Science.gov

Sample records for active cooling devices

  1. Platelet actively cooled thermal management devices

    NASA Astrophysics Data System (ADS)

    Mueggenburg, H. H.; Hidahl, J. W.; Kessler, E. L.; Rousar, D. C.

    1992-07-01

    An overview of 28 years of actively-cooled platelet thermal management devices design and development history is presented. Platelet devices are created by bonding together thin metal sheets (platelets) which contain chemically-etched coolant pasages. The bonding process produces an intricate and precise matrix of coolant passages and structural walls contained within a monolithic structure. Thirteen specific applications for platelet thermal management devices are described. These devices are cooled using convective, film, and transpiration cooling techniques. Platelet thermal management devices have been fabricated from a variety of metals, cooled with a variety of fluids, and operated at heat fluxes up to 200 Btu/sq in.-sec.

  2. Cooling device

    SciTech Connect

    Teske, L.

    1984-02-21

    A cooling device is claimed for coal dust comprising a housing, a motor-driven conveyor system therein to transport the coal dust over coolable trays in the housing and conveyor-wheel arms of spiral curvature for moving the coal dust from one or more inlets to one or more outlets via a series of communicating passages in the trays over which the conveyor-wheel arms pass under actuation of a hydraulic motor mounted above the housing and driving a vertical shaft, to which the conveyor-wheel arms are attached, extending centrally downwardly through the housing.

  3. MEMS Device Being Developed for Active Cooling and Temperature Control

    NASA Technical Reports Server (NTRS)

    Moran, Matthew E.

    2001-01-01

    High-capacity cooling options remain limited for many small-scale applications such as microelectronic components, miniature sensors, and microsystems. A microelectromechanical system (MEMS) is currently under development at the NASA Glenn Research Center to meet this need. It uses a thermodynamic cycle to provide cooling or heating directly to a thermally loaded surface. The device can be used strictly in the cooling mode, or it can be switched between cooling and heating modes in milliseconds for precise temperature control. Fabrication and assembly are accomplished by wet etching and wafer bonding 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 and limited failure modes, and minimal induced vibration.

  4. Evaporative Cooling Membrane Device

    NASA Technical Reports Server (NTRS)

    Lomax, Curtis (Inventor); Moskito, John (Inventor)

    1999-01-01

    An evaporative cooling membrane device is disclosed having a flat or pleated plate housing with an enclosed bottom and an exposed top that is covered with at least one sheet of hydrophobic porous material having a thin thickness so as to serve as a membrane. The hydrophobic porous material has pores with predetermined dimensions so as to resist any fluid in its liquid state from passing therethrough but to allow passage of the fluid in its vapor state, thereby, causing the evaporation of the fluid and the cooling of the remaining fluid. The fluid has a predetermined flow rate. The evaporative cooling membrane device has a channel which is sized in cooperation with the predetermined flow rate of the fluid so as to produce laminar flow therein. The evaporative cooling membrane device provides for the convenient control of the evaporation rates of the circulating fluid by adjusting the flow rates of the laminar flowing fluid.

  5. System and method of active vibration control for an electro-mechanically cooled device

    DOEpatents

    Lavietes, Anthony D.; Mauger, Joseph; Anderson, Eric H.

    2000-01-01

    A system and method of active vibration control of an electro-mechanically cooled device is disclosed. A cryogenic cooling system is located within an environment. The cooling system is characterized by a vibration transfer function, which requires vibration transfer function coefficients. A vibration controller generates the vibration transfer function coefficients in response to various triggering events. The environments may differ by mounting apparatus, by proximity to vibration generating devices, or by temperature. The triggering event may be powering on the cooling system, reaching an operating temperature, or a reset action. A counterbalance responds to a drive signal generated by the vibration controller, based on the vibration signal and the vibration transfer function, which adjusts vibrations. The method first places a cryogenic cooling system within a first environment and then generates a first set of vibration transfer function coefficients, for a vibration transfer function of the cooling system. Next, the cryogenic cooling system is placed within a second environment and a second set of vibration transfer function coefficients are generated. Then, a counterbalance is driven, based on the vibration transfer function, to reduce vibrations received by a vibration sensitive element.

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

    NASA Technical Reports Server (NTRS)

    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.

  7. Cooling Devices in Laser therapy

    PubMed Central

    Das, Anupam; Sarda, Aarti; De, Abhishek

    2016-01-01

    Cooling devices and methods are now integrated into most laser systems, with a view to protecting the epidermis, reducing pain and erythema and improving the efficacy of laser. On the basis of method employed, it can be divided into contact cooling and non-contact cooling. With respect to timing of irradiation of laser, the nomenclatures include pre-cooling, parallel cooling and post-cooling. The choice of the cooling device is dictated by the laser device, the physician's personal choice with respect to user-friendliness, comfort of the patient, the price and maintenance costs of the device. We hereby briefly review the various techniques of cooling, employed in laser practice. PMID:28163450

  8. Comparison of active cooling devices to passive cooling for rehabilitation of firefighters performing exercise in thermal protective clothing: A report from the Fireground Rehab Evaluation (FIRE) trial

    PubMed Central

    Hostler, David; Reis, Steven E; Bednez, James C; Kerin, Sarah; Suyama, Joe

    2010-01-01

    Background Thermal protective clothing (TPC) worn by firefighters provides considerable protection from the external environment during structural fire suppression. However, TPC is associated with physiological derangements that may have adverse cardiovascular consequences. These derangements should be treated during on-scene rehabilitation periods. Objective The present study examined heart rate and core temperature responses during the application of four active cooling devices, currently being marketed to the fire service for on-scene rehab, and compared them to passive cooling in a moderate temperature (approximately 24°C) and to an infusion of cold (4°C) saline. Methods Subjects exercised in TPC in a heated room. Following an initial exercise period (BOUT 1) the subjects exited the room, removed TPC, and for 20 minutes cooled passively at room temperature, received an infusion of cold normal saline, or were cooled by one of four devices (fan, forearm immersion in water, hand cooling, water perfused cooling vest). After cooling, subjects donned TPC and entered the heated room for another 50-minute exercise period (BOUT 2). Results Subjects were not able to fully recover core temperature during a 20-minute rehab period when provided rehydration and the opportunity to completely remove TPC. Exercise duration was shorter during BOUT 2 when compared to BOUT 1 but did not differ by cooling intervention. The overall magnitude and rate of cooling and heart rate recovery did not differ by intervention. Conclusions No clear advantage was identified when active cooling devices and cold intravenous saline were compared to passive cooling in a moderate temperature after treadmill exercise in TPC. PMID:20397868

  9. Electronic cooling using thermoelectric devices

    SciTech Connect

    Zebarjadi, M.

    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.

  10. Elastocaloric cooling: Stretch to actively cool

    NASA Astrophysics Data System (ADS)

    Ossmer, Hinnerk; Kohl, Manfred

    2016-10-01

    The elastocaloric effect can be exploited in solid-state cooling technologies as an alternative to conventional vapour compression. Now, an elastocaloric device based on the concept of active regeneration achieves a temperature lift of 15.3 K and efficiencies competitive with other caloric-based approaches.

  11. Theoretical limits on brain cooling by external head cooling devices

    PubMed Central

    Sukstanskii, A. L.; Yablonskiy, D. A.

    2007-01-01

    Numerous experimental studies have demonstrated that mild hypothermia is a rather promising therapy for acute brain injury in neonates. Because measurement of the resultant cooling of human brain in vivo is beyond current technology, an understanding of physical factors limiting the possible brain cooling would be a substantial achievement. Herein brain cooling by external head cooling devices is studied within the framework of an analytical model of temperature distribution in the brain. Theoretical limits on brain hypothermia induced by such devices are established. Analytical expressions are obtained that allow evaluation of changes in brain temperature under the influence of measurable input parameters. We show that a mild hypothermia can be successfully induced in neonates only if two necessary conditions are fulfilled: sufficiently low cerebral blood flow and sufficiently high value of the heat transfer coefficient describing the heat exchange between the head surface and a cooling device. PMID:17429678

  12. Polymer-based electrocaloric cooling devices

    DOEpatents

    Zhang, Qiming; Lu, Sheng-Guo; Li, Xinyu; Gorny, Lee; Cheng, Jiping; Neese, Bret P; Chu, Baojin

    2014-10-28

    Cooling devices (i.e., refrigerators or heat pumps) based on polymers which exhibit a temperature change upon application or removal of an electrical field or voltage, (e.g., fluoropolymers or crosslinked fluoropolymers that exhibit electrocaloric effect).

  13. Classification of electrocaloric cooling device types

    NASA Astrophysics Data System (ADS)

    Blumenthal, P.; Raatz, A.

    2016-07-01

    The research on the electrocaloric effect (ECE), the materials and their application has significantly increased in the last years, which resulted in several different concepts and demonstrators of electrocaloric (EC) cooling devices. The aim of this paper is to give a systematic overview of possible design concepts of EC cooling devices and to provide a method for their classification. Nine different device types could be distinguished. Each device type is being specified according to function principle, characteristic properties, technical challenges and technical readiness level. This classification and state of the art reveal areas requiring deeper research and can help researchers and engineers to select appropriate concepts for further investigation, improvement and application.

  14. Microgravity experiments on boiling and applications: research activity of advanced high heat flux cooling technology for electronic devices in Japan.

    PubMed

    Suzuki, Koichi; Kawamura, Hiroshi

    2004-11-01

    Research and development on advanced high heat flux cooling technology for electronic devices has been carried out as the Project of Fundamental Technology Development for Energy Conservation, promoted by the New Energy and Industrial Technology Development Organization of Japan (NEDO). Based on the microgravity experiments on boiling heat transfer, the following useful results have obtained for the cooling of electronic devices. In subcooled flow boiling in a small channel, heat flux increases considerably more than the ordinary critical heat flux with microbubble emission in transition boiling, and dry out of the heating surface is disturbed. Successful enhancement of heat transfer is achieved by a capillary effect from grooved surface dual subchannels on the liquid supply. The critical heat flux increases 30-40 percent more than for ordinary subchannels. A self-wetting mechanism has been proposed, following investigation of bubble behavior in pool boiling of binary mixtures under microgravity. Ideas and a new concept have been proposed for the design of future cooling system in power electronics.

  15. Personal cooling air filtering device

    DOEpatents

    Klett, James [Knoxville, TN; Conway, Bret [Denver, NC

    2002-08-13

    A temperature modification system for modifying the temperature of fluids includes at least one thermally conductive carbon foam element, the carbon foam element having at least one flow channel for the passage of fluids. At least one temperature modification device is provided, the temperature modification device thermally connected to the carbon foam element and adapted to modify the temperature of the carbon foam to modify the temperature of fluids flowing through the flow channels. Thermoelectric and/or thermoionic elements can preferably be used as the temperature modification device. A method for the reversible temperature modification of fluids includes the steps of providing a temperature modification system including at least one thermally conductive carbon foam element having flow channels and at least one temperature modification device, and flowing a fluid through the flow channels.

  16. Thermoelectric Devices Cool, Power Electronics

    NASA Technical Reports Server (NTRS)

    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.

  17. Mechano-caloric cooling device

    NASA Technical Reports Server (NTRS)

    Frederking, T. H. K.; Luna, Jack; Abbassi, P.; Carandang, R. M.

    1989-01-01

    The mechano-caloric effect is potentially useful in the He II temperature range. Aside from demonstration work, little quantification effort appears to have been known since other refrigeration possibilities have been available for some time. Successful He II use-related system examples are as follows: in space, the utilization of the latent heat of vaporization has been quite successful in vapor-liquid phase separation (VLPS) in conjunction with thermomechanical force application in plugs. In magnet cooling systems, the possibility of using the mechano-caloric cooling effect in conjunction with thermo-mechanical circulation pump schemes, has been assessed (but not quantified yet to the extent desirable). A third example is quoted in conjunction with superfluid wind tunnel studies and liquid helium tow tank for surface vessels respectively. In all of these (partially future) R and D areas, the question of refrigerator effectiveness using the mechano-caloric effect appears to be relevant, possibly in conjunction with questions of reliability and simplicity. The present work is concerned with quantification of phenomena including simplified thermodynamic cycle calculations.

  18. Self Cooling/Heating Devices

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A NASA RTTC assisted International Thermal Packaging (ITP) in the identification of a NASA-developed synthetic polymer that can absorb 1,000 times its weight in water. The desiccant was used in the manufacture of a self-chilling can, a major innovation for packaging food and beverages. The refrigeration device is a small cylinder, fully incorporated into the can. When used in beverage containers, the top of the can is popped, the internal carbonization pressure is relieved, and the self-chilling reaction is induced. Company product line has been expanded to include two related products, and several licensing agreements have been signed.

  19. Experimental evaluation of cooling efficiency of the high performance cooling device

    NASA Astrophysics Data System (ADS)

    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.

  20. Liquid cooling system for the vibro-tactile threshold device.

    PubMed

    Parsons, Erin M; Redd, Christian; Gandhi, Minu S; Tuckett, Robert P; Bamberg, Stacy J Morris

    2011-01-01

    Vibrotactile threshold testing has been used to investigate activation of human somatosensory pathways. A portable vibrotactile threshold testing device called the Vibrotactile Threshold Evaluator for the Workplace (VTEW) was designed for screening of carpal tunnel syndrome in the workplace, and initially contained a small fan for cooling. During subject testing, the device is operated intermittently, which causes the linear actuator to warm the tactile probe. The probe causes discomfort for some subjects. During testing, the probe heated to 42 °C within 90 seconds of continuous operation. A liquid cooling system was implemented to dissipate heat from the probe. The liquid cooling system maintains a steady state temperature of 36 °C for continuous actuation of the probe. The liquid cooling system is capable of maintaining a safe operating temperature, without adding erroneous vibrations to the device. However, the cooling system deters the portability of the device. Further research will investigate how to make the liquid cooling system portable and implements vibrotactile threshold testing in the workplace to quickly evaluate whether or not a person has early symptoms of carpal tunnel syndrome.

  1. Cooling of superconducting devices by liquid storage and refrigeration unit

    DOEpatents

    Laskaris, Evangelos Trifon; Urbahn, John Arthur; Steinbach, Albert Eugene

    2013-08-20

    A system is disclosed for cooling superconducting devices. The system includes a cryogen cooling system configured to be coupled to the superconducting device and to supply cryogen to the device. The system also includes a cryogen storage system configured to supply cryogen to the device. The system further includes flow control valving configured to selectively isolate the cryogen cooling system from the device, thereby directing a flow of cryogen to the device from the cryogen storage system.

  2. Two-Phase Cooling Method Using R134a Refrigerant to Cool Power Electronic Devices

    SciTech Connect

    Lowe, Kirk T; Tolbert, Leon M; Ayers, Curtis William; Ozpineci, Burak; Campbell, Jeremy B

    2007-01-01

    This paper presents a two-phase cooling method using R134a refrigerant to dissipate the heat energy (loss) generated by power electronics (PE) such as those associated with rectifiers, converters, and inverters for a specific application in hybrid-electric vehicles (HEVs). The cooling method involves submerging PE devices in an R134a bath, which limits the junction temperature of PE devices while conserving weight and volume of the heat sink without sacrificing equipment reliability. First, experimental tests that included an extended soak for more than 300 days were performed on a submerged IGBT and gate-controller card to study dielectric characteristics, deterioration effects, and heat flux capability of R134a. Results from these tests illustrate that R134a has high dielectric characteristics, no deterioration on electrical components, and a heat flux of 114 W/cm 2 for the experimental configuration. Second, experimental tests that included simultaneous operation with a mock automotive air-conditioner (A/C) system were performed on the same IGBT and gate controller card. Data extrapolation from these tests determined that a typical automotive A/C system has more than sufficient cooling capacity to cool a typical 30 kW traction inverter. Last, a discussion and simulation of active cooling of the IGBT junction layer with R134a refrigerant is given. This technique will drastically increase the forward current ratings and reliability of the PE device

  3. Integrated cooling devices in silicon technology

    NASA Astrophysics Data System (ADS)

    Perret, C.; Avenas, Y.; Gillot, Ch.; Boussey, J.; Schaeffer, Ch.

    2002-05-01

    Silicon technology has become a good alternative to copper for the elaboration of efficient cooling devices required in power electronics domain. Owing to its high degree of miniaturization, it is expected to provide suitable microchannels and other inlets holes that were not achievable by copper micromachining. Besides, the use of silicon technology provides a variety of bare materials (silicon dioxide, silicon nitride, silicide, etc.) which may be either insulator or conductive, with a good or bad thermal conductivity. This large choice makes it possible to built up rather complex multilayer devices with mechanical properties good enough in comparison with hybrid copper technology heat sinks. Nevertheless, the use of silicon technology, where the microchannel width may reach few tens of microns, raises fundamental features concerning the fluid displacement within such small sections. More precisely, fundamental fluid mechanics studies have to be conducted out in order to get an accurate description of the fluid boundary layers and to provide basic data on the exchange mechanisms occurring at these surfaces. In this paper, we review the operation principles of both single- and double-phase heat exchange devices elaborated in silicon technology. Forced-convection heat sinks as well as integrated micro heat pipes are analyzed. An analytical approach is adopted to evaluate their total thermal resistances as a function of several geometrical parameters. Numerical simulations are then used in order to assess the accuracy of the analytical approach and to evaluate the impact of the fluidic aspects on the whole performance. The optimum devices are then conceived thanks to an appropriate optimization procedure taken into account the several experimental constraints. Reference values of similar copper devices are reminded and the advantages of the silicon integrated approach are highlighted.

  4. Cooling devices and methods for use with electric submersible pumps

    SciTech Connect

    Jankowski, Todd A; Hill, Dallas D

    2014-12-02

    Cooling devices for use with electric submersible pump motors include a refrigerator attached to the end of the electric submersible pump motor with the evaporator heat exchanger accepting all or a portion of the heat load from the motor. The cooling device can be a self-contained bolt-on unit, so that minimal design changes to existing motors are required.

  5. Cooling devices and methods for use with electric submersible pumps

    SciTech Connect

    Jankowski, Todd A.; Hill, Dallas D.

    2016-07-19

    Cooling devices for use with electric submersible pump motors include a refrigerator attached to the end of the electric submersible pump motor with the evaporator heat exchanger accepting all or a portion of the heat load from the motor. The cooling device can be a self-contained bolt-on unit, so that minimal design changes to existing motors are required.

  6. Passive containment cooling water distribution device

    DOEpatents

    Conway, Lawrence E.; Fanto, Susan V.

    1994-01-01

    A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using a series of radial guide elements and cascading weir boxes to collect and then distribute the cooling water into a series of distribution areas through a plurality of cascading weirs. The cooling water is then uniformly distributed over the curved surface by a plurality of weir notches in the face plate of the weir box.

  7. Active feedback cooling of massive electromechanical quartz resonators

    SciTech Connect

    Jahng, Junghoon; Lee, Manhee; Stambaugh, Corey; Bak, Wan; Jhe, Wonho

    2011-08-15

    We present a general active feedback cooling scheme for massive electromechanical quartz resonators. We cool down two kinds of macrosized quartz tuning forks and find several characteristic constants for this massive quartz-resonator feedback cooling, in good agreement with theoretical calculations. When combined with conventional cryogenic techniques and low-noise devices, one may reach the quantum sensitivity for macroscopic sensors. This may be useful for high sensitivity measurements and for quantum information studies.

  8. Electric drive systems including smoothing capacitor cooling devices and systems

    DOEpatents

    Dede, Ercan Mehmet; Zhou, Feng

    2017-02-28

    An electric drive system includes a smoothing capacitor including at least one terminal, a bus bar electrically coupled to the at least one terminal, a thermoelectric device including a first side and a second side positioned opposite the first side, where the first side is thermally coupled to at least one of the at least one terminal and the bus bar, and a cooling element thermally coupled to the second side of the thermoelectric device, where the cooling element dissipates heat from the thermoelectric device.

  9. Active cleaning technique device

    NASA Technical Reports Server (NTRS)

    Shannon, R. L.; Gillette, R. B.

    1973-01-01

    The objective of this program was to develop a laboratory demonstration model of an active cleaning technique (ACT) device. The principle of this device is based primarily on the technique for removing contaminants from optical surfaces. This active cleaning technique involves exposing contaminated surfaces to a plasma containing atomic oxygen or combinations of other reactive gases. The ACT device laboratory demonstration model incorporates, in addition to plasma cleaning, the means to operate the device as an ion source for sputtering experiments. The overall ACT device includes a plasma generation tube, an ion accelerator, a gas supply system, a RF power supply and a high voltage dc power supply.

  10. Performance Estimation of Silicon-Based Self-Cooling Device

    NASA Astrophysics Data System (ADS)

    Fukuda, Shinji; Sabi, Yuichi; Kawahara, Toshio; Yamaguchi, Satarou

    2013-05-01

    Since self-cooling devices were first proposed, several materials have been tested for their suitability to be used in them. A self-cooling device requires a high Seebeck coefficient, a low electrical resistivity, and a high thermal conductivity. Here, we report experimental results for single-crystal silicon doped with boron. Samples were fabricated with carrier densities in the range of 2.0×1015 to 1.6×1019 cm-3, and their Seebeck coefficient and electrical resistivity were measured. Silicon with a carrier density of 1.6×1019 cm-3 has a power factor of 4.8×10-3 W/(K2.m) at room temperature. The cooling capability of a self-cooling device was estimated using a one-dimensional model. The results suggest that a self-cooling device based on silicon with a high carrier density can have a higher heat removal performance than a conventional silicon power device of the same size.

  11. Cooling Concepts for High Power Density Magnetic Devices

    NASA Astrophysics Data System (ADS)

    Biela, Juergen; Kolar, Johann W.

    In the area or power electronics there is a general trend to higher power densities. In order to increase the power density the systems must be designed optimally concerning topology, semiconductor selection, etc. and the volume of the components must be decreased. The decreasing volume comes along with a reduced surface for cooling. Consequently, new cooling methods are required. In the paper an indirect air cooling system for magnetic devices which combines the transformer with a heat sink and a heat transfer component is presented. Moreover, an analytic approach for calculating the temperature distribution is derived and validated by measurements. Based on these equations a transformer with an indirect air cooling system is designed for a 10kW telecom power supply.

  12. 76 FR 6551 - Medical Devices; General and Plastic Surgery Devices; Classification of Contact Cooling System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-07

    ... Devices; Classification of Contact Cooling System for Aesthetic Use AGENCY: Food and Drug Administration, HHS. ACTION: Final rule. SUMMARY: The Food and Drug Administration (FDA) is classifying the contact... Controls Guidance Document: Contact Cooling System for Aesthetic Use.'' The Agency is classifying...

  13. Testing Thermal Properties of the Cooling Device with Heat Pipes

    NASA Astrophysics Data System (ADS)

    Nemec, P.; Čaja, A.; Malcho, M.

    2013-04-01

    Paper deal about testing of device with heat pipes and about research alternative possible applications of heat pipes and potential improvements in purpose effective heat sink from power switches of device. This device is used in various static and moveable applications. Testing device is part of control unit in rail vehicle. The amount of heat produced by power switches depend from working conditions of static converter. Great impact on heat sink has, how as season also this if the vehicle is moving or don't moving. If the vehicle is moving the heat transfer form energy converter to surrounding is caused by forced convection of air flow around device. But the critical conditions occur if the vehicle doesn't move, because the application of this cooling device is based on natural convection. The study deal solution of the problem heat transfer from energy converter to surrounding by natural convection.

  14. Cooling device featuring thermoelectric and diamond materials for temperature control of heat-dissipating devices

    NASA Technical Reports Server (NTRS)

    Vandersande, Ian W. (Inventor); Ewell, Richard (Inventor); Fleurial, Jean-Pierre (Inventor); Lyon, Hylan B. (Inventor)

    1998-01-01

    A cooling device for lowering the temperature of a heat-dissipating device. The cooling device includes a heat-conducting substrate (composed, e.g., of diamond or another high thermal conductivity material) disposed in thermal contact with the heat-dissipating device. During operation, heat flows from the heat-dissipating device into the heat-conducting substrate, where it is spread out over a relatively large area. A thermoelectric cooling material (e.g., a Bi.sub.2 Te.sub.3 -based film or other thermoelectric material) is placed in thermal contact with the heat-conducting substrate. Application of electrical power to the thermoelectric material drives the thermoelectric material to pump heat into a second heat-conducting substrate which, in turn, is attached to a heat sink.

  15. Heat transfer to the adsorbent in solar adsorption cooling device

    NASA Astrophysics Data System (ADS)

    Pilat, Peter; Patsch, Marek; Papucik, Stefan; Vantuch, Martin

    2014-08-01

    The article deals with design and construction of solar adsorption cooling device and with heat transfer problem in adsorber. The most important part of adsorption cooling system is adsorber/desorber containing adsorbent. Zeolith (adsorbent) type was chosen for its high adsorption capacity, like a coolant was used water. In adsorber/desorber occur, at heating of adsorbent, to heat transfer from heat change medium to the adsorbent. The time required for heating of adsorber filling is very important, because on it depend flexibility of cooling system. Zeolith has a large thermal resistance, therefore it had to be adapted the design and construction of adsorber. As the best shows the tube type of adsorber with double coat construction. By this construction is ensured thin layer of adsorbent and heating is quick in all volume of adsorbent. The process of heat transfer was experimentally measured, but for comparison simulated in ANSYS, too.

  16. Active skin cooling in conjunction with laser dermatologic surgery.

    PubMed

    Nelson, J S; Majaron, B; Kelly, K M

    2000-12-01

    The clinical objective in the laser treatment of patients with specific dermatoses is to maximize thermal damage to the target chromophore while minimizing injury to the normal skin. Unfortunately, for some lesions, the threshold incident light dosage for epidermal injury can be very close to the threshold for permanent removal of the target chromophore, thus precluding the use of higher light dosages. An important method of overcoming the aforementioned problem is to selectively cool the most superficial layers of the skin. Although melanin absorption will result in heat production during laser exposure, cooling the epidermis can prevent its temperature elevation from exceeding the threshold for thermal injury. Spatially selective cooling can be achieved by active cooling using a cryogen spray or cold sapphire contact handpieces. These devices promote rapid and spatially selective epidermal cooling to low temperatures without affecting the target chromophore temperature before the laser pulse is delivered. Cooling has become an Integral part in the emerging discipline of laser dermatologic surgery. Attend almost any academic dermatology conference and you are likely to find many lectures that relate to cooling during dermatologic laser surgery. Although cooling in conjunction with laser therapy has become the clinical standard for many laser procedures, considerable controversy surrounds this methodology. We present herewith an overview of currently used techniques for active cooling of human skin and explore their advantages and disadvantages in relationship to specific dermatoses amenable to laser therapy.

  17. High power electronic devices cooling at minimum ventilation power

    NASA Astrophysics Data System (ADS)

    Fabbri, Giampietro

    2008-01-01

    In the present work, the cooling of a high power electronic device is studied. The device is in contact with a heat dissipator crossed by air. The air motion through the dissipator is forced by a fan whose supplied power is to be minimized. A finite element dynamic model of the dissipator is firstly created, taking geometrical and physical properties into account as well as steady state experimental data. A simplified model is then obtained, which reproduces the time pattern of the maximum dissipator temperature as a response of the thermal flux removed from the electronic device and the mass flow rate of the air. Afterwards, the simplified model is utilized to build a control system which allows the electronic device to be correctly cooled at minimum air ventilation power during transition to steady states. Genetic algorithms are used to find the parameters of the finite element model and of the control system. Some functioning conditions of the electronic device are lastly considered and discussed.

  18. External Cooling Coupled to Reduced Extremity Pressure Device

    NASA Technical Reports Server (NTRS)

    Kuznetz, Lawrence H.

    2011-01-01

    Although suited astronauts are currently cooled with a Liquid Cooled Ventilation Garment (LCVG), which can remove up to 85 percent of body heat, their effectiveness is limited because cooling must penetrate layers of skin, muscle, fat, bone, and tissue to reach the bloodstream, where its effect is prominent. Vasoconstriction further reduces the effectiveness by limiting arterial flow when exposed to cold (the frostbite response), resulting in a time constant on the order of 20 minutes from application to maximum effect. This delay can be crucial in severe exposure to hypo- or hyper-thermic conditions, compromising homeostasis. The purpose of this innovation is to provide a lightweight, effective means of delivering heat or cold from an external source directly to the bloodstream. The effectiveness of this ECCREP (External Cooling Coupled to Reduced Extremity Pressure) device is based on not having to penetrate layers of skin, muscle, fat, and tissue, thereby avoiding the thermal lag associated with their mass and heat capacity. This is accomplished by means of an outer boot operating at a slightly reduced pressure than the rest of the body, combined with an inner boot cooled or heated by an external source via water or chemicals. Heat transfer from the external source to the foot takes place by means of circulating water or flexible heat pipes.

  19. On-chip magnetic cooling of a nanoelectronic device

    PubMed Central

    Bradley, D. I.; Guénault, A. M.; Gunnarsson, D.; Haley, R. P.; Holt, S.; Jones, A. T.; Pashkin, Yu. A.; Penttilä, J.; Prance, J. R.; Prunnila, M.; Roschier, L.

    2017-01-01

    We demonstrate significant cooling of electrons in a nanostructure below 10 mK by demagnetisation of thin-film copper on a silicon chip. Our approach overcomes the typical bottleneck of weak electron-phonon scattering by coupling the electrons directly to a bath of refrigerated nuclei, rather than cooling via phonons in the host lattice. Consequently, weak electron-phonon scattering becomes an advant- age. It allows the electrons to be cooled for an experimentally useful period of time to temperatures colder than the dilution refrigerator platform, the incoming electrical connections, and the host lattice. There are efforts worldwide to reach sub-millikelvin electron temperatures in nanostructures to study coherent electronic phenomena and improve the operation of nanoelectronic devices. On-chip magnetic cooling is a promising approach to meet this challenge. The method can be used to reach low, local electron temperatures in other nanostructures, obviating the need to adapt traditional, large demagnetisation stages. We demonstrate the technique by applying it to a nanoelectronic primary thermometer that measures its internal electron temperature. Using an optimised demagnetisation process, we demonstrate cooling of the on-chip electrons from 9 mK to below 5 mK for over 1000 seconds. PMID:28374845

  20. Solid state lighting devices and methods with rotary cooling structures

    DOEpatents

    Koplow, Jeffrey P.

    2017-03-21

    Solid state lighting devices and methods for heat dissipation with rotary cooling structures are described. An example solid state lighting device includes a solid state light source, a rotating heat transfer structure in thermal contact with the solid state light source, and a mounting assembly having a stationary portion. The mounting assembly may be rotatably coupled to the heat transfer structure such that at least a portion of the mounting assembly remains stationary while the heat transfer structure is rotating. Examples of methods for dissipating heat from electrical devices, such as solid state lighting sources are also described. Heat dissipation methods may include providing electrical power to a solid state light source mounted to and in thermal contact with a heat transfer structure, and rotating the heat transfer structure through a surrounding medium.

  1. A chip scale electrocaloric effect based cooling device

    NASA Astrophysics Data System (ADS)

    Gu, Haiming; Qian, Xiaoshi; Li, Xinyu; Craven, Brent; Zhu, Wenyi; Cheng, Ailan; Yao, S. C.; Zhang, Q. M.

    2013-03-01

    The recent finding of large electrocaloric effect in several ferroelectric polymers creates unique opportunity for developing compact size solid state cooling cycles beyond the traditional mechanical vapor compression cycles. Here, we show that, by employing regeneration process with solid state regenerators, a chip scale Electrocaloric Oscillatory Refrigeration (ECOR) can be realized. A prototype ECOR is fabricated and characterized. More than 6 K temperature span is obtained near room temperature between the hot and cold sides of a 2 cm long device. Finite volume simulation validates the test results and shows the potential high performance of the ECOR.

  2. Liquid Acquisition Device Testing with Sub-Cooled Liquid Oxygen

    NASA Technical Reports Server (NTRS)

    Jurns, John M.; McQuillen, John B.

    2008-01-01

    When transferring propellant in space, it is most efficient to transfer single phase liquid from a propellant tank to an engine. In earth s gravity field or under acceleration, propellant transfer is fairly simple. However, in low gravity, withdrawing single-phase fluid becomes a challenge. A variety of propellant management devices (PMD) are used to ensure single-phase flow. One type of PMD, a liquid acquisition device (LAD) takes advantage of capillary flow and surface tension to acquire liquid. Previous experimental test programs conducted at NASA have collected LAD data for a number of cryogenic fluids, including: liquid nitrogen (LN2), liquid oxygen (LOX), liquid hydrogen (LH2), and liquid methane (LCH4). The present work reports on additional testing with sub-cooled LOX as part of NASA s continuing cryogenic LAD development program. Test results extend the range of LOX fluid conditions examined, and provide insight into factors affecting predicting LAD bubble point pressures.

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

    NASA Technical Reports Server (NTRS)

    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. Silicon active photonic devices

    NASA Astrophysics Data System (ADS)

    Dimitropoulos, Dimitrios

    Active photonic devices utilizing the optical nonlinearities of silicon have emerged in the last 5 years and the effort for commercial photonic devices in the material that has been the workhorse of electronics has been building up since. This dissertation presents the theory for some of these devices. We are concerned herein with CW lasers, amplifiers and wavelength converters that are based on the Raman effect. There have already been cursory experimental demonstrations of these devices and some of their limitations are already apparent. Most of the limitations observed are because of the appearance of effects that are competing with stimulated Raman scattering. Under the high optical powers that are necessary for the Raman effect (tens to hundrends of mW's) the process of optical two-photon (TPA) absorption occurs. The absorption of optical power that it causes itself is weak but in the process electrons and holes are generated which can further absorb light through the free-carrier absorption effect (FCA). The effective "lifetime" that these carriers have determines the magnitude of the FCA loss. We present a model for the carrier lifetime in Silicon-On-Insulator (SOI) waveguides and numerical simulations to understand how this critical parameter varies and how it can be controlled. A p-i-n junction built along SOI waveguides can help achieve lifetime of the order of 20--100 ps but the price one has to pay is on-chip electrical power consumption on the order of 100's of mWs. We model CW Raman lasers and we find that the carrier lifetime reduces the output power. If the carrier lifetime exceeds a certain "critical" value optical losses become overwhelming and lasing is impossible. As we show, in amplifiers, the nonlinear loss does not only result in diminished gain, but also in a higher noise figure. Finally the effect of Coherent anti-Stokes Raman scattering (CARS) is examined. The effect is important because with a pump frequency at 1434nm coherent power

  5. Axially Tapered And Bilayer Microchannels For Evaporative Cooling Devices

    DOEpatents

    Nilson, Robert; Griffiths, Stewart

    2005-10-04

    The invention consists of an evaporative cooling device comprising one or more microchannels whose cross section is axially reduced to control the maximum capillary pressure differential between liquid and vapor phases. In one embodiment, the evaporation channels have a rectangular cross section that is reduced in width along a flow path. In another embodiment, channels of fixed width are patterned with an array of microfabricated post-like features such that the feature size and spacing are gradually reduced along the flow path. Other embodiments incorporate bilayer channels consisting of an upper cover plate having a pattern of slots or holes of axially decreasing size and a lower fluid flow layer having channel widths substantially greater than the characteristic microscale dimensions of the patterned cover plate. The small dimensions of the cover plate holes afford large capillary pressure differentials while the larger dimensions of the lower region reduce viscous flow resistance.

  6. Simulation of scalp cooling by external devices for prevention of chemotherapy-induced alopecia.

    PubMed

    Pliskow, Bradley; Mitra, Kunal; Kaya, Mehmet

    2016-02-01

    Hypothermia of the scalp tissue during chemotherapy treatment (scalp cooling) has been shown to reduce or prevent chemotherapy-induced hair loss. In this study, numerical models are developed to investigate the interaction between different types of external scalp cooling devices and the human scalp tissue. This work focuses on improving methods of modeling scalp cooling devices as it relates specifically to the prevention of chemotherapy-induced alopecia. First, the cooling power needed for any type of device to achieve therapeutic levels of scalp hypothermia is investigated. Subsequently, two types of scalp cooling devices are simulated: a pre-cooled/frozen cap design and a liquid-cooled cap design. For an average patient, simulations show that 38.5W of heat must be extracted from the scalp tissue for this therapy in order to cool the hair follicle to 22°C. In practice, the cooling power must be greater than this amount to account for thermal losses of the device. Simulations show that pre-cooled and liquid-cooled cap designs result in different tissue temperatures over the course of the procedure. However, it is the temperature of the coolant that largely determines the resulting tissue temperature. Simulations confirm that the thermal resistance of the hair/air layer has a large impact on the resulting tissue temperatures. The results should be correlated with experimental data as an effort to determine the optimal parameter choices for this model.

  7. Dimensionless Model of a Thermoelectric Cooling Device Operating at Real Heat Transfer Conditions: Maximum Cooling Capacity Mode

    NASA Astrophysics Data System (ADS)

    Melnikov, A. A.; Kostishin, V. G.; Alenkov, V. V.

    2016-09-01

    Real operating conditions of a thermoelectric cooling device are in the presence of thermal resistances between thermoelectric material and a heat medium or cooling object. They limit performance of a device and should be considered when modeling. Here we propose a dimensionless mathematical steady state model, which takes them into account. Analytical equations for dimensionless cooling capacity, voltage, and coefficient of performance (COP) depending on dimensionless current are given. For improved accuracy a device can be modeled with use of numerical or combined analytical-numerical methods. The results of modeling are in acceptable accordance with experimental results. The case of zero temperature difference between hot and cold heat mediums at which the maximum cooling capacity mode appears is considered in detail. Optimal device parameters for maximal cooling capacity, such as fraction of thermal conductance on the cold side y, fraction of current relative to maximal j' are estimated in range of 0.38-0.44 and 0.48-0.95, respectively, for dimensionless conductance K' = 5-100. Also, a method for determination of thermal resistances of a thermoelectric cooling system is proposed.

  8. Spray cooling characteristics of nanofluids for electronic power devices

    NASA Astrophysics Data System (ADS)

    Hsieh, Shou-Shing; Leu, Hsin-Yuan; Liu, Hao-Hsiang

    2015-03-01

    The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein. The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm. The effects of nanoparticle volume fraction and mass flow rate of the liquid on the surface heat flux, including critical heat flux (CHF), are explored. Both steady state and transient data are collected for the two-phase heat transfer coefficient, boiling curve/ cooling history, and the corresponding CHF. The heat transfer removal rate can reach up to 274 W/cm2 with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10-4 kg/cm2s.

  9. Spray cooling characteristics of nanofluids for electronic power devices.

    PubMed

    Hsieh, Shou-Shing; Leu, Hsin-Yuan; Liu, Hao-Hsiang

    2015-01-01

    The performance of a single spray for electronic power devices using deionized (DI) water and pure silver (Ag) particles as well as multi-walled carbon nanotube (MCNT) particles, respectively, is studied herein. The tests are performed with a flat horizontal heated surface using a nozzle diameter of 0.5 mm with a definite nozzle-to-target surface distance of 25 mm. The effects of nanoparticle volume fraction and mass flow rate of the liquid on the surface heat flux, including critical heat flux (CHF), are explored. Both steady state and transient data are collected for the two-phase heat transfer coefficient, boiling curve/ cooling history, and the corresponding CHF. The heat transfer removal rate can reach up to 274 W/cm(2) with the corresponding CHF enhancement ratio of 2.4 for the Ag/water nanofluids present at a volume fraction of 0.0075% with a low mass flux of 11.9 × 10(-4) kg/cm(2)s.

  10. PCM Passive Cooling System Containing Active Subsystems

    NASA Technical Reports Server (NTRS)

    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.

  11. Activation of a new cooling tower facility

    SciTech Connect

    Lansford, W.D.

    1986-01-01

    The activation of a completely new facility presents problems not found in modifications or additions to existing systems. Known baselines of previous operations provide some guidelines as to what is causing a particular problem. However, when a totally new, complex facility initially becomes operational, unfamiliar instrumentation, mechanical equipment, and unknown system idiosyncrasies, require careful analysis of each event to determine whether one is observing a symptom of pending disaster or a minor isolated occurrence of some subsystem. Careful planning and progressive introduction of related systems must be initiated, introducing operating personnel into the chain of events as early as possible. Personnel responsible for operation and maintenance should participate in the review of initial concepts and designs, to provide input based on systems experience. The cooling tower system described in this paper has gained recognition for dependability and consistency of operations since initially becoming operational. Instead of a once weekly activity, as originally anticipated, test units are now requesting cooling tower support for all test operations. During one five-month period, a total of 660 cooling tower operating hours were logged with one test support period of 78 non-stop hours recorded. The use of the cooling tower beyond original expectations is a compliment without comparison.

  12. Nano Peltier cooling device from geometric effects using a single graphene nanoribbon

    NASA Astrophysics Data System (ADS)

    Li, Wan-Ju; Yao, Dao-Xin; Carlson, Erica

    2012-02-01

    Based on the phenomenon of curvature-induced doping in graphene we propose a class of Peltier cooling devices, produced by geometrical effects, without gating. We show how a graphene nanoribbon laid on an array of curved nano cylinders can be used to create a targeted cooling device. Using theoretical calculations and experimental inputs, we predict that the cooling power of such a device can approach 1kW/cm^2, on par with the best known techniques using standard lithography methods. The structure proposed here helps pave the way toward designing graphene electronics which use geometry rather than gating to control devices.

  13. High quality actively cooled plasma facing components for fusion

    SciTech Connect

    Nygren, R.

    1993-12-31

    This paper interweaves some suggestions for developing actively-cooled PFCs (plasma facing components) for future fusion devices with supporting examples taken from the design, fabrication and operation of Tore Supra`s Phase III Outboard Pump Limiter (OPL). This actively-cooled midplane limiter, designed for heat and particle removal during long pulse operation, has been operated in essentially thermally steady state conditions. From experience with testing to identify braze flaws in the OPL, recommendations are made to analyze the impact of joining flaws on thermal-hydraulic performance of PFCs and to validate a method of inspection for such flaws early in the design development. Capability for extensive in-service monitoring of future PFCs is also recommended and the extensive calorimetry and IR thermography used to confirm and update safe operating limits for power handling of the OPL are reviewed.

  14. Cooling device for bradycardia based on Peltier element for accurate anastomosis of off-pump coronary artery bypass grafting.

    PubMed

    Kuniyoshi, Yukio; Koja, Kageharu; Miyagi, Kazufumi; Shimoji, Mituyoshi; Uezu, Tooru; Arakaki, Katuya; Yamashiro, Satoshi; Mabuni, Katuhito; Senaha, Shigenobu

    2002-10-01

    Upon introducing off-pump coronary artery bypass grafting (CABG), the indications for CABG were expanded to include patients who previously had no operative indications. For accurate anastomosis, various devices and methods have been developed. Bradycardia is easily induced by drug administration. However, this method of achieving bradycardia also has adverse effects on cardiac function. We have developed a new device to decrease the heart rate by regional cooling of the sino-atrial node. The new device is incorporated with Peltier's element, which uses an electric charge to create a temperature gradient on both of its surfaces. In terms of the cooling ability of this device, its cooling surface is chilled from 25 degrees C to 0 degrees C within 30 s. During in vivo animal experiments, this device has been shown to decrease the myocardial temperature around the sino-atrial node to 15 degrees C and suppress sino-atrial node activity, resulting in bradycardia to 60 beats/min level. In summary, the simple and easily applicable device for local cooling in combination with the application of diltiazem for effective heart rate reduction may be very helpful for the surgeon and may avoid disadvantages for critically ill patients.

  15. Method and apparatus of cryogenic cooling for high temperature superconductor devices

    DOEpatents

    Yuan, Xing; Mine, Susumu

    2005-02-15

    A method and apparatus for providing cryogenic cooling to HTS devices, in particular those that are used in high-voltage electric power applications. The method involves pressurizing liquid cryogen to above one atmospheric pressure to improve its dielectric strength, while sub-cooling the liquid cryogen to below its saturation temperature in order to improve the performance of the HTS components of the device. An apparatus utilizing such a cooling method consists of a vessel that contains a pressurized gaseous cryogen region and a sub-cooled liquid cryogen bath, a liquid cryogen heating coupled with a gaseous cryogen venting scheme to maintain the pressure of the cryogen to a value in a range that corresponds to optimum dielectric strength of the liquid cryogen, and a cooling system that maintains the liquid cryogen at a temperature below its boiling point to improve the performance of HTS materials used in the device.

  16. Activated-Carbon Sorbent With Integral Heat-Transfer Device

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Yavrouian, Andre

    1996-01-01

    Prototype adsorption device used, for example, in adsorption heat pump, to store natural gas to power automobile, or to separate components of fluid mixtures. Device includes activated carbon held together by binder and molded into finned heat-transfer device providing rapid heating or cooling to enable rapid adsorption or desorption of fluids. Concepts of design and fabrication of device equally valid for such other highly thermally conductive devices as copper-finned tubes, and for such other high-surface-area sorbents as zeolites or silicates.

  17. Temperature Regulator for Actively Cooled Structures

    NASA Technical Reports Server (NTRS)

    Blosser, Max (Inventor); Kelly, H. Neale (Inventor)

    1995-01-01

    In active cooling of a structure it is beneficial to use a plurality of passages for conducting coolant to various portions of the structure. Since most structures do not undergo isotropic thermal loads it is desirable to allow for variation in coolant flow to each area of the structure. The present invention allows for variable flow by a variation of the area of a portion of each of the coolant passages. Shape memory alloys and bi-material springs are used to produce passages that change flow area as a function of temperature.

  18. Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices

    DTIC Science & Technology

    2015-05-12

    nanofabrication to develop nanostructured thermoelectric (TE) materials for application in high-efficiency thermoelectric power generators and solid...Distribution Unlimited Final Report: Development of Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric...Thermoelectric Power Generation and Peltier Cooling Properties of Materials for Thermoelectric Cryocooling Devices Report Title The research

  19. Fuel cell crimp-resistant cooling device with internal coil

    DOEpatents

    Wittel, deceased, Charles F.

    1986-01-01

    A cooling assembly for fuel cells having a simplified construction whereby coolant is efficiently circulated through a conduit arranged in serpentine fashion in a channel within a member of such assembly. The channel is adapted to cradle a flexible, chemically inert, conformable conduit capable of manipulation into a variety of cooling patterns without crimping or otherwise restricting of coolant flow. The conduit, when assembled with the member, conforms into intimate contact with the member for good thermal conductivity. The conduit is non-corrodible and can be constructed as a single, manifold-free, continuous coolant passage means having only one inlet and one outlet. The conduit has an internal coil means which enables it to be bent in small radii without crimping.

  20. Termination of epileptiform activity by cooling in rat hippocampal slice epilepsy models.

    PubMed

    Motamedi, Gholam K; Salazar, Patricia; Smith, Eric L; Lesser, Ronald P; Webber, William R S; Ortinski, Pavel I; Vicini, Stefano; Rogawski, Michael A

    2006-08-01

    Cooling has been shown to terminate experimentally induced epileptiform activity in models of epilepsy without causing injury to the cooled brain, suggesting that cooling could represent an approach to seizure control in intractable focal epilepsies. Here we sought to determine the most effective way to apply cooling to abort spontaneous epileptiform discharges in in vitro brain slice models. We induced spontaneous epileptiform activity in rat brain slices by exposure to 4-aminopyridine (4-AP), 4-AP plus bicuculline, and Mg(2+)-free artificial CSF (aCSF) at 28-34 degrees C. Extracellular field recordings were made at hippocampal or neocortical sites. Slice temperature was reduced by perfusion with cold aCSF. Rapid cooling at rates of 2-5 degrees C/s was compared to cooling at slower rates of 0.1-1 degrees C/s. Cooling at both rates reversibly aborted epileptiform discharges in all three models and at all recording sites. With rapid cooling, small temperature drops were highly effective in terminating discharges, an effect that was sustained for as long as the reduced temperature level was maintained. In contrast, slow cooling required much larger temperature drops to inhibit discharges. With slow cooling, absolute temperature drops to 21-22 degrees C caused a 90% reduction in event frequency, but cooling to 14-15 degrees C was required to terminate discharges. We conclude that rapid cooling as effectively aborts discharges in in vitro epilepsy models as does slow cooling, but the magnitude of the temperature change required is less. Practical devices to inhibit seizure activity may only need to induce small temperature drops, if the cooling can be applied sufficiently rapidly.

  1. Active and passive cooling for concentrating photovoltaic arrays

    SciTech Connect

    Edenburn, M.W.

    1981-10-01

    Optimization, based on minimum energy cost, of active and passive cooling designs for point-focus Fresnel lens photovoltaic arrays and line-focus, parabolic-trough photovoltaic arrays is discussed, and the two types of cooling are compared. Passive cooling is more cost-effective for Fresnel lens arrays while the reverse is true for parabolic-trough arrays.

  2. Annual DOE Active Solar Heating and Cooling Contractors Review meeting

    NASA Astrophysics Data System (ADS)

    1981-09-01

    Ninety three project summaries dicussing the following aspects of active solar heating and cooling are presented: 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.

  3. Chromospheric Activity in Cool Stars: Open Questions

    NASA Astrophysics Data System (ADS)

    Schröder, K.-P.; Schmitt, J. H. M. M.

    2013-04-01

    Despite a wealth of observational insight into chromospheric physics obtained in the past decades, a number of fundamental questions remain to be answered. On some of them we seem to make progress, others are motivation for ongoing research: is there a well-defined “zero-point” of magnetic stellar activity, and by which heating processes is the basal chromospheric flux created? Or: how did the Sun look like during the Maunder Minimum, and when is the next one due? And are activity cycles of cool giants caused by a solar-type dynamo, despite a very different internal structure? What makes magnetic stellar activity be still (or again?) at work in such very evolved stars — should not all angular momentum have been consumed? To find some answers, the Hamburg Robotic Telescope, equipped with a high-resolution (20,000) spectrograph, will start regular operation at its final site in Guanajuato, central Mexico, this year (2012), in part to resume the legendary Mt. Wilson stellar activity monitoring project.

  4. Tunable nano Peltier cooling device from geometric effects using a single graphene nanoribbon

    NASA Astrophysics Data System (ADS)

    Li, Wan-Ju; Yao, Dao-Xin; Carlson, E. W.

    2014-08-01

    Based on the phenomenon of curvature-induced doping in graphene we propose a class of Peltier cooling devices, produced by geometrical effects, without gating. We show how a graphene nanoribbon laid on an array of curved nano cylinders can be used to create a targeted and tunable cooling device. Using two different approaches, the Nonequilibrium Green's Function (NEGF) method and experimental inputs, we predict that the cooling power of such a device can approach the order of kW/cm2, on par with the best known techniques using standard superlattice structures. The structure proposed here helps pave the way toward designing graphene electronics which use geometry rather than gating to control devices.

  5. System and method for cooling a super-conducting device

    DOEpatents

    Bray, James William; Steinbach, Albert Eugene; Dawson, Richard Nils; Laskaris, Evangelos Trifon; Huang, Xianrul

    2008-01-08

    A system and method for cooling a superconductive rotor coil. The system comprises a rotatable shaft coupled to the superconductive rotor coil. The rotatable shaft may comprise an axial passageway extending through the rotatable shaft and a first passageway extending through a wall of the rotatable shaft to the axial passageway. The axial passageway and the first passageway are operable to convey a cryogenic fluid to the superconductive rotor coil through the wall of the rotatable shaft. A cryogenic transfer coupling may be provided to supply cryogenic fluid to the first passageway.

  6. The Design of Actively Cooled Plasma-Facing Components

    NASA Astrophysics Data System (ADS)

    Scheerer, M.; Bolt, H.; Gervash, A.; Linke, J.; Smid, I.

    In future fusion devices, like in the stellarator Wendelstein 7-X, the target plates of the divertor will be exposed to heat loads up to power densities of 10 MW/m2 for 1000 s. For this purpose actively cooled target elements with an internal coolant flow return, made of 2-D CFC armor tiles brazed onto a two tube cooling structure were developed and manufactured at the Forschungszentrum Jülich. Individual bent- and coolant flow reversal elements were used to achieve a high flexibility in the shape of the target elements. A special brazing technology, using a thin layer of plasma-arc deposited titanium was used for the bonding of the cooling structure to the plasma facing armor (PFA). FEM-simulations of the thermal and mechanical behavior show that a detachment of about 25% of the bonded area between the copper tubes and the PFA can be tolerated, without exceeding the critical heat flux at 15 MW/m2 or a surface temperature of 1400°C at 10 MW/m2 by using twisted tape inserts with a twist ratio of 2 at a cooling water velocity of 10 m/s. Thermal cycling tests in an electron beam facility up to a power density level 10.5 MW/m2 show a very good behavior of parts of the target elements, which confirms the performance under fusion relevant conditions. Even defected parts in the bonding interface of the target elements, known from ultrasonic inspections before, show no change in the thermal performance under cycling, which confirms also the structural integrity of partly defected regions.

  7. Actively controlling coolant-cooled cold plate configuration

    DOEpatents

    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.

  8. Dual control active superconductive devices

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1993-07-20

    A superconducting active device has dual control inputs and is constructed such that the output of the device is effectively a linear mix of the two input signals. The device is formed of a film of superconducting material on a substrate and has two main conduction channels, each of which includes a weak link region. A first control line extends adjacent to the weak link region in the first channel and a second control line extends adjacent to the weak link region in the second channel. The current flowing from the first channel flows through an internal control line which is also adjacent to the weak link region of the second channel. The weak link regions comprise small links of superconductor, separated by voids, through which the current flows in each channel. Current passed through the control lines causes magnetic flux vortices which propagate across the weak link regions and control the resistance of these regions. The output of the device taken across the input to the main channels and the output of the second main channel and the internal control line will constitute essentially a linear mix of the two input signals imposed on the two control lines. The device is especially suited to microwave applications since it has very low input capacitance, and is well suited to being formed of high temperature superconducting materials since all of the structures may be formed coplanar with one another on a substrate.

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

    PubMed

    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.

  10. Active and passive cooling for concentrating photovoltaic arrays

    SciTech Connect

    Edenburn, M.W.

    1980-01-01

    The optimization, based on minimum energy cost, of active and passive cooling designs for point-focus Fresnel lens photovoltaic arrays and line-focus, parabolic-trough photovoltaic arrays are discussed, and the two types of cooling are compared. Passive cooling is more cost effective than active for Fresnel lens arrays while the reverse is true for parabolic trough arrays. The analysis produced several other conclusions of interest which are also discussed.

  11. Actively controlling coolant-cooled cold plate configuration

    SciTech Connect

    Chainer, Timothy J.; Parida, Pritish R.

    2015-07-28

    A method is provided to facilitate active control of thermal and fluid dynamic performance of a coolant-cooled cold plate. The method includes: monitoring a variable associated with at least one of the coolant-cooled cold plate or one or more electronic components being cooled by the cold plate; and dynamically varying, based on the monitored variable, a physical configuration of 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 one or more electronic components, 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 coolant-cooled cold plate, the positioning of which may be adjusted based on the monitored variable.

  12. Developing Electrocaloric (EC) Materials with Giant EC Response and Chip-Scale EC Cooling Devices

    NASA Astrophysics Data System (ADS)

    Zhang, Qiming

    2015-03-01

    The direct and efficient coupling between the electric signals and the elastic, thermal, optical and magnetic signals in ferroelectric based electroactive materials makes them attractive for exploiting a broad range of cross-coupling phenomena which have great promise for new device technologies. This talk will present the recent advances at Penn State in developing electrocaloric materials which may provide alternative cooling technology to replace the century old vapor compression cycle (VCC) based cooling which employs strong greenhouse gases as the refrigerants. Electrocaloric effect (ECE), which is the temperature and entropy change of insulating dielectric materials under electric fields, is attractive to realize efficient cooling devices. However, the relatively small ECE observed in dielectrics in the last century make it unimpressive for any practical applications. Experimental results on the ECE in the relaxor ferroelectric polymers and general theoretical considerations for achieving large ECE will be presented. This talk will also discuss considerations on and present recent works in using nanocomposites to further enhancing the ECE beyond the pure relaxor polymers, on the giant ECE in a class of dielectric liquid, and in bulk ferroelectric ceramics near the invariant critical point. The works related to developing the chip-scale EC cooling devices, exploiting the newly discovered large ECE in ferroelectric materials and featuring high cooling power density and high efficiency, will also be presented. This work has been supported by DoE BES and by ARO.

  13. Heat-driven liquid metal cooling device for the thermal management of a computer chip

    NASA Astrophysics Data System (ADS)

    Ma, Kun-Quan; Liu, Jing

    2007-08-01

    The tremendous heat generated in a computer chip or very large scale integrated circuit raises many challenging issues to be solved. Recently, liquid metal with a low melting point was established as the most conductive coolant for efficiently cooling the computer chip. Here, by making full use of the double merits of the liquid metal, i.e. superior heat transfer performance and electromagnetically drivable ability, we demonstrate for the first time the liquid-cooling concept for the thermal management of a computer chip using waste heat to power the thermoelectric generator (TEG) and thus the flow of the liquid metal. Such a device consumes no external net energy, which warrants it a self-supporting and completely silent liquid-cooling module. Experiments on devices driven by one or two stage TEGs indicate that a dramatic temperature drop on the simulating chip has been realized without the aid of any fans. The higher the heat load, the larger will be the temperature decrease caused by the cooling device. Further, the two TEGs will generate a larger current if a copper plate is sandwiched between them to enhance heat dissipation there. This new method is expected to be significant in future thermal management of a desk or notebook computer, where both efficient cooling and extremely low energy consumption are of major concern.

  14. Implementation of a Peltier-based cooling device for localized deep cortical deactivation during in vivo object recognition testing

    NASA Astrophysics Data System (ADS)

    Marra, Kyle; Graham, Brett; Carouso, Samantha; Cox, David

    2012-02-01

    While the application of local cortical cooling has recently become a focus of neurological research, extended localized deactivation deep within brain structures is still unexplored. Using a wirelessly controlled thermoelectric (Peltier) device and water-based heat sink, we have achieved inactivating temperatures (<20 C) at greater depths (>8 mm) than previously reported. After implanting the device into Long Evans rats' basolateral amygdala (BLA), an inhibitory brain center that controls anxiety and fear, we ran an open field test during which anxiety-driven behavioral tendencies were observed to decrease during cooling, thus confirming the device's effect on behavior. Our device will next be implanted in the rats' temporal association cortex (TeA) and recordings from our signal-tracing multichannel microelectrodes will measure and compare activated and deactivated neuronal activity so as to isolate and study the TeA signals responsible for object recognition. Having already achieved a top performing computational face-recognition system, the lab will utilize this TeA activity data to generalize its computational efforts of face recognition to achieve general object recognition.

  15. Study of active cooling for supersonic transports

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.; Morris, R. E.

    1975-01-01

    The potential benefits of using the fuel heat sink of hydrogen fueled supersonic transports for cooling large portions of the aircraft wing and fuselage are examined. The heat transfer would be accomplished by using an intermediate fluid such as an ethylene glycol-water solution. Some of the advantages of the system are: (1) reduced costs by using aluminum in place of titanium, (2) reduced cabin heat loads, and (3) more favorable environmental conditions for the aircraft systems. A liquid hydrogen fueled, Mach 2.7 supersonic transport aircraft design was used for the reference uncooled vehicle. The cooled aircraft designs were analyzed to determine their heat sink capability, the extent and location of feasible cooled surfaces, and the coolant passage size and spacing.

  16. Active cooling from the sixties to NASP

    NASA Technical Reports Server (NTRS)

    Kelly, H. Neale; Blosser, Max L.

    1994-01-01

    Vehicles, such as the X-15 or the National Aerospace Plane (NASP), traveling at hypersonic speeds through the earth's atmosphere experience aerodynamic heating. The heating can be severe enough that a thermal protection system is required to limit the temperature of the vehicle structure. Although several categories of thermal protection systems are mentioned briefly, the majority of the present paper describes convectively cooled structures for large areas. Convective cooling is a method of limiting structural temperatures by circulating a coolant through the vehicle structure. Efforts to develop convectively cooled structures during the past 30 years, from early engine structures which were intended to be tested on the X-15 to structural panels fabricated and tested under the NASP program, are described. Many of the lessons learned from these research efforts are presented.

  17. Active cooling from the sixties to NASP

    NASA Technical Reports Server (NTRS)

    Kelly, H. Neale; Blosser, Max L.

    1992-01-01

    Vehicles, such as the X-15 or National Aero-Space Plane, traveling at hypersonic speeds through the earth's atmosphere experience aerodynamic heating. The heating can be severe enough that a thermal protection system is required to limit the temperature of the vehicle structure. Although several categories of thermal protection systems are mentioned briefly, the majority of this paper describes convectively cooled structures for large areas. Convective cooling is a method of limiting structural temperatures by circulating a coolant through the vehicle structure. Efforts to develop convectively cooled structures during the past 30 years--from early engine structures, which were intended to be tested on the X-15, to structural--are described. Many of the lessons learned from these research efforts are presented.

  18. Electron guns and collectors developed at INP for electron cooling devices

    SciTech Connect

    Sharapa, A.N.; Shemyakin, A.V.

    1997-09-01

    Institute of Nuclear Physics (INP) has a rich experience in designing electron guns and collectors for electron cooling devices. This paper is a review of the experience of several INP research groups in this field. Some results obtained at INP for systems without a guiding magnetic field are also discussed.

  19. Simulation of an active cooling system for photovoltaic modules

    NASA Astrophysics Data System (ADS)

    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.

  20. Modeling a Transient Pressurization with Active Cooling Sizing Tool

    NASA Technical Reports Server (NTRS)

    Guzik, Monica C.; Plachta, David W.; Elchert, Justin P.

    2011-01-01

    As interest in the area of in-space zero boil-off cryogenic propellant storage develops, the need to visualize and quantify cryogen behavior during ventless tank self-pressurization and subsequent cool-down with active thermal control has become apparent. During the course of a mission, such as the launch ascent phase, there are periods that power to the active cooling system will be unavailable. In addition, because it is not feasible to install vacuum jackets on large propellant tanks, as is typically done for in-space cryogenic applications for science payloads, instances like the launch ascent heating phase are important to study. Numerous efforts have been made to characterize cryogenic tank pressurization during ventless cryogen storage without active cooling, but few tools exist to model this behavior in a user-friendly environment for general use, and none exist that quantify the marginal active cooling system size needed for power down periods to manage tank pressure response once active cooling is resumed. This paper describes the Transient pressurization with Active Cooling Tool (TACT), which is based on a ventless three-lump homogeneous thermodynamic self-pressurization model1 coupled with an active cooling system estimator. TACT has been designed to estimate the pressurization of a heated but unvented cryogenic tank, assuming an unavailable power period followed by a given cryocooler heat removal rate. By receiving input data on the tank material and geometry, propellant initial conditions, and passive and transient heating rates, a pressurization and recovery profile can be found, which establishes the time needed to return to a designated pressure. This provides the ability to understand the effect that launch ascent and unpowered mission segments have on the size of an active cooling system. A sample of the trends found show that an active cooling system sized for twice the steady state heating rate would results in a reasonable time for tank

  1. Thermoelastic stress analysis of multilayered films in a micro-thermoelectric cooling device

    NASA Astrophysics Data System (ADS)

    Yang, Yu-Mei; Wang, Xing-Zhe; Zhang, Wen-Jie

    2012-12-01

    This paper presents an analytical solution for the thermoelastic stress in a typical in-plane's thin-film micro-thermoelectric cooling device under different operating conditions. The distributions of the permissible temperature fields in multilayered thin-films are analytically obtained, and the characteristics, including maximum temperature difference and maximum refrigerating output of the thermoelectric device, are discussed for two operating conditions. Analytical expressions of the thermoelastic stresses in the layered thermoelectric thin-films induced by the temperature difference are formulated based on the theory of multilayer system. The results demonstrate that, the geometric dimension is a significant factor which remarkably affects the thermoelastic stresses. The stress distributions in layers of semiconductor thermoelements, insulating and supporting membrane show distinctly different features. The present work may profitably guide the optimization design of high-efficiency micro-thermoelectric cooling devices.

  2. Method and apparatus for actively controlling a micro-scale flexural plate wave device

    DOEpatents

    Dohner, Jeffrey L.

    2001-01-01

    An actively controlled flexural plate wave device provides a micro-scale pump. A method of actively controlling a flexural plate wave device produces traveling waves in the device by coordinating the interaction of a magnetic field with actively controlled currents. An actively-controlled flexural plate wave device can be placed in a fluid channel and adapted for use as a micro-scale fluid pump to cool or drive micro-scale systems, for example, micro-chips, micro-electrical-mechanical devices, micro-fluid circuits, or micro-scale chemical analysis devices.

  3. Evaluation of a carbon dioxide personal cooling device for workers in hot environments.

    PubMed

    Zhang, Yang; Bishop, Phillip A; Green, James Matthew; Richardson, Mark T; Schumacker, Randall E

    2010-07-01

    This study tested the effectiveness of a carbon dioxide cooling device in reducing heat strain for workers in a hot and humid environment. Ten participants completed two trials in an environment of 30 degrees C WBGT (75% relative humidity) with a novel liquid carbon dioxide cooling shirt (CC) or no cooling (NC) in a randomized order. Mean time-weighted workload for each individual equaled 465 W (400 Kcals. h(-1)). In the CC condition, the work time was significantly increased by 32% (97 +/- 36 min) compared with NC (74 +/- 26 min) (p < 0.05). There was no significant difference in mean skin temperature over the trials. Rectal temperature (T(re)) was significantly different after 50 min (p < 0.05). Mean heart rate, the delta T(re) increase rate, and heat storage at 55 min (last point with n = 8) were significantly lower in CC (p < 0.05). Overall heat storage was 54 +/- 41 W and 72 +/- 40 W for CC and NC, respectively (p < 0.05). Participants also indicated favorable subjective responses for CC vs. NC (p < 0.05). These findings suggest that this novel cooling device would effectively attenuate heat strain and increase work productivity for personnel working in a hot and humid environment. Practical aspects of use such as cost, convenience, weight, cooling duration, and rise in ambient CO(2) concentration in confined spaces must also be considered.

  4. Physiological and subjective responses to cooling devices on firefighting protective clothing.

    PubMed

    Chou, Chinmei; Tochihara, Yutaka; Kim, Taegyou

    2008-09-01

    The aim of the present study was to examine the effectiveness of ice-packs (ICE) and phase change material (PCM) cooling devices in reducing physiological load based on subjects' physiological and subjective responses while the subjects exercised on a bicycle ergometer while wearing firefighting protective clothing in a relatively high temperature environment (30 degrees C, 50%RH). Subjects were eight graduate students, aged 25.9 years (SD 3.2). Each subject participated in four 50-min exposures: control (CON), ICE, PCM of 5 degrees C [PCM(5)] and 20 degrees C [PCM(20)]. Each subject rested in a pre-test room for 10 min before entering the test-room where they rested for another 10 min, followed by 30 min-exercise and a 10 min-recovery period. The exercise intensity was set at 55%VO(2max). Cooling effects were evaluated by measuring rectal temperature (Tre), mean skin temperature (Tsk), body weight loss and subjective responses. An increase in Tre for PCM(5) and PCM(20) which was less than that for CON and ICE was observed. The increases in Tsk were depressed using cooling devices, but the cooling effects of PCMs were greater than ICE. The subjects with CON felt hotter and wetter than those in the other conditions. The larger surface cooling area, higher melting temperature and softer material of PCMs which reduces absorption capacity caused a decrease in Tre and Tsk for PCM(5) and PCM(20) which was more than that for CON and ICE. Furthermore, PCM(20) does not require refrigeration. These results suggest that PCM(20) is more effective than other cooling devices in reducing the physiological load while wearing firefighting protective clothing.

  5. Low material budget microfabricated cooling devices for particle detectors and front-end electronics

    NASA Astrophysics Data System (ADS)

    Mapelli, A.; Catinaccio, A.; Daguin, J.; van Lintel, H.; Nuessle, G.; Petagna, P.; Renaud, P.

    2011-06-01

    Novel cooling systems with very low material budget are being fabricated and studied. They consist of silicon wafers in which microchannels are etched and closed by bonding another wafer. This cooling option is being considered for future HEP detectors of the sLHC and linear colliders. It is currently under investigation as an option for the cooling of the NA62 Gigatracker silicon pixel detector and its front-end electronics where the microfabricated cooling plate would stand directly in the beam. In this particular case, microchannel cooling meets both the very aggressive X 0 (0.15%) specifications and the anticipated 2 W/cm 2 power dissipation by the active electronics.

  6. Rapid PCR amplification using a microfluidic device with integrated microwave heating and air impingement cooling.

    PubMed

    Shaw, Kirsty J; Docker, Peter T; Yelland, John V; Dyer, Charlotte E; Greenman, John; Greenway, Gillian M; Haswell, Stephen J

    2010-07-07

    A microwave heating system is described for performing polymerase chain reaction (PCR) in a microfluidic device. The heating system, in combination with air impingement cooling, provided rapid thermal cycling with heating and cooling rates of up to 65 degrees C s(-1) and minimal over- or under-shoot (+/-0.1 degrees C) when reaching target temperatures. In addition, once the required temperature was reached it could be maintained with an accuracy of +/-0.1 degrees C. To demonstrate the functionality of the system, PCR was successfully performed for the amplification of the Amelogenin locus using heating rates and quantities an order of magnitude faster and smaller than current commercial instruments.

  7. Self-Transport of Condensed Liquid in Micro Cooling Device Using Distributed Meniscus Pumping.

    PubMed

    So, Hongyun; Pisano, Albert P

    2015-06-16

    This paper reports a reliable passive micro pump system combining the physical properties of a tapered microchannel and sharp microstructures. This tailored microchannel with triple-spike microstructures was created to transport condensed liquid into the reservoir chamber in a micro cooling device and in the case of chip off-mode prepare the next cooling cycle before chip on-mode, allowing the reliable and continuous circulation of coolant without liquid being trapped in the vapor channel causing dryout limitation. At the tapered channel end, the pinned liquid meniscus was distributed by a middle spike and then continued to overflow into the condenser chamber due to extended capillary action.

  8. Preliminary design activities for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    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.

  9. Analysis of flavor and perfume using an internally cooled coated fiber device.

    PubMed

    Chen, Yong; Begnaud, Frédéric; Chaintreau, Alain; Pawliszyn, Janusz

    2007-05-01

    A miniaturized internally cooled coated fiber device was applied for the analysis of flavors and fragrances from various matrices. Its integration with a CTC CombiPAL autosampler enabled high throughput for the analysis of analytes in complex matrices that required simultaneous heating of the matrices and cooling of the fiber coating to achieve high extraction efficiency. It was found that up to ten times increase of extraction efficiencies was observed when the device was used to extract flavor compounds in water, even when limited sample temperatures were used to preserve the integrity of target compounds. The extraction of the flavor compounds in water with the device was reproducible, with RSD not larger than 15%. The lower limits of the linear ranges were in the low ppb range, which was about one order of magnitude smaller than those obtained with the commercialized 100 microm PDMS fibers. Exhaustive extraction of some perfume ingredients from a complex matrix (shampoo) was realized. All achieved recoveries were not less than 80%. The repeatability of the extraction of the perfume compounds from shampoo was better than 10%. The linear ranges were about 1-3000 microg/g, and the LOD was about 0.2-1 microg/g. The automated internally cooled coated fiber device was demonstrated to be a powerful sample preparation tool in flavor and fragrance analysis.

  10. A simple and highly stable free-flow electrophoresis device with thermoelectric cooling system.

    PubMed

    Yan, Jian; Guo, Cheng-Gang; Liu, Xiao-Ping; Kong, Fan-Zhi; Shen, Qiao-Yi; Yang, Cheng-Zhang; Li, Jun; Cao, Cheng-Xi; Jin, Xin-Qiao

    2013-12-20

    Complex assembly, inconvenient operations, poor control of Joule heating and leakage of solution are still fundamental issues greatly hindering application of free-flow electrophoresis (FFE) for preparative purpose in bio-separation. To address these issues, a novel FFE device was developed based on our previous work. Firstly, a new mechanical structure was designed for compact assembly of separation chamber, fast removal of air bubble, and good anti-leakage performance. Secondly, a highly efficient thermoelectric cooling system was used for dispersing Joule heating for the first time. The systemic experiments revealed the three merits: (i) 3min assembly without any liquid leakage, 80 times faster than pervious FFE device designed by us or commercial device (4h); (ii) 5s removing of air bubble in chamber, 1000-fold faster than a normal one (2h or more) and (iii) good control of Joule heating by the cooling system. These merits endowed the device high stable thermo- and hydro-dynamic flow for long-term separation even under high electric field of 63V/cm. Finally, the developed device was used for up to 8h continuous separation of 5mg/mL fuchsin acid and purification of three model proteins of phycocyanin, myoglobin and cytochrome C, demonstrating the applicability of FFE. The developed FFE device has evident significance to the studies on stem cell, cell or organelle proteomics, and protein complex as well as micro- or nano-particles.

  11. Nanowire-integrated microporous silicon membrane for continuous fluid transport in micro cooling device

    NASA Astrophysics Data System (ADS)

    So, Hongyun; Cheng, Jim C.; Pisano, Albert P.

    2013-10-01

    We report an efficient passive micro pump system combining the physical properties of nanowires and micropores. This nanowire-integrated microporous silicon membrane was created to feed coolant continuously onto the surface of the wick in a micro cooling device to ensure it remains hydrated and in case of dryout, allow for regeneration of the system. The membrane was fabricated by photoelectrochemical etching to form micropores followed by hydrothermal growth of nanowires. This study shows a promising approach to address thermal management challenges for next generation electronic devices with absence of external power.

  12. Nanowire-integrated microporous silicon membrane for continuous fluid transport in micro cooling device

    SciTech Connect

    So, Hongyun; Pisano, Albert P.; Cheng, Jim C.

    2013-10-14

    We report an efficient passive micro pump system combining the physical properties of nanowires and micropores. This nanowire-integrated microporous silicon membrane was created to feed coolant continuously onto the surface of the wick in a micro cooling device to ensure it remains hydrated and in case of dryout, allow for regeneration of the system. The membrane was fabricated by photoelectrochemical etching to form micropores followed by hydrothermal growth of nanowires. This study shows a promising approach to address thermal management challenges for next generation electronic devices with absence of external power.

  13. Active cooling requirements for propellant storage

    NASA Technical Reports Server (NTRS)

    Klein, G. A.

    1984-01-01

    Recent NASA and DOD mission models have indicated future needs for orbital cryogenic storage and supply systems. Two thermal control systems which show the greatest promise for improving propellant storage life were evaluated. One system was an open cycle thermodynamic vent type with a refrigeration system for partial hydrogen reliquefaction located at the LH2 tank and a vapor cooled shield for integrated and non-integrated tank designs to reduce boiloff. The other was a closed system with direct refrigeration at the LH2 tank. A reversed Brayton cycle unit was baselined for the propellant processor. It is concluded that: (1) reliquefaction systems are not attractive for minimizing propellant boiloff; (2) open cycle systems may not be economically attractive for long term storage; (3) a number of refrigeration systems are available to assist in the long term storage of cryogenic propellants; and (4) shields can significantly improve the performance of mechanical coolers.

  14. An On-Site Thermoelectric Cooling Device for Cryotherapy and Control of Skin Blood Flow

    PubMed Central

    Mejia, Natalia; Dedow, Karl; Nguy, Lindsey; Sullivan, Patrick; Khoshnevis, Sepideh; Diller, Kenneth R.

    2015-01-01

    Cryotherapy involves the surface application of low temperatures to enhance the healing of soft tissue injuries. Typical devices embody a remote source of chilled water that is pumped through a circulation bladder placed on the treatment site. In contrast, the present device uses thermoelectric refrigeration modules to bring the cooling source directly to the tissue to be treated, thereby achieving significant improvements in control of therapeutic temperature while having a reduced size and weight. A prototype system was applied to test an oscillating cooling and heating protocol for efficacy in regulating skin blood perfusion in the treatment area. Data on 12 human subjects indicate that thermoelectric coolers (TECs) delivered significant and sustainable changes in perfusion for both heating (increase by (±SE) 173.0 ± 66.0%, P < 0.005) and cooling (decrease by (±SE) 57.7 ± 4.2%, P < 0.0005), thus supporting the feasibility of a TEC-based device for cryotherapy with local temperature regulation. PMID:26421089

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

    SciTech Connect

    Li, Yuan; Bryan, Greg L.

    2014-07-01

    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 ∼10{sup 11} M {sub ☉}. 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 {sub ☉} yr{sup –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.

  16. Micro free-flow IEF enhanced by active cooling and functionalized gels.

    PubMed

    Albrecht, Jacob W; Jensen, Klavs F

    2006-12-01

    Rapid free-flow IEF is achieved in a microfluidic device by separating the electrodes from the focusing region with porous buffer regions. Moving the electrodes outside enables the use of large electric fields without the detrimental effects of bubble formation in the active region. The anode and cathode porous buffer regions, which are formed by acrylamide functionalized with immobilized pH groups, allow ion transport while providing buffering capacity. Thermoelectric cooling mitigates the effects of Joule heating on sample focusing at high field strengths (approximately 500 V/cm). This localized cooling was observed to increase device performance. Rapid focusing of low-molecular-weight p/ markers and Protein G-mouse IgG complexes demonstrate the versatility of the technique. Simulations provide insight into and predict device performance based on a well-defined sample composition.

  17. Probing a Device's Active Atoms.

    PubMed

    Studniarek, Michał; Halisdemir, Ufuk; Schleicher, Filip; Taudul, Beata; Urbain, Etienne; Boukari, Samy; Hervé, Marie; Lambert, Charles-Henri; Hamadeh, Abbass; Petit-Watelot, Sebastien; Zill, Olivia; Lacour, Daniel; Joly, Loïc; Scheurer, Fabrice; Schmerber, Guy; Da Costa, Victor; Dixit, Anant; Guitard, Pierre André; Acosta, Manuel; Leduc, Florian; Choueikani, Fadi; Otero, Edwige; Wulfhekel, Wulf; Montaigne, François; Monteblanco, Elmer Nahuel; Arabski, Jacek; Ohresser, Philippe; Beaurepaire, Eric; Weber, Wolfgang; Alouani, Mébarek; Hehn, Michel; Bowen, Martin

    2017-03-13

    Materials science and device studies have, when implemented jointly as "operando" studies, better revealed the causal link between the properties of the device's materials and its operation, with applications ranging from gas sensing to information and energy technologies. Here, as a further step that maximizes this causal link, the paper focuses on the electronic properties of those atoms that drive a device's operation by using it to read out the materials property. It is demonstrated how this method can reveal insight into the operation of a macroscale, industrial-grade microelectronic device on the atomic level. A magnetic tunnel junction's (MTJ's) current, which involves charge transport across different atomic species and interfaces, is measured while these atoms absorb soft X-rays with synchrotron-grade brilliance. X-ray absorption is found to affect magnetotransport when the photon energy and linear polarization are tuned to excite FeO bonds parallel to the MTJ's interfaces. This explicit link between the device's spintronic performance and these FeO bonds, although predicted, challenges conventional wisdom on their detrimental spintronic impact. The technique opens interdisciplinary possibilities to directly probe the role of different atomic species on device operation, and shall considerably simplify the materials science iterations within device research.

  18. Shuttle active thermal control system development testing. Volume 5: Integrated radiator/expendable cooling system tests

    NASA Technical Reports Server (NTRS)

    Scheps, P. B.

    1974-01-01

    Tests were conducted to gather data on a space shuttle active control system (ATCS) incorporating both radiators and an expendable cooling device to provide vehicle heat removal. Two systems were tested and design information was provided for both nominal and limit conditions. The tests verified the concept that an integrated radiator/expendable cooling system can adequately maintain desired water quantities while responding to variations in heat loads and environments. In addition, the need for duct heating was demonstrated, while exhaust nozzle heating was also shown to be unnecessary.

  19. Cold fiber solid-phase microextraction device based on thermoelectric cooling of metal fiber.

    PubMed

    Haddadi, Shokouh Hosseinzadeh; Pawliszyn, Janusz

    2009-04-03

    A new cold fiber solid-phase microextraction device was designed and constructed based on thermoelectric cooling. A three-stage thermoelectric cooler (TEC) was used for cooling a copper rod coated with a poly(dimethylsiloxane) (PDMS) hollow fiber, which served as the solid-phase microextraction (SPME) fiber. The copper rod was mounted on a commercial SPME plunger and exposed to the cold surface of the TEC, which was enclosed in a small aluminum box. A heat sink and a fan were used to dissipate the generated heat at the hot side of the TEC. By applying an appropriate dc voltage to the TEC, the upper part of the copper rod, which was in contact to the cold side of the TEC, was cooled and the hollow fiber reached a lower temperature through heat transfer. A thermocouple was embedded in the cold side of the TEC for indirect measurement of the fiber temperature. The device was applied in quantitative analysis of off-flavors in a rice sample. Hexanal, nonanal, and undecanal were chosen as three off-flavors in rice. They were identified according to their retention times and analyzed by GC-flame ionization detection instrument. Headspace extraction conditions (i.e., temperature and time) were optimized. Standard addition calibration graphs were obtained at the optimized conditions and the concentrations of the three analytes were calculated. The concentration of hexanal was also measured using a conventional solvent extraction method (697+/-143ng/g) which was comparable to that obtained from the cold fiber SPME method (644+/-8). Moreover, the cold fiber SPME resulted in better reproducibility and shorter analysis time. Cold fiber SPME with TEC device can also be used as a portable device for field sampling.

  20. ACUTE CARDIOVASCULAR EFFECTS OF FIREFIGHTING AND ACTIVE COOLING DURING REHABILITATION

    PubMed Central

    Burgess, Jefferey L.; Duncan, Michael D.; Hu, Chengcheng; Littau, Sally R.; Caseman, Delayne; Kurzius-Spencer, Margaret; Davis-Gorman, Grace; McDonagh, Paul F.

    2012-01-01

    Objectives To determine the cardiovascular and hemostatic effects of fire suppression and post-exposure active cooling. Methods Forty-four firefighters were evaluated prior to and after a 12 minute live-fire drill. Next, 50 firefighters undergoing the same drill were randomized to post-fire forearm immersion in 10°C water or standard rehabilitation. Results In the first study, heart rate and core body temperature increased and serum C-reactive protein decreased but there were no significant changes in fibrinogen, sE-selectin or sL-selectin. The second study demonstrated an increase in blood coagulability, leukocyte count, factors VIII and X, cortisol and glucose, and a decrease in plasminogen and sP-selectin. Active cooling reduced mean core temperature, heart rate and leukocyte count. Conclusions Live-fire exposure increased core temperature, heart rate, coagulability and leukocyte count; all except coagulability were reduced by active cooling. PMID:23090161

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

    NASA Technical Reports Server (NTRS)

    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

  2. Medical Devices; General and Plastic Surgery Devices; Classification of the Scalp Cooling System To Reduce the Likelihood of Chemotherapy-Induced Alopecia. Final order.

    PubMed

    2016-02-12

    The Food and Drug Administration (FDA) is classifying the scalp cooling system to reduce the likelihood of chemotherapy-induced alopecia into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the scalp cooling system to reduce the likelihood of chemotherapy-induced alopecia's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

  3. Physical Properties of Cooling Plasma in Quiescent Active Region Loops

    NASA Astrophysics Data System (ADS)

    Landi, E.; Miralles, M. P.; Curdt, W.; Hara, H.

    2009-04-01

    In the present work, we use SOHO/SUMER, SOHO/UVCS, SOHO/EIT, SOHO/LASCO, STEREO/EUVI, and Hinode/EIS coordinated observations of an active region (AR 10989) at the west limb taken on 2008 April 8 to study the cooling of coronal loops. The cooling plasma is identified using the intensities of SUMER spectral lines emitted at temperatures in the 4.15 <= log T <= 5.45 range. EIS and SUMER spectral observations are used to measure the physical properties of the loops. We found that before cooling took place these loops were filled with coronal hole-like plasma, with temperatures in the 5.6 <= log T <= 5.9 range. SUMER spectra also allowed us to determine the plasma temperature, density, emission measure, element abundances, and dynamic status during the cooling process. The ability of EUVI to observe the emitting region from a different direction allowed us to measure the volume of the emitting region and estimate its emission measure. Comparison with values measured from line intensities provided us with an estimate of the filling factor. UVCS observations of the coronal emission above the active region showed no streamer structure associated with AR 10989 at position angles between 242°and 253fdg EIT, LASCO, and EUVI-A narrowband images and UVCS spectral observations were used to discriminate between different scenarios and monitor the behavior of the active region in time. The present study provides the first detailed measurements of the physical properties of cooling loops, a very important benchmark for theoretical models of loop cooling and condensation.

  4. Investigation on the AC loss characteristics of MgB 2 wires by using a conduction cooling device

    NASA Astrophysics Data System (ADS)

    Jin, H. B.; Li, Z.; Ryu, K.

    2011-11-01

    In this study, we have experimentally investigated the AC loss characteristics of MgB2 wires with matrix of Fe and Cu by using a conduction cooling device. We fabricated the conduction cooling device to cool MgB2 wires down to 4 K. We also developed our unique test method, which is called AC pulse technique, to evaluate their AC loss characteristics within few hundred milliseconds. The test results show that the AC loss of the Fe/MgB2 wire is mainly generated in the ferromagnetic Fe matrix. Its AC loss is ten times larger than that of the Cu/MgB2 wire. In this paper, the evaluation technique of AC loss by using the conduction cooling device is described and the test results are discussed.

  5. Actively Cooled SLMS(TM) Technology for HEL Applications

    NASA Technical Reports Server (NTRS)

    Jacoby, Marc T.; Goodman, William A.; Reily, Jack C.; Kegley, Jeffrey R.; Haight, Harlan J.; Tucker, John; Wright, Ernest R.; Hogue, William D.

    2005-01-01

    Mr. Jacoby is the Chief Scientist for Schafer's Lightweight Optical Systems business area with twenty four years experience in laser and optical systems for space and military applications. He and colleague Dr. Goodman conceived and developed Silicon Lightweight Mirrors (SLMS(TM)) technologies for space applications from the extreme UV to FAR IR wavelengths. Schafer has demonstrated two different methods for actively cooling our Silicon Lightweight Mirrors (SLMS(TM)) technology. Direct internal cooling was accomplished by flowing liquid nitrogen through the continuous open cell core of the SLMS(TM) mirror. Indirect external cooling was accomplished by flowing liquid nitrogen through a CTE matched Cesic square-tube manifold that was bonded to the back of the mirror in the center. Testing was done in the small 4-foot thermal/vacuum chamber located at the NASA/MSFC X-Ray Calibration Facility. Seven thermal diodes were located over the front side of the 5 inch diameter mirror and one was placed on the outlet side of the Cesic manifold. Results indicate that the mirror reaches steady state at 82K in less than four minutes for both cooling methods. The maximum temperature difference of the eight diodes was less than 200 mK when the mirror was internally cooled and covered with MLI to insulate it from the large 300 K aluminum plate that was used to mount it.

  6. Elastocaloric effect of Ni-Ti wire for application in a cooling device

    NASA Astrophysics Data System (ADS)

    Tušek, J.; Engelbrecht, K.; Mikkelsen, L. P.; Pryds, N.

    2015-03-01

    We report on the elastocaloric effect of a superelastic Ni-Ti wire to be used in a cooling device. Initially, each evaluated wire was subjected to 400 loading/unloading training cycles in order to stabilize its superelastic behavior. The wires were trained at different temperatures, which lead to different stabilized superelastic behaviors. The stabilized (trained) wires were further tested isothermally (at low strain-rate) and adiabatically (at high strain-rate) at different temperatures (from 312 K to 342 K). We studied the impact of the training temperature and resulting superelastic behavior on the adiabatic temperature changes. The largest measured adiabatic temperature change during loading was 25 K with a corresponding 21 K change during unloading (at 322 K). A special focus was put on the irreversibilities in the adiabatic temperature changes between loading and unloading. It was shown that there are two sources of the temperature irreversibilities: the hysteresis (and related entropy generation) and the temporary residual strain immediately after unloading, respectively. The latter results in the temporary bending of the wire and reduced negative adiabatic temperature change. The paper also shows the impact of the applied strain on the adiabatic temperature changes as well as the distribution of the elastocaloric effect over the wire during loading in the case of two wires trained at different temperatures and the virgin wire, respectively. In the end, we propose guidelines about the required material properties for an efficient elastocaloric cooling device.

  7. Corrosion development between liquid gallium and four typical metal substrates used in chip cooling device

    NASA Astrophysics Data System (ADS)

    Deng, Yue-Guang; Liu, Jing

    2009-06-01

    The limitation of the currently available thermal management method has put an ever serious challenge for computer chip designers. A liquid metal with low melting point around room temperature was recently identified as a powerful coolant of driving heat away because of its superior thermo-physical properties and the unique ability to be driven efficiently by a completely silent electromagnetic pump. However, the adoption of gallium, one of the best candidates as metal coolant so far, may cause serious corrosion to the structure materials and subsequently affect the performance or even dangerous running of the cooling system. To address this emerging critical issue, here the compatibility of gallium with four typical metal substrates (6063 Aluminum-Alloy, T2 Copper-Alloy, Anodic Coloring 6063 Aluminum-Alloy and 1Cr18Ni9 Stainless Steel) was comprehensively investigated in order to better understand the corrosion mechanisms and help find out the most suitable structure material for making a liquid metal cooling device. To grasp in detail the dynamic corrosion behavior, an image acquisition and contrasting method was developed. Moreover, corrosion morphology analyses were performed by means of scanning electron microscope (SEM). The chemical compositions of the corroded layers were evaluated using energy dispersive spectrometry (EDS). According to the experiments, it was found that, the corrosion of the 6063 Aluminum-Alloy was rather evident and serious under the temperature range for chip cooling. The loose corrosion product will not only have no protection for the inner substrate, but also accelerate the corrosion process. Compared to the 6063 Aluminum-Alloy, T2 Copper-Alloy showed a slow and general corrosion, but part of the corrosion product can shed from the substrate, which will accelerate corrosion action and may block the flowing channel. Anodic Coloring 6063 Aluminum-Alloy and 1Cr18Ni9 Stainless Steel were found to have excellent corrosion resistance among

  8. Experimental and numerical study of open-air active cooling

    NASA Astrophysics Data System (ADS)

    Al-Fifi, Salman Amsari

    The topic of my thesis is Experimental and Numerical Study of Open Air Active Cooling. The present research is intended to investigate experimentally and Numerically the effectiveness of cooling large open areas like stadiums, shopping malls, national gardens, amusement parks, zoos, transportation facilities and government facilities or even in buildings outdoor gardens and patios. Our cooling systems are simple cooling fans with different diameters and a mist system. This type of cooling systems has been chosen among the others to guarantee less energy consumption, which will make it the most favorable and applicable for cooling such places mentioned above. In the experiments, the main focus is to study the temperature domain as a function of different fan diameters aerodynamically similar in different heights till we come up with an empirical relationship that can determine the temperature domain for different fan diameters and for different heights of these fans. The experimental part has two stages. The first stage is devoted to investigate the maximum range of airspeed and profile for three different fan diameters and for different heights without mist, while the second stage is devoted to investigate the maximum range of temperature and profile for the three different diameter fans and for different heights with mist. The computational study is devoted to built an experimentally verified mathematical model to be used in the design and optimization of water mist cooling systems, and to compare the mathematical results to the experimental results and to get an insight of how to apply such evaporative mist cooling for different places for different conditions. In this study, numerical solution is presented based on experimental conditions, such dry bulb temperature, wet bulb temperature, relative humidity, operating pressure and fan airspeed. In the computational study, all experimental conditions are kept the same for the three fans except the fan airspeed

  9. Actively cooled plate fin sandwich structural panels for hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Smith, L. M.; Beuyukian, C. S.

    1979-01-01

    An unshielded actively cooled structural panel was designed for application to a hypersonic aircraft. The design was an all aluminum stringer-stiffened platefin sandwich structure which used a 60/40 mixture of ethylene glycol/water as the coolant. Eight small test specimens of the basic platefin sandwich concept and three fatigue specimens from critical areas of the panel design was fabricated and tested (at room temperature). A test panel representative of all features of the panel design was fabricated and tested to determine the combined thermal/mechanical performance and structural integrity of the system. The overall findings are that; (1) the stringer-stiffened platefin sandwich actively cooling concept results in a low mass design that is an excellent contender for application to a hypersonic vehicle, and (2) the fabrication processes are state of the art but new or modified facilities are required to support full scale panel fabrication.

  10. One-heater flow-through polymerase chain reaction device by heat pipes cooling

    PubMed Central

    Chen, Jyh Jian; Liao, Ming Huei; Li, Kun Tze; Shen, Chia Ming

    2015-01-01

    the cooling module that has been designed for a PCR device. The unique architecture utilized in this flow-through PCR device is well applied to a low-cost PCR system. PMID:25713689

  11. One-heater flow-through polymerase chain reaction device by heat pipes cooling.

    PubMed

    Chen, Jyh Jian; Liao, Ming Huei; Li, Kun Tze; Shen, Chia Ming

    2015-01-01

    the cooling module that has been designed for a PCR device. The unique architecture utilized in this flow-through PCR device is well applied to a low-cost PCR system.

  12. Acceleration Sensing, Feedback Cooling, and Nonlinear Dynamics with Nanoscale Cavity-Optomechanical Devices

    NASA Astrophysics Data System (ADS)

    Krause, Alexander Grey

    Light has long been used for the precise measurement of moving bodies, but the burgeoning field of optomechanics is concerned with the interaction of light and matter in a regime where the typically weak radiation pressure force of light is able to push back on the moving object. This field began with the realization in the late 1960's that the momentum imparted by a recoiling photon on a mirror would place fundamental limits on the smallest measurable displacement of that mirror. This coupling between the frequency of light and the motion of a mechanical object does much more than simply add noise, however. It has been used to cool objects to their quantum ground state, demonstrate electromagnetically-induced-transparency, and modify the damping and spring constant of the resonator. Amazingly, these radiation pressure effects have now been demonstrated in systems ranging 18 orders of magnitude in mass (kg to fg). In this work we will focus on three diverse experiments in three different optomechanical devices which span the fields of inertial sensors, closed-loop feedback, and nonlinear dynamics. The mechanical elements presented cover 6 orders of magnitude in mass (ng to fg), but they all employ nano-scale photonic crystals to trap light and resonantly enhance the light-matter interaction. In the first experiment we take advantage of the sub-femtometer displacement resolution of our photonic crystals to demonstrate a sensitive chip-scale optical accelerometer with a kHz-frequency mechanical resonator. This sensor has a noise density of approximately 10 micro-g/rt-Hz over a useable bandwidth of approximately 20 kHz and we demonstrate at least 50 dB of linear dynamic sensor range. We also discuss methods to further improve performance of this device by a factor of 10. In the second experiment, we used a closed-loop measurement and feedback system to damp and cool a room-temperature MHz-frequency mechanical oscillator from a phonon occupation of 6.5 million down to

  13. Hybrid optical-thermal devices and materials for light manipulation and radiative cooling

    NASA Astrophysics Data System (ADS)

    Boriskina, Svetlana V.; Tong, Jonathan K.; Hsu, Wei-Chun; Weinstein, Lee; Huang, Xiaopeng; Loomis, James; Xu, Yanfei; Chen, Gang

    2015-09-01

    We report on optical design and applications of hybrid meso-scale devices and materials that combine optical and thermal management functionalities owing to their tailored resonant interaction with light in visible and infrared frequency bands. We outline a general approach to designing such materials, and discuss two specific applications in detail. One example is a hybrid optical-thermal antenna with sub-wavelength light focusing, which simultaneously enables intensity enhancement at the operating wavelength in the visible and reduction of the operating temperature. The enhancement is achieved via light recycling in the form of whispering-gallery modes trapped in an optical microcavity, while cooling functionality is realized via a combination of reduced optical absorption and radiative cooling. The other example is a fabric that is opaque in the visible range yet highly transparent in the infrared, which allows the human body to efficiently shed energy in the form of thermal emission. Such fabrics can find numerous applications for personal thermal management and for buildings energy efficiency improvement.

  14. Superconducting electromechanical rotating device having a liquid-cooled, potted, one layer stator winding

    DOEpatents

    Dombrovski, Viatcheslav V.; Driscoll, David I.; Shovkhet, Boris A.

    2001-01-01

    A superconducting electromechanical rotating (SER) device, such as a synchronous AC motor, includes a superconducting field winding and a one-layer stator winding that may be water-cooled. The stator winding is potted to a support such as the inner radial surface of a support structure and, accordingly, lacks hangers or other mechanical fasteners that otherwise would complicate stator assembly and require the provision of an unnecessarily large gap between adjacent stator coil sections. The one-layer winding topology, resulting in the number of coils being equal to half the number of slots or other mounting locations on the support structure, allows one to minimize or eliminate the gap between the inner radial ends of adjacent straight sections of the stator coilswhile maintaining the gap between the coil knuckles equal to at least the coil width, providing sufficient room for electrical and cooling element configurations and connections. The stator winding may be potted to the support structure or other support, for example, by a one-step VPI process relying on saturation of an absorbent material to fill large gaps in the stator winding or by a two-step process in which small gaps are first filled via a VPI or similar operation and larger gaps are then filled via an operation that utilizes the stator as a portion of an on-site mold.

  15. SU-C-213-07: Fabrication and Testing of a 3D-Printed Small Animal Rectal Cooling Device to Evaluate Local Hypothermia as a Radioprotector During Prostate SBRT

    SciTech Connect

    Hrycushko, B; Chopra, R; Futch, C; Bing, C; Wodzak, M; Stojadinovic, S; Jiang, S; Medin, P

    2015-06-15

    Purpose: The protective effects of induced or even accidental hypothermia on the human body are widespread with several medical uses currently under active research. In vitro experiments using human cell lines have shown hypothermia provides a radioprotective effect that becomes more pronounced at large, single-fraction doses common to SBRT treatments. Relevant to prostate SBRT, this work details the fabrication and testing of a 3D-printed cooling device to facilitate the investigation of the radioprotective effect of local hypothermia on the rat rectum. Methods: A 3cm long, two-channel rectal cooling device was designed in SOLIDWORKS CAD for 3D printing. The water intake nozzle is connected to a 1mm diameter brass pipe from which water flows and circulates back around to the exit nozzle. Both nozzles are connected by plastic tubing to a water chiller pump. Following leak-proof testing, fiber optic temperature probes were used to evaluate the temperature over time when placed adjacent to the cooling device within a rat rectum. MRI thermometry characterized the relative temperature distribution in concentric ROIs surrounding the probe. CBCT images from a small-animal irradiator were evaluated for imaging artifacts which could affect Monte Carlo dose calculations during treatment planning. Results: The rectal temperature adjacent to the cooling device decreased from body temperature (37°C) to 15°C in 10–20 minutes from device insertion. Rectal temperature was maintained at 15±3°C during active cooling. MRI thermometry tests revealed a steep temperature gradient with increasing distance from the cooling device, with the desired temperature range maintained within the surrounding few millimeters. Conclusion: A 3D printed rectal cooling device was fabricated for the purpose of inducing local hypothermia in rat rectums. Rectal cooling capabilities were characterized in-vivo to facilitate an investigation of the radioprotective effect of hypothermia for late rectal

  16. Neutronics activities for next generation devices

    SciTech Connect

    Gohar, Y.

    1985-01-01

    Neutronic activities for the next generation devices are the subject of this paper. The main activities include TFCX and FPD blanket/shield studies, neutronic aspects of ETR/INTOR critical issues, and neutronics computational modules for the tokamak system code and tandem mirror reactor system code. Trade-off analyses, optimization studies, design problem investigations and computational models development for reactor parametric studies carried out for these activities are summarized.

  17. Characterization of AN Actively Cooled Metal Foil Thermal Radiation Shield

    NASA Astrophysics Data System (ADS)

    Feller, J. R.; Kashani, A.; Helvensteijn, B. P. M.; Salerno, L. J.

    2010-04-01

    Zero boil-off (ZBO) or reduced boil-off (RBO) systems that involve active cooling of large cryogenic propellant tanks will most likely be required for future space exploration missions. For liquid oxygen or methane, such systems could be implemented using existing high technology readiness level (TRL) cryocoolers. However, for liquid hydrogen temperatures (˜20 K) no such coolers exist. In order to partially circumvent this technology gap, the concept of broad area cooling (BAC) has been developed, whereby a low mass thermal radiation shield could be maintained at temperatures around 100 K by steady circulation of cold pressurized gas through a network of narrow tubes. By this method it is possible to dramatically reduce the radiative heat leak to the 20 K tank. A series of experiments, designed to investigate the heat transfer capabilities of BAC systems, have been conducted at NASA Ames Research Center (ARC). Results of the final experiment in this series, investigating heat transfer from a metal foil film to a distributed cooling line, are presented here.

  18. CHARACTERIZATION OF AN ACTIVELY COOLED METAL FOIL THERMAL RADIATION SHIELD

    SciTech Connect

    Feller, J. R.; Salerno, L. J.; Kashani, A.; Helvensteijn, B. P. M.

    2010-04-09

    Zero boil-off (ZBO) or reduced boil-off (RBO) systems that involve active cooling of large cryogenic propellant tanks will most likely be required for future space exploration missions. For liquid oxygen or methane, such systems could be implemented using existing high technology readiness level (TRL) cryocoolers. However, for liquid hydrogen temperatures (approx20 K) no such coolers exist. In order to partially circumvent this technology gap, the concept of broad area cooling (BAC) has been developed, whereby a low mass thermal radiation shield could be maintained at temperatures around 100 K by steady circulation of cold pressurized gas through a network of narrow tubes. By this method it is possible to dramatically reduce the radiative heat leak to the 20 K tank. A series of experiments, designed to investigate the heat transfer capabilities of BAC systems, have been conducted at NASA Ames Research Center (ARC). Results of the final experiment in this series, investigating heat transfer from a metal foil film to a distributed cooling line, are presented here.

  19. [Batteries Used in Active Implantable Medical Devices].

    PubMed

    Ma, Bozhi; Hao, Hongwei; Li, Luming

    2015-03-01

    In recent years active implantable medical devices(AIMD) are being developed rapidly. Many battery systems have been developed for different AIMD applications. These batteries have the same requirements which include high safety, reliability, energy density and long service life, discharge indication. History, present and future of batteries used in AIMD are introduced in the article.

  20. Fluid-cooled heat sink with improved fin areas and efficiencies for use in cooling various devices

    SciTech Connect

    Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth; Narumanchi, Sreekant

    2015-04-21

    The disclosure provides a fluid-cooled heat sink having a heat transfer base and a plurality of heat transfer fins in thermal communication with the heat transfer base, where the heat transfer base and the heat transfer fins form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop of the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.

  1. (DARPA) Optical Radiation Cooling and Heating In Integrated Devices: Circuit cavity optomechanics for cooling and amplification on a silicon chip

    DTIC Science & Technology

    2015-07-16

    9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) DARPA ORCHID through AFOSR 10. SPONSOR/MONITOR’S ACRONYM(S) AFOSR 11. SPONSOR/MONITOR’S...REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT For public release 13. SUPPLEMENTARY NOTES 14. ABSTRACT In this DARPA’s ORCHID program, Yale...DISTRIBUTION A: Distribution approved for public release. 1 DARPA ORCHID Final Report “Circuit cavity optomechanics for cooling and amplification on a

  2. Design Of A Hybrid Jet Impingement / Microchannel Cooling Device For Densely Packed PV Cells Under High Concentration

    NASA Astrophysics Data System (ADS)

    Barrau, Jérôme; Rosell, Joan; Ibañez, Manel

    2010-10-01

    A hybrid jet impingement / microchannel cooling scheme was designed and applied to densely packed PV cells under high concentration. An experimental study allows validating the principles of the design and confirming its applicability to the cited system. In order to study the characteristics of the device in a wide range of conditions, a numerical model was developed and experimentally validated. The results allow evaluating the contributions of the cooling device to the performances of densely packed PV cells under high concentration. The main advantages of the system are related to its compactness, its good capacity of heat extraction associated to relatively low pressure losses and its capability to improve the temperature uniformity of the PV receiver with respect to other cooling schemes. These features improve the net electric output of the whole system and its reliability.

  3. A microfluidic device providing continuous-flow polymerase chain reaction heating and cooling

    NASA Astrophysics Data System (ADS)

    Harandi, A.; Farquhar, T.

    2014-11-01

    The objective of this study is to describe a new type of microfluidic device that could be used to manipulate fluid temperature in many microfluidic applications. The key component is a composite material containing a thermally conductive phase placed in a purposeful manner to manipulate heat flow into and out of an embedded microchannel. In actual use, the device is able to vary temperature along a defined flow path with remarkable precision. As a demonstration of capability, a functional prototype was designed and fabricated using four layers of patterned copper laminated between alternating layers of polyimide and acrylic. The key fabrication steps included laser micromachining, acid etching, microchannel formation, and hot lamination. In order to achieve the desired temperature variations along the microchannel, an outer optimization loop and an inner finite element analysis loop were used to iteratively obtain a near-optimal copper pattern. With a minor loss of generality, admissible forms were restricted to comb-like patterns. For a given temperature profile, the pattern was found by refining a starting guess based on a deterministic rubric. Thermal response was measured using fine thermocouples placed at critical locations along the microchannel wall. At most of these points, the agreement between measured and predicted temperatures was within 1 °C, and temperature gradients as high as ±45 °C mm-1 (equivalent to ±90 °C s-1 at 2 μl min-1 flow rate) were obtained within the range of 59-91 °C. The particular profile chosen for case study makes it possible to perform five cycles of continuous-flow polymerase chain reaction (PCR) in less than 15 s, i.e. it entails five successive cycles of cooling from 91 to 59 °C, rapid reheating from 59 to 73 °C, slow reheating from 73 to 76 °C, and a final reheating from 73 to 91 °C, using a resistively heated source at 100 °C at and a thermoelectrically cooled sink at 5 °C.

  4. Active superconducting devices formed of thin films

    DOEpatents

    Martens, Jon S.; Beyer, James B.; Nordman, James E.; Hohenwarter, Gert K. G.

    1991-05-28

    Active superconducting devices are formed of thin films of superconductor which include a main conduction channel which has an active weak link region. The weak link region is composed of an array of links of thin film superconductor spaced from one another by voids and selected in size and thickness such that magnetic flux can propagate across the weak link region when it is superconducting. Magnetic flux applied to the weak link region will propagate across the array of links causing localized loss of superconductivity in the links and changing the effective resistance across the links. The magnetic flux can be applied from a control line formed of a superconducting film deposited coplanar with the main conduction channel and weak link region on a substrate. The devices can be formed of any type to superconductor but are particularly well suited to the high temperature superconductors since the devices can be entirely formed from coplanar films with no overlying regions. The devices can be utilized for a variety of electrical components, including switching circuits, amplifiers, oscillators and modulators, and are well suited to microwave frequency applications.

  5. Numerical comparison of convective heat transfer augmentation devices used in cooling channels of hypersonic vehicles

    NASA Technical Reports Server (NTRS)

    Maldonado, Jaime J.

    1994-01-01

    Hypersonic vehicles are exposed to extreme thermal conditions compared to subsonic aircraft; therefore, some level of thermal management is required to protect the materials used. Normally, hypersonic vehicles experience the highest temperatures in the nozzle throat, and aircraft and propulsion system leading edges. Convective heat transfer augmentation techniques can be used in the thermal management system to increase heat transfer of the cooling channels in those areas. The techniques studied in this report are pin-fin, offset-fin, ribbed and straight roughened channel. A smooth straight channel is used as the baseline for comparing the techniques. SINDA '85, a lumped parameter finite difference thermal analyzer, is used to model the channels. Subroutines are added to model the fluid flow assuming steady one dimensional compressible flow with heat addition and friction. Correlations for convective heat transfer and friction are used in conjunction with the fluid flow analysis mentioned. As expected, the pin-fin arrangement has the highest heat transfer coefficient and the largest pressure drop. All the other devices fall in between the pin-fin and smooth straight channel. The selection of the best heat augmentation method depends on the design requirements. A good approach may be a channel using a combination of the techniques. For instance, several rows of pin-fins may be located at the region of highest heat flux, surrounded by some of the other techniques. Thus, the heat transfer coefficient is maximized at the region of highest heat flux while the pressure drop is not excessive.

  6. Indocyanine green videoangiography using cooled charge-coupled devices in central serous choroidopathy

    NASA Astrophysics Data System (ADS)

    Ciamberlini, C.; Guarnieri, V.; Longobardi, Giuseppe; Poggi, Pasquale; Donati, M. C.; Panzardi, G.; Panzardi, G.

    1997-04-01

    In order to evaluate the use of low level light (LLL) indocyanine green angiography in the diagnosis and treatment of central serous choroidopathy (CSC), a new system for LLL infrared videoangiography is described. The system was coupled with a standard fundus camera employing a low-power continuous light source. The system consists of a cooled charge-coupled device (CCD) camera and a third-generation image intensifier. The CCD camera investigates the pathologies of choroidal images with very good performance in terms of spatial resolution, dynamic range, and signal- to-noise ratio. The image intensifier carries out the choroidal angiography in real time. The results of 48 cases of CSC demonstrated the following ICGV features: focal RPE leakage; hyperfluorescent areas appearing in late phases and underlying the focal leakage or pigment epithelium detachment (PED); PED in the guise of early hyperfluorescence areas; delays in choroidal filling. The findings support the hypothesis that CSC originates in the choroid with localized hyperpermeability. The system described minimized retinal illumination and demonstrated increased angiographic resolution and contrast compared with conventional ICG angiographic systems.

  7. Fabrication of an inexpensive, implantable cooling device for reversible brain deactivation in animals ranging from rodents to primates

    PubMed Central

    Cooke, Dylan F.; Goldring, Adam B.; Yamayoshi, Itsukyo; Tsourkas, Phillippos; Recanzone, Gregg H.; Tiriac, Alex; Pan, Tingrui; Simon, Scott I.

    2012-01-01

    We have developed a compact and lightweight microfluidic cooling device to reversibly deactivate one or more areas of the neocortex to examine its functional macrocircuitry as well as behavioral and cortical plasticity. The device, which we term the “cooling chip,” consists of thin silicone tubing (through which chilled ethanol is circulated) embedded in mechanically compliant polydimethylsiloxane (PDMS). PDMS is tailored to compact device dimensions (as small as 21 mm3) that precisely accommodate the geometry of the targeted cortical area. The biocompatible design makes it suitable for both acute preparations and chronic implantation for long-term behavioral studies. The cooling chip accommodates an in-cortex microthermocouple measuring local cortical temperature. A microelectrode may be used to record simultaneous neural responses at the same location. Cortex temperature is controlled by computer regulation of the coolant flow, which can achieve a localized cortical temperature drop from 37 to 20°C in less than 3 min and maintain target temperature to within ±0.3°C indefinitely. Here we describe cooling chip fabrication and performance in mediating cessation of neural signaling in acute preparations of rodents, ferrets, and primates. PMID:22402651

  8. Electric Current Dependence of a Self-Cooling Device Consisting of Silicon Wafers Connected to a Power MOSFET

    NASA Astrophysics Data System (ADS)

    Nakatsugawa, H.; Okamoto, Y.; Kawahara, T.; Yamaguchi, S.

    2014-06-01

    A self-cooling device has been developed by combining a commercial n-channel power metal-oxide-semiconductor field-effect transistor (MOSFET) and single-crystalline Sb-doped n-type or B-doped p-type silicon wafers in order to improve the heat removal or cooling quantitatively. The electric current dependence of the temperature distribution in the self-cooling device and the voltage between the source and drain electrodes have been measured to estimate the Peltier heat flux. We found that the average temperature is decreased for a power MOSFET in which an electric current of 50 A flows. In particular, the average temperature of the power MOSFET was decreased by 2.7°C with the n-type Si wafer and by 3.5°C with the p-type Si wafer, although an electric current of 40 A makes little difference. This certainly warrants further work with improved measurement conditions. Nonetheless, the results strongly indicate that such n-type or p-type silicon wafers are candidate materials for use in self-cooling devices.

  9. Fabrication of an inexpensive, implantable cooling device for reversible brain deactivation in animals ranging from rodents to primates.

    PubMed

    Cooke, Dylan F; Goldring, Adam B; Yamayoshi, Itsukyo; Tsourkas, Phillippos; Recanzone, Gregg H; Tiriac, Alex; Pan, Tingrui; Simon, Scott I; Krubitzer, Leah

    2012-06-01

    We have developed a compact and lightweight microfluidic cooling device to reversibly deactivate one or more areas of the neocortex to examine its functional macrocircuitry as well as behavioral and cortical plasticity. The device, which we term the "cooling chip," consists of thin silicone tubing (through which chilled ethanol is circulated) embedded in mechanically compliant polydimethylsiloxane (PDMS). PDMS is tailored to compact device dimensions (as small as 21 mm(3)) that precisely accommodate the geometry of the targeted cortical area. The biocompatible design makes it suitable for both acute preparations and chronic implantation for long-term behavioral studies. The cooling chip accommodates an in-cortex microthermocouple measuring local cortical temperature. A microelectrode may be used to record simultaneous neural responses at the same location. Cortex temperature is controlled by computer regulation of the coolant flow, which can achieve a localized cortical temperature drop from 37 to 20°C in less than 3 min and maintain target temperature to within ±0.3°C indefinitely. Here we describe cooling chip fabrication and performance in mediating cessation of neural signaling in acute preparations of rodents, ferrets, and primates.

  10. Active Optical Devices and Applications. Volume 228

    DTIC Science & Technology

    1980-04-01

    obscuration, 5-cm-thick solid, segmented (6 petals) Zerodur . Mirror A is near the limit of what can be fabricated with current technology. The honeycomb...DEW Descriptors, Keywords: Active Optical Device Application Large Optics Adaptive Technology Wavefront Sensor Deformable Mirror Performance...Cuneo, Jr., U.S. Air Force, NASA Headquarters 228-01 Wavefront sensors and deformable mirrors for visible wavelengths 4 Noah Bareket, Lockheed

  11. Cooling apparatus and method

    DOEpatents

    Mayes, James C.

    2009-05-05

    A device and method provide for cooling of a system having an energy source, one or more devices that actively consume energy, and one or more devices that generate heat. The device may include one or more thermoelectric coolers ("TECs") in conductive engagement with at least one of the heat-generating devices, and an energy diverter for diverting at least a portion of the energy from the energy source that is not consumed by the active energy-consuming devices to the TECs.

  12. Fluid flow and heat convection studies for actively cooled airframes

    NASA Astrophysics Data System (ADS)

    Mills, A. F.

    This report details progress made on the jet impingement - liquid crystal - digital imaging experiment. With the design phase complete, the experiment is currently in the construction phase. In order to reach this phase two design related issues were resolved. The first issue was to determine NASP leading edge active cooling design parameters. Meetings were arranged with personnel at SAIC International, Torrance, CA in order to obtain recent publications that characterized expected leading edge heat fluxes as well as other details of NASP operating conditions. The information in these publications was used to estimate minimum and maximum jet Reynolds numbers needed to accomplish the required leading edge cooling, and to determine the parameters of the experiment. The details of this analysis are shown in Appendix A. One of the concerns for the NASP design is that of thermal stress due to large surface temperature gradients. Using a series of circular jets to cool the leading edge will cause a non-uniform temperature distribution and potentially large thermal stresses. Therefore it was decided to explore the feasibility of using a slot jet to cool the leading edge. The literature contains many investigations into circular jet heat transfer but few investigations of slot jet heat transfer. The first experiments will be done on circular jets impinging on a fiat plate and results compared to previously published data to establish the accuracy of the method. Subsequent experiments will be slot jets impinging on full scale models of the NASP leading edge. Table 1 shows the range of parameters to be explored. Next a preliminary design of the experiment was done. Previous papers which used a similar experimental technique were studied and elements of those experiments adapted to the jet impingement study. Trade-off studies were conducted to determine which design was the least expensive, easy to construct, and easy to use. Once the final design was settled, vendors were

  13. Fluid flow and heat convection studies for actively cooled airframes

    NASA Technical Reports Server (NTRS)

    Mills, A. F.

    1993-01-01

    This report details progress made on the jet impingement - liquid crystal - digital imaging experiment. With the design phase complete, the experiment is currently in the construction phase. In order to reach this phase two design related issues were resolved. The first issue was to determine NASP leading edge active cooling design parameters. Meetings were arranged with personnel at SAIC International, Torrance, CA in order to obtain recent publications that characterized expected leading edge heat fluxes as well as other details of NASP operating conditions. The information in these publications was used to estimate minimum and maximum jet Reynolds numbers needed to accomplish the required leading edge cooling, and to determine the parameters of the experiment. The details of this analysis are shown in Appendix A. One of the concerns for the NASP design is that of thermal stress due to large surface temperature gradients. Using a series of circular jets to cool the leading edge will cause a non-uniform temperature distribution and potentially large thermal stresses. Therefore it was decided to explore the feasibility of using a slot jet to cool the leading edge. The literature contains many investigations into circular jet heat transfer but few investigations of slot jet heat transfer. The first experiments will be done on circular jets impinging on a fiat plate and results compared to previously published data to establish the accuracy of the method. Subsequent experiments will be slot jets impinging on full scale models of the NASP leading edge. Table 1 shows the range of parameters to be explored. Next a preliminary design of the experiment was done. Previous papers which used a similar experimental technique were studied and elements of those experiments adapted to the jet impingement study. Trade-off studies were conducted to determine which design was the least expensive, easy to construct, and easy to use. Once the final design was settled, vendors were

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

    SciTech Connect

    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.

  15. Active solar heating and cooling information user study

    SciTech Connect

    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.

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

    SciTech Connect

    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)

  17. Micro-Stirling Active Cooling Module (MS/ACM) for DoD Electronics Systems

    DTIC Science & Technology

    2012-03-01

    Micro- Stirling Active Cooling Module (MS/ACM) for DoD Electronics Systems Douglas S. Beck Beck Engineering , Inc. 1490 Lumsden Road, Port Orchard...refrigerator. We are developing for DARPA a cm-scale Micro- Stirling Active Cooling Module (MS/ACM) micro- refrigerator to benefit the DoD systems. Under...a DARPA contract, we are designing, building, and demonstrating a breadboard MS/ACM. Keywords: Stirling ; cooler; active cooling module; micro

  18. Enhancement of Natural Convection by Carbon Nanotube Films Covered Microchannel-Surface for Passive Electronic Cooling Devices.

    PubMed

    Zhang, Guang; Jiang, Shaohui; Yao, Wei; Liu, Changhong

    2016-11-16

    Owing to the outstanding properties of thermal conduction, lightweight, and chemical durability, carbon nanotubes (CNTs) have revealed promising applications in thermal management materials. Meanwhile, the increasingly popular portable electronics and the rapid development of space technology need lighter weight, smaller size, and more effective thermal management devices. Here, a novel kind of heat dissipation devices based on the superaligned CNT films and underlying microchannels is proposed, and the heat dissipation properties are measured at the natural condition. Distinctive from previous studies, by combining the advantages of microchannels and CNTs, such a novel heat dissipation device enables superior natural convection heat transfer properties. Our findings prove that the novel CNT-based devices could show an 86.6% larger total natural heat dissipation properties than bare copper plate. Further calculations of the radiation and natural convection heat transfer properties demonstrate that the excellent passive cooling properties of these CNT-based devices are primarily caused by the reinforcement of the natural convection heat transfer properties. Furthermore, the heat dissipation mechanisms are briefly discussed, and we propose that the very high heat transfer coefficients and the porous structures of superaligned CNT films play critical roles in reinforcing the natural convection. The novel CNT-based heat dissipation devices also have advantages of energy-saving, free-noise, and without additional accessories. So we believe that the CNT-based heat dissipation devices would replace the traditional metal-finned heat dissipation devices and have promising applications in electronic devices, such as photovoltaic devices, portable electronic devices, and electronic displays.

  19. Design and evaluation of active cooling systems for Mach 6 cruise vehicle wings

    NASA Technical Reports Server (NTRS)

    Mcconarty, W. A.; Anthony, F. M.

    1971-01-01

    Active cooling systems, which included transpiration, film, and convective cooling concepts, are examined. Coolants included hydrogen, helium, air, and water. Heat shields, radiation barriers, and thermal insulation are considered to reduce heat flow to the cooling systems. Wing sweep angles are varied from 0 deg to 75 deg and wing leading edge radii of 0.05 inch and 2.0 inches are examined. Structural temperatures are varied to allow comparison of aluminum alloy, titanium alloy, and superalloy structural materials. Cooled wing concepts are compared among themselves, and with the uncooled concept on the basis of structural weight, cooling system weight, and coolant weight.

  20. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  1. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  2. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  3. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  4. 21 CFR 890.5050 - Daily activity assist device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Daily activity assist device. 890.5050 Section 890.5050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5050 Daily...

  5. Wissler Simulations of a Liquid Cooled and Ventilation Garment (LCVG) for Extravehicular Activity (EVA)

    NASA Technical Reports Server (NTRS)

    Kesterson, Matthew; Bue, Grant; Trevino, Luis

    2006-01-01

    In order to provide effective cooling for astronauts during extravehicular activities (EVAs), a liquid cooling and ventilation garment (LCVG) is used to remove heat by a series off tubes through which cooling water is circulated. To better predict the effectiveness of the LCG and determine possible modifications to improve performance, computer simulations dealing with the interaction of the cooling garment with the human body have been run using the Wissler Human Model. Simulations have been conducted to predict the heat removal rate for various liquid cooled garment configurations. The current LCVG uses 48 cooling tubes woven into a fabric with cooling water flowing through the tubes. The purpose of the current project is to decrease the overall weight of the LCVG system. In order to achieve this weight reduction, advances in the garment heat removal rates need to be obtained. Currently, increasing the fabric s thermal conductivity along with also examining an increase in the cooling tube conductivity to more efficiently remove the excess heat generated during EVA is being simulated. Initial trials varied cooling water temperature, water flow rate, garment conductivity, tube conductivity, and total number of cooling tubes in the LCVG. Results indicate that the total number of cooling tubes could be reduced to 22 and still achieve the desired heat removal rate of 361 W. Further improvements are being made to the garment network used in the model to account for temperature gradients associated with the spacing of the cooling tubes over the surface of the garment

  6. Graphene active plasmonics for terahertz device applications

    NASA Astrophysics Data System (ADS)

    Otsuji, Taiichi; Dubinov, Alexander; Ryzhii, Maxim; Boubanga Tombet, Stephane; Satou, Akira; Mitin, Vladimir; Shur, Michael S.; Ryzhii, Victor

    2015-05-01

    This paper reviews recent advances in the double-graphene-layer (DGL) active plasmonic heterostructures for the terahertz (THz) device applications. The DGL consists of a core shell in which a thin tunnel barrier layer is sandwiched by the two GLs being independently connected with the side contacts and outer gate stack layers at both sides. The DGL core shell works as a nano-capacitor, exhibiting inter-GL resonant tunneling (RT) when the band offset between the two GLs is aligned. The RT produces a strong nonlinearity with a negative differential conductance in the DGL current-voltage characteristics. The excitation of the graphene plasmons by the THz radiation resonantly modulates the tunneling currentvoltage characteristics. When the band offset is aligned to the THz photon energy, the DGL structure can mediate photonassisted RT, resulting in resonant emission or detection of the THz radiation. The cooperative double-resonant excitation with structure-sensitive graphene plasmons gives rise to various functionalities such as rectification (detection), photomixing, higher harmonic generation, and self-oscillation, in the THz device implementations.

  7. UV Observations of Prominence Activation and Cool Loop Dynamics

    NASA Technical Reports Server (NTRS)

    Kucera, Therese A.; Landi, Enrico

    2006-01-01

    In this paper we investigate the thermal and dynamic properties of dynamic structures in and around a prominence channel observed on the limb on 17 April 2003. Observations were taken with the Solar and Heliospheric Observatory's Solar Ultraviolet Measurements of Emitted Radiation (SOHO/SUMER) in lines formed at temperatures from 80,000 to 1.6 MK. The instrument was pointed to a single location and took a series of 90 s exposures. Two-dimensional context was provided by the Transition Region and Coronal Explorer (TRACE) in the UV and EUV and the Kanzelhohe Solar Observatory in H-alpha. Two dynamic features were studied in depth: an activated prominence and repeated motions in a loop near the prominence. We calculated three-dimensional geometries and trajectories, differential emission measure, and limits on the mass, pressure, average density, and kinetic and thermal energies. These observations provide important tests for models of dynamics in prominences and cool (approx. 10(exp 5) K)loops, which will ultimately lead to a better understanding the mechanism(s) leading to energy and mass flow in these solar features.

  8. MoXy fiber with active cooling cap for bovine prostate vaporization with high power 200W 532 nm laser

    NASA Astrophysics Data System (ADS)

    Peng, Steven Y.; Kang, Hyun Wook; Pirzadeh, Homa; Stinson, Douglas

    2011-03-01

    A novel MoXyTM fiber delivery device with Active Cooling Cap (ACCTM) is designed to transmit up to 180W of 532 nm laser light to treat benign prostatic hyperplasia (BPH). Under such high power tissue ablation, effective cooling is key to maintaining fiber power transmission and ensuring the reliability of the fiber delivery device To handle high power and reduce fiber degradation, the MoXy fiber features a larger core size (750 micrometer) and an internal fluid channel to ensure better cooling of the fiber tip to prevent the cap from burning, detaching, or shattering during the BPH treatment. The internal cooling channel was created with a metal cap and tubing that surrounds the optical fiber. In this study MoXy fibers were used to investigate the effect of power levels of 120 and 200 W on in-vitro bovine prostate ablation using a 532 nm XPSTM laser system. For procedures requiring more than 100 kJ, the MoXy fiber at 200W removed tissue at twice the rate of the current HPS fiber at 120W. The fiber maintained a constant tissue vaporization rate during the entire tissue ablation process. The coagulation at 200W was about 20% thicker than at 120W. In conclusion, the new fibers at 200W doubled the tissue removal rate, maintained vaporization efficiency throughout delivery of 400kJ energy, and induced similar coagulation to the existing HPS fiber at 120W.

  9. Active cooling design for scramjet engines using optimization methods

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J.; Martin, Carl J.; Lucas, Stephen H.

    1988-01-01

    A methodology for using optimization in designing metallic cooling jackets for scramjet engines is presented. The optimal design minimizes the required coolant flow rate subject to temperature, mechanical-stress, and thermal-fatigue-life constraints on the cooling-jacket panels, and Mach-number and pressure contraints on the coolant exiting the panel. The analytical basis for the methodology is presented, and results for the optimal design of panels are shown to demonstrate its utility.

  10. Active cooling design for scramjet engines using optimization methods

    NASA Technical Reports Server (NTRS)

    Scotti, Stephen J.; Martin, Carl J.; Lucas, Stephen H.

    1988-01-01

    A methodology for using optimization in designing metallic cooling jackets for scramjet engines is presented. The optimal design minimizes the required coolant flow rate subject to temperature, mechanical-stress, and thermal-fatigue-life constraints on the cooling-jacket panels, and Mach-number and pressure constraints on the coolant exiting the panel. The analytical basis for the methodology is presented, and results for the optimal design of panels are shown to demonstrate its utility.

  11. UV Chromospheric Activity in Cool, Short-Period Contact Binaries

    NASA Technical Reports Server (NTRS)

    Hrivnak, Bruce J.

    2000-01-01

    We have completed our analysis of the IUE spectra of the short-period contact binary OO Aql. OO Aql is a rare W UMa-type eclipsing binary in which the two solar-type stars may have only recently evolved into contact. The binary has an unusually high mass ratio (0.84), and a relatively long orbital period (0.506 d) for its spectral type (mid-G). Twelve ultraviolet spectra of OO Aql were obtained in 1988 with the IUE satellite, including a series of consecutive observations that cover nearly a complete orbital cycle. Chromospheric activity is studied by means of the Mg II h+k emission at 2800 A. The Mg II emission is found to vary, even when the emission is normalized to the adjacent continuum flux. This variation may be correlated with orbital phase in the 1988 observations. It also appears that the normalized Mg H emission varies with time, as seen in spectra obtained at two different epochs in 1988 and when compared with two spectra obtained several years earlier. The level of chromospheric activity in OO Aql is less than that of other W UMa-type binaries of similar colors, but this is attributed to its early stage of contact binary evolution. Ultraviolet light curves were composed from measurements of the ultraviolet continuum in the spectra. These were analyzed along with visible light curves of OO Aql to determine the system parameters. The large wavelength range in the light curves enabled a well-constrained fit to a cool spot in the system. A paper on these results is scheduled for publication in the February 2001 issue of the Astronomical Journal.

  12. High-Efficiency Solid State Cooling Technologies: Non-Equilibrium Asymmetic Thermoelectrics (NEAT) Devices

    SciTech Connect

    2010-09-01

    BEETIT Project: Sheetak is developing a thermoelectric-based solid state cooling system to replace typical air conditioners that use vapor compression to cool air. With noisy mechanical components, vapor compression systems use a liquid refrigerant to circulate within the air conditioner, absorb heat, and pump the heat out into the external environment. With no noisy moving parts or polluting refrigerants, thermoelectric systems rely on an electrical current being passed through the junction of the two different conducting materials to change temperature. Using advanced semiconductor technology, Sheetak is improving solid state cooling systems by using proprietary thermoelectric materials along with other innovations to achieve significant energy efficiency. Sheetak’s new design displaces compressor-based technology; improves reliability; and decreases energy usage. Sheetak’s use of semiconductor manufacturing methods leads to less material use—facilitating cheaper production.

  13. Antifungal activity of antimicrobial-impregnated devices.

    PubMed

    Darouiche, R O; Mansouri, M D; Kojic, E M

    2006-04-01

    The in-vitro and in-vivo efficacy against Candida albicans and Candida krusei of devices impregnated with chlorhexidine and chloroxylenol was examined. The impregnated devices produced large zones of inhibition against both organisms (mean size, 39 mm and 38 mm, respectively). In a rabbit model in which segments of silicone catheters were placed percutaneously, non-impregnated devices were twice as likely as impregnated devices to become colonised with either C. albicans or C. krusei. Impregnated devices also had significantly lower colony counts of C. albicans (58 vs. 1361 CFU; p 0.008) and C. krusei (19 vs. 764 CFU; p 0.008).

  14. Activity and Kinematics of Cool and Ultracool Dwarfs

    NASA Astrophysics Data System (ADS)

    Schmidt, Sarah Jane

    The ages of cool and ultracool dwarfs are particularly important. For cool M dwarfs, accurate ages combined with their ubiquity in the stellar disk could lead to a new level of precision in age dating the Galaxy. A better understanding of the chromospheres of M dwarfs could provide important clues about the relationship between activity and age in these low mass stars. Ultracool (late-M and L) dwarfs have the distinction of including both warm, young brown dwarfs and stars with mean ages more representative of the stellar disk. Kinematics are a source of mean ages and could provide or confirm discriminating features between stars and brown dwarfs. This thesis is composed of several different projects, each investigating the activity or kinematics of cool or ultracool dwarfs. First, a sample of nearly 500 L dwarfs selected from SDSS DR7 photometry and spectroscopy is examined; we discovered 200 new L dwarfs and found evidence of a bias towards red J - KS colors in the entire population of previously known L dwarfs. Using the three-dimensional kinematics of 300 SDSS DR7 L dwarfs, we find that their kinematics are consistent with those of the stellar disk and include a previously undetected thick disk component. We also confirmed a relationship between age and J - KS color (due to our large sample of UVW motions and unbiased J - KS colors), with blue L dwarfs having hotter kinematics (consistent with older ages) and redder L dwarfs having colder, younger kinematics. The DR7 L dwarf sample showed no distinct kinematic difference between young brown dwarfs and disk-age stars, perhaps due to a bias towards early spectral types. In order to probe the kinematic distribution of L dwarfs in a volume-limited sample, we began a survey of radial velocities of nearby (d<20pc) L dwarfs using the TripleSpec instrument on the ARC 3.5-m telescope at APO. While several reduction packages were tested on the TripleSpec data, none were found to provide reductions of sufficient quality

  15. Active Control of Jets in Cross-Flow for Film Cooling Applications

    NASA Technical Reports Server (NTRS)

    Nikitopoulos, Dimitris E.

    2003-01-01

    Jets in cross-flow have applications in film cooling of gas turbine vanes, blades and combustor liners. Their cooling effectiveness depends on the extent to which the cool jet-fluid adheres to the cooled component surface. Lift-off of the cooling jet flow or other mechanisms promoting mixing, cause loss of cooling effectiveness as they allow the hot "free-stream" fluid to come in contact with the component surface. The premise of this project is that cooling effectiveness can be improved by actively controlling (e.9. forcing, pulsing) the jet flow. Active control can be applied to prevent/delay lift-off and suppress mixing. Furthermore, an actively controlled film-cooling system coupled with appropriate sensory input (e.g. temperature or heat flux) can adapt to spatial and temporal variations of the hot-gas path. Thus, it is conceivable that the efficiency of film-cooling systems can be improved, resulting in coolant fluid economy. It is envisioned that Micro Electro-Mechanical Systems (MEMS) will play a role in the realization of such systems. As a first step, a feasibility study will be conducted to evaluate the concept, identify actuation and sensory elements and develop a control strategy. Part of this study will be the design of a proof-of-concept experiment and collection of necessary data.

  16. Receptor guanylyl cyclase-G is a novel thermosensory protein activated by cool temperatures.

    PubMed

    Chao, Ying-Chi; Chen, Chih-Cheng; Lin, Yuh-Charn; Breer, Heinz; Fleischer, Joerg; Yang, Ruey-Bing

    2015-02-03

    Transmembrane guanylyl cyclases (GCs), with activity regulated by peptide ligands and/or calcium-binding proteins, are essential for various physiological and sensory processes. The mode of activation of the GC subtype GC-G, which is expressed in neurons of the Grueneberg ganglion that respond to cool temperatures, has been elusive. In searching for appropriate stimuli to activate GC-G, we found that its enzymatic activity is directly stimulated by cool temperatures. In this context, it was observed that dimerization/oligomerization of GC-G, a process generally considered as critical for enzymatic activity of GCs, is strongly enhanced by coolness. Moreover, heterologous expression of GC-G in cultured cells rendered these cells responsive to coolness; thus, the protein might be a sensor for cool temperatures. This concept is supported by the observation of substantially reduced coolness-induced response of Grueneberg ganglion neurons and coolness-evoked ultrasonic vocalization in GC-G-deficient mouse pups. GC-G may be a novel thermosensory protein with functional implications for the Grueneberg ganglion, a sensory organ responding to cool temperatures.

  17. Subcontracted activities related to TES for building heating and cooling

    NASA Technical Reports Server (NTRS)

    Martin, J.

    1980-01-01

    The subcontract program elements related to thermal energy storage for building heating and cooling systems are outlined. The following factors are included: subcontracts in the utility load management application area; life and stability testing of packaged low cost energy storage materials; and development of thermal energy storage systems for residential space cooling. Resistance storage heater component development, demonstration of storage heater systems for residential applications, and simulation and evaluation of latent heat thermal energy storage (heat pump systems) are also discussed. Application of thermal energy storage for solar application and twin cities district heating are covered including an application analysis and technology assessment of thermal energy storage.

  18. Subcontracted activities related to TES for building heating and cooling

    NASA Astrophysics Data System (ADS)

    Martin, J.

    1980-03-01

    The subcontract program elements related to thermal energy storage for building heating and cooling systems are outlined. The following factors are included: subcontracts in the utility load management application area; life and stability testing of packaged low cost energy storage materials; and development of thermal energy storage systems for residential space cooling. Resistance storage heater component development, demonstration of storage heater systems for residential applications, and simulation and evaluation of latent heat thermal energy storage (heat pump systems) are also discussed. Application of thermal energy storage for solar application and twin cities district heating are covered including an application analysis and technology assessment of thermal energy storage.

  19. INSERTION DEVICE ACTIVITIES FOR NSLS-II.

    SciTech Connect

    TANABE,T.; HARDER, D.A.; HULBERT, S.; RAKOWSKI, G.; SKARITKA, J.

    2007-06-25

    National Synchrotron Light Source-II (NSLS-II) will be a medium energy storage ring of 3GeV electron beam energy with sub-nm.rad horizontal emittance and top-off capability at 500mA. Damping wigglers will be used not only to reduce the beam emittance but also used as broadband sources for users. Cryo-Permanent Magnet Undulators (CPMUs) are considered for hard X-ray linear device, and permanent magnet based elliptically polarized undulators (EPUs) for variable polarization devices for soft X-ray. 6T superconducting wiggler with minimal fan angle will be installed in the second phase as well as quasi-periodic EPU for VUV and possibly high-temperature superconducting undulator. R&D plans have been established to pursue the performance enhancement of the baseline devices and to design new types of insertion devices. A new insertion device development laboratory will also be established.

  20. Improvement of cooling performance for electronic devices by nucleate boiling of immisible mixtures

    NASA Astrophysics Data System (ADS)

    Okayama, Satoshi; Iwata, Keisuke; Shinmoto, Yasuhisa; Ohta, Haruhiko

    2016-09-01

    The employment of immiscible mixtures in nucleate boiling improves the cooling performance drastically. Increase of CHF is possible by high subcooling of less-volatile liquid compressed by high-vapor pressure of more-volatile component. In addition, the reduction of surface temperature from that of pure less-volatile liquid is resulted from the co-existed vapor of more-volatile component. And the increase of pressure above the atmospheric keeping low liquid temperature is possible to prevent the mixing of incondensable gases. Furthermore, boiling can be initiated at lower surface temperature, which is required for the cooling of e.g. automobile inverters accompanied by large variation of thermal load. The performance of immiscible mixtures in nucleate boiling are summarized with reference to new data for Novec7100/water and FC72/ethanol and existing data obtained by the present authors.

  1. Performance of Scroll-Type Helium Compressor with Oil Injection Cooling Device

    NASA Astrophysics Data System (ADS)

    Shiibayashi, Masao; Tomita, Yoshikatsu; Izunaga, Yasushi; Maeda, Naoki

    In the cryoelectronics field where the helium gas is utilized as a working field, rotary-type and reciprocating-type compressors are popular for the discharge capacity of less than 200Nm3/h and screw-type compressor for a larger capacity. In this study, scroll-type fluid machinery, featuring both high efficiency and high reliability, is applied to a helium compressor with the discharge capacity of 50 Nm3/h. Experimental investigations are performed about oil injection cooling methods and improvement of the compression efficiency. As a result, a volumetric efficiency of 92 % and an overall adiabatic efficiency of 79 % are obtained under the condition of a theoretical compression ratio of 5.2 by a developed scroll compressor with a nominal motor output 2.2 kW. At the same time an effective cooling method with a single oil injection port is obtained.

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

    SciTech Connect

    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.

  3. SHADE: A Shape-Memory-Activated Device Promoting Ankle Dorsiflexion

    NASA Astrophysics Data System (ADS)

    Pittaccio, S.; Viscuso, S.; Rossini, M.; Magoni, L.; Pirovano, S.; Villa, E.; Besseghini, S.; Molteni, F.

    2009-08-01

    Acute post-stroke rehabilitation protocols include passive mobilization as a means to prevent contractures. A device (SHADE) that provides repetitive passive motion to a flaccid ankle by using shape memory alloy actuators could be of great help in providing this treatment. A suitable actuator was designed as a cartridge of approximately 150 × 20 × 15 mm, containing 2.5 m of 0.25 mm diameter NiTi wire. This actuator was activated by Joule’s effect employing a 7 s current input at 0.7 A, which provided 10 N through 76 mm displacement. Cooling and reset by natural convection took 30 s. A prototype of SHADE was assembled with two thermoplastic shells hinged together at the ankle and strapped on the shin and foot. Two actuators were fixed on the upper shell while an inextensible thread connected each NiTi wire to the foot shell. The passive ankle motion (passive range of motion, PROM) generated by SHADE was evaluated optoelectronically on three flaccid patients (58 ± 5 years old); acceptability was assessed by a questionnaire presented to further three flaccid patients (44 ± 11.5 years old) who used SHADE for 5 days, 30 min a day. SHADE was well accepted by all patients, produced good PROM, and caused no pain. The results prove that suitable limb mobilization can be produced by SMA actuators.

  4. A novel head-neck cooling device for concussion injury in contact sports

    PubMed Central

    Wang, Huan; Wang, Bonnie; Jackson, Kevin; Miller, Claire M.; Hasadsri, Linda; Llano, Daniel; Rubin, Rachael; Zimmerman, Jarred; Johnson, Curtis; Sutton, Brad

    2015-01-01

    Emerging research on the long-term impact of concussions on athletes has allowed public recognition of the potentially devastating effects of these and other mild head injuries. Mild traumatic brain injury (mTBI) is a multifaceted disease for which management remains a clinical challenge. Recent pre-clinical and clinical data strongly suggest a destructive synergism between brain temperature elevation and mTBI; conversely, brain hypothermia, with its broader, pleiotropic effects, represents the most potent neuro-protectant in laboratory studies to date. Although well-established in selected clinical conditions, a systemic approach to accomplish regional hypothermia has failed to yield an effective treatment strategy in traumatic brain injury (TBI). Furthermore, although systemic hypothermia remains a potentially valid treatment strategy for moderate to severe TBIs, it is neither practical nor safe for mTBIs. Therefore, selective head-neck cooling may represent an ideal strategy to provide therapeutic benefits to the brain. Optimizing brain temperature management using a National Aeronautics and Space Administration (NASA) spacesuit spinoff head-neck cooling technology before and/or after mTBI in contact sports may represent a sensible, practical, and effective method to potentially enhance recover and minimize post-injury deficits. In this paper, we discuss and summarize the anatomical, physiological, preclinical, and clinical data concerning NASA spinoff head-neck cooling technology as a potential treatment for mTBIs, particularly in the context of contact sports. PMID:28123788

  5. A novel head-neck cooling device for concussion injury in contact sports.

    PubMed

    Wang, Huan; Wang, Bonnie; Jackson, Kevin; Miller, Claire M; Hasadsri, Linda; Llano, Daniel; Rubin, Rachael; Zimmerman, Jarred; Johnson, Curtis; Sutton, Brad

    2015-01-01

    Emerging research on the long-term impact of concussions on athletes has allowed public recognition of the potentially devastating effects of these and other mild head injuries. Mild traumatic brain injury (mTBI) is a multifaceted disease for which management remains a clinical challenge. Recent pre-clinical and clinical data strongly suggest a destructive synergism between brain temperature elevation and mTBI; conversely, brain hypothermia, with its broader, pleiotropic effects, represents the most potent neuro-protectant in laboratory studies to date. Although well-established in selected clinical conditions, a systemic approach to accomplish regional hypothermia has failed to yield an effective treatment strategy in traumatic brain injury (TBI). Furthermore, although systemic hypothermia remains a potentially valid treatment strategy for moderate to severe TBIs, it is neither practical nor safe for mTBIs. Therefore, selective head-neck cooling may represent an ideal strategy to provide therapeutic benefits to the brain. Optimizing brain temperature management using a National Aeronautics and Space Administration (NASA) spacesuit spinoff head-neck cooling technology before and/or after mTBI in contact sports may represent a sensible, practical, and effective method to potentially enhance recover and minimize post-injury deficits. In this paper, we discuss and summarize the anatomical, physiological, preclinical, and clinical data concerning NASA spinoff head-neck cooling technology as a potential treatment for mTBIs, particularly in the context of contact sports.

  6. Cognitive Inference Device for Activity Supervision in the Elderly

    PubMed Central

    2014-01-01

    Human activity, life span, and quality of life are enhanced by innovations in science and technology. Aging individual needs to take advantage of these developments to lead a self-regulated life. However, maintaining a self-regulated life at old age involves a high degree of risk, and the elderly often fail at this goal. Thus, the objective of our study is to investigate the feasibility of implementing a cognitive inference device (CI-device) for effective activity supervision in the elderly. To frame the CI-device, we propose a device design framework along with an inference algorithm and implement the designs through an artificial neural model with different configurations, mapping the CI-device's functions to minimise the device's prediction error. An analysis and discussion are then provided to validate the feasibility of CI-device implementation for activity supervision in the elderly. PMID:25405211

  7. Off-axis cooling of rotating devices using a crank-shaped heat pipe

    DOEpatents

    Jankowski, Todd A.; Prenger, F. Coyne; Waynert, Joseph A.

    2007-01-30

    The present invention is a crank-shaped heat pipe for cooling rotating machinery and a corresponding method of manufacture. The crank-shaped heat pipe comprises a sealed cylindrical tube with an enclosed inner wick structure. The crank-shaped heat pipe includes a condenser section, an adiabatic section, and an evaporator section. The crank-shape is defined by a first curve and a second curve existing in the evaporator section or the adiabatic section of the heat pipe. A working fluid within the heat pipe provides the heat transfer mechanism.

  8. Retrofit device and method to improve humidity control of vapor compression cooling systems

    DOEpatents

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2016-08-16

    A method and device for improving moisture removal capacity of a vapor compression system is disclosed. The vapor compression system is started up with the evaporator blower initially set to a high speed. A relative humidity in a return air stream is measured with the evaporator blower operating at the high speed. If the measured humidity is above the predetermined high relative humidity value, the evaporator blower speed is reduced from the initially set high speed to the lowest possible speed. The device is a control board connected with the blower and uses a predetermined change in measured relative humidity to control the blower motor speed.

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

    NASA Technical Reports Server (NTRS)

    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.

  10. High heat flux actively cooled honeycomb sandwich structural panel for a hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Koch, L. C.; Pagel, L. L.

    1978-01-01

    The results of a program to design and fabricate an unshielded actively cooled structural panel for a hypersonic aircraft are presented. The design is an all-aluminum honeycomb sandwich with embedded cooling passages soldered to the inside of the outer moldline skin. The overall finding is that an actively cooled structure appears feasible for application on a hypersonic aircraft, but the fabrication process is complex and some material and manufacturing technology developments are required. Results from the program are summarized and supporting details are presented.

  11. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    DOEpatents

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  12. Is Performance of Intermittent Intense Exercise Enhanced by Use of a Commercial Palm Cooling Device?

    DTIC Science & Technology

    2009-12-01

    RTX has reported anecdotal evidence of athletes increasing repetitive set training volumes by extremely large amounts when using the device between...characteristics are dis- played in Table 1. All subjects met the American College of Sports Medicine’s low-risk classification (1) for exercise testing...subjects walked at a moderate rate until their HR reached 90% of the predicted maximum , which occurred between 34 and 57 minutes of continuous exercise

  13. Flightweight radiantly and actively cooled panel: thermal and structural performance

    SciTech Connect

    Shore, C.P.; Nowak, R.J.; Kelly, H.N.

    1982-01-01

    A 2- by 4-ft flightweight panel was subjected to thermal/structural tests representative of design flight conditions for a Mach 6.7 transport and to off-design conditions simulating flight maneuvers and cooling system failures. The panel utilized Rene 41 heat shields backed by a thin layer of insulation to radiate away most of the 12 Btu/ft/sup 2/-sec incident heating. A solution of ethylene glycol in water circulating through tubes in an aluminum-honeycomb-sandwich panel absorbed the remainder of the incident heating (0.8 Btu/sq ft-sec). The panel successfully withstood (1) 46.7 hr of radiant heating which included 53 thermal cycles and 5000 cycles of uniaxial inplane loading of + or - 1200 lfb/in; (2) simulated 2g-maneuver heating conditions and simulated cooling system failures without excessive temperatures on the structural panel; and (3) the extensive thermal/structural tests and the aerothermal tests reported in NASA TP-1595 without significant damage to the structural panel, coolant leaks, or hot-gas ingress to the structural panel.

  14. Active cooling solutions for high power laser diodes stacks

    NASA Astrophysics Data System (ADS)

    Karni, Yoram; Klumel, Genady; Levy, Moshe; Berk, Yuri; Openhaim, Yaki; Gridish, Yaakov; Elgali, Asher; Avisar, Meir; Blonder, Moshe; Sagy, Hila; Gertsenshtein, Alex

    2008-02-01

    High power water cooled diode lasers find increasing demand in biomedical, cosmetic and industrial applications, where very high brightness and power are required. The high brightness is achieved either by increasing the power of each bar or by reducing the emitting area of the stacks. Two new products will be presented: Horizontal CW stacks with output power as high as 1kW using 80 W bars with emitting area width as low as 50 μm Vertical QCW stacks with output power as high as 1.2kW using 120 W bars. Heat removal from high power laser stacks often requires microchannel coolers operated with finely filtered deionized (DI) water. However, for certain industrial applications the reliability of this cooling method is widely considered insufficient due to leakage failures caused the highly corrosive DI water. Two solutions to the above problem will be discussed. A microchannel cooler-based package, which vastly reduces the corrosion problem, and a novel high-power laser diode stack that completely eliminates it. The latter solution is especially effective for pulsed applications in high duty cycle range.

  15. Flightweight radiantly and actively cooled panel: Thermal and structural performance

    NASA Technical Reports Server (NTRS)

    Shore, C. P.; Nowak, R. J.; Kelly, H. N.

    1982-01-01

    A 2- by 4-ft flightweight panel was subjected to thermal/structural tests representative of design flight conditions for a Mach 6.7 transport and to off-design conditions simulating flight maneuvers and cooling system failures. The panel utilized Rene 41 heat shields backed by a thin layer of insulation to radiate away most of the 12 Btu/ft2-sec incident heating. A solution of ethylene glycol in water circulating through tubes in an aluminum-honeycomb-sandwich panel absorbed the remainder of the incident heating (0.8 Btu/sq ft-sec). The panel successfully withstood (1) 46.7 hr of radiant heating which included 53 thermal cycles and 5000 cycles of uniaxial inplane loading of + or - 1200 lfb/in; (2) simulated 2g-maneuver heating conditions and simulated cooling system failures without excessive temperatures on the structural panel; and (3) the extensive thermal/structural tests and the aerothermal tests reported in NASA TP-1595 without significant damage to the structural panel, coolant leaks, or hot-gas ingress to the structural panel.

  16. A comparison of the heat transfer capabilities of two manufacturing methods for high heat flux water-cooled devices

    SciTech Connect

    McKoon, R.H.

    1986-10-01

    An experimental program was undertaken to compare the heat transfer characteristics of water-cooled copper devices manufactured via conventional drilled passage construction and via a technique whereby molten copper is cast over a network of preformed cooling tubes. Two similar test blocks were constructed; one using the drilled passage technique, the other via casting copper over Monel pipe. Each test block was mounted in a vacuum system and heated uniformly on the top surface using a swept electron beam. From the measured absorbed powers and resultant temperatures, an overall heat transfer coefficient was calculated. The maximum heat transfer coefficient calculated for the case of the drilled passage test block was 2534 Btu/hr/ft/sup 2///sup 0/F. This corresponded to an absorbed power density of 320 w/cm/sup 2/ and resulted in a maximum recorded copper temperature of 346/sup 0/C. Corresponding figures for the cast test block were 363 Btu/hr/ft/sup 2///sup 0/F, 91 w/cm/sup 2/, and 453/sup 0/C.

  17. Antimicrobial activity of antiseptic-coated orthopaedic devices.

    PubMed

    Darouiche, R O; Green, G; Mansouri, M D

    1998-04-01

    Antimicrobial coating of medical devices, including fracture fixation devices, has evolved as a potentially effective method for preventing device-related infections. We examined the in vitro antimicrobial activity of titanium cylinders coated with the antiseptic combination of chlorhexidine and chloroxylenol. The coated devices provided zones of inhibition against Staphylococcus epidermidis, S. aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans, at baseline and up to 8 weeks after incubation of the coated cylinders in human serum at 37 degrees C. This durable antimicrobial activity was attributed to the relatively slow leaching of chlorhexidine and chloroxylenol from the coated cylinders as measured by high-performance liquid chromatography. These results suggest that antiseptic-coated orthopaedic devices may provide broad-spectrum and durable antimicrobial protection against device-related infection.

  18. Brazing of the Tore Supra actively cooled Phase III Limiter

    SciTech Connect

    Nygren, R.E.; Walker, C.A.; Lutz, T.J.; Hosking, F.M.; McGrath, R.T.

    1993-12-31

    The head of the water-cooled Tore Supra Phase 3 Limiter is a bank of 14 round OFHC copper tubes, curved to fit the plasma radius, onto which several hundred pyrolytic graphite (PG) tiles and a lesser number of carbon fiber composite tiles are brazed. The small allowable tolerances for fitting the tiles to the tubes and mating of compound curvatures made the brazing and fabrication extremely challenging. The paper describes the fabrication process with emphasis on the procedure for brazing. In the fixturing for vacuum furnace brazing, the tiles were each independently clamped to the tube with an elaborate set of window frame clamps. Braze quality was evaluated with transient heating tests. Some rebrazing was necessary.

  19. Fail-safe system for activity cooled supersonic and hypersonic aircraft. [using liquid hydrogen fuel

    NASA Technical Reports Server (NTRS)

    Jones, R. A.; Braswell, D. O.; Richie, C. B.

    1975-01-01

    A fail-safe-system concept was studied as an alternative to a redundant active cooling system for supersonic and hypersonic aircraft which use the heat sink of liquid-hydrogen fuel for cooling the aircraft structure. This concept consists of an abort maneuver by the aircraft and a passive thermal protection system (TPS) for the aircraft skin. The abort manuever provides a low-heat-load descent from normal cruise speed to a lower speed at which cooling is unnecessary, and the passive TPS allows the aircraft skin to absorb the abort heat load without exceeding critical skin temperature. On the basis of results obtained, it appears that this fail-safe-system concept warrants further consideration, inasmuch as a fail-safe system could possibly replace a redundant active cooling system with no increase in weight and would offer other potential advantages.

  20. MMIC devices for active phased array antennas

    NASA Technical Reports Server (NTRS)

    Mittra, R.

    1985-01-01

    Considerable progress has been made in the calculation and measurement of the scattering parameters of printed circuit discontinuities. These discontinuities occur in a variety of structures, such as transitions between rectangular waveguide and printed circuits, junctions between circuits of different dielectric constants, and filters and impedance matching circuits. Because of the variety of devices in which these discontinuities occur, it is very useful to understand them in as great a detail as possible. Both theoretical and experimental studies of discontinuities were considered. The theoretical studies have focused on finding ways to predict the scattering from discontinuities. The experimental studies have concentrated on developing measurement techniques for determining the scattering parameters of these discontinuities.

  1. Open active cloaking and illusion devices for the Laplace equation

    NASA Astrophysics Data System (ADS)

    Ma, Qian; Yang, Fan; Jin, Tian Yu; Lei Mei, Zhong; Cui, Tie Jun

    2016-04-01

    We propose open active cloaking and illusion devices for the Laplace equation. Compared with the closed configurations of active cloaking and illusion devices, we focus on improving the distribution schemes for the controlled sources, which do not have to surround the protected object strictly. Instead, the controlled sources can be placed in several small discrete clusters, and produce the desired voltages along the controlled boundary, to actively hide or disguise the protected object. Numerical simulations are performed with satisfactory results, which are further validated by experimental measurements. The open cloaking and illusion devices have many advantages over the closed configurations in various potential applications.

  2. Influence of cooling rate on activity of ionotropic glutamate receptors in brain slices at hypothermia.

    PubMed

    Mokrushin, Anatoly A; Pavlinova, Larisa I; Borovikov, Sergey E

    2014-08-01

    Hypothermia is a known approach in the treatment of neurological pathologies. Mild hypothermia enhances the therapeutic window for application of medicines, while deep hypothermia is often accompanied by complications, including problems in the recovery of brain functions. The purpose of present study was to investigate the functioning of glutamate ionotropic receptors in brain slices cooled with different rates during mild, moderate and deep hypothermia. Using a system of gradual cooling combined with electrophysiological recordings in slices, we have shown that synaptic activity mediated by the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and N-methyl-D-aspartate receptors in rat olfactory cortex was strongly dependent on the rate of lowering the temperature. High cooling rate caused a progressive decrease in glutamate receptor activity in brain slices during gradual cooling from mild to deep hypothermia. On the contrary, low cooling rate slightly changed the synaptic responses in deep hypothermia. The short-term potentiation may be induced in slices by electric tetanization at 16 °C in this case. Hence, low cooling rate promoted preservation of neuronal activity and plasticity in the brain tissue.

  3. A novel thermoelectric cooling device using Peltier modules for inducing local hypothermia of the spinal cord: the effect of local electrically controlled cooling for the treatment of spinal cord injuries in conscious rats.

    PubMed

    Morizane, Kei; Ogata, Tadanori; Morino, Tadao; Horiuchi, Hideki; Yamaoka, Gotaro; Hino, Masayuki; Miura, Hiromasa

    2012-03-01

    We developed a novel thermoelectric cooling device using Peltier modules for the treatment of spinal cord injury in rats. The extracorporeal electrically cooling component was attached to the aluminum arched plate which was placed on the surface of the spinal cord after the contusion injury in the 11th thoracic spinal cord. During the hypothermic treatment, rats were awake and could move in the cage. Hind limb motor function, evaluated using a BBB scale, in the hypothermic animals (33°C for 48 h) was significantly higher than that in the normothermic animals from 2 weeks to 8 weeks after the injury.

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

    SciTech Connect

    Koski, J.A.; Wix, S.D.

    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.

  5. Toward Wearable Cooling Devices: Highly Flexible Electrocaloric Ba0.67 Sr0.33 TiO3 Nanowire Arrays.

    PubMed

    Zhang, Guangzu; Zhang, Xiaoshan; Huang, Houbing; Wang, Jianjun; Li, Qi; Chen, Long-Qing; Wang, Qing

    2016-06-01

    Flexible lead-free ferroelectric ceramic nanowire arrays exhibit a unique combination of features that can contribute to the realization of wearable cooling devices, including an outstanding electrocaloric effect at low fields, high efficiency, bendability and stretchability, and robustness against mechanical deformations. Thermodynamic and phase-field simulations are carried out to validate their superior electrocaloric effect in comparison to thin films.

  6. Development of high-performance cooling devices for space application by using flow boiling in narrow channels.

    PubMed

    Miura, Shinichi; Inada, Yukihiro; Shinmoto, Yasuhisa; Ohta, Haruhiko

    2009-04-01

    Heat generation density from semiconductor devices has been increasing with the rapid development of electronic technology. The cooling system using boiling two-phase phenomena has attracted much attention because of its high heat removal potential. To develop compact and high-performance cooling systems, we conducted experiments on the increase of critical heat flux (CHF) for flow boiling in narrow channels by improved liquid supply. A large surface of 150 mm in heated length and 30 mm in width with grooves of an apex angle of 90 degrees , 0.5-mm depth, and 1 mm in pitch was employed. A structure of narrow heated channel between parallel plates with an unheated auxiliary channel was devised and tested by using water for different combinations of gap sizes and volumetric flow rates, where inlet of the main heated channel and the outlet of auxiliary unheated channel were closed to prevent the flow instability observed frequently at low flow rate for parallel two channels. For the total volumetric flow rate more than 4.5 x 10(-5) m(3)/s, higher values of CHF large than 2 x 10(6) W/m(2) were obtained for gap size of 2 mm. For gap sizes of 2 mm and 5 mm at high volumetric flow rate larger than 6.0 x 10(-5) m(3)/s, or mass velocity based on the cross section are of main heated channel 958.1 kg/m(2)s and 383.2 kg/m(2) s, respectively, the extension of dry patches was observed at the upstream location of the main heated channel resulting in burnout not at the downstream but at the upstream. By the increase in total volumetric flow rate, the pressure drop increased because of increasing in the flow rate passing through the sintered metal porous plates connecting both channels. The values of pressure drop for gap size of 2 mm were higher than that for gap size of 5 mm. When the performance of the cooling system was evaluated on the basis of pump power, ignoring its variation in the efficiency with volumetric flow rate, that is, the power defined as the product of the

  7. Development of novel active transport membrande devices

    SciTech Connect

    Laciak, D.V.

    1994-11-01

    Air Products has undertaken a research program to fabricate and evaluate gas separation membranes based upon promising ``active-transport`` (AT) materials recently developed in our laboratories. Active Transport materials are ionic polymers and molten salts which undergo reversible interaction or reaction with ammonia and carbon dioxide. The materials are useful for separating these gases from mixtures with hydrogen. Moreover, AT membranes have the unique property of possessing high permeability towards ammnonia and carbon dioxide but low permeability towards hydrogen and can thus be used to permeate these components from a gas stream while retaining hydrogen at high pressure.

  8. Heat transfer model to characterize the focal cooling necessary to suppress spontaneous epileptiform activity (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Guerra, Reynaldo G.; Davalos, Rafael V.; Garcia, Paul A.; Rubinsky, Boris; Berger, Mitchel

    2005-04-01

    Epilepsy is characterized by paroxysmal transient disturbances of the electrical activity of the brain. Symptoms are manifested as impairment of motor, sensory, or psychic function with or without loss of consciousness or convulsive seizures. This paper presents an initial post-operative heat transfer analysis of surgery performed on a 41 year-old man with medically intractable Epilepsy. The surgery involved tumor removal and the resection of adjacent epileptogenic tissue. Electrocorticography was performed before resection. Cold saline was applied to the resulting interictal spike foci resulting in transient, complete cessation of spiking. A transient one dimensional semi-infinite finite element model of the surface of the brain was developed to simulate the surgery. An approximate temperature distribution of the perfused brain was developed by applying the bioheat equation. The model quantifies the surface heat flux reached in achieving seizure cessation to within an order of magnitude. Rat models have previously shown that the brain surface temperature range to rapidly terminate epileptogenic activity is 20-24°C. The developed model predicts that a constant heat flux of approximately -13,000W/m2, applied at the surface of the human brain, would achieve a surface temperature in this range in approximately 3 seconds. A parametric study was subsequently performed to characterize the effects of brain metabolism and brain blood perfusion as a function of the determined heat flux. The results of these findings can be used as a first approximation in defining the specifications of a cooling device to suppress seizures in human models.

  9. Thermal design for areas of interference heating on actively cooled hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Herring, R. L.; Stone, J. E.

    1978-01-01

    Numerous actively cooled panel design alternatives for application in regions on high speed aircraft that are subject to interference heating effects were studied. Candidate design concepts were evaluated using mass, producibility, reliability and inspectability/maintainability as figures of merit. Three design approaches were identified as superior within certain regimes of the matrix of design heating conditions considered. Only minor modifications to basic actively cooled panel design are required to withstand minor interference heating effects. Designs incorporating internally finned coolant tubes to augment heat transfer are recommended for moderate design heating conditions. At severe heating conditions, an insulated panel concept is required.

  10. Study of fail-safe abort system for an actively cooled hypersonic aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Peeples, M. E.; Herring, R. L.

    1976-01-01

    Conceptual designs of a fail-safe abort system for hydrogen fueled actively cooled high speed aircraft are examined. The fail-safe concept depends on basically three factors: (1) a reliable method of detecting a failure or malfunction in the active cooling system, (2) the optimization of abort trajectories which minimize the descent heat load to the aircraft, and (3) fail-safe thermostructural concepts to minimize both the weight and the maximum temperature the structure will reach during descent. These factors are examined and promising approaches are evaluated based on weight, reliability, ease of manufacture and cost.

  11. Geometric investigation of a gaming active device

    NASA Astrophysics Data System (ADS)

    Menna, Fabio; Remondino, Fabio; Battisti, Roberto; Nocerino, Erica

    2011-07-01

    3D imaging systems are widely available and used for surveying, modeling and entertainment applications, but clear statements regarding their characteristics, performances and limitations are still missing. The VDI/VDE and the ASTME57 committees are trying to set some standards but the commercial market is not reacting properly. Since many new users are approaching these 3D recording methodologies, clear statements and information clarifying if a package or system satisfies certain requirements before investing are fundamental for those users who are not really familiar with these technologies. Recently small and portable consumer-grade active sensors came on the market, like TOF rangeimaging cameras or low-cost triangulation-based range sensor. A quite interesting active system was produced by PrimeSense and launched on the market thanks to the Microsoft Xbox project with the name of Kinect. The article reports the geometric investigation of the Kinect active sensors, considering its measurement performances, the accuracy of the retrieved range data and the possibility to use it for 3D modeling application.

  12. Design and fabrication of a skin stringer discrete tube actively cooled structural panel

    NASA Technical Reports Server (NTRS)

    Anthony, F. M.

    1978-01-01

    The design optimization and practical implementation of actively cooled structural panel concepts was investigated. The desired actively cooled structural panel consisted of the cooled skin and a substructure. The primary load carrying components were fabricated from 2024-T3 aliminum alloy. The 3003-H14 coolant passage tubing was chosen because of its excellent corrosion resistance, workability needed to obtain the desired cross sectional shape, and strength. The Epon 951 adhesive was selected for its excellent structural properties and is the thinnest of available films, 0.064 mm. The Eccobond 58C silver filled epoxy was chosen because of its high thermal conductivity, and the alumina filled Epon 828 was chosen for structural and expansion characteristics.

  13. Thermal design and development of actively cooled brushes for compact homopolar generators

    NASA Astrophysics Data System (ADS)

    Makel, D. B.

    1986-11-01

    The thermal and hydraulic design of actively cooled current transfer brushes for compact homopolar generators (HPG) is described. The development of high-energy-density HPG's at the Center for Electromechanics at the University of Texas at Austin requires brushgear capable of handling high current densities and large thermal loads. Platelet technology has been applied in the design of actively cooled brushes with coolant injection directly from the brush contact face into the brush-rotor interface. Coolant channels a few thousandths of an inch in diameter have been designed in brushes constructed of photoetched platelets of copper (0.020 to 0.005 in. thick) and then bonded to form the cooled brush. Platelet construction of brushes also permits the incorporation of internal instrumentation for temperature measurement. The brushes have been designed to provide data on the effects of rotor speed, current level, coolant flow rate, and coolant injection pattern.

  14. Evidence for Widespread Cooling in an Active Region Observed with the SDO Atmospheric Imaging Assembly

    NASA Technical Reports Server (NTRS)

    Viall, Nicholeen M.; Klimchuk, James A.

    2012-01-01

    A well known behavior of EUV light curves of discrete coronal loops is that the peak intensities of cooler channels or spectral lines are reached at progressively later times. This time lag is understood to be the result of hot coronal loop plasma cooling through these lower respective temperatures. However, loops typically comprise only a minority of the total emission in active regions. Is this cooling pattern a common property of active region coronal plasma, or does it only occur in unique circumstances, locations, and times? The new SDO/AIA data provide a wonderful opportunity to answer this question systematically for an entire active region. We measure the time lag between pairs of SDO/AIA EUV channels using 24 hours of images of AR 11082 observed on 19 June 2010. We find that there is a time-lag signal consistent with cooling plasma, just as is usually found for loops, throughout the active region including the diffuse emission between loops for the entire 24 hour duration. The pattern persists consistently for all channel pairs and choice of window length within the 24 hour time period, giving us confidence that the plasma is cooling from temperatures of greater than 3 MK, and sometimes exceeding 7 MK, down to temperatures lower than approx. 0.8 MK. This suggests that the bulk of the emitting coronal plasma in this active region is not steady; rather, it is dynamic and constantly evolving. These measurements provide crucial constraints on any model which seeks to describe coronal heating.

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

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

    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

  17. Localized cooling of stems induces latewood formation and cambial dormancy during seasons of active cambium in conifers

    PubMed Central

    Begum, Shahanara; Kudo, Kayo; Matsuoka, Yugo; Nakaba, Satoshi; Yamagishi, Yusuke; Nabeshima, Eri; Rahman, Md Hasnat; Nugroho, Widyanto Dwi; Oribe, Yuichiro; Jin, Hyun-O; Funada, Ryo

    2016-01-01

    Background and Aims In temperate regions, trees undergo annual cycles of cambial growth, with periods of cambial activity and dormancy. Environmental factors might regulate the cambial growth, as well as the development of cambial derivatives. We investigated the effects of low temperature by localized cooling on cambial activity and latewood formation in two conifers, Chamaecyparis obtusa and Cryptomeria japonica. Methods A plastic rubber tube that contained cooled water was wrapped around a 30-cm-wide portion of the main stem of Chamaecyparis obtusa and Cryptomeria japonica trees during seasons of active cambium. Small blocks were collected from both cooled and non-cooled control portions of the stems for sequential observations of cambial activity and for anatomical measurements of cell morphology by light microscopy and image analysis. Key Results The effect of localized cooling was first observed on differentiating tracheids. Tracheids narrow in diameter and with significantly decreased cambial activity were evident 5 weeks after the start of cooling in these stems. Eight weeks after the start of cooling, tracheids with clearly diminished diameters and thickened cell walls were observed in these stems. Thus, localized low temperature induced narrow diameters and obvious thickening of secondary cell walls of tracheids, which were identified as latewood tracheids. Two months after the cessation of cooling, a false annual ring was observed and cambium became active again and produced new tracheids. In Cryptomeria japonica, cambial activity ceased earlier in locally cooled portions of stems than in non-cooled stems, indicating that the cambium had entered dormancy sooner in the cooled stems. Conclusions Artificial cooling of stems induced latewood formation and cessation of cambial activity, indicating that cambium and its derivatives can respond directly to changes in temperature. A decrease in the temperature of the stem is a critical factor in the control of

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

    NASA Technical Reports Server (NTRS)

    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.

  19. Current Status of Joint AFRL/NASA Microgravity Spray Cooling Research Activities

    NASA Technical Reports Server (NTRS)

    Michalak, Travis; Yerkes,Kirk; McQuillen, John; Golliher, Eric

    2004-01-01

    The Air Force Research Lab and the NASA Glenn Research Center are cooperatively examining spray cooling in a low and a variable gravity environment by conducting experiments principally aboard the NASA Reduced Gravity Aircraft. The objective of these research activities is to examine an effective high-heat flux, high-power thermal management technology using spray cooling for both aircraft and space-based platforms. Previous studies have demonstrated that two phase heat transfer and fluid management are issues that need to be examined. This effort has obtained preliminary results which confirm these concerns. More research is planned.

  20. Active MMI devices: concept, proof, and recent progress

    NASA Astrophysics Data System (ADS)

    Hamamoto, Kiichi; Jiang, Haisong

    2015-09-01

    Multi-mode interference (MMI) couplers (waveguides) are widely studied and developed as key components of photonic integrated circuits, including power coupler/dividers, and others. Furthermore, another possibility utilizing MMI has been investigated on active devices so far. Owing to the wider area of the multi-mode waveguide section compared with that of the regular single-mode waveguide, MMI may result in higher performance (high power, low power consumption, and others) rather than conventional active devices while maintaining regular single-mode output. Thus, active multi-mode interferometer (active-MMI) devices, including laser diodes (LDs), super-luminescent light emitting diodes (SLEDs), and semiconductor optical amplifiers (SOAs) have been studied. Moreover, they have been also exploited to bi-stable LDs and single wavelength emitters, and others using the interference inside the MMI section. In this paper, we review and summarize the recent progress in active MMI devices. We provide proof of MMI phenomena in active waveguides and discuss the results.

  1. Human paranasal sinuses and selective brain cooling: a ventilation system activated by yawning?

    PubMed

    Gallup, Andrew C; Hack, Gary D

    2011-12-01

    The function of the paranasal sinuses has been a controversial subject since the time of Galen, with many different theories advanced about their biological significance. For one, the paranasal sinuses have been regarded as warmers of respiratory air, when in actuality these structures appear to function in cooling the blood. In fact, human paranasal sinuses have been shown to have higher volumes in individuals living in warmer climates, and thus may be considered radiators of the brain. The literature suggests that the transfer of cool venous blood from the paranasal sinuses to the dura mater may provide a mechanism for the convection process of cooling produced by the evaporation of mucus within human sinuses. In turn, the dura mater may transmit these temperature changes, initiated by the cool venous blood from the heat-dissipating surfaces of the sinuses, to the cerebrospinal fluid compartments. Furthermore, it has recently been demonstrated in cadaveric dissections that the thin bony posterior wall of the maxillary sinus serves as an origin for both medial and lateral pterygoid muscle segments, an anatomic finding that had been previously underappreciated in the literature. The present authors hypothesize that the thin posterior wall of the maxillary sinus may flex during yawning, operating like a bellows pump, actively ventilating the sinus system, and thus facilitating brain cooling. Such a powered ventilation system has not previously been described in humans, although an analogous system has been reported in birds.

  2. Continuous sorption cooling in activated carbon-nitrogen system using metal foam as regenerator

    NASA Astrophysics Data System (ADS)

    Ghosh, Indranil

    2017-02-01

    In compressor driven solid sorption process, cooling obtained from a desorbing bed (equivalent to an evaporator), is intermittent in nature. Intermittency can be avoided using multiple adsorbent columns. However, connecting a desorbing bed to heat source and adsorbing beds to heat sink in alternate cycles enhances operational complexity and constructional disadvantages. In a recent development, it has been seen that rapid and successive pressurization and depressurization of an adsorbent (solid) bed with adsorbate (gas) creates temperature differential across the column length. The presence of an orifice at the end opposite to gas entrance enhances the temperature gradient. By connecting the hot end to heat sink and the cold end to heat source permanently, one can substantially reduce the operational hazards associated with the intermittent sorption cooling processes. More recently, it has seen that the introduction of a regenerator in the process makes the cooling process more effective. Though the proposed sorption cooling process apparently looks similar to orifice type ‘pulse tube’ cooler, the former is intrinsically different than the other. In the present manuscript, experimental sorption cooling studies using of metal foam as regenerator has been discussed. Tests have been conducted near room temperature in activated carbon-nitrogen system.

  3. Active cooling in traumatic brain-injured patients: a questionable therapy?

    PubMed

    Grände, P-O; Reinstrup, P; Romner, B

    2009-11-01

    Hypothermia is shown to be beneficial for the outcome after a transient global brain ischaemia through its neuroprotective effect. Whether this is also the case after focal ischaemia, such as following a severe traumatic brain injury (TBI), has been investigated in numerous studies, some of which have shown a tendency towards an improved outcome, whereas others have not been able to demonstrate any beneficial effect. A Cochrane report concluded that the majority of the trials that have already been published have been of low quality, with unclear allocation concealment. If only high-quality trials are considered, TBI patients treated with active cooling were more likely to die, a conclusion supported by a recent high-quality Canadian trial on children. Still, there is a belief that a modified protocol with a shorter time from the accident to the start of active cooling, longer cooling and rewarming time and better control of blood pressure and intracranial pressure would be beneficial for TBI patients. This belief has led to the instigation of new trials in adults and in children, including these types of protocol adjustments. The present review provides a short summary of our present knowledge of the use of active cooling in TBI patients, and presents some tentative explanations as to why active cooling has not been shown to be effective for outcome after TBI. We focus particularly on the compromised circulation of the penumbra zone, which may be further reduced by the stress caused by the difference in thermostat and body temperature and by the hypothermia-induced more frequent use of vasoconstrictors, and by the increased risk of contusional bleedings under hypothermia. We suggest that high fever should be reduced pharmacologically.

  4. Actively cooled plasma electrode for long pulse operations in a cesium-seeded negative ion source

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yukio; Watanabe, Kazuhiro; Okumura, Yoshikazu; Trainham, Rusty; Jacquot, Claude

    2005-01-01

    An actively cooled plasma electrode has been developed for long pulse operation in a cesium-seeded negative ion source. To keep the electrode temperature at about 300°C, which is the optimum range of temperature to enhance cesium effects, the electrode cooling structure has been designed using three-dimensional numerical simulation assuming that the heat flux from the source plasma was 15W/cm2. Water cooling tubes were brazed to the plasma electrode substrate with spacers made of stainless steel, which acts as a thermal resistance. The fabricated plasma electrode has been tested in a cesium-seeded volume negative ion source called Kamaboko source. The temperature of the electrode reached 280°C for the arc power of 41kW, which is the operating condition required for producing D- beams with current densities exceeding 20mA/cm2. It was demonstrated that the actively cooled plasma electrode is applicable to long pulse operations, meeting the temperature requirement for optimizing the surface-production process of negative ions in the cesium-seeded ion source.

  5. Active versus passive cooling during work in warm environments while wearing firefighting protective clothing.

    PubMed

    Selkirk, G A; McLellan, T M; Wong, J

    2004-08-01

    This study examined whether active or passive cooling during intermittent work reduced the heat strain associated with wearing firefighting protective clothing (FPC) and self-contained breathing apparatus (SCBA) in the heat (35 degrees Celsius, 50% relative humidity). Fifteen male Toronto firefighters participated in the heat-stress trials. Subjects walked at 4.5 km.h(-1) with 0% elevation on an intermittent work (50 min) and rest (30 min) schedule. Work continued until rectal temperature (T(re)) reached 39.5 degrees Celsius, or heart rate (HR) reached 95% of maximum or exhaustion. One of three cooling strategies, forearm submersion (FS), mister (M), and passive cooling (PC) were employed during the rest phases. Tolerance time (TT) and total work time (WT) (min) were significantly increased during FS (178.7 +/- 13.0 and 124.7 +/- 7.94, respectively) and M (139.1 +/- 8.28 and 95.1 +/- 4.96, respectively), compared with PC (108.0 +/- 3.59 and 78.0 +/- 3.59). Furthermore, TT and WT were significantly greater in FS compared with M. Rates of T(re) increase, HR and T-(sk) were significantly lower during active compared with passive cooling. In addition, HR and T(re) values in FS were significantly lower compared with M after the first rest phase. During the first rest phase, T(re) dropped significantly during FS (approximately 0.4 degree Celsius) compared with M (approximately 0.08 degree Celsius) while PC increased (approximately 0.2 degree Celsius). By the end of the second rest period T(re) was 0.9 degree Celsius lower in FS compared with M. The current findings suggest that there is a definite advantage when utilizing forearm submersion compared with other methods of active or passive cooling while wearing FPC and SCBA in the heat.

  6. Laser-activated shape memory polymer intravascular thrombectomy device

    NASA Astrophysics Data System (ADS)

    Small, Ward, IV; Wilson, Thomas S.; Benett, William J.; Loge, Jeffrey M.; Maitland, Duncan J.

    2005-10-01

    A blood clot (thrombus) that becomes lodged in the arterial network supplying the brain can cause an ischemic stroke, depriving the brain of oxygen and often resulting in permanent disability. As an alternative to conventional clot-dissolving drug treatment, we are developing an intravascular laser-activated therapeutic device using shape memory polymer (SMP) to mechanically retrieve the thrombus and restore blood flow to the brain. Thermal imaging and computer simulation were used to characterize the optical and photothermal behavior of the SMP microactuator. Deployment of the SMP device in an in vitro thrombotic vascular occlusion model demonstrated the clinical treatment concept.

  7. Active cooling-based surface confinement system for thermal soil treatment

    DOEpatents

    Aines, Roger D.; Newmark, Robin L.

    1997-01-01

    A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders.

  8. Active cooling-based surface confinement system for thermal soil treatment

    DOEpatents

    Aines, R.D.; Newmark, R.L.

    1997-10-28

    A thermal barrier is disclosed for surface confinement with active cooling to control subsurface pressures during thermal remediation of shallow (5-20 feet) underground contaminants. If steam injection is used for underground heating, the actively cooled thermal barrier allows the steam to be injected into soil at pressures much higher (20-60 psi) than the confining strength of the soil, while preventing steam breakthrough. The rising steam is condensed to liquid water at the thermal barrier-ground surface interface. The rapid temperature drop forced by the thermal barrier drops the subsurface pressure to below atmospheric pressure. The steam and contaminant vapors are contained by the thermal blanket, which can be made of a variety of materials such as steel plates, concrete slabs, membranes, fabric bags, or rubber bladders. 1 fig.

  9. National commercial solar heating and cooling demonstration: purposes, program activities, and implications for future programs

    SciTech Connect

    Koontz, R.; Genest, M.; Bryant, B.

    1980-05-01

    The Solar Heating and Cooling Demonstration Act of 1974 created a set of activities to demonstrate the potential use of solar heating within a three-year period and of combined solar heating and cooling within a five-year period. This study assesses the Commercial Demonstration Program portion of the activity in terms of its stated goals and objectives. The primary data base was DOE contractor reports on commercial demonstration projects. It was concluded that the program did not provide data to support a positive decision for the immediate construction or purchase of commercial solar systems. However, the program may have contributed to other goals in the subsequent legislation; i.e., research and development information, stimulation of the solar industry, and more informed policy decisions.

  10. Fabrication and Characterization of Brush-Printed p-Type Bi0.5Sb1.5Te3 Thick Films for Thermoelectric Cooling Devices

    NASA Astrophysics Data System (ADS)

    Wu, Han; Liu, Xing; Wei, Ping; Zhou, Hong-Yu; Mu, Xin; He, Dan-Qi; Zhu, Wan-Ting; Nie, Xiao-Lei; Zhao, Wen-Yu; Zhang, Qing-Jie

    2016-11-01

    Bismuth telluride alloys are promising thermoelectric materials used for portable and wearable cooling devices due to their excellent thermoelectric properties near the ambient temperature. Here, a simple and cost-effective brush-printing technique, together with a subsequent annealing treatment, has been used to prepare Bi2Te3-based thick films and prototype devices. The composition, microstructure, and electrical properties of the brush-printed p-type Bi0.5Sb1.5Te3 thick films at different annealing temperatures are investigated. It is found that annealing temperature plays an important role in promoting densification and preventing the film from cracking, hence improving the electrical transport properties. The maximum power factor of the brush-printed thick films is 0.15 mW K-2 m-1 when annealed at 673 K for 4 h. A prototype thermoelectric device is manufactured by connecting the brush-printed p-type Bi0.5Sb1.5Te3 and n-type Bi2Te2.7Se0.3 thick films with Cu thick-film electrodes on an Al2O3 substrate. The cooling performance of the thermoelectric device is evaluated by measuring the temperature difference produced under applied currents.

  11. Active cooling for downhole instrumentation: design criteria and conceptual design summary

    SciTech Connect

    Bennett, G.A.

    1986-05-01

    This report summarizes the results of a literature survey that describes successful tests of geophysical instruments and their thermal protection systems. The conditions to which an instrument is subjected are formulated into relevant thermal and mechanical design criteria that have proved useful for improving passive thermal protection systems and selecting the preliminary feasibility of active refrigeration systems. A brief summary of the results of a series of conceptual designs on seven different active refrigeration systems is given. The systems are ranked according to feasibility for use in downhole active cooling applications.

  12. Grueneberg Glomeruli in the Olfactory Bulb are Activated by Odorants and Cool Temperature.

    PubMed

    Bumbalo, Rosolino; Lieber, Marilena; Schroeder, Lisa; Polat, Yasemin; Breer, Heinz; Fleischer, Joerg

    2016-08-03

    Neurons of the Grueneberg ganglion respond to cool temperatures as well as to distinct odorants and extend axonal processes to the olfactory bulb of the brain. Analyses of transgenic mice, in which Grueneberg ganglion neurons and their axons are labeled, revealed that these axons innervated nine distinct glomeruli distributed in a characteristic topographical pattern in dorsal, lateral, ventral, and medial regions of rather posterior areas in the bulb. To assess activation of these glomeruli (hereinafter designated as Grueneberg glomeruli) upon stimulation of Grueneberg ganglion neurons, mice were exposed to the odorant 2,3-dimethylpyrazine (2,3-DMP) and the expression of the activity-dependent marker c-Fos in juxtaglomerular cells of the relevant glomeruli was monitored. It was found that all of these glomeruli were activated, irrespective of their localization in the bulb. To verify that the activation of juxtaglomerular cells in Grueneberg glomeruli was indeed based on stimulation of Grueneberg ganglion neurons, the 2,3-DMP-induced responses in these glomeruli were investigated in mice lacking the cyclic nucleotide-gated channel CNGA3 which is critical for chemo- and thermosensory signal transduction in Grueneberg ganglion neurons. This approach revealed that elimination of CNGA3 led to a reduction of the odorant-induced activity in Grueneberg glomeruli, indicating that the activation of these glomeruli is based on a preceding stimulation of the Grueneberg ganglion. Analyzing whether Grueneberg glomeruli in the bulb might also process thermosensory information, it was found that upon exposure to coolness, Grueneberg glomeruli were activated. Investigating mice lacking CNGA3, the activation of these glomeruli by cool temperatures was attenuated.

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

    USGS Publications Warehouse

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

    2011-01-01

    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; 1δ 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 H2O 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.

  14. Pharmacokinetics of recombinant human growth hormone administered by cool.click™ 2, a new needle-free device, compared with subcutaneous administration using a conventional syringe and needle

    PubMed Central

    Brearley, Chris; Priestley, Anthony; Leighton-Scott, James; Christen, Michel

    2007-01-01

    Background Growth hormone (GH) is used to treat growth hormone deficiency (GHD, adult and paediatric), short bowel syndrome in patients on a specialized diet, HIV-associated wasting and, in children, growth failure due to a number of disorders including Turner's syndrome and chronic renal failure, and in children born small for gestational age. Different brands and generic forms of recombinant human growth hormone (r-hGH) are approved for varying indications in different countries. New ways of administering GH are required because the use of a needle and syringe or a device where a patient still has to insert the needle manually into the skin on a daily basis can lead to low adherence and sub-optimal treatment outcomes. The objective of this study was to assess the relative bioavailability of r-hGH (Saizen®, Merck Serono) administered by a new needle-free device, cool.click™ 2, and a standard needle and syringe. Methods The study was performed with 38 healthy volunteers who underwent pituitary somatotrope cell down-regulation using somatostatin, according to a randomized, two-period, two-sequence crossover design. Following subcutaneous administration of r-hGH using cool.click™ 2 or needle and syringe, pharmacokinetic parameters were analysed by non-compartmental methods. Bioequivalence was assessed based on log-transformed AUC and Cmax values. Results The 90% confidence intervals for test/reference mean ratio of the plasma pharmacokinetic variables Cmax and AUC0-inf were 103.7–118.3 and 97.1–110.0, respectively, which is within the accepted bioequivalence range of 80–125%. r-hGH administered by cool.click™ 2 is, therefore, bioequivalent to administration by needle and syringe with respect to the rate and extent of GH exposure. Treatment using cool.click™ 2 was found to be well tolerated. With cool.click™ 2 the tmax was less (3.0 hours) than for needle and syringe delivery (4.5 hours), p = 0.002 (Friedman test), although this is unlikely to have

  15. Multi-band terahertz active device with complementary metamaterial

    SciTech Connect

    Qiao, Shen; Zhang, Yaxin Sun, Linlin; Sun, Han; Xu, Gaiqi; Zhao, Yuncheng; Yang, Ziqiang; Liang, Shixiong

    2015-09-28

    We describe a multi-band terahertz-active device using a composite structure made of complementary metamaterial and doped silicon that can be dynamically controlled. This special complementary metamaterial exhibits three resonances that produce three pass-bands. The pass-bands can be uniformly manipulated by exploiting the photoinduced characteristics of the doped silicon. Simulations were performed to analyze the magnetic field and surface current distributions. The simulation results agree well with experimental results obtained from terahertz time-domain spectroscopy. Using an 808-nm-wavelength laser beam, a modulation depth of up to 80% was obtained. In numerical simulations, we used a conductivity mode to characterize photoinduction. The development of multi-band terahertz-active devices has many potential applications, for example, in filters, modulators, switches, and sensors.

  16. Wireless device for activation of an underground shock wave absorber

    NASA Astrophysics Data System (ADS)

    Chikhradze, M.; Akhvlediani, I.; Bochorishvili, N.; Mataradze, E.

    2011-10-01

    The paper describes the mechanism and design of the wireless device for activation of energy absorber for localization of blast energy in underground openings. The statistics shows that the greatest share of accidents with fatal results associate with explosions in coal mines due to aero-methane and/or air-coal media explosion. The other significant problem is terrorist or accidental explosions in underground structures. At present there are different protective systems to reduce the blast energy. One of the main parts of protective Systems is blast Identification and Registration Module. The works conducted at G. Tsulukidze Mining Institute of Georgia enabled to construct the wireless system of explosion detection and mitigation of shock waves. The system is based on the constant control on overpressure. The experimental research continues to fulfill the system based on both threats, on the constant control on overpressure and flame parameters, especially in underground structures and coal mines. Reaching the threshold value of any of those parameters, the system immediately starts the activation. The absorber contains a pyrotechnic device ensuring the discharge of dispersed water. The operational parameters of wireless device and activation mechanisms of pyrotechnic element of shock wave absorber are discussed in the paper.

  17. Mitigation of Autoignition Due to Premixing in a Hypervelocity Flow Using Active Wall Cooling

    NASA Technical Reports Server (NTRS)

    Axdahl, Erik; Kumar, Ajay; Wilhite, Alan

    2013-01-01

    Preinjection of fuel on the forebody of an airbreathing vehicle is a proposed method to gain access to hypervelocity flight Mach numbers. However, this creates the possibility of autoignition either near the wall or in the core of the flow, thereby consuming fuel prematurely as well as increasing the amount of pressure drag on the vehicle. The computational fluid dynamics code VULCAN was used to conduct three dimensional simulations of the reacting flow in the vicinity of hydrogen injectors on a flat plate at conditions relevant to a Mach 12 notional flight vehicle forebody to determine the location where autoignition occurs. Active wall cooling strategies were formulated and simulated in response to regions of autoignition. It was found that tangential film cooling using hydrogen or helium were both able to nearly or completely eliminate wall autoignition in the flow domain of interest.

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

    SciTech Connect

    Bickford, W.E.

    1980-09-01

    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 /sup 56/Mn, /sup 54/Mn, /sup 57/Co, /sup 58/Co, /sup 60/Co, /sup 51/Cr, and /sup 99/Mo 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 10/sup 4/ Ci for a reference reactor design after only several days of operation, and approach 3.5 x 10/sup 4/ Ci in equilibrium. A mass transport model is then used to predict the deposition pattern of this inventory in the reactor cooling system.

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

    NASA Technical Reports Server (NTRS)

    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.

  20. Observations of the effect of wind on the cooling of active lava flows

    USGS Publications Warehouse

    Keszthelyi, L.; Harris, A.J.L.; Dehn, J.

    2003-01-01

    We present the first direct observations of the cooling of active lava flows by the wind. We confirm that atmospheric convective cooling processes (i.e., the wind) dominate heat loss over the lifetime of a typical pahochoe lava flow. In fact, the heat extracted by convection is greater than predicted, especially at wind speeds less than 5 m/s and surface temperatures less than 400??C. We currently estimate that the atmospheric heat transfer coefficient is about 45-50 W m-2 K-1 for a 10 m/s wind and a surface temperature ???500??C. Further field experiments and theoretical studies should expand these results to a broader range of surface temperatures and wind speeds.

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

    DOEpatents

    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.

  2. Light-induced self-assembly of active rectification devices.

    PubMed

    Stenhammar, Joakim; Wittkowski, Raphael; Marenduzzo, Davide; Cates, Michael E

    2016-04-01

    Self-propelled colloidal objects, such as motile bacteria or synthetic microswimmers, have microscopically irreversible individual dynamics-a feature they share with all living systems. The incoherent behavior of individual swimmers can be harnessed (or "rectified") by microfluidic devices that create systematic motions that are impossible in equilibrium. We present a computational proof-of-concept study showing that such active rectification devices could be created directly from an unstructured "primordial soup" of light-controlled motile particles, solely by using spatially modulated illumination to control their local propulsion speed. Alongside both microscopic irreversibility and speed modulation, our mechanism requires spatial symmetry breaking, such as a chevron light pattern, and strong interactions between particles, such as volume exclusion, which cause a collisional slowdown at high density. Together, we show how these four factors create a novel, many-body rectification mechanism. Our work suggests that standard spatial light modulator technology might allow the programmable, light-induced self-assembly of active rectification devices from an unstructured particle bath.

  3. A microfluidic paper-based device to assess acetylcholinesterase activity.

    PubMed

    Liu, Chunye; Gomez, Frank A

    2017-04-01

    Neurotransmitters play key roles in cell-to-cell communication. These chemical messengers are involved in many functional processes, including growth, reproduction, memory, and behavior. In this communication, we describe a novel microfluidic paper-based analytical device (μPAD) to detect acetylcholinesterase (AChE) activity and inhibitor screening through a colorimetric analysis. The μPAD is easily fabricated via a wax printing process whereby wax is deposited onto the surface of chromatographic paper, and heated to create a hydrophobic barrier. Separate solutions of 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) and samples containing AChE and acetylthiocholine iodide (ATC) (or cysteine, Cys), respectively, are directly spotted onto the μPAD. DTNB and AChE/ATC (or Cys) flow towards each other where a reaction occurs to form the yellow colored 2-nitro-5-thiobenzoic acid anion (TNB(2-) ). The device is dried, scanned, and analyzed yielding a linear range of average inverse yellow intensities versus substrate concentration. An IC50 value (0.045 nM) with a known inhibitor, neostigmine bromide (NB), is obtained on the device. μPADs are low cost and easy to fabricate and have great potential to quantify neurotransmitter activity.

  4. Light-induced self-assembly of active rectification devices

    PubMed Central

    Stenhammar, Joakim; Wittkowski, Raphael; Marenduzzo, Davide; Cates, Michael E.

    2016-01-01

    Self-propelled colloidal objects, such as motile bacteria or synthetic microswimmers, have microscopically irreversible individual dynamics—a feature they share with all living systems. The incoherent behavior of individual swimmers can be harnessed (or “rectified”) by microfluidic devices that create systematic motions that are impossible in equilibrium. We present a computational proof-of-concept study showing that such active rectification devices could be created directly from an unstructured “primordial soup” of light-controlled motile particles, solely by using spatially modulated illumination to control their local propulsion speed. Alongside both microscopic irreversibility and speed modulation, our mechanism requires spatial symmetry breaking, such as a chevron light pattern, and strong interactions between particles, such as volume exclusion, which cause a collisional slowdown at high density. Together, we show how these four factors create a novel, many-body rectification mechanism. Our work suggests that standard spatial light modulator technology might allow the programmable, light-induced self-assembly of active rectification devices from an unstructured particle bath. PMID:27051883

  5. Toxin activity assays, devices, methods and systems therefor

    DOEpatents

    Koh, Chung-Yan; Schaff, Ulrich Y.; Sommer, Gregory Jon

    2016-04-05

    Embodiments of the present invention are directed toward devices, system and method for conducting toxin activity assay using sedimentation. The toxin activity assay may include generating complexes which bind to a plurality of beads in a fluid sample. The complexes may include a target toxin and a labeling agent, or may be generated due to presence of active target toxin and/or labeling agent designed to be incorporated into complexes responsive to the presence of target active toxin. The plurality of beads including the complexes may be transported through a density media, wherein the density media has a lower density than a density of the beads and higher than a density of the fluid sample, and wherein the transporting occurs, at least in part, by sedimentation. Signal may be detected from the labeling agents of the complexes.

  6. Modeling Active Galactic Nucleus Feedback in Cool-core Clusters: The Formation of Cold Clumps

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Bryan, Greg L.

    2014-07-01

    We perform high-resolution (15-30 pc) adaptive mesh simulations to study the impact of momentum-driven active galactic nucleus (AGN) feedback in cool-core clusters, focusing in this paper on the formation of cold clumps. The feedback is jet-driven with an energy determined by the amount of cold gas within 500 pc of the super-massive black hole. When the intracluster medium in the core of the cluster becomes marginally stable to radiative cooling, with the thermal instability to the free-fall timescale ratio t TI/t ff < 3-10, cold clumps of gas start to form along the propagation direction of the AGN jets. By tracing the particles in the simulations, we find that these cold clumps originate from low entropy (but still hot) gas that is accelerated by the jet to outward radial velocities of a few hundred km s-1. This gas is out of hydrostatic equilibrium and so can cool. The clumps then grow larger as they decelerate and fall toward the center of the cluster, eventually being accreted onto the super-massive black hole. The general morphology, spatial distribution, and estimated Hα morphology of the clumps are in reasonable agreement with observations, although we do not fully replicate the filamentary morphology of the clumps seen in the observations, probably due to missing physics.

  7. Modeling active galactic nucleus feedback in cool-core clusters: The formation of cold clumps

    SciTech Connect

    Li, Yuan; Bryan, Greg L.

    2014-07-10

    We perform high-resolution (15-30 pc) adaptive mesh simulations to study the impact of momentum-driven active galactic nucleus (AGN) feedback in cool-core clusters, focusing in this paper on the formation of cold clumps. The feedback is jet-driven with an energy determined by the amount of cold gas within 500 pc of the super-massive black hole. When the intracluster medium in the core of the cluster becomes marginally stable to radiative cooling, with the thermal instability to the free-fall timescale ratio t{sub TI}/t{sub ff} < 3-10, cold clumps of gas start to form along the propagation direction of the AGN jets. By tracing the particles in the simulations, we find that these cold clumps originate from low entropy (but still hot) gas that is accelerated by the jet to outward radial velocities of a few hundred km s{sup –1}. This gas is out of hydrostatic equilibrium and so can cool. The clumps then grow larger as they decelerate and fall toward the center of the cluster, eventually being accreted onto the super-massive black hole. The general morphology, spatial distribution, and estimated Hα morphology of the clumps are in reasonable agreement with observations, although we do not fully replicate the filamentary morphology of the clumps seen in the observations, probably due to missing physics.

  8. Integration of active devices on smart polymers for neural interfaces

    NASA Astrophysics Data System (ADS)

    Avendano-Bolivar, Adrian Emmanuel

    The increasing ability to ever more precisely identify and measure neural interactions and other phenomena in the central and peripheral nervous systems is revolutionizing our understanding of the human body and brain. To facilitate further understanding, more sophisticated neural devices, perhaps using microelectronics processing, must be fabricated. Materials often used in these neural interfaces, while compatible with these fabrication processes, are not optimized for long-term use in the body and are often orders of magnitude stiffer than the tissue with which they interact. Using the smart polymer substrates described in this work, suitability for processing as well as chronic implantation is demonstrated. We explore how to integrate reliable circuitry onto these flexible, biocompatible substrates that can withstand the aggressive environment of the body. To increase the capabilities of these devices beyond individual channel sensing and stimulation, active electronics must also be included onto our systems. In order to add this functionality to these substrates and explore the limits of these devices, we developed a process to fabricate single organic thin film transistors with mobilities up to 0.4 cm2/Vs and threshold voltages close to 0V. A process for fabricating organic light emitting diodes on flexible substrates is also addressed. We have set a foundation and demonstrated initial feasibility for integrating multiple transistors onto thin-film flexible devices to create new applications, such as matrix addressable functionalized electrodes and organic light emitting diodes. A brief description on how to integrate waveguides for their use in optogenetics is addressed. We have built understanding about device constraints on mechanical, electrical and in vivo reliability and how various conditions affect the electronics' lifetime. We use a bi-layer gate dielectric using an inorganic material such as HfO 2 combined with organic Parylene-c. A study of

  9. Experimental investigations on active cooling thermal protection structure of hydrocarbon-fueled scramjet combustor in arc heated facility

    NASA Astrophysics Data System (ADS)

    Jianqiang, Tu; Jinlong, Peng; Xianning, Yang; Lianzhong, Chen

    2016-10-01

    The active cooling thermal protection technology is the efficient method to resolve the long-duration work and reusable problems of hydrocarbon-fueled scramjet combustor, where worst thermo-mechanical loads occur. The fuel is passed through coolant channels adjacent to the heated surfaces to absorb heat from the heating exchanger panels, prior to injection into the combustor. The heating exchanger both cooled down the wall temperature of the combustor wall and heats and cracks the hydrocarbon fuel inside the panel to permit an easier combustion and satisfying combustion efficiency. The subscale active cooling metallic panels, with dimensions of 100×100 mm and different coolant channel sizes, have been tested under typical combustion thermal environment produced by arc heated Turbulent Flow Duct (TFD). The heat exchange ability of different coolant channel sizes has been obtained. The big-scale active cooling metallic panel, with dimensions of 100 × 750 mm and the coolant channel sizes of better heating exchange performance, has been made and tested in the big-scale arc heated TFD facility. The test results show that the local superheated ablation is easy to happen for the cooling fuel assigned asymmetrically in the bigscale active cooling metallic panel, and the cooling fuel rate can reduce 8%˜10% after spraying the Thermal Barrier Coating (TBC) in the heating surface.

  10. EVIDENCE FOR WIDESPREAD COOLING IN AN ACTIVE REGION OBSERVED WITH THE SDO ATMOSPHERIC IMAGING ASSEMBLY

    SciTech Connect

    Viall, Nicholeen M.; Klimchuk, James A.

    2012-07-01

    A well-known behavior of EUV light curves of discrete coronal loops is that the peak intensities of cooler channels or spectral lines are reached at progressively later times than hotter channels. This time lag is understood to be the result of hot coronal loop plasma cooling through these lower respective temperatures. However, loops typically comprise only a minority of the total emission in active regions (ARs). Is this cooling pattern a common property of AR coronal plasma, or does it only occur in unique circumstances, locations, and times? The new Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) data provide a wonderful opportunity to answer this question systematically for an entire AR. We measure the time lag between pairs of SDO/AIA EUV channels using 24 hr of images of AR 11082 observed on 2010 June 19. We find that there is a time-lag signal consistent with cooling plasma, just as is usually found for loops, throughout the AR including the diffuse emission between loops for the entire 24 hr duration. The pattern persists consistently for all channel pairs and choice of window length within the 24 hr time period, giving us confidence that the plasma is cooling from temperatures of greater than 3 MK, and sometimes exceeding 7 MK, down to temperatures lower than {approx}0.8 MK. This suggests that the bulk of the emitting coronal plasma in this AR is not steady; rather, it is dynamic and constantly evolving. These measurements provide crucial constraints on any model which seeks to describe coronal heating.

  11. Large cooling differentials and high heat flux capability with p-type Bi2Te3/Sb2Te3 and n-type Bi2Te3/Bi2SexTe3-x Superlattice Thermoelectric Devices

    NASA Astrophysics Data System (ADS)

    Bulman, Gary; Siivola, Ed; Wiitala, Ryan; Grant, Brian; Pierce, Jonathan; Venkatasubramanian, Rama

    2007-03-01

    Thin film superlattice (SL) based thermoelectric (TE) devices offer the potential for improved efficiency and high heat flux cooling over conventional bulk materials. Recently, we have demonstrated external cooling of 55K and heat pumping capacity of 128 W/cm^2. These high heat fluxes in thin film devices, while attractive for cooling hot-spots in electronics, also make the device performance sensitive to various thermal resistances in the device structure. We will discuss advances in the cooling performance of Bi2Te3-based SL TE devices and describe a method to extract device material parameters, including thermal resistance, from measurements of their δT-I-V characteristics. These parameters will be compared to values obtained through Hall and Seebeck coefficient measurement on epitaxial materials. Results will be presented for both single couple and multi-couple modules, as well as multi-stage cascaded devices made with these materials. Single stage cooling couples with δTmax of 57.8K (Tc˜242K) and multi-stage modules with δTmax˜92.2K (Tc˜209K) have been measured. G.E. Bulman, E. Siivola, B. Shen and R. Venkatasubramanian, Appl. Phys. Lett. 89, 122117 (2006).

  12. The Use of Multiple Slate Devices to Support Active Reading Activities

    ERIC Educational Resources Information Center

    Chen, Nicholas Yen-Cherng

    2012-01-01

    Reading activities in the classroom and workplace occur predominantly on paper. Since existing electronic devices do not support these reading activities as well as paper, users have difficulty taking full advantage of the affordances of electronic documents. This dissertation makes three main contributions toward supporting active reading…

  13. A fuselage/tank structure study for actively cooled hypersonic cruise vehicles: Structural analysis

    NASA Technical Reports Server (NTRS)

    Baker, A. H.

    1975-01-01

    The effects of fuselage cross-section (circular and elliptical) and structural arrangement (integral and nonintegral tanks) on the performance of actively cooled hypersonic cruise vehicles was evaluated. It was found that integrally machined stiffening of the tank walls, while providing the most weight-efficient use of materials, results in higher production costs. Fatigue and fracture mechanics appeared to have little effect on the weight of the three study aircraft. The need for thermal strain relief through insulation is discussed. Aircraft size and magnitude of the internal pressure are seen to be significant factors in tank design.

  14. Performance of brazed graphite, carbon-fiber composite, and TZM materials for actively cooled structures; Qualification tests

    SciTech Connect

    Smid, I. ); Croessmann, C.D.; Watson, R.D. ); Linke, J. ); Cardella, A.; Bolt, H,. ); Reheis, N.; Kny, E. )

    1991-07-01

    The divertor of a near-term fusion device has to withstand high heat fluxes, heat shocks, and erosion caused by the plasma. Furthermore, it has to be maintainable through remote techniques. Above all, a good heat removal capability across the interface (low-Z armor/heat sink) plus overall integrity after many operational cycles are needed. To meet all these requirements, an active metal brazing technique is applied to bond graphite and carbon-fiber composite materials to a heat sink consisting of a Mo-41Re coolant tube through a TZM body. Plain brazed graphite and TZM tiles are tested for their fusion-relevant properties. The interfaces appear undamaged after thermal cycling when the melting point of the braze joint is not exceeded and when the graphite armor is {gt}4 mm thick. High heat flux tests are performed on three actively cooled divertor targets. The braze joints show no sign of failure after exposure to thermal loads {approximately}25% higher than the design value surface heat flux of 10 MW/m{sup 2}.

  15. Inquiry-based Science Activities Using The Infrared Zoo and Infrared Yellowstone Resources at Cool Cosmos

    NASA Astrophysics Data System (ADS)

    Daou, D.; Gauthier, A.

    2003-12-01

    Inquiry-based activities that utilize the Cool Cosmos image galleries have been designed and developed by K12 teachers enrolled in The Invisible Universe Online for Teachers course. The exploration activities integrate the Our Infrared World Gallery (http://coolcosmos.ipac.caltech.edu/image_galleries/our_ir_world_gallery.html) with either the Infrared Zoo gallery (http://coolcosmos.ipac.caltech.edu/image_galleries/ir_zoo/index.html) or the Infrared Yellowstone image http://coolcosmos.ipac.caltech.edu/image_galleries/ir_yellowstone/index.html) and video (http://coolcosmos.ipac.caltech.edu/videos/ir_yellowstone/index.html) galleries. Complete instructor guides have been developed for the activities and will be presented by the authors in poster and CD form. Although the activities are written for middle and highschool learners, they can easily be adapted for college audiences. The Our Infrared World Gallery exploration helps learners think critically about visible light and infrared light as they compare sets of images (IR and visible light) of known objects. For example: by taking a regular photograph of a running faucet, can you tell if it is running hot or cold water? What new information does the IR image give you? The Infrared Zoo activities encourage learners to investigate the differences between warm and cold blooded animals by comparing sets of IR and visible images. In one activity, learners take on the role of a pit viper seeking prey in various desert and woodland settings. The main activities are extended into the real world by discussing and researching industrial, medical, and societal applications of infrared technologies. The Infrared Yellowstone lessons give learners a unique perspective on Yellowstone National Park and it's spectacular geologic and geothermal features. Infrared video technology is highlighted as learners make detailed observations about the visible and infrared views of the natural phenomena. The "Cool Cosmos" EPO activities are

  16. Active fiber optic technologies used as tamper-indicating devices

    SciTech Connect

    Horton, P.R.V.; Waddoups, I.G.

    1995-11-01

    The Sandia National Laboratories (SNL) Safeguards and Seals Evaluation Program is evaluating new fiber optic active seal technologies for use at Department of Energy (DOE) facilities. The goal of the program is to investigate active seal technologies that can monitor secured containers storing special nuclear materials (SNM) within DOE vaults. Specifically investigated were active seal technologies that can be used as tamper-indicating devices to monitor secured containers within vaults while personnel remain outside the vault area. Such a system would allow minimal access into vaults while ensuring container content accountability. The purpose of this report is to discuss tamper-indicating devices that were evaluated for possible DOE use. While previous seal evaluations (Phase I and II) considered overall facility applications, this discussion focuses specifically on their use in vault storage situations. The report will highlight general background information, specifications and requirements, and test procedures. Also discussed are the systems available from four manufacturers: Interactive Technologies, Inc., Fiber SenSys, Inc., Inovonics, Inc., and Valve Security Systems.

  17. Active control of excessive sound emission on a mobile device.

    PubMed

    Jeon, Se-Woon; Youn, Dae Hee; Park, Young-cheol; Lee, Gun-Woo

    2015-04-01

    During a phone conversation, loud vocal emission from the far-end to the near-end space can disturb nearby people. In this paper, the possibility of actively controlling such unwanted sound emission using a control source placed on the mobile device is investigated. Two different approaches are tested: Global control, minimizing the potential energy measured along a volumetric space surface, and local control, minimizing the squared sound pressure at a discrete point on the phone. From the test results, both approaches can reduce the unwanted sound emission by more than 6 dB in the frequency range up to 2 kHz.

  18. Device for measuring oxygen activity in liquid sodium

    DOEpatents

    Roy, P.; Young, R.S.

    1973-12-01

    A composite ceramic electrolyte in a configuration (such as a closed end tube or a plate) suitable to separate liquid sodium from a reference electrode with a high impedance voltmeter connected to measure EMF between the sodium and the reference electrode as a measure of oxygen activity in the sodium is described. The composite electrolyte consists of zirconiacalcia with a bonded layer of thoria-yttria. The device is used with a gaseous reference electrode on the zirconia-calcia side and liquid sodium on the thoria-yttria side of the electrolyte. (Official Gazette)

  19. Infrared micro-thermography of an actively heated preconcentrator device

    NASA Astrophysics Data System (ADS)

    Furstenberg, Robert; Kendziora, C. A.; Stepnowski, Stanley V.; Mott, David R.; McGill, R. Andrew

    2008-03-01

    We report infrared micro-thermography measurements and analysis of static and transient temperature maps of an actively heated micro-fabricated preconcentrator device that incorporates a dual serpentine platinum heater trace deposited on a perforated polyimide membrane and suspended over a silicon frame. The sorbent coated perforated membrane is used to collect vapors and gases that flow through the preconcentrator. After heating, a concentrated pulse of analyte is released into the detector. Due to its small thermal mass, precise thermal management of the preconcentrator is critical to its performance. The sizes of features, the semi-transparent membrane, the need to flow air through the device, and changes in surface emissivity on a micron scale present many challenges for traditional infrared micro-thermography. We report an improved experimental test-bed. The hardware incorporates a custom-designed miniature calibration oven which, in conjunction with spatial filtering and a simple calibration algorithm, allows accurate temperature maps to be obtained. The test-bed incorporates a micro-bolometer array as the infrared imager. Instrumentation design, calibration and image processing algorithms are discussed and analyzed. The procedure does not require prior knowledge of the emissivity. We show that relatively inexpensive uncooled bolometers arrays can be used in certain radiometric applications. Heating profiles were examined with both uniform and non-uniform air flow through the device. The conclusions from this study provide critical information for optimal integration of the preconcentrator within a detection system, and in the design of the heater trace layout to achieve a more even temperature distribution across the device.

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

    SciTech Connect

    Linke, J.; Duwe, R.; Kuehnlein, W.

    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.

  1. Magnetocaloric Properties of Fe-Ni-Cr Nanoparticles for Active Cooling.

    PubMed

    Chaudhary, V; Ramanujan, R V

    2016-10-11

    Low cost, earth abundant, rare earth free magnetocaloric nanoparticles have attracted an enormous amount of attention for green, energy efficient, active near room temperature thermal management. Hence, we investigated the magnetocaloric properties of transition metal based (Fe70Ni30)100-xCrx (x = 1, 3, 5, 6 and 7) nanoparticles. The influence of Cr additions on the Curie temperature (TC) was studied. Only 5% of Cr can reduce the TC from ~438 K to 258 K. These alloys exhibit broad entropy v/s temperature curves, which is useful to enhance relative cooling power (RCP). For a field change of 5 T, the RCP for (Fe70Ni30)99Cr1 nanoparticles was found to be 548 J-kg(-1). Tunable TCin broad range, good RCP, low cost, high corrosion resistance and earth abundance make these nanoparticles suitable for low-grade waste heat recovery as well as near room temperature active cooling applications.

  2. Strong variable linear polarization in the cool active star II Peg

    NASA Astrophysics Data System (ADS)

    Rosén, Lisa; Kochukhov, Oleg; Wade, Gregg A.

    2014-08-01

    Magnetic fields of cool active stars are currently studied polarimetrically using only circular polarization observations. This provides limited information about the magnetic field geometry since circular polarization is only sensitive to the line-of-sight component of the magnetic field. Reconstructions of the magnetic field topology will therefore not be completely trustworthy when only circular polarization is used. On the other hand, linear polarization is sensitive to the transverse component of the magnetic field. By including linear polarization in the reconstruction the quality of the reconstructed magnetic map is dramatically improved. For that reason, we wanted to identify cool stars for which linear polarization could be detected at a level sufficient for magnetic imaging. Four active RS CVn binaries, II Peg, HR 1099, IM Peg, and σ Gem were observed with the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope. Mean polarization profiles in all four Stokes parameters were derived using the multi-line technique of least-squares deconvolution (LSD). Not only was linear polarization successfully detected in all four stars in at least one observation, but also, II Peg showed an extraordinarily strong linear polarization signature throughout all observations. This qualifies II Peg as the first promising target for magnetic Doppler imaging in all four Stokes parameters and, at the same time, suggests that other such targets can possibly be identified.

  3. Magnetocaloric Properties of Fe-Ni-Cr Nanoparticles for Active Cooling

    NASA Astrophysics Data System (ADS)

    Chaudhary, V.; Ramanujan, R. V.

    2016-10-01

    Low cost, earth abundant, rare earth free magnetocaloric nanoparticles have attracted an enormous amount of attention for green, energy efficient, active near room temperature thermal management. Hence, we investigated the magnetocaloric properties of transition metal based (Fe70Ni30)100‑xCrx (x = 1, 3, 5, 6 and 7) nanoparticles. The influence of Cr additions on the Curie temperature (TC) was studied. Only 5% of Cr can reduce the TC from ~438 K to 258 K. These alloys exhibit broad entropy v/s temperature curves, which is useful to enhance relative cooling power (RCP). For a field change of 5 T, the RCP for (Fe70Ni30)99Cr1 nanoparticles was found to be 548 J-kg‑1. Tunable TCin broad range, good RCP, low cost, high corrosion resistance and earth abundance make these nanoparticles suitable for low-grade waste heat recovery as well as near room temperature active cooling applications.

  4. Elemental abundances in atmospheres of cool dwarfs with solar-like activity

    NASA Astrophysics Data System (ADS)

    Antipova, L. I.; Boyarchuk, A. A.

    2016-01-01

    The elemental abundances in the atmosphere of the red dwarf HD 32147, which belongs to the HR 1614 moving groups, are analyzed. The atmospheric parameters determined from spectroscopic data (the condition of equal abundances for neutral and ionized atoms of a given element) differ considerably from those derived from photometry and parallax data. The abundances of several elements are also anomalous, with the anomaly increasing with decreasing ionization potential. It is concluded that this star is a red dwarf displaying solar-like activity; i.e., having dark (cool) spots on its surface, which may sometimes be considerable in size. Modeling synthetic spectra of stars with cool spots on their surfaces, with the spectral lines consisting of two components formed in media with different temperatures, indicate that the spectroscopic atmospheric parameters derived in such cases are incorrect; this can also explain the observed dependence of the elemental abundances on the corresponding ionization potentials. This leads to the conclusion thatHD32147 is indeed a star with solar-like activity. Several other such stars considered as examples display the same anomalies as those of HD 32147. These modeling results are also valid for Ap and Am stars, and are able to explain short-wavelength observations of the Sun and some stars (the FIP effect).

  5. Magnetocaloric Properties of Fe-Ni-Cr Nanoparticles for Active Cooling

    PubMed Central

    Chaudhary, V.; Ramanujan, R.V.

    2016-01-01

    Low cost, earth abundant, rare earth free magnetocaloric nanoparticles have attracted an enormous amount of attention for green, energy efficient, active near room temperature thermal management. Hence, we investigated the magnetocaloric properties of transition metal based (Fe70Ni30)100−xCrx (x = 1, 3, 5, 6 and 7) nanoparticles. The influence of Cr additions on the Curie temperature (TC) was studied. Only 5% of Cr can reduce the TC from ~438 K to 258 K. These alloys exhibit broad entropy v/s temperature curves, which is useful to enhance relative cooling power (RCP). For a field change of 5 T, the RCP for (Fe70Ni30)99Cr1 nanoparticles was found to be 548 J-kg−1. Tunable TCin broad range, good RCP, low cost, high corrosion resistance and earth abundance make these nanoparticles suitable for low-grade waste heat recovery as well as near room temperature active cooling applications. PMID:27725754

  6. Inferring Human Activity in Mobile Devices by Computing Multiple Contexts.

    PubMed

    Chen, Ruizhi; Chu, Tianxing; Liu, Keqiang; Liu, Jingbin; Chen, Yuwei

    2015-08-28

    This paper introduces a framework for inferring human activities in mobile devices by computing spatial contexts, temporal contexts, spatiotemporal contexts, and user contexts. A spatial context is a significant location that is defined as a geofence, which can be a node associated with a circle, or a polygon; a temporal context contains time-related information that can be e.g., a local time tag, a time difference between geographical locations, or a timespan; a spatiotemporal context is defined as a dwelling length at a particular spatial context; and a user context includes user-related information that can be the user's mobility contexts, environmental contexts, psychological contexts or social contexts. Using the measurements of the built-in sensors and radio signals in mobile devices, we can snapshot a contextual tuple for every second including aforementioned contexts. Giving a contextual tuple, the framework evaluates the posteriori probability of each candidate activity in real-time using a Naïve Bayes classifier. A large dataset containing 710,436 contextual tuples has been recorded for one week from an experiment carried out at Texas A&M University Corpus Christi with three participants. The test results demonstrate that the multi-context solution significantly outperforms the spatial-context-only solution. A classification accuracy of 61.7% is achieved for the spatial-context-only solution, while 88.8% is achieved for the multi-context solution.

  7. Inferring Human Activity in Mobile Devices by Computing Multiple Contexts

    PubMed Central

    Chen, Ruizhi; Chu, Tianxing; Liu, Keqiang; Liu, Jingbin; Chen, Yuwei

    2015-01-01

    This paper introduces a framework for inferring human activities in mobile devices by computing spatial contexts, temporal contexts, spatiotemporal contexts, and user contexts. A spatial context is a significant location that is defined as a geofence, which can be a node associated with a circle, or a polygon; a temporal context contains time-related information that can be e.g., a local time tag, a time difference between geographical locations, or a timespan; a spatiotemporal context is defined as a dwelling length at a particular spatial context; and a user context includes user-related information that can be the user’s mobility contexts, environmental contexts, psychological contexts or social contexts. Using the measurements of the built-in sensors and radio signals in mobile devices, we can snapshot a contextual tuple for every second including aforementioned contexts. Giving a contextual tuple, the framework evaluates the posteriori probability of each candidate activity in real-time using a Naïve Bayes classifier. A large dataset containing 710,436 contextual tuples has been recorded for one week from an experiment carried out at Texas A&M University Corpus Christi with three participants. The test results demonstrate that the multi-context solution significantly outperforms the spatial-context-only solution. A classification accuracy of 61.7% is achieved for the spatial-context-only solution, while 88.8% is achieved for the multi-context solution. PMID:26343665

  8. Materials Property Profiles for Actively Cooled Panels: An Illustration for Scramjet Applications

    NASA Astrophysics Data System (ADS)

    Vermaak, N.; Valdevit, L.; Evans, A. G.

    2009-04-01

    A scheme for identifying and visualizing the material properties that limit the performance of candidate materials for actively cooled aerospace propulsion components is presented and illustrated for combustor panels for Mach 7 hypersonic vehicles. The method provides a framework for exploring the nonlinear interactions between design and materials optimization. By probing the active constraints along the border of feasible design space, the limiting properties have been elucidated for a representative group of candidate materials. Property vectors that enhance design options have also been determined. For one of the promising candidate alloys (the Ni-based superalloy, INCONEL X-750), the possibilities of reclaiming design space and lowering optimal combustor panel weight by tailoring its strength properties are assessed.

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

    PubMed

    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.

  10. Design and fabrication of a radiative actively cooled honeycomb sandwich structural panel for a hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Ellis, D. A.; Pagel, L. L.; Schaeffer, D. M.

    1978-01-01

    The panel assembly consisted of an external thermal protection system (metallic heat shields and insulation blankets) and an aluminum honeycomb structure. The structure was cooled to temperature 442K (300 F) by circulating a 60/40 mass solution of ethylene glycol and water through dee shaped coolant tubes nested in the honeycomb and adhesively bonded to the outer skin. Rene'41 heat shields were designed to sustain 5000 cycles of a uniform pressure of + or - 6.89kPa (+ or - 1.0 psi) and aerodynamic heating conditions equivalent to 136 kW sq m (12 Btu sq ft sec) to a 422K (300 F) surface temperature. High temperature flexible insulation blankets were encased in stainless steel foil to protect them from moisture and other potential contaminates. The aluminum actively cooled honeycomb sandwich structural panel was designed to sustain 5000 cycles of cyclic in-plane loading of + or - 210 kN/m (+ or - 1200 lbf/in.) combined with a uniform panel pressure of + or - 6.89 kPa (?1.0 psi).

  11. Optimisation of concentrating solar cell systems with passive and active cooling

    NASA Astrophysics Data System (ADS)

    Blumenberg, J.

    1983-10-01

    Design considerations for concentrator solar cell arrays for space applications are reviewed, noting the restrictions on total mass that govern system selections. Consideration is given to systems with parabolic mirrors and Si and GaAs solar cells. Passive and active cooling systems for the arrays are discussed, as is the addition of a heat engine with a turbogenerator to utilize part of the waste heat of the cooling cycle. Attention is given to systems orbiting at 0.5, 1, and 3.5 AU from the sun. Flat panels are found to be more suitable for missions near the sun for Si solar cells, while GaAs cells with concentration are preferred to flat panel systems at all distances from the sun. Nuclear turboelectric systems are better than concentrator Si arrays at large distances from the sun, in terms of specific masses of the systems. The addition of a system to use waste heat is judged unfavorable from specific mass factors.

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

    NASA Astrophysics Data System (ADS)

    Mazzitelli, G.; Apicella, M. L.; Apruzzese, G.; Crescenzi, F.; Iannone, F.; Maddaluno, G.; Pericoli-Ridolfini, V.; Roccella, S.; Reale, M.; Viola, B.; Lyublinski, I.; Vertkov, A.

    2015-08-01

    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.

  13. Study of structural active cooling and heat sink systems for space shuttle

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This technology investigation was conducted to evaluate the feasibility of a number of thermal protection systems (TPS) concepts which are alternate candidates to the space shuttle baseline TPS. Four independent tasks were performed. Task 1 consisted of an in-depth evaluation of active structural cooling of the space shuttle orbiter. In Task 2, heat sink concepts for the booster were studied to identify and postulate solutions for design problems unique to heat sink TPS. Task 3 consisted of a feasibility demonstration test of a phase change material (PCM) incorporated into a reusable surface insulation (RSI) thermal protection system for the shuttle orbiter. In Task 4 the feasibility of heat pipes for stagnation region cooling was studied for the booster and the orbiter. Designs were developed for the orbiter leading edge and used in trade studies of leading edge concepts. At the time this program was initiated, a 2-stage fully reusable shuttle system was envisioned; therefore, the majority of the tasks were focused on the fully reusable system environments. Subsequently, a number of alternate shuttle system approaches, with potential for reduced shuttle system development funding requirements, were proposed. Where practicable, appropriate shifts in emphasis and task scoping were made to reflect these changes.

  14. PARduino: A Simple Device Measuring and Logging Photosynthetically Active Radiation

    NASA Astrophysics Data System (ADS)

    Barnard, H. R.; Findley, M. C.

    2013-12-01

    Photosynthetically Active Radiation (PAR, 400 to 700 nm) is one of the primary controls of forest carbon and water relations. In complex terrain, PAR has high spatial-variability. Given the high cost of commercial datalogging equipment, spatially-distributed measurements of PAR have been typically modeled using geographic coordinates and terrain indices. Here, we present a design for a low cost, field-deployable device for measuring and logging PAR built around an Arduino microcontroller (we named it PARduino). PARduino provides for widely distributed sensor arrays and tests the feasibility of using hobbyist-grade electronics for collecting scientific data. PARduino components include a LiCor quantum sensor, EME Systems signal converter/amplifier, and Sparkfun's Arduino Pro Mini microcontroller. Additional components include a real time clock, a microSD flash memory card, and a custom printed circuit board (PCB). We selected the components with an eye towards ease of assembly. Everything can be connected to the PCB using through-hole soldering techniques. Since the device will be deployed in remote research plots that lack easy access to line power, battery life was also a consideration in the design. Extended deployment is possible because PARduino's software keeps it in a low-power sleep mode until ready to make a measurement. PARduino will be open-source hardware for use and improvement by others.

  15. Cooled, temperature controlled electrometer

    DOEpatents

    Morgan, John P.

    1992-08-04

    A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.

  16. Cooled, temperature controlled electrometer

    DOEpatents

    Morgan, John P.

    1992-01-01

    A cooled, temperature controlled electrometer for the measurement of small currents. The device employs a thermal transfer system to remove heat from the electrometer circuit and its environment and dissipate it to the external environment by means of a heat sink. The operation of the thermal transfer system is governed by a temperature regulation circuit which activates the thermal transfer system when the temperature of the electrometer circuit and its environment exceeds a level previously inputted to the external variable temperature control circuit. The variable temperature control circuit functions as subpart of the temperature control circuit. To provide temperature stability and uniformity, the electrometer circuit is enclosed by an insulated housing.

  17. The Cost of Helium Refrigerators and Coolers for SuperconductingDevices as a Function of Cooling at 4 K

    SciTech Connect

    Green, Michael A.

    2007-08-27

    This paper is an update of papers written in 1991 and in1997 by Rod Byrns and this author concerning estimating the cost ofrefrigeration for superconducting magnets and cavities. The actual costsof helium refrigerators and coolers (escalated to 2007 dollars) areplotted and compared to a correlation function. A correlation functionbetween cost and refrigeration at 4.5 K is given. The capital cost oflarger refrigerators (greater than 10 W at 4.5 K) is plotted as afunction of 4.5-K cooling. The cost of small coolers is plotted as afunction of refrigeration available at 4.2 K. A correlation function forestimating efficiency (percent of Carnot) of both types of refrigeratorsis also given.

  18. Measurement of active shoulder proprioception: dedicated system and device.

    PubMed

    Lubiatowski, Przemyslaw; Ogrodowicz, Piotr; Wojtaszek, Marcin; Kaniewski, Ryszard; Stefaniak, Jakub; Dudziński, Witold; Romanowski, Leszek

    2013-02-01

    Proprioception is an essential part of shoulder stability and neuromuscular control. The purpose of the study was the development of a precise system of shoulder proprioception assessment in the active mode (Propriometr). For that purpose, devices such as the electronic goniometer and computer software had been designed. A pilot study was carried out on a control group of 27 healthy subjects, the average age being 23.8 (22-29) in order to test the system. The result of the assessment was the finding of the error of active reproduction of the joint position (EARJP). EARJP was assessed for flexion, abduction, external and internal rotation. For every motion, reference positions were used at three different angles. The results showed EARJP to range in 3-6.1°. The proprioception evaluation system (propriometr) allows a precise measurement of active joint position sense. The designed system can be used to assess proprioception in both shoulder injuries and treatment. In addition, all achieved results of normal shoulders may serve as reference to be compared with the results of forthcoming studies.

  19. Active cooling of pulse compression diffraction gratings for high energy, high average power ultrafast lasers.

    PubMed

    Alessi, David A; Rosso, Paul A; Nguyen, Hoang T; Aasen, Michael D; Britten, Jerald A; Haefner, Constantin

    2016-12-26

    Laser energy absorption and subsequent heat removal from diffraction gratings in chirped pulse compressors poses a significant challenge in high repetition rate, high peak power laser development. In order to understand the average power limitations, we have modeled the time-resolved thermo-mechanical properties of current and advanced diffraction gratings. We have also developed and demonstrated a technique of actively cooling Petawatt scale, gold compressor gratings to operate at 600W of average power - a 15x increase over the highest average power petawatt laser currently in operation. Combining this technique with low absorption multilayer dielectric gratings developed in our group would enable pulse compressors for petawatt peak power lasers operating at average powers well above 40kW.

  20. Fluxless Brazing and Heat Treatment of a Plate-Fin Sandwich Actively Cooled Panel

    NASA Technical Reports Server (NTRS)

    Beuyukian, C. S.

    1978-01-01

    The processes and techniques used to fabricate plate-fin sandwich actively cooled panels are presented. The materials were 6061 aluminum alloy and brazing sheet having clad brazing alloy. The panels consisted of small scale specimens, fatigue specimens, and a large 0.61 m by 1.22 m test panel. All panels were fluxless brazed in retorts in heated platen presses while exerting external pressure to assure intimate contact of details. Distortion and damage normally associated with that heat treatment were minimized by heat treating without fixtures and solution quenching in an organic polymer solution. The test panel is the largest fluxless brazed and heat treated panel of its configuration known to exist.

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

    NASA Astrophysics Data System (ADS)

    Asfandiyarov, Ruslan

    2013-12-01

    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

    NASA Astrophysics Data System (ADS)

    Guo, Fulai; Mathews, William G.

    2010-07-01

    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. Firefighter feedback during active cooling: a useful tool for heat stress management?

    PubMed

    Savage, Robbie J; Lord, Cara; Larsen, Brianna L; Knight, Teagan L; Langridge, Peter D; Aisbett, Brad

    2014-12-01

    Monitoring an individual's thermic state in the workplace requires reliable feedback of their core temperature. However, core temperature measurement technology is expensive, invasive and often impractical in operational environments, warranting investigation of surrogate measures which could be used to predict core temperature. This study examines an alternative measure of an individual's thermic state, thermal sensation, which presents a more manageable and practical solution for Australian firefighters operating on the fireground. Across three environmental conditions (cold, warm, hot & humid), 49 Australian volunteer firefighters performed a 20-min fire suppression activity, immediately followed by 20 min of active cooling using hand and forearm immersion techniques. Core temperature (Tc) and thermal sensation (TS) were measured across the rehabilitation period at five minute intervals. Despite the decline in Tc and TS throughout the rehabilitation period, there was little similarity in the magnitude or rate of decline between each measure in any of the ambient conditions. Moderate to strong correlations existed between Tc and TS in the cool (0.41, p<0.05) and hot & humid (0.57, p<0.05) conditions, however this was resultant in strong correlation during the earlier stages of rehabilitation (first five minutes), which were not evident in the latter stages. Linear regression revealed TS to be a poor predictor of Tc in all conditions (SEE=0.45-0.54°C) with a strong trend for TS to over-predict Tc (77-80% of the time). There is minimal evidence to suggest that ratings of thermal sensation, which represent a psychophysical assessment of an individual's thermal comfort, are an accurate reflection of the response of an individual's core temperature. Ratings of thermal sensation can be highly variable amongst individuals, likely moderated by local skin temperature. In account of these findings, fire managers require a more reliable source of information to guide

  4. Study of a fail-safe abort system for an actively cooled hypersonic aircraft. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Pirello, C. J.; Herring, R. L.

    1976-01-01

    Conceptual designs of a fail-safe abort system for hydrogen fueled actively cooled high speed aircraft are examined. The fail-safe concept depends on basically three factors: (1) a reliable method of detecting a failure or malfunction in the active cooling system, (2) the optimization of abort trajectories which minimize the descent heat load to the aircraft, and (3) fail-safe thermostructural concepts to minimize both the weight and the maximum temperature the structure will reach during descent. These factors are examined and promising approaches are evaluated based on weight, reliability, ease of manufacture and cost.

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

    NASA Astrophysics Data System (ADS)

    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

  6. Thermal Manikin Evaluation of Passive and Active Cooling Garments to Improve Comfort of Military Body Armor

    DTIC Science & Technology

    2007-08-01

    increased TM evaporative cooling potential approximately 18%. Military use of these garments could allow for increases in sweat evaporation and overall thermal comfort during operational heat exposure.

  7. Cooling Vest

    NASA Technical Reports Server (NTRS)

    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.

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

    ERIC Educational Resources Information Center

    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…

  9. Desensitization of menthol-activated cold receptors in lower extremities during local cooling in young women with a cold constitution.

    PubMed

    Yamazaki, Fumio; Sone, Ryoko

    2017-03-01

    To test the hypothesis that topical menthol-induced reactivity of cold sensation and cutaneous vasoconstriction to local cooling is augmented in individuals with a cold constitution, we examined thermal sensation and cutaneous vasoconstrictor responses at menthol-treated and untreated sites in the legs during local skin cooling in young women complaining of chilliness (C group) and young women with no complaint as a normal control group (N group). During local skin cooling, the sensitivity to cold sensation was greater in the C group than in the N group. The application of menthol enhanced the cold sensation at a low temperature in the N group, but not in the C group. Cutaneous vasoconstrictor responses to local skin cooling were not altered by menthol treatment in either of the two groups. These findings suggest the desensitization of menthol-activated cold receptors in the legs of C group subjects, and a minor role of cold receptor activity in cutaneous vasoconstrictor response to local cooling.

  10. A status of the activities of the NASA. Marshall Space Flight Center Combustion Devices Technology Team

    NASA Technical Reports Server (NTRS)

    Tucker, Kevin

    1992-01-01

    The Consortium for Computational Fluid Dynamics (CFD) Applications in Propulsion Technology was established to focus on computational fluid dynamics applications in propulsion. Specific areas of effort include developing the CFD technology required to address rocket propulsion issues, validating the technology, and applying the validated technology to design problems. The Combustion Devices Technology Team was formed to implement the above objectives in the broad area of combustion driven flows. In an effort to bring CFD to bear in the design environment, the team has focused its efforts on the Space Transportation Main Engine nozzle. The main emphasis has been on the film cooling scheme used to cool the nozzle wall. Benchmark problems have been chosen to validate CFD film cooling capabilities. CFD simulations of the subscale nozzle have been made. Also, CFD predictions of the base flow resulting from this type of nozzle have been made. The status of these calculations is presented along with future plans. Information is given in viewgraph form.

  11. Intelligent Engine Systems: Thermal Management and Advanced Cooling

    NASA Technical Reports Server (NTRS)

    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.

  12. Nanoporous noninvasive cellular electrical activity-based analysis devices.

    PubMed

    Prasad, Shalini; Quijano, Jorge

    2007-03-01

    In recent years, rapid advancements have been made in the biomedical applications of microtechnology and nanotechnology. While the focus of such technologies have been primarily on in vitro analytical and diagnostic tools, more recently in vivo therapeutic and sensing applications have gained attention. The long-term integration of cells with inorganic materials provides the basis for novel sensing platforms. The work presented here focuses on the ability to maintain cells long-term in nanoporous silicon-based microenvironments. This article describes the creation of nanoporous, biocompatible, alumina membranes as a platform for incorporation into a cell-based device targeted for in situ recording of cellular electrical activity variations due to the changes associated with the surrounding microenvironments. Studies described herein focus on the interaction of nanoporous alumina substrates embedded in silicon patterned with cells of interest. The fidelity of such a system is demonstrated in terms of viability, proliferation, and functionality. The capability of such microfabricated nanoporous membranes, as in vitro for cell-based assays for sensing and drug delivery applications, is also demonstrated. It has potential in vivo application for therapeutic immunoisolation.

  13. Active pixel as dosimetric device for interventional radiology

    NASA Astrophysics Data System (ADS)

    Servoli, L.; Baldaccini, F.; Biasini, M.; Checcucci, B.; Chiocchini, S.; Cicioni, R.; Conti, E.; Di Lorenzo, R.; Dipilato, A. C.; Esposito, A.; Fanó, L.; Paolucci, M.; Passeri, D.; Pentiricci, A.; Placidi, P.

    2013-08-01

    Interventional Radiology (IR) is a subspecialty of radiology comprehensive of all minimally invasive diagnostic and therapeutic procedures performed using radiological devices to obtain image guidance. The interventional procedures are potentially harmful for interventional radiologists and medical staff due to the X-ray diffusion by the patient's body. The characteristic energy range of the diffused photons spans few tens of keV. In this work we will present a proposal for a new X-ray sensing element in the energy range of interest for IR procedures. The sensing element will then be assembled in a dosimeter prototype, capable of real-time measurement, packaged in a small form-factor, with wireless communication and no external power supply to be used for individual operators dosimetry for IR procedures. For the sensor, which is the heart of the system, we considered three different Active Pixel Sensors (APS). They have shown a good capability as single X-ray photon detectors, up to several tens keV photon energy. Two dosimetric quantities have been considered, the number of detected photons and the measured energy deposition. Both observables have a linear dependence with the dose, as measured by commercial dosimeters. The uncertainties in the measurement are dominated by statistic and can be pushed at ˜5% for all the sensors under test.

  14. Development of a laboratory demonstration model active cleaning device

    NASA Technical Reports Server (NTRS)

    Shannon, R. L.; Gillette, R. B.

    1975-01-01

    A laboratory demonstration model of a device for removing contaminant films from optical surfaces in space was developed. The development of a plasma tube, which would produce the desired cleaning effects under high vacuum conditions, represented the major problem in the program. This plasma tube development is discussed, and the resulting laboratory demonstration-model device is described.

  15. Diagnostic for two-mode variable valve activation device

    SciTech Connect

    Fedewa, Andrew M

    2014-01-07

    A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

  16. Superconductor rotor cooling system

    DOEpatents

    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.

  17. Superconductor rotor cooling system

    DOEpatents

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

    2002-01-01

    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.

  18. Electronic security systems and active implantable medical devices.

    PubMed

    Irnich, Werner

    2002-08-01

    How do active implantable medical devices react in the presence of strong magnetic fields in the frequency range between extremely low frequency (ELF) to radiofrequency (RF) as they are emitted by electronic security systems (ESS)? There are three different sorts of ESSs: electronic article surveillance (EAS) devices, metal detector (MDS) devices, and radiofrequency identification (RFID) systems. Common to all is the production of magnetic fields. There is an abundance of literature concerning interference by ESS gates with respect to if there is an influence possible and if such an influence can bear a risk for the AIMD wearers. However, there has been no attempt to study the physical mechanism nor to develop a model of how and under which conditions magnetic fields can influence pacemakers and defibrillators and how they could be disarmed by technological means. It is too often assumed that interference of AIMD with ESS is inevitable. Exogenous signals of similar intensity and rhythm to heart signals can be misinterpreted and, thus, confuse the implant. Important for the interference coupling mechanism is the differentiation between a "unipolar" and a "bipolar" system. With respect to magnetic fields, the left side implanted pacemaker is the most unfavorable case as the lead forms approximately a semicircular area of maximum 225 cm2 into which a voltage can be induced. This assumption yields an interference coupling model that can be expressed by simple mathematics. The worst-case conditions for induced interference voltages are a coupling area of 225 cm2 that is representative for a large human, a homogeneous magnetic field perpendicular to the area formed by the lead, and a unipolar ventricular pacemaker system that is implanted on the left side of the thorax and has the highest interference sensitivity. In bipolar systems the fields must be 17 times larger when compared to a unipolar system to have the same effect. The magnetic field for interfering with ICDs

  19. A relationship between halo mass, cooling, active galactic nuclei heating and the co-evolution of massive black holes

    NASA Astrophysics Data System (ADS)

    Main, R. A.; McNamara, B. R.; Nulsen, P. E. J.; Russell, H. R.; Vantyghem, A. N.

    2017-02-01

    We derive X-ray mass, luminosity, and temperature profiles for 45 galaxy clusters to explore relationships between halo mass, active galactic nuclei (AGN) feedback, and central cooling time. We find that radio-mechanical feedback power (referred to here as `AGN power') in central cluster galaxies correlates with halo mass as Pmech ∝ M1.55 ± 0.26, but only in haloes with central atmospheric cooling times shorter than 1 Gyr. The trend of AGN power with halo mass is consistent with the scaling expected from a self-regulating AGN feedback loop, as well as with galaxy and central black hole co-evolution along the MBH-σ relation. AGN power in clusters with central atmospheric cooling times longer than ˜1 Gyr typically lies two orders of magnitude below those with shorter central cooling times. Galaxies centred in clusters with long central cooling times nevertheless experience ongoing and occasionally powerful AGN outbursts. We further investigate the impact of feedback on cluster scaling relations. We find L-T and M-T relations in clusters with direct evidence of feedback which are steeper than self-similar, but not atypical compared to previous studies of the full cluster population. While the gas mass rises, the stellar mass remains nearly constant with rising total mass, consistent with earlier studies. This trend is found regardless of central cooling time, implying tight regulation of star formation in central galaxies as their haloes grew, and long-term balance between AGN heating and atmospheric cooling. Our scaling relations are presented in forms that can be incorporated easily into galaxy evolution models.

  20. Design and fabrication of a stringer stiffened discrete-tube actively cooled panel for a hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Anthony, F. M.; Halenbrook, R. G.

    1981-01-01

    A 0.61 x 1.22 m (2 x 4 ft) test panel was fabricated and delivered to the Langley Research Center for assessment of the thermal and structural features of the optimized panel design. The panel concept incorporated an aluminum alloy surface panel actively cooled by a network of discrete, parallel, redundant, counterflow passage interconnected with appropriate manifolding, and assembled by adhesive bonding. The cooled skin was stiffened with a mechanically fastened conventional substructure of stringers and frames. A 40 water/60 glycol solution was the coolant. Low pressure leak testing, radiography, holography and infrared scanning were applied at various stages of fabrication to assess integrity and uniformity. By nondestructively inspecting selected specimens which were subsequently tested to destruction, it was possible to refine inspection standards as applied to this cooled panel design.

  1. Suppressing cluster cooling flows by self-regulated heating from a spatially distributed population of active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Nusser, Adi; Silk, Joseph; Babul, Arif

    2006-12-01

    Existing models invoking active galactic nucleus (AGN) activity to resolve the cooling flow conundrum in galaxy clusters focus exclusively on the role of the central galaxy. Such models require fine-tuning of highly uncertain microscopic transport properties to distribute the thermal over the entire cluster cooling core. We propose that the intracluster medium (ICM) is instead heated by multiple, spatially distributed AGN. The central regions of galaxy clusters are rich in spheroidal systems, all of which are thought to host black holes and could participate in the heating of the ICM via AGN activity of varying strengths, and they do. There is mounting observational evidence for multiple AGN in cluster environments. AGN drive bubbles into the ICM. We identify three distinct interactions between the bubble and the ICM: (1) upon injection, the bubbles expand rapidly in situ to reach pressure equilibrium with their surroundings, generating shocks and waves whose dissipation is the principal source of ICM heating; (2) once inflated, the bubbles rise buoyantly at a rate determined by a balance with the viscous drag force, which itself results in some additional heating; and (3) rising bubbles expand and compress their surroundings. This process is adiabatic and does not contribute to any additional heating; rather, the increased ICM density due to compression enhances cooling. Our model sidesteps the `transport' issue by relying on the spatially distributed galaxies to heat the cluster core. We include self-regulation in our model by linking AGN activity in a galaxy to cooling characteristics of the surrounding ICM. We use a spherically symmetric one-dimensional hydrodynamical code to carry out a preliminary study illustrating the efficacy of the model. Our self-regulating scenario predicts that there should be enhanced AGN activity of galaxies inside the cooling regions compared to galaxies in the outer parts of the cluster. This prediction remains to be confirmed or

  2. Highly porous activated carbon based adsorption cooling system employing difluoromethane and a mixture of pentafluoroethane and difluoromethane

    NASA Astrophysics Data System (ADS)

    Askalany, Ahmed A.; Saha, Bidyut B.

    2017-01-01

    This paper presents a simulation for a low-grade thermally powered two-beds adsorption cooling system employing HFC-32 and a mixture of HFC-32 and HFC-125 (HFC-410a) with activated carbon of type Maxsorb III. The present simulation model adopts experimentally measured adsorption isotherms, adsorption kinetics and isosteric heat of adsorption data. Effect of operating conditions (mass flow rate of hot water, driving heat source temperature and evaporator temperature) on the system performance has been studied in detail. The simulation results showed that the system could be powered by low-grade heat source temperature (below 85 °C). AC/HFC-32 and AC/HFC-410a adsorption cooling cycles achieved close specific cooling power and coefficient of performance values of 0.15 kW/kg and 0.3, respectively at a regeneration temperature of 90 °C along with evaporator temperature of 10 °C. The investigated semi continuous adsorption cooling system could produce a cooling power of 9 kW.

  3. Electroforming of Bi(1-x)Sb(x) nanowires for high-efficiency micro-thermoelectric cooling devices on a chip.

    SciTech Connect

    Overmyer, Donald L.; Webb, Edmund Blackburn, III; Siegal, Michael P.; Yelton, William Graham

    2006-11-01

    Active cooling of electronic systems for space-based and terrestrial National Security missions has demanded use of Stirling, reverse-Brayton, closed Joule-Thompson, pulse tube and more elaborate refrigeration cycles. Such cryocoolers are large systems that are expensive, demand large powers, often contain moving parts and are difficult to integrate with electronic systems. On-chip, solid-state, active cooling would greatly enhance the capabilities of future systems by reducing the size, cost and inefficiencies compared to existing solutions. We proposed to develop the technology for a thermoelectric cooler capable of reaching 77K by replacing bulk thermoelectric materials with arrays of Bi{sub 1-x}Sb{sub x} nanowires. Furthermore, the Sandia-developed technique we will use to produce the oriented nanowires occurs at room temperature and can be applied directly to a silicon substrate. Key obstacles include (1) optimizing the Bi{sub 1-x}Sb{sub x} alloy composition for thermoelectric properties; (2) increasing wire aspect ratios to 3000:1; and (3) increasing the array density to {ge} 10{sup 9} wires/cm{sup 2}. The primary objective of this LDRD was to fabricate and test the thermoelectric properties of arrays of Bi{sub 1-x}Sb{sub x} nanowires. With this proof-of-concept data under our belts we are positioned to engage National Security systems customers to invest in the integration of on-chip thermoelectric coolers for future missions.

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

    SciTech Connect

    Uckan, T.; Mioduszewski, P.K.; Loarer, T.; Chatelier, M.; Guilhem, D.; Lutz, T.; Nygren, R.E.; Mahdavi, M.A.

    1995-08-01

    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 m{sup 3}/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 {approximately}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.

  5. EFFECT OF ACTIVE COOLING AND α-2 ADRENOCEPTOR ANTAGONISM ON CORE TEMPERATURE IN ANESTHETIZED BROWN BEARS (URSUS ARCTOS).

    PubMed

    Ozeki, Larissa Mourad; Caulkett, Nigel; Stenhouse, Gordon; Arnemo, Jon M; Fahlman, Åsa

    2015-06-01

    Hyperthermia is a common complication during anesthesia of bears, and it can be life threatening. The objective of this study was to evaluate the effectiveness of active cooling on core body temperature for treatment of hyperthermia in anesthetized brown bears (Ursus arctos). In addition, body temperature after reversal with atipamezole was also evaluated. Twenty-five adult and subadult brown bears were captured with a combination of zolazepam-tiletamine and xylazine or medetomidine. A core temperature capsule was inserted into the bears' stomach or 15 cm into their rectum or a combination of both. In six bears with gastric temperatures≥40.0°C, an active cooling protocol was performed, and the temperature change over 30 min was analyzed. The cooling protocol consisted of enemas with 2 L of water at approximately 5°C/100 kg of body weight every 10 min, 1 L of intravenous fluids at ambient temperature, water or snow on the paws or the inguinal area, intranasal oxygen supplementation, and removing the bear from direct sunlight or providing shade. Nine bears with body temperature>39.0°C that were not cooled served as control for the treated animals. Their body temperatures were recorded for 30 min, prior to administration of reversal. At the end of the anesthetic procedure, all bears received an intramuscular dose of atipamezole. In 10 bears, deep rectal temperature change over 30 min after administration of atipamezole was evaluated. The active cooling protocol used in hyperthermic bears significantly decreased their body temperatures within 10 min, and it produced a significantly greater decrease in their temperature than that recorded in the control group.

  6. Measurement of marine picoplankton cell size by using a cooled, charge-coupled device camera with image-analyzed fluorescence microscopy

    SciTech Connect

    Viles, C.L.; Sieracki, M.E. )

    1992-02-01

    Accurate measurement of the biomass and size distribution of picoplankton cells (0.2 to 2.0 {mu}m) is paramount in characterizing their contribution to the oceanic food web and global biogeochemical cycling. Image-analyzed fluorescence microscopy, usually based on video camera technology, allows detailed measurements of individual cells to be taken. The application of an imaging system employing a cooled, slow-scan charge-coupled device (CCD) camera to automated counting and sizing of individual picoplankton cells from natural marine samples is described. A slow-scan CCD-based camera was compared to a video camera and was superior for detecting and sizing very small, dim particles such as fluorochrome-stained bacteria. Several edge detection methods for accurately measuring picoplankton cells were evaluated. Standard fluorescent microspheres and a Sargasso Sea surface water picoplankton population were used in the evaluation. Global thresholding was inappropriate for these samples. Methods used previously in image analysis of nanoplankton cells (2 to 20 {mu}m) also did not work well with the smaller picoplankton cells. A method combining an edge detector and an adaptive edge strength operator worked best for rapidly generating accurate cell sizes. A complete sample analysis of more than 1,000 cells averages about 50 min and yields size, shape, and fluorescence data for each cell. With this system, the entire size range of picoplankton can be counted and measured.

  7. Noiseless Non-Reciprocity in a Parametric Active Device

    DTIC Science & Technology

    2011-04-01

    and isolators belong to an important class of microwave components employed in applications including the measurement of mesoscopic circuits at...devices such as circulators and isolators belong to an important class of microwave components employed in applications including the measurement of...class of microwave components employed in applications including the measurement of mesoscopic circuits at cryogenic temperatures. The measurement

  8. Symmetric miniaturized heating system for active microelectronic devices

    NASA Astrophysics Data System (ADS)

    McCracken, Michael; Mayer, Michael; Jourard, Isaac; Moon, Jeong-Tak; Persic, John

    2010-07-01

    To qualify interconnect technologies such as microelectronic fine wire bonds for mass production of integrated circuit (IC) packages, it is necessary to perform accelerated aging tests, e.g., to age a device at an elevated temperature or to subject the device to thermal cycling and measure the decrease of interconnect quality. There are downsides to using conventional ovens for this as they are relatively large and have relatively slow temperature change rates, and if electrical connections are required between monitoring equipment and the device being heated, they must be located inside the oven and may be aged by the high temperatures. Addressing these downsides, a miniaturized heating system (minioven) is presented, which can heat individual IC packages containing the interconnects to be tested. The core of this system is a piece of copper cut from a square shaped tube with high resistance heating wire looped around it. Ceramic dual in-line packages are clamped against either open end of the core. One package contains a Pt100 temperature sensor and the other package contains the device to be aged placed in symmetry to the temperature sensor. According to the temperature detected by the Pt100, a proportional-integral-derivative controller adjusts the power supplied to the heating wire. The system maintains a dynamic temperature balance with the core hot and the two symmetric sides with electrical connections to the device under test at a cooler temperature. Only the face of the package containing the device is heated, while the socket holding it remains below 75 °C when the oven operates at 200 °C. The minioven can heat packages from room temperature up to 200 °C in less than 5 min and maintain this temperature at 28 W power. During long term aging, a temperature of 200 °C was maintained for 1120 h with negligible resistance change of the heating wires after 900 h (heating wire resistance increased 0.2% over the final 220 h). The device is also subjected to

  9. Symmetric miniaturized heating system for active microelectronic devices.

    PubMed

    McCracken, Michael; Mayer, Michael; Jourard, Isaac; Moon, Jeong-Tak; Persic, John

    2010-07-01

    To qualify interconnect technologies such as microelectronic fine wire bonds for mass production of integrated circuit (IC) packages, it is necessary to perform accelerated aging tests, e.g., to age a device at an elevated temperature or to subject the device to thermal cycling and measure the decrease of interconnect quality. There are downsides to using conventional ovens for this as they are relatively large and have relatively slow temperature change rates, and if electrical connections are required between monitoring equipment and the device being heated, they must be located inside the oven and may be aged by the high temperatures. Addressing these downsides, a miniaturized heating system (minioven) is presented, which can heat individual IC packages containing the interconnects to be tested. The core of this system is a piece of copper cut from a square shaped tube with high resistance heating wire looped around it. Ceramic dual in-line packages are clamped against either open end of the core. One package contains a Pt100 temperature sensor and the other package contains the device to be aged placed in symmetry to the temperature sensor. According to the temperature detected by the Pt100, a proportional-integral-derivative controller adjusts the power supplied to the heating wire. The system maintains a dynamic temperature balance with the core hot and the two symmetric sides with electrical connections to the device under test at a cooler temperature. Only the face of the package containing the device is heated, while the socket holding it remains below 75 degrees C when the oven operates at 200 degrees C. The minioven can heat packages from room temperature up to 200 degrees C in less than 5 min and maintain this temperature at 28 W power. During long term aging, a temperature of 200 degrees C was maintained for 1120 h with negligible resistance change of the heating wires after 900 h (heating wire resistance increased 0.2% over the final 220 h). The

  10. Combustion devices technology team - An overview and status of STME-related activities

    NASA Technical Reports Server (NTRS)

    Tucker, P. K.; Croteau-Gillespie, Margie

    1992-01-01

    The Consortium for CFD applications in propulsion technology has been formed at NASA/Marshall Space Flight Center. The combustion devices technology team is one of the three teams that constitute the Consortium. While generally aiming to advance combustion devices technology for rocket propulsion, the team's efforts for the last 1 and 1/2 years have been focused on issues relating to the Space Transportation Main Engine (STME) nozzle. The nozzle design uses hydrogen-rich turbine exhaust to cool the wall in a film/dump scheme. This method of cooling presents challenges and associated risks for the nozzle designers and the engine/vehicle integrators. Within the nozzle itself, a key concern is the ability to effectively and efficiently film cool the wall. From the National Launch System vehicle base standpoint, there are concerns with dumping combustible gases at the nozzle exit and their potential adverse effects on the base thermal environment. The Combustion Team has developed and is implementing plans to use validated CFD tools to aid in risk mitigation for both areas.

  11. Spectroscopic study of a dark lane and a cool loop in a solar limb active region by Hinode/EIS

    SciTech Connect

    Lee, Kyoung-Sun; Imada, S.; Moon, Y.-J.; Lee, Jin-Yi

    2014-01-10

    We investigated a cool loop and a dark lane over a limb active region on 2007 March 14 using the Hinode/EUV Imaging Spectrometer. The cool loop is clearly seen in the spectral lines formed at the transition region temperature. The dark lane is characterized by an elongated faint structure in the coronal spectral lines and is rooted on a bright point. We examined their electron densities, Doppler velocities, and nonthermal velocities as a function of distance from the limb. We derived electron densities using the density sensitive line pairs of Mg VII, Si X, Fe XII, Fe XIII, and Fe XIV spectra. We also compared the observed density scale heights with the calculated scale heights from each peak formation temperatures of the spectral lines under the hydrostatic equilibrium. We noted that the observed density scale heights of the cool loop are consistent with the calculated heights, with the exception of one observed cooler temperature; we also found that the observed scale heights of the dark lane are much lower than their calculated scale heights. The nonthermal velocity in the cool loop slightly decreases along the loop, while nonthermal velocity in the dark lane sharply falls off with height. Such a decrease in the nonthermal velocity may be explained by wave damping near the solar surface or by turbulence due to magnetic reconnection near the bright point.

  12. Cool Sportswear

    NASA Technical Reports Server (NTRS)

    1982-01-01

    New athletic wear design based on the circulating liquid cooling system used in the astronaut's space suits, allows athletes to perform more strenuous activity without becoming overheated. Techni-Clothes gear incorporates packets containing a heat-absorbing gel that slips into an insulated pocket of the athletic garment and is positioned near parts of the body where heat transfer is most efficient. A gel packet is good for about one hour. Easily replaced from a supply of spares in an insulated container worn on the belt. The products, targeted primarily for runners and joggers and any other athlete whose performance may be affected by hot weather, include cooling headbands, wrist bands and running shorts with gel-pack pockets.

  13. Cooling of nanomechanical resonators by thermally activated single-electron transport.

    PubMed

    Santandrea, F; Gorelik, L Y; Shekhter, R I; Jonson, M

    2011-05-06

    We show that the vibrations of a nanomechanical resonator can be cooled to near its quantum ground state by tunneling injection of electrons from a scanning tunneling microscope tip. The interplay between two mechanisms for coupling the electronic and mechanical degrees of freedom results in a bias-voltage-dependent difference between the probability amplitudes for vibron emission and absorption during tunneling. For a bias voltage just below the Coulomb blockade threshold, we find that absorption dominates, which leads to cooling corresponding to an average vibron population of the fundamental bending mode of 0.2.

  14. Integrated Electromechanical Devices for Active Control of Vibration and Sound

    DTIC Science & Technology

    1997-11-01

    of peak power • Minimize ambient noise generation broadband and narrowband • Standard temperature (-25C--55C) with possible extended operation • Must...operate in a vacuum and in non-volatile fluids • Minimize heat generation , EMI, and outgassing • Baseline for application to flat surfaces but allow... generation . An actuator integrated in an electromechanical device could generate sufficient internal heat to affect other components, or alter its

  15. Impact of optical antennas on active optoelectronic devices.

    PubMed

    Bonakdar, Alireza; Mohseni, Hooman

    2014-10-07

    Remarkable progress has been made in the fabrication and characterization of optical antennas that are integrated with optoelectronic devices. Herein, we describe the fundamental reasons for and experimental evidence of the dramatic improvements that can be achieved by enhancing the light-matter interaction via an optical antenna in both photon-emitting and -detecting devices. In addition, integration of optical antennas with optoelectronic devices can lead to the realization of highly compact multifunctional platforms for future integrated photonics, such as low-cost lab-on-chip systems. In this review paper, we further focus on the effect of optical antennas on the detectivity of infrared photodetectors. One particular finding is that the antenna can have a dual effect on the specific detectivity, while it can elevate light absorption efficiency of sub-wavelength detectors, it can potentially increase the noise of the detectors due to the enhanced spontaneous emission rate. In particular, we predict that the detectivity of interband photon detectors can be negatively affected by the presence of optical antennas across a wide wavelength region covering visible to long wavelength infrared bands. In contrast, the detectivity of intersubband detectors could be generally improved with a properly designed optical antenna.

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

    PubMed

    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

  17. Measuring steps with the Fitbit activity tracker: an inter-device reliability study.

    PubMed

    Dontje, Manon L; de Groot, Martijn; Lengton, Remko R; van der Schans, Cees P; Krijnen, Wim P

    2015-01-01

    Activity trackers like Fitbit are used for self-tracking of physical activity by an increasing number of individuals. Comparing physical activity scores with peers can contribute to the desired behavioural change. However, for meaningful social comparison a high inter-device reliability is paramount. This study aimed to determine the inter-device reliability of Fitbit activity trackers in measuring steps. Ten activity trackers (Fitbit Ultra) were worn by a single person (male, 46 years) during eight consecutive days. Inter-device reliability was assessed on three different levels of aggregation (minutes, hours, days) with various methods, including intra-class correlation coefficient (ICC), Bland-Altman plots, limits of agreement (LOA) and Mixed Model Analysis. Results showed that the inter-device reliability of the Fitbit in measuring steps is good at all levels of aggregation (minutes, hours, days), but especially when steps were measured per day. This implies that individuals can reliably compare their daily physical activity scores with peers.

  18. Rho kinase activation and ROS production contributes to the cooling enhanced contraction in cutaneous equine digital veins.

    PubMed

    Zerpa, H; Berhane, Y; Woodcock, H; Elliott, J; Bailey, S R

    2010-07-01

    A decrease in environmental temperature can directly affect the contractility of cutaneous vasculature, mediated in part by alpha(2)-adrenoceptors. Most of the cellular mechanisms underlying the cooling-enhanced contractility to alpha(2)-adrenoceptor agonists have been reported in cutaneous arteries but little information is available on cutaneous veins. To investigate the cellular mechanisms associated with the cooling-enhanced contraction to UK-14304 (alpha(2)-adrenoceptor agonist), isolated equine digital veins (EDVs) were studied at 30 degrees C and 22 degrees C. The effects of inhibitors were studied on the contractile response to UK-14304 (0.1 microM). The cooling-enhanced responses were inhibited by Rho kinase inhibitors [maximum response to UK-14304 95.2 +/- 8% of response to depolarizing Krebs solution (DKS) in control vessels cooled to 22 degrees C, compared with 31.4 +/- 6% in the presence of fasudil 1 microM and 75.8 +/- 6% with Y-27632 0.1 microM] and the effects of these inhibitors were considerably less at 30 degrees C (control response 56.4 +/- 5% of DKS; 34.9 +/- 6% with fasudil 1 microM and 50.6 +/- 9% with Y-27632 0.1 microM). Furthermore, Western blotting showed that one of the downstream targets for Rho kinase activity, ezrin/radixin/moesin, was phosphorylated after cooling and reduced by fasudil (1 microM) only at 22 degrees C. The activation of protein kinase C contributed to the contractile response, but predominantly at 30 degrees C (maximum response 82.3 +/- 9% of DKS for control; 57.7 +/- 10% in the presence of chelerythrine 10 microM) with no significant effect at 22 degrees C. The reduction of the response at 22 degrees C by antioxidants, rotenone (14% reduction), and tempol (21% reduction) suggested the contribution of reactive oxygen species (ROS). No evidence was obtained to support the participation of tyrosine kinase. These data demonstrate that Rho kinase activation and the production of ROS contributes to the cooling

  19. 75 FR 52734 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Cooling...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-27

    ... location, design, construction and capacity of CWISs at that facility reflect the best technology available... establishes requirements applicable to the location, design, construction, and capacity of CWISs at Phase II... withdraws from waters of the U.S. for cooling purposes, and have a design intake flow of 50 million...

  20. Emerging Vocabulary Learning: From a Perspective of Activities Facilitated by Mobile Devices

    ERIC Educational Resources Information Center

    Hu, Zengning

    2013-01-01

    This paper examines the current mobile vocabulary learning practice to discover how far mobile devices are being used to support vocabulary learning. An activity-centered perspective is undertaken, with the consideration of new practice against existing theories of learning activities including behaviorist activities, constructivist activities,…

  1. Feasibility of using a compact elliptical device to increase energy expenditure during sedentary activities

    PubMed Central

    Rovniak, Liza S.; Denlinger, LeAnn; Duveneck, Ellen; Sciamanna, Christopher N.; Kong, Lan; Freivalds, Andris; Ray, Chester A.

    2013-01-01

    Objectives This study aimed to evaluate the feasibility of using a compact elliptical device to increase energy expenditure during sedentary activities. A secondary aim was to evaluate if two accelerometers attached to the elliptical device could provide reliable and valid assessments of participants’ frequency and duration of elliptical device use. Design Physically inactive adults (n = 32, age range = 25–65) were recruited through local advertisements and selected using stratified random sampling based on sex, body mass index (BMI), and age. Methods Indirect calorimetry was used to assess participants’ energy expenditure while seated and while using the elliptical device at a self-selected intensity level. Participants also self-reported their interest in using the elliptical device during sedentary activities. Two Actigraph GT3X accelerometers were attached to the elliptical device to record time-use patterns. Results Participants expended a median of 179.1 kilocalories per hour while using the elliptical device (range = 108.2–269.0), or a median of 87.9 more kilocalories (range = 19.7–178.6) than they would expend per hour of sedentary sitting. Participants reported high interest in using the elliptical device during TV watching and computer work, but relatively low interest in using the device during office meetings. Women reported greater interest in using the elliptical device than men. The two accelerometers recorded identical time-use patterns on the elliptical device and demonstrated concurrent validity with time-stamped computer records. Conclusions Compact elliptical devices could increase energy expenditure during sedentary activities, and may provide proximal environmental cues for increasing energy expenditure across multiple life domains. PMID:24035273

  2. Stochastic Cooling

    SciTech Connect

    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.

  3. Advanced lightweight cooling-garment technology: functional improvements in thermosensitive patients with multiple sclerosis.

    PubMed

    Meyer-Heim, A; Rothmaier, M; Weder, M; Kool, J; Schenk, P; Kesselring, J

    2007-03-01

    Cooling of thermosensitive patients with multiple sclerosis (MS) can improve clinical symptoms. In order to study the effectiveness of an advanced lightweight cooling-garment technology based on aquatic evaporation, a single-blinded balanced crossover study was performed on 20 patients with an Expanded Disability Status Scale score < or =6.5. The results using a tight-cuff cooling-garment prototype for peripheral cooling suggest improvement of a timed-walking test, leg-strength, fine-motor skills and subjective benefits. Preliminary data of the heart rate variability (HRV) including six patients suggest that the MS patients show an abnormal HRV after sham condition, which is normalized after cooling. Technical information was gained about the cooling activity and the practicability and handling of the device. These encouraging findings promote further adaptations of the prototype to increase its cooling properties and ameliorate the practicability of the cooling garment.

  4. Refrigerant directly cooled capacitors

    DOEpatents

    Hsu, John S.; Seiber, Larry E.; Marlino, Laura D.; Ayers, Curtis W.

    2007-09-11

    The invention is a direct contact refrigerant cooling system using a refrigerant floating loop having a refrigerant and refrigeration devices. The cooling system has at least one hermetic container disposed in the refrigerant floating loop. The hermetic container has at least one electronic component selected from the group consisting of capacitors, power electronic switches and gating signal module. The refrigerant is in direct contact with the electronic component.

  5. Haptic device development based on electro static force of cellulose electro active paper

    NASA Astrophysics Data System (ADS)

    Yun, Gyu-young; Kim, Sang-Youn; Jang, Sang-Dong; Kim, Dong-Gu; Kim, Jaehwan

    2011-04-01

    Haptic is one of well-considered device which is suitable for demanding virtual reality applications such as medical equipment, mobile devices, the online marketing and so on. Nowadays, many of concepts for haptic devices have been suggested to meet the demand of industries. Cellulose has received much attention as an emerging smart material, named as electro-active paper (EAPap). The EAPap is attractive for mobile haptic devices due to its unique characteristics in terms of low actuation power, suitability for thin devices and transparency. In this paper, we suggest a new concept of haptic actuator with the use of cellulose EAPap. Its performance is evaluated depending on various actuation conditions. As a result, cellulose electrostatic force actuator shows a large output displacement and fast response, which is suitable for mobile haptic devices.

  6. Hydronic rooftop cooling systems

    DOEpatents

    Bourne, Richard C.; Lee, Brian Eric; Berman, Mark J.

    2008-01-29

    A roof top cooling unit has an evaporative cooling section that includes at least one evaporative module that pre-cools ventilation air and water; a condenser; a water reservoir and pump that captures and re-circulates water within the evaporative modules; a fan that exhausts air from the building and the evaporative modules and systems that refill and drain the water reservoir. The cooling unit also has a refrigerant section that includes a compressor, an expansion device, evaporator and condenser heat exchangers, and connecting refrigerant piping. Supply air components include a blower, an air filter, a cooling and/or heating coil to condition air for supply to the building, and optional dampers that, in designs that supply less than 100% outdoor air to the building, control the mixture of return and ventilation air.

  7. 78 FR 41065 - Agency Information Collection Activities; Proposed Collection; Comment Request; Medical Devices...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-09

    ... HUMAN SERVICES Food and Drug Administration Agency Information Collection Activities; Proposed Collection; Comment Request; Medical Devices; Third-Party Review Under the Food and Drug Administration Modernization Act AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and...

  8. Water Pollution Scrubber Activity Simulates Pollution Control Devices.

    ERIC Educational Resources Information Center

    Kennedy, Edward C., III; Waggoner, Todd C.

    2003-01-01

    A laboratory activity caused students to think actively about water pollution. The students realized that it would be easier to keep water clean than to remove pollutants. They created a water scrubbing system allowing them to pour water in one end and have it emerge clean at the other end. (JOW)

  9. Fabric-based integrated energy devices for wearable activity monitors.

    PubMed

    Jung, Sungmook; Lee, Jongsu; Hyeon, Taeghwan; Lee, Minbaek; Kim, Dae-Hyeong

    2014-09-01

    A wearable fabric-based integrated power-supply system that generates energy triboelectrically using human activity and stores the generated energy in an integrated supercapacitor is developed. This system can be utilized as either a self-powered activity monitor or as a power supply for external wearable sensors. These demonstrations give new insights for the research of wearable electronics.

  10. Comparing wearable devices with wet and textile electrodes for activity recognition.

    PubMed

    Lokare, Namita; Gonzalez, Laura; Lobaton, Edgar

    2016-08-01

    This paper explores the idea of identifying activities from muscle activation which is captured by wearable ECG recording devices that use wet and textile electrodes. Most of the devices available today filter out the high frequency components to retain only the signal related to an ECG. We explain how the high frequency components that correspond to muscle activation can be extracted from the recorded signal and can be used to identify activities. We notice that is possible to obtain good performance for both the wet and dry electrodes. However, we observed that signals from the dry textile electrodes introduce less artifacts associated with muscle activation.

  11. A Thermal Physiological Comparison of Two HazMat Protective Ensembles With and Without Active Convective Cooling

    NASA Technical Reports Server (NTRS)

    Williamson, Rebecca; Carbo, Jorge; Luna, Bernadette; Webbon, Bruce W.

    1998-01-01

    Wearing impermeable garments for hazardous materials clean up can often present a health and safety problem for the wearer. Even short duration clean up activities can produce heat stress injuries in hazardous materials workers. It was hypothesized that an internal cooling system might increase worker productivity and decrease likelihood of heat stress injuries in typical HazMat operations. Two HazMat protective ensembles were compared during treadmill exercise. The different ensembles were created using two different suits: a Trelleborg VPS suit representative of current HazMat suits and a prototype suit developed by NASA engineers. The two life support systems used were a current technology Interspiro Spirolite breathing apparatus and a liquid air breathing system that also provided convective cooling. Twelve local members of a HazMat team served as test subjects. They were fully instrumented to allow a complete physiological comparison of their thermal responses to the different ensembles. Results showed that cooling from the liquid air system significantly decreased thermal stress. The results of the subjective evaluations of new design features in the prototype suit were also highly favorable. Incorporation of these new design features could lead to significant operational advantages in the future.

  12. Measurements of the PLT and PDX device activation

    SciTech Connect

    Stavely, J.; Barnes, C.W.; Chrien, R.E.; Strachan, J.D.

    1981-09-01

    Measurements of the activation levels around the PLT and PDX tokamaks have been made using a Ge(Li) gamma spectrometer and a Geiger counter. The activation results from radiation induced in the plasma by 14 MeV neutrons from the d(t,n)..cap alpha.. fusion reaction, 14.7 MeV protons from the d(/sup 3/He,p)..cap alpha.. fusion reaction, 10 ..-->.. 20 MeV hard x-rays from runaway electron induced bremmstrahlung, and 2.5 MeV neutrons from the d(d,n)/sup 3/He fusion reaction. The magnitude of the activation is compared to that predicted for PDX on the basis of one-dimensional activation codes.

  13. Active devices based on organic semiconductors for wearable applications.

    PubMed

    Barbaro, Massimo; Caboni, Alessandra; Cosseddu, Piero; Mattana, Giorgio; Bonfiglio, Annalisa

    2010-05-01

    Plastic electronics is an enabling technology for obtaining active (transistor based) electronic circuits on flexible and/or nonplanar surfaces. For these reasons, it appears as a perfect candidate to promote future developments of wearable electronics toward the concept of fabrics and garments made by functional (in this case, active electronic) yarns. In this paper, a panoramic view of recent achievements and future perspectives is given.

  14. An adaptive Hidden Markov Model for activity recognition based on a wearable multi-sensor device

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human activity recognition is important in the study of personal health, wellness and lifestyle. In order to acquire human activity information from the personal space, many wearable multi-sensor devices have been developed. In this paper, a novel technique for automatic activity recognition based o...

  15. Variability in cold front activities modulating cool-season evaporation from a southern inland water in the USA

    NASA Astrophysics Data System (ADS)

    Liu, Heping; Blanken, Peter D.; Weidinger, Tamas; Nordbo, Annika; Vesala, Timo

    2011-04-01

    Understanding seasonal variations in the evaporation of inland waters (e.g., lakes and reservoirs) is important for water resource management as well as the prediction of the hydrological cycles in response to climate change. We analyzed eddy covariance-based evaporation measurements from the Ross Barnett Reservoir (32°26'N, 90°02'W which is always ice-free) in central Mississippi during the cool months (i.e., September-March) of 2007 and 2008, and found that the variability in cold front activities (i.e., passages of cold fronts and cold/dry air masses behind cold fronts) played an important role in modulating the exchange of sensible (H) and latent (λE) heat fluxes. Our analysis showed that 2007's warmer cool season had smaller mean H and λE than 2008's cooler cool season. This implies that the warmer cool season did not accelerate evaporation and heat exchange between the water surface and the atmosphere. Instead, more frequent cold fronts and longer periods of cold/dry air masses behind the cold fronts in 2008 resulted in overall larger H and λE as compared with 2007, this primarily taking the form of sporadic short-term rapid 'pulses' of H and λE losses from the water's surface. These results suggest that future climate-induced changes in frequency of cold fronts and the meteorological properties of the air masses behind cold fronts (e.g., wind speeds, temperature, and humidity), rather than other factors of climate change, would produce significant variations in the water surface's energy fluxes and subsequent evaporation rates.

  16. Warm and Cool Dinosaurs.

    ERIC Educational Resources Information Center

    Mannlein, Sally

    2001-01-01

    Presents an art activity in which first grade students draw dinosaurs in order to learn about the concept of warm and cool colors. Explains how the activity also helped the students learn about the concept of distance when drawing. (CMK)

  17. Re-active Passive (RAP) Devices for Control of Noise Transmission through a Panel

    NASA Technical Reports Server (NTRS)

    Carneal, James P.; Giovanardi, Marco; Fuller, Chris R.; Palumbo, Daniel L.

    2008-01-01

    Re-Active Passive (RAP) devices have been developed to control low frequency (<1000 Hz) noise transmission through a panel. These devices use a combination of active, re-active, and passive technologies packaged into a single unit to control a broad frequency range utilizing the strength of each technology over its best suited frequency range. The RAP device uses passive constrained layer damping to cover the relatively high frequency range (>200 Hz), reactive distributed vibration absorber) to cover the medium frequency range (75 to 250 Hz), and active control for controlling low frequencies (<200 Hz). The device was applied to control noise transmission through a panel mounted in a transmission loss test facility. Experimental results are presented for the bare panel, and combinations of passive treatment, reactive treatment, and active control. Results indicate that three RAP devices were able to increase the overall broadband (15-1000 Hz) transmission loss by 9.4 dB. These three devices added a total of 285 grams to the panel mass of 6.0 kg, or approximately 5%, not including control electronics.

  18. Study of a fail-safe abort system for an actively cooled hypersonic aircraft: Computer program documentation

    NASA Technical Reports Server (NTRS)

    Haas, L. A., Sr.

    1976-01-01

    The Fail-Safe Abort System TEMPerature Analysis Program, (FASTEMP), user's manual is presented. This program was used to analyze fail-safe abort systems for an actively cooled hypersonic aircraft. FASTEMP analyzes the steady state or transient temperature response of a thermal model defined in rectangular, cylindrical, conical and/or spherical coordinate system. FASTEMP provides the user with a large selection of subroutines for heat transfer calculations. The various modes of heat transfer available from these subroutines are: heat storage, conduction, radiation, heat addition or generation, convection, and fluid flow.

  19. Radiofrequency identification and medical devices: the regulatory framework on electromagnetic compatibility. Part II: active implantable medical devices.

    PubMed

    Mattei, Eugenio; Censi, Federica; Triventi, Michele; Bartolini, Pietro; Calcagnini, Giovanni

    2012-05-01

    The number and the types of electromagnetic emitters to which patients with active implantable medical devices (AIMD) are exposed to in their daily activities have proliferated over the last decade. Radiofrequency identification (RFID) is an example of wireless technology applied in many fields. The interaction between RFID emitters and AIMD is an important issue for patients, industry and regulators, because of the risks associated with such interactions. The different AIMDs refer to different standards that address the electromagnetic immunity issue in different ways. Indeed, different test setups, immunity levels and rationales are used to guarantee that AIMDs are immune to electromagnetic nonionizing radiation. In this article, the regulatory framework concerning electromagnetic compatibility between RFID systems and AIMDs is analyzed to understand whether and how the application of the current AIMD standards allows for the effective control of the possible risks associated with RFID technology.

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

    NASA Astrophysics Data System (ADS)

    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

  1. Self pumping magnetic cooling

    NASA Astrophysics Data System (ADS)

    Chaudhary, V.; Wang, Z.; Ray, A.; Sridhar, I.; Ramanujan, R. V.

    2017-01-01

    Efficient thermal management and heat recovery devices are of high technological significance for innovative energy conservation solutions. We describe a study of a self-pumping magnetic cooling device, which does not require external energy input, employing Mn-Zn ferrite nanoparticles suspended in water. The device performance depends strongly on magnetic field strength, nanoparticle content in the fluid and heat load temperature. Cooling (ΔT) by ~20 °C and ~28 °C was achieved by the application of 0.3 T magnetic field when the initial temperature of the heat load was 64 °C and 87 °C, respectively. These experiments results were in good agreement with simulations performed with COMSOL Multiphysics. Our system is a self-regulating device; as the heat load increases, the magnetization of the ferrofluid decreases; leading to an increase in the fluid velocity and consequently, faster heat transfer from the heat source to the heat sink.

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

    NASA Astrophysics Data System (ADS)

    Bardy, Erik; Mollendorf, Joseph; Pendergast, David

    2008-02-01

    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 °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 °C). During immersion, the tubesuit was perfused with 30 °C water at a flow rate of 0.5 L min-1 to six individual body regions. An attempt was made to keep skin temperatures below 42 °C in hot water (>30 °C) and elevated but below 32 °C in cold water (<20 °C). A skin temperature of 32 °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 °C to 40 °C water, respectively. In the 3 mm wetsuit -462 to 342 W was necessary in 10 °C to 40 °C water, respectively. It was therefore concluded that a diver at rest can be kept in thermal balance in 10-40 °C water with active heating and cooling.

  3. On a portable memory device for physical activities and informations of maternal perception.

    PubMed

    Hasegawa, T; Horio, H; Makikawa, M; Bunki, H; Sasaki, K; Utsu, M; Sakakibara, S; Kanzaki, T; Kobayashi, H; Chiba, Y

    1988-01-01

    The condition of patients must be known to attending doctors for adequate management of a disease, particularly of high risk pregnancy. For this purpose, we have developed a portable computerized disease condition memory device to record the physical activities with maternal perception of fetal movement and uterine condition in daily life, both at home and during work. This device taken out by the patient is a small battery-driven CMOS 8 bit computer system (size: 107 x 80 x 30 mm, 240 g) and is equipped with push-botton switches on the upper side and a mercury switch inside it. The time of maternal perception of fetal movement and uterine contraction are recorded by the patient pressing the corresponding switch. Meanwhile the mercury switch serves as a acceleration sensor and the physical activities were measured by counting ON-OFF actions of the mercury switch caused by her movements. Consequently, the device has recorded physical activities automatically by wearing this unit all day long. The continuously recordable time is more than two weeks. The evaluation about the sensitivity of physical activity measurement has indicated that the mercury switch sensor was well related to the oxygen consumption rate in rest and mild exercise. Using this device to five pregnant women, the data showed the quantitative difference in physical activities between rest in bed and normal home life, and daily changes could be clearly observed. From these results, the physical activities and the condition of the patient in daily life can be followed by this device.

  4. High energy electron cooling

    SciTech Connect

    Parkhomchuk, V.

    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.

  5. Design of a continuous passive and active motion device for hand rehabilitation.

    PubMed

    Birch, B; Haslam, E; Heerah, I; Dechev, N; Park, E J

    2008-01-01

    This paper presents the design of a novel, portable device for hand rehabilitation. The device provides for CPM (continuous passive motion) and CAM (continuous active motion) hand rehabilitation for patients recovering from damage such as flexor tendon repair and strokes. The device is capable of flexing/extending the MCP (metacarpophalangeal) and PIP (proximal interphalangeal) joints through a range of motion of 0 degrees to 90 degrees for both the joints independently. In this way, typical hand rehabilitation motions such as intrinsic plus, intrinsic minus, and a fist can be achieved without the need of any splints or attachments. The CPM mode is broken into two subgroups. The first mode is the use of preset waypoints for the device to cycle through. The second mode involves motion from a starting position to a final position, but senses the torque from the user during the cycle. Therefore the user can control the ROM by resisting when they are at the end of the desired motion. During the CPM modes the device utilizes a minimum jerk trajectory model under PD control, moving smoothly and accurately between preselected positions. CAM is the final mode where the device will actively resist the movement of the user. The user moves from a start to end position while the device produces a torque to resist the motion. This active resistance motion is a unique ability designed to mimic the benefits of a human therapist. Another unique feature of the device is its ability to independently act on both the MCP and PIP joints. The feedback sensing built into the device makes it capable of offering a wide and flexible range of rehabilitation programs for the hand.

  6. AHA! A Cool Salt Water/Density Activity--The Joy of Designing a Simple Experiment.

    ERIC Educational Resources Information Center

    Carlson, Gaylen R.

    1998-01-01

    Describes two science activities concerning water density and shares an idea for combining these activities into a third, completely new activity. Demonstrates the joy of rekindling the spirit of scientific thinking in a typical classroom. (PVD)

  7. Monolithic microwave integrated circuit devices for active array antennas

    NASA Technical Reports Server (NTRS)

    Mittra, R.

    1984-01-01

    Two different aspects of active antenna array design were investigated. The transition between monolithic microwave integrated circuits and rectangular waveguides was studied along with crosstalk in multiconductor transmission lines. The boundary value problem associated with a discontinuity in a microstrip line is formulated. This entailed, as a first step, the derivation of the propagating as well as evanescent modes of a microstrip line. The solution is derived to a simple discontinuity problem: change in width of the center strip. As for the multiconductor transmission line problem. A computer algorithm was developed for computing the crosstalk noise from the signal to the sense lines. The computation is based on the assumption that these lines are terminated in passive loads.

  8. Differential rotation of cool active stars: the case of intermediate rotators

    NASA Astrophysics Data System (ADS)

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

    2002-08-01

    In this paper, we present a new method for measuring the surface differential rotation of cool stars with rotation periods of a few days, for which the sparse phase coverage achievable from single-site observations generally prevents the use of more conventional techniques. The basic idea underlying this new analysis is to obtain the surface differential rotation pattern that minimizes the information content of the reconstructed Doppler image through a simultaneous fit of all available data. Simulations demonstrate that the performance of this new method in the case of cool stars is satisfactory for a variety of observing strategies. Differential rotation parameters can be recovered reliably as long as the total data set spans at least 4 per cent of the time for the equator to lap the pole by approximately one complete cycle. We find in particular that these results hold for potentially complex spot distributions (as long as they include a mixture of low- and high-latitude features), and for various stellar inclination angles and rotation velocities. Such measurements can be obtained from either unpolarized or polarized data sets, provided their signal-to-noise ratio is larger than approximately 500 and 5000 per 2kms-1 spectral bin, respectively. This method should therefore be very useful for investigating differential rotation in a much larger sample of objects than what has been possible up to now, and should hence give us the opportunity of studying how differential rotation reacts to various phenomena operating in stellar convective zones, such as tidal effects or dynamo magnetic field generation.

  9. Cooling dissociates glucose-induced insulin release from electrical activity and cation fluxes in rodent pancreatic islets.

    PubMed Central

    Atwater, I; Goncalves, A; Herchuelz, A; Lebrun, P; Malaisse, W J; Rojas, E; Scott, A

    1984-01-01

    Insulin release and beta-cell membrane potentials in response to glucose at 37 and 27 degrees C have been measured simultaneously in single, micro-dissected, perifused islets of Langerhans from normal mice. Insulin release and 45Ca outflow in response to glucose at 37 and 27 degrees C have been measured simultaneously from perfused islets isolated by collagenase digestion from normal rats. The effect of cooling on beta-cell membrane potassium permeability was assessed by changes in measured membrane potential and input resistance (in the mouse) and by changes in 86Rb outflow (in the rat). Resting and active beta-cell membrane parameters (i.e. membrane potential, spike frequency, input resistance, 45Ca outflow and 86Rb outflow), in both mouse and rat islets, were affected only slightly by cooling to 27 degrees C, with temperature coefficients of 2 or lower. At 27 degrees C glucose-stimulated insulin release was inhibited completely in mouse islets and almost completely in rat islets. The temperature coefficients in both preparations were greater than 5. It is concluded that beta-cell electrical activity and changes in membrane permeability induced by glucose are not consequences of insulin release. PMID:6371219

  10. Effects of a Physical Education Supportive Curriculum and Technological Devices on Physical Activity

    ERIC Educational Resources Information Center

    Clapham, Emily Dean; Sullivan, Eileen C.; Ciccomascolo, Lori E.

    2015-01-01

    The purpose of this study was to examine the effects of a physical education supportive curriculum and technological devices, heart rate monitor (HRM) and pedometer (PED), on physical activity. A single-subject ABAB research design was used to examine amount and level of participation in physical activity among 106 suburban fourth and fifth…

  11. Cooling using complimentary tapered plenums

    DOEpatents

    Hall, Shawn Anthony

    2006-08-01

    Where a fluid cooling medium cools a plurality of heat-producing devices arranged in a row along a generalized coordinate direction, with a space between each adjacent pair of devices, each space may have a partition that defines a boundary between a first plenum and a second plenum. The first plenum carries cooling medium across an entrance and thence into a first heat-producing device located on a first side of the partition facing the first plenum. The second plenum carries cooling medium away from a second heat-producing device located on a second side of the partition facing the second plenum and thence across an exit. The partition is disposed so that the first plenum becomes smaller in cross-sectional area as distance increases from the entrance, and the second plenum becomes larger in cross sectional area as distance decreases toward the exit.

  12. Complement activation by candidate biomaterials of an implantable microfabricated medical device.

    PubMed

    Sokolov, Andrey; Hellerud, Bernt C; Pharo, Anne; Johannessen, Erik A; Mollnes, Tom E

    2011-08-01

    Implantable devices realized by microfabrication have introduced a new class of potential biomaterials whose properties would need to be assessed. Such devices include sensors for measuring biological substances like glucose. Thus, 14 different candidate materials intended for design of such a device were investigated with respect to their complement activation potential in human serum. The fluid-phase activation was measured by the products C4d, Bb, C3bc, and the terminal complement complex (TCC), whereas solid-phase activation was measured by deposition of TCC on the material surfaces. No fluid-phase activation was found for materials related to the capsule, carrier, or sealing. Fluid-phase activation was, however, triggered to a various extent in three of the four nanoporous membranes (cellulose, polyamide, and aluminium oxide), whereas polycarbonate was rendered inactive. Solid-phase activation discriminated more sensitively between all the materials, revealing that the capsule candidate polydimethylsiloxane and sealing candidate silicone 3140 were highly compatible, showing significantly lower TCC deposition than the negative control (p < 0.01). Three of the candidate materials were indifferent, whereas the remaining nine showed significantly higher deposition of TCC than the negative control (p < 0.01). In conclusion, complement activation, in particular when examined on the solid phase, discriminated well between the different candidate materials tested and could be used as a guide for the selection of the best-suited materials for further investigation and development of the device.

  13. A Robust and Device-Free System for the Recognition and Classification of Elderly Activities

    PubMed Central

    Li, Fangmin; Al-qaness, Mohammed Abdulaziz Aide; Zhang, Yong; Zhao, Bihai; Luan, Xidao

    2016-01-01

    Human activity recognition, tracking and classification is an essential trend in assisted living systems that can help support elderly people with their daily activities. Traditional activity recognition approaches depend on vision-based or sensor-based techniques. Nowadays, a novel promising technique has obtained more attention, namely device-free human activity recognition that neither requires the target object to wear or carry a device nor install cameras in a perceived area. The device-free technique for activity recognition uses only the signals of common wireless local area network (WLAN) devices available everywhere. In this paper, we present a novel elderly activities recognition system by leveraging the fluctuation of the wireless signals caused by human motion. We present an efficient method to select the correct data from the Channel State Information (CSI) streams that were neglected in previous approaches. We apply a Principle Component Analysis method that exposes the useful information from raw CSI. Thereafter, Forest Decision (FD) is adopted to classify the proposed activities and has gained a high accuracy rate. Extensive experiments have been conducted in an indoor environment to test the feasibility of the proposed system with a total of five volunteer users. The evaluation shows that the proposed system is applicable and robust to electromagnetic noise. PMID:27916948

  14. Active mode-locked lasers and other photonic devices using electro-optic whispering gallery mode resonators

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey B. (Inventor); Ilchenko, Vladimir (Inventor); Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor)

    2006-01-01

    Techniques and devices using whispering gallery mode (WGM) optical resonators, where the optical materials of the WGM resonators exhibit an electro-optical effect to perform optical modulation. Examples of actively mode-locked lasers and other devices are described.

  15. THE EFFECT OF DOUBLE VERSUS SINGLE OSCILLATING EXERCISE DEVICES ON TRUNK AND LIMB MUSCLE ACTIVATION

    PubMed Central

    Arora, Shruti; Button, Duane C.; Basset, Fabien A.

    2013-01-01

    Purpose/Background: Proper strengthening of the core and upper extremities is important for muscular health, performance, and rehabilitation. Exercise devices have been developed that attempt to disrupt the center of gravity in order to activate the trunk stabilizing muscles. The objective of this study was to analyze the trunk and shoulder girdle muscle activation with double and single oscillating exercise devices (DOD and SOD respectively) in various planes. Methods: Twelve male subjects performed three interventions using both devices under randomized conditions: single-handed vertical orientation of DOD and SOD to produce 1) medio-lateral oscillation in the frontal plane 2) dorso-ventral oscillation in the sagittal plane and 3) single-handed horizontal orientation for superior and inferior oscillation in the transverse plane. Electromyographic (EMG) activity during the interventions of the anterior deltoid, triceps brachii, biceps brachii, forearm flexors as well as lower abdominal and back stabilizer muscles was collected, and were normalized to maximal voluntary contractions. A two way repeated measures ANOVA (2x3) was conducted to assess the influence of the devices and movement planes on muscle activation. Results: The DOD provided 35.9%, 40.8%, and 52.3% greater anterior deltoid, transverse abdominus (TA)/internal oblique (IO) and lumbo-sacral erector spinae (LSES) activation than did the SOD respectively. Effect size calculations revealed that these differences were of moderate to large magnitude (0.86, 0.48, and 0.61 respectively). There were no significant differences in muscular activation achieved between devices for the triceps brachii, biceps brachii and forearm flexor muscles. Exercise in the transverse plane resulted in 30.5%, 29.5%, and 19.5% greater activation than the sagittal and 21.8%, 17.2%, and 26.3% greater activation than the frontal plane for the anterior deltoid, TA/IO and LSES respectively. Conclusions: A DOD demonstrated greater

  16. Device and software used to carry out Cyclic Neutron Activation Analysis

    NASA Astrophysics Data System (ADS)

    Castro-García, M. P.; Rey-Ronco, M. A.; Alonso-Sánchez, T.

    2014-11-01

    This paper discusses the device and software used to carry out Cyclic Neutron Activation Analysis (CNAA). The aim of this investigation is defining through this device the fluorite content present on different samples from fluorspar concentration plant through the DGNAA (Delayed Gamma Neutron Activation Analysis) method. This device is made of americium-beryllium neutron source, NaI (2"×2") and BGO (2"×2") gamma rays detectors, multichannel and an automatic mechanism which moves the samples from activation and reading position. This mechanism is controlled by a software which allows moving the samples precisely and in a safe way (~ms), which it is very useful when the radioactive isotopes have to be detected with a half time less than 8s.

  17. 24 Hours of Sleep, Sedentary Behavior, and Physical Activity with Nine Wearable Devices

    PubMed Central

    Rosenberger, Mary E.; Buman, Matthew P.; Haskell, William L.; McConnell, Michael V.; Carstensen, Laura L.

    2015-01-01

    Getting enough sleep, exercising and limiting sedentary activities can greatly contribute to disease prevention and overall health and longevity. Measuring the full 24-hour activity cycle - sleep, sedentary behavior (SED), light intensity physical activity (LPA) and moderate-to-vigorous physical activity (MVPA) - may now be feasible using small wearable devices. PURPOSE This study compares nine devices for accuracy in 24-hour activity measurement. METHODS Adults (N=40, 47% male) wore nine devices for 24-hours: Actigraph GT3X+, activPAL, Fitbit One, GENEactiv, Jawbone Up, LUMOback, Nike Fuelband, Omron pedometer, and Z-Machine. Comparisons (to standards) were made for total sleep time (Z-machine), time spent in SED (activPAL), LPA (GT3x+), MVPA (GT3x+), and steps (Omron). Analysis included mean absolute percent error, equivalence testing, and Bland-Altman plots. RESULTS Error rates ranged from 8.1–16.9% for sleep; 9.5–65.8% for SED; 19.7–28.0% for LPA; 51.8–92% for MVPA; and 14.1–29.9% for steps. Equivalence testing indicated only two comparisons were significantly equivalent to standards: the LUMOback for sedentary behavior and the GT3X+ for sleep. Bland-Altman plots indicated GT3X+ had the closest measurement for sleep, LUMOback for sedentary behavior, GENEactiv for LPA, Fitbit for MVPA and GT3X+ for steps. CONCLUSIONS Currently, no device accurately captures activity data across the entire 24-hour day, but the future of activity measurement should aim for accurate 24-hour measurement as a goal. Researchers should continue to select measurement devices based on their primary outcomes of interest. PMID:26484953

  18. Non-volatile memory devices with redox-active diruthenium molecular compound

    NASA Astrophysics Data System (ADS)

    Pookpanratana, S.; Zhu, H.; Bittle, E. G.; Natoli, S. N.; Ren, T.; Richter, C. A.; Li, Q.; Hacker, C. A.

    2016-03-01

    Reduction-oxidation (redox) active molecules hold potential for memory devices due to their many unique properties. We report the use of a novel diruthenium-based redox molecule incorporated into a non-volatile Flash-based memory device architecture. The memory capacitor device structure consists of a Pd/Al2O3/molecule/SiO2/Si structure. The bulky ruthenium redox molecule is attached to the surface by using a ‘click’ reaction and the monolayer structure is characterized by x-ray photoelectron spectroscopy to verify the Ru attachment and molecular density. The ‘click’ reaction is particularly advantageous for memory applications because of (1) ease of chemical design and synthesis, and (2) provides an additional spatial barrier between the oxide/silicon to the diruthenium molecule. Ultraviolet photoelectron spectroscopy data identified the energy of the electronic levels of the surface before and after surface modification. The molecular memory devices display an unsaturated charge storage window attributed to the intrinsic properties of the redox-active molecule. Our findings demonstrate the strengths and challenges with integrating molecular layers within solid-state devices, which will influence the future design of molecular memory devices.

  19. Active control of all-fibre graphene devices with electrical gating

    PubMed Central

    Lee, Eun Jung; Choi, Sun Young; Jeong, Hwanseong; Park, Nam Hun; Yim, Woongbin; Kim, Mi Hye; Park, Jae-Ku; Son, Suyeon; Bae, Sukang; Kim, Sang Jin; Lee, Kwanil; Ahn, Yeong Hwan; Ahn, Kwang Jun; Hong, Byung Hee; Park, Ji-Yong; Rotermund, Fabian; Yeom, Dong-Il

    2015-01-01

    Active manipulation of light in optical fibres has been extensively studied with great interest because of its compatibility with diverse fibre-optic systems. While graphene exhibits a strong electro-optic effect originating from its gapless Dirac-fermionic band structure, electric control of all-fibre graphene devices remains still highly challenging. Here we report electrically manipulable in-line graphene devices by integrating graphene-based field effect transistors on a side-polished fibre. Ion liquid used in the present work critically acts both as an efficient gating medium with wide electrochemical windows and transparent over-cladding facilitating light–matter interaction. Combined study of unique features in gate-variable electrical transport and optical transition at monolayer and randomly stacked multilayer graphene reveals that the device exhibits significant optical transmission change (>90%) with high efficiency-loss figure of merit. This subsequently modifies nonlinear saturable absorption characteristics of the device, enabling electrically tunable fibre laser at various operational regimes. The proposed device will open promising way for actively controlled optoelectronic and nonlinear photonic devices in all-fibre platform with greatly enhanced graphene–light interaction. PMID:25897687

  20. Active control of all-fibre graphene devices with electrical gating.

    PubMed

    Lee, Eun Jung; Choi, Sun Young; Jeong, Hwanseong; Park, Nam Hun; Yim, Woongbin; Kim, Mi Hye; Park, Jae-Ku; Son, Suyeon; Bae, Sukang; Kim, Sang Jin; Lee, Kwanil; Ahn, Yeong Hwan; Ahn, Kwang Jun; Hong, Byung Hee; Park, Ji-Yong; Rotermund, Fabian; Yeom, Dong-Il

    2015-04-21

    Active manipulation of light in optical fibres has been extensively studied with great interest because of its compatibility with diverse fibre-optic systems. While graphene exhibits a strong electro-optic effect originating from its gapless Dirac-fermionic band structure, electric control of all-fibre graphene devices remains still highly challenging. Here we report electrically manipulable in-line graphene devices by integrating graphene-based field effect transistors on a side-polished fibre. Ion liquid used in the present work critically acts both as an efficient gating medium with wide electrochemical windows and transparent over-cladding facilitating light-matter interaction. Combined study of unique features in gate-variable electrical transport and optical transition at monolayer and randomly stacked multilayer graphene reveals that the device exhibits significant optical transmission change (>90%) with high efficiency-loss figure of merit. This subsequently modifies nonlinear saturable absorption characteristics of the device, enabling electrically tunable fibre laser at various operational regimes. The proposed device will open promising way for actively controlled optoelectronic and nonlinear photonic devices in all-fibre platform with greatly enhanced graphene-light interaction.

  1. Non-volatile Memory Devices with Redox-active Diruthenium Molecular Compound

    PubMed Central

    Pookpanratana, S.; Zhu, H.; Bittle, E. G.; Natoli, S. N.; Ren, T.; Richter, C. A; Li, Q.; Hacker, C. A.

    2016-01-01

    Reduction-oxidation (redox) active molecules hold potential for memory devices due to their many unique properties. We report the use of a novel diruthenium-based redox molecule incorporated into a non-volatile Flash-based memory device architecture. The memory capacitor device structure consists of a Pd/Al2O3/molecule/SiO2/Si structure. The bulky ruthenium redox molecule is attached to the surface by using a “click” reaction and the monolayer structure is characterized by X-ray photoelectron spectroscopy to verify the Ru attachment and molecular density. The “click” reaction is particularly advantageous for memory applications because of (1) ease of chemical design and synthesis, and (2) provides an additional spatial barrier between the oxide/silicon to the diruthenium molecule. Ultraviolet photoelectron spectroscopy data identified the energy of the electronic levels of the surface before and after surface modification. The molecular memory devices display an unsaturated charge storage window attributed to the intrinsic properties of the redox-active molecule. Our findings demonstrate the strengths and challenges with integrating molecular layers within solid-state devices, which will influence the future design of molecular memory devices. PMID:26871549

  2. Application of a Z-Shaped Umbilical Incision and a Saline-Cooled Radiofrequency Device to Single-Incision Laparoscopic Surgery for a Huge Liver Cyst: Report of a Case.

    PubMed

    Igami, Tsuyoshi; Tsuchiya, Tomonori; Ebata, Tomoki; Yokoyama, Yukihiro; Sugawara, Gen; Mizuno, Takashi; Nagino, Masato

    2015-06-01

    When compared with other diseases, few authors have reported on single-incision laparoscopic surgery (SILS) for liver cysts. We herein describe our experience with SILS for a huge liver cyst with the application of an umbilical Z-shaped incision using a gel port and a high-density monopolar saline-cooled radiofrequency device with a successful outcome. An 80-old-year woman was diagnosed with a huge liver cyst with abdominal pain. She underwent percutaneous drainage of the liver cyst and injection of both absolute ethanol and an antimicrobial agent into the liver cyst at the previous hospital. Because of re-expansion of the liver cyst and symptom recurrence, we performed SILS for the liver cyst. An umbilical Z-shaped incision was made for gel port placement. After aspiration of the cystic fluid and dissection of the thin cystic wall by laparoscopic coagulating shears, the thick cystic wall was divided using an endoscopic linear stapler to avoid bleeding and bile leakage. After wide fenestration, a high-density monopolar saline-cooled radiofrequency device was applied for the ablation of the remnant membrane of the cystic wall. All maneuvers could be performed only through the gel port. The patient was discharged 4 days after surgery and was satisfied with the cosmetic results. This case shows that the application of an umbilical Z-shaped incision using a gel port and a high-density monopolar saline-cooled radiofrequency device is useful for the accomplishment of SILS for a huge liver cyst.

  3. Phosphorylation of the cool-1/beta-Pix protein serves as a regulatory signal for the migration and invasive activity of Src-transformed cells.

    PubMed

    Feng, Qiyu; Baird, Dan; Yoo, Sungsoo; Antonyak, Marc; Cerione, Richard A

    2010-06-11

    Previously we showed that Cool-1 (Cloned out of library-1)/beta-Pix (Pak-interactive exchange factor) is phosphorylated at a specific tyrosine residue (Tyr-442) in a Src-dependent manner and serves as a dual function guanine nucleotide exchange factor (GEF)/signaling-effector for Cdc42 that is essential for transformation by Src. Here, we show that knocking-down Cool-1 or overexpressing a Cool-1 mutant that contains substitutions within its Dbl homology domain and is defective for GEF activity, inhibits Src-promoted cell migration. Similarly, the expression of a Cool-1 mutant containing a tyrosine to phenylalanine substitution at position 442, making it incapable of being phosphorylated in response to serum, epidermal growth factor (EGF), or Src, also causes a significant inhibition of the migration and invasive activity of cells expressing oncogenic Src. We further demonstrate that the phosphorylation of Cool-1 at Tyr-442 weakens its ability to bind to one of its primary interaction-partners, Cat-1 (Cool-associated tyrosine phosphosubstrate-1)/Git-1 (G protein-coupled receptor kinase-interactor-1), thus making Cat more accessible for binding to paxillin. This enables cells to alternate between states where they contain large numbers of focal complexes (i.e. conditions favoring Cool-1-Cat interactions) versus reduced numbers of focal complexes (conditions favoring Cat-paxillin interactions). Overall, these findings show that the phosphorylation-dephosphorylation cycle of Cool-1 at Tyr-442 can serve as a key regulatory signal for focal complex assembly-disassembly, and consequently, for the migration and invasive activity of Src-transformed cells.

  4. Human movement activity classification approaches that use wearable sensors and mobile devices

    NASA Astrophysics Data System (ADS)

    Kaghyan, Sahak; Sarukhanyan, Hakob; Akopian, David

    2013-03-01

    Cell phones and other mobile devices become part of human culture and change activity and lifestyle patterns. Mobile phone technology continuously evolves and incorporates more and more sensors for enabling advanced applications. Latest generations of smart phones incorporate GPS and WLAN location finding modules, vision cameras, microphones, accelerometers, temperature sensors etc. The availability of these sensors in mass-market communication devices creates exciting new opportunities for data mining applications. Particularly healthcare applications exploiting build-in sensors are very promising. This paper reviews different approaches of human activity recognition.

  5. Cool & Connected

    EPA Pesticide Factsheets

    The Cool & Connected planning assistance program helps communities develop strategies and an action plan for using broadband to promote environmentally and economically sustainable community development.

  6. Cooling wall

    SciTech Connect

    Nosenko, V.I.

    1995-07-01

    Protecting the shells of blast furnaces is being resolved by installing cast iron cooling plates. The cooling plates become non-operational in three to five years. The problem is that defects occur in manufacturing the cooling plates. With increased volume and intensity of work placed on blast furnaces, heat on the cast iron cooling plates reduces their reliability that limits the interim repair period of blast furnaces. Scientists and engineers from the Ukraine studied this problem for several years, developing a new method of cooling the blast furnace shaft called the cooling wall. Traditional cast iron plates were replaced by a screen of steel tubes, with the area between the tubes filled with fireproof concrete. Before placing the newly developed furnace shaft into operation, considerable work was completed such as theoretical calculations, design, research of temperature fields and tension. Continual testing over many years confirms the value of this research in operating blast furnaces. The cooling wall works with water cooling as well as vapor cooling and is operating in 14 blast furnaces in the Ukraine and two in Russia, and has operated for as long as 14 years.

  7. Seismic Response Control Of Structures Using Semi-Active and Passive Variable Stiffness Devices

    NASA Astrophysics Data System (ADS)

    Salem, Mohamed M. A.

    Controllable devices such as Magneto-Rheological Fluid Dampers, Electro-Rheological Dampers, and controllable friction devices have been studied extensively with limited implementation in real structures. Such devices have shown great potential in reducing seismic demands, either as smart base isolation systems, or as smart devices for multistory structures. Although variable stiffness devices can be used for seismic control of structures, the vast majority of research effort has been given to the control of damping. The primary focus of this dissertation is to evaluate the seismic control of structures using semi-active and passive variable stiffness characteristics. Smart base isolation systems employing variable stiffness devices have been studied, and two semi-active control strategies are proposed. The control algorithms were designed to reduce the superstructure and base accelerations of seismically isolated structures subject to near-fault and far-field ground motions. Computational simulations of the proposed control algorithms on the benchmark structure have shown that excessive base displacements associated with the near-fault ground motions may be better mitigated with the use of variable stiffness devices. However, the device properties must be controllable to produce a wide range of stiffness changes for an effective control of the base displacements. The potential of controllable stiffness devices in limiting the base displacement due to near-fault excitation without compromising the performance of conventionally isolated structures, is illustrated. The application of passive variable stiffness devices for seismic response mitigation of multistory structures is also investigated. A stiffening bracing system (SBS) is proposed to replace the conventional bracing systems of braced frames. An optimization process for the SBS parameters has been developed. The main objective of the design process is to maintain a uniform inter-story drift angle over the

  8. Cognition Is Cool: Can Hemispheric Activation Be Assessed by Tympanic Membrane Thermometry?

    ERIC Educational Resources Information Center

    Cherbuin, Nicolas; Brinkman, Cobie

    2004-01-01

    Hemispheric activation during cognitive tasks using functional magnetic resonance imaging (fMRI) can be difficult to interpret, uncomfortable, and is not widely available. This study investigated whether tympanic membrane thermometry could be used as a broad measure of hemispheric activation. Infrared probes measured ear temperature continuously…

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

    NASA Technical Reports Server (NTRS)

    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.

  10. Shape memory alloy-based biopsy device for active locomotive intestinal capsule endoscope.

    PubMed

    Le, Viet Ha; Hernando, Leon-Rodriguez; Lee, Cheong; Choi, Hyunchul; Jin, Zhen; Nguyen, Kim Tien; Go, Gwangjun; Ko, Seong-Young; Park, Jong-Oh; Park, Sukho

    2015-03-01

    Recently, capsule endoscopes have been used for diagnosis in digestive organs. However, because a capsule endoscope does not have a locomotive function, its use has been limited to small tubular digestive organs, such as small intestine and esophagus. To address this problem, researchers have begun studying an active locomotive intestine capsule endoscope as a medical instrument for the whole gastrointestinal tract. We have developed a capsule endoscope with a small permanent magnet that is actuated by an electromagnetic actuation system, allowing active and flexible movement in the patient's gut environment. In addition, researchers have noted the need for a biopsy function in capsule endoscope for the definitive diagnosis of digestive diseases. Therefore, this paper proposes a novel robotic biopsy device for active locomotive intestine capsule endoscope. The proposed biopsy device has a sharp blade connected with a shape memory alloy actuator. The biopsy device measuring 12 mm in diameter and 3 mm in length was integrated into our capsule endoscope prototype, where the device's sharp blade was activated and exposed by the shape memory alloy actuator. Then the electromagnetic actuation system generated a specific motion of the capsule endoscope to extract the tissue sample from the intestines. The final biopsy sample tissue had a volume of about 6 mm(3), which is a sufficient amount for a histological analysis. Consequently, we proposed the working principle of the biopsy device and conducted an in-vitro biopsy test to verify the feasibility of the biopsy device integrated into the capsule endoscope prototype using the electro-magnetic actuation system.

  11. Direct cooled power electronics substrate

    DOEpatents

    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.

  12. Multi-Sensor Fusion for Enhanced Contextual Awareness of Everyday Activities with Ubiquitous Devices

    PubMed Central

    Guiry, John J.; van de Ven, Pepijn; Nelson, John

    2014-01-01

    In this paper, the authors investigate the role that smart devices, including smartphones and smartwatches, can play in identifying activities of daily living. A feasibility study involving N = 10 participants was carried out to evaluate the devices' ability to differentiate between nine everyday activities. The activities examined include walking, running, cycling, standing, sitting, elevator ascents, elevator descents, stair ascents and stair descents. The authors also evaluated the ability of these devices to differentiate indoors from outdoors, with the aim of enhancing contextual awareness. Data from this study was used to train and test five well known machine learning algorithms: C4.5, CART, Naïve Bayes, Multi-Layer Perceptrons and finally Support Vector Machines. Both single and multi-sensor approaches were examined to better understand the role each sensor in the device can play in unobtrusive activity recognition. The authors found overall results to be promising, with some models correctly classifying up to 100% of all instances. PMID:24662406

  13. 75 FR 61494 - Agency Information Collection Activities; Proposed Collection; Comment Request; Medical Devices...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-05

    ... HUMAN SERVICES Food and Drug Administration Agency Information Collection Activities; Proposed... Symbols on Labels and in Labeling of In Vitro Diagnostic Devices Intended for Professional Use AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug Administration (FDA)...

  14. Activated T lymphocytes migrate toward the cathode of DC electric fields in microfluidic devices.

    PubMed

    Li, Jing; Nandagopal, Saravanan; Wu, Dan; Romanuik, Sean F; Paul, Kausik; Thomson, Douglas J; Lin, Francis

    2011-04-07

    Immune cell migration is a fundamental process that enables immunosurveillance and immune responses. Understanding the mechanism of immune cell migration is not only of importance to the biology of cells, but also has high relevance to cell trafficking mediated physiological processes and diseases such as embryogenesis, wound healing, autoimmune diseases and cancers. In addition to the well-known chemical concentration gradient based guiding mechanism (i.e. chemotaxis), recent studies have shown that lymphocytes can respond to applied physiologically relevant direct current (DC) electric fields by migrating toward the cathode of the fields (i.e. electrotaxis) in both in vitro and in vivo settings. In the present study, we employed two microfluidic devices allowing controlled application of electric fields inside the microfluidic channel for quantitative studies of lymphocyte electrotaxis in vitro at the single cell level. The first device is fabricated by soft-lithography and the second device is made in glass with integrated on-chip electrodes. Using both devices, we for the first time showed that anti-CD3/CD28 antibodies activated human blood T cells migrate to the cathode of the applied DC electric field. This finding is consistent with previous electrotaxis studies on other lymphocyte subsets suggesting electrotaxis is a novel guiding mechanism for immune cell migration. Furthermore, the characteristics of electrotaxis and chemotaxis of activated T cells in PDMS microfluidic devices are compared.

  15. Cool Shelter

    ERIC Educational Resources Information Center

    Praeger, Charles E.

    2005-01-01

    Amid climbing energy costs and tightening budgets, administrators at school districts, colleges and universities are looking for all avenues of potential savings while promoting sustainable communities. Cool metal roofing can save schools money and promote sustainable design at the same time. Cool metal roofing keeps the sun's heat from collecting…

  16. Postexercise Cooling Rates in 2 Cooling Jackets

    PubMed Central

    Brade, Carly; Dawson, Brian; Wallman, Karen; Polglaze, Ted

    2010-01-01

    Abstract Context: Cooling jackets are a common method for removing stored heat accumulated during exercise. To date, the efficiency and practicality of different types of cooling jackets have received minimal investigation. Objective: To examine whether a cooling jacket containing a phase-change material (PC17) results in more rapid postexercise cooling than a gel cooling jacket and a no-jacket (control) condition. Design: Randomized, counterbalanced design with 3 experimental conditions. Setting: Participants exercised at 75% V̇o2max workload in a hot climate chamber (temperature  =  35.0 ± 1.4°C, relative humidity  =  52 ± 4%) for 30 minutes, followed by postexercise cooling for 30 minutes in cool laboratory conditions (ambient temperature  =  24.9 ± 1.8°C, relative humidity  =  39% ± 10%). Patients or Other Participants: Twelve physically active men (age  =  21.3 ± 1.1 years, height  =  182.7 ± 7.1 cm, body mass  =  76.2 ± 9.5 kg, sum of 6 skinfolds  =  50.5 ± 6.9 mm, body surface area  =  1.98 ± 0.14 m2, V̇o2max  =  49.0 ± 7.0 mL·kg−1·min−1) participated. Intervention(s): Three experimental conditions, consisting of a PC17 jacket, a gel jacket, and no jacket. Main Outcome Measure(s): Core temperature (TC), mean skin temperature (TSk), and TC cooling rate (°C/min). Results: Mean peak TC postexercise was 38.49 ± 0.42°C, 38.57 ± 0.41°C, and 38.55 ± 0.40°C for the PC17 jacket, gel jacket, and control conditions, respectively. No differences were observed in peak TC cooling rates among the PC17 jacket (0.038 ± 0.007°C/min), gel jacket (0.040 ± 0.009°C/min), and control (0.034 ± 0.010°C/min, P > .05) conditions. Between trials, no differences were calculated for mean TSk cooling. Conclusions: Similar cooling rates for all 3 conditions indicate that there is no benefit associated with wearing the PC17 or gel jacket. PMID:20210620

  17. Improved Thermoelectric Devices: Advanced Semiconductor Materials for Thermoelectric Devices

    SciTech Connect

    2009-12-11

    Broad Funding Opportunity Announcement Project: Phononic Devices is working to recapture waste heat and convert it into usable electric power. To do this, the company is using thermoelectric devices, which are made from advanced semiconductor materials that convert heat into electricity or actively remove heat for refrigeration and cooling purposes. Thermoelectric devices resemble computer chips, and they manage heat by manipulating the direction of electrons at the nanoscale. These devices aren’t new, but they are currently too inefficient and expensive for widespread use. Phononic Devices is using a high-performance, cost-effective thermoelectric design that will improve the device’s efficiency and enable electronics manufacturers to more easily integrate them into their products.

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

    PubMed

    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 (p<0.05) decreases in total phenolic content (TPC), DPPH free radical scavenging activity (DPPH) in all tested CSFL's. All soaking and atmospheric boiling treatments caused significant (p<0.05) decreases in oxygen radical absorbing capacity (ORAC). However, pressure boiling and pressure steaming caused significant (p<0.05) increases in ORAC values. Steaming treatments resulted in a greater retention of TPC, DPPH, and ORAC values in all tested CSFL's as compared to boiling treatments. To obtain cooked legumes with similar palatability and firmness, pressure boiling shortened processing time as compared to atmospheric boiling, resulted in insignificant differences in TPC, DPPH for green and yellow 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.

  19. Air-cathode microbial fuel cell array: a device for identifying and characterizing electrochemically active microbes.

    PubMed

    Hou, Huijie; Li, Lei; de Figueiredo, Paul; Han, Arum

    2011-01-15

    Microbial fuel cells (MFCs) have generated excitement in environmental and bioenergy communities due to their potential for coupling wastewater treatment with energy generation and powering diverse devices. The pursuit of strategies such as improving microbial cultivation practices and optimizing MFC devices has increased power generating capacities of MFCs. However, surprisingly few microbial species with electrochemical activity in MFCs have been identified because current devices do not support parallel analyses or high throughput screening. We have recently demonstrated the feasibility of using advanced microfabrication methods to fabricate an MFC microarray. Here, we extend these studies by demonstrating a microfabricated air-cathode MFC array system. The system contains 24 individual air-cathode MFCs integrated onto a single chip. The device enables the direct and parallel comparison of different microbes loaded onto the array. Environmental samples were used to validate the utility of the air-cathode MFC array system and two previously identified isolates, 7Ca (Shewanella sp.) and 3C (Arthrobacter sp.), were shown to display enhanced electrochemical activities of 2.69 mW/m(2) and 1.86 mW/m(2), respectively. Experiments using a large scale conventional air-cathode MFC validated these findings. The parallel air-cathode MFC array system demonstrated here is expected to promote and accelerate the discovery and characterization of electrochemically active microbes.

  20. Terrestrial sensitivity to abrupt cooling recorded by aeolian activity in northwest Ohio, USA

    USGS Publications Warehouse

    Campbell, M.C.; Fisher, T.G.; Goble, R.J.

    2011-01-01

    Optically stimulated luminescence dated sand dunes and Pleistocene beach ridges in northwest Ohio are used to reconstruct landscape modification more than 5000. yr after deglaciation. Four of the OSL ages (13.3-11.1. ka) cluster around the Younger Dryas cold event, five ages (10.8-8.2. ka) cluster around the Preboreal, one young age (0.9-0.7. ka) records more recent aeolian activity, and one age of 15.1-13.1. ka dates a barrier spit in Lake Warren. In northwest Ohio, both landscape instability recorded by aeolian activity and a vegetation response recorded by pollen are coeval with the Younger Dryas. However, the climate conditions during the Preboreal resulting in aeolian activity are not recorded in the available pollen records. From this, we conclude that aeolian dunes and surfaces susceptible to deflation are sensitive to cooler, drier episodes of climate and can complement pollen data. Younger Dryas and Preboreal aged aeolian activity in northwestern Ohio coincides with aeolian records elsewhere in the Great Lakes region east of the prairie-forest ecotone. ?? 2011 University of Washington.

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

    NASA Technical Reports Server (NTRS)

    Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. M.; 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 approx equals 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 approx equals 4 Ms CDF-S and approx equals 2 Ms CDF-N and z = 0.1-0.6 in the approx equals 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 keY to B-band luminosity ratio (L(sub x) /L(sub Beta) varies as [1 +z]) since z approx equals 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z approx equals 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of approx equals1.4 -- 2.6 times larger than the average radiative cooling power from hot gas over the redshift range z approx equals 0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

  2. Devices for Self-Monitoring Sedentary Time or Physical Activity: A Scoping Review

    PubMed Central

    Loveday, Adam; Pearson, Natalie; Edwardson, Charlotte; Yates, Thomas; Biddle, Stuart JH; Esliger, Dale W

    2016-01-01

    Background It is well documented that meeting the guideline levels (150 minutes per week) of moderate-to-vigorous physical activity (PA) is protective against chronic disease. Conversely, emerging evidence indicates the deleterious effects of prolonged sitting. Therefore, there is a need to change both behaviors. Self-monitoring of behavior is one of the most robust behavior-change techniques available. The growing number of technologies in the consumer electronics sector provides a unique opportunity for individuals to self-monitor their behavior. Objective The aim of this study is to review the characteristics and measurement properties of currently available self-monitoring devices for sedentary time and/or PA. Methods To identify technologies, four scientific databases were systematically searched using key terms related to behavior, measurement, and population. Articles published through October 2015 were identified. To identify technologies from the consumer electronic sector, systematic searches of three Internet search engines were also performed through to October 1, 2015. Results The initial database searches identified 46 devices and the Internet search engines identified 100 devices yielding a total of 146 technologies. Of these, 64 were further removed because they were currently unavailable for purchase or there was no evidence that they were designed for, had been used in, or could readily be modified for self-monitoring purposes. The remaining 82 technologies were included in this review (73 devices self-monitored PA, 9 devices self-monitored sedentary time). Of the 82 devices included, this review identified no published articles in which these devices were used for the purpose of self-monitoring PA and/or sedentary behavior; however, a number of technologies were found via Internet searches that matched the criteria for self-monitoring and provided immediate feedback on PA (ActiGraph Link, Microsoft Band, and Garmin Vivofit) and sedentary time

  3. High thermoelectricpower factor in graphene/hBN devices.

    PubMed

    Duan, Junxi; Wang, Xiaoming; Lai, Xinyuan; Li, Guohong; Watanabe, Kenji; Taniguchi, Takashi; Zebarjadi, Mona; Andrei, Eva Y

    2016-12-13

    Fast and controllable cooling at nanoscales requires a combination of highly efficient passive cooling and active cooling. Although passive cooling in graphene-based devices is quite effective due to graphene's extraordinary heat conduction, active cooling has not been considered feasible due to graphene's low thermoelectric power factor. Here, we show that the thermoelectric performance of graphene can be significantly improved by using hexagonal boron nitride (hBN) substrates instead of SiO2 We find the room temperature efficiency of active cooling in the device, as gauged by the power factor times temperature, reaches values as high as 10.35 W⋅m(-1)⋅K(-1), corresponding to more than doubling the highest reported room temperature bulk power factors, 5 W⋅m(-1)⋅K(-1), in YbAl3, and quadrupling the best 2D power factor, 2.5 W⋅m(-1)⋅K(-1), in MoS2 We further show that the Seebeck coefficient provides a direct measure of substrate-induced random potential fluctuations and that their significant reduction for hBN substrates enables fast gate-controlled switching of the Seebeck coefficient polarity for applications in integrated active cooling devices.

  4. High thermoelectricpower factor in graphene/hBN devices

    NASA Astrophysics Data System (ADS)

    Duan, Junxi; Wang, Xiaoming; Lai, Xinyuan; Li, Guohong; Watanabe, Kenji; Taniguchi, Takashi; Zebarjadi, Mona; Andrei, Eva Y.

    2016-12-01

    Fast and controllable cooling at nanoscales requires a combination of highly efficient passive cooling and active cooling. Although passive cooling in graphene-based devices is quite effective due to graphene’s extraordinary heat conduction, active cooling has not been considered feasible due to graphene’s low thermoelectric power factor. Here, we show that the thermoelectric performance of graphene can be significantly improved by using hexagonal boron nitride (hBN) substrates instead of SiO2. We find the room temperature efficiency of active cooling in the device, as gauged by the power factor times temperature, reaches values as high as 10.35 Wṡm‑1ṡK‑1, corresponding to more than doubling the highest reported room temperature bulk power factors, 5 Wṡm‑1ṡK‑1, in YbAl3, and quadrupling the best 2D power factor, 2.5 Wṡm‑1ṡK‑1, in MoS2. We further show that the Seebeck coefficient provides a direct measure of substrate-induced random potential fluctuations and that their significant reduction for hBN substrates enables fast gate-controlled switching of the Seebeck coefficient polarity for applications in integrated active cooling devices.

  5. Electron Cooling

    NASA Astrophysics Data System (ADS)

    Ellison, Timothy J. P.

    1991-08-01

    Electron cooling is a method of reducing the 6 -dimensional phase space volume of a stored ion beam. The technique was invented by Budker and first developed by him and his colleagues at the Institute for Nuclear Physics in Novosibirsk. Further studies of electron cooling were subsequently performed at CERN and Fermilab. At the Indiana University Cyclotron Facility (IUCF) an electron cooling system was designed, built, and commissioned in 1988. This was the highest energy system built to date (270 keV for cooling 500 MeV protons) and the first such system to be used as an instrument for performing nuclear and atomic physics experiments. This dissertation summarizes the design principles; measurements of the longitudinal drag rate (cooling force), equilibrium cooled beam properties and effective longitudinal electron beam temperature. These measurements are compared with theory and with the measured performance of other cooling systems. In addition the feasibility of extending this technology to energies an order of magnitude higher are discussed.

  6. A passive-flow microfluidic device for imaging latent HIV activation dynamics in single T cells

    PubMed Central

    Gearhart, Larisa M.; Miller-Jensen, Kathryn

    2015-01-01

    Quantifying cell-to-cell variability in drug response dynamics is important when evaluating therapeutic efficacy. For example, optimizing latency reversing agents (LRAs) for use in a clinical “activate-and-kill” strategy to purge the latent HIV reservoir in patients requires minimizing heterogeneous viral activation dynamics. To evaluate how heterogeneity in latent HIV activation varies across a range of LRAs, we tracked drug-induced response dynamics in single cells via live-cell imaging using a latent HIV–GFP reporter virus in a clonal Jurkat T cell line. To enable these studies in suspension cells, we designed a simple method to capture an array of single Jurkat T cells using a passive-flow microfluidic device. Our device, which does not require external pumps or tubing, can trap hundreds of cells within minutes with a high retention rate over 12 hours of imaging. Using this device, we quantified heterogeneity in viral activation stimulated by transcription factor (TF) activators and histone deacetylase (HDAC) inhibitors. Generally, TF activators resulted in both faster onset of viral activation and faster rates of production, while HDAC inhibitors resulted in more uniform onset times, but more heterogeneous rates of production. Finally, we demonstrated that while onset time of viral gene expression and rate of viral production together predict total HIV activation, rate and onset time were not correlated within the same individual cell, suggesting that these features are regulated independently. Overall, our results reveal drug-specific patterns of noisy HIV activation dynamics not previously identified in static single-cell assays, which may require consideration for the most effective activate-and-kill regime. PMID:26138068

  7. A passive-flow microfluidic device for imaging latent HIV activation dynamics in single T cells.

    PubMed

    Ramji, Ramesh; Wong, Victor C; Chavali, Arvind K; Gearhart, Larisa M; Miller-Jensen, Kathryn

    2015-09-01

    Quantifying cell-to-cell variability in drug response dynamics is important when evaluating therapeutic efficacy. For example, optimizing latency reversing agents (LRAs) for use in a clinical "activate-and-kill" strategy to purge the latent HIV reservoir in patients requires minimizing heterogeneous viral activation dynamics. To evaluate how heterogeneity in latent HIV activation varies across a range of LRAs, we tracked drug-induced response dynamics in single cells via live-cell imaging using a latent HIV-GFP reporter virus in a clonal Jurkat T cell line. To enable these studies in suspension cells, we designed a simple method to capture an array of single Jurkat T cells using a passive-flow microfluidic device. Our device, which does not require external pumps or tubing, can trap hundreds of cells within minutes with a high retention rate over 12 hours of imaging. Using this device, we quantified heterogeneity in viral activation stimulated by transcription factor (TF) activators and histone deacetylase (HDAC) inhibitors. Generally, TF activators resulted in both faster onset of viral activation and faster rates of production, while HDAC inhibitors resulted in more uniform onset times, but more heterogeneous rates of production. Finally, we demonstrated that while onset time of viral gene expression and rate of viral production together predict total HIV activation, rate and onset time were not correlated within the same individual cell, suggesting that these features are regulated independently. Overall, our results reveal drug-specific patterns of noisy HIV activation dynamics not previously identified in static single-cell assays, which may require consideration for the most effective activate-and-kill regime.

  8. Coherent electron cooling demonstration experiment

    SciTech Connect

    Litvinenko, V.N.; Belomestnykh, S.; Ben-Zvi, I.; Brutus, J.C.; Fedotov, A.; Hao, Y.; Kayran, D.; Mahler, G.; Marusic, A.; Meng, W.; McIntyre, G.; Minty, M.; Ptitsyn, V.; Pinayev, I.; Rao, T.; Roser, T.; Sheehy, B.; Tepikian, S.; Than, R.; Trbojevic, D.; Tuozzolo, J.; Wang, G.; Yakimenko, V.; Hutton, A.; Krafft, G.; Poelker, M.; Rimmer, R.; Bruhwiler, D.; Abell, D.T.; Nieter, C.; Ranjbar, V.; Schwartz, B.; Kholopov M.; Shevchenko, O.; McIntosh, P.; Wheelhouse, A.

    2011-09-04

    Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.

  9. Physical Modeling of Activation Energy in Organic Semiconductor Devices based on Energy and Momentum Conservations.

    PubMed

    Mao, Ling-Feng; Ning, H; Hu, Changjun; Lu, Zhaolin; Wang, Gaofeng

    2016-04-22

    Field effect mobility in an organic device is determined by the activation energy. A new physical model of the activation energy is proposed by virtue of the energy and momentum conservation equations. The dependencies of the activation energy on the gate voltage and the drain voltage, which were observed in the experiments in the previous independent literature, can be well explained using the proposed model. Moreover, the expression in the proposed model, which has clear physical meanings in all parameters, can have the same mathematical form as the well-known Meyer-Neldel relation, which lacks of clear physical meanings in some of its parameters since it is a phenomenological model. Thus it not only describes a physical mechanism but also offers a possibility to design the next generation of high-performance optoelectronics and integrated flexible circuits by optimizing device physical parameter.

  10. Physical Modeling of Activation Energy in Organic Semiconductor Devices based on Energy and Momentum Conservations

    PubMed Central

    Mao, Ling-Feng; Ning, H.; Hu, Changjun; Lu, Zhaolin; Wang, Gaofeng

    2016-01-01

    Field effect mobility in an organic device is determined by the activation energy. A new physical model of the activation energy is proposed by virtue of the energy and momentum conservation equations. The dependencies of the activation energy on the gate voltage and the drain voltage, which were observed in the experiments in the previous independent literature, can be well explained using the proposed model. Moreover, the expression in the proposed model, which has clear physical meanings in all parameters, can have the same mathematical form as the well-known Meyer-Neldel relation, which lacks of clear physical meanings in some of its parameters since it is a phenomenological model. Thus it not only describes a physical mechanism but also offers a possibility to design the next generation of high-performance optoelectronics and integrated flexible circuits by optimizing device physical parameter. PMID:27103586

  11. Physical Modeling of Activation Energy in Organic Semiconductor Devices based on Energy and Momentum Conservations

    NASA Astrophysics Data System (ADS)

    Mao, Ling-Feng; Ning, H.; Hu, Changjun; Lu, Zhaolin; Wang, Gaofeng

    2016-04-01

    Field effect mobility in an organic device is determined by the activation energy. A new physical model of the activation energy is proposed by virtue of the energy and momentum conservation equations. The dependencies of the activation energy on the gate voltage and the drain voltage, which were observed in the experiments in the previous independent literature, can be well explained using the proposed model. Moreover, the expression in the proposed model, which has clear physical meanings in all parameters, can have the same mathematical form as the well-known Meyer-Neldel relation, which lacks of clear physical meanings in some of its parameters since it is a phenomenological model. Thus it not only describes a physical mechanism but also offers a possibility to design the next generation of high-performance optoelectronics and integrated flexible circuits by optimizing device physical parameter.

  12. Laboratory demonstration model: Active cleaning technique device. [for removal of contaminants from an optical surface

    NASA Technical Reports Server (NTRS)

    Shannon, R. L.; Gillette, R. B.

    1974-01-01

    The technique which utilizes exposure to a plasma to remove contaminants from a surface was incorporated into a laboratory model which demonstrates active cleaning by both plasma cleaning and ion sputtering modes of operation. The development phase is reported and includes discussion of the plasma tube configuration, device design, and performance tests. A general description of the active cleaning device is provided which includes information on the main power/plasma discharge sensors, and the power, gas supply, and ion accelerator systems. Development of the active cleaning species at high vacuum conditions is described and results indicate that plasma cleaning occurs in the region of a visible plume which extends from the end of the plasma tube. Recommendations are made for research to determine the plasma cleaning mechanism and the plasma species responsible for the cleaning, as well limitations on the type of contaminants that can be removed.

  13. A Novel Wearable Device for Food Intake and Physical Activity Recognition

    PubMed Central

    Farooq, Muhammad; Sazonov, Edward

    2016-01-01

    Presence of speech and motion artifacts has been shown to impact the performance of wearable sensor systems used for automatic detection of food intake. This work presents a novel wearable device which can detect food intake even when the user is physically active and/or talking. The device consists of a piezoelectric strain sensor placed on the temporalis muscle, an accelerometer, and a data acquisition module connected to the temple of eyeglasses. Data from 10 participants was collected while they performed activities including quiet sitting, talking, eating while sitting, eating while walking, and walking. Piezoelectric strain sensor and accelerometer signals were divided into non-overlapping epochs of 3 s; four features were computed for each signal. To differentiate between eating and not eating, as well as between sedentary postures and physical activity, two multiclass classification approaches are presented. The first approach used a single classifier with sensor fusion and the second approach used two-stage classification. The best results were achieved when two separate linear support vector machine (SVM) classifiers were trained for food intake and activity detection, and their results were combined using a decision tree (two-stage classification) to determine the final class. This approach resulted in an average F1-score of 99.85% and area under the curve (AUC) of 0.99 for multiclass classification. With its ability to differentiate between food intake and activity level, this device may potentially be used for tracking both energy intake and energy expenditure. PMID:27409622

  14. Coronal temperatures of selected active cool stars as derived from low resolution Einstein observations

    NASA Technical Reports Server (NTRS)

    Vilhu, Osmi; Linsky, Jeffrey L.

    1990-01-01

    Mean coronal temperatures of some active G-K stars were derived from Rev1-processed Einstein-observatory's IPC-spectra. The combined X-ray and transition region emission line data are in rough agreement with static coronal loop models. Although the sample is too small to derive any statistically significant conclusions, it suggests that the mean coronal temperature depends linearly on the inverse Rossby-number, with saturation at short rotation periods.

  15. Aerothermal Performance of a Radiatively and Actively Cooled Panel at Mach 66

    DTIC Science & Technology

    1979-12-01

    Space Administration db~buuabU& Scie ~k ntUcn Tswh~ca Infamaltion Bran•h 1979 . .7 5 -, ’ WNW*" - --- sUrMMRY A flight-weight radiative and actively... ence 7. The panel holder has a sharp leading edge and a rectangular planform 141 cm (55.4 in.) wide by 300 cm (118 in.) long. The depth of the panel

  16. Semiconductor cooling by thin-film thermocouples

    NASA Technical Reports Server (NTRS)

    Tick, P. A.; Vilcans, J.

    1970-01-01

    Thin-film, metal alloy thermocouple junctions do not rectify, change circuit impedance only slightly, and require very little increase in space. Although they are less efficient cooling devices than semiconductor junctions, they may be applied to assist conventional cooling techniques for electronic devices.

  17. Cooled railplug

    DOEpatents

    Weldon, William F.

    1996-01-01

    The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers.

  18. Microfluidic Emulation of Mechanical Circulatory Support Device Shear-Mediated Platelet Activation

    PubMed Central

    Dimasi, A.; Rasponi, M.; Sheriff, J.; Chiu, W.-C.; Bluestein, D.; Tran, P.L.; Slepian, M. J.; Redaelli, A.

    2016-01-01

    Thrombosis of ventricular assist devices (VADs) compromises their performance, with associated risks of systemic embolization, stroke, pump stop and possible death. Anti-thrombotic (AT) drugs, utilized to limit thrombosis, are largely dosed empirically, with limited testing of their efficacy. Further, such testing, if performed, typically examines efficacy under static conditions, which is not reflective of actual shear-mediated flow. Here we adopted our previously developed Device Thrombogenicity Emulation methodology to design microfluidic platforms able to emulate representative shear stress profiles of mechanical circulatory support (MCS) devices. Our long-term goal is to utilize these systems for point-of-care (POC) personalized testing of AT efficacy under specific, individual shear profiles. First, we designed different types of microfluidic channels able to replicate sample shear stress patterns observed in MCS devices. Second, we explored the flexibility of microfluidic technology in generating dynamic shear stress profiles by modulating the geometrical features of the channels. Finally, we designed microfluidic channel systems able to emulate the shear stress profiles of two commercial VADs. From CFD analyses, the VAD-emulating microfluidic systems were able to replicate the main characteristics of the shear stress waveforms of the macroscale VADs (i.e. shear stress peaks and duration). Our results establish the basis for development of a lab-on-chip POC system able to perform device-specific and patient-specific platelet activation state assays. PMID:26578003

  19. Hydrothermal activity in Tertiary Icelandic crust: Implication for cooling processes along slow-spreading mid-ocean ridges

    NASA Astrophysics Data System (ADS)

    Pałgan, D.; Devey, C. W.; Yeo, I. A.

    2015-12-01

    Known hydrothermal activity along the Mid-Atlantic Ridge is mostly high-temperature venting, controlled by volcano-tectonic processes confined to ridge axes and neotectonic zones ~15km wide on each side of the axis (e.g. TAG or Snake Pit). However, extensive exploration and discoveries of new hydrothermal fields in off-axis regions (e.g. Lost City, MAR) show that hydrothermalism may, in some areas, be dominated by off-axis venting. Little is known about nature of such systems, including whether low-temperature "diffuse" venting dominates rather than high-temperature black-smokers. This is particularly interesting since such systems may transport up to 90% of the hydrothermal heat to the oceans. In this study we use Icelandic hot springs as onshore analogues for off-shore hydrothermal activity along the MAR to better understand volcano-tectonic controls on their occurrence, along with processes supporting fluid circulation. Iceland is a unique laboratory to study how new oceanic crust cools and suggests that old crust may not be as inactive as previously thought. Our results show that Tertiary (>3.3 Myr) crust of Iceland (Westfjords) has widespread low-temperature hydrothermal activity. Lack of tectonism (indicated by lack of seismicity), along with field research suggest that faults in Westfjords are no longer active and that once sealed, can no longer support hydrothermal circulation, i.e. none of the hot springs in the area occur along faults. Instead, dyke margins provide open and permeable fluid migration pathways. Furthermore, we suggest that the Reykjanes Ridge (south of Iceland) may be similar to Westfjords with hydrothermalism dominated by off-axis venting. Using bathymetric data we infer dyke positions and suggest potential sites for future exploration located away from neotectonic zone. We also emphasise the importance of biological observations in seeking for low-temperature hydrothermal activity, since chemical or optical methods are not sufficient.

  20. A shirt containing multistage phase change material and active cooling components was associated with increased exercise capacity in a hot, humid environment.

    PubMed

    McFarlin, Brian K; Henning, Andrea L; Venable, Adam S; Williams, Randall R; Best Sampson, Jill N

    2016-08-01

    Recent advances in clothing design include the incorporation of phase change materials (PCM) and other active cooling components (ACC) to provide better body heat dissipation. The purpose of this study was to determine the effect of wearing a shirt containing multistage PCM/ACC on exercise capacity at low (5.0), moderate-high (7.5) and extreme (9.0) levels of the physiological strain index (PSI). Fourteen individuals tested two shirts (control vs. cooling) during 45-min of interval running in a hot, humid (35 ± 1 °C; 55 ± 6% RH) environment. The cooling shirt resulted in an 8% improvement in exercise capacity at a PSI of 7.5 (p < 0.05). The observed increase in exercise capacity would likely translate to a significant improvement in exercise performance. More research is needed to determine a best practice approach for the use of cooling clothing as a counter to exercise-induced heat exposure. Practitioner Summary: In this report, we demonstrate that when forced to exercise in a hot, humid environment, an individual's exercise capacity may increase by as much as 8% when wearing a shirt composed of multistage phase change material and active cooling components.

  1. Semi-active control of helicopter vibration using controllable stiffness and damping devices

    NASA Astrophysics Data System (ADS)

    Anusonti-Inthra, Phuriwat

    Semi-active concepts for helicopter vibration reduction are developed and evaluated in this dissertation. Semi-active devices, controllable stiffness devices or controllable orifice dampers, are introduced; (i) in the blade root region (rotor-based concept) and (ii) between the rotor and the fuselage as semi-active isolators (in the non-rotating frame). Corresponding semi-active controllers for helicopter vibration reduction are also developed. The effectiveness of the rotor-based semi-active vibration reduction concept (using stiffness and damping variation) is demonstrated for a 4-bladed hingeless rotor helicopter in moderate- to high-speed forward flight. A sensitivity study shows that the stiffness variation of root element can reduce hub vibrations when proper amplitude and phase are used. Furthermore, the optimal semi-active control scheme can determine the combination of stiffness variations that produce significant vibration reduction in all components of vibratory hub loads simultaneously. It is demonstrated that desired cyclic variations in properties of the blade root region can be practically achieved using discrete controllable stiffness devices and controllable dampers, especially in the flap and lag directions. These discrete controllable devices can produce 35--50% reduction in a composite vibration index representing all components of vibratory hub loads. No detrimental increases are observed in the lower harmonics of blade loads and blade response (which contribute to the dynamic stresses) and controllable device internal loads, when the optimal stiffness and damping variations are introduced. The effectiveness of optimal stiffness and damping variations in reducing hub vibration is retained over a range of cruise speeds and for variations in fundamental rotor properties. The effectiveness of the semi-active isolator is demonstrated for a simplified single degree of freedom system representing the semi-active isolation system. The rotor

  2. An Investigation of the Largest Flares in Active Cool Star Binaries with ALEXIS

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1998-01-01

    After a long delay due to the initial problems with the ALEXIS attitude control, the heroic efforts on the part of the ALEXIS satellite team enabled us to carry out this survey. However, the combination of the higher than expected and variable background in the ALEXIS detectors, and the lower throughput of the ALEXIS telescopes resulted in no convincing detections of large flares from the active binary systems. In addition, vignetting-corrected effective exposure times from the ALEXIS aspect solution were not available prior to the end of this contract; therefore, we were unable to convert upper limits measured in ALEXIS counts to the equivalent.

  3. An Active Broad Area Cooling Model of a Cryogenic Propellant Tank with a Single Stage Reverse Turbo-Brayton Cycle Cryocooler

    NASA Technical Reports Server (NTRS)

    Guzik, Monica C.; Tomsik, Thomas M.

    2011-01-01

    As focus shifts towards long-duration space exploration missions, an increased interest in active thermal control of cryogenic propellants to achieve zero boil-off of cryogens has emerged. An active thermal control concept of considerable merit is the integration of a broad area cooling system for a cryogenic propellant tank with a combined cryocooler and circulator system that can be used to reduce or even eliminate liquid cryogen boil-off. One prospective cryocooler and circulator combination is the reverse turbo-Brayton cycle cryocooler. This system is unique in that it has the ability to both cool and circulate the coolant gas efficiently in the same loop as the broad area cooling lines, allowing for a single cooling gas loop, with the primary heat rejection occurring by way of a radiator and/or aftercooler. Currently few modeling tools exist that can size and characterize an integrated reverse turbo-Brayton cycle cryocooler in combination with a broad area cooling design. This paper addresses efforts to create such a tool to assist in gaining a broader understanding of these systems, and investigate their performance in potential space missions. The model uses conventional engineering and thermodynamic relationships to predict the preliminary design parameters, including input power requirements, pressure drops, flow rate, cycle performance, cooling lift, broad area cooler line sizing, and component operating temperatures and pressures given the cooling load operating temperature, heat rejection temperature, compressor inlet pressure, compressor rotational speed, and cryogenic tank geometry. In addition, the model allows for the preliminary design analysis of the broad area cooling tubing, to determine the effect of tube sizing on the reverse turbo-Brayton cycle system performance. At the time this paper was written, the model was verified to match existing theoretical documentation within a reasonable margin. While further experimental data is needed for full

  4. Methods, microfluidic devices, and systems for detection of an active enzymatic agent

    DOEpatents

    Sommer, Gregory J; Hatch, Anson V; Singh, Anup K; Wang, Ying-Chih

    2014-10-28

    Embodiments of the present invention provide methods, microfluidic devices, and systems for the detection of an active target agent in a fluid sample. A substrate molecule is used that contains a sequence which may cleave in the presence of an active target agent. A SNAP25 sequence is described, for example, that may be cleaved in the presence of Botulinum Neurotoxin. The substrate molecule includes a reporter moiety. The substrate molecule is exposed to the sample, and resulting reaction products separated using electrophoretic separation. The elution time of the reporter moiety may be utilized to identify the presence or absence of the active target agent.

  5. Safety Design Requirements for Active Hazard Mitigation Device (AHMD) Employed to Address Fast and Slow Cook-off Thermal Threats

    DTIC Science & Technology

    2014-12-18

    Hazard Mitigation Device (AHMD) Employed to Address Fast and Slow Cook-off Thermal Threats 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...environments. 15. SUBJECT TERMS Active Hazard Mitigation Device insensitive munitions fast cook-off slow...DESIGN REQUIREMENTS FOR ACTIVE HAZARD MITIGATION DEVICE (AHMD) EMPLOYED TO ADDRESS FAST AND SLOW COOK-OFF THERMAL THREATS DOD Fuze Engineering

  6. Dry etching techniques for active devices based on hexagonal boron nitride epilayers

    SciTech Connect

    Grenadier, Samuel; Li, Jing; Lin, Jingyu; Jiang, Hongxing

    2013-11-15

    Hexagonal boron nitride (hBN) has emerged as a fundamentally and technologically important material system owing to its unique physical properties including layered structure, wide energy bandgap, large optical absorption, and neutron capture cross section. As for any materials under development, it is necessary to establish device processing techniques to realize active devices based on hBN. The authors report on the advancements in dry etching techniques for active devices based on hBN epilayers via inductively coupled plasma (ICP). The effect of ICP radio frequency (RF) power on the etch rate and vertical side wall profile was studied. The etching depth and angle with respect to the surface were measured using atomic force microscopy showing that an etching rate ∼1.25 μm/min and etching angles >80° were obtained. Profilometer data and scanning electron microscope images confirmed these results. This work demonstrates that SF{sub 6} is very suitable for etching hBN epilayers in RF plasma environments and can serve as a guide for future hBN device processing.

  7. Photovoltaic performance of block copolymer devices is independent of the crystalline texture in the active layer

    DOE PAGES

    Guo, Changhe; Lee, Youngmin; Lin, Yen -Hao; ...

    2016-06-15

    The electronic properties of organic semiconductors are strongly influenced by intermolecular packing. When cast as thin films, crystalline π-conjugated molecules are strongly textured, potentially leading to anisotropic charge transport. Consequently, it is hypothesized that the orientation of crystallites in the active layer plays an important role in charge extraction and organic photovoltaic device performance. Here we demonstrate orientation control of molecular packing from mostly face-on to edge-on configurations in the active layer of P3HT-b-PFTBT block copolymer photovoltaics using 1-chloronaphthalene as a solvent additive. The effect of molecular orientations in P3HT crystals on charge transport and solar cell performance is examined.more » We find that optimized photovoltaic device performance is independent of the crystalline texture of P3HT. Our observations provide further insights into the molecular organization required for efficient charge transport and overall device efficiencies. That is, the dominant crystal orientation, whether face-on or edge-on, is not critical to organic solar cells. Furthermore, a broad distribution of crystallite orientations ensures pathways for charge transport in any direction and enables efficient charge extraction in photovoltaic devices.« less

  8. Photovoltaic performance of block copolymer devices is independent of the crystalline texture in the active layer

    SciTech Connect

    Guo, Changhe; Lee, Youngmin; Lin, Yen -Hao; Strzalka, Joseph; Wang, Cheng; Hexemer, Alexander; Jaye, Cherno; Fischer, Daniel A.; Verduzco, Rafael; Wang, Qing; Gomez, Enrique D.

    2016-06-15

    The electronic properties of organic semiconductors are strongly influenced by intermolecular packing. When cast as thin films, crystalline π-conjugated molecules are strongly textured, potentially leading to anisotropic charge transport. Consequently, it is hypothesized that the orientation of crystallites in the active layer plays an important role in charge extraction and organic photovoltaic device performance. Here we demonstrate orientation control of molecular packing from mostly face-on to edge-on configurations in the active layer of P3HT-b-PFTBT block copolymer photovoltaics using 1-chloronaphthalene as a solvent additive. The effect of molecular orientations in P3HT crystals on charge transport and solar cell performance is examined. We find that optimized photovoltaic device performance is independent of the crystalline texture of P3HT. Our observations provide further insights into the molecular organization required for efficient charge transport and overall device efficiencies. That is, the dominant crystal orientation, whether face-on or edge-on, is not critical to organic solar cells. Furthermore, a broad distribution of crystallite orientations ensures pathways for charge transport in any direction and enables efficient charge extraction in photovoltaic devices.

  9. Cool School.

    ERIC Educational Resources Information Center

    Stephens, Suzanne

    1980-01-01

    The design for Floyd Elementary School in Miami (Florida) seeks to harness solar energy to provide at least 70 percent of the annual energy for cooling needs and 90 percent for hot water. (Author/MLF)

  10. Cool Vest

    NASA Technical Reports Server (NTRS)

    1982-01-01

    ILC, Dover Division's lightweight cooling garment, called Cool Vest was designed to eliminate the harmful effects of heat stress; increases tolerance time in hot environments by almost 300 percent. Made of urethane-coated nylon used in Apollo, it works to keep the body cool, circulating chilled water throughout the lining by means of a small battery-powered pump. A pocket houses the pump, battery and the coolant which can be ice or a frozen gel, a valve control allows temperature regulation. One version is self-contained and portable for unrestrained movement, another has an umbilical line attached to an external source of coolant, such as standard tap water, when extended mobility is not required. It is reported from customers that the Cool Vest pays for itself in increased productivity in very high temperatures.

  11. Focused-ion-beam post-processing technology for active devices

    NASA Astrophysics Data System (ADS)

    Tee, Chyng Wen; Lau, Fat Kit; Zhao, Xin; Penty, Richard; White, Ian

    2006-09-01

    Focused ion beam (FIB) etching technology is a highly efficient post-processing technique with the functionality to perform sputter etching and deposition of metals or insulators by means of a computer-generated mask. The high resolution and the ability to remove material directly from the sample in-situ make FIB etching the ideal candidate for device prototyping of novel micro-size photonic component design. Furthermore, the fact that arbitrary profile can be etched directly onto a sample without the need to prepare conventional mask and photolithography process makes novel device research with rapid feedback from characterisation to design activities possible. In this paper, we present a concise summary of the research work in Cambridge based on FIB technology. We demonstrate the applicability of focussed ion beam post processing technology to active photonic devices research. Applications include the integration of advanced waveguide architectures onto active photonic components. We documents details on the integration of lens structure on tapered lasers, photonic crystals on active SOA-integrated waveguides and surface profiling of low-cost gain-guided vertical-cavity surface-emitting lasers. Furthermore, we discuss additional functions of FIB in the measurement of buried waveguide structures or the integration of total-internal-reflection (TIR) mirror in optical interconnect structures.

  12. Program plan for reliability and maintainability in active solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    1980-10-01

    Specific objectives are as follows: provide all groups that have solar R & M concerns with the information that is available to the program and that can assist in alleviating those concerns; assist the solar energy industry in improving levels of R & M performance in state of the art solar energy systems, components, and materials; assist in the early development of a viable infrastructure for the design, manufacture, installation, and maintenance of reliable, maintainable, and durable solar energy systems; assist in the development of appropriate standards, code provisions, and certification programs relating to the R & M performance of solar energy systems, components, and materials; and develop the information required to support the other activities within the R & M program. These objectives correspond to five areas of action: regulations, research and development, technology transfer, solar industry infrastructure development, and data collection and analysis.

  13. Registry-Based Prospective, Active Surveillance of Medical-Device Safety.

    PubMed

    Resnic, Frederic S; Majithia, Arjun; Marinac-Dabic, Danica; Robbins, Susan; Ssemaganda, Henry; Hewitt, Kathleen; Ponirakis, Angelo; Loyo-Berrios, Nilsa; Moussa, Issam; Drozda, Joseph; Normand, Sharon-Lise; Matheny, Michael E

    2017-02-09

    Background The process of assuring the safety of medical devices is constrained by reliance on voluntary reporting of adverse events. We evaluated a strategy of prospective, active surveillance of a national clinical registry to monitor the safety of an implantable vascular-closure device that had a suspected association with increased adverse events after percutaneous coronary intervention (PCI). Methods We used an integrated clinical-data surveillance system to conduct a prospective, propensity-matched analysis of the safety of the Mynx vascular-closure device, as compared with alternative approved vascular-closure devices, with data from the CathPCI Registry of the National Cardiovascular Data Registry. The primary outcome was any vascular complication, which was a composite of access-site bleeding, access-site hematoma, retroperitoneal bleeding, or any vascular complication requiring intervention. Secondary safety end points were access-site bleeding requiring treatment and postprocedural blood transfusion. Results We analyzed data from 73,124 patients who had received Mynx devices after PCI procedures with femoral access from January 1, 2011, to September 30, 2013. The Mynx device was associated with a significantly greater risk of any vascular complication than were alternative vascular-closure devices (absolute risk, 1.2% vs. 0.8%; relative risk, 1.59; 95% confidence interval [CI], 1.42 to 1.78; P<0.001); there was also a significantly greater risk of access-site bleeding (absolute risk, 0.4% vs. 0.3%; relative risk, 1.34; 95% CI, 1.10 to 1.62; P=0.001) and transfusion (absolute risk, 1.8% vs. 1.5%; relative risk, 1.23; 95% CI, 1.13 to 1.34; P<0.001). The initial alerts occurred within the first 12 months of monitoring. Relative risks were greater in three prespecified high-risk subgroups: patients with diabetes, those 70 years of age or older, and women. All safety alerts were confirmed in an independent sample of 48,992 patients from April 1, 2014, to

  14. Children with autistic spectrum disorders and speech-generating devices: communication in different activities at home.

    PubMed

    Thunberg, Gunilla; Ahlsén, Elisabeth; Sandberg, Annika Dahlgren

    2007-06-01

    The communication of four children with autistic spectrum disorder was investigated when they were supplied with a speech-generating device (SGD) in three different activities in their home environment: mealtime, story reading and "sharing experiences of the preschool day". An activity based communication analysis, in which collective and individual background factors for the activities were outlined, was used as a basis for the discussion of linguistic coding data derived from video-recordings made before and during SGD intervention. The coded communicative behaviours were engagement in activity, role in turn-taking, communicative form, function and effectiveness. An increase in communicative effectiveness was more noticeable when the SGDs could be used to fulfil goals and roles within the activity. The instruction to the parents to use the SGDs in their communication with the child had an important influence on the activities.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. Laser Cooling of Solids

    DTIC Science & Technology

    2009-01-01

    state coolers such as thermoelectric (Peltier) devices. Several studies have shown that ytterbium- or thulium -doped solids should be capable of providing...that there is an advantage of pumping with lower energy photons. This increased effi- ciency was part of the motivation for investigating thulium ...the quantum efficiency. For pure thulium -doped material, non-radiative decay can over- whelm anti-Stokes cooling, depending on the properties of the

  17. Large-Scale Coronal Heating from "Cool" Activity in the Solar Magnetic Network

    NASA Technical Reports Server (NTRS)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Hathaway, D. H.

    1999-01-01

    In Fe XII images from SOHO/EIT, the quiet solar corona shows structure on scales ranging from sub-supergranular (i.e., bright points and coronal network) to multi-supergranular (large-scale corona). In Falconer et al 1998 (Ap.J., 501, 386) we suppressed the large-scale background and found that the network-scale features are predominantly rooted in the magnetic network lanes at the boundaries of the supergranules. Taken together, the coronal network emission and bright point emission are only about 5% of the entire quiet solar coronal Fe XII emission. Here we investigate the relationship between the large-scale corona and the network as seen in three different EIT filters (He II, Fe IX-X, and Fe XII). Using the median-brightness contour, we divide the large-scale Fe XII corona into dim and bright halves, and find that the bright-half/dim half brightness ratio is about 1.5. We also find that the bright half relative to the dim half has 10 times greater total bright point Fe XII emission, 3 times greater Fe XII network emission, 2 times greater Fe IX-X network emission, 1.3 times greater He II network emission, and has 1.5 times more magnetic flux. Also, the cooler network (He II) radiates an order of magnitude more energy than the hotter coronal network (Fe IX-X, and Fe XII). From these results we infer that: 1) The heating of the network and the heating of the large-scale corona each increase roughly linearly with the underlying magnetic flux. 2) The production of network coronal bright points and heating of the coronal network each increase nonlinearly with the magnetic flux. 3) The heating of the large-scale corona is driven by widespread cooler network activity rather than by the exceptional network activity that produces the network coronal bright points and the coronal network. 4) The large-scale corona is heated by a nonthermal process since the driver of its heating is cooler than it is. This work was funded by the Solar Physics Branch of NASA's office of

  18. Effects of portable computing devices on posture, muscle activation levels and efficiency.

    PubMed

    Werth, Abigail; Babski-Reeves, Kari

    2014-11-01

    Very little research exists on ergonomic exposures when using portable computing devices. This study quantified muscle activity (forearm and neck), posture (wrist, forearm and neck), and performance (gross typing speed and error rates) differences across three portable computing devices (laptop, netbook, and slate computer) and two work settings (desk and computer) during data entry tasks. Twelve participants completed test sessions on a single computer using a test-rest-test protocol (30min of work at one work setting, 15min of rest, 30min of work at the other work setting). The slate computer resulted in significantly more non-neutral wrist, elbow and neck postures, particularly when working on the sofa. Performance on the slate computer was four times less than that of the other computers, though lower muscle activity levels were also found. Potential or injury or illness may be elevated when working on smaller, portable computers in non-traditional work settings.

  19. Device for controlling a safety valve disposed below an activation pump in a hydrocarbon production well

    SciTech Connect

    Lefebvre, H. M.; Helderle, P. M.

    1985-05-21

    In a hydrocarbon production well in which the effluent is activated by an activation pump installed in a production pipe, a safety valve is disposed in the production pipe below the pump, the safety valve being operated by lowering of an operating member by a controlling device. The controlling device comprises a piston and cylinder system, and connection means connecting the piston to the operating member during the downward movement of the piston. The cylinder and piston system is provided at the level of the pump, and is advantageously constituted by the production pipe and pump respectively, so that pressurized fluid present at the level of the pump will cause downward movement of the piston.

  20. An active drop counting device using condenser microphone for superheated emulsion detector

    SciTech Connect

    Das, Mala; Marick, C.; Kanjilal, D.; Saha, S.

    2008-11-15

    An active device for superheated emulsion detector is described. A capacitive diaphragm sensor or condenser microphone is used to convert the acoustic pulse of drop nucleation to electrical signal. An active peak detector is included in the circuit to avoid multiple triggering of the counter. The counts are finally recorded by a microprocessor based data acquisition system. Genuine triggers, missed by the sensor, were studied using a simulated clock pulse. The neutron energy spectrum of {sup 252}Cf fission neutron source was measured using the device with R114 as the sensitive liquid and compared with the calculated fission neutron energy spectrum of {sup 252}Cf. Frequency analysis of the detected signals was also carried out.

  1. A portable multi-channel wireless NIRS device for muscle activity real-time monitoring.

    PubMed

    Yao, Pengfei; Guo, Weichao; Sheng, Xinjun; Zhang, Dingguo; Zhu, Xiangyang

    2014-01-01

    Near-infrared spectroscopy (NIRS) is a relative new technology in monitoring muscle oxygenation and hemo-dynamics. This paper presents a portable multi-channel wireless NIRS device for real-time monitoring of muscle activity. The NIRS sensor is designed miniaturized and modularized, to make multi-site monitoring convenient. Wireless communication is applied to data transmission avoiding of cumbersome wires and the whole system is highly integrated. Special care is taken to eliminate motion artifact when designing the NIRS sensor and attaching it to human skin. Besides, the system is designed with high sampling rate so as to monitor rapid oxygenation changes during muscle activities. Dark noise and long-term drift tests have been carried out, and the result indicates the device has a good performance of accuracy and stability. In vivo experiments including arterial occlusion and isometric voluntary forearm muscle contraction were performed, demonstrating the system has the ability to monitor muscle oxygenation parameters effectively even in exercise.

  2. Persistent hydrocephalus due to postural activation of a ventricular shunt anti-gravity device.

    PubMed

    Craven, Claudia L; Toma, Ahmed K; Watkins, Laurence D

    2017-03-01

    The ever present need to balance over drainage with under drainage in hydrocephalus has required innovations including adjustable valves with antigravity devices. These are activated in the vertical position to prevent siphoning. We describe a group of bedridden patients who presented with unexplained under drainage caused by activation of antigravity shunt components produced by peculiar head/body position. Retrospective single centre case series of hydrocephalus patients, treated with ventriculo-peritoneal (VP) shunt insertion between April 2014 - February 2016. These patients presented with clinical and radiological under drainage syndrome. Medical notes were reviewed for clinical picture and outcome. Radiological studies were reviewed assessing shunt placement and ventricular size. Seven patients presented with clinical and radiological under drainage syndrome. A consistent posturing of long term hyper-flexion of the neck whilst lying supine was observed. All patients had similar shunt construct (adjustable Miethke ProGAV valve and shunt assistant anti-gravity component). In each of those patients a hypothesis was formulated that neck flexion was activating the shunt assistance anti-gravity component in supine position. Five patients underwent shunt revision surgery removing the shunt assistant device from the cranium and adding an anti-gravity component to the shunt system at the chest. One had the shunt assistant completely removed and one patient was managed conservatively with mobilisation. All patients had clinical and radiological improvement. Antigravity shunt components implanted cranially in bedridden hydrocephalus patients will produce underdrainage due to head flexion induced anti-gravity device activation. In these patients, anti-gravity devices should be placed at the chest. Alternatively, special nursing attention should be paid to head-trunk angle.

  3. The influence of intrinsic sympathomimetic activity and beta-1 receptor selectivity on the recovery of finger skin temperature after finger cooling in normotensive subjects.

    PubMed

    Lenders, J W; Salemans, J; de Boo, T; Lemmens, W A; Thien, T; van't Laar, A

    1986-03-01

    A double-blind randomized study was designed to investigate differences in the recovery of finger skin temperature after finger cooling during dosing with placebo or one of four beta-blockers: propranolol, atenolol, pindolol, and acebutolol. In 11 normotensive nonsmoking subjects, finger skin temperature was measured with a thermocouple before and 20 minutes after immersion of one hand in a water bath at 16 degrees C. This finger cooling test caused no significant changes in systemic hemodynamics such as arterial blood pressure, heart rate, and forearm blood flow. The recovery of finger skin temperature during propranolol dosing was better than that during pindolol and atenolol dosing. There were no differences between the recoveries of skin temperature during pindolol, atenolol, and acebutolol dosing. Thus we could demonstrate no favorable effect of intrinsic sympathomimetic activity or beta 1-selectivity on the recovery of finger skin temperature after finger cooling.

  4. Cooling-induced contraction of the rat gastric fundus: mediation via transient receptor potential (TRP) cation channel TRPM8 receptor and Rho-kinase activation.

    PubMed

    Mustafa, S; Oriowo, Ma

    2005-10-01

    1. Cooling has been shown to induce contractions of several smooth muscles in vitro. However, the mechanism involved in the response is not yet known. In the present study, we investigated the possible involvement of transient receptor potential (TRP) cation channel TRPM8 receptors and the Rho-kinase pathway in cooling-induced contraction of the rat fundus. 2. Cooling-induced contractions were inversely proportional to temperature. Contractions were significantly reduced (by 65.6 +/- 2.4%; P < 0.05) in a Ca2+-free (1 mmol/L EGTA) medium, but were not significantly inhibited by nifedipine (10(-6) mol/L). 3. Capsazepine (3 x 10(-6) and 3 x 10(-5) mol/L), a TRPM8 receptor antagonist, inhibited cooling-induced contraction of the rat gastric fundus. 4. The Rho-kinase inhibitor Y-27632 concentration-dependently inhibited cooling-induced contraction of the gastric fundus, producing approximately 90% inhibition at a concentration of 10(-5) mol/L. Contractions were also inhibited by genistein (3 x 10(-5) mol/L), a tyrosine kinase inhibitor, but not by GF 109203X (10(-7) mol/L), a protein kinase C inhibitor. 5. Using reverse transcription-polymerase chain reaction techniques, it was observed that the mRNA for the TRPM8 receptor and Rho-kinase were expressed in the rat gastric fundus. 6. These results would suggest that cooling-induced contraction of the rat fundus is mediated by activation of TRPM8 receptors via a mechanism involving activation of Rho-kinase.

  5. A high-resolution lake sediment record of glacier activity from SE Greenland defines abrupt Holocene cooling events

    NASA Astrophysics Data System (ADS)

    Balascio, N. L.; Bradley, R. S.; D'Andrea, W. J.

    2013-12-01

    Orbital driven changes in high latitude summer insolation during the Holocene are responsible for the primary millennial-scale climate trends in the Arctic. Following deglaciation, maximum summer temperatures generally occurred during the early to mid-Holocene and declined through the late Holocene. Superimposed on this gradual cooling trend are centennial- and decadal-scale intervals that indicate more rapid perturbations of the arctic climate system. Highly resolved sedimentary records from terrestrial and marine sites help to better characterize climate system dynamics during the Holocene and investigate forcing and feedback mechanism that operate on different timescales. Reconstructing glacial activity can provide valuable paleoclimate information about trends in summer temperature and/or winter precipitation. Proglacial lakes contain sediment archives of meltwater input from glaciers and typically have high sedimentation rates preserving detailed information on glacial activity. However, interpreting proglacial sedimentary records can be difficult because 1) there may be significant input of sediment from non-glacial sources, 2) there is often a lack of organic material for radiocarbon dating, and 3) not all glaciers are sensitive to rapid climatic changes. Here we present a c. 10 cal ka BP record of glacier activity from Kulusuk Lake (65.6°N, 37.1°W; 202 m a.s.l.), a proglacial lake in southeast Greenland that is well constrained by radiocarbon dates and shows a clear signal of changes in glacial input throughout the Holocene. Kulusuk Lake is presently fed by meltwater from two cirque glaciers. It has a small catchment and no other significant source of sediment input. A 3.5 m sediment core contains distinct lithologic changes defined by grain size, magnetic susceptibility, organic content, and scanning XRF data. During the early Holocene, an overall decrease in meltwater input from 8.7-7.7 ka indicates the retreat of the glaciers in response to regional

  6. Observation and interpretation of thermal instabilities at the front face of actively cooled limiters in TORE-SUPRA

    SciTech Connect

    Guilhem, D.; Hogan, J.T.; Mitteau, R.; Phillips, V.

    1995-12-01

    In TORE-SUPRA, actively cooled modular limiters (time constant = 2 s) covered with carbon have been used to exhaust the convective heat flux continuously up to 700 kW steady state (design value) without thermal instability, i.e., 4.5 MW/m{sup 2} on average. Steady state surface temperatures in the range 600 C (with 1.45 MW of Lower Hybrid waves) were routinely obtained. However, sudden surface temperature excursions from 600 C to 1,900 C, called ``super-brilliances``, were observed during ohmic or heated plasmas, taking place locally over 20 ms, which led to a new equilibrium. This new equilibrium correspond to a local increased power flux density to the limiter as confirmed by calorimetric measurements. Shot after shot, an increasing number of independent overheated zones (up to 4) were observed on the limiter ridge, the closest location to Last Closed Flux Surface (LCFS). The power extracted by the limiter then was {approximately} 1.1 MW (6.9 MW/m{sup 2} average and 15 MW/m{sup 2} maximum). Experimental data and possible mechanisms leading to a finite increased heat flux to the limiter surface are reviewed and comparisons with modelization are made.

  7. Design of multi-megawatt actively cooled beam dumps for the Neutral-Beam Engineering Test Facility

    SciTech Connect

    Paterson, J.A.; Koehler, G.; Wells, R.P.

    1981-10-01

    The Neutral Beam Engineering Test Facility will test Neutral Beam Sources up to 170 keV, 65 Amps, with 30 second beam-on times. For this application actively cooled beam dumps for both the neutral and ionized particles will be required. The dumps will be able to dissipate a wide range of power density profiles by utilizing a standard modular panel design which is incorporated into a moveable support structure. The thermal hydraulic design of the panels permit the dissipation of 2 kW/cm/sup 2/ anywhere on the panel surface. The water requirements of the dumps are optimized by restricting the flow to panel sections where the heat flux falls short of the design value. The mechanical design of the beam-dump structures is described along with tests performed on a prototype panel. The prototype tests were performed on two different panel designs, one manufactured by Mc Donnell Douglas (MDAC) the other by United Technologies (UT). The dissipation capabilities of the panels were tested at the critical regions to verify their use in the beam dump assemblies.

  8. Use of a Far-Infrared Active Warming Device in Guinea Pigs (Cavia porcellus).

    PubMed

    Zarndt, Bethany S; Buchta, Jessica N; Garver, Lindsey S; Davidson, Silas A; Rowton, Edgar D; Despain, Kenneth E

    2015-11-01

    Small mammals have difficulty maintaining body temperature under anesthesia. This hypothermia is a potential detriment not only to the health and comfort of the animal but also to the integrity of any treatment given or data gathered during the anesthetic period. Using an external warming device to assist with temperature regulation can mitigate these effects. In this study, we investigated the ability of an advanced warming device that uses far-infrared (FIR) heating and responds to real-time core temperature monitoring to maintain a normothermic core temperature in guinea pigs. Body temperatures were measured during 30 min of ketamine-xylazine general anesthesia with and without application of the heating device. The loss of core body heat from anesthetized guinea pigs under typical (unwarmed) conditions was significant, and this loss was almost completely mitigated by application of the FIR heating pad. The significant difference between the temperatures of the actively warmed guinea pigs as compared with the control group began as early as 14 min after anesthetic administration, leading to a 2.6 °C difference at 30 min. Loss of core body temperature was not correlated with animals' body weight; however, weight influences the efficiency of FIR warming slightly. These study results show that the FIR heating device accurately controls core body temperature in guinea pigs, therefore potentially alleviating the effects of body heat loss on animal physiology.

  9. Active Deformation in the Greater Himalayan Zone in Western Nepal from Inversion of New (U-Th)/He Cooling Ages

    NASA Astrophysics Data System (ADS)

    Harvey, J. E.; Burbank, D.

    2015-12-01

    Much of the central Himalaya features an abrupt rise in mean elevation from ~1.5 km in the Lesser Himalaya to ~4-5 km Greater Himalaya and Tibetan Plateau. This physiographic transition is known as PT2, and is often interpreted as the surface expression of transport over a ramp in the Main Himalayan Thrust (MHT). In western Nepal, however, the same rise in elevation occurs over two distinct topographic steps (PT2-N and PT2-S). In previous work, Harvey et al. (2015) argue that this anomalous topography is the result of recent southward-migration of mid-crustal deformation along the MHT. Due to the seismogenic potential of the MHT it is important to constrain its geometry in the western Nepal seismic gap, which has not had a large earthquake in over 600 years. To test the above hypothesis, we perform [U-Th]/He dating on 39 apatite and 47 zircon samples collected along seven relief transects throughout western Nepal. We constrain exhumation histories by inverting these new cooling ages with the 3-D thermo-kinematic model Pecube. Five transects collected from the Greater Himalaya north of PT2-N are best fit by relatively rapid exhumation rates (~1-2 km/Myr) since ~4 Ma. The other two, collected from farther south near PT2-S, require rapid (~1-2 km/Myr) exhumation until around 8-11 Ma, followed by much slower (~0.1-0.2 km/Myr) exhumation until at least the late Pliocene. Assuming that exhumation rates reflect uplift rates, the rapid Plio-Pleistocene exhumation in the Greater Himalaya north of PT2-N suggest that this physiographic transition is similar to that at the foot of the Greater Himalaya in central Nepal. It follows that active deformation is occurring along a NW-trend as much as 100 km farther north than would be expected if simply projecting PT2 across western Nepal. This finding is consistent with transport over a more northerly MHT ramp or perhaps oblique slip along the recently identified, surface-breaking WNFZ. Although the geomorphology and microseismicity

  10. Mini-Membrane Evaporator for Contingency Spacesuit Cooling

    NASA Technical Reports Server (NTRS)

    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.

  11. Mini-Membrane Evaporator for Contingency Spacesuit Cooling

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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 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.

  12. Isolating plasma from blood using a dielectrophoresis-active hydrophoretic device.

    PubMed

    Yan, Sheng; Zhang, Jun; Alici, Gursel; Du, Haiping; Zhu, Yonggang; Li, Weihua

    2014-08-21

    Plasma is a complex substance that contains proteins and circulating nucleic acids and viruses that can be utilised for clinical diagnostics, albeit a precise analysis depends on the plasma being totally free of cells. We proposed the use of a dielectrophoresis (DEP)-active hydrophoretic method to isolate plasma from blood in a high-throughput manner. This microfluidic device consists of anisotropic microstructures embedded on the top of the channel which generate lateral pressure gradients while interdigitised electrodes lay on the bottom of the channel which can push particles or cells into a higher level using a negative DEP force. Large and small particles or cells (3 μm and 10 μm particles, and red blood cells, white blood cells, and platelets) can be focused at the same time in our DEP-active hydrophoretic device at an appropriate flow rate and applied voltage. Based on this principle, all the blood cells were filtrated from whole blood and then the plasma was extracted with a purity of 94.2% and a yield of 16.5% at a flow rate of 10 μL min(-1). This solved the challenging problem caused by the relatively low throughput of the DEP based device. Our DEP-active hydrophoretic device is a flexible and tunable system that can control the lateral positions of particles by modulating the external voltages without redesigning and fabricating a new channel, and because it is easy to operate, it is easily compatible with other microfluidic platforms that are used for further detection.

  13. Ionic Liquid Activation of Amorphous Metal-Oxide Semiconductors for Flexible Transparent Electronic Devices

    DOE PAGES

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony T.; ...

    2016-02-09

    To begin this abstract, amorphous metal-oxide semiconductors offer the high carrier mobilities and excellent large-area uniformity required for high performance, transparent, flexible electronic devices; however, a critical bottleneck to their widespread implementation is the need to activate these materials at high temperatures which are not compatible with flexible polymer substrates. The highly controllable activation of amorphous indium gallium zinc oxide semiconductor channels using ionic liquid gating at room temperature is reported. Activation is controlled by electric field-induced oxygen migration across the ionic liquid-semiconductor interface. In addition to activation of unannealed devices, it is shown that threshold voltages of a transistormore » can be linearly tuned between the enhancement and depletion modes. Finally, the first ever example of transparent flexible thin film metal oxide transistor on a polyamide substrate created using this simple technique is demonstrated. Finally, this study demonstrates the potential of field-induced activation as a promising alternative to traditional postdeposition thermal annealing which opens the door to wide scale implementation into flexible electronic applications.« less

  14. Ionic Liquid Activation of Amorphous Metal-Oxide Semiconductors for Flexible Transparent Electronic Devices

    SciTech Connect

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony T.; Ovchinnikova, Olga S.; Haglund, Amanda V.; Dai, Sheng; Ward, Thomas Zac; Mandrus, David; Rack, Philip D.

    2016-02-09

    To begin this abstract, amorphous metal-oxide semiconductors offer the high carrier mobilities and excellent large-area uniformity required for high performance, transparent, flexible electronic devices; however, a critical bottleneck to their widespread implementation is the need to activate these materials at high temperatures which are not compatible with flexible polymer substrates. The highly controllable activation of amorphous indium gallium zinc oxide semiconductor channels using ionic liquid gating at room temperature is reported. Activation is controlled by electric field-induced oxygen migration across the ionic liquid-semiconductor interface. In addition to activation of unannealed devices, it is shown that threshold voltages of a transistor can be linearly tuned between the enhancement and depletion modes. Finally, the first ever example of transparent flexible thin film metal oxide transistor on a polyamide substrate created using this simple technique is demonstrated. Finally, this study demonstrates the potential of field-induced activation as a promising alternative to traditional postdeposition thermal annealing which opens the door to wide scale implementation into flexible electronic applications.

  15. The Impact of Wearable Device Enabled Health Initiative on Physical Activity and Sleep

    PubMed Central

    Crowley, Olga; Kachnowski, Stan

    2016-01-01

    Objectives The Personal Health Management Study (PHMS) is an assessment of the effect of a voluntary employee-facing health initiative using a commercially-available wearable device implemented among 565 employees of Boehringer Ingelheim Pharmaceuticals, Inc. The results of the initiative on physical activity (measured as steps) and sleep is reported. Methods This was a 12-month, prospective, single-cohort intervention study using a wearable activity-measuring device tracking steps and sleep (entire study period) and a system of health-promoting incentives (first nine months of study period). The findings from the first nine study months are reported. Results The mixed model repeated measures approach was used to analyze the data. There was no significant difference in steps between the first month (7915.6 mean steps per person per day) and the last month (7853.4 mean steps per person per day) of the intervention. However, there was a seasonal decline in steps during the intervention period from fall to winter, followed by an increase in steps from winter to spring. In contrast, sleep tended to increase steadily throughout the study period, and the number of hours slept during the last month (7.52 mean hours per person per day) of the intervention was significantly greater than the number of hours slept during the first month (7.16 mean hours per person per day). Conclusions The impact of the initiative on physical activity and sleep differed over the period of time studied. While physical activity did not change between the first and last month of the intervention, the number of hours slept per night increased significantly. Although seasonal changes and study-device habituation may explain the pattern of change in physical activity, further evaluation is required to clarify the reasons underlying the difference in the impact of the initiative on the dynamics of steps and sleep. PMID:27882272

  16. Cooled railplug

    DOEpatents

    Weldon, W.F.

    1996-05-07

    The railplug is a plasma ignitor capable of injecting a high energy plasma jet into a combustion chamber of an internal combustion engine or continuous combustion system. An improved railplug is provided which has dual coaxial chambers (either internal or external to the center electrode) that provide for forced convective cooling of the electrodes using the normal pressure changes occurring in an internal combustion engine. This convective cooling reduces the temperature of the hot spot associated with the plasma initiation point, particularly in coaxial railplug configurations, and extends the useful life of the railplug. The convective cooling technique may also be employed in a railplug having parallel dual rails using dual, coaxial chambers. 10 figs.

  17. An adaptive Hidden Markov model for activity recognition based on a wearable multi-sensor device.

    PubMed

    Li, Zhen; Wei, Zhiqiang; Yue, Yaofeng; Wang, Hao; Jia, Wenyan; Burke, Lora E; Baranowski, Thomas; Sun, Mingui

    2015-05-01

    Human activity recognition is important in the study of personal health, wellness and lifestyle. In order to acquire human activity information from the personal space, many wearable multi-sensor devices have been developed. In this paper, a novel technique for automatic activity recognition based on multi-sensor data is presented. In order to utilize these data efficiently and overcome the big data problem, an offline adaptive-Hidden Markov Model (HMM) is proposed. A sensor selection scheme is implemented based on an improved Viterbi algorithm. A new method is proposed that incorporates personal experience into the HMM model as a priori information. Experiments are conducted using a personal wearable computer eButton consisting of multiple sensors. Our comparative study with the standard HMM and other alternative methods in processing the eButton data have shown that our method is more robust and efficient, providing a useful tool to evaluate human activity and lifestyle.

  18. Field-induced activation of metal oxide semiconductor for low temperature flexible transparent electronic device applications

    NASA Astrophysics Data System (ADS)

    Pudasaini, Pushpa Raj; Noh, Joo Hyon; Wong, Anthony; Haglund, Amada; Ward, Thomas Zac; Mandrus, David; Rack, Philip

    Amorphous metal-oxide semiconductors have been extensively studied as an active channel material in thin film transistors due to their high carrier mobility, and excellent large-area uniformity. Here, we report the athermal activation of amorphous indium gallium zinc oxide semiconductor channels by an electric field-induced oxygen migration via gating through an ionic liquid. Using field-induced activation, a transparent flexible thin film transistor is demonstrated on a polyamide substrate with transistor characteristics having a current ON-OFF ratio exceeding 108, and saturation field effect mobility of 8.32 cm2/(V.s) without a post-deposition thermal treatment. This study demonstrates the potential of field-induced activation as an athermal alternative to traditional post-deposition thermal annealing for metal oxide electronic devices suitable for transparent and flexible polymer substrates. Materials Science and Technology Division, ORBL, Oak Ridge, TN 37831, USA.

  19. Quantum-mechanical theory of optomechanical Brillouin cooling

    SciTech Connect

    Tomes, Matthew; Bahl, Gaurav; Carmon, Tal; Marquardt, Florian

    2011-12-15

    We analyze how to exploit Brillouin scattering of light from sound for the purpose of cooling optomechanical devices and present a quantum-mechanical theory for Brillouin cooling. Our analysis shows that significant cooling ratios can be obtained with standard experimental parameters. A further improvement of cooling efficiency is possible by increasing the dissipation of the optical anti-Stokes resonance.

  20. Active 2D and carbon-based materials: physics and devices (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Sorger, Volker J.

    2016-09-01

    In nanophotonics we create material-systems, which are structured at length scales smaller than the wavelength of light. When light propagates inside such effective materials numerous novel physics phenomena emerge including thresholdless lasing, atto-joule per bit efficient modulators, and exciton-polariton effects. However, in order to make use of these opportunities, synergistic device designs have to be applied to include materials, electric and photonic constrains - all at the nanoscale. In this talk, I present our recent progress in exploring 2D and TCO materials for active optoelectronics. I highlight nanoscale device demonstrations including their physical operation principle and performance benchmarks. Details include epsilon-bear-zero tuning of thin-film ITO, Graphene electro-static gating via Pauli-blocking, plasmonic electro-optic modulation, and hetero-integrated III-V and carbon-based plasmon lasers on Silicon photonics.

  1. Safety of active implantable devices during MRI examinations: a finite element analysis of an implantable pump.

    PubMed

    Büchler, Philippe; Simon, Anne; Burger, Jürgen; Ginggen, Alec; Crivelli, Rocco; Tardy, Yanik; Luechinger, Roger; Olsen, Sigbjørn

    2007-04-01

    The goal of this study was to propose a general numerical analysis methodology to evaluate the magnetic resonance imaging (MRI)-safety of active implants. Numerical models based on the finite element (FE) technique were used to estimate if the normal operation of an active device was altered during MRI imaging. An active implanted pump was chosen to illustrate the method. A set of controlled experiments were proposed and performed to validate the numerical model. The calculated induced voltages in the important electronic components of the device showed dependence with the MRI field strength. For the MRI radiofrequency fields, significant induced voltages of up to 20 V were calculated for a 0.3T field-strength MRI. For the 1.5 and 3.0OT MRIs, the calculated voltages were insignificant. On the other hand, induced voltages up to 11 V were calculated in the critical electronic components for the 3.0T MRI due to the gradient fields. Values obtained in this work reflect to the worst case situation which is virtually impossible to achieve in normal scanning situations. Since the calculated voltages may be removed by appropriate protection circuits, no critical problems affecting the normal operation of the pump were identified. This study showed that the proposed methodology helps the identification of the possible incompatibilities between active implants and MR imaging, and can be used to aid the design of critical electronic systems to ensure MRI-safety.

  2. How Accurately Can Your Wrist Device Recognize Daily Activities and Detect Falls?

    PubMed Central

    Gjoreski, Martin; Gjoreski, Hristijan; Luštrek, Mitja; Gams, Matjaž

    2016-01-01

    Although wearable accelerometers can successfully recognize activities and detect falls, their adoption in real life is low because users do not want to wear additional devices. A possible solution is an accelerometer inside a wrist device/smartwatch. However, wrist placement might perform poorly in terms of accuracy due to frequent random movements of the hand. In this paper we perform a thorough, large-scale evaluation of methods for activity recognition and fall detection on four datasets. On the first two we showed that the left wrist performs better compared to the dominant right one, and also better compared to the elbow and the chest, but worse compared to the ankle, knee and belt. On the third (Opportunity) dataset, our method outperformed the related work, indicating that our feature-preprocessing creates better input data. And finally, on a real-life unlabeled dataset the recognized activities captured the subject’s daily rhythm and activities. Our fall-detection method detected all of the fast falls and minimized the false positives, achieving 85% accuracy on the first dataset. Because the other datasets did not contain fall events, only false positives were evaluated, resulting in 9 for the second, 1 for the third and 15 for the real-life dataset (57 days data). PMID:27258282

  3. How Accurately Can Your Wrist Device Recognize Daily Activities and Detect Falls?

    PubMed

    Gjoreski, Martin; Gjoreski, Hristijan; Luštrek, Mitja; Gams, Matjaž

    2016-06-01

    Although wearable accelerometers can successfully recognize activities and detect falls, their adoption in real life is low because users do not want to wear additional devices. A possible solution is an accelerometer inside a wrist device/smartwatch. However, wrist placement might perform poorly in terms of accuracy due to frequent random movements of the hand. In this paper we perform a thorough, large-scale evaluation of methods for activity recognition and fall detection on four datasets. On the first two we showed that the left wrist performs better compared to the dominant right one, and also better compared to the elbow and the chest, but worse compared to the ankle, knee and belt. On the third (Opportunity) dataset, our method outperformed the related work, indicating that our feature-preprocessing creates better input data. And finally, on a real-life unlabeled dataset the recognized activities captured the subject's daily rhythm and activities. Our fall-detection method detected all of the fast falls and minimized the false positives, achieving 85% accuracy on the first dataset. Because the other datasets did not contain fall events, only false positives were evaluated, resulting in 9 for the second, 1 for the third and 15 for the real-life dataset (57 days data).

  4. Personal cooling apparatus and method

    SciTech Connect

    Siman-Tov, Moshe; Crabtree, Jerry Allen

    2001-01-01

    A portable lightweight cooling apparatus for cooling a human body is disclosed, having a channeled sheet which absorbs sweat and/or evaporative liquid, a layer of highly conductive fibers adjacent the channeled sheet; and, an air-moving device for moving air through the channeled sheet, wherein the layer of fibers redistributes heat uniformly across the object being cooled, while the air moving within the channeled sheet evaporates sweat and/or other evaporative liquid, absorbs evaporated moisture and the uniformly distributed heat generated by the human body, and discharges them into the environment. Also disclosed is a method for removing heat generated by the human body, comprising the steps of providing a garment to be placed in thermal communication with the body; placing a layer of highly conductive fibers within the garment adjacent the body for uniformly distributing the heat generated by the body; attaching an air-moving device in communication with the garment for forcing air into the garment; removably positioning an exchangeable heat sink in communication with the air-moving device for cooling the air prior to the air entering the garment; and, equipping the garment with a channeled sheet in communication with the air-moving device so that air can be directed into the channeled sheet and adjacent the layer of fibers to expell heat and moisture from the body by the air being directed out of the channeled sheet and into the environment. The cooling system may be configured to operate in both sealed and unsealed garments.

  5. 76 FR 55394 - Agency Information Collection Activities; Proposed Collection; Comment Request; Medical Devices...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-07

    ... Collection; Comment Request; Medical Devices: Humanitarian Use Devices AGENCY: Food and Drug Administration... of information technology. Medical Devices: Humanitarian Use Devices--21 CFR Part 814 (OMB Control... to grant HUD designation of a medical device; (2) exempt an HUD from the effectiveness...

  6. Cooling vest

    NASA Technical Reports Server (NTRS)

    Kosmo, J.; Kane, J.; Coverdale, J.

    1977-01-01

    Inexpensive vest of heat-sealable urethane material, when strapped to person's body, presents significant uncomplicated cooling system for environments where heavy accumulation of metabolic heat exists. Garment is applicable to occupations where physical exertion is required under heavy protective clothing.

  7. Investigating the Efficacy of a Computerized Prompting Device to Assist Children with Autism Spectrum Disorder with Activities of Daily Living

    ERIC Educational Resources Information Center

    Bimbrahw, Justin; Boger, Jennifer; Mihailidis, Alex

    2012-01-01

    Learning to perform self-care skills can pose a major challenge for children with Autism Spectrum Disorder (ASD) as well as the parents and caregivers who support them. The computerized device described in this paper has been used by children with ASD and their carers to autonomously assist with self-care activities. The device uses computer…

  8. An Educational Device for a Hands-on Activity to Visualize the Effect of Atherosclerosis on Blood Flow

    ERIC Educational Resources Information Center

    de Almeida, J. P. P. G. L.; de Lima, J. L. M. P.

    2013-01-01

    An educational device was created to develop a hands-on activity to illustrate how atherosclerosis can dramatically reduce blood flow in human vessels. The device was conceived, designed, and built at the University of Coimbra, in response to a request from the Exploratorio Infante D. Henrique Science Centre Museum, where it is presently…

  9. An Exploration into How Physical Activity Data-Recording Devices Could Be Used in Computer-Supported Data Investigations

    ERIC Educational Resources Information Center

    Lee, Victor R.; DuMont, Maneksha

    2010-01-01

    There is a great potential opportunity to use portable physical activity monitoring devices as data collection tools for educational purposes. Using one such device, we designed and implemented a weeklong workshop with high school students to test the utility of such technology. During that intervention, students performed data investigations of…

  10. Keep Taking the Tablets? Assessing the Use of Tablet Devices in Learning and Teaching Activities in the Further Education Sector

    ERIC Educational Resources Information Center

    Fabian, Khristin; MacLean, Donald

    2014-01-01

    This article summarises the methodology and outcomes of an interventionist/action research project to assess the benefits, and potential pitfalls, of the use of mobile devices in learning and teaching activities in a Further Education environment. A bank of 15 tablet devices were purchased and prepared for classroom use. Staff members were…

  11. Single active-layer structured dual-function devices using hybrid polymer-quantum dots.

    PubMed

    Son, Dong-Ick; Park, Dong-Hee; Ie, Sang-Yub; Choi, Won-Kook; Choi, Ji-Won; Li, Fushan; Kim, Tae-Whan

    2008-10-01

    We demonstrate hybrid polymer-quantum dot dual-function devices with a single active-layer structure consisting of CdSe/ZnS semiconductor quantum dots dispersed with poly N-vinylcarbazole (PVK) and 1,3,5-tirs-(N-phenylbenzimidazol-2-yl) benzene (TPBi) fabricated on an indium-tin-oxide (ITO)/glass substrate by using a simple spin-coating technique. The dual-function devices are composed of light-emitting diodes (LED) on the top side and nonvolatile organic bistable memory devices (OBD) on the bottom side and can show electroluminescence (EL) along with electrical bistability concurrently. Both the functionality of LEDs and OBDs can be successfully achieved by adding an electron transport layer (ETL) TPBi to the OBD to attain an LED in which the lowest unoccupied molecular orbital (LUMO) level of TPBi is positioned at the energy level between the conduction band of CdSe/ZnS and the LiF/Al electrode. Through transmission electron microscopy (TEM) study, it is revealed that CdSe/ZnS QDs distributed on the interface of the hole transport layer (HTL) and ETL significantly take part in the electroluminescence process rather than those existing at the outer surface of the ETL.

  12. Fiber bragg grating sensor based device for simultaneous measurement of respiratory and cardiac activities.

    PubMed

    Chethana, K; Guru Prasad, A S; Omkar, S N; Asokan, S

    2017-02-01

    This paper reports a novel optical ballistocardiography technique, which is non-invasive, for the simultaneous measurement of cardiac and respiratory activities using a Fiber Bragg Grating Heart Beat Device (FBGHBD). The unique design of FBGHBD offers additional capabilities such as monitoring nascent morphology of cardiac and breathing activity, heart rate variability, heart beat rhythm, etc., which can assist in early clinical diagnosis of many conditions associated with heart and lung malfunctioning. The results obtained from the FBGHBD positioned around the pulmonic area on the chest have been evaluated against an electronic stethoscope which detects and records sound pulses originated from the cardiac activity. In order to evaluate the performance of the FBGHBD, quantitative and qualitative studies have been carried out and the results are found to be reliable and accurate, validating its potential as a standalone medical diagnostic device. The developed FBGHBD is simple in design, robust, portable, EMI proof, shock proof and non-electric in its operation which are desired features for any clinical diagnostic tool used in hospital environment.

  13. Laser fabrication of electrical feedthroughs in polymer encapsulations for active implantable medical devices.

    PubMed

    Gough, Zara; Chaminade, Cedric; Barclay-Monteith, Philip; Kallinen, Annukka; Lei, Wenwen; Ganesan, Rajesh; Grace, John; McKenzie, David R

    2017-01-31

    Hermetic electrical feedthroughs are essential for safe and functional active implantable biomedical devices and for a wide range of other applications such as batteries, supercapacitors, OLEDs and solar cells. Ceramics and metals have previously been the materials of choice for encapsulations, while polymers have advantages of ease of mass production and end user compatibility. We demonstrate a laser sealing technology that gives hermetic, mechanically strong feedthroughs with low electrical resistance in a polyetheretherketone (PEEK) encapsulation. The conductive pathways are wires and sputtered thin films. The water vapor transmission rate through the fabricated encapsulations is comparable to that of PEEK itself.

  14. Conceiving semi-active control devices for large-size monolithic monuments

    NASA Astrophysics Data System (ADS)

    Casciati, Fabio; El Attar, Adel; Casciati, Sara

    2001-07-01

    CHIME is a research project, funded by the European Union, which investigates the adoption of innovative structural control techniques in view of the seismic rehabilitation of the wide monumental cultural heritage in Mediterranean countries as Egypt, Tunisia and Cyprus. The structural control devices are mainly of the semi-active type. In this particular paper one reports the first results achieved within a case study. It considers an Egyptian large size monolithic monument. Alternative solutions for its seismic rehabilitation are eventually conceived and discussed.

  15. Use of a consumer market activity monitoring and feedback device improves exercise capacity and activity levels in COPD.

    PubMed

    Caulfield, Brian; Kaljo, Indira; Donnelly, Seamas

    2014-01-01

    COPD is associated with a gradual decline in physical activity, which itself contributes to a worsening of the underlying condition. Strategies that improve physical activity levels are critical to halt this cycle. Wearable sensor based activity monitoring and persuasive feedback might offer a potential solution. However it is not clear just how much intervention might be needed in this regard - i.e. whether programmes need to be tailored specifically for the target clinical population or whether more simple activity monitoring and feedback solutions, such as that offered in consumer market devices, might be sufficient. This research was carried out to investigate the impact of 4 weeks of using an off the shelf consumer market activity monitoring and feedback application on measures of physical activity, exercise capacity, and health related quality of life in a population of 10 Stage I and II COPD patients. Results demonstrate a significant and positive effect on exercise capacity (measured using a 6-minute walk test) and activity levels (measured in terms of average number of steps per hour) yet no impact on health related quality of life (St Georges Respiratory Disease Questionnaire).

  16. Evaluating the Safety Profile of Non-Active Implantable Medical Devices Compared with Medicines.

    PubMed

    Pane, Josep; Coloma, Preciosa M; Verhamme, Katia M C; Sturkenboom, Miriam C J M; Rebollo, Irene

    2017-01-01

    Recent safety issues involving non-active implantable medical devices (NAIMDs) have highlighted the need for better pre-market and post-market evaluation. Some stakeholders have argued that certain features of medicine safety evaluation should also be applied to medical devices. Our objectives were to compare the current processes and methodologies for the assessment of NAIMD safety profiles with those for medicines, identify potential gaps, and make recommendations for the adoption of new methodologies for the ongoing benefit-risk monitoring of these devices throughout their entire life cycle. A literature review served to examine the current tools for the safety evaluation of NAIMDs and those for medicines. We searched MEDLINE using these two categories. We supplemented this search with Google searches using the same key terms used in the MEDLINE search. Using a comparative approach, we summarized the new product design, development cycle (preclinical and clinical phases), and post-market phases for NAIMDs and drugs. We also evaluated and compared the respective processes to integrate and assess safety data during the life cycle of the products, including signal detection, signal management, and subsequent potential regulatory actions. The search identified a gap in NAIMD safety signal generation: no global program exists that collects and analyzes adverse events and product quality issues. Data sources in real-world settings, such as electronic health records, need to be effectively identified and explored as additional sources of safety information, particularly in some areas such as the EU and USA where there are plans to implement the unique device identifier (UDI). The UDI and other initiatives will enable more robust follow-up and assessment of long-term patient outcomes. The safety evaluation system for NAIMDs differs in many ways from those for drugs, but both systems face analogous challenges with respect to monitoring real-world usage. Certain features

  17. Assistive devices in activities of daily living used by persons with age-related macular degeneration: a population study of 85-year-olds living at home.

    PubMed

    Dahlin Ivanoff, S; Sonn, U

    2005-03-01

    The purpose of this study was to investigate the overall use of assistive devices among persons with age-related macular degeneration (ARMD) and how it is related to dependence in daily activities. This was a retrospective, descriptive, cross-sectional population study of 85-year-olds. The most common category of assistive devices was bathing devices followed by mobility devices. The overall use of assistive devices was 82%, and around 80% of the device users were independent in activities of daily living. They were multiple device users (57%) and used more mobility devices and personal assistance in mobility. In conclusion, the ARMD group comprises very frequent users of assistive devices and uses assistive devices to remain independent. This implies that health services should provide assistive devices at an early stage in the disablement process to avoid the development of dependence and should consider the likelihood of multiple health problems when assessing the needs of assistive devices among persons with ARMD.

  18. Detection of hormone active chemicals using genetically engineered yeast cells and microfluidic devices with interdigitated array electrodes.

    PubMed

    Ino, Kosuke; Kitagawa, Yusuke; Watanabe, Tsuyoshi; Shiku, Hitoshi; Koide, Masahiro; Itayama, Tomoaki; Yasukawa, Tomoyuki; Matsue, Tomokazu

    2009-10-01

    Endocrine disruptors that act like hormones in the endocrine system might have toxic effects. Therefore, it is important to develop a portable device that can detect hormone active chemicals in samples rapidly and easily. In this study, a microfluidic device was developed for the detection of hormone active chemicals using genetically engineered yeast cells. The yeast cells were used as biosensors since they were genetically engineered to respond to the presence of hormone active chemicals by synthesizing beta-galactosidase (beta-gal). For achieving further sensitivity, we incorporated interdigitated array (IDA) electrodes (width, 1.2 microm; gap, 0.8 microm) with 40 electrode fingers into the analytical chamber of the microfluidic device. The yeast cells precultured with a hormone active chemical, 17beta-estradiol (E2), were trapped from the main channel of the device to the analytical camber by electrophoresis. After trapping in the analytical chamber, we performed electrochemical detection of beta-gal induced in the yeast cells with the IDA electrodes. Actually, electrochemical detection was performed on p-aminophenol that was converted from p-aminophenyl-beta-D-galactopyranoside with beta-gal. The electrochemical signals from the yeast cells precultured with 17beta-estradiol were successfully detected with the device. Furthermore, the inhibitory effects of antagonists such as tamoxifen were also detected electrochemically by using the device. Thus, the present microfluidic device can be used for highly sensitive detection of hormone active chemicals.

  19. Physical Activity Measurement Device Agreement: Pedometer Steps/Minute and Physical Activity Time

    ERIC Educational Resources Information Center

    Scruggs, Philip W.; Mungen, Jonathan D.; Oh, Yoonsin

    2010-01-01

    The purpose of this study was to examine agreement between the Walk4Life DUO pedometer (W4L; Walk4Life, Plainfield, Illinois, USA) and two criterion instruments in the measurement of physical activity. Participants (N = 189, M = 16.74 years, SD = 0.99) in high school physical education concurrently wore the DUO (i.e., comparison instrument) and…

  20. Methods of beam cooling

    SciTech Connect

    Sessler, A.M.

    1996-02-01

    Diverse methods which are available for particle beam cooling are reviewed. They consist of some highly developed techniques such as radiation damping, electron cooling, stochastic cooling and the more recently developed, laser cooling. Methods which have been theoretically developed, but not yet achieved experimentally, are also reviewed. They consist of ionization cooling, laser cooling in three dimensions and stimulated radiation cooling.

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

    SciTech Connect

    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.

  2. Energy storage using phase-change materials for active solar heating and cooling: An evaluation of future research and development direction

    NASA Astrophysics Data System (ADS)

    Borkowski, R. J.; Stovall, T. K.; Kedl, R. J.; Tomlinson, J. J.

    1982-04-01

    The current state of the art and commercial potential of active solar heating and cooling systems for buildings, and the use of thermal energy storage with these systems are assessed. The need for advanced latent heat storage subsystems in these applications and priorities for their development are determined. Latent storage subsystems are advantageous in applications where their compactness may be exploited. It is suggested that subsystems could facilitate storage in retrofit applications in which storage would be physically impossible otherwise.

  3. A microfluidic device for evaluating the dynamics of the metabolism-dependent antioxidant activity of nutrients.

    PubMed

    Lee, Jungwoo; Choi, Jong-ryul; Ha, Sang Keun; Choi, Inwook; Lee, Seung Hwan; Kim, Donghyun; Choi, Nakwon; Sung, Jong Hwan

    2014-08-21

    Various food components are known for their health-promoting effects. However, their biochemical effects are generally evaluated in vitro, and their actual in vivo effect can vary significantly, depending on their metabolic profiles. To evaluate the effect of the liver metabolism on the antioxidant activity, we have developed a two-compartment microfluidic system that integrates the dynamics of liver metabolism and the subsequent antioxidant activity of food components. In the first compartment of the device, human liver enzyme fractions were immobilized inside a poly(ethylene glycol) diacrylate (PEGDA) hydrogel to mimic the liver metabolism. The radical scavenging activity was evaluated by the change of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) absorbance in the second compartment. Reaction engineering and fluid mechanics principles were used to develop a simplified analytical model and a more complex finite element model, which were used to design the chip and determine the optimal flow conditions. For real-time measurements of the reaction on a chip, we developed a custom-made photospectrometer system with an LED light source. The developed microfluidic system showed a linear and dose-dependent antioxidant activity in response to increasing concentration of flavonoid. We also compared the antioxidant activity of flavonoid after various liver metabolic reactions. This microfluidic system can serve as a novel in vitro platform for predicting the antioxidant activity of various food components in a more physiologically realistic manner, as well as for studying the mechanism of action of such food components.

  4. Cooling technique

    DOEpatents

    Salamon, Todd R; Vyas, Brijesh; Kota, Krishna; Simon, Elina

    2017-01-31

    An apparatus and a method are provided. Use is made of a wick structure configured to receive a liquid and generate vapor in when such wick structure is heated by heat transferred from heat sources to be cooled off. A vapor channel is provided configured to receive the vapor generated and direct said vapor away from the wick structure. In some embodiments, heat conductors are used to transfer the heat from the heat sources to the liquid in the wick structure.

  5. Therapeutic Devices for Epilepsy

    PubMed Central

    Fisher, Robert S.

    2011-01-01

    Therapeutic devices provide new options for treating drug-resistant epilepsy. These devices act by a variety of mechanisms to modulate neuronal activity. Only vagus nerve stimulation, which continues to develop new technology, is approved for use in the United States. Deep brain stimulation (DBS) of anterior thalamus for partial epilepsy recently was approved in Europe and several other countries. Responsive neurostimulation, which delivers stimuli to one or two seizure foci in response to a detected seizure, recently completed a successful multicenter trial. Several other trials of brain stimulation are in planning or underway. Transcutaneous magnetic stimulation (TMS) may provide a noninvasive method to stimulate cortex. Controlled studies of TMS split on efficacy, and may depend on whether a seizure focus is near a possible region for stimulation. Seizure detection devices in the form of “shake” detectors via portable accelerometers can provide notification of an ongoing tonic-clonic seizure, or peace of mind in the absence of notification. Prediction of seizures from various aspects of EEG is in early stages. Prediction appears to be possible in a subpopulation of people with refractory seizures and a clinical trial of an implantable prediction device is underway. Cooling of neocortex or hippocampus reversibly can attenuate epileptiform EEG activity and seizures, but engineering problems remain in its implementation. Optogenetics is a new technique that can control excitability of specific populations of neurons with light. Inhibition of epileptiform activity has been demonstrated in hippocampal slices, but use in humans will require more work. In general, devices provide useful palliation for otherwise uncontrollable seizures, but with a different risk profile than with most drugs. Optimizing the place of devices in therapy for epilepsy will require further development and clinical experience. PMID:22367987

  6. Lithographically patterned thin activated carbon films as a new technology platform for on-chip devices.

    PubMed

    Wei, Lu; Nitta, Naoki; Yushin, Gleb

    2013-08-27

    Continuous, smooth, visibly defect-free, lithographically patterned activated carbon films (ACFs) are prepared on the surface of silicon wafers. Depending on the synthesis conditions, porous ACFs can either remain attached to the initial substrate or be separated and transferred to another dense or porous substrate of interest. Tuning the activation conditions allows one to change the surface area and porosity of the produced carbon films. Here we utilize the developed thin ACF technology to produce prototypes of functional electrical double-layer capacitor devices. The synthesized thin carbon film electrodes demonstrated very high capacitance in excess of 510 F g(-1) (>390 F cm(-3)) at a slow cyclic voltammetry scan rate of 1 mV s(-1) and in excess of 325 F g(-1) (>250 F cm(-3)) in charge-discharge tests at an ultrahigh current density of 45,000 mA g(-1). Good stability was demonstrated after 10,000 galvanostatic charge-discharge cycles. The high values of the specific and volumetric capacitances of the selected ACF electrodes as well as the capacity retention at high current densities demonstrated great potential of the proposed technology for the fabrication of various on-chip devices, such as micro-electrochemical capacitors.

  7. New cosurface capacitive stimulators for the development of active osseointegrative implantable devices

    NASA Astrophysics Data System (ADS)

    Soares Dos Santos, Marco P.; Marote, Ana; Santos, T.; Torrão, João; Ramos, A.; Simões, José A. O.; da Cruz E Silva, Odete A. B.; Furlani, Edward P.; Vieira, Sandra I.; Ferreira, Jorge A. F.

    2016-07-01

    Non-drug strategies based on biophysical stimulation have been emphasized for the treatment and prevention of musculoskeletal conditions. However, to date, an effective stimulation system for intracorporeal therapies has not been proposed. This is particularly true for active intramedullary implants that aim to optimize osseointegration. The increasing demand for these implants, particularly for hip and knee replacements, has driven the design of innovative stimulation systems that are effective in bone-implant integration. In this paper, a new cosurface-based capacitive system concept is proposed for the design of implantable devices that deliver controllable and personalized electric field stimuli to target tissues. A prototype architecture of this system was constructed for in vitro tests, and its ability to deliver controllable stimuli was numerically analyzed. Successful results were obtained for osteoblastic proliferation and differentiation in the in vitro tests. This work provides, for the first time, a design of a stimulation system that can be embedded in active implantable devices for controllable bone-implant integration and regeneration. The proposed cosurface design holds potential for the implementation of novel and innovative personalized stimulatory therapies based on the delivery of electric fields to bone cells.

  8. Computer-aided design of modular protein devices: Boolean AND gene activation

    NASA Astrophysics Data System (ADS)

    Salis, H.; Kaznessis, Y. N.

    2006-12-01

    Many potentially useful synthetic gene networks require the expression of an engineered gene if and only if two different DNA-binding proteins exist in sufficient concentration. While some natural and engineered systems activate gene expression according to a logical AND-like behavior, they often utilize allosteric or cooperative protein-protein interactions, rendering their components unsuitable for a toolbox of modular parts for use in multiple applications. Here, we develop a quantitative model to demonstrate that a small system of interacting fusion proteins, called a protein device, can activate an engineered gene according to the Boolean AND behavior while using only modular protein domains and DNA sites. The fusion proteins are created from transactivating, DNA-binding, non-DNA binding, and protein-protein interaction domains along with the corresponding peptide ligands. Using a combined kinetic and thermodynamic model, we identify the characteristics of the molecular components and their rates of constitutive production that maximize the fidelity of AND behavior. These AND protein devices facilitate the creation of complex genetic programs and may be used to create gene therapies, biosensors and other biomedical and biotechnological applications that turn on gene expression only when multiple DNA-binding proteins are simultaneously present.

  9. Active implantable medical device EMI assessment for wireless power transfer operating in LF and HF bands

    NASA Astrophysics Data System (ADS)

    Hikage, Takashi; Nojima, Toshio; Fujimoto, Hiroshi

    2016-06-01

    The electromagnetic interference (EMI) imposed on active implantable medical devices by wireless power transfer systems (WPTSs) is discussed based upon results of in vitro experiments. The purpose of this study is to present comprehensive EMI test results gathered from implantable-cardiac pacemakers and implantable cardioverter defibrillators exposed to the electromagnetic field generated by several WPTSs operating in low-frequency (70 kHz-460 kHz) and high-frequency (6.78 MHz) bands. The constructed in vitro experimental test system based upon an Irnich’s flat torso phantom was applied. EMI test experiments are conducted on 14 types of WPTSs including Qi-compliant system and EV-charging WPT system mounted on current production EVs. In addition, a numerical simulation model for active implantable medical device (AIMD) EMI estimation based on the experimental test system is newly proposed. The experimental results demonstrate the risk of WPTSs emitting intermittent signal to affect the correct behavior of AIMDs when operating at very short distances. The proposed numerical simulation model is applicable to obtain basically the EMI characteristics of various types of WPTSs.

  10. Stimulus-active polymer actuators for next-generation microfluidic devices

    NASA Astrophysics Data System (ADS)

    Hilber, Wolfgang

    2016-08-01

    Microfluidic devices have not yet evolved into commercial off-the-shelf products. Although highly integrated microfluidic structures, also known as lab-on-a-chip (LOC) and micrototal-analysis-system (µTAS) devices, have consistently been predicted to revolutionize biomedical assays and chemical synthesis, they have not entered the market as expected. Studies have identified a lack of standardization and integration as the main obstacles to commercial breakthrough. Soft microfluidics, the utilization of a broad spectrum of soft materials (i.e., polymers) for realization of microfluidic components, will make a significant contribution to the proclaimed growth of the LOC market. Recent advances in polymer science developing novel stimulus-active soft-matter materials may further increase the popularity and spreading of soft microfluidics. Stimulus-active polymers and composite materials change shape or exert mechanical force on surrounding fluids in response to electric, magnetic, light, thermal, or water/solvent stimuli. Specifically devised actuators based on these materials may have the potential to facilitate integration significantly and hence increase the operational advantage for the end-user while retaining cost-effectiveness and ease of fabrication. This review gives an overview of available actuation concepts that are based on functional polymers and points out promising concepts and trends that may have the potential to promote the commercial success of microfluidics.

  11. New cosurface capacitive stimulators for the development of active osseointegrative implantable devices

    PubMed Central

    Soares dos Santos, Marco P.; Marote, Ana; Santos, T.; Torrão, João; Ramos, A.; Simões, José A. O.; da Cruz e Silva, Odete A. B.; Furlani, Edward P.; Vieira, Sandra I.; Ferreira, Jorge A. F.

    2016-01-01

    Non-drug strategies based on biophysical stimulation have been emphasized for the treatment and prevention of musculoskeletal conditions. However, to date, an effective stimulation system for intracorporeal therapies has not been proposed. This is particularly true for active intramedullary implants that aim to optimize osseointegration. The increasing demand for these implants, particularly for hip and knee replacements, has driven the design of innovative stimulation systems that are effective in bone-implant integration. In this paper, a new cosurface-based capacitive system concept is proposed for the design of implantable devices that deliver controllable and personalized electric field stimuli to target tissues. A prototype architecture of this system was constructed for in vitro tests, and its ability to deliver controllable stimuli was numerically analyzed. Successful results were obtained for osteoblastic proliferation and differentiation in the in vitro tests. This work provides, for the first time, a design of a stimulation system that can be embedded in active implantable devices for controllable bone-implant integration and regeneration. The proposed cosurface design holds potential for the implementation of novel and innovative personalized stimulatory therapies based on the delivery of electric fields to bone cells. PMID:27456818

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

    SciTech Connect

    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.

  13. Origami-inspired active graphene-based paper for programmable instant self-folding walking devices

    PubMed Central

    Mu, Jiuke; Hou, Chengyi; Wang, Hongzhi; Li, Yaogang; Zhang, Qinghong; Zhu, Meifang

    2015-01-01

    Origami-inspired active graphene-based paper with programmed gradients in vertical and lateral directions is developed to address many of the limitations of polymer active materials including slow response and violent operation methods. Specifically, we used function-designed graphene oxide as nanoscale building blocks to fabricate an all-graphene self-folding paper that has a single-component gradient structure. A functional device composed of this graphene paper can (i) adopt predesigned shapes, (ii) walk, and (iii) turn a corner. These processes can be remote-controlled by gentle light or heating. We believe that this self-folding material holds potential for a wide range of applications such as sensing, artificial muscles, and robotics. PMID:26601135

  14. INVITED PAPER: Application of an active device for helicopter noise reduction in JAXA

    NASA Astrophysics Data System (ADS)

    Saito, Shigeru; Kobiki, Noboru; Tanabe, Yasutada

    2010-02-01

    Important issues in noise problems for current helicopters are described. An active tab (AT) was developed as a new active device for noise/vibration reduction under research cooperation between Japan Aerospace Exploration Agency (JAXA) and Kawada Industries, Inc. The wind tunnel test was conducted in order to investigate the effectiveness of the AT on the aeroacoustic characteristics of a helicopter. From the wind tunnel test, the capability of reducing blade vortex interaction (BVI) noise by an AT was verified. A new control law using instantaneous pressure change on a blade during BVI phenomena was introduced and applied to the wind tunnel testing. This new control law shows reasonable controllability for helicopter noise reduction. Furthermore, in order to analyze noise characteristics, the advanced computational fluid dynamics (CFD) code named JAXA_ov3d was developed in JAXA and extended to include CFD-CSD (computational structure dynamics) coupling by using the beam theory for blade deformation.

  15. Validation of a computed radiography device to monitor the HIV-1 RNase H activity

    NASA Astrophysics Data System (ADS)

    Esposito, F.; Fanti, V.; Marzeddu, R.; Randaccio, P.; Tramontano, E.; Zinzula, L.

    2009-08-01

    A commercially available computed radiography (CR) system for dental radiography was used to produce images from radiolabeled polyacrilamide gel electrophoresis (PAGE) assays. Typically, similar investigations require specific and expensive autoradiography devices. The CR unit was characterized in terms of sensitivity and fading by means of a 90Sr source that well simulates the experimental conditions, and then used for quantitative analyses of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) polymerase-independent ribonuclease H (RNase H) activity monitored by PAGE analysis. The results showed that the present methodology allows quantifying effectively the RNase H catalyses and that the obtained data are in good agreement with previous reference works. Finally, in order to further validate the present method in terms of relationship between enzyme activity, the rate of products formation and signal intensity, a PAGE analyses of the HIV-1 RNase H inhibition by the known diketo acid derivative RDS1643 was carried out.

  16. Berkeley Lab's Cool Your School Program

    ScienceCinema

    Ivan Berry

    2016-07-12

    Cool Your School is a series of 6th-grade, classroom-based, science activities rooted in Berkeley Lab's cool-surface and cool materials research and aligned with California science content standards. The activities are designed to build knowledge, stimulate curiosity, and carry the conversation about human-induced climate change, and what can be done about it, into the community.

  17. Berkeley Lab's Cool Your School Program

    SciTech Connect

    Ivan Berry

    2012-07-30

    Cool Your School is a series of 6th-grade, classroom-based, science activities rooted in Berkeley Lab's cool-surface and cool materials research and aligned with California science content standards. The activities are designed to build knowledge, stimulate curiosity, and carry the conversation about human-induced climate change, and what can be done about it, into the community.

  18. Sensor-actuator coupled device for active tracheal tube using solid polymer electrolyte membrane

    NASA Astrophysics Data System (ADS)

    Ihara, Tadashi; Nakamura, Taro; Mukai, Toshiharu; Asaka, Kinji

    2007-04-01

    A sensor-actuator coupled device was developed using solid polymer electrolyte membrane (SPM) as an active tracheal tube for ventilator. Active tracheal tube is a novel type of tube for ventilator that removes patient's phlegm automatically upon sensing the narrowing of trachea by phlegm. This type of active tube is extremely useful in clinical settings as currently the sole measure to remove phlegm from patient's tube is to do it manually by a nurse every few hours. As SPM works both as a sensor and an actuator, an effective compact device was developed. SPM based sensor-actuator coupled device was fabricated with modified gold plating method. Prepared SPM was fixed as an array on a plastic pipe of diameter 22 mm and was connected to a ventilator circuit and driven by a ventilator with a volume control ventilation (VCV) mode. SPM was connected both to a sensing unit and an actuation unit. Generated voltage developed by the membrane with the setting of the maximum pressure from 5 cmH IIO to 20 cmH IIO was in order of several hundred μV. SPM sensor demonstrated a biphasic response to the ventilator flow. The sensor data showed nearly linearly proportional voltage development to the intra-tracheal pressure. The sensed signal was filtered and digitized with an A/D converting unit on a PC board. A real time operating program was used to detect the sensed signal that indicates the narrowing of trachea. The program then activated a driving signal to control the actuation of the membrane. The signal was sent to a D/A converting unit. The output of the D/A unit was sent to an amplifier and the galvanostat unit which drives the membrane with constant current regardless of the change in the load. It was demonstrated that the sensor-actuator unit detects the narrowing of trachea within several hundreds milli-seconds and responds by actuating the same membrane with the driving voltage of 3-4 V and driving current of several hundred milli-ampere for each membrane. SPM array

  19. Superconducting magnet cooling system

    DOEpatents

    Vander Arend, Peter C.; Fowler, William B.

    1977-01-01

    A device is provided for cooling a conductor to the superconducting state. The conductor is positioned within an inner conduit through which is flowing a supercooled liquid coolant in physical contact with the conductor. The inner conduit is positioned within an outer conduit so that an annular open space is formed therebetween. Through the annular space is flowing coolant in the boiling liquid state. Heat generated by the conductor is transferred by convection within the supercooled liquid coolant to the inner wall of the inner conduit and then is removed by the boiling liquid coolant, making the heat removal from the conductor relatively independent of conductor length.

  20. Electrochromic devices

    DOEpatents

    Allemand, Pierre M.; Grimes, Randall F.; Ingle, Andrew R.; Cronin, John P.; Kennedy, Steve R.; Agrawal, Anoop; Boulton, Jonathan M.

    2001-01-01

    An electrochromic device is disclosed having a selective ion transport layer which separates an electrochemically active material from an electrolyte containing a redox active material. The devices are particularly useful as large area architectural and automotive glazings due to there reduced back reaction.

  1. Use of hypometabolic TRIS extenders and high cooling rate refrigeration for cryopreservation of stallion sperm: presence and sensitivity of 5' AMP-activated protein kinase (AMPK).

    PubMed

    Córdova, Alex; Strobel, Pablo; Vallejo, Andrés; Valenzuela, Pamela; Ulloa, Omar; Burgos, Rafael A; Menarim, Bruno; Rodríguez-Gil, Joan Enric; Ratto, Marcelo; Ramírez-Reveco, Alfredo

    2014-12-01

    This study evaluated the effect of the use of hypometabolic TRIS extenders in the presence or the absence of AMPK activators as well as the utilization of high cooling rates in the refrigeration step on the freezability of stallion sperm. Twelve ejaculates were cryopreserved using Botucrio® as a control extender and a basic TRIS extender (HM-0) separately supplemented with 10 mM metformin, 2mM 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), 2 mM Adenosine monophosphate (AMP), 40 μM compound C AMPK inhibitor or 2 mM AMP+40 μM compound C. Our results showed that the utilization of a hypometabolic TRIS extender supplemented or not with AMP or metformin significantly improves stallion sperm freezability when compared with a commercial extender. Additionally, high cooling rates do not affect stallion sperm quality after cooling and post-thawing. Finally, stallion spermatozoa present several putative AMPK sperm isoforms that do not seem to respond to classical activators, but do respond to the Compound C inhibitor.

  2. Heat tube device

    NASA Technical Reports Server (NTRS)

    Khattar, Mukesh K. (Inventor)

    1990-01-01

    The present invention discloses a heat tube device through which a working fluid can be circulated to transfer heat to air in a conventional air conditioning system. The heat tube device is disposable about a conventional cooling coil of the air conditioning system and includes a plurality of substantially U-shaped tubes connected to a support structure. The support structure includes members for allowing the heat tube device to be readily positioned about the cooling coil. An actuatable adjustment device is connected to the U-shaped tubes for allowing, upon actuation thereof, for the heat tubes to be simultaneously rotated relative to the cooling coil for allowing the heat transfer from the heat tube device to air in the air conditioning system to be selectively varied.

  3. SIMULATING THE COOLING FLOW OF COOL-CORE CLUSTERS

    SciTech Connect

    Li Yuan; Bryan, Greg L.

    2012-03-01

    We carry out high-resolution adaptive mesh refinement simulations of a cool core cluster, resolving the flow from Mpc scales down to pc scales. We do not (yet) include any active galactic nucleus (AGN) heating, focusing instead on cooling in order to understand how gas reaches the supermassive black hole at the center of the cluster. We find that, as the gas cools, the cluster develops a very flat temperature profile, undergoing a cooling catastrophe only in the central 10-100 pc of the cluster. Outside of this region, the flow is smooth, with no local cooling instabilities, and naturally produces very little low-temperature gas (below a few keV), in agreement with observations. The gas cooling in the center of the cluster rapidly forms a thin accretion disk. The amount of cold gas produced at the very center grows rapidly until a reasonable estimate of the resulting AGN heating rate (assuming even a moderate accretion efficiency) would overwhelm cooling. We argue that this naturally produces a thermostat which links the cooling of gas out to 100 kpc with the cold gas accretion in the central 100 pc, potentially closing the loop between cooling and heating. Isotropic heat conduction does not affect the result significantly, but we show that including the potential well of the brightest cluster galaxy is necessary to obtain the correct result. Also, we found that the outcome is sensitive to resolution, requiring very high mass resolution to correctly reproduce the small transition radius.

  4. Temporal leukocyte numbers and granulocyte activation in pulsatile and rotary ventricular assist device patients.

    PubMed

    Woolley, Joshua R; Teuteberg, Jeffrey J; Bermudez, Christian A; Bhama, Jay K; Lockard, Kathleen L; Kormos, Robert L; Wagner, William R

    2014-06-01

    Individual ventricular assist device (VAD) design may affect leukocytes and impact immunity. Few studies have presented leukocyte and infection profiles in VAD patients over the course of the implant period. CD11b (MAC-1) expression on granulocytes is an indicator of activation during inflammation, mediating extravasation and the release of reactive oxygen species in tissue. No reported studies have presented MAC-1 expression on circulating granulocytes in VAD patients. Fifty-six patients implanted at a single center with a HeartMate II (HMII; n = 32), HeartWare (HW; n = 12), or Thoratec pneumatic VAD (PVAD; n = 12) between 1999 and 2011 were followed for 120 days of support. The leukocyte profiles and infectious events of all patients were evaluated; additionally, a subset had MAC-1 expression on circulating granulocytes was measured (HMII n = 9; HW n = 7; PVAD n = 4). All groups exhibited a significant peak in leukocyte numbers at postoperative day (POD) 14 while simultaneously experiencing a significant decrease in hematocrit. HMII patients exhibited a 3.2-fold increase in granulocyte MAC-1 expression at POD 14, and the temporal trend over the implant period differed from that experienced by HW patients. Further, HW patients experienced significantly fewer infection events. Alterations in leukocyte profiles and granulocyte activation experienced by VAD patients appear to be device-specific. Elevations in leukocyte activation may be related to an increased risk for infection, although the specific relationship between these phenomena in this patient group is not known.

  5. REACTOR COOLING

    DOEpatents

    Quackenbush, C.F.

    1959-09-29

    A nuclear reactor with provisions for selectively cooling the fuel elements is described. The reactor has a plurality of tubes extending throughout. Cylindrical fuel elements are disposed within the tubes and the coolant flows through the tubes and around the fuel elements. The fuel elements within the central portion of the reactor are provided with roughened surfaces of material. The fuel elements in the end portions of the tubes within the reactor are provlded with low conduction jackets and the fuel elements in the region between the central portion and the end portions are provided with smooth surfaces of high heat conduction material.

  6. Real-Time Control of Biological Motor Activity using Graphene-polymer Hybrid Bioenergy Storage Device

    NASA Astrophysics Data System (ADS)

    Lee, Dong; Byun, Kyung-Eun; Choi, Dong; Kim, Eunji; Kim, Daesan; Seo, David; Yang, Heejun; Seo, Sunae; Hong, Seunghun; Hybrid Nanodevice Lab Team; Samsung Research Park Team

    2013-03-01

    Biological motors have been drawing an attention as a key component for highly efficient nanomechanical systems. For such applications, many researchers have tried to control the activity of motor proteins through various methods such as microfluidics or UV-active compounds. However, these methods have some limitations such as the incapability of controlling local biomotor activity and a slow response rate. Herein, we developed a graphene-polymer hybrid nanostructure-based bioenergy storage device which enables the real-time control of biomotor activity. In this strategy, graphene layers functionalized with amine groups were utilized as a transparent electrode supporting the motility of biomotors. And conducting polymer patterns doped with adenosine triphosphate (ATP) were electrically deposited on the graphene and utilized for the fast release of ATP by electrical stimuli through the graphene. Such controlled release of ATP allowed us to control the motility of actin filaments propelled by myosin biomotors in real time. This strategy should enable integrated nanodevices for the real-time control of biological motors to the nanodevices, which can be a significant stepping stone toward hybrid nanomechanical systems based on motor proteins.

  7. Thermal Wick Cooling for Vibroacoustic Transducers

    DTIC Science & Technology

    2009-09-25

    affecting vibrational characteristics of the transducer . (2) Description of the Prior Art [0004] Vibroacoustic transducers , such as piezoceramic tonpilz ...Distribution is unlimited 20091013084 Attorney Docket No. 84708 THERMAL WICK COOLING FOR VIBROACOUSTIC TRANSDUCERS STATEMENT OF GOVERNMENT INTEREST...INVENTION (1) Field of the Invention [0003] The present invention provides a device for cooling a vibroacoustic transducer without adversely

  8. Electro-active device using radial electric field piezo-diaphragm for sonic applications

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Fox, Robert L. (Inventor)

    2005-01-01

    An electro-active transducer for sonic applications includes a ferroelectric material sandwiched by first and second electrode patterns to form a piezo-diaphragm coupled to a mounting frame. When the device is used as a sonic actuator, the first and second electrode patterns are configured to introduce an electric field into the ferroelectric material when voltage is applied to the electrode patterns. When the device is used as a sonic sensor, the first and second electrode patterns are configured to introduce an electric field into the ferroelectric material when the ferroelectric material experiences deflection in a direction substantially perpendicular thereto. In each case, the electrode patterns are designed to cause the electric field to: i) originate at a region of the ferroelectric material between the first and second electrode patterns, and ii) extend radially outward from the region of the ferroelectric material (at which the electric field originates) and substantially parallel to the plane of the ferroelectric material. The mounting frame perimetrically surrounds the peizo-diaphragm and enables attachment of the piezo-diaphragm to a housing.

  9. Active photonic devices based on colloidal semiconductor nanocrystals and organometallic halide perovskites

    NASA Astrophysics Data System (ADS)

    Suárez Alvarez, Isaac

    2016-10-01

    Semiconductor nanocrystals have arisen as outstanding materials to develop a new generation of optoelectronic devices. Their fabrication under simple and low cost colloidal chemistry methods results in cheap nanostructures able to provide a wide range of optical functionalities. Their attractive optical properties include a high absorption cross section below the band gap, a high quantum yield emission at room temperature, or the capability of tuning the band-gap with the size or the base material. In addition, their solution process nature enables an easy integration on several substrates and photonic structures. As a consequence, these nanoparticles have been extensively proposed to develop several photonic applications, such as detection of light, optical gain, generation of light or sensing. This manuscript reviews the great effort undertaken by the scientific community to construct active photonic devices based on these nanoparticles. The conditions to demonstrate stimulated emission are carefully studied by comparing the dependence of the optical properties of the nanocrystals with their size, shape and composition. In addition, this paper describes the design of different photonic architectures (waveguides and cavities) to enhance the generation of photoluminescence, and hence to reduce the threshold of optical gain. Finally, semiconductor nanocrystals are compared to organometallic halide perovskites, as this novel material has emerged as an alternative to colloidal nanoparticles.

  10. Modelling and experimental validation of Textile Pockets based active inflatable device.

    PubMed

    Mehmood, A; Basset, M; Orjuela, R; Dupuis, R; Drean, J Y

    2014-11-01

    This paper aims with the mathematical modelling of an active inflatable device. This device is composed of a compressor, an Electro-pneumatic Pressure Converter (EPC) and an Inflatable Textile fabric Pocket (ITP). The later has interesting mechanical properties and is fabricated using Jacquard knitting technique which allows automatic production of unlimited varieties of pattern weaving without any mould. Thanks to these features, these ITPs have provided a better alternative to the classical airbags made by stretchable polymer material. The proposed mathematical model is obtained by combining sub-models of two main parts of the whole system. In this way, a generalised and flexible model is obtained which can easily take into consideration the ITPs of different shapes. The pressure dynamics inside the ITP are considered by taking into account the air flow rate, variation of the volume of ITP and the length of pneumatic lines joining ITP with compressed air source. The parameters of the whole mathematical model are obtained via identification techniques. The effectiveness of the model is assessed through several experimental tests with the help of a servo hydraulic fatigue testing machine.

  11. PROGRESS ON INSERTION DEVICE RELATED ACTIVITIES AT THE NSLS-II AND ITS FUTURE PLANS

    SciTech Connect

    Tanabe, T.; Chubar, O.; Corwin, T.; Harder, D. A.; He, P.; Rank, J.; Rakowsky, G.; Spataro, C.

    2010-05-23

    National Synchrotron Light Source-II (NSLS-II) project is now in the construction stage. A new insertion device (ID) magnetic measurement facility (MMF) is being set up at Brookhaven National Laboratory in order to satisfy the stringent requirement on the magnetic field measurement of IDs. ISO-Class7 temperature stabilized clean room is being constructed for this purpose. A state-of-the-art Hall probe bench and integrated field measurement system will be installed therein. IDs in the project baseline scope include six damping wigglers, two elliptically polarizing undulators (EPUs), three 3.0m long in-vacuum undulators (IVUs) and one 1.5m long IVU. Three-pole wigglers with peak field over 1 Tesla will be utilized to accommodate the users of bending magnet radiation at the NSLS. Future plans includes: (1) an in-vacuum magnetic measurement system, (2) use of PrFeB magnet for improved cryo undulator, (3) development of advanced optimization program for sorting and shimming of IDs, (4) development of a closed loop He gas refrigerator, (5) switchable quasi-periodic EPU. Design features of the baseline devices, IDMMF and the future plans for NSLS-II ID activities are described.

  12. Three-dimensional kinematic analysis of active cervical spine motion by using a multifaceted marker device.

    PubMed

    Tsunezuka, Hiroaki; Kato, Daishiro; Okada, Satru; Ishihara, Shunta; Shimada, Junichi

    2013-01-01

    Assessing cervical range of motion (CROM) is an important part of the clinical evaluation of patients with conditions such as whiplash syndrome. This study aimed to develop a convenient and accurate system involving multifaceted marker device (MMD)-based assessment of 3-dimensional (3D) dynamic coupled CROM and joint angular velocity. We used an infrared optical tracking system and our newly developed MMD that solved problems such as marker shielding and reflection angle associated with the optical tracking devices and enabled sequential and accurate analysis of the 3D dynamic movement of the polyaxial joint and other structurally complicated joints. The study included 30 asymptomatic young male volunteers (age, 22-27 years). The MMD consisted of 5 surfaces and 5 markers and was attached to the participant's forehead. We measured active CROM (axial rotation, flexion/extension, and lateral bending) and joint angular velocity by the MMD. The MMD was easy to use, safe for patients and operators, could be constructed economically, and generated accurate data such as dynamic coupled CROM and angular velocity.

  13. 78 FR 46347 - Agency Information Collection Activities; Proposed Collection; Comment Request; Medical Devices...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-31

    ... international standards ``ISO 9001: Quality Systems Model for Quality Assurance in Design/Development... device CGMP requirements with QS specifications in the international standard ``ISO 9001: Quality Systems... Collection; Comment Request; Medical Devices Current Good Manufacturing Practice Quality System...

  14. 75 FR 36092 - Agency Information Collection Activities; Proposed Collection; Comment Request; Medical Devices...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-24

    ... international standards ``ISO 9001: Quality Systems Model for Quality Assurance in Design/Development... harmonizes device CGMP requirements with QS specifications in the international standard ``ISO 9001: Quality... Collection; Comment Request; Medical Devices: Current Good Manufacturing Practice Quality System...

  15. Changes in cervical muscle activity according to the traction force of an air-inflatable neck traction device

    PubMed Central

    Kang, Jong Ho; Park, Tae-Sung

    2015-01-01

    [Purpose] The purpose of this study was to analyze cervical muscle activity at different traction forces of an air-inflatable neck traction device. [Subjects] Eighteen males participated in this study. [Methods] The subjects put on an air-inflatable neck traction device and the traction forces administered were 40, 80, and 120 mmHg. The electromyography (EMG) signals of the splenius capitis, and upper trapezius were measured to assess the muscle activity. [Results] The muscle activity of the splenius capitis was significantly higher at 80, and 120 mmHg compared to 40 mmHg. The muscle activity of the upper trapezius did not show significant differences among the traction forces. [Conclusion] Our research result showed that the air-inflatable home neck traction device did not meet the condition of muscle relaxation. PMID:26504278

  16. Changes in cervical muscle activity according to the traction force of an air-inflatable neck traction device.

    PubMed

    Kang, Jong Ho; Park, Tae-Sung

    2015-09-01

    [Purpose] The purpose of this study was to analyze cervical muscle activity at different traction forces of an air-inflatable neck traction device. [Subjects] Eighteen males participated in this study. [Methods] The subjects put on an air-inflatable neck traction device and the traction forces administered were 40, 80, and 120 mmHg. The electromyography (EMG) signals of the splenius capitis, and upper trapezius were measured to assess the muscle activity. [Results] The muscle activity of the splenius capitis was significantly higher at 80, and 120 mmHg compared to 40 mmHg. The muscle activity of the upper trapezius did not show significant differences among the traction forces. [Conclusion] Our research result showed that the air-inflatable home neck traction device did not meet the condition of muscle relaxation.

  17. Nanostructure and strain effects in active thin films for novel electronic device applications

    NASA Astrophysics Data System (ADS)

    Yuan, Zheng

    2007-12-01

    There are many potential applications of ferroelectric thin films that take advantage of their unique dielectric and piezoelectric properties, such as tunable microwave devices and thin-film active sensors for structural health monitoring (SHM). However, many technical issues still restrict practical applications of ferroelectric thin films, including high insertion loss, limited figure of merit, soft mode effect, large temperature coefficients, and others. The main theme of this thesis is the advanced technique developments, and the new ferroelectric thin films syntheses and investigations for novel device applications. A novel method of additional doping has been adopted to (Ba,Sr)TiO 3 (BSTO) thin films on MgO. By introducing 2% Mn into the stoichiometric BSTO, Mn:BSTO thin films have shown a greatly enhanced dielectric tunability and a reduced insertion loss at high frequencies (10-30 GHz). A new record of a large tunability of 80% with a high dielectric constant of 3800 and an extra low dielectric loss of 0.001 at 1 MHz at room-temperature was achieved. Meanwhile, the new highly epitaxial ferroelectric (Pb,Sr)TiO3 (PSTO) thin films have been synthesized on (001) MgO substrates. PSTO films demonstrated excellent high frequency dielectric properties with high dielectric constants above 1420 and large dielectric tunabilities above 34% at room-temperature up to 20 GHz. In addition, a smaller temperature coefficient from 80 K to 300 K was observed in PSTO films compared to BSTO films. These results indicate that the Mn:BSTO and PSTO films are both good candidates for developing room-temperature tunable microwave devices. Furthermore, crystalline ferroelectric BaTiO3 (BTO) thin films have been deposited directly on metal substrate Ni through a unique in-situ substrate pre-oxidation treatment. The highly oriented nanopillar structural BTO films were grown on the buffered layers created by the pre-oxidation treatment. No interdiffusion or reaction was observed at the

  18. Active control of near-field coupling in conductively coupled microelectromechanical system metamaterial devices

    NASA Astrophysics Data System (ADS)

    Pitchappa, Prakash; Manjappa, Manukumara; Ho, Chong Pei; Qian, You; Singh, Ranjan; Singh, Navab; Lee, Chengkuo

    2016-03-01

    We experimentally report a structurally reconfigurable metamaterial for active switching of near-field coupling in conductively coupled, orthogonally twisted split ring resonators (SRRs) operating in the terahertz spectral region. Out-of-plane reconfigurable microcantilevers integrated into the dark SRR geometry are used to provide active frequency tuning of dark SRR resonance. The geometrical parameters of individual SRRs are designed to have identical inductive-capacitive resonant frequency. This allows for the excitation of classical analogue of electromagnetically induced transparency (EIT) due to the strong conductive coupling between the SRRs. When the microcantilevers are curved up, the resonant frequency of dark SRR blue-shifts and the EIT peak is completely modulated while the SRRs are still conductively connected. EIT modulation contrast of ˜50% is experimentally achieved with actively switchable group delay of ˜2.5 ps. Electrical control, miniaturized size, and readily integrable fabrication process of the proposed structurally reconfigurable metamaterial make it an ideal candidate for the realization of various terahertz communication devices such as electrically controllable terahertz delay lines, buffers, and tunable data-rate channels.

  19. Modeling activities on the negative-ion-based Neutral Beam Injectors of the Large Helical Device

    SciTech Connect

    Agostinetti, P.; Antoni, V.; Chitarin, G.; Pilan, N.; Serianni, G.; Veltri, P.; Cavenago, M.; Nakano, H.; Takeiri, Y.; Tsumori, K.

    2011-09-26

    At the National Institute for Fusion Science (NIFS) large-scaled negative ion sources have been widely used for the Neutral Beam Injectors (NBIs) mounted on the Large Helical Device (LHD), which is the world-largest superconducting helical system. These injectors have achieved outstanding performances in terms of beam energy, negative-ion current and optics, and represent a reference for the development of heating and current drive NBIs for ITER.In the framework of the support activities for the ITER NBIs, the PRIMA test facility, which includes a RF-drive ion source with 100 keV accelerator (SPIDER) and a complete 1 MeV Neutral Beam system (MITICA) is under construction at Consorzio RFX in Padova.An experimental validation of the codes has been undertaken in order to prove the accuracy of the simulations and the soundness of the SPIDER and MITICA design. To this purpose, the whole set of codes have been applied to the LHD NBIs in a joint activity between Consorzio RFX and NIFS, with the goal of comparing and benchmarking the codes with the experimental data. A description of these modeling activities and a discussion of the main results obtained are reported in this paper.

  20. Continuous Monitoring of Electrical Activity of Pancreatic β-Cells Using Semiconductor-Based Biosensing Devices

    NASA Astrophysics Data System (ADS)

    Sakata, Toshiya; Sugimoto, Haruyo

    2011-02-01

    The electrical activity of rat pancreatic β-cells caused by introduction of glucose was directly and noninvasively detected using a cell-based field-effect transistor (FET). Rat pancreatic β-cells were adhered to the gate sensing surface of the cell-based FET. The principle of cell-based FETs is based on the detection of charge density changes such as pH variation at the interface between the cell membrane and the gate surface. The gate surface potential of pancreatic β-cell-based FET increased continuously after introduction of glucose at a high concentration of 10 mg/ml. This result indicates that the electrical activity of β-cells was successfully monitored on the basis of pH changes, i.e., increase in the concentration of hydrogen ions, at the cell/gate interface using the pancreatic β-cell-based FET. We assume that the pH variation based on hydrogen ion accumulation at the cell/gate interface was induced by activation of respiration accompanied by insulin secretion process following glucose addition. The platform based on the field-effect devices is suitable for application in a real-time, noninvasive, and label-free detection system for cell functional analyses.

  1. Activity monitoring using a mHealth device and correlations with psychopathology in patients with chronic schizophrenia.

    PubMed

    Shin, Seunghwan; Yeom, Chan-Woo; Shin, Cheolmin; Shin, Jae-Hyun; Jeong, Jae Hoon; Shin, Jung Uk; Lee, Young Ryeol

    2016-12-30

    There are few studies of mobile-Health (mHealth) device application with schizophrenic patients. We aimed to quantitatively assess patient's activity and the relationship between their physical activity and the severity of their psychopathologies. Then we attempted to identify the patients who required intervention and evaluated the feasibility of using the mHealth device. A total of 61 of the 76 available hospitalized patients with chronic schizophrenia who participated in the activity programs were enrolled. They wore a mHealth device for a week to assess their activity (steps/day). The Positive and Negative Syndrome Scale (PANSS) was completed by the subjects. As a result, the positive subscale of the PANSS and the positive and negative factors of the PANSS 5-factor structure showed a predictive value for low levels of physical activity. The group of subjects with a high total PANSS score had a significantly lower level of physical activity than the other groups. In conclusion, physical activity showed a significant association with positive symptoms as well as negative symptoms. The mHealth device showed relatively good feasibility for schizophrenic patients. We should pay more attention to the activity of patients with high PANSS scores.

  2. The dance of heating and cooling in galaxy clusters: three-dimensional simulations of self-regulated active galactic nuclei outflows

    NASA Astrophysics Data System (ADS)

    Gaspari, M.; Melioli, C.; Brighenti, F.; D'Ercole, A.

    2011-02-01

    It is now widely accepted that heating processes play a fundamental role in galaxy clusters, struggling in an intricate but fascinating ‘dance' with its antagonist, radiative cooling. Last-generation observations, especially X-ray, are giving us tiny hints about the notes of this endless ballet. Cavities, shocks, turbulence and wide absorption lines indicate that the central active nucleus is injecting a huge amount of energy in the intracluster medium. However, which is the real dominant engine of self-regulated heating? One of the models we propose is massive subrelativistic outflows, probably generated by a wind disc or just the result of the entrainment on kpc scale by the fast radio jet. Using a modified version of the adaptive mesh refinement code FLASH 3.2, we have explored several feedback mechanisms that self-regulate the mechanical power. Two are the best schemes that answer our primary question, that is, quenching cooling flow and at the same time preserving a cool core appearance for a long-term evolution (7 Gyr): one is more explosive (with efficiencies ˜ 5 × 10-3-10-2), triggered by central cooled gas, and the other is gentler, ignited by hot gas Bondi accretion (with ɛ= 0.1). These three-dimensional simulations show that the total energy injected is not the key aspect, but the results strongly depend on how energy is given to the intracluster medium. We follow the dynamics of the best models (temperature, density, surface brightness maps and profiles) and produce many observable predictions: buoyant bubbles, ripples, turbulence, iron abundance maps and hydrostatic equilibrium deviation. We present an in-depth discussion of the merits and flaws of all our models, with a critical eye towards observational concordance.

  3. Energy expenditure prediction via a footwear-based physical activity monitor: Accuracy and comparison to other devices

    NASA Astrophysics Data System (ADS)

    Dannecker, Kathryn

    2011-12-01

    Accurately estimating free-living energy expenditure (EE) is important for monitoring or altering energy balance and quantifying levels of physical activity. The use of accelerometers to monitor physical activity and estimate physical activity EE is common in both research and consumer settings. Recent advances in physical activity monitors include the ability to identify specific activities (e.g. stand vs. walk) which has resulted in improved EE estimation accuracy. Recently, a multi-sensor footwear-based physical activity monitor that is capable of achieving 98% activity identification accuracy has been developed. However, no study has compared the EE estimation accuracy for this monitor and compared this accuracy to other similar devices. Purpose . To determine the accuracy of physical activity EE estimation of a footwear-based physical activity monitor that uses an embedded accelerometer and insole pressure sensors and to compare this accuracy against a variety of research and consumer physical activity monitors. Methods. Nineteen adults (10 male, 9 female), mass: 75.14 (17.1) kg, BMI: 25.07(4.6) kg/m2 (mean (SD)), completed a four hour stay in a room calorimeter. Participants wore a footwear-based physical activity monitor, as well as three physical activity monitoring devices used in research: hip-mounted Actical and Actigraph accelerometers and a multi-accelerometer IDEEA device with sensors secured to the limb and chest. In addition, participants wore two consumer devices: Philips DirectLife and Fitbit. Each individual performed a series of randomly assigned and ordered postures/activities including lying, sitting (quietly and using a computer), standing, walking, stepping, cycling, sweeping, as well as a period of self-selected activities. We developed branched (i.e. activity specific) linear regression models to estimate EE from the footwear-based device, and we used the manufacturer's software to estimate EE for all other devices. Results. The shoe

  4. Detectors and cooling technology for direct spectroscopic biosignature characterization

    NASA Astrophysics Data System (ADS)

    Rauscher, Bernard J.; Canavan, Edgar R.; Moseley, Samuel H.; Sadleir, John E.; Stevenson, Thomas

    2016-10-01

    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 photons s-1 pixel in the visible and near-infrared. We then discuss potential areas for further testing and/or development to meet these needs using noncryogenic detectors (electron multiplying charge coupled devices, HgCdTe array, HgCdTe APD array), and cryogenic single-photon detectors (microwave kinetic inductance device arrays and transition-edge sensor microcalorimeter arrays). Noncryogenic detectors are compatible with the passive cooling that is strongly preferred by coronagraphic missions but would add nonnegligible noise. Cryogenic detectors would require active cooling, but in return, deliver nearly quantum-limited performance. Based on the flight dynamics of past NASA missions, we discuss reasonable vibration expectations for a large UV-Optical-IR space telescope (LUVOIR) and preliminary cooling concepts that could potentially fit into a vibration budget without being the largest element. We believe that a cooler that meets the stringent vibration needs of a LUVOIR is also likely to meet those of a starshade-based Habitable Exoplanet Imaging Mission.

  5. A glasses-type wearable device for monitoring the patterns of food intake and facial activity

    PubMed Central

    Chung, Jungman; Chung, Jungmin; Oh, Wonjun; Yoo, Yongkyu; Lee, Won Gu; Bang, Hyunwoo

    2017-01-01

    Here we present a new method for automatic and objective monitoring of ingestive behaviors in comparison with other facial activities through load cells embedded in a pair of glasses, named GlasSense. Typically, activated by subtle contraction and relaxation of a temporalis muscle, there is a cyclic movement of the temporomandibular joint during mastication. However, such muscular signals are, in general, too weak to sense without amplification or an electromyographic analysis. To detect these oscillatory facial signals without any use of obtrusive device, we incorporated a load cell into each hinge which was used as a lever mechanism on both sides of the glasses. Thus, the signal measured at the load cells can detect the force amplified mechanically by the hinge. We demonstrated a proof-of-concept validation of the amplification by differentiating the force signals between the hinge and the temple. A pattern recognition was applied to extract statistical features and classify featured behavioral patterns, such as natural head movement, chewing, talking, and wink. The overall results showed that the average F1 score of the classification was about 94.0% and the accuracy above 89%. We believe this approach will be helpful for designing a non-intrusive and un-obtrusive eyewear-based ingestive behavior monitoring system. PMID:28134303

  6. Active Learning Approaches by Visualizing ICT Devices with Milliseconds Resolution for Deeper Understanding in Physics

    NASA Astrophysics Data System (ADS)

    Kobayashi, Akizo; Okiharu, Fumiko

    2010-07-01

    We are developing various modularized materials in physics education to overcome students' misconceptions by use of ICT, i.e. video analysis software and ultra-high-speed digital movies, motion detector, force sensors, current and voltage probes, temperature sensors etc. Furthermore, we also present some new modules of active learning approaches on electric circuit using high speed camera and voltage probes with milliseconds resolution. We are now especially trying to improve conceptual understanding by use of ICT devices with milliseconds resolution in various areas of physics education We give some modules of mass measurements by video analysis of collision phenomena by using high speed cameras—Casio EX-F1(1200 fps), EX-FH20(1000 fps) and EX-FC100/150(1000 fps). We present several new modules on collision phenomena to establish deeper understanding of conservation laws of momentum. We discuss some effective results of trial on a physics education training courses for science educators, and those for science teachers during the renewal years of teacher's license after every ten years in Japan. Finally, we discuss on some typical results of pre-test and post-test in our active learning approaches based on ICT, i.e. some evidence on improvements of physics education (increasing ratio of correct answer are 50%-level).

  7. Self-Assembled, Redox-Active Graphene Electrodes for High-Performance Energy Storage Devices.

    PubMed

    Liu, Tianyuan; Kavian, Reza; Kim, Inkyu; Lee, Seung Woo

    2014-12-18

    Graphene-based materials have been utilized as a promising approach in designing high-performance electrodes for energy storage devices. In line with this approach, functionalized graphene electrodes have been self-assembled from the dispersion of graphene oxide (GO) in water at a low temperature of 80 °C using tetrahydroxyl-1,4-benzoquinone (THQ) as both the reducing and redox-active functionalization agent. We correlated the electrochemical performance of the electrode with surface oxygen chemistry, confirming the role of THQ for the reduction and redox-active functionalization process. The assembled graphene electrodes have a 3D hierarchical porous structure, which can facilitate electronic and ionic transport to support fast charge storage reactions. Utilizing the surface redox reactions introduced by THQ, the functionalized graphene electrodes exhibit high gravimetric capacities of ∼165 mA h/g in Li cells and ∼120 mA h/g in Na cells with high redox potentials over ∼3 V versus Li or Na, proposing promising positive electrodes for both Li and Na ion batteries.

  8. Propeller-based wireless device for active capsular endoscopy in the gastric district.

    PubMed

    Tortora, Giuseppe; Valdastri, Pietro; Susilo, Ekawahyu; Menciassi, Arianna; Dario, Paolo; Rieber, Fabian; Schurr, Marc Oliver

    2009-01-01

    An innovative approach to active locomotion for capsular endoscopy in the gastric district is reported in this paper. Taking advantage of the ingestion of 500 ml of transparent liquid by the patient, an effective distension of the stomach is safely achieved for a timeframe of approximately 30 minutes. Given such a scenario, an active swallowable capsule able to navigate inside the stomach thanks to a four propeller system has been developed. The capsule is 15 mm in diameter and 30 mm in length, and it is composed of a supporting shell containing a wireless microcontroller, a battery and four motors. The motors enable the rotation of propellers located in the rear side of the device, thus obtaining a reliable locomotion and steering of the capsule in all directions in a liquid. The power consumption has been properly optimized in order to achieve an operative lifetime consistent with the time of the diagnostic inspection of the gastric district, assumed to be no more than 30 minutes. The capsule can be easily remotely controlled by the endoscopist using a joystick together with a purposely developed graphical user interface. The capsule design, prototyping, in vitro, ex vivo and preliminary in vivo tests are described in this work.

  9. Active Clearance of Chest Tubes Reduces Re-Exploration for Bleeding After Ventricular Assist Device Implantation

    PubMed Central

    Davis, Mary E.; Haglund, Nicholas A.; Perrault, Louis; Kushwaha, Sudhir S.; Stulak, John M.; Boyle, Edward M.

    2016-01-01

    Chest tubes are utilized to evacuate shed blood after left ventricular assist device (LVAD) implantation, however, they can become clogged, leading to retained blood. We implemented a protocol for active tube clearance (ATC) of chest tubes to determine if this might reduce interventions for retained blood. A total of 252 patients underwent LVAD implantation. Seventy-seven patients had conventional chest tube drainage (group 1), whereas 175 patients had ATC (group 2). A univariate and multivariate analysis adjusting for the use of conventional sternotomy (CS) and minimally invasive left thoracotomy (MILT) was performed. Univariate analysis revealed a 65% reduction in re-exploration (43–15%, p < 0.001), and an 82% reduction in delayed sternal closure (DSC; 34–6%, p <0.001). In a sub-analysis of CS only, there continued to be statistically significant 53% reduction in re-exploration (45% vs. 21%, p = 0.0011), and a 77% reduction in DSC (35% vs. 8%, p < 0.001) in group 2. Using a logistic regression model adjusting for CS versus MILT, there was a significant reduction in re-exploration (odds ratio [OR] = 0.44 [confidence interval {CI} = 0.23–0.85], p = 0.014) and DSC (OR = 0.20 [CI = 0.08–0.46], p <0.001) in group 2. Actively maintaining chest tube patency after LVAD implantation significantly reduces re-exploration and DSC. PMID:27556153

  10. Novel windows for "solar commodities": a device for CO2 reduction using plasmonic catalyst activation.

    PubMed

    Navarrete, Alexander; Muñoz, Sergio; Sanz-Moral, Luis M; Brandner, Juergen J; Pfeifer, Peter; Martín, Ángel; Dittmeyer, Roland; Cocero, María J

    2015-01-01

    A novel plasmonic reactor concept is proposed and tested to work as a visible energy harvesting device while allowing reactions to transform CO2 to be carried out. Particularly the reverse water gas shift (RWGS) reaction has been tested as a means to introduce renewable energy into the economy. The development of the new reactor concept involved the synthesis of a new composite capable of plasmonic activation with light, the development of an impregnation method to create a single catalyst reactor entity, and finally the assembly of a reaction system to test the reaction. The composite developed was based on a Cu/ZnO catalyst dispersed into transparent aerogels. This allows efficient light transmission and a high surface area for the catalyst. An effective yet simple impregnation method was developed that allowed introduction of the composites into glass microchannels. The activation of the reaction was made using LEDs that covered all the sides of the reactor allowing a high power delivery. The results of the reaction show a stable process capable of low temperature transformations.

  11. A glasses-type wearable device for monitoring the patterns of food intake and facial activity

    NASA Astrophysics Data System (ADS)

    Chung, Jungman; Chung, Jungmin; Oh, Wonjun; Yoo, Yongkyu; Lee, Won Gu; Bang, Hyunwoo

    2017-01-01

    Here we present a new method for automatic and objective monitoring of ingestive behaviors in comparison with other facial activities through load cells embedded in a pair of glasses, named GlasSense. Typically, activated by subtle contraction and relaxation of a temporalis muscle, there is a cyclic movement of the temporomandibular joint during mastication. However, such muscular signals are, in general, too weak to sense without amplification or an electromyographic analysis. To detect these oscillatory facial signals without any use of obtrusive device, we incorporated a load cell into each hinge which was used as a lever mechanism on both sides of the glasses. Thus, the signal measured at the load cells can detect the force amplified mechanically by the hinge. We demonstrated a proof-of-concept validation of the amplification by differentiating the force signals between the hinge and the temple. A pattern recognition was applied to extract statistical features and classify featured behavioral patterns, such as natural head movement, chewing, talking, and wink. The overall results showed that the average F1 score of the classification was about 94.0% and the accuracy above 89%. We believe this approach will be helpful for designing a non-intrusive and un-obtrusive eyewear-based ingestive behavior monitoring system.

  12. Stability of cooled beams

    NASA Astrophysics Data System (ADS)

    Bosser, J.; Carli, C.; Chanel, M.; Madsen, N.; Maury, S.; Möhl, D.; Tranquille, G.

    2000-02-01

    Because of their high density together with extremely small spreads in betatron frequency and momentum, cooled beams are very vulnerable to incoherent and coherent space-charge effects and instabilities. Moreover, the cooling system itself, i.e. the electron beam in the case of e-cooling, presents large linear and non-linear "impedances" to the circulating ion beam, in addition to the usual beam-environment coupling impedances of the storage ring. Beam blow-up and losses, attributed to such effects, have been observed in virtually all the existing electron cooling rings. The adverse effects seem to be more pronounced in those rings, like CELSIUS, that are equipped with a cooler capable of reaching the presently highest energy (100-300 keV electrons corresponding to 180-560 MeV protons). The stability conditions will be revisited with emphasis on the experience gained at LEAR. It will be argued that for all present coolers, three conditions are necessary (although probably not sufficient) for the stability of intense cold beams: (i) operation below transition energy, (ii) active damping to counteract coherent instability, and (iii) careful control of the e-beam neutralisation. An extrapolation to the future "medium energy coolers", planned to work for (anti)protons of several GeV, will also be attempted.

  13. Jumping-droplet electronics hot-spot cooling

    DOE PAGES

    Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; ...

    2017-03-20

    Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm x 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobicmore » surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25°C air temperature, 20-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm), and heat flux (demonstrated to 13 W/cm2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈ 200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm2. Finally, this work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.« less

  14. The integration of cryogenic cooling systems with superconducting electronic systems

    SciTech Connect

    Green, Michael A.

    2003-07-01

    The need for cryogenic cooling has been critical issue that has kept superconducting electronic devices from reaching the market place. Even though the performance of the superconducting circuit is superior to silicon electronics, the requirement for cryogenic cooling has put the superconducting devices at a disadvantage. This report will talk about the various methods for refrigerating superconducting devices. Cryocooler types will be compared for vibration, efficiency, and cost. Some solutions to specific problems of integrating cryocoolers to superconducting devices are presented.

  15. Sensitive monitoring of photocarrier densities in the active layer of a photovoltaic device with time-resolved terahertz reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Yamashita, Genki; Matsubara, Eiichi; Nagai, Masaya; Kim, Changsu; Akiyama, Hidefumi; Kanemitsu, Yoshihiko; Ashida, Masaaki

    2017-02-01

    We demonstrate the sensitive measurement of photocarriers in an active layer of a GaAs-based photovoltaic device using time-resolved terahertz reflection spectroscopy. We found that the reflection dip caused by Fabry-Pérot interference is strongly affected by the carrier profile in the active layer of the p-i-n structure. The experimental results show that this method is suitable for quantitative evaluation of carrier dynamics in active layers of solar cells under operating conditions.

  16. EVALUATION OF PERSONAL COOLING DEVICES FOR A ...

    EPA Pesticide Factsheets

    The study investigated the use of personal coolers to increase worker productivity and safety while working at elevated, ambient temperatures cleaning up dioxin contaminated soil.^The study included laboratory tests to measure the thermal characteristics of the chemical protective clothing worn and the performance of ice vest and vortex personal coolers.^In addition, field tests were conducted at a dioxin clean-up site to evaluate the performance of these two types of personal coolers.^The use of personal coolers was found to be an effective method of reducing the risk of heat stress.^In addition, workers were able to work continuously in hot weather without following the procedure normally used to decrease heat stress, i.e., working one hour followed by one hour of resting.^Both types of personal coolers were acceptable for the task being performed. information

  17. Ag5IO6: novel antibiofilm activity of a silver compound with application to medical devices.

    PubMed

    Incani, Vanessa; Omar, Amin; Prosperi-Porta, Graeme; Nadworny, Patricia

    2015-06-01

    This work explores the unique antibiofilm activity of pentasilver hexaoxoiodate (Ag(5)IO(6)). To test this activity, wound dressings were impregnated with Ag(5)IO(6) and compared with various commercially available silver-containing dressings, as well as dressings containing chlorhexidine, iodine and polyhexamethylene biguanide (PHMB). The materials were tested against Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans for their ability to prevent micro-organism adherence, eliminate planktonic micro-organisms and disrupt/eliminate mature biofilms generated using the MBEC™ assay within 24 h of microbial exposure. Only the Ag(5)IO(6)-containing dressings were able to prevent adherence and eliminate surrounding planktonic micro-organisms for all species tested for ≥28 days of elution with log reductions >4. Two other silver dressings succeeded against P. aeruginosa only after 28 elution days, whilst the PHMB dressing succeeded after 28 days of elution against C. albicans only. Ag(5)IO(6)-containing dressings were able to generate >4 log reductions against all biofilms tested. The only commercial dressings able to generate >4 log reductions against biofilms were iodine against P. aeruginosa and S. aureus, and PHMB against S. aureus. The Ag(5)IO(6) dressings demonstrated complete kill (>4 log reduction) in a standard 30-min planktonic log reduction assay against all species. These results demonstrate that Ag(5)IO(6) has superior activity to a number of antimicrobials, with broad-spectrum efficacy that includes long-term prevention of microbial adherence, rapid kill of planktonic micro-organisms, and the ability to disrupt and eliminate mature biofilms. Thus, Ag(5)IO(6) may be a valuable antimicrobial agent for use in a number of medical device applications, including wound dressings, various catheters or implants.

  18. Bistable laser device with multiple coupled active vertical-cavity resonators

    DOEpatents

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-08-19

    A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.

  19. Water cooled silicon crystals for X-ray monochromators

    NASA Astrophysics Data System (ADS)

    Wahl, R.; Shah, R.; Jackson, K.; Tonnessen, T.

    1992-07-01

    Insertion devices (wigglers and undulators) proposed for synchrotron radiation sources will produce up to 10 kW/cm2 of thermal loading. In a double crystal monochromator, the first crystal must absorb nearly all of this output power, as it diffracts the desired wavelength to the second crystal. Storage rings currently projected or under construction produce heat loads of this intensity and thus require significantly improved optical element cooling methods to preserve the spectral quality of the output radiation. As beam intensities reach these higher levels, analysis of the thermal performance of passive and actively cooled optical elements becomes more and more critical because such elements are a cost effective means for producing a cooled crystal that performs to its design specifications the first time it is installed in the beamline. The Rocketdyne Division of Rockwell International is applying the experience gained in high energy laser optics research (the design of cooled IR and UV optical components for free electron lasers) to the problems of cooled X-ray monochromator crystals and grazing incidence VUV optics. In this paper, a set of first order parametric calculations and a second order finite element calculation were performed to determine surface temperature rise, coolant pressure drop and surface distortion in a single crystal silicon heat exchanger with heat loads of 100 to 550 W/cm2. Two different heat exchanger designs (microchannels and pin post cell) and two different coolants (water and liquid gallium) were analyzed to assess performance advantages of each.

  20. Current Pulses Momentarily Enhance Thermoelectric Cooling

    NASA Technical Reports Server (NTRS)

    Snyder, G. Jeffrey; Fleurial, Jean-Pierre; Caillat, Thierry; Chen, Gang; Yang, Rong Gui

    2004-01-01

    The rates of cooling afforded by thermoelectric (Peltier) devices can be increased for short times by applying pulses of electric current greater than the currents that yield maximum steady-state cooling. It has been proposed to utilize such momentary enhancements of cooling in applications in which diode lasers and other semiconductor devices are required to operate for times of the order of milliseconds at temperatures too low to be easily obtainable in the steady state. In a typical contemplated application, a semiconductor device would be in contact with the final (coldest) somewhat taller stage of a multistage thermoelectric cooler. Steady current would be applied to the stages to produce steady cooling. Pulsed current would then be applied, enhancing the cooling of the top stage momentarily. The principles of operation are straightforward: In a thermoelectric device, the cooling occurs only at a junction at one end of the thermoelectric legs, at a rate proportional to the applied current. However, Joule heating occurs throughout the device at a rate proportional to the current squared. Hence, in the steady state, the steady temperature difference that the device can sustain increases with current only to the point beyond which the Joule heating dominates. If a pulse of current greater than the optimum current (the current for maximum steady cooling) is applied, then the junction becomes momentarily cooled below its lowest steady temperature until thermal conduction brings the resulting pulse of Joule heat to the junction and thereby heats the junction above its lowest steady temperature. A theoretical and experimental study of such transient thermoelectric cooling followed by transient Joule heating in response to current pulses has been performed. The figure presents results from one of the experiments. The study established the essential parameters that characterize the pulse cooling effect, including the minimum temperature achieved, the maximum