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Sample records for actively cooled be-cu

  1. Pre-irradiation testing of actively cooled Be-Cu divertor modules

    Linke, J.; Duwe, R.; Kuehnlein, W. [Forschungszentrum Juelich GmbH (Germany)] [and others

    1995-09-01

    A set of neutron irradiation tests is prepared on different plasma facing materials (PFM) candidates and miniaturized components for ITER. Beside beryllium the irradiation program which will be performed in the High Flux Reactor (HFR) in Petten, includes different carbon fiber composites (CFQ) and tungsten alloys. The target values for the neutron irradiation will be 0.5 dpa at temperatures of 350{degrees}C and 700{degrees}C, resp.. The post irradiation examination (PIE) will cover a wide range of mechanical tests; in addition the degradation of thermal conductivity will be investigated. To determine the high heat flux (HHF) performance of actively cooled divertor modules, electron beam tests which simulate the expected heat loads during the operation of ITER, are scheduled in the hot cell electron beam facility JUDITH. These tests on a selection of different actively cooled beryllium-copper and CFC-copper divertor modules are performed before and after neutron irradiation; the pre-irradiation testing is an essential part of the program to quantify the zero-fluence high heat flux performance and to detect defects in the modules, in particular in the brazed joints.

  2. Long pulse operation with actively cooled limiters

    We present here the major results obtained with actively cooled plasma facing components during long pulse operation (plasma duration >3 x surface temperature time constant=steady-state). Shots up to 120 s have been achieved in Tore Supra when the plasma was leaning on the large inner toroidal actively cooled limiter with a moderate deposited power density heat flux (up to 0.3 MW/m2). For larger power density heat flux up to 4.5 MW/m2 (design value), modular limiters have been used. A prerequisite for any actively cooled limiter is the absence of any cooling defect (crack parallel to the surface in the tile or non-correct bonding). If a defect is present it leads to a super-brilliance event (with its corresponding local power heat flux increase) which propagates. This deleterious effect is unfortunately a runaway effect. (orig.)

  3. A fuselage/tank structure study for actively cooled hypersonic cruise vehicles: Active cooling system analysis

    Stone, J. E.

    1975-01-01

    The effects of fuselage cross section and structural arrangement on the performance of actively cooled hypersonic cruise vehicles are investigated. An active cooling system which maintains the aircraft's entire surface area at temperatures below 394 K at Mach 6 is developed along with a hydrogen fuel tankage thermal protection system. Thermodynamic characteristics of the actively cooled thermal protection systems established are summarized. Design heat loads and coolant flowrate requirements are defined for each major structural section and for the total system. Cooling system weights are summarized at the major component level. Conclusions and recommendations are included.

  4. IAEA high temperature gas cooled reactor activities

    IAEA activities on high temperature gas cooled reactors are conducted with the review and support of Member States, primarily through the International Working Group on Gas Cooled Reactors (IWGGCR). This paper summarises the results of the IAEA gas cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products, and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (author)

  5. An active cooling system for photovoltaic modules

    The electrical efficiency of photovoltaic (PV) cell is adversely affected by the significant increase of cell operating temperature during absorption of solar radiation. A hybrid photovoltaic/thermal (PV/T) solar system was designed, fabricated and experimentally investigated in this work. To actively cool the PV cells, a parallel array of ducts with inlet/outlet manifold designed for uniform airflow distribution was attached to the back of the PV panel. Experiments were performed with and without active cooling. A linear trend between the efficiency and temperature was found. Without active cooling, the temperature of the module was high and solar cells can only achieve an efficiency of 8–9%. However, when the module was operated under active cooling condition, the temperature dropped significantly leading to an increase in efficiency of solar cells to between 12% and 14%. A heat transfer simulation model was developed to compare to the actual temperature profile of PV module and good agreement between the simulation and experimental results is obtained.

  6. French activities on gas cooled reactors

    The gas cooled reactor programme in France originally consisted of eight Natural Uranium Graphite Gas Cooled Reactors (UNGG). These eight units, which are now permanently shutdown, represented a combined net electrical power of 2,375 MW and a total operational history of 163 years. Studies related to these reactors concern monitoring and dismantling of decommissioned facilities, including the development of methods for dismantling. France has been monitoring the development of HTRs throughout the world since 1979, when it halted its own HTR R and D programme. France actively participates in three CRPs set up by the IAEA. (author). 1 tab

  7. Active cooling of a mobile phone handset

    Power dissipation levels in mobile phones continue to increase due to gaming, higher power applications, and increased functionality associated with the internet. The current cooling methodologies of natural convection and radiation limit the power dissipation within a mobile phone to between 1-2 W depending on size. As power dissipation levels increase, products such as mobile phones will require active cooling to ensure that the devices operate within an acceptable temperature envelop from both user comfort and reliability perspectives. In this paper, we focus on the applied thermal engineering problem of an active cooling solution within a typical mobile phone architecture by implementing a custom centrifugal fan within the mobile phone. Its performance is compared in terms of flow rates and pressure drops, allowable phone heat dissipation and maximum phone surface temperature as this is the user constraint for a variety of simulated PCB architectures in the mobile phone. Perforated plates with varying porosity through different size orifices are used to simulate these architectures. The results show that the power level dissipated by a phone for a constant surface temperature may be increased by ∼50 - 75% depending on pressure drop induced by the internal phone architecture. Hence for successful implementation and efficient utilization of active cooling will require chip layout to be considered at the design stage.

  8. Differential rotation of cool active stars

    Petit, P.; Donati, J.-F.; Cameron, A. Collier

    2004-01-01

    The surface differential rotation of active solar-type stars can be investigated by means of Doppler and Zeeman-Doppler Imaging, both techniques enabling one to estimate the short-term temporal evolution of photospheric structures (cools spots or magnetic regions). After describing the main modeling tools recently developed to guarantee a precise analysis of differential rotation in this framework, we detail the main results obtained for a small number of active G and K fast rotating stars. W...

  9. PCM Passive Cooling System Containing Active Subsystems

    Blanding, David E.; Bass, David I.

    2005-01-01

    A multistage system has been proposed for cooling a circulating fluid that is subject to intermittent intense heating. The system would be both flexible and redundant in that it could operate in a basic passive mode, either sequentially or simultaneously with operation of a first, active cooling subsystem, and either sequentially or simultaneously with a second cooling subsystem that could be active, passive, or a combination of both. This flexibility and redundancy, in combination with the passive nature of at least one of the modes of operation, would make the system more reliable, relative to a conventional cooling system. The system would include a tube-in-shell heat exchanger, within which the space between the tubes would be filled with a phase-change material (PCM). The circulating hot fluid would flow along the tubes in the heat exchanger. In the basic passive mode of operation, heat would be conducted from the hot fluid into the PCM, wherein the heat would be stored temporarily by virtue of the phase change.

  10. Evaluation of Active Cooling Systems for Non-Residential Buildings

    M.A. Othuman Mydin

    2014-01-01

    Cooling systems are an essential element in many facets of modern society including cars, computers and buildings. Cooling systems are usually divided into two types: passive and active. Passive cooling transfers heat without using any additional energy while active cooling is a type of heat transfer that uses powered devices such as fans or pumps. This paper will focus on one particular type of passive cooling: air-conditioning systems. An air-conditioning system is defined as controlled air...

  11. Preliminary characterization of interlayer for Be/Cu sintered compacts

    Sakamoto, N.; Kawamura, H. [Oarai Research Establishment, Ibaraki-ken (Japan)

    1995-09-01

    At present, beryllium is under consideration as a main candidate material for plasma facing components of ITER, because of its many advantages such as low Z, high thermal conductivity, low tritium retention, low activation and so on. Among the different divertor design options, the duplex structure where the beryllium armor is bonded with heat sink structural materials (DS-copper, Cu-Cr-Zr and so on) is under consideration. And plasma facing components will be exposed to high heat load and high neutron flux generated by the plasma. Therefore, it is necessary to develop the reliable bonding technologies between beryllium and heat sink structural materials in order to fabricate plasma facing components which can resist those. Then, we started the bonding technology development of beryllium and copper alloy with FGM (functional gradient material) in order to reduce thermal stress due to the difference of thermal expansion between beryllium and copper alloy. As the interlayers for FGM, eleven kinds of sintered compacts in which the mixing ratio of beryllium powder and oxygen free copper powder is different, were fabricated by the hot press/HIP method. The dimension of each compact is 8mm in diameter, 2mm in thickness. Then, thermal diffusivity and specific heat of these compacts were measured by laser flash method, and thermal conductivity was calculated from those values. From metalographical observation, it became clear that the sintered compacts of mixture of beryllium powder and copper powder contain residual beryllium, copper and two kinds of intermetallic compounds, Be{sub 2}Cu({delta}) and BeCu({gamma}). From the results of thermal characterization, thermal diffusivity of interlayers increased with increase of copper containing ratio. And, specific heat gradually decreased with increase of copper containing ratio.

  12. Actively controlling coolant-cooled cold plate configuration

    Chainer, Timothy J.; Parida, Pritish R.

    2016-04-26

    Cooling apparatuses are provided to facilitate active control of thermal and fluid dynamic performance of a coolant-cooled cold plate. The cooling apparatus includes the cold plate and a controller. The cold plate couples to one or more electronic components to be cooled, and includes an adjustable physical configuration. The controller dynamically varies the adjustable physical configuration of the cold plate based on a monitored variable associated with the cold plate or the electronic component(s) being cooled by the cold plate. By dynamically varying the physical configuration, the thermal and fluid dynamic performance of the cold plate are adjusted to, for example, optimally cool the electronic component(s), and at the same time, reduce cooling power consumption used in cooling the electronic component(s). The physical configuration can be adjusted by providing one or more adjustable plates within the cold plate, the positioning of which may be adjusted based on the monitored variable.

  13. Experimental Investigation on Active Cooling for Ceramic Matrix Composite

    PENG Li-na; HE Guo-qiang; LIU Pei-jin

    2009-01-01

    Compared with conventional materials, the active cooling ceramic matrix composite used in ramjet or scramjet makes their structures lighter in mass and better in performance. In this paper, an active and a passive cooling refractory composite specimens are designed and tested with an experimental facility composed of multilayer smale scale cooling penel which consists of a water cooling system and a ceramic matrix composite specimen, and a gas generator used for providing lower and higher transfer rate gases to simulate the temperatures in combustion chamber of ramjst. The active cooling specimen can continuously suffer high surface temperature of 2 000K for 30s and that of 3 000 K for 9.3 s, respectively. The experiment results show that the active cooling composite structure is available for high-temperature condition in ramjet.

  14. Be-Cu gradient materials through controlled segregation. Basic investigations

    Muecklich, F.; Lorinser, M.; Hartmann, S.; Beinstingel, S. [Saarland Univ., Saarbruecken (Germany); Linke, J.; Roedig, M.

    1998-01-01

    The joining of materials has a fundamental problematic nature: Creating a sharp interface between two different materials causes a more or less extreme jump in the properties at this point. This may result in the failure of the component under mechanical or thermal loads. In some cases there are further difficulties caused by using a third component (e.g. the transformation of Ag-lead into Cd by neutron beams). The solution may be the creating of a functionally gradient material (FGM) Be-Cu. We discuss the advantage of such a FGM and the probabilities of an new procedure for manufacturing 1-dimensional FGMs. (author)

  15. Preliminary design activities for solar heating and cooling systems

    1978-01-01

    Information on the development of solar heating and cooling systems is presented. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities.

  16. Modeling active galactic nucleus feedback in cool-core clusters: The balance between heating and cooling

    We study the long-term evolution of an idealized cool-core galaxy cluster under the influence of momentum-driven active galactic nucleus (AGN) feedback using three-dimensional high-resolution (60 pc) adaptive mesh refinement simulations. The feedback is modeled with a pair of precessing jets whose power is calculated based on the accretion rate of the cold gas surrounding the supermassive black hole (SMBH). The intracluster medium first cools into clumps along the propagation direction of the jets. As the jet power increases, gas condensation occurs isotropically, forming spatially extended structures that resemble the observed Hα filaments in Perseus and many other cool-core clusters. Jet heating elevates the gas entropy, halting clump formation. The cold gas that is not accreted onto the SMBH settles into a rotating disk of ∼1011 M ☉. The hot gas cools directly onto the disk while the SMBH accretes from its innermost region, powering the AGN that maintains a thermally balanced state for a few Gyr. The mass cooling rate averaged over 7 Gyr is ∼30 M ☉ yr–1, an order of magnitude lower than the classic cooling flow value. Medium resolution simulations produce similar results, while in low resolution runs, the cluster experiences cycles of gas condensation and AGN outbursts. Owing to its self-regulating mechanism, AGN feedback can successfully balance cooling with a wide range of model parameters. Our model also produces cold structures in early stages that are in good agreement with the observations. However, the long-lived massive cold disk is unrealistic, suggesting that additional physical processes are still needed.

  17. Cooling Panel Optimization for the Active Cooling System of a Hypersonic Aircraft

    Youn, B.; Mills, A. F.

    1995-01-01

    Optimization of cooling panels for an active cooling system of a hypersonic aircraft is explored. The flow passages are of rectangular cross section with one wall heated. An analytical fin-type model for incompressible flow in smooth-wall rectangular ducts with coupled wall conduction is proposed. Based on this model, the a flow rate of coolant to each design minimum mass flow rate or coolant for a single cooling panel is obtained by satisfying hydrodynamic, thermal, and Mach number constraints. Also, the sensitivity of the optimal mass flow rate of coolant to each design variable is investigated. In addition, numerical solutions for constant property flow in rectangular ducts, with one side rib-roughened and coupled wall conduction, are obtained using a k-epsilon and wall function turbulence model, these results are compared with predictions of the analytical model.

  18. Evaluation of Active Cooling Systems for Non-Residential Buildings

    M.A. Othuman Mydin

    2014-05-01

    Full Text Available Cooling systems are an essential element in many facets of modern society including cars, computers and buildings. Cooling systems are usually divided into two types: passive and active. Passive cooling transfers heat without using any additional energy while active cooling is a type of heat transfer that uses powered devices such as fans or pumps. This paper will focus on one particular type of passive cooling: air-conditioning systems. An air-conditioning system is defined as controlled air movement, temperature, humidity and cleanliness of a building area. Air conditioning consists of cooling and heating. Therefore, the air-conditioning system should be able to add and remove heat from the area. An air-conditioning system is defined as a control or treatment of air in a confined space. The process that occurs is the air-conditioning system absorbs heat and dust while, at the same time, cleaning the air breathed into a closed space. The purpose of air-conditioning is to maintain a comfortable atmosphere for human life and to meet user requirements. In this paper, air-conditioning systems for non-residential buildings will be presented and discussed.

  19. Evaluation of cooling performance of thermally activated building system with evaporative cooling source for typical United States climates

    Feng, Jingjuan; Bauman, Fred

    2013-01-01

    Thermally activated building systems (TABS) are gaining popularity as a potentially energy efficient strategy for conditioning buildings. These systems can use large surfaces for heat exchange, and the temperature of the cooling water can be only a few degrees lower than the room air temperature. This small temperature difference allows the use of alternative cooling sources, for example, indirect/direct evaporative cooling, to possibly eliminate refrigerant cooling to reduce energy consumpti...

  20. Physiologic Responses Produced by Active and Passive Personal Cooling Vests

    Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Luna, Bernadette

    2000-01-01

    Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to document and compare the subjects' response to three cooling vests in their recommended configurations. The Life Enhancement Tech (LET) lightweight active cooling vest with cap, the MicroClimate Systems Change of Phase garment (MCS), and the Steele Vest were each used to cool the chest regions of 12 male and 8 female Healthy subjects (21 to 69 yr.) in this study. The subjects, seated in an upright position at normal room temperature (approx. 22 C), were tested for 60 min. with one of the cooling garments. The LET active garment had an initial coolant fluid inlet temperature of 60 F, and was ramped down to 50 F. Oral, right and left ear canal temperatures were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; and respiration were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. For men, all three vests had similar, significant cooling effects. Decreases in the average rectal temperature, oral temperature, and ear canal temperatures were approximately 0.2 C, 0.2 C and 0.1 C, respectively. In contrast to the men, the female subjects wearing the MCS and Steel vests had similar cooling responses in which the core temperature remained elevated and oral and ear canal temperatures did not drop. The LET active garment cooled most of the female subjects in this study; rectal, oral and ear temperature decreased about 0.2 C, 0.3 C and 0.3 C, respectively. These results show that the garment configurations tested do not elicit a similar thermal response in all subjects. A gender difference is evident. The LET active garment configuration was most effective in decreasing temperatures of the female subjects; the MCS

  1. Thermal fatigue cycling of Be/Cu joining mock-ups

    To evaluate beryllium-to-copper joining techniques for potential use by US manufacturers in making first wall components for International Thermonuclear Experimental Reactor (ITER), we tested two mock-ups with S65C beryllium (Be) tiles Hot Isostatic Pressing (HIP) bonded to CuCrZr heat sinks. Under the aegis of the US ITER Project Office, Sandia prepared the mock-ups working with industrial vendors and performed high heat flux testing at Sandia's Plasma Material Test Facility (PMTF) to ascertain the robustness of the Be/Cu joints to 1000 thermal fatigue cycles at a heat flux level of 1.5 MW/m2. Thermal stress analysis provided insight into choosing the heat flux and flow conditions required for accelerated fatigue testing at 1000 cycles and 1.5 MW/m2 that is comparable to the 12,000 cycles and 0.875 MW/m2 required for the ITER First Wall Qualification Mock-ups. Each mock-up had three Be tiles, 35.5 mm square and 10 mm thick, bonded to a CuCrZr heat sink 134.5 mm x 36 mm x 25 mm with a single bored 12.7 mm (dia.) cooling channel. The bonding techniques included various interlayer metallizations and HIPping at 100 MPa pressure and temperature of 580 or 560 deg. C for 2 h. Each tile had a thermocouple (TC) in the center 1 mm below the Be/Cu interface. The test arrangement allowed for both mock-ups to be tested at the same time with alternate heating and cooling cycles of equal duration of 30 s. A total power of 12.7 kW was absorbed by the heated area of 4000 mm2 during the on-cycle. The mock-up was cooled by water at 2.3 m/s (0.27 kg/s), 1 MPa and 20 deg. C inlet temperature. These operating conditions did not permit the mock-ups to cool down to their initial temperature state during the off-cycle. Both mock-ups survived 1000 cycles with no significant changes. The temperature of the top surface on each reached 254 deg. C; while the center TCs reached 136 and 139 deg. C, respectively. Despite localized changes observed in the surface emissivity, the corrected

  2. IAEA activities in Gas-cooled Reactor technology development

    The International Atomic Energy Agency (IAEA) has the charter to ''foster the exchange of scientific and technical information'', and ''encourage and assist research on, and development and practical application of, atomic energy for peaceful uses throughout the world''. This paper describes the Agency's activities in Gas-cooled Reactor (GCR) technology development

  3. IAEA activities in gas-cooled reactor technology development

    The International Atomic Energy Agency (IAEA) has the charter to ''foster the exchange of scientific and technical information'', and ''encourage and assist research on, and development and practical application of, atomic energy for peaceful uses throughout the world''. This paper describes the Agency's activities in Gas-cooled Reactor (GCR) technology development

  4. Balancing passive and active systems for evolutionary water cooled reactors

    Advanced concepts of the water-cooled reactors are intended to improve safety, economics and public perception of nuclear power. The potential inclusion of new passive means in addition or instead of traditional active systems is being considered by nuclear plant designers to reach these goals. With respect to plant safety, application of the passive means is mainly intended to simplify the safety systems and to improve their reliability, to mitigate the effect of human errors and equipment malfunction. However, some clear drawbacks and the limited experience and testing of passive systems may raise additional questions that have to be addressed in the design process for each advanced reactor. Therefore the plant designer should find a reasonable balance of active and passive means to effectively use their advantages and compensate their drawbacks. Some considerations that have to be taken into account when balancing active/passive means in advanced water-cooled reactors are discussed in this paper. (author)

  5. Ten years of maintenance on Tore Supra actively cooled components

    Tore Supra, the only superconducting Tokamak equipped of actively water cooled plasma facing components, has now completed 10 years of operation (1988-1998). The associated primary pressurised water cooling loop (4 MPa at 150 deg. C) is able to exhaust a 20 MW convected or radiated power during long pulses of 200 s. The first part of this paper is devoted to an inventory and analysis of the water leaks from the plasma facing and their consequences, such as the optimisation of the pressurised water loop emptying sequence. The experience gained during 10 years by maintenance operations has also led to an improvement of the water leak detection procedure, in order to identify as accurately as possible the location of the leak. The second part of the paper describes the improvements made on quality control of Plasma Facing Components during these last 10 years. Quality Control has been increased right through the technological developments and the manufacturing process of mock-up, prototypes and series production. A specific helium tightness procedure dedicated to water cooled components has been established, consists mainly of several validation tests under pressure and temperature operating conditions. Hence reliability of the components has been largely increased

  6. Management of a water leak on actively cooled fusion devices

    ITER will be the most important machine equipped with actively cooled plasma facing components (PFCs). In case of abnormal events during a discharge, the PFC will be submitted to localized transient phenomena (high power densities, run away electrons, etc.), leading, in the worst case, to the degradation of the PFC wall and possibly to a water leak. In any case, a leak will have important consequences for the PFCs and equipment located in the vacuum vessel or connected to the ports such as seals, pumping systems or diagnostics. Considerable experience of these events has been gained at Tore Supra over a period of more than 10 years [J.J. Cordier, Ten years of maintenance on Tore Supra actively cooled components, in: Proceedings of the 21th Symp. of Fusion Technology (SOFT), Madrid, Spain, September, 2000.], which will be useful for the next step machines. This paper describes for each leak size type the procedures for maintaining save conditions in the vacuum vessel. It also presents the methods used at Tore Supra to drain-off the primary loop circuits and to identify the leaky PFC

  7. Comparative analysis of thermally activated, environmentally friendly cooling systems

    This paper compares the relative performances of three different thermally activated, environmentally friendly cooling systems, e.g. a silica-gel-water adsorption system, a LiBr-H2O absorption system and a desiccant air system. The adsorption and absorption systems in the current study employ water as the refrigerant, while the desiccant system cools atmospheric air directly. Each of these systems can be utilized at relatively low heat source temperatures such as achieved by flat plate solar collectors, but it is unclear which of these systems is best suited to what range of heat source temperature. Our study explores answers to this question by generating quantitative results comparing their relative thermal performance, i.e. COP and refrigeration capacity, and a qualitative comparison based on the size, maturity of technology, safe operation etc. In order to provide a fair comparison between the fundamentally different systems, a UA (overall heat transfer coefficient multiplied by the heat transfer area) value of 1.0 kW deg. C-1 is considered for the heat exchanger that transfers heat from the supplied hot water. Furthermore, to compare systems of similar size, the mass of silica-gel in the adsorption and desiccant systems and the mass of LiBr-H2O solution in the absorption system were specified such that each system provides the same amount of refrigeration (8.0 kW) at a source temperature of 90 deg. C. It is found that the absorption and adsorption cooling systems have a higher refrigeration capacity at heat source temperatures below 90 deg. C, while the desiccant air system outperforms the others at temperatures above 90 deg. C

  8. Active solar heating and cooling information user study

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

    1981-01-01

    The results of a series of telephone interviews with groups of users of information on active solar heating and cooling (SHAC). An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from 19 SHAC groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Manufacturers (4 groups), Distributors, Installers, Architects, Builders, Planners, Engineers (2 groups), Representatives of Utilities, Educators, Cooperative Extension Service County Agents, Building Owners/Managers, and Homeowners (2 groups). The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

  9. Active cooling for downhole instrumentation: Preliminary analysis and system selection

    Bennett, G.A.

    1988-03-01

    A feasibility study and a series of preliminary designs and analyses were done to identify candidate processes or cycles for use in active cooling systems for downhole electronic instruments. A matrix of energy types and their possible combinations was developed and the energy conversion process for each pari was identified. The feasibility study revealed conventional as well as unconventional processes and possible refrigerants and identified parameters needing further clarifications. A conceptual design or series od oesigns for each system was formulated and a preliminary analysis of each design was completed. The resulting coefficient of performance for each system was compared with the Carnot COP and all systems were ranked by decreasing COP. The system showing the best combination of COP, exchangeability to other operating conditions, failure mode, and system serviceability is chosen for use as a downhole refrigerator. 85 refs., 48 figs., 33 tabs.

  10. Performance of active solar space-cooling systems: The 1980 cooling season

    Blum, D.; Frock, S.; Logee, T.; Missal, D.; Wetzel, P.

    1980-12-01

    Solar cooling by an absorption chiller is not a cost effective method to use solar heat. This statement is substantiated by careful analysis of each subsystem and equipment component. Good designs and operating procedures are identified. The problems which reduce cost effectiveness are pointed out. There are specific suggestions for improvements. Finally, there is a comparison of solar cooling by absorption chilling and using photovoltaic cells.

  11. Microbial activity in district cooling nets; Mikrobiell Aktivitet i Fjaerrkylenaet

    Nordling, Magnus [Swedish Corrosion Inst., Stockholm (Sweden)

    2004-07-01

    results point out the risk of only analysing the water instead of also neglecting to expose coupons and analysing the presence of biofilms on the coupons. Also made clear when using exposure containers is the advantage of having the possibility of withdrawal of coupons at different occasions, thereby being able to investigate the increase with time in concentration of micro-organisms in the biofilm. The Swedish Corrosion Institute has developed such an exposure container, and used it during phase two. It has proved to be both easy to handle and in good working order, at service for supervision of microbial activity in district cooling nets in general. Finally, recommendations for reducing the risk for biofilm formation and microbial corrosion can be stated as follows: Only water of DH quality should be used, both as basic water and feed water; Avoid additives, especially if organic; Only connect district cooling tubes which are clean on the inside; Watch over the system regarding micro-organism related problems, preferably by using exposure containers.

  12. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  13. Cooling Active Region Loops Observed With SXT and TRACE

    Winebarger, A R; Winebarger, Amy R.; Warren, Harry P.

    2005-01-01

    An Impulsive Heating Multiple Strand (IHMS) Model is able to reproduce the observational characteristics of EUV (~ 1 MK) active region loops. This model implies that some of the loops must reach temperatures where X-ray filters are sensitive (> 2.5 MK) before they cool to EUV temperatures. Hence, some bright EUV loops must be preceded by bright X-ray loops. Previous analysis of X-ray and EUV active region observations, however, have concluded that EUV loops are not preceded by X-ray loops. In this paper, we examine two active regions observed in both X-ray and EUV filters and analyze the evolution of five loops over several hours. These loops first appear bright in the X-ray images and later appear bright in the EUV images. The delay between the appearance of the loops in the X-ray and EUV filters is as little as 1 hour and as much as 3 hours. All five loops appear as single ``monolithic'' structures in the X-ray images, but are resolved into many smaller structures in the (higher resolution) EUV images. The ...

  14. High heat flux tests of small-scale Be/Cu mock-ups for ITER

    Several kinds of Be/Cu joints have been made by hot isostatic press (HIP) in China in order to develop the ITER-FW blanket fabrication technology. At the first stage, high temperature HIP technology was investigated, and both Ti film and PVD (physical vapor deposition)-coating were adopted as intermediate layers between high purity beryllium made by HIP and CuCrZr alloy. The average bonding strength of Be/CuCrZr joints is larger than 60 Mpa and a good metallurgical bonding was formed. The Be/CuCrZr joints at optimized technology can sustain 1000 cycles under an absorbed power density of about 2.5 MW·m-2, which shows relatively good thermal fatigue properties. Temperature and stress distributions were also calculated by 2D ANSYS, showing a good accord with experimental results. Low temperature HIP joining is being developed and the heat load evaluation is also under way. (author)

  15. Actively cooled plasma facing components qualification, commissioning and health monitoring

    In modern steady state magnetic fusion devices, actively cooled plasma facing components (PFC) have to handle heat fluxes in the range of 10-20 MW/m2. This generates a number of engineering constraints: the armour materials must be refractory and compatible with plasma wall interaction requirements (low sputtering and/or low atomic number); the heat sink must offer high thermal conductivity, high mechanical resistance and sufficient ductility; the component cooling system -which is generally based on the circulation of pressurized water in the PFC's heat sink - must offer high thermal heat transfer efficiency. Furthermore, the assembling of the refractory armour material onto the metallic heat sink causes generic difficulties strongly depending on thermo-mechanical properties of materials and design requirements. Life time of the PFC during plasma operation are linked to their manufacturing quality, in particular they are reduced by the possible presence of flaw assembling. The fabrication of PFC in an industrial frame including their qualification and their commissioning - which consists in checking the manufacturing quality during and at the end of manufacture - is a real challenge. From experience gained at Tore Supra on carbon fibre composite flat tiles technology components, it was assessed that a set of qualifications activities must be operated during R(and)D and manufacturing phases. Dedicated Non Destructive Technique (NDT) based on advanced active infrared thermography was developed for this purpose, afterwards, correlations between NDT, high heat flux testing and thermomechanical modelling were performed to analyse damage detection and propagation, and define an acceptance criteria valuable for industrial application. Health monitoring using lock-in technique was also recently operated in-situ of the Tore Supra tokamak for detection of possible defect propagation during operations, presence of acoustic precursor for critical heat flux detection induced

  16. Temperatures achieved in human and canine neocortex during intraoperative passive or active focal cooling.

    Smyth, Matthew D; Han, Rowland H; Yarbrough, Chester K; Patterson, Edward E; Yang, Xiao-Feng; Miller, John W; Rothman, Steven M; D'Ambrosio, Raimondo

    2015-06-01

    Focal cortical cooling inhibits seizures and prevents acquired epileptogenesis in rodents. To investigate the potential clinical utility of this treatment modality, we examined the thermal characteristics of canine and human brain undergoing active and passive surface cooling in intraoperative settings. Four patients with intractable epilepsy were treated in a standard manner. Before the resection of a neocortical epileptogenic focus, multiple intraoperative studies of active (custom-made cooled irrigation-perfused grid) and passive (stainless steel probe) cooling were performed. We also actively cooled the neocortices of two dogs with perfused grids implanted for 2 hours. Focal surface cooling of the human brain causes predictable depth-dependent cooling of the underlying brain tissue. Cooling of 0.6-2°C was achieved both actively and passively to a depth of 10-15 mm from the cortical surface. The perfused grid permitted comparable and persistent cooling of canine neocortex when the craniotomy was closed. Thus, the human cortex can easily be cooled with the use of simple devices such as a cooling grid or a small passive probe. These techniques provide pilot data for the design of a permanently implantable device to control intractable epilepsy. PMID:25902001

  17. Simulation of an active cooling system for photovoltaic modules

    Abdelhakim, Lotfi

    2016-06-01

    Photovoltaic cells are devices that convert solar radiation directly into electricity. However, solar radiation increases the photovoltaic cells temperature [1] [2]. The temperature has an influence on the degradation of the cell efficiency and the lifetime of a PV cell. This work reports on a water cooling technique for photovoltaic panel, whereby the cooling system was placed at the front surface of the cells to dissipate excess heat away and to block unwanted radiation. By using water as a cooling medium for the photovoltaic solar cells, the overheating of closed panel is greatly reduced without prejudicing luminosity. The water also acts as a filter to remove a portion of solar spectrum in the infrared band but allows transmission of the visible spectrum most useful for the PV operation. To improve the cooling system efficiency and electrical efficiency, uniform flow rate among the cooling system is required to ensure uniform distribution of the operating temperature of the PV cells. The aims of this study are to develop a 3D thermal model to simulate the cooling and heat transfer in Photovoltaic panel and to recommend a cooling technique for the PV panel. The velocity, pressure and temperature distribution of the three-dimensional flow across the cooling block were determined using the commercial package, Fluent. The second objective of this work is to study the influence of the geometrical dimensions of the panel, water mass flow rate and water inlet temperature on the flow distribution and the solar panel temperature. The results obtained by the model are compared with experimental results from testing the prototype of the cooling device.

  18. Electron yield from Be-Cu induced by highly charged Xe q+ ions

    Krása, Josef; Láska, Leoš; Stöckli, M. P.; Fehrenbach, C. W.

    2002-01-01

    Roč. 196, - (2002), s. 61-67. ISSN 0168-583X R&D Projects: GA AV ČR IAA1010105; GA MŠk LN00A100 Institutional research plan: CEZ:AV0Z1010921 Keywords : highly charged ion-induced electron emission * angle impact effect * Be-Cu Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.158, year: 2002

  19. Physics and design interplay phenomena in an actively cooled tokamak: Tore Supra

    In order to achieve long pulse high performance plasma discharges, actively cooled plasma facing components (PFCs) have been installed since the beginning of Tore Supra in 1988. So far, up to 280 MJ of energy could be removed within a single discharge of 2 mn duration. Active cooling creates a specific environment, like, e.g., constant low wall temperature (<200 deg. C) or the presence of water pipes close to the plasma boundary, as compared to inertially cooled devices. Physical processes, specific of the actively cooled environment occur, which may sometimes induce irreversible damage that would not even have been observed on conventional PFCs. After a short description of the development status of the actively cooled PFCs program at Tore Supra, the paper concentrates on those aspects where physics and design aspects are mixed, which deserve thorough analysis for the conception of a next step fusion device environment

  20. Active Cooling e-Textiles for Smart Clothing

    Seung-A Lee; Jooyong Kim

    2006-01-01

    Cooling function is definitely one of the most desirable attributes of clothing. In spite of the recent progress on phase changing material (PCM) research, the final products with sufficient amount of cooling capability have not yet to be developed in market. A new concept of cooling fabrics has been proposed by applying "Peltier effect" to textile materials. It occurs whenever electrical current flows through two dissimilar conductors; depending on the direction of current flow, the junction of the two conductors will either absorb or release heat. This effect has been tested on P-type and N-type conducting polymers. A P-type conductive polypyrrole coated fabric was synthesized by insitu polymerization on plain weave PET to make conductive fabrics. And an N-type electrically conductive material was synthesized by treatment of MWNT and polyethyleneimine (PEI). A noticeable amount of temperature difference has been found in the fabric.

  1. Activities in thermal driven cooling at Fraunhofer Umsicht

    Schwerdt, Peter

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] Thermally actuated cooling processes have reached a promising maturity to offer an environmentally acceptable solution to the growing demand for air conditioning. Using solar thermal ene...

  2. Two dimensional distribution of tritium breeding ratio and induced activity in Japanese water cooled and helium cooled test blanket modules

    Solid breeder blankets are regarded as a near-at-hand blanket concept for a fusion power demonstration plant in Japan. Test blanket module (TBM) to be tested in ITER is the most important milestone to establish the fusion demonstration blanket. For the candidate TBM's, two types of TBM, water cooled solid breeder TBM, and a helium gas cooled solid breeder TBM have been proposed and designed in JAERI. For detailed performance study under operation and after shut down, detailed neutronics analysis gives the most important design conditions, such as, distribution of tritium breeding ratio, nuclear heating rate during operation, and induced activation and decay heat after termination of irradiation. In the analysis, neutron and gamma transportation was calculated by two dimensional analysis code, DOT3.5, for two TBMs. Nuclear reaction rate and induced activation rate were evaluated by APPLE-3 and ACT-4, respectively. The analysis model included configurations of thermo-mechanical test modules and surrounding common frames for both of He cooled and water cooled TBMs. By the neutronics analysis, TBR and contact dose rate by induced activation till one year after termination of the module testing have been evaluated. For the evaluation of induced activation level change and decay heat change, the transient decreases in one year after termination of the module testing have been calculated. The time duration of the module testing before termination of testing is assumed to be 133 continuous days of full power operation. The result of TBR analysis showed that TBR distribution in the toroidal direction of TBM is not significant, however, the neutron flux decreases in the region of sidewall of common frame made of SS and water. This result shows that there is relatively large neutron loss from the TBM to the common frame. Thus, it is considered that the TBR value observed in the TBM testing may be smaller than the estimation by one dimensional neutronics analysis which does

  3. Development of conductively cooled first wall armor and actively cooled divertor structure for ITER/FER

    Based on the design requirements for the plasma facing components in ITER/FER, we have performed design studies on the conductively cooled first wall armor and the divertor plate with sliding supports. The full-scale armor tiles were fabricated for heat load tests, and good thermal performances were obtained in heat load tests of 0.2-0.4 MW/m2. It is shown by the thermomechanical analysis on the divertor plate that thermal stresses and bending deformation are reduced significantly by using the sliding supports. The divertor test module with the sliding supports has been fabricated to investigate its fabricability and to verify the functions of the sliding supports during a high heat load of about 10 MW/m2. (orig.)

  4. Active noise canceling system for mechanically cooled germanium radiation detectors

    Nelson, Karl Einar; Burks, Morgan T

    2014-04-22

    A microphonics noise cancellation system and method for improving the energy resolution for mechanically cooled high-purity Germanium (HPGe) detector systems. A classical adaptive noise canceling digital processing system using an adaptive predictor is used in an MCA to attenuate the microphonics noise source making the system more deployable.

  5. Topology Optimization of an Actively Cooled Electronics Section for Downhole Tools

    Soprani, Stefano; Klaas Haertel, Jan Hendrik; Lazarov, Boyan Stefanov;

    2015-01-01

    downhole electronics unit proved to be challenging, because of the space constraints and the proximity of the cooling zone (electronics) to the heat sink (well fluid). The topology optimization approach was therefore chosen to optimize the thermal design of the actively cooled electronics section and the...

  6. Metallographic anlaysis and strength investigation of different Be-Cu joints in the temperature range RT-3500C

    Gervash, A.A.; Giniatouline, R.N.; Mazul, I.V. [Efremov Research Institute, St. Petersburg (Russian Federation)] [and others

    1995-09-01

    The goal of this work is to estimate the strength and structure of different Be-Cu joining techniques. Brazing, diffusion bonding and joint rolling methods were chosen as ITER Be-Cu joint method candidates. Selected for ITER application Be-Cu joints were produced as technological plates (30-50 mm x 50-100 mm x thickness). AR samples for farther investigations were cutted out from initial technological plates. To compare mechanical strength of selected Be-Cu joints tensile and shearing tests of chosen candidates were carried out in the temperature range RT - 350{degrees}C. The metallographic analysis of Be-Cu crosssection was also done. Preliminary results of these tests as well as metallographic analysis data are presented. The industrial possibilities of producing required for ITER full scale Be-Cu joints are discussed.

  7. A practical cooling strategy for reducing the physiological strain associated with firefighting activity in the heat.

    Barr, D; Gregson, W; Sutton, L; Reilly, T

    2009-04-01

    The aim of this study was to establish whether a practical cooling strategy reduces the physiological strain during simulated firefighting activity in the heat. On two separate occasions under high ambient temperatures (49.6 +/- 1.8 degrees C, relative humidity (RH) 13 +/- 2%), nine male firefighters wearing protective clothing completed two 20-min bouts of treadmill walking (5 km/h, 7.5% gradient) separated by a 15-min recovery period, during which firefighters were either cooled (cool) via application of an ice vest and hand and forearm water immersion ( approximately 19 degrees C) or remained seated without cooling (control). There was no significant difference between trials in any of the dependent variables during the first bout of exercise. Core body temperature (37.72 +/- 0.34 vs. 38.21 +/- 0.17 degrees C), heart rate (HR) (81 +/- 9 vs. 96 +/- 17 beats/min) and mean skin temperature (31.22 +/- 1.04 degrees C vs. 33.31 +/- 1 degrees C) were significantly lower following the recovery period in cool compared with control (p second bout of activity in cool compared to control. Mean skin temperature, HR and thermal sensation were significantly lower during bout 2 in cool compared with control (p < 0.05). It is concluded that this practical cooling strategy is effective at reducing the physiological strain associated with demanding firefighting activity under high ambient temperatures. PMID:19401892

  8. Recent Long-Pulse Test Results of KSTAR ICRF Antenna with Active Cooling

    KSTAR ICRF (Ion Cyclotron Range of Frequency) system is being developed for the high-power and longpulse operation. For a 300 s operation at a high power of 6 MW, the antenna has many cooling channels inside the current strap, Faraday shield, cavity wall, and vacuum transmission line (VTL) to remove the dissipated RF loss power and incoming plasma heat loads. In the previous test campaign, the standoff capability was increased to 31.2 kVp, 300 s from 24.3 kVp, 300 s by applying water cooling on the ICRF antenna, but it was limited by an overheating of the vacuum feedthrough (VF) and the transmission line of the unmatched section which did not have cooling channels. During the recent RF test campaign (campaign-8), the cooling system for the VF and the transmission line of the unmatched section was developed to enhance the cooling capability. The cooling channels for inner conductors of VF and the transmission line were carefully designed and installed inside their inner conductors, which were connected in series. Outer conductors near the current maximum were also watercooled by using Al cooling blocks which have a cooling channel inside them. The high power and long pulse capabilities of the antenna were experimentally estimated with active cooling on both of the antenna and the unmatched transmission line

  9. Recent Long-Pulse Test Results of KSTAR ICRF Antenna with Active Cooling

    Bae, Y. D.; Kwak, J. G.; Yoon, J. S.; Wang, S. J. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    KSTAR ICRF (Ion Cyclotron Range of Frequency) system is being developed for the high-power and longpulse operation. For a 300 s operation at a high power of 6 MW, the antenna has many cooling channels inside the current strap, Faraday shield, cavity wall, and vacuum transmission line (VTL) to remove the dissipated RF loss power and incoming plasma heat loads. In the previous test campaign, the standoff capability was increased to 31.2 kVp, 300 s from 24.3 kVp, 300 s by applying water cooling on the ICRF antenna, but it was limited by an overheating of the vacuum feedthrough (VF) and the transmission line of the unmatched section which did not have cooling channels. During the recent RF test campaign (campaign-8), the cooling system for the VF and the transmission line of the unmatched section was developed to enhance the cooling capability. The cooling channels for inner conductors of VF and the transmission line were carefully designed and installed inside their inner conductors, which were connected in series. Outer conductors near the current maximum were also watercooled by using Al cooling blocks which have a cooling channel inside them. The high power and long pulse capabilities of the antenna were experimentally estimated with active cooling on both of the antenna and the unmatched transmission line.

  10. Actively Cooled Silicon Lightweight Mirrors for Far Infrared and Submillimeter Optical Systems Project

    National Aeronautics and Space Administration — Schafer proposes to demonstrate 2 different methods for actively cooling our 5-7.5 kg/m2 areal density Silicon Lightweight Mirrors (SLMS?) technology for future...

  11. Development and testing of heat transport fluids for use in active solar heating and cooling systems

    Parker, J. C.

    1981-01-01

    Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed.

  12. Innovative two-pipe active chilled beam system for simultaneous heating and cooling of office buildings

    Maccarini, Alessandro; Afshari, Alireza; Bergsøe, Niels Christian;

    2014-01-01

    The aim of this paper was to investigate the energy savings potential of an innovative two-pipe system in an active chilled beam application for heating and cooling of office buildings. The characteristic of the system is its ability to provide simultaneous heating and cooling by transferring...... heating, cooling and ventilation loads were calculated by the program and an annual energy consumption evaluation of the system was made. Simulation results showed that the innovative two-pipe active chilled beam system used approximately 5% less energy than a conventional four-pipe system....

  13. Analytic estimation and numerical modeling of actively cooled thermal protection systems with nickel alloys

    Wang Xinzhi; He Yurong; Zheng Yan; Ma Junjun; H. Inaki Schlaberg

    2014-01-01

    Actively cooled thermal protection system has great influence on the engine of a hypersonic vehicle, and it is significant to obtain the thermal and stress distribution in the system. So an analytic estimation and numerical modeling are performed in this paper to investigate the behavior of an actively cooled thermal protection system. The analytic estimation is based on the electric analogy method and finite element analysis (FEA) is applied to the numerical simulation. Temperature and stres...

  14. Thermo Active Building Systems – Using Building Mass To Heat and Cool

    Olesen, Bjarne W.

    2014-01-01

    Using the thermal storage capacity of the concrete slabs between each floor in multistory buildings to heat or cool is a trend that began in the early 1990s in Switzerland.1,2 Pipes carrying water for heating and cooling are embedded in the center of the concrete slab. In central Europe (Germany...... multistory buildings. By activating the building mass, there is a direct heating-cooling effect. Also, because of the thermal mass, the peak load will be reduced and some of the cooling load will be transferred beyond the time of occupancy. Because these systems for cooling operate at water temperatures...... close to room temperature, they increase the efficiency of heat pumps, ground heat exchangers and other systems using renewable energy sources....

  15. HITCAN for actively cooled hot-composite thermostructural analysis

    Chamis, C. C.; Murthy, P. L. N.; Singhal, S. N.; Lackney, J. J.

    1992-01-01

    A computer code, high temperature composite analyzer (HITCAN), was developed to analyze/design hot metal matrix composite structures. HITCAN is a general purpose code for predicting the global structural and local stress-strain response of multilayered (arbitrarily oriented) metal matrix structures both at the constituent (fiber, matrix, and interphase) and the structural level, including the fabrication process effects. The thermomechanical properties of the constituents are considered to be nonlinearly dependent on several parameters, including temperature, stress, and stress rate. The computational procedure employs an incremental iterative nonlinear approach utilizing a multifactor-interaction material behavior model, i.e., the material properties are expressed in terms of a product of several factors that affect the properties. HITCAN structural analysis capabilities (static, load stepping - a multistep static analysis with material properties updated at each step, modal, and buckling) for cooled hot structures are demonstrated through a specific example problem.

  16. Measurements in large pool fires with an actively cooled calorimeter

    The pool fire thermal test described in Safety Series 6 published by the International Atomic Energy Agency (IAEA) or Title 10, Code of Federal Regulations, Part 71 (10CFR71) in the United States is one of the most difficult tests that a container for larger ''Type B'' quantities of nuclear materials must pass. If retests of a container are required, costly redesign and project delays can result. Accurate measurements and modeling of the pool fire environment will ultimately lower container costs by assuring that containers past the pool fire test on the first attempt. Experiments indicate that the object size or surface temperature of the container can play a role in determining local heat fluxes that are beyond the effects predicted from the simple radiative heat transfer laws. An analytical model described by Nicolette and Larson 1990 can be used to understand many of these effects. In this model a gray gas represents soot particles present in the flame structure. Close to the container surface, these soot particles are convectively and radiatively cooled and interact with incident energy from the surrounding fire. This cooler soot cloud effectively prevents some thermal radiation from reaching the container surface, reducing the surface heat flux below the value predicted by a transparent medium model. With some empirical constants, the model suggested by Nicolette and Larson can be used to more accurately simulate the pool fire environment. Properly formulated, the gray gas approaches also fast enough to be used with standard commercial computer codes to analyze shipping containers. To calibrate this type of model, accurate experimental measurements of radiative absorption coefficients, flame temperatures, and other parameters are necessary. A goal of the calorimeter measurements described here is to obtain such parameters so that a fast, useful design tool for large pool fires can be constructed

  17. Measurements in large pool fires with an actively cooled calorimeter

    Koski, J.A. [Sandia National Labs., Albuquerque, NM (United States); Wix, S.D. [GRAM, Inc., Albuquerque, NM (United States)

    1995-12-31

    The pool fire thermal test described in Safety Series 6 published by the International Atomic Energy Agency (IAEA) or Title 10, Code of Federal Regulations, Part 71 (10CFR71) in the United States is one of the most difficult tests that a container for larger ``Type B`` quantities of nuclear materials must pass. If retests of a container are required, costly redesign and project delays can result. Accurate measurements and modeling of the pool fire environment will ultimately lower container costs by assuring that containers past the pool fire test on the first attempt. Experiments indicate that the object size or surface temperature of the container can play a role in determining local heat fluxes that are beyond the effects predicted from the simple radiative heat transfer laws. An analytical model described by Nicolette and Larson 1990 can be used to understand many of these effects. In this model a gray gas represents soot particles present in the flame structure. Close to the container surface, these soot particles are convectively and radiatively cooled and interact with incident energy from the surrounding fire. This cooler soot cloud effectively prevents some thermal radiation from reaching the container surface, reducing the surface heat flux below the value predicted by a transparent medium model. With some empirical constants, the model suggested by Nicolette and Larson can be used to more accurately simulate the pool fire environment. Properly formulated, the gray gas approaches also fast enough to be used with standard commercial computer codes to analyze shipping containers. To calibrate this type of model, accurate experimental measurements of radiative absorption coefficients, flame temperatures, and other parameters are necessary. A goal of the calorimeter measurements described here is to obtain such parameters so that a fast, useful design tool for large pool fires can be constructed.

  18. Experimental study on active cooling systems used for thermal management of high-power multichip light-emitting diodes.

    Kaya, Mehmet

    2014-01-01

    The objective of this study was to develop suitable cooling systems for high-power multichip LEDs. To this end, three different active cooling systems were investigated to control the heat generated by the powering of high-power multichip LEDs in two different configurations (30 and 2 × 15 W). The following cooling systems were used in the study: an integrated multi-fin heat sink design with a fan, a cooling system with a thermoelectric cooler (TEC), and a heat pipe cooling device. According to the results, all three systems were observed to be sufficient for cooling high-power LEDs. Furthermore, it was observed that the integrated multifin heat sink design with a fan was the most efficient cooling system for a 30 W high-power multichip LED. The cooling system with a TEC and 46 W input power was the most efficient cooling system for 2 × 15 W high-power multichip LEDs. PMID:25162058

  19. Investigation of Be/Cu joints via HHF tests of small-scale mockups

    Giniatulin, R.; Gervash, A.; Komarov, V.L.; Litunovsky, N.; Mazul, I.; Yablokov, N. [Efremov Inst., St. Petersburg (Russian Federation)

    1998-01-01

    Beryllium-copper (Be/Cu) joints in divertor components work under cyclic heat loads. To develop reliable joints small-scale mockups are fabricated by divertor technologies and tested under the divertor conditions. One of the critical damaging factors that exist in the divertor and have to be simulated is thermocyclic heat loads in the range of 1-15 MW/m{sup 2}. This work presents the divertor mockups that have beryllium tiles with different dimensions (5 x 5 - 44 x 44) mm{sup 2} brazed with copper alloy heat sink. The electron beam was used to braze these mockups so as to decrease the formation of brittle intermetallic layers. The description of mockups design, geometry of armour tiles and fabrication techniques are presented in the paper. The results of screening and thermocyclic tests of these mockups in the heat flux range of 2-12 MW/m{sup 2} with a number of cycles {approx}10{sup 3} are presented. The results of metallographic analysis are also presented. The results of fabrication and testing with small-scale mockups for first wall application are also described. (author)

  20. Source terms due to the activated corrosion products in primary cooling loops of ITER

    The paper deals with the Source Terms due to activated corrosion products escaping from a primary cooling loop of the ITER blanket following a Loss Of Cooling Accident (LOCA). Both in-vessel and out of vessel accident are considered. The assessment is based on the European multi-code methodological approach set-up to estimate the environmental releases of the activated corrosion/erosion products involved in the accident scenarios of a fusion machine. The approach is based on the following parameters: Radioactivity Inventory (RI), Process Source Terms (PST), and Environmental Source Terms (EST). Different codes have been used and compared to evaluate such parameters

  1. Differences Between Passive And Active Cooling Systems In Gender, Physiological Responses, Thermal Sensation And Productivity

    Schellen, Lisje; Loomans, Marcel; van Marken Lichtenbelt, Wouter;

    2011-01-01

    could occur due to application of low energy/exergy cooling systems, on human thermal comfort, physiological responses, and productivity. Furthermore, focus is on the differences between gender. This paper presents preliminary results obtained from experiments with four test subjects. To examine......) mixing ventilation (To=26oC), active cooling by convection through (2) mixing and (3) displacement ventilation, active cooling by radiation (4) through the ceiling and mixing ventilation (5) through the floor and mixing ventilation and (6) through the floor and displacement ventilation. Three female...... subjects visited the climate room on two occasions: (1) and (4). During the experiments both physiological responses and thermal sensation were measured. To assess the productivity and performance a ‘Remote Performance Measurement’ (RPM) method was used....

  2. Microelectromechanical System (MEMS) Device Being Developed for Active Cooling and Temperature Control

    Beach, Duane E.

    2003-01-01

    High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) using a Stirling thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface is being developed at the NASA Glenn Research Center to meet this need. The device can be used strictly in the cooling mode or can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly employ techniques routinely used in the semiconductor processing industry. Benefits of the MEMS cooler include scalability to fractions of a millimeter, modularity for increased capacity and staging to low temperatures, simple interfaces, limited failure modes, and minimal induced vibration. The MEMS cooler has potential applications across a broad range of industries such as the biomedical, computer, automotive, and aerospace industries. The basic capabilities it provides can be categorized into four key areas: 1) Extended environmental temperature range in harsh environments; 2) Lower operating temperatures for electronics and other components; 3) Precision spatial and temporal thermal control for temperature-sensitive devices; and 4) The enabling of microsystem devices that require active cooling and/or temperature control. The rapidly expanding capabilities of semiconductor processing in general, and microsystems packaging in particular, present a new opportunity to extend Stirling-cycle cooling to the MEMS domain. The comparatively high capacity and efficiency possible with a MEMS Stirling cooler provides a level of active cooling that is impossible at the microscale with current state-of-the-art techniques. The MEMS cooler technology builds on decades of research at Glenn on Stirling-cycle machines, and capitalizes on Glenn s emerging microsystems capabilities.

  3. Venus Mobile Explorer with RPS for Active Cooling: A Feasibility Study

    Leifer, Stephanie D.; Green, Jacklyn R.; Balint, Tibor S.; Manvi, Ram

    2009-01-01

    We present our findings from a study to evaluate the feasibility of a radioisotope power system (RPS) combined with active cooling to enable a long-duration Venus surface mission. On-board power with active cooling technology featured prominently in both the National Research Council's Decadal Survey and in the 2006 NASA Solar System Exploration Roadmap as mission-enabling for the exploration of Venus. Power and cooling system options were reviewed and the most promising concepts modeled to develop an assessment tool for Venus mission planners considering a variety of future potential missions to Venus, including a Venus Mobile Explorer (either a balloon or rover concept), a long-lived Venus static lander, or a Venus Geophysical Network. The concepts modeled were based on the integration of General Purpose Heat Source (GPHS) modules with different types of Stirling cycle heat engines for power and cooling. Unlike prior investigations which reported on single point design concepts, this assessment tool allows the user to generate either a point design or parametric curves of approximate power and cooling system mass, power level, and number of GPHS modules needed for a "black box" payload housed in a spherical pressure vessel.

  4. Performance evaluation of an active solar cooling system utilizing low cost plastic collectors and an evaporatively-cooled absorption chiller

    Lof, G. O.; Westhoff, M. A.; Karaki, S.

    1984-02-01

    During the summer of 1982, air conditioning in Solar House 3 at Colorado State University was provided by an evaporatively-cooled absorption chiller. The single-effect lithium bromide chiller is an experimental three-ton unit from which heat is rejected by direct evaporative cooling of the condenser and absorber walls, thereby eliminating the need for a separate cooling tower. Domestic hot water was also provided by use of a double-walled heat exchanger and 80-gal hot water tank. A schematic of the system is given. Objectives of the project were: (1) evaluation of system performance over the course of one cooling season in Fort Collins, Colorado; (2) optimization of system operation and control; (3) development of a TRNSYS compatible model of the chiller; and (4) determination of cooling system performance in several U.S. climates by use of the model.

  5. Status report on preliminary design activities for solar heating and cooling systems

    1978-05-01

    Information presented provides status and progress on the development of solar heating and cooling systems. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities as part of the contract requirements.

  6. Small Spacecraft Active Thermal Control: Micro-Vascular Composites Enable Small Satellite Cooling

    Ghosh, Alexander

    2016-01-01

    The Small Spacecraft Integrated Power System with Active Thermal Control project endeavors to achieve active thermal control for small spacecraft in a practical and lightweight structure by circulating a coolant through embedded micro-vascular channels in deployable composite panels. Typically, small spacecraft rely on small body mounted passive radiators to discard heat. This limits cooling capacity and leads to the necessity to design for limited mission operations. These restrictions severely limit the ability of the system to dissipate large amounts of heat from radios, propulsion systems, etc. An actively pumped cooling system combined with a large deployable radiator brings two key advantages over the state of the art for small spacecraft: capacity and flexibility. The use of a large deployable radiator increases the surface area of the spacecraft and allows the radiation surface to be pointed in a direction allowing the most cooling, drastically increasing cooling capacity. With active coolant circulation, throttling of the coolant flow can enable high heat transfer rates during periods of increased heat load, or isolate the radiator during periods of low heat dissipation.

  7. Ciguatoxins activate specific cold pain pathways to elicit burning pain from cooling

    Vetter, Irina; Touska, Filip; Hess, Andreas; Hinsbey, Rachel; Sattler, Simon; Lampert, Angelika; Sergejeva, Marina; Sharov, Anastasia; Collins, Lindon S; Eberhardt, Mirjam; Engel, Matthias; Cabot, Peter J.; Wood, John N; Vlachová, Viktorie; Reeh, Peter W.

    2012-01-01

    Ciguatoxins derived from fish lead to cold allodynia in humans, the perception of intense burning pain in response to mild cooling. A novel mouse model of ciguatoxin-induced cold allodynia reveals that ciguatoxin activates the TRPA1 thermosensitive ion channel to mediate pain perception.

  8. Feasibility of Actively Cooled Silicon Nitride Airfoil for Turbine Applications Demonstrated

    Bhatt, Ramakrishna T.

    2001-01-01

    Nickel-base superalloys currently limit gas turbine engine performance. Active cooling has extended the temperature range of service of nickel-base superalloys in current gas turbine engines, but the margin for further improvement appears modest. Therefore, significant advancements in materials technology are needed to raise turbine inlet temperatures above 2400 F to increase engine specific thrust and operating efficiency. Because of their low density and high-temperature strength and thermal conductivity, in situ toughened silicon nitride ceramics have received a great deal of attention for cooled structures. However, the high processing costs and low impact resistance of silicon nitride ceramics have proven to be major obstacles for widespread applications. Advanced rapid prototyping technology in combination with conventional gel casting and sintering can reduce high processing costs and may offer an affordable manufacturing approach. Researchers at the NASA Glenn Research Center, in cooperation with a local university and an aerospace company, are developing actively cooled and functionally graded ceramic structures. The objective of this program is to develop cost-effective manufacturing technology and experimental and analytical capabilities for environmentally stable, aerodynamically efficient, foreign-object-damage-resistant, in situ toughened silicon nitride turbine nozzle vanes, and to test these vanes under simulated engine conditions. Starting with computer aided design (CAD) files of an airfoil and a flat plate with internal cooling passages, the permanent and removable mold components for gel casting ceramic slips were made by stereolithography and Sanders machines, respectively. The gel-cast part was dried and sintered to final shape. Several in situ toughened silicon nitride generic airfoils with internal cooling passages have been fabricated. The uncoated and thermal barrier coated airfoils and flat plates were burner rig tested for 30 min without

  9. Experimental Study on Active Cooling Systems Used for Thermal Management of High-Power Multichip Light-Emitting Diodes

    KAYA, MEHMET

    2014-01-01

    The objective of this study was to develop suitable cooling systems for high-power multichip LEDs. To this end, three different active cooling systems were investigated to control the heat generated by the powering of high-power multichip LEDs in two different configurations (30 and 2 × 15 W). The following cooling systems were used in the study: an integrated multi-fin heat sink design with a fan, a cooling system with a thermoelectric cooler (TEC), and a heat pipe cooling device. According ...

  10. Neutron yields and emission rates in the forward direction for 50MeV/u 18O—ion on thick Be,Cu,Au targets

    LiGui-Sheng; ZhangTian-Mei; 等

    1997-01-01

    Total neutron yields and neutron emission rates in the forward direction for 50MeV/u 18O-ion on thick Be,Cu,Au targets have been measured using an activation technique.The results indicate that neutron yields and emission rates in the forward direction depend on the atomic number of target nuclei,i.e.the lighter target the greater neurtron yield and neutron emission rate.Meanwhile,the neutron yield of 18O-ion is greater than that of 12C-ion when target nucleus and incident energy per nucleon are identical.

  11. Management of water leaks on Tore Supra actively cooled fusion device

    Up to now, Tore Supra is the only fusion device fully equipped with actively cooled Plasma Facing Components (PFCs). In case of abnormal events during a plasma discharge, the PFCs could be submitted to a transient high power density (run away electrons) or to a continuous phenomena as local thermal flux induced by trapped suprathermal electrons or ions). It could lead to a degradation of the PFC integrity and in the worst case to a water leak occurrence. Such water leak has important consequence on the tokamak operation that concerns PFCs themselves, monitoring equipment located in the vacuum vessel or connected to the ports as RF antennas, diagnostics or pumping systems. Following successive water leak events (the most important water leak, that occurred in September 2002, is described in the paper), a large feedback experience has been gained on Tore supra since more than 15 years that could be useful to actively cooled next devices as W7X and ITER. (authors)

  12. Design and analysis of a plate-fin sandwich actively cooled structural panel

    Smith, L. M.

    1978-01-01

    The skin structure of hydrogen fueled hypersonic transport vehicles traveling at Mach 6 and above must be designed to withstand, for relatively long periods of time, the aerodynamic heating effects which are far more severe than those encountered by the supersonic aircraft of today. The use of conventional aircraft materials such as aluminum in combination with forced convection active cooling to accommodate aerodynamic heating is addressed. The basic active cooling concept consists of a stringer stiffened plate-fin sandwich. The sandwich surface is subjected to the aerodynamic heat flux which is transferred, via convection, to a coolant that is forced through the sandwich under pressure. The coolant, in turn, circulates in a closed loop through a hydrogen heat exchanger and back through the skin panel.

  13. Activities of passive cooling applications and simulation of innovative nuclear power plant design

    This paper gives a general insight on activities of the Turkish Atomic Energy Authority (TAEA) concerning passive cooling applications and simulation of innovative nuclear power plant design. The condensation mode of heat transfer plays an important role for the passive heat removal application in advanced water-cooled reactor systems. But it is well understood that the presence of noncondesable (NC) gases can greatly inhibit the condensation process due to the build up of NC gas concentration at the liquid/gas interface. The isolation condenser of passive containment cooling system of the simplified boiling water reactors is a typical application area of in-tube condensation in the presence of NC. The test matrix of the experimental investigation undertaken at the METU-CTF test facility (Middle East Technical University, Ankara) covers the range of parameters; Pn (system pressure) : 2-6 bar, Rev (vapor Reynolds number): 45,000-94,000, and Xi (air mass fraction): 0-52%. This experimental study is supplemented by a theoretical investigation concerning the effect of mixture flow rate on film turbulence and air mass diffusion concepts. Recently, TAEA participated to an international standard problem (OECD ISP-42) which covers a set of simulation of PANDA test facility (Paul Scherrer Institut-Switzerland) for six different phases including different natural circulation modes. The concept of condensation in the presence of air plays an important role for performance of heat exchangers, designed for passive containment cooling, which in turn affect the natural circulation behaviour in PANDA systems. (author)

  14. High heat flux actively cooled plasma facing components development, realisation and first results in Tore Supra

    The development, design, manufacture and testing of actively cooled high heat flux (HHF) plasma facing components (PFCs) has been an essential part of the Tore Supra programme towards long powerful tokamak operation. The Tore Supra PFC programme has culminated in the installation and operation of a toroidal pump limiter, since 2002, which already allowed to reach new world records in steady state operation (1 GJ injected in a 6 min discharge). The HHF PFCs development and manufacturing was achieved through a long lead development and industrialisation programme (about 10 years) marked out with a number of challenges. The major technical topics cope with bonding technology analysis involving an adequate material selection and procurement, repair processes development and implementation, development of destructive and non-destructive testing methods, and more generally industrialisation assessment. All these lessons are relevant to the ITER divertor PFCs manufacturing, although the technical solution adopted for Tore Supra (flat tiles concept) is different from the one proposed for the ITER divertor (monoblock concept). The routine operation of the actively cooled toroidal pumped limiter (TPL), capable to sustain up to 10 MW m-2 of nominal convected heat flux, is described. Up to now, the limiter fulfills its objectives in terms of heat exhaust. However, the thermographic monitoring exhibits unexpected behavior of the surface temperature. Particle exhaust control displays a complex pattern, due to the high fraction of the injected deuterium, which remains in the wall. The first experimental results with a full actively cooled wall gives access to ITER relevant information on wall conditioning, hydrogen plasma density and vacuum vessel inventory control, carbon erosion and redeposition and capability of in situ monitoring in a completely actively cooled environment

  15. Steady state performance test analysis of actively cooled extractor grids for SST-1 neutral beam injector

    Neutral beam injection (NBI) system is a workhorse to heat magnetically confined tokamak fusion plasma. The heart of any NBI system is an ion extractor system. Steady State Superconducting Tokamak-1 (SST-1) needs 0.5 MW of hydrogen beam power at 30 kV to raise the plasma ion temperature to ∼1 keV and 1.7 MW of hydrogen beam power at 55 kV for future upgradation. To meet this requirement, an ion extractor system consisting of three actively cooled grids has been designed, fabricated, and its performance test has been done at MARION test stand, IPP, Julich, Germany. During long pulse (14 s) operation, hydrogen ion beam of energy 31 MJ has been extracted at 41 kV. In this paper, we have presented detailed analysis of calorimetric data of actively cooled extractor grids and showed that by monitoring outlet water temperature, grid material temperature can be monitored for safe steady state operation of a NBI system. Steady state operation of NBI is the present day interest of fusion research. In the present experimental case, performance test analysis indicates that the actively cooled grids attain steady state heat removal condition and the grid material temperature rise is ∼18 deg. C and saturates after 10 s of beam pulse.

  16. Rapid cooling rates at an active mid-ocean ridge from zircon thermochronology

    Schmitt, Axel K.; Perfit, Michael R.; Rubin, Kenneth H.; Stockli, Daniel F.; Smith, Matthew C.; Cotsonika, Laurie A.; Zellmer, Georg F.; Ridley, W. Ian; Lovera, Oscar M.

    2011-02-01

    Oceanic spreading ridges are Earth's most productive crust generating environment, but mechanisms and rates of crustal accretion and heat loss are debated. Existing observations on cooling rates are ambiguous regarding the prevalence of conductive vs. convective cooling of lower oceanic crust. Here, we report the discovery and dating of zircon in mid-ocean ridge dacite lavas that constrain magmatic differentiation and cooling rates at an active spreading center. Dacitic lavas erupted on the southern Cleft segment of the Juan de Fuca ridge, an intermediate-rate spreading center, near the intersection with the Blanco transform fault. Their U-Th zircon crystallization ages (29.3 - 4.6 + 4.8 ka; 1σ standard error s.e.) overlap with the (U-Th)/He zircon eruption age (32.7 ± 1.6 ka) within uncertainty. Based on similar 238U- 230Th disequilibria between southern Cleft dacite glass separates and young mid-ocean ridge basalt (MORB) erupted nearby, differentiation must have occurred rapidly, within ~ 10-20 ka at most. Ti-in-zircon thermometry indicates crystallization at 850-900 °C and pressures > 70-150 MPa are calculated from H 2O solubility models. These time-temperature constraints translate into a magma cooling rate of ~ 2 × 10 - 2 °C/a. This rate is at least one order-of-magnitude faster than those calculated for zircon-bearing plutonic rocks from slow spreading ridges. Such short intervals for differentiation and cooling can only be resolved through uranium-series ( 238U- 230Th) decay in young lavas, and are best explained by dissipating heat convectively at high crustal permeability.

  17. Experimental investigation on activated carbon-ethanol pair for solar powered adsorption cooling applications

    El-Sharkawy, I.I. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen 6-1, Kasuga-shi, Fukuoka 816-8580 (Japan); Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, El-Mansoura (Egypt); Saha, B.B.; Koyama, S. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga-koen 6-1, Kasuga-shi, Fukuoka 816-8580 (Japan); He, J.; Ng, K.C.; Yap, C. [Department of Mechanical Engineering, National University of Singapore, 10 Kent Ridge Crescent (Singapore)

    2008-12-15

    Adsorption equilibrium uptake of ethanol onto a highly porous activated carbon based adsorbent, namely Maxsorb III, has been experimentally investigated using a thermo-gravimetric analyzer (TGA) unit over adsorption temperatures ranging from 20 to 60 C. The Dubinin-Astakhov (D-A) equation has been used to correlate the experimental data. Isosteric heat of adsorption is also estimated by using the Clausius-Clapeyron equation. Employing a thermodynamically equilibrium model, the performance of the ideal adsorption cooling cycle has also been studied and compared to that of activated carbon fiber (ACF)-ethanol pair. Experimental results show that Maxsorb III can adsorb up to 1.2 kg of ethanol per kilogram of adsorbent. Theoretical calculations show that, the Maxsorb III-ethanol adsorption cycle can achieve a specific cooling effect of about 420 kJ kg{sup -1} at an evaporator temperature of 7 C along with a heat source of temperature 80 C and thus the pair is recommended for solar cooling applications. (author)

  18. Resistance of Alkali Activated Water-Cooled Slag Geopolymer to Sulphate Attack

    S. A. Hasanein

    2011-06-01

    Full Text Available Ground granulated blast furnace slag is a finely ground, rapidly chilled aluminosilicate melt material that is separated from molten iron in the blast furnace as a by-product. Rapid cooling results in an amorphous or a glassy phase known as GGBFS or water cooled slag (WCS. Alkaline activation of latent hydraulic WCS by sodium hydroxide and/or sodium silicate in different ratios was studied. Curing was performed under 100 % relative humidity and at a temperature of 38°C. The results showed that mixing of both sodium hydroxide and sodium silicate in ratio of 3:3 wt.,% is the optimum one giving better mechanical as well as microstructural characteristics as compared with cement mortar that has various cement content (cement : sand were 1:3 and 1:2. Durability of the water cooled slag in 5 % MgSO4 as revealed by better microstructure and high resistivity-clarifying that activation by 3:3 sodium hydroxide and sodium silicate, respectively is better than using 2 and 6 % of sodium hydroxide.

  19. Transport and deposition of activation products in a helium cooled fusion power plant

    The transport and deposition of neutron activation products in a helium cooled tokamak fusion power plant are investigated. Stainless steel is used as coolant channel material for a helium/steam system. The important gamma emitting nuclides 56Mn, 54Mn, 57Co, 58Co, 60Co, 51Cr, and 99Mo are considered. The dominant release mechanism identified is direct daughter recoil emission from (n,x) type reactions. Corrosion and evaporation are discussed. The radionuclide inventory released by these mechanisms is predicted to exceed 1 x 104 Ci for a reference reactor design after only several days of operation, and approach 3.5 x 104 Ci in equilibrium. A mass transport model is then used to predict the deposition pattern of this inventory in the reactor cooling system

  20. Evaluation of a large capacity heat pump concept for active cooling of hypersonic aircraft structure

    Pagel, L. L.; Herring, R. L.

    1978-01-01

    Results of engineering analyses assessing the conceptual feasibility of a large capacity heat pump for enhancing active cooling of hypersonic aircraft structure are presented. A unique heat pump arrangement which permits cooling the structure of a Mach 6 transport to aluminum temperatures without the aid of thermal shielding is described. The selected concept is compatible with the use of conventional refrigerants, with Freon R-11 selected as the preferred refrigerant. Condenser temperatures were limited to levels compatible with the use of conventional refrigerants by incorporating a unique multipass condenser design, which extracts mechanical energy from the hydrogen fuel, prior to each subsequent pass through the condenser. Results show that it is technically feasible to use a large capacity heat pump in lieu of external shielding. Additional analyses are required to optimally apply this concept.

  1. Source terms due to the activated corrosion products in primary cooling loops of ITER

    This paper deals with the source terms due to the escape of activated corrosion products from a first wall or shielding blanket primary cooling loop of the international thermonuclear experimental reactor (ITER) machine following a loss of coolant accident (LOCA). The assessment is based on the European multi-code methodological approach set up to estimate the environmental releases of the activated corrosion/erosion products involved in accident scenarios of a fusion machine. The radioactive inventories (RIs) associated with the activation products have been estimated via the ANITA inventory code, using updated cross-section and decay data libraries based on EAF-3 activation data. The process source terms (PSTs) relevant to the LOCAs are estimated by considering mechanisms leading to RI mobilization (e.g. corrosion/erosion). The impact of the main operating parameters of the primary cooling loops is assessed. The FUMO codes have been used to estimate the thermal hydraulic conditions inside the containment. The PST transport and deposition in the containment are evaluated by the NAUA code in order to assess the released fraction from the last containment (reactor building). (orig.)

  2. Requirements for helium cooled pebble bed blanket and R and D activities

    Carloni, D., E-mail: dario.carloni@kit.edu; Boccaccini, L.V.; Franza, F.; Kecskes, S.

    2014-10-15

    This work aims to give an outline of the design requirements of the helium cooled pebble bed (HCPB) blanket and its associated R and D activities. In DEMO fusion reactor the plasma facing components have to fulfill several requirements dictated by safety and process sustainability criteria. In particular the blanket of a fusion reactor shall transfer the heat load coming from the plasma to the cooling system and also provide tritium breeding for the fuel cycle of the machine. KIT has been investigating and developed a helium-cooled blanket for more than three decades: the concept is based on the adoption of separated small lithium orthosilicate (tritium breeder) and beryllium (neutron multiplier) pebble beds, i.e. the HCPB blanket. One of the test blanket modules of ITER will be a HCPB type, aiming to demonstrate the soundness of the concept for the exploitation in future fusion power plants. A discussion is reported also on the development of the design criteria for the blanket to meet the requirements, such as tritium environmental release, also with reference to the TBM. The selection of materials and components to be used in a unique environment as the Tokamak of a fusion reactor requires dedicated several R and D activities. For instance, the performance of the coolant and the tritium self-sufficiency are key elements for the realization of the HCPB concept. Experimental campaigns have been conducted to select the materials to be used inside the solid breeder blanket and R and D activities have been carried out to support the design. The paper discusses also the program of future developments for the realization of the HCPB concept, also focusing to the specific campaigns necessary to qualify the TBM for its implementation in the ITER machine.

  3. Requirements for helium cooled pebble bed blanket and R and D activities

    This work aims to give an outline of the design requirements of the helium cooled pebble bed (HCPB) blanket and its associated R and D activities. In DEMO fusion reactor the plasma facing components have to fulfill several requirements dictated by safety and process sustainability criteria. In particular the blanket of a fusion reactor shall transfer the heat load coming from the plasma to the cooling system and also provide tritium breeding for the fuel cycle of the machine. KIT has been investigating and developed a helium-cooled blanket for more than three decades: the concept is based on the adoption of separated small lithium orthosilicate (tritium breeder) and beryllium (neutron multiplier) pebble beds, i.e. the HCPB blanket. One of the test blanket modules of ITER will be a HCPB type, aiming to demonstrate the soundness of the concept for the exploitation in future fusion power plants. A discussion is reported also on the development of the design criteria for the blanket to meet the requirements, such as tritium environmental release, also with reference to the TBM. The selection of materials and components to be used in a unique environment as the Tokamak of a fusion reactor requires dedicated several R and D activities. For instance, the performance of the coolant and the tritium self-sufficiency are key elements for the realization of the HCPB concept. Experimental campaigns have been conducted to select the materials to be used inside the solid breeder blanket and R and D activities have been carried out to support the design. The paper discusses also the program of future developments for the realization of the HCPB concept, also focusing to the specific campaigns necessary to qualify the TBM for its implementation in the ITER machine

  4. Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor

    Xingtuan Yang; Yanfei Sun; Huaiming Ju; Shengyao Jiang

    2014-01-01

    After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was ca...

  5. Active Cooling and Thermal Management of a Downhole Tool Electronics Section

    Soprani, Stefano; Engelbrecht, Kurt; Just Nørgaard, Anders

    2015-01-01

    High Temperature (HT) wellbores represent one of today’s biggest challenges for the oil and gas industry. The majority of well intervention wireline tools contain temperature sensitive electronics that are not able to withstand the high temperatures of HT wellbores (> 150 °C), for an extended per...... contact resistances were minimized and thermally insulating foam protected the refrigerated microenvironment from the hot surroundings....... combines active and passive cooling techniques, aiming at an efficient thermal management, preserving the tool compactness and avoiding the use of moving parts. Thermoelectric coolers were used to transfer the dissipated heat from the temperature-sensitive electronics to the external environment. Thermal...

  6. A nonventing cooling system for space environment extravehicular activity, using radiation and regenerable thermal storage

    Bayes, Stephen A.; Trevino, Luis A.; Dinsmore, Craig E.

    1988-01-01

    This paper outlines the selection, design, and testing of a prototype nonventing regenerable astronaut cooling system for extravehicular activity space suit applications, for mission durations of four hours or greater. The selected system consists of the following key elements: a radiator assembly which serves as the exterior shell of the portable life support subsystem backpack; a layer of phase change thermal storage material, n-hexadecane paraffin, which acts as a regenerable thermal capacitor; a thermoelectric heat pump; and an automatic temperature control system. The capability for regeneration of thermal storage capacity with and without the aid of electric power is provided.

  7. Langmuir probes design for the actively cooled divertor baffle in WEST

    Cacace, Maurizio, E-mail: maurizio.cacace@hotmail.it [CREATE, Universitàdi Napoli Federico II, Dipartimento di Ingegneria Industriale, P.le Tecchio 80, 80125 Napoli (Italy); Batal, Tristan; Corre, Yann [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France); Di Gironimo, Giuseppe, E-mail: giuseppe.digironimo@unina.it [CREATE, Universitàdi Napoli Federico II, Dipartimento di Ingegneria Industriale, P.le Tecchio 80, 80125 Napoli (Italy); Gunn, Jamie P.; Pascal, Jean-Yves; Salasca, Sophie [CEA, IRFM, F-13108 Saint-Paul-Lez-Durance (France)

    2015-04-15

    Highlights: • Design of probes has followed an iterative approach. • CAD activity and FE thermo-mechanical analyses were performed in order to optimize the design. • The present design of Langmuir probes guarantees thermal contact efficiency and geometric simplicity. - Abstract: The WEST project (W-Environment in Steady-State Tokamak) aims to transform the Tore Supra limiter configuration to an x-point divertor, providing a test bed for ITER-like plasma-facing components (actively cooled W monoblocs) under high heat flux, steady-state plasma irradiation. The lower divertor includes an actively cooled, W-coated CuCrZr baffle to provide neutral compression and improve particle exhaust. As part of the new diagnostic equipment of Tore Supra within WEST project, a set of Langmuir probes will find place on the baffle in order to provide plasma flux and electron temperature measurements for physics studies and real-time machine protection functions during steady-state discharges. On the baffle top surface, irradiation coming from the plasma, energetic ripple-ions losses, photons and energetic neutrals from charge exchange reactions produce power fluxes up to 3 MW/m{sup 2}, representing a challenge for the Langmuir probes operating conditions. In this paper Copper–Chrome–Zirconium (CuCrZr) cylindrical probe concept design is proposed. Finite element thermo-mechanical analysis (FEA) confirmed the consistency of this solution under the steady-state plasma condition in the worst case (highest thermal load)

  8. Langmuir probes design for the actively cooled divertor baffle in WEST

    Highlights: • Design of probes has followed an iterative approach. • CAD activity and FE thermo-mechanical analyses were performed in order to optimize the design. • The present design of Langmuir probes guarantees thermal contact efficiency and geometric simplicity. - Abstract: The WEST project (W-Environment in Steady-State Tokamak) aims to transform the Tore Supra limiter configuration to an x-point divertor, providing a test bed for ITER-like plasma-facing components (actively cooled W monoblocs) under high heat flux, steady-state plasma irradiation. The lower divertor includes an actively cooled, W-coated CuCrZr baffle to provide neutral compression and improve particle exhaust. As part of the new diagnostic equipment of Tore Supra within WEST project, a set of Langmuir probes will find place on the baffle in order to provide plasma flux and electron temperature measurements for physics studies and real-time machine protection functions during steady-state discharges. On the baffle top surface, irradiation coming from the plasma, energetic ripple-ions losses, photons and energetic neutrals from charge exchange reactions produce power fluxes up to 3 MW/m2, representing a challenge for the Langmuir probes operating conditions. In this paper Copper–Chrome–Zirconium (CuCrZr) cylindrical probe concept design is proposed. Finite element thermo-mechanical analysis (FEA) confirmed the consistency of this solution under the steady-state plasma condition in the worst case (highest thermal load)

  9. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    Grosman, A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2004-07-01

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m{sup 2} of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m{sup 2} TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  10. Actively cooled plasma facing components in Tore Supra: From material and design to operation

    Magaud, Ph. [Association Euratom-CEA, DSM/DRFC/SIPP, CEA-Cadarache, F-13108 St-Paul-Lez-Durance (France)]. E-mail: philippe.magaud@cea.fr; Monier-Garbet, P. [Association Euratom-CEA, DSM/DRFC/SIPP, CEA-Cadarache, F-13108 St-Paul-Lez-Durance (France); Travere, J.M. [Association Euratom-CEA, DSM/DRFC/SIPP, CEA-Cadarache, F-13108 St-Paul-Lez-Durance (France); Grosman, A. [Association Euratom-CEA, DSM/DRFC/SIPP, CEA-Cadarache, F-13108 St-Paul-Lez-Durance (France)

    2007-05-31

    In current fusion devices, the components located in front of plasma, the so-called plasma facing components (PFCs), need to sustain severe constraints such as high thermal flux (several MW m{sup -2}), erosion and flux of particles. Feedback from these challenging components is essential for the success of the next generation of components, in particular in term of manufacturing or handling intense heat loads. Tore Supra actively cooled high heat flux PFCs are able to sustain up to 10 MW m{sup -2} during long plasma pulses. They are at present the only ones in operation in a fusion device. They are described in details from design (including the testing programme used for concept validation) to operation. Lessons learned from the industrialization programme, which could be essential for ITER, will be presented. Finally, the experimental feedback with actively cooled walls, including in situ monitoring to guarantee plasma facing component safety, will be summarized. Another very important feature has been noticed, namely the in vessel progressive uptake of hydrogen, a likely source of concern for ITER.

  11. High heat flux actively cooled plasma facing components development, realization and first results in Tore Supra

    The development, design, manufacture and testing of actively cooled high heat flux plasma facing components (PFC) has been an essential stage towards long powerful tokamak operations for Tore-Supra, it lasted about 10 years. This paper deals with the toroidal pumped limiter (TPL) that is able to sustain up to 10 MW/m2 of nominal heat flux. This device is based on hardened copper alloy heat sink structures covered by a carbon fiber composite armour, it resulted in the manufacturing of 600 elementary components, called finger elements, to achieve the 7.6 m2 TPL. This assembly has been operating in Tore-Supra since spring 2002. Some difficulties occurred during the manufacturing phase, the valuable industrial experience is summarized in the section 2. The permanent monitoring of PFC surface temperature all along the discharge is performed by a set of 6 actively cooled infrared endoscopes. The heat flux monitoring and control issue but also the progress made in our understanding of the deuterium retention in long discharges are described in the section 3. (A.C.)

  12. Nondestructive test of brazed cooling tubes of prototype bolometer camera housing using active infrared thermography.

    Tahiliani, Kumudni; Pandya, Santosh P; Pandya, Shwetang; Jha, Ratneshwar; Govindarajan, J

    2011-01-01

    The active infrared thermography technique is used for assessing the brazing quality of an actively cooled bolometer camera housing developed for steady state superconducting tokamak. The housing is a circular pipe, which has circular tubes vacuum brazed on the periphery. A unique method was adopted to monitor the temperature distribution on the internal surface of the pipe. A stainless steel mirror was placed inside the pipe and the reflected IR radiations were viewed using an IR camera. The heat stimulus was given by passing hot water through the tubes and the temperature distribution was monitored during the transient phase. The thermographs showed a significant nonuniformity in the brazing with a contact area of around 51%. The thermography results were compared with the x-ray radiographs and a good match between the two was observed. Benefits of thermography over x-ray radiography testing are emphasized. PMID:21280850

  13. Actively cooled guard limiters for Tore Supra ICRH and LHCD antennas

    The new limiters have been designed identical for ICRH and LHCD Tore Supra antennas with the objective to operate on Tore Supra at high power levers, up to 25 MW (15 MW convective and 10 MW radiative) with long pulse duration shots (1000 s). In the new design, the limiters are installed on the antenna from the inside of the vessel allowing an exchange surface larger than the previous type, increasing consequently the performance. Thanks also to the development made for the future TPL, the new limiter technology is upgraded using a concept based on CFC (Carbon Fibre Composite) shaped tiles, intimately linked to the actively water cooled heat sink by Active Metal Casting (AMC) process, developed by Plansee Company. (author)

  14. Actively cooled guard limiters for Tore Supra ICRH and LHCD antennas

    Agarici, G.; Beaumont, B.; Bibet, Ph.; Bremond, S.; Delaplanche, J.M.; Garampon, L.; Ladurelle, L.; Lombard, G.; Mollard, P.; Patterlini, C. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Huber, T.; Ploechl, L. [PLANSEE Aktiengesellschaft, Reutte (Austria)

    1998-07-01

    The new limiters have been designed identical for ICRH and LHCD Tore Supra antennas with the objective to operate on Tore Supra at high power levers, up to 25 MW (15 MW convective and 10 MW radiative) with long pulse duration shots (1000 s). In the new design, the limiters are installed on the antenna from the inside of the vessel allowing an exchange surface larger than the previous type, increasing consequently the performance. Thanks also to the development made for the future TPL, the new limiter technology is upgraded using a concept based on CFC (Carbon Fibre Composite) shaped tiles, intimately linked to the actively water cooled heat sink by Active Metal Casting (AMC) process, developed by Plansee Company. (author)

  15. A high-fat diet impairs cooling-evoked brown adipose tissue activation via a vagal afferent mechanism.

    Madden, Christopher J; Morrison, Shaun F

    2016-08-01

    In dramatic contrast to rats on a control diet, rats maintained on a high-fat diet (HFD) failed to activate brown adipose tissue (BAT) during cooling despite robust increases in their BAT activity following direct activation of their BAT sympathetic premotor neurons in the raphe pallidus. Cervical vagotomy or blockade of glutamate receptors in the nucleus of the tractus solitarii (NTS) reversed the HFD-induced inhibition of cold-evoked BAT activity. Thus, a HFD does not prevent rats from mounting a robust, centrally driven BAT thermogenesis; however, a HFD does alter a vagal afferent input to NTS neurons, thereby preventing the normal activation of BAT thermogenesis to cooling. These results, paralleling the absence of cooling-evoked glucose uptake in the BAT of obese humans, reveal a neural mechanism through which consumption of a HFD contributes to reduced energy expenditure and thus to weight gain. PMID:27354235

  16. Scaling model for prediction of radionuclide activity in cooling water using a regression triplet technique

    The decommissioning of the nuclear power plant (NPP) A1 Jaslovske Bohunice (Slovakia) is a complicated set of problems that is highly demanding both technically and financially. The basic goal of the decommissioning process is the total elimination of radioactive materials from the nuclear power plant area, and radwaste treatment to a form suitable for its safe disposal. The initial conditions of decommissioning also include elimination of the operational events, preparation and transport of the fuel from the plant territory, radiochemical and physical-chemical characterization of the radioactive wastes. One of the problems was and still is the processing of the liquid radioactive wastes. Such media is also the cooling water of the long-term storage of spent fuel. A suitable scaling model for predicting the activity of hard-to-detect radionuclides 239,240Pu, 90Sr and summary beta in cooling water using a regression triplet technique has been built using the regression triplet analysis and regression diagnostics. (author)

  17. Experiments on FTU with an actively water cooled liquid lithium limiter

    In order to prevent the overheating of the liquid Li surface and the consequent Li evaporation for T > 500 °C, an advanced version of the liquid lithium limiter has been realized and installed on FTU. This new system, named Cooled Lithium Limiter (CLL), has been optimized to demonstrate the lithium limiter capability to sustain thermal loads as high as 10 MW/m2 with up to 5 s of plasma pulse duration. The CLL operates with an actively cooled system with water circulation at the temperature of about 200 °C, for heating lithium up to the melting point and for the heat removal during the plasma discharges. To characterize CLL during discharges, a fast infrared camera and the spectroscopic signals from Li and D atom emission have been used. The experiments analyzed so far and simulated by ANSYS code, point out that heat loads as high as 2 MW/m2 for 1.5 s have been withstood without problems

  18. Experiments on FTU with an actively water cooled liquid lithium limiter

    Mazzitelli, G., E-mail: giuseppe.mazzitelli@enea.it [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, C.P. 65-00044 Frascati, Rome (Italy); Apicella, M.L.; Apruzzese, G.; Crescenzi, F.; Iannone, F.; Maddaluno, G. [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, C.P. 65-00044 Frascati, Rome (Italy); Pericoli-Ridolfini, V. [Associazione EURATOM-ENEA sulla Fusione, CREATE, Università di Napoli Federico II, 80125 Napoli (Italy); Roccella, S.; Reale, M.; Viola, B. [Associazione EURATOM-ENEA sulla Fusione, C.R. Frascati, C.P. 65-00044 Frascati, Rome (Italy); Lyublinski, I.; Vertkov, A. [JSC “RED STAR”, Moscow (Russian Federation)

    2015-08-15

    In order to prevent the overheating of the liquid Li surface and the consequent Li evaporation for T > 500 °C, an advanced version of the liquid lithium limiter has been realized and installed on FTU. This new system, named Cooled Lithium Limiter (CLL), has been optimized to demonstrate the lithium limiter capability to sustain thermal loads as high as 10 MW/m{sup 2} with up to 5 s of plasma pulse duration. The CLL operates with an actively cooled system with water circulation at the temperature of about 200 °C, for heating lithium up to the melting point and for the heat removal during the plasma discharges. To characterize CLL during discharges, a fast infrared camera and the spectroscopic signals from Li and D atom emission have been used. The experiments analyzed so far and simulated by ANSYS code, point out that heat loads as high as 2 MW/m{sup 2} for 1.5 s have been withstood without problems.

  19. Thermodynamic assessment of active cooling/heating methods for lithium-ion batteries of electric vehicles in extreme conditions

    The battery cooling/heating with active methods is required for EVs (electric vehicles) in the extreme temperature conditions. This work presents a new active battery cooling/heating method based on PCS (phase change slurry) cycle. Two typical often used active cooling/heating methods so-called the direct cabin air blow and refrigerant circulation are also illustrated in detail. The thermodynamic assessment is conducted on these battery active cooling/heating methods with both of 1st Law and 2nd Law analysis. The variations of extra thermal load to the vehicle air-conditioning system are investigated as changes of ambient temperature, humidity and thermal load for the direct cabin air blow method. The simulation results show that the direct cabin air blow method causes more extra thermal load to the air-conditioning system without considering the cabin ventilation effect. The PCS cycle method performs higher exergy efficiency than that of using refrigerant circulation method. - Highlights: • An active EV battery cooling/heating method based on PCS cycle is proposed. • Thermodynamic assessments are performed for the proposed methods. • The sensitivities of operation conditions to the methods are investigated

  20. Swiss activities in the field of gas-cooled reactors in 1983

    Swiss industrial companies and the Swiss Federal Institute for Reactor Research (EIR) have been involved in the development of Gas Cooled Reactors since 1968. A significant contribution has been made to the HHT-Project (High Temperature Reactor with a Helium Turbine) in close cooperation with German partners between 1973 and 1982. Both the Swiss and the German partners intend to continue the collaboration within the framework of the German project HTR-500. A four year-working program for the Swiss partners was established in the beginning of 1983. However, since the request for financial support addressed to the Swiss Government has not yet been granted, work has been performed only to a limited extent so far. The activities of the Swiss partners in 1983 are briefly presented in the report

  1. A totally active scintillator calorimeter for the Muon Ionization Cooling Experiment (MICE). Design and construction

    Asfandiyarov, R

    2013-01-01

    The Electron-Muon Ranger (EMR) is a totally active scintillator detector to be installed in the muon beam of the Muon Ionization Cooling Experiment (MICE) [1] – the main R&D project for the future neutrino factory. It is aimed at measuring the properties of the low energy beam composed of muons, electrons and pions, performing the identification particle by particle. The EMR is made of 48 stacked layers alternately measuring the X- and the Y-coordinate. Each layer consists of 59 triangular scintillator bars. It is shown that the granularity of the detector permits to identify tracks and to measure particle ranges and shower shapes. The read-out is based on FPGA custom made electronics and commercially available modules. Currently it is being built at the University of Geneva.

  2. REMOVING COOL CORES AND CENTRAL METALLICITY PEAKS IN GALAXY CLUSTERS WITH POWERFUL ACTIVE GALACTIC NUCLEUS OUTBURSTS

    Recent X-ray observations of galaxy clusters suggest that cluster populations are bimodally distributed according to central gas entropy and are separated into two distinct classes: cool core (CC) and non-cool core (NCC) clusters. While it is widely accepted that active galactic nucleus (AGN) feedback plays a key role in offsetting radiative losses and maintaining many clusters in the CC state, the origin of NCC clusters is much less clear. At the same time, a handful of extremely powerful AGN outbursts have recently been detected in clusters, with a total energy ∼1061-1062 erg. Using two-dimensional hydrodynamic simulations, we show that if a large fraction of this energy is deposited near the centers of CC clusters, which is likely common due to dense cores, these AGN outbursts can completely remove CCs, transforming them to NCC clusters. Our model also has interesting implications for cluster abundance profiles, which usually show a central peak in CC systems. Our calculations indicate that during the CC to NCC transformation, AGN outbursts efficiently mix metals in cluster central regions and may even remove central abundance peaks if they are not broad enough. For CC clusters with broad central abundance peaks, AGN outbursts decrease peak abundances, but cannot effectively destroy the peaks. Our model may simultaneously explain the contradictory (possibly bimodal) results of abundance profiles in NCC clusters, some of which are nearly flat, while others have strong central peaks similar to those in CC clusters. A statistical analysis of the sizes of central abundance peaks and their redshift evolution may shed interesting insights on the origin of both types of NCC clusters and the evolution history of thermodynamics and AGN activity in clusters.

  3. Tractor Mechanics. Maintaining and Servicing the Cooling System, Learning Activity Packages 34-40; Maintaining and Servicing Hydraulic Systems, Learning Activity Packages 41-48.

    Clemson Univ., SC. Vocational Education Media Center.

    This series of learning activity packages focuses on two areas of tractor mechanics: (1) maintaining and servicing the cooling system and (2) maintaining and servicing hydraulic systems. Each of the fifteen illustrated learning activity packages follows a typical format: introduction, directions, objectives, learning activities, tools and…

  4. Methodology to determine cost and performance goals for active solar cooling systems

    Warren, M. L.; Wahlig, M.

    1981-11-01

    Systems analysis is used to calculate the 20 yr. present value of energy savings of solar cooling systems located in Texas, Arizona, Florida, and Washington, DC, and methods of solar system development to meet the cost goals of economic operation are outlined. Solar cooling systems are projected to begin commercial entry in 1986 and reach 20% of the total cooling market by the year 2000, producing 0.14 quads of displaced energy. A numerical simulation was carried out for both residential and commercial solar cooling units with consideration for system cost goals, cost goals per unit collector area, and the cost goals per ton of cooling. System size was targeted as a 3 ton residential chiller and a 25 ton commercial absorption cooling unit. The costs for volume production are provided, along with trends for an incrementally decreasing need for tax incentives, ending in about 1994

  5. Ciguatoxins activate specific cold pain pathways to elicit burning pain from cooling.

    Vetter, Irina; Touska, Filip; Hess, Andreas; Hinsbey, Rachel; Sattler, Simon; Lampert, Angelika; Sergejeva, Marina; Sharov, Anastasia; Collins, Lindon S; Eberhardt, Mirjam; Engel, Matthias; Cabot, Peter J; Wood, John N; Vlachová, Viktorie; Reeh, Peter W; Lewis, Richard J; Zimmermann, Katharina

    2012-10-01

    Ciguatoxins are sodium channel activator toxins that cause ciguatera, the most common form of ichthyosarcotoxism, which presents with peripheral sensory disturbances, including the pathognomonic symptom of cold allodynia which is characterized by intense stabbing and burning pain in response to mild cooling. We show that intraplantar injection of P-CTX-1 elicits cold allodynia in mice by targeting specific unmyelinated and myelinated primary sensory neurons. These include both tetrodotoxin-resistant, TRPA1-expressing peptidergic C-fibres and tetrodotoxin-sensitive A-fibres. P-CTX-1 does not directly open heterologously expressed TRPA1, but when co-expressed with Na(v) channels, sodium channel activation by P-CTX-1 is sufficient to drive TRPA1-dependent calcium influx that is responsible for the development of cold allodynia, as evidenced by a large reduction of excitatory effect of P-CTX-1 on TRPA1-deficient nociceptive C-fibres and of ciguatoxin-induced cold allodynia in TRPA1-null mutant mice. Functional MRI studies revealed that ciguatoxin-induced cold allodynia enhanced the BOLD (Blood Oxygenation Level Dependent) signal, an effect that was blunted in TRPA1-deficient mice, confirming an important role for TRPA1 in the pathogenesis of cold allodynia. PMID:22850668

  6. Thermo Active Building Systems Using Building Mass To Heat and Cool

    Olesen, Bjarne W.

    2012-01-01

    Using the thermal storage capacity of the concrete slabs between each floor in multistory buildings to heat or cool is a trend that began in the early 1990s in Switzerland.1,2 Pipes carrying water for heating and cooling are embedded in the center of the concrete slab. In central Europe (Germany...

  7. Totally Active Scintillator Tracker-Calorimeter for the Muon Ionization Cooling Experiment

    Asfandiyarov, Ruslan

    2014-09-31

    The recent discoveries in particle physics, the Higgs Boson and neutrino oscillations, voiced the need for new machines that can provide higher intensities, energy and precision. To study the neutrino oscillations in great details and to access new physics, a Neutrino Factory stands as an ultimate tool that offers a high intensity, well understood neutrino beam. On the other hand, a Muon Collider is indispensable for better understanding of a Higgs physics. Both machines share similar ingredients and one of them, that is essential to achieve high luminosity of the beams, is beam cooling. And the only feasible method to achieve cooling of a muons beam is based on ionization. An R&D project was established to verify a possibility of such a cooling, Muon Ionization Cooling Experiment (MICE). Its purpose is to build a cooling cell capable of cooling a muon beam by 10% and measure the effect (the cooling effect is attributed to a reduction of beam emittance) with an absolute precision of 0.1%. This is achieve...

  8. Particle exhaust of helium plasmas with actively cooled outboard pump limiter on Tore Supra

    The superconducting tokamak Tore Supra was designed for long-pulse (30-s) high input power operation. Here observations on the particle-handling characteristics of the actively cooled modular outboard pump limiter (OPL) are presented for helium discharges. The important experimental result was that a modest pumping speed (1 m3/s) of the OPL turbomolecular pump (TMP) provided background helium exhaust. This result came about due to a well-conditioned vessel wall with helium discharges that caused no wall outgasing. The particle accountability in these helium discharges was excellent, and the well-conditioned wall did not play a significant role in the particle balance. The helium density control, 25% density drop with OPL exhaust efficiency of ∼1%, was possible with TMP although this may not be the case with reactive gases such as deuterium. The observed quadratic increase of the OPL neutral pressure with helium density was consistent with an improvement of the particle control with increasing plasma density

  9. Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor

    Xingtuan Yang

    2014-01-01

    Full Text Available After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was carried out based on a one-dimensional mathematical model for steam generator and steam pipe of start-up loop to achieve safety and reliability. The results show that steam generator should be discharged and precooled; otherwise, boiling will arise and introduce a cold shock to the boiling tubes and tube sheet when coolant began to circulate prior to the helium. Additionally, in avoiding heat shock caused by the sudden load of helium, the helium circulation should be restricted to start with an extreme low flow rate; meanwhile, the coolant of steam generator (water should have flow rate as large as possible. Finally, a four-step procedure with precooling process of steam generator was recommended; sensitive study for the main parameters was conducted.

  10. Damage of actively cooled plasma facing components of magnetic confinement controlled fusion machines

    Chevet, G. [Association Euratom-CEA, DSM/DRFC, CEA Cadarache, Saint-Paul-Lez-Durance (France)], E-mail: gaelle.chevet@cea.fr; Schlosser, J. [Association Euratom-CEA, DSM/DRFC, CEA Cadarache, Saint-Paul-Lez-Durance (France); Martin, E.; Herb, V.; Camus, G. [Universite Bordeaux 1, UMR 5801 (CNRS-SAFRAN-CEA-UB1), Laboratoire des Composites Thermostructuraux, F-33600 Pessac (France)

    2009-03-31

    Plasma facing components (PFCs) of magnetic fusion machines have high manufactured residual stresses and have to withstand important stress ranges during operation. These actively cooled PFCs have a carbon fibre composite (CFC) armour and a copper alloy heat sink. Cracks mainly appear in the CFC near the composite/copper interface. In order to analyse damage mechanisms, it is important to well simulate the damage mechanisms both of the CFC and the CFC/Cu interface. This study focuses on the mechanical behaviour of the N11 material for which the scalar ONERA damage model was used. The damage parameters of this model were identified by similarity to a neighbour material, which was extensively analysed, according to the few characterization test results available for the N11. The finite elements calculations predict a high level of damage of the CFC at the interface zone explaining the encountered difficulties in the PFCs fabrication. These results suggest that the damage state of the CFC cells is correlated with a conductivity decrease to explain the temperature increase of the armour surface under fatigue heat load.

  11. Cooling Vest

    1983-01-01

    Because quadriplegics are unable to perspire below the level of spinal injury, they cannot tolerate heat stress. A cooling vest developed by Ames Research Center and Upjohn Company allows them to participate in outdoor activities. The vest is an adaptation of Ames technology for thermal control garments used to remove excess body heat of astronauts. The vest consists of a series of corrugated channels through which cooled water circulates. Its two outer layers are urethane coated nylon, and there is an inner layer which incorporates the corrugated channels. It can be worn as a backpack or affixed to a wheelchair. The unit includes a rechargeable battery, mini-pump, two quart reservoir and heat sink to cool the water.

  12. CASE STUDY OF ACTIVE FREE COOLING WITH THERMAL ENERGY STORAGE TECHNOLOGY

    Gravoille, Pauline

    2011-01-01

    May 25, 2011, Reuters’ headline read: "New York State is prepared for summerelectricity demand". The NY operator forecasts for next summer a peak of 33GW, close to therecord ever reached. With soaring cooling demands, the electricity peak load represents a substantialconcern to the energy system. In the goal of peak shaving, research on alternative solutions based onThermal Energy Storage (TES), for both cooling and heating applications, has been largely performed.This thesis addresses therma...

  13. Scientific feedback from high heat flux actively cooled PFCs development, realization and first results in Tore Supra

    The implementation of actively cooled high heat flux plasma facing components (PFCs) are one of the major ingredients required for operating the Tore Supra tokamak with very long pulses. A pioneering activity has been developed in this field from the very beginning of the device operation that is today culminating with the routine operation of an actively cooled toroidal pumped limiter (TPL) capable to sustain up to 10 MW.m-2 of nominal convected heat flux. A technical feedback is given from the whole development up to the industrialization and focuses on a number of critical issues, such as bonding technology analysis, manufacture processes, repair processes, destructive and non destructive testing. The actual experience in Tore Supra allows to address the question of D retention on carbon walls. Redeposition on surfaces without plasma flux is suspected to cause the final 'burial' of about the injected gas during long discharges. (authors)

  14. Modeling and simulation of an activated carbon–CO2 four bed based adsorption cooling system

    Highlights: • A transient mathematical model of a 4-bed adsorption chiller is proposed. • The performances of the cyclic-steady-state system are presented for different heating and cooling water inlet temperatures. • The desorption pressure has a big influence in the performances. • With 80 kg of Maxsorb III, the CO2 based adsorption chiller produces 2 kW of cooling power and presents a COP of 0.1. - Abstract: In this study, a transient mathematical model of a 4-bed adsorption chiller using Maxsorb III as the adsorbent and CO2 as the refrigerant has been analyzed. The performances of the cyclic-steady-state system are presented for different heating and cooling water inlet temperatures. It is found that the desorption pressure has a big influence in the performances due to the low critical point of CO2 (Tc = 31 °C). With 80 kg of Maxsorb III, the CO2 based adsorption chiller produces 2 kW of cooling power and presents a COP of 0.1, at driving heat source temperature of 95 °C along with a cooling temperature of 27 °C and at optimum desorption pressure of 79 bar. The present thermal compression air-conditioning system could be driven with solar energy or waste heat from internal combustion engines and therefore is suitable for both residential and mobile air-conditioning applications

  15. Evaluation of active cooling systems for a Mach 6 hypersonic transport airframe, part 2

    Helenbrook, R. G.; Mcconarty, W. A.; Anthony, F. M.

    1971-01-01

    Transpiration and convective cooling concepts are examined for the fuselage and tail surface of a Mach 6 hypersonic transport aircraft. Hydrogen, helium, and water are considered as coolants. Heat shields and radiation barriers are examined to reduce heat flow to the cooled structures. The weight and insulation requirements for the cryogenic fuel tanks are examined so that realistic totals can be estimated for the complete fuselage and tail. Structural temperatures are varied to allow comparison of aluminum alloy, titanium alloy, and superalloy contruction materials. The results of the study are combined with results obtained on the wing structure, obtained in a previous study, to estimate weights for the complete airframe. The concepts are compared among themselves, and with the uncooled concept on the basis of structural weight, cooling system weight, and coolant weight.

  16. Kinetic model for predicting the concentrations of active halogen species in chlorinated saline cooling waters

    Lietzke, M. H.; Haag, W. R.

    1979-01-01

    A kinetic model for predicting the composition of chlorinated water discharged from power plants using fresh water for cooling was previously reported. The model has now been extended to be applicable to power plants located on estuaries or on the seacoast where saline water is used for cooling purposes. When chloride is added to seawater to prevent biofouling in cooling systems, bromine is liberated. Since this reaction proceeds at a finite rate there is a competition between the bromine (i.e., hypobromous acid) and the added chlorine (i.e., hypochlorous acid) for halogenation of any amine species present in the water. Hence not only chloramines but also bromamines and bromochloramines will be formed, with the relative concentrations a function of the pH, temperature, and salinity of the water. The kinetic model takes into account the chemical reactions leading to the formation and disappearance of the more important halamines and hypohalous acids likely to be encountered in chlorinated saline water.

  17. Cool Temperatures Reduce Antifungal Activity of Symbiotic Bacteria of Threatened Amphibians – Implications for Disease Management and Patterns of Decline

    Daskin, Joshua H.; Bell, Sara C.; Schwarzkopf, Lin; Alford, Ross A.

    2014-01-01

    Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians’ skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd’s optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata). All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8°C to 33°C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs) from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to avoid

  18. Cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.

    Daskin, Joshua H; Bell, Sara C; Schwarzkopf, Lin; Alford, Ross A

    2014-01-01

    Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians' skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd's optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata). All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8 °C to 33 °C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs) from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to avoid

  19. Cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.

    Joshua H Daskin

    Full Text Available Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd, is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians' skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd's optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata. All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8 °C to 33 °C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to

  20. HHF test with 80x80x1 Be/Cu/SS Mock-ups for verifying the joining technology of the ITER blanket First Wall

    Through the fabrication of the Cu/SS and Be/Cu joint specimens, fabrication procedure such as material preparation, canning, degassing, HIP (Hot Isostatic Pressing), PHHT (Post HIP heat treatment) was established. The HIP conditions (1050 .deg. C, 100 MPa 2 hr for Cu/SS, 580 .deg. C 100 MPa 2 hr for Be/Cu) were developed through the investigation on joint specimen fabricated with the various HIP conditions; the destructive tests of joint include the microstructure observation of the interface with the examination of the elemental distribution, tension test, bend test, Charpy impact test and fracture toughness test. However, since the joint should be tested under the High Heat Flux (HHF) conditions like the ITER operation for verifying its joint integrity, several HHF tests were performed like the previous HHF test with the Cu/SS, Be/Cu, Be/Cu/SS Mock-ups. In the present study, the HHF test with Be/Cu/SS Mock-ups, which have 80 mm x 80 mm single Be tile and each material depths were kept to be the same as the ITER blanket FW. The Mock-ups fabricated with three kinds of interlayers such as Cr/Ti/Cu, Ti/Cr/Cu, Ti/Cu, which were different from the developed interlayer (Cr/Cu), total 6 Mock-ups were fabricated. Preliminary analysis were performed to decide the test conditions; they were tested with up to 2.5 MW/m2 of heat fluxes and 20 cycles for each Mock-up in a given heat flux. They were tested with JUDITH-1 at FZJ in Germany. During tests, all Mock-ups showed delamination or full detachment of Be tile and it can be concluded that the joints with these interlayers have a bad joining but it can be used as a good data for developing the Be/Cu joint with HIP

  1. HHF test with 80x80x1 Be/Cu/SS Mock-ups for verifying the joining technology of the ITER blanket First Wall

    Lee, Dong Won; Bae, Young Dug; Kim, Suk Kwon; Hong, Bong Guen; Jeong, Yong Hwan; Park, Jeong Yong; Choi, Byung Kwon; Jung, Hyun Kyu

    2008-11-15

    Through the fabrication of the Cu/SS and Be/Cu joint specimens, fabrication procedure such as material preparation, canning, degassing, HIP (Hot Isostatic Pressing), PHHT (Post HIP heat treatment) was established. The HIP conditions (1050 .deg. C, 100 MPa 2 hr for Cu/SS, 580 .deg. C 100 MPa 2 hr for Be/Cu) were developed through the investigation on joint specimen fabricated with the various HIP conditions; the destructive tests of joint include the microstructure observation of the interface with the examination of the elemental distribution, tension test, bend test, Charpy impact test and fracture toughness test. However, since the joint should be tested under the High Heat Flux (HHF) conditions like the ITER operation for verifying its joint integrity, several HHF tests were performed like the previous HHF test with the Cu/SS, Be/Cu, Be/Cu/SS Mock-ups. In the present study, the HHF test with Be/Cu/SS Mock-ups, which have 80 mm x 80 mm single Be tile and each material depths were kept to be the same as the ITER blanket FW. The Mock-ups fabricated with three kinds of interlayers such as Cr/Ti/Cu, Ti/Cr/Cu, Ti/Cu, which were different from the developed interlayer (Cr/Cu), total 6 Mock-ups were fabricated. Preliminary analysis were performed to decide the test conditions; they were tested with up to 2.5 MW/m2 of heat fluxes and 20 cycles for each Mock-up in a given heat flux. They were tested with JUDITH-1 at FZJ in Germany. During tests, all Mock-ups showed delamination or full detachment of Be tile and it can be concluded that the joints with these interlayers have a bad joining but it can be used as a good data for developing the Be/Cu joint with HIP.

  2. KAERI Activities on the Cooling Performance of Ex-vessel Core Catcher

    Ha, Kwang Soon; Park, Rae Joon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Wi, Kyung Jin [Chungnam National University, Daejeon (Korea, Republic of); Thanh, Thuy Nguyen Thi [University of Science and Technology, Daejeon (Korea, Republic of)

    2014-10-15

    To improve the thermal margin for the severe accident measures in high-power reactors, engineered corium cooling systems involving boiling-induced two-phase natural circulation have been proposed for decay heat removal. A boiling-induced natural circulation flow is generated in a coolant path between a hot vessel wall and cold coolant reservoir. In general, an increase in the natural circulation mass flow rate of the coolant leads to an increase in the critical heat flux (CHF) on the hot wall, thus enhancing the thermal margin. Recently, a newly engineered corium cooling system, that is, an ex-vessel core catcher, has been considered as one of severe accident mitigation measures for an APR1400. The ex-vessel core catcher in an APR1400 is a passive corium cooling system consisting of an inclined engineered cooling channel made of a single channel between the body of the core catcher and the inside wall of the reactor cavity. If a severe accident in a nuclear power plant occurs and the reactor vessel fails, the molten corium ejected from the reactor vessel is relocated in the body of the ex-vessel core catcher. The water from the IRWST is supplied to the engineered cooling channel between the outside of the core catcher body and the reactor cavity wall. The supplied water in the inclined channel should sufficiently remove the decay heat transferred from the corium by boiling off as steam. A buoyancy-driven natural circulation flow through the cooling channel and down-comers is intended to provide effective long-term cooling, and to thermally stabilize the molten corium mixture in the core catcher body.. In general, an increase in the natural circulation mass flow rate of the coolant leads to an increase in the critical heat flux (CHF) on the hot wall, thus enhancing the thermal margin. Therefore, it should be ensured and quantified that the water coolant is circulated at a sufficiently high rate through the inclined cooling channel for decay heat removal to maintain

  3. Differences Between Passive And Active Cooling Systems In Gender, Physiological Responses, Thermal Sensation And Productivity

    Schellen, Lisje; Loomans, Marcel; van Marken Lichtenbelt, Wouter; Toftum, Jørn; de Wit, Martin

    2011-01-01

    could occur due to application of low energy/exergy cooling systems, on human thermal comfort, physiological responses, and productivity. Furthermore, focus is on the differences between gender. This paper presents preliminary results obtained from experiments with four test subjects. To examine...

  4. Cooling of the auditory cortex modifies neuronal activity in the inferior colliculus in rats

    Popelář, Jiří; Šuta, Daniel; Lindovský, Jiří; Bureš, Zbyněk; Pysaněnko, Kateryna; Chumak, Tetyana; Syka, Josef

    2016-01-01

    Roč. 332, feb (2016), s. 7-16. ISSN 0378-5955 R&D Projects: GA ČR(CZ) GBP304/12/G069; GA ČR(CZ) GAP303/12/1347 Institutional support: RVO:68378041 Keywords : auditory cortex * cooling * cortical inactivation * efferent system Subject RIV: ED - Physiology Impact factor: 2.968, year: 2014

  5. Angular Momentum Loss from Cool Stars: An Empirical Expression and Connection to Stellar Activity

    Barnes, Sydney A

    2011-01-01

    We show here that the rotation period data in open clusters allow the empirical determination of an expression for the rate of loss of angular momentum from cool stars on the main sequence. One significant component of the expression, the dependence on rotation rate, persists from prior work; others do not. The expression has a bifurcation, as before, that corresponds to an observed bifurcation in the rotation periods of coeval open cluster stars. The dual dependencies of this loss rate on stellar mass are captured by two functions, $f(B-V)$ and $T(B-V)$, that can be determined from the rotation period observations. Equivalent masses and other [UBVRIJHK] colors are provided in Table 1. Dimensional considerations, and a comparison with appropriate calculated quantities suggest interpretations for $f$ and $T$, both of which appear to be related closely (but differently) to the calculated convective turnover timescale, $\\tau_c$, in cool stars. This identification enables us to write down symmetrical expressions ...

  6. Plant life management activities for long term operation of the Argentinean water cooled reactors

    , bearing replacement rates, heat exchangers tube plugging rates and corrosion rates, among others, are parameters that could be followed to evaluate the AMP effectiveness. The selection of proper indicators requires a case by case analysis and strongly depends on the particularities of each AMP AMP evaluation and feedback: Not only the selected indicators are to be evaluated, but also field experience and any other relevant data have to be collected and analyzed in order to improve the effectiveness of the AMPs. The permanent re-evaluation of the program allows for an optimization of the resources assigned to the MSI activities of each AMP. A chart summarizes the interactions between the different areas of the plant, needed for the proper establishment of a Plant Life Management for the Long Term Operation of Argentinean water cooled reactors

  7. Cool-temperature-mediated activation of phospholipase C-γ2 in the human hereditary disease PLAID.

    Schade, Anja; Walliser, Claudia; Wist, Martin; Haas, Jennifer; Vatter, Petra; Kraus, Johann M; Filingeri, Davide; Havenith, George; Kestler, Hans A; Milner, Joshua D; Gierschik, Peter

    2016-09-01

    Deletions in the gene encoding signal-transducing inositol phospholipid-specific phospholipase C-γ2 (PLCγ2) are associated with the novel human hereditary disease PLAID (PLCγ2-associated antibody deficiency and immune dysregulation). PLAID is characterized by a rather puzzling concurrence of augmented and diminished functions of the immune system, such as cold urticaria triggered by only minimal decreases in temperature, autoimmunity, and immunodeficiency. Understanding of the functional effects of the genomic alterations at the level of the affected enzyme, PLCγ2, is currently lacking. PLCγ2 is critically involved in coupling various cell surface receptors to regulation of important functions of immune cells such as mast cells, B cells, monocytes/macrophages, and neutrophils. PLCγ2 is unique by carrying three Src (SH) and one split pleckstrin homology domain (spPH) between the two catalytic subdomains (spPHn-SH2n-SH2c-SH3-spPHc). Prevailing evidence suggests that activation of PLCγ2 is primarily due to loss of SH-region-mediated autoinhibition and/or enhanced plasma membrane translocation. Here, we show that the two PLAID PLCγ2 mutants lacking portions of the SH region are strongly (>100-fold), rapidly, and reversibly activated by cooling by only a few degrees. We found that the mechanism(s) underlying PLCγ2 PLAID mutant activation by cool temperatures is distinct from a mere loss of SH-region-mediated autoinhibition and dependent on both the integrity and the pliability of the spPH domain. The results suggest a new mechanism of PLCγ activation with unique thermodynamic features and assign a novel regulatory role to its spPH domain. Involvement of this mechanism in other human disease states associated with cooling such as exertional asthma and certain acute coronary events appears an intriguing possibility. PMID:27196803

  8. Stochastic Cooling

    Blaskiewicz, M.

    2011-01-01

    Stochastic Cooling was invented by Simon van der Meer and was demonstrated at the CERN ISR and ICE (Initial Cooling Experiment). Operational systems were developed at Fermilab and CERN. A complete theory of cooling of unbunched beams was developed, and was applied at CERN and Fermilab. Several new and existing rings employ coasting beam cooling. Bunched beam cooling was demonstrated in ICE and has been observed in several rings designed for coasting beam cooling. High energy bunched beams have proven more difficult. Signal suppression was achieved in the Tevatron, though operational cooling was not pursued at Fermilab. Longitudinal cooling was achieved in the RHIC collider. More recently a vertical cooling system in RHIC cooled both transverse dimensions via betatron coupling.

  9. Is magma cooling responsible for the periodic activity of Soufrière Hills volcano, Montserrat, West Indies?

    Caricchi, Luca; Simpson, Guy; Chelle-Michou, Cyril; Neuberg, Jürgen

    2016-04-01

    After 400 years of quiescence, Soufrière Hills volcano on Montserrat (SHV) started erupting in 1995. Ongoing deformation and sulphur dioxide emission demonstrate that this volcanic systems is still restless, however, after 5 years of inactivity it remains unclear whether magma extrusion will restart. Also, if such periodically observed activity at SHV will restart, can we use past monitoring data to attempt to forecast the reawakening of this volcano? Cooling of volatile saturated magma leads to crystallisation, the formation of gas bubbles and expansion. Such volumetric variations are not only potentially responsible for deformation signals observed at the surface (Caricchi et al., 2014), but also lead to pressurisation of the magmatic reservoir and eventually renewed magma extrusion (Tait et al., 1989). We postulate that volcanic activity observed at SHM over the last 20 years could be essentially the result of the unavoidable progressive cooling of a magmatic body, which was probably assembled over thousands of years and experienced internal segregation of eruptible lenses of magma (Christopher et al., 2015). To test this hypothesis, we performed thermal modelling to test if the cooling of a shallow magma body emplaced since 1990 could account for the monitoring signals observed at SHV. The results show that progressive cooling of a 4km3 volume of melt could explain the deformation rate currently observed. Using the deformation rate obtained from the modelling for the first 15 years of cooling, a reservoir volume of about 13 km3 (Paulatto et al., 2012) and a critical value of overpressure of 10 MPa, it would have taken approximately only 3 years to pressurise the reservoir to the critical pressure and restart magma extrusion. This is in agreement with the time interval between previous pauses at SHV before 2010. Considering the current deformation rates, we speculate that magma extrusion could restart in 6-8 years after the end of the last event in 2010, hence

  10. Regional and total body active heating and cooling of a resting diver in water of varied temperatures

    Bardy, Erik [Department of Mechanical Engineering, Grove City College, 100 Campus Drive, Grove City, PA 16127 (United States); Mollendorf, Joseph [Department of Mechanical and Aerospace Engineering, State University of New York at Buffalo, 318 Jarvis Hall, Buffalo, NY 14260-4400 (United States); Pendergast, David [Department of Mechanical and Aerospace Engineering, State University of New York at Buffalo, 318 Jarvis Hall, Buffalo, NY 14260-4400 (United States)

    2008-02-07

    Passive insulations alone are not sufficient for maintaining underwater divers in thermal balance or comfort. The purpose of this study was to experimentally determine the active heating and cooling requirements to keep a diver at rest in thermal balance and comfort in water temperatures between 10 and 40 deg. C. A diver wearing a prototype tubesuit and a wetsuit (3 or 6.5 mm foam neoprene) was fully submersed (0.6 m) in water at a specified temperature (10, 20, 30 and 40 deg. C). During immersion, the tubesuit was perfused with 30 deg. C water at a flow rate of 0.5 L min{sup -1} to six individual body regions. An attempt was made to keep skin temperatures below 42 deg. C in hot water (>30 deg. C) and elevated but below 32 deg. C in cold water (<20 deg. C). A skin temperature of 32 deg. C is the threshold for maximal body thermal resistance due to vasoconstriction. Skin temperatures and core temperature were monitored during immersion to ensure they remained within set thermal limits. In addition skin heat flux, oxygen consumption and the thermal exchange of the tubesuit were measured. In both wetsuit thicknesses there was a linear correlation between the thermal exchange of the tubesuit and ambient water temperature. In the 6.5 mm wetsuit -214 W to 242 W of heating (-) and cooling (+) was necessary in 10 deg. C to 40 deg. C water, respectively. In the 3 mm wetsuit -462 to 342 W was necessary in 10 deg. C to 40 deg. C water, respectively. It was therefore concluded that a diver at rest can be kept in thermal balance in 10-40 deg. C water with active heating and cooling.

  11. Modular jet impingement assemblies with passive and active flow control for electronics cooling

    Zhou, Feng; Dede, Ercan Mehmet; Joshi, Shailesh

    2016-09-13

    Power electronics modules having modular jet impingement assembly utilized to cool heat generating devices are disclosed. The modular jet impingement assemblies include a modular manifold having a distribution recess, one or more angled inlet connection tubes positioned at an inlet end of the modular manifold that fluidly couple the inlet tube to the distribution recess and one or more outlet connection tubes positioned at an outlet end of the modular manifold that fluidly coupling the outlet tube to the distribution recess. The modular jet impingement assemblies include a manifold insert removably positioned within the distribution recess and include one or more inlet branch channels each including an impinging slot and one or more outlet branch channels each including a collecting slot. Further a heat transfer plate coupled to the modular manifold, the heat transfer plate comprising an impingement surface including an array of fins that extend toward the manifold insert.

  12. A full-scale experimental set-up for assessing the energy performance of radiant wall and active chilled beam for cooling buildings

    Le Dreau, Jerome; Heiselberg, Per; Jensen, Rasmus Lund

    2015-01-01

    in decreasing the cooling need of the radiant wall compared to the active chilled beam. It has also been observed that the type and repartition of heat load have an influence on the cooling demand. Regarding the comfort level, both terminals met the general requirements, except at high solar heat...... gains: overheating has been observed due to the absence of solar shading and the limited cooling capacity of the terminals. No local discomfort has been observed although some segments of the thermal manikin were slightly colder....

  13. Effect of soaking, boiling, and steaming on total phenolic contentand antioxidant activities of cool season food legumes.

    Xu, Baojun; Chang, Sam K C

    2008-09-01

    The effects of soaking, boiling and steaming processes on the total phenolic components and antioxidant activity in commonly consumed cool season food legumes (CSFL's), including green pea, yellow pea, chickpea and lentil were investigated. As compared to original unprocessed legumes, all processing steps caused significant (pyellow pea. However, TPC and DPPH in cooked lentils differed significantly between atmospheric and pressure boiling. As compared to atmospheric processes, pressure processes significantly increased ORAC values in both boiled and steamed CSFL's. Greater TPC, DPPH and ORAC values were detected in boiling water than that in soaking and steaming water. Boiling also caused more solid loss than steaming. Steam processing exhibited several advantages in retaining the integrity of the legume appearance and texture of the cooked product, shortening process time, and greater retention of antioxidant components and activities. PMID:26050159

  14. Solar absorption cooling

    Kim, D.-S.

    2007-01-01

    As the world concerns more and more on global climate changes and depleting energy resources, solar cooling technology receives increasing interests from the public as an environment-friendly and sustainable alternative. However, making a competitive solar cooling machine for the market still remains a challenge to the academic and industrial communities. In an effort to meet this challenge, this thesis reports the R&D activities carried out for the development of a new solar cooling machine,...

  15. Activation product transport in the helium cooling circuit of the SEAFP Plant Model 1

    This paper presents results using the steady-state activation transport and deposition code TRAP. Activation of the helium coolant and pipe wall deposits are calculated at important locations of the primary circuit loop of the SEAFP Plant Model 1. The dominant sources of active material in the coolant comprise a nuclear sputtering mechanism and direct generation in the coolant due to the neutron-coolant interaction. Coolant activity behavior is shown to be dictated by the volatile nuclides whereas surface activity behavior is dictated by the non-volatiles. Resulting hazards are estimated to be extremely small

  16. Interface structure in carbon and graphite fiber reinforced 2014 aluminum alloy processed with active fiber cooling

    The fiber/matrix interfaces developed in continuous carbon fiber (CF) and graphite fiber (GRF) reinforced 2014 aluminum matrix composites were characterized using scanning and transmission electron microscopy (TEM). The as-cast CF/2014 Al and GRF/2014 Al composite specimens were processed by pressure infiltration of continuous fiber bundles preheated at 500 deg. C, while the fiber reinforcements were externally cooled during infiltration by exposing fiber ends to atmospheric air. Very limited precipitation of secondary phases along the fiber matrix interface was observed in the microstructure. Most of the secondary phases identified in the matrix in the interfiber regions included Al20Cu2Mn3, AlSiMnFe or Al2Cu within interfiber regions. Other interfacial reaction products detected were Cu- and Si-based spinels in the CF composite and an amorphous Al-C-O layer in the GRF composite. In both composites, Al4C3 was detected but its frequency of occurrence was rather low, particularly in the GRF composite interfaces. The formation of relatively clean GRF/matrix interfaces in the GRF composite suggests nucleation of primary alpha-aluminum phase on some parts of graphite fiber surface; the orientation relationship between GRF and aluminum appears to be (0 2 0)Al//(0 0 0 2)GRF in the present study

  17. Improving activity transport models for water-cooled nuclear power reactors

    Eight current models for describing radioactivity transport and radiation field growth around water-cooled nuclear power reactors have been reviewed and assessed. A frequent failing of the models is the arbitrary nature of the determination of the important processes. Nearly all modelers agree that the kinetics of deposition and release of both dissolved and particulate material must be described. Plant data must be used to guide the selection and development of suitable improved models, with a minimum of empirically-based rate constraints being used. Limiting case modelling based on experimental data is suggested as a way to simplify current models and remove their subjectivity. Improved models must consider the recent change to 'coordinated water chemistry' that appears to produce normal solubility behaviour for dissolved iron throughout the fuel cycle in PWRs, but retrograde solubility remains for dissolved nickel. Profiles are suggested for dissolved iron and nickel concentrations around the heat transport system in CANDU reactors, which operate nominally at constant chemistry, i.e., pHT constant with time, and which use carbon steel isothermal piping. These diagrams are modified for a CANDU reactor with stainless steel piping, in order to show the changes expected. The significance of these profiles for transport in PWRs is discussed for further model improvement. (author)

  18. Recent advances in actively cooled high-power laser diode bars

    Ostrom, Nels P.; Roh, S. D.; Grasso, Daniel M.; Kane, Thomas J.

    2007-02-01

    In order to meet the ever increasing demands of many high power laser diode customers, Nuvonyx has worked to improve a number of key metrics of the diode laser package. The most often challenged specifications are power per bar, efficiency, and reliability in both hard pulse and constant current mode. In response to these requests, Nuvonyx has worked to offer commercial component devices in excess of 100 and 150 watts per bar package in multiple wavelengths. The packages are routinely combined to form single stacks that generate greater than 3.5 kilowatts each and two-dimensional arrays which produce light in excess of 10 kilowatts. These parts all demonstrate predicted lifetimes in excess of 10,000 hours. The micro-channel cooled heat sink has also been improved by closer matching the coefficient of thermal expansion of the cooler to the laser diode bar, which allows for harder solders such as gold-tin to be employed. All of this work has helped to meet the specifications of the most demanding laser diode customers.

  19. Initial measurements with an actively cooled calorimeter in a large pool fire

    Koski, J.A.; Kent, L.A. [Sandia National Labs., Albuquerque, NM (United States); Wix, S.D. [Gram, Inc., Albuquerque, NM (United States)

    1993-11-01

    The initial measurements with a 1 m {times} 1 m water cooled vertical flat plate calorimeter located 0.8 m above and inside a 6 m {times} 6 m JP-4 pool fire are described. Heat fluxes in ten vertical 0. 1 m high {times} 1 m wide zones were measured by means of water calorimetry in quasi-steady-state. The calorimeter face also included an array of intrinsic thermocouples to measure surface temperatures, and an array of Schmidt-Boelter radiometers for a second, more responsive, method of heat flux measurement. Other experimental measurement devices within the pool fire included velocity probes, directional flame thermometers (DFTs), and thermocouples. Water calorimetry indicated heat fluxes of about 65 to 70 kW/m{sup 2} with a gradual decrease with increasing height above the pool. Intrinsic thermocouple measurements recorded typical calorimeter surface temperatures of about 500{degrees}C, with spatial variations of {plus_minus}150{degrees}C. Gas velocities across the calorimeter face averaged 3.4 m/s with a predominant upward component, but with an off-vertical skew. Temperatures of 800 to 1100{degrees}C were measured with the DFTS. The observed decrease in heat flux with increasing vertical height is consistent with analytical fire models derived for constant temperature surfaces. Results from several diagnostics also indicated trends and provided additional insight into events that occurred during the fire. Some events are correlated, and possible explanations are discussed.

  20. High energy electron cooling

    Parkhomchuk, V. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-09-01

    High energy electron cooling requires a very cold electron beam. The questions of using electron cooling with and without a magnetic field are presented for discussion at this workshop. The electron cooling method was suggested by G. Budker in the middle sixties. The original idea of the electron cooling was published in 1966. The design activities for the NAP-M project was started in November 1971 and the first run using a proton beam occurred in September 1973. The first experiment with both electron and proton beams was started in May 1974. In this experiment good result was achieved very close to theoretical prediction for a usual two component plasma heat exchange.

  1. Ion Beam Analysis methods applied to the examination of Be//Cu joints in hipped Be tiles for ITER first wall mock- ups

    A proposed fabrication route for ITER first wall components implies a diffusion welding step of Be tiles onto a Cu-based substrate. However, Be has a tendency to form particularly brittle intermetallics with Cu and a lot of other elements. Insertion of interlayers may be a solution to increase bond quality. Applying traditional analyses to this study can be problematic because of Be toxicity and low atomic number Z. Ion Beam Analysis methods have thus been considered together with scanning electron microscopy (SEM) and electron back-scattering diffraction (EBSD) as complementary techniques. The following work aims at demonstrating how such techniques (used in micro-beam mode), and in particular NRA (Nuclear Reaction Analysis) and PIXE (Particle Induced X-ray Emission) techniques, coupled with SEM/EBSD data, can bring valuable information in this area. Quantification of data allow to obtain concentration values (provided the hypotheses on the initial junction composition are valuable), then phase diagrams give clues about the composition and structure of the junction. SEM retro-diffused electrons chemical contrast images and EBSD allow to characterize the presence of the awaited intermetallics, and finally confirm or refine the conclusions of Ion Beam Analysis data quantification. A series of reference first wall mock-ups have been analysed. Interlayer-free mock-ups reveal intermetallics which are mainly BeCu (apparently mixed with lower quantities of BeCu2 compound). While Cr or Ti interlayers seem to behave as good Be diffusion barriers in the sense that they prevent the formation of BeCu, they strongly interact with Cu to form CuTi2 or Cr2Ti intermetallics. In the case of Cr, Be seems to be incorporated into the Cr layer. PIXE analysis has however been unable to characterize Al-based interlayers (Z=13, close to the lower PIXE sensibility limit) and emphasizes one limitation of Ion Beam Analysis methods for lighter metals, justifying the use of other complementary

  2. Velocity dependence of ionization probability of Be, Cu, Ag, W, Pb and Sn atoms sputtered by 5.5 keV Ar+ ions

    The energy distributions of both ions and neutral atoms sputtered during ion bombardment of a few polycrystalline metals have been measured. The absolute values of the ionization probability P+ as a function of the emitted particle velocity ν were obtained. The ionization probability for Be, Cu, Ag and W targets is found to depend exponentially on the particle velocity in accordance with the electron tunneling model. In the case of Pb and Sn the ionization probability shows strong deviation from an exponential dependence at high emission energies. (author)

  3. A fuselage/tank structure study for actively cooled hypersonic cruise vehicles, summary. [aircraft design of aircraft fuel systems

    Pirrello, C. J.; Baker, A. H.; Stone, J. E.

    1976-01-01

    A detailed analytical study was made to investigate the effects of fuselage cross section (circular and elliptical) and the structural arrangement (integral and nonintegral tanks) on aircraft performance. The vehicle was a 200 passenger, liquid hydrogen fueled Mach 6 transport designed to meet a range goal of 9.26 Mn (5000 NM). A variety of trade studies were conducted in the area of configuration arrangement, structural design, and active cooling design in order to maximize the performance of each of three point design aircraft: (1) circular wing-body with nonintegral tanks, (2) circular wing-body with integral tanks and (3) elliptical blended wing-body with integral tanks. Aircraft range and weight were used as the basis for comparison. The resulting design and performance characteristics show that the blended body integral tank aircraft weights the least and has the greatest range capability, however, producibility and maintainability factors favor nonintegral tank concepts.

  4. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... the performance of the new deck with PCM concrete is the thermal properties of such a new material, as the PCM concrete is yet to be well defined. The results presented in the paper include models in which the PCM concrete material properties, such as thermal conductivity, and specific heat capacity were first...... with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating...

  5. Plant Life Management Activities for Long Term Operation of the Argentinean Water Cooled Reactors

    The Comision Nacional de Energia Atomica (CNEA) -National Atomic Energy Agency of Argentina- is a Sate-owned Research and Development (R and D) institution that has among its functions the responsibility of keeping up to date, and available to the Utilities, all nuclear related technologies in order to ensure the highest performance of the plants in terms of safety and production. Within the last years CNEA has developed a working group focused in the aspect related with Plant Life Management for Long Term Operation. In this work a brief review of the activities that are being carried out in this group are presented, which include development of methodologies and procedures for Ageing Managements Program, R and D activities in Ageing Related Degradation Mechanisms, and technical assistance activities for the Argentinean NPPs. (author)

  6. Specimen alignment in an axial tensile test of thin films using direct imaging and its influence on the mechanical properties of BeCu

    This paper proposes a new system for verification of the alignment of loading fixtures and test specimens during tensile testing of thin film with a micrometer size through direct imaging. The novel and reliable image recognition system to evaluate the misalignment between the load train and the specimen axes during tensile test of thin film was developed using digital image processing technology with CCD. The decision of whether alignment of the tensile specimen is acceptable or not is based on a probabilistic analysis through the edge feature extraction of digital imaging. In order to verify the performance of the proposed system and investigate the effect of the misalignment of the specimen on tensile properties, the tensile tests were performed as displacement control in air and at room temperature for metal thin film, the beryllium copper (BeCu) alloys. In the case of the metal thin films, bending stresses caused by misalignment are insignificant because the films are easily bent during tensile tests to eliminate the bending stresses. And it was observed that little effects and scatters on tensile properties occur by stress gradient caused by twisting at in-plane misalignment, and the effects and scatters on tensile properties are insignificant at out-of-plane misalignment, in the case of the BeCu thin film.

  7. Cooled Transmission-Mode NEA-Photocathode with a Band-Graded Active Layer for High Brightness Electron Source

    Jones, L. B.; Rozhkov, S. A.; Bakin, V. V.; Kosolobov, S. N.; Militsyn, B. L.; Scheibler, H. E.; Smith, S. L.; Terekhov, A. S.

    2009-08-01

    A Free-Electron Laser (FEL) places many exacting demands on a Negative Electron Affinity (NEA) photocathode, such as the need for an ultra-fast response time, low energy spread for emitted electrons, high quantum efficiency (Q.E.) and a high average photocurrent. However, these key requirements are conflicting, and cannot be fulfilled by conventional photocathode design. For example, to achieve ˜10 ps response time, the photocathode active layer should be thinned to ˜100-150 nm, but this thickness is insufficient to provide near-complete absorption of light with hv≈ɛg so high Q.E. cannot be achieved. Complete optical absorption and high Q.E. can be obtained using a thin active layer at higher photon energies, but this generates photoelectrons with excess kinetic energy within the semiconductor. These photoelectrons do not thermalise in a thin active layer, so yield a broad energy distribution in the emitted electrons. Moreover, cooling of the conventional semiconductor photocathode structure is ineffective due to its fragility, so it cannot be pressed firmly to a heat sink to attain good thermal contact. Consequently, the maximum CW photocurrent is limited to a few miiliamps. The goal of our work is to develop a new design of NEA-photocathode which is optimised for FEL applications.

  8. Spray cooling

    Spray cooling - using water spraying in air - is surveyed as a possible system for make-up (peak clipping in open circuit) or major cooling (in closed circuit) of the cooling water of the condensers in thermal power plants. Indications are given on the experiments made in France and the systems recently developed in USA, questions relating to performance, cost and environmental effects of spray devices are then dealt with

  9. Review of activities of Research Association of High Temperature Gas Cooled Reactor Plant (RAHP)

    The Research Association of the HTGR Plant (RAHP) is the sole research association in the private or industrial sector of Japan with respect to HTGR Plants. It was established in 1985, composing of professors, representatives of electric power companies, and fabricators of nuclear plant and fuels Activities in these years were to analyze world trends of R and D, to identify techno-economical issues to be cleared, to set-up fundamental development strategies, and to put the results of the studies into actions towards commercialization of the HTGR. Conclusions obtained through the activities so far are: (1) From the view point of effective use of energy and reduction of environmental impacts on a global scale, development of nuclear power is essential, in particular of the HTGR, because of its very highly inherent safety and feasibility of high temperature heat uses. The role of the HTGR is inter-complementary with those of LWR and FBR; (2) Future subjects on the HTGR are technical demonstration of its unique characteristics, economic prospects, public acceptance (PA) and industrial acceptance, R and D through international cooperation and share in role, and successful realization of demonstration plant(s). RAHP is to start a survey on HTGR from nuclear fuel cycle point of view to have a better outlook on future needs of high temperature heat uses. 6 refs

  10. HHF Test with 35x35x3 Be/Cu Mockups for Verifying the HIP Joining Technology of the ITER Blanket First Wall

    Since the high heat flux (HHF) test is essential for verifying the joint integrity of the ITER blanket first wall with the similar heat flux like the ITER operation conditions, several HHF tests were performed like the previous tests with the Cu/SS, Be/Cu, Be/Cu/SS mockups. In the present study, the HHF tests with Be/Cu mockups were introduced, which have three 35 mm x 35 mm Be tiles and each material depths were kept to be the same as the ITER blanket. Six mockups were fabricated with three kinds of interlayers such as 10μmCr/10μmCu, 1μmCr/10μmCu, 1μmTi/0.5μmCr/10μmCu, 5μmTi/10μmCu. Ten mockups were fabricated with the above conditions but one mockup (10μmCr/10μmCu interlayer) was failed during fabrication process. So, the first four mockups were excluded in the HHF test. Other six mockups were used in the present HHF test. According to the test conditions determined by the preliminary analysis with ANSYS code in the case of 1.5 and 1.0 MW/m2 heat fluxes, the tests were performed. The coolant conditions of the test facility, KoHLT-1 were considered in the simulation and used in the HHF test. Before the HHF test, shear test and non-destructive test with ultrasonic probe were performed with the fabricated mockups. One mockup showed a Be tile delamination during the screening test but the other survived up to 862 cycles under 1.0 MW/m2 heat flux. Other four mockups survived up to 1,100 cycles under the same heat flux without any delamination or Be tile damage, therefore, it shows that the joint integrity has no problem even with the loaded certain heat. And more, three interlayers show the their applicability as a Be to Cu joining one but it needs more attention at the interlayer coating for the reproducibility

  11. R and D activities on helium cooled solid breeder TBM in Korea

    R and D activities currently being undertaken for HCSB TBM include joining technologies of structural material, breeder and reflector pebble material development, the effect of TBM ferritic-martensitic steel on the ripple of toroidal magnetic field, and ceramic coating on graphite pebble. The HIP joining performance of FM steel is evaluated. Lithium ceramic breeder and graphite reflector pebble fabrication methods are under development using special fabrication process, and the initial characteristics of the pebbles are assessed. Silicon carbide coating on graphite pebble is also investigated and its preliminary results are mentioned. Finally, an accurate evaluation of the effect of TBM and ferromagnetic inserts on magnetic field are implemented. The current results of these R and D issues are addressed in this paper.

  12. Cathepsin activities and membrane integrity of zebrafish (Danio rerio) oocytes after freezing to -196 degrees C using controlled slow cooling.

    Zhang, T; Rawson, D M; Tosti, L; Carnevali, O

    2008-04-01

    This study investigated enzymatic activity of cathepsins and the membrane integrity of zebrafish (Danio rerio) oocytes after freezing to -196 degrees C using controlled slow cooling. Stage III oocytes (>0.5mm), obtained through dissection of anaesthetised female fish and desegregation of ovarian cumulus, were exposed to 2M methanol or 2M DMSO (both prepared in Hank's medium) for 30min at 22 degrees C before being loaded into 0.5ml plastic straws and placed into a programmable cooler. After controlled slow freezing, samples were plunged into liquid nitrogen (LN) and held for at least 10min, and thawed by immersing straws into a 27 degrees C water bath for 10s. Thawed oocytes were washed twice in Hank's medium. Cathepsin activity and membrane integrity of oocytes were assessed both after cryoprotectant treatment at 22 degrees C and after freezing in LN. Cathepsin B and L colorimetric analyses were performed using substrates Z-Arg-ArgNNap and Z-Phe-Arg-4MbetaNA-HCl, respectively, and 2-naphthylamine and 4-methoxy-2-naphthylamine were used as standards. Cathepsin D activity was performed by analysing the level of hydrolytic action on haemoglobin. Oocytes membrane integrity was assessed using 0.2% Trypan blue staining for 5min. Analysis of cathepsin activities showed that whilst the activity of cathepsin B and D was not affected by 2M DMSO treatment, their activity was lowered when treated with 2M methanol. Following freezing to -196 degrees C, the activity of all cathepsins (B, D and L) was significantly decreased in both 2M DMSO and 2M methanol. Trypan blue staining showed that 63.0+/-11.3% and 72.7+/-5.2% oocytes membrane stayed intact after DMSO and methanol treatment for 30min at 22 degrees C, respectively, whilst 14.9+/-2.6% and 1.4+/-0.8% stayed intact after freezing in DMSO and methanol to -196 degrees C. The results indicate that cryoprotectant treatment and freezing modified the activities of lysosomal enzymes involved in oocyte maturation and yolk

  13. Cool C4 Photosynthesis - Pyruvate Pi dikinase expression and activity corresponds to the exceptional cold tolerance of carbon assimilation in Miscanthus x giganteus

    The biofuel feedstock grass Miscanthus x giganteus is exceptional among C4 species in its high productivity in cold climates. It can maintain photosynthetically active leaves at temperatures 6°C below the minimum for Zea mays (maize), which allows it a longer growing season in cool climates. Underst...

  14. Cool contrails

    U. Schumann

    2012-01-01

    Contrails are cirrus clouds which warm or cool the Earth depending on flight route and weather. Hence, the climate impact of aviation can be minimised by avoiding warming contrails and allowing for cooling contrails by proper weather dependent route selection. This article summarises recent research results on this topic.

  15. High-flux deuterium plasma exposure tests of actively-cooled divertor plate units in PISCES-B

    An actively-cooled divertor plate mock-up with three kinds of carbon-based armor tiles (IG430U, MFC-1, and CX2002U) designed and fabricated by JAERI was bombarded with steady-state and high-flux deuterium plasmas produced in UCLA PISCES-B. The plasma densities, electron temperatures, and ion fluxes were measured from 1 to 3x1019 m-3, from 4 to 12 eV, and from 1.2 to 2.1x1023 ions/m2s, respectively. The total ion fluence was of the order of 1026 ions/m2. Interesting surface morphologies have been observed for the plasma-bombarded surfaces, having relatively large agglomerated carbon particles with diameters up to 100 micrometer. The plasma heat flux was measured with a calorimeter embedded in a graphite (IG430U) to range from 1.1 to 4.4 MW/m2, which is in good agreement with the calculated value with a simple sheath theory. (author)

  16. Steady-state heat and particle removal with the actively cooled Phase III Outboard Pump Limiter in Tore Supra

    Tore Supra's Phase III Outboard Pump Limiter (OPL) is a modular actively-cooled midplane limiter, designed for heat and particle removal during long pulse operation. During its initial operation in 1993, the OPL successfully removed about 1 MW of power during ohmically heated shots of up to 10 seconds duration and reached (steady state) thermal equilibrium. The particle pumping of the Phase III OPL was found to be about 50% greater than the Phase II OPL which had a radial distance between the last closed flux surface and the entrance of the pumping throat of 3.5 cm compared with only 2.5 cm for the Phase III OPL. This paper gives examples of power distribution over the limiter from IR measurements of surface temperature and from extensive calorimetry (34 thermocouples and 10 flow meters) and compares the distributions with values predicted by a 3-D model (HF3D) with a detailed magnetic configuration (e.g., includes field ripple)

  17. Infrared surface temperature measurements for long pulse operation, and real time feedback control in Tore-Supra, an actively cooled Tokamak

    Guilhem, D.; Adjeroud, B.; Balorin, C.; Buravand, Y.; Bertrand, B.; Bondil, J.L.; Desgranges, C.; Gauthier, E.; Lipa, M.; Messina, P.; Missirlian, M.; Mitteau, R.; Moulin, D.; Pocheau, C.; Portafaix, C.; Reichle, R.; Roche, H.; Saille, A.; Vallet, S

    2004-07-01

    Tore-Supra has a steady-state magnetic field using super-conducting magnets and water-cooled plasma facing components for high performances long pulse plasma discharges. When not actively cooled, plasma-facing components can only accumulate a limited amount of energy since the temperature increase continuously (T proportional to {radical}(t)) during the discharge until radiation cooling is equal to the incoming heat flux (T > 1800 K). Such an environment is found in most today Tokamaks. In the present paper we report the recent results of Tore-Supra, especially the design of the new generation of infrared endoscopes to measure the surface temperature of the plasma facing components. The Tore-Supra infrared thermography system is composed of 7 infrared endoscopes, this system is described in details in the paper, the new JET infrared thermography system is presented and some insights of the ITER set of visible/infrared endoscope is given. (authors)

  18. Infrared surface temperature measurements for long pulse operation, and real time feedback control in Tore-Supra, an actively cooled Tokamak

    Tore-Supra has a steady-state magnetic field using super-conducting magnets and water-cooled plasma facing components for high performances long pulse plasma discharges. When not actively cooled, plasma-facing components can only accumulate a limited amount of energy since the temperature increase continuously (T proportional to √(t)) during the discharge until radiation cooling is equal to the incoming heat flux (T > 1800 K). Such an environment is found in most today Tokamaks. In the present paper we report the recent results of Tore-Supra, especially the design of the new generation of infrared endoscopes to measure the surface temperature of the plasma facing components. The Tore-Supra infrared thermography system is composed of 7 infrared endoscopes, this system is described in details in the paper, the new JET infrared thermography system is presented and some insights of the ITER set of visible/infrared endoscope is given. (authors)

  19. Active chemistry control for coolant helium applying high-temperature gas-cooled reactors - HTR2008-58096

    Lifetime extension of high-temperature equipment such as the intermediate heat exchanger of high-temperature gas-cooled reactors (HTGRs) is important from the economical point of view. Since the replacing cost will cause the increasing of the running cost, it is important to reduce replacing times of the high-cost primary equipment during assumed reactor lifetime. In the past, helium chemistry has been controlled by the passive chemistry control technology in which chemical impurity in the coolant helium is removed as low concentration as possible, as does Japan's HTTR. Although the lifetime of high- temperature equipment almost depends upon the chemistry conditions in the coolant helium, it is necessary to establish an active chemistry control technology to maintain adequate chemical conditions. In this study, carbon deposition which could occur at the surface of the heat transfer tubes of the intermediate heat exchanger and decarburization of the high-temperature material of Hastelloy XR used at the heat transfer tubes were evaluated by referring the actual chemistry data obtained by the HTTR. The chemical equilibrium study contributed to clarify the algorism of the chemistry behaviours to be controlled. The created algorism is planned to be added to the instrumentation system of the helium purification systems. In addition, the chemical composition to be maintained during the reactor operation was proposed by evaluating not only core graphite oxidation but also carbon deposition and decarburization. It was identified when the chemical composition could not keep adequately, injection of 10 ppm carbon monoxide could effectively control the chemical composition to the designated stable area where the high-temperature materials could keep their structural integrity beyond the assumed duration. The proposed active chemistry control technology is expected to contribute economically to the purification systems of the future very high-temperature reactors. (authors)

  20. Electron Beam Welding of Reduced Activation Ferritic Martensitic ODS-EUROFER Steel for Application in Helium Cooled Modular Divertor Concepts

    For specific blanket and divertor applications in future fusion power reactors a replacement of presently considered Reduced Activation Ferritic Martensitic (RAFM) steels as structural material by suitable oxide dispersion strengthened (ODS) ferritic martensitic or ferritic steels would allow a substantial increase of the operating temperature from ∼ 550 oC to about 650 oC. In all cases appropriate joining technologies have to be developed. Diffusion welding techniques to perform similar and dissimilar joints have been studied successfully. Friction Stir Welding (FSW) has shown a good potential but application is limited due to geometrical restrictions and needs further development. For the advanced helium-cooled modular divertor concept various joining techniques are required for joining the complex structural parts made of different materials. First attempts have been made for joining the divertor structures of ODS EUROFER by means of the Electron beam welding process with its highly concentrated energy input. This welding is widely used to produce high quality-high integrity welded similar and dissimilar joints of a large variety of materials. For this purpose, samples of ODS-EUROFER steel were welded using a PTR 150 kV/15 kW EB welding facility. Two different post-weld heat treatments (PWHT) were applied to investigate their influence on the mechanical and microstructural properties of the welded joints. Miniaturised tensile specimens were used to determine the tensile behaviour in the temperature range between RT and 700 oC. KLST specimens were used for Charpy impact tests. The microstructure of the weld and heat affected zone was examined using optical and scanning electron microscopy. Transmission electron microscopical methods were applied to investigate the size and spatial distribution of the dispersed oxides and potential segregation phenomena. (author)

  1. The use of copper alloy CuCrZr as a structural material for actively cooled plasma facing and in vessel components

    Lipa, M.; Durocher, A. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Tivey, R. [ITER, Garching Joint Work Site, Garching (Germany); Huber, Th.; Schedler, B. [Plansee AG, Reutte (Austria); Weigert, J. [PTR Praezisionstechnik GmbH, Maintal-Doernigheim (Germany)

    2004-07-01

    This paper presents our experience with precipitation hardened CuCrZr in the fabrication of actively cooled components for Tore Supra (toroidal pump limiter fingers, guard limiter heat sink hollow-profiles, ripple protection tubes, endoscope heads) and JET high heat flux elements for the beam-lines. The supposed interplay phenomenon between CuCrZr procurement, component geometry and welding procedure is discussed. The associated mechanical characterisation of materials from different suppliers and component joining, focused especially on CuCrZr-CuCrZr fusion weldings using electron beams, is presented. The behaviour of an actively cooled CuCrZr component during accidental operation conditions in Tore Supra is described. (authors)

  2. Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report

    A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking

  3. Kinetic model for predicting the concentrations of active halogens species in chlorinated saline cooling waters. Final report

    Haag, W.R.; Lietzke, M.H.

    1981-08-01

    A kinetic model has been developed for describing the speciation of chlorine-produced oxidants in seawater as a function of time. The model is applicable under a broad variety of conditions, including all pH range, salinities, temperatures, ammonia concentrations, organic amine concentrations, and chlorine doses likely to be encountered during power plant cooling water chlorination. However, the effects of sunlight are not considered. The model can also be applied to freshwater and recirculating water systems with cooling towers. The results of the model agree with expectation, however, complete verification is not feasible at the present because analytical methods for some of the predicted species are lacking.

  4. CO2 laser beam test of an actively cooled first-wall element with a graphite-clad SiC armor tile

    A graphite-clad SiC tile of 29mm dia and 15mm thickness is bonded to a base metal (Cu or 316 SS) with insertion of Cu-35 vol%C composite sheet. The elements are tested under active cooling condition by using 3.5kW CO2 laser beam at heat flux condition of 0.3 ∼ 1.7kW/cm2 and a pulse length of 40s

  5. Neutron Damage in Mechanically-Cooled High-Purity Germanium Detectors for Field-Portable Prompt Gamma Neutron Activation Analysis (PGNAA) Systems

    E.H. Seabury; C.J. Wharton; A.J. Caffrey; J.B. McCabe; C. DeW. Van Siclen

    2013-10-01

    Prompt Gamma Neutron Activation (PGNAA) systems require the use of a gamma-ray spectrometer to record the gamma-ray spectrum of an object under test and allow the determination of the object’s composition. Field-portable systems, such as Idaho National Laboratory’s PINS system, have used standard liquid-nitrogen-cooled high-purity germanium (HPGe) detectors to perform this function. These detectors have performed very well in the past, but the requirement of liquid-nitrogen cooling limits their use to areas where liquid nitrogen is readily available or produced on-site. Also, having a relatively large volume of liquid nitrogen close to the detector can impact some assessments, possibly leading to a false detection of explosives or other nitrogen-containing chemical. Use of a mechanically-cooled HPGe detector is therefore very attractive for PGNAA applications where nitrogen detection is critical or where liquid-nitrogen logistics are problematic. Mechanically-cooled HPGe detectors constructed from p-type germanium, such as Ortec’s trans-SPEC, have been commercially available for several years. In order to assess whether these detectors would be suitable for use in a fielded PGNAA system, Idaho National Laboratory (INL) has been performing a number of tests of the resistance of mechanically-cooled HPGe detectors to neutron damage. These detectors have been standard commercially-available p-type HPGe detectors as well as prototype n-type HPGe detectors. These tests compare the performance of these different detector types as a function of crystal temperature and incident neutron fluence on the crystal.

  6. Cool snacks

    Grunert, Klaus G; Brock, Steen; Brunsø, Karen;

    2016-01-01

    product requires an interdisciplinary effort where researchers with backgrounds in psychology, anthropology, media science, philosophy, sensory science and food science join forces. We present the COOL SNACKS project, where such a blend of competences was used first to obtain thorough insight into young...

  7. Cooling towers

    This paper investigates the internal elements of the typical types of cooling towers currently used, delineates their functions and shows how to upgrade them in the real world for energy savings and profitability of operation. Before and after statistics of costs and profits obtained through optimization of colder water by engineered thermal upgrading are discussed

  8. Stochastic cooling

    Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron

  9. Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors. Publishable Final Activity Report

    The PUMA project -the acronym stands for 'Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors'- was a Specific Targeted Research Project (STREP) within the EURATOM 6th Framework Program (EU FP6). The PUMA project ran from September 1, 2006, until August 31, 2009, and was executed by a consortium of 14 European partner organisations and one from the USA. This report serves 2 purposes. It is both the 'Publishable Final Activity Report' and the 'Final (Summary) Report', describing, per Work Package, the specific objectives, research activities, main conclusions, recommendations and supporting documents. PUMA's main objective was to investigate the possibilities for the utilisation and transmutation of plutonium and especially minor actinides in contemporary and future (high temperature) gas-cooled reactor designs, which are promising tools for improving the sustainability of the nuclear fuel cycle. This contributes to the reduction of Pu and MA stockpiles, and also to the development of safe and sustainable reactors for CO2-free energy generation. The PUMA project has assessed the impact of the introduction of Pu/MA-burning HTRs at three levels: fuel and fuel performance (modelling), reactor (transmutation performance and safety) and reactor/fuel cycle facility park. Earlier projects already indicated favourable characteristics of HTRs with respect to Pu burning. So, core physics of Pu/MA fuel cycles for HTRs has been investigated to study the CP fuel and reactor characteristics and to assure nuclear stability of a Pu/MA HTR core, under both normal and abnormal operating conditions. The starting point of this investigation comprised the two main contemporary HTR designs, viz. the pebble-bed type HTR, represented by the South-African PBMR, and hexagonal block type HTR, represented by the GT-MHR. The results (once again) demonstrate the flexibility of the contemporary (and near future) HTR designs and their ability to accept a variety

  10. Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors. Publishable Final Activity Report

    The PUMA project - the acronym stands for “Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors” - was a Specific Targeted Research Project (STREP) within the Euratom 6th Framework (EU FP6). The PUMA project ran from September 1, 2006, until August 31, 2009, and was executed by a consortium of 14 European partner organisations and one from the USA. This report serves 2 purposes. It is both the 'Publishable Final Activity Report' and the 'Final (Summary) Report', describing, per Work Package, the specific objectives, research activities, main conclusions, recommendations and supporting documents. PUMA's main objective was to investigate the possibilities for the utilisation and transmutation of plutonium and especially minor actinides in contemporary and future (high temperature) gas-cooled reactor designs, which are promising tools for improving the sustainability of the nuclear fuel cycle. This contributes to the reduction of Pu and MA stockpiles, and also to the development of safe and sustainable reactors for CO2-free energy generation. The PUMA project has assessed the impact of the introduction of Pu/MA-burning HTRs at three levels: fuel and fuel performance (modelling), reactor (transmutation performance and safety) and reactor/fuel cycle facility park. Earlier projects already indicated favourable characteristics of HTRs with respect to Pu burning. So, core physics of Pu/MA fuel cycles for HTRs has been investigated to study the CP fuel and reactor characteristics and to assure nuclear stability of a Pu/MA HTR core, under both normal and abnormal operating conditions. The starting point of this investigation comprised the two main contemporary HTR designs, viz. the pebble-bed type HTR, represented by the South-African PBMR, and hexagonal block type HTR, represented by the GT-MHR. The results (once again) demonstrate the flexibility of the contemporary (and near future) HTR designs and their ability to accept a variety

  11. Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors. Publishable Final Activity Report

    Kuijper, J.C., E-mail: kuijper@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Somers, J.; Van Den Durpel, L.; Chauvet, V.; Cerullo, N.; Cetnar, J.; Abram, T.; Bakker, K.; Bomboni, E.; Bernnat, W.; Domanska, J.G.; Girardi, E.; De Haas, J.B.M.; Hesketh, K.; Hiernaut, J.P.; Hossain, K.; Jonnet, J.; Kim, Y.; Kloosterman, J.L.; Kopec, M.; Murgatroyd, J.; Millington, D.; Lecarpentier, D.; Lomonaco, G.; McEachern, D.; Meier, A.; Mignanelli, M.; Nabielek, H.; Oppe, J.; Petrov, B.Y.; Pohl, C.; Ruetten, H.J.; Schihab, S.; Toury, G.; Trakas, C.; Venneri, F.; Verfondern, K.; Werner, H.; Wiss, T.; Zakova, J.

    2010-11-15

    The PUMA project -the acronym stands for 'Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors'- was a Specific Targeted Research Project (STREP) within the EURATOM 6th Framework Program (EU FP6). The PUMA project ran from September 1, 2006, until August 31, 2009, and was executed by a consortium of 14 European partner organisations and one from the USA. This report serves 2 purposes. It is both the 'Publishable Final Activity Report' and the 'Final (Summary) Report', describing, per Work Package, the specific objectives, research activities, main conclusions, recommendations and supporting documents. PUMA's main objective was to investigate the possibilities for the utilisation and transmutation of plutonium and especially minor actinides in contemporary and future (high temperature) gas-cooled reactor designs, which are promising tools for improving the sustainability of the nuclear fuel cycle. This contributes to the reduction of Pu and MA stockpiles, and also to the development of safe and sustainable reactors for CO{sub 2}-free energy generation. The PUMA project has assessed the impact of the introduction of Pu/MA-burning HTRs at three levels: fuel and fuel performance (modelling), reactor (transmutation performance and safety) and reactor/fuel cycle facility park. Earlier projects already indicated favourable characteristics of HTRs with respect to Pu burning. So, core physics of Pu/MA fuel cycles for HTRs has been investigated to study the CP fuel and reactor characteristics and to assure nuclear stability of a Pu/MA HTR core, under both normal and abnormal operating conditions. The starting point of this investigation comprised the two main contemporary HTR designs, viz. the pebble-bed type HTR, represented by the South-African PBMR, and hexagonal block type HTR, represented by the GT-MHR. The results (once again) demonstrate the flexibility of the contemporary (and near future) HTR

  12. Radiofrequency ablation using a new type of internally cooled electrode with an adjustable active tip: An experimental study in ex vivo bovine and in vivo porcine livers

    Purpose: The aims of this study were to evaluate the performance of radiofrequency (RF) ablation using a new type of internally cooled RF electrode with an adjustable active tip in an ex vivo bovine liver model and to determine if adjustment of the active tip length makes a significant difference in the size of ablation zone in an in vivo porcine liver model. Materials and methods: We performed ex vivo experiments by producing 100 RF ablation zones in 40 extracted bovine livers using a new type of RF electrode that had an adjustable active tip (adjustable electrode) (n = 50) and a conventional internally cooled electrode (conventional electrode) (n = 50). We also performed an in vivo study with the induction of 30 RF ablation zones in ten living porcine livers using the adjustable electrode with 2 cm (n = 15) and 3 cm (n = 15) active tip adjustments. The size (three perpendicular diameters), volume and ratio of the two axes of the ablation zone were macroscopically evaluated and were compared. Results: For the ex vivo study using a 2 cm and 3 cm active tip, there was no significant difference in ablation performance between the use of conventional and adjustable electrodes. For the use of the conventional and adjustable electrodes with 2 cm active tip, respectively, the volume was 10.75 ± 3.43 cm3 versus 10.64 ± 3.25 cm3 and the ratio of the two axes was 1.24 ± 0.16 versus 1.30 ± 0.17; p > 0.05. For the use of the conventional and adjustable electrodes with 3 cm active tip, respectively, the volume was 21.17 ± 4.09 cm3 versus 21.48 ± 3.51 cm3 and the ratio of the two axes was 1.28 ± 0.12 versus 1.28 ± 0.07; p > 0.05. For the in vivo study using the adjustable electrode, the ablation volume with the 2 cm adjustment was significantly smaller as compared to the 3 cm adjustment (5.29 ± 2.22 cm3 versus 13.44 ± 4.25 cm3; p 0.05). Conclusion: Using a new type of internally cooled RF electrode, we could induce different volumes of the RF ablation zone by means of

  13. Radiofrequency ablation using a new type of internally cooled electrode with an adjustable active tip: An experimental study in ex vivo bovine and in vivo porcine livers

    Cha, Jihoon [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Gangnam-gu, Seoul 135-710 (Korea, Republic of); Kim, Young-sun, E-mail: youngskim@skku.edu [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Gangnam-gu, Seoul 135-710 (Korea, Republic of); Rhim, Hyunchul; Lim, Hyo K.; Choi, Dongil; Lee, Min Woo [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Gangnam-gu, Seoul 135-710 (Korea, Republic of)

    2011-03-15

    Purpose: The aims of this study were to evaluate the performance of radiofrequency (RF) ablation using a new type of internally cooled RF electrode with an adjustable active tip in an ex vivo bovine liver model and to determine if adjustment of the active tip length makes a significant difference in the size of ablation zone in an in vivo porcine liver model. Materials and methods: We performed ex vivo experiments by producing 100 RF ablation zones in 40 extracted bovine livers using a new type of RF electrode that had an adjustable active tip (adjustable electrode) (n = 50) and a conventional internally cooled electrode (conventional electrode) (n = 50). We also performed an in vivo study with the induction of 30 RF ablation zones in ten living porcine livers using the adjustable electrode with 2 cm (n = 15) and 3 cm (n = 15) active tip adjustments. The size (three perpendicular diameters), volume and ratio of the two axes of the ablation zone were macroscopically evaluated and were compared. Results: For the ex vivo study using a 2 cm and 3 cm active tip, there was no significant difference in ablation performance between the use of conventional and adjustable electrodes. For the use of the conventional and adjustable electrodes with 2 cm active tip, respectively, the volume was 10.75 {+-} 3.43 cm{sup 3} versus 10.64 {+-} 3.25 cm{sup 3} and the ratio of the two axes was 1.24 {+-} 0.16 versus 1.30 {+-} 0.17; p > 0.05. For the use of the conventional and adjustable electrodes with 3 cm active tip, respectively, the volume was 21.17 {+-} 4.09 cm{sup 3} versus 21.48 {+-} 3.51 cm{sup 3} and the ratio of the two axes was 1.28 {+-} 0.12 versus 1.28 {+-} 0.07; p > 0.05. For the in vivo study using the adjustable electrode, the ablation volume with the 2 cm adjustment was significantly smaller as compared to the 3 cm adjustment (5.29 {+-} 2.22 cm{sup 3} versus 13.44 {+-} 4.25 cm{sup 3}; p < 0.05) with no statistical difference for the ratio of the two axes (1.44 {+-} 0

  14. A very cool cooling system

    Antonella Del Rosso

    2015-01-01

    The NA62 Gigatracker is a jewel of technology: its sensor, which delivers the time of the crossing particles with a precision of less than 200 picoseconds (better than similar LHC detectors), has a cooling system that might become the precursor to a completely new detector technique.   The 115 metre long vacuum tank of the NA62 experiment. The NA62 Gigatracker (GTK) is composed of a set of three innovative silicon pixel detectors, whose job is to measure the arrival time and the position of the incoming beam particles. Installed in the heart of the NA62 detector, the silicon sensors are cooled down (to about -20 degrees Celsius) by a microfluidic silicon device. “The cooling system is needed to remove the heat produced by the readout chips the silicon sensor is bonded to,” explains Alessandro Mapelli, microsystems engineer working in the Physics department. “For the NA62 Gigatracker we have designed a cooling plate on top of which both the silicon sensor and the...

  15. Cooling systems

    Progress on the thermal effects project is reported with regard to physiology and distribution of Corbicula; power plant effects studies on burrowing mayfly populations; comparative thermal responses of largemouth bass from northern and southern populations; temperature selection by striped bass in Cherokee Reservoir; fish population studies; and predictive thermoregulation by fishes. Progress is also reported on the following; cause and ecological ramifications of threadfin shad impingement; entrainment project; aquaculture project; pathogenic amoeba project; and cooling tower drift project

  16. Electronic cooling using thermoelectric devices

    Zebarjadi, M., E-mail: m.zebarjadi@rutgers.edu [Department of Mechanical and Aerospace Engineering, Rutgers University, Piscataway, New Jersey 08854 (United States); Institute of Advanced Materials, Devices, and Nanotechnology, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2015-05-18

    Thermoelectric coolers or Peltier coolers are used to pump heat in the opposite direction of the natural heat flux. These coolers have also been proposed for electronic cooling, wherein the aim is to pump heat in the natural heat flux direction and from hot spots to the colder ambient temperature. In this manuscript, we show that for such applications, one needs to use thermoelectric materials with large thermal conductivity and large power factor, instead of the traditionally used high ZT thermoelectric materials. We further show that with the known thermoelectric materials, the active cooling cannot compete with passive cooling, and one needs to explore a new set of materials to provide a cooling solution better than a regular copper heat sink. We propose a set of materials and directions for exploring possible materials candidates suitable for electronic cooling. Finally, to achieve maximum cooling, we propose to use thermoelectric elements as fins attached to copper blocks.

  17. Shivering and tachycardic responses to external cooling in mice are substantially suppressed by TRPV1 activation but not by TRPM8 inhibition.

    Feketa, Viktor V; Balasubramanian, Adithya; Flores, Christopher M; Player, Mark R; Marrelli, Sean P

    2013-11-01

    Mild decrease of core temperature (32-34°C), also known as therapeutic hypothermia, is a highly effective strategy of neuroprotection from ischemia and holds significant promise in the treatment of stroke. However, induction of hypothermia in conscious stroke patients is complicated by cold-defensive responses, such as shivering and tachycardia. Although multiple thermoregulatory responses may be altered by modulators of thermosensitive ion channels, TRPM8 (transient receptor potential melastatin 8) and TRPV1 (TRP vanilloid 1), it is unknown whether these agents affect cold-induced shivering and tachycardia. The current study aimed to determine the effects of TRPM8 inhibition and TRPV1 activation on the shivering and tachycardic responses to external cooling. Conscious mice were treated with TRPM8 inhibitor compound 5 or TRPV1 agonist dihydrocapsaicin (DHC) and exposed to cooling at 10°C. Shivering was measured by electromyography using implanted electrodes in back muscles, tachycardic response by electrocardiography, and core temperature by wireless transmitters in the abdominal cavity. The role of TRPM8 was further determined using TRPM8 KO mice. TRPM8 ablation had no effect on total electromyographic muscle activity (vehicle: 24.0 ± 1.8; compound 5: 23.8 ± 2.0; TRPM8 KO: 19.7 ± 1.9 V·s/min), tachycardia (ΔHR = 124 ± 31; 121 ± 13; 121 ± 31 beats/min) and drop in core temperature (-3.6 ± 0.1; -3.4 ± 0.4; -3.6 ± 0.5°C) during cold exposure. TRPV1 activation substantially suppressed muscle activity (vehicle: 25.6 ± 3.0 vs. DHC: 5.1 ± 2.0 V·s/min), tachycardia (ΔHR = 204 ± 25 vs. 3 ± 35 beats/min) and produced a profound drop in core temperature (-2.2 ± 0.6 vs. -8.9 ± 0.6°C). In conclusion, external cooling-induced shivering and tachycardia are suppressed by TRPV1 activation, but not by TRPM8 inhibition. This suggests that TRPV1 agonists may be combined with external physical cooling to achieve more rapid and effective hypothermia. PMID

  18. Solar heating and cooling of buildings: activities of the private sector of the building community and its perceived needs relative to increased activity

    1976-01-01

    A description of the state of affairs existing in the private sector of the building community between mid-1974 and mid-1975 with regard to solar heating and cooling of buildings is presentd. Also, information on the needs perceived by the private sector with regard to governmental actions (besides research) required to induce widespread application of solar energy for the heating and cooling of buildings is given. The information is based on surveys, data obtained at workshops, sales literature of manufacturers, symposia, and miscellaneous correspondence. Selected interests and projects of individuals and organizations are described. (WHK)

  19. The use of copper alloy CuCrZr as a structural material for actively cooled plasma facing and in vessel components

    Lipa, M. [CEA/Cadarache-DSM/DRFC, F-13108 Saint Paul Lez Durance (France)]. E-mail: manfred.lipa@cea.fr; Durocher, A. [CEA/Cadarache-DSM/DRFC, F-13108 Saint Paul Lez Durance (France); Tivey, R. [ITER Garching Joint Work Site, D-85748 Garching (Germany); Huber, Th. [Plansee AG, A-6600 Reutte (Austria); Schedler, B. [Plansee AG, A-6600 Reutte (Austria); Weigert, J. [PTR Praezisionstechnik GmbH, D-63461 Maintal-Doernigheim (Germany)

    2005-11-15

    This paper presents our experience with precipitation hardened CuCrZr in the fabrication of actively cooled components for Tore Supra (toroidal pump limiter fingers, guard limiter heat sink hollow-profiles, ripple protection tubes, endoscope heads) and JET high heat flux elements for the beam-lines. The supposed interplay phenomenon between CuCrZr procurement, component geometry and welding procedure is discussed. The associated mechanical characterisation of materials from different suppliers and component joinings, focused especially on CuCrZr-CuCrZr fusion weldings using electron beams (EB), is presented.

  20. Cooling tower

    The proposal concerns the reinforcement of a cooling tower made of reinforced concrete, which has a dish-shaped supporting structure and has ribs running in the vertical direction. In order to reduce the cost for fitting the reinforcement, the dish-shaped supporting structure is made wholly or partly as an anisotropic dish. By this construction of the reinforcement (spatial grating with different thickness of beam reinforcement of vertical ribs and of the circular beams provided in the dish, site reinforcement of the areas between the beams) one achieves the anisotropy of the dish. The fixing of constructional steel mats as site reinforcement is advantageous. (UWI)

  1. Cool snacks

    Grunert, Klaus G; Brock, Steen; brunsø, karen;

    2016-01-01

    product requires an interdisciplinary effort where researchers with backgrounds in psychology, anthropology, media science, philosophy, sensory science and food science join forces. We present the COOL SNACKS project, where such a blend of competences was used first to obtain thorough insight into young...... people's snacking behaviour and then to develop and test new, healthier snacking solutions. These new snacking solutions were tested and found to be favourably accepted by young people. The paper therefore provides a proof of principle that the development of snacks that are both healthy and attractive...

  2. Solar Heating and Cooling of Buildings: Activities of the Private Sector of the Building Community and Its Perceived Needs Relative to Increased Activity.

    National Academy of Sciences - National Research Council, Washington, DC. Committee on Solar Energy in the Heating and Cooling of Buildings.

    This report is essentially a collection of information gathered from a broad cross-section of the building community that provides a description of the state of affairs existing mid-1974 through mid-1975 in the private sector of the building community with regard to solar heating and cooling of buildings. The report additionally contains…

  3. ATLAS - Liquid Cooling Systems

    Bonneau, P.

    1998-01-01

    Photo 1 - Cooling Unit - Side View Photo 2 - Cooling Unit - Detail Manifolds Photo 3 - Cooling Unit - Rear View Photo 4 - Cooling Unit - Detail Pump, Heater and Exchanger Photo 5 - Cooling Unit - Detail Pump and Fridge Photo 6 - Cooling Unit - Front View

  4. The MK III actively cooled duct liner for the JET neutral beam line: Thermo-mechanical performance and lifetime estimation

    This paper describes the analyses performed to investigate and validate the proposed design for the updated JET MKIII duct side liner, which will replace the present inertial cooled one in the frame of the EP2 neutral beam enhancement project. The thermal-hydraulic and thermo-mechanical performance of a duct liner's generic module, under various loading scenarios has been assessed. Due to difference in scale between a generic liner module length and the relevant load bearing section thickness (∼1.2 m against 4 mm) two different scale FE models have been assessed, the first ones to evaluate the overall reactions and displacements and the others to calculate concentrated stresses in the most loaded sections. Conformity to ITER design criteria has been verified for both monotonic and cyclic loads. The effects of fatigue have been considered and an operational life of 8.5 years is predicted for the liner

  5. An electrochemical method for on-line monitoring of biofilm activity in cooling water using the BIoGEORGE trademark probe

    The presence of active microorganisms on piping and components in cooling water systems can have a profound effect on the corrosion performance of such systems. Microbiologically influenced corrosion (MIC) can result in premature failures of critical and support systems, increased downtime of equipment for repairs and maintenance, and increased operating costs associated with mitigation measures. In some cases, MIC has forced premature replacement of tanks, heat exchangers, and piping systems with a severe effect on plant availability. Monitoring methods that alert plant operators that biofilm formation is occurring on pipe work and components permit the operators to initiate mitigation actions before biofouling becomes severe or MIC has occurred. An electrochemical probe to permit on-line monitoring of biofilm activity under power plant or other industrial exposure conditions is under development. This device, the BIoGEORGE trademark electrochemical biofilm monitor, permits on-line evaluations of the effects of biofilm formation upon the surfaces of passive alloys such as stainless steels exposed to cooling water environments. Benchtop experiments have shown that biofilm formation on stainless steel surfaces can be detected by an electrochemical indication well in advance of any visual evidence of biofilm or corrosion on the electrodes. The design of the probe, results of benchtop experiments, and a description of its installation at the Browns Ferry Nuclear Plant are described

  6. Cool visitors

    2006-01-01

    Pictured, from left to right: Tim Izo (saxophone, flute, guitar), Bobby Grant (tour manager), George Pajon (guitar). What do the LHC and a world-famous hip-hop group have in common? They are cool! On Saturday, 1st July, before their appearance at the Montreux Jazz Festival, three members of the 'Black Eyed Peas' came on a surprise visit to CERN, inspired by Dan Brown's Angels and Demons. At short notice, Connie Potter (Head of the ATLAS secretariat) organized a guided tour of ATLAS and the AD 'antimatter factory'. Still curious, lead vocalist Will.I.Am met CERN physicist Rolf Landua after the concert to ask many more questions on particles, CERN, and the origin of the Universe.

  7. Device for cooling down cooling water especially in cooling towers

    A cooling tower is described where water runs over packing plates being cooled by steaming air. In the cooling process a combination of wet and dry cooling is applied, namely by special design of the packing plates which are arranged inclined to the vertical. Spraying device and packing plates are shaped in such a way that the plates are wetted almost on one side only. 13 drawings explain the construction of the device described in detail. (UWI)

  8. Radio Galaxies in Cooling Cores

    Eilek, J A

    2003-01-01

    A currently active radio galaxy sits at the center of almost every strong cooling core. What effect does it have on the cooling core? Could its effect be strong enough to offset the radiative cooling which should be occuring in these cores? In order to answer these questions we need to know how much energy the radio jet carries to the cooling core; but we have no way to measure the jet power directly. We therefore need to understand how the radio source evolves with time, and how it radiates, in order to use the data to determine the jet power. When some simple models are compared to the data, we learn that cluster-center radio galaxies probably are energetically important -- but not necessarily dominant -- in cooling cores.

  9. Improvement of non destructive infrared test bed SATIR for examination of actively cooled tungsten armour Plasma Facing Components

    Highlights: • Non destructive infrared techniques for control ITER like PFCs. • Reflective surface such as W induce a measurement temperature error. • Numerical data processing by evaluation of the local emissivity. • SATIR test bed can control metallic surface with low and variable emissivity. -- Abstract: For steady state (magnetic) thermonuclear fusion devices which need large power exhaust capability and have to withstand heat fluxes in the range 10–20 MW m−2, advanced Plasma Facing Components (PFCs) have been developed. The importance of PFCs for operating tokamaks requests to verify their manufacturing quality before mounting. SATIR is an IR test bed validated and recognized as a reliable and suitable tool to detect cooling defaults on PFCs with CFC armour material. Current tokamak developments implement metallic armour materials for first wall and divertor; their low emissivity causes several difficulties for infrared thermography control. We present SATIR infrared thermography test bed improvements for W monoblocks components without defect and with calibrated defects. These results are compared to ultrasonic inspection. This study demonstrates that SATIR method is fully usable for PFCs with low emissivity armour material

  10. Modeling the Effect of Active Fiber Cooling on the Microstructure of Fiber-Reinforced Metal Matrix Composites

    Nguyen, Nguyen Q.; Peterson, Sean D.; Gupta, Nikhil; Rohatgi, Pradeep K.

    2009-08-01

    A modified pressure infiltration process was recently developed to synthesize carbon-fiber-reinforced aluminum matrix composites. In the modified process, the ends of carbon fibers are extended out of the crucible to induce selective cooling. The process is found to be effective in improving the quality of composites. The present work is focused on determining the effect of the induced conductive heat transfer on the composite system through numerical methods. Due to the axisymmetry of the system, a two-dimensional (2-D) model is studied that can be expanded into three dimensions. The variables in this transient analysis include the fiber radius, fiber length, and melt superheat temperature. The results show that the composite system can be tailored to have a temperature on the fiber surface that is lower than the melt, to promote nucleation on the fiber surface. It is also observed that there is a point of inflection in the temperature profile along the particle/melt interface at which there is no temperature gradient in the radial direction. The information about the inflection point can be used to control the diffusion of solute atoms in the system. The result can be used in determining the optimum fiber volume fraction in metal matrix composite (MMC) materials to obtain the desired microstructure.

  11. A simple method of designing irradiation-, cooling-, and counting time in multi-element neutron activation analysis

    A method was investigated to seek the optimum irradiation-, cooling-, and counting time for economy of time, labor, and cost. For the first step, the terms of the basic equation of induction and decay of radioactivity were grouped into three parts: the terms of time, of proper values to each nuclide, and of variables due to experimental conditions. Then the equation was simplified by taking logarithm, and the values calculated from the equation for the terms of time and the characteristic values of each nuclide were tabulated. The counting time was decided in such a way that the counts of radioactivity of each nuclide fall in a range between minimal and maximal counts which were decided by counting statistics and by the dead time level of the measuring instruments. The calculation was made by simple treatment of the variables of the experimental conditions and of the values found in the prepared tables. An experimental scheme designed by the above method was applied to analysis of an atmospheric ''standard'' reference sample, and the analytical results were compared with those by the experimental scheme by R. Dams and with those obtained by three nuclear laboratories. The comparison showed that the present method made experiments economical in time, labor, and cost of the analysis by shortening the time of measurement to one half of those of R. Dams, leaving the accuracy almost in the same level. (auth.)

  12. Cool Temperatures Reduce Antifungal Activity of Symbiotic Bacteria of Threatened Amphibians – Implications for Disease Management and Patterns of Decline

    Daskin, Joshua H.; Bell, Sara C.; Schwarzkopf, Lin; Ross A. Alford

    2014-01-01

    Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians’ skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus re...

  13. Jet-Cooled Laser Spectroscopy of a Jahn-Teller and Pseudo Jahn-Teller Active Molecule: the Nitrate Radical

    Chen, Ming-Wei; Takematsu, Kana; Okumura, Mitchio; Miller, Terry A.

    2009-06-01

    Well-known as an important intermediate in atmospheric chemistry, the nitrate radical (NO_3) has been extensively studied both experimentally and theoretically. The three energetically lowest electronic states (tilde{X} ^{2}A_{2}^', tilde{A} ^{2}E^'', and tilde{B} ^{2}E^') are strongly coupled by vibronic interactions and hence it is a textbook molecule for understanding the coupling between nearby potential energy surfaces. Such coupling has been treated in considerable detail theoretically. However, corresponding experimental characterization of the interaction is much less detailed. The experimental results primarily consist of IR measurements of vibrational transitions in the ground state. In addition, the electronically forbidden tilde{A}-tilde{X} transition has been observed in ambient temperature CRDS studies. To understand both the Jahn-Teller and pseudo Jahn-Teller coupling in the molecule, further measurements are required with different selection rules and/or higher resolution to resolve the rotational structures of different transitions. In our group, a high-resolution (source Δν≈ 100 MHz in NIR region), jet-cooled CRDS system can be applied to rotationally resolve the electronically forbidden tilde{A}-tilde{X} transition. Furthermore, our high-resolution LIF/SEP system (source Δν≈ 100 MHz) can provide the direct, rotationally resolved measurements of the tilde{B}-tilde{X} and tilde{B}-tilde{A} transitions by operating in the LIF and SEP modes respectively. Such data can provide unambiguous spectral assignments in the tilde{X}, tilde{A} and tilde{B} states. J. F. Stanton, J. Chem. Phys., 126, 134309 (2007) K. Kawaguchi, E. Hirota, T. Ishiwata, and I. Tanaka, J. Chem. Phys., 93, 951 (1990) K. Kawaguchi, T. Ishiwata, E. Hirota, and I. Tanaka, Chem. Phys., 231, 193 (1998) A. Deev, J. Sommar, and M. Okumura, J. Chem. Phys., 122, 224305 (2005) S. Wu, P. Dupré, and T. A. Miller, Phys. Chem. Chem. Phys., 8, 1682, (2006)

  14. Project S'COOL

    Green, Carolyn J.; Chambers, Lin H.

    1998-01-01

    The Students Clouds Observations On-Line or S'COOL project was piloted in 1997. It was created with the idea of using students to serve as one component of the validation for the Clouds and the Earth's Radiant Energy System (CERES) instrument which was launched with the Tropical Rainfall Measuring Mission (TRMM) in November, 1997. As part of NASA's Earth Science Enterprise CERES is interested in the role clouds play in regulating our climate. Over thirty schools became involved in the initial thrust of the project. The CERES instrument detects the location of clouds and identifies their physical properties. S'COOL students coordinate their ground truth observations with the exact overpass of the satellite at their location. Their findings regarding cloud type, height, fraction and opacity as well as surface conditions are then reported to the NASA Langley Distributed Active Archive Center (DAAC). The data is then accessible to both the CERES team for validation and to schools for educational application via the Internet. By March of 1998 ninety-three schools, in nine countries had enrolled in the S'COOL project. Joining the United States participants were from schools in Australia, Canada, France, Germany, Norway, Spain, Sweden, and Switzerland. The project is gradually becoming the global project envisioned by the project s creators. As students obtain the requested data useful for the scientists, it was hoped that students with guidance from their instructors would have opportunity and motivation to learn more about clouds and atmospheric science as well.

  15. Technical Consultation of the International Space Station (ISS) Internal Active Thermal Control System (IATCS) Cooling Water Chemistry

    Gentz, Steven J.; Rotter, Hank A.; Easton, Myriam; Lince, Jeffrey; Park, Woonsup; Stewart, Thomas; Speckman, Donna; Dexter, Stephen; Kelly, Robert

    2005-01-01

    The Internal Active Thermal Control System (IATCS) coolant exhibited unexpected chemical changes during the first year of on-orbit operation following the launch and activation in February 2001. The coolant pH dropped from 9.3 to below the minimum specification limit of 9.0, and re-equilibrated between 8.3 and 8.5. This drop in coolant pH was shown to be the result of permeation of CO2 from the cabin into the coolant via Teflon flexible hoses which created carbonic acid in the fluid. This unexpected diffusion was the result of having a cabin CO2 partial pressure higher than the ground partial pressure (average 4.0 mmHg vs. less than 0.2 mmHg). This drop in pH was followed by a concurrent increasing coolant nickel concentration. No other metal ions were observed in the coolant and based on previous tests, the source of nickel ion was thought to be the boron nickel (BNi) braze intermetallics used in the construction of HXs and cold plates. Specifically, BNi2 braze alloy was used for the IATCS IFHX and BNi3 braze alloy was used for the IATCS Airlock Servicing and Performance Checkout Unit (SPCU) HX and cold plates. Given the failure criticality of the HXs, a Corrosion Team was established by the IATCS CWG to determine the impact of the nickel corrosion on hardware performance life.

  16. Heat Transfer Augmentation for Electronic Cooling

    Suabsakul Gururatana

    2012-01-01

    Full Text Available Problem statement: The performance of electronic devices has been improving along with the rapid technology development. Cooling of electronic systems is consequently essential in controlling the component temperature and avoiding any hot spot. The study aims to review the present electronic cooling methods which are widely used in electronic devices. Approach: There are several methods to cool down the electronics components such as the pin-fin heat sink, confined jet impingement, heat pipe, micro heat sink and so on. Results: The cooling techniques can obviously increase heat transfer rate. Nonetheless, for active and passive cooling methods the pressure drop could extremely rise, when the heat transfer rate is increased. Conclusion: When the cooling techniques are used, it is clearly seen that the heat transfer increases with pressure drop. To avoid excessive expense due to high pressure drop, optimization method is required to obtain optimum cost and cooling rate.

  17. Hybrid radiator cooling system

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  18. The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

    Danielson, A L R; Alexander, D M; Brandt, W N; Luo, B; Miller, N; Xue, Y Q; Stott, J P

    2012-01-01

    We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z~0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the ~4 Ms CDF-S and ~2 Ms CDF-N and z = 0.1-0.6 in the ~250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keV to B-band luminosity ratio (L_X/L_B proportional to [1 + z]^1.2) since z~1.2, implying that some heating mechanism preve...

  19. Experimental study on a transpiration cooling thermal protection system

    2010-01-01

    Transpiration cooling thermal protection systems (TPS) are investigated for potential applications in hypersonic and re-entry vehicles,which are subjected to the severe aerodynamic heating environment. In this paper a transpiration cooling thermal protection system was designed and manufactured,and an experiment platform with radiant heating at the bottom as heat source was developed. The cooling capacity of the transpiration cooling TPS was experimentally investigated. By combining transpiration cooling method with traditional TPS,the heat load capability of the TPS can be improved. The structure temperature with active cooling applied was much lower than that without active cooling applied under the same heat load as well as the heat load increased with active cooling than the one without active cooling for the same structure temperature. The experimental results showed that at 5800 s,the temperature of inner structure was 100°C with active cooling applied compared to 500°C without active cooling applied,then the temperature increased and reached to 360°C at 8300 s. Heat load of this transpiration cooling TPS can be increased by over 70% as compared to the passion one and the cooling capability of the transpiration TPS was about 1700 kJ/kg. The results can provide fundamental data for developing the transpiration cooling TPS.

  20. Water Activities in Laxemar Simpevarp. Clab/encapsulation facility (Clink) - removal of groundwater, collection of cooling water from the sea and the construction of day water pond

    This report is an appendix to an Environmental Impact Assessment that accompanies a permit application according to the Swedish Environmental Code. The report concerns water operations (Chapter 11 in the Environmental Code) associated with construction of an encapsulation plant in direct connection to SKB's existing Clab facility on the Simpevarp peninsula in the Municipality of Oskarshamn (the report is also included in the permit application according to the Nuclear Activities Act). Moreover, the report deals with water operations associated with the operation of the integrated facility, which is named Clink. Specifically, the water operations that are treated in the report include diversion of groundwater, withdrawal of cooling water from the sea, and construction of a storm-water treatment pond. There are valid permits regarding diversion of groundwater and withdrawal of cooling water for the current facility and activities at Clab. It is presupposed that the cooling-water withdrawal from the sea to Clink can be handled within the limits of the valid Clab permit. The diversion of groundwater from Clink may be somewhat larger compared to the present diversion from Clab. The increase is due to a relatively small, additional rock shaft for the encapsulation plant, adjacent to the current surface facility and above one of the two existing rock caverns (Clab 1). Based on the location of the planned rock shaft (above one of the existing rock caverns) and its small volume, it is judged that the inflow of groundwater during operation of Clink will be only 5-10 percent larger compared to the inflow to the current Clab facility. It is possible that the inflow will be larger during the construction phase, prior to grouting of the shaft. Based on the limited increase of the groundwater inflow and results from the ongoing Clab monitoring programme, it is judged that the construction of the encapsulation plant and the operation of Clink will only lead to very small

  1. Process evaluation of use of high temperature gas-cooled reactors to an ironmaking system based on active carbon recycling energy system

    Reducing coking coal consumption and CO2 emissions by application of iACRES (ironmaking system based on active carbon recycling energy system) was investigated using process flow modeling to show effectiveness of HTGRs (high temperature gas-cooled reactors) adoption to iACRES. Two systems were evaluated: a SOEC (solid oxide electrolysis cell) system using CO2 electrolysis and a RWGS (reverse water-gas shift reaction) system using RWGS reaction with H2 produced by iodine-sulfur process. Both reduction of the coking coal consumption and CO2 emissions were greater in the RWGS system than those in the SOEC system. It was the reason of the result that excess H2 not consumed in the RWGS reaction was used as reducing agent in the blast furnace as well as CO. Heat balance in the HTGR, SOEC and RWGS modules were evaluated to clarify process components to be improved. Optimization of the SOEC temperature was desired to reduce Joule heat input for high efficiency operation of the SOEC system. Higher H2 production thermal efficiency in the IS process for the RWGS system is effective for more efficient HTGR heat utilization. The SOEC system was able to utilize HTGR heat to reduce CO2 emissions more efficiently by comparing CO2 emissions reduction per unit heat of the HTGR. (author)

  2. System for cooling a cabinet

    Smith, Anders; Bahl, Christian; Linderoth, Søren

    2015-01-01

    The present disclosure relates to a cooling system comprising an active magnetic regenerator having a cold side and a hot side, a hot side heat exchanger connected to the hot side of the magnetic regenerator, one or more cold side heat exchangers, and a cold store reservoir comprising a volume of heat transfer fluid and connected between said one or more cold side heat exchangers and the cold side of the magnetic regenerator, wherein the cooling system is configured to provide a first flow cy...

  3. Elastocaloric cooling device: Materials and modeling

    Tusek, Jaka; Engelbrecht, Kurt; Pryds, Nini; Mikkelsen, Lars Pilgaard

    was demonstrated in Ni-Ti-based, Cu-based as well as Fe-based shape memory alloys. Although these studies showed a great potential of the elastocaloric effect, there has not yet been much activities on development of elastocaloric cooling devices. Some ideas on elastocaloric cooling device have...

  4. Cooling Technology for Large Space Telescopes

    DiPirro, Michael; Cleveland, Paul; Durand, Dale; Klavins, Andy; Muheim, Daniella; Paine, Christopher; Petach, Mike; Tenerelli, Domenick; Tolomeo, Jason; Walyus, Keith

    2007-01-01

    NASA's New Millennium Program funded an effort to develop a system cooling technology, which is applicable to all future infrared, sub-millimeter and millimeter cryogenic space telescopes. In particular, this technology is necessary for the proposed large space telescope Single Aperture Far-Infrared Telescope (SAFIR) mission. This technology will also enhance the performance and lower the risk and cost for other cryogenic missions. The new paradigm for cooling to low temperatures will involve passive cooling using lightweight deployable membranes that serve both as sunshields and V-groove radiators, in combination with active cooling using mechanical coolers operating down to 4 K. The Cooling Technology for Large Space Telescopes (LST) mission planned to develop and demonstrate a multi-layered sunshield, which is actively cooled by a multi-stage mechanical cryocooler, and further the models and analyses critical to scaling to future missions. The outer four layers of the sunshield cool passively by radiation, while the innermost layer is actively cooled to enable the sunshield to decrease the incident solar irradiance by a factor of more than one million. The cryocooler cools the inner layer of the sunshield to 20 K, and provides cooling to 6 K at a telescope mounting plate. The technology readiness level (TRL) of 7 will be achieved by the active cooling technology following the technology validation flight in Low Earth Orbit. In accordance with the New Millennium charter, tests and modeling are tightly integrated to advance the technology and the flight design for "ST-class" missions. Commercial off-the-shelf engineering analysis products are used to develop validated modeling capabilities to allow the techniques and results from LST to apply to a wide variety of future missions. The LST mission plans to "rewrite the book" on cryo-thermal testing and modeling techniques, and validate modeling techniques to scale to future space telescopes such as SAFIR.

  5. Biomedical Application of Aerospace Personal Cooling Systems

    Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Webbon, Bruce W.; Kliss, Mark (Technical Monitor)

    1997-01-01

    Personal thermoregulatory systems which are used by astronauts to alleviate thermal stress during extravehicular activity have been applied to the therapeutic management of multiple sclerosis. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive and two active cooling vests and to measure the body temperature and circulatory changes produced by each cooling vest configuration. The MicroClimate Systems and the Life Enhancement Tech(LET) lightweight liquid cooling vests, the Steele Vest and LET's Zipper Front Garment were used to cool the chest region of 10 male and female subjects (25 to 55 yr.) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approx.22C), were tested for 60 min. with the cooling system operated at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. In general, the male and female subjects' oral and ear temperature responses to cooling were similar for all vest configurations tested. Oral temperatures during the recovery period were significantly (Pcooling and recovery periods.

  6. Preliminary design package for solar heating and cooling systems

    1978-01-01

    Summarized preliminary design information on activities associated with the development, delivery and support of solar heating and cooling systems is given. These systems are for single family dwellings and commercial applications. The heating/cooling system use a reversible vapor compression heat pump that is driven in the cooling mode by a Rankine power loop, and in the heating mode by a variable speed electric motor. The heating/cooling systems differ from the heating-only systems in the arrangement of the heat pump subsystem and the addition of a cooling tower to provide the heat sink for cooling mode operation.

  7. Radiant Floor Cooling Systems

    Olesen, Bjarne W.

    2008-01-01

    In many countries, hydronic radiant floor systems are widely used for heating all types of buildings such as residential, churches, gymnasiums, hospitals, hangars, storage buildings, industrial buildings, and smaller offices. However, few systems are used for cooling.This article describes a floo...... cooling system that includes such considerations as thermal comfort of the occupants, which design parameters will influence the cooling capacity and how the system should be controlled. Examples of applications are presented....

  8. Water cooled nuclear reactor

    The description is given of a water cooled nuclear reactor comprising a core, cooling water that rises through the core, vertical guide tubes located inside the core and control rods vertically mobile in the guide tubes. In this reactor the cooling water is divided into a first part introduced at the bottom end of the core and rising through it and a second part introduced at the top end of the guide tubes so as to drop in them

  9. Initial Cooling Experiment (ICE)

    Photographic Service

    1978-01-01

    In 1977, in a record-time of 9 months, the magnets of the g-2 experiment were modified and used to build a proton/antiproton storage ring: the "Initial Cooling Experiment" (ICE). It served for the verification of the cooling methods to be used for the "Antiproton Project". Stochastic cooling was proven the same year, electron cooling followed later. Also, with ICE the experimental lower limit for the antiproton lifetime was raised by 9 orders of magnitude: from 2 microseconds to 32 hours. For its previous life as g-2 storage ring, see 7405430. More on ICE: 7711282, 7809081, 7908242.

  10. Emergency core cooling device

    The present invention provides an emergency core cooling device without using a reactor core spray device, in which the reactor core of a BWR type reactor is cooled effectively and certainly by flooding of the reactor core. That is, the emergency core cooling device comprises a high pressure core water injection system as an emergency core cooling system (ECCS) for cooling the inside of the reactor core upon loss of coolants accident (LOCA). By means of the high pressure core water injection system, water is injected from a condensate storage vessel or a suppression pool to the inside of the reactor core shroud upon LOCA. Accordingly, the reactor core is cooled effectively by reactor core flooding. In this device, cooling water can be injected to the inside of the reactor core shroud by means of the high pressure core injection system upon LOCA in which the coolants are discharged from the outside of the reactor core shroud. On the other hand, upon LOCA in which the coolants are discharged from the inside of the reactor core shroud, the cooling water can be supplied to the reactor core by means of a cooling system upon reactor isolation which injects water to the outside of the reactor core or a low pressure water injection system. (I.S.)

  11. Air cooling system

    A procedure for cooling the steam from a turbine used in conjunction with a power nuclear reactor has been described in the main patent. According to said procedure, use is made of a circuit where a two-phase mixture is circulated, said closed circuit connecting the turbine condenser to a cooling tower. According to the present addition patent, the cooling structure is provided with cooling fins previously hollowed in view of increasing the interface between the fluid and said structure, which improves the performance of the system

  12. Stacking with stochastic cooling

    Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105 the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some considerations to the 'azimuthal' schemes

  13. Design of a rapidly cooled cryogenic mirror

    Plummer, Ron; Hsu, Ike

    1993-01-01

    The paper discusses the design, analysis, and testing of a rapidly cooled beryllium cryogenic mirror, which is the primary mirror in the four-element optical system for the Long Wavelength Infrared Advanced Technology Seeker. The mirror is shown to meet the requirement of five minutes for cooling to cryogenic operating temperature; it also maintains its optical figure and vacuum integrity and meets the nuclear specification. Results of a detailed thermal analysis on the mirror showed that, using nitrogen gas at 80 K as coolant, the front face of the mirror can be cooled from an initial temperature of 300 K to less than 90 K within five minutes. In a vacuum chamber, using liquid nitrogen as coolant, the mirror can be cooled to 80 K within 1.5 min. The mirror is well thermally insulated, so that it can be maintained at less than its operating temperature for a long time without active cooling.

  14. Muon Ionization Cooling Experiment (MICE)

    Zisman, M S

    2004-01-01

    There is presently considerable activity worldwide on developing the technical capability for a “neutrino factory” based on a muon storage ring and, a muon collider. Muons are obtained from the decay of pions produced when an intense proton beam hits a high-Z target, so the initial muon beam has a large 6-dimensional phase space. To increase the muons’ phase-space density, we use ionization cooling, which is based on energy loss in an absorber, followed by re-acceleration with high-gradient, normal-conducting RF cavities. The absorber of choice is liquid hydrogen to minimize multiple scattering. A superimposed solenoidal focusing channel contains the muons. Although the physics is straightforward, the technology and its implementation are not. The international MICE collaboration will demonstrate ionization cooling of a muon beam in a short section of a typical cooling channel. The experiment is approved for operation at Rutherford Appleton Lab. We will measure the cooling effect...

  15. Theoretical Analysis of Radiative Cooling for Mobile and Embedded Systems

    De Vogeleer, Karel; Memmi, Gerard; Jouvelot, Pierre,; Coelho, Fabien

    2014-01-01

    A new global analytical model of the heat dissipation process that occurs in passively-cooled embedded systems is introduced, and we explicit under what circumstances the traditional assumption that exponential cooling laws apply in such context is valid. Since the power consumption and reliability of microprocessors are highly dependent on temperature, management units need accurate thermal models. Exponential cooling models are justified for actively-cooled systems. Here, we analyze the tra...

  16. Temporary cooling system for critical loads during Recirculation Cooling Water (RCW) system outage

    As part of the Point Lepreau Refurbishment Project, Recirculation Cooling Water (RCW) system will be shutdown for maintenance activity. During the RCW outage, alternate cooling flow for critical heat loads such as Spent Fuel Bay (SFB), D2O vapour dryers and Instrument Air Compressor Coolers will be provided through a temporary cooling system to remove approximately 3MW of heat. This paper describes a practical strategy to build in the temporary cooling system for this project. Major equipment involved, piping modifications required and system reliability analysis are also addressed. (author)

  17. Measure Guideline: Ventilation Cooling

    Springer, D.; Dakin, B.; German, A.

    2012-04-01

    The purpose of this measure guideline on ventilation cooling is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  18. Cooling of electronic equipment

    A. Kristensen, Anders Schmidt

    2003-01-01

    Cooling of electronic equipment is studied. The design size of electronic equipment decrease causing the thermal density to increase. This affect the cooling which can cause for example failures of critical components due to overheating or thermal induced stresses. Initially a pin fin heat sink...

  19. Coherent electron cooling

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  20. The final cool down

    Thursday 29th May, the cool-down of the final sector (sector 4-5) of LHC has begun, one week after the start of the cool-down of sector 1-2. It will take five weeks for the sectors to be cooled from room temperature to 5 K and a further two weeks to complete the cool down to 1.9 K and the commissioning of cryogenic instrumentation, as well as to fine tune the cryogenic plants and the cooling loops of cryostats.Nearly a year and half has passed since sector 7-8 was cooled for the first time in January 2007. For Laurent Tavian, AT/CRG Group Leader, reaching the final phase of the cool down is an important milestone, confirming the basic design of the cryogenic system and the ability to operate complete sectors. “All the sectors have to operate at the same time otherwise we cannot inject the beam into the machine. The stability and reliability of the cryogenic system and its utilities are now very important. That will be the new challenge for the coming months,” he explains. The status of the cool down of ...

  1. Passive evaporative cooling

    Tzoulis, A.

    2011-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Smart & Bioclimatic Design. Passive techniques for cooling are a great way to cope with the energy problem of the present day. This manual introduces passive cooling by evaporation. These methods have been used for many years in traditi

  2. DOAS, Radiant Cooling Revisited

    Hastbacka, Mildred; Dieckmann, John; Bouza, Antonio

    2012-12-01

    The article discusses dedicated outdoor air systems (DOAS) and radiant cooling technologies. Both of these topics were covered in previous ASHRAE Journal columns. This article reviews the technologies and their increasing acceptance. The two steps that ASHRAE is taking to disseminate DOAS information to the design community, available energy savings and the market potential of radiant cooling systems are addressed as well.

  3. Data center cooling method

    Chainer, Timothy J.; Dang, Hien P.; Parida, Pritish R.; Schultz, Mark D.; Sharma, Arun

    2015-08-11

    A method aspect for removing heat from a data center may use liquid coolant cooled without vapor compression refrigeration on a liquid cooled information technology equipment rack. The method may also include regulating liquid coolant flow to the data center through a range of liquid coolant flow values with a controller-apparatus based upon information technology equipment temperature threshold of the data center.

  4. Solar absorption cooling

    Kim, D.-S.

    2007-01-01

    As the world concerns more and more on global climate changes and depleting energy resources, solar cooling technology receives increasing interests from the public as an environment-friendly and sustainable alternative. However, making a competitive solar cooling machine for the market still remain

  5. Gas-cooled reactors

    The present study is the second part of a general survey of Gas Cooled Reactors (GCRs). In this part, the course of development, overall performance and present development status of High Temperature Gas Cooled Reactors (HTCRs) and advances of HTGR systems are reviewed. (author)

  6. Market assessment for active solar heating and cooling products. Category B: a survey of decision-makers in the HVAC marketplace. Final report

    None

    1980-09-01

    A comprehensive evaluation of the market for solar heating and cooling products for new and retrofit markets is reported. The emphasis is on the analysis of solar knowledge among HVAC decision makers and a comprehensive evaluation of their solar attitudes and behavior. The data from each of the following sectors are described and analyzed: residential consumers, organizational and manufacturing buildings, HVAC engineers and architects, builders/developers, and commercial/institutional segments. (MHR)

  7. The development of air cooled condensation systems

    EGI - Contracting/Engineering has had experience with the development of air cooled condensing systems since the 1950's. There are two accepted types of dry cooling systems,the direct and the indirect ones. Due to the fact that the indirect system has several advantages over the direct one, EGI's purpose was to develop an economic, reliable and efficient type of indirect cooling system, both for industrial and power station applications. Apart from system development, the main components of dry cooling plant have been developed as well. These are: the water-to-air heat exchangers; the direct contact (DC, or jet) condenser; the cooling water circulating pumps and recovery turbines; and the peak cooling/preheating units. As a result of this broad development work which was connected with intensive market activity, EGI has supplied about 50% of the dry cooling plants employed for large power stations all over the world. This means that today the cumulated capacity of power units using Heller type dry cooling systems supplied and contracted by EGI is over 6000 MW

  8. Muon cooling channels

    Parameters of muon cooling channels are discussed that achieve cooling of a muon beam from initial to final emittances in all three degrees of freedom in a given length. Published theories of ionisation cooling yield equilibrium emittances from multiple scattering and energy straggling, and partition numbers. Limits are obtained on the amplitude functions in all three degrees of freedom. Parameters of wedge-shaped absorbers and partition numbers are derived for simultaneous longitudinal and transverse cooling. Limits on length and material of absorbers, and dispersion at the wedge-shaped absorbers are obtained. Parameters are presented for the RF system, e.g. peak voltage, frequency, and stable phase angle. The properties of the magnetic lattice which satisfies the conditions imposed by the longitudinal dynamics are studied. The consequences of changes in the assumed performance of the cooling channel on its parameters are discussed

  9. INITIAL COOLING EXPERIMENT (ICE)

    1978-01-01

    ICE was built in 1977, in a record time of 9 months, using the modified bending magnets of the g-2 muon storage ring. Its purpose was to verify the validity of stochastic and electron cooling for the antiproton project, to be launched in 1978. Already early in 1978, stochastic cooling proved a resounding success, such that the antiproton (p-pbar)project was entirely based on it. Tests of electron cooling followed later: protons of 46 MeV kinetic energy were cooled with an electron beam of 26 kV and 1.3 A. The cage seen prominently in the foreground houses the HV equipment, adjacent to the "cooler" installed in a straight section of the ring. With some modifications, the cooler was later transplanted into LEAR (Low Energy Antiproton Ring) and then, with further modifications, into the AD (Antiproton Decelerator), where it cools antiprotons to this day (2006). See also: 7711282, 7802099, 7908242.

  10. INITIAL COOLING EXPERIMENT (ICE)

    1979-01-01

    ICE was built in 1977, using the modified bending magnets of the g-2 muon storage ring (see 7405430). Its purpose was to verify the validity of stochastic and electron cooling for the antiproton project. Stochastic cooling proved a resounding success early in 1978 and the antiproton project could go ahead, now entirely based on stochastic cooling. Electron cooling was experimented with in 1979. The 26 kV equipment is housed in the cage to the left of the picture, adjacent to the "e-cooler" located in a straight section of the ring. With some modifications, the cooler was later transplanted into LEAR (Low Energy Antiproton Ring) and then, with further modifications, into the AD (Antiproton Decelerator), where it cools antiprotons to this day (2006). See also: 7711282, 7802099, 7809081.

  11. Modeling of hydronic radiant cooling of a thermally homeostatic building using a parametric cooling tower

    Highlights: • Investigated cooling of thermally homeostatic buildings in 7 U.S. cities by modeling. • Natural energy is harnessed by cooling tower to extract heat for building cooling. • Systematically studied possibility and conditions of using cooling tower in buildings. • Diurnal ambient temperature amplitude is taken into account in cooling tower cooling. • Homeostatic building cooling is possible in locations with large ambient T amplitude. - Abstract: A case is made that while it is important to mitigate dissipative losses associated with heat dissipation and mechanical/electrical resistance for engineering efficiency gain, the “architect” of energy efficiency is the conception of best heat extraction frameworks—which determine the realm of possible efficiency. This precept is applied to building energy efficiency here. Following a proposed process assumption-based design method, which was used for determining the required thermal qualities of building thermal autonomy, this paper continues this line of investigation and applies heat extraction approach investigating the extent of building partial homeostasis and the possibility of full homeostasis by using cooling tower in one summer in seven selected U.S. cities. Cooling tower heat extraction is applied parametrically to hydronically activated radiant-surfaces model-buildings. Instead of sizing equipment as a function of design peak hourly temperature as it is done in heat balance design-approach of selecting HVAC equipment, it is shown that the conditions of using cooling tower depend on both “design-peak” daily-mean temperature and the distribution of diurnal range in hourly temperature (i.e., diurnal temperature amplitude). Our study indicates that homeostatic building with natural cooling (by cooling tower alone) is possible only in locations of special meso-scale climatic condition such as Sacramento, CA. In other locations the use of cooling tower alone can only achieve homeostasis

  12. Biomedical Application of Aerospace Personal Cooling Systems

    Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Webbon, Bruce W.; Kliss, Mark (Technical Monitor)

    1997-01-01

    Personal thermoregulatory systems which are used by astronauts to alleviate thermal stress during extravehicular activity have been applied to the therapeutic management of multiple sclerosis. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive and two active cooling vests and to measure the body temperature and circulatory changes produced by each cooling vest configuration. The MicroClimate Systems and the Life Enhancement Tech(LET) lightweight liquid cooling vests, the Steele Vest and LET's Zipper Front Garment were used to cool the chest region of 10 male and female subjects (25 to 55 yr.) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approx.22C), were tested for 60 min. with the cooling system operated at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. In general, the male and female subjects' oral and ear temperature responses to cooling were similar for all vest configurations tested. Oral temperatures during the recovery period were significantly (P<0.05) lower than during the control period, approx. 0.2 - 0.5C, for both men and women wearing any of the four different garments. The corresponding ear temperatures were significantly (P<0.05) decreased approx.0.2 - 0.4C by the end of the recovery period. Compared to the control period, no significant differences were found in rectal temperatures during cooling and

  13. Second sector cool down

    2007-01-01

    At the beginning of July, cool-down is starting in the second LHC sector, sector 4-5. The cool down of sector 4-5 may occasionally generate mist at Point 4, like that produced last January (photo) during the cool-down of sector 7-8.Things are getting colder in the LHC. Sector 7-8 has been kept at 1.9 K for three weeks with excellent stability (see Bulletin No. 16-17 of 16 April 2007). The electrical tests in this sector have got opt to a successful start. At the beginning of July the cryogenic teams started to cool a second sector, sector 4-5. At Point 4 in Echenevex, where one of the LHC’s cryogenic plants is located, preparations for the first phase of the cool-down are underway. During this phase, the sector will first be cooled to 80 K (-193°C), the temperature of liquid nitrogen. As for the first sector, 1200 tonnes of liquid nitrogen will be used for the cool-down. In fact, the nitrogen circulates only at the surface in the ...

  14. MEIC electron cooling program

    Cooling of proton and ion beams is essential for achieving high luminosities (up to above 1034 cm-2s-1) for MEIC, a Medium energy Electron-Ion Collider envisioned at JLab [1] for advanced nuclear science research. In the present conceptual design, we utilize the conventional election cooling method and adopted a multi-staged cooling scheme for reduction of and maintaining low beam emittances [2,3,4]. Two electron cooling facilities are required to support the scheme: one is a low energy (up to 2 MeV) DC cooler installed in the MEIC ion pre-booster (with the proton kinetic energy up to 3 GeV); the other is a high electron energy (up to 55 MeV) cooler in the collider ring (with the proton kinetic energy from 25 to 100 GeV). The high energy cooler, which is based on the ERL technology and a circulator ring, utilizes a bunched electron beam to cool bunched proton or ion beams. To complete the MEIC cooling concept and a technical design of the ERL cooler as well as to develop supporting technologies, an R&D program has been initiated at Jefferson Lab and significant progresses have been made since then. In this study, we present a brief description of the cooler design and a summary of the progress in this cooling R&D

  15. Dry well cooling device

    A plurality of blowing ports with introduction units are disposed to a plurality of ducts in a dry well, and a cooling unit comprising a cooler, a blower and an isolating valve is disposed outside of the dry well. Cooling air and the atmosphere in the dry well are mixed to form a cooling gas and blown into the dry well to control the temperature. Since the cooling unit is disposed outside of the dry well, the maintenance of the cooling unit can be performed even during the plant operation. In addition, since dampers opened/closed depending on the temperature of the atmosphere are disposed to the introduction units for controlling the temperature of the cooling gas, the temperature of the atmosphere in the dry well can be set to a predetermined level rapidly. Since an axial flow blower is used as the blower of the cooling unit, it can be contained in a ventilation cylinder. Then, the atmosphere in the dry well flowing in the ventilation cylinder can be prevented from leaking to the outside. (N.H.)

  16. Terrestrial cooling and solar variability

    Agee, E. M.

    1982-01-01

    Observational evidence from surface temperature records is presented and discussed which suggests a significant cooling trend over the Northern Hemisphere from 1940 to the present. This cooling trend is associated with an increase of the latitudinal gradient of temperature and the lapse rate, as predicted by climate models with decreased solar input and feedback mechanisms. Evidence suggests that four of these 80- to 100-year cycles of global surface temperature fluctuation may have occurred, and in succession, from 1600 to the present. Interpretation of sunspot activity were used to infer a direct thermal response of terrestrial temperature to solar variability on the time scale of the Gleissberg cycle (90 years, an amplitude of the 11-year cycles). A physical link between the sunspot activity and the solar parameter is hypothesized. Observations of sensible heat flux by stationary planetary waves and transient eddies, as well as general circulation modeling results of these processes, were examined from the viewpoint of the hypothesis of cooling due to reduced insolation.

  17. Feedback cooling of currents

    Washburn, Sean

    1989-02-01

    Just as feedback can be used to correct errors in the output voltages of amplifiers, it can also be used to remove noise from the current through a resistor. Such a feedback amplifier behaves as a refrigerator cooling the electrons in a resistor connnected to it. This principle has been recognized since the 1940s but has been largely ignored because the cooling power available from such refrigerators is miniscule. It is pointed out here that the method might be practical for cooling the currents in the microscopic circuits that are typical of modern electrical engineering and recent studies in transport physics.

  18. Cooling System Analysis

    Almeida, Fernando Jorge Gonçalves; Cruz, João Pedro Brás da

    2012-01-01

    ABSTRACT This master thesis report describes the behavior of a cooling system based on the power consumption and power losses during the velocity range. The thesis is a report of the behavior of the cooling system to understand were we having more needs to cold down the system. It was used a excel sheet to describe the values of power, losses and efficiencies of the various components of the cooling. With the excel sheets built we studied various cases in the system to show ...

  19. Personal Cooling System

    1986-01-01

    Cool Head, a personal cooling system for use in heat stress occupations, is a spinoff of a channeled cooling garment for space wear. It is portable and includes a heat exchanger, control display unit, liquid reservoir and temperature control unit. The user can eliminate 40 to 60 percent of his body's heat storage and lower heart rate by 50 to 80 beats a minute. The system is used by the Army, Navy, crop dusting pilots, heavy equipment operators and auto racing drivers and is marketed by Life Enhancement Technologies, LLC. Further applications are under consideration.

  20. Bunched beam stochastic cooling

    Wei, Jie

    1992-09-01

    The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

  1. Bunched beam stochastic cooling

    Wei, Jie.

    1992-01-01

    The scaling laws for bunched-beam stochastic cooling has been derived in terms of the optimum cooling rate and the mixing condition. In the case that particles occupy the entire sinusoidal rf bucket, the optimum cooling rate of the bunched beam is shown to be similar to that predicted from the coasting-beam theory using a beam of the same average density and mixing factor. However, in the case that particles occupy only the center of the bucket, the optimum rate decrease in proportion to the ratio of the bunch area to the bucket area. The cooling efficiency can be significantly improved if the synchrotron side-band spectrum is effectively broadened, e.g. by the transverse tune spread or by using a double rf system.

  2. Sisyphus Cooling of Lithium

    Hamilton, Paul; Kim, Geena; Mukherjee, Biswaroop; Tiarks, Daniel; Müller, Holger

    2013-01-01

    Laser cooling to sub-Doppler temperatures by optical molasses is thought to be inhibited in atoms with unresolved, near-degenerate hyperfine structure in the excited state. We demonstrate that such cooling is possible in one to three dimensions, not only near the standard D2 line for laser cooling, but over a range extending to the D1 line. Via a combination of Sisyphus cooling followed by adiabatic expansion, we reach temperatures as low as 40 \\mu K, which corresponds to atomic velocities a factor of 2.6 above the limit imposed by a single photon recoil. Our method requires modest laser power at a frequency within reach of standard frequency locking methods. It is largely insensitive to laser power, polarization and detuning, magnetic fields, and initial hyperfine populations. Our results suggest that optical molasses should be possible with all alkali species.

  3. CONFERENCE: Electron cooling

    ECOOL 84, held at the Kernforschungszentrum Karlsruhe (KfK) last year, was the first international meeting on electron cooling and related applications and reflected the increasing interest in this area of particle beam physics

  4. Radiant Floor Cooling Systems

    Olesen, Bjarne W.

    2008-01-01

    In many countries, hydronic radiant floor systems are widely used for heating all types of buildings such as residential, churches, gymnasiums, hospitals, hangars, storage buildings, industrial buildings, and smaller offices. However, few systems are used for cooling.This article describes a floo...... cooling system that includes such considerations as thermal comfort of the occupants, which design parameters will influence the cooling capacity and how the system should be controlled. Examples of applications are presented.......In many countries, hydronic radiant floor systems are widely used for heating all types of buildings such as residential, churches, gymnasiums, hospitals, hangars, storage buildings, industrial buildings, and smaller offices. However, few systems are used for cooling.This article describes a floor...

  5. LHC cooling gains ground

    Huillet-Miraton Catherine

    The nominal cryogenic conditions of 1.9 K have been achieved in sectors 5-6 and 7-8. This means that a quarter of the machine has reached the nominal conditions for LHC operation, having attained a temperature of below 2 K (-271°C), which is colder than interstellar space! Elsewhere, the cryogenic system in Sector 8-1 has been filled with liquid helium and cooled to 2K and will soon be available for magnet testing. Sectors 6-7 and 2-3 are being cooled down and cool-down operations have started in Sector 3-4. Finally, preparations are in hand for the cool-down of Sector 1-2 in May and of Sector 4-5, which is currently being consolidated. The LHC should be completely cold for the summer. For more information: http://lhc.web.cern.ch/lhc/Cooldown_status.htm.

  6. Waveguide cooling system

    Chen, B. C. J.; Hartop, R. W. (Inventor)

    1981-01-01

    An improved system is described for cooling high power waveguides by the use of cooling ducts extending along the waveguide, which minimizes hot spots at the flanges where waveguide sections are connected together. The cooling duct extends along substantially the full length of the waveguide section, and each flange at the end of the section has a through hole with an inner end connected to the duct and an opposite end that can be aligned with a flange hole in another waveguide section. Earth flange is formed with a drainage groove in its face, between the through hole and the waveguide conduit to prevent leakage of cooling fluid into the waveguide. The ducts have narrowed sections immediately adjacent to the flanges to provide room for the installation of fasteners closely around the waveguide channel.

  7. Cooling of wood briquettes

    Adžić Miroljub M.

    2013-01-01

    Full Text Available This paper is concerned with the experimental research of surface temperature of wood briquettes during cooling phase along the cooling line. The cooling phase is an important part of the briquette production technology. It should be performed with care, otherwise the quality of briquettes could deteriorate and possible changes of combustion characteristics of briquettes could happen. The briquette surface temperature was measured with an IR camera and a surface temperature probe at 42 sections. It was found that the temperature of briquette surface dropped from 68 to 34°C after 7 minutes spent at the cooling line. The temperature at the center of briquette, during the 6 hour storage, decreased to 38°C.

  8. Stacking with stochastic cooling

    Caspers, Fritz E-mail: Fritz.Caspers@cern.ch; Moehl, Dieter

    2004-10-11

    Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 10{sup 5} the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some

  9. Electron cooling for RHIC

    Electron cooling of completely stripped gold ions 197Au79+ in RHIC is considered for the store energy, γ=108. The optimal parameters of the required electron storage ring are discussed and proposed. The cooling time is calculated as 15 min, which would allow not only to avoid the beam loss due to the intra-beam scattering, but also reduce the transverse emittance and increase the luminosity several times

  10. Cooling with Superfluid Helium

    Lebrun, P

    2014-01-01

    The technical properties of helium II (‘superfluid’ helium) are presented in view of its applications to the cooling of superconducting devices, particularly in particle accelerators. Cooling schemes are discussed in terms of heat transfer performance and limitations. Large-capacity refrigeration techniques below 2 K are reviewed, with regard to thermodynamic cycles as well as process machinery. Examples drawn from existing or planned projects illustrate the presentation. Keywords: superfluid helium, cryogenics

  11. Particle deposition and resuspension in gas-cooled reactors—Activity overview of the two European research projects THINS and ARCHER

    Highlights: • A summary on particle deposition and resuspension experiments is provided. • Similarities between single and multilayer particle deposits are found. • Numerical models for simulation of particle deposits are successfully developed. - Abstract: The deposition and resuspension behaviour of radio-contaminated aerosol particles is a key issue for the safety assessment of depressurization accidents of gas-cooled high temperature reactors. Within the framework of two European research projects, namely Thermal Hydraulics of Innovative Nuclear Systems (THINS) and Advanced High-Temperature Reactors for Cogeneration of Heat and Electricity R&D (ARCHER), a series of investigations was performed to investigate the transport, the deposition and the resuspension of aerosol particles in turbulent flows. The experimental and numerical tests can be subdivided into four different parts: (1) Monolayer particle deposition, (2) Monolayer particle resuspension, (3) Multilayer particle deposition and (4) Multilayer particle resuspension. The experimental results provide a new insight into the formation and removal of aerosol particle deposits in turbulent flows and are used for the development and validation of numerical procedures in gas-cooled reactors. Good agreement was found between the numerical and the experimental results

  12. Alternative Room Cooling System

    Md. Fazle Rabbi

    2015-06-01

    Full Text Available The rapidly growing population results in an increasing demand for much more residential and commercial buildings, which leads to vertical growth of the buildings and needs proper ventilation of those buildings. Natural air ventilation system is not sufficient for conventional building structures. Hence fans and air-conditioners are must to meet the requirement of proper ventilation as well as space conditioning. Globally building sector consumes largest energy in heating, cooling, ventilation and space conditioning. This load can be minimized by the application of solar chimney and modification in building structure for heating, cooling, ventilation and space conditioning. Passive solar cooling is a subject of interest to provide cooling by using the sun, a powerful energy source. This is done for ensuring human comfort in hot climates. ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers defines Comfort as ‘that state of mind which expresses satisfaction with the thermal environment.’ The present paper describes the development of a solar passive cooling system, which can provide thermal cooling throughout the summer season in hot and humid climates. The constructed passive system works on natural convection mode of air. Such system reduces the inside temperature of up to 5°C from the atmospheric temperature. Temperature can further be reduced by the judicious use of night ventilation.

  13. Stacking with Stochastic Cooling

    Caspers, Friedhelm

    2004-01-01

    Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles seen by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly protected from the Schottky noise of the stack. Vice versa the stack has to be efficiently shielded against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 105, the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters)....

  14. Heating and cooling system. [for fatigue test specimens

    Imig, L. A.; Gardner, M. R. (Inventor)

    1982-01-01

    A heating and cooling apparatus capable of cyclic heating and cooling of a test specimen undergoing fatigue testing is discussed. Cryogenic fluid is passed through a block clamped to the speciment to cool the block and the specimen. Heating cartridges penetrate the block to heat the block and the specimen to very hot temperaures. Control apparatus is provided to alternatively activate the cooling and heating modes to effect cyclic heating and cooling between very hot and very cold temperatures. The block is constructed of minimal mass to facilitate the rapid temperature changes.

  15. Comparing Social Stories™ to Cool versus Not Cool

    Leaf, Justin B.; Mitchell, Erin; Townley-Cochran, Donna; McEachin, John; Taubman, Mitchell; Leaf, Ronald

    2016-01-01

    In this study we compared the cool versus not cool procedure to Social Stories™ for teaching various social behaviors to one individual diagnosed with autism spectrum disorder. The researchers randomly assigned three social skills to the cool versus not cool procedure and three social skills to the Social Stories™ procedure. Naturalistic probes…

  16. Environmental assessment of cooling reservoirs

    The environmental impacts, both adverse and beneficial, of cooling reservoirs are compared to cooling towers as an alternative closed cycle cooling system. Generally, the impacts associated with the construction of a cooling reservoir system are greater than for a comparable cooling tower system. Operational impacts are generally greater for cooling towers due to their visual impact, plus icing, fogging, and noise problems. The principle advantages of cooling reservoirs are their lower operating and maintenance costs, greater reliability, greater cooling efficiency, reduced water consumption in areas where cooling water storage is required, and their multiple use potential. A review of pertinent literature on cooling reservoir ecosystems, has revealed that entrainment, thermal, and chemical effects generally result in reduced populations of phytoplankton, zooplankton, and benthos in the vicinity of the power plant discharge. Adverse far field effects are generally less significant and are sometimes stimulatory. The overall effects of a power plant on the fish populations of cooling reservoirs appear to be minor. Based on the thermal characteristics of a model 6400 acre cooling reservoir with four 1150 MWe reactors, the ecological characteristics of the reservoir were predicted. The multiple use possibilities of cooling reservoirs provide their most significant beneficial aspect when compared to cooling towers. In addition, the cage culture of food fishes in cooling reservoirs provides an economical and practical method of commercially utilizing the waste heat discharged by power plants. For many areas of the country, cooling reservoirs appear to provide an environmentally and socially desirable alternative to cooling towers

  17. High Performance Torso Cooling Garment

    Conger, Bruce; Makinen, Janice

    2016-01-01

    The concept proposed in this paper is to improve thermal efficiencies of the liquid cooling and ventilation garment (LCVG) in the torso area, which could facilitate removal of LCVG tubing from the arms and legs, thereby increasing suited crew member mobility. EVA space suit mobility in micro-gravity is challenging, and it becomes even more challenging in the gravity of Mars. By using shaped water tubes that greatly increase the contact area with the skin in the torso region of the body, the heat transfer efficiency can be increased. This increase in efficiency could provide the required liquid cooling via torso tubing only; no arm or leg LCVG tubing would be required. Benefits of this approach include increased crewmember mobility, enhanced evaporation cooling, increased comfort during Mars EVA tasks, and easing of the overly dry condition in the helmet associated with the Advanced Extravehicular Mobility Unit (EMU) ventilation loop currently under development. This report describes analysis and test activities performed to evaluate the potential improvements to the thermal performance of the LCVG. Analyses evaluated potential tube shapes for improving the thermal performance of the LCVG. The analysis results fed into the selection of flat flow strips to improve thermal contact with the skin of the suited test subject. Testing of small segments was performed to compare thermal performance of the tubing approach of the current LCVG to the flat flow strips proposed as the new concept. Results of the testing is presented along with recommendations for future development of this new concept.

  18. Measuring the coolness of interactive products: the COOL questionnaire

    Bruun, Anders; Raptis, Dimitrios; Kjeldskov, Jesper;

    2016-01-01

    is the COOL questionnaire. We based the creation of the questionnaire on literature suggesting that perceived coolness is decomposed to outer cool (the style of a product) and inner cool (the personality characteristics assigned to it). In this paper, we focused on inner cool, and we identified 11...... inner cool characteristics. These were used to create an initial pool of question items and 2236 participants were asked to assess 16 mobile devices. By performing exploratory and confirmatory factor analyses, we identified three factors that can measure the perceived inner coolness of interactive...

  19. High temperature gas-cooled reactor technology

    The high temperature gas-cooled reactor (HTGR) with a direct cycle helium system has drawn attention as the next generation nuclear power plant that is closest to commercialization. Fuji Electric participated in the design, manufacture and construction of JAPCO's Tokai-1 plant, a 'Colder Hall' type reactor, which was the first commercial nuclear power plant in Japan, and JAERI's high temperature engineering test reactor (HTTR), which was the first high temperature gas-cooled reactor in Japan. Fuji Electric, a pioneer of gas-cooled reactors, worked on the design, construction and development of these reactors. This paper provides brief descriptions of the air-cooled spent fuel storage system of the HTTR, material test facilities for the HTTR, and the development of an inherently safe and highly efficient commercial HTGR power plant as examples of Fuji Electric's recent activities in the HTGR field. (author)

  20. Intelligent Engine Systems: Thermal Management and Advanced Cooling

    Bergholz, Robert

    2008-01-01

    The objective of the Advanced Turbine Cooling and Thermal Management program is to develop intelligent control and distribution methods for turbine cooling, while achieving a reduction in total cooling flow and assuring acceptable turbine component safety and reliability. The program also will develop embedded sensor technologies and cooling system models for real-time engine diagnostics and health management. Both active and passive control strategies will be investigated that include the capability of intelligent modulation of flow quantities, pressures, and temperatures both within the supply system and at the turbine component level. Thermal management system concepts were studied, with a goal of reducing HPT blade cooling air supply temperature. An assessment will be made of the use of this air by the active clearance control system as well. Turbine component cooling designs incorporating advanced, high-effectiveness cooling features, will be evaluated. Turbine cooling flow control concepts will be studied at the cooling system level and the component level. Specific cooling features or sub-elements of an advanced HPT blade cooling design will be downselected for core fabrication and casting demonstrations.

  1. Cool WISPs for stellar cooling excesses

    Giannotti, Maurizio; Irastorza, Igor; Redondo, Javier; Ringwald, Andreas

    2016-05-01

    Several stellar systems (white dwarfs, red giants, horizontal branch stars and possibly the neutron star in the supernova remnant Cassiopeia A) show a mild preference for a non-standard cooling mechanism when compared with theoretical models. This exotic cooling could be provided by Weakly Interacting Slim Particles (WISPs), produced in the hot cores and abandoning the star unimpeded, contributing directly to the energy loss. Taken individually, these excesses do not show a strong statistical weight. However, if one mechanism could consistently explain several of them, the hint could be significant. We analyze the hints in terms of neutrino anomalous magnetic moments, minicharged particles, hidden photons and axion-like particles (ALPs). Among them, the ALP or a massless HP represent the best solution. Interestingly, the hinted ALP parameter space is accessible to the next generation proposed ALP searches, such as ALPS II and IAXO and the massless HP requires a multi TeV energy scale of new physics that might be accessible at the LHC.

  2. Testing Of RSG-GAS Secondary Cooling Component

    The aim of this activity is to improve the mechanical testing technology knowledge of the research reactor cooling pipe material, through a series of testing for the components especially for the mechanical properties of austenitic steel pipe used in RSG-GAS secondary cooling pipe. Scopes of these testing activities are chemical composition analysis, tensile testing, and hardness testing

  3. Stochastic heating of cooling flows

    Pavlovski, Georgi

    2009-01-01

    It is generally accepted that the heating of gas in clusters of galaxies by active galactic nuclei (AGN) is a form of feedback. Feedback is required to ensure a long term, sustainable balance between heating and cooling. This work investigates the impact of proportional stochastic feedback on the energy balance in the intracluster medium. Using a generalised analytical model for a cluster atmosphere, it is shown that an energy equilibrium can be reached exponentially quickly. Applying the tools of stochastic calculus it is demonstrated that the result is robust with regard to the model parameters, even though they affect the amount of variability in the system.

  4. Intelligent Engine Systems: Thermal Management and Advanced Cooling

    Bergholz, Robert

    2008-01-01

    The objective is to provide turbine-cooling technologies to meet Propulsion 21 goals related to engine fuel burn, emissions, safety, and reliability. Specifically, the GE Aviation (GEA) Advanced Turbine Cooling and Thermal Management program seeks to develop advanced cooling and flow distribution methods for HP turbines, while achieving a substantial reduction in total cooling flow and assuring acceptable turbine component safety and reliability. Enhanced cooling techniques, such as fluidic devices, controlled-vortex cooling, and directed impingement jets, offer the opportunity to incorporate both active and passive schemes. Coolant heat transfer enhancement also can be achieved from advanced designs that incorporate multi-disciplinary optimization of external film and internal cooling passage geometry.

  5. Monitoring Cray Cooling Systems

    Maxwell, Don E [ORNL; Ezell, Matthew A [ORNL; Becklehimer, Jeff [Cray, Inc.; Donovan, Matthew J [ORNL; Layton, Christopher C [ORNL

    2014-01-01

    While sites generally have systems in place to monitor the health of Cray computers themselves, often the cooling systems are ignored until a computer failure requires investigation into the source of the failure. The Liebert XDP units used to cool the Cray XE/XK models as well as the Cray proprietary cooling system used for the Cray XC30 models provide data useful for health monitoring. Unfortunately, this valuable information is often available only to custom solutions not accessible by a center-wide monitoring system or is simply ignored entirely. In this paper, methods and tools used to harvest the monitoring data available are discussed, and the implementation needed to integrate the data into a center-wide monitoring system at the Oak Ridge National Laboratory is provided.

  6. Core cooling systems

    The reactor cooling system transports the heat liberated in the reactor core to the component - heat exchanger, steam generator or turbine - where the energy is removed. This basic task can be performed with a variety of coolants circulating in appropriately designed cooling systems. The choice of any one system is governed by principles of economics and natural policies, the design is determined by the laws of nuclear physics, thermal-hydraulics and by the requirement of reliability and public safety. PWR- and BWR- reactors today generate the bulk of nuclear energy. Their primary cooling systems are discussed under the following aspects: 1. General design, nuclear physics constraints, energy transfer, hydraulics, thermodynamics. 2. Design and performance under conditions of steady state and mild transients; control systems. 3. Design and performance under conditions of severe transients and loss of coolant accidents; safety systems. (orig./RW)

  7. Doppler cooling a microsphere

    Barker, P F

    2010-01-01

    Doppler cooling the center-of-mass motion of an optically levitated microsphere via the velocity dependent scattering force from narrow whispering gallery mode (WGM) resonances is described. Light that is red detuned from the WGM resonance can be used to damp the center-of-mass motion in a process analogous to the Doppler cooling of atoms. Leakage of photons out of the microsphere when the incident field is near resonant with the narrow WGM resonance acts to damp the motion of the sphere. The scattering force is not limited by saturation, but can be controlled by the incident power. Cooling times on the order of seconds are calculated for a 20 micron diameter silica microsphere trapped within optical tweezers, with a Doppler temperature limit in the microKelvin regime.

  8. Passive containment cooling system

    Billig, Paul F.; Cooke, Franklin E.; Fitch, James R.

    1994-01-01

    A passive containment cooling system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel and is vented to the drywell. An isolation pool is disposed above the GDCS pool and includes an isolation condenser therein. The condenser has an inlet line disposed in flow communication with the drywell for receiving the non-condensable gas along with any steam released therein following a loss-of-coolant accident (LOCA). The condenser also has an outlet line disposed in flow communication with the drywell for returning to the drywell both liquid condensate produced upon cooling of the steam and the non-condensable gas for reducing pressure within the containment vessel following the LOCA.

  9. Anomalous law of cooling

    Lapas, Luciano C., E-mail: luciano.lapas@unila.edu.br [Universidade Federal da Integração Latino-Americana, Caixa Postal 2067, 85867-970 Foz do Iguaçu, Paraná (Brazil); Ferreira, Rogelma M. S., E-mail: rogelma.maria@gmail.com [Centro de Ciências Exatas e Tecnológicas, Universidade Federal do Recôncavo da Bahia, 44380-000 Cruz das Almas, Bahia (Brazil); Rubí, J. Miguel, E-mail: mrubi@ub.edu [Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Av. Diagonal 647, 08028 Barcelona (Spain); Oliveira, Fernando A., E-mail: fernando.oliveira@pq.cnpq.br [Instituto de Física and Centro Internacional de Física da Matéria Condensada, Universidade de Brasília, Caixa Postal 04513, 70919-970 Brasília, Distrito Federal (Brazil)

    2015-03-14

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  10. Superconductor rotor cooling system

    Gamble, Bruce B.; Sidi-Yekhlef, Ahmed; Schwall, Robert E.; Driscoll, David I.; Shoykhet, Boris A.

    2004-11-02

    A system for cooling a superconductor device includes a cryocooler located in a stationary reference frame and a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with a rotating reference frame in which the superconductor device is located. A method of cooling a superconductor device includes locating a cryocooler in a stationary reference frame, and transferring heat from a superconductor device located in a rotating reference frame to the cryocooler through a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with the rotating reference frame.

  11. Multiphase cooling flows

    Thomas, Peter A.

    1996-01-01

    I discuss the multiphase nature of the intracluster medium whose neglect can lead to overestimates of the baryon fraction of clusters by up to a factor of two. The multiphase form of the cooling flow equations are derived and reduced to a simple form for a wide class of self-similar density distributions. It is shown that steady-state cooling flows are \\emph{not} consistent with all possible emissivity profiles which can therefore be used as a test of the theory. In combination, they provide ...

  12. Anomalous law of cooling

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton’s law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics

  13. Doppler Cooling a Microsphere

    Barker, P F

    2010-01-01

    Doppler cooling the center-of-mass motion of an optically levitated microsphere via the velocity dependent scattering force from narrow whispering gallery mode (WGM) resonances is described. Light that is red detuned from the WGM resonance can be used to damp the center-of-mass motion in a process analogous to the Doppler cooling of atoms. Leakage of photons out of the microsphere when the incident field is near resonant with the narrow WGM resonance acts to damp the motion of the sphere. The...

  14. Anomalous law of cooling

    Lapas, Luciano C.; Ferreira, Rogelma M. S.; Rubí, J. Miguel; Oliveira, Fernando A.

    2015-03-01

    We analyze the temperature relaxation phenomena of systems in contact with a thermal reservoir that undergoes a non-Markovian diffusion process. From a generalized Langevin equation, we show that the temperature is governed by a law of cooling of the Newton's law type in which the relaxation time depends on the velocity autocorrelation and is then characterized by the memory function. The analysis of the temperature decay reveals the existence of an anomalous cooling in which the temperature may oscillate. Despite this anomalous behavior, we show that the variation of entropy remains always positive in accordance with the second law of thermodynamics.

  15. Stochastic cooling for beginners

    These two lectures have been prepared to give a simple introduction to the principles. In Part I we try to explain stochastic cooling using the time-domain picture which starts from the pulse response of the system. In Part II the discussion is repeated, looking more closely at the frequency-domain response. An attempt is made to familiarize the beginners with some of the elementary cooling equations, from the 'single particle case' up to equations which describe the evolution of the particle distribution. (orig.)

  16. Electronic Cooling in Graphene

    Bistritzer, R.; Macdonald, A. H.

    2009-01-01

    Energy transfer to acoustic phonons is the dominant low-temperature cooling channel of electrons in a crystal.For cold neutral graphene we find that the weak cooling power of its acoustical modes relative to the heat capacity of the system leads to a power law decay of the electronic temperature when far from equilibrium. For heavily doped graphene a high electronic temperature is shown to initially decrease linearly with time at a rate proportional to n^(3/2) with n being the electronic dens...

  17. Liquid Cooling/Warming Garment

    Koscheyev, Victor S.; Leon, Gloria R.; Dancisak, Michael J.

    2010-01-01

    The NASA liquid cooling/ventilating garment (LCVG) currently in use was developed over 40 years ago. With the commencement of a greater number of extra-vehicular activity (EVA) procedures with the construction of the International Space Station, problems of astronaut comfort, as well as the reduction of the consumption of energy, became more salient. A shortened liquid cooling/warming garment (SLCWG) has been developed based on physiological principles comparing the efficacy of heat transfer of different body zones; the capability of blood to deliver heat; individual muscle and fat body composition as a basis for individual thermal profiles to customize the zonal sections of the garment; and the development of shunts to minimize or redirect the cooling/warming loop for different environmental conditions, physical activity levels, and emergency situations. The SLCWG has been designed and completed, based on extensive testing in rest, exercise, and antiorthostatic conditions. It is more energy efficient than the LCVG currently used by NASA. The total length of tubing in the SLCWG is approximately 35 percent less and the weight decreased by 20 percent compared to the LCVG. The novel features of the innovation are: 1. The efficiency of the SLCWG to maintain thermal status under extreme changes in body surface temperatures while using significantly less tubing than the LCVG. 2. The construction of the garment based on physiological principles of heat transfer. 3. The identification of the body areas that are most efficient in heat transfer. 4. The inclusion of a hood as part of the garment. 5. The lesser consumption of energy.

  18. Gas-cooled reactors and their applications

    The purpose of the meeting was to review and discuss the current status and recent progress made in the technology and design of gas-cooled reactors and their application for electricity generation, process steam and process heat production. The meeting was attended by more than 200 participants from 25 countries and International Organizations presenting 34 papers. The technical part of the meeting was subdivided into 7 sessions: A. Overview of the Status of Gas-Cooled Reactors and Their Prospects (2 papers); B. Experience with Gas-Cooled Reactors (5 papers); C. Description of Current GCR Plant Designs (10 papers); D. Safety Aspects (4 papers); E. Gas-Cooled Reactor Applications (3 papers); F. Gas-Cooled Reactor Technology (6 papers); G. User's Perspectives on Gas-Cooled Reactors (4 papers). At the end of the meeting a round table discussion was organized in order to summarize the meeting and to make recommendations for future activities. A separate abstract was prepared for each of the 34 presentations of this meeting. Refs, figs and tabs

  19. Cooling tower and environment

    The influence of a cooling tower on the environment, or rather the influence of the environment on the cooling tower stands presently -along with the cooling water supply - in the middle of much discussion. The literature on these questions can hardly be overlooked by the experts concerned, especially not by the power station designers and operators. The document 'Cooling Tower and Environment' is intented to give a general idea of the important publications in this field, and to inform of the present state of technology. In this, the explanations on every section make it easier to get to know the specific subject area. In addition to older standard literature, this publication contains the best-known literature of recent years up to spring 1975, including some articles written in English. Further English literature has been collected by the ZAED (KFK) and is available at the VGB-Geschaefsstelle. Furthermore, The Bundesumweltamt compiles the literature on the subject of 'Environmental protection'. On top of that, further documentation centres are listed at the end of this text. (orig.)

  20. Measure Guideline: Ventilation Cooling

    Springer, D. [Alliance for Residential Building Innovation (ARBI), David, CA (United States); Dakin, B. [Alliance for Residential Building Innovation (ARBI), David, CA (United States); German, A. [Alliance for Residential Building Innovation (ARBI), David, CA (United States)

    2012-04-01

    The purpose of this measure guideline is to provide information on a cost-effective solution for reducing cooling system energy and demand in homes located in hot-dry and cold-dry climates. This guideline provides a prescriptive approach that outlines qualification criteria, selection considerations, and design and installation procedures.

  1. Elementary stochastic cooling

    Major headings in this review include: proton sources; antiproton production; antiproton sources and Liouville, the role of the Debuncher; transverse stochastic cooling, time domain; the accumulator; frequency domain; pickups and kickers; Fokker-Planck equation; calculation of constants in the Fokker-Planck equation; and beam feedback

  2. Physiologic and Functional Responses of MS Patients to Body Cooling Using Commercially Available Cooling Garments

    Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Lee, Hank C.; Luna, Bernadette; Webbon, Bruce W.; Mead, Susan C. (Technical Monitor)

    1999-01-01

    Personal cooling systems are widely used in industrial and aerospace environments to alleviate thermal stress. Increasingly they are also used by heat sensitive multiple sclerosis (HSMS) patients to relieve symptoms and improve quality of life. There are a variety of cooling systems commercially available to the MS community. However, little information is available regarding the comparative physiological changes produced by routine operation of these various systems. The objective of this study was to document and compare the patient response to two passive cooling vests and one active cooling garment. The Life Enhancement Technology, Inc. (LET) lightweight active cooling vest with cap, the MicroClimate Systems (MCS) Change of Phase garment, and the Steele Vest were each used to cool 13 male and 13 female MS subjects (31 to 67 yr.) in this study. The subjects, seated in an upright position at normal room temperature (approximately 22 C), were tested with one of the cooling garments. Oral, fight and left ear temperatures were logged manually every 5 min. An-n, leg, chest and rectal temperatures; heart rate; and respiration were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. Each subject was given a series of subjective and objective evaluation tests before and after cooling. The LET and Steele vests test groups had similar, significant (P less than 0.01) cooling effects on oral and ear canal temperature, which decreased approximately 0.4 C, and 0.3 C, respectively. Core temperature increased (N.S.) with all three vests during cooling. The LET vest produced the coldest (P less than 0.01) skin temperature. Overall, the LET vest provided the most improvement on subjective and objective performance measures. These results show that the garment configurations tested do not elicit a similar thermal response in all MS patients. Cooling with the LET active garment configuration resulted in the lowest body temperatures for the MS subjects; cooling with

  3. ELECTRON COOLING STUDY FOR MEIC

    He, Zhang [Jefferson Lab, Newport News, VA; Douglas, David R. [Jefferson Lab, Newport News, VA; Derbenev, Yaroslav S. [Jefferson Lab, Newport News, VA; Zhang, Yuhong [Jefferson Lab, Newport News, VA

    2015-09-01

    Electron cooling of the ion beams is one critical R&D to achieve high luminosities in JLab's MEIC proposal. In the present MEIC design, a multi-staged cooling scheme is adapted, which includes DC electron cooling in the booster ring and bunched beam electron cooling in the collider ring at both the injection energy and the collision energy. We explored the feasibility of using both magnetized and non-magnetized electron beam for cooling, and concluded that a magnetized electron beam is necessary. Electron cooling simulation results for the newly updated MEIC design is also presented.

  4. Technology of steam generators for gas-cooled reactors. Proceedings of a specialists' meeting

    The activity of the IAEA in the field of the technology of gas-cooled reactors was formalized by formation of an International Working Group on Gas-Cooled Reactors (IWGCR). The gas cooled reactor program considered by the IWGCR includes carbon-dioxide-cooled thermal reactors, helium cooled thermal high temperature reactors for power generation and for process heat applications and gas-cooled fast breeder reactors. This report covers the papers dealing with operating experience, steam generators for next generation of gas-cooled reactors, material development and corrosion problems, and thermohydraulics

  5. STOCHASTIC COOLING FOR BUNCHED BEAMS.

    BLASKIEWICZ, M.

    2005-05-16

    Problems associated with bunched beam stochastic cooling are reviewed. A longitudinal stochastic cooling system for RHIC is under construction and has been partially commissioned. The state of the system and future plans are discussed.

  6. Continuous quantum error correction by cooling

    Sarovar, M; Sarovar, Mohan

    2005-01-01

    We describe an implementation of quantum error correction that operates continuously in time and requires no active interventions such as measurements or gates. The mechanism for carrying away the entropy introduced by errors is a cooling procedure. We evaluate the effectiveness of the scheme by simulation, and remark on the connections between this error correction scheme and the quantum Zeno effect.

  7. Cooling pond temperature prediction

    A model is described which predicts temperature responses in the environment that are associated with the operation of a natural gas fueled thermoelectric power generation station. The model is a piecewise computer simulation, limited at present to closed cooling water systems. However, the techniques developed should be applicable to a much larger class of cooling system. The problem encountered consists of two parts: (1) data characterization and (2) modeling. An efficient characterization scheme for the environmental variables greatly simplifies the task of modeling. Methods borrowed from signal theory, but not yet applied to this field are applicable to and greatly simplify the digital computer investigation of environmental data. An optimal data set, from the point of view of information per unit cost, is described for the model

  8. Water Cooled Mirror Design

    Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Holloway, Michael Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pulliam, Elias Noel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-03-30

    This design is intended to replace the current mirror setup being used for the NorthStar Moly 99 project in order to monitor the target coupon. The existing setup has limited movement for camera alignment and is difficult to align properly. This proposed conceptual design for a water cooled mirror will allow for greater thermal transfer between the mirror and the water block. It will also improve positioning of the mirror by using flexible vacuum hosing and a ball head joint capable of a wide range of motion. Incorporating this design into the target monitoring system will provide more efficient cooling of the mirror which will improve the amount of diffraction caused by the heating of the mirror. The process of aligning the mirror for accurate position will be greatly improved by increasing the range of motion by offering six degrees of freedom.

  9. Magnetic entropy and cooling

    Hansen, Britt Rosendahl; Kuhn, Luise Theil; Bahl, Christian Robert Haffenden

    2010-01-01

    Some manifestations of magnetism are well-known and utilized on an everyday basis, e.g. using a refrigerator magnet for hanging that important note on the refrigerator door. Others are, so far, more exotic, such as cooling by making use of the magnetocaloric eect. This eect can cause a change in...... the temperature of a magnetic material when a magnetic eld is applied or removed. For many years, experimentalists have made use of dilute paramagnetic materials to achieve milliKelvin temperatures by use of the magnetocaloric eect. Also, research is done on materials, which might be used for hydrogen......, helium or nitrogen liquefaction or for room-temperature cooling. The magnetocaloric eect can further be used to determine phase transition boundaries, if a change in the magnetic state occurs at the boundary.In this talk, I will introduce the magnetocaloric eect (MCE) and the two equations, which...

  10. Cool Stars in Hot Places

    Megeath, S. T.; Gaidos, E.; Hester, J. J.; Adams, F. C.; Bally, J.; Lee, J. -E.; Wolk, S.

    2007-01-01

    During the last three decades, evidence has mounted that star and planet formation is not an isolated process, but is influenced by current and previous generations of stars. Although cool stars form in a range of environments, from isolated globules to rich embedded clusters, the influences of other stars on cool star and planet formation may be most significant in embedded clusters, where hundreds to thousands of cool stars form in close proximity to OB stars. At the cool stars 14 meeting, ...

  11. New materials for cooling systems

    New materials based on rubber-vulcanite compounds and used for manufacturing cooling tower elements and coating's of hydraulic structure surfaces are proposed and their production technology is described. A series of studies on physicomechanical and chemical characteristics and hydroaerothermal parameters of cooling tower elements and coatings revealed an obvious advantage of these materials over existing ones. The materials proposed provide high efficiency of cooling tower elements, hydraulic structures and the cooling tower as a whole

  12. Conduction cooled tube supports

    Worley, Arthur C.; Becht, IV, Charles

    1984-01-01

    In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

  13. Low mass integrated cooling

    Mapelli, Alessandro

    2014-01-01

    Low mass on - detec tor cooling systems are being developed and stud ied by the Detector Technology group (PH - DT) in the CERN Physics Department in close collaboration with LHC and non - LHC experiments . Two approaches are currently being investigated. The first approach, for barrel configurations, consists in integrating the cooli ng apparatus in light mechanical structures support ing the detectors. In this case , the thermal management can be achieved either with light cooling pipes and thin plates or with a network of microchannels embedded in thin strips of silicon or polyimide . Both configuratio ns are being investigated in the context of the 2018 upgrade program of the ALICE Inner Tracking System (ITS). Moreover, it is also possible to use a s ilicon microchannel cooling device itself as structural support for the detectors and electronics. Such a configur ation has been adopted by the NA62 collaboration for the ir GigaTracKer (GTK) as well as by the LHCb collaboration for the 2018 major upgrade of...

  14. Electron Cooling of RHIC

    Ben-Zvi, Ilan; Barton, Donald; Beavis, Dana; Blaskiewicz, Michael; Bluem, Hans; Brennan, Joseph M; Bruhwiler, David L; Burger, Al; Burov, Alexey; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Chang, Xiangyun; Cole, Michael; Connolly, Roger; Delayen, Jean R; Derbenev, Yaroslav S; Eidelman, Yury I; Favale, Anthony; Fedotov, Alexei V; Fischer, Wolfram; Funk, L W; Gassner, David M; Hahn, Harald; Harrison, Michael; Hershcovitch, Ady; Holmes, Douglas; Hseuh Hsiao Chaun; Johnson, Peter; Kayran, Dmitry; Kewisch, Jorg; Kneisel, Peter; Koop, Ivan; Lambiase, Robert; Litvinenko, Vladimir N; MacKay, William W; Mahler, George; Malitsky, Nikolay; McIntyre, Gary; Meng, Wuzheng; Merminga, Lia; Meshkov, Igor; Mirabella, Kerry; Montag, Christoph; Nagaitsev, Sergei; Nehring, Thomas; Nicoletti, Tony; Oerter, Brian; Parkhomchuk, Vasily; Parzen, George; Pate, David; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Roser, Thomas; Russo, Thomas; Scaduto, Joseph; Schultheiss, Tom; Sekutowicz, Jacek; Shatunov, Yuri; Sidorin, Anatoly O; Skrinsky, Aleksander Nikolayevich; Smirnov, Alexander V; Smith, Kevin T; Todd, Alan M M; Trbojevic, Dejan; Troubnikov, Grigory; Wang, Gang; Wei, Jie; Williams, Neville; Wu, Kuo-Chen; Yakimenko, Vitaly; Zaltsman, Alex; Zhao, Yongxiang; ain, Animesh K

    2005-01-01

    We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV. A Zeroth Order Design Report is in an advanced draft state, and can be found on the web at http://www.ags...

  15. Conduction cooling: multicrate fastbus hardware

    Described is a new and novel approach for cooling nuclear instrumentation modules via heat conduction. The simplicity of liquid cooled crates and ease of thermal management with conduction cooled modules are described. While this system was developed primarily for the higher power levels expected with Fastbus electronics, it has many general applications

  16. Coolant technology of water cooled reactors. V. 1: Chemistry of primary coolant in water cooled reactors

    This report is a summary of the work performed within the framework of the Coordinated Research Programme on Investigations on Water Chemistry Control and Coolant Interaction with Fuel and Primary Circuit Materials in Water Cooled Power Reactors organized by the IAEA and carried out from 1987 to 1991. It is the continuation of a programme entitled Reactor Water Chemistry Relevant to Coolant-Cladding Interaction (IAEA-TECDOC-429), which ran from 1981 to 1986. Subsequent meetings resulted in the title of the programme being changed to Coolant Technology of Water Cooled Reactors. The results of this Coordinated Research Programme are published in four volumes with an overview in the Technical Reports Series. The titles of the volumes are: Volume 1: Chemistry of Primary Coolant in Water Cooled Reactors; Volume 2: Corrosion in the Primary Coolant Systems of Water Cooled Reactors; Volume 3: Activity Transport Mechanisms in Water Cooled Reactors; Volume 4: Decontamination of Water Cooled Reactors. These publications should be of interest to experts in water chemistry at nuclear power plants, experts in engineering, fuel designers, research and development institutes active in the field and to consultants to these organizations. Refs, figs and tabs

  17. Passive cooling systems in power reactors

    This paper reviews several R and D activities associated with the subject of passive cooling systems, conducted by the N.R.C.Negev thermohydraulic group. A short introduction considering different types of thermosyphons and their applications is followed by a detailed description of the experimental work, its results and conclusions. An ongoing research project is focused on the evaluation of the external dry air passive containment cooling system (PCCS) in the AP-600 (Westinghouse advanced pressurized water reactor). In this context some preliminary theoretical results and planned experimental research are for the fature described

  18. Use of fluorocarbons in the cooling of LHC experiments

    Pimenta dos Santos, M

    2003-01-01

    Perfluorochemicals sold by 3M under the trade name 3M Fluorinert Electronic Liquids have been used for many years as heat transfer media in a variety of industries. The suitability of these liquids for the cooling of LHC experiment originates from their high dielectric strength as well as from their chemical stability under ionizing radiation. The Fluorinerts are clear, colorless, non-flammable with low toxicity and low corrosiveness. Additionally, they offer low global waming potential – GWP – and zero ozone-depletion potential – ODP. Some examples of fluorinert application in the cooling of LHC experiments will be presented : (a) the ATLAS Inner detector C3F8 evaporative cooling system (b) the ATLAS TRF C6F14 monophase cooling system and (c) the ALICE SPD “active heat pipe” C4F10 evaporative cooling system. A brief comparison of evaporative and monophase cooling systems will be outlined.

  19. Cooling lubricants; Kuehlschmierstoffe

    Pfeiffer, W. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Breuer, D. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Blome, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Deininger, C. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Hahn, J.U. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Kleine, H. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Nies, E. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Pflaumbaum, W. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Stockmann, R. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Willert, G. [Berufsgenossenschaftliches Inst. fuer Arbeitssicherheit, St. Augustin (Germany); Sonnenschein, G. [Maschinenbau- und Metall-Berufsgenossenschaft, Duesseldorf (Germany)

    1996-08-01

    As a rule, the base substances used are certain liquid hydrocarbons from mineral oils as well as from native and synthetic oils. Through the addition of further substances the cooling lubricant takes on the particular qualities required for the use in question. Employees working with cooling lubricants are exposed to various hazards. The assessment of the concentrations at the work station is carried out on the basis of existing technical rules for contact with hazardous substances. However, the application/implementation of compulsory investigation and supervision in accordance with these rules is made difficult by the fact that cooling lubricants are, as a rule, made up of complicated compound mixtures. In addition to protecting employees from exposure to mists and vapours from the cooling lubricants, protection for the skin is also of particular importance. Cooling lubricants should not, if at all possible, be brought into contact with the skin. Cleansing the skin and skin care is just as important as changing working clothes regularly, and hygiene and cleanliness at the workplace. Unavoidable emissions are to be immediately collected at the point where they arise or are released and safely disposed of. This means taking into account all sources of emissions. The programme presented in this report therefore gives a very detailed account of the individual protective measures and provides recommendations for the design of technical protection facilities. (orig./MG) [Deutsch] Als Basisstoffe dienen in der Regel bestimmte fluessige Kohlenwasserstoffverbindungen aus Mineraloelen sowie aus nativen oder synthetischen Oelen. Durch die Zugabe von weiteren Stoffen erlangt der Kuehlschmierstoff seine fuer den jeweiligen Anwendungsabfall geforderten Eigenschaften. Beschaeftigte, die mit Kuehlschmierstoffen umgehen, sind unterschiedliche Gefahren ausgesetzt. Die Beurteilung der Kuehlschmierstoffkonzentrationen in der Luft am Arbeitsplatz erfolgt auf der Grundlage bestehender

  20. Black holes, cooling flows and galaxy formation.

    Peacock, J A

    2005-03-15

    Central black holes in galaxies are now well established as a ubiquitous phenomenon, and this fact is important for theories of cosmological structure formation. Merging of galaxy haloes must preserve the proportionality between black hole mass and baryonic mass; the way in which this happens may help solve difficulties with existing ing models of galaxy formation, which suffer from excessive cooling and thus over- produce stars. Feedback from active nuclei may be the missing piece of the puzzle, regulating galaxy-scale cooling flows. Such a process now seems to be observed in cluster-scale cooling flows, where dissipation of sound waves generated by radio lobes can plausibly balance the energy lost in X-rays, at least in a time-averaged sense. PMID:15681292

  1. CFD analysis of evaporation cooling experimental tests

    Falling film evaporation cooling is investigated by a CFD (computational fluid dynamics) code. The experimental activity, carried out at the University of Pisa using the EFFE facility, is aimed to contribute to the understanding of the heat and mass transfer mechanisms involved in cooling of a metallic wall by evaporation of falling water films in a countercurrent air flow. This problem is relevant for innovative nuclear reactor containment. The mathematical model, the governing equations and the boundary conditions implemented in the code are briefly described; a detailed description of the method adopted to account for mass transfer and the presence of the film follows. Then, the calculated results are analysed and compared with experimental data, highlighting the improvement in the cooling capabilities obtained owing to evaporation with respect to the case of pure convection. (authors)

  2. Technological innovations for FBR reactor cooling system

    The fast breeder reactor (FBR) is expected to be commercialized early in the 21st century. In order to realize this goal, technological innovations are desired in order to extensively enhance economic performance, and improvement of the reactor cooling system is of primary importance in this regard. Over the past 10 years, Toshiba has developed a succession of new technologies in the field of reactor cooling systems, including a compact type intermediate heat exchanger (IHX), an integral once-through type steam generator (SG), a double-wall-tube type steam generator, and a sodium-immersed high-temperature type electromagnetic pump (EMP). As a synthesis of the fruits of such research and development we have formulated innovative concepts for a reactor cooling system and its constituent components. These advances in research and development activities will significantly contribute to the commercialization of FBRs. (author)

  3. CFD analysis of evaporation cooling experimental tests

    Ambrosini, W.; Forgione, N.; Mazzini, D.; Oriolo, F. [Pisa Univ., DIMNP (Italy); He, S. [British Energy Generation Ltd, Barnwood Gloucester (United Kingdom)

    2001-07-01

    Falling film evaporation cooling is investigated by a CFD (computational fluid dynamics) code. The experimental activity, carried out at the University of Pisa using the EFFE facility, is aimed to contribute to the understanding of the heat and mass transfer mechanisms involved in cooling of a metallic wall by evaporation of falling water films in a countercurrent air flow. This problem is relevant for innovative nuclear reactor containment. The mathematical model, the governing equations and the boundary conditions implemented in the code are briefly described; a detailed description of the method adopted to account for mass transfer and the presence of the film follows. Then, the calculated results are analysed and compared with experimental data, highlighting the improvement in the cooling capabilities obtained owing to evaporation with respect to the case of pure convection. (authors)

  4. Global Cooling: Policies to Cool the World and Offset Global Warming from CO2 Using Reflective Roofs and Pavements

    Akbari, Hashem; Levinson, Ronnen; Rosenfeld, Arthur; Elliot, Matthew

    2009-08-28

    Increasing the solar reflectance of the urban surface reduce its solar heat gain, lowers its temperatures, and decreases its outflow of thermal infrared radiation into the atmosphere. This process of 'negative radiative forcing' can help counter the effects of global warming. In addition, cool roofs reduce cooling-energy use in air conditioned buildings and increase comfort in unconditioned buildings; and cool roofs and cool pavements mitigate summer urban heat islands, improving outdoor air quality and comfort. Installing cool roofs and cool pavements in cities worldwide is a compelling win-win-win activity that can be undertaken immediately, outside of international negotiations to cap CO{sub 2} emissions. We propose an international campaign to use solar reflective materials when roofs and pavements are built or resurfaced in temperate and tropical regions.

  5. Solar heating cooling. Preparation of possible participation in IEA, Solar Heating Cooling Task 25

    connected to the electric power network and where the effect tax, except in certain German areas, is low. Should a European market for solar cooling be developed a conscious policy is required, which rewards effect savings. Because of the non-existing domestic market and the diffuse European market possibilities active Danish participation in IEA Task 25 it is not recommended. (EHS)

  6. Laser Cooling of Molecular Anions

    Yzombard, Pauline; Gerber, Sebastian; Doser, Michael; Comparat, Daniel

    2015-01-01

    We propose a scheme for laser cooling of negatively charged molecules. We briefly summarise the requirements for such laser cooling and we identify a number of potential candidates. A detailed computation study with C$\\_2^-$, the most studied molecular anion, is carried out. Simulations of 3D laser cooling in a gas phase show that this molecule could be cooled down to below 1 mK in only a few tens of milliseconds, using standard lasers. Sisyphus cooling, where no photo-detachment process is present, as well as Doppler laser cooling of trapped C$\\_2^-$, are also simulated. This cooling scheme has an impact on the study of cold molecules, molecular anions, charged particle sources and antimatter physics.

  7. Water cooled nuclear reactor

    In the reactor operating with supercritical pressure and temperature part of the water flowing through the moderator tubes is deflected at the outlet and mixed with a residual partial flow of the coolant fed into the core as well as passed along the fuel rods in opposite direction. By special guiding of the flow downward through the guide tubes of the control rods insertion of the control rods is simplified because of reduced frictional forces. By this means it is also achieved to design less critical the control rod cooling with respect to flow rate control and operating behavior in case of a scram. (orig.)

  8. Rotary engine cooling system

    Jones, Charles (Inventor); Gigon, Richard M. (Inventor); Blum, Edward J. (Inventor)

    1985-01-01

    A rotary engine has a substantially trochoidal-shaped housing cavity in which a rotor planetates. A cooling system for the engine directs coolant along a single series path consisting of series connected groups of passages. Coolant enters near the intake port, passes downwardly and axially through the cooler regions of the engine, then passes upwardly and axially through the hotter regions. By first flowing through the coolest regions, coolant pressure is reduced, thus reducing the saturation temperature of the coolant and thereby enhancing the nucleate boiling heat transfer mechanism which predominates in the high heat flux region of the engine during high power level operation.

  9. Cooling, AGN Feedback and Star Formation in Simulated Cool-Core Galaxy Clusters

    Li, Yuan; Ruszkowski, Mateusz; Voit, G Mark; O'Shea, Brian W; Donahue, Megan

    2015-01-01

    Numerical simulations of active galactic nuclei (AGN) feedback in cool-core galaxy clusters have successfully avoided classical cooling flows, but often produce too much cold gas. We perform adaptive mesh simulations that include momentum-driven AGN feedback, self-gravity, star formation and stellar feedback, focusing on the interplay between cooling, AGN heating and star formation in an isolated cool-core cluster. Cold clumps triggered by AGN jets and turbulence form filamentary structures tens of kpc long. This cold gas feeds both star formation and the supermassive black hole (SMBH), triggering an AGN outburst that increases the entropy of the ICM and reduces its cooling rate. Within 1-2 Gyr, star formation completely consumes the cold gas, leading to a brief shutoff of the AGN. The ICM quickly cools and redevelops multiphase gas, followed by another cycle of star formation/AGN outburst. Within 6.5 Gyr, we observe three such cycles. There is good agreement between our simulated cluster and the observations...

  10. Cooled spool piston compressor

    Morris, Brian G. (Inventor)

    1993-01-01

    A hydraulically powered gas compressor receives low pressure gas and outputs a high pressure gas. The housing of the compressor defines a cylinder with a center chamber having a cross-sectional area less than the cross-sectional area of a left end chamber and a right end chamber, and a spool-type piston assembly is movable within the cylinder and includes a left end closure, a right end closure, and a center body that are in sealing engagement with the respective cylinder walls as the piston reciprocates. First and second annual compression chambers are provided between the piston enclosures and center housing portion of the compressor, thereby minimizing the spacing between the core gas and a cooled surface of the compressor. Restricted flow passageways are provided in the piston closure members and a path is provided in the central body of the piston assembly, such that hydraulic fluid flows through the piston assembly to cool the piston assembly during its operation. The compressor of the present invention may be easily adapted for a particular application, and is capable of generating high gas pressures while maintaining both the compressed gas and the compressor components within acceptable temperature limits.

  11. ASTROMAG coil cooling study

    Maytal, Ben-Zion; Vansciver, Steven W.

    1990-01-01

    ASTROMAG is a planned particle astrophysics magnetic facility. Basically it is a large magnetic spectrometer outside the Earth's atmosphere for an extended period of time in orbit on a space station. A definition team summarized its scientific objectives assumably related to fundamental questions of astrophysics, cosmology, and elementary particle physics. Since magnetic induction of about 7 Tesla is desired, it is planned to be a superconducting magnet cooled to liquid helium 2 temperatures. The general structure of ASTROMAG is based on: (1) two superconducting magnetic coils, (2) dewar of liquid helium 2 to provide cooling capability for the magnets; (3) instrumentation, matter-anti matter spectrometer (MAS) and cosmic ray isotope spectrometer (CRIS); and (4) interfaces to the shuttle and space station. Many configurations of the superconducting magnets and the dewar were proposed and evaluated, since those are the heart of the ASTROMAG. Baseline of the magnet configuration and cryostat as presented in the phase A study and the one kept in mind while doing the present study are presented. ASTROMAG's development schedule reflects the plan of launching to the space station in 1995.

  12. Cooling Performance of an Impingement Cooling Device Combined with Pins

    Dongliang QUAN; Songling LIU; Jianghai LI; Gaowen LIU

    2005-01-01

    Experimental study and one dimensional model analysis were conducted to investigate cooling performance of an integrated impingement and pin fin cooling device. A typical configuration specimen was made and tested in a large scale low speed closed-looped wind tunnel. Detailed two-dimensional contour maps of the temperature and cooling effectiveness were obtained for different pressure ratios and therefore different coolant flow-rates through the tested specimen. The experimental results showed that very high cooling effectiveness can be achieved by this cooling device with relatively small amount of coolant flow. Based on the theory of transpiration cooling in porous material, a one dimensional heat transfer model was established to analyze the effect of various parameters on cooling effectiveness. It was found from this model that the variation of heat transfer on the gas side, including heat transfer coefficient and film cooling effectiveness, of the specimen created much more effect on its cooling effectiveness than that of the coolant side. The predictions of the one-dimensional mode were compared and agreed well with the experimental data.

  13. A probe for neutron activation analysis in a drill hole using 252Cf, and a Ge(Li) detector cooled by a melting cryogen

    Tanner, A.B.; Moxham, R.M.; Senftle, F.E.; Baicker, J.A.

    1972-01-01

    A sonde has been built for high-resolution measurement of natural or neutron-induced gamma rays in boreholes. The sonde is 7.3 cm in diameter and about 2.2 m in length and weighs about 16 kg. The lithium-compensated germanium semiconductor detector is stabilized at -185 to -188??C for as much as ten hours by a cryostatic reservoir containing melting propane. During periods when the sonde is not in use the propane is kept frozen by a gravity-fed trickle of liquid nitrogen from a reservoir temporarily attached to the cryostat section. A 252Cf source, shielded from the detector, may be placed in the bottom section of the sonde for anlysis by measurement of neutron-activation or neutron-capture gamma rays. Stability of the cryostat with changing hydrostatic pressure, absence of vibration, lack of need for power to the cryostat during operation, and freedom of orientation make the method desirable for borehole, undersea, space, and some laboratory applications. ?? 1972.

  14. Solar heating and cooling technical data and systems analysis

    Christensen, D. L.

    1977-01-01

    The research activities described herein were concentrated on the areas of economics, heating and cooling systems, architectural design, materials characteristics, climatic conditions, educational information packages, and evaluation of solar energy systems and components.

  15. Modelization of cooling system components

    In the site evaluation study for licensing a new nuclear power facility, the criteria involved could be grouped in health and safety, environment, socio-economics, engineering and cost-related. These encompass different aspects such as geology, seismology, cooling system requirements, weather conditions, flooding, population, and so on. The selection of the cooling system is function of different parameters as the gross electrical output, energy consumption, available area for cooling system components, environmental conditions, water consumption, and others. Moreover, in recent years, extreme environmental conditions have been experienced and stringent water availability limits have affected water use permits. Therefore, modifications or alternatives of current cooling system designs and operation are required as well as analyses of the different possibilities of cooling systems to optimize energy production taking into account water consumption among other important variables. There are two basic cooling system configurations: - Once-through or Open-cycle; - Recirculating or Closed-cycle. In a once-through cooling system (or open-cycle), water from an external water sources passes through the steam cycle condenser and is then returned to the source at a higher temperature with some level of contaminants. To minimize the thermal impact to the water source, a cooling tower may be added in a once-through system to allow air cooling of the water (with associated losses on site due to evaporation) prior to returning the water to its source. This system has a high thermal efficiency, and its operating and capital costs are very low. So, from an economical point of view, the open-cycle is preferred to closed-cycle system, especially if there are no water limitations or environmental restrictions. In a recirculating system (or closed-cycle), cooling water exits the condenser, goes through a fixed heat sink, and is then returned to the condenser. This configuration

  16. Stochastic cooling of particle beams

    Moehl, Dieter [European Organization for Nuclear Research (CERN), Geneva (Switzerland)

    2013-02-01

    First topical monograph on this subject matter. Provides conceptual and theoretical introduction. Introduces modern cooling schemes. This lecture note describes the main analytical approaches to stochastic cooling. The first is the time-domain picture, in which the beam is rapidly sampled at a high rate and a statistical analysis is used to describe the cooling behaviour. The second is the frequency-domain picture, which is particularly useful since the observations made on the beam and the numerical cooling simulations are mainly in this domain. This second picture is developed in detail to assess key components of modern cooling theory like mixing and signal shielding and to illustrate some of the diagnostic methods. Finally the use of a distribution function and the Fokker-Plank equation, which offer the most complete description of the beam during the cooling, are discussed.

  17. Transient Performance of Air-cooled Condensing Heat Exchanger in Long-term Passive Cooling System during Decay Heat Load

    In the event of a 'loss of coolant accident'(LOCA) and a non-LOCA, the secondary passive cooling system would be activated to cool the steam in a condensing heat exchanger that is immersed in an emergency cooldown tank (ECT). Currently, the capacities of these ECTs are designed to be sufficient to remove the sensible and residual heat from the reactor coolant system for 72 hours after the occurrence of an accident. After the operation of a conventional passive cooling system for an extended period, however, the water level falls as a result of the evaporation from the ECT, as steam is emitted from the open top of the tank. Therefore, the tank should be refilled regularly from an auxiliary water supply system when the system is used for more than 72 hours. Otherwise, the system would fail to dissipate heat from the condensing heat exchanger due to the loss of the cooling water. Ultimately, the functionality of the passive cooling system would be seriously compromised. As a passive means of overcoming the water depletion in the tank, Kim et al. applied for a Korean patent covering the concept of a long-term passive cooling system for an ECT even after 72 hours. This study presents transient performance of ECT with installing air-cooled condensing heat exchanger under decay heat load. The cooling capacity of an air-cooled condensing heat exchanger was evaluated to determine its practicality

  18. Cooling Torsional Nanomechanical Vibration by Spin-Orbit Interactions

    ZHAO Nan; ZHOU Duan-Lu; ZHU Jia-Lin

    2008-01-01

    We propose and study a spin-orbit interaction based mechanism to actively cool down the torsional vibration of a nanomechanical resonator made by semiconductor materials. We show that the spin-orbit interactions of electrons can induce a coherent coupling between the electron spins and the torsional modes of nanomechanical vibration. This coupling leads to an active cooling for the torsional modes through the dynamical thermalization of the resonator by the spin ensemble.

  19. To Be Cool or Uncool?

    袁会珍

    2007-01-01

    The western world has always been divided into two types of people-the cool and the uncool. It is a division that __1__ in school. The cool kids are good at __2__. They are __3__ with the opposite sex. They are good-looking and people want to __4__ their style. They can do their homework but they don't make a big effort. That would __5__ be cool.

  20. Electron cooling experiments in CSR

    PARKHOMCHUK; Vasily; REVA; Vladimir

    2011-01-01

    The six species heavy ion beam was accumulated with the help of electron cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). The ion beam accumulation dependence on the parameters of cooler was investigated experimentally. The 400 MeV/u 12C6+ and 200 MeV/u 129Xe54+ were stored and cooled in the experimental ring CSRe, and the cooling force was measured in different conditions.

  1. Electron Cooling Experiments in CSR

    Xiaodong, Yang

    2011-01-01

    The six species heavy ion beam was accumulated with the help of electron cooling in the main ring of Cooler Storage Ring of Heavy Ion Research Facility in Lanzhou(HIRFL-CSR), the ion beam accumulation dependence on the parameters of cooler was investigated experimentally. The 400MeV/u 12C6+ and 200MeV/u 129Xe54+ was stored and cooled in the experimental ring CSRe, the cooling force was measured in different condition.

  2. Direct cooled power electronics substrate

    Wiles, Randy H [Powell, TN; Wereszczak, Andrew A [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Lowe, Kirk T [Knoxville, TN

    2010-09-14

    The disclosure describes directly cooling a three-dimensional, direct metallization (DM) layer in a power electronics device. To enable sufficient cooling, coolant flow channels are formed within the ceramic substrate. The direct metallization layer (typically copper) may be bonded to the ceramic substrate, and semiconductor chips (such as IGBT and diodes) may be soldered or sintered onto the direct metallization layer to form a power electronics module. Multiple modules may be attached to cooling headers that provide in-flow and out-flow of coolant through the channels in the ceramic substrate. The modules and cooling header assembly are preferably sized to fit inside the core of a toroidal shaped capacitor.

  3. Cooling of rectangular bars

    A solution of the time-transient Heat Transfer Differential Equation in rectangular coordinates is presented, leading to a model which describes the temperature drop with time in rectangular bars. It is similar to an other model for cilindrical bars which has been previously developed in the Laboratory of Mechanical Metallurgy of UFRGS. Following these models, a generalization has been made, which permits cooling time evaluation for all profiles. These results are compared with experimental laboratory data in the 1200 to 8000C range. Some other existing models were also studied which have the purpose of studing the same phenomenon. Their mathematical forms and their evaluated values are analyzed and compared with experimental ones. (Author)

  4. ATLAS' major cooling project

    2005-01-01

    In 2005, a considerable effort has been put into commissioning the various units of ATLAS' complex cryogenic system. This is in preparation for the imminent cooling of some of the largest components of the detector in their final underground configuration. The liquid helium and nitrogen ATLAS refrigerators in USA 15. Cryogenics plays a vital role in operating massive detectors such as ATLAS. In many ways the liquefied argon, nitrogen and helium are the life-blood of the detector. ATLAS could not function without cryogens that will be constantly pumped via proximity systems to the superconducting magnets and subdetectors. In recent weeks compressors at the surface and underground refrigerators, dewars, pumps, linkages and all manner of other components related to the cryogenic system have been tested and commissioned. Fifty metres underground The helium and nitrogen refrigerators, installed inside the service cavern, are an important part of the ATLAS cryogenic system. Two independent helium refrigerators ...

  5. Fluid cooled electrical assembly

    Rinehart, Lawrence E.; Romero, Guillermo L.

    2007-02-06

    A heat producing, fluid cooled assembly that includes a housing made of liquid-impermeable material, which defines a fluid inlet and a fluid outlet and an opening. Also included is an electrical package having a set of semiconductor electrical devices supported on a substrate and the second major surface is a heat sink adapted to express heat generated from the electrical apparatus and wherein the second major surface defines a rim that is fit to the opening. Further, the housing is constructed so that as fluid travels from the fluid inlet to the fluid outlet it is constrained to flow past the opening thereby placing the fluid in contact with the heat sink.

  6. Film cooling for a closed loop cooled airfoil

    Burdgick, Steven Sebastian; Yu, Yufeng Phillip; Itzel, Gary Michael

    2003-01-01

    Turbine stator vane segments have radially inner and outer walls with vanes extending therebetween. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. At least one film cooling hole is defined through a wall of at least one of the cavities for flow communication between an interior of the cavity and an exterior of the vane. The film cooling hole(s) are defined adjacent a potential low LCF life region, so that cooling medium that bleeds out through the film cooling hole(s) reduces a thermal gradient in a vicinity thereof, thereby the increase the LCF life of that region.

  7. Air cooled absorption chillers for solar cooling applications

    Biermann, W. J.; Reimann, R. C.

    1982-03-01

    The chemical composition of a 'best' absorption refrigerant system is identified, and those properties of the system necessary to design hot water operated, air cooled chilling equipment are determined. Air cooled chillers from single family residential sizes into the commercial rooftop size range are designed and operated.

  8. Cooling Tower Overhaul of Secondary Cooling System in HANARO

    HANARO, an open-tank-in-pool type research reactor of 30 MWth power in Korea, has been operating normally since its initial criticality in February, 1995. For the last about ten years, A cooling tower of a secondary cooling system has been operated normally in HANARO. Last year, the cooling tower has been overhauled for preservative maintenance including fills, eliminators, wood support, water distribution system, motors, driving shafts, gear reducers, basements, blades and etc. This paper describes the results of the overhaul. As results, it is confirmed that the cooling tower maintains a good operability through a filed test. And a cooling capability will be tested when a wet bulb temperature is maintained about 28 .deg. C in summer and the reactor is operated with the full power

  9. Solar hybrid cooling system for high-tech offices in subtropical climate - Radiant cooling by absorption refrigeration and desiccant dehumidification

    Fong, K.F., E-mail: bssquare@cityu.edu.hk [Building Energy and Environmental Technology Research Unit, School of Energy and Environment and Division of Building Science and Technology, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong (China); Chow, T.T.; Lee, C.K.; Lin, Z.; Chan, L.S. [Building Energy and Environmental Technology Research Unit, School of Energy and Environment and Division of Building Science and Technology, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Kowloon, Hong Kong (China)

    2011-08-15

    Highlights: {yields} A solar hybrid cooling system is proposed for high-tech offices in subtropical climate. {yields} An integration of radiant cooling, absorption refrigeration and desiccant dehumidification. {yields} Year-round cooling and energy performances were evaluated through dynamic simulation. {yields} Its annual primary energy consumption was lower than conventional system up to 36.5%. {yields} The passive chilled beams were more energy-efficient than the active chilled beams. - Abstract: A solar hybrid cooling design is proposed for high cooling load demand in hot and humid climate. For the typical building cooling load, the system can handle the zone cooling load (mainly sensible) by radiant cooling with the chilled water from absorption refrigeration, while the ventilation load (largely latent) by desiccant dehumidification. This hybrid system utilizes solar energy for driving the absorption chiller and regenerating the desiccant wheel. Since a high chilled water temperature generated from the absorption chiller is not effective to handle the required latent load, desiccant dehumidification is therefore involved. It is an integration of radiant cooling, absorption refrigeration and desiccant dehumidification, which are powered up by solar energy. In this study, the application potential of the solar hybrid cooling system was evaluated for the high-tech offices in the subtropical climate through dynamic simulation. The high-tech offices are featured with relatively high internal sensible heat gains due to the intensive office electric equipment. The key performance indicators included the solar fraction and the primary energy consumption. Comparative study was also carried out for the solar hybrid cooling system using two common types of chilled ceilings, the passive chilled beams and active chilled beams. It was found that the solar hybrid cooling system was technically feasible for the applications of relatively higher cooling load demand. The annual

  10. Solar hybrid cooling system for high-tech offices in subtropical climate - Radiant cooling by absorption refrigeration and desiccant dehumidification

    Highlights: → A solar hybrid cooling system is proposed for high-tech offices in subtropical climate. → An integration of radiant cooling, absorption refrigeration and desiccant dehumidification. → Year-round cooling and energy performances were evaluated through dynamic simulation. → Its annual primary energy consumption was lower than conventional system up to 36.5%. → The passive chilled beams were more energy-efficient than the active chilled beams. - Abstract: A solar hybrid cooling design is proposed for high cooling load demand in hot and humid climate. For the typical building cooling load, the system can handle the zone cooling load (mainly sensible) by radiant cooling with the chilled water from absorption refrigeration, while the ventilation load (largely latent) by desiccant dehumidification. This hybrid system utilizes solar energy for driving the absorption chiller and regenerating the desiccant wheel. Since a high chilled water temperature generated from the absorption chiller is not effective to handle the required latent load, desiccant dehumidification is therefore involved. It is an integration of radiant cooling, absorption refrigeration and desiccant dehumidification, which are powered up by solar energy. In this study, the application potential of the solar hybrid cooling system was evaluated for the high-tech offices in the subtropical climate through dynamic simulation. The high-tech offices are featured with relatively high internal sensible heat gains due to the intensive office electric equipment. The key performance indicators included the solar fraction and the primary energy consumption. Comparative study was also carried out for the solar hybrid cooling system using two common types of chilled ceilings, the passive chilled beams and active chilled beams. It was found that the solar hybrid cooling system was technically feasible for the applications of relatively higher cooling load demand. The annual primary energy

  11. LS1 Report: Summer cool down

    Katarina Anthony

    2014-01-01

    As the final LS1 activities are carried out in the machine, teams have been cooling down the accelerator sector by sector in preparation for beams.   The third sector of the LHC to be cooled down - sector 1-2 - has seen the process begin this week. During the cool-down phase, survey teams are measuring and smoothing (or realigning) the magnets at cold. By the end of August, five sectors of the machine will be in the process of cooling down, with one (sector 6-7) at cold. The LHC Access Safety System (LASS) is now being commissioned, and will be validated during the DSO tests at the beginning of October. As teams consolidate the modifications made to LASS during the shutdown, many points were closed for testing purposes. The CSCM (copper stabiliser continuity measurement) tests have been completed in the first sector (6-7) and no defect has been found. These results will be presented to the LHC Machine Committee next week. CSCM tests will start in the second sector in mid-August. Following many...

  12. Construction progress of the cooling & ventilation in the LHC project

    Body, Y; Josa, F; Monsted, A; Pirollet, B; CERN. Geneva. ST Division

    2002-01-01

    After the LEP dismantling Phase the Cooling and Ventilation Group has started the LHC construction work. Year 2001 through to 2004 will certainly be the most important period of activity for the CV group in the erection phase The author will report on the current works that are in progress on the different LHC Points distinguishing between the Ventilation and the Water Cooling installations. The Ventilation work completed in the new surface buildings in Points 1, 4,5,6 and 8. The work for the Cooling plants comprehend to the pumping stations, the cooling towers and the chilled water production stations in Points 1 and 5, For all of these activities, an updated report of the progress the work, the planning and of the expenses are given. Finally, a brief overview of the future activities is presented.

  13. Conversion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system

    Vilafranca Manguán, Ana

    2008-01-01

    Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CH...

  14. Newton's Law of Cooling Revisited

    Vollmer, M.

    2009-01-01

    The cooling of objects is often described by a law, attributed to Newton, which states that the temperature difference of a cooling body with respect to the surroundings decreases exponentially with time. Such behaviour has been observed for many laboratory experiments, which led to a wide acceptance of this approach. However, the heat transfer…

  15. Large cooling tower drift deposition

    A model for the determination of drift deposition around natural-draft cooling towers is presented. An application of the model in actual operating conditions indicates the effect of drift rate at the cooling tower outlet and weather conditions on the size and shape of wetted area. (author)

  16. Be Cool, Man! / Jevgeni Levik

    Levik, Jevgeni

    2005-01-01

    Järg 1995. aasta kriminaalkomöödiale "Tooge jupats" ("Get Shorty") : mängufilm "Be Cool, Chili Palmer on tagasi!" ("Be Cool") : režissöör F. Gary Gray, peaosades J. Travolta ja U. Thurman : USA 2005. Lisatud J. Travolta ja U. Thurmani lühiintervjuud

  17. Dialogues in the COOL Project

    Stalpers, S.I.P.; Kroeze, C.

    2013-01-01

    The Climate Options for the Long-term (COOL) Project is a participatory integrated assessment (PIA) comprising extensive dialogues at three levels: national, European and global. The objective of the COOL Project was to ‘develop strategic notions on how to achieve drastic reductions of greenhouse ga

  18. Automotive Cooling and Lubricating Systems.

    Marine Corps Inst., Washington, DC.

    This correspondence course, originally developed for the Marine Corps, is designed to provide new mechanics with a source of study materials to assist them in becoming more proficient in their jobs. The course contains four study units covering automotive cooling system maintenance, cooling system repair, lubricating systems, and lubrication…

  19. Cooling off with physics

    You might think of ice cream as a delicious treat to be enjoyed on a sunny summer's day. However, to the ice-cream scientists who recently gathered in Thessaloniki in Greece for the 2nd International Ice Cream Symposium, it is a complex composite material. Ice cream consists of three dispersed phases: ice crystals, which have a mean size of 50 microns, air bubbles with a diameter of about 70 microns, and fat droplets with a size of 1 micron. These phases are held together by what is called the matrix - not a sci-fi film, but a viscous solution of sugars, milk proteins and polysaccharides. The microstructure, and hence the texture that you experience when you eat ice cream, is created in a freezing process that has remained fundamentally unchanged since the first ice-cream maker was patented in the 1840s. The ingredients - water, milk protein, fat, sugar, emulsifiers, stabilizers, flavours and a lot of air - are mixed together before being pasteurized and homogenized. They are then pumped into a cylinder that is cooled from the outside with a refrigerant. As the mixture touches the cylinder wall it freezes and forms ice crystals, which are quickly scraped off by a rotating blade. The blade is attached to a beater that disperses the ice crystals into the mixture. At the same time, air is injected and broken down into small bubbles by the shear that the beater generates. As the mixture passes along the cylinder, the number of ice crystals increases and its temperature drops. As a result, the viscosity of the mixture increases, so that more energy input is needed to rotate the beater. This energy is dissipated as heat, and when the ice cream reaches about -6 deg. C the energy input through the beater equals the energy removed as heat by the refrigerant. The process therefore becomes self-limiting and it is not possible to cool the ice cream any further. However, at -6 deg. C the microstructure is unstable. The ice cream therefore has to be removed from the freezer and

  20. Actively Cooled Ceramic Composite Nozzle Material Project

    National Aeronautics and Space Administration — For Next Generation Launch Vehicles (NGLV), Either a Rocket-based or Turbine-based Combined Cycle (RBCC or TBCC) engine will power the Next Generation Launch...

  1. Actively Cooled Ceramic Composite Nozzle Material Project

    National Aeronautics and Space Administration — The Phase I Project demonstrated the capability of the Pyrowave? manufacturing process to produce fiber-reinforced ceramics (FRCs) with integral metal features,...

  2. Hydraulic analysis of the Wendelstein 7-X cooling loops

    Smirnow, M., E-mail: michael.smirnow@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Orozco, G.; Boscary, J. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany); Peacock, A. [European Commission c/o Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstr. 2, 85748 Garching (Germany)

    2013-10-15

    Highlights: • A hydraulic simulation model of the W7-X cooling loops and plasma facing components. • CFD analysis of orifice components. • Optimization and flow balancing of cooling loops. -- Abstract: Actively water cooled in vessel components (IVC) are required for the long pulse operation of the stellarator Wendelstein 7-X (W7-X). In total, the cooling pipes have a length of about 4.5 km, supplying the coolant via 304 cooling circuits for the IVC. Within each cooling loop, the IVC are organized mostly in parallel. A homogeneous flow through all branches or at least the minimum specified flow in all of the branches of a circuit is crucial for the IVC to withstand the loading conditions. A detailed hydraulic simulation model of the W7-X cooling loops was built with the commercial code Flowmaster, which is a 1-D computational fluid dynamics software. In order to handle the huge amount of pipe-work data that had to be modelled, a pre- and post-processing macro was developed to transfer the 3D Catia V5 CAD model to the 1-D piping model. Within this model, the hydraulic characteristics of different types of first wall components were simulated, and compared with their pressure drop measurements. As a result of this work, the need for optimization of some cooling loops has been identified and feasible modified solutions were selected.

  3. Hydraulic analysis of the Wendelstein 7-X cooling loops

    Highlights: • A hydraulic simulation model of the W7-X cooling loops and plasma facing components. • CFD analysis of orifice components. • Optimization and flow balancing of cooling loops. -- Abstract: Actively water cooled in vessel components (IVC) are required for the long pulse operation of the stellarator Wendelstein 7-X (W7-X). In total, the cooling pipes have a length of about 4.5 km, supplying the coolant via 304 cooling circuits for the IVC. Within each cooling loop, the IVC are organized mostly in parallel. A homogeneous flow through all branches or at least the minimum specified flow in all of the branches of a circuit is crucial for the IVC to withstand the loading conditions. A detailed hydraulic simulation model of the W7-X cooling loops was built with the commercial code Flowmaster, which is a 1-D computational fluid dynamics software. In order to handle the huge amount of pipe-work data that had to be modelled, a pre- and post-processing macro was developed to transfer the 3D Catia V5 CAD model to the 1-D piping model. Within this model, the hydraulic characteristics of different types of first wall components were simulated, and compared with their pressure drop measurements. As a result of this work, the need for optimization of some cooling loops has been identified and feasible modified solutions were selected

  4. Modelling of flow and heat transfer in PV cooling channels

    Diarra, D.C.; Harrison, S.J. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mechanical and Materials Engineering Solar Calorimetry Lab; Akuffo, F.O. [Kwame Nkrumah Univ. of Science and Technology, Kumasi (Ghana). Dept. of Mechanical Engineering

    2005-07-01

    Under sunny conditions, the temperature of photovoltaic (PV) modules can be 20 to 30 degrees C above the ambient air temperature. This affects the performance of PV modules, particularly in regions with hot climates. For silicon solar cells, the maximum power decreases between 0.4 and 0.5 per cent for every degree C of temperature increase above a reference value. In an effort to address this issue, this experimental and numerical study examined an active PV panel evaporative cooling scheme that is typically used in hot arid climates. The cooling system circulated cool air behind the PV modules, extracting heat and lowering solar cell temperature. A fluid dynamic and thermal model of the combined system was developed using the EES program in order to study the configuration of the cooling channel and the characteristics of the cooling flow. Heat transfer and flow characteristics in the cooling channel were then calculated along with pressure drop and fan power associated with the air-circulation. The net power output was also calculated. The objective was to design a cost efficient cooling system and to optimize its flow and pressure drop in order to maximize power output. The study demonstrated how the performance of the PV panel is influenced by the geometry of the cooling channel, the inlet air temperature and the air flow rate. 2 refs.

  5. Closed loop steam cooled airfoil

    Widrig, Scott M.; Rudolph, Ronald J.; Wagner, Gregg P.

    2006-04-18

    An airfoil, a method of manufacturing an airfoil, and a system for cooling an airfoil is provided. The cooling system can be used with an airfoil located in the first stages of a combustion turbine within a combined cycle power generation plant and involves flowing closed loop steam through a pin array set within an airfoil. The airfoil can comprise a cavity having a cooling chamber bounded by an interior wall and an exterior wall so that steam can enter the cavity, pass through the pin array, and then return to the cavity to thereby cool the airfoil. The method of manufacturing an airfoil can include a type of lost wax investment casting process in which a pin array is cast into an airfoil to form a cooling chamber.

  6. Experiences in solar cooling systems

    Ward, D. S.

    The results of performance evaluations for nine solar cooling systems are presented, and reasons fow low or high net energy balances are discussed. Six of the nine systems are noted to have performed unfavorably compared to standard cooling systems due to thermal storage losses, excessive system electrical demands, inappropriate control strategies, poor system-to-load matching, and poor chiller performance. A reduction in heat losses in one residential unit increased the total system efficiency by 2.5%, while eliminating heat losses to the building interior increased the efficiency by 3.3%. The best system incorporated a lithium bromide absorption chiller and a Rankine cycle compression unit for a commercial application. Improvements in the cooling tower and fan configurations to increase the solar cooling system efficiency are indicated. Best performances are expected to occur in climates inducing high annual cooling loads.

  7. Stochastic cooling of particle beams

    Möhl, Dieter

    2013-01-01

    This lecture note describes the main analytical approaches to stochastic cooling. The first is the time-domain picture, in which the beam is rapidly sampled at a high rate and a statistical analysis is used to describe the cooling behaviour. The second is the frequency-domain picture, which is particularly useful since the observations made on the beam and the numerical cooling simulations are mainly in this domain. This second picture is developed in detail to assess key components of modern cooling theory like mixing and signal shielding and to illustrate some of the diagnostic methods. Finally the use of a distribution function and the Fokker-Plank equation, which offer the most complete description of the beam during the cooling, are discussed.

  8. Interplay among Cooling, AGN Feedback and Anisotropic Conduction in the Cool Cores of Galaxy Clusters

    Yang, H -Y K

    2015-01-01

    Feedback from the active galactic nuclei (AGN) is one of the most promising heating mechanisms to circumvent the cooling-flow problem in galaxy clusters. However, the role of thermal conduction remains unclear. Previous studies have shown that anisotropic thermal conduction in cluster cool cores (CC) could drive the heat-flux driven buoyancy instabilities (HBI) that re-orient the field lines in the azimuthal directions and isolate the cores from conductive heating from the outskirts. However, how the AGN interacts with the HBI is still unknown. To understand these interwined processes, we perform the first 3D magnetohydrodynamic (MHD) simulations of isolated CC clusters that include anisotropic conduction, radiative cooling, and AGN feedback. We find that: (1) For realistic magnetic field strengths in clusters, magnetic tension can suppress a significant portion of HBI-unstable modes and thus the HBI is either completely inhibited or significantly impaired, depending on the unknown magnetic field coherence le...

  9. Film cooling air pocket in a closed loop cooled airfoil

    Yu, Yufeng Phillip; Itzel, Gary Michael; Osgood, Sarah Jane; Bagepalli, Radhakrishna; Webbon, Waylon Willard; Burdgick, Steven Sebastian

    2002-01-01

    Turbine stator vane segments have radially inner and outer walls with vanes extending between them. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. To provide for air film cooing of select portions of the airfoil outer surface, at least one air pocket is defined on a wall of at least one of the cavities. Each air pocket is substantially closed with respect to the cooling medium in the cavity and cooling air pumped to the air pocket flows through outlet apertures in the wall of the airfoil to cool the same.

  10. How to get cool in the heat: comparing analytic models of halo gas cooling with EAGLE

    Stevens, Adam R H; Contreras, Sergio; Croton, Darren J; Padilla, Nelson D; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2016-01-01

    We use the hydrodynamic, cosmological EAGLE simulations to investigate how hot gas in haloes condenses to form and grow galaxies. We select haloes from the simulations that are actively cooling and study the temperature, distribution, and metallicity of their hot, cold, and transitioning `cooling' gas, placing these in context of semi-analytic models. Our selection criteria lead us to focus on Milky Way-like haloes. We find the hot-gas density profiles of the haloes form a progressively stronger core over time, the nature of which can be captured by a beta profile that has a simple dependence on redshift. In contrast, the hot gas that actually cools is broadly consistent with a singular isothermal sphere. We find that cooling gas carries a few times the specific angular momentum of the halo and is offset in spin direction from the rest of the hot gas. The gas loses ~60% of its specific angular momentum during the cooling process, generally remaining greater than that of the halo, and is better aligned with th...

  11. Magnet cooling economics

    The recommendation to use superfluid helium II in superconducting magnet design has become more prevalent in recent years. Advanced fusion reactor studies such as the Mirror Advanced Reactor Study recently completed by the Lawrence Livermore National Laboratory (LLML) have based superconducting magnet design on the use of He II because of reduced magnet volume, improved stability characteristics, or increased superconductor critical current at fields above 9 Tesla. This paper reports the results of a study to determine the capital costs ($/watt) and the operating costs (watts/watt) of refrigeration systems in the 1.8K to 300K temperature range. The cost data is applied to a 1.8K magnet that is subject to neutronic heating wherein the magnet case is insulated from the winding so that the case can be cooled at a higher temperature (less costly) than the winding. The life cycle cost (capital plus operating) is reported as a function of coil temperature and insulation thickness. In some cases there is an optimum, least-cost thickness. In addition, the basic data can be used to evaluate the impact of neutron shielding effectiveness trades on the combined shield, magnet, cryorefrigerator, and operating life cycle cost

  12. Liquid cooled nuclear reactors

    A construction is described for a liquid metal cooled fast reactor, in which the core is supported in a pool of liquid coolant, wherein a catchment tray is provided for any debris falling from the core. The tray comprises a complex of open top collecting vessels with central support struts, the vessels being spaced apart and arranged in layers in a lattice pitch. The lattice pitches of the vessels in each layer are off-set to the lattice pitches of the vessels in the other layers, so that upper vessels partially overlap lower vessels, and the support struts extend through interspaces defined by the vessels in off-set pitch to a common supporting sub-structure. The complex of vessels offers a complete catchment area for falling debris, whilst being pervious to liquid coolant circulating upwardly by convection. The collecting vessels preferably comprise conical dishes and are arranged in triangular lattice pitch in each layer, and the complex of vessels comprises three layers. Alternatively the collecting vessels may be rectilinear and arranged on a square lattice. The catchment tray may comprise two or more such complexes in stacked array. (U.K.)

  13. Central cooling: absorptive chillers

    Christian, J.E.

    1977-08-01

    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  14. 46 CFR 153.432 - Cooling systems.

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cooling systems. 153.432 Section 153.432 Shipping COAST... Control Systems § 153.432 Cooling systems. (a) Each cargo cooling system must have an equivalent standby... cooling system. (b) Each tankship that has a cargo tank with a required cooling system must have a...

  15. A model for radionuclide transport in the Cooling Water System

    A radionuclide transport model developed to assess radiological levels in the K-reactor Cooling Water System (CWS) in the event of an inadvertent process water (PW) leakage to the cooling water (CW) in the heat exchangers (HX) is described. During and following a process water leak, the radionuclide transport model determines the time-dependent release rates of radionuclide from the cooling water system to the environment via evaporation to the atmosphere and blow-down to the Savannah River. The developed model allows for delay times associated with the transport of the cooling water radioactivity through cooling water system components. Additionally, this model simulates the time-dependent behavior of radionuclides levels in various CWS components. The developed model is incorporated into the K-reactor Cooling Tower Activity (KCTA) code. KCTA allows the accident (heat exchanger leak rate) and the cooling tower blow-down and evaporation rates to be described as time-dependent functions. Thus, the postulated leak and the consequence of the assumed leak can be modelled realistically. This model is the first of three models to be ultimately assembled to form a comprehensive Liquid Pathway Activity System (LPAS). LPAS will offer integrated formation, transport, deposition, and release estimates for radionuclides formed in a SRS facility. Process water and river water modules are forthcoming as input and downstream components, respectively, for KCTA

  16. Preliminary design package for prototype solar heating and cooling systems

    1978-01-01

    A summary is given of the preliminary analysis and design activity on solar heating and cooling systems. The analysis was made without site specific data other than weather; therefore, the results indicate performance expected under these special conditions. Major items include a market analysis, design approaches, trade studies and other special data required to evaluate the preliminary analysis and design. The program calls for the development and delivery of eight prototype solar heating and cooling systems for installation and operational test. Two heating and six heating and cooling units will be delivered for Single Family Residences, Multiple-family Residences and commercial applications.

  17. High conductivity Be-Cu alloys for fusion reactors

    Lilley, E.A. [NGK Metals Corp., Reading, PA (United States); Adachi, Takao; Ishibashi, Yoshiki [NGK Insulators, Ltd., Aichi-ken (Japan)

    1995-09-01

    The optimum material has not yet been identified. This will result in heat from plasma to the first wall and divertor. That is, because of cracks and melting by thermal power and shock. Today, it is considered to be some kinds of copper, alloys, however, for using, it must have high conductivity. And it is also needed another property, for example, high strength and so on. We have developed some new beryllium copper alloys with high conductivity, high strength, and high endurance. Therefore, we are introducing these new alloys as suitable materials for the heat sink in fusion reactors.

  18. The Cool 100 book

    Haselip, J.; Pointing, D.

    2011-07-01

    The aim of The Cool 100 book is to document 100 inspiring, educational and practical examples of sustainable and accessible energy supply solutions created by, or suitable for, isolated communities in the cooler regions of the world. The book features the following projects, explored in detail: 1. Promoting Unst Renewable Energy (PURE) project, a pioneering project that demonstrates how wind power and hydrogen technologies can be combined to meet the energy needs of a remote industrial estate on the island of Unst in the British Isles. 2. The EDISON project, or Electric vehicles in a Distributed and Integrated market using Sustainable energy and Open Networks that explored increased renewable energy use and electric vehicle operation in Denmark, with a case study on the island of Bornholm. 3. The Sarfannguit Wireless Electricity Reading project, which has significantly improved utility metering and enabled improved energy management, reduced electricity demand, and the introduction of renewable energy technologies in the isolated villages of Greenland. 4. The Renewable Energy Croft and Hydrogen facility, which uses innovative technologies to support a gardening facility in the Outer Hebrides (Scotland), and is also a working laboratory for students of the local university to develop a hydrogen energy economy. 5. The Samsoe Renewable Energy Island in Denmark, an iconic example of how an island community can consume only green electricity by using a range of innovative technologies and behavioural changes to reduce demand and to harness green energy resources. 6. The Hydrogen Office Project which demonstrates how a commercial office in the coastal town of Methil in Scotland can be supported by a novel renewable, hydrogen and fuel cell energy system, and how the local community is engaged with the project. 7. The Northern Sustainable House in Nunavut, Canada, which explores the process and results of a project to design and implement housing for local families that

  19. Novel cooling strategy for electronic packages: Directly injected cooling

    Wits, W.W.; Vaneker, T.H.J.; Mannak, J.H.; Legtenberg, R.

    2009-01-01

    This publication describes the development of a novel cooling strategy for electronic packages. During the conceptual design phase, the engineering disciplines involved are considered simultaneously. Through a case study, it is demonstrated that this integrative approach is an effective methodology

  20. Lithium-cooled blankets for advanced tokamaks

    The main objective of the Tokamak Power System Studies (TPSS) at Argonne National Lab. during fiscal year 1985 was to explore innovative design concepts that have the potential for significant enhancement of the attractiveness of a tokamak-based power plant. Activities in the area of plasma engineering resulted in a reference reactor concept, which served as a model for the impurity control and first-wall/blanket/shield studies. The liquid-metal-cooled first-wall/blanket/shield design activity was centered around the vanadium alloy structure and liquid-lithium coolant leading blanket concept as identified by the Blanket Comparison and Selection Study (BCSS). A ferritic steel structure and a LiPb breeder were considered as backup options. The magnetohydrodynamics (MHD) effects associated with self-cooled liquid-metal blanket/first-wall systems are substantially reduced by the lower magnetic fields required for higher plasmas, the lower neutron wall loading resulting from reduced power output, and the smaller reactor size of the TPSS model reactor. Therefore, improved performance characteristics of self-cooled liquid-metal blanket concepts are achievable mainly because the design constraints are more relaxed compared to the BCSS guidelines. Key aspects of the designs evaluated in the current study include the following: (1) design simplicity; (2) use of the first wall as an impurity control device; (3) modular first-wall/blanket/reflector/shield construction; and (4) integrated first-wall/blanket/reflector/shield

  1. European supercritical water cooled reactor

    Highlights: → The HPLWR reactor design is an example of a supercritical water cooled reactor. → Cladding material tests have started but materials are not yet satisfactory. → Numerical heat transfer predictions are promising but need further validation. → The research project is most suited for nuclear education and training. - Abstract: The High Performance Light Water Reactor (HPLWR), how the European Supercritical Water Cooled Reactor is called, is a pressure vessel type reactor operated with supercritical water at 25 MPa feedwater pressure and 500 oC average core outlet temperature. It is designed and analyzed by a European consortium of 10 partners and 3 active supporters from 8 Euratom member states in the second phase of the HPLWR project. Most emphasis has been laid on a core with a thermal neutron spectrum, consisting of small fuel assemblies in boxes with 40 fuel pins each and a central water box to improve the neutron moderation despite the low coolant density. Peak cladding temperatures of the fuel rods have been minimized by heating up the coolant in three steps with intermediate coolant mixing. The containment design with its safety and residual heat removal systems is based on the latest boiling water reactor concept, but with different passive high pressure coolant injection systems to cause a forced convection through the core. The design concept of the steam cycle is indicating the envisaged efficiency increase to around 44%. Moreover, it provides the constraints to design the components of the balance of the plant. The project is accompanied by numerical studies of heat transfer of supercritical water in fuel assemblies and by material tests of candidate cladding alloys, performed by the consortium and supported by additional tests of the Joint Research Centre of the European Commission. Besides the scientific and technical progress, the HPLWR project turned out to be most successful in training the young generation of nuclear engineers

  2. Mini-Membrane Evaporator for Contingency Spacesuit Cooling

    Makinen, Janice V.; Bue, Grant C.; Campbell, Colin; Petty, Brian; Craft, Jesse; Lynch, William; Wilkes, Robert; Vogel, Matthew

    2015-01-01

    The next-generation Advanced Extravehicular Mobility Unit (AEMU) Portable Life Support System (PLSS) is integrating a number of new technologies to improve reliability and functionality. One of these improvements is the development of the Auxiliary Cooling Loop (ACL) for contingency crewmember cooling. The ACL is a completely redundant, independent cooling system that consists of a small evaporative cooler--the Mini Membrane Evaporator (Mini-ME), independent pump, independent feedwater assembly and independent Liquid Cooling Garment (LCG). The Mini-ME utilizes the same hollow fiber technology featured in the full-sized AEMU PLSS cooling device, the Spacesuit Water Membrane Evaporator (SWME), but Mini-ME occupies only approximately 25% of the volume of SWME, thereby providing only the necessary crewmember cooling in a contingency situation. The ACL provides a number of benefits when compared with the current EMU PLSS contingency cooling technology, which relies upon a Secondary Oxygen Vessel; contingency crewmember cooling can be provided for a longer period of time, more contingency situations can be accounted for, no reliance on a Secondary Oxygen Vessel (SOV) for contingency cooling--thereby allowing a reduction in SOV size and pressure, and the ACL can be recharged-allowing the AEMU PLSS to be reused, even after a contingency event. The first iteration of Mini-ME was developed and tested in-house. Mini-ME is currently packaged in AEMU PLSS 2.0, where it is being tested in environments and situations that are representative of potential future Extravehicular Activities (EVA's). The second iteration of Mini-ME, known as Mini-ME2, is currently being developed to offer more heat rejection capability. The development of this contingency evaporative cooling system will contribute to a more robust and comprehensive AEMU PLSS.

  3. The Cooling of Compact Stars

    Page, D; Weber, F; Page, Dany; Geppert, Ulrich; Weber, Fridolin

    2005-01-01

    The cooling of a compact star depends very sensitively on the state of dense matter at supranuclear densities, which essentially controls the neutrino emission, as well as on the structure of the stellar outer layers which control the photon emission. Open issues concern the hyperon population, the presence of meson condensates, superfluidity and superconductivity, and the transition of confined hadronic matter to quark matter. This paper describes these issues and presents cooling calculations based on a broad collection of equations of state for neutron star matter and strange matter. These results are tested against the body of observed cooling data.

  4. New Approaches to Final Cooling

    Neuffer, David

    2015-01-01

    A high-energy muon collider scenario requires a "final cooling" system that reduces transverse emittance by a factor of ~10 while allowing longitudinal emittance increase. The baseline approach has low-energy transverse cooling within high-field solenoids, with strong longitudinal heating. This approach and its recent simulation are discussed. Alternative approaches which more explicitly include emittance exchange are also presented. Round-to-flat beam transform, transverse slicing, and longitudinal bunch coalescence are possible components of the alternative approach. A more explicit understanding of solenoidal cooling beam dynamics is introduced.

  5. Stochastic cooling of bunched beams

    Numerical simulation studies are presented for transverse and longitudinal stochastic cooling of bunched particle beams. Radio frequency buckets of various shapes (e.g. rectangular, parabolic well, single sinusoidal waveform) are used to investigate the enhancement of phase space cooling by nonlinearities of synchrotron motion. The connection between the notions of Landau damping for instabilities and mixing for stochastic cooling are discussed. In particular, the need for synchrotron frequency spread for both Landau damping and good mixing is seen to be comparable for bunched beams

  6. CO$_2$ cooling experience (LHCb)

    Van Lysebetten, Ann; Verlaat, Bart

    2007-01-01

    The thermal control system of the LHCb VErtex LOcator (VELO) is a two-phase C0$_2$ cooling system based on the 2-Phase Accumulator Controlled Loop (2PACL) method. Liquid carbon dioxide is mechanically pumped in a closed loop, chilled by a water-cooled freon chiller and evaporated in the VELO detector. The main goal of the system is the permanent cooling of the VELO silicon sensors and of the heat producing front-end electronics inside a vacuum environment. This paper describes the design and the performance of the system. First results obtained during commissioning are also presented.

  7. Cooling towers principles and practice

    Hill, G B; Osborn, Peter D

    2013-01-01

    Cooling Towers: Principles and Practice, Third Edition, aims to provide the reader with a better understanding of the theory and practice, so that installations are correctly designed and operated. As with all branches of engineering, new technology calls for a level of technical knowledge which becomes progressively higher; this new edition seeks to ensure that the principles and practice of cooling towers are set against a background of up-to-date technology. The book is organized into three sections. Section A on cooling tower practice covers topics such as the design and operation of c

  8. Helium-cooling in fusion power plants

    This paper reviews different helium-cooled first wall and blanket designs; and compares the selection of structural materials. The authors found that the solid breeder, SiC-composite material option generates the lowest amount of induced radioactivity and afterheat and has the highest temperature capability. When combined with the direct cycle gas turbine system, it has the potential to be the most economical fusion system and can compete with advanced fission reactors. When compared to martensitic steel and V-alloy, SiC-composite is the least developed of these three structural materials, a focused development effort will be needed. Fundamental research has begun in addressing the issues of optimized composite materials, irradiation effects, leak tightness and low activation braze materials. Development of helium-cooled high heat flux components and further development of the direct cycle gas turbine system will also be needed

  9. Cooling flows around radio-loud QSO

    Long-slit spectroscopy is presented for a sample of 31 QSO and radio galaxies, mostly selected on the basis of their X-ray and radio properties, in order to investigate any similarity of their surrounding nebulosity to emission-line gas around cooling flow galaxies at lower redshift. Nine objects (five QSO) show extended oxygen emission. For eight of these, a measurement or limit of the ratio of the redshifted [O III]λ5007/[O II]λ3727 emission lines in the nebulosity is made, after removal of any spillover light from the nucleus. The ratio is compared with that expected from gas at the observed radius photoionized by the active nucleus in order to determine the density, and hence pressure, of the gas. The sample is extended by including observations of similar objects from other work. Of the extended objects modelled, seven are consistent with the cooling flow hypothesis. (author)

  10. Prototype solar heating and cooling systems, including potable hot water

    Bloomquist, D.; Oonk, R. L.

    1977-01-01

    Progress made in the development, delivery, and support of two prototype solar heating and cooling systems including potable hot water is reported. The system consists of the following subsystems: collector, auxiliary heating, potable hot water, storage, control, transport, and government-furnished site data acquisition. A comparison of the proposed Solaron Heat Pump and Solar Desiccant Heating and Cooling Systems, installation drawings, data on the Akron House at Akron, Ohio, and other program activities are included.

  11. Operational Characteristics of Four Commercially Available Personal Cooling Vests

    Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Lee, Hank C.; Webbon, Bruce W.; Kliss, Mark (Technical Monitor)

    1997-01-01

    Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive and two active cooling vests, and to measure the body temperature and circulatory changes produced by each cooling vest configuration. The MicroClimate Systems and the Life Enhancement Tech(LET) lightweight liquid cooling vests, the Steele Vest and LET's Zipper Front Garment were used to cool the chest region of 11 male and 10 female subjects (25 to 55 yr.) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approx.21 C), were tested for 60 min. with the cooling system operated at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a URI Inc. Biolog ambulatory monitor. In general, the male and female subjects' rectal and ear temperature responses to cooling were similar for all vest configurations tested. Oral temperatures during the recovery period were significantly (Pcooling and recovery periods. These results show that all vest configurations elicit a similar thermal response in both male and female subject groups. However, subject population variance was rather large and may have masked differences between the vests. One vest may prove more effective than another for a given individual, and experience is the only means of determining this.

  12. Passive low energy cooling of buildings

    Givoni, Baruch

    1994-01-01

    A practical sourcebook for building designers, providing comprehensive discussion of the impact of basic architectural choices on cooling efficiency, including the layout and orientation of the structure, window size and shading, exterior color, and even the use of plantings around the site. All major varieties of passive cooling systems are presented, with extensive analysis of performance in different types of buildings and in different climates: ventilation; radiant cooling; evaporative cooling; soil cooling; and cooling of outdoor spaces.

  13. Solar heating cooling. Preparation of possible participation in IEA, Solar Heating Cooling Task 25; Solvarmedrevet koeling. Forberedelse af evt. deltagelse i IEA, Solar Heating Cooling Task 25

    NONE

    2001-03-01

    everybody are connected to the electric power network and where the effect tax, except in certain German areas, is low. Should a European market for solar cooling be developed a conscious policy is required, which rewards effect savings. Because of the non-existing domestic market and the diffuse European market possibilities active Danish participation in IEA Task 25 it is not recommended. (EHS)

  14. Cooled Ceramic Turbine Vane Project

    National Aeronautics and Space Administration — N&R Engineering will investigate the feasibility of cooled ceramics, such as ceramic matrix composite (CMC) turbine blade concepts that can decrease specific...

  15. Surface-induced evaporative cooling

    Ke Min; Yan Bo; Cheng Feng; Wang Yu-Zhu

    2009-01-01

    The effects of surface-induced evaporative cooling on an atom chip are investigated. The evolutions of temperature, number and phase-space density of the atom cloud are measured when the atom cloud is brought close to the surface. Rapid decrease of the temperature and number of the atoms is found when the atom-surface distance is < 100 μm. A gain of about a factor of five on the phase-space density is obtained. It is found that the efficiency of the surface-induced evaporative cooling depends on the atom-surface distance and the shape of the evaporative trap. When the atoms are moved very close to the surface, severe heating is observed, which dominates when the holding time is > 8 ms. It is important that the surface-induced evaporative cooling offers novel possibilities for the realization of a continuous condensation, where a spatially varying evaporative cooling is required.

  16. Advance in MEIC cooling studies

    Zhang, Yuhong [JLAB, Newport News, VA (United States); Derbenev, Ya. [JLAB, Newport News, VA (United States); Douglas, D. [JLAB, Newport News, VA (United States); Hutton, A. [JLAB, Newport News, VA (United States); Kimber, A. [JLAB, Newport News, VA (United States); Li, R. [JLAB, Newport News, VA (United States); Nissen, E. [JLAB, Newport News, VA (United States); Tennant, [JLAB, Newport News, VA (United States); Zhang, H. [JLAB, Newport News, VA (United States)

    2013-06-01

    Cooling of ion beams is essential for achieving a high luminosity for MEIC at Jefferson Lab. In this paper, we present the design concept of the electron cooling system for MEIC. In the design, two facilities are required for supporting a multi-staged cooling scheme; one is a 2 MeV DC cooler in the ion pre-booster; the other is a high electron energy (up to 55 MeV) ERL-circulator cooler in the collider ring. The simulation studies of beam dynamics in an ERL-circulator cooler are summarized and followed by a report on technology development for this cooler. We also discuss two proposed experiments for demonstrating high energy cooling with a bunched electron beam and the ERL-circulator cooler.

  17. Cooled water rod (loca conditions)

    A process is described for providing a radiation heat sink for fuel bundles having a large water moderator tube in the event of a loss of coolant accident the fuel bundles having an upper tie plate, a lower tie plate, a channel surrounding and connecting the tie plate, a plurality of fuel rods supported between the tie plates and within the channels in side by side upstanding relation; a large water moderator tube having at least twice the diameter of the fuel rods. The process consists of: spraying core cooling spray in an evenly divided flow over the upper tie plate; collecting core cooling spray at an uper end of the large water moderator tube; and distributing the core cooling spray circumferentially along the inner surfaces of the large water moderator tube in a downward flow separating the flow of the core cooling spray from the flow of steam resulting from the flashing of water to steam within the moderator tube

  18. Acoustical Convective Cooling Or Heating

    Trinh, Eugene H.; Robey, Judith L.

    1988-01-01

    Small, efficient ultrasonic device circulates fluid. Vibrating at ultrasonic frequency, piezoelectric driver sets up vortexes transfering heat to or from object in space. Used on Earth to apply localized or concentrated cooling to individual electronic components or other small parts.

  19. Geothermal heat can cool, too

    This article takes a look at how geothermal energy can not only be used to supply heating energy, but also be used to provide cooling too. The article reports on a conference on heating and cooling with geothermal energy that was held in Duebendorf, Switzerland, in March 2008. The influence of climate change on needs for heating and cooling and the need for additional knowledge and data on deeper rock layers is noted. The seasonal use of geothermal systems to provide heating in winter and cooling in summer is discussed. The planning of geothermal probe fields and their simulation is addressed. As an example, the geothermal installations under the recently renewed and extended 'Dolder Grand' luxury hotel in Zurich are quoted. The new SIA 384/6 norm on geothermal probes issued by the Swiss Association of Architects SIA is briefly reviewed.

  20. Compressor bleed cooling fluid feed system

    Donahoo, Eric E; Ross, Christopher W

    2014-11-25

    A compressor bleed cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor to a turbine airfoil cooling system to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The compressor bleed cooling fluid feed system may enable cooling fluids to be exhausted from a compressor exhaust plenum through a downstream compressor bleed collection chamber and into the turbine airfoil cooling system. As such, the suction created in the compressor exhaust plenum mitigates boundary layer growth along the inner surface while providing flow of cooling fluids to the turbine airfoils.

  1. Oil cooled, hermetic refrigerant compressor

    English, William A.; Young, Robert R.

    1985-01-01

    A hermetic refrigerant compressor having an electric motor and compressor assembly in a hermetic shell is cooled by oil which is first cooled in an external cooler 18 and is then delivered through the shell to the top of the motor rotor 24 where most of it is flung radially outwardly within the confined space provided by the cap 50 which channels the flow of most of the oil around the top of the stator 26 and then out to a multiplicity of holes 52 to flow down to the sump and provide further cooling of the motor and compressor. Part of the oil descends internally of the motor to the annular chamber 58 to provide oil cooling of the lower part of the motor, with this oil exiting through vent hole 62 also to the sump. Suction gas with entrained oil and liquid refrigerant therein is delivered to an oil separator 68 from which the suction gas passes by a confined path in pipe 66 to the suction plenum 64 and the separated oil drops from the separator to the sump. By providing the oil cooling of the parts, the suction gas is not used for cooling purposes and accordingly increase in superheat is substantially avoided in the passage of the suction gas through the shell to the suction plenum 64.

  2. Cooling of concrete structure in advanced heavy water reactor

    Innovative nuclear power plants are being designed by incorporation of passive systems to the extent possible for enhancing the safety by elimination of active components. BARC has designed Advanced Heavy Water Reactor (AHWR) incorporating several passive systems to facilitate the fulfillment of safety functions of the reactor during normal operation, residual heat removal, emergency core cooling, confinement of radioactivity etc. In addition to these passive systems, an innovative passive technology is being developed to protect, the concrete structure in high temperature zone (V1-volume). Passive Concrete Cooling System (PConCS) uses the principle of natural circulation to provide cooling outside the insulation cabinet encompassing high temperature piping. Cooling water is circulated from overhead GDWP in cooling pipes fixed over corrugated plate on outer surface of insulation cabinet and maintains low temperature of concrete structure. Modular construction of insulation cabinet and cooling pipes external to the concrete surface simplifies the design, construction and refurbishment if required. The paper describes the details of passive technology for concrete cooling. (author)

  3. Cooling Rate Determination in Additively Manufactured Aluminum Alloy 2219

    Brice, Craig A.; Dennis, Noah

    2015-05-01

    Metallic additive manufacturing processes generally utilize a conduction mode, welding-type approach to create beads of deposited material that can be arranged into a three-dimensional structure. As with welding, the cooling rates in the molten pool are relatively rapid compared to traditional casting techniques. Determination of the cooling rate in the molten pool is critical for predicting the solidified microstructure and resultant properties. In this experiment, wire-fed electron beam additive manufacturing was used to melt aluminum alloy 2219 under different thermal boundary conditions. The dendrite arm spacing was measured in the remelted material, and this information was used to estimate cooling rates in the molten pool based on established empirical relationships. The results showed that the thermal boundary conditions have a significant effect on the resulting cooling rate in the molten pool. When thermal conduction is limited due to a small thermal sink, the dendrite arm spacing varies between 15 and 35 µm. When thermal conduction is active, the dendrite arm spacing varies between 6 and 12 µm. This range of dendrite arm spacing implies cooling rates ranging from 5 to 350 K/s. Cooling rates can vary greatly as thermal conditions change during deposition. A cooling rate at the higher end of the range could lead to significant deviation from microstructural equilibrium during solidification.

  4. Microtextured Surfaces for Turbine Blade Impingement Cooling

    Fryer, Jack

    2014-01-01

    Gas turbine engine technology is constantly challenged to operate at higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can exceed the blade and disk material limits by 600 F or more, necessitating both internal and film cooling schemes in addition to the use of thermal barrier coatings. Internal convective cooling is inadequate in many blade locations, and both internal and film cooling approaches can lead to significant performance penalties in the engine. Micro Cooling Concepts, Inc., has developed a turbine blade cooling concept that provides enhanced internal impingement cooling effectiveness via the use of microstructured impingement surfaces. These surfaces significantly increase the cooling capability of the impinging flow, as compared to a conventional untextured surface. This approach can be combined with microchannel cooling and external film cooling to tailor the cooling capability per the external heating profile. The cooling system then can be optimized to minimize impact on engine performance.

  5. Biomedical Use of Aerospace Personal Cooling Garments

    Webbon, Bruce W.; Montgomery, Leslie D.; Callaway, Robert K.

    1994-01-01

    Personal thermoregulatory systems are required during extravehicular activity (EVA) to remove the metabolic heat generated by the suited astronaut. The Extravehicular and Protective Systems (STE) Branch of NASA Ames Research Center has developed advanced concepts or liquid cooling garments for both industrial and biomedical applications for the past 25 years. Examples of this work include: (1) liquid cooled helmets for helicopter pilots and race car drivers; (2) vests for fire and mine rescue personnel; (3) bras to increase the definition of tumors during thermography; (4) lower body garments for young women with erythomelaigia; and (5) whole body garments used by patients with multiple sclerosis (MS). The benefits of the biomedical application of artificial thermoregulation received national attention through two recent events: (1) the liquid-cooled garment technology was inducted into the United States Space Foundation's Space Technology Hall of Fame (1993); and (2) NASA has signed a joint Memorandum of Understanding with the Multiple Sclerosis Association (1994) to share this technology for use with MS patient treatment. The STE Branch is currently pursuing a program to refine thermoregulatory design in light of recent technology developments that might be applicable for use by several medical patient populations. Projects have been initiated to apply thermoregulatory technology for the treatment and/or rehabilitation of patients with spinal cord injuries, multiple sclerosis, migraine headaches, and to help prevent the loss of hair during chemotherapy.

  6. Personal cooling systems: Possibilities and limitations

    Nunneley, Sarah A.

    1994-01-01

    Personal thermal control by means of gas- or liquid-conditioned garments was developed during the 1960s and has been applied in a variety of aerospace and industrial settings. Both USAF fighter pilots and astronauts are required to wear heavy protective clothing which insulates them from the environment and thus creates stress through storage of metabolic heat. The problem is particularly severe in astronauts who perform heavy physical work during extra-vehicular activity (EVA); without artificial cooling they could reach incapacitating hyperthermia in a matter of minutes. This paper reviews the factors which influence the design of personal cooling systems. An important early step is determination of acceptable heat stress level, taking into account possible interactions of heat stress with other physiological problems such as motion sickness, diminished plasma volume, decompression sickness and acceleration tolerance. Other factors which require consideration include the work schedule, the area to be covered by the cooling garment, and the practicalities of a fixed or body-mounted heat sink and its power source. Nearly every imaginable heat sink has been proposed or tried over the past 30 years, including direct gas systems, phase-change systems with open or closed loops and thermoelectric heat sinks. The latter are now the system of choice for aircraft.

  7. The Stability of Radiatively Cooling Jets I. Linear Analysis

    Hardee, Philip E.; Stone, James M.

    1997-01-01

    The results of a spatial stability analysis of a two-dimensional slab jet, in which optically thin radiative cooling is dynamically important, are presented. We study both magnetized and unmagnetized jets at external Mach numbers of 5 and 20. We model the cooling rate by using two different cooling curves: one appropriate to interstellar gas, and the other to photoionized gas of reduced metallicity. Thus, our results will be applicable to both protostellar (Herbig-Haro) jets and optical jets from active galactic nuclei. We present analytical solutions to the dispersion relations in useful limits and solve the dispersion relations numerically over a broad range of perturbation frequencies. We find that the growth rates and wavelengths of the unstable Kelvin-Helmholtz (K-H) modes are significantly different from the adiabatic limit, and that the form of the cooling function strongly affects the results. In particular, if the cooling curve is a steep function of temperature in the neighborhood of the equilibrium state, then the growth of K-H modes is reduced relative to the adiabatic jet. On the other hand, if the cooling curve is a shallow function of temperature, then the growth of K-H modes can be enhanced relative to the adiabatic jet by the increase in cooling relative to heating in overdense regions. Inclusion of a dynamically important magnetic field does not strongly modify the important differences between an adiabatic jet and a cooling jet, provided the jet is highly supermagnetosonic and not magnetic pressure-dominated. In the latter case, the unstable modes behave more like the transmagnetosonic magnetic pressure-dominated adiabatic limit. We also plot fluid displacement surfaces associated with the various waves in a cooling jet in order to predict the structures that might arise in the nonlinear regime. This analysis predicts that low-frequency surface waves and the lowest order body modes will be the most effective at producing observable features in

  8. Operational Characteristics of Two Commercially Available Personal Cooling Vests

    Ku, Yu-Tsuan E.; Lee, Hank C.; Montgomery, Leslie D.; Webbon, Bruce W.; Luna, Bernadette (Technical Monitor)

    1996-01-01

    Personal thermoregulatory systems which provide chest cooling are used in the industrial and aerospace environments to alleviate thermal stress. However, little information is available regarding the physiologic and circulatory changes produced by routine operation of these systems. The objectives of this study were to compare the effectiveness of two passive cooling vests, and to measure the body temperature and circulatory changes produced by each cooling vest configuration. A Life Enhancement Technologies, (LET) ice vest garment and a Steele, Inc. vest were used to cool the chest region of 11 male subjects (25 to 55 yr) in this study. Calf, forearm and finger blood flows were measured using a tetrapolar impedance rheograph. The subjects, seated in an upright position at normal room temperature (approximately 21 C) were tested for 60 min. with the cooling system operating at its maximum cooling capacity. Blood flows were recorded continuously using a computer data acquisition system with a sampling frequency of 250 Hz. Oral, right and left ear temperatures and cooling system parameters were logged manually every 5 min. Arm, leg, chest and rectal temperatures; heart rate; respiration; and an activity index were recorded continuously on a U.F.I., Inc. Biolog ambulatory monitor. No significant differences were found in either the oral or ear temperature responses to the two vests. However, the rectal and mean skin temperatures at the end of the cooling period were both significantly lower (P less than 0.05), approximately 0.2 and 1.9 C, respectively for the LET vest than for the Steele garment. These data show that different vest configurations may produce different thermal responses in healthy male subjects which should be considered in the use of these cooling garments.

  9. Impingement jet cooling in gas turbines

    Amano, R S

    2014-01-01

    Due to the requirement for enhanced cooling technologies on modern gas turbine engines, advanced research and development has had to take place in field of thermal engineering. Impingement jet cooling is one of the most effective in terms of cooling, manufacturability and cost. This is the first to book to focus on impingement cooling alone.

  10. Cooled snubber structure for turbine blades

    Mayer, Clinton A; Campbell, Christian X; Whalley, Andrew; Marra, John J

    2014-04-01

    A turbine blade assembly in a turbine engine. The turbine blade assembly includes a turbine blade and a first snubber structure. The turbine blade includes an internal cooling passage containing cooling air. The first snubber structure extends outwardly from a sidewall of the turbine blade and includes a hollow interior portion that receives cooling air from the internal cooling passage of the turbine blade.

  11. Bunched Beam Cooling in the Fermilab Recycler

    Neuffer, David V; Burov, Alexey; Nagaitsev, Sergei

    2005-01-01

    Stochastic cooling with bunched beam in a linear bucket has been obtained and implemented operationally in the fermilab recycler. In this implementation the particle bunch length is much greater than the cooling system wavelengths. The simultaneous longitudinal bunching enables cooling to much smaller longitudinal emittances than the coasting beam or barrier bucket system. Characteristics and limitations of bunched beam stochastic cooling are discussed.

  12. New cooling regulation technology of secondary cooling station in DCS

    Zhou, Xuan; Yan, Jun-wei; Zhu, Dong-sheng; Liu, Fei-long; Lei, Jun-xi [The Key Lab of Enhanced Heat Transfer and Energy Conservation of Ministry of Education, School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641 (China); Liang, Lie-quan [The Key Lab of E-Commerce Market Application Technology of Guangdong Province, Guangdong University of Business Studies, Guangzhou 510320 (China)

    2008-07-01

    In this paper, a kind of new control technology of secondary cooling station (constant flow rate/variable temperature difference) in district cooling system (DCS) is proposed in view of serial consequences including low efficiency and high operating cost caused by low temperature of supply water in DCS. This technology has been applied in DCS of Guangzhou University City. The result has already indicated that such technology can increase the supply and return temperatures of buildings, return water temperature of primary side in the plate heat exchanger unit, moreover, the efficiency of both the chiller and the whole system are improved significantly. (author)

  13. Axion Cooling of Neutron Stars

    Sedrakian, Armen

    2015-01-01

    Cooling simulations of neutron stars and their comparison with the data from thermally emitting X-ray sources puts constraints on the properties of axions, and by extension of any light pseudo-scalar dark matter particles, whose existence has been postulated to solve the strong-CP problem of QCD. We incorporate the axion emission by pair-breaking and formation processes by $S$- and $P$-wave nucleonic condensates in a benchmark code for cooling simulations as well as provide fit formulae for the rates of these processes. Axion cooling of neutron stars has been simulated for 24 models covering the mass range 1 to 1.8 solar masses, featuring non-accreted iron and accreted light element envelopes, and a range of nucleon-axion coupling. The models are based on an equation state predicting conservative physics of superdense nuclear matter that does not allow for onset of fast cooling processes induced by phase transitions to non-nucleonic forms of matter or high proton concentration. The cooling tracks in the tempe...

  14. Newton's law of cooling revisited

    The cooling of objects is often described by a law, attributed to Newton, which states that the temperature difference of a cooling body with respect to the surroundings decreases exponentially with time. Such behaviour has been observed for many laboratory experiments, which led to a wide acceptance of this approach. However, the heat transfer from any object to its surrounding is not only due to conduction and convection but also due to radiation. The latter does not vary linearly with temperature difference, which leads to deviations from Newton's law. This paper presents a theoretical analysis of the cooling of objects with a small Biot number. It is shown that Newton's law of cooling, i.e. simple exponential behaviour, is mostly valid if temperature differences are below a certain threshold which depends on the experimental conditions. For any larger temperature differences appreciable deviations occur which need the complete nonlinear treatment. This is demonstrated by results of some laboratory experiments which use IR imaging to measure surface temperatures of solid cooling objects with temperature differences of up to 300 K.

  15. National solar heating and cooling programs

    Blum, S; Allen, J [eds.

    1979-08-01

    This document is a compilation of status reports on the national solar heating and cooling programs of seventeen countries participating in the Committee on the Challenges of Modern Society's Solar Energy Pilot Study. These reports were presented in two special sessions of the 25th Congress of the International Solar Energy Society held in May 1979, in Atlanta, Georgia, USA. This information exchange activity was part of the two-year follow up (1978-1980) of the Solar Energy Pilot Study, which ended in October 1978.

  16. A frictional cooling demonstration experiment with protons

    Muon cooling is the main technological obstacle in the building of a muon collider. A muon cooling scheme based on Frictional Cooling holds promise in overcoming this obstacle. An experiment designed to demonstrate the Frictional Cooling concept using protons was undertaken. Although the results were inconclusive in the observation of cooling, the data allowed for the qualification of detailed simulations which are used to simulate the performance of a muon collider

  17. Direct Liquid Cooling for Electronic Equipment

    Coles, Henry

    2014-01-01

    This report documents a demonstration of an electronic--equipment cooling system in the engineering prototype development stage that can be applied in data centers. The technology provides cooling by bringing a water--based cooling fluid into direct contact with high--heat--generating electronic components. This direct cooling system improves overall data center energy efficiency in three ways: High--heat--generating electronic components are more efficiently cooled directly using wat...

  18. Strangeness in Neutron Star Cooling

    Lim, Yeunhwan; Lee, Chang-Hwan

    2016-01-01

    We study the thermal evolution of neutron stars in the presence of hyperons or kaons in the core. Our results indicate that the nucleon and hyperon direct Urca processes play crucial roles for the cooling of neutron stars. The presence of hyperons drives fast cooling mechanisms in two ways: 1) it allows the hyperon direct Urca prior to the nucleon direct Urca, 2) and it makes the nucleon direct Urca more feasible by reducing the neutron Fermi momentum. We found that the neutron star equation of state (EOS) with hyperons can be consistent with both mass and temperature observations. We also found that the neutron star EOS with kaon condensation can be consistent with observations, even though the cooling behavior is seldom useful to identify or isolate the effect of kaon condensation.

  19. Predicting cooling tower plume dispersion

    An assessment of the effects of visible cooling tower plumes on the local environment can be a necessary part of any proposal for a new large industrial process. Predictions of the dispersion of plumes from cooling towers are based on methods developed for chimney emissions. However, the kinds of criteria used to judge the acceptability of cooling tower plumes are different from those used for stack plumes. The frequency of long elevated plumes and the frequency of ground fogging are the two main issues. It is shown that events associated with significant plumes visibility are dependent both on the operating characteristics of the tower and on the occurrence of certain meteorological conditions. The dependence on atmospheric conditions is shown to be fairly complex and simple performance criteria based on the exit conditions from the tower are not sufficient for assessments. (author)

  20. Emergency cooling apparatus for reactor

    A nuclear reactor is described which has the core surrounded by coolant and an inert cover gas all sealed within a container, an emergency cooling apparatus employing a detector that will detect cover gas or coolant, particularly liquid sodium, leaking from the container of the reactor, to release a heat exchange material that is inert to the coolant, which heat exchange material is cooled during operation of the reactor. The heat exchange material may be liquid niitrogen or a combination of spheres and liquid nitrogen, for example, and is introduced so as to contact the coolant that has leaked from the container quickly so as to rapidly cool the coolant to prevent or extinguish combustion. (Official Gazette)

  1. Permeability enhancement by shock cooling

    Griffiths, Luke; Heap, Michael; Reuschlé, Thierry; Baud, Patrick; Schmittbuhl, Jean

    2015-04-01

    The permeability of an efficient reservoir, e.g. a geothermal reservoir, should be sufficient to permit the circulation of fluids. Generally speaking, permeability decreases over the life cycle of the geothermal system. As a result, is usually necessary to artificially maintain and enhance the natural permeability of these systems. One of the methods of enhancement -- studied here -- is thermal stimulation (injecting cold water at low pressure). This goal of this method is to encourage new thermal cracks within the reservoir host rocks, thereby increasing reservoir permeability. To investigate the development of thermal microcracking in the laboratory we selected two granites: a fine-grained (Garibaldi Grey granite, grain size = 0.5 mm) and a course-grained granite (Lanhelin granite, grain size = 2 mm). Both granites have an initial porosity of about 1%. Our samples were heated to a range of temperatures (100-1000 °C) and were either cooled slowly (1 °C/min) or shock cooled (100 °C/s). A systematic microstructural (2D crack area density, using standard stereological techniques, and 3D BET specific surface area measurements) and rock physical property (porosity, P-wave velocity, uniaxial compressive strength, and permeability) analysis was undertaken to understand the influence of slow and shock cooling on our reservoir granites. Microstructurally, we observe that the 2D crack surface area per unit volume and the specific surface area increase as a result of thermal stressing, and, for the same maximum temperature, crack surface area is higher in the shock cooled samples. This observation is echoed by our rock physical property measurements: we see greater changes for the shock cooled samples. We can conclude that shock cooling is an extremely efficient method of generating thermal microcracks and modifying rock physical properties. Our study highlights that thermal treatments are likely to be an efficient method for the "matrix" permeability enhancement of

  2. Sodium-cooled nuclear reactors

    This book first explains the choice of sodium-cooled reactors by outlining the reasons of the choice of fast neutron reactors (fast neutrons instead of thermal neutrons, recycling opportunity for plutonium, full use of natural uranium, nuclear waste optimization, flexibility of fast neutron reactors in nuclear material management, fast neutron reactors as complements of water-cooled reactors), and by outlining the reasons for the choice of sodium as heat-transfer material. Physical, chemical, and neutron properties of sodium are presented. The second part of the book first presents the main design principles for sodium-cooled fast neutron reactors and their core. The third part proposes an historical overview and an assessment of previously operated sodium-cooled fast neutron reactors (French reactors from Rapsodie to Superphenix, other reactors in the world), and an assessment of the main incidents which occurred in these reactors. It also reports the experience and lessons learned from the dismantling of various sodium-cooled fast breeder reactors in the world. The next chapter addresses safety issues (technical and safety aspects related to the use of sodium) and environmental issues (dosimetry, gaseous and liquid releases, solid wastes, and cooling water). Then, various technological aspects of these reactors are addressed: the energy conversion system, main components, sodium chemistry, sodium-related technology, advances in in-service inspection, materials used in reactors and their behaviour, and fuel system. The next chapter addresses the fuel cycle in these reactors: its integrated specific character, report of the French experience in fast neutron reactor fuel processing, description of the transmutation of minor actinides in these reactors. The last chapter proposes an overview of reactors currently projected or under construction in the world, presents the Astrid project, and gives an assessment of the economy of these reactors. A glossary and an index

  3. Multiple views of magnetism in cool stars

    Morin, J; Reiners, A; Shulyak, D; Beeck, B; Hallinan, G; Hebb, L; Hussain, G; Jeffers, S V; Kochukhov, O; Vidotto, A; Walkowicz, L

    2012-01-01

    Magnetic fields are regarded as a crucial element for our understanding of stellar physics. They can be studied with a variety of methods which provide complementary - and sometimes contradictory - information about the structure, strength and dynamics of the magnetic field and its role in the evolution of stars. Stellar magnetic fields can be investigated either with direct methods based on the Zeeman effect or through the observation of activity phenomena resulting from the interaction of the field with the stellar atmosphere. In this Cool Stars XVII Splinter Session we discussed the results obtained by the many ongoing studies of stellar activity and direct studies of surface magnetic fields, as well as the state- of-the-art techniques on which they are based. We show the strengths and limitations of the various approaches currently used and to point out their evolution as well as the interest of coupling various magnetism and activity proxies.

  4. Theoretical analysis of the performance of different cooling strategies with the concept of cool exergy

    Kazanci, Ongun Berk; Shukuya, Masanori; Olesen, Bjarne W.

    2016-01-01

    The whole chains of exergy flows for different cooling systems were compared. The effects of cooling demand (internal vs. external solar shading), space cooling method (floor cooling vs. air cooling with ventilation system), and the availability of a nearby natural heat sink (intake air for the v...

  5. Internally-cooled cabled superconductors cooled with helium II

    Niobium-titanium superconductors maintained at sublambda temperatures provide an alternative to helium cooled niobium-3-tin superconductors operating in the 4.2 to 5 K temperature range. The subject paper examines the replacement of supercritical HeI with subcooled HeII in a slightly modified MIT-12 T test coil. Both steady-state and transient heat loads are considered

  6. Unparticle effects in supernovae cooling

    Recently H. Georgi suggested that a scale-invariant unparticle U sector with an infrared fixed point at high energy can couple with the standard model matter via a higher-dimensional operator suppressed by a high cutoff scale. Intense phenomenological search of this unparticle sector in the collider and flavor physics context has already been made. Here we explore its impact in cosmology, particularly its possible role in the supernovae cooling. We found that the energy-loss rate (and thus the cooling) is strongly dependent on the effective scale ΛU and the anomalous dimension dU of this unparticle theory

  7. Cooling towers in the landscape

    The cooling tower as a large technical construction is one of the most original industrial buildings. It sticks out as an outlandish element in our building landscape, a giant which cannot be compared with the traditional forms of technical buildings. If it is constructed as a reinforced-concrete hyperboloid, its shape goes beyond all limits of building construction. Judgment of these highly individual constructions is only possible by applying a novel standard breaking completely with tradition. This new scale of height and dimension in industrial construction, and in particular the modern cooling tower, requires painstaking care and design and adaptation to the landscape around it. (orig.)

  8. Gas-cooled nuclear reactor

    The invention aims at simplying gas-cooled nuclear reactors. For the cooling gas, the reactor is provided with a main circulation system comprising one or several energy conversion main groups such as gas turbines, and an auxiliary circulation system comprising at least one steam-generating boiler heated by the gas after its passage through the reactor core and adapted to feed a steam turbine with motive steam. The invention can be applied to reactors the main groups of which are direct-cycle gas turbines

  9. The chlorination of cooling water

    After reviewing the means of fighting biological pollution of cooling water circuits in nuclear power stations, the authors describe the chlorination treatment methods used by EDF. This deals with the massive shock chlorination of the cooling towers and the continuous low-level chlorination of coastal nuclear power stations. In both areas, the Research and Development Board of EDF has carried out and encouraged research with the aim of improving circuit protection, while still protecting the aquatic eco-system against damage that might be caused by waste chlorinated water

  10. Real-Time Closed Loop Modulated Turbine Cooling

    Shyam, Vikram; Culley, Dennis E.; Eldridge, Jeffrey; Jones, Scott; Woike, Mark; Cuy, Michael

    2014-01-01

    It has been noted by industry that in addition to dramatic variations of temperature over a given blade surface, blade-to-blade variations also exist despite identical design. These variations result from manufacturing variations, uneven wear and deposition over the life of the part as well as limitations in the uniformity of coolant distribution in the baseline cooling design. It is proposed to combine recent advances in optical sensing, actuation, and film cooling concepts to develop a workable active, closed-loop modulated turbine cooling system to improve by 10 to 20 the turbine thermal state over the flight mission, to improve engine life and to dramatically reduce turbine cooling air usage and aircraft fuel burn. A reduction in oxides of nitrogen (NOx) can also be achieved by using the excess coolant to improve mixing in the combustor especially for rotorcraft engines. Recent patents filed by industry and universities relate to modulating endwall cooling using valves. These schemes are complex, add weight and are limited to the endwalls. The novelty of the proposed approach is twofold 1) Fluidic diverters that have no moving parts are used to modulate cooling and can operate under a wide range of conditions and environments. 2) Real-time optical sensing to map the thermal state of the turbine has never been attempted in realistic engine conditions.

  11. In-Vessel Storage Cooling Analysis in PGSFR

    Yoon, Jung; Lee, Tae Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The IVS is the place where store the spent fuel temporarily. It is located in the annular space of the reactor core outside, and the spent fuel is stored for two cycles in IVS to reduce the decay heat and radioactivity. A total of 60 spent fuel can be stored in IVS, the minimum distance between spent fuels is more than 20 mm. The spent fuel is fixed in such a way that the nose piece is mounted on the receptacle, which is the same way as the core. Since the spent fuel stored in IVS generates the decay heat continuously, it is necessary to cool the spent fuel during the storage period. However, it is not possible to cool the spent fuel by using cold sodium in the inlet plenum because the orifice hole in the receptacle is blocked. In this study, the cooling performance of spent fuels in IVS by the natural convection due to the temperature difference between hot pool and IVS inside using CFD is assessed. The IVS cooling performance analysis using natural convection due to the temperature difference between the IVS and hot pool is evaluated by CFD. The analyses in various geometry and boundary condition are performed. For all cases, the temperature at the active bundle outlet is higher than 590 .deg. C. Therefore, the spent fuel cooling in IVS using natural convection is difficult to expect the cooling effect.

  12. Feasibility test of the concept of long-term passive cooling system of emergency cooldown tank

    Highlights: • The concept of long-term passive cooling system of emergency cooldown tank (ECT). • Existing natural circulation of steam from ECT and measurement of its condensing flow. • Evaluation of cooling capacity and heat transfer of air-cooled condensing heat exchanger. - Abstract: When a passive cooling system is activated in the accident of a nuclear reactor, the water in the emergency cooldown tank of that system will eventually be fully depleted by evaporation. If, however, the evaporating water could be returned to the tank through an air-cooled condensing heat exchanger mounted on top of the tank, the passive cooling system could provide cooling for an extended period. This feasibility of new concept of long-term passive cooling with an emergency cooldown tank was tested by performing an energy balance test with a scaled-down experimental setup. As a result, it was determined that a naturally circulating steam flow can be used to refill the tank. For an air-cooled heat exchanger, the cooling capacity and air-side natural convective heat transfer coefficient were obtained to be 37% of the heat load and between 9 and 10.2 W/m2/K depending on the heat load, respectively. Moreover, it was clearly verified that the water level in the emergency cooldown tank could be maintained over the long-term operation of the passive cooling system

  13. Liquid pump for astronaut cooling

    Carson, M. A.

    1972-01-01

    The Apollo portable life support system water-recirculation pump used for astronaut cooling is described. The problems associated with an early centrifugal pump and how these problems were overcome by the use of a new diaphragm pump are discussed. Performance comparisons of the two pump designs are given. Developmental problems and flight results with the diaphragm pump are discussed.

  14. Cooling clothing utilizing water evaporation

    Sakoi, Tomonori; Tominaga, Naoto; Melikov, Arsen Krikor;

    2014-01-01

    . To prevent wet discomfort, the T-shirt was made of a polyester material having a water-repellent silicon coating on the inner surface. The chest, front upper arms, and nape of the neck were adopted as the cooling areas of the human body. We conducted human subject experiments in an office with air...

  15. Cool Runnings For String 2

    2001-01-01

    String 2 is a series of superconducting magnets that are prototypes of those which will be installed in the LHC. It was cooled down to 1.9 Kelvin on September 14th. On Thursday last week, the dipoles of String 2 were successfully taken to nominal current, 11850 A.

  16. Cooling of the ISIS target

    The paper describes the methods used to analyse and predict cooling of the uranium target of the ISIS facility at the Rutherford Appleton Laboratory by means of a combination of computer models (using the PHOENICS finite difference package) and practical tests. (author)

  17. A cool present for LEIR

    2005-01-01

    LEIR (Low Energy Ion Ring), which will supply lead ions to the LHC experiments, has taken delivery of one of its key components, its electron cooling system. From left to right, Gérard Tranquille, Virginia Prieto and Roland Sautier, in charge of the electron cooling system for LEIR at CERN, and Christian Lacroix, in charge of installation for the LEIR machine. On 16 December, the day before CERN's annual closure, the LEIR teams received a rather impressive Christmas present. The "parcel" from Russia, measuring 7 metres in length and 4 metres in height, weighed no less than 20 tonnes! The component will, in fact, be one of the key elements of the future LEIR, namely its electron cooling system. LEIR is one of the links in the injector chain that will supply lead ions to the LHC experiments, in particular ALICE (see Bulletin No. 28/2004 of 5 July 2004), within the framework of the I-LHC Project. The electron cooling system is designed to reduce and standardise transverse ion velocity. This focuses the bea...

  18. History: Cooling and societal change

    Haldon, John

    2016-03-01

    The rise and fall of civilizations over the past two millennia was set against a backdrop of climate change. High-resolution climate records evince a link between societal change and a period of cooling in the sixth and seventh centuries.

  19. Inductive cooling in quantum magnetomechanics

    Romero-Sanchez, Erick; Twamley, Jason; Bowen, Warwick P.; Vanner, Michael R.

    Coupling to light or microwave fields allows quantum control of the motion of a mechanical oscillator, and offers prospects for precision sensing, quantum information systems, and tests of fundamental physics. In cavity electromechanics ground state cooling has been achieved using resolved sideband cooling. Here we present an alternative approach based on a magnetomechanical system that inductively couples an LC resonator to a mechanical oscillator. The experimental setup consists of a micro cantilever with a pyramidal magnetic tip attached at the end of the beam. The sharp end of the magnetic tip is positioned close to the planar microfabricated inductor of the LC resonator. The displacement in the position of the end of the cantilever generates a change in flux through the coil inducing an electromotive force in the circuit. The current in the LC resonator generates a magnetic field, and then a force between the tip and the coil. When they are strongly coupled and the mechanical resonance frequency ωm exceeds the electrical decay rate of the resonator γe, resolved sideband cooling can be used to cool the mechanics. We present estimations for the coupling rates and the experimental parameters required for these experiments. E. Romero acknowledges to CONACyT.

  20. Prediction of nongaseous fission products behavior in the primary cooling system of high temperature gas-cooled reactor

    In high temperature gas-cooled reactors (HTGRs), some amounts of fission products (FPs) are released mainly from fuel with failed coatings and are transported in the primary cooling system with the primary coolant during normal operation. In that case, condensable FPs plateout on the inner surface of components in the primary cooling system. On the other hand, since the HTGRs use helium gas as primary coolant, the primary coolant is not activated itself and very small amount of corrosion products is generated. Then, γ-ray emitted from the FPs becomes main source in shielding design of the HTGRs, and not only release amount from fuel but also plateout distributions of the FPs should be properly evaluated. Therefore, prediction of plateout behavior in the primary cooling system of HTGRs was carried out based on the calculation result of plateout distribution in High Temperature Engineering Test Reactor. Before the calculation, analytical model was verified by comparison with experimentally obtained plateout distributions and the applicability of the model to predict the plateout distributions in the primary cooling system of HTGR was certified. This report describes the predicted result of plateout distribution in the primary cooling system of HTGR together with the verification result of the analytical model. (author)

  1. Cool Cluster Correctly Correlated

    Sergey Aleksandrovich Varganov

    2005-12-17

    Atomic clusters are unique objects, which occupy an intermediate position between atoms and condensed matter systems. For a long time it was thought that physical and chemical properties of atomic dusters monotonically change with increasing size of the cluster from a single atom to a condensed matter system. However, recently it has become clear that many properties of atomic clusters can change drastically with the size of the clusters. Because physical and chemical properties of clusters can be adjusted simply by changing the cluster's size, different applications of atomic clusters were proposed. One example is the catalytic activity of clusters of specific sizes in different chemical reactions. Another example is a potential application of atomic clusters in microelectronics, where their band gaps can be adjusted by simply changing cluster sizes. In recent years significant advances in experimental techniques allow one to synthesize and study atomic clusters of specified sizes. However, the interpretation of the results is often difficult. The theoretical methods are frequently used to help in interpretation of complex experimental data. Most of the theoretical approaches have been based on empirical or semiempirical methods. These methods allow one to study large and small dusters using the same approximations. However, since empirical and semiempirical methods rely on simple models with many parameters, it is often difficult to estimate the quantitative and even qualitative accuracy of the results. On the other hand, because of significant advances in quantum chemical methods and computer capabilities, it is now possible to do high quality ab-initio calculations not only on systems of few atoms but on clusters of practical interest as well. In addition to accurate results for specific clusters, such methods can be used for benchmarking of different empirical and semiempirical approaches. The atomic clusters studied in this work contain from a few atoms

  2. Feasibility and safety of passive cooling in a cohort of asphyxiated newborn infants

    Daetwyler, Karin; Brotschi, Barbara; Berger, Thomas M.; Wagner, Bendicht Peter

    2013-01-01

    OBJECTIVE: Therapeutic hypothermia has become a standard neuroprotective treatment in term newborn infants following perinatal asphyxia. Active cooling with whole body surface or head cooling is complex, expensive and often associated with initial hypothermic overshoot. We speculated that passive cooling might suffice to induce and maintain hypothermia. METHODS: We analysed 18 asphyxiated term newborns treated with hypothermia in three tertiary neonatal and paediatric intensive care units....

  3. Vapor Jet Ejector Used To Generate Free Waste Heat Driven Cooling In Military Environmental Cooling Units

    Elbel, Stefan; Bowers, Chad D.; Reichle, Manuel; Cristiani, Jonathan M.; Hrnjak, Predrag S.

    2012-01-01

    The waste heat driven vapor jet ejector cooling cycle is a very promising approach to produce ‘free’ cooling by utilizing low-grade energy sources. The mechanism behind ejector-based waste heat cooling is very different from absorption or adsorption cooling technologies that are also aimed at producing heat driven cooling. The ejector cooling system is actually more closely related to vapor compression technology, in which an ejector, a waste heat source, and a liquid pump are used to replace...

  4. Gas turbine heat transfer and cooling technology

    Han, Je-Chin; Ekkad, Srinath

    2012-01-01

    FundamentalsNeed for Turbine Blade CoolingTurbine-Cooling TechnologyTurbine Heat Transfer and Cooling IssuesStructure of the BookReview Articles and Book Chapters on Turbine Cooling and Heat TransferNew Information from 2000 to 2010ReferencesTurbine Heat TransferIntroductionTurbine-Stage Heat TransferCascade Vane Heat-Transfer ExperimentsCascade Blade Heat TransferAirfoil Endwall Heat TransferTurbine Rotor Blade Tip Heat TransferLeading-Edge Region Heat TransferFlat-Surface Heat TransferNew Information from 2000 to 20102.10 ClosureReferencesTurbine Film CoolingIntroductionFilm Cooling on Rotat

  5. Multi-pass cooling for turbine airfoils

    Liang, George

    2011-06-28

    An airfoil for a turbine vane of a gas turbine engine. The airfoil includes an outer wall having pressure and suction sides, and a radially extending cooling cavity located between the pressure and suction sides. A plurality of partitions extend radially through the cooling cavity to define a plurality of interconnected cooling channels located at successive chordal locations through the cooling cavity. The cooling channels define a serpentine flow path extending in the chordal direction. Further, the cooling channels include a plurality of interconnected chambers and the chambers define a serpentine path extending in the radial direction within the serpentine path extending in the chordal direction.

  6. A combined capillary cooling system for cooling fuel cells

    Silva, Ana Paula; Pelizza, Pablo Rodrigo; Galante, Renan Manozzo; Bazzo, Edson [Universidade Federal de Santa Catarina (LabCET/UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Combustao e Engenharia de Sistemas Termicos], Emails: ana@labcet.ufsc.br, pablo@labcet.ufsc.br, renan@labcet.ufsc.br, ebazzo@emc.ufsc.br

    2010-07-01

    The operation temperature control has an important influence over the PEMFC (Proton Exchange Membrane Fuel Cell) performance. A two-phase heat transfer system is proposed as an alternative for cooling and thermal control of PEMFC. The proposed system consists of a CPL (Capillary Pumped Loop) connected to a set of constant conductance heat pipes. In this work ceramic wick and stainless mesh wicks have been used as capillary structure of the CPL and heat pipes, respectively. Acetone has been used as the working fluid for CPL and deionized water for the heat pipes. Experimental results of three 1/4 inch stainless steel outlet diameter heats pipes and one CPL have been carried out and presented in this paper. Further experiments are planned coupling the proposed cooling system to a module which simulates the fuel cell. (author)

  7. Deposit control in process cooling water systems

    In order to achieve efficient heat transfer in cooling water systems, it is essential to control the fouling of heat exchanger surfaces. Solubilities of scale forming salts, their growth into crystals, and the nature of the surfaces play important roles in the deposition phenomenon. Condensed phosphates, organic polymers and compounds like phosphates are effective in controlling deposition of scale forming salts. The surface active agents inhibit crystal growth and modify the crystals of the scale forming salts, and thus prevent deposition of dense, uniformly structured crystalline mass on the heat transfer surface. Understanding the mechanism of biofouling is essential to control it by surface active agents. Certain measures taken in the plant, such as back flushing, to control scaling, sometimes may not be effective and can be detrimental to the system itself. (author)

  8. Solar-driven high temperature radiant cooling

    SONG ZhaoPei; WANG RuZhu; ZHAI XiaoQiang

    2009-01-01

    Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller's COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%.According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion.

  9. Study of a Two-Pipe Chilled Beam System for both Cooling and Heating of Office Buildings

    Gordnorouzi, Rouzbeh; Hultmark, Göran; Afshari, Alireza;

    Active chilled beam systems are used to provide heating and cooling in order to achieve comfortable thermal indoor climate. For heating and cooling applications, an active chilled beam has two water circuits comprising four pipes that supply warm and cold water respectively to the beam coil...... according to the space demand. Lindab Comfort A/S has introduced an active chilled beam system which has just one water circuit (two pipes) that is used for both heating and cooling. The concept is based on high temperature cooling and low temperature heating. In this study the energy saving potential of...... the new two-pipe active chilled beam system is investigated....

  10. Active cooling convectors in the ''Altstadt-Palais'' building. Feng Shui criteria and users' wishes were considered; Aktive Kuehlkonvektoren im Altstadt-Palais. Feng Shui-Kriterien und Nutzerwuensche beruecksichtigen

    Schmid, Wolfgang

    2009-07-01

    Modern air conditioning systems are not chosen for technical and economic aspects alone, but there are various boundary conditions that are generally considered. In the case of the Altstadt-Palais building at Karl-Scharnagl-Ring, Munich, which has an office floor space of about 9,800 m{sup 2}, also Feng Shui criteria were taken into account apart from 'normal' criteria like room flexibility, thermal comfort, and economic efficiency. The new system has cooling convectors with primary air supply that are integrated in the ceilings. (orig.)

  11. Turbine airfoil with ambient cooling system

    Campbell, Jr, Christian X.; Marra, John J.; Marsh, Jan H.

    2016-06-07

    A turbine airfoil usable in a turbine engine and having at least one ambient air cooling system is disclosed. At least a portion of the cooling system may include one or more cooling channels configured to receive ambient air at about atmospheric pressure. The ambient air cooling system may have a tip static pressure to ambient pressure ratio of at least 0.5, and in at least one embodiment, may include a tip static pressure to ambient pressure ratio of between about 0.5 and about 3.0. The cooling system may also be configured such that an under root slot chamber in the root is large to minimize supply air velocity. One or more cooling channels of the ambient air cooling system may terminate at an outlet at the tip such that the outlet is aligned with inner surfaces forming the at least one cooling channel in the airfoil to facilitate high mass flow.

  12. Theory, technology, and technique of stochastic cooling

    The theory and technological implementation of stochastic cooling is described. Theoretical and technological limitations are discussed. Data from existing stochastic cooling systems are shown to illustrate some useful techniques

  13. Efficient local personal cooling with fluctuating airflows

    Bakker, L.G.; Hoes-van Oeffelen, E.C.M.; Hordijk, G.J.; Ham, E.R. van de

    2015-01-01

    Overheating in buildings is an increasingly important issue. Various studies show that local personalized cooling can substantially improve comfort levels while saving energy. Airflows are an efficient approach for local cooling. Fluctuating airflows seem more effective and are potentially perceived

  14. Lattice Regenerative Cooling Methods (LRCM) Project

    National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate a novel cooling concept called Lattice Regenerative Cooling Methods (LRCM) for future high thrust in-space propulsion...

  15. New Directions for Evaporative Cooling Systems.

    Robison, Rita

    1981-01-01

    New energy saving technology can be applied to older cooling towers; in addition, evaporative chilling, a process that links a cooling tower to the chilling equipment, can reduce energy use by 80 percent. (Author/MLF)

  16. Semi-optimal Practicable Algorithmic Cooling

    Elias, Yuval; Weinstein, Yossi; 10.1103/PhysRevA.83.042340

    2011-01-01

    Algorithmic Cooling (AC) of spins applies entropy manipulation algorithms in open spin-systems in order to cool spins far beyond Shannon's entropy bound. AC of nuclear spins was demonstrated experimentally, and may contribute to nuclear magnetic resonance (NMR) spectroscopy. Several cooling algorithms were suggested in recent years, including practicable algorithmic cooling (PAC) and exhaustive AC. Practicable algorithms have simple implementations, yet their level of cooling is far from optimal; Exhaustive algorithms, on the other hand, cool much better, and some even reach (asymptotically) an optimal level of cooling, but they are not practicable. We introduce here semi-optimal practicable AC (SOPAC), wherein few cycles (typically 2-6) are performed at each recursive level. Two classes of SOPAC algorithms are proposed and analyzed. Both attain cooling levels significantly better than PAC, and are much more efficient than the exhaustive algorithms. The new algorithms are shown to bridge the gap between PAC a...

  17. Experimental Test of the Concept of Long-term Passive Cooling System of Emergency Cooling Tank

    Recently emergency cooling tank is a great concern of passive cooling system for the safety of nuclear reactor. For the long-term operation of secondary passive cooling system, however, water level goes down by evaporation in succession at emergency cooling tank. At the end there would be no place to dissipate heat from condensation heat exchanger due to exhausted water supply. Therefore, steam cooling heat exchanger is put on the top of emergency cooling tank to maintain appropriate water level by collecting evaporating steam. Steam cooling heat exchanger is installed inside an air chimney and evaporated steam is cooled down by air natural convection at tubes of the steam cooling heat exchanger. In this study, an experimental setup was figure out by measuring water level inside emergency cooling tank for the validation of the concept of long-term passive cooling system of emergency cooling tank. An experimental setup was figure out by measuring water level inside emergency cooling tank for the validation of the concept of long-term passive cooling system of emergency cooling tank. Natural circulation of condensing flow was identified by passive cooling system of emergency cooling tank experimentally

  18. Cooling system for reactor container

    Purpose: To effectively cool a reactor container upon reactor shutdown with no intrusion of metal corrosion products in coolants into the main steam pipe in a BWR type reactor. Constitution: A clean up system comprising a pipeway, a recycling pump, a non-regenerative heat exchanger and a primary coolant purifier and a regenerative heat exchanger is provided branched from a residual heat removing system and the clean up system is connected by way of a valve to a feedwater pipeway, as well as connected by way of the pipeway to the main steam pipeway at the midway of two main steam separation valves outside of the reactor container. This enables to prevent metal corrosion products floating on the surface of reactor water from introducing into the main steam pipe when the pressure vessel is filled with water. Then, since the pressure vessel is filled with primary coolants, the pressure vessel can be cooled uniformly in a short time. (Ikeda, J.)

  19. Information technology equipment cooling method

    Schultz, Mark D.

    2015-10-20

    According to one embodiment, a system for removing heat from a rack of information technology equipment may include a sidecar indoor air to liquid heat exchanger that cools air utilized by the rack of information technology equipment to cool the rack of information technology equipment. The system may also include a liquid to liquid heat exchanger and an outdoor heat exchanger. The system may further include configurable pathways to connect and control fluid flow through the sidecar heat exchanger, the liquid to liquid heat exchanger, the rack of information technology equipment, and the outdoor heat exchanger based upon ambient temperature and/or ambient humidity to remove heat generated by the rack of information technology equipment.

  20. Engineered design of SSC cooling ponds

    The cooling requirements of the SSC are significant and adequate cooling water systems to meet these requirements are critical to the project's successful operation. The use of adequately designed cooling ponds will provide reliable cooling for operation while also meeting environmental goals of the project to maintain streamflow and flood peaks to preconstruction levels as well as other streamflow and water quality requirements of the Texas Water Commission and the Environmental Protection Agency

  1. HIRFL-CSR electron cooling system

    Electron cooling technique will be applied to the proposed Lanzhou heavy ion cooler-storage ring (HIRFL-CSR). A electron cooling device with a maximum electron energy of 165 keV and maximum current density of 0.244 A/cm2 is planned to cool heavy ions up to energies of 300 MeV/u. The preliminary design for the cooling system is presented

  2. Peltier cooling of fermionic quantum gases

    Grenier, Charles; Georges, Antoine; Kollath, Corinna

    2014-01-01

    We propose a cooling scheme for fermionic quantum gases, based on the principles of the Peltier thermoelectric effect and energy filtering. The system to be cooled is connected to another harmonically trapped gas acting as a reservoir. The cooling is achieved by two simultaneous processes: (i) the system is evaporatively cooled and (ii) cold fermions from deep below the Fermi surface of the reservoir are injected below the Fermi level of the system, in order to fill the 'holes' in the energy ...

  3. Cooling system for modern trunk diesel locomotives

    Мошенцев, Ю. Л.; Гогоренко, А. А.; Минчев, Д. С.

    2011-01-01

    The existing and alternative schemes of engine cooling system for modern trunk diesel locomotives are considered. The method for comparison of various schemes of cooling system with the purpose to find the most compact and effective of them is offered. Slow flow systems are the most appropriate as it is shown. The optimal scheme of cooling system, that permits to increase supercharging air-cooling efficiency to 0,94…0,96 it is been selected.

  4. Gas cooled traction drive inverter

    Chinthavali, Madhu Sudhan

    2016-04-19

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  5. THE INITIAL COOLING EXPERIMENT (ICE)

    1977-01-01

    ICE was built during 1977, in a record time of 9 months, using the modified bending magnets of the g-2 muon storage ring (see 7405430). ICE was a proton and antiproton storage ring, built to verify the validity of stochastic and electron cooling for the antiproton project to be launched in 1978. More on the ICE experimental programme with 7802099. See also 7809081, 7908242.

  6. Renewables for Heating and Cooling

    NONE

    2007-07-01

    This timely report examines the technologies, current markets and relative costs for heat and cold production using biomass, geothermal and solar-assisted systems. It evaluates a range of national case studies and relevant policies. Should the successful and more cost-effective policies be implemented by other countries, then the relatively untapped economic potential of renewable energy heating and cooling systems could be better realised, resulting in potential doubling of the present market within the next few years.

  7. Thermionic cooling in semiconductor multilayers

    Full text: A solid-state refrigerator in which electrons transport heat has advantages over the conventional vapour-cycle, compressor-based domestic refrigerator since it has no moving parts, it is low-maintenance, silent, vibration-free and does not require the use of refrigerant gases. The usual approach to making an all-electrical refrigerator is by thermoelectric refrigeration. After a period of intense research in the 1950s and 60s it was realised that the efficiency of thermoelectric devices was less than, and unlikely to exceed, that of conventional compressor units. While thermoelectric cooling has found specialised applications in cases where reliability, compactness and weight are important considerations, it does not appear that thermo-electrics will ever successfully compete in the domestic market, in spite of recent advances in the design and fabrication of thermoelectric materials. A new approach to an all-electric refrigerator is to employ thermionic emission over potential barriers. A key difference between a thermoelectric device and a thermionic device is that in the former the electrons are scattered in their motion and in the latter they are not. Thus thermionic cooling, in principle, can be much more efficient than thermoelectric cooling. A radical new realisation of the thermionic refrigerator was suggested recently in which a multilayer semiconductor structure would be used. We discuss the optimisation of such a multilayer semiconductor cooling system by considering (1) electron-phonon interactions in the barriers and electrodes; (2) the detailed treatment of thermal conductivity; (3) an exact numerical solution of the heat and energy currents (in contrast to the previous approximate analytic solutions); (4) the effect of varying layer thickness across the device; and (5) the effect of varying current density across the device

  8. Aerosol influence on radiative cooling

    Grassl, Hartmut

    2011-01-01

    Aerosol particles have a complex index of refraction and therefore contribute to atmospheric emission and radiative cooling rates. In this paper calculations of the longwave flux divergence within the atmosphere at different heights are presented including water vapour and aerosol particles as emitters and absorbers. The spectral region covered is 5 to 100 microns divided into 23 spectral intervals. The relevant properties of the aerosol particles, the single scattering albedo and the extinct...

  9. Gas-cooled nuclear reactor

    The gas temperature of a hot gas loop in gas-cooled nuclear reactor plants shall be able to be modified without influencing the gas temperature of the other loops. If necessary, it should be possible to stop the loop. This is possible by means of a mixer which is places below the heat absorbing component in the hot channel and which is connected to a cold gas line. (orig.)

  10. Gas hydrate cool storage system

    Ternes, M.P.; Kedl, R.J.

    1984-09-12

    The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

  11. Workshop on phase space cooling

    A discussion is given of phase space damping (''cooling'') of particle beams. Interest in this topic derives chiefly from the possibility that antiproton beams produced by collision of an intense proton beam with a target can be compressed in phase space. This could make it possible to accumulate antiproton beams in a storage ring repeatedly, thus leading to a relatively high stacked anti p beam suitable for anti p p collisions with interesting luminosities

  12. Cooling system for electronic components

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2016-05-17

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  13. Cooling system for electronic components

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2015-12-15

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  14. Water cooling of RF structures

    We present computer codes for heat transfer in water cooled rf cavities. RF parameters obtained by SUPERFISH or analytically are operated on by a set of codes using PLOTDATA, a command-driven program developed and distributed by TRIUMF [1]. Emphasis is on practical solutions with designer's interactive input during the computations. Results presented in summary printouts and graphs include the temperature, flow, and pressure data. (authors). 4 refs., 4 figs

  15. Cryotherapy-Induced Persistent Vasoconstriction After Cutaneous Cooling: Hysteresis Between Skin Temperature and Blood Perfusion.

    Khoshnevis, Sepideh; Craik, Natalie K; Matthew Brothers, R; Diller, Kenneth R

    2016-03-01

    The goal of this study was to investigate the persistence of cold-induced vasoconstriction following cessation of active skin-surface cooling. This study demonstrates a hysteresis effect that develops between skin temperature and blood perfusion during the cooling and subsequent rewarming period. An Arctic Ice cryotherapy unit (CTU) was applied to the knee region of six healthy subjects for 60 min of active cooling followed by 120 min of passive rewarming. Multiple laser Doppler flowmetry perfusion probes were used to measure skin blood flow (expressed as cutaneous vascular conductance (CVC)). Skin surface cooling produced a significant reduction in CVC (P vasoconstriction that continues beyond the active cooling period despite skin temperatures returning toward baseline values. The significant and persistent reduction in skin perfusion may contribute to nonfreezing cold injury (NFCI) associated with cryotherapy. PMID:26632263

  16. Cooling system for superconducting magnet

    Gamble, B.B.; Sidi-Yekhlef, A.

    1998-12-15

    A cooling system is configured to control the flow of a refrigerant by controlling the rate at which the refrigerant is heated, thereby providing an efficient and reliable approach to cooling a load (e.g., magnets, rotors). The cooling system includes a conduit circuit connected to the load and within which a refrigerant circulates; a heat exchanger, connected within the conduit circuit and disposed remotely from the load; a first and a second reservoir, each connected within the conduit, each holding at least a portion of the refrigerant; a heater configured to independently heat the first and second reservoirs. In a first mode, the heater heats the first reservoir, thereby causing the refrigerant to flow from the first reservoir through the load and heat exchanger, via the conduit circuit and into the second reservoir. In a second mode, the heater heats the second reservoir to cause the refrigerant to flow from the second reservoir through the load and heat exchanger via the conduit circuit and into the first reservoir. 3 figs.

  17. SPL RF Coupler Cooling Efficiency

    Bonomi, R; Montesinos, E; Parma, V; Vande Craen, A

    2014-01-01

    Energy saving is an important challenge in accelerator design. In this framework, reduction of heat loads in a cryomodule is of fundamental importance due to the small thermodynamic efficiency of cooling at low temperatures. In particular, care must be taken during the design of its critical components (e.g. RF couplers, coldwarm transitions). In this framework, the main RF coupler of the Superconducting Proton Linac (SPL) cryomodule at CERN will not only be used for RF powering but also as the main mechanical support of the superconducting cavities. These two functions have to be accomplished while ensuring the lowest heat in-leak to the helium bath at 2 K. In the SPL design, the RF coupler outer conductor is composed of two walls and cooled by forced convection with helium gas at 4.5 K. Analytical, semi-analytical and numerical analyses are presented in order to defend the choice of gas cooling. Temperature profiles and thermal performance have been evaluated for different operating conditions; a sensitivit...

  18. Electromechanically cooled germanium radiation detector system

    We have successfully developed and fielded an electromechanically cooled germanium radiation detector (EMC-HPGe) at Lawrence Livermore National Laboratory (LLNL). This detector system was designed to provide optimum energy resolution, long lifetime, and extremely reliable operation for unattended and portable applications. For most analytical applications, high purity germanium (HPGe) detectors are the standard detectors of choice, providing an unsurpassed combination of high energy resolution performance and exceptional detection efficiency. Logistical difficulties associated with providing the required liquid nitrogen (LN) for cooling is the primary reason that these systems are found mainly in laboratories. The EMC-HPGe detector system described in this paper successfully provides HPGe detector performance in a portable instrument that allows for isotopic analysis in the field. It incorporates a unique active vibration control system that allows the use of a Sunpower Stirling cycle cryocooler unit without significant spectral degradation from microphonics. All standard isotopic analysis codes, including MGA and MGA++, GAMANL, GRPANL and MGAU, typically used with HPGe detectors can be used with this system with excellent results. Several national and international Safeguards organisations including the International Atomic Energy Agency (IAEA) and U.S. Department of Energy (DOE) have expressed interest in this system. The detector was combined with custom software and demonstrated as a rapid Field Radiometric Identification System (FRIS) for the U.S. Customs Service . The European Communities' Safeguards Directorate (EURATOM) is field-testing the first Safeguards prototype in their applications. The EMC-HPGe detector system design, recent applications, and results will be highlighted

  19. Convective cores in galactic cooling flows

    Kritsuk, A G; Müller, E

    2000-01-01

    We use hydrodynamic simulations with adaptive grid refinement to study the dependence of hot gas flows in X-ray luminous giant elliptical galaxies on the efficiency of heat supply to the gas. We consider a number of potential heating mechanisms including Type Ia supernovae and sporadic nuclear activity of a central supermassive black hole. As a starting point for this research we use an equilibrium hydrostatic recycling model (Kritsuk 1996). We show that a compact cooling inflow develops, if the heating is slightly insufficient to counterbalance radiative cooling of the hot gas in the central few kiloparsecs. An excessive heating in the centre, instead, drives a convectively unstable outflow. We model the onset of the instability and a quasi-steady convective regime in the core of the galaxy in two-dimensions assuming axial symmetry. Provided the power of net energy supply in the core is not too high, the convection remains subsonic. The convective pattern is dominated by buoyancy driven large-scale mushroom-...

  20. Solar air-conditioning-active, hybrid and passive

    Yellott, J. I.

    1981-04-01

    After a discussion of summer air conditioning requirements in the United States, active, hybrid, and passive cooling systems are defined. Active processes and systems include absorption, Rankine cycle, and a small variety of miscellaneous systems. The hybrid solar cooling and dehumidification technology of desiccation is covered as well as evaporative cooling. The passive solar cooling processes covered include convective, radiative and evaporative cooling. Federal and state involvement in solar cooling is then discussed. (LEW)

  1. Hemodynamic and Thermal Responses to Head and Neck Cooling in Men and Women

    Ku, Yu-Tsuan E.; Montgomery, Leslie D.; Carbo, Jorge E.; Webbon, Bruce W.

    1995-01-01

    Personal cooling systems are used to alleviate symptoms of multiple sclerosis and to prevent increased core temperature during daily activities. Configurations of these systems include passive ice vests and circulating liquid cooling garments (LCGs) in the forms of vests, cooling caps and combined head and neck cooling systems. However, little information is available oil the amount or heat that can be extracted from the body with these systems or the physiologic changes produced by routine operation of these systems. The objective of this study was to determine the operating characteristics and the physiologic change, produced by short term use of one commercially available thermal control system.

  2. Cooling Tests for the Silion Pixel Detectors

    Pepato, Adriano; CERN. Geneva; Giarin, M; Antinori, Federico; Carrer, N; Morando, M; Soramel, F; Segato, G F; Turrisi, R; Scarlassara, F

    2000-01-01

    Abstract Cooling tests have been performed on dummy prototypes of the Silicon Pixel Detector ladders of the Inner Tracking System of ALICE, in order to assess the merits of the proposed cooling schemes. The tests provide insight into the problems of cooling of the pixel detectors and also yield experimental parameters necessary for a numerical simulation.

  3. Early developments in solar cooling equipment

    Price, J. M.

    1978-01-01

    A brief description of a development program to design, fabricate and field test a series of solar operated or driven cooling devices, undertaken by the Marshall Space Flight Center in the context of the Solar Heating and Cooling Demonstration Act of 1974, is presented. Attention is given to two basic design concepts: the Rankine cycle principle and the use of a dessicant for cooling.

  4. Trends in HPC and Data Center Power, Packaging, and Cooling

    CERN. Geneva

    2016-01-01

    air vs liquid-cooling, and metrics to track it all will be discussed. About the speaker Michael K. Patterson is a Senior Principal Engineer in the Technical Computing Group - Systems Architecture & Pathfinding at the Intel Corporation, in Dupont, Washington, where he works in the power, thermal, and energy-efficient-performance areas of High Performance Computing. The work covers silicon level activity, through platform and rack-level solutions, and on up to interface with Data Center power and cooling technologies. He did his undergraduate work at Purdue University, received his MS degree in Management from Rensselaer Polytechnic Institute, an...

  5. Enhanced Optomechanical Cooling at High-Order Exceptional Points

    Jing, H; Lü, H; Nori, Franco

    2016-01-01

    We study mechanical cooling in systems of coupled passive (lossy) and active (with gain) optical resonators. We find that for a driving laser which is red-detuned with respect to the cavity frequency, the supermode structure of the system is radically changed, featuring the emergence of genuine high-order exceptional points. This in turn leads to giant enhancement of both the mechanical damping and the spring stiffness, facilitating low-power mechanical cooling in the vicinity of gain-loss balance. This opens up new avenues of steering micromechanical devices with exceptional points beyond the lowest-order two.

  6. Selective brain cooling and its vascular basis in diving seals.

    Blix, Arnoldus Schytte; Walløe, Lars; Messelt, Edward B; Folkow, Lars P

    2010-08-01

    Brain (T(brain)), intra-aorta (T(aorta)), latissimus dorsi muscle (T(m)) and rectal temperature (T(r)) were measured in harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals during experimental dives in 4 degrees C water. The median brain cooling was about 1 degrees C during 15 min diving, but in some cases it was as much as 2.5 degrees C. Cooling rates were slow for the first couple of minutes, but increased significantly after about 5 min of diving. The onset of cooling sometimes occurred before the start of the dive, confirming that the cooling is under cortical control, like the rest of the diving responses. T(aorta) also fell significantly, and was always lower than T(brain), while T(m) was fairly stable during dives. Detailed studies of the vascular anatomy of front flippers revealed that brachial arterial blood can be routed either through flipper skin capillaries for nutritive purposes and return through sophisticated vascular heat exchangers to avoid heat loss to the environment, or, alternatively, through numerous arterio-venous shunts in the skin and return by way of large superficial veins, which then carry cold blood to the heart. In the latter situation the extent to which the brain is cooled is determined by the ratio of carotid to brachial arterial blood flow, and water temperature, and the cooling is selective in that only those organs that are circulated will be cooled. It is concluded that T(brain) is actively down-regulated during diving, sometimes by as much as 2.5 degrees C, whereby cerebral oxygen requirements may be reduced by as much as 25% during extended dives. PMID:20639422

  7. A novel system solution for cooling and ventilation in office buildings

    Yu, Tao; Heiselberg, Per Kvols; Lei, Bo; Pomianowski, Michal Zbigniew; Zhang, Chen

    technologies and renewable energy sources have risen. Based on a literature review of natural ventilation, building thermal mass activation and diffuse ceiling ventilation, this paper proposes a new system solution combining these three technologies for cooling and ventilation in office buildings. This new...... saving potential using this solution compared with other systems. Energy saving potential for cooling occurs in summer, transitional seasons and part of winter, depending on the internal heat load level. Meanwhile, due to the large cooling potential of outside air in winter, the minimum ventilation rate......As a response to new energy policies in the building sector, office buildings have become well-insulated and highly-airtight, resulting in an increasing cooling need both in summer and in winter. In order to effectively save energy, new interests in cooling concepts using passive cooling...

  8. Design Concepts for Cooled Ceramic Matrix Composite Turbine Vanes

    Boyle, Robert

    2014-01-01

    This project demonstrated that higher temperature capabilities of ceramic matrix composites (CMCs) can be used to reduce emissions and improve fuel consumption in gas turbine engines. The work involved closely coupling aerothermal and structural analyses for the first-stage vane of a high-pressure turbine (HPT). These vanes are actively cooled, typically using film cooling. Ceramic materials have structural and thermal properties different from conventional metals used for the first-stage HPT vane. This project identified vane configurations that satisfy CMC structural strength and life constraints while maintaining vane aerodynamic efficiency and reducing vane cooling to improve engine performance and reduce emissions. The project examined modifications to vane internal configurations to achieve the desired objectives. Thermal and pressure stresses are equally important, and both were analyzed using an ANSYS® structural analysis. Three-dimensional fluid and heat transfer analyses were used to determine vane aerodynamic performance and heat load distributions.

  9. Dry storage systems with free convection air cooling

    Several design principles to remove heat from the spent fuel by free air convection are illustrated and described. The key safety considerations were felt to be: loss of coolant is impossible as the passive system uses air as a coolant; overheating is precluded because as the temperatures of the containers rises the coolant flow rate increases; mass of the storage building provides a large heat sink and therefore a rapid temperature rise is impossible; and lack of any active external support requirements makes the cooling process less likely to equipment or operator failures. An example of this type of storage already exists. The German HTGR is operated with spherical graphite fuel elements which are stored in canister and in storage cells. The concept is a double cooling system with free convection inside the cells and heat exchange via two side walls of the cell to the ambient air in the cooling ducts. Technical description of the TN 1300 cask is also presented

  10. Detectors and cooling technology for direct spectroscopic biosignature characterization

    Rauscher, Bernard J; Moseley, S H; Sadleir, John E; Stevenson, Thomas

    2016-01-01

    Direct spectroscopic biosignature characterization (hereafter "biosignature characterization") will be a major focus for future space observatories equipped with coronagraphs or starshades. Our aim in this article is to provide an introduction to potential detector and cooling technologies for biosignature characterization. We begin by reviewing the needs. These include nearly noiseless photon detection at flux levels as low as $<0.001~\\textrm{photons}~s^{-1}~\\textrm{pixel}^{-1}$ in the visible and near-IR. We then discuss potential areas for further testing and/or development to meet these needs using non-cryogenic detectors (EMCCD, HgCdTe array, HgCdTe APD array), and cryogenic single photon detectors (MKID arrays and TES microcalorimeter arrays). Non-cryogenic detectors are compatible with the passive cooling that is strongly preferred by coronagraphic missions, but would add non-negligible noise. Cryogenic detectors would require active cooling, but in return deliver nearly quantum limited performance....

  11. Radiant floor cooling coupled with dehumidification systems in residential buildings: A simulation-based analysis

    Highlights: • The floor radiant cooling in a typical apartment is analyzed. • Dehumidification devices, fan-coil and mechanical ventilation are compared. • The results are analyzed in terms of both thermal comfort and energy consumption. • The energy consumption of the dehumidifiers is higher than that of other systems. • The mechanical ventilation decreases the moisture level better than other systems. - Abstract: The development of radiant cooling has stimulated an interest in new systems based on coupling ventilation with radiant cooling. However, radiant cooling systems may cause condensation to form on an active surface under warm and humid conditions during the cooling season. This phenomenon occurs when surface temperature falls below dew point. To prevent condensation, air humidity needs to be reduced with a dehumidification device or a mechanical ventilation system. There are two main options to achieve this. The first is to use dehumidification devices that reduce humidity, but are not coupled with ventilation, i.e. devices that handle room air and leave air change to infiltrations. The second is to combine a mechanical ventilation system with dehumidifying finned coils. This study analyzes the floor radiant cooling of a typical residential apartment within a multi-storey building in three Italian climate zones by means of a detailed simulation tool. Five systems were compared in terms of both indoor thermal comfort and energy consumption: radiant cooling without dehumidification; radiant cooling with a soft dehumidification device; radiant cooling with a dehumidification device which also supplies sensible cooling; radiant cooling coupled with fan coils; and radiant cooling with a mechanical ventilation system which dehumidifies and cools

  12. Experimental evaluation of cooling efficiency of the high performance cooling device

    Nemec, Patrik; Malcho, Milan

    2016-06-01

    This work deal with experimental evaluation of cooling efficiency of cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description of cooling device, working principle of cooling device, construction of cooling device. Experimental part describe the measuring method of device cooling efficiency evaluation. The work results are presented in graphic visualization of temperature dependence of the contact area surface between cooling device evaporator and electronic components on the loaded heat of electronic components in range from 250 to 740 W and temperature dependence of the loop thermosiphon condenser surface on the loaded heat of electronic components in range from 250 to 740 W.

  13. A parametric study of solar operated cooling system

    Because of energy for air conditioning has been the fastest-growing segment of energy of consumption market in Libya and generally in north Africa, and with the realization depleting nature of fossil fuel, solar cooling of buildings which leads to the improvement of human comfort represents a potentially significant application of solar energy where the availability of solar radiation meets with the cooling load demand. This application has been shown to be technically feasible but the equipment needs further investigative research to improve its performance and feasibility. A solar operated absorption cooling system with energy storage is selected. A latent heat storage would be a space saver for such application for solar energy. A system modeling is an essential activity in order to go for system simulation. A complete solar cooling system to be modeled through the thermodynamic analysis of each system components. Resulting a package of equations used directly to the system simulation in order to predict the system performance to obtain the optimum working conditions for the selected cooling system. A computer code which is used to simulate a series of calculations was written in Fortran language according to the constructed information flow diagram and simulation program flow char. For a typical input data a set of results are reported and discussed and shows that the selected system promises to be a good choice for air conditioning application in Libya specially for large building as storehouses, shopping centers, public administrative.(Author)

  14. Strategies for increasing evaporative cooling during simulated desert patrol mission.

    Ciuha, Ursa; Grönkvist, Mikael; Mekjavic, Igor B; Eiken, Ola

    2016-02-01

    The study evaluated the efficiency of two heat dissipation strategies under simulated desert patrol missions. Ten men participated in four trials, during which they walked on a treadmill (45°C, 20% relative humidity), carrying a load of 35 kg; two 50-min walks were separated by a 20-min rest. Cooling strategies, provided by an ambient air-ventilated vest (active cooling condition, AC), or water spraying of the skin during the rest (passive cooling condition, PC), in addition to reduced clothing and open zippers, were compared to conditions with full protective (FP) clothing and naked condition (NC). Skin temperature was higher during NC (37.9 ± 0.4°C; p < 0.001), and rectal temperature and heart rate were higher during FP (38.6 ± 0.4°C, p < 0.001 and 145 ± 12, p < 0.001, respectively), compared to other conditions. Four subjects terminated the trial prematurely due to signs of heat exhaustion in FP. Both cooling strategies substantially improved evaporative cooling. PMID:26094700

  15. LFR "Lead-Cooled Fast Reactor"

    Cinotti, L; Fazio, C; Knebel, J; Monti, S; Abderrahim, H A; Smith, C; Suh, K

    2006-05-11

    development already being carried out in different institutes participating in this STREP. This is particularly true in Europe where a large R&D program associated with the development of Accelerator Driven Systems (ADS) is being actively pursued. The general objective of the ELSY project is to design an innovative lead-cooled fast reactor complemented by an analytical effort to assess the existing knowledge base in the field of lead-alloy coolants (i.e., lead-bismuth eutectic (LBE) and also lead/lithium) in order to extrapolate this knowledge base to pure lead. This analysis effort will be complemented with some limited R&D activities to acquire missing or confirmatory information about fundamental topics for ELSY that are not sufficiently covered in the ongoing European ADS program or elsewhere.

  16. Cooling solutions for high heat load optics

    Heat loads on optical components at third-generation synchrotron sources, such as the APS, present beamline designers with difficult and complex engineering problems. A number of solutions have been proposed, such as pin-post water cooling, cryogenic cooling, and liquid gallium cooling. This paper describes both a cryogenic cooling system and a liquid gallium pumping system that have been developed specifically for the APS high heat load beamlines. Also presented is a potential solution for the first mirrors on high heat load beamlines, based on liquid gallium internal cooling of a silicon carbide mirror. copyright 1996 American Institute of Physics

  17. Hydraulic works study of Golfech cooling towers

    The GOLFECH Nuclear Power Plant cooling towers (PWR 2 x 1300 MWe), built by SCAM for EDF (French National Electricity Authority), have certain characteristics, including: tower height - 178.50 metres; shell support - made up of a profiled lintel resting on piles; cooled water recovery system installed immediately below the fill; and cold water basin built outside the cooling tower. This paper deals only with the hydraulic circuit design (warm water inlet, cooled water recovery, cooled water return) with particular emphasis on the limitations of conventional methods of hydraulic sizing and, the necessity to carry out tests using models in order to dimension such works

  18. Tropical cyclone cooling combats region-wide coral bleaching.

    Carrigan, Adam D; Puotinen, Marji

    2014-05-01

    Coral bleaching has become more frequent and widespread as a result of rising sea surface temperature (SST). During a regional scale SST anomaly, reef exposure to thermal stress is patchy in part due to physical factors that reduce SST to provide thermal refuge. Tropical cyclones (TCs - hurricanes, typhoons) can induce temperature drops at spatial scales comparable to that of the SST anomaly itself. Such cyclone cooling can mitigate bleaching across broad areas when well-timed and appropriately located, yet the spatial and temporal prevalence of this phenomenon has not been quantified. Here, satellite SST and historical TC data are used to reconstruct cool wakes (n=46) across the Caribbean during two active TC seasons (2005 and 2010) where high thermal stress was widespread. Upon comparison of these datasets with thermal stress data from Coral Reef Watch and published accounts of bleaching, it is evident that TC cooling reduced thermal stress at a region-wide scale. The results show that during a mass bleaching event, TC cooling reduced thermal stress below critical levels to potentially mitigate bleaching at some reefs, and interrupted natural warming cycles to slow the build-up of thermal stress at others. Furthermore, reconstructed TC wave damage zones suggest that it was rare for more reef area to be damaged by waves than was cooled (only 12% of TCs). Extending the time series back to 1985 (n = 314), we estimate that for the recent period of enhanced TC activity (1995-2010), the annual probability that cooling and thermal stress co-occur is as high as 31% at some reefs. Quantifying such probabilities across the other tropical regions where both coral reefs and TCs exist is vital for improving our understanding of how reef exposure to rising SSTs may vary, and contributes to a basis for targeting reef conservation. PMID:24474700

  19. Comparison of Air Cooled and Evaporatively Cooled Refrigerartion Systems – A Review Paper

    V. V. Birangane; A.M.Patil

    2014-01-01

    The air cooled condensers are widely used as they are less costly and give satisfactory performance. But their performance is greatly affected by the temperature of cooling media which is ambient air. To deal this problem we can use water cooled condenser. But their cost and maintenance limit their use. The performance improvement of Air cooled condensers can be achieved by using evaporative cooling. This method may prove quiet effective and less costly. There are researchers ...

  20. Origin and prevention of infection with Legionella pneumophila through cooling towers and evaporative cooling towers

    Evaporative cooling towers and industrial ventilator cooling towers have repeatedly been described as the origin of Legionnaires' disease. This article describes the design and function of cooling towers and evaporative cooling towers, sums up knowledge on the colonization of such systems with Legionella pneumophila, and describes conditions permitting the transmission of Legionella. Furthermore, design, maintenance, cleaning and disinfection measures are indicated which are believed to reduce the risk of infection through industrial and evaporative cooling towers. (orig.)

  1. Workshop on beam cooling and related topics

    The sessions of the Workshop on Beam Cooling and Related Topics, held in Montreux from 4-8 October 1993, are reported in these Proceedings. This meeting brought together international experts in the field of accelerator beam cooling. Its purpose was to discuss the status of the different cooling techniques currently in use (stochastic, electron, ionization, heavy-ion, and laser) and their actual performances, technological implications, and future prospects. Certain theoretical principles (muon cooling, cyclotron maser cooling) were discussed and are reported on in these Proceedings. Also of interest in this Workshop was the possibility of beam crystallization in accelerators using ultimate cooling. In the first part of these Proceedings, overview talks on the various cooling techniques, their implications, present performance, and future prospects are presented. More detailed reports on all the topics are then given in the form of oral presentations or poster sessions. Finally, the chairmen and/or convenors then present summary talks. (orig.)

  2. Status of national gas cooled reactor programmes

    This report has been compiled as a central source of summary-level information on the present status of High Temperature Gas-Cooled Reactor (HTGR) programmes in the world and on future plans for the continued development and deployment of HTGRs. Most of the information concerns the programmes in the United States, Germany, Japan and the Soviet Union, countries that have had large programmes related to HTGR technology for several years. Summary-level information is also provided in the report on HTGR-related activities in several other countries who either have an increasing interest in the technology and/or who are performing some development efforts related to HTGR technology. The report contains a summary-level update on the MAGNOX and AGR programmes. This is the twelfth issue of the document, the first of which was issued in March, 1979. The report has been prepared in the IAEA Nuclear Power Technology Development Section. Figs and tabs

  3. Cooling and Heating Solid Quark Stars

    Yu, Meng

    2009-01-01

    We present here a phenomenological solid quark star pulsar model to interpret the observed thermal X-ray emission of isolated pulsars. The heat capacity for solid quark stars was found to be quite small, so that the residual internal stellar heat gained at the birth of the star could be dissipated in an extremely short timescale. However, the bombardment induced by backflowing plasma at the poles of solid quark stars would get the stars be reheated, so that long term soft X-ray emission can be sustained. Such a scenario could be used for those X-ray pulsars with significant magnetospheric activities, and their cooling processes would thus be established. Dim X-ray isolated neutron stars (XDINs) as well as compact central objects (CCOs) have been observed with dominant soft X-ray radiation combined with little magnetospheric manifestations. Such sources could be solid quark stars accreting in the propeller regime.

  4. Shutdown cooling helium circulator design considerations for MHTGR [Modular High Temperature Gas-Cooled Reactor] power plant

    The Modular High Temperature Gas-Cooled Reactor (MHTGR) plant embodies a shutdown cooling system to expedite plant cooldown for refueling, maintenance, and repair in the event that the main cooling loop is unavailable. This is a non safety related system. A key component in this system, is a helium circulator. Oriented vertically, the rotating assembly in this machine is supported on active magnetic bearings, and the radial flow compressor is driven by a submerged induction electric motor rated at 160 kW(e). This paper gives details of the circulator design considerations and includes topics related to the machine operation and maintenance, and the technology base. 12 refs., 11 figs., 3 tabs

  5. Ionization Cooling using Parametric Resonances

    Johnson, Rolland P.

    2008-06-07

    Ionization Cooling using Parametric Resonances was an SBIR project begun in July 2004 and ended in January 2008 with Muons, Inc., (Dr. Rolland Johnson, PI), and Thomas Jefferson National Accelerator Facility (JLab) (Dr. Yaroslav Derbenev, Subcontract PI). The project was to develop the theory and simulations of Parametric-resonance Ionization Cooling (PIC) so that it could be used to provide the extra transverse cooling needed for muon colliders in order to relax the requirements on the proton driver, reduce the site boundary radiation, and provide a better environment for experiments. During the course of the project, the theoretical understanding of PIC was developed and a final exposition is ready for publication. Workshops were sponsored by Muons, Inc. in May and September of 2007 that were devoted to the PIC technique. One outcome of the workshops was the interesting and somewhat unexpected realization that the beam emittances using the PIC technique can get small enough that space charge forces can be important. A parallel effort to develop our G4beamline simulation program to include space charge effects was initiated to address this problem. A method of compensating for chromatic aberrations by employing synchrotron motion was developed and simulated. A method of compensating for spherical aberrations using beamline symmetry was also developed and simulated. Different optics designs have been developed using the OptiM program in preparation for applying our G4beamline simulation program, which contains all the power of the Geant4 toolkit. However, no PIC channel design that has been developed has had the desired cooling performance when subjected to the complete G4beamline simulation program. This is believed to be the consequence of the difficulties of correcting the aberrations associated with the naturally large beam angles and beam sizes of the PIC method that are exacerbated by the fringe fields of the rather complicated channel designs that have been

  6. Confirmation of shutdown cooling effects

    Sato, Kotaro; Tabuchi, Masato; Sugimura, Naoki; Tatsumi, Masahiro

    2015-12-01

    After the Fukushima accidents, all nuclear power plants in Japan have gradually stopped their operations and have long periods of shutdown. During those periods, reactivity of fuels continues to change significantly especially for high-burnup UO2 fuels and MOX fuels due to radioactive decays. It is necessary to consider these isotopic changes precisely, to predict neutronics characteristics accurately. In this paper, shutdown cooling (SDC) effects of UO2 and MOX fuels that have unusual operation histories are confirmed by the advanced lattice code, AEGIS. The calculation results show that the effects need to be considered even after nuclear power plants come back to normal operation.

  7. Assessment of spent fuel cooling

    Ibarra, J.G.; Jones, W.R.; Lanik, G.F. [and others

    1997-02-01

    The paper presents the methodology, the findings, and the conclusions of a study that was done by the Nuclear Regulatory Commission`s Office for Analysis and Evaluation of Operational Data (AEOD) on loss of spent fuel pool cooling. The study involved an examination of spent fuel pool designs, operating experience, operating practices, and procedures. AEOD`s work was augmented in the area of statistics and probabilistic risk assessment by experts from the Idaho Nuclear Engineering Laboratory. Operating experience was integrated into a probabilistic risk assessment to gain insight on the risks from spent fuel pools.

  8. Ionization Cooling using Parametric Resonances

    Ionization Cooling using Parametric Resonances was an SBIR project begun in July 2004 and ended in January 2008 with Muons, Inc., (Dr. Rolland Johnson, PI), and Thomas Jefferson National Accelerator Facility (JLab) (Dr. Yaroslav Derbenev, Subcontract PI). The project was to develop the theory and simulations of Parametric-resonance Ionization Cooling (PIC) so that it could be used to provide the extra transverse cooling needed for muon colliders in order to relax the requirements on the proton driver, reduce the site boundary radiation, and provide a better environment for experiments. During the course of the project, the theoretical understanding of PIC was developed and a final exposition is ready for publication. Workshops were sponsored by Muons, Inc. in May and September of 2007 that were devoted to the PIC technique. One outcome of the workshops was the interesting and somewhat unexpected realization that the beam emittances using the PIC technique can get small enough that space charge forces can be important. A parallel effort to develop our G4beamline simulation program to include space charge effects was initiated to address this problem. A method of compensating for chromatic aberrations by employing synchrotron motion was developed and simulated. A method of compensating for spherical aberrations using beamline symmetry was also developed and simulated. Different optics designs have been developed using the OptiM program in preparation for applying our G4beamline simulation program, which contains all the power of the Geant4 toolkit. However, no PIC channel design that has been developed has had the desired cooling performance when subjected to the complete G4beamline simulation program. This is believed to be the consequence of the difficulties of correcting the aberrations associated with the naturally large beam angles and beam sizes of the PIC method that are exacerbated by the fringe fields of the rather complicated channel designs that have been

  9. Hot moons and cool stars

    Heller René

    2013-04-01

    Full Text Available The exquisite photometric precision of the Kepler space telescope now puts the detection of extrasolar moons at the horizon. Here, we firstly review observational and analytical techniques that have recently been proposed to find exomoons. Secondly, we discuss the prospects of characterizing potentially habitable extrasolar satellites. With moons being much more numerous than planets in the solar system and with most exoplanets found in the stellar habitable zone being gas giants, habitable moons could be as abundant as habitable planets. However, satellites orbiting planets in the habitable zones of cool stars will encounter strong tidal heating and likely appear as hot moons.

  10. Information technology equipment cooling system

    Schultz, Mark D.

    2014-06-10

    According to one embodiment, a system for removing heat from a rack of information technology equipment may include a sidecar indoor air to liquid heat exchanger that cools warm air generated by the rack of information technology equipment. The system may also include a liquid to liquid heat exchanger and an outdoor heat exchanger. The system may further include configurable pathways to connect and control fluid flow through the sidecar heat exchanger, the liquid to liquid heat exchanger, the rack of information technology equipment, and the outdoor heat exchanger based upon ambient temperature and/or ambient humidity to remove heat from the rack of information technology equipment.

  11. Thermoelectric Devices Cool, Power Electronics

    2009-01-01

    Nextreme Thermal Solutions Inc., based in Research Triangle Park, North Carolina, licensed thermoelectric technology from NASA s Jet Propulsion Laboratory. This has allowed the company to develop cutting edge, thin-film thermoelectric coolers that effective remove heat generated by increasingly powerful and tightly packed microchip components. These solid-state coolers are ideal solutions for applications like microprocessors, laser diodes, LEDs, and even potentially for cooling the human body. Nextreme s NASA technology has also enabled the invention of thermoelectric generators capable of powering technologies like medical implants and wireless sensor networks.

  12. Confirmation of shutdown cooling effects

    Sato, Kotaro, E-mail: ksato@nelted.co.jp; Tabuchi, Masato; Sugimura, Naoki; Tatsumi, Masahiro [Nuclear Engineering, Limited, 1-3-7 Tosabori Nishi-ku, Osaka-shi, Osaka 550-0001 (Japan)

    2015-12-31

    After the Fukushima accidents, all nuclear power plants in Japan have gradually stopped their operations and have long periods of shutdown. During those periods, reactivity of fuels continues to change significantly especially for high-burnup UO{sub 2} fuels and MOX fuels due to radioactive decays. It is necessary to consider these isotopic changes precisely, to predict neutronics characteristics accurately. In this paper, shutdown cooling (SDC) effects of UO{sub 2} and MOX fuels that have unusual operation histories are confirmed by the advanced lattice code, AEGIS. The calculation results show that the effects need to be considered even after nuclear power plants come back to normal operation.

  13. Theoretical insight of adsorption cooling

    Chakraborty, Anutosh

    2011-06-03

    This letter proposes and presents a thermodynamic formulation to calculate the energetic performances of an adsorption cooler as a function of pore widths and volumes of solid adsorbents. The simulated results in terms of the coefficient of performance are validated with experimental data. It is found from the present analysis that the performance of an adsorption cooling device is influenced mainly by the physical characteristics of solid adsorbents, and the characteristics energy between the adsorbent-adsorbate systems. The present study confirms that there exists a special type of silicagel having optimal physical characteristics that allows us to obtain the best performance.

  14. Effect of consecutive cooling and immobilization on catecholamine metabolism in rat tissues

    Matlina, E. S.; Waysman, S. M.; Zaydner, I. G.; Kogan, B. M.; Nozdracheva, L. V.

    1979-01-01

    The combined effect of two stressor stimuli--cooling and immobilization--acting successively on the sympathetic-adrenaline system was studied experimentally in rats that were cooled for 8 hours at 7 C on the first day and immobilized for 6 hours on the next day. The biochemical and histochemical methods used and the experimental technique involved are described in detail. The following conclusions were formulated: (1) the successive action of cooling and immobilization results in a stronger decrease in the adrenaline and noradrenaline content in the adrenal gland than that which could be due to a simple summation of the cooling and immobilization effects; (2) successive cooling and immobilization are followed by activation of catecholamine synthesis in the adrenal gland; and (3) 1-DOPA administration (45 mg/kg 3 times in 2 days) intraabdominally activated catecholamine synthesis in the adrenal glands in both the control and test animals.

  15. Effects of different cooling principles on thermal sensation and physiological responses

    Loomans, Marcel G.L.C.; De Wit, Martin H.; Lichtenbelt, Wouter D. Van Marken;

    2013-01-01

    floor and mixing ventilation, and (6) AC-R-D-F; active cooling through radiation by the floor and displacement ventilation. Though all cases were designed at PMV ≈ 0, subjective data indicate significant differences between the cases. For the prediction of thermal sensation and thermal comfort under non......Applying low exergy cooling concepts in the built environment allows reduction of use of high quality energy sources. Non-uniform thermal conditions, which may occur due to application of lowex systems, can result in discomfort. Two different cooling principles were studied: passive (through...... convection in terms of increased air velocities) and active cooling (through convection or radiation). Furthermore, two different ventilation techniques were included: mixing and displacement ventilation. Ten male subjects (age: 20-29) were exposed to six different cases: (1) PC-C-M; passive cooling through...

  16. Interplay Among Cooling, AGN Feedback, and Anisotropic Conduction in the Cool Cores of Galaxy Clusters

    Yang, H.-Y. Karen; Reynolds, Christopher S.

    2016-02-01

    Feedback from the active galactic nuclei (AGNs) is one of the most promising heating mechanisms to circumvent the cooling-flow problem in galaxy clusters. However, the role of thermal conduction remains unclear. Previous studies have shown that anisotropic thermal conduction in cluster cool cores (CCs) could drive the heat-flux-driven buoyancy instabilities (HBIs) that reorient the field lines in the azimuthal directions and isolate the cores from conductive heating from the outskirts. However, how the AGN interacts with the HBI is still unknown. To understand these interwined processes, we perform the first 3D magnetohydrodynamic simulations of isolated CC clusters that include anisotropic conduction, radiative cooling, and AGN feedback. We find the following: (1) For realistic magnetic field strengths in clusters, magnetic tension can suppress a significant portion of HBI-unstable modes, and thus the HBI is either completely inhibited or significantly impaired, depending on the unknown magnetic field coherence length. (2) Turbulence driven by AGN jets can effectively randomize magnetic field lines and sustain conductivity at ∼1/3 of the Spitzer value; however, the AGN-driven turbulence is not volume filling. (3) Conductive heating within the cores could contribute to ∼10% of the radiative losses in Perseus-like clusters and up to ∼50% for clusters twice the mass of Perseus. (4) Thermal conduction has various impacts on the AGN activity and intracluster medium properties for the hottest clusters, which may be searched by future observations to constrain the level of conductivity in clusters. The distribution of cold gas and the implications are also discussed.

  17. Enhancing the efectiveness of film cooling

    Tom I-P.Shih; Sangkwon Na

    2007-01-01

    Advanced gas turbine stages are designed to operate at increasingly higher inlet temperatures to increase thermal efficiency and specific power output.To maintain durability and reasonable life,film cooling is needed in addition to internal cooling,especially for the first stage.Film cooling lowers material temperature by forced convection inside film-cooling holes and by forming a layer of coolant about component surfaces to insulate them from the hot gases.Unfortunately,each cooling jet forms a pair of counter-rotating vortices that entrains hot gas and causes the film-cooling jet to lift off from the surface that it is intended to protect.This paper gives an overview of efforts to enhance the effectiveness of film-cooling.This paper also describes two new design concepts.One design concept seeks to minimize the entrainment of hot gases underneath of film-cooling jets by using flow-aligned blockers.The other design concept shifts the interaction between the approaching hot gas and the cooling jet to occur further above the surface by using an upstream ramp.For both design concepts,computational fluid dynamics results are presented to examine their usefulness in enhancing film-cooling effectiveness.

  18. Reactor pressure vessel cooling device

    A spray pipeline for the head of a pressure vessel is connected to a spray for the pressure vessel head of the reactor pressure vessel. The pipeline is equipped with a spray flow rate control valve for controlling the flow rate of spray jetted from the head spray to the inside of the reactor and a thermometer for spray water. A reactor pressure vessel cooling and controlling portion intakes temperature signals sent from a thermometer for the head of the pressure vessel, a thermometer for the flange of the pressure vessel and a thermometer for the body of the pressure vessel, and a thermometer for spray water. Then, it outputs restriction signal for the opening degree of the spray flow rate control valve to restrict the spray water flow rate within an appropriate range when the difference between the temperature of each portion of the pressure vessel and the temperature of spray water is increased to greater than an allowable temperature difference. With such procedures, spray operation for the head of the pressure vessel can be conducted not only upon emergency but also during reactor cooling operation. (I.N.)

  19. Heating and Cooling Protostellar Disks

    Hirose, S

    2011-01-01

    We examine heating and cooling in protostellar disks using 3-D radiation-MHD calculations of a patch of the Solar nebula at 1 AU, employing the shearing-box and flux-limited radiation diffusion approximations. The disk atmosphere is ionized by stellar X-rays, well-coupled to magnetic fields, and sustains a turbulent accretion flow driven by magneto-rotational instability, while the interior is resistive and magnetically dead. The turbulent layers heat by absorbing the light from the central star and by dissipating the magnetic fields. They are optically-thin to their own radiation and cool inefficiently. The optically-thick interior in contrast is heated only weakly, by re-emission from the atmosphere. The interior is colder than a classical viscous model, and isothermal. The magnetic fields support an extended atmosphere that absorbs the starlight 1.5 times higher than the hydrostatic viscous model. The disk thickness thus measures not the internal temperature, but the magnetic field strength. Fluctuations i...

  20. JUELICH: COSY acceleration and cooling

    The COSY cooler synchrotron at the KFA Forschungszentrum Jülich, inaugurated on 1 April, is now well on its way towards precision-defined high energy beams to open new fields for Jülich physics experiments. In two important goals, on 25 May the first beam cooled by electrons circulated inside the accelerator, then on 25 July physicists succeeded in accelerating the beam from the 270 MeV/c injection momentum to 600 MeV. Shortly after, this was pushed well above 1 GeV. Throughout the tuning process the number of stored particles increased steadily, finally peaking at 1.1 x 1011, a value compatible with the predicted limit at the injection energy. This success was the result of a painstaking search for the optimum parameter set, the commissioning crew being acutely aware that bringing such a large machine on line was a major experiment in its own right. The 3.3 GeV/c COSY machine belongs to the new class of hadron storage and cooler synchrotrons which started with CERN's LEAR low energy antiproton ring. COSY will 'sharpen' its beams to a narrow momentum spread using both electron and stochastic cooling to control the circulating particles. In addition it will provide space for internal experiments. Both features will allow for novel experimental approaches, and more than 100 physicists are eagerly waiting for the first proton reactions in their detectors