WorldWideScience

Sample records for operating temperature determination

  1. Operating Cell Temperature Determination in Flat-Plate Photovoltaic Modules; Calculo de la Temperature de Operacion de Celulas Solares en un Panel Fotovoltaico Plano

    Energy Technology Data Exchange (ETDEWEB)

    Chenlo, F.

    2002-07-01

    Two procedures (simplified and complete) to determine the operating cell temperature in photovoltaic modules operating in real conditions assuming isothermal stationary modules are presented in this work. Some examples are included that show the dependence of this temperature on several environment (sky, ground and ambient temperatures, solar irradiance, wind speed, etc.) and structural (module geometry and size, encapsulating materials, antirreflexive optical coatings, etc) factors and also on electrical module performance. In a further step temperature profiles for non-isothermal modules are analysed besides transitory effects due to variable irradiance and wind gusts. (Author)

  2. Detailed analysis of an endoreversible fuel cell : Maximum power and optimal operating temperature determination

    CERN Document Server

    Vaudrey, A; Lanzetta, F; Glises, R

    2009-01-01

    Producing useful electrical work in consuming chemical energy, the fuel cell have to reject heat to its surrounding. However, as it occurs for any other type of engine, this thermal energy cannot be exchanged in an isothermal way in finite time through finite areas. As it was already done for various types of systems, we study the fuel cell within the finite time thermodynamics framework and define an endoreversible fuel cell. Considering different types of heat transfer laws, we obtain an optimal value of the operating temperature, corresponding to a maximum produced power. This analysis is a first step of a thermodynamical approach of design of thermal management devices, taking into account performances of the whole system.

  3. Cable historical operating temperature estimator

    Energy Technology Data Exchange (ETDEWEB)

    Leon de, F.; St-Roch, P.; Beauregard, C. [Cyme International, St-Bruno, PQ (Canada)

    2006-07-01

    A tool designed to accurately determine the thermal age of underground cables was described. The cable historical operating temperature estimate (CHOTE) is a software application designed to identify which cables have exceeded their normal and emergency operating temperatures. CHOTE is also capable of predicting when cables are likely to reach their maximum design temperature in the future. The system operates by processing archived loading information from data acquisition systems in order to automatically analyze all the thermal sections of a system. Cables that exceed their emergency and normal temperatures for the longest amount of time are ranked first, and outputs display when and where the hot spots have occurred. CHOTE is also able to study the impact of the addition of new cables and to determine the remaining ampacity of cables installed in a given duct bank. It was concluded that the CHOTE system can help in the efficient management of cable repairs and installations. 28 refs., 7 figs.

  4. RPC operation at high temperature

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Stante, L; Liberti, B; Paoloni, A; Pastori, E; Santonico, R

    2003-01-01

    The resistive electrodes of RPCs utilised in several current experiments (ATLAS, CMS, ALICE, BABAR and ARGO) are made of phenolic /melaminic polymers, with room temperature resistivities ranging from 10**1**0 Omega cm, for high rate operation in avalanche mode, to 5 multiplied by 10**1**1 Omega cm, for streamer mode operation at low rate. The resistivity has however a strong temperature dependence, decreasing exponentially with increasing temperature. We have tested several RPCs with different electrode resistivities in avalanche as well as in streamer mode operation. The behaviours of the operating current and of the counting rate have been studied at different temperatures. Long-term operation has also been studied at T = 45 degree C and 35 degree C, respectively, for high and low resistivity electrodes RPCs.

  5. Determining Outdoor CPV Cell Temperature (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Muller, M.

    2011-04-01

    An accurate method is needed for determining cell temperature when measuring CPV modules outdoors. It has been suggested that cell temperature can be calculated though a procedure that shutters sunlight to the cells while measuring the transients in open-circuit voltage (Voc) and heat sink temperature. This presentation documents application of this shutter procedure to multiple CPV modules at NREL. The challenges and limitations are presented along with an alternate approach to measuring CPV cell operating temperature.

  6. Temperature buffer test. Dismantling operation

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

    2010-12-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

  7. Temperature buffer test. Dismantling operation

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias [Clay Technology AB, Lund (Sweden)

    2010-12-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modelling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aespoe HRL. It was installed during the spring of 2003. Two heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by bentonite in the usual way, whereas the upper heater was surrounded by a ring of sand. The test was dismantled and sampled during a period from the end of October 2009 to the end of April 2010, and this report describes this operation. Different types of samples have been obtained during this operation. A large number of diameter 50 mm bentonite cores have been taken for analysis of water content and density. Large pieces, so-called big sectors, have been taken for hydro-mechanical and chemical characterizations. Finally, there has been an interest to obtain different types of interface samples in which bentonite were in contact with sand, iron or concrete. One goal has been to investigate the retrievability of the upper heater, given the possibility to remove the surrounding sand shield, and a retrieval test has therefore been performed. The sand in the shield was first removed with an industrial vacuum cleaner after loosening the material through mechanical means (with hammer drill and core machine). A front loader was subsequently used for applying a sufficient lifting force to release the heater from the bentonite underneath. The experiment has been documented in different aspects: measurements of the coordinate (height or radius) of different interfaces (between bentonite blocks and between bentonite and sand); verification of sensor positions and retrieval of sensors for subsequent

  8. Numerical method for determining the allowable medium temperature during transient operation of a thick-walled boiler element in power plant

    Science.gov (United States)

    Rząsa, Dariusz; Duda, Piotr

    2011-12-01

    Secure and cost-effective power generation has become very important nowdays. Care must be taken while designing and operating modern steam power plants. There are regulations such as German boiler regulations (Technische Regeln für Dampfkessel 301) or European Standards that guide the user how to operate the steam power plants. However, those regulations are based on the quasi-steady state assumption and one dimensional temperature distribution in the entire element. This simplifications may not guarantee that the heating and cooling operations are conducted in the most efficient way. Thus, it was important to find an improved method that can allow to establish optimum parameters for heating and cooling operations. The optimum parameters should guarantee that the maximum total stresses in the construction element are in the allowable limits and the entire process is conducted in the shortest time. This paper summarizes mathematical descriptions how to optimize shut down process of power block devices. The optimization formulation is based on the assumption that the maximum total stresses in the whole construction element should be kept within allowable limits during cooling operation. Additionally, the operation should be processed in the shortest time possible.

  9. Thermal Operator Representation of Finite Temperature Graphs

    OpenAIRE

    Brandt, Fernando T.; Das, Ashok; Espinosa, Olivier; Frenkel, Josif; Perez, Silvana

    2005-01-01

    Using the mixed space representation (t,p) in the context of scalar field theories, we prove in a simple manner that the Feynman graphs at finite temperature are related to the corresponding zero temperature diagrams through a simple thermal operator, both in the imaginary time as well as in the real time formalisms. This result is generalized to the case when there is a nontrivial chemical potential present. Several interesting properties of the thermal operator are also discussed.

  10. Simple operated multipurpose temperature control cryostat

    Institute of Scientific and Technical Information of China (English)

    ABBAS T.A.; OMAR M.S.

    2007-01-01

    A suitable simple optical cryostat for optical, magneto-optical, electrical and thermo-electrical measurements was designed. It is suitable for use in a magnetic pool gap as narrow as less than 1 cm. Throughout a long period of time, the heat diffusion process of the cryostat can be easily operated at slow increase in sample temperature in a range 1.25 K/min at 200 K that will be reduced gradually to 0.66 K at room temperature. Liquid nitrogen was used to cool down the temperature. During the operation, the change in the measured energy gap of a semiconductor sample and other physical parameters resulting from the change of temperature can be corrected through the temperature coefficient of that parameter at the corresponding temperature.The cryostat was successfully used for all experiments mentioned above to measure the properties of a single crystal of GaP (Gallium Phosphate) semiconductor.

  11. Electronics Demonstrated for Low- Temperature Operation

    Science.gov (United States)

    Patterson, Richard L.; Hammond, Ahmad; Gerber, Scott S.

    2000-01-01

    The operation of electronic systems at cryogenic temperatures is anticipated for many NASA spacecraft, such as planetary explorers and deep space probes. For example, an unheated interplanetary probe launched to explore the rings of Saturn would experience an average temperature near Saturn of about 183 C. Electronics capable of low-temperature operation in the harsh deep space environment also would help improve circuit performance, increase system efficiency, and reduce payload development and launch costs. An ongoing research and development program on low-temperature electronics at the NASA Glenn Research Center at Lewis Field is focusing on the design of efficient power systems that can survive and exploit the advantages of low-temperature environments. The targeted systems, which are mission driven, include converters, inverters, controls, digital circuits, and special-purpose circuits. Initial development efforts successfully demonstrated the low-temperature operation and cold-restart of several direct-current/direct-current (dc/dc) converters based on different types of circuit design, some with superconducting inductors. The table lists some of these dc/dc converters with their properties, and the photograph shows a high-voltage, high-power dc/dc converter designed for an ion propulsion system for low-temperature operation. The development efforts of advanced electronic systems and the supporting technologies for low-temperature operation are being carried out in-house and through collaboration with other Government agencies, industry, and academia. The Low Temperature Electronics Program supports missions and development programs at NASA s Jet Propulsion Laboratory and Goddard Space Flight Center. The developed technologies will be transferred to commercial end users for applications such as satellite infrared sensors and medical diagnostic equipment.

  12. Low temperature operation and exhaust emission

    Energy Technology Data Exchange (ETDEWEB)

    Laurikko, J.

    1987-01-01

    Ambient temperature has the greatest effect on the exhaust emissions of internal combustion engines during the initial cold star and before the engine is fully warmed-up. Fuel evaporation is poor in a cold engine and the fuel-air mixture must be made richer to ensure that the engine weill start and be driveable. However, the combustion of a rich fuel-air mixture is incomplete because of the lack of oxygen, and the exhaust gases will contain an excessive amount of carbon monoxide (CO). The formation of nitrogen oxides (NO/sub x/) in a combustion engine is tied to high temperatures and oxygen concentrations. The conditions in a non-warmed engine using a rich fuel-air mixture are unfavourable for the formation of NO/sub x/ and the emission of NO/sub x/ may even diminish with falling ambient temperature. When the engine has reached its normal operating temperature the exhaust emissions are usually independent of the ambient temperature if the engine is equipped with intake air preheating that is sufficiently powerful. The reduction efficiency of a catalytic converter mainly depends on its operation temperature. Continuous operation at low temperatures may cause rapid poisoning of the converter. At low temperatures, carbon and other particles that do not burn collect on the active surface of the converter reducing its effectiveness.

  13. Operator product expansion at finite temperature

    OpenAIRE

    Mallik, S.

    1997-01-01

    We extend an earlier, configuration space method to find the Wilson coefficients of operators appearing in the short distance expansion of thermal correlation functions of different quark bilinears. Considering all the different correlation functions, there arise, up to dimension four, two new operators, in addition to the two appearing already in the vacuum correlation functions. They would contribute substantially to the QCD sum rules, when the temperature is not too low.

  14. Wide-Temperature-Range Integrated Operational Amplifier

    Science.gov (United States)

    Mojarradi, Mohammad; Levanas, Greg; Chen, Yuan; Kolawa, Elizabeth; Cozy, Raymond; Blalock, Benjamin; Greenwell, Robert; Terry, Stephen

    2007-01-01

    A document discusses a silicon-on-insulator (SOI) complementary metal oxide/semiconductor (CMOS) integrated- circuit operational amplifier to be replicated and incorporated into sensor and actuator systems of Mars-explorer robots. This amplifier is designed to function at a supply potential less than or equal to 5.5 V, at any temperature from -180 to +120 C. The design is implemented on a commercial radiation-hard SOI CMOS process rated for a supply potential of less than or equal to 3.6 V and temperatures from -55 to +110 C. The design incorporates several innovations to achieve this, the main ones being the following: NMOS transistor channel lengths below 1 m are generally not used because research showed that this change could reduce the adverse effect of hot carrier injection on the lifetimes of transistors at low temperatures. To enable the amplifier to withstand the 5.5-V supply potential, a circuit topology including cascade devices, clamping devices, and dynamic voltage biasing was adopted so that no individual transistor would be exposed to more than 3.6 V. To minimize undesired variations in performance over the temperature range, the transistors in the amplifier are biased by circuitry that maintains a constant inversion coefficient over the temperature range.

  15. 33 CFR 159.119 - Operability test; temperature range.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Operability test; temperature range. 159.119 Section 159.119 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with...

  16. Membrane Transition Temperature Determines Cisplatin Response.

    Directory of Open Access Journals (Sweden)

    Krishnan Raghunathan

    Full Text Available Cisplatin is a classical chemotherapeutic agent used in treating several forms of cancer including head and neck. However, cells develop resistance to the drug in some patients through a range of mechanisms, some of which are poorly understood. Using isolated plasma membrane vesicles as a model system, we present evidence suggesting that cisplatin induced resistance may be due to certain changes in the bio-physical properties of plasma membranes. Giant plasma membrane vesicles (GPMVs isolated from cortical cytoskeleton exhibit a miscibility transition between a single liquid phase at high temperature and two distinct coexisting liquid phases at low temperature. The temperature at which this transition occurs is hypothesized to reflect the magnitude of membrane heterogeneity at physiological temperature. We find that addition of cisplatin to vesicles isolated from cisplatin-sensitive cells result in a lowering of this miscibility transition temperature, whereas in cisplatin-resistant cells such treatment does not affect the transition temperature. To explore if this is a cause or consequence of cisplatin resistance, we tested if addition of cisplatin in combination with agents that modulate GPMV transition temperatures can affect cisplatin sensitivity. We found that cells become more sensitive to cisplatin when isopropanol, an agent that lowers GPMV transition temperature, was combined with cisplatin. Conversely, cells became resistant to cisplatin when added in combination with menthol that raises GPMV transition temperatures. These data suggest that changes in plasma membrane heterogeneity augments or suppresses signaling events initiated in the plasma membranes that can determine response to cisplatin. We postulate that desired perturbations of membrane heterogeneity could provide an effective therapeutic strategy to overcome cisplatin resistance for certain patients.

  17. Wide-temperature integrated operational amplifier

    Science.gov (United States)

    Mojarradi, Mohammad (Inventor); Levanas, Greg (Inventor); Chen, Yuan (Inventor); Cozy, Raymond S. (Inventor); Greenwell, Robert (Inventor); Terry, Stephen (Inventor); Blalock, Benjamin J. (Inventor)

    2009-01-01

    The present invention relates to a reference current circuit. The reference circuit comprises a low-level current bias circuit, a voltage proportional-to-absolute temperature generator for creating a proportional-to-absolute temperature voltage (VPTAT), and a MOSFET-based constant-IC regulator circuit. The MOSFET-based constant-IC regulator circuit includes a constant-IC input and constant-IC output. The constant-IC input is electrically connected with the VPTAT generator such that the voltage proportional-to-absolute temperature is the input into the constant-IC regulator circuit. Thus the constant-IC output maintains the constant-IC ratio across any temperature range.

  18. Temperature tides determined with meteor radar

    Science.gov (United States)

    Hocking, W. K.; Hocking, A.

    2002-09-01

    A new analysis method for producing tidal temperature parameters using meteor radar measurements is presented, and is demonstrated with data from one polar and two mid-latitude sites. The technique further develops the temperature algorithm originally introduced by Hocking (1999). That earlier method was used to produce temperature measurements over time scales of days and months, but required an empirical model for the mean temperature gradient in the mesopause region. However, when tides are present, this temperature gradient is modulated by the presence of the tides, complicating extraction of diurnal variations. Nevertheless, if the vertical wavelengths of the tides are known from wind measurements, the effects of the gradient variations can be compensated for, permitting determination of temperature tidal amplitudes and phases by meteor techniques. The basic theory is described, and results from meteor radars at Resolute Bay (Canada), London (Canada) and Albuquerque (New Mexico, USA) are shown. Our results are compared with other lidar data, computer models, fundamental tidal theory and rocket data. Phase measurements at two mid-latitude sites (Albuquerque, New Mexico, and London, Canada) show times of maximum for the diurnal temperature tide to change modestly throughout most of the year, varying generally between 0 h and 6 h, with an excursion to 12 h in June at London. The semidiurnal tide shows a larger annual variation in time of maximum, being at 2 4 h in the winter months but increasing to 9 h during the late summer and early fall. We also find that, at least at mid-latitudes, the phase of the temperature tide matches closely the phase of the meridional tide, and theoretical justification for this statement is given. We also demonstrate that this is true using the Global Scale Wave Model (Hagan et al., 1999). Median values for the temperature amplitudes for each site are in the range 5 to 6 Kelvin. Results from a more northern site (Resolute Bay) show

  19. Test plans of the high temperature test operation at HTTR

    Energy Technology Data Exchange (ETDEWEB)

    Sakaba, Nariaki; Nakagawa, Shigeaki; Takada, Eiji [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment] [and others

    2003-03-01

    HTTR plans a high temperature test operation as the fifth step of the rise-to-power tests to achieve a reactor outlet coolant temperature of 950 degrees centigrade in the 2003 fiscal year. Since HTTR is the first HTGR in Japan which uses coated particle fuel as its fuel and helium gas as its coolant, it is necessary that the plan of the high temperature test operation is based on the previous rise-to-power tests with a thermal power of 30 MW and a reactor outlet coolant temperature at 850 degrees centigrade. During the high temperature test operation, reactor characteristics, reactor performances and reactor operations are confirmed for the safety and stability of operations. This report describes the evaluation result of the safety confirmations of the fuel, the control rods and the intermediate heat exchanger for the high temperature test operation. Also, problems which were identified during the previous operations are shown with their solution methods. Additionally, there is a discussion on the contents of the high temperature test operation. As a result of this study, it is shown that the HTTR can safely achieve a thermal power of 30 MW with the reactor outlet coolant temperature at 950 degrees centigrade. (author)

  20. CFB cyclones at high temperature: Operational results and design assessment

    Institute of Scientific and Technical Information of China (English)

    Raf Dewil; Jan Baeyens; Bart Caerts

    2008-01-01

    Pressure drop and cut size measurements are reported for a full scale cyclone operating within a 58 MWth CFB-combustor unit at 775℃.The paper reviews the vast number of equations to calculate the pressure drop and separation efficiency of cyclones, generally for operation at ambient temperature and at low Cs[0.5]. None of the literature correlations predicts the pressure drop with a fair accuracy within the range of experimental operating conditions. The cut size d50 can be estimated using direct empirical methods or using the Stokes number, Stk50. Both methods were used to compare measured and predicted values of d50. With the exception of Muschelknautz and Krambrock, none of the equations made accurate predictions.Finally, an alternative method to determine the friction factor of the pressure drop equation (Euler number, Eu) and of the cut size is proposed. The Eu number is determined from the geometry of common cyclones, and the derived value of Stk50 defines more accurate cut sizes. The remaining discrepancy of less than 5%, when compared with the measured values, is tentatively explained in terms of a reduced cyclone diameter due to the solids layer formed near its wall. Further measurements, mostly using positron emission particle tracking, elucidate the particle motion in the cyclone and both tracking results and the influence of the particle movement on Eu and Stk50 will be discussed in a follow-up paper.

  1. Operation of an opamp at liquid helium temperature.

    Science.gov (United States)

    Ng, K.-W.

    1994-02-01

    The stray capacitance between long wires in a cryogenics systems will slow down measurement rate, and also introduce unnecessary noise pick up. It is necessary to install the preamplifier as close to the signal source as possible to diminish the capacitive coupling effects. The most commonly used semiconducting device for this purpose is the MOSFET, which can function at liquid helium temperatures. Under special operation procedures, an all MOSFET operational amplifier can also be operated at liquid helium temperature. The use of opamp will simplify the construction of more complicated circuitry for low temperature applications.

  2. Operational forecasting of daily temperatures in the Valencia Region. Part II: minimum temperatures in winter.

    Science.gov (United States)

    Gómez, I.; Estrela, M.

    2009-09-01

    Extreme temperature events have a great impact on human society. Knowledge of minimum temperatures during winter is very useful for both the general public and organisations whose workers have to operate in the open, e.g. railways, roadways, tourism, etc. Moreover, winter minimum temperatures are considered a parameter of interest and concern since persistent cold-waves can affect areas as diverse as public health, energy consumption, etc. Thus, an accurate forecasting of these temperatures could help to predict cold-wave conditions and permit the implementation of strategies aimed at minimizing the negative effects that low temperatures have on human health. The aim of this work is to evaluate the skill of the RAMS model in determining daily minimum temperatures during winter over the Valencia Region. For this, we have used the real-time configuration of this model currently running at the CEAM Foundation. To carry out the model verification process, we have analysed not only the global behaviour of the model for the whole Valencia Region, but also its behaviour for the individual stations distributed within this area. The study has been performed for the winter forecast period from 1 December 2007 - 31 March 2008. The results obtained are encouraging and indicate a good agreement between the observed and simulated minimum temperatures. Moreover, the model captures quite well the temperatures in the extreme cold episodes. Acknowledgement. This work was supported by "GRACCIE" (CSD2007-00067, Programa Consolider-Ingenio 2010), by the Spanish Ministerio de Educación y Ciencia, contract number CGL2005-03386/CLI, and by the Regional Government of Valencia Conselleria de Sanitat, contract "Simulación de las olas de calor e invasiones de frío y su regionalización en la Comunidad Valenciana" ("Heat wave and cold invasion simulation and their regionalization at Valencia Region"). The CEAM Foundation is supported by the Generalitat Valenciana and BANCAIXA (Valencia

  3. Operational forecasting of daily temperatures in the Valencia Region. Part I: maximum temperatures in summer.

    Science.gov (United States)

    Gómez, I.; Estrela, M.

    2009-09-01

    Extreme temperature events have a great impact on human society. Knowledge of summer maximum temperatures is very useful for both the general public and organisations whose workers have to operate in the open, e.g. railways, roadways, tourism, etc. Moreover, summer maximum daily temperatures are considered a parameter of interest and concern since persistent heat-waves can affect areas as diverse as public health, energy consumption, etc. Thus, an accurate forecasting of these temperatures could help to predict heat-wave conditions and permit the implementation of strategies aimed at minimizing the negative effects that high temperatures have on human health. The aim of this work is to evaluate the skill of the RAMS model in determining daily maximum temperatures during summer over the Valencia Region. For this, we have used the real-time configuration of this model currently running at the CEAM Foundation. To carry out the model verification process, we have analysed not only the global behaviour of the model for the whole Valencia Region, but also its behaviour for the individual stations distributed within this area. The study has been performed for the summer forecast period of 1 June - 30 September, 2007. The results obtained are encouraging and indicate a good agreement between the observed and simulated maximum temperatures. Moreover, the model captures quite well the temperatures in the extreme heat episodes. Acknowledgement. This work was supported by "GRACCIE" (CSD2007-00067, Programa Consolider-Ingenio 2010), by the Spanish Ministerio de Educación y Ciencia, contract number CGL2005-03386/CLI, and by the Regional Government of Valencia Conselleria de Sanitat, contract "Simulación de las olas de calor e invasiones de frío y su regionalización en la Comunidad Valenciana" ("Heat wave and cold invasion simulation and their regionalization at Valencia Region"). The CEAM Foundation is supported by the Generalitat Valenciana and BANCAIXA (Valencia, Spain).

  4. High Operating Temperature, Radiation-Hard MIM Thermophotovoltaic Converters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spire Corporation proposes to investigate InGaAs thermophotovoltaic (TPV) cells optimized for high temperature operation (~150C) and radiation hardness against the...

  5. Extreme High and Low Temperature Operation of the Silicon-On-Insulator Type CHT-OPA Operational Amplifier

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    A new operational amplifier chip based on silicon-on-insulator technology was evaluated for potential use in extreme temperature environments. The CHT-OPA device is a low power, precision operational amplifier with rail-to-rail output swing capability, and it is rated for operation between -55 C and +225 C. A unity gain inverting circuit was constructed utilizing the CHT-OPA chip and a few passive components. The circuit was evaluated in the temperature range from -190 C to +200 C in terms of signal gain and phase shift, and supply current. The investigations were carried out to determine suitability of this device for use in space exploration missions and aeronautic applications under wide temperature incursion. Re-restart capability at extreme temperatures, i.e. power switched on while the device was soaked at extreme temperatures, was also investigated. In addition, the effects of thermal cycling under a wide temperature range on the operation of this high performance amplifier were determined. The results from this work indicate that this silicon-on-insulator amplifier chip maintained very good operation between +200 C and -190 C. The limited thermal cycling had no effect on the performance of the amplifier, and it was able to re-start at both -190 C and +200 C. In addition, no physical degradation or packaging damage was introduced due to either extreme temperature exposure or thermal cycling. The good performance demonstrated by this silicon-on-insulator operational amplifier renders it a potential candidate for use in space exploration missions or other environments under extreme temperatures. Additional and more comprehensive characterization is, however, required to establish the reliability and suitability of such devices for long term use in extreme temperature applications.

  6. Nonlinear Predictive Control for PEMFC Stack Operation Temperature

    Institute of Scientific and Technical Information of China (English)

    LI Xi; CAO Guang-yi; ZHU Xin-jian

    2005-01-01

    Operating temperature of proton exchange membrane fuel cell stack should be controlled within a special range. The input-output data and operating experiences were used to establish a PEMFC stack model and operating temperature control system. A nonlinear predictive control algorithm based on fuzzy model was presented for a family of complex system with severe nonlinearity such as PEMFC. Based on the obtained fuzzy model, a discrete optimization of the control action was carried out according to the principle of Branch and Bound method. The test results demonstrate the effectiveness and advantage of this approach.

  7. Operating temperatures for a convectively cooled recessed incandescent light fixture

    Energy Technology Data Exchange (ETDEWEB)

    Yarbrough, D.W.; Toor, I.

    1980-12-01

    Test results are given for the operation of a recessed incandescent light fixture intended for residential use. The fixture is labeled for use in direct contact with attic thermal insulation. Temperature control of the powered fixture is provided by convective heat transfer from the ceiling side of the fixture. The fixture was operated at power levels up to two times the rated power of 75 watts and under thermal insulations up to R-40. In all operating configurations tested the fixture surface in contact with attic insulation was found to be less than 175/sup 0/C. The observed surface temperatures are judged to be safe for operation in contact with loose-fill or batt-type insulations. It was observed that the power leads inside one fixture configuration are exposed to temperatures as high as 168/sup 0/C. The electrical insulation could, therefore, have a limited life. The properties of the internal fixture wiring were not, however, studied in detail.

  8. Improved Wide Operating Temperature Range of Li-Ion Cells

    Science.gov (United States)

    Smart, Marshall C.; Bugga, Ratnakumar V.

    2013-01-01

    Future NASA missions aimed at exploring the Moon, Mars, and the outer planets require rechargeable batteries that can operate over a wide temperature range (-60 to +60 C) to satisfy the requirements of various applications including landers, rovers, penetrators, CEV, CLV, etc. This work addresses the need for robust rechargeable batteries that can operate well over a wide temperature range. The Department of Energy (DoE) has identified a number of technical barriers associated with the development of Liion rechargeable batteries for PHEVs. For this reason, DoE has interest in the development of advanced electrolytes that will improve performance over a wide range of temperatures, and lead to long life characteristics (5,000 cycles over a 10-year life span). There is also interest in improving the high-voltage stability of these candidate electrolyte systems to enable the operation of up to 5 V with high specific energy cathode materials. Currently, the state-of-the-art lithium-ion system has been demonstrated to operate over a wide range of temperatures (-40 to +40 C); however, the rate capability at the lower temperatures is very poor. In addition, the low-temperature performance typically deteriorates rapidly upon being exposed to high temperatures. A number of electrolyte formulations were developed that incorporate the use of electrolyte additives to improve the high-temperature resilience, low-temperature power capability, and life characteristics of methyl propionate (MP)-based electrolyte solutions. These electrolyte additives include mono-fluoroethylene carbonate (FEC), lithium oxalate, vinylene carbonate (VC), and lithium bis(oxalate borate) (LiBOB), which have previously been shown to result in improved high-temperature resilience of all carbonate-based electrolytes. These MP-based electrolytes with additives have been shown to have improved performance in experiments with MCMB-LiNiCoAlO2 cells.

  9. Extreme operative temperatures are better descriptors of the thermal environment than mean temperatures.

    Science.gov (United States)

    Camacho, Agustín; Trefaut Rodrigues, Miguel; Navas, Carlos

    2015-01-01

    In ecological studies of thermal biology the thermal environment is most frequently described using the mean or other measures of central tendency in environmental temperatures. However, this procedure may hide biologically relevant thermal variation for ectotherms, potentially misleading interpretations. Extremes of operative temperatures (EOT) can help with this problem by bracketing the thermal environment of focal animals. Within this paper, we quantify how mean operative temperatures relate to the range of simultaneously available operative temperatures (a measure of error). We also show how EOT: 1) detect more thermal differences among microsites than measures of central tendency, like the mean OT, 2) allow inferring on microsite use by ectothermic animals, and 3) clarify the relationships between field operative temperatures and temperatures measured at weather stations (WS). To do that, we explored operative temperatures measured at four sites of the Brazilian Caatingas and their correspondent nearest weather stations. We found that the daily mean OT can hide temperature ranges of 41 °C simultaneously available at our study sites. In addition, EOT detected more thermal differences among microsites than central quantiles. We also show how EOT allow inferring about microsite use of ectothermic animals in a given site. Finally, the daily maximum temperature and the daily temperature range measured at WSs predicted well the minimum available field OT at localities many kilometers away. Based on our results, we recommend the use of EOT, instead of mean OT, in thermal ecology studies.

  10. Strategies for Lowering Solid Oxide Fuel Cells Operating Temperature

    Directory of Open Access Journals (Sweden)

    Albert Tarancón

    2009-11-01

    Full Text Available Lowering the operating temperature of solid oxide fuel cells (SOFCs to the intermediate range (500–700 ºC has become one of the main SOFC research goals. High operating temperatures put numerous requirements on materials selection and on secondary units, limiting the commercial development of SOFCs. The present review first focuses on the main effects of reducing the operating temperature in terms of materials stability, thermo-mechanical mismatch, thermal management and efficiency. After a brief survey of the state-of-the-art materials for SOFCs, attention is focused on emerging oxide-ionic conductors with high conductivity in the intermediate range of temperatures with an introductory section on materials technology for reducing the electrolyte thickness. Finally, recent advances in cathode materials based on layered mixed ionic-electronic conductors are highlighted because the decreasing temperature converts the cathode into the major source of electrical losses for the whole SOFC system. It is concluded that the introduction of alternative materials that would enable solid oxide fuel cells to operate in the intermediate range of temperatures would have a major impact on the commercialization of fuel cell technology.

  11. Anodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain

    An important issue that has limited the potential of Solid Oxide Fuel Cells (SOFCs) for portable applications is its high operating temperatures (800-1000 ºC). Lowering the operating temperature of SOFCs to 400-600 ºC enable a wider material selection, reduced degradation and increased lifetime....... On the other hand, low-temperature operation poses serious challenges to the electrode performance. Effective catalysts, redox stable electrodes with improved microstructures are the prime requisite for the development of efficient SOFC anodes. The performance of Nb-doped SrT iO3 (STN) ceramic anodes...... at 400ºC. The potential of using WO3 ceramic as an alternative anode materials has been explored. The relatively high electrode polarization resistance obtained, 11 Ohm cm2 at 600 ºC, proved the inadequate catalytic activity of this system for hydrogen oxidation. At the end of this thesis...

  12. Spectroscopic Methods for Determination of Excitation Temperatures of High-Pressure Plasma

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu; WEN Xiaohui; ZHAN Rujuan; YANG Weihong

    2007-01-01

    A method to determine excitation temperatures based on the optical emission spectroscopy(OES)and Fermi-Dirac distribution was set up,and the temperatures of pure-argon and mixed-gases at different pressures were investigated.In this way we set up a standard process to get the excitation temperatures of plasmas operated at atmospheric and sub-atmospheric pressures.

  13. Empirical Determination of Bang-Bang Operations

    CERN Document Server

    Byrd, M S; Byrd, Mark S.; Lidar, Daniel A.

    2003-01-01

    Strong and fast "bang-bang" (BB) pulses have been recently proposed as a means for reducing decoherence in a quantum system. So far theoretical analysis of the BB technique relied on model Hamiltonians. Here we introduce a method for empirically determining the set of required BB pulses, that relies on quantum process tomography. In this manner an experimenter may tailor his or her BB pulses to the quantum system at hand, without having to assume a model Hamiltonian.

  14. Nylon coil actuator operating temperature range and stiffness

    Science.gov (United States)

    Kianzad, Soheil; Pandit, Milind; Bahi, Addie; Rafie Ravandi, Ali; Ko, Frank; Spinks, Geoffrey M.; Madden, John D. W.

    2015-04-01

    Components in automotive and aerospace applications require a wide temperature range of operation. Newly discovered thermally active Baughman muscle potentially provides affordable and viable solutions for driving mechanical devices by heating them from room temperature, but little is known about their operation below room temperature. We study the mechanical behavior of nylon coil actuators by testing elastic modulus and by investigating tensile stroke as a function of temperature. Loads that range from 35 MPa to 155 MPa were applied. For the nylon used and the coiling conditions, active thermal contraction totals 19.5 % when the temperature is raised from -40 °C to 160 °C. The thermal contraction observed from -40 °C to 20°C is only ~2 %, whereas between 100 and 160 °C the contraction is 10 %. A marked increase in thermal contraction is occurs in the vicinity of the glass transition temperature (~ 45°C). The elastic modulus drops as temperature increases, from ~155 MPa at - 40 °C to 35 MPa at 200 °C. Interestingly the drop in active contraction with increasing load is small and much less than might be expected given the temperature dependence of modulus.

  15. A numerical model for ground temperature determination

    Science.gov (United States)

    Jaszczur, M.; Polepszyc, I.; Biernacka, B.; Sapińska-Śliwa, A.

    2016-09-01

    The ground surface temperature and the temperature with respect to depth are one of the most important issues for geotechnical and environmental applications as well as for plants and other living organisms. In geothermal systems, temperature is directly related to the energy resources in the ground and it influences the efficiency of the ground source system. The ground temperature depends on a very large number of parameters, but it often needs to be evaluated with good accuracy. In the present work, models for the prediction of the ground temperature with a focus on the surface temperature at which all or selected important ground and environmental phenomena are taken into account have been analysed. It has been found that the simplest models and the most complex model may result in a similar temperature variation, yet at a very low depth and for specific cases only. A detailed analysis shows that taking into account different types of pavement or a greater depth requires more complex and advanced models.

  16. Comparison of photovoltaic cell temperatures in modules operating with exposed and enclosed back surfaces

    Science.gov (United States)

    Namkoong, D.; Simon, F. F.

    1981-01-01

    Four different photovoltaic module designs were tested to determine the cell temperature of each design. The cell temperatures were compared to those obtained on identical design, using the same nominal operating cell temperature (NOCT) concept. The results showed that the NOCT procedure does not apply to the enclosed configurations due to continuous transient conditions. The enclosed modules had higher cell temperatures than the open modules, and insulated modules higher than the uninsulated. The severest performance loss - when translated from cell temperatures - 17.5 % for one enclosed, insulated module as a compared to that module mounted openly.

  17. Irradiation dose determination below room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Bernal, S. E-mail: ramos@nuclecu.unam.mx; Cruz, E.; Negron-Mendoza, A.; Bustos, E

    2002-03-01

    The measurements presented were undertaken to provide quantitative information on the low temperature irradiation of thermoluminiscence phosphors. The crystals used were (a) LiF co-doped with Mg, Cu and P, and (b) CaSO{sub 4} doped with Dy. The absorbed dose values in the interval studied showed a linear behavior at low doses and low temperature. The aim of this work is to test if these crystals can be used to measure the dose absorbed by solids at low temperature.

  18. Heating a chemical current source which operates at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Mitsumata, T.; Khosikhara, N.

    1983-02-14

    A chamber for catalytic ignition of hydrogen or gasoline is installed in a chemical current source. The isolated heat heats the chemical current source with a low temperature of the environment providing its optimal operational conditions. The fuel is fed into the chamber from a tank or chamber located in the body of the chemical current source.

  19. 980nm diode laser pump modules operating at high temperature

    Science.gov (United States)

    Campbell, Jenna; Semenic, Tadej; Leisher, Paul; Bhunia, Avijit; Mashanovitch, Milan; Renner, Daniel

    2016-03-01

    Existing thermal management technologies for diode laser pumps place a significant load on the size, weight and power consumption of High Power Solid State and Fiber Laser systems, thus making current laser systems very large, heavy, and inefficient in many important practical applications. This problem is being addressed by the team formed by Freedom Photonics and Teledyne Scientific through the development of novel high power laser chip array architectures that can operate with high efficiency when cooled with coolants at temperatures higher than 50 degrees Celsius and also the development of an advanced thermal management system for efficient heat extraction from the laser chip array. This paper will present experimental results for the optical, electrical and thermal characteristics of 980 nm diode laser pump modules operating effectively with liquid coolant at temperatures above 50 degrees Celsius, showing a very small change in performance as the operating temperature increases from 20 to 50 degrees Celsius. These pump modules can achieve output power of many Watts per array lasing element with an operating Wall-Plug-Efficiency (WPE) of >55% at elevated coolant temperatures. The paper will also discuss the technical approach that has enabled this high level of pump module performance and opportunities for further improvement.

  20. Estimation of operative temperature in buildings using artificial neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Soleimani-Mohseni, M.; Fahlen, P. [Department of Building Services Engineering, Chalmers University of Technology, Goeteborg (Sweden); Thomas, B. [Department of Signals and Systems, Chalmers University of Technology, Campus Lindholmen, Goeteborg (Sweden)

    2006-07-01

    In this article, the problem how to obtain models for estimation of the operative temperature in rooms and buildings is discussed. Identification experiments have been carried out in two different buildings and different linear and non-linear estimation models have been identified based on these experiments. For the buildings studied, it is shown that the operative temperature can be estimated fairly well by using variables, which are more easily measured, such as the indoor and outdoor temperatures, the electrical power use in the room, the wall temperatures, the ventilation flow rates and the time of day. It is also shown that non-linear artificial neural network models (ANN-models), in general, give better estimations than linear ARX-models. The most accurate estimation models were obtained using feed-forward ANN-models with one hidden layer of neurons and using Levenberg-Marquardt's training algorithms. In one of the buildings, it is shown that for non-linear models but not for linear, the estimations are improved much when using the time of day as an input signal. This shows that the time of day affects the operative temperature in a non-linear manner. (author)

  1. THE DETERMINANT REPRESENTATION OF THE GAUGE TRANSFORMATION OPERATORS

    Institute of Scientific and Technical Information of China (English)

    贺劲松; 李翊神; 程艺

    2002-01-01

    The determinant representation of the gauge transformation operators is establised. In this process, the generalized Wronskian determinant is introduced. As a simple application, the auMath. Phys., 149(1992), 263), which involves the generalized Wronskian determinant. Also,some properties of this determinant are given.

  2. Evaluation of Silicon-on-Insulator HTOP-01 Operational Amplifier for Wide Temperature Operation

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Electronics capable of operation under extreme temperatures are required in many of NASA space exploration missions. Aerospace and military applications, as well as some terrestrial industries constitute environments where electronic systems are anticipated to be exposed to extreme temperatures and wide-range thermal swings. Electronics that are able to withstand and operate efficiently in such harsh environments would simplify, if not eliminate, traditional thermal control elements and their associated structures for proper ambient operation. As a result, overall system mass would be reduced, design would be simplified, and reliability would be improved. Electronic parts that are built utilizing silicon-on-insulator (SOI) technology are known to offer better radiation-tolerance compared to their conventional silicon counterparts, provide faster switching, and consume less power. They also exhibit reduced leakage current and, thus, they are often tailored for high temperature operation. These attributes make SOI-based devices suitable for use in harsh environments where extreme temperatures and wide thermal swings are anticipated. A new operational amplifier, based on silicon-on-insulator technology and geared for high temperature well-logging applications, was recently introduced by Honeywell Corporation. This HTOP-01 dual precision operational amplifier is a low power device, operates on a single supply, and has an internal oscillator and an external clocking option [1]. It is rated for operation from -55 C to +225 C with a maximum output current capability of 50 mA. The amplifier chip is designed as a 14-pin, hermetically-sealed device in a ceramic package. Table I shows some of the device manufacturer s specifications.

  3. Determination of Land Surface Temperature (LST) and Potential ...

    African Journals Online (AJOL)

    Determination of Land Surface Temperature (LST) and Potential Urban Heat Island Effect in Parts of Lagos State using Satellite ... Changes in temperature appear to be closely related to concentrations of atmospheric carbon dioxide.

  4. Climate change and temperature-dependent sex determination in reptiles.

    Science.gov (United States)

    Janzen, F J

    1994-08-02

    Despite increasing concern over the possible impact of global temperature change, there is little empirical evidence of direct temperature effects on biotic interactions in natural systems. Clear assessment of the ecological and evolutionary impact of changing climatic temperature requires a natural system in which populations exhibit a direct unambiguous fitness response to thermal fluctuation. I monitored nests of a population of painted turtles (Chrysemys picta) with temperature-dependent sex determination to investigate the causal relationship between local climatic variation in temperature and offspring sex ratio. Consistent with theoretical predictions, annual offspring sex ratio was highly correlated with mean July air temperature, validating concerns about the effect of climate change on population demography. This correlation implies that even modest increases in mean temperature (evolve rapidly enough to counteract the negative fitness consequences of rapid global temperature change. Populations of species with temperature-dependent sex determination may serve as ideal indicators of the biological impact of global temperature change.

  5. Amplifier circuit operable over a wide temperature range

    Science.gov (United States)

    Kelly, Ronald D.; Cannon, William L.

    1979-01-01

    An amplifier circuit having stable performance characteristics over a wide temperature range from approximately 0.degree. C up to as high as approximately 500.degree. C, such as might be encountered in a geothermal borehole. The amplifier utilizes ceramic vacuum tubes connected in directly coupled differential amplifier pairs having a common power supply and a cathode follower output stage. In an alternate embodiment, for operation up to 500.degree. C, positive and negative power supplies are utilized to provide improved gain characteristics, and all electrical connections are made by welding. Resistor elements in this version of the invention are specially heat treated to improve their stability with temperature.

  6. Cathodes for Solid Oxide Fuel Cells Operating at Low Temperatures

    DEFF Research Database (Denmark)

    Samson, Alfred Junio

    This dissertation focuses on the development of nanostructured cathodes for solid oxide fuel cells (SOFCs) and their performance at low operating temperatures. Cathodes were mainly fabricated by the infiltration method, whereby electrocatalysts are introduced onto porous, ionic conducting backbones......degreeC. The most promising cathode was integrated onto an anode supported cell and it was found that the cell exhibits electrochemical stability with no measureable degradation during 1500 h operation at 700degreeC. LaCoO3 and Co3O4 infiltrated - CGO cathodes were also investigated and revealed...

  7. A nonintrusive method for measuring the operating temperature of a solenoid-operated valve

    Science.gov (United States)

    Kryter, Robert C.

    Experimental data are presented to show that the in-service operating temperature of a solenoid operated valve (SOV) can be inferred simply and nondisruptively by using the copper winding of the solenoid coil as a self-indicating, permanently available resistance thermometer. The principal merits of this approach include: (1) there is no need for an add-on temperature sensor, (2) the true temperature of a critical and likely the hottest, part of the SOV (namely, the electrical coil) is measured directly, (3) temperature readout can be provided at any location at which the SOV electrical lead wires are accessible (even though remote from the valve), (4) the SOV need not be disturbed (whether normally energized or deenergized) to measure its temperature in situ, and (5) the method is applicable to all types of SOVs, large and small, ac- and dc-powered. Laboratory tests comparing temperatures measured both by coil resistance and by a conventional thermometer placed in contact with the external surface of the potted solenoid coil indicate that temperature within the coil may be on the order of 40 C higher than that measured externally, a fact that is important to life-expectancy calculations made on the basis of Arrhenius theory. Field practicality is illustrated with temperature measurements made using this method on a SOV controlling the flow of refrigerant in a large chilled-water air-conditioning system.

  8. Effect of operating microscope light on brain temperature during craniotomy.

    Science.gov (United States)

    Gayatri, Parthasarathi; Menon, Girish G; Suneel, Puthuvassery R

    2013-07-01

    Operating microscopes used during neurosurgery are fitted with xenon light. Burn injuries have been reported because of xenon microscope lighting as the intensity of xenon light is 300 W. We designed this study to find out if the light of operating microscope causes an increase in temperature of the brain tissue, which is exposed underneath. Twenty-one adult patients scheduled for elective craniotomies were enrolled. Distal esophageal temperature (T Eso), brain temperature under the microscope light (T Brain), and brain temperature under dura mater (T Dura) were measured continuously at 15-minute intervals during microscope use. The irrigation fluid temperature, room temperature, intensity of the microscope light, and the distance of the microscope from the brain surface were kept constant. The average age of the patients was 44±15 years (18 males and 3 females). The mean duration of microscope use was 140±39 minutes. There were no significant changes in T Brain and T Dura and T Eso over time. T Dura was significantly lower than T Brain both at time 0 and 60 minutes but not at 90 minutes. T Brain was significantly lower than T Eso both at time 0 and 60 minutes but not at 90 minutes. The T Dura remained significantly lower than T Eso at 0, 60, and 90 minutes. Our study shows that there is no significant rise in brain temperature under xenon microscope light up to 120 minutes duration, at intensity of 60% to 70%, from a distance of 20 to 25 cm from the brain surface.

  9. Performance of High Temperature Operational Amplifier, Type LM2904WH, under Extreme Temperatures

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Operation of electronic parts and circuits under extreme temperatures is anticipated in NASA space exploration missions as well as terrestrial applications. Exposure of electronics to extreme temperatures and wide-range thermal swings greatly affects their performance via induced changes in the semiconductor material properties, packaging and interconnects, or due to incompatibility issues between interfaces that result from thermal expansion/contraction mismatch. Electronics that are designed to withstand operation and perform efficiently in extreme temperatures would mitigate risks for failure due to thermal stresses and, therefore, improve system reliability. In addition, they contribute to reducing system size and weight, simplifying its design, and reducing development cost through the elimination of otherwise required thermal control elements for proper ambient operation. A large DC voltage gain (100 dB) operational amplifier with a maximum junction temperature of 150 C was recently introduced by STMicroelectronics [1]. This LM2904WH chip comes in a plastic package and is designed specifically for automotive and industrial control systems. It operates from a single power supply over a wide range of voltages, and it consists of two independent, high gain, internally frequency compensated operational amplifiers. Table I shows some of the device manufacturer s specifications.

  10. NGNP/HTE full-power operation at reduced high-temperature heat exchanger temperatures.

    Energy Technology Data Exchange (ETDEWEB)

    VIlim, R.; Nuclear Engineering Division

    2009-03-12

    Operation of the Next Generation Nuclear Plant (NGNP) with reduced reactor outlet temperature at full power was investigated for the High Temperature Electrolysis (HTE) hydrogen-production application. The foremost challenge for operation at design temperature is achieving an acceptably long service life for heat exchangers. In both the Intermediate Heat Exchanger (IHX) and the Process Heat Exchanger (PHX) (referred to collectively as high temperature heat exchangers) a pressure differential of several MPa exists with temperatures at or above 850 C. Thermal creep of the heat exchanger channel wall may severely limit heat exchanger life depending on the alloy selected. This report investigates plant performance with IHX temperatures reduced by lowering reactor outlet temperature. The objective is to lower the temperature in heat transfer channels to the point where existing materials can meet the 40 year lifetime needed for this component. A conservative estimate for this temperature is believed to be about 700 C. The reactor outlet temperature was reduced from 850 C to 700 C while maintaining reactor power at 600 MWt and high pressure compressor outlet at 7 MPa. We included a previously reported design option for reducing temperature at the PHX. Heat exchanger lengths were adjusted to reflect the change in performance resulting from coolant property changes and from resizing related to operating-point change. Turbomachine parameters were also optimized for the new operating condition. An integrated optimization of the complete system including heat transfer equipment was not performed. It is estimated, however, that by performing a pinch analysis the combined plant efficiency can be increased from 35.5 percent obtained in this report to a value between 38.5 and 40.1 percent. Then after normalizing for a more than three percent decrease in commodities inventory compared to the reference plant, the commodities-normalized efficiency lies between 40.0 and 41.3. This

  11. Temperature mapping of operating nanoscale devices by scanning probe thermometry

    Science.gov (United States)

    Menges, Fabian; Mensch, Philipp; Schmid, Heinz; Riel, Heike; Stemmer, Andreas; Gotsmann, Bernd

    2016-03-01

    Imaging temperature fields at the nanoscale is a central challenge in various areas of science and technology. Nanoscopic hotspots, such as those observed in integrated circuits or plasmonic nanostructures, can be used to modify the local properties of matter, govern physical processes, activate chemical reactions and trigger biological mechanisms in living organisms. The development of high-resolution thermometry techniques is essential for understanding local thermal non-equilibrium processes during the operation of numerous nanoscale devices. Here we present a technique to map temperature fields using a scanning thermal microscope. Our method permits the elimination of tip-sample contact-related artefacts, a major hurdle that so far has limited the use of scanning probe microscopy for nanoscale thermometry. We map local Peltier effects at the metal-semiconductor contacts to an indium arsenide nanowire and self-heating of a metal interconnect with 7 mK and sub-10 nm spatial temperature resolution.

  12. METHODS OF EVALUATION AND INDICATORS OF OPTIMAL TEMPERATURE OF INTERNAL COMBUSTION ENGINES AND VEHICLES IN OPERATION

    Directory of Open Access Journals (Sweden)

    V. Volkov

    2015-12-01

    Full Text Available The results of forming methods of determination and system, as a part of the computer-integrated technology of transport operation, estimation of indecies of the optimal temperature state of the ICE and the vehicle under operation conditions, which is provided with the help of analysis of possible schemes and processes of the complex system of combined heating, using the technology of heat accumulation are described.

  13. Cell separator operation within temperature ranges to minimize effects on Chinese hamster ovary cell perfusion culture.

    Science.gov (United States)

    Drouin, Hans; Ritter, Joachim B; Gorenflo, Volker M; Bowen, Bruce D; Piret, James M

    2007-01-01

    A cell retention device that provides reliable high-separation efficiency with minimal negative effects on the cell culture is essential for robust perfusion culture processes. External separation devices generally expose cells to periodic variations in temperature, most commonly temperatures below 37 degrees C, while the cells are outside the bioreactor. To examine this phenomenon, aliquots of approximately 5% of a CHO cell culture were exposed to 60 s cyclic variations of temperature simulating an acoustic separator environment. It was found that, for average exposure temperatures between 31.5 and 38.5 degrees C, there were no significant impacts on the rates of growth, glucose consumption, or t-PA production, defining an acceptable range of operating temperatures. These results were subsequently confirmed in perfusion culture experiments for average exposure temperatures between 31.6 and 38.1 degrees C. A 2(5-1) central composite factorial design experiment was then performed to systematically evaluate the effects of different operating variables on the inlet and outlet temperatures of a 10L acoustic separator. The power input, ambient temperature, as well as the perfusion and recycle flow rates significantly influenced the temperature, while the cell concentration did not. An empirical model was developed that predicted the temperature changes between the inlet and the outlet of the acoustic separator within +/-0.5 degrees C. A series of perfusion experiments determined the ranges of the significant operational settings that maintained the acoustic separator inlet and outlet temperatures within the acceptable range. For example, these objectives were always met by using the manufacturer-recommended operational settings as long as the recirculation flow rate was maintained above 15 L day(-1) and the ambient temperature was near 22 degrees C.

  14. RESIDUAL OPERATIONAL RESOURCE ASSESSMENT OF HIGH TEMPERATURE ELEMENTS OF POWER ENGINEERING EQUIPMENT

    Directory of Open Access Journals (Sweden)

    S. E. Khoroshilov

    2014-01-01

    Full Text Available The paper proposes a specific assessment of heat resistant steel residual resource which  is  based  on  time determination of pore output on grain boundary with due account of an operational temperature, chemical composition and structure of the investigated steel.

  15. Determining collective barrier operation skew in a parallel computer

    Energy Technology Data Exchange (ETDEWEB)

    Faraj, Daniel A.

    2015-11-24

    Determining collective barrier operation skew in a parallel computer that includes a number of compute nodes organized into an operational group includes: for each of the nodes until each node has been selected as a delayed node: selecting one of the nodes as a delayed node; entering, by each node other than the delayed node, a collective barrier operation; entering, after a delay by the delayed node, the collective barrier operation; receiving an exit signal from a root of the collective barrier operation; and measuring, for the delayed node, a barrier completion time. The barrier operation skew is calculated by: identifying, from the compute nodes' barrier completion times, a maximum barrier completion time and a minimum barrier completion time and calculating the barrier operation skew as the difference of the maximum and the minimum barrier completion time.

  16. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Ambient air temperature and operating... Information Operating Limitations § 25.1527 Ambient air temperature and operating altitude. The extremes of the ambient air temperature and operating altitude for which operation is allowed, as limited...

  17. Li/CFx Cells Optimized for Low-Temperature Operation

    Science.gov (United States)

    Smart, Marshall C.; Whitacre, Jay F.; Bugga, Ratnakumar V.; Prakash, G. K. Surya; Bhalla, Pooja; Smith, Kiah

    2009-01-01

    Some developments reported in prior NASA Tech Briefs articles on primary electrochemical power cells containing lithium anodes and fluorinated carbonaceous (CFx) cathodes have been combined to yield a product line of cells optimized for relatively-high-current operation at low temperatures at which commercial lithium-based cells become useless. These developments have involved modifications of the chemistry of commercial Li/CFx cells and batteries, which are not suitable for high-current and low-temperature applications because they are current-limited and their maximum discharge rates decrease with decreasing temperature. One of two developments that constitute the present combination is, itself, a combination of developments: (1) the use of sub-fluorinated carbonaceous (CFx wherein xLiBF4 dissolved at a concentration of 0.5 M in a mixture of four volume parts of 1,2 dimethoxyethane with one volume part of propylene carbonate. The proportion, x, of fluorine in the cathode in such a cell lies between 0.5 and 0.9. The best of such cells fabricated to date have exhibited discharge capacities as large as 0.6 A h per gram at a temperature of 50 C when discharged at a rate of C/5 (where C is the magnitude of the current, integrated for one hour, that would amount to the nominal charge capacity of a cell).

  18. Performance of Wide Operating Temperature Range Electrolytes in Quallion Prototype Li-Ion Cells

    Science.gov (United States)

    Smart, M. C.; Ratnakumar, B. V.; Tomcsi, M. R.; Nagata, M.; Visco, V.; Tsukamoto, H.

    2010-01-01

    For a number of applications, there is a continued interest in the development of rechargeable lithium-based batteries that can effectively operate over a wide temperature range (i.e., -40 to +70 deg C). These applications include powering future planetary rovers for NASA, enabling the next generation of automotive batteries for DOE, and supporting many DOD applications. Li-ion technology has been demonstrated to have good performance over a reasonably wide temperature range with many systems; however, there is still a desire to improve the low temperature rate capacity as well as the high temperature resilience. In the current study, we would like to present recent results obtained with prototype Li-Ion cells (manufactured by Quallion, LLC) which include various wide operating temperature range electrolytes developed by both JPL and Quallion. To demonstrate the viability of the technology, a number of performance tests were carried out, including: (a) discharge rate characterization over a wide temperature range (down to -60 deg C) using various rates (up to 20C rates), (b) discharge rate characterization at low temperatures with low temperature charging, (c) variable temperature cycling over a wide temperature range (-40 to +70 deg C), and (d) cycling at high temperature (50 deg C). As will be discussed, impressive rate capability was observed at low temperatures with many systems, as well as good resilience to high temperature cycling. To augment the performance testing on the prototype cells, a number of experimental three electrodes cells were fabricated (including Li reference electrodes) to allow the determination of the lithium kinetics of the respective electrodes and interfacial properties as a function of temperatures.

  19. Geostationary Operational Environmental Satellite (GOES) Gyro Temperature Model

    Science.gov (United States)

    Rowe, J. N.; Noonan, C. H.; Garrick, J.

    1996-01-01

    The geostationary Operational Environmental Satellite (GOES) 1/M series of spacecraft are geostationary weather satellites that use the latest in weather imaging technology. The inertial reference unit package onboard consists of three gyroscopes measuring angular velocity along each of the spacecraft's body axes. This digital integrating rate assembly (DIRA) is calibrated and used to maintain spacecraft attitude during orbital delta-V maneuvers. During the early orbit support of GOES-8 (April 1994), the gyro drift rate biases exhibited a large dependency on gyro temperature. This complicated the calibration and introduced errors into the attitude during delta-V maneuvers. Following GOES-8, a model of the DIRA temperature and drift rate bias variation was developed for GOES-9 (May 1995). This model was used to project a value of the DIRA bias to use during the orbital delta-V maneuvers based on the bias change observed as the DIRA warmed up during the calibration. The model also optimizes the yaw reorientation necessary to achieve the correct delta-V pointing attitude. As a result, a higher accuracy was achieved on GOES-9 leading to more efficient delta-V maneuvers and a propellant savings. This paper summarizes the: Data observed on GOES-8 and the complications it caused in calibration; DIRA temperature/drift rate model; Application and results of the model on GOES-9 support.

  20. Ultra high temperature diffusion apparatus and operating procedures

    Energy Technology Data Exchange (ETDEWEB)

    Wyrick, S.B.

    1985-11-15

    It is the purpose of this paper to present an experimental apparatus which is capable of measuring diffusion coefficients of interdiffusing gases in the temperature range 300K to 2500K. Because of the high temperatures which will be encountered, a special alloy of tantalum (T-111) is used to house the diffusion process. This T-111 diffusion cell is heated via radiation heat from a tungsten heating element powered by a Saban saturable reactor power supply. The diffusion cell heating element are encased in a nickel-plated copper cooling can. This entire assembly is enclosed in an Ultek vacuum chamber to prevent oxidation of the diffusion cell. This report covers the construction and calibration of the diffusion cell, details of the gas loading and sampling system, and complete information on the components required to operate the vacuum furnace. Thus far, several experiments have been run in the temperature range 600K to 800K and the resulting diffusion coefficients agree fairly well with previously published values. 21 refs., 9 figs., 4 tabs.

  1. Development of high-temperature superconducting filters operating at temperatures above 90 K

    Institute of Scientific and Technical Information of China (English)

    XIA HouHai; ZHOU ChunXia; ZUO Tao; HE Ming; JI Lu; ZHOU TieGe; ZHAO XinJie; FANG Lan; YAN ShaoLin

    2009-01-01

    This paper represents the development of a high temperature superconducting (HTS) filter, the highest operating temperature of which is up to 93 K. The filter is designed for S band with 4% fractional bandwidth and fabricated using thallium-barium-calcium-copper oxide (Tl_2Ba_2CaCu_2O_8) thin films. At 93 K, the measurements of the filter show that the insertion loss in the passband is less than 0.22 dB, the return loss is better than 20 dB, and the out-of-band rejection is more than 80 dB. The analysis on the characteristics of the filter operating at different temperatures shows that the filter can work well at temperatures around 90 K. The temperature of 93 K is the highest among the previous reports for HTS filters. The result reported in this paper is significant for HTS filters to be used in the field of microwave communication requiring high sensitivity.

  2. Determination of coronal temperatures from electron density profiles

    CERN Document Server

    Lemaire, J F

    2011-01-01

    The most popular method for determining coronal temperatures is the scale-height-method (shm). It is based on electron density profiles inferred from White Light (WL) brightness measurements of the corona during solar eclipses. This method has been applied to several published coronal electron density models. The calculated temperature distributions reach a maximum at r > 1.3 RS, and therefore do not satisfy one of the conditions for applying the shm method. Another method is the hydrostatic equilibrium method (hst), which enables coronal temperature distributions to be determined, providing solutions to the hydrostatic equilibrium equation. The temperature maximas using the hst method are almost equal to those obtained using the shm method, but the temperature peak is always at significantly lower altitude when the hst-method is used than when the shm-method is used. A third and more recently developed method, dyn, can be used for the same published electron density profiles. The temperature distributions ob...

  3. Determination of Rheological Parameters of Polyvinylchloride at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Chepurnenko A.S.

    2016-01-01

    Full Text Available The paper proposes the method of determining the relaxation constants of the material included in the nonlinear equation of Maxwell-Gurevich. We performed the processing of relaxation curves of recycled polyvinylchloride (PVC at different temperatures and investigated the effect of temperature on the value of the relaxation parameters. For each parameter, we have chosen empirical formula describing its dependence on temperature.

  4. Progress report on the design of a varying temperature irradiation experiment for operation in HFIR

    Energy Technology Data Exchange (ETDEWEB)

    Qualls, A.L. [Oak Ridge National Lab., TN (United States); Muroga, T.

    1997-04-01

    The purpose of this experiment is to determine effects of temperature variation during irradiation on microstructure and mechanical properties of potential fusion reactor structural materials. A varying temperature irradiation experiment is being performed under the framework of the Japan-USA Program of Irradiation Tests for fusion Research (JUPITER) to study the effects of temperature variation on the microstructure and mechanical properties of candidate fusion reactor structural materials. An irradiation capsule has been designed for operation in the High Flux Isotope Reactor at Oak Ridge National Laboratory that will allow four sets of metallurgical test specimens to be irradiated to exposure levels ranging from 5 to 10 dpa. Two sets of specimens will be irradiated at constant temperature of 500{degrees}C and 350{degrees}C. Matching specimen sets will be irradiated to similar exposure levels, with 10% of the exposure to occur at reduced temperatures of 300{degrees}C and 200{degrees}C.

  5. Determination of sea surface temperatures from microwave and IR data

    Science.gov (United States)

    Rangaswamy, S.; Grover, J.

    1982-01-01

    Microwave measurements from the Nimbus 7 SMMR were used to derive the atmospheric precipitable water, which was then used to obtain the atmospheric correction for use with AVHRR thermal IR measurements to obtain sea surface temperature (SST). The resulting SST's were compared with the NOAA operational sea surface temperature measurements, and the two sets of measurements were found to be in reasonable agreement. The average residuals between the two sets of measurements was 0.15 K with the NOAA operational SST's being slightly greater.

  6. Determination of temperature of moving surface by sensitivity analysis

    CERN Document Server

    Farhanieh, B

    2002-01-01

    In this paper sensitivity analysis in inverse problem solutions is employed to estimate the temperature of a moving surface. Moving finite element method is used for spatial discretization. Time derivatives are approximated using Crank-Nicklson method. The accuracy of the solution is assessed by simulation method. The convergence domain is investigated for the determination of the temperature of a solid fuel.

  7. Refractive Secondary Solar Concentrator Demonstrated High-Temperature Operation

    Science.gov (United States)

    Wong, Wayne A.

    2002-01-01

    Space applications that utilize solar thermal energy--such as electric power conversion systems, thermal propulsion systems, and furnaces--require highly efficient solar concentration systems. The NASA Glenn Research Center is developing the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced lightweight primary concentrators, such as inflatable thin films, the refractive secondary concentrator enables very high system concentration ratios and very high temperatures. Last year, Glenn successfully demonstrated a secondary concentrator throughput efficiency of 87 percent, with a projected efficiency of 93 percent using an antireflective coating. Building on this achievement, Glenn recently successfully demonstrated high-temperature operation of the secondary concentrator when it was used to heat a rhenium receiver to 2330 F. The high-temperature demonstration of the concentrator was conducted in Glenn's 68-ft long Tank 6 thermal vacuum facility equipped with a solar simulator. The facility has a rigid panel primary concentrator that was used to concentrate the light from the solar simulator onto the refractive secondary concentrator. NASA Marshall Space Flight Center provided a rhenium cavity, part of a solar thermal propulsion engine, to serve as the high-temperature receiver. The prototype refractive secondary concentrator, measuring 3.5 in. in diameter and 11.2 in. long, is made of single-crystal sapphire. A water-cooled splash shield absorbs spillage light outside of the 3.5-in. concentrator aperture. Multilayer foil insulation composed of tungsten, molybdenum, and niobium is used to minimize heat loss from the hightemperature receiver. A liquid-cooled canister calorimeter is used to measure the heat loss through the multilayer foil insulation.

  8. KINETIC MODELLING OF CONTINUOUS-MIX ANAEROBIC REACTORS OPERATING UNDER DIURNALLY CYCLIC TEMPERATURE ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    E. A. Echiegu

    2014-01-01

    Full Text Available A two-culture dynamic model which incorporated the effects of diurnally cyclic temperature was developed and used to predict the dynamic response of anaerobic reactors operated on dairy manure under two diurnally cyclic temperature ranges of 20-40°C and 15-25°C which represent the summer and winter in Nigeria. The digesters were operated at various hydraulic retention times and solid concentrations and some useful kinetic parameters were determined. The model predicted biogas production, volatile solid reduction, methane yield and treatment efficiency with reasonable accuracy (R2 = 0.70 to 0.90. The model, however, under-predicted the cell mass concentration in the reactor probably because the Volatile Suspended Solid (VSS, which was used as the estimator of the actual cell mass concentration in the reactor, was not a good indicator of the active cell mass concentration in anaerobic reactors operating on dairy manure.

  9. Determination of the yield locus by means of temperature measurement

    NARCIS (Netherlands)

    Banabic, D.; Huetink, J.

    2006-01-01

    The paper presents a theoretical background of the thermo-graphical method of determining the yield locus. The analytical expression of the temperature variation of the specimen deformed in the elastic state is determined starting from the first law of thermodynamics. The experimental method for det

  10. Paleomagnetically Determined Emplacement temperatures of the Explosive cycles of Santorini

    Science.gov (United States)

    Mac Niocaill, C.; Dodd, S. C.; McClelland, E.; Muxworthy, A. R.; Paterson, G. A.

    2013-12-01

    Santorini volcano preserves two major eruptive cycles in the past 300ka. These span 12 pyroclastic eruptions, which are visible as layers in the caldera walls, with the first cycle spanning from 300-180ka and the second spanning from 180-3.6ka. These cycles begin with mafic to intermediate magmas but the terminating pair of eruptions of each cycle involve silicic magmas and major caldera forming events. We present new palaeomagnetic determinations of emplacement temperatures for the Minoan, Upper Scoria, Lower Pumice and Cape Therma deposits, which, in conjunction with published work, means that we now have constraints on the emplacement temperatures of all major pyroclastic deposits within the two grand cycles. Our work establishes that the final two eruptions of each cycle show predominantly lower temperatures than those of intermediate eruptions although there is no 'perfect' cyclic temperature variation seen which would clearly define the cycles. The lower temperatures seen within the intermediate eruptions suggest that composition, and slight differences in the initial magmatic temperature, play very little role in controlling the emplacement temperature. The dominant control on the pyroclastic emplacement temperatures of Santorini appears to be the degree of water interaction into the vent and the percentage of lithics, both of which, when increasing, lower the unit temperature. It may be that the more viscous form of silicic magmas, which causes them to be inherently more explosive, results in the increased likelihood of these eruptions causing higher degrees of water interaction and caldera collapse, and therefore lowering emplacement temperatures.

  11. Determination of cloud-point temperatures for different copolymers

    Directory of Open Access Journals (Sweden)

    G.M. Campese

    2003-09-01

    Full Text Available This paper describes a novel system which has a great potential for use for extractions in biotechnological processes as it uses only polymers and can be operated at moderate temperatures and salt concentrations. The polymers used in this work are ethylene oxide-propylene oxide 10:90 (w/w (EO10PO90 and ethylene oxide-propylene oxide 20:80 (w/w (EO20PO80. The temperature required for thermoseparation decreases with increasing PO content of the copolymer and increasing buffer concentration.

  12. Fiber optic distributed temperature sensing for the determination of air temperature

    NARCIS (Netherlands)

    De Jong, S.A.P.; Slingerland, J.D.; Van de Giesen, N.C.

    2015-01-01

    This paper describes a method to correct for the effect of solar radiation in atmospheric distributed temperature sensing (DTS) applications. By using two cables with different diameters, one can determine what temperature a zero diameter cable would have. Such a virtual cable would not be affected

  13. Quality control methods for KOOS operational sea surface temperature products

    Institute of Scientific and Technical Information of China (English)

    YANG Chansu; KIM Sunhwa

    2016-01-01

    Sea surface temperature SST obtained from the initial version of the Korea Operational Oceanographic System (KOOS) SST satellite have low accuracy during summer and daytime. This is attributed to the diurnal warming effect. Error estimation of SST data must be carried out to use the real-time forecasting numerical model of the KOOS. This study suggests two quality control methods for the KOOS SST system. To minimize the diurnal warming effect, SSTs of areas where wind speed is higher than 5 m/s were used. Depending on the wind threshold value, KOOS SST data for August 2014 were reduced by 0.15°C. Errors in SST data are considered to be a combination of random, sampling, and bias errors. To estimate bias error, the standard deviation of bias between KOOS SSTs and climatology SSTs were used. KOOS SST data yielded an analysis error standard deviation value similar to OSTIA and NOAA NCDC (OISST) data. The KOOS SST shows lower random and sampling errors with increasing number of observations using six satellite datasets. In further studies, the proposed quality control methods for the KOOS SST system will be applied through more long-term case studies and comparisons with other SST systems.

  14. Determination of transient fluid temperature using the inverse method

    Directory of Open Access Journals (Sweden)

    Jaremkiewicz Magdalena

    2014-03-01

    Full Text Available This paper proposes an inverse method to obtain accurate measurements of the transient temperature of fluid. A method for unit step and linear rise of temperature is presented. For this purpose, the thermometer housing is modelled as a full cylindrical element (with no inner hole, divided into four control volumes. Using the control volume method, the heat balance equations can be written for each of the nodes for each of the control volumes. Thus, for a known temperature in the middle of the cylindrical element, the distribution of temperature in three nodes and heat flux at the outer surface were obtained. For a known value of the heat transfer coefficient the temperature of the fluid can be calculated using the boundary condition. Additionally, results of experimental research are presented. The research was carried out during the start-up of an experimental installation, which comprises: a steam generator unit, an installation for boiler feed water treatment, a tray-type deaerator, a blow down flashvessel for heat recovery, a steam pressure reduction station, a boiler control system and a steam header made of martensitic high alloy P91 steel. Based on temperature measurements made in the steam header using the inverse method, accurate measurements of the transient temperature of the steam were obtained. The results of the calculations are compared with the real temperature of the steam, which can be determined for a known pressure and enthalpy.

  15. Assessment of SOI AND Gate, Type CHT-7408, for Operation in Extreme Temperature Environments

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Dones, Keishla Rivera

    2009-01-01

    Electronic parts based on silicon-on-insulator (SOI) technology are finding widespread applications due to their ability to operate in harsh environments and the benefits they offer as compared to their silicon counterparts. Due to their construction, they are tailored for high temperature operation and show good tolerance to radiation events. In addition, their inherent design lessens the formation of parasitic junctions, thereby reducing leakage currents, decreasing power consumption, and enhancing speed. These devices are typically rated in temperature capability from -55 C to about +225 C, and their characteristics over this temperature range are documented in data sheets. Since electronics in some of NASA space exploration missions are required to operate under extreme temperature conditions, both cold and hot, their characteristic behavior within the full temperature spectrum must be determined to establish suitability for use in space applications. The effects of extreme temperature exposure on the performance of a new commercial-off-the-shelf (COTS) SOI AND gate device were evaluated in this work. The high temperature, quad 2-inputs AND gate device, which was recently introduced by CISSOID, is fabricated using a CMOS SOI process. Some of the specifications of the CHT-7408 chip are listed in a table. By supplying a constant DC voltage to one gate input and a 10 kHz square wave into the other associated gate input, the chip was evaluated in terms of output response, output rise (t(sub r)) and fall times (tf), and propagation delays (using a 50% level between input and output during low to high (tPLH) and high to low (tPHL) transitions). The supply current of the gate circuit was also obtained. These parameters were recorded at various test temperatures between -195 C and +250 C using a Sun Systems environmental chamber programmed at a temperature rate of change of 10 C/min. In addition, the effects of thermal cycling on this chip were determined by exposing

  16. Method and Apparatus for Determining Operational Parameters of Thermoelectric Modules

    Science.gov (United States)

    Zybała, Rafał; Schmidt, Maksymilian; Kaszyca, Kamil; Ciupiński, Łukasz; Kruszewski, Mirosław J.; Pietrzak, Katarzyna

    2016-10-01

    The main aim of this work was to construct and test an apparatus for characterization of high temperature thermoelectric modules to be used in thermoelectric generator (TEGs) applications. The idea of this apparatus is based on very precise measurements of heat fluxes passing through the thermoelectric (TE) module, at both its hot and cold sides. The electrical properties of the module, under different temperature and load conditions, were used to estimate efficiency of energy conversion based on electrical and thermal energy conservation analysis. The temperature of the cold side, T c, was stabilized by a precise circulating thermostat (≤0.1°C) in a temperature range from 5°C to 90°C. The amount of heat absorbed by a coolant flowing through the heat sink was measured by the calibrated and certified heat flow meter with an accuracy better than 1%. The temperature of the hot side, T h, was forced to assumed temperature ( T max = 450°C) by an electric heater with known power ( P h = 0-600 W) with ample thermal insulation. The electrical power was used in calculations. The TE module, heaters and cooling plate were placed in an adiabatic vacuum chamber. The load characteristics of the module were evaluated using an electronically controlled current source as a load. The apparatus may be used to determine the essential parameters of TE modules (open circuit voltage, U oc, short circuit current, I sc, internal electrical resistance, R int, thermal resistance, R th, power density, and efficiency, η, as a function of T c and T h ). Several commercially available TE modules based on Bi2Te3 and Sb2Te3 alloys were tested. The measurements confirmed that the constructed apparatus was highly accurate, stable and yielded reproducible results; therefore, it is a reliable tool for the development of thermoelectric generators.

  17. Assessment of the Operating Temperature of Crystalline PV Modules Based on Real Use Conditions

    Directory of Open Access Journals (Sweden)

    Giuseppina Ciulla

    2014-01-01

    Full Text Available Determining the operating temperature Tc of photovoltaic panels PV is important in evaluating the actual performance of these systems. In the literature, different correlations exist, in either explicit or implicit forms, which often do not account for the electrical behaviour of panels; in this way, estimating Tc is based only on the passive behaviour of the PV. In this paper, the authors propose a new implicit correlation that takes into account the standard weather variables and the electricity production regimes of a PV panel in terms of the proximity to the maximum power points. To validate its reliability, the new correlation was tested on two different PV panels (Sanyo and Kyocera panels and the results were compared with values obtained from other common correlations already available in the literature. The data show that the quality of the new correlation drastically improves the estimation of the photovoltaic operating temperature.

  18. DETERMINATION OF TEMPERATURE DISTRIBUTION FOR ANNULAR FINS WITH TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY BY HPM

    Directory of Open Access Journals (Sweden)

    Davood Domairry Ganji

    2011-01-01

    Full Text Available In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity.

  19. Novel test structures for dedicated temperature budget determination

    NARCIS (Netherlands)

    Faber, Erik J.; Wolters, Rob A.M.; Schmitz, Jurriaan

    2012-01-01

    We present a novel method for determining the temperature budget of the process side of silicon substrates and chips, based on well-known silicide formation reactions of metal–Si systems and (four-point probe) resistance measurements. In this paper, we focus on the Pd–Si system that is most temperat

  20. Operation of a Giant Magnetoresistive (GMR) Digital Isolator, Type IL510, Under Extreme Temperatures

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Panko, Scott

    2010-01-01

    A relatively new type of signal isolation based on Giant Magnetoresistive (GMR) technology was investigated for potential use in harsh temperature environments. Operational characteristics of the 2Mbps single channel, IL510-Series commercial-off-the-shelf (COTS) digital isolator chip was obtained under extreme temperature exposure and thermal cycling in the range of -190 C to +120 C. The isolator was evaluated in terms of its output signal delivery and stability, output rise (t(sub r)) and fall times (t(sub f)), and propagation delays at 50% level between input and output during low to high (t(sub PLH)) and high to low (t(sub PHL)) transitions. The device performed very well throughout the entire test temperature range as no significant changes occurred either in its function or in its output signal timing characteristics. The limited thermal cycling, which comprised of 12 cycles between -190 C and +120 C, also had no influence on its performance. In addition, the device packaging underwent no structural damage due to the extreme temperature exposure. These preliminary results indicate that this semiconductor chip has the potential for use in a temperature range that extends beyond its specified regime. Additional and more comprehensive testing, however, is required to establish its operation and reliability and to determine its suitability for long-term use in space exploration missions.

  1. Operating temperatures of open-rack installed photovoltaic inverters

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Wang, L.; Kurtz, S.; Wu, J.; Quan, P.; Sorensen, R.; Liu, S.; Bai, J. B.; Zhu, Z. W.

    2016-11-01

    This paper presents a model for evaluating the heat-sink and component temperatures of open-rack installed photovoltaic inverters. These temperatures can be used for predicting inverter reliability. Inverter heat-sink temperatures were measured for inverters connected to three grid-connected PV (photovoltaic) test systems in Golden, Colorado, US. A model is proposed for calculating the inverter heat-sink temperature based on the ambient temperature, the ratio of the consumed power to the rated power of the inverter, and the measured wind speed. To verify and study this model, more than one year of inverter DC/AC power, irradiance, wind speed, and heat sink temperature rise data were collected and analyzed. The model is shown to be accurate in predicting average inverter temperatures, but will require further refinement for prediction of transient temperatures.

  2. Optimal temperature range for determining magnetocaloric magnitudes from heat capacity

    Science.gov (United States)

    Moreno-Ramírez, L. M.; Blázquez, J. S.; Law, J. Y.; Franco, V.; Conde, A.

    2016-12-01

    The determination of the magnetocaloric magnitudes (specific magnetic entropy change, Δs M, and adiabatic temperature change, ΔT ad) from heat capacity (c H) measurements requires measurements performed at very low temperatures (~0 K) or data extrapolation when the low temperature range is unavailable. In this work we analyze the influence on the calculated Δs M and ΔT ad of the usually employed linear extrapolation of c H from the initial measured temperature down to 0 K. Numerical simulations have been performed using the Brillouin equation of state, the Debye model and the Fermi electron statistics to reproduce the magnetic, lattice and electronic subsystems, respectively. It is demonstrated that it is not necessary to reach experimentally temperatures very close to 0 K due to the existence of certain starting temperatures of the experiments, the same for Δs M and ΔT ad, that minimize the error of the results. A procedure is proposed to obtain the experimental magnitudes of Δs M and ΔT ad with a minimum error from c H data limited in temperature. It has been successfully applied to a GdZn alloy and results are compared to those derived from magnetization measurements.

  3. Investigating the temperature dependence of photomultiplier quantum efficiency when operating in the visible spectrum

    CERN Document Server

    Clawson, Savannah Ellen

    2017-01-01

    The quantum efficiency of a Burle 8850 photomultiplier tube with a potassium-caesium-antimony (bialkali) photocathode was determined by attenuating a 1 mW HeNe laser emitting at 633 nm and measuring the signal frequency when the laser was incident on the photomultiplier. A temperature range of 5 $^{\\circ}$C $-$ 20 $^{\\circ}$C was investigated and it was found that the quantum efficiency decreases with temperature, with the signal frequency decreasing at a faster rate than the dark current frequency. Therefore, it was concluded that it would not be beneficial to cool photomultiplier tubes operating in the visible spectrum for use in collinear laser spectroscopy due to a decreasing signal-to-noise ratio. The signal pulse height distribution was also analysed and found to be independent of temperature within the range investigated.

  4. Determination of cardinal temperatures for sugar apple ( Annona squamosa L.

    Directory of Open Access Journals (Sweden)

    Bruno Rafael Alves Rodrigues

    2016-04-01

    Full Text Available ABSTRACT The sugar apple is highly dependent on the pollination and fruit tree pollen performance is crucial for successful fertilization and fruit set. The objective of this study was to determine the cardinal temperatures for in vitro pollen grains germination and evaluate the effect of temperature on pollen tube growth of sugar apple. The experimental design was in a completely randomized with eight treatments (10, 15, 20, 25, 30, 35, 40 and 45 ºC, four replicates and each plot was constituted by two slides per parcel. The cardinal temperatures were determined by evaluating in vitro germination of pollen grains and pollen tube growth in standard culture medium. It also assessed the pollen tube growth and the percentage of germination in vitro depending on the type of pollen grain arrangement (monad, dyad, triad and tetrad. In vitro germination of pollen grains and pollen tube growth varied significantly with temperature. The maximum germination recorded (48.13% and the maximum lengths of pollen tubes (536.45 μm were obtained when pollen grains were cultivated at 25 ºC. The estimated cardinal temperatures were 9.7, 26.9 and 44.2 ºC. Among the pollen grain arrangements, tetrads pollen grains were observed in higher proportions, however, monads pollen grains presented higher germination percentage.

  5. Determination of the effectiveness of concentrating mine-tunneling operations

    Energy Technology Data Exchange (ETDEWEB)

    Domanov, P.I.

    1979-02-01

    Experimental operations were conducted in 163 tunneling faces equipped with loading machines and mounted drilling machines and in 110 faces equipped with the pneumatic drilling machines 1PNB-2E in order to determine the optimal specific population of tunnellers in a working face. Following computerized processing of the obtained data, mathematical formulas were derived to compute the optimal rate of tunneling drifts with respect to productivity. Relationships were given for the productivity of drift miners and the rate of tunneling drifts, and between the complete cost of tunneling a drift and the velocity of tunneling. 3 figures.

  6. Determining operating policies for a water resource system

    Science.gov (United States)

    Dagli, C. H.; Miles, J. F.

    1980-07-01

    The object of the study described in this paper was to find a method of determining operating policies for a set of four dams which are to be constructed on the Firat (Euphrates) River in Turkey. Each of the dams has an associated hydro-electric power plant, and there are requirements to supply water for irrigation, as well as maintaining river flows downstream of the dams into Syria and Iraq. The problem is thus complex and conventional stochastic models would entail an excessive amount of computation. Moreover, the set of feasible operating policies is so large that simulation cannot be considered a viable alternative. The method adopted might be described as adaptive planning (AP). At time l a forecast is made of the inflow values expected during the planning period and using these forecast values a deterministic model of the system is solved to obtain an operating policy for time l + 1. The forecast is updated and the model re-run at each successive time period to yield revised policies based on the latest available data. The solution obtained by this method for a five-year test period, using historical data, was within 0.4% of the optimal solution.

  7. Comparison of methods for physical determination of phase transformations temperatures

    Directory of Open Access Journals (Sweden)

    S. Rusz

    2013-10-01

    Full Text Available Various physical methods for the determination of phase transformation temperatures were compared using C-Mn and C-Mn-V-Nb steels. The measurement using temperature scanner, variously located thermocouples, dilatometer, different thermal analysis (DTA and anisothermal plastometric test were completed. The specimens were heated to 1 323 K and 1 473 K in the case of the C-Mn-V-Nb microalloyed steel. The aim of the different heat treatment were to obtain different levels of precipitates’ dissolution. It was found that the better particles’ distribution and precipitation due to the cooling lead to the enlargement of the two-phase region in the material. The good agreement of result gained by used methods was achieved. We found that all used methods can be used for common steels, but the temperature scanner seems not to be precious enough for microalloyed steels.

  8. Determination of gas temperature in the plasmatron channel according to the known distribution of electronic temperature

    Directory of Open Access Journals (Sweden)

    Gerasimov Alexander V.

    2013-01-01

    Full Text Available An analytical method to calculate the temperature distribution of heavy particles in the channel of the plasma torch on the known distribution of the electronic temperature has been proposed. The results can be useful for a number of model calculations in determining the most effective conditions of gas blowing through the plasma torch with the purpose of heating the heavy component. This approach allows us to understand full details about the heating of cold gas, inpouring the plasma, and to estimate correctly the distribution of the gas temperature inside the channel.

  9. Electrolytes for Low-Temperature Operation of Li-CFx Cells

    Science.gov (United States)

    Smart, Marshall C.; Whitacre, Jay F.; Bugga, Ratnakumar V.; Prakash, G. K. Surya; Bhalla, Pooja; Smith, Kiah

    2009-01-01

    A report describes a study of electrolyte compositions selected as candidates for improving the low-temperature performances of primary electrochemical cells that contain lithium anodes and fluorinated carbonaceous (CFx) cathodes. This study complements the developments reported in Additive for Low-Temperature Operation of Li-(CF)n Cells (NPO- 43579) and Li/CFx Cells Optimized for Low-Temperature Operation (NPO- 43585), which appear elsewhere in this issue of NASA Tech Briefs. Similar to lithium-based electrolytes described in several previous NASA Tech Briefs articles, each of these electrolytes consisted of a lithium salt dissolved in a nonaqueous solvent mixture. Each such mixture consisted of two or more of the following ingredients: propylene carbonate (PC); 1,2-dimethoxyethane (DME); trifluoropropylene carbonate; bis(2,2,2-trifluoroethyl) ether; diethyl carbonate; dimethyl carbonate; and ethyl methyl carbonate. The report describes the physical and chemical principles underlying the selection of the compositions (which were not optimized) and presents results of preliminary tests made to determine effects of the compositions upon the low-temperature capabilities of Li-CFx cells, relative to a baseline composition of LiBF4 at a concentration of 1.0 M in a solvent comprising equal volume parts of PC and DME.

  10. Determination of the temperature artifact during ultrasound hyperthermia.

    Science.gov (United States)

    Waterman, F M

    1990-01-01

    Temperature artifacts produced by very small uncoated thermocouples during ultrasonic heating are evaluated by backward extrapolation of the linear portion of the temperature rise curve or by backward extrapolation of the exponential portion of the temperature decay curve. The accuracy of these techniques for larger clinically used thermocouples is investigated by use of a two-dimensional model of the bioheat equation which simulates the transfer of heat radially from a probe 1 mm in diameter. The accuracy of these techniques is found to depend upon the perfusion rate. In the absence of perfusion, both extrapolation techniques underestimate the artifact by nearly 40%. Extrapolation of the temperature rise curve is very sensitive to the perfusion rate and this technique results in errors exceeding 100% when the perfusion rate is high. Extrapolation of the temperature decay curve produces more consistent results. Over a blood flow range of 0-100 ml/100 g per min, the artifact is underestimated by an amount that varies from approximately 40% to 30% respectively. Thus, the artifact can be determined to within 5% by this technique by increasing the extrapolated value by 35%.

  11. A Method for more specific Simulation of Operative Temperature in Thermal Analysis Programmes

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik

    2008-01-01

    Simulation of energy consumption of buildings on hourly basis is closely connected to the thermal indoor climate. The operative temperature can be used as a simple measure for thermal environment. The operative temperature is a function of the air temperature, the mean radiant temperature and the...... for calculating the angular factor and shows how a matrix solution for the angular factor can easily be implemented in programs for dynamic building thermal analysis.......Simulation of energy consumption of buildings on hourly basis is closely connected to the thermal indoor climate. The operative temperature can be used as a simple measure for thermal environment. The operative temperature is a function of the air temperature, the mean radiant temperature...

  12. Space Electronics Operating at High Temperatures and Radiation Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposal represents a radical revolution in Power Management & Distribution (PMAD) that addresses many of the challenges for NASA missions that will operate...

  13. Impact of Radiation Hardness and Operating Temperatures of Silicon Carbide Electronics on Space Power System Mass

    Science.gov (United States)

    Juhasz, Albert J.; Tew, Roy C.; Schwarze, Gene E.

    1998-01-01

    The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e) , 1 MW(e), and 10 MW(e)) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass.

  14. Performance of a spacecraft DC-DC converter breadboard modified for low temperature operation

    Science.gov (United States)

    Gerber, Scott S.; Stell, Chris; Patterson, Richard; Ray, Biswajit

    1996-01-01

    A 1OW 3OV/5.OV push-pull dc-dc converter breadboard, designed by the Jet Propulsion Laboratory (JPL) with a +50 C to +5 C operating range for the Cassini space probe, was characterized for lower operating temperatures. The breadboard converter which failed to operate for temperatures below -125 C was then modified to operate at temperatures approaching that of liquid nitrogen (LN2). Associated with this low operating temperature range (greater than -196 C) was a variety of performance problems such as significant change in output voltage, converter switching instability, and failure to restart at temperatures below -154 C. An investigation into these problems yielded additional modifications to the converter which improved low temperature performance even further.

  15. Determination of flame temperature using laser induced fluorescence (LIF)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Lina Augusta Martins Ramos da [Instituto Tecnologico de Aeronautica (ITA/DCTA), Sao Jose dos Campos, SP (Brazil); Barreta, Gilberto; Carinhana Junior, Dermeval; Toledo, Antonio Osny de [Instituto de Estudos Avancados (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil)

    2011-07-01

    Full text: Laser Induced Fluorescence, LIF, is one of the most used techniques in combustion diagnostics. The excitation method is based on the spontaneous spectrum from atoms or molecules that were excited by laser radiation. In general, intermediated combustion species, as OH and CH radicals, are used as temperature probes. Usually, several rotational levels are used by tuning the laser afterwards across the corresponding absorption transitions. The emission spectrum is detected in a convenient spectral range. The accuracy of measurements depends on the laser linewidth, the delay between the laser excitation and spectra detection and, mainly, the spectral interval of laser excitation. In this work, OH LIF spectra from stoichiometric LPG (Liquefied Petroleum Gas) flames were obtained using a tuned laser with a spectral range set from 282 nm up to 283 nm. This corresponds to the rotation levels of the 0-1 vibration band of OH radical. The laser energy was ca. 0.2 mJ. The emission spectrum was collected in the spectral range of the 305-310 nm, which corresponds to the region of the 0-0 band. The temperature was determined by the Boltzmann method. This is based on the measurement of the relative peak intensities of the emission spectrum. A plot of natural logarithm of line intensities versus energy level returns a straight line, whose slope is the inverse of the rotational temperature. The flame temperature was ca. 2300 K. This value is consistent with previous results obtained in our laboratory. (author)

  16. Operational Temperature Effect on Positioning Accuracy of a Single-Axial Moving Carrier

    Directory of Open Access Journals (Sweden)

    Kun-Ying Li

    2017-04-01

    Full Text Available This study investigated the ambient environmental temperature effect on the positioning accuracy of a periodically-moving carrier. The moving carrier was operated in an environmental chamber in which the operational temperature could be controlled by an air conditioning system. Different operational temperature modes, including a stable environment, a rise in temperature, a decline in temperature, summer daytime hours, and winter nighttime hours in terms of seasonal climate change in Taiwan, were generated within the environmental chamber by an air conditioning system to investigate the operational temperature’s effect on positioning accuracy. From the experimental measurements of a periodically-moving carrier, it is found that the operational temperature conditions can significantly affect the positioning accuracy of the moving carrier, especially in the case of an operational temperature decline. Under stable operational conditions, the positioning accuracy of the moving carrier can be considerably improved. In comparison to the case of an operational temperature decline, the positioning accuracy improvement can reach 29.6%. Moreover, the effect of the temperature distributions within the chamber on the positioning accuracy was further investigated. It was found that, with a parallel flow pattern in the chamber, the positioning accuracy can be further enhanced.

  17. Low-temperature operation of a Buck DC/DC converter

    Science.gov (United States)

    Ray, Biswajit; Gerber, Scott S.; Patterson, Richard L.; Myers, Ira T.

    1995-01-01

    Low-temperature (77 K) operation of a 42/28 V, 175 W, 50 kHz PWM Buck DC/DC converter designed with commercially available components is reported. Overall, the converter losses decreased at 77 K compared to room temperature operation. A full-load efficiency of 97 percent was recorded at liquid-nitrogen temperature, compared to 95.8 percent at room temperature. Power MOSFET operation improved significantly where as the output rectifier operation deteriorated at low-temperature. The performance of the output filter inductor and capacitor did not change significantly at 77 K compared to room temperature performance. It is possible to achieve high-density and high efficiency power conversion at low-temperatures due to improved electronic, electrical and thermal properties of materials.

  18. Lithium Batteries and Supercapacitors Capable of Operating at Low Temperatures for Planetary Exploration

    Science.gov (United States)

    Smart, M. C.; Ratnakumar, B. V.; West, W. C.; Brandon, E. J.

    2012-01-01

    Demonstrated improved performance with wide operating temperature electrolytes containing ester co - solvents (i.e., methyl propionate and ethyl butyrate) in a number of prototype cells: center dot Successfully scaled up low temperature technology to 12 Ah size prismatic Li - ion cells (Quallion, LCC), and demonstrated good performance down to - 60 o C. center dot Demonstrated wide operating temperature range performance ( - 60 o to +60 o C) in A123 Systems LiFePO 4 - based lithium - ion cells containing methyl butyrate - based low temperature electrolytes. These systems were also demonstrated to have excellent cycle life performance at ambient temperatures, as well as the ability to be cycled up to high temperatures.

  19. Thermal measurement. Nanoscale temperature mapping in operating microelectronic devices.

    Science.gov (United States)

    Mecklenburg, Matthew; Hubbard, William A; White, E R; Dhall, Rohan; Cronin, Stephen B; Aloni, Shaul; Regan, B C

    2015-02-06

    Modern microelectronic devices have nanoscale features that dissipate power nonuniformly, but fundamental physical limits frustrate efforts to detect the resulting temperature gradients. Contact thermometers disturb the temperature of a small system, while radiation thermometers struggle to beat the diffraction limit. Exploiting the same physics as Fahrenheit's glass-bulb thermometer, we mapped the thermal expansion of Joule-heated, 80-nanometer-thick aluminum wires by precisely measuring changes in density. With a scanning transmission electron microscope and electron energy loss spectroscopy, we quantified the local density via the energy of aluminum's bulk plasmon. Rescaling density to temperature yields maps with a statistical precision of 3 kelvin/hertz(-1/2), an accuracy of 10%, and nanometer-scale resolution. Many common metals and semiconductors have sufficiently sharp plasmon resonances to serve as their own thermometers. Copyright © 2015, American Association for the Advancement of Science.

  20. High accuracy magnetic field sensors with wide operation temperature range

    Science.gov (United States)

    Vasil'evskii, I. S.; Vinichenko, A. N.; Rubakin, D. I.; Bolshakova, I. A.; Kargin, N. I.

    2016-10-01

    n+InAs(Si) epitaxial thin films heavily doped by silicon and Hall effect magnetic field sensors based on this structures have been fabricated and studied. We have demonstrated the successful formation of highly doped InAs thin films (∼100 nm) with the different intermediate layer arrangement and appropriate electron mobility values. Hall sensors performance parameters have been measured in wide temperature range. Obtained sensitivity varied from 1 to 40 Ω/T, while the best linearity and lower temperature coefficient have been found in the higher doped samples with lower electron mobility. We attribute this to the electron system degeneracy and decreased phonon contribution to electron mobility and resistance.

  1. Neighborhood properties are important determinants of temperature sensitive mutations.

    Directory of Open Access Journals (Sweden)

    Svetlana Lockwood

    Full Text Available Temperature-sensitive (TS mutants are powerful tools to study gene function in vivo. These mutants exhibit wild-type activity at permissive temperatures and reduced activity at restrictive temperatures. Although random mutagenesis can be used to generate TS mutants, the procedure is laborious and unfeasible in multicellular organisms. Further, the underlying molecular mechanisms of the TS phenotype are poorly understood. To elucidate TS mechanisms, we used a machine learning method-logistic regression-to investigate a large number of sequence and structure features. We developed and tested 133 features, describing properties of either the mutation site or the mutation site neighborhood. We defined three types of neighborhood using sequence distance, Euclidean distance, and topological distance. We discovered that neighborhood features outperformed mutation site features in predicting TS mutations. The most predictive features suggest that TS mutations tend to occur at buried and rigid residues, and are located at conserved protein domains. The environment of a buried residue often determines the overall structural stability of a protein, thus may lead to reversible activity change upon temperature switch. We developed TS prediction models based on logistic regression and the Lasso regularized procedure. Through a ten-fold cross-validation, we obtained the area under the curve of 0.91 for the model using both sequence and structure features. Testing on independent datasets suggested that the model predicted TS mutations with a 50% precision. In summary, our study elucidated the molecular basis of TS mutants and suggested the importance of neighborhood properties in determining TS mutations. We further developed models to predict TS mutations derived from single amino acid substitutions. In this way, TS mutants can be efficiently obtained through experimentally introducing the predicted mutations.

  2. Silicon solar cell monitors high temperature furnace operation

    Science.gov (United States)

    Zellner, G. J.

    1968-01-01

    Silicon solar cell, attached to each viewpoint, monitors that incandescent emission from the hot interior of a furnace without interfering with the test assembly or optical pyrometry during the test. This technique can provide continuous indication of hot spots or provide warning of excessive temperatures in cooler regions.

  3. Operational efficiency of ballast water biocides at low water temperatures

    NARCIS (Netherlands)

    Kaag, N.H.B.M.; Sneekes, A.C.

    2015-01-01

    In the period 2013-2015 the effect of two biocides used for the treatment of ballast water has been evaluated at low ambient temperatures. Peraclean® Ocean and sodium hypochlorite were used as biocides. Most of the tests were conducted during winter and early spring at the laboratories of IMARES in

  4. Electrolytes for Wide Operating Temperature Lithium-Ion Cells

    Science.gov (United States)

    Smart, Marshall C. (Inventor); Bugga, Ratnakumar V. (Inventor)

    2016-01-01

    Provided herein are electrolytes for lithium-ion electrochemical cells, electrochemical cells employing the electrolytes, methods of making the electrochemical cells and methods of using the electrochemical cells over a wide temperature range. Included are electrolyte compositions comprising a lithium salt, a cyclic carbonate, a non-cyclic carbonate, and a linear ester and optionally comprising one or more additives.

  5. Operational experience with room temperature continuous wave accelerator structures

    Science.gov (United States)

    Alimov, A. S.; Ishkhanov, B. S.; Piskarev, I. M.; Shvedunov, V. I.; Tiunov, A. V.

    1993-05-01

    The paper reports the results of the computer simulation of parameters of the on-axis coupled accelerator structure for the continuous wave racetrack microtron. The operational experience with the accelerating sections on the basis of the on-axis coupled structure is described.

  6. Settlement determination of operating moisture of autoclaved aerated concrete in different climatic zones

    Directory of Open Access Journals (Sweden)

    Pastushkov Pavel Pavlovich

    Full Text Available In the process of operation of buildings the moisture state of enveloping structures materials is changing depending on their construction features, properties of the material, temperature and moisture conditions in the premises, climatic conditions of the construction area. Moisture mode determines the operational properties of the enveloping structures of a building. It directly influences the thermal characteristics of enveloping structure and energy efficiency of the applied materials. The analysis of the methods for calculation of moisture behavior of enclosing structures is carried out. The research relevance of operational moisture of AAC is substantiated. Experimental studies and results of the sorption moisturizing and water vapor permeability of leading marks of aerated concrete are carried out. The authors offer the results of numerical calculations of the moisture behavior of aerated concrete in the walls with mark D400 with facade thermal insulation composite systems - with external plaster layers for different climatic zones of construction.

  7. CdZnTe room-temperature semiconductor operation in liquid scintillator

    CERN Document Server

    Stewart, D Y

    2008-01-01

    We demonstrate the first operation of CdZnTe room-temperature detectors in a liquid scintillator environment. This work follows conceptually the Heusser-type detector method of operating HPGe detectors in liquid nitrogen and liquid argon but instead for a far more practical room-temperature ensemble with the aim of achieving ultra-low background levels for radiation detection.

  8. Ge-on-Si laser operating at room temperature.

    Science.gov (United States)

    Liu, Jifeng; Sun, Xiaochen; Camacho-Aguilera, Rodolfo; Kimerling, Lionel C; Michel, Jurgen

    2010-03-01

    Monolithic lasers on Si are ideal for high-volume and large-scale electronic-photonic integration. Ge is an interesting candidate owing to its pseudodirect gap properties and compatibility with Si complementary metal oxide semiconductor technology. Recently we have demonstrated room-temperature photoluminescence, electroluminescence, and optical gain from the direct gap transition of band-engineered Ge-on-Si using tensile strain and n-type doping. Here we report what we believe to be the first experimental observation of lasing from the direct gap transition of Ge-on-Si at room temperature using an edge-emitting waveguide device. The emission exhibited a gain spectrum of 1590-1610 nm, line narrowing and polarization evolution from a mixed TE/TM to predominantly TE with increasing gain, and a clear threshold behavior.

  9. Electrolytes for Use in High Energy Lithium-Ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2011-01-01

    Objectives of this work are: (1) Develop advanced Li -ion electrolytes that enable cell operation over a wide temperature range (i.e., -30 to +60C). (2) Improve the high temperature stability and lifetime characteristics of wide operating temperature electrolytes. (3) Improve the high voltage stability of these candidate electrolytes systems to enable operation up to 5V with high specific energy cathode materials. (4) Define the performance limitations at low and high temperature extremes, as well as, life limiting processes. (5) Demonstrate the performance of advanced electrolytes in large capacity prototype cells.

  10. Effect of operating temperature on LMFBR core performance

    Energy Technology Data Exchange (ETDEWEB)

    Noyes, R.C.; Bergeron, R.J.; di Lauro, G.F.; Kulwich, M.R.; Stuteville, D.W.

    1977-04-11

    The purpose of the study is to provide an engineering evaluation of high and low temperature LMFBR core designs. The study was conducted by C-E supported by HEDL expertise in the areas of materials behavior, fuel performance and fabrication/fuel cycle cost. The evaluation is based primarily on designs and analyses prepared by AI, GE and WARD during Phase I of the PLBR studies.

  11. Effects of temperature conditions in a gas collector on operation of primary and secondary gas coolers

    Energy Technology Data Exchange (ETDEWEB)

    Chuishchev, V.M.; Selivanova, Z.G.; Vasyuta, V.I.

    1988-04-01

    Discusses composition of coal gas leaving coke ovens and temperature effects on its composition in a gas collector and cooling systems. Effects of coal gas temperature ranging from 78 to 90 C on operation of cooling systems are analyzed: cooling intensity, naphthalene buildup, etc. Analyses show that coal gas temperature fluctuations from 80 to 90 C do not influence gas collector operation, whereas operation of primary gas coolers is influenced by gas collector operation. When coal gas temperature is reduced from 88 to 80 C intensity of coal tar accumulation increases 2 times and that of naphthalene increases 5 to 6 times. Temperature of coal gas leaving the primary coolers ranges from 35 to 40 C. Types of primary coal gas coolers, their operation and performance are comparatively evaluated. Effects of gas cooler design on efficiency of coal tar separation from coal gas are discussed. 5 refs.

  12. High Temperature Electrolysis Pressurized Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; G.K. Housley; K. DeWall; L. Moore-McAteer

    2012-09-01

    A new facility has been developed at the Idaho National Laboratory for pressurized testing of solid oxide electrolysis stacks. Pressurized operation is envisioned for large-scale hydrogen production plants, yielding higher overall efficiencies when the hydrogen product is to be delivered at elevated pressure for tank storage or pipelines. Pressurized operation also supports higher mass flow rates of the process gases with smaller components. The test stand can accommodate planar cells with dimensions up to 8.5 cm x 8.5 cm and stacks of up to 25 cells. It is also suitable for testing other cell and stack geometries including tubular cells. The pressure boundary for these tests is a water-cooled spool-piece pressure vessel designed for operation up to 5 MPa. Pressurized operation of a ten-cell internally manifolded solid oxide electrolysis stack has been successfully demonstrated up 1.5 MPa. The stack is internally manifolded and operates in cross-flow with an inverted-U flow pattern. Feed-throughs for gas inlets/outlets, power, and instrumentation are all located in the bottom flange. The entire spool piece, with the exception of the bottom flange, can be lifted to allow access to the internal furnace and test fixture. Lifting is accomplished with a motorized threaded drive mechanism attached to a rigid structural frame. Stack mechanical compression is accomplished using springs that are located inside of the pressure boundary, but outside of the hot zone. Initial stack heatup and performance characterization occurs at ambient pressure followed by lowering and sealing of the pressure vessel and subsequent pressurization. Pressure equalization between the anode and cathode sides of the cells and the stack surroundings is ensured by combining all of the process gases downstream of the stack. Steady pressure is maintained by means of a backpressure regulator and a digital pressure controller. A full description of the pressurized test apparatus is provided in this

  13. Determination of Soil Evaporation Fluxes Using Distributed Temperature Sensing Methods

    Science.gov (United States)

    Munoz, J.; Serna, J. L.; Suarez, F. I.

    2015-12-01

    Evaporation is the main process for water vapor exchange between the land surface and the atmosphere. Evaporation from shallow groundwater tables is important in arid zones and is influenced by the water table depth and by the soil's hydrodynamic characteristics. Measuring evaporation, however, is still challenging. Thus, it is important to develop new measuring techniques that can better determine evaporation fluxes. The aim of this work is to investigate the feasibility of using distributed-temperature-sensing (DTS) to study the processes that control evaporation from soils with shallow water tables. To achieve this objective, an experimental column was instrumented with traditional temperature probes, time-domain-reflectometry probes, and an armored fiber-optic cable that allowed the application of heat pulses to estimate the soil moisture profile. The experimental setup also allowed to fix the water table at different depths and to measure evaporation rates at the daily scale. Experiments with different groundwater table depths were carried out. For each experiment, the evaporation rates were measured and the moisture profile was determined using heat pulses all through the DTS cable. These pulses allowed estimation of the moisture content with errors smaller than 0.045 m3/m3 and with a spatial resolution of ~6.5 mm. The high spatial resolution of the moisture profile combined with mathematical modeling permitted to investigate the processes that control evaporation from bare soils with shallow groundwater tables.

  14. On optimum temperature conditions for operation of portable aliminum-air batteries

    Directory of Open Access Journals (Sweden)

    Vlasenko Maxim

    2017-01-01

    Full Text Available For construction of portable aluminium-air batteries (AABs for field applications the data on performance of such batteries at low temperatures are necessary. Such experimental data are presented in this article. Lower temperature limit for effective operation of portable AABs is estimated. Possibility of AABs self-heating to the desired temperature is also considered.

  15. Low-temperature thermal energy storage program annual operating plan

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, H. W.; Eissenberg, D. M.

    1979-01-01

    The LTTES program operating plans for FY 1978 are described in terms of general program objectives and the technical activities being implemented to achieve these objectives. The program structure provides emphasis on several principal thrusts; namely, seasonal thermal storage, daily/short-term thermal storage, and waste heat recovery and reuse. A work breakdown structure (WBS) organizes the efforts being carried out in-house or through subcontract within each thrust area. Fiscal data are summarized in respect to thrust area, individual efforts, and funding source.

  16. Effects of Operating Temperatures and Accelerated Environmental Ageing on the Mechanical Properties of a Glass-Vinylester Composite

    Science.gov (United States)

    Klasztorny, M.; Nycz, D. B.; Romanowski, R. K.; Gotowicki, P.; Kiczko, A.; Rudnik, D.

    2017-07-01

    Experimental identification of the mechanical properties of a selected glass-vinylester structural composite is developed, performed, and analysed taking into account accelerated environmental ageing and three operating temperatures (-20, 20, and 55°C) corresponding to the operating temperature range for composite footbridges in the Central Europe. The main constituents of the composite fabricated using infusion technology are a bidirectional balanced stitched E-glass fabric and a flame retardant, vinylester resin. After homogenization, the composite reinforced with one fabric forms a single lamina and is modeled as a linear elastic-brittle orthotropic material. Full sets of material constants were identified for the initial and aged composites at the selected operating temperatures. The accelerated environmental ageing of the composite was performed on 4-layer symmetric laminate platelets protected with a 300-mm-thick gelcoat layer, using an ageing chamber and a relevant ageing programme. A comparative analysis was carried out in order to determine the effects of operating temperature and accelerated environmental ageing on the material constants of the GFRP composite. It is found that the composite tested can be modeled as a linear elastic-brittle orthotropic material to the level of 20% of its strength in each strength test. The impact of the accelerated environmental ageing and operating temperature in the range from -20 to 55°C on the elastic/strength/ultimate strain constants of the selected E-glass/vinylester composite can be significant and different for individual constants.

  17. Miniature cryocooler developments for high operating temperatures at Thales Cryogenics

    Science.gov (United States)

    Arts, R.; Martin, J.-Y.; Willems, D.; Seguineau, C.; Van Acker, S.; Mullié, J. C.; Göbel, A.; Tops, M.; Le Bordays, J.; Etchanchu, T.; Benschop, A. A. J.

    2015-05-01

    In recent years there has been a drive towards miniaturized cooled IDCA solutions for low-power, low-mass, low-size products (SWaP). To support this drive, coolers are developed optimized for high-temperature, low heat load dewar-detector assemblies. In this paper, Thales Cryogenics development activities supporting SWaP are presented. Design choices are discussed and compared to various key requirements. Trade-off analysis results are presented on drive voltage, cold finger definition (length, material, diameter and sealing concept), and other interface considerations, including cold finger definition. In parallel with linear and rotary cooler options, designs for small-size high-efficiency drive electronics based on state-of-the-art architectures are presented.

  18. Determinants of the VDU operator's well-being

    NARCIS (Netherlands)

    Pot, F.D.; Padmos, P.; Brouwers, A.A.F.

    1987-01-01

    Patterns of complaints of VDU operators have been studied in relation to work organization, workplace ergonomics and operators' eye quality. Host subjects worked on data entry and word processing. The percentage of working day with VDU (VDUTIME) varied widely among subjects. The relations found were

  19. Verilog-A Device Models for Cryogenic Temperature Operation of Bulk Silicon CMOS Devices

    Science.gov (United States)

    Akturk, Akin; Potbhare, Siddharth; Goldsman, Neil; Holloway, Michael

    2012-01-01

    Verilog-A based cryogenic bulk CMOS (complementary metal oxide semiconductor) compact models are built for state-of-the-art silicon CMOS processes. These models accurately predict device operation at cryogenic temperatures down to 4 K. The models are compatible with commercial circuit simulators. The models extend the standard BSIM4 [Berkeley Short-channel IGFET (insulated-gate field-effect transistor ) Model] type compact models by re-parameterizing existing equations, as well as adding new equations that capture the physics of device operation at cryogenic temperatures. These models will allow circuit designers to create optimized, reliable, and robust circuits operating at cryogenic temperatures.

  20. Determinants and nature of intramuscular temperature changes during cold therapy.

    Science.gov (United States)

    Lowdon, B J; Moore, R J

    1975-10-01

    The purpose of this study was to examine the intramuscular temperature response during an ice massage treatment. In addition, the effect of subcutaneous tissue thickness and limb circumference on temperature changes was investigated. Intramuscular temperature was measured by intramuscular thermocouples each minute during ice massage treatments of five, ten and fifteen minutes. It was shown that ice massage produces a significant drop in intramuscular temperature. However, there was no significant difference in temperature change after five minutes of treatment. In addition it was shown that there is a high multiple correlation between logarithmic time, subcutaneous tissue thickness, limb circumference, and intramuscular temperature change.

  1. Climate change and temperature-dependent sex determination in reptiles.

    OpenAIRE

    Janzen, F. J.

    1994-01-01

    Despite increasing concern over the possible impact of global temperature change, there is little empirical evidence of direct temperature effects on biotic interactions in natural systems. Clear assessment of the ecological and evolutionary impact of changing climatic temperature requires a natural system in which populations exhibit a direct unambiguous fitness response to thermal fluctuation. I monitored nests of a population of painted turtles (Chrysemys picta) with temperature-dependent ...

  2. Determination of optimum processing temperature for transformation of glyceryl monostearate.

    Science.gov (United States)

    Yajima, Toshio; Itai, Shigeru; Takeuchi, Hirofumi; Kawashima, Yoshiaki

    2002-11-01

    The purpose of this study was to clarify the mechanism of transformation from alpha-form to beta-form via beta'-form of glyceryl monostearate (GM) and to determine the optimum conditions of heat-treatment for physically stabilizing GM in a pharmaceutical formulation. Thermal analysis repeated twice using a differential scanning calorimeter (DSC) were performed on mixtures of two crystal forms. In the first run (enthalpy of melting: DeltaH1), two endothermic peaks of alpha-form and beta-form were observed. However, in the second run (enthalpy of melting: DeltaH2), only the endothermic peak of the alpha-form was observed. From a strong correlation observed between the beta-form content in the mixture of alpha-form and beta-form and the enthalpy change, (DeltaH1-DeltaH2)/DeltaH2, beta-form content was expressed as a function of the enthalpy change. Using this relation, the stable beta-form content during the heat-treatment could be determined, and the maximum beta-form content was obtained when the heat-treatment was carried out at 50 degrees C. An inflection point existed in the time course of transformation of alpha-form to beta-form. It was assumed that almost all of alpha-form transformed to beta'-form at this point, and that subsequently only transformation from beta'-form to beta-form occurred. Based on this aspect, the transformation rate equations were derived as consecutive reaction. Experimental data coincided well with the theoretical curve. In conclusion, GM was transformed in the consecutive reaction, and 50 degrees C was the optimum heat-treatment temperature for transforming GM from the alpha-form to the stable beta-form.

  3. Occupant Responses and Office Work Performance in Environments with Moderately Drifting Operative Temperatures (RP-1269)

    DEFF Research Database (Denmark)

    Kolarik, Jakub; Toftum, Jørn; Olesen, Bjarne W.;

    2009-01-01

    Fifty-two experimental subjects (50% female) were seated in a climate chamber and exposed to operative temperature ramps with different slopes, directions, and durations during two related experiments. The first experiment covered a temperature range of 22°C–26.8°C (71.6°F–80.2°F) and subjects wo...

  4. High temperature brushless DC motor system and its operation mode control

    Institute of Scientific and Technical Information of China (English)

    邹继斌; 胡建辉; 徐永向

    2001-01-01

    The high temperature ( 175 ℃ ) operation of a motor spells out special requirements for control algorithms, materials and elements. The stability of motor characteristic is guaranteed by the digital control strategy. Constant velocity operation is achieved by phase-locked loop ( PLL), and constant power operation is achieved by a current-restricting circuit. A motor for constant speed and constant power operation has been built and the speed control system is tuned by MATLAB simulation. Experimental and simulation results for operation mode control of brushless DC motor are presented.

  5. Experimental determination of monoethanolamine protonation constant and its temperature dependency

    Directory of Open Access Journals (Sweden)

    Ma’mun Sholeh

    2017-01-01

    Full Text Available Carbon dioxide as one of the major contributors to the global warming problem is produced in large quantities by many important industries and its emission seems to rise from year to year. Aminebased absorption is one of the methods to capture CO2 from its sources. As a reactive system, mass transfer and chemical reaction take place simultaneously. In a vapor-liquid equilibrium model for the CO2-amine-water system, some parameters such as mass transfer coefficients and chemical equilibrium constants need to be known. However, some parameters could be determined experimentally and the rests could be regressed from the model. The protonation constant (pKa, as one of the model parameters, could then be measured experimentally. The purpose of this study is to measure the pKa of monoethanolamine (MEA at a range of temperatures from 303 to 330K by a potentiometric titration method. The experimental data obtained were in a good agreement with the literature data. The pKa data from this work together with those from the literature were then correlated in an empirical correlation to be used for future research.

  6. Parametric Characterization of Reformate-operated PBI-based High Temperature PEM Fuel Cell Stack

    DEFF Research Database (Denmark)

    Sahlin, Simon Lennart

    2017-01-01

    This paper presents an experimental characterization of a HT-PEMFC short stack performed by means of impedance spectroscopy. Selected operating parameters; temperature, stoichiometry and reactant compositions were varied to investigate their effects on a reformate operated stack. Polarization...

  7. On the operation of silicon photomultipliers at temperatures of 1–4 kelvin

    Energy Technology Data Exchange (ETDEWEB)

    Achenbach, P., E-mail: patrick@kph.uni-mainz.de [Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz (Germany); Biroth, M., E-mail: biroth@kph.uni-mainz.de [Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz (Germany); Downie, E. [Physics Department, George Washington University, Washington DC (United States); Thomas, A. [Institut für Kernphysik, Johannes Gutenberg-Universität, Mainz (Germany)

    2016-07-11

    SiPM operation at cryogenic temperatures fails for many common devices. A particular type from Zecotek with deep channels in the silicon substrate instead of quenching resistors was tested at liquid helium temperature. Two similar types were thoroughly characterized from room temperature down to liquid nitrogen temperature by illuminating them with low light levels. At cryogenic temperatures the SiPMs show an unchanged rise-time and a fast recovery time, practically no after-pulses, and exhibit no increased cross-talk probability. Charge collection spectra were measured to extract the pixel gain and its variation, both comparable to room temperature at the same over-voltage. The quenching resistance was decreased at cryogenic temperature. It was found possible to use the characterized devices at temperatures of 1–4 K for the read-out of a target at the Mainz Microtron in Germany.

  8. Determination of Model Kinetics for Forced Unsteady State Operation of Catalytic CH4 Oxidation

    Directory of Open Access Journals (Sweden)

    Effendy Mohammad

    2016-01-01

    Full Text Available The catalytic oxidation of methane for abating the emission vented from coal mine or natural gas transportation has been known as most reliable method. A reverse flow reactor operation has been widely used to oxidize this methane emission due to its capability for autothermal operation and heat production. The design of the reverse flow reactor requires a proper kinetic rate expression, which should be developed based on the operating condition. The kinetic rate obtained in the steady state condition cannot be applied for designing the reactor operated under unsteady state condition. Therefore, new approach to develop the dynamic kinetic rate expression becomes indispensable, particularly for periodic operation such as reverse flow reactor. This paper presents a novel method to develop the kinetic rate expression applied for unsteady state operation. The model reaction of the catalytic methane oxidation over Pt/-Al2O3 catalyst was used with kinetic parameter determined from laboratory experiments. The reactor used was a fixed bed, once-through operation, with a composition modulation in the feed gas. The switching time was set at 3 min by varying the feed concentration, feed flow rate, and reaction temperature. The concentrations of methane in the feed and product were measured and analysed using gas chromatography. The steady state condition for obtaining the kinetic rate expression was taken as a base case and as a way to judge its appropriateness to be applied for dynamic system. A Langmuir-Hinshelwood reaction rate model was developed. The time period during one cycle was divided into some segments, depending on the ratio of CH4/O2. The experimental result shows that there were kinetic regimes occur during one cycle: kinetic regime controlled by intrinsic surface reaction and kinetic regime controlled by external diffusion. The kinetic rate obtained in the steady state operation was not appropriate when applied for unsteady state operation

  9. High Temperature Electrolysis 4 kW Experiment Design, Operation, and Results

    Energy Technology Data Exchange (ETDEWEB)

    J.E. O' Brien; X. Zhang; K. DeWall; L. Moore-McAteer; G. Tao

    2012-09-01

    This report provides results of long-term stack testing completed in the new high-temperature steam electrolysis multi-kW test facility recently developed at INL. The report includes detailed descriptions of the piping layout, steam generation and delivery system, test fixture, heat recuperation system, hot zone, instrumentation, and operating conditions. This facility has provided a demonstration of high-temperature steam electrolysis operation at the 4 kW scale with advanced cell and stack technology. This successful large-scale demonstration of high-temperature steam electrolysis will help to advance the technology toward near-term commercialization.

  10. Power Generation by Zinc Antimonide Thin Film under Various Load Resistances at its Critical Operating Temperature

    DEFF Research Database (Denmark)

    Mir Hosseini, Seyed Mojtaba; Rezaniakolaei, Alireza; Rosendahl, Lasse Aistrup

    thin films operating under different load resistances at around its critical operating temperature, 400 ᵒC. The thermoelement is subjected to constant hot side temperature and to room temperature at the cold junction in order to measure the thin film TEG’s sample performance. The nominal loads equal......Thermoelectric generators (TEGs) use the Seebeck effect in semiconductors for direct conversion of heat to electrical energy. Zinc antimonide films were deposited on polished fused silica substrates by co-sputtering method in Aarhus University. This study focuses on stability of zinc antimonide...

  11. The Successful Operation of Hole-type Gaseous Detectors at Cryogenic Temperatures

    CERN Document Server

    Pereiale, L; Iacobaeus, C; Francke, T; Lund-Jensen, B; Pavlopoulos, P; Picchi, P; Pietropaolo, F; Tokanai, F

    2004-01-01

    We have demonstrated that hole-type gaseous detectors, GEMs and capillary plates, can operate up to 77 K. For example, a single capillary plate can operate at gains of above 10E3 in the entire temperature interval between 300 until 77 K. The same capillary plate combined with CsI photocathodes could operate perfectly well at gains (depending on gas mixtures) of 100-1000. Obtained results may open new fields of applications for capillary plates as detectors of UV light and charge particles at cryogenic temperatures: noble liquid TPCs, WIMP detectors or LXe scintillating calorimeters and cryogenic PETs.

  12. Analysis of Geo-Temperature Restoration Performance under Intermittent Operation of Borehole Heat Exchanger Fields

    Directory of Open Access Journals (Sweden)

    Chaofeng Li

    2015-12-01

    Full Text Available Intermittent operation can improve the coefficient of performance (COP of a ground source heat pump (GSHP system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposition principle. The model takes into account the heat transfer along the borehole, thermal interference between BHEs, and the influence of groundwater flow. The accuracy of the model is validated through comparison with an experiment carried out under intermittent operation. The model makes it possible to analyze the geo-temperature restoration performance and its influencing factors, such as BHE spacing, heat flow rate, operation mode, and groundwater flow. The main conclusions of this work are as follows. The heat transfer along the borehole should be considered when analyzing the geo-temperature restoration performance. When the BHE spacing increases, the soil temperature change decreases and the heat recovery improves. Therefore, adequate borehole separation distance is essential in the case of a multiple BHE system with unbalanced load. The presence of groundwater flow is associated with interference between the BHEs, which should not be ignored. In the case of long-term operation, the groundwater flow is beneficial to the geo-temperature recovery process, even for downstream BHEs. Finally, a greater groundwater flux leads to a better geo-temperature recovery.

  13. On OMC-1 temperatures determined from methyl cyanide observations

    Science.gov (United States)

    Hollis, J. M.

    1982-01-01

    An analysis is performed on the J(k) = 12(k)-11(k) and 13(k)-12(k) transitions of methyl cyanide detected by other investigators in the direction of OMC-1. The original interpretation of those observations argues for the presence of two distinct temperature regions or possibly a temperature gradient within the cloud. The analysis presented here demonstrates that the observations of these particular molecular transitions are consistent with a single methyl cyanide emission region with a source kinetic temperature of 121.2 + or - 8.2 K and a molecular rotational temperature of 16.6 + or - 1.8 K.

  14. On OMC-1 temperatures determined from methyl cyanide observations

    Science.gov (United States)

    Hollis, J. M.

    1982-01-01

    An analysis is performed on the J(k) = 12(k)-11(k) and 13(k)-12(k) transitions of methyl cyanide detected by other investigators in the direction of OMC-1. The original interpretation of those observations argues for the presence of two distinct temperature regions or possibly a temperature gradient within the cloud. The analysis presented here demonstrates that the observations of these particular molecular transitions are consistent with a single methyl cyanide emission region with a source kinetic temperature of 121.2 + or - 8.2 K and a molecular rotational temperature of 16.6 + or - 1.8 K.

  15. Standard test method for determining liquidus temperature of immobilized waste glasses and simulated waste glasses

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These practices cover procedures for determining the liquidus temperature (TL) of nuclear waste, mixed nuclear waste, simulated nuclear waste, or hazardous waste glass in the temperature range from 600°C to 1600°C. This method differs from Practice C829 in that it employs additional methods to determine TL. TL is useful in waste glass plant operation, glass formulation, and melter design to determine the minimum temperature that must be maintained in a waste glass melt to make sure that crystallization does not occur or is below a particular constraint, for example, 1 volume % crystallinity or T1%. As of now, many institutions studying waste and simulated waste vitrification are not in agreement regarding this constraint (1). 1.2 Three methods are included, differing in (1) the type of equipment available to the analyst (that is, type of furnace and characterization equipment), (2) the quantity of glass available to the analyst, (3) the precision and accuracy desired for the measurement, and (4) candi...

  16. Operative environmental temperatures and basking behavior of the turtle Pseudemys scripta

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, K.M.; Spotila, J.R.; Standora, E.A.

    1983-01-01

    Operative environmental temperatures (T/sub e/, an index of the thermal environment) were measured for basking Pseudemys scripta in South Carolina. Operative environmental temperatures were good predictors of the basking behavior of P. scripta. Turtles in this study generally did not bask unless T/sub e/ was 28/sup 0/C (preferred body temperature) or higher. This demonstrated that basking was not a random behavior in respect to T/sub e/, and implicated thermoregulation as a major factor eliciting basking behavior. Operative environmental temperature was positively related to short-wave and total solar radiation as well as to air and substrate temperature. Substrate temperature was the best single predictor of T/sub e/. A multiple regression equation (T/sub e/ = 0.005R + 0.103T/sub a/ - 1.16 log V + 0.932T/sub s/ - 2.54, r/sup 2/ = .90, where R = total radiation in watts per square metre, T/sub a/ = air temperature in degrees Celsius, V = wind speed in metres per second, and T/sub s/ = substrate temperature in degrees Celsius) defines the relationship of T/sub e/ to microclimate variables. Movement of the sun through the day results in spatial variation in T/sub e/'s available to turtles and influences their location and basking behavior.

  17. Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2012-01-01

    Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

  18. Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2012-01-01

    Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

  19. Model for Determining Fixed Costs for the Winter Service Operation

    Directory of Open Access Journals (Sweden)

    Matija Glad

    2006-07-01

    Full Text Available From the season 2005!06 a new dynamic model for the operationof the Winter Service in the Republic of Croatia will beused. The old model was based on three levels of readiness, andthe roads were categorised primarily according to their administrativedistribution. The new dynamic model has three levelsof readiness, while the first level is further divided into two servicelevels. The road is classified to a certain readiness and servicelevel according to the traffic, climate and economic conditions.The new model splits the cost structure into fixed and variablecosts. The investor wants to keep the fixed costs at a minimal/eve~ which will guarantee proper readiness for quick intervention.The investor wants to ensure a technological infrastructurefor quality cleaning of roads is created. The capitalcompanies want larger fixed costs to ensure certain profit, anddefined fixed costs enable them to asses the profitability of theWinter Service operation. Such structure fonils the followingrelationship: in mild winters the capital companies "profit" andthe investor "loses", and vice versa for cold winters. Mathematically,such relationship should be treated as a finite strategictwo-player game.This paper will show the model needed to forecast fixedcosts in the new dynamic model for operation of Winter Ser·vice, through consideration of connection of linear programmingand the matrix game theory, to study the problem in parallel,from the standpoint of both players.

  20. Determinant of twisted chiral Dirac Operator on the Lattice

    OpenAIRE

    Fosco, C. D.; Randjbar-Daemi, S.

    1995-01-01

    Using the overlap formulation, we calculate the fermionic determinant on the lattice for chiral fermions with twisted boundary conditions in two dimensions. When the lattice spacing tends to zero we recover the results of the usual string-theory continuum calculations.

  1. Temperature Adaptation Markedly Determines Evolution within the Genus Saccharomyces▿

    Science.gov (United States)

    Salvadó, Z.; Arroyo-López, F. N.; Guillamón, J. M.; Salazar, G.; Querol, A.; Barrio, E.

    2011-01-01

    The present study uses a mathematical-empirical approach to estimate the cardinal growth temperature parameters (Tmin, the temperature below which growth is no longer observed; Topt, the temperature at which the μmax equals its optimal value; μopt, the optimal value of μmax; and Tmax, the temperature above which no growth occurs) of 27 yeast strains belonging to different Saccharomyces and non-Saccharomyces species. S. cerevisiae was the yeast best adapted to grow at high temperatures within the Saccharomyces genus, with the highest optimum (32.3°C) and maximum (45.4°C) growth temperatures. On the other hand, S. kudriavzevii and S. bayanus var. uvarum showed the lowest optimum (23.6 and 26.2°C) and maximum (36.8 and 38.4°C) growth temperatures, respectively, confirming that both species are more psychrophilic than S. cerevisiae. The remaining Saccharomyces species (S. paradoxus, S. mikatae, S. arboricolus, and S. cariocanus) showed intermediate responses. With respect to the minimum temperature which supported growth, this parameter ranged from 1.3 (S. cariocanus) to 4.3°C (S. kudriavzevii). We also tested whether these physiological traits were correlated with the phylogeny, which was accomplished by means of a statistical orthogram method. The analysis suggested that the most important shift in the adaptation to grow at higher temperatures occurred in the Saccharomyces genus after the divergence of the S. arboricolus, S. mikatae, S. cariocanus, S. paradoxus, and S. cerevisiae lineages from the S. kudriavzevii and S. bayanus var. uvarum lineages. Finally, our mathematical models suggest that temperature may also play an important role in the imposition of S. cerevisiae versus non-Saccharomyces species during wine fermentation. PMID:21317255

  2. Assessment of the use of temperature-sensitive microchips to determine core body temperature in goats.

    Science.gov (United States)

    Torrao, N A; Hetem, R S; Meyer, L C R; Fick, L G

    2011-03-26

    Body temperature was measured at five different body sites (retroperitoneum, groin, semimembranosus muscle, flank and shoulder) using temperature-sensitive microchips implanted in five female goats, and compared with the core body and rectal temperatures. Body temperature was measured while the goats were kept in different ambient temperatures, with and without radiant heat, as well as during a fever induced experimentally by injection of bacterial lipopolysaccharide. Bland-Altman limit of agreement analysis was used to compare the temperature measurements at the different body sites during the different interventions. Temperatures measured by the microchip implanted in the retroperitoneum showed the closest agreement (mean 0.2 °C lower) with core and rectal temperatures during all interventions, whereas temperatures measured by the microchips implanted in the groin, muscle, flank and shoulder differed from core body temperature by up to 3.5 °C during the various interventions.

  3. Effects of temperature on flood forecasting: analysis of an operative case study in Alpine basins

    Directory of Open Access Journals (Sweden)

    A. Ceppi

    2013-04-01

    Full Text Available In recent years the interest in the forecast and prevention of natural hazards related to hydro-meteorological events has increased the challenge for numerical weather modelling, in particular for limited area models, to improve the quantitative precipitation forecasts (QPF for hydrological purposes. After the encouraging results obtained in the MAP D-PHASE Project, we decided to devote further analyses to show recent improvements in the operational use of hydro-meteorological chains, and above all to better investigate the key role played by temperature during snowy precipitation. In this study we present a reanalysis simulation of one meteorological event, which occurred in November 2008 in the Piedmont Region. The attention is focused on the key role of air temperature, which is a crucial feature in determining the partitioning of precipitation in solid and liquid phase, influencing the quantitative discharge forecast (QDF into the Alpine region. This is linked to the basin ipsographic curve and therefore by the total contributing area related to the snow line of the event. In order to assess hydrological predictions affected by meteorological forcing, a sensitivity analysis of the model output was carried out to evaluate different simulation scenarios, considering the forecast effects which can radically modify the discharge forecast. Results show how in real-time systems hydrological forecasters have to consider also the temperature uncertainty in forecasts in order to better understand the snow dynamics and its effect on runoff during a meteorological warning with a crucial snow line over the basin. The hydrological ensemble forecasts are based on the 16 members of the meteorological ensemble system COSMO-LEPS (developed by ARPA-SIMC based on the non-hydrostatic model COSMO, while the hydrological model used to generate the runoff simulations is the rainfall–runoff distributed FEST-WB model, developed at Politecnico di Milano.

  4. Experimentally determined temperature thresholds for Arctic plankton community metabolism

    Science.gov (United States)

    Holding, J. M.; Duarte, C. M.; Arrieta, J. M.; Vaquer-Suyner, R.; Coello-Camba, A.; Wassmann, P.; Agustí, S.

    2013-01-01

    Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 °C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions based on the metabolic theory of ecology assume that temperature increase will enhance metabolic rates and thus both the rate of primary production and respiration will increase. However, these predictions do not consider the specific metabolic balance of the communities. We tested, experimentally, the response of Arctic plankton communities to seawater temperature spanning from 1 °C to 10 °C. Two types of communities were tested, open-ocean Arctic communities from water collected in the Barents Sea and Atlantic influenced fjord communities from water collected in the Svalbard fjord system. Metabolic rates did indeed increase as suggested by metabolic theory, however these results suggest an experimental temperature threshold of 5 °C, beyond which the metabolism of plankton communities shifts from autotrophic to heterotrophic. This threshold is also validated by field measurements across a range of temperatures which suggested a temperature 5.4 °C beyond which Arctic plankton communities switch to heterotrophy. Barents Sea communities showed a much clearer threshold response to temperature manipulations than fjord communities.

  5. Experimentally determined temperature thresholds for Arctic plankton community metabolism

    Directory of Open Access Journals (Sweden)

    J. M. Holding

    2013-01-01

    Full Text Available Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 °C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions based on the metabolic theory of ecology assume that temperature increase will enhance metabolic rates and thus both the rate of primary production and respiration will increase. However, these predictions do not consider the specific metabolic balance of the communities. We tested, experimentally, the response of Arctic plankton communities to seawater temperature spanning from 1 °C to 10 °C. Two types of communities were tested, open-ocean Arctic communities from water collected in the Barents Sea and Atlantic influenced fjord communities from water collected in the Svalbard fjord system. Metabolic rates did indeed increase as suggested by metabolic theory, however these results suggest an experimental temperature threshold of 5 °C, beyond which the metabolism of plankton communities shifts from autotrophic to heterotrophic. This threshold is also validated by field measurements across a range of temperatures which suggested a temperature 5.4 °C beyond which Arctic plankton communities switch to heterotrophy. Barents Sea communities showed a much clearer threshold response to temperature manipulations than fjord communities.

  6. Effects of operation temperature on thermal expansion and main parameters of radial ball bearings

    Directory of Open Access Journals (Sweden)

    Mitrović Radivoje M.

    2015-01-01

    Full Text Available The research of influence of operation temperature on the thermal expansion and main parameters of radial ball bearings is presented in this paper. The main bearing parameters are identified in accordance with the increasing requests concerning stability and load capacity. A series of Finite Element Analyses is performed for quasi-static analysis of all identified bearing parameters during contact period in referent temperature. Then, the dependence of bearing material characteristics on the operation temperature is discussed. Few series of Finite Element Analyses are performed for a particular radial ball bearing type, with characteristics in accordance with manufacturer specifications, for several operation temperatures. These two problems analyses include consideration of relation between the initial radial clearance, thermal expansion strains and contact deformations of the parts of the bearing assembly. The results for radial ball bearing parameters are monitored during a ball contact period for different temperatures and the appropriate discussion and conclusions are given. The conclusions about the contribution of developed procedure in defining the optimum operation temperature range are shown. [Projekat Ministarstva nauke Republike Srbije, br. TR 35029 i br. OI 174001

  7. Operation of high- Tc SFQ devices at near liquid nitrogen temperature

    Science.gov (United States)

    Kim, Y. H.; Kang, J. H.; Lee, J. M.; Hahn, T. S.; Choi, S. S.; Park, S. J.

    1997-02-01

    As the operating temperature of the SFQ logic circuits gets higher by using high- Tc superconductors, the effect of noise on switching a Josephson junction to the voltage state becomes more important. In this paper, we report our work on high- Tc SFQ RS flip-flop which was made with YBCO thin film deposited on a SrTiO 3 bi-crystal. The circuit operated correctly at 71 K over the 200 computer-generated clock cycles without making errors, where a reset or a set operation was made over one clock cycle. Good agreement between the measured data and the calculation based on the thermal activation theory was obtained. The effective noise temperature used to fit the data was much higher than the physical temperature. This could be due to the instrument noise. Improvement in the measurement set-up might reduce the effective noise temperature. Also our measurement results indicate that the elevation of the operating temperature near the liquid nitrogen temperature may not affect the margin of the circuit.

  8. Experimental Determination of Temperature During Rotary Friction Welding of AA1050 Aluminum with AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Eder Paduan Alves

    2012-03-01

    Full Text Available The purpose of this study was the temperature monitoring at bonding interface during the rotary friction welding process of dissimilar materials: AA1050 aluminum with AISI 304 stainless steel. As it is directly related to the mechanical strenght of the junction, its experimental determination in real time is of fundamental importance for understanding and characterizing the main process steps, and the definition and optimization of parameters. The temperature gradients were obtained using a system called Thermocouple Data-Logger, which allowed monitoring and recording data in real-time operation. In the graph temperature versus time obtained, the heating rates, cooling were analyzed, and the maximum temperature was determined that occurred during welding, and characterized every phases of the process. The efficiency of this system demonstrated by experimental tests and the knowledge of the temperature at the bonding interface open new lines of research to understand the process of friction welding.

  9. Determination of plutonium temperature using the special trans functions theory

    Directory of Open Access Journals (Sweden)

    Perović Slavica M.

    2010-01-01

    Full Text Available The problem of estimating plutonium temperature by an iterative procedure based on the special trans functions theory has been studied in some detail. In theory, the differential linear plutonium temperature equation can be effectively reduced to a non-linear functional transcendental equation solvable by special trans functions theory. This approach is practically invariant under the starting plutonium temperature value. This is significant, because the said iterative special trans functions theory does not depend on the password data of the plutonium cargo. Obtained numerical results and graphical simulations confirm the applicability of such approach.

  10. Temperatures and interval geothermal-gradient determinations from wells in National Petroleum Reserve in Alaska

    Science.gov (United States)

    Blanchard, D.C.; Tailleur, I.L.

    1982-01-01

    Temperature and related records from 28 wells in the National Petroleum Reserve in Alaska (NPRA) although somewhat constrained from accuracy by data gathering methods, extrapolate to undisturbed formation temperatures at specific depths below permafrost, and lead to calculated geothermal gradients between these depths. Tabulation of the results show that extrapolated undisturbed temperatures range from a minimum of 98?F (37?C) at 4,000 feet (1,220 m) to a maximum of 420?F (216?C) at 20,260 feet (6,177 m) and that geothermal gradients range from 0.34?F/100' (6?C/km) between 4,470 feet to 7,975 feet (Lisburne (1) and 3.15?F/100? (57?C/km) between 6,830 feet to 7,940 feet (Drew Point #1). Essential information needed for extrapolations consists of: time-sequential 'bottom-hole' temperatures during wire-line logging of intermediate and deep intervals of the bore hole; the times that circulating drilling fluids had disturbed the formations; and the subsequent times that non-circulating drilling fluids had been in contact with the formation. In several wells presumed near direct measures of rock temperatures recorded from formation fluids recovered by drill stem tests (DST) across thin (approx. 10-20 foot) intervals are made available. We believe that the results approach actual values close enough to serve as approximations of the thermal regimes in appropriate future investigations. Continuous temperature logs obtained at the start and end of final logging operations, conductivity measurements, and relatively long-term measurements of the recovery from disturbance at shallow depths in many of the wells will permit refinements of our values and provide determination of temperatures at other depths.

  11. On the potential of solar cells to efficiently operate at high temperature

    Science.gov (United States)

    Zeitouny, Joya; Lalau, Noémie; Katz, Eugene A.; Dollet, Alain; Vossier, Alexis

    2017-09-01

    The development of high temperature CPV/thermal (CSP) hybrid systems appears to be a promising route to improve the overall solar to electricity conversion efficiency. Moreover, such systems would not only use the residual heat stemming from the unconverted fraction of the incident solar radiation in PV cells, but they would also provide the advantage of storing energy as heat. However, the performances of such hybrid systems depend strongly on the temperature of the thermal receivers which are only effective at high temperatures (typically above 250°C) while solar cells typically operate at temperatures close to ambient. An appropriate strategy is to make PV cells efficiently operate at temperature levels significantly exceeding the normal range of temperatures for which they are commonly designed. The degradation of electrical performance associated with high working temperature is less pronounced when the cell is submitted to high sunlight concentrations. An efficient photovoltaic conversion at temperature levels exceeding the ambient may however require significant modifications in the architecture of the cells. In this work, we assessed the feasibility of this strategy by studying the electrical properties as well as the overall efficiency of the PV/CSP system at different temperatures and sunlight illuminations.

  12. Enlargements of Monotone Operators Determined by Representing Function

    Directory of Open Access Journals (Sweden)

    M. Rezaei

    2012-03-01

    Full Text Available In this paper, we study a new enlargement of subdifferential for any proper lower semicontinuous function. We know that ε-subdifferential of any proper lower semicontinuous function is an enlargement of its subfifferential and any point from the graph of ε- subdifferential can be approximated by a point from the graph of sub- fifferential. This nice property, apart from its theoretical importance, gives also the possibility to use the enlargement of subdifferentials in finding approximate solutions of inclusions determined by subdifferentials. We define a new enlargement and observe, in the case subdifferentials, the relation between this new enlargement and the ε- subdifferentia

  13. Research data supporting "Determining pressure-temperature phase diagrams of materials"

    OpenAIRE

    Baldock, Robert J.N.; Partay, Livia B.; Bartok, Albert P.; Payne, Michael C.; Csanyi, Gabor

    2016-01-01

    Pressure-temperature phase diagrams of the Lennard-Jones system, aluminium and nickel titanium as reported in the paper "Determining pressure-temperature phase diagrams of materials", together with example nested sampling output for aluminium and nickel titanium calculations. This research data supports “Determining pressure-temperature phase diagrams of materials” which has been published in “Physical Review B”. Research data supporting “Determining pressure-temperature phase diagrams...

  14. The effect of the operating temperatures and the solubility of paraffin on wax deposition

    Energy Technology Data Exchange (ETDEWEB)

    Han, Shanpeng [Beijing Key Laboratory for Urban Oil and Gas Distribution Technology, China University of Petroleum (China); Huang, Zhenyu; Fogler, H. Scott [Department of Chemical Engineering, University of Michigan (United States)], email: sfogler@umich.edu; Hoffmann, Rainer [Heroya Research Centre, Statoil ASA (Norway)

    2010-07-01

    Over time, wax deposits accumulate in subsea pipelines, generating major flow problems for the petroleum industry. Different flow loop experiments with various operating temperatures were conducted. The wax can be stimulated at different axial positions in the subsea pipelines depending on the temperature. In this paper, a series of experiments were carried out based on different inlet temperatures and a model was applied. The experimental results concluded that deposit thickness increases as the temperature at the inlet decreases. These results were contradictory of previous studies. To further examine this inconsistency in the model, theoretical analysis was conducted using the fundamentals of transport phenomena, both oil and crude oil were used. According to the model, the temperature gradient at the interface and change of wax solubility are the two leading causes which contribute to wax deposits. In conclusion, the paper finds that no generalization can be made about the inlet temperature without considering other factors.

  15. Broad negative thermal expansion operation-temperature window in antiperovskite manganese nitride with small crystallites

    Institute of Scientific and Technical Information of China (English)

    Jie Tan[1,2; Rongjin Huang[1; Wei Wang[1; Wen Li[1,2; YuqiangZhao[1,2; Shaopeng Li[1,2; Yemao Han[1,2; Chuanjun Huang[1; Laifeng Li[1

    2015-01-01

    Using spark plasma sintering (SPS), Mn3Cu0.6Ge0.4N crystallites have been fabricated with different crystallite sizes, and their magnetic properties and thermal behaviors were systemically investigated. With decreasing crystallite size, the magnetic transition becomes increasingly slow, accompanied by broadening of the negative thermal expansion (NTE) operation-temperature window. The NTE operation-temperature window for the 12-nm crystallite sample reaches at 140 K, which is about 75% larger than that of the 74-nm crystallite sample. The magnetic properties and NTE operation-temperature window can be tuned by varying the crystallite size. This discovery will promote an even wider range of practical applications in precision devices.

  16. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature.

    Science.gov (United States)

    Schmuck, S; Fessey, J; Gerbaud, T; Alper, B; Beurskens, M N A; de la Luna, E; Sirinelli, A; Zerbini, M

    2012-12-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.

  17. Evaluation of Artificial Neural Network-Based Temperature Control for Optimum Operation of Building Envelopes

    Directory of Open Access Journals (Sweden)

    Jin Woo Moon

    2014-11-01

    Full Text Available This study aims at developing an indoor temperature control method that could provide comfortable thermal conditions by integrating heating system control and the opening conditions of building envelopes. Artificial neural network (ANN-based temperature control logic was developed for the control of heating systems and openings at the building envelopes in a predictive and adaptive manner. Numerical comparative performance tests for the ANN-based temperature control logic and conventional non-ANN-based counterpart were conducted for single skin enveloped and double skin enveloped buildings after the simulation program was validated by comparing the simulation and the field measurement results. Analysis results revealed that the ANN-based control logic improved the indoor temperature environment with an increased comfortable temperature period and decreased overshoot and undershoot of temperatures outside of the operating range. The proposed logic did not show significant superiority in energy efficiency over the conventional logic. The ANN-based temperature control logic was able to maintain the indoor temperature more comfortably and with more stability within the operating range due to the predictive and adaptive features of ANN models.

  18. Improved cycling behavior of ZEBRA battery operated at intermediate temperature of 175 °C

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Lemmon, John P.; Sprenkle, Vincent L.

    2014-03-01

    Operation of the sodium-nickel chloride battery at temperatures below 200°C reduces cell degradation and improves cyclability. One of the main technical issues with operating this battery at intermediate temperatures such as 175°C is the poor wettability of molten sodium on β”-alumina solid electrolyte (BASE), which causes reduced active area and limits charging. In order to overcome the poor wettability of molten sodium on BASE at 175°C, a Pt grid was applied on the anode side of the BASE using a screen printing technique. Cells with their active area increased by metallized BASEs exhibited deeper charging and stable cycling behavior.

  19. Temperature limits for LMFBR fuel cladding under upset and emergency operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Govindarajan, S.; Chetal, S.C. [Indira Gandhi Centre for Atomic Research, Kalpakkam Tamilnadu (India). Nuclear Systems Division

    1996-07-01

    LMFBR fuel pin cladding tube is subjected to high transient temperatures during incidents such as pump trip, pump to grid plate pipe rupture etc. It is required to know temperature limits under such transient operating conditions for components involved while analyzing such incidents. A methodology for deriving such limits for fuel clad tube is worked out in this paper by making use of the transient damage correlation proposed by W.F. Brizes et. al.

  20. Mirror thermal noise in laser interferometer gravitational wave detectors operating at room and cryogenic temperature

    CERN Document Server

    Franc, Janyce; Flaminio, Raffaele; Nawrodt, Ronny; Martin, Iain; Cunningham, Liam; Cumming, Alan; Rowan, Sheila; Hough, James

    2009-01-01

    Mirror thermal noise is and will remain one of the main limitations to the sensitivity of gravitational wave detectors based on laser interferometers. We report about projected mirror thermal noise due to losses in the mirror coatings and substrates. The evaluation includes all kind of thermal noises presently known. Several of the envisaged substrate and coating materials are considered. The results for mirrors operated at room temperature and at cryogenic temperature are reported.

  1. Experimentally determined temperature thresholds for Arctic plankton community metabolism

    OpenAIRE

    J. M. Holding; Duarte, C. M.; Arrieta, J. M.; R. Vaquer-Sunyer; Coello-Camba, A.; P. Wassmann; S. Agustí

    2013-01-01

    Climate warming is especially severe in the Arctic, where the average temperature is increasing 0.4 C per decade, two to three times higher than the global average rate. Furthermore, the Arctic has lost more than half of its summer ice extent since 1980 and predictions suggest that the Arctic will be ice free in the summer as early as 2050, which could increase the rate of warming. Predictions based on the metabolic theory of ecology assume that temperature increase will enhance metabolic rat...

  2. Temperature and brain death determination: need for updated criteria

    Directory of Open Access Journals (Sweden)

    Michael A. Meyer

    2010-08-01

    Full Text Available For an excellent review on the diagnosis of brain death, the interested reader is directed to the review of Machado appearing in this journal; the author reviews all aspects of brain death and cites nine different references where the minimum temperature for brain death exams appear to have been at least 32°C. Given the new data listed above, it is clearly time for a reconsideration of the how we approach the exam for diagnosis of brain death – normal or near normal temperatures of 36°C and above are very reasonable starting points.

  3. (Modified) Fredholm Determinants for Operators with Matrix-Valued Semi-Separable Integral Kernels Revisited

    OpenAIRE

    Gesztesy, Fritz; Makarov, Konstantin A.

    2003-01-01

    We revisit the computation of (2-modified) Fredholm determinants for operators with matrix-valued semi-separable integral kernels. The latter occur, for instance, in the form of Green's functions associated with closed ordinary differential operators on arbitrary intervals on the real line. Our approach determines the (2-modified) Fredholm determinants in terms of solutions of closely associated Volterra integral equations, and as a result offers a natural way to compute such determinants. We...

  4. Optimization of the operation of a network of low temperature geothermal reservoirs

    OpenAIRE

    Hrannar Már Sigrúnarson 1975

    2013-01-01

    In 1930 the first low temperature geothermal reservoir was harvested in Reykjavik. In the decades that followed more reservoirs where harvested and in 1990 Nejsavellir power plant began operation and supplied hot water to Reykjavík. Today all hot water used in Reykjavík has it's source from low temperature geothermal reservoirs or power plants that heat up cold ground water with geothermal heat. Around Reykjavík there are four low temperature reservoirs and two power plants that produce water...

  5. 16nm planar process CMOS SRAM cell design: Analysis of Operating Voltage and Temperature Effect

    Directory of Open Access Journals (Sweden)

    Rohit Sharma

    2013-09-01

    Full Text Available Purpose: CMOS devices are scaling down to nano ranges resulting in increased process variations and short channel effects which not only affect the reliability of the device but also performance expectations. The SRAM design uses the smallest transistors possible and is also susceptible to reliability issues and process variations, making it an ideal benchmark circuit to compare the two technologies [1]. Low power static-random access memories (SRAM have become a critical component in modern VLSI systems. They occupy a large portion of area and accounts for a major component of power consumption in today’s VLSI circuits. In this paper we intend to analyse the performance of a traditional 6T SRAM cell of 16nm Complementary Metal Oxide Semiconductor (CMOS technology with change in Operating Voltage and Temperature. Aim: The aim of the paper is to study the effect of the SNM dependencies on the operating voltage and temperatureApproach: Conventional 6T SRAM are designed using predictive technology model developed by Arizona State University [2] of 16nm planar Low Power CMOS and variation of SNM with operating voltage and temperature are simulated and studied using hspice.Findings: Variations in the operating voltages and temperature strongly impact the stability of an SRAM cell at 16nm. Comparative study is done for predictive 16nm based conventional 6T SRAM cell by varying operating voltage and temperature. A methodology to select operating voltage is suggested which can be used in an early stage of a design cycle to optimise stability margins in nanometer regime

  6. Structural transformations and temperature state of rotating blades of E1893 alloy under operation

    Energy Technology Data Exchange (ETDEWEB)

    Pigrova, G.D.; Rybnikov, A.I.; Kryukov, I.I. [Polzunov Central Boiler and Turbine Institute, St. Petersburg (Russian Federation)

    1998-12-31

    The composition and quantity of different phase component of EI893 alloy after long term operation as base metal for rotating blades of gas turbines GT-6, GTN-9, GTK-10 and GT-100 types were studied. The obtained date were analysed with regard to the chemical composition of alloys and of initial condition of heat treatment. Data of metal phase analysis owned alter operation can provide the basis for evaluation of tempera field of rotating blades in the course of operation since structural condition of phase components and redistribution of alloying elements are being specified by temperature and in-service time. (orig.)

  7. Simulating potential structural and operational changes for Detroit Dam on the North Santiam River, Oregon, for downstream temperature management

    Science.gov (United States)

    Buccola, Norman L.; Rounds, Stewart A.; Sullivan, Annett B.; Risley, John C.

    2012-01-01

    Detroit Dam was constructed in 1953 on the North Santiam River in western Oregon and resulted in the formation of Detroit Lake. With a full-pool storage volume of 455,100 acre-feet and a dam height of 463 feet, Detroit Lake is one of the largest and most important reservoirs in the Willamette River basin in terms of power generation, recreation, and water storage and releases. The U.S. Army Corps of Engineers operates Detroit Dam as part of a system of 13 reservoirs in the Willamette Project to meet multiple goals, which include flood-damage protection, power generation, downstream navigation, recreation, and irrigation. A distinct cycle in water temperature occurs in Detroit Lake as spring and summer heating through solar radiation creates a warm layer of water near the surface and isolates cold water below. Controlling the temperature of releases from Detroit Dam, therefore, is highly dependent on the location, characteristics, and usage of the dam's outlet structures. Prior to operational changes in 2007, Detroit Dam had a well-documented effect on downstream water temperature that was problematic for endangered salmonid fish species, releasing water that was too cold in midsummer and too warm in autumn. This unnatural seasonal temperature pattern caused problems in the timing of fish migration, spawning, and emergence. In this study, an existing calibrated 2-dimensional hydrodynamic water-quality model [CE-QUAL-W2] of Detroit Lake was used to determine how changes in dam operation or changes to the structural release points of Detroit Dam might affect downstream water temperatures under a range of historical hydrologic and meteorological conditions. The results from a subset of the Detroit Lake model scenarios then were used as forcing conditions for downstream CE-QUAL-W2 models of Big Cliff Reservoir (the small reregulating reservoir just downstream of Detroit Dam) and the North Santiam and Santiam Rivers. Many combinations of environmental, operational, and

  8. 42 CFR 412.71 - Determination of base-year inpatient operating costs.

    Science.gov (United States)

    2010-10-01

    ... Costs § 412.71 Determination of base-year inpatient operating costs. (a) Base-year costs. (1) For each...) Modifications to base-year costs. Prior to determining the hospital-specific rate, the intermediary will adjust the hospital's estimated base-year inpatient operating costs, as necessary, to include...

  9. Determination of the temperature dependence of tungsten erosion

    Energy Technology Data Exchange (ETDEWEB)

    Maier, H., E-mail: Hans.Maier@ipp.mpg.de; Greuner, H.; Toussaint, U. von; Balden, M.; Böswirth, B.; Elgeti, S.

    2015-08-15

    We present the results of erosion measurements on actively cooled tungsten samples at quasi-constant surface temperature conditions performed in the high heat flux facility GLADIS. The samples were exposed to a H beam at a central power density of 10 MW/m{sup 2} up to a fluence of 10{sup 26} m{sup −2}. We observe a weak temperature dependence of the erosion yield. The data are compared with similar data obtained from loading with a H beam with He admixture. Both datasets are analysed in a probabilistic approach. We obtain activation energies of 0.04 eV and 0.06 eV for the cases with and without He, respectively.

  10. Determinants of outcome in operatively and non-operatively treated Weber-B ankle fractures

    NARCIS (Netherlands)

    E.M. van Schie- van der Weert; E.M.M. van Lieshout (Esther); M.R. de Vries (Mark); M. van der Elst (Maarten); T. Schepers (Tim)

    2012-01-01

    textabstractIntroduction: Treatment of ankle fractures is often based on fracture type and surgeon's individual judgment. Literature concerning the treatment options and outcome are dated and frequently contradicting. The aim of this study was to determine the clinical and functional outcome after A

  11. Room Temperature Operation of a Buried Heterostructure Photonic Crystal Quantum Cascade Laser

    CERN Document Server

    Peretti, R; Wolf, J M; Bonzon, C; Süess, M J; Lourdudoss, S; Metaferia, W; Beck, M; Faist, J

    2015-01-01

    We demonstrated room temperature operation of deep etched photonic crystal quantum cascade laser emitting around 8.5 micron. We fabricated buried heterostructure photonic crystals, resulting in single mode laser emission on a high order slow Bloch modes of the photonic crystal, between high symmetry points of the Brillouin.

  12. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability

  13. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability pr

  14. Monitoring operating temperature and supply voltage in achieving high system dependability

    NARCIS (Netherlands)

    Khan, Muhammad Aamir; Kerkhoff, Hans G.

    2013-01-01

    System dependability being a set of number of attributes, of which the important reliability, heavily depends on operating temperature and supply voltage. Any change beyond the designed specifications may change the system performance and could result in system reliability and hence dependability pr

  15. Ice formation in PEM fuel cells operated isothermally at sub-freezing temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mukundan, Rangachary [Los Alamos National Laboratory; Luhan, Roger W [Los Alamos National Laboratory; Davey, John R [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Hussey, Daniel S [NIST; Jacobson, David L [NIST; Arif, Muhammad [NIST

    2009-01-01

    The effect of MEA and GDL structure and composition on the performance of single-PEM fuel cells operated isothermally at subfreezing temperatures is presented. The cell performance and durability are not only dependent on the MEA/GDL materials used but also on their interfaces. When a cell is operated isothermally at sub-freezing temperatures in constant current mode, the water formation due to the current density initially hydrates the membrane/ionomer and then forms ice in the catalyst layer/GDL. An increase in high frequency resistance was also observed in certain MEAs where there is a possibility of ice formation between the catalyst layer and GDL leading to a loss in contact area. The total water/ice holding capacity for any MEA was lower at lower temperatures and higher current densities. The durability of MEAs subjected to multiple isothermal starts was better for LANL prepared MEAs as compared to commercial MEAs, and cloth GDLs when compared to paper GDLs. The ice formation was monitored using high-resolution neutron radiography and was found to be concentrated near the cathode catalyst layer. However, there was significant ice formation in the GDLs especially at the higher temperature ({approx} -10 C) and lower current density (0.02 A/cm{sup 2}) operations. These results are consistent with the longer-term durability observations that show more severe degradation at the lower temperatures.

  16. Power-feedwater temperature operating domain for Sbwr applying Monte Carlo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar M, L. A.; Quezada G, S.; Espinosa M, E. G.; Vazquez R, A.; Varela H, J. R.; Cazares R, R. I.; Espinosa P, G., E-mail: sequega@gmail.com [Universidad Autonoma Metropolitana, Unidad Iztapalapa, San Rafael Atlixco No. 186, Col. Vicentina, 09340 Mexico D. F. (Mexico)

    2014-10-15

    In this work the analyses of the feedwater temperature effects on reactor power in a simplified boiling water reactor (Sbwr) applying a methodology based on Monte Carlo simulation is presented. The Monte Carlo methodology was applied systematically to establish operating domain, due that the Sbwr are not yet in operation, the analysis of the nuclear and thermal-hydraulic processes must rely on numerical modeling, with the purpose of developing or confirming the design basis and qualifying the existing or new computer codes to enable reliable analyses. The results show that the reactor power is inversely proportional to the temperature of the feedwater, reactor power changes at 8% when the feed water temperature changes in 8%. (Author)

  17. Fast, computer supported experimental determination of absolute zero temperature at school

    OpenAIRE

    Pędziwiatr, Antoni T.; Bogacz, Bogdan

    2014-01-01

    A concept of absolute temperature is discussed and a simple method of determining absolute zero temperature is presented - based on gas thermometer coupled with pressure sensor and computer data acquisition system Coach. By constructing a pressure vs temperature plot for air and extrapolating it to zero pressure it is possible to obtain a reasonable value of absolute zero temperature. It is a convincing and straightforward method to enhance understanding the concept of temperature and suppor...

  18. Improved operation of graded-channel SOI nMOSFETs down to liquid helium temperature

    Science.gov (United States)

    Pavanello, Marcelo Antonio; de Souza, Michelly; Ribeiro, Thales Augusto; Martino, João Antonio; Flandre, Denis

    2016-11-01

    This paper presents the operation of Graded-Channel (GC) Silicon-On-Insulator (SOI) nMOSFETs at low temperatures down to liquid helium temperature in comparison to standard uniformly doped transistors. Devices from two different technologies have been measured and show that the mobility increase rate with temperature for GC SOI transistors is similar to uniformly doped devices for temperatures down to 90 K. However, at liquid helium temperature the rate of mobility increase is larger in GC SOI than in standard devices because of the different mobility scattering mechanisms. The analog properties of GC SOI devices have been investigated down to 4.16 K and show that because of its better transconductance and output conductance, an intrinsic voltage gain improvement with temperature is also obtained for devices in the whole studied temperature range. GC devices are also capable of reducing the impact ionization due to the high electric field in the drain region, increasing the drain breakdown voltage of fully-depleted SOI MOSFETs at any studied temperature and the kink voltage at 4.16 K.

  19. Structural parameters and X-ray Debye temperature determination study on copper-ferrite-aluminates

    Science.gov (United States)

    Lakhani, V. K.; Pathak, T. K.; Vasoya, N. H.; Modi, K. B.

    2011-03-01

    The compositional dependence of structural parameters and X-ray Debye temperature for CuAl xFe 2- xO 4 ( x = 0.0, 0.2, 0.4 and 0.6) spinel ferrite system has been studied by means of X-ray powder diffraction (XRD) patterns analysis at 300 K. The XRD data have been used to determine the lattice constant, X-ray density, distribution of cations among the tetrahedral and octahedral sites of spinel lattice, oxygen positional parameter, site radii, bond angle, bond length and interionic distances. The X-ray Debye temperatures have been determined from integrated intensities of selected Bragg reflections. It is found that Al 3+-substitution has marked influence on various parameters. A deficit of Cu 2+-cations at the octahedral sites of the spinel lattice leads to the absence of co-operative active Jahn-Teller distortion and the crystal structure retains into cubic. The increasing disagreement between observed and calculated intensities and reduction in intensity of diffracted beam with increasing Al-concentration have been explained based on preferred orientation and extinction effects. The effect of oxygen deficiency on intensity ratios of planes has been discussed in brief.

  20. High-Operating Temperature HgCdTe: A Vision for the Near Future

    Science.gov (United States)

    Lee, D.; Carmody, M.; Piquette, E.; Dreiske, P.; Chen, A.; Yulius, A.; Edwall, D.; Bhargava, S.; Zandian, M.; Tennant, W. E.

    2016-09-01

    We review recent advances in the HgCdTe material quality and detector performance achieved at Teledyne using molecular beam epitaxy growth and the double-layer planar hetero-junction (DLPH) detector architecture. By using an un-doped, fully depleted absorber, Teledyne's DLPH architecture can be extended for use in high operating temperatures and other applications. We assess the potential achievable performance for long wavelength infrared (LWIR) hetero-junction p-lightly-doped n or p-intrinsic- n (p-i-n) detectors based on recently reported results for 10.7 μm cutoff 1 K × 1 K focal plane arrays (FPAs) tested at temperatures down to 30 K. Variable temperature dark current measurements show that any Shockley-Read-Hall currents in the depletion region of these devices have lifetimes that are reproducibly greater than 100 ms. Under the assumption of comparable lifetimes at higher temperatures, it is predicted that fully-depleted background radiation-limited performance can be expected for 10- μm cutoff detectors from room temperature to well below liquid nitrogen temperatures, with room-temperature dark current nearly 400 times lower than predicted by Rule 07. The hetero-junction p-i-n diode is shown to have numerous other significant potential advantages including minimal or no passivation requirements for pBn-like processing, low 1/ f noise, compatibility with small pixel pitch while maintaining high modulation transfer function, low crosstalk and good quantum efficiency. By appropriate design of the FPA dewar shielding, analysis shows that dark current can theoretically be further reduced below the thermal equilibrium radiative limit. Modeling shows that background radiation-limited LWIR HgCdTe operating with f/1 optics has the potential to operate within √2 of background-limited performance at 215 K. By reducing the background radiation by 2/3 using novel shielding methods, operation with a single-stage thermo-electric-cooler may be possible. If the

  1. An Application of Two Experimental Modal Analysis Methods for the Determination of Operational Deflection Shapes

    Science.gov (United States)

    Kromulski, J.; Hojan, E.

    1996-10-01

    Two methods are presented for the determination of operational deflection shapes (ODSs). The first method allows one to determine the ODSs by measuring mechanical vibrations at test points of the operating machine (created by the forces occurring in the actual work cycle). The second method is based on the modal model of the machine, including the forces which occur in the operation process, and yields the operational modes of vibration. The forces introduced into the model are determined by methods of pseudo-inversion of the matrix of the spectral transmissibility functions of the mechanical system and the vector of operating vibrations. The determination of the forces involved is necessary for the definition of the paths of energy transfer and the analysis of the noise emitted by the mechanical system (machine).

  2. End-pumped 1.5 microm monoblock laser for broad temperature operation.

    Science.gov (United States)

    Schilling, Bradley W; Chinn, Stephen R; Hays, A D; Goldberg, Lew; Trussell, C Ward

    2006-09-01

    We describe a next-generation monoblock laser capable of a greater than 10 mJ, 1.5 microm output at 10 pulses/s (pps) over broad ambient temperature extremes with no active temperature control. The transmitter design is based on a Nd:YAG laser with a Cr4+ passive Q switch and intracavity potassium titanyl phosphate optical parametric oscillator. To achieve the repetition rate and efficiency goals of this effort, but still have wide temperature capability, the Nd:YAG slab is end pumped with a 12-bar stack of 100 W (each) diode bars. Different techniques for focusing the pump radiation into the 4.25 mmx4.25 mm end of the slab are compared, including a lensed design, a reflective concentrator, and a lens duct. A wide temperature operation (-20 degrees C to 50 degrees C) for each end-pumped configuration is demonstrated.

  3. Study of the operation temperature in the spin-exchange relaxation free magnetometer.

    Science.gov (United States)

    Fang, Jiancheng; Li, Rujie; Duan, Lihong; Chen, Yao; Quan, Wei

    2015-07-01

    We study the influence of the cell temperature on the sensitivity of the spin-exchange relaxation free (SERF) magnetometer and analyze the possibility of operating at a low temperature. Utilizing a 25 × 25 × 25 mm(3) Cs vapor cell with a heating temperature of 85 °C, which is almost half of the value of potassium, we obtain a linewidth of 1.37 Hz and achieve a magnetic field sensitivity of 55 fT/Hz(1/2) in a single channel. Theoretical analysis shows that fundamental sensitivity limits of this device with an active volume of 1 cm(3) could approach 1 fT/Hz(1/2). Taking advantage of the higher saturated vapor pressure, SERF magnetometer based on Cs opens up the possibility for low cost and portable sensors and is particularly appropriate for lower temperature applications.

  4. High performance shape memory effect in nitinol wire for actuators with increased operating temperature range

    Science.gov (United States)

    Casati, Riccardo; Biffi, Carlo Alberto; Vedani, Maurizio; Tuissi, Ausonio

    2014-07-01

    In this research, the high performance shape memory effect (HP-SME) is experimented on a shape memory NiTi wire, with austenite finish temperature higher than room temperature. The HP-SME consists in the thermal cycling of stress induced martensite and it allows achieving mechanical work higher than that produced by conventional shape memory actuators based on the heating/cooling of detwinned martensite. The Nitinol wire was able to recover about 5.5% of deformation under a stress of 600 MPa and to withstand about 5000 cycles before failure. HP-SME path increased the operating temperature of the shape memory actuator wire. Functioning temperatures higher than 100°C was reached.

  5. Flow and containment characteristics of an air-curtain fume hood operated at high temperatures.

    Science.gov (United States)

    Chen, Jia-Kun; Huang, Rong Fung; Hsin, Pei-Yi; Hsu, Ching Min; Chen, Chun-Wann

    2012-01-01

    The flow and leakage characteristics of the air-curtain fume hood under high temperature operation (between 100°C and 250°C) were studied. Laser-assisted flow visualization technique was used to reveal the hot plume movements in the cabinet and the critical conditions for the hood-top leakage. The sulfur hexafluoride tracer-gas concentration test method was employed to examine the containment spillages from the sash opening and the hood top. It was found that the primary parameters dominating the behavior of the flow field and hood performance are the sash height and the suction velocity as an air-curtain hood is operated at high temperatures. At large sash height and low suction velocity, the air curtain broke down and accompanied with three-dimensional flow in the cabinet. Since the suction velocity was low and the sash opening was large, the makeup air drawn down from the hood top became insufficient to counter act the rising hot plume. Under this situation, containment leakage from the sash opening and the hood top was observed. At small sash opening and high suction velocity, the air curtain presented robust characteristics and the makeup air flow from the hood top was sufficiently large. Therefore the containment leakages from the sash opening and the hood top were not observed. According to the results of experiments, quantitative operation sash height and suction velocity corresponding to the operation temperatures were suggested.

  6. S∧4 Reactor: Operating Lifetime and Estimates of Temperature and Burnup Reactivity Coefficients

    Science.gov (United States)

    King, Jeffrey C.; El-Genk, Mohamed S.

    2006-01-01

    The S∧4 reactor has a sectored, Mo-14%Re solid core for avoidance of single point failures in reactor cooling and Closed Brayton Cycle (CBC) energy conversion. The reactor is loaded with UN fuel, cooled with a He-Xe gas mixture at ~1200 K and operates at steady thermal power of 550 kW. Following a launch abort accident, the axial and radial BeO reflectors easily disassemble upon impact so that the bare reactor is subcriticial when submerged in wet sand or seawater and the core voids are filled with seawater. Spectral Shift Absorber (SSA) additives have been shown to increase the UN fuel enrichment and significantly reduce the total mass of the reactor. This paper investigates the effects of SSA additions on the temperature and burnup reactivity coefficients and the operational lifetime of the S∧4 reactor. SSAs slightly decrease the temperature reactivity feedback coefficient, but significantly increase the operating lifetime by decreasing the burnup reactivity coefficient. With no SSAs, fuel enrichment is only 58.5 wt% and the estimated operating lifetime is the shortest (7.6 years) with the highest temperature and burnup reactivity feedback coefficients (-0.2709 ¢/K and -1.3470 $/atom%). With europium-151 and gadolinium-155 additions, the enrichment (91.5 and 94 wt%) and operating lifetime (9.9 and 9.8 years) of the S∧4 reactor are the highest while the temperature and burnup reactivity coefficients (-0.2382 and -0.2447 ¢/K -0.9073 and 0.8502 $/atom%) are the lowest.

  7. Solar thermal collectors in polymeric materials: A novel approach towards higher operating temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Joao Farinha; Horta, Pedro; Carvalho, Maria Joao [INETI - Inst. Nacional de Engenharia Tecnologia e Inovacao, IP, Lisboa (Portugal); Silva, Paulo [PLASDAN - Maquinas para Plasticos, Marinha Grande (Portugal)

    2008-07-01

    The increasing demand for low temperature solar thermal collectors, especially for hot water production purposes in dwellings, swimming pools, hotels or industry, has lead to the possibility of high scale production, with leading manufacturers presenting yearly productions of hundreds of thousands of square meters. In such conditions, the use of polymeric materials in the manufacturing of solar collectors acquires particular interest, opening a full scope of opportunities for lower production costs, by means of cheaper materials or simpler manufacturing operations. Yet, the use of low cost materials limits the maximum operating temperatures estimated for the collectors (stagnation) to values around 120 C, easily attainable by any simple glazed solar collector. Higher performances, leading to higher stagnation temperatures as those observed for regular metal-based solar thermal collectors, would require high temperature polymers, at a much higher cost. The present paper addresses the manufacturing of a high performance solar thermal collector based in polymeric materials and includes a base thermal study, highlighting the different possibilities to be followed in the production of a polymeric collector, as well as a description of different temperature control strategies. (orig.)

  8. Comparison of rechargeable versus battery-operated insulin pumps: temperature fluctuations

    Directory of Open Access Journals (Sweden)

    Vereshchetin P

    2016-10-01

    Full Text Available Paul Vereshchetin, Thomas W McCann Jr, Navdeep Ojha, Ramakrishna Venugopalan, Brian L Levy Johnson & Johnson Diabetes Care Companies, Chesterbrook, PA, USA Abstract: The role of continuous subcutaneous insulin infusion (insulin pumps has become increasingly important in diabetes management, and many different types of these systems are currently available. This exploratory study focused on the reported heating issues that lithium-ion battery-powered pumps may have during charging compared with battery-operated pumps. It was found that pump temperature increased by 6.4°C during a long charging cycle of a lithium-ion battery-operated pump under ambient temperatures. In an environmental-chamber kept at 35°C, the pump temperature increased by 4.4°C, which indicates that the pump temperature was above that of the recommended safety limit for insulin storage of 37°C. When designing new pumps, and when using currently available rechargeable pumps in warmer climates, the implications of these temperature increases should be taken into consideration. Future studies should also further examine insulin quality after charging. Keywords: insulin pumps, diabetes mellitus, safety, heating

  9. Effect of lubricant jet location on spiral bevel gear operating temperatures

    Science.gov (United States)

    Handschuh, Robert F.

    1992-04-01

    An experimental study was conducted to determine the effect of lubricant jet location on spiral bevel gear bulk temperatures. Transient surface temperatures were also measured. Tests were conducted on aircraft quality spiral bevel gears in a closed loop test facility. Thermocoupled pinions and an infrared microscope were used to collect the pertinent data. A single fan jet lubricated the test gears. Lubricant flow rate (lubricant jet pressure) and applied torque were also varied. The results showed that jet placement had a significant effect on the gear bulk temperatures.

  10. High-temperature operation of broadband bidirectional terahertz quantum-cascade lasers

    Science.gov (United States)

    Khanal, Sudeep; Gao, Liang; Zhao, Le; Reno, John L.; Kumar, Sushil

    2016-09-01

    Terahertz quantum cascade lasers (QCLs) with a broadband gain medium could play an important role for sensing and spectroscopy since then distributed-feedback schemes could be utilized to produce laser arrays on a single semiconductor chip with wide spectral coverage. QCLs can be designed to emit at two different frequencies when biased with opposing electrical polarities. Here, terahertz QCLs with bidirectional operation are developed to achieve broadband lasing from the same semiconductor chip. A three-well design scheme with shallow-well GaAs/Al0.10Ga0.90As superlattices is developed to achieve high-temperature operation for bidirectional QCLs. It is shown that shallow-well heterostructures lead to optimal quantum-transport in the superlattice for bidirectional operation compared to the prevalent GaAs/Al0.15Ga0.85As material system. Broadband lasing in the frequency range of 3.1-3.7 THz is demonstrated for one QCL design, which achieves maximum operating temperatures of 147 K and 128 K respectively in opposing polarities. Dual-color lasing with large frequency separation is demonstrated for a second QCL, that emits at ~3.7 THz and operates up to 121 K in one polarity, and at ~2.7 THz up to 105 K in the opposing polarity. These are the highest operating temperatures achieved for broadband terahertz QCLs at the respective emission frequencies, and could lead to commercial development of broadband terahertz laser arrays.

  11. Operational and theoretical temperature considerations in a Penning surface plasma source

    Energy Technology Data Exchange (ETDEWEB)

    Faircloth, D. C., E-mail: dan.faircloth@stfc.ac.uk; Lawrie, S. R. [ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, OX11 0QX (United Kingdom); Pereira Da Costa, H. [CERN, Geneva (Switzerland); Dudnikov, V. [Muons Inc. United States of America (United States)

    2015-04-08

    A fully detailed 3D thermal model of the ISIS Penning surface plasma source is developed in ANSYS. The proportion of discharge power applied to the anode and cathode is varied until the simulation matches the operational temperature observations. The range of possible thermal contact resistances are modelled, which gives an estimation that between 67% and 85% of the discharge power goes to the cathode. Transient models show the electrode surface temperature rise during the discharge pulse for a range of duty cycles. The implications of these measurements are discussed and a mechanism for governing cesium coverage proposed. The requirements for the design of a high current long pulse source are stated.

  12. Modeling Temperature Development of Li-Ion Battery Packs in Hybrid Refuse Truck Operating at Different Ambient Conditions

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2014-01-01

    This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures.......This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures....

  13. Modeling Temperature Development of Li-Ion Battery Packs in Hybrid Refuse Truck Operating at Different Ambient Conditions

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2014-01-01

    This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures.......This paper presents a dynamic model for simulating the heat dissipation and the impact of Phase Change Materials (PCMs) on the peak temperature in Lithium-ion batteries during discharging operation of a hybrid truck under different ambient temperatures....

  14. Room-temperature operation of mid-infrared surface-plasmon quantum cascade lasers

    Science.gov (United States)

    Bahriz, M.; Moreau, V.; Palomo, J.; Krysa, A. B.; Austin, D.; Cockburn, J. W.; Roberts, J. S.; Wilson, L. R.; Julien, F.; Colombelli, R.

    2007-04-01

    We report the pulsed, room-temperature operation of an InGaAs/AllnAs quantum cascade laser at an operating wavelength of ≈ 7.5 μm in which the optical mode is a surface-plasmon polariton excitation. The use of a silver-based electrical contact with reduced optical losses at the laser emission wavelength allows for a reduction of the laser threshold current by a factor of two relative to samples with a gold-based contact layer.

  15. High Temperature Operation of 5.5μm Strain-Compensated Quantum Cascaded Lasers

    Institute of Scientific and Technical Information of China (English)

    LU Xiu-Zhen; LIU Feng-Qi; LIU Jun-Qi; JIN Peng; WANG Zhan-Guo

    2005-01-01

    @@ We develop 5.5-μm Inx Ga1-xAs/InyAl1-yAs strain-compensated quantum cascade lasers with InP and InGaAs cladding layers by using solid-source molecular-beam epitaxy. Pulse operation has been achieved up to 323K (50℃) for uncoated 20-μm-wide and 2-mm-long devices. These devices display an output power of 36mW with a duty cycle of 1% at room temperature. In continuous wave operation a record peak optical power of 10mW per facet has been measured at 83 K.

  16. A simple microfluidic Coriolis effect flowmeter for operation at high pressure and high temperature

    Science.gov (United States)

    Harrison, Christopher; Jundt, Jacques

    2016-08-01

    We describe a microfluidic Coriolis effect flowmeter that is simple to assemble, operates at elevated temperature and pressure, and can be operated with a lock-in amplifier. The sensor has a flow rate sensitivity greater than 2° of phase shift per 1 g/min of mass flow and is benchmarked with flow rates ranging from 0.05 to 2.0 g/min. The internal volume is 15 μl and uses off-the-shelf optical components to measure the tube motion. We demonstrate that fluid density can be calculated from the frequency of the resonating element with proper calibration.

  17. Determination of ice content in hardened concrete by low-temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn; Geiker, Mette Rica

    2014-01-01

    Low-temperature calorimetry has been used to determine the ice content in concrete at different temperatures when exposed to low-temperature environments. However, the analysis of the ice content from the measured data of heat flow is not straightforward. In this study, two important factors...

  18. Fast, Computer Supported Experimental Determination of Absolute Zero Temperature at School

    Science.gov (United States)

    Bogacz, Bogdan F.; Pedziwiatr, Antoni T.

    2014-01-01

    A simple and fast experimental method of determining absolute zero temperature is presented. Air gas thermometer coupled with pressure sensor and data acquisition system COACH is applied in a wide range of temperature. By constructing a pressure vs temperature plot for air under constant volume it is possible to obtain--by extrapolation to zero…

  19. High-density magnetoresistive random access memory operating at ultralow voltage at room temperature.

    Science.gov (United States)

    Hu, Jia-Mian; Li, Zheng; Chen, Long-Qing; Nan, Ce-Wen

    2011-11-22

    The main bottlenecks limiting the practical applications of current magnetoresistive random access memory (MRAM) technology are its low storage density and high writing energy consumption. Although a number of proposals have been reported for voltage-controlled memory device in recent years, none of them simultaneously satisfy the important device attributes: high storage capacity, low power consumption and room temperature operation. Here we present, using phase-field simulations, a simple and new pathway towards high-performance MRAMs that display significant improvements over existing MRAM technologies or proposed concepts. The proposed nanoscale MRAM device simultaneously exhibits ultrahigh storage capacity of up to 88 Gb inch(-2), ultralow power dissipation as low as 0.16 fJ per bit and room temperature high-speed operation below 10 ns.

  20. The Integrity of ACSR Full Tension Single-Stage Splice Connector at Higher Operation Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Lara-Curzio, Edgar [ORNL; King Jr, Thomas J [ORNL

    2008-10-01

    Due to increases in power demand and limited investment in new infrastructure, existing overhead power transmission lines often need to operate at temperatures higher than those used for the original design criteria. This has led to the accelerated aging and degradation of splice connectors. It is manifested by the formation of hot-spots that have been revealed by infrared imaging during inspection. The implications of connector aging is two-fold: (1) significant increases in resistivity of the splice connector (i.e., less efficient transmission of electricity) and (2) significant reductions in the connector clamping strength, which could ultimately result in separation of the power transmission line at the joint. Therefore, the splice connector appears to be the weakest link in electric power transmission lines. This report presents a protocol for integrating analytical and experimental approaches to evaluate the integrity of full tension single-stage splice connector assemblies and the associated effective lifetime at high operating temperature.

  1. High-Performing, Low-Temperature-Operating, Long-Lifetime Aerospace Lubricants

    Science.gov (United States)

    Joshi, Prakash

    2015-01-01

    Long-duration space exploration will require spacecraft systems that can operate effectively over several years with minimal or no maintenance. Aerospace lubricants are key components of spacecraft systems. Physical Sciences Inc., has synthesized and characterized novel ionic liquids for use in aerospace lubricants that contribute to decreased viscosity, friction, and wear in aerospace systems. The resulting formulations offer low vapor pressure and outgassing properties and thermal stability up to 250 C. They are effective for use at temperatures as low as -70 C and provide long-term operational stability in aerospace systems. In Phase II, the company scaled several new ionic liquids and evaluated a novel formulation in a NASA testbed. The resulting lubricant compounds will offer lower volatility, decreased corrosion, and better tribological characteristics than standard liquid lubricants, particularly at lower temperatures.

  2. Improved cycling behavior of ZEBRA battery operated at intermediate temperature of 175°C

    Energy Technology Data Exchange (ETDEWEB)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.

    2014-03-01

    Operation of sodium-nickel chloride battery at temperatures lower than 200°C reduces cell degradation and improves the cyclability. One of the main technical issues in terms of operating this battery at intermediate temperatures such as 175°C is the poor wettability of molten sodium on β”-alumina solid electrolyte (BASE) causing reduced active area and limited charging . In order to overcome the problem related to poor wettability of Na melt on BASE at 175°C, Pt grid was applied on the anode side of BASE using a screen printing technique. Deeper charging and improved cycling behavior was observed on the cells with metalized BASEs due to extended active area.

  3. INFLUENCE OF FUEL TEMPERATURE ON DIESEL ENGINE PERFORMANCE OPERATING WITH BIODIESEL BLEND

    Directory of Open Access Journals (Sweden)

    Rafidah Rahim

    2012-06-01

    Full Text Available This paper presents the study of the effect of temperature on diesel engine performance using a 5% biodiesel blend. A one-dimensional numerical analysis is used to simulate the four-cylinder diesel engine. The diesel engine simulation is used to study the characteristics of engine performance when the engine is operating with a fuel blend as an alternative fuel. The simulations are conducted at full load conditions where the temperature varies from 300 to 500 K. The results show that the maximum brake power and brake torque reduction was 1.39% and 1.13%, respectively for an engine operating with a fuel blend. It is shown that the insignificant different due to the small gap between energy content values. A decrease in the lower heating value caused an increase in the brake specific fuel consumption and thus, a reduction in the brake thermal efficiency of the engine performance at full load.

  4. Moderate-temperature operable SO2 gas sensor based on Zr4+ ion conducting solid electrolyte

    Directory of Open Access Journals (Sweden)

    Y. Uneme

    2012-12-01

    Full Text Available A solid electrolyte type sulfur dioxide (SO2 gas sensor that can operate at moderate temperatures was fabricated using Zr4+ ion conducting Zr39/40TaP2.9W0.1O12 solid electrolyte with 0.7La2O2SO4 − 0.3(0.8Li2SO4 + 0.2K2SO4 having a large surface area and Zr metal as the auxiliary sensing electrode and reference electrode, respectively. Since the present sensor showed a quantitative, reproducible and rapid response which obeys the theoretical Nernst relationship even at 400 °C, it is a potential on site SO2 gas sensing tool operable at moderate temperatures around 400 °C.

  5. Continuous-wave operation of a room-temperature Tm: YAP-pumped Ho: YAG laser

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    We report a continuous-wave (CW) 2.1-μm Ho:YAG laser operating at room temperature pumped by a diode-pumped 1.94-?m Tm:YAP laser.The maximum output power of 1.5 W is obtained from Ho:YAG laser,corresponding to Tm-to-Ho slope efficiency of 17.9% and diode-to-He conversion efficiency of 5.6%.

  6. Methodology for determining of the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants

    Energy Technology Data Exchange (ETDEWEB)

    Saunin, Yuri V.; Dobrotvorski, Alexander N.; Semenikhin, Alexander V. [JSC ' Atomtechenergo' , Filial ' Novovoronezhatomtechenergo' , Novovorenezh (Russian Federation); Ryasny, Sergei I. [JSC ' Atomtechenergo' , Mytishi (Russian Federation)

    2016-09-15

    At WWER-1000 NPPs, as well as at PWR NPPs, there is a problem of determining the correct weighted mean coolant temperature in the primary circuit hot legs based on the measuring channels information. The problem is caused by the coolant temperature stratification. The technical documentation for engineering support and maintenance of I and C systems does not provide any regulatory guidelines to consider this effect. Therefore, it is very important to represent a new methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of the WWER-1000 reactor plants. The given paper presents the basic preconditions and approaches applied during the methodology development. They were worked out on the basis of the executed numerical and experimental research taking into account the analysis of the extensive material obtained by the authors from full-scale tests during the commissioning of WWER-1000 power units, as well as operational data obtained from several power units with different fuel loadings.

  7. 16 CFR 305.5 - Determinations of estimated annual energy consumption, estimated annual operating cost, and...

    Science.gov (United States)

    2010-01-01

    ... consumption, estimated annual operating cost, and energy efficiency rating, and of water use rate. 305.5... RULE CONCERNING DISCLOSURES REGARDING ENERGY CONSUMPTION AND WATER USE OF CERTAIN HOME APPLIANCES AND... § 305.5 Determinations of estimated annual energy consumption, estimated annual operating cost, and...

  8. Study of fuel inlet temperature variations on palm biodiesel operating with a diesel engine

    Directory of Open Access Journals (Sweden)

    Mat Yasin Mohd Hafizil

    2017-01-01

    Full Text Available Biofuel includes biodiesel is introduced to overcome the air pollution problems. Biodiesel is the sustainable and alternative fuel that derived from edible and non-edible oil produced from bio-originated species, plants, and animals. This paper presents the simulation analysis on the effect of fuel temperature variations on diesel engine performance and emission using palm-biodiesel. A one-dimensional numerical analysis, Diesel RK software is used to simulate a single cylinder, four-stroke diesel engine on the performance and emission when operated at a full load condition using fuel temperature variations ranging 300 K to 333 K. Results showed that simulated results for brake power and brake torque were 0.7% each when compared to the highest and lowest fuel temperature ranging from 333 K to 300 K. Moreover, higher fuel temperature for palm biodiesel tends to produce lower exhaust gas temperature and brake specific fuel consumption at a constant engine speed of 2400 rpm. It can be concluded that from the study, fuel temperature variations of biodiesel could produce a significant effect regarding engine performance and emission that influence the driving economy of the engine.

  9. Effect of operating temperature on the HWB model for solar-collector design

    Science.gov (United States)

    Huang, H.; Howell, J. R.

    1983-02-01

    The Hottel-Whillier-Bliss (HWB) Model for the thermal efficiency of a flat plate solar collector plots as a straight line in an esa/sub c/ approx. (T/sub f,in/ - T/sub a/)/g/sub s/ coordinate system under the following assumptions: (1) the effect of the thermal capacity in the collector is negligible; (2) F/sub R/, U/sub L/ are constant in the range of operating temperature. These assumptions simplify the model and make it convenient to use. Because of the intermittance of insulation and the variation of ambient temperature and wind speed, the thermal capacity of the collector may affect the transient efficiency of the collector. In addition, the values of F/sub R/ and U/sub L/ are actually not constant and cause deviation of the efficiency curve from a straight line. The concern is with the deviation of the confidence level for a specific operating range. The effect of operating temperature of the values of F/sub R/ and U/sub L/ is discussed.

  10. Perturbation determinants in Banach spaces - with an application to eigenvalue estimates for perturbed operators

    OpenAIRE

    Hansmann, Marcel

    2015-01-01

    In the first part of this paper we provide a self-contained introduction to (regularized) perturbation determinants for operators in Banach spaces. In the second part, we use these determinants to derive new bounds on the discrete eigenvalues of compactly perturbed operators, broadly extending some recent results by Demuth et al. In addition, we also establish new bounds on the discrete eigenvalues of generators of $C_0$-semigroups.

  11. Fast determination of operational stability of the soluble acetylacetone-cleaving enzyme Dke1 in an enzyme membrane reactor.

    Science.gov (United States)

    Hofer, Hannes; Steiner, Walter

    2005-11-01

    The main aim of this study was the determination of the operational stability of soluble Dke1 (EC 1.13.11.50) in an enzyme membrane reactor. In order to calculate the half-life of soluble Dke1, the K (M) of oxygen must be known. The determination of this constant was done using progress curve analysis (K (M) = 260 micromol l(-1)). In a next step, the reactor system was studied by building a mathematical model for calculation of the reactor system, using Berkeley Madonna ver. 8.0.1 software. After that, the determination of the half-life of Dke1 under operational conditions at different temperatures (5, 10, 15, 25, 30, 35 degrees C) was performed. The quantitative criterion for stability was the value of the first-order rate constant of monomolecular inactivation. The experiments showed that soluble Dke1 is poorly stable. The half-life ranged from 308 min at 5 degrees C to 9 min at 35 degrees C. This method for determining the half-life is quite applicable for enzymes which are poorly stable. In addition, both the storage stability and the operational stability can be determined.

  12. Green monolithic II-VI vertical-cavity surface-emitting laser operating at room temperature

    Science.gov (United States)

    Kruse, C.; Ulrich, S. M.; Alexe, G.; Roventa, E.; Kröger, R.; Brendemühl, B.; Michler, P.; Gutowski, J.; Hommel, D.

    2004-02-01

    The realization of a monolithic all II-VI-based vertical cavity surface emitting laser (VCSEL) for the green spectral region is reported. Optically pumped lasing operation was achieved up to room temperature using a planar VCSEL structure. Taking advantage of distributed Bragg-reflectors based on MgS/Zn(Cd)Se superlattices as the low-refractive index material and ZnS0.06Se0.94 layers as the high-index material with a refractive index contrast of n = 0.6, a quality factor exceeding Q = 2000 is reached by using only 18 Bragg periods for the bottom DBR and 15 Bragg periods for the top DBR. The threshold power density is 0.32 MW/cm2 at a temperature of 10 K (emission wavelength 498.5 nm) and 1.9 MW/cm2 at room temperature (emission wavelength 502.3 nm).

  13. Numerical study of high-power semiconductor lasers for operation at sub-zero temperatures

    Science.gov (United States)

    Hasler, K. H.; Frevert, C.; Crump, P.; Erbert, G.; Wenzel, H.

    2017-04-01

    We present results on the impact of the Al-content in the waveguide structure on the electro-optical characteristics of 9xx nm, GaAs-based high-power lasers operated at room (300 K) and at sub-zero (200 K) heat sink temperatures. Experimentally a strong improvement of conversion efficiency and output power has been found if the lasers are cooled down. Numerical simulations using a software tool which solves the thermo-dynamic based drift-diffusion equations are able to reproduce the experimental findings. The reasons for the improved performance at lower temperatures are the enhancement of the modal gain and the reduced accumulation of electrons in the p-confinement layers resulting in a reduction of the leakage current. The latter allows the realization of lasers with a reduced Al content having a smaller series resistance and thus further enlarged conversion efficiency at sub-zero temperatures.

  14. HIGH COOLING WATER TEMPERATURE EFFECTS ON DESIGN AND OPERATIONAL SAFETY OF NPPS IN THE GULF REGION

    Directory of Open Access Journals (Sweden)

    BYUNG KOO KIM

    2013-12-01

    Full Text Available The Arabian Gulf region has one of the highest ocean temperatures, reaching above 35 degrees and ambient temperatures over 50 degrees in the summer. Two nuclear power plants (NPP are being introduced in the region for the first time, one at Bushehr (1,000 MWe PWR plant from Russia, and a much larger one at Barakah (4X1,400 MWe PWR from Korea. Both plants take seawater from the Gulf for condenser cooling, having to modify the secondary/tertiary side cooling systems design by increasing the heat transfer surface area from the country of origin. This paper analyses the secondary side of a typical PWR plant operating under the Rankine cycle with a simplified thermal-hydraulic model. Parametric study of ocean cooling temperatures is conducted to estimate thermal efficiency variations and its associated design changes for the secondary side. Operational safety is reviewed to deliver rated power output with acceptable safety margins in line with technical specifications, mainly in the auxiliary systems together with the cooling water temperature. Impact on the Gulf seawater as the ultimate heat sink is considered negligible, affecting only the adjacent water near the NPP site, when compared to the solar radiation on the sea surface.

  15. Electron density and temperature in NIO1 RF source operated in oxygen and argon

    Science.gov (United States)

    Barbisan, M.; Zaniol, B.; Cavenago, M.; Pasqualotto, R.; Serianni, G.; Zanini, M.

    2017-08-01

    The NIO1 experiment, built and operated at Consorzio RFX, hosts an RF negative ion source, from which it is possible to produce a beam of maximum 130 mA in H- ions, accelerated up to 60 kV. For the preliminary tests of the extraction system the source has been operated in oxygen, whose high electronegativity allows to reach useful levels of extracted beam current. The efficiency of negative ions extraction is strongly influenced by the electron density and temperature close to the Plasma Grid, i.e. the grid of the acceleration system which faces the source. To support the tests, these parameters have been measured by means of the Optical Emission Spectroscopy diagnostic. This technique has involved the use of an oxygen-argon mixture to produce the plasma in the source. The intensities of specific Ar I and Ar II lines have been measured along lines of sight close to the Plasma Grid, and have been interpreted with the ADAS package to get the desired information. This work will describe the diagnostic hardware, the analysis method and the measured values of electron density and temperature, as function of the main source parameters (RF power, pressure, bias voltage and magnetic filter field). The main results show that not only electron density but also electron temperature increase with RF power; both decrease with increasing magnetic filter field. Variations of source pressure and plasma grid bias voltage appear to affect only electron temperature and electron density, respectively.

  16. Determination of Temperature Rise and Temperature Differentials of CEMII/B-V Cement for 20MPa Mass Concrete using Adiabatic Temperature Rise Data

    Science.gov (United States)

    Chee Siang, GO

    2017-07-01

    Experimental test was carried out to determine the temperature rise characteristics of Portland-Fly-Ash Cement (CEM II/B-V, 42.5N) of Blaine fineness 418.6m2/kg and 444.6m2/kg respectively for 20MPa mass concrete under adiabatic condition. The estimation on adiabatic temperature rise by way of CIRIA C660 method (Construction Industry Research & Information Information) was adopted to verify and validate the hot-box test results by simulating the heat generation curve of the concrete under semi-adiabatic condition. Test result found that Portland fly-ash cement has exhibited decrease in the peak value of temperature rise and maximum temperature rise rate. The result showed that the temperature development and distribution profile, which is directly contributed from the heat of hydration of cement with time, is affected by the insulation, initial placing temperature, geometry and size of concrete mass. The mock up data showing the measured temperature differential is significantly lower than the technical specifications 20°C temperature differential requirement and the 27.7°C limiting temperature differential for granite aggregate concrete as stipulated in BS8110-2: 1985. The concrete strength test result revealed that the 28 days cubes compressive strength was above the stipulated 20MPa characteristic strength at 90 days. The test demonstrated that with proper concrete mix design, the use of Portland flyash cement, combination of chilled water and flake ice, and good insulation is effective in reducing peak temperature rise, temperature differential, and lower adiabatic temperature rise for mass concrete pours. As far as the determined adiabatic temperature rise result was concern, the established result could be inferred for in-situ thermal properties of 20MPa mass concrete application, as the result could be repeatable on account of similar type of constituent materials and concrete mix design adopted for permanent works at project site.

  17. Progress toward the Determination of Complete Vertex Operators for The IIB Matrix Model

    CERN Document Server

    Kitazawa, Y; Saito, O; Kitazawa, Yoshihisa; Mizoguchi, Shun'ya; Saito, Osamu

    2006-01-01

    We report on progress in determining the complete form of vertex operators for the IIB matrix model. The exact expressions are obtained for those emitting massless IIB supergravity fields up to sixth order in the light-cone superfield, in which the conjugate gravitino and conjugate two-form vertex operators are newly determined. We also provide a consistency check by computing the kinematical factor of a four-point graviton amplitude in a D-instanton background. We conjecture that the low-energy effective action of the IIB matrix model at large N is given by tree-level supergravity coupled to the vertex operators.

  18. Determining adjustment variables for rationalising a design for fleet operation in public passenger transport

    Directory of Open Access Journals (Sweden)

    Carlos Fabián Flórez Valero

    2010-04-01

    Full Text Available This investigation was aimed at establishing aspects leading to adjusting the operational design of public transport fleet operation to make it more profitable for private investors. Data obtained from more than a year’s operation by the Alianza Sat S.A. was used (this being a bus- company alliance grouping about 100 buses from some of Bogotá’s collective transport companies for carrying out the present investigation regarding fleet administration and operation. Simply implementing conventionally-designed routing plans is not enough for rationalising fleet operation, as most public collective transport is not directly operated by companies The Alianza Sat S.A. bus fleet was used for testing hypotheses demonstrating that current operational design for the company’s routes (in Bogotá’s current public transport market conditions leads to reducing the company’s income. The investigation revealed that public pas-senger transport bus fleet revenue can be increased if aspects different to those considered in standard route design methodology are controlled. The investigation has determined alternative rationalisation for operational collective public passenger transport company design regarding adjusting aspects such as the demand pattern, operating scheme, route variability, etc. This will provide an innovative and useful tool for rationalising the operational design of bus routes operating in cities having weak public transport control and excess bus supply.

  19. Classification of Traces and Associated Determinants on Odd-Class Operators in Odd Dimensions

    Directory of Open Access Journals (Sweden)

    Carolina Neira Jiménez

    2012-04-01

    Full Text Available To supplement the already known classification of traces on classical pseudodifferential operators, we present a classification of traces on the algebras of odd-class pseudodifferential operators of non-positive order acting on smooth functions on a closed odd-dimensional manifold. By means of the one to one correspondence between continuous traces on Lie algebras and determinants on the associated regular Lie groups, we give a classification of determinants on the group associated to the algebra of odd-class pseudodifferential operators with fixed non-positive order. At the end we discuss two possible ways to extend the definition of a determinant outside a neighborhood of the identity on the Lie group associated to the algebra of odd-class pseudodifferential operators of order zero.

  20. High temperature operation In1-xAlxSb infrared focal plane

    Science.gov (United States)

    Lyu, Yanqiu; Si, Junjie; Cao, Xiancun; Zhang, Liang; Peng, Zhenyu; Ding, Jiaxin; Yao, Guansheng; Zhang, Xiaolei; Reobrazhenskiy, Valeriy

    2016-05-01

    A high temperature operation mid-wavelength 128×128 infrared focal plane arrays (FPA) based on low Al component In1-xAlxSb was presented in this work. InAlSb materials were grown on InSb (100) substrates using MBE technology, which was confirmed by XRD and AFM analyses. We have designed and grown two structures with and without barrier. The pixel of the detector had a conventional PIN structure with a size of 50μmx50μm. The device fabrication process consisted of mesa etching, passivation, metallization and flip-chip hybridization with readout integrated circuit (ROIC), epoxy backfill, lap and polish. Diode resistance, imaging, NETD and operability results are presented for a progression of structures that reduce the diode leakage current as the temperature is raised above 80K. These include addition of a thin region of InAlSb to reduce p-contact leakage current, and construction of the whole device from InAlSb to reduce thermal generation in the active region of the detector. An increase in temperature to 110K, whilst maintaining full 80K performance, is achieved. The I-V curves were measured at different temperature. Quantum efficiency, pixel operability, non-uniformity, and the mean NETD values of the FPAs were measured at 110K. This gives the prospect of significant benefits for the cooling systems, including, for example, use of argon in Joule-Thomson coolers or an increase in the life and/or decrease in the cost, power consumption and cool-down time of Stirling engines by several tens of percent.

  1. Implementation of Fully Coupled Heat and Mass Transport Model to Determine Temperature and Moisture State at Elevated Temperatures

    DEFF Research Database (Denmark)

    Pecenko, R.; Hozjan, Tomaz; Svensson, Staffan

    2014-01-01

    The aim of this study is to present precise numerical formulation to determine temperature and moisture state of timber in the situation prior pyrolysis. The strong formulations needed for an accurate description of the physics are presented and discussed as well as their coupling terms. From the...

  2. Fuzzy self-tuning PID control of the operation temperatures in a two-staged membrane separation process

    Institute of Scientific and Technical Information of China (English)

    Lei Wang; Wencai Du; Hai Wang; Hong Wu

    2008-01-01

    A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As the conventional PID controller is difficult to make the operation temperatures steady, a fuzzy self-tuning PID control algorithm is proposed. The application shows that the algorithm is effective, the operation temperatures of both stages can be controlled steadily, and the operation flexibility and adaptability of the hydrogen recovery unit are enhanced with safety. This study lays a foundation to optimize the control of the membrane separation process and thus ensure the membrane performance.

  3. Reliability of temperature determination from curve-fitting in multi-wavelength pyrometery

    Energy Technology Data Exchange (ETDEWEB)

    Ni, P. A.; More, R. M.; Bieniosek, F. M.

    2013-08-04

    Abstract This paper examines the reliability of a widely used method for temperature determination by multi-wavelength pyrometry. In recent WDM experiments with ion-beam heated metal foils, we found that the statistical quality of the fit to the measured data is not necessarily a measure of the accuracy of the inferred temperature. We found a specific example where a second-best fit leads to a more realistic temperature value. The physics issue is the wavelength-dependent emissivity of the hot surface. We discuss improvements of the multi-frequency pyrometry technique, which will give a more reliable determination of the temperature from emission data.

  4. A New Operational Snow Retrieval Algorithm Applied to Historical AMSR-E Brightness Temperatures

    Directory of Open Access Journals (Sweden)

    Marco Tedesco

    2016-12-01

    Full Text Available Snow is a key element of the water and energy cycles and the knowledge of spatio-temporal distribution of snow depth and snow water equivalent (SWE is fundamental for hydrological and climatological applications. SWE and snow depth estimates can be obtained from spaceborne microwave brightness temperatures at global scale and high temporal resolution (daily. In this regard, the data recorded by the Advanced Microwave Scanning Radiometer—Earth Orbiting System (EOS (AMSR-E onboard the National Aeronautics and Space Administration’s (NASA AQUA spacecraft have been used to generate operational estimates of SWE and snow depth, complementing estimates generated with other microwave sensors flying on other platforms. In this study, we report the results concerning the development and assessment of a new operational algorithm applied to historical AMSR-E data. The new algorithm here proposed makes use of climatological data, electromagnetic modeling and artificial neural networks for estimating snow depth as well as a spatio-temporal dynamic density scheme to convert snow depth to SWE. The outputs of the new algorithm are compared with those of the current AMSR-E operational algorithm as well as in-situ measurements and other operational snow products, specifically the Canadian Meteorological Center (CMC and GlobSnow datasets. Our results show that the AMSR-E algorithm here proposed generally performs better than the operational one and addresses some major issues identified in the spatial distribution of snow depth fields associated with the evolution of effective grain size.

  5. Habitat Temperature and Precipitation of Arabidopsis thaliana Ecotypes Determine the Response of Foliar Vasculature, Photosynthesis, and Transpiration to Growth Temperature.

    Science.gov (United States)

    Adams, William W; Stewart, Jared J; Cohu, Christopher M; Muller, Onno; Demmig-Adams, Barbara

    2016-01-01

    Acclimatory adjustments of foliar vascular architecture, photosynthetic capacity, and transpiration rate in Arabidopsis thaliana ecotypes (Italian, Polish [Col-0], Swedish) were characterized in the context of habitat of origin. Temperatures of the habitat of origin decreased linearly with increasing habitat latitude, but habitat precipitation was greatest in Italy, lowest in Poland, and intermediate in Sweden. Plants of the three ecotypes raised under three different growth temperature regimes (low, moderate, and high) exhibited highest photosynthetic capacities, greatest leaf thickness, highest chlorophyll a/b ratio and levels of β-carotene, and greatest levels of wall ingrowths in phloem transfer cells, and, in the Col-0 and Swedish ecotypes, of phloem per minor vein in plants grown at the low temperature. In contrast, vein density and minor vein tracheary to sieve element ratio increased with increasing growth temperature - most strongly in Col-0 and least strongly in the Italian ecotype - and transpirational water loss correlated with vein density and number of tracheary elements per minor vein. Plotting of these vascular features as functions of climatic conditions in the habitat of origin suggested that temperatures during the evolutionary history of the ecotypes determined acclimatory responses of the foliar phloem and photosynthesis to temperature in this winter annual that upregulates photosynthesis in response to lower temperature, whereas the precipitation experienced during the evolutionary history of the ecotypes determined adjustment of foliar vein density, xylem, and transpiration to temperature. In particular, whereas photosynthetic capacity, leaf thickness, and foliar minor vein phloem features increased linearly with increasing latitude and decreasing temperature of the habitats of origin in response to experimental growth at low temperature, transpiration rate, foliar vein density, and minor vein tracheary element numbers and cross

  6. Habitat temperature and precipitation of Arabidopsis thaliana ecotypes determine the response of foliar vasculature, photosynthesis, and transpiration to growth temperature

    Directory of Open Access Journals (Sweden)

    William Walter Adams III

    2016-07-01

    Full Text Available Acclimatory adjustments of foliar vascular architecture, photosynthetic capacity, and transpiration rate in Arabidopsis thaliana ecotypes (Italian, Polish [Col-0], Swedish were characterized in the context of habitat of origin. Temperatures of the habitat of origin decreased linearly with increasing habitat latitude, but habitat precipitation was greatest in Italy, lowest in Poland, and intermediate in Sweden. Plants of the three ecotypes raised under three different growth temperature regimes (low, moderate, and high exhibited highest photosynthetic capacities, greatest leaf thickness, highest chlorophyll a/b ratio and levels of β-carotene, and greatest levels of wall ingrowths in phloem transfer cells, and, in the Col-0 and Swedish ecotypes, of phloem per minor vein in plants grown at the low temperature. In contrast, vein density and minor vein tracheary to sieve element ratio increased with increasing growth temperature – most strongly in Col-0 and least strongly in the Italian ecotype – and transpirational water loss correlated with vein density and number of tracheary elements per minor vein. Plotting of these vascular features as functions of climatic conditions in the habitat of origin suggested that temperatures during the evolutionary history of the ecotypes determined acclimatory responses of the foliar phloem and photosynthesis to temperature in this winter annual that upregulates photosynthesis in response to lower temperature, whereas the precipitation experienced during the evolutionary history of the ecotypes determined adjustment of foliar vein density, xylem, and transpiration to temperature. In particular, whereas photosynthetic capacity, leaf thickness, and foliar minor vein phloem features increased linearly with increasing latitude and decreasing temperature of the habitats of origin in response to experimental growth at low temperature, transpiration rate, foliar vein density, and minor vein tracheary element numbers

  7. Microcontroller based Stator Winding Resistance Determination of Induction Motor Drive on Temperature Variations

    Directory of Open Access Journals (Sweden)

    Siraj Ahmed T

    2014-05-01

    Full Text Available In this paper an experiment has been conducted to determine the online stator winding resistance of an induction motor, in industries as well as domestic purpose induction motors is largely utilized, as it has both applications of variable and constant torque operation nature. The major requirement of an electric drive system is its independent control of torque and speed; this is achieved in DC motor Drive but has more disadvantages. With the help of fast acting switching devices it is possible to independently control an induction motor. To control an induction motor drive various methods are available, direct torque control of induction motor is one of the best method of control compared to other, the only disadvantage is the torque ripple. Stator resistance is one of the parameter for the cause; hence its determination is essential. An experiment is conducted at various loads on an induction motor and then the temperature in the stator winding is noted at different instants using microcontroller, from the tabulated readings stator winding resistance is calculated and compared with the direct measurement by Volt-Ampere method. Further it is suggested that by implementing the actual online value of stator resistance of an induction motor dive torque ripple can be minimized.

  8. Stabilized composite membranes and membrane electrode assemblies for high temperature/low relative humidity polymer electrolyte fuel cell operation

    Science.gov (United States)

    Ramani, Vijay Krishna

    Polymer electrolyte membrane fuel cells (PEMFCs) have a variety of applications in the stationary power, mobile power and automotive power sectors. Existing membrane technology presently permits fuel cell operation at temperatures less than 100°C under fully saturated conditions. However, several advantages such as easier heat rejection rates and improved impurities tolerance by the anode electrocatalyst result by operating a PEMFC at elevated temperatures (above 100°C) and lower relative humidities. In an attempt to extend the operating range of the polymer electrolyte membrane, perfluorosulfonic acid (NafionRTM) based organic/inorganic (heteropolyacid) composite membranes were investigated in terms of thermal and electrochemical stability, additive stability and conductivity. Tungsten based heteropolyacids (HPAs) were found to be electrochemically stable as opposed to molybdenum based additives. The stability of the inorganic heteropolyacid additive in aqueous environments was enhanced by ion exchanging the protons of the HPAs with larger counter ions. An additional stabilization technique developed involved improving the interaction of HPA with NafionRTM by linking the particles to the sulfonic acid clusters via a sol-gel induced metal oxide linkage. The proton conductivity of the composite membranes was found to depend on the particle size of the HPA additive. A two order of magnitude change in additive particle size was attained by modification of the membrane preparation technique. This modification resulted in a nearly 50% increase in conductivity. The membranes prepared were characterized by thermal analysis, spectroscopy and microscopy. A technique was developed to incorporate existing MEA preparation and HPA stabilization techniques to the composite membranes with small HPA particles. All MEAs prepared were evaluated at high temperatures (120°C) and low relative humidities (35%) in an operating fuel cell, with membrane resistance and hence conductivity

  9. Ammonia and temperature determine potential clustering in the anaerobic digestion microbiome.

    Science.gov (United States)

    De Vrieze, Jo; Saunders, Aaron Marc; He, Ying; Fang, Jing; Nielsen, Per Halkjaer; Verstraete, Willy; Boon, Nico

    2015-05-15

    Anaerobic digestion is regarded as a key environmental technology in the present and future bio-based economy. The microbial community completing the anaerobic digestion process is considered complex, and several attempts already have been carried out to determine the key microbial populations. However, the key differences in the anaerobic digestion microbiomes, and the environmental/process parameters that drive these differences, remain poorly understood. In this research, we hypothesized that differences in operational parameters lead to a particular composition and organization of microbial communities in full-scale installations. A total of 38 samples were collected from 29 different full-scale anaerobic digestion installations, showing constant biogas production in function of time. Microbial community analysis was carried out by means of amplicon sequencing and real-time PCR. The bacterial community in all samples was dominated by representatives of the Firmicutes, Bacteroidetes and Proteobacteria, covering 86.1 ± 10.7% of the total bacterial community. Acetoclastic methanogenesis was dominated by Methanosaetaceae, yet, only the hydrogenotrophic Methanobacteriales correlated with biogas production, confirming their importance in high-rate anaerobic digestion systems. In-depth analysis of operational and environmental parameters and bacterial community structure indicated the presence of three potential clusters in anaerobic digestion. These clusters were determined by total ammonia concentration, free ammonia concentration and temperature, and characterized by an increased relative abundance of Bacteroidales, Clostridiales and Lactobacillales, respectively. None of the methanogenic populations, however, could be significantly attributed to any of the three clusters. Nonetheless, further experimental research will be required to validate the existence of these different clusters, and to which extent the presence of these clusters relates to stable or sub

  10. Influence of measurement errors on temperature-based death time determination.

    Science.gov (United States)

    Hubig, Michael; Muggenthaler, Holger; Mall, Gita

    2011-07-01

    Temperature-based methods represent essential tools in forensic death time determination. Empirical double exponential models have gained wide acceptance because they are highly flexible and simple to handle. The most established model commonly used in forensic practice was developed by Henssge. It contains three independent variables: the body mass, the environmental temperature, and the initial body core temperature. The present study investigates the influence of variations in the input data (environmental temperature, initial body core temperature, core temperature, time) on the standard deviation of the model-based estimates of the time since death. Two different approaches were used for calculating the standard deviation: the law of error propagation and the Monte Carlo method. Errors in environmental temperature measurements as well as deviations of the initial rectal temperature were identified as major sources of inaccuracies in model based death time estimation.

  11. Determination of magnetic characteristics of nanoparticles by low-temperature calorimetry methods

    Energy Technology Data Exchange (ETDEWEB)

    Ugulava, A.; Toklikishvili, Z. [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Chkhaidze, S., E-mail: simon.chkhaidze@tsu.ge [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Kekutia, Sh. [V. Chavchanidze Institute of Cybernetics, at the Technical State University, S. Euli str. 5, 0186 Tbilisi, Georgia (United States)

    2017-05-15

    At low temperatures, the heat capacity of a superparamagnetic “ideal gas” determined by magnetic degrees of freedom can greatly exceed the lattice heat capacity. It is shown that in the presence of an external magnetic field, the temperature dependence of the magnetic part of the heat capacity has two maxima. The relations between the temperature at which these maxima are achieved, the magnetic moment of the nanoparticles and the magnetic anisotropy constant have been obtained. Measuring the heat capacity maxima temperatures by low-temperature calorimetry methods and using the obtained relations, we can obtain the numerical values both of the magnetic moment of nanoparticles and the magnetic anisotropy constants.

  12. High Operating Temperature and Low Power Consumption Boron Nitride Nanosheets Based Broadband UV Photodetector

    Science.gov (United States)

    Rivera, Manuel; Velázquez, Rafael; Aldalbahi, Ali; Zhou, Andrew F.; Feng, Peter

    2017-03-01

    We extend our work on the use of digitally controlled pulsed laser plasma deposition (PLPD) technique to synthesize high quality, 2-dimensional single crystalline boron nitride nanosheets (BNNSs) at a low substrate temperature for applications in high-performance deep UV photodetectors. The obtained sample consists of a large amount of BNNSs partially overlapping one another with random orientations. Each sheet is composed of a few (from 2 to 10) stacked atomic layers exhibiting high transparency due to its highly ordered hBN crystallinity. Deep UV detectors based on the obtained BNNSs were designed, fabricated, and tested. The bias and temperature effects on the photocurrent strength and the signal-to-noise ratio have been carefully characterized and discussed. A significant shift in the cut off wavelength of the BNNSs based photodetectors was observed suggesting a band gap reduction as a result of the BNNSs’ collective structure. The newly designed photodetector presented exceptional properties: a high sensitivity to weak intensities of radiation in both UVC and UVB range while remaining visible-blind, and a high signal-to-noise ratio operation even at temperatures as high as 400 °C. In addition, the BNNSs based photodetector exhibited potential for self-powered operation.

  13. The effects of temperature on sex determination in the bloater Coregonus hoyi: a hypothesis test

    Science.gov (United States)

    Eck, Gary W.; Allen, Jeffrey D.

    1995-01-01

    The hypothesis that temperature was an epigamic factor in bloater (Coregonus hoyi) sex determination in Lake Michigan was tested by rearing bloater larvae in the laboratory at 6, 11, and 15 degrees C for the first 80 days after hatching. The percentages of females of fish exposed to the three treatment temperatures did not differ significantly from the expected, 50%. Therefore, the null hypothesis, that temperature did not influence bloater sex determination within the confines of this study, could not be rejected. Our study of bloater sex determination was an attempt to explain the extreme female predominance (> 95%) that occurred in the Lake Michigan bloater population during the 1960s.

  14. Modeling of thermoelectric module operation in inhomogeneous transient temperature field using finite element method

    Directory of Open Access Journals (Sweden)

    Nikolić Radovan H.

    2014-01-01

    Full Text Available This paper is the result of research and operation modeling of the new systems for cooling of cutting tools based on thermoelectric module. A copper inlay with thermoelectric module on the back side was added to a standard turning tool for metal processing. For modeling and simulating the operation of thermoelectric module, finite element method was used as a method for successful solving the problems of inhomogeneous transient temperature field on the cutting tip of lathe knives. Developed mathematical model is implemented in the software package PAK-T through which numerical results are obtained. Experimental research was done in different conditions of thermoelectric module operation. Cooling of the hot module side was done by a heat exchanger based on fluid using automatic temperature regulator. After the calculation is done, numerical results are in good agreement with experimental. It can be concluded that developed mathematical model can be used successfully for modeling of cooling of cutting tools. [Projekat Ministarstva nauke Republike Srbije, br. TR32036

  15. TRPV4 associates environmental temperature and sex determination in the American alligator.

    Science.gov (United States)

    Yatsu, Ryohei; Miyagawa, Shinichi; Kohno, Satomi; Saito, Shigeru; Lowers, Russell H; Ogino, Yukiko; Fukuta, Naomi; Katsu, Yoshinao; Ohta, Yasuhiko; Tominaga, Makoto; Guillette, Louis J; Iguchi, Taisen

    2015-12-18

    Temperature-dependent sex determination (TSD), commonly found among reptiles, is a sex determination mode in which the incubation temperature during a critical temperature sensitive period (TSP) determines sexual fate of the individual rather than the individual's genotypic background. In the American alligator (Alligator mississippiensis), eggs incubated during the TSP at 33 °C (male producing temperature: MPT) yields male offspring, whereas incubation temperatures below 30 °C (female producing temperature: FPT) lead to female offspring. However, many of the details of the underlying molecular mechanism remains elusive, and the molecular link between environmental temperature and sex determination pathway is yet to be elucidated. Here we show the alligator TRPV4 ortholog (AmTRPV4) to be activated at temperatures proximate to the TSD-related temperature in alligators, and using pharmacological exposure, we show that AmTRPV4 channel activity affects gene expression patterns associated with male differentiation. This is the first experimental demonstration of a link between a well-described thermo-sensory mechanism, TRPV4 channel, and its potential role in regulation of TSD in vertebrates, shedding unique new light on the elusive TSD molecular mechanism.

  16. Method for analyzing passive silicon carbide thermometry with a continuous dilatometer to determine irradiation temperature

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Anne A., E-mail: campbellaa@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Porter, Wallace D.; Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2016-03-01

    Highlights: • Annealing of SiC via continuous dilatometry to determine irradiation temperature. • Wrote a program to analyze dilatometry results to determine irradiation temperature. • Dilatometry results are consistent with results from a historical technique. • Computer program was written in an open-source language and is available for others. - Abstract: Silicon carbide is used as a passive post-irradiation temperature monitor because the irradiation defects will anneal out above the irradiation temperature. The irradiation temperature is determined by measuring a property change after isochronal annealing, i.e., lattice spacing, dimensions, electrical resistivity, thermal diffusivity, or bulk density. However, such methods are time-consuming since the steps involved must be performed in a serial manner. This work presents the use of thermal expansion from continuous dilatometry to calculate the SiC irradiation temperature, which is an automated process requiring minimal setup time. Analysis software was written that performs the calculations to obtain the irradiation temperature and removes possible user-introduced error while standardizing the analysis. This method has been compared to an electrical resistivity and isochronal annealing investigation, and the results revealed agreement of the calculated temperatures. These results show that dilatometry is a reliable and less time-intensive process for determining irradiation temperature from passive SiC thermometry.

  17. Determination of Anger Expression and Anger Management Styles and an Application on Operating Room Nurses

    Directory of Open Access Journals (Sweden)

    Hülya Aslan

    2016-12-01

    Full Text Available This research has been carried out in order to determine anger expression and anger management styles in operating room nurses. By applying an in-depth interview technique on operating room nurses working in a private hospital, a qualitative study has been performed in order to determine anger expression and anger management styles in operating room nurses. The interview consisted of ten questions such as demographic questions addressing the workers’ age, sex, education level and duration of employment in the organization they work, aiming to determine their anger expression and anger management styles. Since operating room environments contain various risk factors, and require active team work in a stressful dynamic setting under excessive workload, , it has been found that operating room nurses display their anger through loud speaking, fail to settle their anger positively, fail to control their anger in a behavioural pattern despite their cognitive awareness in anger management. Thus, it has been suggested that operating room nurses should be trained on anger management methods so that they can manage their anger in a stressful operating room environment.

  18. Determination of enthalpy-temperature curves of phase change materials with the temperature-history method: improvement to temperature dependent properties

    Science.gov (United States)

    Marín, José M.; Zalba, Belén; Cabeza, Luisa F.; Mehling, Harald

    2003-02-01

    The temperature-history method, proposed by Yinping et al, is a simple and economic way to determine the main thermophysical properties of materials used in thermal energy storage based on solid-liquid phase change. It is based on comparing the temperature history of a phase-change material sample and a sample of a well known material upon cooling down. In this paper we describe a further developed evaluation procedure to determine cp and h as temperature dependent values which was not the case in Yinping's method, based on the same experimental procedure. Given the suitability of these properties to calculate thermal energy storage using these materials, the method is proposed to present the results obtained in the form of enthalpy-temperature curves. A discussion about the errors produced by this method and an experimental improvement are proposed too.

  19. Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas%Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

    Institute of Scientific and Technical Information of China (English)

    刘秋艳; 李弘; 陈志鹏; 谢锦林; 刘万东

    2011-01-01

    Continuous emission spectrum measurement is applied for the inconvenient diagnos- tics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron tem- perature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method.

  20. Refractive index determination as a tool for temperature measurement and process control: a new approach

    Science.gov (United States)

    Schaller, Johannes K.; Wassenberg, S.; Fiedler, Detlev K.; Stojanoff, Christo G.

    1994-11-01

    Recently a new method for temperature measurement of droplets was presented. This method determines the index of refraction of a spherical scatterer with high accuracy and utilizes the dependence of the index of refraction on the temperature to finally determine the temperature. In this paper we show that the method is likewise applicable to cylindrical scatterers with a homogeneous refractive index distribution, like liquid jets. The method can be used to optically determine the temperature of a liquid jet, or to measure other properties of the liquid that influence the index of refraction of that liquid. One such property is the concentration of one liquid in another, like that of glycerol in an aqueous solution, which was studied experimentally for assessing some properties of the proposed method. An estimation of the sensitivity of the method was gained by detecting temperature changes of a cylindrical water jet.

  1. Optimal laser wavelength for efficient laser power converter operation over temperature

    Science.gov (United States)

    Höhn, O.; Walker, A. W.; Bett, A. W.; Helmers, H.

    2016-06-01

    A temperature dependent modeling study is conducted on a GaAs laser power converter to identify the optimal incident laser wavelength for optical power transmission. Furthermore, the respective temperature dependent maximal conversion efficiencies in the radiative limit as well as in a practically achievable limit are presented. The model is based on the transfer matrix method coupled to a two-diode model, and is calibrated to experimental data of a GaAs photovoltaic device over laser irradiance and temperature. Since the laser wavelength does not strongly influence the open circuit voltage of the laser power converter, the optimal laser wavelength is determined to be in the range where the external quantum efficiency is maximal, but weighted by the photon flux of the laser.

  2. Above room temperature continuous wave operation of a broad-area quantum-cascade laser

    Science.gov (United States)

    Semtsiv, M. P.; Masselink, W. T.

    2016-11-01

    We describe the design and implementation of a broad-area (w ≈ 30 μm) quantum-cascade laser operating in a continuous wave mode up to heat-sink temperatures beyond +100 °C. The room-temperature emission wavelength is 4.6 μm. The temperature gradient in the active region of such a wide laser stripe is essentially perpendicular to the epitaxial layers and the resulting steady-state active region temperature offset scales approximately with the square of the number of cascades. With only 10 cascades in the active region, the threshold electrical power density in the current quantum-cascade laser in the continuous-wave mode is as low as Vth × Ith = 3.8 V × 0.9 kA/cm2 = 3.4 kW/cm2 at room temperature for 2 mm-long two-side high-reflectivity coated laser stripe. A 4 mm-long one-side high-reflectivity coated laser stripe delivers in continuous-wave mode above 0.6 W at +20 °C and above 1.3 W at -27 °C (cooled with a single-stage Peltier element). A 2 mm-long two-side high-reflectivity coated laser stripe demonstrates continuous-wave lasing up to at least +102 °C (375 K). The thermal conductance, Gth, ranges between 235 W/K cm2 and 140 W/K cm2 for temperatures between -33 °C and +102 °C. This demonstration opens the route for continuous-wave power scaling of quantum-cascade lasers via broad-area laser ridges.

  3. Feasibility study of SiGHT: a novel ultra low background photosensor for low temperature operation

    CERN Document Server

    Wang, Yi; Fiorillo, Giuliana; Galbiati, Cristiano; Guan, Meng-Yun; Korga, George; Pantic, Emilija; Razeto, Alessandro; Renshaw, Andrew; Rossi, Biagio; Suvorov, Yury; Wang, Hanguo; Yang, Chang-Gen

    2016-01-01

    Rare event search experiments, such as those searching for dark matter and observations of neutrinoless double beta decay, require ultra low levels of radioactive background for unmistakable identification. In order to reduce the radioactive backgrounds of detectors used in these types of event searches, low background photosensors are required, as the physical size of these detectors become increasing larger, and hence the number of such photosensors used also increases rapidly. Considering that most dark matter and neutrinoless double beta decay experiments are turning towards using noble liquids as the target choice, liquid xenon and liquid argon for instance, photosensors that can work well at cryogenic temperatures are required, 165 K and 87 K for liquid xenon and liquid argon, respectively. The Silicon Geiger Hybrid Tube (SiGHT) is a novel photosensor designed specifically for use in ultra low background experiments operating at cryogenic temperatures. It is based on the proven photocathode plus silicon...

  4. The Effect Of Temperature On The Performance Of PV Array Operating Under Concentration

    Directory of Open Access Journals (Sweden)

    Eng. Sameh. M.El Sayed

    2015-08-01

    Full Text Available Abstract The sun is the worlds sole source of energy. In fact all of the energy being used on the earth today is driven from solar energy. Because of the increase in world energy demand and the threat of global warming there is a pressing need for the development of reliable cost-effective sources of renewable energy. Renewable energy sources include indirect solar energy such as hydro wind and direct solar energy conversion through thermal receivers or photovoltaic. This paper discusses the parameters that affects on the cell temperature under concentration. Comparison between fixed modules and solar cells operating under concentration to get the optimum solution. By increasing the concentration factor one minimizes the area of the cell .System uses special cell Fresnel lens and multilayer cells.This cell has large efficiency and bear high temperature. The economic studies are necessary to calculate the cost of 1kwh for each case.

  5. Room-temperature operation of a titanium supersaturated silicon-based infrared photodetector

    Science.gov (United States)

    García-Hemme, E.; García-Hernansanz, R.; Olea, J.; Pastor, D.; del Prado, A.; Mártil, I.; González-Díaz, G.

    2014-05-01

    We report room-temperature operation of 1 × 1 cm2 infrared photoconductive photodetectors based on silicon supersaturated with titanium. We have fabricated these Si-based infrared photodetectors devices by means of ion implantation followed by a pulsed laser melting process. A high sub-band gap responsivity of 34 mV W-1 has been obtained operating at the useful telecommunication applications wavelength of 1.55 μm (0.8 eV). The sub-band gap responsivity shows a cut-off frequency as high as 1.9 kHz. These Si-based devices exhibit a non-previous reported specific detectivity of 1.7 × 104 cm Hz1/2 W-1 at 660 Hz, under a 1.55 μm wavelength light. This work shows the potential of Ti supersaturated Si as a fully CMOS-compatible material for the infrared photodetection technology.

  6. [Evaluation of operation ergonomics at high-temperature in the cockpit].

    Science.gov (United States)

    Tian, Yinsheng; Li, Jing; Ding, Li; Wang, Qiong; Ren, Zhaosheng; Shi, Liyong; Xue, Lihao

    2011-08-01

    10 male subjects participated in the environmental simulation study to evaluate the operation ergonomics at high-temperature in the cockpit. Grip strength, perception, dexterity, reaction and intelligence were measured respectively during the tests at 40 degrees C and 45 degrees C, simulating the high-temperatures in a simulation cockpit chamber. Then the data obtained were compared to the combined index of heat stress (CIHS). The average values of each item of the subjects' performance at the two different temperatures are compared. The results indicated that CIHS exceeded the heat stress safety line after 45 min at 40 degrees C, grip strength decreased by 12%, and perception increased by 2.89 times. In contrast, at 45 degrees C, CIHS exceeded the safety line after 20 min, grip strength decreased by 3.2%, and perception increased by 4.36 times. However, Finger dexterity was less affected. Reaction ability was first accelerated, and then slowed down. The error rate in the intelligence test increased to a greater extent. At the high temperatures, the minimum perception was the most affected, followed by grip strength, reaction and finger dexterity were less affected, while the intelligence did not decline, but rise.

  7. Helium-filled proportional counter and its operation mechanism at low temperatures

    CERN Document Server

    Isozumi, Y; Kishimoto, S

    2002-01-01

    The operation mechanism of helium-filled proportional counter (HFPC) at about 4.2 K is explained. Unstable behavior of HFPC is caused by releasing secondary-electron from the cathode by four kinds of active particles such as He sub n sup + , non-resonance photon from excited helium atom, non-resonance photon from He sub 2 sup * (A sup 1 Su sup +) and He sub 2 sup m (a sup 3 Su sup +). On experiments of HFPC behavior at low temperature, the following facts were observed; 1) main charge formation process in the electron avalanche is direct ionization by electron without Hornbeck-Molnar process. Accordingly, the gas amplification factor becomes small at low temperature. 2) Stable helium cation is He sub 2 sup + at room temperature, but cluster at low temperature. Large after-pulse is observed in output signal depends on cluster ion. The probability of secondary-electron emission decreased. The gas gain increased with increasing anode voltage. 3) By decreasing reaction rate of atom and molecule collision at low t...

  8. Studying randomness and determinism in surface temperature anomaly indices using the recurrence plot method

    Science.gov (United States)

    Kiselev, B. V.

    2016-01-01

    Surface temperature anomalies are studied using the methods of recurrence plots and statistical R/S analysis, as well as the Higuchi method for determining fractal dimension. Anomalies of the surface temperature above continents and the temperature in the World Ocean regions and in the Northern and Southern hemispheres are considered independently. It has been indicated that anomalies are more stochastic and deterministic for land and ocean surfaces, respectively.

  9. Determination of needed parameters for measuring temperature fields in air by thermography

    Directory of Open Access Journals (Sweden)

    Pavelek Milan

    2012-04-01

    Full Text Available The aim of this article is the parameters determination of equipment for measuring temperature fields in air using an infrared camera. This method is based on the visualization of temperature fields in an auxiliary material, which is inserted into the non-isothermal air flow. The accuracy of air temperature measurement (or of surface temperature of supplies by this method depends especially on (except for parameters of infrared camera the determination of the static and the dynamic qualities of auxiliary material. The emissivity of support material is the static quality and the dynamic quality is time constant. Support materials with a high emissivity and a low time constant are suitable for the measurement. The high value of emissivity results in a higher measurement sensitivity and the radiation temperature independence. In this article the emissivity of examined kinds of auxiliary materials (papers and textiles is determined by temperature measuring of heated samples by a calibrated thermocouple and by thermography, with the emissivity setting on the camera to 1 and with the homogeneous radiation temperature. Time constants are determined by a step change of air temperature in the surrounding of auxiliary material. The time constant depends mainly on heat transfer by the convection from the air into the auxiliary material. That is why the effect of air temperature is examined in this article (or a temperature difference towards the environmental temperature and the flow velocity on the time constant with various types of auxiliary materials. The obtained results allow to define the conditions for using the method of measurement of temperature fields in air during various heating and air conditioning applications.

  10. Room Temperature Operation of a Radiofrequency Diamond Magnetometer near the Shot Noise Limit

    CERN Document Server

    Shin, Chang S; Butler, Mark C; Trease, David R; Seltzer, Scott J; Mustonen, J Peter; Kennedy, Daniel J; Acosta, Victor M; Budker, Dmitry; Pines, Alexander; Bajaj, Vikram S

    2012-01-01

    We operate a nitrogen vacancy (NV-) diamond magnetometer at ambient temperatures and study the dependence of its bandwidth on experimental parameters including optical and microwave excitation powers. We introduce an analytical theory that yields an explicit formula for the response of an ensemble of NV- spins to an oscillating magnetic field, such as in NMR applications. We measure a detection bandwidth of 1.6 MHz and a sensitivity of 4.6 nT/Hz^(1/2), unprecedented in a detector with this active volume and close to the photon shot noise limit of our experiment.

  11. Parameter-free determination of actual temperature at chemical freeze-out in nuclear interactions

    Science.gov (United States)

    Panagiotou, A. D.; Mavromanolakis, G.; Tzoulis, J.

    1995-07-01

    We propose a method to determine the actual temperature at chemical freeze-out in relativistic nucleus-nucleus collisions, using the experimental μq/T and μs/T values, obtained from strange particle ratios. We employ the Hadron Gas formalism, assuming only local thermal equilibration, to relate the quarkchemical potential and temperature. This relation constrains the allowed values of μq/T, μs/T and T, enabling the determination of the actual temperature. Comparison of the inverse slope parameter of the mT-distributions with the actual temperature determines the transverse flow velocity of the fireball matter. Knowledge of these quantities is essential in determining the EoS of nuclear matter and in evaluating interactions with regard to a possible phase transition to QGP.

  12. Electromagnetic power absorption and temperature changes due to brain machine interface operation.

    Science.gov (United States)

    Ibrahim, Tamer S; Abraham, Doney; Rennaker, Robert L

    2007-05-01

    To fully understand neural function, chronic neural recordings must be made simultaneously from 10s or 100s of neurons. To accomplish this goal, several groups are developing brain machine interfaces. For these devices to be viable for chronic human use, it is likely that they will need to be operated and powered externally via a radiofrequency (RF) source. However, RF exposure can result in tissue heating and is regulated by the FDA/FCC. This paper provides an initial estimate of the amount of tissue heating and specific absorption rate (SAR) associated with the operation of a brain-machine interface (BMI). The operation of a brain machine interface was evaluated in an 18-tissue anatomically detailed human head mesh using simulations of electromagnetics and bio-heat phenomena. The simulations were conducted with a single chip, as well as with eight chips, placed on the surface of the human brain and each powered at four frequencies (13.6 MHz, 1.0 GHz, 2.4 GHz, and 5.8 GHz). The simulated chips consist of a wire antenna on a silicon chip covered by a Teflon dura patch. SAR values were calculated using the finite-difference time-domain method and used to predict peak temperature changes caused by electromagnetic absorption in the head using two-dimensional bio-heat equation. Results due to SAR alone show increased heating at higher frequencies, with a peak temperature change at 5.8 GHz of approximately 0.018 degrees C in the single-chip configuration and 0.06 degrees C in the eight-chip configuration with 10 mW of power absorption (in the human head) per chip. In addition, temperature elevations due to power dissipation in the chip(s) were studied. Results show that for the neural tissue, maximum temperature rises of 3.34 degrees C in the single-chip configuration and 7.72 degrees C in the eight-chip configuration were observed for 10 mW dissipation in each chip. Finally, the maximum power dissipation allowable in each chip before a 1.0 degrees C temperature

  13. Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Sørensen, O. H.; Mygind, Jesper

    1978-01-01

    The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature Tc of the Sn films. The temperature dependence of the cosφ conductance is determined from the resonant response at the junction plasma frequency fp...... of the experiment....

  14. Segregating variation for temperature-dependent sex determination in a lizard

    OpenAIRE

    Rhen, T; Schroeder, A.; Sakata, J T; Huang, V.; Crews, D.

    2010-01-01

    Temperature-dependent sex determination (TSD) was first reported in 1966 in an African lizard. It has since been shown that TSD occurs in some fish, several lizards, tuataras, numerous turtles and all crocodilians. Extreme temperatures can also cause sex reversal in several amphibians and lizards with genotypic sex determination. Research in TSD species indicates that estrogen signaling is important for ovary development and that orthologs of mammalian genes have a function in gonad different...

  15. Determining magnetic phase transitions temperatures in working magnetocaloric coolers bodies and gas cryorefrigerators regenerators

    Science.gov (United States)

    Karagusov, V. I.; Mayankov, I. V.

    2017-08-01

    Due to magnetic phase transitions rare-earth materials possess unique properties near the Curie and Neel temperatures, such as the magneto-caloric effect, the abnormally high heat capacity, the magnetic susceptibility and permeability extremes. Using rare earth materials in gas cryogenic refrigerators regenerators increases the efficiency, reduces the power consumption and allows reaching helium temperatures. The magneto-caloric effect has also extreme values near the Curie and Neel temperatures. The paper presents theoretical and experimental methods allowing to determine magnetic phase transitions temperatures in a wide range of low temperature materials with a various rare-earth components content and expected thermophysical properties of a certain rare-earth materials composition at the temperatures based on starting pure metals characteristics. The results analysis has shown that magnetic phase transitions temperatures are a linear function of the components concentration. Moreover, heat capacity values and MCE also depend linearly on the starting components concentration, which simplifies calculations significantly.

  16. Non-invasive, transient determination of the core temperature of a heat-generating solid body

    Science.gov (United States)

    Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

    2016-11-01

    While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role.

  17. Non-invasive, transient determination of the core temperature of a heat-generating solid body.

    Science.gov (United States)

    Anthony, Dean; Sarkar, Daipayan; Jain, Ankur

    2016-11-02

    While temperature on the surface of a heat-generating solid body can be easily measured using a variety of methods, very few techniques exist for non-invasively measuring the temperature inside the solid body as a function of time. Measurement of internal temperature is very desirable since measurement of just the surface temperature gives no indication of temperature inside the body, and system performance and safety is governed primarily by the highest temperature, encountered usually at the core of the body. This paper presents a technique to non-invasively determine the internal temperature based on the theoretical relationship between the core temperature and surface temperature distribution on the outside of a heat-generating solid body as functions of time. Experiments using infrared thermography of the outside surface of a thermal test cell in a variety of heating and cooling conditions demonstrate good agreement of the predicted core temperature as a function of time with actual core temperature measurement using an embedded thermocouple. This paper demonstrates a capability to thermally probe inside solid bodies in a non-invasive fashion. This directly benefits the accurate performance prediction and control of a variety of engineering systems where the time-varying core temperature plays a key role.

  18. A high-temperature gas-and-steam turbine plant operating on combined fuel

    Science.gov (United States)

    Klimenko, A. V.; Milman, O. O.; Shifrin, B. A.

    2015-11-01

    A high-temperature gas-steam turbine plant (GSTP) for ultrasupercritical steam conditions is proposed based on an analysis of prospects for the development of power engineering around the world and in Russia up to 2040. The performance indicators of a GSTP using steam from a coal-fired boiler with a temperature of 560-620°C with its superheating to 1000-1500°C by firing natural gas with oxygen in a mixingtype steam superheater are analyzed. The thermal process circuit and design of a GSTP for a capacity of 25 MW with the high- and intermediate-pressure high-temperature parts with the total efficiency equal to 51.7% and the natural gas utilization efficiency equal to 64-68% are developed. The principles of designing and the design arrangement of a 300 MW GSTP are developed. The effect of economic parameters (the level and ratio of prices for solid fuel and gas, and capital investments) on the net cost of electric energy is determined. The net cost of electric energy produced by the GSTP is lower than that produced by modern combined-cycle power plants in a wide variation range of these parameters. The components of a high-temperature GSTP the development of which determines the main features of such installations are pointed out: a chamber for combusting natural gas and oxygen in a mixture with steam, a vacuum device for condensing steam with a high content of nondensables, and a control system. The possibility of using domestically available gas turbine technologies for developing the GSTP's intermediate-pressure high-temperature part is pointed out. In regard of its environmental characteristics, the GSTP is more advantageous as compared with modern condensing power plants: it allows a flow of concentrated carbon dioxide to be obtained at its outlet, which can be reclaimed; in addition, this plant requires half as much consumption of fresh water.

  19. High-temperature passive direct methanol fuel cells operating with concentrated fuels

    Science.gov (United States)

    Zhao, Xuxin; Yuan, Wenxiang; Wu, Qixing; Sun, Hongyuan; Luo, Zhongkuan; Fu, Huide

    2015-01-01

    Conventionally, passive direct methanol fuel cells (DMFC) are fed with diluted methanol solutions and can hardly be operated at elevated temperatures (>120 °C) because the ionic conductivity of Nafion-type proton exchange membranes depends strongly on water content. Such a system design would limit its energy density and power density in mobile applications. In this communication, a passive vapor feed DMFC capable of operating with concentrated fuels at high temperatures is reported. The passive DMFC proposed in this work consists of a fuel reservoir, a perforated silicone sheet, a vapor chamber, two current collectors and a membrane electrode assembly (MEA) based on a phosphoric acid doped polybenzimidazole (PBI) membrane. The experimental results reveal that the methanol crossover through a PBI membrane is substantially low when compared with the Nafion membranes and the PBI-based passive DMFC can yield a peak power density of 37.2 mW cm-2 and 22.1 mW cm-2 at 180 °C when 16 M methanol solutions and neat methanol are used respectively. In addition, the 132 h discharge test indicates that the performance of this new DMFC is quite stable and no obvious performance degradation is observed after activation, showing its promising applications in portable power sources.

  20. Demonstration and Comparison of Operation of Photomultiplier Tubes at Liquid Argon Temperature

    CERN Document Server

    Acciarri, R; Boffelli, F; Cambiaghi, M; Canci, N; Cavanna, F; Cocco, A G; Di Pompeo, F; Fiorillo, G; Galbiati, C; Grandi, L; Kryczynski, P; Meng, G; Montanari, C; Palamara, O; Pandola, L; Perfetto, F; Mortari, G B Piano; Pietropaolo, F; Raselli, G L; Rossella, M; Rubbia, C; Segreto, E; Szelc, A M; Triossi, A; Ventura, S; Vignoli, C; Zani, A

    2011-01-01

    Liquified noble gases are widely used as a target in direct Dark Matter searches. Signals from scintillation in the liquid, following energy deposition from the recoil nuclei scattered by Dark Matter particles (e.g. WIMPs), should be recorded down to very low energies by photosensors suitably designed to operate at cryogenic temperatures. Liquid Argon based detectors for Dark Matter searches currently implement photo multiplier tubes for signal read-out. In the last few years PMTs with photocathodes operating down to liquid Argon temperatures (87 K) have been specially developed with increasing Quantum Efficiency characteristics. The most recent of these, Hamamatsu Photonics Mod. R11065 with peak QE up to about 35%, has been extensively tested within the R&D program of the WArP Collaboration. During these testes the Hamamatsu PMTs showed superb performance and allowed obtaining a light yield around 7 phel/keVee in a Liquid Argon detector with a photocathodic coverage in the 12% range, sufficient for detec...

  1. Low temperature operated NiO-SnO2 heterostructured SO2 gas sensor

    Science.gov (United States)

    Tyagi, Punit; Sharma, Anjali; Tomar, Monika; Gupta, Vinay

    2016-04-01

    Sulfur dioxide (SO2) is among the most toxic gas released by the industries which is extremely dangerous for human health. In the present communication, an attempt has been made for the detection of SO2 gas (500 ppm) with the help of SnO2 thin film based gas sensor. A low sensing response of 1.3 is obtained for sputtered SnO2 thin films based sensors at a high operating temperature of 220 °C. To improve the sensing response, different heterostructured sensors are developed by incorporating other metal oxide thin films (PdO, MgO, NiO, V2O5) over SnO2 thin film surface. Sensing response studies of different sensors towards SO2 gas (500 ppm) are presented in the present report. Among all the prepared sensors NiO-SnO2 hetero-structure sensor is showing highest sensing response (˜8) at a comparatively lower operating temperature (140 °C). Possible sensing mechanism for NiO-SnO2 heterostructured sensor has also been discussed in the present report.

  2. Near surface spatially averaged air temperature and wind speed determined by acoustic travel time tomography

    Directory of Open Access Journals (Sweden)

    Armin Raabe

    2001-03-01

    Full Text Available Acoustic travel time tomography is presented as a possibility for remote monitoring of near surface airtemperature and wind fields. This technique provides line-averaged effective sound speeds changing with temporally and spatially variable air temperature and wind vector. The effective sound speed is derived from the travel times of sound signals which propagate at defined paths between different acoustic sources and receivers. Starting with the travel time data a tomographic algorithm (Simultaneous Iterative Reconstruction Technique, SIRT is used to calculate area-averaged air temperature and wind speed. The accuracy of the experimental method and the tomographic inversion algorithm is exemplarily demonstrated for one day without remarkable differences in the horizontal temperature field, determined by independent in situ measurements at different points within the measuring field. The differences between the conventionally determined air temperature (point measurement and the air temperature determined by tomography (area-averaged measurement representative for the area of the measuring field 200m x 260m were below 0.5 K for an average of 10 minutes. The differences obtained between the wind speed measured at a meteorological mast and calculated from acoustic measurements are not higher than 0.5 ms-1 for the same averaging time. The tomographically determined area-averaged distribution of air temperature (resolution 50 m x 50 m can be used to estimate the horizontal gradient of air temperature as a pre-condition to detect horizontal turbulent fluxes of sensible heat.

  3. Unified approach for determining the enthalpic fictive temperature of glasses with arbitrary thermal history

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Potuzak, M.; Mauro, J. C.

    2011-01-01

    We propose a unified routine to determine the enthalpic fictive temperature of a glass with arbitrary thermal history under isobaric conditions. The technique is validated both experimentally and numerically using a novel approach for modeling of glass relaxation behavior. The technique is applic......We propose a unified routine to determine the enthalpic fictive temperature of a glass with arbitrary thermal history under isobaric conditions. The technique is validated both experimentally and numerically using a novel approach for modeling of glass relaxation behavior. The technique...... is applicable to glasses of any thermal history, as proved through a series of numerical simulations where the enthalpic fictive temperature is precisely known within the model. Also, we demonstrate that the enthalpic fictive temperature of a glass can be determined at any calorimetric scan rate in excellent...

  4. Modelling and operation of sub-miniature constant temperature hot-wire anemometry

    Science.gov (United States)

    Samie, M.; Watmuff, J. H.; Van Buren, T.; Hutchins, N.; Marusic, I.; Hultmark, M.; Smits, A. J.

    2016-12-01

    High-Reynolds number flows are very common in technological applications and in nature, and hot-wire anemometry is the preferred method for measuring the time-series of fluctuating velocity in such flows. However, measurement of very high-Reynolds number flows requires hot-wires with higher temporal and spatial resolution than is available with conventional probes. Much effort has therefore been devoted to decreasing the size of the hot-wire probes and this has led to associated challenges with operation. It is this latter operation problem which is the focus of this paper. To this end, an existing theoretical model of constant-temperature hot-wire anemometers (Perry 1982 Hot-Wire Anemometry (New York: Oxford University Press), Watmuff 1995 Exp. Therm. Fluid Sci. 11 117-34) is applied, and its accuracy is tested for the first time by comparison to measurements using an in-house constant temperature anemometer (CTA) for both conventional 5~μ m-diameter wires and sub-miniature hot-wires. With the aid of this model, we propose modifications to the CTA design and demonstrate successful operation of the CTA with the Princeton nano-scale thermal anemometry probe (NSTAP) (Bailey et al 2010 J. Fluid Mech. 663 160-79). It is also shown that the transfer function obtained from the model can be utilized to estimate the true frequency response and cut-off frequency of a hot-wire-CTA system to the velocity fluctuations, which is essential in accurate measurements of energy spectrum and higher order statistics of turbulent flows.

  5. High temperature operation of a composite membrane-based solid polymer electrolyte water electrolyser

    Energy Technology Data Exchange (ETDEWEB)

    Antonucci, V.; Di Blasi, A.; Baglio, V.; Arico, A.S. [CNR-ITAE, Via Salita S. Lucia sopra Contesse 5, 98126 Messina (Italy); Ornelas, R.; Matteucci, F. [Tozzi Apparecchiature Elettriche SpA, Via Zuccherificio, 10-48010 Mezzano (RA) (Italy); Ledesma-Garcia, J.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Parque Tecnologico Queretaro, Sanfandila, Pedro Escobedo, C.P. 76703 Queretaro (Mexico)

    2008-10-15

    The high temperature behaviour of a solid polymer electrolyte (SPE) water electrolyser based on a composite Nafion-SiO{sub 2} membrane was investigated and compared to that of a commercial Nafion membrane. The SPE water electrolyser performance was studied from 80 to 120{sup o}C with an operating pressure varying between 1 and 3 bar abs. IrO{sub 2} and Pt were used as oxygen and hydrogen evolution catalysts, respectively. The assemblies were manufactured by using a catalyst-coated membrane (CCM) technique. The performance was significantly better for the composite Nafion-SiO{sub 2} membrane than commercial Nafion 115. Furthermore, the composite membrane allowed suitable water electrolysis at high temperature under atmospheric pressure. The current densities were 2 and 1.2 A cm{sup -2} at a terminal voltage of 1.9 V for Nafion-SiO{sub 2} and Nafion 115, respectively, at 100{sup o}C and atmospheric pressure. By increasing the temperature up to 120{sup o}C, the performance of Nafion 115 drastically decreased; whereas, the cell based on Nafion-SiO{sub 2} membrane showed a further increase of performance, especially when the pressure was increased to 3 bar abs (2.1 A cm{sup -2} at 1.9 V). (author)

  6. Heat-driven thermoacoustic cryocooler operating at liquid hydrogen temperature with a unique coupler

    Science.gov (United States)

    Hu, J. Y.; Luo, E. C.; Li, S. F.; Yu, B.; Dai, W.

    2008-05-01

    A heat-driven thermoacoustic cryocooler is constructed. A unique coupler composed of a tube, reservoir, and elastic diaphragm is introduced to couple a traveling-wave thermoacoustic engine (TE) and two-stage pulse tube refrigerator (PTR). The amplitude of the pressure wave generated in the engine is first amplified in the coupler and the wave then passes into the refrigerator to pump heat. The TE uses nitrogen as its working gas and the PTR still uses helium as its working gas. With this coupler, the efficiency of the system is doubled. The engine and coupler match at a much lower operating frequency, which is of great benefit for the PTR to obtain a lower cooling temperature. The coupling place between the coupler and engine is also optimized. The onset problem is effectively solved. With these improvements, the heat-driven thermoacoustic cryocooler reaches a lowest temperature of 18.1K, which is the demonstration of heat-driven thermoacoustic refrigeration technology used for cooling at liquid hydrogen temperatures.

  7. Determining Role of Temperature Chart while Evaluating Specific Expenses of Organic Fuel

    Directory of Open Access Journals (Sweden)

    A. P. Nesenchouk

    2009-01-01

    Full Text Available The paper considers designing principles of operational space continuous heating and heat-treating furnaces at mechanical engineering, automotive and tractor enterprises in theRepublicofBelarus. A role of temperature chart on heating metallic charge while evaluating specific expenses of organic fuel in heating and heat-treating furnaces of mechanical engineering, automotive and tractor industries. 

  8. 40 CFR 86.1229-85 - Dynamometer load determination and fuel temperature profile.

    Science.gov (United States)

    2010-07-01

    ... testing to reproduce fuel and vapor temperature behavior over the specified driving schedule. The design... § 86.1207-96(e) and (f), and a driver's aid, which shall be configured to provide the test driver with... surface. The driver's aid shall be started and the vehicle operated over the driving cycle specified...

  9. Experimental design, operation, and results of a 4 kW high temperature steam electrolysis experiment

    Science.gov (United States)

    Zhang, Xiaoyu; O'Brien, James E.; Tao, Greg; Zhou, Can; Housley, Gregory K.

    2015-11-01

    High temperature steam electrolysis (HTSE) is a promising technology for large-scale hydrogen production. However, research on HTSE performance above the kW level is limited. This paper presents the results of 4 kW HTSE long-term test completed in a multi-kW test facility recently developed at the Idaho National Laboratory (INL). The 4 kW HTSE unit consisted of two solid oxide electrolysis stacks electrically connected in parallel, each of which included 40 electrode-supported planar cells. A current density of 0.41 A cm-2 was used for the long-term operating at a constant current mode, resulting in a theoretical hydrogen production rate about 23 slpm. A demonstration of 830 h stable operation was achieved with a degradation rate of 3.1% per 1000 h. The paper also includes detailed descriptions of the piping layout, steam generation and delivery system, test fixture, heat recuperation system, hot zone, instrumentation, and operating conditions. This successful demonstration of multi-kW scale HTSE unit will help to advance the technology toward near-term commercialization.

  10. Determination of temperature dependency of material parameters for lead-free alkali niobate piezoceramics by the inverse method

    Directory of Open Access Journals (Sweden)

    K. Ogo

    2016-06-01

    Full Text Available Sodium potassium niobate (NKN piezoceramics have been paid much attention as lead-free piezoelectric materials in high temperature devices because of their high Curie temperature. The temperature dependency of their material parameters, however, has not been determined in detail up to now. For this purpose, we exploit the so-called Inverse Method denoting a simulation-based characterization approach. Compared with other characterization methods, the Inverse Method requires only one sample shape of the piezoceramic material and has further decisive advantages. The identification of material parameters showed that NKN is mechanically softer in shear direction compared with lead zirconate titanate (PZT at room temperature. The temperature dependency of the material parameters of NKN was evaluated in the temperature range from 30 °C to 150 °C. As a result, we figured out that dielectric constants and piezoelectric constants show a monotonous and isotropic increment with increasing temperature. On the other hand, elastic stiffness constant c 44 E of NKN significantly decreased in contrast to other elastic stiffness constants. It could be revealed that the decrement of c 44 E is associated with an orthorhombic-tetragonal phase transition. Furthermore, ratio of elastic compliance constants s 44 E / s 33 E exhibited similar temperature dependent behavior to the ratio of piezoelectric constants d15/d33. It is suspected that mechanical softness in shear direction is one origin of the large piezoelectric shear mode of NKN. Our results show that NKN are suitable for high temperature devices, and that the Inverse Method should be a helpful approach to characterize material parameters under their practical operating conditions for NKN.

  11. Determination of Trace Mercury by Catalytic Solid Substrate-room Temperature Phosphorimetry

    Institute of Scientific and Technical Information of China (English)

    Jia Ming LIU; Yun Xiong WU; Shao Xian LIN; Fei Ming LI; Xiu Mei SHI; Zhong Bin SHI; Guo Hui ZHU; Zhi Ming LI; Xiao Mei HUANG

    2006-01-01

    A new highly sensitive method (detection limit: 4.1 ag spot-1, sample volume: 0.4 μL spot-1) for the determination of trace Hg2+ by catalytic solid substrate-room temperature phosphorimetry has been established in this paper. This method has been successfully applied to determine trace Hg2+ in water.

  12. Ruby fluorescence lifetime measurements for temperature determinations at high (p, T)

    Science.gov (United States)

    Bauer, Johannes D.; Bayarjargal, Lkhamsuren; Winkler, Björn

    2012-06-01

    The lifetime of the ruby R1 fluorescence line was measured as a function of pressure (up to about 20 GPa) and temperature (550 K) in an externally heated diamond anvil cell (DAC). At constant temperatures, the lifetime is increasing linearly with increasing pressure. The slope of the pressure dependence is constant up to a temperature of 450 K and it is decreasing at higher temperatures. At constant pressure, the lifetime is exponentially decreasing with increasing temperature. The (p, T)-dependence can be parametrized by the combination of a linear and an exponential function. This allows an accurate p, T-determination by the combination of fluorescence spectroscopy using Sm2+-doped strontium tetraborate and lifetime measurements of ruby, as the energy of the Sm2+ fluorescence is nearly temperature-independent.

  13. The Determination of Stresses in Wire-Drawing Operation Using the ...

    African Journals Online (AJOL)

    The Determination of Stresses in Wire-Drawing Operation Using the Finite ... distribution of stresses and pressures set up at various cross-sections of a ... die angle, length and blank radius and compared with the exact solution on a table.

  14. DETERMINATION OF OPERATING FIELDS OF TOLERANCES OF HYDRAULIC SYSTEMS PARAMETERS FOR AIRCRAFT BOARD COMPUTER COMPLEX

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available To determine the operating fields of the tolerances of hydraulic systems parameters for various conditions of work and phases of flight given mathematical relationships and the results obtained in Mathcad in analytical form for the board computer system.

  15. Analysis of the linearised observation operator in a soil moisture and temperature analysis scheme

    Science.gov (United States)

    Dharssi, I.; Candy, B.; Steinle, P.

    2015-06-01

    Several weather forecasting agencies have developed advanced land data assimilation systems that, in principle, can analyse any model land variable. Such systems can make use of a wide variety of observation types, such as screen level (2 m above the surface) observations and satellite based measurements of surface soil moisture and skin temperature. Indirect measurements can be used and information propagated from the surface into the deeper soil layers. A key component of the system is the calculation of the linearised observation operator matrix (Jacobian matrix) which describes the link between the observations and the land surface model variables. The elements of the Jacobian matrix (Jacobians) are estimated using finite difference by performing short model forecasts with perturbed initial conditions. The calculated Jacobians show that there can be strong coupling between the screen level and the soil. The coupling between the screen level and surface soil moisture is found to be due to a number of processes including bare soil evaporation, soil thermal conductivity as well as transpiration by plants. Therefore, there is significant coupling both during the day and at night. The coupling between the screen level and root-zone soil moisture is primarily through transpiration by plants. Therefore the coupling is only significant during the day and the vertical variation of the coupling is modulated by the vegetation root depths. The calculated Jacobians that link screen level temperature to model soil temperature are found to be largest for the topmost model soil layer and become very small for the lower soil layers. These values are largest during the night and generally positive in value. It is found that the Jacobians that link observations of surface soil moisture to model soil moisture are strongly affected by the soil hydraulic conductivity. Generally, for the Joint UK Land Environment Simulator (JULES) land surface model, the coupling between the surface

  16. Segregating variation for temperature-dependent sex determination in a lizard.

    Science.gov (United States)

    Rhen, T; Schroeder, A; Sakata, J T; Huang, V; Crews, D

    2011-04-01

    Temperature-dependent sex determination (TSD) was first reported in 1966 in an African lizard. It has since been shown that TSD occurs in some fish, several lizards, tuataras, numerous turtles and all crocodilians. Extreme temperatures can also cause sex reversal in several amphibians and lizards with genotypic sex determination. Research in TSD species indicates that estrogen signaling is important for ovary development and that orthologs of mammalian genes have a function in gonad differentiation. Nevertheless, the mechanism that actually transduces temperature into a biological signal for ovary versus testis development is not known in any species. Classical genetics could be used to identify the loci underlying TSD, but only if there is segregating variation for TSD. Here, we use the 'animal model' to analyze inheritance of sexual phenotype in a 13-generation pedigree of captive leopard geckos, Eublepharis macularius, a TSD reptile. We directly show genetic variance and genotype-by-temperature interactions for sex determination. Additive genetic variation was significant at a temperature that produces a female-biased sex ratio (30°C), but not at a temperature that produces a male-biased sex ratio (32.5°C). Conversely, dominance variance was significant at the male-biased temperature (32.5°C), but not at the female-biased temperature (30°C). Non-genetic maternal effects on sex determination were negligible in comparison with additive genetic variance, dominance variance and the primary effect of temperature. These data show for the first time that there is segregating variation for TSD in a reptile and consequently that a quantitative trait locus analysis would be practicable for identifying the genes underlying TSD.

  17. Temperature Trends in Coal Char Combustion under Oxy-fuel Conditions for the Determination of Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Samira [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hecht, Ethan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-08-01

    Oxy-fuel combustion technology with carbon capture and storage could significantly reduce global CO2 emissions, a greenhouse gas. Implementation can be aided by computational fluid dynamics (CFD) simulations, which require an accurate understanding of coal particle kinetics as they go through combustion in a range of environments. To understand the kinetics of pulverized coal char combustion, a heated flow reactor was operated under a wide range of experimental conditions. We varied the environment for combustion by modifying the diluent gas, oxygen concentration, gas flow rate, and temperature of the reactor/reacting gases. Measurements of reacting particle temperatures were made for a sub-bituminous and bituminous coal char, in environments with CO2 or N2 as the diluent gas, with 12, 24, and 36 vol-% oxygen concentration, at 50, 80, 100, and 200 standard liters per minute flowing through the reactor, reactor temperatures of 1200, 1400 K, at pressures slightly above atmospheric. The data shows consistent increasing particle temperature with increased oxygen concentration, reactor temperature and higher particle temperatures for N2 diluent than CO2. We also see the effects of CO2 gasification when different ranks of coal are used, and how the reduction in the temperature due to the CO2 diluent is greater for the coal char that has higher reactivity. Quantitative measurements for temperature are not yet complete due to ongoing calibration of detection systems.

  18. Determining Maximum Photovoltaic Penetration in a Distribution Grid considering Grid Operation Limits

    DEFF Research Database (Denmark)

    Kordheili, Reza Ahmadi; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

    2014-01-01

    High penetration of photovoltaic panels in distribution grid can bring the grid to its operation limits. The main focus of the paper is to determine maximum photovoltaic penetration level in the grid. Three main criteria were investigated for determining maximum penetration level of PV panels...... for this grid: even distribution of PV panels, aggregation of panels at the beginning of each feeder, and aggregation of panels at the end of each feeder. Load modeling is done using Velander formula. Since PV generation is highest in the summer due to irradiation, a summer day was chosen to determine maximum...

  19. AATSR - Precise Sea-Surface Temperature for Climate Monitoring and for Operational Applications

    Science.gov (United States)

    Llewellyn-Jones, David; Corlett, Gary; Donlon, Craig; Stark, John

    The Advanced Along-Track Scanning Radiometer (AATSR) is an imaging radiometer specifi- cally designed to measure Sea-Surface Temperature (SST) to the demanding levels of accuracy and stability required for climate research. AATSR, which has been operating continuously on ESA's Envisat Satellite since its launch in 2002, achieves the required levels of accuracy on account of its unique dual view, whereby each terrestrial scene is viewed twice, once at nadir and then through an inclined path which uses a different atmospheric path-length, thereby providing a direct observation of atmospheric effects, leading to an exceptionally accurate atmospheric correction. This feature is accompanied by an advanced calibration system combined with excellent optical and thermal designs. Recent rigorous and extensive comparisons with in situ data have shown that, for most of the global oceans, AATSR can achieve and accuracy of around 0.2o C with high stability, which has qualified them for use in climate analysis schemes. Because AATSR is the third sensor in a near-continuous series which started with the launch of ATSR-1 on ERS-1 satellite in 1991, there is a time-series of 16+ years of climate standard SSTs which have recently been re-processed and are now becoming available to the World-wide user community from data centres in Europe. SST data from AATSR have been included in the suite of operational SST products generated by the GODAE/GHRSST Pilot Project, on a timescale needed by operational users and in a format which allows easy ingestion and error estimates for data from AATSR and most of the other sensors currently providing SST measurements from space. Within the GODAE/GHRSST data-products, AATSR SST data are generally regarded as the benchmark for accuracy and are used to provide bias corrections for data from the other sensors, which often have superior coverage, thus exploiting synergistically the complementary qualities if the different data-sets. The UK Met Office

  20. Simulating potential structural and operational changes for Detroit Dam on the North Santiam River, Oregon, for downstream temperature management

    Science.gov (United States)

    Buccola, Norman L.; Rounds, Stewart A.; Sullivan, Annett B.; Risley, John C.

    2012-01-01

    Detroit Dam was constructed in 1953 on the North Santiam River in western Oregon and resulted in the formation of Detroit Lake. With a full-pool storage volume of 455,100 acre-feet and a dam height of 463 feet, Detroit Lake is one of the largest and most important reservoirs in the Willamette River basin in terms of power generation, recreation, and water storage and releases. The U.S. Army Corps of Engineers operates Detroit Dam as part of a system of 13 reservoirs in the Willamette Project to meet multiple goals, which include flood-damage protection, power generation, downstream navigation, recreation, and irrigation. A distinct cycle in water temperature occurs in Detroit Lake as spring and summer heating through solar radiation creates a warm layer of water near the surface and isolates cold water below. Controlling the temperature of releases from Detroit Dam, therefore, is highly dependent on the location, characteristics, and usage of the dam's outlet structures. Prior to operational changes in 2007, Detroit Dam had a well-documented effect on downstream water temperature that was problematic for endangered salmonid fish species, releasing water that was too cold in midsummer and too warm in autumn. This unnatural seasonal temperature pattern caused problems in the timing of fish migration, spawning, and emergence. In this study, an existing calibrated 2-dimensional hydrodynamic water-quality model [CE-QUAL-W2] of Detroit Lake was used to determine how changes in dam operation or changes to the structural release points of Detroit Dam might affect downstream water temperatures under a range of historical hydrologic and meteorological conditions. The results from a subset of the Detroit Lake model scenarios then were used as forcing conditions for downstream CE-QUAL-W2 models of Big Cliff Reservoir (the small reregulating reservoir just downstream of Detroit Dam) and the North Santiam and Santiam Rivers. Many combinations of environmental, operational, and

  1. Experimental determination of the temperature dependence of water activities for a selection of aqueous organic solutions

    Directory of Open Access Journals (Sweden)

    G. Ganbavale

    2014-05-01

    Full Text Available This work presents experimental data of the temperature dependence of water activity in aqueous organic solutions relevant for tropospheric conditions (200–273 K. Water activity (aw at low temperatures (T is a crucial parameter for predicting homogeneous ice nucleation. We investigated temperature dependent water activities, ice freezing and melting temperatures of solutions, and vapour pressures of a selection of atmospherically relevant aqueous organic systems. To measure aw over a wide composition range and with a focus on low temperatures, we use various aw measurement techniques and instruments: a dew point water activity meter, an electrodynamic balance (EDB, differential scanning calorimetry (DSC, and a setup to measure the total gas phase pressure at equilibrium over aqueous solutions. Water activity measurements were performed for aqueous multicomponent and multifunctional organic mixtures containing the functional groups typically found in atmospheric organic aerosols, such as hydroxyl, carboxyl, ketone, ether, ester, and aromatic groups. The aqueous organic systems studied at several fixed compositions over a considerable temperature range differ significantly in their temperature dependence. Aqueous organic systems of 1,4-butanediol and methoxyacetic acid show a moderate decrease in aw with decreasing temperature. The aqueous M5 system (a multicomponent system containing five different dicarboxylic acids and aqueous 2-(2-ethoxyethoxyethanol solutions both show a strong increase of water activity with decreasing temperature at high solute concentrations for TTaw can be reversed at low temperatures and that linear extrapolations of high temperature data may lead to erroneous predictions. To avoid this, experimentally determined aw at low temperature are needed to improve thermodynamic models towards lower temperatures and for improved predictions of the ice nucleation ability of organic–water systems.

  2. Designing Nanoscale Precipitates in Novel Cobalt-based Superalloys to Improve Creep Resistance and Operating Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dunand, David C. [Northwestern Univ., Evanston, IL (United States); Seidman, David N. [Northwestern Univ., Evanston, IL (United States); Wolverton, Christopher [Northwestern Univ., Evanston, IL (United States); Saal, James E. [Northwestern Univ., Evanston, IL (United States); Bocchini, Peter J. [Northwestern Univ., Evanston, IL (United States); Sauza, Daniel J. [Northwestern Univ., Evanston, IL (United States)

    2014-10-01

    High-temperature structural alloys for aerospace and energy applications have long been dominated by Ni-base superalloys, whose strength and creep resistance can be attributed to microstructures consisting of a large volume fraction of ordered (L12) γ'-precipitates embedded in a disordered’(f.c.c.) γ-matrix. These alloys exhibit excellent mechanical behavior and thermal stability, but after decades of incremental improvement are nearing the theoretical limit of their operating temperatures. Conventional Co-base superalloys are solid-solution or carbide strengthened; although they see industrial use, these alloys are restricted to lower-stress applications because the absence of an ordered intermetallic phase places an upper limit on their mechanical performance. In 2006, a γ+γ' microstructure with ordered precipitates analogous to (L12) Ni3Al was first identified in the Co-Al-W ternary system, allowing, for the first time, the development of Co-base alloys with the potential to meet or even exceed the elevated-temperature performance of their Ni-base counterparts. The potential design space for these alloys is complex: the most advanced Ni-base superalloys may contain as many as 8-10 minor alloying additions, each with a specified purpose such as raising the γ' solvus temperature or improving creep strength. Our work has focused on assessing the effects of alloying additions on microstructure and mechanical behavior of γ'-strengthened Co-base alloys in an effort to lay the foundations for understanding this emerging alloy system. Investigation of the size, morphology, and composition of γ' and other relevant phases is investigated utilizing scanning electron microscopy (SEM) and 3-D picosecond ultraviolet local electrode atom probe tomography (APT). Microhardness, compressive yield stress at ambient and elevated temperatures, and compressive high-temperature creep measurements are employed to

  3. Reliability issues for a bolometer detector for ITER at high operating temperatures.

    Science.gov (United States)

    Meister, H; Kannamüller, M; Koll, J; Pathak, A; Penzel, F; Trautmann, T; Detemple, P; Schmitt, S; Langer, H

    2012-10-01

    The first detector prototypes for the ITER bolometer diagnostic featuring a 12.5 μm thick Pt-absorber have been realized and characterized in laboratory tests. The results show linear dependencies of the calibration parameters and are in line with measurements of prototypes with thinner absorbers. However, thermal cycling tests up to 450 °C of the prototypes with thick absorbers demonstrated that their reliability at these elevated operating temperatures is not yet sufficient. Profilometer measurements showed a deflection of the membrane hinting to stresses due to the deposition processes of the absorber. Finite element analysis (FEA) managed to reproduce the deflection and identified the highest stresses in the membrane in the region around the corners of the absorber. FEA was further used to identify changes in the geometry of the absorber with a positive impact on the intrinsic stresses of the membrane. However, further improvements are still necessary.

  4. The calibration and operation of a constant-temperature crossed-wire probe in supersonic flow

    Science.gov (United States)

    Fernando, E. M.; Donovan, J. F.; Smits, A. J.

    1987-01-01

    The calibration and operation of a constant-temperature crossed-wire probe in supersonic flow is considered. Crossed-wire probes offer considerable advantages over single, inclined wires: the kinematic shear stress can be derived from a single point measurement; the rms quantities can be derived from the same measurement, and the instantaneous quantities can be obtained as a continuous function of time. However, using a crossed-wire probe in supersonic flow is subject to the following practical difficulties: the problem of flow interference, where the shock waves from one wire and its supports interfere with the flow over the other wire; the necessity for high frequency response to resolve the spectral content, and the sensitivity of the results to small changes in the calibration constants. In the present contribution, each of these problems is addressed. Practical solutions are suggested, and some encouraging results are presented.

  5. Effect of Operating Temperature on Structure Properties of TICX Nanoparticle Coating Applied by Pacvd

    Science.gov (United States)

    Shanaghi, Ali; Sabour Rouhaghdam, Ali Reza; Ahangarani, Shahrokh; Moradi, Hadi; Mohammadi, Ali

    Titanium carbide (TiC) is a widely used hard coating to improve the wear resistance and lifetime of tools because of its outstanding properties such as high melting point, high hardness, corrosion resistance and abrasion resistance. These properties were drastically improved by using nanotechnology. So in this project, TiCx was applied on hot-working die steel (H11) by Plasma CVD (PACVD). The effect of operating temperatures on TiCx structure properties have been studies by typical and advanced analyses methods such as SEM, XRD, FTIR and Raman. The best properties of TiCx nanoparticle, such as nanostructure, mechanical properties and chemical properties, were obtained at 480 °C.

  6. Modeling and Simulation of - and Silicon Germanium-Base Bipolar Transistors Operating at a Wide Range of Temperatures.

    Science.gov (United States)

    Shaheed, M. Reaz

    1995-01-01

    Higher speed at lower cost and at low power consumption is a driving force for today's semiconductor technology. Despite a substantial effort toward achieving this goal via alternative technologies such as III-V compounds, silicon technology still dominates mainstream electronics. Progress in silicon technology will continue for some time with continual scaling of device geometry. However, there are foreseeable limits on achievable device performance, reliability and scaling for room temperature technologies. Thus, reduced temperature operation is commonly viewed as a means for continuing the progress towards higher performance. Although silicon CMOS will be the first candidate for low temperature applications, bipolar devices will be used in a hybrid fashion, as line drivers or in limited critical path elements. Silicon -germanium-base bipolar transistors look especially attractive for low-temperature bipolar applications. At low temperatures, various new physical phenomena become important in determining device behavior. Carrier freeze-out effects which are negligible at room temperature, become of crucial importance for analyzing the low temperature device characteristics. The conventional Pearson-Bardeen model of activation energy, used for calculation of carrier freeze-out, is based on an incomplete picture of the physics that takes place and hence, leads to inaccurate results at low temperatures. Plasma -induced bandgap narrowing becomes more pronounced in device characteristics at low temperatures. Even with modern numerical simulators, this effect is not well modeled or simulated. In this dissertation, improved models for such physical phenomena are presented. For accurate simulation of carrier freeze-out, the Pearson-Bardeen model has been extended to include the temperature dependence of the activation energy. The extraction of the model is based on the rigorous, first-principle theoretical calculations available in the literature. The new model is shown

  7. 46 CFR 54.25-20 - Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies...

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Low temperature operation-ferritic steels with properties enhanced by heat treatment (modifies UHT-5(c), UHT-6, UHT-23, and UHT-82). 54.25-20 Section 54.25... VESSELS Construction With Carbon, Alloy, and Heat Treated Steels § 54.25-20 Low temperature...

  8. The dew point temperature as a criterion for optimizing the operating conditions of proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Berning, Torsten

    2012-01-01

    be predicted a priori with the aid of these diagrams. Finally, guidelines for the desired cell operating temperature based on the expected dew point temperatures are developed. In the current work these guidelines are limited to the interdigitated flow field design, and they are likely to be different...

  9. APPLICATION DIMENSIONAL AND SIMILARITY THEORY IN DETERMINING THE PARAMETERS AND OPERATING MODES OF SOIL CULTIVATING MACHINES

    Directory of Open Access Journals (Sweden)

    Shhirov V. N.

    2015-06-01

    Full Text Available The article presents a study of parameters and modes of operation of machines for soil cultivation. In determining the parameters and modes of operation of machinery for tillage we have applied the theory of similarity and dimensions of physical quantities. We have obtained the regularities of disclosing the relationship of the parameters from the medium to the energy characteristics of the process. As the initial data we used test protocols of machines for soil cultivation (Central - Black Earth, Kubanskaya, Sibirskaya, of North - Caucasion MIS, RosNIITiM : KPI - 3.8, AРC - 3.9, AKV - 4, AKM - 6 - V, AMP - 4 APC - 4 A, AРC - 10 APR - 4.4, APU - 6.5 APSH - 6 , CNC - 6.0, CSТ - 3.8, APC - 4. We defined the formula оf dimension parameters and modes of operation of machines for soil cultivation and properties of soil (traction resistance, depth, width, speed, hardness of the soil, acceleration. Based on dimension theory we have received similarity criteria. Based on the correlation analysis and the least squares method we determined the nature of addiction and the coefficients for it. We have also received a graph for determining the operating modes and parameters of machines for soil cultivation

  10. Room-temperature continuous-wave operation of Ti:sapphire buried channel-waveguide lasers fabricated via proton implantation

    NARCIS (Netherlands)

    Grivas, C.; Shepherd, D.P.; Eason, R.W.; Laversenne, L.; Moretti, P.; Borca, C.N.; Pollnau, M.

    2006-01-01

    Fabrication and laser operation of proton-implanted Ti:sapphire buried channel waveguides is reported for the first time to our knowledge. Without any postimplantation annealing of the structures, continuous laser operation near 780 nm was demonstrated at room temperature at an absorbed pump power t

  11. Determination of absorption coefficients of glasses at high tempera-tures, by measuring the thermal emission

    OpenAIRE

    Loenen, E.; Van der Tempel, L.

    1996-01-01

    An experimental setup built in 1995 measures the spectral absorptioncoefficient of glass as a function of temperature and wavelength bythe emissive method. The setup was improved, as well as the softwarefor processing the measurement data. The measurement results of quartzwere validated by comparison with several literature sources. Theabsorption spectra of Philips 360, GE 180, Schott 8486 Suprax, Corning1724 and Philips 441 glass were determined as a function of temperature.

  12. The determination of the operating range of a twin-grip control yoke through biomechanical means

    Science.gov (United States)

    Gaertner, K. P.

    1978-01-01

    A twin-grip control yoke was designed as an ergonomic case study that allows dual axis control inputs, both axes being rotational. Inputs are effected by rotating the grips. How the handles were designed with respect to their shape and size and how the angular range of the control yoke in both rotational axes was evaluated. The control yoke which requires two-hand operation was tested to determine its operating range. The intention of this investigation was to find out the optimal form of the control yoke and the maximum permissible range in both rotating axes. In these experiments controls had no spring resistance.

  13. The influence of the stray-light component in determining coronal temperature structures

    Institute of Scientific and Technical Information of China (English)

    HAO Juan; ZHANG Mei

    2009-01-01

    We use a few solar partial eclipse observations made by XRT/Hinode to estimate the influence of stray-light component in determining coronal temperature structures. Our analysis shows that the stray light will largely affect the estimation of coronal temperature and change the estimated temperature structure in one coronal hole region. The stray lights mildly influence the estimated temperatures in one quiet Sun region and do not change the estimated temperature structure. This implies that the influence of stray lights differs from one region to another, and definitely needs to be considered in some regions. Whereas a carefully estimated point-spread-function Is needed to remove the stray light component, our study shows that by a simple approach such as subtracting the average intensity of distant (e.g. >1.4 solar radius) points from the data values, the influence of stray light can be largely removed, at least for the two regions we study here.

  14. The influence of the stray-light component in determining coronal temperature structures

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    We use a few solar partial eclipse observations made by XRT/Hinode to estimate the influence of stray-light component in determining coronal temperature structures. Our analysis shows that the stray light will largely affect the estimation of coronal temperature and change the estimated temperature structure in one coronal hole region. The stray lights mildly influence the estimated temperatures in one quiet Sun region and do not change the estimated temperature structure. This implies that the influence of stray lights differs from one region to another, and definitely needs to be considered in some regions. Whereas a carefully estimated point-spread-function is needed to remove the stray light component, our study shows that by a simple approach such as subtracting the average intensity of distant (e.g. >1.4 solar radius) points from the data values, the influence of stray light can be largely removed, at least for the two regions we study here.

  15. Preliminary operational results of the low-temperature solar industrial process heat field tests

    Energy Technology Data Exchange (ETDEWEB)

    Kutscher, C.F.; Davenport, R.L.

    1980-06-01

    Six solar industrial process heat field tests have been in operation for a year or more - three are hot water systems and three are hot air systems. All are low-temperature projects (process heat at temperatures below 212/sup 0/F). Performance results gathered by each contractor's data acquisition system are presented and project costs and problems encountered are summarized. Flat-plate, evacuated-tube, and line-focus collectors are all represented in the program, with collector array areas ranging from 2500 to 21,000 ft/sup 2/. Collector array efficiencies ranged from 12% to 36% with net system efficiencies from 8% to 33%. Low efficiencies are attributable in some cases to high thermal losses and, for the two projects using air collectors, are due in part to high parasitic power consumption. Problems have included industrial effluents on collectors, glazing and absorber surface failures, excessive thermal losses, freezing and overheating, control problems, and data acquisition system failure. With design and data acquisition costs excluded costs of the projects ranged from $25/ft/sup 2/ to $87/ft/sup 2/ and $499/(MBtu/yr) to $1537/(MBtu/yr).

  16. Temperature stable operation of YCOB crystal for giant-pulse green microlaser.

    Science.gov (United States)

    Kausas, Arvydas; Loiseau, Pascal; Aka, Gerard; Zheng, Yanqing; Zheng, Lihe; Taira, Takunori

    2017-03-20

    In this work the performance of two yttrium calcium oxyborate (YCOB) crystals made by Czochralski and Bridgman growth process was measured. By using high peak power, passively Q-switched Nd3+:YAG/Cr4+:YAG microlaser, high conversion second harmonic generation efficiency were obtained. Laser pulses at 532 nm with 1.14 mJ energy and 223 ps duration were obtained with a 15-mm long YCOB crystal that was grown by Bridgman method. The conversion efficiency was 70.2%, comparable with the conversion efficiency of 72.8% that was achieved with 10-mm long lithium triborate (LBO) nonlinear crystal. Also, for the first time, experimental data on temperature tuning in type I YCOB crystal was measured with linear slope in 200°C temperature range equal to -0.057%/°C and -0.064%/°C for the Czochralski and Bridgman grown crystals, respectively. Such YCOB nonlinear crystal can become a serious option for developing laser sources with high-peak power at high repetition rate that can operate in harsh environment.

  17. InSb Mid-Infrared Photon Detector for Room-Temperature Operation

    Science.gov (United States)

    Ueno, Koichiro; Gomes Camargo, Edson; Katsumata, Takashi; Goto, Hiromasa; Kuze, Naohiro; Kangawa, Yoshihiro; Kakimoto, Koichi

    2013-09-01

    We developed a small InSb mid-infrared (2-7 µm wavelength range) photon detector that operates at room temperature. The photodiode was made from (hetero epitaxial) InSb layers that were grown on a semi-insulating GaAs substrate by molecular beam epitaxy. To suppress the effects of the diffusion current of the p-i-n photodiode, we used an AlInSb barrier layer that raises the resistance of the photodiode. We also optimized the device's doping concentration and the infrared incidence window structure. These optimization steps realized high photoelectric current output in a room-temperature environment. We also increased the signal-to-noise ratio of the detector by connecting multiple photodiodes in series. The size of this detector is 1.9×2.7×0.4 mm3 and the detectivity is 2.8×108 cm Hz1/2/W at 300 K. This is a practical IR detector that can be used in general signal amplification ICs.

  18. Feasibility study of SiGHT: a novel ultra low background photosensor for low temperature operation

    Science.gov (United States)

    Wang, Y.; Fan, A.; Fiorillo, G.; Galbiati, C.; Guan, M. Y.; Korga, G.; Pantic, E.; Razeto, A.; Renshaw, A.; Rossi, B.; Suvorov, Y.; Wang, H.; Yang, C. G.

    2017-02-01

    Rare event search experiments, such as those searching for dark matter and observations of neutrinoless double beta decay, require ultra low levels of radioactive background for unmistakable identification. In order to reduce the radioactive background of detectors used in these types of event searches, low background photosensors are required, as the physical size of these detectors become increasing larger, and hence the number of such photosensors used also increases rapidly. Considering that most dark matter and neutrinoless double beta decay experiments are turning towards using noble liquids as the target choice, liquid xenon and liquid argon for instance, photosensors that can work well at cryogenic temperatures are required, 165 K and 87 K for liquid xenon and liquid argon, respectively. The Silicon Geiger Hybrid Tube (SiGHT) is a novel photosensor designed specifically for use in ultra low background experiments operating at cryogenic temperatures. It is based on the proven photocathode plus silicon photomultiplier (SiPM) hybrid technology and consists of very few other, but also ultra radio-pure, materials like fused silica and silicon for the SiPM. The introduction of the SiGHT concept, as well as a feasibility study for its production, is reported in this paper.

  19. Evaluation of Land Surface Temperature Operationally Retrieved from Korean Geostationary Satellite (COMS Data

    Directory of Open Access Journals (Sweden)

    A-Ra Cho

    2013-08-01

    Full Text Available We evaluated the precision of land surface temperature (LST operationally retrieved from the Korean multipurpose geostationary satellite, Communication, Ocean and Meteorological Satellite (COMS. The split-window (SW-type retrieval algorithm was developed through radiative transfer model simulations under various atmospheric profiles, satellite zenith angles, surface emissivity values and surface lapse rate conditions using Moderate Resolution Atmospheric Transmission version 4 (MODTRAN4. The estimation capabilities of the COMS SW (CSW LST algorithm were evaluated for various impacting factors, and the retrieval accuracy of COMS LST data was evaluated with collocated Moderate Resolution Imaging Spectroradiometer (MODIS LST data. The surface emissivity values for two SW channels were generated using a vegetation cover method. The CSW algorithm estimated the LST distribution reasonably well (averaged bias = 0.00 K, Root Mean Square Error (RMSE = 1.41 K, correlation coefficient = 0.99; however, the estimation capabilities of the CSW algorithm were significantly impacted by large brightness temperature differences and surface lapse rates. The CSW algorithm reproduced spatiotemporal variations of LST comparing well to MODIS LST data, irrespective of what month or time of day the data were collected from. The one-year evaluation results with MODIS LST data showed that the annual mean bias, RMSE and correlation coefficient for the CSW algorithm were −1.009 K, 2.613 K and 0.988, respectively.

  20. Integrated Operating Scenario to Achieve 100-Second, High Electron Temperature Discharge on EAST

    Science.gov (United States)

    Qian, Jinping; Gong, Xianzu; Wan, Baonian; Liu, Fukun; Wang, Mao; Xu, Handong; Hu, Chundong; Wang, Liang; Li, Erzhong; Zeng, Long; Ti, Ang; Shen, Biao; Lin, Shiyao; Shao, Linming; Zang, Qing; Liu, Haiqing; Zhang, Bin; Sun, Youwen; Xu, Guosheng; Liang, Yunfeng; Xiao, Bingjia; Hu, Liqun; Li, Jiangang; EAST Team

    2016-05-01

    Stationary long pulse plasma of high electron temperature was produced on EAST for the first time through an integrated control of plasma shape, divertor heat flux, particle exhaust, wall conditioning, impurity management, and the coupling of multiple heating and current drive power. A discharge with a lower single null divertor configuration was maintained for 103 s at a plasma current of 0.4 MA, q95 ≈7.0, a peak electron temperature of >4.5 keV, and a central density ne(0)˜2.5×1019 m-3. The plasma current was nearly non-inductive (Vloop heating at 140 GHz, and 0.4 MW modulated neutral deuterium beam injected at 60 kV. This progress demonstrated strong synergy of electron cyclotron and lower hybrid electron heating, current drive, and energy confinement of stationary plasma on EAST. It further introduced an example of integrated “hybrid” operating scenario of interest to ITER and CFETR. supported by the National Magnetic Confinement Fusion Science Foundation of China (Nos. 2015GB102000 and 2014GB103000)

  1. Fabrication of room temperature continuous-wave operation GaN-based ultraviolet laser diodes

    Science.gov (United States)

    Zhao, Degang; Yang, Jing; Liu, Zongshun; Chen, Ping; Zhu, Jianjun; Jiang, Desheng; Shi, Yongsheng; Wang, Hai; Duan, Lihong; Zhang, Liqun; Yang, Hui

    2017-06-01

    Two kinds of continuous-wave GaN-based ultraviolet laser diodes (LDs) operated at room temperature and with different emission wavelengths are demonstrated. The LDs epitaxial layers are grown on GaN substrate by metalorganic chemical vapor deposition, with a 10 × 600 μm2 ridge waveguide structure. The electrical and optical characteristics of the ultraviolet LDs are investigated under direct-current injection at room temperature. The stimulated emission peak wavelength of first LD is 392.9 nm, the threshold current density and voltage is 1.5 kA/cm2 and 5.0 V, respectively. The output light power is 80 mW under the 4.0 kA/cm2 injection current density. The stimulated emission peak wavelength of second LD is 381.9 nm, the threshold current density the voltage is 2.8 kA/cm2 and 5.5 V, respectively. The output light power is 14 mW under a 4.0 kA/cm2 injection current density. Projects the supported by the National Key R&D Program of China (Nos. 2016YFB0401801, 2016YFB0400803), the National Natural Science Foundation of China (Nos. 61674138, 61674139, 61604145, 61574135, 61574134, 61474142, 61474110, 61377020, 61376089), the Science Challenge Project (No. JCKY2016212A503), and the One Hundred Person Project of the Chinese Academy of Sciences.

  2. Determinants of longer duration of endotracheal intubation after adult cardiac operations.

    Science.gov (United States)

    Bando, K; Sun, K; Binford, R S; Sharp, T G

    1997-04-01

    Poor pulmonary reserve is a risk factor that is used to exclude some patients from major operations. However, the value of routine spirometry in patients undergoing cardiac operations has not been widely evaluated. The outcomes of 586 consecutive adult patients undergoing cardiac operations were reviewed retrospectively to assess predictors of longer duration of endotracheal intubation. By univariate analysis, congestive failure (p endotracheal intubation. Spirometry (forced vital capacity, forced expiratory volume at 1 second, the ratio of forced expiratory volume at 1 second to forced vital capacity) did not correlate with longer endotracheal intubation. Perioperative complications, such as myocardial infarction (p intubation. By multiple regression, priority of operation (p = 0.03), congestive failure (p = 0.02), and previous cardiac operation (p = 0.005) among preoperative risks and bleeding, reduced cardiac output, stroke, coma, and MB fraction of creatine kinase released postoperatively (p endotracheal intubation. Postoperative cardiac function and the occurrence of complications are more significant than preoperative pulmonary function in determining the duration of endotracheal intubation after cardiac operation. Routine spirometry is probably unnecessary for most adult cardiac patients.

  3. Computer-Aided Design of Materials for use under High Temperature Operating Condition

    Energy Technology Data Exchange (ETDEWEB)

    Rajagopal, K. R.; Rao, I. J.

    2010-01-31

    The procedures in place for producing materials in order to optimize their performance with respect to creep characteristics, oxidation resistance, elevation of melting point, thermal and electrical conductivity and other thermal and electrical properties are essentially trial and error experimentation that tend to be tremendously time consuming and expensive. A computational approach has been developed that can replace the trial and error procedures in order that one can efficiently design and engineer materials based on the application in question can lead to enhanced performance of the material, significant decrease in costs and cut down the time necessary to produce such materials. The work has relevance to the design and manufacture of turbine blades operating at high operating temperature, development of armor and missiles heads; corrosion resistant tanks and containers, better conductors of electricity, and the numerous other applications that are envisaged for specially structured nanocrystalline solids. A robust thermodynamic framework is developed within which the computational approach is developed. The procedure takes into account microstructural features such as the dislocation density, lattice mismatch, stacking faults, volume fractions of inclusions, interfacial area, etc. A robust model for single crystal superalloys that takes into account the microstructure of the alloy within the context of a continuum model is developed. Having developed the model, we then implement in a computational scheme using the software ABAQUS/STANDARD. The results of the simulation are compared against experimental data in realistic geometries.

  4. Diagnostics comparing sea surface temperature feedbacks from operational hurricane forecasts to observations

    Directory of Open Access Journals (Sweden)

    Ian D. Lloyd

    2011-11-01

    Full Text Available This paper examines the ability of recent versions of the Geophysical Fluid Dynamics Laboratory Operational Hurricane Forecast Model (GHM to reproduce the observed relationship between hurricane intensity and hurricane-induced Sea Surface Temperature (SST cooling. The analysis was performed by taking a Lagrangian composite of all hurricanes in the North Atlantic from 1998–2009 in observations and 2005–2009 for the GHM. A marked improvement in the intensity-SST relationship for the GHM compared to observations was found between the years 2005 and 2006–2009 due to the introduction of warm-core eddies, a representation of the loop current, and changes to the drag coefficient parameterization for bulk turbulent flux computation. A Conceptual Hurricane Intensity Model illustrates the essential steady-state characteristics of the intensity-SST relationship and is explained by two coupled equations for the atmosphere and ocean. The conceptual model qualitatively matches observations and the 2006–2009 period in the GHM, and presents supporting evidence for the conclusion that weaker upper oceanic thermal stratification in the Gulf of Mexico, caused by the introduction of the loop current and warm core eddies, is crucial to explaining the observed SST-intensity pattern. The diagnostics proposed by the conceptual model offer an independent set of metrics for comparing operational hurricane forecast models to observations.

  5. Temperature fluctuations and the thermodynamic determination of the cooperativity length in glass forming liquids

    Science.gov (United States)

    Chua, Y. Z.; Zorn, R.; Holderer, O.; Schmelzer, J. W. P.; Schick, C.; Donth, E.

    2017-03-01

    The aim of this paper is to decide which of the two possible thermodynamic expressions for the cooperativity length in glass forming liquids is the correct one. In the derivation of these two expressions, the occurrence of temperature fluctuations in the considered nanoscale subsystems is either included or neglected. Consequently, our analysis gives also an answer to the widely discussed problem whether temperature fluctuations have to be generally accounted for in thermodynamics or not. To this end, the characteristic length-scales at equal times and temperatures for propylene glycol were determined independently from AC calorimetry in both the above specified ways and from quasielastic neutron scattering (QENS), and compared. The result shows that the cooperative length determined from QENS coincides most consistently with the cooperativity length determined from AC calorimetry measurements for the case that the effect of temperature fluctuations is incorporated in the description. This conclusion indicates that—accounting for temperature fluctuations—the characteristic length can be derived by thermodynamic considerations from the specific parameters of the liquid at glass transition and that temperature does fluctuate in small systems.

  6. Influence of Fermion Determinant on the Temperature Dependence of Gluon Condensates

    Institute of Scientific and Technical Information of China (English)

    LIU Jue-Ping

    2000-01-01

    The contribution of the fermion determinant to the gluon condensates at a finite temperature is calculated in the framework of the grand partition function for a weak-interacting instanton medium of a disordered phase. It is found that the temperature behavior of both chromomagnetic and chromoelectric gluon condensates depends sensitively on the flavor number. The more the flavors are, the faster the gluon condensates decrease. In the three-flavor case, the gluon condensates would be vanish (or the scale invariance would be restored) approximately at the temperature of 180 MeV.

  7. Experimental method for determination of a suitable temperature range for glasses used in precision molding

    Science.gov (United States)

    Ma, Tao; Chen, Fan; Yu, Jingchi

    2010-10-01

    Viscosity of glass is one of its important technological properties. It is usually adopted as a mark in controlling and evaluating the workability of glass. The viscous features in a glass forming process are strongly relevant to the temperature distribution. Appropriate procedure setting and controlling of temperature is an essential issue for precision glass molding. But the characteristic viscosity of glass is difficult to be observed directly in a practical lens molding. It's not convenient to set up the molding conditions caused by the differences between theoretical data and actual system. The purpose of this experimental study is intended to provide a simple and reliable method for determination of suitable temperature intervals of glasses used in the precision molding fabrication which meets the requirements of process tolerances in the industrial productions. The average glass deforming force and center thickness of molded lens are taken as the two conditions of determination principle for molding temperature ranges. The average force should not less than the minimum value of measurement accuracy and the lens thickness should reach the design target in these temperature ranges. These two conditions are easy to be measured and fit for application in the engineering. The molding temperature ranges of several kinds of glass were obtained in this project. One of them is Schott optical glass P-LASF51 which is selected for evaluating and validating this method. Its suitable molding temperature range is from 590 to 614 . The results of molding experiments demonstrate the method is effective and feasible.

  8. Determination of eruption temperature of Io's lavas using lava tube skylights

    Science.gov (United States)

    Davies, Ashley Gerard; Keszthelyi, Laszlo P.; McEwen, Alfred S.

    2016-11-01

    Determining the eruption temperature of Io's dominant silicate lavas would constrain Io's present interior state and composition. We have examined how eruption temperature can be estimated at lava tube skylights through synthesis of thermal emission from the incandescent lava flowing within the lava tube. Lava tube skylights should be present along Io's long-lived lava flow fields, and are attractive targets because of their temporal stability and the narrow range of near-eruption temperatures revealed through them. We conclude that these skylights are suitable and desirable targets (perhaps the very best targets) for the purposes of constraining eruption temperature, with a 0.9:0.7-μm radiant flux ratio ≤6.3 being diagnostic of ultramafic lava temperatures. Because the target skylights may be small - perhaps only a few m or 10 s of m across - such observations will require a future Io-dedicated mission that will obtain high spatial resolution (lava fountains or roiling lava lakes, where accurate determination of surface temperature distribution requires simultaneous or near-simultaneous (< 0.1 s) observations at different wavelengths, skylight thermal emission data are superior for the purposes of temperature derivation, as emission is stable on much longer time scales (minutes, or longer), so long as viewing geometry does not greatly change during that time.

  9. Exogenous estradiol alters gonadal growth and timing of temperature sex determination in gonads of sea turtle.

    Science.gov (United States)

    Díaz-Hernández, Verónica; Marmolejo-Valencia, Alejandro; Merchant-Larios, Horacio

    2015-12-01

    Temperature sex determining species offer a model for investigating how environmental cues become integrated to the regulation of patterning genes and growth, among bipotential gonads. Manipulation of steroid hormones has revealed the important role of aromatase in the regulation of the estrogen levels involved in temperature-dependent sex determination. Estradiol treatment counteracts the effect of male-promoting temperature, but the resulting ovarian developmental pattern differs from that manifested with the female-promoting temperature. Hypoplastic gonads have been reported among estradiol-treated turtles; however the estradiol effect on gonadal size has not been examined. Here we focused on the sea turtle Lepidochelys olivacea, which develops hypoplastic gonads with estradiol treatment. We studied the effect of estradiol on cell proliferation and on candidate genes involved in ovarian pattern. We found this effect is organ specific, causing a dramatic reduction in gonadal cell proliferation during the temperature-sensitive period. Although the incipient gonads resembled tiny ovaries, remodeling of the medullary cords and down-regulation of testicular factor Sox9 were considerably delayed. Contrastingly, with ovarian promoting temperature as a cue, exogenous estradiol induced the up-regulation of the ovary factor FoxL2, prior to the expression of aromatase. The strong expression of estrogen receptor alpha at the time of treatment suggests that it mediates estradiol effects. Overall results indicate that estradiol levels required for gonadal growth and to establish the female genetic network are delicately regulated by temperature.

  10. DETERMINING UNDISTURBED GROUND TEMPERATURE AS PART OF SHALLOW GEOTHERMAL RESOURCES ASSESSMENT

    Directory of Open Access Journals (Sweden)

    Tomislav Kurevija

    2010-12-01

    Full Text Available The undisturbed ground temperature is one of the key thermogeological parameters for the assessment and utilization of shallow geothermal resources. Geothermal energy is the type of energy which is stored in the ground where solar radiation has no effect. The depth at which the undisturbed ground temperature occurs, independent of seasonal changes in the surface air temperature, is functionally determined by climate parameters and thermogeological properties. In deeper layers, the increase of ground temperature depends solely on geothermal gradient. Determining accurate values of undisturbed ground temperature and depth of occurrence is crucial for the correct sizing of a borehole heat exchanger as part of the ground-source heat pump system, which is considered the most efficient technology for utilising shallow geothermal resources. The purpose of this paper is to define three specific temperature regions, based on the measured ground temperature data collected from the main meteorological stations in Croatia. The three regions are: Northern Croatia, Adriatic region, and the regions of Lika and Gorski Kotar.

  11. Towards an accurate and precise determination of the solid-solid transition temperature of enantiotropic systems

    Energy Technology Data Exchange (ETDEWEB)

    Herman, Christelle, E-mail: christelle.herman@ulb.ac.b [Universite Libre de Bruxelles, Transfers, Interfaces and Processes Department, Chemical Engineering Unit, 50 Avenue Franklin D-Roosevelt, CP 165/67, 1050 Bruxelles (Belgium); Leyssens, Tom [Universite Catholique de Louvain, Institute of Condensed Matter and Nanosciences, 1 Place Louis Pasteur, 1348 Louvain-La-Neuve (Belgium); Vermylen, Valerie [UCB Pharma, 60 Allee de la Recherche, 1070 Braine l' Alleud (Belgium); Halloin, Veronique; Haut, Benoit [Universite Libre de Bruxelles, Transfers, Interfaces and Processes Department, Chemical Engineering Unit, 50 Avenue Franklin D-Roosevelt, CP 165/67, 1050 Bruxelles (Belgium)

    2011-05-15

    Research highlights: We test two methods to obtain the solid-solid transition temperature of Etiracetam system, showing two enantiotropically related polymorphs. The first method, based on a thermodynamic development, is sensitive to the correctness of the data required. The second method is an experimental study of the stability thermal range of each morph. We identify the nature of crystals in suspension at equilibrium through Raman analysis. The solid-solid transition temperature is found equal to 303.65 K {+-} 0.5 K. - Abstract: This paper presents two distinct methods for the determination of the solid-solid transition temperature (T{sub tr}) separating the temperature ranges of stability of two crystallographic forms, hereafter called morphs, of a same substance. The first method, based on thermodynamic calculations, consists in determining T{sub tr} as the temperature at which the Gibbs free energies of the two morphs are equal to each other. For this purpose, some thermodynamic characteristics of both morphs are required, such as the specific heat capacities, the melting temperatures and the melting enthalpies. These are obtained using the Differential Scanning Calorimetry (DSC). In the second method, T{sub tr} is determined directly by an experimental study of the temperature ranges of stability of each morph. The three main originalities of the method developed are (i) to prepare samples composed by an isomassic mixture of crystals of both morphs, (ii) to set them in a thermostated and agitated suspension, and (iii) to use an in situ Raman spectroscopic probe for the determination of the crystallographic form of the crystals in suspension at equilibrium. Both methods are applied to determine the solid-solid transition temperature of the enantiotropic system of Etiracetam, and both of its two crystallographic forms so far identified, named morph I and morph II. The first method is shown to be very sensitive to the experimental data obtained by DSC while

  12. Analysis of the Impact of Decreasing District Heating Supply Temperature on Combined Heat and Power Plant Operation

    Directory of Open Access Journals (Sweden)

    Bolonina Alona

    2014-12-01

    Full Text Available District heating systems are widely used to supply heat to different groups of heat consumers. The district heating system offers great opportunities for combined heat and power production. In this paper decreasing district heating supply temperature is analysed in the context of combined heat and power plant operation. A mathematical model of a CHP plant is developed using both empirical and theoretical equations. The model is used for analysis of modified CHP plant operation modes with reduced district heating supply temperature. Conclusions on the benefits of new operation modes are introduced.

  13. Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors

    Science.gov (United States)

    Chiou, Jin-Chern; Wu, Chin-Cheng; Huang, Yu-Chieh; Chang, Shih-Cheng; Lin, Tse-Mei

    2016-01-01

    This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT) composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 °C, 50 °C, 60 °C, and 70 °C) via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC), polyethylene oxide (PEO), and polyvinylpyrrolidone (PVP). Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM) morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC) testing. PMID:28025507

  14. Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors

    Directory of Open Access Journals (Sweden)

    Jin-Chern Chiou

    2016-12-01

    Full Text Available This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 °C, 50 °C, 60 °C, and 70 °C via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC, polyethylene oxide (PEO, and polyvinylpyrrolidone (PVP. Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC testing.

  15. Climatic, Geographic and Operational Determinants of Trihalomethanes (THMs) in Drinking Water Systems

    Science.gov (United States)

    Valdivia-Garcia, Maria; Weir, Paul; Frogbrook, Zoe; Graham, David W.; Werner, David

    2016-01-01

    Trihalomethanes (THMs) are conditionally carcinogenic compounds formed during chlorine disinfection in water treatment processes around the world. THMs occur especially when source waters are subject to marine influences, high and-or regular precipitation, and elevated levels of organic matter. THMs formation is then rooted in geographic, operational and climatic factors, the relative importance of which can only be derived from large datasets and may change in the future. Ninety three full-scale Scottish water treatment plants (WTPs) were assessed from Jan 2011 to Jan 2013 to identify factors that promote THMs formation. Correlation analysis showed that ambient temperature was the primary THMs formation predictor in potable water (r2 = 0.66, p climatic factors are key to THMs formation. If ambient temperatures increase, THMs control will become more challenging, substantiating concerns about the impact of global warming on water quality. PMID:27762332

  16. Climatic, Geographic and Operational Determinants of Trihalomethanes (THMs) in Drinking Water Systems

    Science.gov (United States)

    Valdivia-Garcia, Maria; Weir, Paul; Frogbrook, Zoe; Graham, David W.; Werner, David

    2016-10-01

    Trihalomethanes (THMs) are conditionally carcinogenic compounds formed during chlorine disinfection in water treatment processes around the world. THMs occur especially when source waters are subject to marine influences, high and-or regular precipitation, and elevated levels of organic matter. THMs formation is then rooted in geographic, operational and climatic factors, the relative importance of which can only be derived from large datasets and may change in the future. Ninety three full-scale Scottish water treatment plants (WTPs) were assessed from Jan 2011 to Jan 2013 to identify factors that promote THMs formation. Correlation analysis showed that ambient temperature was the primary THMs formation predictor in potable water (r2 = 0.66, p real-world dataset confirms both geographic and climatic factors are key to THMs formation. If ambient temperatures increase, THMs control will become more challenging, substantiating concerns about the impact of global warming on water quality.

  17. Determining the first order perturbation of a polyharmonic operator on admissible manifolds

    Science.gov (United States)

    Assylbekov, Yernat M.; Yang, Yang

    2017-01-01

    We consider the inverse boundary value problem for the first order perturbation of the polyharmonic operator L g , X , q, with X being a W 1 , ∞ vector field and q being an L∞ function on compact Riemannian manifolds with boundary which are conformally embedded in a product of the Euclidean line and a simple manifold. We show that the knowledge of the Dirichlet-to-Neumann map determines X and q uniquely. The method is based on the construction of complex geometrical optics solutions using the Carleman estimate for the Laplace-Beltrami operator due to Dos Santos Ferreira, Kenig, Salo and Uhlmann. Notice that the corresponding uniqueness result does not hold for the first order perturbation of the Laplace-Beltrami operator.

  18. Determining soil moisture by assimilating soil temperature measurements using the Ensemble Kalman Filter

    Science.gov (United States)

    Dong, Jianzhi; Steele-Dunne, Susan C.; Ochsner, Tyson E.; van de Giesen, Nick

    2015-12-01

    This study investigates the potential to estimate the vertical profile of soil moisture by assimilating temperature observations at a limited number of depths into a coupled heat and moisture transport model (Hydrus-1D). The method is developed with a view to assimilating temperature data from distributed temperature sensing (DTS) to estimate soil moisture at high resolution over large areas. The correlation between temperature and soil moisture in the shallow soil (top ∼ 50 cm) ensures that soil moisture can be estimated using just soil temperature observations. Synthetic tests across a range of soil textures show that with data assimilation both modeled temperature and the moisture profile are improved considerably compared to the ensemble open loop model simulations. In addition, employing data assimilation provides a means to quantitatively account for different sources of uncertainty. This is particularly relevant in the context of DTS given the influence of spatial variability in soil texture and its impact on estimation error. The data assimilation approach could also be used to determine, the number of temperature observations required and the depths at which they should be made. Results suggest that temperature observed at two depths is typically sufficient to estimate soil moisture using this approach. The root mean square error (RMSE) in soil moisture was reduced by up to 75% in the top 20 cm. Furthermore, this approach solves many of the challenges identified in the application of an inversion approach to estimate soil moisture from DTS.

  19. Generation of high resolution sea surface temperature using multi-satellite data for operational oceanography

    Institute of Scientific and Technical Information of China (English)

    YANG Chan-Su; KIM Sun-Hwa; OUCHI Kazuo; BACK Ji-Hun

    2015-01-01

    In the present article, we introduce a high resolution sea surface temperature (SST) product generated daily by Korea Institute of Ocean Science and Technology (KIOST). The SST product is comprised of four sets of data including eight-hour and daily average SST data of 1 km resolution, and is based on the four infrared (IR) satellite SST data acquired by advanced very high resolution radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS), Multifunctional Transport Satellites-2 (MTSAT-2) Imager and Meteorological Imager (MI), two microwave radiometer SSTs acquired by Advanced Microwave Scanning Radiometer 2 (AMSR2), and WindSAT within-situ temperature data. These input satellite andin-situ SST data are merged by using the optimal interpolation (OI) algorithm. The root-mean-square-errors (RMSEs) of satellite andin-situ data are used as a weighting value in the OI algorithm. As a pilot product, four SST data sets were generated daily from January to December 2013. In the comparison between the SSTs measured by moored buoys and the daily mean KIOST SSTs, the estimated RMSE was 0.71°C and the bias value was –0.08°C. The largest RMSE and bias were 0.86 and –0.26°C respectively, observed at a buoy site in the boundary region of warm and cold waters with increased physical variability in the Sea of Japan/East Sea. Other site near the coasts shows a lower RMSE value of 0.60°C than those at the open waters. To investigate the spatial distributions of SST, the Group for High Resolution Sea Surface Temperature (GHRSST) product was used in the comparison of temperature gradients, and it was shown that the KIOST SST product represents well the water mass structures around the Korean Peninsula. The KIOST SST product generated from both satellite and buoy data is expected to make substantial contribution to the Korea Operational Oceanographic System (KOOS) as an input parameter for data assimilation.

  20. An operational method for the disaggregation of land surface temperature to estimate actual evapotranspiration in the arid region of Chile

    Science.gov (United States)

    Olivera-Guerra, L.; Mattar, C.; Merlin, O.; Durán-Alarcón, C.; Santamaría-Artigas, A.; Fuster, R.

    2017-06-01

    Monitoring evapotranspiration in arid and semi-arid environments plays a key role in water irrigation scheduling for water use efficiency. This work presents an operational method for evapotranspiration retrievals based on disaggregated Land Surface Temperature (LST). The retrieved LSTs from Landsat-8 and MODIS data were merged in order to provide an 8-day composite LST product at 100 × 100 m resolution. The method was tested in the arid region of Copiapó, Chile using data from years 2013-2014 and validated using data from years 2015-2016. In-situ measurements from agrometeorological stations such as air temperature and potential evapotranspiration (ET0) estimated at the location were used in the ET estimation method. The disaggregation method was developed by taking into account (1) the spatial relationship between Landsat-8 and MODIS LST, (2) the spatial relationship between LST and the Normalized Difference Vegetation Index (NDVI) at high spatial resolution (Landsat-8), and (3) the temporal variations along the year of both relationships aforementioned. The comparison between disaggregated LST at 100 m resolution and in situ LST measurements presents a coefficient of determination (r2), in average, equal to 0.70 and a RMSE equal to 3.6 K. The disaggregated LST was used in an operational model to estimate the actual evapotranspiration (ETa). The ETa shows good results in terms of seasonal variations and in comparison to the evapotranspiration estimated by using crop coefficients (kc). The comparison between remotely sensed and in situ ETa presents an overall r2 close to 0.67 and a RMSE equal to 0.6 mm day-1 for both crops. These results are important for further improvements in water use sustainability in the Copiapó valley, which is currently affected by high water demand.

  1. Determining Capital Cost in Wastewater Treatment Installations Operating Under Inflow Characteristics Uncertainty

    Science.gov (United States)

    Batzias, D. F.; Pollalis, Y. A.

    2007-12-01

    This work deals with the determination of capital cost in wastewater treatment installations operating under inflow characteristics uncertainty. For this purpose, a methodological framework, under the form of an algorithmic procedure, has been designed/developed and successfully implemented in two cases of biological processing under steady state conditions. The results obtained are in satisfactory approximation with industrial data. Moreover, mathematical formulae have been derived for determining capital cost when processing takes place under unsteady state conditions; in this case, numerical approximation is necessary, since the expressions obtained have not analytic solution. Last, the influence of certain technical parameters on minimum capital cost is discussed.

  2. DETERMINATION ANALYSIS OF TEMPERATURE REGIMES, FUNCTIONAL CHARACTERISTICS AND SLIDING CURVES OF A HYDRODYNAMIC CLUTCH

    Directory of Open Access Journals (Sweden)

    Božidar V Krstić

    2010-01-01

    Full Text Available Analysis of output quality of power transmitters is possible in position when characteristics are determined earlier. This is the reason why we focused on determination of these characteristics for a concrete power hydro-transmitter. This means that the investigation task primarily consisted of determination of functional characteristics, defining of the sliding curves and temperature regimes of a concrete hydrodynamic clutch. Results of velocity and pressure field investigations in the working space of this clutch, obtained by use of the same test setup, are the basis for determination and analysis of the functional characteristics, sliding curves and temperature regimes. In this work we also analyzed function of the hydrodynamic transmitter in assembly with an internal combustion engine, as well as a process of acceleration and deceleration of a vehicle with this assembly in it.

  3. Derivation and evaluation of land surface temperature from the geostationary operational environmental satellite series

    Science.gov (United States)

    Fang, Li

    The Geostationary Operational Environmental Satellites (GOES) have been continuously monitoring the earth surface since 1970, providing valuable and intensive data from a very broad range of wavelengths, day and night. The National Oceanic and Atmospheric Administration's (NOAA's) National Environmental Satellite, Data, and Information Service (NESDIS) is currently operating GOES-15 and GOES-13. The design of the GOES series is now heading to the 4 th generation. GOES-R, as a representative of the new generation of the GOES series, is scheduled to be launched in 2015 with higher spatial and temporal resolution images and full-time soundings. These frequent observations provided by GOES Image make them attractive for deriving information on the diurnal land surface temperature (LST) cycle and diurnal temperature range (DTR). These parameters are of great value for research on the Earth's diurnal variability and climate change. Accurate derivation of satellite-based LSTs from thermal infrared data has long been an interesting and challenging research area. To better support the research on climate change, the generation of consistent GOES LST products for both GOES-East and GOES-West from operational dataset as well as historical archive is in great demand. The derivation of GOES LST products and the evaluation of proposed retrieval methods are two major objectives of this study. Literature relevant to satellite-based LST retrieval techniques was reviewed. Specifically, the evolution of two LST algorithm families and LST retrieval methods for geostationary satellites were summarized in this dissertation. Literature relevant to the evaluation of satellite-based LSTs was also reviewed. All the existing methods are a valuable reference to develop the GOES LST product. The primary objective of this dissertation is the development of models for deriving consistent GOES LSTs with high spatial and high temporal coverage. Proper LST retrieval algorithms were studied

  4. Lead iodide X-ray and gamma-ray spectrometers for room and high temperature operation

    Energy Technology Data Exchange (ETDEWEB)

    Hermon, H.; James, R.B.; Cross, E. [and others

    1997-02-01

    In this study, we report on the results of the investigation of lead iodide material properties. The effectiveness of zone refining purification methods on the material purity is determined by ICP-MS and ICP-OES and correlated to the electrical and physical material properties. We show that this zone refining method is very efficient in removing impurities from lead iodide and we also determine the segregation coefficient for some of these impurities. Triple axis x- ray diffraction (TAD) analysis has been used to determine the crystalline perfection of the lead iodide after applying various cutting, etching, and fabrication methods. The soft lead iodide crystal was found to be damaged when cleaved by a razor blade, but by using a diamond wheel saw, followed by etching, the crystallinity of the material was improved, as observed by TAD. Low temperature photoluminescence also indicates an improvement in the material properties of the purified lead iodide. Electrical properties of lead iodide such as carrier mobility, were calculated based on carrier- phonon scattering. The results for the electrical properties were in good agreement with the experimental data.

  5. Progress towards the determination of thermodynamic temperature with ultra-low uncertainty.

    Science.gov (United States)

    Gavioso, Roberto M; Ripa, Daniele Madonna; Steur, Peter P M; Gaiser, Christof; Zandt, Thorsten; Fellmuth, Bernd; de Podesta, Michael; Underwood, Robin; Sutton, Gavin; Pitre, Laurent; Sparasci, Fernando; Risegari, Lara; Gianfrani, Livio; Castrillo, Antonio; Machin, Graham

    2016-03-28

    Previous research effort towards the determination of the Boltzmann constant has significantly improved the supporting theory and the experimental practice of several primary thermometry methods based on the measurement of a thermodynamic property of a macroscopic system at the temperature of the triple point of water. Presently, experiments are under way to demonstrate their accuracy in the determination of the thermodynamic temperature T over an extended range spanning the interval between a few kelvin and the copper freezing point (1358 K). We discuss how these activities will improve the link between thermodynamic temperature and the temperature as measured using the International Temperature Scale of 1990 (ITS-90) and report some preliminary results obtained by dielectric constant gas thermometry and acoustic gas thermometry. We also provide information on the status of other primary methods, such as Doppler broadening thermometry, Johnson noise thermometry and refractive index gas thermometry. Finally, we briefly consider the implications of these advancements for the dissemination of calibrated temperature standards.

  6. Development of ex vivo model for determining temperature distribution in tumor tissue during photothermal therapy

    Science.gov (United States)

    Liu, Shaojie; Doughty, Austin; Mesiya, Sana; Pettitt, Alex; Zhou, Feifan; Chen, Wei R.

    2017-02-01

    Temperature distribution in tissue is a crucial factor in determining the outcome of photothermal therapy in cancer treatment. In order to investigate the temperature distribution in tumor tissue during laser irradiation, we developed a novel ex vivo device to simulate the photothermal therapy on tumors. A 35°C, a thermostatic incubator was used to provide a simulation environment for body temperature of live animals. Different biological tissues (chicken breast and bovine liver) were buried inside a tissue-simulating gel and considered as tumor tissues. An 805-nm laser was used to irradiate the target tissue. A fiber with an interstitial cylindrical diffuser (10 mm) was directly inserted in the center of the tissue, and the needle probes of a thermocouple were inserted into the tissue paralleling the laser fiber at different distances to measure the temperature distribution. All of the procedures were performed in the incubator. Based on the results of this study, the temperature distribution in bovine liver is similar to that of tumor tissue under photothermal therapy with the same doses. Therefore, the developed model using bovine liver for determining temperature distribution can be used during interstitial photothermal therapy.

  7. Temperature Effects of Point Sources, Riparian Shading, and Dam Operations on the Willamette River, Oregon

    Science.gov (United States)

    Rounds, Stewart A.

    2007-01-01

    Water temperature is an important factor influencing the migration, rearing, and spawning of several important fish species in rivers of the Pacific Northwest. To protect these fish populations and to fulfill its responsibilities under the Federal Clean Water Act, the Oregon Department of Environmental Quality set a water temperature Total Maximum Daily Load (TMDL) in 2006 for the Willamette River and the lower reaches of its largest tributaries in northwestern Oregon. As a result, the thermal discharges of the largest point sources of heat to the Willamette River now are limited at certain times of the year, riparian vegetation has been targeted for restoration, and upstream dams are recognized as important influences on downstream temperatures. Many of the prescribed point-source heat-load allocations are sufficiently restrictive that management agencies may need to expend considerable resources to meet those allocations. Trading heat allocations among point-source dischargers may be a more economical and efficient means of meeting the cumulative point-source temperature limits set by the TMDL. The cumulative nature of these limits, however, precludes simple one-to-one trades of heat from one point source to another; a more detailed spatial analysis is needed. In this investigation, the flow and temperature models that formed the basis of the Willamette temperature TMDL were used to determine a spatially indexed 'heating signature' for each of the modeled point sources, and those signatures then were combined into a user-friendly, spreadsheet-based screening tool. The Willamette River Point-Source Heat-Trading Tool allows the user to increase or decrease the heating signature of each source and thereby evaluate the effects of a wide range of potential point-source heat trades. The predictions of the Trading Tool were verified by running the Willamette flow and temperature models under four different trading scenarios, and the predictions typically were accurate

  8. OPERATIONS THROUGHPUT AS A DETERMINANT OF GOLDEN-HOUR IN MASS-GATHERING MEDICINE

    Directory of Open Access Journals (Sweden)

    I. D. Khan

    2017-07-01

    Full Text Available BACKGROUND Golden-hour, a time-tested concept for trauma-care, involves a systems approach encompassing healthcare, logistics, geographical, environmental and temporal variables. Golden-hour paradigm in mass-gathering-medicine such as the Hajj-pilgrimage entwines along healthcare availability, accessibility, efficiency and interoperability; expanding from the patient-centric to public-health centric approach. The realm of mass-gathering-medicine invokes an opportunity for incorporating operations-throughput as a determinant of golden-hour for overall capacity-building and interoperability. METHODS Golden-hour was evaluated during the Indian-Medical-Mission operations for Hajj-2016; which established, operated and coordinated a strategic network of round-the-clock medical operations. Throughput was evaluated as deliverables/time, against established Standard-Operating-Procedures for various clinical, investigation, drug-dispensing and patient-transfer algorithms. Patient encounter-time, waiting-time, turnaround-time were assessed throughout echeloned healthcare under a patient-centric healthcare-delivery model. Dynamic evaluation was carried out to cater for variation and heterogeneity. RESULTS Massive surge of 3,94,013 patients comprising 2,25,103 males (57.1% and 1,68,910 females (42.9% overwhelmed the throughput capacities of outpatient attendance, pharmacy, laboratory, imaging, ambulance, referrals and documentation. There was delay in attendance, suspicion, diagnosis and isolation of patients with communicable infections. The situational-analysis of operations-throughput highlights wasted turnaround-time due to mobilization of medical-team, diverting critical healthcare resources away from emergency situations. CONCLUSION Time being a crucial factor in the complexity of medical-care, operations-throughput remains an important determinant towards interoperability of bottlenecks, thereby being a determinant of golden-hour in mass

  9. Structure determination of an integral membrane protein at room temperature from crystals in situ

    Energy Technology Data Exchange (ETDEWEB)

    Axford, Danny [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Foadi, James [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Hu, Nien-Jen; Choudhury, Hassanul Ghani [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Iwata, So [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Kyoto University, Kyoto 606-8501 (Japan); Beis, Konstantinos [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Evans, Gwyndaf, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Alguel, Yilmaz, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom)

    2015-05-14

    The X-ray structure determination of an integral membrane protein using synchrotron diffraction data measured in situ at room temperature is demonstrated. The structure determination of an integral membrane protein using synchrotron X-ray diffraction data collected at room temperature directly in vapour-diffusion crystallization plates (in situ) is demonstrated. Exposing the crystals in situ eliminates manual sample handling and, since it is performed at room temperature, removes the complication of cryoprotection and potential structural anomalies induced by sample cryocooling. Essential to the method is the ability to limit radiation damage by recording a small amount of data per sample from many samples and subsequently assembling the resulting data sets using specialized software. The validity of this procedure is established by the structure determination of Haemophilus influenza TehA at 2.3 Å resolution. The method presented offers an effective protocol for the fast and efficient determination of membrane-protein structures at room temperature using third-generation synchrotron beamlines.

  10. Unified approach for determining the enthalpic fictive temperature of glasses with arbitrary thermal history

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Potuzak, M.; Mauro, J. C.;

    2011-01-01

    We propose a unified routine to determine the enthalpic fictive temperature of a glass with arbitrary thermal history under isobaric conditions. The technique is validated both experimentally and numerically using a novel approach for modeling of glass relaxation behavior. The technique is applic...

  11. Determination of the Arrhenius Activation Energy Using a Temperature-Programmed Flow Reactor.

    Science.gov (United States)

    Chan, Kit-ha C.; Tse, R. S.

    1984-01-01

    Describes a novel method for the determination of the Arrhenius activation energy, without prejudging the validity of the Arrhenius equation or the concept of activation energy. The method involves use of a temperature-programed flow reactor connected to a concentration detector. (JN)

  12. Computer program determines thermal environment and temperature history of lunar orbiting space vehicles

    Science.gov (United States)

    Head, D. E.; Mitchell, K. L.

    1967-01-01

    Program computes the thermal environment of a spacecraft in a lunar orbit. The quantities determined include the incident flux /solar and lunar emitted radiation/, total radiation absorbed by a surface, and the resulting surface temperature as a function of time and orbital position.

  13. Determination of solidus and liquidus temperatures for bearing steel by thermal analysis methods

    Directory of Open Access Journals (Sweden)

    K. Gryc

    2017-01-01

    Full Text Available The first part of presented paper is devoted to comparison of solidus and liquidus temperatures determined by two methods of thermal analysis for one real steel grade 100CrMo7. Two modern devices for high-temperature analysis were used. The direct thermal analysis method was used during an experiments realised on large samples (22 g at NETZSCH JUPITER device. Small bearing steel samples (up to 210 mg were studied by differential thermal analysis method at Setaram SETSYS 18TM.The robustness of both used thermo-analytical methods was documented. Measured results were compared with liquidus and solidus temperatures used in industry and calculated by specialized IDS and ThermoCalc software. Measured temperatures differ from the theoretically calculated by tens for liquidus to more than 100 °C for solidus.

  14. An inverse radiation model for optical determination of temperature and species concentration: Development and validation

    DEFF Research Database (Denmark)

    Ren, Tao; Modest, Michael F.; Fateev, Alexander

    2015-01-01

    In this study, we present an inverse calculation model based on the Levenberg-Marquardt optimization method to reconstruct temperature and species concentration from measured line-of-sight spectral transmissivity data for homogeneous gaseous media. The high temperature gas property database HITEMP...... 2010 (Rothman et al. (2010) [1]), which contains line-by-line (LBL) information for several combustion gas species, such as CO2 and H2O, was used to predict gas spectral transmissivities. The model was validated by retrieving temperatures and species concentrations from experimental CO2 and H2O...... transmissivity measurements. Optimal wavenumber ranges for CO2 and H2O transmissivity measured across a wide range of temperatures and concentrations were determined according to the performance of inverse calculations. Results indicate that the inverse radiation model shows good feasibility for measurements...

  15. A Parameter Identification Method to Determine Salinity of Sea Ice Using Temperature and Thickness Observations

    Science.gov (United States)

    Lv, Wei; Li, Xiaojiao; Feng, Enmin

    2014-02-01

    This study is intended to provide a parameter identification method to determine the salinity of sea ice using temperature and thickness measurements. This method is particularly effective when field data are sparse and unsatisfactory due to the difficulties associated with fieldwork, especially during the polar winter. The main idea of the method is described. The salinity profile is calculated by the temperature and thickness observations, which were measured at Nella Fjord around Zhongshan Station, Antarctica during the polar night time by the 22nd Chinese Antarctic Research Expedition. Another simulation for temperature profiles during a different measurement period is performed. Results show that better simulations of the salinity and temperature distributions are possible with the estimated parameters than with Eicken's and THESCI's methods. This method will help people to understand the salinity evolution of sea ice more thoroughly.

  16. Determination of the EOS maragingsteel MS1 material resistance at low temperatures

    Directory of Open Access Journals (Sweden)

    J. Dobránsky

    2016-07-01

    Full Text Available This article deals with determination of the EOS MaragingSteel MS1 material resistance at different low temperatures. Material resistance was evaluated in two types of standardized specimens. The impact energy at the specimens tested at 10 °C, values for the specimens with no notch were compared to the V - notch specimens, higher by approximately one - third. When the temperature dropped to 0 °C, the values of the impact energy slightly decreased as well. It therefore follows that lower temperatures result in decrease in the values of the impact strength. This experiment provided us with the opportunity to find out whether the decrease in temperature impacts the resistance of the tested material.

  17. [Determination of the gelatinization temperature of starches via thermoanalytical and rheological methods].

    Science.gov (United States)

    Szepes, Aniko; Fehér, András; Eros, István; Szabóné, Révész Piroska

    2007-01-01

    This work provides a short review concerning the measuring techniques frequently applied to characterize the gelatinization behaviour of starches. The aim of the experiments was to determine the gelatinization temperatures of maize (A-type) and potato (B-type) starches via isothermal microcalorimetry and rheological methods (rotational viscosimetry and dynamic oscillatory testing). A significant difference was observed between the gelatinization temperatures of the aqueous starch suspensions, which can be attributed to the structural differences between A-type and B-type starches. Comparison of the applied measuring methods revealed a close correlation between the experimental data obtained by isothermal microcalorimetry and oscillatory testing, while rotational viscosimetry overestimated the gelatinization temperature. Additionally dynamic oscillatory tests provided valuable information not only on the gelatinization point, but also on the pasting temperature of the starch suspensions.

  18. A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle.

    Science.gov (United States)

    Schroeder, Anthony L; Metzger, Kelsey J; Miller, Alexandra; Rhen, Turk

    2016-05-01

    Temperature-dependent sex determination (TSD) was described nearly 50 years ago. Researchers have since identified many genes that display differential expression at male- vs. female-producing temperatures. Yet, it is unclear whether these genes (1) are involved in sex determination per se, (2) are downstream effectors involved in differentiation of ovaries and testes, or (3) are thermo-sensitive but unrelated to gonad development. Here we present multiple lines of evidence linking CIRBP to sex determination in the snapping turtle, Chelydra serpentina We demonstrate significant associations between a single nucleotide polymorphism (SNP) (c63A > C) in CIRBP, transcript levels in embryonic gonads during specification of gonad fate, and sex in hatchlings from a thermal regime that produces mixed sex ratios. The A allele was induced in embryos exposed to a female-producing temperature, while expression of the C allele did not differ between female- and male-producing temperatures. In accord with this pattern of temperature-dependent, allele-specific expression, AA homozygotes were more likely to develop ovaries than AC heterozygotes, which, in turn, were more likely to develop ovaries than CC homozygotes. Multiple regression using SNPs in CIRBP and adjacent loci suggests that c63A > C may be the causal variant or closely linked to it. Differences in CIRBP allele frequencies among turtles from northern Minnesota, southern Minnesota, and Texas reflect small and large-scale latitudinal differences in TSD pattern. Finally, analysis of CIRBP protein localization reveals that CIRBP is in a position to mediate temperature effects on the developing gonads. Together, these studies strongly suggest that CIRBP is involved in determining the fate of the bipotential gonad.

  19. Embryonic origin of mate choice in a lizard with temperature-dependent sex determination.

    Science.gov (United States)

    Putz, Oliver; Crews, David

    2006-01-01

    Individual differences in the adult sexual behavior of vertebrates are rooted in the fetal environment. In the leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), hatchling sex ratios differ between incubation temperatures, as does sexuality in same-sex animals. This variation can primarily be ascribed to the temperature having direct organizing actions on the brain. Here we demonstrate that embryonic temperature can affect adult mate choice in the leopard gecko. Given the simultaneous choice between two females from different incubation temperatures (30.0 and 34.0 degrees C), males from one incubation temperature (30.0 degrees C) preferred the female from 34.0 degrees C, while males from another incubation temperature (32.5 degrees C) preferred the female from 30.0 degrees C. We suggest that this difference in mate choice is due to an environmental influence on brain development leading to differential perception of opposite-sex individuals. This previously unrecognized modulator of adult mate choice lends further support to the view that mate choice is best understood in the context of an individual's entire life-history. Thus, sexual selection results from a combination of the female's as well as the male's life history. Female attractiveness and male choice therefore are complementary.

  20. Overcoming dormancy and determining optimal temperature for slender serradella seed germination

    Directory of Open Access Journals (Sweden)

    Rodrigo Ramos Lopes

    2015-12-01

    Full Text Available ABSTRACT The objective of this study was to identify the most efficient method for overcoming coat-imposed dormancy and determine the optimal germination temperature for Ornithopus pinnatus seeds. Treatments to overcome dormancy were: intact seeds; immersion in hot water at 60 ºC, followed by soaking in the same water (unheated/24 h; immersion in hot water at 90 ºC, followed by soaking in the same water (unheated/24 h; mechanical scarification; chemical scarification, H2SO4/5 min; and chemical scarification, H2SO4/10 min. Percentages were calculated for germinated, abnormal, dormant, and dead seeds. Optimal germination temperatures were calculated using eight constant temperatures (0, 5, 10, 15, 20, 25, 30, and 35 °C, with 8 h of light and 16 h of darkness. Germination rate, frequency, and synchronization index of germination were used as parameters to establish optimum temperature for germination. A completely randomized experimental design was used, with twelve repetitions of 100 seeds per treatment. Data obtained were subjected to analysis of variance and Tukey's test at a 5% significance level. O. pinnatus seeds exhibit dormancy caused by the seed coat's impermeability to water. Mechanical scarification was efficient in promoting seed germination. The species is stenothermal, meaning it cannot tolerate significant temperature variations. The germination rate of seeds was linearly dependent on temperature. Synchronization of the germination process is greater in the optimum temperature range, established between 15 and 20 °C.

  1. A Model for the Determination of Diffusion Capacity Under Non-Standard Temperature and Pressure Conditions

    Directory of Open Access Journals (Sweden)

    Eitzinger Bernhard

    2014-07-01

    Full Text Available The diffusion capacity of cigarette paper has been reported to be an important parameter in relation to the self-extinguishment of cigarettes and also in relation to carbon monoxide yields. Although the diffusion capacity is routinely measured and instruments for this measurement have been available for several years, differences between measured values obtained on the same paper sample but on different instruments or in different laboratories may be substantial and may make it difficult to use these values, for example, as a basis for paper specifications. Among several reasons, deviations of temperature and pressure from standard conditions, especially within the measurement chamber of the instrument, may contribute to the high variation in diffusion capacity data. Deviations of temperature and pressure will have an influence on the gas flow rates, the diffusion processes inside the measurement chamber and consequently the measured CO2 concentration. Generally, the diffusion capacity is determined from a mathematical model, which describes the diffusion processes inside the measurement chamber. Such models provide the CO2 concentration in the outflow gas for a given diffusion capacity. For practical applications the inverse model is needed, that is, the diffusion capacity shall be determined from a measured CO2 concentration. Often such an inverse model is approximated by a polynomial, which, however, is only valid for standard temperature and pressure. It is shown that relative approximation errors from such polynomials, even without temperature and pressure deviations, cannot always be neglected and it is proposed to eliminate such errors by direct inversion of the model with a comparably simple iterative method. A model which includes temperature and pressure effects is described and the effects of temperature and pressure deviations on the diffusion capacity are theoretically estimated by comparing the output of a model with and without

  2. A new sensor for ammonia based on cyanidin-sensitized titanium dioxide film operating at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Xiao-wei, Huang [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Xiao-bo, Zou, E-mail: zou_xiaobo@ujs.edu.cn [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Key Laboratory of Modern Agricultural Equipment and Technology, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Ji-yong, Shi; Jie-wen, Zhao; Yanxiao, Li [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Limin, Hao; Jianchun, Zhang [The Research Center of China Hemp Materials, Beijing (China)

    2013-07-17

    Graphical abstract: -- Highlights: •TiO{sub 2} was prepared by sol–gel method film and then functionalized with the cyanidin dye. •The morphology and the absorption spectra of films were examined. •The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. •The low humidity could promote the sensitivity of the sensors. -- Abstract: Design and fabrication of an ammonia sensor operating at room temperature based on pigment-sensitized TiO{sub 2} films was described. TiO{sub 2} was prepared by sol–gel method and deposited on glass slides containing gold electrodes. Then, the film immersed in a 2.5 × 10{sup −4} M ethanol solution of cyanidin to absorb the pigment. The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. The relative change resistance of the films at a potential difference of 1.5 V is determined when the films are exposed to atmospheres containing ammonia vapors with concentrations over the range 10–50 ppm. The relative change resistance, S, of the films increased almost linearly with increasing concentrations of ammonia (r = 0.92). The response time to increasing concentrations of the ammonia is about 180–220 s, and the corresponding values for decreasing concentrations 240–270 s. At low humidity, ammonia could be ionized by the cyanidin on the TiO{sub 2} film and thereby decrease in the proton concentration at the surface. Consequently, more positively charged holes at the surface of the TiO{sub 2} have to be extracted to neutralize the adsorbed cyanidin and water film. The resistance response to ammonia of the sensors was nearly independent on temperature from 10 to 50 °C. These results are not actually as good as those reported in the literature, but this preliminary work proposes simpler and cheaper processes to realize NH{sub 3} sensor for room temperature applications.

  3. Dimorphic DNA methylation during temperature-dependent sex determination in the sea turtle Lepidochelys olivacea.

    Science.gov (United States)

    Venegas, Daniela; Marmolejo-Valencia, Alejandro; Valdes-Quezada, Christian; Govenzensky, Tzipe; Recillas-Targa, Félix; Merchant-Larios, Horacio

    2016-09-15

    Sex determination in vertebrates depends on the expression of a conserved network of genes. Sea turtles such as Lepidochelys olivacea have temperature-dependent sex determination. The present work analyses some of the epigenetic processes involved in this. We describe sexual dimorphism in global DNA methylation patterns between ovaries and testes of L. olivacea and show that the differences may arise from a combination of DNA methylation and demethylation events that occur during sex determination. Irrespective of incubation temperature, 5-hydroxymethylcytosine was abundant in the bipotential gonad; however, following sex determination, this modification was no longer found in pre-Sertoli cells in the testes. These changes correlate with the establishment of the sexually dimorphic DNA methylation patterns, down regulation of Sox9 gene expression in ovaries and irreversible gonadal commitment towards a male or female differentiation pathway. Thus, DNA methylation changes may be necessary for the stabilization of the gene expression networks that drive the differentiation of the bipotential gonad to form either an ovary or a testis in L. olivacea and probably among other species that manifest temperature-dependent sex determination.

  4. Practical Considerations for Determination of Glass Transition Temperature of a Maximally Freeze Concentrated Solution.

    Science.gov (United States)

    Pansare, Swapnil K; Patel, Sajal Manubhai

    2016-08-01

    Glass transition temperature is a unique thermal characteristic of amorphous systems and is associated with changes in physical properties such as heat capacity, viscosity, electrical resistance, and molecular mobility. Glass transition temperature for amorphous solids is referred as (T g), whereas for maximally freeze concentrated solution, the notation is (T g'). This article is focused on the factors affecting determination of T g' for application to lyophilization process design and frozen storage stability. Also, this review provides a perspective on use of various types of solutes in protein formulation and their effect on T g'. Although various analytical techniques are used for determination of T g' based on the changes in physical properties associated with glass transition, the differential scanning calorimetry (DSC) is the most commonly used technique. In this article, an overview of DSC technique is provided along with brief discussion on the alternate analytical techniques for T g' determination. Additionally, challenges associated with T g' determination, using DSC for protein formulations, are discussed. The purpose of this review is to provide a practical industry perspective on determination of T g' for protein formulations as it relates to design and development of lyophilization process and/or for frozen storage; however, a comprehensive review of glass transition temperature (T g, T g'), in general, is outside the scope of this work.

  5. Photodetector development at Fraunhofer IAF: From LWIR to SWIR operating from cryogenic close to room temperature

    Science.gov (United States)

    Daumer, V.; Gramich, V.; Müller, R.; Schmidt, J.; Rutz, F.; Stadelmann, T.; Wörl, A.; Rehm, R.

    2017-02-01

    Photodetectors in the non-visible region of the electromagnetic spectrum are essential for security, defense and space science as well as industrial and scientific applications. The research activities at Fraunhofer IAF cover a broad range in the infrared (IR) regime. Whereas short-wavelength IR (SWIR, <1.7 μm) detectors are realized by InGaAs/InP structures, InAs/GaSb type-II superlattice (T2SL) infrared detectors are developed for the spectral bands from mid- (MWIR, 3-5 μm) to long-wavelength IR (LWIR, 8-12 μm). We report on the extension of the superlattice empirical pseudopotential method (SEPM) to 300 K for the design of LWIR heterostructures for operation near room temperature. Recently, we have also adapted heterostructure concepts to our well established bi-spectral T2SL MWIR detector resulting in a dark current density below 2 × 10-9 A/cm2 for a cut-off wavelength close to 5 μm. Finally, we present first results obtained with a gated viewing system based on our InGaAs/InAlAs/InP avalanche photodiode arrays.

  6. Variation of ADM1 by using temperature-phased anaerobic digestion (TPAD) operation.

    Science.gov (United States)

    Lee, Myung-Yeol; Suh, Chang-Won; Ahn, Yong-Tae; Shin, Hang-Sik

    2009-06-01

    The objective of the study was to examine the application of the Anaerobic Digestion Model No. 1 (ADM1) developed by the IWA task group for mathematical modelling of anaerobic process. Lab-scale temperature-phased anaerobic digestion (TPAD) process were operated continuously, and were fed with co-substrate composed of dog food and flour. The model platform implemented in the simulation was a derivative of the ADM1. Sensitivity analysis showed that k(m.process) (maximum specific uptake rate) and K(S.process) (half saturation value) had high sensitivities to model components. Important parameters including maximum uptake rate for propionate utilisers (k(m.pro)) and half saturation constant for acetate utilisers (K(S.ac)) in the thermophilic digester and maximum uptake rate for acetate utilisers (k(m.ac)) in the mesophilic digester were estimated using iterative methods, which optimized the parameters with experimental results. Simulation with estimated parameters showed good agreement with experimental results in the case of methane production, uptake of acetate, soluble chemical oxygen demand (SCOD) and total chemical oxygen demand (TCOD). Under these conditions, the model predicted reasonably well the dynamic behavior of the TPAD process for verifying the model.

  7. Simulation Study of Effects, Operating Temperature and Layer Thickness on Thin Film CIGS Solar Cell Performance

    Directory of Open Access Journals (Sweden)

    A.D. Pogrebnjak

    2011-01-01

    Full Text Available SCAPS- program is designed basically for the simulation and studying the properties of photonic devices. We explored the important controllable design parameters affecting the performance of the hetero junction solar cells, as operating temperature that we noticed increasing in J-V characteristics by increasing T, the effect of thickness of each layer on the performance of the cell was studied, an increasing of J-V characteristics with increasing p-layer , In the numerical example, 3 μm absorber layer and CdS layer 0.05 μm, ZnO layer 0.1 μm, works the best for given doping density, if we change the optimum value , the efficiency can reach to 17.72 % with FF 83.88 %, Voc = 0.725 Volt, Jsc = 29.07 mA/cm2 at 300 K, in this case, we have come out the optimum parameters to achieve the best performance of this type of cell, and then to made comparison with practical CIGS cell.

  8. High Operating Temperature Midwave Quantum Dot Barrier Infrared Detector (QD-BIRD)

    Science.gov (United States)

    Ting, David Z.; Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Mumolo, Jason M.; Gunapala, Sarath D.

    2012-01-01

    The nBn or XBn barrier infrared detector has the advantage of reduced dark current resulting from suppressed Shockley-Read-Hall (SRH) recombination and surface leakage. High performance detectors and focal plane arrays (FPAs) based on InAsSb absorber lattice matched to GaSb substrate, with a matching AlAsSb unipolar electron barrier, have been demonstrated. The band gap of lattice-matched InAsSb yields a detector cutoff wavelength of approximately 4.2 ??m when operating at 150K. We report results on extending the cutoff wavelength of midwave barrier infrared detectors by incorporating self-assembled InSb quantum dots into the active area of the detector. Using this approach, we were able to extend the detector cutoff wavelength to 6 ?m, allowing the coverage of the full midwave infrared (MWIR) transmission window. The quantum dot barrier infrared detector (QD-BIRD) shows infrared response at temperatures up to 225 K.

  9. High Operating Temperature Midwave Quantum Dot Barrier Infrared Detector (QD-BIRD)

    Science.gov (United States)

    Ting, David Z.; Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Mumolo, Jason M.; Gunapala, Sarath D.

    2012-01-01

    The nBn or XBn barrier infrared detector has the advantage of reduced dark current resulting from suppressed Shockley-Read-Hall (SRH) recombination and surface leakage. High performance detectors and focal plane arrays (FPAs) based on InAsSb absorber lattice matched to GaSb substrate, with a matching AlAsSb unipolar electron barrier, have been demonstrated. The band gap of lattice-matched InAsSb yields a detector cutoff wavelength of approximately 4.2 ??m when operating at 150K. We report results on extending the cutoff wavelength of midwave barrier infrared detectors by incorporating self-assembled InSb quantum dots into the active area of the detector. Using this approach, we were able to extend the detector cutoff wavelength to 6 ?m, allowing the coverage of the full midwave infrared (MWIR) transmission window. The quantum dot barrier infrared detector (QD-BIRD) shows infrared response at temperatures up to 225 K.

  10. DSC “peak temperature” versus “maximum slope temperature” in determining TSSD temperature

    Science.gov (United States)

    Khatamian, D.

    2010-10-01

    One of the concerns of the nuclear industry is the deleterious effect of hydrogen on the structural integrity of the reactor core components due to delayed hydride cracking (DHC). The DHC process occurs when hydrogen concentration exceeds the terminal solid solubility (TSS) in the component. Thus, the accurate knowledge of TSS is necessary to predict the lifetime of the components. Differential scanning calorimetry (DSC) is normally used to measure the hydrogen TSS in zirconium alloys. There is a measurable change in the amount of heat absorbed by the specimen when the hydrides dissolve. The hydride dissolution process does not exhibit a well-defined "sharp" change in the heat-flow signal at the transition temperature. A typical DSC heat-flow curve for hydride dissolution has three definite features; "peak temperature" (PT), "maximum slope temperature" (MST) and "completion temperature". The present investigation aims to identify the part of the heat-flow signal that closely corresponds to the TSS temperature for hydride dissolution ( TTSSD). Coupons were cut from a Zr-2.5Nb specimen, which had been previously hydrided using an electrolytic cell to create a surface hydride layer of ˜20 μm thick on all sides of the specimen. The coupons were then annealed isothermally at various temperatures to establish the TTSSD under equilibrium conditions. Subsequently the hydride layer was removed and the coupons were analyzed for TSSD temperature using DSC. The PT and MST for each DSC run were determined and compared to the annealing temperature of the coupon. The results show that the annealing temperature (the equilibrium TTSSD) is much closer to the DSC PT than any other feature of the heat-flow curve.

  11. Coexistence of genotypic and temperature-dependent sex determination in pejerrey Odontesthes bonariensis.

    Directory of Open Access Journals (Sweden)

    Yoji Yamamoto

    Full Text Available In this study, we examined whether a homolog of the master sex-determining gene amhy of Odontesthes hatcheri is present and plays any role in testis determination of pejerrey O. bonariensis, a species otherwise known for its strong temperature-dependent sex determination (TSD. Screening of wild and laboratory-reared pejerrey for amhy revealed a high, although not complete linkage with phenotypic sex. The sex ratio in an amhy+/-/amhy-/- full sibling progeny reared during the thermolabile period of sex determination at an intermediate temperature of 25°C was 68.7% male:31.3% female; all amhy+/- fish developed as males whereas about 2/3 and 1/3 of the amhy-/- were female and male, respectively. Expression analyses revealed that amhy transcription began during embryo stage and decreased by the end of sex determination period. The autosomal amha was present in all individuals regardless of amhy genotype; its expression increased significantly from the end of the same period in the gonads of all amhy+/- but only in part of the amhy-/- animals. After histological gonadal differentiation, all gonads of amhy-/- animals with amha ISH signals were testes and those without it were ovaries. These results suggest that amhy is important for testicular differentiation in pejerrey, at least at intermediate temperatures. Thus, we hypothesize that amhy+/- animals differentiate as males by expression of either amhy alone or amhy and amha together whereas the amhy-/- probably rely solely on amha expression. These findings represent the first clear genomic evidence that genotypic and environmental sex determinants can coexist in species with marked TSD such as the pejerrey. The finding of amhy will make possible to monitor wild pejerrey populations for mismatches between genotypic and phenotypic sex and may prove instrumental for field studies addressing the effects of endocrine disruptors or abnormal temperatures on reproduction and the ecological relevance of TSD

  12. Operational safety practices as determinants of machinery-related injury on Saskatchewan farms.

    Science.gov (United States)

    Narasimhan, Gopinath R; Peng, Yingwei; Crowe, Trever G; Hagel, Louise; Dosman, James; Pickett, William

    2010-07-01

    Agricultural machinery is a major source of injury on farms. The importance of machinery safety practices as potential determinants of injury remains incompletely understood. We examined two such safety practices as risk factors for injury: (1) the presence of safety devices on machinery and (2) low levels of routine machinery maintenance. Our data source was the Saskatchewan Farm Injury Cohort baseline survey (n=2390 farms). Factor analysis was used to create measures of the two operational safety practices. The farm was the unit for all analyses and associations were evaluated using multiple Poisson regression models. Limited presence of safety devices on machinery during farm operations was associated with higher risks for injury (RR 1.94; 95% CI 1.13-3.33; p(trend)=0.02). Lower routine maintenance scores were associated with significantly reduced risks for injury (RR 0.54; 95% CI 0.29-0.98; p(trend)=0.05). The first finding implies that injury prevention programs require continued focus on the use of safety devices on machinery. The second finding could indicate that maintenance itself is a risk factor or that more modern equipment that requires less maintenance places the operator at lower risk. These findings provide etiological data that confirms the practical importance of operational safety practices as components of injury control strategies on farms. Copyright 2010 Elsevier Ltd. All rights reserved.

  13. Determination of Initial Conditions for the Safety Analysis by Random Sampling of Operating Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae-Yong; Park, Moon-Ghu [Sejong University, Seoul (Korea, Republic of)

    2015-05-15

    In most existing evaluation methodologies, which follow a conservative approach, the most conservative initial conditions are searched for each transient scenario through tremendous assessment for wide operating windows or limiting conditions for operation (LCO) allowed by the operating guidelines. In this procedure, a user effect could be involved and a remarkable time and human resources are consumed. In the present study, we investigated a more effective statistical method for the selection of the most conservative initial condition by the use of random sampling of operating parameters affecting the initial conditions. A method for the determination of initial conditions based on random sampling of plant design parameters is proposed. This method is expected to be applied for the selection of the most conservative initial plant conditions in the safety analysis using a conservative evaluation methodology. In the method, it is suggested that the initial conditions of reactor coolant flow rate, pressurizer level, pressurizer pressure, and SG level are adjusted by controlling the pump rated flow, setpoints of PLCS, PPCS, and FWCS, respectively. The proposed technique is expected to contribute to eliminate the human factors introduced in the conventional safety analysis procedure and also to reduce the human resources invested in the safety evaluation of nuclear power plants.

  14. Single-ion polymer electrolyte membranes enable lithium-ion batteries with a broad operating temperature range.

    Science.gov (United States)

    Cai, Weiwei; Zhang, Yunfeng; Li, Jing; Sun, Yubao; Cheng, Hansong

    2014-04-01

    Conductive processes involving lithium ions are analyzed in detail from a mechanistic perspective, and demonstrate that single ion polymeric electrolyte (SIPE) membranes can be used in lithium-ion batteries with a wide operating temperature range (25-80 °C) through systematic optimization of electrodes and electrode/electrolyte interfaces, in sharp contrast to other batteries equipped with SIPE membranes that display appreciable operability only at elevated temperatures (>60 °C). The performance is comparable to that of batteries using liquid electrolyte of inorganic salt, and the batteries exhibit excellent cycle life and rate performance. This significant widening of battery operation temperatures coupled with the inherent flexibility and robustness of the SIPE membranes makes it possible to develop thin and flexible Li-ion batteries for a broad range of applications.

  15. Short-Wave Near-Infrared Spectrometer for Alcohol Determination and Temperature Correction

    Directory of Open Access Journals (Sweden)

    Qingbo Fu

    2012-01-01

    Full Text Available A multichannel short-wave near-infrared (SW-NIR spectrometer module based on charge-coupled device (CCD detection was designed. The design relied on a tungsten lamp enhanced by light emitting diodes, a fixed grating monochromator and a linear CCD array. The main advantages were high optical resolution and an optimized signal-to-noise ratio (0.24 nm and 500, resp. in the whole wavelength range of 650 to 1100 nm. An application to alcohol determination using partial least squares calibration and the temperature correction was presented. It was found that the direct transfer method had significant systematic prediction errors due to temperature effect. Generalized least squares weighting (GLSW method was utilized for temperature correction. After recalibration, the RMSEP found for the 25°C model was 0.53% v/v and errors of the same order of magnitude were obtained at other temperatures (15, 35 and 40°C. And an 2 better than 0.99 was achieved for each validation set. The possibility and accuracy of using the miniature SW-NIR spectrometer and GLSW transfer calibration method for alcohol determination at different temperatures were proven. And the analysis procedure was simple and fast, allowing a strict control of alcohol content in the wine industry.

  16. A Simple Experiment to Determine the Characteristics of an NTC Thermistor for Low-Temperature Measurement Applications

    Science.gov (United States)

    Mawire, A.

    2012-01-01

    A simple low-cost experiment for undergraduate students to determine the characteristics of a negative temperature coefficient of resistance thermistor is presented. The experiment measures the resistance-temperature and voltage-temperature characteristics of the thermistor. Results of the resistance-temperature experiment are used to determine…

  17. A Simple Experiment to Determine the Characteristics of an NTC Thermistor for Low-Temperature Measurement Applications

    Science.gov (United States)

    Mawire, A.

    2012-01-01

    A simple low-cost experiment for undergraduate students to determine the characteristics of a negative temperature coefficient of resistance thermistor is presented. The experiment measures the resistance-temperature and voltage-temperature characteristics of the thermistor. Results of the resistance-temperature experiment are used to determine…

  18. A unique approach to demonstrating that apical bud temperature specifically determines leaf initiation rate in the dicot Cucumis sativus

    NARCIS (Netherlands)

    Savvides, Andreas; Dieleman, Anja; Ieperen, van Wim; Marcelis, Leo F.M.

    2016-01-01

    Main conclusion: Leaf initiation rate is largely determined by the apical bud temperature even when apical bud temperature largely deviates from the temperature of other plant organs.We have long known that the rate of leaf initiation (LIR) is highly sensitive to temperature, but previous studies

  19. Noninvasive optoacoustic temperature determination at the fundus of the eye during laser irradiation.

    Science.gov (United States)

    Schule, Georg; Huttmann, Gereon; Framme, Carsten; Roider, Johann; Brinkmann, Ralf

    2004-01-01

    In all fundus laser treatments of the eye, the temperature increase is not exactly known. In order to optimize treatments, an online temperature determination is preferable. We investigated a noninvasive optoacoustic method to monitor the fundus temperature during pulsed laser irradiation. When laser pulses are applied to the fundus, thermoelastic pressure waves are emitted, due to thermal expansion of the heated tissue. Using a constant pulse energy, the amplitude of the pressure wave increases linearly with an increase in the base temperature of between 30 and 80 degrees C. This method was evaluated in vitro on porcine retinal pigment epithelium (RPE) cell samples and clinically during selective RPE treatment with repetitive microsecond laser pulses. During the irradiation of porcine RPE with a neodymium-doped yttrium (Nd:YLF) laser (527 nm, 1.7 micros, 500 Hz repetition rate, 160 mJ/cm(2)) an increase in the base temperature of 30+/-4 degrees C after 100 pulses was found. During patient treatments, a temperature increase of 60+/-11 degrees C after 100 pulses with a 500-Hz repetition rate and 7+/-1 degrees C after 30 pulses with 100 Hz at 520 mJ/cm(2) was found. All measured data were in good agreement with heat diffusion calculations. Optoacoustic methods can be used to noninvasively determine retinal temperatures during pulsed laser treatment of the eye. This technique can also be adapted to continuous-wave photocoagulation, photodynamic therapy and transpupillary thermotherapy, or other fields of laser-heated tissue.

  20. Stream hydraulics and temperature determine the metabolism of geothermal Icelandic streams

    Directory of Open Access Journals (Sweden)

    Demars B. O.L.

    2011-07-01

    Full Text Available Stream ecosystem metabolism plays a critical role in planetary biogeochemical cycling. Stream benthic habitat complexity and the available surface area for microbes relative to the free-flowing water volume are thought to be important determinants of ecosystem metabolism. Unfortunately, the engineered deepening and straightening of streams for drainage purposes could compromise stream natural services. Stream channel complexity may be quantitatively expressed with hydraulic parameters such as water transient storage, storage residence time, and water spiralling length. The temperature dependence of whole stream ecosystem respiration (ER, gross primary productivity (GPP and net ecosystem production (NEP = GPP − ER has recently been evaluated with a “natural experiment” in Icelandic geothermal streams along a 5–25 °C temperature gradient. There remained, however, a substantial amount of unexplained variability in the statistical models, which may be explained by hydraulic parameters found to be unrelated to temperature. We also specifically tested the additional and predicted synergistic effects of water transient storage and temperature on ER, using novel, more accurate, methods. Both ER and GPP were highly related to water transient storage (or water spiralling length but not to the storage residence time. While there was an additional effect of water transient storage and temperature on ER (r2 = 0.57; P = 0.015, GPP was more related to water transient storage than temperature. The predicted synergistic effect could not be confirmed, most likely due to data limitation. Our interpretation, based on causal statistical modelling, is that the metabolic balance of streams (NEP was primarily determined by the temperature dependence of respiration. Further field and experimental work is required to test the predicted synergistic effect on ER. Meanwhile, since higher metabolic activities allow for higher pollutant degradation or uptake

  1. Determination of volumes in pipeline drain operation; Determinacao de volumes em operacao de drenagem de oleodutos

    Energy Technology Data Exchange (ETDEWEB)

    Pires, Luis Fernando G.; Barreto, Claudio V.; Silva, Bruno G. de [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica. Nucleo de Simulacao Termohidraulica de Dutos - SIMDUT

    2005-07-01

    Usually, pipeline and equipment maintenance requires the partial or fully drainage of the line. To develop this operation, it is necessary to preview the volumes at the drainage points to allocate the available resources to remove the liquid. With this main objective it was developed a numerical tool that is able to calculate the drainage volumes using only the data source from the GIS profile. This is possible if we consider a pipeline at no-flow state where only the gravitational forces can act in the fluid. The present paper uses a spreadsheet to determine the product volumes based in the drain points sequence and considering no flow boundaries along the pipeline. To validate the methodology a comparison is done with the results acquired in two real state drainage operations. (author)

  2. Hydroxyl (6−2 airglow emission intensity ratios for rotational temperature determination

    Directory of Open Access Journals (Sweden)

    R. P. Lowe

    Full Text Available OH(6–2 Q1/P1 and R1/P1 airglow emission intensity ratios, for rotational states up to j' = 4.5, are measured to be lower than implied by transition probabilities published by various authors including Mies, Langhoff et al. and Turnbull and Lowe. Experimentally determined relative values of j' transitions yield OH(6–2 rotational temperatures 2 K lower than Langhoff et al., 7 K lower than Mies and 13 K lower than Turnbull and Lowe.Key words: Atmospheric composition and structure (airglow and aurora; pressure, density and temperature

  3. EXPERIMENTAL DETERMINATION OF TEMPERATURES IN SPARK GENERATED BUBBLES OSCILLATING IN WATER

    Directory of Open Access Journals (Sweden)

    Karel Vokurka

    2017-05-01

    Full Text Available The surface temperatures of the plasma core in the final stages of the first contraction phase of spark-generated bubbles oscillating under ordinary laboratory conditions in a large expanse of water are determined experimentally. The measurement method is based on an analysis of the optical radiation from the bubbles and on the assumption that the plasma core is radiating as a black-body. It is found that the maximum surface temperatures of the plasma core range 4300–8700 K.

  4. Determination of trace calcium by solid substrate-room temperature phosphorimetry

    Institute of Scientific and Technical Information of China (English)

    Jia Ming Liu; Tian Long Yang; Xiao Mei Huang; Xiu Mei Shi; Zhong Bin Shi; Hong Wu; Guo Hui Zhu; Zhi Ming Li; Cui Lian Chen

    2007-01-01

    A new method for the determination of trace calcium by solid substrate-room temperature phosphorimetry is established. It is based on the fact that chromeazurols azurol S-phenanthroline-NaCMC (CAS-phen-NaCMC) system can emit strong and stable room temperature phosphorescence (RTP) on the solid substrate in the filter paper. Ca2+ and phenanthroline can form complex ion Ca(phen)32+, which will form complex [Ca(phen)3(CAS)2] with CAS. In the result, the number of CAS molecules in each spot increased, causing sharp increase of the RTP signal of the CAS-phen-NaCMC system.

  5. Determining Temperature Differential to Prevent Hardware Cross-Contamination in a Vacuum Chamber

    Science.gov (United States)

    Hughes, David

    2013-01-01

    When contamination-sensitive hardware must be tested in a thermal vacuum chamber, cross-contamination from other hardware present in the chamber, or residue from previous tests, becomes a concern. Typical mitigation strategies involve maintaining the temperature of the critical item above that of other hardware elements at the end of the test. A formula for relating the pumping speed of a chamber, the surface area of contamination sources, and the temperatures of the chamber, source, and contamination-sensitive items has been developed. The formula allows the determination of a temperature threshold about which contamination will not condense on the sensitive items. It defines a parameter alpha that is the fraction given by (contaminant source area)/[chamber pumping speed (time under vacuum) 0.5]. If this parameter is less than 10(exp -6), cross-contamination from common spacecraft material will not occur when the sensitive hardware is at the same temperature as the source of contamination (The chamber is isothermal within 5 C.). Knowing when it becomes safe to have the hardware isothermal permits faster and easier thermal transitions when compared with maintaining an arbitrary temperature differential between parts. Furthermore, the standard temperature differential may not be adequate under some conditions (alpha>10(exp -4)).

  6. Temperature-programmed technique accompanied with high-throughput methodology for rapidly searching the optimal operating temperature of MOX gas sensors.

    Science.gov (United States)

    Zhang, Guozhu; Xie, Changsheng; Zhang, Shunping; Zhao, Jianwei; Lei, Tao; Zeng, Dawen

    2014-09-08

    A combinatorial high-throughput temperature-programmed method to obtain the optimal operating temperature (OOT) of gas sensor materials is demonstrated here for the first time. A material library consisting of SnO2, ZnO, WO3, and In2O3 sensor films was fabricated by screen printing. Temperature-dependent conductivity curves were obtained by scanning this gas sensor library from 300 to 700 K in different atmospheres (dry air, formaldehyde, carbon monoxide, nitrogen dioxide, toluene and ammonia), giving the OOT of each sensor formulation as a function of the carrier and analyte gases. A comparative study of the temperature-programmed method and a conventional method showed good agreement in measured OOT.

  7. The dew point temperature as a criterion for optimizing the operating conditions of proton exchange membrane fuel cells

    DEFF Research Database (Denmark)

    Berning, Torsten

    2012-01-01

    of the operating pressure, the stoichiometric flow ratios and the net drag coefficient of water through the membrane. Then, computational modeling results obtained with a previously published model are analyzed and compared with the dew point charts, and it is demonstrated how cell flooding or membrane dry-out can...... be predicted a priori with the aid of these diagrams. Finally, guidelines for the desired cell operating temperature based on the expected dew point temperatures are developed. In the current work these guidelines are limited to the interdigitated flow field design, and they are likely to be different...

  8. Use of AERMOD to Determine a Hydrogen Sulfide Emission Factor for Swine Operations by Inverse Modeling.

    Science.gov (United States)

    O'Shaughnessy, Patrick T; Altmaier, Ralph

    2011-08-01

    This study was conducted to determine both optimal settings applied to the plume dispersion model, AERMOD, and a scalable emission factor for accurately determining the spatial distribution of hydrogen sulfide concentrations in the vicinity of swine concentrated animal feeding operations (CAFOs). These operations emit hydrogen sulfide from both housing structures and waste lagoons. With ambient measurements made at 4 stations within 1 km of large swine CAFOs in Iowa, an inverse-modeling approach applied to AERMOD was used to determine hydrogen sulfide emission rates. CAFO buildings were treated as volume sources whereas nearby lagoons were modeled as area sources. The robust highest concentration (RHC), calculated for both measured and modeled concentrations, was used as the metric for adjusting the emission rate until the ratio of the two RHC levels was unity. Utilizing this approach, an average emission flux rate of 0.57 µg/m(2)-s was determined for swine CAFO lagoons. Using the average total animal weight (kg) of each CAFO, an average emission factor of 6.06 × 10(-7) µg/yr-m(2)-kg was calculated. From studies that measured either building or lagoon emission flux rates, building fluxes, on a floor area basis, were considered equal to lagoon flux rates. The emission factor was applied to all CAFOs surrounding the original 4 sites and surrounding an additional 6 sites in Iowa, producing an average modeled-to-measured RHC ratio of 1.24. When the emission factor was applied to AERMOD to simulate the spatial distribution of hydrogen sulfide around a hypothetical large swine CAFO (1M kg), concentrations 0.5 km from the CAFO were 35 ppb and dropped to 2 ppb within 6 km of the CAFO. These values compare to a level of 30 ppb that has been determined by the State of Iowa as a threshold level for ambient hydrogen sulfide levels.

  9. R&D on an Ultra-Thin Composite Membrane for High-Temperature Operation in PEMFC. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Yuh, C.-Y.

    2003-10-06

    FuelCell Energy developed a novel high-temperature proton exchange membrane for PEM fuel cells for building applications. The laboratory PEM fuel cell successfully operated at 100-400{supdegree}C and low relative humidity to improve CO tolerance, mitigate water and thermal management challenges, and reduce membrane cost. The developed high-temperature membrane has successfully completed 500h 120C endurance testing.

  10. Analysis of the Impact of Decreasing District Heating Supply Temperature on Combined Heat and Power Plant Operation

    OpenAIRE

    Bolonina Alona; Bolonins Genadijs; Blumberga Dagnija

    2014-01-01

    District heating systems are widely used to supply heat to different groups of heat consumers. The district heating system offers great opportunities for combined heat and power production. In this paper decreasing district heating supply temperature is analysed in the context of combined heat and power plant operation. A mathematical model of a CHP plant is developed using both empirical and theoretical equations. The model is used for analysis of modified CHP plant operation modes with redu...

  11. Multi-cycle operation of enhanced biological phosphorus removal (EBPR) with different carbon sources under high temperature.

    Science.gov (United States)

    Shen, Nan; Chen, Yun; Zhou, Yan

    2017-05-01

    Many studies reported that it is challenging to apply enhanced biological phosphorus removal (EBPR) process at high temperature. Glycogen accumulating organisms (GAOs) could easily gain their dominance over poly-phosphate accumulating organisms (PAOs) when the operating temperature was in the range of 25 °C-30 °C. However, a few successful EBPR processes operated at high temperature have been reported recently. This study aimed to have an in-depth understanding on the impact of feeding strategy and carbon source types on EBPR performance in tropical climate. P-removal performance of two EBPR systems was monitored through tracking effluent quality and cyclic studies. The results confirmed that EBPR was successfully obtained and maintained at high temperature with a multi-cycle strategy. More stable performance was observed with acetate as the sole carbon source compared to propionate. Stoichiometric ratios of phosphorus and carbon transformation during both anaerobic and aerobic phases were higher at high temperature than low temperature (20±1 °C) except anaerobic PHA/C ratios within most of the sub-cycles. Furthermore, the fractions of PHA and glycogen in biomass were lower compared with one-cycle pulse feed operation. The microbial community structure was more stable in acetate-fed sequencing batch reactor (C2-SBR) than that in propionate-fed reactor (C3-SBR). Accumulibacter Clade IIC was found to be highly abundant in both reactors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Proposal for determining changes in entropy of semi ideal gas using mean values of temperature functions

    Directory of Open Access Journals (Sweden)

    Pejović Branko B.

    2014-01-01

    Full Text Available In a semi-ideal gas, entropy changes cannot be determined through the medium specific heat capacity in a manner as determined by the change of internal energy and enthalpy, i.e. the amount of heat exchanged. Taking this into account, the authors conducted two models through which it is possible to determine the change in the specific entropy of a semi-ideal gas for arbitrary temperature interval using the spread sheet method, using the mean values of the appropriate functions. The idea is to replace integration, which occurs here in evitably, with mean values of the previous functions. The models are derived based on the functional dependence of the actual specific heat capacity on the temperature. The theorem used is that of the mean value of a function as well as the mathematical properties of the definite integral. The mean value of a fractional function is determined via its integrand while the logarithmic functions were performed by applying a suitable transformation of the differential calculus. The relations derived relation, using the computer program, have enabled the design of appropriate thermodynamic tables through which it is possible to determine the change in entropy of arbitrary state changes in an efficient and rational manner, without the use of calculus or finished forms. In this way, the change in the entropy of a semi-ideal gas is determined for an arbitrary temperature interval using the method which is analogous to that applied in determining the change of internal energy and enthalpy or the amount of heat exchanged, which was the goal of the work. Verification of the proposed method for both the above functions was performed for a a few characteristic semi-ideal gases where change c(T is significant, for the three adopted temperature intervals, for the characteristic change of state. This was compared to the results of the classical integral and the proposed method through the prepared tables. In certain or special cases

  13. A comparison among optical emission spectroscopic methods of determining electron temperature in low pressure argon plasmas

    Institute of Scientific and Technical Information of China (English)

    Niu Tian-Ye; Cao Jin-Xiang; Liu Lei; Liu Jin-Ying; Wang Yan; Wang Liang

    2007-01-01

    In this article, four kinds of optical emission spectroscopic methods of determining electron temperature are used to investigate the relationship between electron temperature and pressure in the cylindrical plasmas of dc glow discharges at low pressures in laboratory by measuring the relative intensities of ArI lines at various pressures. These methods are developed respectively on the basis of the Fermi-Dirac model, corona model, and two kinds of electron collision cross section models according to the kinetic analysis. Their theoretical bases and the conditions to which they are applicable are reviewed, and their calculation results and fitting errors are compared with each other. The investigation has indicated that the electron temperatures obtained by the four methods become consistent with each other when the pressure increases in the low pressure argon plasmas.

  14. Temperature dependence of thermo-optical properties of fluoride glasses determined by thermal lens spectrometry

    Science.gov (United States)

    Lima, S. M.; Catunda, T.; Lebullenger, R.; Hernandes, A. C.; Baesso, M. L.; Bento, A. C.; Miranda, L. C. M.

    1999-12-01

    In this work we report on the use of the thermal lens spectrometry to determine the absolute values of thermal diffusivity, thermal conductivity, and temperature coefficient of optical path-length change of several fluoride glasses. The results showed that flouride glasses doped with minor quantities of Ga, In, and Zn exhibit thermal conductivities and thermal diffusivities roughly 20% larger than that of fluorozirconate (ZBLAN) glasses, whereas their temperature coefficients for the optical path-length change was found to be 50% smaller. This suggests that these fluoride glasses may be considered as promising candidates for high power laser applications. We have also demonstrated how this technique can be used for the complete thermo-optical properties characterization as a function of temperature.

  15. Algorithm to determine electrical submersible pump performance considering temperature changes for viscous crude oils

    Energy Technology Data Exchange (ETDEWEB)

    Valderrama, A. [Petroleos de Venezuela, S.A., Distrito Socialista Tecnologico (Venezuela); Valencia, F. [Petroleos de Venezuela, S.A., Instituto de Tecnologia Venezolana para el Petroleo (Venezuela)

    2011-07-01

    In the heavy oil industry, electrical submersible pumps (ESPs) are used to transfer energy to fluids through stages made up of one impeller and one diffuser. Since liquid temperature increases through the different stages, viscosity might change between the inlet and outlet of the pump, thus affecting performance. The aim of this research was to create an algorithm to determine ESPs' performance curves considering temperature changes through the stages. A computational algorithm was developed and then compared with data collected in a laboratory with a CG2900 ESP. Results confirmed that when the fluid's viscosity is affected by the temperature changes, the stages of multistage pump systems do not have the same performance. Thus the developed algorithm could help production engineers to take viscosity changes into account and optimize the ESP design. This study developed an algorithm to take into account the fluid viscosity changes through pump stages.

  16. A New Method to Determine the Temperature of CMEs Using a Coronagraph Filter System

    CERN Document Server

    Cho, Kyuhyoun; Lim, Eun-kyung; Cho, Kyung-suk; Bong, Su-Chan; Yang, Heesu

    2016-01-01

    The coronagraph is an instrument enables the investigation of faint features in the vicinity of the Sun, particularly coronal mass ejections (CMEs). So far coronagraphic observations have been mainly used to determine the geometric and kinematic parameters of CMEs. Here, we introduce a new method for the determination of CME temperature using a two filter (4025 A and 3934 A) coronagraph system. The thermal motion of free electrons in CMEs broadens the absorption lines in the optical spectra that are produced by the Thomson scattering of visible light originating in the photosphere, which affects the intensity ratio at two different wavelengths. Thus the CME temperature can be inferred from the intensity ratio measured by the two filter coronagraph system. We demonstrate the method by invoking the graduated cylindrical shell (GCS) model for the 3 dimensional CME density distribution and discuss its significance.

  17. Room Temperature Magnetic Determination of the Current Center Line for the ITER TF Coils

    CERN Document Server

    Lerch, Philippe; Buzio, Marco; Negrazus, Marco; Baynham, Elwyn; Sanfilippo, Stephane; Foussat, Arnaud

    2014-01-01

    The ITER tokamak includes 18 superconducting D-shaped toroidal field (IT) coils. Unavoidable shape deformations as well as assembly errors will lead to field errors, which can be modeled with the knowledge of the current center line (CCL). Accurate survey during the entire manufacturing and assembly process, including transfer of survey points, is complex. In order to increase the level of confidence, a room temperature magnetic measurement of the CCL on assembled and closed winding packs is foreseen, prior to insertion into their cold case. In this contribution, we discuss the principle of the CCL determination and present a low frequency ac measurement system under development at PSI, within an ITER framework contract. The largest current allowed to flow in the TF coil at room temperature and the precision requirements for the determination of the CCL loci of the coil are hard boundaries. Eddy currents in the radial plates, the winding pack enclosures, and possibly from iron in the reinforced concrete floor...

  18. TOWARD A REMOVAL OF TEMPERATURE DEPENDENCIES FROM ABUNDANCE DETERMINATIONS: NGC 628

    Energy Technology Data Exchange (ETDEWEB)

    Croxall, Kevin V. [Department of Astronomy, The Ohio State University, 4051 McPherson Laboratory, 140 West 18th Avenue, Columbus, OH 43210 (United States); Smith, J. D.; Pellegrini, E. [Department of Physics and Astronomy, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 (United States); Brandl, B. R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300-RA Leiden (Netherlands); Groves, B. A.; Kreckel, K.; Sandstrom, K. M.; Walter, F.; Schinnerer, E. [Max-Planck-Institut fur Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Kennicutt, R. C.; Galametz, M. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Johnson, B. D. [Institut d' Astrophysique de Paris, UMR7095 CNRS, Université Pierre and Marie Curie, 98 bis Boulevard Arago, F-75014 Paris (France); Armus, L. [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Beirão, P. [Observatoire de Paris, 61 avenue de l' Observatoire, F-75014 Paris (France); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Dale, D. A. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Hinz, J. L. [MMT Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Hunt, L. K. [INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy); Koda, J., E-mail: croxall@astronomy.ohio-state.edu [Department of Physics and Astronomy, SUNY Stony Brook, Stony Brook, NY 11794-3800 (United States)

    2013-11-10

    The metal content of a galaxy, a key property for distinguishing between viable galaxy evolutionary scenarios, strongly influences many of the physical processes in the interstellar medium. An absolute and robust determination of extragalactic metallicities is essential in constraining models of chemical enrichment and chemical evolution. Current gas-phase abundance determinations, however, from optical fine-structure lines are uncertain to 0.8 dex as conversion of these optical line fluxes to abundances is strongly dependent on the electron temperature of the ionized gas. In contrast, the far-infrared (far-IR) emission lines can be used to derive an O{sup ++} abundance that is relatively insensitive to temperature, while the ratio of the optical to far-IR lines provides a consistent temperature to be used in the derivation of an O{sup +} abundance. We present observations of the [O III] 88 μm fine-structure line in NGC 628 that were obtained as part of the Key Insights on Nearby Galaxies: a Far Infared Survey with Herschel program. These data are combined with optical integrated field unit data to derive oxygen abundances for seven H II regions. We find the abundance of these regions to all lie between the high and low values of strong-line calibrations and to be in agreement with estimates that assume temperature fluctuations are present in the H II regions.

  19. A new method to determine oxidative stability of vegetable fats and oils at simulated frying temperature

    Directory of Open Access Journals (Sweden)

    Gertz Christian

    2001-01-01

    Full Text Available A new procedure at simulated frying conditions in our laboratory was developed to monitor frying stability of fats and oils. Water-conditioned silica was prepared and added to the fresh vegetable oil, which was heated for two hours at 170°C. The oil stability at frying temperature was then evaluated by determining the amount of formed dimeric triglycerides The results obtained showed that the stability of the vegetable oils at frying temperature could not be explained by the fatty acid composition alone. Corn oil was observed to be more stable than soybean oil, and rapeseed oil was better than olive oil. It was also observed that crude, non-refined oils were found to have a better heat stability than refin-ed oils. To estimate the effectiveness of synthetic and naturally occurring antioxidants, namely various tocopherols, tocopherol acetate and phytosterol fractions, phenolic compounds like quercetin, oryzanol, ferulic acid, gallates, BHT, BHA and other compounds like ascorbic acid 6-palmitate and squalene were added to refined sunflower and rape seed oil, and their oxidative stability at elevated temperature (OSET values determined. Both linoleic and oleic rich oils gave comparable results for the activity of the various compounds. alpha-tocopherol, tocopherol esters and BHA had low effects on oil stability at frying temperature, while ascorbyl palmitate and some phytosterol fractions were found to have the most stabilizing activity under frying conditions.

  20. Sex determination and differentiation in Aurelia sp.1: the absence of temperature dependence

    Science.gov (United States)

    Liu, Chunsheng; Gu, Zhifeng; Xing, Mengxin; Sun, Yun; Chen, Siqing; Chen, Zhaoting

    2017-03-01

    Cnidarians, being regarded as `basal' metazoan animals, are considered to have relatively high plasticity in terms of sex reversal. In this study we used an experimental approach to demonstrate sexual differentiation and plasticity in benthic polyps and pelagic medusae of Aurelia sp.1 maintained at different temperatures. Results indicated that in Aurelia sp.1, sex differentiation has been determined at the polyp stage and that all medusae originating from a given polyp are, phenotypically, of the same sex. In addition, the sex of polyps budding from the same clone (either male or female) at different temperatures appears to be the same as that of the parent. The sex of medusae that had originated from a known-sex polyp was observed to remain the same as that of the parent, irrespective of differences in strobilation or rearing temperatures. These results indicate that the mechanism of sex determination of Aurelia sp.1. is not influenced by prevailing temperature regimes. A comparison of variability in terms of sexual plasticity of Aurelia sp.1 with that of Hydrozoa and Anthozoa suggests that species characterized by a free-swimming medusa life stage have a high dispersal potential, which probably results in a lower rate of sex reversal.

  1. IN TURNING ON-LINE DETERMINATION OF CUTTING TOOL WEAR RATE BY MEASURING CUTTING TEMPERATURE

    Directory of Open Access Journals (Sweden)

    Murat KIYAK

    1999-01-01

    Full Text Available The improvements of adaptive control and computer aided manufacturing need to be sensitively determined tool wear rate during machining. Reserarchers working on this topic have developed direct and indirect methods. To determine tool wear rate during machining by measuring of cutting temperature is an indirect method. In this study, two measuring techniques, work-tool thermocouple technique and a method that is realized by using a thermocouple assambed by embeding in the tool have been used. Both of them have been tested by obtaining tool wear using hard metal insert and turning mild steel and compared one with the other using different point of views.

  2. Computer-operated analytical platform for the determination of nutrients in hydroponic systems.

    Science.gov (United States)

    Rius-Ruiz, F Xavier; Andrade, Francisco J; Riu, Jordi; Rius, F Xavier

    2014-03-15

    Hydroponics is a water, energy, space, and cost efficient system for growing plants in constrained spaces or land exhausted areas. Precise control of hydroponic nutrients is essential for growing healthy plants and producing high yields. In this article we report for the first time on a new computer-operated analytical platform which can be readily used for the determination of essential nutrients in hydroponic growing systems. The liquid-handling system uses inexpensive components (i.e., peristaltic pump and solenoid valves), which are discretely computer-operated to automatically condition, calibrate and clean a multi-probe of solid-contact ion-selective electrodes (ISEs). These ISEs, which are based on carbon nanotubes, offer high portability, robustness and easy maintenance and storage. With this new computer-operated analytical platform we performed automatic measurements of K(+), Ca(2+), NO3(-) and Cl(-) during tomato plants growth in order to assure optimal nutritional uptake and tomato production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. The determination of the operation parameters at the axial hydraulic turbine

    Science.gov (United States)

    Simedru, A. I.

    2016-08-01

    In the operating point of the monitoring moment there are assumed from process the monitoring measured parameters: the active and reactive power, upstream and downstream water levels (after the intake trash rake and at the outlet of the turbine draft tube), wicket gate and runner opening blades, the differential pressure in the spiral chamber and the hydrounit speed. So, there was established the characteristic curves obtained on analytic basis and similitude and compared with the curves measured experimentally on the hydraulic machines from the power plant. The cavitational coefficient of the machine and the cavitational coefficient of the equipment are in function of the system parameters between them especially the suction head, the runner and wicket gates blades angles of opening. The solution proposed is a method of determining the operating turbine parameters and of the cavitation, by reducing the error caused by the similitude phenomenon, using an accurate estimation of the turbine operating parameters according to the universal diagram of the turbine. The numerical obtained values permit the necessary correlation through a complex function which is able to reduce or eliminate the unwished effects of the cavitation phenomena on the hydraulic turbines of the Iron Gates power plant.

  4. Potential Contributions of Heat Shock Proteins to Temperature-Dependent Sex Determination in the American Alligator

    Science.gov (United States)

    Kohno, S.; Katsu, Y.; Urushitani, H.; Ohta, Y.; Iguchi, T.; Guillette, L. J.

    2010-01-01

    Sex determination in the American alligator depends on the incubation temperature experienced during a thermo-sensitive period (TSP), although sex determination can be ‘reversed’ by embryonic exposure to an estrogenic compound. Thus, temperature and estrogenic signals play essential roles during temperature-dependent sex determination (TSD). The genetic basis for TSD is poorly understood, although previous studies observed that many of the genes associated with genetic sex determination (GSD) are expressed in species with TSD. Heat shock proteins (HSPs), good candidates because of their temperature-sensitive expression, have not been examined in regard to TSD but HSPs have the ability to modify steroid receptor function. A number of HSP cDNAs (HSP27, DNAJ, HSP40, HSP47, HSP60, HSP70A, HSP70B, HSP70C, HSP75, HSP90α, HSP90β, and HSP108) as well as cold-inducible RNA binding protein (CIRBP) and HSP-binding protein (HSPBP) were cloned, and expression of their mRNA in the gonadal-adrenal-mesonephros complex (GAM) was investigated. Embryonic and neonatal GAMs exhibited mRNA for all of the HSPs examined during and after the TSP. One-month-old GAMs were separated into 3 portions (gonad, adrenal gland, and mesonephros), and sexual dimorphism in the mRNA expression of gonadal HSP27 (male > female), gonadal HSP70A (male female) was observed. These findings provide new insights on TSD and suggest that further studies examining the role of HSPs during gonadal development are needed. PMID:19940440

  5. An analytical method for determining the temperature dependent moisture diffusivities of pumpkin seeds during drying process

    Energy Technology Data Exchange (ETDEWEB)

    Can, Ahmet [Department of Mechanical Engineering, University of Trakya, 22030 Edirne (Turkey)

    2007-02-15

    This paper presents an analytical method, which determines the moisture diffusion coefficients for the natural and forced convection hot air drying of pumpkin seeds and their temperature dependence. In order to obtain scientific data, the pumpkin seed drying process was investigated under both natural and forced hot air convection regimes. This paper presents the experimental results in which the drying air was heated by solar energy. (author)

  6. Determining the gelation temperature of β-lactoglobulin using in situ microscopic imaging.

    Science.gov (United States)

    Woo, Hee-Dong; Moon, Tae-Wha; Gunasekaran, Sundaram; Ko, Sanghoon

    2013-09-01

    Evolution of microstructure during heat-induced gelation of β-lactoglobulin (β-LG) was investigated in situ using confocal laser scanning microscopy at various gel-preparation conditions: pH=2, 5, and 7; protein content=5, 10, and 15%; and salt (NaCl) content=0, 0.1, and 0.3 M. The number and area of evolving β-LG clusters were observed as a function of time and temperature and the data were fitted to a log-normal model and sigmoid model, respectively. The gelation temperature (Tgel) of the β-LG system was determined from both the number (Tgel/N) and total area (Tgel/A) of β-LG clusters versus temperature data. The range of Tgel/N and Tgel/A values for all the cases was 68 to 87°C. The effect of pH was the most dominant on Tgel/N and Tgel/A, whereas the effects of β-LG and salt contents were also statistically significant. Therefore, the combined effect of protein concentration, pH, and salt content is critical to determine the overall gel microstructure and Tgel. The Tgel/N and Tgel/A generally agreed well with Tgel determined by dynamic rheometry (Tgel/R). The correlations between Tgel/N and Tgel/A versus Tgel/R were 0.85 and 0.72, respectively. In addition, Tgel/N and Tgel/A values compared well with Tgel/R values reported in the literature. Based on these results, Tgel/N determined via in situ microscopy appears to be a fairly good representative of the traditionally measured gelation temperature, Tgel/R.

  7. Verification Plan for the Concrete Temperature of the MACSTOR/KN-400 Module under Transient State Considering Actual Operating Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Ho; Park, Jeong Eun [KHNP, Daejeon (Korea, Republic of)

    2009-10-15

    This paper covers a verification plan of the results of heat transfer analysis in the MACSTOR/KN-400 on a transient state basis. The transient state reflects several natural environment parameters such as solar loads and daily temperature variations. These factors seriously affect analysis results in terms of concrete temperature and temperature gradients. There are two objectives to verifying the heat analysis results under transient state. First, there is the need to meet the request of the regular body to confirm that concrete temperature stays below the level of the design criteria. Second, it is necessary to recognize how much conservative the analysis is. In actual operating conditions, concrete temperature would be reduced by less conservative conditions.

  8. New approach of gravity wave detection in mesopause temperatures operating an array of airglow spectrometers

    Science.gov (United States)

    Wachter, Paul; Schmidt, Carsten; Wüst, Sabine; Bittner, Michael

    2014-05-01

    GRIPS (Ground based Infrared P-branch Spectrometer) airglow measurements allow the derivation of kinetic temperature in the mesopause region averaged over a field of view of some 10km x 10km. In 2011, three identical GRIPS instruments were setup at Oberpfaffenhofen (11.28°E, 48.09°N), Germany, in a way that their fields of view form an equilateral triangle shape in the mesopause with a horizontal dimension of approximately 70km. Using this setup, GRIPS time series cannot only be analyzed with respect to gravity wave periods, but also spatial wave parameters can be derived. Based on the results of the harmonic analysis the horizontal wavelength, phase speed and the direction of propagation were determined for gravity wave events from February to July 2011. We present distinct relationships between periods, amplitudes, phase speeds and wavelengths, which were identified in this dataset. Further data analysis of the derived wave parameters show preferred directions of propagation and suggest seasonal variations of the wave characteristics. The presentation will be concluded by the introduction of a measurement setup relying on one GRIPS instrument which is equipped with a variably adjustable mirror optic. The capability to scan multiple fields of view during nightly measurements will offer longer-term investigations of mesopause gravity waves.

  9. Optimizing solid oxide fuel cell cathode processing route for intermediate temperature operation

    DEFF Research Database (Denmark)

    Ortiz-Vitoriano, N.; Bernuy-Lopez, Carlos; Ruiz de Larramendi, I.;

    2013-01-01

    -priced raw material and cost-effective production techniques.In this work the perovskite-type La0.6Ca0.4Fe0.8Ni0.2O3 (LCFN) oxide has been used in order to optimize intermediate temperature SOFC cathode processing route. The advantages this material presents arise from the low temperature powder calcination...... of temperatures (800-1000°C). Scanning Electron Microscopy (SEM) studies revealed porous electrode microstructures, even when sintered at a temperature of just 800°C. The competitive performance of the electrodes sintered at low temperatures, combined with the low raw material cost, make these electrodes...

  10. Temperature dependence of the calibration factor of radon and radium determination in water samples by SSNTD

    CERN Document Server

    Hunyadi, I; Hakl, J; Baradacs, E; Dezso, Z

    1999-01-01

    The sensitivity of a sup 2 sup 2 sup 6 Ra determination method of water samples by SSNTD was measured as a function of storage temperature during exposure. The method is based on an etched track type radon monitor, which is closed into a gas permeable foil and is immersed in the water sample. The sample is sealed in a glass vessel and stored for an exposure time of 10-30 days. The sensitivity increased more than a factor of two when the storage temperature was raised from 2 deg. C to 30 deg. C. Temperature dependence of the partition coefficient of radon between water and air provides explanation for this dependence. For practical radio- analytical application the temperature dependence of the calibration factor is given by fitting the sensitivity data obtained by measuring sup 2 sup 2 sup 6 Ra standard solutions (in the activity concentration range of 0.1-48.5 kBq m sup - sup 3) at different storage temperatures.

  11. Assessment of the validity of RTDP application and RAOC operating region determination

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Soon Hong; Cho, Nam Jin; Rho, Hui Cheon; Phaek, Won Phil; Ha, Sang Joon; Kim, Tae Hyeong; Park, Jae Ook; Kim, Yoon Il; Kim, Soo Hyeong [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1996-04-15

    The objectives of this work are to assess the validity of the RTDP(Revised Thermal Design Procedure) application in reload thermal design and safety analysis with emphasis on the method of incorporating the DNB(Departure from Nucleate Boiling) degradation problem of the rotated-grid Vantage05H fuel with IFM(V5H/IFM), and to assess the appropriateness of the determination of RAOC(Relaxed Axial Offset Control) operating region, with respect to the fuel reloading of UlChin Units 1 and 2 (UCN 1/2). The scope and contents of this work are summarized as follows : review of the westinghouse' thermal design procedure RTDP, validity assessment of the RTDP application to UCN 1/2 reload design, follow-up of the DNB recovery program for V/5H/IFM, review of the westinghouse' axial offset control method RAOC, validity assessment of the RAOC application to UCN 1/2 operating region determination.

  12. High night temperatures during grain number determination reduce wheat and barley grain yield: a field study.

    Science.gov (United States)

    García, Guillermo A; Dreccer, M Fernanda; Miralles, Daniel J; Serrago, Román A

    2015-11-01

    Warm nights are a widespread predicted feature of climate change. This study investigated the impact of high night temperatures during the critical period for grain yield determination in wheat and barley crops under field conditions, assessing the effects on development, growth and partitioning crop-level processes driving grain number per unit area (GN). Experiments combined: (i) two contrasting radiation and temperature environments: late sowing in 2011 and early sowing in 2013, (ii) two well-adapted crops with similar phenology: bread wheat and two-row malting barley and (iii) two temperature regimes: ambient and high night temperatures. The night temperature increase (ca. 3.9 °C in both crops and growing seasons) was achieved using purpose-built heating chambers placed on the crop at 19:000 hours and removed at 7:00 hours every day from the third detectable stem node to 10 days post-flowering. Across growing seasons and crops, the average minimum temperature during the critical period ranged from 11.2 to 17.2 °C. Wheat and barley grain yield were similarly reduced under warm nights (ca. 7% °C(-1) ), due to GN reductions (ca. 6% °C(-1) ) linked to a lower number of spikes per m(2) . An accelerated development under high night temperatures led to a shorter critical period duration, reducing solar radiation capture with negative consequences for biomass production, GN and therefore, grain yield. The information generated could be used as a starting point to design management and/or breeding strategies to improve crop adaptation facing climate change.

  13. Prediction of air temperature in the aircraft cabin under different operational conditions

    Directory of Open Access Journals (Sweden)

    Fišer J.

    2013-04-01

    Full Text Available This paper deals with the prediction of the air temperature in the aircraft cabin by means of Computational Fluid Dynamics. The simulations are performed on the CFD model which is based on geometry and cabin interior arrangement of the Flight Test Facility (FTF located at Fraunhofer IBP, Germany. The experimental test flights under three different cabin temperatures were done in FTF and the various data were gathered during these flights. Air temperature in the cabin was measured on probes located near feet, torso and head of each passenger and also surface temperature and air temperature distributed from inlets were measured. The data were firstly analysed in order to obtain boundary conditions for cabin surfaces and inlets. Then the results of air temperature from the simulations were compared with measured data. The suitability and accuracy of the CFD approach for temperature prediction is discussed.

  14. Influence of hydrogen temperature on the stability of a rocket engine combustor operated with hydrogen and oxygen

    Science.gov (United States)

    Gröning, Stefan; Hardi, Justin; Suslov, Dmitry; Oschwald, Michael

    2017-03-01

    Since the late 1960s, low hydrogen injection temperature is known to have a destabilising effect on rocket engines with the propellant combination hydrogen/oxygen. Self-excited combustion instabilities of the first tangential mode have been found recently in a research rocket combustor operated with the propellant combination hydrogen/oxygen with a hydrogen temperature of 95 K. A hydrogen temperature ramping experiment has been performed with this research combustor to analyse the impact of hydrogen temperature on the self-excited combustion instabilities. The temperature was varied between 40 and 135 K. Contrary to past results found in literature, the combustor was found to be stable at low hydrogen temperatures while increased oscillation amplitudes of the first tangential mode were found at higher temperatures of around 100 K and above, which is consistent with previous observations of instabilities in this combustor. Further analysis shows that hydrogen temperature has a strong impact on the combustion chamber resonance frequencies. By varying the hydrogen injection temperature, the frequency of the first tangential mode is shifted to coincide with the second longitudinal resonance frequency of the liquid oxygen injector. Excitation of combustion chamber pressure oscillations was observed during such events.

  15. Effects of Engine Cooling Water Temperature on Performance and Emission Characteristics of a Ci Engine Operated with Biofuel Blend

    Directory of Open Access Journals (Sweden)

    Abul Hossain

    2017-03-01

    Full Text Available The temperature of the coolant is known to have significant influence on engine performance and emissions. Whereas existing literature describes the effects of coolant temperature in engines using fossil derived fuels, very few studies have investigated these effects when biofuel is used. In this study, Jatropha oil was blended separately with ethanol and butanol. It was found that the 80% jatropha oil + 20% butanol blend was the most suitable alternative, as its properties were closest to that of fossil diesel. The coolant temperature was varied between 50°C and 95°C. The combustion process enhanced for both diesel and biofuel blend, when the coolant temperature was increased. The carbon dioxide emissions for both diesel and biofuel blend were observed to increase with temperature. The carbon monoxide, oxygen and lambda values were observed to decrease with temperature. When the engine was operated using diesel, nitrogen oxides emissions correlated in an opposite manner to smoke opacity; however, nitrogen oxides emissions and smoke opacity correlated in an identical manner for biofuel blend. Brake specific fuel consumption was observed to decrease as the temperature was increased and was higher on average when the biofuel was used. The study concludes that both biofuel blend and fossil diesel produced identical correlations between coolant temperature and engine performance. The trends of nitrogen oxides and smoke emissions with cooling temperatures were not identical to fossil diesel when biofuel blend was used in the engine.

  16. Temperature effect on hydrocarbon deposition on molybdenum mirrors under ITER-relevant long-term plasma operation

    NARCIS (Netherlands)

    Rapp, J.; van Rooij, G. J.; Litnovsky, A.; Marot, L.; De Temmerman, G.; Westerhout, J.; Zoethout, E.

    2009-01-01

    Optical diagnostics in ITER will rely on mirrors near the plasma and the deterioration of the reflectivity is a concern. The effect of temperature on the deposition efficiency of hydrocarbons under long-term operation conditions similar to ITER was investigated in the linear plasma generator

  17. Temperature effects on particulate emissions from DPF-equipped diesel trucks operating on conventional and biodiesel fuels

    Science.gov (United States)

    Two diesel trucks equipped with a particulate filter (DPF) were tested at two ambient temperatures (70oF and 20oF), fuels (ultra low sulfur diesel (ULSD) and biodiesel (B20)) and operating loads (a heavy and light weight). The test procedure included three driving cycles, a cold ...

  18. Temperature effect on hydrocarbon deposition on molybdenum mirrors under ITER-relevant long-term plasma operation

    NARCIS (Netherlands)

    Rapp, J.; van Rooij, G. J.; Litnovsky, A.; Marot, L.; De Temmerman, G.; Westerhout, J.; Zoethout, E.

    2009-01-01

    Optical diagnostics in ITER will rely on mirrors near the plasma and the deterioration of the reflectivity is a concern. The effect of temperature on the deposition efficiency of hydrocarbons under long-term operation conditions similar to ITER was investigated in the linear plasma generator Pilot-P

  19. Animal Thermoregulation and the Operative Environmental (Equivalent) Temperature. Physical Processes in Terrestrial and Aquatic Ecosystems, Transport Process.

    Science.gov (United States)

    Stevenson, R. D.

    These materials were designed to be used by life science students for instruction in the application of physical theory to ecosystem operation. Most modules contain computer programs which are built around a particular application of a physical process. Thermoregulation is defined as the ability of an organism to modify its body temperature. This…

  20. Operative temperature drifts and occupant satisfaction with thermal environment in three office buildings using radiant heating/ cooling system

    DEFF Research Database (Denmark)

    Kolarik, Jakub; Toftum, Jørn; Olesen, Bjarne W.

    2015-01-01

    The objective of this study was to analyse operative temperature drifts and occupant satisfaction with thermal environment in office buildings utilizing embedded radiant heating/cooling systems. Three office buildings were investigated: Town Hall in Viborg, Denmark (floor area 19400 m2), IDOM...

  1. Towards a Future of District Heating Systems with Low-Temperature Operation together with Non-Fossil Fuel Heat Sources

    DEFF Research Database (Denmark)

    Tol, Hakan; Dinçer, Ibrahim; Svendsen, Svend

    2012-01-01

    This study focused on investigation of non-fossil fuel heat sources to be supplied to low-energy district heating systems operating in low temperature such as 55 C and 25 C in terms of, respectively, supply and return. Vast variety of heat sources classed in categories such as fossil fuel, renewa...

  2. Experimental determination of temperatures of the inner wall of a boiler combustion chamber for the purpose of verification of a CFD model

    Directory of Open Access Journals (Sweden)

    Petr Trávníček

    2011-01-01

    Full Text Available The paper focuses on the non-destructive method of determination of temperatures in the boiler combustion chamber. This method proves to be significant mainly as regards CFD (Computational Fluid Dynamics simulations of combustion processes, in case of which it is subsequently advisable to verify the data calculated using CFD software application with the actually measured data. Verification of the method was based on usage of reference combustion equipment (130 kW which performs combustion of a mixture of waste sawdust and shavings originating in the course of production of wooden furniture. Measuring of temperatures inside the combustion chamber is – considering mainly the high temperature values – highly demanding and requires a special type of temperature sensors. Furthermore, as regards standard operation, it is not possible to install such sensors without performing structural alterations of the boiler. Therefore, for the purpose of determination of these temperatures a special experimental device was constructed while exploiting a thermal imaging system used for monitoring of the surface temperature of outer wall of the reference boiler. Temperatures on the wall of the boiler combustion chamber were determined on the basis of data measured using the experimental device as well as data from the thermal imaging system. These values might serve for verification of the respective CFD model of combustion equipment.

  3. A fuel cell operating between room temperature and 250 C based on a new phosphoric acid based composite electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Rong [Department of Chemistry, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Xu, Xiaoxiang; Irvine, John T.S. [School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST (United Kingdom); Tao, Shanwen [Department of Chemistry, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); School of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST (United Kingdom)

    2010-10-15

    A phosphoric acid based composite material with core-shell microstructure has been developed to be used as a new electrolyte for fuel cells. A fuel cell based on this electrolyte can operate at room temperature indicating leaching of H{sub 3}PO{sub 4} with liquid water is insignificant at room temperature. This will help to improve the thermal cyclability of phosphoric acid based electrolyte to make it easier for practical use. The conductivity of this H{sub 3}PO{sub 4}-based electrolyte is stable at 250 C with addition of the hydrophilic inorganic compound BPO{sub 4} forming a core-shell microstructure which makes it possible to run a PAFC at a temperature above 200 C. The core-shell microstructure retains after the fuel cell measurements. A power density of 350 mW/cm{sup 2} for a H{sub 2}/O{sub 2} fuel cell has been achieved at 200 C. The increase in operating temperature does not have significant benefit to the performance of a H{sub 2}/O{sub 2} fuel cell. For the first time, a composite electrolyte material for phosphoric acid fuel cells which can operate in a wide range of temperature has been evaluated but certainly further investigation is required. (author)

  4. Operative temperature and thermal sensation assessments in non-air-conditioned multi-storey hostels in Malaysia

    Energy Technology Data Exchange (ETDEWEB)

    Dahlan, N.D. [Department of Architecture, Faculty of Design and Architecture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Jones, P.J.; Alexander, D.K. [Welsh School of Architecture, Cardiff University, Bute Building, King Edward VII Avenue, CF10 3NB (United Kingdom)

    2011-02-15

    This study assessed the influences of operative temperature on occupants' perceptions of indoor thermal condition in three non-air-conditioned multi-storey hostels in Klang Valley, Malaysia. The thermal conditions of 24 measured rooms were recorded with and without an operating ceiling fan from May until July 2007. Measurements were made simultaneously at three different floor levels, namely, at the first, fifth and top floor of each of the case study hostels. A questionnaire survey was completed by 298 female student occupants of the same case study hostels. The results suggested that even though a significance above p < 0.01 was recorded between the operative temperatures with and without fan operation, the temperature difference remained small, i.e., from 0.5 K to 1 K. The findings of the questionnaire survey showed that the occupants perceived the thermal conditions in rooms that were shaded with a projected balcony (shading ratio of 0.9), a long roof overhang (shading ratio of 1.6) and an operable window-to-wall ratio of 0.3 to be thermally comfortable. (author)

  5. Metallicity determination of M dwarfs. Expanded parameter range in metallicity and effective temperature

    Science.gov (United States)

    Lindgren, Sara; Heiter, Ulrike

    2017-08-01

    Context. Reliable metallicity values for late K and M dwarfs are important for studies of the chemical evolution of the Galaxy and advancement of planet formation theory in low-mass environments. Historically it has been challenging to determine the stellar parameters of low-mass stars because of their low surface temperature, which causes several molecules to form in the photospheric layers. In our work we use the fact that infrared high-resolution spectrographs have opened up a new window for investigating M dwarfs. This enables us to use similar methods as for warmer solar-like stars. Aims: Metallicity determination with high-resolution spectra is more accurate than with low-resolution spectra, but it is rather time consuming. In this paper we expand our sample analyzed with this precise method both in metallicity and effective temperature to build a calibration sample for a future revised empirical calibration. Methods: Because of the relatively few molecular lines in the J band, continuum rectification is possible for high-resolution spectra, allowing the stellar parameters to be determined with greater accuracy than with optical spectra. We obtained high-resolution spectra with the CRIRES spectrograph at the Very Large Telescope (VLT). The metallicity was determined using synthetic spectral fitting of several atomic species. For M dwarfs that are cooler than 3575 K, the line strengths of FeH lines were used to determine the effective temperatures, while for warmer stars a photometric calibration was used. Results: We analyzed 16 targets with a range of effective temperature from 3350-4550 K. The resulting metallicities lie between -0.5< [M/H] < +0.4. A few targets have previously been analyzed using low-resolution spectra and we find a rather good agreement with our values. A comparison with available photometric calibrations shows varying agreement and the spread within all empirical calibrations is large. Conclusions: Including the targets from our previous

  6. An empirical determination of upper operational frequency limits of transferred electron mechanism in bulk GaAs and GaN through ensemble Monte Carlo particle simulations

    Science.gov (United States)

    Francis, S.; van Zyl, R. R.; Perold, W. J.

    2015-08-01

    The ensemble Monte Carlo particle simulation technique is used to determine the upper operational frequency limit of the transferred electron mechanism in bulk GaAs and GaN empirically. This mechanism manifests as a decrease in the average velocity of the electrons in the bulk material with an increase in the electric field bias, which yields the characteristic negative slope in the velocity-field curves of these materials. A novel approach is proposed whereby the hysteresis in the simulated dynamic, high-frequency velocity-field curves is exploited. The upper operational frequency limit supported by the material is defined as that frequency, where the average gradient of the dynamic characteristic curve over a radio frequency cycle approaches zero. Effects of temperature and doping level on the operational frequency limit are reported. The frequency limit thus obtained is also useful to predict the highest fundamental frequency of operation of transferred electron devices, such as Gunn diodes, which are based on materials that support the transferred electron mechanism. Based on the method presented here, the upper operational frequency limits of the transferred electron mechanism in bulk GaAs and GaN are 80 and 255 GHz, respectively, at typical doping levels and operating temperatures of Gunn diodes.

  7. Low-threshold room-temperature continuous-wave operation of a terahertz difference-frequency quantum cascade laser source

    Science.gov (United States)

    Fujita, Kazuue; Ito, Akio; Hitaka, Masahiro; Dougakiuchi, Tatsuo; Edamura, Tadataka

    2017-08-01

    The performance of a room-temperature continuous-wave (CW) terahertz source based on intracavity difference-frequency generation in a mid-infrared (λ ∼ 6.8 µm) quantum cascade laser with a dual-upper-state active region is reported. The fabricated buried heterostructure device, with a two-section buried distributed feedback grating, operates at two mid-infrared wavelengths and demonstrates a terahertz output of 2.92 THz with a very low threshold current density of 0.89 kA/cm2 in pulsed operation. Consequently, despite an epitaxial-side-up mounting configuration, the device achieves CW operation at room temperature in which a low CW threshold current density of 1.3 kA/cm2 is obtained.

  8. State of the art of AIM LWIR and VLWIR MCT 2D focal plane detector arrays for higher operating temperatures

    Science.gov (United States)

    Figgemeier, H.; Hanna, S.; Eich, D.; Mahlein, K.-M.; Fick, W.; Schirmacher, W.; Thöt, R.

    2016-05-01

    In this paper AIM presents its latest results on both n-on-p and p-on-n low dark current planar MCT photodiode technology LWIR and VLWIR two-dimensional focal plane detector arrays with a cut-off wavelength >11μm at 80K and a 640x512 pixel format at a 20μm pitch. Thermal dark currents significantly reduced as compared to `Tennant's Rule 07' at a yet good detection efficiency >60% as well as results from NETD and photo response performance characterization are presented. The demonstrated detector performance paces the way for a new generation of higher operating temperature LWIR MCT FPAs with a <30mK NETD up to a 110K detector operating temperature and with good operability.

  9. Infrared Filter Radiometers for Thermodynamic Temperature Determination below 660 °C

    Science.gov (United States)

    Noulkow, N.; Taubert, R. D.; Meindl, P.; Hollandt, J.

    2009-02-01

    At the Physikalisch-Technische Bundesanstalt (PTB), absolutely-calibrated filter radiometers based on silicon photodiodes are routinely used for thermodynamic temperature determinations of blackbodies in the range from the zinc fixed point (FP) (419 °C) up to 3,000 °C. To extend the temperature range down to the tin FP (232 °C), we have designed two new filter radiometers based on indium gallium arsenide (InGaAs) photodiodes with center wavelengths at 1,300 nm and 1,550 nm. For the absolute calibration of the spectral irradiance responsivity of the new InGaAs filter radiometers, the spectral responsivity measurement in the near-infrared (NIR) spectral range has been significantly improved. With a newly developed tuneable laser and monochromator-based cryogenic radiometer facility, the relative standard uncertainty of the NIR spectral responsivity has been reduced from 0.17 % to about 0.03 %. By using the calibrated InGaAs filter radiometer in conjunction with the large-area double sodium heat pipe of the PTB, the first results for the difference between the thermodynamic temperature T and the ITS-90 temperature T 90 in the temperature range from the zinc FP up to the aluminum FP (660 °C) are presented. The values for T - T 90 determined with the new InGaAs filter radiometers are consistent within their relative standard uncertainty of about 30 mK at 419 °C to about 60 mK at 660 °C.

  10. Temperature dependence of protein solubility-determination, application to crystallization, and growth kinetics studies

    Science.gov (United States)

    Rosenberger, Franz

    1993-01-01

    A scintillation method was developed for determinations of the temperature dependence of the solubility, and of nucleation induction times of proteins, in 50-100 mu(l) volumes of solution. Solubility data for lysozyme and horse serum albumin were obtained for various combinations of pH and precipitant concentrations. These data and the nucleation induction information were used for dynamic crystallization control, that is, for the controlled separation of nucleation and growth stages. Individual lysozyme and horse serum albumin crystals were grown in 15-20 mu(l) solution volumes contained in x-ray capillaries. The morphology and kinetics of the growth and dissolution of lysozyme in aqueous solutions with 2.5 percent NaCl and at pH = 4.5 was studied in situ with a depth resolution of 300 A (4 unit cells) by high resolution optical microscopy and digital image processing. The bulk super- or under saturation, sigma, of the solution inside a closed growth cell was controlled by temperature. The growth habit was bound by (110) and (101) faces that grew through layer spreading, although with different growth rate dependencies on supersaturation/temperature. At sigma less than 10 (obtained at higher temperatures) growth was purely kinetic ally controlled, with impurity effects (macrostep formation and kinetic hindrance) becoming significant for sigma less than 2. At sigma greater than 10 (lower temperatures), anisotropies in the interfacial kinetics were more pronounced, with interfacial kinetics and bulk transport becoming equally important to the growth morphology. Growth rates were growth history dependent. The formation of striations (layers of irregularly incorporated solution) was unambiguously correlated with growth temperature variations. Etching exposed dislocations and various high-index faces whose growth morphologies were studied during return to the steady state growth form. Growth steps were observed to originate from two-dimensional nuclei or from outcrops

  11. SOLUBILITY PREDICTION OF SULFONAMIDES AT VARIOUS TEMPERATURES USING A SINGLE DETERMINATION

    Directory of Open Access Journals (Sweden)

    JALAL HANAEE

    2005-04-01

    Full Text Available Solubility of sulphamethoxazole, sulphisoxazole and sulphasalazine in six solvents namely water,methanol, ethanol, 1-propanol, acetone and chloroform were determined at 15, 25, 37 and 45 °C. Two models derived from the Hildebrand solubility approach are proposed for solubility prediction at different temperatures using a single determination. The experimental data of the present work as well as data gathered from the literature have been employed to investigate the accuracy and prediction capability of the proposed models. The overall percent deviations between the predicted and experimental values were 10.78 and 14.63% which were comparable to those of the classical two and three parameter models. The proposed models were much superior to the two pure predictive models i.e., the ones which do not require experimental solubility determination, as the overall percent deviations produced by the latter models were 150.09 and 161.00%.

  12. Determination of optimal parameters in drilling composite materials to minimize the machining temperature using the Taguchi method

    OpenAIRE

    Lopes, Ana C.; Fernandes, Maria G.A.; Ribeiro, J. E.; Fonseca, E.M.M.

    2016-01-01

    Dental implant is used to replace the natural dental root. The process to fix the dental implant in the maxillary bone needs a previous drilling operation. This machining operation involves the increasing of temperature in the drilled region which can reach values higher than 47°C and for this temperature is possible to occur the osseous necrosis [I]. The main goal of this work is to implement an optimization method to define the optimal drilling parameters that cou...

  13. DETERMINATION OF THE OPTIMAL TEMPERING TEMPERATURE IN HARD FACING OF THE FORGING DIES

    Directory of Open Access Journals (Sweden)

    Milan Mutavdžić

    2012-06-01

    Full Text Available Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures.

  14. Determination of the optimal tempering temperature in hard facing of the forging dies

    Directory of Open Access Journals (Sweden)

    Milan Mutavdžić

    2012-05-01

    Full Text Available Here is analyzed selection of the optimal technology for heat treatment during the reparation of the damaged forging dies. Those tools are manufactured from alloyed tool steels for operation at elevated temperatures. Those steels are prone to self-hardening, so in reparatory hard-facing they must be preheated, additionally heated and tempered. During the tempering, in temperature interval 500-600°C, a secondary increase of hardness and decrease of impact toughness occurs, the so-called reversible tempering brittleness. Here is shown that it can be avoided by application of metallurgical and technological measures. Metallurgical measures assume adequate selection of steels. Since the considered steels are per se prone to tempering brittleness, we conducted experimental investigations to define the technological measures to avoid it. Tests on models were conducted: tempering from different temperatures, slow heating and cooling in still air. Hardness measurements showed that at 520°C, the secondary increase of hardness occurs, with drop of the impact toughness. Additional hard-facing tests included samples tempered at various regimes. Samples were prepared for mechanical and metallographic investigations. Results presented illustrate influence of additional heat treatment on structure, hardness and mechanical properties of the hard-faced layers. This enabled establishing the possibility of avoiding the tempering brittleness through technological measures. 

  15. Precise determination of minimum achievable temperature for solid-state optical refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, Denis V., E-mail: d.seletskiy@gmail.com [University of New Mexico, Physics and Astronomy Department, Albuquerque, NM 87131 (United States); Air Force Research Laboratory, Space Vehicles Directorate, Kirtland AFB, NM 87117 (United States); Melgaard, Seth D.; Epstein, Richard I. [University of New Mexico, Physics and Astronomy Department, Albuquerque, NM 87131 (United States); Di Lieto, Alberto; Tonelli, Mauro [NEST Istituto Nanoscienze, CNR, Dipartimento di Fisica Universita di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Sheik-Bahae, Mansoor [University of New Mexico, Physics and Astronomy Department, Albuquerque, NM 87131 (United States)

    2013-01-15

    We measure the minimum achievable temperature (MAT) as a function of excitation wavelength in anti-Stokes fluorescence cooling of high purity Yb{sup 3+}-doped LiYF{sub 4} (Yb:YLF) crystal. Such measurements were obtained by developing a sensitive noncontact thermometry that is based on a two-band differential luminescence spectroscopy using balanced photo-detectors. These measurements are in excellent agreement with the prediction of the laser cooling model and identify MAT of 110 K at 1020 nm, corresponding to E4-E5 Stark manifold transition in Yb:YLF crystal. - Highlights: Black-Right-Pointing-Pointer Laser cooling model for optical refrigeration is reviewed in this article. Black-Right-Pointing-Pointer Importance of crystalline host for cryogenic operation is explained and verified. Black-Right-Pointing-Pointer Novel differential spectroscopy is used for sensitive temperature measurements. Black-Right-Pointing-Pointer Minimum achievable temperature of 110 K in Yb:YLF is measured at E4-E5 transition. Black-Right-Pointing-Pointer Measurements and model predictions are in excellent agreement.

  16. Enhancing nitrification at low temperature with zeolite in a mining operations retention pond

    Directory of Open Access Journals (Sweden)

    Misha eMiazga-Rodriguez

    2012-07-01

    Full Text Available Ammonium nitrate explosives are used in mining operations at Diavik Diamond Mines Inc. in the Northwest Territories, Canada. Residual nitrogen is washed into the mine pit and piped to a nearby retention pond where its removal is accomplished by microbial activity prior to a final water treatment step and release into the sub-Arctic lake, Lac de Gras. Microbial removal of ammonium in the retention pond is rapid during the brief ice-free summer, but often slows under ice cover that persists up to nine months of the year. The aluminosilicate mineral zeolite was tested as an additive to retention pond water to increase rates of ammonium removal at 4 °C. Water samples were collected across the length of the retention pond monthly over a year. The structure of the microbial community (bacteria, archaea, and eukarya, as determined by denaturing gradient gel electrophoresis of PCR-amplified small subunit ribosomal RNA genes, was more stable during cold months than during July-September, when there was a marked phytoplankton bloom. Of the ammonia-oxidizing community, only bacterial amoA genes were consistently detected. Zeolite (10 g was added to retention pond water (100 mL amended with 5 mM ammonium and incubated at 12 °C to encourage development of a nitrifying biofilm. The biofilm community was composed of different amoA phylotypes from those identified in gene clone libraries of native water samples. Zeolite biofilm was added to fresh water samples collected at different times of the year, resulting in a significant increase in laboratory measurements of potential nitrification activity at 4 °C. A significant positive correlation between the amount of zeolite biofilm and potential nitrification activity was observed; rates were unaffected in incubations containing 1-20 mM ammonium. Addition of zeolite to retention ponds in cold environments could effectively increase nitrification rates year round by concentrating active nitrifying biomass.

  17. Temperature-Dependent Sex Determination under Rapid Anthropogenic Environmental Change: Evolution at a Turtle's Pace?

    Science.gov (United States)

    Refsnider, Jeanine M; Janzen, Fredric J

    2016-01-01

    Organisms become adapted to their environment by evolving through natural selection, a process that generally transpires over many generations. Currently, anthropogenically driven environmental changes are occurring orders of magnitude faster than they did prior to human influence, which could potentially outpace the ability of some organisms to adapt. Here, we focus on traits associated with temperature-dependent sex determination (TSD), a classic polyphenism, in a model turtle species to address the evolutionary potential of species with TSD to respond to rapid climate change. We show, first, that sex-ratio outcomes in species with TSD are sensitive to climatic variation. We then identify the evolutionary potential, in terms of heritability, of TSD and quantify the evolutionary potential of 3 key traits involved in TSD: pivotal temperature, maternal nest-site choice, and nesting phenology. We find that these traits display different patterns of adaptive potential: pivotal temperature exhibits moderate heritable variation, whereas nest-site choice and nesting phenology, with considerable phenotypic plasticity, have only modest evolutionary potential to alter sex ratios. Therefore, the most likely response of species with TSD to anthropogenically induced climate change may be a combination of microevolution in thermal sensitivity of the sex-determining pathway and of plasticity in maternal nesting behavior.

  18. Non-invasive product temperature determination during primary drying using tunable diode laser absorption spectroscopy.

    Science.gov (United States)

    Schneid, Stefan C; Gieseler, Henning; Kessler, William J; Pikal, Michael J

    2009-09-01

    The goal of this work was to demonstrate the application of Tunable Diode Laser Absorption Spectroscopy (TDLAS) as a non-invasive method to determine the average product temperature of the batch during primary drying. The TDLAS sensor continuously measures the water vapor concentration and the vapor flow velocity in the spool connecting the freeze-dryer chamber and condenser. Vapor concentration and velocity data were then used to determine the average sublimation rate (g/s) which was subsequently integrated to evaluate the amount of water removed from the product. Position dependent vial heat transfer coefficients (K(v)) were evaluated using the TDLAS sensor data for 20 mL vials during sublimation tests with pure water. TDLAS K(v) data showed good agreement to K(v) data obtained by the traditional gravimetric procedure. K(v) for edge vials was found to be about 20-30% higher than that of center vials. A weighted K(v) was then used to predict a representative average product temperature from TDLAS data in partial and full load freeze drying runs with 5%, 7.5%, or 10% (w/w) sucrose, mannitol, and glycine solutions. TDLAS product temperatures for all freeze-drying runs were within 1-2 degrees C of "center vial" steady state thermocouple data.

  19. Determining Concentrations and Temperatures in Semiconductor Manufacturing Plasmas via Submillimeter Absorption Spectroscopy

    Science.gov (United States)

    Helal, Yaser H.; Neese, Christopher F.; De Lucia, Frank C.; Ewing, Paul R.; Agarwal, Ankur; Craver, Barry; Stout, Phillip J.; Armacost, Michael D.

    2016-06-01

    Plasmas used in the manufacturing processes of semiconductors are similar in pressure and temperature to plasmas used in studying the spectroscopy of astrophysical species. Likewise, the developed technology in submillimeter absorption spectroscopy can be used for the study of industrial plasmas and for monitoring manufacturing processes. An advantage of submillimeter absorption spectroscopy is that it can be used to determine absolute concentrations and temperatures of plasma species without the need for intrusive probes. A continuous wave, 500 - 750 GHz absorption spectrometer was developed for the purpose of being used as a remote sensor of gas and plasma species. An important part of this work was the optical design to match the geometry of existing plasma reactors in the manufacturing industry. A software fitting routine was developed to simultaneously fit for the background and absorption signal, solving for concentration, rotational temperature, and translational temperature. Examples of measurements made on inductively coupled plasmas will be demonstrated. We would like to thank the Texas Analog Center of Excellence/Semiconductor Research Corporation (TxACE/SRC) and Applied Materials for their support of this work.

  20. Determination of temperature dependent drying parameters for potato cylinders and slices during solar drying

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, P.P.; Kumar, Subodh [Centre for Energy Studies, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110 016 (India)

    2008-11-15

    In the present work, a methodology for the determination of temperature dependent drying parameters namely drying constant and lag factor from the experimental drying kinetic curves of food product is proposed. A laboratory scale mixed-mode solar dryer consisting of an inclined flat plate solar collector connected in series to a drying chamber glazed at the top was used to perform natural convection drying experiments with potato cylinders of length 0.05 m and diameter 0.01 m and slices of diameter 0.05 m and thickness 0.01 m. The thin-layer drying equation describing the drying behavior of food products is derived from Fick's law of diffusion. The present analysis reveals that both drying constant and lag factor increase with sample temperature, as expected. Linear and exponential correlations for these parameters are proposed to represent their variation as a function of sample temperature. Results of statistical error analysis indicate that the proposed linear correlation can better represent the experimental drying kinetic curves for both cylinders and slices. Comparison of experimental dimensionless moisture contents with those calculated with variable (temperature dependent) and constant values of drying parameters demonstrates that the predicted results from variable parameters can better simulate the experiments. (author)

  1. Water temperature effects from simulated dam operations and structures in the Middle Fork Willamette River, western Oregon

    Science.gov (United States)

    Buccola, Norman L.; Turner, Daniel F.; Rounds, Stewart A.

    2016-09-14

    Significant FindingsStreamflow and water temperature in the Middle Fork Willamette River (MFWR), western Oregon, have been regulated and altered since the construction of Lookout Point, Dexter, and Hills Creek Dams in 1954 and 1961, respectively. Each year, summer releases from the dams typically are cooler than pre-dam conditions, with the reverse (warmer than pre-dam conditions) occurring in autumn. This pattern has been detrimental to habitat of endangered Upper Willamette River (UWR) Chinook salmon (Oncorhynchus tshawytscha) and UWR winter steelhead (O. mykiss) throughout multiple life stages. In this study, scenarios testing different dam-operation strategies and hypothetical dam-outlet structures were simulated using CE-QUAL-W2 hydrodynamic/temperature models of the MFWR system from Hills Creek Lake (HCR) to Lookout Point (LOP) and Dexter (DEX) Lakes to explore and understand the efficacy of potential flow and temperature mitigation options.Model scenarios were run in constructed wet, normal, and dry hydrologic calendar years, and designed to minimize the effects of Hills Creek and Lookout Point Dams on river temperature by prioritizing warmer lake surface releases in May–August and cooler, deep releases in September–December. Operational scenarios consisted of a range of modified release rate rules, relaxation of power-generation constraints, variations in the timing of refill and drawdown, and maintenance of different summer maximum lake levels at HCR and LOP. Structural scenarios included various combinations of hypothetical floating outlets near the lake surface and hypothetical new outlets at depth. Scenario results were compared to scenarios using existing operational rules that give temperature management some priority (Base), scenarios using pre-2012 operational rules that prioritized power generation over temperature management (NoBlend), and estimated temperatures from a without-dams condition (WoDams).Results of the tested model scenarios led

  2. Junction temperature estimation method for a 600 V, 30A IGBT module during converter operation

    DEFF Research Database (Denmark)

    Choi, U. M.; Blaabjerg, F.; Iannuzzo, F.

    2015-01-01

    This paper proposes an accurate method to estimate the junction temperature using the on-state collector-emitter voltage at high current. By means of the proposed method, the estimation error which comes from the different temperatures of the interconnection materials in the module is compensated...

  3. Determining when a set of compute nodes participating in a barrier operation on a parallel computer are ready to exit the barrier operation

    Science.gov (United States)

    Blocksome, Michael A.

    2011-12-20

    Methods, apparatus, and products are disclosed for determining when a set of compute nodes participating in a barrier operation on a parallel computer are ready to exit the barrier operation that includes, for each compute node in the set: initializing a barrier counter with no counter underflow interrupt; configuring, upon entering the barrier operation, the barrier counter with a value in dependence upon a number of compute nodes in the set; broadcasting, by a DMA engine on the compute node to each of the other compute nodes upon entering the barrier operation, a barrier control packet; receiving, by the DMA engine from each of the other compute nodes, a barrier control packet; modifying, by the DMA engine, the value for the barrier counter in dependence upon each of the received barrier control packets; exiting the barrier operation if the value for the barrier counter matches the exit value.

  4. Human subjects’ perception of indoor environment and their office work performance during exposures to moderate operative temperature ramps

    DEFF Research Database (Denmark)

    Kolarik, Jakub; Toftum, Jørn; Olesen, Bjarne W.

    2008-01-01

    sensation was also included. Subjects filled out questionnaires regarding perception of the environment and intensity of SBS symptoms. Subjects performed simulated office tasks (addition, text typing, proof reading, comprehension and reasoning). Results showed that all tested ramps were recognized....... A linear relation between perceived air quality and temperature (enthalpy) was found. No significant consistent effect of individual temperature ramps on office work performance was found. Increasing operative temperature appeared to slightly decrease speed of addition and text typing regardless the slope...... of perceived air quality. Increasing temperature may negatively influence speed of simple, repetitive tasks of mental work. The significant effect on complex tasks that require concentration, vigilance and logical thinking was not found....

  5. Determine Operating Reactor to Use for the 2016 PCI Level 1 Milestone

    Energy Technology Data Exchange (ETDEWEB)

    Clarno, Kevin T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-01-30

    The Consortium for Advanced Simulation of Light Water Reactors (LWRs) (CASL) Level 1 milestone to “Assess the analysis capability for core-wide [pressurized water reactor] PWR Pellet- Clad Interaction (PCI) screening and demonstrate detailed 3-D analysis on selected sub-region” (L1:CASL.P13.03) requires a particular type of nuclear power plant for the assessment. This report documents the operating reactor and cycles chosen for this assessment in completion of the physics integration (PHI) milestone to “Determine Operating Reactor to use for PCI L1 Milestone” (L3:PHI.CMD.P12.02). Watts Bar Unit 1 experienced (at least) one fuel rod failure in each of cycles 6 and 7, and at least one was deemed to be duty related rather than being primarily related to a manufacturing defect or grid effects. This brief report documents that the data required to model cycles 1–12 of Watts Bar Unit 1 using VERA-CS contains sufficient data to model the PHI portion of the PCI challenge problem. A list of additional data needs is also provided that will be important for verification and validation of the BISON results.

  6. Determination method of load balance ranges for train operation safety under strong wind

    Institute of Scientific and Technical Information of China (English)

    田红旗

    2015-01-01

    The aerodynamic performances of a passenger car and a box car with different heights of windbreak walls under strong wind were studied using the numerical simulations, and the changes of aerodynamic side force, lift force and overturning moment with different wind speeds and wall heights were calculated. According to the principle of static moment balance of vehicles, the overturning coefficients of trains with different wind speeds and wall heights were obtained. Based on the influence of wind speed and wall height on the aerodynamic performance and the overturning stability of trains, a method of determination of the load balance ranges for the train operation safety was proposed, which made the overturning coefficient have nearly closed interval. A min(|A1|+|A2|), s.t.|A1|→|A2|(A1 refers to the downwind overturning coefficient and A2 refers to the upwind overturning coefficient) was found. This minimum value helps to lower the wall height as much as possible, and meanwhile, guarantees the operation safety of various types of trains under strong wind. This method has been used for the construction and improvement of the windbreak walls along the Lanzhou–Xinjiang railway (from Lanzhou to Urumqi, China).

  7. Quantum-mechanical tunneling differential operators, zeta-functions and determinants

    CERN Document Server

    Casahorrán, J

    2002-01-01

    We consider in detail the quantum-mechanical problem associated with the motion of a one-dimensional particle under the action of the double-well potential. Our main tool will be the euclidean (imaginary time) version of the path-integral method. Once we perform the Wick rotation, the euclidean equation of motion is the same as the usual one for the point particle in real time, except that the potential at issue is turned upside down. In doing so, our double-well potential becomes a two-humped potential. As required by the semiclassical approximation we may study the quadratic fluctuations over the instanton which represents in this context the localised finite-action solutions of the euclidean equation of motion. The determinants of the quadratic differential operators are evaluated by means of the zeta-function method. We write in closed form the eigenfunctions as well as the energy eigenvalues corresponding to such operators by using the shape-invariance symmetry. The effect of the multi-instantons configu...

  8. [Application of a device for determination of the transplant length during operation of the aorta-coronary bypass].

    Science.gov (United States)

    Volkov, A M; Khubulava, G G; Paĭvin, A A; Liubimov, A I; Kravchuk, V N

    2012-01-01

    Determination of the necessary length of the bypass is one of the principal stages of operation of the aorta-coronary bypass. The greatest difficulty of the determination of the bypass length is the first-priority applying of proximal anastomoses. It requires the surgeon to have great experience, the operation to be longer. It also makes it necessary to prepare a conduit of deliberately excessive length. A device is proposed for the determination of the necessary bypass length during operation of aorta-coronary bypass consisting of a crocodile grip with a fixed to it polymer tube.

  9. Reliability analysis for determining performance of barrage based on gates operation

    Science.gov (United States)

    Adiningrum, C.; Hadihardaja, I. K.

    2017-06-01

    Some rivers located on a flat slope topography such as Cilemahabang river and Ciherang river in Cilemahabang watershed, Bekasi regency, West Java are susceptible to flooding. The inundation mostly happens near a barrage in the middle and downstream of the Cilemahabang watershed, namely the Cilemahabang and Caringin barrages. Barrages or gated weirs are difficult to exploit since the gate must be kept and operated properly under any circumstances. Therefore, a reliability analysis of the gates operation is necessary to determine the performance of the barrage with respect to the number of gates opened and the gates opening heights. The First Order Second Moment (FOSM) method was used to determine the performance by the reliability index (β) and the probability of failure (risk). It was found that for Cilemahabang Barrage, the number of gates opened with load (L) represents the peak discharge derived from various rainfall (P) respectively one gate with opening height (h=1m) for Preal, two gates (h=1m and h=1,5m) for P50, and three gates (each gate with h=2,5m) for P100. For Caringin Barrage, the results are minimum three gates opened (each gate with h=2,5 m) for Preal, five gates opened (each gate with h=2,5m) for P50, and six gates opened (each gate with h=2,5m) for P100. It can be concluded that a greater load (L) needs greater resistance (R) to counterbalance. Resistance can be added by increasing the number of gates opened and the gate opening height. A higher number of gates opened will lead to the decrease of water level in the upstream of barrage and less risk of overflow.

  10. Method for determining hydrogen mobility as a function of temperature in superconducting niobium cavities

    Science.gov (United States)

    May, Robert

    2008-03-11

    A method for determining the mobility of hydrogen as a function of temperature in superconducting niobium cavities comprising: 1) heating a cavity under test to remove free hydrogen; 2) introducing hydrogen-3 gas into the cavity; 3) cooling the cavity to allow absorption of hydrogen-3; and 4) measuring the amount of hydrogen-3 by: a) cooling the cavity to about 4.degree. K while flowing a known and regulated amount of inert carrier gas such as argon or helium into the cavity; b) allowing the cavity to warm at a stable rate from 4.degree. K to room temperature as it leaves the chamber; and c) directing the exit gas to an ion chamber radiation detector.

  11. Dirac point and transconductance of top-gated graphene field-effect transistors operating at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hopf, T.; Vassilevski, K. V., E-mail: k.vasilevskiy@ncl.ac.uk; Escobedo-Cousin, E.; King, P. J.; Wright, N. G.; O' Neill, A. G.; Horsfall, A. B.; Goss, J. P. [School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Wells, G. H.; Hunt, M. R. C. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom)

    2014-10-21

    Top-gated graphene field-effect transistors (GFETs) have been fabricated using bilayer epitaxial graphene grown on the Si-face of 4H-SiC substrates by thermal decomposition of silicon carbide in high vacuum. Graphene films were characterized by Raman spectroscopy, Atomic Force Microscopy, Scanning Tunnelling Microscopy, and Hall measurements to estimate graphene thickness, morphology, and charge transport properties. A 27 nm thick Al₂O₃ gate dielectric was grown by atomic layer deposition with an e-beam evaporated Al seed layer. Electrical characterization of the GFETs has been performed at operating temperatures up to 100 °C limited by deterioration of the gate dielectric performance at higher temperatures. Devices displayed stable operation with the gate oxide dielectric strength exceeding 4.5 MV/cm at 100 °C. Significant shifting of the charge neutrality point and an increase of the peak transconductance were observed in the GFETs as the operating temperature was elevated from room temperature to 100 °C.

  12. Heat and fuel coupled operation of a high temperature polymer electrolyte fuel cell with a heat exchanger methanol steam reformer

    Science.gov (United States)

    Schuller, G.; Vázquez, F. Vidal; Waiblinger, W.; Auvinen, S.; Ribeirinha, P.

    2017-04-01

    In this work a methanol steam reforming (MSR) reactor has been operated thermally coupled to a high temperature polymer electrolyte fuel cell stack (HT-PEMFC) utilizing its waste heat. The operating temperature of the coupled system was 180 °C which is significantly lower than the conventional operating temperature of the MSR process which is around 250 °C. A newly designed heat exchanger reformer has been developed by VTT (Technical Research Center of Finland LTD) and was equipped with commercially available CuO/ZnO/Al2O3 (BASF RP-60) catalyst. The liquid cooled, 165 cm2, 12-cell stack used for the measurements was supplied by Serenergy A/S. The off-heat from the electrochemical fuel cell reaction was transferred to the reforming reactor using triethylene glycol (TEG) as heat transfer fluid. The system was operated up to 0.4 A cm-2 generating an electrical power output of 427 Wel. A total stack waste heat utilization of 86.4% was achieved. It has been shown that it is possible to transfer sufficient heat from the fuel cell stack to the liquid circuit in order to provide the needed amount for vaporizing and reforming of the methanol-water-mixture. Furthermore a set of recommendations is given for future system design considerations.

  13. The determination of field usability of method measuring temperature fields in the air using an infrared camera

    Directory of Open Access Journals (Sweden)

    Pešek Martin

    2014-03-01

    Full Text Available The article deals with the field usability determination of the method for measuring temperature fields in the air using an infrared camera. This method is based on the visualization of temperature fields on an auxiliary material, which is inserted into the non-isothermal air flow. In this article the field usability is determined from time constants of this method, which define borders of usability for low temperature differences (between air flow temperature and surrounding temperature and for low air flow velocities. The field usability determination for measuring temperature fields in the air can be used in many various applications such as air-heating and air-conditioning where the method of measuring temperature fields in the air by infrared camera can be used.

  14. Determining Land Surface Temperature Relations with Land Use-Land Cover and Air Pollution

    Science.gov (United States)

    Kahya, Ceyhan; Bektas Balcik, Filiz; Burak Oztaner, Yasar; Guney, Burcu

    2016-04-01

    Rapid population growth in conjunction with unplanned urbanization, expansion, and encroachment into the limited agricultural fields and green areas have negative impacts on vegetated areas. Land Surface Temperature (LST), Urban Heat Islands (UHI) and air pollution are the most important environmental problems that the extensive part of the world suffers from. The main objective of this research is to investigate the relationship between LST, air pollution and Land Use-Land Cover (LULC) in Istanbul, using Landsat 8 OLI satellite image. Mono-window algorithm is used to compute LST from Landsat 8 TIR data. In order to determine the air pollution, in-situ measurements of particulate matter (PM10) of the same day as the Landsat 8 OLI satellite image are obtained. The results of this data are interpolated using the Inverse Distance Weighted (IDW) method and LULC categories of Istanbul were determined by using remote sensing indices. Error matrix was created for accuracy assessment. The relationship between LST, air pollution and LULC categories are determined by using regression analysis method. Keywords: Land Surface Temperature (LST), air pollution, Land Use-Land Cover (LULC), Istanbul

  15. Numerical determination of vertical water flux based on soil temperature profiles

    Science.gov (United States)

    Tabbagh, Alain; Cheviron, Bruno; Henine, Hocine; Guérin, Roger; Bechkit, Mohamed-Amine

    2017-07-01

    High sensitivity temperature sensors (0.001 K sensitivity Pt100 thermistors), positioned at intervals of a few centimetres along a vertical soil profile, allow temperature measurements to be made which are sensitive to water flux through the soil. The development of high data storage capabilities now makes it possible to carry out in situ temperature recordings over long periods of time. By directly applying numerical models of convective and conductive heat transfer to experimental data recorded as a function of depth and time, it is possible to calculate Darcy's velocity from the convection transfer term, thus allowing water infiltration/exfiltration through the soil to be determined as a function of time between fixed depths. In the present study we consider temperature data recorded at the Boissy-le-Châtel (Seine et Marne, France) experimental station between April 16th, 2009 and March 8th, 2010, at six different depths and 10-min time intervals. We make use of two numerical finite element models to solve the conduction/convection heat transfer equation and compare their merits. These two models allow us to calculate the corresponding convective flux rate every day using a group of three sensors. The comparison of the two series of calculated values centred at 24 cm shows reliable results for periods longer than 8 days. These results are transformed in infiltration/exfiltration value after determining the soil volumetric heat capacity. The comparison with the rainfall and evaporation data for periods of ten days shows a close accordance with the behaviour of the system governed by rainfall evaporation rate during winter and spring.

  16. Determination of total carbonates in soil archaeometry using a new pressure method with temperature compensation

    Science.gov (United States)

    Barouchas, Pantelis; Koulos, Vasilios; Melfos, Vasilios

    2017-04-01

    For the determination of total carbonates in soil archaeometry a new technique was applied using a multi-sensor philosophy, which combines simultaneous measurement of pressure and temperature. This technology is innovative and complies with EN ISO 10693:2013, ASTM D4373-02(2007) and Soil Science Society of America standard test methods for calcium carbonate content in soils and sediments. The total carbonates analysis is based on a pressure method that utilizes the FOGII Digital Soil CalcimeterTM, which is a portable apparatus. The total carbonate content determined by treating a 1.000 g (+/- 0.001 g) dried sample specimens with 6N hydrochloric acid (HCL) reagent grade, in an enclosed reaction vessel. Carbon dioxide gas evolved during the reaction between the acid and carbonate fraction of the specimen, was measured by the resulting pressure generated, taking in account the temperature conditions during the reaction. Prior to analysis the procedure was validated with Sand/Soil mixtures from BIPEA proficiency testing program with soils of different origins. For applying this new method in archaeometry a total number of ten samples were used from various rocks which are related with cultural constructions and implements in Greece. They represent a large range of periods since the Neolithic times, and were selected because there was an uncertainty about their accurate mineralogical composition especially regarding the presence of carbonate minerals. The results were compared to the results from ELTRA CS580 inorganic carbon analyzer using an infrared cell. The determination of total carbonates for 10 samples from different ancient sites indicated a very good correlation (R2 >0.97) between the pressure method with temperature compensation and the infrared method. The proposed method is quickly and accurate in archaeometry and can replace easily other techniques for total carbonates testing. The FOGII Digital Soil CalcimeterTM is portable and easily can be carried for

  17. Solid polymer electrolyte water electrolyser based on Nafion-TiO{sub 2} composite membrane for high temperature operation

    Energy Technology Data Exchange (ETDEWEB)

    Baglio, V.; Antonucci, V.; Arico, A.S. [CNR-ITAE, Messina (Italy); Matteucci, F.; Martina, F.; Zama, I. [Tozzi Renewable Energy SpA, Mezzano (Italy); Ciccarella, G. [National Nanotechnology Laboratory (NNL) of INFM-CNR, Distretto Tecnologico ISUFI, Innovazione, Universita del Salento, Lecce (Italy); Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Queretaro Sanfandila (Mexico); Ornelas, R.

    2009-06-15

    A composite Nafion-TiO{sub 2} membrane was manufactured by a recast procedure, using an in-house prepared TiO{sub 2}. This membrane has shown promising properties for high temperature operation in an SPE electrolyser allowing to achieve higher performance with respect to a commercial Nafion 115 membrane. This effect is mainly due to the water retention properties of the TiO{sub 2} filler. A promising increase in electrical efficiency was recorded at low current densities for the composite membrane-based SPE electrolyser at high temperature compared to conventional membrane-based devices. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  18. Room-temperature cw operation of an efficient miniaturized Nd:YAG laser end-pumped by a superluminescent diode

    Energy Technology Data Exchange (ETDEWEB)

    Washio, K.; Iwamoto, K.; Inoue, K.; Hino, I.; Matsumoto, S.; Saito, F.

    1976-12-01

    A miniaturized Nd:YAG laser is described, in which a 3-mm-diam x 5.4-mm-long laser rod is end-pumped by a single Al/sub x/Ga/sub 1-x/As superluminescent diode (SLD) having 20-..mu..m x 1.4-nm stripe geometry. A 4.5-mW laser power was obtained at room temperature in a 1-ms pulse operation. Emitted power from the SLD was 50 mW with 1.7% external power efficiency. When continuously pumped, a 1.5-mW laser power was obtained at room temperature. (AIP)

  19. High-Voltage 1-kW dc/dc Converter Developed for Low-Temperature Operation

    Science.gov (United States)

    Patterson, Richard L.

    1998-01-01

    Recently, Lewis developed and demonstrated a high-voltage, 1-kW dc/dc converter that operates from room temperature to -184 C. A power supply designed for use in a NASA ion beam propulsion system was utilized as a starting point for the design of a low- (wide-) temperature dc/dc converter. For safety, we decided to halve the output voltage and power level, so the converter was designed for an 80-Vdc input and a 550-Vdc output at 1 kW.

  20. Determining the optimum process parameter for grinding operations using robust process

    Energy Technology Data Exchange (ETDEWEB)

    Neseli, Suley Man; Asilturk, Ilhan; Celik, Levent [Univ. of Selcuk, Konya (Turkmenistan)

    2012-11-15

    We applied combined response surface methodology (RSM) and Taguchi methodology (TM) to determine optimum parameters for minimum surface roughness (Ra) and vibration (Vb) in external cylindrical grinding. First, an experiment was conducted in a CNC cylindrical grinding machine. The TM using L{sup 27} orthogonal array was applied to the design of the experiment. The three input parameters were workpiece revolution, feed rate and depth of cut; the outputs were vibrations and surface roughness. Second, to minimize wheel vibration and surface roughness, two optimized models were developed using computer aided single objective optimization. The experimental and statistical results revealed that the most significant grinding parameter for surface roughness and vibration is workpiece revolution followed by the depth of cut. The predicted values and measured values were fairly close, which indicates 2 ( 94.99 R{sup 2Ra}=and 2 92.73) R{sup 2Vb}=that the developed models can be effectively used to predict surface roughness and vibration in the grinding. The established model for determination of optimal operating conditions shows that a hybrid approach can lead to success of a robust process.

  1. Receiver Operating Characteristic (ROC to Determine Cut-Off Points of Biomarkers in Lung Cancer Patients

    Directory of Open Access Journals (Sweden)

    Heidi L. Weiss

    2004-01-01

    Full Text Available The role of biomarkers in disease prognosis continues to be an important investigation in many cancer studies. In order for these biomarkers to have practical application in clinical decision making regarding patient treatment and follow-up, it is common to dichotomize patients into those with low vs. high expression levels. In this study, receiver operating characteristic (ROC curves, area under the curve (AUC of the ROC, sensitivity, specificity, as well as likelihood ratios were calculated to determine levels of growth factor biomarkers that best differentiate lung cancer cases versus control subjects. Selected cut-off points for p185erbB-2 and EGFR membrane appear to have good discriminating power to differentiate control tissues versus uninvolved tissues from patients with lung cancer (AUC = 89% and 90%, respectively; while AUC increased to at least 90% for selected cut-off points for p185erbB-2 membrane, EGFR membrane, and FASE when comparing between control versus carcinoma tissues from lung cancer cases. Using data from control subjects compared to patients with lung cancer, we presented a simple and intuitive approach to determine dichotomized levels of biomarkers and validated the value of these biomarkers as surrogate endpoints for cancer outcome.

  2. Comparative Studies on Low Noise Greases Operating under High Temperature Oxidation Conditions

    Institute of Scientific and Technical Information of China (English)

    Xiong Chunhua; Mi Hongying; Feng Qiang; Wu Baojie

    2014-01-01

    Oxidation induction time (OIT) testing by differential scanning calorimetry (DSC) was used to evaluate the oxidation resistance of lubricating greases. Under the high temperature condition, bearing noise was detected when grease passed the initial stable stage of oxidation. The chemical and physical structure of grease samples before and after high tem-perature oxidation were also analyzed by FT-IR spectrometry and scanning electron microscopy (SEM), then the effects of oxidation at high temperature on bearing noise were investigated. It is found out that for lithium greases, oxidation of base oil and thickener is the main reason responsible for the increasing bearing noise. As regards the polyurea greases, the change of ifber microstructure at high temperature is the main reason for the increasing bearing noise.

  3. Evaluation of Artificial Neural Network-Based Temperature Control for Optimum Operation of Building Envelopes

    National Research Council Canada - National Science Library

    Moon, Jin; Lee, Ji-Hyun; Kim, Sooyoung

    2014-01-01

    .... Numerical comparative performance tests for the ANN-based temperature control logic and conventional non-ANN-based counterpart were conducted for single skin enveloped and double skin enveloped...

  4. High-Temperature Stable Operation of Nanoribbon Field-Effect Transistors

    Directory of Open Access Journals (Sweden)

    Kim Sangsig

    2010-01-01

    Full Text Available Abstract We experimentally demonstrated that nanoribbon field-effect transistors can be used for stable high-temperature applications. The on-current level of the nanoribbon FETs decreases at elevated temperatures due to the degradation of the electron mobility. We propose two methods of compensating for the variation of the current level with the temperature in the range of 25–150°C, involving the application of a suitable (1 positive or (2 negative substrate bias. These two methods were compared by two-dimensional numerical simulations. Although both approaches show constant on-state current saturation characteristics over the proposed temperature range, the latter shows an improvement in the off-state control of up to five orders of magnitude (−5.2 × 10−6.

  5. A Plateau-Burning, Low Temperature-Operable Solid Propellant for Mars Sample Return Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Mars ascent vehicle (MAV) is required to endure a long space transit time, high-g loading during planetary entry, and high launch loads, all at low temperatures...

  6. A study on positive-feedback configuration of a bipolar SiC high temperature operational amplifier

    Science.gov (United States)

    Kargarrazi, Saleh; Lanni, Luigia; Zetterling, Carl-Mikael

    2016-02-01

    This paper reports on the design and implementation of an integrated operational amplifier in bipolar SiC, and elaborates on its operation in positive-feedback configuration.The opamp is studied in different feedback setups: closed-loop compensated amplifier, comparator with hysteresis (Schmitt trigger), and as a relaxation oscillator. Measurement results suggest a stable closed-loop opamp with ∼40 dB gain, a Schmitt trigger with constant threshold levels over a wide temperature range, and a relaxation oscillator tested up to 540 kHz. All the setups were tested from 25 °C up to 500 °C.

  7. Current Sharing inside a High Power IGBT Module at the Negative Temperature Coefficient Operating Region

    CERN Document Server

    Asimakopoulos, Panagiotis; Bongiorno, M; Thiringer, T

    2016-01-01

    This work investigates the current sharing effect of a high power Soft Punch Through IGBT module in the Negative Temperature Coefficient region. The unbalanced current sharing between two of the substrates is demonstrated for different current and temperature levels and its impact on the thermal stressing of the device is evaluated. The results indicate that the current asymmetry does not lead to a significant thermal stressing unbalance between the substrates.

  8. A novel coupled VM-PT cryocooler operating at liquid helium temperature

    Science.gov (United States)

    Pan, Changzhao; Zhang, Tong; Zhou, Yuan; Wang, Junjie

    2016-07-01

    This paper presents experimental results on a novel two-stage gas-coupled VM-PT cryocooler, which is a one-stage VM cooler coupled a pulse tube cooler. In order to reach temperatures below the critical point of helium-4, a one-stage coaxial pulse tube cryocooler was gas-coupled on the cold end of the former VM cryocooler. The low temperature inertance tube and room temperature gas reservoir were used as phase shifters. The influence of room temperature double-inlet was first investigated, and the results showed that it added excessive heat loss. Then the inertance tube, regenerator and the length of the pulse tube were researched experimentally. Especially, the DC flow, whose function is similar to the double-orifice, was experimentally studied, and shown to contribute about 0.2 K for the no-load temperature. The minimum no-load temperature of 4.4 K was obtained with a pressure ratio near 1.5, working frequency of 2.2 Hz, and average pressure of 1.73 MPa.

  9. Expanded Operational Temperature Range for Space Rated Li-Ion Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Quallion's response to this solicitation calls for expanding the nominal operation range of its space rated lithium ion cells, while maintaining their long life...

  10. Lithium Battery Electrolytes for Long Cycle Life and Wide Operating Temperature Range Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New lithium battery electrolytes must be developed if these they are to be successfully deployed on NASA Platforms operating at -100oC to +100oC. Giner, Inc. has...

  11. Expanded Operational Temperature Range for Space Rated Li-Ion Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Quallion's Phase II proposal calls for expanding the nominal operation range of its space rated lithium ion cells, while maintaining their long life capabilities. To...

  12. Determining Energy Eigenvalues of Dynamic Systems by Finding 'Eigen-operator' ofSquare of Schroedinger Operator

    Institute of Scientific and Technical Information of China (English)

    FANHong-Yi; XUXue-Fen; LIChao

    2004-01-01

    A newly transparent approach for determining energy eigenvalues is proposed, which is finding the ‘eigen-operator' of the square of the Schroedinger operator. As three examples, we discuss the energy level of a nondegenerate parametric amplifier, an angular momentum system and a ring shape of coupled oscillators.

  13. New precise determination of the high temperature unusual temperature dependent thermopower of liquid divalent cadmium and zinc

    Energy Technology Data Exchange (ETDEWEB)

    Giordanengo, B. [Laboratoire de Physique des Liquides et des Interfaces, 1 Boulevard Arago, 57 078 Metz Cedex 03 (France). E-mail: boris at lpli.sciences.univ-metz.fr; Ben Moussa, A.; Makradi, A.; Chaaba, H.; Gasser, J.-G. [Laboratoire de Physique des Liquides et des Interfaces, 1 Boulevard Arago, 57 078 Metz Cedex 03 (France)

    2000-04-17

    We do not know any precise measurement of the absolute thermopower (ATP) of liquid cadmium and zinc at high temperatures. For liquid cadmium, there are, in the literature, apparent contradictory results. Bath and Kliem and North and Wagner observed that the ATP increases with temperature between 350 deg. C and 650 deg. C, but Bradley observed the opposite behaviour between 600 deg. C and 750 deg. C. In this work we measured accurately the absolute thermopower of liquid cadmium from the melting point up to 900 deg. C. We find a maximum around 520 deg. C, and then the thermopower decreases down to a surprising negative value. To our knowledge, it is the first time that such an unusual behaviour is reported. Nevertheless, it is qualitatively consistent with all the authors mentioned and the apparent contradictory results should only be due to the different temperature ranges of measurements. Using the ATP expression from the Faber-Ziman formalism, we can fit very well the experimental absolute thermopower versus temperature curve with only one adjustable parameter. For this, we have considered that the temperature dependence of the ATP is dominated by the resistivity, and we have introduced the experimental resistivity temperature dependence in the ATP expression. The very good fitting quality demonstrates that our hypothesis is consistent. In contrast, the liquid zinc ATP only increases with temperature. Nevertheless, near 1100 deg. C, the highest temperature achieved, it shows saturation that may be an indication of a decrease at higher temperature. The same type of fitting gives also quite good results. (author)

  14. New precise determination of the high temperature unusual temperature dependent thermopower of liquid divalent cadmium and zinc

    Science.gov (United States)

    Giordanengo, B.; Ben Moussa, A.; Makradi, A.; Chaaba, H.; Gasser, J.-G.

    2000-04-01

    We do not know any precise measurement of the absolute thermopower (ATP) of liquid cadmium and zinc at high temperatures. For liquid cadmium, there are, in the literature, apparent contradictory results. Bath and Kliem and North and Wagner observed that the ATP increases with temperature between 350 °C and 650 °C, but Bradley observed the opposite behaviour between 600 °C and 750 °C. In this work we measured accurately the absolute thermopower of liquid cadmium from the melting point up to 900 °C. We find a maximum around 520 °C, and then the thermopower decreases down to a surprising negative value. To our knowledge, it is the first time that such an unusual behaviour is reported. Nevertheless, it is qualitatively consistent with all the authors mentioned and the apparent contradictory results should only be due to the different temperature ranges of measurements. Using the ATP expression from the Faber-Ziman formalism, we can fit very well the experimental absolute thermopower versus temperature curve with only one adjustable parameter. For this, we have considered that the temperature dependence of the ATP is dominated by the resistivity, and we have introduced the experimental resistivity temperature dependence in the ATP expression. The very good fitting quality demonstrates that our hypothesis is consistent. In contrast, the liquid zinc ATP only increases with temperature. Nevertheless, near 1100 °C, the highest temperature achieved, it shows saturation that may be an indication of a decrease at higher temperature. The same type of fitting gives also quite good results.

  15. Improved Determination of the Location of the Temperature Maximum in the Corona

    Science.gov (United States)

    Lemaire, J. F.; Stegen, K.

    2016-12-01

    The most used method to calculate the coronal electron temperature [Te (r)] from a coronal density distribution [ne (r)] is the scale-height method (SHM). We introduce a novel method that is a generalization of a method introduced by Alfvén ( Ark. Mat. Astron. Fys. 27, 1, 1941) to calculate Te(r) for a corona in hydrostatic equilibrium: the "HST" method. All of the methods discussed here require given electron-density distributions [ne (r)] which can be derived from white-light (WL) eclipse observations. The new "DYN" method determines the unique solution of Te(r) for which Te(r → ∞) → 0 when the solar corona expands radially as realized in hydrodynamical solar-wind models. The applications of the SHM method and DYN method give comparable distributions for Te(r). Both have a maximum [T_{max}] whose value ranges between 1 - 3 MK. However, the peak of temperature is located at a different altitude in both cases. Close to the Sun where the expansion velocity is subsonic (r < 1.3 R_{⊙}) the DYN method gives the same results as the HST method. The effects of the other free parameters on the DYN temperature distribution are presented in the last part of this study. Our DYN method is a new tool to evaluate the range of altitudes where the heating rate is maximum in the solar corona when the electron-density distribution is obtained from WL coronal observations.

  16. A geometry-based approach to determining time-temperature superposition shifts in aging experiments

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Amitesh

    2015-12-21

    A powerful way to expand the time and frequency range of material properties is through a method called time-temperature superposition (TTS). Traditionally, TTS has been applied to the dynamical mechanical and flow properties of thermo-rheologically simple materials, where a well-defined master curve can be objectively and accurately obtained by appropriate shifts of curves at different temperatures. However, TTS analysis can also be useful in many other situations where there is scatter in the data and where the principle holds only approximately. In such cases, shifting curves can become a subjective exercise and can often lead to significant errors in the long-term prediction. This mandates the need for an objective method of determining TTS shifts. Here, we adopt a method based on minimizing the “arc length” of the master curve, which is designed to work in situations where there is overlapping data at successive temperatures. We examine the accuracy of the method as a function of increasing noise in the data, and explore the effectiveness of data smoothing prior to TTS shifting. We validate the method using existing experimental data on the creep strain of an aramid fiber and the powder coarsening of an energetic material.

  17. Determination of Proper Austenitization Temperatures for Hot Stamping of AISI 4140 Steel

    Science.gov (United States)

    Samadian, Pedram; Parsa, Mohammad Habibi; Shakeri, Amid

    2014-04-01

    High strength steels are desirable materials for use in automobile bodies in order to reduce vehicle weight and increase the safety of car passengers, but steel grades with high strength commonly show poor formability. Recently, steels with controlled microstructures and compositions are used to gain adequate strength after hot stamping while maintaining good formability during processing. In this study, microstructure evolutions and changes in mechanical properties of AISI 4140 steel sheets resulting from the hot stamping process at different austenitization temperatures were investigated. To determine the proper austenitization temperatures, the results were compared with those of the cold-worked and cold-worked plus quench-tempered specimens. Comparisons showed that the austenitization temperatures of 1000 and 1100 °C are proper for hot stamping of 3-mm-thick AISI 4140 steel sheets due to the resultant martensitic microstructure which led to the yield and ultimate tensile strength of 1.3 and 2.1 GPa, respectively. Such conditions resulted in more favorable simultaneous strength and elongation than those of hot-stamped conventional boron steels.

  18. A precise and accurate determination of the cosmic microwave background temperature at z=0.89

    CERN Document Server

    Muller, S; Black, J H; Curran, S J; Horellou, C; Aalto, S; Combes, F; Guelin, M; Henkel, C

    2012-01-01

    According to the Big Bang theory and as a consequence of adiabatic expansion of the Universe, the temperature of the cosmic microwave background (CMB) increases linearly with redshift. This relation is, however, poorly explored, and detection of any deviation would directly lead to (astro-)physics beyond the standard model. We aim at measuring the temperature of the CMB with an accuracy of a few percent at z=0.89 toward the molecular absorber in the galaxy lensing the quasar PKS1830-211. We adopt a Monte-Carlo Markov Chain approach, coupled with predictions from the non-LTE radiative transfer code RADEX, to solve the excitation of a set of various molecular species directly from their spectra. We determine Tcmb=5.08 pm 0.10 K at 68% confidence level. Our measurement is consistent with the value Tcmb=5.14 K predicted by the standard cosmological model with adiabatic expansion of the Universe. This is the most precise determination of Tcmb at z>0 to date.

  19. Use of Temperature and Humidity Sensors to Determine Moisture Content of Oolong Tea

    Directory of Open Access Journals (Sweden)

    Andrew Chen

    2014-08-01

    Full Text Available The measurement of tea moisture content is important for processing and storing tea. The moisture content of tea affects the quality and durability of the product. Some electrical devices have been proposed to measure the moisture content of tea leaves but are not practical. Their performance is influenced by material density and packing. The official oven method is time-consuming. In this study, the moisture content of Oolong tea was measured by the equilibrium relative humidity technique. The equilibrium relative humidity, and temperature, of tea materials were measured by using temperature and relative humidity sensors. Sensors were calibrated, and calibration equations were established to improve accuracy. The moisture content was calculated by using an equilibrium moisture content model. The error of the moisture content determined with this method was within 0.5% w.b. at moisture <15% w.b. Uncertainty analysis revealed that the performance of the humidity sensor had a significant effect on the accuracy of moisture determination.

  20. Integrated pressure and temperature sensor with high immunity against external disturbance for flexible endoscope operation

    Science.gov (United States)

    Maeda, Yusaku; Maeda, Kohei; Kobara, Hideki; Mori, Hirohito; Takao, Hidekuni

    2017-04-01

    In this study, an integrated pressure and temperature sensor device for a flexible endoscope with long-term stability in in vivo environments was developed and demonstrated. The sensor, which is embedded in the thin wall of the disposable endoscope hood, is intended for use in endoscopic surgery. The device surface is coated with a Cr layer to prevent photoelectronic generation induced by the strong light of the endoscope. The integrated temperature sensor allows compensation for the effect of the temperature drift on a pressure signal. The fabricated device pressure resolution is 0.4 mmHg; the corresponding pressure error is 3.2 mmHg. The packaged device was used in a surgical simulation in an animal experiment. Pressure and temperature monitoring was achieved even in a pH 1 acid solution. The device enables intraluminal pressure and temperature measurements of the stomach, which facilitate the maintenance of internal stomach conditions. The applicability of the sensor was successfully demonstrated in animal experiments.

  1. DETERMINATION OF MAIN OUTPUT PARAMETERS FOR HYDROFICATED CONSTRUCTION AND ROAD-BUILDING MACHINES AT OPERATIONAL STAGE OF THEIR LIFE CYCLE

    Directory of Open Access Journals (Sweden)

    A. N. Maximenko

    2014-01-01

    Full Text Available Usage efficiency of mechanical engineering products is determined by level of their operating capability. Expenses connected with provision of operating capability for the whole operational period exceed initial cost of the products by 6-10-fold. Moreover , while being used the expenses have a tendency to increase with reduction of output parameters that ensure product application efficiency for its intended purpose. It is necessary to take into account these changes at manufacturing stages of mechanical engineering products. Maximum efficiency can be obtained at the operational stage of the product life cycle only as a result of complex and interrelated measures during designing, manufacturing and usage of the specific product for its intended purpose with due account of its output parameter dynamics. While using the product an analysis of its output parameter dynamics will make it possible to determine maximum value of the operating capability, operational expenses and best practices for obtaining maximum profit per operating time unit.Taking hydroficated excavators of the 5th grade as an example the paper presents dynamics of main output parameters at the operational stage of their life cycle; reveals the main factor influencing on intensity of hydroficated machine operating capability reduction; substantiates an expediency of taking into account output parameter dynamics while evaluating efficiency of its usage; proposes a methodology for determination of or a pay-off time period for recoupment of expenses pertaining to machine procurement and optimum time period for operational stage, its life cycle that corresponds to obtaining maximum profit.Nowadays constant values of main output parameters (operating capability, self cost of machine-hour corresponding to the beginning of operation are to be taken into account while determining expediency of machine creation. Practically they significantly change in the process of machine operation this

  2. Palaeomagnetic Emplacement Temperature Determinations of Pyroclastic and Volcaniclastic Deposits in Southern African Kimberlite Pipes

    Science.gov (United States)

    Fontana, G.; Mac Niocaill, C.; Brown, R.; Sparks, R. S.; Matthew, F.; Gernon, T. M.

    2009-12-01

    Kimberlites are complex, ultramafic and diamond-bearing volcanic rocks preserved in volcanic pipes, dykes and craters. The formation of kimberlite pipes is a strongly debated issue and two principal theories have been proposed to explain pipe formation: (1) the explosive degassing of magma, and (2) the interaction of rising magma with groundwater (phreatomagmatism). Progressive thermal demagnetization studies are a powerful tool for determining the emplacement temperatures of ancient volcanic deposits and we present the first application of such techniques to kimberlite deposits. Lithic clasts were sampled from a variety of lithofacies, from three pipes for which the internal geology is well constrained (A/K1 pipe, Orapa Mine, Botswana and the K1 and K2 pipes, Venetia Mine, South Africa). The sampled deposits included massive and layered vent-filling breccias with varying abundances of lithic inclusions and layered crater-filling pyroclastic deposits, talus breccias and volcaniclastic breccias. Lithic clasts sampled from layered and massive vent-filling pyroclastic deposits in A/K1 were emplaced at >590° C. Results from K1 and K2 provide a maximum emplacement temperature limit for vent-filling breccias of 420-460° C; and constrain equilibrium deposit temperatures at 300-340° C. Crater-filling volcaniclastic kimberlite breccias and talus deposits from A/K1 were emplaced at ambient temperatures, consistent with infilling of the pipe by post-eruption epiclastic processes. Identified within the epiclastic crater-fill succession is a laterally extensive 15-20 metre thick kimberlite pyroclastic flow deposit emplaced at temperatures of 220-440° C. It overlies the post-eruption epiclastic units and is considered an extraneous pyroclastic kimberlite deposit erupted from another kimberlite vent. The results provide important constraints on kimberlite emplacement mechanisms and eruption dynamics. Emplacement temperatures of >590°C for pipe-filling pyroclastic deposits

  3. Soil temperature determines the reaction of olive cultivars to Verticillium dahliae pathotypes.

    Directory of Open Access Journals (Sweden)

    Rocío Calderón

    Full Text Available Development of Verticillium wilt in olive, caused by the soil-borne fungus Verticillium dahliae, can be influenced by biotic and environmental factors. In this study we modeled i the combined effects of biotic factors (i.e., pathotype virulence and cultivar susceptibility and abiotic factors (i.e., soil temperature on disease development and ii the relationship between disease severity and several remote sensing parameters and plant stress indicators.Plants of Arbequina and Picual olive cultivars inoculated with isolates of defoliating and non-defoliating V. dahliae pathotypes were grown in soil tanks with a range of soil temperatures from 16 to 32°C. Disease progression was correlated with plant stress parameters (i.e., leaf temperature, steady-state chlorophyll fluorescence, photochemical reflectance index, chlorophyll content, and ethylene production and plant growth-related parameters (i.e., canopy length and dry weight.Disease development in plants infected with the defoliating pathotype was faster and more severe in Picual. Models estimated that infection with the defoliating pathotype was promoted by soil temperatures in a range of 16 to 24°C in cv. Picual and of 20 to 24°C in cv. Arbequina. In the non-defoliating pathotype, soil temperatures ranging from 16 to 20°C were estimated to be most favorable for infection. The relationship between stress-related parameters and disease severity determined by multinomial logistic regression and classification trees was able to detect the effects of V. dahliae infection and colonization on water flow that eventually cause water stress.Chlorophyll content, steady-state chlorophyll fluorescence, and leaf temperature were the best indicators for Verticillium wilt detection at early stages of disease development, while ethylene production and photochemical reflectance index were indicators for disease detection at advanced stages. These results provide a better understanding of the differential

  4. Battery Internal Temperature Estimation for LiFePO4 Battery Based on Impedance Phase Shift under Operating Conditions

    Directory of Open Access Journals (Sweden)

    Jiangong Zhu

    2017-01-01

    Full Text Available An impedance-based temperature estimation method is investigated considering the electrochemical non-equilibrium with short-term relaxation time for facilitating the vehicular application. Generally, sufficient relaxation time is required for battery electrochemical equilibrium before the impedance measurement. A detailed experiment is performed to investigate the regularity of the battery impedance in short-term relaxation time after switch-off current excitation, which indicates that the impedance can be measured and also has systematical decrement with the relaxation time growth. Based on the discussion of impedance variation in electrochemical perspective, as well as the monotonic relationship between impedance phase shift and battery internal temperature in the electrochemical equilibrium state, an exponential equation that accounts for both measured phase shift and relaxation time is established to correct the measuring deviation caused by electrochemical non-equilibrium. Then, a multivariate linear equation coupled with ambient temperature is derived considering the temperature gradients between the active part and battery surface. Equations stated above are all identified with the embedded thermocouple experimentally. In conclusion, the temperature estimation method can be a valuable alternative for temperature monitoring during cell operating, and serve the functionality as an efficient implementation in battery thermal management system for electric vehicles (EVs and hybrid electric vehicles (HEVs.

  5. MEMS-Based Boiler Operation from Low Temperature Heat Transfer and Thermal Scavenging

    Directory of Open Access Journals (Sweden)

    Leland Weiss

    2012-04-01

    Full Text Available Increasing world-wide energy use and growing population growth presents a critical need for enhanced energy efficiency and sustainability. One method to address this issue is via waste heat scavenging. In this approach, thermal energy that is normally expelled to the environment is transferred to a secondary device to produce useful power output. This paper investigates a novel MEMS-based boiler designed to operate as part of a small-scale energy scavenging system. For the first time, fabrication and operation of the boiler is presented. Boiler operation is based on capillary action that drives working fluid from surrounding reservoirs across a heated surface. Pressure is generated as working fluid transitions from liquid to vapor in an integrated steamdome. In a full system application, the steam can be made available to other MEMS-based devices to drive final power output. Capillary channels are formed from silicon substrates with 100 µm widths. Varying depths are studied that range from 57 to 170 µm. Operation of the boiler shows increasing flow-rates with increasing capillary channel depths. Maximum fluid mass transfer rates are 12.26 mg/s from 170 µm channels, an increase of 28% over 57 µm channel devices. Maximum pressures achieved during operation are 229 Pa.

  6. High efficiency,high power 808nm laser array and stacked arrays optimized for elevated temperature operation

    Institute of Scientific and Technical Information of China (English)

    Crump P A; Wise D; Crum T R; DeVito M; Farmer J; Grimshaw M; Huang Z; Igl S A; Macomber S; Thiagarajan P

    2004-01-01

    Operation of 808-nm laser diode pumping at elevated temperature is crucial to many applications. Reliable operation at high power is limited by high thermal load and low catastrophic optical mirror damage (COMD) threshold at elevated temperature range. We demonstrated high efficiency and high power operation at elevated temperature with high COMD power. These results were achieved through device design optimization such as growth conditions, doping profile, and materials composition of the quantum-well and other layers. Electrical-to-optical efficiency as high as 62% was obtained through lowered threshold current, lowered series resistance and increased slope efficiency. The performance of single broad-area laser diodes scales to that of high power single bars on water-cooled copper micro-channel heatsinks or conductively-cooled CS heatsinks. No reduction in bar performance or significant spectral broadening is seen when these micro-channel coolers are assembled into 6-bar and 18-bar CW stacks for the highest power levels.

  7. Performance and endurance of a high temperature PEM fuel cell operated on methanol reformate

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Grigoras, Ionela; Zhou, Fan

    2014-01-01

    This paper analyzes the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC) at varying temperatures, ranging from 140 °C to 180 °C. For the study, a H3PO4 – doped polybenzimidazole (PBI) – based membrane electrode assembly (MEA......) of 45 cm2 active surface area from BASF was employed. The study showed overall negligible effects of methanol-water vapor mixture slips on performance, even at relatively low simulated steam methanol reforming conversion of 90%, which corresponds to 3% methanol vapor by volume in the anode gas feed....... Temperature on the other hand has significant impact on the performance of an HT-PEMFC. To assess the effects of methanol-water vapor mixture alone, CO2 and CO are not considered in these tests. The analysis is based on polarization curves and impedance spectra registered for all the test points. After...

  8. The CO poisoning effect in PEMFCs operational at temperatures up to 200 degrees C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Gao, Ji-An;

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts (at a loading of 0.5 mg Pt/cm(2) per electrode! in polymer electrolyte membrane fuel cells (PEMFCs) has been investigated in a temperature range from 125 to 200 degreesC with the phosphoric acid-doped polybenzimidazole membranes...... as electrolyte. The effect is very temperature-dependent and can be sufficiently suppressed at elevated temperature. By defining the CO tolerance as a voltage loss less than 10 mV, it is evaluated that 3% CO in hydrogen can be tolerated at current densities up to 0.8 A/cm(2) at 200 degreesC, while at 125 degrees...

  9. Determination of the temperature-dependent cell membrane permeabilities using microfluidics with integrated flow and temperature control.

    Science.gov (United States)

    Fang, Cifeng; Ji, Fujun; Shu, Zhiquan; Gao, Dayong

    2017-02-28

    We developed an integrated microfluidic platform for instantaneous flow and localized temperature control. The platform consisted of a flow-focusing region for sample delivery and a cross-junction region embedded with a microheater for cell trapping and localized temperature control by using an active feedback control system. We further used it to measure the membrane transport properties of Jurkat cells, including the osmotically inactive cell volume (Vb) and cell membrane permeabilities to water (Lp) and to cryoprotective agent (CPA) solutions (dimethyl sulfoxide (DMSO) in this study) (PS) at various temperatures (room temperature, 30 °C, and 37 °C). Such characteristics of cells are of great importance in many applications, especially in optimal cryopreservation. With the results, the corresponding activation energy for water and CPA transport was calculated. The comparison of the results from the current study with reference data indicates that the developed platform is a reliable tool for temperature-dependent cell behavior study, which provides valuable tools for general cell manipulation applications with precise temperature control.

  10. Electrochemical Impedance Spectroscopy (EIS) Characterization of Reformate-operated High Temperature PEM Fuel Cell Stack

    DEFF Research Database (Denmark)

    Sahlin, Simon Lennart; Simon Araya, Samuel; Andreasen, Søren Juhl

    2017-01-01

    their effects on a reformate-operated stack. Polarization curves were also recorded to complement the impedance analysis of the researched phenomena. An equivalent circuit model was used to estimate the different resistances at varying parameters. It showed a significantly higher low frequency resistance...... at lower stoichiometry. Both anode and cathode stoichiometric ratios had significant effects on the stack performance during the dry hydrogen and reformate operation modes. In both cases the effects faded away when sufficient mass transport was achieved, which took place at λanode= 1.3 for dry hydrogen......, λanode= 1.6 for reformate operation and λcathode= 4.The work also compared dry hydrogen, steam reforming and autothermal reforming gas feeds at160 ◦Cand showed appreciably lower performance in the case of autothermal reforming at the same stoichiometry, mainly attributable to mass transport related...

  11. Numerical solution to the problem of variational assimilation of operational observational data on the ocean surface temperature

    Science.gov (United States)

    Agoshkov, V. I.; Lebedev, S. A.; Parmuzin, E. I.

    2009-02-01

    The problem of variational assimilation of satellite observational data on the ocean surface temperature is formulated and numerically investigated in order to reconstruct surface heat fluxes with the use of the global three-dimensional model of ocean hydrothermodynamics developed at the Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), and observational data close to the data actually observed in specified time intervals. The algorithms of the numerical solution to the problem are elaborated and substantiated, and the data assimilation block is developed and incorporated into the global three-dimensional model. Numerical experiments are carried out with the use of the Indian Ocean water area as an example. The data on the ocean surface temperature over the year 2000 are used as observational data. Numerical experiments confirm the theoretical conclusions obtained and demonstrate the expediency of combining the model with a block of assimilating operational observational data on the surface temperature.

  12. The influence of microstructure and operating temperature on the fatigue endurance of hot forged Inconel{sup ®} 718 components

    Energy Technology Data Exchange (ETDEWEB)

    Maderbacher, H., E-mail: hermann.maderbacher@unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Oberwinkler, B., E-mail: bernd.oberwinkler@bohler-forging.com [Böhler Schmiedetechnik GmbH and Co KG, Mariazellerstraße 25, 8605 Kapfenberg (Austria); Gänser, H.-P., E-mail: hans-peter.gaenser@mcl.at [Materials Center Leoben Forschung GmbH, Roseggerstraße 12, 8700 Leoben (Austria); Tan, W., E-mail: wen.tan@unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Rollett, M., E-mail: mathias.rollett@stud.unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Stoschka, M., E-mail: michael.stoschka@stud.unileoben.ac.at [Chair of Mechanical Engineering, Montanuniversität Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria)

    2013-11-15

    The dependence of the fatigue behavior of hot-forged Inconel{sup ®} 718 aircraft components on the operating temperature and the material microstructure is investigated. To this purpose, possible correlations between a variety of tested microstructural parameters and the results from low-cycle fatigue (LCF) testing are analyzed using statistical methods. To identify the prevailing damage mechanisms, failure analyses are carried out on specimens tested at different temperatures. Optical and scanning electron microscopy are used for the inspection of surface crack networks and of the final fracture surface. In addition, energy dispersive X-ray (EDX) analyses are performed at the crack initiation sites to track down possible accumulations of alloying elements. The results are critically reviewed and used to propose a temperature and microstructure dependent fatigue model for predicting LCF ε⧸N-curves.

  13. The electrolyte challenge for a direct methanol-air polymer electrolyte fuel cell operating at temperatures up to 200 C

    Science.gov (United States)

    Savinell, Robert; Yeager, Ernest; Tryk, Donald; Landau, Uziel; Wainright, Jesse; Gervasio, Dominic; Cahan, Boris; Litt, Morton; Rogers, Charles; Scherson, Daniel

    1993-01-01

    Novel polymer electrolytes are being evaluated for use in a direct methanol-air fuel cell operating at temperatures in excess of 100 C. The evaluation includes tests of thermal stability, ionic conductivity, and vapor transport characteristics. The preliminary results obtained to date indicate that a high temperature polymer electrolyte fuel cell is feasible. For example, Nafion 117 when equilibrated with phosphoric acid has a conductivity of at least 0.4 Omega(exp -1)cm(exp -1) at temperatures up to 200 C in the presence of 400 torr of water vapor and methanol vapor cross over equivalent to 1 mA/cm(exp 2) under a one atmosphere methanol pressure differential at 135 C. Novel polymers are also showing similar encouraging results. The flexibility to modify and optimize the properties by custom synthesis of these novel polymers presents an exciting opportunity to develop an efficient and compact methanol fuel cell.

  14. A SQUID based read-out of sub-attoNewton force sensor operating at millikelvin temperatures

    CERN Document Server

    Usenko, O; Wijts, G; Oosterkamp, T H

    2010-01-01

    An increasing number of experiments require the use of ultrasensitive nanomechanical resonators. Relevant examples are the investigation of quantum effects in mechanical systems [1] or the detection of exceedingly small forces as in Magnetic Resonance Force Microscopy (MRFM) [2]. The force sensitivity of a mechanical resonator is typically limited by thermal fluctuations, which calls for detection methods capable of operating at ultralow temperature. Commonly used interferometric techniques, despite their excellent sensitivity, may not be an optimal choice at millikelvin temperatures, because of unwanted resonator heating caused by photon absorption. Although alternative detection techniques based on microwave cavities [3] [4] [5] have shown to perform better at ultralow temperature, these techniques still suffer from the fact that the detection sensitivity decreases as the power input is decreased. Here, we present a measurement approach based on the detection, through a Superconducting Quantum Interference ...

  15. Operation, test, research and development of the high temperature engineering test reactor (HTTR). FY1999-2001

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-05-01

    The HTTR (High Temperature Engineering Test Reactor) with the thermal power of 30 MW and the reactor outlet coolant temperature of 850/950 degC is the first high temperature gas-cooled reactor (HTGR) in Japan, which uses coated fuel particle, graphite for core components, and helium gas for primary coolant. The HTTR, which locates at the south-west area of 50,000 m{sup 2} in the Oarai Research Establishment, had been constructed since 1991 before accomplishing the first criticality on November 10, 1998. Rise to power tests of the HTTR started in September, 1999 and the rated thermal power of 30 MW and the reactor outlet coolant temperature of 850 degC was attained in December 2001. JAERI received the certificate of pre-operation test, that is, the commissioning license for the HTTR in March 2002. This report summarizes operation, tests, maintenance, radiation control, and construction of components and facilities for the HTTR as well as R and Ds on HTGRs from FY1999 to 2001. (author)

  16. Quasiparticle injection effects in YBa2Cu3Ox-based planar structures at high operating temperatures

    NARCIS (Netherlands)

    Boguslavskij, Yu.M.; Joosse, K.; Sivakov, A.G.; Roesthuis, F.J.G.; Gerritsma, G.J.; Rogalla, H.

    1994-01-01

    The modulation of the supercurrent Is of a YBCO bridge by the quasiparticle-injection current IG from the YBCO/Au or YBCO/PBCO/Au junctions at temperatures of 60¿85 K is determined by two effects: (1) summation of the currents IS and IG in the YBCO bridge, and (2) nonequilibrium suppression of IS by

  17. Determination of the operating point and the enthalpy per unit surface of a cold battery with icy water and a double heat exchanger

    Directory of Open Access Journals (Sweden)

    B. Dieng1 ,

    2015-11-01

    Full Text Available The cold battery is a heat exchanger between two fluids, air (secondary fluid and iced water (primary fluid.The cold battery is composed of two heat exchangers in series, one of which is made up of flat-plate in galvanized steel serving as a reservoir for the iced water and the other one a copper shelland-tube exchanger with aluminum cooling blades. The two heat exchangers are connected to a pipe of the same diameter. These pipes will permit the transit of the icy water coming from the flat-plate heat exchanger by gravitation towards the tubes of the second exchanger [1]. The good operation of this cold battery depends on the knowledge of its operating point. We are proposing a technique of determination of the operating point by using one of the two fluids (water or air and the efficiencies [2, 3].The Knowledge of that operating point will enable us, through experimental means, determine the mean surface temperatureand then determine the mean surface enthalpy from the specific heat capacity at saturation obtained from the linearization of the entrance and exit air temperatures on the saturation curves.

  18. Effect of operating temperature on transient behaviour of a biofilter treating waste-air containing n-butanol vapour during intermittent loading.

    Science.gov (United States)

    Feizi, Farzaneh; Nasernejad, Bahram; Zamir, Seyed Morteza

    2016-01-01

    Transient-state removal of n-butanol vapour was investigated in a biofilter (BF) packed with compost and lava rock at different operating temperatures in the range of 30-45°C under intermittent loading (8 h per day). Adsorption on the inactive bed and biodegradation in the microbial-active bed were studied separately at an empty bed residence time (EBRT) of 1 min and inlet concentrations of 2.6-3.2 g m(-3), respectively. According to the transient experiments, the highest removal efficiency (RE) around 86% was obtained at 40°C due to a high microbial activity. Comparison of CO2 production and pure adsorption of n-butanol showed that adsorption was the major mechanism in the start-up of BF at each operating condition; although the impact of adsorption declined as temperature increased from 30°C to 45°C. The process was reaction limited at all operating conditions. Based on the determination of stoichiometric coefficients of n-butanol biodegradation, the CO2 production level was significantly lower than that of the chemical oxidation process which resulted in a decrease in environmental pollution.

  19. On-focal-plane superconducting signal processing for low- and intermediate-temperature operation

    Science.gov (United States)

    Smetana, Daryl L.; Carson, John C.

    1991-11-01

    The marriage of superconducting electronics with Z-plane FPA readout structures offer the potential for high speed, low power parallel digital processing on-focal plane. This paper reports on some early research into this marriage of two technologies conducted by Irvine Sensors Corporation (ISC) and TRW. Progress is reviewed for both low and high temperature superconducting technologies.

  20. CO tolerance by the PEMFC operational at temperatures up to 200°C

    DEFF Research Database (Denmark)

    Li, Qingfeng; He, Ronghuan; Gao, Ji-An;

    2003-01-01

    The CO poisoning effect on carbon-supported platinum catalysts in polymer electrolyte membrane fuel cells has been investigated in a temperature range from 125 to 200°C with the phosphoric acid-doped polybenzimidazole membranes as electrolyte. The effect is very temperature-dependent and can be s...... densities lower than 0.25 A/cm2. For comparison, the tolerance is only 0.0025 % CO (25 ppm) at 80°C at current densities up to 0.15 A/cm². The effect of CO2 in hydrogen was also studied. At 175°C, 25% CO2 in the fuel stream showed only the dilution effect.......The CO poisoning effect on carbon-supported platinum catalysts in polymer electrolyte membrane fuel cells has been investigated in a temperature range from 125 to 200°C with the phosphoric acid-doped polybenzimidazole membranes as electrolyte. The effect is very temperature-dependent and can...

  1. Operation experiences with a 30 kV/100 MVA high temperature superconducting cable system

    DEFF Research Database (Denmark)

    Tønnesen, Ole; Däumling, Manfred; Jensen, Kim Høj;

    2004-01-01

    of 1157 A. The operation experiences include over-currents of 6 kA due to faults on peripheral lines, commissioning, servicing and failure responses on the cooling system, continuous 24 h, 7 day per week monitoring and performance of the alarm system. The implications of these experiences for the future...

  2. Hazards Forecasting and Weights Determination during Operation and Maintenance of Petrol Fuel Station

    Directory of Open Access Journals (Sweden)

    M.M. Ahmed

    2013-06-01

    Full Text Available Petrol Fuel Stations (PFS is the most commonly available hazardous facility within urban and rural areas. Hazardous materials such as petrol, diesel, Compressed Natural Gas (CNG and kerosene oil normally sell and stores at PFS. PFS can be considered as small refinery within the city. A 3.5 year study conducted and 3216 non-compliances were recorded from PFS located in various cities of Pakistan. The operating company was ISO 14001 and OHSAS 18001 certified. The recorded non-compliances during study period were categorized into 8 potential factors. These were Housekeeping (HK, Transportation Hazard (TH, Slips, Trips and Falls (STF, Carelessness (C, Fire Risks (FR, Electrical Fault (EF, Miscellaneous Cases (MC and Medical Treatment Cases (MTC. Analytical Hierarchy Process (AHP was used and categorized 8 factors were prioritized. The same data was further classified based upon to cause fatality, accident, incident and near miss cases. A total numbers of 14, 426, 975 and 1804, fatality, accident, incident and near miss cases were recorded. With application of Exponential Smoothing method the fatalities, accident, incident and near miss cases for the years 2011, 2012 and 2013 were forecasted. The results of AHP and forecasted hazards will be presented and discussed in this study. It is hope that the both approaches will assist health and safety professionals for future hazards predictions and hazards weights determinations. Health and safety practitioners can take remedial and preventative measures by using past data with utilization of proposed techniques.

  3. Determination of the non-recrystallization temperature (TNR) in multiple microalloyed steels

    Science.gov (United States)

    Homsher, Caryn Nicole

    Rolling mill metallurgists must be able to easily and accurately determine critical temperatures such as the non-recrystallization temperature (T NR) to properly plan rolling schedules for desired properties. Microalloyed steels have small additions of alloying elements such as V, Ti, and Nb, to improve mechanical properties through grain size control and precipitation strengthening. The value of TNR is based on both alloying elements and deformation parameters. To easily predict TNR, equations have been developed and utilized in the literature and industry. However, each equation has certain limitations which constrain its applicability. This study was completed using ten laboratory grade low-carbon microalloyed steels designed to meet the API X-70 specification with varying amounts of V, Nb, and Ti. Double-hit deformation tests were conducted on a Gleeble® 3500 system in the standard pocket-jaw configuration at the Colorado School of Mines to determine experimental values of TNR. Double-hit deformation tests involve cylindrical specimens in an axisymmetric compression test. The test method requires six steps: 1) reheat to ensure most precipitates dissolve back into solution, 2) cool to deformation temperature, 3) compress with given strain and strain rate, 4) hold for interpass time, 5) deform specimen again holding everything else constant, and 6) measure the percent recrystallized or percent fractional softening. The TNR is the temperature where fractional softening is equal to 20 %. Niobium plays the largest role in influencing TNR. Complex niobium-vanadium-carbonitride precipitates are believed to play a significant role increasing TNR in the Hi-V alloy The experimental values of TNR were compared with predicted values of TNR from four equations in the literature. The Bai 2011 equation was the most reliable of the existing empirical formulas considered, while the commonly used Boratto equation was not accurate in predicting the TNR for the alloys in this

  4. Determination of equilibrium humidities using temperature and humidity controlled X-ray diffraction (RH-XRD)

    Energy Technology Data Exchange (ETDEWEB)

    Linnow, Kirsten [University of Hamburg, Department of Chemistry - Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany); Steiger, Michael [University of Hamburg, Department of Chemistry - Inorganic and Applied Chemistry, Martin-Luther-King-Platz 6, 20146 Hamburg (Germany)]. E-mail: michael.steiger@chemie.uni-hamburg.de

    2007-01-30

    Confined growth of crystals in porous building materials is generally considered to be a major cause of damage. We report on the use of X-ray diffraction under controlled conditions of temperature and relative humidity (RH-XRD) for the investigation of potentially deleterious phase transition reactions. An improved procedure based on rate measurements is used for the accurate and reproducible determination of equilibrium humidities of deliquescence and hydration reactions. The deliquescence humidities of NaCl (75.4 {+-} 0.5% RH) and Ca(NO{sub 3}){sub 2}.4H{sub 2}O (50.8 {+-} 0.7% RH) at 25 deg. C determined with this improved RH-XRD technique are in excellent agreement with available literature data. Measurement of the hydration of anhydrous Ca(NO{sub 3}){sub 2} to form Ca(NO{sub 3}){sub 2}.2H{sub 2}O revealed an equilibrium humidity of 10.2 {+-} 0.3%, which is also in reasonable agreement with available data. In conclusion, dynamic X-ray diffraction measurements are an appropriate method for the accurate and precise determination of equilibrium humidities with a number of interesting future applications.

  5. Performance of MWIR and SWIR HgCdTe-based focal plane arrays at high operating temperatures

    Science.gov (United States)

    Melkonian, Leon; Bangs, James; Elizondo, Lee; Ramey, Ron; Guerrero, Ernesto

    2010-04-01

    Raytheon Vision Systems (RVS) is producing large format, high definition HgCdTe-based MWIR and SWIR focal plane arrays (FPAs) with pitches of 15 μm and smaller for various applications. Infrared sensors fabricated from HgCdTe have several advantages when compared to those fabricated from other materials -- such as a highly tunable bandgap, high quantum efficiencies, and R0A approaching theoretical limits. It is desirable to operate infrared sensors at elevated operating temperatures in order to increase the cooler life and reduce the required system power. However, the sensitivity of many infrared sensors, including those made from HgCdTe, declines significantly above a certain temperature due to the noise resulting from increasing detector dark current. In this paper we provide performance data on a MWIR and a SWIR focal plane array operating at temperatures up to 160K and 170K, respectively. The FPAs used in the study were grown by molecular beam epitaxy (MBE) on silicon substrates, processed into a 1536x1024 format with a 15 μm pixel pitch, and hybridized to a silicon readout integrated circuit (ROIC) via indium bumps to form a sensor chip assembly (SCA). This data shows that the noise equivalent delta temperature (NEDT) is background limited at f/3.4 in the SWIR SCA (cutoff wavelength of 3.7 μm at 130K) up to 140K and in the MWIR SCA (cutoff wavelength of 4.8 μm at 115K) up to 115K.

  6. Single Temperature Liquefaction process at different operating pHs to improve ethanol production from Indian rice and corn feedstock.

    Science.gov (United States)

    Gohel, V; Ranganathan, K; Duan, G

    2016-10-13

    Conventional grain ethanol manufacturing is a high-temperature energy-intensive process comprising of multiple-unit operations when combined with lower ethanol recovery results in higher production cost. In liquefaction, jet cooking accounts for significant energy cost, while strong acid or base used for pH adjustment presents a safety hazard. A need is felt for sustainable ethanol manufacturing process that is less hazardous, consumes lower energy, and operates in a low pH range of 4.50-5.50. A single temperature liquefaction (STL) process that could efficiently operate at lower liquefaction temperature over a pH range of 4.50-5.50 was developed using rice and corn feedstock. Ethanol recovery witnessed at pH 4.5, 5.0, and 5.5 are 481.2 ± 1.5, 492.4 ± 1.5, and 493.6 ± 1.5 L MT(-1) rice, respectively. Similarly, ethanol recovery witnessed at pH 4.5, 5.0, and 5.5 are 404.6 ± 1.3, 413.9 ± 0.8, and 412.4 ± 1.8 L MT(-1) corn, respectively. The improvement in ethanol recovery is attributed to higher starch conversion by alpha-amylase even at pH as low as 4.50. Thus, the STL process operated at pH lower than 5.20 is poised to enhance sustainability by offering dual advantage of energy as well as chemical saving.

  7. Lifetime improvement of sheathed thermocouples for use in high-temperature and thermal operations

    Science.gov (United States)

    McCulloch, R. W.; Clift, J. H.

    Premature failure of small-diameter, magnesium-oxide-insulated sheathed thermocouples occurred when they were placed within nuclear fuel rod simulators to measure high temperatures and to follow severe thermal transients encountered during simulation of nuclear accidents in Oak Ridge National Laboratory thermal-hydraulic test facilities. Investigation of thermally cycled thermocouples yielded three criteria for improvement of thermocouple lifetime: (1) reduction of oxygen impurities prior to and during their fabrication; (2) refinement of thermoelement grain size during their fabrication; and (3) elimination of prestrain prior to use above their recrystallization temperature. The first and third criteria were satisfied by improved techniques of thermocouple assembly and by a recovery anneal prior to thermocouple use.

  8. A Method for more specific Simulation of Operative Temperature in Thermal Analysis Programmes

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik

    2008-01-01

    and the relative air velocity. However, in many programs the model for calculating the mean radiant temperature has traditionally been based on the calculation of an area weighted mean value independently of the location in the room. In practice the location of the person in the room has a significant influence...... and inhomogeneous radiation plays an important role for the usability and functionality of the room. In order to calculate the mean radiant temperature as function of the person´s location in the room one needs to calculate the angular factor between the person and the surfaces. The angular factor between surfaces...... can easily be calculated; however the angular factor between a person and a surface cannot be found directly from a formula, but needs to be approximated in order to be used in computer simulations. The paper describes different kinds of validations that have been done to compare different models...

  9. SNOW TEMPERATURE MEASUREMENTS AT VOSTOK STATION FROM AN AUTONOMOUS RECORDING SYSTEM (TAUTO: PRELIMINARY RESULTS FROM THE FIRST YEAR OPERATION

    Directory of Open Access Journals (Sweden)

    E. Lefebvre

    2012-01-01

    Full Text Available Temperature gradients in the upper layers of the snow pack are of importance for studying the emissivity properties of the snow surface with respect to microwaves used in remote sensing as well as for the heat and mass transfer in snow thickness. Gradients drive the initial snow microstructure metamorphisms that probably influence the firn properties in regard to air molecules fractionation and the air bubble enclosure process at close-off depths. As a contribution to investigation of these problems and following J.-M. Barnola initiative, we developed an autonomous recording system to monitor the temperature of the upper layers of the snow pack. The instrument was built to be autonomous and to be continuously operating within environmental conditions of the Antarctic plateau and the polar night. The apparatus which monitors temperature from the first 10 mof snow by 15 sensors of a «temperature grape» was set at Vostok station during 55th Russian Antarctic Expedition within the frame of the French Russian collaboration (GDRI Vostok. From the available hourly measurements over the first year, we present preliminary results on the thermal diffusive properties of the snow pack as well as some character of the temperature variations on the Antarctic plateau.

  10. Efficient ceramic anodes infiltrated with binary and ternary electrocatalysts for SOFCs operating at low temperatures

    DEFF Research Database (Denmark)

    Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei

    2012-01-01

    Electrocatalyst precursor of various combinations: Pt, Ru, Pd, Ni and Gd-doped CeO2 (CGO) were infiltrated into a porous Sr0.94Ti0.9Nb0.1O3 (STN) backbone, to study the electrode performance of infiltrated ceramic anodes at low temperature ranges of 400–600 °C. The performance of the binary elect...

  11. Effect of Temperature Variation and Gas Composition on the Stability of the RPC Operation

    CERN Document Server

    Cwiok, M; Górski, M; Królikowski, J

    2002-01-01

    An Inverted Double Gap RPC made of bakelite of 5*10^9 Ohm*cm volume resistivity was tested at avalanche rates up to 1 kHz/cm^2/gap in the Gamma Irradiation Facility at CERN in 2001. The inner surfaces of the chamber electrodes were cladded using linseed oil varnish. Dependence of the intrinsic RPC noise and the stability of the gas gain on the gas temperature and the gas composition are discussed.

  12. Characteristic features of the operation of high-temperature heat pipes with a noncondesable gas

    Science.gov (United States)

    Tolubinskiy, V. I.; Shevchuk, Ye. N.

    1987-01-01

    The principal concepts related to the nature of the processes occurring in high-temperature heat pipes with a noncondensable gas are examined, and guidelines for the development of such heat pipes are presented. The discussion is illustrated by experimental results obtained for a horizontal sodium heat pipe (diameter, 18/1 mm; length, 710 mm). In particular, attention is given to the starting dynamics and mechanisms, the shape of the vapor-gas front, and the vapor-gas front velocity.

  13. Temperature Control and Noise Reduction in our Compact ADR System for TES Microcalorimeter Operation

    Science.gov (United States)

    Hishi, U.; Fujimoto, R.; Kamiya, K.; Kotake, M.; Ito, H.; Kaido, T.; Tanaka, K.; Hattori, K.

    2016-08-01

    We have been developing a compact adiabatic demagnetization refrigerator, keeping ground application and future missions in mind. A salt pill fabricated in-house, a superconducting magnet with a passive magnetic shield around it, and a mechanical heat switch are mounted in a dedicated helium cryostat. The detector stage temperature is regulated by PID control of the magnet current, with a dI/dt term added to compensate the temperature rise due to parasitic heat. The temperature fluctuation of the detector stage is 1-2 \\upmu Krms, and the hold time was extended by about 15 % thanks to the dI/dt term. Bundle shields of the harnesses between the cryostat and the analog electronics boxes were connected to the chassis at both ends, and the analog electronics boxes were grounded to the cryostat through the bundle shields. This reduced the readout noise to 16 pA/√{Hz} in the 10-60 kHz range. Using this system, an energy resolution of 3.8 ± 0.2 eV (FWHM) was achieved at 5.9 keV.

  14. Increased operational temperature of Cr2O3-based spintronic devices

    Science.gov (United States)

    Street, Michael; Echtenkamp, Will; Komesu, Takashi; Cao, Shi; Wang, Jian; Dowben, Peter; Binek, Christian

    Spintronic devices have been considered a promising path to revolutionizing the current data storage and memory technologies. This work is an effort to utilize voltage-controlled boundary magnetization of the magnetoelectric chromia (Cr2O3) to be implemented into a spintronic device. The electric switchable boundary magnetization of chromia can be used to voltage-control the magnetic states of an adjacent ferromagnetic layer. For this technique to be utilized in a spintronic device, the antiferromagnetic ordering temperature of chromia must be enhanced above the bulk value of TN = 307K. Previously, based on first principle calculations, boron doped chromia thin films were fabricated via pulsed laser deposition showing boundary magnetization at elevated temperatures. Measurements of the boundary magnetization were also corroborated by spin polarized inverse photoemission spectroscopy. Exchange bias of B-doped chromia was also investigated using magneto-optical Kerr effect, showing an increased blocking temperature from 307K. Further boundary magnetization measurements and spin polarized inverse photoemission measurements indicate the surface magnetization to an in-plane orientation from the standard perpendicular orientation. This project was supported by the SRC through CNFD, an SRC-NRI Center under Task ID (2398.001) and by C-SPIN, part of STARnet, sponsored by MARCO and DARPA (No. SRC 2381.001).

  15. Temperature-dependent spectroscopy and microchip laser operation of Nd:KGd(WO4)2

    Science.gov (United States)

    Loiko, P.; Yoon, S. J.; Serres, J. M.; Mateos, X.; Beecher, S. J.; Birch, R. B.; Savitski, V. G.; Kemp, A. J.; Yumashev, K.; Griebner, U.; Petrov, V.; Aguiló, M.; Díaz, F.; Mackenzie, J. I.

    2016-08-01

    High-resolution absorption and stimulated-emission cross-section spectra are presented for monoclinic Nd:KGd(WO4)2 (Nd:KGW) laser crystals in the temperature range 77-450 K. At room-temperature, the maximum stimulated emission cross-section is σSE = 21.4 × 10-20 cm2 at 1067.3 nm, for light polarization E || Nm. The lifetime of the 4F3/2 state of Nd3+ in KGW is practically temperature independent at 115 ± 5 μs. Measurement of the energy transfer upconversion parameter for a 3 at.% Nd:KGW crystal proved that this was significantly smaller than for alternative hosts, ∼2.5 × 10-17 cm3/s. When cut along the Ng optical indicatrix axis, the Nd:KGW crystal was configured as a microchip laser, generating ∼4 W of continuous-wave output at 1067 nm with a slope efficiency of 61% under diode-pumping. Using a highly-doped (10 at.%) Nd:KGW crystal, the slope efficiency reached 71% and 74% when pumped with a laser diode and a Ti:Sapphire laser, respectively. The concept of an ultrathin (250 μm) Nd:KGW microchip laser sandwiched between two synthetic diamond heat-spreaders is demonstrated.

  16. [Determine and Implement Updates to Be Made to MODEAR (Mission Operations Data Enterprise Architecture Repository)

    Science.gov (United States)

    Fanourakis, Sofia

    2015-01-01

    My main project was to determine and implement updates to be made to MODEAR (Mission Operations Data Enterprise Architecture Repository) process definitions to be used for CST-100 (Crew Space Transportation-100) related missions. Emphasis was placed on the scheduling aspect of the processes. In addition, I was to complete other tasks as given. Some of the additional tasks were: to create pass-through command look-up tables for the flight controllers, finish one of the MDT (Mission Operations Directorate Display Tool) displays, gather data on what is included in the CST-100 public data, develop a VBA (Visual Basic for Applications) script to create a csv (Comma-Separated Values) file with specific information from spreadsheets containing command data, create a command script for the November MCC-ASIL (Mission Control Center-Avionics System Integration Laboratory) testing, and take notes for one of the TCVB (Terminal Configured Vehicle B-737) meetings. In order to make progress in my main project I scheduled meetings with the appropriate subject matter experts, prepared material for the meetings, and assisted in the discussions in order to understand the process or processes at hand. After such discussions I made updates to various MODEAR processes and process graphics. These meetings have resulted in significant updates to the processes that were discussed. In addition, the discussions have helped the departments responsible for these processes better understand the work ahead and provided material to help document how their products are created. I completed my other tasks utilizing resources available to me and, when necessary, consulting with the subject matter experts. Outputs resulting from my other tasks were: two completed and one partially completed pass through command look-up tables for the fight controllers, significant updates to one of the MDT displays, a spreadsheet containing data on what is included in the CST-100 public data, a tool to create a csv

  17. Porosity of UHPFRC exposed to high temperatures determined by different techniques

    Science.gov (United States)

    Korecký, Tomáš; Pokorný, Jaroslav; Fořt, Jan; Čítek, David; Pavlík, Zbyšek

    2016-07-01

    The pore system characterization of an Ultra High Performance Fibre Reinforced Concrete (UHPFRC) exposed to the elevated temperatures is presented in the paper. The porosity and pore size distribution of building materials are of the particular importance because of their clear effect on durability and service life of structural elements and buildings. Material characteristics as mechanical, thermal and hygric properties are strongly dependent on pore system. For porosity measurement, several techniques having specific advantages or disadvantages with respect to the pore size are available. In building materials research, usage of Mercury Intrusion Porosimetry (MIP) with range of the detected pores up to 100 µm is the most common. Nevertheless, in practical measurements, the differences between the porosity values determined by helium pycnometry and MIP are usually observed. It can be attributed to the presence of pores bigger than 100 µm. Based on the literature analysis it is evident that the porosity increases with the amount of fibres used since fibres application reduces workability of fresh mixture and thus cause heterogeneities and microcavities in material microstructure and interfacial transition zone between fibres, aggregates and cement paste. Therefore, the Optical Porosimetry (OP) based on an image analysis is presented in the paper as a suitable supplemental method for classification number, size and shape of bigger pores. At first, porosity is investigated on samples without temperature loading. Then, on samples which are exposed to the temperatures of 400, 800, and 1000 °C respectively. Pores size distribution is studied using mercury intrusion porosimeters Pascal 140 and 440. Images are captured by an optical microscope with an attached digital camera. The obtained results show necessity to apply the combined technique for the assessment of the porosity value.

  18. High temperature determines the ups and downs of small brown planthopper Laodelphax striatellus population

    Institute of Scientific and Technical Information of China (English)

    Xiang-Dong Liu; Ai-Min Zhang

    2013-01-01

    Small brown planthopper,Laodelphax striatellus (Fallén) numbers usually drop sharply in the summer and revive quickly in the autumn.However,it is unclear whether and how the high temperature plays a role in this process.The effects of durations of heat exposure (33℃) on life-history traits were examined here.Exposure of adults for 1 day during the oviposition stage led to a very low survival of nymphs.The average longevity ofL.striatellus exposed for 1-31 days from oviposition was significantly longer than that of the control (27℃).Short-term (1-5 days) heat exposure of the third instar nymphs did not significantly influence eclosion,but exposure of the fourth instar nymphs significantly increased eclosion.Lifespan from egg to adult was significantly lengthened when the third instar nymphs were exposed to heat for 2-15 days,or the fourth instar were exposed for 10 days.The preoviposition period was prolonged by heat exposure of the third or fourth instar nymphs.Short-term heat exposure of less than 3 days of the third or fourth instar nymphs did not restrict fecundity,but when the exposure duration exceeded 5 days the total eggs per female and hatchability decreased.Exposure to high temperature increased the brachypter rate of adults.In summary,low survival and slowing development under heat exposure resulted in population decline in the summer,and the relatively high fecundity and brachypter rate led to quick revival in autumn.Temperature in the summer determines the rise and fall in numbers of L.striatellus.

  19. High temperature oxidation behavior of AISI 304L stainless steel-Effect of surface working operations

    Science.gov (United States)

    Ghosh, Swati; Kumar, M. Kiran; Kain, Vivekanand

    2013-01-01

    The oxidation behavior of grade 304L stainless steel (SS) subjected to different surface finishing (machining and grinding) operations was followed in situ by contact electric resistance (CER) and electrochemical impedance spectroscopy (EIS) measurements using controlled distance electrochemistry (CDE) technique in high purity water (conductivity electrochemical properties and distinct morphological features of the oxide layer as a result of surface working were attributed to the prevalence of heavily fragmented grain structure and presence of martensite.

  20. Low temperature laser absorption spectra of methane in the near-infrared at 1.65 μm for lower state energy determination

    Institute of Scientific and Technical Information of China (English)

    Gao Wei; Chen Wei-Dong; Zhang Wei-Jun; Yuan Yi-Qian; Gao Xiao-Ming

    2012-01-01

    Direct absorption spectra of the 2v3 band of methane (CH4) from 6038 to 6050 cm-1 were studied at different low temperatures using a newly developed cryogenic cell in combination with a distributed feedback (DFB) diode laser.The cryogenic cell can operate at any stabilized temperature ranging from room temperature down to 100 K with temperature fluctuation less than ±l K within 1 hour.In the present work,the CH4 spectra in the range of 6038-6050 cm-1 were recorded at 296,266,248,223,198,and 176 K.The lower state energy E" and the rotational assignment of the angular momentum J were determined by a “2-low-temperature spectra method” using the spectra recorded at 198 and 176 K.The results were compared with the data from the GOSAT and the recently reported results from Campargue and co-workers using two spectra measured at room temperature and 81 K.We demonstrated that the use of a 2-low-temperature spectra method permits one to complete the E" and J values missed in the previous studies.