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Sample records for twelfth heat rate

  1. Radiative heating rates during AAOE and AASE

    Science.gov (United States)

    Rosenfield, Joan E.

    Radiative transit computations of heating rates utilizing data from the 1987 Airborne Antarctic Ozone Experiment (AAOE) (Tuck et al., 1989) and the 1989 Airborne Arctic Stratospheric Experiment (AASE) (Turco et al., 1990) are described. Observed temperature and ozone profiles and a radiative transfer model are used to compute the heating rates for the Southern Hemisphere during AAOE and the Northern Hemisphere during AASE. The AASE average cooling rates computed inside the vortex are in good agreement with the diabatic cooling rates estimated from the ER-2 profile data for N2O for the AASE period (Schoeberl et al., 1989).

  2. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  3. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  4. Research of heat exchange rate of the pulsating heat pipe

    Directory of Open Access Journals (Sweden)

    Kravets V. Yu.

    2010-02-01

    Full Text Available Given article presents experimental research of heat transfer characteristics of the pulsating heat pipe (PHP which consists of seven coils with 1 mm inner diameter. Water was used as the heat carrier. PHP construction, measuring circuit and research technique are presented. It is shown that under PHP functioning there are two characteristic modes of operation, which can be distinguished by values of thermal resistance. PHP heat exchange features are disclosed.

  5. Effect of heating rate on the pyrolysis yields of rapeseed

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S.; Kucukbayrak, S. [Chemical Engineering Department, Chemical and Metallurgical Engineering Faculty, Istanbul Technical University, Maslak, 34469 Istanbul (Turkey)

    2006-05-15

    The pyrolysis yields of rapeseed were investigated applying thermogravimetric analysis technique. The pyrolysis experiments were performed up to 1273K at heating rates of 5, 10, 20, 30, 40 and 50K/min in a dynamic nitrogen flow of 40cc/min. Effects of heating rate on the mass losses from the rapeseed were examined using the derivative thermogravimetric analysis profiles. This study showed that important differences on the pyrolytic behavior of rapeseed are observed when heating rate is changed. At the lower heating rates, the maximum rates of mass losses were relatively low. When the heating rate was increased, maximum rates of mass losses also increased. These variations were interpreted by the heterogeneous structure of biomass. Heating rates also concluded to affect the shape of the peaks. Increase in the heating rate shifted the main peak on the DTG profile to the lower temperatures. At low heating rates, there is probably resistance to mass or heat transfer inside the biomass particles. However, increase in heating rate overcame these restrictions, and led to higher conversion rates. The final pyrolysis temperatures were also affected from the variation of the heating rate. Activation energy values were first increased and then decreased depending on the heating rates. (author)

  6. Assessment of heating rate and non-uniform heating in domestic microwave ovens.

    Science.gov (United States)

    Pitchai, Krishnamoorthy; Birla, Sohan L; Jones, David; Subbiah, Jeyamkondan

    2012-01-01

    Due to the inherent nature of standing wave patterns of microwaves inside a domestic microwave oven cavity and varying dielectric properties of different food components, microwave heating produces non-uniform distribution of energy inside the food. Non-uniform heating is a major food safety concern in not-ready-to-eat (NRTE) microwaveable foods. In this study, we present a method for assessing heating rate and non-uniform heating in domestic microwave ovens. In this study a custom designed container was used to assess heating rate and non-uniform heating of a range of microwave ovens using a hedgehog of 30 T-type thermocouples. The mean and standard deviation of heating rate along the radial distance and sector of the container were measured and analyzed. The effect of the location of rings and sectors was analyzed using ANOVA to identify the best location for placing food on the turntable. The study suggested that the best location to place food in a microwave oven is not at the center but near the edge of the turntable assuming uniform heating is desired. The effect of rated power and cavity size on heating rate and non-uniform heating was also studied for a range of microwave ovens. As the rated power and cavity size increases, heating rate increases while non-uniform heating decreases. Sectors in the container also influenced heating rate (p heating rate. In general, sectors close to the magnetron tend to heat slightly faster than sectors away from the magnetron. However, the variation in heating rate among sectors was only 2 degrees C/min and considered not practically important. Overall heating performance such as mean heating rate and non-uniform heating did not significantly vary between the two replications that were performed 4 h apart. However, microwave ovens were inconsistent in producing the same heating patterns between the two replications that were performed 4 h apart.

  7. Twelfth degree spline with application to quadrature.

    Science.gov (United States)

    Mohammed, P O; Hamasalh, F K

    2016-01-01

    In this paper existence and uniqueness of twelfth degree spline is proved with application to quadrature. This formula is in the class of splines of degree 12 and continuity order [Formula: see text] that matches the derivatives up to order 6 at the knots of a uniform partition. Some mistakes in the literature are pointed out and corrected. Numerical examples are given to illustrate the applicability and efficiency of the new method.

  8. Bypass Flow Computations using a One-Twelfth Symmetric Sector For Normal Operation in a 350 MWth VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Richard W. Johnson; Hiroyuki Sato

    2010-10-01

    Significant uncertainty exists about the effects of bypass flow in a prismatic gas-cooled very high temperature reactor (VHTR). Bypass flow is the flow in the gaps between prismatic graphite blocks in the core. The gaps are present because of variations in their construction, imperfect installation and expansion and shrinkage from thermal heating and neutron fluence. Calculations are performed using computational fluid dynamics (CFD) for flow of the helium coolant in the gap and coolant channels along with conjugate heat generation and heat transfer in the fuel compacts and graphite. A commercial CFD code is used for all of the computations. A one-twelfth sector of a standard hexagonal block column is used for the CFD model because of its symmetry. Various scenarios are computed by varying the gap width from zero to 5 mm, varying the total heat generation rate to examine average and peak radial generation rates and variation of the graphite block geometry to account for the effects of shrinkage caused by irradiation. The calculations are for a 350 MWth prismatic reactor. It is shown that the effect of increasing gap width, while maintaining the same total mass flow rate, causes increased maximum fuel temperature while providing significant cooling to the near-gap region. The maximum outlet coolant temperature variation is increased by the presence of gap flow and also by an increase in total heat generation with a gap present. The effect of block shrinkage is actually to decrease maximum fuel temperature compared to a similar reference case.

  9. Bypass Flow Computations using a One-Twelfth Symmetric Sector For Normal Operation in a 350 MWth VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Richard W. Johnson; Hiroyuki Sato

    2012-10-01

    Significant uncertainty exists about the effects of bypass flow in a prismatic gas-cooled very high temperature reactor (VHTR). Bypass flow is the flow in the gaps between prismatic graphite blocks in the core. The gaps are present because of variations in their construction, imperfect installation and expansion and shrinkage from thermal heating and neutron fluence. Calculations are performed using computational fluid dynamics (CFD) for flow of the helium coolant in the gap and coolant channels along with conjugate heat generation and heat transfer in the fuel compacts and graphite. A commercial CFD code is used for all of the computations. A one-twelfth sector of a standard hexagonal block column is used for the CFD model because of its symmetry. Various scenarios are computed by varying the gap width from zero to 5 mm, varying the total heat generation rate to examine average and peak radial generation rates and variation of the graphite block geometry to account for the effects of shrinkage caused by irradiation. The calculations are for a 350 MWth prismatic reactor. It is shown that the effect of increasing gap width, while maintaining the same total mass flow rate, causes increased maximum fuel temperature while providing significant cooling to the near-gap region. The maximum outlet coolant temperature variation is increased by the presence of gap flow and also by an increase in total heat generation with a gap present. The effect of block shrinkage is actually to decrease maximum fuel temperature compared to a similar reference case.

  10. Heat exchangers selection, rating, and thermal design

    CERN Document Server

    Kakaç, Sadik; Pramuanjaroenkij, Anchasa

    2012-01-01

    Praise for the Bestselling Second EditionThe first edition of this work gathered in one place the essence of important information formerly scattered throughout the literature. The second edition adds the following new information: introductory material on heat transfer enhancement; an application of the Bell-Delaware method; new correlation for calculating heat transfer and friction coefficients for chevron-type plates; revision of many of the solved examples and the addition of several new ones.-MEMagazine

  11. HIGH HEATING RATES AFFECTS GREATLY THE INACTIVATION RATE OF ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Juan Pablo Huertas

    2016-08-01

    Full Text Available Heat resistance of microorganisms can be affected by different influencing factors. Although the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20ºC/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50ºC/min were achieved in the heat exchanger, which were much slower than those around 20ºC/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimates about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than ten times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7ºC/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing.

  12. High Heating Rates Affect Greatly the Inactivation Rate of Escherichia coli

    Science.gov (United States)

    Huertas, Juan-Pablo; Aznar, Arantxa; Esnoz, Arturo; Fernández, Pablo S.; Iguaz, Asunción; Periago, Paula M.; Palop, Alfredo

    2016-01-01

    Heat resistance of microorganisms can be affected by different influencing factors. Although, the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20°C/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50°C/min were achieved in the heat exchanger, which were much slower than those around 20°C/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimated about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than 10 times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7°C/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing. PMID:27563300

  13. Characteristic thermal constant and dimensionless heating rate. The links to optimum heating rate in GC

    Science.gov (United States)

    Blumberg; Klee

    2000-09-01

    An initial step in the quest of deriving a generalized approach to optimization of a temperature program in gas chromatography is presented. Central to this is the introduction of a dimensionless heating rate, r. As a first step to defining r, a characteristic thermal constant, thetachar, defined as thetachar = -dT/dk at k = 1, where T and k are, respectively, column temperature and solute retention factor, is introduced and evaluated for our own experimental data and for thermodynamic data from the literature. It was determined that, for silicone stationary phases with a phase ratio of 250, thetachar ranged from about 23 degrees C for low molecular weight hydrocarbons such as dimethylpropane to about 45 degrees C for high molecular weight pesticides such as mirex. It was also found that, for a particular solute and a stationary phase type, a 2 orders of magnitude increase in the film thickness caused only about a 2-fold increase in the characteristic thermal constant. Using thetachar as a fundamental temperature unit in GC and void time as a fundamental time unit, a dimensionless heating rate is introduced and its potential utility for the evaluation of the separation-speed tradeoffs in a temperature-programmed GC is demonstrated.

  14. Omani Twelfth Grade Students' Most Common Misconceptions in Chemistry

    Science.gov (United States)

    Al-Balushi, Sulaiman M.; Ambusaidi, Abdullah K.; Al-Shuaili, Ali H.; Taylor, Neil

    2012-01-01

    The current study, undertaken in the Sultanate of Oman, explored twelfth grade students' common misconceptions in seven chemistry conceptual areas. The sample included 786 twelfth grade students in Oman while the instrument was a two-tier test called Chemistry Misconceptions Diagnostic Test (CMDT), consisting of 25 items with 12 items…

  15. Studies on Microwave Heated Drying-rate Equations of Foods

    OpenAIRE

    1990-01-01

    In order to design various microwave heated drying apparatuses, we must take drying-rate equations which are based on simple drying-rate models. In a previous paper (KUBOTA, et al., 1990), we have studied a convenient microwave heated drying instrument, and studied the simple drying-rate equations of potato and so on by using the simple empirical rate equations that have been reported in previous papers (KUBOTA, 1979-1, 1979-2). In this paper, we studied the microwave drying rate of the const...

  16. Twelfth workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P.; Miller, F.G.; Horne, R.N.; Brigham, W.E.; Rivera, J. (Stanford Geothermal Program)

    1987-01-22

    Preface The Twelfth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 20-22, 1987. The year ending December 1986 was very difficult for the domestic geothermal industry. Low oil prices caused a sharp drop in geothermal steam prices. We expected to see some effect upon attendance at the Twelfth Workshop. To our surprise, the attendance was up by thirteen from previous years, with one hundred and fifty-seven registered participants. Eight foreign countries were represented: England, France, Iceland, Italy, Japan, Mexico, New Zealand, and Turkey. Despite a worldwide surplus of oil, international geothermal interest and development is growing at a remarkable pace. There were forty-one technical presentations at the Workshop. All of these are published as papers in this Proceedings volume. Seven technical papers not presented at the Workshop are also published; they concern geothermal developments and research in Iceland, Italy, and New Zealand. In addition to these forty-eight technical presentations or papers, the introductory address was given by Henry J. Ramey, Jr. from the Stanford Geothermal Program. The Workshop Banquet speaker was John R. Berg from the Department of Energy. We thank him for sharing with the Workshop participants his thoughts on the expectations of this agency in the role of alternative energy resources, specifically geothermal, within the country???s energy framework. His talk is represented as a paper in the back of this volume. The chairmen of the technical sessions made an important contribution to the workshop. Other than Stanford faculty members they included: M. Gulati, K. Goyal, G.S. Bodvarsson, A.S. Batchelor, H. Dykstra, M.J. Reed, A. Truesdell, J.S. Gudmundsson, and J.R. Counsil. The Workshop was organized by the Stanford Geothermal Program faculty, staff, and students. We would like to thank Jean Cook, Marilyn King, Amy Osugi, Terri Ramey, and Rosalee Benelli for their valued help with the meeting

  17. Twelfth Thermal and Fluids Analysis Workshop

    Science.gov (United States)

    Majumdar, Alok (Compiler)

    2002-01-01

    The Twelfth Thermal and Fluids Analysis Workshop (TFAWS 01) was held at the Bevill Center, The University of Alabama in Huntsville, Huntsville, Alabama, September 10-14, 2001. The theme for the hands-on training workshop and conference was "Engineering Excellence and Advances in the New Millenium." Forty-five technical papers were presented in four sessions: (1) Thermal Spacecraft/Payloads, (2) Thermal Propulsion/Vehicles, (3) Interdisciplinary Papers, and (4) Fluids Papers. Thirty-nine papers were published in these proceedings. The remaining six papers were not available in electronic format at the time of publication. In addition to the technical papers, there were (a) nine hands-on classes on thermal and flow analyses software, (b) thirteen short courses and product overview lectures, (c) five keynote lectures and, (d) panel discussions consisting of eight presentations. The workshop resulted in participation of 195 persons representing NASA Centers, Government agencies, aerospace industries, academia, software providers, and private corporations.

  18. Critical heat removal rate through a hemispherical narrow gap

    Energy Technology Data Exchange (ETDEWEB)

    Park, R.J.; Ha, K.S.; Kang, K.H.; Kim, S.B.; Kim, H.D. [Severe Accident Research Project, Korea Atomic Energy Research Institute Yusong, P.O. Box 105, Daejeon (Korea); Jeong, J.H. [Chonan College of Foreign Studies, An-seo-Wong 150, Chun-an (Korea)

    2003-02-01

    An experimental study has been performed to investigate boiling mechanism and to estimate critical heat removal rate from a critical power through a hemispherical narrow gap using distilled water and Freon R-113. The distilled water data on the critical heat removal rate were compared with the R-113 data. The experimental results on the critical heat removal rate were also compared with the existing correlations, developed in flat plate, annuli, and spherical gaps. The test results have shown that a CCFL (Counter Current Flow Limitation) brings about local dryout and finally global dryout in the hemispherical gap thickness of 0.5, 1.0, and 2.0 mm. The boiling mechanism in a hemispherical gap thickness of 5.0 mm is the combination of the CCFL and the pool boiling condition. An increase in gap thickness of 10.0 mm leads to the pool boiling condition rather than the CCFL. Increases in the gap thickness and pressure lead to increase in critical heat removal rate, but the pressure effect on the critical heat removal rate was found to be much milder than the predictions by flat plate and annuli gaps. The measured critical heat removal rate using the R-113 in hemispherical narrow gap thickness of 1.0 and 2.0 mm are 51.5%, 44.5% lower than that using the distilled water due to the lower boiling point and the bubble size, which is different from the pool boiling condition of approximately 14.8%. The measured critical heat removal rate using the R-113 in a gap thickness of 5 mm is 21.6% lower than that using distilled water, which approaches to the pool boiling condition. (orig.)

  19. “Textile Industry Twelfth Five Year Development Plan” issued

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Recently, the "Textile Industry Twelfth Five Year Development Plan" (hereinafter "Plan") has been issued by the Ministry of Industry and Information Technology, has been published to the public. The Plan highlights the restructuring, innovation, brand building

  20. Bypass flow computations using a one-twelfth symmetric sector for normal operation in a 350 MWth prismatic VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Richard W., E-mail: rich.johnson@inl.gov [Idaho National Laboratory, P.O. Box 1625, M.S. 3855, Idaho Falls, ID (United States); Sato, Hiroyuki, E-mail: sato.hiroyuki09@jaea.go.jp [Idaho National Laboratory, P.O. Box 1625, M.S. 3855, Idaho Falls, ID (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer CFD calculations are made of bypass flow between graphite blocks in VHTR. Black-Right-Pointing-Pointer Parameters varied include bypass gap width, heat generation and geometry. Black-Right-Pointing-Pointer Bypass flow causes lateral temperature gradients in graphite block. Black-Right-Pointing-Pointer Bypass flow causes increases in max fuel and coolant temperatures. Black-Right-Pointing-Pointer Bypass flow causes large increase in outlet coolant temperature variation - Abstract: Significant uncertainty exists about the effects of bypass flow in a prismatic gas-cooled very high temperature reactor (VHTR). Bypass flow is the flow in the gaps between prismatic graphite blocks in the core. The gaps are present because of variations in graphite block construction, imperfect installation and expansion and shrinkage from thermal heating and neutron fluence. Calculations are performed using computational fluid dynamics (CFD) for flow of the helium coolant in the gap and coolant channels along with conjugate heat generation and heat transfer in the fuel compacts and core graphite. A commercial CFD code is used for all of the computations. A one-twelfth sector of a standard hexagonal block column is used for the CFD model because of its symmetry. Various scenarios are investigated including varying the gap width, varying the total heat generation between average and peak rates and varying the graphite block geometry to account for the effects of shrinkage caused by irradiation. The calculations are for a 350 MWth prismatic reactor. It is shown that the effect of increasing gap width, while maintaining the same total mass flow rate, causes increased maximum fuel temperature while providing significant cooling to the near-gap region. The maximum outlet coolant temperature variation is increased by the presence of gap flow and also by an increase in total heat generation. The effect of block shrinkage is actually to decrease maximum

  1. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Lippuner, Jonas; Roberts, Luke F., E-mail: jlippuner@tapir.caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, MC 350-17, 1200 E California Boulevard, Pasadena CA 91125 (United States)

    2015-12-20

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y{sub e}, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y{sub e} ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y{sub e} lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y{sub e}, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y{sub e}, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

  2. Inverse bremsstrahlung heating rate for dense plasmas in laser fields

    Energy Technology Data Exchange (ETDEWEB)

    Dey, R. [D-203, Samruddhi Residency, Motera, Ahmedabad-380009, Gujarat (India); Roy, A. C. [School of Mathematical Sciences, Ramakrishna Mission Vivekananda University, Belur Math 711202, West Bengal (India)

    2013-07-15

    We report a theoretical analysis of inverse bremsstrahlung heating rate in the eikonal approximation. The present analysis is performed for a dense plasma using the screened electron-ion interaction potential for the ion charge state Z{sub i} = 1 and for both the weak and strong plasma screening cases. We have also compared the eikonal results with the first Born approximation (FBA) [M. Moll et al., New J. Phys. 14, 065010 (2012)] calculation. We find that the magnitudes of inverse bremsstrahlung heating rate within the eikonal approximation (EA) are larger than the FBA values in the weak screening case (κ = 0.03 a.u.) in a wide range of field strength for three different initial electron momenta (2, 3, and 4 a.u.). But for strong screening case (κ = 0.3 a.u.), the heating rates predicted by the two approximations do not differ much after reaching their maximum values. Furthermore, the individual contribution of photoemission and photoabsorption processes to heating rate is analysed for both the weak and strong screening cases. We find that the single photoemission and photoabsorption rates are the same throughout the field strength while the multiphoton absorption process dominates over the multiphoton emission process beyond the field strength ≈ 4×10{sup 8} V/cm. The present study of the dependence of heating rate on the screening parameter ranging from 0.01 to 20 shows that whereas the heating rate predicted by the EA is greater than the FBA up to the screening parameter κ = 0.3 a.u., the two approximation methods yield results which are nearly identical beyond the above value.

  3. Experimental Investigation of Heat transfer rate of Nano fluids using a Shell and Tube Heat exchanger

    Science.gov (United States)

    SIVA ESWARA RAO, M.; SREERAMULU, DOWLURU; ASIRI NAIDU, D.

    2016-09-01

    Nano fluids are used for increasing thermal properties in heat transfer equipment like heat exchangers, radiators etc. This paper investigates the heat transfer rate of Nano fluids using a shell and tube heat exchanger in single and multi tubes under turbulent flow condition by a forced convection mode. Alumina Nanoparticles are prepared by using Sol-Gel method. Heat transfer rate increases with decreasing particle size. In this experiment Alumina Nano particles of about 22 nm diameter used. Alumina Nano fluids are prepared with different concentrations of Alumina particles (0.13%, 0.27%, 0.4%, and 0.53%) with water as a base fluid using ultra-sonicator. Experiment have been conducted on shell and tube heat exchanger for the above concentrations on parallel and counter flow conditions by keeping constant inlet temperatures and mass flow rate. The result shows that the heat transfer rate is good compared to conventional fluids. The properties of Nano fluids and non-dimensional numbers have been calculated.

  4. EFFECT OF AIRFLOW AND HEAT INPUT RATES ON DUCT EFFICIENCY.

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    2003-05-28

    Reducing the airflow and heat input rates of a furnace that is connected to a duct system in thermal contact with unconditioned spaces can significantly reduce thermal distribution efficiency. This is a straightforward theoretical calculation based on the increased residence time of the air in the duct at the lower flow rate, which results in greater conduction losses. Experimental tests in an instrumented residential-size duct system have confirmed this prediction. Results are compared with the heat-loss algorithm in ASHRAE Standid 152P. The paper concludes with a discussion of possible remedies for this loss of efficiency in existing systems and optional design strategies in new construction.

  5. HEATING RATE SCALING OF TURBULENCE IN THE PROTON KINETIC REGIME

    Energy Technology Data Exchange (ETDEWEB)

    Vasquez, Bernard J., E-mail: bernie.vasquez@unh.edu [Physics Department and Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)

    2015-06-10

    Three-dimensional numerical hybrid simulations with particle protons and quasi-neutralizing, fluid electrons are conducted for a freely decaying turbulence. The main results are obtained from a series of runs as a function of the initial total rms fluctuation amplitude. In the turbulent phase and at a corresponding nonlinear time dependent on the amplitude, the scaling of the proton perpendicular heating rate is examined as a function of the spectral value of the electron bulk perpendicular speed integrated in wavenumbers about the inverse thermal proton gyroradius. The perpendicular direction is relative to the background magnetic field. The obtained spectral value is normalized to the proton thermal speed and ranges from 0.06 to 0.16. The scaling of the perpendicular heating rate with this spectral value is fitted with a power law, which has an index of −3.3 ± 0.2. The fit is consistent with the scaling of the total heating rate as a function of total rms amplitude, which has an index of −3.06 ± 0.12. The power-law index is near the turbulent hydrodynamic-like prediction for the energy cascade rate as a function of amplitude. The heating rate, then, obeys a power law with amplitude or spectral value regardless of whether that quantity is evaluated at large scales or at the proton gyroradius scales.

  6. Heating rate dependence of anatase to rutile transformation

    Directory of Open Access Journals (Sweden)

    Pietro Galizia

    2016-12-01

    Full Text Available Commercial titania powders were calcined in order to investigate the influence of the heating history on the thermally stable phase (rutile. Temperatures from 620 to 700 °C and heating rates from 50 to 300 °C/h were used in order to evaluate their influence on the kinetics of transformation and microstructure evolution. The quantitative analysis of anatase-rutile mixtures based on X-ray diffraction intensities was performed. The results were plotted as cumulative transformation rate vs. cumulative coarsening rate in order to address the heating history of the anatase to rutile transformation. As the main result it was found that the amount of anatase transformed into rutile increases with increasing heating rate at fixed soaking time and temperature of calcination. Through linear extrapolation of experimental data obtained from the calcined commercial titania Degussa P25, it was found that 83 nm for the rutile crystallite size is the lowest limit needed for getting 100% of rutile powders. A substantial improvement in the anatase to rutile kinetic transformation was achieved after pressing the starting powders in order to exploit the interface nucleation.

  7. Flash Heating of Crustal Rocks at Seismic Slip Rates

    Science.gov (United States)

    Goldsby, D. L.; Spagnuolo, E.; Smith, S. A.; Beeler, N. M.; Tullis, T. E.; Di Toro, G.; Nielsen, S. B.

    2012-12-01

    Recent experiments have demonstrated that rocks undergo extreme frictional weakening at near-earthquake slip rates due to the thermal degradation of the strength, or even melting, of microscopic asperity contacts on their sliding surfaces (Goldsby and Tullis, 2012). These previous experiments, conducted at constant normal stress and slip rates of up to ~0.4 m/s, revealed a 1/V dependence of friction on slip rate above a characteristic weakening velocity, Vw, in accord with theories of flash heating (e.g., Rice, 2006). The weakening velocity obtains values of ~0.1 m/s for many crustal silicate rocks (Goldsby and Tullis, 2012). Here we test two further predictions of flash-heating theory - that the degree of weakening saturates at slip rates approaching 1 m/s, and that the weakening behavior due to flash heating is independent of normal stress - by testing samples at slip rates of up to 1 m/s at different normal stresses. Experiments were conducted in a 1-atm, high-velocity friction apparatus at the Istituto Nazionale di Geofisica e Vulcanologia in Rome. A sample consisted of a pair of hollow cylinders of Westerly granite or Frederick diabase subjected to a nominally constant normal stress of from 1 to 30 MPa and subjected to a variety of rate-stepping sequences. Data were acquired at rates of up to 1 MHz. As predicted, the experiments demonstrate that the degree of weakening due to flash heating saturates at slip rates approaching 1 m/s; in a few cases, friction even increases slightly with increasing slip rate near 1 m/s. The experiments also demonstrate that, within the scatter of the data, the value of Vw and the friction coefficient in the weakened state is independent of normal stress, the expected result if average contact sizes and contact stresses are independent of normal stress. The data thus further corroborate existing theories and experimental data for flash heating, allowing for a more reliable determination of the conditions under which flash heating

  8. Three-dimensional transient mathematical model to predict the heat transfer rate of a heat pipe

    Directory of Open Access Journals (Sweden)

    S Boothaisong

    2015-02-01

    Full Text Available A three-dimensional model was developed to simulate the heat transfer rate on a heat pipe in a transient condition. This article presents the details of a calculation domain consisting of a wall, a wick, and a vapor core. The governing equation based on the shape of the pipe was numerically simulated using the finite element method. The developed three-dimensional model attempted to predict the transient temperature, the velocity, and the heat transfer rate profiles at any domain. The values obtained from the model calculation were then compared with the actual results from the experiments. The experiment showed that the time required to attain a steady state (where transient temperature is constant was reasonably consistent with the model. The working fluid r134a (tetrafluoroethane was the quickest to reach the steady state and transferred the greatest amount of heat.

  9. r-Process Lanthanide Production and Heating Rates in Kilonovae

    CERN Document Server

    Lippuner, Jonas

    2015-01-01

    r-Process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the material after nuclear burning ceases, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. (2013, ApJ, 774, 25) and Tanaka & Hotokezaka (2013, ApJ, 775, 113) pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions $Y_e$, initial specific entropies $s$, and expansion timescales $\\tau$. We find that the ejecta is lanthanide-free for $Y_e \\gtrsim 0.22 - 0.30$, depending on $s$ and $\\tau$. The heating rate is insensitive to $s$ and $\\tau$, but certain, larger values of $Y_e$ lead to reduced heating rates, due to individual nuclides dominating the heating. With a...

  10. Standby Rates for Combined Heat and Power Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sedano, Richard [Regulatory Assistance Partnership; Selecky, James [Brubaker & Associates, Inc.; Iverson, Kathryn [Brubaker & Associates, Inc.; Al-Jabir, Ali [Brubaker & Associates, Inc.

    2014-02-01

    Improvements in technology, low natural gas prices, and more flexible and positive attitudes in government and utilities are making distributed generation more viable. With more distributed generation, notably combined heat and power, comes an increase in the importance of standby rates, the cost of services utilities provide when customer generation is not operating or is insufficient to meet full load. This work looks at existing utility standby tariffs in five states. It uses these existing rates and terms to showcase practices that demonstrate a sound application of regulatory principles and ones that do not. The paper also addresses areas for improvement in standby rates.

  11. Resistive Wall Heating of the Undulator in High Repetition Rate

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, J; Corlett, J; Emma, P; Wu, J

    2012-05-20

    In next generation high repetition rate FELs, beam energy loss due to resistive wall wakefields will produce significant amount of heat. The heat load for a superconducting undulator (operating at low temperature), must be removed and will be expensive to remove. In this paper, we study this effect in an undulator proposed for a Next Generation Light Source (NGLS) at LBNL. We benchmark our calculations with measurements at the LCLS and carry out detailed parameter studies using beam from a start-to-end simulation. Our preliminarym results suggest that the heat load in the undulator is about 2 W/m or lower with an aperture size of 6 mm for nominal NGLS preliminary design parameters.

  12. Heat transfer and heating rate of food stuffs in commercial shop ovens

    Indian Academy of Sciences (India)

    P Navaneethakrishnan; P S S Srinivasan; S Dhandapani

    2007-10-01

    The CFD analysis of flow and temperature distribution in heating ovens used in bakery shop, to keep the foodstuffs warm, is attempted using finite element technique. The oven is modelled as a two-dimensional steady state natural convection heat transfer problem. Effects of heater location and total heat input on temperature uniformity of foodstuffs are studied. Placing the heater at the bottom of the oven improves the air circulation rate by 17 times and 10 times than that at the top and side of the oven. But the top location provides better uniformity in foodstuff temperature than the other cases. Side location is not preferable. In the present ovens, the heating elements are located at the top. The analysis shows that if heaters are located at the bottom along with additional flow guidance arrangements, energy efficient oven configuration can be obtained.

  13. Pyrolysis kinetics of bagasse at high heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Stubington, J.F.; Aiman, S. (University of New South Wales, Kensington, NSW (Australia). Dept. of Fuel Technology)

    The rate of pyrolysis of bagasse was studied at high heating rates (200-10,000 [degree]C/s) to obtain engineering data for incorporation into computational fluid dynamic models of bagasse ignition and combustion in suspension-fired and swirl burners. Experiments were performed using an electrically-heated grid under a nitrogen atmosphere at atmosphere pressure. Yields of char, tar, individual gas components, and water were measured as a function of peak temperature, for ranges of heating rate, residence time at peak temperature, and particle size. At higher peak temperatures, significant tar cracking occurred so that tar yields passed through a maximum as peak temperature increased. For dry bagasse, this tar cracking produced gases with no change in char yield, suggesting that it occurred external to the particle. Moisture in the atmosphere increased the tar cracking in the vapor phase outside the bagasse particle producing more gases but did not affect the char yield. However, moisture in the bagasse reduced the char yield and further enhanced the tar cracking reactions, producing even more gases (predominantly carbon monoxide). These results suggested an interaction between water vapor and the tar cracking reactions. For the short residence times appropriate to such burners, a single, first-order reaction model gave the best fit to the total weight loss for the ranges of heating rate and particle sizes studied. However, the first-order kinetic parameters fitted to primary tar production were recommended for modeling purposes because the total weight loss included significant yields of noncombustible water and carbon dioxide. Different ultimate primary tar yields were recommended to fit the dry and wet bagasse pyrolysis results. No chemical significance should be attributed to the kinetic parameters, which were determined to provide the simplest and best fit to the pyrolysis data. 19 refs., 15 figs., 5 tabs.

  14. Particle loading rates for HVAC filters, heat exchangers, and ducts.

    Science.gov (United States)

    Waring, M S; Siegel, J A

    2008-06-01

    The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

  15. Analysis of Water Recovery Rate from the Heat Melt Compactor

    Science.gov (United States)

    Balasubramaniam, R.; Hegde, U.; Gokoglu, S.

    2013-01-01

    any remaining free water in the trash by evaporation. The temperature settings of the heated surfaces are usually kept above the saturation temperature of water but below the melting temperature of the plastic in the waste during this step to avoid any encapsulation of wet trash which would reduce the amount of recovered water by blocking the vapor escape. In this paper, we analyze the water recovery rate during Phase B where the trash is heated and water leaves the waste chamber as vapor, for operation of the HMC in reduced gravity. We pursue a quasi-one-dimensional model with and without sidewall heating to determine the water recovery rate and the trash drying time. The influences of the trash thermal properties, the amount of water loading, and the distribution of the water in the trash on the water recovery rates are determined.

  16. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  17. Maximum orbit plane change with heat-transfer-rate considerations

    Science.gov (United States)

    Lee, J. Y.; Hull, D. G.

    1990-01-01

    Two aerodynamic maneuvers are considered for maximizing the plane change of a circular orbit: gliding flight with a maximum thrust segment to regain lost energy (aeroglide) and constant altitude cruise with the thrust being used to cancel the drag and maintain a high energy level (aerocruise). In both cases, the stagnation heating rate is limited. For aeroglide, the controls are the angle of attack, the bank angle, the time at which the burn begins, and the length of the burn. For aerocruise, the maneuver is divided into three segments: descent, cruise, and ascent. During descent the thrust is zero, and the controls are the angle of attack and the bank angle. During cruise, the only control is the assumed-constant angle of attack. During ascent, a maximum thrust segment is used to restore lost energy, and the controls are the angle of attack and bank angle. The optimization problems are solved with a nonlinear programming code known as GRG2. Numerical results for the Maneuverable Re-entry Research Vehicle with a heating-rate limit of 100 Btu/ft(2)-s show that aerocruise gives a maximum plane change of 2 deg, which is only 1 deg larger than that of aeroglide. On the other hand, even though aerocruise requires two thrust levels, the cruise characteristics of constant altitude, velocity, thrust, and angle of attack are easy to control.

  18. The pyrolysis kinetics of bagasse at low heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Aiman, S.; Stubington, J.F. (New South Wales Univ., Kensington, NSW (Australia))

    1993-01-01

    Thermogravimetric Analysis (TGA) was used to study the thermal degradation of wet and dry bagasse at low heating rates (5 to 50[sup o]C min[sup -1]) under a nitrogen atmosphere. For engineering purposes, it was found that a single first-order reaction gave the simplest and best fit to the rapid pyrolysis zone between 195 and 395[sup o]C, with an activation energy of 93.2 kJ mol[sup -1] and pre-exponential factor of 4.33 x 10[sup 4]s[sup -1]. These values have no chemical significance, but have been derived for use in modelling studies of the ignition and combustion of bagasse. Sample moisture content up to 18% by weight had no effect on the degradation, because moisture evaporation was complete before pyrolysis commenced at these low heating rates. The choice of the final mass from the TGA curve significantly affected the deduced kinetic parameters. The final sample mass at the end of the rapid pyrolysis zone was 26.2% of the dry sample mass. (author)

  19. Integration and software for thermal test of heat rate sensors

    Science.gov (United States)

    Wojciechowski, C. J.; Shrider, K. R.

    1982-04-01

    A minicomputer controlled radiant test facility is described which was developed and calibrated in an effort to verify analytical thermal models of instrumentation islands installed aboard the space shuttle external tank to measure thermal flight parameters during ascent. Software was provided for the facility as well as for development tests on the SRB actuator tail stock. Additional testing was conducted with the test facility to determine the temperature and heat flux rate and loads required to effect a change of color in the ET tank external paint. This requirement resulted from the review of photographs taken of the ET at separation from the orbiter which showed that 75% of the external tank paint coating had not changed color from its original white color. The paint on the remaining 25% of the tank was either brown or black, indicating that it had degraded due to heating or that the spray on form insulation had receded in these areas. The operational capability of the facility as well as the various tests which were conducted and their results are discussed.

  20. Twelfth night of 1917 and the Moscow art theatre Twelfth night of 1917 and the Moscow art theatre

    Directory of Open Access Journals (Sweden)

    Arkady Ostrovsky

    2008-04-01

    Full Text Available On 15 September, 1917, in a letter to Nemirovich-Danchenko, Stanislavsky renounced the stage of the Moscow Art Theatre: I cannot think about any other roles, because I will never be able to do anything, at least in the Moscow Art Theatre. Maybe in some other area or some other place I will be able to rise. Of course I do not mean in other theatres, but in the studios. Othello — free!...1 After the tragedy Stanislavsky had endured with Selo Stepanchikovo, he threw himself into Studio work. He started rehearsing Twelfth Night, a play he had put on at the Society of Art and Literature in 1897. The Studio production of Twelfth Night was played on 25 December 1917, two months to the day after the Revolution. A few months later, Nikolai Efros published a book about the First Studio. It was dedicated to The Cricket on the Hearth but the words Efros used to describe the atmosphere in which Dickens’s production had opened were equally suitable for Twelfth Night: ‘You remember what sort of days those were? On 15 September, 1917, in a letter to Nemirovich-Danchenko, Stanislavsky renounced the stage of the Moscow Art Theatre: I cannot think about any other roles, because I will never be able to do anything, at least in the Moscow Art Theatre. Maybe in some other area or some other place I will be able to rise. Of course I do not mean in other theatres, but in the studios. Othello — free!...1 After the tragedy Stanislavsky had endured with Selo Stepanchikovo, he threw himself into Studio work. He started rehearsing Twelfth Night, a play he had put on at the Society of Art and Literature in 1897. The Studio production of Twelfth Night was played on 25 December 1917, two months to the day after the Revolution. A few months later, Nikolai Efros published a book about the First Studio. It was dedicated to The Cricket on the Hearth but the words Efros used to describe the atmosphere in which Dickens’s production had opened

  1. The Optimum Plate to Plate Spacing for Maximum Heat Transfer Rate from a Flat Plate Type Heat Exchanger

    Science.gov (United States)

    Ambarita, Himsar; Kishinami, Koki; Daimaruya, Mashashi; Tokura, Ikuo; Kawai, Hideki; Suzuki, Jun; Kobiyama, Mashayosi; Ginting, Armansyah

    The present paper is a study on the optimum plate to plate spacing for maximum heat transfer rate from a flat plate type heat exchanger. The heat exchanger consists of a number of parallel flat plates. The working fluids are flowed at the same operational conditions, either fixed pressure head or fixed fan power input. Parallel and counter flow directions of the working fluids were considered. While the volume of the heat exchanger is kept constant, plate number was varied. Hence, the spacing between plates as well as heat transfer rate will vary and there exists a maximum heat transfer rate. The objective of this paper is to seek the optimum plate to plate spacing for maximum heat transfer rate. In order to solve the problem, analytical and numerical solutions have been carried out. In the analytical solution, the correlations of the optimum plate to plate spacing as a function of the non-dimensional parameters were developed. Furthermore, the numerical simulation is carried out to evaluate the correlations. The results show that the optimum plate to plate spacing for a counter flow heat exchanger is smaller than parallel flow ones. On the other hand, the maximum heat transfer rate for a counter flow heat exchanger is bigger than parallel flow ones.

  2. Research of Heating Rates Influence on Layer Coal Gasification of Krasnogorsky And Borodinsky Coal Deposit

    Directory of Open Access Journals (Sweden)

    Jankovskiy Stanislav

    2015-01-01

    Full Text Available Experimental research of heating rate influence on coal samples gasification process of Krasnogorsky and Borodinsky coal deposit ranks A and 2B was done to define optimal heating mode in high intensification of dispersal of inflammable gases conditions. Abundance ratio of carbon monoxide and nitrogen monoxide, water vapor, carbon dioxide at four values of heating rate within the range of 5 to 30 K/min. with further definition of optimal heating rate of coals was stated.

  3. Dissolution and Precipitation Behaviour during Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating Rates

    Directory of Open Access Journals (Sweden)

    Julia Osten

    2015-05-01

    Full Text Available In the present study, the dissolution and precipitation behaviour of four different aluminium alloys (EN AW-6005A, EN AW-6082, EN AW-6016, and EN AW-6181 in four different initial heat treatment conditions (T4, T6, overaged, and soft annealed was investigated during heating in a wide dynamic range. Differential scanning calorimetry (DSC was used to record heating curves between 20 and 600 °C. Heating rates were studied from 0.01 K/s to 5 K/s. We paid particular attention to control baseline stability, generating flat baselines and allowing accurate quantitative evaluation of the resulting DSC curves. As the heating rate increases, the individual dissolution and precipitation reactions shift to higher temperatures. The reactions during heating are significantly superimposed and partially run simultaneously. In addition, precipitation and dissolution reactions are increasingly suppressed as the heating rate increases, whereby exothermic precipitation reactions are suppressed earlier than endothermic dissolution reactions. Integrating the heating curves allowed the enthalpy levels of the different initial microstructural conditions to be quantified. Referring to time–temperature–austenitisation diagrams for steels, continuous heating dissolution diagrams for aluminium alloys were constructed to summarise the results in graphical form. These diagrams may support process optimisation in heat treatment shops.

  4. 40 CFR 75.36 - Missing data procedures for heat input rate determinations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Missing data procedures for heat input... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Missing Data Substitution Procedures § 75.36 Missing data procedures for heat input rate determinations. (a) When hourly heat input rate...

  5. Heat transfer intensification by increasing vapor flow rate in flat heat pipes

    Science.gov (United States)

    Sprinceana, Silviu; Mihai, Ioan; Beniuga, Marius; Suciu, Cornel

    2015-02-01

    Flat heat pipes have various technical applications, one of the most important being the cooling of electronic components[9]. Their continuous development is due to the fact that these devices permit heat transfer without external energetic contribution. The practical exploitation of flat heat pipes however is limited by the fact that dissipated power can only reach a few hundred watts. The present paper aims to advance a new method for the intensification of convective heat transfer. A centrifugal mini impeller, driven by a turntable which incorporates four permanent magnets was designed. These magnets are put in motion by another rotor, which in its turn includes two permanent magnets and is driven by a mini electrical motor. Rotation of the centrifugal blades generates speed and pressure increase of the cooling agent brought to vapor state within the flat micro heat pipe. It's well known that the liquid suffers biphasic transformations during heat transfer inside the heat pipe. Over the hotspot (the heat source being the electronic component) generated at one end of the heat pipe, convective heat transfer occurs, leading to sudden vaporization of the liquid. Pressures generated by newly formed vapors push them towards the opposite end of the flat heat pipe, where a finned mini heat sink is usually placed. The mini-heat exchanger is air-cooled, thus creating a cold spot, where vapors condensate. The proposed method contributes to vapor flow intensification by increasing their transport speed and thus leading to more intense cooling of the heat pipe.

  6. An algorithm for the kinetics of tire pyrolysis under different heating rates.

    Science.gov (United States)

    Quek, Augustine; Balasubramanian, Rajashekhar

    2009-07-15

    Tires exhibit different kinetic behaviors when pyrolyzed under different heating rates. A new algorithm has been developed to investigate pyrolysis behavior of scrap tires. The algorithm includes heat and mass transfer equations to account for the different extents of thermal lag as the tire is heated at different heating rates. The algorithm uses an iterative approach to fit model equations to experimental data to obtain quantitative values of kinetic parameters. These parameters describe the pyrolysis process well, with good agreement (r(2)>0.96) between the model and experimental data when the model is applied to three different brands of automobile tires heated under five different heating rates in a pure nitrogen atmosphere. The model agrees with other researchers' results that frequencies factors increased and time constants decreased with increasing heating rates. The model also shows the change in the behavior of individual tire components when the heating rates are increased above 30 K min(-1). This result indicates that heating rates, rather than temperature, can significantly affect pyrolysis reactions. This algorithm is simple in structure and yet accurate in describing tire pyrolysis under a wide range of heating rates (10-50 K min(-1)). It improves our understanding of the tire pyrolysis process by showing the relationship between the heating rate and the many components in a tire that depolymerize as parallel reactions.

  7. Effect of Heating Rate on Glass Foaming: Transition to Bulk Foam

    Energy Technology Data Exchange (ETDEWEB)

    Hrma, Pavel R.

    2009-02-15

    Foaming of glass is an undesirable side effect of glass fining. According to a recent experimental study, the gas-phase volume in the melt heated at a constant rate dramatically increased with an increased rate of heating. This observation indicates that an increased rate of heating (a natural consequence of the increased processing rate experienced as a result of transition to oxy-fuel firing) may exert a substantial influence on glass foaming in advanced glass-melting furnaces. This paper attributes this effect to the change of mode of foam formation in response to an increased rate of heating.

  8. Heat storage rate and acute fatigue in rats

    Directory of Open Access Journals (Sweden)

    L.O.C. Rodrigues

    2003-01-01

    Full Text Available Thermal environmental stress can anticipate acute fatigue during exercise at a fixed intensity (%VO2max. Controversy exists about whether this anticipation is caused by the absolute internal temperature (Tint, ºC, by the heat storage rate (HSR, cal/min or by both mechanisms. The aim of the present study was to study acute fatigue (total exercise time, TET during thermal stress by determining Tint and HSR from abdominal temperature. Thermal environmental stress was controlled in an environmental chamber and determined as wet bulb globe temperature (ºC, with three environmental temperatures being studied: cold (18ºC, thermoneutral (23.1ºC or hot (29.4ºC. Six untrained male Wistar rats weighing 260-360 g were used. The animals were submitted to exercise at the same time of day in the three environments and at two treadmill velocities (21 and 24 m/min until exhaustion. After implantation of a temperature sensor and treadmill adaptation, the animals were submitted to a Latin square experimental design using a 2 x 3 factorial scheme (velocity and environment, with the level of significance set at P<0.05. The results showed that the higher the velocity and the ambient temperature, the lower was the TET, with these two factors being independent. This result indicated that fatigue was independently affected by both the increase in exercise intensity and the thermal environmental stress. Fatigue developed at different Tint and HSR showed the best inverse relationship with TET. We conclude that HSR was the main anticipating factor of fatigue.

  9. Twelfth annual US DOE low-level waste management conference

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    The papers in this document comprise the proceedings of the Department of Energy's Twelfth Annual Low-Level Radioactive Waste Management Conference, which was held in Chicago, Illinois, on August 28 and 29, 1990. General subjects addressed during the conference included: mixed waste, low-level radioactive waste tracking and transportation, public involvement, performance assessment, waste stabilization, financial assurance, waste minimization, licensing and environmental documentation, below-regulatory-concern waste, low-level radioactive waste temporary storage, current challenges, and challenges beyond 1990.

  10. Twelfth cranial nerve involvement in Guillian Barre syndrome

    Directory of Open Access Journals (Sweden)

    Subrat Kumar Nanda

    2013-01-01

    Full Text Available Guillian Barre Syndrome (GBS is associated with cranial nerve involvement. Commonest cranial nerves involved were the facial and bulbar (IXth and Xth. Involvement of twelfth cranial nerve is rare in GBS. We present a case of GBS in a thirteen years old boy who developed severe tongue weakness and wasting at two weeks after the onset of GBS. The wasting and weakness of tongue improved at three months of follow up. Brief review of the literature about XIIth cranial nerve involvement in GBS is discussed.

  11. Prediction of Heat Transfer Rates for Shell-and-Tube Heat Exchangers by Artificial Neural Networks Approach

    Institute of Scientific and Technical Information of China (English)

    Qiuwang WANG; Gongnan XIE; Ming ZENG; Laiqin LUO

    2006-01-01

    This work used artificial neural network (ANN) to predict the heat transfer rates of shell-and-tube heat exchangers with segmental baffles or continuous helical baffles, based on limited experimental data. The Back Propagation (BP) algorithm was used in training the networks. Different network configurations were also studied. The deviation between the predicted results and experimental data was less than 2%. Comparison with correlation for prediction shows ANN superiority. It is recommended that ANN can be easily used to predict the performances of thermal systems in engineering applications, especially to model heat exchangers for heat transfer analysis.

  12. Heating rate effect on thermoluminescence glow curves of LiF:Mg,Cu,P+PTFE phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, Mexico D.F. 04510 (Mexico); Gonzalez, P.R., E-mail: pedro.gonzalez@inin.gob.mx [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, C.P. 52750, Ocoyoacac, Estado de Mexico (Mexico); Azorin, J. [Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico); Furetta, C. [Touro University Rome, Division of Touro College New York, Circne Gianicolense 15-17, 00153 Rome (Italy)

    2011-10-15

    The influence of heating rate on the thermoluminescence (TL) property of LiF:Mg,Cu,P+PTFE was analyzed. The activation energy and the frequency factor as a function of the heating rate were determined. The kinetic parameters and their dependence on the heating rate were evaluated using the sequential quadratic programming glow curve deconvolution (SQPGCD). The results showed that as the heating rate increases, the peak intensity at the maximum (I{sub M}) decreases and shifts to higher temperature; similar behavior of the kinetics parameters was observed. - Highlights: >Heating rate influence on the thermoluminescence (TL) property of LiF:Mg,Cu,P was analyzed. > The kinetic parameters, activation energy and frequency factor were evaluated using the sequential quadratic programming glow curve deconvolution. > The peak intensity at the maximum (I{sub M}) of the glow curves decreases. > Shifts to higher temperature were observed as the heating rate increased. > Similar behavior of the kinetics parameters was noticed.

  13. An examination of heat rate improvements due to waste heat integration in an oxycombustion pulverized coal power plant

    Science.gov (United States)

    Charles, Joshua M.

    Oxyfuel, or oxycombustion, technology has been proposed as one carbon capture technology for coal-fired power plants. An oxycombustion plant would fire coal in an oxidizer consisting primarily of CO2, oxygen, and water vapor. Flue gas with high CO2 concentrations is produced and can be compressed for sequestration. Since this compression generates large amounts of heat, it was theorized that this heat could be utilized elsewhere in the plant. Process models of the oxycombustion boiler, steam cycle, and compressors were created in ASPEN Plus and Excel to test this hypothesis. Using these models, heat from compression stages was integrated to the flue gas recirculation heater, feedwater heaters, and to a fluidized bed coal dryer. All possible combinations of these heat sinks were examined, with improvements in coal flow rate, Qcoal, net power, and unit heat rate being noted. These improvements would help offset the large efficiency impacts inherent to oxycombustion technology.

  14. 78 FR 8684 - Twelfth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S

    Science.gov (United States)

    2013-02-06

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S AGENCY... RTCA Special Committee 222, Inmarsat AMS(R)S. SUMMARY: The FAA is issuing this notice to advise the public of the twelfth meeting of the RTCA Special Committee 222, Inmarsat AMS(R)S. DATES: The...

  15. Twelfth nerve paresis induced by an unusual posterior fossa arachnoid cyst: case report and literature review.

    Science.gov (United States)

    Tarantino, Roberto; Marruzzo, Daniele; Colistra, Davide; Mancarella, Cristina; Delfini, Roberto

    2014-08-01

    There are only three cases of arachnoid cysts inducing twelfth nerve paresis described in English medical literature. We herein report one more instance. Six weeks after surgery, the patient has almost fully recovered. This case underlines the importance of considering the arachnoid cyst as a possible cause of twelfth nerve paresis.

  16. Causal Factors Influencing Adversity Quotient of Twelfth Grade and Third-Year Vocational Students

    Science.gov (United States)

    Pangma, Rachapoom; Tayraukham, Sombat; Nuangchalerm, Prasart

    2009-01-01

    Problem statement: The aim of this research was to study the causal factors influencing students' adversity between twelfth grade and third-year vocational students in Sisaket province, Thailand. Six hundred and seventy two of twelfth grade and 376 third-year vocational students were selected by multi-stage random sampling techniques. Approach:…

  17. A Simple Rate Law Experiment Using a Custom-Built Isothermal Heat Conduction Calorimeter

    Science.gov (United States)

    Wadso, Lars; Li, Xi.

    2008-01-01

    Most processes (whether physical, chemical, or biological) produce or consume heat: measuring thermal power (the heat production rate) is therefore a typical method of studying processes. Here we describe the design of a simple isothermal heat conduction calorimeter built for use in teaching; we also provide an example of its use in simultaneously…

  18. EFFECT OF HEATING RATE ON THE THERMODYNAMIC PROPERTIES OF PULVERIZED COAL

    Energy Technology Data Exchange (ETDEWEB)

    Ramanathan Sampath

    2000-01-01

    This final technical report describes work performed under DOE Grant No. DE-FG22-96PC96224 during the period September 24, 1996 to September 23, 1999 which covers the entire performance period of the project. During this period, modification, alignment, and calibration of the measurement system, measurement of devolatilization time-scales for single coal particles subjected to a range of heating rates and temperature data at these time-scales, and analysis of the temperature data to understand the effect of heating rates on coal thermal properties were carried out. A new thermodynamic model was developed to predict the heat transfer behavior for single coal particles using one approach based on the analogy for thermal property of polymers. Results of this model suggest that bituminous coal particles behave like polymers during rapid heating on the order of 10{sup 4}-10{sup 5} K/s. At these heating rates during the early stages of heating, the vibrational part of the heat capacity of the coal molecules appears to be still frozen but during the transition from heat-up to devolatilization, the heat capacity appears to attain a sudden jump in its value as in the case of polymers. There are a few data available in the coal literature for low heating rate experiments (10{sup 2}-10{sup 3} K/s) conducted by UTRC, our industrial partner, in this project. These data were obtained for a longer heating duration on the order of several seconds as opposed to the 10 milliseconds heating time of the single particle experiments discussed above. The polymer analogy model was modified to include longer heating time on the order of several seconds to test these data. However, the model failed to predict these low heating rate data. It should be noted that UTRC's work showed reasonably good agreement with Merrick model heat capacity predictions at these low heating rates, but at higher heating rates UTRC observed that coal thermal response was heat flux dependent. It is concluded

  19. Direct measurement of heat transfer rates and coefficients in freezing processes by the use of heat flux sensors

    Energy Technology Data Exchange (ETDEWEB)

    Amarante, A.; Lanoiselle, J.L.; Ramirez, A.

    2003-10-01

    Heat exchange is often complex to assess in freezing equipment. Either the extensive calculation procedures based on product time-temperature data, or the lack of accurate thermophysical properties, or even the non-uniform processing conditions in industrial equipment, results in increased difficulty in calculating accurate heat exchange parameters. The present study aims to solve this kind of problem by introducing the use of heat flux sensors (or fluxmeters) for an online measurement of heat exchange parameters during freezing processes. Since food products often have irregular, moist and greasy surfaces, bad attachment of the sensors can lead to low accuracy in heat flux measurement. First, a technique was improved in this particular and a numerical procedure based on matching the experimental and simulated temperature histories was used to calibrate the sensors attached to Tylose gels submitted to freezing and thawing cycles. Following this, the sensors were applied directly to a vegetable product undergoing freezing in a static freezer to measure the instantaneous product heat release rate and the local heat transfer coefficient. A fluxmeter-plastic transducer was also developed and used, coupled to an anemometer to map axially and transversally the local effective heat transfer coefficient and air speed profiles in a Super-Contact freezing tunnel. Results were compared with numerical simulations and showed good agreement. Irregular air speed distribution and low efficiency heat transfer zones were accurately detected, providing information for equipment optimization. (author)

  20. Dielectric properties and heating rate of broccoli powder as related to radio-frequency heating

    Science.gov (United States)

    Recently, Salmonella contamination was identified in low-moisture foods including dried vegetable powder. Radio Frequency (RF) dielectric heating is a potential alternative pasteurization method with short heating time. Dielectric properties of broccoli powder with 6.9, 9.1, 12.2, and 14.9%, w. b....

  1. THE POSSIBILITIES OF CO2 EMISSION REDUCTION IN THE PROCESS OF STEEL CHARGE HEATING THROUGH THE SELECTION OF HEATING RATE

    Directory of Open Access Journals (Sweden)

    Barbara Halusiak

    2015-08-01

    Full Text Available The reduction of carbon dioxide emission is an important aspect of the economic policy of each country. Institutions promoting environmental protection seek to reduce the level of greenhouse gas emissions. One of the main emitters of harmful gases to the atmosphere is the steelmaking sector. The heating technology used in metallurgical works contributes to the amount of emitted carbon dioxide that forms as a result of the loss of steel and the combustion of fuel, whose thermal energy is used during the course of the charge heating process in the heating furnace. Achieving the imposed ecological targets by not exceeding the specified emission level is possible by implementing appropriate pollutant emission reducing technologies in the metallurgical industry. Based on numerical computation results, the effect of heating rate on the emission of carbon dioxide has been determined in the paper. This study demonstrates that by selecting the appropriate steel charge heating technology the emissions of greenhouse gases can be substantially reduced.

  2. Convective Heat Transfer Scaling of Ignition Delay and Burning Rate with Heat Flux and Stretch Rate in the Equivalent Low Stretch Apparatus

    Science.gov (United States)

    Olson, Sandra

    2011-01-01

    To better evaluate the buoyant contributions to the convective cooling (or heating) inherent in normal-gravity material flammability test methods, we derive a convective heat transfer correlation that can be used to account for the forced convective stretch effects on the net radiant heat flux for both ignition delay time and burning rate. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone heater to minimize buoyant effects while at the same time providing a forced stagnation flow on the sample, which ignites and burns as a ceiling fire. Ignition delay and burning rate data is correlated with incident heat flux and convective heat transfer and compared to results from other test methods and fuel geometries using similarity to determine the equivalent stretch rates and thus convective cooling (or heating) rates for those geometries. With this correlation methodology, buoyant effects inherent in normal gravity material flammability test methods can be estimated, to better apply the test results to low stretch environments relevant to spacecraft material selection.

  3. Analysis of Effect of Heat Pipe Parameters in Minimising the Entropy Generation Rate

    Directory of Open Access Journals (Sweden)

    Rakesh Hari

    2016-01-01

    Full Text Available Heat transfer and fluid flow in the heat pipe system result in thermodynamic irreversibility generating entropy. The minimum entropy generation principle can be used for optimum design of flat heat pipe. The objective of the present work is to minimise the total entropy generation rate as the objective function with different parameters of the flat heat pipe subjected to some constraints. These constraints constitute the limitations on the heat transport capacity of the heat pipe. This physical nonlinear programming problem with nonlinear constraints is solved using LINGO 15.0 software, which enables finding optimum values for the independent design variables for which entropy generation is minimum. The effect of heat load, length, and sink temperature on design variables and corresponding entropy generation is studied. The second law analysis using minimum entropy generation principle is found to be effective in designing performance enhanced heat pipe.

  4. Retrofits for improved heat rate and availability: Low-level heat recovery economizer retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Rubow, L.N.; Borden, M.; Boulay, R.B.; Buchanan, T.L.; Granger, J.F.; Horazak, D.A.; Phillips, N.A. (Gilbert/Commonwealth, Inc., Reading, PA (United States))

    1992-06-01

    The subject of this report, involves the recovery of heat from the flue gas to preheat combustion air and protect the air heater. Flue gas is a large potential source of heat, but this mode of heat recovery has seen limited application due to the corrosive environment created in plant tail-end systems by condensation in sulfur-laden flue gases. Several installations of low-level economizers'' (LLEs) have experienced varied degrees of success using cast iron-type heat exchangers. Alternate materials that may be suitable for this application were investigated in this project. The cost of various types of installations with regard to equipment arrangement, remaining plant life, plant capacity factor, plant operating modes, ambient temperature characteristics, fuel costs, utility cost evaluation methods, and external economic factors were investigated.

  5. Mixing rates and vertical heat fluxes north of Svalbard from Arctic winter to spring

    Science.gov (United States)

    Meyer, Amelie; Fer, Ilker; Sundfjord, Arild; Peterson, Algot K.

    2017-06-01

    Mixing and heat flux rates collected in the Eurasian Basin north of Svalbard during the N-ICE2015 drift expedition are presented. The observations cover the deep Nansen Basin, the Svalbard continental slope, and the shallow Yermak Plateau from winter to summer. Mean quiescent winter heat flux values in the Nansen Basin are 2 W m-2 at the ice-ocean interface, 3 W m-2 in the pycnocline, and 1 W m-2 below the pycnocline. Large heat fluxes exceeding 300 W m-2 are observed in the late spring close to the surface over the Yermak Plateau. The data consisting of 588 microstructure profiles and 50 days of high-resolution under-ice turbulence measurements are used to quantify the impact of several forcing factors on turbulent dissipation and heat flux rates. Wind forcing increases turbulent dissipation seven times in the upper 50 m, and doubles heat fluxes at the ice-ocean interface. The presence of warm Atlantic Water close to the surface increases the temperature gradient in the water column, leading to enhanced heat flux rates within the pycnocline. Steep topography consistently enhances dissipation rates by a factor of four and episodically increases heat flux at depth. It is, however, the combination of storms and shallow Atlantic Water that leads to the highest heat flux rates observed: ice-ocean interface heat fluxes average 100 W m-2 during peak events and are associated with rapid basal sea ice melt, reaching 25 cm/d.

  6. Insensitivity of Ion Motional Heating Rate to Trap Material over a Large Temperature Range

    CERN Document Server

    Chiaverini, J

    2014-01-01

    We present measurements of trapped-ion motional-state heating rates in niobium and gold surface-electrode ion traps over a range of trap-electrode temperatures from approximately 4 K up to room temperature (295 K) in a single apparatus. Using the sideband-ratio technique after resolved-sideband cooling of single ions to the motional ground state, we find low-temperature heating rates more than two orders of magnitude below the room-temperature values and approximately equal to the lowest measured heating rates in similarly-sized cryogenic traps. We find similar behavior in the two very different electrode materials, suggesting that the anomalous heating process is dominated by non-material-specific surface contaminants. Through precise control of the temperature of cryopumping surfaces, we also identify conditions under which elastic collisions with the background gas can lead to an apparent steady heating rate, despite rare collisions.

  7. Prediction of the Scale Removal Rate in Heat Exchanger Piping

    Directory of Open Access Journals (Sweden)

    Najwa S. Majeed

    2010-01-01

    Full Text Available The possibility of predicting the mass transfer controlled CaCO3 scale removal rate has been investigated.Experiments were carried out using chelating agents as a cleaning solution at different time and Reynolds’s number. The results of CaCO3 scale removal or (mass transfer rate (as it is the controlling process are compared with proposed model of prandtl’s and Taylor particularly based on the concept of analogy among momentum and mass transfer.Correlation for the variation of Sherwood number ( or mass transfer rate with Reynolds’s number have been obtained .

  8. Prediction of the heat transfer rate of a single layer wire-on-tube type heat exchanger using ANFIS

    Energy Technology Data Exchange (ETDEWEB)

    Hayati, Mohsen [Electrical Engineering Department, Faculty of Engineering, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran); Computational Intelligence Research Center, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran); Rezaei, Abbas; Seifi, Majid [Electrical Engineering Department, Faculty of Engineering, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran)

    2009-12-15

    In this paper, we applied an Adaptive Neuro-Fuzzy Inference System (ANFIS) model for prediction of the heat transfer rate of the wire-on-tube type heat exchanger. Limited experimental data was used for training and testing ANFIS configuration with the help of hybrid learning algorithm consisting of backpropagation and least-squares estimation. The predicted values are found to be in good agreement with the actual values from the experiments with mean relative error less than 2.55%. Also, we compared the proposed ANFIS model to an ANN approach. Results show that the ANFIS model has more accuracy in comparison to ANN approach. Therefore, we can use ANFIS model to predict the performances of thermal systems in engineering applications, such as modeling heat exchangers for heat transfer analysis. (author)

  9. Computer simulation of metal wire explosion under high rate heating

    Science.gov (United States)

    Zolnikov, K. P.; Kryzhevich, D. S.; Korchuganov, A. V.

    2017-05-01

    Synchronous electric explosion of metal wires and synthesis of bicomponent nanoparticles were investigated on the base of molecular dynamics method. Copper and nickel nanosized crystallites of cylindrical shape were chosen as conductors for explosion. The embedded atom approximation was used for calculation of the interatomic interactions. The agglomeration process after explosion metal wires was the main mechanism for particle synthesis. The distribution of chemical elements was non-uniform over the cross section of the bicomponent particles. The copper concentration in the surface region was higher than in the bulk of the synthesized particle. By varying the loading parameters (heating temperature, the distance between the wires) one can control the size and internal structure of the synthesized bicomponent nanoparticles. The obtained results showed that the method of molecular dynamics can be effectively used to determine the optimal technological mode of nanoparticle synthesis on the base of electric explosion of metal wires.

  10. The effect of heating rate on the surface chemistry of NiTi.

    Science.gov (United States)

    Undisz, Andreas; Hanke, Robert; Freiberg, Katharina E; Hoffmann, Volker; Rettenmayr, Markus

    2014-11-01

    The impact of the heating rate on the Ni content at the surface of the oxide layer of biomedical NiTi is explored. Heat treatment emulating common shape-setting procedures was performed by means of conventional and inductive heating for similar annealing time and temperature, applying various heating rates from ~0.25 K s(-1) to 250 K s(-1). A glow discharge optical emission spectroscopy method was established and employed to evaluate concentration profiles of Ni, Ti and O in the near-surface region at high resolution. The Ni content at the surface of the differently treated samples varies significantly, with maximum surface Ni concentrations of ~20 at.% at the lowest and ~1.5 at.% at the highest heating rate, i.e. the total amount of Ni contained in the surface region of the oxide layer decreases by >15 times. Consequently, the heating rate is a determinant for the biomedical characteristics of NiTi, especially since Ni available at the surface of the oxide layer may affect the hemocompatibility and be released promptly after surgical application of a respective implant. Furthermore, apparently contradictory results presented in the literature reporting surface Ni concentrations of ~3 at.% to >20 at.% after heat treatment are consistently explained considering the ascertained effect of the heating rate.

  11. Le mythe comme détour dans Twelfth Night The Myth as a Diversion in Twelfth Night

    Directory of Open Access Journals (Sweden)

    Cécile Mauré

    2009-06-01

    Full Text Available Being only rarely mentioned in the text, the myth might seem an anecdotal and trivial detail. The study of the myth of Echo and Narcissus in Twelfth Night shows us however that it is a decisive element in the reading and the understanding of the play. The references are numerous and often implicit. The characters themselves alternately play the roles of Echo and Narcissus. The play is structured as if it were a mirror in which the characters endlessly duplicate each other and echo their own words. Shakespeare plays with the different versions of the myth that he often blends with subtlety. For the sake of comedy, he dares to parody and demythologize Ovid’s story. The myth seems to divert our attention from the direction of the text but closer analysis suggests the reverse and invites us to find the meaning of the play which can be seen as a real labyrinth.

  12. Heat Conduction in a Functionally Graded Plate Subjected to Finite Cooling/Heating Rates: An Asymptotic Solution

    Directory of Open Access Journals (Sweden)

    Zhihe Jin

    2011-12-01

    Full Text Available This work investigates transient heat conduction in a functionally graded plate (FGM plate subjected to gradual cooling/heating at its boundaries. The thermal properties of the FGM are assumed to be continuous and piecewise differentiable functions of the coordinate in the plate thickness direction. A linear ramp function describes the cooling/heating rates at the plate boundaries. A multi-layered material model and Laplace transform are employed to obtain the transformed temperatures at the interfaces between the layers. An asymptotic analysis and an integration technique are then used to obtain a closed form asymptotic solution of the temperature field in the FGM plate for short times. The thermal stress intensity factor (TSIF for an edge crack in the FGM plate calculated based on the asymptotic temperature solution shows that the asymptotic solution can capture the peak TSIFs under the finite cooling rate conditions.

  13. Effect of the Heat Flux Density on the Evaporation Rate of a Distilled Water Drop

    Directory of Open Access Journals (Sweden)

    Ponomarev Konstantin

    2016-01-01

    Full Text Available This paper presents the experimental dependence of the evaporation rate of a nondeaerated distilled water drop from the heat flux density on the surfaces of non-ferrous metals (copper and brass. A drop was placed on a heated substrate by electronic dosing device. To obtain drop profile we use a shadow optical system; drop symmetry was controlled by a high-speed video camera. It was found that the evaporation rate of a drop on a copper substrate is greater than on a brass. The evaporation rate increases intensively with raising volume of a drop. Calculated values of the heat flux density and the corresponding evaporation rates are presented in this work. The evaporation rate is found to increase intensively on the brass substrate with raising the heat flux density.

  14. Effects of mass flow rate and droplet velocity on surface heat flux during cryogen spray cooling

    Energy Technology Data Exchange (ETDEWEB)

    Karapetian, Emil [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Aguilar, Guillermo [Department of Biomedical Engineering, University of California, Irvine, CA (United States); Kimel, Sol [Beckman Laser Institute, University of California, Irvine, CA (United States); Lavernia, Enrique J [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Nelson, J Stuart [Department of Biomedical Engineering, University of California, Irvine, CA (United States)

    2003-01-07

    Cryogen spray cooling (CSC) is used to protect the epidermis during dermatologic laser surgery. To date, the relative influence of the fundamental spray parameters on surface cooling remains incompletely understood. This study explores the effects of mass flow rate and average droplet velocity on the surface heat flux during CSC. It is shown that the effect of mass flow rate on the surface heat flux is much more important compared to that of droplet velocity. However, for fully atomized sprays with small flow rates, droplet velocity can make a substantial difference in the surface heat flux. (note)

  15. Can reptile embryos influence their own rates of heating and cooling?

    Science.gov (United States)

    Du, Wei-Guo; Tu, Ming-Chung; Radder, Rajkumar S; Shine, Richard

    2013-01-01

    Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars) cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. In a nest with diel thermal fluctuations, that hysteresis could increase the embryo's effective incubation temperature. The mechanisms for controlling rates of thermal exchange are unclear, but may involve facultative adjustment of blood flow. Heart rates of snake embryos were higher during cooling than during heating, the opposite pattern to that seen in adult reptiles. Our data challenge the view of reptile eggs as thermally passive, and suggest that embryos of reptile species with large eggs can influence their own rates of heating and cooling.

  16. Can reptile embryos influence their own rates of heating and cooling?

    Directory of Open Access Journals (Sweden)

    Wei-Guo Du

    Full Text Available Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. In a nest with diel thermal fluctuations, that hysteresis could increase the embryo's effective incubation temperature. The mechanisms for controlling rates of thermal exchange are unclear, but may involve facultative adjustment of blood flow. Heart rates of snake embryos were higher during cooling than during heating, the opposite pattern to that seen in adult reptiles. Our data challenge the view of reptile eggs as thermally passive, and suggest that embryos of reptile species with large eggs can influence their own rates of heating and cooling.

  17. Tailoring the characteristics of carbonized wood charcoal by using different heating rates

    Science.gov (United States)

    Kwon, Gu-Joong; Kim, Dae-Young; Oh, Choong-Hyeon; Park, Byung-Ho; Kang, Joo-Hyon

    2014-05-01

    This study examined the characteristics of charcoals generated from White Lauan ( Pentacmecontorta) and Punah ( Tetrameristaglabra) by using different carbonization temperatures and heating rates. The scanning electron micrographs showed vestured pits in the White Lauan and raphide crystals in Punah as their respective anatomical characteristics. A slower heating rate resulted in a lower temperature to obtain the same amount of weight loss, regardless of the species being tested. A greater charcoal yield was obtained at a higher heating rate. The specific surface area was smaller in the charcoal produced at a higher carbonization temperature, but the heating rate had little effected. For both wood species, the axial compressive strength of the charcoal increased as the carbonization temperature was increased. The X-ray diffractograms of White Lauan and Punah woods heated at 1200°C indicated thermal decomposition of the crystal structure of cellulose, but no appreciable structural changes occurred under the tested heating rate conditions. Overall, the heating rate affected the charcoal yield but not the specific surface area, compressive strength, and crystal structure.

  18. R&D on Resistive Heat Exchangers for HTS High Rated Current Leads%R&D on Resistive Heat Exchangers for HTS High Rated Current Leads

    Institute of Scientific and Technical Information of China (English)

    毕延芳

    2011-01-01

    The HTS current leads of superconducting magnets for large scale fusion devices and high energy particle colliders can reduce the power consumption for cooling by 2/3 compared with conventional leads. The resistive sections of high-rated current leads are usually made of a heat exchanger cooled by gas flow. The supply of the cooling mass flow incurs more than 90% of the cooling cost for the HTS leads. The mass flow rate requirement depends not only on the length and material of the resistive heat exchanger, but also on the heat transfer coefficient and HEX surface, the joint resistance at the cold end of a sheet-stack HEX with a larger specific presented in the paper. The test results of efficiency can be achieved. and its cooling approach. The design and operation surface and a much smaller hydraulic diameter are an HTS lead optimized for 8 kA show that a 98.4%

  19. Thermogravimetric characteristics of char obtained at high heat rate

    Directory of Open Access Journals (Sweden)

    Andrés Felipe Rojas González

    2010-05-01

    700°C, 800°C and 900°C to obtain their combustion profiles. Characteristic temperatures (ignition, peak and final tempe- ratures were determined by non-isothermal thermogravimetry; it was found that chars from La Yolanda coal gave the highest figures for the characteristic temperatures. Isothermal thermogravimetry revealed that the combustion rate for the three coals decreased with increased devolatilisation time and combustion temperature.

  20. Heat-Rate Improvement Obtained by Retubing Power-Plant Condenser Enhanced Tubes

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-21

    A utility will only retube a condenser with enhanced tubes if the incremental cost of the enhanced tubes can be offset with reduced fuel costs. The reduced fuel cost is obtained for some units because of the higher heat-transfer coefficient of enhanced tubes. They lead to improved condenser performance measured by a lower condenser pressure and therefore a more efficient power plant. However, the higher haet-transfer coefficients do not always guarantee that enhanced tubes will be more cost effective. Other issues must be considered such as the cooling-water flow reduction due to the increased pressure drop, the low-pressure turbine heat-rate variation with backpressure, and the cooling-water pump and system characteristics. These and other parameters must be considered to calculate the efficiency improvement of the power plant as commonly measured by the quantity known as the heat rate. Knowing the heat-rate improvement, the fuel cost, and the incremental increase of the enhanced tubes from the supplier, the payback time can be determined. This program calculates the heat-rate improvement that can be obtained by retubing a power plant condenser with enhanced tubes of a particular type called Korodense LPD made by Wolverine Tube, Inc. The fuel savings are easily established knowing the heat-rate improvement. All electrical utilities are potential users because a condenser is used as the heat sink for every power plant.

  1. HTRATE; Heat-Rate Improvement Obtained by Retubing Power-Plant Condenser Enhanced Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Rabas, T.J. [Argonne National Lab., IL (United States)

    1990-06-01

    A utility will only retube a condenser with enhanced tubes if the incremental cost of the enhanced tubes can be offset with reduced fuel costs. The reduced fuel cost is obtained for some units because of the higher heat-transfer coefficient of enhanced tubes. They lead to improved condenser performance measured by a lower condenser pressure and therefore a more efficient power plant. However, the higher haet-transfer coefficients do not always guarantee that enhanced tubes will be more cost effective. Other issues must be considered such as the cooling-water flow reduction due to the increased pressure drop, the low-pressure turbine heat-rate variation with backpressure, and the cooling-water pump and system characteristics. These and other parameters must be considered to calculate the efficiency improvement of the power plant as commonly measured by the quantity known as the heat rate. Knowing the heat-rate improvement, the fuel cost, and the incremental increase of the enhanced tubes from the supplier, the payback time can be determined. This program calculates the heat-rate improvement that can be obtained by retubing a power plant condenser with enhanced tubes of a particular type called Korodense LPD made by Wolverine Tube, Inc. The fuel savings are easily established knowing the heat-rate improvement. All electrical utilities are potential users because a condenser is used as the heat sink for every power plant.

  2. Average Rate of Heat-Related Hospitalizations in 23 States, 2001-2010

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the 2001–2010 average rate of hospitalizations classified as “heat-related” by medical professionals in 23 states that participate in CDC’s...

  3. Heat transfer in a microvascular network: the effect of heart rate on heating and cooling in reptiles (Pogona barbata and Varanus varius).

    Science.gov (United States)

    Seebacher, F

    2000-03-21

    Thermally-induced changes in heart rate and blood flow in reptiles are believed to be of selective advantage by allowing animal to exert some control over rates of heating and cooling. This notion has become one of the principal paradigms in reptilian thermal physiology. However, the functional significance of changes in heart rate is unclear, because the effect of heart rate and blood flow on total animal heat transfer is not known. I used heat transfer theory to determine the importance of heat transfer by blood flow relative to conduction. I validated theoretical predictions by comparing them with field data from two species of lizard, bearded dragons (Pogona barbata) and lace monitors (Varanus varius). Heart rates measured in free-ranging lizards in the field were significantly higher during heating than during cooling, and heart rates decreased with body mass. Convective heat transfer by blood flow increased with heart rate. Rates of heat transfer by both blood flow and conduction decreased with mass, but the mass scaling exponents were different. Hence, rate of conductive heat transfer decreased more rapidly with increasing mass than did heat transfer by blood flow, so that the relative importance of blood flow in total animal heat transfer increased with mass. The functional significance of changes in heart rate and, hence, rates of heat transfer, in response to heating and cooling in lizards was quantified. For example, by increasing heart rate when entering a heating environment in the morning, and decreasing heart rate when the environment cools in the evening a Pogona can spend up to 44 min longer per day with body temperature within its preferred range. It was concluded that changes in heart rate in response to heating and cooling confer a selective advantage at least on reptiles of mass similar to that of the study animals (0. 21-5.6 kg). Copyright 2000 Academic Press.

  4. An analysis of representative heating load lines for residential HSPF ratings

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    This report describes an analysis to investigate representative heating loads for single-family detached homes using current EnergyPlus simulations (DOE 2014a). Hourly delivered load results are used to determine binned load lines using US Department of Energy (DOE) residential prototype building models (DOE 2014b) developed by Pacific Northwest National Laboratory (PNNL). The selected residential single-family prototype buildings are based on the 2006 International Energy Conservation Code (IECC 2006) in the DOE climate regions. The resulting load lines are compared with the American National Standards Institute (ANSI)/Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240 (AHRI 2008) minimum and maximum design heating requirement (DHR) load lines of the heating seasonal performance factor (HSPF) ratings procedure for each region. The results indicate that a heating load line closer to the maximum DHR load line, and with a lower zero load ambient temperature, is more representative of heating loads predicted for EnergyPlus prototype residential buildings than the minimum DHR load line presently used to determine HSPF ratings. An alternative heating load line equation was developed and compared to binned load lines obtained from the EnergyPlus simulation results. The effect on HSPF of the alternative heating load line was evaluated for single-speed and two-capacity heat pumps, and an average HSPF reduction of 16% was found. The alternative heating load line relationship is tied to the rated cooling capacity of the heat pump based on EnergyPlus autosizing, which is more representative of the house load characteristics than the rated heating capacity. The alternative heating load line equation was found to be independent of climate for the six DOE climate regions investigated, provided an adjustable zero load ambient temperature is used. For Region IV, the default DOE climate region used for HSPF ratings, the higher load line results in an ~28

  5. Investigating the performance of simplified neutral-ion collisional heating rate in a global IT model

    Science.gov (United States)

    Zhu, Jie; Ridley, Aaron J.

    2016-01-01

    The Joule heating rate has usually been used as an approximate form of the neutral-ion collisional heating rate in the thermospheric energy equation in global thermosphere-ionosphere models. This means that the energy coupling has ignored the energy gained by the ions from collisions with electrons. It was found that the globally averaged thermospheric temperature (Tn) was underestimated in simulations using the Joule heating rate, by about 11% when F10.7=110 solar flux unit (sfu, 1 sfu = 10-22 W m-2 Hz-1) in a quiet geomagnetic condition. The underestimation of Tn was higher at low latitudes than high latitudes, and higher at F region altitudes than at E region altitudes. It was found that adding additional neutral photoelectron heating in a global IT model compensated for the underestimation of Tn using the Joule heating approximation. Adding direct photoelectron heating to the neutrals compensated for the indirect path for the energy that flows from the electrons to the ions then to the neutrals naturally and therefore was an adequate compensation over the dayside. There was a slight dependence of the underestimation of Tn on F10.7, such that larger activity levels resulted in a need for more compensation in direct photoelectron heating to the neutrals to make up for the neglected indirect heating through ions and electrons.

  6. Effect of Heating Rates on the Formable Oxide Scale on a C-Steel Surface

    Institute of Scientific and Technical Information of China (English)

    A.A.El-Meligi

    2004-01-01

    Oxide scale formation on a C-steel surface has been investigated using linear heating rates ranging from 0.1℃/min to 10℃/min at high temperatures. The studies on the oxide scale formation at high temperature (650℃) at slower heating rate (0.1℃/min) shows that the kinetic regime is linear. X-ray diffraction measurements revealed that the scale constituents are significantly influenced by the heating rate. The adherence of the scale was improved by using slower heating rate (0.1℃/min-≤650℃),while above such degree the scale was susceptible to cracking and flaking out of the alloy surface. In fact, the development of oxide growth stresses can cause considerable scale cracking. As well, variation of the crystallite sizes under the aforementioned conditions might affect the scale stacking to the alloy surface. The secondary electron detector images of the oxide scale shows that the scale was imperfectly smooth and there were a number of voids and defects in the scale skin, especially at fast heating rate. This observation could be attributed to defects of the as-received alloy. In general, slower heating rate reduced the defects of the scale and improved its adherence.

  7. Heat accumulation during high repetition rate ultrafast laser interaction: Waveguide writing in borosilicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibin; Eaton, Shane M; Li, Jianzhao; Herman, Peter R [The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King' s College Road, Toronto, ON, M5S 3G4 (Canada)

    2007-04-15

    During high repetition rate (>200 kHz) ultrafast laser waveguide writing, visible heat modified zones surrounding the formed waveguide occur as a result of heat accumulation. The radii of the heat-modified zones increase with the laser net fluence, and were found to correlate with the formation of low-loss and cylindrically symmetric optical waveguides. A numerical thermal model based on the finite difference method is applied here to account for cumulative heating and diffusion effects. The model successfully shows that heat propagation and accumulation accurately predict the radius of the 'heat modified' zones observed in borosilicate glass waveguides formed across a wide range of laser exposure conditions. Such modelling promises better control of thermal effects for optimizing the fabrication and performance of three-dimensional optical devices in transparent materials.

  8. Dilatometric and hardness analysis of C45 steel tempering with different heating-up rates

    Directory of Open Access Journals (Sweden)

    A. Kulawik

    2012-01-01

    Full Text Available Modelling of technological processes of heat treatment or welding, involving multiple heat source transitions, requires considering the phenomenon of tempering. In work have been presented results of dilatometric research of hardened C45 steel subjected to tempering. The analysis of the influence of heating rate at the kinetic determined from dilatometric curves has been made. There have also been estimated quantities of transformation expansions and thermal expansion coefficients of hardening and tempering structures (austenite, ferrite, pearlite, martensite and sorbite. The analysis of tempering time influence on the hardness of tempered steel has been made. Functions associating hardness with tempering time (rate of heating-up in technological processes based on short-timed action of a heat source (eg. laser treatment have been suggested.

  9. Experimental test of the heating and cooling rate effect on blocking temperatures

    Science.gov (United States)

    Berndt, Thomas; Paterson, Greig A.; Cao, Changqian; Muxworthy, Adrian R.

    2017-07-01

    The cooling rates at which rocks acquire thermoremanent magnetizations (TRMs), affect their unblocking temperatures in thermal demagnetization experiments; similarly the heating rates at which the thermal demagnetization experiments are done also affect the unblocking temperature. We have tested the effects of variable cooling and heating rates on the unblocking temperatures of two natural non-interacting, magnetically uniform (single-domain, SD) (titano)magnetite samples and a synthetic SD magnetoferritin sample. While previous studies have only considered unblocking temperatures for stepwise thermal demagnetization data (i.e. the room-temperature magnetization after incremental heating), in this work we derive an expression for continuous thermal demagnetization of both TRMs and viscous remanent magnetizations (VRMs) and relate the heating rate to an effective equivalent hold time of a stepwise thermal demagnetization experiment. Through our analysis we reach four main conclusions: First, the theoretical expressions for the heating/cooling rate effect do not accurately predict experimentally observed blocking temperatures. Empirically, the relation can be modified incorporating a factor that amplifies both the temperature and the heating rate dependence of the heating/cooling rate effect. Using these correction factors, Pullaiah nomograms can accurately predict blocking temperatures of both TRMs and VRMs for continuous heating/cooling. Second, demagnetization temperatures are approximately predicted by published 'Pullaiah nomograms', but blocking occurs gradually over temperature intervals of 5-40 K. Third, the theoretically predicted temperatures correspond to ∼54-82 per cent blocking, depending on the sample. Fourth, the blocking temperatures can be used to obtain estimates of the atomic attempt time τ0, which were found to be 3 × 10-10 s for large grained (titano)magnetite, 1 × 10-13 s for small grained (titano)magnetite below the Verwey transition and 9

  10. Effect of heating rate on structure of VT23 and VT6 quenched alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M.; Oshkaderov, S.P. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1982-01-01

    The grain and intergrain structures of two-phase VT23 and VT6 titanium alloys with an initial fine-grain structure quenched after heating with different rates in (..cap alpha..+..beta..) and ..beta..-regions were studied. The heating rate increase from 0.2 up to 200 deg/s is shown to result in the monotonic growth of a polymorphic transformation temperature, the decrease of grain size at a constant quenching temperature, the appearance of a grain size change jump, and the martensite grain refinement during heating up to ..beta..-region temperatures. The high-rate heating of VT23 and VT6 quenched alloys permits to build up dispersion intergranular structure and to control their properties.

  11. Measurement of Ion Motional Heating Rates over a Range of Trap Frequencies and Temperatures

    CERN Document Server

    Bruzewicz, C D; Chiaverini, J

    2014-01-01

    We present measurements of the motional heating rate of a trapped ion at different trap frequencies and temperatures between $\\sim$0.6 and 1.5 MHz and $\\sim$4 and 295 K. Additionally, we examine the possible effect of adsorbed surface contaminants with boiling points below $\\sim$105$^{\\circ}$C by measuring the ion heating rate before and after locally baking our ion trap chip under ultrahigh vacuum conditions. We compare the heating rates presented here to those calculated from available electric-field noise models. We can tightly constrain a subset of these models based on their expected frequency and temperature scaling interdependence. Discrepancies between the measured results and predicted values point to the need for refinement of theoretical noise models in order to more fully understand the mechanisms behind motional trapped-ion heating.

  12. Effect of Heating Rate on the Pressureless Sintering Densification of a Nickel-Based Superalloy

    Science.gov (United States)

    Levasseur, David; Brochu, Mathieu

    2016-05-01

    Pressureless sintering of Inconel 718 has important technological applications for the densification of metal injection molding or additive manufacturing of parts with powder/binder systems. The effect of heating rates ranging from 15 to 200 K/minute on the sintering behavior of fine (-325 mesh) Inconel 718 powders was studied using the master sintering curve (MSC) concept. A pressureless pulsed electric current sintering setup was used to heat samples. The temperature at the onset of sintering increased as the heating rate increased. The formation of a supersolidus liquid fraction was shifted toward higher temperatures for increased heating rates. The apparent activation energy of sintering was obtained by least squares fitting of the sintering data to the MSC and was in good agreement with the lattice diffusion activation energy of the alloying elements present in Inconel 718. The MSC followed different kinetics for low heating rates (≤50 K/minute) and high heating rates (≥75 K/minute), and these differences were related to liquation kinetics.

  13. The heating rate in the tropical tropopause region; Die Erwaermungsrate in der tropischen Tropopausenregion

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, Ulrich

    2010-07-01

    The major part of the movement of air masses from the troposphere to the stratosphere takes place in the tropics. The conveyed air mass is transported with the Brewer-Dobson circulation poleward and therefore influences the global stratospheric composition. An important cause variable for the transport of air through the tropical tropopause layer (TTL) is the radiative heating, which is investigated in this work. The influence of trace gases, temperature, and cloudiness on the heating rate is quantified, especially the effect of the overlap of several cloud layers is discussed. The heating rate in the tropics is simulated for one year. Regional differences of the heating rate profile appear between convective and stably stratified regions. By means of trace gas concentrations, temperature, and heating rates it is determined that an enhanced transport of air through the TTL took place between January and April 2007. The comparison with previous works shows that accurate input data sets of trace gases, temperature, and cloudiness and exact methods for the simulation of the radiative transfer are indispensable for modeling of the heating rate with the required accuracy. (orig.)

  14. Influence of heat transfer rates on pressurization of liquid/slush hydrogen propellant tanks

    Science.gov (United States)

    Sasmal, G. P.; Hochstein, J. I.; Hardy, T. L.

    1993-01-01

    A multi-dimensional computational model of the pressurization process in liquid/slush hydrogen tank is developed and used to study the influence of heat flux rates at the ullage boundaries on the process. The new model computes these rates and performs an energy balance for the tank wall whereas previous multi-dimensional models required a priori specification of the boundary heat flux rates. Analyses of both liquid hydrogen and slush hydrogen pressurization were performed to expose differences between the two processes. Graphical displays are presented to establish the dependence of pressurization time, pressurant mass required, and other parameters of interest on ullage boundary heat flux rates and pressurant mass flow rate. Detailed velocity fields and temperature distributions are presented for selected cases to further illuminate the details of the pressurization process. It is demonstrated that ullage boundary heat flux rates do significantly effect the pressurization process and that minimizing heat loss from the ullage and maximizing pressurant flow rate minimizes the mass of pressurant gas required to pressurize the tank. It is further demonstrated that proper dimensionless scaling of pressure and time permit all the pressure histories examined during this study to be displayed as a single curve.

  15. Twelfth International Symposium on Recent Advances in Environmental Health Research.

    Science.gov (United States)

    Tchounwou, Paul B

    2016-05-04

    During the past century, environmental hazards have become a major concern, not only to public health professionals, but also to the society at large because of their tremendous health, socio-cultural and economic impacts. Various anthropogenic or natural factors have been implicated in the alteration of ecosystem integrity, as well as in the development of a wide variety of acute and/or chronic diseases in humans. It has also been demonstrated that many environmental agents, acting either independently or in combination with other toxins, may induce a wide range of adverse health outcomes. Understanding the role played by the environment in the etiology of human diseases is critical to designing cost-effective control/prevention measures. This special issue of International Journal of Environmental Research and Public Health includes the proceedings of the Twelfth International Symposium on Recent Advances in Environmental Health Research. The Symposium provided an excellent opportunity to discuss the scientific advances in biomedical, environmental, and public health research that addresses global environmental health issues.

  16. The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Mamum, Md Abdullah A. [Old Dominion Univ., Norfolk, VA (United States); Elmustafa, Abdelmageed A, [Old Dominion Univ., Norfolk, VA (United States); Stutzman, Marcy L. [JLAB, Newport News, VA (United States); Adderley, Philip A. [JLAB, Newport News, VA (United States); Poelker, Matthew [JLAB, Newport News, VA (United States)

    2014-03-01

    The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed a significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.

  17. Modeling the influence of potassium content and heating rate on biomass pyrolysis

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Surup, Gerrit; Shapiro, Alexander

    2017-01-01

    This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing. The shrink......This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing....... The shrinking particle model considers internal and external heat transfer limitations and incorporates catalytic effects of potassium on the product yields. Modeling parameters were tuned with experimentally determined char yields at high heating rates (>200 K s−1) using a wire mesh reactor, a single particle...... burner, and a drop tube reactor. The experimental data demonstrated that heating rate and potassium content have significant effects on the char yield. The importance of shrinkage on the devolatilization time becomes greater with increasing particle size, but showed little influence on the char yields....

  18. Thermomagnetic behavior of magnetic susceptibility – heating rate and sample size effects

    Directory of Open Access Journals (Sweden)

    Diana eJordanova

    2016-01-01

    Full Text Available Thermomagnetic analysis of magnetic susceptibility k(T was carried out for a number of natural powder materials from soils, baked clay and anthropogenic dust samples using fast (11oC/min and slow (6.5oC/min heating rates available in the furnace of Kappabridge KLY2 (Agico. Based on the additional data for mineralogy, grain size and magnetic properties of the studied samples, behaviour of k(T cycles and the observed differences in the curves for fast and slow heating rate are interpreted in terms of mineralogical transformations and Curie temperatures (Tc. The effect of different sample size is also explored, using large volume and small volume of powder material. It is found that soil samples show enhanced information on mineralogical transformations and appearance of new strongly magnetic phases when using fast heating rate and large sample size. This approach moves the transformation at higher temperature, but enhances the amplitude of the signal of newly created phase. Large sample size gives prevalence of the local micro- environment, created by evolving gases, released during transformations. The example from archeological brick reveals the effect of different sample sizes on the observed Curie temperatures on heating and cooling curves, when the magnetic carrier is substituted magnetite (Mn0.2Fe2.70O4. Large sample size leads to bigger differences in Tcs on heating and cooling, while small sample size results in similar Tcs for both heating rates.

  19. Distributed measurement of flow rate in conduits using heated fiber optic distributed temperature sensing

    Science.gov (United States)

    Sánchez, Raúl; Zubelzu, Sergio; Rodríguez-Sinobas, Leonor; Juana, Luis

    2016-04-01

    In some cases flow varies along conduits, such as in irrigated land drainage pipes and channels, irrigation laterals and others. Detailed knowledge of flow rate along the conduit makes possible analytical evaluation of water distribution and collection systems performance. Flow rate can change continuously in some systems, like in drainage pipes and channels, or abruptly, like in conduits bifurcations or emitter insertions. A heat pulse along the conduit makes possible to get flow rate from continuity and heat balance equations. Due to the great value of specific heat of water, temperature changes along conduit are smaller than the noise that involves the measurement process. This work presents a methodology that, dealing with the noise of distributed temperature measurements, leads to flow rate determination along pressurized pipes or open channel flows.

  20. Pyrolysis polygeneration of poplar wood: Effect of heating rate and pyrolysis temperature.

    Science.gov (United States)

    Chen, Dengyu; Li, Yanjun; Cen, Kehui; Luo, Min; Li, Hongyan; Lu, Bin

    2016-10-01

    The pyrolysis of poplar wood were comprehensively investigated at different pyrolysis temperatures (400, 450, 500, 550, and 600°C) and at different heating rates (10, 30, and 50°C/min). The results showed that BET surface area of biochar, the HHV of non-condensable gas and bio-oil reached the maximum values of 411.06m(2)/g, 14.56MJ/m(3), and 14.39MJ/kg, under the condition of 600°C and 30°C/min, 600°C and 50°C/min, and 550°C and 50°C/min, respectively. It was conducive to obtain high mass and energy yield of bio-oil at 500°C and higher heating rate, while lower pyrolysis temperature and heating rate contributed towards obtaining both higher mass yield and energy yield of biochar. However, higher pyrolysis temperature and heating rate contributed to obtain both higher mass yield and energy yield of the non-condensable gas. In general, compared to the heating rate, the pyrolysis temperature had more effect on the product properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Effect of heating rate on the thermoluminescence and thermal properties of natural ulexite.

    Science.gov (United States)

    Topaksu, M; Correcher, V; Garcia-Guinea, J; Yüksel, M

    2014-10-31

    Boron-rich compounds are of interest in the nuclear industry because they exhibit a high neutron absorption cross section. The manufacture of these materials involves the application of thermal and chemical treatments. This paper focuses on the study of the effect of the heating rate (HR) in two thermal techniques, differential thermal analysis (DTA) and thermoluminescence (TL), performed on natural ulexite from Bigadiç-Balıkesir (Turkey). The TL measurements were performed at six different heating rates in the range of 25-240°Cmin(-1). The UV-blue TL emission of natural ulexite shifted toward higher temperatures with increasing heating rate, whereas the intensity decreased. The kinetic parameters of the ulexite (Ea=0.65(9) eV and s=1.22×10(12)s(-1)) were calculated using the variable heating rate method. DTA measurements performed in the range of 0.5-10°Cmin(-1) displayed similar behavior to that of the TL response, despite the differences in technique and HR values. The DTA results indicated that natural ulexite exhibits two endothermic peaks originating from different processes: (i) a phase transition between the pentahydrated ulexite phase and a triple-hydrated phase and (ii) dehydration, dehydroxylation and alkali and earth-alkali self-diffusion processes in the ulexite lattice. The main endothermic peak shifted from 160°C to 250°C as the heating rate was increased.

  2. Determination of Kinetic Parameters for Thermal Decomposition of Phenolic Ablative Materials by Multiple Heating Rate Method

    Science.gov (United States)

    1980-07-01

    the ratio method to analyze thermogravimetric data obtained for a urethane polymer. Baer, Hedges, Seader , Jayakar, and Wojcik6 heated samples of...reinforced polymers at heating rates up to 4200°C/min. The data were correlated by a numerical technique developed by Burningham and Seader .7 Friedman...Decomposition Through Thermogravimetric Analysis," Thermochimica Acta, No, 1, (1970), pp. 147-158. 6. A. D. Baer, J. H. Hedges, J. D. Seader , K. M. Jayakar

  3. Tuning of Heat Transfer Rate of Cobalt Manganese Ferrite Based Magnetic Fluids in Varying Magnetic Field

    Directory of Open Access Journals (Sweden)

    Margabandhu MARIMUTHU

    2017-08-01

    Full Text Available Magnetic fluids are the colloidal solutions containing suspended magnetic nanoparticles in carrier fluids. The present work analyzed the heat transfer characteristics of de-ionized water and transformer oil (base fluids based cobalt manganese ferrite (Co1-xMnxFe2O4 coated with oleic acid synthesized via co-precipitation technique magnetic fluids in  varying magnetic field. Experimental investigations were carried out to analyze the heat transfer property of synthesized magnetic fluids (MNF in varying magnetic field applied in perpendicular direction to the thermal gradient of magnetic fluids. The experimental results indicate that the magnetic fluids show enhancement in heat transfer rate than carrier fluids in absence of magnetic field and it shows decrement in heat transfer rate in presence of varying magnetic field. Thus, the results reveal that the heat transfer characteristics of cobalt manganese ferrite based magnetic fluids was tunable by controlling the direction and influence of magnetic field strength. This tunable heat transfer property of cobalt manganese ferrite based magnetic fluids could be applicable in heat transport phenomena of transformers and in microelectronic devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16662

  4. Standard Test Method for Measuring Heat Transfer Rate Using a Thin-Skin Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the design and use of a thin metallic calorimeter for measuring heat transfer rate (also called heat flux). Thermocouples are attached to the unexposed surface of the calorimeter. A one-dimensional heat flow analysis is used for calculating the heat transfer rate from the temperature measurements. Applications include aerodynamic heating, laser and radiation power measurements, and fire safety testing. 1.2 Advantages 1.2.1 Simplicity of ConstructionThe calorimeter may be constructed from a number of materials. The size and shape can often be made to match the actual application. Thermocouples may be attached to the metal by spot, electron beam, or laser welding. 1.2.2 Heat transfer rate distributions may be obtained if metals with low thermal conductivity, such as some stainless steels, are used. 1.2.3 The calorimeters can be fabricated with smooth surfaces, without insulators or plugs and the attendant temperature discontinuities, to provide more realistic flow conditions for ...

  5. Heat rate curve approximation for power plants without data measuring devices

    Energy Technology Data Exchange (ETDEWEB)

    Poullikkas, Andreas [Electricity Authority of Cyprus, P.O. Box 24506, 1399 Nicosia (CY

    2012-07-01

    In this work, a numerical method, based on the one-dimensional finite difference technique, is proposed for the approximation of the heat rate curve, which can be applied for power plants in which no data acquisition is available. Unlike other methods in which three or more data points are required for the approximation of the heat rate curve, the proposed method can be applied when the heat rate curve data is available only at the maximum and minimum operating capacities of the power plant. The method is applied on a given power system, in which we calculate the electricity cost using the CAPSE (computer aided power economics) algorithm. Comparisons are made when the least squares method is used. The results indicate that the proposed method give accurate results.

  6. Heat rate curve approximation for power plants without data measuring devices

    Directory of Open Access Journals (Sweden)

    Andreas Poullikkas

    2012-01-01

    Full Text Available In this work, a numerical method, based on the one-dimensional finite difference technique, is proposed for the approximation of the heat rate curve, which can be applied for power plants in which no data acquisition is available. Unlike other methods in which three or more data points are required for the approximation of the heat rate curve, the proposed method can be applied when the heat rate curve data is available only at the maximum and minimum operating capacities of the power plant. The method is applied on a given power system, in which we calculate the electricity cost using the CAPSE (computer aided power economics algorithm. Comparisons are made when the least squares method is used. The results indicate that the proposed method give accurate results.

  7. Molecular dynamics simulations of aggregation of copper nanoparticles with different heating rates

    Science.gov (United States)

    Li, Qibin; Wang, Meng; Liang, Yunpei; Lin, Liyang; Fu, Tao; Wei, Peitang; Peng, Tiefeng

    2017-06-01

    Molecular dynamics simulations were employed to investigate the heating rates' effect on aggregation of two copper nanoparticles. The aggregation can be distinguished into three distinct regimes by the contacting and melting of nanoparticles. The nanoparticles contacting at a lower temperature during the sintering with lower heating rate, meanwhile, some temporary stacking fault exists at the contacting neck. The aggregation properties of the system, i.e. neck diameter, shrinkage ratio, potential energy, mean square displacement (MSD) and relative gyration radius, experience drastic changes due to the free surface annihilation. After the nanoparticles coalesced for a stable period, the shrinkage ratio, MSD, relative gyration radius and neck diameter of the system are dramatically changed during the melting process. It is shown that the shrinkage ratio and MSD have relative larger increasing ratio for a lower heating rate. While the evolution of the relative gyration radius and neck diameter is only sensitive to the temperature.

  8. Shortwave radiative heating rate profiles in hazy and clear atmosphere: a sensitivity study

    Science.gov (United States)

    Doppler, Lionel; Fischer, Jürgen; Ravetta, François; Pelon, Jacques; Preusker, René

    2010-05-01

    Aerosols have an impact on shortwave heating rate profiles (additional heating or cooling). In this survey, we quantify the impact of several key-parameters on the heating rate profiles of the atmosphere with and without aerosols. These key-parameters are: (1) the atmospheric model (tropical, midlatitude summer or winter, US Standard), (2) the integrated water vapor amount (IWV ), (3) the ground surface (flat and rough ocean, isotropic surface albedo for land), (4) the aerosol composition (dusts, soots or maritimes mixtures with respect to the OPAC-database classification), (5) the aerosol optical depth and (6) vertical postion, and (7) the single-scattering albedo (?o) of the aerosol mixture. This study enables us to evaluate which parameters are most important to take into account in a radiative energy budget of the atmosphere and will be useful for a future study: the retrieval of heating rates profiles from satellite data (CALIPSO, MODIS, MERIS) over the Mediterranean Sea. All the heating rates are computed by using the vector irradiances computed at each pressure level in the spectral interval 0.2 - 3.6μm (shortwave) by the 1D radiative transfer model for atmosphere and ocean: MOMO (Matrix-Operator MOdel) of the Institute for Space Science, FU Berlin 1

  9. Effects of heating rate on slow pyrolysis behavior, kinetic parameters and products properties of moso bamboo.

    Science.gov (United States)

    Chen, Dengyu; Zhou, Jianbin; Zhang, Qisheng

    2014-10-01

    Effects of heating rate on slow pyrolysis behaviors, kinetic parameters, and products properties of moso bamboo were investigated in this study. Pyrolysis experiments were performed up to 700 °C at heating rates of 5, 10, 20, and 30 °C/min using thermogravimetric analysis (TGA) and a lab-scale fixed bed pyrolysis reactor. The results show that the onset and offset temperatures of the main devolatilization stage of thermogravimetry/derivative thermogravimetry (TG/DTG) curves obviously shift toward the high-temperature range, and the activation energy values increase with increasing heating rate. The heating rate has different effects on the pyrolysis products properties, including biochar (element content, proximate analysis, specific surface area, heating value), bio-oil (water content, chemical composition), and non-condensable gas. The solid yields from the fixed bed pyrolysis reactor are noticeably different from those of TGA mainly because the thermal hysteresis of the sample in the fixed bed pyrolysis reactor is more thorough.

  10. Heat and water rate transfer processes in the human respiratory tract at various altitudes.

    Science.gov (United States)

    Kandjov, I M

    2001-02-01

    The process of the respiratory air conditioning as a process of heat and mass exchange at the interface inspired air-airways surface was studied. Using a model of airways (Olson et al., 1970) where the segments of the respiratory tract are like cylinders with a fixed length and diameter, the corresponding heat transfer equations, in the paper are founded basic rate exchange parameters-convective heat transfer coefficient h(c)(W m(-2) degrees C(-1)) and evaporative heat transfer coefficient h(e)(W m(-2)hPa(-1)). The rate transfer parameters assumed as sources with known heat power are connected to airflow rate in different airways segments. Relationships expressing warming rate of inspired air due to convection, warming rate of inspired air due to evaporation, water diffused in the inspired air from the airways wall, i.e. a system of air conditioning parameters, was composed. The altitude dynamics of the relations is studied. Every rate conditioning parameter is an increasing function of altitude. The process of diffusion in the peripheral bronchial generations as a basic transfer process is analysed. The following phenomenon is in effect: the diffusion coefficient increases with altitude and causes a compensation of simultaneous decreasing of O(2)and CO(2)densities in atmospheric air. Due to this compensation, the diffusion in the peripheral generations with altitude is approximately constant. The elements of the human anatomy optimality as well as the established dynamics are discussed and assumed. The square form of the airways after the trachea expressed in terms of transfer supposes (in view of maximum contact surface), that a maximum heat and water exchange is achieved, i.e. high degree of air condition at fixed environmental parameters and respiration regime.

  11. Rate of heat transfer in polypropylene tubes in solar water heaters

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, J.; Mahmoodi, M. [Sharif University of Technology, Tehran (Iran). Chemical Engineering Dept.; Riazi, M.R. [Kuwait Univ., Safat (Kuwait). Chemical Engineering Dept.

    2003-06-01

    A heat transfer rate was determined for polypropylene tubes in solar water heaters for the Reynolds number range 800-5600. Experiments were conducted in ambient temperatures of 34 to 37 {sup o}C. Data were correlated in the form of Nusselt numbers as: Nu=0.0015 Re{sup 0.75}Pr{sup 1/3} with correlation coefficient of 0.95. Such data can be used to predict heat transfer rates in a polypropylene solar heater in Tehran where the experiments were performed. An application of the results is shown in an example. (author)

  12. Products from the high temperature pyrolysis of RDF at slow and rapid heating rates

    OpenAIRE

    2015-01-01

    The high-temperature pyrolysis behaviour of a sample of refuse derived fuel (RDF) as a model of municipal solid waste (MSW) was investigated in a horizontal tubular reactor between 700 and 900 °C, at varying heating rates, and at an extended vapour residence time. Experiments were designed to evaluate the influence of process conditions on gas yields as well as gas and oil compositions. Pyrolysis of RDF at 800 °C and at rapid heating rate resulted in the gas yield with the highest CV of 24.8 ...

  13. Existing and Past Methods of Test and Rating Standards Related to Integrated Heat Pump Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Reedy, Wayne R. [Sentech, Inc.

    2010-07-01

    This report evaluates existing and past US methods of test and rating standards related to electrically operated air, water, and ground source air conditioners and heat pumps, 65,000 Btu/hr and under in capacity, that potentiality incorporate a potable water heating function. Two AHRI (formerly ARI) standards and three DOE waivers were identified as directly related. Six other AHRI standards related to the test and rating of base units were identified as of interest, as they would form the basis of any new comprehensive test procedure. Numerous other AHRI and ASHRAE component test standards were also identified as perhaps being of help in developing a comprehensive test procedure.

  14. Effects of whole body heating on dynamic baroreflex regulation of heart rate in humans

    Science.gov (United States)

    Crandall, C. G.; Zhang, R.; Levine, B. D.

    2000-01-01

    The purpose of this project was to identify whether dynamic baroreflex regulation of heart rate (HR) is altered during whole body heating. In 14 subjects, dynamic baroreflex regulation of HR was assessed using transfer function analysis. In normothermic and heat-stressed conditions, each subject breathed at a fixed rate (0. 25 Hz) while beat-by-beat HR and systolic blood pressure (SBP) were obtained. Whole body heating significantly increased sublingual temperature, HR, and forearm skin blood flow. Spectral analysis of HR and SBP revealed that the heat stress significantly reduced HR and SBP variability within the high-frequency range (0.2-0.3 Hz), reduced SBP variability within the low-frequency range (0.03-0.15 Hz), and increased the ratio of low- to high-frequency HR variability (all P regulation of HR within the high-frequency range (from 1.04 +/- 0.06 to 0.54 +/- 0.6 beats. min(-1). mmHg(-1); P body heating reduced high-frequency dynamic baroreflex regulation of HR associated with spontaneous changes in blood pressure. Reduced vagal baroreflex regulation of HR may contribute to reduced orthostatic tolerance known to occur in humans during heat stress.

  15. Measurement of the heating rate of strongly coupled ^9Be^+ ions in a Penning trap

    Science.gov (United States)

    Jensen, M. J.; Hasegawa, T.; Bollinger, J. J.; Dubin, D. H. E.

    2003-10-01

    We have measured the temperature and heating rate of laser-cooled ^9Be^+ ions stored in a 4.5 T Penning trap. Up to ˜10^6 ^9Be^+ ions were laser cooled to mK temperatures where they form a crystal with a ˜20 μm interparticle spacing. We measured the ion temperature by Doppler laser spectroscopy on a single-photon transition. Immediately after turning off the cooling laser (t=0) we measured T ˜1 mK, which is close to the Doppler cooling limit. A slow heating rate of less than 100 mK/s is observed for t<200 ms, where t is the length of time the cooling laser is off. This is followed by a sudden, rapid heating on the order of 2 K in 0.1 s. The onset of the rapid heating occurs at the Coulomb coupling parameter of the solid-liquid phase transition, Γ ˜170. We therefore believe the rapid heating is a manifestation of the phase transition and will discuss our investigations into possible causes of this heating.

  16. A real-time heat strain risk classifier using heart rate and skin temperature.

    Science.gov (United States)

    Buller, Mark J; Latzka, William A; Yokota, Miyo; Tharion, William J; Moran, Daniel S

    2008-12-01

    Heat injury is a real concern to workers engaged in physically demanding tasks in high heat strain environments. Several real-time physiological monitoring systems exist that can provide indices of heat strain, e.g. physiological strain index (PSI), and provide alerts to medical personnel. However, these systems depend on core temperature measurement using expensive, ingestible thermometer pills. Seeking a better solution, we suggest the use of a model which can identify the probability that individuals are 'at risk' from heat injury using non-invasive measures. The intent is for the system to identify individuals who need monitoring more closely or who should apply heat strain mitigation strategies. We generated a model that can identify 'at risk' (PSI 7.5) workers from measures of heart rate and chest skin temperature. The model was built using data from six previously published exercise studies in which some subjects wore chemical protective equipment. The model has an overall classification error rate of 10% with one false negative error (2.7%), and outperforms an earlier model and a least squares regression model with classification errors of 21% and 14%, respectively. Additionally, the model allows the classification criteria to be adjusted based on the task and acceptable level of risk. We conclude that the model could be a valuable part of a multi-faceted heat strain management system.

  17. Effect of the heating rate on the morphology of the pyrolytic char from hazelnut shell

    Energy Technology Data Exchange (ETDEWEB)

    Hanzade, H.A.; Serdar, Y. [Istanbul Technical Univ., Istanbul (Turkey). Faculty of Chemical and Metallurgical Engineering

    2008-07-01

    Although biomass chars have a high potential for use in various applications, their performance is directly related to the chemical and the physical properties of the chars. The surface area, porosity, pore size distribution, and density are the physical properties that determine the suitability of the chars to be used. Hazelnut shells are touted as being an extremely appropriate feedstock for high quality pyrolytic char, but the working conditions under which char is obtained have significant influence on the char structure and its properties, such as the thermal reactivity. Therefore, effects of the various parameters on the char structure must be considered. In this context, the present study focused on the physical changes that occur in char as a result of different heating rates during the pyrolysis of hazelnut shells. The effects of the heating rate on the structure of the pyrolytic char obtained from ground hazelnut shells under six different heating rate conditions were investigated. The hazelnut shell was burned in a thermogravimetric analyzer (TGA) under nitrogen flow. Non-isothermal heating was performed from ambient to 900 degrees C and held at this temperature until no further mass loss occurred. The changes in char morphology were studied with respect to the heating rate during charring. Scanning electron microscopy (SEM) was used with each char sample to determine the effect of heating rate. The dominant inorganic phases found in hazelnut shells were found to survive in the char. It was concluded that the high lignin content found in the char played a critical role in the decomposition mechanism. 3 refs., 2 tabs., 2 figs.

  18. Heat shock response in yeast involves changes in both transcription rates and mRNA stabilities.

    Directory of Open Access Journals (Sweden)

    Laia Castells-Roca

    Full Text Available We have analyzed the heat stress response in the yeast Saccharomyces cerevisiae by determining mRNA levels and transcription rates for the whole transcriptome after a shift from 25 °C to 37 °C. Using an established mathematical algorithm, theoretical mRNA decay rates have also been calculated from the experimental data. We have verified the mathematical predictions for selected genes by determining their mRNA decay rates at different times during heat stress response using the regulatable tetO promoter. This study indicates that the yeast response to heat shock is not only due to changes in transcription rates, but also to changes in the mRNA stabilities. mRNA stability is affected in 62% of the yeast genes and it is particularly important in shaping the mRNA profile of the genes belonging to the environmental stress response. In most cases, changes in transcription rates and mRNA stabilities are homodirectional for both parameters, although some interesting cases of antagonist behavior are found. The statistical analysis of gene targets and sequence motifs within the clusters of genes with similar behaviors shows that both transcriptional and post-transcriptional regulons apparently contribute to the general heat stress response by means of transcriptional factors and RNA binding proteins.

  19. Study of the Al-Si-X system by different cooling rates and heat treatment

    Directory of Open Access Journals (Sweden)

    Miguel Angel Suarez

    2012-10-01

    Full Text Available The solidification behavior of the Al-12.6% Si (A1, the hypereutectic Al-20%Si (A2 and the Al-20%Si-1.5% Fe-0.5%Mn (A3 (in wt. (% alloys, at different cooling rates is reported and discussed. The cooling rates ranged between 0.93 °C/s and 190 °C/s when cast in sand and copper wedge-shaped molds, respectively. A spheroidization heat treatment was carried out to the alloys in the as-cast condition at 540 °C for 11 hours and quench in water with a subsequent heat treatment at 170 °C for 5 hours with the purpose of improving the mechanical properties. The samples were characterized by optical microscopy, scanning electron microscopy and mechanically by tensile test, in order to evaluate the response of the heat treatment on the different starting microstructures and mechanical properties. It was found that alloys cooled at rates greater than 10.8 °C/s had a smaller particle size and better distribution, also showed a greater response to spheroidization heat treatment of all silicon (Si phases. The spheroidization heat treatment caused an increase in the ultimate tensile stress (UTS and elongation when compared with the alloys in the as-cast condition. The highest UTS value of 174 MPa was obtained for the (A1 alloy.

  20. Characterization of heat waves affecting mortality rates of broilers between 29 days and market age

    Directory of Open Access Journals (Sweden)

    MM Vale

    2010-12-01

    Full Text Available Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM of birds between 29 and 31 days of age. Maximum temperature humidity index (THI above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1 maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2 maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days.

  1. Average Heating Rate of Hot Atmospheres in Distant Galaxy Clusters by Radio AGN: Evidence for Continuous AGN Heating

    Science.gov (United States)

    Ma, Cheng-Jiun; McNamara, B.; Nulsen, P.; Schaffer, R.

    2011-09-01

    X-ray observations of nearby clusters and galaxies have shown that energetic feedback from AGN is heating hot atmospheres and is probably the principal agent that is offsetting cooling flows. Here we examine AGN heating in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree X-ray Cluster survey with radio sources in the NRAO VLA Sky Survey. The jet power for each radio source was determined using scaling relations between radio power and cavity power determined for nearby clusters, groups, and galaxies with atmospheres containing X-ray cavities. Roughly 30% of the clusters show radio emission above a flux threshold of 3 mJy within the central 250 kpc that is presumably associated with the brightest cluster galaxy. We find no significant correlation between radio power, hence jet power, and the X-ray luminosities of clusters in redshift range 0.1 -- 0.6. The detection frequency of radio AGN is inconsistent with the presence of strong cooling flows in 400SD, but cannot rule out the presence of weak cooling flows. The average jet power of central radio AGN is approximately 2 10^{44} erg/s. The jet power corresponds to an average heating of approximately 0.2 keV/particle for gas within R_500. Assuming the current AGN heating rate remained constant out to redshifts of about 2, these figures would rise by a factor of two. Our results show that the integrated energy injected from radio AGN outbursts in clusters is statistically significant compared to the excess entropy in hot atmospheres that is required for the breaking of self-similarity in cluster scaling relations. It is not clear that central AGN in 400SD clusters are maintained by a self-regulated feedback loop at the base of a cooling flow. However, they may play a significant role in preventing the development of strong cooling flows at early epochs.

  2. Study on release rate of latent heat in Czochralski silicon growth

    Institute of Scientific and Technical Information of China (English)

    REN Bingyan; YANG Jiankun; LI Yanlin; LIU Xiaoping; WANG Minhua

    2006-01-01

    The pulling rate in czochralski silicon (CZSi) growth is important for reducing the cost of solar cell.In this paper, double-heater, heat shield and composite argon duct system were introduced in the Ф450 mm hot zone of a Czochralski furnace.The pulling rate under different thermal system was recorded in experiments.Argon flow and temperature fields were simulated by finite element method(FEM).Experimental results and numerical simulation indicate that double-heater and composite argon duct system can enhance obviously the release rate of latent heat.In Φ 200 mm Czochralski silicon (CZSi) growth, average pulling rate can increase from 0.6 mm·min-1 in the conventional hot zone to 0.8 mm·min-1 in the modified hot zone.

  3. Heat and mass transfer rates during flow of dissociated hydrogen gas over graphite surface

    Science.gov (United States)

    Nema, V. K.; Sharma, O. P.

    1986-01-01

    To improve upon the performance of chemical rockets, the nuclear reactor has been applied to a rocket propulsion system using hydrogen gas as working fluid and a graphite-composite forming a part of the structure. Under the boundary layer approximation, theoretical predictions of skin friction coefficient, surface heat transfer rate and surface regression rate have been made for laminar/turbulent dissociated hydrogen gas flowing over a flat graphite surface. The external stream is assumed to be frozen. The analysis is restricted to Mach numbers low enough to deal with the situation of only surface-reaction between hydrogen and graphite. Empirical correlations of displacement thickness, local skin friction coefficient, local Nusselt number and local non-dimensional heat transfer rate have been obtained. The magnitude of the surface regression rate is found low enough to ensure the use of graphite as a linear or a component of the system over an extended period without loss of performance.

  4. Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity

    Energy Technology Data Exchange (ETDEWEB)

    E. Cetin; R. Gupta; B. Moghtaderi [University of Newcastle, Callaghan, NSW (Australia). Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, School of Engineering

    2005-07-01

    The knowledge of biomass char gasification kinetics has considerable importance in the design of advanced biomass gasifiers, some of which operate at high pressure. The char gasification kinetics themselves are influenced by char structure. In this study, the effects of pyrolysis pressure and heating rate on the char structure were investigated using scanning electron microscopy (SEM) analysis, digital cinematography, and surface area analysis. Char samples were prepared at pressures between 1 and 20 bar, temperatures ranging from 800 to 1000{degree}C, and heating rates between 20 and 500{degree}C/s. Our results indicate that pyrolysis conditions have a notable impact on the biomass char morphology. Pyrolysis pressure, in particular, was found to influence the size and the shape of char particles while high heating rates led to plastic deformation of particles (i.e. melting) resulting in smooth surfaces and large cavities. The global gasification reactivities of char samples were also determined using thermogravimetric analysis (TGA) technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. 22 refs., 8 figs., 2 tabs.

  5. Characterizing the effects of scale and heating rate on micro-scale explosive ignition criteria.

    Energy Technology Data Exchange (ETDEWEB)

    Hafenrichter, Everett Shingo; Pahl, Robert J.

    2005-01-01

    Laser diode ignition experiments were conducted in an effort to characterize the effects of scale and heating rate on micro-scale explosive ignition criteria. Over forty experiments were conducted with various laser power densities and laser spot sizes. In addition, relatively simple analytical and numerical calculations were performed to assist with interpretation of the experimental data and characterization of the explosive ignition criteria.

  6. Heating Rate Effect on the Activation of Viscoelastic Relaxation in Silicate Glasses

    Science.gov (United States)

    Naji, Mohamed; Piazza, Francesco; Guimbretière, Guillaume; Canizarès, Aurèlien; Ory, Sandra; Vaills, Yann

    Here we present a direct investigation of the heating rate effect on structural relaxation of sodium silicate glass near the glass transition by means of differential scanning calorimetry, and show the sensitivity of Brillouin light spectroscopy to the dynamic of structural relaxation in the medium range order (∼100 nm).

  7. The influence of SPS heating rates on the synthesis reaction of tantalum diboride

    Directory of Open Access Journals (Sweden)

    Jolanta Laszkiewicz-Łukasik

    2016-07-01

    Full Text Available TaB2 is a material from the Ultra High Temperature Ceramics group and is rather unexplored because it is difficult to procure the raw materials and to densify TaB2. Using SPS technique to realize reactive sintering processes of powders mixture according to the reaction Ta + 2B → TaB2 makes it possible to achieve TaB2 in one technological step. The aim of the study was to determine the influence of heating rates on the synthesis reaction and on the multistage densification mechanisms during SPS processes. The mixture was sintered at constant parameters of 2200 °C, 48 MPa for 5 min with the usage of heating rates from 50 °C/min up to 400 °C/min. The densification processes were studied through analyzing the shrinkage of powder compacts during SPS (Spark Plasma Sintering processes. The comparison of the densification curves indicates that the reactions do not proceed completely at slow heating rates. Namely, too low heating rates contribute to the sintering of tantalum before the synthesis reaction and demonstrate the presence of boron in liquid state. The best material obtained in this study has Young's modulus 571 GPa, Vickers hardness 20.7 GPa (HV1 and indentation fracture toughness KIC 4.7 MPa m1/2.

  8. Respiration Rate Predictive Equation and Effective Heat Stress Relief Ways for Hanwoo Steers

    OpenAIRE

    Gutierrez, Winson-Montanez; Oh, Taek-Kuen; Kim, Dong-Hyeok; Lee, Jin-Ju; Kim, Suk; Min, Wong; Lee, Seung-Joo; Kim, Byeong-Woo; Chang, Hong-Hee; Chikushi, Jiro

    2012-01-01

    Normalizing respiration rate in heat–stress challenged cattle during summer season is very important. In this study, we investigated the contribution of different thermal factors such as skin temperature, dew–point temperature, solar radiation, dry–bulb temperature and wind speed on its influence to the respiration rate dynamics of 45 Hanwoo steers in 2010. Secondly, the heat insulation efficiencies of the three kinds of roofing materials such as sandwich panel (SP), master panel (MP), and fi...

  9. Effect of low and high heating rates on reaction path of Ni(V)/Al multilayer

    Energy Technology Data Exchange (ETDEWEB)

    Maj, Łukasz, E-mail: l.maj@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Kraków (Poland); Morgiel, Jerzy; Szlezynger, Maciej [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Kraków (Poland); Bała, Piotr; Cios, Grzegorz [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, 30 Kawiory St., 30-055 Kraków (Poland)

    2017-06-01

    The effect of heating rates of Ni(V)/Al NanoFoils{sup ®} was investigated with transmission electron microscopy (TEM). The Ni(V)/Al were subjected to heating by using differential scanning calorimetry (DSC), in-situ TEM or electric pulse. Local chemical analysis was carried out using energy dispersive X-ray spectroscopy (EDS). Phase analysis was done with X-ray diffractions (XRD) and selected area electron diffractions (SAED). The experiments showed that slow heating in DSC results in development of separate exothermic effects at ∼230 °C, ∼280 °C and ∼390 °C, corresponding to precipitation of Al{sub 3}Ni, Al{sub 3}Ni{sub 2} and NiAl phases, respectively, i.e. like in vanadium free Ni/Al multilayers. Further heating to 700 °C allowed to obtain a single phase NiAl foil. The average grain size (g.s.) of NiAl phase produced in the DSC heat treated foil was comparable with the Ni(V)/Al multilayer period (∼50 nm), whereas in the case of reaction initiated with electric pulse the g.s. was in the micrometer range. Upon slow heating vanadium tends to segregate to zones parallel to the original multilayer internal interfaces, while in SHS process vanadium-rich phases precipitates at grain boundaries of the NiAl phase. - Highlights: • Peaks in DSC heating of Ni(V)/Al were explained by in-situ TEM observations. • Nucleation of Al{sub 3}Ni, Al{sub 3}Ni{sub 2} and NiAl at slow heating of Ni(V)/Al was documented. • Near surface NiAl obtained from NanoFoil show Ag precipitates at grain boundaries.

  10. The influence of spectral solar irradiance data on stratospheric heating rates during the 11 year solar cycle

    OpenAIRE

    Oberländer, S.; Langematz, U.; Matthes, Katja; Kunze, M; A. Kubin; J. Harder; N. A. Krivova; Solanki, S. K.; J. Pagaran; Weber, M.

    2012-01-01

    Heating rate calculations with the FUBRad shortwave (SW) radiation parameterization have been performed to examine the effect of prescribed spectral solar fluxes from the NRLSSI, MPS and IUP data sets on SW heating rates over the 11 year solar cycle 22. The corresponding temperature response is derived from perpetual January General Circulation Model (GCM) simulations with prescribed ozone concentrations. The different solar flux input data sets induce clear differences in SW heating rates at...

  11. On-line corrosion monitoring in geothermal district heating systems. I. General corrosion rates

    DEFF Research Database (Denmark)

    Richter, S.; Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.

    2006-01-01

    General corrosion rates in the geothermal district heating systems in Iceland are generally low, of the magnitude 1 mu m/y. The reason is high pH (9.5), low-conductivity (200 mu m/y) and negligible dissolved oxygen. The geothermal hot water is either used directly from source or to heat up cold...... ground water. The fluid naturally contains sulphide, which helps keeping the fluid oxygen-free but complicates the electrochemical environment. In this research on-line techniques for corrosion monitoring were tested and evaluated in this medium. Electrochemical methods worked well as long as frequency...

  12. Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.

    2008-01-01

    Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...

  13. The Effect of Particle Concentration on the Heating Rate of Ferrofluids for Magnetic Hyperthermia

    Directory of Open Access Journals (Sweden)

    Malaescu I.

    2015-12-01

    Full Text Available The complex magnetic susceptibility χ(f = χ′(f - i χ″(f, of a ferrofluid sample with magnetite particles dispersed in kerosene and stabilized with oleic acid, over the range 0.1 GHz to 6 GHz, was determined. The initial sample has been successively diluted with kerosene (with a dilution rate of 2/3, thus obtaining further three samples. Using the complex magnetic susceptibility measurements of each sample, the frequency field and particle concentration dependencies of the heating rate of the ferrofluid samples, were analyzed. The results show the possibility of using the heating rate of ferrofluid samples with different particle concentrations, in hyperthermia applications.

  14. Evaluation of induced activity, decay heat and dose rate distribution after shutdown in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Koichi [Hitachi Ltd., Ibaraki (Japan). Hitachi Research Lab.; Satoh, Satoshi; Hayashi, Katsumi; Yamada, Koubun; Takatsu, Hideyuki; Iida, Hiromasa

    1997-03-01

    Induced activity, decay heat and dose rate distributions after shutdown were estimated for 1MWa/m{sup 2} operation in ITER. The activity in the inboard blanket one day after shutdown is 1.5x10{sup 11}Bq/cm{sup 3}, and the average decay heating rate 0.01w/cm{sup 3}. The dose rate outside the 120cm thick concrete biological shield is two order higher than the design criterion of 5{mu}Sv/h. This indicates that the biological shield thickness should be enhanced by 50cm in concrete, that is, total thickness 170cm for workers to enter the reactor room and to perform maintenance. (author)

  15. Heat Source Neutron Emission Rate Reduction Studies - Water Induced HF Liberation

    Science.gov (United States)

    Matonic, John; Brown, John; Foltyn, Liz; Garcia, Lawrence; Hart, Ron; Herman, David; Huling, Jeff; Pansoy-Hjelvik, M. E. Lisa; Sandoval, Fritz; Spengler, Diane

    2004-02-01

    Plutonium-238 oxide (238PuO2) is used in the fabrication of general purpose heat sources (GPHS) or light-weight radioisotope heater units (LWRHUs). The heat sources supply the thermal energy used in radioisotope thermoelectric generators to power spacecraft for deep space missions and to heat critical components in the cold environs of space. Los Alamos National Laboratory has manufactured heat sources for approximately two decades. The aqueous purification of 238PuO2 is required, due to rigorous total Pu-content, actinide and non-actinide metal impurity, and neutron emission rate specifications. The 238PuO2 aqueous purification process is a new capability at Los Alamos National Laboratory as previously, aqueous purified 238PuO2 occurred at other DOE complexes. The Pu-content and actinide and non-actinide metal impurity specifications are met well within specification in the Los Alamos process, though reduction in neutron emission rates have been challenging. High neutron emission rates are typically attributed to fluoride content in the oxide. The alpha decay from 238Pu results in α,n reactions with light elements such as 17O, 18O, and 19F resulting in high neutron emission rates in the purified 238PuO2. Simple 16O-exchange takes care of the high NER due to 17O, and 18O. A new method to reduce the NER due to 19F in the purified 238PuO2 is presented in this paper. The method involves addition of water to purified 238PuO2, followed by heating to remove the water and liberating fluoride as HF.

  16. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters.

    Science.gov (United States)

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915 measured samples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rate and heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08.

  17. Effects of Adiabatic Heating on the High Strain Rate Deformation of Polymer Matrix Composites

    Science.gov (United States)

    Sorini, Chris; Chattopadhyay, Aditi; Goldberg, Robert K.

    2017-01-01

    Polymer matrix composites (PMCs) are increasingly being used in aerospace structures that are expected to experience complex dynamic loading conditions throughout their lifetime. As such, a detailed understanding of the high strain rate behavior of the constituents, particularly the strain rate, temperature, and pressure dependent polymer matrix, is paramount. In this paper, preliminary efforts in modeling experimentally observed temperature rises due to plastic deformation in PMCs subjected to dynamic loading are presented. To this end, an existing isothermal viscoplastic polymer constitutive formulation is extended to model adiabatic conditions by incorporating temperature dependent elastic properties and modifying the components of the inelastic strain rate tensor to explicitly depend on temperature. It is demonstrated that the modified polymer constitutive model is capable of capturing strain rate and temperature dependent yield as well as thermal softening associated with the conversion of plastic work to heat at high rates of strain. The modified constitutive model is then embedded within a strength of materials based micromechanics framework to investigate the manifestation of matrix thermal softening, due to the conversion of plastic work to heat, on the high strain rate response of a T700Epon 862 (T700E862) unidirectional composite. Adiabatic model predictions for high strain rate composite longitudinal tensile, transverse tensile, and in-plane shear loading are presented. Results show a substantial deviation from isothermal conditions; significant thermal softening is observed for matrix dominated deformation modes (transverse tension and in-plane shear), highlighting the importance of accounting for the conversion of plastic work to heat in the polymer matrix in the high strain rate analysis of PMC structures.

  18. Effects of Heating Rate on the Process Parameters of Superplastic Forming for Zr55Cu30Al10Ni5

    Institute of Scientific and Technical Information of China (English)

    YANG Fan; SHI Tielin; LIAO Guanglan

    2014-01-01

    We investigated the effects of heating rate on the process parameters of superplastic forming for Zr55Cu30Al10Ni5 by differential scanning calorimetry. The continuous heating and isothermal annealing analyses suggested that the temperatures of glass transition and onset crystallization are heating rate-dependent in the supercooled liquid region. Then, the time-temperature-transformation diagram under different heating rates indicates that increasing the heating rate can lead to an increase of the incubation time at the same anneal temperature in the supercooled liquid region. Based on the Arrhenius relationship, we discovered that the incubation time increases by 1.08-1.11 times with double increase of the heating rate at the same anneal temperature, and then verified it by the data of literatures and the experimental results. The obtained curve of the max available incubation time reveals that the incubation time at a certain anneal temperature in the supercooled liquid region is not infinite, and will increase with increasing heating rate until this temperature shifts out of the supercooled liquid region because of exceeding critical heating rate. It is concluded that heating rate must be an important processing parameter of superplastic forming for Zr55Cu30Al10Ni5.

  19. EXPERIMENTAL STUDY OF MEASUREMENT FOR DISSIPATION RATE SCALING EXPONENT IN HEATED WALL TURBULENCE

    Institute of Scientific and Technical Information of China (English)

    姜楠; 王玉春; 舒玮; 王振东

    2002-01-01

    Experimental investigations have been devoted to the study of scaling law of coarse-grained dissipation rate structure function for velocity and temperature fluctuation of non-isotropic and inhomogeneous turbulent flows at moderate Reynolds number. Much attention has been paid to the case of turbulent boundary layer, which is typically the nonistropic and inhomogeneous trubulence because of the dynamically important existence of organized coherent structure burst process in the near wall region. Longitudinal velocity and temperature have been measured at different vertical positions in turbulent boundary layer over a heated and unheated flat plate in a wind tunnel using hot wire anemometer. The influence of non-isotropy and inhomogeneity and heating the wall on the scaling law of the dissipation rate structure function is studied because of the existence of organized coherent structure burst process in the near wall region. The scaling law of coarse-grained dissipation rate structure function is found to be independent of the mean velocity shear strain and the heating wall boundary condition. The scaling law of the dissipation rate structure function is verified to be in agreement with the hierarchical structure model that has been verified valid for isotropic and homogeneous turbulence.

  20. Scaling of heat production by thermogenic flowers: limits to floral size and maximum rate of respiration.

    Science.gov (United States)

    Seymour, Roger S

    2010-09-01

    Effect of size of inflorescences, flowers and cones on maximum rate of heat production is analysed allometrically in 23 species of thermogenic plants having diverse structures and ranging between 1.8 and 600 g. Total respiration rate (, micromol s(-1)) varies with spadix mass (M, g) according to in 15 species of Araceae. Thermal conductance (C, mW degrees C(-1)) for spadices scales according to C = 18.5M(0.73). Mass does not significantly affect the difference between floral and air temperature. Aroids with exposed appendices with high surface area have high thermal conductance, consistent with the need to vaporize attractive scents. True flowers have significantly lower heat production and thermal conductance, because closed petals retain heat that benefits resident insects. The florets on aroid spadices, either within a floral chamber or spathe, have intermediate thermal conductance, consistent with mixed roles. Mass-specific rates of respiration are variable between species, but reach 900 nmol s(-1) g(-1) in aroid male florets, exceeding rates of all other plants and even most animals. Maximum mass-specific respiration appears to be limited by oxygen delivery through individual cells. Reducing mass-specific respiration may be one selective influence on the evolution of large size of thermogenic flowers.

  1. Torrefaction of invasive alien plants: Influence of heating rate and other conversion parameters on mass yield and higher heating value.

    Science.gov (United States)

    Mundike, Jhonnah; Collard, François-Xavier; Görgens, Johann F

    2016-06-01

    With the aim of controlling their proliferation, two invasive alien plants, Lantana camara (LC) and Mimosa pigra (MP), both widespread in Africa, were considered for torrefaction for renewable energy applications. Using thermogravimetric analysis, the influence of heating rate (HR: 2.18-19.82°Cmin(-1)) together with variable temperature and hold time on char yield and HHV (in a bomb calorimeter) were determined. Statistically significant effects of HR on HHV with optima at 10.5°Cmin(-1) for LC and 20°Cmin(-1) for MP were obtained. Increases of HHV up to 0.8MJkg(-1) or energy yield greater than 10%, together with a 3-fold reduction in torrefaction conversion time could be achieved by optimisation of HR. Analysis of the torrefaction volatiles by TG-MS showed that not only hemicelluloses, but also lignin conversion, could influence the optimum HR value.

  2. NAEP Fourth-, Eighth-, and Twelfth-Grade Reading Scores by Gender: 2005, 2007, 2009, 2011, 2013

    Science.gov (United States)

    Klecker, Beverly M.

    2014-01-01

    This paper describes a secondary analysis of the National Assessment of Educational Progress (NAEP) reading scores by gender. Data were national public 4th- and 8th-grade reading scores from composite and subscales for 2005, 2007, 2009, 2011, and 2013. Twelfth-grade scores for composite and literary experience from 2005, 2009, and 2013 and gain…

  3. 76 FR 79754 - Twelfth Meeting: RTCA Special Committee 220, Automatic Flight Guidance and Control

    Science.gov (United States)

    2011-12-22

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 220, Automatic Flight Guidance and Control AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION... Return to general plenary meeting Review of WG 2 status--progress, issues and plan Review of WG 3...

  4. 78 FR 16031 - Twelfth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...

    Science.gov (United States)

    2013-03-13

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium Size AGENCY: Federal Aviation Administration (FAA), U.S... Lithium Battery and Battery Systems--Small and Medium Size. SUMMARY: The FAA is issuing this notice to...

  5. Influence of microwave heating on liquid-liquid phase inversion and temperature rates for immiscible mixtures.

    Science.gov (United States)

    Kennedy, Alvin; Tadesse, Solomon; Nunes, Janine; Reznik, Aron

    2011-01-01

    Time dependencies of component temperatures for mixtures of immiscible liquids during microwave heating were studied for acetonitrile-cyclohexane and water-toluene. For the first time, we report microwave induced liquid-liquid phase inversion for acetonitrile-cyclohexane mixture: acetonitrile layer was initially at the bottom of the mixture, after 10 sec of microwave heating its density decreased and it inverted to the top of the mixture for the remainder of the microwave heating. This phase inversion could not be achieved by conventional radiant heating. The maximum rate of temperature growth for the polar component of the mixtures was 2 - 5 times larger than for the non-polar component. This suggests that microwave energy is absorbed by polar liquids (water or acetonitrile) and heat is transferred into the non-polar liquid (toluene or cyclohexane) in the mixture by conduction (in case of cyclohexane) or conduction and convection (in case of toluene). Comparison between experimental data and semi-empirical mathematical models, proposed in [Kennedy et at., 2009] showed good correlation. Average relative error between theoretical and experimental results did not exceed 7%. These results can be used to model the temperature kinetics of components for other multiphase mixtures.

  6. A Surface Heat Disturbance Method for Measuring Local TIssue Blood Perfusion Rate

    Institute of Scientific and Technical Information of China (English)

    PengJianshu; TianYongquan

    1996-01-01

    A non-damage method for measuring local tissue blood perfusion rate by surface heat disturbance and its two special embodiments for realizing this measurement are presented in this paper,In the derivation of mathematical model,the Pennes equation is used,and two parameters which are very diffcult to be known-the arterial blood temperature Ta and the metabolic heat generation rate qm,have been eliminated.So if has provided a feasible basis for application.In this paper,the performance and the adaptable condition of the measurement method and its structure peculiarities are discussed over a wide variety of parameters.Moreover,the effectiveness of the measurement method has been demonstrated by means of the quantitative measurement of tissue in vitro,the comparative measurement of animal under artificial perfusion and the dependence measurement in human body.

  7. Heating rate and spin flip lifetime due to near field noise in layered superconducting atom chips

    CERN Document Server

    Fermani, Rachele; Zhang, Bo; Lim, Michael J; Dumke, Rainer

    2009-01-01

    We theoretically investigate the heating rate and spin flip lifetimes due to near field noise for atoms trapped close to layered superconducting structures. In particular, we compare the case of a gold layer deposited above a superconductor with the case of a bare superconductor. We study a niobium-based and a YBCO-based chip. For both niobium and YBCO chips at a temperature of 4.2 K, we find that the deposition of the gold layer can have a significant impact on the heating rate and spin flip lifetime, as a result of the increase of the near field noise. At a chip temperature of 77 K, this effect is less pronounced for the YBCO chip.

  8. Fissure formation in coke. 2: Effect of heating rate, shrinkage and coke strength

    Energy Technology Data Exchange (ETDEWEB)

    D.R. Jenkins; M.R. Mahoney [CSIRO, North Ryde, NSW (Australia). Mathematical and Information Sciences

    2010-07-15

    We investigate the effects of the heating rate, coke shrinkage and coke breakage strength upon the fissure pattern developed in a coke oven charge during carbonisation. This is done principally using a mechanistic model of the formation of fissures, which considers them to be an array of equally spaced fissures, whose depth follows a 'period doubling' pattern based upon the time history of the fissures. The model results are compared with pilot scale coke oven experiments. The results show that the effect of heating rate on the fissure pattern is different to the effect of coke shrinkage, while the effect of coke breakage strength on the pattern is less pronounced. The results can be seen in both the shape and size of resulting coke lumps after stabilisation. The approach gives the opportunity to consider means of controlling the carbonisation process in order to tune the size of the coke lumps produced. 7 refs., 18 figs., 4 tabs.

  9. Heat and mass transfer analogies for evaporation models at high evaporation rate

    OpenAIRE

    Trontin, P.; Villedieu, P.

    2014-01-01

    International audience; In the framework of anti and deicing applications, heated liquid films can appear above the ice thickness, or directly above the wall. Then, evaporation plays a major role in the Messinger balance and evaporated mass has to be predicted accurately. Unfortunately, it appears that existing models under-estimate evaporation at high temperature. In this study, different evaporation models at high evaporation rates are studied. The different hypothesis on which these models...

  10. Additive Effects of Heating and Exercise on Baroreflex Control of Heart Rate in Healthy Males.

    Science.gov (United States)

    Peçanha, Tiago; Forjaz, Claudia Lucia de Moraes; Low, David Andrew

    2017-08-31

    This study assessed the additive effects of passive heating and exercise on cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV). Twelve healthy young men (25±1 yrs, 23.8±0.5 kg/m(2)) randomly underwent two experimental sessions: heat stress (HS; whole-body heat stress using a tube-lined suit to increase core temperature by ~1°C) and normothermia (NT). Each session was composed of a: pre-intervention rest (REST1); HS or NT interventions; post-intervention rest (REST2); and 14 min of cycling exercise [7 min at 40%HRreserve (EX1) and 7 min at 60%HRreserve (EX2)]. Heart rate and finger blood pressure were continuously recorded. cBRS was assessed using the sequence (cBRSSEQ) and transfer function (cBRSTF) methods. HRV was assessed using the indices SDNN (standard deviation of RR intervals) and RMSSD (root mean square of successive RR intervals). cBRS and HRV were not different between sessions during EX1 and EX2 (i.e. matched heart rate conditions: EX1=116±3 vs. 114±3, EX2=143±4 vs. 142±3 bpm; but different workloads: EX1=50±9 vs. 114±8, EX2=106±10 vs. 165±8 Watts; for HS and NT, respectively; Pheart rates), cBRS and HRV were significantly reduced in HS (cBRSSEQ = 1.6±0.3 vs. 0.6±0.1 ms/mmHg, Pexercise does not affect cBRS and HRV. Alternatively, in workload-matched conditions, the addition of heat to exercise results in reduced cBRS and HRV compared to exercise in normothermia. Copyright © 2017, Journal of Applied Physiology.

  11. Influence of Heating Rate on Double Reversible Transformation in CuZnAlMnNi Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The influence of heating rate on double reversible transformation in CuZnA1MnNi shape memory alloy was investigated by differential scanning calorimetry. It was found that rapid heating inhibits X→M transformation but is fa vorable to the reverse martensite transformation, giving rise to the approach of the two transformation peaks. With the decrease of heating rate, the two transformation peaks separate gradually.

  12. Influence of drying temperature, water content, and heating rate on gelatinization of corn starches.

    Science.gov (United States)

    Altay, Filiz; Gunasekaran, Sundaram

    2006-06-14

    The gelatinization properties of starch extracted from corn and waxy corn dried at different temperatures were determined at various water contents and heating rates by differential scanning calorimetry. All gelatinization transition temperatures increased with drying temperature and heating rate. Onset and peak temperatures remained relatively constant, whereas end temperature decreased in the presence of excess water. The gelatinization enthalpy (deltaH(g)) of corn starch decreased with drying temperature at 50% water; however, it remained constant for waxy corn starch. The effects of water content and heating rate on deltaH(g) were dependent on each other. The minimum water levels required for gelatinization of starch extracted from corn dried at 20 and 100 degrees C are 21 and 29%, respectively. The activation energy (E(a)) was calculated using an Arrhenius-type equation and two first-order models; the degree of conversion (alpha) was predicted using a newly proposed model that produced good results for both E(a) and alpha.

  13. The influence of the magnetic field on the heat transfer rate in rotating spherical shells

    Science.gov (United States)

    Cabello, Ares; Avila, Ruben

    2016-11-01

    Studies of the relationship between natural convection and magnetic field generation in spherical annular geometries with rotation are essential to understand the internal dynamics of the terrestrial planets. In such studies it is important to calculate and analyze the heat transfer rate at the inner and the outer spheres that confine the spherical gap. Previous investigations indicate that the magnetic field has a stabilizing effect on the onset of the natural convection, reduces the intensity of convection and modifies the flow patterns. However so far it is still unclear how the magnetic field change the heat transfer rate behaviour. We investigate the heat transfer rate (Nu) in a rotating spherical gap with a self gravity field varying linearly with radius, and its relation with the intensity of the magnetic field induced by the geodynamo effect. The Boussinesq fluid equations are solved by using a spectral element method (SEM). To avoid the singularity at the poles, the cubed-sphere algorithm is used to generate the spherical mesh. Several cases are simulated in which the Rayleigh number, the magnetic Reynolds number and the Taylor number are the variable parameters. The flow patterns, the temperature distribution and the Nusselt numbers at both spheres are calculated. Special thanks to DGAPA-UNAM Project PAPIIT IN11731, sponsor of this investigation.

  14. Effect of heating and cooling rate on the kinetics of allotropic phase changes in uranium: A differential scanning calorimetry study

    Energy Technology Data Exchange (ETDEWEB)

    Rai, Arun Kumar [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India); Raju, S. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India)], E-mail: sraju@igcar.gov.in; Jeyaganesh, B.; Mohandas, E. [Physical Metallurgy Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India); Sudha, R.; Ganesan, V. [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam 603 102, Tamilnadu (India)

    2009-01-01

    The kinetic aspects of allotropic phase changes in uranium are studied as a function of heating/cooling rate in the range 10{sup 0}-10{sup 2} K min{sup -1} by isochronal differential scanning calorimetry. The transformation arrest temperatures revealed a remarkable degree of sensitivity to variations of heating and cooling rate, and this is especially more so for the transformation finish (T{sub f}) temperatures. The results obtained for the {alpha} {yields} {beta} and {beta} {yields} {gamma} transformations during heating confirm to the standard Kolmogorov-Johnson-Mehl-Avrami (KJMA) model for a nucleation and growth mediated process. The apparent activation energy Q{sub eff} for the overall transformation showed a mild increase with increasing heating rate. In fact, the heating rate normalised Arrhenius rate constant, k/{beta} reveals a smooth power law decay with increasing heating rate ({beta}). For the {alpha} {yields} {beta} phase change, the observed DSC peak profile for slower heating rates contained a distinct shoulder like feature, which however is absent in the corresponding profiles found for higher heating rates. The kinetics of {gamma} {yields} {beta} phase change on the other hand, is best described by the two-parameter Koistinen-Marburger empirical relation for the martensitic transformation.

  15. Conception rate of artificially inseminated Holstein cows affected by cloudy vaginal mucus, under intense heat conditions

    Directory of Open Access Journals (Sweden)

    Miguel Mellado

    2015-06-01

    Full Text Available The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services, raised under intense heat (mean annual temperature of 22°C, at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses. The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1-21.7%. The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%. Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.

  16. In situ synchrotron IR study relating temperature and heating rate to surface functional group changes in biomass.

    Science.gov (United States)

    Kirtania, Kawnish; Tanner, Joanne; Kabir, Kazi Bayzid; Rajendran, Sharmen; Bhattacharya, Sankar

    2014-01-01

    Three types of woody biomass were investigated under pyrolysis condition to observe the change in the surface functional groups by Fourier transform infrared (FTIR) technique with increasing temperature under two different (5 and 150°C/min) heating rates. The experiments were carried out in situ in the infrared microscopy beamline (IRM) of the Australian Synchrotron. The capability of the beamline made it possible to focus on single particles to obtain low noise measurements without mixing with KBr. At lower heating rate, the surface functional groups were completely removed by 550°C. In case of higher heating rate, a delay was observed in losing the functional groups. Even at a high temperature, significant number of functional groups was retained after the higher heating rate experiments. This implies that at considerably high heating rates typical of industrial reactors, more functional groups will remain on the surface.

  17. Statistical properties of Joule heating rate, electric field and conductances at high latitudes

    Directory of Open Access Journals (Sweden)

    A. T. Aikio

    2009-07-01

    Full Text Available Statistical properties of Joule heating rate, electric field and conductances in the high latitude ionosphere are studied by a unique one-month measurement made by the EISCAT incoherent scatter radar in Tromsø (66.6 cgmlat from 6 March to 6 April 2006. The data are from the same season (close to vernal equinox and from similar sunspot conditions (about 1.5 years before the sunspot minimum providing an excellent set of data to study the MLT and Kp dependence of parameters with high temporal and spatial resolution.

    All the parameters show a clear MLT variation, which is different for low and high Kp conditions. Our results indicate that the response of morning sector conductances and conductance ratios to increased magnetic activity is stronger than that of the evening sector. The co-location of Pedersen conductance maximum and electric field maximum in the morning sector produces the largest Joule heating rates 03–05 MLT for Kp≥3. In the evening sector, a smaller maximum occurs at 18 MLT. Minimum Joule heating rates in the nightside are statistically observed at 23 MLT, which is the location of the electric Harang discontinuity.

    An important outcome of the paper are the fitted functions for the Joule heating rate as a function of electric field magnitude, separately for four MLT sectors and two activity levels (Kp<3 and Kp≥3. In addition to the squared electric field, the fit includes a linear term to study the possible anticorrelation or correlation between electric field and conductance. In the midday sector, positive correlation is found as well as in the morning sector for the high activity case. In the midnight and evening sectors, anticorrelation between electric field and conductance is obtained, i.e. high electric fields are associated with low conductances. This is expected to occur in the return current regions adjacent to

  18. Molecular dynamics study on the effect of boundary heating rate on the phase change characteristics of thin film liquid

    Science.gov (United States)

    Hasan, Mohammad Nasim; Morshed, A. K. M. Monjur; Rabbi, Kazi Fazle; Haque, Mominul

    2016-07-01

    In this study, theoretical investigation of thin film liquid phase change phenomena under different boundary heating rates has been conducted with the help of molecular dynamics simulation. To do this, the case of argon boiling over a platinum surface has been considered. The study has been conducted to get a better understanding of the nano-scale physics of evaporation/boiling for a three phase system with particular emphasis on the effect of boundary heating rate. The simulation domain consisted of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system was brought to an equilibrium state at 90K with the help of equilibrium molecular dynamics and then the temperature of the bottom wall was increased to a higher temperature (250K/130K) over a finite heating period. Depending on the heating period, the boundary heating rate has been varied in the range of 1600×109 K/s to 8×109 K/s. The variations of argon region temperature, pressure, net evaporation number with respect to time under different boundary heating rates have been determined and discussed. The heat fluxes normal to platinum wall for different cases were also calculated and compared with theoretical upper limit of maximum possible heat transfer to elucidate the effect of boundary heating rate.

  19. Effect of Heating Rate on Electromechanical Properties ofPNN–PZT Solid Solution

    Directory of Open Access Journals (Sweden)

    Virendra Singh

    2007-01-01

    Full Text Available Lead nickel niobate–lead zirconate titanate (Pb(Ni1/3Nb2/30.5 –Pb(Zr0.15Ti0.35O3, (PNN-PZTsolid solution was synthesised by columbite  process. Samples sintered at various heating ratesfor 4 h holding and their effect on electromechanical properties have been studied. When heatingrate was 8 °C/min from room temperature to 900 °C and holding for 4 h at 1280 °C, highest relativepermittivity and piezoelectric charge constant were observed, whereas heating rate of 3.5° C/min and holding for 4 h at 1280 °C have shown inferior electromechanical properties and graincoarsening. The piezoelectric charge constant (d33 ~612 pC/N and dielectric constant (e~ 5950observed in fast heating rate specimen as against to d33~ 137 pC/N and e~4294. XRD result showsthe formation of pyrochlore-free perovskite phase. Fine grains were observed  for fast heatingrate specimens.

  20. Extension of the master sintering curve for constant heating rate modeling

    Science.gov (United States)

    McCoy, Tammy Michelle

    The purpose of this work is to extend the functionality of the Master Sintering Curve (MSC) such that it can be used as a practical tool for predicting sintering schemes that combine both a constant heating rate and an isothermal hold. Rather than just being able to predict a final density for the object of interest, the extension to the MSC will actually be able to model a sintering run from start to finish. Because the Johnson model does not incorporate this capability, the work presented is an extension of what has already been shown in literature to be a valuable resource in many sintering situations. A predicted sintering curve that incorporates a combination of constant heating rate and an isothermal hold is more indicative of what is found in real-life sintering operations. This research offers the possibility of predicting the sintering schedule for a material, thereby having advanced information about the extent of sintering, the time schedule for sintering, and the sintering temperature with a high degree of accuracy and repeatability. The research conducted in this thesis focuses on the development of a working model for predicting the sintering schedules of several stabilized zirconia powders having the compositions YSZ (HSY8), 10Sc1CeSZ, 10Sc1YSZ, and 11ScSZ1A. The compositions of the four powders are first verified using x-ray diffraction (XRD) and the particle size and surface area are verified using a particle size analyzer and BET analysis, respectively. The sintering studies were conducted on powder compacts using a double pushrod dilatometer. Density measurements are obtained both geometrically and using the Archimedes method. Each of the four powders is pressed into ¼" diameter pellets using a manual press with no additives, such as a binder or lubricant. Using a double push-rod dilatometer, shrinkage data for the pellets is obtained over several different heating rates. The shrinkage data is then converted to reflect the change in relative

  1. High-rate laser metal deposition of Inconel 718 component using low heat-input approach

    Science.gov (United States)

    Kong, C. Y.; Scudamore, R. J.; Allen, J.

    Currently many aircraft and aero engine components are machined from billets or oversize forgings. This involves significant cost, material wastage, lead-times and environmental impacts. Methods to add complex features to another component or net-shape surface would offer a substantial cost benefit. Laser Metal Deposition (LMD), currently being applied to the repair of worn or damaged aero engine components, was attempted in this work as an alternative process route, to build features onto a base component, because of its low heat input capability. In this work, low heat input and high-rate deposition was developed to deposit Inconel 718 powder onto thin plates. Using the optimised process parameters, a number of demonstrator components were successfully fabricated.

  2. Stage-specific heat effects: timing and duration of heat waves alter demographic rates of a global insect pest.

    Science.gov (United States)

    Zhang, Wei; Rudolf, Volker H W; Ma, Chun-Sen

    2015-12-01

    The frequency and duration of periods with high temperatures are expected to increase under global warming. Thus, even short-lived organisms are increasingly likely to experience periods of hot temperatures at some point of their life-cycle. Despite recent progress, it remains unclear how various temperature experiences during the life-cycle of organisms affect demographic traits. We simulated hot days (daily mean temperature of 30 °C) increasingly experienced under field conditions and investigated how the timing and duration of such hot days during the life cycle of Plutella xylostella affects adult traits. We show that hot days experienced during some life stages (but not all) altered adult lifespan, fecundity, and oviposition patterns. Importantly, the effects of hot days were contingent on which stage was affected, and these stage-specific effects were not always additive. Thus, adults that experience different temporal patterns of hot periods (i.e., changes in timing and duration) during their life-cycle often had different demographic rates and reproductive patterns. These results indicate that we cannot predict the effects of current and future climate on natural populations by simply focusing on changes in the mean temperature. Instead, we need to incorporate the temporal patterns of heat events relative to the life-cycle of organisms to describe population dynamics and how they will respond to future climate change.

  3. Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

    Science.gov (United States)

    Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

    2016-06-01

    Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

  4. Twelfth Semiannual Report of the Commission to the Congress. Major Activities in the Atomic Energy Programs, January - June 1952

    Energy Technology Data Exchange (ETDEWEB)

    Dean, Gordon

    1952-07-01

    The document represents the twelfth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1952.

  5. The influence of heating rate on superconducting characteristics of MgB{sub 2} obtained by spark plasma sintering technique

    Energy Technology Data Exchange (ETDEWEB)

    Aldica, G. [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania); Burdusel, M. [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania); Faculty of Materials Science and Engineering, University ’Politehnica’ of Bucharest, Splaiul Independentei 313, 060042 Bucharest (Romania); Popa, S.; Enculescu, M.; Pasuk, I. [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania); Badica, P., E-mail: badica2003@yahoo.com [National Institute of Materials Physics, Atomistilor 105bis, 077125 Magurele (Romania)

    2015-12-15

    Highlights: • MgB{sub 2} was obtained by ex-situ spark plasma sintering for different heating rates. • Heating rates were 20–475 °C/min: the optimum heating rate is ∼100 °C/min. • For 100 °C/min, J{sub c0}, H{sub irr} and (J{sub c0} x μ{sub 0}H{sub irr}) have maximum values. • For 100 °C/min, macro flux jumps are partially suppressed at 5 K. • Grain boundaries are modified depending on the heating rate. - Abstract: Superconducting bulks of MgB{sub 2} were obtained by the Spark Plasma Sintering (SPS) technique. Different heating rates of 20, 100, 235, 355, and 475 °C/min were used. Samples have high density, above 95%. The onset critical temperature T{sub c}, is about 38.8 K. There is an optimum heating rate of ∼100 °C/min to maximize the critical current density J{sub c0}, the irreversibility field H{sub irr}, the product (J{sub c0} x μ{sub 0}H{sub irr}), and to partially avoid formation of undesirable flux jumps at low temperatures. Significant microstructure differences were revealed for samples processed with low and high heating rates in respect to grain boundaries.

  6. Calculations of Solar Shortwave Heating Rates due to Black Carbon and Ozone Absorption Using in Situ Measurements

    Science.gov (United States)

    Gao, R. S.; Hall, S. R.; Swartz, W. H.; Spackman, J. R.; Watts, L. A.; Fahey, D. W.; Aikin, K. C.; Shetter, R. E.; Bui, T. P.

    2008-01-01

    Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.

  7. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

    Directory of Open Access Journals (Sweden)

    N. Cai

    2012-01-01

    Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

  8. Specific heat flow rate: an on-line monitor and potential control variable of specific metabolic rate in animal cell culture that combines microcalorimetry with dielectric spectroscopy.

    Science.gov (United States)

    Guan, Y; Evans, P M; Kemp, R B

    1998-06-05

    One of the requirements for enhanced productivity by the animal culture systems used in biotechnology is the direct assessment of the metabolic rate by on-line biosensors. Based on the fact that cell growth is associated with an enthalpy change, it is shown that the specific heat flow rate is stoichiometrically related to the net specific rates of substrates, products, and indeed to specific growth rate, and therefore a direct reflection of metabolic rate. Heat flow rate measured by conduction calorimetry has a technical advantage over estimates for many material flows which require assays at a minimum of two discrete times to give the rate. In order to make heat flow rate specific to the amount of the living cellular system, it would be advantageous to divide it by viable biomass. This requirement has been fulfilled by combining a continuous flow microcalorimeter ex situ with a dielectric spectroscope in situ, the latter measuring the viable cell mass volume fraction. The quality of the resulting biosensor for specific heat flow rate was illustrated using batch cultures of Chinese hamster ovary cells (CHO 320) producing recombinant human interferon-gamma (IFN-gamma) during growth in a stirred tank bioreactor under fully aerobic conditions. The measuring scatter of the probe was decreased significantly by applying the moving average technique to the two participant signals. It was demonstrated that the total metabolic rate of the cells, as indicated by the specific heat flow rate sensor, decreased with increasing time in batch culture, coincident with the decline in the two major substrates, glucose and glutamine, and the accumulation of the by-products, ammonia and lactate. Furthermore, the specific heat flow rate was an earlier indicator of substrate depletion than the flow rate alone. The calorimetric-respirometric ratio showed the intensive participation of anaerobic processes during growth and the related IFN-gamma production. Specific heat flow rate was

  9. Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

    Directory of Open Access Journals (Sweden)

    Hongbo Y.

    2015-06-01

    Full Text Available The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

  10. Effect of heating rate on toxicity of pyrolysis gases from some elastomers

    Science.gov (United States)

    Hilado, C. J.; Kosola, K. L.; Solis, A. N.

    1977-01-01

    The effect of heating rate on the toxicity of the pyrolysis gases from six elastomers was investigated, using a screening test method. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acrylonitrile rubber exhibited the greatest toxicity under these test conditions, and carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

  11. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Balša Terzić

    2014-10-01

    Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

  12. Effect of heating rate on toxicity of pyrolysis gases from some synthetic polymers

    Science.gov (United States)

    Hilado, C. J.; Soriano, J. A.; Kosola, K. L.

    1977-01-01

    The effect of heating rate on the toxicity of the pyrolysis gases from some synthetic polymers was investigate, using a screening test method. The synthetic polymers were polyethylene, polystyrene, polymethyl methacrylate, polycarbonate, ABS, polyaryl sulfone, polyether sulfone, and polyphenylene sulfide. The toxicants from the sulfur-containing polymers appeared to act more rapidly than the toxicants from the other polymers. It is not known whether this effect is due primarily to differences in concentration or in the nature of the toxicants. The carbon monoxide concentrations found do not account for the observed results.

  13. The influence of heating rate on superconducting characteristics of MgB2 obtained by spark plasma sintering technique

    Science.gov (United States)

    Aldica, G.; Burdusel, M.; Popa, S.; Enculescu, M.; Pasuk, I.; Badica, P.

    2015-12-01

    Superconducting bulks of MgB2 were obtained by the Spark Plasma Sintering (SPS) technique. Different heating rates of 20, 100, 235, 355, and 475 °C/min were used. Samples have high density, above 95%. The onset critical temperature Tc, is about 38.8 K. There is an optimum heating rate of ∼100 °C/min to maximize the critical current density Jc0, the irreversibility field Hirr, the product (Jc0 x μ0Hirr), and to partially avoid formation of undesirable flux jumps at low temperatures. Significant microstructure differences were revealed for samples processed with low and high heating rates in respect to grain boundaries.

  14. Playing the role: Power of love and love of power in Shakespeare's Twelfth Night

    Directory of Open Access Journals (Sweden)

    Ljubica Matek

    2014-12-01

    Full Text Available The author uses a methodological approach similar to one of New Historicism to give a new reading of Shakespeare’s comedy Twelfth Night, or What You Will. The play represents both a literary and a historical document which repeats the pattern of appropriating and exercising power used by Queen Elizabeth I. This reading reveals a new interpretative layer of Shakespeare’s seemingly apolitical comedy about mistaken identity and unrequited love which is resolved in a likewise seemingly typical happy ending that includes three marriages. A parallel analysis of text and context will show that Twelfth Night is a socially subversive text which points to the conclusion that masking seems to be a necessary prerequisite for achieving personal and political goals, both in the fictional context of the play and in the historical context of Elizabethan England.

  15. Introduction and session summaries for the proceedings of the twelfth symposium on biotechnology fuels and chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, E. (Oak Ridge National Lab., TN (USA)); Wyman, C.E. (Solar Energy Research Inst., Golden, CO (USA))

    1990-01-01

    This Twelfth Symposium on Biotechnology for Fuels and Chemicals continues to provide an annual forum for researchers from industry, universities, and government laboratories to exchange information on recent developments in emerging bioprocessing technologies. As in the past, innovative processing concepts are stressed that are in the early stages of development. The meeting began with a session on Thermal, Chemical, and Biological Processing, followed by two sessions on Applied Biological Research. Next, topics in Bioengineering Research were presented, and a special session on Biotechnology, Bioengineering, and the Solution of Environmental Problems concluded the Twelfth Symposium. Both presentations and posters provided information exchange among meeting participants, and several discussion groups were organized to consider special topics of interest to the meeting participants. This paper presents a brief description of the discussions.

  16. Thermal conductance and basal metabolic rate are part of a coordinated system for heat transfer regulation.

    Science.gov (United States)

    Naya, Daniel E; Spangenberg, Lucía; Naya, Hugo; Bozinovic, Francisco

    2013-09-22

    Thermal conductance measures the ease with which heat leaves or enters an organism's body. Although the analysis of this physiological variable in relation to climatic and ecological factors can be traced to studies by Scholander and colleagues, only small advances have occurred ever since. Here, we analyse the relationship between minimal thermal conductance estimated during summer (Cmin) and several ecological, climatic and geographical factors for 127 rodent species, in order to identify the exogenous factors that have potentially affected the evolution of thermal conductance. In addition, we evaluate whether there is compensation between Cmin and basal metabolic rate (BMR)-in such a way that a scale-invariant ratio between both variables is equal to one-as could be expected from the Scholander-Irving model of heat transfer. Our major findings are (i) annual mean temperature is the best single predictor of mass-independent Cmin. (ii) After controlling for the effect of body mass, there is a strong positive correlation between log10 (Cmin) and log10 (BMR). Further, the slope of this correlation is close to one, indicating an almost perfect compensation between both physiological variables. (iii) Structural equation modelling indicated that Cmin values are adjusted to BMR values and not the other way around. Thus, our results strongly suggest that BMR and thermal conductance integrate a coordinated system for heat regulation in endothermic animals and that summer conductance values are adjusted (in an evolutionary sense) to track changes in BMRs.

  17. Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate

    Science.gov (United States)

    Roberts, Dustyn; Hillstrom, Howard; Kim, Joo H.

    2016-01-01

    A subject-specific model of instantaneous cost of transport (ICOT) is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters—mass, height, (estimated) maximum oxygen uptake, and (estimated) maximum joint torques—are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90) inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326–0.348) of the experimental total COT (0.311–0.358) across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed) and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic) energy pathway similar to that of steady-state walking. PMID:28030598

  18. A simple parameterization of ozone infrared absorption for atmospheric heating rate calculations

    Science.gov (United States)

    Rosenfield, Joan E.

    1991-01-01

    A simple parameterization of ozone absorption in the 9.6-micron region which is suitable for two- and three-dimensional stratospheric and tropospheric models is presented. The band is divided into two parts, a brand center region and a band wing region, grouping together regions for which the temperature dependence of absorption is similar. Each of the two regions is modeled with a function having the form of the Goody random model, with pressure and temperature dependent band parameters chosen by empirically fitting line-by-line equivalent widths for pressures between 0.25 and 1000 mbar and ozone absorber amounts between 1.0 x 10 to the -7th and 1.0 cm atm. The model has been applied to calculations of atmospheric heating rates using an absorber amount weighted mean pressure and temperature along the inhomogeneous paths necessary for flux computations. In the stratosphere, maximum errors in the heating rates relative to line-by-line calculations are 0.1 K/d, or 5 percent of the peak cooling at the stratopause. In the troposphere the errors are at most 0.005 K/d.

  19. Effect of heating rate on temperature of titanium alloy (. cap alpha. +. beta. ). -->. beta. transformaton

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Markovskij, P.E. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki)

    1985-01-01

    The effect of doping of two-phase titaniums alloys and morphology of initial structure on the Tsub(t) temperature shift value of (..cap alpha..+..beta..)..--> beta.. transformation depending on heating rate is investigated. It has been found that the Tsub(t) shift occurs in the strictly determined temperature range depending on chemical alloy composition. The Tsub(t) shift is directly proportional to the Ksub(..beta..) coefficient applied as a quantitative alloying characteristic as well as a dimensional factor equal either to the plate thickness or the ..cap alpha..-phase globule diameter depending on the type of initial structure. In the limits of this temperature range the (..cap alpha..+..beta..)..--> beta..-transformation occurs completely according to the diffusion mechanism. The critical heating rate at which maximum permissible Tsub(t) value is attained and above which its stabilization is observed is determined by the same parameters - the alloy doping degree characterized by the Ksub(..beta..) coefficient and the ..cap alpha..-phase crystal dimensions in the initial structure.

  20. Mathematical model of cycad cones' thermogenic temperature responses: inverse calorimetry to estimate metabolic heating rates.

    Science.gov (United States)

    Roemer, R B; Booth, D; Bhavsar, A A; Walter, G H; Terry, L I

    2012-12-21

    A mathematical model based on conservation of energy has been developed and used to simulate the temperature responses of cones of the Australian cycads Macrozamia lucida and Macrozamia. macleayi during their daily thermogenic cycle. These cones generate diel midday thermogenic temperature increases as large as 12 °C above ambient during their approximately two week pollination period. The cone temperature response model is shown to accurately predict the cones' temperatures over multiple days as based on simulations of experimental results from 28 thermogenic events from 3 different cones, each simulated for either 9 or 10 sequential days. The verified model is then used as the foundation of a new, parameter estimation based technique (termed inverse calorimetry) that estimates the cones' daily metabolic heating rates from temperature measurements alone. The inverse calorimetry technique's predictions of the major features of the cones' thermogenic metabolism compare favorably with the estimates from conventional respirometry (indirect calorimetry). Because the new technique uses only temperature measurements, and does not require measurements of oxygen consumption, it provides a simple, inexpensive and portable complement to conventional respirometry for estimating metabolic heating rates. It thus provides an additional tool to facilitate field and laboratory investigations of the bio-physics of thermogenic plants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Heat rate improvement at Sunflower Electric`s Holcomb Station - a programmatic approach

    Energy Technology Data Exchange (ETDEWEB)

    Linville, C.; Nelson, K.E.; DesJardins, R.R.

    1996-05-01

    This paper describes the heat rate improvement program implemented at Sunflower Electric Power Corporations Holcomb Generating Station located in Holcomb, Kansas. The Holcomb Station is a large coal-fired generating plant that supplies electricity to Southwestern. Kansas and surrounding states. In 1993, Sunflower Electric (SEPC) established a continuing heat rate improvement program at the Holcomb Station which consisted of a periodic performance test program in combination with continuous on-line monitoring. This paper provides an overview of the test program and initial results and describes a unique approach to monitoring boiler feed pump performance especially suitable for on-line monitoring. implementation of a 15-user LAN-based on-line performance monitoring system is also described. In addition to technical issues, the paper addresses some of the {open_quotes}human factors{close_quotes} encountered while promoting acceptance and use of the on-line monitoring system by all levels of plant personnel. The importance of proper program planning and long term management support is stressed.

  2. Experimental investigation on heat transfer rate of Co–Mn ferrofluids in external magnetic field

    Directory of Open Access Journals (Sweden)

    Margabandhu M.

    2016-06-01

    Full Text Available Manganese substituted cobalt ferrite (Co1–xMnxFe2O4 with x = 0, 0.3, 0.5, 0.7 and 1 nanopowders were synthesized by chemical coprecipitation method. The synthesized magnetic nanoparticles were investigated by various characterization techniques, such as X-ray diffraction (XRD, vibrating sample magnetometry (VSM, scanning electron microscopy (SEM and thermogravimetric and differential thermal analysis (TG/DTA. The XRD results confirmed the presence of cubic spinel structure of the prepared powders and the average crystallite size of magnetic particles ranging from 23 to 45 nm. The VSM results showed that the magnetic properties varied with an increase in substituted manganese while SEM analysis showed the change in the morphology of obtained magnetic nanoparticles. The TG/DTA analysis indicated the formation of crystalline structure of the synthesized samples. The heat transfer rate was measured in specially prepared magnetic nanofluids (nanoparticles dispersed in carrier fluid transformer oil as a function of time and temperature in presence of external magnetic fields. The experimental analysis indicated enhanced heat transfer rate of the magnetic nanofluids which depended upon the strength of external magnetic field and chemical composition.

  3. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    Energy Technology Data Exchange (ETDEWEB)

    Bauk, Sabar, E-mail: sabar@usm.my [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hussin, Siti Fatimah [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Alam, Md. Shah [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Physics Department, Shahjalal University of Science and Technology, Sylhet (Bangladesh)

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  4. Investigations on the heat transport capability of a cryogenic oscillating heat pipe and its application in achieving ultra-fast cooling rates for cell vitrification cryopreservation.

    Science.gov (United States)

    Han, Xu; Ma, Hongbin; Jiao, Anjun; Critser, John K

    2008-06-01

    Theoretically, direct vitrification of cell suspensions with relatively low concentrations ( approximately 1 M) of permeating cryoprotective agents (CPA) is suitable for cryopreservation of almost all cell types and can be accomplished by ultra-fast cooling rates that are on the order of 10(6-7) K/min. However, the methods and devices currently available for cell cryopreservation cannot achieve such high cooling rates. In this study, we constructed a novel cryogenic oscillating heat pipe (COHP) using liquid nitrogen as its working fluid and investigated its heat transport capability to assess its application for achieving ultra-fast cooling rates for cell cryopreservation. The experimental results showed that the apparent heat transfer coefficient of the COHP can reach 2 x 10(5) W/m(2).K, which is two orders of the magnitude higher than traditional heat pipes. Theoretical analyzes showed that the average local heat transfer coefficient in the thin film evaporation region of the COHP can reach 1.2 x 10(6) W/m(2).K, which is approximately 10(3) times higher than that achievable with standard pool-boiling approaches. Based on these results, a novel device design applying the COHP and microfabrication techniques is proposed and its efficiency for cell vitrification is demonstrated through numerical simulation. The estimated average cooling rates achieved through this approach is 10(6-7)K/min, which is much faster than the currently available methods and sufficient for achieving vitrification with relatively low concentrations of CPA.

  5. The Dependence of Atmospheric Circulation and Heat Transport on the Planetary Rotation Rate

    Science.gov (United States)

    Basu, S.; Richardson, M. I.; Wilson, R. J.

    2002-12-01

    Simplified models of planetary climate require a parameterization for the equator-to-pole transport of heat and its dependence on factors, including the planetary rotation rate. Various such parameterizations exist, including ones based on the theory of baroclinic eddy mixing, and on principles of global entropy generation. However, such parameterizations are difficult to test given the limited available observational opportunities. In this study, we use a numerical model to examine heat flux dependencies, as part of a wider study of circulation regime sensitivity to rotation rates and other parameters. This study makes use of a simplified version of the Geophysical Fluid Dynamics Laboratory (GFDL) "Skyhi" General Circulation Model (GCM). All terrestrial hydrological processes have been stripped from the model, which in the form used here, is adapted from the Martian version of Skyhi. The atmosphere has the gas properties of CO2, except that it has been made uncondensible. No aerosols or surface ices are allowed. The model surface is flat, and of uniform albedo and thermal inertia. For the simulations presented in this study, the diurnal, seasonal, and eccentricity cycles have been disabled ({ i.e.} the surface and atmosphere receives constant, daily- and seasonally-averaged incident solar radiation). Radiative heating is treated with a band model for CO2 gas in the thermal and near-infrared bands. The use of a complex model to examine simplified theory of heat transport requires some justification since it is not necessarily clear that these models (GCM's) provide an accurate emulation of the real atmosphere (of any given planet). In this study, we have intentionally removed those aspects of GCM's that are of greatest concern. Especially for terrestrial GCM's, the hydrologic cycle is a major source of uncertainty due to radiative feedbacks, and cloud coupling to small-scale, convective mixing. For other planets, aerosols are important as radiatively and dynamical

  6. The effect of temperature and heating rate on char properties obtained from solar pyrolysis of beech wood.

    Science.gov (United States)

    Zeng, Kuo; Minh, Doan Pham; Gauthier, Daniel; Weiss-Hortala, Elsa; Nzihou, Ange; Flamant, Gilles

    2015-04-01

    Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000°C, with heating rates from 5 to 450°C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50°C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200°C then reduced significantly at 2000°C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450°C/s when final temperature was no lower than 1200°C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate.

  7. Effect of Heating Rate on Accelerated Carbide Spheroidisation (ASR in 100CrMnSi6-4 Bearing Steel

    Directory of Open Access Journals (Sweden)

    Hauserova D.

    2014-10-01

    Full Text Available Typical processing routes for bearing steels include a soft annealing stage, the purpose of which is to obtain a microstructure containing globular carbides in ferritic matrix. A newly developed process called ASR cuts the carbide spheroidisation times several fold, producing considerably finer globular carbides than conventional soft annealing. The present paper explores the effect of the heating rate and temperature on the accelerated carbide spheroidisation process and on the resulting hardness. Accelerated spheroidisation was achieved by thermal cycling for several minutes around various temperatures close to the transformation temperature at various heating rates applied by induction heating.

  8. Investigating Cooling Rates of a Controlled Lava Flow using Infrared Imaging and Three Heat Diffusion Models

    Science.gov (United States)

    Tarlow, S.; Lev, E.; Zappa, C. J.; Karson, J.; Wysocki, B.

    2011-12-01

    Observation and investigation of surface cooling rates of active lava flows can help constrain thermal parameters necessary for creating of more precise lava flow models. To understand how the lava cools, temperature data was collected using an infrared video camera. We explored three models of the release of heat from lava stream; one based on heat conduction, another based on crust thickness and radiation, and a third model based on radiative cooling and variable crust thickness. The lava flow, part of the Syracuse University Lava Project (http://lavaproject.syr.edu), was made by pouring molten basalt at 1300 Celsius from a furnace into a narrow trench of sand. Hanging roughly 2 m over the trench, the infrared camera, records the lava's surface temperature for the duration of the flow. We determine the average surface temperature of the lava flow at a fixed location downstream as the mean of the lateral cross section of each frame of the IR imagery. From the recorded IR frames, we calculate the mean cross-channel temperature for each downstream distance. We then examine how this mean temperature evolves over time, and plot cooling curves for selected down-stream positions. We then compared the observed cooling behavior to that predicted by three cooling models: a conductive cooling model, a radiative cooling model with constant crust thickness, and a radiative cooling model with variable crust thickness. All three models are solutions to the one-dimensional heat equation. To create the best fit for the conductive model, we constrained thermal diffusivity and to create the best fit for the radiative model, we constrained crust thickness. From the comparison of our data to the models we can conclude that the lava flow's cooling is primarily driven by radiation.

  9. Gamma ray heating rates due to chromium isotopes in stellar core during late stages of high mass stars (>10M⊙

    Directory of Open Access Journals (Sweden)

    Nabi Jameel-Un

    2017-01-01

    Full Text Available Gamma ray heating rates are thought to play a crucial role during the pre-supernova stage of high mass stars. Gamma ray heating rates, due to β±-decay and electron (positron capture on chromium isotopes, are calculated using proton-neutron quasiparticle random phase approximation theory. The electron capture significantly affects the lepton fraction (Ye and accelerates the core contraction. The gamma rays emitted as a result of weak processes heat the core and tend to hinder the cooling and contraction due to electron capture and neutrino emission. The emitted gamma rays tend to produce enormous entropy and set the convection to play its role at this stage. The gamma heating rates, on 50-60Cr, are calculated for the density range 10 < ρ (g.cm-3 < 1011 and temperature range 107 < T (K < 3.0×1010.

  10. Integration and software for thermal test of heat rate sensors. [space shuttle external tank

    Science.gov (United States)

    Wojciechowski, C. J.; Shrider, K. R.

    1982-01-01

    A minicomputer controlled radiant test facility is described which was developed and calibrated in an effort to verify analytical thermal models of instrumentation islands installed aboard the space shuttle external tank to measure thermal flight parameters during ascent. Software was provided for the facility as well as for development tests on the SRB actuator tail stock. Additional testing was conducted with the test facility to determine the temperature and heat flux rate and loads required to effect a change of color in the ET tank external paint. This requirement resulted from the review of photographs taken of the ET at separation from the orbiter which showed that 75% of the external tank paint coating had not changed color from its original white color. The paint on the remaining 25% of the tank was either brown or black, indicating that it had degraded due to heating or that the spray on form insulation had receded in these areas. The operational capability of the facility as well as the various tests which were conducted and their results are discussed.

  11. Development of a water boil-off spent-fuel calorimeter system. [To measure decay heat generation rate

    Energy Technology Data Exchange (ETDEWEB)

    Creer, J.M.; Shupe, J.W. Jr.

    1981-05-01

    A calorimeter system was developed to measure decay heat generation rates of unmodified spent fuel assemblies from commercial nuclear reactors. The system was designed, fabricated, and successfully tested using the following specifications: capacity of one BWR or PWR spent fuel assembly; decay heat generation range 0.1 to 2.5 kW; measurement time of < 12 h; and an accuracy of +-10% or better. The system was acceptance tested using a dc reference heater to simulate spent fuel assembly heat generation rates. Results of these tests indicated that the system could be used to measure heat generation rates between 0.5 and 2.5 kW within +- 5%. Measurements of heat generation rates of approx. 0.1 kW were obtained within +- 15%. The calorimeter system has the potential to permit measurements of heat generation rates of spent fuel assemblies and other devices in the 12- to 14-kW range. Results of calorimetry of a Turkey Point spent fuel assembly indicated that the assembly was generating approx. 1.55 kW.

  12. Diabatic heating rate estimates from European Centre for Medium-Range Weather Forecasts analyses

    Science.gov (United States)

    Christy, John R.

    1991-01-01

    Vertically integrated diabatic heating rate estimates (H) calculated from 32 months of European Center for Medium-Range Weather Forecasts daily analyses (May 1985-December 1987) are determined as residuals of the thermodynamic equation in pressure coordinates. Values for global, hemispheric, zonal, and grid point H are given as they vary over the time period examined. The distribution of H is compared with previous results and with outgoing longwave radiation (OLR) measurements. The most significant negative correlations between H and OLR occur for (1) tropical and Northern-Hemisphere mid-latitude oceanic areas and (2) zonal and hemispheric mean values for periods less than 90 days. Largest positive correlations are seen in periods greater than 90 days for the Northern Hemispheric mean and continental areas of North Africa, North America, northern Asia, and Antarctica. The physical basis for these relationships is discussed. An interyear comparison between 1986 and 1987 reveals the ENSO signal.

  13. Strengthened PAN-based carbon fibers obtained by slow heating rate carbonization.

    Science.gov (United States)

    Kim, Min-A; Jang, Dawon; Tejima, Syogo; Cruz-Silva, Rodolfo; Joh, Han-Ik; Kim, Hwan Chul; Lee, Sungho; Endo, Morinobu

    2016-03-23

    Large efforts have been made over the last 40 years to increase the mechanical strength of polyacrylonitrile (PAN)-based carbon fibers (CFs) using a variety of chemical or physical protocols. In this paper, we report a new method to increase CFs mechanical strength using a slow heating rate during the carbonization process. This new approach increases both the carbon sp(3) bonding and the number of nitrogen atoms with quaternary bonding in the hexagonal carbon network. Theoretical calculations support a crosslinking model promoted by the interstitial carbon atoms located in the graphitic interlayer spaces. The improvement in mechanical performance by a controlled crosslinking between the carbon hexagonal layers of the PAN based CFs is a new concept that can contribute further in the tailoring of CFs performance based on the understanding of their microstructure down to the atomic scale.

  14. Dependence of the width of the glass transition interval on cooling and heating rates

    Science.gov (United States)

    Schmelzer, Jürn W. P.; Tropin, Timur V.

    2013-01-01

    In a preceding paper [J. W. P. Schmelzer, J. Chem. Phys. 136, 074512 (2012), 10.1063/1.3685510], a general kinetic criterion of glass formation has been advanced allowing one to determine theoretically the dependence of the glass transition temperature on cooling and heating rates (or similarly on the rate of change of any appropriate control parameter determining the transition of a stable or metastable equilibrium system into a frozen-in, non-equilibrium state of the system, a glass). In the present paper, this criterion is employed in order to develop analytical expressions for the dependence of the upper and lower boundaries and of the width of the glass transition interval on the rate of change of the external control parameters. It is shown, in addition, that the width of the glass transition range is strongly correlated with the entropy production at the glass transition temperature. The analytical results are supplemented by numerical computations. Analytical results and numerical computations as well as existing experimental data are shown to be in good agreement.

  15. Resting metabolic rate and heat increment of feeding in juvenile South American fur seals (Arctocephalus australis).

    Science.gov (United States)

    Dassis, M; Rodríguez, D H; Ieno, E N; Denuncio, P E; Loureiro, J; Davis, R W

    2014-02-01

    Bio-energetic models used to characterize an animal's energy budget require the accurate estimate of different variables such as the resting metabolic rate (RMR) and the heat increment of feeding (HIF). In this study, we estimated the in air RMR of wild juvenile South American fur seals (SAFS; Arctocephalus australis) temporarily held in captivity by measuring oxygen consumption while at rest in a postabsorptive condition. HIF, which is an increase in metabolic rate associated with digestion, assimilation and nutrient interconversion, was estimated as the difference in resting metabolic rate between the postabsorptive condition and the first 3.5h postprandial. As data were hierarchically structured, linear mixed effect models were used to compare RMR measures under both physiological conditions. Results indicated a significant increase (61%) for the postprandial RMR compared to the postabsorptive condition, estimated at 17.93±1.84 and 11.15±1.91mL O2 min(-1)kg(-1), respectively. These values constitute the first estimation of RMR and HIF in this species, and should be considered in the energy budgets for juvenile SAFS foraging at-sea.

  16. A study on alkaline heat treated Mg-Ca alloy for the control of the biocorrosion rate.

    Science.gov (United States)

    Gu, X N; Zheng, W; Cheng, Y; Zheng, Y F

    2009-09-01

    To reduce the biocorrosion rate by surface modification, Mg-Ca alloy (1.4wt.% Ca content) was soaked in three alkaline solutions (Na(2)HPO(4), Na(2)CO(3) and NaHCO(3)) for 24h, respectively, and subsequently heat treated at 773K for 12h. Scanning electron microscopy and energy-dispersive spectroscopy results revealed that magnesium oxide layers with the thickness of about 13, 9 and 26microm were formed on the surfaces of Mg-Ca alloy after the above different alkaline heat treatments. Atomic force microscopy showed that the surfaces of Mg-Ca alloy samples became rough after three alkaline heat treatments. The in vitro corrosion tests in simulated body fluid indicated that the corrosion rates of Mg-Ca alloy were effectively decreased after alkaline heat treatments, with the following sequence: NaHCO(3) heatedheatedheated. The cytotoxicity evaluation revealed that none of the alkaline heat treated Mg-Ca alloy samples induced toxicity to L-929 cells during 7days culture.

  17. Investigations on the heat transport capability of a cryogenic oscillating heat pipe and its application in achieving ultra-fast cooling rates for cell vitrification cryopreservation☆

    OpenAIRE

    Han, Xu; Ma, Hongbin; Jiao, Anjun; Critser, John K.

    2008-01-01

    Theoretically, direct vitrification of cell suspensions with relatively low concentrations (~1 M) of permeating cryoprotective agents (CPA) is suitable for cryopreservation of almost all cell types and can be accomplished by ultra-fast cooling rates that are on the order of 106–7 K/min. However, the methods and devices currently available for cell cryopreservation cannot achieve such high cooling rates. In this study, we constructed a novel cryogenic oscillating heat pipe (COHP) using liquid ...

  18. Tick resistance and heat tolerance characteristics in cattle. III. Sweating rate

    Directory of Open Access Journals (Sweden)

    Cecília José Veríssimo

    2012-12-01

    Full Text Available Cattle in a sustainable tropical livestock should be heat tolerant and resistant to ticks. The relationship between Rhipicephalus (Boophilus microplus infestation and sweating rate, an important heat tolerance characteristic, was studied in six Nellore and four Holstein steers of seven-month-old. They were artificial infested (a.i. with 10,000 (Holstein and 20,000 (Nellore larvae in 16/Apr/2011. In days 20, 23 and 24 after the infestation, the 10 bigger females ticks found in whole animal were weighed and put in a chamber (27 oC and 80% RH, weighing the egg mass of each female tick fourteen days after. The sweating rate (SRskin, measured by Scheleger and Turner, 1963, method, in a shaved area of shoulder skin was evaluated in 14/Apr (2 days before the a.i. and in 05/May (19 days after a.i.. In 14/Apr the Scheleger and Turner, 1963, method was done on the coat not shaved (SRcoat. The sweating rate was measured in the afternoon (from 2 P.M., after 30 minutes of direct sunlight, on April. On May, the animals remained 60 minutes in direct sunlight because this day was colder. The experimental design was a non-probability sample restricted to the 10 available animals. Data from the steers’ sweating rate were analyzed using the General linear models of the SPSS® statistical package (version 12.0 using SRskin as dependent variable and breed and sampling date as independent variables. For SRcoat breed was the independent variable. Nellore, a tropical cattle breed, had higher SRskin (1,000.82 ± 64.59 g m-2 h-1, P< 0.001 than Holstein (620.45 ± 79.10 g m-2 h-1. SRskin was higher on May (1,187.33 ± 71.49 g m-2 h-1, P< 0.001 than on April (433.93 ± 71.49 g m-2 h-1. The correlation between the two different measurements of SR was positive and significant (r= 0,545, P<0,01, Pearson correlation. But in SRcoat the breed effect disappeared because the Holstein SRcoat increased (Holstein: 884.95 ± 472.12 g m-2 h-1 and Nellore: 1,060.72 ± 318.21 g m-2 h-1

  19. The effect of heat exposure on cortisol and catecholamine excretion rates in workers in glass manufacturing unit.

    Science.gov (United States)

    Vangelova, K; Deyanov, Ch; Velkova, D; Ivanova, M; Stanchev, V

    2002-12-01

    The aim of the investigation was to study the effect of long term repeated heat exposure on the excretion rates of stress hormones of workers in glass manufacturing unit. Sixteen operators, exposed to heat, were studied during the hot period and compared to a control group of 16 subjects, working in the same manufacturing unit. Both groups had moderate work load. The microclimate components and the Wet Bulb Globe Temperature were used for defining the heat exposure. The excretion rates of cortisol, adrenaline and noradrenaline were followed during the early morning shifts on three hour intervals using RIA and fluoriphotometric methods. Heart rate was followed, too. The psychosocial factors were measured by the "My job" questionnaire. Highly significantly higher cortisol, noradrenaline and adrenaline values were measured in the heat exposed operators compared to the control group, while significant differences of the psychosocial factors between the two groups lacked. Even if the heart rate was in the safe limits, the found alterations in the stress system are considerable and indicate heat stress. The work in conditions of overheat is associated with considerable heat stress and the possible health implications need to be clarified.

  20. Short communication: Effects of dairy calf hutch elevation on heat reduction, carbon dioxide concentration, air circulation, and respiratory rates.

    Science.gov (United States)

    Moore, D A; Duprau, J L; Wenz, J R

    2012-07-01

    Heat stress affects dairy calf welfare and can result in morbidity, mortality, and lower weight gain. The purpose of this project was to evaluate the effects of elevating the back of plastic calf hutches on measures of ventilation and heat stress. A total of 15 calves housed in individual hutches were enrolled, with each calf hutch serving as its own control. Heat, humidity, carbon dioxide, and wind speed were measured inside each hutch and the observations were compared with external measurements over two 24-h periods; 1 period without and 1 with hutch elevation. Respiratory rates were measured in the morning and afternoon as an indicator of the degree of heat stress experienced by calves with and without elevation of the hutch. When the hutch was elevated, internal hutch temperatures were cooler than external temperatures, hutch carbon dioxide levels were lower and respiratory rates were lower, particularly comparing the afternoon observation periods.

  1. Influence of radiant energy exchange on the determination of convective heat transfer rates to Orbiter leeside surfaces during entry

    Science.gov (United States)

    Throckmorton, D. A.

    1982-01-01

    Temperatures measured at the aerodynamic surface of the Orbiter's thermal protection system (TPS), and calorimeter measurements, are used to determine heating rates to the TPS surface during atmospheric entry. On the Orbiter leeside, where convective heating rates are low, it is possible that a significant portion of the total energy input may result from solar radiation, and for the wing, cross radiation from the hot (relatively) Orbiter fuselage. In order to account for the potential impact of these sources, values of solar- and cross-radiation heat transfer are computed, based upon vehicle trajectory and attitude information and measured surface temperatures. Leeside heat-transfer data from the STS-2 mission are presented, and the significance of solar radiation and fuselage-to-wing cross-radiation contributions to total energy input to Orbiter leeside surfaces is assessed.

  2. Apparatus for measuring the flow rate of a heat carrier and injection wells

    Energy Technology Data Exchange (ETDEWEB)

    Putilov, M.F.; Bar-Sliva, V.I.; Dichenko, M.A.; Nikiforov, Yu.V.; Petrov, A.I.; Turchaninov, Yu.N.

    1981-01-01

    A device is proposed for measuring the flow rate of the heat carrier in N wells, which contains a housing, turbine ( a permanent magnet is attached to the shaft eccentrically), a reed relay, a secondary converter and a power supply. In order to expand the measurement range by developing torque in the turbine it is equipped with additional reed relay, which is installed diametrically opposite the primary reed relay, and it also has a breaking unit made in the form of an additional permanent magnet placed on the turbine shaft. There was also a torodial core with a two-section winding and a winding power supply polarity switch in the frame. The primary and secondary reed relays are connected to the winding power supply polarity switch circuit. It in turn is connected to the secondary converter. In order to assure the possibility of changing the slope of the flow rate converter into a number of turbine revolutions it is equipped with a frequency to voltage converter with a setting mechanism. The frequency to voltage converter input is connected to the secondary converter, and the output is connected to the power supply source.

  3. The effect of heating rate and composition on the properties of spark plasma sintered zirconium diboride based composites

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, Alexandra; Bo Zhenyu [School of Materials Engineering, Purdue University, West Lafayette, IN 47907 (United States); Hodson, Stephen; Fisher, Timothy [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States); Stanciu, Lia, E-mail: lstanciu@purdue.edu [School of Materials Engineering, Purdue University, West Lafayette, IN 47907 (United States)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We investigated the effect of heating rate on spark plasma sintering of ZrB{sub 2}-SiC-ZrC composites. Black-Right-Pointing-Pointer Adding SiC up to 10 wt.% had a positive effect on densification and strength. Black-Right-Pointing-Pointer Increasing heating rate promoted densification and retarded grain growth when SiC and ZrC content was above 15 wt.%, respectively. Black-Right-Pointing-Pointer Increasing heating rate had a slight negative effect on densification when SiC and ZrC content was at 10%, respectively. - Abstract: Five different compositions of ZrB{sub 2}-SiC-ZrC were prepared and then processed by spark plasma sintering (SPS) to a maximum temperature of 2000 Degree-Sign C, with heating rates of 100 Degree-Sign C/min and 200 Degree-Sign C/min. Grain size, density, Rockwell hardness, flexural strength, and thermal conductivity were evaluated for the processed composites. Adding SiC up to 10 wt.% had a positive effect on densification and strength. Increasing the heating rate promoted densification and less overall grain growth for samples with SiC and ZrC above 15 wt.% each, and had a slight negative effect on densification when these values were at 10%.

  4. Twelfth symposium on biotechnology for fuels and chemicals: Program and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Scheitlin, F.M. (ed.)

    1990-01-01

    This report is the program and abstracts of the twelfth symposium on biotechnology for fuels and chemicals, held on May 7--11, 1990, at Gatlinburg, Tennessee. The symposium, sponsored by the Department of Energy, Oak Ridge National Laboratory, Solar Energy Research Institute, Badger Engineers, Inc., Gas Research Institute, and American Chemical Society, consists of five sessions: Session 1, thermal, chemical, and biological processing; Session 2 and 3, applied biological research; Session 4, bioengineering research; and Session 5, biotechnology, bioengineering, and the solution of environmental problems. It also consists of a poster session of the same five subject categories.

  5. Parametric analysis of air–water heat recovery concept applied to HVAC systems: Effect of mass flow rates

    Directory of Open Access Journals (Sweden)

    Mohamad Ramadan

    2015-09-01

    Full Text Available In the last three decades, the world has experienced enormous increases in energy and fuel consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. The present work concerns a coupling between energy recovery and Heating, Ventilating and Air Conditioning HVAC domains and aims to apply heat recovery concepts to HVAC applications working on refrigeration cycles. It particularly uses the waste energy of the condenser hot air to heat/preheat domestic water. The heat exchanger considered in the recovery system is concentric tube heat exchanger. A thermal modeling of the complete system as well as a corresponding iterative code are developed and presented. Calculations with the code are performed and give pertinent magnitude orders of energy saving and management in HVAC applications. A parametric analysis based on several water and air flow rates is carried out. It was shown that water can be heated from 25 to 70 °C depending on the mass flow rates and cooling loads of the HVAC system. The most efficient configurations are obtained by lowering the air flow rate of the condenser fan.

  6. Radiative energy balance of Venus: An approach to parameterize thermal cooling and solar heating rates

    Science.gov (United States)

    Haus, R.; Kappel, D.; Arnold, G.

    2017-03-01

    Thermal cooling rates QC and solar heating rates QH in the atmosphere of Venus at altitudes between 0 and 100 km are investigated using the radiative transfer and radiative balance simulation techniques described by Haus et al. (2015b, 2016). QC strongly responds to temperature profile and cloud parameter changes, while QH is less sensitive to these parameters. The latter mainly depends on solar insolation conditions and the unknown UV absorber distribution. A parameterization approach is developed that permits a fast and reliable calculation of temperature change rates Q for different atmospheric model parameters and that can be applied in General Circulation Models to investigate atmospheric dynamics. A separation of temperature, cloud parameter, and unknown UV absorber influences is performed. The temperature response parameterization relies on a specific altitude and latitude-dependent cloud model. It is based on an algorithm that characterizes Q responses to a broad range of temperature perturbations at each level of the atmosphere using the Venus International Reference Atmosphere (VIRA) as basis temperature model. The cloud response parameterization considers different temperature conditions and a range of individual cloud mode factors that additionally change cloud optical depths as determined by the initial latitude-dependent model. A QH response parameterization for abundance changes of the unknown UV absorber is also included. Deviations between accurate calculation and parameterization results are in the order of a few tenths of K/day at altitudes below 90 km. The parameterization approach is used to investigate atmospheric radiative equilibrium (RE) conditions. Polar mesospheric RE temperatures above the cloud top are up to 70 K lower and equatorial temperatures up to 10 K higher than observed values. This radiative forcing field is balanced by dynamical processes that maintain the observed thermal structure.

  7. Mixing state of aerosols over the Indo-Gangetic Plain: Radiative forcing and heating rate

    Science.gov (United States)

    Srivastava, R.; Ramachandran, S.

    2012-12-01

    ratio is calculated from the geometry of core-shell particles, which depends on the mass and density of the core and shell. The size distribution parameters and refractive indices of different aerosol species are taken from OPAC database [3]. Different fractions of black carbon, water soluble and mineral dust aerosols involved in core-shell mixing emerge as the most probable mixing states over the IGP. Aerosol forcing for external mixing shows higher deviations from those for probable mixing cases during winter and pre-monsoon. The heating rate over Kanpur and Gandhi College in the lower troposphere is similar during pre-monsoon (March-May) ( 0.75 K day^{-1}) and monsoon (June-September) ( 0.5 K day^{-1}), while differences occur in other seasons [4]. Aerosol heating rate profiles exhibit primary and secondary peaks over the IGP and exhibit seasonal variations. Details on the calculations of aerosol mixing states over IGP, the impact of aerosol mixing state on aerosol forcing and heating rate will be discussed. References: [1] Intergovernmental panel on climate change (2007), Solomon S. et al. (eds.), Cambridge Univ. Press, NewYork. [2] Holben B. N., et al. (2001), J. Geophys. Res., 106(D11), 12067-12097. [3] Hess M., P. Koepke, I. Schult (1998), Bull. Am. Meteorol. Soc., 79, 831-844. [4] Srivastava R., S. Ramachandran (2012), Q. J. R. Meteorol. Soc., 138, doi:10.1002/qj.1958.

  8. Heart rate variability and heat sensation during CT coronary angiography: Low-osmolar versus iso-osmolar contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Svensson, Anders; Ripsweden, Jonaz; Aspelin, Peter; Cederlund, Kerstin; Brismar, B. Torkel (Dept. of Clinical Science, Intervention and Technology, Karolinska Inst., Div. of Medical Imaging and Technology and Dept. of Radiology, Karolinska Univ. Hospital, Huddinge, Stockholm (Sweden)), e-mail: anders.svensson@karolinska.se; Rueck, Andreas (Div. of Cardiology, Dept. of Internal Medicine, Karolinska Inst., Karolinska Univ. Hospital, Stockholm (Sweden))

    2010-09-15

    Background: During computed tomography coronary angiography (CTCA) unexpected changes in heart rate while scanning may affect image quality. Purpose: To evaluate whether an iso-osmolar contrast medium (IOCM, iodixanol) and a low-osmolar contrast medium (LOCM, iomeprol) affect heart rate and experienced heat sensation differently. Material and Methods: One hundred patients scheduled for CTCA were randomized to receive either iodixanol 320 mgI/ml or iomeprol 400 mgI/ml. Depending on their heart rate, the patients were assigned to one of five scanning protocols, each optimized for different heart rate ranges. During scanning the time between each heart beat (hb) was recorded, and the corresponding heart rate was calculated. For each contrast medium (CM) the average heart rate, the variation in heart rate from individual mean heart rate, and the mean deviation from the predefined scanning protocol were calculated. Experience of heat was obtained immediately after scanning by using a visual analog scale (VAS). Examination quality was rated by two radiologists on a three-point scale. Results: The mean variation in heart rate after IOCM was 1.4 hb/min and after LOCM it was 4.4 hb/min (NS). The mean deviations in heart rate from that in the predefined scanning protocol were 2.0 hb/min and 4.7 hb/min, respectively (NS). A greater number of arrhythmic hb were observed after LOCM compared with IOCM (P<0.001). There was no statistically significant difference in image quality. The LOCM group reported a stronger heat sensation after CM injection than the IOCM group (VAS =36 mm and 18 mm, P<0.05). Conclusion: At clinically used concentrations the IOCM, iodixanol 320 mgI/ml, does not increase the heart rate during CTCA and causes less heart arrhythmia and less heat sensation than the LOCM, iomeprol 400 mgI/ml

  9. Twelfth grade follow-up of the effectiveness of a middle school-based substance abuse prevention program.

    Science.gov (United States)

    Shope, J T; Copeland, L A; Kamp, M E; Lang, S W

    1998-01-01

    A twelfth-grade follow-up afforded the opportunity to assess the long-term effects of substance abuse prevention delivered in sixth and seventh grades. A social pressures resistance skills curriculum implemented by classroom teachers had been evaluated with short-term positive results previously reported. Students completed self-administered questionnaires at sixth grade pre- and posttests, and at seventh and twelfth-grade posttests. Curriculum group students received lessons on alcohol, tobacco (cigarettes and smokeless), marijuana, and cocaine, which were later incorporated into the Michigan Model for Comprehensive School Health Education. This evaluation used data from 262 students who completed all four questionnaires and who received the complete two-year intervention or no intervention. Repeated measures analyses of variance demonstrated that significant effects evident at seventh grade for alcohol use and misuse, as well as cigarette, cocaine, and other drug use were generally not maintained through twelfth grade. Ongoing reinforcement of effective prevention is recommended.

  10. EXPERIMENTAL STUDY ON PREMIX COMBUSTION AT ISOSCELES TRIANGLE TYPE RATE OF HEAT RELEASE FOR SQUISH TYPE COMBUSTION CHAMBER

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper presents a theory on premix fuel combustion at nearisosceles triangle type rate of heat release,describes the measures taken for the combustion system,points out its many theoretical advantages,and that it can solve effectively the problems of rough running,fuel consumption and exhaust emission.Two squish lip type combustion chambers are designed to match separately with multiple holes injector and conical spray type injector in order to achieve premix combustion at near isosceles triangle type rate of heat release.Experimental studies on two single cylinder diesel engines showed that premix combustion at isosceles triangle type rate of heat release resulted in longer ignition delay period,larger amount of fuel injected into cylinder during the ignition delay period,lower maximum pressure,better fuel economy,and better exhaust emission.

  11. Average Heating Rate of Hot Atmospheres in Distant Clusters by Radio AGN: Evidence for Continuous AGN Heating

    CERN Document Server

    Ma, C -J; Nulsen, P E J; Schaffer, R; Vikhlinin, A

    2011-01-01

    X-ray observations of nearby clusters and galaxies have shown that energetic feedback from active galactic nuclei (AGN) is heating hot atmospheres and is probably the principal agent that is offsetting cooling flows. Here we examine AGN heating in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree X-ray Cluster survey with radio sources in the NRAO VLA Sky Survey. The jet power for each radio source was determined using scaling relations between radio power and cavity power determined for nearby clusters, groups, and galaxies with atmospheres containing X-ray cavities. Roughly 30% of the clusters show radio emission above a flux threshold of 3 mJy within the central 250 kpc that is presumably associated with the brightest cluster galaxy. We find no significant correlation between radio power, hence jet power, and the X-ray luminosities of clusters in redshift range 0.1 - 0.6. The detection frequency of radio AGN is inconsistent with the presence of strong cooling flows in...

  12. Influence of heat stress on arterial baroreflex control of heart rate in the baboon.

    Science.gov (United States)

    Gorman, A J; Proppe, D W

    1982-07-01

    The influence of environmental heat stress on the arterial baroreflex control of heart rate (HR) was studied in eight conscious, chronically instrumented baboons. Inflations of balloon occluders around the inferior vena cava (IVC) and thoracic descending aorta (DA) were used to produce acute, graded changes in mean arterial blood pressure (MABP) in 5 mm Hg intervals ranging from +/- 5 to +/- 25 mm Hg. After determination of the HR responses to changes in MABP in the normothermic baboon (blood temperature less than or equal to 37.6 degrees C), the animal was subjected to environmental heating to produce hyperthermia. When blood temperature reached approximately 39.5 degrees C, HR responses to graded DA and IVC occlusions were again determined. During hyperthermia, the HR sensitivity (delta HR/ delta MABP) to MABP changes was markedly diminished for reductions in MABP and significantly enhanced for increases in MABP. To determine whether these alterations in the HR response to changes in MABP were due to an alteration of the baroreflex control of HR, full, sigmoid-shaped HR-MABP curves for both the normothermic and hyperthermic states were constructed and characterized by total HR range, estimated slope of the steep portion of the curve, and MABP at the midpoint of the HR range (BP50). During hyperthermia (1) the whole HR-MABP curve shifted significantly upward by 35-40 beats/min, (2) total HR range, the estimated slope, and BP50 did not change, and (3) the control point (pre-occlusion HR-MABP value) curves were also constructed during either beta-adrenergic blockade or cholinergic (Ch)-receptor blockade in the normothermic and hyperthermic state. Similar to that seen for the unblocked heart, the whole HR-MABP curves were also shifted upward during hyperthermia in this group of baboons with no alteration in the total HR range, the estimated slope, or BP50. The upward shift in the HR-MABP curve during Ch-receptor blockade, unlike during beta-receptor blockade, was

  13. Qinghai Newly Adds 1 Million Tonnes of Copper and 2 Million Tonnes of Lead Zinc In the “Twelfth Five Year Plan” period

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The reporter recently learned from Qinghai Province Geological Prospecting Bureau that Qinghai’s geological prospecting for the"Twelfth Five Year Plan"period had made significant breakthroughs,and newly submitted58 orefields.It has been learned that,during the"Twelfth

  14. Increasing the rate of heating: a potential therapeutic approach for achieving synergistic tumour killing in combined hyperthermia and chemotherapy.

    Science.gov (United States)

    Tang, Yuan; McGoron, Anthony J

    2013-01-01

    A synergistic cancer cell killing effect of sub-lethal hyperthermia and chemotherapy has been reported extensively. In this study, in vitro cell culture experiments with a uterine cancer cell line (MES-SA) and its multidrug resistant (MDR) variant MES-SA/Dx5 were conducted in order to investigate the role of heating rate in achieving a synergistic effect. The mode of cell death, induction of thermal tolerance and P-glycoprotein (P-gp) mediated MDR following two different rates of heating were studied. Doxorubicin (DOX) was used as the chemotherapy drug. A rapid rate hyperthermia was achieved by near infrared laser (NIR) excited indocyanine green (ICG) dye (absorption maximum at 808 nm, ideal for tissue penetration). A slow rate hyperthermia was provided by a cell culture incubator. The potentiating effect of hyperthermia to chemotherapy can be maximised by increasing the rate of heating. When delivered at the same thermal dose, a rapid increase in temperature from 37°C to 43°C caused more cell membrane damage than gradually heating the cells from 37°C to 43°C and thus allowed for more intracellular accumulation of DOX. Meanwhile, the rapid rate laser-ICG hyperthermia at 43°C caused cell necrosis whereas the slow rate incubator hyperthermia at 43°C induced mild apoptosis. At 43°C a positive correlation between thermal tolerance and the length of hyperthermia exposure is identified. This study shows that by increasing the rate of heating, less thermal dose is needed in order to overcome P-gp mediated MDR.

  15. Can Reptile Embryos Influence Their Own Rates of Heating and Cooling?

    OpenAIRE

    Wei-Guo Du; Ming-Chung Tu; Radder, Rajkumar S.; Richard Shine

    2013-01-01

    Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars) cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. ...

  16. On the sensitivity of dimensional stability of high density polyethylene on heating rate

    Directory of Open Access Journals (Sweden)

    2007-02-01

    Full Text Available Although high density polyethylene (HDPE is one of the most widely used industrial polymers, its application compared to its potential has been limited because of its low dimensional stability particularly at high temperature. Dilatometry test is considered as a method for examining thermal dimensional stability (TDS of the material. In spite of the importance of simulation of TDS of HDPE during dilatometry test it has not been paid attention by other investigators. Thus the main goal of this research is concentrated on simulation of TDS of HDPE. Also it has been tried to validate the simulation results and practical experiments. For this purpose the standard dilatometry test was done on the HDPE speci­mens. Secant coefficient of linear thermal expansion was computed from the test. Then by considering boundary conditions and material properties, dilatometry test has been simulated at different heating rates and the thermal strain versus temper­ature was calculated. The results showed that the simulation results and practical experiments were very close together.

  17. Spatial statistical point prediction guidance for heating-rate-limited aeroassisted orbital transfer

    Science.gov (United States)

    Ghosh, Pradipto; Conway, Bruce A.

    2015-06-01

    Feedback control of constrained non-linear dynamical systems satisfying a certain optimality criterion and meeting a specified transfer objective in the state space is recognized as one of the most challenging problems in control theory. One approach to computing optimal feedback policies is the dynamic programming route of numerically solving the Hamilton-Jacobi-Bellman (HJB) partial differential equation directly. In this paper an alternate and more tractable dynamic programming approach, the optimal feedback synthesis method, is utilized. The effectiveness of this method is demonstrated through an explicit guidance scheme for the heating-rate-constrained maneuver of an Aeroassisted Transfer Vehicle (AOTV). In optimal feedback synthesis, a feedback chart is constructed from a family of open-loop extremals, thus ensuring optimality with respect to any initial condition in the family. This paper presents a solution to the AOTV optimal feedback synthesis problem using the Gaussian process spatial prediction method of universal kriging. A closed-form expression for a near-optimal guidance law is derived. Its performance is found to be very promising; initial atmospheric entry errors due to simulated thruster misfiring are seen to be accurately corrected while the algebraic state-inequality constraint is closely respected.

  18. The Roots of Fencing from the Twelfth to the Fourteenth Centuries in the French Language Area

    Directory of Open Access Journals (Sweden)

    Dupuis Olivier

    2015-05-01

    Full Text Available This article offers a partial overview on fencing, as recognized through archive records, as well as French epics and romances from the twelfth to the early fourteenth century. In the twelfth century, fencing was only attested through knightly vocabulary as a way to describe actions performed during single combats involving a combination of shield and another weapon, most commonly a sword. Fencing was progressively dissociated from the knightly arts and there were even few mentions of its use by common people. There are archive records from the thirteenth century of individuals bearing the nickname “fencer”, although there is rarely enough context to be certain that they were really practicing the art. At the end of the thirteenth century, archives and narrative fiction show an established fashion for a certain form of fencing with a short round shield, the buckler. This is clearly established in London where surviving manuscripts include many regulations on fencing, however the fashion was also spread in the continent, even though it seems to be less documented.

  19. Before Grosseteste: Roger of Hereford and calendar reform in eleventh- and twelfth-century England.

    Science.gov (United States)

    Moreton, J.

    1995-12-01

    The existence in the West Country - that area of England that is nearest to the Welsh border - in the eleventh and twelfth centuries of a group of scholars with scientific interests has long been recognized. The part that compotus played in the development of these interests was noted, but it has not been studied in any detail. It was here that a proposal for a reform of the ecclesiastical calendar, based not only on the reckoning traditionally attributed to Dionysius Exiguus but relating also to observed phenomena, was arrived at, then verified with the use of newly available scientific ideas from Arabic sources. One reason for the neglect of this topic is that three very important computistical treatises - the eleventh-century Compotus of Gerland and those of Roger of Hereford and the writer who has been identified with a certain "Constabularius", both from the twelfth century - have not been printed. The aim of this article is to explain why the study of compotus flourished in the West Country and then to examine its development in these and related treatises.

  20. Idiopathic Ninth, Tenth, and Twelfth Cranial Nerve Palsy with Ipsilateral Headache: A Case Report

    Directory of Open Access Journals (Sweden)

    Sun Seung-Ho

    2012-12-01

    Full Text Available Objective: This case report is to report the effect of Korean traditional treatment for idiopathic ninth, tenth, and twelfth cranial nerve palsy with ipsilateral headache. Methods: The medical history and imaging and laboratory test of a 39-year-old man with cranial palsy were tested to identify the cause of disease. A 0.2-mL dosage of Hwangyeonhaedoktang pharmacopuncture was administered at CV23 and CV17, respectively. Acupuncture was applied at P06, Li05, TE05, and G37 on the right side of the body. Zhuapiandutongbang (左偏頭痛方 was administered at 30 minutes to 1 hour after mealtime three times a day. The symptoms were investigated using Visual Analogue Scale (VAS. Results: The results of magnetic resonance imaging (MRI, computed tomography (CT, and laboratory tests were normal. The medical history showed no trauma, other illnesses, family history of diseases, medications, smoking, drinking and so on. All symptoms disappeared at the 10th day of treatment. Conclusion: Korean traditional treatment such as acupuncture, pharmcopuncture, and herbal medicine for the treatment of ninth, tenth, and twelfth cranial nerve palsy of unknown origin is suggested to be effective even though this conclusion is based on a single.

  1. Numerical studies on sizing/ rating of plate fin heat exchangers for a modified Claude cycle based helium liquefier/ refrigerator

    Science.gov (United States)

    Goyal, M.; Chakravarty, A.; Atrey, M. D.

    2017-02-01

    Performance of modern helium refrigeration/ liquefaction systems depends significantly on the effectiveness of heat exchangers. Generally, compact plate fin heat exchangers (PFHE) having very high effectiveness (>0.95) are used in such systems. Apart from basic fluid film resistances, various secondary parameters influence the sizing/ rating of these heat exchangers. In the present paper, sizing calculations are performed, using in-house developed numerical models/ codes, for a set of high effectiveness PFHE for a modified Claude cycle based helium liquefier/ refrigerator operating in the refrigeration mode without liquid nitrogen (LN2) pre-cooling. The combined effects of secondary parameters like axial heat conduction through the heat exchanger metal matrix, parasitic heat in-leak from surroundings and variation in the fluid/ metal properties are taken care of in the sizing calculation. Numerical studies are carried out to predict the off-design performance of the PFHEs in the refrigeration mode with LN2 pre-cooling. Iterative process cycle calculations are also carried out to obtain the inlet/ exit state points of the heat exchangers.

  2. Effects of heating method and conditions on the evaporation rate and quality attributes of black mulberry (Morus nigra) juice concentrate.

    Science.gov (United States)

    Fazaeli, Mahboubeh; Hojjatpanah, Ghazale; Emam-Djomeh, Zahra

    2013-02-01

    Black mulberry juice was concentrated by different heating methods, including conventional heating and microwave heating, at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method on evaporation rate, quality attributes of concentrated juice were investigated. The final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at 100, 38.5, and 7.3 kPa respectively by using a rotary evaporator. Applying microwave energy decreased required times to 115, 95, and 60 min. The changes in color, anthocyanin content during the concentration processes were investigated. Hunter parameters (L, a, and b) were measured to estimate the intensity of color loss. All Hunter color parameters decreased with time. Results showed that the degradation of color and consequently anthocyanins, was more pronounced in rotary evaporation compared to microwave heating method.

  3. Influence of product thickness, chamber pressure and heating conditions on production rate of freeze-dried yoghurt

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, N.K. [G.B. Pant Univ., of Agriculture and Technology (India). Dept. of Mechanical Engineering; Arora, C.P. [Indian Inst. of Tech., New Delhi (India)

    1995-06-01

    The effects of product thickness, chamber pressure and heating conditions on product temperature profiles and production rate of freeze-dried yoghurt were investigated experimentally. Three sample thicknesses - 3.8 mm, 6.2 mm and 9.4 mm - were tested at chamber pressures of 0.01 and 0.5 mmHg. The production rate increased by decreasing product thickness in contact heating through the bottom of the frozen layer, whereas no significant change was observed in radiant heating. A reduction in chamber pressure from 0.50 to 0.01 mmHg increased the drying time in radiant heating. Maximum production rate was obtained when the thickness of dried product was 6.2 mm, when heat was transferred simultaneously through the frozen and dried layers, and the chamber pressure was at 0.01 mmHg. Use of the product tray developed in this study prevents the growth of dry layers at the contact surfaces. (Author)

  4. Impact of heating rate and solvent on Ni-based catalysts prepared by solution combustion method for syngas methanation

    Directory of Open Access Journals (Sweden)

    Zeng Yan

    2014-12-01

    Full Text Available Ni-Al2O3 catalysts prepared by solution combustion method for syngas methanation were enhanced by employing various heating rate and different solvent. The catalytic properties were tested in syngas methanation. The result indicates that both of heating rate and solvent remarkably affect Ni particle size, which is a key factor to the catalytic activity of Ni-Al2O3 catalysts for syngas methanation. Moreover, the relationship between Ni particle size and the production rate of methane per unit mass was correlated. The optimal Ni-Al2O3 catalyst prepared in ethanol at 2°C/min, achieves a maximum production rate of methane at the mean size of 20.8 nm.

  5. The biophysical and physiological basis for mitigated elevations in heart rate with electric fan use in extreme heat and humidity

    Science.gov (United States)

    Ravanelli, Nicholas M.; Gagnon, Daniel; Hodder, Simon G.; Havenith, George; Jay, Ollie

    2017-02-01

    Electric fan use in extreme heat wave conditions has been thought to be disadvantageous because it might accelerate heat gain to the body via convection. However, it has been recently shown that fan use delays increases in heart rate even at high temperatures (42 °C) in young adults. We here assess the biophysical and physiological mechanisms underlying the apparently beneficial effects of fan use. Eight males (24 ± 3 y; 80.7 ± 11.7 kg; 2.0 ± 0.1 m2) rested at either 36 °C or 42 °C, with (F) or without (NF) electric fan use (4.2 m/s) for 120 min while humidity increased every 7.5 min by 0.3 kPa from a baseline value of 1.6 kPa. Heart rate (HR), local sweat rate (LSR), cutaneous vascular conductance (CVC), core and mean skin temperatures, and the combined convective/radiative heat loss (C+R), evaporative heat balance requirements (Ereq) and maximum evaporative potential (Emax) were assessed. C+R was greater with fan use at 36 °C (F 8 ± 6, NF 2 ± 2 W/m2; P = 0.04) and more negative (greater dry heat gain) with fan use at 42 °C (F -78 ± 4, NF -27 ± 2 W/m2; P prevented by fan use but not without a fan, LSR was higher in NF at both 36 °C ( P = 0.04) and 42 °C ( P = 0.05), and skin temperature was higher in NF at 42 °C ( P = 0.05), but no differences in CVC or core temperatures were observed (all P > 0.05). These results suggest that the delayed increase in heart rate with fan use during extreme heat and humidity is associated with improved evaporative efficiency.

  6. Effect of high heating rate on thermal decomposition behaviour of titanium hydride (TiH2) powder in air

    Indian Academy of Sciences (India)

    A Rasooli; M A Boutorabi; M Divandari; A Azarniya

    2013-04-01

    DTA and TGA curves of titanium hydride powder were determined in air at different heating rates. Also the thermal decomposition behaviour of the aforementioned powder at high heating rates was taken into consideration. A great breakthrough of the practical interest in the research was the depiction of the H2-time curves of TiH2 powder at various temperatures in air. In accordance with the results, an increase in heating rate to higher degrees does not change the process of releasing hydrogen from titanium hydride powder, while switching it from internal diffusion to chemical reaction. At temperatures lower than 600 °C, following the diffusion of hydrogen and oxygen atoms in titanium lattice, thin layers TiH phase and oxides form on the powder surface, controlling the process. On the contrary, from 700 °C later on, the process is controlled by oxidation of titanium hydride powder. In fact, the powder oxidation starts around 650 °C and may escalate following an increase in the heating rate too.

  7. Couette and Poiseuille flows in a low viscosity asthenosphere: Effects of internal heating rate, Rayleigh number, and plate representation

    Science.gov (United States)

    Shiels, C.; Butler, S. L.

    2015-09-01

    Mantle convection models with a low viscosity asthenosphere and high viscosity surface plates have been shown to produce very large aspect ratio convection cells like those inferred to exist in Earth's mantle and to exhibit two asthenospheric flow regimes. When the surface plate is highly mobile, the plate velocity exceeds the flow velocities in the asthenosphere and the plate drives a Couette-type flow in the asthenospheric channel. For sluggish plates, the flow velocities in the asthenosphere exceed the plate velocity and the asthenospheric flow is more Poiseuille-like. It has been shown that under certain circumstances, flows become increasingly Couette-like as the aspect ratio of the plate is increased in numerical simulations. These models also show an increase in the average surface heat flux with aspect ratio which is counterintuitive, as one would expect that large aspect ratio models would result in older and colder oceanic lithosphere. Previous investigations have used single internal heating rates and Rayleigh numbers and a plate formulation that did not preclude significant deformation within the plate. In this paper, we investigate the conditions necessary for Couette and Poiseuille asthenospheric flows and for surface heat flux to increase with plate aspect ratio by varying the internal heating rate, the Rayleigh number and the representation of surface plates in 2D mantle convection models Plates are represented as a high viscosity layer with (1) a free-slip top surface boundary condition and (2) a force-balance boundary condition that imposes a constant surface velocity within the plate. We find that for models with a free-slip surface boundary condition, the internal heating rate and Rayleigh number do not strongly affect the dominance of Couette or Poiseuille flows in the asthenosphere but the increase in surface heat flux with model aspect ratio in the Poiseuille asthenospheric flow regime increases with internal heating rate. For models using

  8. Aerosol Climatology at Pune, Western India: Implications to Direct Radiative Forcing and Heating Rates

    Science.gov (United States)

    Pandithurai, G.; Pinker, R. T.; Devara, P. C.; Raj, P. E.; Jayarao, Y.; Dani, K. K.; Maheskumar, R. S.; Sonbawne, S. M.; Saha, S. K.; Bhawar, R.; Shinde, U. P.

    2005-12-01

    Extensive aerosol observations were carried out at Indian Institute of Tropical Meteorology (IITM), Pune, an urban site in the western part of the country, using a Prede (Model POM-01L) sun/sky radiometer and a bi-static Argon ion lidar since December 2000 and October 1986, respectively. The sun/sky radiometer was operated daily at every 15 minute interval during day-time to derive column aerosol optical parameters such as aerosol optical depth (AOD), single scattering albedo (SSA), asymmetry parameter (ASY) while the lidar was operated weekly in the early-night period to derive vertical distributions of aerosol number density. The sun/sky radiance data collected during the above period have been analysed by using the radiative transfer model SkyRadPack version 3.0 (Nakajima et al. 1996) to retrieve AOD, SSA and ASY. AOD and SSA retrieved at 15-minutes interval were averaged to get monthly means. On every year from 2000 to 2005, monthly means of AOD show gradual increase of aerosol loading from December to April and Angstrom exponent decreases from March due to local as well as transported dust from African / Arabian regions through Arabian Sea. Monthly means of SSA show decrease from December to April and the wavelength dependence also indicate the abundance of dust from March to May. Lidar-derived vertical distributions yield minimum during the monsoon months, gradually builds up during the post-monsoon and winter months, and finally peaks during the pre-monsoon months in every year (Devara et al., 2002). The aerosol climatology of optical/radiative parameters and their vertical distribution are used for estimating aerosol radiative forcing (ARF) and atmospheric heating rates by using a discrete-ordinate radiative transfer model (Ricchiazzi et al., 1998, Pandithurai et al. 2004). Details of the experimental methods, data, results of aerosol climatology and implications to radiative forcing and associated heating rates will be presented. References Devara, P

  9. Near-infrared measurement of water temperature near a 1-mm-diameter magnetic sphere and its heat generation rate under induction heating

    Science.gov (United States)

    Kakuta, Naoto; Nishijima, Keisuke; Kondo, Katsuya; Yamada, Yukio

    2017-07-01

    This paper presents a method of measuring the temperature of water near a 1-mm-diameter magnetic sphere under induction heating. The method is based on the temperature dependence of the absorption coefficient of water at a wavelength of 1150 nm. In this study, two-dimensional images of the absorbance, which is the transverse projection of the absorption coefficient of water, were acquired by a near-infrared camera through a telecentric lens, and three-dimensional radial profiles of the temperature were then generated by applying inverse Abel transforms (IATs) to the absorbance profiles. To ensure the spherical symmetry of the temperature and the parallelity of the light rays, which are the conditions necessary to apply an IAT, the onset of free convection and the angles of deflection were evaluated. This paper also presents a method of estimating the heat generation rate in a sphere by fitting the numerical solutions of the thermal conduction equation to the measured temperatures. The temperatures and heat generation rates were observed to change consistently with the changes in the magnetic field intensity.

  10. 76 FR 17473 - Twelfth Meeting: RTCA Special Committee 214: Working Group 78: Standards for Air Traffic Data...

    Science.gov (United States)

    2011-03-29

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 214: Working Group 78: Standards...: Notice of RTCA Special Committee 214: Working Group 78: Standards for Air Traffic Data Communication... Committee 214: Working Group 78: Standards for Air Traffic Data Communication Services. DATES: The...

  11. Comparison of Political Attitudes of German and American Twelfth Year Students: Perspectives on the Rights of Individuals.

    Science.gov (United States)

    Hepburn, Mary A.

    A broad survey of democratic political attitudes of United States and West German students was developed jointly by the Governmental Education Division of the Vinson Institute of Government at the University of Georgia and the Bundeszentrale fur politische Bildung in Bonn. This survey sought to probe twelfth-year students' attitudes toward…

  12. 75 FR 11116 - Certain Pasta from Italy: Notice of Amended Final Results of the Twelfth Antidumping Duty...

    Science.gov (United States)

    2010-03-10

    ... Results of the Twelfth Administrative Review, 75 FR 6352 (February 9, 2010) (Final Results). We are... Antidumping Duty Changed Circumstances Review and Revocation, in Part, 74 FR 41120 (August 14, 2009). The... clarified its ``automatic assessment''' regulation on May 6, 2003 (68 FR 23954). This clarification...

  13. Exploring the Effect of Reader Response Plus on Twelfth Grade Students with Disabilities' Reading Comprehension and Attitudes toward Reading

    Science.gov (United States)

    Granger, Noelle; Black, Alison; Miller, Jane

    2007-01-01

    The purpose of the study was to examine how reader response journals followed by classroom discussion ("Reader Response Plus") contributed to students' reading comprehension and to their attitudes toward reading. The study was conducted in a rural school in upstate New York. The twelfth grade class that participated in the study…

  14. The Twelfth US Air Force. Tactical and Operational Innovations in the Mediterranean Theater of Operations, 1943-1944

    Science.gov (United States)

    2007-02-01

    Husky was a strategic success, contributing to the resignation of Italian dictator Benito Mussolini on 25 July 1943, and the 30 OPERATION HUSKY AND... Mussolini and the surrender of Italy. The Italian capitulation forced the Germans to defend Italy alone with overstretched forces. The Twelfth Air Force

  15. Investigation of char strength and expansion properties of an intumescent coating exposed to rapid heating rates

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2013-01-01

    An efficient and space saving method for passive fire protection is the use of intumescent coatings, which swell when exposed to heat, forming an insulating char layer on top of the virgin coating. Although the temperature curves related to so-called cellulosic fires are often referred to as slow...... heating curves, special cases where the protective char is mechanically damaged and partly removed can cause extremely fast heating of the coating. This situation, for a solvent based intumescent coating, is simulated using direct insertion of free films into a muffle oven. The char formed is evaluated...... with respect to the mechanical resistance against compression, degree of expansion, and residual mass fraction. Experimental results show that when using this type of shock heating, the mechanical resistance of the char against compression cannot meaningfully be correlated to the expansion factor. In addition...

  16. Influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steels

    Science.gov (United States)

    Li, Junru; Liu, Jianjun; Jiang, Bo; Zhang, Chaolei; Liu, Yazheng

    2017-03-01

    The dissolution process of delta ferrites and the influence of high temperature pre-deformation on the dissolution rate of delta ferrites in martensitic heat-resistant steel 10Cr12Ni3Mo2VN were studied by isothermal heating and thermal simulation experiments. The precipitation temperature of delta ferrites in experimental steel is about 1195 °C. M23C6-type carbides incline to precipitate and coarsen at the boundaries of delta ferrites below 930 °C, and can be rapidly dissolved by heating at 1180 °C. The percentage of delta ferrites gradually decreases with heating time. And a Kolmogorov-Johnson-Mehl-Avrami equation was established to describe the dissolution process of delta ferrites at 1180 °C. High temperature pre-deformation can markedly increase the dissolution rate of delta ferrites. Pre-deformation can largely increase the interface area between delta ferrite and matrix and thus increase the unit-time diffusing quantities of alloying elements between delta ferrites and matrix. In addition, high temperature pre-deformation leads to dynamic recrystallization and increases the number of internal grain boundaries in the delta ferrites. This can also greatly increase the diffusing rate of alloying elements. In these cases, the dissolution of delta ferrites can be promoted.

  17. Effects of Pressure on the Properties of Coal Char Under Gasification Conditions at High Initial Heating Rates

    Science.gov (United States)

    Shurtz, Randy Clark

    The effects of elevated pressure and high heating rates on coal pyrolysis and gasification were investigated. A high-pressure flat-flame burner (HPFFB) was designed and built to conduct these studies. The HPFFB was designed to provide an environment with laminar, dispersed entrained flow, with particle heating rates of ˜105 K/s, pressures of up to 15 atm, and gas temperatures of up to 2000 K. Residence times were varied from 30 to 700 ms in this study. Pyrolysis experiments were conducted at particle heating rates of ˜10 5 K/s and maximum gas temperatures of ˜1700 K at pressures of 1 to 15 atm. A new coal swelling correlation was developed that predicts the effects of heating rate, pressure, and coal rank on the swelling ratio at heating rates above ˜104 K/s. A coal swelling rank index system based on 13C-NMR chemical structural parameters was devised. The empirical swelling model requires user inputs of the coal ultimate and proximate analyses and the use of a transient particle energy balance to predict the maximum particle heating rate. The swelling model was used to explain differences in previously reported bituminous coal swelling ratios that were measured in facilities with different heating rates. Char gasification studies by CO2 were conducted on a subbituminous coal and 4 bituminous coals in the HPFFB. Pressures of 5, 10, and 15 atmospheres were used with gas compositions of 20, 40, and 90 mole % CO2. Gas conditions with peak temperatures of 1700 K to 2000 K were used, which resulted in char particle temperatures of 1000 K to 1800 K. Three gasification models were developed to fit and analyze the gasification data. A simple 1 st--order model was used to show that the measured gasification rates were far below the film-diffusion limit. The other two models, designated CCK and CCKN, were based on three versions of the CBK models. CCKN used an nth--order kinetic mechanism and CCK used a semi-global Langmuir-Hinshelwood kinetic mechanism. The two CCK

  18. SISGR - In situ characterization and modeling of formation reactions under extreme heating rates in nanostructured multilayer foils

    Energy Technology Data Exchange (ETDEWEB)

    Hufnagel, Todd C.

    2014-06-09

    Materials subjected to extreme conditions, such as very rapid heating, behave differently than materials under more ordinary conditions. In this program we examined the effect of rapid heating on solid-state chemical reactions in metallic materials. One primary goal was to develop experimental techniques capable of observing these reactions, which can occur at heating rates in excess of one million degrees Celsius per second. One approach that we used is x-ray diffraction performed using microfocused x-ray beams and very fast x-ray detectors. A second approach is the use of a pulsed electron source for dynamic transmission electron microscopy. With these techniques we were able to observe how the heating rate affects the chemical reaction, from which we were able to discern general principles about how these reactions proceed. A second thrust of this program was to develop computational tools to help us understand and predict the reactions. From atomic-scale simulations were learned about the interdiffusion between different metals at high heating rates, and about how new crystalline phases form. A second class of computational models allow us to predict the shape of the reaction front that occurs in these materials, and to connect our understanding of interdiffusion from the atomistic simulations to measurements made in the laboratory. Both the experimental and computational techniques developed in this program are expected to be broadly applicable to a wider range of scientific problems than the intermetallic solid-state reactions studied here. For example, we have already begun using the x-ray techniques to study how materials respond to mechanical deformation at very high rates.

  19. Forecast of Grain Production of China during the Twelfth Five-Year Plan Period

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    According to the latest revised agricultural economic statistical data in China Statistical Yearbook-2010,by selecting and establishing the square root-treated grey model,the empirical analysis and forecast research on the grain output of China from 2011 to 2015 are conducted.The results show that the grain output of China in 2011 will reach 557.739 million tons,and it will break through 600 million tons at 605.617 million tons in 2015.The persistent and stable grain output will ensure that the national economy develops in normal during the twelfth five-year plan period and remit the world grain crisis efficiently;meanwhile,the problem of exorbitant grain prices should be remitted in some level.

  20. Proceedings of the twelfth international symposium on remote sensing of environment

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-01

    This is the third of three volumes of the proceedings of the Twelfth International Symposium on Remote Sensing of Environment, held 20 to 26 April 1978 in Manila, Philippines. This symposium is part of a continuing program investigating current activities in the field of remote sensing. The meeting is intended to promote increased international cooperation in research, development and application of this technology, and to stimulate an exchange of information on all aspects of this multidisciplinary field through the presentation of reports on work planned, in progress or completed. Presentations include those concerned with the utilization of this technology in various national and international programs as well as in numerous applications for monitoring and managing the earth's resources and man's global environment. Ground-based, airborne, and spaceborne sensor systems and both manual and machine-assisted data analysis and interpretation are included. All papers included in their entirety were abstracted and indexed for EDB/ERA.

  1. Special issue “International Geomagnetic Reference Field—the twelfth generation”

    DEFF Research Database (Denmark)

    Thébault, E.; Finlay, C. C.; Toh, H.

    2015-01-01

    is a series of standard mathematical models describing the large scale internal part of the Earth’s magnetic field between epochs 1900.0 and 2015.0 with a forecast to epoch 2020.0. This activity has been maintained since 1968 by a working group of volunteer scientists from several international institutions......This special issue of Earth, Planets and Space, synthesizes the efforts made during the construction of the twelfth generation of the International Geomagnetic Reference Field (IGRF-12) that was released online in December 2014 (http://www.ngdc.noaa.gov/IAGA/vmod/ igrf.html). The IGRF-12...... and Geophysics/Union Internationale de Géodésie et Géophysique (IUGG/UIGG), an “international organization dedicated to advancing, promoting, and communicating knowledge of the Earth system, its space environment, and the dynamical processes causing change” (http://www.iugg.org/)....

  2. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans.

    Science.gov (United States)

    Wingo, Jonathan E; Low, David A; Keller, David M; Brothers, R Matthew; Shibasaki, Manabu; Crandall, Craig G

    2010-11-01

    Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.

  3. Application of multivariate adaptive regression spine-assisted objective function on optimization of heat transfer rate around a cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Prasenjit; Dad, Ajoy K. [Mechanical Engineering Department, National Institute of Technology, Agartala (India)

    2016-12-15

    The present study aims to predict the heat transfer characteristics around a square cylinder with different corner radii using multivariate adaptive regression splines (MARS). Further, the MARS-generated objective function is optimized by particle swarm optimization. The data for the prediction are taken from the recently published article by the present authors [P. Dey, A. Sarkar, A.K. Das, Development of GEP and ANN model to predict the unsteady forced convection over a cylinder, Neural Comput. Appl. (2015). Further, the MARS model is compared with artificial neural network and gene expression programming. It has been found that the MARS model is very efficient in predicting the heat transfer characteristics. It has also been found that MARS is more efficient than artificial neural network and gene expression programming in predicting the forced convection data, and also particle swarm optimization can efficiently optimize the heat transfer rate.

  4. The effect of ultrasound irradiation on the convective heat transfer rate during immersion cooling of a stationary sphere.

    Science.gov (United States)

    Kiani, Hossein; Sun, Da-Wen; Zhang, Zhihang

    2012-11-01

    It has been proven that ultrasound irradiation can enhance the rate of heat transfer processes. The objective of this work was to study the heat transfer phenomenon, mainly the heat exchange at the surface, as affected by ultrasound irradiation around a stationary copper sphere (k=386W m(-1)K(-1), C(p)=384J kg(-1)K(-1), ρ=8660kg m(-3)) during cooling. The sphere (0.01m in diameter) was immersed in an ethylene glycol-water mixture (-10°C) in an ultrasonic cooling system that included a refrigerated circulator, a flow meter, an ultrasound generator and an ultrasonic bath. The temperature of the sphere was recorded using a data logger equipped with a T-type thermocouple in the center of the sphere. The temperature of the cooling medium was also monitored by four thermocouples situated at different places in the bath. The sphere was located at different positions (0.02, 0.04 and 0.06m) above the transducer surface of the bath calculated considering the center of the sphere as the center of the reference system and was exposed to different intensities of ultrasound (0, 120, 190, 450, 890, 1800, 2800, 3400 and 4100W m(-2)) during cooling. The frequency of the ultrasound was 25kHz. It was demonstrated that ultrasound irradiation can increase the rate of heat transfer significantly, resulting in considerably shorter cooling times. Higher intensities caused higher cooling rates, and Nu values were increased from about 23-27 to 25-108 depending on the intensity of ultrasound and the position of the sphere. However, high intensities of ultrasound led to the generation of heat at the surface of the sphere, thus limiting the lowest final temperature achieved. An analytical solution was developed considering the heat generation and was fitted to the experimental data with R(2) values in the range of 0.910-0.998. Visual observations revealed that both cavitation and acoustic streaming were important for heat transfer phenomenon. Cavitation clouds at the surface of the sphere

  5. Thermal Disk Winds in X-Ray Binaries: Realistic Heating and Cooling Rates Give Rise to Slow, but Massive, Outflows

    Science.gov (United States)

    Higginbottom, N.; Proga, D.; Knigge, C.; Long, K. S.

    2017-02-01

    A number of X-ray binaries exhibit clear evidence for the presence of disk winds in the high/soft state. A promising driving mechanism for these outflows is mass loss driven by the thermal expansion of X-ray heated material in the outer disk atmosphere. Higginbottom & Proga recently demonstrated that the properties of thermally driven winds depend critically on the shape of the thermal equilibrium curve, since this determines the thermal stability of the irradiated material. For a given spectral energy distribution, the thermal equilibrium curve depends on an exact balance between the various heating and cooling mechanisms at work. Most previous work on thermally driven disk winds relied on an analytical approximation to these rates. Here, we use the photoionization code cloudy to generate realistic heating and cooling rates which we then use in a 2.5D hydrodynamic model computed in ZEUS to simulate thermal winds in a typical black hole X-ray binary. We find that these heating and cooling rates produce a significantly more complex thermal equilibrium curve, with dramatically different stability properties. The resulting flow, calculated in the optically thin limit, is qualitatively different from flows calculated using approximate analytical rates. Specifically, our thermal disk wind is much denser and slower, with a mass-loss rate that is a factor of two higher and characteristic velocities that are a factor of three lower. The low velocity of the flow—{v}\\max ≃ 200 km s‑1—may be difficult to reconcile with observations. However, the high mass-loss rate—15 × the accretion rate—is promising, since it has the potential to destabilize the disk. Thermally driven disk winds may therefore provide a mechanism for state changes.

  6. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...... and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... and quantitatively with increasing available total heat transfer area. These optimization results allowed to find a “practical” value of the total heat transfer area, i.e. no benefits can be obtained by increasing the available total heat transfer area above this value since the minimal total exergy loss value...

  7. Studies on the Effects of Interphase Heat Exchange during Thermal Explosion in a Combustible Dusty Gas with General Arrhenius Reaction-Rate Laws

    OpenAIRE

    K. S. Adegbie; F. I. Alao

    2012-01-01

    A mathematical model for thermal explosion in a combustible dusty gas containing fuel droplets with general Arrhenius reaction-rate laws, convective and radiative heat losses, and interphase heat exchange between gas and inert solid particles is investigated. The objective of the study is to examine the effects of interphase heat exchange between the gas and solid particles on (i) ignition of reacting gas, (ii) accumulation of heat by the solid particles during combustion process (iii) evapor...

  8. Impact of dust aerosols on the radiative budget, surface heat fluxes, heating rate profiles and convective activity over West Africa during March 2006

    Directory of Open Access Journals (Sweden)

    M. Mallet

    2009-09-01

    Full Text Available The present work analyses the effect of dust aerosols on the surface and top of atmosphere radiative budget, surface temperature, sensible heat fluxes, atmospheric heating rate and convective activity over West Africa. The study is focused on the regional impact of a major dust event over the period of 7–14 March 2006 through numerical simulations performed with the mesoscale, nonhydrostatic atmospheric model MesoNH. Due to its importance on radiative budgets, a specific attention has been paid to the representation of dust single scattering albedo (SSA in MesoNH by using inversions of the AErosol RObotic NETwork (AERONET. The radiative impacts are estimated using two parallel simulations, one including radiative effects of dust and the other without them. The simulations of dust aerosol impacts on the radiative budget indicate remarkable instantaneous (at midday decrease of surface shortwave (SW radiations over land, with regional (9°–17° N, 10° W–20° E mean of −137 W/m2 during the 9 to 12 March period. The surface dimming resulting from the presence of dust is shown to cause important reduction of both surface temperature (up to 4°C and sensible heat fluxes (up to 100 W/m2, which is consistent with experimental observations. At the top of the atmosphere, the SW cooling (regional mean of −12.0 W/m2 induced by mineral dust is shown to dominate the total net (shortwave + longwave effect. The maximum SW heating occurs within the dusty layer with values comprised between 4 and 7° K by day and LW effect results in a cooling of −0.10/−0.20° K by day. Finally, the simulations suggest the decrease of the convective available potential energy (CAPE over the region in the presence of mineral dust.

  9. Interaction of heat production, strain rate and stress power in a plastically deforming body under tensile test

    Science.gov (United States)

    Paglietti, A.

    1982-01-01

    At high strain rates the heat produced by plastic deformation can give rise to a rate dependent response even if the material has rate independent constitutive equations. This effect has to be evaluated when interpreting a material test, or else it could erroneously be ascribed to viscosity. A general thermodynamic theory of tensile testing of elastic-plastic materials is given in this paper; it is valid for large strain at finite strain rates. It enables discovery of the parameters governing the thermodynamic strain rate effect, provides a method for proper interpretation of the results of the tests of dynamic plasticity, and suggests a way of planning experiments in order to detect the real contribution of viscosity.

  10. Interaction of heat production, strain rate and stress power in a plastically deforming body under tensile test

    Science.gov (United States)

    Paglietti, A.

    1982-01-01

    At high strain rates the heat produced by plastic deformation can give rise to a rate dependent response even if the material has rate independent constitutive equations. This effect has to be evaluated when interpreting a material test, or else it could erroneously be ascribed to viscosity. A general thermodynamic theory of tensile testing of elastic-plastic materials is given in this paper; it is valid for large strain at finite strain rates. It enables discovery of the parameters governing the thermodynamic strain rate effect, provides a method for proper interpretation of the results of the tests of dynamic plasticity, and suggests a way of planning experiments in order to detect the real contribution of viscosity.

  11. Subjective ratings and performance in the heat and after sleep deprivation

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ling, S. van; Tan, T.K.

    2013-01-01

    Background: It has been shown that endurance performance after one night of sleep deprivation is not compromised despite the feeling of fatigue and that, in contrast, performance in the heat deteriorates even though people may feel good. However, it is essentially unknown how the estimation of perfo

  12. Apparent activation energy for densification of -Al2O3 powder at constant heating-rate sintering

    Indian Academy of Sciences (India)

    W Q Shao; S O Chen; D Li; H S Cao; Y C Zhang; S S Zhang

    2008-11-01

    The apparent activation energy for densification is a characteristic quantity that elucidates the fundamental diffusion mechanisms during the sintering process. Based on the Arrhenius theory, the activation energy for densification of -Al2O3 at constant heating-rates sintering has been estimated. Sintering of -Al2O3 powder has been executed by the way of a push rod type dilatometer. It is shown that the apparent activation energy does not have a single value but depends directly on the relative density. The apparent activation energy corresponding to lower relative density was higher than that corresponding to higher relative density. In addition, the value of the evaluated activation energy is different at the same density level when the Arrhenius plot involves different heating rates.

  13. Effect of cooling-heating rate on sol-gel transformation of fish gelatin-gum arabic complex coacervate phase.

    Science.gov (United States)

    Anvari, Mohammad; Chung, Donghwa

    2016-10-01

    The objective of this study was to characterize influence of different cooling and heating rates on gelation of fish gelatin (FG)-gum arabic (GA) complex coacervate phase using rheological measurements. For the coacervate phase prepared at 10°C, the gelling temperature, melting temperature, gel strength, and stress relaxation decreased with increasing cooling or heating rate, however, no gelation was observed at the highest cooling rate of 0.05°C/min. Similar trends were obtained for the coacervates phase prepared at 30°C, but the gelation did not occur at a cooling rate of 0.033 or 0.05°C/min. The results indicated that rheological properties of FG-GA coacervate gels were highly dependent to the cooling process, where more thermos-stable and stronger gels formed at slower cooling. This was probably because of higher degree of molecular rearrangements, more hydrogen bindings, and formation of greater junction zones into the gel network at slower cooling rates. However, all of the FG-GA coacervate gels obtained at different cooling rates were classified as a weak physical gel.

  14. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

  15. Prediction of heating rate controlled viscous flow activation energy during spark plasma sintering of amorphous alloy powders

    Science.gov (United States)

    Paul, Tanaji; Harimkar, Sandip P.

    2017-07-01

    The viscous flow behavior of Fe-based amorphous alloy powder during isochronal spark plasma sintering was analyzed under the integrated theoretical background of the Arrhenius and directional structural relaxation models. A relationship between viscous flow activation energy and heating rate was derived. An extension of the pertinent analysis to Ti-based amorphous alloys confirmed the broad applicability of such a relationship for predicting the activation energy for sintering below the glass transition temperature (T g) of the amorphous alloy powders.

  16. Effect of heating rate and kinetic model selection on activation energy of nonisothermal crystallization of amorphous felodipine.

    Science.gov (United States)

    Chattoraj, Sayantan; Bhugra, Chandan; Li, Zheng Jane; Sun, Changquan Calvin

    2014-12-01

    The nonisothermal crystallization kinetics of amorphous materials is routinely analyzed by statistically fitting the crystallization data to kinetic models. In this work, we systematically evaluate how the model-dependent crystallization kinetics is impacted by variations in the heating rate and the selection of the kinetic model, two key factors that can lead to significant differences in the crystallization activation energy (Ea ) of an amorphous material. Using amorphous felodipine, we show that the Ea decreases with increase in the heating rate, irrespective of the kinetic model evaluated in this work. The model that best describes the crystallization phenomenon cannot be identified readily through the statistical fitting approach because several kinetic models yield comparable R(2) . Here, we propose an alternate paired model-fitting model-free (PMFMF) approach for identifying the most suitable kinetic model, where Ea obtained from model-dependent kinetics is compared with those obtained from model-free kinetics. The most suitable kinetic model is identified as the one that yields Ea values comparable with the model-free kinetics. Through this PMFMF approach, nucleation and growth is identified as the main mechanism that controls the crystallization kinetics of felodipine. Using this PMFMF approach, we further demonstrate that crystallization mechanism from amorphous phase varies with heating rate. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  17. GLOBAL EXISTENCE AND CONVERGENCE RATES OF SMOOTH SOLUTIONS FOR THE 3-D COMPRESSIBLE MAGNETOHYDRODYNAMIC EQUATIONS WITHOUT HEAT CONDUCTIVITY

    Institute of Scientific and Technical Information of China (English)

    Zhensheng GAO; Zhong TAN; Guochun WU

    2014-01-01

    In this paper, we are concerned with the global existence and convergence rates of the smooth solutions for the compressible magnetohydrodynamic equations without heat conductivity, which is a hyperbolic-parabolic system. The global solutions are obtained by combining the local existence and a priori estimates if H3-norm of the initial perturbation around a constant states is small enough and its L1-norm is bounded. A priori decay-in-time estimates on the pressure, velocity and magnetic field are used to get the uniform bound of entropy. Moreover, the optimal convergence rates are also obtained.

  18. The effect of heat developed during high strain rate deformation on the constitutive modeling of amorphous polymers

    Science.gov (United States)

    Safari, Keivan H.; Zamani, Jamal; Guedes, Rui M.; Ferreira, Fernando J.

    2016-02-01

    An adiabatic constitutive model is proposed for large strain deformation of polycarbonate (PC) at high strain rates. When the strain rate is sufficiently high such that the heat generated does not have time to transfer to the surroundings, temperature of material rises. The high strain rate deformation behavior of polymers is significantly affected by temperature-dependent constants and thermal softening. Based on the isothermal model which first was introduced by Mulliken and Boyce et al. (Int. J. Solids Struct. 43:1331-1356, 2006), an adiabatic model is proposed to predict the yield and post-yield behavior of glassy polymers at high strain rates. When calculating the heat generated and the temperature changes during the step by step simulation of the deformation, temperature-dependent elastic constants are incorporated to the constitutive equations. Moreover, better prediction of softening phenomena is achieved by the new definition for softening parameters of the proposed model. The constitutive model has been implemented numerically into a commercial finite element code through a user material subroutine (VUMAT). The experimental results, obtained using a split Hopkinson pressure bar, are supported by dynamic mechanical thermal analysis (DMTA) and Decompose/Shift/Reconstruct (DSR) method. Comparison of adiabatic model predictions with experimental data demonstrates the ability of the model to capture the characteristic features of stress-strain curve of the material at very high strain rates.

  19. Correlation of Heating Rates, Crystal Structures, and Microwave Dielectric Properties of Li2ZnTi3O8 Ceramics

    Science.gov (United States)

    Lu, Xuepeng; Zheng, Yong; Huang, Qi; Xiong, Weihao

    2015-11-01

    The correlation of heating rates, crystal structures, and microwave dielectric properties of Li2ZnTi3O8 ceramics was thoroughly investigated. Ionic polarizability, atomic packing fractions, bond strengths, and octahedral distortion of Li2ZnTi3O8 ceramics were calculated on the basis of structure refinement data. The "black core" phenomenon resulting from reduction of Ti4+ ions was observed for Li2ZnTi3O8 ceramic sintered at 1°/min; reduction of Ti4+ ions could be limited by heating more rapidly. For heating rates from 1 to 7°/min, the dielectric constants ( ɛ r) of Li2ZnTi3O8 ceramics were mainly determined by ionic polarizability. The temperature coefficient of the resonant frequency ( τ f ) of Li2ZnTi3O8 ceramics was determined by bond strengths. Li2ZnTi3O8 ceramic sintered at 1°/min had the lowest quality factor ( Q × f); this was related to the high dielectric loss as a result of oxygen vacancies formed by reduction of Ti4+ ions. Q × f values of Li2ZnTi3O8 ceramics also decreased with increasing heating rate from 3 to 7°/min, owing to reduced packing fractions and average grain sizes. Li2ZnTi3O8 ceramic sintered at 3°/min had the optimum microwave dielectric properties of ɛ r = 26.6, Q × f = 83,563 GHz, and τ f = -12.4 ppm/°C.

  20. Impact of the High Flux Isotope Reactor HEU to LEU Fuel Conversion on Cold Source Nuclear Heat Generation Rates

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, David [ORNL

    2014-03-01

    Under the sponsorship of the US Department of Energy National Nuclear Security Administration, staff members at the Oak Ridge National Laboratory have been conducting studies to determine whether the High Flux Isotope Reactor (HFIR) can be converted from high enriched uranium (HEU) fuel to low enriched uranium (LEU) fuel. As part of these ongoing studies, an assessment of the impact that the HEU to LEU fuel conversion has on the nuclear heat generation rates in regions of the HFIR cold source system and its moderator vessel was performed and is documented in this report. Silicon production rates in the cold source aluminum regions and few-group neutron fluxes in the cold source moderator were also estimated. Neutronics calculations were performed with the Monte Carlo N-Particle code to determine the nuclear heat generation rates in regions of the HFIR cold source and its vessel for the HEU core operating at a full reactor power (FP) of 85 MW(t) and the reference LEU core operating at an FP of 100 MW(t). Calculations were performed with beginning-of-cycle (BOC) and end-of-cycle (EOC) conditions to bound typical irradiation conditions. Average specific BOC heat generation rates of 12.76 and 12.92 W/g, respectively, were calculated for the hemispherical region of the cold source liquid hydrogen (LH2) for the HEU and LEU cores, and EOC heat generation rates of 13.25 and 12.86 W/g, respectively, were calculated for the HEU and LEU cores. Thus, the greatest heat generation rates were calculated for the EOC HEU core, and it is concluded that the conversion from HEU to LEU fuel and the resulting increase of FP from 85 MW to 100 MW will not impact the ability of the heat removal equipment to remove the heat deposited in the cold source system. Silicon production rates in the cold source aluminum regions are estimated to be about 12.0% greater at BOC and 2.7% greater at EOC for the LEU core in comparison to the HEU core. Silicon is aluminum s major transmutation product and

  1. Novel Method for Measuring the Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters Based on Artificial Neural Networks and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhijian Liu

    2015-08-01

    Full Text Available The determinations of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, which also wastes too much time and manpower. To address this problem, we propose machine learning models including artificial neural networks (ANNs and support vector machines (SVM to predict the heat collection rate and heat loss coefficient without a direct determination. Parameters that can be easily obtained by “portable test instruments” were set as independent variables, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, final temperature and angle between tubes and ground, while the heat collection rate and heat loss coefficient determined by the detection device were set as dependent variables respectively. Nine hundred fifteen samples from in-service water-in-glass evacuated tube solar water heaters were used for training and testing the models. Results show that the multilayer feed-forward neural network (MLFN with 3 nodes is the best model for the prediction of heat collection rate and the general regression neural network (GRNN is the best model for the prediction of heat loss coefficient due to their low root mean square (RMS errors, short training times, and high prediction accuracies (under the tolerances of 30%, 20%, and 10%, respectively.

  2. Measurement accuracy of heart rate and respiratory rate during graded exercise and sustained exercise in the heat using the Zephyr BioHarness.

    Science.gov (United States)

    Kim, J-H; Roberge, R; Powell, J B; Shafer, A B; Jon Williams, W

    2013-06-01

    The Zephyr BioHarness was tested to determine the accuracy of heart rate (HR) and respiratory rate (RR) measurements during 2 exercise protocols in conjunction with either a laboratory metabolic cart (Vmax) or a previously validated portable metabolic system (K4b2). In one protocol, HR and RR were measured using the BioHarness and Vmax during a graded exercise up to V˙O2max (n=12). In another protocol, HR and RR were measured using the BH and K4b2 during sustained exercise (30% and 50% V˙O2max for 20 min each) in a hot environment (30 °C, 50% relative humidity) (n=6). During the graded exercise, HR but not RR, obtained from the BioHarness was higher compared to the Vmax at baseline and 30% V˙O2max (pexercise in the heat, there were no significant differences between the BioHarness and K4b2 system. Correlation coefficients between the methods were low for HR but moderately to highly correlated (0.49-0.99) for RR. In conclusion, the BioHarness is comparable to Vmax and K4b2 over a wide range of V˙O2 during graded exercise and sustained exercise in the heat.

  3. Roman vs. Arabic Computistics in Twelfth-Century England: A Newly Discovered Source (Collatio Compoti Romani et Arabici).

    Science.gov (United States)

    Nothaft, C Philipp E

    2015-01-01

    A frequently overlooked aspect of the knowledge transfer from Arabic into Latin in the twelfth century is the introduction of the Islamo-Arabic calendar, which confronted Western computists with a radically different scheme of lunar reckoning that was in some ways superior to the 19-year lunar cycle of the Roman Church. One of the earliest sources to properly discuss this new system and compare it to the old one is the anonymous Collatio Compoti Romani et Arabici, found in a manuscript from Tewkesbury Abbey, Gloucestershire. This article contains the first edition and translation of this previously unknown text, preceded by an analysis of its content and sources. As will be argued, the text was written in the second quarter of the twelfth century as a reaction to the astronomical tables of al-Khwāizmī, recently translated by Adelard of Bath, as well as to eclipse observations that had exposed the flaws of the 'Roman' computation.

  4. Self-heating probe instrument and method for measuring high temperature melting volume change rate of material

    Science.gov (United States)

    Wang, Junwei; Wang, Zhiping; Lu, Yang; Cheng, Bo

    2013-03-01

    The castings defects are affected by the melting volume change rate of material. The change rate has an important effect on running safety of the high temperature thermal storage chamber, too. But the characteristics of existing measuring installations are complex structure, troublesome operation and low precision. In order to measure the melting volume change rate of material accurately and conveniently, a self-designed measuring instrument, self-heating probe instrument, and measuring method are described. Temperature in heating cavity is controlled by PID temperature controller; melting volume change rate υ and molten density are calculated based on the melt volume which is measured by the instrument. Positive and negative υ represent expansion and shrinkage of the sample volume after melting, respectively. Taking eutectic LiF+CaF2 for example, its melting volume change rate and melting density at 1 123 K are -20.6% and 2 651 kg·m-3 measured by this instrument, which is only 0.71% smaller than literature value. Density and melting volume change rate of industry pure aluminum at 973 K and analysis pure NaCl at 1 123 K are detected by the instrument too. The measure results are agreed with report values. Measuring error sources are analyzed and several improving measures are proposed. In theory, the measuring errors of the change rate and molten density which are measured by the self-designed instrument is nearly 1/20-1/50 of that measured by the refitted mandril thermal expansion instrument. The self-designed instrument and method have the advantages of simple structure, being easy to operate, extensive applicability for material, relatively high accuracy, and most importantly, temperature and sample vapor pressure have little effect on the measurement accuracy. The presented instrument and method solve the problems of complicated structure and procedures, and large measuring errors for the samples with high vapor pressure by existing installations.

  5. Influence of heat and shear induced protein aggregation on the in vitro digestion rate of whey proteins.

    Science.gov (United States)

    Singh, Tanoj K; Øiseth, Sofia K; Lundin, Leif; Day, Li

    2014-11-01

    Protein intake is essential for growth and repair of body cells, the normal functioning of muscles, and health related immune functions. Most food proteins are consumed after undergoing various degrees of processing. Changes in protein structure and assembly as a result of processing impact the digestibility of proteins. Research in understanding to what extent the protein structure impacts the rate of proteolysis under human physiological conditions has gained considerable interest. In this work, four whey protein gels were prepared using heat processing at two different pH values, 6.8 and 4.6, with and without applied shear. The gels showed different protein network microstructures due to heat induced unfolding (at pH 6.8) or lack of unfolding, thus resulting in fine stranded protein networks. When shear was applied during heating, particulate protein networks were formed. The differences in the gel microstructures resulted in considerable differences in their rheological properties. An in vitro gastric and intestinal model was used to investigate the resulting effects of these different gel structures on whey protein digestion. In addition, the rate of digestion was monitored by taking samples at various time points throughout the in vitro digestion process. The peptides in the digesta were profiled using SDS-polyacrylamide gel electrophoresis, reversed-phase-HPLC and LC-MS. Under simulated gastric conditions, whey proteins in structured gels were hydrolysed faster than native proteins in solution. The rate of peptides released during in vitro digestion differed depending on the structure of the gels and extent of protein aggregation. The outcomes of this work highlighted that changes in the network structure of the protein can influence the rate and pattern of its proteolysis under gastrointestinal conditions. Such knowledge could assist the food industry in designing novel food formulations to control the digestion kinetics and the release of biologically

  6. Influence of body mass loss on changes in heart rate during exercise in the heat: a systematic review.

    Science.gov (United States)

    Adams, William M; Ferraro, Elizabeth M; Huggins, Robert A; Casa, Douglas J

    2014-08-01

    The purpose of this review was to compare the changes in heart rate (HR) for every 1% change in body mass loss (ΔBML) in individuals while exercising in the heat. PubMed, SPORTDiscus, ERIC, CINAHL, and Scopus were searched from the earliest entry to February 2013 using the search terms dehydration, heart rate, and exercise in various combinations. Original research articles that met the following criteria were included: (a) valid measure of HR, (b) exercise in the heat (>26.5° C [79.7 °F]), (c) the level of dehydration reached at least 2%, (d) a between-group comparison (a euhydrated group or a graded dehydration protocol) was evident, and (e) for rehydration protocols, only oral rehydration was considered for inclusion. Twenty articles were included in the final analysis. Mean values and SDs for HR and percentage of body mass loss immediately after exercise were used for this review. The mean change in HR for every 1% ΔBML was 3 b·min-1. In trials where subjects arrived euhydrated and hypohydrated, the mean change in HR for every 1% ΔBML was 3 and 3 b·min-1, respectively. Fixed intensity and variable intensity trials exhibited a mean HR change of 4 and 1 b·min-1, respectively. Exercising in the heat while hypohydrated (≥2%) resulted in an increased HR after exercise. This increase in HR for every 1% ΔBML exacerbates cardiovascular strain in exercising individuals, thus causing decrements in performance. It should be encouraged that individuals should maintain an adequate level of hydration to maximize performance, especially in the heat.

  7. Hebrew and Latin astrology in the twelfth century: the example of the location of pain.

    Science.gov (United States)

    Burnett, Charles

    2010-06-01

    The formative period of Latin and Hebrew astrology occurred virtually simultaneously in both cultures. In the second quarter of the twelfth century the terminology of the subject was established and the textbooks which became authoritative were written. The responsibility for this lay almost entirely with two scholars: John of Seville for the Latins, and Abraham ibn Ezra for the Jews. It is unlikely to have been by coincidence that the same developments in astrology occurred in these two cultures. John of Seville and Abraham ibn Ezra were both brought up within the Islamic culture of Spain, and their astrology was Arabic astrology. Moreover, some scholars have thought that John's origins were Jewish, while Ibn Ezra is known to have collaborated with Latin scholars (whose names are not recorded). It cannot be a coincidence that they forged the science of astrology for their respect co-religionists at almost the same time. Yet, very little research has been done on the possible relations between the two scholars. The purpose of this paper is to begin to explore this relationship, and to illustrate it in particular by their shared doctrine concern the location of pain.

  8. On the determination of the activation energy of a thermoluminescence peak by the two-heating-rates method

    Energy Technology Data Exchange (ETDEWEB)

    Gartia, R.K.; Ingotombi, S.; Singh, Th.S.C.; Mazumdar, P.S. (Manipur Univ. (India). Dept. of Physics)

    1991-01-14

    In this paper precise estimation of the systematic error involved in the determination of the activation energy of a non-first-order thermoluminescence (TL) peak by using the two-heating-rates method (which is strictly valid for a first-order peak) has been made. A new method analogous to this method is proposed, which involves both the peak temperature and peak intensity. The systematic errors involved in both these methods are found to be within the experimental error which one generally encounters in the analysis of TL. The applicability of these findings has been tested by considering a second-order TL peak of limestone. (author).

  9. Influence of heating rate on the temperature of the (alpha+beta)-beta transformation of titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gridnev, V.N.; Ivasishin, O.M.; Markovskii, P.E.

    1985-07-01

    Results of a systematic experimental study of the effect of the heating rate, composition, and structure on the temperature of the (alpha+beta)-beta transformation in titanium alloys VT6, VT14, VT3-1, VT23, and VT22 are presented. It is shown that the transformation temperature of the alloys increases proportionally to the coefficient k-beta, which characterizes the alloy content, and to the size of the alpha-phase grains in the original structure. All other conditions being equal, the transformation is completed sooner in alloys with a spheroidal structure. 8 references.

  10. Optimization of the RF cavity heat load and trip rates for CEBAF at 12 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, He [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Roblin, Yves R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Freyberger, Arne P. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Krafft, Geoffrey A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Terzic, Balsa P. [Old Dominion Univ., Norfolk, VA (United States)

    2017-05-01

    The Continuous Electron Beam Accelerator Facility at JLab has 200 RF cavities in the north linac and the south linac respectively after the 12 GeV upgrade. The purpose of this work is to simultaneously optimize the heat load and the trip rate for the cavities and to reconstruct the pareto-optimal front in a timely manner when some of the cavities are turned down. By choosing an efficient optimizer and strategically creating the initial gradients, the pareto-optimal front for no more than 15 cavities down can be re-established within 20 seconds.

  11. Effect of high heating and cooling rate on interface of diffusion bonded gray cast iron to medium carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Kurt, B. [Firat University, Technical Education Faculty, Metal Department, 23119 Elazig (Turkey); Orhan, N. [Firat University, Technical Education Faculty, Metal Department, 23119 Elazig (Turkey)]. E-mail: norhan@firat.edu.tr; Hascalik, A. [Firat University, Technical Education Faculty, Department of Manufacturing, Elazig (Turkey)

    2007-07-01

    In the present study, a gray cast iron and a medium carbon steel couple were diffusion bonded at the temperatures of 850, 900, 950 and 1000 deg. C under a pressure of 8 MPa for 30 min, and the effects of temperature and high heating and cooling rate on interface formations and microstructure were investigated. After diffusion bonding, scanning electron microscopy, shear test measurements and microhardness measurement of interface region were made. The microstructure at the inside of medium carbon steel of bonded couple consisted of martensite. As a result, from the microstructural observations, a good bonding along the interface of the bonded couples and the interface is free from voids and microcracks.

  12. Modification of atomic physics rates due to nonlocal electron parallel heat transport in divertor plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Allais, F. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Matte, J.P. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada)]. E-mail: matte@inrs-emt.uquebec.ca; Alouani-Bibi, F. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Kim, C.G. [INRS-Energie, Materiaux et Telecommunications, 1650 boul. Lionel Boulet, Varennes, Quebec, J3X 1S2 (Canada); Stotler, D.P. [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Rognlien, T.D. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2005-03-01

    The effect of steep temperature gradients on the rate of ionization of atomic hydrogen is studied numerically with the electron kinetic code 'FPI' [Phys. Rev. Lett. 72 (1994) 1208]. A set of cross sections ['Atomic and Plasma-Material Interaction data for fusion'. Supplement to the journal Nucl. Fusion 4 (1993)] has been used which gives the same rates of radiation, ionization and recombination as in the well known edge modeling codes 'UEDGE' and 'DEGAS' for Maxwellian electron energy distribution functions. For this purpose, 30 energy levels are included in the computation, as stepwise ionization is dominant. The enhancement of the ionization rate by non-Maxwellian effects in the colder part of the plasma is significant.

  13. Disentangling effects of potential shape in the fission rate of heated nuclei

    Science.gov (United States)

    Gontchar, I. I.; Chushnyakova, M. V.; Aktaev, N. E.; Litnevsky, A. L.; Pavlova, E. G.

    2010-12-01

    We have compared the results of dynamical modeling of the fission process with predictions of the Kramers formulas. For the case of large dissipation, there are two of them: the integral rate RI and its approximation RO. As the ratio of the fission barrier height Bf to the temperature T reaches 4, any analytical rate is expected to agree with the dynamical quasistationary rate RD within 2%. The latter has been obtained using numerical modeling with six different potentials. It has been found that the difference between RO and RD sometimes exceeds 20%. The features of the potentials used that are responsible for this disagreement are identified and studied. It is demonstrated that it is RI, not RO, that meets this expectation regardless of the potential used.

  14. Theoretical prediction of the effect of heat transfer parameters on cooling rates of liquid-filled plastic straws used for cryopreservation of spermatozoa.

    Science.gov (United States)

    Sansinen, M; Santos, M V; Zaritzky, N; Baez, R; Chirife, J

    2010-01-01

    Heat transfer plays a key role in cryopreservation of liquid semen in plastic straws. The effect of several parameters on the cooling rate of a liquid-filled polypropylene straw when plunged into liquid nitrogen was investigated using a theoretical model. The geometry of the straw containing the liquid was assimilated as two concentric finite cylinders of different materials: the fluid and the straw; the unsteady-state heat conduction equation for concentric cylinders was numerically solved. Parameters studied include external (convection) heat transfer coefficient (h), the thermal properties of straw manufacturing material and wall thickness. It was concluded that the single most important parameter affecting the cooling rate of a liquid column contained in a straw is the external heat transfer coefficient in LN2. Consequently, in order to attain maximum cooling rates, conditions have to be designed to obtain the highest possible heat transfer coefficient when the plastic straw is plunged in liquid nitrogen.

  15. Influence of quench and heating rates on the ageing response of an Al-Zn-Mg-(Zr) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Deschamps, A.; Brechet, Y. [Ecole Nationale Superieure d`Electrochimie et d`Electrometallurgie, 38 - Saint-Martin-d`Heres (France)

    1998-08-15

    The influence of the quench rate on the microstructure and the ageing response of a Zr-containing Al-Zn-Mg alloy was investigated. It is shown that Al{sub 3}Zr dispersoids are efficient nuclei for precipitation of coarse, equilibrium {eta} precipitates during the quench. Dispersoids are heterogeneously distributed in bands, resulting in bands of quenched-induced precipitates after a slow quench. The ageing response after a slow quench is characterized by various levels of heterogeneities resulting in a `composite` material. On a microscopic scale, quench-induced {eta} precipitates are surrounded by a precipitate-free zone. On a mesoscopic scale, the material is separated in unperturbed regions and regions of high density of coarse precipitates and low density of hardening precipitates. Finally, a slow quench makes the material more sensitive to the heating rate to the ageing temperature, due to slower GP zone precipitation during natural ageing because of annihilation of vacancies during quenching. (orig.) 21 refs.

  16. Aerodynamic pressure and heating-rate distributions in tile gaps around chine regions with pressure gradients at a Mach number of 6.6

    Science.gov (United States)

    Hunt, L. Roane; Notestine, Kristopher K.

    1990-06-01

    Surface and gap pressures and heating-rate distributions were obtained for simulated Thermal Protection System (TPS) tile arrays on the curved surface test apparatus of the Langley 8-Foot High Temperature Tunnel at Mach 6.6. The results indicated that the chine gap pressures varied inversely with gap width because larger gap widths allowed greater venting from the gap to the lower model side pressures. Lower gap pressures caused greater flow ingress from the surface and increased gap heating. Generally, gap heating was greater in the longitudinal gaps than in the circumferential gaps. Gap heating decreased with increasing gap depth. Circumferential gap heating at the mid-depth was generally less than about 10 percent of the external surface value. Gap heating was most severe at local T-gap junctions and tile-to-tile forward-facing steps that caused the greatest heating from flow impingement. The use of flow stoppers at discrete locations reduced heating from flow impingement. The use of flow stoppers at discrete locations reduced heating in most gaps but increased heating in others. Limited use of flow stoppers or gap filler in longitudinal gaps could reduce gap heating in open circumferential gaps in regions of high surface pressure gradients.

  17. Effects of viscous heating and wall-fluid interaction energy on rate-dependent slip behavior of simple fluids

    Science.gov (United States)

    Bao, Luyao; Priezjev, Nikolai V.; Hu, Haibao; Luo, Kai

    2017-09-01

    Molecular dynamics simulations are used to investigate the rate and temperature dependence of the slip length in thin liquid films confined by smooth, thermal substrates. In our setup, the heat generated in a force-driven flow is removed by the thermostat applied on several wall layers away from liquid-solid interfaces. We found that for both high and low wall-fluid interaction (WFI) energies, the temperature of the fluid phase rises significantly as the shear rate increases. Surprisingly, with increasing shear rate, the slip length approaches a constant value from above for high WFI energies and from below for low WFI energies. The two distinct trends of the rate-dependent slip length are rationalized by examining S ( G1) , the height of the main peak of the in-plane structure factor of the first fluid layer (FFL) together with DWF, which is the average distance between the wall and FFL. The results of numerical simulations demonstrate that reduced values of the structure factor, S ( G1) , correlate with the enhanced slip, while smaller distances DWF indicate that fluid atoms penetrate deeper into the surface potential leading to larger friction and smaller slip. Interestingly, at the lowest WFI energy, the combined effect of the increase of S ( G1) and decrease of DWF with increasing shear rate results in a dramatic reduction of the slip length.

  18. Multiplatform analysis of the radiative effects and heating rates for an intense dust storm on 21 June 2007

    Science.gov (United States)

    Naeger, Aaron R.; Christopher, Sundar A.; Johnson, Ben T.

    2013-08-01

    Dust radiative effects and atmospheric heating rates are investigated for a Saharan dust storm on 21 June 2007 using a combination of multiple satellite data sets and ground and aircraft observations as input into a delta-four stream radiative transfer model (RTM). This combines the strengths of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations and CloudSat satellites and in situ aircraft data to characterize the vertical structure of the dust layers (5 km in height with optical depths between 1.5 and 2.0) and underlying low-level water clouds. These observations were used, along with Aerosol Robotic Network retrievals of aerosol optical properties, as input to the RTM to assess the surface, atmosphere, and top of atmosphere (TOA) shortwave aerosol radiative effects (SWAREs). Our results show that the dust TOA SWARE per unit aerosol optical depth was -56 W m-2 in cloud-free conditions over ocean and +74 W m-2 where the dust overlay low-level clouds, and show heating rates greater than 10 K/d. Additional case studies also confirm the results of the 21 June case. This study shows the importance of identifying clouds beneath dust as they can have a significant impact on the radiative effects of dust, and hence assessments of the role of dust aerosol on the energy budget and climate.

  19. A stock-flow consistent input-output model with applications to energy price shocks, interest rates, and heat emissions

    Science.gov (United States)

    Berg, Matthew; Hartley, Brian; Richters, Oliver

    2015-01-01

    By synthesizing stock-flow consistent models, input-output models, and aspects of ecological macroeconomics, a method is developed to simultaneously model monetary flows through the financial system, flows of produced goods and services through the real economy, and flows of physical materials through the natural environment. This paper highlights the linkages between the physical environment and the economic system by emphasizing the role of the energy industry. A conceptual model is developed in general form with an arbitrary number of sectors, while emphasizing connections with the agent-based, econophysics, and complexity economics literature. First, we use the model to challenge claims that 0% interest rates are a necessary condition for a stationary economy and conduct a stability analysis within the parameter space of interest rates and consumption parameters of an economy in stock-flow equilibrium. Second, we analyze the role of energy price shocks in contributing to recessions, incorporating several propagation and amplification mechanisms. Third, implied heat emissions from energy conversion and the effect of anthropogenic heat flux on climate change are considered in light of a minimal single-layer atmosphere climate model, although the model is only implicitly, not explicitly, linked to the economic model.

  20. Heating-Rate-Triggered Carbon-Nanotube-based 3-Dimensional Conducting Networks for a Highly Sensitive Noncontact Sensing Device

    KAUST Repository

    Tai, Yanlong

    2016-01-28

    Recently, flexible and transparent conductive films (TCFs) are drawing more attention for their central role in future applications of flexible electronics. Here, we report the controllable fabrication of TCFs for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks through drop casting lithography of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) ink. How ink formula and baking conditions influence the self-assembled microstructure of the TCFs is discussed. The sensor presents high-performance properties, including a reasonable sheet resistance (2.1 kohm/sq), a high visible-range transmittance (>69%, PET = 90%), and good stability when subjected to cyclic loading (>1000 cycles, better than indium tin oxide film) during processing, when formulation parameters are well optimized (weight ratio of SWCNT to PEDOT:PSS: 1:0.5, SWCNT concentration: 0.3 mg/ml, and heating rate: 36 °C/minute). Moreover, the benefits of these kinds of TCFs were verified through a fully transparent, highly sensitive, rapid response, noncontact moisture-sensing device (5 × 5 sensing pixels).

  1. Influence of substrate heating on excited state generation rates and lifetime in organic solar cells studied by photoinduced absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ziehlke, Hannah; Koerner, Christian; Leo, Karl; Riede, Moritz [IAPP, TU Dresden (Germany); Fitzner, Roland; Reinold, Egon; Baeuerle, Peter [Institut fuer Organische Chemie II und Neue Materialien, Univ. Ulm (Germany)

    2011-07-01

    The performance of organic solar cells crucially depends on the separation of photogenerated excitons into free charge carriers. The dissociation process is sensitively influenced by the nanomorphology of donor (D) and acceptor (A) phases in the photoactive blend layer. Closed percolation paths have to be present such that the created charges are able to leave the blend layer, but also the crystallinity of the D- and the A-phase influence exciton dissociation on a molecular scale. Substrate heating during the vacuum deposition of the active layer is a method to influence the thin film morphology that can lead to improved device performance. We here characterize dicyanovinyl capped quinquethiophenes (D) deposited on substrates at different temperatures (30 and 80 C). Photoinduced absorption spectroscopy (PIA) is used to determine excited state lifetimes and generation rates.We find that efficient charge separation occurs in blends with C{sub 60} (A) and identify the observed excited states as donor cations and triplet excitons. Heating the substrate results in an increased lifetime of the donor cation on the one hand and a decrease in the generation rate of cations on the other hand. The PIA results are complemented by solar cell devices as well as morphological studies.

  2. Spin Dephasing as a Probe of Mode Temperature, Motional State Distributions, and Heating Rates in a 2D Ion Crystal

    CERN Document Server

    Sawyer, Brian C; Bollinger, John J

    2014-01-01

    We employ spin-dependent optical dipole forces to characterize the transverse center-of-mass (COM) motional mode of a two-dimensional Wigner crystal of hundreds of $^9$Be$^+$. By comparing the measured spin dephasing produced by the spin-dependent force with the predictions of a semiclassical dephasing model, we obtain absolute mode temperatures in excellent agreement with both the Doppler laser cooling limit and measurements obtained from a previously published technique (B. C. Sawyer et al. Phys. Rev. Lett. \\textbf{108}, 213003 (2012)). Furthermore, the structure of the dephasing histograms allows for discrimination between initial thermal and coherent states of motion. We also apply the techniques discussed here to measure, for the first time, the ambient heating rate of the COM mode of a 2D Coulomb crystal in a Penning trap. This measurement places an upper limit on the anomalous single-ion heating rate due to electric field noise from the trap electrode surfaces of $\\frac{d\\bar{n}}{dt}\\sim 5$ s$^{-1}$ fo...

  3. Effects of heating and cooling rate on transformation behaviors in weld heat affected zone of low carbon steel; Teitanso koban no yosetsu netsu eikyobu no hentai kyodo ni oyobosu kanetsu reikyaku sokudo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Kanetsuki, Y.; Katsumata, M. [Kobe Steel, Ltd., Kobe (Japan)

    1998-01-25

    Discussions were given on effects of welding heat cycles on transformation behaviors in a weld heat affected zone (HAZ). Test pieces are low-carbon fine ferrite pearlite organization steel sheets, which have been treated with a thermomechanical control process (TMCP). The heat cycling was experimented at a maximum temperature of 1350 degC by using a high-frequency heating coil, heating rates from 0.15 to 200 degC/s, cooling rates from 10 to 80 degC/s at an elevated temperature region (higher than 900 degC), and transformation regions (lower than 900 degC) from 0.5 to 6 degC. A transformation curve in actual welding heat cycling was interpreted from these results. Shear-type inverse transformation (from ferrite to austenite) occurs in a rate region corresponding to the heating rate realized during welding. Austenite containing internal stress and a lower structure formed by this inverse transformation accelerates transformation into grain boundary ferrite (GBF) and acerous ferrite (AF). On the other hand, slow cooling in the elevated temperature region releases the internal stress, restores the lower structure, and suppresses the GBF and AF transformation. The GBF tends to precipitate pearlite in adjacent regions and deteriorates the HAZ tenacity. 17 refs., 8 figs., 1 tab.

  4. Rate of evaporation from the free surface of a heated liquid

    Science.gov (United States)

    Örvös, M.; Szabó, V.; Poós, T.

    2016-11-01

    A method and an experimental setup are developed for determining the intensity of evaporation from the free surface of water. During the measurement, the ambient air velocity and the water temperature can be varied. The mass and temperature of water, as well as the temperature, pressure, and humidity of the ambient air are measured as functions of time. The evaporation rates are calculated from the measured and recorded data in the cases of natural and forced convection.

  5. Comparison of heat transfer in liquid and slush nitrogen by numerical simulation of cooling rates for French straws used for sperm cryopreservation.

    Science.gov (United States)

    Sansinena, M; Santos, M V; Zaritzky, N; Chirife, J

    2012-05-01

    Slush nitrogen (SN(2)) is a mixture of solid nitrogen and liquid nitrogen, with an average temperature of -207 °C. To investigate whether plunging a French plastic straw (commonly used for sperm cryopreservation) in SN(2) substantially increases cooling rates with respect to liquid nitrogen (LN(2)), a numerical simulation of the heat conduction equation with convective boundary condition was used to predict cooling rates. Calculations performed using heat transfer coefficients in the range of film boiling confirmed the main benefit of plunging a straw in slush over LN(2) did not arise from their temperature difference (-207 vs. -196 °C), but rather from an increase in the external heat transfer coefficient. Numerical simulations using high heat transfer (h) coefficients (assumed to prevail in SN(2)) suggested that plunging in SN(2) would increase cooling rates of French straw. This increase of cooling rates was attributed to a less or null film boiling responsible for low heat transfer coefficients in liquid nitrogen when the straw is placed in the solid-liquid mixture or slush. In addition, predicted cooling rates of French straws in SN(2) tended to level-off for high h values, suggesting heat transfer was dictated by heat conduction within the liquid filled plastic straw.

  6. Myowater dynamics and protein secondary structural changes as affected by heating rate in three pork qualities: a combined FT-IR microspectroscopic and 1H NMR relaxometry study.

    Science.gov (United States)

    Wu, Zhiyun; Bertram, Hanne Christine; Böcker, Ulrike; Ofstad, Ragni; Kohler, Achim

    2007-05-16

    The objective of this study was to investigate the influence of heating rate on myowater dynamics and protein secondary structures in three pork qualities by proton NMR T2 relaxation and Fourier transform infrared (FT-IR) microspectroscopy measurements. Two oven temperatures at 100 degrees C and 200 degrees C corresponding to slow and fast heating rates were applied on three pork qualities (DFD, PSE, and normal) to an internal center temperature of 65 degrees C. The fast heating induced a higher cooking loss, particularly for PSE meat. The water proton T21 distribution representing water entrapped within the myofibrillar network was influenced by heating rate and meat quality. Fast heating broadened the T21 distribution and decreased the relaxation times of the T21 peak position for three meat qualities. The changes in T21 relaxation times in meat can be interpreted in terms of chemical and diffusive exchange. FT-IR showed that fast heating caused a higher gain of random structures and aggregated beta-sheets at the expense of native alpha-helixes, and these changes dominate the fast-heating-induced broadening of T21 distribution and reduction in T21 times. Furthermore, of the three meat qualities, PSE meat had the broadest T21 distribution and the lowest T21 times for both heating rates, reflecting that the protein aggregation of PSE caused by heating is more extensive than those of DFD and normal, which is consistent with the IR data. The present study demonstrated that the changes in T2 relaxation times of water protons affected by heating rate and raw meat quality are well related to the protein secondary structural changes as probed by FT-IR microspectroscopy.

  7. Local thermal pressurization triggered by flash heating causes dramatic weakening in water-saturated gouges at subseismic slip rates

    Science.gov (United States)

    Yao, Lu; Ma, Shengli; Shimamoto, Toshihiko; Togo, Tetsuhiro; Chen, Jianye; Kitajima, Hiroko; Wang, Yu; He, Honglin

    2017-04-01

    High-velocity friction studies on water-saturated gouges in recent years have demonstrated that the wet gouges subjected to high-velocity shear tend to have smaller peak and steady-state friction, much shorter slip-weakening distance and lower fracture energy, as compared to the air-dry gouges. Thermal pressurization, compaction-induced pressurization, and flash heating were previously recognized to be the important weakening mechanisms in causing these behaviors. However, in spite of theoretical expectation, there is few evidence to support the occurrence of flash heating in wet gouges, mainly due to the superimposition of multiple weakening mechanisms especially for thermal pressurization. We devised friction experiments to study the role of flash heating in dynamic weakening of water-saturated gouges. In each experiment, we used a pressure vessel to impose a pore pressure of 2.0 MPa on the gouge layer sandwiched between porous ceramics blocks, and applied a long preslide of 1.0 m in displacement before starting the experiment at the target slip rate. By doing so we could (1) suppress rapid thermal pressurization in the bulk gouge layer by means of the designed drained condition and elevated temperature of phase transition of pore water; (2) suppress or even eliminate the pressurization effects due to compaction especially at the very beginning of the experiment. The experiments were performed on a granular gouge (mainly quartz, plagioclase, calcite and illite) and a clay-rich gouge (illite and chlorite ˜58 wt%), which were both collected from the Qingchuan fault of the Longmenshan fault system. For the granular gouge, the steady-state friction coefficients (μss) are 0.39-0.42 at slip rates (V ) of 100 μm/s-10 mm/s; however, at V ≥40 mm/s, the friction coefficients (μ) decrease suddenly at the onset of the slip. For instance, μ reduces by 0.29 within displacement of 0.05-0.08m at V =100 mm/s. For the clay-rich gouge, μss increases from 0.24 to 0.34 as V

  8. Effect of heating rate on mechanical property, microstructure and texture evolution of Al–Mg–Si–Cu alloy during solution treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaofeng; Guo, Mingxing, E-mail: mingxingguo@skl.ustb.edu.cn; Cao, Lingyong; Luo, Jinru; Zhang, Jishan; Zhuang, Linzhong

    2015-01-05

    The effect of heating rate on the mechanical properties, microstructure and texture of Al–Mg–Si–Cu alloy during solution treatment was investigated through tensile testing, scanning electron microscope, scanning transmission electron microscope, metallographic observation and EBSD measurement. The experimental results reveal that there are great differences in the mechanical properties, microstructures and textures after the solution treatment with two different heating rates. Compared with the alloy sheet solution treated with slow heating rate, the alloy sheet solution treated with rapid heating rate possesses weak mechanical property anisotropy and higher average r value. The equiaxed grain is the main recrystallization microstructure for the case of rapid heating rate, while the elongated grain appears in the case of slow heating rate. The texture components are also quite different in the two cases, Cube{sub ND} orientation is the main texture component for the former case, while the latter one includes Cube, R, Goss, P and Brass orientations. The relationship between r value, texture components and microstructure has also been established in this paper.

  9. Mathematical modeling of unsteady response of plate and fin heat exchanger to sudden change in liquid flow rate

    Directory of Open Access Journals (Sweden)

    Korzeń Anna

    2017-01-01

    The results of the numerical simulations of a heat exchanger using experimentally determined air and water-side heat transfer formulas for calculation of heat transfer coefficient were compared with the experimental data. Very good agreement of computation results (i.e. air and water temperature at the outlet of the heat exchanger with the experimental data was obtained.

  10. Rating of an air-to-air heat exchanger in practice; Untersuchung eines Luft-Luft-Waermetauschers unter Praxisbedingungen

    Energy Technology Data Exchange (ETDEWEB)

    Roesmann, Peter; Buescher, Wolfgang [Bonn Univ. (Germany). Abt. ' ' Verfahrenstechnik der Tierischen Erzeugung' '

    2010-07-01

    Barn ventilation is often associated with heat loss. This can be regulated by using appropriate heating technology during the cold season. Air-to-air heat exchanger can be used to recover some of the heat from outlet air. Thereby the system transfers some of the heat from the outlet air to incoming fresh air by heat exchange surfaces. For objective review the DLG has multiple tested this technology on test bed. Long term investigations in practice have taken place rarely. The Institute of Agricultural Engineering, University of Bonn, therefore has tested an recuperative heat exchanger in long term study which was installed in a piglet house. (orig.)

  11. The Weight of Evidence Does Not Support the Listing of Styrene as “Reasonably Anticipated to be a Human Carcinogen” in NTP's Twelfth Report on Carcinogens

    Science.gov (United States)

    Rhomberg, Lorenz R.; Goodman, Julie E.; Prueitt, Robyn L.

    2013-01-01

    Styrene was listed as “reasonably anticipated to be a human carcinogen” in the twelfth edition of the National Toxicology Program's Report on Carcinogens based on what we contend are erroneous findings of limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in experimental animals, and supporting mechanistic data. The epidemiology studies show no consistent increased incidence of, or mortality from, any type of cancer. In animal studies, increased incidence rates of mostly benign tumors have been observed only in certain strains of one species (mice) and at one tissue site (lung). The lack of concordance of tumor incidence and tumor type among animals (even within the same species) and humans indicates that there has been no particular cancer consistently observed among all available studies. The only plausible mechanism for styrene-induced carcinogenesis—a non-genotoxic mode of action that is specific to the mouse lung—is not relevant to humans. As a whole, the evidence does not support the characterization of styrene as “reasonably anticipated to be a human carcinogen,” and styrene should not be listed in the Report on Carcinogens. PMID:23335843

  12. The influence of flow rate on inter-nucleation site heat transport

    Directory of Open Access Journals (Sweden)

    Baltis Coen

    2014-01-01

    Full Text Available The main topic of this paper is the influence of vertically aligned nucleation sites on each other in upward flow boiling. A setup was constructed to facilitate vertical up-flow of deminiralized water under saturation conditions. The main test section is a glass channel with a set of vertically aligned bubble generators. Each bubble generator is operated independently, where power and wall temperature are registered and the vapour bubbles are visualized by a high-speed camera. During the experiments, the downstream bubble generator (BG1 power is kept constant, while the power fed to the upstream bubble generator (BG2 is incrementally increased. Two main trends have been identified. The first trend is dominated by added convection from one site to the other. Both bubble frequency and detachment diameter on BG1 increase with increased power fed to upstream BG2. This effect decreases with increasing inter-site distance and becomes more significant with increasing liquid flow rate. When vapor bubbles start nucleating from BG2, these vapor bubbles inhibit bubble nucleation BG1 and can even lead to deactivation of this nucleation site. This second trend is only weakly dependent on inter-site distance, since the inhibition originates from bubbles flowing past BG1 in close proximity.

  13. Impact of Heating Rate During Exposure of Laser Molten Parts on the Processing Window of PA12 Powder

    Science.gov (United States)

    Drummer, Dietmar; Drexler, Maximilian; Wudy, Katrin

    The additive component manufacturing by selective beam melting of thermoplastic polymer powders can be divided essentially into the following sub-processes: Powder coating, exposure and material consolidation. The mechanical and geometrical properties of a part produced by the selective melting of polymer powders depend toa large extent on these sub-processes. To increase process repeatability basic knowledge about the mutual interactions within the sub-process is of major interest. In the following article the exposure process is focused. Therefore the time dependent energy input into the powder bed is analyzed in its impact on the usable processing window of PA12powder. Thereby parameters like surface temperature, density and strength of molten layers as well as complex body specimens are quantified for varying exposure heating rates. Therefore methods of statistical design of experiments are used. Due to these investigations the derivation of new, the time dependent material behavior of polymers fitting processing strategies is possible.

  14. A critical appraisal of methods of various heating rates for the determination of the activation energy of a thermoluminescence peak

    Energy Technology Data Exchange (ETDEWEB)

    Singh, T.S.C.; Mazumdar, P.S.; Gartia, R.K. (Manipur Univ., Canchipur (India). Dept. of Physics)

    1990-05-14

    An attempt has been made to find out precisely the errors involved in the determination of the activation energy (E) of a thermoluminescence (TL) peak by using the different variants of method of various heating rates. It has been found that for all practical purposes two methods can be considered to be independent of the order of kinetics of the TL process. Finally, the applicability of our findings has been tested experimentally by considering a non-first-order TL peak. The results suggest that the theoretical errors in all the cases are less than the experimental ones and hence these methods can be safely used for all types of TL peaks irrespective of their order of kinetics. (author).

  15. Estimation of the dust production rate from the tungsten armour after repetitive ELM-like heat loads

    Science.gov (United States)

    Pestchanyi, S.; Garkusha, I.; Makhlaj, V.; Landman, I.

    2011-12-01

    Experimental simulations for the erosion rate of tungsten targets under ITER edge-localized mode (ELM)-like surface heat loads of 0.75 MJ m-2 causing surface melting and of 0.45 MJ m-2 without melting have been performed in the QSPA-Kh50 plasma accelerator. Analytical considerations allow us to conclude that for both energy deposition values the erosion mechanism is solid dust ejection during surface cracking under the action of thermo-stress. Tungsten influx into the ITER containment of NW~5×1018 W per medium size ELM of 0.75 MJ m-2 and 0.25 ms time duration has been estimated. The radiation cooling power of Prad=150-300 MW due to such influx of tungsten is intolerable: it should cool the ITER core to 1 keV within a few seconds.

  16. Normal and anomalous heating rate effects on thermoluminescence of Ce-doped ZnB2O4.

    Science.gov (United States)

    Dogan, Tamer; Yüksel, Mehmet; Akça, Sibel; Portakal, Ziyafer Gizem; Balci-Yegen, Sümeyra; Kucuk, Nil; Topaksu, Mustafa

    2017-10-01

    The effect of heating rate (HR) on thermoluminescence (TL) glow curves of 1%, 4%, and 10% Ce(3 +) doped ZnB2O4 phosphors was investigated in detail. The glow peaks are examined and, activation energy (E) and frequency factor (s) are determined by using various heating rate (VHR) method. In the obtained glow curves with nine different HRs between 2 and 10°C/s, it was observed that the TL intensities of the first peaks of all three samples and the second peak of 10% Ce(3 +) doped sample decrease with increasing HR. The decrease in TL intensity was investigated whether it may be due to the presence of thermal quenching or not. On the other hand, the second glow peaks of 1, 4% Ce(3 +) doped ZnB2O4 phosphors show an anomalous TL behavior, which the probability of the radiative processes increases due to recombination of free electrons, so the TL intensity increases with the HR. The graphs of full width at the half maximum (FWHM) versus HR were also plotted to evaluate the influence of HR on TL intensity. In this paper, we suggest that the non-localized Schön - Klasens model may give an explanation for the second peaks of 1, 4% Ce(3 +) doped ZnB2O4 phosphors showing an unexpected increase with the increasing HR. In addition, the calculated E values of all doped phosphors were found similar in the range of 0.47-0.53eV for peak 1 and 0.61-0.66eV for peak 2. However, s values of Ce(3 +) doped ZnB2O4 phosphors were found slightly different according to the dopant amount and the equation used. Furthermore, different amount of Ce(3 +) doped samples indicate the similar properties for the repeated cycles of 5Gy in the same irradiation conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in dry snow

    Directory of Open Access Journals (Sweden)

    A. C. Hansen

    2015-09-01

    Full Text Available The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10–20 K m−1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the effective thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for effective thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  18. A macroscale mixture theory analysis of deposition and sublimation rates during heat and mass transfer in snow

    Directory of Open Access Journals (Sweden)

    A. C. Hansen

    2015-03-01

    Full Text Available The microstructure of a dry alpine snowpack is a dynamic environment where microstructural evolution is driven by seasonal density profiles and weather conditions. Notably, temperature gradients on the order of 10–20 K m−1, or larger, are known to produce a faceted snow microstructure exhibiting little strength. However, while strong temperature gradients are widely accepted as the primary driver for kinetic growth, they do not fully account for the range of experimental observations. An additional factor influencing snow metamorphism is believed to be the rate of mass transfer at the macroscale. We develop a mixture theory capable of predicting macroscale deposition and/or sublimation in a snow cover under temperature gradient conditions. Temperature gradients and mass exchange are tracked over periods ranging from 1 to 10 days. Interesting heat and mass transfer behavior is observed near the ground, near the surface, as well as immediately above and below dense ice crusts. Information about deposition (condensation and sublimation rates may help explain snow metamorphism phenomena that cannot be accounted for by temperature gradients alone. The macroscale heat and mass transfer analysis requires accurate representations of the thermal conductivity and the effective mass diffusion coefficient for snow. We develop analytical models for these parameters based on first principles at the microscale. The expressions derived contain no empirical adjustments, and further, provide self consistent values for thermal conductivity and the effective diffusion coefficient for the limiting cases of air and solid ice. The predicted values for these macroscale material parameters are also in excellent agreement with numerical results based on microscale finite element analyses of representative volume elements generated from X-ray tomography.

  19. Calculating clear-sky radiative heating rates using the Fu-Liou RTM with inputs from observed and reanalyzed profiles

    Science.gov (United States)

    Dolinar, E. K.; Dong, X.; Xi, B.

    2015-12-01

    One-dimensional radiative transfer models (RTM) are a common tool used for calculating atmospheric heating rates and radiative fluxes. In the forward sense, RTMs use known (or observed) quantities of the atmospheric state and surface characteristics to determine the appropriate surface and top-of-atmosphere (TOA) radiative fluxes. The NASA CERES science team uses the modified Fu-Liou RTM to calculate atmospheric heating rates and surface and TOA fluxes using the CERES observed TOA shortwave (SW) and longwave (LW) fluxes as constraints to derive global surface and TOA radiation budgets using a reanalyzed atmospheric state (e.g. temperature and various greenhouse gases) from the newly developed MERRA-2. However, closure studies have shown that using the reanalyzed state as input to the RTM introduces some disparity between the RTM calculated fluxes and surface observed ones. The purpose of this study is to generate a database of observed atmospheric state profiles, from satellite and ground-based sources, at several permanent Atmospheric Radiation Measurement (ARM) Program sites, including the Southern Great Plains (SGP), Northern Slope of Alaska (NSA) and Tropical Western Pacific Nauru (TWP-C2), and Eastern North Atlantic (ENA) permanent facilities. Since clouds are a major modulator of radiative transfer within the Earth's atmosphere, we will focus on the clear-sky conditions in this study, which will set up the baseline for our cloudy studies in the future. Clear-sky flux profiles are calculated using the Edition 4 NASA LaRC modified Fu-Liou RTM. The aforementioned atmospheric profiles generated in-house are used as input into the RTM, as well as from reanalyses. The calculated surface and TOA fluxes are compared with ARM surface measured and CERES satellite observed SW and LW fluxes, respectively. Clear-sky cases are identified by the ARM radar-lidar observations, as well as satellite observations, at the select ARM sites.

  20. Relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production in Nellore steers.

    Science.gov (United States)

    Chaves, A S; Nascimento, M L; Tullio, R R; Rosa, A N; Alencar, M M; Lanna, D P

    2015-10-01

    The objective of this study was to examine the relationship of efficiency indices with performance, heart rate, oxygen consumption, blood parameters, and estimated heat production (EHP) in Nellore steers. Eighteen steers were individually lot-fed diets of 2.7 Mcal ME/kg DM for 84 d. Estimated heat production was determined using oxygen pulse (OP) methodology, in which heart rate (HR) was monitored for 4 consecutive days. Oxygen pulse was obtained by simultaneously measuring HR and oxygen consumption during a 10- to 15-min period. Efficiency traits studied were feed efficiency (G:F) and residual feed intake (RFI) obtained by regression of DMI in relation to ADG and midtest metabolic BW (RFI). Alternatively, RFI was also obtained based on equations reported by the NRC's to estimate individual requirement and DMI (RFI calculated by the NRC [1996] equation [RFI]). The slope of the regression equation and its significance was used to evaluate the effect of efficiency indices (RFI, RFI, or G:F) on the traits studied. A mixed model was used considering RFI, RFI, or G:F and pen type as fixed effects and initial age as a covariate. For HR and EHP variables, day was included as a random effect. There was no relationship between efficiency indices and back fat depth measured by ultrasound or daily HR and EHP ( > 0.05). Because G:F is obtained in relation to BW, the slope of G:F was positive and significant ( consumption per beat was not related to G:F; however, it was lower for RFI- and RFI-efficient steers, and consequently, oxygen volume (mL·min·kg) and OP (μL O·beat·kg) were also lower ( 0.05); however, G:F-efficient steers showed lower hematocrit and hemoglobin concentrations ( consumption and OP were detected, indicating that the OP methodology may be useful to predict growth efficiency.

  1. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling

    Directory of Open Access Journals (Sweden)

    O. Passalacqua

    2017-09-01

    Full Text Available Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF, which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice–bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km  ×  130 km area, with a N–S gradient and with values ranging from 48 to 60 mW m−2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF.

  2. Geothermal flux and basal melt rate in the Dome C region inferred from radar reflectivity and heat modelling

    Science.gov (United States)

    Passalacqua, Olivier; Ritz, Catherine; Parrenin, Frédéric; Urbini, Stefano; Frezzotti, Massimo

    2017-09-01

    Basal melt rate is the most important physical quantity to be evaluated when looking for an old-ice drilling site, and it depends to a great extent on the geothermal flux (GF), which is poorly known under the East Antarctic ice sheet. Given that wet bedrock has higher reflectivity than dry bedrock, the wetness of the ice-bed interface can be assessed using radar echoes from the bedrock. But, since basal conditions depend on heat transfer forced by climate but lagged by the thick ice, the basal ice may currently be frozen whereas in the past it was generally melting. For that reason, the risk of bias between present and past conditions has to be evaluated. The objective of this study is to assess which locations in the Dome C area could have been protected from basal melting at any time in the past, which requires evaluating GF. We used an inverse approach to retrieve GF from radar-inferred distribution of wet and dry beds. A 1-D heat model is run over the last 800 ka to constrain the value of GF by assessing a critical ice thickness, i.e. the minimum ice thickness that would allow the present local distribution of basal melting. A regional map of the GF was then inferred over a 80 km × 130 km area, with a N-S gradient and with values ranging from 48 to 60 mW m-2. The forward model was then emulated by a polynomial function to compute a time-averaged value of the spatially variable basal melt rate over the region. Three main subregions appear to be free of basal melting, two because of a thin overlying ice and one, north of Dome C, because of a low GF.

  3. The Effect of Cumulus Cloud Field Anisotropy on Domain-Averaged Solar Fluxes and Atmospheric Heating Rates

    Science.gov (United States)

    Hinkelman, Laura M.; Evans, K. Franklin; Clothiaux, Eugene E.; Ackerman, Thomas P.; Stackhouse, Paul W., Jr.

    2006-01-01

    Cumulus clouds can become tilted or elongated in the presence of wind shear. Nevertheless, most studies of the interaction of cumulus clouds and radiation have assumed these clouds to be isotropic. This paper describes an investigation of the effect of fair-weather cumulus cloud field anisotropy on domain-averaged solar fluxes and atmospheric heating rate profiles. A stochastic field generation algorithm was used to produce twenty three-dimensional liquid water content fields based on the statistical properties of cloud scenes from a large eddy simulation. Progressively greater degrees of x-z plane tilting and horizontal stretching were imposed on each of these scenes, so that an ensemble of scenes was produced for each level of distortion. The resulting scenes were used as input to a three-dimensional Monte Carlo radiative transfer model. Domain-average transmission, reflection, and absorption of broadband solar radiation were computed for each scene along with the average heating rate profile. Both tilt and horizontal stretching were found to significantly affect calculated fluxes, with the amount and sign of flux differences depending strongly on sun position relative to cloud distortion geometry. The mechanisms by which anisotropy interacts with solar fluxes were investigated by comparisons to independent pixel approximation and tilted independent pixel approximation computations for the same scenes. Cumulus anisotropy was found to most strongly impact solar radiative transfer by changing the effective cloud fraction, i.e., the cloud fraction when the field is projected on a surface perpendicular to the direction of the incident solar beam.

  4. Impact of heat stress on conception rate of dairy cows in the moderate climate considering different temperature-humidity index thresholds, periods relative to breeding, and heat load indices.

    Science.gov (United States)

    Schüller, L K; Burfeind, O; Heuwieser, W

    2014-05-01

    The objectives of this retrospective study were to investigate the relationship between temperature-humidity index (THI) and conception rate (CR) of lactating dairy cows, to estimate a threshold for this relationship, and to identify periods of exposure to heat stress relative to breeding in an area of moderate climate. In addition, we compared three different heat load indices related to CR: mean THI, maximum THI, and number of hours above the mean THI threshold. The THI threshold for the influence of heat stress on CR was 73. It was statistically chosen based on the observed relationship between the mean THI at the day of breeding and the resulting CR. Negative effects of heat stress, however, were already apparent at lower levels of THI, and 1 hour of mean THI of 73 or more decreased the CR significantly. The CR of lactating dairy cows was negatively affected by heat stress both before and after the day of breeding. The greatest negative impact of heat stress on CR was observed 21 to 1 day before breeding. When the mean THI was 73 or more in this period, CR decreased from 31% to 12%. Compared with the average maximum THI and the total number of hours above a threshold of more than or 9 hours, the mean THI was the most sensitive heat load index relating to CR. These results indicate that the CR of dairy cows raised in the moderate climates is highly affected by heat stress.

  5. Studies on the Effects of Interphase Heat Exchange during Thermal Explosion in a Combustible Dusty Gas with General Arrhenius Reaction-Rate Laws

    Directory of Open Access Journals (Sweden)

    K. S. Adegbie

    2012-01-01

    Full Text Available A mathematical model for thermal explosion in a combustible dusty gas containing fuel droplets with general Arrhenius reaction-rate laws, convective and radiative heat losses, and interphase heat exchange between gas and inert solid particles is investigated. The objective of the study is to examine the effects of interphase heat exchange between the gas and solid particles on (i ignition of reacting gas, (ii accumulation of heat by the solid particles during combustion process (iii evaporation of the liquid fuel droplets, and (iv consumption of reacting gas concentration. The equations governing the physical model with realistic assumptions are stated and nondimensionalised leading to an intractable system of first-order coupled nonlinear differential equations, which is not amenable to exact methods of solution. Therefore, we present numerical solutions as well as different qualitative effects of varying interphase heat exchange parameter. Graphs and Table feature prominently to explain the results obtained.

  6. TO DEDUCTION OF MASS FLOW RATE FOR HELICAL HEAT EXCHANGER AT MULTIPLE CROSS-SECTIONS USING CFD

    OpenAIRE

    Surendra Kumar Vishwakarma*, Sanjay Kumbhare, K.K. Thakur

    2016-01-01

    Enhancing the heat transfer by the use of helical coils has been studied and researched by many researchers, because the fluid dynamics inside the pipes of a helical coil heat exchanger offer certain advantages over the straight tubes, shell and tube type heat exchanger, in terms of better heat transfer and mass transfer coefficients. Various configurations of coil structure are possible, and the configuration in which there is a series of vertically stacked helically coiled tubes is the most...

  7. Development of nondestructive evaluation techniques for high-temperature ceramic heat exchanger components. Twelfth quarterly report, July-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-10-01

    Detection of electric-discharge machined notches in a silicon carbide tube by an ultrasonic bore-side probe under microcomputer control has been demonstrated. Use of the reflection mode has been shown to enhance the sensitivity of flaw detection with an acoustic microscope. In this configuration, the transducer and laser-scanned coverslip are both on the tube outer surface, eliminating the need to fill the tube with water. A conceptual design is presented for inspecting tubes up to seven feet long in both through-transmission and reflection-mode configurations. A comparison of NDE techniques for ceramic butt joints showed holographic interferometry to be generally better than dye-penetrant, radiographic, or ultrasonic techniques for characterizing a crack-like inner-wall defect. Pitch-catch and pulse-echo ultrasonic techniques also indicated the presence of an anomaly in the region identified as flawed via holography, while radiographic and penetrant-testing results were ambiguous.

  8. Factorial design for the evaluation of the interaction effect between particle size and heating rate in the kinetic energy of coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Ivonete; Silva, Eugenio A.G.; Mortari, Daniela A.; Crnkovic, Paula M.; Milioli, Fernando E. [University of Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Engineering School. Group of Thermal and Fluids Engineering], Emails: iavila@sc.usp.br, eugenio.silva@usp.br, paulam@sc.usp.br, milioli@sc.usp.br

    2010-07-01

    This paper evaluates the behavior of kinetic energy for different heating rates ({alpha}) and particle sizes of the material in the study of the coal combustion process. It aims to obtain a response surface in a large range of particle size, using heating rates between the minimum and maximum values allowed by the equipment. Therefore it searches for a model to evaluate the interaction effect between particle size and the heating rate and to predict the activation energy of the process studied. The activation energy of the process was determined using the isoconversional model Model Free Kinetics. In this model, the activation energy (E{sub {alpha}}) is obtained as a function of the reaction extent ({alpha}). The subscript in E{sub {alpha}} designates the values related to a given value of conversion ({alpha}). All experiments were conducted in thermogravimetric balance using samples of a Brazilian coal (EC4500) witch average particle size between 163 to 650 {mu}m and heating rates between 10 and 40 deg C min{sup -1} in dynamic atmosphere of air. A central rotatable composite design was applied for the 2{sup 2} factorial design including 4 tests under the axial conditions and 3 repetitions in the central point. As expected, the results show that both the particle size and the heating rate affected significantly the values of activation energy of the coal combustion process obtained by the model used. (author)

  9. Evaluation of three thermal protection systems in a hypersonic high-heating-rate environment induced by an elevon deflected 30 deg

    Science.gov (United States)

    Taylor, A. H.; Jackson, L. R.; Weinstein, I.

    1977-01-01

    Three thermal protection systems proposed for a hypersonic research airplane were subjected to high heating rates in the Langley 8 foot, high temperature structures tunnel. Metallic heat sink (Lockalloy), reusable surface insulation, and insulator-ablator materials were each tested under similar conditions. The specimens were tested for a 10 second exposure on the windward side of an elevon deflected 30 deg. The metallic heat sink panel exhibited no damage; whereas the reusable surface insulation tiles were debonded from the panel and the insulator-ablator panel eroded through its thickness, thus exposing the aluminum structure to the Mach 7 environment.

  10. Satellite NO2 retrievals suggest China has exceeded its NOx reduction goals from the twelfth Five-Year Plan

    Science.gov (United States)

    de Foy, Benjamin; Lu, Zifeng; Streets, David G.

    2016-01-01

    China’s twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NOx) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO2 trends suggested that there was an increase in NO2 columns in most areas from 2005 to around 2011 which was followed by a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NOx emission inventories which were available up until 2014. This shows the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO2 columns. Satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan. PMID:27786278

  11. Satellite NO2 retrievals suggest China has exceeded its NOx reduction goals from the twelfth Five-Year Plan.

    Science.gov (United States)

    de Foy, Benjamin; Lu, Zifeng; Streets, David G

    2016-10-27

    China's twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NOx) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO2 trends suggested that there was an increase in NO2 columns in most areas from 2005 to around 2011 which was followed by a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NOx emission inventories which were available up until 2014. This shows the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO2 columns. Satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan.

  12. Radiative heating rates profiles associated with a springtime case of Bodélé and Sudan dust transport over West Africa

    Directory of Open Access Journals (Sweden)

    C. Lema^itre

    2010-09-01

    Full Text Available The radiative heating rate due to mineral dust over West Africa is investigated using the radiative code STREAMER, as well as remote sensing and in situ observations gathered during the African Monsoon Multidisciplinary Analysis Special Observing Period (AMMA SOP. We focus on two days (13 and 14 June 2006 of an intense and long lasting episode of dust being lifted in remote sources in Chad and Sudan and transported across West Africa in the African easterly jet region, during which airborne operations were conducted at the regional scale, from the southern fringes of the Sahara to the Gulf of Guinea. Profiles of heating rates are computed from airborne LEANDRE 2 (Lidar Embarqué pour l'étude de l'Atmosphère: Nuages Dynamique, Rayonnement et cycle de l'Eau and space-borne CALIOP (Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observations lidar observations using two mineral dust model constrained by airborne in situ data and ground-based sunphotometer obtained during the campaign. Complementary spaceborne observations (from the Moderate-resolution Imaging Spectroradiometer-MODIS and in-situ observations such as dropsondes are also used to take into account the infrared contribution of the water vapour. We investigate the variability of the heating rate on the vertical within a dust plume, as well as the contribution of both shortwave and longwave radiation to the heating rate and the radiative heating rate profiles of dust during daytime and nighttime. The sensitivity of the so-derived heating rate is also analyzed for some key variables for which the associated uncertainties may be large. During daytime, the warming associated with the presence of dust was found to be between 1.5 K day−1 and 4 K day−1, on average, depending on altitude and latitude. Strong warming (i.e. heating rates as high as 8 K day−1 was also observed locally in some limited part of the dust plumes. The uncertainty on the

  13. Utility of birefringence changes due to collagen thermal denaturation rate process analysis: vessel wall temperature estimation for new short term heating balloon angioplasty

    Science.gov (United States)

    Kaneko, Kenji; Shimazaki, Natsumi; Gotoh, Maya; Nakatani, Eriko; Arai, Tsunenori

    2007-02-01

    Our photo thermal reaction heating architecture balloon realizes less than 10 s short term heating that can soften vessel wall collagen without damaging surrounding tissue thermally. New thermal balloon angioplasty, photo-thermo dynamic balloon angioplasty (PTDBA) has experimentally shown sufficient opening with 2 atm low pressure dilation and prevention of chronic phase restenosis and acute phase thrombus in vivo. Even though PTDBA has high therapeutic potential, the most efficient heating condition is still under study, because relationship of treatment and thermal dose to vessel wall is not clarified yet. To study and set the most efficient heating condition, we have been working on establishment of temperature history estimation method from our previous experimental results. Heating target of PTDBA, collagen, thermally denatures following rate process. Denaturation is able to be quantified with measured collagen birefringence value. To express the denaturation with equation of rate process, the following ex vivo experiments were performed. Porcine extracted carotid artery was soaked in two different temperature saline baths to enforce constant temperature heating. Higher temperature bath was set to 40 to 80 degree Celsius and soaking duration was 5 to 40 s. Samples were observed by a polarizing microscope and a scanning electron microscope. The birefringence was measured by polarizing microscopic system using Brace-Koehler compensator 1/30 wavelength. The measured birefringence showed temperature dependency and quite fit with the rate process equation. We think vessel wall temperature is able to be estimated using the birefringence changes due to thermal denaturation.

  14. Research, development, and testing of a prototype two-stage low-input rate oil burner for variable output heating system applications

    Energy Technology Data Exchange (ETDEWEB)

    Krajewski, R.F.; Butcher, T.A. [Brookhaven National Labs., Upton, NY (United States)

    1997-09-01

    The use of a Two-Stage Fan Atomized Oil Burner (TSFAB) in space and water heating applications will have dramatic advantages in terms of it`s potential for a high Annual Fuel Utilization Efficiency (AFUE) and/or Energy Factor (EF) rating for the equipment. While demonstrations of a single rate burner in an actual application have already yielded sufficient confidence that space and domestic heating loads can be met at a single low firing rate, this represents only a narrow solution to the diverse nature of building space heating and domestic water loads that the industry must address. The mechanical development, proposed control, and testing of the Two-Stage burner is discussed in terms of near term and long term goals.

  15. Acute cell death rate of vascular smooth muscle cells during or after short heating up to 20s ranging 50 to 60°C as a basic study of thermal angioplasty

    Science.gov (United States)

    Shinozuka, Machiko; Shimazaki, Natsumi; Ogawa, Emiyu; Machida, Naoki; Arai, Tsunenori

    2014-02-01

    We studied the relations between the time history of smooth muscle cells (SMCs) death rate and heating condition in vitro to clarify cell death mechanism in heating angioplasty, in particular under the condition in which intimal hyperplasia growth had been prevented in vivo swine experiment. A flow heating system on the microscope stage was used for the SMCs death rate measurement during or after the heating. The cells were loaded step-heating by heated flow using a heater equipped in a Photo-thermo dynamic balloon. The heating temperature was set to 37, 50-60°C. The SMCs death rate was calculated by a division of PI stained cell number by Hoechst33342 stained cell number. The SMCs death rate increased 5-10% linearly during 20 s with the heating. The SMCs death rate increased with duration up to 15 min after 5 s heating. Because fragmented nuclei were observed from approximately 5 min after the heating, we defined that acute necrosis and late necrosis were corresponded to within 5 min after the heating and over 5 min after the heating, respectively. This late necrosis is probably corresponding to apoptosis. The ratio of necrotic interaction divided the acute necrosis rate by the late necrosis was calculated based on this consideration as 1.3 under the particular condition in which intimal hyperplasia growth was prevented in vivo previous porcine experiment. We think that necrotic interaction rate is larger than expected rate to obtain intimal hyperplasia suppression.

  16. Sideband cooling an ion to the quantum ground state in a Penning trap with very low heating rate

    CERN Document Server

    Goodwin, J F; Thompson, R C; Segal, D M

    2014-01-01

    We report the laser cooling of a single $^{40}\\text{Ca}^+$ ion in a Penning trap to the motional ground state in one dimension. Cooling is performed in the strong binding limit on the 729-nm electric quadrupole $S_{1/2}\\leftrightarrow D_{5/2}$ transition, broadened by a quench laser coupling the $D_{5/2}$ and $P_{3/2}$ levels. We find the final phonon number to be $\\bar{n}=0.012\\pm0.009$. We measure the heating rate of the trap to be exceptionally low with $\\dot{\\bar{n}}=0.08\\pm 0.12~\\textrm{s}^{-1}$ and a scaled spectral noise density of $\\omega S_{\\omega}<1.6\\times10^{-10}~\\textrm{V}^{2}\\textrm{m}^{-2}\\textrm{Hz}^{-1}\\textrm{s}^{-1}$, which is consistent with the large ion-electrode distance. We perform Rabi oscillations on the sideband-cooled ion and observe a coherence time of $0.7\\pm 0.1~\\textrm{ms}$, noting that the practical performance is limited primarily by the intensity noise of the probe laser.

  17. Measuring the shock-heating rate in the winds of O stars using X-ray line spectra

    CERN Document Server

    Cohen, David H; Gayley, Kenneth G; Owocki, Stanley P; Sundqvist, Jon O; Petit, Veronique; Leutenegger, Maurice A

    2014-01-01

    We present a new method for using measured X-ray emission line fluxes from O stars to determine the shock-heating rate due to instabilities in their radiation-driven winds. The high densities of these winds means that their embedded shocks quickly cool by local radiative emission, while cooling by expansion should be negligible. Ignoring for simplicity any non-radiative mixing or conductive cooling, the method presented here exploits the idea that the cooling post-shock plasma systematically passes through the temperature characteristic of distinct emission lines in the X-ray spectrum. In this way, the observed flux distribution among these X-ray lines can be used to construct the cumulative probability distribution of shock strengths that a typical wind parcel encounters as it advects through the wind. We apply this new method (Gayley 2014) to Chandra grating spectra from five O stars with X-ray emission indicative of embedded wind shocks in effectively single massive stars. Correcting for wind absorption of...

  18. Efficient determination of crystallisation and melting points at low cooling and heating rates with novel computer controlled equipment

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, Philipp [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany); Schweiger, Hans-Georg [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany); Continental Automotive Systems Division, Sickingenstrasse 29-38, D-10553 Berlin (Germany); Wudy, Franz [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany); Gores, Heiner J. [Institut fuer Physikalische und Theoretische Chemie der Universitaet Regensburg, Universitaetsstrasse 31, D-93040 Regensburg (Germany)], E-mail: Heiner.Gores@Chemie.Uni-Regensburg.de

    2008-10-15

    We studied melting and solidification points of 14 pure solvents and two ionic liquids with a recently constructed automatic computer-controlled equipment, which is able to record simultaneously temperature-time functions of up to 30 samples at very low heating and cooling rates down to 1.5 K . h{sup -1}. The effects of viscosity of the studied samples and of carbon fibres as an added crystallisation aid were also investigated. Equilibrium temperatures for the solid-liquid phase transition are in accordance with literature for materials that were often checked, such as acetonitrile, showing the quality of our new equipment, whereas the value of the transition temperature of some other materials differed from published results. It is shown that both the viscosity of the material and carbon fibres as crystallisation aids have an effect on supercooling. The value given for the equilibrium point of the ionic liquid trioctylmethylammonium trifluorocetate T{sub tr} = (285.62 {+-} 0.1) K is new.

  19. Fatigue Crack Growth Rate and Fracture Resistance of Heat Affected Zone of Stainless Steel Narrow Gap Welds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jung; Kim, Min U; Jang, Chang Heui [KAIST, Daejeon (Korea, Republic of); Cho, Sun Young [Korea Laboratory Engineering System, Daejeon (Korea, Republic of); Yang, Jun Seog [KEPCO, Daejeon (Korea, Republic of)

    2011-05-15

    In nuclear power plants, the automated narrow gap welding (NGW) technique has been widely used in joining stainless steel pipes in primary coolant system. As the primary system pipes are subjected to various transients during plant operation, cracks could initiate and propagate that would cause accidents. To prevent the cracking from developing into sudden failure in the primary system, leak-before-break (LBB) design concept has been developed and applied to many nuclear power plants. Meanwhile, to apply the LBB design, mechanical properties of the structural materials of piping systems should be evaluated, especially at weld zone and heat affected zone (HAZ), because mechanical properties within those regions show considerable scatter and spatial differences. In this study, fatigue crack grow rate (FCGR) and fracture resistance of base metal, weld zone, and HAZ of type 316L stainless steel narrow gap welds were performed at plant operating temperature (315 .deg. C) and room temperature. In particular, FCGR and fracture resistance of HAZ were evaluated in detail and compared to those of base metal

  20. A short-term rating method for heat pump heating systems; phase 5: test of the fault diagnosis systems; Kurztestmethode fuer Waermepumpenanlagen; Phase 5: Test der Fehlerdiagnosesysteme

    Energy Technology Data Exchange (ETDEWEB)

    Zogg, D.; Esfandiar, S.

    2001-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) describes the testing phase of a project that developed systems for the operational monitoring and optimisation of heat pump installations along with a diagnosis system for faults. The heat pump is considered as a sub-system. The report describes two monitoring systems and a simulation model that are used to monitor the state of the heat pump both during commissioning as well as during operation. The aim is also to detect faults as early as possible during the whole of the operational life of the installation. A state-orientated approach is propagated as being cheaper than fixed service intervals or repairing after breakdown and standstill. The development of the two monitoring systems called 'HeatWatch' and 'FuzzyWatch' is described. The effort needed for the parametrisation and training of these systems is discussed. The testing of the systems on two test beds using real-life measured values for a single-family home and further simulation data is described and the results listed. The authors state that the monitoring systems can also be used for refrigeration and air-conditioning systems.

  1. The development and initial validation of a virtual dripping sweat rate and a clothing wetness ratio for use in predictive heat strain models

    Science.gov (United States)

    Kubota, H.; Kuwabara, K.; Hamada, Y.

    2014-08-01

    This paper applies the heat balance equation (HBE) for clothed subjects as a linear function of mean skin temperature ( t sk ) by a new sweating efficiency ( η sw ) and an approximation for the thermoregulatory sweat rate. The equation predicting t sk in steady state conditions was derived as the solution of the HBE and used for a predictive heat strain scale. The heat loss from the wet clothing (WCL) area was identified with a new variable of `virtual dripping sweat rate VDSR' ( S wdr ). This is a subject's un-evaporated sweat rate in dry clothing from the regional sweat rate exceeding the maximum evaporative capacity, and adds the moisture to the clothing, reducing the intrinsic clothing insulation. The S wdr allowed a mass balance analysis of the wet clothing area identified as clothing wetness ( w cl ). The w cl was derived by combining the HBE at the WCL surface from which the evaporation rate and skin heat loss from WCL region are given. Experimental results on eight young male subjects wearing typical summer clothing, T-shirt and trousers verified the model for predicting t sk with WCL thermal resistance ( R cl,w ) identified as 25 % of dry clothing ( R cl,d ).

  2. Academic Adjustment of Gifted and Non-Gifted Ninth-, Tenth-, Eleventh-, and Twelfth-Grade Students Placed in Accelerated Mathematics Courses

    Science.gov (United States)

    Speer, Emily M.

    2013-01-01

    This study investigated the academic adjustment of gifted and non-gifted ninth-, tenth-, eleventh-, and twelfth-grade students placed in accelerated mathematics courses. Using Van Eman's research, the investigation of the social and emotional effects of mathematics acceleration through academic adjustment included the following positive indicators…

  3. The Effect of Cooling Rate after Homogenization on the Microstructure and Properties of 2017a Alloy Billets for Extrusion with Solution Heat Treatment on the Press

    Directory of Open Access Journals (Sweden)

    Woźnicki A.

    2016-09-01

    Full Text Available The influence of cooling rate after homogenization on the 2017A alloy microstructure was analysed. The capability of the θ (Al2Cu particles, precipitated during various homogenization coolings, for rapid dissolution was estimated. For this purpose, the DSC test was used to determine the effect of the cooling rate after homogenization on the course of melting during a rapid heating. Moreover, the samples after solution heat treatment (with short time annealing and ageing, were subjected to the microstructure investigations and the microhardness of grains interiors measurements. It was found that cooling after homogenization at 160 °C/h is sufficient for precipitation of fine θ phase particles, which dissolve during the subsequent rapid heating. The cooling at 40 °C/h, causes the precipitation of θ phase in the form of large particles, incapable of further fast dissolution.

  4. Tingkat Insidensi Malaria di Wilayah Pemanasan Kelambu Berinsektisida Tahan Lama dan Wilayah Kontrol (MALARIA INCIDENCE RATE OF HEAT ASSISTED REGENERATION LONG LASTING INSECTICIDAL NETS AREA AND CONTROL

    Directory of Open Access Journals (Sweden)

    Etih Sudarnika

    2012-03-01

    Full Text Available Long lasting insecticidal nets (LLIN is one effective way to prevent malaria. Permethrin treatedLLIN is one type of LLIN which is recommended by WHO. Several studies have shown that these types ofLLIN requiring heat assisted regeneration after washing to enhance the biological activity of insecticidethat contained in the LLIN fibers. This study aimed to compare the incidence rates of malaria in childrenunder five years old who live in the intervention area (where the heat assisted regeneration on LLIN afterwashing was applied and control area (where the heat assisted regeneration on LLIN after washing wasnot applied. Data of malaria cases was collected from laboratory log book at all health centers in BangkaDistrict, in the period of June June 2007 until July 2008. Data were analyzed with Poisson regressionmodels. The results showed that the incidence rate of malaria in children under five years old was notsignificantly different between the treatment and control areas.

  5. The Deformation Rate of Smooth Muscle Cells in Vessel Walls After Short-Duration Heating Dilatation in a Porcine Model Ex Vivo and In Vivo.

    Science.gov (United States)

    Kunio, Mie; Arai, Tsunenori

    2012-09-01

    We have proposed a novel short-duration thermal angioplasty with uniform temperature distribution. Although the dilatation mechanism of our short-duration heating dilatation was reported in our previous study, the influences on smooth muscle cells (SMCs) are not sufficiently understood. We studied the influences on SMCs in terms of shape change and discussed the relationship between the SMCs' shape change and dilatation mechanism ex vivo and in vivo. We found that the SMCs were fixed in the stretched condition after our short-duration heating dilatation both ex vivo and in vivo. The deformation rate of SMCs' shape, measured by the cells' nuclei, was increased with rising balloon maximum temperature (T(balloon)), and the same tendency was observed for the arterial dilatation rate. We hypothesize that the SMCs were fixed in the stretched condition because the arterial dilatation with our short-duration heating dilatation was performed without any plastic deformations of the vessel wall, causing the vessel wall itself to be stretched. We also prospect that the reasons for the positive correlation between the deformation rate of SMCs' shape and T(balloon) are that (i) the area heated over 60 °C was expanded with rising T(balloon), and (ii) the arterial dilatation rate was also increased with rising T(balloon).

  6. Modification of the Ti40Cu36Zr10Pd14 BMG Crystallization Mechanism with Heating Rates 10-140 K/min

    Science.gov (United States)

    Czeppe, T.; Sypien, A.; Wierzbicka-Miernik, A.

    2016-12-01

    The article presents investigations of Ti40Cu36Zr10Pd14 bulk metallic glass crystallization process heated with the rates of 10, 60, 100 and 140 K/min. High heating rates experiments were performed in a new type of differential scanning calorimeter equipped with a fast responding thermal sensor. Phase composition and microstructure were studied with x-ray diffraction and transmission electron microscopy. The observed crystallization proceeded in two separate steps. Applied high rates of heating/cooling resulted in the crystallization of only one CuTi phase, replacing typical multi-phase crystallization. The microstructure after crystallization was polycrystalline with some amount of amorphous phase retained. Kinetic parameters were determined with the use of the Kissinger and Friedman iso-conversional analysis and Matusita-Sakka iso-kinetic model. The kinetic analysis supplies results concerning autocatalytically activated mechanism of primary crystallization with decreasing activation energy and small density of quenched-in nuclei, in good agreement with previous structural investigations. The mechanism of secondary crystallization required dense nuclei site, increasing activation energy and large nucleation frequency. The amorphous phase of Ti40Cu36Zr10Pd14 BMG revealed high thermal stability against crystallization. Application of high heating rates in DSC experiments might be useful for the determination of mechanism and kinetic parameters in investigations of metallic glasses crystallization, giving reasonable results.

  7. Thermoluminescent response of LiF before variation of the heating rate; Respuesta termoluminiscente de LiF ante variacion de la tasa de calentamiento

    Energy Technology Data Exchange (ETDEWEB)

    Barrios, R. [Facultad de Quimica, UAEM, 50000 Toluca, Estado de Mexico (Mexico); Avila, O. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    Comparisons of glow curves of lithium fluoride dosemeters TLD-100 measured to two heating rates with the purpose of quantifying the change in the temperature of the peaks 5 and 7 for the thermoluminescent reader equipment Harshaw 4000 of the thermoluminescence laboratory of the ININ were carried out. (Author)

  8. The effect of nonlinearity in CO2 heating rates on the attribution of stratospheric ozone and temperature changes

    Directory of Open Access Journals (Sweden)

    T. G. Shepherd

    2009-11-01

    Full Text Available An analysis of the attribution of past and future changes in stratospheric ozone and temperature to anthropogenic forcings is presented. The analysis is an extension of the study of Shepherd and Jonsson (2008 who analyzed chemistry-climate simulations from the Canadian Middle Atmosphere Model (CMAM and attributed both past and future changes to changes in the external forcings, i.e. the abundances of ozone-depleting substances (ODS and well-mixed greenhouse gases. The current study is based on a new CMAM dataset and includes two important changes. First, we account for the nonlinear radiative response to changes in CO2. It is shown that over centennial time scales the radiative response in the upper stratosphere to CO2 changes is significantly nonlinear and that failure to account for this effect leads to a significant error in the attribution. To our knowledge this nonlinearity has not been considered before in attribution analysis, including multiple linear regression studies. For the regression analysis presented here the nonlinearity was taken into account by using CO2 heating rate, rather than CO2 abundance, as the explanatory variable. This approach yields considerable corrections to the results of the previous study and can be recommended to other researchers. Second, an error in the way the CO2 forcing changes are implemented in the CMAM was corrected, which significantly affects the results for the recent past. As the radiation scheme, based on Fomichev et al. (1998, is used in several other models we provide some description of the problem and how it was fixed.

  9. Convective heat-transfer rate distributions over a 140 deg blunt cone at hypersonic speeds in different gas environments

    Science.gov (United States)

    Stewart, David A.; Chen, Y. K.

    1993-01-01

    Experiments were conducted in air, CO2, and CO2-argon gas mixtures to obtain heating distribution data over a 140 deg blunt cone with various corner radii. The effect of corner radius on the heating distribution over the forebody of the cone was included in the investigation. These experiments provide data for validation of two-dimensional axisymmetric and three-dimensional Navier-Stokes solutions. Heating distribution data and measured bow shock wave stand-off distances for 0 deg angle of attack were compared with predicted values using a two-dimensional axisymmetric Navier-Stokes code.

  10. The characterization of neural tissue ablation rate and corresponding heat affected zone of a 2 micron Tm3+ doped fiber laser(Conference Presentation)

    Science.gov (United States)

    Marques, Andrew J.; Jivraj, Jamil; Reyes, Robnier; Ramjist, Joel; Gu, Xijia J.; Yang, Victor X. D.

    2017-02-01

    Tissue removal using electrocautery is standard practice in neurosurgery since tissue can be cut and cauterized simultaneously. Thermally mediated tissue ablation using lasers can potentially possess the same benefits but with increased precision. However, given the critical nature of the spine, brain, and nerves, the effects of direct photo-thermal interaction on neural tissue needs to be known, yielding not only high precision of tissue removal but also increased control of peripheral heat damage. The proposed use of lasers as a neurosurgical tool requires that a common ground is found between ablation rates and resulting peripheral heat damage. Most surgical laser systems rely on the conversion of light energy into heat resulting in both desirable and undesirable thermal damage to the targeted tissue. Classifying the distribution of thermal energy in neural tissue, and thus characterizing the extent of undesirable thermal damage, can prove to be exceptionally challenging considering its highly inhomogenous composition when compared to other tissues such as muscle and bone. Here we present the characterization of neural tissue ablation rate and heat affected zone of a 1.94 micron thulium doped fiber laser for neural tissue ablation. In-Vivo ablation of porcine cerebral cortex is performed. Ablation volumes are studied in association with laser parameters. Histological samples are taken and examined to characterize the extent of peripheral heat damage.

  11. Assessment of external heat transfer coefficient during oocyte vitrification in liquid and slush nitrogen using numerical simulations to determine cooling rates.

    Science.gov (United States)

    Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

    2012-01-01

    In oocyte vitrification, plunging directly into liquid nitrogen favor film boiling and strong nitrogen vaporization. A survey of literature values of heat transfer coefficients (h) for film boiling of small metal objects with different geometries plunged in liquid nitrogen revealed values between 125 to 1000 W per per square m per K. These h values were used in a numerical simulation of cooling rates of two oocyte vitrification devices (open-pulled straw and Cryotop), plunged in liquid and slush nitrogen conditions. Heat conduction equation with convective boundary condition was considered a linear mathematical problem and was solved using the finite element method applying the variational formulation. COMSOL Multiphysics was used to simulate the cooling process of the systems. Predicted cooling rates for OPS and Cryotop when cooled at -196 degree C (liquid nitrogen) or -207 degree C (average for slush nitrogen) for heat transfer coefficients estimated to be representative of film boiling, indicated lowering the cooling temperature produces only a maximum 10 percent increase in cooling rates; confirming the main benefit of plunging in slush over liquid nitrogen does not arise from their temperature difference. Numerical simulations also demonstrated that a hypothetical four-fold increase in the cooling rate of vitrification devices when plunging in slush nitrogen would be explained by an increase in heat transfer coefficient. This improvement in heat transfer (i.e., high cooling rates) in slush nitrogen is attributed to less or null film boiling when a sample is placed in slush (mixture of liquid and solid nitrogen) because it first melts the solid nitrogen before causing the liquid to boil and form a film.

  12. Impact of aerosol vertical distribution on aerosol direct radiative effect and heating rate in the Mediterranean region

    Science.gov (United States)

    Pappas, Vasileios; Hatzianastassiou, Nikolaos; Matsoukas, Christos; Koras Carracca, Mario; Kinne, Stefan; Vardavas, Ilias

    2015-04-01

    It is now well-established that aerosols cause an overall cooling effect at the surface and a warming effect within the atmosphere. At the top of the atmosphere (TOA), both positive and negative forcing can be found, depending on a number of other factors, such as surface albedo and relative position of clouds and aerosols. Whilst aerosol surface cooling is important due to its relation with surface temperature and other bio-environmental reasons, atmospheric heating is of special interest as well having significant impacts on atmospheric dynamics, such as formation of clouds and subsequent precipitation. The actual position of aerosols and their altitude relative to clouds is of major importance as certain types of aerosol, such as black carbon (BC) above clouds can have a significant impact on planetary albedo. The vertical distribution of aerosols and clouds has recently drawn the attention of the aerosol community, because partially can account for the differences between simulated aerosol radiative forcing with various models, and therefore decrease the level of our uncertainty regarding aerosol forcing, which is one of our priorities set by IPCC. The vertical profiles of aerosol optical and physical properties have been studied by various research groups around the world, following different methodologies and using various indices in order to present the impact of aerosols on radiation on different altitudes above the surface. However, there is still variability between the published results as to the actual effect of aerosols on shortwave radiation and on heating rate within the atmosphere. This study uses vertical information on aerosols from the Max Planck Aerosol Climatology (MAC-v1) global dataset, which is a combination of model output with quality ground-based measurements, in order to provide useful insight into the vertical profile of atmospheric heating for the Mediterranean region. MAC-v1 and the science behind this aerosol dataset have already

  13. Direct Radiative Effect and Heating Rate of black carbon aerosol: high time resolution measurements and source-identified forcing effects

    Science.gov (United States)

    Ferrero, Luca; Mocnik, Grisa; Cogliati, Sergio; Comi, Alberto; Degni, Francesca; Di Mauro, Biagio; Colombo, Roberto; Bolzacchini, Ezio

    2016-04-01

    Black carbon (BC) absorbs sunlight in the atmosphere heating it. However, up to now, heating rate (HR) calculations from the divergence of the net radiative flux with altitude or from the modelling activity are too sparse. This work fills the aforementioned gap presenting a new methodology based on a full set of physical equations to experimentally determine both the radiative power density absorbed into a ground-based atmospheric layer (ADRE), and the consequent HR induced by the absorptive component of aerosol. In urban context, it is essentially related to the BC. The methodology is also applicable to natural components (i.e. dust) and is obtained solving the first derivative of the main radiative transfer equations. The ADRE and the consequent HR can be determined coupling spectral aerosol absorption measurements with the spectrally resolved measurements of the direct, diffuse downward radiation and the surface reflected radiance components. Moreover, the spectral absorption of BC aerosol allows its source apportionment (traffic and biomass burning (BB)) allowing the same apportionment on HR. This work reports one year of high-time resolution measurements (5 min) of sunlight absorption and HR induced by BC aerosol over Milan. A unique sampling site was set up from March 2015 with: 1) Aethalometer (AE-31, Magee Scientific, 7-λ), 2) the Multiplexer-Radiometer-Irradiometer which detects downward and reflected radiance (350-1000 nm in 3648 spectral bands) coupled with a rotating shadow-band to measure spectrally-resolved global and diffuse radiation (thus direct), 3) a meteorological station (LSI-Lastem) equipped with 3 pyranometers (global, diffuse and refrected radiation; 300-3000 nm), a thermohygrometer, a barometer, an anemometer, 4) condensation and optical particle counters (TSI 3775 and Grimm 1.107), 5) low volume sampler (FAI Hydra dual sampler, PM2.5 and PM10) for sample collection and chemistry determination. Results concerning the radiative power

  14. A new heating strategy in electrothermal atomic absorption spectrometry for better absorbance-time curves at high atomization rate

    Energy Technology Data Exchange (ETDEWEB)

    Torsi, Giancarlo [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy)]. E-mail: giancarlo.torsi@unibo.it; Zattoni, Andrea [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy); Locatelli, Clinio [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy); Valcher, Sergio [Department of Chemistry G. Ciamician, University of Bologna, Via F. Selmi 2, 40126 Bologna (Italy)

    2005-03-31

    The results previously obtained by using fast heating in electrothermal atomic absorption spectrometry are considerably improved by using a new heating sequence which can be summarized as transverse-longitudinal heating mode. The absorbance vs. time curves, obtained with the new heating mode, follow almost perfectly a simple model in which only diffusion is considered as the force acting on the atomic vapor. From the fitting of the experimental absorbance vs. time data points with theoretical values, it is possible to calculate both the absorbance, when all atoms injected are assumed to be present, and their diffusion coefficient. Both values can be calculated by a simple software approach without the operator intervention. The asymptotic absorbance calculated in this way is the maximum absorbance physically obtainable and is the basis for standardless analysis.

  15. Investigation of the influence of groundwater advection on energy extraction rates for sustainable borehole heat exchanger operation

    Science.gov (United States)

    Schelenz, Sophie; Dietrich, Peter; Vienken, Thomas

    2016-04-01

    A sustainable thermal exploitation of the shallow subsurface requires a precise understanding of all relevant heat transport processes. Currently, planning practice of shallow geothermal systems (especially for systems financial investment. Finally, an evaluation approach is presented that classifies relevant heat transport processes according to their Péclet number to enable a first quantitative assessment of the subsurface energy regime and recommend further investigation and planning procedures.

  16. Peripheral Sweat Gland Function, but not Whole-Body Sweat Rate, Increases in Women Following Humid Heat Acclimation

    Science.gov (United States)

    2009-10-01

    Specifically. following heat acclimation (HA) both men and women demonstrate similar reductions in traditional indicators of physiological stress. such as...stress. Environ. Res. 37, 1-11. Lee, J., Bae. J .. Matsumoto, T., Yang. H., Min, Y .. 2009. Tropical malaysians and temperate Koreans exhibit...E.R.W.e. (Eds.). Perspectives in Exercise Sciences and Sports Medicine Volume 6, Exercise. Heat, and Thermoregulation .. Brown Publishers. pp.85-118

  17. Parametric analysis of air–water heat recovery concept applied to HVAC systems: Effect of mass flow rates

    OpenAIRE

    Mohamad Ramadan; Mostafa Gad El Rab; Mahmoud Khaled

    2015-01-01

    In the last three decades, the world has experienced enormous increases in energy and fuel consumption as a consequence of the economic and population growth. This causes renewable energy and energy recovery to become a requirement in building designs rather than option. The present work concerns a coupling between energy recovery and Heating, Ventilating and Air Conditioning HVAC domains and aims to apply heat recovery concepts to HVAC applications working on refrigeration cycles. It particu...

  18. Effects of magnesium-based hydrogen storage materials on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant.

    Science.gov (United States)

    Liu, Leili; Li, Jie; Zhang, Lingyao; Tian, Siyu

    2017-08-24

    MgH2, Mg2NiH4, and Mg2CuH3 were prepared, and their structure and hydrogen storage properties were determined through X-ray photoelectron spectroscopy and thermal analyzer. The effects of MgH2, Mg2NiH4, and Mg2CuH3 on the thermal decomposition, burning rate, and explosive heat of ammonium perchlorate-based composite solid propellant were subsequently studied. Results indicated that MgH2, Mg2NiH4, and Mg2CuH3 can decrease the thermal decomposition peak temperature and increase the total released heat of decomposition. These compounds can improve the effect of thermal decomposition of the propellant. The burning rates of the propellant increased using Mg-based hydrogen storage materials as promoter. The burning rates of the propellant also increased using MgH2 instead of Al in the propellant, but its explosive heat was not enlarged. Nonetheless, the combustion heat of MgH2 was higher than that of Al. A possible mechanism was thus proposed. Copyright © 2017. Published by Elsevier B.V.

  19. Propellant Vaporization as a Criterion for Rocket-Engine Design; Experimental Performance, Vaporization and Heat-Transfer Rates with Various Propellant Combinations

    Science.gov (United States)

    Clark, Bruce J.; Hersch, Martin; Priem, Richard J.

    1959-01-01

    Experimental combustion efficiencies of eleven propellant combinations were determined as a function of chamber length. Efficiencies were measured in terms of characteristic exhaust velocities at three chamber lengths and in terms of gas velocities. The data were obtained in a nominal 200-pound-thrust rocket engine. Injector and engine configurations were kept essentially the same to allow comparison of the performance. The data, except for those on hydrazine and ammonia-fluorine, agreed with predicted results based on the assumption that vaporization of the propellants determines the rate of combustion. Decomposition in the liquid phase may be.responsible for the anomalous behavior of hydrazine. Over-all heat-transfer rates were also measured for each combination. These rates were close to the values predicted by standard heat-transfer calculations except for the combinations using ammonia.

  20. Standard Test Method for Measuring Extreme Heat-Transfer Rates from High-Energy Environments Using a Transient, Null-Point Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers the measurement of the heat-transfer rate or the heat flux to the surface of a solid body (test sample) using the measured transient temperature rise of a thermocouple located at the null point of a calorimeter that is installed in the body and is configured to simulate a semi-infinite solid. By definition the null point is a unique position on the axial centerline of a disturbed body which experiences the same transient temperature history as that on the surface of a solid body in the absence of the physical disturbance (hole) for the same heat-flux input. 1.2 Null-point calorimeters have been used to measure high convective or radiant heat-transfer rates to bodies immersed in both flowing and static environments of air, nitrogen, carbon dioxide, helium, hydrogen, and mixtures of these and other gases. Flow velocities have ranged from zero (static) through subsonic to hypersonic, total flow enthalpies from 1.16 to greater than 4.65 × 101 MJ/kg (5 × 102 to greater than 2 × 104 ...

  1. Validation and recovery rates of an indirect calorimetry headbox system used to measure heat production of cattle

    Science.gov (United States)

    A headbox system was constructed at the University of Nebraska-Lincoln to determine heat production from dairy cattle using indirect calorimetry. The system was designed for use in a tie-stall barn to allow the animal to be comfortable and was mounted on wheels to transport between animals between s...

  2. Increase of production rate of RE-123 film by PLD system with the hot-wall type heating

    Energy Technology Data Exchange (ETDEWEB)

    Kakimoto, K., E-mail: kkakimoto@fujikura.co.j [Fujikura Ltd., 1440 Mutsuzaki, Sakura, Chiba 285-8550 (Japan); Fuji, H.; Igarashi, M.; Hanada, Y.; Hanyu, S.; Hayashida, T.; Tashita, C.; Kutami, H.; Iijima, Y.; Saitoh, T. [Fujikura Ltd., 1440 Mutsuzaki, Sakura, Chiba 285-8550 (Japan)

    2009-10-15

    We have studied two types of heating systems to produce thick GdBa{sub 2}Cu{sub 3}O{sub 7-X} (Gd123) films with high critical current (I{sub c}) stably at a high speed by the PLD method. Material yields of both PLD systems reached about 50-60% by optimization of evaporation condition. Hot-wall heating type (type 2) could fabricate the thicker Gd123 film with the higher I{sub c} compared to contact heating type (type 1) and maximum I{sub c} reached 1040 A at about 6 mum thick. Furthermore, it was estimated that type 2 could fabricate Gd123 film with an I{sub c} of about 700 A at about twice speed compared to type 1. Finally, it was considered that the hot-wall heating type was very advantageous to prepare thick Gd123 film with high I{sub c} at a high speed from the system structure.

  3. The Variations of Thermal Contact Resistance and Heat Transfer Rate of the AlN Film Compositing with PCM

    Directory of Open Access Journals (Sweden)

    Huann-Ming Chou

    2015-01-01

    Full Text Available The electrical industries have been fast developing over the past decades. Moreover, the trend of microelements and packed division multiplex is obviously for the electrical industry. Hence, the high heat dissipative and the electrical insulating device have been popular and necessary. The thermal conduct coefficient of aluminum nitride (i.e., AlN is many times larger than the other materials. Moreover, the green technology of composite with phase change materials (i.e., PCMs is worked as a constant temperature cooler. Therefore, PCMs have been used frequently for saving energy and the green environment. Based on the above statements, it does show great potential in heat dissipative for the AlN film compositing with PCM. Therefore, this paper is focused on the research of thermal contact resistance and heat transfer between the AlN/PCM pairs. According to the experimental results, the heat transfer decreases and the thermal contact resistance increases under the melting process of PCM. However, the suitable parameters such as contact pressures can be used to improve the above defects.

  4. Ignition delays, heats of combustion, and reaction rates of aluminum alkyl derivatives used as ignition and combustion enhancers for supersonic combustors

    Science.gov (United States)

    Ryan, T. W., III; Harlowe, W. W.; Schwab, S.

    1992-01-01

    The work was based on adapting an apparatus and procedure developed at Southwest Research Institute for rating the ignition quality of fuels for diesel engines. Aluminum alkyls and various Lewis-base adducts of these materials, both neat and mixed 50/50 with pure JP-10 hydrocarbon, were injected into the combustion bomb using a high-pressure injection system. The bomb was pre-charged with air that was set at various initial temperatures and pressures for constant oxygen density. The ignition delay times were determined for the test materials at these different initial conditions. The data are presented in absolute terms as well as comparisons with the parent alkyls. The relative heats of reaction of the various test materials were estimated based on a computation of the heat release, using the pressure data recorded during combustion in the bomb. In addition, the global reaction rates for each material were compared at a selected tmperature and pressure.

  5. Optimum bleeding rate of open loop ground source heat pump systems determined by hydrogeological modeling in Korea

    Science.gov (United States)

    Jeon, W. H.; Kim, N.; Lee, J. Y.

    2014-12-01

    This study aims to evaluate the influence of open loop ground source heat pump systems operation on hydrological conditions of aquifer. Test bed is located in Chuncheon, Korea. The step drawdown test was conducted in five stages for 300 minutes. The variation of groundwater levels by open loop ground source heat pump systems operation was estimated using Visual MODFLOW. Transmissivity ranged from 2.02×10-4 to 9.36×10-4, and storage coefficient ranged from 0.00067 to 0.021. The amount of optimum bleeding was calculated to be 240 m3/day. When bleeding will be 50, 90, 240 and 450 m3/day for 5 years, groundwater levels may decrease 1.84, 3.31, 8.89 and 17.0 m, respectively. If the amount of bleeding is 50 m3/day, the influence of bleeding will not reach the boundary regions of the Soyang River after 5 years. Regarding the open loop ground source heat pump system installed at the test bed, the amount of optimum bleeding in accordance with the stand are proposed by the government is 90 m3/day, which is 20% of the 450 m3/day circulation quantity of the system. However, if continuous bleeding of more than 90 m3/day occurs, then the radius of influence is expected to reach the boundary regions of the Soyang River after 5 years. These results indicate that amount of optimum bleeding differ in each open loop ground soured heat pump system. Therefore, the debate for the amount of optimum bleeding in open loop ground source heat pump systems is demanded. This work is supported by the Energy Efficiency and Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No.20123040110010).

  6. Development and numerical/experimental characterization of a lab-scale flat flame reactor allowing the analysis of pulverized solid fuel devolatilization and oxidation at high heating rates

    Science.gov (United States)

    Lemaire, R.; Menanteau, S.

    2016-01-01

    This paper deals with the thorough characterization of a new experimental test bench designed to study the devolatilization and oxidation of pulverized fuel particles in a wide range of operating conditions. This lab-scale facility is composed of a fuel feeding system, the functioning of which has been optimized by computational fluid dynamics. It allows delivering a constant and time-independent mass flow rate of fuel particles which are pneumatically transported to the central injector of a hybrid McKenna burner using a carrier gas stream that can be inert or oxidant depending on the targeted application. A premixed propane/air laminar flat flame stabilized on the porous part of the burner is used to generate the hot gases insuring the heating of the central coal/carrier-gas jet with a thermal gradient similar to those found in industrial combustors (>105 K/s). In the present work, results issued from numerical simulations performed a priori to characterize the velocity and temperature fields in the reaction chamber have been analyzed and confronted with experimental measurements carried out by coupling particle image velocimetry, thermocouple and two-color pyrometry measurements so as to validate the order of magnitude of the heating rate delivered by such a new test bench. Finally, the main features of the flat flame reactor we developed have been discussed with respect to those of another laboratory-scale system designed to study coal devolatilization at a high heating rate.

  7. Development and numerical/experimental characterization of a lab-scale flat flame reactor allowing the analysis of pulverized solid fuel devolatilization and oxidation at high heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, R., E-mail: romain.lemaire@mines-douai.fr; Menanteau, S. [Mines Douai, EI, F-59508 Douai (France)

    2016-01-15

    This paper deals with the thorough characterization of a new experimental test bench designed to study the devolatilization and oxidation of pulverized fuel particles in a wide range of operating conditions. This lab-scale facility is composed of a fuel feeding system, the functioning of which has been optimized by computational fluid dynamics. It allows delivering a constant and time-independent mass flow rate of fuel particles which are pneumatically transported to the central injector of a hybrid McKenna burner using a carrier gas stream that can be inert or oxidant depending on the targeted application. A premixed propane/air laminar flat flame stabilized on the porous part of the burner is used to generate the hot gases insuring the heating of the central coal/carrier-gas jet with a thermal gradient similar to those found in industrial combustors (>10{sup 5} K/s). In the present work, results issued from numerical simulations performed a priori to characterize the velocity and temperature fields in the reaction chamber have been analyzed and confronted with experimental measurements carried out by coupling particle image velocimetry, thermocouple and two-color pyrometry measurements so as to validate the order of magnitude of the heating rate delivered by such a new test bench. Finally, the main features of the flat flame reactor we developed have been discussed with respect to those of another laboratory-scale system designed to study coal devolatilization at a high heating rate.

  8. Measurement Accuracy of Heart Rate and Respiratory Rate during Graded Exercise and Sustained Exercise in the Heat Using the Zephyr BioHarness™

    OpenAIRE

    Kim, J. -H.; Roberge, R.; Powell, J. B.; Shafer, A. B.; Williams, W. Jon

    2012-01-01

    The Zephyr BioHarness™ was tested to determine the accuracy of heart rate (HR) and respiratory rate (RR) measurements during 2 exercise protocols in conjunction with either a laboratory metabolic cart (Vmax) or a previously validated portable metabolic system (K4b2). In one protocol, HR and RR were measured using the BioHarness and Vmax during a graded exercise up to V̇O2max (n = 12). In another protocol, HR and RR were measured using the BH and K4b2 during sustained exercise (30 % and 50 % V...

  9. EFFECTS OF TEST TEMPERATURE AND STRAIN RATE ON THE MECHANICAL PROPERTIES IN AN INTERCRITICALLY HEAT-TREATED BAINITE-TRANSFORMED STEEL

    Institute of Scientific and Technical Information of China (English)

    Z. Li; D. Wu

    2004-01-01

    Larger amount of austenite could be retained in an intercritically heat-treated bainitetransformed steel. The elongation and the strength-ductility balance of the steel could be enhanced considerably due to strain-induced martensite transformation and transformationinduced plasticity (TRIP) of retained austenite. The effects of test temperature and strain rate on the mechanical properties and strain induced transformation behavior of retained austenite in the steel were investigated. Total elongation and strength-ductility balance of the specimen reached maximum when it strained at a strain rate of 2.8×10-4s-1 and at 350℃. The relation between test temperature and tensile properties showed the same tendency at three kinds of strain rates. Flow stress increased considerably with decreasing the strain rate.

  10. Physiological and performance adaptations to an in-season soccer camp in the heat: Associations with heart rate and heart rate variability

    DEFF Research Database (Denmark)

    Buchheit, M; Voss, S C; Nybo, Lars

    2011-01-01

    ) activity, plasma volume (PV) changes, and post-5-min run rate of perceived exertion (RPE) were collected at six occasions in temperate environmental conditions (22°C). Players also performed the yo-yo intermittent recovery test level 1 (Yo-Yo IR1) in the same environmental conditions (22°C), both...

  11. Basal metabolic rate of endotherms can be modeled using heat-transfer principles and physiological concepts: reply to "can the basal metabolic rate of endotherms be explained by biophysical modeling?".

    Science.gov (United States)

    Roberts, Michael F; Lightfoot, Edwin N; Porter, Warren P

    2011-01-01

    Our recent article (Roberts et al. 2010 ) proposes a mechanistic model for the relation between basal metabolic rate (BMR) and body mass (M) in mammals. The model is based on heat-transfer principles in the form of an equation for distributed heat generation within the body. The model can also be written in the form of the allometric equation BMR = aM(b), in which a is the coefficient of the mass term and b is the allometric exponent. The model generates two interesting results: it predicts that b takes the value 2/3, indicating that BMR is proportional to surface area in endotherms. It also provides an explanation of the physiological components that make up a, that is, respiratory heat loss, core-skin thermal conductance, and core-skin thermal gradient. Some of the ideas in our article have been questioned (Seymour and White 2011 ), and this is our response to those questions. We specifically address the following points: whether a heat-transfer model can explain the level of BMR in mammals, whether our test of the model is inadequate because it uses the same literature data that generated the values of the physiological variables, and whether geometry and empirical values combine to make a "coincidence" that makes the model only appear to conform to real processes.

  12. Impact of writing about mathematics in a humanistic context on mathematical self-concept: A twelfth-grade pilot study

    Directory of Open Access Journals (Sweden)

    Kadijević Đorđe M.

    2004-01-01

    Full Text Available As one’s learning results from a complex interplay among his/her cognitive metacognitive and affective domains, the last of which determines the global context where cognition takes place monitored and controlled by metacognition, the learning outcomes may primarily be interpreted in affective terms. Having in mind a strong positive relation between mathematical self and mathematical achievement as well as that a humanistic approach to mathematics teaching/learning would promote higher mathematical self, this study examined whether writing about mathematics in a humanistic context influences mathematical self. This question was answered by comparing mathematical self of twelfth-grade gymnasium (high-school students who wrote their matura works on mathematical themes (N = 10 with that of their classmates who did that in other subjects (N = 72. A higher mathematical self was found for these ten students, which may be commented with "those who chose to write matura works in mathematics were simply those with higher mathematical self and the writing contributed nothing to the outcome". The values of other control variables measured in grades 9-12 evidence that it is more likely that this finding was influenced by the treatment.

  13. Transient LOFA computations for a VHTR using one-twelfth core flow models

    Energy Technology Data Exchange (ETDEWEB)

    Tung, Yu-Hsin, E-mail: touushin@gmail.com [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan (China); Ferng, Yuh-Ming, E-mail: ymferng@ess.nthu.edu.tw [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan (China); Johnson, Richard W., E-mail: rwjohnson@cableone.net [Idaho National Laboratory, Idaho Falls, ID (United States); Chieng, Ching-Chang, E-mail: ccchieng@cityu.edu.hk [Dept of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon (Hong Kong)

    2016-05-15

    Highlights: • Investigation of flow and heat transfer for a 1/12 VHTR core model using CFD. • The high performance computing using ∼531 M sufficient refined mesh. • LOFA transient calculations employ both laminar and turbulence models to characterize natural convection. • The comparisons with small models suggest the need of large flow model. - Abstract: A prismatic gas-cooled very high temperature reactor (VHTR) is being developed under the next generation nuclear program. One of the concerns for the reactor design is the effects of a loss of flow accident (LOFA) where the coolant circulators are lost for some reason, causing a loss of forced coolant flow through the core. In the previous studies, the natural circulation in the whole reactor vessel (RV) was obtained by segmentation strategies if the computational fluid dynamic (CFD) analysis with a sufficiently refined mesh was conducted, due to the limits of computer capability. The computational domains in the previous studies were segmented sections which were small flow region models, such as 1/12 sectors, or a combination of a few number of the 1/12 sector (ranging from 2 to 15) using geometric symmetry, for a full dome region. The present paper investigates the flow and heat transfer for a much larger flow region model, a 1/12 core model, using high performance computing. The computation meshes for 1/12 sector and 1/12 reactor core are of 7.8 M and ∼531 M, respectively. Over 85,000 and 35,000 iterations for steady and transient (100 s) calculations are required to achieve convergence, respectively. ∼0.1 min CPU time was required using 192 computer cores for the 1/12 sector model and ∼1.3 min CPU time using 768 cores in parallel for the 1/12 core model, for every iteration, using ALPS, Advanced Large-scale Parallel Superclusters. For the LOFA transient condition, this study employs both laminar flow and different turbulence models to characterize the phenomenon of natural convection. The

  14. Superheating and melting within aluminum core-oxide shell nanoparticles for a broad range of heating rates: multiphysics phase field modeling.

    Science.gov (United States)

    Hwang, Yong Seok; Levitas, Valery I

    2016-10-19

    The external surface of metallic particles is usually covered by a thin and strong oxide shell, which significantly affects superheating and melting of particles. The effects of geometric parameters and heating rate on characteristic melting and superheating temperatures and melting behavior of aluminum nanoparticles covered by an oxide shell were studied numerically. For this purpose, the multiphysics model that includes the phase field model for surface melting, a dynamic equation of motion, a mechanical model for stress and strain simulations, interface and surface stresses, and the thermal conduction model including thermoelastic and thermo-phase transformation coupling as well as transformation dissipation rate was formulated. Several nontrivial phenomena were revealed. In comparison with a bare particle, the pressure generated in a core due to different thermal expansions of the core and shell and transformation volumetric expansion during melting, increases melting temperatures with the Clausius-Clapeyron factor of 60 K GPa(-1). For the heating rates Q ≤ 10(9) K s(-1), melting temperatures (surface and bulk start and finish melting temperatures, and maximum superheating temperature) are independent of Q. For Q ≥ 10(12) K s(-1), increasing Q generally increases melting temperatures and temperature for the shell fracture. Unconventional effects start for Q ≥ 10(12) K s(-1) due to kinetic superheating combined with heterogeneous melting and geometry. The obtained results are applied to shed light on the initial stage of the melt-dispersion-mechanism of the reaction of Al nanoparticles. Various physical phenomena that promote or suppress melting and affect melting temperatures and temperature of the shell fracture for different heating-rate ranges are summarized in the corresponding schemes.

  15. Effects of heat release rate on NOx time history in diesel combustion; Diesel nensho ni okeru netsu hasseiritsu keika ga NOx nodo rireki ni oyobosu eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, T.; Miwa, K.; Higashida, M. [Tokushima Univ., Tokushima (Japan). Faculty of Engineering; Watanabe, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1996-06-25

    For determining the optimum combination of combustion control techniques to reduce NOx emission from diesel engines, it is important to clarify the effects of each technique not only on the NOx emission but also on its time history during combustion. In this paper, NOx concentration in the combustion chamber of a rapid compression machine has been measured by using a total gas sampling method. In order to elucidate the relation between NOx history and heat release rate, air temperatures nozzle hole size and air motion are varied to control the heat release process. The results show that NOx emission is not solely dependent upon initial combustion. Air utilization in the main diffusive combustion phase has great influence on NOx formation and its decay. NOx formation is accelerated by activation of the initial stage of the main combustion when using a nozzle with small holes. 9 refs., 13 figs.

  16. The heat-compression technique for the conversion of platelet-rich fibrin preparation to a barrier membrane with a reduced rate of biodegradation.

    Science.gov (United States)

    Kawase, Tomoyuki; Kamiya, Mana; Kobayashi, Mito; Tanaka, Takaaki; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

    2015-05-01

    Platelet-rich fibrin (PRF) was developed as an advanced form of platelet-rich plasma to eliminate xenofactors, such as bovine thrombin, and it is mainly used as a source of growth factor for tissue regeneration. Furthermore, although a minor application, PRF in a compressed membrane-like form has also been used as a substitute for commercially available barrier membranes in guided-tissue regeneration (GTR) treatment. However, the PRF membrane is resorbed within 2 weeks or less at implantation sites; therefore, it can barely maintain sufficient space for bone regeneration. In this study, we developed and optimized a heat-compression technique and tested the feasibility of the resulting PRF membrane. Freshly prepared human PRF was first compressed with dry gauze and subsequently with a hot iron. Biodegradability was microscopically examined in vitro by treatment with plasmin at 37°C or in vivo by subcutaneous implantation in nude mice. Compared with the control gauze-compressed PRF, the heat-compressed PRF appeared plasmin-resistant and remained stable for longer than 10 days in vitro. Additionally, in animal implantation studies, the heat-compressed PRF was observed at least for 3 weeks postimplantation in vivo whereas the control PRF was completely resorbed within 2 weeks. Therefore, these findings suggest that the heat-compression technique reduces the rate of biodegradation of the PRF membrane without sacrificing its biocompatibility and that the heat-compressed PRF membrane easily could be prepared at chair-side and applied as a barrier membrane in the GTR treatment.

  17. THE DESIGN ERROR ESTIMATION OF THE HEAT TRANSFER RATE IN THE HEAT PIPE EXCHANGER%热管换热器换热量设计误差估算

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The deviations of the design indexes from the real values of heat exchanger performance are the matters of customer's and manufacturer's common concern. Up till now, the estimating method has no unifiable understanding. For this reason much controversy is often given rise to .This paper presents an estimating method for the design calculation error of the heat transfer rate in the heat pipe exchanger .Error theory is employed to investigate a practical example. Five error sources are found and the results of mathematical analysis are given.%换热器性能的设计指标与实际值偏差的大小,是用户和制造厂家共同关心的问题。目前对这种偏差的估算方法及估算值指标尚未形成共识,因此时有争议发生。本文提出了热管换热器换热量设计误差的估算方法,并以锅炉烟气余热回收装置中的重力热管换热器为例,运用误差理论进行分析计算,找出了产生换热量设计偏差的5个误差源,并给出了计算结果。

  18. Pregnancy rates following timed embryo transfer with fresh or vitrified in vitro produced embryos in lactating dairy cows under heat stress conditions.

    Science.gov (United States)

    Al-Katanani, Y M; Drost, M; Monson, R L; Rutledge, J J; Krininger, C E; Block, J; Thatcher, W W; Hanse, P J

    2002-07-01

    Timed embryo transfer (TET) using in vitro produced (IVP) embryos without estrus detection can be used to reduce adverse effects of heat stress on fertility. One limitation is the poor survival of IVP embryos after cryopreservation. Objectives of this study were to confirm beneficial effects of TET on pregnancy rate during heat stress as compared to timed artificial insemination (TAI), and to determine if cryopreservation by vitrification could improve survival of IVP embryos transferred to dairy cattle under heat stress conditions. For vitrified embryos (TET-V), a three-step pre-equilibration procedure was used to vitrify excellent and good quality Day 7 IVP Holstein blastocysts. For fresh IVP embryos (TET-F), Holstein oocytes were matured and fertilized; resultant embryos were cultured in modified KSOM for 7 days using the same method as for production of vitrified embryos. Excellent and good quality blastocysts on Day 7 were transported to the cooperating dairy in a portable incubator. Nonpregnant, lactating Holsteins (n = 155) were treated with GnRH (100 microg, i.m., Day 0), followed 7 days later by prostaglandin F2alpha (PGF2alpha, 25 mg, i.m.) and GnRH (100 microg) on Day 9. Cows in the TAI treatment (n = 68) were inseminated the next day (Day 10) with semen from a single bull that also was used to produce embryos. Cows in the other treatments (n = 33 for TET-F; n = 54 for TET-V) received an embryo on Day 17 (i.e. Day 7 after anticipated ovulation and Day 8 after second GnRH treatment). The proportion of cows that responded to synchronization based on plasma progesterone concentrations on Day 10 and Day 17 was 67.7%. Pregnancy rate for all cows on Day 45 was higher (P cows responding to synchronization, pregnancy rate was also higher (P cows producing more milk had lower (P cows producing less milk. In conclusion, ET of fresh IVP embryos can improve pregnancy rate under heat stress conditions, but pregnancy rate following transfer of vitrified embryos was no

  19. Determination of convective diffusion heat/mass transfer rates to burner rig test targets comparable in size to cross-stream jet diameter

    Science.gov (United States)

    Gokoglu, S. A.; Santoro, G. J.

    1985-01-01

    Two sets of experiments have been performed to be able to predict the convective diffusion heat/mass transfer rates to a cylindrical target whose height and diameter are comparable to, but less than, the diameter of the circular cross-stream jet, thereby simulating the same geometric configuration as a typical burner rig test specimen located in the cross-stream of the combustor exit nozzle. The first set exploits the naphthalene sublimation technique to determine the heat/mass transfer coefficient under isothermal conditions for various flow rates (Reynolds numbers). The second set, conducted at various combustion temperatures and Reynolds numbers, utilized the temperature variation along the surface of the above-mentioned target under steady-state conditions to estimate the effect of cooling (dilution) due to the entrainment of stagnant room temperature air. The experimental information obtained is used to predict high temperature, high velocity corrosive salt vapor deposition rates in burner rigs on collectors that are geometrically the same. The agreement with preliminary data obtained from Na2SO4 vapor deposition experiments is found to be excellent.

  20. Efficient ground-state cooling of an ion in a large room-temperature linear Paul trap with a sub-Hertz heating rate

    DEFF Research Database (Denmark)

    Poulsen, Gregers; Miroshnychenko, Yevhen; Drewsen, Michael

    2012-01-01

    We demonstrate efficient resolved sideband laser cooling (99±1% ground-state population) of a single 40Ca+ ion in a large linear Paul trap (electrode spacing of 7 mm) operated at an rf drive frequency of just 3.7 MHz. For ion oscillation frequencies in the range 280–585 kHz, heating rates below...... or about one motional quantum per second have been measured at room temperature. The results, obtained under these unconventional sideband cooling conditions, pave the way for a range of new types of cold ion experiments, including spectroscopy of molecular ions as well as ultracold chemistry....

  1. Investigation of the heating rate dependency associated with the loss of crystalline structure in sucrose, glucose, and fructose using a thermal analysis approach (part I).

    Science.gov (United States)

    Lee, Joo Won; Thomas, Leonard C; Schmidt, Shelly J

    2011-01-26

    Thermodynamic melting occurs at a single, time-independent temperature with a constant enthalpy value. However, substantial variation in the melting parameters (T(m onset), T(m peak), and ΔH) for sucrose, glucose, and fructose has been reported in the literature. Although a number of explanations have been put forth, they do not completely account for the observed variation. Thus, this research was performed to elucidate the fundamental mechanism underlying the loss of crystalline structure in the sugars using both thermal (Part I) and chemical (Part II) analysis approaches. A strong heating rate dependency observed in the melting parameters for the sugars implies the occurrence of a kinetic process during the loss of crystalline structure. The difference in heat capacity and modulated heat flow amplitude in the stepwise quasi-isothermal modulated differential scanning calorimetry experiments for the sugars compared to indium and mannitol (thermodynamic melting comparison materials) strongly suggests thermal decomposition as the kinetic process responsible for the loss of crystalline structure, which is the critical difference between our conclusion and others. We propose the term "apparent melting" to distinguish the loss of crystalline structure due to a kinetic process, such as thermal decomposition, from thermodynamic melting.

  2. High-rate continuous hydrogen production by Thermoanaerobacterium thermosaccharolyticum PSU-2 immobilized on heat-pretreated methanogenic granules

    DEFF Research Database (Denmark)

    O-Thong, Sompong; Prasertsan, P.; Karakashev, Dimitar Borisov;

    2008-01-01

    as carrier to immobilize T. thermosaccharolyticum strain PSU-2 in UASB reactor operated at a hydraulic retention time (HRT) ranging from 0.75 to 24h and corresponding sucrose loading rate from 58.5 to 2.4 mmol sucrose l(-1)h(-1). In comparison with hydrogen production rate of 12.1 mmol H(2)l(-1)h(-1......) obtained by carrier-free reactor upflow anaerobic (UA) system, a greatly improved hydrogen production rate up to 152 mmol H(2)l(-1)h(-1) was demonstrated by the granular cells in UASB system. The biofilm of T. thermosaccharolyticum strain PSU-2 developed on treated methanogenic granules in UASB reactor...... substantially enhanced biomass retention (3 times), and production of hydrogen (12 times) compared to carrier-free reactor. It appears to be the most preferred process for highly efficient dark fermentative hydrogen production from sugar containing wastewater under thermophilic conditions. (C) 2008...

  3. Fiscal transfers based on inputs or outcomes? Lessons from the Twelfth and Thirteenth Finance Commission in India.

    Science.gov (United States)

    Fan, Victoria Y; Iyer, Smriti; Kapur, Avani; Mahbub, Rifaiyat; Mukherjee, Anit

    2017-08-30

    There is limited empirical evidence about the efficacy of fiscal transfers for a specific purpose, including for health which represents an important source of funds for the delivery of public services especially in large populous countries such as India. To examine two distinct methodologies for allocating specific-purpose centre-to-state transfers, one using an input-based formula focused on equity and the other using an outcome-based formula focused on performance. We examine the Twelfth Finance Commission (12FC)'s use of Equalization Grants for Health (EGH) as an input-based formula and the Thirteenth Finance Commission (13FC)'s use of Incentive Grants for Health (IGH) as an outcome-based formula. We simulate and replicate the allocation of these two transfer methodologies and examine the consequences of these fiscal transfer mechanisms. The EGH placed conditions for releasing funds, but states varied in their ability to meet those conditions, and hence their allocations varied, eg, Madhya Pradesh received 100% and Odisha 67% of its expected allocation. Due to the design of the IGH formula, IGH allocations were unequally distributed and highly concentrated in 4 states (Manipur, Sikkim, Tamil Nadu, Nagaland), which received over half the national IGH allocation. The EGH had limited impact in achieving equalization, whereas the IGH rewards were concentrated in states which were already doing better. Greater transparency and accountability of centre-to-state allocations and specifically their methodologies are needed to ensure that allocation objectives are aligned to performance. © 2017 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons Ltd.

  4. 微晶无机保温材料对提高烤房热能利用率的影响%Effect of Microcrystal Inorganic Heat Preservation Material on Improving the Utilization Rate of Heat Energy of Curing Barn

    Institute of Scientific and Technical Information of China (English)

    郭婷; 耿素祥; 李文; 李良勇; 彭良; 刘小斌; 余金龙

    2016-01-01

    Single factor experiment design was used to study the effect of microcrystal inorganic heat preservation material on improving the utilization rate of heat energy of curing barn, saving the cost of flue cured tobacco and improving the quality of the cured tobacco leaves. The results showed that: compared with the control, the lower cost of flue cured tobacco with adding microcrystal inorganic heat preservation material, the quality of cured tobacco leaves was good, and the quality of smoking was good; from 5 different adding thickness and proportion of processing, treatment effect of the inner wall thickness of 1.5 cm add 75% microcrystal inorganic heat preservation material was the best, the specific performance of the energy consumption was low, and the average coal consumption of 1 kg dry tobacco was 0.20 kg, and the coal saving rate was more than 14%; in terms of economic traits, the proportion of the first class tobacco leaf of cured tobacco increased by 4.6 percentage points, the average price increase of 2.0 yuan/kg(RMB) of tobacco; high quality of sensory evaluation, balanced chemical quality.%采用单因素试验设计,研究了微晶无机保温材料在提高烤房热能利用率、节约烤烟烘烤成本、提高烤后烟叶质量等方面的影响。结果表明:与对照相比,添加微晶无机保温材料烘烤成本较低,烤后烟叶等级质量好、评吸质量好;在5个不同添加厚度和比例的处理中,以内墙厚度1.5 cm 添加75%的微晶无机保温材料的处理效果最好,具体表现为能耗较低,每烘烤1 kg 干烟平均节煤0.20 kg,节煤率达14%以上;在经济性状方面,烤后烟叶的上等烟比例提高了4.6个百分点,烟叶均价平均提高2.0元/kg;感官评吸质量较高,化学品质均衡。

  5. COMBUSTION HEAT RELEASE RATE ANALYSIS OF C.I. ENGINE WITH SECONDARY CO-INJECTION OF DEE-H2O SOLUTION - A VIBRATIONAL APPROACH

    Directory of Open Access Journals (Sweden)

    Y. V. V. SATYANARAYANA MURTHY

    2015-08-01

    Full Text Available This paper discusses the combustion propensity of single cylinder direct injection engine fueled with palm kernel methyl ester (PKME, which is non- edible oil and a secondary co-injection of saturated Diethyl ether (DEE with water. DEE along with water is fumigated through a high pressure nozzle fitted to the inlet manifold of the engine and the flow rate of the secondary injection was electronically controlled. DEE is known to improve the cold starting problem in engines when used in straight diesel fuel. However, its application in emulsion form is little known. Experimental results show that for 5% DEE- H2O solution injection, occurrence of maximum net heat release rate is delayed due to controlled premixed combustion, which normally helped in better torque conversion when the piston is in accelerated mode. Vibration measurements in the frequency range of 900Hz to 1300Hz revealed that a new mode of combustion has taken place with different excitation frequencies.

  6. Efficacy of timed embryo transfer with fresh and frozen in vitro produced embryos to increase pregnancy rates in heat-stressed dairy cattle.

    Science.gov (United States)

    Ambrose, J D; Drost, M; Monson, R L; Rutledge, J J; Leibfried-Rutledge, M L; Thatcher, M J; Kassa, T; Binelli, M; Hansen, P J; Chenoweth, P J; Thatcher, W W

    1999-11-01

    Our objective was to determine whether pregnancy rates in heat-stressed dairy cattle could be enhanced by timed embryo transfer of fresh (nonfrozen) or frozen-thawed in vitro-derived embryos compared to timed insemination. Ovulation in Holstein cows was synchronized by a GnRH injection followed 7 d later by PGF2 alpha and a second treatment with GnRH 48 h later. Control cows (n = 129) were inseminated 16 h (d 0) after the second GnRH injection. On d 7, a fresh (n = 133) or frozen-thawed (n = 142) in vitro-derived embryo was transferred to cows assigned for timed embryo transfer after categorizing the corpus luteum by palpation per rectum as 3 (excellent), 2 (good or fair), 1 (poor), and 0 (nonpalpable). Response to the synchronization treatment, determined by plasma progesterone concentration (ng/ml) or = 2.0 on d 7, was 76.2%. Mean plasma progesterone concentration on d 7 increased as the quality of corpus luteum improved from category 0 to 3. Concentrations of progesterone in plasma were elevated (> or = 2.0 ng/ml) at 21 d in 64.7 (fresh embryo), 40.3 (frozen embryo), and 41.4 +/- 0.1% (timed insemination) of cows, respectively. Cows that received a fresh embryo had a greater pregnancy rate at 45 to 52 d than did cows that received a frozen-thawed embryo or timed insemination (14.3 > 4.8, 4.9 +/- 2.3%). Body condition (d 0) of cows influenced the pregnancy rate and plasma progesterone concentrations. In summary, timed embryo transfer with fresh in vitro-produced embryos in heat-stressed dairy cattle improved pregnancy rate relative to timed insemination.

  7. Effect of heat treatment on ethylene and CO2 emissions rates during papaya (Carica papaya L.) fruit ripening

    Science.gov (United States)

    da Silva, M. G.; Santos, E. O.; Sthel, M. S.; Cardoso, S. L.; Cavalli, A.; Monteiro, A. R.; de Oliveira, J. G.; Pereira, M. G.; Vargas, H.

    2003-01-01

    Ripening studies of nontreated and treated papaya (papaya L) are accomplished by monitoring the ethylene and CO2 emission rates of that climacteric fruit, to evaluate its shelf life. The treatments simulate the commercial Phitosanitarian process used to avoid the fly infestation. Ethylene emission was measured using a commercial CO2 laser driven photoacoustic setup and CO2, using a commercial gas analysis also based on the photothermal effect. The results show a marked change in ethylene and CO2 emission rate pattern for treated fruits when compared to the ones obtained for nontreated fruits and a displacement of the climacteric pick shown that the treatment causes a decrease of shelf life of fruit.

  8. Evidence for a twelfth large earthquake on the southern hayward fault in the past 1900 years

    Science.gov (United States)

    Lienkaemper, J.J.; Williams, P.L.; Guilderson, T.P.

    2010-01-01

    We present age and stratigraphic evidence for an additional paleoearthquake at the Tyson Lagoon site. The acquisition of 19 additional radiocarbon dates and the inclusion of this additional event has resolved a large age discrepancy in our earlier earthquake chronology. The age of event E10 was previously poorly constrained, thus increasing the uncertainty in the mean recurrence interval (RI), a critical factor in seismic hazard evaluation. Reinspection of many trench logs revealed substantial evidence suggesting that an additional earthquake occurred between E10 and E9 within unit u45. Strata in older u45 are faulted in the main fault zone and overlain by scarp colluviums in two locations.We conclude that an additional surfacerupturing event (E9.5) occurred between E9 and E10. Since 91 A.D. (??40 yr, 1??), 11 paleoearthquakes preceded the M 6:8 earthquake in 1868, yielding a mean RI of 161 ?? 65 yr (1??, standard deviation of recurrence intervals). However, the standard error of the mean (SEM) is well determined at ??10 yr. Since ~1300 A.D., the mean rate has increased slightly, but is indistinguishable from the overall rate within the uncertainties. Recurrence for the 12-event sequence seems fairly regular: the coefficient of variation is 0.40, and it yields a 30-yr earthquake probability of 29%. The apparent regularity in timing implied by this earthquake chronology lends support for the use of time-dependent renewal models rather than assuming a random process to forecast earthquakes, at least for the southern Hayward fault.

  9. Improvement of bio-oil yield and quality in co-pyrolysis of corncobs and high density polyethylene in a fixed bed reactor at low heating rate

    Science.gov (United States)

    Supramono, D.; Lusiani, S.

    2016-11-01

    Over the past few decades, interest in developing biomass-derived fuel has been increasing rapidly due to the decrease in fossil fuel reserves. Bio-oil produced by biomass pyrolysis however contains high oxygen compounds resulting in low calorific-value fuel and therefore requiring upgrading. In co-pyrolysis of the feed blend of plastics of High Density Polyethylene (HDPE) and biomass of com cob particles, at some compositions free radicals from plastic decomposition containing more hydrogen radicals are able to bond oxygen radicals originating from biomass to reduce oxygenate compounds in the bio-oil thus increasing bio-oil quality. This phenomenon is usually called synergetic effect. In addition to that, the pattern of heating of the feed blend in the pyrolysis reactor is predicted to affect biooil quality and yield. In a batch reactor, co-pyrolysis of corncobs and HDPE requires low heating rate to reach a peak temperature at temperature rise period followed by heating for some time at peak temperature called holding time at constant temperature period. No research has been carried out to investigate how long holding time is set in co-pyrolysis of plastic and biomass to obtain high yield of bio-oil. Holding time may affect either crosslinking of free radicals in gas phase, which increases char product, or secondary pyrolysis in the gas phase, which increases non-condensable gas in the gas phase of pyrolysis reactor, both of which reduce bio-oil yield. Therefore, holding time of co-pyrolysis affects the mass rate of bio-oil formation as the pyrolysis proceeds and quality of the bio-oil. In the present work, effects of holding time on the yield and quality of bio-oil have been investigated using horizontal fixed bed of the feed blends at heating rate of 5°C, peak temperature of 500°C and N2 flow rate of 700 ml/minute. Holding time was varied from 0 to 70 minutes with 10 minutes interval. To investigate the effects of holding time, the composition of HDPE in the

  10. Precipitation rates and atmospheric heat transport during the Cenomanian greenhouse warming in North America: Estimates from a stable isotope mass-balance model

    Science.gov (United States)

    Ufnar, David F.; Ludvigson, Greg A.; Gonzalez, L.; Grocke, D.R.

    2008-01-01

    correlate with a mean annual average heat loss of 48??W/m2 at 10??N paleolatitude (present, 8??W/m2 at 15??N). The increased precipitation flux and moisture surplus in the mid-latitudes corresponds to a mean average annual heat gain of 180??W/m2 at 50??N paleolatitude (present, 17??W/m2 at 50??N). The Cenomanian low-latitude moisture deficit is similar to that of the Albian, however the mid-latitude (40-60??N) precipitation flux values and precipitation rates are significantly higher (Albian: 2200??mm/yr at 45??N; Cenomanian: 3600??mm/yr at 45??N). Furthermore, the heat transferred to the atmosphere via latent heat of condensation was approximately 10.6?? that of the present at 50??N. The intensified hydrologic cycle of the mid-Cretaceous greenhouse warming may have played a significant role in the poleward transfer of heat and more equable global conditions. Paleoclimatological reconstructions from multiple time periods during the mid-Cretaceous will aid in a better understanding of the dynamics of the hydrologic cycle and latent heat flux during greenhouse world conditions.

  11. Rectal temperatures, respiratory rates, production, and reproduction performances of crossbred Girolando cows under heat stress in northeastern Brazil

    Science.gov (United States)

    da Costa, Antônio Nélson Lima; Feitosa, José Valmir; Montezuma, Péricles Afonso; de Souza, Priscila Teixeira; de Araújo, Airton Alencar

    2015-11-01

    This study compared the two breed groups of Girolando (½ Holstein ½ Gyr vs. ¾ Holstein ¼ Gyr) through analysis of the percentages (stressed or non-stressed cows) of rectal temperature (RT), respiratory rate (RR) and pregnancy rate (PR), and means of production and reproduction parameters to determine the group best suited to rearing in semiarid tropical climate. The experiment was conducted at the farm, in the municipality of Umirim, State of Ceará, Brazil. Two hundred and forty cows were used in a 2 × 2 factorial study; 120 of each group were kept under an intensive system during wet and dry seasons. The environmental parameters obtained were relative humidity (RH), air temperature (AT), and the temperature and humidity index (THI). Pregnancy diagnosis (PD) was determined by ultrasonography 30 days after artificial insemination (AI). The milk production of each cow was recorded with automated milkings in the farm. The variables were expressed as mean and standard error, evaluated by ANOVA at 5 % probability using the GLM procedure of SAS. Chi-square test at 5 % probability was applied to data of RT, RR, pregnancy rate (PR), and the number of AIs to obtain pregnancy. The majority of ½ Holstein cows showed mean values of RT and RR within the normal range in both periods and shifts. Most animals of the ¾ Holstein group exhibited the RR means above normal during the afternoon in the rainy and dry periods and RT means above normal during the afternoon in the dry period. After analyses, ½ Holstein crossbred cows are more capable of thermoregulating than ¾ Holstein cows under conditions of thermal stress, and the dry period was more impacting for bovine physiology with significant changes in physiological parameters, even for the first breed group. Knowledge of breed groups adapted to climatic conditions of northeastern Brazil can directly assist cattle farmers in selecting animals best adapted for forming herds.

  12. A summary of the Proceedings of the Twelfth International Symposium on the Neurobiology and Neuroendocrinology of Aging, Bregenz, Austria July 27-August 1, 2014.

    Science.gov (United States)

    Brown-Borg, Holly M; Borg, Kurt E

    2015-08-01

    A summary of the Twelfth International Symposium on the Neurobiology and Neuroendocrinology of Aging that was held July 27-August 1, 2014 in Bregenz, Austria, is presented. Fifteen of the speakers that presented at the conference submitted review papers covering the topic of their presentation as well as an overview of their respective fields and are included in this special issue. The abstracts from each poster presentation as well as seven of the speakers' abstracts are also included at the end of the preface to the special issue.

  13. Increasing ablation distance peripheral to the saphenofemoral junction may result in a diminished rate of endothermal heat-induced thrombosis.

    Science.gov (United States)

    Sadek, Mikel; Kabnick, Lowell S; Rockman, Caron B; Berland, Todd L; Zhou, Di; Chasin, Cara; Jacobowitz, Glenn R; Adelman, Mark A

    2013-07-01

    The treatment of venous insufficiency using endovenous laser ablation or radiofrequency ablation may result in endothermal heat-induced thrombosis (EHIT), a form of deep venous thrombosis. This study sought to assess whether increasing the ablation distance peripheral to the deep venous junction would result in a reduction in the incidence of EHIT II. This study was a retrospective review of a prospectively maintained database from April 2007 to December 2011. Consecutive patients undergoing great saphenous vein (GSV) or small saphenous vein (SSV) ablation were evaluated. Previous to February 2011, all venous ablations were performed 2 cm peripheral to the saphenofemoral or saphenopopliteal junction (group I). Subsequent to February 2011, ablations were performed greater than or equal to 2.5 cm peripheral to the respective deep system junction (group II). The primary outcome was the development of EHIT II or greater (ie, thrombus protruding into the deep venous system but comprising less than 50% of the deep vein lumen). Secondary outcomes included procedure-site complications such as thrombophlebitis and hematomas. χ(2) tests were performed for all discrete variables, and unpaired Student's t-tests were performed for all continuous variables. P result was significant (group I: 2.6% ± 0.9% vs group II: 2.8% ± 1.0%; P = .006). The incidence of EHIT II was 76 in group I and 13 in group II. This represented a trend toward diminished frequency in group II as compared with group I (group I: 2.3% vs group II: 1.3%; P = .066). There were no reported cases of EHIT III or IV in this patient cohort. Patients who developed an EHIT II in group I were treated using anticoagulation 54% of the time, and patients who developed an EHIT II in group II were treated using anticoagulation 100% of the time. This study suggests that changing the treatment distance from 2 cm to greater than or equal to 2.5 cm peripheral to the deep venous junction may result in a diminished

  14. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    Directory of Open Access Journals (Sweden)

    J. Hsu

    2017-07-01

    Full Text Available Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18–0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere.The Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM applications (RRTMG-SW. Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. We compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20–40 % depending on the solar zenith angles and occur throughout the atmosphere.Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components – wavelength

  15. A radiative transfer module for calculating photolysis rates and solar heating in climate models: Solar-J v7.5

    Science.gov (United States)

    Hsu, Juno; Prather, Michael J.; Cameron-Smith, Philip; Veidenbaum, Alex; Nicolau, Alex

    2017-07-01

    Solar-J is a comprehensive radiative transfer model for the solar spectrum that addresses the needs of both solar heating and photochemistry in Earth system models. Solar-J is a spectral extension of Cloud-J, a standard in many chemical models that calculates photolysis rates in the 0.18-0.8 µm region. The Cloud-J core consists of an eight-stream scattering, plane-parallel radiative transfer solver with corrections for sphericity. Cloud-J uses cloud quadrature to accurately average over correlated cloud layers. It uses the scattering phase function of aerosols and clouds expanded to eighth order and thus avoids isotropic-equivalent approximations prevalent in most solar heating codes. The spectral extension from 0.8 to 12 µm enables calculation of both scattered and absorbed sunlight and thus aerosol direct radiative effects and heating rates throughout the Earth's atmosphere.The Solar-J extension adopts the correlated-k gas absorption bins, primarily water vapor, from the shortwave Rapid Radiative Transfer Model for general circulation model (GCM) applications (RRTMG-SW). Solar-J successfully matches RRTMG-SW's tropospheric heating profile in a clear-sky, aerosol-free, tropical atmosphere. We compare both codes in cloudy atmospheres with a liquid-water stratus cloud and an ice-crystal cirrus cloud. For the stratus cloud, both models use the same physical properties, and we find a systematic low bias of about 3 % in planetary albedo across all solar zenith angles caused by RRTMG-SW's two-stream scattering. Discrepancies with the cirrus cloud using any of RRTMG-SW's three different parameterizations are as large as about 20-40 % depending on the solar zenith angles and occur throughout the atmosphere.Effectively, Solar-J has combined the best components of RRTMG-SW and Cloud-J to build a high-fidelity module for the scattering and absorption of sunlight in the Earth's atmosphere, for which the three major components - wavelength integration, scattering, and

  16. Dryout-type critical heat flux in vertical upward annular flow: effects of entrainment rate, initial entrained fraction and diameter

    Science.gov (United States)

    Wu, Zan; Wadekar, Vishwas; Wang, Chenglong; Sunden, Bengt

    2017-07-01

    This study aims to reveal the effects of liquid entrainment, initial entrained fraction and tube diameter on liquid film dryout in vertical upward annular flow for flow boiling. Entrainment and deposition rates of droplets were included in mass conservation equations to estimate the local liquid film mass flux in annular flow, and the critical vapor quality at dryout conditions. Different entrainment rate correlations were evaluated using flow boiling data of water and organic liquids including n-pentane, iso-octane and R134a. Effect of the initial entrained fraction (IEF) at the churn-to-annular flow transition was also investigated. A transitional Boiling number was proposed to separate the IEF-sensitive region at high Boiling numbers and the IEF-insensitive region at low Boiling numbers. Besides, the diameter effect on dryout vapor quality was studied. The dryout vapor quality increases with decreasing tube diameter. It needs to be pointed out that the dryout characteristics of submillimeter channels might be different because of different mechanisms of dryout, i.e., drying of liquid film underneath long vapor slugs and flow boiling instabilities.

  17. Energy drink use is associated with alcohol and substance use in eighth, tenth, and twelfth graders

    Directory of Open Access Journals (Sweden)

    Kathryn Polak

    2016-12-01

    Full Text Available The increasing prevalence of energy drink (ED use and its link with negative behaviors and adverse health outcomes has garnered much attention. Use of EDs combined with alcohol among college students has been of particular interest. It is unclear if these relationships develop in the context of college, or if similar associations exist in younger individuals. The present study examined associations between ED consumption patterns and other substance use in an adolescent, school-based sample. Participants were N = 3743 students attending 8th, 10th or 12th grade in a suburban central Virginia public school system who completed a prevention needs assessment survey in 2012. Chi-square analyses and logistic regressions were used to compare rates of alcohol, tobacco and other drug use across three ED use groups: moderate/heavy (12.6%, light (30.5%, and non-users (57%. Over 40% of the sample reported recent (past month ED use, with males more likely to report moderate/heavy ED use than females (14.0% and 11.1%, respectively; p = 0.02. After adjusting for gender and grade, ED use group predicted lifetime alcohol, tobacco and other drug use (all p < 0.001. Moderate/heavy ED users were most likely and ED non-users were least likely to report using each of the 13 substances in the survey, with light ED users intermediate to the other two groups. Moderate/heavy ED users were consistently most likely to report licit and illicit substance use. Additional research is needed to better understand which adolescents are at greatest risk for adverse health behaviors associated with ED use.

  18. Genetic Basis of Differential Heat Resistance between Two Species of Congeneric Freshwater Snails: Insights from Quantitative Proteomics and Base Substitution Rate Analysis.

    Science.gov (United States)

    Mu, Huawei; Sun, Jin; Fang, Ling; Luan, Tiangang; Williams, Gray A; Cheung, Siu Gin; Wong, Chris K C; Qiu, Jian-Wen

    2015-10-02

    We compared the heat tolerance, proteomic responses to heat stress, and adaptive sequence divergence in the invasive snail Pomacea canaliculata and its noninvasive congener Pomacea diffusa. The LT50 of P. canaliculata was significantly higher than that of P. diffusa. More than 3350 proteins were identified from the hepatopancreas of the snails exposed to acute and chronic thermal stress using iTRAQ-coupled mass spectrometry. Acute exposure (3 h exposure at 37 °C with 25 °C as control) resulted in similar numbers (27 in P. canaliculata and 23 in P. diffusa) of differentially expressed proteins in the two species. Chronic exposure (3 weeks of exposure at 35 °C with 25 °C as control) caused differential expression of more proteins (58 in P. canaliculata and 118 in P. diffusa), with many of them related to restoration of damaged molecules, ubiquitinating dysfunctional molecules, and utilization of energy reserves in both species; but only in P. diffusa was there a shift from carbohydrate to lipid catabolism. Analysis of orthologous genes encoding the differentially expressed proteins revealed two genes having clear evidence of positive selection (Ka/Ks > 1) and seven candidates for more detailed analysis of positive selection (Ka/Ks between 0.5 and 1). These nine genes are related to energy metabolism, cellular oxidative homeostasis, signaling, and binding processes. Overall, the proteomic and base substitution rate analyses indicate genetic basis of differential resistance to heat stress between the two species, and such differences could affect their further range expansion in a warming climate.

  19. Report on the results of the twelfth medical examination of atomic bomb survivors residing in North America

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yasuji [Hiroshima Prefectural Medical Association (Japan); Ohama, Koso; Fujiwara, Saeko (and others)

    2000-06-01

    The twelfth medical examination of atomic bomb survivors residing in North America, was conducted in San Francisco and Seattle from May 20 through June 2 1999, and in Los Angeles and Hawaii from June 9 through 23 1999, The examination included an interview, measurement of height, weight, and blood pressure, an ECG, urine and stool tests, blood tests, a physical examination, examination of the breast, thyroid, and rectum by a surgeon, and screening for uterine cancer and a gynecological interview and examination by an obstetrician and gynecologist. The total confirmed number of A-bomb survivors residing in North America as of the end of June 1999 was 1076. Of the 1062 survivors that remained after excluding the 14 subjects whose survey was incomplete, 279 males and 654 females had been exposed in Hiroshima, and 10 males and 119 females in Nagasaki. The peak age at the time of exposure in both sexes was 15-19 years, followed by 10-14 years. The number of survivors exposed <2000 m from the hypocenter was 236, accounting for 21.9% of the total. The confirmed number of survivors exposed in utero was 26. The survivors' age (mean {+-}S.D.) was: 69.0{+-}8.69 years; males, 68.4{+-}80.5 years; females, 69.2{+-}8.91 years. A total of 414 survivors were examined (male 129; female 285; mean age 68.0 years). Approximately 80% of the examinees had experienced at least one general symptom. Many still complain of symptoms that suggest possible posttraumatic stress disorder as a result of exposure to the A-bomb. It will be necessary to consider providing mental health care by psychiatrists beginning with the next examination. The prevalence of life-style diseases has been gradually increased with age. A previous history of cancer was found in 9.2% of the examinees. The most prevalent was of breast cancer, followed by malignant tumors of the colon, rectum, uterus, brain, stomach, and thyroid. The need for cancer screening and promotion of life-style education was keenly felt. (K.H.)

  20. Development and experimental evaluation of a thermography measurement system for real-time monitoring of comfort and heat rate exchange in the built environment

    Science.gov (United States)

    Revel, G. M.; Sabbatini, E.; Arnesano, M.

    2012-03-01

    A measurement system based on infrared (IR) thermovision technique (ITT) is developed for real-time estimation of room thermal variations and comfort conditions in office-type environment as a part of a feasibility study in the EU FP7 project ‘INTUBE’. An IR camera installed on the ceiling allows thermal image acquisition and post-processing is performed to derive mean surface temperatures, number of occupants and presence of other heat sources (e.g. computer) through detecting algorithms. A lumped parameter model of the room, developed in the Matlab/Simulink environment, receives as input the information extracted from image processing to compute room exchanged heat rate, air temperature and thermal comfort (PMV). The aim is to provide in real time the room thermal balance and comfort information for energy-saving purposes in an improved way with respect to traditional thermostats. Instantaneous information can be displayed for the users or eventually used for automatic HVAC control. The system is based on custom adaptation of a surveillance low-cost IR system with dedicated radiometric calibration. Experimental results show average absolute discrepancies in the order of 0.4 °C between calculated and measured air temperature during a time period of a day. A sensitivity analysis is performed in order to identify main uncertainty sources.

  1. Coupled Chemical and Thermal Processes During Contact Metamorphism: Constraining Rates and Duration with Time-Dependent 3-D Heat and Mass Transport Modeling of Fluid-Rock Systems

    Science.gov (United States)

    Dutrow, B. L.; Henry, D.; Gable, C. W.; Heydari, E.; Travis, B. J.

    2016-12-01

    Hydrothermal, metamorphic and metasomatic rocks develop through a complex set of coupled thermal, chemical and mechanical processes that contain non-linear feedbacks. The integrated outcome results in a mineral assemblage with a specific texture that records the rates, magnitude and duration of the controlling processes. However, it is often difficult to extract this coupled information from the rock record due to the competing and time-integrated nature of the final product. A particularly problematic case arises when advective metasomatism accompanies thermal energy transport. Advective transport of reactive components by thermally driven flowing fluids can dramatically alter the original bulk rock chemistry. In some instances, these chemical transformations are slow but in others, these alterations can occur over short time scales (yrs). To facilitate investigations of coupled, complex systems and to constrain the rates, duration and relative importance of governing processes during a thermal event, high-resolution 3-D time dependent computational modeling is used. An example of the integrated effects of thermal and chemical transport is found in subsurface Louisiana. Here, an 11m alkali igneous dike intruded Late Jurassic sandy limestones transforming these into new mineral assemblages rich in alkali, alkaline earth elements and F; hydrogrossular, diopside, pectolite (pct), apophyllite, fluorite, and feldspars. Increased temperatures (Ts) and significant mass transport of components from the dike into the host rocks are required. A series of coupled heat and mass transport calculations constrain the rates and duration of the thermal pulse and provide insights into the time-scale of mass transport within this system. For example, calculations incorporating silica transport indicate that at the pct zone (1.5m), thermal conditions remained above 150oC for 2.8 yrs assuming anisotropic permeability (K) and 4.2 yrs (layered K) reaching Tmax at 0.36 (aniso) or 0.53 yr

  2. Thermoluminescence glow curve for UV induced ZrO2:Ti phosphor with variable concentration of dopant and various heating rate

    Directory of Open Access Journals (Sweden)

    Neha Tiwari

    2014-10-01

    Full Text Available The present paper reports the synthesis and characterization of Ti doped ZrO2 nanophosphors. The effects of variable concentration of titanium on thermoluminescence (TL behaviour are studied. The samples were prepared by combustion a synthesis technique which is suitable for less time taking techniques also for large scale production for nano phosphors. The starting material used for sample preparation are Zr(NO33 and Ti(NO33 and urea used as a fuel. The prepared sample was characterized by X-ray diffraction technique (XRD with variable concentration of Ti (0.05–0.5 mol% there is no any phase change found with increase the concentration of Ti. Sample shows cubic structure and the particle size calculated by Scherer's formula. The surface morphology of prepared phosphor was determined by field emission gun scanning electron microscopy (FEGSEM technique for optimized concentration of dopant. The good connectivity with grains and the semi-sphere like structure was found by FEGSEM. The functional group analysis was determined by Fourier transform infrared (FTIR spectroscopic techniques. The prepared phosphor examined by thermoluminescence technique. For recording TL glow curve every time 2 mg phosphor was irradiated by UV 254 nm source and fixed the heating rate at 5 °C s−1. Sample shows well resolved peak at 167 °C with a shoulder peak at 376 °C. The higher temperature peak shows the well stability and less fading in prepared phosphor. Also the effect of Ti concentration at fixed UV exposure time was studied. The effect of UV exposure time and dose versus intensity plot was studied. Sample shows linear response with dose and broaden peak with high temperature shows the more stability and less fading in TL glow curve. The linear dose response, high stability and less fading phenomenon shows the sample may be useful for thermoluminescence dosimetry application. Trapping parameters are calculated for every recorded glow curve. The

  3. Characterization of Free Radicals By Electron Spin Resonance Spectroscopy in Biochars from Pyrolysis at High Heating Rates and at High Temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Jensen, Anker Degn; Larsen Andresen, Mogens

    Understanding fast pyrolysis of biomass-derived materials is an important step in optimization of combustion processes. Similar to coal combustion, the fuel burn out is known to be influenced by the yield and reactivity of chars, produced during pyrolysis. The rapid heating of small biomass...... particles and the short residence time at high temperatures minimize the char yield and increase char reactivity. The differences in chemical composition of organic and inorganic matter between wood and herbaceous biomass affect the operational flexibility of power plants, and increase the complexity...... of mathematical models that can predict yields, composition and rates of product (char, tar, light gases) formation from fast pyrolysis. The modeling of cross-linking and polymerization reactions in biomass pyrolysis includes the formation of free radicals and their disappearance. Knowledge about these radical...

  4. Application of information statistical theory to the description of the effect of heat conduction on the chemical reaction rate in gases

    Energy Technology Data Exchange (ETDEWEB)

    Fort, J. [Seccio de Fisica, Escola Politecnica Superior, Universitat de Girona, Girona (Spain); Cukrowski, A.S. [Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw (Poland)]|[Faculty of Mathematical and Natural Sciences, Institute of Chemisty, Pedagogical University, Kielce (Poland)

    1998-06-01

    The effect of the heat flux on the rate of chemical reaction in dilute gases is shown to be important for reactions characterized by high activation energies and in the presence of very large temperature gradients. This effect, obtained from the second-order terms in the distribution function (similar to those obtained in the Burnett approximation to the solution of the Boltzmann equation), is derived on the basis of information theory. It is shown that the analytical results describing the effect are simpler if the kinetic definition for the nonequilibrium temperature is introduced than if the thermodynamic definition is introduced. The numerical results are nearly the same for both definitions. (author) 35 refs, 2 figs

  5. The Effect of a Rapid Heating Rate, Mechanical Vibration and Surfactant Chemistry on the Structure–Property Relationships of Epoxy/Clay Nanocomposites

    Science.gov (United States)

    Nuhiji, Betime; Attard, Darren; Thorogood, Gordon; Hanley, Tracey; Magniez, Kevin; Bungur, Jenny; Fox, Bronwyn

    2013-01-01

    The role of processing conditions and intercalant chemistry in montmorillonite clays on the dispersion, morphology and mechanical properties of two epoxy/clay nanocomposite systems was investigated in this paper. This work highlights the importance of employing complementary techniques (X-ray diffraction, small angle X-ray scattering, optical microscopy and transmission electron microscopy) to correlate nanomorphology to macroscale properties. Materials were prepared using an out of autoclave manufacturing process equipped to generate rapid heating rates and mechanical vibration. The results suggested that the quaternary ammonium surfactant on C30B clay reacted with the epoxy during cure, while the primary ammonium surfactant (I.30E) catalysed the polymerisation reaction. These effects led to important differences in nanocomposite clay morphologies. The use of mechanical vibration at 4 Hz prior to matrix gelation was found to facilitate clay dispersion and to reduce the area fraction of I.30E clay agglomerates in addition to increasing flexural strength by over 40%. PMID:28811457

  6. The Effect of a Rapid Heating Rate, Mechanical Vibration and Surfactant Chemistry on the Structure–Property Relationships of Epoxy/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Kevin Magniez

    2013-08-01

    Full Text Available The role of processing conditions and intercalant chemistry in montmorillonite clays on the dispersion, morphology and mechanical properties of two epoxy/clay nanocomposite systems was investigated in this paper. This work highlights the importance of employing complementary techniques (X-ray diffraction, small angle X-ray scattering, optical microscopy and transmission electron microscopy to correlate nanomorphology to macroscale properties. Materials were prepared using an out of autoclave manufacturing process equipped to generate rapid heating rates and mechanical vibration. The results suggested that the quaternary ammonium surfactant on C30B clay reacted with the epoxy during cure, while the primary ammonium surfactant (I.30E catalysed the polymerisation reaction. These effects led to important differences in nanocomposite clay morphologies. The use of mechanical vibration at 4 Hz prior to matrix gelation was found to facilitate clay dispersion and to reduce the area fraction of I.30E clay agglomerates in addition to increasing flexural strength by over 40%.

  7. HMI Data Driven Magnetohydrodynamic Model Predicted Active Region Photospheric Heating Rates: Their Scale Invariant, Flare Like Power Law Distributions, and Their Possible Association With Flares

    Science.gov (United States)

    Goodman, Michael L.; Kwan, Chiman; Ayhan, Bulent; Shang, Eric L.

    2017-01-01

    A data driven, near photospheric, 3 D, non-force free magnetohydrodynamic model predicts time series of the complete current density, and the resistive heating rate Q at the photosphere in neutral line regions (NLRs) of 14 active regions (ARs). The model is driven by time series of the magnetic field B observed by the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory (SDO) satellite. Spurious Doppler periods due to SDO orbital motion are filtered out of the time series for B in every AR pixel. Errors in B due to these periods can be significant. The number of occurrences N(q) of values of Q > or = q for each AR time series is found to be a scale invariant power law distribution, N(Q) / Q-s, above an AR dependent threshold value of Q, where 0.3952 or = E obeys the same type of distribution, N(E) / E-S, above an AR dependent threshold value of E, with 0.38 < or approx. S < or approx. 0.60, also with little variation among ARs. Within error margins the ranges of s and S are nearly identical. This strong similarity between N(Q) and N(E) suggests a fundamental connection between the process that drives coronal flares and the process that drives photospheric NLR heating rates in ARs. In addition, results suggest it is plausible that spikes in Q, several orders of magnitude above background values, are correlated with times of the subsequent occurrence of M or X flares.

  8. Effect of Metallothionein on Cell Cycle, Apoptosis Rate and Subsets Distribution of Lymphocytes in Peripheral Blood of Dairy Cattle under Heat Stress

    Institute of Scientific and Technical Information of China (English)

    Jiajie LUO; Jun FANG; Lili LI; Bin ZHANG; LiZhuan WU; Zijun LI; Ying PENG; JueXin FAN; XinYi LAN; JinShun ZHAN

    2013-01-01

    [Objective] This study aimed to research the effect of metal othionein on cellcycle, apoptosis rate and subsets distribution of lymphocytes in peripheral blood of dairy cows under heat stress, so as to perfect the regulative mechanism re-searches of MT to anti-heat stress. [Method] Twenty lactating Chinese Holstein cows were randomly divided into four groups (A, B, C and D), and injected with 0, 4.0, 8.0 and 12.0 mg Zn-metal othionein, respectively by intravenous route. Blood sam-ples were col ected at 1st, 16th, 31st, 46th and 61st day, and the dynamic changes of cellcycle, apoptosis rate and subsets distribution of lymphocytes were determined. [Result] The apoptosis rate of cells in group B and C was lower than those in group A by 26.63% (P>0.05) and 24.84% (P>0.05) respectively. The number of cells in the G0/G1 phage in trial groups was increased and the number of cells in the S and G2/M phages tended to decrease, but there were no significant differences (P>0.05). The number of CD3+ T cellin three trial groups was greater than those in group A by 7.02% (P>0.05), 5.45% (P>0.05) and 3.85% (P>0.05) respectively, while the number of CD4+ T cellin trial groups was higher than those in control group by 31.04% (P<0.05), 35.68% (P<0.05) and 39.34% (P<0.05) respectively. The number of CD8+ T celland the levels of CD4+/CD8+ in trial groups were increased observ-ably, but significant difference (P<0.05) was observed in the levels of CD4+/CD8+between groups A and C only. It demonstrated that exogenous Zn-metal othionein can decrease apoptosis rate, improve cellcycle and regulate subsets distribution of lymphocytes in dairy cattle in a dose-dependent manner. [Conclusion] This study wil provide scientific basis for safe utilization of MT in dairy industry.

  9. Introduction to heat transfer

    CERN Document Server

    SUNDÉN, B

    2012-01-01

    Presenting the basic mechanisms for transfer of heat, Introduction to Heat Transfer gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers.

  10. Experimental research on heat transfer of pulsating heat pipe

    Institute of Scientific and Technical Information of China (English)

    LI Jia; Yan Li

    2008-01-01

    Experimental research was conducted to understand heat transfer characteristic of pulsating heat pipe in this paper,and the PHP is made of high quality glass capillary tube. Under different fill ratio, heat transfer rate and many other influence factors, the flow patterns were observed in the start-up, transition and stable stage. The effects of heating position on heat transfer were discussed. The experimental results indicate that no annular flow appears in top heating condition. Under different fill ratios and heat transfer rate, the flow pattern in PHP is transferred from bulk flow to semi-annular flow and annular flow, and the performance of heat transfer is improved for down heating case. The experimental results indicate that the total heat resistant of PHP is increased with fill ratio, and heat transfer rate achieves optimum at filling rate 50%. But for pulsating heat pipe with changing diameters the thermal resistance is higher than that with uniform diameters.

  11. Modelling the effect of sub(lethal) heat treatment of Bacillus subtilis spores on germination rate and outgrowth to exponentially growing vegetative cells

    NARCIS (Netherlands)

    Smelt, J.P.P.M.; Bos, A.P.; Kort, R.; Brul, S.

    2008-01-01

    Spores of Bacillus subtilis were subjected to relatively mild heat treatments in distilled water and properties of these spores were studied. These spores had lost all or part of their dipicolinic acid (DPA) depending on the severity of the heat treatment. Even after relatively mild heat treatments

  12. The investigation of nucleation rate and Johnson–Mehl–Avrami model of Pt–Pd alloy using molecular dynamics simulation during heat treatment processes

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Fatih Ahmet, E-mail: facelik@beu.edu.tr

    2015-05-25

    Highlights: • The Avrami exponent increases with increasing annealing temperature. • Recrystallization occurrence is most likely at low temperatures. • Heat of fusion and critical nucleus radius are evaluated from the MD calculations. - Abstract: In this work, molecular dynamics simulation is carried out to investigate the crystallization kinetics at low cooling rate during solidification and at different annealing temperature from amorphous phase during annealing of Pt–Pd (Pt{sub 50}–Pd{sub 50}) model alloy system. The interfacial free energies, critical nucleus radius, total free energy from high temperatures to low temperatures during solidification of alloy system are also determined by molecular dynamics. At the same time, in order to define the nucleation rate, it is suggested a model based on nucleation theory. The local atomic bonded pairs and short range order properties in the model alloy have been analyzed using Honeycutt–Andersen (HA) method. The kinetic of the crystallization is described by Johnson, Mehl and Avrami (JMA) model, which has been analyzed with MD method by using the crystalline-type bonded pairs during annealing process. The results demonstrated that the crystal kinetics is very important to understand the process of homogenous nucleation formation and also, the results are consistent with the classical nucleation theory.

  13. How Dead are Dead Galaxies? Mid-Infrared Fluxes of Quiescent Galaxies at Redshift 0.3Star Formation Rates and Dust Heating

    Science.gov (United States)

    Fumagalli, Mattia; Labbe, Ivo; Patel, Shannon G.; Franx, Marijn; vanDokkum, Pieter; Brammer, Gabriel; DaCunha, Elisabete; FoersterSchreiber, Natascha M.; Kriek, Mariska; Quadri, Ryan; Rix, Hans-Walter; Wake, David; Whitaker, Katherine E.; Lundgren, Britt; Marchesini, Danilo; Maseda, Michael; Momcheva, Ivelina; Nelson, Erica; Pacifici, Camilla; Skelton, Rosalind E.

    2013-01-01

    We investigate star formation rates of quiescent galaxies at high redshift (0.3 star formation rates for quiescent galaxies (sSFR approx. 10(exp -12)/yr. However, SED fitting can miss star formation if it is hidden behind high dust obscuration and ionizing radiation is re-emitted in the mid-infrared. It is therefore fundamental to measure the dust-obscured SFRs with a mid-IR indicator. We stack the MIPS-24 micron images of quiescent objects in five redshift bins centered on z = 0.5, 0.9, 1.2, 1.7, 2.2 and perform aperture photometry. Including direct 24 micron detections, we find sSFR approx. 10(exp -11.9) × (1 + z)(sup 4)/yr. These values are higher than those indicated by SED fitting, but at each redshift they are 20-40 times lower than those of typical star forming galaxies. The true SFRs of quiescent galaxies might be even lower, as we show that the mid-IR fluxes can be due to processes unrelated to ongoing star formation, such as cirrus dust heated by old stellar populations and circumstellar dust. Our measurements show that star formation quenching is very efficient at every redshift. The measured SFR values are at z > 1.5 marginally consistent with the ones expected from gas recycling (assuming that mass loss from evolved stars refuels star formation) and well above that at lower redshifts.

  14. A study of the heat treatment time, temperature and ramp rate on the transport current properties and Bi-2223 grain growth in (Bi,Pb)2223/Ag superconducting tapes

    CERN Document Server

    Young, E A

    2002-01-01

    The Bi-2223 phase formation in (Bi,Pb)2223/Ag tapes is known to be via a Pb rich liquid phase, the control of the wetting properties and the phase volume of liquid phase in the early hours of sintering can substantially improve the transport current of the final sintered tape. The phase volume of liquid phase, characterised by the formation of the Bi sub 2 (Sr sub 1 sub . sub 6 Ca sub 0 sub . sub 4)CuO sub 6 , (Bi-2201), phase, was observed to depend on the heat treatment temperature and atmosphere. The volume of secondary phases, (Cu sub 2 O, Cu-free phase, and Bi sub 2 (Sr sub 1 sub . sub 6 Ca sub 0 sub . sub 4)CuO sub 6), in the sintered Bi-2223 microstructure is shown to be sensitive to the sintering heating rate, and this is thought to be related to the wetting properties of the liquid phase. For an optimum transport critical current, (77K, self field), the heat treatment temperature and the heating rate are inter-dependent parameters, the heating rate only increasing the transport current of tapes heat ...

  15. Relationships Between Base-Catalyzed Hydrolysis Rates or Glutathione Reactivity for Acrylates and Methacrylates and Their NMR Spectra or Heat of Formation

    Directory of Open Access Journals (Sweden)

    Yoshinori Kadoma

    2012-05-01

    Full Text Available The NMR chemical shift, i.e., the π-electron density of the double bond, of acrylates and methacrylates is related to the reactivity of their monomers. We investigated quantitative structure-property relationships (QSPRs between the base-catalyzed hydrolysis rate constants (k1 or the rate constant with glutathione (GSH (log kGSH for acrylates and methacrylates and the 13C NMR chemical shifts of their α,β-unsaturated carbonyl groups (δCα and δCβ or heat of formation (Hf calculated by the semi-empirical MO method. Reported data for the independent variables were employed. A significant linear relationship between k1 and δCβ, but not δCα, was obtained for methacrylates (r2 = 0.93, but not for acrylates. Also, a significant relationship between k1 and Hf was obtained for both acrylates and methacrylates (r2 = 0.89. By contrast, log kGSH for acrylates and methacrylates was linearly related to their δCβ (r2 = 0.99, but not to Hf. These findings indicate that the 13C NMR chemical shifts and calculated Hf values for acrylates and methacrylates could be valuable for estimating the hydrolysis rate constants and GSH reactivity of these compounds. Also, these data for monomers may be an important tool for examining mechanisms of reactivity.

  16. The circulation pattern and day-night heat transport in the atmosphere of a synchronously rotating aquaplanet: Dependence on planetary rotation rate

    Science.gov (United States)

    Noda, S.; Ishiwatari, M.; Nakajima, K.; Takahashi, Y. O.; Takehiro, S.; Onishi, M.; Hashimoto, G. L.; Kuramoto, K.; Hayashi, Y.-Y.

    2017-01-01

    In order to investigate a possible variety of atmospheric states realized on a synchronously rotating aquaplanet, an experiment studying the impact of planetary rotation rate is performed using an atmospheric general circulation model (GCM) with simplified hydrological and radiative processes. The entire planetary surface is covered with a swamp ocean. The value of planetary rotation rate is varied from zero to the Earth's, while other parameters such as planetary radius, mean molecular weight and total mass of atmospheric dry components, and solar constant are set to the present Earth's values. The integration results show that the atmosphere reaches statistically equilibrium states for all runs; none of the calculated cases exemplifies the runaway greenhouse state. The circulation patterns obtained are classified into four types: Type-I characterized by the dominance of a day-night thermally direct circulation, Type-II characterized by a zonal wave number one resonant Rossby wave over a meridionally broad westerly jet on the equator, Type-III characterized by a long time scale north-south asymmetric variation, and Type-IV characterized by a pair of mid-latitude westerly jets. With the increase of planetary rotation rate, the circulation evolves from Type-I to Type-II and then to Type-III gradually and smoothly, whereas the change from Type-III to Type-IV is abrupt and discontinuous. Over a finite range of planetary rotation rate, both Types-III and -IV emerge as statistically steady states, constituting multiple equilibria. In spite of the substantial changes in circulation, the net energy transport from the day side to the night side remains almost insensitive to planetary rotation rate, although the partition into dry static energy and latent heat energy transports changes. The reason for this notable insensitivity is that the outgoing longwave radiation over the broad area of the day side is constrained by the radiation limit of a moist atmosphere, so that the

  17. Forecast and Analysis of the Main Indicators for the Development of Ocean Fishery in China during the Twelfth Five-Year Plan Period

    Institute of Scientific and Technical Information of China (English)

    Xianghong; LIN; Zhankun; WANG; Weiling; SONG; Congchun; XU

    2013-01-01

    The ocean fishery is an important part of the marine economy and an important source of human food.The leaders at all levels attach great importance to the development and utilization of ocean fishery resources.Using the regression analysis method,we forecast the main indicators for the development of ocean fishery during the Twelfth Five-Year Plan period.Through the study,it is found that in 2015,the value added of ocean fishery in China is expected to exceed 360 billion yuan,and the output of marine products will exceed 30 million tons.The marine products make stable contribution to the marine economy and the residents’nutrient composition,conducive to maintaining the stable supply of the market and meeting the residents’daily needs for marine products.

  18. The influence of plasma horizontal position on the neutron rate and flux of neutral atoms in injection heating experiment on the TUMAN-3M tokamak

    Science.gov (United States)

    Kornev, V. A.; Chernyshev, F. V.; Melnik, A. D.; Askinazi, L. G.; Wagner, F.; Vildjunas, M. I.; Zhubr, N. A.; Krikunov, S. V.; Lebedev, S. V.; Razumenko, D. V.; Tukachinsky, A. S.

    2013-11-01

    Horizontal displacement of plasma along the major radius has been found to significantly influence the fluxes of 2.45 MeV DD neutrons and high-energy charge-exchange atoms from neutral beam injection (NBI) heated plasma of the TUMAN-3M tokamak. An inward shift by Δ R = 1 cm causes 1.2-fold increase in the neutron flux and 1.9-fold increase in the charge-exchange atom flux. The observed increase in the neutron flux is attributed to joint action of several factors-in particular, improved high-energy ion capture and confinement and, probably, decreased impurity inflow from the walls, which leads to an increase in the density of target ions. A considerable increase in the flux of charge-exchange neutrals in inward-shifted plasma is due to the increased number of captured high-energy ions and, to some extent, the increased density of the neutral target. As a result of the increase in the content of high-energy ions, the central ion temperature T i (0) increased from 250 to 350 eV. The dependence of the neutron rate on major radius R 0 should be taken into account when designing compact tokamak-based neutron sources.

  19. Changes in swelling properties and moisture uptake rate of oil-heat-treated poplar (Populus x euramericana cv. Pannónia wood

    Directory of Open Access Journals (Sweden)

    Miklós Bak

    2012-11-01

    Full Text Available In this work, the effect of oil heat treatment (OHT on the swelling properties and changes in the rate of moisture uptake of poplar wood (Populus × euramericana cv. Pannónia were investigated. Eighteen different treatments (combinations of three vegetable oils, two temperatures, and three durations were studied. The results showed that OHT decreases the equilibrium moisture content (EMC and the swelling of poplar wood. The degree of swelling and the EMC are influenced by both the duration and temperature of treatment. With an increase in duration and temperature, the EMC decreased. Consequently, the anti-swelling efficiency (ASE increased. OHT wood adsorbs less moisture than natural wood, but it reaches a maximum – EMC at the momentary climate – at the same time under all the investigated treatments. The moisture uptake is fastest in the beginning and thereafter it slows significantly. Decreasing the moisture uptake by OHT wood is due to the decreasing of its water storage capacity.

  20. Effect of the cooling rate during heat treatment and hot isostatic pressing on the microstructure of a SX Ni-superalloy

    Directory of Open Access Journals (Sweden)

    Lopez-Galilea Inmaculada

    2014-01-01

    Full Text Available Single crystal Ni-based gas turbine blades show a combination of large casting pores and pores from the homogenization heat treatment. Both kinds of pores can only be reduced by HIP; however, HIP not only reduces porosity but also affects the size, number and morphology of γ′ particles. From the HIP parameters, pressure, temperature, holding time and cooling speed, the main effect on both, the porosity and the γ/γ′ microstructure is due to temperature and cooling rate. HIP temperatures above the γ′ solvus temperature allow the fastest and most effective reduction of the porosity, because only the soft γ phase is present. The recent and novel possibility of cooling the samples from the maximum HIP temperature with a fast cooling of about 200 K/min, results in a fine and homogeneous distribution of γ′ particles, which requires no additional solution annealing treatment to dissolve the developed γ′ particles during the extremely short cooling time. Therefore, the application of HIP at super γ′ solvus temperature followed by fast cooling on homogenized samples seems to have the most promising results: no porosity and fine γ/γ′ microstructure.

  1. [Searching Radiation Countermeasures using the Model of Prolonged Irradiation of Mice with Low Dose Rate and Evaluation of Their Influence on Heat Shock Protein Genes Expression].

    Science.gov (United States)

    Rozhdestvensky, L M; Mikhailov, V F; Schlyakova, T G; Shagirova, J M; Shchegoleva, R A; Raeva, N F; Lisina, N I; Shulenina, L V; Zorin, V V; Pchelka, A V; Trubitsina, K Y

    2015-01-01

    Different radiomodificators (cytokine betaleukine, antioxidant phenoxan, antigipoksant limontar and nucleoside riboxin) were investigated on mice for evaluating their radiation protective capacity against prolonged (21 h) exposure at a dose of 12.6 Gy at a low dose rate of 10 mGy/min. Bone marrow cellularity and endogenic CFUs were used as evaluation criteria 9 days after exposure. Simultaneously, expression of the heat shock proteins of 25, 70 and 90 kDa in unexposed mice bone marrow was studied 2, 24 and 48 h after injections. Betaleukine only had a positive significant effect in both tests in the variants of 50 mcg/kg and 3 mcg/kg when administered 2 h and 22 h before exposure, correspondingly. Effects of betaleukine HSPs on expression were both stimulating and inhibiting, that was in contradiction with a constant positive effect in 5 experiments on exposed mice for each betaleukine variant. It argues against the vital role of HSPs in the betaleukine antiradiation effect. In 2 experiments with high temperatures betaleukine administered at a dose of 50 mcg/kg evoked a very high HSP-70 gene expression after 24 h, and mice exposed to irradiation at that time in a parallel experiment showed an increased radiation effect. It corresponds to the idea that HSPs serve a stress indicator.

  2. TG-FTIR characterization of coal and biomass single fuels and blends under slow heating rate conditions: Partitioning of the fuel-bound nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Di Nola, G.; de Jong, W.; Spliethoff, H. [Energy Technology Section, Process and Energy Department, Faculty 3me, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands)

    2010-01-15

    The devolatilization behavior of a bituminous coal and different biomass fuels currently applied in the Dutch power sector for co-firing was experimentally investigated. The volatile composition during single fuel pyrolysis as well as during co-pyrolysis was studied using TG-FTIR characterization with the focus on the release patterns and quantitative analysis of the gaseous bound nitrogen species. It was shown that all investigated biomass fuels present more or less similar pyrolysis behavior, with a maximum weight loss between 300 and 380 C. Woody and agricultural biomass materials show higher devolatilization rates than animal waste. When comparing different fuels, the percentage of fuel-bound nitrogen converted to volatile bound-N species (NH{sub 3}, HCN, HNCO) does not correlate with the initial fuel-N content. Biomass pyrolysis resulted in higher volatile-N yields than coal, which potentially indicates that NO{sub x} control during co-firing might be favored. No significant interactions occurred during the pyrolysis of coal/biomass blends at conditions typical of TG analysis (slow heating rate). Evolved gas analysis of volatile species confirmed the absence of mutual interactions during woody biomass co-pyrolysis. However, non-additive behavior of selected gas species was found during slaughter and poultry litter co-pyrolysis. Higher CH{sub 4} yields between 450 and 750 C and higher ammonia and CO yields between 550 and 900 C were measured. Such a result is likely to be attributed to catalytic effects of alkali and alkaline earth metals present in high quantity in animal waste ash. The fact that the co-pyrolysis of woody and agricultural biomass is well modeled by simple addition of the individual behavior of its components permits to predict the mixture's behavior based on experimental data available for single fuels. On the other hand, animal waste co-pyrolysis presented in some cases synergistic effects in gas products although additive behavior

  3. An Experimental Investigation of Ice-melting and heat transfer rates from submerged warm water jets upward impinging into ice-blocks as analogous for water-filled cavities formed during subglacial eruptions.

    Science.gov (United States)

    Jamshidnia, Hamidreza; Gudmundsson, Magnus Tumi

    2016-11-01

    Rates of energy transfer in water-filled cavities formed under glaciers by geothermal and volcanic activity are investigated by conducting experiments in which hot water jets (10°- 90°C) impinging into an ice block for jet Reynolds numbers in turbulent regime of 10000 -70000. It is found that heat flux is linearly dependent on jet flow temperature. Water jet melts a cavity into an ice block. Cavities had steep to vertical sides with a doming roof. Some of ice blocks used had trapped air bubbles. In these cases that melting of the ice could have led to trapping of air at the top of cavity, partially insulating the roof from hot water jet. The overall heat transfer rate in cavity formation varied with jet temperature from <100 kW m-2 to 900 kW m-2 while melting rates in the vertical direction yield heat transfer rates of 200-1200 kW m-2. Experimental heat transfer rates can be compared to data on subglacial melting observed for ice cauldrons in Iceland. For lowest temperatures the numbers are comparable to those for geothermal water in cool, subglacial water bodies and above subglacial flowpaths of jökulhlaups. Highest experimental rates for 80-90°C jets are 3-10 times less than inferred from observations of recent subglacial eruptions (2000-4000 kW m-2) . This can indicate that single phase liquid water convection alone may not be sufficient to explain the rates seen in recent subglacial eruptions, suggesting that forced 2 or 3 phase convection can be common.

  4. Rating of an air-to-air tube-type heat exchanger in a piglet house; Energetische Untersuchung eines Luft-Luft-Rohrwaermetauschers in einem Ferkelaufzuchtstall

    Energy Technology Data Exchange (ETDEWEB)

    Roesmann, Peter; Boge, Henrich; Buescher, Wolfgang [Bonn Univ. (Germany). Abt. ' ' Verfahrenstechnik in der Tierischen Erzeugung' '

    2011-07-01

    Due to the high temperature requirements of weaners, especially in the winter months, there is high energy consumption for rearing piglets. Furthermore the economic trend shows increasing energy costs. Thus, it is necessary, inter alia, to evaluate particular technologies to minimize the demand of energy consumption in order to reduce the costs. Air-to-air tube-type heat exchanger offers a convective transmission of heat from waste air to inlet air by using a specific airflow-control-system. Above all the heat energy can be decreased due to the warmed up inlet air which leads to an amplitude attenuation especially in the winter months. The Institute of Agricultural Engineering from the University of Bonn has examined the air-to-air tube-type heat exchanger of the Moeller GmbH company for the purpose of acquiring representative data of this regenerative technology. (orig.)

  5. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and ... having trouble with the heat. If a heat wave is predicted or happening… - Slow down. Avoid strenuous ...

  6. Heat Islands

    Science.gov (United States)

    EPA's Heat Island Effect Site provides information on heat islands, their impacts, mitigation strategies, related research, a directory of heat island reduction initiatives in U.S. communities, and EPA's Heat Island Reduction Program.

  7. Quantifying canal leakage rates using a mass-balance approach and heat-based hydraulic conductivity estimates in selected irrigation canals, western Nebraska, 2007 through 2009

    Science.gov (United States)

    Hobza, Christopher M.; Andersen, Michael J.

    2010-01-01

    The water supply in areas of the North Platte River Basin in the Nebraska Panhandle has been designated as fully appropriated or overappropriated by the Nebraska Department of Natural Resources (NDNR). Enacted legislation (Legislative Bill 962) requires the North Platte Natural Resources District (NPNRD) and the NDNR to develop an Integrated Management Plan (IMP) to balance groundwater and surface-water supply and demand in the NPNRD. A clear understanding of the groundwater and surface-water systems is critical for the development of a successful IMP. The primary source of groundwater recharge in parts of the NPNRD is from irrigation canal leakage. Because canal leakage constitutes a large part of the hydrologic budget, spatially distributing canal leakage to the groundwater system is important to any management strategy. Surface geophysical data collected along selected reaches of irrigation canals has allowed for the spatial distribution of leakage on a relative basis; however, the actual magnitude of leakage remains poorly defined. To address this need, the U.S. Geological Survey, in cooperation with the NPNRD, established streamflow-gaging stations at upstream and downstream ends from two selected canal reaches to allow a mass-balance approach to be used to calculate daily leakage rates. Water-level and sediment temperature data were collected and simulated at three temperature monitoring sites to allow the use of heat as a tracer to estimate the hydraulic conductivity of canal bed sediment. Canal-leakage rates were estimated by applying Darcy's Law to modeled vertical hydraulic conductivity and either the estimated or measured hydraulic gradient. This approach will improve the understanding of the spatial and temporal variability of canal leakage in varying geologic settings identified in capacitively coupled resistivity surveys. The high-leakage potential study reach of the Tri-State Canal had two streamflow-gaging stations and two temperature monitoring

  8. 不同升温速率下城市污水污泥热解特性及动力学研究%Pyrolysis characteristics of municipal wastewater sewage sludge under different heating rate

    Institute of Scientific and Technical Information of China (English)

    管志超; 胡艳军; 钟英杰

    2012-01-01

    利用差热-热重分析法和Coats-Redfern积分法,对杭州某污水处理厂污泥在不同升温速率下的热解特性及反应动力学特征进行研究.实验结果表明,热解温度从室温升至900℃时,污泥热解过程可分为4个失重阶段;升温速率对污泥热解转化率、挥发分析出温度以及最大失重率等热解特性参数都有显著影响.升温速率越高污泥最大失重率越大;而较低的升温速率延迟了污泥热解反应时间,导致污泥失重量相对较大.根据Coats-Redfern积分法计算结果,污泥在氮气氛围下的热解反应为二级反应模式.提高升温速率可显著增加污泥热解的表观活化能和频率因子.%The differential scanning calorimetry, simultaneous thermal analysis and theoretical analysis method of Coats-Redfern were employed to study the pyrolysis process and kinetics characteristics of Hangzhou municipal wastewater sewage sludge under various heating rates. It was found that the pyrolysis process of sludge from indoor temperature to 900℃ could devided into 4 the weight loss stages. Heating rate had obvious effects on pyrolysis process of the sludge. Higher heating rate resulted in higher maximun weight loss rate, while lower heating rate could extend the pyrolysis time and finally incresed the sludge weight loss. Base on the results of Coats-Redfern integration method, the pyrolysis process of sludge under N2 atmosphere was belongs to two-class reaction. The knetic characteristics of the sludge pyrolysis under different heating rates was caluculted. Results showed that the apparent activation energy and the frequency factor of were greatly increased after increasing heating rate.

  9. Study of Concentrations of Available Cations and Anions in PM2.5 in the Air of Twelfth Region of Tehran City

    Directory of Open Access Journals (Sweden)

    Hossean Arfaeinia

    2017-04-01

    Full Text Available Background: In the last few decades, the city's air quality has become a major concern; especially there is strong evidence about health effects of particulate matter in urban communities.In addition to suspended particles concentration, the ionic part of suspended particles is also very important, So that some studies  ions like Sulfate is the reson of increasing the respiratory diseases.So the aim of this study was to study of concentration of PM2.5 particles and their ionic componentsincluding major anions and cations in twelfth region of Tehran city in 2013. Materials & Methods: This cross - sectional study was conducted in the air of twelfth region of Tehran. PM2.5 concentration was calculated with sampling by frmOMNITMAmbient Air Sampler with PTFE filter with a diameter of 47 mm and through the weight measurement.Concentration of anions and cations which had associated with PM2.5 particles was read after collected sample preparation and injection to device Ion Chromatography (IC Metrohm 850 model. Correlation matrix was calculated between anions and cations. Data analysis was carried out by Excel and SPSS version 18 and One-Way ANOVA test. Results: The mean daily concentration of PM2.5 particles was 19.41 µg/m3 during the study. One-Way ANOVA test showed a significant difference at the 0.05 level between PM2.5 concentrations on different days of the week. Concentrations for sodium, potassium, ammonium, calcium, magnesium, sulfate, nitrate, chloride were obtained 0.28, 0.06, 0.49, 0.87, 0.63, 56.3, 1.43 and 0.71 µg/m3, respectively, and no value was detected for fluoride and nitrite. Balance between anions and cations were calculated and the correlation coefficient (R2 were obtained 0.972 between the anions and cations. Conclusion The mean concentrations of PM2.5 was higher than the air standards in Iran and WHO guidelines (25 µg/m3 and EPA standards (35 µg/m3. In a study reported that the One-Way ANOVA test between particle

  10. Quantitative Relationship between NTU and Fluid Temperature and Ratio of Heat Capacity vs.Flow Rate%NTU与流体温度及热容流率比间的定量关系研究

    Institute of Scientific and Technical Information of China (English)

    张洪流; 赵权; 陈明功

    2011-01-01

    The calculation of operation model of heat exchanger usually needs repetitious trial and error or look up e - NTU figure, which is complex and has some error. In order to avoid these problems, the quantitative relationship between the number of heat - transfer units ( NTU) and fluid temperature and the ratio of heat capacity vs. Flow rate for one -way no phase changed heat exchanger was studied. By this way, a formula was obtained. Then the formula and the chart were verified and analyzed by an practical example. The results showed that by u-sing the formula to calculate the fluid temperature and consumption of media can avoid repetitious trial and error or look up e - NTU figure. The method is simpler and more precocious. Ratio of heat capacity vs. Flow rate has a critical value. In order to get economical heat transfer process, the ratio of heat capacity vs. Flow rate should be kept below its critical value in process of heat exchanger design and selection.%换热器操作型问题计算往往需反复试差或查取算图,计算繁复或有误差.为回避试差或查算图,对单程无相变换热器传热单元数与流体温度及热容流率比间的定量关系进行研究,导出了计算公式,对导出公式及获得的计算图表通过实例检验和分析.研究结果表明:用导出公式确定流体温度及介质消耗量可避免试差或查算图,方法简便、精度高;热客流率比存在临界值,在换热器设计及应用过程中需控制在临界值以下,以确保换热过程的经济性.

  11. Serotonin transporter binding in the hypothalamus correlates negatively with tonic heat pain ratings in healthy subjects: A [11C]DASB PET study

    DEFF Research Database (Denmark)

    Kupers, Ron; Frokjaer, Vibe G.; Erritzoe, David

    2010-01-01

    analysis revealed a positive correlation between pain tolerance and SERT binding in the hypothalamus (r = 0.53; p = 0.02) although this was not seen in the parametric analysis. These data extend our earlier observation that cortical 5-HT receptors co-determine responses to tonic but not to phasic pain......There is a large body of evidence that the serotonergic system plays an important role in the transmission and regulation of pain. Here we used positron emission tomography (PET) with the serotonin transporter (SERT) tracer [11C]DASB to study the relationship between SERT binding in the brain...... and responses to noxious heat stimulation in a group of 21 young healthy volunteers. Responses to noxious heat stimuli were assessed in a separate psychophysical experiment and included measurements of pain threshold, pain tolerance, and responses to phasic noxious heat stimuli and to a long lasting (7-minute...

  12. 太阳能雾化脱盐系统热能利用率的研究%Study on the heat energy utilization rate of the solar energy pulverization desalination system

    Institute of Scientific and Technical Information of China (English)

    张大帅; 费学宁; 苏润西; 苑宏英; 姜远光

    2016-01-01

    在构建太阳能雾化脱盐系统的基础上对该系统处理浓盐水的热能利用率进行了研究,考察了辐照值、空气流量、气水比等因素对系统热能利用率的影响。结果表明,系统的热能利用率随着辐照值的升高呈现减小趋势,随着气水比、空气流量的增大呈现先增大后减小的趋势。系统的热能利用率与空气流量存在二次抛物线关系。%Based on the esta blishment of solar energy pulverization desalination system ,the heat energy utilization rate of concentrated brine treated by this system has been studied. The influences of the factors ,such as irradiation values,air flow,gas water ratio,etc. on the heat energy utilization of the system are investigated. The results show that the heat energy utilization rate of the system presents a tendency of decrease with the increase of irradiation va-lues;and the heat energy utilization of the system also presents a tendency of increase first,and then decrease,with the increase of gas water ratio,and air flow. There is a quadratic parabolic relationship between the heat energy utilization rate of the system and the air flow.

  13. 安全生产"十二五"规划若干统计指标考量%Research on several indicators in the twelfth five-year program for work safety

    Institute of Scientific and Technical Information of China (English)

    刘铁民; 任智刚

    2011-01-01

    生产安全事故统计指标是安全生产监督管理及宏观决策重要依据.为进一步完善我国职业伤害统计指标体系,对安全生产规划中若干指标的科学性和实用性以及存在问题进行了探索.在进行初步实验计算、理论分析和国内外安全生产事故主要统计指标特点对比研究后,提出:在该规划指标中调整或删去"亿元国内生产总值死亡率";增加非致死性事故统计数据,以能更好代表职业伤害事故总量;适度应用重特大事故起数指标和提高十万人死亡率统计指标精确性等几点建议.作者认为应加强职业伤害指标体系研究,从而尽快实现我国统计指标与国际接轨,在中重现中国职业伤害统计数据.%Occupational injury indicators play important roles in work safety administration and macro decision-making.To further improve the system of statistical indicators of occupational injury, the scientific and practicability as well as problems about several occupational indicators in the Twelfth Five-year program for work safety were studied.Based on preliminary calculation, theoretical analysis and comparison of main occupational injury indicators at home and abroad, we gave a few suggestions, namely adjusting or deleting the indicator fatal rate per one hundred million GDP, increasing non-fatal accident statistic indicators to better representative of the total occupational injuties, applying indicators of major accidents appropriately and increasing accuracy of the indicator fatal numbers per 100000 workers.We advised that we should strengthen research on occupational injury indicators so as to consistent with international standards of occupational injury statistical indicators soon as possible, and to make occupational injury data of China return in the Yearbook of International Labor Statistics.

  14. The Deformation Rate of Smooth Muscle Cells in Vessel Walls After Short-Duration Heating Dilatation in a Porcine Model Ex Vivo and In Vivo

    OpenAIRE

    Kunio, Mie; Arai, Tsunenori

    2012-01-01

    We have proposed a novel short-duration thermal angioplasty with uniform temperature distribution. Although the dilatation mechanism of our short-duration heating dilatation was reported in our previous study, the influences on smooth muscle cells (SMCs) are not sufficiently understood. We studied the influences on SMCs in terms of shape change and discussed the relationship between the SMCs’ shape change and dilatation mechanism ex vivo and in vivo. We found that the SMCs were fixed in the s...

  15. Heat Stress

    Science.gov (United States)

    ... Publications and Products Programs Contact NIOSH NIOSH HEAT STRESS Recommend on Facebook Tweet Share Compartir NEW OSHA- ... hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational ...

  16. Influence of heat transfer on walls due to aerosol decomposition rate in the containment building of nuclear power plants during heavy incidents; Einfluss des Waermeuebergangs an Waenden auf die Aerosolabbaurate im Sicherheitsbehaelter von Kernkraftwerken bei schweren Stoerfaellen

    Energy Technology Data Exchange (ETDEWEB)

    Braun, T.

    2004-07-01

    Today, German nuclear power plants are leading in safety standards worldwide. Increasing potentials arise continuously along with improvements in technology. One of these potentials is the best-estimate simulation of fission product transport in case of a severe accident. A main part of the fission products is allocated on aerosols. Therefore, the aerosol behavior before containment leakage is important for the radioactive source term to the environment. Having a good knowledge about the main aerosol phenomena, it is possible to simulate them numerically. This enables to develop and test safety measures to limit damages before accidents occur. Within this study, the main aerosol phenomena have been ascertained and accordingly classified into formation, transport and reduction. On this basis, simulations of one- and multi-component aerosol experiments of the KAEVER series have been performed with the COCOSYS code. Due to an overprediction of the computed volume condensation rate, the results showed an overestimation of the reduction rate of insoluble aerosols. The reason was found to be the underestimation of the wall condensation rate. Based on an additional plain thermal hydraulic multi compartment experiment, these uncertainties in the wall heat transfer correlations were investigated in detail. The results show a strong dependency between the wall condensation rate and the convective heat transfer, resp. the characteristic length. In case of mainly forced convection, correct values for the characteristic length led to an underestimation of the calculated heat transfer coefficients. The analysis of the heat transfer models show an inconsistency in the coupling of free and forced convection. Therefore, an improved and consistent convection model has been developed and implemented. Both models have been tested on different experiments. Although the new model shows only minor improvements, it could be proven that the influence for forced convection is significant

  17. Heating automation

    OpenAIRE

    Tomažič, Tomaž

    2013-01-01

    This degree paper presents usage and operation of peripheral devices with microcontroller for heating automation. The main goal is to make a quality system control for heating three house floors and with that, increase efficiency of heating devices and lower heating expenses. Heat pump, furnace, boiler pump, two floor-heating pumps and two radiator pumps need to be controlled by this system. For work, we have chosen a development kit stm32f4 - discovery with five temperature sensors, LCD disp...

  18. Multileg Heat-Pipe Evaporator

    Science.gov (United States)

    Alario, J. P.; Haslett, R. A.

    1986-01-01

    Parallel pipes provide high heat flow from small heat exchanger. Six parallel heat pipes extract heat from overlying heat exchanger, forming evaporator. Vapor channel in pipe contains wick that extends into screen tube in liquid channel. Rods in each channel hold wick and screen tube in place. Evaporator compact rather than extended and more compatible with existing heat-exchanger geometries. Prototype six-pipe evaporator only 0.3 m wide and 0.71 m long. With ammonia as working fluid, transports heat to finned condenser at rate of 1,200 W.

  19. Optimal design of the separate type heat pipe heat exchanger

    Institute of Scientific and Technical Information of China (English)

    YU Zi-tao; HU Ya-cai; CEN Ke-fa

    2005-01-01

    Separate type heat pipe heat exchangers are often used for large-scale heat exchanging. The arrangement of such a heat exchanger conveniently allows heat input to and output from the heat exchanger at remote locations. The traditional method of designing an ordinary HPHE (heat pipe heat exchanger) is commonly applied in the separate type exchanger design, but the calculations have to be carried out separately, which makes it very complicated. In this work, the ε-NTU (effectiveness-Number of Transfer Units) method was applied for optimization analysis of single- or multi-level separate type heat pipe heat exchangers. An optimizing formula for single-level separate type heat pipe heat exchangers was obtained. The optimizing principles of effectiveness-NTU and heat transfer rate by the equal distribution method for multi-level separate type heat pipe heat exchanger are presented. The design of separate type heat pipe heat exchangers by the optimizing method is more convenient and faster than by the traditional method.

  20. Heat and mass transfer in a dissociated laminar boundary layer of air with consideration of the finite rate of chemical reaction

    Science.gov (United States)

    Oyegbesan, A. O.; Algermissen, J.

    1986-01-01

    A numerical investigation of heat and mass transfer in a dissociated laminar boundary layer of air on an isothermal flat plate is carried out for different degrees of cooling of the wall. A finite-difference chemical model is used to study elementary reactions involving NO2 and N2O. The analysis is based on equations of continuity, momentum, energy, conservation and state for the two-dimensional viscous flow of a reacting multicomponent mixtures. Attention is given to the effects of both catalyticity and noncatalyticity of the wall.

  1. Heating rate effect on the evolution of texture in (Bi,Pb)2Sr2Ca2Cu3O10 Ag-sheathed tapes

    DEFF Research Database (Denmark)

    Grivel, J.C.; Raittila, J.; Xu, G.J.

    2005-01-01

    Bi2223/Ag tapes have been produced by the powder-in-tube technique. The evolution of texture during the first heat treatment has been studied by means of in situ synchrotron radiation diffraction. Using various heating rates (1, 2 and 4 degrees C min(-1)), it wag found that the kinetics of prefer......Bi2223/Ag tapes have been produced by the powder-in-tube technique. The evolution of texture during the first heat treatment has been studied by means of in situ synchrotron radiation diffraction. Using various heating rates (1, 2 and 4 degrees C min(-1)), it wag found that the kinetics...

  2. Chiral brownian heat pump.

    Science.gov (United States)

    van den Broek, M; Van den Broeck, C

    2008-04-04

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  3. Chiral Brownian heat pump

    OpenAIRE

    Van Den Broek, Martijn; Van Den Broeck, Christian

    2007-01-01

    We present the exact analysis of a chiral Brownian motor and heat pump. Optimization of the construction predicts, for a nanoscale device, frequencies of the order of kHz and cooling rates of the order of femtojoule per second.

  4. The Twelfth Five-Year Plan of China's dyeing and finishing industry%印染行业“十二五”发展规划

    Institute of Scientific and Technical Information of China (English)

    中国印染行业协会

    2012-01-01

    During the " Eleventh Five-Year" period, the production and marketing of China's dyeing and finishing industry kept sustained growth, structural adjustment gained substantial achievements, energy saving and emission reduction firmly pushed forward. The development model appeared to transform from quantity-oriented growth pattern to quality-oriented one. During the " Twelfth Five-Year" period, the dyeing and finishing industry should put more emphasis on technology advance, product research and development, resource saving and environment protection The industry need to promote the products' quality and added values, increase the production efficiency, reduce the production cost and the pollutant release, improve profitability and the quality and efficiency of economic growth, and speed up the transformation from quantity-oriented growth pattern to quality-oriented one%“十一五”期间,我国印染行业生产销售持续增长,经济效益稳步提高,产业结构调整取得成效,节能减排扎实推进;产业发展从数量型增长向质量效益型增长转变明显.“十二五”期间,印染行业应更加注重科技进步,注重产品研发和市场营销,注重资源节约和环境保护,提升产品质量和附加值,提高生产效率,降低生产成本,减少污染物排放,提升企业的赢利能力和水平,提高经济增长的质量和效益,推动行业由资源数量型增长向质量效益型增长转变.

  5. Heat Pipe Materials Compatibility

    Science.gov (United States)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1976-01-01

    An experimental program to evaluate noncondensable gas generation in ammonia heat pipes was completed. A total of 37 heat pipes made of aluminum, stainless steel and combinations of these materials were processed by various techniques, operated at different temperatures and tested at low temperature to quantitatively determine gas generation rates. In order of increasing stability are aluminum/stainless combination, all aluminum and all stainless heat pipes. One interesting result is the identification of intentionally introduced water in the ammonia during a reflux step as a means of surface passivation to reduce gas generation in stainless-steel/aluminum heat pipes.

  6. Effect of transfer of one or two in vitro-produced embryos and post-transfer administration of gonadotropin releasing hormone on pregnancy rates of heat-stressed dairy cattle.

    Science.gov (United States)

    Franco, M; Block, J; Jousan, F D; de Castro e Paula, L A; Brad, A M; Franco, J M; Grisel, F; Monson, R L; Rutledge, J J; Hansen, P J

    2006-07-15

    Pregnancy rates following transfer of an in vitro-produced (IVP) embryo are often lower than those obtained following transfer of an embryo produced by superovulation. The purpose of the current pair of experiments was to examine two strategies for increasing pregnancy rates in heat stressed, dairy recipients receiving an IVP embryo. One method was to transfer two embryos into the uterine horn ipsilateral to the CL, whereas the other method involved injection of GnRH at Day 11 after the anticipated day of ovulation. In Experiment 1, 32 virgin crossbred heifers and 26 lactating crossbred cows were prepared for timed embryo transfer by being subjected to a timed ovulation protocol. Those having a palpable CL were randomly selected to receive one (n = 31 recipients) or two (n = 27 recipients) embryos on Day 7 after anticipated ovulation. At Day 64 of gestation, the pregnancy rate tended to be higher (P = 0.07) for cows than for heifers. Heifers that received one embryo tended to have a higher pregnancy rate than those that received two embryos (41% versus 20%, respectively) while there was no difference in pregnancy rate for cows that received one or two embryos (57% versus 50%, respectively). Pregnancy loss between Day 64 and 127 only occurred for cows that received two embryos (pregnancy rate at Day 127=17%). Between Day 127 and term, one animal (a cow with a single embryo) lost its pregnancy. There was no difference in pregnancy rates at Day 127 or calving rates between cows and heifers, but females that received two embryos had lower Day-127 pregnancy rates and calving rates than females that received one embryo (P cows were synchronized for timed embryo transfer as in Experiment 1. Cows received a single embryo in the uterine horn ipsilateral to the ovary containing the CL and received either 100 microg GnRH or vehicle at Day 11 after anticipated ovulation (i.e. 4 days after embryo transfer). There was no difference in pregnancy rate for cows that received the Gn

  7. Heat pumps

    CERN Document Server

    Macmichael, DBA

    1988-01-01

    A fully revised and extended account of the design, manufacture and use of heat pumps in both industrial and domestic applications. Topics covered include a detailed description of the various heat pump cycles, the components of a heat pump system - drive, compressor, heat exchangers etc., and the more practical considerations to be taken into account in their selection.

  8. Calculation of Maximum Waste Heat and Recovery Rate of Liquid and Gas Fuels%液气燃料烟气的最大余热量与节能率计算研究

    Institute of Scientific and Technical Information of China (English)

    丛永杰

    2016-01-01

    The consumption of various liqui d oil and gas fuel grows rapidly in Chinese energy structure. The discharged flue's temperature is generally 160℃ ~180℃ after these fuels are combusted. This part of energy can be used as secondary energy, though whose grade is low. A lot of H elements are in the form of liquid and gas fuels, and the vapor is the flue's main ingredi-ents. In this paper, the waste heat quantity and recovery rate of 0# light diesel oil and natural gas's flue is calculated, whose tem-perature is from 180℃ to 25℃ at the condition of 1 atm. In the 0# light diesel's flue, the residual heat's proportion of the vapor's heat is about 55. 08%. In the natural gas's flue, which proportion is about 79. 41%. Moreover, the vapor's latent heat is about 3/4. Therefore, recovering the latent heat of vapor is of great significance for the heat recovery of the low temperature waste heat.%在中国能源结构中,燃油与天然气所占比例迅速上升.燃烧后排烟温度一般为160℃~180℃,仍含有较多能量,可以二次利用.本文通过对液、气体燃料中具有代表性的0号轻质柴油及天然气烟气的余热量与节能率进行计算,发现低温烟气余热中的水蒸气余热量占有很大比例,柴油烟气为55.08%,天热气烟气为79.41%.回收烟气余热,尤其是其中水蒸汽的潜热对低温烟气的热回收具有重要意义.若有效回收利用,既是对一次能源的二次利用,更符合"十三五"期间国家节能减排的相关政策要求.

  9. 宝钢三期焦炉高开工率加热调节实践%Heating regulation practice for high pushing rate of Baosteel 3rd coke oven battery

    Institute of Scientific and Technical Information of China (English)

    李勇; 余国普

    2015-01-01

    This paper introduces the thermal regulation practice of Baosteel JNX60-2 type coke oven battery for 125%pushing rate, analyzes the difficulties for high pushing rate.High pushing rate can be achieved by regulating the temperature distribution in the chamber during production and heating schedule.%介绍了JNX60-2型焦炉125%高开工率生产的热工调节实践,分析了高开工率的生产难点,调整了生产条件下的焦炉温度分布,总结提出了高开工率的加热制度。

  10. Temperature increase of Zircaloy-4 cladding tubes due to plastic heat dissipation during tensile tests at 0.1-10 s-1 strain rates

    Science.gov (United States)

    Hellouin de Menibus, Arthur; Auzoux, Quentin; Besson, Jacques; Crépin, Jérôme

    2014-11-01

    This study is focused on the impact of rapid Reactivity Initiated Accident (RIA) representative strain rates (about 1 s-1 NEA, 2010) on the behavior and fracture of unirradiated cold work stress relieved Zircaloy-4 cladding tubes. Uniaxial ring tests (HT) and plane strain ring tensile tests (PST) were performed in the 0.1-10 s-1 strain rate range, at 25 °C. The local temperature increase due to plastic dissipation was measured with a high-speed infrared camera. Limited temperature increases were measured at 0.1 s-1 strain rate. Limited but not strongly localized temperature increases were measured at 1 s-1. Large temperature increase were measured at 5 and 10 s-1 (142 °C at 5 s-1 strain rate in HT tests). The local temperature increase induced heterogeneous temperature fields, which enhanced strain localization and resulted in a reduction of the plastic elongation at fracture.

  11. Passive Solar Heating Residences.

    Science.gov (United States)

    1979-07-01

    temperatures of indes 1, 0, 8, and 7. Figure C-2 shows the rate of solair radiation absorption in node 1 (the prinnary solar heat souirce., the rate of...energy. The heating is basically done by letting the sun’s radiation into a building’s interior, to be stored in some kind of thermal mass or to heat up...solar radiation through south facing windows or clerestroies to be stored in the walls or floor of the house. Thermal storage in a wall or roof allows

  12. PROCEEDINGS OF THE 1998 OIL HEAT TECHNOLOGY CONFERENCE

    Energy Technology Data Exchange (ETDEWEB)

    MCDONALD,R.J.

    1998-04-01

    The 1998 Oil Heat Technology Conference will be held on April 7--8 at Brookhaven National Laboratory (BNL) under sponsorship by the US Department of Energy, Office of Building Technologies, State and Community Programs (DOE/BTS). The meeting will be held in cooperation with the Petroleum Marketers Association of America (PMAA). The 1998 Oil Heat Technology Conference, will be the twelfth since 1984, is an important technology transfer activity and is supported by the ongoing Combustion Equipment Technology (Oilheat R and D) program at BNL. The reason for the conference is to provide a forum for the exchange of information and perspectives among international researchers, engineers, manufacturers and marketers of oil-fired space-conditioning equipment. They will provide a channel by which information and ideas can be exchanged to examine present technologies, as well as helping to develop the future course for oil heating advancement. These conferences also serve as a stage for unifying government representatives, researchers, fuel oil marketers, and other members of the oil-heat industry in addressing technology advancements in this important energy use sector. The specific objectives of the Conference are to: (1) Identify and evaluate the current state-of-the-art and recommend new initiatives for higher efficiency, a cleaner environment, and to satisfy consumer needs cost-effectively, reliably, and safely; and (2) Foster cooperative interactions among federal and industrial representatives for the common goal of sustained economic growth and energy security via energy conservation.

  13. 内蒙古自治区“十二五”期间煤电发展空间测算%Calculation of coal power development during the “Twelfth Five Planning” in Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    卢艳丽; 宋志博

    2015-01-01

    根据内蒙古自治区2010年的 SO2和 NOx 排放现状,结合现行减排政策和排放标准要求,分析“十二五”期间内蒙古现役源的 SO2和 NOx 减排潜力。根据“十二五”SO2和 NOx 总量控制目标,分析新源可用的排放指标空间。测算“十二五”期间非电力行业的污染物排放增量,在此基础上分析电力行业排放指标空间可供发展的新建燃煤机组规模。%According to the SO2 and NOx emission status of the Inner Mongolia in 2010,according to the current emission reduction policies and emission standards, SO2 and NOx emission reduction potential of Inner Mongolia active source analysis of the " Twelfth Five Planning " period. According to the SO2 and NOx total control objectives of the "Twelfth Five Planning ", analysis of space available source emission index. Calculation of the " Twelfth Five Planning " period in nonpower industry increment of pollutant emissions, the scale of the new coal-fired units on the basis of analysis of emission index of electric power industry for the development of space.

  14. The effects of mischmetal, cooling rate and heat treatment on the eutectic Si particle characteristics of A319.1, A356.2 and A413.1 Al-Si casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sebaie, O. El; Samuel, A.M. [Universite du Quebec a Chicoutimi, Chicoutimi, Quebec, G7H 2B1 (Canada); Samuel, F.H. [Universite du Quebec a Chicoutimi, Chicoutimi, Quebec, G7H 2B1 (Canada)], E-mail: fhsamuel@uqac.ca; Doty, H.W. [GM Powertrain Group, Metal Casting Technology, Inc., Milford, NH 03055 (United States)

    2008-05-15

    The effects of mischmetal, cooling rate and heat treatment on the eutectic Si particle characteristics of A319.1, A356.2 and A413.1 Al-Si casting alloys were investigated and recorded for this study. Mischmetal was added to the alloys in the form of Al-20% mischmetal master alloy to produce four levels of mischmetal addition (0, 2, 4 and 6 wt%). The alloys were also modified with strontium ({approx}250 ppm) to study the combined modification effect of Sr and mischmetal at both high and low cooling rates corresponding to dendrite arm spacings of {approx}40 and 120 {mu}m, respectively. The alloys were subjected to solution heat treatment (495 deg. C/8 h for A319.1 and A413.1 alloys, and 540 deg. C/8 h for A356.2 alloy) to investigate its effect on the eutectic Si particle morphology. An optical microscope-image analyzer system was used to measure the characteristics of eutectic Si particles such as area, length, roundness ratio and aspect ratio, in order to monitor the modifying effect of mischmetal, as well as the combined modification effect of mischmetal and Sr. For each alloy sample examined, the Si particle characteristics were measured over an area of 50 fields and the average particle characteristics were thus determined. The eutectic Si particle measurements revealed that partial modification was obtained with the addition of mischmetal while full modification was achieved with the addition of Sr in the as-cast condition, at both high and low cooling rates. The interaction between Sr and mischmetal was observed to weaken the effectiveness of Sr as a Si particle-modifying agent. This effect was particularly evident at the low cooling rate. During solution heat treatment, the eutectic Si particles in the non-modified alloys underwent rapid coarsening, otherwise known as Ostwald ripening, whereas those in the Sr-modified alloys exhibited a high spheroidization rate. The coarsening was evidenced by an increase in the thickness of the Si particles, clearly

  15. Heat transfer and fire spread

    Science.gov (United States)

    Hal E. Anderson

    1969-01-01

    Experimental testing of a mathematical model showed that radiant heat transfer accounted for no more than 40% of total heat flux required to maintain rate of spread. A reasonable prediction of spread was possible by assuming a horizontal convective heat transfer coefficient when certain fuel and flame characteristics were known. Fuel particle size had a linear relation...

  16. Heat pumps

    CERN Document Server

    Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski

    2013-01-01

    Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o

  17. Fault-Tolerant Heat Exchanger

    Science.gov (United States)

    Izenson, Michael G.; Crowley, Christopher J.

    2005-01-01

    A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

  18. Duplex Stirling gas fired heating only heat pump

    Science.gov (United States)

    Beale, W.

    1982-03-01

    In phase I the Duplex Stirling Gas fired Heat Pump was analyzed with the aid of the Sunpower third order simulation and optimization code and found to show heating COP of 1.7 at the rating point of 8 C (17 F) with a heat delivery of 10 kW. Also it was found that a direct heat exchange between working fluid and source and sink air was consistent with high COP in the heat pump, thus eliminating the need for an intermediate heat transfer fluid and its associated pumps and controls. Further, it was demonstrated in the simulation that the heat engine power output could be matched to the heat pump load over the range of source temperatures without need of complex control systems. Cost estimates, along with COP figures from the analysis indicated a payback time of 2 to 4 years in completion with existing combustion heating systems in northern climates.

  19. Assessment of potential Rio Grande do Norte, Brazil, clays when subjected to high rates of heating; Avaliacao da potencialidade de argilas do Rio Grande do Norte quando submetidas a elevadas taxas de aquecimento

    Energy Technology Data Exchange (ETDEWEB)

    Filgueira, R.L.; Pereira, L.M.; Dutra, R.P.S.; Nascimento, R.M. [Universidade Federal do Rio Grande do Norte (DEMat/CT/UFRN), Natal, RN (Brazil). Centro de Tecnologia. Dept. de Engenharia de Materiais

    2009-07-01

    In this work we study three clays of the state of Rio Grande do Norte, Brazil, to evaluate the potential them when subjected to high rates of heating. The samples were formed by pressing and subject to rates of 5 deg C / min, 10 deg C / min and 15 deg C / min, with temperature of 950 deg C. This study determined the technological properties of the samples. The mineralogical composition was identified by X-ray diffraction. The chemical composition was determined by Xray fluorescence. The Atterberg limits, were used to classify the samples on the plasticity. Were also performed: dilatometry, size analysis and scanning electron microscopy. The examination of the processing variables and the intrinsic characteristics of each material indicates that the RX clay showed the best results for the manufacture of blocks and tiles. The techniques used in this study were efficient and the initial objectives were achieved. (author)

  20. Experimental investigation of heat transfer and effectiveness in corrugated plate heat exchangers having different chevron angles

    Science.gov (United States)

    Kılıç, Bayram; İpek, Osman

    2017-02-01

    In this study, heat transfer rate and effectiveness of corrugated plate heat exchangers having different chevron angles were investigated experimentally. Chevron angles of plate heat exchangers are β = 30° and β = 60°. For this purpose, experimentally heating system used plate heat exchanger was designed and constructed. Thermodynamic analysis of corrugated plate heat exchangers having different chevron angles were carried out. The heat transfer rate and effectiveness values are calculated. The experimental results are shown that heat transfer rate and effectiveness values for β = 60° is higher than that of the other. Obtained experimental results were graphically presented.

  1. Preliminary Study on Heating Rate Calculation for PWR Internals by Three-Dimensional SN Method%三维离散纵标方法在堆内构件释热率计算中的初步应用

    Institute of Scientific and Technical Information of China (English)

    杨寿海; 陈义学; 王伟金; 靳忠敏; 陆道纲

    2012-01-01

    Based on the American H.B.Robinson-2 pressure vessel benchmark, the neutron spectrum in surveillance capsule and reaction rates for some species have been obtain by three-dimensional (3-D) discrete ordinates (Sn) method code (TORT). The results show that, the neutron spectrum in surveillance capsule makes good agreement with the benchmark, and the C/M of reaction rates for some species is 1.04±0.04 by TORT code. Then, the heat release rate distribution over reactor components has been calculated by TORT code and MCNP program for Ningde Nuclear Power Plant in Fujian China, and compared with each other. Finally, the application of TORT code in the calculation of the heating rate for PWR internals is presented and discussed.%以美国H.B.Robinson-2#机组反应堆压力容器(RPV)基准实验的参数为输入数据,采用三维离散纵标方法程序( TORT)计算压力辐照监督管处中子能谱及典型核素的活度值.计算得到的辐照监督管处中子能谱与基准实验结果趋势一致、吻合较好;典型核素活度的计算值与测量值之比(C/M)为1.04±0.04.用TORT对福建宁德核电站堆内构件释热率分布进行初步计算,并与蒙特卡罗方法(MCNP)的计算结果相比较,两种方法的结果表现出良好的一致性.最后对TORT程序应用于堆内释热率计算进行讨论.

  2. Heat rate variability and dyssomnia and their correlations to neurological defects in cerebral infarction patients complicated by insomnia A concurrent non-randomized case-control study

    Institute of Scientific and Technical Information of China (English)

    Jianping Chu; Xueli Shen; Jun Fan; Changhai Chen; Shuyang Lin

    2008-01-01

    BACKGROUND: Heart rate variability refers to the beat-to-beat alteration in heart rate. It is usually a slight periodic variation of R-R intervals. Much information of autonomic nerve system balance can be obtained by measuring the heart rate variability of patients. It remains to be shown whether heart rate variability can be used as an index for determining the severity of insomnia and cerebral infarction. OBJECTIVE: This study aimed to analyze the correlation for each frequency spectrum parameter of heart rate variability with an insomnia index, as well as the degree of neurological defects in patients with simple cerebral infarction and cerebral infarction complicated by insomnia. The goal was to verify the feasibility of frequency spectrum parameters for heart rate variability as a marker for insomnia and cerebral infarction. DESIGN: A case-control observation. SETTING: Department of Neurology, First Hospital Affiliated to China Medical University. PARTICIPANTS: Sixty inpatients, and/or outpatients, with cerebral infarction were admitted to the 202 Hospital of Chinese PLA between December 2005 and October 2006, confirmed by CT, and recruited to the study. According to the insomnia condition (insomnia is defined by a Pittsburgh Sleep Quality Index score > 7), the patients were assigned to a simple cerebral infarction group and a cerebral infarction complicated by insomnia group, with 30 subjects in each group. Thirty additional subjects, who concurrently received ex-aminations and were confirmed to not suffer from cerebral infarction and insomnia, were recruited into the control group. Written informed consent was obtained from each subject for laboratory specimens. The pro-tocol was approved by the Hospital's Ethics Committee. METHODS: Following admission, each subject's neurological impairment was assessed with the National Institutes of Health Stroke Scale and Pittsburgh Sleep Quality Index. Heart rate variability of each subject was measured with an

  3. Effect of heat treatment and cooling rate on minority carrier lifetime of Czochralski silicon%热处理和冷却速率对直拉单晶硅少子寿命的影响

    Institute of Scientific and Technical Information of China (English)

    周潘兵; 柯航; 周浪

    2012-01-01

    Effects of heating temperature and cooling rate on the minority carrier lifetime and the interstitial iron concentration of Czochralski silicon(Cz-Si) were investigated. The results show that the interstitial iron concentration is higher and the minority carrier lifetime is lower than the original level when the Cz-Si are heated in the range of 300-1050 ℃ for 40 min and cooled to room temperature at a rate as fast as 50 ℃/s, and the interstitial iron concentration increases and the minority carrier lifetime decreases with increase of heating temperature. When the Cz-Si wafers are heated in the range of 900-1000 ℃ for 40 min and cooled to room temperature at a rate as fast as 50 ℃/s, above 90% of the iron in silicon is in the form of iron precipitates while the other is kept as interstitial iron. When the Cz- Si wafers are heated at 800, 900 and 1000 ℃ for 40 min, followed by cooling at different rates, the interstitial iron concentration increases and the minority carrier lifetime decreases with increase of the cooling rate from 0. 017 to 50 ℃/s.%研究了加热温度与冷却速率对热处理直拉单晶硅少子寿命和间隙铁含量的影响。结果表明,直拉单晶硅在300~1050℃加热40 min,以50℃/s的速率快冷至室温会提高硅片的间隙铁含量,降低硅片的少子寿命;加热温度越高,快冷后硅片的间隙铁含量越高,少子寿命越低;直拉单晶硅片在900~1050℃加热,当以50℃/s的速率快冷至室温,90%以上的铁以沉淀形式存在,其余的铁以间隙态存在。直拉单晶硅片分别经800、900和1000℃加热40 min后在0.017~50℃/s的速率范围冷却,硅片间隙铁含量随冷却速率增加而增加,少子寿命随冷却速率增加而降低,加热温度越高,间隙铁含量上升的幅度越大,而少子寿命下降的幅度越大。

  4. HEAT RECUPERATION

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2011-01-01

    Full Text Available Heat recovery is an effective method of shortening specific energy consumption. new constructions of recuperators for heating and cupola furnaces have been designed and successfully introduced. two-stage recuperator with computer control providing blast heating up to 600 °C and reducing fuel consumption by 30% is of special interest.

  5. 荆州市基础测绘“十二五”规划编制研究%The Twelfth Five-Year Planning Research of the Basic Surveying and Mapping in Jingzhou

    Institute of Scientific and Technical Information of China (English)

    周勇; 胡冰; 彭李; 石莎

    2012-01-01

    基础测绘是国民经济和社会发展的一项长期的基础性工作。分析了荆州市基础测绘“十一五”期间取得的成绩和存在的问题,阐述了“十二五”期间经济社会发展对基础测绘的需求,提出了基础测绘的发展目标,明确了基础测绘的6项任务,制定了基础测绘重点项目规划,为地市级基础测绘“十二五”规划编制提供思路。%Basic surveying and mapping is a long-term basic and strategic work of the economic and social develop- ment. The paper analyzes the achievements and existing problems of Jingzhou basic surveying and mapping during the E- leventh Five-Year Plan period, describes the needs of economic and social development during the Twelfth Five-year Plan period. It proposes development goals of basic surveying and mapping, defines its six tasks and formulates key pro- jects plan. Ideas for establishing city basic surveying and mapping during the Twelfth Five-Year Plan are presented.

  6. Shakespeare revisité, entre fidélité et parodie : de La Nuit des Rois à Shake de Dan Jemmett Shakespeare Revisited, Between Fidelity and Parody: From Twelfth Night to Shake by Dan Jemmett

    Directory of Open Access Journals (Sweden)

    Isabelle Schwartz-Gastine

    2009-11-01

    Full Text Available William Shakespeare himself was a master of re-writing older material as he abundantly used this technique, which was totally justified at the Renaissance, to compose his poems or plays, from various sources whether literary (prose or verse, historical, or any other—and sometimes most unusual—background.The play I am considering in this paper is a very recent re-writing in English by Dan Jemmett (Peter Brook’s son-in-law, but performed in Marie-Paul Remo’s French translation at the Vidy Theatre in Lausanne during the 2001 season. It is called Shake, with a modest sub-title « around Twelfth Night », but which is indeed at the heart of the topic.Through the exploration of three themes: symmetry (of situations, of twin binarities, love’s misunderstanding, and music, I will argue that this comedy, whose title is a mix between the name of the Bard and the etymological meaning of the verb “to shake” as far as traditions are concerned, is faithful to the spirit (rather than the letter of the Shakespearean original in a very healthy comic vein.It is not worth wondering if the spectators fully understood the meaning of this comedy in which the four actors change roles all the time: their frequent bursts of laughter clearly showed that they enjoyed the spirit of the comedy, whether they knew Twelfth Night or not.

  7. Research on Affordable Housing Construction of Shanxi Province during the Twelfth Five-year Plan%山西省城镇"十二五"经济适用房研究

    Institute of Scientific and Technical Information of China (English)

    范恩海; 郑婷兰

    2011-01-01

    经济适用房是我国住房保障体系的重要组成部分,"十二五"期间应该加大经济适用房建设力度,以满足城镇中(低)收入家庭的基本住房需求.借助以及市场调查等统计资料,通过分析山西省商品住房市场价格、城镇新增居民家庭人均可支配收入等情况,预测得到经济适用房的保障线标准和保障比例,从而确定出"十二五"期间新增经济适用房的建设数量.%Affordable housing is an important part of China's housing security system. We should intensify affordable housing construction during the twelfth five-year to meet the basic housing demand of low-and middle-income families. With the help of statistical date which quoted from The Clorious 60 Years of Shanxi and market research statistical data through the analysis of the commodity housing market prices and per capita disposable income of urban increased households in Shanxi Province, predicts the security standards and security proportion of affordable housing, so as to determine the increased construction quantity of affordable housing during the twelfth five-year.

  8. Ignition delays, heats of combustion, and reaction rates of aluminum alkyl derivatives used as ignition and combustion enhancers for supersonic combustion

    Science.gov (United States)

    Ryan, Thomas W., III; Schwab, S. T.; Harlowe, W. W.

    1992-01-01

    The subject of this paper is the design of supersonic combustors which will be required in order to achieve the needed reaction rates in a reasonable sized combustor. A fuel additive approach, which is the focus of this research, is the use of pyrophorics to shorten the ignition delay time and to increase the energy density of the fuel. Pyrophoric organometallic compounds may also provide an ignition source and flame stabilization mechanism within the combustor, thus permitting use of hydrocarbon fuels in supersonic combustion systems. Triethylaluminum (TEA) and trimethylaluminum (TMA) were suggested for this application due to their high energy density and reactivity. The objective here is to provide comparative data for the ignition quality, the energy content, and the reaction rates of several different adducts of both TEA and TMA. The results of the experiments indicate the aluminum alkyls and their more stable derivatives reduce the ignition delay and total reaction time to JP-10 jet fuel. Furthermore, the temperature dependence of ignition delay and total reaction time of the blends of the adducts are significantly lower than in neat JP-10.

  9. Heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Craig, L.B.; Farma, A.J.

    1987-01-06

    This invention concerns a heat exchanger as used in a space heater, of the type in which hot exhaust gases transfer heat to water or the like flowing through a helical heat exchange coil. A significant improvement to the efficiency of the heat exchange occurring between the air and water is achieved by using a conduit for the water having external helical fluting such that the hot gases circulate along two paths, rather than only one. A preferred embodiment of such a heat exchanger includes a porous combustion element for producing radiant heat from a combustible gas, surrounded by a helical coil for effectively transferring the heat in the exhaust gas, flowing radially from the combustion element, to the water flowing through the coil. 4 figs.

  10. 重水堆停堆工况下单相自然循环流动与传热分析%Analysis on Flow Rate and Heat Transfer of Single-phase Natural Circulation Under Shutdown Condition for PHWR

    Institute of Scientific and Technical Information of China (English)

    苑景田; 佟立丽; 曹学武

    2014-01-01

    The single-phase natural circulation of the main heat transport system (HTS) for CANDU 6 under shutdown condition was analyzed by using RELAP5 code ,and the single-phase natural circulation mass flow rate model was developed .The comparison analysis of the Vijayan model and natural circulation models including the Chrichill-Chu model and McAdams model for RELAP5 was conducted ,respectively .The results show that a lower horizontal heat transfer coefficient is obtained by using Vijayan model than that by the McAdams model ,causing a slight higher cladding temperature .However , the vertical heat transfer coefficients from both models have no significant difference .%使用RELAP5程序建立CANDU 6型重水堆模型,对停堆工况下主热传输系统环路内的单相自然循环进行了分析研究,并推导出重水堆单相自然循环流量模型。对 Vijayan模型与 RELAP5程序的自然对流传热模型(Churchill-Chu和McAdams模型)进行比较计算,结果表明,Vijayan模型计算的水平壁面传热系数低于程序模型,造成包壳温度略高,而竖直壁面传热系数则无明显差别。

  11. Determination of phase transition points of ionic liquids by combination of thermal analysis and conductivity measurements at very low heating and cooling rates

    Energy Technology Data Exchange (ETDEWEB)

    Wachter, Philipp; Schreiner, Christian; Schweiger, Hans-Georg [Workgroup Electrochemistry and Electrolytes, Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitaetsstr. 31, D-93040 Regensburg (Germany); Gores, Heiner Jakob, E-mail: Heiner.Gores@Chemie.Uni-Regensburg.d [Workgroup Electrochemistry and Electrolytes, Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitaetsstr. 31, D-93040 Regensburg (Germany)

    2010-07-15

    The determination of phase transition points of nine different ionic liquids (ILs) was performed by thermal analysis with simultaneous recording of conductivity. Conductivity of electrolyte solutions and ILs drastically changes during phase transitions and thus is an additional and very sensitive indicator for measuring phase transition points. Evaluation of temperature-time functions and conductivity-time functions with our computer-coupled automated equipment enabled the determination of melting temperatures with high accuracy and reliability. This claim is based on large samples, low temperature change rates and by regularly repeated measurements, i.e. at least seven measurements per IL. The melting temperatures of 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate, 1-butyl-1-methylpyrrolidinium tris(penta-fluoroethyl)trifluorophosphate, and 1-methyl-3-propylimidazolium iodide were, to our knowledge, determined for the first time. The melting temperatures of the other 1-butyl-1-methylpyrrolidinium-, 1-ethyl-3-methylimidazolium-, 1-hexyl-3-methylimidazolium-, and trimethylsulfonium-based ILs showed either a very good accordance with values published in literature or were distinctly higher.

  12. 工质流量对ORC低温余热发电系统性能的影响%Effect of mass flow rate on performance of organic Rankine cycle for power generation system with low-temperature waste heat

    Institute of Scientific and Technical Information of China (English)

    王慧; 马新灵; 孟祥睿; 魏新利

    2015-01-01

    搭建了以自行研发的向心透平为膨胀机的ORC低温余热发电系统实验平台,研究了R123质量流量对循环系统的性能影响。结果表明:液压隔膜泵的温升和熵增均较小,所消耗的功率随流量的增加而增加。工质在蒸发器内的压降明显大于冷凝器内的压降,均随流量的增加而增加;向心透平的等熵效率随质量流量的增加先增加后减小,存在最佳流量0.215 kg·s−1使透平等熵效率达到最大值0.775;系统输出的电功率随流量的增加而增加,流量为0.283 kg·s−1时输出系统最大功率为2.009 kW;蒸发器的㶲损率占系统总㶲损率的比重最大,冷凝器次之,向心透平第三,在本实验最佳质量流量下,三者的㶲损率分别为62%、32%、6%。%An experimental prototype of organic Rankine cycle (ORC) was built for low-temperature waste heat power generation. With R123 as working fluid, heat transfer oil as the waste heat source, and radial inflow turbine as expander, a series of tests were carried out by adjusting the R123 mass flow rate to evaluate the performance of apparatus and system. The temperature rise and entropy increase of hydraulic diaphragm pump were lower, and consumed power increased with the mass flow rate. The pressure drop in the evaporator was greater than that in the condenser, and both increased with the mass flow rate of R123. The isentropic efficiency of the radial inflow turbine increased first and then decreased with the increase of R123 flow rate, with the maximum value of 0.775 kg·s−1 and the optimum value of 0.215 kg·s−1. The system output power increased monotonously to 2.009 kW as the flow rate of R123 increased to 0.283 kg·s−1. Exergy destruction rate of evaporator was the largest parts in total exergy destruction rate, followed by condenser and radial inflow turbine, about 62%, 32% and 6%, respectively, under the optimum condition.

  13. 46 CFR 56.85-5 - Heating and cooling method.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Heating and cooling method. 56.85-5 Section 56.85-5... APPURTENANCES Heat Treatment of Welds § 56.85-5 Heating and cooling method. Heat treatment may be accomplished by a suitable heating method that will provide the desired heating and cooling rates, the...

  14. Aquatic Exercise and Heat-Related Injuries.

    Science.gov (United States)

    Sova, Ruth

    1991-01-01

    Heat-related injuries in aquatics classes are possible, though 100 percent preventable. The article discusses heat-related syndromes; how bodies generate and dissipate heat; how elevated heart rates that burn calories differ from those that dissipate heat; and modification of exercise intensity to provide calorie-burning workouts without…

  15. 檫树、米槠、木荷板材燃烧热释放率研究%Study on Burning Heat Release Rate of Sassafras tzumu, Castanopsis Carlesii, Schima Superba Lumber

    Institute of Scientific and Technical Information of China (English)

    黄晓东; 刘雁; 刘武

    2001-01-01

    In order to select qualified fire retardant lumber, the burning heat release rate of Sassafras tzu mu, Castanopsis Carlesii and Schima Superba lumber was measured with HRR3 system produced by AT LAS company, and the fire-retardancy of lumber of the species was appraised according to Airworthiness Approval Tag US Department of Transportation Federal Aviation Administation.%采用美国阿特拉斯公司生产的HRR3热释放率系统,按照美国航空局(FAA)的标准要求测试檫树、米槠、木荷板材燃烧的热释放率(HRR),为阻燃板材选择合格基材。

  16. Investigation of material removal rate (MRR) and wire wear ratio (WWR) for alloy Ti6Al4 V exposed to heat treatment processing in WEDM and optimization of parameters using Grey relational analysis

    Energy Technology Data Exchange (ETDEWEB)

    Altug, Mehmet [Inonu Univ., Malatya (Turkey). Dept. of Machine and Metal Technologies

    2016-11-01

    The study examines the changes of the microstructural, mechanical and conductivity characteristics of the titanium alloy Ti6Al4 V as a result of heat treatment using wire electrical discharge machining, and their effect on machinability. By means of optical microscopy and scanning electron microscopy (SEM), analyses have been performed to determine various characteristics and additionally, microhardness and conductivity measurements have been conducted. Material removal rate (MRR) and wire wear ratio (WWR) values have been determined by using L18 Taguchi test design. The microstructures of the samples have been changed by thermal procedures. Results have been obtained by using the Grey relational analysis (GRA) optimization technique to solve the maximum MRR and minimum WWR values. The best (highest) MRR value is obtained from sample E which was water quenched in dual phase processing. The microstructure of this sample is composed of primary α and α' phases. The best (lowest) WWR value is obtained from sample A.

  17. Analysis of Heart Rate Variability of Coronary Heart Disease Patients with Phlegm Heat Syndrome%冠心病痰热证患者心率变异性分析

    Institute of Scientific and Technical Information of China (English)

    齐连芬; 李川洁; 方业明; 刘晓洁; 李平; 王林海

    2012-01-01

    Objective To discuss the characteristics and clinical significance of cardiovascular autonomic nervous function changes through analysis of heart rate variability (HRV) of patients with coronary heart disease (CHD) and phlegm heat syndrome. Methods Seventy-nine patients were diagnosed as CHD by coronary angiography or myocardial infarction medical history. A group of 30 cases with phlegm heat syndrome and another group of 30 cases with blood stasis syndrome were selected from them. Then the time domain parameters of HRV in Holter testing of the 2 groups were compared. Results The time domain parameters of phlegm heat syndrome group were less than that of blood stasis syndrome group obviously (PSDNN>50 ms) was higher than that of the blood stasis syndrome group obviously (P<0.01). Conclusion For patients with CHD with phlegm heat syndrome, obviously decreasing of HRV time domain parameters suggests serious damage of autonomic nervous, and indicates high risk of sudden death in cardiovascular events.%目的 通过对痰热证冠心病患者的心率变异性(HRV)进行分析,探讨此证型患者的心脏自主神经功能改变特点及临床意义.方法收集经冠状动脉造影或明确心肌梗死病史等确诊为冠心病的患者79例,辨证为痰热证组30例,血瘀证组30例,2组均进行动态心电图检查,分析HRV时域参数.结果 痰热证组HRV时域参数明显低于血瘀证组(P<0.01).痰热证组HRV参数SDNN在不同降低程度(SDNN≤50 ms、100 ms>SDNN>50 ms)的发生率明显高于血瘀证组(P<0.01).结论 冠心病痰热证患者HRV时域指标降低明显,提示自主神经损害严重,预示心血管事件中猝死风险增加.

  18. “十二五”末江西增产“50亿斤粮”的出路与对策建议%Solutions and Countermeasures for "Increasing Grain Products by 2.5 Billion Kilogram" of Jiangxi in "Twelfth Five - years"

    Institute of Scientific and Technical Information of China (English)

    杨正威; 陈红萍; 颜龙安; 陆朝梁; 熊大建; 龙丘陵

    2012-01-01

    江西省“十二五”规划纲要中提出“十二五”期间我省“新增粮食产量50亿斤”,以策应国家“十二五”“增加1000亿斤粮食”的目标.本文分析了当前江西粮食综合生产能力及存在的问题、粮食生产中有利条件和面临的挑战,提出了“十二五”末江西增产“50亿斤粮”的出路与对策建议.%In order to support the country's target of "increasing the grain products by 50 billion kilogram" in "Twelfth Five -years" , the "Twelfth Five - years" planning program of Jiangxi province put forward "increasing the grain products by 2.5 billion kilogram" in "Twelfth Five-years". This paper analyzed the overall grain production capability, the existing problems, advantages and faced challenges in grain production of Jiangxi at present, and put forward the solutions and countermeasures for "increasing the grain products by 2.5 billion kilogram" of Jiangxi in "Twelfth Five -years".

  19. Ecological performance of a generalized irreversible Carnot heat engine with complex heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Fengrui Sun

    2011-01-01

    Full Text Available The optimal ecological performance of a generalized irreversible Carnot heat engine with the losses of heat-resistance, heat leakage and internal irreversibility, in which the transfer between the working fluid and the heat reservoirs obeys a complex heat transfer law, including generalized convective heat transfer law and generalized radiative heat transfer law is derived by taking an ecological optimization criterion as the objective, which consists of maximizing a function representing the best compromise between the power and entropy production rate of the heat engine. The effects of heat transfer laws and various loss terms are analyzed. The obtained results include those obtained in many literatures.

  20. Carbon nanostructured surfaces for enhanced heat transport

    NARCIS (Netherlands)

    Taha, T.J.

    2015-01-01

    The advancement of high performance thermal systems has stimulated interest in methods to improve heat transfer rates. Considerable efforts have been made to increase heat transfer rates by implementing passive convective heat transfer enhancement methods that require no direct consumption of extern

  1. Carbon nanostructured surfaces for enhanced heat transport

    NARCIS (Netherlands)

    Taha, Taha Jibril

    2015-01-01

    The advancement of high performance thermal systems has stimulated interest in methods to improve heat transfer rates. Considerable efforts have been made to increase heat transfer rates by implementing passive convective heat transfer enhancement methods that require no direct consumption of extern

  2. Carbon nanostructured surfaces for enhanced heat transport

    NARCIS (Netherlands)

    Taha, T.J.

    2015-01-01

    The advancement of high performance thermal systems has stimulated interest in methods to improve heat transfer rates. Considerable efforts have been made to increase heat transfer rates by implementing passive convective heat transfer enhancement methods that require no direct consumption of

  3. Digitized Heat Transfer

    Science.gov (United States)

    Mohseni, Kamran; Young, Patrick

    2007-11-01

    This presentation presents theoretical and numerical results describing digitized heat transfer (DHT), an active thermal management technique for high-power electronics and integrated micro systems. In digitized heat transfer discrete droplets are employed. The internal flow inside a discrete droplet is dominated by internal circulation imposed by the boundaries. This internal circulation imposes a new timescale for recirculating cold liquid from the middle of the droplet to the boundary. This internal circulation produces periodic oscillation in the overall convective heat transfer rate. Numerical simulations are presented for heat transfer in the droplet for both constant temperature and flux boundary conditions. The effectiveness of DHT for managing both localized temperature spikes and steady state cooling is demonstrated, identifying key parameters for optimization of the DHT method.

  4. Theoretical and experimental research on heat transfer performance of the semi-open heat pipe

    Institute of Scientific and Technical Information of China (English)

    Hua ZHU; Bo ZHUANG; Jin-jun TAN; Rong-hua HONG

    2008-01-01

    This paper focuses on the heat transfer performance of semi-open heat pipe which is a new type of heat pipe. After analyzing its condensation heat transfer mechanisms theoretically, several semi-open heat pipes in different length ratios and upper hole diameters are studied experimentally and compared with the same dimensions closed heat pipes. Experimental results show that the heat transfer performance of semi-open heat pipe becomes better by increasing heat transfer rate. At the first transitional point, the heat transfer performance of semi-open heat pipe approaches the level of the closed heat pipe. It is suitable to choose upper small hole about 1 mm in diameter and length ratio larger than 0.6 for the semi-open heat pipe.

  5. Realiability Of Heat Supply Subsystem

    Directory of Open Access Journals (Sweden)

    Babiarz Bożena

    2015-11-01

    Full Text Available The article presents the reliability analysis of subsystem of heat supply in the example of 47 thousand inhabitants’ city. The analysis was made on the basis of operational data made available by the Municipal Heating Company, between the years 2001 ÷ 2012. To describe the quantitative reliability of heat supply subsystem reliability indicators are used. Main times between failure and unitary failure rates including the month of their occurrence, type and diameter of the heating network, thermal power region were working out. Knowing the characteristics of the time to repair for the heating network, the reliability of heat supply subsystem for different thermal power region, considering the district heating system configuration can be determined.

  6. “十二五”期间陕西人身保险市场需求变化研究%Analysis of the Changes in Life Insurance Market Demand of Shaanxi Province During the Twelfth Five-Year

    Institute of Scientific and Technical Information of China (English)

    杨馥; 刘珺

    2012-01-01

    The development of life insurance market in Shaanxi Province will be promoted by the substainable development of Shaanxi's economy and society during the Twelfth Five-Year.The demand of life insurance is key index of the development of lif insurance market.The demand of life insurance market is measured by life insurance premiums in Shaanxi.Based on the data in 1990-2009,this paper provides positive analysis on the demand of life insurance market in Shaanxi by cointegration and logarithm function-model.Following the results,it predicts the trends of life insurance market demands in Shanxi during the Twelfth Five-Year plan,to provide theory basis for life insurance market planning.%"十二五"期间,陕西省经济的持续发展为陕西省人身保险市场的发展提供了有利契机。人身保险需求是度量人身保险市场发展状况的重要指标。文章以陕西省人身保险保费收入作为衡量人身保险市场需求的变量,参考保险密度和保险深度等指标,选取1990—2009年的相关数据,采用协整检验,利用自然对数模型对陕西省人身保险市场需求进行实证分析,并据此对"十二五"期间陕西省人身保险市场需求变化趋势进行预测,旨在为陕西省人身保险业规划提供理论依据。

  7. Comparative analysis of the heat transfer rates in constant (CAV) and variable (VAV) volumes type multi zone acclimation system operating in hot and humid climate; Analise comparativa das taxas transferencia de calor em sistemas de climatizacao do tipo volume de ar constante (CAV) e volume de ar variavel (VAV) multizona operando em clima quente e umido

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Cesar A.G.; Correa, Jorge E. [Para Univ., Belem (Brazil). Centro Tecnologico. Dept. de Engenharia Mecanica]. E-mails: gsantos@ufpa.br; jecorrea@amazon.com.br

    2000-07-01

    This work performs a comparative analysis among the constant and variable air volume multi zones acclimation systems, used for provide the thermal comfort in buildings. The work used the simulation HVAC2KIT computer program. The results of sensible and latent heats transfer rates on the cooling and dehumidification, inflating fan capacity, and heat transfer on the final heating condenser were obtained and analysed for the climate conditions of the Brazilian city of Belem from Para State, presenting hot and humid climate during all the year.

  8. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1994-01-01

    It is approximately 10 years since the Third Edition of Heat Pipes was published and the text is now established as the standard work on the subject. This new edition has been extensively updated, with revisions to most chapters. The introduction of new working fluids and extended life test data have been taken into account in chapter 3. A number of new types of heat pipes have become popular, and others have proved less effective. This is reflected in the contents of chapter 5. Heat pipes are employed in a wide range of applications, including electronics cooling, diecasting and injection mo

  9. Magnetar heating

    CERN Document Server

    Beloborodov, Andrei M

    2016-01-01

    We examine four candidate mechanisms that could explain the high surface temperatures of magnetars. (1) Heat flux from the liquid core heated by ambipolar diffusion. It could sustain the observed surface luminosity $L_s\\approx 10^{35}$ erg s$^{-1}$ if core heating offsets neutrino cooling at a temperature $T_{\\rm core}>6\\times 10^8$ K. This scenario is viable if the core magnetic field exceeds $10^{16}$ G, the magnetar has mass $M10^{16}$ G varying on a 100 meter scale could provide $L_s\\approx 10^{35}$ erg s$^{-1}$. (4) Bombardment of the stellar surface by particles accelerated in the magnetosphere. This mechanism produces hot spots on magnetars. Observations of transient magnetars show evidence for external heating.

  10. Heat emergencies

    Science.gov (United States)

    ... death. The early symptoms of heat cramps include: Muscle cramps and pains that most often occur in the ... do if salt beverages are not available. For muscle cramps , give beverages as noted above and massage affected ...

  11. Differences in the Ovine HSP90AA1 Gene Expression Rates Caused by Two Linked Polymorphisms at Its Promoter Affect Rams Sperm DNA Fragmentation under Environmental Heat Stress Conditions

    Science.gov (United States)

    González, Carmen; Pérez-Guzmán, M. Dolores; Garde, J. Julián; García-Álvarez, Olga; Maroto-Morales, Alejandro; Calvo, Jorge H.; Serrano, M. Magdalena

    2015-01-01

    Heat shock (HS) is one of the best-studied exogenous cellular stresses. Almost all tissues, cell types, metabolic pathways and biochemical reactions are affected in greater or lesser extent by HS. However, there are some especially thermo sensible cellular types such as the mammalian male germ cells. The present study examined the role of three INDELs in conjunction with the -660G/C polymorphism located at the HSP90AA1 promoter region over the gene expression rate under HS. Specially, the -668insC INDEL, which is very close to the -660G/C transversion, is a good candidate to be implied in the transcriptional regulation of the gene by itself or in a cooperative way with this SNP. Animals carrying the genotype II-668 showed higher transcription rates than those with ID-668 (FC = 3.07) and DD-668 (FC = 3.40) genotypes for samples collected under HS. A linkage between gene expression and sperm DNA fragmentation was also found. When HS conditions were present along or in some stages of the spermatogenesis, alternative genotypes of the -668insC and -660G/C mutations are involved in the effect of HS over sperm DNA fragmentation. Thus, unfavorable genotypes in terms of gene expression induction (ID-668GC-660 and DD-668GG-660) do not produce enough mRNA (stored as messenger ribonucleoprotein particles) and Hsp90α protein to cope with future thermal stress which might occur in posterior stages when transcriptional activity is reduced and cell types and molecular processes are more sensible to heat (spermatocytes in pachytene and spermatids protamination). This would result in the impairment of DNA packaging and the consequent commitment of the events occurring shortly after fertilization and during embryonic development. In the short-term, the assessment of the relationship between sperm DNA fragmentation sensitivity and ram’s fertility will be of interest to a better understanding of the mechanisms of response to HS and its consequences on animal production and

  12. Differences in the ovine HSP90AA1 gene expression rates caused by two linked polymorphisms at its promoter affect rams sperm DNA fragmentation under environmental heat stress conditions.

    Science.gov (United States)

    Salces-Ortiz, Judit; Ramón, Manuel; González, Carmen; Pérez-Guzmán, M Dolores; Garde, J Julián; García-Álvarez, Olga; Maroto-Morales, Alejandro; Calvo, Jorge H; Serrano, M Magdalena

    2015-01-01

    Heat shock (HS) is one of the best-studied exogenous cellular stresses. Almost all tissues, cell types, metabolic pathways and biochemical reactions are affected in greater or lesser extent by HS. However, there are some especially thermo sensible cellular types such as the mammalian male germ cells. The present study examined the role of three INDELs in conjunction with the -660G/C polymorphism located at the HSP90AA1 promoter region over the gene expression rate under HS. Specially, the -668insC INDEL, which is very close to the -660G/C transversion, is a good candidate to be implied in the transcriptional regulation of the gene by itself or in a cooperative way with this SNP. Animals carrying the genotype II-668 showed higher transcription rates than those with ID-668 (FC = 3.07) and DD-668 (FC = 3.40) genotypes for samples collected under HS. A linkage between gene expression and sperm DNA fragmentation was also found. When HS conditions were present along or in some stages of the spermatogenesis, alternative genotypes of the -668insC and -660G/C mutations are involved in the effect of HS over sperm DNA fragmentation. Thus, unfavorable genotypes in terms of gene expression induction (ID-668GC-660 and DD-668GG-660) do not produce enough mRNA (stored as messenger ribonucleoprotein particles) and Hsp90α protein to cope with future thermal stress which might occur in posterior stages when transcriptional activity is reduced and cell types and molecular processes are more sensible to heat (spermatocytes in pachytene and spermatids protamination). This would result in the impairment of DNA packaging and the consequent commitment of the events occurring shortly after fertilization and during embryonic development. In the short-term, the assessment of the relationship between sperm DNA fragmentation sensitivity and ram's fertility will be of interest to a better understanding of the mechanisms of response to HS and its consequences on animal production and

  13. Indoor temperatures for calculating room heat loss and heating capacity of radiant heating systems combined with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Olesen, Bjarne W.; Fang, Lei;

    2016-01-01

    system were determined according to the principle of heat transfer. A model to predict indoor temperatures in the room was proposed, and it was determined that the predicted indoor temperatures agreed well with the measured data. Qualitative analyses of the effects of heated surface temperature and air...... change rates on the indoor temperatures were performed using the proposed model. When heated surface temperatures and air change rates were from 21.0 to 29.0 degrees C and from 0.5 to 4.0 h-1, the indoor temperatures for calculating the transmission heat loss and ventilation heat loss were between 20.......8% for calculating the transmission heat loss and ventilation heat loss, respectively, and between 16.0% and 17.4% for calculating the heating capacity of the hybrid system. Due to large relative calculation errors, it is necessary to consider the effect of heated surface and cool supply air on indoor temperatures...

  14. Analysis of the heat transfer in double and triple concentric tube heat exchangers

    Science.gov (United States)

    Rădulescu, S.; Negoiţă, L. I.; Onuţu, I.

    2016-08-01

    The tubular heat exchangers (shell and tube heat exchangers and concentric tube heat exchangers) represent an important category of equipment in the petroleum refineries and are used for heating, pre-heating, cooling, condensation and evaporation purposes. The paper presents results of analysis of the heat transfer to cool a petroleum product in two types of concentric tube heat exchangers: double and triple concentric tube heat exchangers. The cooling agent is water. The triple concentric tube heat exchanger is a modified constructive version of double concentric tube heat exchanger by adding an intermediate tube. This intermediate tube improves the heat transfer by increasing the heat area per unit length. The analysis of the heat transfer is made using experimental data obtained during the tests in a double and triple concentric tube heat exchanger. The flow rates of fluids, inlet and outlet temperatures of water and petroleum product are used in determining the performance of both heat exchangers. Principally, for both apparatus are calculated the overall heat transfer coefficients and the heat exchange surfaces. The presented results shows that triple concentric tube heat exchangers provide better heat transfer efficiencies compared to the double concentric tube heat exchangers.

  15. Selection of Rational Heat Transfer Intensifiers in the Heat Exchanger

    Directory of Open Access Journals (Sweden)

    S. A. Burtsev

    2016-01-01

    Full Text Available The paper considers the applicability of different types of heat transfer intensifiers in the heat exchange equipment. A review of the experimental and numerical works devoted to the intensification of the dimpled surface, surfaces with pins and internally ribbed surface were presented and data on the thermal-hydraulic characteristics of these surfaces were given. We obtained variation of thermal-hydraulic efficiency criteria for 4 different objective functions and 15 options for the intensification of heat transfer. This makes it possible to evaluate the advantages of the various heat transfer intensifiers. These equations show influence of thermal and hydraulic characteristics of the heat transfer intensifiers (the values of the relative heat transfer and drag coefficients on the basic parameters of the shell-and-tube heat exchanger: the number and length of the tubes, the volume of the heat exchanger matrix, the coolant velocity in the heat exchanger matrix, coolant flow rate, power to pump coolant (or pressure drop, the amount of heat transferred, as well as the average logarithmic temperature difference. The paper gives an example to compare two promising heat transfer intensifiers in the tubes and shows that choosing the required efficiency criterion to search for optimal heat exchanger geometry is of importance. Analysis is performed to show that a dimpled surface will improve the effectiveness of the heat exchanger despite the relatively small value of the heat transfer intensification, while a significant increase in drag of other heat transfer enhancers negatively affects their thermalhydraulic efficiency. For example, when comparing the target functions of reducing the heat exchanger volume, the data suggest that application of dimpled surfaces in various fields of technology is possible. But there are also certain surfaces that can reduce the parameters of a heat exchanger. It is shown that further work development should be aimed at

  16. A heat transfer model of a horizontal ground heat exchanger

    Science.gov (United States)

    Mironov, R. E.; Shtern, Yu. I.; Shtern, M. Yu.; Rogachev, M. S.

    2016-04-01

    Ground-source heat pumps are gaining popularity in Eastern Europe, especially those which are using the horizontal ground heat exchanger (GHX). Due to the difficulty of accessing GHX after the installation, materials and the quality of the installation must satisfy the very high requirements. An inaccurate calculation of GHX can be the reason of a scarcity of heat power in a crucial moment. So far, there isn't any appropriate mathematical description of the horizontal GHX which takes into account the mutual influence of GHX pipes on each other. To solve this problem we used the temperature wave approach. As a result, a mathematical model which describes the dependence of the heat transfer rate per unit length of the horizontal GHX pipe on the thermal properties of soil, operating time of GHX and the distance between pipes was obtained. Using this model, heat transfer rates per unit length of a horizontal GHX were plotted as functions of the distance between pipes and operating time. The modeling shows that heat transfer rates decreases rapidly with the distance between pipes lower then 2 meters. After the launch of heat pump, heat power of GHX is reduced during the first 20 - 30 days and get steady after that. The obtained results correlate with experimental data. Therefore the proposed mathematical model can be used to design a horizontal GHX with the optimal characteristics, and predict its capability during operation.

  17. Heat transfer

    CERN Document Server

    Holman, J P

    2010-01-01

    As one of the most popular heat transfer texts, Jack Holman's "Heat Transfer" is noted for its clarity, accessible approach, and inclusion of many examples and problem sets. The new tenth edition retains the straight-forward, to-the-point writing style while covering both analytical and empirical approaches to the subject. Throughout the book, emphasis is placed on physical understanding while, at the same time, relying on meaningful experimental data in those situations that do not permit a simple analytical solution. New examples and templates provide students with updated resources for computer-numerical solutions.

  18. Heat pipe turbine vane cooling

    Energy Technology Data Exchange (ETDEWEB)

    Langston, L.; Faghri, A. [Univ. of Connecticut, Storrs, CT (United States)

    1995-10-01

    The applicability of using heat pipe principles to cool gas turbine vanes is addressed in this beginning program. This innovative concept involves fitting out the vane interior as a heat pipe and extending the vane into an adjacent heat sink, thus transferring the vane incident heat transfer through the heat pipe to heat sink. This design provides an extremely high heat transfer rate and an uniform temperature along the vane due to the internal change of phase of the heat pipe working fluid. Furthermore, this technology can also eliminate hot spots at the vane leading and trailing edges and increase the vane life by preventing thermal fatigue cracking. There is also the possibility of requiring no bleed air from the compressor, and therefore eliminating engine performance losses resulting from the diversion of compressor discharge air. Significant improvement in gas turbine performance can be achieved by using heat pipe technology in place of conventional air cooled vanes. A detailed numerical analysis of a heat pipe vane will be made and an experimental model will be designed in the first year of this new program.

  19. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... for signs of heat stroke or exhaustion. Heat Stroke and Exhaustion Symptoms of early heat exhaustion symptoms ... heavy sweating; nausea; and giddiness. Symptoms of heat stroke (late stage of heat illness) include flushed, hot, ...

  20. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... for signs of heat stroke or exhaustion. Heat Stroke and Exhaustion Symptoms of early heat exhaustion symptoms ... heavy sweating; nausea; and giddiness. Symptoms of heat stroke (late stage of heat illness) include flushed, hot, ...

  1. HEAT TRANSFER ANALYSIS OF HEAT GENERATING WIRE USING FINITE ELEMENT METHOD

    OpenAIRE

    Dipak J. Parmar; Bhargav M. Chavda

    2000-01-01

    This paper describes the numerical results of the heat transfer from heat generating wire at different conditions by finite element method. The parametric effects on heat transfer were investigated. The varied parameters included ambient conditions, as well as the shape of the cross-section. The numerical results show that the type of the medium where the heat generating wire immerges has strong effects on the heatdissipation rate. As the size of the diameter the heat dis...

  2. Infrared heating

    Science.gov (United States)

    IR heating was first industrially used in the 1930s for automotive curing applications and rapidly became a widely applied technology in the manufacturing industry. Contrarily, a slower pace in the development of IR technologies for processing foods and agricultural products was observed, due to lim...

  3. Least dissipation principle of heat transport potential capacity and its application in heat conduction optimization

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In the viewpoint of heat transfer, heat transport potential capacity and its dissipation are defined based on the essence of heat transport phenomenon. Respectively, their physical meanings are the overall heat transfer capabilityand the dissipation rate of the heat transfer capacity. Then the least dissipation principle of heat transport potential capacity is presented to enhance the heat conduction efficiency in the heat conduction optimization. The principle is,for a conduction process with the constant integral of the thermal conductivityover the region, the optimal distribution of thermal conductivity, which corresponds to the highest heat conduction efficiency, is characterized by the least dissipation of heat transport potential capacity. Finally the principle is applied to some cases in heat conduction optimization.

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

    Science.gov (United States)

    Tiari, Saeed; Mahdavi, Mahboobe; Qiu, Songgang

    2016-11-01

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

  5. Exergy-Economic Criteria for Evaluating Heat Exchanger Performance

    Institute of Scientific and Technical Information of China (English)

    Wu Shuangying; Li Yourong

    2001-01-01

    Based on the exergy-economic analysis of heat exchanger heat transfer and flow process, two new exergyeconomic criteria which are defined as the total costs per unit heat transfer rate ηt t for heat transfer exchanger and the net profit per unit heat recovery rate ηr for heat recovery exchanger respectively are put forward.Furthermore, the application of criteria is illustrated by the evaluation of down-flow, counter-flow and cross-flow heat exchangers performance. The methods employed and results presented in this paper can serve as a guide for the performance evaluation of heat exchangers.

  6. Effects on annual cost of solar/air-heat utilization system of carbon tax and interest rate for a residential house; Jutakuyo taiyo/taikinetsu riyo system no nenkan keihi ni oyobosu tansozei kinri no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Q.; Kenmoku, Y.; Sakakibara, T. [Toyohashi University of Technology, Aichi (Japan); Nakagawa, S. [Maizuru National College of Technology, Kyoto (Japan); Kawamoto, T. [Shizuoka University, Shizuoka (Japan). Faculty of Engineering

    1996-10-27

    In recent years, a system has been proposed that utilizes river heat, air-heat, exhaust heat from a cooler, etc., in addition to natural energy for the heat pump. With the introduction of such system, the amount of energy used and that of CO2 exhaust will be greatly reduced, but annual expenses will be increased as it stands. In order to improve the cost efficiency of the system, a proposal has been made for the introduction of an economic policy such as the carbon tax and a low interest financing system. With these matters in the background, the subject study predicts the production of solar cells in the future and, on the basis of this production, determines the price, conversion efficiency and equipment energy of solar cells in the future. Using these values and taking into consideration the introduction of the carbon tax and the low interest financing system, the optimum area was determined for solar cells and heat concentrators in a future residential solar/air-heat energy system. The carbon tax, being imposed on all CO2 discharges, had a large effect. Moreover, as the tax increased, annual expenses decreased for the solar/air-heat system. 3 refs., 6 figs.

  7. Waste Heat to Power Market Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Elson, Amelia [ICF International, Fairfax, VA (United States); Tidball, Rick [ICF International, Fairfax, VA (United States); Hampson, Anne [ICF International, Fairfax, VA (United States)

    2015-03-01

    Waste heat to power (WHP) is the process of capturing heat discarded by an existing process and using that heat to generate electricity. In the industrial sector, waste heat streams are generated by kilns, furnaces, ovens, turbines, engines, and other equipment. In addition to processes at industrial plants, waste heat streams suitable for WHP are generated at field locations, including landfills, compressor stations, and mining sites. Waste heat streams are also produced in the residential and commercial sectors, but compared to industrial sites these waste heat streams typically have lower temperatures and much lower volumetric flow rates. The economic feasibility for WHP declines as the temperature and flow rate decline, and most WHP technologies are therefore applied in industrial markets where waste heat stream characteristics are more favorable. This report provides an assessment of the potential market for WHP in the industrial sector in the United States.

  8. Effect of Thermo-treatment on Heating Dimensional Change Rate of Formed PVC Composite Wood Floor%热处理对PVC发泡复合地板加热尺寸变化率的影响

    Institute of Scientific and Technical Information of China (English)

    王洪艳; 汤文进; 徐瑞英; 方庆华; 鲍建华; 袁少飞; 李琴; 杜官本

    2014-01-01

    The formed PVC composite wood floor was treated by thermo-treatment,the heating dimensional change rate, surface morphology and thermal properties of formed PVC material treated/untreated were analyzed. The results show that the dimensional changes can be reduced evidently after the thermo-treatment because of the changes in the surface structure;the processing temperature and processing time are two important factors,the processing temperature is more significant than the processing temperature for the formed PVC composite wood floor. The dimensional changes of the formed PVC composite wood floor reduce evidently when the processing temperature is above 80℃. The rate of dimensional changes can be reduced to about 0.2%which is less than the government standard(GB/T 11982.1–2005) requirement 0.4%.%对热处理前后聚氯乙烯(PVC)发泡复合地板的加热尺寸变化率进行了研究,并对处理前后PVC发泡复合地板基材(PVC发泡材料)的表面形态及相关热性能进行了分析。结果表明,热处理后PVC复合地板基材表面泡孔结构发生明显变化,能降低复合地板的加热尺寸变化率;热处理温度和时间是两个比较重要的因素,温度较时间影响显著,温度在80℃以上对减小PVC发泡复合地板的加热尺寸变化率有明显的效果;试验中采用140℃处理1 min时, PVC发泡复合地板的加热尺寸变化率均能达到0.2%左右(低于GB/T 11982.1–2005要求的0.4%)。

  9. 瞬发和缓发γ射线对堆内构件释热率影响的研究%Study on the influence of prompt fission γ-ray and delayed γ-ray on reactor internals heating rate

    Institute of Scientific and Technical Information of China (English)

    苏耿华; 石秀安; 蔡德昌; 李雷

    2012-01-01

    To improve the accuracy of the calculated reactor internals heating rate in the design of nuclear power plants, this paper studied the contribution of prompt fission γ to the reactor internals heating rate based on the original method of MCNP external neutron source model. The results revealed that the reactor internals heating rate increased by 9% ~38% with prompt fission γ taken into account and the internals nearer to the core had a lager increment. In addition, it is believed after analysis that the contribution of the delayed γ on reactor internals heating rate is similar to the prompt fission γ. Therefore, when calculating reactor internals heating rate, in addition to the neutron source and neutron capture γ, prompt fission γ and delayed γ should also be considered.%为提高核电设计中反应堆堆内构件释热率计算的准确性,本文在原来MCNP外中子源模型计算方法的基础上,计算分析瞬发裂变γ对堆内构件释热率的贡献.计算结果显示,考虑瞬发裂变γ使得堆内构件的释热率增加9%~38%,离堆芯越近的堆内构件的增加值越大.另外,分析认为缓发γ对堆内构件释热率的贡献与瞬发裂变γ相当.因而反应堆堆内构件释热率计算中除了考虑中子及中子俘获所生γ的贡献,还应该考虑瞬发裂变γ和缓发γ的贡献.

  10. Heat Related Illnesses

    Institute of Scientific and Technical Information of China (English)

    Robert Carter III; Samuel N. Cheuvront; Michael N. Sawka

    2007-01-01

    @@ KEY POINTS · Heat illnesses range in severity from mild (heat rash, heat syncope, cramps) to serious (heat exhaustion, heat injury, heat stroke). · Although heat illness can occur in anyone, an increased risk is associated with a variety of environmental factors, personal characteristics,health conditions, and medications.

  11. Geothermal district heating systems

    Science.gov (United States)

    Budney, G. S.; Childs, F.

    1982-06-01

    Ten district heating demonstration projects and their present status are described. The projects are Klamath County YMCA, Susanville District Heating, Klamath Falls District Heating, Reno Salem Plaza Condominium, El Centro Community Center Heating/Cooling, Haakon School and Business District Heating, St. Mary's Hospital, Diamond Ring Ranch, Pagosa Springs District Heating, and Boise District Heating.

  12. Carburos de Cobalto-Molibdeno soportados sobre carbón activado: efecto del método de síntesis, velocidad de calentamiento, tipo de precursor de cobalto y agente presulfurante en la hidrodesulfuración de tiofeno/Activated carbon supported cobalt-molybdenum carbides: effect of the synthesis method, heating rate, type of cobalt precursor and presulfiding agent on thiophene hydrodesulfurization

    National Research Council Canada - National Science Library

    Esneyder Puello-Polo; Mónica V Ayala; Joaquín L Brito

    2014-01-01

      This work studied the effect of the presulfiding agent, type of precursor, synthesis method and heating rate in the hydrodesulfurization of thiophene over activated carbon supported cobalt-molybdenum carbides...

  13. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa;

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change...... material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the presence of crystallization is studied experimentally. Fluid flow and heat transfer in the PCM module...... are theoretically investigated by Computational Fluid Dynamics (CFD) calculations. The heat transfer rates between the PCM storage and the heating fluid/cooling fluid in the plate heat exchangers are determined. The CFD calculated temperatures are compared to measured temperatures. Based on the studies...

  14. Optimizing Sustainable Geothermal Heat Extraction

    Science.gov (United States)

    Patel, Iti; Bielicki, Jeffrey; Buscheck, Thomas

    2016-04-01

    Geothermal heat, though renewable, can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal. As such, the sustainability of a geothermal resource is typically viewed as preserving the energy of the reservoir by weighing heat extraction against renewability. But heat that is extracted from a geothermal reservoir is used to provide a service to society and an economic gain to the provider of that service. For heat extraction used for market commodities, sustainability entails balancing the rate at which the reservoir temperature renews with the rate at which heat is extracted and converted into economic profit. We present a model for managing geothermal resources that combines simulations of geothermal reservoir performance with natural resource economics in order to develop optimal heat mining strategies. Similar optimal control approaches have been developed for managing other renewable resources, like fisheries and forests. We used the Non-isothermal Unsaturated-saturated Flow and Transport (NUFT) model to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are integrated into the optimization model to determine the extraction path over time that maximizes the net present profit given the performance of the geothermal resource. Results suggest that the discount rate that is used to calculate the net present value of economic gain is a major determinant of the optimal extraction path, particularly for shallower and cooler reservoirs, where the regeneration of energy due to the natural geothermal heat flux is a smaller percentage of the amount of energy that is extracted from the reservoir.

  15. Finite time exergoeconomic performance optimization for an irreversible universal steady flow variable-temperature heat reservoir heat pump cycle model

    Directory of Open Access Journals (Sweden)

    Huijun Feng, Lingen Chen, Fengrui Sun

    2010-11-01

    Full Text Available An irreversible universal steady flow heat pump cycle model with variable-temperature heat reservoirs and the losses of heat-resistance and internal irreversibility is established by using the theory of finite time thermodynamics. The universal heat pump cycle model consists of two heat-absorbing branches, two heat-releasing branches and two adiabatic branches. Expressions of heating load, coefficient of performance (COP and profit rate of the universal heat pump cycle model are derived, respectively. By means of numerical calculations, heat conductance distributions between hot- and cold-side heat exchangers are optimized by taking the maximum profit rate as objective. There exist an optimal heat conductance distribution and an optimal thermal capacity rate matching between the working fluid and heat reservoirs which lead to a double maximum profit rate. The effects of internal irreversibility, total heat exchanger inventory, thermal capacity rate of the working fluid and heat capacity ratio of the heat reservoirs on the optimal finite time exergoeconomic performance of the cycle are discussed in detail. The results obtained herein include the optimal finite time exergoeconomic performances of endoreversible and irreversible, constant- and variable-temperature heat reservoir Brayton, Otto, Diesel, Atkinson, Dual, Miller and Carnot heat pump cycles.

  16. MODEL OF HEAT SIMULATOR FOR DATA CENTERS

    Directory of Open Access Journals (Sweden)

    Jan Novotný

    2016-08-01

    Full Text Available The aim of this paper is to present a design and a development of a heat simulator, which will be used for a flow research in data centers. The designed heat simulator is based on an ideological basis of four-processor 1U Supermicro server. The designed heat simulator enables to control the flow and heat output within the range of 10–100 %. The paper covers also the results of testing measurements of mass flow rates and heat flow rates in the simulator. The flow field at the outlet of the server was measured by the stereo PIV method. The heat flow rate was determined, based on measuring the temperature field at the inlet and outlet of the simulator and known mass flow rate.

  17. Quenching-rate dependence of the magnetic and mechanical properties of nanocrystalline Fe{sub 73.5}Cu{sub 1}Nb{sub 3}Si{sub 13.5}B{sub 9} ribbons obtained by Joule heating</