoothing effect. Here, we estimate the strength of the thermal smoothing effect on the Lennard-Jones pair-potential for globular proteins at ambient conditions using x-ray diffraction and simulation data of a representative set of proteins. For specific atom species, we find a significant smoothing effect where the time-averaged interaction energy of a single atom pair can differ by various tens of cal/mol from the Lennard-Jones potential at the average distance. Importantly, we observe a dependency of the effect on the local environment of the involved atoms. The effect is typically weaker for bulky backbone atoms in beta sheets than for side-chain atoms belonging to other secondary structure on the surface of the protein. The results of this work have important practical implications for protein software relying on free energy expressions. We show that the accuracy of free energy expressions can largely be increased by introducing environment specific Lennard-Jones parameters accounting for the fact that the typical thermal motion of protein atoms depends strongly on their local environment.

  15. Behavior of large grain UO{sub 2} pellet by new ADU powder

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Y [Nuclear Development Corp., Tokai, Ibaraki (Japan); Doi, S [Mitsubishi Atomic Power Industries Inc., Kobe (Japan); Abeta, S [Mitsubishi Heavy Industries Ltd, Yokohama (Japan); Yamate, K [Kansai Electric Power Co., Inc., Osaka (Japan)

    1997-08-01

    In Japan, high burnup PWR fuel is being developed for assembly discharge burnups from 48 to 55GWd/t. As the pressure in the rods due to fission gas release from the pellets during the long burnup period is an important issue, some kinds of large grain pellets are being investigated in order to reduce fission gas release assuming their behavior will be as predicted by the simple diffusion mode. One kind of large grain pellet is manufactured from the highly sinterable powder produced by the new ADU (ammonium diuranate) process for converting UF{sub 6} gas to UO{sub 2+x} powder. First, we checked the difference in the characteristics of the new active powder and the one in current use by investigating its pelletizing (pressing and sintering), densification, grain growth and microstructure (pore and grain structure). Secondly, we measured the thermal creep, thermal expansion and thermal conductivity of the large grain pellet, in out-of-pile tests. As a results, it was found that the thermal properties of the large grain pellet are the same as those of the current. ADU pellet except for thermal densification and creep behavior. Thirdly, irradiation experiments were performed in the Halden test reactor and the pressure and fuel stack length change in the rods were monitored at power. After irradiation up to about 20GWd/t, PIE has been carried out. It was confirmed that the fission gas release of the large grain pellet is lower and the in-pile densification is smaller than for pellets in current use. The reduction due to the large grain size is lower than expected from the Booth model because the fission gas release rate is very small and the effect of recoil/knockout is comparable to that of diffusion for a low linear heat rate. This paper compares the microstructure of the new pellet with its large grains and pores produced by a performer and a current pellet with normal sized grains and intrinsic pores. It also describes how this comparison relates the in-pile behavior

  16. Modelling of shear effects on thermal and particle transport in advanced Tokamak scenarios

    International Nuclear Information System (INIS)

    Moreau, D.; Voitsekhovitch, I.; Baker, D.R.

    1999-01-01

    Evolution of thermal and particle internal transport barriers (ITBs) is studied by modelling the time-dependent energy and particle balance in DIII-D plasmas with reversed magnetic shear configurations and in JET discharges with monotonic or slightly reversed q-profiles and large ExB rotation shear. Simulations are performed with semi-empirical models for anomalous diffusion and particle pinch. Stabilizing effects of magnetic and ExB rotation shears are included in anomalous particle and heat diffusivity. Shear effects on particle and thermal transport are compared. Improved particle and energy confinement with the formation of an internal transport barrier (ITB) has been produced in DIII-D plasmas during current ramp-up accompanied with neutral beam injection (NBI). These plasmas are characterized by strong reversed magnetic shear and large ExB rotation shear which provide the reduction of anomalous fluxes. The formation of ITB's in the optimized shear (OS) JET scenario starts with strong NBI heating in a target plasma with a flat or slightly reversed q-profile pre-formed during current ramp-up with ion cyclotron resonance heating (ICRH). Our paper presents the modelling of particle and thermal transport for these scenarios. (authors)

  17. Vapour discharges on Nevado del Ruiz during the recent activity: Clues on the composition of the deep hydrothermal system and its effects on thermal springs

    Science.gov (United States)

    Federico, Cinzia; Inguaggiato, Salvatore; Chacón, Zoraida; Londoño, John Makario; Gil, Edwing; Alzate, Diego

    2017-10-01

    The Nevado del Ruiz volcano is considered one of the most active volcanoes in Colombia, which can potentially threaten approximately 600,000 inhabitants. The existence of a glacier and several streams channelling in some main rivers, flowing downslope, increases the risk for the population living on the flank of the volcano in case of unrest, because of the generation of lahars and mudflows. Indeed, during the November 1985 subplinian eruption, a lahar generated by the sudden melting of the glacier killed twenty thousand people in the town of Armero. Moreover, the involvement of the local hydrothermal system has produced in the past phreatic and phreatomagmatic activity, as occurred in 1989. Therefore, the physico-chemical conditions of the hydrothermal system as well as its contribution to the shallow thermal groundwater and freshwater in terms of enthalpy and chemicals require a close monitoring. The phase of unrest occurred since 2010 and culminated with an eruption in 2012, after several years of relative stability, still maintains a moderate alert, as required by the high seismicity and SO2 degassing. In October 2013, a sampling campaign has been performed on thermal springs and stream water, located at 2600-5000 m of elevation on the slope of Nevado del Ruiz, analyzed for water chemistry and stable isotopes. Some of these waters are typically steam-heated (low pH and high sulfate content) by the vapour probably separating from a zoned hydrothermal system. By applying a model of steam-heating, based on mass and enthalpy balances, we have estimated the mass rate of hydrothermal steam discharging in the different springs. The composition of the hottest thermal spring (Botero Londono) is probably representative of a marginal part of the hydrothermal system, having a temperature of 250 °C and low salinity (Cl 1500 mg/l), which suggest, along with the retrieved isotope composition, a chiefly meteoric origin. The vapour discharged at the steam vent "Nereidas" (3600

  18. Investigation of Gas Heating by Nanosecond Repetitively Pulsed Glow Discharges Used for Actuation of a Laminar Methane-Air Flame

    KAUST Repository

    Lacoste, Deanna

    2017-05-24

    This paper reports on the quantification of the heating induced by nanosecond repetitively pulsed (NRP) glow discharges on a lean premixed methane-air flame. The flame, obtained at room temperature and atmospheric pressure, has an M-shape morphology. The equivalence ratio is 0.95 and the thermal power released by the flame is 113 W. The NRP glow discharges are produced by high voltage pulses of 10 ns duration, 7 kV amplitude, applied at a repetition frequency of 10 kHz. The average power of the plasma, determined from current and voltage measurements, is 1 W, i.e. about 0.9 % of the thermal power of the flame. Broadband vibrational coherent anti-Stokes Raman spectroscopy of nitrogen is used to determine the temperature of the flame with and without plasma enhancement. The temperature evolution in the flame area shows that the thermal impact of NRP glow discharges is in the uncertainty range of the technique, i.e., +/- 40 K.

  19. Diagnostics and modeling of high pressure streamer induced discharges

    International Nuclear Information System (INIS)

    Marode, E.; Dessante, P.; Deschamps, N.; Deniset, C.

    2001-01-01

    A great variety of diagnostic has been applied to gain information on basic parameter governing high pressure nonthermal filamentary plasmas (and namely streamer induced filamentary discharges). Apart from electrical diagnostics, gas discharge, in contrast with solid state physics, can greatly benefit from all optical techniques owing to its ''transparent'' state. Emission and absorption spectroscopy, as well as LIF or CARS (talk are given during this meeting on these two techniques) are among such specific possibilities. The figures gained from these diagnostic measurements has generally no meaning by itself. They must be worked out, by means of calibrated former results, and/or by using them as input in high pressure plasma modeling. Mixing experimental and modeling approach is necessary for reaching relevant physical knowledge of the high pressure filamentary discharges processes. It is shown that diffusion, and thermal space and time distribution, must fully be taken into account

  20. Implosive Thermal Plasma Source for Energy Conversion

    Czech Academy of Sciences Publication Activity Database

    Šonský, Jiří; Tesař, Václav; Gruber, Jan; Mašláni, Alan

    2017-01-01

    Roč. 4, č. 1 (2017), s. 87-90 ISSN 2336-2626 Institutional support: RVO:61388998 ; RVO:61389021 Keywords : implosion * thermal plasma * detonation wave Subject RIV: BL - Plasma and Gas Discharge Physics; BL - Plasma and Gas Discharge Physics (UFP-V) OBOR OECD: Fluids and plasma physics (including surface physics); Fluids and plasma physics (including surface physics) (UFP-V) https://ppt.fel.cvut.cz/ppt2017.html#number1

  1. An overview of modeling methods for thermal mixing and stratification in large enclosures for reactor safety analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haihua Zhao; Per F. Peterson

    2010-10-01

    Thermal mixing and stratification phenomena play major roles in the safety of reactor systems with large enclosures, such as containment safety in current fleet of LWRs, long-term passive containment cooling in Gen III+ plants including AP-1000 and ESBWR, the cold and hot pool mixing in pool type sodium cooled fast reactor systems (SFR), and reactor cavity cooling system behavior in high temperature gas cooled reactors (HTGR), etc. Depending on the fidelity requirement and computational resources, 0-D steady state models (heat transfer correlations), 0-D lumped parameter based transient models, 1-D physical-based coarse grain models, and 3-D CFD models are available. Current major system analysis codes either have no models or only 0-D models for thermal stratification and mixing, which can only give highly approximate results for simple cases. While 3-D CFD methods can be used to analyze simple configurations, these methods require very fine grid resolution to resolve thin substructures such as jets and wall boundaries. Due to prohibitive computational expenses for long transients in very large volumes, 3-D CFD simulations remain impractical for system analyses. For mixing in stably stratified large enclosures, UC Berkeley developed 1-D models basing on Zuber’s hierarchical two-tiered scaling analysis (HTTSA) method where the ambient fluid volume is represented by 1-D transient partial differential equations and substructures such as free or wall jets are modeled with 1-D integral models. This allows very large reductions in computational effort compared to 3-D CFD modeling. This paper will present an overview on important thermal mixing and stratification phenomena in large enclosures for different reactors, major modeling methods and their advantages and limits, potential paths to improve simulation capability and reduce analysis uncertainty in this area for advanced reactor system analysis tools.

  2. Environmental effects of large discharges of cooling water. Experiences from Swedish nuclear power plants

    International Nuclear Information System (INIS)

    Ehlin, Ulf; Lindahl, Sture; Neuman, Erik; Sandstroem, Olof; Svensson, Jonny

    2009-07-01

    Monitoring the environmental effects of cooling water intake and discharge from Swedish nuclear power stations started at the beginning of the 1960s and continues to this day. In parallel with long-term monitoring, research has provided new knowledge and methods to optimise possible discharge locations and design, and given the ability to forecast their environmental effects. Investigations into the environmental effects of cooling-water are a prerequisite for the issuing of power station operating permits by the environmental authorities. Research projects have been carried out by scientists at universities, while the Swedish Environmental Protection Agency, the Swedish Board of Fisheries, and the Swedish Meteorological and Hydrological Institute, SMHI, are responsible for the greater part of the investigations as well as of the research work. The four nuclear power plants dealt with in this report are Oskarshamn, Ringhals, Barsebaeck and Forsmark. They were taken into operation in 1972, 1975, 1975 and 1980 resp. - a total of 12 reactors. After the closure of the Barsebaeck plants in 2005, ten reactors remain in service. The maximum cooling water discharge from the respective stations was 115, 165, 50 and 135 m 3 /s, which is comparable to the mean flow of an average Swedish river - c:a 150 m 3 /s. The report summarizes studies into the consequences of cooling water intake and discharge. Radiological investigations made at the plants are not covered by this review. The strategy for the investigations was elaborated already at the beginning of the 1960s. The investigations were divided into pre-studies, baseline investigations and monitoring of effects. Pre-studies were partly to gather information for the technical planning and design of cooling water intake and outlet constructions, and partly to survey the hydrographic and ecological situation in the area. Baseline investigations were to carefully map the hydrography and ecology in the area and their natural

  3. Investigation of plasma potential and pulsed discharge characteristics in enhanced glow discharge plasma immersion ion implantation and deposition

    International Nuclear Information System (INIS)

    Li Liuhe; Lu Qiuyuan; Fu, Ricky K.Y.; Chu, Paul K.

    2009-01-01

    Enhanced glow discharge plasma immersion ion implantation and deposition (EGD-PII and D) does not require external plasma sources. In this technique, the plasma is produced by self-glow discharge when a high negative voltage is applied to the sample. The small-area, pointed-shape hollow anode and large area tabular cathode form an electron-focused electric field. Using a special electric field design, the electrons from either the plasma or target (secondary electrons) are focused to a special hollow anode. As a result of the special electron-focusing field, the self-glow discharge process can be enhanced to achieve effective ion implantation into the substrate. In this work, the plasma potential distribution is investigated in details and the possible pulse discharge mechanism is discussed. The unique characteristics of the pulsed plasma and plasma extinction are studied.

  4. Thermally Optimized Paradigm of Thermal Management (TOP-M)

    Science.gov (United States)

    2017-07-18

    19b. TELEPHONE NUMBER (Include area code) 18-07-2017 Final Technical Jul 2015 - Jul 2017 NICOP - Thermally Optimized Paradigm of Thermal Management ...The main goal of this research was to present a New Thermal Management Approach, which combines thermally aware Very/Ultra Large Scale Integration...SPAD) image sensors were used to demonstrate the new thermal management approach. Thermal management , integrated temperature sensors, Vt extractor

  5. Experimental Investigation of A Heat Pipe-Assisted Latent Heat Thermal Energy Storage System

    Science.gov (United States)

    Tiari, Saeed; Mahdavi, Mahboobe; Qiu, Songgang

    2016-11-01

    In the present work, different operation modes of a latent heat thermal energy storage system assisted by a heat pipe network were studied experimentally. Rubitherm RT55 enclosed by a vertical cylindrical container was used as the Phase Change Material (PCM). The embedded heat pipe network consisting of a primary heat pipe and an array of four secondary heat pipes were employed to transfer heat to the PCM. The primary heat pipe transports heat from the heat source to the heat sink. The secondary heat pipes transfer the extra heat from the heat source to PCM during charging process or retrieve thermal energy from PCM during discharging process. The effects of heat transfer fluid (HTF) flow rate and temperature on the thermal performance of the system were investigated for both charging and discharging processes. It was found that the HTF flow rate has a significant effect on the total charging time of the system. Increasing the HTF flow rate results in a remarkable increase in the system input thermal power. The results also showed that the discharging process is hardly affected by the HTF flow rate but HTF temperature plays an important role in both charging and discharging processes. The authors would like to acknowledge the financial supports by Temple University for the project.

  6. A study on the ocean circulation and thermal diffusion near a nuclear power plant

    International Nuclear Information System (INIS)

    Shu, Kyung Suk; Han, Moon Hee; Kim, Eun Han; Hwang, Won Tae

    1994-08-01

    The thermal discharge used with cooling water at nuclear power plant is released to a neighbour sea and it is influenced on marine environment. The thermal discharge released from power plant is mainly transported and diffused by ocean circulation of neighbour sea. So the evaluation for characteristics of ocean circulation around neighbour sea is firstly performed. The purpose of this research is primarily analyzed the thermal diffusion in sea around Yongkwang nuclear power plant. For this viewpoint, fundamental oceanographic data sets are collected and analyzed in Yellow sea, west sea of Korea, sea around Yongkwang. The ocean circulation and the effects of temperature increase by thermal discharge are evaluated using these data. The characteristics of tide is interpreted by the analysis of observed tidal elevation and tidal currents. The characteristics of temperature and salinity is investigated by the long-term observation of Korea Fisheries Research and Development Agency and the short-term observation around Yongkwang. (Author)

  7. Characteristics of 2-heptanone decomposition using nanosecond pulsed discharge plasma

    Science.gov (United States)

    Nakase, Yuki; Fukuchi, Yuichi; Wang, Douyan; Namihira, Takao; Akiyama, Hidenori; Kumamoto University Collaboration

    2015-09-01

    Volatile organic compounds (VOC) evaporate at room temperature. VOCs typically consist of toluene, benzene and ethyl acetate, which are used in cosmetics, dry cleaning products and paints. Exposure to elevated levels of VOCs may cause headaches, dizziness and irritation to the eyes, nose, and throat; they may also cause environmental problems such as air pollution, acid rain and photochemical smog. As such, they require prompt removal. Nanosecond pulsed discharge is a kind of non-thermal plasma consisting of a streamer discharge. Several advantages of nanosecond pulsed discharge plasma have been demonstrated by studies of our research group, including low heat loss, highly energetic electron generation, and the production of highly active radicals. These advantages have shown ns pulsed discharge plasma capable of higher energy efficiency for processes, such as air purification, wastewater treatment and ozone generation. In this research, nanosecond pulsed discharge plasma was employed to treat 2-heptanone, which is a volatile organic compound type and presents several harmful effects. Characteristics of treatment dependent on applied voltage, gas flow rate and input energy density were investigated. Furthermore, byproducts generated by treatment were also investigated.

  8. [Duration of breast feeding after mandatory early discharge].

    Science.gov (United States)

    Kierkegaard, O

    1993-08-23

    A trial arrangement for mandatory early discharge for all normal multiparae was started in 1990 and the duration of breastfeeding was investigated by a questionnaire. 89 mothers who stayed at the hospital were compared to 113 mothers who were discharged within 24 hours after delivery. The latter group was also compared to 122 early discharged mothers who delivered 14-17 months after the trial arrangement had started. The three groups were comparable in all aspects. After four weeks a large proportion of the later discharged mothers were still breastfeeding compared to the other two groups (p < 0.001). This difference disappeared later, hence when comparing the total duration of breastfeeding no differences were found between the three groups.

  9. Research on simulation of supercritical steam turbine system in large thermal power station

    Science.gov (United States)

    Zhou, Qiongyang

    2018-04-01

    In order to improve the stability and safety of supercritical steam turbine system operation in large thermal power station, the body of the steam turbine is modeled in this paper. And in accordance with the hierarchical modeling idea, the steam turbine body model, condensing system model, deaeration system model and regenerative system model are combined to build a simulation model of steam turbine system according to the connection relationship of each subsystem of steam turbine. Finally, the correctness of the model is verified by design and operation data of the 600MW supercritical unit. The results show that the maximum simulation error of the model is 2.15%, which meets the requirements of the engineering. This research provides a platform for the research on the variable operating conditions of the turbine system, and lays a foundation for the construction of the whole plant model of the thermal power plant.

  10. Sheath heating in low-pressure capacitive radio frequency discharges

    International Nuclear Information System (INIS)

    Wood, B.P.

    1991-01-01

    Capacitively coupled, parallel plate, r.f. discharges are commonly used for materials processing. The electrons in such a discharge gain and lose energy by reflection from the oscillating sheaths which form at the electrodes. Previous models of the electron heating by this mechanism have assumed that the sheath motion is slow compared to the electron thermal velocity, so that the electron energy change from each reflection is small. Here, the heating rate, density, and sheath width relations are derived analytically in the limit of very fast sheath motion. Numerical results are presented spanning the slow and fast limits. Results from particle-in-cell simulations show that in the large-energy-change regime, an electron beam is produced on each sheath expansion. At low pressure, this beam can traverse the plasma and interact with the sheath at the opposite electrode, producing a beam energy and density dependence on the length of the discharge. The beam produces a time and space varying warm tail on the electron energy distribution. Two revised heating models are derived, assuming power-law and two-temperature electron energy distributions, with temporal variation in electron temperature. These revised models yield new predictions for the variation of the power, density, and sheath thickness with applied r.f. voltage. These predictions are compared with simulation results and laboratory experiment. The electron sheath motion is investigated experimentally by observing the signal on a floating probe in the sheath region. This is compared to the signal product by a non-linear circuit model which accounts for the perturbation of the sheath potential by the probe and includes various forms of sheath motion. The experimental observations are consistent with the analytical predictions. Experimental observations of plasma-sheath resonance oscillations are presented which agree with analytical predictions

  11. Electron beam sterilization of water discharged from sewage

    International Nuclear Information System (INIS)

    Miyata, Teijiro; Arai, Hidehiko; Tokunaga, Okihiro; Machi, Sueo; Kondo, Masaki; Minemura, Takashi; Nakao, Akio; Seike, Yasuhiko.

    1989-01-01

    At present, the water treated at city sewerages is discharged to rivers after the chlorine sterilization, but it was clarified recently that this chlorine treatment produces carcinogenic organic chlorine compounds, and residual chlorine exerts harmful effect to aquatics, therefore, it is desirable to develop the sterilization techniques substituting for chlorine treatment. Already many reports elucidated that irradiation is effective for the sterilization of the water discharged from sewerage. However, as the technical subject for putting radiation process in practical use, the treatment of large quantity was a problem. Recently by the progress of the technology of manufacturing electron accelerators, the equipment with large power output which can treat in large quantity was developed, and it has become applicable also to sewage treatment. Therefore, the authors examined the practicality of electron beam process as the substitute technology for chlorine sterilizaiton. In the case of using electron beam, though the power output of accelerators is large, the flight range of electron beam in water is short. The comparison of the sterilization effect of electron beam with that of Co-60 gamma ray, the effects of water depth, discharged water quality and water velocity on the sterilization effect and so on were experimentally examined. (K.I.)

  12. Modelling approaches to thermal pollution in inland aquatic systems and issues related to its environmental impacts

    International Nuclear Information System (INIS)

    Mahadevan, T.N.; Nair, R.N.; Sadasivan, S.

    2002-01-01

    Guidelines for the safe discharge of thermal effluents in aquatic environmental systems both surface water and marine coastal out falls has become very relevant to Indian environmental conditions with its rich biodiversity. While aquatic ecology may form the basis for such guidelines, the need for regulatory approach to the related issues has become the prime mover in thermal discharge problems. This is more so since the impacts considered are under short term and long term exposure conditions where the bio acclimatization and thermal stress factors may come to cross roads. Constant temperatures and cyclic temperature elevations also causes differential thermal stress which could be site specific. The recent notification by the Ministry of Environment and Forest (MoEF) revising the temperature limit for discharge of condenser cooling water from thermal power plants into coastal areas using sea water from 5 deg to 7 degC over and above the ambient temperature of the receiving water bodies. Discussions on whether the limiting temperature is to be achieved at the point of discharge or within a specified zone of the thermal plume is currently being debated. The act also stipulates installation of cooling towers using water from rivers, lakes and reservoirs irrespective of the plant location and capacity. For existing thermal plants the rise in temperature of the condenser cooling water from inlet to the let of the condenser shall not be more than 10 degC. (author)

  13. A progress report for the large block test of the coupled thermal-mechanical-hydrological-chemical processes

    International Nuclear Information System (INIS)

    Lin, W.; Wilder, D.G.; Blink, J.

    1994-10-01

    This is a progress report on the Large Block Test (LBT) project. The purpose of the LBT is to study some of the coupled thermal-mechanical-hydrological-chemical (TMHC) processes in the near field of a nuclear waste repository under controlled boundary conditions. To do so, a large block of Topopah Spring tuff will be heated from within for about 4 to 6 months, then cooled down for about the same duration. Instruments to measure temperature, moisture content, stress, displacement, and chemical changes will be installed in three directions in the block. Meanwhile, laboratory tests will be conducted on small blocks to investigate individual thermal-mechanical, thermal-hydrological, and thermal-chemical processes. The fractures in the large block will be characterized from five exposed surfaces. The minerals on fracture surfaces will be studied before and after the test. The results from the LBT will be useful for testing and building confidence in models that will be used to predict TMHC processes in a repository. The boundary conditions to be controlled on the block include zero moisture flux and zero heat flux on the sides, constant temperature on the top, and constant stress on the outside surfaces of the block. To control these boundary conditions, a load-retaining frame is required. A 3 x 3 x 4.5 m block of Topopah Spring tuff has been isolated on the outcrop at Fran Ridge, Nevada Test Site. Pre-test model calculations indicate that a permeability of at least 10 -15 m 2 is required so that a dryout zone can be created within a practical time frame when the block is heated from within. Neutron logging was conducted in some of the vertical holes to estimate the initial moisture content of the block. It was found that about 60 to 80% of the pore volume of the block is saturated with water. Cores from the vertical holes have been used to map the fractures and to determine the properties of the rock. A current schedule is included in the report

  14. Phenomena of non-thermal electrons from the X-ray imaging crystal spectrometer on J-TEXT tokamak

    International Nuclear Information System (INIS)

    Yan, W.; Chen, Z.Y.; Jin, W.; Huang, D.W.; Lee, S.G.; Shi, Y.J.; Tong, R.H.; Wang, S.Y.; Wei, Y.N.; Ma, T.K.; Zhuang, G.

    2016-01-01

    Highlights: • Some lines from X-ray imaging crystal spectrometer (XICS) can be enhanced by non-thermal electrons, such as q, r satellite lines and z lines. • Analyze the non-thermal phenomena can reduce the error of electron temperature deduced from the intensity ratio of different lines of the He-like argon spectra from XICS. • XICS can be a tool to measure the non-thermal phenomena from these enhanced lines. - Abstract: A high spectra resolution X-ray imaging crystal spectrometer has been implemented on J-TEXT Tokamak for the measurements of K_α spectra of helium-like argon and its satellite lines. The wavelength range of K_α spectra of helium-like argon is from 3.9494 Å to 3.9944 Å that includes the resonance line w, intercombination lines x and y, forbidden line z and numerous satellite lines, referenced using standard Gabriel notation. In low-density discharge, the intensity of q, r satellite lines and z lines can be significantly enhanced by non-thermal electrons. Non-thermal electrons are produced due to the low plasma density. The high hard X-ray flux from NaI detector and significant downshift electron cyclotron emissions from energetic runaway electrons also indicated that there is a large population of runaway electrons in the low-density discharge. The non-thermal part of electrons can affect the excitation/transition equilibrium or ionization/recombination equilibrium. The q line is mainly produced by inner-shell excitation of lithium-like argon, and the r line is partially produced by inner-shell excitation of lithium-like argon and dielectronic recombination of helium-like argon.

  15. Phenomena of non-thermal electrons from the X-ray imaging crystal spectrometer on J-TEXT tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Yan, W. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China); Chen, Z.Y., E-mail: zychen@hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China); Jin, W. [Center of Interface Dynamics for Sustainability, China Academy of Engineering Physics, Chengdu 610200, Sichuan (China); Huang, D.W. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China); Lee, S.G.; Shi, Y.J. [National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Tong, R.H.; Wang, S.Y.; Wei, Y.N.; Ma, T.K.; Zhuang, G. [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan (China)

    2016-11-01

    Highlights: • Some lines from X-ray imaging crystal spectrometer (XICS) can be enhanced by non-thermal electrons, such as q, r satellite lines and z lines. • Analyze the non-thermal phenomena can reduce the error of electron temperature deduced from the intensity ratio of different lines of the He-like argon spectra from XICS. • XICS can be a tool to measure the non-thermal phenomena from these enhanced lines. - Abstract: A high spectra resolution X-ray imaging crystal spectrometer has been implemented on J-TEXT Tokamak for the measurements of K{sub α} spectra of helium-like argon and its satellite lines. The wavelength range of K{sub α} spectra of helium-like argon is from 3.9494 Å to 3.9944 Å that includes the resonance line w, intercombination lines x and y, forbidden line z and numerous satellite lines, referenced using standard Gabriel notation. In low-density discharge, the intensity of q, r satellite lines and z lines can be significantly enhanced by non-thermal electrons. Non-thermal electrons are produced due to the low plasma density. The high hard X-ray flux from NaI detector and significant downshift electron cyclotron emissions from energetic runaway electrons also indicated that there is a large population of runaway electrons in the low-density discharge. The non-thermal part of electrons can affect the excitation/transition equilibrium or ionization/recombination equilibrium. The q line is mainly produced by inner-shell excitation of lithium-like argon, and the r line is partially produced by inner-shell excitation of lithium-like argon and dielectronic recombination of helium-like argon.

  16. Influence of thermal loading on the ecology of intertidal algae

    International Nuclear Information System (INIS)

    Vadas, R.L.; Keser, M.; Rusanowski, P.c.

    1976-01-01

    Thermal effluents from the Maine Yankee Atomic Power Company (operating intermittently from October 1972 to December 1974) increased water temperatures in the discharge area by 7 to 15 0 C. Plant operation and the removal of a causeway increased mixing and salinities in Montsweag Bay. Four small red algae immigrated into the area, but no species were lost from the system. Distribution and abundance patterns of the dominant algae, Ascophyllum nodosum and Fucus vesiculosus, were altered by the thermal discharge. The cover of F. vesiculosus decreased, whereas that of A. nodosum increased in 1973 but declined significantly in 1974. Reductions in biomass and percent cover were accompanied by changes in the growth dynamics of A. nodosum. Growth and survival in the discharge area were enhanced in 1973 but reduced in 1974. Growth was initiated earlier at all sites affected by the warm water. Plants at experimental sites not directly in the discharge channel grew at accelerated rates during the two years, but stressed plants in the discharge produced few or no viable apexes in 1974. The net effect has been a compression and reduction of intertidal algae into a narrower and less dense band

  17. Pancreatitis - discharge

    Science.gov (United States)

    Chronic pancreatitis - discharge; Pancreatitis - chronic - discharge; Pancreatic insufficiency - discharge; Acute pancreatitis - discharge ... You were in the hospital because you have pancreatitis. This is a swelling of the pancreas. You ...

  18. Laser/fluorescent dye flow visualization technique developed for system component thermal hydraulic studies

    International Nuclear Information System (INIS)

    Oras, J.J.; Kasza, K.E.

    1988-01-01

    A novel laser flow visualization technique is presented together with examples of its use in visualizing complex flow patterns and plans for its further development. This technique has been successfully used to study (1) the flow in a horizontal pipe subject to temperature transients, to view the formation and breakup of thermally stratified flow and to determine instantaneous velocity distributions in the same flow at various axial locations; (2) the discharge of a stratified pipe flow into a plenum exhibiting a periodic vortex pattern; and (3) the thermal-buoyancy-induced flow channeling on the shell side of a heat exchanger with glass tubes and shell. This application of the technique to heat exchangers is unique. The flow patterns deep within a large tube bundle can be studied under steady or transient conditions. This laser flow visualization technique constitutes a very powerful tool for studying single or multiphase flows in complex thermal system components

  19. Excited Atoms and Molecules in High Pressure Gas Discharges

    International Nuclear Information System (INIS)

    Vuskovic, L.; Popovic, S.

    2003-01-01

    Various types of high-pressure non-thermal discharges are increasingly drawing attention in view of many interesting applications. These, partially ionized media in non-equilibrium state, tend to generate complex effects that are difficult to interpret without a detailed knowledge of elementary processes involved. Electronically excited molecules and atoms may play an important role as intermediate states in a wide range of atomic and molecular processes, many of which are important in high-pressure discharges. They can serve also as reservoirs of energy or as sources of high energy electrons either through the energy pooling or through superelastic collisions. By presenting the analysis of current situation on the processes involving excited atoms and molecules of interest for high-pressure gas discharges, we will attempt to draw attention on the insufficiency of available data. In the same time we will show how to circumvent this situation and still be able to develop accurate models and interpretations of the observed phenomena

  20. Atmospheric pressure dielectric barrier discharges for sterilization and surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chin, O. H.; Lai, C. K.; Choo, C. Y.; Wong, C. S.; Nor, R. M. [Plasma Technology Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Thong, K. L. [Microbiology Division, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-04-24

    Atmospheric pressure non-thermal dielectric barrier discharges can be generated in different configurations for different applications. For sterilization, a parallel-plate electrode configuration with glass dielectric that discharges in air was used. Gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and Gram-positive bacteria (Bacillus cereus) were successfully inactivated using sinusoidal high voltage of ∼15 kVp-p at 8.5 kHz. In the surface treatment, a hemisphere and disc electrode arrangement that allowed a plasma jet to be extruded under controlled nitrogen gas flow (at 9.2 kHz, 20 kVp-p) was applied to enhance the wettability of PET (Mylar) film.

  1. Large Matched-Index-of-Refraction (MIR) Flow Systems for Thermal Engineering Education

    International Nuclear Information System (INIS)

    McIlroy, Hugh M. Jr.; McEligot, Donald M.; Becker, Stefan

    2011-01-01

    In recent international collaboration, Idaho National Laboratory (INL) and University of Erlangen-Nuremberg (UE) have developed large MIR flow systems which are ideal for joint graduate student education and research. The benefit of the MIR technique is that it permits optical measurements to determine flow characteristics in complex passages and around objects to be obtained without locating a disturbing transducer in the flow field and without distortion of the optical paths. The MIR technique is not new itself; others employed it earlier. The innovation of these MIR systems is their large size relative to previous experiments, yielding improved spatial and temporal resolution. This article will discuss the benefits of the technique, characteristics of the systems and some examples of their applications to complex situations. Typically their experiments have provided new fundamental understanding plus benchmark data for assessment and validation of computational thermal fluid dynamic codes.

  2. Forced transport of thermal energy in magmatic and phreatomagmatic large volume ignimbrites: Paleomagnetic evidence from the Colli Albani volcano, Italy

    Science.gov (United States)

    Trolese, Matteo; Giordano, Guido; Cifelli, Francesca; Winkler, Aldo; Mattei, Massimo

    2017-11-01

    Few studies have detailed the thermal architecture of large-volume pyroclastic density current deposits, although such work has a clear importance for understanding the dynamics of eruptions of this magnitude. Here we examine the temperature of emplacement of large-volume caldera-forming ignimbrites related to magmatic and phreatomagmatic eruptions at the Colli Albani volcano, Italy, by using thermal remanent magnetization analysis on both lithic and juvenile clasts. Results show that all the magmatic ignimbrites were deposited at high temperature, between the maximum blocking temperature of the magnetic carrier (600-630 °C) and the glass transition temperature (about 710 °C). Temperature estimations for the phreatomagmatic ignimbrite range between 200 and 400 °C, with most of the clasts emplaced between 200 and 320 °C. Because all the investigated ignimbrites, magmatic and phreatomagmatic, share similar magma composition, volume and mobility, we attribute the temperature difference to magma-water interaction, highlighting its pronounced impact on thermal dissipation, even in large-volume eruptions. The homogeneity of the deposit temperature of each ignimbrite across its areal extent, which is maintained across topographic barriers, suggests that these systems are thermodynamically isolated from the external environment for several tens of kilometers. Based on these findings, we propose that these large-volume ignimbrites are dominated by the mass flux, which forces the lateral transport of mass, momentum, and thermal energy for distances up to tens of kilometers away from the vent. We conclude that spatial variation of the emplacement temperature can be used as a proxy for determining the degree of forced-convection flow.

  3. Hydrochemistry and groundwater system of the Zerka Ma'in-Zara thermal field, Jordan

    Science.gov (United States)

    Rimawi, Omar; Salameh, Elias

    1988-03-01

    A groundwater flow model through the different geological successions from the Upper Cretaceous through the Lower Cretaceous Sandstone and older units is presented in this paper. The model is supported by the hydrochemical evolution of water types from the recharge areas in the highlands to discharge sites of thermal water at the slopes overlooking the Dead Sea. The thermal water discharged in the Zerka Ma'in-Zara areas consists of three end members mixed in different ratios with a component of old (many thousands of years) thermal water undersaturated in carbonate minerals and containing hundreds of milligrams per liter of free CO 2. The release of CO 2 gas upon discharge renders the water oversaturated with respect to carbonate minerals which results in aragonite precipitation. The elevated temperature of the water in the reservoir (73-82°C) is attributed to the presence of a heat-storing layer topping the aquifer.

  4. Heart pacemaker - discharge

    Science.gov (United States)

    Cardiac pacemaker implantation - discharge; Artificial pacemaker - discharge; Permanent pacemaker - discharge; Internal pacemaker - discharge; Cardiac resynchronization therapy - discharge; CRT - discharge; ...

  5. Timescale and magnitude of plasma thermal energy loss before and during disruptions in JET

    International Nuclear Information System (INIS)

    Riccardo, V.; Loarte, A.

    2005-01-01

    In this paper we analyse and discuss the thermal energy loss dynamics before and during JET disruptions that occurred between 2002 and 2004 in discharges which reached >4.5 MJ of thermal energy. We observe the slow thermal energy transients with diamagnetic loops and the fast ones with electron cyclotron emission and soft x-ray diagnostics. For most disruption types in JET, the plasma thermal energy at the time of the thermal quench is substantially less than that of the full performance plasma, typically in the range of 10-50% depending on plasma conditions and disruption type. The exceptions to this observation are disruptions in plasmas with a strong internal transport barrier (ITB) and in discharges terminating in a pure vertical displacement event, in which the plasma conserves a very high energy content up to the thermal quench. These disruption types are very sudden, leaving little scope for the combined action of soft plasma landing strategies and intrinsic performance degradation, both requiring >500 ms to be effective, to decrease the available thermal energy. The characteristic time for the loss of energy from the main plasma towards the PFCs in the thermal quench of JET disruptions is in the range 0.05-3.0 ms. The shortest timescales are typical of disruptions caused by excessive pressure peaking in ITB discharges. The available thermal energy fraction and thermal quench duration observed in JET can be processed (with due caution) into estimates for the projected PFC lifetime of the ITER target

  6. Waste heat discharges in the aquatic environment -- impact and monitoring 2

    International Nuclear Information System (INIS)

    Kamath, P.R.

    1980-01-01

    Studies on ecological impacts, on fishes in particular, of waste heat discharges in the aquatic environment are briefly reviewed. These studies cover the susceptibility of fishes to disease and predation, population biology, parasite proliferation and its impact on fishes, synergistic effects due to heat and other stresses such as chemicals, pollutant, lowering of saturation limit of dissolved oxygen at elevated temperature and radioactivity. Experiences of monitoring waste heat discharges at the Rajasthan Atomic Power Station (RAPS) and the Tarapur Atomic Power Station (TAPS) are presented. Entrainment losses and impingement losses are also reviewed. Requirements for thermal monitoring are mentioned. (M.G.B.)

  7. Discharge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster

    Science.gov (United States)

    Polzin, K. A.; Sooby, E. S.; Raitses, Y.; Merino, E.; Fisch, N. J.

    2009-01-01

    Measurements of the discharge current in a cylindrical Hall thruster are presented to quantify plasma oscillations and instabilities without introducing an intrusive probe into the plasma. The time-varying component of the discharge current is measured using a current monitor that possesses a wide frequency bandwidth and the signal is Fourier transformed to yield the frequency spectra present, allowing for the identification of plasma oscillations. The data show that the discharge current oscillations become generally greater in amplitude and complexity as the voltage is increased, and are reduced in severity with increasing flow rate. The breathing mode ionization instability is identified, with frequency as a function of discharge voltage not increasing with discharge voltage as has been observed in some traditional Hall thruster geometries, but instead following a scaling similar to a large-amplitude, nonlinear oscillation mode recently predicted in for annular Hall thrusters. A transition from lower amplitude oscillations to large relative fluctuations in the oscillating discharge current is observed at low flow rates and is suppressed as the mass flow rate is increased. A second set of peaks in the frequency spectra are observed at the highest propellant flow rate tested. Possible mechanisms that might give rise to these peaks include ionization instabilities and interactions between various oscillatory modes.

  8. Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

    Directory of Open Access Journals (Sweden)

    P.W. Swarzenski

    2017-06-01

    New hydrological insights for the region: Estimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d mass balance model. Such estimates were complemented with a novel thoron (220Rn, t1/2 = 56 s groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

  9. Shoulder replacement - discharge

    Science.gov (United States)

    Total shoulder arthroplasty - discharge; Endoprosthetic shoulder replacement - discharge; Partial shoulder replacement - discharge; Partial shoulder arthroplasty - discharge; Replacement - shoulder - discharge; Arthroplasty - shoulder - discharge

  10. Thermal deposition analysis during disruptions on DIII-D using infrared scanners

    International Nuclear Information System (INIS)

    Lee, R.L.; Hyatt, A.W.; Kellman, A.G.; Taylor, P.L.; Lasnier, C.J.

    1995-12-01

    The DIII-D tokamak generates plasma discharges with currents up to 3 MA and auxiliary input power up to 20 MW from neutral beams and 4 MW from radio frequency systems. In a disruption, a rapid loss of the plasma current and internal thermal energy occurs and the energy is deposited onto the torus graphite wall. Quantifying the spatial and temporal characteristics of the heat deposition is important for engineering and physics-related issues, particularly for designing future machines such as ITER. Using infrared scanners with a time resolution of 120 micros, measurements of the heat deposition onto the all-graphite walls of DIII-D during two types of disruptions have been made. Each scanner contains a single point detector sensitive to 8--12 microm radiation, allowing surface temperatures from 20 C to 2,000 C to be measured. A zinc selenide window that transmits in the infrared is used as the vacuum window. Views of the upper and lower divertor regions and the centerpost provide good coverage of the first wall for single and double null divertor discharges. During disruptions, the thermal energy is not deposited evenly onto the inner surface of the tokamak, but is deposited primarily in the divertor region when operating diverted discharges. Analysis of the heat deposition during a radiative collapse disruption of a 1.5 MA discharge revealed power densities of 300--350 MW/m 2 in the divertor region. During the thermal quench of the disruption, the energy deposited onto the divertor region was more than 70% of the stored thermal energy in the discharge prior to the disruption. The spatial distribution and temporal behavior of power deposition during high β disruptions will also be presented

  11. Assessing the variability of glacier lake bathymetries and potential peak discharge based on large-scale measurements in the Cordillera Blanca, Peru

    Science.gov (United States)

    Cochachin, Alejo; Huggel, Christian; Salazar, Cesar; Haeberli, Wilfried; Frey, Holger

    2015-04-01

    Over timescales of hundreds to thousands of years ice masses in mountains produced erosion in bedrock and subglacial sediment, including the formation of overdeepenings and large moraine dams that now serve as basins for glacial lakes. Satellite based studies found a total of 8355 glacial lakes in Peru, whereof 830 lakes were observed in the Cordillera Blanca. Some of them have caused major disasters due to glacial lake outburst floods in the past decades. On the other hand, in view of shrinking glaciers, changing water resources, and formation of new lakes, glacial lakes could have a function as water reservoirs in the future. Here we present unprecedented bathymetric studies of 124 glacial lakes in the Cordillera Blanca, Huallanca, Huayhuash and Raura in the regions of Ancash, Huanuco and Lima. Measurements were carried out using a boat equipped with GPS, a total station and an echo sounder to measure the depth of the lakes. Autocad Civil 3D Land and ArcGIS were used to process the data and generate digital topographies of the lake bathymetries, and analyze parameters such as lake area, length and width, and depth and volume. Based on that, we calculated empirical equations for mean depth as related to (1) area, (2) maximum length, and (3) maximum width. We then applied these three equations to all 830 glacial lakes of the Cordillera Blanca to estimate their volumes. Eventually we used three relations from the literature to assess the peak discharge of potential lake outburst floods, based on lake volumes, resulting in 3 x 3 peak discharge estimates. In terms of lake topography and geomorphology results indicate that the maximum depth is located in the center part for bedrock lakes, and in the back part for lakes in moraine material. Best correlations are found for mean depth and maximum width, however, all three empirical relations show a large spread, reflecting the wide range of natural lake bathymetries. Volumes of the 124 lakes with bathymetries amount to 0

  12. Study for discharge coefficient of flow nozzles. Prediction by using numerical simulation

    International Nuclear Information System (INIS)

    Ikeda, Hiroshi; Sakai, Norio; Yamamoto, Yasushi; Arai, Kenji; Matsumoto, Masaaki

    2008-01-01

    In nuclear plant, as water feeding into reactor have much effect on thermal power of plant, it is important to measure accurately the flow rate of water. Flow nozzle is on of typical differential pressure type flow meters and the discharge coefficient is used to calculate the flow rate. This coefficient is given by actual experiment and theory. We studied the theoretical assumption of the discharge coefficient curve using numerical simulation and evaluated the effect of flow nozzle configuration on the coefficient numerically and experimentally. As the result, numerical simulation can predict the discharge coefficient of theoretical curve within 0.3%. And we found that the throat length and throat tapping location of flow nozzle have much effect on the coefficient. (author)

  13. Prospects for solving environmental problems pertinent to thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    A.G. Tumanovskii; V.R. Kotler [OAO All-Russia Thermal Engineering Institute, Moscow (Russian Federation)

    2007-06-15

    Possible ways to protect the atmosphere and water basin against harmful emissions and effluent waters discharged from thermal power stations are considered. Data on the effectiveness of different methods for removing NOx, SO{sub 2}, and ash particles, as well as heavy metals and CO{sub 2}, from these emissions and discharges are presented.

  14. Thermal management for high-capacity large format Li-ion batteries

    Science.gov (United States)

    Wang, Hsin; Kepler, Keith Douglas; Pannala, Sreekanth; Allu, Srikanth

    2017-05-30

    A lithium ion battery includes a cathode in electrical and thermal connection with a cathode current collector. The cathode current collector has an electrode tab. A separator is provided. An anode is in electrical and thermal connection with an anode current collector. The anode current collector has an electrode tab. At least one of the cathode current collector and the anode current collector comprises a thermal tab for heat transfer with the at least one current collector. The thermal tab is separated from the electrode tab. A method of operating a battery is also disclosed.

  15. A 3D thermal runaway propagation model for a large format lithium ion battery module

    International Nuclear Information System (INIS)

    Feng, Xuning; Lu, Languang; Ouyang, Minggao; Li, Jiangqiu; He, Xiangming

    2016-01-01

    In this paper, a 3D thermal runaway (TR) propagation model is built for a large format lithium ion battery module. The 3D TR propagation model is built based on the energy balance equation. Empirical equations are utilized to simplify the calculation of the chemical kinetics for TR, whereas equivalent thermal resistant layer is employed to simplify the heat transfer through the thin thermal layer. The 3D TR propagation model is validated by experiment and can provide beneficial discussions on the mechanisms of TR propagation. According to the modeling analysis of the 3D model, the TR propagation can be delayed or prevented through: 1) increasing the TR triggering temperature; 2) reducing the total electric energy released during TR; 3) enhancing the heat dissipation level; 4) adding extra thermal resistant layer between adjacent batteries. The TR propagation is successfully prevented in the model and validated by experiment. The model with 3D temperature distribution provides a beneficial tool for researchers to study the TR propagation mechanisms and for engineers to design a safer battery pack. - Highlights: • A 3D thermal runaway (TR) propagation model for Li-ion battery pack is built. • The 3D TR propagation model can fit experimental results well. • Temperature distributions during TR propagation are presented using the 3D model. • Modeling analysis provides solutions for the prevention of TR propagation. • Quantified solutions to prevent TR propagation in battery pack are discussed.

  16. Tracking groundwater discharge to a large river using tracers and geophysics.

    Science.gov (United States)

    Harrington, Glenn A; Gardner, W Payton; Munday, Tim J

    2014-01-01

    Few studies have investigated large reaches of rivers in which multiple sources of groundwater are responsible for maintaining baseflow. This paper builds upon previous work undertaken along the Fitzroy River, one of the largest perennial river systems in north-western Australia. Synoptic regional-scale sampling of both river water and groundwater for a suite of environmental tracers ((4) He, (87) Sr/(86) Sr, (222) Rn and major ions), and subsequent modeling of tracer behavior in the river, has enabled definition and quantification of groundwater input from at least three different sources. We show unambiguous evidence of both shallow "local" groundwater, possibly recharged to alluvial aquifers beneath the adjacent floodplain during recent high-flow events, and old "regional" groundwater introduced via artesian flow from deep confined aquifers. We also invoke hyporheic exchange and either bank return flow or parafluvial flow to account for background (222) Rn activities and anomalous chloride trends along river reaches where there is no evidence of the local or regional groundwater inputs. Vertical conductivity sections acquired through an airborne electromagnetic (AEM) survey provide insights to the architecture of the aquifers associated with these sources and general groundwater quality characteristics. These data indicate fresh groundwater from about 300 m below ground preferentially discharging to the river, at locations consistent with those inferred from tracer data. The results demonstrate how sampling rivers for multiple environmental tracers of different types-including stable and radioactive isotopes, dissolved gases and major ions-can significantly improve conceptualization of groundwater-surface water interaction processes, particularly when coupled with geophysical techniques in complex hydrogeological settings. © 2013, National Ground Water Association.

  17. Improving Hydrophobicity of Glass Surface Using Dielectric Barrier Discharge Treatment in Atmospheric Air

    International Nuclear Information System (INIS)

    Fang Zhi; Qiu Yuchang; Wang Hui; Kuffel, E

    2007-01-01

    Non-thermal plasmas under atmospheric pressure are of great interest in industrial applications, especially in material surface treatment. In this paper, the treatment of a glass surface for improving hydrophobicity using the non-thermal plasma generated by dielectric barrier discharge (DBD) at atmospheric pressure in ambient air is conducted, and the surface properties of the glass before and after the DBD treatment are studied by using contact angle measurement, surface resistance measurement and wet flashover voltage tests. The effects of the applied voltage and time duration of DBD on the surface modification are studied, and the optimal conditions for the treatment are obtained. It is found that a layer of hydrophobic coating is formed on the glass surface after spraying a thin layer of silicone oil and undergoing the DBD treatment, and the improvement of hydrophobicity depends on DBD voltage and treating time. It seems that there exists an optimum treating time for a certain applied voltage of DBD during the surface treatment. The test results of thermal aging and chemical aging show that the hydrophobic layer has quite stable characteristics. The interaction mechanism between the DBD plasma and the glass surface is discussed. It is concluded that CH 3 and large molecule radicals can react with the radicals in the glass surface to replace OH, and the hydrophobicity of the glass surface is improved accordingly

  18. Electro-thermal characterization of Lithium Iron Phosphate cell with equivalent circuit modeling

    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 studied the thermal response of the battery pack using UDDS and US06 test. • Active cooling system is needed to prolong life cycle of cell. - Abstract: Prediction of the battery performance is important in the development of the electric vehicles battery pack. A battery model that is capable to reproduce I–V characteristic, thermal response and predicting the state of charge of the battery will benefit the development of cell and reduce time to market for electric vehicles. In this work, an equivalent circuit model coupled with the thermal model is used to analyze the electrical and thermal behavior of Lithium Iron Phosphate pouch cell under various operating conditions. The battery model is comprised three RC blocks, one series resistor and one voltage source. The parameters of the battery model are extracted from pulse discharge curve under different temperatures. The simulations results of the battery model under constant current discharge and pulse charge and discharge show a good agreement with experimental data. The validated battery model is then extended to investigate the dynamic behavior of the electric vehicle battery pack using UDDS and US06 test cycle. The simulation results show that an active thermal management system is required to prolong the calendar life and ensure safety of the battery pack

  19. Numerical investigation of temperature distribution and thermal performance while charging-discharging thermal energy in aquifer

    NARCIS (Netherlands)

    Ganguly, S.; Mohan Kumar, M.S.; Date, Abhijit; Akbarzadeh, Aliakbar

    2017-01-01

    A three-dimensional (3D) coupled thermo-hydrogeological numerical model for a confined aquifer thermal energy storage (ATES) system underlain and overlain by rock media has been presented in this paper. The ATES system operates in cyclic mode. The model takes into account heat transport processes of

  20. Experimental investigation of the charge/discharge process for an organic PCM macroencapsulated in an aluminium rectangular cavity

    Science.gov (United States)

    Bejan, Andrei-Stelian; Labihi, Abdelouhab; Croitoru, Cristiana Verona; Catalina, Tiberiu; Chehouani, Hassan; Benhamou, Brahim

    2018-02-01

    Buildings sector has one of the highest potential regarding the reduction of greenhouse gases emissions, as being responsible for more than 40% of energy consumption worldwide. This is why, in order to achieve indoor thermal comfort, it is mandatory to use energy-efficient systems. Materials acting as thermal energy storage (TES) represents one of the most effective strategy that can be implemented and nowadays, many studies are focusing their attention on latent heat storage, respectively on phase changing materials (PCM) which can embed a large embed a high quantity of energy, unlike classic materials acting as thermal mass. This purpose of this paper is to experimentally investigate the charge and discharge processes for an organic PCM (RT35 paraffin) macroencapsulated in an aluminium rectangular cavity which was placed first in a horizontal position and after in a vertical position. After several experimental campaigns conducted we determined that the vertical position enhance the heat transfer because of the natural convection which occurs inside the cavity. Therefore, the charging time is lower in case of the vertical cavity and the temperature measured inside and on the surface is higher.

  1. Using Amines and Alkanes as Thermal-Runaway Retardants for Lithium-Ion Battery

    Science.gov (United States)

    Shi, Yang

    Thermal runaway imposes major challenges to large-scale lithium-ion batteries (LIBs). The working temperature of a LIB is usually around room temperature. However, upon mechanical abuse such as an impact or nail penetration, LIB cell components may fail and internal short circuits could be formed. As a result, a series of exothermic electrochemical reactions and decompositions would take place and the local temperature can rapidly increase. In this thesis, a few novel techniques are investigated to mitigate thermal runaway of LIBs. Mechanically triggered approach has been employed. Thermal-runaway retardant (TRR) is encapsulated in mechanically responsive packages made of materials inert to the battery environment, and upon external mechanical loadings the packages can be broken apart and release the TRR. This mechanism allows for the use of aggressive chemicals to suppress the short circuit discharge and reduce the subsequent exothermic phenomena, immediately after the battery is damaged even before temperature increase begins. The best TRR candidates are identified to be amines and alkanes. Among amines, secondary amines and tertiary amines perform better than primary amines. The reduction in electrolyte ionic conductivity and the displacement of electrolyte are the thermal-runaway-mitigation mechanisms of the secondary and the tertiary amines, respectively. Pentadecane is the best candidate among the alkanes under investigation, with the major working mechanism being electrolyte displacement. Impact tests on large pouch cells and high-energy battery chemistry were also performed; the results were quite encouraging.

  2. Discharge documentation of patients discharged to subacute facilities: a three-year quality improvement process across an integrated health care system.

    Science.gov (United States)

    Gandara, Esteban; Ungar, Jonathan; Lee, Jason; Chan-Macrae, Myrna; O'Malley, Terrence; Schnipper, Jeffrey L

    2010-06-01

    Effective communication among physicians during hospital discharge is critical to patient care. Partners Healthcare (Boston) has been engaged in a multi-year process to measure and improve the quality of documentation of all patients discharged from its five acute care hospitals to subacute facilities. Partners first engaged stakeholders to develop a consensus set of 12 required data elements for all discharges to subacute facilities. A measurement process was established and later refined. Quality improvement interventions were then initiated to address measured deficiencies and included education of physicians and nurses, improvements in information technology, creation of or improvements in discharge documentation templates, training of hospitalists to serve as role models, feedback to physicians and their service chiefs regarding reviewed cases, and case manager review of documentation before discharge. To measure improvement in quality as a result of these efforts, rates of simultaneous inclusion of all 12 applicable data elements ("defect-free rate") were analyzed over time. Some 3,101 discharge documentation packets of patients discharged to subacute facilities from January 1, 2006, through September 2008 were retrospectively studied. During the 11 monitored quarters, the defect-free rate increased from 65% to 96% (p improvements were seen in documentation of preadmission medication lists, allergies, follow-up, and warfarin information. Institution of rigorous measurement, feedback, and multidisciplinary, multimodal quality improvement processes improved the inclusion of data elements in discharge documentation required for safe hospital discharge across a large integrated health care system.

  3. Management optimization in Thermal complex through water reuse

    International Nuclear Information System (INIS)

    De Souza, S.; Manganelli, A.; Bertolotto, J.; Leys, P.; Garcia, B.

    2004-01-01

    Water reuse involves the concept of the exploitation of a previously used water, for a new, beneficial purpose. Actually, in Uruguay, thermal water is just utilised for balneological purposes, in this paper is proposed the water reuse taking the excess of used swimming pool water, and using it for heating and greenhouse irrigation, and australian lobster breeding. An important aspect of sustainable thermal water management is the protection of the exploted thermal water resources, so water reuse plays an important role in water resource, and ecosystem management, because it reduces the volume discharged and also reduces the risk of thermal pollution [es

  4. Response of lead-acid batteries to chopper-controlled discharge: Preliminary results

    Science.gov (United States)

    Cataldo, R. L.

    1978-01-01

    The preliminary results of simulated electric vehicle, chopper, speed controller discharge of a battery show energy output losses up to 25 percent compared to constant current discharges at the same average discharge current of 100 amperes. These energy losses are manifested as temperature rises during discharge, amounting to a two-fold increase for a 400-ampere pulse compared to the constant current case. Because of the potentially large energy inefficiency, the results suggest that electric vehicle battery/speed controller interaction must be carefully considered in vehicle design.

  5. The Effect of Flow Distribution on the Concentration of NO Produced by Pulsed Arc Discharge

    International Nuclear Information System (INIS)

    Hu Hui; Bao Bin; Wang Heli; Liang Haiyan; He Junjia; He Zhenghao; Li Jin

    2007-01-01

    As a new method to cure acute respiratory distress syndrome (ARDS), high blood pressure and some illnesses related to the lung, NO has recently received more attention. Thermal plasmas produced by arc discharge can create medical NO, but the concentration of NO 2 produced by arc discharge must be controlled simultaneously. This paper investigates the characteristics and regulations of NO production at different flow distribution by pulsed arc discharge in dry air with a special pulsed power. The experimental results show that the flow distribution has a considerable effect on the NO concentration, the stabilization of NO. The production of NO 2 could be controlled and the ratio of NO 2 /NO was decreased to about 10% in the arc discharge. Therefore, the arc discharge could produce stable inhaled NO for medical treatment by changing the flow distribution

  6. High pressure microwave discharge for electrodeless Xe-lamp

    International Nuclear Information System (INIS)

    Kudela, J.; Kando, M.

    1998-01-01

    Preliminary results are presented of the investigation into the high pressure Xe microwave discharge in bent tubes, sustained by electromagnetic surface wave. The research was aimed to help with the design of a new generation of high intensity light sources with generally more complex shapes than those commonly used. The results show that the electromagnetic surface wave can effectively sustain discharge in tubes with various bending radii within the large pressure range. The curved shapes of discharge tubes improve the cooling of the lamp which is one of the major technological difficulties. It was shown that under relatively lower powers and higher gas pressures (100 Torr) the discharge exhibits a streamer-like filamentation and the branching of filaments. The phenomena of the effective sustaining of the discharge by surface wave propagation along curved plasma columns will be investigated in more detail by measurements of the profiles of surface wave electric and magnetic field intensities. (author)

  7. Numerical study on xenon positive column discharges of mercury-free lamp

    International Nuclear Information System (INIS)

    Ouyang, Jiting; He, Feng; Miao, Jinsong; Wang, Jianqi; Hu, Wenbo

    2007-01-01

    In this paper, the numerical study has been performed on the xenon positive column discharges of mercury-free fluorescent lamp. The plasma discharge characteristics are analyzed by numerical simulation based on two-dimensional fluid model. The effects of cell geometry, such as the dielectric layer, the electrode width, the electrode gap, and the cell height, and the filling gas including the pressure and the xenon percentage are investigated in terms of discharge current and discharge efficiency. The results show that a long transient positive column will form in the xenon lamp when applying ac sinusoidal power and the lamp can operate in a large range of voltage and frequency. The front dielectric layer of the cell plays an important role in the xenon lamp while the back layer has little effect. The ratio of electrode gap to cell height should be large to achieve a long positive column xenon lamp and higher efficiency. Increase of pressure or xenon concentration results in an increase of discharge efficiency and voltage. The discussions will be helpful for the design of commercial xenon lamp cells

  8. Plasma Discharge Process in a Pulsed Diaphragm Discharge System

    Science.gov (United States)

    Duan, Jianjin; Hu, Jue; Zhang, Chao; Wen, Yuanbin; Meng, Yuedong; Zhang, Chengxu

    2014-12-01

    As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages: (1) Joule heating and heat exchange stage; (2) nucleated site formation; (3) plasma generation (initiation of the breakdown stage); (4) avalanche growth and plasma expansion; (5) plasma contraction; (6) termination of the plasma discharge; and (7) heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.

  9. Ionization in atmospheres of brown dwarfs and extrasolar planets VI: Properties of large-scale discharge events

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, R. L.; Helling, Ch.; Hodosán, G.; Bilger, C.; Stark, C. R., E-mail: ch@leap2010.eu [SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2014-03-20

    Mineral clouds in substellar atmospheres play a special role as a catalyst for a variety of charge processes. If clouds are charged, the surrounding environment becomes electrically activated, and ensembles of charged grains are electrically discharging (e.g., by lightning), which significantly influences the local chemistry creating conditions similar to those thought responsible for life in early planetary atmospheres. We note that such lightning discharges contribute also to the ionization state of the atmosphere. We apply scaling laws for electrical discharge processes from laboratory measurements and numerical experiments to DRIFT-PHOENIX model atmosphere results to model the discharge's propagation downward (as lightning) and upward (as sprites) through the atmospheric clouds. We evaluate the spatial extent and energetics of lightning discharges. The atmospheric volume affected (e.g., by increase of temperature or electron number) is larger in a brown dwarf atmosphere (10{sup 8}-10{sup 10} m{sup 3}) than in a giant gas planet (10{sup 4}-10{sup 6} m{sup 3}). Our results suggest that the total dissipated energy in one event is <10{sup 12} J for all models of initial solar metallicity. First attempts to show the influence of lightning on the local gas phase indicate an increase of small carbohydrate molecules like CH and CH{sub 2} at the expense of CO and CH{sub 4}. Dust-forming molecules are destroyed and the cloud particle properties are frozen in unless enough time is available for complete evaporation. We summarize instruments potentially suitable to observe lightning on extrasolar objects.

  10. Influence Voltage Pulse Electrical Discharge In The Water at the Endurance Fatigue Of Carbon Steel

    OpenAIRE

    I.A. Vakulenko; A.G. Lisnyak

    2016-01-01

    Effect of pulses of electrical discharge in the water at the magnitude of the limited endurance under cyclic loading thermally hardened carbon steel was investigated. Observed increase stamina during cyclic loading a corresponding increase in the number of accumulated dislocations on the fracture surface. Using the equation of Cofino-Manson has revealed a decrease of strain loading cycle after treatment discharges. For field-cycle fatigue as a result of processing the voltage pulses carbon st...

  11. Design of a 10 MJ fast discharging homopolar machine

    International Nuclear Information System (INIS)

    Stillwagon, R.E.; Thullen, P.

    1977-01-01

    The design of a fast discharging homopolar machine is described. The machine capacity is 10 MJ with a 30 ms energy delivery time. The salient features of the machine are relatively high terminal voltage, fast discharge time, high power density and high efficiency. The machine integrates several new technologies including high surface speeds, large superconducting magnets and current collection at high density

  12. Marine pastures: a by-product of large (100 megawatt or larger) floating ocean-thermal power plants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, S.; Roels, O.A.

    1976-08-31

    The potential biological productivity of an open-sea mariculture system utilizing the deep-sea water discharged from an ocean-thermal energy conversion (OTEC) plant was investigated. In a series of land-based studies, surface water was used to inoculate deep water and the primary production of the resultant blooms was investigated. Each cubic meter of deep water can produce approximately 2.34 g of phytoplankton protein, and that an OTEC plant discharging deep water at a rate of 4.5 x 10/sup 4/ m/sup 3/ min/sup -1/ could produce 5.3 x 10/sup 7/ kg of phytoplankton protein per 350-day year. A series of land-based shellfish studies indicated that, when fed at a constant rate of 1.83 x 10/sup -3/ g of protein per second per 70-140 g of whole wet weight, the clam, Tapes japonica, could convert the phytoplankton protein-nitrogen into shellfish meat protein-nitrogen with an efficiency of about 33 per cent. Total potential wet meat weight production from an OTEC plant pumping 4.5 x 10/sup 4/ m/sup 3/ min/sup -1/ is approximately 4.14 x 10/sup 8/ kg for a 350-day year. Various factors affecting the feasibility of open-sea mariculture are discussed. It is recommended that future work concentrate on a technical and economic analysis. (WDM)

  13. Velocity persistence of Brownian particles generated in a glow discharge

    International Nuclear Information System (INIS)

    Hurd, A.J.; Ho, P.

    1989-01-01

    Quasielastic light scattering from Brownian particles in the rarefied environment of a glow discharge exhibits Gaussianlike intensity correlation functions owing to the long mean free paths of the particles. The shape of the correlation function depends on the particles' average thermal velocity and friction coefficient, which can be related to aggregate mass and structure, and indicates a crossover from kinetic to hydrodynamic behavior

  14. Double discharges in unipolar-pulsed dielectric barrier discharge xenon excimer lamps

    International Nuclear Information System (INIS)

    Liu Shuhai; Neiger, Manfred

    2003-01-01

    Excitation of dielectric barrier discharge xenon excimer lamps by unipolar short square pulses is studied in this paper. Two discharges with different polarity are excited by each voltage pulse (double discharge phenomenon). The primary discharge occurs at the top or at the rising flank of the applied unipolar square pulse, which is directly energized by the external circuit. The secondary discharge with the reversed polarity occurs at the falling flank or shortly after the falling flank end (zero external voltage) depending on the pulse width, which is energized by the energy stored by memory charges deposited by the primary discharge. Fast-speed ICCD imaging shows the primary discharge has a conic discharge appearance with a channel broadening on the anode side. This channel broadening increases with increasing the pulse top level. Only the anode-side surface discharge is observed in the primary discharge. The surface discharge on the cathode side which is present in bipolar sine voltage excitation is not observed. On the contrary, the secondary discharge has only the cathode-side surface discharge. The surface discharge on the anode side is not observed. The secondary discharge is much more diffuse than the primary discharge. Time-resolved emission measurement of double discharges show the secondary discharge emits more VUV xenon excimer radiation but less infrared (IR) xenon atomic emission than the primary discharge. It was found that the IR xenon atomic emission from the secondary discharge can be reduced by shortening the pulse width. The energy efficiency of unipolar-pulsed xenon excimer lamps (the overall energy efficiency of double discharges) is much higher than that obtained under bipolar sine wave excitation. The output VUV spectrum under unipolar pulse excitation is found to be identical to that under sine wave excitation and independent of injected electric power

  15. Thermal responses of marine animals with reference to Kalpakkam Coast (South East Coast of India)

    International Nuclear Information System (INIS)

    Shahul Hameed, P.; Syed Mohamed, H.E.; Krishnamoorthy, R.

    2008-01-01

    Kalpakkam has been chosen as model coastal site to study the impact of thermal discharges on water qualities, benthic animals and fishes. The results of this study are expected to be valid for any given open coastal location on the east and west coast of India. The present study investigates, the impact of the elevated temperature due to thermal discharge on two groups of marine animals viz. Benthos (non-swimming bottom dwellers) and fishes

  16. A study on the characteristics of the decay heat removal capacity for a large thermal rated LMR design

    International Nuclear Information System (INIS)

    Uh, J. H.; Kim, E. K.; Kim, S. O.

    2003-01-01

    The design characteristics and the decay heat removal capacity according to the type of DHR (Decay Heat Removal) system in LMR are quantitatively analyzed, and the general relationship between the rated core thermal power and decay heat removal capacity is created in this study. Based on these analyses results, a feasibility of designing a larger thermal rating KALIMER plant is investigated in view of decay heat removal capacity, and DRC (Direct Reactor Cooling) type DHR system which rejects heat from the reactor pool to air is proper to satisfy the decay heat removal capacity for a large thermal rating plant above 1,000 MWth. Some defects, however, including the heat loss under normal plant operation and the lack of reliance associated with system operation should be resolved in order to adopt the total passive concept. Therefore, the new concept of DHR system for a larger thermal rating KALIMER design, named as PDRC (passive decay heat removal circuit), is established in this study. In the newly established concept of PDRC, the Na-Na heat exchanger is located above the sodium cold pool and is prevented from the direct sodium contact during normal operation. This total passive feature has the superiority in the aspect of the minimizing the normal heat loss and the increasing the operation reliance of DHR system by removing either any operator action or any external operation signal associated with system operation. From this study, it is confirmed that the new concept of PDRC is useful to the designing of a large thermal rating power plant of KALIMER-600 in view of decay heat removal capability

  17. Physical and chemical properties of SSM-discharge in the system gas-liquid

    International Nuclear Information System (INIS)

    Chernyak, V.Ya.; Olszewski, S.V.; Evstigneev, M.A.; Tsybulev, P.N.; Voronin, P.N.

    1996-01-01

    Investigation on the influence of solved Na 2 SO 4 and NaOH concentrations on discharge plasma contacting solution, and on the influence of discharge parameters on metal precipitation speed, as well as chemical analysis of precipitant in the system plasma - water solution were performed. After plasma treatment of water solutions of Zn and Al nitrates flake-like and snow-white precipitations appear. Differential thermal and atom-adsorption analysis of precipitations show that metals precipitate as hydroxides. Investigation of the influence of SSM-discharge polarity on plasma-chemical precipitation efficiency show that positive polarity of liquid electrode is more preferable. Probably, this fact takes place because plasma electrode of the second subsystem is the cathode, and thus reactions of cations (metal ions) are more intensive near it. (authors)

  18. Estimating Discharge in Low-Order Rivers With High-Resolution Aerial Imagery

    Science.gov (United States)

    King, Tyler V.; Neilson, Bethany T.; Rasmussen, Mitchell T.

    2018-02-01

    Remote sensing of river discharge promises to augment in situ gauging stations, but the majority of research in this field focuses on large rivers (>50 m wide). We present a method for estimating volumetric river discharge in low-order (standard deviation of 6%). Sensitivity analyses were conducted to determine the influence of inundated channel bathymetry and roughness parameters on estimated discharge. Comparison of synthetic rating curves produced through sensitivity analyses show that reasonable ranges of parameter values result in mean percent errors in predicted discharges of 12%-27%.

  19. Method and apparatus for debris mitigation for an electrical discharge source

    Science.gov (United States)

    Klebanoff, Leonard E [San Clemente, CA; Rader, Daniel J [Albuquerque, NM; Silfvast, William T [Helena, CA

    2006-01-24

    Method and apparatus for mitigating the transport of debris generated and dispersed from electric discharge sources by thermophoretic and electrostatic deposition. A member is positioned adjacent the front electrode of an electric discharge source and used to establish a temperature difference between it and the front electrode. By flowing a gas between the member and the front electrode a temperature gradient is established that can be used for thermophoretic deposition of particulate debris on either the member or front electrode depending upon the direction of the thermal gradient. Establishing an electric field between the member and front electrode can aid in particle deposition by electrostatic deposition.

  20. Metod And Apparatus For Debris Mitigation For An Electrical Discharge Source

    Science.gov (United States)

    Klebanoff, Leonard E.; Silfvast, William T.; Rader, Daniel J.

    2005-05-03

    Method and apparatus for mitigating the transport of debris generated and dispersed from electric discharge sources by thermophoretic and electrostatic deposition. A member is positioned adjacent the front electrode of an electric discharge source and used to establish a temperature difference between it and the front electrode. By flowing a gas between the member and the front electrode a temperature gradient is established that can be used for thermophoretic deposition of particulate debris on either the member or front electrode depending upon the direction of the thermal gradient. Establishing an electric field between the member and front electrode can aid in particle deposition by electrostatic deposition.

  1. Treatment time reduction for large thermal lesions by using a multiple 1D ultrasound phased array system

    International Nuclear Information System (INIS)

    Liu, H.-L.; Chen, Y.-Y.; Yen, J.-Y.; Lin, W.-L.

    2003-01-01

    To generate large thermal lesions in ultrasound thermal therapy, cooling intermissions are usually introduced during the treatment to prevent near-field heating, which leads to a long treatment time. A possible strategy to shorten the total treatment time is to eliminate the cooling intermissions. In this study, the two methods, power optimization and acoustic window enlargement, for reducing power accumulation in the near field are combined to investigate the feasibility of continuously heating a large target region (maximally 3.2 x 3.2 x 3.2 cm 3 ). A multiple 1D ultrasound phased array system generates the foci to scan the target region. Simulations show that the target region can be successfully heated without cooling and no near-field heating occurs. Moreover, due to the fact that there is no cooling time during the heating sessions, the total treatment time is significantly reduced to only several minutes, compared to the existing several hours

  2. A mathematical model for surface roughness of fluidic channels produced by grinding aided electrochemical discharge machining (G-ECDM

    Directory of Open Access Journals (Sweden)

    Ladeesh V. G.

    2017-01-01

    Full Text Available Grinding aided electrochemical discharge machining is a hybrid technique, which combines the grinding action of an abrasive tool and thermal effects of electrochemical discharges to remove material from the workpiece for producing complex contours. The present study focuses on developing fluidic channels on borosilicate glass using G-ECDM and attempts to develop a mathematical model for surface roughness of the machined channel. Preliminary experiments are conducted to study the effect of machining parameters on surface roughness. Voltage, duty factor, frequency and tool feed rate are identified as the significant factors for controlling surface roughness of the channels produced by G-ECDM. A mathematical model was developed for surface roughness by considering the grinding action and thermal effects of electrochemical discharges in material removal. Experiments are conducted to validate the model and the results obtained are in good agreement with that predicted by the model.

  3. Chromium–niobium co-doped vanadium dioxide films: Large temperature coefficient of resistance and practically no thermal hysteresis of the metal–insulator transition

    Directory of Open Access Journals (Sweden)

    Kenichi Miyazaki

    2016-05-01

    Full Text Available We investigated the effects of chromium (Cr and niobium (Nb co-doping on the temperature coefficient of resistance (TCR and the thermal hysteresis of the metal–insulator transition of vanadium dioxide (VO2 films. We determined the TCR and thermal-hysteresis-width diagram of the V1−x−yCrxNbyO2 films by electrical-transport measurements and we found that the doping conditions x ≳ y and x + y ≥ 0.1 are appropriate for simultaneously realizing a large TCR value and an absence of thermal hysteresis in the films. By using these findings, we developed a V0.90Cr0.06Nb0.04O2 film grown on a TiO2-buffered SiO2/Si substrate that showed practically no thermal hysteresis while retaining a large TCR of 11.9%/K. This study has potential applications in the development of VO2-based uncooled bolometers.

  4. Environmentally-induced discharge transient coupling to spacecraft

    Science.gov (United States)

    Viswanathan, R.; Barbay, G.; Stevens, N. J.

    1985-01-01

    The Hughes SCREENS (Space Craft Response to Environments of Space) technique was applied to generic spin and 3-axis stabilized spacecraft models. It involved the NASCAP modeling for surface charging and lumped element modeling for transients coupling into a spacecraft. A differential voltage between antenna and spun shelf of approx. 400 V and current of 12 A resulted from discharge at antenna for the spinner and approx. 3 kv and 0.3 A from a discharge at solar panels for the 3-axis stabilized Spacecraft. A typical interface circuit response was analyzed to show that the transients would couple into the Spacecraft System through ground points, which are most vulnerable. A compilation and review was performed on 15 years of available data from electron and ion current collection phenomena. Empirical models were developed to match data and compared with flight data of Pix-1 and Pix-2 mission. It was found that large space power systems would float negative and discharge if operated at or above 300 V. Several recommendations are given to improve the models and to apply them to large space systems.

  5. 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

  6. The stress analysis evaluation and pipe support layout for pressurizer discharge system

    International Nuclear Information System (INIS)

    Mao Qing; Wang Wei; Zhang Yixiong

    2000-01-01

    The author presents the stress analysis and evaluation of pipe layout and support adjustment process for Qinshan phase II pressurizer discharge system. Using PDL-SYSPIPE INTERFACE software, the characteristic parameters of the system are gained from 3-D CAD engineering design software PDL and outputted as the input date file format of special pipe stress analysis program SYSPIPE. Based on that, SYSPIPE program fast stress analysis function is applied in adjusting pipe layout , support layout and support types. According to RCC-M standard, the pipe stress analysis and evaluation under deadweight, internal pressure, thermal expansion, seismic, pipe rupture and discharge loads are fulfilled

  7. Application of the model of the relativistic anti-loss-cone distribution to ECE spectrum in discharge applying LH wave

    International Nuclear Information System (INIS)

    Sato, Masayasu; Yokomizo, Hideaki

    1987-11-01

    The electron cyclotron emission (ECE) is dominated from supra-thermal electron in discharge applying LH wave. We obtain informations of supra-thermal electron by applying the model of the relativistic anti-loss-cone distribution to ECE spectrum in the discharge. In this model, the emission perpendicular to the magnetic field are considered. The frequency range is considered to be well above the plasma and electron cyclotron frequencies, thus collective effects can be neglected. The electron distribution is assumed to be anisotropic in the velocity space and strongly extended in the direction parallel to the magnetic field, namely the relativistic anti-loss-cone distribution. The informations of supra-thermal electron are obtained by the following way. The temperature and density of the supra-thermal electron and the anti-loss-cone angle are obtained from the power spectrum of LH wave launched, the measured slope of the spectrum of ECE and the spectral radiance of ECE. (author)

  8. Thermal Stability of Ultrafine Grained Pure Copper Prepared by Large Strain Extrusion Machining

    Directory of Open Access Journals (Sweden)

    Bangxian Wu

    2018-05-01

    Full Text Available Ultrafine grained (UFG pure copper chips with improved material strength have been successfully prepared by large strain extrusion machining (LSEM. However, the thermal stability of the UFG chips has been a key characteristic that has restricted their use in practical applications. To understand the influence of annealing temperature and annealing time on their microstructures and mechanical properties, the UFG chips were subjected to isochronous and isothermal annealing treatments as well as Vickers hardness tests in the present study. From the results, we found that the UFG chips maintain high hardness when annealing at temperatures up to 160 °C but begin to exhibit a reduction in their hardness while the annealing temperature reached above 200 °C. When annealed at 280 °C for 10–240 min, the grain size increased slightly and reached a stable value of 2 µm with an increase in annealing time and with a decrease in the hardness of the chips. These results indicated that UFG pure copper chips have good thermal stability at temperatures below 160 °C.

  9. Improving discharge data fidelity for use in large administrative databases.

    Science.gov (United States)

    Gologorsky, Yakov; Knightly, John J; Lu, Yi; Chi, John H; Groff, Michael W

    2014-06-01

    Large administrative databases have assumed a major role in population-based studies examining health care delivery. Lumbar fusion surgeries specifically have been scrutinized for rising rates coupled with ill-defined indications for fusion such as stenosis and spondylosis. Administrative databases classify cases with the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). The ICD-9-CM discharge codes are not designated by surgeons, but rather are assigned by trained hospital medical coders. It is unclear how accurately they capture the surgeon's indication for fusion. The authors first sought to compare the ICD-9-CM code(s) assigned by the medical coder according to the surgeon's indication based on a review of the medical chart, and then to elucidate barriers to data fidelity. A retrospective review was undertaken of all lumbar fusions performed in the Department of Neurosurgery at the authors' institution between August 1, 2011, and August 31, 2013. Based on this review, the indication for fusion in each case was categorized as follows: spondylolisthesis, deformity, tumor, infection, nonpathological fracture, pseudarthrosis, adjacent-level degeneration, stenosis, degenerative disc disease, or disc herniation. These surgeon diagnoses were compared with the primary ICD-9-CM codes that were generated by the medical coders and submitted to administrative databases. A follow-up interview with the hospital's coders and coding manager was undertaken to review causes of error and suggestions for future improvement in data fidelity. There were 178 lumbar fusion operations performed in the course of 170 hospital admissions. There were 44 hospitalizations in which fusion was performed for tumor, infection, or nonpathological fracture. Of these, the primary diagnosis matched the surgical indication for fusion in 98% of cases. The remaining 126 hospitalizations were for degenerative diseases, and of these, the primary ICD-9-CM

  10. Auxiliary System Load Schemes in Large Thermal and Nuclear Power Plants

    International Nuclear Information System (INIS)

    Kuzle, I.; Bosnjak, D.; Pandzic, H.

    2010-01-01

    Uninterrupted auxiliary system power supply in large power plants is a key factor for normal operation, transient states, start-ups and shutdowns and particularly during fault conditions. Therefore, there are many challenges in designing the main electrical system as well as the auxiliary systems power supply. Depending upon the type of fuel used and the environmental control system required, a thermal power plant may consume as much as 10% of its total generation for auxiliary power, while a nuclear power plant may require only 4 - 6% auxiliaries. In general, the larger the power generating plant, the higher the voltage selected for the AC auxiliary electric system. Most stations in the 75 to 500 MW range utilize 4,2 kV as the base auxiliary system voltage. Large generating stations 500 - 1000 MW and more use voltage levels of 6,9 kV and more. Some single dedicated loads such as electric driven boiler feed pumps are supplied ba a 13,8 kV bus. While designing the auxiliary electric system, the following areas must be considered: motor starting requirements, voltage regulation requirements, short-circuit duty requirements, economic considerations, reliability and alternate sources. Auxiliary power supply can't be completely generalized and each situation should be studied on its own merits to determine the optimal solution. Naturally, nuclear power plants have more reliability requirements and safety design criteria. Main coolant-pump power supply and continuity of service to other vital loads deserve special attention. This paper presents an overview of some up-to-date power plant auxiliary load system concepts. The main types of auxiliary loads are described and the electric diagrams of the modern auxiliary system supply concepts are given. Various alternative sources of auxiliary electrical supply are considered, the advantages and disadvantages of these are compared and proposals are made for high voltage distribution systems around the thermal and nuclear plant

  11. Observations of nearshore groundwater discharge: Kahekili Beach Park submarine springs, Maui, Hawaii

    Science.gov (United States)

    Swarzenski, Peter W.; Dulai, H.; Kroeger, K.D.; Smith, C.G.; Dimova, N.; Storlazzi, C. D.; Prouty, N.G.; Gingerich, S.B.; Glenn, C. R.

    2016-01-01

    Study regionThe study region encompasses the nearshore, coastal waters off west Maui, Hawaii. Here abundant groundwater—that carries with it a strong land-based fingerprint—discharges into the coastal waters and over a coral reef.Study focusCoastal groundwater discharge is a ubiquitous hydrologic feature that has been shown to impact nearshore ecosystems and material budgets. A unique combined geochemical tracer and oceanographic time-series study addressed rates and oceanic forcings of submarine groundwater discharge at a submarine spring site off west Maui, Hawaii.New hydrological insights for the regionEstimates of submarine groundwater discharge were derived for a primary vent site and surrounding coastal waters off west Maui, Hawaii using an excess 222Rn (t1/2 = 3.8 d) mass balance model. Such estimates were complemented with a novel thoron (220Rn,t1/2 = 56 s) groundwater discharge tracer application, as well as oceanographic time series and thermal infrared imagery analyses. In combination, this suite of techniques provides new insight into the connectivity of the coastal aquifer with the near-shore ocean and examines the physical drivers of submarine groundwater discharge. Lastly, submarine groundwater discharge derived constituent concentrations were tabulated and compared to surrounding seawater concentrations. Such work has implications for the management of coastal aquifers and downstream nearshore ecosystems that respond to sustained constituent loadings via this submarine route.

  12. Hazardous gas treatment using atmospheric pressure microwave discharges

    International Nuclear Information System (INIS)

    Mizeraczyk, Jerzy; Jasinski, Mariusz; Zakrzewski, Zenon

    2005-01-01

    Atmospheric pressure microwave discharge methods and devices used for producing non-thermal plasmas for control of gaseous pollutants are described in this paper. The main part of the paper is concerned with microwave torch discharges (MTDs). Results of laboratory experiments on plasma abatement of several volatile organic compounds (VOCs) in their mixtures with either synthetic air or nitrogen in low (∼100 W) and moderate (200-400 W) microwave torch plasmas at atmospheric pressure are presented. Three types of MTD generators, i.e. low-power coaxial-line-based MTDs, moderate-power waveguide-based coaxial-line MTDs and moderate-power waveguide-based MTDs were used. The gas flow rate and microwave (2.45 GHz) power delivered to the discharge were in the range of 1-3 litre min -1 and 100-400 W, respectively. The concentrations of the processed gaseous pollutants were from several to several tens of per cent. The results showed that the MTD plasmas fully decomposed the VOCs at a relatively low energy cost. The energy efficiency of decomposition of several gaseous pollutants reached 1000 g (kW-h) -1 . This suggests that MTD plasmas can be useful tools for decomposition of highly concentrated VOCs

  13. Experimental Investigation on the Characteristics of Sliding Discharge Plasma Aerodynamic Actuation

    International Nuclear Information System (INIS)

    Song Huimin; Zhang Qiaogen; Li Yinghong; Jia Min; Wu Yun

    2011-01-01

    A new electrical discharge called sliding discharge was developed to generate plasma aerodynamic actuation for flow control. A microsecond-pulse high voltage with a DC component was used to energize a three-electrode actuator to generate sliding discharge. The characteristics of plasma aerodynamic actuation by sliding discharge were experimentally investigated. Discharge morphology shows that sliding discharge is formed when energized by properly adjusting microsecond-pulse and DC voltage. Compared to dielectric barrier discharge (DBD), the plasma extension of sliding discharge is quasi-diffusive and stable but longer and more intensive. Results from particle image velocimetry (PIV) test indicate that plasma aerodynamic actuation by sliding discharge can induce a ‘starting vortex’ and a quasi-steady ‘near-wall jet’. Body force induced by plasma aerodynamic actuation is about the order of mN, which is stronger than that induced by single DBD. It is inferred that microsecond-pulse sliding discharge may be more effective to generate large-scale plasma aerodynamic actuation, which is very promising for improving aircraft aerodynamic characteristics and propulsion efficiency.

  14. Experimental Investigation on the Characteristics of Sliding Discharge Plasma Aerodynamic Actuation

    Science.gov (United States)

    Song, Huimin; Li, Yinghong; Zhang, Qiaogen; Jia, Min; Wu, Yun

    2011-10-01

    A new electrical discharge called sliding discharge was developed to generate plasma aerodynamic actuation for flow control. A microsecond-pulse high voltage with a DC component was used to energize a three-electrode actuator to generate sliding discharge. The characteristics of plasma aerodynamic actuation by sliding discharge were experimentally investigated. Discharge morphology shows that sliding discharge is formed when energized by properly adjusting microsecond-pulse and DC voltage. Compared to dielectric barrier discharge (DBD), the plasma extension of sliding discharge is quasi-diffusive and stable but longer and more intensive. Results from particle image velocimetry (PIV) test indicate that plasma aerodynamic actuation by sliding discharge can induce a ‘starting vortex’ and a quasi-steady ‘near-wall jet’. Body force induced by plasma aerodynamic actuation is about the order of mN, which is stronger than that induced by single DBD. It is inferred that microsecond-pulse sliding discharge may be more effective to generate large-scale plasma aerodynamic actuation, which is very promising for improving aircraft aerodynamic characteristics and propulsion efficiency.

  15. Ti(r) profiles from the JET neutron profile monitor for ohmic discharges

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, B. (ENEA, Frascati (Italy). Centro Ricerche Energia); Marcus, F.B.; Conroy, S.; Jarvis, O.N.; Loughlin, M.J.; Sadler, G.; Belle, P. van (Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking); Adams, J.M.; Watkins, N. (AEA Industrial Technology, Harwell (United Kingdom))

    1991-01-01

    A study has been made of the neutron emissivity, using the JET neutron profile monitor, obtained for ohmically heated deuterium discharges. Both one-dimensional (1-D) best-fit inversion procedures and 2-D tomography have been used to deduce the radial profile of the neutron emission from the line-integral data. The profiles of ion temperature and ion thermal conductivity are then derived. The scaling of the ion thermal conductivity with plasma current is found to be opposite to that of neoclassical theory. (author) 4 refs., 5 figs.

  16. Ultrahigh lattice thermal conductivity in topological semimetal TaN caused by a large acoustic-optical gap.

    Science.gov (United States)

    Guo, San-Dong; Liu, Bang-Gui

    2018-03-14

    Topological semimetals may have potential applications such as in topological qubits, spintronics and quantum computations. Efficient heat dissipation is a key factor for the reliability and stability of topological semimetal-based nano-electronics devices, which is closely related to high thermal conductivity. In this work, the elastic properties and lattice thermal conductivity of TaN are investigated using first-principles calculations and the linearized phonon Boltzmann equation within the single-mode relaxation time approximation. According to the calculated bulk modulus, shear modulus and C 44 , TaN can be regarded as a potential incompressible and hard material. The room-temperature lattice thermal conductivity is predicted to be 838.62 [Formula: see text] along the a axis and 1080.40 [Formula: see text] along the c axis, showing very strong anisotropy. It is found that the lattice thermal conductivity of TaN is several tens of times higher than other topological semimetals, such as TaAs, MoP and ZrTe, which is due to the very longer phonon lifetimes for TaN than other topological semimetals. The very different atomic masses of Ta and N atoms lead to a very large acoustic-optical band gap, and then prohibit the scattering between acoustic and optical phonon modes, which gives rise to very long phonon lifetimes. Calculated results show that isotope scattering has little effect on lattice thermal conductivity, and that phonons with mean free paths larger than 20 (80) [Formula: see text] along the c direction at 300 K have little contribution to the total lattice thermal conductivity. This work implies that TaN-based nano-electronics devices may be more stable and reliable due to efficient heat dissipation, and motivates further experimental works to study lattice thermal conductivity of TaN.

  17. Ultrahigh lattice thermal conductivity in topological semimetal TaN caused by a large acoustic-optical gap

    Science.gov (United States)

    Guo, San-Dong; Liu, Bang-Gui

    2018-03-01

    Topological semimetals may have potential applications such as in topological qubits, spintronics and quantum computations. Efficient heat dissipation is a key factor for the reliability and stability of topological semimetal-based nano-electronics devices, which is closely related to high thermal conductivity. In this work, the elastic properties and lattice thermal conductivity of TaN are investigated using first-principles calculations and the linearized phonon Boltzmann equation within the single-mode relaxation time approximation. According to the calculated bulk modulus, shear modulus and C 44, TaN can be regarded as a potential incompressible and hard material. The room-temperature lattice thermal conductivity is predicted to be 838.62 W~m-1~K^{-1} along the a axis and 1080.40 W~m-1~K^{-1} along the c axis, showing very strong anisotropy. It is found that the lattice thermal conductivity of TaN is several tens of times higher than other topological semimetals, such as TaAs, MoP and ZrTe, which is due to the very longer phonon lifetimes for TaN than other topological semimetals. The very different atomic masses of Ta and N atoms lead to a very large acoustic-optical band gap, and then prohibit the scattering between acoustic and optical phonon modes, which gives rise to very long phonon lifetimes. Calculated results show that isotope scattering has little effect on lattice thermal conductivity, and that phonons with mean free paths larger than 20 (80) μm along the c direction at 300 K have little contribution to the total lattice thermal conductivity. This work implies that TaN-based nano-electronics devices may be more stable and reliable due to efficient heat dissipation, and motivates further experimental works to study lattice thermal conductivity of TaN.

  18. Computational Study of Anomalous Transport in High Beta DIII-D Discharges with ITBs

    Science.gov (United States)

    Pankin, Alexei; Garofalo, Andrea; Grierson, Brian; Kritz, Arnold; Rafiq, Tariq

    2015-11-01

    The advanced tokamak scenarios require a large bootstrap current fraction and high β. These large values are often outside the range that occurs in ``conventional'' tokamak discharges. The GLF23, TGLF, and MMM transport models have been previously validated for discharges with parameters associated with ``conventional'' tokamak discharges. It has been demonstrated that the TGLF model under-predicts anomalous transport in high β DIII-D discharges [A.M. Garofalo et al. 2015 TTF Workshop]. In this research, the validity of MMM7.1 model [T. Rafiq et al. Phys. Plasmas 20 032506 (2013)] is tested for high β DIII-D discharges with low and high torque. In addition, the sensitivity of the anomalous transport to β is examined. It is shown that the MMM7.1 model over-predicts the anomalous transport in the DIII-D discharge 154406. In particular, a significant level of anomalous transport is found just outside the internal transport barrier. Differences in the anomalous transport predicted using TGLF and MMM7.1 are reviewed. Mechanisms for quenching of anomalous transport in the ITB regions of high-beta discharges are investigated. This research is supported by US Department of Energy.

  19. Thermal Deformation and RF Performance Analyses for the SWOT Large Deployable Ka-Band Reflectarray

    Science.gov (United States)

    Fang, H.; Sunada, E.; Chaubell, J.; Esteban-Fernandez, D.; Thomson, M.; Nicaise, F.

    2010-01-01

    A large deployable antenna technology for the NASA Surface Water and Ocean Topography (SWOT) Mission is currently being developed by JPL in response to NRC Earth Science Tier 2 Decadal Survey recommendations. This technology is required to enable the SWOT mission due to the fact that no currently available antenna is capable of meeting SWOT's demanding Ka-Band remote sensing requirements. One of the key aspects of this antenna development is to minimize the effect of the on-orbit thermal distortion to the antenna RF performance. An analysis process which includes: 1) the on-orbit thermal analysis to obtain the temperature distribution; 2) structural deformation analysis to get the geometry of the antenna surface; and 3) the RF performance with the given deformed antenna surface has been developed to accommodate the development of this antenna technology. The detailed analysis process and some analysis results will be presented and discussed by this paper.

  20. Study of nickel hydrogen battery discharge performance after charge and stand at warm temperature

    International Nuclear Information System (INIS)

    Donley, S.W.; Verrier, D.C.

    1992-01-01

    Spacecraft batteries are normally installed in the discharged condition. It may be necessary that they be charged and trickle-charged prior to launch in an environment different from that in which they are intended to operate. The purpose of the testing described in this paper was to determine the battery capacity achieved after treatment at prelaunch conditions as a function of charge rate, charge temperature, trickle charge temperature, and time. In this testing the discharge in every case was performed under simulated space thermal conditions

  1. Simultaneous measurement of ignition energy and current signature for brush discharges

    International Nuclear Information System (INIS)

    Fast, Lars; Andersson, Birgitta; Smallwood, Jeremy; Holdstock, Paul; Paasi, Jaakko

    2011-01-01

    Accurate prediction of the probability of ignition arising from charged insulators is a crucial element of risk assessment in process industry. Incendiary brush discharges can occur when a large or grounded conductor approaches a charged insulator in the presence of a flammable atmosphere. This paper describes ignition tests based on an IEC standard method and simultaneously recorded temporal distribution of current released in the discharges, using a discharge probe integrated with the ignition probe. Ignition and non-ignition results are compared with peak discharge current and charge transferred in the discharge. No clear ignition threshold was found for either of these parameters. No major differences were found between igniting and non-igniting waveforms.

  2. Probe measurements of hydrogen fluxes during discharge cleaning in JFT-2M

    International Nuclear Information System (INIS)

    Matsuzaki, Y.

    1989-01-01

    Thermal desorption spectroscopy (TDS) has been applied during discharge cleaning in the JFT-2M tokamak to measure hydrogen fluxes. The TDS carbon sample, thickness 0.13 mm, was heated to 1000 0 C by direct current and the temperature distribution of the sample surface measured by infrared thermography. The probe was exposed to three types of plasma: Taylor-type discharge cleaning (TDC), ECR discharge cleaning (ECR-DC), and glow discharge cleaning (GDC). The TDS spectra show peak desorption at around 800 0 C. The hydrogen flux, obtained by integration of the TDS spectrum, decreases exponentially in the radial direction with decay length 7.4 cm and 5.8 cm in TDC and ECR-DC, respectively. The relation between hydrogen fluxes and water vapour production was investigated. In TDC, the amount of water vapour depends more strongly on the electron temperature of the plasma than on the hydrogen flux. In ECR-DC, the production of water vapour increases approximately linearly with the hydrogen-flux. In GDC, hydrogen fluxes were measured by TDS but no water vapour could be detected in the residual gases during the discharge. (orig.)

  3. High Power laser power conditioning system new discharge circuit research

    CERN Document Server

    Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

    2002-01-01

    The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

  4. Large thermal conductivity reduction induced by La/O vacancies in the thermoelectric LaCoO3 system.

    Science.gov (United States)

    Wang, Yang; Li, Fang; Xu, Luxiang; Sui, Yu; Wang, Xianjie; Su, Wenhui; Liu, Xiaoyang

    2011-05-16

    A series of compact La/O-vacant La(1-x)CoO(3-y) compounds were prepared by a cold high-pressure procedure, and their thermoelectric (TE) properties were investigated. Compared with the ion-substituted hole-type LaCoO(3) systems (e.g., La(1-x)Sr(x)CoO(3)), the thermal conduction of La(1-x)CoO(3-y) is noticeably reduced by the La/O vacancies, whereas the electric transport is less influenced, which results in an efficient ZT enhancement. We demonstrate that the large thermal conductivity reduction originates from the strong point-defect scattering, and La(1-x)CoO(3-y) can be rationalized as a partially filled solid solution: La(1-x)◻(x)CoO(3-y)◻(y), where ◻ denotes a vacancy. Such intrinsic thermal conductivity suppression provides an effective pathway for the design of better TE materials.

  5. A new low-cost method of reclaiming mixed foundry waste sand based on wet-thermal composite reclamation

    OpenAIRE

    Fan Zitian; Liu Fuchu; Long Wei

    2014-01-01

    A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a great realistic significance. In the study to investigate the possibility of reusing two types of waste foundry sands, resin bonded sand and clay bonded sand which came from a Chinese casting factory, a new low-cost reclamation method of the mixed foundry waste sand based on the wet-thermal composite reclamation was proposed. The wast...

  6. Thermal effects of condensing water have remained local

    International Nuclear Information System (INIS)

    Ilus, E.

    1997-01-01

    General eutrophication of the Gulf of Finland has played a major role in the biological changes that have taken place in the sea area off Loviisa nuclear power plant. The quantities of plant nutrients in the water are now 1.5 to 2 times greater than 20 years ago. Changes attributable to the thermal effects of the power plant's cooling waters have been relatively small, and they have been restricted to the immediate surroundings of the discharge area. The most distinct environmental effects have been discovered in the temperatures of sea water, in ice conditions and in water currents within the discharge area of cooling water. The most visible biological change that has a direct link to the thermal load resulting from the power plant is the more abundant aquatic flora near the discharge point of cooling water on the southwestern shores of the Haestholmsfjaerden. Similar growth of aquatic flora has also been discovered near the discharge outlet of Olkiluoto plant, although the nutrient contents of water there are only half of the values measured in the Loviisa area. Regular radiation monitoring of the areas surrounding the nuclear power plants began before the start up of the plants. The contents of radioactive substances discovered have been small and in agreement with the release data given by the power companies. (orig.)

  7. Nipple Discharge

    Science.gov (United States)

    ... any unexpected nipple discharge evaluated by a doctor. Nipple discharge in men under any circumstances could be a problem and needs further evaluation. One or both breasts may produce a nipple discharge, either spontaneously or when you squeeze your ...

  8. Thermal stability and modeling of lithium ion batteries

    Science.gov (United States)

    Botte, Gerardine Gabriela

    2000-10-01

    First-principles mathematical models were developed to examine the effect of the lithium-lithium ion interactions inside the anode particles on the performance of a lithium foil cell. Two different models were developed: the chemical potential model (CPM) that includes the lithium-lithium ion interactions inside the anode particles and the diffusion model (DIM) that does not include the interactions. Significant differences in the thermal and electrochemical performance of the cell were observed between the two approaches. The temperature of the cell predicted by the DFM is higher than the one predicted by the CPM at a given capacity. The discharge time of the cell predicted by the DFM is shorter than the one predicted by the CPM. The results indicate that the cell needs to be modeled using the CPM approach especially at high discharge rates. An evaluation of the numerical techniques, control volume formulation (CVF) and finite difference method (FDM), used for the models was performed. It is shown that the truncation error is the same for both methods when the boundary conditions are of the Dirichlet type, the system of equations are linear and represented in Cartesian coordinates. A new technique to analyze the accuracy of the methods is presented. The only disadvantage of the FDM is that it failed to conserve mass for a small number of nodes when both boundary conditions include a derivative term whereas the CVF did conserve mass for these cases. However, for a large number of nodes the FDM provides mass conservation. It is important to note that the CVF has only (DeltaX) order of accuracy for a Neumann type boundary condition whereas the FDM has (DeltaX) 2 order. The second topic of this dissertation presents a study of the thermal stability of LiPF6 EC:EMC electrolyte for lithium ion batteries. A differential scanning calorimeter (DSC) was used to perform the study of the electrolyte. For first time, the effect of different variables on its thermal stability

  9. Lung surgery - discharge

    Science.gov (United States)

    ... Lung biopsy - discharge; Thoracoscopy - discharge; Video-assisted thoracoscopic surgery - discharge; VATS - discharge ... milk) for 2 weeks after video-assisted thoracoscopic surgery and 6 to 8 weeks after open surgery. ...

  10. CFD simulation for thermal mixing of a SMART flow mixing header assembly

    International Nuclear Information System (INIS)

    Kim, Young In; Bae, Youngmin; Chung, Young Jong; Kim, Keung Koo

    2015-01-01

    Highlights: • Thermal mixing performance of a FMHA installed in SMART is investigated numerically. • Effects of operating condition and discharge hole configuration are examined. • FMHA performance satisfies the design requirements under various abnormal conditions. - Abstract: A flow mixing header assembly (FMHA) is installed in a system-integrated modular advanced reactor (SMART) to enhance the thermal mixing capability and create a uniform core flow distribution under both normal operation and accident conditions. In this study, the thermal mixing characteristics of the FMHA are investigated for various steam generator conditions using a commercial CFD code. Simulations include investigations for the effects of FMHA discharge flow rate differences, turbulence models, and steam generator conditions. The results of the analysis show that the FMHA works effectively for thermal mixing in various conditions and makes the temperature difference at the core inlet decrease noticeably. We verified that the mixing capability of the FMHA is excellent and satisfies the design requirement in all simulation cases tested here

  11. The effect of thermal conductivity of the tool electrode in spark-assisted chemical engraving gravity-feed micro-drilling

    International Nuclear Information System (INIS)

    Mousa, M; Allagui, A; Ng, H D; Wüthrich, R

    2009-01-01

    Spark-assisted chemical engraving (SACE) is a non-traditional micro-machining technology based on electrochemical discharge phenomena. In SACE gravity-feed micro-drilling, various parameters including the thermal properties of the tool electrode play a significant role in the process. Based on a series of experiments using tool electrodes with different thermal properties, the effect in SACE gravity-feed micro-drilling is discussed. It is demonstrated that machining with higher thermal conductivity tool electrodes results in faster machining during the discharge regime and slower machining during the hydrodynamic regime of SACE gravity-feed micro-drilling

  12. Resistive MHD studies of TFTR discharges

    International Nuclear Information System (INIS)

    Hughes, M.H.; Phillips, M.W.; Sabbagh, S.A.; Budny, R.V.

    1991-01-01

    MHD instabilities, thought to be resistive in character, are frequently observed in the supershot operating regime of TFTR (var-epsilon β p ≤ 0.7). These instabilities are always accompanied by substantial degradation of the confinement. Similarly of interest are recent experiments at much larger β p (var-epsilon β p ≤ 1.6), achieved through ramping the current during the beam heating phase of the discharge. In this latter regime the confinement can exceed three times the corresponding L-mode value and the β value normalized to I/aB can be as large as 4.7. Representative discharges from each of these operating regimes have been analyzed using a linear resistive MHD stability code with equilibrium pressure and q profiles obtained initially from the TRANSP analysis code. The main difference between the two types of discharge, as far as stability is concerned is shown to be the shape of the current density profile. The sensitivity to the assumed parameters is discussed. 1 ref

  13. Discharge control and evolution in TFTR

    International Nuclear Information System (INIS)

    Mueller, D.; Bell, M.; Boody, F.; Bush, C.; Cecchi, J.L.; Davis, S.; Dylla, H.F.; Efthimion, P.C.

    1985-01-01

    The Tokamak Fusion Test Reactor (TFTR) was designed to explore plasma confinement and heating at reactor-like parameters. Operation of both the toroidal field and plasma current at full design parameters has been achieved and the plasma parameters are summarized in this work. Control of the discharge evolution has played an important role in attaining these parameters. The control of impurities in a tokamak is largely a result of the choice of limiter and wall materials, conditioning techniques and gettering. The impurity control procedures adopted during the run period ending April 13, 1985 are discussed. The discussion of discharge evolution and control is broken down into discharge initiation, volt-second consumption, current and density ramp-up and ramp-down. Also discussed is control of the current ramp-up using a plasma growing technique and the control of density using gas puffing, pellet injection and neutral beam fueling, along with a discussion of the density range which is found to increase plasma current

  14. Necessary conditions for the homogeneous formation of a volume avalanche discharge with specific applications to rare gas-halide excimer laser discharges

    International Nuclear Information System (INIS)

    Levatter, J.I.

    1979-01-01

    Self-sustained/avalanche discharges are an efficient method of rare gas-halide excimer laser excitation in small systems. However, with the exceptions of the work reported here, experiments attempting to increase the laser energy output by scaling up the discharge volume and/or pulse duration have not been successful. The major problem encountered in scaling experiments has been the formation of arc channels in the discharge volume. The presence of arcing can totally disrupt proper laser operation. This problem stems from a general lack of understanding of high pressure avalanche discharge phenomena. Therefore, clarifying the basic discharge formation process and establishing a set of criteria under which a homogeneous avalanche discharge can be obtained is of central importance in defining the scaling limits of avalanche discharge lasers. The work presented here reviews the phenomena involved in high E/n (electric field to gas number density ratio) breakdown and its relationship to the formation of spatially homogeneous discharges. This relationship was first explored by A.J. Palmer in 1974. The basic requirement of his model was that the preionization density be large enough to cause an appreciable overlap of the primary electron avalanches and hence smooth out the ensuing space-charge fields to the extent that individual streamer formation would be prevented. This is the same basic model used in the more detailed discharge formation analysis developed here except that the effects of a time varying electric field caused by a finite voltage rise time and the effects due to the various electrochemical properties of the gas mixture are property taken into consideration

  15. Runaway breakdown and electrical discharges in thunderstorms

    Science.gov (United States)

    Milikh, Gennady; Roussel-Dupré, Robert

    2010-12-01

    This review considers the precise role played by runaway breakdown (RB) in the initiation and development of lightning discharges. RB remains a fundamental research topic under intense investigation. The question of how lightning is initiated and subsequently evolves in the thunderstorm environment rests in part on a fundamental understanding of RB and cosmic rays and the potential coupling to thermal runaway (as a seed to RB) and conventional breakdown (as a source of thermal runaways). In this paper, we describe the basic mechanism of RB and the conditions required to initiate an observable avalanche. Feedback processes that fundamentally enhance RB are discussed, as are both conventional breakdown and thermal runaway. Observations that provide clear evidence for the presence of energetic particles in thunderstorms/lightning include γ-ray and X-ray flux intensifications over thunderstorms, γ-ray and X-ray bursts in conjunction with stepped leaders, terrestrial γ-ray flashes, and neutron production by lightning. Intense radio impulses termed narrow bipolar pulses (or NBPs) provide indirect evidence for RB particularly when measured in association with cosmic ray showers. Our present understanding of these phenomena and their enduring enigmatic character are touched upon briefly.

  16. Wire chamber radiation detector with discharge control

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Mulera, T.A.

    1984-01-01

    A wire chamber radiation detector has spaced apart parallel electrodes and grids defining an ignition region in which charged particles or other ionizing radiations initiate brief localized avalanche discharges and defining an adjacent memory region in which sustained glow discharges are initiated by the primary discharges. Conductors of the grids at each side of the memory section extend in orthogonal directions enabling readout of the X-Y coordinates of locations at which charged particles were detected by sequentially transmitting pulses to the conductors of one grid while detecting transmissions of the pulses to the orthogonal conductors of the other grid through glow discharges. One of the grids bounding the memory region is defined by an array of conductive elements each of which is connected to the associated readout conductor through a separate resistance. The wire chamber avoids ambiguities and imprecisions in the readout of coordinates when large numbers of simultaneous or near simultaneous charged particles have been detected. Down time between detection periods and the generation of radio frequency noise are also reduced

  17. Methods and techniques for obtaining significant discharge measurements on high-voltage bushings

    Energy Technology Data Exchange (ETDEWEB)

    Jolley, H E.W.

    1965-05-01

    Forms of discharge tests are described and compared. The use of the Arman and Starr discharge bridge with cathode-ray-tube display is shown to be practicable for bushing testing up to 600 kV. Spurious discharge effects and the precautions necessary to eliminate them are discussed. Consideration is given to calibration methods and to the errors to be expected with various practical circuits. The problem of establishing safe discharge limits for bushings is considered on the basis of a large number of test results and on service experience.

  18. Non-thermal plasma at atmospheric pressure for ozone generation and volatile organic compounds decomposition

    International Nuclear Information System (INIS)

    Pekarek, S.; Khun, J.

    2006-01-01

    The non-thermal plasma technologies based on electrical discharges play an important role in ecological applications. The classical corona discharge is however relatively low power discharge. With the aim to extend its current-voltage range we studied hollow needle-to-plate DC corona discharge enhanced by the flow of a gas through the needle electrode. With this type of the discharge we performed an extensive study of ozone generation and volatile organic compounds decomposition. We found that supply of air through the needle substantially increases current-voltage range of the discharge in comparison with classical pin-to-plate corona discharge. Consequently the ozone generation as well as toluene decomposition efficiency was increased (Authors)

  19. Investigation on a hydrogel based passive thermal management system for lithium ion batteries

    International Nuclear Information System (INIS)

    Zhang, Sijie; Zhao, Rui; Liu, Jie; Gu, Junjie

    2014-01-01

    An appropriate operating temperature range is critical for the overall performance and safety of lithium-ion batteries. Considering the excellent performance of water in heat dissipation in industrial applications, in this paper, a water based PAAS (sodium polyacrylate) hydrogel thermal management system has been proposed to handle the heat surge during the operation of a Li-ion battery pack. A thermal model with constant heat generation rate is employed to simulate the high current discharge process (i.e., 10 A) on a 4S1P battery pack, which shows a good consistence with the corresponding experimental results. Further experiments on 4S1P and 5S1P battery packs validate the effectiveness of the hydrogel thermal management system in lowering the temperature increase rate of battery packs at different discharge rates and minimizing the temperature difference inside battery packs during operation, thereby enhancing the stability and safety in continuous charge and discharge process and decreasing the capacity fading rate during life cycle tests. This novel hydrogel based cooling system also possesses the characteristics of high energy efficiency, easy manufacturing process, compactness, and low cost. - Highlights: • A hydrogel thermal management system (TMS) is proposed for Li-ion battery. • It is found that the heat from internal resistance predominates at high discharge rate. • Effectiveness of hydrogel in controlling cell temperature is proved. • Battery equipped with hydrogel TMS is safer at continuous high rate cycle test. • The capacity fading rate of battery pack decreases when hydrogel TMS is implemented

  20. Growth of large aluminum nitride single crystals with thermal-gradient control

    Science.gov (United States)

    Bondokov, Robert T; Rao, Shailaja P; Gibb, Shawn Robert; Schowalter, Leo J

    2015-05-12

    In various embodiments, non-zero thermal gradients are formed within a growth chamber both substantially parallel and substantially perpendicular to the growth direction during formation of semiconductor crystals, where the ratio of the two thermal gradients (parallel to perpendicular) is less than 10, by, e.g., arrangement of thermal shields outside of the growth chamber.

  1. Performance improvement by discharge from different levels in solar storage tanks

    DEFF Research Database (Denmark)

    Furbo, Simon; Andersen, Elsa; Thür, Alexander

    2005-01-01

    The thermal advantages by utilizing discharge from different levels in solar storage tanks are investigated, both for a small SDHW system and for a solar combisystem. The investigations showed that it is possible to increase the thermal performance of both types of systems by using two draw......-off levels from the solar tanks instead of one draw-off level at a fixed position. The best position of the second draw-off level is in the middle or just above the middle of the tank. For the investigated small SDHW system with a realistic draw off hot water temperature of 40°C and 45°C and an auxiliary...... volume temperature of 50.5°C the increase of the thermal performance by the second draw-off level is about 6%. For the investigated solar combisystem the extra thermal performance by using one extra draw-off level, either for the domestic hot water heat exchanger or for the heating system, is about 3...

  2. Electrical Discharge Machining (EDM: A Review

    Directory of Open Access Journals (Sweden)

    Asfana Banu

    2016-09-01

    Full Text Available Electro discharge machining (EDM process is a non-conventional and non-contact machining operation which is used in industry for high precision products. EDM is known for machining hard and brittle conductivematerials since it can melt any electrically conductive material regardless of its hardness. The workpiece machined by EDM depends on thermal conductivity, electrical resistivity, and melting points of the materials. The tool and the workpiece are adequately both immersed in a dielectric medium, such as, kerosene, deionised water or any other suitable fluid. This paper is reviewed comprehensively on types of EDM operation. A brief discussion is also done on the machining responses and mathematical modelling.

  3. Application of large-eddy simulation to pressurized thermal shock: Assessment of the accuracy

    International Nuclear Information System (INIS)

    Loginov, M.S.; Komen, E.M.J.; Hoehne, T.

    2011-01-01

    Highlights: → We compare large-eddy simulation with experiment on the single-phase pressurized thermal shock problem. → Three test cases are considered, they cover entire range of mixing patterns. → The accuracy of the flow mixing in the reactor pressure vessel is assessed qualitatively and quantitatively. - Abstract: Pressurized Thermal Shock (PTS) is identified as one of the safety issues where Computational Fluid Dynamics (CFD) can bring real benefits. The turbulence modeling may impact overall accuracy of the calculated thermal loads on the vessel walls, therefore advanced methods for turbulent flows are required. The feasibility and mesh resolution of LES for single-phase PTS are assessed earlier in a companion paper. The current investigation deals with the accuracy of LES approach with respect to the experiment. Experimental data from the Rossendorf Coolant Mixing (ROCOM) facility is used as a basis for validation. Three test cases with different flow rates are considered. They correspond to a buoyancy-driven, a momentum-driven, and a transitional coolant mixing pattern in the downcomer. Time- and frequency-domain analysis are employed for comparison of the numerical and experimental data. The investigation shows a good qualitative prediction of the bulk flow patterns. The fluctuations are modeled correctly. A conservative estimate of the temperature drop near the wall can be obtained from the numerical results with safety factor of 1.1-1.3. In general, the current LES gives a realistic and reliable description of the considered coolant mixing experiments. The accuracy of the prediction is definitely improved with respect to earlier CFD simulations.

  4. Large eddy simulation of a T-Junction with upstream elbow: The role of Dean vortices in thermal fatigue

    International Nuclear Information System (INIS)

    Tunstall, R.; Laurence, D.; Prosser, R.; Skillen, A.

    2016-01-01

    Highlights: • A T-Junction with an upstream bend is studied using wall-resolved LES and POD. • The bend generates Dean vortices which remain prominent downstream of the junction. • Dean vortex swirl-switching results in an unsteady secondary flow about the pipe axis. • This provides a further mechanism for near-wall temperature fluctuations. • Upstream bends can have a crucial role in T-Junction thermal fatigue problems. - Abstract: Turbulent mixing of fluids in a T-Junction can generate oscillating thermal stresses in pipe walls, which may lead to high cycle thermal fatigue. This thermal stripping problem is an important safety issue in nuclear plant thermal-hydraulic systems, since it can lead to unexpected failure of the pipe material. Here, we carry out a large eddy simulation (LES) of a T-Junction with an upstream bend and use proper orthogonal decomposition (POD) to identify the dominant structures in the flow. The bend generates an unsteady secondary flow about the pipe axis, known as Dean vortex swirl-switching. This provides an additional mechanism for low-frequency near-wall temperature fluctuations downstream of the T-Junction, over those that would be produced by mixing in the same T-Junction with straight inlets. The paper highlights the important role of neighbouring pipe bends in T-Junction thermal fatigue problems and the need to include them when using CFD as a predictive tool.

  5. A quantitative analysis of the effect of ELMs on H-mode thermal energy confinement in DIII-D

    International Nuclear Information System (INIS)

    Schissel, D.P.; Osborne, T.H.; Carlstrom, T.N.; Zohm, H.

    1992-06-01

    The desire to reach ignition in future tokamaks the energy confinement time critical parameter. The most promising enhanced (over L-mode) confinement regime is the H-mode, discovered on ASDEX with neutral beam heating, and then confirmed with various auxiliary heating sources on numerous machines. The knowledge of how H-mode τ E depends on different parameters is of chemical importance to the performance predictions for next generation devices. Inter-machine H-mode total and thermal energy confinement (τ th ) scalings, which are being utilized to predict ITER thermal energy confinement, have been created for discharges where the Edge Localized Mode (ELM) instability has not been present. Confinement scaling research hm concentrated on this ELM-free H-mode phase mostly owing to the difficulty of characterizing ELM behavior. To date, long pulse H-mode operation has only been achieved by utilizing ELMs to flush out unpurities and prevent radiative collapse of the discharge. Unfortunately, accompanying the ELMS is a decrease of the plasma stored energy due to the expulsion of particles near the edge of the discharge resulting in a reduction of the steep edge electron density gradient. In order to predict ITER's H-mode τ th in the presence of ELMS, an estimated 25% confinement degradation factor has been applied to the ELM-free predictions. Our work, summarized in this paper, indicates that this 25% reduction factor is too large and instead a value of approximately 15% would be more appropriate

  6. An experimental study on the heat transfer characteristics of a heat pipe heat exchanger with latent heat storage. Part II: Simultaneous charging/discharging modes

    International Nuclear Information System (INIS)

    Liu Zhongliang; Wang Zengyi; Ma Chongfang

    2006-01-01

    In this part of the paper, the performance of the simultaneous charging/discharging operation modes of the heat pipe heat exchanger with latent heat storage is experimentally studied. The experimental results show that the device may operate under either the fluid to fluid heat transfer with charging heat to the phase change material (PCM) or the fluid to fluid heat transfer with discharging heat from the PCM modes according to the initial temperature of the PCM. The melting/solidification curves, the performances of the heat pipes and the device, the influences of the inlet temperature and the mass flow rate of the cold water on the operation performance are investigated by extensive experiments. The experimental results also disclose that under the simultaneous charging/discharging operation mode, although the heat transfer from the hot water directly to the cold water may vary, it always takes up a major part of the total heat recovered by the cold water due to the very small thermal resistance compared with the thermal resistance of the PCM side. The melting/solidification processes taking place in the simultaneous charging/discharging operation are compared with those in the charging only and discharging only processes. By applying a simplified thermal resistance analysis, a criterion for predicting the exact operation modes was derived and used to explain the observed experimental phenomena

  7. Study of a rare-gas transverse fast discharge

    Science.gov (United States)

    Chubb, D. L.; Michels, C. J.

    1979-01-01

    An experimental and analytical study of a Blumlein-type transverse fast discharge operating with He and Xe are presented. An electro-optical voltage probe was used to measure the discharge voltage, and the measured voltages were in agreement with the computed voltages. The analytical model was used to predict the dependence of the discharge efficiency for producing metastables and ions on the important plasma and external circuit parameters. In He the ion efficiency is greater than the metastable efficiency, while in Xe it is the opposite; the He ion efficiencies are much larger than in Xe, while Xe metastable efficiencies are much larger than in He. These differences between Xe and He are accounted by the large dissociative recombination rate of Xe compared with He.

  8. Homogeneous dielectric barrier discharges in atmospheric air and its influencing factor

    Science.gov (United States)

    Ran, Junxia; Li, Caixia; Ma, Dong; Luo, Haiyun; Li, Xiaowei

    2018-03-01

    The stable homogeneous dielectric barrier discharge (DBD) is obtained in atmospheric 2-3 mm air gap. It is generated using center frequency 1 kHz high voltage power supply between two plane parallel electrodes with specific alumina ceramic plates as the dielectric barriers. The discharge characteristics are studied by a measurement of its electrical discharge parameters and observation of its light emission phenomena. The results show that a large single current pulse of about 200 μs duration appearing in each voltage pulse, and its light emission is radially homogeneous and covers the entire surface of the two electrodes. The homogeneous discharge generated is a Townsend discharge during discharge. The influences of applied barrier, its thickness, and surface roughness on the transition of discharge modes are studied. The results show that it is difficult to produce a homogeneous discharge using smooth plates or alumina plate surface roughness Ra material, dielectric thickness, and dielectric surface roughness should be used, and proper applied voltage amplitude and frequency should also be used.

  9. Understanding the failure mechanisms of microwave bipolar transistors caused by electrostatic discharge

    Science.gov (United States)

    Jin, Liu; Yongguang, Chen; Zhiliang, Tan; Jie, Yang; Xijun, Zhang; Zhenxing, Wang

    2011-10-01

    Electrostatic discharge (ESD) phenomena involve both electrical and thermal effects, and a direct electrostatic discharge to an electronic device is one of the most severe threats to component reliability. Therefore, the electrical and thermal stability of multifinger microwave bipolar transistors (BJTs) under ESD conditions has been investigated theoretically and experimentally. 100 samples have been tested for multiple pulses until a failure occurred. Meanwhile, the distributions of electric field, current density and lattice temperature have also been analyzed by use of the two-dimensional device simulation tool Medici. There is a good agreement between the simulated results and failure analysis. In the case of a thermal couple, the avalanche current distribution in the fingers is in general spatially unstable and results in the formation of current crowding effects and crystal defects. The experimental results indicate that a collector-base junction is more sensitive to ESD than an emitter-base junction based on the special device structure. When the ESD level increased to 1.3 kV, the collector-base junction has been burnt out first. The analysis has also demonstrated that ESD failures occur generally by upsetting the breakdown voltage of the dielectric or overheating of the aluminum-silicon eutectic. In addition, fatigue phenomena are observed during ESD testing, with devices that still function after repeated low-intensity ESDs but whose performances have been severely degraded.

  10. Enhancement of heat transfer for thermal energy storage application using stearic acid nanocomposite with multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Li, TingXian; Lee, Ju-Hyuk; Wang, RuZhu; Kang, Yong Tae

    2013-01-01

    A latent heat storage nanocomposite made of stearic acid (SA) and multi-walled carbon nanotube (MWCNT) is prepared for thermal energy storage application. The thermal properties of the SA/MWCNT nanocomposite are characterized by SEM (scanning electron microscopy) and DSC (differential scanning calorimeter) analysis techniques, and the effects of different volume fractions of MWCNT on the heat transfer enhancement and thermal performance of stearic acid are investigated during the charging and discharging phases. The SEM analysis shows that the additive of MWCNT is uniformly distributed in the phase change material of stearic acid, and the DSC analysis reveals that the melting point of SA/MWCNT nanocomposite shifts to a lower temperature during the charging phase and the freezing point shifts to a higher temperature during the discharging phase when compared with the pure stearic acid. The experimental results show that the addition of MWCNT can improve the thermal conductivity of stearic acid effectively, but it also weakens the natural convection of stearic acid in liquid state. In comparison with the pure stearic acid, the charging rate can be decreased by about 50% while the discharging rate can be improved by about 91% respectively by using the SA/5.0% MWCNT nanocomposite. It appears that the MWCNT is a promising candidate for enhancing the heat transfer performance of latent heat thermal energy storage system. - Highlights: • A nanocomposite made of stearic acid and multi-walled carbon nanotube is prepared for thermal energy storage application. • Effects of multi-walled carbon nanotube on the thermal performance of the nanocomposite are investigated. • Multi-walled carbon nanotube enhances the thermal conductivity but weakens the natural convection of stearic acid. • Discharging/charging rates of stearic acid are increased/decreased by using multi-walled carbon nanotube

  11. Vessel Sewage Discharges: No-Discharge Zones (NDZs)

    Science.gov (United States)

    States may petition the EPA to establish areas, called no discharge zones (NDZs), where vessel sewage discharges are prohibited. This page describes how NDZs are designated, the types of designations, who enforces them, and how to comply.

  12. Hydrogenation of Penta-Graphene Leads to Unexpected Large Improvement in Thermal Conductivity.

    Science.gov (United States)

    Wu, Xufei; Varshney, Vikas; Lee, Jonghoon; Zhang, Teng; Wohlwend, Jennifer L; Roy, Ajit K; Luo, Tengfei

    2016-06-08

    Penta-graphene (PG) has been identified as a novel two-dimensional (2D) material with an intrinsic bandgap, which makes it especially promising for electronics applications. In this work, we use first-principles lattice dynamics and iterative solution of the phonon Boltzmann transport equation (BTE) to determine the thermal conductivity of PG and its more stable derivative, hydrogenated penta-graphene (HPG). As a comparison, we also studied the effect of hydrogenation on graphene thermal conductivity. In contrast to hydrogenation of graphene, which leads to a dramatic decrease in thermal conductivity, HPG shows a notable increase in thermal conductivity, which is much higher than that of PG. Considering the necessity of using the same thickness when comparing thermal conductivity values of different 2D materials, hydrogenation leads to a 63% reduction in thermal conductivity for graphene, while it results in a 76% increase for PG. The high thermal conductivity of HPG makes it more thermally conductive than most other semiconducting 2D materials, such as the transition metal chalcogenides. Our detailed analyses show that the primary reason for the counterintuitive hydrogenation-induced thermal conductivity enhancement is the weaker bond anharmonicity in HPG than PG. This leads to weaker phonon scattering after hydrogenation, despite the increase in the phonon scattering phase space. The high thermal conductivity of HPG may inspire intensive research around HPG and other derivatives of PG as potential materials for future nanoelectronic devices. The fundamental physics understood from this study may open up a new strategy to engineer thermal transport properties of other 2D materials by controlling bond anharmonicity via functionalization.

  13. Non-steady experimental investigation on an integrated thermal management system for power battery with phase change materials

    International Nuclear Information System (INIS)

    Shi, Shang; Xie, Yongqi; Li, Ming; Yuan, Yanping; Yu, Jianzu; Wu, Hongwei; Liu, Bin; Liu, Nan

    2017-01-01

    Highlights: • An integrated thermal management system for power battery is designed. • The battery temperature rise is a non-steady process for charge and discharge. • A mathematical model can accurately represent temperature rise characteristics. • The heat generation power of the battery is calculated theoretically. • The excess temperatures and thermal resistances affect the system performance. - Abstract: A large amount of heat inside the power battery must be dissipated to maintain the temperature in a safe range for the hybrid power train during high-current charging/discharging processes. In this article, a combined experimental and theoretical study has been conducted to investigate a newly designed thermal management system integrating phase change material with air cooling. An unsteady mathematical model was developed for the battery with the integrated thermal management system. Meanwhile, the heat generation power, thermal resistance, and time constant were calculated. The effect of several control parameters, such as thermal resistance, initial temperature, melting temperature and ambient temperature, on the performance of the integrated thermal management system were analyzed. The results indicated that: (1) the calculated temperature rise of the battery was in good agreement with the experimental data. The appropriate operation temperature of the battery was attained by the action of the phase change storage energy unit which is composed of copper foam and n-Eicosane, (2) the remarkable decrease of the battery temperature can be achieved by reducing the convection thermal resistance or increasing the conductivity of the phase change storage energy unit, where the latter could be the better option due to no additional energy consumption. When convective resistance and thermal resistance between the battery surface and the phase change storage energy unit are less than 2.03 K/W and 1.85 K/W, respectively, the battery will not exceed the

  14. Thermal Interaction of Closely Spaced Persons

    DEFF Research Database (Denmark)

    Brohus, Henrik; Nielsen, Peter V.; Tøgersen, Michael

    2011-01-01

    This paper presents results from a pilot study on the thermal interaction of closely spaced persons in a large enclosure. The surface temperature at different densities of persons is evaluated using a high resolution thermo vision camera in a controlled thermal environment. The corresponding ther...... thermal sensation is evaluated using questionnaires for the various densities. The results indicate that it may be acceptable to consider persons standalone, in a thermal sense, disregarding thermal interaction at usual densities in the design of large enclosures.......This paper presents results from a pilot study on the thermal interaction of closely spaced persons in a large enclosure. The surface temperature at different densities of persons is evaluated using a high resolution thermo vision camera in a controlled thermal environment. The corresponding...

  15. Extreme-UV electrical discharge source

    Science.gov (United States)

    Fornaciari, Neal R.; Nygren, Richard E.; Ulrickson, Michael A.

    2002-01-01

    An extreme ultraviolet and soft x-ray radiation electric capillary discharge source that includes a boron nitride housing defining a capillary bore that is positioned between two electrodes one of which is connected to a source of electric potential can generate a high EUV and soft x-ray radiation flux from the capillary bore outlet with minimal debris. The electrode that is positioned adjacent the capillary bore outlet is typically grounded. Pyrolytic boron nitride, highly oriented pyrolytic boron nitride, and cubic boron nitride are particularly suited. The boron nitride capillary bore can be configured as an insert that is encased in an exterior housing that is constructed of a thermally conductive material. Positioning the ground electrode sufficiently close to the capillary bore outlet also reduces bore erosion.

  16. Electrical Characterization of an RF Glow Discharge at Room Pressure

    International Nuclear Information System (INIS)

    Perez-Martinez, J. A.; Piedad-Beneitez, A. de la; Pena-Eguiluz, R.; Mercado-Cabrera, A.; Valencia A, R.; Barocio, S. R.; Lopez-Callejas, R.; Godoy-Cabrera, O. G.; Benitez-Read, J. S.; Pacheco-Sotelo, J. O.

    2006-01-01

    A non-thermal atmospheric-like plasma source able to operate at room temperature represents, by its physical nature, a considerable potential for biological applications, given its highly accurate action and extremely controllable penetration on the surface of biological tissue. As we start up a research line into this technology, we report the electrical characterization of a room pressure plasma discharge by means of a coupling network model. The discharge is produced by a 13.56MHz commercial generator. As it is impossible to measure directly its state variables (voltage and current intensity) due to the considerable perturbation created by introducing a low impedance at the system output, then an indirect estimation of such variables is achieved from experimental diagnostics at the input, so to validate the proposed electrical model

  17. Optical and thermal performance of large-size parabolic-trough solar collectors from outdoor experiments: A test method and a case study

    International Nuclear Information System (INIS)

    Valenzuela, Loreto; López-Martín, Rafael; Zarza, Eduardo

    2014-01-01

    This article presents an outdoor test method to evaluate the optical and thermal performance of parabolic-trough collectors of large size (length ≥ 100 m), similar to those currently installed in solar thermal power plants. Optical performance in line-focus collectors is defined by three parameters, peak-optical efficiency and longitudinal and transversal incidence angle modifiers. In parabolic-troughs, the transversal incidence angle modifier is usually assumed equal to 1, and the incidence angle modifier is referred to the longitudinal incidence angle modifier, which is a factor less than or equal to 1 and must be quantified. These measurements are performed by operating the collector at low fluid temperatures for reducing heat losses. Thermal performance is measured during tests at various operating temperatures, which are defined within the working temperature range of the solar field, and for the condition of maximum optical response. Heat losses are measured from both the experiments performed to measure the overall efficiency and the experiments done by operating the collector to ensure that absorber pipes are not exposed to concentrated solar radiation. The set of parameters describing the performance of a parabolic-trough collector of large size has been measured following the test procedures proposed and explained in the article. - Highlights: • Outdoor test procedures of parabolic-trough solar collector (PTC) of large size working at high temperature are described. • Optical performance measured with cold fluid temperature and thermal performance measured in the complete temperature range. • Experimental data obtained in the testing of a PTC prototype are explained

  18. Omission of Dysphagia Therapies in Hospital Discharge Communications

    Science.gov (United States)

    Kind, Amy; Anderson, Paul; Hind, Jacqueline; Robbins, JoAnne; Smith, Maureen

    2009-01-01

    Background Despite the wide implementation of dysphagia therapies, it is unclear whether these therapies are successfully communicated beyond the inpatient setting. Objective To examine the rate of dysphagia recommendation omissions in hospital discharge summaries for high-risk sub-acute care (i.e., skilled nursing facility, rehabilitation, long-term care) populations. Design Retrospective cohort study Subjects All stroke and hip fracture patients billed for inpatient dysphagia evaluations by speech-language pathologists (SLPs) and discharged to sub-acute care in 2003-2005 from a single large academic medical center (N=187). Measurements Dysphagia recommendations from final SLP hospital notes and from hospital (physician) discharge summaries were abstracted, coded, and compared for each patient. Recommendation categories included: dietary (food and liquid), postural/compensatory techniques (e.g., chin-tuck), rehabilitation (e.g., exercise), meal pacing (e.g., small bites), medication delivery (e.g., crush pills), and provider/supervision (e.g., 1-to-1 assist). Results 45% of discharge summaries omitted all SLP dysphagia recommendations. 47%(88/186) of patients with SLP dietary recommendations, 82%(93/114) with postural, 100%(16/16) with rehabilitation, 90%(69/77) with meal pacing, 95%(21/22) with medication, and 79%(96/122) with provider/supervision recommendations had these recommendations completely omitted from their discharge summaries. Conclusions Discharge summaries omitted all categories of SLP recommendations at notably high rates. Improved post-hospital communication strategies are needed for discharges to sub-acute care. PMID:20098999

  19. Temperature Distribution and Thermal Performance of an Aquifer Thermal Energy Storage System

    Science.gov (United States)

    Ganguly, Sayantan

    2017-04-01

    Energy conservation and storage has become very crucial to make use of excess energy during times of future demand. Excess thermal energy can be captured and stored in aquifers and this technique is termed as Aquifer Thermal Energy Storage (ATES). Storing seasonal thermal energy in water by injecting it into subsurface and extracting in time of demand is the principle of an ATES system. Using ATES systems leads to energy savings, reduces the dependency on fossil fuels and thus leads to reduction in greenhouse gas emission. This study numerically models an ATES system to store seasonal thermal energy and evaluates the performance of it. A 3D thermo-hydrogeological numerical model for a confined ATES system is presented in this study. The model includes heat transport processes of advection, conduction and heat loss to confining rock media. The model also takes into account regional groundwater flow in the aquifer, geothermal gradient and anisotropy in the aquifer. Results show that thermal injection into the aquifer results in the generation of a thermal-front which grows in size with time. Premature thermal-breakthrough causes thermal interference in the system when the thermal-front reaches the production well and consequences in the fall of system performance and hence should be avoided. This study models the transient temperature distribution in the aquifer for different flow and geological conditions. This may be effectively used in designing an efficient ATES project by ensuring safety from thermal-breakthrough while catering to the energy demand. Based on the model results a safe well spacing is proposed. The thermal energy discharged by the system is determined and strategy to avoid the premature thermal-breakthrough in critical cases is discussed. The present numerical model is applied to simulate an experimental field study which is found to approximate the field results quite well.

  20. Estimating extreme river discharges in Europe through a Bayesian network

    Science.gov (United States)

    Paprotny, Dominik; Morales-Nápoles, Oswaldo

    2017-06-01

    Large-scale hydrological modelling of flood hazards requires adequate extreme discharge data. In practise, models based on physics are applied alongside those utilizing only statistical analysis. The former require enormous computational power, while the latter are mostly limited in accuracy and spatial coverage. In this paper we introduce an alternate, statistical approach based on Bayesian networks (BNs), a graphical model for dependent random variables. We use a non-parametric BN to describe the joint distribution of extreme discharges in European rivers and variables representing the geographical characteristics of their catchments. Annual maxima of daily discharges from more than 1800 river gauges (stations with catchment areas ranging from 1.4 to 807 000 km2) were collected, together with information on terrain, land use and local climate. The (conditional) correlations between the variables are modelled through copulas, with the dependency structure defined in the network. The results show that using this method, mean annual maxima and return periods of discharges could be estimated with an accuracy similar to existing studies using physical models for Europe and better than a comparable global statistical model. Performance of the model varies slightly between regions of Europe, but is consistent between different time periods, and remains the same in a split-sample validation. Though discharge prediction under climate change is not the main scope of this paper, the BN was applied to a large domain covering all sizes of rivers in the continent both for present and future climate, as an example. Results show substantial variation in the influence of climate change on river discharges. The model can be used to provide quick estimates of extreme discharges at any location for the purpose of obtaining input information for hydraulic modelling.

  1. Feasibility of gas-discharge and optical methods of creating artificial ozone layers of the earth

    International Nuclear Information System (INIS)

    Batanov, G.M.; Kossyi, I.A.; Matveev, A.A.; Silakov, V.P.

    1996-01-01

    Gas-discharge (microwave) and optical (laser) methods of generating large-scale artificial ozone layers in the stratosphere are analyzed. A kinetic model is developed to calculate the plasma-chemical consequences of discharges localized in the stratosphere. Computations and simple estimates indicate that, in order to implement gas-discharge and optical methods, the operating power of ozone-producing sources should be comparable to or even much higher than the present-day power production throughout the world. Consequently, from the engineering and economic standpoints, microwave and laser methods cannot be used to repair large-scale ozone 'holes'

  2. Method and apparatus for thermal power generation

    International Nuclear Information System (INIS)

    1981-01-01

    A thermal power plant reheat cycle system is described in which the discharge from a first expansion stage is reheated prior to expansion in a subsequent expansion stage. The primary coolant has a high sheet transfer rate and can accommodate temperature changes in the reheat vapor. (U.K.)

  3. Modeling of electromagnetic and thermal diffusion in a large pure aluminum stabilized superconductor under quench

    CERN Document Server

    Gavrilin, A V

    2001-01-01

    Low temperature composite superconductors stabilized with extra large cross-section pure aluminum are currently in use for the Large Helical Device in Japan, modern big detectors such as ATLAS at CERN, and other large magnets. In these types of magnet systems, the rated average current density is not high and the peak field in a region of interest is about 2-4 T. Aluminum stabilized superconductors result in high stability margins and relatively long quench times. Appropriate quench analyses, both for longitudinal and transverse propagation, have to take into account a rather slow diffusion of current from the superconductor into the thick aluminum stabilizer. An exact approach to modeling of the current diffusion would be based on directly solving the Maxwell's equations in parallel with thermal diffusion and conduction relations. However, from a practical point of view, such an approach should be extremely time consuming due to obvious restrictions of computation capacity. At the same time, there exist cert...

  4. Experiment and simulation of a LiFePO4 battery pack with a passive thermal management system using composite phase change material and graphite sheets

    Science.gov (United States)

    Lin, Chunjing; Xu, Sichuan; Chang, Guofeng; Liu, Jinling

    2015-02-01

    A passive thermal management system (TMS) for LiFePO4 battery modules using phase change material (PCM) as the heat dissipation source to control battery temperature rise is developed. Expanded graphite matrix and graphite sheets are applied to compensate low thermal conductivity of PCM and improve temperature uniformity of the batteries. Constant current discharge and mixed charge-discharge duties were applied on battery modules with and without PCM on a battery thermal characteristics test platform. Experimental results show that PCM cooling significantly reduces the battery temperature rise during short-time intense use. It is also found that temperature uniformity across the module deteriorates with the increasing of both discharge time and current rates. The maximum temperature differences at the end of 1C and 2C-rate discharges are both less than 5 °C, indicating a good performance in battery thermal uniformity of the passive TMS. Experiments on warm-keeping performance show that the passive TMS can effectively keep the battery within its optimum operating temperature for a long time during cold weather uses. A three dimensional numerical model of the battery pack with the passive TMS was conducted using ANSYS Fluent. Temperature profiles with respect to discharging time reveal that simulation shows good agreement with experiment at 1C-discharge rate.

  5. Generation of uniform low-temperature plasma in a pulsed non-self-sustained glow discharge with a large-area hollow cathode

    Energy Technology Data Exchange (ETDEWEB)

    Akhmadeev, Yu. H.; Denisov, V. V., E-mail: volodyadenisov@yandex.ru; Koval, N. N.; Kovalsky, S. S.; Lopatin, I. V.; Schanin, P. M.; Yakovlev, V. V. [Russian Academy of Sciences, Institute of High-Current Electronics, Siberian Branch (Russian Federation)

    2017-01-15

    Generation of plasma in a pulsed non-self-sustained glow discharge with a hollow cathode with an area of ≥2 m{sup 2} at gas pressures of 0.4–1 Pa was studied experimentally. At an auxiliary arc-discharge current of 100 A and a main discharge voltage of 240 V, a pulse-periodic glow discharge with a current amplitude of 370 A, pulse duration of 340 μs, and repetition rate of 1 kHz was obtained. The possibility of creating a uniform gas-discharge plasma with a density of up to 10{sup 12} cm{sup −3} and an electron temperature of 1 eV in a volume of >0.2 m{sup 3} was demonstrated. Such plasma can be efficiently used to treat material surfaces and generate pulsed ion beams with a current density of up to 15 mA/cm{sup 2}.

  6. Characterization of a surface dielectric barrier discharge

    NARCIS (Netherlands)

    Pemen, A.J.M.; Beckers, F.J.C.M.; Heesch, van E.J.M.

    2009-01-01

    A surface dielectric barrier discharge (SDBD) reactor provides a homogeneous plasma over a large surface area. This allows surface treatments of foils, textiles or fibers. Here we present results of a study to characterize the AC and pulsed performance of SDBD with regard to ozone production,

  7. Health risk assessment for radium discharged in produced waters

    International Nuclear Information System (INIS)

    Hamilton, L.D.; Meinhold, A.F.; Nagy, J.

    1991-01-01

    Produced water generated during the production of oil and gas can contain enhanced levels of radium. This naturally occurring radioactive material (NORM) is discharged into freshwater streams, estuarine, coastal and outer continental shelf waters. Large volumes of produced waters are discharged to coastal waters along the Gulf Coast of Louisiana. The Gulf of Mexico is an important producer of fish and shellfish, and there is concern that radium discharged to coastal Louisiana could contaminate fish and shellfish used by people for food, and present a significant increase in cancer risk. This paper describes a screening-level assessment of the potential cancer risks posed by radium discharged to coastal Louisiana in oil-field produced waters. This screening analysis was performed to determine if a more comprehensive and realistic assessment is necessary, and because of the conservative assumptions embedded in the analysis overestimates the risk associated with the discharge of radium in produced waters. Two isotopes of radium (Ra-226 and Ra-228) are the radionuclides of most concern in produced water in terms of potential human health effects

  8. Characteristics of large thermal energy storage systems in Poland

    Science.gov (United States)

    Zwierzchowski, Ryszard

    2017-11-01

    In District Heating Systems (DHS) there are significant fluctuations in demand for heat by consumers during both the heating and the summer seasons. These variations are considered primarily in the 24-hour time horizon. These problems are aggravated further if the DHS is supplied by a CHP plant, because fluctuations in heat demand adversely affect to a significant degree the stable production of electricity at high overall efficiency. Therefore, introducing Thermal Energy Storage (TES) would be highly recommended on these grounds alone. The characteristics of Large (i.e. over 10 000 m3) TES in operation in Poland are presented. Information is given regarding new projects (currently in design or construction) that apply TES technology in DHS in Poland. The paper looks at the methodology used in Poland to select the TES system for a particular DHS, i.e., procedure for calculating capacity of the TES tank and the system to prevent water stored in the tank from absorbing oxygen from atmospheric air. Implementation of TES in DHS is treated as a recommended technology in the Polish District Heating sector. This technology offers great opportunities to improve the operating conditions of DHS, cutting energy production costs and emissions of pollutants to the atmosphere.

  9. Behavior of plasma facing surface in the large helical device

    International Nuclear Information System (INIS)

    Hino, T.; Nobuta, Y.; Sagara, A.

    2002-10-01

    Material probes have been installed at the inner walls along poloidal direction in LHD from the first experimental campaign. After each the campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was considerably cleaned by helium glow discharge conditionings. For the 3rd and 4th campaigns, graphite tiles were installed at entire divertor strike region, and then the wall condition significantly changed compared to the case of stainless steel wall. The erosion of graphite took place during the main discharges and the eroded carbon deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, amount of retained discharge gas such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristics of the LHD wall is a large retention of helium gas since the wall temperature is limited below 368 K. In order to reduce the recycling of discharge gas, the wall heating before the experimental campaign and the surface heating between the main discharge shots are planned. (author)

  10. Behavior of plasma facing surface in the large helical device

    International Nuclear Information System (INIS)

    Hino, T.; Nobuta, Y.; Sagara, A.

    2002-01-01

    Material probes have been installed at the inner walls along poloidal direction in LHD from the first experimental campaign. After each campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was considerably cleaned by helium glow discharge conditionings. For the 3rd and 4th campaigns, graphite tiles were installed at entire divertor strike region, and then the wall condition significantly changed compared to the case of stainless steel wall. The erosion of graphite took place during the main discharges and the eroded carbon deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, amount of retained discharge gas such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristics of the LHD wall is a large retention of helium gas since the wall temperature is limited below 368 K. In order to reduce the recycling of discharge gas, the wall heating before the experimental campaign and the surface heating between the main discharge shots are planned. (author)

  11. Behavior of plasma facing surface in the large helical device

    Energy Technology Data Exchange (ETDEWEB)

    Hino, T.; Nobuta, Y. [Hokkaido Univ., Dept. of Nuclear Engineering, Sapporo, Hokkaido (Japan); Sagara, A. [National Inst. for Fusion Science, Toki, Gifu (Japan)] [and others

    2002-11-01

    Material probes have been installed at the inner walls along poloidal direction in LHD from the first experimental campaign. After each campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was considerably cleaned by helium glow discharge conditionings. For the 3rd and 4th campaigns, graphite tiles were installed at entire divertor strike region, and then the wall condition significantly changed compared to the case of stainless steel wall. The erosion of graphite took place during the main discharges and the eroded carbon deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, amount of retained discharge gas such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristics of the LHD wall is a large retention of helium gas since the wall temperature is limited below 368 K. In order to reduce the recycling of discharge gas, the wall heating before the experimental campaign and the surface heating between the main discharge shots are planned. (author)

  12. Electromagnetic surface waves for large-area RF plasma productions between large-area planar electrodes

    International Nuclear Information System (INIS)

    Nonaka, S.

    1992-01-01

    Recently, large-area plasma production has been tested by means of a 13.56 MHz radio-frequency (RF) discharge between a pair of large-area planar electrodes, approximately 0.5 m x 1.4 m, as one of the semiconductor technologies for fabrication of large-area amorphous silicon solar cells in the ''Sunshine Project'' of the Agency of Industrial Science and Technology in Japan. We also confirmed long plasma production between a pair of long electrodes. In this paper, normal electromagnetic (EM) waves propagating in a region between a planar waveguide with one plasma and two dielectric layers are analyzed in order to study the feasibility of large-area plasma productions by EM wave-discharges between a pair of large-area RF electrodes larger than the half-wavelength of RF wave. In conclusion, plasmas higher than an electron plasma frequency will be produced by an odd TMoo surface mode. (author) 4 refs., 3 figs

  13. Thermal insulation

    International Nuclear Information System (INIS)

    Aspden, G.J.; Howard, R.S.

    1988-01-01

    The patent concerns high temperature thermal insulation of large vessels, such as the primary vessel of a liquid metal cooled nuclear reactor. The thermal insulation consists of multilayered thermal insulation modules, and each module comprises a number of metal sheet layers sandwiched between a back and front plate. The layers are linked together by straps and clips to control the thickness of the module. (U.K.)

  14. State waste discharge permit application for cooling water and condensate discharges

    Energy Technology Data Exchange (ETDEWEB)

    Haggard, R.D.

    1996-08-12

    The following presents the Categorical State Waste Discharge Permit (SWDP) Application for the Cooling Water and Condensate Discharges on the Hanford Site. This application is intended to cover existing cooling water and condensate discharges as well as similar future discharges meeting the criteria set forth in this document.

  15. Cold cathode arc model in mercury discharges

    International Nuclear Information System (INIS)

    Li, Y.M.; Byszewski, W.W.; Budinger, A.B.

    1990-01-01

    Voltage/current characteristics measured during the starting of metal halide lamps indicate a low voltage discharge when condensates (mainly mercury) are localized on the electrodes. In this case, even with a cold cathode which does not emit electrons, the current is very high and voltage across the lamp drops to about 15 to 20 V. This type of discharge is similar to the cold cathode mercury vapor arc found in mercury pool rectifiers. The cathode sheath in the mercury vapor arc is characterized by very small cathode spot size, on the order of 10 -c cm 2 , very high current density of about 10 6 A/cm 2 and very low cathode fall of approximately 10 volts. The discharge is modified and generalized to describe the cathode phenomena in the cold cathode mercury vapor arc. The sensitivity of calculated discharge parameters with respect to such modifications were examined. Results show that the cathode fall voltage remains fairly constant (7-8 volts) with large fractional variations of metastable mercury atoms bombarding the cathode. This result compares very well with experimental waveforms when anode fall and plasma voltage approximations are incorporated

  16. A compact system for large-area thermal nanoimprint lithography using smart stamps

    International Nuclear Information System (INIS)

    Pedersen, R H; Hansen, O; Kristensen, A

    2008-01-01

    We present a simple apparatus for thermal nanoimprint lithography. In this work, the stamp is designed to significantly reduce the requirements for pressure application on the external imprint system. By MEMS-based processing, an air cavity inside the stamp is created, and the required pressure for successful imprint is reduced. Additionally, the stamp is capable of performing controlled demolding after imprint. Due to the complexity of the stamp, a compact and cost-effective imprint apparatus can be constructed. The design and fabrication of the advanced stamp as well as the simple imprint equipment is presented. Test imprints of micrometer- and nanometer-scale structures are performed and characterized with respect to uniformity across a large area (35 mm radius). State-of-the-art uniformity for µm-scale features is demonstrated

  17. Thermal properties of sodium-sulfur cells

    Energy Technology Data Exchange (ETDEWEB)

    Knoedler, R.

    1984-01-01

    The heat capacity and the rate of heat generation of Na/S cells during discharge and charge were determined. The measurements were carried out in a furnace with very low heat loss and low heat capacity (quasi-adiabatic arrangement). A linear relationship between (1/I)(dT/dt) and I, where I is the discharge or charge current and dT/dt the temperature gradient, was obtained. From these plots the heat capacity of the cell and the entropy term could be determined. It turned out that, due to a steep entropy increase beyond about 80% state of discharge, the heat generation rate increased strongly in this region. During charging, this effect causes a cooling effect at low currents. The data presented here are important for the design of the thermal management system of an electric vehicle battery. 10 references, 7 figures, 1 table.

  18. Power source for inactivation of micro-organisms with partial high voltage discharge in a continuous process

    NARCIS (Netherlands)

    Creyghton, Y.; Beurskens, R.; Fiala, A.; Haan, S.W.H. de

    2002-01-01

    An electrical discharge technology is investigated as non-thermal method for inactivation of microorganisms. Potential applications include treatment of drinking water (e.g. legionella) and liquid food pasteurization (e.g. fruit juices). A strong interest exists in mild food conservation processes

  19. The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

    International Nuclear Information System (INIS)

    Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen

    2013-01-01

    Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage

  20. The transition mechanism from a symmetric single period discharge to a period-doubling discharge in atmospheric helium dielectric-barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Dingzong; Wang, Yanhui; Wang, Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2013-06-15

    Period-doubling and chaos phenomenon have been frequently observed in atmospheric-pressure dielectric-barrier discharges. However, how a normal single period discharge bifurcates into period-doubling state is still unclear. In this paper, by changing the driving frequency, we study numerically the transition mechanisms from a normal single period discharge to a period-doubling state using a one-dimensional self-consistent fluid model. The results show that before a discharge bifurcates into a period-doubling state, it first deviates from its normal operation and transforms into an asymmetric single period discharge mode. Then the weaker discharge in this asymmetric discharge will be enhanced gradually with increasing of the frequency until it makes the subsequent discharge weaken and results in the discharge entering a period-doubling state. In the whole transition process, the spatial distribution of the charged particle density and the electric field plays a definitive role. The conclusions are further confirmed by changing the gap width and the amplitude of the applied voltage.

  1. Simulation of chlorinated water discharges from power plants on estuaries and rivers

    International Nuclear Information System (INIS)

    Eraslan, A.H.; Lietzke, M.H.; Fischer, S.K.; Kalmaz, E.V.

    1977-01-01

    The fast-transient (tidal-transient) one-dimensional discrete-element chemical transport model and its associated computer code CHMONE were applied to study the effects of chlorinated water discharges from power plants on tidal estuaries and controlled rivers. The mathematical model has the capability to predict simultaneously the hydrodynamic, thermal, and chemical composition of water as one-dimensional time-dependent distributions

  2. Electron energy distribution function in a cathode fall region of DC-glow discharge

    International Nuclear Information System (INIS)

    Elakshar, F.F.; Garamoon, A.A.; Hassouba, M.A.

    1997-01-01

    Recently a substantial effort has been devoted towards the development of a quantitative microscopic measurements in the cathode fall region of the DC-glow discharge magnetron sputtering unit. The electron energy distribution function (EEDF) has been measured using a single Langmuir probe at the edge of the cathode fall. Two groups of electrons are observed in helium and argon gas discharges. The two groups have no chance to be thermalized since they leave the cathode fall region fast. The electron temperature measurements have been compared with spectroscopic determination. Plasma density has been computed and compared with probe measurements. Sources of the two groups of electrons are also discussed. (author)

  3. Hysterectomy - vaginal - discharge

    Science.gov (United States)

    Vaginal hysterectomy - discharge; Laparoscopically assisted vaginal hysterectomy - discharge; LAVH - discharge ... you were in the hospital, you had a vaginal hysterectomy. Your surgeon made a cut in your ...

  4. Water resources research program. Volume I. Measurements of physical phenomena related to power plant waste heat discharges: Lake Michigan, 1973--1974

    International Nuclear Information System (INIS)

    Tokar, J.V.; Zivi, S.M.; Frigo, A.A.; Van Loon, L.S.; Frye, D.E.; Tome, C.

    1975-03-01

    Methodology developed for the prediction of the temporal and spatial extent of thermal plumes resulting from heated discharges as a function of environmental and power plant design and operating conditions is described. Plume temperature measurements acquired from the Point Beach and Zion Nuclear Power Plants, both located on Lake Michigan, during the past several years show the effects of two-unit operation at the plant site. The Zion plant, in contrast to the shoreline surface discharge of the Point Beach station, has offshore submerged outfalls. Measuring techniques discussed include: fluorescent dye studies of the magnitude of lateral and vertical turbulent transport in plume dispersal; simultaneous aerial infrared scanning and in situ boat measurements for thermal plume mapping; a study of the dynamic characteristics of heated discharges; and a review of data from a two-year study of nearshore ambient currents at the Point Beach plant. (U.S.)

  5. Thermal treatment effects on charge storage performance of graphene-based materials for supercapacitors.

    Science.gov (United States)

    Zhang, Hongxin; Bhat, Vinay V; Gallego, Nidia C; Contescu, Cristian I

    2012-06-27

    Graphene materials were synthesized by reduction of exfoliated graphite oxide and then thermally treated in nitrogen to improve the surface area and their electrochemical performance as electrical double-layer capacitor electrodes. The structural and surface properties of the prepared reduced graphite oxide (RGO) were investigated using atomic force microscopy, scanning electron microscopy, Raman spectra, X-ray diffraction pattern analysis, and nitrogen adsorption/desorption studies. RGO forms a continuous network of crumpled sheets, which consist of large amounts of few-layer and single-layer graphenes. Electrochemical studies were conducted by cyclic voltammetry, impedance spectroscopy, and galvanostatic charge-discharge measurements. The modified RGO materials showed enhanced electrochemical performance, with maximum specific capacitance of 96 F/g, energy density of 12.8 Wh/kg, and power density of 160 kW/kg. These results demonstrate that thermal treatment of RGO at selected conditions is a convenient and efficient method for improving its specific capacitance, energy, and power density.

  6. Theoretical study on flow-induced vibration of a cylindrical weir due to fluid discharge

    International Nuclear Information System (INIS)

    Fujita, Katsuhisa; Ito, Tomohiro; Hirota, Kazuo; Kodama, Tetsuhiko

    1994-01-01

    In a FBR, the inside of the reactor vessel is cooled by liquid sodium. Liquid sodium is supplied to the upper plenum from its bottom and discharges over the top of the cylindrical weir down to the lower plenum. The weir is so thin in order to decrease the thermal stress on it that the fluid--structure interaction becomes predominant. A fluidelastic vibration of the weir due to fluid discharge was discovered in a French FBR. In this study, a theoretical model was developed on the ''fluid--elastic mode'' instability of a cylindrical weir due to fluid discharge from the upper plenum to the lower plenum. In the analysis, the fluctuation of both the discharge flow rate over a weir due to the vibration of the cylindrical shell and the pressure in the lower plenum due to fluid discharge were formulated. Instability criteria was derived from the added damping ratio due to fluid discharge using modal analysis. The natural modes and modal mass of the weir were obtained by the analysis using the FEM code taking the fluid - structure interaction into consideration. The theoretical instability range in terms of the fall height and the flow rate is compared with the experimental results. The theoretical values showed a good agreement with the experimental ones

  7. Hip fracture - discharge

    Science.gov (United States)

    ... neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - discharge ... in the hospital for surgery to repair a hip fracture, a break in the upper part of ...

  8. Study the dispersion the possible thermal discharges to Juragua nuclear power plant. Preliminary results

    International Nuclear Information System (INIS)

    Munnoz Caravaca, A.; Artega Rodriguez, H.; Diaz Asencio, M.; Cartas Aguila, H.

    1998-01-01

    The present work has as objective to present the results the evaluation to the surface area impact to the waters cooling discharges the Juragua nuclear power plant, by means of hydrodynamic models that described the possible distribution the same ones in the boundary marine means to the location

  9. Contribution of supra-permafrost discharge to thermokarst lake water balances on the northeastern Qinghai-Tibet Plateau

    Science.gov (United States)

    Pan, Xicai; Yu, Qihao; You, Yanhui; Chun, Kwok Pan; Shi, Xiaogang; Li, Yanping

    2017-12-01

    The seasonal hydrological mechanisms of two thermokarst lakes on the northeastern Qinghai-Tibet Plateau (QTP) were characterized by three-year intensive field observations and a water balance model. In three ice-free seasons, the supra-permafrost discharge contributed a mean ratio of over 170% of the precipitation. In the ice-cover seasons, the supra-permafrost discharge contribution varied between -20% and 22% of the water storage change. Results show that a large portion of the lake water storage change is because of the supra-permafrost discharge resulting from precipitation. Furthermore, a precipitation-subsurface runoff function is preliminarily identified in which the supra-permafrost discharge nonlinearly increased with more precipitation. Our results show that the recent lake expansion is linked with increasing supra-permafrost discharge dominated by precipitation. This study also suggests that we need to pay attention to the nonlinear increase of precipitation-controlled supra-permafrost discharge on the large lake expansion at the catchment scale in the QTP region, instead of only looking at the inputs (e.g., precipitation and river discharge) as shown in the previous studies.

  10. Geographic analysis of thermal equilibria: A bioenergetic model for predicting thermal response of aquatic insect communities

    International Nuclear Information System (INIS)

    Sweeney, B.W.; Newbold, J.D.; Vannote, R.L.

    1991-12-01

    The thermal regime immediately downstream from bottom release reservoirs is often characterized by reduced diel and seasonal (winter warm/summer cool) conditions. These unusual thermal patterns have often been implicated as a primary factor underlying observed downstream changes in the species composition of aquatic macroinvertebrate communities. The potential mechanisms for selective elimination of benthic species by unusual thermal regimes has been reviewed. Although the effects of temperature on the rate and magnitude of larval growth and development has been included in the list of potential mechanisms, only recently have field studies below dams focused on this interrelationship. This study investigates the overall community structure as well as the seasonal pattern of larval growth and development for several univoltine species of insects in the Delaware River below or near the hypolimnetic discharge of the Cannonsville and Pepeacton dams. These dams, which are located on the West and East branches of the Delaware River, respectively, produce a thermal gradient extending about 70 km downstream

  11. Travelling-wave-sustained discharges

    International Nuclear Information System (INIS)

    Schlueter, Hans; Shivarova, Antonia

    2007-01-01

    This review is on discharges maintained by travelling waves: new plasma sources, discovered in 1974 and considered as a prototype of the gas discharges according to their definition as nonlinear systems which unify in a self-consistent manner plasmas and fields. In the presentation here of the fluid-plasma models of the diffusion-controlled regime of the travelling-wave-sustained discharges (TWSDs), the basic features of the discharge maintenance-the discharge self-consistency and the electron heating in the high-frequency field-are stressed. Operation of stationary and pulsed discharges, discharge maintenance without and in external magnetic fields as well as discharge production in different gases (argon, helium, helium-argon gas mixtures and hydrogen) are covered. Modulation instability of diffusion-controlled discharges and discharge filamentation at higher gas pressures are also included in the review. Experimental findings which motivate aspects of the reported modelling are pointed out

  12. Development and prototype testing of MgCl 2 /graphite foam latent heat thermal energy storage system

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dileep; Yu, Wenhua; Zhao, Weihuan; Kim, Taeil; France, David M.; Smith, Roger K.

    2018-01-01

    Composites of graphite foam infiltrated with a magnesium chloride phase-change material have been developed as high-temperature thermal energy storage media for concentrated solar power applications. This storage medium provides a high thermal energy storage density, a narrow operating temperature range, and excellent heat transfer characteristics. In this study, experimental investigations were conducted on laboratory-scale prototypes with magnesium chloride/graphite foam composite as the latent heat thermal energy storage system. Prototypes were designed and built to monitor the melt front movement during the charging/discharging tests. A test loop was built to ensure the charging/discharging of the prototypes at temperatures > 700 degrees C. Repeated thermal cycling experiments were carried out on the fabricated prototypes, and the experimental temperature profiles were compared to the predicted results from numerical simulations using COMSOL Multiphysics software. Experimental results were found to be in good agreement with the simulations to validate the thermal models.

  13. Ankle replacement - discharge

    Science.gov (United States)

    ... total - discharge; Total ankle arthroplasty - discharge; Endoprosthetic ankle replacement - discharge; Osteoarthritis - ankle ... You had an ankle replacement. Your surgeon removed and reshaped ... an artificial ankle joint. You received pain medicine and were ...

  14. Asthma - child - discharge

    Science.gov (United States)

    Pediatric asthma - discharge; Wheezing - discharge; Reactive airway disease - discharge ... Your child has asthma , which causes the airways of the lungs to swell and narrow. In the hospital, the doctors and nurses helped ...

  15. Glow discharging device

    International Nuclear Information System (INIS)

    Maeno, Katsuki; Kawasaki, Kozo; Hiratsuka, Hajime; Kawashima, Shuichi.

    1989-01-01

    In a thermonuclear device, etc. impurities adsorbed to inner walls of a vacuum vessel by glow discharge are released to clean the vacuum vessel for preventing intrusion of the impurities into plasmas. The object of the present invention is to minimize the capacity of a power source equipment for the glow discharge device to the least extent. That is, a stabilization resistance is connected in series between each of a plurality of anodes which are inserted and arranged at the inside of a vacuum vessel as a cathode and a power source respectively. The resistance value R is selected so as to satisfy the relation: R < (Vi - Vm)/Ii, in which Vi: glow discharge starting voltage, Vm: glow discharge keeping voltage, Ii: glow discharge starting current. Accordingly, if a voltage is applied from a power source to a plurality of anodes, scattering of electric discharge between the anodes can be suppressed and the effect of voltage drop during discharge by the stabilization resistance can be eliminated. As a result, it is possible to provide an economically advantageous glow discharge device with the capacity for the power source facility being to the least extent. (K.M.)

  16. Evolution of the discharge impact assessments in the French regulation framework

    International Nuclear Information System (INIS)

    Chartier, M.; Despres, A.; Guillaume, R.; Plazanic, P.; Supervil, S.; Hubert, P.

    2000-01-01

    groups, realistic dose calculations (no more >), combination of impacts of liquid and gaseous discharges and possibly of direct shine from installation, combined analysis of the effects of chemical and radioactive discharges (possibly thermal discharges), taking into account uncertainties, demonstration of optimisation. The state of the art with respect to those various improvements is discussed together with differences with the previous approach of radiological impact assessments (dose envelope assessments, liquid and gaseous impact assessed separately, deterministic calculations, no optimisation demonstrations). 3. New evolutions wished by the experts of IPSN are sketched out: systematic a posteriori assessment of the doses due to real discharges, more quantitative approach of uncertainty, more formalised and quantitative approach of optimisation. 4. Eventually, the scope of discharge authorisations is discussed in connection with the definition of the > (as opposed to incidental/accidental situation). (author)

  17. Strategies for emission reduction from thermal power plants.

    Science.gov (United States)

    Prisyazhniuk, Vitaly A

    2006-07-01

    Major polluters of man's environment are thermal power stations (TPS) and power plants, which discharge into the atmosphere the basic product of carbon fuel combustion, CO2, which results in a build-up of the greenhouse effect and global warm-up of our planet's climate. This paper is intended to show that the way to attain environmental safety of the TPS and to abide by the decisions of the Kyoto Protocol lies in raising the efficiency of the heat power stations and reducing their fuel consumption by using nonconventional thermal cycles. Certain equations have been derived to define the quantitative interrelationship between the growth of efficiency of the TPS, decrease in fuel consumption and reduction of discharge of dust, fuel combustion gases, and heat into the environment. New ideas and new technological approaches that result in raising the efficiency of the TPS are briefly covered: magneto-hydrodynamic resonance, the Kalina cycle, and utilizing the ambient heat by using, as the working medium, low-boiling substances.

  18. Feasibility Study for Electrical Discharge Machining of Large DU-Mo Castings

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Mary Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Dombrowski, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Clarke, Kester Diederik [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Forsyth, Robert Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Aikin, Robert M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Alexander, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Tegtmeier, Eric Lee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Robison, Jeffrey Curt [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Beard, Timothy Vance [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Edwards, Randall Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Mauro, Michael Ernest [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Scott, Jeffrey E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division; Strandy, Matthew Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). SIGMA Division

    2016-10-31

    U-10 wt. % Mo (U-10Mo) alloys are being developed as low enrichment monolithic fuel for the CONVERT program. Optimization of processing for the monolithic fuel is being pursued with the use of electrical discharge machining (EDM) under CONVERT HPRR WBS 1.2.4.5 Optimization of Coupon Preparation. The process is applicable to manufacturing experimental fuel plate specimens for the Mini-Plate-1 (MP-1) irradiation campaign. The benefits of EDM are reduced machining costs, ability to achieve higher tolerances, stress-free, burr-free surfaces eliminating the need for milling, and the ability to machine complex shapes. Kerf losses are much smaller with EDM (tenths of mm) compared to conventional machining (mm). Reliable repeatability is achievable with EDM due to its computer-generated machining programs.

  19. Feasibility Study for Electrical Discharge Machining of Large DU-Mo Castings

    International Nuclear Information System (INIS)

    Hill, Mary Ann; Dombrowski, David E.; Clarke, Kester Diederik; Forsyth, Robert Thomas; Aikin, Robert M.; Alexander, David John; Tegtmeier, Eric Lee; Robison, Jeffrey Curt; Beard, Timothy Vance; Edwards, Randall Lynn; Mauro, Michael Ernest; Scott, Jeffrey E.; Strandy, Matthew Thomas

    2016-01-01

    U-10 wt. % Mo (U-10Mo) alloys are being developed as low enrichment monolithic fuel for the CONVERT program. Optimization of processing for the monolithic fuel is being pursued with the use of electrical discharge machining (EDM) under CONVERT HPRR WBS 1.2.4.5 Optimization of Coupon Preparation. The process is applicable to manufacturing experimental fuel plate specimens for the Mini-Plate-1 (MP-1) irradiation campaign. The benefits of EDM are reduced machining costs, ability to achieve higher tolerances, stress-free, burr-free surfaces eliminating the need for milling, and the ability to machine complex shapes. Kerf losses are much smaller with EDM (tenths of mm) compared to conventional machining (mm). Reliable repeatability is achievable with EDM due to its computer-generated machining programs.

  20. Thermal performance analysis of reciprocating compressor with stepless capacity control system

    International Nuclear Information System (INIS)

    Bin, Tang; Yuanyang, Zhao; Liansheng, Li; Guangbin, Liu; Le, Wang; Qichao, Yang; Haiping, Xu; Feng, Zhu; Wenhui, Meng

    2013-01-01

    On the basic principle of stepless capacity control system for large reciprocating compressor, the thermal cycle was analyzed. The equations for the process of suction, reverse flow, compression, discharge and expansion of clearance gas were established. According to these equations, p–V diagrams at various situations were simulated. An experimental platform was setup and the compressor with designed stepless capacity control system run well. The experimental results show that the capacity of compressor can be regulated steplessly, and the motor power is reduced proportionally with respect to the reduction of capacity. During the suction process, both the flow resistance of valve and the pressure fluctuation in cylinder can be reduced by opening the suction valves with the actuators. The simulated and experimental results showed good coincidence. The clearance volume and valve clearance Mach number had a negative influence on the thermal performance of compressor with stepless capacity control system. -- Highlights: ► Flow resistance of valve can be reduced and pressure fluctuation can be reduced. ► Equivalent Mach number of reverse flow is much higher than that of suction process. ► Response of stepless capacity control system is important for regulation accuracy. ► Clearance and valve clearance Mach number have influence on thermal performance

  1. Experimental study and modelling of X-ray photo-triggering of a discharge for exciplex laser

    International Nuclear Information System (INIS)

    Louvet, Yolande

    1986-01-01

    As the excitation of the laser medium by using a photo-triggered discharge revealed to be more reliable that an excitation by pre-ionised discharge, this research thesis reports the use of such an excitation and the study of initiation mechanisms for discharges photo-triggered by X rays. The author first recalls the main characteristics of excimer and exciplex systems, and presents the principle of discharge photo-triggering. He presents the experimental set-up, and reports the use of an original method to characterise the X radiation. This method uses theoretical data related to Bremsstrahlung emission, and results are validated by experimental tests. Realistic data regarding X ray properties are introduced into the theoretical model which also takes X-ray-induced ionisation reactions and photo-electron energetic degradation into account. By using this model, the author determines the electron distribution function produced by the X pre-ionisation, and the resulting thermalized electron density [fr

  2. Gas-dynamic perturbations in an electric-discharge repetitively pulsed DF laser and the role of He in their suppression

    Energy Technology Data Exchange (ETDEWEB)

    Evdokimov, P A; Sokolov, D V [Russian Federal Nuclear Center ' All-Russian Research Institute of Experimental Physics' , Sarov, Nizhnii Novgorod region (Russian Federation)

    2015-11-30

    The gas-dynamic perturbations in a repetitively pulsed DF laser are studied using a Michelson interferometer. Based on the analysis of experimental data obtained in two experimental sets (working medium without buffer gas and with up to 90% of He), it is concluded that such phenomena as isentropic expansion of a thermal plug, gas heating by shock waves and resonance acoustic waves do not considerably decrease the upper limit of the pulse repetition rate below a value determined by the time of the thermal plug flush out of the discharge gap. It is suggested that this decrease for a DF laser with the SF{sub 6} – D{sub 2} working mixture is caused by the development of overheat instability due to an increased energy deposition into the near-electrode regions and to the formation of electrode shock waves. Addition of He to the active media of the DF laser changes the discharge structure and improves its homogeneity over the discharge gape cross section, thus eliminating the reason for the development of this instability. A signification dilution of the active medium of a DF laser with helium up to the atmospheric pressure allowed us to achieve the limiting discharge initiation frequencies with the active medium replacement ratio K ∼ 1. (active media)

  3. Reuse of discharged fuel in Bohunice-1,2 units

    International Nuclear Information System (INIS)

    Chrapciak, V.; Majercik, J.; Kacmar, M.

    2003-01-01

    During the reconstruction of Bohunice-1,2 units (1997 - 2001), their cycle lengths dropped to very short values. Because of 4-year limit to fuel residence time, refuelling with fresh 2.4 % enriched assemblies seemed to be a solution of the problem. The paper describes the implementation of a final decision to reuse 3.6 % enriched fuel discharged after 3-year irradiation in previous cycles. This decision led to a large-scale moving of discharged assemblies from spent fuel pools back to reactors (Authors)

  4. Thermoregulation and temperature relations of alligators and other large ectotherms inhabiting thermally stressed habitats. Annual progress report, 1 July 1976--30 September 1977

    International Nuclear Information System (INIS)

    Spotila, J.R.

    1977-06-01

    Progress is reported on studies of the biophysical and thermal relationships between large ectotherms and their aquatic environment. Data are reported from laboratory and field studies on alligators, turtles, and fish. Mathematical models of the effect of body size and physical characteristics on temperature regulation of ectotherms and of thermal stress in aquatic organisms were developed. Results are included of field studies on the physiological and behavioral adjustments of turtles in response to changes in water temperature produced by thermal effluents in PAR Pond at the Savannah River Ecology Laboratory

  5. Powerful highly efficient KrF lamps excited by surface and barrier discharges

    International Nuclear Information System (INIS)

    Borisov, V M; Vodchits, V A; El'tsov, A V; Khristoforov, O B

    1998-01-01

    An investigation was made of the characteristics of KrF lamps with different types of excitation by surface and barrier discharges in which the dielectric material was sapphire. The conditions were determined for the attainment of an extremely high yield of the KrF* fluorescence with the internal efficiency η in ∼30 % and 22% for pulsed surface and barrier discharges, respectively. A homogeneous surface discharge was maintained without gas circulation when the pulse repetition rate was 5 x 10 4 Hz. Quasicontinuous excitation of a surface discharge at near-atmospheric pressure made it possible to reach a KrF* fluorescence power density of about 80 W cm -3 , which was close to the limit set by the kinetics of the gaseous medium. Under prolonged excitation conditions the intensity of the UV output radiation was limited by the permissible heating of the gas to a temperature above which the operating life of the gaseous mixture containing fluorine fell steeply. This was the reason for the advantage of surface over barrier discharges: the former were characterised by a high thermal conductivity of a thin (∼0.2 mm) plasma layer on the surface of the cooled dielectric, which made it possible to construct powerful highly efficient KrF and ArF lamps emitting UV radiation of up to 1 W cm -2 intensity. (laser system components)

  6. Angioplasty and stent - heart - discharge

    Science.gov (United States)

    Drug-eluting stents - discharge; PCI - discharge; Percutaneous coronary intervention - discharge; Balloon angioplasty - discharge; Coronary angioplasty - discharge; Coronary artery angioplasty - discharge; Cardiac ...

  7. Behavior of plasma facing surfaces in the large helical device

    International Nuclear Information System (INIS)

    Hino, T.; Nobuta, Y.; Sagara, A.

    2003-01-01

    Material probes have been installed at the inner walls along the poloidal direction in LHD from the first experimental campaign. After each campaign, the impurity deposition and the gas retention have been examined to clarify the plasma surface interaction and the degree of wall cleaning. In the 2nd campaign, the entire wall was thoroughly cleaned by helium glow discharge conditioning. For the 3rd and 4th campaigns, graphite tiles were installed over the entire divertor strike region, and then the wall condition was significantly changed compared to the case of a stainless steel wall. Graphite erosion took place during the main discharges and the eroded carbon was deposited on the entire wall. In particular, the deposition thickness was large at the wall far from the plasma. Since the entire wall was well carbonized, the amount of retained discharge gases such as H and He became large. In particular, the helium retention was large at the position close to the anodes used for helium glow discharge cleanings. One characteristic of the LHD wall is a large retention of helium gas since the wall temperature is limited to below 368 K. In order to reduce the recycling of discharge gas, wall heating before the experimental campaign and surface heating between the main discharge shots are planned. (author)

  8. Heavy metals in sediments of a large, turbid tropical lake affected by anthropogenic discharges

    Energy Technology Data Exchange (ETDEWEB)

    Rosales-Hoz, L.; Carranza-Edwards, A.; Lopez-Hernandez, M. [Universidad Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias del Mar y Limnologia

    2000-01-01

    Bottom-water data and trace metal concentration of Cu, Cr, Ni, Pb, Co, Zn, and organic matter in surficial sediment samples from 13 sampling stations of Lake Chapala in Mexico were studied. The lake is turbid with a great amount of flocculated sediments as a result of wind mixing, sediment re-suspension, and Lerma River discharges. Al distribution pattern in sediments was used as an indicator of the Lerma River discharges into Lake Chapala. The highest values of Cu (33.27 ppm), Cr (81.94 ppm), Pb (99.8 ppm), and Zn (149.7 ppm) were detected in sediments near the lake outlet. The bioavailable metal fraction is low for all metals except Pb, which shows 65-93% of the total metal concentration in bioavailable form. The minimum energy zone in the lake was related to organic matter concentration and was located in the SE part of the lake. An analysis of the studied parameters shows two zones: eastern zone (fluvio-deltaic) and central-western zone (lacustrine). (orig.)

  9. Thermal analysis of large diameter container (LDC) with alternate loadings of KE Basin sludge

    International Nuclear Information System (INIS)

    MILDON, D.T.

    2003-01-01

    A thermal analysis was performed to determine temperature distribution and hydrogen generation for a Large Diameter Container (LDC) having a two layer load configuration made up of a lower layer, consisting of sludge from the weasel pit, and an upper layer, consisting of the KE Basin canister sludge. For each alternate loading, the response of the LDC during shipping and storage in a T Plant cell was determined. Results for various alternate loadings were compared to the base case previously reported in SNF--9955 [Crea, 2002], 4 identical batches each with 60% floor, 40% canister sludge. Results for various cases are summarized in Table 5 and transient histories for each case are contained in figures as noted in the table. The thermal response and hydrogen generation rate of the base case bounds all alternate loadings except the third alternate loading, where 0.8 m 3 of canister sludge is loaded on the top of 1.2 m 3 of weasel pit sludge. For this case, the peak sludge temperature exceeded 100 C during shipping after 6.8 days (Note: sludge boiling does not occur in any case because the LDC pressurizes during transport and interstitial water is never saturated)

  10. Numerical investigation of a non-aqueous lithium-oxygen battery based on lithium superoxide as the discharge product

    International Nuclear Information System (INIS)

    Tan, Peng; Ni, Meng; Shao, Zongping; Chen, Bin; Kong, Wei

    2017-01-01

    Highlights: •A macroscopic model for Li-O 2 batteries based on LiO 2 is developed. •The electrode and electrolyte properties on discharge behaviors are investigated. •A thin cathode with a large porosity is favorable for a high specific capacity. •A high catalytic activity can lead to a high discharge voltage. •The oxygen solubility has larger impacts on the discharge performance. -- Abstract: It is reported lithium superoxide as the discharge product can largely decrease the charge voltage and enable a high round-trip efficiency of lithium-oxygen (Li-O 2 ) batteries. Here, we conduct a numerical investigation of the discharge behaviors of such batteries with LiO 2 as the discharge product. A mathematical model considering the mass transport and electrochemical reaction processes is first developed, which gives good agreement of the simulated discharge voltage with the experimental data. Then, with this model, the effects of electrode and electrolyte properties on the discharge performance are detailedly investigated. It is found that a thin cathode with a large porosity is favorable for a high specific capacity, and a high catalytic activity can lead to a high discharge voltage. For the cathode with different geometrical properties, it is found that the oxygen solubility and diffusivity have similar impacts on discharge capacities, but the oxygen solubility has a larger impact on energy densities. Besides, the limitations and further developments of the present model are also discussed. The results obtained from this work may give useful guidance for the discharge performance improvements of non-aqueous Li-O 2 batteries, and provide implications for other energy storage systems with solid product formation such as Na-O 2 batteries and Li-S batteries.

  11. Thermal plasmas: fundamental aspects

    International Nuclear Information System (INIS)

    Fauchais, P.

    2005-01-01

    This article treats of thermal plasmas, i.e. mainly produced by electric arcs and RF discharges. Their main characteristic is that they are generated at a pressure close to the atmospheric pressure (between 10 4 and 10 6 Pa) and refer to the classical kinetics of the Boltzmann equation. Because of the pressure, the collisions between particles are numerous and ionization is mainly due to a thermal effect. They correspond to electron densities between 10 20 and 10 24 m -3 and temperatures between 6000 and 25000 K. In these plasmas, the electric fields and the average free trajectories are too weak to generate a ionization state by direct inelastic collision. Ionization is thus essentially a thermal phenomenon due to elastic collisions. This article presents: 1 - the particles present in a plasma: definition, energy states; 2 - characteristic data: collisions, average free path and collision cross-section, distribution function, ionization types, charged particles mobility inside an electric field, scattering, Debye length; 3 - plasmas at the thermodynamical equilibrium: conditions of equilibrium, calculation of composition, thermodynamic properties, transport properties, radiation; 4 - thermal plasmas away from equilibrium: conditions of non-equilibrium, calculation of plasma composition, calculation of transport properties, quenching phenomenon. (J.S.)

  12. Environmental and biotechnological applications of high-voltage pulsed discharges in water

    International Nuclear Information System (INIS)

    Sato, Masayuki

    2008-01-01

    A high-voltage pulse has wide application in fields such as chemistry, physics and biology and their combinations. The high-voltage pulse forms two kinds of physical processes in water, namely (a) a pulsed electric field (PEF) in the parallel electrode configuration and (b) plasma generation by a pulsed discharge in the water phase with a concentrated electric field. The PEF can be used for inactivation of bacteria in liquid foods as a non-thermal process, and the underwater plasma is applicable not only for the decomposition of organic materials in water but also for biological treatment of wastewater. These discharge states are controlled mainly by the applied pulse voltage and the electrode shape. Some examples of environmental and biotechnological applications of a high-voltage pulse are reviewed.

  13. Thermal Plasma Generators with Water Stabilized Arc

    Czech Academy of Sciences Publication Activity Database

    Hrabovský, Milan

    2009-01-01

    Roč. 2, č. 1 (2009), s. 99-104 ISSN 1876-5343 R&D Projects: GA ČR GA202/08/1084 Institutional research plan: CEZ:AV0Z20430508 Keywords : Thermal plasma * plasma torch * Gerdien arc Subject RIV: BL - Plasma and Gas Discharge Physics http://www.bentham.org/open/toppj/openaccess2.htm

  14. Synthesis and characterization of thermally stable large-pore mesoporous nanocrystallineanatase

    Energy Technology Data Exchange (ETDEWEB)

    Ermokhina, Natalia I.; Nevinskiy, Vitaly A.; Manorik, Piotr A.; Ilyin, Vladimir G. [L.V. Pisarzhevskiy Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kyiv 03028 (Ukraine); Novichenko, Viktor N.; Shcherbatiuk, Mykola M.; Klymchuk, Dmitro O. [M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2Tereshchenkivska St., 01601, Kyiv (Ukraine); Tsyba, Mykola M. [Institute for Sorption and Problems of Endoecology, National Academy of Sciences of Ukraine, 13 Naumov St., Kyiv 03164 (Ukraine); Puziy, Alexander M., E-mail: alexander.puziy@ispe.kiev.ua [Institute for Sorption and Problems of Endoecology, National Academy of Sciences of Ukraine, 13 Naumov St., Kyiv 03164 (Ukraine)

    2013-04-15

    Thermally stable mesoporous nanocrystalline TiO{sub 2} with a pure anatase structure was obtained by sol–gel synthesis (in combination with hydrothermal treatment) using titanium tetrabutoxide and dibenzo-18-crown-6 as a structure-directing agent in presence of surfactant and/or La{sup 3+} ions additives. Nanocrystalline TiO{sub 2} demonstrates various textures with a well-defined spherical morphology (micro- and nanospheres), a crystallite size of no greater than 10 nm (XRD), and a narrow pore size distribution. Spherical particles of micrometer scale in the presence of La{sup 3+} ions do not form. TiO{sub 2} calcined (at 500 °C) after hydrothermal treatment (at 175 °C) has a significantly more developed porous structure as compared with TiO{sub 2} which was not treated hydrothermally. For example, specific surface area amounts 137 m{sup 2} g{sup −1} and 69 m{sup 2} g{sup −1}, pore volume 0.98 cm{sup 3} g{sup −1} and 0.21 cm{sup 3} g{sup −1}, pore diameter 17.5 nm and 12.5 nm respectively for samples hydrothermally treated and not treated. - Graphical abstract: Large-pore mesoporous nanocristalline anatase. Highlights: ► Large-pore mesoporous nanocrystalline TiO{sub 2} was obtained by sol–gel synthesis. ► Crown ether was used as template in presence of surfactant and/or La{sup 3+} ions. ► Anatase (crystalline size<11 nm) is the only crystalline phase present in TiO{sub 2}. ► TiO{sub 2} shows well-defined homogeneous spherical morphology (micro- and nano-spheres)

  15. Pediatric heart surgery - discharge

    Science.gov (United States)

    ... discharge; Heart valve surgery - children - discharge; Heart surgery - pediatric - discharge; Heart transplant - pediatric - discharge ... Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics . 20th ed. Philadelphia, PA: Elsevier; 2016:chap 434. ...

  16. Non-thermal plasma ethanol reforming in bubbles immersed in liquids

    International Nuclear Information System (INIS)

    Levko, Dmitry; Sharma, Ashish; Raja, Laxminarayan L

    2017-01-01

    Ethanol reforming in non-thermal plasma generated in atmospheric-pressure argon bubbles immersed in liquid ethanol/water solution is studied using a self-consistent multi-species fluid model. The influence of the dielectric constant of the liquid on the plasma dynamics and its effect on the generation of active species is analyzed. Several modes of discharge are obtained for large liquid dielectric constant. In these modes, we obtain either an axial streamer or a combination of two simultaneous streamers propagating along the bubble axis and near the liquid wall. The influence of these modes on the production of active species is also studied. The main reactions responsible for the generation of molecular hydrogen and light hydrocarbon species are analyzed. A possible mechanism of hydrogen generation in liquid phase is discussed. (paper)

  17. Electrothermal Impedance Spectroscopy as a Cost Efficient Method for Determining Thermal Parameters of Lithium Ion Batteries

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Loan; Stanciu, Tiberiu

    Current lithium-ion battery research aims in not only increasing their energy density but also power density. Emerging applications of lithium-ion batteries (HEV, PHEV, grid support) are becoming more and more power demanding. The increasing charging and discharging power capability rates...... of lithium-ion batteries raises safety concerns and requires thermal management of the entire battery system. Moreover, lithium-ion battery’s temperature influences both battery short term (capacity, efficiency, self-discharge) and long-term (lifetime) behaviour. Thus, thermal modelling of lithium-ion...... battery cells and battery packs is gaining importance. Equivalent thermal circuits’ models have proven to be relatively accurate with low computational burden for the price of low spatial resolution; nevertheless, they usually require expensive equipment for parametrization. Recent research initiated...

  18. Electrothermal impedance spectroscopy as a cost efficient method for determining thermal parameters of lithium ion batteries

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Loan; Stanciu, Tiberiu

    2017-01-01

    Current lithium-ion battery research aims in not only increasing their energy density but also power density. Emerging applications of lithium-ion batteries (hybrid electric vehicles, plug-in hybrid electric vehicles, grid support) are becoming more and more power demanding. The increasing charging...... and discharging power capability rates of lithium-ion batteries raises safety concerns and requires thermal management of the entire battery system. Moreover, lithium-ion battery's temperature influences both battery short term (capacity, efficiency, self-discharge) and long-term (lifetime) behaviour. Thus......, thermal modelling of lithium-ion battery cells and battery packs is gaining importance. Equivalent thermal circuits' models have proven to be relatively accurate with a low computational burden for the price of low spatial resolution; nevertheless, they usually require expensive equipment...

  19. On the stability of a homogeneous barrier discharge in nitrogen relative to radial perturbations

    CERN Document Server

    Golubovskii, Y B; Behnke, J; Behnke, J F

    2003-01-01

    The influence of small radial perturbations of the cathode current on the characteristics of a homogeneous barrier discharge in nitrogen is investigated on the basis of a two-dimensional fluid model. In a Townsend discharge, radial fluctuations are substantially suppressed, which is the evidence of its stability. The oscillative mode of the Townsend discharge is also stable with regard to radial perturbations. As the discharge turns into a form controlled by spatial charge (a streamer is developed), disturbances of all radii grow in time. Such a behaviour testifies the instability of a streamer front and may cause the discharge filamentation. Since only the Townsend discharge is stable, it is possible to use a one-dimensional model to determine the domain of existence for a homogeneous discharge. The study of homogeneity domains by means of the one-dimensional model shows that at relatively large values of the voltage growth rate, discharge gap width, or capacitance of dielectric barriers the discharge tends ...

  20. Thermally coupled moving boundary model for charge-discharge of LiFePO4/C cells

    Science.gov (United States)

    Khandelwal, Ashish; Hariharan, Krishnan S.; Gambhire, Priya; Kolake, Subramanya Mayya; Yeo, Taejung; Doo, Seokgwang

    2015-04-01

    Optimal thermal management is a key requirement in commercial utilization of lithium ion battery comprising of phase change electrodes. In order to facilitate design of battery packs, thermal management systems and fast charging profiles, a thermally coupled electrochemical model that takes into account the phase change phenomenon is required. In the present work, an electrochemical thermal model is proposed which includes the biphasic nature of phase change electrodes, such as lithium iron phosphate (LFP), via a generalized moving boundary model. The contribution of phase change to the heat released during the cell operation is modeled using an equivalent enthalpy approach. The heat released due to phase transformation is analyzed in comparison with other sources of heat such as reversible, irreversible and ohmic. Detailed study of the thermal behavior of the individual cell components with changing ambient temperature, rate of operation and heat transfer coefficient is carried out. Analysis of heat generation in the various regimes is used to develop cell design and operating guidelines. Further, different charging protocols are analyzed and a model based methodology is suggested to design an efficient quick charging protocol.