WorldWideScience

Sample records for ambient temperature synthesis

  1. Synthesis of ammonia directly from air and water at ambient temperature and pressure.

    Science.gov (United States)

    Lan, Rong; Irvine, John T S; Tao, Shanwen

    2013-01-01

    The N≡N bond (225 kcal mol⁻¹) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N₂ separation and H₂ production stages. A maximum ammonia production rate of 1.14 × 10⁻⁵ mol m⁻² s⁻¹ has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

  2. Synthesis of indium nanoparticles at ambient temperature; simultaneous phase transfer and ripening

    Science.gov (United States)

    Aghazadeh Meshgi, Mohammad; Kriechbaum, Manfred; Biswas, Subhajit; Holmes, Justin D.; Marschner, Christoph

    2016-12-01

    The synthesis of size-monodispersed indium nanoparticles via an innovative simultaneous phase transfer and ripening method is reported. The formation of nanoparticles occurs in a one-step process instead of well-known two-step phase transfer approaches. The synthesis involves the reduction of InCl3 with LiBH4 at ambient temperature and although the reduction occurs at room temperature, fine indium nanoparticles, with a mean diameter of 6.4 ± 0.4 nm, were obtained directly in non-polar n-dodecane. The direct synthesis of indium nanoparticles in n-dodecane facilitates their fast formation and enhances their size-monodispersity. In addition, the nanoparticles were highly stable for more than 2 months. The nanoparticles were characterised by dynamic light scattering (DLS), small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared (FT-IR) spectroscopy to determine their morphology, structure and phase purity.

  3. Thiamine hydrochloride: An efficient catalyst for one-pot synthesis of quinoxaline derivatives at ambient temperature

    Indian Academy of Sciences (India)

    Omprakash B Pawar; Fulchand R Chavan; Venkat S Suryawanshi; Vishnu S Shinde; Narayan D Shinde

    2013-01-01

    Quinoxaline derivatives have been synthesized in high to excellent yields in the presence of thiamine hydrochloride (VB1) as an inexpensive, non-toxic and metal ion free catalyst at ambient temperature.

  4. Efficient and high yield one-pot synthesis of cyclometalated platinum(II) β-diketonates at ambient temperature.

    Science.gov (United States)

    Hudson, Zachary M; Blight, Barry A; Wang, Suning

    2012-04-06

    Cyclometalated Pt(II) β-diketonates are widely used as efficient luminescent materials but are typically prepared at high temperatures in low yields using excess reagents. A one-pot synthesis of these complexes is described employing stoichiometric reagents and short reaction times at ambient temperature, giving yields of up to 94%. The method is applicable to a broad range of substrates including N^C, P^C, and C^C chelate Pt(II) complexes and different β-diketonate ligands.

  5. Ambient temperature recorder

    Science.gov (United States)

    Russell, Larry D.

    1991-01-01

    A temperature data recorder, designated the Ambient Temperature Recorder (ATR-4), was developed at NASA Ames Research Center to meet particular requirements for space life sciences experiments. The small, self-contained, four-channel, battery-powered device records 32 kilobytes of temperature data over a range of -40 to +60 C at four sampling intervals ranging from 1.875 to 15 minutes. Data is stored in its internal electronic memory for later readout by a personal computer.

  6. Biogenic Synthesis of Fluorescent Carbon Dots at Ambient Temperature Using Azadirachta indica (Neem) gum.

    Science.gov (United States)

    Phadke, Chinmay; Mewada, Ashmi; Dharmatti, Roopa; Thakur, Mukeshchand; Pandey, Sunil; Sharon, Madhuri

    2015-07-01

    Synthesis of fluorescent Carbon Dots (CDs) from various carbonaceous materials apparently has acquired lots of interest amongst researchers as the corollary of the properties of CDs; which are subsequently getting unveiled. In this study we report the use of Azadirachta indica (Neem) Gum as a novel natural pre-cursor for synthesis of CDs at room temperature. Water soluble CDs of around 5-8 nm were obtained after treatment of the gum with ethanol and NaOH. These CDs exhibited green fluorescence in UV-light (λ = 365 nm). These CDs were found to be stable, having many bio-linkers attached on their surface, making it suitable for drug attachment and hence can serve as potential candidates for applications like drug delivery vehicles as well as for biosensors.

  7. Rod-Shaped Magnetite Nano/Microparticles Synthesis at Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Balaprasad Ankamwar

    2013-01-01

    Full Text Available Here, we reported room temperature synthesis of Fe3O4 rod-shaped nano/microparticles by chemical reduction method from FeCl3 precursor and NaBH4 as the reducing agent in the presence of the pyrrole as a capping agent. The magnetic Fe3O4 particles were characterized by several methods, such as SEM, XRD, FTIR, and TGA. The average aspect ratio of Fe3O4 rod-shaped particles was ~2.8. These particles were redispersed in deionised water to form a colloidal solution and showed magnetic properties. This economical synthesis route is scalable, and Fe3O4 particles can be exploited for various applications such as MRI contrast enhancement, biodiseperations, Ni-Fe batteries, and as a catalyst.

  8. Large scale synthesis and formation mechanism of silver nanoparticles in solid-state reactions at ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Aiqin, E-mail: zhangaiqin@zzuli.edu.cn [State Laboratory of Surface and Interface Science and Technology, Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Tian, Yakun; Xiao, Yuanhua; Sun, Yuan [State Laboratory of Surface and Interface Science and Technology, Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); Li, Feng [State Laboratory of Surface and Interface Science and Technology, Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, Zhengzhou 450002 (China); American Advanced Nanotechnology, Houston, TX 77459 (United States)

    2015-07-15

    Highlights: • AgNPs were prepared by solid state reaction at ambient temperature. • Only silver nitrate and ascorbic acid were needed in this reaction. • The size of the AgNPs can be tuned conveniently. • Formation mechanism of the AgNPs was investigated. - Abstract: A one-step strategy for preparing Ag nanoparticles (AgNPs) on large scale is demonstrated successfully, based on solid-state reactions at ambient temperature. The environmentally friendly synthesis can be achieved by simply grinding AgNO{sub 3} and ascorbic acid (AA) for about 30 min without adding any solvent and organic protectors. The size of AgNPs can be readily controlled by adjusting the reaction parameters such as AgNO{sub 3}/AA molar ratio and reaction time. The nanostructures of AgNPs and their formation mechanism have been also investigated with XRD, FTIR, FESEM, HRTEM and HPLC–MS. It was found that AA can reduce Ag{sup +} into Ag{sup 0} to form AgNPs directly in accompanying with its first oxidation into 2,3-diketogulonic acid (2,3-DKG) and then a series of fragmentary species of 2,3-DKG.

  9. Ambient temperature signalling in plants.

    Science.gov (United States)

    Wigge, Philip A

    2013-10-01

    Plants are exposed to daily and seasonal fluctuations in temperature. Within the 'ambient' temperature range (about 12-27°C for Arabidopsis) temperature differences have large effects on plant growth and development, disease resistance pathways and the circadian clock without activating temperature stress pathways. It is this developmental sensing and response to non-stressful temperatures that will be covered in this review. Recent advances have revealed key players in mediating temperature signals. The bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) has been shown to be a hub for multiple responses to warmer temperature in Arabidopsis, including flowering and hypocotyl elongation. Changes in chromatin state are involved in transmitting temperature signals to the transcriptome. Determining the precise mechanisms of temperature perception represents an exciting goal for the field.

  10. The relationship between body and ambient temperature and corneal temperature

    DEFF Research Database (Denmark)

    Kessel, Line; Johnson, Leif; Arvidsson, Henrik Sven

    2010-01-01

    Exposure to elevated ambient temperatures has been mentioned as a risk factor for common eye diseases, primarily presbyopia and cataract. The aim of the present study was to examine the relationship among ambient, cornea, and body core temperature.......Exposure to elevated ambient temperatures has been mentioned as a risk factor for common eye diseases, primarily presbyopia and cataract. The aim of the present study was to examine the relationship among ambient, cornea, and body core temperature....

  11. Electronic Ambient-Temperature Recorder

    Science.gov (United States)

    Russell, Larry; Barrows, William

    1995-01-01

    Electronic temperature-recording unit stores data in internal memory for later readout. Records temperatures from minus 40 degrees to plus 60 degrees C at intervals ranging from 1.875 to 15 minutes. With all four data channels operating at 1.875-minute intervals, recorder stores at least 10 days' data. For only one channel at 15-minute intervals, capacity extends to up to 342 days' data. Developed for recording temperatures of instruments and life-science experiments on satellites, space shuttle, and high-altitude aircraft. Adaptable to such terrestrial uses as recording temperatures of perishable goods during transportation and of other systems or processes over long times. Can be placed directly in environment to monitor.

  12. Application of nano SnO2 as a green and recyclable catalyst for the synthesis of 2-aryl or alkylbenzoxazole derivatives under ambient temperature

    Indian Academy of Sciences (India)

    Seyed Mohammad Vahdat; Shima Ghafouri Raz; Saeed Baghery

    2014-05-01

    Application of nano SnO2 as an efficient and benign catalyst has been explored for the synthesis of 2-aryl or alkylbenzoxazole derivatives via condensation reaction of aldehyde with 2-aminophenol. The reactions proceed under heterogeneous and mild conditions in ethanol at room temperature to provide 2-aryl or alkylbenzoxazoles in high yields.

  13. Water Loss Under Hot Ambient Temperatures

    Directory of Open Access Journals (Sweden)

    S. K. Basu

    1978-07-01

    Full Text Available Male 4 rates were ambient temperature (40 degree,42 degree, and 44 degree calcius for different durations of time upto a maximum of 3 hours. It was observed that there was a rapid loss in body weight accompanied by considerable increase in body temperature of the animals during the first hour of exposure. Thereafter the rate of body weight loss and increase in body temperature were slow till the end of observation period. Intolerance to heat appears to be more correlated with critical body temperature rather than the extent of dehydration.

  14. An Efficient, Simple and Green Zn(Phen2Cl2 Complex Catalyzed Synthesis of 4-H-Benzo[b]pyrans in Water at Ambient Temperature

    Directory of Open Access Journals (Sweden)

    E. Mosaddegh

    2011-01-01

    Full Text Available An efficient method for the synthesis of 4-H-benzo[b]pyrans has been developed by the use of Zn(Phen2Cl2(2 mol% as an ecofriendly catalyst. The mixture of an appropriate aldehyde, malononitrile and dimedone in the presence of the Zn(Phen2Cl2 as an inorganic catalyst in water at room temperature resulted excellent yields of the corresponding products in 5 min. Very short experimental time of the reaction, excellent yields, use of water as a green solvent, simple work-up and uses no extra catalyst and purification are the advantages of this method.

  15. Water Power Calculator Temperature and Analog Input/Output Module Ambient Temperature Testing

    Energy Technology Data Exchange (ETDEWEB)

    Mark D. McKay

    2011-02-01

    Water Power Calculator Temperature and Analog input/output Module Ambient Temperature Testing A series of three ambient temperature tests were conducted for the Water Power Calculator development using the INL Calibration Laboratory’s Tenney Environmental Chamber. The ambient temperature test results demonstrate that the Moore Industries Temperature Input Modules, Analog Input Module and Analog Output Module, ambient temperature response meet or exceed the manufactures specifications

  16. Ambient Pressure Synthesis of Nanostructured Tungsten Oxide Crystalline Films

    Directory of Open Access Journals (Sweden)

    H. X. Zhang

    2008-01-01

    Full Text Available We report the results of the ambient pressure synthesis of tungsten oxide nanowires and nanoparticles on AlN substrates using the hot filament CVD techniques. The morphologic surface, crystallographic structures, chemical compositions, and bond structures of the obtained samples have been investigated using scanning electron microscopy (SEM, X-ray diffraction (XRD, energy dispersive X-ray spectroscopy (EDX, and Raman scattering, respectively. Different morphologies were observed for different substrate temperatures, but otherwise identical growth conditions. The experimental measurements reveal the evolutions of the crystalline states and bond structures following the substrate temperatures. Besides, different substrate materials also affected the tungsten oxide nanostructures. Bundles of wire-type tungsten oxide nanowires with a length of up to 5 mm were obtained on Al2O3 substrate. Furthermore, the sensitive properties of the super long nanowires to the gas and different temperature were investigated. The dependence of the sensitivity of tungsten oxide nanowires to the methane as a function of the time was obtained. The sensitive properties of the tungsten oxide nanowires have almost linear relationship with the temperature.

  17. Hydrogen Storage at Ambient Temperature by the Spillover Mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Yang , Ralph T.

    2011-02-04

    superactivated carbons (by following detailed doping and activation conditions given in our publications, e.g., Ref. 12), the storage capacities are increased two-fold (doubled) while slightly more than doubled by Ru doping. The bridging technique remains highly empirical and sample-to-sample consistency is difficult to achieve; however, significant enhancements by spillover can be achieved if the synthesis and pretreatment are done properly. Pitfalls in sample syntheses for both metal doped and bridged sorbents are pointed out in the report; deviations from the synthesis and pretreatment conditions will lead to diminished or no spillover effects. Due to the high bulk densities of zeolites, metal doped zeolites are shown to be most promising for achieving high volumetric storage capacities by spillover. Kinetics of both spillover and reverse spillover (i.e., desorption) at ambient temperature are also studied. This report summarizes the progress made in the project.

  18. Effect of ambient temperature on female endurance performance.

    Science.gov (United States)

    Renberg, Julie; Sandsund, Mariann; Wiggen, Øystein Nordrum; Reinertsen, Randi Eidsmo

    2014-10-01

    Ambient temperature can affect physical performance, and an ambient temperature range of -4 °C to 11 °C is optimal for endurance performance in male athletes. The few similar studies of female athletes appear to have found differences in response to cold between the genders. This study investigated whether ambient temperature affects female endurance performance. Nine athletes performed six tests while running on a treadmill in a climatic chamber at different ambient temperatures: 20, 10, 1, -4, -9 and -14 °C and a wind speed of 5 m s(-1). The exercise protocol consisted of a 10-min warm-up, followed by four 5-min intervals at increasing intensities at 76%, 81%, 85%, and 89% of maximal oxygen consumption. This was followed by an incremental test to exhaustion. Although peak heart rate, body mass loss, and blood lactate concentration after the incremental test to exhaustion increased as the ambient temperature rose, no changes in time to exhaustion, running economy, running speed at lactate threshold or maximal oxygen consumption were found between the different ambient temperature conditions. Endurance performance during one hour of incremental exercise was not affected by ambient temperature in female endurance athletes.

  19. Entrainment of circadian rhythm by ambient temperature cycles in mice.

    Science.gov (United States)

    Refinetti, Roberto

    2010-08-01

    Much is known about how environmental light-dark cycles synchronize circadian rhythms in animals. The ability of environmental cycles of ambient temperature to synchronize circadian rhythms has also been investigated extensively but mostly in ectotherms. In the present study, the synchronization of the circadian rhythm of running-wheel activity by environmental cycles of ambient temperature was studied in laboratory mice. Although all mice were successfully entrained by a light-dark cycle, only 60% to 80% of the mice were entrained by temperature cycles (24-32 degrees C or 24-12 degrees C), and attainment of stable entrainment seemed to take longer under temperature cycles than under a light-dark cycle. This suggests that ambient temperature cycles are weaker zeitgebers than light-dark cycles, which is consistent with the results of the few previous studies using mammalian species. Whereas 80% of the mice were entrained by 24-h temperature cycles, only 60% were entrained by 23-h cycles, and none was entrained by 25-h cycles. The results did not clarify whether entrainment by temperature cycles is caused directly by temperature or indirectly through a temperature effect on locomotor activity, but it is clear that the rhythm of running-wheel activity in mice can be entrained by ambient temperature cycles in the nonnoxious range.

  20. Low ambient temperature and neuroendocrine response to hypoglycemia in men.

    Science.gov (United States)

    Jezová, D; Juránková, E; Kvetnanský, R; Kaciuba-Uscilko, H; Nazar, K; Vigas, M

    1995-12-01

    Nutritional factors, such as an excess or a deficiency of glucose, play an important role in neuroendocrine regulations. Hormonal and metabolic responses to hypoglycemia were examined in healthy non-obese volunteers under conditions of low ambient temperature. Hypoglycemia was induced by intravenous injection of insulin in two randomized trials performed at room temperature and at 4 degrees C. At room temperature, the typical neuroendocrine response to hypoglycemia was established. The increases of ACTH, beta-endorphin, growth hormone and cortisol in response to insulin hypoglycemia failed to be modified by low ambient temperature. Acute cold exposure significantly reduced epinephrine and totally inhibited prolactin response to insulin-induced hypoglycemia. In spite of significant changes in epinephrine response to hypoglycemia at low ambient temperature, no striking differences in plasma glucose levels compared to those measured at room temperature were observed. However, under conditions of low temperature the reestablishment of normoglycemia was delayed. No changes in free fatty acids were found under our experimental conditions. The presented data show that low ambient temperature exerts selective effects on some neuroendocrine and metabolic parameters.

  1. Ambient temperature perception in papaya for papaya ringspot virus interaction.

    Science.gov (United States)

    Mangrauthia, Satendra K; Singh Shakya, Viplendra P; Jain, R K; Praveen, Shelly

    2009-06-01

    Temperature dramatically affects the host-virus interaction. Outbreaks of viral diseases are frequently associated with the ambient temperature required for host development. Using papaya as a host and Papaya ringspot virus (PRSV) as a pathogen, we studied the effect of temperature on the intensity of disease symptoms and virus accumulation. The phenotypic expression of symptoms and viral accumulation were found to be maximum at ambient temperature (26-31 degrees C) of papaya cultivation. However, there was a drastic difference, 10 degrees C above and below the ambient temperature. The underlying mechanism of these well-known observations are not yet understood completely; however, these observations might help find answers in RNA silencing mechanism of plants. Since viral-derived silencing suppressor proteins play a significant role in RNA silencing mechanism, here we show that PRSV-derived Helper component proteinase (HC-Pro) protein has an affinity for small RNAs in a temperature-dependent manner. This suggested the probable role of HC-Pro in the temperature-regulated host-virus relationship.

  2. Effect of Gas Turbine Exhaust Temperature, Stack Temperature and Ambient Temperature on Overall Efficiency of Combine Cycle Power Plant

    OpenAIRE

    Khan, M N; K.P.Tyagi

    2010-01-01

    The gas turbine exhaust temperature, stack temperature and ambient temperature play a very important role during the predication of the performance of combine cycle power plant. This paper covers parametric analysis of effects of gas turbine exhaust temperature, stack temperature and ambient temperature on the overall efficiency of combine cycle power plant keeping the gas turbine efficiency as well as steam turbine efficiency constant. The results shows that out of three variables i.e. turbi...

  3. Water mediated eco-friendly green protocol for one-pot synthesis of -aminophosphonates at ambient conditions

    Indian Academy of Sciences (India)

    Santhosh Reddy Mandha; Manjula Alla; Vittal Rao Bommena

    2014-05-01

    Increasing environmental awareness and economic concerns have led to the consideration of highly efficient one-pot, three-component, green approaches for important organic synthons. We describe here a simple, elegant and high yielding protocol for the synthesis of -aminophosphonates in totally solvent-free, catalyst-free conditions by reacting aldehydes, amines and trimethyl phosphite at ambient temperature.

  4. Ambient air temperature effects on the temperature of sewage sludge composting process

    Institute of Scientific and Technical Information of China (English)

    HUANG Qi-fei; CHEN Tong-bin; GAO Ding; HUANG Ze-chun

    2005-01-01

    Using data obtained with a full-scale sewage sludge composting facility, this paper studied the effects of ambient air temperature on the composting temperature with varying volume ratios of sewage sludge and recycled compost to bulking agent. Two volume ratios were examined experimentally, 1: 0: 1 and 3: 1: 2. The results show that composting temperature was influenced by ambient air temperature and the influence was more significant when composting was in the temperature rising process: composting temperature changed 2.4-6.5℃ when ambient air temperature changed 13℃. On the other hand, the influence was not significant when composting was in the high-temperature and/or temperature falling process: composting temperature changed 0.75-1.3℃ when ambient air temperature changed 8-15 ℃. Hysteresis effect was observed in composting temperature's responses to ambient air temperature. When the ventilation capability of pile was excellent(at a volume ratio of 1:0:1), the hysteresis time was short and ranging 1.1-1.2 h. On the contrary, when the proportion of added bulking agent was low, therefore less porosity in the substrate(at a volume ratio of 3:1:2), the hysteresis time was long and ranging 1.9-3.1 h.

  5. Apparatus for storage of compressed gas at ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lowther, F.E.

    1986-10-28

    This patent describes an engine system including a combustion engine and an oxidizer subsystem for high density gaseous oxidizer. The oxidizer subsystem comprises: a storage vessel; adsorbent material in the storage vessel capable of adsorbing relatively large volumes of the gaseous oxidizer at ambient temperature and of preventing the instantaneous release thereof in the event of a rupture of the vessel, the storage vessel being operatively connected for delivery of oxidizer to the engine for combination with fuel therein to power the engine.

  6. [Research on Raman spectra of isooctane at ambient temperature and ambient pressure to 1. 2 GPa].

    Science.gov (United States)

    Zhang, Fei-fei; Zheng, Hai-fei

    2012-03-01

    The experimental study of the Raman spectral character for liquid isooctane (2,2,4-trimethylpentane, ATM) was con ducted by moissanite anvil cell at the pressure of 0-1.2 GPa and the ambient temperature. The results show that the Raman peaks of the C-H stretching vibration shift to higher frenquencies with increasing pressures. The relations between the system pressure and peaks positions is given as following: v2 873 = 0.002 8P+2 873.3; v2 905 = 0.004 8P+2 905.4; v2 935 = 0.002 7P+ 2 935.0; v2 960 = 0.012P+2 960.9. The Raman spectra of isooctane abruptly changed at the pressure about 1.0 GPa and the liquid-solid phase transition was observed by microscope. With the freezing pressure at ambient temperature and the melting temperature available at 1 atm, the authors got the liquid-solid phase diagram of isooctane. According to Clapeyron equation, the authors obtained the differences of volume and entropy for the liquid-solid phase transition of isooctane: deltaV(m) = 4.46 x 10(-6) m3 x mol-1 and deltaS = -30.32 J x K(-1) x mol(-1).

  7. Numerical Analysis of Exergy for Air-Conditioning Influenced by Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Jing-Nang Lee

    2014-07-01

    Full Text Available The article presents numerical analysis of exergy for air-conditioning influenced by ambient temperature. The model of numerical simulation uses an integrated air conditioning system exposed in varied ambient temperature to observe change of the four main devices, the compressor, the condenser, the capillary, and the evaporator in correspondence to ambient temperature. The analysis devices of the four devices’s exergy influenced by the varied ambient temperature and found that the capillary has unusual increasing exergy loss vs. increasing ambient temperature in comparison to the other devices. The result shows that reducing exergy loss of the capillary influenced by the ambient temperature is the key for improving working efficiency of an air-conditioning system when influence of the ambient temperature is considered. The higher ambient temperature causes the larger pressure drop of capillary and more exergy loss.

  8. Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B.; Salmeron, Miquel

    2009-02-27

    We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.

  9. 14 CFR 25.1527 - Ambient air temperature and operating altitude.

    Science.gov (United States)

    2010-01-01

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

  10. Solution based synthesis of simple fcc Si nano-crystals under ambient conditions.

    Science.gov (United States)

    Balcı, Mustafa H; Sæterli, Ragnhild; Maria, Jerome; Lindgren, Mikael; Holmestad, Randi; Grande, Tor; Einarsrud, Mari-Ann

    2013-02-28

    We demonstrate for the first time that simple face-centered cubic (fcc) silicon nano-crystals can be produced by a solution based bottom-up synthesis route under ambient conditions. Simple fcc Si nano-crystals (2-7 nm) were prepared at room temperature by using sodium cyclopentadienide as a reducing agent for silicon tetrachloride. Photoluminescence emission at 550 nm was observed for the fcc silicon nano-crystals upon excitation at 340 nm, indicating that fcc Si nano-crystals were exhibiting direct bandgap like semiconductor properties with very fast radiative recombination rates. The new synthesis route makes possible the production and study of simple fcc polymorphs of Si nano-crystals with an easy alteration of surface termination groups.

  11. Ambient temperature influences the neural benefits of exercise.

    Science.gov (United States)

    Maynard, Mark E; Chung, Chasity; Comer, Ashley; Nelson, Katharine; Tran, Jamie; Werries, Nadja; Barton, Emily A; Spinetta, Michael; Leasure, J Leigh

    2016-02-15

    Many of the neural benefits of exercise require weeks to manifest. It would be useful to accelerate onset of exercise-driven plastic changes, such as increased hippocampal neurogenesis. Exercise represents a significant challenge to the brain because it produces heat, but brain temperature does not rise during exercise in the cold. This study tested the hypothesis that exercise in cold ambient temperature would stimulate hippocampal neurogenesis more than exercise in room or hot conditions. Adult female rats had exercise access 2h per day for 5 days at either room (20 °C), cold (4.5 °C) or hot (37.5 °C) temperature. To label dividing hippocampal precursor cells, animals received daily injections of BrdU. Brains were immunohistochemically processed for dividing cells (Ki67+), surviving cells (BrdU+) and new neurons (doublecortin, DCX) in the hippocampal dentate gyrus. Animals exercising at room temperature ran significantly farther than animals exercising in cold or hot conditions (room 1490 ± 400 m; cold 440 ± 102 m; hot 291 ± 56 m). We therefore analyzed the number of Ki67+, BrdU+ and DCX+ cells normalized for shortest distance run. Contrary to our hypothesis, exercise in either cold or hot conditions generated significantly more Ki67+, BrdU+ and DCX+ cells compared to exercise at room temperature. Thus, a limited amount of running in either cold or hot ambient conditions generates more new cells than a much greater distance run at room temperature. Taken together, our results suggest a simple means by which to augment exercise effects, yet minimize exercise time.

  12. Effect of ambient temperature and relative humidity on interfacial temperature during early stages of drop evaporation.

    Science.gov (United States)

    Fukatani, Yuki; Orejon, Daniel; Kita, Yutaku; Takata, Yasuyuki; Kim, Jungho; Sefiane, Khellil

    2016-04-01

    Understanding drop evaporation mechanisms is important for many industrial, biological, and other applications. Drops of organic solvents undergoing evaporation have been found to display distinct thermal patterns, which in turn depend on the physical properties of the liquid, the substrate, and ambient conditions. These patterns have been reported previously to be bulk patterns from the solid-liquid to the liquid-gas drop interface. In the present work the effect of ambient temperature and humidity during the first stage of evaporation, i.e., pinned contact line, is studied paying special attention to the thermal information retrieved at the liquid-gas interface through IR thermography. This is coupled with drop profile monitoring to experimentally investigate the effect of ambient temperature and relative humidity on the drop interfacial thermal patterns and the evaporation rate. Results indicate that self-generated thermal patterns are enhanced by an increase in ambient temperature and/or a decrease in humidity. The more active thermal patterns observed at high ambient temperatures are explained in light of a greater temperature difference generated between the apex and the edge of the drop due to greater evaporative cooling. On the other hand, the presence of water humidity in the atmosphere is found to decrease the temperature difference along the drop interface due to the heat of adsorption, absorption and/or that of condensation of water onto the ethanol drops. The control, i.e., enhancement or suppression, of these thermal patterns at the drop interface by means of ambient temperature and relative humidity is quantified and reported.

  13. Ammonia synthesis at low temperatures

    DEFF Research Database (Denmark)

    Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

    2000-01-01

    Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...... have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics....

  14. Ambient temperature-independent dual-band mid-infrared radiation thermometry.

    Science.gov (United States)

    Lü, You; He, Xin; Wei, Zhong-Hui; Sun, Zhi-Yuan; Chang, Song-Tao

    2016-03-20

    For temperature measurements of targets at low temperatures, dual-band radiation thermometry using mid-infrared detectors has been investigated extensively. However, the accuracy is greatly affected by the reflected ambient radiation and stray radiation, which depend on the ambient temperature. To ensure measurement accuracy, an improved dual-band measurement model is established by considering the reflected ambient radiation and the stray radiation. The effect of ambient temperature fluctuation on temperature measurement is then further analyzed in detail. Experimental results of measuring a gray-body confirm that the proposed method yields high accuracy at varying ambient temperatures. This method provides a practical approach to remove the effect of ambient temperature fluctuations on temperature measurements.

  15. Habitat type and ambient temperature contribute to bill morphology.

    Science.gov (United States)

    Luther, David; Greenberg, Russell

    2014-03-01

    Avian bills are iconic structures for the study of ecology and evolution, with hypotheses about the morphological structure of bills dating back to Darwin. Several ecological and physiological hypotheses have been developed to explain the evolution of the morphology of bill shape. Here, we test some of these hypotheses such as the role of habitat, ambient temperature, body size, intraspecific competition, and ecological release on the evolution of bill morphology. Bill morphology and tarsus length were measured from museum specimens of yellow warblers, and grouped by habitat type, sex, and subspecies. We calculated the mean maximum daily temperature for the month of July, the hottest month for breeding specimens at each collecting location. Analysis of covariance models predicted total bill surface area as a function of sex, habitat type, body size, and temperature, and model selection techniques were used to select the best model. Habitat, mangrove forests compared with inland habitats, and climate had the largest effects on bill size. Coastal wetland habitats and island populations of yellow warblers had similar bill morphology, both of which are larger than mainland inland populations. Temperate but not tropical subspecies exhibited sexual dimorphism in bill morphology. Overall, this study provides evidence that multiple environmental factors, such as temperature and habitat, contribute to the evolution of bill morphology.

  16. Ambient temperature affects the temperature threshold for TRPM8 activation through interaction of phosphatidylinositol 4,5-bisphosphate.

    Science.gov (United States)

    Fujita, Fumitaka; Uchida, Kunitoshi; Takaishi, Masayuki; Sokabe, Takaaki; Tominaga, Makoto

    2013-04-03

    Cold sensation is an important and fundamental sense for animals and it is known to be affected by ambient temperature. Transient Receptor Potential Melastatin 8 (TRPM8), a nonselective cation channel expressed in a subset of peripheral afferent fibers, acts as a cold sensor, having an activation threshold of ∼28°C. Although the cold temperature threshold of TRPM8 is affected by menthol or pH, ambient temperature has not been reported to affect it. Because the cold temperature threshold was thought to be unchanged by alterations in ambient temperature, the relativity of temperature sensing in different ambient temperatures could not be understood at the level of molecular function of thermosensitive TRP channels. Here, we show that ambient temperature changed the temperature threshold for activation of human and rat TRPM8 in a heterologous expression system and cold responses in mouse DRG neurons. Moreover, reducing the level of cellular phosphatidylinositol 4,5-bisphosphate (PIP2) attenuated changes in the cold temperature threshold after alterations in ambient temperature. A single amino acid mutation at position 1008 in the C terminus of TRPM8 (arginine to glutamine) also attenuated changes in the cold temperature threshold induced by ambient temperature. These findings suggest that ambient temperature does affect the temperature threshold for TRPM8 activation through interaction of PIP2.

  17. Thermoelectric Energy Harvesting from Transient Ambient Temperature Gradients

    Science.gov (United States)

    Moser, André; Erd, Metin; Kostic, Milos; Cobry, Keith; Kroener, Michael; Woias, Peter

    2012-06-01

    We examine a thermoelectric harvester that converts electrical energy from the naturally occurring temperature difference between ambient air and large thermal storage capacitors such as building walls or the soil. For maximum power output, the harvester design is implemented in two steps: source matching of the thermal and electrical interfaces to the energy source (system level) followed by load matching of the generator to these interfaces (subsystem level). Therefore, we measure thermal source properties such as the temperature difference, the air velocity, and the cutoff frequency in two application scenarios (road tunnel and office building). We extend a stationary model of the harvester into the time domain to account for transient behavior of the source. Based on the model and the source measurements, we perform the source and load matching. The resulting harvester consists of a pin fin heat sink with a thermal resistance of 6.2 K/W and a cutoff frequency 2.5 times greater than that of the source, a thermoelectric generator, and a DC/DC step-up converter starting at a total temperature difference of only Δ T = 1.2 K. In a final road tunnel field test, this optimized harvester converts 70 mJ of electrical energy per day without any direct solar irradiation. The energy provided by the harvester enables 415 data transmissions from a wireless sensor node per day.

  18. Optimized Synthesis of Carbon Aerogels via Ambient Pressure Drying Process as Electrode for Supercapacitors

    Institute of Scientific and Technical Information of China (English)

    YUAN Lei; CHANG Lijuan; FU Zhibing; YANG Xi; JIAO Xingli; TANG Yongjian; LIU Xichuan; WANG Chaoyang

    2015-01-01

    Carbon aerogels were synthesized via ambient pressure drying process using resorcinol-formaldehyde as precursor and P123 to strengthen their skeletons. CO2 activation technology was implemented to improve surface areas and adjust pore size distribution. The synthesis process was optimized, and the morphology, structure, adsorption properties and electrochemical behavior of different samples were characterized. The CO2-activated samples achieved a high specific capacitance of 129.2 F/g in 6 M KOH electrolytes at the current density of 1 mA/cm2 within the voltage range of 0-0.8 V. The optimized activation temperature and duration were determined to be 950℃and 4 h, respectively.

  19. Thermoelectric energy harvesting from small ambient temperature transients

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Andre

    2012-07-01

    Wireless sensor networks (WSNs) represent a key technology, used, for instance, in structural health monitoring, building automation systems, or traffic surveillance. Supplying power to a network of spatially distributed sensor nodes, especially at remote locations, is a large challenge: power grids are reliable but costly to install, whereas batteries provide a high flexibility in the installation but have a limited lifetime. This dilemma can be overcome by micro energy harvesting which offers both: reliability and flexibility. Micro energy harvesters are able to convert low grade ambient energy into useful electrical energy and thus provide power for wireless sensor networks or other electronic devices - in-situ, off-grid, and with an almost unlimited lifetime. Thermal energy is an omnipresent source of ambient energy: The day-night-cycle of the sun causes a temperature variation in the ambient air as well as arbitrary solids (soil, building walls, etc.). Unlike the air, solids have a large thermal inertia which dampens the temperature variation. This physical process leads to a temperature difference {Delta}T = T{sub air} - T{sub solid} between air and solid that can be converted directly into electrical energy by a thermoelectric generator (TEG). Thermal and electrical interfaces are necessary to connect the TEG to the thermal energy source (T{sub air}, T{sub solid}) and the electrical load (WSN). Reliable operation of the WSN may only be ensured if the harvester provides sufficient electrical energy, i.e. operates at its maximum power point. The goal of this thesis is to study, design, and test thermoelectric harvesters generating electrical energy from small ambient temperature transients in order to self-sufficiently power a WSN. Current research into thermoelectric energy harvesting, especially analytical modeling and application in the field are treated insufficiently. Therefore, a time-dependent analytical model of the harvester's output power is set

  20. Revealing the association between cerebrovascular accidents and ambient temperature: a meta-analysis

    Science.gov (United States)

    Zorrilla-Vaca, Andrés; Healy, Ryan Jacob; Silva-Medina, Melissa M.

    2016-10-01

    The association between cerebrovascular accidents (CVA) and weather has been described across several studies showing multiple conflicting results. In this paper, we aim to conduct a meta-analysis to further clarify this association, as well as to find the potential sources of heterogeneity. PubMed, EMBASE, and Google Scholar were searched from inception through 2015, for articles analyzing the correlation between the incidence of CVA and temperature. A pooled effect size (ES) was estimated using random effects model and expressed as absolute values. Subgroup analyses by type of CVA were also performed. Heterogeneity and influence of covariates—including geographic latitude of the study site, male percentage, average temperature, and time interval—were assessed by meta-regression analysis. Twenty-six articles underwent full data extraction and scoring. A total of 19,736 subjects with CVA from 12 different countries were included and grouped as ischemic strokes (IS; n = 14,199), intracerebral hemorrhages (ICH; n = 3798), and subarachnoid hemorrhages (SAH; n = 1739). Lower ambient temperature was significantly associated with increase in incidence of overall CVA when using unadjusted (pooled ES = 0.23, P < 0.001) and adjusted data (pooled ES = 0.03, P = 0.003). Subgroup analyses showed that lower temperature has higher impact on the incidence of ICH (pooled ES = 0.34, P < 0.001), than that of IS (pooled ES = 0.22, P < 0.001) and SAH (pooled ES = 0.11, P = 0.012). In meta-regression analysis, the geographic latitude of the study site was the most influencing factor on this association (Z-score = 8.68). Synthesis of the existing data provides evidence supporting that a lower ambient temperature increases the incidence of CVA. Further population-based studies conducted at negative latitudes are needed to clarify the influence of this factor.

  1. A Novel RAFT Polymerization under UV Radiation at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Nianfa Yang; Lican Lu; Yuanli Cai

    2005-01-01

    @@ 1Introduction Reversible Addition Fragmentation chain Transfer (RAFT) polymerization has become a highly versatile technique for the controlled/"living" radical polymerization of a wide range of monomers under various conditions[1,2]. The RAFT polymerization was carried out using a dithiocarboxylate or trithiocarbonate as a Chain Transfer Agent (CTA), which mediates the growing chain radicals via an equilibrium[1,2]. From both academic and industrial standpoints, it is clearly desirable to develop a RAFT process under mild conditions. Rizzardo, et al [3] and McCormick's group[4] have respectively reported RAFT polymerization using conventional radical initiators at ambient temperature by adjusting the structure of CTA. The RAFT Polymerization initiated by γ-radiation has also reported recently[5]. Quinn, et al [6] have reported the RAFT polymerization under UV radiation using CTA as the source of primary radicals at 42 ℃, which was well controlled at low conversions (below 20% ) but less controlled at higher conversions (over 20% ) due to the photolysis of CTA residues under UV radiation.

  2. ambiental

    Directory of Open Access Journals (Sweden)

    Roque Leal Salcedo

    2008-01-01

    Full Text Available El derecho internacional ambiental es un conocimiento de carácter transversal, que entre otras consideraciones refleja las preocupaciones de la sociedad por la implementación de un modelo de desarrollo sustentable para el respeto a las reglas del medio natural que garantizan la integridad y renovación de los sistemas naturales. El presente artículo enfoca esta visión a través del análisis de material documental revisado, entre ellos tratados internacionales que permiten distinguir el desarrollo del derecho internacional ambiental y el papel de Organización de las Naciones Unidas (ONU, en el propósito común del derecho individual y colectivo de disfrutar de una vida, un ambiente seguro, sano y ecológicamente equilibrado. En función a estas disertaciones las consideraciones finales exponen parte de la visión que ha estructurado la ONU y que representan un aporte considerable en el fomento de la conciencia mundial sobre la necesidad de establecer vínculos entre las naciones para el continuo desarrollo de esta rama del derecho.

  3. Simple Fabrication of Mesoporous Silica with Remarkable High Temperature Stability at Neutral pH and Ambient Conditions from TEOS

    Science.gov (United States)

    Hess, David; Vippagunta, Radha; Watkins, James

    2007-03-01

    Traditional silica synthesis processes can yield well ordered materials, but the synthesis conditions also lead to incomplete condensation of the silica network, which results in significant structural contraction upon calcination and limited thermal, hydrothermal and mechanical stability. Here we report the synthesis that, surprisingly, yields nearly complete condensation of the silica network (virtually all Q4 linkages) using cysteamine as the catalyst and polyoxyethylene surfactants as the structure directing agents in buffered solution at neutral pH and ambient temperature. Recently, small molecule bifunctional amines, including cysteamine, were evaluated by Morse and co-workers and found to produce silica from TEOS(JACS 2005, 127, 35). Our work combines the cysteamine catalyst system with structure-directing block copolymer surfactants at neutral pH and ambient temperature to produce mesoporous silica. The addition of tetraethyl orthosilicate (TEOS) to a solution of containing cysteamine, citrate buffer (pH 7.2) and 5wt Brij amphiphilic block copolymer (polyethylene oxide-polyethylene) yields mesoporous silica. The resulting mesoporous silica powder was analyzed using XRD, TGA, FTIR, TEM, and NMR. The materials were found to exhibit stability under extreme temperature calcinations (up to 800 C) in the presence of water. SAXS shows that 1.0 shrinkage upon calcination up to 800C. 29Si NMR analysis indicates a fully condensed silica network, Q4 linkages, in accordance with this observation.

  4. The dependence of surface temperature on IGBTs load and ambient temperature

    Science.gov (United States)

    Alexander, Čaja; Marek, Patsch

    2015-05-01

    Currently, older power electronics and electrotechnics are improvement and at the same time developing new and more efficient devices. These devices produce in their activities a significant part of the heat which, if not effectively drained, causing damage to these elements. In this case, it is important to develop new and more efficient cooling system. The most widespread of modern methods of cooling is the cooling by heat pipe. This contribution is aimed at cooling the insulated-gate bipolar transistor (IGBT) elements by loop heat pipe (LHP). IGBTs are very prone to damage due to high temperatures, and therefore is the important that the surface temperature was below 100°C. It was therefore created a model that examined what impact of surface temperature on the IGBT element and heat removal at different load and constant ambient temperature.

  5. The dependence of surface temperature on IGBTs load and ambient temperature

    Directory of Open Access Journals (Sweden)

    Alexander Čaja

    2015-01-01

    Full Text Available Currently, older power electronics and electrotechnics are improvement and at the same time developing new and more efficient devices. These devices produce in their activities a significant part of the heat which, if not effectively drained, causing damage to these elements. In this case, it is important to develop new and more efficient cooling system. The most widespread of modern methods of cooling is the cooling by heat pipe. This contribution is aimed at cooling the insulated-gate bipolar transistor (IGBT elements by loop heat pipe (LHP. IGBTs are very prone to damage due to high temperatures, and therefore is the important that the surface temperature was below 100°C. It was therefore created a model that examined what impact of surface temperature on the IGBT element and heat removal at different load and constant ambient temperature.

  6. A method to measure internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures

    Science.gov (United States)

    Tian, Qijie; Chang, Songtao; Li, Zhou; He, Fengyun; Qiao, Yanfeng

    2017-03-01

    The suppression level of internal stray radiation is a key criterion for infrared imaging systems, especially for high-precision cryogenic infrared imaging systems. To achieve accurate measurement for internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures, a measurement method, which is based on radiometric calibration, is presented in this paper. First of all, the calibration formula is deduced considering the integration time, and the effect of ambient temperature on internal stray radiation is further analyzed in detail. Then, an approach is proposed to measure the internal stray radiation of cryogenic infrared imaging systems under various ambient temperatures. By calibrating the system under two ambient temperatures, the quantitative relation between the internal stray radiation and the ambient temperature can be acquired, and then the internal stray radiation of the cryogenic infrared imaging system under various ambient temperatures can be calculated. Finally, several experiments are performed in a chamber with controllable inside temperatures to evaluate the effectiveness of the proposed method. Experimental results indicate that the proposed method can be used to measure internal stray radiation with high accuracy at various ambient temperatures and integration times. The proposed method has some advantages, such as simple implementation and the capability of high-precision measurement. The measurement results can be used to guide the stray radiation suppression and to test whether the internal stray radiation suppression performance meets the requirement or not.

  7. Low temperature synthesis of porous silicate ceramics

    OpenAIRE

    Méndez Enríquez Y.; Vlasova M.; Leon I.; Kakazey M.G.; Dominguez-Patiño M.; Isaeva L.; Tomila T.

    2007-01-01

    Impregnation of a polyurethane sponge with kaolin, feldspar, silica, fusible glass slurry followed by temperature treatment in air in the temperature range 800-1000 0 C leads to the formation of aluminosilicate ceramics with a set pore size. The low-temperature synthesis of porous ceramics is based on the stage-by-stage formation of low-temperature eutectics and thermodestruction of polyurethane sponge.

  8. Low temperature synthesis of porous silicate ceramics

    Directory of Open Access Journals (Sweden)

    Méndez Enríquez Y.

    2007-01-01

    Full Text Available Impregnation of a polyurethane sponge with kaolin, feldspar, silica, fusible glass slurry followed by temperature treatment in air in the temperature range 800-1000 0 C leads to the formation of aluminosilicate ceramics with a set pore size. The low-temperature synthesis of porous ceramics is based on the stage-by-stage formation of low-temperature eutectics and thermodestruction of polyurethane sponge.

  9. Influence of the ambient air temperature on the electrical contact reliability of electromagnetic relay

    Institute of Scientific and Technical Information of China (English)

    YAO Fang; ZHENG Jian-rong; HUANG Zhang-wu

    2007-01-01

    The dynamic contact resistances of HH52P electromagnetic relays are measured under different ambient air temperature. Their diagnostic parameters are extracted and determined. It is found that the ambient air temperature obviously influences some parameters. In order to research its influence on the electrical contact reliability of electromagnetic relay, the statistic analysis is applied to study the static contact resistance, the max of the dynamic contact resistance and the bounce time. It is found that the ambient air temperature regularly influences the three parameters. Thoroughly, the phenomenon is studied and analyzed in the point of material science so as to probe into the essential matter of it.

  10. Ambient Temperature Based Thermal Aware Energy Efficient ROM Design on FPGA

    DEFF Research Database (Denmark)

    Saini, Rishita; Bansal, Neha; Bansal, Meenakshi

    2015-01-01

    Thermal aware design is currently gaining importance in VLSI research domain. In this work, we are going to design thermal aware energy efficient ROM on Virtex-5 FPGA. Ambient Temperature, airflow, and heat sink profile play a significant role in thermal aware hardware design life cycle. Ambient...

  11. Formic Acid Dehydrogenation on Au-Based Catalysts at Near-Ambient Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ojeda, Manuel; Iglesia, Enrique

    2008-11-24

    Formic acid (HCOOH) is a convenient hydrogen carrier in fuel cells designed for portable use. Recent studies have shown that HCOOH decomposition is catalyzed with Ru-based complexes in the aqueous phase at near-ambient temperatures. HCOOH decomposition reactions are used frequently to probe the effects of alloying and cluster size and of geometric and electronic factors in catalysis. These studies have concluded that Pt is the most active metal for HCOOH decomposition, at least as large crystallites and extended surfaces. The identity and oxidation state of surface metal atoms influence the relative rates of dehydrogenation (HCOOH {yields} H{sub 2} + CO{sub 2}) and dehydration (HCOOH {yields} H{sub 2}O + CO) routes, a selectivity requirement for the synthesis of CO-free H{sub 2} streams for low-temperature fuel cells. Group Ib and Group VIII noble metals catalyze dehydrogenation selectively, while base metals and metal oxides catalyze both routes, either directly or indirectly via subsequent water-gas shift (WGS) reactions.

  12. Influence of ambient temperature and diurnal temperature range on incidence of cardiac arrhythmias

    Science.gov (United States)

    Kim, Jayeun; Kim, Ho

    2016-08-01

    We investigated the association between ambient temperature and diurnal temperature range (DTR) and the exacerbation of arrhythmia symptoms, using data from 31,629 arrhythmia-related emergency department (ED) visits in Seoul, Korea. Linear regression analyses with allowances for over-dispersion were applied to temperature variables and ED visits, adjusted for various environmental factors. The effects were expressed as percentage changes in the risk of arrhythmia-related ED visits up to 5 days later, with 95 % confidence intervals (CI), per 1 °C increase in DTR and 1 °C decrease in mean temperature. The overall risk of ED visits increased by 1.06 % (95 % CI 0.39 %, 1.73 %) for temperature and by 1.84 % (0.34, 3.37 %) for DTR. A season-specific effect was detected for temperature during both fall (1.18 % [0.01, 2.37 %]) and winter (0.87 % [0.07, 1.67 %]), and for DTR during spring (3.76 % [0.34, 7.29 %]). Females were more vulnerable, with 1.57 % [0.56, 2.59 %] and 3.84 % [1.53, 6.20 %] for the changes in temperature and DTR, respectively. An age-specific effect was detected for DTR, with 3.13 % [0.95, 5.36 %] for age ≥ 65 years, while a greater increased risk with temperature decrease was observed among those aged arrhythmias depended more on the change in DTR (4.72 % [0.37, 9.26 %]). These findings provide evidence that low-temperature and elevated DTR influence the occurrence of arrhythmia exacerbations or symptoms, suggesting a possible strategy for reducing risk by encouraging vulnerable populations to minimize exposure.

  13. Significance and influence of the ambient temperature as a rate factor of steel reinforcement corrosion

    Indian Academy of Sciences (India)

    V Živica

    2002-10-01

    The rate of corrosion of reinforcement being an electrochemical process, undoubtedly is dependent even on the level of the ambient temperature. Therefore, the ambient temperature seems to be an important factor of the corrosion rate and the durability of the reinforced concrete structures in aggressive environment. The present data on the influence and significance of the ambient temperature in the process of corrosion of reinforcement of the reinforced structures are surprisingly limited and poor. It seems that it is supposed to be a simple increase of corrosion rate when the ambient temperature is increased. The lack of information was a motivation for the present study. It was aimed at the experimental research of the influence of the increase of the ambient temperature on the rate of chloride induced corrosion of steel reinforcement. The results obtained show that the influence of the studied factor is more complex showing an acceleration effect till a temperature of 40°C diversified by the inhibition effects with further increase of the ambient temperature.

  14. Influence of the Ambient Temperature, to the Hydrogen Fuel Cell Functioning

    Directory of Open Access Journals (Sweden)

    POPOVICI Ovidiu

    2012-10-01

    Full Text Available The reversible fuel cell can be used to produce hydrogen. The hydrogen is further the chemical energy source to produce electrical energy using the fuel cell. The ambient temperature will influence theparameters of the hydrogen fuel cell.

  15. Effects of the ambient temperature on the airflow across a Caucasian nasal cavity.

    Science.gov (United States)

    Burgos, M A; Sanmiguel-Rojas, E; Martín-Alcántara, A; Hidalgo-Martínez, M

    2014-03-01

    We analyse the effects of the air ambient temperature on the airflow across a Caucasian nasal cavity under different ambient temperatures using CFD simulations. A three-dimensional nasal model was constructed from high-resolution computed tomography images for a nasal cavity from a Caucasian male adult. An exhaustive parametric study was performed to analyse the laminar-compressible flow driven by two different pressure drops between the nostrils and the nasopharynx, which induced calm breathing flow rates ࣈ 5.7 L/min and ࣈ 11.3 L/min. The inlet air temperature covered the range - 10(o) C ⩽ To ⩽50(o) C. We observed that, keeping constant the wall temperature of the nasal cavity at 37(o) C, the ambient temperature affects mainly the airflow velocity into the valve region. Surprisingly, we found an excellent linear relationship between the ambient temperature and the air average temperature reached at different cross sections, independently of the pressure drop applied. Finally, we have also observed that the spatial evolution of the mean temperature data along the nasal cavity can be collapsed for all ambient temperatures analysed with the introduction of suitable dimensionless variables, and this evolution can be modelled with the help of hyperbolic functions, which are based on the heat exchanger theory.

  16. Study of the Recombination of H2 and O2 at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The hydrophobic catalysts was developed at Chalk River Nuclear Laboratories and was used in the recombiner operated at ambient conditions. The advantage of operating a recombiner at ambient temperature were recognized by several researchers. It is clear that significant savings can be realized if the recombiner is operated at ambient temperature without the need for costly heaters and coolers. And the process is safer and more uncomplicated than conventional processes.The experimental conditions as followings: carrier gas is Ar; concentration of H2 is 1%;

  17. Impact of ambient temperature on spring-based relative gravimeter measurements

    Science.gov (United States)

    Fores, B.; Champollion, C.; Moigne, N. Le; Chery, J.

    2016-10-01

    In this paper, we investigate the impact of ambient temperature changes on the gravity reading of spring-based relative gravimeters. Controlled heating experiments using two Scintrex CG5 gravimeters allowed us to determine a linear correlation (R 2> 0.9) between ambient temperature and gravity variations. The relation is stable and constant for the two CG5 we used: -5 nm/s2/° C. A linear relation is also seen between gravity and residual sensor temperature variations (R 2> 0.75), but contrary to ambient temperature, this relation is neither constant over time nor similar between the two instruments. The linear correction of ambient temperature on the controlled heating time series reduced the standard deviation at least by a factor of 2, to less than 10 nm/s2 . The laboratory results allowed for reprocessing the data gathered on a field survey that originally aimed to characterize local hydrological heterogeneities on a karstic area. The correction of two years of monthly CG5 measurements from ambient temperature variations halved the standard deviation (from 62 to 32 nm/s2 ) and led us to a better hydrological interpretation. Although the origin of this effect is uncertain, we suggest that an imperfect control of the sensor temperature may be involved, as well as a change of the properties of an electronic component.

  18. Comparability of tympanic and oral mercury thermometers at high ambient temperatures

    Directory of Open Access Journals (Sweden)

    Chue Amy L

    2012-07-01

    Full Text Available Abstract Background Body temperature can be measured in seconds with tympanic thermometers as opposed to minutes with mercury ones. The aim of this study was to compare tympanic and oral mercury thermometer measurements under high ambient field temperatures. Results Tympanic temperature (measured thrice by 3 operators was compared to oral temperature measured once with a mercury-in-glass thermometer in 201 patients (aged ≥5 years, on the Thai-Myanmar border. Ambient temperature was measured with an electronic thermo-hygrometer. Participants had a mean [min-max] age of 27 [5–60] years and 42% (84 were febrile by oral thermometer. The mean difference in the mercury and tympanic temperature measurement for all observers/devices was 0.09 (95%CI 0.07-0.12°C and intra-class correlation for repeat tympanic measurements was high (≥0.97 for each observer. Deviations in tympanic temperatures were not related to ambient temperature. Conclusion Clinically significant differences were not observed between oral and tympanic temperature measurements at high ambient temperatures in a rural tropical setting.

  19. Effects of ambient oxygen concentration on soot temperature and concentration for biodiesel and diesel spray combustion

    KAUST Repository

    Zhang, Ji

    2015-06-01

    Ambient oxygen concentration, a key variable directly related to exhaust gas recirculation (EGR) levels in diesel engines, plays a significant role in particulate matter (PM) and nitrogen oxides (NOx) emissions. The utilization of biodiesel in diesel engines has been investigated over the last decades for its renewable characteristics and lower emissions compared to diesel. In an earlier work, we demonstrated that the soot temperature and concentration of biodiesel were lower than diesel under regular diesel engine conditions without EGR. Soot concentration was quantified by a parameter called KL factor. As a continuous effort, this paper presents an experimental investigation of the ambient oxygen concentration on soot temperature and KL factor during biodiesel and diesel spray combustion. The experiment was implemented in a constant volume chamber system, where the ambient oxygen concentration varied from 21 to 10% and the ambient temperature was kept to 1,000 K. A high speed two-color pyrometry technique was used to measure transient soot temperature and the KL factor of the spray flame. The soot temperature of biodiesel is found to be lower than that of diesel under the same conditions, which follows the same trend from our previous results found when the ambient temperature changes to 21% oxygen conditions. A reduction in ambient oxygen concentration generally reduces the soot temperature for both fuels. However, this is a complicated effect on soot processes as the change of oxygen concentration greatly affects the balance between soot formation and oxidation. The KL factor is observed to be the highest at 12% O2 for diesel and 18% O2 for biodiesel, respectively. On the other hand, the 10% O2 condition shows the lowest KL factor for both fuels. These results can provide quantitative experimental evidences to optimize the ambient oxygen concentration for diesel engines using different fuels for better emissions characteristics. © 2014 American Society of

  20. Type 2 diabetes, but not obesity, prevalence is positively associated with ambient temperature.

    Science.gov (United States)

    Speakman, John R; Heidari-Bakavoli, Sahar

    2016-08-01

    Cold exposure stimulates energy expenditure and glucose disposal. If these factors play a significant role in whole body energy balance, and glucose homeostasis, it is predicted that both obesity and type 2 diabetes prevalence would be lower where it is colder. Previous studies have noted connections between ambient temperature and obesity, but the direction of the effect is confused. No previous studies have explored the link of type 2 diabetes to ambient temperature. We used county level data for obesity and diabetes prevalence across the mainland USA and matched this to county level ambient temperature data. Average ambient temperature explained 5.7% of the spatial variation in obesity and 29.6% of the spatial variation in type 2 diabetes prevalence. Correcting the type 2 diabetes data for the effect of obesity reduced the explained variation to 26.8%. Even when correcting for obesity, poverty and race, ambient temperature explained 12.4% of the variation in the prevalence of type 2 diabetes, and this significant effect remained when latitude was entered into the model as a predictor. When obesity prevalence was corrected for poverty and race the significant effect of temperature disappeared. Enhancing energy expenditure by cold exposure will likely not impact obesity significantly, but may be useful to combat type 2 diabetes.

  1. The effect of ambient temperature on gross-efficiency in cycling

    NARCIS (Netherlands)

    Hettinga, F.J.; Koning, J.J. de; Vrijer, A. de; Wüst, R.C.I.; Daanen, H.A.M.; Foster, C.

    2007-01-01

    Time-trial performance deteriorates in the heat. This might potentially be the result of a temperature-induced decrease in gross-efficiency (GE). The effect of high ambient temperature on GE during cycling will be studied, with the intent of determining if a heat-induced change in GE could account f

  2. Experimental and casework validation of ambient temperature corrections in forensic entomology.

    Science.gov (United States)

    Johnson, Aidan P; Wallman, James F; Archer, Melanie S

    2012-01-01

    This paper expands on Archer (J Forensic Sci 49, 2004, 553), examining additional factors affecting ambient temperature correction of weather station data in forensic entomology. Sixteen hypothetical body discovery sites (BDSs) in Victoria and New South Wales (Australia), both in autumn and in summer, were compared to test whether the accuracy of correlation was affected by (i) length of correlation period; (ii) distance between BDS and weather station; and (iii) periodicity of ambient temperature measurements. The accuracy of correlations in data sets from real Victorian and NSW forensic entomology cases was also examined. Correlations increased weather data accuracy in all experiments, but significant differences in accuracy were found only between periodicity treatments. We found that a >5°C difference between average values of body in situ and correlation period weather station data was predictive of correlations that decreased the accuracy of ambient temperatures estimated using correlation. Practitioners should inspect their weather data sets for such differences.

  3. Coesite Formation at Ambient Pressure and Low Temperatures

    Directory of Open Access Journals (Sweden)

    J. R. Martínez

    2008-01-01

    Full Text Available Partial crystallization of silica xerogel in the form of coesite has been obtained at low-pressure conditions and temperatures of ∼565∘C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel samples were prepared by the sol-gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of annealing temperature. It was found that partial crystallization of the glass matrix in the form of coestite was obtained at lower pressure than those specified by the phase diagram. Chlorophyll aggregates were added to the starting solutions which, upon thermal treatments, form small colloidal particles in the glass matrix. The presence of coesite is corroborated by the Rietveld refinement method.

  4. Creep testing of nodular iron at ambient and elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Martinsson, Aasa; Andersson-Oestling, Henrik C.M.; Seitisleam, Facredin; Wu, Rui; Sandstroem, Rolf (Swerea KIMAB AB, Stockholm (Sweden))

    2010-12-15

    The creep strain at room temperature, 100 and 125 deg C has been investigated for the ferritic nodular cast iron insert intended for use as the load-bearing part of canisters for long term disposal of spent nuclear fuel. The microstructure consisted of ferrite, graphite nodules of different sizes, compacted graphite and pearlite. Creep tests have been performed for up to 41,000 h. The specimens were cut out from material taken from two genuine inserts, I30 and I55. After creep testing, the specimens from the 100 deg C tests were hardness tested and a metallographic examination was performed. Creep strains at all temperatures appear to be logarithmic, and accumulation of creep strain diminishes with time. The time dependence of the creep strain is consistent to the W-model for primary creep. During the loading plastic strains up to 1% appeared. The maximum recorded creep strain after the loading phase was 0.025%. This makes the creep strains technically insignificant. Acoustic emission recordings during the loading of the room temperature tests showed no sounds or other evidence of microcracking during the loading phase. There is no evidence that the hardness or the graphite microstructure changed during the creep tests

  5. Splicing-related genes are alternatively spliced upon changes in ambient temperatures in plants

    Science.gov (United States)

    Bucher, Johan; Lammers, Michiel; Busscher-Lange, Jacqueline; Bonnema, Guusje; Rodenburg, Nicole; Proveniers, Marcel C. G.; Angenent, Gerco C.

    2017-01-01

    Plants adjust their development and architecture to small variations in ambient temperature. In a time in which temperatures are rising world-wide, the mechanism by which plants are able to sense temperature fluctuations and adapt to it, is becoming of special interest. By performing RNA-sequencing on two Arabidopsis accession and one Brassica species exposed to temperature alterations, we showed that alternative splicing is an important mechanism in ambient temperature sensing and adaptation. We found that amongst the differentially alternatively spliced genes, splicing related genes are enriched, suggesting that the splicing machinery itself is targeted for alternative splicing when temperature changes. Moreover, we showed that many different components of the splicing machinery are targeted for ambient temperature regulated alternative splicing. Mutant analysis of a splicing related gene that was differentially spliced in two of the genotypes showed an altered flowering time response to different temperatures. We propose a two-step mechanism where temperature directly influences alternative splicing of the splicing machinery genes, followed by a second step where the altered splicing machinery affects splicing of downstream genes involved in the adaptation to altered temperatures. PMID:28257507

  6. Effect of Ambient Temperature on Performance of Grid-Connected Inverter Installed in Thailand

    Directory of Open Access Journals (Sweden)

    Kamonpan Chumpolrat

    2014-01-01

    Full Text Available The effects of temperature on performance of a grid-connected inverter, and also on a photovoltaic (PV system installed in Thailand have been investigated. It was found that the maximum efficiency of the inverter showed 2.5% drop when ambient temperature was above 37°C. The inverter performed efficiently in November and December, the months of high irradiance, and monthly average ambient temperature of lower than 35°C, allowing relatively high system performance ratio in this period. Our results show that high temperature provides negative impacts not only on the PV modules, but also on the performance of the inverter. Thus, the effect of temperature on the inverter efficiency should be taken into account when predicting energy yield or analyzing losses of the PV systems—especially in high temperature regions.

  7. Influence of Ambient Temperature on Nanosecond and Picosecond Laser-Induced Bulk Damage of Fused Silica

    Directory of Open Access Journals (Sweden)

    L. Yang

    2014-01-01

    Full Text Available The nanosecond (ns and picosecond (ps pulsed laser-induced damage behaviors of fused silica under cryogenic and room temperature have been investigated. The laser-induced damage threshold (LIDT and damage probability are used to understand the damage behavior at different ambient temperatures. The results show that the LIDTs for both ns and ps slightly increased at cryogenic temperature compared to that at room temperature. Meanwhile, the damage probability has an inverse trend; that is, the damage probability at low temperature is smaller than that at room temperature. A theoretical model based on heated crystal lattice is well consistent with the experimental results.

  8. Impact of Seasonal Variant Temperatures and Laboratory Room Ambient Temperature on Mortality of Rats with Ischemic Brain Injury

    Science.gov (United States)

    Gopalakrishanan, Sivakumar; Babu, Mg. Ramesh; Thangarajan, Rajesh; Punja, Dhiren; Jaganath, Vidyadhara Devarunda; Kanth, Akriti B.; Rao, Mohandas

    2016-01-01

    Introduction A popular rat model for hypoperfusion ischemic brain injury is bilateral common carotid artery occlusion (BCCAO). BCCAO surgery when performed in varying geographical locations and during different seasons of the year is reported to have variable mortality rates. Studies have also documented the diminishing influence of Ketamine-Xylazine (KT-XY) on thermoregulatory functions in rodents. Aim To explore the impact of seasonal variant temperatures and laboratory room ambient temperatures on mortality of rats following BCCAO surgery. Materials and Methods The study has two parts: 1 The first part is an analysis of a three year retrospective data to explore the association between the geographical season (hot summer and cold winter) induced laboratory room ambient temperature variations and the mortality rate in KT-XY anaesthetized BCCAO rats. 2. The second part investigated the effect of conditioned laboratory room ambient temperature (CAT) (23-250C) in KT-XY anaesthetized BCCAO group of rats. Rats were divided into 4 groups(n =8/group) as-Normal control, BCCAO and Sham BCCAO where they were all exposed to unconditioned ambient temperature (UCAT) during their surgery and postoperative care. And finally fourth group rats exposed to CAT during the BCCAO surgery and postoperative care. Results Pearson’s chi-square test indicates a significantly high association (p<0.006) between post-BCCAO mortality and hot season of the year. CAT during the hot season reduced the mortality rate (24% less) in post- BCCAO rats compared to the rats of UCAT. Conclusion Despite seasonal variations in temperature, conditioning the laboratory room ambient temperatures to 23–250C, induces hypothermia in KT-XY anaesthetized ischemic brain injured rodents and improves their survival rate. PMID:27190796

  9. Quantum Coherent Dynamics at Ambient Temperature in Photosynthetic Molecules

    CERN Document Server

    Walters, Zachary B

    2011-01-01

    Photosynthetic antenna complexes are responsible for absorbing energy from sunlight and transmitting it to remote locations where it can be stored. Recent experiments have found that this process involves long-lived quantum coherence between pigment molecules, called chromophores, which make up these complexes. Expected to decay within 100 fs at room temperature, these coherences were instead found to persist for picosecond time scales, despite having no apparent isolation from the thermal environment of the cell. This paper derives a quantum master equation which describes the coherent evolution of a system in strong contact with a thermal environment. Conditions necessary for long coherence lifetimes are identified, and the role of coherence in efficient energy transport is illuminated. Static spectra and exciton transfer rates for the PE545 complex of the cryptophyte algae CS24 are calculated and shown to have good agreement with experiment.

  10. Dependence of electric strength on the ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Čaja, Alexander, E-mail: alexander.caja@fstroj.uniza.sk, E-mail: patrik.nemec@fstroj.uniza.sk, E-mail: milan.malcho@fstroj.uniza.sk; Nemec, Patrik, E-mail: alexander.caja@fstroj.uniza.sk, E-mail: patrik.nemec@fstroj.uniza.sk, E-mail: milan.malcho@fstroj.uniza.sk; Malcho, Milan, E-mail: alexander.caja@fstroj.uniza.sk, E-mail: patrik.nemec@fstroj.uniza.sk, E-mail: milan.malcho@fstroj.uniza.sk [University of Žilina, Faculty of Mechanical Engineering, Department of Power Engeneering, Univerzitná 1, 010 26 Žilina (Slovakia)

    2014-08-06

    At present, the volume concentration of electronic components in their miniaturization to different types of microchips and increasing their performance raises the problem of cooling such elements due to the increasing density of heat flow of heat loss. Compliance with safe operating temperature of active semiconductor element is very closely related to the reliability and durability not only components, but also the entire device. Often it is also necessary to electrically isolate the unit from the side of the cooler air. Cooling demand by natural convection is typical for applications with high operating reliability. To the reliability of the system for removing heat loss increased, it is necessary to minimize need to use the mechanically or electrically powered elements, such as circulation pumps or fans. Experience to date with applications of heat pipe in specific systems appears to be the most appropriate method of cooling.

  11. Single-step ambient-air synthesis of graphene from renewable precursors as electrochemical genosensor

    Science.gov (United States)

    Seo, Dong Han; Pineda, Shafique; Fang, Jinghua; Gozukara, Yesim; Yick, Samuel; Bendavid, Avi; Lam, Simon Kwai Hung; Murdock, Adrian T.; Murphy, Anthony B.; Han, Zhao Jun; Ostrikov, Kostya (Ken)

    2017-01-01

    Thermal chemical vapour deposition techniques for graphene fabrication, while promising, are thus far limited by resource-consuming and energy-intensive principles. In particular, purified gases and extensive vacuum processing are necessary for creating a highly controlled environment, isolated from ambient air, to enable the growth of graphene films. Here we exploit the ambient-air environment to enable the growth of graphene films, without the need for compressed gases. A renewable natural precursor, soybean oil, is transformed into continuous graphene films, composed of single-to-few layers, in a single step. The enabling parameters for controlled synthesis and tailored properties of the graphene film are discussed, and a mechanism for the ambient-air growth is proposed. Furthermore, the functionality of the graphene is demonstrated through direct utilization as an electrode to realize an effective electrochemical genosensor. Our method is applicable to other types of renewable precursors and may open a new avenue for low-cost synthesis of graphene films.

  12. Single-step ambient-air synthesis of graphene from renewable precursors as electrochemical genosensor

    Science.gov (United States)

    Seo, Dong Han; Pineda, Shafique; Fang, Jinghua; Gozukara, Yesim; Yick, Samuel; Bendavid, Avi; Lam, Simon Kwai Hung; Murdock, Adrian T.; Murphy, Anthony B.; Han, Zhao Jun; Ostrikov, Kostya (Ken)

    2017-01-01

    Thermal chemical vapour deposition techniques for graphene fabrication, while promising, are thus far limited by resource-consuming and energy-intensive principles. In particular, purified gases and extensive vacuum processing are necessary for creating a highly controlled environment, isolated from ambient air, to enable the growth of graphene films. Here we exploit the ambient-air environment to enable the growth of graphene films, without the need for compressed gases. A renewable natural precursor, soybean oil, is transformed into continuous graphene films, composed of single-to-few layers, in a single step. The enabling parameters for controlled synthesis and tailored properties of the graphene film are discussed, and a mechanism for the ambient-air growth is proposed. Furthermore, the functionality of the graphene is demonstrated through direct utilization as an electrode to realize an effective electrochemical genosensor. Our method is applicable to other types of renewable precursors and may open a new avenue for low-cost synthesis of graphene films. PMID:28134336

  13. Influence of the ambient temperature during heat pipe manufacturing on its function and heat transport ability

    Directory of Open Access Journals (Sweden)

    Čaja A.

    2014-03-01

    Full Text Available Heat pipe is heat transfer device working at a minimum temperature difference of evaporator and condenser. Operating temperature of the heat pipe determine by properties of the working substance and pressure achieved during production. The contribution is focused on the determining the effect of the initial surrounding temperature where the heat pipe is manufactured and on the obtaining performance characteristics produced heat pipes in dependence of manufacturing temperature. Generally hold, that the boiling point of the working liquid decrease with decreasing ambient pressure. Based on this can be suppose that producing of lower ambient temperature during heat pipe manufacturing, will create the lower pressure, the boiling point of the working fluid will lower too and the heat pipe should be better performance characteristics.

  14. Ambient temperature cured TiB2 cathode coating for aluminum electrolysis

    Institute of Scientific and Technical Information of China (English)

    赖延清; 李庆余; 杨建红; 李劼

    2003-01-01

    The concept of ambient temperature curable TiB2 cathode coating was put forward, and the ambient temperature curable TiB2 cathode coating was prepared successfully. Differing from the previous TiB2 cathode coating solidified approximately at 200 ℃,the ambient temperature curable TiB2 cathode coating can be solidified at room temperature, so the heating equipment is not necessary, which simplifies the preparation process and facilitates the industrial application of TiB2 cathode coating. Many kinds of resin and curing agent were investigated. On the above-mentioned basis, the ambient temperature curable TiB2 cathode coating was prepared with furan resin 5 500 mixed with complex resins B as carbon binder and DXG1 as curing agent in 24 h. The results show that the properties of prepared coating are excellent, the electrical resistivity is 29.8 μΩ*m, the compressive strength is 33.6 MPa, which are all better than the relevant properties of partially graphitized cathode carbon block for aluminum electrolysis prescribed by the GB 8744-88. SEM morphologies show that the section morphology of the TiB2 coating is unaltered during the electrolysis test, the TiB2 coating can be used in aluminum electrolysis industry to save energy and prolong the life of aluminum electrolysis cell.

  15. Effect of ambient temperature and light intensity on physiological reactions of heavy broiler chickens.

    Science.gov (United States)

    Olanrewaju, H A; Purswell, J L; Collier, S D; Branton, S L

    2010-12-01

    The effects of ambient temperature, light intensity, and their interaction on blood acid-base balance, metabolites, and electrolytes in broiler chickens under environmentally controlled conditions were examined in 2 trials. The experiment consisted of a factorial arrangement of treatments in a randomized complete block design. The 9 treatments consisted of 3 levels of temperatures (low = 15.6°C; moderate = 21.1°C; high = 26.7°C) from 21 to 56 d of age and 3 levels of light intensities (0.5, 3.0, 20 lx) from 8 to 56 d of age at 50% RH. A total of 540 Ross 708 chicks were randomly distributed into 9 environmentally controlled chambers (30 male and 30 female chicks/chamber) at 1 d of age. Feed and water were provided ad libitum. Venous blood samples were collected on d 21 (baseline), 28, 42, and 56. High ambient temperature significantly (P ≤ 0.05) reduced BW, partial pressure of CO(2), bicarbonate, hematocrit, hemoglobin, K(+), and Na(+) along with significantly (P ≤ 0.05) elevated pH level, Cl(-), glucose, osmolality, and anion gap concentrations. Partial pressure of O(2) was slightly increased in response to increased ambient temperature. There was no effect of light intensity on most of the blood variables examined. Acid-base regulation during high ambient temperature and light intensity exposure did not deteriorate despite a lower partial pressure of CO(2), which consequently increased blood pH because of a compensatory decrease in HCO(3)(-) concentration. Plasma corticosterone was not affected by temperature, light intensity, or their interaction. These results indicate that continuous exposure of broiler chickens to varying light intensities had a minor effect on physiological blood variables, whereas high ambient temperature markedly affected various blood variables without inducing stress in broilers.

  16. Soot measurements for diesel and biodiesel spray combustion under high temperature highly diluted ambient conditions

    KAUST Repository

    Zhang, Ji

    2014-11-01

    This paper presents the soot temperature and KL factor for biodiesel, namely fatty acid methyl ester (FAME) and diesel fuel combustion in a constant volume chamber using a two-color technique. The KL factor is a parameter for soot concentration, where K is an absorption coefficient and proportional to the number density of soot particles, L is the geometric thickness of the flame along the optical detection axis, and KL factor is proportional to soot volume fraction. The main objective is to explore a combustion regime called high-temperature and highly-diluted combustion (HTHDC) and compare it with the conventional and low-temperature combustion (LTC) modes. The three different combustion regimes are implemented under different ambient temperatures (800 K, 1000 K, and 1400 K) and ambient oxygen concentrations (10%, 15%, and 21%). Results are presented in terms of soot temperature and KL factor images, time-resolved pixel-averaged soot temperature, KL factor, and spatially integrated KL factor over the soot area. The time-averaged results for these three regimes are compared for both diesel and biodiesel fuels. Results show complex combined effects of the ambient temperature and oxygen concentration, and that two-color temperature for the HTHDC mode at the 10% oxygen level can actually be lower than the conventional mode. Increasing ambient oxygen and temperature increases soot temperature. Diesel fuel results in higher soot temperature than biodiesel for all three regimes. Results also show that diesel and biodiesel fuels have very different burning and sooting behavior under the three different combustion regimes. For diesel fuel, the HTHDC regime offers better results in terms of lower soot than the conventional and LTC regimes, and the 10% O2, 1400 K ambient condition shows the lowest soot concentration while maintaining a moderate two-color temperature. For biodiesel, the 15% O2, 800 K ambient condition shows some advantages in terms of reducing soot

  17. Effects of Elevated Ambient Temperature on Reproductive Outcomes and Offspring Growth Depend on Exposure Time

    Directory of Open Access Journals (Sweden)

    Huda Yahia Hamid

    2012-01-01

    Full Text Available Reproductive performance has been shown to be greatly affected by changes in environmental factors, such as temperature. However, it is also crucial to identify the particular stage of pregnancy that is most adversely affected by elevated ambient temperature. The aims of this study were to determine the effect on reproductive outcomes of exposure to elevated ambient temperature during different stages of pregnancy and to determine the effect of prenatal heat stress on offspring growth. Sixty pregnant rats were used in this study. The rats were divided equally into four groups as group 1 (control, group 2 (exposed to elevated temperature following implantation, group 3 (exposed to elevated temperature during pre- and periimplantation, and group 4 (exposed to elevated temperature during pre- and periimplantation and following implantation. Groups 3 and 4 had prolonged gestation periods, reduced litter sizes, and male-biased sex ratios. Moreover, the growth patterns of group 3 and 4 pups were adversely affected by prenatal exposure to elevated temperature. The differences between group 1 and group 3 and between group 1 and group 4 were highly significant. However, no significant differences were observed between groups 1 and 2 in the gestation length, sex ratios, and growth patterns. Thus, it can be concluded that exposure to elevated ambient temperature during pre- and periimplantation has stronger adverse effects on reproductive outcomes and offspring growth than postimplantation exposure.

  18. Evaporative cooling for lactating sows under high ambient temperature

    Directory of Open Access Journals (Sweden)

    Charles Kiefer

    2012-05-01

    Full Text Available Two experiments were conducted to evaluate the evaporative cooling of the air at farrowing on the performance of lactating sows under high environmental temperature conditions in the Central West region of Brazil. One hundred and forty-four lactating sows - 46 of first and second farrowing (experiment I and 98 from the third to eighth farrowing (experiment II - were used. Sows were distributed in experimental design of randomized blocks consisting of two rooms (with air cooling and control, with the sow as the experimental unit. The average duration of lactation was 21 days. Sows were fed ad libitum with the same lactation diet. In experiment I, the air cooling increased the daily feed intake, reduced the total and percent weight loss, increased the weight of the piglets and litters at weaning and improved the daily milk production of sows. However, the air cooling did not affect the weight of the sows or the number of piglets at weaning. In experiment II the air cooling increased the daily feed intake of the sows, reduced the total and percent weight loss, increased the weight and the weight gain of the piglets and litters and improved the daily milk production of the sows. Air cooling enables the increase of the daily feed intake and, therefore, of nutrients by the sows, with consequent reduction of mobilization of body reserves and the increase in the milk production and in the weight of piglets and litters at weaning, regardless the farrowing order of the sow.

  19. SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature

    CERN Document Server

    Rimmer, Robert; Preble, Joseph P; Reece, Charles E

    2005-01-01

    In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maint...

  20. Enhanced neuroendocrine response to insulin tolerance test performed under increased ambient temperature.

    Science.gov (United States)

    Jezová, D; Kvetnanský, R; Nazar, K; Vigas, M

    1998-01-01

    The hypothesis that an increase in ambient temperature modulates neuroendocrine response in clinically used provocative pituitary function tests was verified. Healthy male volunteers were subjected to insulin tolerance tests in two randomized trials. In the first trial hypoglycemia was induced by a bolus injection of insulin (0.1 U per kg of BW, i.v.) at room temperature. In the second trial, the subjects were exposed to increased ambient temperature for 45 min before insulin injection and for 45 min thereafter. The environmental temperature was selected to increase body temperature less than 1C. Under conditions of increased temperature basal hormone levels as measured in antecubital venous blood samples failed to be modified and the hypoglycemia was less severe. Nevertheless, the responses of most (beta-endorphin, ACTH, prolactin, catecholamines), but not all (growth hormone, cortisol), hormones to hypoglycemia were exaggerated. The remarkable increase in ACTH and beta-endorphin release was not accompanied by concomitant increase of plasma cortisol response. The sympathetic-adrenomedullary system was significantly activated, which was manifested particularly by enhanced norepinephrine release. Growth hormone response to hypoglycemia was not modified, while that of prolactin was enhanced. Thus during evaluation of neuroendocrine function under clinical conditions, changes in ambient and body temperature should not be underestimated.

  1. Prediction of vertical distribution and ambient development temperature of Baltic cod, Gadus morhua L., eggs

    DEFF Research Database (Denmark)

    Wieland, Kai; Jarre, Astrid

    1997-01-01

    situation was observed. Mean ambient temperatures, calculated from the predicted vertical distributions of the eggs and used for the computation of egg developmental times, were overestimated by 0.05 degrees C on average. This corresponds to an error in prediction of egg developmental time of less than 1%...

  2. Gold-Catalyzed Aerobic Oxidation of 5-Hydroxymethylfurfural in Water at Ambient Temperature

    DEFF Research Database (Denmark)

    Gorbanev, Yury; Kegnæs, Søren; Woodley, John

    2009-01-01

    The aerobic oxidation of 5-hydroxymethylfurfural, a versatile biomass-derived chemical, is examined in water with a titania-supported gold-nanoparticle catalyst at ambient temperature (30 degrees C). The selectivity of the reaction towords 2,5-furandicarboxylic acid and the intermediate oxidation...

  3. Why cross-national differences in role overload? Don't overlook ambient temperature!

    NARCIS (Netherlands)

    Van de Vliert, E.; Van Yperen, N.W.

    1996-01-01

    The finding that, across nations, power distance (expected and accepted unequal interpersonal influence) Is positively related to role overload (Peterson et al., 1995) might he an artifact of the relation between role overload and ambient temperature or other third factors. We related data on power

  4. Manufacturing Demonstration Facility: Low Temperature Materials Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graham, David E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moon, Ji-Won [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Datskos, Panos G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duty, Chad E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gresback, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ivanov, Ilia N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jacobs, Christopher B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jellison, Gerald Earle [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jang, Gyoung Gug [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Joshi, Pooran C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jung, Hyunsung [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Phelps, Tommy [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-30

    The Manufacturing Demonstration Facility (MDF) low temperature materials synthesis project was established to demonstrate a scalable and sustainable process to produce nanoparticles (NPs) for advanced manufacturing. Previous methods to chemically synthesize NPs typically required expensive, high-purity inorganic chemical reagents, organic solvents and high temperatures. These processes were typically applied at small laboratory scales at yields sufficient for NP characterization, but insufficient to support roll-to-roll processing efforts or device fabrication. The new NanoFermentation processes described here operated at a low temperature (~60 C) in low-cost, aqueous media using bacteria that produce extracellular NPs with controlled size and elemental stoichiometry. Up-scaling activities successfully demonstrated high NP yields and quality in a 900-L pilot-scale reactor, establishing this NanoFermentation process as a competitive biomanufacturing strategy to produce NPs for advanced manufacturing of power electronics, solid-state lighting and sensors.

  5. Water-free Alkaline Polymer-inorganic Acid Complexes with High Conductivity at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    O.V.Chervakov; M.V.Andriianova; V.V.Riabenko; A.V.Markevich; E.M.Shembel; D.Meshri

    2007-01-01

    1 Results Recently increased interest is shown to proton conducting materials based on the alkaline polymer-inorganic acid complexes that is caused by a possibility of their application as the high-temperature electrolyte systems for various electrochemical devices (fuel cells,sensors,lithium power sources etc.).Complexes of inorganic acids with the alkaline polymers (polybenzimidazoles[1],polyvinylpyridines[2]) are characterized by high ionic conductivity at ambient temperatures (up to 10-2 Ω-1·cm-1) a...

  6. The monitoring and fatigue behavior of CFCCs at ambient temperature and 1000{degrees}C

    Energy Technology Data Exchange (ETDEWEB)

    Miriyala, N.; Liaw, P.K.; McHargue, C.J. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

    1997-04-01

    Metallographically polished flexure bars of Nicalon/SiC and Nicalon/alumina composites were subjected to monotonic and cycle-fatigue loadings, with loading either parallel or normal to the fabric plies. The fabric orientation did not significantly affect the mechanical behavior of the Nicalon/SiC composite at ambient temperature. However, the mechanical behavior of the Nicalon/alumina composite was significantly affected by the fabric orientation at ambient temperature in air and at 1000{degrees}C in argon atmosphere. In addition, there was a significant degradation in the fatigue performance of the alumina matrix composite at the elevated temperature, owing to creep in the material and degradation in the fiber strength.

  7. Effect of ambient temperatures on disinfection efficiency of various sludge treatment technologies.

    Science.gov (United States)

    Bauerfeld, Katrin

    2014-01-01

    Sewage sludge produced during municipal wastewater treatment has to be treated efficiently in order to reduce impacts on the environment and on public health. In Germany and many countries, large quantities of sludge are reused in agriculture in order to recycle nutrients and organic material. In order to quantify the effect of different ambient temperatures on conventional and advanced sludge treatment technologies as well as on disinfection efficiency, a comprehensive research study was performed at Braunschweig Institute of Technology. The detailed results show that ambient temperature has a strong effect on biological liquid sludge stabilization and on natural dewatering and drying technologies, although microbiological quality of treated sludge, indicated by Escherichia coli concentration, does not meet the requirements for unrestricted reuse in agriculture. Composting and lime treatment of sludge are most efficient on reducing E. coli, as high temperatures and high pH values arise in the material respectively.

  8. Effects of Imidapril on Venous Blood Gas Values in Broiler Chickens Exposed to Low Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Xueqin HAO; Meng LI; Shouyan ZHANG; Yongshu WANG; Tongwen SUN

    2013-01-01

    [Objective] This study was designed to evaluate the effects of imidapril on blood gas parameters in broiler chickens.[Method] Twenty-four chickens were randomly divided into three groups (n=8),control group,low temperature group and imidapril group.Chickens in low temperature group and imidapril group were exposed to low ambient temperature (12-18 ℃) from age at 14 d to 45 d,whereas the control group was exposed to 24-30 ℃; chickens in imidapril group were gavaged with imidapril (3 mg/kg) once daily for 30 d.At age of 45 d,blood was taken from wing vein and blood gas parameters were evaluated by blood gas analyzer in Luoyang Central Hospital Affiliated to Zhengzhou University.[Result] Imidapril significantly increased hematocrit (HCT) and total hemoglobin content (THBC) and blood Na concentration in broiler chickens exposed to low ambient temperature.No significant differences were observed in pH,Pco2,Po2,K+,Ca2+,HCO3-,HCO3std,Tco2,BE and SO2c.[Conclusion] Imidapril increases hematocrit,total hemoglobin content and blood Na+concentration in chickens exposed to low ambient temperature.

  9. The importance of ambient temperature to growth and the induction of flowering.

    Directory of Open Access Journals (Sweden)

    C. Robertson Mcclung

    2016-08-01

    Full Text Available Plant development is exquisitely sensitive to the environment. Light quantity, quality, and duration (photoperiod have profound effects on vegetative morphology and flowering time. Recent studies have demonstrated that ambient temperature is a similarly potent stimulus influencing morphology and flowering. In Arabidopsis, ambient temperatures that are high, but not so high as to induce a heat stress response, confer morphological changes that resemble the shade avoidance syndrome. Similarly, these high but not stressful temperatures can accelerate flowering under short day conditions as effectively as exposure to long days. Photoperiodic flowering entails a series of external coincidences, in which environmental cycles of light and dark must coincide with an internal cycle in gene expression established by the endogenous circadian clock. It is evident that a similar model of external coincidence applies to the effects of elevated ambient temperature on both vegetative morphology and the vegetative to reproductive transition. Further study is imperative, because global warming is predicted to have major effects on the performance and distribution of wild species and strong adverse effects on crop yields. It is critical to understand temperature perception and response at a mechanistic level and to integrate this knowledge with our understanding of other environmental responses, including biotic and abiotic stresses, in order to improve crop production sufficiently to sustainably feed an expanding world population.

  10. Design of Cold-Formed Steel Screw Connections with Gypsum Sheathing at Ambient and Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2016-09-01

    Full Text Available Load-bearing cold-formed steel (CFS walls sheathed with double layers of gypsum plasterboard on both sides have demonstrated good fire resistance and attracted increasing interest for use in mid-rise CFS structures. As the main connection method, screw connections between CFS and gypsum sheathing play an important role in both the structural design and fire resistance of this wall system. However, studies on the mechanical behavior of screw connections with double-layer gypsum sheathing are still limited. In this study, 200 monotonic tests of screw connections with single- or double-layer gypsum sheathing at both ambient and elevated temperatures were conducted. The failure of screw connections with double-layer gypsum sheathing in shear was different from that of single-layer gypsum sheathing connections at ambient temperature, and it could be described as the breaking of the loaded sheathing edge combined with significant screw tilting and the loaded sheathing edge flexing fracture. However, the screw tilting and flexing fracture of the loaded sheathing edge gradually disappear at elevated temperatures. In addition, the influence of the loaded edge distance, double-layer sheathing and elevated temperatures is discussed in detail with clear conclusions. A unified design formula for the shear strength of screw connections with gypsum sheathing is proposed for ambient and elevated temperatures with adequate accuracy. A simplified load–displacement model with the post-peak branch is developed to evaluate the load–displacement response of screw connections with gypsum sheathing at ambient and elevated temperatures.

  11. Effect of Ambient Temperature on Body Temperature and Rest Metabolic Rate in Apodemus chevrieri During Postnatal Development

    Directory of Open Access Journals (Sweden)

    Zhu Wan-long

    2014-05-01

    Full Text Available In order to investigate the ability of constant temperature and thermoregulation in Apodemus chevrieri, body temperature and rest metabolic rate (RMR were measured during postnatal development (1~42 day when the A. chevrieri exposed different ambient temperature. The result showed that: body temperature and RMR of pups in A. chevrieri increased according to the increase of ambient temperature during 1 day to 7 day, showed character of poikilotherms; body temperature of pups were lower in low temperature(5oC and 10oC, relatively and RMR significant increased when day age is 14 day, it indicated that the pups showed a certain degree of thermoregulation in this phase. Its thermoregulation ability developed quickly during 7 day to 14 day. RMR of pups was extreme significantly higher in low temperature than that in other temperature when day age was 21 day, it showed that the pups had some thermoregulation to low temperature stimulation. The RMR of pups was showed increasing trend in high temperature(35oC when 28 day; when day age was 35 day and 42 day, the thermal neutral zone were 22.5 to 30oC and approaching its adult level. All of these results indicated that pups of A. chevrieri in the different growing period had different thermogenesis and energy allocation to maintain stable to body temperature, thermogenesis was weaker in the early phase of postnatal development, most of energy is used to its growth. After pups were weaned, the ability of constant temperature and thermoregulation developed quickly to adjust variations of environment during postnatal development.

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

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2014-01-01

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

  13. Temperature oscillations near natural nuclear reactor cores and the potential for prebiotic oligomer synthesis.

    Science.gov (United States)

    Adam, Zachary R

    2016-06-01

    Geologic settings capable of driving prebiotic oligomer synthesis reactions remain a relatively unexplored aspect of origins of life research. Natural nuclear reactors are an example of Precambrian energy sources that produced unique temperature fluctuations. Heat transfer models indicate that water-moderated, convectively-cooled natural fission reactors in porous host rocks create temperature oscillations that resemble those employed in polymerase chain reaction (PCR) devices to artificially amplify oligonucleotides. This temperature profile is characterized by short-duration pulses up to 70-100 °C, followed by a sustained period of temperatures in the range of 30-70 °C, and finally a period of relaxation to ambient temperatures until the cycle is restarted by a fresh influx of pore water. For a given reactor configuration, temperature maxima and the time required to relax to ambient temperatures depend most strongly on the aggregate effect of host rock permeability in decreasing the thermal expansion and increasing the viscosity and evaporation temperature of the pore fluids. Once formed, fission-fueled reactors can sustain multi-kilowatt-level power production for 10(5)-10(6) years, ensuring microenvironmental longevity and chemical output. The model outputs indicate that organic synthesis on young planetary bodies with a sizeable reservoir of fissile material can involve more sophisticated energy dissipation pathways than modern terrestrial analog settings alone would suggest.

  14. Temperature oscillations near natural nuclear reactor cores and the potential for prebiotic oligomer synthesis

    Science.gov (United States)

    Adam, Zachary R.

    2016-06-01

    Geologic settings capable of driving prebiotic oligomer synthesis reactions remain a relatively unexplored aspect of origins of life research. Natural nuclear reactors are an example of Precambrian energy sources that produced unique temperature fluctuations. Heat transfer models indicate that water-moderated, convectively-cooled natural fission reactors in porous host rocks create temperature oscillations that resemble those employed in polymerase chain reaction (PCR) devices to artificially amplify oligonucleotides. This temperature profile is characterized by short-duration pulses up to 70-100 °C, followed by a sustained period of temperatures in the range of 30-70 °C, and finally a period of relaxation to ambient temperatures until the cycle is restarted by a fresh influx of pore water. For a given reactor configuration, temperature maxima and the time required to relax to ambient temperatures depend most strongly on the aggregate effect of host rock permeability in decreasing the thermal expansion and increasing the viscosity and evaporation temperature of the pore fluids. Once formed, fission-fueled reactors can sustain multi-kilowatt-level power production for 105-106 years, ensuring microenvironmental longevity and chemical output. The model outputs indicate that organic synthesis on young planetary bodies with a sizeable reservoir of fissile material can involve more sophisticated energy dissipation pathways than modern terrestrial analog settings alone would suggest.

  15. Fatigue monitoring and analysis of orthotropic steel deck considering traffic volume and ambient temperature

    Institute of Scientific and Technical Information of China (English)

    SONG; YongSheng; DING; YouLiang

    2013-01-01

    Fatigue has gradually become a serious issue for orthotropic steel deck used for long-span bridges. Two fatigue effects, namely number of stress cycles and equivalent stress amplitude, were introduced as investigated parameters in this paper. Investigation was focused on their relationships with traffic volume and ambient temperature by using 7-months fatigue monitoring data of an actual bridge. A fatigue analytical model considering temperature-induced changes in material property of asphalt pavement was established for verifying these relationships. The analysis results revealed that the number of stress cycles and equivalent stress amplitude showed a linear correlation with the traffic volume and ambient temperature, respectively, and that the rib-to-deck welded joint was much more sensitive to the traffic volume and ambient temperature than the rib-to-rib welded joint. The applicability of the code-recommended model for fatigue vehicle loading was also discussed, which revealed that the deterministic vehicle loading model requires improvement to account for significant randomness of the actual traffic conditions.

  16. Live pups from evaporatively dried mouse sperm stored at ambient temperature for up to 2 years.

    Directory of Open Access Journals (Sweden)

    Jie Liu

    Full Text Available The purpose of this study is to develop a mouse sperm preservation method based on evaporative drying. Mouse sperm were evaporatively dried and stored at 4°C and ambient temperature for 3 months to 2 years. Upon rehydration, a single sperm was injected into a mature oocyte to develop into a blastocyst after culture or a live birth after embryo transfer to a recipient female. For the samples stored at 4°C for 3, 6, 12, 18, and 24 months, the blastocyst formation rate was 61.5%, 49.1%, 31.5%, 32.2%, and 41.4%, respectively. The blastocyst rate for those stored at ambient temperature (∼22°C for 3, 6, 12, and 18 months was 57.8%, 36.2%, 33.6%, and 34.4%, respectively. Fifteen, eight and three live pups were produced from sperm stored at room temperature for 12, 18, and 24 months, respectively. This is the first report of live offspring produced from dried mouse sperm stored at ambient temperature for up to 2 years. Based on these results, we suggest that evaporative drying is a potentially useful method for the routine preservation of mouse sperm.

  17. Analyzing the impact of ambient temperature indicators on transformer life in different regions of Chinese mainland.

    Science.gov (United States)

    Bai, Cui-fen; Gao, Wen-Sheng; Liu, Tong

    2013-01-01

    Regression analysis is applied to quantitatively analyze the impact of different ambient temperature characteristics on the transformer life at different locations of Chinese mainland. 200 typical locations in Chinese mainland are selected for the study. They are specially divided into six regions so that the subsequent analysis can be done in a regional context. For each region, the local historical ambient temperature and load data are provided as inputs variables of the life consumption model in IEEE Std. C57.91-1995 to estimate the transformer life at every location. Five ambient temperature indicators related to the transformer life are involved into the partial least squares regression to describe their impact on the transformer life. According to a contribution measurement criterion of partial least squares regression, three indicators are conclusively found to be the most important factors influencing the transformer life, and an explicit expression is provided to describe the relationship between the indicators and the transformer life for every region. The analysis result is applicable to the area where the temperature characteristics are similar to Chinese mainland, and the expressions obtained can be applied to the other locations that are not included in this paper if these three indicators are known.

  18. Ambient temperature nanoelectrospray ion mobility detector for high performance liquid chromatography in determining amines.

    Science.gov (United States)

    Chen, Chuang; Hou, Keyong; Wang, Weiguo; Li, Jinghua; Li, Haiyang

    2014-09-01

    A nanoelectrospray ionization ion mobility spectrometer (nanoESI-IMS) working at ambient pressure and ambient temperature was developed as a detector of high performance liquid chromatography (HPLC) to achieve sensitive detection of amines with no derivatization and meanwhile provide another dimension of separation. The easier desolvation property of the charged droplets formed in nanoESI source enabled complete desolvation of the product ions of sixteen amines and drugs using the nanoESI-IMS at ambient temperature. Working at ambient temperature was good for suppressing the dissociation of thermal volatile ions, such as only the proton adducted molecular ions were observed for morphine in the nanoESI-IMS. Besides, the resolving power of the nanoESI-IMS also showed an increasing tendency as lowering the working temperature, an increment of 19 percent and 10 percent was observed for diethylamine and triethylamine as the temperature dropped from 92°C to 32°C. The resolving power of the nanoESI-IMS at 32°C for the 16 tested compounds was amid 33-44. With the nanoESI-IMS coupled to HPLC, a six-compound mixture including isomers was successfully separated and detected without any derivatization. And linear response ranges of 1 to 20, 0.5 to 20, and 0.8 to 20μgml(-1) and limits of detection of 0.25, 0.15, and 0.17μgml(-1) for triethylamine, diethylamine, and butylamine, respectively, were obtained with the hyphenated system. These results showed the excellent performance of the two-dimensional separation and detection method in direct qualitative and quantitative analyses of amines.

  19. Ambient Temperature Hybrid Polymer Electrolyte Based on Pvk + Pvdf-Hfp for Lithium Batteries

    Science.gov (United States)

    Michael, M. S.; Prabaharan, S. R. S.

    2002-12-01

    Proposed herein is a new ambient temperature Li+ conducting PVDF-HFP-co-polymer based hybrid polymer electrolyte with polyvinyl carbozole (PVK) as additive. The addition of the latter provides high ambient temperature electrolytic conductivity (σi) 0.7 × 10-3S/cm with an ionic transference number of 0.6, besides providing the thermoplastic flexibility to the whole matrix. The membrane is found to exhibit a wide electrochemical potential window, >4.5V against Li/Li+. When prepared properly, the membrane is dry and free standing, yet totally suitable for lithium polymer rechargeable batteries. This paper presents the preparation, microstructure and electrochemical characteristics of this new hybrid polymeric membrane. Finally, the dry polymeric electrolyte membrane has been employed in a lithium polymer cell against LT-LiCo0.8Ni0.2O2 as positive electrode and its interfacial behavior and electrochemical cycling results are presented.

  20. Evaluation of Aluminum Alloy 2050-T84 Microstructure and Mechanical Properties at Ambient and Cryogenic Temperatures

    Science.gov (United States)

    Hafley, Robert A.; Domack, Marcia S.; Hales, Stephen J.; Shenoy, Ravi N.

    2011-01-01

    Aluminum alloy 2050 is being considered for the fabrication of cryogenic propellant tanks to reduce the mass of future heavy-lift launch vehicles. The alloy is available in section thicknesses greater than that of the incumbent aluminum alloy, 2195, which will enable designs with greater structural efficiency. While ambient temperature design allowable properties are available for alloy 2050, cryogenic properties are not available. To determine its suitability for use in cryogenic propellant tanks, tensile, compression and fracture tests were conducted on 4 inch thick 2050-T84 plate at ambient temperature and at -320degF. Various metallurgical analyses were also performed in order to provide an understanding of the compositional homogeneity and microstructure of 2050.

  1. Test of oxidation behavior of sulfide ores at ambient temperature for fire control

    Institute of Scientific and Technical Information of China (English)

    WU Chao; LI Zi-jun; LI Ming; WU Guo-min

    2007-01-01

    The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on a large number of tests for a group sample of sulfide ores from a mine, some important conclusions were obtained. The results obtained by the investigation indicate that there is no general interpretation relative to the oxygen absorption and the formation products of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, the weight increment of the sulfide ore samples in the oxidation process at ambient temperature has a linear relationship with the quantity of oxygen absorption.

  2. Psychophysics of a nociceptive test in the mouse: ambient temperature as a key factor for variation.

    Directory of Open Access Journals (Sweden)

    Ivanne Pincedé

    Full Text Available BACKGROUND: The mouse is increasingly used in biomedical research, notably in behavioral neurosciences for the development of tests or models of pain. Our goal was to provide the scientific community with an outstanding tool that allows the determination of psychophysical descriptors of a nociceptive reaction, which are inaccessible with conventional methods: namely the true threshold, true latency, conduction velocity of the peripheral fibers that trigger the response and latency of the central decision-making process. METHODOLOGY/PRINCIPAL FINDINGS: Basically, the procedures involved heating of the tail with a CO(2 laser, recording of tail temperature with an infrared camera and stopping the heating when the animal reacted. The method is based mainly on the measurement of three observable variables, namely the initial temperature, the heating rate and the temperature reached at the actual moment of the reaction following random variations in noxious radiant heat. The initial temperature of the tail, which itself depends on the ambient temperature, very markedly influenced the behavioral threshold, the behavioral latency and the conduction velocity of the peripheral fibers but not the latency of the central decision-making. CONCLUSIONS/SIGNIFICANCE: We have validated a psychophysical approach to nociceptive reactions for the mouse, which has already been described for rats and Humans. It enables the determination of four variables, which contribute to the overall latency of the response. The usefulness of such an approach was demonstrated by providing new fundamental findings regarding the influence of ambient temperature on nociceptive processes. We conclude by challenging the validity of using as "pain index" the reaction time of a behavioral response to an increasing heat stimulus and emphasize the need for a very careful control of the ambient temperature, as a prevailing environmental source of variation, during any behavioral testing of

  3. Moisture Stable Ambient Temperature Ionic Liquids: Solvents for the New Millennium. 1. The Heck Reaction

    Directory of Open Access Journals (Sweden)

    Andrea Dallas

    2000-06-01

    Full Text Available In this paper we report examples of the Heck reaction in the new moisture stable ambient temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6. We have found that the yield of product is comparable with Heck reactions carried out in DMF, the conventional solvent for this reaction, and that the ionic liquid/catalyst mixture can be recycled several times.

  4. Comprehensive particle characterization of modern gasoline and diesel passenger cars at low ambient temperatures

    Science.gov (United States)

    Mathis, Urs; Mohr, Martin; Forss, Anna-Maria

    Particle measurements were performed in the exhaust of five light-duty vehicles (Euro-3) at +23, -7, and -20 °C ambient temperatures. The characterization included measurements of particle number, active surface area, number size distribution, and mass size distribution. We investigated two port-injection spark-ignition (PISI) vehicles, a direct-injection spark-ignition (DISI) vehicle, a compressed ignition (CI) vehicle with diesel particle filter (DPF), and a CI vehicle without DPF. To minimize sampling effects, particles were directly sampled from the tailpipe with a novel porous tube diluter at controlled sampling parameters. The diluted exhaust was split into two branches to measure either all or only non-volatile particles. Effect of ambient temperature was investigated on particle emission for cold and warmed-up engine. For the gasoline vehicles and the CI vehicle with DPF, the main portion of particle emission was found in the first minutes of the driving cycle at cold engine start. The particle emission of the CI vehicle without DPF was hardly affected by cold engine start. For the PISI vehicles, particle number emissions were superproportionally increased in the diameter size range from 0.1 to 0.3 μm during cold start at low ambient temperature. Based on the particle mass size distribution, the DPF removed smaller particles ( dp0.5μm). No significant effect of ambient temperature was observed when the engine was warmed up. Peak emission of volatile nanoparticles only took place at specific conditions and was poorly repeatable. Nucleation of particles was predominately observed during or after strong acceleration at high speed and during regeneration of the DPF.

  5. To flower or not to flower, a temperature-sensitive decision. Characterization of flowering responses at high ambient temperature in Arabidopsis thaliana

    NARCIS (Netherlands)

    Rodenburg, N.

    2015-01-01

    To maximize fitness, plants use environmental cues to optimize growth processes. One of the processes under strong environmental regulation is flowering. Multiple environmental factors influence flowering, including temperature. Both a continuously increased ambient temperature as well as temporary

  6. To flower or not to flower, a temperature-sensitive decision : Characterization of flowering responses at high ambient temperature in Arabidopsis thaliana

    NARCIS (Netherlands)

    Rodenburg, Nicole

    2015-01-01

    To maximize fitness, plants use environmental cues to optimize growth processes. One of the processes under strong environmental regulation is flowering. Multiple environmental factors influence flowering, including temperature. Both a continuously increased ambient temperature as well as temporary

  7. Correlations among factors of sulfide ores in oxidation process at ambient temperature

    Institute of Scientific and Technical Information of China (English)

    吴超; 李孜军; 周勃

    2004-01-01

    Spontaneous combustion is one of the serious problems in the mining of sulfide ore deposits. The relevant factors, e. G. Oxygen absorption quantity, mass increase, contents of water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process were investigated both in theory and experiment. The results from the investigation show that there is no general interpretation relation among the oxygen absorption quantity, the contents of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature.However, there is a linear relationship between the mass increase of the sulfide ore samples in the oxidation process at ambient temperature and the quantity of oxygen absorption. Therefore, the simple and cheap mass scaling method is suitable for predicting the oxygen absorption performance of sulfide ores at ambient temperature in place of the expensive and complicated chemical method used hitherto. Furthermore, combined with other items of breeding-fire test, the mass increase potential can also be used to predict the spontaneous combustion tendency of sulfide ores.

  8. Ambient maximum temperature as a function of Salmonella food poisoning cases in the Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Vladimir Kendrovski

    2011-01-01

    Full Text Available Background: Higher temperatures have been associated with higher salmonellosis notifications worldwide. Aims : The objective of this paper is to assess the seasonal pattern of Salmonella cases among humans. Material and Methods: The relationship between ambient maximum temperature and reports of confirmed cases of Salmonella in the Republic of Macedonia and Skopje during the summer months (i.e. June, July, August and September beginning in 1998 through 2008 was investigated. The monthly number of reported Salmonella cases and ambient maximum temperatures for Skopje were related to the national number of cases and temperatures recorded during the same timeframe using regression statistical analyses. The Poisson regression model was adapted for the analysis of the data. Results: While a decreasing tendency was registered at the national level, the analysis for Skopje showed an increasing tendency for registration of new salmonella cases. Reported incidents of salmonellosis, were positively associated (P<0.05 with temperature during the summer months. By increasing of the maximum monthly mean temperature of 1° C in Skopje, the salmonellosis incidence increased by 5.2% per month. Conclusions: The incidence of Salmonella cases in the Macedonian population varies seasonally: the highest values of the Seasonal Index for Salmonella cases were registered in the summer months, i.e. June, July, August and September.

  9. NEW ROOM TEMPERATURE LIQUIDS: SYNTHESIS AND CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Macaev Fliur

    2007-06-01

    Full Text Available Room temperature ionic liquids (ILs have been recognized as a new generation of solvents for “green chemistry” and represent remarkably promising classes of technologically useful and fundamentally interesting materials [1-6]. Most of them are quaternary imidazolium cations with inorganic counterions. Cation in these salts is appended to the organic group (usually saturated hydrocarbon fragments. However, some problems regarding the functionalization [2,7], coordination properties [4] of ILs still remain to be solved. It seems to us that functionalization of imidazoles by ethylcarbonitrile, allyl, 2,3-epoxypropyl fragments will lead to new properties of synthesized ILs. There are no literature data on use of 2-(1H-1-imidazolylethylcarbonitrile 4 for synthesis of imidazolium salts with ILs properties.

  10. Ambient temperature influences tolerance to plant secondary compounds in a mammalian herbivore.

    Science.gov (United States)

    Kurnath, P; Merz, N D; Dearing, M D

    2016-01-13

    Growing evidence suggests that plant secondary compounds (PSCs) ingested by mammals become more toxic at elevated ambient temperatures, a phenomenon known as temperature-dependent toxicity. We investigated temperature-dependent toxicity in the desert woodrat (Neotoma lepida), a herbivorous rodent that naturally encounters PSCs in creosote bush (Larrea tridentata), which is a major component of its diet. First, we determined the maximum dose of creosote resin ingested by woodrats at warm (28-29°C) or cool (21-22°C) temperatures. Second, we controlled the daily dose of creosote resin ingested at warm, cool and room (25°C) temperatures, and measured persistence in feeding trials. At the warm temperature, woodrats ingested significantly less creosote resin; their maximum dose was two-thirds that of animals at the cool temperature. Moreover, woodrats at warm and room temperatures could not persist on the same dose of creosote resin as woodrats at the cool temperature. Our findings demonstrate that warmer temperatures reduce PSC intake and tolerance in herbivorous rodents, highlighting the potentially adverse consequences of temperature-dependent toxicity. These results will advance the field of herbivore ecology and may hone predictions of mammalian responses to climate change.

  11. Development of CABAL glasses for use in lithium ambient-temperature batteries

    Science.gov (United States)

    Watkins, Randall D.

    1987-06-01

    Calcium-boro-aluminate (CABAL) glasses have been developed for use as electrically insulating sealing glasses in lithium ambient-temperature batteries. CABAL glasses have superior corrosion resistance in lithium/electrolyte environments relative to TA-23, and battery lifetimes are now being projected beyond 25 y. In addition, these glasses require much lower melting and sealing temperatures than TA-23. This report outlines the evolution of the CABAL glass technology at Sandia, from original composition selection to identification of the optimum CABAL-12 composition. Seal processing including commercial glass fabrication, mechanical testing, and microstructural evaluation are discussed, and the results of our initial technology transfer efforts are summarized.

  12. Effect of ambient temperature on endurance performance while wearing cross-country skiing clothing.

    Science.gov (United States)

    Sandsund, Mariann; Saursaunet, Vegard; Wiggen, Øystein; Renberg, Julie; Færevik, Hilde; van Beekvelt, Mireille C P

    2012-12-01

    This study assessed the effects of exposure to cold (-14 and -9 °C), cool (-4 and 1 °C) and moderate warm (10 and 20 °C) environments on aerobic endurance performance-related variables: maximal oxygen consumption (VO(2max)), running time to exhaustion (TTE), running economy and running speed at lactate threshold (LT). Nine male endurance athletes wearing cross-country ski racing suit performed a standard running test at six ambient temperatures in a climatic chamber with a wind speed of 5 m s(-1). The exercise protocol consisted of a 10-min warm-up period followed by four submaximal periods of 5 min at increasing intensities between 67 and 91 % of VO(2max) and finally a maximal test to exhaustion. During the time course mean skin temperature decreased significantly with reduced ambient temperatures whereas T (re) increased during all conditions. T (re) was lower at -14 °C than at -9 and 20 °C. Running economy was significantly reduced in warm compared to cool environments and was also reduced at 20 °C compared to -9 °C. Running speed at LT was significantly higher at -4 °C than at -9, 10 and 20 °C. TTE was significantly longer at -4 and 1 °C than at -14, 10 and 20 °C. No significant differences in VO(2max) were found between the various ambient conditions. The optimal aerobic endurance performance wearing a cross-country ski racing suit was found to be -4 and 1 °C, while performance was reduced under moderate warm (10 and 20 °C) and cold (-14 and -9 °C) ambient conditions.

  13. Thermal responses and perceptions under distinct ambient temperature and wind conditions.

    Science.gov (United States)

    Shimazaki, Yasuhiro; Yoshida, Atsumasa; Yamamoto, Takanori

    2015-01-01

    Wind conditions are widely recognized to influence the thermal states of humans. In this study, we investigated the relationship between wind conditions and thermal perception and energy balance in humans. The study participants were exposed for 20 min to 3 distinct ambient temperatures, wind speeds, and wind angles. During the exposure, the skin temperatures as a physiological reaction and mental reactions of the human body were measured and the energy balance was calculated based on the human thermal-load method. The results indicate that the human thermal load is an accurate indicator of human thermal states under all wind conditions. Furthermore, wind speed and direction by themselves do not account for the human thermal experience. Because of the thermoregulation that occurs to prevent heat loss and protect the core of the body, a low skin temperature was maintained and regional differences in skin temperature were detected under cool ambient conditions. Thus, the human thermal load, which represents physiological parameters such as skin-temperature change, adequately describes the mixed sensation of the human thermal experience.

  14. On exhaust emissions from petrol-fuelled passenger cars at low ambient temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Laurikko, J. [VTT Energy, Espoo (Finland). Energy Use

    1998-11-01

    The study at hand deals with regulated and unregulated exhaust emissions from petrol-fuelled cars at low ambient temperatures with present-day or near-future exhaust after treatment systems. The subject has been investigated at VTT over a decade and this report compiles data from various sub-studies carried out between the years 1993 - 1997. Each one of them viewed different aspects of the phenomenon, like determining the low-temperature response of today`s new cars employing three-way catalytic converters or assessing the long-term durability and the influence of vehicle mileage upon the low-temperature emissions performance. Within these studies, together more than 120 cars of model years from 1990 to 1997 have been tested. Most of them were normal, in-service vehicles with total mileages differing between only a few thousand kilometres for new cars up to 80,000 km or even more for the in-use vehicles. Both the US FTP75 and the European test cycle have been employed, and the ambient temperatures ranged from the baseline (+22 deg C) down to +- O deg C, -7 deg C and in some cases even to -20 deg C. The studies attested that new cars having today`s advanced emissions control systems produced fairly low levels of emissions when tested in conditions designated in the regulations that are the basis of the current new-vehicle certification. However, this performance was not necessarily attained at ambient temperatures that were below the normative range. Fairly widespread response was recorded, and cars having almost equal emissions output at baseline could produce largely deviating outcomes in low-temperature conditions. On average, CO and HC emissions increased by a factor of five to 10, depending on the ambient temperature and vehicle type. However, emissions of NO{sub x} were largely unaffected. Apart from these regulated emissions, many unregulated species were also determined, either by using traditional sampling and chromatography methods or on-line, employing

  15. Influence of variable heat transfer coefficient of fireworks and crackers on thermal explosion critical ambient temperature and time to ignition

    Directory of Open Access Journals (Sweden)

    Guo Zerong

    2016-01-01

    Full Text Available To study the effect of variable heat transfer coefficient of fireworks and crackers on thermal explosion critical ambient temperature and time to ignition, considering the heat transfer coefficient as the power function of temperature, mathematical thermal explosion steady state and unsteady-state model of finite cylindrical fireworks and crackers with complex shell structures are established based on two-dimensional steady state thermal explosion theory. The influence of variable heat transfer coefficient on thermal explosion critical ambient temperature and time to ignition are analyzed. When heat transfer coefficient is changing with temperature and in the condition of natural convection heat transfer, critical ambient temperature lessen, thermal explosion time to ignition shorten. If ambient temperature is close to critical ambient temperature, the influence of variable heat transfer coefficient on time to ignition become large. For firework with inner barrel in example analysis, the critical ambient temperature of propellant is 463.88 K and the time to ignition is 4054.9s at 466 K, 0.26 K and 450.8s less than without considering the change of heat transfer coefficient respectively. The calculation results show that the influence of variable heat transfer coefficient on thermal explosion time to ignition is greater in this example. Therefore, the effect of variable heat transfer coefficient should be considered into thermal safety evaluation of fireworks to reduce potential safety hazard.

  16. On exergy analysis of industrial plants and significance of ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rian, Berit

    2011-07-01

    The exergy analysis has been a relatively mature theory for more than 30 years. However, it is not that developed in terms of procedures for optimizing systems, which partly explains why it is not that common. Misconceptions and prejudices, even among scientists, are also partly to blame.The main objective of this work was to contribute to the development of an understanding and methodology of the exergy analysis. The thesis was mainly based on three papers, two of which provided very different examples from existing industrial systems in Norway, thus showing the societal perspective in terms of resource utilization and thermodynamics. The last paper and the following investigation were limited to certain aspects of ambient conditions. Two Norwegian operational plants have been studied, one operative for close to 30 years (Kaarstoe steam production and distribution system), while the other has just started its expected 30 years of production (Snoehvit LNG plant). In addition to mapping the current operational status of these plants, the study of the Kaarstoe steam production and distribution system concluded that the potential for increasing the thermodynamic performance by rather cautious actions was significant, whereas the study of the Snoehvit LNG plant showed the considerable profit which the Arctic location provided in terms of reduced fuel consumption. The significance of the ambient temperature led to the study of systems with two ambient bodies (i.e. ambient water and ambient air) of different temperatures, here three different systems were investigated: A regenerative steam injection gas turbine (RSTIG), a simple Linde air liquefaction plant (Air Liq) and an air-source heat pump water heater (HPWH). In particular, the effect of the chosen environment on exergy analysis was negligible for RSTIG, modest for Air Liq and critical for HPWH. It was found that the amount of exergy received from the alternative ambient body, compared to the main exergy flow of

  17. Cyclic deformation behaviour of austenitic steels at ambient and elevated temperatures

    Indian Academy of Sciences (India)

    Th Nebel; D Eifler

    2003-02-01

    The aim of the present investigation is to characterise cyclic deformation behaviour and plasticity-induced martensite formation of metastable austenitic stainless steels at ambient and elevated temperatures, taking into account the influence of the alloying elements titanium and niobium. Titanium and niobium are ferrite-stabilising elements which influence the ferrite crystallisation. Furthermore, They form carbides and/or carbonitrides and thus limit the austenite-stabilising effect of carbon and nitrogen. Several specimen batches of titanium and niobium alloyed austenite and of a pure Cr-Ni-steel for comparison were tested under stress and total strain control at a frequency of 5 Hz and triangular load-time waveforms. Stress-strain-hysteresis and temperature measurements were used at ambient temperature to characterise cyclic deformation behaviour. Plasticity-induced martensite content was detected with non-destructive magnetic measuring techniques. The experiments yield characteristic cyclic deformation curves and corresponding magnetic signals according to the actual fatigue state and the amount of martensite. Fatigue behaviour of X6CrNiTi1810 (AISI 321), X10CrNiCb189 (AISI 348) and X5CrNi1810 (AISI 304) is characterised by cyclic hardening and softening effects which are strongly influenced by specific loading conditions. Martensite formation varies with the composition, loading conditions, temperature and number of cycles.

  18. Shaped Refractory Products--Determination of Modulus of Rupture at Ambient Temperature GB/T 3001-2000

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ 1 Scope This standard specifies a method for the determination of the modulus of rupture of dense and insulating shaped refractory products at ambient temperature, under conditions of a constant rate of increase of stress.

  19. Daily ambient temperature and renal colic incidence in Guangzhou, China: a time-series analysis

    Science.gov (United States)

    Yang, Changyuan; Chen, Xinyu; Chen, Renjie; Cai, Jing; Meng, Xia; Wan, Yue; Kan, Haidong

    2016-08-01

    Few previous studies have examined the association between temperature and renal colic in developing regions, especially in China, the largest developing country in the world. We collected daily emergency ambulance dispatches (EADs) for renal colic from Guangzhou Emergency Center from 1 January 2008 to 31 December 2012. We used a distributed-lag nonlinear model in addition to the over-dispersed generalized additive model to investigate the association between daily ambient temperature and renal colic incidence after controlling for seasonality, humidity, public holidays, and day of the week. We identified 3158 EADs for renal colic during the study period. This exposure-response curve was almost flat when the temperature was low and moderate and elevated when the temperature increased over 21 °C. For heat-related effects, the significant risk occurred on the concurrent day and diminished until lag day 7. The cumulative relative risk of hot temperatures (90th percentile) and extremely hot temperatures (99th percentile) over lag days 0-7 was 1.92 (95 % confidence interval, 1.21, 3.05) and 2.45 (95 % confidence interval, 1.50, 3.99) compared with the reference temperature of 21 °C. This time-series analysis in Guangzhou, China, suggested a nonlinear and lagged association between high outdoor temperatures and daily EADs for renal colic. Our findings might have important public health significance to prevent renal colic.

  20. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Rooftop Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Bargach, Youssef [Navigant Consulting Inc., Burlington, MA (United States)

    2016-09-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for Low-Global Warming Potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants relative to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in packaged or Rooftop Unit (RTU) air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerants selection process, the test procedures, and the final results.

  1. Comparison of Waste Heat Driven and Electrically Driven Cooling Systems for a High Ambient Temperature, Off-Grid Application

    Science.gov (United States)

    2012-12-10

    pumps, and oil -free screw and lobe type compressors . However, given the capacity of the AS, the low flow rates coupled with the low density made it...D R IV EN C O O LI N G COMPARISON OF WASTE HEAT DRIVEN AND ELECTRICALLY DRIVEN COOLING SYSTEMS FOR A HIGH AMBIENT TEMPERATURE, OFF- GRID...2010 to 10-12-2012 4. TITLE AND SUBTITLE COMPARISON OF WASTE HEAT DRIVEN AND ELECTRICALLY DRIVEN COOLING SYSTEMS FOR A HIGH AMBIENT TEMPERATURE

  2. Daily means ambient temperature prediction using artificial neural network method. A case study of Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Altan Dombayci, Oemer [Department of Technical Programmes, Denizli Vocational College, Pamukkale University, 20070 Denizli (Turkey); Goelcue, Mustafa [Department of Mechanical Education, Technical Education Faculty, Pamukkale University, 20070 Denizli (Turkey)

    2009-04-15

    The objective of this paper is to develop an artificial neural network (ANN) model which can be used to predict daily mean ambient temperatures in Denizli, south-western Turkey. In order to train the model, temperature values, measured by The Turkish State Meteorological Service over three years (2003-2005) were used as training data and the values of 2006 were used as testing data. In order to determine the optimal network architecture, various network architectures were designed; different training algorithms were used; the number of neuron and hidden layer and transfer functions in the hidden layer/output layer were changed. The predictions were performed by taking different number of hidden layer neurons between 3 and 30. The best result was obtained when the number of the neurons is 6. The selected ANN model of a multi-layer consists of 3 inputs, 6 hidden neurons and 1 output. Training of the network was performed by using Levenberg-Marquardt (LM) feed-forward backpropagation algorithms. A computer program was performed under Matlab 6.5 software. For each network, fraction of variance (R{sup 2}) and root-mean squared error (RMSE) values were calculated and compared. The results show that the ANN approach is a reliable model for ambient temperature prediction. (author)

  3. Influence of Physical Activity and Ambient Temperature on Hydration: The European Hydration Research Study (EHRS

    Directory of Open Access Journals (Sweden)

    Ricardo Mora-Rodriguez

    2016-04-01

    Full Text Available This study explored the effects of physical activity (PA and ambient temperature on water turnover and hydration status. Five-hundred seventy three healthy men and women (aged 20–60 years from Spain, Greece and Germany self-reported PA, registered all food and beverage intake, and collected 24-h urine during seven consecutive days. Fasting blood samples were collected at the onset and end of the study. Food moisture was assessed using nutritional software to account for all water intake which was subtracted from daily urine volume to allow calculation of non-renal water loss (i.e., mostly sweating. Hydration status was assessed by urine and blood osmolality. A negative association was seen between ambient temperature and PA (r = −0.277; p < 0.001. Lower PA with high temperatures did not prevent increased non-renal water losses (i.e., sweating and elevated urine and blood osmolality (r = 0.218 to 0.163 all p < 0.001. When summer and winter data were combined PA was negatively associated with urine osmolality (r = −0.153; p = 0.001. Our data suggest that environmental heat acts to reduce voluntary PA but this is not sufficient to prevent moderate dehydration (increased osmolality. On the other hand, increased PA is associated with improved hydration status (i.e., lower urine and blood osmolality.

  4. Cold Ambient Temperature Promotes Nosema spp. Intensity in Honey Bees (Apis mellifera).

    Science.gov (United States)

    Retschnig, Gina; Williams, Geoffrey R; Schneeberger, Annette; Neumann, Peter

    2017-02-09

    Interactions between parasites and environmental factors have been implicated in the loss of managed Western honey bee (=HB, Apis mellifera) colonies. Although laboratory data suggest that cold temperature may limit the spread of Nosema ceranae, an invasive species and now ubiquitous endoparasite of Western HBs, the impact of weather conditions on the distribution of this microsporidian in the field is poorly understood. Here, we conducted a survey for Nosema spp. using 18 Swiss apiaries (four colonies per apiary) over a period of up to 18 months. Samples consisting of 60 workers were collected monthly from each colony to estimate Nosema spp. intensity, i.e., the number of spores in positive samples using microscopy. Ambient apiary temperature was measured daily to estimate the proportion of days enabling HB flight (>10 °C at midday). The results show that Nosema spp. intensities were negatively correlated with the proportion of days enabling HB flight, thereby suggesting a significant and unexpected positive impact of cold ambient temperature on intensities, probably via regulation of defecation opportunities for infected hosts.

  5. Cold Ambient Temperature Promotes Nosema spp. Intensity in Honey Bees (Apis mellifera

    Directory of Open Access Journals (Sweden)

    Gina Retschnig

    2017-02-01

    Full Text Available Interactions between parasites and environmental factors have been implicated in the loss of managed Western honey bee (=HB, Apis mellifera colonies. Although laboratory data suggest that cold temperature may limit the spread of Nosema ceranae, an invasive species and now ubiquitous endoparasite of Western HBs, the impact of weather conditions on the distribution of this microsporidian in the field is poorly understood. Here, we conducted a survey for Nosema spp. using 18 Swiss apiaries (four colonies per apiary over a period of up to 18 months. Samples consisting of 60 workers were collected monthly from each colony to estimate Nosema spp. intensity, i.e., the number of spores in positive samples using microscopy. Ambient apiary temperature was measured daily to estimate the proportion of days enabling HB flight (>10 °C at midday. The results show that Nosema spp. intensities were negatively correlated with the proportion of days enabling HB flight, thereby suggesting a significant and unexpected positive impact of cold ambient temperature on intensities, probably via regulation of defecation opportunities for infected hosts.

  6. Daily variations in the influence of noradrenaline on preferred ambient temperature of the Siberian hamster.

    Science.gov (United States)

    Jefimow, Małgorzata; Wojciechowski, Michał; Tegowska, Eugenia

    2003-04-01

    Daily variations in sensitivity to noradrenaline (NA) and the activation of nonshivering thermogenesis (NST) are important for survival under a potentially wide range of environmental conditions. However, little is known regarding the ability of the Siberian hamster and other species to activate NST in the day and night when they may be subjected to marked variations in environmental temperature. In this study, the effects of acclimation temperature and time of day on the behavioral thermoregulatory response to NA injections in Siberian hamsters (Phodopus sungorus) was investigated. Hamsters were acclimated for 4 weeks to 23 degrees C and a L:D 12:12 h photoperiod. After acclimation, preferred ambient temperatures (PT(a)) in saline- and NA-injected animals were measured continuously in the temperature gradient system. NA (0.6 mg/kg; s.c.) was given every 4 h while PT(a) was monitored. After NA injections there was a rapid drop in PT(a), decreasing to approximately 15 degrees C within 10-20 min after each NA injection. Following 4 weeks of acclimation to 10 degrees C and a L:D 8:16 h photoperiod, the same hamsters were re-tested in the temperature gradient system. Cold acclimation led to an accentuation in the behavioral response with a decrease in PT(a) of approximately 10 degrees C. The maximal decrease in preferred ambient temperatures was recorded during the light phase of the day and during the second part of the night. Lowering of PT(a) after NA allows for rapid dissipation of the heat from NST. Overall, the behavioral response reflects the daily changes in brown adipose tissue sensitivity to NA and thus capacity for NST.

  7. Synthesis of Asymmetrical Organic Carbonates using CO2 as a Feedstock in AgCl/Ionic Liquid System at Ambient Conditions.

    Science.gov (United States)

    Hu, Jiayin; Ma, Jun; Lu, Lu; Qian, Qingli; Zhang, Zhaofu; Xie, Chao; Han, Buxing

    2017-01-10

    Synthesis of asymmetrical organic carbonates from the renewable and inexpensive CO2 is of great importance but also challenging, especially at ambient conditions. Herein, we found that some metal salt/ionic liquid catalyst systems were highly active for the synthesis of asymmetrical organic carbonates from CO2 , propargylic alcohols, and primary alcohols. Especially, the AgCl/1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) system was very efficient for the reactions of a wide range of substrates at room temperature and atmospheric pressure, and the yields of the asymmetrical organic carbonates could approach 100 %. The catalyst system could be reused at least five times without changing its catalytic performance, and could be easily recovered and reused. A detailed study indicated that AgCl and [Bmim][OAc] catalyzed the reactions cooperatively, resulting in unique catalytic performance.

  8. Fabrication of AlN thin films on different substrates at ambient temperature

    CERN Document Server

    Cai, W X; Wu, P H; Yang, S Z; Ji, Z M

    2002-01-01

    Aluminium nitride (AlN) is very useful as a barrier in superconductor-insulator-superconductor (SIS) device or as an insulating layer in many other applications. At ambient temperature, we deposit AlN thin films onto different substrates (such as MgO, LaAlO sub 3 and Si) by using radio-frequency magnetron sputtering and pure Al target. X-ray diffraction (XRD) and PHI-scan patterns show that the films grown on MgO substrates are excellent epitaxial films with (101) orientation of a hexagonal lattice. A possible structure of the interface between the film and the substrate is suggested and discussed.

  9. On-demand Hydrogen Production from Organosilanes at Ambient Temperature Using Heterogeneous Gold Catalysts

    Science.gov (United States)

    Mitsudome, Takato; Urayama, Teppei; Kiyohiro, Taizo; Maeno, Zen; Mizugaki, Tomoo; Jitsukawa, Koichiro; Kaneda, Kiyotomi

    2016-11-01

    An environmentally friendly (“green”), H2-generation system was developed that involved hydrolytic oxidation of inexpensive organosilanes as hydrogen storage materials with newly developed heterogeneous gold nanoparticle catalysts. The gold catalyst functioned well at ambient temperature under aerobic conditions, providing efficient production of pure H2. The newly developed size-selective gold nanoparticle catalysts could be separated easily from the reaction mixture containing organosilanes, allowing an on/off-switchable H2-production by the introduction and removal of the catalyst. This is the first report of an on/off-switchable H2-production system employing hydrolytic oxidation of inexpensive organosilanes without requiring additional energy.

  10. Photocatalyst-Free and Blue Light-Induced RAFT Polymerization of Vinyl Acetate at Ambient Temperature.

    Science.gov (United States)

    Ding, Chunlai; Fan, Caiwei; Jiang, Ganquan; Pan, Xiangqiang; Zhang, Zhengbiao; Zhu, Jian; Zhu, Xiulin

    2015-12-01

    Vinyl acetate is polymerized in the living way under the irradiation of blue light-emitting diodes (LEDs) or sunlight without photocatalyst at ambient temperature. 2-(Ethoxycarbonothioyl)sulfanyl propanoate is exclusively added and acts as initiator and chain transfer agent simultaneously in the current system. Poly(vinyl acetate) with well-regulated molecular weight and narrow molecular weight distribution (Đ < 1.30) is synthesized. Near quantitative end group fidelity of polymer is demonstrated by nuclear magnetic resonance (NMR) and matrix-assisteed laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

  11. Ambient air pollution, temperature and out-of-hospital coronary deaths in Shanghai, China.

    Science.gov (United States)

    Dai, Jinping; Chen, Renjie; Meng, Xia; Yang, Changyuan; Zhao, Zhuohui; Kan, Haidong

    2015-08-01

    Few studies have evaluated the effects of ambient air pollution and temperature in triggering out-of-hospital coronary deaths (OHCDs) in China. We evaluated the associations of air pollution and temperature with daily OHCDs in Shanghai, China from 2006 to 2011. We applied an over-dispersed generalized additive model and a distributed lag nonlinear model to analyze the effects of air pollution and temperature, respectively. A 10 μg/m(3) increase in the present-day PM10, PM2.5, SO2, NO2 and CO were associated with increases in OHCD mortality of 0.49%, 0.68%, 0.88%, 1.60% and 0.08%, respectively. A 1 °C decrease below the minimum-mortality temperature corresponded to a 3.81% increase in OHCD mortality on lags days 0-21, and a 1 °C increase above minimum-mortality temperature corresponded to a 4.61% increase over lag days 0-3. No effects were found for in-hospital coronary deaths. This analysis suggests that air pollution, low temperature and high temperature may increase the risk of OHCDs.

  12. The Influence of Ambient Temperature on Green Roof R-values

    Science.gov (United States)

    Cox, Bryce Kevin

    Green roofs can be an effective and appealing way to increase the energy efficiency of buildings by providing active insulation. As plants in the green roof transpire, there is a reduction in heat flux that is conducted through the green roof. The R-value, or thermal resistance, of a green roof is an effective measurement of thermal performance because it can be easily included in building energy calculations applicable to many different buildings and situations. The purpose of this study was to determine if an increase in ambient temperature would cause an increase in the R-value of green roofs. Test trays containing green roof materials were tested in a low speed wind tunnel equipped to determine the R-value of the trays. Three different plant species were tested in this study, ryegrass (Lolium perenne), sedum (Sedum hispanicum), and vinca (Vinca minor ). For each test in this study the relative humidity was maintained at 45% and the soil was saturated with water. The trays were tested at four different ambient temperatures, ranging from room temperature to 120ºF. The resulting R-values for sedum ranged from 1.37 to 3.28 ft2hºF/BTU, for ryegrass the R-values ranged from 2.15 to 3.62 ft2hºF/BTU, and for vinca the R-values ranged from 3.15 to 5.19 ft2hºF/BTU. The average R-value for all the tests in this study was 3.20 ft2hºF/BTU. The results showed an increase in R-value with increasing temperature. Applying an ANOVA analysis to the data, the relationship between temperature and R-value for all three plant species was found to be statistically significant.

  13. Effects of shade on welfare and meat quality of grazing sheep under high ambient temperature.

    Science.gov (United States)

    Liu, H W; Cao, Y; Zhou, D W

    2012-12-01

    This study was conducted to evaluate the effects of providing shade on growth performance, welfare, and meat quality of grazing sheep under high ambient temperature. A total of 120 healthy male Ujumqin wool sheep (a local breed; BW = 18.7 ± 1.27 kg; 14 wk old) were randomly and equally divided into shaded and unshaded treatments with 3 pens per treatment. Sheep were grazed on an unshaded pastureland from 0600 to 1000 h and 1400 to 1800 h. During other times, sheep were confined in shaded or unshaded pens. Body weight was recorded on d 1 and 42 of the experiment. Rectal temperature and respiration rate were recorded on d 7, 14, 21, 28, 35, and 42. At end of the trial, sheep were blood sampled and slaughtered to collect meat samples. Respiration rate was greater (P sheep than shaded sheep on d 14, 21, 28, 35, and 42 of the trial whereas no significant differences were found on d 7. Moreover, no differences were observed in final BW, ADG, or rectal temperature throughout the trial. The pH at 24 h postmortem (pH(24)) and cooking loss were greater (P sheep. On the contrary, lightness (L*), redness (a*) and yellowness (b*) values at 24 h postmortem were lower (P sheep. The sheep in the unshaded group had a greater (P Sheep in the shaded group had lower creatine kinase activity (P sheep in the shaded group had a greater lymphocytes (LYM) count (P meat quality traits and certain stress parameters in grazing sheep reared under high ambient temperature.

  14. Estimating methane emissions from landfills based on rainfall, ambient temperature, and waste composition: The CLEEN model.

    Science.gov (United States)

    Karanjekar, Richa V; Bhatt, Arpita; Altouqui, Said; Jangikhatoonabad, Neda; Durai, Vennila; Sattler, Melanie L; Hossain, M D Sahadat; Chen, Victoria

    2015-12-01

    Accurately estimating landfill methane emissions is important for quantifying a landfill's greenhouse gas emissions and power generation potential. Current models, including LandGEM and IPCC, often greatly simplify treatment of factors like rainfall and ambient temperature, which can substantially impact gas production. The newly developed Capturing Landfill Emissions for Energy Needs (CLEEN) model aims to improve landfill methane generation estimates, but still require inputs that are fairly easy to obtain: waste composition, annual rainfall, and ambient temperature. To develop the model, methane generation was measured from 27 laboratory scale landfill reactors, with varying waste compositions (ranging from 0% to 100%); average rainfall rates of 2, 6, and 12 mm/day; and temperatures of 20, 30, and 37°C, according to a statistical experimental design. Refuse components considered were the major biodegradable wastes, food, paper, yard/wood, and textile, as well as inert inorganic waste. Based on the data collected, a multiple linear regression equation (R(2)=0.75) was developed to predict first-order methane generation rate constant values k as functions of waste composition, annual rainfall, and temperature. Because, laboratory methane generation rates exceed field rates, a second scale-up regression equation for k was developed using actual gas-recovery data from 11 landfills in high-income countries with conventional operation. The Capturing Landfill Emissions for Energy Needs (CLEEN) model was developed by incorporating both regression equations into the first-order decay based model for estimating methane generation rates from landfills. CLEEN model values were compared to actual field data from 6 US landfills, and to estimates from LandGEM and IPCC. For 4 of the 6 cases, CLEEN model estimates were the closest to actual.

  15. Rapid high-temperature synthesis of SAPO-34 nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Mahdi Dargahi; Hossein Kazemian; Mohammad Soltanieh; Sohrab Rohani; Morteza Hosseinpour

    2011-01-01

    Decreasing particle size results in larger increase of external surface area and shorter diffusion path,both reducing mass and heat transfer resistances in catalysis and sorption.A rapid high-temperature hydrothermal synthesis method was developed to synthesize uniform nanoparticles of SAPO-34 zeolite with high crystallinity.To investigate the effects of temperature and synthesis time on purity and crystallinity of the final products,the crystallization temperature was increased from 468 to 673 K while the synthesis time was decreased from 24h to 45 min.The products were characterized by XRD and SEM techniques.It was found that high temperature and short synthesis time reduce the particle size and change the morphology of the SAPO-34 final product.

  16. Room temperature synthesis of biodiesel using sulfonated graphitic carbon nitride

    Science.gov (United States)

    Baig, R. B. Nasir; Verma, Sanny; Nadagouda, Mallikarjuna N.; Varma, Rajender S.

    2016-12-01

    Sulfonation of graphitic carbon nitride (g-CN) affords a polar and strongly acidic catalyst, Sg-CN, which displays unprecedented reactivity and selectivity in biodiesel synthesis and esterification reactions at room temperature.

  17. Room temperature synthesis of biodiesel using sulfonated graphitic carbon nitride

    Science.gov (United States)

    Sulfonation of graphitic carbon nitride (g-CN) affords a polar and strongly acidic catalyst, Sg-CN, which displays unprecedented reactivity and selectivity in biodiesel synthesis and esterification reactions at room temperature.

  18. Influence of ambient temperature on whole body and segmental bioimpedance spectroscopy measurements

    Science.gov (United States)

    Medrano, G.; Bausch, R.; Ismail, A. H.; Cordes, A.; Pikkemaat, R.; Leonhardt, S.

    2010-04-01

    Bioimpedance spectroscopy (BIS) measurements are easy to implement and could be used for continuous monitoring. However, several factors (e.g. environment temperature) influence the measurements limiting the accuracy of the technology. Changes in skin temperature produced by changes in ambient temperature are related with changes in skin blood flow and skin impedance. It is assumed that skin impedance change is responsible for the error observed in whole body and segmental measurements. Measurements including body parts more distant from the torso seem to be more affected. In the present article skin and segment impedance have been performed on healthy subjects under extreme changes in environment temperature (13-39 °C). A commercial BIS device with a range between 5 kHz and 1 MHz has been used for the measurements. The results indicate that not only skin impedance, but also impedance of deeper tissue (e.g. muscle) may be responsible for the influence of environment temperature on BIS measurements. Segmental (knee-to-knee) BIS measurements show a relative change of only 2 %, while forearm and whole body impedance changed 14 % and 8 % respectively.

  19. Ambient Facile Synthesis of Gram-Scale Copper Selenide Nanostructures from Commercial Copper and Selenium Powder.

    Science.gov (United States)

    Chen, Xin Qi; Li, Zhen; Dou, Shi Xue

    2015-06-24

    Grams of copper selenides (Cu(2-x)Se) were prepared from commercial copper and selenium powders in the presence of thiol ligands by a one-pot reaction at room temperature. The resultant copper selenides are a mixture of nanoparticles and their assembled nanosheets, and the thickness of nanosheets assembled is strongly dependent on the ratio of thiol ligand to selenium powder. The resultant Cu(2-x)Se nanostructures were treated with hydrazine solution to remove the surface ligands and then explored as a potential thermoelectric candidate in comparison with commercial copper selenide powders. The research provides a novel ambient approach for preparation of Cu(2-x)Se nanocrystallines on a large scale for various applications.

  20. Impact of Montmorillonite and Calcite on Release and Adsorption of Cyanobacterial Fatty Acids at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Liu Deng; Yang Xiaofen; Wang Hongmei; Li Jihong; Su Nian

    2008-01-01

    Minerals might act as important sorbents of sedimentary organic matter and reduce biodegradation, which favors the formation of hydrocarbon source rocks in the earth's history. Since most organic matter is degraded during the sinking process, at ambient temperature, it is important to investigate the adsorption capacity of different minerals during this process, to assess the organic loss from primary productivity to sedimentary organic matter. In this study, montmorillonite and calcite have been selected to study the impact of different minerals on the release, adsorption, and deposition of cyanobacterial (Synechococcus elonpata) fatty acids (FAs) at ambient temperature. Gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) have been utilized to detect the variation in fatty acids. Primary results suggest that minerals have a different impact on dissolved organic matter. Montmorillonite can specifically enhance the release of fatty acids from cyanobacterial cells by lowering the pH values of the solution. The adsorption of the dissolved organic matter by montmorillonite will also be enhanced under a lower pH value. Conjunction of fatty acids with montmorillonite to form a complex will favor the sinking and preservation of these organics. Selective adsorption is observed among fatty acids with different carbon numbers. In contrast, calcite does not show any impact on the release and adsorption of organic matter even though it is reportedly capable of acting as a catalyst during the transformation of organic matter at high temperature. The primary data bridge a link between primary productivity and sedimentary organic matter, suggesting the relative importance of claystoncs in the formation of hydrocarbon source rocks in the earth's history.

  1. Pressure induced ionic-superionic transition in silver iodide at ambient temperature.

    Science.gov (United States)

    Han, Y H; Wang, H B; Troyan, I A; Gao, C X; Eremets, M I

    2014-01-28

    Silver iodide (AgI-V) is an archetypical ionic compound for studying the formation mechanism of a superionic state. Previous studies have proven that superionic AgI with high ionic conductivity greater than 0.1 Ω(-1)cm(-1) could only be obtained at high temperatures. We show in this paper that high pressure could also induce the superionic state in AgI even at ambient temperature. Using electrochemical impedance spectroscopy, we investigated Ag(+) ions diffusing in rock-salt structured AgI-III and KOH-type AgI-V under high pressures and directly observed the superionic state in AgI-V. The diffusion coefficient of AgI-V is ∼3.4 × 10(-4)-8.6 × 10(-4) cm(2)/s in the investigated pressure range of 12-17 GPa, comparable with those of superionic α-AgI and AgI-III'. By analyzing the half infinite length Warburg diffusion process, two parameters α and β, which closely relate to the disordered state of Ag(+) ions, have been determined and it was suggested that Ag(+) ions in AgI-V become disordered. The ionic conductivity of AgI-V is three orders of magnitude higher than that of AgI-III, and has reached around 0.1 Ω(-1)cm(-1). Evidence for all three, the diffusion coefficient, α and β, and conductivity have proven that AgI-V is a superionic conductor at ambient temperature.

  2. Thermochemical storage for ambient temperatures. Compact seasonal heat storage; Thermochemische opslag bij omgevingstemperatuur. Compacte seizoensopslag van warmte

    Energy Technology Data Exchange (ETDEWEB)

    Wemmers, A.K. [TNO Bouw en Ondergrond, Delft (Netherlands)

    2005-12-01

    The decoupling of demand and production of energy are important aspects in sustainable energy supply systems. Heat storage by commercially available techniques is realized for a temperature level higher than the ambient temperature. Heat loss is the result. By means of thermochemical storage heat can be stored more compact and on the level of ambient temperatures. [Dutch] De ontkoppeling van vraag en de opwekking van energie spelen een belangrijke rol bij de invulling van een duurzame energievoorziening. Opslag van warmte in huidige bekende technieken heeft plaats op een hoger temperatuurniveau dan de omgeving. Met warmteverlies tot gevolg. Met een nieuwe techniek, thermochemische opslag, kan compacter en op omgevingstemperatuurniveau worden opgeslagen.

  3. Rice LTG1 is involved in adaptive growth and fitness under low ambient temperature.

    Science.gov (United States)

    Lu, Guangwen; Wu, Fu-Qing; Wu, Weixun; Wang, Hong-Jun; Zheng, Xiao-Ming; Zhang, Yunhui; Chen, Xiuling; Zhou, Kunneng; Jin, Mingna; Cheng, Zhijun; Li, Xueyong; Jiang, Ling; Wang, Haiyang; Wan, Jianmin

    2014-05-01

    Low temperature (LT) is one of the most prevalent factors limiting the productivity and geographical distribution of rice (Oryza sativa L.). Although significant progress has been made in elucidating the effect of LT on seed germination and reproductive development in rice, the genetic component affecting vegetative growth under LT remains poorly understood. Here, we report that rice cultivars harboring the dominant LTG1 (Low Temperature Growth 1) allele are more tolerant to LT (15-25°C, a temperature range prevalent in high-altitude, temperate zones and high-latitude areas), than those with the ltg1 allele. Using a map-based cloning strategy, we show that LTG1 encodes a casein kinase I. A functional nucleotide polymorphism was identified in the coding region of LTG1, causing a single amino acid substitution (I357K) that is associated with the growth rate, heading date and yield of rice plants grown at LT. We present evidence that LTG1 affects rice growth at LT via an auxin-dependent process(es). Furthermore, phylogenetic analysis of this locus suggests that the ltg1 haplotype arose before the domestication of rice in tropical climates. Together, our data demonstrate that LTG1 plays an important role in the adaptive growth and fitness of rice cultivars under conditions of low ambient temperature.

  4. Preferred ambient temperature for old and young men in summer and winter.

    Science.gov (United States)

    Natsume, K; Ogawa, T; Sugenoya, J; Ohnishi, N; Imai, K

    1992-03-01

    To investigate the effects of age on thermal sensitivity, preferred ambient temperature (Tpref) was compared between old (71-76 years) and young (21-30 years) groups, each consisting of six male subjects in summer and winter. The air temperature (Ta) was set at either 20 degrees C or 40 degrees C at commencement. The subject was directed to adjust the Ta for 45 min by manipulating a remote control switch to the level at which he felt most comfortable. In the older group, the Tpref was significantly lower in trails starting at 20 degrees C than that starting at 40 degrees C in summer. The fluctuation of Tpref (temperature difference between maximum and minimum Ta during the last 10 min) was significantly wider in the older group in both summer and winter. Repetition of the same experiment on each subject showed a poorer reproducibility of Tpref in the older group than in the younger group in summer. Tympanic and esophageal temperatures of the older group kept falling throughout the trial starting at 20 degrees C in summer. These results suggest that thermal sensitivity is decreased with advancing age and that thermal perception in the elderly, especially to cold, is less sensitive in summer.

  5. Ambient temperature dependence on emission spectrum of InAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, C.Y.; Yoon, S.F. [School of Electrical and Electronic Engineering, Nanyang Technological University (Singapore); Chua, S.J. [Institute of Materials Research and Engineering, Faculty of Engineering (Singapore)

    2009-04-15

    Semiconductor superluminescent diodes (SLDs) are important broadband light source for fiber optic gyroscope and biomedical imaging. Quantum dots (QDs) have been proposed to be the best candidate for broadband light sources due to the inhomogeneous broadening of the gain spectrum as a result of the inherited size inhomogeneity of the self-assembled QD growth. In this work, the effect of ambient temperature (25-100 C) on the emission spectrum of InAs QDs with wideband emission was investigated. It was found that the full-width at half-maximum (FWHM) of the photoluminescence (PL) spectra remains more than 125 nm throughout the temperature range, and the redshift as function of temperature is approximately 0.27 meV/K. Activation energy of 270 meV is extracted from the Arrhenius plot and the PL quenching at high temperature is attributed to thermally induced carriers escaping out of the In{sub 0.15}Ga{sub 0.85}As strain-reducing layer. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. Influence of Ambient Temperature on the CO2 Emitted With Exhaust Gases of Gasoline Vehicles

    Science.gov (United States)

    Chainikov, D.; Chikishev, E.; Anisimov, I.; Gavaev, A.

    2016-08-01

    This article focuses on the regulation of CO2 emitted in the exhaust gases of gasoline vehicles. Based on comparing the world practices of restrictive measures on greenhouse gas emissions with Russian legislation, we conclude that there is a need to adjust the limits of CO2 emission taking into account the negative impact of ambient temperature on CO2 emission. The climatic conditions of many countries stipulate the use of vehicles in temperatures below zero. At the same time, the existing regulations fully take into account the temperature features of the various countries, which casts doubt on the existence of uniform emission standards for all countries. Here, we conduct an experiment on one of the most popular cars in Russia: the Mitsubishi Lancer 9. We establish that lower temperatures are correlated with larger concentrations of CO2 in the exhaust gases. We draw a conclusion about the need to account for the actual operating conditions when establishing limit values on CO2 emissions of vehicles.

  7. Multipole Electrodynamic Ion Trap Geometries for Microparticle Confinement under Standard Ambient Temperature and Pressure Conditions

    CERN Document Server

    Mihalcea, Bogdan M; Stan, Cristina; Visan, Gina T; Ganciu, Mihai; Filinov, Vladimir E; Lapitsky, Dmitry S; Deputatova, Lidiya V; Syrovatka, Roman A

    2015-01-01

    Trapping of microparticles and aerosols is of great interest for physics and chemistry. We report microparticle trapping in multipole linear Paul trap geometries, operating under Standard Ambient Temperature and Pressure (SATP) conditions. An 8-electrode and a 12-electrode linear trap geometries have been designed and tested with an aim to achieve trapping for larger number of particles and to study microparticle dynamical stability in electrodynamic fields. We report emergence of planar and volume ordered structures of the microparticles, depending on the a.c. trapping frequency and particle specific charge ratio. The electric potential within the trap was mapped using the electrolytic tank method. Particle dynamics was simulated using a stochastic Langevin equation. We emphasize extended regions of stable trapping with respect to quadrupole traps, as well as good agreement between experiment and numerical simulations.

  8. Standard test method for ambient temperature fatigue life of metallic bonded resistance strain gages

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This test method covers a uniform procedure for the determination of strain gage fatigue life at ambient temperature. A suggested testing equipment design is included. 1.2 This test method does not apply to force transducers or extensometers that use bonded resistance strain gages as sensing elements. 1.3 Strain gages are part of a complex system that includes structure, adhesive, gage, leadwires, instrumentation, and (often) environmental protection. As a result, many things affect the performance of strain gages, including user technique. A further complication is that strain gages, once installed, normally cannot be reinstalled in another location. Therefore, it is not possible to calibrate individual strain gages; performance characteristics are normally presented on a statistical basis. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices ...

  9. Atomic resolution structure of serine protease proteinase K at ambient temperature

    Science.gov (United States)

    Masuda, Tetsuya; Suzuki, Mamoru; Inoue, Shigeyuki; Song, Changyong; Nakane, Takanori; Nango, Eriko; Tanaka, Rie; Tono, Kensuke; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Yabashi, Makina; Mikami, Bunzo; Nureki, Osamu; Numata, Keiji; Iwata, So; Sugahara, Michihiro

    2017-01-01

    Atomic resolution structures (beyond 1.20 Å) at ambient temperature, which is usually hampered by the radiation damage in synchrotron X-ray crystallography (SRX), will add to our understanding of the structure-function relationships of enzymes. Serial femtosecond crystallography (SFX) has attracted surging interest by providing a route to bypass such challenges. Yet the progress on atomic resolution analysis with SFX has been rather slow. In this report, we describe the 1.20 Å resolution structure of proteinase K using 13 keV photon energy. Hydrogen atoms, water molecules, and a number of alternative side-chain conformations have been resolved. The increase in the value of B-factor in SFX suggests that the residues and water molecules adjacent to active sites were flexible and exhibited dynamic motions at specific substrate-recognition sites. PMID:28361898

  10. Ceramic coating of metal by laser heat treatment at ambient pressure and temperature

    Science.gov (United States)

    Picouet, Pierre A.; McStay, Daniel; Hunter, Catherine; Tonge, Kenneth

    2000-02-01

    Initial results for a new laser based procedure to make ceramic coatings on ferrous metals are described. The procedure is performed at ambient temperature and pressure to avoid the use of a vacuum chamber. An Nd:YAG laser beam (1064 nm) coupled to a mechanical scanner is used to produce coating. The coating precursor materials are sprayed onto the metal sample before the laser-generated heat treatment. A jet of argon gas is used to avoid oxidation of the metallic substrate. The principal ingredients of the coating precursor are sodium tetraborate and a natural clay mineral. The product is a glassy ceramic. The product has been characterized by scanning electron microscopy, optical microscopy and hardness and adhesion tests. The results indicate that the surface material is a micrometric, single layer which adheres to the metal surface.

  11. Effect of ambient temperature on species lumping for total organic gases in gasoline exhaust emissions

    Science.gov (United States)

    Roy, Anirban; Choi, Yunsoo

    2017-03-01

    Volatile organic compound (VOCs) emissions from sources often need to be compressed or "lumped" into species classes for use in emissions inventories intended for air quality modeling. This needs to be done to ensure computational efficiency. The lumped profiles are usually reported for one value of ambient temperature. However, temperature-specific detailed profiles have been constructed in the recent past - the current study investigates how the lumping of species from those profiles into different atmospheric chemistry mechanisms is affected by temperature, considering three temperatures (-18 °C, -7 °C and 24 °C). The mechanisms considered differed on the assumptions used for lumping: CB05 (carbon bond type), SAPRC (ozone formation potential) and RACM2 (molecular surrogate and reactivity weighting). In this space, four sub-mechanisms for SAPRC were considered. Scaling factors were developed for each lumped model species and mechanism in terms of moles of lumped species per unit mass. Species which showed a direct one-to-one mapping (SAPRC/RACM2) reported scaling factors that were unchanged across mechanisms. However, CB05 showed different trends since one compound often is mapped onto multiple model species, out of which the paraffinic double bond (PAR) is predominant. Temperature-dependent parameterizations for emission factors pertaining to each lumped species class and mechanism were developed as part of the study. Here, the same kind of model species showed varying lumping parameters across the different mechanisms. These differences could be attributed to differing approaches in lumping. The scaling factors and temperature-dependent parameterizations could be used to update emissions inventories such as MOVES or SMOKE for use in chemical transport modeling.

  12. The Influence of Ambient Temperature on the Susceptibility of Aedes aegypti (Diptera: Culicidae) to the Pyrethroid Insecticide Permethrin.

    Science.gov (United States)

    Whiten, Shavonn R; Peterson, Robert K D

    2016-01-01

    Insecticides are the most common strategy used for the management of mosquitoes. Changes in ambient temperature can alter the toxicity of insecticides to ectothermic organisms. Studies show organophosphate insecticides exhibit a positive correlation between ambient temperature and mortality for many insect species, and carbamate insecticides exhibit a slightly negative correlation between ambient temperature and mortality. Pyrethroid insecticides exhibit a distinctly negative correlation between increasing ambient temperature and mortality for insects. However, this relationship has not been systematically studied for adult mosquitoes. Therefore, we examined the influence of temperature on the susceptibility of adult Aedes aegypti L. (Diptera: Culicidae) when exposed to permethrin. The median lethal concentration, LC50, was estimated for adult Ae. aegypti when exposed to eight concentrations of permethrin (ranging from 0.06–0.58 ng/cm2) at each of the following temperatures—16, 23, 26, 30, 32, and 34C—for 24 h in bottle assays. The estimated LC50 for each temperature was 0.26, 0.36, 0.36, 0.45, 0.27, and 0.31 ng/cm2, respectively. Results indicated a negative correlation between temperature and mortality from 16 to 30C, a positive correlation between temperature and mortality from 30 to 32C, and a negative correlation between temperature and mortality from 32 to 34C. If mosquito populations are expanding in space and time because of increased ambient temperatures and cannot be managed as effectively with pyrethroids, the spread of mosquito-borne diseases may pose considerable additional risk to public health.

  13. Polymer Electrolyte-Based Ambient Temperature Oxygen Microsensors for Environmental Monitoring

    Science.gov (United States)

    Hunter, Gary W.; Xu, Jennifer C.; Liu, Chung-Chiun

    2011-01-01

    An ambient temperature oxygen microsensor, based on a Nafion polymer electrolyte, has been developed and was microfabricated using thin-film technologies. A challenge in the operation of Nafion-based sensor systems is that the conductivity of Nafion film depends on the humidity in the film. Nafion film loses conductivity when the moisture content in the film is too low, which can affect sensor operation. The advancement here is the identification of a method to retain the operation of the Nafion films in lower humidity environments. Certain salts can hold water molecules in the Nafion film structure at room temperature. By mixing salts with the Nafion solution, water molecules can be homogeneously distributed in the Nafion film increasing the film s hydration to prevent Nafion film from being dried out in low-humidity environment. The presence of organics provides extra sites in the Nafion film to promote proton (H+) mobility and thus improving Nafion film conductivity and sensor performance. The fabrication of ambient temperature oxygen microsensors includes depositing basic electrodes using noble metals, and metal oxides layer on one of the electrode as a reference electrode. The use of noble metals for electrodes is due to their strong catalytic properties for oxygen reduction. A conducting polymer Nafion, doped with water-retaining components and extra sites facilitating proton movement, was used as the electrolyte material, making the design adequate for low humidity environment applications. The Nafion solution was coated on the electrodes and air-dried. The sensor operates at room temperature in potentiometric mode, which measures voltage differences between working and reference electrodes in different gases. Repeat able responses to 21-percent oxygen in nitrogen were achieved using nitrogen as a baseline gas. Detection of oxygen from 7 to 21 percent has also been demonstrated. The room-temperature oxygen micro sensor developed has extremely low power

  14. Identification of the Products of Oxidation of Quercetin by Air Oxygenat Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Viktor A Utsal

    2007-03-01

    Full Text Available Oxidation of quercetin by air oxygen takes place in water and aqueous ethanol solutions under mild conditions, namely in moderately-basic media (pH ∼ 8-10 at ambient temperature and in the absence of any radical initiators, without enzymatic catalysis or irradiation of the reaction media by light. The principal reaction products are typical of other oxidative degradation processes of quercetin, namely 3,4-dihydroxy-benzoic (proto-catechuic and 2,4,6-trihydroxybenzoic (phloroglucinic acids, as well as the decarboxylation product of the latter – 1,3,5-trihydroxybenzene (phloroglucinol. In accordance with the literature data, this process involves the cleavage of the γ-pyrone fragment (ring C of the quercetin molecule by oxygen, with primary formation of 4,6-dihydroxy-2-(3,4-dihydroxybenzoyloxybenzoic acid (depside. However under such mild conditions the accepted mechanism of this reaction (oxidative decarbonylation with formation of carbon monoxide, CO should be reconsidered as preferably an oxidative decarboxylation with formation of carbon dioxide, CO2. Direct head-space analysis of the gaseous components formed during quercetin oxidation in aqueous solution at ambient temperature indicates that the ratio of carbon dioxide/carbon monoxide in the gas phase after acidification of the reaction media is ca. 96:4 %. Oxidation under these mild conditions is typical for other flavonols having OH groups at C3 (e.g., kaempferol, but it is completely suppressed if this hydroxyl group is substituted by a glycoside fragment (as in rutin, or a methyl substituent. An alternative oxidation mechanism involving the direct cleavage of the C2-C3 bond in the diketo-tautomer of quercetin is proposed.

  15. The Effect of High Ambient Temperature on the Elderly Population in Three Regions of Sweden

    Directory of Open Access Journals (Sweden)

    Joacim Rocklöv

    2010-06-01

    Full Text Available The short-term effects of high temperatures are a serious concern in the context of climate change. In areas that today have mild climates the research activity has been rather limited, despite the fact that differences in temperature susceptibility will play a fundamental role in understanding the exposure, acclimatization, adaptation and health risks of a changing climate. In addition, many studies employ biometeorological indexes without careful investigation of the regional heterogeneity in the impact of relative humidity. We aimed to investigate the effects of summer temperature and relative humidity and regional differences in three regions of Sweden allowing for heterogeneity of the effect over the scale of summer temperature. To do so, we collected mortality data for ages 65+ from Stockholm, Göteborg and Skåne from the Swedish National Board of Health and Welfare and the Swedish Meteorological and Hydrological Institute for the years 1998 through 2005. In Stockholm and Skåne on average 22 deaths per day occurred, while in Göteborg the mean frequency of daily deaths was 10. We fitted time-series regression models to estimate relative risks of high ambient temperatures on daily mortality using smooth functions to control for confounders, and estimated non-linear effects of exposure while allowing for auto-regressive correlation of observations within summers. The effect of temperature on mortality was found distributed over the same or following day, with statistically significant cumulative combined relative risk of about 5.1% (CI = 0.3, 10.1 per °C above the 90th percentile of summer temperature. The effect of high relative humidity was statistically significant in only one of the regions, as was the effect of relative humidity (above 80th percentile and temperature (above 90th percentile. In the southernmost region studied there appeared to be a significant increase in mortality with decreasing low summer temperatures that was not

  16. Influence of / ratio on rate of chloride induced corrosion of steel reinforcement and its dependence on ambient temperature

    Indian Academy of Sciences (India)

    V Živica

    2003-08-01

    The permeability of the embedding cement material for the rate of chloride induced corrosion when the ambient temperature is increased has found a dominant position. The importance of the given permeability in the process is based on the fact that it represents a factor conditioning the possibility of the escaping of the unambiguous reaction partners, oxygen and water vapour, from the system embedding cement material-steel, as the ambient temperature is increased. The resulting effect is a slowing down of the corrosion rate when the / ratio over the value 0.6 and the ambient temperature over the value 40°C are increased. Due to the similarity of the chemism of the corrosion process of steel reinforcement, independent of the action of aggressive species, the found relationships are generally valid, e.g. for the corrosion due to carbonation.

  17. Synthesis of Carbon Nanotubes by MWPCVD at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    王升高; 汪建华; 王传新; 马志彬; 满卫东

    2002-01-01

    Growth of carbon nanotubes (CNTs) at low temperature is very important to the applications of nanotubes. In this paper, under the catalytic effect of cobalt nanoparticles supported by SiO2, CNTs were synthesized by microwave plasma chemical vapor deposition (MWPCVD)below 500℃. It demonstrates that MWPCVD can be a very efficient process for the synthesis of CNTs at low temperature.

  18. Cold-start emissions of modern passenger cars at different low ambient temperatures and their evolution over vehicle legislation categories

    Science.gov (United States)

    Weilenmann, Martin; Favez, Jean-Yves; Alvarez, Robert

    The emissions of modern gasoline and diesel passenger cars are reduced by catalysts except in cold-starting. Since catalysts require a certain temperature (typically above 300 °C) to work to full efficiency, emissions are significantly higher during the warm-up phase of the car. The duration of this period and the emissions produced depend on the ambient temperature as well as on the initial temperature of the car's propulsion systems. The additional emissions during a warm-up phase, known as "cold-start extra emissions" (CSEEs) for emission inventory modelling, are mostly assessed by emission measurements at an ambient temperature of 23 °C. However, in many European countries average ambient temperatures are below 23 °C. This necessitates emission measurements at lower temperatures in order to model and assess cold-start emissions for real-world temperature conditions. This paper investigates the influence of regulated pollutants and CO 2 emissions of recent gasoline and diesel car models (Euro-4 legislation) at different ambient temperatures, 23, -7 and -20 °C. We present a survey and model of the evolution of cold-start emissions as a function of different car generations (pre-Euro-1 to Euro-4 legislations). In addition the contribution of CSEEs to total fleet running emissions is shown to highlight their increasing importance. For gasoline cars, it turns out that in average real-world driving the majority of the CO (carbon monoxide) and HC (hydrocarbon) total emissions are due to cold-start extra emissions. Moreover, the cold-start emissions increase considerably at lower ambient temperatures. In contrast, cold-start emissions of diesel cars are significantly lower than those of gasoline cars. Furthermore, the transition from Euro-3 to Euro-4 gasoline vehicles shows a trend for a smaller decline for cold-start extra emissions than for legislative limits. Particle and NO x emission of cold-starts are less significant.

  19. Effects of Ambient Temperature on Growth Performance, Blood Metabolites, and Immune Cell Populations in Korean Cattle Steers.

    Science.gov (United States)

    Kang, H J; Lee, I K; Piao, M Y; Gu, M J; Yun, C H; Kim, H J; Kim, K H; Baik, M

    2016-03-01

    Exposure to cold may affect growth performance in accordance with the metabolic and immunological activities of animals. We evaluated whether ambient temperature affects growth performance, blood metabolites, and immune cell populations in Korean cattle. Eighteen Korean cattle steers with a mean age of 10 months and a mean weight of 277 kg were used. All steers were fed a growing stage-concentrate diet at a rate of 1.5% of body weight and Timothy hay ad libitum for 8 weeks. Experimental period 1 (P1) was for four weeks from March 7 to April 3 and period 2 (P2) was four weeks from April 4 to May 1. Mean (8.7°C) and minimum (1.0°C) indoor ambient temperatures during P1 were lower (pambient temperature affects blood T cell populations. In conclusion, colder ambient temperature decreased growth and feed efficiency in Korean cattle steers. The higher circulating NEFA concentrations observed in March compared to April suggest that lipolysis may occur at colder ambient temperatures to generate heat and maintain body temperature, resulting in lower feed efficiency in March.

  20. Influence of ambient temperature and AC magnetic field on damping behavior of Fe-13Cr-2.5Mo alloy

    Science.gov (United States)

    Xu, Yong-gang; Li, Ning; Shen, Bao-luo; Hua, Hong-xing

    2007-07-01

    The damping behaviors of Fe-13Cr-2.5Mo alloy at ambient temperatures and the AC magnetic field are tested with the improved reversal torsion machine. The precipitations distributing in the annealed alloy are also observed with SEM. The results show that because the defections decrease during the annealing treatment, causing a higher damping capacity of this alloy. This damping drops linearly to 63% when the ambient temperature changes from 23 °C to 500 °C, resulting from the gradual decrease of ferromagnetism. On the other hand, the AC magnetic field causes the damping capacity to drop sharply, and finally it reaches a much lower level.

  1. Association between ambient temperature and acute myocardial infarction hospitalisations in Gothenburg, Sweden: 1985-2010.

    Directory of Open Access Journals (Sweden)

    Janine Wichmann

    Full Text Available Cardiovascular disease (CVD is the number one cause of death globally and evidence is steadily increasing on the role of non-traditional risk factors such as meteorology and air pollution. Nevertheless, many research gaps remain, such as the association between these non-traditional risk factors and subtypes of CVD, such as acute myocardial infarction (AMI. The objective of this study was to investigate the association between daily ambient temperature and AMI hospitalisations using a case-crossover design in Gothenburg, Sweden (1985-2010. A secondary analysis was also performed for out-of-hospital ischemic heart disease (IHD deaths. Susceptible groups by age and sex were explored. The entire year as well as the warm (April-September and cold periods (October-March were considered. In total 28,215 AMI hospitalisations (of 22,475 people and 21,082 out-of-hospital IHD deaths occurred during the 26-year study period. A linear exposure-response corresponding to a 3% and 7% decrease in AMI hospitalisations was observed for an inter-quartile range (IQR increase in the 2-day cumulative average of temperature during the entire year (11°C and the warm period (6°C, respectively, with and without adjustment for PM₁₀, NO₂, NOx or O₃. No heat waves occurred during the warm period. No evidence of an association in the cold period nor any association between temperature and IHD deaths in the entire year, warm or cold periods--with and without adjusting for PM₁₀, NO₂, NOx or O₃ was found. No susceptible groups, based on age or sex, were identified either. The inverse association between temperature and AMI hospitalisations (entire year and warm period in Gothenburg is in accordance with the majority of the few other studies that investigated this subtype of CVD.

  2. Ambient-temperature high damping capacity in TiPd-based martensitic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Dezhen [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Zhou, Yumei, E-mail: zhouyumei@mail.xjtu.edu.cn [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ding, Xiangdong [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Otsuka, Kazuhiro [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Lookman, Turab [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Sun, Jun [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ren, Xiaobing [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

    2015-04-24

    Shape memory alloys (SMAs) have attracted considerable attention for their high damping capacities. Here we investigate the damping behavior of Ti{sub 50}(Pd{sub 50−x}D{sub x}) SMAs (D=Fe, Co, Mn, V) by dynamic mechanical analysis. We find that these alloys show remarkably similar damping behavior. There exists a sharp damping peak associated with the B2–B19 martensitic transformation and a high damping plateau (Q{sup −1}~0.02–0.05) over a wide ambient-temperature range (220–420 K) due to the hysteretic twin boundary motion. After doping hydrogen into the above alloys, a new relaxation-type damping peak appears in the martensite phase over 270–360 K. Such a peak is considered to originate from the interaction of hydrogen atoms with twin boundaries and the corresponding damping capacity (Q{sup −1}~0.05–0.09) is enhanced by roughly twice that of the damping plateau for each alloy. Moreover, the relaxation peaks are at higher temperatures for the TiPd-based alloys (270–370 K) than for the TiNi-based alloys (190–260 K). We discuss the influence of hydrogen diffusion, mobility of twin boundaries and hydrogen–twin boundary interaction on the temperature range of the relaxation peak. Our results suggest that a martensite, with appropriate values for twinning shear and hydrogen doping level, provides a route towards developing high damping SMAs for applications in desired temperature ranges.

  3. Screening of agrochemicals in foodstuffs using low-temperature plasma (LTP) ambient ionization mass spectrometry.

    Science.gov (United States)

    Wiley, Joshua S; García-Reyes, Juan F; Harper, Jason D; Charipar, Nicholas A; Ouyang, Zheng; Cooks, R Graham

    2010-05-01

    Low-temperature plasma (LTP) permits direct ambient ionization and mass analysis of samples in their native environment with minimal or no prior preparation. LTP utilizes dielectric barrier discharges (DBDs) to create a low power plasma which is guided by gas flow onto the sample from which analytes are desorbed and ionized. In this study, the potential of LTP-MS for the detection of pesticide residues in food is demonstrated. Thirteen multi-class agricultural chemicals were studied (ametryn, amitraz, atrazine, buprofezin, DEET, diphenylamine, ethoxyquin, imazalil, isofenphos-methyl, isoproturon, malathion, parathion-ethyl and terbuthylazine). To evaluate the potential of the proposed approach, LTP-MS experiments were performed directly on fruit peels as well as on fruit/vegetable extracts. Most of the agrochemicals examined displayed remarkable sensitivity in the positive ion mode, giving limits of detection (LOD) for the direct measurement in the low picogram range. Tandem mass spectrometry (MS/MS) was used to confirm identification of selected pesticides by using for these experiments spiked fruit/vegetable extracts (QuEChERS, a standard sample treatment protocol) at levels as low as 1 pg, absolute, for some of the analytes. Comparisons of the data obtained by direct LTP-MS were made with the slower but more accurate conventional LC-MS/MS procedure. Herbicides spiked in aqueous solutions were detectable at LODs as low as 0.5 microg L(-1) without the need for any sample preparation. The results demonstrate that ambient LTP-MS can be applied for the detection and confirmation of traces of agrochemicals in actual market-purchased produce and in natural water samples. Quantitative analysis was also performed in a few selected cases and displayed a relatively high degree of linearity over four orders of magnitude.

  4. Real-World Emission of Particles from Vehicles: Volatility and the Effects of Ambient Temperature.

    Science.gov (United States)

    Wang, Jonathan M; Jeong, Cheol-Heon; Zimmerman, Naomi; Healy, Robert M; Hilker, Nathan; Evans, Greg J

    2017-03-16

    A majority of the ultrafine particles observed in real-world conditions are systematically excluded from many measurements that help to guide regulation of vehicle emissions. To investigate the impact of this exclusion, coincident near-road particle number (PN) emission factors were quantified up- and downstream of a thermodenuder during two seasonal month-long campaigns with wide-ranging ambient temperatures (-19 to +30 °C) to determine the volatile fraction of particles. During colder temperatures (20 °C). Additionally, mean PN emission factors were a factor of 3.8 higher during cold compared to warm periods. On the basis of 130 000 vehicle plumes including three additional campaigns, fleet mean emission factors were calculated for PN (8.5 × 10(14) kg-fuel(-1)), black carbon (37 mg kg-fuel(-1)), organic aerosol (51 mg kg-fuel(-1)), and particle-bound polycyclic aromatic hydrocarbons (0.7 mg kg-fuel(-1)). These findings demonstrate that significant differences exist between particles in thermally treated vehicle exhaust as compared to in real-world vehicle plumes to which populations in near-road environments are actually exposed. Furthermore, the magnitude of these differences are dependent upon season and may be more extreme in colder climates.

  5. Non-contact skin emissivity: measurement from reflectance using step change in ambient radiation temperature.

    Science.gov (United States)

    Togawa, T

    1989-02-01

    A method of estimating skin emissivity based on reflectance measurement upon transient stepwise change in the ambient radiation temperature was proposed. To effect this change, two shades at different temperatures were switched mechanically, and the change in radiation from the skin surface was recorded through an aperture for each shade by a high-resolution, fast-response radiometer having a sensitivity within the 8-14 microns range. Measurements were made on the forehead, forearm, palm and back of the hand in 10 male and 10 female subjects. No significant differences in emissivity were observed among sites and between sexes. The overall average of the skin emissivity obtained was 0.971 +/- 0.005 (SD). This result is inconsistent with most reported skin emissivity values. However, as the former studies had many inherent inadequacies, both theoretical and experimental, it is considered that most of these reported skin emissivities are unacceptable. The method proposed in this study has the following advantages: (1) relative calibration between instruments is unnecessary, (2) non-contact measurement can be achieved, and (3) each measurement can be made within one minute.

  6. THE INFLUENCE OF OBESITY AND AMBIENT TEMPERATURE ON PHYSIOLOGICAL AND OXIDATIVE RESPONSES TO SUBMAXIMAL EXERCISE

    Science.gov (United States)

    Ahn, N.

    2014-01-01

    This study investigated the effects of obesity and ambient temperature on physiological responses and markers of oxidative stress to submaximal exercise in obese and lean people. Sixteen healthy males were divided into an obese group (n=8, %fat: 27.00±3.00%) and a lean group (n=8, %fat: 13.85±2.45%). Study variables were measured during a 60 min submaximal exercise test at 60% VO2max in a neutral (21±1°C) and a cold (4±1°C) environment. Heart rate, blood lactate, rectal temperature, serum levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were measured at rest, during exercise and in recovery. Heart rate of both groups was significantly lower (P<0.05) in the cold than the warm environment, but there were no significant differences between the two groups. Serum SOD activity increased to a significantly greater extent (P<0.05) in the cold than the neutral environment, and remained elevated for longer during exercise in the obese group than the lean group. Serum MDA level during submaximal exercise was not significantly different between conditions or groups. Cold stress in exercise may challenge antioxidant defence mechanisms in obese subjects, but lipid peroxidation remains unchanged. PMID:24899779

  7. Systematic effects from an ambient-temperature, continuously-rotating half-wave plate

    CERN Document Server

    Essinger-Hileman, T; Appel, J W; Choi, S K; Crowley, K; Jarosik, N; Page, L A; Parker, L P; Raghunathan, S; Simon, S M; Staggs, S T; Visnjic, K

    2016-01-01

    We present an evaluation of systematic effects associated with a continuously-rotating, ambient-temperature half-wave plate (HWP) based on two seasons of data from the Atacama B-Mode Search (ABS) experiment located in the Atacama Desert of Chile. The ABS experiment is a microwave telescope sensitive at 145 GHz. The HWP allows for rejection of unpolarized atmospheric fluctuations and ground pickup, as well as clear separation of celestial polarization from intensity. In a previous paper, we demonstrated 30 dB rejection of atmospheric fluctuations on timescales of 500 s. Here we present our in-field evaluation of celestial (CMB plus galactic foreground) temperature-to-polarization leakage. We decompose the leakage into scalar, dipole, and quadrupole leakage terms. We report a scalar leakage of ~0.01%, consistent with model expectations and an order of magnitude smaller than other CMB experiments have reported. No significant dipole or quadruple terms are detected; we constrain each to be < 0.06% (95% confide...

  8. Systematic effects from an ambient-temperature, continuously rotating half-wave plate

    Science.gov (United States)

    Essinger-Hileman, T.; Kusaka, A.; Appel, J. W.; Choi, S. K.; Crowley, K.; Ho, S. P.; Jarosik, N.; Page, L. A.; Parker, L. P.; Raghunathan, S.; Simon, S. M.; Staggs, S. T.; Visnjic, K.

    2016-09-01

    We present an evaluation of systematic effects associated with a continuously rotating, ambient-temperature half-wave plate (HWP) based on two seasons of data from the Atacama B-Mode Search (ABS) experiment located in the Atacama Desert of Chile. The ABS experiment is a microwave telescope sensitive at 145 GHz. Here we present our in-field evaluation of celestial (Cosmic Microwave Background (CMB) plus galactic foreground) temperature-to-polarization leakage. We decompose the leakage into scalar, dipole, and quadrupole leakage terms. We report a scalar leakage of ˜0.01%, consistent with model expectations and an order of magnitude smaller than other CMB experiments have been reported. No significant dipole or quadrupole terms are detected; we constrain each to be ABS survey and focal-plane layout before any data correction such as so-called deprojection. This demonstrates that ABS achieves significant beam systematic error mitigation from its HWP and shows the promise of continuously rotating HWPs for future experiments.

  9. Electric battery cell, system and method. [ambient temperature, dithionite salt in electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, R.E.

    1979-05-15

    An ambient-temperature electric cell of primary and secondary nature, characterized by the use of the dithionite salt of an active (alkali or an alkaline earth) metal as the charging agent, is described along with processes for manufacturing and for operating it. The dithionite salt is dissolved and suspended in an anhydrous electrolyte comprised of a suitable solvent, which may also contain another salt of the same active metal and may be saturated with sulfur dioxide. To form the cell, a sealed and evacuated enclosure having a negative electrode and a positive current-gathering electrode is filled with the electrolyte and subjected to a charging current sufficient to plate the active metal onto the negative electrode, while the positive electrode is saturated with sulfur dioxide. In the case of a secondary cell, the dithionite produced upon discharge is available as a partially dissolved and suspended salt in the electrolyte. Such availability may be enhanced by a system for forced circulation of the electrolyte. In the case of a primary cell, the final cell potential and discharge characteristics may be enhanced by replacing the dithionite electrolyte with other anhydrous electrolyte solutions (e.g., sulfuryl chloride or thionyl chloride) once the lithium has been plated out. The cell is characterized by extremely low internal resistance, long shelf life, and excellent performance over a wide temperature range. 72 claims.

  10. Nocturnal loss of body reserves reveals high survival risk for subordinate great tits wintering at extremely low ambient temperatures.

    Science.gov (United States)

    Krams, Indrikis; Cīrule, Dina; Vrublevska, Jolanta; Nord, Andreas; Rantala, Markus J; Krama, Tatjana

    2013-06-01

    Winter acclimatization in birds is a complex of several strategies based on metabolic adjustment accompanied by long-term management of resources such as fattening. However, wintering birds often maintain fat reserves below their physiological capacity, suggesting a cost involved with excessive levels of reserves. We studied body reserves of roosting great tits in relation to their dominance status under two contrasting temperature regimes to see whether individuals are capable of optimizing their survival strategies under extreme environmental conditions. We predicted less pronounced loss of body mass and body condition and lower rates of overnight mortality in dominant great tits at both mild and extremely low ambient temperatures, when ambient temperature dropped down to -43 °C. The results showed that dominant great tits consistently maintained lower reserve levels than subordinates regardless of ambient temperature. However, dominants responded to the rising risk of starvation under low temperatures by increasing their body reserves, whereas subdominant birds decreased reserve levels in harsh conditions. Yet, their losses of body mass and body reserves were always lower than in subordinate birds. None of the dominant great tits were found dead, while five young females and one adult female were found dead in nest boxes during cold spells when ambient temperatures dropped down to -43 °C. The dead great tits lost up to 23.83 % of their evening body mass during cold nights while surviving individuals lost on average 12.78 % of their evening body mass. Our results show that fattening strategies of great tits reflect an adaptive role of winter fattening which is sensitive to changes in ambient temperatures and differs among individuals of different social ranks.

  11. High performance PEMFC stack with open-cathode at ambient pressure and temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Santa Rosa, D.T.; Pinto, D.G.; Silva, V.S. [SRE - Solucoes Racionais de Energia, S.A., Poligono Industrial do Alto do Ameal, Ramalhal (Portugal); Silva, R.A.; Rangel, C.M. [INETI, Unidade de Electroquimica de Materiais, Lisboa (Portugal)

    2007-12-15

    An open-air cathode proton exchange membrane fuel cell (PEMFC) was developed. This paper presents a study of the effect of several critical operating conditions on the performance of an 8-cell stack. The studied operating conditions such as cell temperature, air flow rate and hydrogen pressure and flow rate were varied in order to identify situations that could arise when the PEMFC stack is used in low-power portable PEMFC applications. The stack uses an air fan in the edge of the cathode manifolds, combining high stoichiometric oxidant supply and stack cooling purposes. In comparison with natural convection air-breathing stacks, the air dual-function approach brings higher stack performances, at the expense of having a lower use of the total stack power output. Although improving the electrochemical reactions kinetics and decreasing the polarization effects, the increase of the stack temperature lead to membrane excessive dehydration (loss of sorbed water), increasing the ohmic resistance of the stack (lower performance). The results show that the stack outputs a maximum power density of 310mW/cm{sup 2} at 790mA/cm{sup 2} when operating at ambient temperature, atmospheric air pressure, self-humidifying, air fan voltage at 5.0 V and 250 mbar hydrogen relative pressure. For the studied range of hydrogen relative pressure (150-750 mbar), it is found that the stack performance is practically not affected by this operation condition, although a slightly higher power output for 150 mbar was observed. On the other hand, it is found that the stack performance increases appreciably when operated with forced air convection instead of natural convection. Finally, the continuous fuel flow operation mode does not improve the stack performance in comparison with the hydrogen dead-end mode, in spite of being preferable to operate the stack with hydrogen flow rates above 0.20 l/min. (author)

  12. Staying cool in a changing landscape: the influence of maximum daily ambient temperature on grizzly bear habitat selection.

    Science.gov (United States)

    Pigeon, Karine E; Cardinal, Etienne; Stenhouse, Gordon B; Côté, Steeve D

    2016-08-01

    To fulfill their needs, animals are constantly making trade-offs among limiting factors. Although there is growing evidence about the impact of ambient temperature on habitat selection in mammals, the role of environmental conditions and thermoregulation on apex predators is poorly understood. Our objective was to investigate the influence of ambient temperature on habitat selection patterns of grizzly bears in the managed landscape of Alberta, Canada. Grizzly bear habitat selection followed a daily and seasonal pattern that was influenced by ambient temperature, with adult males showing stronger responses than females to warm temperatures. Cutblocks aged 0-20 years provided an abundance of forage but were on average 6 °C warmer than mature conifer stands and 21- to 40-year-old cutblocks. When ambient temperatures increased, the relative change (odds ratio) in the probability of selection for 0- to 20-year-old cutblocks decreased during the hottest part of the day and increased during cooler periods, especially for males. Concurrently, the probability of selection for 21- to 40-year-old cutblocks increased on warmer days. Following plant phenology, the odds of selecting 0- to 20-year-old cutblocks also increased from early to late summer while the odds of selecting 21- to 40-year-old cutblocks decreased. Our results demonstrate that ambient temperatures, and therefore thermal requirements, play a significant role in habitat selection patterns and behaviour of grizzly bears. In a changing climate, large mammals may increasingly need to adjust spatial and temporal selection patterns in response to thermal constraints.

  13. Surface-initiated atom transfer radical polymerization of methyl methacrylate from magnetite nanoparticles at ambient temperature.

    Science.gov (United States)

    Raghuraman, G K; Dhamodharan, R

    2006-07-01

    The synthesis of methyl methacrylate (MMA) brush from the surface of magnetite nanoparticles (core-shell structure), from initiator moieties anchored covalently to the nanoparticles, via room temperature atom transfer radical polymerization (ATRP) is described. The surface-initiated polymerization was carried out from a surface-confined initiator containing a 2-bromoisobutyrate moiety with Cu(I)Br/PMDETA catalytic system. The initiator moiety was covalently anchored to the nanoparticles via a two step modification reaction scheme. Controlled polymerization was observed if ethyl-2-bromoisobutyrate (2-EiBrB) was added as a free/sacrificial initiator. A linear increase of molecular weight and a narrow molecular weight distribution of the PMMA formed in solution, provide evidence for a controlled surface-initiated polymerization, leading to surface-attached polymer brushes under mild conditions. The grafted PMMA provides good stability and dispersibility for the nanoparticles in organic solvents.

  14. High ambient temperature increases 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy")-induced Fos expression in a region-specific manner.

    Science.gov (United States)

    Hargreaves, G A; Hunt, G E; Cornish, J L; McGregor, I S

    2007-03-16

    3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy") is a popular drug that is often taken under hot conditions at dance clubs. High ambient temperature increases MDMA-induced hyperthermia and recent studies suggest that high temperatures may also enhance the rewarding and prosocial effects of MDMA in rats. The present study investigated whether ambient temperature influences MDMA-induced expression of Fos, a marker of neural activation. Male Wistar rats received either MDMA (10 mg/kg i.p.) or saline, and were placed in test chambers for 2 h at either 19 or 30 degrees C. MDMA caused significant hyperthermia at 30 degrees C and a modest hypothermia at 19 degrees C. The 30 degrees C ambient temperature had little effect on Fos expression in vehicle-treated rats. However MDMA-induced Fos expression was augmented in 15 of 30 brain regions at the high temperature. These regions included (1) sites associated with thermoregulation such as the median preoptic nucleus, dorsomedial hypothalamus and raphe pallidus, (2) the supraoptic nucleus, a region important for osmoregulation and a key mediator of oxytocin and vasopressin release, (3) the medial and central nuclei of the amygdala, important in the regulation of social and emotional behaviors, and (4) the shell of the nucleus accumbens and (anterior) ventral tegmental area, regions associated with the reinforcing effects of MDMA. MDMA-induced Fos expression was unaffected by ambient temperature at many other sites, and was diminished at high temperature at one site (the islands of Calleja), suggesting that the effect of temperature on MDMA-induced Fos expression was not a general pharmacokinetic effect. Overall, these results indicate that high temperatures accentuate key neural effects of MDMA and this may help explain the widespread use of the drug under hot conditions at dance parties as well as the more hazardous nature of MDMA taken under such conditions.

  15. Sloths like it hot: ambient temperature modulates food intake in the brown-throated sloth (Bradypus variegatus).

    Science.gov (United States)

    Cliffe, Rebecca N; Haupt, Ryan J; Avey-Arroyo, Judy A; Wilson, Rory P

    2015-01-01

    Sloths are considered to have one of the lowest mass-specific metabolic rates of any mammal and, in tandem with a slow digestive rate, have been theorized to have correspondingly low rates of ingestion. Here, we show in a study conducted over five months, that three captive Bradypus variegatus (Brown-throated sloths) had a remarkably low mean food intake of 17 g kg(-1)day(-1) (SD 4.2). Food consumption was significantly affected by ambient temperature, with increased intake at higher temperatures. We suggest that the known fluctuation of sloth core body temperature with ambient temperature affects the rate at which gut fauna process digesta, allowing for increased rates of fermentation at higher temperatures. Since Bradypus sloths maintain a constantly full stomach, faster rates of fermentation should enhance digestive throughput, increasing the capacity for higher levels of food intake, thereby allowing increased energy acquisition at higher ambient temperatures. This contrasts with other mammals, which tend to show increased levels of food intake in colder conditions, and points to the importance of temperature in regulating all aspects of energy use in sloths.

  16. Sloths like it hot: ambient temperature modulates food intake in the brown-throated sloth (Bradypus variegatus

    Directory of Open Access Journals (Sweden)

    Rebecca N. Cliffe

    2015-04-01

    Full Text Available Sloths are considered to have one of the lowest mass-specific metabolic rates of any mammal and, in tandem with a slow digestive rate, have been theorized to have correspondingly low rates of ingestion. Here, we show in a study conducted over five months, that three captive Bradypus variegatus (Brown-throated sloths had a remarkably low mean food intake of 17 g kg−1day−1 (SD 4.2. Food consumption was significantly affected by ambient temperature, with increased intake at higher temperatures. We suggest that the known fluctuation of sloth core body temperature with ambient temperature affects the rate at which gut fauna process digesta, allowing for increased rates of fermentation at higher temperatures. Since Bradypus sloths maintain a constantly full stomach, faster rates of fermentation should enhance digestive throughput, increasing the capacity for higher levels of food intake, thereby allowing increased energy acquisition at higher ambient temperatures. This contrasts with other mammals, which tend to show increased levels of food intake in colder conditions, and points to the importance of temperature in regulating all aspects of energy use in sloths.

  17. A note on eating behaviour of dairy cows at different stocking systems - diurnal rhythm and effects of ambient temperature

    NARCIS (Netherlands)

    Taweel, H.Z.; Tas, B.M.; Smit, H.J.; Tamminga, S.; Elgersma, A.

    2006-01-01

    This experiment was aimed at studying the diurnal rhythm of dairy cows eating behaviour at different stocking systems, and quantifying the effect of daily ambient temperature on this diurnal rhythm. In two experiments carried out in the summer of 2003 in The Netherlands, eight dairy cows were offere

  18. Room-temperature carbide-derived carbon synthesis by electrochemical etching of MAX phases.

    Science.gov (United States)

    Lukatskaya, Maria R; Halim, Joseph; Dyatkin, Boris; Naguib, Michael; Buranova, Yulia S; Barsoum, Michel W; Gogotsi, Yury

    2014-05-05

    Porous carbons are widely used in energy storage and gas separation applications, but their synthesis always involves high temperatures. Herein we electrochemically selectively extract, at ambient temperature, the metal atoms from the ternary layered carbides, Ti3 AlC2 , Ti2 AlC and Ti3 SiC2 (MAX phases). The result is a predominantly amorphous carbide-derived carbon, with a narrow distribution of micropores. The latter is produced by placing the carbides in HF, HCl or NaCl solutions and applying anodic potentials. The pores that form when Ti3 AlC2 is etched in dilute HF are around 0.5 nm in diameter. This approach forgoes energy-intensive thermal treatments and presents a novel method for developing carbons with finely tuned pores for a variety of applications, such as supercapacitor, battery electrodes or CO2 capture.

  19. Influence of variable heat transfer coefficient of fireworks and crackers on thermal explosion critical ambient temperature and time to ignition

    OpenAIRE

    Guo Zerong; Xia Quan; Yan Peiyu; Du Zhiming

    2016-01-01

    To study the effect of variable heat transfer coefficient of fireworks and crackers on thermal explosion critical ambient temperature and time to ignition, considering the heat transfer coefficient as the power function of temperature, mathematical thermal explosion steady state and unsteady-state model of finite cylindrical fireworks and crackers with complex shell structures are established based on two-dimensional steady state thermal explosion theory. T...

  20. Moderate Temperature Synthesis of Mesoporous Carbon

    KAUST Repository

    Dua, Rubal

    2013-01-03

    Methods and composition for preparation of mesoporous carbon material are provided. For example, in certain aspects methods for carbonization and activation at selected temperature ranges are described. Furthermore, the invention provides products prepared therefrom.

  1. Pelage insulation, litter size, and ambient temperature impact maternal energy intake and offspring development during lactation.

    Science.gov (United States)

    Paul, Matthew J; Tuthill, Christiana; Kauffman, Alexander S; Zucker, Irving

    2010-05-11

    Energy balance during lactation critically influences survival and growth of a mother's offspring, and hence, her reproductive success. Most experiments have investigated the influence of a single factor (e.g., ambient temperature [T(a)] or litter size) on the energetics of lactation. Here, we determined the impact of multiple interventions, including increased conductive heat loss consequent to dorsal fur removal, cold exposure (T(a) of 5 degrees C versus 23 degrees C), and differential lactational load from litters of different sizes (2 or 4 pups), on maternal energy balance and offspring development of Siberian hamsters (Phodopus sungorus). Lower T(a), fur removal, and larger litters were associated with increased maternal food consumption. Females exposed to multiple challenges (e.g., both fur loss and lower T(a)) ate substantially more food than those exposed to a single challenge, with no apparent ceiling to elevated food intake (increases up to 538%). Thus, energy intake of dams under these conditions does not appear to be limited by feeding behavior or the size of the digestive tract. Housing at 5 degrees C attenuated pup weight gain and increased pup mortality to more than 5 times that of litters housed at 23 degrees C. Increases in the dam's conductive heat loss induced by fur removal did not affect pup weight gain or survival, suggesting that effects of low T(a) on pup weight gain and survival reflect limitations in the pups' ability to ingest or incorporate energy.

  2. Fatty acid composition of ewe milk as affected by solar radiation and high ambient temperature.

    Science.gov (United States)

    Sevi, Agostino; Rotunno, Taddeo; Di Roberto, Caterina; Muscio, Antonio

    2002-05-01

    Forty lactating Comisana ewes were either exposed to or protected from solar radiation and fed either in the morning or afternoon during summer in a Mediterranean climate. Individual milk samples were taken on days 7, 21 and 42 of the study period to determine fatty acid composition by gas chromatography. Exposure to solar radiation resulted in higher proportions of short-chain and saturated fatty acids in milk, primarily because of increased contents of caproic, capric, lauric, myristic and stearic acids (by 3-18%), and decreased contents of oleic, linoleic and linolenic acids (by 2-9%). As a consequence, the long to short chain and the unsaturated to saturated fatty acid ratios were significantly higher by 4 and 13% respectively in the milk of the protected ewes compared with that of the exposed animals. Provision of shade also led to an increase in the 18:0+18:1 to 16:0 ratio, and to a decrease in the 12:0 + 14:0 + 16:0 fatty acid group, which are regarded as reliable indexes of the nutritional property of dietary fat in reducing cholesterol levels in human plasma. Feeding time had little impact on milk fat. Our findings suggest that high ambient temperature may markedly modify the lipid composition of ewe milk and that provision of shade, but not feeding management, can improve the milk fatty acid profile in dairy sheep raised in hot climates.

  3. Examination of design options for 35 Ah ambient temperature Li-TiS sub 2 cells

    Science.gov (United States)

    Shen, D. H.; Rao, S. S.; Yen, S. P. S.; Somoano, R. B.

    1986-01-01

    The Jet Propulsion Laboratory is actively engaged in the development of ambient temperature rechargable lithium cells for future NASA geosynchronous Earth orbit (GEO) missions. To achieve these ambitious goals, Li-TiS2, Li-MoS3, and Li-V6O13 systems were examined in detail. Among these three, the Li-TiS2 system has shown the longest life cycle and highest rate capability. Experimental Li-TiS2 batteries (10.5 V, 0.4 Ah) developed in-house have completed eight simulated and accelerated GEO seasons successfully. Inview of the encouraging results, the design options were examined for a scaled-up Li-TiS2 cell. It is hoped that the results of these studies will provide guidelines for prioritizing the research efforts and guiding the selection of optimized materials. Designs for 35 Ah Li-TiS2 cell were examined because present day geosynchronous satellites are powered by batteries of 35 Ah capacity. A computer program was developed to evaluate the influence of various design parameters on the specific energy and the rate capability of the cells.

  4. Activated carbon catalyzed persulfate oxidation of Azo dye acid orange 7 at ambient temperature.

    Science.gov (United States)

    Yang, Shiying; Yang, Xin; Shao, Xueting; Niu, Rui; Wang, Leilei

    2011-02-15

    Persulfate (PS) oxidative degradation of azo dye acid orange 7 (AO7) in an aqueous solution was studied in the presence of suspended granular activated carbon (GAC) at ambient temperature (e.g., 25°C). It was observed that there existed a remarkable synergistic effect in the GAC/PS combined system. Higher PS concentration and GAC dosage resulted in higher AO7 degrading rates. Near-neutral was the optimal initial pH. Adsorption had an adverse effect on AO7 degradation. AO7 had not only a good decolorization, but a good mineralization. The decomposition of PS followed a first-order kinetics behavior both in the presence and in the absence of AO7. Radical mechanism was studied and three radical scavengers (methanol (MA), tert-butanol (TBA), phenol) were used to determine the kind of major active species taking part in the degradation of AO7 and the location of degradation reaction. It was assumed that the degradation of AO7 did not occur in the liquid phase, but in the porous bulk and boundary layer on the external surface of GAC. SO(4)(-•) or HO•, generated on or near the surface of GAC, played a major role in the AO7 degradation. Finally, the recovery performance of GAC was studied through the GAC reuse experiments.

  5. Strength and Density of Geopolymer Mortar Cured at Ambient Temperature for Use as Repair Material

    Science.gov (United States)

    Warid Wazien, A. Z.; Bakri Abdullah, Mohd Mustafa Al; Abd. Razak, Rafiza; Mohd Remy Rozainy, M. A. Z.; Faheem Mohd Tahir, Muhammad

    2016-06-01

    Geopolymers produced by synthesizing aluminosilicate source materials with an alkaline activator solution promised an excellent properties akin to the existing construction material. This study focused on the effect of various binder to sand ratio on geopolymer mortar properties. Mix design of geopolymer mortar was produced using NaOH concentration of 12 molars, ratio of fly ash/alkaline activator and ratio Na2SiO3/NaOH of 2.0 and 2.5 respectively. Samples subsequently ware cured at ambient temperature. The properties of geopolymer mortar were analysed in term of compressive strength and density at different period which are on the 3rd and 7th day of curing. Experimental results revealed that the addition of sand slightly increase the compressive strength of geopolymer. The optimum compressive strength obtained was up to 31.39 MPa on the 7th day. The density of geopolymer mortar was in the range between 2.0 g/cm3 to 2.23 g/cm3. Based on this findings, the special properties promoted by geopolymer mortar display high potential to be implemented in the field of concrete patch repair.

  6. Male weasels decrease activity and energy expenditure in response to high ambient temperatures.

    Directory of Open Access Journals (Sweden)

    Karol Zub

    Full Text Available The heat dissipation limit (HDL hypothesis suggests that the capacity of endotherms to dissipate body heat may impose constraints on their energy expenditure. Specifically, this hypothesis predicts that endotherms should avoid the detrimental consequences of hyperthermia by lowering their energy expenditure and reducing their activity in response to high ambient temperatures (T(a. We used an extensive data set on the daily energy expenditure (DEE, n = 27 and the daily activity time (AT, n = 48 of male weasels (Mustela nivalis during the spring and summer breeding season to test these predictions. We found that T(a was related in a "hump-shaped" (i.e. convex manner to AT, DEE, resting metabolic rate (RMR and metabolic scope (the ratio of DEE to RMR. These results support the HDL hypothesis because in response to warm Tas male weasels reduced their AT, DEE, and RMR. Although the activity and energy expenditure of large endotherms are most likely to be constrained in response to warm Tas because they are less able to dissipate heat, our results suggest that small endotherms may also experience constraints consistent with the HDL hypothesis.

  7. Short-term preservation of porcine oocytes in ambient temperature: novel approaches.

    Directory of Open Access Journals (Sweden)

    Cai-Rong Yang

    Full Text Available The objective of this study was to evaluate the feasibility of preserving porcine oocytes without freezing. To optimize preservation conditions, porcine cumulus-oocyte complexes (COCs were preserved in TCM-199, porcine follicular fluid (pFF and FCS at different temperatures (4°C, 20°C, 25°C, 27.5°C, 30°C and 38.5°C for 1 day, 2 days or 3 days. After preservation, oocyte morphology, germinal vesicle (GV rate, actin cytoskeleton organization, cortical granule distribution, mitochondrial translocation and intracellular glutathione level were evaluated. Oocyte maturation was indicated by first polar body emission and spindle morphology after in vitro culture. Strikingly, when COCs were stored at 27.5°C for 3 days in pFF or FCS, more than 60% oocytes were still arrested at the GV stage and more than 50% oocytes matured into MII stages after culture. Almost 80% oocytes showed normal actin organization and cortical granule relocation to the cortex, and approximately 50% oocytes showed diffused mitochondria distribution patterns and normal spindle configurations. While stored in TCM-199, all these criteria decreased significantly. Glutathione (GSH level in the pFF or FCS group was higher than in the TCM-199 group, but lower than in the non-preserved control group. The preserved oocytes could be fertilized and developed to blastocysts (about 10% with normal cell number, which is clear evidence for their retaining the developmental potentiality after 3d preservation. Thus, we have developed a simple method for preserving immature pig oocytes at an ambient temperature for several days without evident damage of cytoplasm and keeping oocyte developmental competence.

  8. Temperature-induced volatility of molecular markers in ambient airborne particulate matter

    Directory of Open Access Journals (Sweden)

    C. R. Ruehl

    2010-08-01

    Full Text Available Molecular markers are organic compounds used to represent known sources of particulate matter (PM in statistical source apportionment studies. The utility of molecular markers depends on, among other things, their ability to represent PM volatility under realistic atmospheric conditions. We measured the particle-phase concentrations and temperature-induced volatility of commonly-used molecular markers in California's heavily polluted San Joaqin Valley. Concentrations of elemental carbon, organic carbon, levoglucosan, and polycyclic aromatic hydrocarbons were not reduced by mild (~10 K heating. In contrast, both hopane/sterane and n-alkane concentrations were reduced, especially during the summer sampling events at the urban site. These results suggest that hopanes and steranes have effective saturation concentrations ~1 μg m−3, and therefore can be considered semi-volatile in realistic ambient conditions. The volatility behavior of n-alkanes during the urban summer is consistent with that predicted for absorption by suberic acid (a C8 diacid using a group contribution modelling method. Observations can also be matched by an absorbent whose composition is based on recently-obtained high-resolution aerosol mass spectrometer factors (approximately 33% "hydrocarbon-like" and 67% oxygenated organic aerosol. The diminished volatility of the n-alkanes, hopanes, and steranes during rural and/or winter experiments could be explained by a more oxygenated absorbing phase along with a non-absorptive partitioning mechanism, such as adsorption to soot. This suggests that the temperature-induced volatility of large hydrocarbons in PM is most important if a relatively non-polar absorbing organic phase exists. While the activity coefficients of most organic aerosol compounds may be close to unity, the assumption of ideality for large hydrocarbons (e.g., hopanes may result in large errors in partitioning calculations.

  9. Entrainment of the circadian clock by daily ambient temperature cycles in the camel (Camelus dromedarius).

    Science.gov (United States)

    El Allali, Khalid; Achaâban, Mohamed R; Bothorel, Béatrice; Piro, Mohamed; Bouâouda, Hanan; El Allouchi, Morad; Ouassat, Mohammed; Malan, André; Pévet, Paul

    2013-06-01

    In mammals the light-dark (LD) cycle is known to be the major cue to synchronize the circadian clock. In arid and desert areas, the camel (Camelus dromedarius) is exposed to extreme environmental conditions. Since wide oscillations of ambient temperature (Ta) are a major factor in this environment, we wondered whether cyclic Ta fluctuations might contribute to synchronization of circadian rhythms. The rhythm of body temperature (Tb) was selected as output of the circadian clock. After having verified that Tb is synchronized by the LD and free runs in continuous darkness (DD), we submitted the animals to daily cycles of Ta in LL and in DD. In both cases, the Tb rhythm was entrained to the cycle of Ta. On a 12-h phase shift of the Ta cycle, the mean phase shift of the Tb cycle ranged from a few hours in LD (1 h by cosinor, 4 h from curve peaks) to 7-8 h in LL and 12 h in DD. These results may reflect either true synchronization of the central clock by Ta daily cycles or possibly a passive effect of Ta on Tb. To resolve the ambiguity, melatonin rhythmicity was used as another output of the clock. In DD melatonin rhythms were also entrained by the Ta cycle, proving that the daily Ta cycle is able to entrain the circadian clock of the camel similar to photoperiod. By contrast, in the presence of a LD cycle the rhythm of melatonin was modified by the Ta cycle in only 2 (or 3) of 7 camels: in these specific conditions a systematic effect of Ta on the clock could not be evidenced. In conclusion, depending on the experimental conditions (DD vs. LD), the daily Ta cycle can either act as a zeitgeber or not.

  10. Small-capacity valve-regulated lead/acid battery with long life at high ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hatanaka, T.; Maeda, M.; Iwata, M. [Battery Development Center, Japan Storage Battery, Kyoto (Japan)

    1998-05-18

    Valve-regulated lead/acid (VRLA) batteries are widely used as back-up power sources for telecommunications and UPS. These applications require high-reliability under severe environmental conditions. To meet this demand, the authors` company have developed small capacity (12 V, 15-65 A h at C{sub 20}/20 rate), long-life VRLA batteries which can endure high ambient temperature. These batteries make use of a new alloy and grid design which has improved resistance to corrosion at the positive plate, while at the same time reduce float current at high temperature. As a result, these batteries have a life expectancy of 13 years at 25 C, and inhibited thermal runaway even under ambient temperatures up to 75 C. The batteries can be installed in outdoor and underground environments. (orig.)

  11. Combustion and Plasma Synthesis of High-Temperature Materials

    Science.gov (United States)

    Munir, Z. A.; Holt, J. B.

    1997-04-01

    KEYNOTE ADDRESS. Self-Propagating High-Temperature Synthesis: Twenty Years of Search and Findings (A. Merzhanov). SOLID-STATE COMBUSTION SYNTHESIS. Recent Progress in Combustion Synthesis of High-Performance Materials in Japan (M. Koizumi & Y. Miyamoto). Modeling and Numerical Computation of a Nonsteady SHS Process (A. Bayliss & B. Matkowsky). New Models of Quasiperiodic Burning in Combustion Synthesis (S. Margolis, et al.). Modeling of SHS Operations (V. Hlavacek, et al.). Combustion Theory for Sandwiches of Alloyable Materials (R. Armstrong & M. Koszykowski). Observations on the Combustion Reaction Between Thin Foils of Ni and Al (U. Anselmi-Tamburini & Z. Munir). Combustion Synthesis of Intermetallic Compounds (Y. Kaieda, et al.). Combustion Synthesis of Nickel Aluminides (B. Rabin, et al.). Self-Propagating High-Temperature Synthesis of NiTi Intermetallics (H. Yi & J. Moore). Shock-Induced Chemical Synthesis of Intermetallic Compounds (S. Work, et al.). Advanced Ceramics Via SHS (T. DeAngelis & D. Weiss). In-Situ Formation of SiC and SiC-C Blocked Solids by Self-Combustion Synthesis (S. Ikeda, et al.). Powder Purity and Morphology Effects in Combustion-Synthesis Reactions (L. Kecskes, et al.). Simultaneous Synthesis and Densification of Ceramic Components Under Gas Pressure by SHS (Y. Miyamoto & M. Koizumi). The Use of Self-Propagating High-Temperature Synthesis of High-Density Titanium Diboride (P. Zavitsanos, et al.). Metal--Ceramic Composite Pipes Produced by a Centrifugal-Thermit Process (O. Odawara). Simultaneous Combustion Synthesis and Densification of AIN (S. Dunmead, et al.). Fabrication of a Functionally Gradient Material by Using a Self-Propagating Reaction Process (N. Sata, et al.). Combustion Synthesis of Oxide-Carbide Composites (L. Wang, et al.). Heterogeneous Reaction Mechanisms in the Si-C System Under Conditions of Solid Combustion (R. Pampuch, et al.). Experimental Modeling of Particle-Particle Interactions During SHS of TiB2 -Al2O3 (K. Logan

  12. Multi-Temperature Zone, Droplet-based Microreactor for Increased Temperature Control in Nanoparticle Synthesis

    KAUST Repository

    Erdem, E. Yegân

    2013-12-12

    Microreactors are an emerging technology for the controlled synthesis of nanoparticles. The Multi-Temperature zone Microreactor (MTM) described in this work utilizes thermally isolated heated and cooled regions for the purpose of separating nucleation and growth processes as well as to provide a platform for a systematic study on the effect of reaction conditions on nanoparticle synthesis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Solution-phase synthesis of nanomaterials at low temperature

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This paper reviews the solution-phase synthesis of nanoparticles via some routes at low temperatures, such as room temperature route, wave-assisted synthesis (γ-irradiation route and sonochemical route), directly heating at low temperatures, and hydrothermal/solvothermal methods. A number of strategies were developed to control the shape, the size, as well as the dispersion of nanostructures. Using diethylamine or n-butylamine as solvent, semiconductor nanorods were yielded. By the hydrothermal treatment of amorphous colloids, Bi2S3 nanorods and Se nanowires were obtained. CdS nanowires were prepared in the presence of polyacrylamide. ZnS nanowires were obtained using liquid crystal. The polymer poly (vinyl acetate) tubule acted as both nanoreactor and template for the CdSe nanowire growth. Assisted by the surfactant of sodium dodecyl benzenesulfonate (SDBS), nickel nanobelts were synthesized. In addition, Ag nanowires, Te nanotubes and ZnO nanorod arrays could be prepared without adding any additives or templates.

  14. Product engineering by high-temperature flame synthesis

    DEFF Research Database (Denmark)

    Johannessen, Tue; Johansen, Johnny; Mosleh, Majid;

    High-temperature flame processes can be applied as a tool for chemical product engineering. The general principle behind flame synthesis is the decomposition/oxidation of evaporated metal-precursors in a flame, thereby forming metal oxide monomers which nucleate, aggregate, and - to some extent...... product gas can be applied directly in additional product engineering concepts. A brief overview of on-going product developments and product engineering projects is outlined below. These projects, which are all founded on flame synthesis of nano-structured materials, include: • Preparation of catalyzed...

  15. A Combined State of Charge Estimation Method for Lithium-Ion Batteries Used in a Wide Ambient Temperature Range

    Directory of Open Access Journals (Sweden)

    Fei Feng

    2014-05-01

    Full Text Available Ambient temperature is a significant factor that influences the characteristics of lithium-ion batteries, which can produce adverse effects on state of charge (SOC estimation. In this paper, an integrated SOC algorithm that combines an advanced ampere-hour counting (Adv Ah method and multistate open-circuit voltage (multi OCV method, denoted as “Adv Ah + multi OCV”, is proposed. Ah counting is a simple and general method for estimating SOC. However, the available capacity and coulombic efficiency in this method are influenced by the operating states of batteries, such as temperature and current, thereby causing SOC estimation errors. To address this problem, an enhanced Ah counting method that can alter the available capacity and coulombic efficiency according to temperature is proposed during the SOC calculation. Moreover, the battery SOCs between different temperatures can be mutually converted in accordance with the capacity loss. To compensate for the accumulating errors in Ah counting caused by the low precision of current sensors and lack of accurate initial SOC, the OCV method is used for calibration and as a complement. Given the variation of available capacities at different temperatures, rated/non-rated OCV–SOCs are established to estimate the initial SOCs in accordance with the Ah counting SOCs. Two dynamic tests, namely, constant- and alternated-temperature tests, are employed to verify the combined method at different temperatures. The results indicate that our method can provide effective and accurate SOC estimation at different ambient temperatures.

  16. Cobalt promoted copper manganese oxide catalysts for ambient temperature carbon monoxide oxidation.

    Science.gov (United States)

    Jones, Christopher; Taylor, Stuart H; Burrows, Andrew; Crudace, Mandy J; Kiely, Christopher J; Hutchings, Graham J

    2008-04-14

    Low levels of cobalt doping (1 wt%) of copper manganese oxide enhances its activity for carbon monoxide oxidation under ambient conditions and the doped catalyst can display higher activity than current commercial catalysts.

  17. Reactor Design for CO2 Photo-Hydrogenation toward Solar Fuels under Ambient Temperature and Pressure

    Directory of Open Access Journals (Sweden)

    Chun-Ying Chen

    2017-02-01

    Full Text Available Photo-hydrogenation of carbon dioxide (CO2 is a green and promising technology and has received much attention recently. This technique could convert solar energy under ambient temperature and pressure into desirable and sustainable solar fuels, such as methanol (CH3OH, methane (CH4, and formic acid (HCOOH. It is worthwhile to mention that this direction can not only potentially depress atmospheric CO2, but also weaken dependence on fossil fuel. Herein, 1 wt % Pt/CuAlGaO4 photocatalyst was successfully synthesized and fully characterized by ultraviolet-visible light (UV-vis spectroscopy, X-ray diffraction (XRD, Field emission scanning electron microscopy using energy dispersive spectroscopy analysis (FE-SEM/EDS, transmission electron microscopy (TEM, X-ray photoelectron spectroscopy (XPS, and Brunauer-Emmett-Teller (BET, respectively. Three kinds of experimental photo-hydrogenation of CO2 in the gas phase, liquid phase, and gas-liquid phase, correspondingly, were conducted under different H2 partial pressures. The remarkable result has been observed in the gas-liquid phase. Additionally, increasing the partial pressure of H2 would enhance the yield of product. However, when an extra amount of H2 is supplied, it might compete with CO2 for occupying the active sites, resulting in a negative effect on CO2 photo-hydrogenation. For liquid and gas-liquid phases, CH3OH is the major product. Maximum total hydrocarbons 8.302 µmol·g−1 is achieved in the gas-liquid phase.

  18. Estrous cycle fluctuations in sex and ingestive behavior are accentuated by exercise or cold ambient temperatures.

    Science.gov (United States)

    Abdulhay, Amir; Benton, Noah A; Klingerman, Candice M; Krishnamoorthy, Kaila; Brozek, Jeremy M; Schneider, Jill E

    2014-06-01

    This article is part of a Special Issue "Energy Balance". In female Syrian hamsters (Mesocricetus auratus), low circulating levels of ovarian steroids are associated with increased food hoarding and decreased sexual motivation, but these effects are exaggerated in food-restricted females. To determine whether cold ambient temperature has the same effects as food restriction, groups of hamsters were fed ad libitum while they were housed at either 5 °C or 22 °C, and then tested for behavior for 90 min on each day of the estrous cycle. In females housed at 22 °C, high levels of sexual motivation and low levels of food hoarding were seen every day of the estrous cycle. In females housed at 5 °C, high levels of sexual motivation were restricted to the periovulatory day. On the three nonestrous days, these females showed high levels of food hoarding, but not food intake. A separate cohort of females were provided with access to running wheels and housed at 22 °C. They showed high levels of sexual motivation restricted to the periovulatory day, similar to the pattern of sexual motivation seen in cold-housed females. Unlike cold-housed females, those with running wheels showed low levels of food hoarding and high levels of food intake. Food restriction, cold housing, and access to wheels had no significant effect on plasma estradiol or progesterone concentrations, but significantly decreased plasma leptin concentrations. All three energetic challenges unmask estrous cycle fluctuations in sexual motivation that are obscured in laboratory conditions, i.e., isolation in a small cage with an overabundance of food.

  19. High ambient temperature reverses hypothalamic MC4 receptor overexpression in an animal model of anorexia nervosa.

    Science.gov (United States)

    Gutiérrez, E; Churruca, I; Zárate, J; Carrera, O; Portillo, M P; Cerrato, M; Vázquez, R; Echevarría, E

    2009-04-01

    The potential involvement of the melanocortin system in the beneficial effects of heat application in rats submitted to activity-based anorexia (ABA), an analogous model of anorexia nervosa (AN), was studied. Once ABA rats had lost 20% of body weight, half of the animals were exposed to a high ambient temperature (HAT) of 32 degrees C, whereas the rest were maintained at 21 degrees C. Control sedentary rats yoked to ABA animals received the same treatment. ABA rats (21 degrees C) showed increased Melanocortin 4 (MC4) receptor and Agouti gene Related Peptide (AgRP) expression, and decreased pro-opiomelanocortin (POMC) mRNA levels (Real Time PCR), with respect to controls. Heat application increased weight gain and food intake, and reduced running rate in ABA rats, when compared with ABA rats at 21 degrees C. However, no changes in body weight and food intake were observed in sedentary rats exposed to heat. Moreover, heat application reduced MC4 receptor, AgRP and POMC expression in ABA rats, but no changes were observed in control rats. These results indicate that hypothalamic MC4 receptor overexpression could occur on the basis of the characteristic hyperactivity, weight loss, and self-starvation of ABA rats, and suggest the involvement of hypothalamic melanocortin neural circuits in behavioural changes shown by AN patients. Changes in AgRP and POMC expression could represent an adaptative response to equilibrate energy balance. Moreover, the fact that HAT reversed hypothalamic MC4 receptor overexpression in ABA rats indicates the involvement of brain melanocortin system in the reported beneficial effects of heat application in AN. A combination of MC4 receptor antagonists and heat application could improve the clinical management of AN.

  20. Experimental Investigation of the Effect of Change in Ambient Air Temperature on Power Consumption of Domestic Refrigerators

    Directory of Open Access Journals (Sweden)

    J. A. Olorunmaiye

    2012-12-01

    Full Text Available One of the manifestations of climate change is increase.in ambient air temperature usually referred to as global warming. For sustainable development in a country, there is need to identify impacts of climate change and the necessary adaptation and mitigation strategies to adopt. To simulate the effect of global warming on the power consumption of refrigerators, a (model No. 150 THERMOCOOL refrigerator filled with twenty-five 750cl packaged water bottleswas run in an air-conditioned room, in a room with the air-conditioner switched off and near an oven in a bakery. The electric power consumption of the refrigerator was measured using "Watts up?.net" Watt meter and the ambient temperature was measured using FLUKE temperature/humidity meter. The average hourly energy consumption of the refrigerator operating at mean ambient temperatures of 25.4°C, 30.7oC, 38.8°C were 93.844 Wh, 100.32 Wh and 105.08 Wh respectively. Some possible ways to reduce the increase in power consumption of refrigerators due to global warming include using compressors of higher efficiency and condensers of greater effectiveness.

  1. Structural Studies of NH4-exchanged Natrolites at Ambient Conditions and High Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Y Lee; D Seoung; Y Jang; J Bai; Y Lee

    2011-12-31

    We report here for the first time that fully and partially NH{sub 4}-exchanged natrolites can be prepared in hydrated states using the solution exchange method with potassium-natrolite. The structural models of the as-prepared hydrated phases and their dehydrated forms at elevated temperature were refined in space group Fdd2 using in situ synchrotron X-ray powder diffraction data and Rietveld methods. The unit-cell volumes of the hydrated NH{sub 4}-exchanged natrolites at ambient conditions, (NH{sub 4}){sub 16(2)}Al{sub 16}Si{sub 24}O{sub 80}{center_dot}14.1(9)H{sub 2}O and (NH{sub 4}){sub 5.1(1)}K{sub 10.9(1)}Al{sub 16}Si{sub 24}O{sub 80}{center_dot}15.7(3)H{sub 2}O, are found to be larger than that the original sodium-natrolite by ca. 15.6% and 12.8%, respectively. Upon temperature increase, the fully NH{sub 4}-exchanged natrolite undergoes dehydration at ca. 150 C with ca. 16.4% contraction in the unit-cell volume. The dehydrated phase of the fully NH{sub 4}-exchanged natrolite exhibits marginal volume expansion up to 425 C and then becomes amorphized during temperature decrease and exposure to atmospheric condition. In the case of the partially NH{sub 4}-exchanged natrolite, the dehydration starts from ca. 175 C with {approx}15.1% volume contraction and leads to a partial phase separation to show a phase related to the dehydrated K-natrolite. The degree of the phase separation decreases with temperature increase up to 475 C, concomitant to the gradual volume contraction occurring in the partially NH{sub 4}-exchanged natrolite in the dehydrared state. Upon temperature decrease and exposure to atmospheric condition, only the dehydrated K-natrolite is recovered as a crystalline phase from the partially NH{sub 4}-exchanged natrolite. In the hydrated model of the fully NH{sub 4}-exchanged natrolite, the ammonium cations and water molecules are statistically distributed along the elliptical channels, similar to the disordered pattern observed in natrolites exchanged

  2. Ambient Air Temperature Does Not Predict whether Small or Large Workers Forage in Bumble Bees (Bombus impatiens

    Directory of Open Access Journals (Sweden)

    Margaret J. Couvillon

    2010-01-01

    Full Text Available Bumble bees are important pollinators of crops and other plants. However, many aspects of their basic biology remain relatively unexplored. For example, one important and unusual natural history feature in bumble bees is the massive size variation seen between workers of the same nest. This size polymorphism may be an adaptation for division of labor, colony economics, or be nonadaptive. It was also suggested that perhaps this variation allows for niche specialization in workers foraging at different temperatures: larger bees might be better suited to forage at cooler temperatures and smaller bees might be better suited to forage at warmer temperatures. This we tested here using a large, enclosed growth chamber, where we were able to regulate the ambient temperature. We found no significant effect of ambient or nest temperature on the average size of bees flying to and foraging from a suspended feeder. Instead, bees of all sizes successfully flew and foraged between 16∘C and 36∘C. Thus, large bees foraged even at very hot temperatures, which we thought might cause overheating. Size variation therefore could not be explained in terms of niche specialization for foragers at different temperatures.

  3. Alcohol synthesis in a high-temperature slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, G.W.; Marquez, M.A.; McCutchen, M.S. [North Carolina State Univ., Raleigh, NC (United States)

    1995-12-31

    The overall objective of this contract is to develop improved process and catalyst technology for producing higher alcohols from synthesis gas or its derivatives. Recent research has been focused on developing a slurry reactor that can operate at temperatures up to about 400{degrees}C and on evaluating the so-called {open_quotes}high pressure{close_quotes} methanol synthesis catalyst using this reactor. A laboratory stirred autoclave reactor has been developed that is capable of operating at temperatures up to 400{degrees}C and pressures of at least 170 atm. The overhead system on the reactor is designed so that the temperature of the gas leaving the system can be closely controlled. An external liquid-level detector is installed on the gas/liquid separator and a pump is used to return condensed slurry liquid from the separator to the reactor. In order to ensure that gas/liquid mass transfer does not influence the observed reaction rate, it was necessary to feed the synthesis gas below the level of the agitator. The performance of a commercial {open_quotes}high pressure {close_quotes} methanol synthesis catalyst, the so-called {open_quotes}zinc chromite{close_quotes} catalyst, has been characterized over a range of temperature from 275 to 400{degrees}C, a range of pressure from 70 to 170 atm., a range of H{sub 2}/CO ratios from 0.5 to 2.0 and a range of space velocities from 2500 to 10,000 sL/kg.(catalyst),hr. Towards the lower end of the temperature range, methanol was the only significant product.

  4. Energy from Biomass - Comparision of biogas production at ambient temperature and at mesophilic temperature in semicontenous anaerobic digester using vegetable market waste

    Directory of Open Access Journals (Sweden)

    Dhanalakshmi Sridevi V.

    2014-03-01

    Full Text Available Studies are conducted in semicontinuous anaerobic reactors of 2 L Capacity with effective volume of 1.5 L. Experiments were carried out in the mesophilic temperature range maintained at 35°C in a thermostat, and parallel experiments were performed at ambient temperature on biogas production from the month of Februray to August. The reactors were operated with an organic loading rate of 0.5 gVS/L/d with 25 days HRT. The feed stock used for the study was vegetable market waste obtained from Koyambedu vegetable market. The specific biogas production was found to be 0.530 L gVS add-1 for the reactor operated at mesophilic temperature and in the range of 0.431 to 0.732 L gVSadd -1 for the reactor operated in the ambient temperature condition from the month of February to August. The daily biogas production was found to be similar (approximately 350 mL/d when reactors were operated at mesophilic and ambient temperature except for the period of May and June wherein higher amount of daily biogas production (472 and 529 mL/d was observed in the reactor operated at ambient temperature. The ratio of total VFA and alkalinity and propionic acid to acetic acid (PA/AA was found to be in the range of 0.25 – 0.4 and 0.34 - 1.38 during the operation of the reactor for the entire period, which was within the range reported for digester stability.

  5. The influence of internal and skin temperatures on active cutaneous vasodilation under different levels of exercise and ambient temperatures in humans

    Science.gov (United States)

    Demachi, Koichi; Yoshida, Tetsuya; Kume, Masashi; Tsuji, Michio; Tsuneoka, Hideyuki

    2013-07-01

    To clarify the influence of internal and skin temperature on the active cutaneous vasodilation during exercise, the body temperature thresholds for the onset of active vasodilation during light or moderate exercise under different ambient temperature conditions were compared. Seven male subjects performed 30 min of a cycling exercise at 20 % or 50 % of peak oxygen uptake in a room maintained at 20, 24, or 28 °C. Esophageal (Tes) and mean skin temperature (Tsk) as measured by a thermocouple, deep thigh temperature (Tdt) by the zero-heat-flow (ZHF) method, and forearm skin blood flow by laser-Doppler flowmetry (LDF) were monitored. The mean arterial pressure (MAP) was also monitored non-invasively, and the cutaneous vascular conductance (CVC) was calculated as the LDF/MAP. Throughout the experiment, the Tsk at ambient temperatures of 20, 24, and 28 °C were approximately 30, 32, and 34 °C, respectively, for both 20 % and 50 % exercise. During 50 % exercise, the Tes or Tdt thresholds for the onset of the increase in CVC were observed to be similar among the 20, 24, and 28 °C ambient conditions. During 20 % exercise, the increase in Tes and Tdt was significantly lower than those found at 50 %, and the onset of the increase in CVC was only observed at 28 °C. These results suggest that the onset of active vasodilation was affected more strongly by the internal or exercising tissue temperatures than by the skin temperatures during exercise performed at a moderate load in comparison to a light load under Tsk variations ranging from 30 °C to 34 °C. Therefore, the modification by skin temperature of the central control on cutaneous vasomotor tone during exercise may differ between different exercise loads.

  6. Effect of ambient temperature on nutrient digestibility and nitrogen balance in sheep fed brown-midrib maize silage.

    Science.gov (United States)

    Gorniak, Tobias; Meyer, Ulrich; Südekum, Karl-Heinz; Dänicke, Sven

    2014-01-01

    The aim of the experiment was to determine the impact of heat stress on nutrient digestibility and nitrogen balance in sheep fed silages differing in fibre quality. The digestibility trial was conducted at three different ambient temperatures (15°C, 25°C and 35°C for 24 h/d). The tested brown-midrib maize (Bm) silage had a higher nutrient digestibility, except for ether extract (EE) and a higher metabolisable energy (ME) content than the control maize (Con) silage. Nitrogen (N) excretion with faeces was higher but N excretion with urine was lower for sheep fed Bm silage, subsequently N balance did not differ between the two silages. Temperature had no effect on nutrient digestibility, except for crude protein (CP), but N excretion with urine was lower at elevated temperatures. A diet by temperature interaction was found for dry matter (DM) and organic matter (OM) digestibility. When the ambient temperature increased from 15°C to 25°C, the DM and OM digestibility increased in animals fed Con silage, but decreased in animals fed Bm silage. Concomitantly, ME estimated from digestible nutrients was higher for Bm than for Con at 15°C, but no differences were found at 25°C and 35°C. Effects of diet by temperature interaction, furthermore, were observed for EE and CP digestibility. Therefore, forage quality has to be considered when feeding heat-stressed animals.

  7. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes

    DEFF Research Database (Denmark)

    Chen, Xiaoying; Song, Fengbin; Liu, Fulai;

    2014-01-01

    The effect of four different arbuscular mycorrhizal fungi (AMF) on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled...... with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM...... colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde...

  8. Sow and litter response to supplemental dietary fat in lactation diets during high ambient temperatures.

    Science.gov (United States)

    Rosero, D S; van Heugten, E; Odle, J; Cabrera, R; Arellano, C; Boyd, R D

    2012-02-01

    The objective of this experiment was to determine the impact of supplemental dietary fat on total lactation energy intake and sow and litter performance during high ambient temperatures (27 ± 3°C). Data were collected from 337 mixed-parity sows from July to September in a 2,600-sow commercial unit in Oklahoma. Diets were corn-soybean meal-based with 7.5% corn distillers dried grains with solubles and 6.0% wheat middlings and contained 3.24 g of standardized ileal digestible Lys/Mcal of ME. Animal-vegetable fat blend (A-V) was supplemented at 0, 2, 4, or 6%. Sows were balanced by parity, with 113, 109, and 115 sows representing parity 1, 2, and 3 to 7 (P3+), respectively. Feed disappearance (subset of 190 sows; 4.08, 4.18, 4.44, and 4.34 kg/d, for 0, 2, 4, and 6%, respectively; P feed (sow and litter BW gain relative to feed intake) was not affected (P = 0.56), but gain:Mcal ME declined linearly with the addition of A-V (0.16, 0.15, 0.15, and 0.14 for 0, 2, 4, and 6%, respectively; P sows (3.95 kg/d) had less (P feed disappearance than P2 (4.48 kg/d) and P3+ (4.34 kg/d) sows. Body weight change in P1 sows was greater (P sows (-0.32 vs. -0.07 and 0.12 kg/d), whereas backfat loss was less (P sows compared with P1 and P2 sows. Dietary A-V improved litter ADG (P sows. Sows bred within 8 d after weaning (58.3, 72.0, 70.2, and 74.7% for 0, 2, 4, and 6%, respectively); conception rate (78.5, 89.5, 89.2, and 85.7%) and farrowing rate (71.4, 81.4, 85.5, and 78.6%) were improved (P sows were greater (P sows had lower (P sows, and respiration rate was reduced (P sows compared with P2 and P3+ sows. In conclusion, A-V improved feed disappearance and caloric intake, resulting in improved litter weight gain and subsequent reproductive performance of sows; however, feed and caloric efficiency were negatively affected.

  9. Synthesis of nanocrystalline rutile-phase titania at low temperatures

    OpenAIRE

    SANTOS, Jorge Gomes dos; Ogasawara,Tsuneharu; CORRÊA, Ronaldo Antonio

    2009-01-01

    Anatase and rutile are the predominant phases in titanium dioxide. In many cases, rutile stable phase is the desired product material, but at low temperatures methods of synthesis (aqueous route) produce metastable anatase as a major product that reverts to rutile only when heated up to 1000 °C. Calcination for obtaining rutile phase is the greatest energy demanding step for titanium dioxide production by the sulphate process, and is responsible for almost 60% of total energy consumption. In ...

  10. Testing an e2v CCD230-42 sensor for dark current performance at ambient temperatures - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Dungee, Ryan [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-20

    The design of the Guidance Focus and Alignment (GFA) system for the Dark Energy Spectroscopic Instrument (DESI) project calls for a set of charge-coupled devices (CCDs) which operate at ambient temperature. Here we assess the performance of these CCDs under such conditions. Data was collected from –21°C to 28°C and used to determine the effect of temperature on the effectiveness of dark current subtraction. Comparing the dark current uncertainty to our expected signal has shown that the DESI design specifications will be met without need for significant changes.

  11. Ambient temperature effects on photo induced gonadal cycles and hormonal secretion patterns in Great Tits from three different breeding latitudes.

    Science.gov (United States)

    Silverin, Bengt; Wingfield, John; Stokkan, Karl-Arne; Massa, Renato; Järvinen, Antero; Andersson, Nils-Ake; Lambrechts, Marcel; Sorace, Alberto; Blomqvist, Donald

    2008-06-01

    The present study determines how populations of Great Tits (Parus major) breeding in southern, mid and northern European latitudes have adjusted their reproductive endocrinology to differences in the ambient temperature during the gonadal cycle. A study based on long-term breeding data, using the Colwell predictability model, showed that the start of the breeding season has a high predictability ( approximately 0.8-0.9) at all latitudes, and that the environmental information factor (I(e)) progressively decreased from mid Italy (I(e)>4) to northern Finland (I(e)Tits from northern Norway, southern Sweden and northern Italy to sub-maximal photo-stimulatory day lengths (13L:11D) under two different ambient temperature regimes (+4 degrees C and +20 degrees C). Changes in testicular size, plasma levels of LH and testosterone were measured. The main results were: (1) Initial testicular growth rate, as well as LH secretion, was affected by temperature in the Italian, but not in birds from the two Scandinavian populations. (2) Maximum testicular size, maximum LH and testosterone levels were maintained for a progressively shorter period of time with increasing latitude, regardless of whether the birds were kept on a low or a high ambient temperature. (3) In birds from all latitudes, the development of photorefractoriness, as indicated by testicular regression and a decrease in plasma levels of LH and testosterone, started much earlier (with the exception for LH Great Tits from northern Scandinavia) when kept on +20 degrees C than when kept on +4 degrees C. The prolonging effects of a low temperature was more pronounced in Mediterranean birds, than in birds from Scandinavia, and more pronounced in Great Tits from southern Scandinavia than in Great Tits from northern Scandinavia. Ecological implications of the results are discussed, as well as possible impact of global warming on the breeding success of European Great Tits from different breeding latitudes.

  12. The embryonic life history of the tropical sea hare Stylocheilus striatus (Gastropoda: Opisthobranchia) under ambient and elevated ocean temperatures.

    Science.gov (United States)

    Horwitz, Rael; Jackson, Matthew D; Mills, Suzanne C

    2017-01-01

    Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2) emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia), a common species found throughout the Indo-West Pacific and Atlantic Oceans. Its ecological importance is well-established, particularly as a specialist grazer of the toxic cyanobacterium, Lyngbya majuscula. Although many aspects of its biology and ecology are well-known, description of its early developmental stages is lacking. First, a detailed account of this species' life history is described, including reproductive behavior, egg mass characteristics and embryonic development phases. Key developmental features are then compared between embryos developed in present-day (ambient) and predicted end-of-century elevated ocean temperatures (+3 °C). Results showed developmental stages of embryos reared at ambient temperature were typical of other opisthobranch species, with hatching of planktotrophic veligers occurring 4.5 days post-oviposition. However, development times significantly decreased under elevated temperature, with key embryonic features such as the velum, statocysts, operculum, eyespots and protoconch developing approximately 24 h earlier when compared to ambient temperature. Although veligers hatched one day earlier under elevated temperature, their shell size decreased by approximately 20%. Our findings highlight how an elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality.

  13. The embryonic life history of the tropical sea hare Stylocheilus striatus (Gastropoda: Opisthobranchia) under ambient and elevated ocean temperatures

    Science.gov (United States)

    Jackson, Matthew D.; Mills, Suzanne C.

    2017-01-01

    Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2) emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia), a common species found throughout the Indo-West Pacific and Atlantic Oceans. Its ecological importance is well-established, particularly as a specialist grazer of the toxic cyanobacterium, Lyngbya majuscula. Although many aspects of its biology and ecology are well-known, description of its early developmental stages is lacking. First, a detailed account of this species’ life history is described, including reproductive behavior, egg mass characteristics and embryonic development phases. Key developmental features are then compared between embryos developed in present-day (ambient) and predicted end-of-century elevated ocean temperatures (+3 °C). Results showed developmental stages of embryos reared at ambient temperature were typical of other opisthobranch species, with hatching of planktotrophic veligers occurring 4.5 days post-oviposition. However, development times significantly decreased under elevated temperature, with key embryonic features such as the velum, statocysts, operculum, eyespots and protoconch developing approximately 24 h earlier when compared to ambient temperature. Although veligers hatched one day earlier under elevated temperature, their shell size decreased by approximately 20%. Our findings highlight how an elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality. PMID:28168118

  14. The embryonic life history of the tropical sea hare Stylocheilus striatus (Gastropoda: Opisthobranchia under ambient and elevated ocean temperatures

    Directory of Open Access Journals (Sweden)

    Rael Horwitz

    2017-02-01

    Full Text Available Ocean warming represents a major threat to marine biota worldwide, and forecasting ecological ramifications is a high priority as atmospheric carbon dioxide (CO2 emissions continue to rise. Fitness of marine species relies critically on early developmental and reproductive stages, but their sensitivity to environmental stressors may be a bottleneck in future warming oceans. The present study focuses on the tropical sea hare, Stylocheilus striatus (Gastropoda: Opisthobranchia, a common species found throughout the Indo-West Pacific and Atlantic Oceans. Its ecological importance is well-established, particularly as a specialist grazer of the toxic cyanobacterium, Lyngbya majuscula. Although many aspects of its biology and ecology are well-known, description of its early developmental stages is lacking. First, a detailed account of this species’ life history is described, including reproductive behavior, egg mass characteristics and embryonic development phases. Key developmental features are then compared between embryos developed in present-day (ambient and predicted end-of-century elevated ocean temperatures (+3 °C. Results showed developmental stages of embryos reared at ambient temperature were typical of other opisthobranch species, with hatching of planktotrophic veligers occurring 4.5 days post-oviposition. However, development times significantly decreased under elevated temperature, with key embryonic features such as the velum, statocysts, operculum, eyespots and protoconch developing approximately 24 h earlier when compared to ambient temperature. Although veligers hatched one day earlier under elevated temperature, their shell size decreased by approximately 20%. Our findings highlight how an elevated thermal environment accelerates planktotrophic development of this important benthic invertebrate, possibly at the cost of reducing fitness and increasing mortality.

  15. Biodegradation of Synthetic Polyesters (BTA and PCL with Natural Flora in Soil Burial and Pure Cultures under Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Mona K. Gouda

    2012-03-01

    Full Text Available The aim of this study was to study the biodegradation of two synthetic polyesters, one aliphaticaromatic (1, 4-butanediol, terephthalic-adipic acid, BTA and the other aliphatic (poly (,-caprolactone, PCL, under different soil types (canal shore soil, garden soil, compost and Peat moss, respectively, as well as using locally isolated cultures at ambient temperature. The results showed that the BTA films buried in canal shore and garden soil were degraded faster than that in the other soils. After six weeks about 90, 88 and 80% were degraded in garden, canal shore soil and compost respectively, while only 52% were degraded in Peat moss. On the other hand, 95 and 93% weight loss was obtained for PCL films buried for three weeks in canal shore and garden soil respectively. The Scanning Electron Microscope photos confirm the results of weight loss and revealed the presence of cracks and fungal growth on films buried in different soils. The results with pure cultures, especially with Fusarium solani, also confirmed the biodegradability of two polyesters under ambient temperature. Finally, it could be concluded that both synthetic polyester are degradable under ambient conditions.

  16. Splashing phenomena of room temperature liquid metal droplet striking on the pool of the same liquid under ambient air environment

    CERN Document Server

    Li, Haiyan; Wang, Lei; Gao, Yunxia; Liu, Jing

    2013-01-01

    In this article, the fluid dynamics of room temperature liquid metal (RTLM) droplet impacting onto a pool of the same liquid in ambient air was investigated. A series of experiments were conducted in order to disclose the influence of the oxidation effect on the impact dynamics. The droplet shape and impact phenomenology were recorded with the aid of a high-speed digital camera. The impact energy stored in the splash structures was estimated via a theoretical model and several morphological parameters obtained from instantaneous images of the splash. It was observed that the droplet shape and the splashing morphology of RTLM were drastically different from those of water, so was the impact dynamics between room temperature LM pool and high temperature LM pool. The energy analysis disclosed that the height of the jet is highly sensitive to the viscosity of the fluid, which is subjected to the oxidation effect and temperature effect simultaneously, and thus perfectly explained the phenomena. These basic finding...

  17. Thermal degradation of concrete in the temperature range from ambient to 315{degrees}C (600{degrees}F)

    Energy Technology Data Exchange (ETDEWEB)

    Kassir, M.K.; Bandyopadhyay, K.K.; Reich, M.

    1993-06-01

    This report is concerned with determining the effect of elevated temperatures on the behavior of concrete. Emphasis is placed on quantifying the degree of potential degradation of the physical properties of concrete in high-level waste storage tanks. The range in the temperature elevation of interest covers from ambient to 315{degrees}C (600{degrees}F). The literature has been reviewed to examine the applicable experimental data and quantify the degradation in the concrete and reinforcing steel. Since many variables and test conditions control the results in the data base, upper and lower bounds of the degraded properties at temperatures applicable to the environments of the storage tanks are summarized and presented in explicit forms. Such results are useful in assessing the effect of elevated temperatures on the structural behavior of the tanks. Also, they provide the technical basis for a parametric study that may be necessary to investigate the thermal aspects of the structural integrity of the tanks.

  18. Responses of wheat and rice to factorial combinations of ambient and elevated CO2 and temperature in FACE experiments.

    Science.gov (United States)

    Cai, Chuang; Yin, Xinyou; He, Shuaiqi; Jiang, Wenyu; Si, Chuanfei; Struik, Paul C; Luo, Weihong; Li, Gang; Xie, Yingtian; Xiong, Yan; Pan, Genxing

    2016-02-01

    Elevated CO2 and temperature strongly affect crop production, but understanding of the crop response to combined CO2 and temperature increases under field conditions is still limited while data are scarce. We grew wheat (Triticum aestivum L.) and rice (Oryza sativa L.) under two levels of CO2 (ambient and enriched up to 500 μmol mol(-1) ) and two levels of canopy temperature (ambient and increased by 1.5-2.0 °C) in free-air CO2 enrichment (FACE) systems and carried out a detailed growth and yield component analysis during two growing seasons for both crops. An increase in CO2 resulted in higher grain yield, whereas an increase in temperature reduced grain yield, in both crops. An increase in CO2 was unable to compensate for the negative impact of an increase in temperature on biomass and yield of wheat and rice. Yields of wheat and rice were decreased by 10-12% and 17-35%, respectively, under the combination of elevated CO2 and temperature. The number of filled grains per unit area was the most important yield component accounting for the effects of elevated CO2 and temperature in wheat and rice. Our data showed complex treatment effects on the interplay between preheading duration, nitrogen uptake, tillering, leaf area index, and radiation-use efficiency, and thus on yield components and yield. Nitrogen uptake before heading was crucial in minimizing yield loss due to climate change in both crops. For rice, however, a breeding strategy to increase grain number per m(2) and % filled grains (or to reduce spikelet sterility) at high temperature is also required to prevent yield reduction under conditions of global change.

  19. Temperature Dependence on The Synthesis of Jatropha Biolubricant

    Energy Technology Data Exchange (ETDEWEB)

    Resul, Muhammad Faiz M Gunam; Ghazi, Tinia Idaty Mohd; Idris, Azni, E-mail: tinia@eng.upm.edu.my [Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2011-02-15

    Jatropha oil has good potential as the renewable energy as well as lubricant feedstock. The synthesis of jatropha biolubricant was performed by transesterification of jatropha methyl ester (JME) with trimethyl-ol-propane (TMP) with sodium methoxide (NaOCH3) catalyst. The effects of temperature on the synthesis were studied at a range between 120 deg. C and 200 deg. C with pressure kept at 10mbar. The conversion of JME to jatropha biolubricant was found to be the highest (47%) at 200 deg. C. However, it was suggested that the optimum temperature of the reaction is at 150 deg. C due to insignificant improvement in biolubricant production. To maintain forward reaction, the excess amount of JME was maintained at 3.9:1 ratios to TMP. Kinetic study was done and compared. The synthesis was found to follow a second order reaction with overall rate constant of 1.49 x 10-1 (%wt/wt.min.deg. C)-1. The estimated activation energy was 3.94 kJ/mol. Pour point for jatropha biolubricant was at -3 deg. C and Viscosity Index (VI) ranged from 178 to 183. The basic properties of jatropha biolubricant, pour point and viscosities are found comparable to other plant based biolubricant, namely palm oil and soybean based biolubricant.

  20. Temperature Dependence on The Synthesis of Jatropha Biolubricant

    Science.gov (United States)

    Gunam Resul, Muhammad Faiz M.; Idaty Mohd Ghazi, Tinia; Idris, Azni

    2011-02-01

    Jatropha oil has good potential as the renewable energy as well as lubricant feedstock. The synthesis of jatropha biolubricant was performed by transesterification of jatropha methyl ester (JME) with trimethyl-ol-propane (TMP) with sodium methoxide (NaOCH3) catalyst. The effects of temperature on the synthesis were studied at a range between 120°C and 200°C with pressure kept at 10mbar. The conversion of JME to jatropha biolubricant was found to be the highest (47%) at 200°C. However, it was suggested that the optimum temperature of the reaction is at 150°C due to insignificant improvement in biolubricant production. To maintain forward reaction, the excess amount of JME was maintained at 3.9:1 ratios to TMP. Kinetic study was done and compared. The synthesis was found to follow a second order reaction with overall rate constant of 1.49 × 10-1 (%wt/wt.min.°C)-1. The estimated activation energy was 3.94 kJ/mol. Pour point for jatropha biolubricant was at -3°C and Viscosity Index (VI) ranged from 178 to 183. The basic properties of jatropha biolubricant, pour point and viscosities are found comparable to other plant based biolubricant, namely palm oil and soybean based biolubricant.

  1. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes.

    Science.gov (United States)

    Chen, Xiaoying; Song, Fengbin; Liu, Fulai; Tian, Chunjie; Liu, Shengqun; Xu, Hongwen; Zhu, Xiancan

    2014-01-01

    The effect of four different arbuscular mycorrhizal fungi (AMF) on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT) and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

  2. Effect of Different Arbuscular Mycorrhizal Fungi on Growth and Physiology of Maize at Ambient and Low Temperature Regimes

    Directory of Open Access Journals (Sweden)

    Xiaoying Chen

    2014-01-01

    Full Text Available The effect of four different arbuscular mycorrhizal fungi (AMF on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

  3. Ambient temperature enhanced acute cardiovascular-respiratory mortality effects of PM2.5 in Beijing, China

    Science.gov (United States)

    Li, Yi; Ma, Zhiqiang; Zheng, Canjun; Shang, Yu

    2015-12-01

    Studies have shown that temperature could modify the effect of ambient fine particles on mortality risk. In assessing air pollution effects, temperature is usually considered as a confounder. However, ambient temperature can alter people's physiological response to air pollution and might "modify" the impact of air pollution on health outcomes. This study investigated the interaction between daily PM2.5 and daily mean temperature in Beijing, China, using data for the period 2005-2009. Bivariate PM2.5-temperature response surfaces and temperature-stratified generalized additive model (GAM) were applied to study the effect of PM2.5 on cardiovascular, respiratory mortality, and total non-accidental mortality across different temperature levels. We found that low temperature could significantly enhance the effect of PM2.5 on cardiovascular mortality. For an increase of 10 μg/m3 in PM2.5 concentration in the lowest temperature range (-9.7˜2.6 °C), the relative risk (RR) of cardiovascular mortality increased 1.27 % (95 % CI 0.38˜2.17 %), which was higher than that of the whole temperature range (0.59 %, 95 % CI 0.22-1.16 %). The largest effect of PM2.5 on respiratory mortality appeared in the high temperature range. For an increase of 10 μg/m3 in PM2.5 concentration, RR of respiratory mortality increased 1.70 % (95 % CI 0.92˜3.33 %) in the highest level (23.50˜31.80 °C). For the total non-accidental mortality, significant associations appeared only in low temperature levels (-9.7˜2.6 °C): for an increase of 10 μg/m3 in current day PM2.5 concentration, RR increased 1.27 % (95 % CI 0.46˜2.00 %) in the lowest temperature level. No lag effect was observed. The results suggest that in air pollution mortality time series studies, the possibility of an interaction between air pollution and temperature should be considered.

  4. High temperature auto-propagating synthesis of advanced ceramic materials

    Energy Technology Data Exchange (ETDEWEB)

    Cao, G.; Morbidelli, M. (Cagliari Univ. (Italy). Dip. di Ingegneria Chimica e Materiali)

    1993-01-01

    This paper analyzes the modelling and experimental aspects relative to the production of advanced ceramic materials (i.e., carbides, borides and silicides of suitable transition metals) by means of high temperature auto-propagating synthesis. This process is characterized by a reaction front which, once triggered, auto-propagates itself through the reagent mix in the form of a combustion wave, taking advantage of the strong exothermic nature of the reaction itself. The analysis in this paper includes an investigation of the capability of models to accurately simulate the synthesis process. The validity of one particular model is checked by comparison with experimental results reported in literature. In addition, non-linear parametric sensitivity analysis is used to define 'a priori' suitable operating conditions which would guarantee ignition of the reagent mix and contemporaneously allow the optimization of process energy consumption.

  5. Effect of Temperature and Catalyst Concentration on Polyglycerol during Synthesis

    Directory of Open Access Journals (Sweden)

    Carolina Ardila-Suárez

    2015-01-01

    Full Text Available Morphology, molecular weight, polydispersity, functionality, and thermal properties are important characteristics when using polyglycerol as a building block in the development of materials for industrial applications such as hydrogels, surfactants, asphalts additives, cosmetics, pharmaceutical, biomedical, and drug delivery systems. In this study several experimental techniques are used to understand the effect of process variables during synthesis in the catalyzed etherification of glycerol, a coproduct of biodiesel industry. Biobased polyglycerol is a high-valued product, which is useful as building block material because of its remarkable features, for instance, multiple hydrophilic groups, excellent biocompatibility, and highly flexible aliphatic polyether backbone. A connection between polyglycerol characteristics and process variables during synthesis allows the control of glycerol polymerization through reaction conditions. We show that temperature and catalyst concentration can be tuned with the aim of tailoring fundamental polyglycerol parameters including molecular weight, polydispersity, morphology, and functionality.

  6. The potential effect of differential ambient and deployment chamber temperatures on PRC derived sampling rates with polyurethane foam (PUF) passive air samplers

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, Karen, E-mail: k.kennedy@uq.edu.a [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia); Hawker, Darryl W. [Griffith University, School of Environment, Nathan QLD 4111 (Australia); Bartkow, Michael E. [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia); Carter, Steve [Queensland Health Forensic and Scientific Services, Coopers Plains QLD 4108 (Australia); Ishikawa, Yukari; Mueller, Jochen F. [University of Queensland, EnTox (National Research Centre for Environmental Toxicology), 39 Kessels Rd., Coopers Plains QLD 4108 (Australia)

    2010-01-15

    Performance reference compound (PRC) derived sampling rates were determined for polyurethane foam (PUF) passive air samplers in both sub-tropical and temperate locations across Australia. These estimates were on average a factor of 2.7 times higher in summer than winter. The known effects of wind speed and temperature on mass transfer coefficients could not account for this observation. Sampling rates are often derived using ambient temperatures, not the actual temperatures within deployment chambers. If deployment chamber temperatures are in fact higher than ambient temperatures, estimated sampler-air partition coefficients would be greater than actual partition coefficients resulting in an overestimation of PRC derived sampling rates. Sampling rates determined under measured ambient temperatures and estimated deployment chamber temperatures in summer ranged from 7.1 to 10 m{sup 3} day{sup -1} and 2.2-6.8 m{sup 3} day{sup -1} respectively. These results suggest that potential differences between ambient and deployment chamber temperatures should be considered when deriving PRC-based sampling rates. - Internal deployment chamber temperatures rather than ambient temperatures may be required to accurately estimate PRC-based sampling rates.

  7. Anionic liposome template synthesis of raspberry-like hollow silica particle under ambient conditions with basic catalyst.

    Science.gov (United States)

    Ishii, Haruyuki; Sato, Kumi; Nagao, Daisuke; Konno, Mikio

    2012-04-01

    Hollow silica particle was obtained with a vesicle template synthesis in water under ambient conditions in the presence of ammonia. Biomimetic vesicles, liposomes were used, which consisted of a zwitterionic phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and a tiny amount of charged amphiphiles, hexadecylamine (HDA) or dicetylphosphate (DCP). Aggregation of silica occurred for DPPC or cationic DPPC/HDA liposome, whereas well-dispersed hollow silica particle could be obtained for anionic DPPC/DCP liposome. The hollow particle synthesized with the anionic liposome had single-layered and raspberry-like structures. Electrostatic repulsion between anionic vesicles maintained stable dispersion of the as-synthesized particles during the reaction. Formation of the raspberry-like morphology is explained by silica particle precipitation selectively induced around the liposomes under basic conditions due to affinity of silica precursors for the liposomes. Synthesis of well-dispersed hollow silica particle with a raspberry-like morphology is the first report in vesicle template syntheses.

  8. A complementary role for ELF3 and TFL1 in the regulation of flowering time by ambient temperature.

    Science.gov (United States)

    Strasser, Bárbara; Alvarez, Mariano J; Califano, Andrea; Cerdán, Pablo D

    2009-05-01

    Plants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Sub-optimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one requiring TFL1 and another requiring ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants, which have a constitutive photoperiodic response. In contrast to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. Gene expression profiles revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes, and identified CCA1 and SOC1/AGL20 as being important cross-talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling.

  9. Time series analysis of the association between ambient temperature and cerebrovascular morbidity in the elderly in Shanghai, China

    Science.gov (United States)

    Zhang, Xian-Jing; Ma, Wei-Ping; Zhao, Nai-Qing; Wang, Xi-Ling

    2016-01-01

    Research on the association between ambient temperature and cerebrovascular morbidity is scarce in China. In this study, we applied mixed generalized additive model (MGAM) to daily counts of cerebrovascular disease of Shanghai residents aged 65 years or older from 2007–2011, stratified by gender. Weighted daily mean temperature up to lags of one week was smoothed by natural cubic spline, and was added into the model to assess both linear and nonlinear effects of temperature. We found that when the mean temperature increased by 1 °C, the male cases of cerebrovascular disease reduced by 0.95% (95% Confidence Interval (CI): 0.80%, 1.10%) or reduced by 0.34% (95% CI: ‑0.68, 1.36%) in conditions of temperature was below or above 27 °C. However, for every 1 °C increase in temperature, the female cases of cerebrovascular disease increased by 0.34% (95% CI: ‑0.26%, 0.94%) or decreased by 0.92% (95% CI: 0.72, 1.11%) in conditions of temperature was below or above 8 °C, respectively. Temperature and cerebrovascular morbidity is negatively associated in Shanghai. MGAM is recommended in assessing the association between environmental hazards and health outcomes in time series studies.

  10. Alternative Refrigerant Evaluation for High-Ambient-Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Goetzler, William [Navigant Consulting Inc., Burlington, MA (United States); Guernsey, Matt [Navigant Consulting Inc., Burlington, MA (United States); Kassuga, Theo [Navigant Consulting Inc., Burlington, MA (United States)

    2015-10-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient-Temperature Evaluation Program for low– global warming potential (Low-GWP) Refrigerants aims to develop an understanding of the performance of low-GWP alternative refrigerants to hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high-ambient-temperature conditions. This final report describes the parties involved, the alternative refrigerant selection process, the test procedures, and the final results.

  11. Alternative Refrigerant Evaluation for High-Ambient Temperature Environments: R-22 and R-410A Alternatives for Mini-Split Air Conditioners

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [ORNL; Munk, Jeffrey D [ORNL; Shrestha, Som S [ORNL; Linkous, Randall Lee [ORNL; Goetzler, William [Navigant Consulting Inc.; Guernsey, Matt [Navigant Consulting Inc.; Kassuga, Theo [Navigant Consulting Inc.

    2015-08-01

    The Oak Ridge National Laboratory (ORNL) High-Ambient Temperature Testing Program for Low-GWP Refrigerants aims to develop an understanding of the performance of low-Global Warming Potential (low-GWP) alternatives to Hydrochlorofluorocarbon (HCFC) and Hydrofluorocarbon (HFC) refrigerants in mini-split air conditioners under high ambient temperature conditions. This interim working paper describes the parties involved, the alternative refrigerants selection process, the test procedures, and the preliminary results.

  12. Tailpipe emissions from gasoline direct injection (GDI) and port fuel injection (PFI) vehicles at both low and high ambient temperatures.

    Science.gov (United States)

    Zhu, Rencheng; Hu, Jingnan; Bao, Xiaofeng; He, Liqiang; Lai, Yitu; Zu, Lei; Li, Yufei; Su, Sheng

    2016-09-01

    Vehicle emissions are greatly influenced by various factors that are related to engine technology and driving conditions. Only the fuel injection method and ambient temperature are investigated in this research. Regulated gaseous and particulate matter (PM) emissions from two advanced gasoline-fueled vehicles, one with direct fuel injection (GDI) and the other with port fuel injection (PFI), are tested with conventional gasoline and ethanol-blended gasoline (E10) at both -7 °C and 30 °C. The total particle number (PN) concentrations and size distributions are monitored with an Electrical Low Pressure Impactor (ELPI(+)). The solid PN concentrations are measured with a condensation particle counter (CPC) after removing volatile matters through the particle measurement program (PMP) system. The results indicate that decreasing the ambient temperature from 30 °C to -7 °C significantly increases the fuel consumption and all measured emissions except for NOx. The GDI vehicle exhibits lower fuel consumption than the PFI vehicle but emits more total hydrocarbons (THC), PM mass and solid PN emissions at 30 °C. The adaptability of GDI technology appears to be better than that of PFI technology at low ambient temperature. For example, the CO, THC and PM mass emission factors of the PFI vehicle are higher than those of the GDI vehicle and the solid PN emission factors are comparable in the cold-start tests at -7 °C. Specifically, during start-up the particulate matter emissions of the PFI are much higher than the GDI. In most cases, the geometric mean diameter (GMD) of the accumulation mode particles is 58-86 nm for both vehicles, and the GMD of the nucleation mode particles is 10-20 nm. The results suggest that the gaseous and particulate emissions from the PFI vehicle should not be neglected compared to those from the GDI vehicle especially in a cold environment.

  13. Design, Development and Implementation of the IR Signalling Techniques for Monitoring Ambient and Body Temperature in WBANs

    Directory of Open Access Journals (Sweden)

    Attiya Baqai

    2014-07-01

    Full Text Available Healthcare systems such as hospitals, homecare, telemedicine, and physical rehabilitation are expected to be revolutionized by WBAN (Wireless Body Area Networks. This research work aims to investigate, design, optimize, and demonstrate the applications of IR (Infra-Red communication systems in WBAN. It is aimed to establish a prototype WBAN system capable of measuring Ambient and Body Temperature using LM35 as temperature sensor and transmitting and receiving the data using optical signals. The corresponding technical challenges that have to be faced are also discussed in this paper. Investigations are carried out to efficiently design the hardware using low-cost and low power optical transceivers. The experimental results reveal the successful transmission and reception of Ambient and Body Temperatures over short ranges i.e. up to 3-4 meters. A simple IR transceiver with an LED (Light Emitting Diodes, TV remote control IC and Arduino microcontroller is designed to perform the transmission with sufficient accuracy and ease. Experiments are also performed to avoid interference from other sources like AC and TV remote control signals by implementing IR tags

  14. A study on the behaviour of TLD-100 glow peaks at extreme ambient temperatures in Riyadh, Saudi Arabia.

    Science.gov (United States)

    Al-Haj, Abdalla N; Lagarde, Charlie S

    2006-01-01

    In this study, the temperature-induced variations in the TLD-100 response and the modifications in its glow peaks are investigated in real environmental exposure conditions in Riyadh, Saudi Arabia, where ambient temperatures during summer reach >45 degrees C and with relative humidity of 8814 TLD cardholders were deployed as environmental dosemeters for a period of approximately 1 month for 12 consecutive months. One group was irradiated to 5 mGy 137Cs prior to deployment; another was irradiated to the same dose after deployment, while the last group was left unirradiated. Analysis of glow curves was done using commercially available glow curve deconvolution software (CGCD). Monthly variations in peak 3, 4 and 5 areas relative to the corresponding peak areas of a prompt glow curve are presented. Results of this study show good TL signal compensation between peaks 4 and 5 at all ambient temperatures encountered in this experiment, despite the observed individual variations experienced by each of these peaks. The sum of peak 4 and 5 areas is constant to within approximately 10%, for both pre- and post-irradiated dosemeters, during this 12-month cycle.

  15. Design and Application of Variable Temperature Setup for Scanning Electron Microscopy in Gases and Liquids at Ambient Conditions.

    Science.gov (United States)

    Al-Asadi, Ahmed S; Zhang, Jie; Li, Jianbo; Potyrailo, Radislav A; Kolmakov, Andrei

    2015-06-01

    Scanning electron microscopy (SEM) of nanoscale objects in dry and fully hydrated conditions at different temperatures is of critical importance in revealing details of their interactions with an ambient environment. Currently available WETSEM capsules are equipped with thin electron-transparent membranes and allow imaging of samples at atmospheric pressure, but do not provide temperature control over the sample. Here, we developed and tested a thermoelectric cooling/heating setup for WETSEM capsules to allow ambient pressure in situ SEM studies with a temperature range between -15 and 100°C in gaseous, liquid, and frozen conditions. The design of the setup also allows for correlation of the SEM with optical microscopy and spectroscopy. As a demonstration of the possibilities of the developed approach, we performed real-time in situ microscopy studies of water condensation on a surface of Morpho sulkowskyi butterfly wing scales. We observed that initial water nucleation takes place on top of the scale ridges. These results confirmed earlier discovery of a preexisting polarity gradient of the ridges of Morpho butterflies. Our developed thermoelectric cooling/heating setup for environmental capsules meets the diverse needs for in situ nanocharacterization in material science, catalysis, microelectronics, chemistry, and biology.

  16. Effects of ambient and preceding temperatures and metabolic genes on flight metabolism in the Glanville fritillary butterfly.

    Science.gov (United States)

    Wong, Swee Chong; Oksanen, Alma; Mattila, Anniina L K; Lehtonen, Rainer; Niitepõld, Kristjan; Hanski, Ilkka

    2016-02-01

    Flight is essential for foraging, mate searching and dispersal in many insects, but flight metabolism in ectotherms is strongly constrained by temperature. Thermal conditions vary greatly in natural populations and may hence restrict fitness-related activities. Working on the Glanville fritillary butterfly (Melitaea cinxia), we studied the effects of temperature experienced during the first 2 days of adult life on flight metabolism, genetic associations between flight metabolic rate and variation in candidate metabolic genes, and genotype-temperature interactions. The maximal flight performance was reduced by 17% by 2 days of low ambient temperature (15 °C) prior to the flight trial, mimicking conditions that butterflies commonly encounter in nature. A SNP in phosphoglucose isomerase (Pgi) had a significant association on flight metabolic rate in males and a SNP in triosephosphate isomerase (Tpi) was significantly associated with flight metabolic rate in females. In the Pgi SNP, AC heterozygotes had higher flight metabolic rate than AA homozygotes following low preceding temperature, but the trend was reversed following high preceding temperature, consistent with previous results on genotype-temperature interaction for this SNP. We suggest that these results on 2-day old butterflies reflect thermal effect on the maturation of flight muscles. These results highlight the consequences of variation in thermal conditions on the time scale of days, and they contribute to a better understanding of the complex dynamics of flight metabolism and flight-related activities under conditions that are relevant for natural populations living under variable thermal conditions.

  17. Twinning Behavior of a Basal Textured Commercially Pure Titanium Alloy TA2 at Ambient and Cryogenic Temperatures

    Institute of Scientific and Technical Information of China (English)

    Jin-ru LUO; Xiao SONG; Lin-zhong ZHUANG; Ji-shan ZHANG

    2016-01-01

    Twinning greatly affects the microstructure and mechanical performance of titanium alloys.The twinning behavior of a basal textured commercially pure titanium TA2 plates rolled to 4% reduction at the ambient and cryo-genic temperatures has been investigated.Microstructures of the rolled samples were investigated by optical micro-scope (OM)and the twinning analysis was carried out based on orientation data collected by electron back-scatter diffraction (EBSD).{1 122}contraction twins,{1 124}contraction twins and {1012}extension twins have been ob-served.Twinning mode activity varied with rolling temperature.Twinning is considered as the dominant deformation mechanism during rolling at both temperatures for the strain condition.Larger proportion of grains activates twin-ning during cryorolling,and greater number and more diverse types of twins are observed;manifestly related to the suppression of dislocation slips at the cryogenic temperature.{1 122 }contraction twins are the dominate twin type within samples rolled at both temperatures.Several {1 124}contraction twins are observed in the cryorolled sample while there are only a few in the sample rolled at room temperature.A few tiny {1012}twins have been identified in both samples.{1 124}contraction twins are preferentially activated at cryogenic deformation temperature and the{1012}extension twins may result in local strain accommodation.

  18. Hot-wire measurements with automatic compensation of ambient temperature changes

    Directory of Open Access Journals (Sweden)

    Miheev Nikolay I.

    2015-01-01

    Full Text Available A single sensor hot-wire device with automatic temperature compensation for velocity measurements is developed. Experience in measuring the velocity and temperature in a flow with variable temperature using self-made hot-wire equipment and probes is discussed. Results of the corresponding methodical experiments are presented.

  19. Hot-wire measurements with automatic compensation of ambient temperature changes

    OpenAIRE

    Miheev Nikolay I.; Molochnikov Valeriy M.; Kratirov Dmitriy V.; Hayrnasov Konstantin R.; Zanko Philipp S.

    2015-01-01

    A single sensor hot-wire device with automatic temperature compensation for velocity measurements is developed. Experience in measuring the velocity and temperature in a flow with variable temperature using self-made hot-wire equipment and probes is discussed. Results of the corresponding methodical experiments are presented.

  20. Coolant and ambient temperature control for chillerless liquid cooled data centers

    Energy Technology Data Exchange (ETDEWEB)

    Chainer, Timothy J.; David, Milnes P.; Iyengar, Madhusudan K.; Parida, Pritish R.; Simons, Robert E.

    2016-02-02

    Cooling control methods include measuring a temperature of air provided to a plurality of nodes by an air-to-liquid heat exchanger, measuring a temperature of at least one component of the plurality of nodes and finding a maximum component temperature across all such nodes, comparing the maximum component temperature to a first and second component threshold and comparing the air temperature to a first and second air threshold, and controlling a proportion of coolant flow and a coolant flow rate to the air-to-liquid heat exchanger and the plurality of nodes based on the comparisons.

  1. Low Temperature One-Step Synthesis of Barium Titanate:Thermodynamic Modeling and Experimental Synthesis

    Institute of Scientific and Technical Information of China (English)

    沈志刚; 李世刚; 刘朝文; 张建文; 陈建峰

    2005-01-01

    A thermodynamic model has been developed to determine the reaction conditions favoring low temperature direct synthesis of barium titanate (BaTiO3). The method utilizes standard-state thermodynamic data for solid and aqueous species and a Debye-Hǔckel coefficients model to represent solution nonideality. The method has been used to generate phase stability diagrams that indicate the ranges of pH and reagent concentrations, for which various species predominate in the system at a given temperature. Also, yield diagrams have been constructed that indicate the concentration, pH and temperature conditions for which different yields of crystalline BaTiO3 can be obtained. The stability and yield diagrams have been used to predict the optimum synthesis conditions (e.g.,reagent concentrations, pH and temperature). Subsequently, these predictions have been experimentally verified.As a result, phase-pure perovskite BaTiO3 has been obtained at temperature ranging from 55 to 85℃ using BaCl2,TiCl4 as a source for Ba and Ti. and NaOH as a orecioitator.

  2. Low temperature synthesis of SiCN nanostructures

    Institute of Scientific and Technical Information of China (English)

    CHENG Wen Juan; MA XueMing

    2009-01-01

    Silicon carbon nitride (SiCN) nanowires, nanorods and nanotubes have gained much attention due to their excellent field emission and photoluminescence properties. These nanostructures were usually grown using catalysts at high temperature (800-1000℃). In this paper, synthesis of SiCN nanostruc-tures at a temperature less than 500℃ is reported. Various kinds of SiCN nanostructures were synthe-sized using microwave plasma chemical vapor deposition method. Gas mixtures of CH4, H2 and N2 were used as precursors and Si chips were inserted in the sample holder at symmetrical positions around the specimen as additional Si sources. Metallic gallium was used as the liquid medium in a mechanism similar to vapor-liquid-solid. Morphologies of the resultant were characterized by field emission scan-ning electron microscopy. Energy dispersive spectrometry and X-ray photoelectron spectroscopy were used to characterize their compositions and bonding states.

  3. Single Crystal Synthesis and STM Studies of High Temperature Superconductors

    Science.gov (United States)

    Barrientos, Alfonso

    1997-01-01

    This is a final report for the work initiated in September of 1994 under the grant NAG8-1085 - NASA/OMU, on the fabrication of bulk and single crystal synthesis, specific heat measuring and STM studies of high temperature superconductors. Efforts were made to fabricate bulk and single crystals of mercury based superconducting material. A systematic thermal analysis on the precursors for the corresponding oxides and carbonates were carried out to synthesized bulk samples. Bulk material was used as seed in an attempt to grow single crystals by a two-step self flux process. On the other hand bulk samples were characterized by x-ray diffraction, electrical resistivity and magnetic susceptibility, We studied the specific heat behavior in the range from 80 to 300 K. Some preliminary attempts were made to study the atomic morphology of our samples. As part of our efforts we built an ac susceptibility apparatus for measuring the transition temperature of our sintered samples.

  4. Low temperature synthesis of SiCN nanostructures

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Silicon carbon nitride (SiCN) nanowires, nanorods and nanotubes have gained much attention due to their excellent field emission and photoluminescence properties. These nanostructures were usually grown using catalysts at high temperature (800―1000℃). In this paper, synthesis of SiCN nanostruc-tures at a temperature less than 500℃ is reported. Various kinds of SiCN nanostructures were synthe-sized using microwave plasma chemical vapor deposition method. Gas mixtures of CH4, H2 and N2 were used as precursors and Si chips were inserted in the sample holder at symmetrical positions around the specimen as additional Si sources. Metallic gallium was used as the liquid medium in a mechanism similar to vapor-liquid-solid. Morphologies of the resultant were characterized by field emission scan-ning electron microscopy. Energy dispersive spectrometry and X-ray photoelectron spectroscopy were used to characterize their compositions and bonding states.

  5. Synthesis and microdiffraction at extreme pressures and temperatures.

    Science.gov (United States)

    Lavina, Barbara; Dera, Przemyslaw; Meng, Yue

    2013-10-07

    High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 (1) will be shown.

  6. Performance evaluation of a two-phase anaerobic digestion process of synthetic domestic wastewater at ambient temperature.

    Science.gov (United States)

    Guerrero, L; Montalvo, S; Coronado, E; Chamy, R; Poirrier, P; Crutchik, D; Sánchez, E; De La Rubia, M A; Borja, R

    2009-06-01

    A two-phase anaerobic digestion process of synthetic domestic wastewater was studied at ambient temperature in mild to cold climates. The hydrolytic stage was carried out in a continuous stirred tank reactor with an effective volume of 1.2 L. The hydrolytic reactor operated at hydraulic retention times (HRTs) in the range of 1.3 to 2.7 h, which allowed for optimum HRT to be obtained in order to achieve a maximum amount of soluble COD. For the methanogenic stage, an up-flow anaerobic filter with a volume of 1.35 L and corrugated plastic rings as biomass immobilization support were used. During the investigation, the ambient temperature ranged between 21 degrees C and 24 degrees C. Synthetic domestic wastewater with a COD of 700 mg/L was used as substrate. The study was performed at total organic loading rates (OLR(T)) of 2.0-4.3 g COD/L. d, with a global HRT (including both hydrolytic and methanogenic stages) of 2.8-5.8 hours. A maximum percentage of organic matter removed of 88% was achieved at a global HRT of 5.8 hours. Under these operating conditions, the production of biogas was 97% higher than that obtained in the one-phase anaerobic digestion process. Additionally, the kinetics involved in the hydrolytic stage was determined using the Contois kinetic model, which adequately predicted the experimental results.

  7. 绿橙常温保鲜的研究%Storage of Hainan Green Oranges at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    陈婷; 王志国; 刘四新; 刘艳; 李从发

    2011-01-01

    The effects of different package methods, pre-storage methods, preservatives, and gibberellin on the storage of Hainan green oranges were studied at ambient temperature. The results showed that when they were washed using tap water, and soaked for lmin in the solution composed of 1000 mg/kg imazalil and 50 mg/kg gibberellin, and then packed by polyethylene film, Hainan green oranges could be stored for 28 d at ambient temperature (26~30%), with a good fruit rate of 93.3% and weight loss rate of 1.5% and green color in the pericarp.Prestorage and gibberellin were not good for the storage of Hainan green oranges.%本文主要研究包装方式,预贮、抑菌剂及赤霉素对海南绿橙常温下保鲜效果的影响,结果表明:抑霉唑1000mg/kg浸果1min,晾干后采用O.01mm厚的PE膜单果包装,常温(26~30℃)贮藏28d,好果率为93.3%,失重率为1.5%,果皮色泽青绿,果蒂新鲜,主要营养成分下降速度变缓;而预贮及赤霉素不适宜海南绿橙的采后处理.

  8. Analysis of multi-band pyrometry for emissivity and temperature measurements of gray surfaces at ambient temperature

    Science.gov (United States)

    Araújo, António

    2016-05-01

    A multi-band pyrometry model is developed to evaluate the potential of measuring temperature and emissivity of assumably gray target surfaces at 300 K. Twelve wavelength bands between 2 and 60 μm are selected to define the spectral characteristics of the pyrometers. The pyrometers are surrounded by an enclosure with known background temperature. Multi-band pyrometry modeling results in an overdetermined system of equations, in which the solution for temperature and emissivity is obtained through an optimization procedure that minimizes the sum of the squared residuals of each system equation. The Monte Carlo technique is applied to estimate the uncertainties of temperature and emissivity, resulting from the propagation of the uncertainties of the pyrometers. Maximum reduction in temperature uncertainty is obtained from dual-band to tri-band systems, a small reduction is obtained from tri-band to quad-band, with a negligible reduction above quad-band systems (a reduction between 6.5% and 12.9% is obtained from dual-band to quad-band systems). However, increasing the number of bands does not always reduce uncertainty, and uncertainty reduction depends on the specific band arrangement, indicating the importance of choosing the most appropriate multi-band spectral arrangement if uncertainty is to be reduced. A reduction in emissivity uncertainty is achieved when the number of spectral bands is increased (a reduction between 6.3% and 12.1% is obtained from dual-band to penta-band systems). Besides, emissivity uncertainty increases for pyrometers with high wavelength spectral arrangements. Temperature and emissivity uncertainties are strongly dependent on the difference between target and background temperatures: uncertainties are low when the background temperature is far from the target temperature, tending to very high values as the background temperature approaches the target temperature.

  9. Thermal behavior of human eye in relation with change in blood perfusion, porosity, evaporation and ambient temperature.

    Science.gov (United States)

    Rafiq, Aasma; Khanday, M A

    2016-12-01

    Extreme environmental and physiological conditions present challenges for thermal processes in body tissues including multi-layered human eye. A mathematical model has been formulated in this direction to study the thermal behavior of the human eye in relation with the change in blood perfusion, porosity, evaporation and environmental temperatures. In this study, a comprehensive thermal analysis has been performed on the multi-layered eye using Pennes' bio-heat equation with appropriate boundary and interface conditions. The variational finite element method and MATLAB software were used for the solution purpose and simulation of the results. The thermoregulatory effect due to blood perfusion rate, porosity, ambient temperature and evaporation at various regions of human eye was illustrated mathematically and graphically. The main applications of this model are associated with the medical sciences while performing laser therapy and other thermoregulatory investigation on human eye.

  10. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air

    Directory of Open Access Journals (Sweden)

    Jagdish Narayan

    2016-02-01

    Full Text Available We report a direct conversion of hexagonal boron nitride (h-BN into pure cubic boron nitride (c-BN by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN. The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.

  11. Research Update: Direct conversion of h-BN into pure c-BN at ambient temperatures and pressures in air

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, Jagdish, E-mail: narayan@ncsu.edu; Bhaumik, Anagh [Department of Materials Science and Engineering, Centennial Campus, North Carolina State University, Raleigh, North Carolina 27695-7907 (United States)

    2016-02-01

    We report a direct conversion of hexagonal boron nitride (h-BN) into pure cubic boron nitride (c-BN) by nanosecond laser melting at ambient temperatures and atmospheric pressure in air. According to the phase diagram, the transformation from h-BN into c-BN can occur only at high temperatures and pressures, as the hBN-cBN-Liquid triple point is at 3500 K/9.5 GPa. Using nanosecond laser melting, we have created super undercooled state and shifted this triple point to as low as 2800 K and atmospheric pressure. The rapid quenching from super undercooled state leads to formation of super undercooled BN (Q-BN). The c-BN phase is nucleated from Q-BN depending upon the time allowed for nucleation and growth.

  12. INFLUENCE OF COOLING RATE DURING QUENCHING ON IMPACT TOUGHNESS OF A HOT-WORK TOOL STEEL AT AMBIENT TEMPERATURE AND AT 200 °C

    Directory of Open Access Journals (Sweden)

    Henrik Jesperson

    2013-05-01

    Full Text Available Gross cracking of die-casting dies with inferior toughness sometimes occurs through too low preheating temperature and/or too slow cooling during quenching. This study aimed to clarify the influence of cooling rate on the toughness of the hot-work tool steel grade Uddeholm Vidar Superior at ambient temperature and at 200 °C, a typical preheating temperature for aluminium die-casting dies. Toughness was measured through instrumented Charpy V-notch impact testing. The decrease in energy absorption with increasing cooling time between 800°C and 500°C both at both ambient temperature and 200 °C was pronounced. At ambient temperature, the decrease in total energy was a consequence of a decrease in initiation energy whereas, at 200 °C, the decrease in total energy was due to a decrease in propagation energy.

  13. Solid-state ligand-driven light-induced spin change at ambient temperatures in bis(dipyrazolylstyrylpyridine)iron(II) complexes.

    Science.gov (United States)

    Takahashi, Kazuhiro; Hasegawa, Yuta; Sakamoto, Ryota; Nishikawa, Michihiro; Kume, Shoko; Nishibori, Eiji; Nishihara, Hiroshi

    2012-05-07

    We previously reported that an Fe(II) complex ligated by two (Z)-2,6-di(1H-pyrazol-1-yl)-4-styrylpyridine ligands (Z-H) presented a solid state ligand-driven light-induced spin change (LD-LISC) upon one-way Z-to-E photoisomerization, although modulation of the magnetism was trivial at ambient temperatures (Chem. Commun.2011, 47, 6846). Here, we report the synthesis of new derivatives of Z-H, Z-CN and Z-NO(2), in which electron-withdrawing cyano and nitro substituents are introduced at the 4-position of the styryl group to attain a more profound photomagnetism at ambient temperatures. Z-CN and Z-NO(2) undergo quantitative one-way Z-to-E photochromism upon excitation of the charge transfer band both in acetonitrile and in the solid state, similar to the behavior observed for Z-H. In solution, these substituents stabilized the low-spin (LS) states of Z-CN and Z-NO(2), and the behavior was quantitatively analyzed according to the Evans equation. The photomagnetic properties in the solid state, on the other hand, cannot be explained in terms of the substituent effect alone. Z-CN displayed photomagnetic properties almost identical to those of Z-H. Z-CN preferred the high-spin (HS) state at all temperatures tested, whereas photoirradiated Z-CN yielded a lower χ(M)T at ambient temperatures. The behavior of Z-NO(2) was counterintuitive, and the material displayed surprising photomagnetic properties in the solid state. Z-NO(2) occupied the LS state at low temperatures and underwent thermal spin crossover (SCO) with a T(1/2) of about 270 K. The photoirradiated Z-NO(2) displayed a higher value of χ(M)T and the modulation of χ(M)T exceeded that of Z-H or Z-CN. Z-NO(2)·acetone, in which acetone molecules were incorporated into the crystal lattice, further stabilized the LS state (T(1/2) > 300 K), thereby promoting large modulations of the χ(M)T values (87% at 273 K and 64% at 300 K) upon Z-to-E photoisomerization. Single crystal X-ray structure analysis revealed that

  14. Synthesis and Thermal Insulation Performance of Silica Aerogel from Recycled Coal Gangue by Means of Ambient Pressure Drying

    Institute of Scientific and Technical Information of China (English)

    ZHU Pinghua; ZHENG Meng; ZHAO Shanyu; WU Junyong; XU Haixun

    2015-01-01

    Silica aerogel materials are well recognized for their superinsulation performance and are regarded as one of the hot candidates to revolutionize building insulation. To date, high production cost related to exorbitant precursors as well as cumbrous multi-step hydrophobization process has often narrowed the ifeld of applications. In this work, granular silica aerogel materials were synthesized by extracting SiO2from recycled rich silicon coal gangue, followed by one-step hydrophobization and ambient pressure drying. Lightweight (about 0.16 g/cm3) and nanostructural aerogels were obtained through this route. They exhibit a 3D open porous microstructure with around 600 cm2/g surface area and 20 nm of the average pore diameter, thermal conductivity of 4-5 mm packed granules is 20-25 mW/(m·K), which was proved by both guarded hot plate and hot-wire transient methods. This study offers a new facile route for the synthesis of silica aerogel from recycled solid waste coal gangue and suggests a method, which may lead to a cost reduction in terms of industrial production.

  15. Model Study of the Influence of Ambient Temperature and Installation Types on Surface Temperature Measurement by Using a Fiber Bragg Grating Sensor.

    Science.gov (United States)

    Liu, Yi; Zhang, Jun

    2016-07-01

    Surface temperature is an important parameter in clinical diagnosis, equipment state control, and environmental monitoring fields. The Fiber Bragg Grating (FBG) temperature sensor possesses numerous significant advantages over conventional electrical sensors, thus it is an ideal choice to achieve high-accuracy surface temperature measurements. However, the effects of the ambient temperature and installation types on the measurement of surface temperature are often overlooked. A theoretical analysis is implemented and a thermal transfer model of a surface FBG sensor is established. The theoretical and simulated analysis shows that both substrate strain and the temperature difference between the fiber core and hot surface are the most important factors which affect measurement accuracy. A surface-type temperature standard setup is proposed to study the measurement error of the FBG temperature sensor. Experimental results show that there are two effects influencing measurement results. One is the "gradient effect". This results in a positive linear error with increasing surface temperature. Another is the "substrate effect". This results in a negative non-linear error with increasing surface temperature. The measurement error of the FBG sensor with single-ended fixation are determined by the gradient effect and is a linear error. It is not influenced by substrate expansion. Thus, it can be compensated easily. The measurement errors of the FBG sensor with double-ended fixation are determined by the two effects and the substrate effect is dominant. The measurement error change trend of the FBG sensor with fully-adhered fixation is similar to that with double-ended fixation. The adhesive layer can reduce the two effects and measurement error. The fully-adhered fixation has lower error, however, it is easily affected by substrate strain. Due to its linear error and strain-resistant characteristics, the single-ended fixation will play an important role in the FBG sensor

  16. Effects of temperature, algae biomass and ambient nutrient on the absorption of dissolved nitrogen and phosphate by Rhodophyte Gracilaria asiatica

    Science.gov (United States)

    Du, Rongbin; Liu, Liming; Wang, Aimin; Wang, Yongqiang

    2013-03-01

    Gracilaria asiatica, being highly efficient in nutrient absorption, is cultivated in sea cucumber ponds to remove nutrients such as nitrogen and phosphate. It was cultured in a laboratory simulating field conditions, and its nutrient absorption was measured to evaluate effects of environmental conditions. Ammonia nitrogen (AN), nitrate nitrogen (NN), total inorganic nitrogen (TIN), and soluble reactive phosphorus (SRP) uptake rate and removal efficiency were determined in a 4×2 factorial design experiment in water temperatures ( T) at 15°C and 25°C, algae biomass (AB) at 0.5 g/L and 1.0 g/L, total inorganic nitrogen (TIN) at 30 μmol/L and 60 μmol/L, and soluble reactive phosphorus (SRP) at 3 and 6 μmol/L. AB and ambient TIN or SRP levels significantly affected uptake rate and removal efficiency of AN, NN, TIN, and SRP ( P< 0.001). G. asiatica in AB of 0.5 g/L showed higher uptake rate and lower removal efficiency relative to that with AB of 1.0 g/L. Nitrogen and phosphorus uptake rate rose with increasing ambient nutrient concentrations; nutrient removal efficiency decreased at higher environmental nutrient concentrations. The algae preferred to absorb AN to NN. Uptake rates of AN, NN, and SRP were significantly affected by temperature ( P < 0.001); uptake rate was higher for the 25°C group than for the 15°C group at the initial experiment stage. Only the removal efficiency of AN and SRP showed a significant difference between the two temperature groups ( P< 0.01). The four factors had significant interactive effects on absorption of N and P, implying that G. asiatica has great bioremedial potential in sea cucumber culture ponds.

  17. Effects of temperature, algae biomass and ambient nutrient on the absorption of dissolved nitrogen and phosphate by Rhodophyte Gracilaria asiatica

    Institute of Scientific and Technical Information of China (English)

    DU Rongbin; LIU Liming; WANG Aimin; WANG Yongqiang

    2013-01-01

    Gracilaria asiatica,being highly efficient in nutrient absorption,is cultivated in sea cucumber ponds to remove nutrients such as nitrogen and phosphate.It was cultured in a laboratory simulating field conditions,and its nutrient absorption was measured to evaluate effects of environmental conditions.Ammonia nitrogen (AN),nitrate nitrogen (NN),total inorganic nitrogen (TIN),and soluble reactive phosphorus (SRP) uptake rate and removal efficiency were determined in a 4x2 factorial design experiment in water temperatures (T) at 15℃ and 25℃,algae biomass (AB) at 0.5 g/L and 1.0 g/L,total inorganic nitrogen (TIN) at 30 μmol/L and 60 μmol/L,and soluble reactive phosphorus (SRP) at 3 and 6 μmol/L.AB and ambient TIN or SRP levels significantly affected uptake rate and removal efficiency of AN,NN,TIN,and SRP (P<0.001).G.asiatica in AB of 0.5 g/L showed higher uptake rate and lower removal efficiency relative to that with AB of 1.0 g/L.Nitrogen and phosphorus uptake rate rose with increasing ambient nutrient concentrations; nutrient removal efficiency decreased at higher environmental nutrient concentrations.The algae preferred to absorb AN to NN.Uptake rates of AN,NN,and SRP were significantly affected by temperature (P<0.001); uptake rate was higher for the 25℃ group than for the 15℃ group at the initial experiment stage.Only the removal efficiency of AN and SRP showed a significant difference between the two temperature groups (P<0.01).The four factors had significant interactive effects on absorption of N and P,implying that G.asiatica has great bioremedial potential in sea cucumber culture ponds.

  18. Influence of ambient temperatures on metabolic responses of Murrah buffaloes of varying physiological states from arid tracts in India

    Directory of Open Access Journals (Sweden)

    Ashish Joshi

    2012-12-01

    Full Text Available Ambient temperature associated variations in metabolic responses of Murrah breed ofbuffaloes of varying physiological states belonging to arid tracts were investigated. Healthy adultfemale Murrah buffaloes were grouped according to physiological states into group A (non-pregnantmilch, pregnant milch and pregnant dry and group B (primipara and multipara and blood sampleswere collected during moderate, hot and cold environmental temperature periods to obtain sera.Metabolic responses were assessed by analyzing serum urea, creatinine, total proteins, cholesterol,triglycerides and glucose and the moderate mean values were 5.18±0.04 mmol L-1, 118.00±1.00 μmolL-1, 71.00±0.12 gL-1, 3.30±0.02 mmol L-1, 1.28±0.01 mmol L-1 and 3.7±0.02 mmol L-1, respectively.The mean values of serum urea and creatinine were significantly (p≤0.05 higher during hot and coldambiences, the mean value of total serum proteins and triglycerides were significantly (p≤0.05 lowerduring hot and cold ambiences and the mean values of cholesterol and glucose were significantly(p≤0.05 lower during hot ambience and significantly (p≤0.05 higher during cold ambience ascompared to respective moderate mean value. The mean values of non pregnant milch, pregnant milchand pregnant dry animals differed significantly (p≤0.05 from each other in all the environmentalperiods. It was concluded that extreme hot and cold ambient temperatures affected the buffaloes ofall physiological states which was evident in the form of variations in the metabolic responses tocombat the environmental challenges.

  19. Single step low temperature synthesis of gadolinium gallium garnet nanopowders

    Institute of Scientific and Technical Information of China (English)

    Rekha Mann; Kiranmala Laishram; Neelam Malhan

    2012-01-01

    Solution combustion synthesis of single-phase gadolinium gallium oxide (Gd3Ga5O12,GGG) nanopowders,by a fuel mixture approach using urea and glycine at a low temperature of 500 ℃,was being reported for the first time.Based on the fact that urea and glycine are good fuels for gallium oxide and gadolinium oxide synthesis,the fuel mixture composition was obtained,which could lead to direct phase pure cubic Gd3Ga5O12 formation without any subsequent calcination step.Combustion was carried out in furnace pre-heated at 500 ℃.Thermogravimetric analysis (TGA) of combustion product showed negligible mass loss indicating direct formation of GGG powder.Fourier transform infrared (FTIR) spectrum of combusted product showed peak characteristic of GGG in case of mixed fuel.X-ray diffraction (XRD) confirmed formation of phase pure GGG at 500 ℃ in preheated furnace.Very fine,well dispersed nanometric particles of size range of 50-100 nm were obtained,being uniform and close to spherical morphology as observed by transmission electron microscope (TEM).

  20. Synthesis of tungsten oxide nanoparticles using a hydrothermal method at ambient pressure

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Younesi, Reza; Guinel, Maxime J-F

    2014-01-01

    ) nanoparticles were synthesized using a simple and inexpensive low temperature and low pressure hydrothermal (HT) method. The precursor solution used for the HT process was prepared by adding hydrochloric acid to diluted sodium tungstate solutions (Na2WO4 center dot 2H(2)O) at temperatures below 5 degrees C...... of WO3 nanoparticles using this method is therefore a three step process: protonation of tungstate ions, crystallization of tungstite, and phase transformation to WO3. Furthermore, this process can be tailored. For example, we show that WO3 can be doped with cesium and that nanorods can also be obtained......Tungsten oxide (WO3) nanostructures receive sustained interest for a wide variety of applications, and especially for its usage as a photocatalyst. It is therefore important to find suitable methods allowing for its easy and inexpensive large scale production. Tungstite (WO3 center dot H2O...

  1. Physical exercise-induced changes in the core body temperature of mice depend more on ambient temperature than on exercise protocol or intensity

    Science.gov (United States)

    Wanner, Samuel Penna; Costa, Kátia Anunciação; Soares, Anne Danieli Nascimento; Cardoso, Valbert Nascimento; Coimbra, Cândido Celso

    2014-08-01

    The mechanisms underlying physical exercise-induced hyperthermia may be species specific. Therefore, the present study aimed to investigate the effects of exercise intensity and ambient temperature on the core body temperature ( T core) of running mice, which provide an important experimental model for advancing the understanding of thermal physiology. We evaluated the influence of different protocols (constant- or incremental-speed exercises), treadmill speeds and ambient temperatures ( T a) on the magnitude of exercise-induced hyperthermia. To measure T core, a telemetric sensor was implanted in the abdominal cavity of male adult Swiss mice under anesthesia. After recovering from the surgery, the animals were familiarized to running on a treadmill and then subjected to the different running protocols and speeds at two T a: 24 °C or 34 °C. All of the experimental trials resulted in marked increases in T core. As expected, the higher-temperature environment increased the magnitude of running-induced hyperthermia. For example, during incremental exercise at 34 °C, the maximal T core achieved was increased by 1.2 °C relative to the value reached at 24 °C. However, at the same T a, neither treadmill speed nor exercise protocol altered the magnitude of exercise-induced hyperthermia. We conclude that T core of running mice is influenced greatly by T a, but not by the exercise protocols or intensities examined in the present report. These findings suggest that the magnitude of hyperthermia in running mice may be regulated centrally, independently of exercise intensity.

  2. Room Temperature Synthesis of Magnetite (Fe3-δO4) Nanoparticles by a Simple Reverse Co-Precipitation Method

    Science.gov (United States)

    Mahmed, N.; Heczko, O.; Söderberg, O.; Hannula, S.-P.

    2011-10-01

    Magnetite (Fe3-δO4) nanoparticles with the size less than 30 nm have been synthesized by using a simple reverse co-precipitation method at room temperature. During the process, ferrous sulfate (FeSO4·7H2O) powder was used as an iron precursor, and ammonium hydroxide (NH4OH) as a precipitating agent. The experiment was carried out in ambient atmosphere without any surfactant added. In this method, the base solution for the precipitation process was adjusted to have a pH value suitable for the formation of the magnetite phase. The iron salt precursor was added into the solution during the synthesis by two different synthesis protocols. The phase, morphology and magnetic characteristic of differently synthesized magnetite particles were characterized by using an X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The morphologies of the particles were spherical or irregular in shape depending on the synthesis protocol used. Magnetic measurement shows that the particles are ferromagnetic at room temperature with relatively high saturation magnetization and low hysteresis. The saturation magnetization and magnetic hysteresis of the particles varied with preparation reaction conditions and the resulting oxidation state of the particles.

  3. Epitaxial growth of MgB2 films at ambient temperature

    Science.gov (United States)

    Shishido, Hiroaki; Yoshida, Takuya; Nakagami, Takatoshi; Ishida, Takekazu

    We grew crystalline MgB2 thin films using molecular beam epitaxy at a low substrate temperature of 110 °C under an ultrahigh vacuum of about 10-6 Pa. MgB2 thin films were deposited on the (001) surface of a 4H-SiC substrate with an epitaxial Mg buffer layer. The epitaxial growth was confirmed by X-ray diffraction measurements. MgB2 thin films show a sharp superconducting transition at 27.2 K, with a relatively narrow superconducting transition width ΔTc = 0.9 K. The growth temperature was lower than any in prior reports on superconducting MgB2 thin films. The presence of the epitaxial Mg buffer layer is crucial for reducing the epitaxial temperature.

  4. Room temperature synthesis and high temperature frictional study of silver vanadate nanorods.

    Science.gov (United States)

    Singh, D P; Polychronopoulou, K; Rebholz, C; Aouadi, S M

    2010-08-13

    We report the room temperature (RT) synthesis of silver vanadate nanorods (consisting of mainly beta-AgV O(3)) by a simple wet chemical route and their frictional study at high temperatures (HT). The sudden mixing of ammonium vanadate with silver nitrate solution under constant magnetic stirring resulted in a pale yellow coloured precipitate. Structural/microstructural characterization of the precipitate through x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the high yield and homogeneous formation of silver vanadate nanorods. The length of the nanorods was 20-40 microm and the thickness 100-600 nm. The pH variation with respect to time was thoroughly studied to understand the formation mechanism of the silver vanadate nanorods. This synthesis process neither demands HT, surfactants nor long reaction time. The silver vanadate nanomaterial showed good lubrication behaviour at HT (700 degrees C) and the friction coefficient was between 0.2 and 0.3. HT-XRD revealed that AgV O(3) completely transformed into silver vanadium oxide (Ag(2)V(4)O(11)) and silver with an increase in temperature from RT to 700 degrees C.

  5. Study on Desulfurization Efficiency and Products of Ce-Doped Nanosized ZnO Desulfurizer at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Li Fen; Yan Bo; Zhang Jie; Jiang Anxi; Shao Chunhong; Kong Xiangji; Wang Xin

    2007-01-01

    Ce-doped nanosized ZnO desulfurizer was prepared by homogeneous precipitation, and its desulfurization efficiency at ambient temperature was investigated through dynamic experiments. The results showed that the desulfurization activity of nanosized Ce-ZnO had improved greatly, compared to nanosized ZnO desulfurizer. Nanosized Ce-ZnO desulfurizer was characterized by XRD, TPD-MS, XPS, and TEM. The research results indicated that doping Ce decreased the particle size of the nanosized ZnO desulfurizer and ZnS was the principal desulfurization product. There were adsorption complexes of HS and S on the surface of desulfurizer as well. Only a small amount of vapor appeared in the tail gas on the condition of meeting the precision of desulfurization.

  6. Facile palladium catalyzed Suzuki-Miyaura coupling in air and water at ambient temperature

    KAUST Repository

    Marziale, Alexander N.

    2010-01-01

    A new palladacyclic catalyst yields high activities in aqueous Suzuki-Miyaura coupling at room temperature. Using an optimized protocol, a broad range of products can be isolated in good to excellent yields and high purity by simple filtration. © 2010 The Royal Society of Chemistry.

  7. Predator-released compounds, ambient temperature and competitive exclusion among differently sized Daphnia species

    NARCIS (Netherlands)

    Vijverberg, J.; Vos, Matthijs

    2006-01-01

    1. We studied the effects of fish water and temperature on mechanisms of competitive exclusion among two Daphnia species in flow-through microcosms. The large-bodied D. pulicaria outcompeted the medium sized D. galeata × hyalina in fish water, but not in the control treatment. Daphnia galeata × hyal

  8. Fundamental Studies on Ambient Temperature Creep Deformation Behavior of Alpha and Alpha-Beta Titanium Alloys

    Science.gov (United States)

    2013-01-31

    Electron Microscope Elemental tin t time T Ta temperature Elemental Tantalum TEM Ti Transmission Electron Microscope Elemental titanium Ti...7 [45] and 8 [46]. The chemical compositions are actual chemical compositions of the alloys after fabrication as determined by the wet chemistry

  9. Impacts of Ambient Temperature and Pressure on PM2.5 Emission Profiles of Light-Duty Diesel Vehicles

    Science.gov (United States)

    Wang, Chenyu; Wu, Ye; Li, Zhenhua; Hao, Jiming

    2012-01-01

    The impact of the environmental factors on the emissions of particulate matter (PM) number, size distribution and mass size distribution from diesel passenger cars was evaluated. Particle measurements from five modern light-duty diesel vehicles (LDDV) were performed in June and November 2011. Commercial low sulfur diesel fuel (less than 50 ppm) was used during the testing of these vehicles which were not equipped with after-treatment devices. The dynamometer test was based on the Economic Commission of Europe (ECE) 15 cycles. The results indicate that PM2.5 emissions from LDDV are significantly affected by ambient temperature and pressure. A comparison of the emissions concentration of PM2.5 in these two different months showed that the number concentration in June was (3.8 ± 0.69) × 107 cm-3 and (2.5 ± 0.66) × 107 cm-3 in November. The PM concentration of about 30 nm diameter was 25 ± 6% of the total emissions in November while only 14 ± 3% of total emissions in June. In the 60 nm to 2.5 μm test range, November data shows less of a contribution for number than data from June testing. The concentration of mass emissions in June was (325 ± 44) mg/m3 and (92 ± 30) mg/m3 in November. The contribution of the number of PM particles in November testing is lower than testing in June by 34% and the mass concentration in November is 70% lower than that in June. With the decrease of ambient temperature and the increase of ambient pressure, both the oxygen concentration in cylinder and air-fuel ratio are increased, which caused lower particle number and mass emissions during November testing. The size distribution is also altered by these changes: the more efficient in-cylinder combustion resulted in a higher proportion of particles in the 30 nm and smaller range than for other particle sizes.

  10. Rechargeable lithium battery employing a new ambient temperature hybrid polymer electrolyte based on PVK+PVdF-HFP (copolymer)

    Science.gov (United States)

    Michael, M. S.; Prabaharan, S. R. S.

    We describe here for the first time, our recent success in developing an ambient temperature Li + conducting solid polymer electrolyte (SPE) using the concept of polymer alloying upon blending two thermoplastic polymers such as poly(vinylidene) fluoride-hexafluoropropylene (PVdF-HFP-copolymer) and poly( N-vinylcarbazole), PVK and achieved the room temperature electrolytic conductivity ( σi) of 0.7×10 -3 S/cm for a typical composition of PVdF-HFP copolymer/PVK blend mixed with EC/LiBF 4 molar composition. The ionic transference number of 0.49 was deduced from combined ac-impedance and dc polarization method. High-resolution optical microscopic examination revealed the disappearance of characteristic highly porous surface structure of PVdF-HFP matrix upon blending with PVK leading to the formation of resultant PVdF-HFP/PVK blend polymer alloy. The electrochemical stability of the polymer electrolyte membrane thus obtained was found to be stable up to ˜4.7 V versus Li/Li +. The new hybrid alloy polymer electrolyte membrane was found to exhibit good interfacial properties against lithium metal and thus, it was found to aid the room temperature operation as electrolytic membrane cum separator in all-solid state rechargeable lithium polymer test cell, LiCo 0.8Ni 0.2O 2/SPE/Li.

  11. A high-temperature, ambient-pressure ultra-dry operando reactor cell for Fourier-transform infrared spectroscopy

    Science.gov (United States)

    Köck, Eva-Maria; Kogler, Michaela; Pramsoler, Reinhold; Klötzer, Bernhard; Penner, Simon

    2014-08-01

    The construction of a newly designed high-temperature, high-pressure FT-IR reaction cell for ultra-dry in situ and operando operation is reported. The reaction cell itself as well as the sample holder is fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high-temperature zone. Special emphasis was put on chemically absolute water-free and inert experimental conditions, which includes reaction cell and gas-feeding lines. Operation and spectroscopy up to 1273 K is possible, as well as pressures up to ambient conditions. The reaction cell exhibits a very easy and variable construction and can be adjusted to any available FT-IR spectrometer. Its particular strength lies in its possibility to access and study samples under very demanding experimental conditions. This includes studies at very high temperatures, e.g., for solid-oxide fuel cell research or studies where the water content of the reaction mixtures must be exactly adjusted. The latter includes all adsorption studies on oxide surfaces, where the hydroxylation degree is of paramount importance. The capability of the reaction cell will be demonstrated for two selected examples where information and in due course a correlation to other methods can only be achieved using the presented setup.

  12. Characterization of membrane foulants at ambient temperature anaerobic membrane bioreactor treating low-strength industrial wastewater

    DEFF Research Database (Denmark)

    Zarebska, Agata; Kjerstadius, Hamse; Petrinic, Irena

    2016-01-01

    with anaerobic biological treatment at low temperature could not only reduce the operational cost of AD, but also alleviate environmental problems. However, at low temperature the AnMBR may suffer more fouling due to the increased extracellular polymeric substances production excreted by bacteria hampering......The large volume of industrial low-strength wastewaters has a potential for biogas production through conventional anaerobic digestion (AD), limited though by the need of heating and concentrating of the wastewaters. The use of anaerobic membrane bioreactor (AnMBR) combining membrane filtration...... the application of the process for the industrial wastewater treatment. In order to solve or reduce the fouling problem it is necessary to have a good insight into the processes that take place both on and in the membrane pores during filtration. Therefore, the objective of this study is to contribute to a better...

  13. Heterogeneous Palladium Chloride Catalyzed Ligand-free Suzuki-Miyaura Coupling Reactions at Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    WANG Min; WANG Lei

    2008-01-01

    A mild and efficient ligand-free Suzuki-Miyaura coupling reaction catalyzed by heterogeneous palladium chloride was developed at room temperature in a short reaction time under air atmosphere.Various phenyl iodides,bromides and activated chlorides were coupled with sodium tetraphenylborate or phenylboronic acids efficiently to afford the corresponding cross-coupled products in good to excellent yields.Furthermore,the catalyst could be recycled up to four times without loss of its activity.

  14. Ambient organic carbon to elemental carbon ratios: Influence of the thermal–optical temperature protocol and implications

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yuan, E-mail: ycheng@mail.tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing (China); He, Ke-bin, E-mail: hekb@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing (China); State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing (China); Duan, Feng-kui; Du, Zhen-yu [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing (China); Zheng, Mei [College of Environmental Sciences and Engineering, Peking University, Beijing (China); Ma, Yong-liang [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing (China)

    2014-01-01

    Ambient organic carbon (OC) to elemental carbon (EC) ratios are strongly associated with not only the radiative forcing due to aerosols but also the extent of secondary organic aerosol (SOA) formation. An inter-comparison study was conducted based on fine particulate matter samples collected during summer in Beijing to investigate the influence of the thermal–optical temperature protocol on the OC to EC ratio. Five temperature protocols were used such that the NIOSH (National Institute for Occupational Safety and Health) and EUSAAR (European Supersites for Atmospheric Aerosol Research) protocols were run by the Sunset carbon analyzer while the IMPROVE (the Interagency Monitoring of Protected Visual Environments network)-A protocol and two alternative protocols designed based on NIOSH and EUSAAR were run by the DRI analyzer. The optical attenuation measured by the Sunset carbon analyzer was more easily biased by the shadowing effect, whereas total carbon agreed well between the Sunset and DRI analyzers. The EC{sub IMPROVE-A} (EC measured by the IMPROVE-A protocol; similar hereinafter) to EC{sub NIOSH} ratio and the EC{sub IMPROVE-A} to EC{sub EUSAAR} ratio averaged 1.36 ± 0.21 and 0.91 ± 0.10, respectively, both of which exhibited little dependence on the biomass burning contribution. Though the temperature protocol had substantial influence on the OC to EC ratio, the contributions of secondary organic carbon (SOC) to OC, which were predicted by the EC-tracer method, did not differ significantly among the five protocols. Moreover, the SOC contributions obtained in this study were comparable with previous results based on field observation (typically between 45 and 65%), but were substantially higher than the estimation provided by an air quality model (only 18%). The comparison of SOC and WSOC suggests that when using the transmittance charring correction, all of the three common protocols (i.e., IMPROVE-A, NIOSH and EUSAAR) could be reliable for the estimation

  15. Synthesis of manganese spinel nanoparticles at room temperature by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Giovannelli, F., E-mail: fabien.giovannelli@univ-tours.fr [GREMAN, UMR 7347 CNRS-CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 BLOIS (France); Autret-Lambert, C.; Mathieu, C.; Chartier, T.; Delorme, F. [GREMAN, UMR 7347 CNRS-CEA, Universite Francois Rabelais, 15 rue de la chocolaterie, 41000 BLOIS (France); Seron, A [BRGM, 3 Avenue Claude Guillemin, BP 36009, 45060 ORLEANS Cedex 2 (France)

    2012-08-15

    This paper is focused on a new route to synthesize Mn{sub 3}O{sub 4} nanoparticles by alkalisation by sodium hydroxide on a manganeous solution at room temperature. The precipitates obtained at different pH values have been characterized by XRD and TEM. Since the first addition of sodium hydroxide, a white Mn(OH){sub 2} precipitate appears. At pH=7, {gamma}-MnOOH phase is predominant with needle like shaped particles. At pH=10, hausmanite nanoparticles, which exhibits well defined cubic shape in the range 50-120 nm are obtained. This new precipitation route is a fast and easy environmentally friendly process to obtain well crystallized hausmanite nanoparticles. - Graphical abstract: TEM image showing Mn{sub 3}O{sub 4} particles after a precipitation at pH=10. Highlights: Black-Right-Pointing-Pointer A new route to synthesize Mn{sub 3}O{sub 4} nanoparticles has been demonstrated. Black-Right-Pointing-Pointer Synthesis has been performed by precipitation at room temperature. Black-Right-Pointing-Pointer The size of the Mn{sub 3}O{sub 4} nanoparticles is between 50 and 120 nm.

  16. Synthesis of iron oxide nanorods via chemical scavenging and phase transformations of intermediates at ambient conditions

    Science.gov (United States)

    Deshmukh, Ruchi; Mehra, Anurag; Thaokar, Rochish

    2017-01-01

    Chemically induced shape transformations of isotropic seeds, comprised of iron oxyhydroxides and iron oxide borate into nanorods, is reported. Transient growth studies show that the nanorods are formed via phase transformation and aggregation of various metastable species. Addition of tetra- methyl-ammonium hydroxide (TMAH) to the in situ synthesized seeds ensures a typical reaction pathway that favors formation of magnetite (Fe 3 O 4) via the steps of chemical etching, phase transformation of intermediates, and crystal consolidation. Whereas, with addition of sodium hydroxide (NaOH), either magnetite (Fe 3 O 4) or a mixture of ( γ-Fe 2 O 3 + α-FeOOH) is obtained. The shape with both the additives is always that of nanorods. When the seeds treated with TMAH were aged in an ultrasonication bath, rods with almost twice the length and diameter (length = 2800 nm, diameter = 345 nm) are obtained as compared to the sample aged without ultrasonication (length = 1535 nm, diameter = 172 nm). The morphology of nanostructures depending upon other experimental conditions such as, aging the sample at 60 ∘C, seeds synthesized under ultrasonication/ stirring or externally added are also examined and discussed in detail. All the samples show high coercivity and strong ferromagnetic behavior at room temperature and should be promising candidates as ferro-fluids for various applications.

  17. Dynamic instability at the origin of oxygen ion conduction in solid oxides at ambient temperature

    Indian Academy of Sciences (India)

    Helmut Schober; Werner Paulus; Tanguy Berthier; Olivier Hernandez; Monica Ceretti; Stefan Eibl; Mark Johnson; Marie Plazanet; Carlo Lamberti

    2008-11-01

    The conduction of ions in solids is of paramount importance for many technological devices like solid oxide fuel cells. It is inherent to solids that ions are trapped within potential wells. Their transport thus has to be activated at the price of elevated temperatures, a condition that is often incompatible with technological applications. While atomic vibrations have the potential of assisting the diffusion process, little is known about the exact conditions that have to be reunited to trigger such a process. Here we show that dynamic instability is responsible for the large ion conduction in SrFeO2.5 with brownmillerite-type structure. Using ab-initio molecular dynamics calculations we observe the migration of oxygen ions away from the original lattice positions into the vacancy channels of the brownmillerite structure. The escape of the oxygen ion is rendered possible by the destabilization of a shallow potential well due to low-lying vibrational modes, the existence of which is confirmed by neutron spectroscopy. Analysing the lattice dynamics as a function of structural parameters it is possible to identify the structural subtleties responsible for the instability. It is found that in the isostructural compound CaFeO2.5, fast oxygen ion diffusion is absent at low temperatures. The origin of this behaviour lies with the slightly different iron–oxygen distances rendering the potentials better defined and less amenable to dynamical destabilization. The here-introduced concept of dynamical instability is not restricted to the discussed class of materials but may be applied to any system that features ion conduction at low temperatures.

  18. An Ambient Temperature Molten Sodium-Vanadium Battery with Aqueous Flowing Catholyte.

    Science.gov (United States)

    Liu, Caihong; Shamie, Jack S; Shaw, Leon L; Sprenkle, Vincent L

    2016-01-20

    In this study, we have investigated the key factors dictating the cyclic performance of a new type of hybrid sodium-based flow batteries (HNFBs) that can operate at room temperature with high cell voltages (>3 V), multiple electron transfer redox reactions per active ion, and decoupled design of power and energy. HNFBs are composed of a molten Na-Cs alloy anode, flowing aqueous catholyte, and a Na-β″-Al2O3 solid electrolyte as the separator. The surface functionalization of graphite felt electrodes for the flowing aqueous catholyte has been studied for its effectiveness in enhancing V(2+)/V(3+), V(3+)/V(4+), and V(4+)/V(5+) redox couples. The V(4+)/V(5+) redox reaction has been further investigated at different cell operation temperatures for its cyclic stability and how the properties of the solid electrolyte membrane play a role in cycling. These fundamental understandings provide guidelines for improving the cyclic performance and stability of HNFBs with aqueous catholytes. We show that the HNFB with aqueous V-ion catholyte can reach high storage capacity (∼70% of the theoretical capacity) with good Coulombic efficiency (90% ± 1% in 2-30 cycles) and cyclic performance (>99% capacity retention for 30 cycles). It demonstrates, for the first time, the potential of high capacity HNFBs with aqueous catholytes, good capacity retention and long cycling life. This is also the first demonstration that Na-β″-Al2O3 solid electrolyte can be used with aqueous electrolyte at near room temperature for more than 30 cycles.

  19. The Effect of Ambient Temperature and Exercise to the Level of Exhaustion on

    Directory of Open Access Journals (Sweden)

    Somaye Kasharafifard

    2014-06-01

    Full Text Available Background: The increase in the amount of heat shock protein and C-reactive protein occurring as a result of stress was done with the aims of returning cell homeostasis, successful restoration of cell injury and protection of cell against more injuries. Materials and Methods: Fifteen climber and 15 non athlete subjects were chosen. A selected aerobic test was done by the subjects using Monark bicycle under two different conditions. Before starting the test, the subjects were exposed to a normal condition with the temperature of 24±2°C for an hour and a blood sample was taken from all the subjects. Then immediately, the subjects took the selected aerobic test to the level of exhaustion and blood sample was taken again. A week later, these subjects were exposed to a heated environment with the temperature of 38±2°C, followed by blood sample taking. Finally, the test was done by the subjects to the level of exhaustion and the last blood sample was taken. Then, the amount of heat shock protein (HSP and C - reactive protein (CRP in blood samples was measured. Results: A meaningful difference was observed in the changes of heat shock proteins (p=0.012 and C-reactive protein (p=0.02 between athlete and non athlete subjects. There was no meaningful difference in CRP and HSP in normal and hot condition for non athlete subjects before and after the test. But the result of the study demonstrates that There was a meaningful difference for athletes in both conditions before and after the test (p=0.002. Conclusion: Based on the study, it is claimed that while an athlete is exposed to several stressful conditions (e.g. high temperature and physical exercise, compared to a non athlete, the reaction of his body cells is more significant in order to prevent the injury.

  20. Evaluation and Response of Aged Flexible Airfield Pavements at Ambient Temperatures Using the Falling Weight Deflectometer

    Science.gov (United States)

    1988-01-01

    3) accessibilty to the airfield, especially during the day, was virtually unlimited, 4) the entire airfield, excluding parking aprons, was comprised...role. 135 LU C4 Cy! C CU 0 C*4O LU - CC-) 0 - AUla j? cc IL 0 01 tn in P4 4 Lui ( tn to4- .~0 N U LLL 0m Sr CHAPTER 6 ANALYSES OF FIELD MEASURED FWD...tempera- tures were virtually the same for both sites. This showed that as the degree of cracking in the asphalt concrete diminished, temperature

  1. Dependence of nitrogen concentration in type Ib diamonds on synthesis temperature

    Institute of Scientific and Technical Information of China (English)

    TIAN Yu; JIA XiaoPeng; ZANG ChuanYi; LI ShangSheng; XIAO HongYu; ZHANG YaFei; HUANG GuoFeng; LI Rui; HAN QiGang; MA LiQiu; LI Yong; CHEN XiaoZhou; ZHANG Chong; MA HongAn

    2009-01-01

    Type Ib diamonds were grown by the temperature gradient method (TGM) at 5.5 GPa and 1500-1560 K in a china-type cubic anvil high pressure apparatus using Ni70Mn25Co5 alloy as solvent/catalyst. The concentration of nitrogen (CN) in type Ib diamonds synthesized at different synthesis temperatures was measured by a Fourier transform infrared (FTIR) spectrometer. The dependence of CN in diamond on synthesis temperature was studied. For the type Ib diamonds synthesized using Ni70Mn25Co5 as catalyst, its CN decreases along with the increase of synthesis temperature.

  2. Effect of surrogate aggregates on the thermal conductivity of concrete at ambient and elevated temperatures.

    Science.gov (United States)

    Yun, Tae Sup; Jeong, Yeon Jong; Youm, Kwang-Soo

    2014-01-01

    The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Four different measurement methods are used to assess the reliability of the thermal data and to evaluate the effects of the various sensor types. The concrete specimens are also assessed at every 100 °C during heating to ~800 °C. Normal concrete is shown to have a thermal conductivity of ~2.25 W m(-1) K(-1). The surrogate aggregates effectively reduce the conductivity to ~1.25 W m(-1) K(-1) at room temperature. The aggregate size is shown not to affect thermal conduction: fine and coarse aggregates each lead to similar results. Surface contact methods of assessment tend to underestimate thermal conductivity, presumably owing to high thermal resistance between the transducers and the specimens. Thermogravimetric analysis shows that the stages of mass loss of the cement paste correspond to the evolution of thermal conductivity upon heating.

  3. Seasonality, ambient temperatures and hospitalizations for acute exacerbation of COPD: a population-based study in a metropolitan area

    Directory of Open Access Journals (Sweden)

    Almagro P

    2015-05-01

    Full Text Available Pere Almagro,1 Carme Hernandez,2,3,7 Pable Martinez-Cambor,4,5 Ricard Tresserras,2,6 Joan Escarrabill2,7 1Acute Geriatric Care Unit, Internal Medicine, University Hospital Mútua de Terrasa, University of Barcelona, Barcelona, Spain; 2Respiratory Disease Management Plan, Department of Health of the Autonomous Government of Catalonia, Observatory of Respiratory Therapy, 3Integrated Care Unit, Medical and Nursing Management, Hospital Clínic Barcelona, Barcelona, 4Oficina de Investigación Biosanitaria de Oviedo, Asturias, Spain; 5Universidad Autonoma de Chile, Santiago, Chile; 6Health Department, 7Chronic Diseases Care Program, Hospital Clinic, Hospital Clínic & REDISSEC (Health Services Research on Chronic Patients Network, Barcelona, Spain Background: Excluding the tropics, exacerbations of chronic obstructive pulmonary disease (COPD are more frequent in winter. However, studies that directly relate hospitalizations for exacerbation of COPD to ambient temperature are lacking. The aim of this study was to assess the influence of temperature on the number of hospitalizations for COPD.Methods: This was a population-based study in a metropolitan area. All hospital discharges for acute exacerbation of COPD during 2009 in Barcelona and its metropolitan area were analyzed. The relationship between the number of hospitalizations for COPD and the mean, minimum, and maximum temperatures alongside comorbidity, humidity, influenza rate, and environmental pollution were studied.Results: A total of 9,804 hospitalization discharges coded with COPD exacerbation as a primary diagnosis were included; 75.4% of cases were male with a mean age of 74.9±10.5 years and an average length of stay of 6.5±6.1 days. The highest number of admissions (3,644 [37.2%] occurred during winter, followed by autumn with 2,367 (24.1%, spring with 2,347 (23.9%, and summer with 1,446 (14.7%; P<0.001. The maximum, minimum, and mean temperatures were associated similarly with the

  4. Synthesis of Y2O3 Nano-Powder from Yttrium Oxalate under Ambient Temperature

    Institute of Scientific and Technical Information of China (English)

    Li Ling

    2005-01-01

    High purity Y2O3 nano-powders was synthesized directly from solution of industrial YCl3 by method of oxalate precipitation through super-micro-reactors made by complex non-ionic surfactant. The purity and diameter of Y2O3 particles were controlled by such processing parameters as concentration of YCl3 and oxalic acid and complex non-ionic surfactant etc. TEM photomicrographs show that Y2O3 particles are spherical in shape, with an average diameter of less than 30 nm. Test results certify that the purity and particle diameter as well as the dispersion of Y2O3 nano-powder depend on the concentrations of YCl3, oxalic acid and complex non-ionic surfactant. The optimum ranges of the concentrations for YCl3 and complex non-ionic surfactant when the diameter of Y2O3 particles is smaller than 100 nm are 0.43~1.4 mol·L-1 and 0.031~0.112 mol·L-1 respectively, while the mass fraction range of oxalic acid is 10%~18%. The purity of Y2O3 nano-powder tested by ICP-AES analysis is 99.99%.

  5. Ambient temperature desulfurizer of nano-ZnO modified with cerium

    Institute of Scientific and Technical Information of China (English)

    LI Fen; YAN Bo; ZHANG Jie; JIANG An-xi; SHAO Chun-hong; ZHANG Yan-ping

    2008-01-01

    The compound nano-ZnO modified with Ce was prepared by homogeneous precipitation. IR, XRD and dynamic experiments show that the crystal size of nano-ZnO desulfurizer is decreased after being modified with Ce and its desulfurization activities are improved greatly. When calcined at 270 ℃, Ce distributes evenly calcining temperature is 570℃, the crystal CeO2separates out and the amorphous structure of zinc oxide disap-pears, at the same time, the crystal is perfect and its size increases, but the desulfurization activities decrease. The desulfurization product of nano-ZnO modified with Ce was analyzed with XPS. The results show that the ad-sorption compound of HS, S and ZnS exists on the surface of the desulfurizer.

  6. Station for spatially distributed measurements of soil moisture and ambient temperature

    Science.gov (United States)

    Jankovec, Jakub; Šanda, Martin; Haase, Tomáš; Sněhota, Michal; Wild, Jan

    2013-04-01

    Third generation of combined thermal and soil moisture standalone field station coded TMS3 with wireless communication is presented. The device combines three thermometers (MAXIM/DALLAS Semiconductor DS7505U with -55 to +125°C range and 0.0625°C resolution, 0.5°C precision in 0 to +70°C range and 2°C precision out of this range). Soil moisture measurement is performed based on time domain transmission (TDT) principle for the full range of soil moisture with 0.025% resolution within the full possible soil moisture span for the most typical conditions of dry to saturated soils with safe margins to enable measurements in freezing, hot or saline soils. Principal compact version is designed for temperature measurements approximately at heights -10, 0 and +15 cm relative to soil surface when installed vertically and soil moisture measurements between 0 and 12 cm below surface. Set of buriable/subsurface stations each with 2.2 meter extension cord with soil and surface temperature measurement provides possibility to scan vertical soil profile for soil moisture and temperature at desired depths. USB equipped station is designed for streamed direct data acquisition in laboratory use in 1s interval. Station is also equipped with the shock sensor indicating the manipulation. Presented version incorporates life time permanent data storage (0.5 million logs). Current sensor design aims towards improved durability in harsh outdoor environment with reliable functioning in wet conditions withstanding mechanical or electric shock destruction. Insertion into the soil is possible by pressing with the use of a simple plastic cover. Data are retrieved by contact portable pocket collector (second generation) or by RFID wireless communication for hundreds meter distance (third generation) in either star pattern of GSM hub to stations or lined up GSM to station to another station both in comprised data packets. This option will allow online data harvesting and real time process

  7. Effect of season and high ambient temperature on activity levels and patterns of grizzly bears (Ursus arctos.

    Directory of Open Access Journals (Sweden)

    Michelle L McLellan

    Full Text Available Understanding factors that influence daily and annual activity patterns of a species provides insights to challenges facing individuals, particularly when climate shifts, and thus is important in conservation. Using GPS collars with dual-axis motion sensors that recorded the number of switches every 5 minutes we tested the hypotheses: 1. Grizzly bears (Ursus arctos increase daily activity levels and active bout lengths when they forage on berries, the major high-energy food in this ecosystem, and 2. Grizzly bears become less active and more nocturnal when ambient temperature exceeds 20°C. We found support for hypothesis 1 with both male and female bears being active from 0.7 to 2.8 h longer in the berry season than in other seasons. Our prediction under hypothesis 2 was not supported. When bears foraged on berries on a dry, open mountainside, there was no relationship between daily maximum temperature (which varied from 20.4 to 40.1°C and the total amount of time bears were active, and no difference in activity levels during day or night between warm (20.4-27.3°C and hot (27.9-40.1°C days. Our results highlight the strong influence that food acquisition has on activity levels and patterns of grizzly bears and is a challenge to the heat dissipation limitation theory.

  8. Effect of season and high ambient temperature on activity levels and patterns of grizzly bears (Ursus arctos).

    Science.gov (United States)

    McLellan, Michelle L; McLellan, Bruce N

    2015-01-01

    Understanding factors that influence daily and annual activity patterns of a species provides insights to challenges facing individuals, particularly when climate shifts, and thus is important in conservation. Using GPS collars with dual-axis motion sensors that recorded the number of switches every 5 minutes we tested the hypotheses: 1. Grizzly bears (Ursus arctos) increase daily activity levels and active bout lengths when they forage on berries, the major high-energy food in this ecosystem, and 2. Grizzly bears become less active and more nocturnal when ambient temperature exceeds 20°C. We found support for hypothesis 1 with both male and female bears being active from 0.7 to 2.8 h longer in the berry season than in other seasons. Our prediction under hypothesis 2 was not supported. When bears foraged on berries on a dry, open mountainside, there was no relationship between daily maximum temperature (which varied from 20.4 to 40.1°C) and the total amount of time bears were active, and no difference in activity levels during day or night between warm (20.4-27.3°C) and hot (27.9-40.1°C) days. Our results highlight the strong influence that food acquisition has on activity levels and patterns of grizzly bears and is a challenge to the heat dissipation limitation theory.

  9. Effects of ambient air temperature, humidity and rainfall on annual survival of adult little penguins Eudyptula minor in southeastern Australia

    Science.gov (United States)

    Ganendran, L. B.; Sidhu, L. A.; Catchpole, E. A.; Chambers, L. E.; Dann, P.

    2016-08-01

    Seabirds are subject to the influences of local climate variables during periods of land-based activities such as breeding and, for some species, moult; particularly if they undergo a catastrophic moult (complete simultaneous moult) as do penguins. We investigated potential relationships between adult penguin survival and land-based climate variables (ambient air temperature, humidity and rainfall) using 46 years of mark-recapture data of little penguins Eudyptula minor gathered at a breeding colony on Phillip Island in southeastern Australia. Our results showed that adult penguin survival had a stronger association with land-based climate variables during the moult period, when birds were unable to go to sea for up to 3 weeks, than during the breeding period, when birds could sacrifice breeding success in favour of survival. Annual adult survival probability was positively associated with humidity during moult and negatively associated with rainfall during moult. Prolonged heat during breeding and moult had a negative association with annual adult survival. Local climate projections suggest increasing days of high temperatures, fewer days of rainfall which will result in more droughts (and by implication, lower humidity) and more extreme rainfall events. All of these predicted climate changes are expected to have a negative impact on adult penguin survival.

  10. A warmer ambient temperature increases the passage of interleukin-1β into the brains of old rats

    Science.gov (United States)

    Buchanan, Jessica B.; Peloso, Elizabeth; Satinoff, Evelyn

    2008-01-01

    We have demonstrated that after intraperitoneal lipopolysaccharide (LPS) injection, old rats mount fevers similar to those of young rats at an ambient temperature (Ta) of 31°C, but not at 21°C. The same is true for intraperitoneal or intravenous IL-1β administration. The underlying mechanism responsible for blunted fever in old rats may be a deficiency in communication between the periphery and the brain. Possibly, peripheral cytokine actions are altered in old rats, such that the signal that reaches the brain is diminished. Here, we hypothesized that at standard laboratory temperatures, not enough IL-1β is reaching the brain for fever to occur and that a warmer Ta would increase the influx of IL-1β into the brain, enabling old rats to generate fever. Young (3–5 mo) and old (23–29 mo) Long-Evans rats were maintained for 3 days at either Ta 21 or 31°C prior to intravenous injection with radiolabeled IL-1β to measure passage across the blood-brain barrier. Young rats showed similar influx of IL-1β into the brain at the two Tas, but old rats showed significant influx only at the warmer Ta. These data suggest that the lack of fever at a cool Ta may be due to a reduced influx of IL-1β into the brain. PMID:18448612

  11. Analysis of the energetic metabolism in cyclic Bedouin goats (Capra hircus): Nychthemeral and seasonal variations of some haematochemical parameters in relation with body and ambient temperatures.

    Science.gov (United States)

    Malek, Mouna; Amirat, Zaina; Khammar, Farida; Khaldoun, Mounira

    2016-08-01

    Several studies have examined changes in some haematochemical parameters as a function of the different physiological status (cyclic, pregnant and lactating) of goats, but no relevant literature has exhaustively investigated these variations from anestrous to estrous stages in cyclic goats. In this paper, we report nychthemeral and seasonal variations in ambient and body temperatures, and in some haematochemical parameters (glycemia, cholesterolemia, triglyceridemia, creatininemia and uremia) measured during summer, winter and spring, in seven (7) experimental cyclic female Bedouin goats (Capra hircus) living in the Béni-Abbès region (Algerian Sahara desert). Cosinor rhythmometry procedure was used to determine the rhythmic parameters of ambient temperature and haematochemical parameters. To determine the effect of time of day on the rhythmicity of the studied parameters, as well as their seasonality, repeated measure analysis of variance (ANOVA) was applied. The results showed that in spite of the nychthemeral profile presented by the ambient temperature for each season, the body temperature remained in a narrow range, thus indicating a successful thermoregulation. The rhythmometry analysis showed a circadian rhythmicity of ambient temperature and haematochemical parameters with diurnal acrophases. A statistically significant effect of the time of day was shown on all studied haematochemical parameters, except on creatininemia. It was also found that only uremia, cholesterolemia and triglyceridemia followed the seasonal sexual activity of the studied ruminant. This study demonstrated the good physiological adaptation developed by this breed in response to the harsh climatic conditions of its natural environment.

  12. Ambient pH stress inhibits spore germination of Penicillium expansum by impairing protein synthesis and folding: a proteomic-based study.

    Science.gov (United States)

    Li, Boqiang; Lai, Tongfei; Qin, Guozheng; Tian, Shiping

    2010-01-01

    Spore germination is the first step for fungal pathogens to infect host plants. The pH value, as one of the most important environmental parameters, has critical influence on spore germination. In this study, effects of ambient pH on spore germination were determined by culturing spores of Penicillium expansum in medium with pH values at 2.0, 5.0 and 8.0, and involved mechanisms were further investigated through methods of comparative proteomics. The results demonstrated that spore germination of P. expansum was obviously inhibited at pH 2.0 and 8.0. Using quadrupole time-of-flight tandem mass spectrometer, 34 proteins with significant changes in abundance were identified. Among them, 17 proteins were related to protein synthesis and folding, and most of them were down-regulated at pH 2.0 and 8.0. Accordingly, lower content of total soluble proteins and higher ratio of aggregated proteins were observed in spores at pH 2.0 and 8.0. In addition, it was found that ambient pH could affect intracellular pH and ATP level of P. expansum spores. These findings indicated that ambient pH might affect spore germination of P. expansum by changing intracellular pH and regulating protein expression. Further, impairing synthesis and folding of proteins might be one of the main reasons.

  13. Temperature-induced volatility of molecular markers in ambient airborne particulate matter

    Directory of Open Access Journals (Sweden)

    C. R. Ruehl

    2011-01-01

    Full Text Available Molecular markers are organic compounds used to represent known sources of particulate matter (PM in statistical source apportionment studies. The utility of molecular markers depends on, among other things, their ability to represent PM volatility under realistic atmospheric conditions. We measured the particle-phase concentrations and temperature-induced volatility of commonly-used molecular markers in California's heavily polluted San Joaqin Valley. Concentrations of elemental carbon, organic carbon, levoglucosan, and polycyclic aromatic hydrocarbons were not reduced by mild (~10 K heating. In contrast, both hopane/sterane and n-alkane concentrations were reduced, especially during the summer sampling events at the urban site. These results suggest that hopanes and steranes have effective saturation concentrations ~1 μg m−3, and therefore can be considered semi-volatile. The volatility of an individual compound depends both on its inherent properties (primarily vapour pressure and the interactions between itself and any potential absorbing phase. The volatility behavior of n-alkanes during the urban summer is consistent with that predicted for absorption by suberic acid (a C8 diacid using a group contribution modelling method. Observations can also be matched by an absorbent whose composition is based on recently-obtained high-resolution aerosol mass spectrometer factors (approximately 33% "hydrocarbon-like" and 67% oxygenated organic aerosol. The reduced evaporation of the n-alkanes, hopanes, and steranes with mild heating during rural and/or winter experiments could be explained by a more oxygenated absorbing phase along with a non-absorptive partitioning mechanism, such as adsorption to soot. This suggests that the temperature-induced volatility of large hydrocarbons in PM is most important if a relatively non-polar absorbing organic phase exists. While the activity coefficients of most organic

  14. Partial nitrification of non-ammonium-rich wastewater within biofilm filters under ambient temperature.

    Science.gov (United States)

    Wang, Hongyu; He, Jiajie; Yang, Kai

    2010-01-01

    This study evaluated the partial nitrification performances of two biofilm filters over a synthetic non-ammonium-rich wastewater at a 20°C room temperature under both limited DO (∼2.0 mg/L) and unlimited DO (∼4.0 mg/L) conditions. The two filters were each of 80 cm long and used different biofilm carriers: activated carbon and ceramic granule. Results showed that partial nitrification was accomplished for both filters under the limited DO condition. However, the effluent NO(2)-N was higher in the ceramic granule filter than in the activated carbon filter, and was less susceptible to the influent COD/N changes. Further investigation into the water phase COD and NH(4)-N depth profiles and bacteria population within the two filters showed that by putting upper filter layer (upstream) to confront relatively higher influent COD/N ratios, the filtration process naturally put lower filter layers (downstream) relatively more favorable for nitrifying bacteria (ammonia oxidizing bacteria in this study) to prosper, making the filter depth left for nitrification a crucial factor for the effectiveness of nitrification with a filter. The potentially different porous flow velocities of the two filters might be the reason to cause their different partial nitrification performances, with a lower porous flow velocity (the ceramic granule filter) favoring partial nitrification more. In summation, DO, filter depth, and filtration speed should be played together to successfully operate a biofilm filter for partial nitrification.

  15. Differential chromosomal and mitochondrial DNA synthesis in temperature-sensitive mutants of Ustilago maydis

    Energy Technology Data Exchange (ETDEWEB)

    Unrau, P.

    1977-01-01

    The amount and type of residual DNA synthesis was determined in eight temperature-sensitive mutants of the smut fungus Ustilago maydis after incubation at the restrictive temperature (32/sup 0/C) for eight hours. Mutants ts-220, ts-207, ts-432 and ts-346 were found to have an overall reduction in the synthesis of both nuclear and mitochondrial DNA in comparison to the wild-type. In mutants ts-20, tsd 1-1, ts-84 and pol 1-1 nuclear DNA synthesis was depressed relative to mitochondrial synthesis. The DNA-polymerase mutant pol 1-1 had persistent nuclear synthesis at about 50% of the rate of synthesis of mitochondrial DNA and similar behavior was observed in a diploid homozygous strain. Mutant ts-84 had an initial burst of DNA synthesis which was reduced for nuclear but not mitochondrial synthesis after three hours preincubation at 32/sup 0/C. tsd 1-1 and ts-20 had nuclear residual synthesis amounting to about 25% of the relative rate of mitochondrial synthesis which correlates to increasing UV sensitivity of these strains on incubation at 32/sup 0/C. A pol 1-1 ts-84 double mutant had an additive loss of nuclear DNA synthesis which indicates that the steps of replication involved may be sequential.

  16. Association between children's forced vital capacity and long-term exposure to local ambient temperature in China: A national cross-sectional survey.

    Science.gov (United States)

    Li, Qin; Wang, Hai-Jun; Song, Yi; Ma, Jun; Song, Jie-Yun; Guo, Yuming

    2016-07-01

    It is well documented that short-term exposure to extreme ambient temperature is associated with respiratory disorder. However, few studies have assessed the long-term effect of temperature on children's lung function. The present study aimed to investigate the association between long-term exposure to local ambient temperature and children's forced vital capacity (FVC) in China. We analyzed the FVC data of 71,768 children from the 2010 Chinese National Survey on Students' Construction and Health (CHNSCH), and local annual average ambient temperature, relative humidity, air pollutants data from China Meteorological Administration and Ministry of Environment Protection of China. Generalized additive model (GAM) with non-linear function was used to examine the effect of ambient temperature on children's FVC. The results showed that low temperature was significantly associated with decrease of FVC in Chinese children within certain temperature range while adjusting for individual characteristics, socioeconomic conditions, air pollutants and relative humidity. The largest alteration of FVC related to the annual average temperature difference among cities from 20.4°C to 4.5°C was observed, being 242.7ml (95%CI: 220.0, 265.3) decrease in FVC. The similar association was found in both physically active and inactive children, while the largest alteration of FVC related to the temperature difference reached 329.1ml (95%CI: 296.7, 361.6) in physically active children and 290.5ml (95%CI: 255.7, 325.3) in physically inactive ones. Public health policy should be developed for protecting children's respiratory health during growth and development in some areas with cold weather. Key message What is the key question? Few studies have assessed the long-term effect of temperature on children's forced vital capacity (FVC). We analyzed the Chinese national survey data to clarify the association between children's forced vital capacity and long-term exposure to local ambient

  17. Hydration products of lime-metakaolin pastes at ambient temperature with ageing

    Energy Technology Data Exchange (ETDEWEB)

    Gameiro, A., E-mail: agameiro@lnec.pt [National Laboratory of Civil Engineering, Materials Department, Av. do Brasil, 101, 1700 Lisbon (Portugal); Santos Silva, A., E-mail: ssilva@lnec.pt [National Laboratory of Civil Engineering, Materials Department, Av. do Brasil, 101, 1700 Lisbon (Portugal); Veiga, R., E-mail: rveiga@lnec.pt [National Laboratory of Civil Engineering, Buildings Department, Av. do Brasil, 101, 1700 Lisbon (Portugal); Velosa, A., E-mail: avelosa@ua.pt [Department of Civil Engineering, Geobiotec, University of Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal)

    2012-05-10

    Highlights: Black-Right-Pointing-Pointer We study the compounds formed in lime/MK blended pastes and their stability over time. Black-Right-Pointing-Pointer Different mixes of lime/MK pastes show different reaction kinetics during curing time, being the pozzolanic compounds formed directly proportional to the lime by MK replacement. Black-Right-Pointing-Pointer Some pozzolanic products are found to be unstable during the hydration reaction employed in our study. - Abstract: Mortars constituted of lime mixtures with pozzolanic additions have been extensively used in the past for the construction of historic and traditional buildings. This paper presents the results of blended pastes of lime and metakaolin (MK), namely compounds formed and their stability over time. This research is part of an extensive study aiming at the formulation of lime based mortars for restoration purposes. It has been shown for several years that MK has been applied in inorganic binders due to its capacity to react vigorously with calcium hydroxide (CH). In the presence of water originating a series of major hydrated phases, namely tetra calcium aluminate hydrate (C{sub 4}AH{sub 13}), calcium silicates hydrates (CSH) and calcium aluminium silicate hydrates (stratlingite - C{sub 2}ASH{sub 8}). Several blended pastes of lime and MK, with different substitution rates of lime by MK (wt%) were prepared and cured at a temperature of 20 Degree-Sign C and relative humidity RH > 95%. The phase composition of the formed hydrated phases was determined by X-ray diffraction (XRD) and simultaneous thermal analysis (TG-DTA). The obtained results showed that lime/MK pastes compositions displayed different reaction kinetics during curing time, being the pozzolanic products content directly proportional to the substitution rate of lime by MK. Also, a relationship between the increase stratlingite content and the MK substitution rate of lime by MK was found.

  18. A moderate increase in ambient temperature modulates the Atlantic cod (Gadus morhua spleen transcriptome response to intraperitoneal viral mimic injection

    Directory of Open Access Journals (Sweden)

    Hori Tiago S

    2012-08-01

    pIC at 10°C vs. 16°C at 6HPI. These results substantially increase our understanding of the genes and molecular pathways involved in the negative impacts of elevated ambient temperature on fish health, and may also be valuable to our understanding of how accelerated global climate change could impact cold-water marine finfish species.

  19. Mechanical Behavior and Thermal Stability of Acid-Base Phosphate Cements and Composites Fabricated at Ambient Temperature

    Science.gov (United States)

    Colorado Lopera, Henry Alonso

    This dissertation presents the study of the mechanical behavior and thermal stability of acid-base phosphate cements (PCs) and composites fabricated at ambient temperature. These materials are also known as chemically bonded phosphate ceramics (CBPCs). Among other advantages of using PCs when compared with traditional cements are the better mechanical properties (compressive and flexural strength), lower density, ultra-fast (controllable) setting time, controllable pH, and an environmentally benign process. Several PCs based on wollastonite and calcium and alumino phosphates after thermal exposure up to 1000°C have been investigated. First, the thermo-mechanical and chemical stability of wollastonite-based PC (Wo-PC) exposed to temperatures up to 1000°C in air environment were studied. The effects of processing conditions on the curing and shrinkage of the wollastonite-based PC were studied. The chemical reactions and phase transformations during the fabrication and during the thermal exposure are analyzed in detail using scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA Then, the thermo-mechanical and chemical stability of glass, carbon and basalt fiber reinforced Wo-PC composites, were studied using SEM, XRD, TGA. The flexural strength and Weibull statistics were analyzed. A significant strength degradation in the composites were found after the thermal exposure at elevated temperatures due to the interdifusion and chemical reactions across the fibers and the matrix at temperatures over 600°C. To overcome this barrier, we have developed a new PC based on calcium and alumino-phosphates (Ca-Al PCs). The Ca-Al PCs were studied in detail using SEM, XRD, TGA, curing, shrinkage, Weibull statistics, and compression tests. Our study has confirmed that this new composite material is chemically and mechanically stable at temperatures up to 1000°C. Moreover, the compression strength increases after exposure to 1000

  20. Novel Cubic Magnetite Nanoparticle Synthesis Using Room Temperature Ionic Liquid

    Directory of Open Access Journals (Sweden)

    M. Sundrarajan

    2012-01-01

    Full Text Available Room Temperature Ionic liquids are relatively more useful in the synthesis of inorganic nanostructured materials because of their unique properties. To synthesize the iron oxide nanoparticle in simple precipitation method, a novel ionic liquid was used as the greener medium and stabilizing agent namely “1-n-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][TfO]”. The crystallinity, chemical structure, morphology and magnetic properties of the synthesized magnetite nanoparticles have been characterized by using X-ray diffraction (XRD, Fourier Transform Infrared (FT-IR, Scanning electron microscopy (SEM, Atomic force microscopy(AFM, Transmission electron microscopy (TEM and Vibrating sample magnetometer (VSM studies. The XRD study is divulge that the synthesized magnetite nanoparticles have inverse spinel face centered cubic structure. The FT-IR vibration peaks show the formation of Fe3O4 nanoparticles, where the vibration peak for Fe-O is deliberately presence at 584 cm-1. The average particle size of the synthesized nanoparticles is found to be 35 nm. Homogeneously dispersed cubic shape with superstructure is found through SEM, AFM and TEM examination studies. The synthesized iron oxide nanoparticles have a high saturation magnetization value of 25 emu/g, which is very much useful for biomedical applications.

  1. Synthesis of titanium carbide from wood by self-propagating high temperature synthesis

    Directory of Open Access Journals (Sweden)

    Sutham Niyomwas

    2010-05-01

    Full Text Available Titanium carbide (TiC particles were obtained in situ by a self-propagating high temperature synthesis (SHS of wooddust with TiO2 and Mg. The reaction was carried out in a SHS reactor under static argon gas at the pressure of 0.5 MPa. Thestandard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. Theeffects of increasing Mg mole ratio to the precursor mixture of TiO2 and wood dusts were investigated. XRD and SEManalyses indicate a complete reaction of the precursors to yield TiC-MgO as a product composite. The synthesized compositeswere leached with 0.1M HCl acid solution to obtain TiC particles as final products.

  2. Vaulted trans-bis(salicylaldiminato)platinum(II) crystals: heat-resistant, chromatically sensitive platforms for solid-state phosphorescence at ambient temperature.

    Science.gov (United States)

    Komiya, Naruyoshi; Okada, Minoru; Fukumoto, Kanako; Kaneta, Kenji; Yoshida, Atsushi; Naota, Takeshi

    2013-04-08

    The synthesis, structure, and solid-state emission of vaulted trans-bis(salicylaldiminato)platinum(II) complexes are described. A series of polymethylene (1: n=8; 2: n=9; 3: n=10; 4: n=11; 5: n=12; 6: n=13) and polyoxyethylene (7: m=2; 8: m=3; 9: m=4) vaulted complexes (R=H (a), 3-MeO (b), 4-MeO (c), 5-MeO (d), 6-MeO (e), 4-CF3O (f), 5-CF3O (g)) was prepared by treating [PtCl2(CH3CN)2] with the corresponding N,N'-bis(salicylidene)-1,ω-alkanediamines. The trans coordination, vaulted structures, and the crystal packing of 1-9 have been unequivocally established from X-ray diffraction studies. Unpredictable, structure-dependent phosphorescent emission has been observed for crystals of the complexes under UV excitation at ambient temperature, whereas these complexes are entirely nonemissive in the solution state under the same conditions. The long-linked complex crystals 4-6, 8, and 9 exhibit intense emission (Φ77K =0.22-0.88) at 77 K, whereas short-linked complexes 1-3 and 7 are non- or slightly emissive at the same temperature (Φ77K solid-state emission over the range of 98 nm can be performed simply by introducing MeO groups at different positions on the aromatic rings. Orange, yellow-green, red, and yellow emissions are observed in the glass and crystalline state upon 3-, 4-, 5-, and 6-MeO substitution, respectively, whereas those with CF3 O substituents have orange emission, irrespective of the substitution position. DFT calculations (B3LYP/6-31G*, LanL2DZ) showed that such chromatic variation is ascribed to the position-specific influence of the substituents on the highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) levels of the trans-bis(salicylaldiminato)platinum(II) platform. The solid-state emission and its heat resistance have been discussed on the basis of X-ray diffraction studies. The planarity of the trans-coordination sites is strongly correlated to the solid-state emission intensities of crystals 1-9 at lower

  3. Optimal foraging behavior and the thermal neutral zone of Peromyscus leucopus during winter: A test using natural and controlled ambient temperatures.

    Science.gov (United States)

    St Juliana, Justin R; Mitchell, William A

    2016-02-01

    Endotherms foraging at temperatures outside of their thermal neutral zone (TNZ) pay an increased energetic cost. We asked if thermally-induced changes in foraging costs influence quitting harvest rate (QHR) of mice. We predicted that mice foraging during the winter would have a higher QHR in more costly colder conditions. We conducted our study with wild caught Peromyscus leucopus in an enclosure located in West Terre Haute, Indiana. We assayed changes in QHR using the forager's giving up density (GUD), which is the amount of uneaten seeds reaming in a tray after foraging activity. Each night from January 12th to March 13th, we assigned 4 trays as "cold trays" (at ambient temperature), and 4 trays as "hot trays" (trays with a ceramic heat element that increased the temperatures of feeding trays ca. 10-15°C). GUDs (and therfore QHRs) increased as a function of decreasing ambient temperature. Furthermore there was an interaction between tray temperature and ambient temperature; namely, on cool nights mice had lower GUDs in the "hot trays", but on warm nights mice had lower GUDs in the "cold trays". The TNZ for P. leucopus actively foraging during winter may be closer to the environmental average temperature than typically measured in the laboratory. Overall, these results support the idea that QHR is related to an animal's foraging in thermally challenged conditions. We present a unique way of measuring an animal's TNZ in the field using behavioral indicators.

  4. The influence of the starvation-predation trade-off on the relationship between ambient temperature and body size among endotherms

    NARCIS (Netherlands)

    McNamara, John M.; Higginson, Andrew D.; Verhulst, Simon

    2016-01-01

    Aim: The tendency for animals at higher latitudes to be larger (Bergmann's rule) is generally explained by recourse to latitudinal effects on ambient temperature and the food supply, but these receive only mixed support and do not explain observations of the inverse to Bergmann's rule. Our aim was t

  5. Ambient-temperature trap/release of arsenic by dielectric barrier discharge and its application to ultratrace arsenic determination in surface water followed by atomic fluorescence spectrometry

    Science.gov (United States)

    A novel dielectric barrier discharge reactor (DBDR) was utilized to trap/release arsenic coupled to hydride generation atomic fluorescence spectrometry (HGAFS). On the DBD principle, the precise and accurate control of trap/release procedures was fulfilled at ambient temperature, and an analytical m...

  6. Observation of immobile regions in natural rubber at ambient temperature by solid-state C-13 CP/MAS NMR spectroscopy

    DEFF Research Database (Denmark)

    Larsen, F.H.; Rasmussen, T.; Pedersen, Walther Batsberg

    1999-01-01

    Employing C-13 CP/MAS NMR spectroscopy, the existence of immobile regions in natural rubber (cis-1,4-polyisoprene) corresponding to a few percent of the monomer units has been detected at ambient temperature. For synthetic rubbers no immobile regions have been detected at all. Applying different...

  7. Effects of ambient temperature and oxygen concentration on diesel spray combustion using a single-nozzle injector in a constant volume combustion chamber

    KAUST Repository

    Jing, Wei

    2013-09-02

    This work investigates the effects of ambient conditions on diesel spray combustion in an optically accessible, constant volume chamber using a single-nozzle fuel injector. The ambient O2 concentration was varied between five discrete values from 10% to 21% and three different ambient temperatures (800 K, 1000 K, and 1200 K). These conditions simulate different exhaust gas recirculation (EGR) levels and ambient temperatures in diesel engines. Both conventional diesel combustion and low temperature combustion (LTC) modes were observed under these conditions. A transient analysis and a quasi-steady state analysis are employed in this article. The transient analysis focuses on the flame development from beginning to the end, illustrating how the flame structure changes during this process; the quasi-steady state analysis focuses on the stable flame structure. The transient analysis was conducted using high-speed imaging of both OH* chemiluminescence and natural luminosity (NL). In addition, three different images were acquired using an ICCD camera, corresponding to OH* chemiluminescence, narrow-band flame emission at 430 nm (Band A) and at 470 nm (Band B), and were used to investigate the quasi-steady state combustion process. From the transient analysis, it was found that the NL signal becomes stronger and confined to narrow regions when the temperature and O2 concentration increase during the development of flame. The OH* intensity is much lower for the 10% ambient O2 and 800 K conditions compared to the higher temperatures and O2 levels. This implies the occurrence of LTC under these conditions. Results from the quasi-steady combustion stage indicate that high-temperature reactions effectively oxidize the soot in the downstream locations where only OH* signal is observed. In addition, an area was calculated for each spectral region, and results show that the area of Band A and Band B emissions in these images is larger than the area of OH* emissions at the lower O2

  8. Performance of a completely autotrophic nitrogen removal over nitrite process for treating wastewater with different substrates at ambient temperature

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan Chang; Dong Li; Yuhai Liang; Zhuo Yang; Shaoming Cui; Tao Liu; Huiping Zeng

    2013-01-01

    The stability and parameters of a bio-ceramic filter for completely autotrophic nitrogen removal were investigated.The completely autotrophic nitrogen removal over nitrite (CANON) reactor was fed with different concentrations of ammonia (400,300,and 200 mg N/L) but constant influent ammonia load.The results showed that the CANON system can achieve good treatment performance at ambient temperature (15-23℃).The average removal rate and removal loading of NH4 +-N and TN was 83.90%,1.26 kg N/(m3.day),and 70.14%,1.09 kg N/(m3.day),respectively.Among the influencing factors like pH,dissolved oxygen and alkalinity,it was indicated that the pH was the key parameter of the performance of the CANON system.Observing the variation of pH would contribute to better control of the CANON system in an intuitive and fast way.Denaturing gradient gel electrophoresis analysis of microorganisms further revealed that there were some significant changes in the community structure of ammonium oxidizing bacteria,which had low diversity in different stages,while the species of anaerobic ammonium oxidizing (anammox) bacteria were fewer and the community composition was relatively stable.These observations showed that anaerobic ammonia oxidation was more stable than the aerobic ammonia oxidation,which could explain that why the CANON system maintained a good removal efficiency under the changing substrate conditions.

  9. In Situ Ambient Pressure X-ray Photoelectron Spectroscopy of Cobalt Perovskite Surfaces under Cathodic Polarization at High Temperatures

    KAUST Repository

    Crumlin, Ethan J.

    2013-08-08

    Heterostructured oxide interfaces have demonstrated enhanced oxygen reduction reaction rates at elevated temperatures (∼500-800 C); however, the physical origin underlying this enhancement is not well understood. By using synchrotron-based in situ ambient pressure X-ray photoelectron spectroscopy (APXPS), we focus on understanding the surface electronic structure, elemental composition, and chemical nature of epitaxial La0.8Sr 0.2CoO3-δ (LSC113), (La 0.5Sr0.5)2CoO4±δ (LSC214), and LSC214-decorated LSC113 (LSC 113/214) thin films as a function of applied electrical potentials (0 to -800 mV) at 520 C and p(O2) of 1 × 10-3 atm. Shifts in the top of the valence band binding energy and changes in the Sr 3d and O 1s spectral components under applied bias reveal key differences among the film chemistries, most notably in the degree of Sr segregation to the surface and quantity of active oxygen sites in the perovskite termination layer. These differences help to identify important factors governing the enhanced activity of oxygen electrocatalysis observed for the LSC113/214 heterostructured surface. © 2013 American Chemical Society.

  10. Lithium plating in lithium-ion batteries at sub-ambient temperatures investigated by in situ neutron diffraction

    Science.gov (United States)

    Zinth, Veronika; von Lüders, Christian; Hofmann, Michael; Hattendorff, Johannes; Buchberger, Irmgard; Erhard, Simon; Rebelo-Kornmeier, Joana; Jossen, Andreas; Gilles, Ralph

    2014-12-01

    Lithium plating in commercial LiNi1/3Mn1/3Co1/3O2/graphite cells at sub-ambient temperatures is studied by neutron diffraction at Stress-Spec, MLZ. Li plating uses part of the active lithium in the cell and competes with the intercalation of lithium into graphite. As a result, the degree of graphite lithiation during and after charge is lower. Comparison of graphite lithiation after a C/5 charging cycle fast enough to expect a considerable amount of Li plating with a much slower C/30 reference cycle reveals a lower degree of graphite lithiation in the first case; neutron diffraction shows less LiC6 and more LiC12 is present. If the cell is subjected to a 20 h rest period after charge, a gradual transformation of remaining LiC12 to LiC6 can be observed, indicating Li diffusion into the graphite. During the rest period after the C/5 charging cycle, the degree of graphite lithiation can be estimated to increase by 17%, indicating at least 17% of the active lithium is plated. Data collected during discharge immediately after C/5 charging give further evidence of the presence and amount of metallic lithium: in this case 19% of discharge capacity originates from the oxidation of metallic lithium. Also, lithium oxidation can be directly related to the high voltage plateau observed during discharge in case of lithium plating.

  11. Lithium-functionalized metal-organic frameworks that show >10 wt% H2 uptake at ambient temperature.

    Science.gov (United States)

    Han, Sang Soo; Jung, Dong Hyun; Choi, Seung-Hoon; Heo, Jiyoung

    2013-08-26

    We have used grand canonical Monte Carlo simulations with a first-principles-based force field to show that metal-organic frameworks (MOFs) with Li functional groups (i.e. C-Li bonds) allow for exceptional H2 uptake at ambient temperature. For example, at 298 K and 100 bar, IRMOF-1-4Li shows a total H2 uptake of 5.54 wt% and MOF-200-27Li exhibits a total H2 uptake of 10.30 wt%, which are much higher than the corresponding values with pristine MOFs. Li-functionalized MOF-200 (MOF-200-27Li) shows 11.84 wt% H2 binding at 243 K and 100 bar. These hydrogen-storage capacities exceed the 2015 DOE target of 5.5 wt% H2. Moreover, the incorporation of Li functional groups into MOFs provides more benefits, such as higher delivery amount, for H2 uptake than previously reported Li-doped MOFs.

  12. Efficient production of optically pure L-lactic acid from food waste at ambient temperature by regulating key enzyme activity.

    Science.gov (United States)

    Li, Xiang; Chen, Yinguang; Zhao, Shu; Chen, Hong; Zheng, Xiong; Luo, Jinyang; Liu, Yanan

    2015-03-01

    Bio-production of optically pure L-lactic acid from food waste has attracted much interest as it can treat organic wastes with simultaneous recovery of valuable by-products. However, the yield of L-lactic acid was very low and no optically pure L-lactic acid was produced in the literature due to (1) the lower activity of enzymes involved in hydrolysis and L-lactic acid generation, and (2) the participation of other enzymes related to D-lactic acid and acetic and propionic acids production. In this paper, a new strategy was reported for effective production of optically pure L-lactic acid from food waste at ambient temperature, i.e. via regulating key enzyme activity by sewage sludge supplement and intermittent alkaline fermentation. It was found that not only optically pure L-lactic acid was produced, but the yield was enhanced by 2.89-fold. The mechanism study showed that the activities of enzymes relevant to food waste hydrolysis and lactic acid production were enhanced, and the key enzymes related to volatile fatty acids and D-lactic acid generations were severally decreased or inhibited. Also, the microbes responsible for L-lactic acid production were selectively proliferated. Finally, the pilot-scale continuous experiment was conducted to testify the feasibility of this new technique.

  13. Self-sustained high-temperature reactions: initiation, propagation and synthesis

    NARCIS (Netherlands)

    Martinez Pacheco, M.

    2007-01-01

    Self-Propagating High-Temperature Synthesis (SHS), also called combustion synthesis is an exothermic and self-sustained reaction between the constituents, which has assumed significance for the production of ceramics and ceramic-metallic materials (cermets), because it is a very rapid processing tec

  14. Vitamin E and organic selenium enhances the antioxidative status and quality of chicken semen under high ambient temperature.

    Science.gov (United States)

    Ebeid, T A

    2012-01-01

    1. The effects of supplemental dietary vitamin E and organic selenium (Se), and their combination, on improving semen quality characteristics and antioxidative status were investigated in cockerels exposed to high ambient temperature. 2. A total of 36 Egyptian local cross males, 40 weeks old, were housed individually in cages in an open-sided building (average daily temperature ranged from 33 to 36°C and relative humidity from 60 to 70%). Birds were divided randomly into 4 experimental treatments (n=9 each): (1) control (basal diet without any supplementation with vitamin E or Se); (2) vitamin E (basal diet +200 mg α-tocopherol acetate/kg diet); (3) Se (basal diet +0.3 mg organic Se/kg diet); and (4) vitamin E+Se (basal diet +200 mg α-tocopherol acetate/kg diet +0.3 mg organic Se/kg diet). 3. Under heat stress conditions, inclusion of vitamin E and/or organic Se in the diets enhanced the semen quality traits, including the spermatozoa count and motility, and reduced the percentage of dead spermatozoa. 4. A combination of 200 mg/kg vitamin E with 0.3 mg/kg organic Se reduced the thiobarbituric acid reactive substance concentration in seminal plasma samples to about 28% of the controls; and also enhanced the seminal plasma glutathione peroxidase activity by two-fold compared with controls. 5. It was concluded that dietary vitamin E in combination with organic Se has a synergistic effect in minimising lipid peroxidation and improving the antioxidative status in seminal plasma of the domestic fowl, which probably translated into enhanced spermatozoa count, motility and reduced percentage of dead spermatozoa under heat stress conditions.

  15. Physiological Effects of Ergot Alkaloid and Indole-Diterpene Consumption on Sheep under Hot and Thermoneutral Ambient Temperature Conditions.

    Science.gov (United States)

    Henry, Michelle L E; Kemp, Stuart; Dunshea, Frank R; Leury, Brian J

    2016-06-02

    A controlled feeding study was undertaken to determine the physiological and production effects of consuming perennial ryegrass alkaloids (fed via seed) under extreme heat in sheep. Twenty-four Merino ewe weaners (6 months; initial BW 30.8 ± 1.0 kg) were selected and the treatment period lasted 21 days following a 14 day acclimatisation period. Two levels of two factors were used. The first factor was alkaloid, fed at a nil (NilAlk) or moderate level (Alk; 80 μg/kg LW ergovaline and 20.5 μg/kg·LW lolitrem B). The second factor was ambient temperature applied at two levels; thermoneutral (TN; constant 21-22 °C) or heat (Heat; 9:00 AM-5:00 PM at 38 °C; 5:00 PM-9:00 AM at 21-22 °C), resulting in four treatments, NilAlk TN, NilAlk Heat, Alk TN and Alk Heat. Alkaloid consumption reduced dry matter intake ( p = 0.008), and tended to reduce liveweight ( p = 0.07). Rectal temperature and respiration rate were increased by both alkaloid and heat ( p < 0.05 for all). Respiration rate increased to severe levels when alkaloid and heat were combined, indicating the short term effects which may be occurring in perennial ryegrass toxicosis (PRGT) areas during severe weather conditions, a novel finding. When alkaloid ingestion and heat were administered separately, similar physiological responses occurred, indicating alkaloid ingestion causes a similar heat stress response to 38 °C heat.

  16. Physiological Effects of Ergot Alkaloid and Indole-Diterpene Consumption on Sheep under Hot and Thermoneutral Ambient Temperature Conditions

    Directory of Open Access Journals (Sweden)

    Michelle L. E. Henry

    2016-06-01

    Full Text Available A controlled feeding study was undertaken to determine the physiological and production effects of consuming perennial ryegrass alkaloids (fed via seed under extreme heat in sheep. Twenty-four Merino ewe weaners (6 months; initial BW 30.8 ± 1.0 kg were selected and the treatment period lasted 21 days following a 14 day acclimatisation period. Two levels of two factors were used. The first factor was alkaloid, fed at a nil (NilAlk or moderate level (Alk; 80 μg/kg LW ergovaline and 20.5 μg/kg·LW lolitrem B. The second factor was ambient temperature applied at two levels; thermoneutral (TN; constant 21–22 °C or heat (Heat; 9:00 AM–5:00 PM at 38 °C; 5:00 PM–9:00 AM at 21–22 °C, resulting in four treatments, NilAlk TN, NilAlk Heat, Alk TN and Alk Heat. Alkaloid consumption reduced dry matter intake ( p = 0.008, and tended to reduce liveweight ( p = 0.07. Rectal temperature and respiration rate were increased by both alkaloid and heat ( p < 0.05 for all. Respiration rate increased to severe levels when alkaloid and heat were combined, indicating the short term effects which may be occurring in perennial ryegrass toxicosis (PRGT areas during severe weather conditions, a novel finding. When alkaloid ingestion and heat were administered separately, similar physiological responses occurred, indicating alkaloid ingestion causes a similar heat stress response to 38 °C heat.

  17. Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City

    Science.gov (United States)

    Ríos, B.; Torres-Jardón, R.; Ramírez-Arriaga, E.; Martínez-Bernal, A.; Rosas, I.

    2016-05-01

    Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized

  18. Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City.

    Science.gov (United States)

    Ríos, B; Torres-Jardón, R; Ramírez-Arriaga, E; Martínez-Bernal, A; Rosas, I

    2016-05-01

    Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized

  19. Method for the rapid synthesis of large quantities of metal oxide nanowires at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sunkara, Mahendra Kumar (Louisville, KY); Vaddiraju, Sreeram (Mountain View, CA); Mozetic, Miran (Ljubljan, SI); Cvelbar, Uros (Idrija, SI)

    2009-09-22

    A process for the rapid synthesis of metal oxide nanoparticles at low temperatures and methods which facilitate the fabrication of long metal oxide nanowires. The method is based on treatment of metals with oxygen plasma. Using oxygen plasma at low temperatures allows for rapid growth unlike other synthesis methods where nanomaterials take a long time to grow. Density of neutral oxygen atoms in plasma is a controlling factor for the yield of nanowires. The oxygen atom density window differs for different materials. By selecting the optimal oxygen atom density for various materials the yield can be maximized for nanowire synthesis of the metal.

  20. Correlation of rectal temperature and peripheral temperature from implantable radio-frequency microchips in Holstein steers challenged with lipopolysaccharide under thermoneutral and high ambient temperatures.

    Science.gov (United States)

    Reid, E D; Fried, K; Velasco, J M; Dahl, G E

    2012-12-01

    Early detection of disease can speed treatment, slow spread of disease in a herd, and improve health status of animals. Immune stimulation increases rectal temperature (RT). Injectable radio-frequency implants (RFI) can provide temperature at the site of implantation. The fidelity of peripheral site temperature, determined by RFI, relative to RT is unknown in cattle. We hypothesized that during lipopolysaccharide (LPS) challenge, temperature at 3 peripheral sites would be similar to RT in steers (n = 4; BW 77 ± 2.1 kg). The 3 sites were 1) subcutaneous (SC) at the base of the ear (ET); 2) SC posterior to the poll (PT); and 3) SC beneath the umbilical fold (UT). Steers were housed in controlled temperature (CT) rooms (between 18 and 21°C; n = 2/room). Rectal temperature, ET, PT, and UT were recorded every 8 h daily. On d 7, 21, 22, 36, and 37, RT and RFI were taken every 5 min for 6 h, every 15 min for 3 h, and every 30 min for 15 h. To test RFI during a simulated immune challenge, LPS (E. coli 055:B5) was injected intravenously (i.v.) at 1000 h on d 22 and 37. Basal temperatures (°C) were RT (38.7 ± 0.20), ET (37.1 ± 0.86), PT (36.7 ± 0.57), and UT (36.3 ± 0.97). Rectal temperature increased to 39.9 ± 0.30°C after LPS, but ET, PT, and UT decreased. Heat stress also increases RT, which makes it difficult to identify sick animals using RT. The second hypothesis tested was that ET positively correlates to RT and negatively correlates to RT during LPS under heat stress. Four steers (127 ± 7.3 kg) were housed in CT chambers (n = 2/chamber), implanted with a RFI, and allowed 2 wk to acclimate. One chamber remained at 20°C, the other was increased to 34°C starting at 0800 h for a period of 48 h. The LPS was administered i.v. to all steers at 1000 h on d 2. After a 2-wk recovery at 20°C, the temperature was increased in the other chamber, resulting in a crossover design with each steer serving as its own control. Pearson's correlation coefficients for ET and

  1. Disturbances in pro-oxidant-antioxidant balance after passive body overheating and after exercise in elevated ambient temperatures in athletes and untrained men.

    Directory of Open Access Journals (Sweden)

    Wanda Pilch

    Full Text Available The aim of the study was to investigate pro-oxidant-antioxidant balance in two series of examinations with two types of stressors (exogenous heat and the combined exogenous and endogenous heat in trained and untrained men. The exogenous stressor was provided by Finnish sauna session, whereas the combined stressor was represented by the exercise in elevated ambient temperature. The men from the two groups performed the physical exercise on a cycle ergometer with the load of 53 ± 2% maximal oxygen uptake at the temperature of 33 ± 1 °C and relative humidity of 70% until their rectal temperature rose by 1.2 °C. After a month from completion of the exercise test the subjects participated in a sauna bathing session with the temperature of 96 ± 2 °C, and relative humidity of 16 ± 5%. 15-minutes heating and 2-minute cool-down in a shower with the temperature of 20 °C was repeated until rectal temperature rose by 1.2 °C compared to the initial value. During both series of tests rectal temperature was measured at 5-minute intervals. Before both series of tests and after them body mass was measured and blood samples were taken for biochemical tests. Serum total protein, serum concentration of lipid peroxidation products and serum antioxidants were determined. The athletes were characterized by higher level of antioxidant status and lower concentration of lipid peroxidation products. Physical exercise at elevated ambient temperature caused lower changes in oxidative stress indices compared to sauna bathing. Sauna induced a shift in pro-oxidant-antioxidant balance towards oxidation, which was observed less intensively in the athletes compared to the untrained men. This leads to the conclusion that physical exercise increases tolerance to elevated ambient temperature and oxidative stress.

  2. Variability of Battery Wear in Light Duty Plug-In Electric Vehicles Subject to Ambient Temperature, Battery Size, and Consumer Usage: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wood, E.; Neubauer, J.; Brooker, A. D.; Gonder, J.; Smith, K. A.

    2012-08-01

    Battery wear in plug-in electric vehicles (PEVs) is a complex function of ambient temperature, battery size, and disparate usage. Simulations capturing varying ambient temperature profiles, battery sizes, and driving patterns are of great value to battery and vehicle manufacturers. A predictive battery wear model developed by the National Renewable Energy Laboratory captures the effects of multiple cycling and storage conditions in a representative lithium chemistry. The sensitivity of battery wear rates to ambient conditions, maximum allowable depth-of-discharge, and vehicle miles travelled is explored for two midsize vehicles: a battery electric vehicle (BEV) with a nominal range of 75 mi (121 km) and a plug-in hybrid electric vehicle (PHEV) with a nominal charge-depleting range of 40 mi (64 km). Driving distance distributions represent the variability of vehicle use, both vehicle-to-vehicle and day-to-day. Battery wear over an 8-year period was dominated by ambient conditions for the BEV with capacity fade ranging from 19% to 32% while the PHEV was most sensitive to maximum allowable depth-of-discharge with capacity fade ranging from 16% to 24%. The BEV and PHEV were comparable in terms of petroleum displacement potential after 8 years of service, due to the BEV?s limited utility for accomplishing long trips.

  3. Response of the modern lactating sow and progeny to source and level of supplemental dietary fat during high ambient temperatures.

    Science.gov (United States)

    Rosero, D S; van Heugten, E; Odle, J; Arellano, C; Boyd, R D

    2012-08-01

    The objective of this study was to determine the response to increments of 2 sources of dietary fat on lactating sow and progeny performance during high ambient temperatures. Data were collected from 391 sows (PIC Camborough) from June to September in a 2,600-sow commercial unit in Oklahoma. Sows were randomly assigned to a 2 × 3 factorial arrangement of treatments and a control diet. Factors included 1) fat sources, animal-vegetable blend (A-V) and choice white grease (CWG), and 2) fat levels (2%, 4%, and 6%). The A-V blend contained 14.5% FFA with an iodine value of 89, peroxide value of 4.2 mEq/kg, and anisidine value of 23, whereas CWG contained 3.7% FFA with an iodine value of 62, peroxide value of 9.8 mEq/kg, and anisidine value of 5. Diets were corn-soybean meal based, with 8.0% distillers dried grains with solubles and 6.0% wheat middlings, and contained 3.56-g standardized ileal digestible Lys/Mcal ME. Sows were balanced by parity, with 192 and 199 sows representing parity 1 and parity 3 to 5, respectively. Feed refusal increased linearly (P feed and energy intake increased linearly (P Sows fed CWG diets had reduced (linear, P sow and litter gain relative to feed intake) compared with the G:F of sows fed the control diet or the diets containing the A-V blend (0.50, 0.43, and 0.44, respectively; P feed efficiency than CWG. Subsequent litter size and reproductive performance was improved by inclusion of both sources of fat in diets fed to lactating sows.

  4. Degradation of phenol in an upflow anaerobic sludge blanket(UASB) reactor at ambient temperatureKE

    Institute of Scientific and Technical Information of China (English)

    KE Shui-zhou1; SHI Zhou; ZHANG Tong; Herbert H. P. FANG

    2004-01-01

    A synthetic wastewater containing phenol as sole substrate was treated in a 2.8 L upflow anaerobic sludge blanket(UASB) reactor at ambient temperature. The operation conditions and phenol removal efficiency were discussed, microbial population in the UASB sludge was identified based on DNA cloning, and pathway of anaerobic phenol degradation was proposed. Phenol in wastewater was degraded in an UASB reactor at loading rate up to 18 gCOD/(L·d), With a 1:1 recycle ratio, at 26(1℃, pH 7.0-7.5. An UASB reactor was able to remove 99% of phenol up to 1226 mg/L in wastewater with 24 h of hydraulic retention time(HRT). For HRT below 24 h, phenol degradation efficiency decreased with HRT, from 95.4% at 16 h to 93.8% at 12 h. It further deteriorated to 88.5% when HRT reached 8 h. When the concentration of influent phenol of the reactor was 1260 mg/L(corresponding COD 3000 mg/L), with the HRT decreasing(from 40 h to 4 h, corresponding COD loading increasing), the biomass yields tended to increase from 0.265 to 3.08 g/(L·d). While at 12 h of HRT, the biomass yield was lower. When HRT was 12 h, the methane yield was 0.308 L/(gCOD removed), which was the highest. Throughout the study, phenol was the sole organic substrate. The effluent contained only residual phenol without any detectable intermediates, such as benzoate, 4-hydrobenzoate or volatile fatty acids(VFAs). Based on DNA cloning analysis, the sludge was composed of five groups of microorganisms. Desulfotomaculum and Clostridium were likely responsible for the conversion of phenol to benzoate, which was further degraded by Syntrophus to acetate and H2/CO2. Methanogens lastly converted acetate and H2/CO2 to methane. The role of epsilon-Proteobacteria was, however, unsure.

  5. Ambient and elevated temperature fracture and cyclic-fatigue properties in a series of Al-containing silicon carbides

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Rong [Univ. of California, Berkeley, CA (United States)

    2004-01-01

    A series of in situ toughened, Al, B and C containing, silicon carbide ceramics (ABC-SiC) has been examined with Al contents varying from 3 to 7 wt%. With increasing Al additions, the grain morphology in the as-processed microstructures varied from elongated to bimodal to equiaxed, with a change in the nature of the grain-boundary film from amorphous to partially crystalline to fully crystalline. Fracture toughness and cyclic fatigue tests on these microstructures revealed that although the 7 wt.% Al containing material (7ABC) was extremely brittle, the 3 and particularly 5 wt.% Al materials (3ABC and 5ABC, respectively) displayed excellent crack-growth resistance at both ambient (25°C) and elevated (1300 C) temperatures. Indeed, no evidence of creep damage, in the form of grain-boundary cavitation, was seen at temperatures at 1300°C or below. The enhanced toughness of the higher Al-containing materials was associated with extensive crack bridging from both interlocking grains (in 3ABC) and uncracked ligaments (in 5ABC); in contrast, the 7ABC SiC showed no such bridging, concomitant with a marked reduction in the volume fraction of elongated grains. Mechanistically, cyclic fatigue-crack growth in 3ABC and 5ABC SiC involved the progressive degradation of such bridging ligaments in the crack wake, with the difference in the degree of elastic vs. frictional bridging affecting the slope, i.e., Paris law exponent, of the crack-growth curve. In addition an investigation of fracture resistance in non-transforming ceramics toughened by grain bridging mechanism is presented using linear elastic fracture mechanics (LEFM). Linear superposition theorems are used for the superposition of crack opening displacements, as well as stress intensity factors, resulting from the external tractions and the internal compressive bridging stresses. Specifically weight functions are used to relate the CODs, stress intensity factors, and tractions and the bridging stress. Expressions are

  6. Activity, sleep and ambient light have a different impact on circadian blood pressure, heart rate and body temperature rhythms.

    Science.gov (United States)

    Gubin, D G; Weinert, D; Rybina, S V; Danilova, L A; Solovieva, S V; Durov, A M; Prokopiev, N Y; Ushakov, P A

    2017-02-16

    The aim of the present study was to investigate the impact of endogenous and exogenous factors for the expression of the daily rhythms of body temperature (BT), blood pressure (BP) and heart rate (HR). One hundred and seventy-three young adults (YA), 17-24 years old (y.o.), of both genders were studied under a modified constant-routine (CR) protocol for 26 h. Participants were assigned randomly to groups with different lighting regimens: CR-LD, n = 77, lights (>400 l×) on from 09:00 to 17:00 h and off (400 l×) during the whole experimental session; CR-DD, n = 15, constant dim light (measured every 2 h. For comparison, the results of the former studies performed under conditions of regular life with an activity period from 07:00 to 23:00 h and sleep from 23:00 till 07:00 h (Control) were reanalyzed. Seven-day Ambulatory Blood Pressure Monitoring (ABPM) records from 27 YA (16-38 y.o.) and BT self-measurement data from 70 YA (17-30 y.o.) taken on ≥ 3 successive days at 08:00, 11:00, 14:00, 17:00, 20:00, 23:00 and 03:00 were available. The obtained daily patterns were different between Control and CR-DD groups, due to effects of activity, sleep and light. The comparison of Control and CR-LD groups allowed the effects of sleep and activity to be estimated since the lighting conditions were similar. The activity level substantially elevated SBP, but not DBP. Sleep, on the other hand, lowered the nighttime DBP, but has no effect on SBP. HR was affected both by activity and sleep. In accordance with previous studies, these results confirm that the steep BP increase in the morning is not driven by the circadian clock, but rather by sympathoadrenal factors related to awakening and corresponding anticipatory mechanisms. The effect on BT was not significant. To investigate the impact of light during the former dark time and darkness during the former light time, the CR-LL and CR-DD groups were each compared with the CR-LD group. Light delayed the evening decrease of BT

  7. α-Bromodiazoacetamides – a new class of diazo compounds for catalyst-free, ambient temperature intramolecular C–H insertion reactions

    Directory of Open Access Journals (Sweden)

    Åsmund Kaupang

    2013-07-01

    Full Text Available In this work, we introduce a new class of halodiazocarbonyl compounds, α-halodiazoacetamides, which through a metal-free, ambient-temperature thermolysis perform intramolecular C–H insertions to produce α-halo-β-lactams. When carried out with α-bromodiazoacetamides bearing cyclic side chains, the thermolysis reaction affords bicyclic α-halo-β-lactams, in some cases in excellent yields, depending on the ring size and substitution pattern of the cyclic amide side chains.

  8. Local Synthesis of Carbon Nanotubes in Silicon Microsystems: The Effect of Temperature Distribution on Growth Structure

    Directory of Open Access Journals (Sweden)

    Knut E. Aasmundtveit

    2013-07-01

    Full Text Available Local synthesis and direct integration of carbon nanotubes (CNTs into microsystems is a promising method for producing CNT-based devices in a single step, low-cost, and wafer-level, CMOS/MEMS-compatible process. In this report, the structure of the locally grown CNTs are studied by transmission imaging in scanning electron microscopy—S(TEM. The characterization is performed directly on the microsystem, without any post-synthesis processing required. The results show an effect of temperature on the structure of CNTs: high temperature favors thin and regular structures, whereas low temperature favors “bamboo-like” structures.

  9. Part 2. Association of daily mortality with ambient air pollution, and effect modification by extremely high temperature in Wuhan, China.

    Science.gov (United States)

    Qian, Zhengmin; He, Qingci; Lin, Hung-Mo; Kong, Lingli; Zhou, Dunjin; Liang, Shengwen; Zhu, Zhichao; Liao, Duanping; Liu, Wenshan; Bentley, Christy M; Dan, Jijun; Wang, Beiwei; Yang, Niannian; Xu, Shuangqing; Gong, Jie; Wei, Hongming; Sun, Huilin; Qin, Zudian

    2010-11-01

    Fewer studies have been published on the association between daily mortality and ambient air pollution in Asia than in the United States and Europe. This study was undertaken in Wuhan, China, to investigate the acute effects of air pollution on mortality with an emphasis on particulate matter (PM*). There were three primary aims: (1) to examine the associations of daily mortality due to all natural causes and daily cause-specific mortality (cardiovascular [CVD], stroke, cardiac [CARD], respiratory [RD], cardiopulmonary [CP], and non-cardiopulmonary [non-CP] causes) with daily mean concentrations (microg/m3) of PM with an aerodynamic diameter--10 pm (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), or ozone (O3); (2) to investigate the effect modification of extremely high temperature on the association between air pollution and daily mortality due to all natural causes and daily cause-specific mortality; and (3) to assess the uncertainty of effect estimates caused by the change in International Classification of Disease (ICD) coding of mortality data from Revision 9 (ICD-9) to Revision 10 (ICD-10) code. Wuhan is called an "oven city" in China because of its extremely hot summers (the average daily temperature in July is 37.2 degrees C and maximum daily temperature often exceeds 40 degrees C). Approximately 4.5 million residents live in the core city area of 201 km2, where air pollution levels are higher and ranges are wider than the levels in most cities studied in the published literature. We obtained daily mean levels of PM10, SO2, and NO2 concentrations from five fixed-site air monitoring stations operated by the Wuhan Environmental Monitoring Center (WEMC). O3 data were obtained from two stations, and 8-hour averages, from 10:00 to 18:00, were used. Daily mortality data were obtained from the Wuhan Centres for Disease Prevention and Control (WCDC) during the study period of July 1, 2000, to June 30, 2004. To achieve the first aim, we used a regression of

  10. Low-Pressure Self-Propagating High-Temperature Synthesis.

    Science.gov (United States)

    titanium carbide and titanium boride from the elements without applying isostatic pressure. The experimental study was limited to the synthesis of... titanium carbide and titanium bioride with and without a nickel matrix phase. SHS is now state of the art in the Soviet Union for the production of

  11. A meta-analysis of the effects of high ambient temperature on growth performance of growing-finishing pigs.

    Science.gov (United States)

    Renaudeau, D; Gourdine, J L; St-Pierre, N R

    2011-07-01

    High ambient temperature (T) is one of the most important climatic factors influencing pig performance. Increased T occurs sporadically during summer heat waves in temperate climates and year round in tropical climates. Results of published experiments assessing the effects of high T on pig performance are surprisingly variable. Thus, a meta-analysis was performed to aggregate our knowledge and attempt to explain differences in the results across studies on the effect of increased T on ADFI and ADG in growing-finishing pigs. Data for ADFI and ADG were extracted from 86 and 80 trials, respectively, from articles published in scientific journals indexed in PubMed, Science Direct, and from proceedings of scientific meetings through November 2009. Data on ADFI and ADG were analyzed using a linear mixed model that included the linear and the quadratic effects of T and BW, and their interactions as continuous, fixed effects variables, and the trial as a random effect factor (i.e., block). In addition, the effects of housing type (2 levels: individual and group housing) and the year of publication (3 levels: 1970 to 1989, 1990 to 1999, and 2000 to 2009) on the intercept and the linear regression term for T (i.e., the slope) were also tested. Results showed that high T had a curvilinear effect on ADFI and ADG and that this effect was more pronounced in heavier pigs. Across T, ADFI was less when pigs were group-housed. The intercept and the regression coefficient (slope) for T were significantly affected by the year of publication. The effect of increased T was greater in more contemporary works, suggesting that modern genotypes could be more sensitive to heat stress than older genotypes of lesser growth potential. In conclusion, pig performance decreases at an accelerating rate as T is increased. The large between-study variability on the effects of high T on pig performance is partially explained by differences in pig BW and to a lesser extent by the year the study was

  12. The effects of feed restriction and ambient temperature on growth and ascites mortality of broilers reared at high altitude.

    Science.gov (United States)

    Ozkan, S; Takma, C; Yahav, S; Sögüt, B; Türkmut, L; Erturun, H; Cahaner, A

    2010-05-01

    The development of ascites was investigated in broilers at low versus high altitudes, cold versus normal ambient temperatures (AT), and 3 feeding regimens. One-day-old chicks obtained at sea level were reared at high altitude (highA; 1,720 m; n = 576) with 2 AT treatments, low AT from 3 wk onward at highA (highA/cold) and normal AT from 3 wk onward at highA (highA/norm), or at sea level (normal AT from 3 wk onward at low altitude, lowA/norm; n = 540). Under highA/cold, AT ranged between 16 to 17 degrees C in the fourth week, 17 to 19 degrees C in the fifth week, and 19 to 21 degrees C thereafter. Under highA/norm and lowA/norm, AT was 24 degrees C in the fourth week and ranged between 22 to 24 degrees C thereafter. Broilers in each condition were divided into 3 groups: feed restriction (FR) from 7 to 14 d, FR from 7 to 21 d, and ad libitum (AL). Ascites mortality and related parameters were recorded. Low mortality (0.4%) occurred under lowA/norm conditions. Under highA/norm, mortality was lower in females (8.6%) than in males (13.8%) and was not affected by the feeding regimen. The highA/cold treatment resulted in higher mortality but only in males; it was 44.2% among highA/cold AL-fed males and only about 26% under the FR regimens, suggesting that FR helped some males to better acclimatize to the highA/cold environment and avoid ascites. However, mortality was only 13.3% in AL-fed males at highA/norm and FR did not further reduce the incidence of ascites under these conditions. Thus, avoiding low AT in the poultry house by slight heating was more effective than FR in reducing ascites mortality at highA. Compared with FR from 7 to 14 d, FR from 7 to 21 d did not further reduce mortality and reduced growth. At 47 d, the majority of surviving broilers at highA had high levels of hematocrit and right ventricle:total ventricle weight ratio (>0.29), but they were healthy and reached approximately the same BW as their counterparts at low altitude. This finding may

  13. High-Energy-Low-Temperature Technologies for the Synthesis of Nanoparticles: Microwaves and High Pressure

    Directory of Open Access Journals (Sweden)

    Witold Lojkowski

    2014-11-01

    Full Text Available Microwave Solvothermal Synthesis (MSS is a chemical technology, where apart from possible effects of microwaves on the chemical reaction paths, microwave heating allows the precise planning of a time-temperature schedule, as well as to achieve high super-saturation of the reagents uniformly in the reactor vessel. Thus, MSS is suitable for production of nanoparticles with small grain size distribution and a high degree of crystallinity. A further advantage of the technology is a much lower synthesis temperature than for gas phase, plasma or sol-gel technologies. New reactors have been developed to exploit these advantages of the MSS technology of nanoparticles synthesis and to scale up the production rate. Reactor design and realization has been shown to be decisive and critical for the control of the MSS technology. Examples of oxidic and phosphatic nanoparticles synthesis have been reported.

  14. CsF mediated rapid condensation of 1,3-cyclohexadione with aromatic aldehydes: Comparative study of conventional heating vs.ambient temperature

    Institute of Scientific and Technical Information of China (English)

    Kamalakar P. Nandre; Vijay S. Patil; Sidhanath V. Bhosale

    2011-01-01

    A mild, efficient and high yielding protocol for the synthesis of 2,2'-arylmethelene dicyclohexane-1,3-dione derivatives at room temperature and 9-aryl-l,8-dihydrooctahydroxanthene at conventional heating using cesium fluoride as a catalyst is reported. The major advantages of this reaction are excellent yield, very short reaction time and use of inexpensive catalyst.

  15. Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials

    Science.gov (United States)

    2008-04-15

    Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials Final Performance Report Contract Number...sintered commercially-available powders. Each project is summarized below: Synthesis : Zirconium diboride and a zirconium diboride/tantalum diboride...mixture were synthesized by solution-based processing. Zirconium n-propoxide was refluxed with 2,4-pentanedione to form zirconium diketonate . This compound

  16. Self-sustained high-temperature reactions: initiation, propagation and synthesis

    OpenAIRE

    Martinez Pacheco, M.

    2007-01-01

    Self-Propagating High-Temperature Synthesis (SHS), also called combustion synthesis is an exothermic and self-sustained reaction between the constituents, which has assumed significance for the production of ceramics and ceramic-metallic materials (cermets), because it is a very rapid processing technique without the need of complex furnaces. However, one of the drawbacks of this route is the high porosity of the final product (typically 50%). This implies the need for a subsequent densificat...

  17. Theoretical modelling of Staphylococcus aureus growth in a cooked meat product kept at ambient temperature using temperature profiles of selected Mexican cities Modelagem teórica de crescimento de Staphylococcus aureus em um produto à base de carne cozida deixada à temperatura ambiente, usando perfis de temperatura de cidades do México

    Directory of Open Access Journals (Sweden)

    Rosa Baeza

    2009-03-01

    Full Text Available A theoretical model is used to predict the growth of Staphylococcus aureus in a pasteurized meat product kept at ambient temperatures for several hours. For this purpose, the temperature profiles of some cities of Mexico were combined with literature data on the kinetics of S. aureus growth. As shown by theoretical predictions, if the food is kept at ambient temperature, the average daily temperature may not give accurate predictions.Um modelo teórico é utilizado para prever o crescimento de Staphylococcus aureus em um produto à base de carne (pasteurizado deixado por várias horas à temperatura ambiente. Para isso, perfis de temperatura de algumas cidades do México foram combinados com resultados de literatura sobre a cinética de crescimento de S. aureus. Como demonstrado por previsões teóricas, se o alimento é deixado à temperatura ambiente, a utilização da média diária da temperatura pode não dar previsões exatas.

  18. Ambient temperature deposition of gallium nitride/gallium oxynitride from a deep eutectic electrolyte, under potential control.

    Science.gov (United States)

    Sarkar, Sujoy; Sampath, S

    2016-05-11

    A ternary, ionically conducting, deep eutectic solvent based on acetamide, urea and gallium nitrate is reported for the electrodeposition of gallium nitride/gallium indium nitride under ambient conditions; blue and white light emitting photoluminescent deposits are obtained under potential control.

  19. Urease-mediated room-temperature synthesis of nanocrystalline titanium dioxide.

    Science.gov (United States)

    Johnson, John M; Kinsinger, Nichola; Sun, Chhay; Li, Dongsheng; Kisailus, David

    2012-08-29

    Enzymes are an important class of biological molecules whose specific functionalities can be exploited to perform tasks beyond the reach of conventional chemistry. Because they are operational under environmentally friendly, ambient conditions, the adaptation of these biomacromolecules can potentially be used to replace current energy-intensive and environmentally harsh synthesis methods for materials. Here we used a hydrolytic enzyme, urease, to modify the solution environment around a water-soluble and stable TiO(2) precursor to synthesize nanocrystalline titanium dioxide under environmentally benign conditions. This urease-mediated synthesis yields nearly monodisperse TiO(2) nanostructures with high surface area that can be utilized for numerous energy-based applications such as low-cost photovoltaics and photocatalysts.

  20. Characterization and synthesis of carbon aggregates in high temperature environment

    OpenAIRE

    2013-01-01

    Carbon materials in all its forms, from the natural carbon solid materials, as coal and graphite, to the synthesized carbon materials, as carbon black, pitch fibers, fullerenes, carbon nanotubes, etc,. have been object of many studies regarding their characteristics and behaviour due to their importance in the energy and industrial sectors. Recently, most of the research efforts have been focused on the synthesis of new carbon materials and in particular on their physico-chemical propertie...

  1. Efeito da temperatura ambiental na densidade e ponto de congelamento do leite de cabra Effects of ambiental temperature on density and freezing point of goat's milk

    Directory of Open Access Journals (Sweden)

    L.H.A. BRASIL

    1999-12-01

    14 days each one, during the which, the animals under heat stress were exposed to medium air temperature of 33,87ºC, between 8:00 and 17:00 hs including simulated solar radiation from 10:00 to 15:00 hs. On the second week of each experimental interval, individuality milk samples were collected dairy by morning and afternoon, adding preservative. In the end of the week, the samples of each milking were mixed, forming a composed samples which were effected pH, titratable acidity, density and crioscopic point. The results indicated that the obtained values for density and crioscopic point are compatible with the others authors have found it in other countries. It was verified biggers values for the density on the milk milked in the morning, in relation with the afternoon, being that the unequal interval between the milkings could influenced the results. It’s not observed significal statistic differences for this goat milk propriety in termoneutrality and heat stress conditions. To the crioscopic point it not verified statistical difference between the milk milked by morning and afternoon. There was significal statistic difference between the goat milk in termoneutrality and termic stress conditions, being the medium value bigger to the termoneutrality conditions.

  2. A new predictive dynamic model describing the effect of the ambient temperature and the convective heat transfer coefficient on bacterial growth.

    Science.gov (United States)

    Ben Yaghlene, H; Leguerinel, I; Hamdi, M; Mafart, P

    2009-07-31

    In this study, predictive microbiology and food engineering were combined in order to develop a new analytical model predicting the bacterial growth under dynamic temperature conditions. The proposed model associates a simplified primary bacterial growth model without lag, the secondary Ratkowsky "square root" model and a simplified two-parameter heat transfer model regarding an infinite slab. The model takes into consideration the product thickness, its thermal properties, the ambient air temperature, the convective heat transfer coefficient and the growth parameters of the micro organism of concern. For the validation of the overall model, five different combinations of ambient air temperature (ranging from 8 degrees C to 12 degrees C), product thickness (ranging from 1 cm to 6 cm) and convective heat transfer coefficient (ranging from 8 W/(m(2) K) to 60 W/(m(2) K)) were tested during a cooling procedure. Moreover, three different ambient air temperature scenarios assuming alternated cooling and heating stages, drawn from real refrigerated food processes, were tested. General agreement between predicted and observed bacterial growth was obtained and less than 5% of the experimental data fell outside the 95% confidence bands estimated by the bootstrap percentile method, at all the tested conditions. Accordingly, the overall model was successfully validated for isothermal and dynamic refrigeration cycles allowing for temperature dynamic changes at the centre and at the surface of the product. The major impact of the convective heat transfer coefficient and the product thickness on bacterial growth during the product cooling was demonstrated. For instance, the time needed for the same level of bacterial growth to be reached at the product's half thickness was estimated to be 5 and 16.5 h at low and high convection level, respectively. Moreover, simulation results demonstrated that the predicted bacterial growth at the air ambient temperature cannot be assumed to be

  3. Relation of ST-Segment Elevation Myocardial Infarction to Daily Ambient Temperature and Air Pollutant Levels in a Japanese Nationwide Percutaneous Coronary Intervention Registry.

    Science.gov (United States)

    Yamaji, Kyohei; Kohsaka, Shun; Morimoto, Takeshi; Fujii, Kenshi; Amano, Tetsuya; Uemura, Shiro; Akasaka, Takashi; Kadota, Kazushige; Nakamura, Masato; Kimura, Takeshi

    2017-03-15

    Effects of daily fluctuation of ambient temperature and concentrations of air pollutants on acute cardiovascular events have not been well studied. From January 2011 to December 2012, a total of 56,863 consecutive ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention were registered from 929 institutes with median interinstitutional distance of 2.6 km. We constructed generalized linear mixed models in which the presence or absence of patients with STEMI per day per institute was included as a binomial response variable, with daily meteorologic and environmental data obtained from their respective observatories nearest to the institutes (median distance of 9.7 and 5.6 km) as the explanatory variables. Both lower mean temperature and increase in maximum temperature from the previous day were independently associated with the STEMI occurrence throughout the year (odds ratio [OR] 0.925, 95% confidence interval [CI] 0.915 to 0.935, per 10°C, p variables. Both the absolute value and relative change in the ambient temperature were associated with the occurrence of STEMI; the associations with the air pollutant levels were less clear after adjustment for these meteorologic variables in Japan.

  4. Self propagating high temperature synthesis of metal oxides. Reactions in external magnetic fields

    CERN Document Server

    Aguas, M D

    2001-01-01

    The preparation of metal oxides by Self-Propagating High-Temperature Synthesis is reported. The reactions are started with a point source of ignition; typically a hot wire. A synthesis wave is observed moving out from the point source and reactions terminate in seconds. Products obtained can be classified into ferrites (magnetic applications) and stannates (gas sensing applications). Ferrites were synthesised under variable external magnetic fields. The synthesis wave is hotter in the presence of an external magnetic field for hard ferrite synthesis. For spinel ferrites the opposite was observed. Materials synthesised in the field show differences in their bulk magnetic properties (coercivity and saturation magnetisation), structures and microstructures. Combustion reactions in large fields revealed changes in unit cell volume (shrinkage was observed for hard ferrites while expansion was observed for spinel ferrites). SHS synthesised hard ferrites show two distinct components; one has large grain structure co...

  5. Advances in nanoscale alloys and intermetallics: low temperature solution chemistry synthesis and application in catalysis.

    Science.gov (United States)

    Jana, Subhra

    2015-11-21

    Based on the bottom-up chemistry techniques, the size, shape, and composition controlled synthesis of nanoparticles can now be achieved uniformly, which is of great importance to the nanoscience community as well as in modern catalysis research. The low-temperature solution-phase synthesis approach represents one of the most attractive strategies and has been utilized to synthesize nanoscale metals, alloys and intermetallics, including a number of new metastable phases. This perspective will highlight the solution-based nanoparticle synthesis techniques, a low-temperature platform, for the synthesis of size and shape-tunable nanoscale transition metals, alloys, and intermetallics from the literature, keeping a focus on the utility of these nanomaterials in understanding the catalysis. For each solution-based nanoparticle synthesis technique, a comprehensive overview has been given for the reported nanoscale metals, alloys, and intermetallics, followed by critical comments. Finally, their enhanced catalytic activity and durability as novel catalysts have been discussed towards several hydrogenation/dehydrogenation reactions and also for different inorganic to organic reactions. Hence, the captivating advantages of this controllable low-temperature solution chemistry approach have several important implications and together with them this approach provides a promising route to the development of next-generation nanostructured metals, alloys, and intermetallics since they possess fascinating properties as well as outstanding catalytic activity.

  6. Room-temperature Electrochemical Synthesis of Carbide-derived Carbons and Related Materials

    Energy Technology Data Exchange (ETDEWEB)

    Gogotsi, Yury [Drexel Univ., Philadelphia, PA (United States). Nanomaterials Group. Materials Science and Engineering Dept.

    2015-02-28

    This project addresses room-temperature electrochemical etching as an energy-efficient route to synthesis of 3D nanoporous carbon networks and layered 2D carbons and related structures, as well as provides fundamental understanding of structure and properties of materials produced by this method. Carbide-derived-carbons (CDCs) are a growing class of nanostructured carbon materials with properties that are desirable for many applications, such as electrical energy and gas storage. The structure of these functional materials is tunable by the choice of the starting carbide precursor, synthesis method, and process parameters. Moving from high-temperature synthesis of CDCs through vacuum decomposition above 1400°C and chlorination above 400°C, our studies under the previous DOE BES support led to identification of precursor materials and processing conditions for CDC synthesis at temperatures as low as 200°C, resulting in amorphous and highly reactive porous carbons. We also investigated synthesis of monolithic CDC films from carbide films at 250-1200°C. The results of our early studies provided new insights into CDC formation, led to development of materials for capacitive energy storage, and enabled fundamental understanding of the electrolyte ions confinement in nanoporous carbons.

  7. Room Temperature Synthesis of Magnetite (Fe{sub 3-{delta}O4}) Nanoparticles by a Simple Reverse Co-Precipitation Method

    Energy Technology Data Exchange (ETDEWEB)

    Mahmed, N; Soederberg, O; Hannula, S-P [Aalto University School of Science and Technology, Department of Materials Science and Engineering, PO Box 16200, FI-00076 Aalto (Finland); Heczko, O, E-mail: norsuria@cc.hut.f [Institute of Physics, Academy of Sciences, Czech Republic Na Slovance 2, CZ-182 21 Praha 8 (Czech Republic)

    2011-10-29

    Magnetite (Fe{sub 3-{delta}O4}) nanoparticles with the size less than 30 nm have been synthesized by using a simple reverse co-precipitation method at room temperature. During the process, ferrous sulfate (FeSO{sub 4{center_dot}}7H{sub 2}O) powder was used as an iron precursor, and ammonium hydroxide (NH{sub 4}OH) as a precipitating agent. The experiment was carried out in ambient atmosphere without any surfactant added. In this method, the base solution for the precipitation process was adjusted to have a pH value suitable for the formation of the magnetite phase. The iron salt precursor was added into the solution during the synthesis by two different synthesis protocols. The phase, morphology and magnetic characteristic of differently synthesized magnetite particles were characterized by using an X-ray diffraction (XRD), transmission electron microscope (TEM) and vibrating sample magnetometer (VSM). The morphologies of the particles were spherical or irregular in shape depending on the synthesis protocol used. Magnetic measurement shows that the particles are ferromagnetic at room temperature with relatively high saturation magnetization and low hysteresis. The saturation magnetization and magnetic hysteresis of the particles varied with preparation reaction conditions and the resulting oxidation state of the particles.

  8. FY07 LDRD Final Report Synthesis under High Pressure and Temperature of New Metal Nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Crowhurst, J C; Sadigh, B; Aberg, D; Zaug, J M; Goncharov, A F

    2008-09-23

    The original aim of this LDRD was to determine with unprecedented precision the melting curve of iron to geophysically relevant pressures. In the course of developing much of the technology and techniques required to obtain this information we have encountered and studied novel chemical reactions some of whose products are stable or metastable under ambient conditions. Specifically we have synthesized nitrides of the platinum group metals including platinum, iridium, and palladium. We have also carried out in depth first principles theoretical investigations into the nature of these materials. We believed that the scientific impact of continuing this work would be greater than that of the original goals of this project. Indeed the work has led to a number of high profile publications with additional publications in preparation. While nitrides of the transition metals are generally of tremendous technological importance, those of the noble metals in particular have enjoyed much experimental and theoretical attention in the very short time since they were first synthesized. The field was and clearly remains open for further study. While the scientific motivation for this research is different from that originally proposed, many of the associated methods in which we have now gained experience are similar or identical. These include use of the diamond anvil cell combined with technologies to generate high temperatures, the in-situ technique of Raman scattering using our purpose-built, state-of-the-art system, analytical techniques for determining the composition of recovered samples such as x-ray photoelectron spectroscopy, and finally synchrotron-based techniques such as x-ray diffraction for structural and equation of state determinations. Close interactions between theorists and experimentalists has and will continue to allow our group to rapidly and reliably interpret complicated results on the structure and dynamics of these compounds and also additional novel

  9. Ambient Space and Ambient Sensation

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    The ambient is the aesthetic production of the sensation of being surrounded. As a concept, 'ambient' is mostly used in relation to the music genre 'ambient music' and Brian Eno's idea of environmental background music. However, the production of ambient sensations must be regarded as a central...... aspect of the aesthetization of modern culture in general, from architecture, transport and urbanized lifeforms to film, sound art, installation art and digital environments. This presentation will discuss the key aspects of ambient aesthetization, including issues such as objectlessness...

  10. Process assessment of small scale low temperature methanol synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Hendriyana [Chemical Engineering Department, Faculty of Engineering, Jenderal Achmad Yani Univerity (Indonesia); Chemical Engineering Department, Faculty of Industrial Technology, InstitutTeknologi Bandung (Indonesia); Susanto, Herri, E-mail: herri@che.itb.ac.id; Subagjo [Chemical Engineering Department, Faculty of Industrial Technology, InstitutTeknologi Bandung (Indonesia)

    2015-12-29

    Biomass is a renewable energy resource and has the potential to make a significant impact on domestic fuel supplies. Biomass can be converted to fuel like methanol via several step process. The process can be split into following main steps: biomass preparation, gasification, gas cooling and cleaning, gas shift and methanol synthesis. Untill now these configuration still has a problem like high production cost, catalyst deactivation, economy of scale and a huge energy requirements. These problems become the leading inhibition for biomass conversion to methanol, which should be resolved to move towards the economical. To address these issues, we developed various process and new configurations for methanol synthesis via methyl formate. This configuration combining two reactors: the one reactor for the carbonylation of methanol and CO to form methyl formate, and the second for the hydrogenolysis of methyl formate and H{sub 2} to form two molecule of methanol. Four plant process configurations were compared with the biomass basis is 300 ton/day. The first configuration (A) is equipped with a steam reforming process for converting methane to CO and H{sub 2} for increasing H{sub 2}/CO ratio. CO{sub 2} removal is necessary to avoid poisoning the catalyst. COSORB process used for the purpose of increasing the partial pressure of CO in the feed gas. The steam reforming process in B configuration is not used with the aim of reducing the number of process equipment, so expect lower investment costs. For C configuration, the steam reforming process and COSORB are not used with the aim of reducing the number of process equipment, so expect lower investment costs. D configuration is almost similar to the configuration A. This configuration difference is in the synthesis of methanol which was held in a single reactor. Carbonylation and hydrogenolysis reactions carried out in the same reactor one. These processes were analyzed in term of technical process, material and energy

  11. Research on Ambient Adaptability of Temperature Measuring Device for Oil-Immersed Transformer%油浸变压器测温装置的环境适应性研究

    Institute of Scientific and Technical Information of China (English)

    戴缘生; 陕华平; 童在林; 李文

    2012-01-01

    The influencing mechanism of ambient temperature of oil surface thermometer is researched. The method to discern influence degree of ambient temperature of thermometer is presented.%研究了油面温度计的环境温度变化影响机理,提出了一套有效鉴别温度计环境温度影响量水平的方法。

  12. Effect of different levels of alpha tocopherol on performance traits, serum antioxidant enzymes, and trace elements in Japanese quail ( Coturnix coturnix japonica under low ambient temperature

    Directory of Open Access Journals (Sweden)

    Assar Ali Shah

    Full Text Available ABSTRACT This study was designed to find the effect of vitamin E supplementation on growth, serum antioxidant enzymes, and some trace elements in Japanese quail (Coturnix coturnix japonica under low ambient temperature. A total of 180 day-old Japanese quails were randomly divided into four groups and provided with 0 (group A, 50 (group B, 100 (group C, and 150 IU/kg (group D vitamin E (dl-α-tocopherol acetate under an average temperature of 9±0.5 °C for an experimental period of 42 days. The result showed that feed intake per day, body weight, weight gain per day, and feed conversion ratio did not differ significantly between the groups. Serum concentrations of superoxide and glutathione peroxidase were significantly high in birds supplemented with 150 mg/kg of vitamin E. The concentration of aspartate aminotransferase was not significantly affected between the control and treated groups; however, alanine transaminase concentration significantly reduced in group D. Zinc concentration in the blood increased significantly in group D, with no significant effect on copper and manganese between the control and treated groups. Vitamin E at the level of 150 IU/kg of feed improves the blood antioxidant status and zinc concentration, with no effect on the performance traits of quail reared under low ambient temperature.

  13. Fuel Maps for the GEP 6.5LT Engine When Operating on at J/JP-8 Fuel Blends at Ambient and Elevated Temperatures

    Science.gov (United States)

    2015-04-01

    77° +/- 4°F 120° +/- 4°F Fuel Inlet Temp 86° +/- 4°F 145° +/- 4°F Engine Coolant Temp 205° +/- 4°F 218 ° +/- 4°F The statement of work indicated a...UNCLASSIFIED UNCLASSIFIED FUEL MAPS FOR THE GEP 6.5LT ENGINE WHEN OPERATING ON ATJ/JP-8 FUEL BLENDS AT AMBIENT AND ELEVATED TEMPERATURES...UNCLASSIFIED Disclaimers Reference herein to any specific commercial company, product, process, or service by trade name, trademark, manufacturer , or

  14. Synthesis, characterization and magnetic properties of room-temperature nanofluid ferromagnetic graphite

    OpenAIRE

    Souza, NS; Sergeenkov, S.; Speglich, C.; Rivera, VAG; Cardoso, CA; Pardo, H.; Mombru, AW; Rodrigues, AD; de Lima, OF; Araujo-Moreira, FM

    2009-01-01

    We report the chemical synthesis route, structural characterization, and physical properties of nanofluid magnetic graphite (NFMG) obtained from the previously synthesized bulk organic magnetic graphite (MG) by stabilizing the aqueous ferrofluid suspension with an addition of active cationic surfactant. The measured magnetization-field hysteresis curves along with the temperature dependence of magnetization confirmed room-temperature ferromagnetism in both MG and NFMG samples. (C) 2009 Americ...

  15. Room-temperature synthesis of enantioenriched non-protected cyanohydrins using vanadium(salalen) catalyst.

    Science.gov (United States)

    Sakai, Yoshifumi; Mitote, Junko; Matsumoto, Kazuhiro; Katsuki, Tsutomu

    2010-08-21

    Room-temperature synthesis of enantioenriched non-protected cyanohydrins using acetone cyanohydrin as the cyanide source was achieved by V(salalen) catalyst. Aliphatic aldehydes underwent the cyanation with 89-95% ee in the presence of only 0.2-0.4 mol% catalyst. Aromatic cyanohydrins were also obtained in high enantiomeric excesses under modified conditions.

  16. Low-temperature, template-free synthesis of single-crystal bismuth telluride nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Purkayastha, A. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Lupo, F. [Max Planck Institut fuer Metallforschung, Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Kim, S.; Borca-Tasciuc, T. [Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Ramanath, G. [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Max Planck Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-70569 Stuttgart (Germany)

    2006-02-17

    Synthesis of single-crystal bismuth telluride nanorods is reported by using a low-temperature, template-free approach. Films of thioglycolic acid functionalized nanorods doped with sulfur exhibit n-type behavior with a high Seebeck coefficient, holding promise for thermoelectric device applications. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  17. EPISTEMOLOGIA AMBIENTAL

    OpenAIRE

    2012-01-01

    O livro Epistemologia Ambiental traz uma rica discussão sobre a questão ambiental, abordando teorias relevantes para o entendimento e interpretação da crise atual, orientando para a construção de novas racionalidades e a constituição de um saber ambiental. A obra vem compartimentada em cinco capítulos distribuídos em 240 páginas. 

  18. Room and low temperature synthesis of carbon nanofibres

    CERN Document Server

    Boskovic, B O

    2002-01-01

    Carbon nanotubes and nanofibres have attracted attention in recent years as new materials with a number of very promising potential applications. Carbon nanotubes are potential candidates for field emitters in flat panel displays. Carbon nanofibres could also be used as a hydrogen storage material and as a filling material in polymer composites. Carbon nanotubes are already used as tips in scanning probe microscopy due to their remarkable mechanical and electrical properties, and could be soon used as nanotweezers. Use of carbon nanotubes in nanoelectronics will open further miniaturisation prospects. Temperatures ranging from 450 to 1000 deg C have been a required for catalytic growth of carbon nanotubes and nanofibres. Researchers have been trying to reduce the growth temperatures for decades. Low temperature growth conditions will allow the growth of carbon nanotubes on different substrates, such glass (below 650 deg C) and as plastics (below 150 deg C) over relatively large areas, which is especially suit...

  19. Temperature control of microheaters for localized carbon nanotube synthesis.

    Science.gov (United States)

    Lu, Jingyu; Xu, Ting; Miao, Jianmin

    2011-12-01

    The temperatures of microheater devices for the localized growth of carbon nanotubes (CNTs) were brought under control to a great extent by providing the appropriate electric load (direct current or voltage) to the microheater circuit. The electrical-thermal coupled field simulations show that high temperatures only appear in very local areas under certain electric load. The infrared image of the produced microheater device agrees well with the simulation results. By applying the selected current to the fabricated microheater device and providing the mixed reaction gases, long, dense, and vertically well aligned CNT bundles were successfully grown very locally on the substrate. The control of temperatures paves the way to the localized growth of CNTs with good compatibility with CMOS process, and thus facilitating the direct integration of CNTs into future micro/nano electronics as interconnects. What's more, the method will also excite more in depth investigations on the applications of microheaters in many other fields.

  20. Effect of different arbuscular mycorrhizal fungi on growth and physiology of maize at ambient and low temperature regimes

    DEFF Research Database (Denmark)

    Chen, Xiaoying; Song, Fengbin; Liu, Fulai;

    2014-01-01

    and soluble sugar contents under low temperature condition. The activities of catalase (CAT) and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology...

  1. Low temperature solid-state synthesis of nanocrystalline gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Liangbiao, E-mail: wlb6641@163.com [Hefei National Laboratory for Physical Science at Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi, Liang; Li, Qianwen; Si, Lulu; Zhu, Yongchun; Qian, Yitai [Hefei National Laboratory for Physical Science at Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2012-11-15

    Graphical abstract: Display Omitted Highlights: ► GaN nanocrystalline was prepared via a solid-state reacion at relatively low temperature. ► The sizes and crystallinities of the GaN samples obtained at the different temperatures are investigated. ► The GaN sample has oxidation resistance and good thermal stability below 1000 °C. -- Abstract: Nanocrystalline gallium nitride was synthesized by a solid-state reaction of metallic magnesium powder, gallium sesquioxide and sodium amide in a stainless steel autoclave at a relatively low temperature (400–550 °C). The structures and morphologies of the obtained products were derived from X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). XRD patterns indicated that the products were hexagonal GaN (JCPDS card no. 76-0703). The influence of reaction temperature on size of the products was studied by XRD and TEM. Furthermore, the thermal stability and oxidation resistance of the nanocrystalline GaN were also investigated. It had good thermal stability and oxidation resistance below 800 °C in air.

  2. Synthesis and characterization of flexible thermographic phosphor temperature sensors

    Science.gov (United States)

    Mitchell, Katherine E.; Gardner, Victor; Allison, Stephen W.; Sabri, Firouzeh

    2016-10-01

    The temperature dependence of the emission characteristics of thermographic phosphors has been used extensively for surface temperature measurements of systems where thermal management is critical for the safe operation of the system. The instantaneous, remote, and highly accurate nature of this form of temperature measurement makes it a very attractive measurement technique. However, the destructive nature of depositing phosphors directly onto the surface of interest and the complications of working with fine powders has limited the use of this technique in all areas. This work focuses on the design and characterization of polymer-encapsulated thermographic phosphor flexible sensors for surface temperature assessment. La2O2S:Eu powder was embedded in an elastomeric sleeve at concentrations of 10%, 25%, and 50% wt. and fully characterized. The effect of spin-coating on emission characteristics of La2O2S:Eu was tested and the decay times were compared to results obtained from bulk-doped samples previously created by the authors.

  3. Synthesis of silicon carbide ceramics at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    McMillan, S.M.; Brook, R.J. [Univ. of Oxford (United Kingdom)

    1995-09-01

    This paper reports observations of the direct transformation of a polymeric precursor into amorphous Si-C, and crystalline SiC at low temperatures, and the use of this precursor as a binder for the productin of SiC composites.

  4. Self-propagating high-temperature synthesis in Ti-W-C system

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effects of W content and preheat temperature on combustion temperature, combustion velocity and product components of self-propagating high-temperature synthesis(SHS) in Ti-W-C system were investigated. The results show that with decreasing W content and increasing preheat temperature, the combustion temperature and combustion velocity increases, the SHS reaction becomes complete and the particle size of product increases. There exist two combustion mechanisms. When Ti powder in combustion front was molten by high combustion temperature, SHS product was formed by melt-solution-precipitation mechanism. When the combustion temperature was not high enough to make Ti powder melt in combustion front, the product was formed through diffusion-solution-in-solid-state.

  5. Effect of daily fluctuations in ambient temperature on reproductive failure traits of Landrace and Yorkshire sows under Thai tropical environmental conditions.

    Science.gov (United States)

    Jaichansukkit, Teerapong; Suwanasopee, Thanathip; Koonawootrittriron, Skorn; Tummaruk, Padet; Elzo, Mauricio A

    2017-03-01

    The aim of this study was to determine the effects of daily ranges and maximum ambient temperatures, and other risk factors on reproductive failure of Landrace (L) and Yorkshire (Y) sows under an open-house system in Thailand. Daily ambient temperatures were added to information on 35,579 litters from 5929 L sows and 1057 Y sows from three commercial herds. The average daily temperature ranges (ADT) and the average daily maximum temperatures (PEAK) in three gestation periods from the 35th day of gestation to parturition were classified. The considered reproductive failure traits were the occurrences of mummified fetuses (MM), stillborn piglets (STB), and piglet death losses (PDL) and an indicator trait for number of piglets born alive below the population mean (LBA). A multiple logistic regression model included farrowing herd-year-season (HYS), breed group of sow (BG), parity group (PAR), number of total piglets born (NTB), ADT1, ADT2, ADT3, PEAK1, PEAK2, and PEAK3 as fixed effects, while random effects were animal, repeated observations, and residual. Yorkshire sows had a higher occurrence of LBA than L sows (P = 0.01). The second to fifth parities sows had lower reproductive failures than other parities. The NTB regression coefficients of log-odds were positive (P < 0.01) for all traits. Narrower ranges of ADT3 increased the occurrence of MM, STB, and PDL (P < 0.01), while higher PEAK3 increased the occurrence of MM, STB, PDL, and LBA (P < 0.001). To reduce the risk of reproductive failures, particularly late in gestation, producers would need to closely monitor their temperature management strategies.

  6. The effects of ambient temperature and mixing time of glass ionomer cement material on the survival rate of proximal ART restorations in primary molars

    Directory of Open Access Journals (Sweden)

    Arthur M Kemoli

    2014-01-01

    Full Text Available Objective: Temperature fluctuations and material mixing times are likely to affect the consistency and integrity of the material mixture, and hence the restoration made out of it. The purpose of the present study was to determine the influence of the ambient temperature and the mixing time of glass ionomer cement (GIC restorative material on the survival rate of proximal atraumatic restorative treatment (ART restorations placed in primary molars. Materials and Methods: A total of 804 restorations were placed in the primary molars of 6-8-year-olds using the ART approach. The restorations were then followed for a period of 2 years and evaluated at given intervals. The data collected were analyzed using SPSS computer statistical program, and the results tested and compared using the Chi-square, Kaplan Meier survival analysis and Cox Proportional hazard statistical tests. Results: The cumulative survival rate of the restorations dropped from the initial 94.4% to 30.8% at the end of 2 years. The higher survival rate of the restorations was associated with the experienced operators and assistants when using the rubber dam isolation method. However, there was no statistically significant difference in the survival rate of the restorations when related to the room temperature and the mixing time of the GIC materials used in spite of the variations in the temperature recoded and the methods used in mixing the materials. Conclusion: The ambient temperature and mixing time of GIC did not have a significant effect on the survival of the proximal ART restorations.

  7. Influência da temperatura na solubilidade de beta-caroteno em solventes orgânicos à pressão ambiente Effect of temperature on the solubility of beta-carotene in organic solvents under ambient pressure

    Directory of Open Access Journals (Sweden)

    Marcus Vinícius Três

    2007-12-01

    Full Text Available O presente trabalho reporta dados experimentais de solubilidade em pressão ambiente de beta-caroteno em solventes orgânicos puros (etanol, acetona, acetato de etila e diclorometano e em misturas de tais solventes no intervalo de temperatura de 10 a 60 °C. Para este fim, adotou-se o método gravimétrico para a determinação da solubilidade, utilizando células encamisadas de equilíbrio. Os resultados mostraram que valores mais elevados de solubilidade são obtidos quando foram empregados solventes com parâmetros de solubilidade mais próximos daquele do soluto. Verificou-se que o aumento da temperatura, tanto para solventes puros, como para as misturas de solventes, acarretou num aumento da solubilidade do beta-caroteno para todas as condições experimentais. Observou-se ainda, que nas condições experimentais investigadas, não houve sinergismo significativo para as misturas de solventes quando comparadas aos valores de solubilidade obtidos para os solventes puros. O modelo UNIFAC se mostrou útil na previsão qualitativa dos resultados de solubilidade.This work reports experimental data of the solubility of beta-carotene in pure acetone, ethyl acetate, ethanol and dichloromethane and in mixtures of these organic solvents in the temperature range of 10 to 60 °C under ambient pressure. The gravimetric method was employed to determine the solubility, using glass equilibrium cells. The results showed that the best solvents were those having solubility parameter values close to that of the solute. It was found that raising the temperature caused the solute solubility values for both pure and solvent mixtures to increase under all the experimental conditions. Moreover, no synergetic effects were observed on the solubility of beta-carotene in solvent mixtures compared to pure solvents in the temperature range investigated. The UNIFAC model proved to be useful in predicting the solubility data.

  8. Nanocarbon synthesis by high-temperature oxidation of nanoparticles

    Science.gov (United States)

    Nomura, Ken-Ichi; Kalia, Rajiv K.; Li, Ying; Nakano, Aiichiro; Rajak, Pankaj; Sheng, Chunyang; Shimamura, Kohei; Shimojo, Fuyuki; Vashishta, Priya

    2016-04-01

    High-temperature oxidation of silicon-carbide nanoparticles (nSiC) underlies a wide range of technologies from high-power electronic switches for efficient electrical grid and thermal protection of space vehicles to self-healing ceramic nanocomposites. Here, multimillion-atom reactive molecular dynamics simulations validated by ab initio quantum molecular dynamics simulations predict unexpected condensation of large graphene flakes during high-temperature oxidation of nSiC. Initial oxidation produces a molten silica shell that acts as an autocatalytic ‘nanoreactor’ by actively transporting oxygen reactants while protecting the nanocarbon product from harsh oxidizing environment. Percolation transition produces porous nanocarbon with fractal geometry, which consists of mostly sp2 carbons with pentagonal and heptagonal defects. This work suggests a simple synthetic pathway to high surface-area, low-density nanocarbon with numerous energy, biomedical and mechanical-metamaterial applications, including the reinforcement of self-healing composites.

  9. Synthesis of cadmium chalcogenide nanotubes at room temperature

    KAUST Repository

    Pan, Jun

    2012-10-01

    Cadmium chalcogenide (CdE, E=S, Se, Te) polycrystalline nanotubes have been synthesized from precursor of CdS/cadmium thiolate complex at room temperature. The precursor was hydrothermally synthesized at 180 °C using thioglycolic acid (TGA) and cadmium acetate as starting materials. The transformation from the rod-like precursor of CdS/cadmium thiolate complex to CdS, CdSe and CdTe nanotubes were performed under constant stirring at room temperature in aqueous solution containing S 2-, Se 2- and Te 2-, respectively. The nanotube diameter can be controlled from 150 to 400 nm related to the dimension of templates. The XRD patterns show the cadmium chalcogenide nanotubes all corresponding to face-centered cubic structure. © 2012 Elsevier B.V. All rights reserved.

  10. Synthesis of hydrocarbon fluid inclusions at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Pironon, J. (Centre de Recherche sur la Geologie de l' Uranium and GS-CNRS CREGU, Vandoeuvre-les-Nancy (France))

    Hydrocarbon fluid inclusions have been synthesized in halogenide and sulfate crystals at low temperature (<100C) and atmospheric pressure. Water-immiscible hydrocarbon droplets were either trapped separately or with an aqueous and/or a vapor phase. Impurities on the crystal surface were verified by infrared microspectrometry, and the similarity between the initial liquid and the liquid trapped in the inclusion was documented by Raman microspectrometry for nonfluorescent compounds. This inclusion type represents a new tool for understanding inclusion-formation phenomena and for the calibration of techniques used in hydrocarbon fluid-inclusion analysis ({mu}FT-IR, {mu}Raman, {mu}UV-fluorescence, gas chromatography, mass spectrometry); these inclusions allow one to obtain microthermometric calibration curves with a high precision at low temperature.

  11. Synthesis of nanocrystalline high-temperature zirconia phases

    NARCIS (Netherlands)

    Petrunin, VF; Popov, VV; Zhu, HZ; Timofeev, AA

    2004-01-01

    The formation of ZrO2 nanocrystals during heat treatment of amorphous ZrO(OH)(2) is studied. The results indicate that the high-temperature phases of ZrO2 (T-ZrO2 and trace amounts of C-ZrO2) can be produced and stabilized at 350-375degreesC in nanoparticles with a size of coherently scattering doma

  12. Combustion and Plasma Synthesis of High Temperature Materials

    Science.gov (United States)

    1989-10-01

    8217 Maltsev [33-35]. They used microthermocouple and optico -spectral methods for the determination of temperature profiles. The investigations showed...coating. A modification to this device using an ultrasonic sensor allows for coating delamination detection. Reference 3 describes details of this...adhesion pin-on-disc with acoustic emission sensor ) are candidates for application as plasma materials processing diagnostic tools, each with its own

  13. Det ambiente

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Om begrebet "det ambiente", der beskriver, hvad der sker, når vi fornemmer baggrundsmusikkens diskrete beats, betragter udsigten gennem panoramavinduet eller tager 3D-brillerne på og læner os tilbage i biografsædet. Bogen analyserer, hvorfan ambiente oplevelser skabes, og hvilke konsekvenser det...

  14. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under th

  15. Derecho Ambiental

    OpenAIRE

    2014-01-01

    Es indudable la relevancia para la vida del planeta proteger el ambiente. De ahí que a lo largo de las últimas decadas el derecho ambiental se ha consolidado como una nueva y vital rama del derecho público.

  16. Design and development of an ambient-temperature continuously-rotating achromatic half-wave plate for CMB polarization modulation on the POLARBEAR-2 experiment

    Science.gov (United States)

    Hill, Charles A.; Beckman, Shawn; Chinone, Yuji; Goeckner-Wald, Neil; Hazumi, Masashi; Keating, Brian; Kusaka, Akito; Lee, Adrian T.; Matsuda, Frederick; Plambeck, Richard; Suzuki, Aritoki; Takakura, Satoru

    2016-07-01

    We describe the development of an ambient-temperature continuously-rotating half-wave plate (HWP) for study of the Cosmic Microwave Background (CMB) polarization by the POLARBEAR-2 (PB2) experiment. Rapid polarization modulation suppresses 1/f noise due to unpolarized atmospheric turbulence and improves sensitivity to degree-angular-scale CMB fluctuations where the inflationary gravitational wave signal is thought to exist. A HWP modulator rotates the input polarization signal and therefore allows a single polarimeter to measure both linear polarization states, eliminating systematic errors associated with differencing of orthogonal detectors. PB2 projects a 365-mm-diameter focal plane of 7,588 dichroic, 95/150 GHz transition-edge-sensor bolometers onto a 4-degree field of view that scans the sky at 1 degree per second. We find that a 500-mm-diameter ambient-temperature sapphire achromatic HWP rotating at 2 Hz is a suitable polarization modulator for PB2. We present the design considerations for the PB2 HWP, the construction of the HWP optical stack and rotation mechanism, and the performance of the fully-assembled HWP instrument. We conclude with a discussion of HWP polarization modulation for future Simons Array receivers.

  17. Design and development of an ambient-temperature continuously-rotating achromatic half-wave plate for CMB polarization modulation on the POLARBEAR-2 experiment

    CERN Document Server

    Hill, Charles A; Chinone, Yuji; Goeckner-Wald, Neil; Hazumi, Masashi; Keating, Brian; Kusaka, Akito; Lee, Adrian T; Matsuda, Frederick; Plambeck, Richard; Suzuki, Aritoki; Takakura, Satoru

    2016-01-01

    We describe the development of an ambient-temperature continuously-rotating half-wave plate (HWP) for study of the Cosmic Microwave Background (CMB) polarization by the POLARBEAR-2 (PB2) experiment. Rapid polarization modulation suppresses 1/f noise due to unpolarized atmospheric turbulence and improves sensitivity to degree-angular-scale CMB fluctuations where the inflationary gravitational wave signal is thought to exist. A HWP modulator rotates the input polarization signal and therefore allows a single polarimeter to measure both linear polarization states, eliminating systematic errors associated with differencing of orthogonal detectors. PB2 projects a 365-mm-diameter focal plane of 7,588 dichroic, 95/150 GHz transition-edge-sensor bolometers onto a 4-degree field of view that scans the sky at $\\sim$ 1 degree per second. We find that a 500-mm-diameter ambient-temperature sapphire achromatic HWP rotating at 2 Hz is a suitable polarization modulator for PB2. We present the design considerations for the PB...

  18. Synthesis of MIL-100(Fe at Low Temperature and Atmospheric Pressure

    Directory of Open Access Journals (Sweden)

    Jing Shi

    2013-01-01

    Full Text Available MIL-100(Fe, a mesoporous metal-organic framework (MOF, has a large BET specific surface area and pore volume with the presence of a significant amount of accessible Lewis acid metal sites upon dehydration. The structural characteristics of MIL-100(Fe make it a good candidate for potential applications in gas storage, separation, and heterogeneous catalysis. Mainly, this MOF is obtained by the hydrothermal synthesis in a Teflon-lined autoclave at high temperature (>150°C under static conditions. However, this method has several disadvantages such as high temperature, high (autogenous pressure, long time, and comparable low MOF yield. Therefore, development of a facile method for synthesis of MIL-100(Fe is vitally important for fundamental understanding and practical application. Herein, MIL-100(Fe is synthesized by a facile low-temperature (90% still could be achieved, suggesting that this simple and energy saving method has the potential to be used practically.

  19. Synthesis of ZnO Nanostructures for Low Temperature CO and UV Sensing

    Directory of Open Access Journals (Sweden)

    Nazar Abbas Shah

    2012-10-01

    Full Text Available In this paper, synthesis and results of the low temperature sensing of carbon monoxide (CO gas and room temperature UV sensors using one dimensional (1-D ZnO nanostructures are presented. Comb-like structures, belts and rods, and needle-shaped nanobelts were synthesized by varying synthesis temperature using a vapor transport method. Needle-like ZnO nanobelts are unique as, according to our knowledge, there is no evidence of such morphology in previous literature. The structural, morphological and optical characterization was carried out using X-ray diffraction, scanning electron microscopy and diffused reflectance spectroscopy techniques. It was observed that the sensing response of comb-like structures for UV light was greater as compared to the other grown structures. Comb-like structure based gas sensors successfully detect CO at 75 °C while other structures did not show any response.

  20. Ambient Dried Aerogels

    Science.gov (United States)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  1. Neutral gas temperature maps of the pin-to-plate Argon micro discharge into the ambient air

    CERN Document Server

    Xu, Shaofeng; Majeed, Asif

    2015-01-01

    This study is designed to explore the two dimensional temperature maps of the atmospheric argon discharge consisting of pin-to-plane electrodes supplied by a high voltage DC source. After checking the stability of the micro discharge, the two dimensional image plane focused by a quartz lens was scanned by the fiber probe driven by a 3D Mobile Platform. The rotational and vibrational temperatures are calculated using nitrogen emissions collected by the high resolution spectrometer and high sensitive intensified charge coupled device (ICCD). The rotational temperature varies from 1558.15 K to 2621.14 K and vibrational temperature varies from 3010.38 K to 3774.69 K, indicating a great temperature gradient due to small discharge size. The temperature maps show a lateral expansion and a sharp truncation in the radial direction. A double layers discharge is identified, where an arc discharge coats the glow discharge.

  2. Tensile behavior of a 2D woven C/SiC composite at ambient and elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Camus, G.; Barbier, J.E. [Laboratorie des Composites Thermostructuraux, Pessac (France)

    1995-12-01

    A 2D reinforced composite of carbon fibers in a SiC-CVI processed matrix was tested under monotonic tension at various temperatures ranging from room temperature to 1600{degrees}C in an inert atmosphere. Up to 1000{degrees}C, the mechanical behavior remained elastic-damageable and changes proved to be essentially governed by the progressive vanishing of the processing-related thermal residual stresses. Beyond this temperature, irreversible residual strains (i.e. unrecovered upon compression) were observed whereas the tensile behavior became increasingly time-temperature dependent. The mechanisms responsible for such a behavior are reported and discussed.

  3. EFFECT OF PRE-TREATMENTS ON PHYSICO-CHEMICAL COMPOSITION OF DEHYDRATED JACKFRUIT CHIPS DURING STORAGE AT AMBIENT TEMPERATURE

    Directory of Open Access Journals (Sweden)

    ROHAN R. PATIL, MANDAR KHANVILKAR, D. N. MOKAT*, P. P. RELEKAR AND R K. H. PUJARI

    2014-08-01

    The dehydrated chips of jackfruit pre-treated with ascorbic acid (T4 recorded maximum mean score for colour, flavour and texture irrespective of storage period. The organoleptic scores of these dehydrated jackfruit chips for all above attributes were declined with the increase in storage period from 0 to 60 days. The dehydrated chips pre-treated with ascorbic acid (T4 recorded maximum overall acceptability score of 6.91 at 60 days of storage which clearly indicated its suitability for making good quality chips and also for storing them for 60 days at ambient conditions without much loss of sensory and nutritional qualities of chips.Keywords: Physico chemical composition of dehydrated chips of jackfruit (Artocarpus heterophyllus and storage period.

  4. Low-Temperature Synthesis of Superconducting Nanocrystalline MgB2

    Directory of Open Access Journals (Sweden)

    Jun Lu

    2010-01-01

    Full Text Available Magnesium diboride (MgB2 is considered a promising material for practical application in superconducting devices, with a transition temperature near 40 K. In the present paper, nanocrystalline MgB2 with an average particle size of approximately 70 nm is synthesized by reacting LiBH4 with MgH2 at temperatures as low as 450°C. This synthesis approach successfully bypasses the usage of either elemental boron or toxic diborane gas. The superconductivity of the nanostructures is confirmed by magnetization measurements, showing a superconducting critical temperature of 38.7 K.

  5. Low-temperature synthesis of ZnO nanonails

    Science.gov (United States)

    Song, Xubo; Zhang, Yaohua; Zheng, Jie; Li, Xingguo

    2007-09-01

    Wurtzite ZnO nanonails on silicon substrate were successfully synthesized by thermal vapor transport and condensation method at a low temperature without a metal catalyst. Pure Zn powders were used as raw material and O2/Ar powders as source gas. The products were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that the deposited nanostructures include aligned ZnO nanonails. The ZnO nanonails, with crystalline cap and small-diameter shafts, grow along the c-axis. The optical properties have been revealed by photoluminescence spectra. We considered that the ZnO nanonails growth is a vapor solid process.

  6. Synthesis of tin oxide nanospheres under ambient conditions and their strong adsorption of As(III) from water.

    Science.gov (United States)

    Zhang, Ge; Sun, Wuzhu; Liu, Lingmei; Yang, Weiyi; Xu, Zhengchao; Li, Qi; Shang, Jian Ku

    2015-11-07

    The development of highly efficient As(iii) adsorbents is critical to largely simplify the arsenic treatment process and lower its cost. For the first time, SnO2 nanospheres were demonstrated to possess a highly efficient As(iii) adsorption capability from water in a near neutral pH environment as predicted by the material criterion we recently developed for the selection of highly efficient arsenic adsorbents. These SnO2 nanospheres were synthesized by a simple and cost-effective hydrolysis process with the assistance of ethyl acetate under ambient conditions, which had a good dispersity, a narrow size distribution, a relatively large specific surface area, and a porous structure. A fast As(iii) adsorption was observed in the kinetics study on these SnO2 nanospheres, and their Langmuir adsorption capacity was determined to be ∼112.7 mg g(-1) at pH ∼7. The As(iii) adsorption mechanism on SnO2 nanospheres was examined by both macroscopic and microscopic techniques, which demonstrated that it followed the inner-sphere complex model. These SnO2 nanospheres demonstrated effective As(iii) adsorption even with exceptionally high concentrations of co-existing ions, and a good regeneration capability by washing with NaOH solution.

  7. A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions.

    Science.gov (United States)

    Lawrence, Marlon; Testen, Anze; Koklic, Tilen; Smithies, Oliver

    2016-02-05

    Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl₄ to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na(+)[Au(OH₄-x)Clx](-)) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated >300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.

  8. A light-modified ferroelectric resistive switching behavior in Ag/BaMoO4/FTO device at ambient temperature

    Science.gov (United States)

    Zhao, W. X.; Sun, B.; Liu, Y. H.; Wei, L. J.; Li, H. W.; Chen, P.

    2014-12-01

    BaMoO4 powder was prepared by a facile hydrothermal synthesis. And the BaMoO4/FTO device was fabricated by a spin-coated method, in which the thickness of BaMoO4 layer is about 20 μm. The bipolar resistive switching effect has been observed in Ag/BaMoO4/FTO device. Moreover, the resistive switching effect of the device is greatly improved by white light irradiation. The resistive switching behavior is explained by the polarization reversal that changes the charge distribution and modulates the Schottky barriers.

  9. Thermal degradation of concrete in the temperature range from ambient to 315{degree} C (600{degree} F). Revision 10/96

    Energy Technology Data Exchange (ETDEWEB)

    Kassir, M.K.; Bandyopadhyay, K.K.; Reich, M.

    1996-10-01

    This report is concerned with determining the effect of elevated temperatures on the behavior of concrete. Emphasis is placed on quantifying the degree of potential degradation of the physical properties of concrete in high-level waste storage tanks. The temperature elevation range of interest is from ambient to 315 C (600 F). The literature has been reviewed to examine the applicable experimental data and quantify the degradation in the concrete and reinforcing steel. Since many variables and test conditions control the results in the data base, upper and lower bounds of the degraded properties at temperatures applicable to the environments of the storage tanks are summarized and presented in explicit forms. For properties with large data bases, a normal logarithmic distribution of the data is assumed and a statistical analysis is carried out to find the mean and 84% values of the degraded property in the temperature range of interest. Such results are useful in assessing the effect of elevated temperatures on the structural behavior of the tanks. In addition, the results provide the technical basis for a parametric study that may be necessary to investigate the thermal aspects of the structural integrity of the tanks. 50 refs., 23 figs.

  10. Online Estimation of Model Parameters and State of Charge of LiFePO4 Batteries Using a Novel Open-Circuit Voltage at Various Ambient Temperatures

    Directory of Open Access Journals (Sweden)

    Fei Feng

    2015-04-01

    Full Text Available This study describes an online estimation of the model parameters and state of charge (SOC of lithium iron phosphate batteries in electric vehicles. A widely used SOC estimator is based on the dynamic battery model with predeterminate parameters. However, model parameter variances that follow with their varied operation temperatures can result in errors in estimating battery SOC. To address this problem, a battery online parameter estimator is presented based on an equivalent circuit model using an adaptive joint extended Kalman filter algorithm. Simulations based on actual data are established to verify accuracy and stability in the regression of model parameters. Experiments are also performed to prove that the proposed estimator exhibits good reliability and adaptability under different loading profiles with various temperatures. In addition, open-circuit voltage (OCV is used to estimate SOC in the proposed algorithm. However, the OCV based on the proposed online identification includes a part of concentration polarization and hysteresis, which is defined as parametric identification-based OCV (OCVPI. Considering the temperature factor, a novel OCV–SOC relationship map is established by using OCVPI under various temperatures. Finally, a validating experiment is conducted based on the consecutive loading profiles. Results indicate that our method is effective and adaptable when a battery operates at different ambient temperatures.

  11. Det Ambiente

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Det ambiente er iscenesættelsen af en karakteristisk sanseoplevelse, der er kendetegnet ved fornemmelsen af at være omgivet. I dag bliver begrebet om det ambiente mest anvendt i forbindelse med musikgenren ’ambient musik’. Det ambiente er dog ikke essentielt knyttet til det musikalske, men må...... forstås som et betydeligt bredere fænomen i den moderne æstetiske kultur, der spiller en væsentlig rolle i oplevelsen af moderne transportformer, arkitektur, film, lydkunst, installationskunst og digitale multimedieiscenesættelser. En forståelse af det ambiente er derfor centralt for forståelsen af en...... moderne æstetiseret oplevelseskultur i almindelighed. Da det ambiente ikke hidtil har været gjort til genstand for en mere indgående teoretisk behandling, er der dog stor usikkerhed omkring, hvad fænomenet overhovedet indebærer. Hovedformålet med Det ambiente – Sansning, medialisering, omgivelse er derfor...

  12. Room temperature synthesis of water-repellent polystyrene nanocomposite coating

    Energy Technology Data Exchange (ETDEWEB)

    Guo Yonggang; Jiang Dong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Zhang Xia; Zhang Zhijun [Laboratory of Special Functional Materials, Henan University, Kaifeng 475001 (China); Wang Qihua, E-mail: wangqh@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2010-09-15

    A stable superhydrophobic polystyrene nanocomposite coating was fabricated by means of a very simple and easy method. The coating was characterized by scanning electron microscopy and X-ray photoelectron spectrum. The wettability of the products was also investigated. By adding the surface-modified SiO{sub 2} nanoparticles, the wettability of the coating changed to water-repellent superhydrophobic, not only for pure water, but also for a wide pH range of corrosive liquids. The influence of the drying temperature and SiO{sub 2} content on the wettability of the nanocomposite coating was also investigated. It was found that both factors had little or no significant effect on the wetting behavior of the coating surface.

  13. A practical synthesis of 3,4-diethoxybenzthioamide based on Friedel-Crafts reaction with potassium thiocyanate in methanesulfonic acid.

    Science.gov (United States)

    Aki, Shinji; Fujioka, Takafumi; Ishigami, Masashi; Minamikawa, Jun-ichi

    2002-09-01

    The synthesis of 3,4-diethoxybenzthioamide, the key intermediate for OPC-6535, is achieved by employing Friedel-Crafts reaction of 1,2-diethoxybenzene with potassium thiocyanate in methanesulfonic acid at ambient temperature.

  14. High-Temperature Microfluidic Synthesis of CdSe Nanocrystals inNanoliter Droplets

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Emory M.; Alivisatos, A. Paul; Mathies, Richard A.

    2005-06-09

    The high-temperature synthesis of CdSe nanocrystals innanoliter-volume droplets flowing in a perfluorinated carrier fluidthrough a microfabricated reactor is presented. A flow-focusing nanojetstructure with a step increase in channel height reproducibly generatedoctadecene droplets in Fomblin Y 06/6 perfluorinated polyether atcapillary numbers up to 0.81 and with a droplet:carrier fluid viscosityratio of 0.035. Cadmium and selenium precursors flowing in octadecenedroplets through a high-temperature (240-300 degrees C) glassmicroreactor produced high quality CdSe nanocrystals, as verified byoptical spectroscopy and transmission electron microscopy. Isolating thereaction solution in droplets prevented particle deposition andhydrodynamic dispersion, allowing the reproducible synthesis ofnanocrystals at three different temperatures and four different residencetimes in the span of four hours. Our synthesis of a wide range ofnanocrystals at high temperatures, high capillary numbers, and lowviscosity ratio illustrates the general utility of droplet-basedmicrofluidic reactors to encapsulate nanoliter volumes of organic oraqueous solutions and to precisely control chemical or biochemicalreactions.

  15. X-ray sensing materials stability: influence of ambient storage temperature on essential thermal properties of undoped vitreous selenium

    Science.gov (United States)

    Tonchev, D.; Mani, H.; Belev, G.; Kostova, I.; Kasap, S.

    2014-12-01

    Amorphous selenium (a-Se) is currently used in x-ray image detectors as an x-ray photoconductor. Normally a-Se films used in device applications are fabricated by the evaporation of vitreous bulk material loaded into boats in a typical vacuum deposition system. The resistance against crystallization is an important factor in both film and bulk forms of a-Se. Previous work has indicted that the resistance to crystallization is surprisingly more pronounced around 35 °C [1]. In this work we have therefore examined the essential thermal properties of vitreous selenium (99.999%) samples that have been stored at different temperatures. The thermal characterization experiments involved a series of DSC (Differential Scanning Calorimetry) measurements in which have monitored the glass transition and melting endotherms, and the crystallization exotherm in heating-cooling-heating scans. In DSC experiments, a sample would be heated to a temperature above the melting temperature, equilibrated, then cooled at a fixed rate down to 20 °C, then equilibrated and finally scanned again under a heating schedule. The samples were isothermally stored at temperatures corresponding to 18, 35 and 55 °C. The thermal analysis results show that there are distinct differences in the thermal properties. We have examined the stability in terms of the difference in the crystallization onset temperature (Tc) and the onset of glass transition temperature (Tg). We also examined the Hruby coefficient (Kgl) of these samples, that is Kgl = (Tc - Tg)/(Tm - Tc) where Tc is the crystallization onset temperature and Tm is the melting onset temperature. We have found Kgl to depend on the storage temperature. Surprisingly, we observed that the Hruby coefficient is actually larger at 35 °C compared to the values at 18 and 55 °C.

  16. The effect of irradiation temperatures between ambient and 80 deg. C on the response of alanine dosimeters

    DEFF Research Database (Denmark)

    Sharpe, P.H.G.; Miller, Arne; Sephton, J.P.;

    2009-01-01

    Published data on the effect of irradiation temperature on the response of alanine dosimeters does not extend to the temperatures that may be experienced in high-dose industrial irradiations, particularly in the case of electron beams. We describe here results of the irradiation of alanine...... begins to deviate significantly from linearity and shows marked dose dependence. The effect of this behaviour under conditions typically experienced in industrial processing is evaluated and recommendations made concerning the use of alanine dosimeters at high doses and temperatures....

  17. Separation of p-divinylbenzene by selective room-temperature adsorption inside Mg-CUK-1 prepared by aqueous microwave synthesis.

    Science.gov (United States)

    Saccoccia, Beau; Bohnsack, Alisha M; Waggoner, Nolan W; Cho, Kyung Ho; Lee, Ji Sun; Hong, Do-Young; Lynch, Vincent M; Chang, Jong-San; Humphrey, Simon M

    2015-04-27

    A new Mg(II) -based version of the porous coordination polymer CUK-1 with one-dimensional pore structure was prepared by microwave synthesis in water. Mg-CUK-1 is moisture-stable, thermally stable up to 500 °C, and shows unusual reversible soft-crystal behavior: dehydrated single crystals of the material selectively adsorb a range of organic molecules at ambient temperature and pressure. Both polar and apolar aromatic compounds, including pyridine, benzene, p-xylene, and p-divinylbenzene (p-DVB), are all readily adsorbed, while other isomers from complex mixtures of xylenes or DVBs are selectively excluded. The solvent-loaded structures have been studied by single-crystal X-ray diffraction. Time-dependent liquid sorption experiments using commercially available DVB demonstrate a high and rapid selective adsorption of p-DVB and exclusion of m-DVB and ethylvinylbenzene isomers.

  18. DOE STI Product/Final Report Number 3 Electrochemical Investigation of Novel Electrolytes for Ambient Temperature Sodium Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ketack; Lang, Christopher M.; Doyle, Kevin; Kohl, Paul A.

    2005-12-01

    The need for low-cost, high-energy density, durable, secondary batteries continues to rise with the demands of the electronics and automobile industries. A room-temperature version of the (high-temperature) ''Zebra Cell'' may provide an interesting technology for portable electronics and transportation. Sodium-based batteries have received attention as an alternative to the lithium-based batteries due to several factors including the absence of dendrite formation during sodium deposition and the abundance of sodium. This work focused on (1) the development of room-temperature ionic liquids (IL) for use in electrochemical devices, including batteries, (2) development and evaluation of secondary sodium batteries using room-temperature ILs, and (3) advancing the fundamental understanding of the electrochemical processes involving ILs and battery technology. Several objectives were accomplished during this program.

  19. Multiplexed Sensor for Synthesis Gas Compsition and Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Steven Buckley; Reza Gharavi; Marco Leon

    2007-10-01

    The overall goal of this project has been to develop a highly sensitive, multiplexed TDL-based sensor for CO{sub 2}, CO, H{sub 2}O (and temperature), CH{sub 4}, H{sub 2}S, and NH{sub 3}. Such a sensor was designed with so-called 'plug-and-play' characteristics to accommodate additional sensors, and provided in situ path-integrated measurements indicative of average concentrations at speeds suitable for direct gasifier control. The project developed the sensor and culminated in a real-world test of the underlying technology behind the sensor. During the project, new underlying measurements of spectroscopic constants for all of the gases of interest performed, in custom cells built for the project. The envisioned instrument was built from scratch from component lasers, fiber optics, amplifier blocks, detectors, etc. The sensor was tested for nearly a week in an operational power plant. The products of this research are expected to have a direct impact on gasifier technology and the production of high-quality syngas, with substantial broader application to coal and other energy systems. This report is the final technical report on project DE-FG26-04NT42172. During the project we completed all of the milestones planned in the project, with a modification of milestone (7) required due to lack of funding and personnel.

  20. Response of branchial Na(+)/K(+) ATPase to changes in ambient temperature in Atlantic cod (Gadus morhua) and whiting (Merlangius merlangus).

    Science.gov (United States)

    Michael, Katharina; Koschnick, Nils; Pörtner, Hans-O; Lucassen, Magnus

    2016-05-01

    The maintenance of ion and pH homeostasis despite changes in ambient temperature is crucial for ectothermic organisms. Thermal sensitivity of Na(+)/K(+) ATPase mRNA expression, protein expression and activity was determined in gills of North Sea cod (NC) and Northeastern Arctic cod (NEAC), acclimated for 6 weeks at 4 and 10 °C and compared to field samples of North Sea cod (sNC), acclimatized to early spring (4 °C) and summer (18 °C) conditions. The same analyses were conducted in gills of the confamiliar whiting, acclimated at 4 and 10 °C. Branchial Na(+)/K(+) ATPase capacities remained uncompensated at functional and protein levels in NC and NEAC at both acclimation temperatures. Na(+)/K(+) ATPase mRNA expression in NEAC acclimated at 10 °C was about twofold higher compared to NC, indicating some population-specific differentiation at this level. Lower Na(+)/K(+) ATPase capacities in gills of warm-acclimatized sNC at common assay temperatures indicate thermal compensation between seasonal extremes, and post-translational modifications contributed to this mitigation at high assay temperature. Together, cod compensates Na(+)/K(+) ATPase capacities on the warm edge of the thermal window and below 4 °C, respectively. In contrast, whiting Na(+)/K(+) ATPase capacities were cold compensated at 4 °C, supported by 1.5-fold higher mRNA and protein expression. Besides, capacities were lower in whiting compared to NC and NEAC at optimum temperature, which may be advantageous in terms of reduced maintenance cost, but at temperatures ≤4 °C, compensation may represent an energy trade-off to maintain homeostasis. The species-specific response of gadid Na(+)/K(+) ATPase indicates certain threshold temperatures beyond which compensation of the pump is elicited, possibly related to the different biogeography of these species.

  1. Changes in ambient temperature and oxygenation during the proestrus do not affect duration, regularity and repeatability of the estrus cycle in female rats.

    Directory of Open Access Journals (Sweden)

    Grazyna Wójcik

    2009-12-01

    Full Text Available There are a lot of factors affecting the release of hormones from the anterior part of pituitary gland and their interactions with other parts of the endocrine, nervous and immune systems. The special significance of the proestrus phase of the estrous cycle of the rat, during which LH and FSH levels increase, followed by ovulation is known. The short length of the estrous cycle and the well recognized sequence of vaginal lavage cytology make it useful for investigating the influence of a stressful environment on the reproductive function. Short duration and mild changes in environmental conditions is considered as a factor analogous to psychological stress. The study was undertaken to determine the effects of a short duration change in the ambient temperature and oxygenation (30 minutes on the proestrus phase of reproductive cycle and on the repeatability and regularity of phases of the reproductive cycle of Wistar strain rats. The animals were kept under standard conditions and had food and water available ad libitum. The climatic chamber with automatically adjustable and monitored internal parameters (temperature, oxygenation, humidity was used to develop stress conditions. An estimation of the vaginal lavage using the microscope was done to determine the estrous cycle. The animals were divided into 6 groups. On the day of experiment: the control group (CG stayed in the climatic chamber for 30 minutes (ambient temperature 21 degrees C, normoxia - 21% O(2, the five test groups (TG - I - V remained in the climatic chamber for 30 minutes, in the established environmental conditions (I - 21 degrees C, 10% O(2; II - 10 degrees C, 21% O(2; III - 10 degrees C, 10% O(2; IV - 35 degrees C, 21% O(2; V - 35 degrees C, 10% O(2. During the following days after the experiment, a microscopic estimation of vaginal lavage was collected over again. There were no changes of duration and sequence of the present estrous cycle and repeatability of the next cycles

  2. Ambient surfactantless synthesis, growth mechanism, and size-dependent electrocatalytic behavior of high-quality, single crystalline palladium nanowires.

    Science.gov (United States)

    Koenigsmann, Christopher; Santulli, Alexander C; Sutter, Eli; Wong, Stanislaus S

    2011-09-27

    In this report, we utilize the U-tube double diffusion device as a reliable, environmentally friendly method for the size-controlled synthesis of high-quality, single crystalline Pd nanowires. The nanowires grown in 200 and 15 nm polycarbonate template pores maintain diameters of 270 ± 45 nm and 45 ± 9 nm, respectively, and could be isolated either as individual nanowires or as ordered free-standing arrays. The growth mechanism of these nanowires has been extensively explored, and we have carried out characterization of the isolated nanowires, free-standing nanowire arrays, and cross sections of the filled template in order to determine that a unique two-step growth process predominates within the template pores. Moreover, as-prepared submicrometer and nanosized wires were studied by comparison with ultrathin 2 nm Pd nanowires in order to elucidate the size-dependent trend in oxygen reduction reaction (ORR) electrocatalysis. Subsequently, the desired platinum monolayer overcoating was reliably deposited onto the surface of the Pd nanowires by Cu underpotential deposition (UPD) followed by galvanic displacement of the Cu adatoms. The specific and platinum mass activity of the core-shell catalysts was found to increase from 0.40 mA/cm(2) and 1.01 A/mg to 0.74 mA/cm(2) and 1.74 A/mg as the diameter was decreased from the submicrometer size regime to the ultrathin nanometer range.

  3. Axial- and radial-resolved electron density and excitation temperature of aluminum plasma induced by nanosecond laser: Effect of the ambient gas composition and pressure

    Directory of Open Access Journals (Sweden)

    Mahmoud S. Dawood

    2015-11-01

    Full Text Available The spatial variation of the characteristics of an aluminum plasma induced by a pulsed nanosecond XeCl laser is studied in this paper. The electron density and the excitation temperature are deduced from time- and space- resolved Stark broadening of an ion line and from a Boltzmann diagram, respectively. The influence of the gas pressure (from vacuum up to atmospheric pressure and compositions (argon, nitrogen and helium on these characteristics is investigated. It is observed that the highest electron density occurs near the laser spot and decreases by moving away both from the target surface and from the plume center to its edge. The electron density increases with the gas pressure, the highest values being occurred at atmospheric pressure when the ambient gas has the highest mass, i.e. in argon. The excitation temperature is determined from the Boltzmann plot of line intensities of iron impurities present in the aluminum target. The highest temperature is observed close to the laser spot location for argon at atmospheric pressure. It decreases by moving away from the target surface in the axial direction. However, no significant variation of temperature occurs along the radial direction. The differences observed between the axial and radial direction are mainly due to the different plasma kinetics in both directions.

  4. The effect of temperature in flux-assisted synthesis of SnNb2O6

    KAUST Repository

    Noureldine, Dalal

    2014-10-03

    A flux-assisted method was used to synthesize SnNb2O6 as a visible-light-responsive metal oxide photocatalyst. The role of synthesis temperature was investigated in detail using different reaction temperatures (300, 500, 600, 800, 1000 °C). The obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET). The synthesis with SnCl2 as a flux led to tin niobate particles in the platelet morphology with smooth surfaces. The synthesized crystal showed 2D anisotropic growth along the (600) plane as the flux ratio increased. The particles synthesized with a high reactant to flux ratio (1:10 or higher) exhibited improved photocatalytic activity for hydrogen evolution from an aqueous methanol solution under visible radiation (λ > 420 nm). © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  5. Room temperature synthesis of water repellent silica coatings by the dip coat technique

    Science.gov (United States)

    Bhagat, Sharad D.; Kim, Yong-Ha; Ahn, Young-Soo

    2006-12-01

    The present paper describes the room temperature synthesis of dip coated water repellent silica coatings onto stainless steel substrates using 1,1,1,3,3,3-hexamethyldisilazane as a surface modifying agent. The hydrophobic property of the silica coating was enhanced by increasing its surface roughness, which was achieved by a proper control over the MeOH/TMOS molar ratio ( S) during the synthesis. The contact angle of a water droplet (10 μl) increased from 72° to 145° with an increase in the S value from 9.1 to 36.4. The silica coating showed a minimum sliding angle of 15° for a water droplet of 10 μl. The water repellent silica coatings are thermally stable up to a temperature of 340 °C. The results have been discussed by taking into consideration the contact angle measurements, surface morphology and sol-gel parameters.

  6. Combustion synthesis and structural analysis of nanocrystalline nickel ferrite at low temperature regime

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugavel, T., E-mail: gokulrajs@hotmail.com, E-mail: shanmugavelnano@gmail.com [Department of Physics, Anna University of Technology, Coimbatore-641 047 (India); Raj, S. Gokul, E-mail: gokulrajs@hotmail.com, E-mail: shanmugavelnano@gmail.com [Department of Physics, Vel tech University, Avadi, Chennai-600062 India (India); Rajarajan, G. [Department of Physics, Selvam College of Technology, Namakkal-637005 India (India); Kumar, G. Ramesh [Department of Physics, University College of Engineering, Anna University Chennai, Arni 632317 (India); Boopathi, G. [Department of Physics, Presidency College (Autonomous), Chennai - 600005 (India)

    2015-06-24

    Combustion synthesis of single phase Nickel ferrite was successfully achieved at low temperature regime. The obtained powders were calcinated to increase the crystallinity and their characterization change due to calcinations is investigated in detail. Citric acid used as a chelating agent for the synthesis of nickel ferrite. Pure single phase nickel ferrites were found at this low temperature. The average crystalline sizes were measured by using powder XRD measurements. Surface morphology was investigated through Transmission Electron Microscope (TEM). Particle size calculated in XRD is compared with TEM results. Magnetic behaviour of the samples is analyzed by using Vibrating Sample Magnetometer (VSM). Saturation magnetization, coercivity and retentivity are measured and their results are discussed in detail.

  7. Influence of Plasma Jet Temperature Profiles in Arc Discharge Methods of Carbon Nanotubes Synthesis

    Directory of Open Access Journals (Sweden)

    Grzegorz Raniszewski

    2017-02-01

    Full Text Available One of the most common methods of carbon nanotubes (CNTs synthesis is application of an electric-arc plasma. However, the final product in the form of cathode deposit is composed of carbon nanotubes and a variety of carbon impurities. An assay of carbon nanotubes produced in arc discharge systems available on the market shows that commercial cathode deposits contain about 10% CNTs. Given that the quality of the final product depends on carbon–plasma jet parameters, it is possible to increase the yield of the synthesis by plasma jet control. Most of the carbon nanotubes are multiwall carbon nanotubes (MWCNTs. It was observed that the addition of catalysts significantly changes the plasma composition, effective ionization potential, the arc channel conductance, and in effect temperature of the arc and carbon elements flux. This paper focuses on the influence of metal components on plasma-jet forming containing carbon nanotubes cathode deposit. The plasma jet temperature control system is presented.

  8. Low Temperature Synthesis of Rutile TiO2 Nanocrystals and Their Photovoltaic and Photocatalytic Properties.

    Science.gov (United States)

    Roy, Subhasis; Han, Gill Sang; Shin, Hyunjung; Lee, Jin Wook; Mun, Jinsoo; Shin, Hyunho; Jung, Hyun Suk

    2015-06-01

    We report a novel method of synthesizing rutile TiO2 nanocrystals at low temperature (200 degrees C) via a butanol rinsing process followed by heat treatment in an O2 atmosphere. The rutile nanocrystals show uniform size distribution of approximately 20 nm and good crystallinity confirmed by X-ray diffraction and transmission electron microscopy. A mechanism for the low temperature synthesis of rutile nanocrystals is rationalized in terms of an explosive thermal decomposition reaction of butoxy groups on TiO2 powders with O2 gas. Characterizations of the photovoltaic and photocatalytic properties of rutile nanocrystals exhibited higher photoactivity than large-sized conventional rutile powder, which demonstrates that this novel synthesis technology could expand applications of rutile powders to various photoactive devices beyond solar cells and photocatalysts.

  9. On the Effect of Carbon Content to the Mechanical Properties and Microstructure of Green Compacts Formed at above Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Md. Mujibur Rahman

    2011-01-01

    Full Text Available Friction force is generated during the generation of green compacts from metal powder, which obviously gives adverse effect to the mechanical properties and microstructure of the green compacts. In this study, fine carbon powder is used to minimize the interparticle as well as die wall frictions and as alloying element hence high density yet defect-free near-net shape or net shape mechanical components can be produced. Powder forming at elevated temperature is a relatively new technology hence the effect of carbon content is not fully explored yet. Therefore, a lab scale warm compaction rig is designed and fabricated which enabled the generation of green compacts at different forming load and temperature. The powder mass was prepared by mechanically mixing iron ASC 100.29 powder with different weight percent of fine carbon powder for different duration of time. The prepared powder mass was formed at different compaction temperature to generate green compacts for the purpose of mechanical testing and microstructure evaluation. The results revealed that the mechanical properties and microstructures of green compacts are affected by the carbon content, mixing time, as well as forming temperature. From this study, the suitable carbon content, mixing time, and forming temperature are identified for the production of high quality mechanical components.

  10. The Aluminum Based Composite Produced by Self Propagating High Temperature Synthesis

    Directory of Open Access Journals (Sweden)

    Agus PRAMONO

    2016-05-01

    Full Text Available Self-propagating high-temperature synthesis method can be used for producing aluminum and boron carbide based composites. The experimental composites were fabricated using cobalt and carbon as catalysts. The microstructure of the material was studied using Scanning Electron Microscopy and the mechanical properties were determined using micro-hardness testing. Al/B4C based composites with improved properties were obtained and the role of Co/C catalysts was studied.

  11. Cross-sensitivity of metal oxide gas sensor to ambient temperature and humidity: Effects on gas distribution mapping

    Science.gov (United States)

    Kamarudin, K.; Bennetts, V. H.; Mamduh, S. M.; Visvanathan, R.; Yeon, A. S. A.; Shakaff, A. Y. M.; Zakaria, A.; Abdullah, A. H.; Kamarudin, L. M.

    2017-03-01

    Metal oxide gas sensors have been widely used in robotics application to perform remote and mobile gas sensing. However, previous researches have indicated that this type of sensor technology is cross-sensitive to environmental temperature and humidity. This paper therefore investigates the effects of these two factors towards gas distribution mapping and gas source localization domains. A mobile robot equipped with TGS2600 gas sensor was deployed to build gas distribution maps of indoor environment, where the temperature and humidity varies. The results from the trials in environment with and without gas source indicated that there is a strong relation between the fluctuation of the mean and variance map with respect to the variations in the temperature and humidity maps.

  12. Mathematical modeling of heat shock protein synthesis in response to temperature change.

    Science.gov (United States)

    Szymańska, Zuzanna; Zylicz, Maciej

    2009-08-07

    One of the most important questions in cell biology is how cells cope with rapid changes in their environment. The range of common molecular responses includes a dramatic change in the pattern of gene expression and the elevated synthesis of so-called heat shock (or stress) proteins (HSPs). Induction of HSPs increases cell survival under stress conditions [Morimoto, R.I., 1993. Cells in stress: transcriptional activation of heat shock genes. Science 259, 1409-1410]. In this paper we propose a mathematical model of heat shock protein synthesis induced by an external temperature stimulus. Our model consists of a system of nine nonlinear ordinary differential equations describing the temporal evolution of the key variables involved in the regulation of HSP synthesis. Computational simulations of our model are carried out for different external temperature stimuli. We compare our model predictions with experimental data for three different cases-one corresponding to heat shock, the second corresponding to slow heating conditions and the third corresponding to a short heat shock (lasting about 40 min). We also present our model predictions for heat shocks carried out up to different final temperatures and finally we present a new hypothesis concerning the molecular response to stress that explains some phenomena observed in experiments.

  13. Exploration of the role of anions in the synthesis of Cr containing mesoporous materials at room temperature

    NARCIS (Netherlands)

    Mahony, L; Wu, C.M.; Kibombo, H.S.; Thiruppathi, E.; Baltrusaitis, J.; Rasalingam, S; Koodali, R.T.

    2013-01-01

    Chromium containing mesoporous silica materials were synthesized via a modified Stöber synthesis at room temperature. The chromium ion loading and the effect of counter ion in the synthesis were studied in detail. The mesoporous materials were extensively characterized by powder X-ray diffraction (X

  14. Synthesis of lipase-catalysed silicone-polyesters and silicone-polyamides at elevated temperatures.

    Science.gov (United States)

    Frampton, Mark B; Zelisko, Paul M

    2013-10-18

    More and more enzymes are being explored as alternatives to conventional catalysts in chemical reactions. To utilize these biocatalysts to their fullest, it is incumbent on researchers to gain a complete understanding of the reaction conditions that particular enzymes will tolerate. To this end siloxane-containing polyesters and polyamides have been produced via N435-mediated catalysis at temperatures well above the normal denaturation temperature for free CalB. Low molecular weight disiloxane-based acceptors release the enzyme from its acylated state with equal proficiency while longer chain siloxanes favours polyester synthesis. The thermal tolerance of the enzyme catalyst is increased using longer chain diesters and generally more hydrophobic substrates.

  15. Modulation of ambient temperature promotes inflammation and initiates atherosclerosis in wild type C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Daniel A. Giles

    2016-11-01

    Conclusions: In sum, our novel data in WT C57Bl/6 mice suggest that modulation of a single environmental variable, temperature, dramatically alters mouse physiology, metabolism, and inflammation, allowing for an improved mouse model of atherosclerosis. Thus, thermoneutral housing of mice shows promise in yielding a better understanding of the cellular and molecular pathways underlying the pathogenesis of diverse diseases.

  16. High-T(sub c) Superconductor-Normal-Superconductor Junctions with Polyimide-Passivated Ambient Temperature Edge Formation

    Science.gov (United States)

    Barner, J. B.; Kleinsasser, A. W.; Hunt, B. D.

    1996-01-01

    The ability to controllably fabricate High-Temperature Superconductor (HTS) S-Normal-S (SNS) Josephson Juntions (JJ's) enhances the possibilities fro many applications, including digital circuits, SQUID's, and mixers. A wide variety of approaches to fabricating SNS-like junctions has been tried and analyzed in terms of proximity effect behavior.

  17. Effects of relative humidity and ambient temperature on the ballistic delivery of micro-particles to excised porcine skin.

    Science.gov (United States)

    Kendall, Mark; Rishworth, Stephen; Carter, Fiona; Mitchell, Thomas

    2004-03-01

    The effectiveness of ballistic particle delivery to the skin is often dependent upon breaching the stratum corneum (SC) and targeting cells within defined layers of the viable epidermis. This paper experimentally determines the influence of relative humidity (RH) and temperature on the ballistic delivery of particles to the skin. Gold particles of radius 0.9+/-0.6 microm were accelerated by a hand-held supersonic device to impact freshly excised porcine skin at 410-665 m per s. Increasing the RH from 15% to 95% (temperature at 25 degrees C) led to a particle penetration increase by a factor of 1.8. Temperature increases from 20 degrees C to 40 degrees C (RH at 15%) enhanced particle penetration 2-fold. In both cases, these increases were sufficient to move the target layer from the SC to the viable epidermis. Relative trends in particle penetration compared well with predictions from a theoretical model well. Calculated absolute penetration depths are 6-fold greater than the measurements. The inversely calculated dynamic yield stress of the SC is up to a factor of 10 higher than reported quasi-static measurements, due to changes in tissue failure modes over a strain-rate range spanning 10 orders of magnitude. If targeted particle delivery is required, it is recommended that the environmental RH and temperature be monitored.

  18. The Combined Effect of High Ambient Temperature and Antihypertensive Treatment on Renal Function in Hospitalized Elderly Patients

    Science.gov (United States)

    Novack, Victor; Rogachev, Boris; Haviv, Yosef S.; Barski, Leonid

    2016-01-01

    Background The aging kidney manifests structural, functional as well as pharmacological changes, rendering elderly patients more susceptible to adverse environmental influences on their health, dehydration in particular. Hypothesis Higher temperature is associated with renal function impairment in patients 65 years and older who routinely take thiazide and/or ACE-inhibitors/ARBs. Methods We obtained health data of patients older than 65 who were admitted to a large tertiary center during the years 2006–2011, with a previous diagnosis of hypertension, and treated with thiazide, ACE-inhibitors/ARBs or both. We collected environmental data of daily temperature, available from collaborative public and governmental institutions. In order to estimate the effect of daily temperature on renal function we performed linear mixed models, separately for each treatment group and creatinine change during hospital admission. Results We identified 26,286 admissions for 14, 268 patients with a mean age of 75.6 (±6.9) years, of whom 53.6% were men. Increment in daily temperature on admission of 5°C had significant effect on creatinine increase in the no treatment (baseline creatinine adjusted 0.824 mg/dL, % change 1.212, % change 95% C.I 0.082–2.354) and dual treatment groups (baseline creatinine adjusted 1.032mg/dL, % change 3.440, % change 95% C.I 1.227–5.700). Sub-analysis stratified by advanced age, chronic kidney disease and primary diagnosis on hospital admission, revealed a significant association within patients admitted due to acute infection and treated with dual therapy. Conclusion Whereas previous studies analyzed sporadic climate effects during heat waves and/or excluded older population taking anti-hypertensive medications, the present study is novel by showing a durable association of temperature and decreased renal function specifically in elderly patients taking anti-hypertensive medications. PMID:27992525

  19. Experimental Study of Ambient Air Temperature Effects on The Performance of a General Vapor-Compression Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Ayad T. Mustafa

    2013-05-01

    Full Text Available         In this work an experimental study for the vapor – compression refrigeration cycle has been performed under temperature range of  9.7-32°C. The effect of      varying temperature on heat exchangers pressures, cooling capacity, net power consumption, and coefficient of performance COP are studied .                                   The results indicated that condenser pressure, evaporator pressure, and power consumption increased with the increase of temperature. The data also indicated that cooling capacity increased as temperature increased until 15.6°C then after it decreased with further temperature increase. Also COP follow the same tread of cooling capacity.                                                                                                              

  20. Periodic usage of low-protein methionine-fortified diets in broiler chickens under high ambient temperature conditions: effects on performance, slaughter traits, leukocyte profiles and antibody response.

    Science.gov (United States)

    Ghasemi, Hossein Ali; Ghasemi, Rohollah; Torki, Mehran

    2014-09-01

    This study was performed to evaluate the effects of adding methionine supplements to low-protein diets and subsequent re-feeding with a normal diet on the productive performance, slaughter parameters, leukocyte profiles and antibody response in broiler chickens reared under heat stress conditions.During the whole experimental period (6-49 days), the birds were raised in battery cages located in high ambient temperature in an open-sided housing system. A total of 360 6-day-old male chickens were divided into six treatments in six replicates with ten chicks each. Six isoenergetic diets, with similar total sulfur amino acids levels, were formulated to provide 100 and 100 (control), 85 and 100 (85S), 70 and 100 (70S), 85 and 85 (85SG), 70 and 85 (70S85G), and 70 and 70% (70SG) of National Research Council recommended levels for crude protein during the starter (6-21 day) and grower (22-42 day) periods, respectively. Subsequently, all groups received a diet containing the same nutrients during the finisher period (43-49 day). The results showed that, under heat stress conditions, average daily gain and feed conversion ratio and performance index from day 6 to 49, breast and thigh yields and antibody titer against Newcastle disease in the birds fed diets 85S, 70S and 85SG were similar to those of birds fed control diet, whereas feeding diets 70S85G and 70SG significantly decreased the values of above-mentioned parameters. Additionally, diets 85S, 70S and 85SG significantly decreased mortality rate and heterophil:lymphocyte ratio compared with the control diet. In conclusion, the results indicate that supplementation of methionine to diets 85S, 70S and 85SG, and then re-feeding with a conventional diet is an effective tool to maintain productive performance and to improve health indices and heat resistance in broilers under high ambient temperature conditions.

  1. Periodic usage of low-protein methionine-fortified diets in broiler chickens under high ambient temperature conditions: effects on performance, slaughter traits, leukocyte profiles and antibody response

    Science.gov (United States)

    Ghasemi, Hossein Ali; Ghasemi, Rohollah; Torki, Mehran

    2014-09-01

    This study was performed to evaluate the effects of adding methionine supplements to low-protein diets and subsequent re-feeding with a normal diet on the productive performance, slaughter parameters, leukocyte profiles and antibody response in broiler chickens reared under heat stress conditions. During the whole experimental period (6-49 days), the birds were raised in battery cages located in high ambient temperature in an open-sided housing system. A total of 360 6-day-old male chickens were divided into six treatments in six replicates with ten chicks each. Six isoenergetic diets, with similar total sulfur amino acids levels, were formulated to provide 100 and 100 (control), 85 and 100 (85S), 70 and 100 (70S), 85 and 85 (85SG), 70 and 85 (70S85G), and 70 and 70 % (70SG) of National Research Council recommended levels for crude protein during the starter (6-21 day) and grower (22-42 day) periods, respectively. Subsequently, all groups received a diet containing the same nutrients during the finisher period (43-49 day). The results showed that, under heat stress conditions, average daily gain and feed conversion ratio and performance index from day 6 to 49, breast and thigh yields and antibody titer against Newcastle disease in the birds fed diets 85S, 70S and 85SG were similar to those of birds fed control diet, whereas feeding diets 70S85G and 70SG significantly decreased the values of above-mentioned parameters. Additionally, diets 85S, 70S and 85SG significantly decreased mortality rate and heterophil:lymphocyte ratio compared with the control diet. In conclusion, the results indicate that supplementation of methionine to diets 85S, 70S and 85SG, and then re-feeding with a conventional diet is an effective tool to maintain productive performance and to improve health indices and heat resistance in broilers under high ambient temperature conditions.

  2. Heat effects of ambient apparent temperature on all-cause mortality in Cape Town, Durban and Johannesburg, South Africa: 2006-2010.

    Science.gov (United States)

    Wichmann, Janine

    2017-06-01

    Due to climate change, an increase of 3-4°C in ambient temperature is projected along the South African coast and 6-7°C inland during the next 80years. The objective of this study was to investigate the association between daily ambient apparent temperature (Tapp) and daily all-cause non-accidental mortality (hereafter mortality) in Cape Town, Durban and Johannesburg during a 5-year study period (2006-2010). Susceptibility by sex and age groups (Cape Town, Durban and Johannesburg. A 3.3%, 2.6% and 2.8% increase in mortality per IQR increase in Tapp (lag0-1) was observed in Cape Town, Durban and Johannesburg, respectively above the city-specific thresholds. The elderly were more at risk in Cape Town and Johannesburg. No difference in risk was observed for males and females in the three cities. In the meta-analysis an overall significant increase of 0.9% in mortality per 1°C increase in Tapp (lag0-1) was observed for all age groups combined in the three cities. For the ≥65year group a significant increase of 2.1% in mortality was observed. In conclusion, the risks for all age groups combined and the elderly are similar to those reported in studies from developed and developing countries. The results can be used in present-day early warning systems and in risk assessments to estimate the impact of increased Tapp in the country due to climate change. Future research should investigate the association between Tapp and cause-specific mortality and also morbidity.

  3. Increased upper critical field for nanocrystalline MoN thin films deposited on AlN buffered substrates at ambient temperature

    Science.gov (United States)

    Baskaran, R.; Thanikai Arasu, A. V.; Amaladass, E. P.; Vaidhyanathan, L. S.; Baisnab, D. K.

    2016-05-01

    Molybdenum nitride (MoN) thin films have been deposited using reactive DC magnetron sputtering on aluminum nitride buffered oxidized silicon substrates at ambient temperature. GIXRD of aluminum nitride (AlN) deposited under similar conditions has revealed the formation of wurtzite phase AlN. GIXRD characterization of molybdenum thin films deposited on AlN buffered oxidized silicon substrates has indicated the formation of nanocrystalline MoN thin films. The electrical resistivity measurements indicate MoN thin films have a superconducting transition temperature of ~8 K. The minimum transition width of the MoN thin film is 0.05 K at 0 T. The inferred upper critical field B c2(0) for these nanocrystalline MoN thin films obtained by fitting the temperature dependence of critical field with Werthamer, Helfand and Hohenberg theory lies in the range of 17-18 T which is the highest reported in literature for MoN thin films.

  4. On the Effect of Carbon Content to the Mechanical Properties and Microstructure of Green Compacts Formed at above Ambient Temperature

    OpenAIRE

    Md. Mujibur Rahman; Sany Shahriman Md Nor; Hendri Yani Rahman

    2011-01-01

    Friction force is generated during the generation of green compacts from metal powder, which obviously gives adverse effect to the mechanical properties and microstructure of the green compacts. In this study, fine carbon powder is used to minimize the interparticle as well as die wall frictions and as alloying element hence high density yet defect-free near-net shape or net shape mechanical components can be produced. Powder forming at elevated temperature is a relatively new technology henc...

  5. Design and construction of a heat stage for investigations of samples by atomic force microscopy above ambient temperatures

    DEFF Research Database (Denmark)

    Bækmark, Thomas Rosleff; Bjørnholm, Thomas; Mouritsen, Ole G.

    1997-01-01

    The construction from simple and cheap commercially available parts of a miniature heat stage for the direct heating of samples studied with a commercially available optical-lever-detection atomic force microscope is reported. We demonstrate that by using this heat stage, atomic resolution can be...... be obtained on highly oriented pyrolytic graphite at 52 °C. The heat stage is of potential use for the investigation of biological material at physiological temperatures. ©1997 American Institute of Physics....

  6. Modificações nas atividades da poligalacturonase e pectinametilesterase em morangos armazenados a temperatura ambiente Modifications in the activities of poligalacturonase and pectinametilesterase in stored strawberries the ambient temperature

    Directory of Open Access Journals (Sweden)

    Polyanna Alves Silva

    2009-01-01

    Full Text Available Objetivou-se, neste trabalho, avaliar as modificações da poligalacturonase (PG e da pectinametilesterase (PME em morangos cultivados na região de Lavras, MG, e armazenados em temperatura ambiente. Foram utilizados morangos das cultivares 'Oso-grande', 'Toyorrinho' e 'Tudla'. Utilizou-se o delineamento inteiramente casualizado com 4 repetições, sendo os tratamentos arranjados em esquema fatorial (3X2, sendo 3 cultivares e 2 dias de análises (0 e 5 dias. A parcela experimental foi constituída por 10 frutos. Durante o armazenamento houve uma diminuição nos teores de pectina total e um aumento nos de pectina solúvel em todas as variedades analisadas. A atividade da PG e PME aumentaram com o período de armazenamento, independente da cultivar.The objective of this research was to evaluate the modifications of the polygalacturonase (PG and the pectinmethilesterase (PME in strawberries cultivated in the region of Lavras, MG, and stored at room temperature. Strawberries of the research were used for plantation of 'Oso-grande', 'Toyorrinho' and 'Tudla'. The entirely randomized design with 4 replicates was used, being the treatments arranged in factorial (3x2, being 3 plantations and 2 days of analyses (0 and 5 days. The experimental parcel was consisted by 10 fruits. During the storage there was a reduction in the levels of total pectin and an increase in the ones of soluble pectin in all the analyzed varieties. With the period of storage the PG and PME activity grew, independent of the cultivar.

  7. Optimization of synthesis of upconversion luminescence material NaYF4:Er3+,Yb3+ nanometer-phosphor by low-temperature combustion synthesis method

    Institute of Scientific and Technical Information of China (English)

    LU Liping; ZHANG Xiyan

    2013-01-01

    A kind of Er3+-yb3+ co-doped natrium yttrium fluoride nanometer-phosphor sensitive to 980 nm was synthesized by the low-temperature combustion synthesis method,which expanded the application range of the low-temperature combustion synthesis (LCS) method which is always used in the synthesis of oxides and compound oxides.The synthesis conditions were optimized with orthogonal experiments and the optimum technological parameters were obtaincd.Intense upconversion emissions at 522,540 and 653 nm corresponding to the 2H11/2,4S3/2,and 4F9/2 transitions to the 4I15/2 ground state were observed when excited by continuous wavclength (CW) laser radiation at 980 nm.The effect of the carbamide amount on the phase formation and the luminescence intensity was analyzed.The average particle size of the sample was 30-40 nm.

  8. Microwave Assisted Synthesis of Ferrite Nanoparticles: Effect of Reaction Temperature on Particle Size and Magnetic Properties.

    Science.gov (United States)

    Kalyani, S; Sangeetha, J; Philip, John

    2015-08-01

    The preparation of ferrite magnetic nanoparticles of different particle sizes by controlling the reaction temperature using microwave assisted synthesis is reported. The iron oxide nanoparticles synthesized at two different temperatures viz., 45 and 85 °C were characterized using techniques such as X-ray diffraction (XRD), small angle X-ray scattering (SAXS), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The average size of iron oxide nanoparticles synthesized at 45 and 85 °C is found to be 10 and 13.8 nm, respectively, and the nanoparticles exhibited superparamagantic behavior at room temperature. The saturation magnetization values of nanoparticles synthesized at 45 and 85 °C were found to be 67 and 72 emu/g, respectively. The increase in particle size and saturation magnetization values with increase in incubation temperature is attributed to a decrease in supersaturation at elevated temperature. The Curie temperature was found to be 561 and 566 0C for the iron oxide nanoparticles synthesized at 45 and 85 °C, respectively. The FTIR spectrum of the iron oxide nanoparticles synthesized at different temperatures exhibited the characteristic peaks that corresponded to the stretching of bonds between octahedral and tetrahedral metal ions to oxide ions. Our results showed that the ferrite nanoparticle size can be varied by controlling the reaction temperature inside a microwave reactor.

  9. Synthesis of nanocrystalline yttrium iron garnet by low temperature solid state reaction

    Energy Technology Data Exchange (ETDEWEB)

    Yu Hongtao, E-mail: yuhongtao@swust.edu.cn; Zeng Liwen; Lu Chao; Zhang Wenbo; Xu Guangliang

    2011-04-15

    In this work, nanocrystalline yttrium iron garnet powders were produced by low temperature solid state reaction. The phase evolution during the procedure was determined from the thermogravimetric and differential thermal analysis, and the x-ray diffraction patterns. The results of transmission electron microscopy indicated that the prepared powders exhibited grain size at the nano-level of 20 {approx} 40 nm. Dense ceramics with a theoretical density of around 98% were obtained from the prepared powders after sintering at 1280 deg. C, a relative low sintering temperature compared with conventional ceramic processes, and the saturation magnetizations of sintered samples were also determined. - Research Highlights: {yields}No sol or gel form during the synthesis processing using nitrates and citric acid as raw materials. {yields}The synthesis method needs a low heating temperature (700 deg. C) compared with conventional solid state reaction. {yields}The product is a single phase with homogeneous size distribution and nano grains (20 {approx} 40 nm) confirmed by TEM. {yields}Dense YIG ceramic can be sintered at a low temperature (1280 deg. C) compared with that in conventional processing.

  10. Ethylene glycol assisted low-temperature synthesis of boron carbide powder from borate citrate precursors

    Directory of Open Access Journals (Sweden)

    Rafi-ud-din

    2014-09-01

    Full Text Available B4C powders were synthesized by carbothermal reduction of ethylene glycol (EG added borate citrate precursors, and effects of EG additions (0–50 mol% based on citric acid on the morphologies and yields of synthesized B4C powders were investigated. The conditions most suitable for the preparation of precursor were optimized and optimum temperature for precursor formation was 650 °C. EG additions facilitated low-temperature synthesis of B4C at 1350 °C, which was around 100–300 °C lower temperature compared to that without EG additions. The lowering of synthesis temperature was ascribed to the enlargement of interfacial area caused by superior homogeneity and dispersibility of precursors enabling the diffusion of reacting species facile. The 20% EG addition was optimal with free residual carbon lowered to 4%. For smaller EG additions, the polyhedral and rod-like particles of synthesized product co-existed. With higher EG additions, the morphology of synthesized product was transformed into needle and blade-like structure.

  11. Impact of synthesis temperature on hydrogen storage and emission from Ni/Ce composite oxides

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Leung P.; Diamond, Louise; MacDonald, Marion; McMillan, Brian G.; Morrow, James; Spicer, Mark D.; Berlouis, Leonard E.A. [WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL (United Kingdom); Weston, Michael [ITI Energy, The Exchange No.1, 62 Market Street, Aberdeen AB11 5PJ (United Kingdom)

    2009-09-15

    Hydrogen storage and emission from Ni/Ce (0.1:1) composite oxides, prepared by the co-precipitation method at -2 C, 22 C and 60 C using triethylamine as the precipitating agent, are investigated. The as-prepared uncalcined materials exhibit small amounts of H{sub 2} emission even without prior exposure to H{sub 2}, with the amount dependent on the synthesis temperature. Examination of the CO, CO{sub 2} and H{sub 2}O emission profiles suggest a link between the presence and stability of carbonate species within these composite materials and the H{sub 2} emission. Following activation in pure hydrogen at 250 C, all samples show increased H{sub 2} emission levels but it is only in the sample synthesised at 60 C that a simultaneous decrease in the H{sub 2} emission temperature is found. H{sub 2}O emission below 250 C in the activated material indicates that this also originates from hydrogen stored in the material. The activation conditions are shown to have a significant impact on the level of H{sub 2} interaction with these materials. A marked increase of the crystallite size with synthesis temperature, from 1.7 nm at -2 C to 11.7 nm at 60 C, is also found. The difference in of H{sub 2} interaction is associated with a change in the nature/morphology of the materials precipitated at the different temperatures. (author)

  12. Top-down heating for low substrate temperature synthesis of carbon nanotubes.

    Science.gov (United States)

    Chen, G Y; Stolojan, V; Silva, S R P

    2010-06-01

    A top-down heating method to allow for low-temperature large area synthesis of carbon nanotubes using plasma-enhanced chemical vapour deposition is introduced in this paper. The approach utilizes top-down electromagnetic heating rather than conventional heating from a substrate heater under the electrode. A temperature gradient is created between the Ni catalyst surface and the substrate using a metal thermal control barrier layer, on which carbon nanotubes are grown as a function of the bias voltage, hydrocarbon concentrations and growth conditions. The heat during growth is provided by the plasma or energy coupling to the catalyst via top-down heating, which based on the coupled power density and the cooling of the substrate, in addition to the thermal 'barrier layer' properties will dictate the temperature of the growth surface. This unique approach of top-down heating with suitable cooling schemes, coupled with thermal barriers allows for the low substrate temperature synthesis of carbon nanotubes, scalable to large areas.

  13. Continuous low-temperature methanol synthesis from syngas using alcohol promoters

    Energy Technology Data Exchange (ETDEWEB)

    Prasert Reubroycharoen; Tetsuji Yamagami; Tharapong Vitidsant; Yoshiharu Yoneyama; Motoaki Ito; Noritatsu Tsubaki [Toyama University, Toyama (Japan). Department of Material System & Life Science, School of Engineering

    2003-08-01

    Continuous low-temperature methanol synthesis from syngas containing CO{sub 2} on various Cu/ZnO catalysts was investigated by using a semibatch autoclave reactor. Methanol was easily produced at a temperature as low as 443 K and with a pressure of 50 bar with the aid of 2-butanol, which showed a very high efficiency with a one-pass yield of 47.0% and a selectivity of 98.9%. Methanol itself used as alcohol promoter exhibited a higher activity than other 1-alcohols because it has the lowest spatial effect. 2-Alcohols, however, exhibited the highest conversion among the same carbon number because of its well-balanced effects produced by their of electronic and spatial factors. The one-pass conversion was improved by increasing the catalyst weight because no thermodynamic limitations existed at low temperatures. The continuous low-temperature methanol synthesis is a very promising process because completely purified syngas is not necessary. 23 refs., 3 figs., 4 tabs.

  14. Performance of a pilot scale microbial electrolysis cell fed on domestic wastewater at ambient temperatures for a 12 month period.

    Science.gov (United States)

    Heidrich, Elizabeth S; Edwards, Stephen R; Dolfing, Jan; Cotterill, Sarah E; Curtis, Thomas P

    2014-12-01

    A 100-L microbial electrolysis cell (MEC) was operated for a 12-month period fed on raw domestic wastewater at temperatures ranging from 1°C to 22°C, producing an average of 0.6 L/day of hydrogen. Gas production was continuous though decreased with time. An average 48.7% of the electrical energy input was recovered, with a Coulombic efficiency of 41.2%. COD removal was inconsistent and below the standards required. Limitations to the cell design, in particular the poor pumping system and large overpotential account for many of the problems. However these are surmountable hurdles that can be addressed in future cycles of pilot scale research. This research has established that the biological process of an MEC will to work at low temperatures with real wastewater for prolonged periods. Testing and demonstrating the robustness and durability of bioelectrochemical systems far beyond that in any previous study, the prospects for developing MEC at full scale are enhanced.

  15. Influence of Constant High Ambient Temperature on Fat Metabolism of Different Parts in Finishing Pigs%持续高温对育肥猪不同部位脂肪代谢的影响

    Institute of Scientific and Technical Information of China (English)

    吴鑫; 冯京海; 张敏红; 苏红光; 贾安峰

    2015-01-01

    parts. High ambient temperature may influence fat deposition in different parts by regulating the content of LPL in different parts. High ambient temperature depressedde novo fatty acid synthesis in adipose tissues and in the liver. However,β-oxidation of fatty acid in skeletal muscles was also inhibited in the high-temperature environment, which may result in an increased concentration of NEFA in the plasma, and NEFAs were esterified to synthesize VLDLs in the liver, reabsorbed by adipose tissues ultimately. But the mechanism that plasma concentrations of NEFA and VLDL were higher in the high-temperature needs to be further studied.%【目的】研究持续高温对育肥猪脂肪代谢的影响并初步探讨影响的机制。【方法】选用16头(79.6±1.2)kg的健康杜长大阉公猪,随机分为2个处理组,分别饲养于(30±0.5)℃(高温组)和(22±0.5)℃(常温组)的环控舱内,单笼饲养,自由采食和饮水。环控舱内温度在21 d试验期内保持不变,湿度控制在(55±5)%,每天光照14 h,舱内持续均匀通风。试验期满屠宰,宰前12 h禁食,自由饮水。【结果】和常温组相比,高温组育肥猪胴体重和皮下脂肪厚有所降低,但并不显著(P>0.10);与常温组相比,高温组育肥猪背部皮下脂肪占胴体的比例无显著变化(P>0.10),肾周脂肪占胴体的比例有提高趋势(+22.06%;P=0.07),背最长肌(LM)脂质含量有降低趋势(-22.39%;P=0.08),表明持续高温对猪不同部位脂肪沉积的影响存在差异。持续高温显著降低育肥猪背部皮下脂肪和肾周脂肪中苹果酸酶(ME)活性(P<0.05)和脂肪酸合成酶(FAS)活性(P<0.05),显著降低LM中乙酰辅酶A羧化酶(ACC)(P<0.01)和FAS(P<0.05)的含量,显著降低肝脏中FAS活性(P<0.01), FAS、ME 和 ACC 为脂肪酸从头合成过程中的关键酶,上述结果表明,持续高温

  16. Unraveling the complexity of iron oxides at high pressure and temperature: Synthesis of Fe5O6.

    Science.gov (United States)

    Lavina, Barbara; Meng, Yue

    2015-06-01

    The iron-oxygen system is the most important reference of rocks' redox state. Even as minor components, iron oxides can play a critical role in redox equilibria, which affect the speciation of the fluid phases chemical differentiation, melting, and physical properties. Until our recent finding of Fe4O5, iron oxides were assumed to comprise only the polymorphs of FeO, Fe3O4, and Fe2O3. Combining synthesis at high pressure and temperature with microdiffraction mapping, we have identified yet another distinct iron oxide, Fe5O6. The new compound, which has an orthorhombic structure, was obtained in the pressure range from 10 to 20 GPa upon laser heating mixtures of iron and hematite at ~2000 K, and is recoverable to ambient conditions. The high-pressure orthorhombic iron oxides Fe5O6, Fe4O5, and h-Fe3O4 display similar iron coordination geometries and structural arrangements, and indeed exhibit coherent systematic behavior of crystallographic parameters and compressibility. Fe5O6, along with FeO and Fe4O5, is a candidate key minor phase of planetary interiors; as such, it is of major petrological and geochemical importance. We are revealing an unforeseen complexity in the Fe-O system with four different compounds-FeO, Fe5O6, Fe4O5, and h-Fe3O4-in a narrow compositional range (0.75 < Fe/O < 1.0). New, finely spaced oxygen buffers at conditions of the Earth's mantle can be defined.

  17. Origin of low temperature deactivation of Ni5Ga3 nanoparticles as catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Gardini, Diego; Sharafutdinov, Irek; Damsgaard, Christian Danvad

    In an effort to find alternative energy sources capable to compete with fossil fuels, methanol synthesis could represent a realistic solution to store “green” hydrogen produced from electrolysis or photo-induced water splitting. Recently, density functional theory (DFT) calculations [1] proposed Ni......-Ga alloys as active catalysts for methanol production from syngas mixtures and Ni-Ga nanoparticles supported on highly porous silica have been prepared using an incipient wetness impregnation technique from a solution of nickel and gallium nitrates [2]. Tests conducted in a fixed-bed reactor showed...... as catalyst for methanol production. Synthesis, followed by deactivation and a series of regeneration steps at increasing temperature in pure H2 has been carried out in a fixed-bed reactor connected to a gas chromatography system. In each regeneration step, CH4 is generated and the activity of the catalyst...

  18. A review of nanostructured lithium ion battery materials via low temperature synthesis.

    Science.gov (United States)

    Chen, Jiajun

    2013-01-01

    Nanostructured materials afford us new opportunities to improve the current technology for synthesizing Li ion batteries. Generating nanomaterials with new properties via an inexpensive approach offers a tremendous potential for realizing high performance Li-ion batteries. In this review, I mainly summarize some of the recent progress made, and describe the patents awarded on synthesizing nanostructured cathode materials for these batteries via low temperature wet- chemistry methods. From an economical view, such syntheses, especially hydrothermal synthesis, may offer the opportunities for significantly lowering the cost of manufacturing battery materials, while conferring distinct environmental advantages. Recent advances in in-situ (real time) X-ray diffraction for studying hydrothermal synthesis have great potential for bettering the rational design of advanced lithium-electrode materials. The development of this technique also will be discussed.

  19. Production of advanced materials by methods of self-propagating high-temperature synthesis

    CERN Document Server

    Tavadze, Giorgi F

    2013-01-01

    This translation from the original Russian book outlines the production of a variety of materials by methods of self-propagating high-temperature synthesis (SHS). The types of materials discussed include: hard, refractory, corrosion and wear-resistant materials, as well as other advanced and speciality materials. The authors address the issue of optimal parameters for SHS reactions occurring during processes involving a preliminary metallothermic reduction stage, and they calculate this using thermodynamic approaches. In order to confirm the effectiveness of this approach, the authors describe experiments focussing on the synthesis of elemental crysalline boron, boron carbides and nitrides. Other parts of this brief include theoretical and experimental results on single-stage production of hard alloys on the basis of titanium and zirconium borides, as well as macrokinetics of degassing and compaciton of SHS-products.This brief is suitable for academics, as well as those working in industrial manufacturing com...

  20. Effects of ambient temperature on egg and larval development of the invasive emerald ash borer (Coleoptera: Buprestidae): implications for laboratory rearing.

    Science.gov (United States)

    Duan, Jian J; Watt, Tim; Taylor, Phil; Larson, Kristi; Lelito, Jonathan P

    2013-10-01

    The emerald ash borer, Agrilus planipennis Fairmaire, an invasive beetle from Asia causing large scale ash (Fraxinus) mortality in North America, has been extremely difficult to rear in the laboratory because of its long life cycle and cryptic nature of immature stages. This lack of effective laboratory-rearing methods has not only hindered research into its biology and ecology, but also mass production of natural enemies for biological control of this invasive pest. Using sticks from the alternate host plant, Fraxinus uhdei (Wenzig) Lingelsh, we characterized the stage-specific development time and growth rate of both emerald ash borer eggs and larvae at different constant temperatures (12-35 degrees C) for the purpose of developing effective laboratory-rearing methods. Results from our study showed that the median time for egg hatching decreased from 20 d at 20 degrees C to 7 d at 35 degrees C, while no emerald ash borer eggs hatched at 12 degrees C. The developmental time for 50% of emerald ash borer larvae advancing to third, fourth, and J-larval stages at 20 degrees C were 8.3, 9.1, and 12.3 wk, respectively, approximately two times longer than at 30 degrees C for the corresponding instars or stages. In contrast to 30 degrees C, however, the development times of emerald ash borer larvae advancing to later instars (from oviposition) were significantly increased at 35 degrees C, indicating adverse effects of this high temperature. The optimal range of ambient temperature to rear emerald ash borer larvae should be between 25-30 degrees C; however, faster rate of egg and larval development should be expected as temperature increases within this range.

  1. Occurrence of gaseous and particulate polycyclic aromatic hydrocarbons in the urban atmosphere: study of sources and ambient temperature effect on the gas/particle concentration and distribution

    Energy Technology Data Exchange (ETDEWEB)

    Tsapakis, Manolis [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece); Stephanou, Euripides G. [Environmental Chemical Processes Laboratory (ECPL), Department of Chemistry, University of Crete, EL-71409 Heraklion (Greece)]. E-mail: stephanou@chemistry.uoc.gr

    2005-01-01

    The presence of polycyclic aromatic hydrocarbons (PAHs) in an urban region (Heraklion, Greece) and processes that govern their atmospheric fate were studied from November 2000 until February 2002. Sixteen samples were collected, by using an artifact-free sampling device, on a monthly basis and the concentration of PAHs in gas and particulate phase was determined. The most abundant members (gas + particles) were phenanthrene (20.0 {+-} 7.0 ng m{sup -3}), fluoranthene (6.5 {+-} 1.7 ng m{sup -3}), pyrene (6.6 {+-} 2.4 ng m{sup -3}), and chrysene (3.1 {+-} 1.5 ng m{sup -3}). Total concentration (gas + particulate) of PAH ranged from 44.3 to 129.2 ng m{sup -3}, with a mean concentration of 79.3 ng m{sup -3}. Total concentration of PAHs in gas phase ranged from 31.4 to 84.7 ng m{sup -3} with non-observable seasonal variation. Conversely, maximum PAH concentrations in the particulate phase occurred during winter months. Particulate concentration varied from 11.4 to 44.9 ng m{sup -3}, with an average of 25.2 ng m{sup -3}. PAH distribution between gas and particulate phase was in agreement with the sub-cooled vapor pressure. Shift in gas/particle distribution due to difference in ambient temperature elucidated to some extent the seasonal variation of the concentration of PAHs in particles. - Capsule: Ambient PAH partitioning between gas and particle phases vary between compounds and with environmental conditions.

  2. Solid state synthesis and room temperature magnetic properties of iron phosphide nanoparticles

    Science.gov (United States)

    Singh, N.; Khanna, P. K.; Joy, P. A.

    2009-02-01

    Room temperature magnetic properties have been achieved for nano-crystalline iron phosphide synthesized from the direct solid state reaction of iron chloride and tri-octylphosphine (TOP). The magnetization continuously increased with higher magnetic fields, indicating a super-paramagnetic behavior. It is observed that room temperature magnetism is possible for the material showing antiferromagnetic nature at low temperatures. In the present synthesis, TOP acted as a source of phosphorus as well as a surfactant. X-ray diffraction (XRD) studies revealed that the black powder is a mixture of FeP and Fe2P. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed elongated as well spherical particles. Energy dispersion X-ray analysis (EDAX) confirmed a non-stoichiometric iron phosphide. Presence of TOP was confirmed by infra-red (IR) spectroscopy, and thermo-gravimetric analysis (TGA) indicated about 6% wt. loss due to presence of organics.

  3. The facile and low temperature synthesis of nanophase hydroxyapatite crystals using wet chemistry.

    Science.gov (United States)

    Dhand, Vivek; Rhee, K Y; Park, Soo-Jin

    2014-03-01

    A simple and facile wet chemistry route was used to synthesize nanophase hydroxyapatite (HaP) crystals at low temperature. The synthesis was carried out at a pH of 11.0 and at a temperature of 37°C. The resulting samples were washed several times and subjected to further analysis. XRD studies revealed that the HaP crystals were polycrystalline in nature with a crystallite size of ~15-60 ± 5 nm. SEM-EDXA images confirmed the presence of calcium (Ca), phosphorous (P), and oxygen (O) peaks. Likewise, FTIR confirmed the presence of characteristic phosphate and hydroxyl peaks in samples. Lastly, HRTEM images clearly showed distinctive lattice fringes positioned in the 100 and 002 planes. TGA analysis shows that HaP crystals can withstand higher calcination temperatures and are thermally stable.

  4. Ambient intelligence

    OpenAIRE

    Sanders, David; Gegov, Alexander

    2006-01-01

    This paper considers some history and the state of the art of Ambient Intelligence and from that seeks to identify new topics and future work. Ubiquitous computing, communications, human-centric computer interaction, embedded systems, context awareness, adaptive systems and distributed device networks are considered.

  5. Effect of feeding whole linseed as a source of polyunsaturated fatty acids on performance and egg characteristics of laying hens kept at high ambient temperature

    Directory of Open Access Journals (Sweden)

    S Ahmad

    2013-03-01

    Full Text Available The present study was conducted to evaluate the effects of feeding whole linseed on the laying performance and egg characteristics in laying hens kept at high ambient environmental temperatures (average 34 ºC; the diurnal temperature range 26 ºC to 41 ºC. Two hundred and forty 38-wk-old white Leghorn laying hens were fed diets containing 0, 5, 10 or 15% whole linseed (as a source of n-3 polyunsaturated fatty acids for a period of 12 weeks. Egg production was recorded daily, while feed intake and egg characteristics were monitored on weekly basis. The results of the study demonstrated that egg production and feed intake decreased, while feed conversion ratio (FCR per dozen of eggs increased (p 0.05 by linseed levels in the diets offered to the laying hens. The results of the present trial suggest that feeding linseed to the laying hens in hot climates has no detrimental effects on egg characteristics, but has suppressive effects on egg production, feed intake and feed efficiency of laying hens.

  6. Effects of ambient temperature and early open-field response on the behaviour, feed intake and growth of fast- and slow-growing broiler strains

    DEFF Research Database (Denmark)

    Nielsen, Birte Lindstrøm

    2012-01-01

    in an open-field test on day 3 after hatching, fast-growing Ross 208 and slow-growing i657 chickens were allocated on day 13 to one of the 48 groups. Each group included either six active or six passive birds from each strain and the groups were housed in floor-pens littered with wood chips and fitted......Increased activity improves broiler leg health, but also increases the heat production of the bird. This experiment investigated the effects of early open-field activity and ambient temperature on the growth and feed intake of two strains of broiler chickens. On the basis of the level of activity...... with two heat lamps. Each group was fed ad libitum and subjected to one of the three temperature treatments: two (HH; 268C), one (HC; 168C to 268C) or no (CC; 168C) heat lamps turned on. Production and behavioural data were collected every 2 weeks until day 57. For both strains, early open-field activity...

  7. Thermal conductivity of silver loaded conductive epoxy from cryogenic to ambient temperature and its application for precision cryogenic noise measurements

    Science.gov (United States)

    Amils, Ricardo I.; Gallego, Juan Daniel; Sebastián, José Luis; Muñoz, Sagrario; Martín, Agustín; Leuther, Arnulf

    2016-06-01

    The pressure to increase the sensitivity of instrumentation has pushed the use of cryogenic Low Noise Amplifier (LNA) technology into a growing number of fields. These areas range from radio astronomy and deep space communications to fundamental physics. In this context manufacturing for cryogenic environments requires a proper thermal knowledge of the materials to be able to achieve adequate design behavior. In this work, we present experimental measurements of the thermal conductivity of a silver filled conductive epoxy (EPO-TEK H20E) which is widely used in cryogenic electronics applications. The characterization has been made using a sample preparation which mimics the practical use of this adhesive in the fabrication of cryogenic devices. We apply the data obtained to a detailed analysis of the effects of the conductive epoxy in a monolithic thermal noise source used for high accuracy cryogenic microwave noise measurements. In this application the epoxy plays a fundamental role since its limited thermal conductivity allows heating the chip with relatively low power. To our knowledge, the cryogenic thermal conductivity data of this epoxy has not been reported before in the literature in the 4-300 K temperature range. A second non-conductive epoxy (Gray Scotch-Weld 2216 B/A), also widely used in cryogenic applications, has been measured in order to validate the method by comparing with previous published data.

  8. Ozone decomposition on Ag/SiO{sub 2} and Ag/clinoptilolite catalysts at ambient temperature

    Energy Technology Data Exchange (ETDEWEB)

    Nikolov, Penko, E-mail: penmail@mail.bg [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Genov, Krassimir; Konova, Petya [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Milenova, Katya; Batakliev, Todor; Georgiev, Vladimir [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria); Kumar, Narendra [Laboratory of Industrial Chemistry, Process Chemistry Centre, Abo Akademi University, Biskopsgatan 8, 20500 Abo/Turku (Finland); Sarker, Dipak K. [School of Pharmacy and Biomolecular Sciences, University of Brighton, Lewes Road, Brighton BN2 4GJ (United Kingdom); Pishev, Dimitar [University of Chemical Technology and Metallurgy, 1756 Sofia (Bulgaria); Rakovsky, Slavcho [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2010-12-15

    Silver modified zeolite (Bulgarian natural clinoptilolite) and Ag/silica catalysts were synthesized by ion exchange and incipient wet impregnation method respectively and characterized by different techniques. DC arc-AES was used for Ag detection. XRD spectra show that Ag is loaded over the surface of the SiO{sub 2} sample and that after the ion-exchange process the HEU type structure of clinoptilolite is retained. UV-VIS (specific reflection at 310 nm) and IR (band at 695 cm{sup -1}) spectroscopy analysis proved that silver is loaded as a T-atom into zeolite channels as Ag{sup +}, instead of Na{sup +}, Ca{sup 2+}, or K{sup +} ions, existing in the natural clinoptilolite form. The samples Ag/SiO{sub 2} and Ag-clinoptilolite were tested as catalysts for decomposition of gas phase ozone. Very high catalytic activity (up to 99%) was observed and at the same time the catalysts remained active over time at room temperature.

  9. Cardiac-specific knockout of ETA receptor mitigates low ambient temperature-induced cardiac hypertrophy and contractile dysfunction

    Institute of Scientific and Technical Information of China (English)

    Yingmei Zhang; Linlin Li; Yinan Hua; Jennifer M. Nunn; Feng Dong; Masashi Yanagisawa; Jun Ren

    2012-01-01

    Cold exposure is associated with oxidative stress and cardiac dysfunction.The endothelin (ET) system,which plays a key role in myocardial homeostasis,may participate in cold exposure-induced cardiovascular dysfunction.This study was designed to examine the role of ET-1 in cold stress-induced cardiac geometric and contractile responses.Wild-type (WT) and ETA receptor knockout (ETAKO) mice were assigned to normal or cold exposure (4℃) environment for 2 and 5 weeks prior to evaluation of cardiac geometry,contractile,and intracellular Ca2+ properties.Levels of the temperature sensor transient receptor potential vanlllold (TRPV1),mitochondrlal proteins for biogenesis and oxidative phosphorylatlon,Including UCP2,HSP90,and PGC1α were evaluated.Cold stress triggered cardiac hypertrophy,depressed myocardial contractile capacity,including fractional shortening,peak shortening,and maximal velocity of shortening/relengthening,reduced intracellular Ca2+ release,prolonged intracellular Ca2+ decay and relengthening duration,generation of ROS and superoxide,as well as apoptosls,the effects of which were blunted by ETAKO.Western blotting revealed downregulated TRPV1 and PGC1α as well as upregulated UCP2 and activation of GSK3β,GATA4,and CREB in cold-stressed WT mouse hearts,which were obliterated by ETAKO.Levels of HSP90,an essential regulator for thermotolerance,were unchanged.The TRPV1 agonist SA13353 attenuated whereas TRPV1 antagonist capsazepino mimicked cold stress- or ET-1-induced cardiac anomalies.The GSK3β Inhibitor SB216763 ablated cold stress-induced cardiac contractile (but not remodeling) changes and ET-1-induced TRPV1 downregulation.These data suggest that ETAKO protects against cold exposure-induced cardiac remodeling and dysfunction mediated through TRPV1 and mitochondrlal function.

  10. Control of nanoparticle agglomeration through variation of the time-temperature profile in chemical vapor synthesis

    Science.gov (United States)

    Djenadic, Ruzica; Winterer, Markus

    2017-02-01

    The influence of the time-temperature history on the characteristics of nanoparticles such as size, degree of agglomeration, or crystallinity is investigated for chemical vapor synthesis (CVS). A simple reaction-coagulation-sintering model is used to describe the CVS process, and the results of the model are compared to experimental data. Nanocrystalline titania is used as model material. Titania nanoparticles are generated from titanium-tetraisopropoxide (TTIP) in a hot-wall reactor. Pure anatase particles and mixtures of anatase, rutile (up to 11 vol.%), and brookite (up to 29 vol.%) with primary particle sizes from 1.7 nm to 10.5 nm and agglomerate particle sizes from 24.3 nm to 55.6 nm are formed depending on the particle time-temperature history. An inductively heated furnace with variable inductor geometry is used as a novel system to control the time-temperature profile in the reactor externally covering a large wall temperature range from 873 K to 2023 K. An appropriate choice of inductor geometry, i.e. time-temperature profile, can significantly reduce the degree of agglomeration. Other particle characteristics such as crystallinity are also substantially influenced by the time-temperature profile.

  11. Ignition time of self-propagating high-temperature synthesis by laser

    Institute of Scientific and Technical Information of China (English)

    陈森昌; 迟彦惠; 史玉升; 黄树槐

    2002-01-01

    The ignition of self-propagating high-temperature synthesis (SHS) by a laser beam has very well application, but there is lack in study on the ignition process. In order to search the rule of ignition process with laser beam, ignition time of SHS was studied in detail. First one dimension ignition model was introduced: burning is the process in which one layer is ignited by next layer. Then according to Fourier conduction equation, an equation used to calculate the ignition time was deduced. Finally a series of tests were made to verify the equation. The results prove that the change of the parameters in test agrees well with the equation.

  12. Synthesis of silicon carbide in a nitrogen plasma torch: rotational temperature determination and material analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Camacho, J; Castell, R [Universidad Simon BolIvar, Departamento de Fisica, Caracas (Venezuela, Bolivarian Republic of); Castro, A; Manrique, M [Universidad Simon BolIvar, Departamento de Ciencias de los Materiales, Caracas (Venezuela, Bolivarian Republic of)], E-mail: jgruiz@usb.ve

    2008-09-07

    Experiments on silicon carbide synthesis were performed using a dc nitrogen plasma torch. Measurements of rotational temperature of nitrogen molecules by emission spectroscopy were performed, based on the band (0, 1) of the first negative system of nitrogen N{sub 2}{sup +}(B{sup 2}{sigma}{sub u}{sup +}{yields}X{sup 2}{sigma}{sub g}{sup +}) for the R branch. Three different plasma torch powers were studied in order to optimize the production of silicon carbide with our experimental set-up. The synthesized products were characterized by x-ray diffraction, scanning electron microscopy and energy dispersive x-ray spectroscopy.

  13. Synthesis of silicon carbide in a nitrogen plasma torch: rotational temperature determination and material analysis

    Science.gov (United States)

    Ruiz-Camacho, J.; Castell, R.; Castro, A.; Manrique, M.

    2008-09-01

    Experiments on silicon carbide synthesis were performed using a dc nitrogen plasma torch. Measurements of rotational temperature of nitrogen molecules by emission spectroscopy were performed, based on the band (0, 1) of the first negative system of nitrogen N_2^+ (B\\,{}^2\\Sigma_u^+ \\to X\\,{}^2\\Sigma _g^+) for the R branch. Three different plasma torch powers were studied in order to optimize the production of silicon carbide with our experimental set-up. The synthesized products were characterized by x-ray diffraction, scanning electron microscopy and energy dispersive x-ray spectroscopy.

  14. Ambient-temperature NO oxidation over amorphous CrOx-ZrO2 mixed oxide catalysts: Significant promoting effect of ZrO2

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Aiyong; Guo, Yanglong; Gao, Feng; Peden, Charles H. F.

    2017-03-01

    Three series of Cr-based mixed oxides (Cr-Co, Cr-Fe, and Cr-Ni oxides) with high specific surface areas and amorphous textures are synthesized using a novel sol-gel method. These mixed oxides, in comparison to their pure metal oxide (CrOx, Co3O4, FeOx and NiO) counterparts, display enhanced performance for catalytic oxidation of low-concentration NO at room temperature. Over best performing catalysts, 100% NO conversion can be maintained up to 30 h of operation at a high space velocity of 45,000 ml g-1 h-1. The amorphous structure is found to be critical for these catalysts to maintain high activity and durability. Cr/M (M=Co, Fe and Ni) molar ratio, nitrate precursor decomposition temperature and catalyst calcination temperature are important criteria for the synthesis of the highly active catalysts. This work was supported by National Basic Research Program of China (2013CB933200), National Natural Science Foundation of China (21577035, 21577034), Commission of Science and Technology of Shanghai Municipality (15DZ1205305) and 111 Project (B08021). Aiyong Wang gratefully acknowledges the China Scholarship Council for the Joint-Training Scholarship Program with the Pacific Northwest National Laboratory (PNNL). PNNL is operated for the U.S. Department of Energy (DOE) by Battelle. FG and CHFP are supported by the U.S. DOE/Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office.

  15. Process analysis and mechanism investigation of low temperature synthesis of nanoscale calcium hexaboride powder.

    Science.gov (United States)

    Zhang, Lin; Feng, Gang; Min, Guanghui

    2014-10-01

    The synthesis of nanoscale CaB6 powder via the low temperature chemical reaction of Calcium chloride (CaCl2) with Sodium Borohyride (NaBH4) in vacuum has been investigated in this study. The reaction temperature was determined by differential scanning calorimetry and thermogravimetric analysis (DSC and TG). Crystallization process was provided through studying the influence of heat preservation time on the crystal particles morphologies in vacuum. X-ray diffraction (XRD) was used to investigate the phase and structure of CaB6. The characterization for microstructure was performed by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The elemental analysis was conducted by X-ray photoelectron spectroscopy (XPS). It is concluded that CaB6 nanoparticles can be successfully prepared under low temperature at 500 degrees C. The results showed that in vacuum, 2 hours heat preservation time is enough for the reaction to complete at this temperature. The average size of crystal grains is 25.1 nm with high crystallinity and cubic shaped, which particles size is at the range of 20-100 nm. Longer heat preservation time more than 2 hours will make CaB6 particles connected together to form hard aggregations, that is the sintering process occurred under this temperature. However, the crystal grain size changed unobviously accompanying the holding time prolong due to the high chemical stability of CaB6. The atomic ratio of B to Ca is 5.37:1, less than but close to its stoichiometric ratio 6:1. The synthesis process and mechanism were investigated in this paper.

  16. One pot synthesis of copper nanoparticles at room temperature and its catalytic activity

    Directory of Open Access Journals (Sweden)

    Nikhil V. Suramwar

    2016-11-01

    Full Text Available A facile reduction approach with sodium borohydride as a reducing agent and starch as a stabilizing agent leads to monodispersed Cu nanoparticles in aqueous medium at an ambient condition. The synthesized nanoparticles are highly pure with no traces of CuO found on surface. They are uniform in size in the range of 40–80 nm. The Cu nanoparticles have a FCC structure as characterized by powder X-ray diffraction (XRD. Transmission electron microscopy (TEM images show that they are arranged in a regular array which is separated by starch thin layer which controls the growth as well as stabilizes the Cu nanoparticles from air oxidation. The catalytic activity of prepared Cu nanomaterial was tested in Ullman reaction for the synthesis of biphenyl from iodobenzene. We have shown in this paper that the size as well as exposed surface area of the copper nanoparticles is responsible for the increase in yield of biphenyl up to 92%. This is higher compare to the 40% yield with the normal size copper powder under the same reaction condition.

  17. Instant synthesis of gold nanoparticles at room temperature and SERS applications

    Energy Technology Data Exchange (ETDEWEB)

    Britto Hurtado, R. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Cortez-Valadez, M., E-mail: jose.cortez@unison.mx [CONACYT-Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Ramírez-Rodríguez, L.P. [Departamento de Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Larios-Rodriguez, Eduardo [Departamento de Ingeniería Química y Metalurgia, Universidad de Sonora, Rosales y Luis Encinas S/N, Hermosillo, Sonora (Mexico); Alvarez, Ramón A.B.; Rocha-Rocha, O.; Delgado-Beleño, Y.; Martinez-Nuñez, C.E.; Arizpe-Chávez, H. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico); Hernández-Martínez, A.R. [Centro de Física Aplicada y Tecnología Avanzada (CFATA), Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro C.P. 76130 (Mexico); Flores-Acosta, M. [Departamento de Investigación en Física, Universidad de Sonora, Apdo. Postal 5-88, 83190, Hermosillo, Sonora (Mexico)

    2016-08-06

    Nowadays, gold nanoparticles (AuNps) can be used in a variety of applications, thus efficient methods to produce them are necessary. Several methods have been proposed in this area, but NPs production time is one limitation of these approaches. In this study, we propose a high competitive method to synthesize gold colloidal nanoparticles, instantaneously, using no-toxic reducing agents. These substances allow the instantaneous synthesis at room temperature, even without magnetic stirrers, ovens or ultrasonic baths. Optic analysis showed two absorption bands, associated with surface Plasmon as function of HAuCl{sub 4} concentration. The nanoparticles synthesized have a 10–20 nm size, seen by the transmission electron microscopy (TEM). Therefore, it was possible to obtain several geometric patterns of AuNps, and the synthesis was performed reducing significantly processing time. Additionally, Mie and Fuchs theories were used to predict the location of the absorption bands linked to the plasmon surface in gold nanoparticles. The Surface Enhanced Raman Spectroscopy (SERS) effect was analyzed considering natural zeolite (Chabazite) as analyte, in order to determinate its possible application in soil analysis. - Highlights: • Cubic and spherical morphologies in AuNp. • Surface plasmon prediction in cubic and spherical AuNp. • Instant synthesis of AuNp. • SERS applications in soil analysis.

  18. Synthesis and characterization of Cu-MFI catalyst for the direct medium temperature range NO decomposition

    Directory of Open Access Journals (Sweden)

    Valkaj Karolina Maduna

    2016-03-01

    Full Text Available In this study the physico-chemical and catalytic properties of copper bearing MFI zeolites (Cu-MFI with different Si/Al and Si/Cu ratios were investigated. Two different methods for incorporation of metal ions into the zeolite framework were used: the ion exchange from the solution of copper acetate and the direct hydrothermal synthesis. Direct synthesis of a zeolite in the presence of copper-phosphate complexes was expected to generate more active copper species necessary for the desired reaction than the conventional ion exchange method. Direct decomposition of NO was used as a model reaction, because this reaction still offers a very attractive approach to NOX removal. The catalytic properties of zeolite samples were studied using techniques, such as XRD, SEM, EPR and nitrogen adsorption/desorption measurements at 77 K. Results of the kinetic investigation revealed that both methods are applicable for the preparation of the catalysts with active sites capable of catalyzing the NO decomposition. It was found out that Cu-MFI zeolites obtained through direct synthesis are promising catalysts for NO decomposition, especially at lower reaction temperatures. The efficiency of the catalysts prepared by both methods is compared and discussed.

  19. Functional conservation analysis and expression modes of grape anthocyanin synthesis genes responsive to low temperature stress.

    Science.gov (United States)

    Zhang, Cheng; Jia, Haifeng; Wu, Weimin; Wang, Xicheng; Fang, Jinggui; Wang, Chen

    2015-12-10

    In grape cultivation, low temperature generally increases the expression of genes involved in synthesis of anthocyanin. In this study, multi-type structural analysis of the proteins encoded by five anthocyanin biosynthesis genes VvF3H, VvPAL, VvCHS3, VvCHS2 and VvLDOX, in addition to nine of their homologous genes revealed that proteins in grapevine shared a high similarity with that in kiwi, red orange and some other species in which the biosynthesis of anthocyanin significantly influenced by low temperature as proved by previous studies. Low temperature regulatory elements were also found in the promoter region of the grapevine genes VvCHS2, VvPAL and VvF3H. These findings indicate that the functions of anthocyanin biosynthesis genes in grapevine are conservative and might be sensitive to low temperature. In order to identify the specific expression patterns of the five anthocyanin biosynthesis genes and the changes of polyphenols, anthocyanins and flavonoids under low temperature stress. The transcription analysis of the five genes and the content of polyphenols, anthocyanins and flavonoids in grape skins were examined, by using Vitis vinifera L. cv. 'Yongyou 1' and 'Juxing' berries as experimental material and treated at 4°C and 25°C for 24h, 48 h, 72 h and 96 h. The results showed that low temperature greatly enhanced the expression of the five anthocyanin biosynthesis genes. Low temperature greatly slowed down the decomposition of polyphenol, anthocyanin, and flavonoid in grape skins. Our study also found that cv. 'Juxing' responded more sensitively to low temperature than cv. 'Yongyou 1'. All the findings would provide a basis for further study on the mechanism of anthocyanin biosynthesis under environmental stress.

  20. Low temperature carbothermal and boron carbide reduction synthesis of LaB{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Muhammad; Sugo, Heber; Kisi, Erich, E-mail: Erich.Kisi@newcastle.edu.au

    2013-11-25

    Highlights: •Two simple solid-state synthesis routes to yield pure LaB{sub 6} between 1350-1450°C are reported. •The mechanism of LaB{sub 6} synthesis has been explained. •The mean crystallite size for both methods is below one micron suggesting good sinterability. •LaB{sub 6} manufactured by these procedures exhibits a Richardson work function of 2.64 eV. -- Abstract: Rare-earth hexaborides are widely used as thermionic emitters however their economic production for large scale applications such as solar thermionic electricity generation is hampered by a need to synthesise them at lower temperature without post-synthesis cleaning treatments. Two simple synthesis techniques for producing pure lanthanum hexaboride (LaB{sub 6}), carbothermal reduction using La{sub 2}O{sub 3}–boron–carbon and boron carbide reduction using La{sub 2}O{sub 3}–B{sub 4}C blends respectively were studied. Using fine grained starting materials and a mild pre-milling treatment, the carbothermal method was found to produce high-purity LaB{sub 6} at a temperature 1400 °C or below. The B{sub 4}C method also appeared from XRD and SEM analyses of abraded surfaces to produce high-purity LaB{sub 6} at 1400 °C however EDS maps of polished cross-sections revealed the presence of unreacted B{sub 4}C necessitating a temperature of 1450 °C to complete the reaction. XRD and SEM analyses indicate that the mean particle sizes of LaB{sub 6} using the boron carbide method (220 nm) is smaller than that for the carbothermal reduction method (600 nm). The finer grains of samples prepared via the boron carbide method result in a partially sintered powder. LaB{sub 6} prepared in this way is shown to have a Richardson work function of 2.64 eV.

  1. Experimental Study on Igniting Self-propagating High-temperature Synthesis by Laser

    Institute of Scientific and Technical Information of China (English)

    CHEN Senchang; SHI Yusheng; HUANG Shuhuai

    2002-01-01

    An applied range of self-propagating high-temperature synthesis (SHS) is extended under igniting by laser, but there is no study in detail on its ignition process. The ignition time of SHS by laser is studied in detail in this paper for searching igniting law. A laser beam produced by CO2 laser scans back and forth along a straight line on the surface of a sample, and an ignition time is measured under different testing conditions. The results show that the ignition time is the shortest at certain mixing time, the ignition time is longer with decreasing of the density and increasing of the sample density, and the ignition time becomes shorter when pre-heat temperature rises, but the ignition time has no relation with the area and the thickness of samples when the thickness is thicker, and it has no close relation with shield gas of N2.

  2. Effect of temperature and time on solvothermal synthesis of tetragonal BaTiO3

    Indian Academy of Sciences (India)

    Amir Habib; Nils Stelzer; Paul Angerer; Roland Haubner

    2011-02-01

    Tetragonal BaTiO3 nanoparticles are synthesized via solvothermal route in an ethanol water mixture. Ba(OH)2.8H2O is used as Ba precursor and TiO2 (P25 Degussa ∼25 nm, 30% anatase, 70% rutile) is used as Ti precursor in the Ba : Ti molar ratio 2 : 1. Effect of temperature and time study on solvothermal synthesis of BaTiO3 revealed that a moderate reaction temperature i.e. 185°C and longer reaction time favour tetragonal phase stabilization. Dissolution–precipitation appears to be the transformation mechanism for the crystallization of BaTiO3 from particulate TiO2 precursor.

  3. 40 CFR 1033.505 - Ambient conditions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Ambient conditions. 1033.505 Section 1033.505 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS... presumed that combustion air will be drawn from the ambient air. Thus, the ambient temperature limits...

  4. Application of Simplified Anaerobic Digestion Models (SADM’s for Studying the Biodegradability and Kinetics of Cow Manure at Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Yusuf O.L. MOMOH

    2014-02-01

    Full Text Available The application of a set of simplified anaerobic digestion models (SADM’s to describe the anaerobic biodegradability and kinetics of cow manure at ambient temperature was conducted in this study. It was observed that the Hill’s based biogas yield rate model was the most appropriate in describing biogas yield rate from cow manure. Parameter estimation revealed that the half saturation constant expressed as acidified substrate and volatile solids (VS equivalent were 0.163g/l and 21.9g VS/l respectively while the maximum biogas yield rate was estimated to be 1.957ml/g VS/day. The coefficient of acidogenic bacteria adaptation (n and coefficient of acetogenic/methanogenic bacterial cooperativity (m were estimated to be 1.28 and 0.65 respectively. The poor cooperativity amongst the acetogenic/methanogenic bacterial species can be attributed to poor adaptation, possibly due to interaction between ammonia and volatile fatty acids. In addition, the biodegradability and recalcitrance was estimated to be 0.42 and 0.433 respectively, while hydrolysis/acidogenesis was identified as the rate limiting step.

  5. Imaging hydrothermal systems associated with oceanic ridge: ambient noise and travel-time tomographies in the Reykjanes high-temperature area, SW-Iceland.

    Science.gov (United States)

    Jousset, Philippe; Ágústsson, Kristjan; Verdel, Arie; Blanck, Hanna; Franke, Steven; Specht, Sebastian; Stefánsson, Stefán; Tryggvason, Hörður; Erbas, Kemal; Deon, Fiorenza; Erlendsson, Ögmundur; Guðnason, Egill; Hersir, Gylfi; Ryberg, Trond; Halldórsdóttir, Sæunn; Weemstra, Cornelius; Bruhn, David; Flovenz, Ólafur; Friðleifsson, Ómar

    2015-04-01

    Analogue outcrops of hydrothermal fossil systems and simulating pressure/temperature conditions in the laboratory are classical methods for assessing supercritical conditions in magmatic environments. Scientific drilling is used when Earth surface sampled rocks cannot sufficiently explain past geological processes and when geophysical imaging does not sufficiently explain observed phenomena. However, our understanding of structural and dynamic characteristics of geothermal systems can be improved through application of advanced and/or innovative exploration technologies. Unlike resistivity imaging, active and passive seismic techniques have rarely been used in volcanic geothermal areas, because processing techniques were not adapted to geothermal conditions. Recent advances in volcano-seismology have introduced new processing techniques for assessing subsurface structures and controls on fluid flow in geothermal systems. We present here preliminary analyses of seismic records around a geothermal reservoir located both on-land and offshore along the Reykjanes Ridge, SW-Iceland. We deployed 214 on-land stations and 24 Ocean Bottom Seismometers since April 2014. We analyse more than 6 months of part of those records. We present first results of both travel-time tomography and ambient noise tomography and we discuss briefly implications for geothermal exploration in volcanic contexts.

  6. Preparation and characterization of mesoporous TiO2-sphere-supported Au-nanoparticle catalysts with high activity for CO oxidation at ambient temperature

    Science.gov (United States)

    Wang, Lili; Huang, Shouying; Zhu, Baolin; Zhang, Shoumin; Huang, Weiping

    2016-11-01

    Mesoporous TiO2-sphere-supported Au-nanoparticles (Au/m-TiO2-spheres) catalysts have been synthesized by a simple method using tetrabutyl titanate as TiO2 precursor and characterized with XRD, BET, ICP, SEM, TEM, UV-Vis DRS, XPS, as well as FT-IR. The samples with the size in the range of 200-400 nm were almost perfectly spherical. The average diameter of pores was about 3.6 nm, and the mesopore size distribution was in the range of 2-6 nm with a narrow distribution. When the catalyst was calcined at 300 °C, the Au NPs with the size ca. 5 nm were highly dispersed on the surfaces of m-TiO2 spheres and partially embedded in the supports. Remarkably, the specific surface area of the Au/m-TiO2-spheres was as high as 117 m2 g-1. The CO-adsorbed catalyst showed an apparent IR adsorption peak at 1714 cm-1 that matched with bridging model CO. It means the catalysts should be of high catalytic activity for the CO oxidation due to they could adsorb and activate CO commendably. When Au-content was 0.48 wt.%, the Au/m-TiO2-spheres could convert CO completely into CO2 at ambient temperature.

  7. Influence of applied voltage on the performance of bioelectrochemical anaerobic digestion of sewage sludge and planktonic microbial communities at ambient temperature.

    Science.gov (United States)

    Feng, Qing; Song, Young-Chae; Bae, Byung-Uk

    2016-11-01

    The influence of applied voltage on the bioelectrochemical anaerobic digestion of sewage sludge was studied at ambient temperature (25±2°C). The stability of the bioelectrochemical anaerobic digestion was considerably good in terms of pH, alkalinity and VFAs at 0.3V and 0.5V, but VFA accumulation occurred at 0.7V. The specific methane production rate (370mLCH4/L.d) was the highest at 0.3V, but the methane content (80.6%) in biogas and the methane yield (350mLCH4/gCODr) were higher at 0.5V, significantly better than those of 0.7V. The VS removal efficiency was 64-66% at 0.3V and 0.5V, but only 31% at 0.7V. The dominant species of planktonic microbial communities was Cloacamonas at 0.3V and 0.5V, but the percentage of hydrolytic bacteria species such as Saprospiraceae, Fimbriimonas, and Ottowia pentelensis was much higher at 0.7V. The optimal applied voltage for bioelectrochemical anaerobic digestion was 0.3-0.5V according to digestion performance and planktonic microbial communities.

  8. Effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid supplementation on growth performance, indices of ascites syndrome, and antioxidant capacity of broilers reared at low ambient temperature

    Science.gov (United States)

    Yang, G. L.; Zhang, K. Y.; Ding, X. M.; Zheng, P.; Luo, Y. H.; Bai, S. P.; Wang, J. P.; Xuan, Y.; Su, Z. W.; Zeng, Q. F.

    2016-08-01

    This study examined the effects of dietary DL-2-hydroxy-4(methylthio)butanoic acid (DL-HMTBA) supplementation on growth performance, antioxidant capacity, and ascites syndrome (AS) in broilers reared at low ambient temperature (LAT) from 7 to 28 days of age. Eight hundred 7-day-old broilers were randomly assigned to two ambient temperatures (LAT and normal ambient temperature [NAT]), four supplemental DL-HMTBA levels (0.17, 0.34, 0.51, and 0.68 %) of the basal diet in a 2 × 4 factorial arrangement (ten replicate pens; ten birds/pen). LAT and NAT indicate temperatures of 12-14 and 24-26 °C in two chambers, respectively, and broilers were reared at these temperatures from 7 to 28 days of age. LAT significantly decreased body weight gain ( P increased feed conversion ratio (FCR) ( P red blood cell (RBC) count ( P cell hemoglobin (day 14, P = 0.035; day 21, P = 0.003), and serum protein carbonyl level (day 21, P = 0.009), while significantly increased serum GSH content (day 14, P = 0.022; day 28, P = 0.001), SOD and GSH-Px activities at 21 days of age ( P < 0.001 and P = 0.037). The optimal supplemental DL-HMTBA levels in basal diet of broilers aged from 7 to 28 days under low or normal temperatures were similar, so the authors recommended supplemental of DL-HMTBA level was 0.46 %.

  9. Growth pattern of single fission yeast cells is bilinear and depends on temperature and DNA synthesis.

    Science.gov (United States)

    Baumgärtner, Stephan; Tolić-Nørrelykke, Iva M

    2009-05-20

    Cell growth and division have to be tightly coordinated to keep the cell size constant over generations. Changes in cell size can be easily studied in the fission yeast Schizosaccharomyces pombe because these cells have a cylindrical shape and grow only at the cell ends. However, the growth pattern of single cells is currently unclear. Linear, exponential, and bilinear growth models have been proposed. Here we measured the length of single fission yeast cells with high spatial precision and temporal resolution over the whole cell cycle by using time-lapse confocal microscopy of cells with green fluorescent protein-labeled plasma membrane. We show that the growth profile between cell separation and the subsequent mitosis is bilinear, consisting of two linear segments separated by a rate-change point (RCP). The change in growth rate occurred at the same relative time during the cell cycle and at the same relative extension for different temperatures. The growth rate before the RCP was independent of temperature, whereas the growth rate after the RCP increased with an increase in temperature, leading to clear bilinear growth profiles at higher temperatures. The RCP was not directly related to the initiation of growth at the new end (new end take-off). When DNA synthesis was inhibited by hydroxyurea, the RCP was not detected. This result suggests that completion of DNA synthesis is required for the increase in growth rate. We conclude that the growth of fission yeast cells is not a simple exponential growth, but a complex process with precise rates regulated by the events during the cell cycle.

  10. Simple mass production of zinc oxide nanostructures via low-temperature hydrothermal synthesis

    Science.gov (United States)

    Ghasaban, Samaneh; Atai, Mohammad; Imani, Mohammad

    2017-03-01

    The specific properties of zinc oxide (ZnO) nanoparticles have attracted much attention within the scientific community as a useful material for biomedical applications. Hydrothermal synthesis is known as a useful method to produce nanostructures with certain particle size and morphology however, scaling up the reaction is still a challenging task. In this research, large scale hydrothermal synthesis of ZnO nanostructures (60 g) was performed in a 5 l stainless steel autoclave by reaction between anionic (ammonia or sodium hydroxide) and cationic (zinc acetate dehydrate) precursors in low temperature. Hydrothermal reaction temperature and time were decreased to 115 °C and 2 or 6 h. In batch repetitions, the same morphologies (plate- and needle-like) with reproducible particle size were obtained. The nanostructures formed were analyzed by powder x-ray diffraction, Fourier-transform infrared spectroscopy, energy dispersive x-ray analysis, scanning electron microscopy and BET analysis. The nanostructures formed were antibacterially active against Staphylococcus aureus.

  11. Laser induced self-propagating high-temperature synthesis of TiNi alloy

    Institute of Scientific and Technical Information of China (English)

    Yongqiang Yang; Cuihong Zhang; Yunfei Yang; Lin Chen

    2005-01-01

    @@ TiNi alloy, especially porous TiNi, a good biocompatible material, can be made by laser induced selfpropagating high-temperature synthesis (SHS). A 40-W CO2 laser was used to ignite the powders of Ti and Ni, and TiNi intermetallic compound was synthesized by SHS in a reaction kettle of stainless steel.High-speed photography, X-ray diffraction, and scanning electron microscopy were used to investigate and analyze the reaction process, phase composing, and microstructure of the product, respectively. The influence factors on the reaction process and the product were discussed. The results indicate that laser induced SHS is an efficient, energy-saving method; The phase ingredient of the product consists of TiNi,Ti2Ni, and Ni3Ti. With the increase of the preparing pressure of the sample, the reacting rate decreases;With the increase of the laser power and the preheating temperature, the reacting rate increases. Under the condition of 30℃/min, the synthesis reaction had been carried out consistently and completely.

  12. Rapid room-temperature synthesis and visible-light photocatalytic properties of BiOI nanoflowers

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Feng; Wang, Jianmin; Li, Song; Cai, Jiajia; Tu, Wanhong; Lv, Xin; Qin, Gaowu, E-mail: qingw@smm.neu.edu.cn

    2015-08-05

    Highlights: • BiOI nanoflowers were synthesized via a rapid room-temperature solution synthesis method. • The shape-associated photocatalytic activities of BiOI nanostructures were reported. • The specific surface area and optical properties were examined. • Photoelectrochemical properties were performed. - Abstract: Uniform hierarchical BiOI nanoflowers composed of nanoplates with rough surfaces have been synthesized by a mild and rapid room-temperature solution synthesis approach. The effects of reaction parameters on the formation of 3D flower-like nanostructure were discussed. The morphology variations of the nanostructures were achieved by simply varying the reaction parameters in the system. The photocatalytic properties of the obtained samples for photodegradation of RhB dye under visible light irradiation were investigated, indicating that the flowerlike BiOI hierarchical nanostructure exhibits much higher photocatalytic activity than the sphere-like BiOI nanostructures owing to the larger surface areas, higher light absorption, and better photo-induced charge separation.

  13. Low-temperature Magnesiothermic Synthesis of Mesoporous Silicon Carbide from an MCM-48/Polyacrylamide Nanocomposite Precursor

    Institute of Scientific and Technical Information of China (English)

    Zahra Saeedifar; Amir Abbas Nourbakhsh; Roozbeh Javad Kalbasi; Ebrahim Karamian

    2013-01-01

    Mesoporous silicon carbide with high specific surface area was successfully synthesized from an MCM-48/polyacrylamide nanocomposite precursor in the temperature range of 550-600 ℃ (below the melting point of Mg) by means of a magnesiothermic reduction process.The MCM-48/polyacrylamide precursor nanocomposite was prepared by in-situ polymerization of acrylamide monomer in the presence of mesoporous MCM-48 synthesized by sol-gel method.The physicochemical properties and microstructures of the nanocomposite precursor and the low-temperature SiC product were characterized by X-ray diffraction (XRD),differential scanning calorimetry-thermo gravimetric analysis (DSC-TGA),transmission electron microscopy (TEM) and N2 adsorption-desorption.TEM micrographs and Brunauer-Emmett-Teller (BET) gas adsorption studies showed that the SiC powder was nanocrystalline and had a specific surface area of 330 m2/g and a mesoporosity in the range of 2-10 nm.The presence of an exothermic peak in the DSC trace corresponds to the self-combustion process of the SiC magnesiothermic synthesis.The results also show that the carbon in excess to that required to produce SiC plays a role in the reduction of the SiO2.The mechanism of magnesiothermic synthesis of mesoporous SiC is discussed.

  14. Synthesis and characterization of Ni–Cu alloy nanoparticles with a tunable Curie temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ferk, Gregor [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); Stergar, Janja [Faculty of Medicine, University of Maribor (Slovenia); Makovec, Darko [Department for Materials Synthesis, Jožef Stefan Institute, Ljubljana (Slovenia); Hamler, Anton [Faculty of Electrical Engineering and Computer Science, University of Maribor (Slovenia); Jagličić, Zvonko [Institute of Mathematics, Physics and Mechanics and Faculty of Civil and Geodetic Engineering, University of Ljubljana (Slovenia); Drofenik, Miha [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); Department for Materials Synthesis, Jožef Stefan Institute, Ljubljana (Slovenia); Ban, Irena [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); Center of Excellence NAMASTE, Ljubljana (Slovenia)

    2015-11-05

    A series of nickel–copper alloy magnetic nanoparticles with a range of Curie points from 51 °C to 63 °C were prepared by the reduction of intimately mixed nickel and copper oxides in a silica matrix using the sol–gel method. The silica matrix was subsequently removed with an etching solution, assisted by sonication. The alloy nanoparticles were characterized using X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA/SDTA), thermomagnetic analysis (TMA), transmission electron microscopy (TEM), magnetic measurements (SQUID, vibrating-sample magnetometer) and specific absorption rate measurements (SAR). The synthesized nanoparticles show a size in the range 15–20 nm, exhibited superparamagnetic behavior with a blocking temperature (T{sub B}) of approximately 135 K and a room-temperature magnetization of 3–9 emu/g, depending on the composition. The nanoparticles showed a relatively high effective anisotropy constant (K{sub eff}) and a significant heating ability in an alternating magnetic field. The synthesis method is straightforward and allows the preparation of homogeneous Ni–Cu alloy nanoparticles with a relatively narrow particle size distribution. - Highlights: • Straightforward so-gel synthesis of homogeneous Ni–Cu alloy nanoparticles. • Narrow particle size distribution and controlled Curie point. • Applications in “self-regulating magnetic fluid hyperthermia”. • Heating efficiency of nanoparticles as a function of composition and size.

  15. Low temperature route for the synthesis of rare earth transition metal borides and their hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Kramp, S.; Febri, M.; Joubert, J.C. [CNRS UMR 5628, Saint Martin d`Heres (France)

    1997-10-01

    Synthesis of rare earth-based alloys by the ORD technique consists in the reduction of rare earth oxides in a melt of calcium under argon, and simultaneous diffusion-reaction of the just formed rare earth metal with the other elements. This method has been applied with success to numerous ternary borides containing transition metals such as the magnetic alloys Y{sub 2}Co{sub 14}B, LnCo{sub 4}B, and YCo{sub 3}B{sub 2}. By using a small excess of Ca, boride particles grow in a viscous slurry media containing unreacted (melted) Ca and nanosize CaO particles. Single phase boride alloys can be obtained at 1000{degrees}C as loose micrometer-size particles of very high crystal quality as confirmed by the sharp diffraction peaks on the corresponding X-ray diagrams. Particles can be easily recovered by gentle wishing in diluted weak acid solution, and dried under vacuum at room temperature. This rather low temperature technique is particularly adapted to the synthesis of incongruent melting phases, as well as for the alloys containing volatile rare earth elements (Sm, Yb, Tb,...).

  16. A Low Temperature Route for the Synthesis of Rare Earth Transition Metal Borides and Their Hydrides

    Science.gov (United States)

    Kramp, S.; Febri, M.; Joubert, J. C.

    1997-10-01

    Synthesis of rare earth-based alloys by the ORD technique consists in the reduction of rare earth oxides in a melt of calcium under argon, and simultaneous diffusion-reaction of the just formed rare earth metal with the other elements. This method has been applied with success to numerous ternary borides containing transition metals such as the magnetic alloys Y2Co14B, LnCo4B, and YCo3B2. By using a small excess of Ca, boride particles grow in a viscous slurry media containing unreacted (melted) Ca and nanosize CaO particles. Single phase boride alloys can be obtained at 1000°C as loose micrometer-size particles of very high crystal quality as confirmed by the sharp diffraction peaks on the corresponding X-ray diagrams. Particles can be easily recovered by gentle washing in diluted weak acid solution, and dried under vacuum at room temperature. This rather low temperature technique is particularly adapted to the synthesis of incongruent melting phases, as well as for the alloys containing volatile rare earth elements (Sm, Yb, Tb,…).

  17. A stochastic model for transmission, extinction and outbreak of Escherichia coli O157:H7 in cattle as affected by ambient temperature and cleaning practices

    KAUST Repository

    Wang, Xueying

    2013-07-18

    Many infectious agents transmitting through a contaminated environment are able to persist in the environment depending on the temperature and sanitation determined rates of their replication and clearance, respectively. There is a need to elucidate the effect of these factors on the infection transmission dynamics in terms of infection outbreaks and extinction while accounting for the random nature of the process. Also, it is important to distinguish between the true and apparent extinction, where the former means pathogen extinction in both the host and the environment while the latter means extinction only in the host population. This study proposes a stochastic-differential equation model as an approximation to a Markov jump process model, using Escherichia coli O157:H7 in cattle as a model system. In the model, the host population infection dynamics are described using the standard susceptible-infected-susceptible framework, and the E. coli O157:H7 population in the environment is represented by an additional variable. The backward Kolmogorov equations that determine the probability distribution and the expectation of the first passage time are provided in a general setting. The outbreak and apparent extinction of infection are investigated by numerically solving the Kolmogorov equations for the probability density function of the associated process and the expectation of the associated stopping time. The results provide insight into E. coli O157:H7 transmission and apparent extinction, and suggest ways for controlling the spread of infection in a cattle herd. Specifically, this study highlights the importance of ambient temperature and sanitation, especially during summer. © 2013 Springer-Verlag Berlin Heidelberg.

  18. Effect of ambient temperature on the thermoregulatory and locomotor stimulant effects of 4-methylmethcathinone in Wistar and Sprague-Dawley rats.

    Directory of Open Access Journals (Sweden)

    M Jerry Wright

    Full Text Available The drug 4-methylmethcathinone (4-MMC; aka, mephedrone, MMCAT, "plant food", "bath salts" is a recent addition to the list of popular recreational psychomotor-stimulant compounds. Relatively little information about this drug is available in the scientific literature, but popular media reports have driven recent drug control actions in the UK and several US States. Online user reports of subjective similarity to 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy" prompted the current investigation of the thermoregulatory and locomotor effects of 4-MMC. Male Wistar and Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1-10 mg/kg using an implantable radiotelemetry system under conditions of low (23°C and high (27°C ambient temperature. A reliable reduction of body temperature was produced by 4-MMC in Wistar rats at 23°C or 27°C with only minimal effect in Sprague-Dawley rats. Increased locomotor activity was observed after 4-MMC administration in both strains with significantly more activity produced in the Sprague-Dawley strain. The 10 mg/kg s.c. dose evoked greater increase in extracellular serotonin, compared with dopamine, in the nucleus accumbens. Follow-up studies confirmed that the degree of locomotor stimulation produced by 10 mg/kg 4-MMC was nearly identical to that produced by 1 mg/kg d-methamphetamine in each strain. Furthermore, hypothermia produced by the serotonin 1(A/7 receptor agonist 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT was similar in each strain. These results show that the cathinone analog 4-MMC exhibits thermoregulatory and locomotor properties that are distinct from those established for methamphetamine or MDMA in prior work, despite recent evidence of neuropharmacological similarity with MDMA.

  19. A thiol-activated lipase from Trichosporon asahii MSR 54: detergent compatibility and presoak formulation for oil removal from soiled cloth at ambient temperature.

    Science.gov (United States)

    Kumar, S Suresh; Kumar, Lalit; Sahai, Vikram; Gupta, Rani

    2009-03-01

    An alkaline lipase from Trichosporon asahii MSR 54 was used to develop presoak formulation for removing oil stains at ambient temperature. The lipase was produced in a reactor followed by concentration by ultrafiltration and then it was dried with starch. The biochemical characteristics of enzyme showed that it was an alkaline lipase having pH activity in the range of pH 8.0-10.0 and temperature in the range of 25-50 degrees C. The present lipase was active >80% at 25 degrees C. The lipase was cystein activated with fourfold enhancement in presence of 5 mM cystein and likewise the activity was also stimulated in presence of papain hydrolysate which served as source of cystein. The presoak formulation consisted of two components A and B, component A was enzyme additive and B was a mixture of carbonate/bicarbonate source of alkali and papain hydrolysate as source of cystein. The results indicated that the presoaking in enzyme formulation followed by detergent washing was a better strategy for stain removal than direct washing with detergent in presence of lipase. Further, it was observed that 0.25% presoak component B in presence of 100 U enzyme component A (0.1 g) was the best formulation in removing maximum stain from mustard oil/triolein soiled clothes as indicated by increase in reflectance which was found equal to that of control cloth. The lipase action in presoaked formulation was clearly indicated by quantitated fatty acid release and also the TLC results of wash water, where oil hydrolytic products were visible only in presence of enzyme in the treatment. The wash performance carried at 25 degrees C indicated that washing at 25 degrees C was at par with that at 40 degrees C as indicated by similar reflectance of the washed cloth piece though qualitative fatty acid release was higher at 40 degrees C.

  20. Evidence for organic synthesis in high temperature aqueous media - facts and prognosis

    Science.gov (United States)

    Simoneit, Bernd R. T.

    1995-01-01

    Hydrothermal systems are common along the active tectonic areas of the earth. Potential sites being studied for organic matter alteration and possible organic synthesis are spreading ridges, off-axis systems, back-arc activity, hot spots, volcanism, and subduction. Organic matter alteration, primarily reductive and generally from immature organic detritus, occurs in these high temperature and rapid fluid flow hydrothermal regimes. Hot circulating water (temperature range - warm to greater than 400 C) is responsible for these molecular alterations, expulsion and migration. Compounds that are obviously synthesized are minor components because they are generally masked by the pyrolysis products formed from contemporary natural organic precursors. The reactivity of organic compounds in hot water (200-350 C) has been studied in autoclaves, and supercritical water as a medium for chemistry has also been evaluated. This high temperature aqueous organic chemistry and the strong reducing conditions of the natural systems suggest this as an important route to produce organic compounds on the primitive earth. Thus a better understanding of the potential syntheses of organic compounds in hydrothermal systems will require investigations of the chemistry of condensation, autocatalysis, catalysis and hydrolysis reactions in aqueous mineral buffered systems over a range of temperatures from warm to greater than 400 C.

  1. Synthesis of high saturation magnetic iron oxide nanomaterials via low temperature hydrothermal method

    Science.gov (United States)

    Bhavani, P.; Rajababu, C. H.; Arif, M. D.; Reddy, I. Venkata Subba; Reddy, N. Ramamanohar

    2017-03-01

    Iron oxide nanoparticles (IONPs) were synthesized through a simple low temperature hydrothermal approach to obtain with high saturation magnetization properties. Two series of iron precursors (sulfates and chlorides) were used in synthesis process by varying the reaction temperature at a constant pH. The X-ray diffraction pattern indicates the inverse spinel structure of the synthesized IONPs. The Field emission scanning electron microscopy and high resolution transmission electron microscopy studies revealed that the particles prepared using iron sulfate were consisting a mixer of spherical (16-40 nm) and rod (diameter 20-25 nm, length distributed spherical shapes with size range 5-20 nm. On other hand, the IONPs synthesized at reaction temperature of 190 °C has spherical (16-46 nm) morphology in both series. The band gap values of IONPs were calculated from the obtained optical absorption spectra of the samples. The IONPs synthesized using iron sulfate at temperature of 130 °C exhibited high saturation magnetization (MS) of 103.017 emu/g and low remanant magnetization (Mr) of 0.22 emu/g with coercivity (Hc) of 70.9 Oe, which may be attributed to the smaller magnetic domains (dm) and dead magnetic layer thickness (t).

  2. Influence of the temperature in the electrochemical synthesis of cobalt ferrites nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mazario, E. [Departamento de Quimica Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, UAM, C/Francisco Tomas y Valiente 7, 28049 Cantoblanco, Madrid (Spain); Morales, M.P. [Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Ines de la Cruz 3, 28049 Cantoblanco, Madrid (Spain); Galindo, R. [Departamento de Quimica Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, UAM, C/Francisco Tomas y Valiente 7, 28049 Cantoblanco, Madrid (Spain); Herrasti, P., E-mail: pilar.herrasti@uam.es [Departamento de Quimica Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, UAM, C/Francisco Tomas y Valiente 7, 28049 Cantoblanco, Madrid (Spain); Menendez, N. [Departamento de Quimica Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, UAM, C/Francisco Tomas y Valiente 7, 28049 Cantoblanco, Madrid (Spain)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Cobalt ferrite nanoparticles were synthesized by new electrochemical method. Black-Right-Pointing-Pointer Temperature affects to percentage of inclusion of Co and diameter of the synthesized nanoparticles. Black-Right-Pointing-Pointer At 80 Degree-Sign C and current densities of 50/25 mA cm{sup -2} applied to Fe and Co, respectively, a stoichiometric CoFe{sub 2}O{sub 4} nanoparticles with 40 nm of diameter were obtained. - Abstract: A new electrochemical method to synthesize cobalt ferrite nanoparticles has been developed. Magnetic measurement, Moessbauer spectroscopy, X-ray diffraction, inductive coupled plasma spectroscopy, and transmission electron microscopy were carried out to characterize the cobalt ferrites synthesized at different temperatures between 25 Degree-Sign C and 80 Degree-Sign C. These techniques confirm the efficiency of the electrochemical method. At room temperature a mixture of different compounds was obtained with a particle diameter around 20 nm, while at 80 Degree-Sign C the synthesis of cobalt ferrite leads to a stoichiometric spinel, with a crystallite size of 40 nm measured by Scherrer equation. The temperature was defined as an important parameter to obtain stoichiometric ferrites and different diameters.

  3. Gas temperature measurements inside a hot wall chemical vapor synthesis reactor.

    Science.gov (United States)

    Notthoff, Christian; Schilling, Carolin; Winterer, Markus

    2012-11-01

    One key but complex parameter in the chemical vapor synthesis (CVS) of nanoparticles is the time temperature profile of the gas phase, which determines particle characteristics such as size (distribution), morphology, microstructure, crystal, and local structure. Relevant for the CVS process and for the corresponding particle characteristics is, however, not the T(t)-profile generated by an external energy source such as a hot wall or microwave reactor but the temperature of the gas carrying reactants and products (particles). Due to a complex feedback of the thermodynamic and chemical processes in the reaction volume with the external energy source, it is very difficult to predict the real gas phase temperature field from the externally applied T(t)-profile. Therefore, a measurement technique capable to determine the temperature distribution of the gas phase under process conditions is needed. In this contribution, we demonstrate with three proof of principle experiments the use of laser induced fluorescence thermometry to investigate the CVS process under realistic conditions.

  4. Gas temperature measurements inside a hot wall chemical vapor synthesis reactor

    Science.gov (United States)

    Notthoff, Christian; Schilling, Carolin; Winterer, Markus

    2012-11-01

    One key but complex parameter in the chemical vapor synthesis (CVS) of nanoparticles is the time temperature profile of the gas phase, which determines particle characteristics such as size (distribution), morphology, microstructure, crystal, and local structure. Relevant for the CVS process and for the corresponding particle characteristics is, however, not the T(t)-profile generated by an external energy source such as a hot wall or microwave reactor but the temperature of the gas carrying reactants and products (particles). Due to a complex feedback of the thermodynamic and chemical processes in the reaction volume with the external energy source, it is very difficult to predict the real gas phase temperature field from the externally applied T(t)-profile. Therefore, a measurement technique capable to determine the temperature distribution of the gas phase under process conditions is needed. In this contribution, we demonstrate with three proof of principle experiments the use of laser induced fluorescence thermometry to investigate the CVS process under realistic conditions.

  5. Synthesis of nanostructured carbon by chlorination of calcium carbide at moderate temperatures and its performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dai Chunling [School of Chemistry, Xiangtan University, Hunan 411105 (China); Wang, Xianyou [School of Chemistry, Xiangtan University, Hunan 411105 (China)], E-mail: wxianyou@yahoo.com; Wang Ying [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Hubei 430073 (China); Li Na; Wei Jianliang [School of Chemistry, Xiangtan University, Hunan 411105 (China)

    2008-12-01

    A new type of one-step preparation technique for the calcium carbide-derived carbon (CaC{sub 2}-CDC) was developed. In this study, CaC{sub 2}-CDC was synthesized from CaC{sub 2} in a freshly prepared chlorine environment in the temperature range of 100-600 deg. C. The structure and morphology of as-prepared CaC{sub 2}-CDC were studied by X-ray diffraction, transmission electron microscopy and nitrogen sorption experiment. Analysis of X-ray diffraction and transmission electron microscopy showed that CaC{sub 2}-CDC is an amorphous nanoporous material, and the structure depended on the synthesis temperature. The resultant carbon demonstrated narrow pore size distribution (PSD) and specific surface area (SSA) close to 800 m{sup 2} g{sup -1} (for nitrogen sorption) at a synthesized temperature of 100 deg. C. Increasing the reaction temperature above 400 deg. C resulted in a lower SSA of CaC{sub 2}-CDC due to the beginning of graphitization tendency. The nanoporous structure and narrow PSD of CaC{sub 2}-CDC indicated potential application as electrode materials in supercapacitor. The CaC{sub 2}-CDC exhibited a specific capacitance of 127.7 F g{sup -1} measured from the three-electrode cyclic voltammetry experiment at 10 mV s{sup -1}.

  6. The facile and low temperature synthesis of nanophase hydroxyapatite crystals using wet chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Dhand, Vivek [Department of Mechanical Engineering, College of Engineering, Kyung Hee University, 446–701 Yongin (Korea, Republic of); Rhee, K.Y., E-mail: rheeky@khu.ac.kr [Department of Mechanical Engineering, College of Engineering, Kyung Hee University, 446–701 Yongin (Korea, Republic of); Park, Soo-Jin, E-mail: sjpark@inha.ac.kr [Department of Chemistry, Inha University, Incheon (Korea, Republic of)

    2014-03-01

    A simple and facile wet chemistry route was used to synthesize nanophase hydroxyapatite (HaP) crystals at low temperature. The synthesis was carried out at a pH of 11.0 and at a temperature of 37 °C. The resulting samples were washed several times and subjected to further analysis. XRD studies revealed that the HaP crystals were polycrystalline in nature with a crystallite size of ∼ 15–60 ± 5 nm. SEM-EDXA images confirmed the presence of calcium (Ca), phosphorous (P), and oxygen (O) peaks. Likewise, FTIR confirmed the presence of characteristic phosphate and hydroxyl peaks in samples. Lastly, HRTEM images clearly showed distinctive lattice fringes positioned in the 100 and 002 planes. TGA analysis shows that HaP crystals can withstand higher calcination temperatures and are thermally stable. - Highlights: • Facile and low temperature nanophase HaP crystals synthesized at pH 11 and 37 °C • Electron microscopy image of HaP shows characteristic rice grain like morphology. • FTIR results show the characteristic and fingerprint functional groups of HaP. • Thermal stability of HaP crystals up to 500 °C • Growth of Hap crystals occur parallel to c-axis and a possible mechanism proposed.

  7. Self-Propagating High-Temperature Synthesis in the Ti-C-Ni-Mo System on Application of Powerful Ultrasound

    Science.gov (United States)

    Kulak, M. M.; Khina, B. B.

    2014-03-01

    An experimental setup has been developed and a study has been made of the self-propagating high-temperature synthesis in a Ti-C-Ni-Mo system under the conditions of action of ultrasonic vibrations. The influence of the amplitude of ultrasonic vibrations on the combustion rate and temperature and on the phase composition and structure of the derived composite material based on titanium carbide with a metal binder has been determined. The heat-transfer coefficient on the surface of a sample for vibrations at ultrasound frequency has been evaluated. Consideration has been given to possible mechanisms of influence of ultrasonic vibrations on the process of self-propagating high-temperature synthesis. It has been shown that the reduction in the synthesis temperature is due to the cooling of the sample because of the forced convection of the surrounding gas, whereas the change in the structure of the synthesized material is related to the change in the conditions of high-temperature heterogeneous interaction in the wave of self-propagating high-temperature synthesis.

  8. Temperature Fluctuation Synthesis/Simultaneous Densification and Microstructure Control of Titanium Silicon Carbide (Ti3SiC2) Ceramics

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@A novel temperature fluctuation synthesis/simultaneous densification process was developed for the preparation of Ti3SiC2 bulk ceramics. In this process, Si is used as an in-situ liquid forming phase and it is favorable for both the solid-liquid synthesis and the densification of Ti3SiC2 ceramics. The present work demonstrated that the temperature fluctuation synthesis/simultaneous densification process is one of the most effective and simple methods for the preparation of Ti3SiC2 bulk materials providing relatively low synthesis temperature, short reaction time, and simultaneous synthesis and densification. This work also showed the capability to control the microstructure, e.g., the preferred orientation, of the bulk Ti3SiC2 materials simply by applying the hot pressing pressure at different stages of the temperature fluctuation process. And textured Ti3SiC2 bulk materials with {002} faces of laminated Ti3SiC2 grains normal to the hot pressing axis were prepared.

  9. New process of low-temperature methanol synthesis from CO/CO2/H2 based on dual-catalysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new process of low-temperature methanol synthesis from CO/CO2/H2 based on dual-catalysis has been developed. Some alcohols, especially 2-alcohol, were found to have high cata-lytic promoting effect on the synthesis of methanol from CO hydrogenation. At 443 K and 5 MPa, the synthesis of methanol could process high effectively, resulting from the synergic catalysis of Cu/ZnO solid catalyst and 2-alcohol solvent catalyst. The primary results showed that when 2-butanol was used as reaction solvent, the one-pass average yield and the selectivity of methanol, in 40 h con-tinuous reaction at temperature as low as 443 K and 5 MPa, were high up to 46.51% and 98.94% respectively. The catalytic activity was stable and the reaction temperature was 80 K or so lower than that in current industry synthesis process. This new process hopefully will become a practical method for methanol synthesis at low temperature.

  10. New process of low-temperature methanol synthesis from CO/CO2/H2 based on dual-catalysis

    Institute of Scientific and Technical Information of China (English)

    曾健青; TSUBAKINoritatsu; FUJIMOTOKaoru

    2002-01-01

    A new process of low-temperature methanol synthesis from CO/CO2/H2 based on dual-catalysis has been developed. Some alcohols, especially 2-alcohol, were found to have high catalytic promoting effect on the synthesis of methanol from CO hydrogenation. At 443 K and 5 MPa, the synthesis of methanol could process high effectively, resulting from the synergic catalysis of Cu/ZnO solid catalyst and 2-alcohol solvent catalyst. The primary results showed that when 2-butanol was used as reaction solvent, the one-pass average yield and the selectivity of methanol, in 40 h continuous reaction at temperature as low as 443 K and 5 MPa, were high up to 46.51% and 98.94% respectively. The catalytic activity was stable and the reaction temperature was 80 K or so lower than that in current industry synthesis process. This new process hopefully will become a practical method for methanol synthesis at low temperature.

  11. Temperatura e enriquecimento ambiental sobre o bem-estar de coelhos em crescimento Temperature and environmental enrichment on the welfare of growing rabbits

    Directory of Open Access Journals (Sweden)

    Estela Valéria Siloto

    2009-04-01

    Full Text Available O efeito da temperatura e o efeito do enriquecimento do piso de gaiola sobre o bem-estar de coelhos em crescimento foram avaliados. Quarenta e oito coelhos do grupo genético Botucatu, desmamados aos 35 dias de idade, foram alojados em Câmara Climática, quatro por gaiola (1,00 x 0,60 x 0,40m, em 12 gaiolas que tinham (ou não metade do piso coberto com cama de palha. As gaiolas foram instaladas metade em sala com temperatura ambiente e metade em sala resfriada. Os animais tiveram livre acesso à ração balanceada e à água nos dois tipos de piso. Para se avaliar o bem-estar, foram realizadas cinco observações de 24 horas cada, uma por semana, sendo registradas as freqüências dos comportamentos: lúdico, estereotipado, exploratório, cuidados corporais e interação e comparadas entre gaiolas enriquecidas ou não nas duas salas. A média de temperatura e a média de umidade relativa do ar foram: 23,6°C e 78,7% na sala natural e 20,6°C e 71,0% na sala resfriada. O comportamento lúdico foi mais freqüente nas gaiolas enriquecidas (7,6 vs 4,3% sala natural e 7,8 vs 3,8% sala resfriada, P0,01. Coelhos mantidos em temperatura natural preferiram a grade à cama de palha (77,9 vs. 22,1%, P>0,01, enquanto na sala resfriada eles não mostraram preferência em relação ao piso (45,9 vs 54,1%, P=0,41. Em sala resfriada, o enriquecimento com palha favoreceu o bem-estar animal.The effects of temperature and cage floor enrichment on the welfare of growing rabbits were evaluated. Forty-eight rabbits from the Botucatu genetic group, weaned at 35 days of age were housed in an Environmental Chamber, four per cage (1.00 x 0.60 x 0.40m, in 12 cages that had (or not half of the floor covered with litter straw. The cages were housed half in a room temperature chamber and half in a refrigerated chamber. Animals had free access to a balanced feed and water in the two types of floor. In order to evaluate welfare, five 24-hour observations were carried out

  12. Temperaturas superficiais de telhas e sua relação com o ambiente térmico Superficial temperatures of tiles and the relation with thermal environment

    Directory of Open Access Journals (Sweden)

    Carlos A. de P. Sampaio

    2011-04-01

    Full Text Available Este trabalho teve como objetivo a análise de temperaturas de telhas de barro, de fibrocimento com pintura branca na face superior e de aço zincado e sua relação com o ambiente térmico, quantificando também os Índices de Temperatura e Umidade (ITU, de Temperatura de Globo e Umidade (ITGU e Carga Térmica de Radiação (CTR. As análises foram realizadas em modelos de edificações e na área não sombreada. Os resultados mostraram que as telhas cerâmicas e de fibrocimento apresentaram comportamentos térmicos semelhantes, sendo que a opção pela telha de fibrocimento de 5 mm, pintada de branca na sua face superior, é vantajosa economicamente. As telhas metálicas superaram os 53 °C na sua superfície e foram piores no conforto térmico comparado com as outras telhas. O ITGU foi superior na indicação do conforto térmico em relação ao ITU, principalmente no verão. Houve redução significativa da CTR pelas telhas em relação à área não sombreada.The objective of this study was the analysis of temperatures of clay tiles, galvanized steel tiles and fiber-cement tiles with white painting on the roof and his relation with the thermal environment, in winter and summer conditions. The experiment was carried out in models of constructions quantifying the internal and extern temperatures from the tiles (TS, Temperature and humidity index (THI, Black Globe and Humidity (BGHI and Thermal Load of Radiation (TLR were employed for the characterization of the thermal environmental. The measured were performed inside and outside the housing. The results showed that the ceramic tiles and the fiber-cement tiles presented similar thermal behaviors and the choice of fiber-cement tiles of 5 mm with white painting on the roof is economically advantageous. The metal tiles were the ones that most heated up surpassing 53ºC in his surface and the worst regarding to the thermal comfort compared with the other tiles. The THI was not accurate for

  13. Timing matters: the underappreciated role of temperature ramp rate for shape control and reproducibility of quantum dot synthesis

    KAUST Repository

    Baumgardner, William J.

    2012-01-01

    Understanding the coupled kinetic and thermodynamics factors governing colloidal nanocrystals nucleation and growth are critical factors in the predictable and reproducible synthesis of advanced nanomaterials. We show that the temporal temperature profile is decisive in tuning the particle shape from pseudo-spherical to monodisperse cubes. The shape of the nanocrystals was characterized by transmission electron microscopy and X-ray diffraction. We introduce a mechanism for the shape controlled synthesis in the context of temperature-dependent nucleation and growth and provide experimental evidence to support it. © 2013 The Royal Society of Chemistry.

  14. Surface-Bound Intermediates in Low-Temperature Methanol Synthesis on Copper. Participants and Spectators

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yong; Mei, Donghai; Peden, Charles HF; Campbell, Charles T.; Mims, Charles A.

    2015-11-03

    The reactivity of surface adsorbed species present on copper catalysts during methanol synthesis at low temperatures was studied by simultaneous infrared spectroscopy (IR) and mass spectroscopy (MS) measurements during “titration” (transient surface reaction) experiments with isotopic tracing. The results show that adsorbed formate is a major bystander species present on the surface under steady-state methanol synthesis reaction conditions, but it cannot be converted to methanol by reaction with pure H2, nor with H2 plus added water. Formate-containing surface adlayers for these experiments were produced during steady state catalysis in (a) H2:CO2 (with substantial formate coverage) and (b) moist H2:CO (with no IR visible formate species). Both these reaction conditions produce methanol at steady state with relatively high rates. Adlayers containing formate were also produced by (c) formic acid adsorption. Various "titration" gases were used to probe these adlayers at modest temperatures (T = 410-450K) and 6 bar total pressure. Methanol gas (up to ~1% monolayer equivalent) was produced in "titration" from the H2:CO2 catalytic adlayers by H2 plus water, but not by dry hydrogen. The decay in the formate IR features accelerated in the presence of added water vapor. The H2:CO:H2O catalytic adlayer produced similar methanol titration yields in H2 plus water but showed no surface formate features in IR (less than 0.2% monolayer coverage). Finally, formate from formic acid chemisorption produced no methanol under any titration conditions. Even under (H2:CO2) catalytic reaction conditions, isotope tracing showed that pre-adsorbed formate from formic acid did not contribute to the methanol produced. Although non-formate intermediates exist during low temperature methanol synthesis on copper which can be converted to methanol gas

  15. The effect of natural and synthetic antioxidants on performance, egg quality and blood constituents of laying hens grown under high ambient temperature

    Directory of Open Access Journals (Sweden)

    Mohammed A. Al-Harthi

    2014-06-01

    Full Text Available A total of 216 laying hens was kept at high ambient temperature (32±4°C, 60% relative humidity from week 24 to 32 of age. Birds were divided in 8 treatments with 9 replicates of 3 hens each. The groups were fed the same basal diet and submitted to these dietary treatments: control, un-supplemented; green tea (GT, fed GT at 1 g/kg diet; brown marine algae (BMA, fed BMA at 1 g/kg diet; vitamin E (vit. E, fed vit. E at 300 mg/kg diet; GT+BMA, fed GT and BMA at 1 g/kg of each; GT+vit. E, fed GT and vit. E at 1 g and 300 mg/kg, respectively; BMA+vit. E, fed BMA and vit. E at 1 g and 300 mg/kg, respectively. Feeding BMA at 0.1% increased laying rate by 1.2% and improved feed conversion ratio by 5.2% compared to the control. Vitamin E significantly increased shell thickness by 6.6% and Haugh unit by 4.6% compared to the control. In addition, BMA+vit. E or GT+vit. E increased yolk colour by 9.1 and 10.7%, and Haugh unit of stored eggs by 10.9 and 11.1%. Cholesterol of fresh eggs and plasma were significantly decreased by 16.0 and 9.4% due to supplementation with BMA, and by 19.2 and 8.1% with vit. E addition. Plasma phosphorus increased by 19.1% after vit. E+BMA supplementation. In conclusion, use of BMA or vit. E or GT in laying hens diets which grow under heat stress is recommended as it improves production performance and egg quality.

  16. Ion mobility spectrometric analysis of vaporous chemical warfare agents by the instrument with corona discharge ionization ammonia dopant ambient temperature operation.

    Science.gov (United States)

    Satoh, Takafumi; Kishi, Shintaro; Nagashima, Hisayuki; Tachikawa, Masumi; Kanamori-Kataoka, Mieko; Nakagawa, Takao; Kitagawa, Nobuyoshi; Tokita, Kenichi; Yamamoto, Soichiro; Seto, Yasuo

    2015-03-20

    The ion mobility behavior of nineteen chemical warfare agents (7 nerve gases, 5 blister agents, 2 lachrymators, 2 blood agents, 3 choking agents) and