WorldWideScience

Sample records for water activity temperature

  1. Interacting Temperature and Water Activity Modulate Production of ...

    African Journals Online (AJOL)

    Online2PDF.com

    This study evaluated the effect of temperature and water activity (aw) on destruxin A (DA) production by two strains of M. ... 32. West African Journal of Applied Ecology, vol. 24 (1), 2016 water stress on destruxin production in ..... Rearing tomato whitefly and field evaluation of modified and unmodified conidia of. Beauveria ...

  2. Water-temperature data acquisition activities in the United States

    Science.gov (United States)

    Pauszek, F.H.

    1972-01-01

    Along with the growing interest in water quality during the last decade, the need for data on all types of water-quality parameters has also increased. One parameter of particular interest, because of its many ramifications, is temperature. It influences many of the chemical and physical processes that take place in water. The solubility of gases--for example, oxygen and carbon dioxide--and the solution of mineral matter in water are functions of temperature. Such physical properties as density and viscosity vary with temperature. Oxidation of organic materials, as well as algal and bacterial growth, is promoted or retarded by favorable or unfavorable temperatures. Further, temperature bears on the utility of water: as a source of public water supplies; for industrial use, particularly if the water is used for cooling; and in the field of recreation involving contact sports, fishing, and fish culture. In recent years, temperature changes resulting from inflow of heated industrial waste, particularly effluent from power generating plants, have increased the need for temperature data to determine the degree of change, its effect on ecology, and the effect of any remedial action. Thus, because of the many extensive and intensive effects, a large amount of temperature data is collected on surface and ground waters by many agencies throughout the country. Moreover, because of its importance, there is a widespread interest in temperature even by those who are not active collectors of the data themselves. The industrialist, the manager, the public official, and others at one time or another may have need for temperature data and may well raise the questions: Who is collecting temperature data? What is the extent of the activity? Where are the data being collected? The purpose of this report is to answer these questions. The information in the report is confined to the activities of Federal and non-Federal agencies. It is based on information furnished to the Office of

  3. The effect of water activity and temperature on the production of some mycotoxins

    NARCIS (Netherlands)

    Northolt, M.D.

    1979-01-01

    Preventing mold from growing and producing mycotoxins requires knowledge of the conditions under which each of the toxinogenic molds becomes active. In this investigation the relation between fungal growth and mycotoxin formation and the factors water activity and temperature is studied.

  4. Development and validation of a combined temperature, water activity, pH model for bacterial growth rate Lactobacillus curvatus

    NARCIS (Netherlands)

    Wijtzes, T.; Rombouts, F.M.; Kant-Muermans, M.L.T.; Riet, K. van 't; Zwietering, M.H.

    2001-01-01

    A model was established to predict growth rate as a function of temperature, pH and water activity. The model is based on two, earlier developed models, one for growth rate as a function of temperature and water activity and the other for growth rate as a function of temperature and pH. Based on the

  5. Development and validation of a combined temperature, water activity, pH model for bacterial growth rate of Lactobacillus curvatus

    NARCIS (Netherlands)

    Wijtzes, T.; Rombouts, F.M.; Kant-Muermans, M.L.T.; Riet, van 't K.; Zwietering, M.H.

    2001-01-01

    A model was established to predict growth rate as a function of temperature, pH and water activity. The model is based on two, earlier developed models, one for growth rate as a function of temperature and water activity and the other for growth rate as a function of temperature and pH. Based on the

  6. Effect of pH, temperature and water activity on the inhibition of ...

    African Journals Online (AJOL)

    WiN 7

    2012-01-31

    Jan 31, 2012 ... Effect of pH, temperature and water activity on the inhibition of Botrytis cinerea by Bacillus amyloliquefaciens isolates. Hamdache Ahlem1, Ezziyyani Mohammed2, Alain Badoc3 and Lamarti Ahmed1*. 1Département de Biologie, Faculté des Sciences, Equipe de Biotechnologies Végétales. M‟hannech II ...

  7. Extremophilic fungi in arctic ice: a relationship between adaptation to low temperature and water activity

    DEFF Research Database (Denmark)

    Gunde-Cimerman, N.; Sonjak, S.; Zalar, P.

    2003-01-01

    Little is known about fungal diversity in extremely cold regions. Low temperatures induce the formation of ice crystals and therefore also the creation of low water activity (a(w)). These are the dominant factors in external chemistry that influence microbial biota in cold regions. Therefore, we ...

  8. Photosynthesis, Transpiration, Leaf Temperature, and Stomatal Activity of Cotton Plants under Varying Water Potentials.

    Science.gov (United States)

    Pallas, J E; Michel, B E; Harris, D G

    1967-01-01

    Cotton plants, Gossypium hirsutum L. were grown in a growth room under incident radiation levels of 65, 35, and 17 Langleys per hour to determine the effects of vapor pressure deficits (VPD's) of 2, 9, and 17 mm Hg at high soil water potential, and the effects of decreasing soil water potential and reirrigation on transpiration, leaf temperature, stomatal activity, photosynthesis, and respiration at a VPD of 9 mm Hg.Transpiration was positively correlated with radiation level, air VPD and soil water potential. Reirrigation following stress led to slow recovery, which may be related to root damage occurring during stress. Leaf water potential decreased with, but not as fast as, soil water potential.Leaf temperature was usually positively correlated with light intensity and negatively correlated with transpiration, air VPD, and soil water. At high soil water, leaf temperatures ranged from a fraction of 1 to a few degrees above ambient, except at medium and low light and a VPD of 19 mm Hg when they were slightly below ambient, probably because of increased transpirational cooling. During low soil water leaf temperatures as high as 3.4 degrees above ambient were recorded. Reirrigation reduced leaf temperature before appreciably increasing transpiration. The upper leaf surface tended to be warmer than the lower at the beginning of the day and when soil water was adequate; otherwise there was little difference or the lower surface was warmer. This pattern seemed to reflect transpiration cooling and leaf position effects.Although stomata were more numerous in the lower than the upper epidermis, most of the time a greater percentage of the upper were open. With sufficient soil water present, stomata opened with light and closed with darkness. Fewer stomata opened under low than high light intensity and under even moderate, as compared with high soil water. It required several days following reirrigation for stomata to regain original activity levels.Apparent photosynthesis

  9. Effect of water activity and temperature on the growth of Eurotium species isolated from animal feeds.

    Science.gov (United States)

    Greco, Mariana; Pardo, Alejandro; Pose, Graciela; Patriarca, Andrea

    Xerophilic fungi represent a serious problem due to their ability to grow at low water activities causing the spoiling of low and intermediate moisture foods, stored goods and animal feeds, with the consequent economic losses. The combined effect of water activity and temperature of four Eurotium species isolated from animal feeds was investigated. Eurotium amstelodami, Eurotium chevalieri, Eurotium repens and Eurotium rubrum were grown at 5, 15, 25, 37 and 45°C on malt extract agar adjusted with glycerol in the range 0.710-0.993 of water activities. The cardinal model proposed by Rosso and Robinson (2001) was applied to fit growth data, with the variable water activity at fixed temperatures, obtaining three cardinal water activities (a wmin , a wmax , a wopt ) and the specific growth rate at the optimum a w (μ opt ). A probabilistic model was also applied to define the interface between growth and no-growth. The cardinal model provided an adequate estimation of the optimal a w to grow and the maximum growth rate. The probabilistic model showed a good performance to fit growth/no-growth cases in the predicted range. The results presented here could be applied to predict Eurotium species growth in animal feeds. Copyright © 2017 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. An Active-Distributed Temperature Sensing method to quantify groundwater - surface water exchanges

    Science.gov (United States)

    Simon, Nataline; Bour, Olivier; Lavenant, Nicolas; Faucheux, Mickaël; Fovet, Ophélie; Longuevergne, Laurent

    2017-04-01

    Understanding and quantifying groundwater and surface water interactions are key elements for the management of water quality and quantity, but also for the preservation of groundwater dependent ecosystems and riparian habitat. We developed a methodology to quantify groundwater and surface water interactions, by setting up an active heat tracer experiment using fiber-optic distributed temperature sensing (FO-DTS). The experimental setup consists in heating an armoured fiber-optic cable that has been previously deployed along the streambed within the sediments. Then, the increase in temperature along the heated cable is a function of the thermal properties of the sediments and of the fluid flow velocity within the sediments. The cable is heated electrically through the steel armouring of the cable while the elevations in temperature are continuously monitored. We tested this methodology on the Kerbernez catchment, located in south-western Brittany (France) and which is part of the AgrHys hydrological observatory. We deploy the cable in a first-order stream within this small agricultural catchment (0.12 km2). Temperature was monitored along 60 meters of stream with a spatial and temporal resolution respectively equal to 29 cm and 30 s. To interpret the data, we used an analytical solution developed for geothermal energy that considers advection and conduction of temperature in porous media. To validate the use of the analytical solution and to define the limits of the method, a 2D numerical model has been developed. This model simulates heat transport and conduction with steady state fluid flow using the Conjugate Heat Transfer module of COMSOL Multiphysics ®. During heating and cooling, the measured temperature was particularly variable along the section with temperature increases that range between 16 to 36°C. This variability can directly be associated with local variations of water fluxes by applying the appropriate analytical solution. Henceforth, it is

  11. Influence of water activity, temperature and time on mycotoxins production on barley rootlets.

    Science.gov (United States)

    Ribeiro, J M M; Cavaglieri, L R; Fraga, M E; Direito, G M; Dalcero, A M; Rosa, C A R

    2006-02-01

    The objective of this study was to determine the ochratoxin (OT) and aflatoxin (AF) production by three strains of Aspergillus spp. under different water activities, temperature and incubation time on barley rootlets (BR). Aspergillus ochraceus and Aspergillus flavus were able to produce mycotoxins on BR. Aspergillus ochraceus produced ochratoxin A (OTA) at 0.80 water activity (a(w)), at 25 and 30 degrees C as optimal environmental conditions. The OTA production varies at different incubation days depending on a(w). Aflatoxin B(1) (AFB1) accumulation was obtained at 25 degrees C, at 0.80 and 0.95 a(w), after 14 and 21 incubation days respectively. Temperature was a critical factor influencing OTA and AFB(1) production. This study demonstrates that BR support OTA and AFB(1) production at relatively low water activity (0.80 a(w)) and high temperatures (25-30 degrees C). The study of ecophysiological parameters and their interactions would determine the prevailing environmental factors, which enhance the mycotoxin production on BR used as animal feed.

  12. Modeling the influence of temperature, water activity and water mobility on the persistence of Salmonella in low-moisture foods.

    Science.gov (United States)

    Farakos, S M Santillana; Frank, J F; Schaffner, D W

    2013-09-02

    Salmonella can survive in low-moisture foods for long periods of time. Reduced microbial inactivation during heating is believed to be due to the interaction of cells and water, and is thought to be related to water activity (a(w)). Little is known about the role of water mobility in influencing the survival of Salmonella in low-moisture foods. The aim of this study was to determine how the physical state of water in low-moisture foods influences the survival of Salmonella and to use this information to develop mathematical models that predict the behavior of Salmonella in these foods. Whey protein powder of differing water mobilities was produced by pH adjustment and heat denaturation, and then equilibrated to aw levels between 0.19±0.03 and 0.54±0.02. Water mobility was determined by wide-line proton-NMR. Powders were inoculated with a four-strain cocktail of Salmonella, vacuum-sealed and stored at 21, 36, 50, 60, 70 and 80°C. Survival data was fitted to the log-linear, the Geeraerd-tail, the Weibull, the biphasic-linear and the Baranyi models. The model with the best ability to describe the data over all temperatures, water activities and water mobilities (f(test)survival kinetics for Salmonella. The influence of temperature, aw and water mobility on the survival of Salmonella was evaluated using multiple linear regression. Secondary models were developed and then validated in dry non-fat dairy and grain, and low-fat peanut and cocoa products within the range of the modeled data. Water activity significantly influenced the survival of Salmonella at all temperatures, survival increasing with decreasing a(w). Water mobility did not significantly influence survival independent of a(w). Secondary models were useful in predicting the survival of Salmonella in various low-moisture foods providing a correlation of R=0.94 and an acceptable prediction performance of 81%. The % bias and % discrepancy results showed that the models were more accurate in predicting

  13. Combined effects of water temperature and copper ion concentration on catalase activity in Crassostrea ariakensis

    Science.gov (United States)

    Wang, Hui; Yang, Hongshuai; Liu, Jiahui; Li, Yanhong; Liu, Zhigang

    2015-07-01

    A central composite experimental design and response surface method were used to investigate the combined effects of water temperature (18-34°C) and copper ion concentration (0.1-1.5 mg/L) on the catalase (CAT) activity in the digestive gland of Crassostrea ariakensis. The results showed that the linear effects of temperature were significant ( P0.05), and the quadratic effects of copper ion concentration were significant ( P0.05), and the effect of temperature was greater than that of copper ion concentration. A model equation of CAT enzyme activity in the digestive gland of C. ariakensis toward the two factors of interest was established, with R 2, Adj. R 2 and Pred. R 2 values as high as 0.943 7, 0.887 3 and 0.838 5, respectively. These findings suggested that the goodness of fit to experimental data and predictive capability of the model were satisfactory, and could be practically applied for prediction under the conditions of the study. Overall, the results suggest that the simultaneous variation of temperature and copper ion concentration alters the activity of the antioxidant enzyme CAT by modulating active oxygen species metabolism, which may be utilized as a biomarker to detect the effects of copper pollution.

  14. Low-temperature activation of hematite nanowires for photoelectrochemical water oxidation.

    Science.gov (United States)

    Ling, Yichuan; Wang, Gongming; Wang, Hanyu; Yang, Yi; Li, Yat

    2014-03-01

    Hematite (α-Fe2 O3 ) nanostructures have been extensively studied as photoanode materials for photoelectrochemical (PEC) water oxidation. However, the photoactivity of pristine hematite nanostructures is fairly low and typically requires thermal activation at temperature of 650 °C or above. Here, we report a new method for enhancing the photocurrent of hematite nanowires at a substantially lower temperature of 350 °C by means of a two-step annealing process (activation process). Hydrothermally grown β-FeOOH nanowires were first annealed in a pure N2 environment at 350 °C to form magnetite, followed by partial oxidation in air to convert magnetite to hematite. During this process, Fe(2+) sites (oxygen vacancies) were intentionally created to increase the donor density and therefore the electrical conductivity of hematite. The oxygen-deficient hematite nanowire photoanode created at low temperature (350 °C) show considerably enhanced photoactivity compared to pristine hematite sample that prepared by thermal annealing of β-FeOOH nanowires at 550 °C in air. Moreover, this low-temperature annealing method can be coupled with an element doping method to further increase the photoactivity of hematite nanowire. Sn-doped hematite nanowires prepared by the same low-temperature annealing method show at least three fold enhanced photocurrent compared to the undoped sample. Significantly, the highest temperature in the entire annealing process was 350 °C, which is the lowest activation temperature ever reported for hematite nanowire photoanodes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Modeling the effect of water activity and storage temperature on chemical stability of coffee brews.

    Science.gov (United States)

    Manzocco, Lara; Nicoli, Maria Cristina

    2007-08-08

    This work was addressed to study the chemical stability of coffee brew derivatives as a function of water activity (aw) and storage temperature. To this purpose, coffee brew was freeze-dried, equilibrated at increasing aw values, and stored for up to 10 months at different temperatures from -30 to 60 degrees C. The chemical stability of the samples was assessed by measuring H3O+ formation during storage. Independently of storage temperature, the rate of H3O+ formation was considerably low only when aw was reduced below 0.5 (94% w/w). Beyond this critical boundary, the rate increased, reaching a maximum value at ca. 0.8 aw (78% w/w). Further hydration up to the aw of the freshly prepared beverage significantly increased chemical stability. It was suggested that mechanisms other than lactones' hydrolysis, probably related to nonenzymatic browning pathways, could contribute to the observed increase in acidity during coffee staling. The temperature dependence of H3O+ formation was well-described by the Arrhenius equation in the entire aw range considered. However, aw affected the apparent activation energy and frequency factor. These effects were described by simple equations that were used to set up a modified Arrhenius equation. This model was validated by comparing experimental values, not used to generate the model, with those estimated by the model itself. The model allowed efficient prediction of the chemical stability of coffee derivatives on the basis of only the aw value and storage temperature.

  16. Bactericidal Effects against S. aureus and Physicochemical Properties of Plasma Activated Water stored at different temperatures

    Science.gov (United States)

    Shen, Jin; Tian, Ying; Li, Yinglong; Ma, Ruonan; Zhang, Qian; Zhang, Jue; Fang, Jing

    2016-01-01

    Water activated by non-thermal plasma creates an acidified solution containing reactive oxygen and nitrogen species, known as plasma-activated water (PAW). The objective of this study was to investigate the effects of different storage temperatures (25 °C, 4 °C, −20 °C, −80 °C) on bactericidal activities against S. aureus and physicochemical properties of PAW up to 30 days. Interestingly, PAW stored at −80 °C yielded the best antibacterial activity against Staphylococcus aureus, 3~4 log reduction over a 30-day period after PAW generation; meanwhile, PAW stored at 25 °C, 4 °C, and −20 °C, respectively, yielded 0.2~2 log decrease in cell viability after the same exposure and storage time. These results were verified by scanning electron microscope (SEM). The physicochemical properties of PAW stored at different temperatures were evaluated, including pH, oxidation reduction potential (ORP), and hydrogen peroxide, nitrate, nitrite anion and NO radical levels. These findings suggested that bacterial activity of PAW stored at 25 °C, 4 °C, −20 °C decreased over time, and depended on three germicidal factors, specifically ORP, H2O2, and NO3−. Moreover, PAW stored at −80 °C retained bactericidal activity, with NO2− contributing to bactericidal ability in association with H2O2. Our findings provide a basis for PAW storage and practical applications in disinfection and food preservation. PMID:27346695

  17. Effect of water activity and temperature on competing abilities of common postharvest citrus fungi.

    Science.gov (United States)

    Plaza, Pilar; Usall, Josep; Teixidó, Neus; Viñas, Immaculada

    2004-01-01

    The effect of temperature (4-30 degrees C) and water activity (a(w), 0.995-0.90) on the 'in vitro' interactions between Penicillium digitatum, Penicillium italicum and Geotrichum candidum were evaluated. The effect of temperature on growth of green and blue mould decays and their interactions on wounded oranges was also studied. The major competing abilities were observed at optimal conditions of temperature and a(w) for growth (25 degrees C and 0.995 a(w)), and no differences between growth rates when the fungi were growing alone or paired were observed in the other studied conditions. P. italicum and G. candidum were able to reduce the growth rate of P. digitatum when it was growing paired 'in vitro', suggesting that inhibitory metabolites were produced. In the 'in vivo' assays, growth rates of green mould were higher than those of blue mould at any temperature studied. However, at 4 degrees C, P. italicum began its rot development 1 week before P. digitatum. When these two pathogens were inoculated into the same wound at 25 degrees C, blue mould was practically inhibited. The difference between the results obtained in 'in vitro' and 'in vivo' assays suggests that other factors could interact with fungi, favoring the development of one pathogen to the detriment of the others.

  18. Effect of water activity and temperature on the stability of creatine during storage.

    Science.gov (United States)

    Uzzan, Michael; Nechrebeki, Jacob; Zhou, Peng; Labuza, Theodore P

    2009-08-01

    Creatine degradation to creatinine, which has no biological activity, in combinations of glycerol and pH 4.0 buffer solutions followed first-order kinetics up to a point where degradation started to level off, generally beyond the first half-life. Practical data are reported for a wide range of water activity (a(w)) values (0.31-0.983) at 4 degrees C, 23 degrees C, and 35 degrees C. Creatine degradation did not exhibit a dilution effect, that is a decrease in rate about an a(w) of 0.7, as is found for both microbiological growth and chemical reactions in semisolid food matrix systems. The temperature dependence obeyed the Arrhenius relationship with an energy of activation of about 20 kcal/mol at a(w) >or= 0.68 increasing to 23 kcal/mole below that a(w). In addition, a semilog plot of half-life as a function of a(w) at each temperature follows a predicted straight line. The pH and assumed liquid viscosity increase through increased glycerol concentration were not able to completely explain the decrease in rate of degradation as a function of a(w). Furthermore, we confirmed that creatine stability in the crystal form is very high as long as it does not reach the deliquescence state.

  19. Salmonella Survival Kinetics on Pecans, Hazelnuts, and Pine Nuts at Various Water Activities and Temperatures.

    Science.gov (United States)

    Santillana Farakos, Sofia; Pouillot, Régis; Keller, Susanne E

    2017-04-17

    The impact of temperature, water activity (a w ), and nut composition on Salmonella survival on tree nuts has not been thoroughly examined. The aim of this study was to determine the effect of temperature, a w , and nut composition on the survival of Salmonella on tree nuts and develop predictive models. Pecans, hazelnuts, and pine nuts were chosen based on differences in their typical fat content. Nuts were inoculated with a cocktail of five Salmonella serotypes (11 log CFU/mL) and then were dried and stored at 4, 10, and 25°C at 0.41 ± 0.06 and 0.60 ± 0.05 a w for 1 year. Ten-gram quantities were removed at different intervals up to 364 days to test for surviving Salmonella populations (plating on selective and nonselective media) and a w . Experiments were carried out in triplicate. Salmonella populations were relatively stable over a year at 4 and 10°C at both a w levels with Salmonella survival at 4 and 10°C was a log-linear model with a D-value for each tree nut and a w combination. Significant declines in Salmonella levels were observed at 25°C, where the best fit was a Weibull model with a fixed ρ for all tree nuts (ρ = 0.86), a δ value for each tree nut and a w combination, and a random factor to account for variability among replicates. The time for the first log reduction at 25°C and 0.37 ± 0.009 a w was estimated at 24 ± 2 weeks for hazelnuts, 34 ± 3 weeks for pecans, and 52 ± 7 weeks for pine nuts. At the same temperature, but with 0.54 ± 0.009 a w , the mean estimated time for the first log reduction decreased to 9 ± 1 weeks for hazelnuts, 10 ± 1 weeks for pecans, and 16 ± 1 weeks for pine nuts. Tree nut, a w , and temperature were shown to have a statistically significant effect on survival (P survival was observed. The results of this study can be used to predict changes in Salmonella levels on pecans, hazelnuts, and pine nuts after storage at the different temperatures and a w values.

  20. Survival of bacteria in nuclear waste buffer materials. The influence of nutrients, temperature and water activity

    Energy Technology Data Exchange (ETDEWEB)

    Pedersen, K.; Motamedi, M. [Goeteborg Univ. (Sweden). Dept. of General and Marine Microbiology; Karnland, O. [Clay Technology AB, Lund (Sweden)

    1995-12-01

    The concept of deep geological disposal of spent fuel is common to many national nuclear waste programs. Long-lived radioactive waste will be encapsulated in canisters made of corrosion resistant materials e.g. copper and buried several hundred meters below ground in a geological formation. Different types of compacted bentonite clay, or mixtures with sand, will be placed as a buffer around the waste canisters. A major concern for the performance of the canisters is that sulphate-reducing bacteria (SRB) may be present in the clay and induce corrosion by production of hydrogen sulphide. This report presents data on viable counts of SRB in the bedrock of Aespoe hard rock laboratory. A theoretical background on the concept water activity is given, together with basic information about SRB. Some results on microbial populations from a full scale buffer test in Canada is presented. These results suggested water activity to be a strong limiting factor for survival of bacteria in compacted bentonite. As a consequence, experiments were set up to investigate the effect from water activity on survival of SRB in bentonite. Here we show that survival of SRB in bentonite depends on the availability of water and that compacting a high quality bentonite to a density of 2.0 g/cm{sup 3}, corresponding to a water activity (a{sub w}) of 0.96, prevented SRB from surviving in the clay. 24 refs.

  1. Influence of water temperature on acetylcholinesterase activity in the pacific tree frog (Hyla regilla)

    Science.gov (United States)

    Johnson, Catherine S.; Schwarzbach, Steven E.; Henderson, John D.; Wilson, Barry W.; Tjeerdema, Ronald S.

    2005-01-01

    This investigation evaluated whether acetylcholinesterase (AChE) in Pacific tree frogs (Hyla regilla) from different geographical locations was influenced by different temperatures during early aquatic life stages, independent of pesticide exposure. Tadpoles were collected from both a California coastal pond and a Sierra Nevada mountain range pond, USA. Groups of frogs from each location were raised in temperatures representative of either the Sierra Nevada (8°C) or the coastal (19°C) location. Metamorphs from both locations raised as tadpoles at 19°C had AChE activities of 42.3 and 38.7 nm/min/mg protein, while those raised as tadpoles at 8°C had activities of 26.9 and 28.2 nm/min/mg protein. A two-way analysis of variance revealed temperature to be the significant factor in determining AChE activity (F = 22.3, p tree frogs must consider the influence of environmental temperature to enable cross-population comparisons.

  2. Carbon Dioxide Mediates the Response to Temperature and Water Activity Levels in Aspergillus flavus during Infection of Maize Kernels

    Directory of Open Access Journals (Sweden)

    Matthew K. Gilbert

    2017-12-01

    Full Text Available Aspergillus flavus is a saprophytic fungus that may colonize several important crops, including cotton, maize, peanuts and tree nuts. Concomitant with A. flavus colonization is its potential to secrete mycotoxins, of which the most prominent is aflatoxin. Temperature, water activity (aw and carbon dioxide (CO2 are three environmental factors shown to influence the fungus-plant interaction, which are predicted to undergo significant changes in the next century. In this study, we used RNA sequencing to better understand the transcriptomic response of the fungus to aw, temperature, and elevated CO2 levels. We demonstrate that aflatoxin (AFB1 production on maize grain was altered by water availability, temperature and CO2. RNA-Sequencing data indicated that several genes, and in particular those involved in the biosynthesis of secondary metabolites, exhibit different responses to water availability or temperature stress depending on the atmospheric CO2 content. Other gene categories affected by CO2 levels alone (350 ppm vs. 1000 ppm at 30 °C/0.99 aw, included amino acid metabolism and folate biosynthesis. Finally, we identified two gene networks significantly influenced by changes in CO2 levels that contain several genes related to cellular replication and transcription. These results demonstrate that changes in atmospheric CO2 under climate change scenarios greatly influences the response of A. flavus to water and temperature when colonizing maize grain.

  3. Combined effect of storage temperature and water activity on the antiglycoxidative properties and color of dehydrated apples.

    Science.gov (United States)

    Lavelli, Vera

    2009-12-23

    Phytochemical contents, color, and inhibition efficacy toward oxidative and glycoxidative reactions were studied in dehydrated apples following storage in the water activity range from 0.1 to 0.7 at 20, 30, and 40 degrees C, which can be considered as room conditions. Hunter colorimetric parameters were analyzed at different temperatures and time intervals, and nonenzymatic browning was modeled according to pseudo-zero-order kinetics. The effect of temperature on the browning rate followed the Arrhenius equation, with an activation energy of 64000 J/mol, which was not affected by the water activity level. The phytochemical contents, inhibition efficacy of protein glycation, and antioxidant properties were then analyzed in the products stored under selected "equivalent" conditions in terms of browning effects, namely, 120 days/20 degrees C, 50 days/30 degrees C, and 22 days/40 degrees C. After storage for 120 days/20 degrees C, the retention percentages of hydroxycinnamic acids, phloridzin, and epicatechin were >86%, but ascorbic acid, catechin, and procyanidins were less stable; concurrently dehydrated apples retained about 80% of the radical scavenging activity and 70% of the ability to inhibit protein glycation. Following storage at higher temperatures the expected browning effect occurred in a shorter time scale; however, the patterns of product degradation were different. A sharp increase in the degradation rates of all antioxidants, relative to browning rate, was observed at temperatures >or=30 degrees C, and this trend was accelerated with concurrent increase in water activity at >0.3 levels. The application of low-temperature/long-time conditions for storage of dehydrated apples corresponded to maximum retention of their efficacy to counteract oxidative and glycoxidative reactions, which have been linked to human chronic diseases.

  4. Interacting effects of water temperature and swimming activity on body composition and mortality of fasted juvenile rainbow trout

    Science.gov (United States)

    Simpkins, D.G.; Hubert, W.A.; Martinez Del Rio, C.; Rule, D.C.

    2003-01-01

    Abstract: We assessed changes in proximate body composition, wet mass, and the occurrence of mortality among sedentary and actively swimming (15 cm/s) juvenile rainbow trout (Oncorhynchus mykiss) (120-142 mm total length) that were held at 4.0, 7.5, or 15.0 ??C and fasted for 140 days. Warmer water temperatures and swimming activity accentuated declines in lipid mass, but they did not similarly affect lean mass and wet mass. Swimming fish conserved lean mass independent of water temperature. Because lean mass exceeded lipid mass, wet mass was not affected substantially by decreases in lipid mass. Consequently, wet mass did not accurately reflect the effects that water temperature and swimming activity had on mortality of fasted rainbow trout. Rather, lipid mass was more accurate in predicting death from starvation. Juvenile rainbow trout survived long periods without food, and fish that died of starvation appeared to have similar body composition. It appears that the ability of fish to endure periods without food depends on the degree to which lipid mass and lean mass can be utilized as energy sources.

  5. Temperature dependence of the infinite dilution activity coefficient and Henry's law constant of polycyclic aromatic hydrocarbons in water.

    Science.gov (United States)

    Reza, Joel; Trejo, Arturo

    2004-08-01

    The water solubility of 9,10-dihydroanthracene was experimentally determined between 278.12 and 313.17 K. Determinations were carried out by an experimental procedure developed in our laboratory, which is a modification of the dynamic coupled column liquid chromatographic technique. The uncertainty of the experimental determinations ranged from +/- 0.50% to +/- 3.10%. These data, as well as the water solubility data of other five polycyclic aromatic hydrocarbons (PAHs) previously studied, were used to calculate the temperature dependence of the infinite dilution activity coefficient of 9,10-dihydroanthracene, anthracene, pyrene, 9,10-dihydrophenanthrene, m-terphenyl, and guaiazulene in water. Molar excess enthalpies and entropies at infinite dilution, at 298.15 K, were also derived. The temperature dependence of the infinite dilution activity coefficients was used, together with literature values of the vapor pressures of supercooled liquid PAHs (p(B)(sc)), to estimate their Henry's law constants (HLC). Only HLC for anthracene, pyrene, and 9,10-dihydrophenanthrene were calculated, since no p(B)(sc) data were available in the literature for 9,10-dihydroanthracene, m-terphenyl, and guaiazulene. From the observed temperature dependence of the Henry's law constants the enthalpy and entropy of the phase change from the dissolved phase to the gas phase were also derived for anthracene, pyrene, and 9,10-dihydrophenanthrene.

  6. Water activity and temperature effects on growth of Eurotium amstelodami, E. chevalieri and E. herbariorum on a sponge cake analogue.

    Science.gov (United States)

    Abellana, M; Magrí, X; Sanchis, V; Ramos, A J

    1999-11-01

    Eurotium is a widespread storage fungal genus that has been frequently isolated from bakery products. The objective of this study was (i) to obtain a method for studying the growth of xerophilic fungi on bakery products, and (ii) to determine the effects of water activity (a(w)), temperature, isolate and their interactions on mycelial growth of Eurotium spp. on an analogue medium of sponge cake. Statistical analysis showed that there were intra-isolate differences (P<0.001) due to a(w), temperature, isolate, and two- and three-way interactions. Optimum growth of all isolates over a(w) x temperature range tested showed optima at 0.90 a(w) and 30 degrees C, with an interval of growth rate of 3.8-5.1 mm x d(-1). At 0.75 a(w), growth was less than 0.15 mm x d(-1), if there was any.

  7. Effective Energy Transfer via Plasmon-Activated High-Energy Water Promotes Its Fundamental Activities of Solubility, Ionic Conductivity, and Extraction at Room Temperature

    Science.gov (United States)

    Yang, Chih-Ping; Chen, Hsiao-Chien; Wang, Ching-Chiung; Tsai, Po-Wei; Ho, Chia-Wen; Liu, Yu-Chuan

    2015-12-01

    Water is a ubiquitous solvent in biological, physical, and chemical processes. Unique properties of water result from water’s tetrahedral hydrogen-bonded (HB) network (THBN). The original THBN is destroyed when water is confined in a nanosized environment or localized at interfaces, resulting in corresponding changes in HB-dependent properties. In this work, we present an innovative idea to validate the reserve energy of high-energy water and applications of high-energy water to promote water’s fundamental activities of solubility, ionic conductivity, and extraction at room temperature. High-energy water with reduced HBs was created by utilizing hot electrons with energies from the decay of surface plasmon excited at gold (Au) nanoparticles (NPs). Compared to conventional deionized (DI) water, solubilities of alkali metal-chloride salts in high-energy water were significantly increased, especially for salts that release heat when dissolved. The ionic conductivity of NaCl in high-energy water was also markedly higher, especially when the electrolyte’s concentration was extremely low. In addition, antioxidative components, such as polyphenols and 2,3,5,4’-tetrahydroxystilbene-2-O-beta-d-glucoside (THSG) from teas, and Polygonum multiflorum (PM), could more effectively be extracted using high-energy water. These results demonstrate that high-energy water has emerged as a promising innovative solvent for promoting water’s fundamental activities via effective energy transfer.

  8. Modeling growth of three bakery product spoilage molds as a function of water activity, temperature and pH.

    Science.gov (United States)

    Dagnas, Stéphane; Onno, Bernard; Membré, Jeanne-Marie

    2014-09-01

    The objective of this study was to quantify the effect of water activity, pH and storage temperature on the growth of Eurotium repens, Aspergillus niger and Penicillium corylophilum, isolated from spoiled bakery products. Moreover, the behaviors of these three mold species were compared to assess whether a general modeling framework may be set and re-used in future research on bakery spoilage molds. The mold growth was modeled by building two distinct Gamma-type secondary models: one on the lag time for growth and another one on the radial growth rate. A set of 428 experimental growth curves was generated. The effect of temperature (15-35 °C), water activity (0.80-0.98) and pH (3-7) was assessed. Results showed that it was not possible to apply the same set of secondary model equations to the three mold species given that the growth rate varied significantly with the factors pH and water activity. In contrast, the temperature effect on both growth rate and lag time of the three mold species was described by the same equation. The equation structure and model parameter values of the Gamma models were also compared per mold species to assess whether a relationship between lag time and growth rate existed. There was no correlation between the two growth responses for E. repens, but a slight one for A. niger and P. corylophilum. These findings will help in determining bakery product shelf-life and guiding future work in the predictive mycology field. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Influence of water activity and temperature on growth and mycotoxin production by Alternaria alternata on irradiated soya beans.

    Science.gov (United States)

    Oviedo, Maria Silvina; Ramirez, Maria Laura; Barros, Germán Gustavo; Chulze, Sofia Noemi

    2011-09-15

    The aim of this study was to determine the effects of water activity (a(w)) (0.99-0.90), temperature (15, 25 and 30°C) and their interactions on growth and alternariol (AOH) and alternariol monomethyl ether (AME) production by Alternaria alternata on irradiated soya beans. Maximum growth rates were obtained at 0.980 a(w) and 25°C. Minimum a(w) level for growth was dependent on temperature. Both strains were able to grow at the lowest a(w) assayed (0.90). Maximum amount of AOH was produced at 0.98 a(w) but at different temperatures, 15 and 25°C, for the strains RC 21 and RC 39 respectively. Maximum AME production was obtained at 0.98 a(w) and 30°C for both strains. The concentration range of both toxins varied considerably depending on a(w) and temperature interactions. The two metabolites were produced over the temperature range 15 to 30°C and a(w) range 0.99 to 0.96. The limiting a(w) for detectable mycotoxin production is slightly greater than that for growth. Two-dimensional profiles of a(w)× temperature were developed from these data to identify areas where conditions indicate a significant risk from AOH and AME accumulation on soya bean. Knowledge of AOH and AME production under marginal or sub-optimal temperature and a(w) conditions for growth can be important since improper storage conditions accompanied by elevated temperature and moisture content in the grain can favour further mycotoxin production and lead to reduction in grain quality. This could present a hazard if the grain is used for human consumption or animal feedstuff. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Influence of temperature and water activity on growth and patulin production by Byssochlamys nivea in apple juice.

    Science.gov (United States)

    Roland, J O; Beuchat, L R

    1984-01-01

    The influence of temperature and water activity (aw) on growth and patulin production by Byssochlamys nivea in apple syrups was determined over a 44-day incubation period. The minimum aw at which the mold was capable of growing was 0.915 and 0.886 at 21 and 30 degrees C, respectively. Growth at 37 degrees C was observed at 0.871 aw. Minimum aw values for patulin production were 0.978, 0.968, and 0.959 at 21, 30 and 37 degrees C, respectively. PMID:6696417

  11. Mould contamination and the influence of water activity and temperature on mycotoxin production by two aspergilli in melon seed.

    Science.gov (United States)

    Adebajo, L O; Bamgbelu, O A; Olowu, R A

    1994-01-01

    Both the moisture levels and the incidence of mould contamination recorded for shelled water melon seed samples (22) obtained from 9 markets were generally higher as those recorded for the unshelled seed samples. 16 fungi, mostly toxigenic, were isolated from the surface-disinfected mouldy seeds. Of these isolates, 7, 3 and 2 species belonged to Aspergillus, Penicillum and Fusarium genera, respectively, while Botryodiplodia, Rhizopus, Sclerotium and Syncephalastrum had one representative each. Production of aflatoxins (B1, B2) by 5 toxigenic strains of Aspergillus flavus and of ochratoxin A by 4 toxigenic strains of A. ochraceus in melon seed at varying water activity (aw) and temperature levels were investigated. Of the aw levels (0.65, 0.70, 0.80, 0.90 and 0.98) provided, toxins were detected only at and above 0.80 with the peak production recorded at either 0.90 or 0.98 aw level. Whereas aflatoxins were produced and detected under all the test temperatures (15, 20, 25, 30, 35, and 40 degrees C), the elaboration of ochratoxin A was detected only as from 25 to 40 degrees C. Optimum temperature for toxin production by all the strains of the two fungi used was 30 degrees C.

  12. Ammonium removal of drinking water at low temperature by activated carbon filter biologically enhanced with heterotrophic nitrifying bacteria.

    Science.gov (United States)

    Qin, Wen; Li, Wei-Guang; Zhang, Duo-Ying; Huang, Xiao-Fei; Song, Yang

    2016-03-01

    We sought to confirm whether use of Acinetobacter strains Y7 and Y16, both strains of heterotrophic nitrifying bacteria, was practical for removing ammonium (NH4 (+)-N) from drinking water at low temperatures. To test this, ammonium-containing drinking water was treated with strains Y7 and Y16 at 8 and 2 °C. Continuous ammonium treatment was conducted in order to evaluate the performance of three biologically enhanced activated carbon (BEAC) filters in removing ammonium. The three BEAC filters were inoculated with strain Y7, strain Y16, and a mixture of strains Y7 and Y16, respectively. A granular activated carbon (GAC) filter, without inoculation by any strains, was tested in parallel with the BEAC filters as control. The results indicated that NH4 (+)-N removal was significant when a BEAC filter was inoculated with the mixture of strains Y7 and Y16 (BEAC-III filter). Amounts of 0.44 ± 0.05 and 0.25 ± 0.05 mg L(-1) NH4 (+)-N were removed using the BEAC-III filter at 8 and 2 °C, respectively. These values were 2.8-4.0-fold higher than the values of ammonium removal acquired using the GAC filter. The synergistic effect of using strains Y7 and Y16 in concert was the cause of the high-ammonium removal efficiency achieved by using the BEAC-III filter at low temperatures. In addition, a high C/N ratio may promote NH4 (+)-N removal efficiency by improving biomass and microbial activity. This study provides new insight into the use of biofilters to achieve biological removal of ammonium at low temperature.

  13. Effect of water activity and temperature on germination and growth of Penicillium digitatum, P. italicum and Geotrichum candidum.

    Science.gov (United States)

    Plaza, P; Usall, J; Teixidó, N; Viñas, I

    2003-01-01

    This study compares the effect of temperature (4-37 degrees C) and water activity (aw: 0.99-0.87) and their interactions on the germination rates, lag times prior to germination and mycelial growth 'in vitro' of Penicillium digitatum, P. italicum and Geotrichum candidum, the main postharvest pathogens affecting citrus fruits. Germination and growth were markedly influenced by temperature and aw. Generally, lag times were longer and germination and growth rates were slower when conditions of temperature and aw were far from optimum. All the studied species were able to germinate over a range of 4-30 degrees C at 0.995 aw, although in non-optimal conditions P. digitatum only reached 40-60% of germinated conidia. At low temperatures, P. italicum germinated and grew faster than P. digitatum and G. candidum, particularly at 0.95 aw. Penicillium italicum was also able to germinate and grow in the driest studied conditions (0.87 aw), while G. candidum did not germinate under 0.95 aw. Knowledge of the ecological requirements of these fungi is important in order to understand their behaviour in natural situations and to predict fungal spoilage on citrus fruits.

  14. Effects of temperature, pH, water activity and CO2 concentration on growth of Rhizopus oligosporus NRRL 2710.

    Science.gov (United States)

    Sparringa, R A; Kendall, M; Westby, A; Owens, J D

    2002-01-01

    To investigate the effects of temperature, pH, water activity (aw) and CO2 concentration on the growth of Rhizopus oligosporus NRRL 2710. Hyphal extension rates from mycelial and spore inocula were measured on media with different aw (approximately 1.0, 0.98 and 0.96) and pH (3.5, 5.5 and 7.5) incubated at 30, 37 or 42 degrees C in atmospheres containing 0.03, 12.5 or 25% (v/v) CO2. The effects of environmental conditions on hyphal extension rate were modelled using surface response methodology. The rate of hyphal extension was very sensitive to pH, exhibiting a pronounced optimum at pH 5.5-5.8. The hyphal extension rate was less sensitive to temperature, aw or CO2, exhibiting maximum rates at 42 degrees C, a(w) approximately 1.0 and 0.03% (v/v) CO2. The fastest hyphal extension rate (1.7 mm h(-1)) was predicted to occur at 42 degrees C, pH 5.85, a(w) approximately 1.0 and 0.03% CO2. The present work is the first to model the simultaneous effects of temperature, pH, aw and CO2 concentration on mould growth. The information relates to tempe fermentation and to possible control of the microflora in Tanzanian cassava heap fermentations.

  15. Modelling water temperature in TOXSWA

    NARCIS (Netherlands)

    Jacobs, C.M.J.; Deneer, J.W.; Adriaanse, P.I.

    2010-01-01

    A reasonably accurate estimate of the water temperature is necessary for a good description of the degradation of plant protection products in water which is used in the surface water model TOXSWA. Based on a consideration of basic physical processes that describe the influence of weather on the

  16. The Low-Temperature Conversion of Methane to Methanol on CeOx/Cu2O catalysts: Water Controlled Activation of the C-H Bond.

    Science.gov (United States)

    Zuo, Zhijun; Ramirez, Pedro J; Senanayake, Sanjaya; Liu, Ping; Rodriguez, Jose A

    2016-10-10

    An inverse CeO2/Cu2O/Cu(111) catalyst is able to activate methane at room temperature producing C, CHx fragments and COx species on the oxide surface. The addition of water to the system leads to a drastic change in the selectivity of methane activation yielding only adsorbed CHx fragments. At a temperature of 450 K, in the presence of water, a CH4  CH3OH catalytic transformation occurs with a high selectivity. OH groups formed by the dissociation of water saturate the catalyst surface, removing sites that could decompose CHx fragments, and generating centers on which methane can directly interact to yield methanol.

  17. Inactivation kinetics of invertase in honey and honey-glucose syrup formulations: effects of temperature and water activity.

    Science.gov (United States)

    Sramek, Martin; Woerz, Benjamin; Horn, Helmut; Weiss, Jochen; Kohlus, Reinhard

    2017-03-01

    The high viscosity and stickiness of honey in its natural state causes handling difficulties, therefore the demand for honey powder is continuously increasing. Powder preparation has to be performed gently because of the thermo- and oxidation- sensitive nature of honey. The aim of this study was to determine the degradation of invertase during drying as an indirect measure of the retention of valuable honey nutrients. The reaction kinetics were estimated in polyfloral honey and honey-glucose syrup (GS) formulation and the impact of temperature (40-70°C) and water activity (a w 0.23-0.81) was established. The honey-GS formulation (55:45 w/w) was intended for the preparation of high-grade honey powders using the vacuum-drying method. Invertase inactivation at temperatures below 60°C followed first-order kinetics. At 60°C high dilution (a w 0.81) and at 70°C, heterogeneous inactivation behaviour was observed. The best fit of invertase heterogeneous inactivation kinetic was achieved with the Cerf two-fraction model. The GS addition showed a stabilizing effect on invertase during thermal degradation. The data on invertase inactivation gathered here can be utilized to select optimal parameters for honey vacuum-drying and other thermal processes in order to achieve maximum invertase retention. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  18. Water activity and temperature effects on growth and mycotoxin production by Alternaria alternata strains isolated from Malbec wine grapes.

    Science.gov (United States)

    Prendes, L P; Zachetti, V G L; Pereyra, A; Morata de Ambrosini, V I; Ramirez, M L

    2017-02-01

    To study the effects of water activity (a W ; 0·99, 0·98, 0·97, 0·96 and 0·95), temperature (15, 25 and 30°C), incubation time (7-28 days), and their interactions on mycelial growth and alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) mycotoxin production on a synthetic nutrient (SN) media similar to grape composition by three strains of Alternaria alternata isolated from wine grapes from Argentina. Interacting conditions of a W , temperature and time of incubation were used to examine growth and mycotoxin production. All strains were able to grow at 0·95 a W , but maximum growth rates were obtained at 0·99 a W and 25°C. Maximum levels of AOH, AME and TA were obtained at 0·99 a W and 25°C, but high amounts of TA were also obtained at 0·96 a W and 15 or 30°C. Production of AOH and AME was favoured over TA at 25°C. TA levels were more sustained than AOH and AME. The optimum and marginal conditions for growth and mycotoxin production by A. alternata on a SN media similar to grape composition were in agreement, but certain stressful conditions for growth evaluated also promote mycotoxin production. Temperature and a W conditions that allows growth and mycotoxin production are those normally found during wine grape ripeness in the field. Therefore, efforts should be made to prevent Alternaria presence and mycotoxin production in wine grapes. © 2016 The Society for Applied Microbiology.

  19. Modelling the effect of temperature, water activity and pH on the growth of Serpula lacrymans.

    Science.gov (United States)

    Maurice, S; Coroller, L; Debaets, S; Vasseur, V; Le Floch, G; Barbier, G

    2011-12-01

    To predict the risk factors for building infestation by Serpula lacrymans, which is one of the most destructive fungi causing timber decay in buildings. The growth rate was assessed on malt extract agar media at temperatures between 1.5 and 45°C, at water activity (a(w)) over the range of 0.800-0.993 and at pH ranges from 1.5 to 11.0. The radial growth rate (μ) and the lag phase (λ) were estimated from the radial growth kinetics via the plots radius vs time. These parameters were then modelled as a function of the environmental factors tested. Models derived from the cardinal model (CM) were used to fit the experimental data and allowed an estimation of the optimal and limit values for fungal growth. Optimal growth rate occurred at 20°C, at high a(w) level (0.993) and at a pH range between 4.0 and 6.0. The strain effect on the temperature parameters was further evaluated using 14 strains of S. lacrymans. The robustness of the temperature model was validated on data sets measured in two different wood-based media (Quercus robur L. and Picea abies). The two-step procedure of exponential model with latency followed by the CM with inflection gives reliable predictions for the growth conditions of a filamentous fungus in our study. The procedure was validated for the study of abiotic factors on the growth rate of S. lacrymans. This work describes the usefulness of evaluating the effect of physico-chemical factors on fungal growth in predictive building mycology. Consequently, the developed mathematical models for predicting fungal growth on a macroscopic scale can be used as a tool for risk assessment of timber decay in buildings. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

  20. Temperature-dependent deliquescence relative humidities and water activities using humidity controlled thermogravimetric analysis with application to malonic acid.

    Science.gov (United States)

    Beyer, Keith D; Schroeder, Jason R; Kissinger, Jared A

    2014-04-03

    We utilize a new experimental technique, humidity-controlled thermogravimetric analysis (HTGA), to determine temperature-dependent deliquescence relative humidities (DRH) and to determine the equilibrium concentration of a solution at a given temperature and relative humidity. To that end, we have investigated the malonic acid/water system determining the DRH and concentration/RH relationship in the temperature range 303-278 K. Excellent agreement is found with literature values for the DRH of malonic acid as a function of temperature and for the concentration/RH relationship at several temperatures. Thus, we extend the DRH and concentration/RH relationship to a broader temperature range and are using the HTGA experiments to investigate other organic acids.

  1. Influence of water activity and temperature on growth and fumonisin production by Fusarium proliferatum strains on irradiated wheat grains.

    Science.gov (United States)

    Cendoya, Eugenia; Monge, María Del Pilar; Chiacchiera, Stella Maris; Farnochi, María Cecilia; Ramirez, María Laura

    2018-02-02

    Wheat is the most important cereal consumed by the Argentine population. In previous studies performed in durum and common wheat grains in this country it has been observed fumonisin contamination as well as high incidence of Fusarium proliferatum. Fumonisins are toxic fungal metabolites, and consumption of fumonisin-contaminated maize has been epidemiologically associated with oesophageal cancer and neural tube defects in some human populations. Using irradiated wheat-grains, the effects of abiotic factors, temperature (15, 25, and 30°C) and water activity (a W ; 0.995, 0.98, 0.96, 0.94, 0.92, and 0.88), on mycelial growth and fumonisin biosynthesis were compared for three F. proliferatum strains isolated from wheat grains in Argentina. Although all isolates showed similar profiles of growth, the fumonisin production profiles were slightly different. Maximum growth rates were obtained at the highest a W (0.995) and 25°C, with growth decreasing as the a W of the medium was reduced. Maximum amounts of total fumonisins (FB 1 , FB 2 and FB 3 ) were produced at 0.995 a W and 15°C for 2 strains, and at 25°C and 0.995 a W for the third one. Fumonisins concentrations varied considerably depending on the a W and temperature interactions assayed. Studied strains showed different fumonisin production profiles. Two-dimensional profiles of a W by temperature interactions were developed from these data to identify areas where conditions indicate a significant risk of fumonisins accumulation on wheat. As a result, temperature and a W conditions that resulted in fumonisins production are those found during wheat grain development (especially milk and dough stages) in the field. This is the first study made using irradiated wheat grains and provides useful baseline data on conditions representing a low or a high risk for fumonisins contamination of wheat grains which is of concern because this cereal is destined mainly for human consumption. Copyright © 2017 Elsevier B.V. All

  2. Modeling the Effect of Temperature and Water Activity on the Thermal Resistance of Salmonella Enteritidis PT 30 in Wheat Flour.

    Science.gov (United States)

    Smith, Danielle F; Hildebrandt, Ian M; Casulli, Kaitlyn E; Dolan, Kirk D; Marks, Bradley P

    2016-12-01

    Salmonella continues to be a problem associated with low-moisture foods, particularly given enhanced thermal resistance at lower water activity (aw). However, there is a scarcity of thermal inactivation models accounting for the effect of aw. The objective of this study was to test multiple secondary models for the effect of product (wheat flour) aw on Salmonella enterica Enteritidis phage type 30 thermal resistance. A full-factorial experimental design included three temperatures (75, 80, and 85°C) and four aw values (~0.30, 0.45, 0.60, and 0.70). Prior to isothermal treatment, sample aw was achieved by equilibrating samples in a humidity-controlled conditioning chamber. Two primary models (log linear and Weibull type) and three secondary models (second-order response surface, modified Bigelow type, and combined effects) were evaluated using the corrected Akaike information criterion and root mean squared errors. Statistical analyses of the primary models favored the log-linear model. Incorporating the three secondary models into the log-linear primary model yielded root mean squared errors of 2.1, 0.78, and 0.96 log CFU/g and corrected Akaike information criterion values of 460, -145, and -19 for the response surface, modified Bigelow, and combined-effects models, respectively. The modified Bigelow-type model, which exponentially scaled both temperature and aw effects on thermal inactivation rates, predicted Salmonella lethality significantly better (P Salmonella in low-moisture products and should be appropriately included in thermal inactivation models for these types of systems.

  3. Modeling Growth and Toxin Production of Toxigenic Fungi Signaled in Cheese under Different Temperature and Water Activity Regimes.

    Science.gov (United States)

    Camardo Leggieri, Marco; Decontardi, Simone; Bertuzzi, Terenzio; Pietri, Amedeo; Battilani, Paola

    2016-12-24

    The aim of this study was to investigate in vitro and model the effect of temperature (T) and water activity (aw) conditions on growth and toxin production by some toxigenic fungi signaled in cheese. Aspergillus versicolor, Penicillium camemberti, P. citrinum, P. crustosum, P. nalgiovense, P. nordicum, P. roqueforti, P. verrucosum were considered they were grown under different T (0-40 °C) and aw (0.78-0.99) regimes. The highest relative growth occurred around 25 °C; all the fungi were very susceptible to aw and 0.99 was optimal for almost all species (except for A. versicolor, awopt = 0.96). The highest toxin production occurred between 15 and 25 °C and 0.96-0.99 aw. Therefore, during grana cheese ripening, managed between 15 and 22 °C, ochratoxin A (OTA), penitrem A (PA), roquefortine-C (ROQ-C) and mycophenolic acid (MPA) are apparently at the highest production risk. Bete and logistic function described fungal growth under different T and aw regimes well, respectively. Bete function described also STC, PA, ROQ-C and OTA production as well as function of T. These models would be very useful as starting point to develop a mechanistic model to predict fungal growth and toxin production during cheese ripening and to help advising the most proper setting of environmental factors to minimize the contamination risk.

  4. Modeling Growth and Toxin Production of Toxigenic Fungi Signaled in Cheese under Different Temperature and Water Activity Regimes

    Directory of Open Access Journals (Sweden)

    Marco Camardo Leggieri

    2016-12-01

    Full Text Available The aim of this study was to investigate in vitro and model the effect of temperature (T and water activity (aw conditions on growth and toxin production by some toxigenic fungi signaled in cheese. Aspergillus versicolor, Penicillium camemberti, P. citrinum, P. crustosum, P. nalgiovense, P. nordicum, P. roqueforti, P. verrucosum were considered they were grown under different T (0–40 °C and aw (0.78–0.99 regimes. The highest relative growth occurred around 25 °C; all the fungi were very susceptible to aw and 0.99 was optimal for almost all species (except for A. versicolor, awopt = 0.96. The highest toxin production occurred between 15 and 25 °C and 0.96–0.99 aw. Therefore, during grana cheese ripening, managed between 15 and 22 °C, ochratoxin A (OTA, penitrem A (PA, roquefortine-C (ROQ-C and mycophenolic acid (MPA are apparently at the highest production risk. Bete and logistic function described fungal growth under different T and aw regimes well, respectively. Bete function described also STC, PA, ROQ-C and OTA production as well as function of T. These models would be very useful as starting point to develop a mechanistic model to predict fungal growth and toxin production during cheese ripening and to help advising the most proper setting of environmental factors to minimize the contamination risk.

  5. Impact of different water activities (a w) adjusted by solutes on high pressure high temperature inactivation of Bacillus amyloliquefaciens spores.

    Science.gov (United States)

    Sevenich, Robert; Reineke, Kai; Hecht, Philipp; Fröhling, Antje; Rauh, Cornelia; Schlüter, Oliver; Knorr, Dietrich

    2015-01-01

    Much research has been conducted to comprehend the mechanisms of high pressure (HP) inactivation of spores in aqueous systems but for food model systems these information are scarce. In these systems spores can interact with ingredients which then could possibly lead to retarded or reduced inactivation, which can cause a problem for the sterilization process. The protective mechanism of a reduced a w-value is still unclear. HP processing might prove valuable to overcome protective effects of solutes and achieve shorter process times for sterilization under HP. To gain insight into the underlying mechanisms five a w-values (0.9, 0.92, 0.94, 0.96, 1) were adjusted with two different solutes (NaCl, sucrose). Solutions were inoculated with spores of Bacillus amyloliquefaciens and treated at 105, 110, and 115°C at 600 MPa. Further a thermal inactivation was conducted at the same temperatures for a comparison with the HP data. Afterward, the influence of HP high temperature treatment on the inactivation, the dipicolinic acid (DPA)-release and membrane constitution was assessed by plate count, HPLC and flow cytometry (FCM). The results show that during HP treatments sucrose and salt both have a protective effect, in which the influence of sucrose on the retarded inactivation is higher. The threshold water activities (a w), which is 0.94, here salt and sucrose have a significant influence on the inactivation. The comparison of thermal (105-115°C) and HP and high temperature (600 MPa, 105-115°C) treated samples showed that the time needed to achieve a 4-5 log10 inactivation is reduced from 45 (a w = 1) to 75 (a w = 0.9) min at 105°C to 3 (a w = 1) to 15 (a w = 0.9) minutes at 600 MPa and 105°C. The release of DPA is the rate limiting step of the inactivation and therefore monitoring the release is of great interest. The DPA-release is slowed down in high concentrated solutions (e.g., sucrose, salt) in comparison to a w 1. Since there is a difference in the way the

  6. Thermally activated low temperature creep and primary water stress corrosion cracking of NiCrFe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hall, M.M. Jr.

    1993-10-01

    A phenomenological SCC-CGR model is developed based on an apriori assumption that the SCC-CGR is controlled by low temperature creep (LTC). This mode of low temperature time dependent deformation occurs at stress levels above the athermal flow stress by a dislocation glide mechanism that is thermally activated and may be environmentally assisted. The SCC-CGR model equations developed contain thermal activation parameters descriptive of the dislocation creep mechanism. Thermal activation parameters are obtained by fitting the CGR model to SCC-CGR data obtained on Alloy 600 and Alloy X-750. These SCC-CGR activation parameters are compared to LTC activation parameters obtained from stress relaxation tests. When the high concentration of hydrogen at the tip of an SCC crack is considered, the SCC-CGR activation energies and rate sensitivities are shown to be quantitatively consistent with hydrogen reducing the activation energy and increasing the strain rate sensitivity in LTC stress relaxation tests. Stress dependence of SCC-CGR activation energy consistent with that found for the LTC activation energy. Comparisons between temperature dependence of the SCC-CGR stress sensitivity and LTC stress sensitivity provide a basis for speculation on effects of hydrogen and solute carbon on SCC crack growth rates.

  7. Characterization of Alternaria and Penicillium species from similar substrata based on growth at different temperature, pH and water activity

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Frisvad, Jens Christian

    2002-01-01

    Fifty-eight Alternaria isolates representing 10 species or species-groups and 66 Penicillium isolates representing 18 species were examined for their growth response to the combined effects of water activity, temperature and pH in an extended Central Composite Design. Growth responses were recorded...

  8. Effective Energy Transfer via Plasmon-Activated High-Energy Water Promotes Its Fundamental Activities of Solubility, Ionic Conductivity, and Extraction at Room Temperature

    National Research Council Canada - National Science Library

    Yang, Chih-Ping; Chen, Hsiao-Chien; Wang, Ching-Chiung; Tsai, Po-Wei; Ho, Chia-Wen; Liu, Yu-Chuan

    2015-01-01

    ... conductivity, and extraction at room temperature. High-energy water with reduced HBs was created by utilizing hot electrons with energies from the decay of surface plasmon excited at gold (Au) nanoparticles (NPs...

  9. Effect of temperature and water activity on the production of fumonisins by Aspergillus niger and different Fusarium species

    Directory of Open Access Journals (Sweden)

    Frisvad Jens C

    2009-12-01

    Full Text Available Abstract Background Fumonisins are economically important mycotoxins which until recently were considered to originate from only a few Fusarium species. However recently a putative fumonisin gene cluster was discovered in two different Aspergillus niger strains followed by detection of an actual fumonisin B2 (FB2 production in four strains of this biotechnologically important workhorse. Results In the present study, a screening of 5 A. niger strains and 25 assumed fumonisin producing Fusarium strains from 6 species, showed that all 5 A. niger strains produced FB2 and 23 of 25 Fusarium produced fumonisin B1 and other isoforms (fumonisin B2 and B3. Five A. niger and five Fusarium spp. were incubated at six different temperatures from 15-42°C on Czapek Yeast Agar +5% salt or Potato Dextrose Agar. A. niger had the highest production of FB2 at 25-30°C whereas Fusarium spp. had the maximal production of FB1 and FB2 at 20-25°C. Addition of 2.5-5% NaCl, or 10-20% sucrose increased the FB2 production of A. niger, whereas addition of glycerol reduced FB2 production. All three water activity lowering solutes reduced the fumonisin production of the Fusarium species. Conclusion The present study shows that the regulation of fumonisin production is very different in A. niger and Fusarium, and that food and feeds preserved by addition of sugar or salts may be good substrates for fumonisin B2 production by A. niger.

  10. Modelling global fresh surface water temperature

    NARCIS (Netherlands)

    Beek, L.P.H. van; Eikelboom, T.; Vliet, M.T.H. van; Bierkens, M.F.P.

    2011-01-01

    Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment

  11. Application of Doehlert design to determine the combined effects of temperature, water activity and pH on conidial germination of Penicillium chrysogenum.

    Science.gov (United States)

    Sautour, M; Rouget, A; Dantigny, P; Divies, C; Bensoussan, M

    2001-11-01

    The influence of temperature, water activity and pH on the time necessary for germination of 90% of Penicillium chrysogenum conidia inoculated (T90) was determined. A new experimental device was developed for easy monitoring of the germination process. Experiments were carried out according to a Doehlert matrix at 11-31 degrees C, 0.86-0.98 water activity (a(w)) and pH 3.5-6.5. In these conditions, a second order polynomial relationship between T90 and the environmental factors was established for the different humectants used throughout this study (e.g. glycerol and sorbitol) with regression coefficients close to 0.97. For both humectants, the major effect of temperature and water activity on T90 was highlighted, whereas the effect of pH on T90 in these experimental conditions was not significant. The combined effect of temperature and water activity on T90 was also demonstrated. Both the experimental set-up and the Doehlert matrix were well suited to determine the influence of environmental factors on mould germination.

  12. Life and the outer planets. II. Enzyme activity in ammonia-water systems and other exotic media at various temperatures.

    Science.gov (United States)

    Siegel, S M; Speitel, T W

    1977-01-01

    Enzyme activities are customarily measured in aqueous solutions. Activity and thermodynamic parameters are based upon behavior in these solutions although they in no way represent the highly structured internal surface system of the cell. Actual environmental limits for enzyme action may be greater than generally assumed. Peroxidase, catalase, urease and amylase retain activity in drastically modified aqueous and nonaqueous media, including aprotic solvents. Examples include formic acid, methanol, formamide, nitromethane, 10 M LiCl and 15 M aqueous ammonia. Temperatures as low as 225-233 degrees K permit activity in some media. Ammonia-rich environments are compatible with some forms of terrestrial life. Enzyme activity in these exotic media and conditions is relevant to chemical evolution on Jupiter and similar planetary systems.

  13. Retention of Viability of Salmonella in Sucrose as Affected by Type of Inoculum, Water Activity, and Storage Temperature.

    Science.gov (United States)

    Beuchat, Larry R; Mann, David A; Kelly, Christine A; Ortega, Ynes R

    2017-09-01

    Outbreaks of salmonellosis have been associated with consumption of high-sugar, low-water activity (a w ) foods. The study reported here was focused on determining the effect of storage temperature (5 and 25°C) on survival of initially high and low levels of Salmonella in dry-inoculated sucrose (a w 0.26 ± 0.01 to 0.54 ± 0.01) and wet-inoculated sucrose (a w 0.24 ± 0.01 to 0.44 ± 0.04) over a 52-week period. With the exception of dry-inoculated sucrose at a w 0.26, Salmonella survived for 52 weeks in dry- and wet-inoculated sucrose stored at 5 and 25°C. Retention of viability was clearly favored in sucrose stored at 5°C compared with 25°C, regardless of level or type of inoculum or a w . Survival at 5°C was not affected by a w . Initial high-inoculum counts of 5.18 and 5.25 log CFU/g of dry-inoculated sucrose (a w 0.26 and 0.54, respectively) stored for 52 weeks at 5°C decreased by 0.56 and 0.53 log CFU/g; counts decreased by >4.18 and >4.25 log CFU/g in samples stored at 25°C. Inactivation rates in wet-inoculated sucrose were similar to those in dry-inoculated sucrose; however, a trend toward higher persistence of Salmonella in dry- versus wet-inoculated sucrose suggests there was a higher proportion of cells in the wet inoculum with low tolerance to osmotic stress. Survival patterns were similar in sucrose initially containing a low level of Salmonella (2.26 to 2.91 log CFU/g). The pathogen was recovered from low-inoculated sucrose stored at 5°C for 52 weeks regardless of type of inoculum or a w and from dry-inoculated sucrose (a w 0.54) and wet-inoculated sucrose (a w 0.24) stored at 25°C for 12 and 26 weeks, respectively. Results emphasize the importance of preventing contamination of sucrose intended for use as an ingredient in foods not subjected to a treatment that would be lethal to Salmonella.

  14. Water activity and temperature effects on germination and growth of Eurotium amstelodami, E. chevalieri and E. herbariorum isolates from bakery products.

    Science.gov (United States)

    Abellana, M; Benedí, J; Sanchis, V; Ramos, A J

    1999-09-01

    This study investigated the effect of temperature (5-30 degrees C), water activity (0.775-0.90 aw) and their interactions on the temporal rates of germination and mycelial growth of three species of Eurotium on flour wheat sucrose medium. Germination was quite rapid at aw >0.85, with an almost linear increase with time for all isolates. However, under more extreme water stress, germination was slower. The aw minima for germination were usually lower than those for growth and varied with temperature. The effect of aw x temperature interactions on the lag phases (h) prior to germination and on the germination rates (h-1) were predicted using the Gompertz model modified by Zwietering. Eurotium spp. had shown short lag times at 0.90 aw over a wide range of temperatures. At marginal temperatures, lag phases were significantly longer, especially at >15 degrees C. The temperature x aw profiles for mycelial growth varied between species in terms of rates (mm d(-1)). Predictions of the effect of important environmental factors, such as temperature, aw and their interactions on lag times to germination, germination rates and mycelial growth, are important in the development of hurdle technology approaches to predict fungal spoilage in food products.

  15. Predictive modelling of the combined effect of temperature and water activity on the in vitro growth of Erwinia spp. infecting potato tubers in Belgium

    Directory of Open Access Journals (Sweden)

    Moh, AA.

    2011-01-01

    Full Text Available Erwinia carotovora ssp. atroseptica (Eca, Erwinia carotovora ssp. carotovora (Ecc and Erwinia chrysanthemi (Ech, are the main cause of potato tuber decay (soft rot in storage and stem rot in the field (blackleg. The bacteria are characterized by the production of several extracellular pectic enzymes among them Pectate Lyase (PEL activity is the most important key of pathogenesis. It has been reported that ecological parameters such as humidity and temperature, greatly influence the disease development. The objective of this work was to determine the in vitro effect of water activity (0.960, 0.980, 0.997 and temperature (10, 15 and 20°C and their interactions on the growth parameters of Eca, Ecc and Ech using optical density (OD measurement. The maximum specific growth rate (µmax was calculated under each aw-temperature combinations for the three Erwinia species. Statistical analysis showed a significant effect of aw and temperature on µmax. We noticed that Eca and Ecc grow faster than Ech in our condition. A second aim of this work was to monitor the PEL specific activity under the combined effect of these two factors (aw-temperature. Our results showed an increase of PEL specific activity with the temperature whatever are the bacterial strains. But contrary to growth, this research did not show an increase of PEL specific activity with aw except the treatment at 15 and 20°C for all bacteria strains. According to our obtained results on growth and PEL production we concluded that Eca 03034/1 and Ecc 030033 had the same ecological behavior comparatively to Ech 03/016/1 in the range of the values of the two factors (aw and temperature investigated here. To our knowledge, this research is the first publication which pointed out the combined in vitro effect of aw and temperature on the growth of Erwinia genius according to literature data.

  16. Effects of biological activity, light, temperature and oxygen on phosphorus release processes at the sediment and water interface of Taihu Lake, China.

    Science.gov (United States)

    Jiang, Xia; Jin, Xiangcan; Yao, Yang; Li, Lihe; Wu, Fengchang

    2008-04-01

    Effects of biological activity, light, temperature and oxygen on the phosphorus (P) release processes at the sediment and water interface of a shallow lake, Taihu Lake, China, were investigated. The results show that organisms at the sediment and water interface can stimulate P release from sediments, and their metabolism can alter the surrounding micro-environmental conditions. The extent of P release and its effects on P concentration in the overlying water were affected by factors such as light, temperature and dissolved oxygen. The organism biomass increased as temperature increased, which was beneficial for P release. Dissolved total phosphorus (DTP) and dissolved inorganic phosphorus (DIP) concentrations in the corresponding overlying water were mainly controlled by light. P release occurred in both aerobic and anoxic conditions with the presence of organisms. However in the presence of light , P release in an anoxic environment was much greater than in an aerobic environment, which may stimulate alga bloom and result in an increase in total phosphorus (TP) in the overlying water. This information aids the understanding of P biogeochemical cycling at the interface and its relationship with eutrophication in shallow lakes.

  17. Effects of temperature, water activity and incubation time on fungal growth and aflatoxin B1 production by toxinogenic Aspergillus flavus isolates on sorghum seeds.

    Science.gov (United States)

    Lahouar, Amani; Marin, Sonia; Crespo-Sempere, Ana; Saïd, Salem; Sanchis, Vicente

    2016-01-01

    Sorghum, which is consumed in Tunisia as human food, suffers from severe colonization by several toxigenic fungi and contamination by mycotoxins. The Tunisian climate is characterized by high temperature and humidity that stimulates mold proliferation and mycotoxin accumulation in foodstuffs. This study investigated the effects of temperature (15, 25 and 37°C), water activity (aw, between 0.85 and 0.99) and incubation time (7, 14, 21 and 28 d) on fungal growth and aflatoxin B1 (AFB1) production by three Aspergillus flavus isolates (8, 10 and 14) inoculated on sorghum grains. The Baranyi model was applied to identify the limits of growth and mycotoxin production. Maximum diameter growth rates were observed at 0.99 a(w) at 37°C for two of the isolates. The minimum aw needed for mycelial growth was 0.91 at 25 and 37°C. At 15°C, only isolate 8 grew at 0.99 a(w). Aflatoxin B1 accumulation could be avoided by storing sorghum at low water activity levels (≤0.91 a(w)). Aflatoxin production was not observed at 15°C. This is the first work on the effects of water activity and temperature on A. flavus growth and AFB1 production by A. flavus isolates on sorghum grains. Copyright © 2015 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Physisorbed Water on Silica at Mars Temperatures

    Science.gov (United States)

    Sutter, B.; Sriwatanapongse, W.; Quinn, R.; Klug, C.; Zent, A.

    2002-01-01

    The usefulness of nuclear magnetic resonance spectroscopy in probing water interactions on silica at Mars temperatures is discussed. Results indicate that two types of water occur with silica at Mars temperatures. Additional information is contained in the original extended abstract.

  19. Drinking Water Temperature Modelling in Domestic Systems

    OpenAIRE

    Moerman, A.; Blokker, M.; Vreeburg, J.; van der Hoek, J.P.

    2014-01-01

    Domestic water supply systems are the final stage of the transport process to deliver potable water to the customers’ tap. Under the influence of temperature, residence time and pipe materials the drinking water quality can change while the water passes the domestic drinking water system. According to the Dutch Drinking Water Act the drinking water temperature may not exceed the 25 °C threshold at point-of-use level. This paper provides a mathematical approach to model the heating of drinking...

  20. Effects of temperature and time on polyphenolic content and antioxidant activity in the pressurized hot water extraction of deodorized thyme (Thymus vulgaris).

    Science.gov (United States)

    Vergara-Salinas, José R; Pérez-Jiménez, Jara; Torres, Josep Lluís; Agosin, Eduardo; Pérez-Correa, José R

    2012-11-07

    The effects of temperature (50-200 °C) and contact time (5-30 min) on the pressurized hot water extraction of deodorized thyme were explored for antioxidant activity, polyphenol profiles, and total antioxidants. Six not previously reported polyphenolic compounds were identified in thyme. An inverse correlation was found between the antioxidant activity and total antioxidants with the amount and diversity of polyphenols. The highest total extract yield and antioxidant activity were obtained at 200 °C, although maximum polyphenol extraction yields of hydroxycinnamic acids, flavones, flavonols/flavanones, and total polyphenols were detected at 100 °C and 5 min. Higher temperatures and longer exposure times reduced extract polyphenol diversity. Dihydroxyphenyllactic acid was the only phenolic compound for which extraction yield increased with temperature, probably as a product of the thermal degradation of rosmarinic acid. Consequently, for extracting phenolics from thyme, 100 °C and 5 min would be appropriate operating conditions, whereas antioxidant-active nonphenolic compounds were favored at higher temperatures and exposure times.

  1. Neuro-fuzzy modeling to predict physicochemical and microbiological parameters of partially dried cherry tomato during storage: effects on water activity, temperature and storage time.

    Science.gov (United States)

    Tao, Yang; Li, Yong; Zhou, Ruiyun; Chu, Dinh-Toi; Su, Lijuan; Han, Yongbin; Zhou, Jianzhong

    2016-10-01

    In the study, osmotically dehydrated cherry tomatoes were partially dried to water activity between 0.746 and 0.868, vacuum-packed and stored at 4-30 °C for 60 days. Adaptive neuro-fuzzy inference system (ANFIS) was utilized to predict the physicochemical and microbiological parameters of these partially dried cherry tomatoes during storage. Satisfactory accuracies were obtained when ANFIS was used to predict the lycopene and total phenolic contents, color and microbial contamination. The coefficients of determination for all the ANFIS models were higher than 0.86 and showed better performance for prediction compared with models developed by response surface methodology. Through ANFIS modeling, the effects of storage conditions on the properties of partially dried cherry tomatoes were visualized. Generally, contents of lycopene and total phenolics decreased with the increase in water activity, temperature and storage time, while aerobic plate count and number of yeasts and molds increased at high water activities and temperatures. Overall, ANFIS approach can be used as an effective tool to study the quality decrease and microbial pollution of partially dried cherry tomatoes during storage, as well as identify the suitable preservation conditions.

  2. Micro-scale heterogeneity in water temperature | Dallas | Water SA

    African Journals Online (AJOL)

    Micro-scale heterogeneity in water temperature was examined in 6 upland sites in the Western Cape, South Africa. Hourly water temperature data converted to daily data showed that greatest differences were apparent in daily maximum temperatures between shallow- and deep-water biotopes during the warmest period of ...

  3. High concentration powdered activated carbon-membrane bioreactor (PAC-MBR) for slightly polluted surface water treatment at low temperature.

    Science.gov (United States)

    Ma, Cong; Yu, Shuili; Shi, Wenxin; Tian, Wende; Heijman, S G J; Rietveld, L C

    2012-06-01

    In this study, different concentrations of PAC combined with MBR were carried out to treat slightly polluted surface water (SPSW) at low temperature (10°C). Effects of PAC on the efficiencies of operation, treatment, and the performance of the process were investigated. It was found that the effluent quality, performance efficiency, resistance of shock load were all enhanced and chemical irreversible membrane fouling was reduced with increasing dosage of PAC in MBR. Only when the concentration of PAC which acted as biological carriers was high enough (i.g., 50 g/L), nitrification without initial inoculation in the filtration tank could start within 19 days and be completed within 35 days at 10°C. Fifty grams per liter PAC was the optimal dosage in MBR for stable and extended operation. Under this condition, mean removal efficiencies of ammonia nitrogen (NH(3)-N), dissolved organic carbon (DOC) and UV(254) were 93%, 75%, and 85%, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Intermediate Temperature Water Heat Pipe Tests

    Science.gov (United States)

    Devarakonda, Angirasa; Xiong, Da-Xi; Beach, Duane E.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range. Fabrication and testing issues are being addressed.

  5. The effect of microwave-frequency discharge-activated oxygen on the microscale structure of low-temperature water ice films

    Science.gov (United States)

    Doering, Skye R.; Strobush, Kirsten M.; Marschall, Jochen; Boulter, James E.

    2009-12-01

    Low-temperature, amorphous water ice films grown by vapor deposition under high-vacuum are exposed to microwave-frequency discharge-activated oxygen in order to investigate its effect on the ice surface. Adsorption of methane is used to probe alterations to microscale structures and surface morphology. Films are interrogated throughout the experiment by grazing-angle Fourier-transform infrared reflection-absorption spectroscopy, and after the experiment by temperature-programmed desorption mass spectrometry. Multilayer Fresnel thin-film optics simulations aid in the interpretation of absorbance spectra. Using these techniques, structural alterations are observed over a range of spatial and time scales. At first, spectral absorbance features arising from incompletely coordinated water molecules disappear. The density of high-energy methane adsorption sites is reduced, lowering the equilibrium amount of adsorbed methane. At longer exposure times, this is manifested in a narrowing of the width of the primary methane desorption peak, indicating a narrower range of methane adsorption energies on the ice surface. Together these observations indicate restructuring of micropores resulting in an increase in the structural homogeneity of the film. Enhancement of small, higher-temperature methane desorption features associated with methane encapsulation during thermal annealing indicates alterations to larger pore structures by the same restructuring process. Attribution of these effects to various energetic species in active oxygen is discussed. Based on their abundance, O(P3) and O2(aΔ1g) are the most likely candidates; other trace atomic and molecular species may also contribute.

  6. Drinking Water Temperature Modelling in Domestic Systems

    NARCIS (Netherlands)

    Moerman, A.; Blokker, M.; Vreeburg, J.; Van der Hoek, J.P.

    2014-01-01

    Domestic water supply systems are the final stage of the transport process to deliver potable water to the customers’ tap. Under the influence of temperature, residence time and pipe materials the drinking water quality can change while the water passes the domestic drinking water system. According

  7. Enzyme stability of microencapsulated Bifidobacterium animalis ssp. lactis Bb12 after freeze drying and during storage in low water activity at room temperature.

    Science.gov (United States)

    Dianawati, Dianawati; Shah, Nagendra P

    2011-08-01

    Stability of enzymes such as β-galactosidase (β-gal), β-glucosidase (β-glu), lactate dehydrogenase (LDH), pyruvate kinase (PK), hexokinase (HK), and ATPase of microencapsulated Bifidobacterium animalis ssp. lactis Bb12 after freeze-drying and after 10 wk of storage at low water activity (a(w)) at room temperature was studied. Bacteria were microencapsulated using alginate formulation with or without mannitol fortification (sodium alginate and mannitol [SAM] and sodium alginate [SA], respectively) by creating gel beads followed by freeze drying. Two types of dried gel beads were then stored at low a(w), such as 0.07, 0.1, and 0.2; storage in an aluminum foil was used as control. All storage was carried out at room temperature of 25 °C for 10 wk. Measurement of β-gal, β-glu, LDH, PK, HK, and ATPase (with or without exposure to pH 2.0 for 2 h) activities was carried out before freeze drying, after freeze drying, and after 10 wk of storage. There was a significant decrease in almost all enzyme activities, except that of PK. SAM and SA showed no different effect on maintaining enzyme activities during freeze drying. Storage for 10 wk at room temperature at various low a(w) using SAM and SA system had a significant effect on retention of most enzymes studied, except that of PK and LDH. Storage at a(w) of 0.07 and 0.1 was more effective in maintaining enzyme activities than storage at a(w) of 0.2 and in an aluminum foil. However, mannitol fortification into alginate system did not significantly improve retention of enzymes during 10 wk of storage. © 2011 Institute of Food Technologists®

  8. Seasonal migration, vertical activity and winter temperature experience of Greenland halibut Reinhardtius hippoglossoides (Walbaum) in West Greenland waters

    DEFF Research Database (Denmark)

    Boje, Jesper; Neuenfeldt, Stefan; Sparrevohn, Claus Reedtz

    2014-01-01

    resident in Disko Bay (mean range 2.6°C) than when resident in the ice fjord (mean range 1.4°C). Using the tagged halibut as a 'live tool,' we show that parts of the ice fjord are hundreds of meters deeper than previously thought. We also document the first seawater temperature measurements made beneath...

  9. Impact of different water activities (aw adjusted by solutes on high pressure high temperature inactivation of Bacillus amyloliquefaciens spores

    Directory of Open Access Journals (Sweden)

    Robert eSevenich

    2015-07-01

    Full Text Available Much research has been conducted to comprehend the mechanisms of high pressure (HP inactivation of spores in aqueous systems but for food model systems these information are scarce. In these systems spores can interact with ingredients which could lead to retarded inactivation, which can cause a problem for the sterilization process. The protective mechanism of a reduced a_W-value is still unclear. HP processing might prove valuable to overcome protective effects of solutes and achieve shorter process times for sterilization under HP. To gain insight into the underlying mechanisms five a_W-values (0.9, 0.92, 0.94, 0.96, 1 were adjusted with 2 different solutes (NaCl, sucrose. Solutions were inoculated with spores of Bacillus amyloliquefaciens and treated at 105,110°C and115°C at 600 MPa. A thermal inactivation was conducted at the same temperatures for a compraison with the high pressure data. The influence of high pressure high temperature treatment on the inactivation, the DPA-release and membrane constitution was assessed by plate count, HPLC and flow cytometry. The results show that during HP treatments sucrose and salt both have a protective effect, in which the influence of sucrose on the retarded inactivation is higher. The threshold aw, which is 0.94, here salt and sucrose have a significant influence on the inactivation. The comparison of thermal (105-115°C and high pressure and high temperature (600 MPa, 105-115°C treated samples showed that the time needed to achieve a 4-5 log inactivation can be reduced at 600 MPa.The release of dipicolinic acid (DPA is the rate limiting step of the inactivation and therefore monitoring the release is of great interest. The DPA-release is slowed is slowed down in high concentrated solutions (e.g. sucrose, salt in comparison to aw 1. Maybe as shown for vegetative microorganism the solutes can interact with membranes, e.g. inner spore membrane. FCM (flow cytometry measurement data show a similar

  10. Effect of temperature, water activity, and pH on growth and production of ochratoxin A by Aspergillus niger and Aspergillus carbonarius from Brazilian grapes.

    Science.gov (United States)

    Passamani, Fabiana Reinis Franca; Hernandes, Thais; Lopes, Noelly Alves; Bastos, Sabrina Carvalho; Santiago, Wilder Douglas; Cardoso, Maria das Graças; Batista, Luís Roberto

    2014-11-01

    The growth of ochratoxigenic fungus and the presence of ochratoxin A (OTA) in grapes and their derivatives can be caused by a wide range of physical, chemical, and biological factors. The determination of interactions between these factors and fungal species from different climatic regions is important in designing models for minimizing the risk of OTA in wine and grape juice. This study evaluated the influence of temperature, water activity (aw), and pH on the development and production of OTA in a semisynthetic grape culture medium by Aspergillus carbonarius and Aspergillus niger strains. To analyze the growth conditions and production of OTA, an experimental design was conducted using response surface methodology as a tool to assess the effects of these abiotic variables on fungal behavior. A. carbonarius showed the highest growth at temperatures from 20 to 33°C, aw between 0.95 and 0.98, and pH levels between 5 and 6.5. Similarly, for A. niger, temperatures between 24 and 37°C, aw greater than 0.95, and pH levels between 4 and 6.5 were optimal. The greatest toxin concentrations for A. carbonarius and A. niger (10 μg/g and 7.0 μg/g, respectively) were found at 15°C, aw 0.99, and pH 5.35. The lowest pH was found to contribute to greater OTA production. These results show that the evaluated fungi are able to grow and produce OTA in a wide range of temperature, aw, and pH. However, the optimal conditions for toxin production are generally different from those optimal for fungal growth. The knowledge of optimal conditions for fungal growth and production of OTA, and of the stages of cultivation in which these conditions are optimal, allows a more precise assessment of the potential risk to health from consumption of products derived from grapes.

  11. NOAA NOS SOS, EXPERIMENTAL - Water Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have water temperature data. *These services are for testing and evaluation...

  12. Water activity in polyol/water systems: new UNIFAC parameterization

    OpenAIRE

    Marcolli, C.; Peter, Th.

    2005-01-01

    Water activities of a series of polyol/water systems were measured with an AquaLab dew point water activity meter at 298 K. The investigated polyols with carbon numbers from n=2–7 are all in liquid state at room temperature and miscible at any molar ratio 5 with water. In aqueous solutions with the same mass concentration, the diols with lower molecular weight lead to lower water activities than those with higher molecular weights. For diols with four or more carbon atoms, the hygro...

  13. The Effect of Contrast Temperature Water Therapy on Blood Lactic Acid clearance of male students of Mazandaran University of Science and Technology after exhausting activity

    Directory of Open Access Journals (Sweden)

    Mohammadbagher Forghani

    2015-09-01

    Full Text Available The purpose of this research was the considering of the effect of Contrast Temperature Water Therapy on Blood Lactic Acid clearance of male students of Mazandaran University of Science and Technology after exhausting activity. In this semi-experimental study, 30 male students were randomly chosen and classified between two groups with 15 members, in a design with control group and experimental group, before and two hours after CTWT (experimental group the Bruce test on treadmill was done. The measurement of blood Lactic Acid was done by Lactometer, before and after Bruce tests, and also immediately after CTWT. And then in both groups the results of each test was compared with another test. After that the results between two groups were compared. To analyze the data, the Kolmogorov-Smirnov test, pair T test, and match T test were used in meaning level α≤0/05 for statistical analyze. To summarize, the following findings have been obtained: 1.CTWT reduced the concentration of blood Lactic Acid after exhausting performance significantly; 2. Two hours after recovery, the effect of CTWT on Lactic Acid concentration did not differ from the passive recovery method effect significantly; 3. CTWT did not also have any significant effect on the Lactic Acid accumulation in next exhausting performance; 4. CTWT did not have any significant effect on fluctuations of blood Lactic Acid in next exhausting performance. It is believed that CTWT facilitates recovery by blood circulation, vaso-pumping, hydrostatic pressure due to immersion, relieving of metabolic waste, and central nervous system stimulation. Keywords: Contrast Temperature Water Therapy, exhausting performance, Lactic Acid clearance

  14. Quantifying the effect of water activity and storage temperature on single spore lag times of three moulds isolated from spoiled bakery products.

    Science.gov (United States)

    Dagnas, Stéphane; Gougouli, Maria; Onno, Bernard; Koutsoumanis, Konstantinos P; Membré, Jeanne-Marie

    2017-01-02

    The inhibitory effect of water activity (aw) and storage temperature on single spore lag times of Aspergillus niger, Eurotium repens (Aspergillus pseudoglaucus) and Penicillium corylophilum strains isolated from spoiled bakery products, was quantified. A full factorial design was set up for each strain. Data were collected at levels of aw varying from 0.80 to 0.98 and temperature from 15 to 35°C. Experiments were performed on malt agar, at pH5.5. When growth was observed, ca 20 individual growth kinetics per condition were recorded up to 35days. Radius of the colony vs time was then fitted with the Buchanan primary model. For each experimental condition, a lag time variability was observed, it was characterized by its mean, standard deviation (sd) and 5th percentile, after a Normal distribution fit. As the environmental conditions became stressful (e.g. storage temperature and aw lower), mean and sd of single spore lag time distribution increased, indicating longer lag times and higher variability. The relationship between mean and sd followed a monotonous but not linear pattern, identical whatever the species. Next, secondary models were deployed to estimate the cardinal values (minimal, optimal and maximal temperatures, minimal water activity where no growth is observed anymore) for the three species. That enabled to confirm the observation made based on raw data analysis: concerning the temperature effect, A. niger behaviour was significantly different from E. repens and P. corylophilum: Topt of 37.4°C (standard deviation 1.4°C) instead of 27.1°C (1.4°C) and 25.2°C (1.2°C), respectively. Concerning the aw effect, from the three mould species, E. repens was the species able to grow at the lowest aw (awmin estimated to 0.74 (0.02)). Finally, results obtained with single spores were compared to findings from a previous study carried out at the population level (Dagnas et al., 2014). For short lag times (≤5days), there was no difference between lag time of

  15. Modeling growth rate and assessing aflatoxins production by Aspergillus flavus as a function of water activity and temperature on polished and brown rice.

    Science.gov (United States)

    Mousa, Wael; Ghazali, Farinazleen Mohd; Jinap, Selamat; Ghazali, Hasanah Mohd; Radu, Son

    2013-01-01

    The aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (a(w) 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily, and the aflatoxins were analyzed using HPLC with a fluorescence detector. The growth rates were estimated using the primary model of Baranyi, which describes the change in colony radius as a function of time. Total of 2 secondary models were used to describe the combined effects of a(w) and temperature on the growth rates. The models were validated using independent experimental data. Linear Arrhenius-Davey model proved to be the best predictor of A. flavus growth rates on polished and brown rice followed by polynomial model. The estimated optimal growth temperature was around 30 °C. A. flavus growth and aflatoxins were not detected at 0.82 a(w) on polished rice while growth and aflatoxins were detected at this a(w) between 25 and 35 °C on brown rice. The highest amounts of toxins were formed at the highest a(w) values (0.90 to 0.92) at a temperature of 20 °C after 21 d of incubation on both types of rice. Nevertheless, the consistencies of toxin production within a wider range of a(w) values occurred between 25 to 30 °C. Brown rice seems to support A. flavus growth and aflatoxin production more than the polished rice. The developed models can be used to estimate to what extent the change in grain ecosystem conditions affect the storage stability and safety of grains without the need for running long-standing storage study. By monitoring the intergranular relative humidity and temperature at different locations in the storage facility and inputting these data into the models, it is directly possible to assess either the conditions are conductive for the growth of A. flavus or aflatoxin production. © 2012 Institute of Food Technologists®

  16. Soil Water and Temperature System (SWATS) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Bond, D

    2005-01-01

    The soil water and temperature system (SWATS) provides vertical profiles of soil temperature, soil-water potential, and soil moisture as a function of depth below the ground surface at hourly intervals. The temperature profiles are measured directly by in situ sensors at the Central Facility and many of the extended facilities of the SGP climate research site. The soil-water potential and soil moisture profiles are derived from measurements of soil temperature rise in response to small inputs of heat. Atmospheric scientists use the data in climate models to determine boundary conditions and to estimate the surface energy flux. The data are also useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil.

  17. Development of a predictive model for Salmonella spp. reduction in meat jerky product with temperature, potassium sorbate, pH, and water activity as controlling factors.

    Science.gov (United States)

    Juneja, Vijay K; Valenzuela-Melendres, Martin; Heperkan, Dilek; Bautista, Derrick; Anderson, David; Hwang, Cheng-An; Peña-Ramos, Aida; Camou, Juan Pedro; Torrentera-Olivera, Noemi

    2016-11-07

    The objective of this study was to develop a predictive model for the inactivation of Salmonella spp. in ground beef jerky as a function of temperature (T), pH, potassium sorbate (PS), and final water activity (aw). Following a central composite design, ground beef was combined with PS (0 to 0.3%, w/w), pH adjusted from 5 to 7, inoculated with a cocktail of 6 serotypes of Salmonella spp. and heat processed at temperatures between 65 and 85°C until the final aw ranging from 0.65 to 0.85 was achieved. Surviving Salmonella cells were enumerated on tryptic soy agar overlaid with xylose lysine deoxycholate agar (pre-tempered to 47°C) after incubation for 48h at 30°C. Bacterial inactivation was quantified in terms of logarithmic reductions of Salmonella counts (log10CFU/g) and inactivation rate (log10(CFU/g)/h). The results indicated that pH, PS and T significantly (pbeef jerky. Decreasing meat pH significantly (pBeef jerky processed at 82°C, pH5.5, with 0.25% PS to a final aw of 0.7 resulted in a maximum Salmonella logarithmic reduction of 5.0log10CFU/g and an inactivation rate of 1.3log10(CFU/g)/h. The predictive model developed can be used to effectively design drying processes for beef jerky under low humidity conditions and thereby, ensuring an adequate degree of protection against risks associated with Salmonella spp. Copyright © 2016. Published by Elsevier B.V.

  18. Dynamic water vapor and temperature calibration system.

    Science.gov (United States)

    Montague, F W; Primiano, F P; Saidel, G M

    1984-06-01

    The objective evaluation of thermal and humidification processes in the pulmonary system requires accurate dynamic measurements of temperature and water vapor concentration of a flowing gas mixture. The adequacy of instruments used for such measurements can only be determined by dynamic calibration techniques. We have developed a method of producing step changes in temperature and water vapor content of a gas mixture undergoing controlled steady flow. The system consists of two reservoirs and a slide valve that switches a test section between them. The inlet (usually a probe or catheter tip) of the device to be calibrated is positioned in the test section. The flow rate through the test section is minimally changed during the transition between gas from one reservoir to that of the other. The system has been used to analyze the response of a thermistor and a respiratory mass spectrometer to changes in gas temperature and water vapor.

  19. Prokaryotic community structure and activity of sulfate reducers in production water from high-temperature oil reservoirs with and without nitrate treatment

    DEFF Research Database (Denmark)

    Gittel, Antje; Sørensen, Ketil; Skovhus, Torben L.

    2009-01-01

    Sulfate-reducing prokaryotes (SRP) cause severe problems like microbial corrosion and reservoir souring in seawater-injected oil production systems. One strategy to control SRP activity is the addition of nitrate to the injection water. Production waters from two adjacent, hot (80°C) oil reservoirs...

  20. Modelling the effect of temperature, water activity and carbon dioxide on the growth of Aspergillus niger and Alternaria alternata isolated from fresh date fruit.

    Science.gov (United States)

    Belbahi, A; Leguerinel, I; Méot, J-M; Loiseau, G; Madani, K; Bohuon, P

    2016-12-01

    To quantify and model the combined effects of temperature (T) (10-40°C), water activity (aw ) (0·993-0·818) and CO2 concentration (9·4-55·1%, v/v) on the growth rate of Aspergillus niger and Alternaria alternata that cause spoilage during the storage and packaging of dates. The effects of environmental factors were studied using the γ-concept. Cardinal models were used to quantify the effect of studied environmental factors on the growth rates. Firstly, the cardinal parameters were estimated independently from experiments carried out on potato dextrose agar using a monofactorial design. Secondly, model performance evaluation was conducted on pasteurized date paste. The boundary between growth and no-growth was predicted using a deterministic approach. Aspergillus niger displayed a faster growth rate and higher tolerance to low aw than Al. alternata, which in turn proved more resistant to CO2 concentration. Minimal cardinal parameters of T and aw were lower than those reported in the literature. The combination of the aw and CO2 effects significantly affected As. niger and Al. alternata growth. The γ-concept model overestimated growth rates, however, it is optimistic and provides somewhat conservative predictions. The developed model provides a decision support tool for the choice of the date fruit conservation mode (refrigeration, drying, modified atmospheric packaging or their combination) using T, aw and CO2 as environmental factors. © 2016 The Society for Applied Microbiology.

  1. Water activity in polyol/water systems: new UNIFAC parameterization

    Science.gov (United States)

    Marcolli, C.; Peter, Th.

    2005-06-01

    Water activities of a series of polyol/water systems were measured with an AquaLab dew point water activity meter at 298K. The investigated polyols with carbon numbers from n=2-7 are all in liquid state at room temperature and miscible at any molar ratio with water. In aqueous solutions with the same molar concentration, the diols with lower molecular weight lead to lower water activities than those with higher molecular weights. For diols with four or more carbon atoms, the hydrophilicity shows considerable differences between isomers: The 1,2-isomers - consisting of a hydrophilic and a hydrophobic part - bind less strongly to water than isomers with a more balanced distribution of the hydroxyl groups. The experimental water activities were compared with the predictions of the group contribution method UNIFAC: the model predictions overestimate the water activity of water/polyol systems of substances with two or more hydroxyl groups and can not describe the decreased binding to water of isomers with hydrophobic tails. To account for the differences between isomers, a modified UNIFAC parameterization was developed, that allows to discriminate between three types of alkyl groups depending on their position in the molecule. These new group interaction parameters were calculated using water activities of alcohol/water mixtures. This leads to a distinctly improved agreement of model predictions with experimental results while largely keeping the simplicity of the functional group approach.

  2. Water activity in polyol/water systems: new UNIFAC parameterization

    Directory of Open Access Journals (Sweden)

    C. Marcolli

    2005-01-01

    Full Text Available Water activities of a series of polyol/water systems were measured with an AquaLab dew point water activity meter at 298K. The investigated polyols with carbon numbers from n=2-7 are all in liquid state at room temperature and miscible at any molar ratio with water. In aqueous solutions with the same molar concentration, the diols with lower molecular weight lead to lower water activities than those with higher molecular weights. For diols with four or more carbon atoms, the hydrophilicity shows considerable differences between isomers: The 1,2-isomers - consisting of a hydrophilic and a hydrophobic part - bind less strongly to water than isomers with a more balanced distribution of the hydroxyl groups. The experimental water activities were compared with the predictions of the group contribution method UNIFAC: the model predictions overestimate the water activity of water/polyol systems of substances with two or more hydroxyl groups and can not describe the decreased binding to water of isomers with hydrophobic tails. To account for the differences between isomers, a modified UNIFAC parameterization was developed, that allows to discriminate between three types of alkyl groups depending on their position in the molecule. These new group interaction parameters were calculated using water activities of alcohol/water mixtures. This leads to a distinctly improved agreement of model predictions with experimental results while largely keeping the simplicity of the functional group approach.

  3. Escherichia coli survival in waters: Temperature dependence

    Science.gov (United States)

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q10 mo...

  4. Active thermal isolation for temperature responsive sensors

    Science.gov (United States)

    Martinson, Scott D. (Inventor); Gray, David L. (Inventor); Carraway, Debra L. (Inventor); Reda, Daniel C. (Inventor)

    1994-01-01

    A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specified surface of the body. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes: (1) operating the isolator at the same temperature as the constant temperature of the sensor and (2) establishing a fixed boundary temperature which is either less than or equal to or slightly greater than the sensor constant temperature.

  5. Escherichia coli survival in waters: temperature dependence.

    Science.gov (United States)

    Blaustein, R A; Pachepsky, Y; Hill, R L; Shelton, D R; Whelan, G

    2013-02-01

    Knowing the survival rates of water-borne Escherichia coli is important in evaluating microbial contamination and making appropriate management decisions. E. coli survival rates are dependent on temperature, a dependency that is routinely expressed using an analogue of the Q₁₀ model. This suggestion was made 34 years ago based on 20 survival curves taken from published literature, but has not been revisited since then. The objective of this study was to re-evaluate the accuracy of the Q₁₀ equation, utilizing data accumulated since 1978. We assembled a database of 450 E. coli survival datasets from 70 peer-reviewed papers. We then focused on the 170 curves taken from experiments that were performed in the laboratory under dark conditions to exclude the effects of sunlight and other field factors that could cause additional variability in results. All datasets were tabulated dependencies "log concentration vs. time." There were three major patterns of inactivation: about half of the datasets had a section of fast log-linear inactivation followed by a section of slow log-linear inactivation; about a quarter of the datasets had a lag period followed by log-linear inactivation; and the remaining quarter were approximately linear throughout. First-order inactivation rate constants were calculated from the linear sections of all survival curves and the data grouped by water sources, including waters of agricultural origin, pristine water sources, groundwater and wells, lakes and reservoirs, rivers and streams, estuaries and seawater, and wastewater. Dependency of E. coli inactivation rates on temperature varied among the water sources. There was a significant difference in inactivation rate values at the reference temperature between rivers and agricultural waters, wastewaters and agricultural waters, rivers and lakes, and wastewater and lakes. At specific sites, the Q₁₀ equation was more accurate in rivers and coastal waters than in lakes making the value of

  6. Modelling highly variable daily maximum water temperatures in a ...

    African Journals Online (AJOL)

    ... hourly water temperatures were used to calculate daily maximum water temperatures for nine sites within the Sabie-Sand River system, Mpumalanga Province, South Africa. A suite of statistical models for simulating daily maximum water temperatures, of differing complexity and using inputs of air temperature, flow rates, ...

  7. 21 CFR 880.5560 - Temperature regulated water mattress.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Temperature regulated water mattress. 880.5560... Therapeutic Devices § 880.5560 Temperature regulated water mattress. (a) Identification. A temperature... heating and water circulating components, and an optional cooling component. The temperature control may...

  8. The effect of cool water ingestion on gastrointestinal pill temperature.

    Science.gov (United States)

    Wilkinson, David M; Carter, James M; Richmond, Victoria L; Blacker, Sam D; Rayson, Mark P

    2008-03-01

    Telemetric gastrointestinal (GI) temperature pills are now commonly used to measure core body temperature and could minimize the risk of heat illness while maximizing operational effectiveness in workers subject to high levels of thermal strain. To quantify the effect of repeated cool water ingestion on the accuracy of GI pill temperature. Ten operational firefighters ingested a pill to measure GI temperature (T1int) before overnight sleep. Two hours following breakfast and 11.5 h after ingesting T1int, the firefighters ingested a second pill (T2int) before performing 8.5 h of intermittent activity (repetitive cycles of 30 min of seated rest followed by 30 min of general firefighter duties). During the first 2 min of each 30-min rest period, the firefighters consumed 250 mL of chilled water (5-8 degrees C). Water ingestion had a highly variable effect both within and between subjects in transiently (32 +/- 10 min) reducing the temperature of T2int in comparison with T1int. In general, this transient reduction in T2int became progressively smaller as time following ingestion increased. In some firefighters, the difference between T1int and T2int became negligible (+/- 0.1 degrees C) after 3 h, whereas in two others, large differences (peaking at 2.0 degrees C and 6.3 degrees C) were still observed when water was consumed 8 h after pill ingestion. These results show that a GI pill ingested immediately prior to physical activity cannot be used to measure core body temperature accurately in all individuals during the following 8 h when cool fluids are regularly ingested. This makes GI temperature measurement unsuitable for workers who respond to emergency deployments when regular fluid consumption is recommended operational practice.

  9. Trihalomethane hydrolysis in drinking water at elevated temperatures.

    Science.gov (United States)

    Zhang, Xiao-Lu; Yang, Hong-Wei; Wang, Xiao-Mao; Karanfil, Tanju; Xie, Yuefeng F

    2015-07-01

    Hydrolysis could contribute to the loss of trihalomethanes (THMs) in the drinking water at elevated temperatures. This study was aimed at investigating THM hydrolysis pertaining to the storage of hot boiled water in enclosed containers. The water pH value was in the range of 6.1-8.2 and the water temperature was varied from 65 to 95 °C. The effects of halide ions, natural organic matter, and drinking water matrix were investigated. Results showed that the hydrolysis rates declined in the order following CHBrCl2 > CHBr2Cl > CHBr3 > CHCl3. THM hydrolysis was primarily through the alkaline pathway, except for CHCl3 in water at relatively low pH value. The activation energies for the alkaline hydrolysis of CHCl3, CHBrCl2, CHBr2Cl and CHBr3 were 109, 113, 115 and 116 kJ/mol, respectively. No hydrolysis intermediates could accumulate in the water. The natural organic matter, and probably other constituents, in drinking water could substantially decrease THM hydrolysis rates by more than 50%. When a drinking water was at 90 °C or above, the first order rate constants for THM hydrolysis were in the magnitude of 10(-2)‒10(-1) 1/h. When the boiled real tap water was stored in an enclosed container, THMs continued increasing during the first few hours and then kept decreasing later on due to the competition between hydrolysis and further formation. The removal of THMs, especially brominated THMs, by hydrolysis would greatly reduce one's exposure to disinfection by-products by consuming the boiled water stored in enclosed containers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Active CdS/rGO photocatalyst by a high temperature gas-solid reaction for hydrogen production by splitting of water

    Science.gov (United States)

    Singh, Arvind; Sinha, A. S. K.

    2018-02-01

    rGO supported CdS photocatalysts has been prepared by a two steps method, i.e. impregnation of GO/rGO with CdSO4 followed by a high temperature reaction with H2S gas. Activity of this catalyst was superior to a catalyst of same composition prepared by commonly reported hydrothermal technique. Detailed microstructure studies were carried out using FTIR, PL, DRS, XRD, TEM, SAED, TPO and XPS. A much greater chemical interaction at the interface of CdS and rGO and also a higher absorption of visible light were observed in the reported catalyst. It has been concluded that the high temperature reaction with H2S has imparted n-type semiconductivity to CdS which with p-type rGO and synergy of chemical interaction at the interface has resulted into formation of a p-n hetrojunction. The formation of hetrojunction and high electron mobility of rGO has given a superior activity due to an efficient charge separation to the catalyst prepared by the technique reported in this paper.

  11. Effect of water content and temperature on Carica papaya lipase catalyzed esterification and transesterification reactions

    Directory of Open Access Journals (Sweden)

    Turon Fabrice

    2003-09-01

    Full Text Available Temperature and water activity (a w of the reaction medium are two factors that govern enzyme reactions. We studied the influence of these two parameters on the esterification and transesterification activity of Carica papaya lipase in water and solvent free reactions. It was found that over the course of reaction the catalytic activity of C. papaya lipase was dependent on these factors. The best lipase activity for both reactions was at a temperature of 55°C and water activity of 0.22, which corresponds to 2 g of water per 100 g of C. papaya latex.

  12. Moisture Absorption Model of Composites Considering Water Temperature Effect

    Directory of Open Access Journals (Sweden)

    HUI Li

    2016-11-01

    Full Text Available The influence of water temperature on composite moisture absorption parameters was investigated in temperature-controlled water bath. Experiments of carbon fiber/bismaleimide resin composites immersed in water of 60℃, 70℃and 80℃ were developed respectively. According to the moisture content-time curves obtained from the experimental results, the diffusion coefficient and the balanced moisture content of the composites immersed in different water temperature could be calculated. What's more, the effect of water temperature on the diffusion coefficient and the balanced moisture content were discussed too. According to the Arrhenius equation and the law of Fick, a moisture absorption model was proposed to simulate the hygroscopic behaviour of the composite laminates immersed in different water temperature which can predict the absorption rate of water of the composites immersed in distilled water of 95℃ at any time precisely and can calculate how long it will take to reach the specific absorption rate.

  13. Effects of Temperature and Growing Seasons on Crop Water ...

    African Journals Online (AJOL)

    PROF HORSFALL

    ABSTRACT: Water savings can be improved through reducing agricultural water consumption. The crop water requirement (CWR) depends on several factors including temperature and growing seasons. This study investigated the effects of temperature and growing seasons on CWR in Saudi Arabia. Increase in ...

  14. Air-water partitioning of 222Rn and its dependence on water temperature and salinity.

    Science.gov (United States)

    Schubert, Michael; Paschke, Albrecht; Lieberman, Eric; Burnett, William C

    2012-04-03

    Radon is useful as a tracer of certain geophysical processes in marine and aquatic environments. Recent applications include detection of groundwater discharges into surface waters and assessment of air/sea gas piston velocities. Much of the research performed in the past decade has relied on continuous measurements made in the field using a radon stripping unit connected to a radon-in-air detection system. This approach assumes that chemical equilibrium is attained between the water and gas phases and that the resulting air activity can be multiplied by a partition coefficient to obtain the corresponding radon-in-water activity. We report here the results of a series of laboratory experiments that describes the dependence of the partition coefficient upon both water temperature and salinity. Our results show that the temperature dependence for freshwater closely matches results that were previously available. The salinity effect, however, has largely been ignored and our results show that this can result in an overestimation of radon concentrations, especially in cooler, more saline waters. Related overestimates in typical situations range between 10 (warmer less saline waters) and 20% (cooler, more saline waters).

  15. The analysis of energy efficiency in water electrolysis under high temperature and high pressure

    Science.gov (United States)

    Hourng, L. W.; Tsai, T. T.; Lin, M. Y.

    2017-11-01

    This paper aims to analyze the energy efficiency of water electrolysis under high pressure and high temperature conditions. The effects of temperature and pressure on four different kinds of reaction mechanisms, namely, reversible voltage, activation polarization, ohmic polarization, and concentration polarization, are investigated in details. Results show that the ohmic and concentration over-potentials are increased as temperature is increased, however, the reversible and activation over-potentials are decreased as temperature is increased. Therefore, the net efficiency is enhanced as temperature is increased. The efficiency of water electrolysis at 350°C/100 bars is increased about 17%, compared with that at 80°C/1bar.

  16. The effect of pavement-watering on subsurface pavement temperatures

    OpenAIRE

    Hendel, Martin; Royon, Laurent

    2015-01-01

    International audience; Pavement-watering is currently viewed as a potential climate change adaptation and urban heat island mitigation technique. The effects of pavement-watering on pavement temperature measured 5 cm deep are presented and discussed. Subsurface temperature measurements could not be used to improve or optimize pavement-watering methods as was seen in previous work on surface temperatures or subsurface pavement heat flux measurements.

  17. Active thermal isolation for temperature responsive sensors

    Science.gov (United States)

    Martinson, Scott D. (Inventor); Gray, David L. (Inventor); Carraway, Debra L. (Inventor); Reda, Daniel C. (Inventor)

    1994-01-01

    The detection of flow transition between laminar and turbulent flow and of shear stress or skin friction of airfoils is important in basic research for validation of airfoil theory and design. These values are conventionally measured using hot film nickel sensors deposited on a polyimide substrate. The substrate electrically insulates the sensor and underlying airfoil but is prevented from thermally isolating the sensor by thickness constraints necessary to avoid flow contamination. Proposed heating of the model surface is difficult to control, requires significant energy expenditures, and may alter the basic flow state of the airfoil. A temperature responsive sensor is located in the airflow over the specified surface of a body and is maintained at a constant temperature. An active thermal isolator is located between this temperature responsive sensor and the specific surface of the body. The total thickness of the isolator and sensor avoid any contamination of the flow. The temperature of this isolator is controlled to reduce conductive heat flow from the temperature responsive sensor to the body. This temperature control includes (1) operating the isolator at the same temperature as the constant temperature of the sensor; and (2) establishing a fixed boundary temperature which is either less than or equal to, or slightly greater than the sensor constant temperature. The present invention accordingly thermally isolates a temperature responsive sensor in an energy efficient, controllable manner while avoiding any contamination of the flow.

  18. Thermal infrared remote sensing of water temperature in riverine landscapes

    Science.gov (United States)

    Handcock, Rebecca N.; Torgersen, Christian E.; Cherkauer, Keith A.; Gillespie, Alan R.; Klement, Tockner; Faux, Russell N.; Tan, Jing; Carbonneau, Patrice E.; Piégay, Hervé

    2012-01-01

    Water temperature in riverine landscapes is an important regional indicator of water quality that is influenced by both ground- and surface-water inputs, and indirectly by land use in the surrounding watershed (Brown and Krygier, 1970; Beschta et al., 1987; Chen et al., 1998; Poole and Berman, 2001).Coldwater fishes such as salmon and trout are sensitive to elevated water temperature; therefore, water temperature must meet management guidelines and quality standards, which aim to create a healthy environment for endangered populations (McCullough et al., 2009). For example, in the USA, the Environmental Protection Agency (EPA) has established water quality standards to identify specific temperature criteria to protect coldwater fishes (Environmental Protection Agency, 2003). Trout and salmon can survive in cool-water refugia even when temperatures at other measurement locations are at or above the recommended maximums (Ebersole et al., 2001; Baird and Krueger, 2003; High et al., 2006). Spatially extensive measurements of water temperature are necessary to locate these refugia, to identify the location of ground- and surface-water inputs to the river channel, and to identify thermal pollution sources. Regional assessment of water temperature in streams and rivers has been limited by sparse sampling in both space and time. Water temperature has typically been measured using a network of widely distributed instream gages, which record the temporal change of the bulk, or kinetic, temperature of the water (Tk) at specific locations. For example, the State of Washington (USA) recorded water quality conditions at 76 stations within the Puget Lowlands eco region, which contains 12,721 km of streams and rivers (Washington Department of Ecology, 1998). Such gages are sparsely distributed, are typically located only in larger streams and rivers, and give limited information about the spatial distribution of water temperature.

  19. Active condensation of water by plants

    Directory of Open Access Journals (Sweden)

    Prokhorov Alexey Anatolievich

    2013-10-01

    Full Text Available This paper is devoted to some peculiarities of water condensation on the surface of plants . Arguments in support of the hypothesis that in decreasing temperature of leaves and shoots below the dew point, the plant can actively condense moisture from the air, increasing the duration of dewfall are presented. Evening dewfall on plant surfaces begins before starting the formation of fog. Morning condensation continues for some time after the air temperature exceeds the dew point . The phenomenon in question is found everywhere, but it is particularly important for plants in arid ecosystems.

  20. Assimilation of water temperature and discharge data for ensemble water temperature forecasting

    Science.gov (United States)

    Ouellet-Proulx, Sébastien; Chimi Chiadjeu, Olivier; Boucher, Marie-Amélie; St-Hilaire, André

    2017-11-01

    Recent work demonstrated the value of water temperature forecasts to improve water resources allocation and highlighted the importance of quantifying their uncertainty adequately. In this study, we perform a multisite cascading ensemble assimilation of discharge and water temperature on the Nechako River (Canada) using particle filters. Hydrological and thermal initial conditions were provided to a rainfall-runoff model, coupled to a thermal module, using ensemble meteorological forecasts as inputs to produce 5 day ensemble thermal forecasts. Results show good performances of the particle filters with improvements of the accuracy of initial conditions by more than 65% compared to simulations without data assimilation for both the hydrological and the thermal component. All thermal forecasts returned continuous ranked probability scores under 0.8 °C when using a set of 40 initial conditions and meteorological forecasts comprising 20 members. A greater contribution of the initial conditions to the total uncertainty of the system for 1-dayforecasts is observed (mean ensemble spread = 1.1 °C) compared to meteorological forcings (mean ensemble spread = 0.6 °C). The inclusion of meteorological uncertainty is critical to maintain reliable forecasts and proper ensemble spread for lead times of 2 days and more. This work demonstrates the ability of the particle filters to properly update the initial conditions of a coupled hydrological and thermal model and offers insights regarding the contribution of two major sources of uncertainty to the overall uncertainty in thermal forecasts.

  1. Prediction of water temperature metrics using spatial modelling in ...

    African Journals Online (AJOL)

    Water temperature regime dynamics should be viewed regionally, where regional divisions have an inherent underpinning by an understanding of natural thermal variability. The aim of this research was to link key water temperature metrics to readily-mapped environmental surrogates, and to produce spatial images of ...

  2. Variability in estuarine water temperature gradients and influence on ...

    African Journals Online (AJOL)

    Variability in estuarine water temperature gradients and influence on the distribution of zooplankton: a biogeographical perspective. TH Wooldridge, SHP Deyzel. Abstract. Structure and variability of water temperature gradients and potential influence on distribution of two tropical zooplankters (the mysid Mesopodopsis ...

  3. Dataset of water activity measurements of alcohol:water solutions using a Tunable Diode Laser.

    Science.gov (United States)

    Allan, Matthew; Mauer, Lisa J

    2017-06-01

    The data presented in this article are related to the research article entitled "RH-temperature phase diagrams of hydrate forming deliquescent crystalline ingredients" (Allan and Mauer, 2017) [1]. The data are water activity measurements of alcohol:water solutions (methanol:water and ethanol:water solutions at varying molar ratios) at different temperatures collected using the Tunable Diode Laser by Decagon Devices. The measured water activities of ethanol:water solutions were correlated to the initial volumetric ratios to produce polynomial equations that can be used to calculate the needed initial volumetric ratios for water activity controlled solutions. The data sets and polynomial equations are provided to enable extended analyses and applications of the data and calculations for generating and using controlled water activity solutions containing alcohol. An example application of these data is described in the research article mentioned above.

  4. Modelling the effect of temperature, carbon dioxide, water activity and pH on growth and histamine formation by Morganella psychrotolerans

    DEFF Research Database (Denmark)

    Emborg, Jette; Dalgaard, Paw

    2008-01-01

    A mathematical model was developed to predict growth and histamine formation by Morganella psychrotolerans depending on temperature (0-20 degrees C), atmosphere (0-100% CO2), NaCl (0.0-6.0%) and pH (5.4-6.5). Data from experiments with both sterile tuna meat and Luria Bertani broth was used...

  5. 21 CFR 1250.42 - Water systems; constant temperature bottles.

    Science.gov (United States)

    2010-04-01

    ... and protected as to minimize the hazard of contamination of the water supply. (c) On all new or... containers used for storing or dispensing potable water shall be kept clean at all times and shall be... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Water systems; constant temperature bottles. 1250...

  6. Effect of water temperature on biofouling development in reverse osmosis membrane systems

    KAUST Repository

    Farhat, Nadia

    2016-07-14

    Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water.

  7. Experimental investigation of stabilization of flowing water temperature with a water-PCM heat exchanger

    Directory of Open Access Journals (Sweden)

    Charvat Pavel

    2014-03-01

    Full Text Available Experiments have been carried out in order to investigate the stabilization of water temperature with a water-PCM heat exchanger. The water-PCM heat exchanger was of a rather simple design. It was a round tube, through which the water flowed, surrounded with an annular layer of PCM. The heat exchanger was divided into one meter long segments (modules and the water temperature was monitored at the outlet of each of the segments. A paraffin-based PCM with the melting temperature of 42 °C was used in the experiments. The experimental set-up consisted of two water reservoirs kept at different temperatures, the water-PCM heat exchanger, PC controlled valves and a data acquisition system. As the first step a response to a step change in the water temperature at the inlet of the heat exchanger was investigated. Subsequently, a series of experiments with a square wave change of temperature at the inlet of the exchanger were carried out. The square wave temperature profile was achieved by periodic switching between the two water reservoirs. Several amplitudes and periods of temperature square wave were used. The results of experiments show that a water-PCM heat exchanger can effectively be used to stabilize the flowing water temperature when the inlet temperature changes are around the melting range of the PCM.

  8. A study on the physicochemical parameters for Penicillium expansum growth and patulin production: effect of temperature, pH, and water activity.

    Science.gov (United States)

    Tannous, Joanna; Atoui, Ali; El Khoury, André; Francis, Ziad; Oswald, Isabelle P; Puel, Olivier; Lteif, Roger

    2016-07-01

    Penicillium expansum is among the most ubiquitous fungi disseminated worldwide, that could threaten the fruit sector by secreting patulin, a toxic secondary metabolite. Nevertheless, we lack sufficient data regarding the growth and the toxigenesis conditions of this species. This work enables a clear differentiation between the favorable conditions to the P. expansum growth and those promising for patulin production. A mathematical model allowing the estimation of the P. expansum growth rate according to temperature, a W, and pH, was also developed. An optimal growth rate of 0.92 cm/day was predicted at 24°C with pH level of 5.1 and high a W level of 0.99. The model's predictive capability was tested successfully on artificial contaminated apples. This model could be exploited by apple growers and the industrialists of fruit juices in order to predict the development of P. expansum during storage and apple processing.

  9. Effects of water temperature change on immune function in surf clams, Mactra veneriformis (Bivalvia: Mactridae).

    Science.gov (United States)

    Yu, Jin Ha; Song, Jae Hee; Choi, Min Chul; Park, Sung Woo

    2009-09-01

    Surf clam, Mactra veneriformis is one of the crucial fishery resources in Korea. This study was performed to examine the immune functions of the surf clam under the stress of water temperature changes at 10 degrees C, 20 degrees C or 30 degrees C for 24h. Viable bacterial counts (VBC), total haemocyte count (THC), phagocytic activity, lysozyme activity, NRR times and SOD activity were assessed in three different water temperature groups. Clams held at 10 degrees C decreased in THC, lysozyme activity and NRR times, but phagocytic activity was increased. The highest temperature (30 degrees C) significantly increased in THC, whereas it decreased in phagocytic activity, lysozyme activity and NRR times. In clams maintained at 20 degrees C, phagocytic activity, lysozyme activity and NRR times were increased whereas THC was somewhat decreased with respect to clams held at 30 degrees C. However, water temperature changes did not elicit any alteration of VBC and SOD activity. The present study demonstrates that acute water temperature change affects the haemocytic and haemolymphatic functions, reducing immunosurveillance in stressed surf clam, M. veneriformis.

  10. Temperature influence on water transport in hardened cement pastes

    Energy Technology Data Exchange (ETDEWEB)

    Drouet, Emeline [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif sur Yvette Cedex (France); Poyet, Stéphane, E-mail: stephane.poyet@cea.fr [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif sur Yvette Cedex (France); Torrenti, Jean-Michel [Université Paris-Est, IFSTTAR, Département Matériaux & Structures, 14-52 boulevard Newton, F-77447 Marne la Vallée cedex 2 (France)

    2015-10-15

    Describing water transport in concrete is an important issue for the durability assessment of radioactive waste management reinforced concrete structures. Due to the waste thermal output such structures would be submitted to moderate temperatures (up to 80 °C). We have then studied the influence of temperature on water transport within hardened cement pastes of four different formulations. Using a simplified approach (describing only the permeation of liquid water) we characterized the properties needed to describe water transport (up to 80 °C) using dedicated experiments. For each hardened cement paste the results are presented and discussed.

  11. Effect of Climate Change on Water Temperature and ...

    Science.gov (United States)

    There is increasing evidence that our planet is warming and this warming is also resulting in rising sea levels. Estuaries which are located at the interface between land and ocean are impacted by these changes. We used CE-QUAL-W2 water quality model to predict changes in water temperature as a function of increasing air temperatures and rising sea level for the Yaquina Estuary, Oregon (USA). Annual average air temperature in the Yaquina watershed is expected to increase about 0.3 deg C per decade by 2040-2069. An air temperature increase of 3 deg C in the Yaquina watershed is likely to result in estuarine water temperature increasing by 0.7 to 1.6 deg C. Largest water temperature increases are expected in the upper portion of the estuary, while sea level rise may ameliorate some of the warming in the lower portion of the estuary. Smallest changes in water temperature are predicted to occur in the summer, and maximum changes during the winter and spring. Increases in air temperature may result in an increase in the number of days per year that the 7-day maximum average temperature exceeds 18 deg C (criterion for protection of rearing and migration of salmonids and trout) as well as other water quality concerns. In the upstream portion of the estuary, a 4 deg C increase in air temperature is predicted to cause an increase of 40 days not meeting the temperature criterion, while in the lower estuary the increase will depend upon rate of sea level rise (rang

  12. Flat Branch monitoring project: stream water temperature and sediment responses to forest cutting in the riparian zone

    Science.gov (United States)

    Barton D. Clinton; James M. Vose; Dick L. Fowler

    2010-01-01

    Stream water protection during timber-harvesting activities is of primary interest to forest managers. In this study, we examine the potential impacts of riparian zone tree cutting on water temperature and total suspended solids. We monitored stream water temperature and total suspended solids before and after timber harvesting along a second-order tributary of the...

  13. NOS CO-OPS Meteorological Data, Water Temperature, 6-Minute

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has Water Temperature data from NOAA NOS Center for Operational Oceanographic Products and Services (CO-OPS). WARNING: These preliminary data have not...

  14. NOAA NDBC SOS, 2006-present, sea_water_temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NDBC SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have sea_water_temperature data. Because of the nature of SOS requests,...

  15. Spatio-temporal attributes of water temperature and ...

    African Journals Online (AJOL)

    2013-01-20

    Jan 20, 2013 ... on macroinvertebrate assemblages, particularly in association with changing altitude within given southern African mountain drainage systems. Thus ... Keywords: Aquatic macroinvertebrates, water temperature, hydraulic biotypes, Drakensberg ..... altitudinal spatial density of monitoring sites be considered.

  16. Surface temperatures and temperature gradient features of the US Gulf Coast waters

    Science.gov (United States)

    Huh, O. K.; Rouse, L. J., Jr.; Smith, G. W.

    1977-01-01

    Satellite thermal infrared data on the Gulf of Mexico show that a seasonal cycle exists in the horizontal surface temperature structure. In the fall, the surface temperatures of both coastal and deep waters are nearly uniform. With the onset of winter, atmospheric cold fronts, which are accompanied by dry, low temperature air and strong winds, draw heat from the sea. A band of cooler water forming on the inner shelf expands, until a thermal front develops seaward along the shelf break between the cold shelf waters and the warmer deep waters of the Gulf. Digital analysis of the satellite data was carried out in an interactive mode using a minicomputer and software. A time series of temperature profiles illustrates the temporal and spatial changes in the sea-surface temperature field.

  17. Investigations of hot water temperature changes at the pipe outflow

    Science.gov (United States)

    Wojtkowiak, Janusz; Oleśkowicz-Popiel, Czesław

    2017-11-01

    In this paper a process of cold water withdrawing from hot water supply pipe systems without recirculation is considered. System of partial differential equations was used to describe the pipe and water temperature changes. An exact solution of a simplified form of the equations was obtained and validated experimentally. The exact solution was applied to calculate the hot water temperature changes at the pipe outflow. Calculations were done for typical pipe materials (PP, PE, Cu), different pipe diameters and lengths as well as for various water flow rates. It was shown that in order to obtain the required hot water temperature in the tap, there is necessary to withdrawn much more (even two times) water from the pipe in comparison to the pipe volume. The reason of such significant water wastes is a heat exchange between hot water flowing inside the pipe and the colder pipe walls. The results can be useful for optimal selection of hot water supply pipes as well as for making decision about applying of hot water recirculating systems.

  18. Water temperature modeling in the Garonne River (France

    Directory of Open Access Journals (Sweden)

    Larnier K.

    2010-10-01

    Full Text Available Stream water temperature is one of the most important parameters for water quality and ecosystem studies. Temperature can influence many chemical and biological processes and therefore impacts on the living conditions and distribution of aquatic ecosystems. Simplified models such as statistical models can be very useful for practitioners and water resource management. The present study assessed two statistical models – an equilibrium-based model and stochastic autoregressive model with exogenous inputs – in modeling daily mean water temperatures in the Garonne River from 1988 to 2005. The equilibrium temperature-based model is an approach where net heat flux at the water surface is expressed as a simpler form than in traditional deterministic models. The stochastic autoregressive model with exogenous inputs consists of decomposing the water temperature time series into a seasonal component and a short-term component (residual component. The seasonal component was modeled by Fourier series and residuals by a second-order autoregressive process (Markov chain with use of short-term air temperatures as exogenous input. The models were calibrated using data of the first half of the period 1988–2005 and validated on the second half. Calibration of the models was done using temperatures above 20 °C only to ensure better prediction of high temperatures that are currently at stake for the aquatic conditions of the Garonne River, and particularly for freshwater migrating fishes such as Atlantic Salmon (Salmo salar L.. The results obtained for both approaches indicated that both models performed well with an average root mean square error for observed temperatures above 20 °C that varied on an annual basis from 0.55 °C to 1.72 °C on validation, and good predictions of temporal occurrences and durations of three temperature threshold crossings linked to the conditions of migration and survival of Atlantic Salmon.

  19. Temperature stratification in a hot water tank with circulation pipe

    DEFF Research Database (Denmark)

    Andersen, Elsa

    1998-01-01

    The aim of the project is to investigate the change in temperature stratification due to the operation of a circulation pipe. Further, putting forward rules for design of pipe inlet in order not to disturb the temperature stratification in the hot water tank. A validated computer model based...

  20. Effects of temperature and growing seasons on crop water ...

    African Journals Online (AJOL)

    The crop water requirement (CWR) depends on several factors including temperature and growing seasons. This study investigated the effects of temperature and growing seasons on CWR in Saudi Arabia. Increase in temperature by 1°C increased the CWR by 1.9 - 2.9%, 1.9 – 3.0% and 2.2 – 3.8% for dates, alfalfa and ...

  1. Air- and stream-water-temperature trends in the Chesapeake Bay region, 1960-2014

    Science.gov (United States)

    Jastram, John D.; Rice, Karen C.

    2015-12-14

    Water temperature is a basic, but important, measure of the condition of all aquatic environments, including the flowing waters in the streams that drain our landscape and the receiving waters of those streams. Climatic conditions have a strong influence on water temperature, which is therefore naturally variable both in time and across the landscape. Changes to natural water-temperature regimes, however, can result in a myriad of effects on aquatic organisms, water quality, circulation patterns, recreation, industry, and utility operations. For example, most species of fish, insects, and other organisms, as well as aquatic vegetation, are highly dependent on water temperature. Warming waters can result in shifts in floral and faunal species distributions, including invasive species and pathogens previously unable to inhabit the once cooler streams. Many chemical processes are temperature dependent, with reactions occurring faster in warmer conditions, leading to degraded water quality as contaminants are released into waterways at greater rates. Circulation patterns in receiving waters, such as bays and estuaries, can change as a result of warmer inflows from streams, thereby affecting organisms in those receiving waters. Changes in abundance of some aquatic species and (or) degradation of water quality can reduce the recreational value of water bodies as waters are perceived as less desirable for water-related activities or as sportfish become less available for anglers. Finally, increasing water temperatures can affect industry and utilities as the thermal capacity is reduced, making the water less effective for cooling purposes.Chesapeake Bay is the largest estuary in the United States. Eutrophication, the enrichment of a water body with excess nutrients, has plagued the bay for decades and has led to extensive restoration efforts throughout the bay watershed. The warming of stream water can exacerbate eutrophication through increased release of nutrients from

  2. Temperature-programmed desorption of water and ammonia on ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Temperature-programmed desorption (TPD) of water and ammonia over. ZrO2 and sulphated ZrO2 prepared by different methods has been investigated for measuring strong acidity and acidity distribution on sulphated zirconia-type solid super-acid catalysts. The TPD of water provides a simple reliable method for ...

  3. Glycerin Reformation in High Temperature and Pressure Water

    Science.gov (United States)

    2012-01-01

    hygroscopic, while ethanol is renewable and non-toxic (94). Water has a detrimental effect on the reaction because soaps can be formed, which cause...Lavric, V. (2005) Delocalized organic pollutant destruction through a self-sustaining supercritical water oxidation process, Energy Conversion and...2012 2. REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Glycerin Reformation in High Temperature and Pressure Water

  4. Historical Change of Equilibrium Water Temperature in Japan

    Science.gov (United States)

    Miyamoto, H.

    2015-12-01

    Changes in freshwater ecosystems due to a climate change have been great concern for sustainable river basin management both for water resources utilization and ecological conservation. However, their impact seems to be difficult to evaluate because of wide variety of basin characteristics along a river network both in nature and social environment. This presentation uses equilibrium water temperature as a simple criterion index for evaluating the long-term changes of stream thermal environment due to the historical climate change in Japan. It examines, at first, the relationship between the equilibrium water temperature and the stream temperature observed for 7 years at a lower reach in the Ibo River, Japan. It analyzes, then, the seasonal and regional trends of the equilibrium water temperature change for the last 50 years at 133 meteorological station sites throughout Japan, discussing their rising or falling characteristics. The correlation analysis at the local reach of the Ibo River shows that the equilibrium water temperature has similar trend of change as the stream temperature. However, its value tends to be higher than the stream temperature in summer, while lower in winter. The onset of the higher equilibrium water temperature fluctuates annually from mid February to early April. This onset fluctuation at each spring could be influenced by the different amount of snow at the antecedent winter. The rising or falling trends of the equilibrium water temperature are analyzed both annually and seasonally through the regression analysis of the 133 sites in Japan. Consequently, the trends of the temperature change could be categorized by 12 patterns. As for the seasonal analysis, the results shows that there are many sites indicating the falling trend in spring and summer, and rising trends in autumn and winter. In particular, winter has the strong rising tendency throughout Japan. As for the regional analysis, the result illustrates the precise rationality; e

  5. Water Recycling removal using temperature-sensitive hydronen

    Energy Technology Data Exchange (ETDEWEB)

    Rana B. Gupta

    2002-10-30

    The overall objective of this project was to study the proposed Water Recycling/Removal Using Temperature-Sensitive Hydrogels. The main element of this technology is the design of a suitable hydrogel that can perform needed water separation for pulp and paper industry. The specific topics studied are to answer following questions: (a) Can water be removed using hydrogel from large molecules such as lignin? (b) Can the rate of separation be made faster? (c) What are the molecular interactions with hydrogel surface? (d) Can a hydrogel be designed for a high ionic strength and high temperature? Summary of the specific results are given.

  6. Soil Water and Temperature System (SWATS) Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, David R. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-04-01

    The soil water and temperature system (SWATS) provides vertical profiles of soil temperature, soil-water potential, and soil moisture as a function of depth below the ground surface at hourly intervals. The temperature profiles are measured directly by in situ sensors at the Central Facility and many of the extended facilities of the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Southern Great Plains (SGP) site. The soil-water potential and soil moisture profiles are derived from measurements of soil temperature rise in response to small inputs of heat. Atmospheric scientists use the data in climate models to determine boundary conditions and to estimate the surface energy flux. The data are also useful to hydrologists, soil scientists, and agricultural scientists for determining the state of the soil.

  7. Temperature of ground water at Philadelphia, Pennsylvania, 1979- 1981

    Science.gov (United States)

    Paulachok, Gary N.

    1986-01-01

    Anthropogenic heat production has undoubtedly caused increased ground-water temperatures in many parts of Philadelphia, Pennsylvania, as shown by temperatures of 98 samples and logs of 40 wells measured during 1979-81. Most sample temperatures were higher than 12.6 degrees Celsius (the local mean annual air temperature), and many logs depict cooling trends with depth (anomalous gradients). Heating of surface and shallow-subsurface materials has likely caused the elevated temperatures and anomalous gradients. Solar radiation on widespread concrete and asphalt surfaces, fossil-fuel combustion, and radiant losses from buried pipelines containing steam and process chemicals are believed to be the chief sources of heat. Some heat from these and other sources is transferred to deeper zones, mainly by conduction. Temperatures in densely urbanized areas are commonly highest directly beneath the land surface and decrease progressively with depth. Temperatures in sparsely urbanized areas generally follow the natural geothermal gradient and increase downward at about that same rate.

  8. Optimum hot water temperature for absorption solar cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R. [Dpto. Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad 30, 28911 Leganes, Madrid (Spain); Zacarias, A. [ESIME UPA, IPN, Av. de las Granjas 682, Col. Santa Catarina, 02550, D.F. Mexico (Mexico)

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  9. The effect of water deficit on body temperature during rugby.

    Science.gov (United States)

    Cohen, I; Mitchell, D; Seider, R; Kahn, A; Phillips, F

    1981-07-04

    Sweat losses, water deficits and changes in rectal temperature were measured in 13 first-league players during a rugby match. Changes in plasma volume, serum electrolyte and blood glucose levels were also determined. Rectal temperatures were markedly elevated after the match. Both temperatures reached levels which are known to be associated with an impairment of physical, mental and psychological function, and could have caused a deterioration in performance during the second half of the match. Body temperatures were high enough to have predisposed to aggressive behaviour. Increases in rectal temperature were related to water deficit. The small volumes of fluid ingested by the players just before and during the match suggest that they are unaware of the importance of preventing dehydration. Recommendations are made to reduce the risk of hyperthermia. Glucose and electrolyte supplementation is not required just before and during rugby.

  10. Climate and basin drivers of seasonal river water temperature dynamics

    Science.gov (United States)

    Laizé, Cédric L. R.; Bruna Meredith, Cristian; Dunbar, Michael J.; Hannah, David M.

    2017-06-01

    Stream water temperature is a key control of many river processes (e.g. ecology, biogeochemistry, hydraulics) and services (e.g. power plant cooling, recreational use). Consequently, the effect of climate change and variability on stream temperature is a major scientific and practical concern. This paper aims (1) to improve the understanding of large-scale spatial and temporal variability in climate-water temperature associations, and (2) to assess explicitly the influence of basin properties as modifiers of these relationships. A dataset was assembled including six distinct modelled climatic variables (air temperature, downward short-wave and long-wave radiation, wind speed, specific humidity, and precipitation) and observed stream temperatures for the period 1984-2007 at 35 sites located on 21 rivers within 16 basins (Great Britain geographical extent); the study focuses on broad spatio-temporal patterns, and hence was based on 3-month-averaged data (i.e. seasonal). A wide range of basin properties was derived. Five models were fitted (all seasons, winter, spring, summer, and autumn). Both site and national spatial scales were investigated at once by using multi-level modelling with linear multiple regressions. Model selection used multi-model inference, which provides more robust models, based on sets of good models, rather than a single best model. Broad climate-water temperature associations common to all sites were obtained from the analysis of the fixed coefficients, while site-specific responses, i.e. random coefficients, were assessed against basin properties with analysis of variance (ANOVA). All six climate predictors investigated play a role as a control of water temperature. Air temperature and short-wave radiation are important for all models/seasons, while the other predictors are important for some models/seasons only. The form and strength of the climate-stream temperature association vary depending on season and on water temperature. The

  11. Investigating the effect of surface water - groundwater interactions on stream temperature using Distributed temperature sensing and instream temperature model

    DEFF Research Database (Denmark)

    Karthikeyan, Matheswaran; Blemmer, Morten; Mortensen, Julie Flor

    2011-01-01

    Surface water–groundwater interactions at the stream interface influences, and at times controls the stream temperature, a critical water property driving biogeochemical processes. This study investigates the effects of these interactions on temperature of Stream Elverdamsåen in Denmark using the...

  12. FY16 ASME High Temperature Code Activities

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, M. J. [Chromtech Inc., Oak Ridge, TN (United States); Jetter, R. I. [R. I Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    One of the objectives of the ASME high temperature Code activities is to develop and validate both improvements and the basic features of Section III, Division 5, Subsection HB, Subpart B (HBB). The overall scope of this task is to develop a computer program to be used to assess whether or not a specific component under specified loading conditions will satisfy the elevated temperature design requirements for Class A components in Section III, Division 5, Subsection HB, Subpart B (HBB). There are many features and alternative paths of varying complexity in HBB. The initial focus of this task is a basic path through the various options for a single reference material, 316H stainless steel. However, the program will be structured for eventual incorporation all the features and permitted materials of HBB. Since this task has recently been initiated, this report focuses on the description of the initial path forward and an overall description of the approach to computer program development.

  13. Low temperature heating and high temperature cooling embedded water based surface heating and cooling systems

    CERN Document Server

    Babiak, Jan; Petras, Dusan

    2009-01-01

    This Guidebook describes the systems that use water as heat-carrier and when the heat exchange within the conditioned space is more than 50% radiant. Embedded systems insulated from the main building structure (floor, wall and ceiling) are used in all types of buildings and work with heat carriers at low temperatures for heating and relatively high temperature for cooling.

  14. Air-water temperature relationships in rivers and their prediction from environmental parameters

    Science.gov (United States)

    Johnson, M.; Wilby, R. L.; Toone, J.

    2012-12-01

    . The warmest sites on the rivers occur upstream of Dovedale and are affected by advected heat. Whilst there are strong relationships between air and water temperature, the regression models are site specific and differ substantially between sites across the network. In order to build a generic model, applicable at any site along the rivers, regression parameters were predicted from the environmental conditions along river reaches. Initial findings suggest a correlation between regression parameters and the percentage of vegetative and valley shade in upstream reaches. Our long-term aim is to use this technique to develop a generalised statistical model to help predict regions of river that are particularly susceptible to warming and areas that could be benefited from active management, such as the planting of riparian shade.

  15. Equatorial range limits of an intertidal ectotherm are more linked to water than air temperature.

    Science.gov (United States)

    Seabra, Rui; Wethey, David S; Santos, António M; Gomes, Filipa; Lima, Fernando P

    2016-10-01

    As climate change is expected to impose increasing thermal stress on intertidal organisms, understanding the mechanisms by which body temperatures translate into major biogeographic patterns is of paramount importance. We exposed individuals of the limpet Patella vulgata Linnaeus, 1758, to realistic experimental treatments aimed at disentangling the contribution of water and air temperature for the buildup of thermal stress. Treatments were designed based on temperature data collected at the microhabitat level, from 15 shores along the Atlantic European coast spanning nearly 20° of latitude. Cardiac activity data indicated that thermal stress levels in P. vulgata are directly linked to elevated water temperature, while high air temperature is only stressful if water temperature is also high. In addition, the analysis of the link between population densities and thermal regimes at the studied locations suggests that the occurrence of elevated water temperature may represent a threshold P. vulgata is unable to tolerate. By combining projected temperatures with the temperature threshold identified, we show that climate change will likely result in the westward expansion of the historical distribution gap in the Bay of Biscay (southwest France), and northward contraction of the southern range limit in south Portugal. These findings suggest that even a minor relaxing of the upwelling off northwest Iberia could lead to a dramatic increase in thermal stress, with major consequences for the structure and functioning of the intertidal communities along Iberian rocky shores. © 2016 John Wiley & Sons Ltd.

  16. Genetic Programming and Standardization in Water Temperature Modelling

    Directory of Open Access Journals (Sweden)

    Maritza Arganis

    2009-01-01

    Full Text Available An application of Genetic Programming (an evolutionary computational tool without and with standardization data is presented with the aim of modeling the behavior of the water temperature in a river in terms of meteorological variables that are easily measured, to explore their explanatory power and to emphasize the utility of the standardization of variables in order to reduce the effect of those with large variance. Recorded data corresponding to the water temperature behavior at the Ebro River, Spain, are used as analysis case, showing a performance improvement on the developed model when data are standardized. This improvement is reflected in a reduction of the mean square error. Finally, the models obtained in this document were applied to estimate the water temperature in 2004, in order to provide evidence about their applicability to forecasting purposes.

  17. Water temperature in irrigation return flow from the Upper Snake Rock watershed

    Science.gov (United States)

    Water returning to a river from an irrigated watershed could increase the water temperature in the river. The objective of this study was to compare the temperature of irrigation return flow water with the temperature of the diverted irrigation water. Water temperature was measured weekly in the mai...

  18. Description of Aspergillus flavus growth under the influence of different factors (water activity, incubation temperature, protein and fat concentration, pH, and cinnamon essential oil concentration) by kinetic, probability of growth, and time-to-detection models.

    Science.gov (United States)

    Kosegarten, Carlos E; Ramírez-Corona, Nelly; Mani-López, Emma; Palou, Enrique; López-Malo, Aurelio

    2017-01-02

    A Box-Behnken design was used to determine the effect of protein concentration (0, 5, or 10g of casein/100g), fat (0, 3, or 6g of corn oil/100g), aw (0.900, 0.945, or 0.990), pH (3.5, 5.0, or 6.5), concentration of cinnamon essential oil (CEO, 0, 200, or 400μL/kg) and incubation temperature (15, 25, or 35°C) on the growth of Aspergillus flavus during 50days of incubation. Mold response under the evaluated conditions was modeled by the modified Gompertz equation, logistic regression, and time-to-detection model. The obtained polynomial regression models allow the significant coefficients (p0.967) the studied mold responses. After 50days of incubation, every tested model system was classified according to the observed response as 1 (growth) or 0 (no growth), then a binary logistic regression was utilized to model A. flavus growth interface, allowing to predict the probability of mold growth under selected combinations of tested factors. The time-to-detection model was utilized to estimate the time at which A. flavus visible growth begins. Water activity, temperature, and CEO concentration were the most important factors affecting fungal growth. It was observed that there is a range of possible combinations that may induce growth, such that incubation conditions and the amount of essential oil necessary for fungal growth inhibition strongly depend on protein and fat concentrations as well as on the pH of studied model systems. The probabilistic model and the time-to-detection models constitute another option to determine appropriate storage/processing conditions and accurately predict the probability and/or the time at which A. flavus growth occurs. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Development and validation of a drinking water temperature model in domestic drinking water supply systems

    NARCIS (Netherlands)

    Zlatanovic, Ljiljana; Moerman, Andreas; Hoek, van der Jan Peter; Vreeburg, Jan; Blokker, Mirjam

    2017-01-01

    Domestic drinking water supply systems (DDWSs) are the final step in the delivery of drinking water to consumers. Temperature is one of the rate-controlling parameters for many chemical and microbiological processes and is, therefore, considered as a surrogate parameter for water quality

  20. Development of solid electrolytes for water electrolysis at intermediate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A.; Kopitzke, R.W. [Florida Solar Energy Center, Cape Canaveral, FL (United States)

    1995-09-01

    If an electrolyzer could operate at higher temperatures, several benefits would accrue. The first is that the thermodynamic electrical energy requirement to drive the reaction would be reduced. Supplying the total enthalpy of reaction at any temperature involves a combination of electrical and thermal energy inputs. Because of the positive entropy associated with water decomposition, the thermal contribution increases as temperature rises, allowing the free energy requirement to decrease. Thus the open circuit voltage, V{sub oc}, for water splitting drops as temperature rises. At room temperature, V{sub oc} for water decomposition is 1.229 V. At 400{degrees}C, voltage requirement has dropped to 1.1 V; at 1000{degrees}C, it is only 0.92 V. Since electricity is a more expensive form of energy on a btu basis, the more energy taken from the thermal surroundings the better. Moreover, this thermal energy content could be solar-derived. While the cost of solar thermal energy varies in the range of $360-900/peak kilowatt, the installed cost of photovoltaic electricity is in the range of $4,000-5,000/peak kilowatt. Thus if one is compelled to erect an array of photovoltaic panels to generate the e.m.f. necessary to split water, substituting as much area with thermal collectors as possible represents a substantial cost savings.

  1. Study of the combined effect of temperature, pH and water activity on the radial growth rate of the white-rot basidiomycete Physisporinus vitreus by using a hyphal growth model

    CERN Document Server

    Fuhr, M J; Schubert, M; Schwarze, F W M R; Herrmann, H J

    2011-01-01

    The present work investigates environmental effects on the growth of fungal colonies of P. vitreus by using a lattice-free discrete modelling approach called FGM (Fuhr et al. (2010), arXiv:1101.1747), in which hyphae and nutrients are considered as discrete structures. A discrete modelling approach allows studying the underlying mechanistic rule concerning the basic architecture and dynamic of fungal networks on the scale of a single colony. By comparing simulations of the FGM with laboratory experiments of growing fungal colonies on malt extract agar we show that combined effect of temperature, pH and water activity on the radial growth rate of a fungal colony on a macroscopic scale may be explained by a power law for the growth costs of hyphal expansion on a microscopic scale. The information about the response of the fungal mycelium on a microscopic scale to environmental conditions is essential to simulate its behavior in complex structure substrates such as wood, where the impact of the fungus to the woo...

  2. Solar High Temperature Water-Splitting Cycle with Quantum Boost

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Robin [SAIC; Davenport, Roger [SAIC; Talbot, Jan [UCSD; Herz, Richard [UCSD; Genders, David [Electrosynthesis Co.; Symons, Peter [Electrosynthesis Co.; Brown, Lloyd [TChemE

    2014-04-25

    A sulfur family chemical cycle having ammonia as the working fluid and reagent was developed as a cost-effective and efficient hydrogen production technology based on a solar thermochemical water-splitting cycle. The sulfur ammonia (SA) cycle is a renewable and sustainable process that is unique in that it is an all-fluid cycle (i.e., with no solids handling). It uses a moderate temperature solar plant with the solar receiver operating at 800°C. All electricity needed is generated internally from recovered heat. The plant would operate continuously with low cost storage and it is a good potential solar thermochemical hydrogen production cycle for reaching the DOE cost goals. Two approaches were considered for the hydrogen production step of the SA cycle: (1) photocatalytic, and (2) electrolytic oxidation of ammonium sulfite to ammonium sulfate in aqueous solutions. Also, two sub-cycles were evaluated for the oxygen evolution side of the SA cycle: (1) zinc sulfate/zinc oxide, and (2) potassium sulfate/potassium pyrosulfate. The laboratory testing and optimization of all the process steps for each version of the SA cycle were proven in the laboratory or have been fully demonstrated by others, but further optimization is still possible and needed. The solar configuration evolved to a 50 MW(thermal) central receiver system with a North heliostat field, a cavity receiver, and NaCl molten salt storage to allow continuous operation. The H2A economic model was used to optimize and trade-off SA cycle configurations. Parametric studies of chemical plant performance have indicated process efficiencies of ~20%. Although the current process efficiency is technically acceptable, an increased efficiency is needed if the DOE cost targets are to be reached. There are two interrelated areas in which there is the potential for significant efficiency improvements: electrolysis cell voltage and excessive water vaporization. Methods to significantly reduce water evaporation are

  3. Effects of water velocity on activity of juvenile striped bass

    Energy Technology Data Exchange (ETDEWEB)

    Bowles, R.R.; Griffith, J.S.; Coutant, C.C.

    1976-07-01

    The swimming activity of juvenile striped bass (Morone saxatilis Walbaum) 8 to 80 mm long was investigated in a test chamber simulating, on a small scale, a fixed-screen cooling water intake structure. As water velocity increased from 0 to 30 cm/sec area and distance traveled by juvenile bass 10 to 80 mm long decreased. However, as water velocity increased from 0 to 3 cm/sec the area and distance covered by larval bass increased. The presence of food increased the activity of larval bass, but decreased the activity of juveniles. Area ranged by striped bass at test velocities ranging from 0 to 30 cm/sec increased in proportion to body length. Juvenile striped bass tested at acclimation temperatures between 20 and 5/sup 0/C experienced a 30% reduction of activity. Activity was also reduced as temperature increased from 20 to 30/sup 0/C.

  4. Effect of water temperature on biofouling development in reverse osmosis membrane systems.

    Science.gov (United States)

    Farhat, N M; Vrouwenvelder, J S; Van Loosdrecht, M C M; Bucs, Sz S; Staal, M

    2016-10-15

    Understanding the factors that determine the spatial and temporal biofilm development is a key to formulate effective control strategies in reverse osmosis membrane systems for desalination and wastewater reuse. In this study, biofilm development was investigated at different water temperatures (10, 20, and 30 °C) inside a membrane fouling simulator (MFS) flow cell. The MFS studies were done at the same crossflow velocity with the same type of membrane and spacer materials, and the same feed water type and nutrient concentration, differing only in water temperature. Spatially resolved biofilm parameters such as oxygen decrease rate, biovolume, biofilm spatial distribution, thickness and composition were measured using in-situ imaging techniques. Pressure drop (PD) increase in time was used as a benchmark as to when to stop the experiments. Biofilm measurements were performed daily, and experiments were stopped once the average PD increased to 40 mbar/cm. The results of the biofouling study showed that with increasing feed water temperature (i) the biofilm activity developed faster, (ii) the pressure drop increased faster, while (iii) the biofilm thickness decreased. At an average pressure drop increase of 40 mbar/cm over the MFS for the different feed water temperatures, different biofilm activities, structures, and quantities were found, indicating that diagnosis of biofouling of membranes operated at different or varying (seasonal) feed water temperatures may be challenging. Membrane installations with a high temperature feed water are more susceptible to biofouling than installations fed with low temperature feed water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Efficiency and temperature dependence of water removal by membrane dryers

    Science.gov (United States)

    Leckrone, K. J.; Hayes, J. M.

    1997-01-01

    The vapor pressure of water in equilibrium with sorption sites within a Nafion membrane is given by log P(WN) = -3580/T + 10.01, where P(WN) is expressed in Torr and T is the membrane temperature, in kelvin. The efficiency of dryers based on selective permeation of water through Nafion can thus be enhanced by cooling the membrane. Residual water in effluents exceeds equilibrium levels if insufficient time is allowed for water to diffuse to the membrane surface as gas passes through the dryer. For tubular configurations, this limitation can be avoided if L > or = Fc(10(3.8)/120 pi D), where L is the length of the tubular membrane, in centimeters, Fc is the gas flow rate, in mL/ min, and D is the diffusion coefficient for water in the carrier gas at the operating temperature of the dryer, in cm2/s. An efficient dryer that at room temperature dries gas to a dew point of -61 degrees C is described; the same dryer maintained at 0 degrees C yields a dew point of -80 degrees C and removes water as effectively as Mg(ClO4)2 or a dry ice/acetone slush. The use of Nafion membranes to construct devices capable of delivering gas streams with low but precisely controlled humidities is discussed.

  6. Water vaporization promotes coseismic fluid pressurization and buffers temperature rise

    NARCIS (Netherlands)

    Chen, Jianye|info:eu-repo/dai/nl/370819071; Niemeijer, André|info:eu-repo/dai/nl/370832132; Yao, Lu; Ma, Shengli

    2017-01-01

    We investigated the frictional properties of carbonate-rich gouge layers at a slip rate of 1.3 m/s, under dry and water-saturated conditions, while monitoring temperature at different locations on one of the gouge-host rock interfaces. All experiments showed a peak frictional strength of 0.4–0.7,

  7. Spatio-temporal attributes of water temperature and ...

    African Journals Online (AJOL)

    The study demonstrates that decreasing water temperatures, both spatially (with increasing altitude) and seasonally (from summer to winter), and/or decreasing diversity of hydraulic biotypes associated with stream-channel narrowing in Drakensberg rivers/streams, are associated with a general decrease in the absolute ...

  8. Possible effects of regulating hydroponic water temperature on plant ...

    African Journals Online (AJOL)

    Yomi

    2010-12-29

    Dec 29, 2010 ... production of antioxidants in cells exposed to heat stress. EFFECTS OF REGULATING HYDROPONIC WATER. TEMPERATURE ON NUTRIENT UPTAKE AND. ACCUMULATION IN PLANT TISSUES. Plant nutrients have a great potential for increasing yield and are capable of promoting plant growth ( ...

  9. Temperature-programmed desorption of water and ammonia on ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 115; Issue 4. Temperature-programmed desorption of water and ammonia on sulphated zirconia catalysts for ... Author Affiliations. Vasant R Choudhary1 Abhijeet J Karkamkar1. Chemical Engineering Division, National Chemical Laboratory, Pune 411 008, India ...

  10. Defluoridation of drinking water with pottery: effect of firing temperature.

    Science.gov (United States)

    Hauge, S; Osterberg, R; Bjorvatn, K; Selvig, K A

    1994-12-01

    Excessive fluoride (F) in drinking water should be removed, but simple, inexpensive methods of fluoride removal are not readily available. This study examines the F(-)-binding capacity of clay and clayware, especially the effect of the firing temperature on the F(-)-binding process. A series of pots were made from ordinary potter's clay and fired at 500-1000 degrees C. Likewise, small clay bricks were fired and then crushed and sieved. NaF solutions containing 10 mg/l F- (10 ppm F-) were prepared. Suitable aliquots of the solutions were poured into clay pots or exposed to powdered clayware. Samples were taken at storage periods of 30 min to 20 days and analyzed for F- by ion-selective electrodes. The rate and capacity of F(-)-binding in the clayware varied with the firing temperature. Clay fired at approximately 600 degrees C was most effective. Temperatures over 700 degrees C caused a decline in F(-)-binding, and pottery fired at 900 degrees C and above seemed unable to remove F- from water. Pots fired at 500 degrees C or less cracked in water. The findings indicate that clayware, fired at an optimal temperature, may be of practical value for partial defluoridation of drinking water.

  11. Effects of Hot Water Treatment and Temperature on Seedling ...

    African Journals Online (AJOL)

    An experiment was conducted at the Faculty of Agriculture, University of Maiduguri, to study the effect of hot water treatment and temperature on the morphological characteristics of Arabic gum. The experiment was laid out in a Randomized Complete Block Design in a factorial arrangement. The treatments included a ...

  12. Enzyme Activities in Waste Water and Activated Sludge

    DEFF Research Database (Denmark)

    Nybroe, Ole; Jørgensen, Per Elberg; Henze, Mogens

    1992-01-01

    The purpose of the present study was to evaluate the potential of selected enzyme activity assays to determine microbial abundance and heterotrophic activity in waste water and activated sludge. In waste water, esterase and dehydrogenase activities were found to correlate with microbial abundance...

  13. The oxidant-antioxidant equilibrium, activities of selected lysosomal enzymes and activity of acute phase protein in peripheral blood of 18-year-old football players after aerobic cycle ergometer test combined with ice-water immersion or recovery at room temperature.

    Science.gov (United States)

    Sutkowy, Paweł; Woźniak, Alina; Boraczyński, Tomasz; Boraczyński, Michał; Mila-Kierzenkowska, Celestyna

    2017-02-01

    The goal of the study was to evaluate the effect of an aerobic exercise bout followed by ice-water immersion or recovery at room temperature on the redox state, activities of selected lysosomal enzymes and activity of α1-antitrypsin (AAT) in the blood of healthy sportsmen. Eleven amateur football players aged 18 were randomly assigned to two similar 30-min aerobic cycle ergometer tests followed by a recovery at room temperature (20 °C; Experiment 1) or ice-water immersion (3 °C, 5 min; Experiment 2). Peripheral blood was collected three times during both study experiments: before (baseline), as well as 20 and 40 min after the recovery or immersion. The concentrations of thiobarbituric acid reactive substances in blood plasma (plTBARS) and erythrocytes (erTBARS) were measured. The erythrocytic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were also determined. In the blood serum, the activities of acid phosphatase (AcP), arylsulphatase (ASA), cathepsin D (CTS D) and AAT were evaluated. The activities of AcP, ASA, CTS D and AAT changed similarly during both experiments. The GPx activity decreased 40 min after the exercise/recovery compared to the baseline activity and was lower than 40 min after the exercise/immersion. The exercise followed by the recovery or immersion had no significant effect on the serum lysosomal and AAT activities in the studied men. The exercise/recovery reduced the hydrogen peroxide concentration in the men's erythrocytes, however the exercise/immersion demonstrated the opposite effect. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton

    Science.gov (United States)

    Rasconi, Serena; Gall, Andrea; Winter, Katharina; Kainz, Martin J.

    2015-01-01

    Climate change scenarios predict that lake water temperatures will increase up to 4°C and rainfall events will become more intense and frequent by the end of this century. Concurrently, supply of humic substances from terrestrial runoff is expected to increase, resulting in darker watercolor (“brownification”) of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning. We tested the hypothesis that higher water temperature (+3°C) and brownification will, a) cause plankton community composition to shift toward small sized phytoplankton and cyanobacteria, and, b) extend the length of the growing season entailing higher phytoplankton production later in the season. We demonstrate that the 3°C increase of water temperature favored the growth of heterotrophic bacteria and small sized autotrophic picophytoplankton cells with significantly higher primary production during warmer fall periods. However, 3X darker water (effect of brownification) caused no significant changes in the plankton community composition or functioning relative to control conditions. Our findings reveal that increased temperature change plankton community structure by favoring smaller sized species proliferation (autotrophic phytoplankton and small size cladocerans), and increase primary productivity and community turnover. Finally, results of this multi-seasonal experiment suggest that warming by 3°C in aquatic ecosystems of low trophic state may cause planktonic food web functioning to become more dominated by fast growing, r-trait species (i.e., small sizes and rapid development). PMID:26461029

  15. Technologies for Upgrading Light Water Reactor Outlet Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Daniel S. Wendt; Piyush Sabharwall; Vivek Utgikar

    2013-07-01

    Nuclear energy could potentially be utilized in hybrid energy systems to produce synthetic fuels and feedstocks from indigenous carbon sources such as coal and biomass. First generation nuclear hybrid energy system (NHES) technology will most likely be based on conventional light water reactors (LWRs). However, these LWRs provide thermal energy at temperatures of approximately 300°C, while the desired temperatures for many chemical processes are much higher. In order to realize the benefits of nuclear hybrid energy systems with the current LWR reactor fleets, selection and development of a complimentary temperature upgrading technology is necessary. This paper provides an initial assessment of technologies that may be well suited toward LWR outlet temperature upgrading for powering elevated temperature industrial and chemical processes during periods of off-peak power demand. Chemical heat transformers (CHTs) are a technology with the potential to meet LWR temperature upgrading requirements for NHESs. CHTs utilize chemical heat of reaction to change the temperature at which selected heat sources supply or consume thermal energy. CHTs could directly utilize LWR heat output without intermediate mechanical or electrical power conversion operations and the associated thermodynamic losses. CHT thermal characteristics are determined by selection of the chemical working pair and operating conditions. This paper discusses the chemical working pairs applicable to LWR outlet temperature upgrading and the CHT operating conditions required for providing process heat in NHES applications.

  16. WC as a non-platinum hydrogen evolution electrocatalyst for high temperature PEM water electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik

    2012-01-01

    Tungsten carbide (WC) nanopowder was tested as a non-platinum cathode electrocatalyst for polymer electrolyte membrane (PEM) water electrolysers, operating at elevated temperatures. It was prepared in thermal plasma reactor with confined plasma jet from WO3 precursor in combination with CH4...... carburizing agent. The results of the investigation showed that the activity of tungsten carbide as cathode electrocatalyst increases significantly with temperature and this effect is more pronounced than for platinum, especially, at 150 °C....

  17. Simulating future water temperatures in the North Santiam River, Oregon

    Science.gov (United States)

    Buccola, Norman; Risley, John C.; Rounds, Stewart A.

    2016-01-01

    A previously calibrated two-dimensional hydrodynamic and water-quality model (CE-QUAL-W2) of Detroit Lake in western Oregon was used in conjunction with inflows derived from Precipitation-Runoff Modeling System (PRMS) hydrologic models to examine in-lake and downstream water temperature effects under future climate conditions. Current and hypothetical operations and structures at Detroit Dam were imposed on boundary conditions derived from downscaled General Circulation Models in base (1990–1999) and future (2059–2068) periods. Compared with the base period, future air temperatures were about 2 °C warmer year-round. Higher air temperature and lower precipitation under the future period resulted in a 23% reduction in mean annual PRMS-simulated discharge and a 1 °C increase in mean annual estimated stream temperatures flowing into the lake compared to the base period. Simulations incorporating current operational rules and minimum release rates at Detroit Dam to support downstream habitat, irrigation, and water supply during key times of year resulted in lower future lake levels. That scenario results in a lake level that is above the dam’s spillway crest only about half as many days in the future compared to historical frequencies. Managing temperature downstream of Detroit Dam depends on the ability to blend warmer water from the lake’s surface with cooler water from deep in the lake, and the spillway is an important release point near the lake’s surface. Annual average in-lake and release temperatures from Detroit Lake warmed 1.1 °C and 1.5 °C from base to future periods under present-day dam operational rules and fill schedules. Simulated dam operations such as beginning refill of the lake 30 days earlier or reducing minimum release rates (to keep more water in the lake to retain the use of the spillway) mitigated future warming to 0.4 and 0.9 °C below existing operational scenarios during the critical autumn spawning period for endangered

  18. WATER ACTIVITY DATA ASSESSMENT TO BE USED IN HANFORD WASTE SOLUBILITY CALCULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    DISSELKAMP RS

    2011-01-06

    The purpose of this report is to present and assess water activity versus ionic strength for six solutes:sodium nitrate, sodium nitrite, sodium chloride, sodium carbonate, sodium sulfate, and potassium nitrate. Water activity is given versus molality (e.g., ionic strength) and temperature. Water activity is used to estimate Hanford crystal hydrate solubility present in the waste.

  19. The combined effect of pasteurization intensity, water activity, pH and incubation temperature on the survival and outgrowth of spores of Bacillus cereus and Bacillus pumilus in artificial media and food products.

    Science.gov (United States)

    Samapundo, S; Heyndrickx, M; Xhaferi, R; de Baenst, I; Devlieghere, F

    2014-07-02

    The objective of the study was to evaluate the combined effects of pasteurization intensity (no heat treatment and 10 min at 70, 80 and 90 °C), water activity (aw) (0.960-0.990), pH (5.5-7.0) and storage temperature (7 and 10 °C) on the survival and outgrowth of psychrotolerant spores of Bacillus cereus FF119b and Bacillus pumilus FF128a. The experiments were performed in both artificial media and a validation was performed on real food products (cream, béchamel sauce and mixed vegetable soup). It was determined that in general, heat treatments of 10 min at 70 °C or 80 °C activated the spores of both B. cereus FF119b and B. pumilus FF128a, resulting in faster outgrowth compared to native (non-heat treated) spores. A pasteurization treatment of 10 min at 90 °C generally resulted in the longest lag periods before outgrowth of both isolates. Some of the spores were inactivated by this heat treatment, with more inactivation being observed the lower the pH value of the heating medium. Despite this, it was also observed that under some conditions the remaining (surviving) spores were actually activated as their outgrowth took place after a shorter period of time compared to native non-heated spores. While the response of B. cereus FF119b to the pasteurization intensity in cream and béchamel sauce was similar to the trends observed in the artificial media at 10 °C, in difference, outgrowth was only observed at 7 °C in both products when the spores had been heated for 10 min at 80 °C. Moreover, no inactivation was observed in cream or béchamel sauce when the spores were heated for 10 min at 90 °C in these two products. This was attributed to the protective effect of fat in the cream and the ingredients in the béchamel sauce. The study provides some insight into the potential microbial (stability and safety) consequences of the current trend towards milder heat treatments which is being pursued in the food industry. Copyright © 2014. Published by Elsevier B.V.

  20. Early Water Stress Detection Using Leaf-Level Measurements of Chlorophyll Fluorescence and Temperature Data

    Directory of Open Access Journals (Sweden)

    Zhuoya Ni

    2015-03-01

    Full Text Available The purpose of this paper was to investigate the early water stress in maize using leaf-level measurements of chlorophyll fluorescence and temperature. In this study, a series of diurnal measurements, such as leaf chlorophyll fluorescence (Fs, leaf spectrum, temperature and photosynthetically active radiation (PAR, were conducted for maize during gradient watering and filled watering experiments. Fraunhofer Line Discriminator methods (FLD and 3FLD were used to obtain fluorescence from leaves spectrum. This simulated work using the SCOPE model demonstrated the variations in fluorescence and temperature in stress levels expressed by different stress factors. In the field measurement, the gradient experiment revealed that chlorophyll fluorescence decreased for plants with water stress relative to well-water plants and Tleaf-Tair increased; the filled watering experiment stated that chlorophyll fluorescence of maize under water stress were similar to those of maize under well-watering condition. In addition, the relationships between the Fs, retrieved fluorescence, Tleaf-Tair and water content were analyzed. The Fs determination resulted to the best coefficients of determination for the normalized retrieved fluorescence FLD/PAR (R2 = 0.54, Tleaf-Tair (R2 = 0.48 and water content (R2 = 0.71. The normalized retrieved fluorescence yielded a good coefficient of determination for Tleaf-Tair (R2 = 0.48. This study demonstrated that chlorophyll fluorescence could reflect variations in the physiological states of plants during early water stress, and leaf temperature confirmed the chlorophyll fluorescence analysis results and improved the accuracy of the water stress detection.

  1. Study on the method of maintaining bathtub water temperature

    Science.gov (United States)

    Wang, Xiaoyan

    2017-05-01

    In order to make the water temperature constant and the spillage to its minimum, we use finite element method and grid transformation and have established an optimized model for people in the bathtub both in time and space, which is based on theories of heat convection and heat conduction and three-dimensional second-order equation. For the first question, we have worked out partial differential equations for three-dimensional heat convection. In the meantime, we also create an optimized temperature model in time and space by using initial conditions and boundary conditions. For the second question we have simulated the shape and volume of the tub and the human gestures in the tub based on the first question. As for the shape and volume of the tub, we draw conclusion that the tub whose surface area is little contains water with higher temperature. Thus, when we are designing bathtubs we can decrease the area so that we'll have less loss heat. For different gestures when people are bathing, we have found that gestures have no obvious influence on variations of water temperature. Finally, we did some simulating calculations, and did some analysis on precision and sensitivity

  2. Water temperature and pH influence olfactory sensitivity to pre ...

    Indian Academy of Sciences (India)

    This shows that circulatory androgens exert an activational effect on olfactory receptors of male fish. Wild caught tubercular males and androgen implanted juvenile males exhibit a high responsiveness to steroid sulphate at the water temperature and pH which fish experience during the pre-spawning phase. The male's ...

  3. Engineering Water Analysis Laboratory Activity.

    Science.gov (United States)

    Schlenker, Richard M.

    The purposes of water treatment in a marine steam power plant are to prevent damage to boilers, steam-operated equipment, and steam and condensate lives, and to keep all equipment operating at the highest level of efficiency. This laboratory exercise is designed to provide students with experiences in making accurate boiler water tests and to…

  4. Achieving low return temperature for domestic hot water preparation by ultra-low-temperature district heating

    DEFF Research Database (Denmark)

    Yang, Xiaochen; Svendsen, Svend

    2017-01-01

    to achieve high efficiency of the ULTDH system, the return temperature should be as low as possible. For the energy-efficient buildings in the future, it is feasible to use ULTDH to cover the space heating demand. However, considering the comfort and hygiene requirements of domestic hot water (DHW...

  5. Seasonal water parameters of active and resting nursery ponds on ...

    African Journals Online (AJOL)

    Water quality parameters from active and resting nursery ponds were taken in both dry and wet seasons at the model fish farms, University of Ibadan. Temperature, turbidity, dissolved oxygen (D.O.), free carbon dioxide, pH, total alkalinity, total hardness and nitrite were examined to determine the suitable conditions of the ...

  6. Temperature Effect on the Nanostructure of SDS Micelles in Water.

    Science.gov (United States)

    Hammouda, Boualem

    2013-01-01

    Sodium dodecyl sulfate (SDS) surfactants form micelles when dissolved in water. These are formed of a hydrocarbon core and hydrophilic ionic surface. The small-angle neutron scattering (SANS) technique was used with deuterated water (D2O) in order to characterize the micelle structure. Micelles were found to be slightly compressed (oblate ellipsoids) and their sizes shrink with increasing temperature. Fits of SANS data to the Mean Spherical Approximation (MSA) model yielded a calculated micelle volume fraction which was lower than the SDS surfactant (sample mixing) volume fraction; this suggests that part of the SDS molecules do not participate in micelle formation and remain homogeneously mixed in the solvent. A set of material balance equations allowed the estimation of the SDS fraction in the micelles. This fraction was found to be high (close to one) except for samples around 1 % SDS fraction. The micelle aggregation number was found to decrease with increasing temperature and/or decreasing SDS fraction.

  7. The “Puzzle” of Water Behavior at Low Temperature

    Directory of Open Access Journals (Sweden)

    José Teixeira

    2010-09-01

    Full Text Available Thermodynamic and transport properties of liquid water are not fully understood despite a large amount of research work both experimental and theoretical. The maximum of density and the enhanced anomalies observed at low temperatures are at the origin of several models that, in some cases, predict specific and unique behavior such as spinodal lines or critical points. We show that a careful analysis of the neutron quasi-elastic scattering data, both the incoherent spectra and the dynamic of the partials, is compatible with a polymer-like model, where the hydrogen bond dynamics explains the behavior of water in the non-accessible temperature region extending from −30° C to the glass transition.

  8. Viscosity of water-in-oil emulsions. Variation with temperature and water volume fraction

    Energy Technology Data Exchange (ETDEWEB)

    Farah, Marco A.; Caldas, Jorge Navaes [Petroleo Brasileiro S.A., Rua General Canabarro, 500, Maracana, Rio, CEP 2057-900 (Brazil); Oliveira, Roberto C. [Petroleo Brasileiro S.A., Cenpes, Cidade Universitaria (Brazil); Rajagopal, Krishnaswamy [LATCA-Laboratorio de Termodinamica e Cinetica Aplicada-Escola de Quimica, Departamento de Engenharia Quimica, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitaria, C.P. 68452, CEP 21949-900, Rio de Janeiro (Brazil)

    2005-09-15

    Water-in-oil emulsions are important in the petroleum industry in production operations, where the water content of the emulsion can be as high as 60% in volume, also in petroleum refining operations where generally the water content is low. The effective viscosity of water-in-oil emulsions depends mainly on the volume fraction of dispersed phase and temperature, along with several minor effects, such as shear rate, average droplet size, droplet size distribution, viscosity and density of oil. Using six different crude oils, the effective viscosities of several synthetic water-in-oil emulsions are measured at atmospheric pressure using a dynamic viscosimeter for different shear rates, temperatures and volume fractions of the dispersed phase. The ASTM equation, method D-341, for describing viscosity as a function of temperature is extended to include the variation of dispersed phase volume fraction. The proposed equation gives good correlation between the measured viscosities of water-in-oil emulsions as a function of temperature and the volume fraction of water.

  9. Daphnia magna fitness during low food supply under different water temperature and brownification scenarios

    Directory of Open Access Journals (Sweden)

    Andrea Gall

    2016-11-01

    Full Text Available Much of our current knowledge about non-limiting dietary carbon supply for herbivorous zooplankton is based on experimental evidence and typically conducted at ~1 mg C L-1 and ~20°C. Here we ask how low supply of dietary carbon affects somatic growth, reproduction, and survival of Daphnia magna and test effects of higher water temperature (+3 °C relative to ambient and brownification (3X higher than natural water color; both predicted effects of climate change during fall cooling. We predicted that even at very low carbon supply (~5µg C L-1, higher water temperature and brownification will allow D. magna to increase its fitness. Neonates (<24 h old were incubated with lake seston for 4 weeks (October-November 2013 in experimental bottles submerged in outdoor mesocosms to explore effects of warmer and darker water. Higher temperature and brownification did not significantly affect food quality, as assessed by its fatty acid composition. Daphnia exposed to both increased temperature and brownification had highest somatic growth and were the only that reproduced, and higher temperature caused the highest Daphnia survival success. These results suggest that even under low temperature and thus lower physiological activity, low food quantity is more important than its quality for D. magna fitness.

  10. Soil and water temperature effects on the fluvial erosion of cohesive sediments

    Science.gov (United States)

    Akinola, A.; Wynn-Thompson, T.; Olgun, G.

    2016-12-01

    Sediment is one of the leading causes of water quality impairment in US streams and rivers (Wood and Armitage 1997; USEPA 2000; Bryce et al., 2010). Although sediment mobilization from the and transport through fluvial systems is a natural process, human activities, as a result of urbanization and climate change, alter the natural hydrologic and hydraulic characteristic of watersheds, leading to extreme erosion and sedimentation. Apart from higher flows, however, urbanization leads to elevated stream temperatures and, in combination with other anthropogenic influences such as hydropower operations, reservoir discharges and industrial cooling water, result in water and soil temperatures well above the expected seasonal temperature regime. In laboratory experiments, a higher water temperature was positively correlated with erosion rates (Grissinger, 1966; Cristensen and Das 1974; Parks, 2012) but this phenomenon is still poorly understood. Additionally, the effect of soil temperature on the fluvial erosion of cohesive soils has never been studied before; therefore, this research explores the relationship between soil and water temperature on cohesive soil erosion rate. Remolded montmorillonite, vermiculite and illite/kaolinite-dominated soils were tested in an 8 m x 1 m x 0.4 m recirculating flume at four combinations of soil temperatures and water temperatures (40C water and 40C soil, 40C water and 150C soil, 250C water and 250C soil, 250C water and 400C soil) representing typical winter and summer field conditions, as well as increased soil temperatures due to contact with urban infrastructure, such as bridge piers or foundations. Soils were compacted at their respective maximum dry density and optimum moisture content, based on Proctor tests (ASTM D698) and then eroded for 10-15 minutes at a boundary shear stress of 4 Pa. Velocity profiles and distance to the soil surface were measured continuously using a profiling acoustic doppler velocimeter. Differences in

  11. Navy Water Conservation Guide for Shore Activities.

    Science.gov (United States)

    1996-07-01

    water overuse, abuse, and apa - tation of the principles of water con- thy. DOE estimates that water use servation at your Navy facility will in the...Sacramento, CA: 1994. Camacho, Norma , et. al. Water Conservation Technology Guide. NEESA-1 - 040. Naval Energy and Environmental Support Activity...Conservation Technology Document, Naval Civil Engineering Laboratory, page 7-8. Port Hueneme, CA: 1985. Figure 4-7: Camacho, Norma , et. al. NEESA 1-040

  12. Temperature Dependence of Mineral Solubility in Water. Part I. Alkaline and Alkaline Earth Chlorides

    Science.gov (United States)

    Krumgalz, B. S.

    2017-12-01

    A database of alkaline and alkaline earth chloride solubilities in water at various temperatures was created using data from more than 670 publications over about the last two centuries. Statistical critical evaluations of the created database were produced since there were enough independent data sources to justify such evaluations. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed minerals have been calculated at various temperature intervals and also represented by polynomial expressions. The solubility products calculated in the current study yield excellent agreement between the predicted and experimental mineral solubility values in natural waters over a wide range of temperature and ionic solution matrices.

  13. Water Vapor Sorption Properties of Polyethylene Terephthalate over a Wide Range of Humidity and Temperature.

    Science.gov (United States)

    Dubelley, Florence; Planes, Emilie; Bas, Corine; Pons, Emmanuelle; Yrieix, Bernard; Flandin, Lionel

    2017-03-02

    The dynamic and equilibrium water vapor sorption properties of amorphous polyethylene terephthalate were determined via gravimetric analysis over a wide range of temperatures (23-70 °C) and humidities (0-90% RH). At low temperature and relative humidity, the dynamics of the sorption process was Fickian. Increasing the temperature or relative humidity induced a distinct up-swing effect, which was associated with a plasticization/clustering phenomenon. For high temperatures and relative humidity, a densification of the polymer was evidenced. In addition to the classical Fickian diffusion, a new parameter was introduced to express the structural modifications of PET. Finally, two partial pressures were defined as thresholds that control the transition between these three phases. A simplified state diagram was finally proposed. In addition, the thermal dependence of these sorption modes was also determined and reported. The enthalpy of Henry's water sorption and the activation energy of diffusion were independent of vapor pressure and followed an Arrhenius law.

  14. The influence of temperature on corn seed water uptake

    Directory of Open Access Journals (Sweden)

    Lekić Slavoljub S.

    2000-01-01

    Full Text Available Temperature is a very important factor which effects seed water uptake. In this paper we investigated the effect of high temperature and high humidity on seed rate imbibition for five corn hybrids. Seeds were placed at the temperature of 41°C and 95-100% relative humidity (treatment . These seeds were compared with control. Seeds were hydrated at 12°C and 20°C for 6, 12, 24, 48 h. The highest imbibition rate was shown by ZP SC 599 hydride seed. The lowest imbibition rate was shown by ZP SC 599 hybrid seed. The seed treated at 12°C had the lowest imbibition rate. At 20°C differences in imbibition rate were lower than at 12°C. .

  15. Assessment of Water Ingress Accidents in a Modular High-Temperature Gas-Cooled Reactor

    OpenAIRE

    Zhang, Z.; Dong, Y; Scherer, W

    2005-01-01

    Severe water ingress accidents in the 200-MW HTR-module were assessed to determine the safety margins of modular pebble-bed high-temperature gas-cooled reactors (HTR-module). The 200-MW HTR-module was designed by Siemens under the criteria that no active safety protection systems were necessary because of its inherent safe nature. For simulating the behavior of the HTR-module during severe water ingress accidents, a water, steam, and helium multiphase cavity model was developed and implemente...

  16. [Calculating method for crop water requirement based on air temperature].

    Science.gov (United States)

    Tao, Guo-Tong; Wang, Jing-Lei; Nan, Ji-Qin; Gao, Yang; Chen, Zhi-Fang; Song, Ni

    2014-07-01

    The importance of accurately estimating crop water requirement for irrigation forecast and agricultural water management has been widely recognized. Although it has been broadly adopted to determine crop evapotranspiration (ETc) via meteorological data and crop coefficient, most of the data in whether forecast are qualitative rather than quantitative except air temperature. Therefore, in this study, how to estimate ETc precisely only using air temperature data in forecast was explored, the accuracy of estimation based on different time scales was also investigated, which was believed to be beneficial to local irrigation forecast as well as optimal management of water and soil resources. Three parameters of Hargreaves equation and two parameters of McClound equation were corrected by using meteorological data of Xinxiang from 1970 to 2010, and Hargreaves equation was selected to calculate reference evapotranspiration (ET0) during the growth period of winter wheat. A model of calculating crop water requirement was developed to predict ETc at time scales of 1, 3, and 7 d intervals through combining Hargreaves equation and crop coefficient model based on air temperature. Results showed that the correlation coefficients between measured and predicted values of ETc reached 0.883 (1 d), 0.933 (3 d), and 0.959 (7 d), respectively. The consistency indexes were 0.94, 0.95 and 0.97, respectively, which showed that forecast error decreased with the increasing time scales. Forecasted accuracy with an error less than 1 mm x d(-1) was more than 80%, and that less than 2 mm x d(-1) was greater than 90%. This study provided sound basis for irrigation forecast and agricultural management in irrigated areas since the forecasted accuracy at each time scale was relatively high.

  17. Optimization of cosmetic preservation: water activity reduction.

    Science.gov (United States)

    Kerdudo, A; Fontaine-Vive, F; Dingas, A; Faure, C; Fernandez, X

    2015-02-01

    Preservation of cosmetics is a prerequisite for industrialization, and among the proposed solutions, self-preserved cosmetics are of great interest. One key influencing parameter in self-preservation is water activity; its reduction can help to fight against microbial growth in cosmetic products. This work presents a study on the influence of humectants on water activity and its consequence on the preservation of cosmetic formulations. First, water-humectants mixtures were considered. The influence of glycol and glycerin content, glycol chemical structure, glycerin purity and formulation process on the water activity of the binary mixture was studied. Molecular modelling was performed for a better understanding of the impact of glycol chemistry. Then, the results were applied to five different cosmetic formulations to get optimized products. Challenge test on five strains was carried out in that sense. We showed that the higher the humectants concentration, the lower the water activity. Glycol chemical structure also influenced water activity: propan-1,2-diol was more efficient than propan-1,3-diol, certainly because of a better stabilization in water of propan-1,2-diol as shown by DFT calculation. A drop by drop introduction of glycol in water favoured aw reduction. The best water activity loss was 6.6% and was reached on the cream formulation whose preservation was improved as evidenced by challenge test. Fabrication process as well as humectants concentration were shown to influence water activity. The hydroxyl group positions as well as the presence of an alkyl group on the glycol carbon chain impacted water binding as suggested by DFT calculation. Reducing aw improved the preservation of a cosmetic cream, inhibiting or slowing down the growth of bacteria and fungi. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  18. Low-temperature MTBE biodegradation in aquifer sediments with a history of low, seasonal ground water temperatures

    Science.gov (United States)

    Bradley, P.M.; Landmeyer, J.E.

    2006-01-01

    Sediments from two shallow, methyl tert-butyl ether (MTBE)-contaminated aquifers, with mean ground water temperatures ???10??C, demonstrated significant mineralization of [U-14C] MTBE to 14CO 2 at incubation temperatures as low as 4??C. These results indicate that microbial degradation can continue to contribute to the attenuation of MTBE in ground water under wintertime, low-temperature conditions. ?? 2006 National Ground Water Association.

  19. Low-Temperature Microbial Activity in River Systems

    National Research Council Canada - National Science Library

    White, K

    2001-01-01

    This technical note examines dissolved oxygen (DO) levels and changes in river microbiology during winter, low temperatures, and periods of ice cover with the objective of providing guidance for winter water quality modeling...

  20. Immunomodulatory effects of temperature and pH of water in an Indian freshwater sponge.

    Science.gov (United States)

    Mukherjee, Soumalya; Bhunia, Anindya Sundar; Bhunia, Niladri Sekhar; Ray, Mitali; Ray, Sajal

    2016-07-01

    Eunapius carteri, a freshwater sponge of India, inhabits the ponds and lakes and experiences variations of temperature and pH of water throughout the year. Sponges bear evolutionary and ecological importance with limited information on their immunological attribute and adaptational resilience in a changing environment. This paper reports temperature and pH specific responses of immune related parameters in sponge maintained in the experimental conditions of laboratory. Innate immunological parameters like phagocytosis and generation of cytotoxic molecules like superoxide anion, nitric oxide and phenoloxidase activity were estimated in E. carteri at different environmentally realistic water temperatures (10, 20, 30 and 40°C) and pH (6.4, 7.4 and 8.4). Phagocytosis and cytotoxicity are established as important immune parameters of invertebrates. Calalase, an antioxidant enzyme and phosphatases are involved in pathogen destruction and are considered as components of innate immunity. Activities of catalase, acid and alkaline phosphatases were estimated in E. carteri at different thermal regimes and pH. Modulation of phagocytic and cytotoxic responses and the activities of catalase and phosphatases at different water temperatures and pH indicated temperature and pH specific immunological status of E. carteri. Present investigation deals with the effects of selected hydrological parameters on the fundamental immune related parameters in sponge indicating its adaptational plasticity. Immunological resilience of this species in the face of variation of water temperature and pH is thought to be a special adaptive feature of sponge, a reported "living fossil". Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. An operational analysis of Lake Surface Water Temperature

    Directory of Open Access Journals (Sweden)

    Emma K. Fiedler

    2014-07-01

    Full Text Available Operational analyses of Lake Surface Water Temperature (LSWT have many potential uses including improvement of numerical weather prediction (NWP models on regional scales. In November 2011, LSWT was included in the Met Office Operational Sea Surface Temperature and Ice Analysis (OSTIA product, for 248 lakes globally. The OSTIA analysis procedure, which has been optimised for oceans, has also been used for the lakes in this first version of the product. Infra-red satellite observations of lakes and in situ measurements are assimilated. The satellite observations are based on retrievals optimised for Sea Surface Temperature (SST which, although they may introduce inaccuracies into the LSWT data, are currently the only near-real-time information available. The LSWT analysis has a global root mean square difference of 1.31 K and a mean difference of 0.65 K (including a cool skin effect of 0.2 K compared to independent data from the ESA ARC-Lake project for a 3-month period (June to August 2009. It is demonstrated that the OSTIA LSWT is an improvement over the use of climatology to capture the day-to-day variation in global lake surface temperatures.

  2. Development of solid electrolytes for water electrolysis at higher temperature

    Energy Technology Data Exchange (ETDEWEB)

    Linkous, C.A. [Florida Solar Energy Center, Cocoa, FL (United States)

    1996-10-01

    This report describes efforts in developing new solid polymer electrolytes that will enable operation of proton exchange membrane electrolyzers at higher temperatures than are currently possible. Several ionomers have been prepared from polyetheretherketone (PEEK), polyethersulfone (PES), and polyphenylquinoxaline (PPQ) by employing various sulfonation procedures. By controlling the extent of sulfonation, a range of proton conductivities could be achieved, whose upper limit actually exceeded that of commercially available perfluoralkyl sulfonates. Thermoconductimetric analysis of samples at various degrees of sulfonation showed an inverse relationship between conductivity and maximum operating temperature. This was attributed to the dual effect of adding sulfonate groups to the polymer: more acid groups produce more protons for increased conductivity, but they also increase water uptake, which mechanically weakens the membrane. This situation was exacerbated by the limited acidity of the aromatic sulfonic acids (pK{sub A} {approx} 2-3). The possibility of using partial fluorination to raise the acid dissociation constant is discussed.

  3. Proxy comparisons for Paleogene sea water temperature reconstructions

    Science.gov (United States)

    de Bar, Marijke; de Nooijer, Lennart; Schouten, Stefan; Ziegler, Martin; Sluijs, Appy; Reichart, Gert-Jan

    2017-04-01

    Several studies have reconstructed Paleogene seawater temperatures, using single- or multi-proxy approaches (e.g. Hollis et al., 2012 and references therein), particularly comparing TEX86 with foraminiferal δ18O and Mg/Ca. Whereas trends often agree relatively well, absolute temperatures can differ significantly between proxies, possibly because they are often applied to (extreme) climate events/transitions (e.g. Sluijs et al., 2011), where certain assumptions underlying the temperature proxies may not hold true. A more general long-term multi-proxy temperature reconstruction, is therefore necessary to validate the different proxies and underlying presumed boundary conditions. Here we apply a multi-proxy approach using foraminiferal calcite and organic proxies to generate a low-resolution, long term (80 Myr) paleotemperature record for the Bass River core (New Jersey, North Atlantic). Oxygen (δ18O), clumped isotopes (Δ47) and Mg/Ca of benthic foraminifera, as well as the organic proxies MBT'-CBT, TEX86H, U37K' index and the LDI were determined on the same sediments. The youngest samples of Miocene age are characterized by a high BIT index (>0.8) and fractional abundance of the C32 1,15-diol (>0.6; de Bar et al., 2016) and the absence of foraminifera, all suggesting high continental input and shallow depths. The older sediment layers (˜30 to 90 Ma) display BIT values and C32 1,15-diol fractional abundances global transition from the Cretaceous to Eocene greenhouse world into the icehouse climate. The TEX86H sea surface temperature (SST) record shows a gradual cooling over time of ˜35 to 20 ˚ C, whereas the δ18O-derived bottom water temperatures (BWTs) decrease from ˜20 to 10 ˚ C, and the Mg/Ca and Δ47-derived BWTs decrease from ˜25 to 15 ˚ C. The absolute temperature difference between the δ18O and Δ47, might be explained by local variations in seawater δ18O composition. Similarly, the difference in Mg/Ca- and δ18O-derived BWTs is likely caused by

  4. Monitoring changes in skin temperature associated with exercise in horses on a water treadmill by use of infrared thermography.

    Science.gov (United States)

    Yarnell, Kelly; Fleming, Jennifer; Stratton, Tim D; Brassington, Rebecca

    2014-10-01

    Infrared thermography (IRT) was used to assess surface temperature change as an indirect measure of muscle activity and exercise associated changes in blood flow in the working hind limb muscles of horses (n=7) undergoing water treadmill exercise. Three treatments were investigated including the treadmill ran dry (TD), water at the height of the proximal interphalangeal joint (PIP) and water at the height of the carpus (CP). Maximum skin surface temperature was recorded from the region of the semitendinosus muscle during exercise at each water height. There was a significant difference in surface hind limb temperature between exercise on the water treadmill ran dry and with water at the height of the PIP and CP (P<0.0001) with hotter temperatures recorded during the TD treatment. There was a greater increase in surface temperature of the hind limbs from pre exercise to maximum temperature during the PIP and CP treatments when compared to the TD treatment, however, this was not significant (P=0.58). There was no significant difference in surface hind limb temperature found between exercise in water at the height of the PIP and water at the height of the CP. The findings from this study suggest that IRT is able to non-invasively detect muscle activity and associated changes in blood flow whilst horses are exercised on a water treadmill. IRT could potentially be used as an alternative method to assess muscle activity and temperature change in an aquatic environment where existing methods present methodological challenges. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Geothermic analysis of high temperature hydrothermal activities area in Western plateau of Sichuan province, China

    Science.gov (United States)

    Zhang, J.

    2016-12-01

    There is a high temperature hydrothermal activity area in the western plateau of Sichuan. More than 200 hot springs points have been found in the region, including 11 hot spring water temperature above local boiling point. Most of these distribute along Jinshajjiang fracture, Dege-Xiangcheng fracture, Ganzi-Litang fracture as well as Xianshuihe fracture, and form three high-temperature hydrothermal activity strips in the NW-SE direction. Using gravity, magnetic, seismic and helium isotope data, this paper analyzed the crust-mantle heat flow structure, crustal heat source distribution and water heating system. The results show that the geothermal activity mainly controlled by the "hot" crust. The ratio of crustal heat flow and surface heat flow is higher than 60%. In the high temperature hydrothermal activities area, there is lower S wave velocity zone with VsGeothermal water mainly reserve in the Triassic strata of the containing water good carbonate rocks, and in the intrusive granite which is along the fault zone. The thermal energy of Surface heat thermal activities mainly comes from the high-temperature hot source which is located in the middle and lower crust. Being in the deep crustal fracture, the groundwater infiltrated to the deep crust and absorbed heat, then, quickly got back to the surface and formed high hot springs.

  6. Arachidonic Acid and Eicosapentaenoic Acid Metabolism in Juvenile Atlantic Salmon as Affected by Water Temperature.

    Directory of Open Access Journals (Sweden)

    Fernando Norambuena

    Full Text Available Salmons raised in aquaculture farms around the world are increasingly subjected to sub-optimal environmental conditions, such as high water temperatures during summer seasons. Aerobic scope increases and lipid metabolism changes are known plasticity responses of fish for a better acclimation to high water temperature. The present study aimed at investigating the effect of high water temperature on the regulation of fatty acid metabolism in juvenile Atlantic salmon fed different dietary ARA/EPA ratios (arachidonic acid, 20:4n-6/ eicosapentaenoic acid, 20:5n-3, with particular focus on apparent in vivo enzyme activities and gene expression of lipid metabolism pathways. Three experimental diets were formulated to be identical, except for the ratio EPA/ARA, and fed to triplicate groups of Atlantic salmon (Salmo salar kept either at 10°C or 20°C. Results showed that fatty acid metabolic utilisation, and likely also their dietary requirements for optimal performance, can be affected by changes in their relative levels and by environmental temperature in Atlantic salmon. Thus, the increase in temperature, independently from dietary treatment, had a significant effect on the β-oxidation of a fatty acid including EPA, as observed by the apparent in vivo enzyme activity and mRNA expression of pparα -transcription factor in lipid metabolism, including β-oxidation genes- and cpt1 -key enzyme responsible for the movement of LC-PUFA from the cytosol into the mitochondria for β-oxidation-, were both increased at the higher water temperature. An interesting interaction was observed in the transcription and in vivo enzyme activity of Δ5fad-time-limiting enzyme in the biosynthesis pathway of EPA and ARA. Such, at lower temperature, the highest mRNA expression and enzyme activity was recorded in fish with limited supply of dietary EPA, whereas at higher temperature these were recorded in fish with limited ARA supply. In consideration that fish at higher

  7. Temperature dependence of the calibration factor of radon and radium determination in water samples by SSNTD

    CERN Document Server

    Hunyadi, I; Hakl, J; Baradacs, E; Dezso, Z

    1999-01-01

    The sensitivity of a sup 2 sup 2 sup 6 Ra determination method of water samples by SSNTD was measured as a function of storage temperature during exposure. The method is based on an etched track type radon monitor, which is closed into a gas permeable foil and is immersed in the water sample. The sample is sealed in a glass vessel and stored for an exposure time of 10-30 days. The sensitivity increased more than a factor of two when the storage temperature was raised from 2 deg. C to 30 deg. C. Temperature dependence of the partition coefficient of radon between water and air provides explanation for this dependence. For practical radio- analytical application the temperature dependence of the calibration factor is given by fitting the sensitivity data obtained by measuring sup 2 sup 2 sup 6 Ra standard solutions (in the activity concentration range of 0.1-48.5 kBq m sup - sup 3) at different storage temperatures.

  8. Monitoring and modeling water temperature and trophic status of a shallow Mediterranean lake

    Science.gov (United States)

    Giadrossich, Filippo; Bueche, Thomas; Pulina, Silvia; Marrosu, Roberto; Padedda, Bachisio Mario; Mariani, Maria Antonietta; Vetter, Mark; Cohen, Denis; Pirastru, Mario; Niedda, Marcello; Lugliè, Antonella

    2017-04-01

    Lakes are sensitive to changes in climate and human activities. Over the last few decades, Mediterranean lakes have experienced various problems due to the current climate change (drought, flood, warming, salt accumulation, water quality changes, etc.), often amplified by water use, intensification of land use activities, and pollution. The overall impact of these changes on water resources is still an open question. In this study we monitor the trophic status and the dynamics of water temperature of Lake Baratz, the only natural lake in Sardinia, Italy, characterized by high salinity and shallow depth. We extend the research carried out in the past 8 years by integrating new physical, chemical and biological data using a multidisciplinary approach that combines hydrological and biological dynamics. In particular, the lake water balance and the thermal and hydrochemical regime are studied with a lake dynamic model (the General Lake Model or GLM) which combine the energy budget method for estimating lake evaporation, and a physically-based rainfall-runoff simulator for estimating lake inflow, calibrated with measurements at the cross section of the main inlet stream. The trophic state of the lake was evaluated applying the OCDE Probability Distribution Diagrams method, which requires nutrient concentrations in the lake (total phosphorus), phytoplankton chlorophyll a and Secchi disk transparency data. We collected field data from a raft station and a land station, measuring net solar radiation, air temperature and relative humidity, precipitation, wind velocity, atmospheric pressure, and temperature from thermistors submerged in the uppermost three centimeters of water and beneath the lake surface at depths of 1, 2, 3, 4, 5, 6, and 8 m. Samples for nutrients and chlorophyll a analyses were collected at the same above mentioned depths close to the raft station using a Niskin bottle. Temperature, salinity, pH, and dissolved oxygen were measured using a multi

  9. Research for Preseismic Phenomena on the Underground Water Level and Temperature in Selected Areas of Greece

    Science.gov (United States)

    Contadakis, M. E.; Asteriadis, G.

    1997-08-01

    A comprehensive study of the tectonic activity require the contribution of a variety of methods, geological, seismic, geodetic, satellite etc., being currently available in our days. On the other hand, the risk evaluation in areas of high seismicity, like this one of the South Balkan Peninsula, is of vital importance. To this purpose an interdisciplinary following up of the tectonic activity in the area may provide the best provision to the administration for an effective confrontation and intervention for the elimination of the possible disastrous effects in human life cost, financial and social cost of the communities, to which may result a strong earthquake. Among the various methods of indirect monitoring of the tectonic activity in an area, which in addition is of a low cost, is that of the following up of the underground water level and temperature changes in the area of interest. This method is based on the fact that tectonic activity is expected to result to tectonic stresses producing alterations to the local water table which in its turn is expected is expected to be observed as variation of the underground water level and temperature. The method of the following up of the underground water and temperature changes has been applied, among others by the Department of Geodesy and Surveying of the University of Thessaloniki in two areas of high seismicity in Greece: (a) The seismic zone of the lake Volvi in North Greece (40.5 deg N and 23.5 deg E) for ten years (1983-1992) and (b) the area of South Thessaly (39.2 deg N and 21 deg E) for three years (1994-1996). The statistical analysis of the observations, shows that the low frequency constituent (Sa,Ssa,Mf,Mm) of the earth tides and the barometric pressure have a small influence on the water level measurements. The shallow underground water network of South Thessaly is more sensitive to the non tectonic factors than the network of Volvi. Tentative correlation of the underground wat! er and temperature

  10. Effect of water electrolysis temperature of hydrogen production system using direct coupling photovoltaic and water electrolyzer

    Directory of Open Access Journals (Sweden)

    Tetsuhiko Maeda

    2016-01-01

    Full Text Available We propose control methods of a photovoltaic (PV-water electrolyzer (ELY system that generates hydrogen by controlling the number of ELY cells. The advantage of this direct coupling between PV and ELY is that the power loss of DC/DC converter is avoided. In this study, a total of 15 ELY cells are used. In the previous researches, the electrolyzer temperature was constantly controlled with a thermostat. Actually, the electrolyzer temperature is decided by the balance of the electrolysis loss and the heat loss to the outside. Here, the method to control the number of ELY cells was investigated. Maximum Power Point Tracking efficiency of more than 96% was achieved without ELY temperature control. Furthermore we construct a numerical model taking into account of ELY temperature. Using this model, we performed a numerical simulation of 1-year. Experimental data and the simulation results shows the validity of the proposed control method.

  11. Photocatalytic CO2 Activation by Water

    NARCIS (Netherlands)

    Yang, Chieh-Chao

    2011-01-01

    Photocatalytic activation of CO2 and water has potential for producing fuels by conversion of photon energy. However, the low productivity still limits practical application. In this study, the goal was to gain more fundamental insight in CO2 activation, and to provide guidelines for rational design

  12. Optimization to Low Temperature Activity in Psychrophilic Enzymes

    Directory of Open Access Journals (Sweden)

    Caroline Struvay

    2012-09-01

    Full Text Available Psychrophiles, i.e., organisms thriving permanently at near-zero temperatures, synthesize cold-active enzymes to sustain their cell cycle. These enzymes are already used in many biotechnological applications requiring high activity at mild temperatures or fast heat-inactivation rate. Most psychrophilic enzymes optimize a high activity at low temperature at the expense of substrate affinity, therefore reducing the free energy barrier of the transition state. Furthermore, a weak temperature dependence of activity ensures moderate reduction of the catalytic activity in the cold. In these naturally evolved enzymes, the optimization to low temperature activity is reached via destabilization of the structures bearing the active site or by destabilization of the whole molecule. This involves a reduction in the number and strength of all types of weak interactions or the disappearance of stability factors, resulting in improved dynamics of active site residues in the cold. Considering the subtle structural adjustments required for low temperature activity, directed evolution appears to be the most suitable methodology to engineer cold activity in biological catalysts.

  13. [Antibacterial activity of water soluble fraction from Scolopendra subspinipes mutilans].

    Science.gov (United States)

    Ren, Wen-hua; Zhang, Shuang-quan; Song, Da-xiang; Zhou, Kai-ya

    2007-01-01

    The water soluble fraction (SWSF) of centipede Scolopendra subspinipes mautilans, injected with Escherichia coli K12 D31 for 3-4 days showed broad-spectrum antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. It showed strong antibacterial activity against E. coli K12D31 at different temperatures, pH and ionic strengths. It did not show any hemolytic and agglutination activities at the concentration below 600 microg/ml. After E. coli K12 D31 treated with SWSF, the ultrastructure showed that its outer cell wall was broken, surface collapsed and intracellular substances leaked out.

  14. Coupled daily streamflow and water temperature modelling in large river basins

    NARCIS (Netherlands)

    Vliet, van M.T.H.; Yearsley, J.R.; Franssen, W.H.P.; Ludwig, F.; Haddeland, I.; Kabat, P.

    2012-01-01

    Realistic estimates of daily streamflow and water temperature are required for effective management of water resources (e.g. for electricity and drinking water production) and freshwater ecosystems. Although hydrological and process-based water temperature modelling approaches have been successfully

  15. Water temperatures and aquatic life. EEI publication No. 65-901

    Energy Technology Data Exchange (ETDEWEB)

    Wurtz, C.B.; Renn, C.E.

    1965-06-01

    This manual is a reference and guide for engineers, managers, administrators, and others responsible for maintaining favorable water quality as part of industrial operations. It is designed to examine effects of changes in water temperature upon fish life and upon small bottom-living organisms that are important in the food economy of fish. The abstracted information is divided into the following categories: effects of exposure; compound stress effects; effects on feeding and growth; effects on reproduction and development; effects on movement and activity; and environmental conditions. (HLW)

  16. THERMOPHYSICAL PROPERTIES AND WATER ACTIVITY OF TRANSFERRED CHEESE (UF

    Directory of Open Access Journals (Sweden)

    Mohsen Dalvi Esfahan

    2015-06-01

    Full Text Available Few data are available on the thermophysical properties of cheese in the ripening process.The main objective of this work was to investigate the effects of brining and temperature on the thermophysical properties, i.e., thermal conductivity, specific heat, density and water activity of UF cheese and finally we measure surface heat transfer coefficient .Then we develop models for thermophysical properties based on physical and multiple regression concept .

  17. Hot water epilepsy: seizure type, water temperature, EEG findings and treatment.

    Science.gov (United States)

    Zeki, Gokcil; Gokcil, Zeki; Ilker, Ipekdal Huseyin; Ipekdal, Huseyin Ilker; Hidir, Ulas Umit; Ulas, Umit Hidir; Zeki, Odabasi; Odabasi, Zeki

    2010-03-01

    Hot water epilepsy (HWE) or bathing epilepsy is one of the reflex epilepsies induced by hot water pouring over the head, face, neck, or trunk during bathing. The aim of this study was to demonstrate the clinical and electroencephalographic features and the management alternatives of the patients with HWE. The age of seizure onset, duration of seizure, family history, interictal and postictal electroencephalography findings, triggering temperature of water, type of seizure, medication, and follow-up results were evaluated for each patient. The mean age at seizure onset was 10.5 years. The mean duration of seizures was 10 years. Interictal EEG recordings showed focal abnormalities in 4 patients and generalized abnormalities in 3 patients. Only one patient had normal interictal EEG findings. Among the 8 patients with HWE, 6 had seizures only during hot bathing, whereas 2 had additional seizures. Seven patients had generalized tonic-clonic seizures and 1 patient had complex partial seizure during their hot bathings. The mean triggering temperature of water was calculated as 41.4 degrees C. The mean duration of follow-up period was 23 months. Five patients became seizure-free during the follow-up period and seizures persisted in 3 patients. Antiepileptic drugs were given (800 mg/d carbamazepine for 2 patients and 600 mg/d phenytoin for 1 patient) to these 3 patients and they also became seizure-free during the follow-up period. Hot water epilepsy is a benign reflex epilepsy. Lowering water temperature must be the first step for the treatment. If needed, antiepileptic drugs should be considered as an additive treatment.

  18. Record-high specific conductance and water temperature in San Francisco Bay during water year 2015

    Science.gov (United States)

    Work, Paul; Downing-Kunz, Maureen; Livsey, Daniel

    2017-02-22

    The San Francisco estuary is commonly defined to include San Francisco Bay (bay) and the adjacent Sacramento–San Joaquin River Delta (delta). The U.S. Geological Survey (USGS) has operated a high-frequency (15-minute sampling interval) water-quality monitoring network in San Francisco Bay since the late 1980s (Buchanan and others, 2014). This network includes 19 stations at which sustained measurements have been made in the bay; currently, 8 stations are in operation (fig. 1). All eight stations are equipped with specific conductance (which can be related to salinity) and water-temperature sensors. Water quality in the bay constantly changes as ocean tides force seawater in and out of the bay, and river inflows—the most significant coming from the delta—vary on time scales ranging from those associated with storms to multiyear droughts. This monitoring network was designed to observe and characterize some of these changes in the bay across space and over time. The data demonstrate a high degree of variability in both specific conductance and temperature at time scales from tidal to annual and also reveal longer-term changes that are likely to influence overall environmental health in the bay.In water year (WY) 2015 (October 1, 2014, through September 30, 2015), as in the preceding water year (Downing-Kunz and others, 2015), the high-frequency measurements revealed record-high values of specific conductance and water temperature at several stations during a period of reduced freshwater inflow from the delta and other tributaries because of persistent, severe drought conditions in California. This report briefly summarizes observations for WY 2015 and compares them to previous years that had different levels of freshwater inflow.

  19. Electrochemical noise measurements of stainless steel in high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Arganis-Juarez, C.R. [Instituto Nacional de Investigaciones Nucleares Km. 36.5, Carretera Federal Mexico-Toluca, Municipio de Ocoyoacac, C.P. 52045, Estado de Mexico (Mexico); Malo, J.M. [Instituto de Investigaciones Electricas Av. Reforma 113, Col. Palmira, C.P. 62490, Cuernavaca, Morelos (Mexico)], E-mail: jmmalo@iie.org.mx; Uruchurtu, J. [Centro de Investigaciones en Ingenieria y Ciencias Aplicadas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C.P. 62210, Cuernavaca, Morelos (Mexico)

    2007-12-15

    Corrosion in a high purity aqueous environment simulating a boiling water reactor (BWR) is addressed in this work. This condition necessitates autoclave experiments under high pressure and temperature. Long-term electrochemical noise measurements were explored as a mean to detect and monitor stress corrosion cracking phenomenon. An experimental set up, designed to insulate the working electrode from external interference, made possible to detect and monitor stress corrosion cracking in slow strain rate tests for sensitized and solution annealed 304 stainless steel at 288 {sup o}C. Time-series analysis showed variations in the signature of the current density series due to transgranular stress corrosion cracking (TGSCC) and intergranular stress corrosion cracking (IGSCC)

  20. Corrosion behaviour of construction materials for high temperature water electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    2010-01-01

    Different types of corrosion resistant stainless steels, Ni-based alloys as well as titanium and tantalum were evaluated as a possible metallic bipolar plate and construction material with respect to corrosion resistance under simulated conditions corresponding to the conditions in high temperature...... proton exchange membrane (PEM) water electrolysers (HTPEMWE). All samples were exposed to anodic polarisation in 85% phosphoric acid electrolyte solution. Platinum and gold plates were tested for the valid comparison. Steady-state voltammetry was used in combination with scanning electron microscopy...... and energy-dispersive X-ray spectroscopy. Results show that stainless steels are the most inclined to corrosion under high anodic polarization. Among alloys, Ni-based showed the highest corrosion resistance under conditions, simulating HTPEMWE. In particular, Inconel625 is the most promising alloy...

  1. Environmental challenges of deep water activities

    Energy Technology Data Exchange (ETDEWEB)

    Sande, Arvid

    1998-12-01

    In this presentation there are discussed the experiences of petroleum industry, and the projects that have been conducted in connection with the planning and drilling of the first deep water wells in Norway. There are also presented views on where to put more effort in the years to come, so as to increase the knowledge of deep water areas. Attention is laid on exploration drilling as this is the only activity with environmental potential that will take place during the next five years or so. The challenges for future field developments in these water depths are briefly discussed. 7 refs.

  2. Hydrogen generation from low-temperature water-rock reactions

    Science.gov (United States)

    Mayhew, L. E.; Ellison, E. T.; McCollom, T. M.; Trainor, T. P.; Templeton, A. S.

    2013-06-01

    Hydrogen is commonly produced during the high-temperature hydration of mafic and ultramafic rocks, owing to the oxidation of reduced iron present in the minerals. Hydrothermal hydrogen is known to sustain microbial communities in submarine vent and terrestrial hot-spring systems. However, the rates and mechanisms of hydrogen generation below temperatures of 150°C are poorly constrained. As such, the existence and extent of hydrogen-fuelled ecosystems in subsurface terrestrial and oceanic aquifers has remained uncertain. Here, we report results from laboratory experiments in which we reacted ground ultramafic and mafic rocks and minerals--specifically peridotite, pyroxene, olivine and magnetite--with anoxic fluids at 55 and 100°C, and monitored hydrogen gas production. We used synchrotron-based micro-X-ray fluorescence and X-ray absorption near-edge structure spectroscopy to identify changes in the speciation of iron in the materials. We report a strong correlation between molecular hydrogen generation and the presence of spinel phases--oxide minerals with the general formula [M2+M23+]O4 and a cubic crystal structure--in the reactants. We also identify Fe(III)-(hydr)oxide reaction products localized on the surface of the spinel phases, indicative of iron oxidation. We propose that the transfer of electrons between Fe(II) and water adsorbed to the spinel surfaces promotes molecular hydrogen generation at low temperatures. We suggest that these localized sites of hydrogen generation in ultramafic aquifers in the oceanic and terrestrial crust could support hydrogen-based microbial life.

  3. Temperature effects on surface activity and application in oxidation ...

    Indian Academy of Sciences (India)

    Correspondingly, the CMC of CTAB-SDS decreases almost by half. The increase of surface activity of CTAB-SDS can be attributed to the relatively weak electrostatic interaction at high temperature, which is supported by the increase of solubility of CTAB-SDS with rise in temperature. Catalytic effect on oxidation of toluene ...

  4. Critical water activity and amorphous state for optimal preservation of lyophilised lactic acid bacteria

    OpenAIRE

    Passot, Stéphanie; Cenard, Stéphanie; Douania, Inès; Trelea, Ioan Cristian; Fonseca, Fernanda

    2012-01-01

    International audience; The aim of this study was to investigate the influence of the water activity on the stability of lyophilised lactic acid bacteria, especially in the solid glassy region. Lactobacillus bulgaricus CFL1 was co-lyophilised with sucrose and stored under controlled relative humidity at 25 °C. Glass transition temperature (T g), water activity, water content and loss of specific acidification activity during storage were determined. The rates of bacteria degradation were anal...

  5. Influence of temperature on daily locomotor activity in the crab Uca pugilator.

    Directory of Open Access Journals (Sweden)

    Audrey M Mat

    Full Text Available Animals living in the intertidal zone are exposed to prominent temperature changes. To cope with the energetic demands of environmental thermal challenges, ectotherms rely mainly on behavioral responses, which may change depending on the time of the day and seasonally. Here, we analyze how temperature shapes crabs' behavior at 2 different times of the year and show that a transition from constant cold (13.5°C to constant warm (17.5°C water temperature leads to increased locomotor activity levels throughout the day in fiddler crabs (Uca pugilator collected during the summer. In contrast, the same transition in environmental temperature leads to a decrease in the amplitude of the daily locomotor activity rhythm in crabs collected during the winter. In other words, colder temperatures during the cold season favor a more prominent diurnal behavior. We interpret this winter-summer difference in the response of daily locomotor activity to temperature changes within the framework of the circadian thermoenergetics hypothesis, which predicts that a less favorable energetic balance would promote a more diurnal activity pattern. During the winter, when the energetic balance is likely less favorable, crabs would save energy by being more active during the expected high-temperature phase of the day-light phase-and less during the expected low-temperature phase of the day-dark phase. Our results suggest that endogenous rhythms in intertidal ectotherms generate adaptive behavioral programs to cope with thermoregulatory demands of the intertidal habitat.

  6. Active layer thickness and ground temperatures, Svea, Svalbard, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — Snow and soil temperature records for January 1988 - May 1996 are presented. Included are snow depth and weight measurements, snow density (calculated), active layer...

  7. Studies of Water Absorption Behavior of Plant Fibers at Different Temperatures

    Science.gov (United States)

    Saikia, Dip

    2010-05-01

    Moisture absorption of natural fiber plastic composites is one major concern in their outdoor applications. The absorbed moisture has many detrimental effects on the mechanical performance of these composites. A knowledge of the moisture diffusivity, permeability, and solubility is very much essential for the application of natural fibers as an excellent reinforcement in polymers. An effort has been made to study the water absorption behavior of some natural fibers such as bowstring hemp, okra, and betel nut at different temperatures to improve the long-term performance of composites reinforced with these fibers. The gain in moisture content in the fibers due to water absorption was measured as a function of exposure time at temperatures ranging from 300 K to 340 K. The thermodynamic parameters of the sorption process, such as diffusion coefficients and corresponding activation energies, were estimated.

  8. Discharge, water temperature, and water quality of Warm Mineral Springs, Sarasota County, Florida: A retrospective analysis

    Science.gov (United States)

    Metz, Patricia A.

    2016-09-27

    in inland areas, and upward flow toward the surface in coastal areas, such as at Warm Mineral Springs. Warm Mineral Springs is located in a discharge area. Changes in water use in the region have affected the potentiometric surface of the Upper Floridan aquifer. Historical increase in groundwater withdrawals resulted in a 10- to 20-foot regional decline in the potentiometric surface of the Upper Floridan aquifer by May 1975 relative to predevelopment levels and remained at approximately that level in May 2007 in the area of Warm Mineral Springs. Discharge measurements at Warm Mineral Springs (1942–2014) decreased from about 11–12 cubic feet per second in the 1940s to about 6–9 cubic feet per second in the 1970s and remained at about that level for the remainder of the period of record. Similarity of changes in regional water use and discharge at Warm Mineral Springs indicates that basin-scale changes to the groundwater system have affected discharge at Warm Mineral Springs. Water temperature had no significant trend in temperature over the period of record, 1943–2015, and outliers were identified in the data that might indicate inconsistencies in measurement methods or locations.Within the regional groundwater basin, Warm Mineral Springs is influenced by deep Upper Floridan aquifer flow paths that discharge toward the coast. Associated with these flow paths, the groundwater temperatures increase with depth and toward the coast. Multiple lines of evidence indicate that a source of warm groundwater to Warm Mineral Springs is likely the permeable zone of the Avon Park Formation within the Upper Floridan aquifer at a depth of about 1,400 to 1,600 feet, or deeper sources. The permeable zone contains saline groundwater with water temperatures of at least 95 degrees Fahrenheit.The water quality of Warm Mineral Springs, when compared with other springs in Florida had the highest temperature and the greatest mineralized content. Warm Mineral Springs water is

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

    OpenAIRE

    Ricardo Mora-Rodriguez; Juan F. Ortega; Fernandez-Elias, Valentin E.; Maria Kapsokefalou; Olga Malisova; Adelais Athanasatou; Marlien Husemann; Kirsten Domnik; Hans Braun

    2016-01-01

    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 whi...

  10. Effect of Water Activity on the Free Fatty Acid Value of Crude Palm ...

    African Journals Online (AJOL)

    The influence of water activity, aw on the storage quality of palm oil was examined. Equal proportions of palm oil were put in three different water activity media for a period of 21 days at room temperature. A fourth sample representing the control was placed by the window in the laboratory. Aliquots were withdrawn at an ...

  11. Estimating Water Ice Abundance from Short-Wave Infrared Spectra of Drill Cuttings at Cryogenic Temperatures

    Science.gov (United States)

    Roush, Ted L.; Colaprete, Anthony; Kleinhenz, Julie; Cook, Amanda

    2017-01-01

    NASA's Resource Prospector (RP) mission intends to visit a lunar polar region to characterize the volatile distribution. Part of the RP payload, the Near-infrared Volatile Spectrometer System (NIRVSS) is a spectrometer operating from 1600-3400 nm that provides sensitivity to water ice, and other volatiles. For multiple years, the NIRVSS system has been incorporated into on-going RP payload testing in a cryogenic vacuum facility at Glenn Research Center. Soil tubes of lunar simulants, prepared with known amounts of water, are placed in the vacuum chamber and cooled to cryogenic temperatures (soil temperatures of 110-170 K) and placed under low vacuum (a few x 10(exp -6) Torr). During these tests NIRVSS continuously measures spectra of soil cuttings emplaced onto the surface by a drill. Real time processing of NIRVSS spectra produces two spectral parameters associated with water ice absorption features near 2000 and 3000 nm that can be used to inform decision making activities such as delivery of the soil to a sealable container. Post-test collection and analyses of the soils permit characterization the water content as a function of depth. These water content profiles exhibit the characteristics of a vacuum desiccation zone to depths of about 40 cm. Subsequent to completion of the tests, NIRVSS spectra are processed to produce two spectral parameters associated with water ice absorption features near 2000 and 3000 nm. These features can be evaluated as a function of time, and correlated with drill depth, and other measurements, throughout the drilling activities. Until now no effort was attempted to quantitatively relate these parameters to water abundance. This is the focus of our efforts to be presented.

  12. Measurement of water transfer and swelling stress in the buffer material due to temperature gradient

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, H. [ITC, Tokai, Ibaraki (Japan); Chijimatsu, M.; Fujita, A.

    1999-03-01

    Coefficients concerning the water transfer in the buffer material was obtained by empirically giving a temperature gradient, and the swelling stress was measured when water was soaked in the sample under the uniform temperature and temperature gradient conditions. The distributions of temperature and water in the buffer material empirically given a temperature gradient were measured to deduce water diffusion constant due to the temperature gradient. The diffusion constant was the order of 10{sup -8} cm{sup 2}/s/degC. As a result of a equitemperature soaking test, it was found that the swelling stress of the part where soaktion was slow was greater than that of the part with fast soaking at a stage of non-uniform water distribution. The water soaking quantity to the sample and swelling stress reached a stationary state after 7000 hours and the water distribution in the whole sample was found saturated. (H. Baba)

  13. Severe water ingress accident analysis for a Modular High Temperature Gas Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zuoyi [Inst. of Nuclear Energy Technology Tsinghua Univ., Beijing, BJ (China); Scherer, Winfried

    1997-12-31

    This paper analyzes the severe water ingress accidents in the SIEMENS 200MW Modular High Temperature Gas Cooled Reactor (HTR-Module) under the assumption of no active safety protection systems in order to find the safety margin of the current HTR-Module design. A water, steam and helium multi-phase cavity model is originally developed and implemented in the DSNP simulation system. The developed DSNP system is used to simulate the primary circuit of HTR-Module power plant. The comparisons of the models with the TINTE calculations validate the current simulation. After analyzing the effects of blower separation on water droplets, the wall heat storage, etc., it is found that the maximum H{sub 2}O density increase rate in the reactor core is smaller than 0.3 kg/(m{sup 3}s). The liquid water vaporization in the steam generator and H{sub 2}O transport from the steam generator to the reactor core reduces the impulse of the H{sub 2}O in the reactor core. The nuclear reactivity increase caused by the water ingress leads to a fast power excursion, which, however, is inherently counterbalanced by negative feedback effects. Concerning the integrity of the fuel elements, the safety relevant temperature limit of 1600degC was not reached in any case. (author)

  14. Germination of Winter Annual Grass Weeds under a Range of Temperatures and Water Potentials

    DEFF Research Database (Denmark)

    Scherner, Ananda; Melander, Bo; Jensen, Peter Kryger

    2017-01-01

    , and rattail fescue in multiple water potentials and temperature regimes. Temperature and water potential effects were similar between silky windgrass and rattail fescue, but differed from annual bluegrass. The three grass weeds were able to germinate under low water potential (−1.0 MPa), although water...... potentials ≤−0.25 MPa strongly delayed their germination. Silky windgrass and rattail fescue seeds were able to germinate at 1 C, while the minimum temperature for annual bluegrass germination was 5 C. Germination of silky windgrass and rattail fescue was very similar across temperature and water potentials...

  15. Thermal insulation and body temperature wearing a thermal swimsuit during water immersion.

    Science.gov (United States)

    Wakabayashi, Hitoshi; Hanai, Atsuko; Yokoyama, Shintaro; Nomura, Takeo

    2006-09-01

    This study evaluated the effects of a thermal swimsuit on body temperatures, thermoregulatory responses and thermal insulation during 60 min water immersion at rest. Ten healthy male subjects wearing either thermal swimsuits or normal swimsuits were immersed in water (26 degrees C or 29 degrees C). Esophageal temperature, skin temperatures and oxygen consumption were measured during the experiments. Metabolic heat production was calculated from oxygen consumption. Heat loss from skin to the water was calculated from the metabolic heat production and the change in mean body temperature during water immersion. Total insulation and tissue insulation were estimated by dividing the temperature difference between the esophagus and the water or the esophagus and the skin with heat loss from the skin. Esophageal temperature with a thermal swimsuit was higher than that with a normal swimsuit at the end of immersion in both water temperature conditions (pthermal swimsuit than with a normal swimsuit in both water temperatures (pinsulation with the thermal swimsuit was higher than that with a normal swimsuit due to insulation of the suit at both water temperatures (pinsulation was similar in all four conditions, but significantly higher with the thermal swimsuit in both water temperature conditions (pthermal swimsuit. A thermal swimsuit can increase total insulation and reduce heat loss from the skin. Therefore, subjects with thermal swimsuits can maintain higher body temperatures than with a normal swimsuit and reduce shivering thermo-genesis.

  16. Integration of Space Heating and Hot Water Supply in Low Temperature District Heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

    2014-01-01

    pipes, where the water is at the highest temperature. The heat loss may be lowered by decreasing the temperatures in the network for which reason low temperature networks are proposed as a low loss solution for future district heating. However, the heating demand of the consumers involve both domestic...... hot water and space heating. Space heating may be provided at low temperature in modern low energy buildings. Domestic hot water, however, needs to reach sufficient temperatures to avoid growth of legionella bacteria. If the network temperature is below the temperature demand, supplementary heating...... is required by the consumer. In the present paper we study conventional district heating at different temperature levels and compare the energy efficiency, the exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature...

  17. UNIQUAC activity coefficient model for the systems of 1-propanol + water and 2-propanol + water

    Directory of Open Access Journals (Sweden)

    Numuang, C.

    2005-12-01

    Full Text Available Predictions of vapor liquid equilibria and azeotrope conditions of binary systems of 1-propanol+ water and 2-propanol+water at 30, 60, and 100 kPa were conducted in this work. UNIQUAC activity coefficient and ideal gas models represented behavior of the systems in liquid phase and vapor phase respectively. Experimental data collected from the literature (Gobaldon et al., 1996 and Marzal et al., 1996 were used to calculate energy interaction parameters of the UNIQUAC activity coefficient model by non-linear regression method. The obtained parameters were not dependent on temperature and mole fraction; however, those parameters were dependent on pressure of the system. The mean absolute error of vapor mole fraction of alcohol and water were in the range 3.86-4.65% and 2.33-3.28% respectively for the binary system of 1-propanol +water. The mean absolute error of vapor mole fraction of alcohol and water were in the range 1.93-2.06% and 1.47-1.94% respectively for the binary system of 2-propanol+water. The thermodynamics consistency test proved that the UNIQUAC activity coefficient model was satisfied very well with Gibbs- Duhem equation.

  18. Complex interactions between temperature and relative humidity on water balance of adult tsetse (Glossinidae, Diptera: implications for climate change

    Directory of Open Access Journals (Sweden)

    Elsje eKleynhans

    2011-10-01

    Full Text Available Insect water balance plays an important role in determining energy budgets, activity patterns, survival and population dynamics and, hence, geographic distribution. Tsetse (Glossina spp. are important vectors of human and animal disease occupying a wide range of habitats in Africa and are notable for their desiccation resistance in xeric environments. Here, we measure water balance traits (water loss rate, body water content and body lipid content in adult flies across a range of temperature (20 – 30 °C and relative humidity (0 – 99 % combinations in four tsetse species from both xeric and mesic habitats. Water loss rates were significantly affected by measurement under different temperature and relative humidity combinations, while body water content, body lipid content and mass were less affected. Different effects of temperature and relative humidity within and among experimental conditions and species suggests cuticular permeability and saturation deficit are likely to be key factors in forecasting tsetse water balance responses to climate variability. These results provide support for mass–independent inter– and intra–specific variation in water loss rates and survival times. Therefore, water balance responses to variation in temperature and relative humidity are complex in Glossina, and this response varies within and among species, sub–groups and ecotypes in terms of both magnitude of effects and the direction of change. This complicates potential forecasting of tsetse distribution in the face of climate change.

  19. Water-, pH- and temperature relations of germination for the extreme xerophiles Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471)

    NARCIS (Netherlands)

    Stevenson, Andrew; Hamill, Philip G; Dijksterhuis, Jan; Hallsworth, John E

    2016-01-01

    Water activity, temperature and pH are determinants for biotic activity of cellular systems, biosphere function and, indeed, for all life processes. This study was carried out at high concentrations of glycerol, which concurrently reduces water activity and acts as a stress protectant, to

  20. Water-, pH- and temperature relations of germination for the extreme xerophiles Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471)

    NARCIS (Netherlands)

    Stevenson, Andrew; Hamill, Philip G; Dijksterhuis, Jan; Hallsworth, John E

    Water activity, temperature and pH are determinants for biotic activity of cellular systems, biosphere function and, indeed, for all life processes. This study was carried out at high concentrations of glycerol, which concurrently reduces water activity and acts as a stress protectant, to

  1. Preferential flows and soil moistures on a Benggang slope: Determined by the water and temperature co-monitoring

    Science.gov (United States)

    Tao, Yu; He, Yangbo; Duan, Xiaoqian; Zou, Ziqiang; Lin, Lirong; Chen, Jiazhou

    2017-10-01

    Soil preferential flow (PF) has important effects on rainfall infiltration, moisture distribution, and hydrological and ecological process; but it is very difficult to monitor and characterize on a slope. In this paper, soil water and soil temperature at 20, 40, 60, 80 cm depths in six positions were simultaneously monitored at high frequency to confirm the occurrence of PF at a typical Benggang slope underlain granite residual deposits, and to determine the interaction of soil moisture distribution and Benggang erosion. In the presence of PF, the soil temperature was first (half to one hour) governed by the rainwater temperature, then (more than one hour) governed by the upper soil temperature; in the absence of PF (only matrix flow, MF), the soil temperature was initially governed by the upper soil temperature, then by the rainwater temperature. The results confirmed the water replacement phenomenon in MF, thus it can be distinguished from PF by additional temperature monitoring. It indicates that high frequency moisture and temperature monitoring can determine the occurrence of PF and reveal the soil water movement. The distribution of soil water content and PF on the different positions of the slope showed that a higher frequency of PF resulted in a higher variation of average of water content. The frequency of PF at the lower position can be three times as that of the upper position, therefore, the variation coefficient of soil water content increased from 4.67% to 12.68% at the upper position to 8.18%-33.12% at the lower position, where the Benggang erosion (soil collapse) was more possible. The results suggest strong relationships between PF, soil water variation, and collapse activation near the Benggang wall.

  2. ACTIVATED CARBON FROM LIGNITE FOR WATER TREATMENT

    Energy Technology Data Exchange (ETDEWEB)

    Edwin S. Olson; Daniel J. Stepan

    2000-07-01

    High concentrations of humate in surface water result in the formation of excess amounts of chlorinated byproducts during disinfection treatment. These precursors can be removed in water treatment prior to disinfection using powdered activated carbon. In the interest of developing a more cost-effective method for removal of humates in surface water, a comparison of the activities of carbons prepared from North Dakota lignites with those of commercial carbons was conducted. Previous studies indicated that a commercial carbon prepared from Texas lignite (Darco HDB) was superior to those prepared from bituminous coals for water treatment. That the high alkali content of North Dakota lignites would result in favorable adsorptive properties for the very large humate molecules was hypothesized, owing to the formation of larger pores during activation. Since no standard humate test has been previously developed, initial adsorption testing was performed using smaller dye molecules with various types of ionic character. With the cationic dye, methylene blue, a carbon prepared from a high-sodium lignite (HSKRC) adsorbed more dye than the Darco HDB. The carbon from the low-sodium lignite was much inferior. With another cationic dye, malachite green, the Darco HDB was slightly better. With anionic dyes, methyl red and azocarmine-B, the results for the HSKRC and Darco HDB were comparable. A humate test was developed using Aldrich humic acid. The HSKRC and the Darco HDB gave equally high adsorption capacities for the humate (138 mg/g), consistent with the similarities observed in earlier tests. A carbon prepared from a high-sodium lignite from a different mine showed an outstanding improvement (201 mg/g). The carbons prepared from the low-sodium lignites from both mines showed poor adsorption capacities for humate. Adsorption isotherms were performed for the set of activated carbons in the humate system. These exhibited a complex behavior interpreted as resulting from two types

  3. Orientational dynamics of room temperature ionic liquid/water mixtures: water-induced structure.

    Science.gov (United States)

    Sturlaugson, Adam L; Fruchey, Kendall S; Fayer, Michael D

    2012-02-16

    Optical heterodyne detected optical Kerr effect (OHD-OKE) measurements on a series of 1-alkyl-3-methylimidazolium tetrafluoroborate room-temperature ionic liquids (RTILs) as a function of chain length and water concentration are presented. The pure RTIL reorientational dynamics are identical in form to those of other molecular liquids studied previously by OHD-OKE (two power laws followed by a single exponential decay at long times), but are much slower at room temperature. In contrast, the addition of water to the longer alkyl chain RTILs causes the emergence of a long time biexponential orientational anisotropy decay. Such distinctly biexponential decays have not been seen previously in OHD-OKE experiments on any type of liquid and are analyzed here using a wobbling-in-a-cone model. The slow component for the longer chain RTILs does not obey the Debye-Stokes-Einstein (DSE) equation across the range of solutions, and thus we attribute it to slow cation reorientational diffusion caused by a stiffening of cation alkyl tail-tail associations. The fast component of the decay is assigned to the motions (wobbling) of the tethered imidazolium head groups. The wobbling-in-a-cone analysis provides estimates of the range of angles sampled by the imidazolium head group prior to the long time scale complete orientational randomization. The heterogeneous dynamics and non-DSE behavior observed here should have a significant effect on reaction rates in RTIL/water cosolvent mixtures.

  4. An experimental study on the influence of water stagnation and temperature change on water quality in a full-scale domestic drinking water system

    OpenAIRE

    Zlatanović, L.; van der Hoek, J.P.; Vreeburg, J.H.G.

    2017-01-01

    The drinking water quality changes during the transport through distribution systems. Domestic drinking water systems (DDWSs), which include the plumbing between the water meter and consumer's taps, are the most critical points in which water quality may be affected. In distribution networks, the drinking water temperature and water residence time are regarded as indicators of the drinking water quality. This paper describes an experimental research on the influence of stagnation time and tem...

  5. MODIS/Aqua Temperature and Water Vapor Profiles 5-Min L2 Swath 5km - NRT

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-2 MODIS Temperature and Water Vapor Profile Product MYD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature...

  6. PV water pumping: NEOS Corporation recent PV water pumping activities

    Energy Technology Data Exchange (ETDEWEB)

    Lane, C.

    1995-11-01

    NEOS Corporation has been very active in PV-powered water pumping, particularly with respect to electric utilities. Most of the recent activity has been through the Photovoltaic Services Network (PSN). The PSN is an independent, not-for-profit organization comprised of all types of electric utilities: rural electric coops, public power districts, investor-owned utilities, and power marketing agencies. The PSN`s mission is to work pro-actively to promote utility involvement in PV through education and training. PV information is distributed by the PSN in three primary forms: (1) consultation with PSN technical service representatives: (2) literature generated by the PSN; and (3) literature published by other organizations. The PSN can also provide assistance to members in developing PV customer service programs. The PSN`s product support activities include consolidation of information on existing packaged PV systems and facilitation of the development of new PV product packages that meet utility-defined specifications for cost performance, and reliability. The PSN`s initial product support efforts will be focused on commercially available packaged PV systems for a variety of off-grid applications. In parallel with this effort, if no products exist that meet the PSN`s functional specifications, the PSN will initiate the second phase of product development support process by encouraging the development of new packaged systems. Through these services and product support activities, the PSN anticipates engaging all segments for the PV industry, thus providing benefits to PV systems suppliers as well as local PV service contractors.This paper describes field testing of pv power systems for water pumping.

  7. Dual temperature dual pressure water-hydrogen chemical exchange for water detritiation

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Takahiko, E-mail: t-sugiyama@nucl.nagoya-u.ac.jp [Faculty of Engineering, Nagoya University, Fro-cho 1, Chikusa-ku, Nagoya 464-8603 (Japan); Takada, Akito; Morita, Youhei [Faculty of Engineering, Nagoya University, Fro-cho 1, Chikusa-ku, Nagoya 464-8603 (Japan); Kotoh, Kenji [Graduate School of Engineering, Kyushu University, Moto-oka 744, Nishi-ku, Fukuoka 819-0395 (Japan); Munakata, Kenzo [Faculty of Engineering and Resource Science, Akita University, Tegata-gakuen-machi 1-1, Akita 010-8502 (Japan); Taguchi, Akira [Hydrogen Isotope Research Center, University of Toyama, Gofuku 3190, Toyama 930-8555 (Japan); Kawano, Takao; Tanaka, Masahiro; Akata, Naofumi [National Institute for Fusion Science, Oroshi-cho 322-6, Toki, Gifu 509-5292 (Japan)

    2015-10-15

    Experimental and analytical studies on hydrogen-tritium isotope separation by a dual temperature dual pressure catalytic exchange (DTDP-CE) with liquid phase chemical exchange columns were carried out in order to apply it to a part of the water detritiation system for DEMO fuel cycle. A prototype DTDP-CE apparatus was successfully operated and it was confirmed that tritium was separated by the apparatus as significantly distinguishable. A calculation code was developed based on the channeling stage model. The values of separation factors and the effects of some operating parameters were well predicted by the separative analyses with the code.

  8. A hierarchical bayesian model to quantify uncertainty of stream water temperature forecasts.

    Directory of Open Access Journals (Sweden)

    Guillaume Bal

    Full Text Available Providing generic and cost effective modelling approaches to reconstruct and forecast freshwater temperature using predictors as air temperature and water discharge is a prerequisite to understanding ecological processes underlying the impact of water temperature and of global warming on continental aquatic ecosystems. Using air temperature as a simple linear predictor of water temperature can lead to significant bias in forecasts as it does not disentangle seasonality and long term trends in the signal. Here, we develop an alternative approach based on hierarchical Bayesian statistical time series modelling of water temperature, air temperature and water discharge using seasonal sinusoidal periodic signals and time varying means and amplitudes. Fitting and forecasting performances of this approach are compared with that of simple linear regression between water and air temperatures using i an emotive simulated example, ii application to three French coastal streams with contrasting bio-geographical conditions and sizes. The time series modelling approach better fit data and does not exhibit forecasting bias in long term trends contrary to the linear regression. This new model also allows for more accurate forecasts of water temperature than linear regression together with a fair assessment of the uncertainty around forecasting. Warming of water temperature forecast by our hierarchical Bayesian model was slower and more uncertain than that expected with the classical regression approach. These new forecasts are in a form that is readily usable in further ecological analyses and will allow weighting of outcomes from different scenarios to manage climate change impacts on freshwater wildlife.

  9. A hierarchical bayesian model to quantify uncertainty of stream water temperature forecasts.

    Science.gov (United States)

    Bal, Guillaume; Rivot, Etienne; Baglinière, Jean-Luc; White, Jonathan; Prévost, Etienne

    2014-01-01

    Providing generic and cost effective modelling approaches to reconstruct and forecast freshwater temperature using predictors as air temperature and water discharge is a prerequisite to understanding ecological processes underlying the impact of water temperature and of global warming on continental aquatic ecosystems. Using air temperature as a simple linear predictor of water temperature can lead to significant bias in forecasts as it does not disentangle seasonality and long term trends in the signal. Here, we develop an alternative approach based on hierarchical Bayesian statistical time series modelling of water temperature, air temperature and water discharge using seasonal sinusoidal periodic signals and time varying means and amplitudes. Fitting and forecasting performances of this approach are compared with that of simple linear regression between water and air temperatures using i) an emotive simulated example, ii) application to three French coastal streams with contrasting bio-geographical conditions and sizes. The time series modelling approach better fit data and does not exhibit forecasting bias in long term trends contrary to the linear regression. This new model also allows for more accurate forecasts of water temperature than linear regression together with a fair assessment of the uncertainty around forecasting. Warming of water temperature forecast by our hierarchical Bayesian model was slower and more uncertain than that expected with the classical regression approach. These new forecasts are in a form that is readily usable in further ecological analyses and will allow weighting of outcomes from different scenarios to manage climate change impacts on freshwater wildlife.

  10. Increasing Water Temperature Triggers Dominance of Small Freshwater Plankton: e0140449

    National Research Council Canada - National Science Library

    Serena Rasconi; Andrea Gall; Katharina Winter; Martin J Kainz

    2015-01-01

    ...") of aquatic ecosystems. Using a multi-seasonal, low trophic state mesocosm experiment, we investigated how higher water temperature and brownification affect plankton community composition, phenology, and functioning...

  11. Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features

    National Research Council Canada - National Science Library

    Luoto, Tomi P; Nevalainen, Liisa

    2013-01-01

    .... We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses...

  12. Quantifying the impact of human activity on temperatures in Germany

    Science.gov (United States)

    Benz, Susanne A.; Bayer, Peter; Blum, Philipp

    2017-04-01

    Human activity directly influences ambient air, surface and groundwater temperatures. Alterations of surface cover and land use influence the ambient thermal regime causing spatial temperature anomalies, most commonly heat islands. These local temperature anomalies are primarily described within the bounds of large and densely populated urban settlements, where they form so-called urban heat islands (UHI). This study explores the anthropogenic impact not only for selected cities, but for the thermal regime on a countrywide scale, by analyzing mean annual temperature datasets in Germany in three different compartments: measured surface air temperature (SAT), measured groundwater temperature (GWT), and satellite-derived land surface temperature (LST). As a universal parameter to quantify anthropogenic heat anomalies, the anthropogenic heat intensity (AHI) is introduced. It is closely related to the urban heat island intensity, but determined for each pixel (for satellite-derived LST) or measurement point (for SAT and GWT) of a large, even global, dataset individually, regardless of land use and location. Hence, it provides the unique opportunity to a) compare the anthropogenic impact on temperatures in air, surface and subsurface, b) to find main instances of anthropogenic temperature anomalies within the study area, in this case Germany, and c) to study the impact of smaller settlements or industrial sites on temperatures. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1 km × 1 km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity; unlike land surface temperature

  13. Engineering water-tolerant core/shell upconversion nanoparticles for optical temperature sensing.

    Science.gov (United States)

    Alkahtani, Masfer H; Gomes, Carmen L; Hemmer, Philip R

    2017-07-01

    Luminescence thermometry is a promising approach using upconversion nanoparticles (UCNPs) with a nanoscale regime in biological tissues. UCNPs are superior to conventional fluorescent markers, benefiting from their autofluorescence suppression and deep imaging in tissues. However, they are still limited by poor water solubility and weak upconversion luminescence intensity, especially at a small particle size. Recently, YVO4:Er(+3),Yb(+3) nanoparticles have shown high efficiency upconversion (UC) luminescence in water at single-particle level and high contrast imaging in biological models. Typically, a 980-nm laser triggers the UC process in the UCNPs, which overlaps with maximum absorption of water molecules that are dominant in biological samples, resulting in biological tissues overheating and possible damaging. Interestingly, neodymium (Nd(+3)) possesses a large absorption cross section at the water low absorption band (808 nm), which can overcome overheating issues. In this Letter, we introduce Nd(+3) as a new near-infrared absorber and UC sensitizer into YVO4:Er(+3),Yb(+3) nanoparticles in a core/shell structure to ensure successive energy transfer between the new UC sensitizer (Nd(+3)) to the upconverting activator (Er(+3)). Finally, we synthesized water-tolerant YVO4:Er(+3),Yb(+3)@Nd(+3) core/shell nanoparticles (average size 20 nm) with strong UC luminescence at a biocompatible excitation wavelength for optical temperature sensing where overheating in water is minimized.

  14. Biological Ice Nucleation Activity in Cloud Water (Invited)

    Science.gov (United States)

    Delort, A.

    2013-12-01

    Ice nucleation active (INA) biological particles, in particular microorganisms, were studied in cloud water. Twelve cloud samples were collected over a period of 16 months from the puy de Dôme summit (1465 m, France) using sterile cloud droplet impactors. The samples were characterized through biological (cultures, cell counts) and physico-chemical measurements (pH, ion concentrations, carbon content...), and biological ice nuclei were investigated by droplet-freezing assays from -3°C to -13°C. The concentration of total INA particles within this temperature range typically varied from ~1 to ~100 per mL of cloud water; the concentrations of biological IN were several orders of magnitude higher than the values previously reported for precipitations. At -12°C, at least 76% of the IN were biological in origin, i.e. they were inactivated by heating at 95°C, and at temperatures above -8°C only biological material could induce ice. By culture, 44 Pseudomonas-like strains of bacteria were isolated from cloud water samples; 16% of them were found INA at the temperature of -8°C and they were identified as Pseudomonas syringae, Xanthomonas sp. and Pseudoxanthomonas sp.. Two strains induced freezing at as warm as -2°C, positioning them among the most active ice nucleators described so far. We estimated that, in average, 0.18% and more than 1%.of the bacterial cells present in clouds (~104 mL-1) are INA at the temperatures of -8°C and -12°C, respectively.

  15. Temperature rise during experimental light-activated bleaching.

    Science.gov (United States)

    Klaric, Eva; Rakic, Mario; Sever, Ivan; Tarle, Zrinka

    2015-02-01

    The purpose of this study was to evaluate the surface and intrapulpal temperatures after treatments with different bleaching gels subjected to different types of light activation. A K-type thermocouple and infrared thermometer were used to measure the temperature increase during the 15- or 30-min treatment period. Light-emitting diode with a center wavelength of 405 nm (LED405), organic light-emitting diode (OLED), and femtosecond laser were tested and compared to ZOOM2. The tooth surface was treated with five bleaching agents and Vaseline which served as a control.The generalized estimating equation (GEE) model was applied for testing the differences in temperature increase. The ZOOM2 light source led to the largest increase in mean pulpal and tooth surface temperatures of 21.1 and 22.8 °C, followed by focused femtosecond laser which increased the pulpal and surface temperatures by up to 15.7 and 16.8 °C. Treatments with unfocused femtosecond laser, LED405, and OLED induced significantly lower mean temperature increases (p temperature increases in the pulp chamber and at the tooth surface. Caution is advised when using these types of light activation, while LED405, OLED, and unfocused femtosecond laser could be safely used.

  16. Arrhenius temperature dependence of in vitro tissue plasminogen activator thrombolysis

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, George J [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Dhamija, Ashima [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Bavani, Nazli [Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Wagner, Kenneth R [Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States); Holland, Christy K [Department of Biomedical Engineering, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0769 (United States)

    2007-06-07

    Stroke is a devastating disease and a leading cause of death and disability. Currently, the only FDA approved therapy for acute ischemic stroke is the intravenous administration of the thrombolytic medication, recombinant tissue plasminogen activator (tPA). However, this treatment has many contraindications and can have dangerous side effects such as intra-cerebral hemorrhage. These treatment limitations have led to much interest in potential adjunctive therapies, such as therapeutic hypothermia (T {<=} 35 deg. C) and ultrasound enhanced thrombolysis. Such interest may lead to combining these therapies with tPA to treat stroke, however little is known about the effects of temperature on the thrombolytic efficacy of tPA. In this work, we measure the temperature dependence of the fractional clot mass loss {delta}m(T) resulting from tPA exposure in an in vitro human clot model. We find that the temperature dependence is well described by an Arrhenius temperature dependence with an effective activation energy E{sub eff} of 42.0 {+-} 0.9 kJ mole{sup -1}. E{sub eff} approximates the activation energy of the plasminogen-to-plasmin reaction of 48.9 kJ mole{sup -1}. A model to explain this temperature dependence is proposed. These results will be useful in predicting the effects of temperature in future lytic therapies.

  17. Calculation of water activation for the LHC

    Science.gov (United States)

    Vollaire, Joachim; Brugger, Markus; Forkel-Wirth, Doris; Roesler, Stefan; Vojtyla, Pavol

    2006-06-01

    The management of activated water in the Large Hadron Collider (LHC) at CERN is a key concern for radiation protection. For this reason, the induced radioactivity of the different water circuits is calculated using the Monte-Carlo (MC) code FLUKA. The results lead to the definition of procedures to be taken into account during the repair and maintenance of the machine, as well as to measures being necessary for a release of water into the environment. In order to assess the validity of the applied methods, a benchmark experiment was carried out at the CERN-EU High Energy Reference Field (CERF) facility, where a hadron beam (120 GeV) is impinging on a copper target. Four samples of water, as used at the LHC, and different in their chemical compositions, were irradiated near the copper target. In addition to the tritium activity measured with a liquid scintillation counter, the samples were also analyzed using gamma spectroscopy in order to determine the activity of the gamma emitting isotopes such as Be7 and Na24. While for the latter an excellent agreement between simulation and measurement was found, for the calculation of tritium a correction factor is derived to be applied for future LHC calculations in which the activity is calculated by direct scoring of produced nuclei. A simplified geometry representing the LHC Arc sections is then used to evaluate the different calculation methods with FLUKA. By comparing these methods and by taking into account the benchmark results, a strategy for the environmental calculations can be defined.

  18. Cooling Effect of Water Injection on a High-Temperature Supersonic Jet

    Directory of Open Access Journals (Sweden)

    Jing Li

    2015-11-01

    Full Text Available The high temperature and high pressure supersonic jet is one of the key problems in the design of solid rocket motors. To reduce the jet temperature and noise, cooling water is typically injected into the exhaust plume. Numerical simulations for the gas-liquid multiphase flow field with mixture multiphase model were developed and a series of experiments were carried out. By introducing the energy source terms caused by the vaporization of liquid water into the energy equation, a coupling solution was developed to calculate the multiphase flow field. The temperature data predictions agreed well with the experimental results. When water was injected into the plume, the high temperature core region area was reduced, and the temperature on the head face was much lower than that without water. The relationship between the reduction of temperature on the bottom plate and the momentum ratio is developed, which can be used to predict the cooling effect of water injection in many cases.

  19. Improved AIOMFAC model parameterisation of the temperature dependence of activity coefficients for aqueous organic mixtures

    Science.gov (United States)

    Ganbavale, G.; Zuend, A.; Marcolli, C.; Peter, T.

    2015-01-01

    This study presents a new, improved parameterisation of the temperature dependence of activity coefficients in the AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) model applicable for aqueous as well as water-free organic solutions. For electrolyte-free organic and organic-water mixtures the AIOMFAC model uses a group-contribution approach based on UNIFAC (UNIversal quasi-chemical Functional-group Activity Coefficients). This group-contribution approach explicitly accounts for interactions among organic functional groups and between organic functional groups and water. The previous AIOMFAC version uses a simple parameterisation of the temperature dependence of activity coefficients, aimed to be applicable in the temperature range from ~ 275 to ~ 400 K. With the goal to improve the description of a wide variety of organic compounds found in atmospheric aerosols, we extend the AIOMFAC parameterisation for the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon to atmospherically relevant low temperatures. To this end we introduce a new parameterisation for the temperature dependence. The improved temperature dependence parameterisation is derived from classical thermodynamic theory by describing effects from changes in molar enthalpy and heat capacity of a multi-component system. Thermodynamic equilibrium data of aqueous organic and water-free organic mixtures from the literature are carefully assessed and complemented with new measurements to establish a comprehensive database, covering a wide temperature range (~ 190 to ~ 440 K) for many of the functional group combinations considered. Different experimental data types and their processing for the estimation of AIOMFAC model parameters are discussed. The new AIOMFAC parameterisation for the temperature dependence of activity coefficients from low to high temperatures shows an overall improvement of 28% in

  20. Bisphenol A is released from used polycarbonate animal cages into water at room temperature

    Science.gov (United States)

    Howdeshell, Kembra L.; Peterman, Paul H.; Judy, Barbara M.; Taylor, Julia A.; Orazio, Carl E.; Ruhlen, Rachel L.; vom Saal, Frederick S.; Welshons, Wade V.

    2003-01-01

    Bisphenol A (BPA) is a monomer with estrogenic activity that is used in the production of food packaging, dental sealants, polycarbonate plastic, and many other products. The monomer has previously been reported to hydrolyze and leach from these products under high heat and alkaline conditions, and the amount of leaching increases as a function of use. We examined whether new and used polycarbonate animal cages passively release bioactive levels of BPA into water at room temperature and neutral pH. Purified water was incubated at room temperature in new polycarbonate and polysulfone cages and used (discolored) polycarbonate cages, as well as control (glass and used polypropylene) containers. The resulting water samples were characterized with gas chromatography/mass spectrometry (GC/MS) and tested for estrogenic activity using an MCF-7 human breast cancer cell proliferation assay. Significant estrogenic activity, identifiable as BPA by GC/MS (up to 310 micro g/L), was released from used polycarbonate animal cages. Detectable levels of BPA were released from new polycarbonate cages (up to 0.3 micro g/L) as well as new polysulfone cages (1.5 micro g/L), whereas no BPA was detected in water incubated in glass and used polypropylene cages. Finally, BPA exposure as a result of being housed in used polycarbonate cages produced a 16% increase in uterine weight in prepubertal female mice relative to females housed in used polypropylene cages, although the difference was not statistically significant. Our findings suggest that laboratory animals maintained in polycarbonate and polysulfone cages are exposed to BPA via leaching, with exposure reaching the highest levels in old cages.

  1. Spatial and temporal evaluations of estrogenic activity in tap water served by a water plant in Wuhan, China.

    Science.gov (United States)

    Zeng, Qiang; Cao, Wen-Cheng; Xu, Liang; Chen, Yong-Zhe; Yun, Luo-Jia; Liu, Ai-Lin; Zhang, Jing; Lu, Wen-Qing

    2013-05-01

    This study aimed to evaluate the spatial and temporal characteristics of estrogenic activities in tap water served by a water plant in Wuhan, China. Tap water samples were monthly collected from the three sampling sites with different distances of distribution network from the plant during April 2010-March 2011: Min (less than 0.1km), Mid (approximately 4km) and Max (approximately 8km). Estrogenic activities of solid phase-extracted tap waters were measured by using recombinant yeast assay incorporated with and without exogenous metabolic activation system (rat liver S9 fractions) and expressed as 17β-estradiol equivalents (EEQ). Pro-estrogenic and estrogenic activity in tap water ranged from 151.4 to 1395.6pg EEQ/L and 35.2 to 1511pg EEQ/L, respectively. Average pro-estrogenic activity (680.3pg EEQ/L) was significantly higher than estrogenic activity (412.8pg EEQ/L) throughout the whole year. The pro-estrogenic activity significantly increased with the extending of distribution network, and was also statistically correlated with water temperature and pH. However, pro-estrogenic and estrogenic activity was not altered across four seasons. Our results suggest that the pro-estrogenic and estrogenic chemicals are present in tap water served by the water plant. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Investigat ing the effect of surface water – groundwater interactions on stream temperature using D istributed Temperature Sensing and instream temperature model

    DEFF Research Database (Denmark)

    Matheswaran, K.; Blemmer, M.; Mortensen, J.

    2011-01-01

    Surface water–groundwater interactions at the stream interface influences, and at times controls the stream temperature, a critical water property driving biogeochemical processes. This study investigates the effects of these interactions on temperature of Stream Elverdamsåen in Denmark using the...

  3. Ambient temperature aqueous synthesis of ultrasmall copper doped ceria nanocrystals for the water gas shift and carbon monoxide oxidation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Curran, Christopher D. [Department of Chemical and Biomolecular Engineering; Lehigh University; Bethlehem; USA; Lu, Li [Department of Materials Science and Engineering; Lehigh University; Bethlehem; USA; Kiely, Christopher J. [Department of Chemical and Biomolecular Engineering; Lehigh University; Bethlehem; USA; Department of Materials Science and Engineering; McIntosh, Steven [Department of Chemical and Biomolecular Engineering; Lehigh University; Bethlehem; USA

    2018-01-01

    Ultra-small CuxCe1-xO2-δnanocrystals were prepared through a room temperature, aqueous synthesis method, achieving high copper doping and low water gas shift activation energy.

  4. Determination of beta activity in water

    Science.gov (United States)

    Barker, F.B.; Robinson, B.P.

    1963-01-01

    Many elements have one or more naturally radioactive isotopes, and several hundred other radionuclides have been produced artificially. Radioactive substances may be present in natural water as a result of geochemical processes or the release of radioactive waste and other nuclear debris to the environment. The Geological Survey has developed methods for measuring certain of these .radioactive substances in water. Radioactive substances often are present in water samples in microgram quantities or less. Therefore, precautions must be taken to prevent loss of material and to assure that the sample truly represents its source at the time of collection. Addition of acids, complexing agents, or stable isotopes often aids in preventing loss of radioactivity on container walls, on sediment, or on other solid materials in contact with the sample. The disintegration of radioactive atoms is a random process subject to established methods of statistical analysis. Because many water samples contain small amounts of radioactivity, low-level counting techniques must be used. The usual assumption that counting data follow a Gaussian distribution is invalid under these conditions, and statistical analyses must be based on the Poisson distribution. The gross beta activity in water samples is determined from the residue left after evaporation of the sample to dryness. Evaporation is accomplished first in a teflon dish, then the residue is transferred with distilled water to a counting planchet and again is reduced to dryness. The radioactivity on the planchet is measured with an anticoincidence-shielded, low-background, beta counter and is compared with measurements of a strontium-90-yttrium-90 standard prepared and measured in the same manner. Control charts are used to assure consistent operation of the counting instrument.

  5. Integration of space heating and hot water supply in low temperature district heating

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Ommen, Torben Schmidt; Markussen, Michael

    2016-01-01

    of the consumers involves both domestic hot water and space heating. Space heating may be provided at low temperature in low energy buildings. Domestic hot water, however, needs sufficient temperatures to avoid growth of legionella. If the network temperature is below the demand temperature, supplementary heating......District heating may supply many consumers efficiently, but the heat loss from the pipes to the ground is a challenge. The heat loss may be lowered by decreasing the network temperatures for which reason low temperature networks are proposed for future district heating. The heating demand...... is required by the consumer. We study conventional district heating at different temperatures and compare the energy and exergetic efficiency and annual heating cost to solutions that utilize electricity for supplementary heating of domestic hot water in low temperature district heating. This includes direct...

  6. Long Island Sound Water Temperatures During the Last Two Thousand Years

    Science.gov (United States)

    Warren, C. E.; Varekamp, J. C.; Thomas, E.

    2010-12-01

    influenced by the carbonate saturation state of the water. The tetraether index (TEX86) temperature proxy is based on the number of cyclopentane rings in the glycerol dialkyl glycerol tetraethers (GDGTs) from the membrane lipids of marine Crenarchaeota, which changes in response to temperature. Crenarcheota are one of the three major groups of non-thermophilic Archaea, a widely distributed, abundant and ecologically diverse group. This proxy can be used in organic-rich sediments deposited in many different settings. We analyzed samples for TEX86 in LIS cores in order to generate a 2,000 year temperature record. We compare the TEX86 paleotemperature record data (dominantly reflecting surface water temperatures) with a Mg/Ca record based on benthic foraminifera (reflecting bottom water temperatures), and an oxygen isotope record based on benthic foraminifera and corrected for salinity changes by using the Mg/Ca record. The Mg/Ca record appears to show evidence for the Little Ice Age and Medieval Warm Period. Preliminary TEX86 data indicate that temperatures of LIS waters, as averaged over the part of the year that the proxy organisms are biologically active, generally fluctuated between 12-14°C.

  7. Activities in water supply and sanitation.

    Science.gov (United States)

    1997-01-01

    The Economic and Social Council for Asia and the Pacific (ESCAP) held a regional workshop in Thailand in 1992 to demonstrate how women's involvement at all levels of environmentally sound and sustainable water supply and sanitation programs and projects could be made more effective, easier, and productive. Using the same modules, with the support of other organizations such as the Department of Development Support and Management Services, ESCAP conducted four more workshops in the Philippines, Lao People's Democratic Republic (PDR), Vietnam, and Thailand in 1995. In the Philippines, the National Commission on the Role of Filipino Women expressed its intention to adapt the modules for the country. In the Lao PDR, three project ideas were proposed which would assist the Lao Women Union in gaining knowledge on the planning, implementation, operation, and management of water supply and sanitation projects at the national, regional and project levels. In Vietnam, three main directions for action were identified for the promotion of close and active cooperation between the Rural Water Supply and Environmental Sanitation Centres and the system of the Women Union of Vietnam. In Thailand, the National Committee on Health and Environment of the National Commission on Women's Affairs expressed its willingness to seek budgetary allocation for the promotion of women's role in water supply and sanitation.

  8. Activation energy for oxygen chemisorption on carbon at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Teng, H.; Hsieh, C.T. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Chemical Engineering

    1999-01-01

    The kinetics of oxygen chemisorption on resin chars were investigated in this study. The Elovich equation was employed to facilitate the interpretation of the chemisorption process. It was found that the activation energy for chemisorption is not constant and varies with surface coverage. This observation can be explained by a distributed kinetic parameter model, here implemented as a distributed activation energy model. The energy distribution model reveals that the amount of mass uptake obtained in a typical chemisorption study does not involve full coverage of all of the active sites on carbon. It is concluded that the information on active sites obtained from low-temperature chemisorption cannot be directly applied to gasification at higher temperatures.

  9. Polarization induced water molecule dissociation below the first-order electronic-phase transition temperature

    CERN Document Server

    Arulsamy, Andrew Das; Elersic, Kristina; Modic, Martina; Subramani, Uma Shankar

    2011-01-01

    Hydrogen produced from the photocatalytic splitting of water is one of the reliable alternatives to replace the polluting fossil and the radioactive nuclear fuels. Here, we provide unequivocal evidence for the existence of blue- and red-shifting O$-$H covalent bonds within a single water molecule adsorbed on MgO surface as a result of asymmetric displacement polarizabilities. The adsorbed H-O-H on MgO gives rise to one weaker H-O bond, while the other O-H covalent bond from the same adsorbed water molecule compensates this effect with a stronger bond. The weaker bond (nearest to the surface), the interlayer tunneling electrons and the silver substrate are shown to be the causes for the smallest dissociative activation energy on MgO monolayer. The origin that is responsible to initiate the splitting mechanism is proven to be due to the changes in the polarizability of an adsorbed water molecule, which are further supported by the temperature-dependent static dielectric constant measurements for water below the...

  10. Tooth Whitening And Temperature Rise With Two Bleaching Activation Methods

    Science.gov (United States)

    Abu-ElMagd, D. M.; El-Sayad, I. I.; Abd El-Gawad, L. M.

    2009-09-01

    To measure the tooth whitening and the surface and Intrapulpal temperature increase in vitro on freshly extracted upper human central incisors after chemical, Zoom AP light and diode laser activated bleaching. Thirty caries-free upper human incisors were selected. Teeth were divided into three equal groups according to the methods of activation of the bleaching agent (n = 10). A whitening gel containing hydrogen peroxide was applied to the buccal surface of all teeth. Group I was bleached using chemically activated hydrogen peroxide gel, for three applications of 15 min each. Group II was bleached with high intensity advanced power Zoom activation light (Zoom AP), for three applications of 15 min each. Group III was bleached with diode laser activation technique, where the teeth were irradiated with 2 Watt diode laser for three applications of 30 sec each. The whitening degree was assessed using an image analysis system, while temperature rise was recorded using a thermocouple on the external tooth surface and Intrapulpal. The degree of whitening increased significantly in all groups. However, the percentage of whitening was not statistically significantly different between the three groups. In addition, group II showed statistically significant higher mean rise in both surface and pulp temperatures than group I and group III. Chemical bleaching produces the same whitening effect as Zoom AP light and laser, with no surface or pulpal temperature rise. Laser application is faster and produces less surface and pulp temperature increase than Zoom AP light. Diode laser used to activate bleaching gels is not considered dangerous to the vitality of dental pulp using power settings of 2 W.

  11. Low-temperature hydrogen production from water and methanol using Pt/α-MoC catalysts

    Science.gov (United States)

    Lin, Lili; Zhou, Wu; Gao, Rui; Yao, Siyu; Zhang, Xiao; Xu, Wenqian; Zheng, Shijian; Jiang, Zheng; Yu, Qiaolin; Li, Yong-Wang; Shi, Chuan; Wen, Xiao-Dong; Ma, Ding

    2017-03-01

    Polymer electrolyte membrane fuel cells (PEMFCs) running on hydrogen are attractive alternative power supplies for a range of applications, with in situ release of the required hydrogen from a stable liquid offering one way of ensuring its safe storage and transportation before use. The use of methanol is particularly interesting in this regard, because it is inexpensive and can reform itself with water to release hydrogen with a high gravimetric density of 18.8 per cent by weight. But traditional reforming of methanol steam operates at relatively high temperatures (200-350 degrees Celsius), so the focus for vehicle and portable PEMFC applications has been on aqueous-phase reforming of methanol (APRM). This method requires less energy, and the simpler and more compact device design allows direct integration into PEMFC stacks. There remains, however, the need for an efficient APRM catalyst. Here we report that platinum (Pt) atomically dispersed on α-molybdenum carbide (α-MoC) enables low-temperature (150-190 degrees Celsius), base-free hydrogen production through APRM, with an average turnover frequency reaching 18,046 moles of hydrogen per mole of platinum per hour. We attribute this exceptional hydrogen production—which far exceeds that of previously reported low-temperature APRM catalysts—to the outstanding ability of α-MoC to induce water dissociation, and to the fact that platinum and α-MoC act in synergy to activate methanol and then to reform it.

  12. Anomalous dependence of the heat capacity of supercooled water on pressure and temperature

    Directory of Open Access Journals (Sweden)

    I.A. Stepanov

    2014-01-01

    Full Text Available In some papers, dependences of the isobaric heat capacity of water versus pressure and temperature were obtained. It is shown that these dependences contradict both the dependence of heat capacity on temperature for supercooled water, and an important thermodynamic equation for the dependence of heat capacity on pressure. A possible explanation for this contradiction is proposed.

  13. Lateralized Difference in Tympanic Membrane Temperature: Emotion and Hemispheric Activity

    OpenAIRE

    Propper, Ruth E.; Brunyé, Tad T.

    2013-01-01

    We review literature examining relationships between tympanic membrane temperature (TMT), affective/motivational orientation, and hemispheric activity. Lateralized differences in TMT might enable real-time monitoring of hemispheric activity in real-world conditions, and could serve as a corroborating marker of mental illnesses associated with specific affective dysregulation. We support the proposal that TMT holds potential for broadly indexing lateralized brain physiology during tasks demand...

  14. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in the Pacific Remote Island Areas from 2011 to 2016

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  15. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in American Samoa from 2012 to 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  16. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in the Hawaiian Archipelago from 2010 to 2016

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  17. National Coral Reef Monitoring Program: Water Temperature Data from Subsurface Temperature Recorders (STRs) deployed at coral reef sites in the Marianas Archipelago from 2011 to 2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature data are collected using subsurface temperature recorders (STRs) that aid in the monitoring of seawater temperature variability at permanent coral...

  18. Biodegradation of Toluene Under Seasonal and Diurnal Fluctuations of Soil-Water Temperature.

    KAUST Repository

    Yadav, Brijesh K

    2012-05-12

    An increasing interest in bioremediation of hydrocarbon polluted sites raises the question of the influence of seasonal and diurnal changes on soil-water temperature on biodegradation of BTEX, a widespread group of (sub)-surface contaminants. Therefore, we investigated the impact of a wide range of varying soil-water temperature on biodegradation of toluene under aerobic conditions. To see the seasonal impact of temperature, three sets of batch experiments were conducted at three different constant temperatures: 10°C, 21°C, and 30°C. These conditions were considered to represent (1) winter, (2) spring and/or autumn, and (3) summer seasons, respectively, at many polluted sites. Three additional sets of batch experiments were performed under fluctuating soil-water temperature cases (21<>10°C, 30<>21°C, and 10<>30°C) to mimic the day-night temperature patterns expected during the year. The batches were put at two different temperatures alternatively to represent the day (high-temperature) and night (low-temperature) times. The results of constant- and fluctuating-temperature experiments show that toluene degradation is strongly dependent on soil-water temperature level. An almost two-fold increase in toluene degradation time was observed for every 10°C decrease in temperature for constant-temperature cases. Under fluctuating-temperature conditions, toluene degraders were able to overcome the temperature stress and continued thriving during all considered weather scenarios. However, a slightly longer time was taken compared to the corresponding time at daily mean temperature conditions. The findings of this study are directly useful for bioremediation of hydrocarbon-polluted sites having significant diurnal and seasonal variations of soil-water temperature.

  19. Improving a pavement-watering method on the basis of pavement surface temperature measurements

    CERN Document Server

    Hendel, Martin; Diab, Youssef; Royon, Laurent

    2014-01-01

    Pavement-watering has been studied since the 1990's and is currently considered a promising tool for urban heat island reduction and climate change adaptation. However, possible future water resource availability problems require that water consumption be optimized. Although pavement heat flux can be studied to improve pavement-watering methods (frequency and water consumption), these measurements are costly and require invasive construction work to install appropriate sensors in a dense urban environment. Therefore, we analyzed measurements of pavement surface temperatures in search of alternative information relevant to this goal. It was found that high frequency surface temperature measurements (more than every 5 minutes) made by an infrared camera can provide enough information to optimize the watering frequency. Furthermore, if the water retaining capacity of the studied pavement is known, optimization of total water consumption is possible on the sole basis of surface temperature measurements.

  20. Temperature Activated Diffusion of Radicals through Ion Implanted Polymers

    DEFF Research Database (Denmark)

    Wakelin, Edgar A.; Davies, Michael J.; Bilek, Marcela M. M.

    2015-01-01

    and controlling the diffusion of radicals through this layer will enable efficient optimization of this technique. We develop a model based on site to site diffusion according to Fick's second law with temperature activation according to the Arrhenius relation. Using our model, the Arrhenius exponential prefactor...

  1. Junction temperature estimation for an advanced active power cycling test

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Jørgensen, S.

    2015-01-01

    estimation method using on-state VCE for an advanced active power cycling test is proposed. The concept of the advanced power cycling test is explained first. Afterwards the junction temperature estimation method using on-state VCE and current is presented. Further, the method to improve the accuracy...

  2. A large predatory reef fish species moderates feeding and activity patterns in response to seasonal and latitudinal temperature variation.

    Science.gov (United States)

    Scott, Molly; Heupel, Michelle; Tobin, Andrew; Pratchett, Morgan

    2017-10-11

    Climate-driven increases in ocean temperatures are expected to affect the metabolic requirements of marine species substantially. To mitigate the impacts of increasing temperatures in the short-term, it may be necessary for ectothermic organisms to alter their foraging behaviour and activity. Herein, we investigate seasonal variation in foraging behaviour and activity of latitudinally distinct populations of a large coral reef predator, the common coral trout, Plectropomus leopardus, from the Great Barrier Reef, Australia. P. leopardus exhibited increased foraging frequency in summer versus winter time, irrespective of latitude, however, foraging frequency substantially declined at water temperatures >30 °C. Foraging frequency also decreased with body size but there was no interaction with temperature. Activity patterns were directly correlated with water temperature; during summer, the low-latitude population of P. leopardus spent up to 62% of their time inactive, compared with 43% for the high-latitude population. The impact of water temperature on activity patterns was greatest for larger individuals. These results show that P. leopardus moderate their foraging behaviour and activity according to changes in ambient temperatures. It seems likely that increasing ocean temperatures may impose significant constraints on the capacity of large-bodied fishes to obtain sufficient prey resources while simultaneously conserving energy.

  3. Influence of Tap Water Quality and Household Water Use Activities on Indoor Air and Internal Dose Levels of Trihalomethanes

    Science.gov (United States)

    Nuckols, John R.; Ashley, David L.; Lyu, Christopher; Gordon, Sydney M.; Hinckley, Alison F.; Singer, Philip

    2005-01-01

    Individual exposure to trihalomethanes (THMs) in tap water can occur through ingestion, inhalation, or dermal exposure. Studies indicate that activities associated with inhaled or dermal exposure routes result in a greater increase in blood THM concentration than does ingestion. We measured blood and exhaled air concentrations of THM as biomarkers of exposure to participants conducting 14 common household water use activities, including ingestion of hot and cold tap water beverages, showering, clothes washing, hand washing, bathing, dish washing, and indirect shower exposure. We conducted our study at a single residence in each of two water utility service areas, one with relatively high and the other low total THM in the residence tap water. To maintain a consistent exposure environment for seven participants, we controlled water use activities, exposure time, air exchange, water flow and temperature, and nonstudy THM sources to the indoor air. We collected reference samples for water supply and air (pre–water use activity), as well as tap water and ambient air samples. We collected blood samples before and after each activity and exhaled breath samples at baseline and postactivity. All hot water use activities yielded a 2-fold increase in blood or breath THM concentrations for at least one individual. The greatest observed increase in blood and exhaled breath THM concentration in any participant was due to showering (direct and indirect), bathing, and hand dishwashing. Average increase in blood THM concentration ranged from 57 to 358 pg/mL due to these activities. More research is needed to determine whether acute and frequent exposures to THM at these concentrations have public health implications. Further research is also needed in designing epidemiologic studies that minimize data collection burden yet maximize accuracy in classification of dermal and inhalation THM exposure during hot water use activities. PMID:16002374

  4. Simulating soybean canopy temperature as affected by weather variables and soil water potential

    Science.gov (United States)

    Choudhury, B. J.

    1982-01-01

    Hourly weather data for several clear sky days during summer at Phoenix and Baltimore which covered a wide range of variables were used with a plant atmosphere model to simulate soybean (Glycine max L.) leaf water potential, stomatal resistance and canopy temperature at various soil water potentials. The air and dew point temperatures were found to be the significant weather variables affecting the canopy temperatures. Under identical weather conditions, the model gives a lower canopy temperature for a soybean crop with a higher rooting density. A knowledge of crop rooting density, in addition to air and dew point temperatures is needed in interpreting infrared radiometric observations for soil water status. The observed dependence of stomatal resistance on the vapor pressure deficit and soil water potential is fairly well represented. Analysis of the simulated leaf water potentials indicates overestimation, possibly due to differences in the cultivars.

  5. Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features.

    Science.gov (United States)

    Luoto, Tomi P; Nevalainen, Liisa

    2013-01-01

    Long-term water temperature records are necessary for better understanding climate change impacts on freshwaters. We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses to regional climate variability since the Little Ice Age. Our results indicate divergent trends for the lakes. In two of the lakes, which are located at the sunny southern slope of mountains, water temperature has increased several degrees concurrent with the observed air temperature increase. In contrast, no change is observed in the reconstructed water temperatures of a shaded lake, located at the northern slope, where also the ecological and thermal changes are most subtle. The results indicate the importance of cold water inputs, such as snowmelt and groundwater, on lakes' thermal conditions and suggest that watershed characteristics and lake stratification play a major role in defining the lake-specific thermal regime.

  6. Poly(vinyl methyl ether) hydrogels at temperatures below the freezing point of water-molecular interactions and states of water.

    Science.gov (United States)

    Pastorczak, Marcin; Dominguez-Espinosa, Gustavo; Okrasa, Lidia; Pyda, Marek; Kozanecki, Marcin; Kadlubowski, Slawomir; Rosiak, Janusz M; Ulanski, Jacek

    2014-01-01

    Water interacting with a polymer reveals a number of properties very different to bulk water. These interactions lead to the redistribution of hydrogen bonds in water. It results in modification of thermodynamic properties of water and the molecular dynamics of water. That kind of water is particularly well observable at temperatures below the freezing point of water, when the bulk water crystallizes. In this work, we determine the amount of water bound to the polymer and of the so-called pre-melting water in poly(vinyl methyl ether) hydrogels with the use of Raman spectroscopy, dielectric spectroscopy, and calorimetry. This analysis allows us to compare various physical properties of the bulk and the pre-melting water. We also postulate the molecular mechanism responsible for the pre-melting of part of water in poly(vinyl methyl ether) hydrogels. We suggest that above -60 °C, the first segmental motions of the polymer chain are activated, which trigger the process of the pre-melting.

  7. Strategies to increase the stability of intermediate moisture foods towards Zygosaccharomyces rouxii: the effect of temperature, ethanol, pH and water activity, with or without the influence of organic acids.

    Science.gov (United States)

    Vermeulen, A; Marvig, C L; Daelman, J; Xhaferi, R; Nielsen, D S; Devlieghere, F

    2015-02-01

    Intermediate moisture foods (IMF) are in general microbiologically stable products. However, due to health concerns consumer demands are increasingly forcing producers to lower the fat, sugar and preservatives content, which impede the stability of the IMF products. One of the strategies to counteract these problems is the storage of IMF products at lower temperatures. Thorough knowledge on growth/no growth boundaries of Zygosaccharomyces rouxii in IMF products, also at different storage temperatures is an important tool for ensuring microbiologically stability. In this study, growth/no growth models for Z. rouxii, developed by Vermeulen et al. (2012) were further extended by incorporating the factor temperature. Three different data sets were build: (i) without organic acids, (ii) with acetic acid (10,000 ppm on product basis) and (iii) with sorbic acid (1500 ppm on product basis). For each of these data sets three different growth/no growth models were developed after 30, 60 and 90 days. The results show that the influence of temperature is only significant in the lower temperature range (8-15 °C). Also, the effect of pH is negligible (pH 5.0-6.2) unless organic acids are present. More specific, acetic acid had only an additive effect to ethanol and aw at low pH, whereas sorbic acid had also an additive effect at the higher pH values. For incubation periods longer than 30 days the growth/no growth boundary remained stable but enlarged gradually between day 60 and 90, except for the lower temperature range (<12 °C) where the boundary shifts to more stringent environmental conditions. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Mora-Rodriguez, Ricardo; Ortega, Juan F.; Fernandez-Elias, Valentin E.; Kapsokefalou, Maria; Malisova, Olga; Athanasatou, Adelais; Husemann, Marlien; Domnik, Kirsten; Braun, Hans

    2016-01-01

    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 hydration status (i.e., lower urine and blood osmolality). PMID:27128938

  9. Water sorption properties of Dutch type semi-hard cheese edge in the range of common storing temperatures

    Directory of Open Access Journals (Sweden)

    Maria Carolina Soares Pereira

    2011-01-01

    Full Text Available Moisture sorption isotherms of Dutch type semi-hard cheese edge in the temperature range of 10–25 ºC and water activity (Aw from 0.11 to 0.98 were determined using manometric method. The sorption curves had a sigmoid shape. The equilibrium moisture content (EMC of cheese samples increased with an increase in Aw at a constant temperature both for water adsorption and desorption. An increase in temperature caused an increase in Aw for the same moisture content (MC and, if Aw was kept constant, an increase in temperature caused a decrease in the amount of absorbed water. Critical values of equilibrium moisture content, corresponding to the Aw = 0.6, were between 11 % MC (w.b. and 17 % MC (w.b. both for moisture adsorption and desorption. Values of sorption heat were calculated from moisture sorption isotherms by applying the Clausius-Clapeyron equation. Values of the heat of desorption are higher than those of adsorption and the difference increases with the MC decrease. Heat of sorption decreased from 48.5 kJ/mol (~5.5 % MC w.b. to the values approaching the heat of vaporization of pure water, free MC. The critical value for free water evaporation is about w = 27 % (w.b. for the range of temperature 10–25 ºC.

  10. Water sorption isotherms of skimmed milk powder within the temperature range of 5–20 °C

    Directory of Open Access Journals (Sweden)

    Jitka Langová

    2012-01-01

    Full Text Available Moisture sorption isotherms (MSI’s of skimmed milk powder in the temperature range of 5–20 °C were determined using manometric method. MSI’s, which show the water content versus water activity (Aw at a constant temperature, are used to describe relationships between water content and equilibrium state relative vapour pressure (RVP. The equilibrium moisture content (EMC of skimmed milk powder samples is growing with an increase of Aw at a constant temperature both for water adsorption and desorption. Isotherms were found to be type II of Brunauer-Emmett-Teller classification. It is the type most common for foods. The shape of created isotherms was sigmoid. Structural modifications of crystals were observed during adsorption in the microscope, too. Critical value of EMC of tested samples corresponding to the Aw equal to 0.6 for adsorption was 6.50% MC (w.b. at temperature 5 °C, 9.15% MC (w.b. at temperature 10 °C, and 7.71% MC (w.b. at temperature 20 °C. These values determine optimal conditions for storage from the point of view microorganisms grow, Aw<0.6.

  11. Water Wisdom: 23 Stand-Alone Activities on Water Supply and Water Conservation for High School Students. 2nd Edition.

    Science.gov (United States)

    Massachusetts State Water Resources Authority, Boston.

    This water conservation education program for high schools consists of both stand-alone activities and teacher support materials. Lessons are divided into six broad categories: (1) The Water Cycle; (2) Water and Society; (3) Keeping Water Pure; (4) Visualizing Volumes; (5) The Economics of Water Use; and (6) Domestic Water Conservation. The…

  12. What Determines Water Temperature Dynamics in the San Francisco Bay-Delta System?

    Science.gov (United States)

    Vroom, J.; van der Wegen, M.; Martyr-Koller, R. C.; Lucas, L. V.

    2017-11-01

    Water temperature is an important factor determining estuarine species habitat conditions. Water temperature is mainly governed by advection (e.g., from rivers) and atmospheric exchange processes varying strongly over time (day-night, seasonally) and the spatial domain. On a long time scale, climate change will impact water temperature in estuarine systems due to changes in river flow regimes, air temperature, and sea level rise. To determine which factors govern estuarine water temperature and its sensitivity to changes in its forcing, we developed a process-based numerical model (Delft3D Flexible Mesh) and applied it to a well-monitored estuarine system (the San Francisco Estuary) for validation. The process-based approach allows for detailed process description and a physics-based analysis of governing processes. The model was calibrated for water year 2011 and incorporated 3-D hydrodynamics, salinity intrusion, water temperature dynamics, and atmospheric coupling. Results show significant skill in reproducing temperature observations on daily, seasonal, and yearly time scales. In North San Francisco Bay, thermal stratification is present, enhanced by salinity stratification. The temperature of the upstream, fresh water Delta area is captured well in 2-D mode, although locally—on a small scale—vertical processes (e.g., stratification) may be important. The impact of upstream river temperature and discharge and atmospheric forcing on water temperatures differs throughout the Delta, possibly depending on dispersion and residence times. Our modeling effort provides a sound basis for future modeling studies including climate change impact on water temperature and associated ecological modeling, e.g., clam and fish habitat and phytoplankton dynamics.

  13. SU-F-T-492: The Impact of Water Temperature On Absolute Dose Calibration

    Energy Technology Data Exchange (ETDEWEB)

    Islam, N [State University of New York at Buffalo, Buffalo, NY (United States); Podgorsak, M [State University of New York at Buffalo, Buffalo, NY (United States); Roswell Park Cancer Institute, Buffalo, NY (United States)

    2016-06-15

    Purpose: The Task Group 51 (TG 51) protocol prescribes that dose calibration of photon beams be done by irradiating an ionization chamber in a water tank at pre-defined depths. Methodologies are provided to account for variations in measurement conditions by applying correction factors. However, the protocol does not completely account for the impact of water temperature. It is well established that water temperature will influence the density of air in the ion chamber collecting volume. Water temperature, however, will also influence the size of the collecting volume via thermal expansion of the cavity wall and the density of the water in the tank. In this work the overall effect of water temperature on absolute dosimetry has been investigated. Methods: Dose measurements were made using a Farmer-type ion chamber for 6 and 23 MV photon beams with water temperatures ranging from 10 to 40°C. A reference ion chamber was used to account for fluctuations in beam output between successive measurements. Results: For the same beam output, the dose determined using TG 51 was dependent on the temperature of the water in the tank. A linear regression of the data suggests that the dependence is statistically significant with p-values of the slope equal to 0.003 and 0.01 for 6 and 23 MV beams, respectively. For a 10 degree increase in water phantom temperature, the absolute dose determined with TG 51 increased by 0.27% and 0.31% for 6 and 23 MV beams, respectively. Conclusion: There is a measurable effect of water temperature on absolute dose calibration. To account for this effect, a reference temperature can be defined and a correction factor applied to account for deviations from this reference temperature during beam calibration. Such a factor is expected to be of similar magnitude to most of the existing TG 51 correction factors.

  14. Identifying (subsurface) anthropogenic heat sources that influence temperature in the drinking water distribution system

    Science.gov (United States)

    Agudelo-Vera, Claudia M.; Blokker, Mirjam; de Kater, Henk; Lafort, Rob

    2017-09-01

    The water temperature in the drinking water distribution system and at customers' taps approaches the surrounding soil temperature at a depth of 1 m. Water temperature is an important determinant of water quality. In the Netherlands drinking water is distributed without additional residual disinfectant and the temperature of drinking water at customers' taps is not allowed to exceed 25 °C. In recent decades, the urban (sub)surface has been getting more occupied by various types of infrastructures, and some of these can be heat sources. Only recently have the anthropogenic sources and their influence on the underground been studied on coarse spatial scales. Little is known about the urban shallow underground heat profile on small spatial scales, of the order of 10 m × 10 m. Routine water quality samples at the tap in urban areas have shown up locations - so-called hotspots - in the city, with relatively high soil temperatures - up to 7 °C warmer - compared to the soil temperatures in the surrounding rural areas. Yet the sources and the locations of these hotspots have not been identified. It is expected that with climate change during a warm summer the soil temperature in the hotspots can be above 25 °C. The objective of this paper is to find a method to identify heat sources and urban characteristics that locally influence the soil temperature. The proposed method combines mapping of urban anthropogenic heat sources, retrospective modelling of the soil temperature, analysis of water temperature measurements at the tap, and extensive soil temperature measurements. This approach provided insight into the typical range of the variation of the urban soil temperature, and it is a first step to identifying areas with potential underground heat stress towards thermal underground management in cities.

  15. Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems

    NARCIS (Netherlands)

    Luostarinen, S.; Sanders, W.T.M.; Kujawa-Roeleveld, K.; Zeeman, G.

    2007-01-01

    The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The

  16. Simulating sunflower canopy temperatures to infer root-zone soil water potential

    Science.gov (United States)

    Choudhury, B. J.; Idso, S. B.

    1983-01-01

    A soil-plant-atmosphere model for sunflower (Helianthus annuus L.), together with clear sky weather data for several days, is used to study the relationship between canopy temperature and root-zone soil water potential. Considering the empirical dependence of stomatal resistance on insolation, air temperature and leaf water potential, a continuity equation for water flux in the soil-plant-atmosphere system is solved for the leaf water potential. The transpirational flux is calculated using Monteith's combination equation, while the canopy temperature is calculated from the energy balance equation. The simulation shows that, at high soil water potentials, canopy temperature is determined primarily by air and dew point temperatures. These results agree with an empirically derived linear regression equation relating canopy-air temperature differential to air vapor pressure deficit. The model predictions of leaf water potential are also in agreement with observations, indicating that measurements of canopy temperature together with a knowledge of air and dew point temperatures can provide a reliable estimate of the root-zone soil water potential.

  17. Effect of cold-water immersion duration on body temperature and muscle function.

    Science.gov (United States)

    Peiffer, Jeremiah J; Abbiss, Chris R; Watson, Greig; Nosaka, Ken; Laursen, Paul B

    2009-08-01

    This study compared the effect of 5, 10 and 20 min of cold-water (14 degrees C) immersion on rectal and muscle temperature and neuromuscular function. Twelve cyclists performed four cycling time-to-exhaustion trials in hot conditions (40 degrees C and 40%rh), followed 25 min later by cold-water immersion for 5, 10 or 20 min or 20 min in room temperature (24 degrees C; control). Rectal temperature was measured continuously, and muscle temperature was measured before, immediately after and 45 min after the time-to-exhaustion-test, as well as before and after water immersion. Sixty-second maximal voluntary isometric torque and isokinetic torque of the knee extensors were measured before, immediately after and 55 min after time-to-exhaustion-test. A greater rate of decrease in rectal temperature was observed in all water immersion conditions 45-80 min after time-to-exhaustion-test compared with control. Compared with control, muscle temperature 45 min after time-to-exhaustion-test was lower for all water immersion conditions; however, muscle temperature was lower for the 10- and 20-min conditions compared with 5 min. Isometric torque measured 55 min after time-to-exhaustion-test was lower for all conditions. Isokinetic torque was lower for all conditions immediately and 55-min post-time-to-exhaustion-test. Of the durations measured, 5 min of cold-water immersion appeared as the most appropriate duration for reducing rectal temperature but limiting decreases in muscle temperature.

  18. Water Pollution Scrubber Activity Simulates Pollution Control Devices.

    Science.gov (United States)

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

    2003-01-01

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

  19. Active disturbance rejection control of temperature for ultrastable optical cavities.

    Science.gov (United States)

    Pizzocaro, Marco; Calonico, Davide; Calosso, Claudio; Clivati, Cecilia; Costanzo, Giovanni A; Levi, Filippo; Mura, Alberto

    2013-02-01

    This paper describes the application of a novel active disturbance rejection control (ADRC) to the stabilization of the temperature of two ultra-stable Fabry-Perot cavities. The cavities are 10 cm long and entirely made of ultralow- expansion glass. The control is based on a linear extended state observer that estimates and compensates the disturbance in the system in real time. The resulting control is inherently robust and easy to tune. A digital implementation of ADRC gives a temperature instability of 200 μK at one day of integration time.

  20. Removal of toxic chemicals from water with activated carbon

    Science.gov (United States)

    Dawson, V.K.; Marking, L.L.; Bills, T.D.

    1976-01-01

    Activated carbon was effective in removing fish toxicants and anesthetics from water solutions. Its capacity to adsorb 3-trifluoromethyl-4-nitrophenol (TFM), antimycin, NoxfishA? (5% rotenone), Dibrorms, juglone, MSa??222, and benzocaine ranged from 0.1 to 64 mg per gram of carbon. The adsorptive capacity (end point considered as a significant discharge) of activated carbon for removal of TFM was determined at column depths of 15, 30, and 60 cm; temperatures of 7, 12, 17, and 22 C; pH's of 6.5, 7.5, 8.5, and 9.5; and flow rates of 50, 78, 100, 200, and 940 ml/min. Adsorptive capacity increased when the contact time was increased by reducing the flow rate or increasing the column depth. The adsorptive capacity was not significantly influenced by temperature but was substantially higher at pH 6.5 than at the other pH's tested. A practical and efficient filter for purifying chemically treated water was developed.

  1. RELATIONS BETWEEN GRACE-DERIVED WATER STORAGE CHANGE WITH PRECIPITATION AND TEMPERATURE OVER KAIDU RIVER BASIN, CHINA

    Directory of Open Access Journals (Sweden)

    J. Huang

    2016-06-01

    Full Text Available Water is essential for human survival and well-being, and important to virtually all sectors of the economy. In the aridzone of China’s west, water resource is the controlling factor on the distribution of human settlements. Water cycle variation is sensitive to temperature and precipitation, which are influenced by human activity and climate change. Satellite observations of Earth’s time-variable gravity field from the Gravity Recovery and Climate Experiment (GRACE mission, which enable direct measurement of changes of total terrestrial water storage, could be useful to aid this modelling. In this pilot study, TWS change from 2002 to 2013 obtained from GRACE satellite mission over the Kaidu River Basin in Xinjiang, China is presented. Precipitation and temperature data from in-situ station and National Satellite Meteorological Centre of China (NSMC are analysed to examine whether there is a statistically significant correlation between them.

  2. Comparison of the Melting Temperatures of Classical and Quantum Water Potential Models

    Science.gov (United States)

    Du, Sen; Yoo, Soohaeng; Li, Jinjin

    2017-08-01

    As theoretical approaches and technical methods improve over time, the field of computer simulations for water has greatly progressed. Water potential models become much more complex when additional interactions and advanced theories are considered. Macroscopic properties of water predicted by computer simulations using water potential models are expected to be consistent with experimental outcomes. As such, discrepancies between computer simulations and experiments could be a criterion to comment on the performances of various water potential models. Notably, water can occur not only as liquid phases but also as solid and vapor phases. Therefore, the melting temperature related to the solid and liquid phase equilibrium is an effective parameter to judge the performances of different water potential models. As a mini review, our purpose is to introduce some water models developed in recent years and the melting temperatures obtained through simulations with such models. Moreover, some explanations referred to in the literature are described for the additional evaluation of the water potential models.

  3. Sensing the water content of honey from temperature-dependent electrical conductivity

    Science.gov (United States)

    In order to predict water content in honey, electrical conductivity was measured on blossom honey types of milk-vetch, jujube and yellow-locust with water content of 18%-37% between 5-40ºC. Regression models of electrical conductivity were developed as functions of water content and temperature. The...

  4. Parameterizing deep water percolation improves subsurface temperature simulations by a multilayer firn model.

    NARCIS (Netherlands)

    Marchenko, S.; van Pelt, W.J.J.; Claremar, B.; Machguth, H.; Reijmer, C.H.; Pettersson, R.; Pohjola, V.A.

    2017-01-01

    Deep preferential percolation of melt water in snow and firn brings water lower along the vertical profile than a laterally homogeneous wetting front. This widely recognized process is an important source of uncertainty in simulations of subsurface temperature, density, and water content in seasonal

  5. Investigating the effects of methanol-water vapor mixture on a PBI-based high temperature PEM fuel cell

    DEFF Research Database (Denmark)

    Araya, Samuel Simon; Andreasen, Søren Juhl; Nielsen, Heidi Venstrup

    2012-01-01

    This paper investigates the effects of methanol and water vapor on the performance of a high temperature proton exchange membrane fuel cell (HT-PEMFC). A H3PO4-doped polybenzimidazole (PBI) membrane electrode assembly (MEA), Celtec P2100 of 45 cm2 of active surface area from BASF was employed....... A long-term durability test of around 1250 h was performed, in which the concentrations of methanol-water vapor mixture in the anode feed gas were varied. The fuel cell showed a continuous performance decay in the presence of vapor mixtures of methanol and water of 5% and 8% by volume in anode feed...

  6. Kinetics of acrylamide formation/elimination reactions as affected by water activity.

    Science.gov (United States)

    De Vleeschouwer, Kristel; Van der Plancken, Iesel; Van Loey, Ann; Hendrickx, Marc E

    2007-01-01

    The influence of water activity on the kinetics of acrylamide formation and elimination reaction was investigated using low-moisture equimolar asparagine-glucose model systems, which were heated at temperatures between 120 and 200 degrees C for variable heating times. To determine the water content corresponding to the water activities tested, a sorption moisture isotherm was constructed experimentally. The acrylamide concentrations measured at different water activities could be modeled on the basis of a reaction scheme including not only acrylamide formation and elimination reactions but also an alternative Maillard reaction between both reactants. The corresponding rate constants and activation energies were estimated using nonlinear regression analysis. Whereas the rate constant for acrylamide formation varied only slightly with the initial water activity of the model system, the elimination rate constant showed a clear minimum around a water activity of 0.82. The opposite trend, namely, a maximum at a water activity of 0.82, was found for the Maillard reaction rate constant as a function of water activity, which confirms data from literature. The activation energies for the different reactions changed in a comparable way as the corresponding rate constant with water activity.

  7. Discharge, water temperature, and selected meteorological data for Vancouver Lake, Vancouver, Washington, water years 2011-13

    Science.gov (United States)

    Foreman, James R.; Marshall, Cameron A.; Sheibley, Rich W.

    2014-01-01

    The U.S. Geological Survey partnered with the Vancouver Lake Watershed Partnership in a 2-year intensive study to quantify the movement of water and nutrients through Vancouver Lake in Vancouver, Washington. This report is intended to assist the Vancouver Lake Watershed Partnership in evaluating potential courses of action to mitigate seasonally driven blooms of harmful cyanobacteria and to improve overall water quality of the lake. This report contains stream discharge, lake water temperature, and selected meteorological data for water years 2011, 2012, and 2013 that were used to develop the water and nutrient budgets for the lake.

  8. Water heater temperature set point and water use patterns influence Legionella pneumophila and associated microorganisms at the tap.

    Science.gov (United States)

    Rhoads, William J; Ji, Pan; Pruden, Amy; Edwards, Marc A

    2015-12-01

    Lowering water heater temperature set points and using less drinking water are common approaches to conserving water and energy; yet, there are discrepancies in past literature regarding the effects of water heater temperature and water use patterns on the occurrence of opportunistic pathogens, in particular Legionella pneumophila. Our objective was to conduct a controlled, replicated pilot-scale investigation to address this knowledge gap using continuously recirculating water heaters to examine five water heater set points (39-58 °C) under three water use conditions. We hypothesized that L. pneumophila levels at the tap depend on the collective influence of water heater temperature, flow frequency, and the resident plumbing ecology. We confirmed temperature setting to be a critical factor in suppressing L. pneumophila growth both in continuously recirculating hot water lines and at distal taps. For example, at 51 °C, planktonic L. pneumophila in recirculating lines was reduced by a factor of 28.7 compared to 39 °C and was prevented from re-colonizing biofilm. However, L. pneumophila still persisted up to 58 °C, with evidence that it was growing under the conditions of this study. Further, exposure to 51 °C water in a low-use tap appeared to optimally select for L. pneumophila (e.g., 125 times greater numbers than in high-use taps). We subsequently explored relationships among L. pneumophila and other ecologically relevant microbes, noting that elevated temperature did not have a general disinfecting effect in terms of total bacterial numbers. We documented the relationship between L. pneumophila and Legionella spp., and noted several instances of correlations with Vermamoeba vermiformis, and generally found that there is a dynamic relationship with this amoeba host over the range of temperatures and water use frequencies examined. Our study provides a new window of understanding into the microbial ecology of potable hot water systems and helps to resolve

  9. Relating subsurface temperature changes to microbial activity at a crude oil-contaminated site

    Science.gov (United States)

    Warren, Ean; Bekins, Barbara A.

    2015-01-01

    Crude oil at a spill site near Bemidji, Minnesota has been undergoing aerobic and anaerobic biodegradation for over 30 years, creating a 150–200 m plume of primary and secondary contaminants. Microbial degradation generates heat that should be measurable under the right conditions. To measure this heat, thermistors were installed in wells in the saturated zone and in water-filled monitoring tubes in the unsaturated zone. In the saturated zone, a thermal groundwater plume originates near the residual oil body with temperatures ranging from 2.9 °C above background near the oil to 1.2 °C down gradient. Temperatures in the unsaturated zone above the oil body were up to 2.7 °C more than background temperatures. Previous work at this site has shown that methane produced from biodegradation of the oil migrates upward and is oxidized in a methanotrophic zone midway between the water table and the surface. Enthalpy calculations and observations demonstrate that the temperature increases primarily result from aerobic methane oxidation in the unsaturated zone above the oil. Methane oxidation rates at the site independently estimated from surface CO2 efflux data are comparable to rates estimated from the observed temperature increases. The results indicate that temperature may be useful as a low-cost measure of activity but care is required to account for the correct heat-generating reactions, other heat sources and the effects of focused recharge.

  10. Effect of water temperature on diuresis-natriuresis: AVP, ANP, and urodilatin during immersion in men

    Science.gov (United States)

    Nakamitsu, S.; Sagawa, S.; Miki, K.; Wada, F.; Nagaya, K.; Keil, L. C.; Drummer, C.; Gerzer, R.; Greenleaf, J. E.; Hong, S. K.

    1994-01-01

    Effects of water temperature on diuresis, natriuresis, and associated endocrine responses during head-out immersion were studied in eight men during four 5-h experimental conditions: air control at 28 C and immersion at 34.5 C (thermoneutral (Tnt)), 36 C (above Tnt (aTnt)), and 32 C (below Tnt (bTnt). Esophageal temperature decreased by approximately 0.4 C in bTnt and increased by approximately 0.5 C in aTnt. Cardiac output increased by approximately 80% in aTnt and approximately 40% in bTnt while thoracic impedance, an index of central blood pooling, decreased by 7.5 ohms in bTnt (NS vs. Tnt) and 8.8 ohms in aTnt. Total peripheral resistance decreased at all temperatures (50% in aTnt, 20% in bTnt). Urine flow and Na(+) excretion increased by sixfold in bTnt and Tnt but by only threefold in aTnt. Creatinine clearance was unchanged while osmolal clearance (but not free water clearance) increased two-fold with all immersions. Plasma atrial natriuretic peptide (ANP), urinary urodilatin, and urinary guanosine 3',5'-cyclic monophosphate increased while plasma renin activity, aldosterone, and arginine vasopressin (AVP) decreased similarly at all temperatures. bTnt did not potentiate diuresis by selective attenuation of AVP. The overall natriuretic response exhibited a higher correlation with urodilatin than with ANP. Because diuresis and natriuresis were significantly attenuated in aTnt where central blood pooling was greater, we conclude that mechanisms other than the atrial stretch receptor reflex, i.e., urodilatin and effective arterial blood volume, may play more predominant roles in the mechanism of immersion-induced diuresis and natriuresis.

  11. Modeling Electricity Sector Vulnerabilities and Costs Associated with Water Temperatures Under Scenarios of Climate Change

    Science.gov (United States)

    Macknick, J.; Miara, A.; Brinkman, G.; Ibanez, E.; Newmark, R. L.

    2014-12-01

    The reliability of the power sector is highly vulnerable to variability in the availability and temperature of water resources, including those that might result from potential climatic changes or from competition from other users. In the past decade, power plants throughout the United States have had to shut down or curtail generation due to a lack of available water or from elevated water temperatures. These disruptions in power plant performance can have negative impacts on energy security and can be costly to address. Analysis of water-related vulnerabilities requires modeling capabilities with high spatial and temporal resolution. This research provides an innovative approach to energy-water modeling by evaluating the costs and reliability of a power sector region under policy and climate change scenarios that affect water resource availability and temperatures. This work utilizes results from a spatially distributed river water temperature model coupled with a thermoelectric power plant model to provide inputs into an electricity production cost model that operates on a high spatial and temporal resolution. The regional transmission organization ISO-New England, which includes six New England states and over 32 Gigawatts of power capacity, is utilized as a case study. Hydrological data and power plant operations are analyzed over an eleven year period from 2000-2010 under four scenarios that include climate impacts on water resources and air temperatures as well as strict interpretations of regulations that can affect power plant operations due to elevated water temperatures. Results of these model linkages show how the power sector's reliability and economic performance can be affected by changes in water temperatures and water availability. The effective reliability and capacity value of thermal electric generators are quantified and discussed in the context of current as well as potential future water resource characteristics.

  12. Temperature distributions in trapezoidal built in storage solar water heaters with/without phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Tarhan, Sefa; Yardim, M. Hakan [Department of Farm Machinery, Faculty of Agriculture, Gaziosmanpasa University, Tasliciftlik Yerleskesi, 60240 Tokat (Turkey); Sari, Ahmet [Department of Chemistry, Faculty of Arts and Sciences, Gaziosmanpasa University, Tasliciftlik Yerleskesi, 60240 Tokat (Turkey)

    2006-09-15

    Built in storage solar water heaters (BSSWHs) have been recognized for their more compact constructions and faster solar gain than conventional solar water heaters, however, their water temperatures quickly go down during the cooling period. A trapezoidal BSSWH without PCM storage unit was used as the control heater (reference) to investigate the effect of two differently configured PCM storage units on the temperature distributions in water tanks. In the first design, myristic acid was filled into the PCM storage tank, which also served as an absorbing plate. In the second design, lauric acid was filled into the PCM storage tank, which also served as a baffle plate. The water temperature changes were followed by five thermocouples placed evenly and longitudinally into each of the three BSSWHs. The effects of the PCMs on the water temperature distributions depended on the configuration of the PCM storage unit and the longitudinal position in the water tanks. The use of lauric acid lowered the values of the peak temperatures by 15% compared to the control heater at the upper portion of the water tanks because of the low melting temperature of lauric acid, but it did not have any consistent effect on the retention of the water temperatures during the cooling period. The ability of the myristic acid storage unit to retain the water temperatures got more remarkable, especially at the middle portion of the water tank. The myristic acid storage increased the dip temperatures by approximately 8.8% compared to the control heater. In conclusion, lauric acid storage can be used to stabilize the water temperature during the day time, while the myristic acid storage unit can be used as a thermal barrier against heat loss during the night time because of its relatively high melting temperature and low heat conduction coefficient in its solid phase. The experimental results have also indicated that the thermal characteristics of the PCM and the configuration of the PCM storage

  13. Underwater Depth and Temperature Sensing Based on Fiber Optic Technology for Marine and Fresh Water Applications.

    Science.gov (United States)

    Duraibabu, Dinesh Babu; Leen, Gabriel; Toal, Daniel; Newe, Thomas; Lewis, Elfed; Dooly, Gerard

    2017-05-27

    Oceanic conditions play an important role in determining the effects of climate change and these effects can be monitored through the changes in the physical properties of sea water. In fact, Oceanographers use various probes for measuring the properties within the water column. CTDs (Conductivity, Temperature and Depth) provide profiles of physical and chemical parameters of the water column. A CTD device consists of Conductivity (C), Temperature (T) and Depth (D) probes to monitor the water column changes with respect to relative depth. An optical fibre-based point sensor used as a combined pressure (depth) and temperature sensor and the sensor system are described. Measurements accruing from underwater trials of a miniature sensor for pressure (depth) and temperature in the ocean and in fresh water are reported. The sensor exhibits excellent stability and its performance is shown to be comparable with the Sea-Bird Scientific commercial sensor: SBE9Plus.

  14. Underwater Depth and Temperature Sensing Based on Fiber Optic Technology for Marine and Fresh Water Applications

    Directory of Open Access Journals (Sweden)

    Dinesh Babu Duraibabu

    2017-05-01

    Full Text Available Oceanic conditions play an important role in determining the effects of climate change and these effects can be monitored through the changes in the physical properties of sea water. In fact, Oceanographers use various probes for measuring the properties within the water column. CTDs (Conductivity, Temperature and Depth provide profiles of physical and chemical parameters of the water column. A CTD device consists of Conductivity (C, Temperature (T and Depth (D probes to monitor the water column changes with respect to relative depth. An optical fibre-based point sensor used as a combined pressure (depth and temperature sensor and the sensor system are described. Measurements accruing from underwater trials of a miniature sensor for pressure (depth and temperature in the ocean and in fresh water are reported. The sensor exhibits excellent stability and its performance is shown to be comparable with the Sea-Bird Scientific commercial sensor: SBE9Plus.

  15. Effect of Climate Change on Water Temperature and Attainment of Water Temperature Criteria in the Yaquina Estuary, Oregon (USA)

    Science.gov (United States)

    There is increasing evidence that our planet is warming and this warming is also resulting in rising sea levels. Estuaries which are located at the interface between land and ocean are impacted by these changes. We used CE-QUAL-W2 water quality model to predict changes in water...

  16. An experimental study on the influence of water stagnation and temperature change on water quality in a full-scale domestic drinking water system.

    Science.gov (United States)

    Zlatanović, Lj; van der Hoek, J P; Vreeburg, J H G

    2017-10-15

    The drinking water quality changes during the transport through distribution systems. Domestic drinking water systems (DDWSs), which include the plumbing between the water meter and consumer's taps, are the most critical points in which water quality may be affected. In distribution networks, the drinking water temperature and water residence time are regarded as indicators of the drinking water quality. This paper describes an experimental research on the influence of stagnation time and temperature change on drinking water quality in a full-scale DDWS. Two sets of stagnation experiments, during winter and summer months, with various stagnation intervals (up to 168 h of stagnation) were carried out. Water and biofilms were sampled at two different taps, a kitchen and a shower tap. Results from this study indicate that temperature and water stagnation affect both chemical and microbial quality in DDWSs, whereas microbial parameters in stagnant water appear to be driven by the temperature of fresh water. Biofilm formed in the shower pipe contained more total and intact cells than the kitchen pipe biofilm. Alphaproteobacteria were found to dominate in the shower biofilm (78% of all Proteobacteria), while in the kitchen tap biofilm Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria were evenly distributed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. [EFFECT OF TEMPERATURE ON THE VIABILITY OF PLANKTON CELLS AND MODEL LEGIONELLA PNEUMOPHILA BIOFILMS IN WATER].

    Science.gov (United States)

    Tartakovsky, I S; Karpoval, T I; Gruzdeva, O A; Marinenko, O V; Dronina, Yu E

    2015-01-01

    Study the effect of water temperature from 40 to 70 degrees C on viability of plankton forms and model Legionella pneumophila under experimental conditions. Monospecies legionella biofilms, obtained in plates for enzyme immunoassay during 96 hours at 28 degrees C, and water suspension of BCYE agar cultivated cells of L. pneumophila at a concentration of 10(3) - 10(5) CFU per liter were used in the study for evaluation of bactericidal effect of temperature on various legionella forms. Analysis of effects of various temperature regimens on plankton forms and model legionella biofilms has shown that at a temperature range from 50 to 60 degrees C a significant reduction of quantity of viable legionella cells occurs. Model legionella biofilms have partially conserved viability at a temperature of 60 degrees C and only exposition to a temperature of 70 degrees C resulted in death of legionella biofilms and plankton forms of bacteria. A dependence of viability conservation of legionella from the initial concentration of the causative agent in water and duration of exposition at varying temperature was shown. Short-term heating at a temperature of at least 70 degrees C has the most pronounced bactericidal effect on plankton forms and model L. pneumophila biofilms under experimental conditions. Such temperature regimen could be used as one of the prophylaxis approaches during maintenance of especially dangerous water system and, fist of all, systems of hot water supply.

  18. Perspectives on Temperature in the Pacific Northwest's Fresh Waters

    Energy Technology Data Exchange (ETDEWEB)

    Coutant, C.C.

    1999-06-01

    This report provides a perspective on environmental water temperatures in the Pacific Northwest as they relate to the establishment of water temperature standards by the state and their review by the US Environmental Protection Agency. It is a companion to other detailed reviews of the literature on thermal effects on organisms important to the region. Many factors, both natural and anthropogenic, affect water temperatures in the region. Different environmental zones have characteristic temperatures and mechanisms that affect them. There are specific biotic adaptations to environmental temperatures. Life-cycle strategies of salmonids, in particular, are attuned to annual temperature patterns. Physiological and behavioral requirements on key species form the basis of present water temperature criteria, but may need to be augmented with more concern for environmental settings. There are many issues in the setting of standards, and these are discussed. There are also issues in compliance. Alternative temperature-regulating mechanisms are discussed, as are examples of actions to control water temperatures in the environment. Standards-setting is a social process for which this report should provide background and outline options, alternatives, limitations, and other points for discussion by those in the region.

  19. Response of fish to different simulated rates of water temperature increase

    Energy Technology Data Exchange (ETDEWEB)

    Wike, L.D.; Tuckfield, R.C.

    1992-08-01

    We initiated this study to define the limits of effluent-temperature rate increases during reactor restart, which will help minimize fish kills. We constructed an apparatus for exposing fish to various temperature-increase regimens and conducted two experiments based on information from system tests and scoping runs. In the rate experiment, we acclimated the fish to 20{degree}C, and then raised the temperature to 40{degree}C at varying rates. Because scoping runs and literature suggested that acclimation temperature may affect temperature-related mortality, we conducted an acclimation experiment. We acclimated the fish to various temperatures, then raised the temperatures to 39--40{degree}C at a rate of 2{degree}C every 12 hours. Based on the analysis of the data, we recommend temperature-increase rates during reactor restart of 2.5{degree}C every nine hours if ambient water temperatures are over 20{degree}C. If water temperatures are at or below 20{degree}C, we recommend temperature-increase rates of 2.5{degree}C every 12 hours. No regulation of temperature is required after effluent temperatures reach 40{degree}C. We recommend further studies, including expanded testing with the simulation system and behavioral and bioenergetic investigations that may further refine acceptable rates of effluent-temperature increases.

  20. Temperature and concentration dependences of the activity coefficients of electrolytes

    Science.gov (United States)

    Tikhonov, N. A.; Sidel'nikov, G. B.

    2017-10-01

    A model has been suggested that describes the interaction of hydrated ions in electrolytes and allows the calculation of the main physical effects. The model explains the character of the curves of the activity coefficients. Binary solutions of uni-univalent electrolytes at concentrations from zero to several moles per liter and at temperatures from zero to a few dozens of degrees were studied. The results of simulation were verified by comparing them with many literature data.

  1. Salinity and water temperature data from the Coastal Waters of Washington/Oregon from 01 March 2001 to 31 December 2001 (NODC Accession 0001142)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salinity and water temperature data were collected using conductivity sensor and temperature probe in the Coastal Waters of Washington/Orgen from March 1, 2001 to...

  2. The Role of Riparian Vegetation Density, Channel Orientation and Water Velocity in Determining River Water Temperature Dynamics

    Science.gov (United States)

    Garner, G.; Malcolm, I.; Sadler, J. P.; Hannah, D. M.

    2015-12-01

    There is substantial scientific and practical interest in the potential of riparian shading to mitigate climate change impacts on river temperature extremes. However, there is limited process-based evidence to determine the density and spatial extent of riparian tree planting required to obtain temperature targets under differing environmental conditions. A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ~1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model for the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥ 1.7 °C) and maximum (≥ 3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.

  3. Water-, pH- and temperature relations of germination for the extreme xerophiles Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471).

    Science.gov (United States)

    Stevenson, Andrew; Hamill, Philip G; Dijksterhuis, Jan; Hallsworth, John E

    2017-03-01

    Water activity, temperature and pH are determinants for biotic activity of cellular systems, biosphere function and, indeed, for all life processes. This study was carried out at high concentrations of glycerol, which concurrently reduces water activity and acts as a stress protectant, to characterize the biophysical capabilities of the most extremely xerophilic organisms known. These were the fungal xerophiles: Xeromyces bisporus (FRR 0025), Aspergillus penicillioides (JH06THJ) and Eurotium halophilicum (FRR 2471). High-glycerol spores were produced and germination was determined using 38 media in the 0.995-0.637 water activity range, 33 media in the 2.80-9.80 pH range and 10 incubation temperatures, from 2 to 50°C. Water activity was modified by supplementing media with glycerol+sucrose, glycerol+NaCl and glycerol+NaCl+sucrose which are known to be biologically permissive for X. bisporus, A. penicillioides and E. halophilicum respectively. The windows and rates for spore germination were quantified for water activity, pH and temperature; symmetry/asymmetry of the germination profiles were then determined in relation to supra- and sub-optimal conditions; and pH- and temperature optima for extreme xerophilicity were quantified. The windows for spore germination were ~1 to 0.637 water activity, pH 2.80-9.80 and > 10 and < 44°C, depending on strain. Germination profiles in relation to water activity and temperature were asymmetrical because conditions known to entropically disorder cellular macromolecules, i.e. supra-optimal water activity and high temperatures, were severely inhibitory. Implications of these processes were considered in relation to the in-situ ecology of extreme conditions and environments; the study also raises a number of unanswered questions which suggest the need for new lines of experimentation. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  4. Control of matric water potential by temperature differential

    Science.gov (United States)

    Palmer, R. J. Jr; Nienow, J. A.; Friedmann, E. I.

    1987-01-01

    A method for controlling relative humidity based on temperature differentials, rather than on salt solutions, is described. This method has the following advantages: (1) it does not exhibit the anomalous CO2 solution effects that we have found to occur with salt solutions; (2) humidity is continuously adjustable without sample removal; (3) circulation of the atmosphere results in short equilibration times.

  5. Possible effects of regulating hydroponic water temperature on plant ...

    African Journals Online (AJOL)

    This may include accumulation of different metabolites such as phenolic compounds, reactive oxygen species (ROS), nutrient uptake, chlorophyll pigment formation, the photosynthesis process and finally the growth and development of the plant. The optimum temperature of the growth medium can contribute to improving ...

  6. The effect of water temperature on air entrainment, bubble plumes, and surface foam in a laboratory breaking-wave analog

    Science.gov (United States)

    Callaghan, A. H.; Stokes, M. D.; Deane, G. B.

    2014-11-01

    Air-entraining breaking waves form oceanic whitecaps and play a key role in climate regulation through air-sea bubble-mediated gas transfer, and sea spray aerosol production. The effect of varying sea surface temperature on air entrainment, subsurface bubble plume dynamics, and surface foam evolution intrinsic to oceanic whitecaps has not been well studied. By using a breaking wave analog in the laboratory over a range of water temperatures (Tw = 5°C to Tw = 30°C) and different source waters, we have examined changes in air entrainment, subsurface bubble plumes, and surface foam evolution over the course of a breaking event. For filtered seawater, air entrainment was estimated to increase by 6% between Tw = 6°C and Tw = 30°C, driven by increases of about 43% in the measured surface roughness of the plunging water sheet. After active air entrainment, the rate of loss of air through bubble degassing was more rapid at colder water temperatures within the first 0.5 s of plume evolution. Thereafter, the trend reversed and bubbles degassed more quickly in warmer water. The largest observed temperature-dependent differences in subsurface bubble distributions occurred at radii greater than about 700 μm. Temperature-dependent trends observed in the subsurface bubble plume were mirrored in the temporal evolution of the surface whitecap foam area demonstrating the intrinsic link between surface whitecap foam and the subsurface bubble plume. Differences in foam and plume characteristics due to different water sources were greater than the temperature dependencies for the filtered seawater examined.

  7. THERMODYNAMIC CONSIDERATIONS FOR THERMAL WATER SPLITTING PROCESSES AND HIGH TEMPERATURE ELECTROLYSIS

    Energy Technology Data Exchange (ETDEWEB)

    J. E. O' Brien

    2008-11-01

    A general thermodynamic analysis of hydrogen production based on thermal water splitting processes is presented. Results of the analysis show that the overall efficiency of any thermal water splitting process operating between two temperature limits is proportional to the Carnot efficiency. Implications of thermodynamic efficiency limits and the impacts of loss mechanisms and operating conditions are discussed as they pertain specifically to hydrogen production based on high-temperature electrolysis. Overall system performance predictions are also presented for high-temperature electrolysis plants powered by three different advanced nuclear reactor types, over their respective operating temperature ranges.

  8. Fungal evaluation on green tea irradiated with different water activities

    Energy Technology Data Exchange (ETDEWEB)

    Fanaro, Gustavo B.; Duarte, Renato C.; Rodrigues, Flavio T.; Villavicencio, Anna Lucia C.H., E-mail: gbfanaro@ipen.b, E-mail: villavic@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CTR/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes; Correa, Benedito, E-mail: correabe@usp.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Ciencias Biologicas. Dept. de Micologia

    2011-07-01

    The aim of this study was evaluate the fungal contamination in green tea irradiated with different radiation doses and water activities. Samples were irradiated in {sup 60}Co irradiator at doses of 0, 2.5, 5.0, 7.5 and 10.0kGy with three different water activities. In the sample with decreased water activity, the count of fungi was lower than others samples followed by original Aw and the samples with the higher water activity, however there is no difference between the increased and decreased water activities samples after the irradiation on fungi contamination at dose of 2.5 kGy. (author)

  9. Temperatures and Water Levels at Tanana Flats Monitoring Stations

    Science.gov (United States)

    2008-04-01

    a Druck pressure trans- ducer near the bottom. In response to this drawdown, the initial record showed a water level of 1.13 m on 1 April 2005, which...gradually increased to 1.68 m on 8 April. Freezing of the sensor on 9–10 April ended the reli- able water level record. A pair of replacement Drucks ...again, and a new Druck was installed to replace those that had been frozen. With rising tem- peratures at the bottom of the well, an injection of 400 g

  10. Nebulized water cooling of the canopy affects leaf temperature, berry composition and wine quality of Sauvignon blanc.

    Science.gov (United States)

    Paciello, Pericle; Mencarelli, Fabio; Palliotti, Alberto; Ceccantoni, Brunella; Thibon, Cécile; Darriet, Philippe; Pasquini, Massimiliano; Bellincontro, Andrea

    2017-03-01

    The present paper details a new technique based on spraying nebulized water on vine canopy to counteract the negative impact of the current wave of hot summers with temperatures above 30 °C, which usually determine negative effects on vine yield, grape composition and wine quality. The automatized spraying system was able to maintain air temperature at below 30 °C (the threshold temperature to start spraying) for all of August 2013, when in the canopy of uncooled vines the temperature was as high as 36 °C. The maintenance of temperature below 30 °C reduced leaf stress linked to high temperature and irradiance regimes as highlighted by the decrease of H2 O2 content and catalase activity in the leaves. A higher amount of total polyphenols and organic acids and lower sugars characterized the grapes of cooled vines. Wine from these grapes had a higher content of some volatile thiols like 3-sulfanylhexanol (3SH) and 3-sulfanylhexylacetate (3SHA), and lower content of 4-methyl-4-sulfanylpentan-2-one (4MSP). Under conditions of high temperature and irradiance regimes, water nebulization on the vine canopy can represent a valid solution to reduce and/or avoid oxidative stress and associated effects in the leaves, ensure a regular berry ripening and maintain high wine quality. The consumption of water during nebulization was acceptable, being 180 L ha(-1) min(-1) , which lasted an average of about 1 min to reduce the temperature below the threshold value of 30 °C. A total of 85-90 hL (from 0.8 to 0.9 mm) of water per hectare per day was required. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  11. Temperature Dependence of Fraction of Frozen Water in Solutions of Glucose and its Oligomers, Dextrans, and Potato Starch

    National Research Council Canada - National Science Library

    PRADIPASENA, Pasawadee; TATTIAKUL, Jirarat; NAKAMURA, Keiko; MIYAWAKI, Osato

    2007-01-01

    Initial freezing point and freezable water fraction, as the two parameters to determine the temperature dependence of fraction of frozen water, were measured systematically for solutions of glucose...

  12. EFFECTS OF PRESSURE AND TEMPERATURE ON ULTRAFILTRATION HOLLOW FIBER MEMBRANE IN MOBILE WATER TREATMENT SYSTEM

    Directory of Open Access Journals (Sweden)

    ROSDIANAH RAMLI

    2016-07-01

    Full Text Available In Sabah, Malaysia, there are still high probability of limited clean water access in rural area and disaster site. Few villages had been affected in Pitas due to improper road access, thus building a water treatment plant there might not be feasible. Recently, Kundasang area had been affected by earthquake that caused water disruption to its people due to the damage in the underground pipes and water tanks. It has been known that membrane technology brought ease in making mobile water treatment system that can be transported to rural or disaster area. In this study, hollow fiber membrane used in a mobile water treatment system due to compact and ease setup. Hollow fiber membrane was fabricated into small module at 15 and 30 fibers to suit the mobile water treatment system for potable water production of at least 80 L/day per operation. The effects of transmembrane pressure (TMP and feed water temperature were investigated. It was found that permeate flux increases by more than 96% for both 15 and 30 fiber bundles with increasing pressure in the range of 0.25 to 3.0 bar but dropped when the pressure reached maximum. Lower temperature of 17 to 18˚C increase the water viscosity by 15% from normal temperature of water at 24˚C, making the permeate flux decreases. The fabricated modules effectively removed 96% turbidity of the surface water sample tested.

  13. Review of Suction Water Content Relationship of Bentonite-Sand Mixtures Considering Temperature Effects

    Science.gov (United States)

    Rawat, Abhishek; Zhi Lang, Lin; Baille, Wiebke

    2015-04-01

    Bentonite-sand mixture is one of the candidate sealing/ buffer material for landfills, hazardous and high level radioactive waste repository. The long term satisfactory performance of bentonite sand mixture in terms of load bearing function, sealing function and buffer function is governed by hydro-mechanical response of material under elevated temperature conditions. The suction-water content relationship is one of the key parameter, which govern the thermo-hydro-mechanical behavior of compacted bentonite-sand mixture. This paper presents brief review of suction water content relationships of bentonite-sand mixture considering temperature effects. Numerous parametric models or equations have been developed for representing the soil water characteristics curve i.e. SWCC for isothermal conditions. The most frequently used equations for representing the SWCC are the van Genuchten (1980) and Fredlund and Xing (1994) SWCC equations. Various researchers (Romero et al. 2000; Villar and Lloret, 2004; Tang and Cui, 2005; Agus, 2005; Arifin, 2008) have reported the temperature effect on the water retention behavior of compacted bentonite-sand mixtures. The testing program, results and major conclusions made by above mentioned researchers were discussed in this paper. The changes in hydro-mechanical behavior due to elevated temperature are also discussed based on the suction components of soil which are influenced by temperature. As a general conclusion, total suction of the bentonite-sand mixtures is a function of mixture water content and mixture bentonite content or collectively a function of bentonite water content both at room temperature and at elevated temperature. At a constant temperature, different techniques for measuring suction results in different values of suction depending on accuracy of the sensor and calibration technique used as founded earlier by Agus (2005). The change in total suction due to change in temperature lower than 100 degree C is reversible

  14. Strategies to increase the stability of intermediate moisture foods towards Zygosaccharomyces rouxii: The effect of temperature, ethanol, pH and water activity, with or without the influence of organic acids

    DEFF Research Database (Denmark)

    Vermeulen, A.; Nielsen, Cecilie Lykke Marvig; Daelman, J.

    2015-01-01

    models for Z. rouxii, developed by Vermeulen et al. (2012) were further extended by incorporating the factor temperature. Three different data sets were build: (i) without organic acids, (ii) with acetic acid (10,000 ppm on product basis) and (iii) with sorbic acid (1500 ppm on product basis). For each......, acetic acid had only an additive effect to ethanol and aw at low pH, whereas sorbic acid had also an additive effect at the higher pH values. For incubation periods longer than 30 days the growth/no growth boundary remained stable but enlarged gradually between day 60 and 90, except for the lower......Intermediate moisture foods (IMF) are in general microbiologically stable products. However, due to health concerns consumer demands are increasingly forcing producers to lower the fat, sugar and preservatives content, which impede the stability of the IMF products. One of the strategies...

  15. Average Potential Temperature of the Upper Mantle and Excess Temperatures Beneath Regions of Active Upwelling

    Science.gov (United States)

    Putirka, K. D.

    2006-05-01

    The question as to whether any particular oceanic island is the result of a thermal mantle plume, is a question of whether volcanism is the result of passive upwelling, as at mid-ocean ridges, or active upwelling, driven by thermally buoyant material. When upwelling is passive, mantle temperatures reflect average or ambient upper mantle values. In contrast, sites of thermally driven active upwellings will have elevated (or excess) mantle temperatures, driven by some source of excess heat. Skeptics of the plume hypothesis suggest that the maximum temperatures at ocean islands are similar to maximum temperatures at mid-ocean ridges (Anderson, 2000; Green et al., 2001). Olivine-liquid thermometry, when applied to Hawaii, Iceland, and global MORB, belie this hypothesis. Olivine-liquid equilibria provide the most accurate means of estimating mantle temperatures, which are highly sensitive to the forsterite (Fo) contents of olivines, and the FeO content of coexisting liquids. Their application shows that mantle temperatures in the MORB source region are less than temperatures at both Hawaii and Iceland. The Siqueiros Transform may provide the most precise estimate of TpMORB because high MgO glass compositions there have been affected only by olivine fractionation, so primitive FeOliq is known; olivine thermometry yields TpSiqueiros = 1430 ±59°C. A global database of 22,000 MORB show that most MORB have slightly higher FeOliq than at Siqueiros, which translates to higher calculated mantle potential temperatures. If the values for Fomax (= 91.5) and KD (Fe-Mg)ol-liq (= 0.29) at Siqueiros apply globally, then upper mantle Tp is closer to 1485 ± 59°C. Averaging this global estimate with that recovered at Siqueiros yields TpMORB = 1458 ± 78°C, which is used to calculate plume excess temperatures, Te. The estimate for TpMORB defines the convective mantle geotherm, and is consistent with estimates from sea floor bathymetry and heat flow (Stein and Stein, 1992), and

  16. Temperature-Induced, Selective Assembly of Supramolecular Colloids in Water

    NARCIS (Netherlands)

    Van Ravensteijn, Bas G.P.; Vilanova, Neus; De Feijter, Isja; Kegel, Willem K.; Voets, Ilja K.

    2017-01-01

    In this article, we report the synthesis and physical characterization of colloidal polystyrene particles that carry water-soluble supramolecular N,N′,N″,-trialkyl-benzene-1,3,5-tricarboxamides (BTAs) on their surface. These molecules are known to assemble into one-dimensional supramolecular

  17. Effects of temperature and water stresses on germination of some ...

    African Journals Online (AJOL)

    Insaf

    2013-04-24

    Apr 24, 2013 ... species. Acta Oecol. 23:23-30. Singh F, Diwakar B (1995). Chickpea botany and production practices. Skill Development Series N°16. ICRISAT. Smita KJ, Nayyar H (2005). Carbendazim alleviates effects of water stress on chickpea seedlings. Biol. Plant. 49:289-291. Tejera NA, Soussi M, Lluch C (2006).

  18. Temperature effects in deep-water hydrate foam

    CERN Document Server

    Egorov, Alexander V; Rozhkov, Aleksey N

    2016-01-01

    This study focuses on heat and mass exchange processes in hydrate foam during its formation from methane bubbles in gas hydrate stability zone (GHSZ) of the Lake Baikal and following delivery of it in open container to the lake surface. The foam was formed as a result of methane bubble collection with a trap/container. The trap was inverted glass beaker of diameter of 70 mm and 360 mm long. Open bottom end of the beaker used as enter for bubbles ascended from the lakebed. At a depth of 1400 m all bubbles which fed to the trap were transformed here into solid hydrate foam. The sensitive thermometer was mounted in the middle of the trap and recorded the temperature inside trap. The fate of the bubbles in the trap was recorded by video-camera. During ascend within GHSZ with velocity of about 0.375 m/s we observed the continuous decrease of the temperature in the foam up to a level of negative magnitude in a depth interval of 1400 - 750 meters. Above 750 m temperature decrease was changed by small growth. However...

  19. 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.

  20. Compensatory water effects link yearly global land CO2 sink changes to temperature

    Science.gov (United States)

    Jung, Martin; Reichstein, Markus; Schwalm, Christopher R.; Huntingford, Chris; Sitch, Stephen; Ahlström, Anders; Arneth, Almut; Camps-Valls, Gustau; Ciais, Philippe; Friedlingstein, Pierre; Gans, Fabian; Ichii, Kazuhito; Jain, Atul K.; Kato, Etsushi; Papale, Dario; Poulter, Ben; Raduly, Botond; Rödenbeck, Christian; Tramontana, Gianluca; Viovy, Nicolas; Wang, Ying-Ping; Weber, Ulrich; Zaehle, Sönke; Zeng, Ning

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales. Here we use empirical models based on eddy covariance data and process-based models to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  1. Compensatory Water Effects Link Yearly Global Land CO2 Sink Changes to Temperature

    Science.gov (United States)

    Jung, Martin; Reichstein, Markus; Tramontana, Gianluca; Viovy, Nicolas; Schwalm, Christopher R.; Wang, Ying-Ping; Weber, Ulrich; Weber, Ulrich; Zaehle, Soenke; Zeng, Ning; hide

    2017-01-01

    Large interannual variations in the measured growth rate of atmospheric carbon dioxide (CO2) originate primarily from fluctuations in carbon uptake by land ecosystems13. It remains uncertain, however, to what extent temperature and water availability control the carbon balance of land ecosystems across spatial and temporal scales314. Here we use empirical models based on eddy covariance data15 and process-based models16,17 to investigate the effect of changes in temperature and water availability on gross primary productivity (GPP), terrestrial ecosystem respiration (TER) and net ecosystem exchange (NEE) at local and global scales. We find that water availability is the dominant driver of the local interannual variability in GPP and TER. To a lesser extent this is true also for NEE at the local scale, but when integrated globally, temporal NEE variability is mostly driven by temperature fluctuations. We suggest that this apparent paradox can be explained by two compensatory water effects. Temporal water-driven GPP and TER variations compensate locally, dampening water-driven NEE variability. Spatial water availability anomalies also compensate, leaving a dominant temperature signal in the year-to-year fluctuations of the land carbon sink. These findings help to reconcile seemingly contradictory reports regarding the importance of temperature and water in controlling the interannual variability of the terrestrial carbon balance36,9,11,12,14. Our study indicates that spatial climate covariation drives the global carbon cycle response.

  2. Rainfall simulation experiments: Influence of water temperature, water quality and plot design on soil erosion and runoff

    Science.gov (United States)

    Iserloh, Thomas; Pegoraro, Dominique; Schlösser, Angelika; Thesing, Hannah; Seeger, Manuel; Ries, Johannes B.

    2015-04-01

    Field rainfall simulators are designed to study soil erosion processes and provide urgently needed data for various geomorphological, hydrological and pedological issues. Due to the different conditions and technologies applied, there are several methodological aspects under review of the scientific community, particularly concerning design, procedures and conditions of measurement for infiltration, runoff and soil erosion. This study aims at contributing fundamental data for understanding rainfall simulations in depth by studying the effect of the following parameters on the measurement results: 1. Plot design - round or rectangular plot: Can we identify differences in amount of runoff and erosion? 2. Water quality: What is the influence of the water's salt load on interrill erosion and infiltration as measured by rainfall experiments? 3. Water temperature: How much are the results conditioned by the temperature of water, which is subject to changes due to environmental conditions during the experiments? Preliminary results show a moderate increase of soil erosion with the water's salt load while runoff stays almost on the same level. With increasing water temperature, runoff increases continuously. At very high temperatures, soil erosion is clearly increased. A first comparison between round and rectangular plot indicates the rectangular plot to be the most suitable plot shape, but ambiguous results make further research necessary. The analysis of these three factors concerning their influence on runoff and erosion shows that clear methodological standards are necessary in order to make rainfall simulation experiments comparable.

  3. The nature of supply side effects on electricity prices: the impact of water temperature

    NARCIS (Netherlands)

    Boogert, Alexander; Dupont, D.Y.

    2005-01-01

    In this paper, we show that the impact of water temperatures on electricity prices observed in Europe in summer 2003 has prevailed for years. We trace its source to technological and regulatory constraints and draw lessons for modelling.

  4. Nimbus-6/SCAMS Level 2 Water Vapor and Temperature V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nimbus-6 Scanning Microwave Spectrometer (SCAMS) Level 2 data product contains water vapor and temperature profiles. The SCAMS was designed to map tropospheric...

  5. Gulf of Maine - Water Salinity, Temperature and Sigma t (density) data from 1912 to 1930

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This table contains water salinity, temperature and sigma t (density) data from 1912 to 1930 binned at 10 meter depth intervals (from 300 meters up to 0 meters) for...

  6. Gulf of Maine - Water Salinity, Temperature and Sigma t (density) data from 1981 to 2005

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This table contains water salinity, temperature and sigma t (density) data from 1981 to 2005 binned at 10 meter depth intervals (from 300 meters up to 0 meters) for...

  7. Gulf of Maine - Water Salinity, Temperature and Sigma t (density) data from 1956 to 1980

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This table contains water salinity, temperature and sigma t (density) data from 1956 to 1980 binned at 10 meter depth intervals (from 300 meters up to 0 meters) for...

  8. STRATOSPHERIC TEMPERATURES AND WATER LOSS FROM MOIST GREENHOUSE ATMOSPHERES OF EARTH-LIKE PLANETS

    Energy Technology Data Exchange (ETDEWEB)

    Kasting, James F.; Kopparapu, Ravi K. [Department of Geosciences, The Pennsylvania State University, State College, PA 16801 (United States); Chen, Howard, E-mail: jfk4@psu.edu, E-mail: hwchen@bu.edu [Department of Astronomy, Boston University, 725 Commonwealth Ave., Boston, MA 02215 (United States)

    2015-11-01

    A radiative-convective climate model is used to calculate stratospheric temperatures and water vapor concentrations for ozone-free atmospheres warmer than that of modern Earth. Cold, dry stratospheres are predicted at low surface temperatures, in agreement with recent 3D calculations. However, at surface temperatures above 350 K, the stratosphere warms and water vapor becomes a major upper atmospheric constituent, allowing water to be lost by photodissociation and hydrogen escape. Hence, a moist greenhouse explanation for loss of water from Venus, or some exoplanet receiving a comparable amount of stellar radiation, remains a viable hypothesis. Temperatures in the upper parts of such atmospheres are well below those estimated for a gray atmosphere, and this factor should be taken into account when performing inverse climate calculations to determine habitable zone boundaries using 1D models.

  9. Gulf of Maine - Water Salinity, Temperature and Sigma t (density) data from 1931 to 1955

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This table contains water salinity, temperature and sigma t (density) data from 1931 to 1955 binned at 10 meter depth intervals (from 300 meters up to 0 meters) for...

  10. The Effect of Water Temperature on Argulus foliaceus L. 1758 (Crustacea; Branchiura on Different Fish Species

    Directory of Open Access Journals (Sweden)

    Mustafa KOYUN

    2011-05-01

    Full Text Available Parasites belonging to Argulus genus, known as fish louse (Argulus foliaceus L. significantly affect in negative way both in natural and farming environment. In this study, the pathogenic effect of fish louse temperature on fish depending on water was investigated. In this research to estimate the effects of several factors such as water temperature, gender of the fish and the infection of fish louse were studied through Poisson regression method. As fish species, Alburnus alburnus (bleak, Carassius carassius (crucian carp and Carassius auratus (golden carp were caught periodically, starting from May during the year, and the parasites were counted. The gender and metrical measures of the examined fish were categorized separately. The degrees of water temperature of the dam were measured. Results from Poisson regression analysis showed that fish louse has harmful effect on the mentioned fish, depending on the water temperature.

  11. Solubility of zinc ferrite in high-temperature oxygenated water

    Science.gov (United States)

    Hanzawa, Yukiko; Hiroishi, Daisuke; Matsuura, Chihiro; Ishigure, Kenkichi

    1998-02-01

    The solubility of zinc ferrite was measured at 423 K, 473 K, and 523 K in an oxygenated water system, which is rather similar to the chemical condition of boiling water reactors. Thermodynamic analysis was performed by a procedure minimizing standard Gibbs free energy of the system at the final state. From both the analysis and the experimental results it was concluded that the dissolution process of ZnFe 2O 4 in conditions where no redox reaction occurs is described by combination of ZnFe 2O 4 dissolution and Fe 2O 3 precipitation equilibria. By fitting to the experimental results, thermodynamic data of ZnFe 2O 4 are re-analyzed at 423 K, 473 K, and 523 K.

  12. Water and sediment temperatures at mussel beds in the upper Mississippi River basin

    Science.gov (United States)

    Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

    2013-01-01

    Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

  13. A hierarchical model of daily stream temperature using air-water temperature synchronization, autocorrelation, and time lags

    Science.gov (United States)

    Letcher, Benjamin; Hocking, Daniel; O'Neil, Kyle; Whiteley, Andrew R.; Nislow, Keith H.; O'Donnell, Matthew

    2016-01-01

    Water temperature is a primary driver of stream ecosystems and commonly forms the basis of stream classifications. Robust models of stream temperature are critical as the climate changes, but estimating daily stream temperature poses several important challenges. We developed a statistical model that accounts for many challenges that can make stream temperature estimation difficult. Our model identifies the yearly period when air and water temperature are synchronized, accommodates hysteresis, incorporates time lags, deals with missing data and autocorrelation and can include external drivers. In a small stream network, the model performed well (RMSE = 0.59°C), identified a clear warming trend (0.63 °C decade−1) and a widening of the synchronized period (29 d decade−1). We also carefully evaluated how missing data influenced predictions. Missing data within a year had a small effect on performance (∼0.05% average drop in RMSE with 10% fewer days with data). Missing all data for a year decreased performance (∼0.6 °C jump in RMSE), but this decrease was moderated when data were available from other streams in the network.

  14. Coupled daily streamflow and water temperature modelling in large river basins

    Directory of Open Access Journals (Sweden)

    M. T. H. van Vliet

    2012-11-01

    Full Text Available Realistic estimates of daily streamflow and water temperature are required for effective management of water resources (e.g. for electricity and drinking water production and freshwater ecosystems. Although hydrological and process-based water temperature modelling approaches have been successfully applied to small catchments and short time periods, much less work has been done at large spatial and temporal scales. We present a physically based modelling framework for daily river discharge and water temperature simulations applicable to large river systems on a global scale. Model performance was tested globally at 1/2 × 1/2° spatial resolution and a daily time step for the period 1971–2000. We made specific evaluations on large river basins situated in different hydro-climatic zones and characterized by different anthropogenic impacts. Effects of anthropogenic heat discharges on simulated water temperatures were incorporated by using global gridded thermoelectric water use datasets and representing thermal discharges as point sources into the heat advection equation. This resulted in a significant increase in the quality of the water temperature simulations for thermally polluted basins (Rhine, Meuse, Danube and Mississippi. Due to large reservoirs in the Columbia which affect streamflow and thermal regimes, a reservoir routing model was used. This resulted in a significant improvement in the performance of the river discharge and water temperature modelling. Overall, realistic estimates were obtained at daily time step for both river discharge (median normalized BIAS = 0.3; normalized RMSE = 1.2; r = 0.76 and water temperature (median BIAS = −0.3 °C; RMSE = 2.8 °C; r = 0.91 for the entire validation period, with similar performance during warm, dry periods. Simulated water temperatures are sensitive to headwater temperature, depending on resolution and flow velocity. A high sensitivity of water temperature to river

  15. Dissolved oxygen, stream temperature, and fish habitat response to environmental water purchases.

    Science.gov (United States)

    Null, Sarah E; Mouzon, Nathaniel R; Elmore, Logan R

    2017-07-15

    Environmental water purchases are increasingly used for ecological protection. In Nevada's Walker Basin (western USA), environmental water purchases augment streamflow in the Walker River and increase lake elevation of terminal Walker Lake. However, water quality impairments like elevated stream temperatures and low dissolved oxygen concentrations also limit ecosystems and species, including federally-threatened Lahontan cutthroat trout. In this paper, we prioritize water volumes and locations that most enhance water quality for riverine habitat from potential environmental water rights purchases. We monitored and modeled streamflows, stream temperatures, and dissolved oxygen concentrations using River Modeling System, an hourly, physically-based hydrodynamic and water quality model. Modeled environmental water purchases ranged from average daily increases of 0.11-1.41 cubic meters per second (m 3 /s) during 2014 and 2015, two critically dry years. Results suggest that water purchases consistently cooled maximum daily stream temperatures and warmed nightly minimum temperatures. This prevented extremely low dissolved oxygen concentrations below 5.0 mg/L, but increased the duration of moderate conditions between 5.5 and 6.0 mg/L. Small water purchases less than approximately 0.71 m 3 /s per day had little benefit for Walker River habitat. Dissolved oxygen concentrations were affected by upstream environmental conditions, where suitable upstream water quality improved downstream conditions and vice versa. Overall, this study showed that critically dry water years degrade environmental water quality and habitat, but environmental water purchases of at least 0.71 m 3 /s were promising for river restoration. Published by Elsevier Ltd.

  16. Relationships between secchi disk visibility, water temperature and dissolved oxygen in freshwater fishpond

    OpenAIRE

    Ali, M.H.; Cagauan, A.G.

    2007-01-01

    A study was conducted to determine the relationships between secchi disk variability, water temperature and dissolved oxygen in fish ponds. Multiple regression correlation analysis was done to evaluate the relationships between the variables. Results indicated that the ranges of secchi disk visibility, water temperature and dissolved oxygen in the study ponds were just within the ranges of the variables for tilapia culture. Multiple regression correlation showed no (or insignificant) relation...

  17. Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features

    OpenAIRE

    Luoto, Tomi; Nevalainen, Liisa

    2013-01-01

    Long-term water temperature records are necessary for better understanding climate change impacts on freshwaters. We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses to regional climate variability since the Little Ice Age. Our results indicate divergent trends for the lakes. In two of the lakes, which are located at the sunny southern slope of mou...

  18. Lateralized Difference in Tympanic Membrane Temperature: Emotion and Hemispheric Activity

    Directory of Open Access Journals (Sweden)

    Ruth E Propper

    2013-03-01

    Full Text Available We review literature examining relationships between tympanic membrane temperature (TMT, affective/motivational orientation, and hemispheric activity. Lateralized differences in TMT might enable real-time monitoring of hemispheric activity in real-world conditions, and could serve as a corroborating marker of mental illnesses associated with specific affective dysregulation. We support the proposal that TMT holds potential for broadly indexing lateralized brain physiology during tasks demanding the processing and representation of emotional and/or motivational states, and for predicting trait-related affective/motivational orientations. The precise nature of the relationship between TMT and brain physiology, however, remains elusive. Indeed the limited extant research has sampled different participant populations and employed largely different procedures and measures, making for seemingly discrepant findings and implications. We propose, however, that many of these discrepancies can be resolved by considering how emotional states map onto motivational systems, and further examining how validated methods for inducing lateralized brain activity might affect TMT.

  19. Army Corps of Engineers: Water Resource Authorizations, Appropriations, and Activities

    Science.gov (United States)

    2017-02-27

    Army Corps of Engineers: Water Resource Authorizations, Appropriations, and Activities Nicole T. Carter Specialist in Natural Resources Policy...of Engineers: Water Resource Authorizations, Appropriations, and Activities Congressional Research Service Summary The U.S. Army Corps of...congressional attention because its water resource projects can have significant local and regional economic benefits and environmental effects

  20. Water temperature, voluntary drinking and fluid balance in dehydrated taekwondo athletes.

    Science.gov (United States)

    Khamnei, Saeed; Hosseinlou, Abdollah; Zamanlu, Masumeh

    2011-01-01

    Voluntary drinking is one of the major determiners of rehydration, especially as regards exercise or workout in the heat. The present study undertakes to search for the effect of voluntary intake of water with different temperatures on fluid balance in Taekwondo athletes. Six young healthy male Taekwondo athletes were dehydrated by moderate exercise in a chamber with ambient temperature at 38-40°C and relative humidity between 20-30%. On four separate days they were allowed to drink ad libitum plane water with the four temperatures of 5, 16, 26, and 58°C, after dehydration. The volume of voluntary drinking and weight change was measured; then the primary percentage of dehydration, sweat loss, fluid deficit and involuntary dehydration were calculated. Voluntary drinking of water proved to be statistically different in the presented temperatures. Water at 16°C involved the greatest intake, while fluid deficit and involuntary dehydration were the lowest. Intake of water in the 5°C trial significantly correlated with the subject's plasma osmolality change after dehydration, yet it showed no significant correlation with weight loss. In conclusion, by way of achieving more voluntary intake of water and better fluid state, recommending cool water (~16°C) for athletes is in order. Unlike the publicly held view, drinking cold water (~5°C) does not improve voluntary drinking and hydration status. Key pointsFor athletes dehydrated in hot environments, maximum voluntary drinking and best hydration state occurs with 16°C water.Provision of fluid needs and thermal needs could be balanced using 16°C water.Drinking 16°C water (nearly the temperature of cool tap water) could be recommended for exercise in the heat.

  1. Removal of nitrate from water by adsorption onto zinc chloride treated activated carbon

    DEFF Research Database (Denmark)

    Bhatnagar, A.; Ji, M.; Choi, Y.H.

    2008-01-01

    Adsorption study with untreated and zinc chloride (ZnCl2) treated coconut granular activated carbon (GAC) for nitrate removal from water has been carried out. Untreated coconut GAC was treated with ZnCl2 and carbonized. The optimal conditions were selected by studying the influence of process...... variables such as chemical ratio and activation temperature. Experimental results reveal that chemical weight ratio of 200% and temperature of 500 degrees C was found to be optimum for the maximum removal of nitrate from water. Both untreated and ZnCl2 treated coconut GACs were characterized by scanning...

  2. Active Wireless Temperature Sensors for Aerospace Thermal Protection Systems

    Science.gov (United States)

    Milos, Frank S.; Karunaratne, K.; Arnold, Jim (Technical Monitor)

    2002-01-01

    Health diagnostics is an area where major improvements have been identified for potential implementation into the design of new reusable launch vehicles in order to reduce life-cycle costs, to increase safety margins, and to improve mission reliability. NASA Ames is leading the effort to advance inspection and health management technologies for thermal protection systems. This paper summarizes a joint project between NASA Ames and Korteks to develop active wireless sensors that can be embedded in the thermal protection system to monitor sub-surface temperature histories. These devices are thermocouples integrated with radio-frequency identification circuitry to enable acquisition and non-contact communication of temperature data through aerospace thermal protection materials. Two generations of prototype sensors are discussed. The advanced prototype collects data from three type-k thermocouples attached to a 2.54-cm square integrated circuit.

  3. EFFECT OF WATER CONTENT, TEMPERATURE AND AVERAGE DROPLET SIZE ON THE SETTLING VELOCITY OF WATER-IN-OIL EMULSIONS

    Directory of Open Access Journals (Sweden)

    W. J. Souza

    2015-06-01

    Full Text Available AbstractWater-in-oil (W/O emulsions are complex mixtures generally found in crude oil production in reservoirs and processing equipment. Sedimentation studies of water-oil emulsions enable the analysis of the fluid dynamic behavior concerning separation of this system composed of two immiscible liquids. Gravitational settling was evaluated in this article for a model emulsion system consisting of water and a Brazilian crude oil diluted in a clear mineral oil as organic phase. The effects of water content and temperature were considered in the study of sedimentation velocity of water-oil emulsions. Water contents between 10% and 50 % and temperatures of 25, 40 and 60 ºC were evaluated, and a Richardson-Zaki type correlation was obtained to calculate settling velocities as a function of the process variables investigated. Water contents and average droplet sizes were monitored at different levels in the settling equipment, thus enabling identification of the effect of these variables on the phenomena of sedimentation and coalescence of the emulsions studied. The results showed that the emulsion stability during sedimentation was governed by the emulsion water content, which yielded high settling velocities at low water contents, even when very small droplets were present. A quantitative analysis of the combined effects of drop size and droplet concentration supports the conclusion that a stronger effect is produced by the higher concentration of particles, compared with the relatively smaller effect of increasing the size of the droplets.

  4. Climate-induced changes in river water temperature in North Iberian Peninsula

    Science.gov (United States)

    Soto, Benedicto

    2017-06-01

    This study evaluates the effects of climate change on the thermal regime of 12 rivers in the Northern Iberian Peninsula by using a non-linear regression model that employs air temperature as the only input variable. Prediction of future air temperature was obtained from five regional climate models (RCMs) under emission scenario Special Report on Emissions Scenarios A1B. Prior to simulation of water temperature, air temperature was bias-corrected (B-C) by means of variance scaling (VS) method. This procedure allows an improvement of fit between observed and estimated air temperature for all climate models. The simulation of water temperature for the period 1990-2100 shows an increasing trend, which is higher for the period of June-August (summer) and September-November (autumn) (0.0275 and 0.0281 °C/year) than that of winter (December-February) and spring (March-May) (0.0181 and 0.0218 °C/year). In the high air temperature range, daily water temperature is projected to increase on average by 2.2-3.1 °C for 2061-2090 relative to 1961-1990. During the coldest days, the increment of water temperature would range between 1.0 and 1.7 °C. In fact, employing the numbers of days that water temperature exceeded the upper incipient lethal temperature (UILT) for brown trout (24.7 °C) has been noted that this threshold is exceeded 14.5 days per year in 2061-2090 while in 1961-1990, this values was exceeded 2.6 days per year of mean and 3.6 days per year in observation period (2000-2014).

  5. Hiatus in global warming - example of water temperature of the Danube River at Bogojevo gauge (Serbia

    Directory of Open Access Journals (Sweden)

    Ducić Vladan

    2015-01-01

    Full Text Available The research included trends in water temperature of the Danube River at Bogojevo gauge and surface air temperature at the nearby meteorological station Sombor, as well as an analysis of the results obtained in relation to the claims of the existence of the hiatus in global air temperature increase in the period 1998-2012. In the period 1961-2013, there was a statistically significant increase in the mean annual water temperature (0.039°C/year, as well as all the average monthly values. However, with annual values for the period 1998-2013, there was a decrease. The longest periods of negative trend (27 years were recorded for January and February. A high correlation was found between the surface air temperature and water temperature for all monthly and seasonal values. In the mean annual air temperature the presence of the hiatus is not observed, but a negative trend is recorded in March (32 years, December (43 years and February (49 years. The highest correlations between water temperature and North Atlantic Oscillation (NAO, Arctic Oscillation (AO and Atlantic Multidecadal Oscillation (AMO were obtained for the NAO in January (0.60, the AMO in autumn (0.52 and the NAO in winter (0.51. For surface air temperature, the highest correlations were registered for the AMO in summer (0.49 and the NAO in winter (0.42. The results indicate the dominant role of natural factors in the decrease of winter air temperature and water temperature of the Danube. [Projekat Ministarstva nauke Republike Srbije, br. III47007

  6. The role of riparian vegetation density, channel orientation and water velocity in determining river temperature dynamics

    Science.gov (United States)

    Garner, Grace; Malcolm, Iain A.; Sadler, Jonathan P.; Hannah, David M.

    2017-10-01

    A simulation experiment was used to understand the importance of riparian vegetation density, channel orientation and flow velocity for stream energy budgets and river temperature dynamics. Water temperature and meteorological observations were obtained in addition to hemispherical photographs along a ∼1 km reach of the Girnock Burn, a tributary of the Aberdeenshire Dee, Scotland. Data from nine hemispherical images (representing different uniform canopy density scenarios) were used to parameterise a deterministic net radiation model and simulate radiative fluxes. For each vegetation scenario, the effects of eight channel orientations were investigated by changing the position of north at 45° intervals in each hemispheric image. Simulated radiative fluxes and observed turbulent fluxes drove a high-resolution water temperature model of the reach. Simulations were performed under low and high water velocity scenarios. Both velocity scenarios yielded decreases in mean (≥1.6 °C) and maximum (≥3.0 °C) temperature as canopy density increased. Slow-flowing water resided longer within the reach, which enhanced heat accumulation and dissipation, and drove higher maximum and lower minimum temperatures. Intermediate levels of shade produced highly variable energy flux and water temperature dynamics depending on the channel orientation and thus the time of day when the channel was shaded. We demonstrate that in many reaches relatively sparse but strategically located vegetation could produce substantial reductions in maximum temperature and suggest that these criteria are used to inform future river management.

  7. Uncertainty of Wheat Water Use: Simulated Patterns and Sensitivity to Temperature and CO2

    Science.gov (United States)

    Cammarano, Davide; Roetter, Reimund P.; Asseng, Senthold; Ewert, Frank; Wallach, Daniel; Martre, Pierre; Hatfield, Jerry L.; Jones, James W.; Rosenzweig, Cynthia E.; Ruane, Alex C.; hide

    2016-01-01

    Projected global warming and population growth will reduce future water availability for agriculture. Thus, it is essential to increase the efficiency in using water to ensure crop productivity. Quantifying crop water use (WU; i.e. actual evapotranspiration) is a critical step towards this goal. Here, sixteen wheat simulation models were used to quantify sources of model uncertainty and to estimate the relative changes and variability between models for simulated WU, water use efficiency (WUE, WU per unit of grain dry mass produced), transpiration efficiency (Teff, transpiration per kg of unit of grain yield dry mass produced), grain yield, crop transpiration and soil evaporation at increased temperatures and elevated atmospheric carbon dioxide concentrations ([CO2]). The greatest uncertainty in simulating water use, potential evapotranspiration, crop transpiration and soil evaporation was due to differences in how crop transpiration was modelled and accounted for 50 of the total variability among models. The simulation results for the sensitivity to temperature indicated that crop WU will decline with increasing temperature due to reduced growing seasons. The uncertainties in simulated crop WU, and in particularly due to uncertainties in simulating crop transpiration, were greater under conditions of increased temperatures and with high temperatures in combination with elevated atmospheric [CO2] concentrations. Hence the simulation of crop WU, and in particularly crop transpiration under higher temperature, needs to be improved and evaluated with field measurements before models can be used to simulate climate change impacts on future crop water demand.

  8. Primary collector wall local temperature fluctuations in the area of water-steam phase boundary

    Energy Technology Data Exchange (ETDEWEB)

    Matal, O.; Klinga, J.; Simo, T. [Energovyzkum Ltd., Brno (Switzerland)

    1995-12-31

    A limited number of temperature sensors could be installed at the primary collector surface in the area of water - steam phase boundary. The surface temperatures as well WWER 440 steam generator process data were measured and stored for a long time and off-line evaluated. Selected results are presented in the paper. (orig.). 2 refs.

  9. Optimizing withdrawal from drinking water reservoirs to reduce downstream temperature pollution and reservoir hypoxia.

    Science.gov (United States)

    Weber, M; Rinke, K; Hipsey, M R; Boehrer, B

    2017-07-15

    Sustainable management of drinking water reservoirs requires balancing the demands of water supply whilst minimizing environmental impact. This study numerically simulates the effect of an improved withdrawal scheme designed to alleviate the temperature pollution downstream of a reservoir. The aim was to identify an optimal withdrawal strategy such that water of a desirable discharge temperature can be supplied downstream without leading to unacceptably low oxygen concentrations within the reservoir. First, we calibrated a one-dimensional numerical model for hydrodynamics and oxygen dynamics (GLM-AED2), verifying that the model reproduced water temperatures and hypolimnetic dissolved oxygen concentrations accurately over a 5 year period. Second, the model was extended to include an adaptive withdrawal functionality, allowing for a prescribed withdrawal temperature to be found, with the potential constraint of hypolimnetic oxygen concentration. Scenario simulations on epi-/metalimnetic withdrawal demonstrate that the model is able to autonomously determine the best withdrawal height depending on the thermal structure and the hypolimnetic oxygen concentration thereby optimizing the ability to supply a desirable discharge temperature to the downstream river during summer. This new withdrawal strategy also increased the hypolimnetic raw water volume to be used for drinking water supply, but reduced the dissolved oxygen concentrations in the deep and cold water layers (hypolimnion). Implications of the results for reservoir management are discussed and the numerical model is provided for operators as a simple and efficient tool for optimizing the withdrawal strategy within different reservoir contexts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Comparing temperature effects on Escherichia coli, Salmonella, and Enterococcus survival in surface waters.

    Science.gov (United States)

    Pachepsky, Y A; Blaustein, R A; Whelan, G; Shelton, D R

    2014-09-01

    The objective of this study was to compare dependency of survival rates on temperature for indicator organisms Escherichia coli and Enterococcus and the pathogen Salmonella in surface waters. A database of 86 survival datasets from peer-reviewed papers on inactivation of E. coli, Salmonella and Enterococcus in marine waters and of E. coli and Salmonella in lake waters was assembled. The Q10 model was used to express temperature effect on survival rates obtained from linear sections of semi-logarithmic survival graphs. Available data were insufficient to establish differences in survival rates and temperature dependencies for marine waters where values of Q10  = 3 and a survival rate of 0·7 day(-1) could be applied. The Q10 values in lake waters were substantially lower in marine waters, and Salmonella inactivation in lake water was, on average, twice as fast as E. coli; data on E. coli substantially outnumber data on Enterococcus and Salmonella. The relative increase in inactivation with increase in temperature is higher in marine waters than lake water, and differences in inactivation between Salmonella and E. coli at a given temperature were significant in lake water but not in marine waters. Microbiological quality of surface waters is of paramount importance for public health. The novelty of this work is using a large compendium of published data to develop the first comparison of temperature effects on survival of the pathogen Salmonella and water quality indicator micro-organisms Escherichia coli and Enterococcus in natural waters. The existing relatively large body of knowledge on E. coli survival appears to be useful to assess the effect of temperature on survival of Salmonella. Moreover, results of this work constitute an essential input in models to support environmental management decisions on the use of surface water sources in agriculture, aquaculture and recreation. © Published 2014. This article is a U.S. Government work and is in the

  11. Amphiphilic siloxane phosphonate macromolecule monolayers at the air/water interface: effects of structure and temperature.

    Science.gov (United States)

    Cabasso, Israel; Stesikova, Elvira

    2008-11-20

    A comprehensive study is reported of Langmuir-Blodgett (LB) films (spread at the air/water interface using the Langmuir balance technique) composed of surface active, nonionic, and OH-free amphiphilic siloxane phosphonate ester macromolecules. Analysis is made on three molecular structures in the form of linear polymer poly(diethylphosphono-benzyl-alphabeta-ethyl methylsiloxane) (PPEMS), cyclic oligomer methylphosphonobenzyl-alphabeta-ethyl cyclosiloxane (MPECS), and copolymer poly(PEMS-co-DMS). The surface pressure-surface area (pi -A) isotherms of homopolymer at 3-40 degrees C show a clear temperature-induced phase transition (plateaus at pit approximately 17-19 mN/m) below 10 degrees C. The magnitude of the transition substantially increases upon lowering the temperature (partial differential DeltaAt/ partial differential T approximately -0.1 nm2 unit(-1) deg(-1) and partial differential pi t / partial differential T approximately -0.25 mN m(-1) deg(-1)). The positive entropy and enthalpy gain infers that strong coupling with the subphase and excess hydration attributed to hydrogen bonding between the P=O bond and the subphase prevails at low temperatures. The cyclic oligomer MPECS forms a condensed monolayer at the air/water interface that does not display a similar transition in the experimental temperature range. The temperature sensitivity of MPECS film is observed only in the collapsed region. The nature of the interaction with the subphase is similar for MPECS and PPEMS, indicating that the size and thermal mobility are the controlling factors in these processes. The elasticity plot reveals two distinct states (above and below transition). This observation is supported by BAM images that show irregular spiral structures below 10 degrees C. The transition occurring in the copolymer at 20 degrees C is due to relaxation of the PDMS component. The two maxima shown in the elasticity plot indicate additive fractions of PPEMS and PDMS. The surface areas of these

  12. Low-Temperature Synthesis of Hierarchical Amorphous Basic Nickel Carbonate Particles for Water Oxidation Catalysis.

    Science.gov (United States)

    Yang, Yisu; Liang, Fengli; Li, Mengran; Rufford, Thomas E; Zhou, Wei; Zhu, Zhonghua

    2015-07-08

    Amorphous nickel carbonate particles are catalysts for the oxygen evolution reaction (OER), which plays a critical role in the electrochemical splitting of water. The amorphous nickel carbonate particles can be prepared at a temperature as low as 60 °C by an evaporation-induced precipitation (EIP) method. The products feature hierarchical pore structures. The mass-normalized activity of the catalysts, measured at an overpotential of 0.35 V, was 55.1 A g(-1) , with a Tafel slope of only 60 mV dec(-1) . This catalytic activity is superior to the performance of crystalline NiOx particles and β-Ni(OH)2 particles, and compares favorably to state-of-the-art RuO2 catalysts. The activity of the amorphous nickel carbonate is remarkably stable during a 10 000 s chronoamperometry test. Further optimization of synthesis parameters reveals that the amorphous structure can be tuned by adjusting the H2 O/Ni ratio in the precursor mixture. These results suggest the potential application of easily prepared hierarchical basic nickel carbonate particles as cheap and robust OER catalysts with high activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Thermodynamic Study of Water Activity of Single Strong Electrolytes

    Directory of Open Access Journals (Sweden)

    Seyed Hossein Hashemi

    2017-06-01

    Full Text Available Today, due to the natural decline of oil exploitation, the use of methods of oil recovery, has made significant progress. However, these methods are accompanied by accumulation and deposition of mineral deposits in oil field installations. In the present study, aqueous solutions, strontium sulfate, barium sulfate, manganese sulfate and nickel sulfate are studied, in terms of EUNIQUAC model and genetic algorithms. Based on the findings of this article, as temperature increases, in order to increase the solubility of the system, the ionic strength decreases; but with increasing pressure, the solubility of barium sulfate increases. Meanwhile, in this article, to evaluate water activity, aqueous solutions of manganese sulfate and nickel sulfate is studied.

  14. Evening physical activity alters wrist temperature circadian rhythmicity

    OpenAIRE

    Rubio-Sastre, Patricia; Gómez-Abellán, Purificación; Martinez-Nicolas, Antonio; Ordovás, José María; Madrid, Juan Antonio; Garaulet, Marta

    2013-01-01

    The adequate time to perform physical activity (PA) to maintain optimal circadian system health has not been defined. We studied the influence of morning and evening PA on circadian rhythmicity in 16 women with wrist temperature (WT). Participants performed controlled PA (45 min continuous-running) during 7 days in the morning (MPA) and evening (EPA) and results were compared with a no-exercise-week (C). EPA was characterized by a lower amplitude (evening: 0.028 ± 0.01 °C versus control: 0.03...

  15. Spatial Correlations of Anomalies of Tropospheric Temperature and Water Vapor, Cloud Cover, and OLR with the El Nino Index

    Science.gov (United States)

    Susskind, Joel; Iredell, Lena; Lee, Jae N.

    2014-01-01

    In this presentation, we will show AIRS Version-6 area weighted anomaly time series over the time period September 2002 through August 2014 of atmospheric temperature and water vapor profiles as a function of height. These anomaly time series show very different behaviors in the stratosphere and in the troposphere. Tropical mean stratospheric temperature anomaly time series are very strongly influenced by the Quasi-Biennial Oscillation (QBO) with large anomalies that propagate downward from 1 mb to 100 mb with a period of about two years. AIRS stratospheric temperature anomalies are in good agreement with those obtained by MLS over a common period. Tropical mean tropospheric temperature profile anomalies appear to be totally disconnected from those of the stratosphere and closely follow El Nino La Nina activity.

  16. WATER TEMPERATURE, VOLUNTARY DRINKING AND FLUID BALANCE IN DEHYDRATED TAEKWONDO ATHLETES

    Directory of Open Access Journals (Sweden)

    Saeed Khamnei

    2011-12-01

    Full Text Available Voluntary drinking is one of the major determiners of rehydration, especially as regards exercise or workout in the heat. The present study undertakes to search for the effect of voluntary intake of water with different temperatures on fluid balance in Taekwondo athletes. Six young healthy male Taekwondo athletes were dehydrated by moderate exercise in a chamber with ambient temperature at 38-40°C and relative humidity between 20-30%. On four separate days they were allowed to drink ad libitum plane water with the four temperatures of 5, 16, 26, and 58°C, after dehydration. The volume of voluntary drinking and weight change was measured; then the primary percentage of dehydration, sweat loss, fluid deficit and involuntary dehydration were calculated. Voluntary drinking of water proved to be statistically different in the presented temperatures. Water at 16°C involved the greatest intake, while fluid deficit and involuntary dehydration were the lowest. Intake of water in the 5°C trial significantly correlated with the subject's plasma osmolality change after dehydration, yet it showed no significant correlation with weight loss. In conclusion, by way of achieving more voluntary intake of water and better fluid state, recommending cool water (~16°C for athletes is in order. Unlike the publicly held view, drinking cold water (~5°C does not improve voluntary drinking and hydration status.

  17. TEMPERATURE-DEPENDENCE OF WATER TRANSPORT INTO THE MINERALIZED MATRIX OF FREEZE-DRIED HUMAN DENTIN

    NARCIS (Netherlands)

    VANDERGRAAF, ER; TENBOSCH, JJ

    1991-01-01

    Ten dentine sections cut perpendicular to the dentinal tubules from human mature non-carious third molars, were freeze-dried and then rehydrated by immersion in water at four temperatures, 10, 25, 40 and 70-degrees-C. The uptake of water by the sections was assessed as a function of rehydration

  18. Cavitation erosion of copper and aluminium in water at elevated-temperature

    CSIR Research Space (South Africa)

    Auret, JG

    1993-12-01

    Full Text Available Cavitation erosion tests were carried out in tap water on aluminium and copper samples in a rotating disk cavitations test apparatus, to study the effect of water temperature on cavitation dynamics and cavitation erosion. A shift in the position...

  19. Interactive Effect of Air-Water Ratio and Temperature on the Air ...

    African Journals Online (AJOL)

    High cost of pilot scale studies has led engineers to use simulation to study the factors that affect process performance. This study focuses on the interactive effect of air-water ratio and temperature on the removal of volatile organic compounds from polluted water using packed column air stripper taking benzene as a case ...

  20. A model to predict stream water temperature across the conterminous USA

    Science.gov (United States)

    Catalina Segura; Peter Caldwell; Ge Sun; Steve McNulty; Yang Zhang

    2014-01-01

    Stream water temperature (ts) is a critical water quality parameter for aquatic ecosystems. However, ts records are sparse or nonexistent in many river systems. In this work, we present an empirical model to predict ts at the site scale across the USA. The model, derived using data from 171 reference sites selected from the Geospatial Attributes of Gages for Evaluating...

  1. Leaf Temperature of Maize and Crop Water Stress Index with Variable Irrigation and Nitrogen Supply

    Science.gov (United States)

    Water scarcity due to changing climate, population growth, and economic development is a major threat to the sustainability of irrigated agriculture in the Western United States and other regions around the world. Water stress indices based on crop canopy temperature can be useful for assessing plan...

  2. Protic Salt Polymer Membranes: High-Temperature Water-Free Proton-Conducting Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Gervasio, Dominic Francis [Univ. of Arizona, Tucson, AZ (United States)

    2010-09-30

    This research on proton-containing (protic) salts directly addresses proton conduction at high and low temperatures. This research is unique, because no water is used for proton ionization nor conduction, so the properties of water do not limit proton fuel cells. A protic salt is all that is needed to give rise to ionized proton and to support proton mobility. A protic salt forms when proton transfers from an acid to a base. Protic salts were found to have proton conductivities that are as high as or higher than the best aqueous electrolytes at ambient pressures and comparable temperatures without or with water present. Proton conductivity of the protic salts occurs providing two conditions exist: i) the energy difference is about 0.8 eV between the protic-salt state versus the state in which the acid and base are separated and 2) the chemical constituents rotate freely. The physical state of these proton-conducting salts can be liquid, plastic crystal as well as solid organic and inorganic polymer membranes and their mixtures. Many acids and bases can be used to make a protic salt which allows tailoring of proton conductivity, as well as other properties that affect their use as electrolytes in fuel cells, such as, stability, adsorption on catalysts, environmental impact, etc. During this project, highly proton conducting (~ 0.1S/cm) protic salts were made that are stable under fuel-cell operating conditions and that gave highly efficient fuel cells. The high efficiency is attributed to an improved oxygen electroreduction process on Pt which was found to be virtually reversible in a number of liquid protic salts with low water activity (< 1% water). Solid flexible non-porous composite membranes, made from inorganic polymer (e.g., 10%indium 90%tin pyrophosphate, ITP) and organic polymer (e.g., polyvinyl pyridinium phosphate, PVPP), were found that give conductivity and fuel cell performances similar to phosphoric acid electrolyte with no need for hydration at

  3. Effect of torrefaction on the properties of rice straw high temperature pyrolysis char: Pore structure, aromaticity and gasification activity.

    Science.gov (United States)

    Chen, Handing; Chen, Xueli; Qin, Yueqiang; Wei, Juntao; Liu, Haifeng

    2017-03-01

    The influence of torrefaction on the physicochemical characteristics of char during raw and water washed rice straw pyrolysis at 800-1200°C is investigated. Pore structure, aromaticity and gasification activity of pyrolysis chars are compared between raw and torrefied samples. For raw straw, BET specific surface area decreases with the increased torrefaction temperature at the same pyrolysis temperature and it approximately increases linearly with weight loss during pyrolysis. The different pore structure evolutions relate to the different volatile matters and pore structures between raw and torrefied straw. Torrefaction at higher temperature would bring about a lower graphitization degree of char during pyrolysis of raw straw. Pore structure and carbon crystalline structure evolutions of raw and torrefied water washed straw are different from these of raw straw during pyrolysis. For both raw and water washed straw, CO 2 gasification activities of pyrolysis chars are different between raw and torrefied samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Fast crystalline ice formation at extremely low temperature through water/neon matrix sublimation.

    Science.gov (United States)

    Hama, Tetsuya; Ishizuka, Shinnosuke; Yamazaki, Tomoya; Kimura, Yuki; Kouchi, Akira; Watanabe, Naoki; Sugimoto, Toshiki; Pirronello, Valerio

    2017-07-21

    Crystalline ice formation requires water molecules to be sufficiently mobile to find and settle on the thermodynamically most stable site. Upon cooling, however, diffusion and rearrangement become increasingly kinetically difficult. Water ice grown by the condensation of water vapor in laboratory is thus generally assumed to be in a metastable amorphous form below 100 K. Here, we demonstrate the possibility of crystalline ice formation at extremely low temperature using a water/neon matrix (1/1000, 30 000 monolayers) prepared at 6 K, which is subsequently warmed to 11-12 K. In situ infrared spectroscopy revealed the assembly of the dispersed water molecules, forming crystalline ice I during the sublimation of the neon matrix for 40-250 seconds. This finding indicates that the high mobility of the water molecules during matrix sublimation can overcome the kinetic barrier to form crystals even at extremely low temperature.

  5. Covariation of coastal water temperature and microbial pollution at interannual to tidal periods

    Science.gov (United States)

    Boehm, Alexandria B.; Lluch-Cota, Daniel B.; Davis, Kristen A.; Winant, Clinton D.; Monismith, Stephen G.

    2004-03-01

    Water temperature and fecal indicator bacteria levels covary along the shoreline of Huntington and Newport Beach, California at interannual to tidal periods. During summer, cooler than average waters caused by interannual variability in sea surface temperature (SST), synoptic upwelling, and tidal-period cooling are coincident with elevated levels of microbial pollution in the surf zone. This relationship can be explained by the effects of weakening in stratification on the fate of a waste water plume and the prolonged persistence of fecal indicator bacteria in colder waters. During winter, warmer than average water caused by basin scale oscillations and atmospheric and oceanographic processes that contribute to the Multivariate El Nino Southern Oscillation Index are indicative of elevated total coliform levels in the surf zone. The elevated coliform levels can be ascribed to increased rainfall, and the resultant storm water inflow to the surf zone.

  6. The Impact of Deep Fjord Water Temperatures on the Ice Flow Velocities of Helheim Glacier, Greenland

    Science.gov (United States)

    Karlsson, Nanna B.; Lach, Katarzyna; Grinsted, Aslak; Herraiz-Borreguero, Laura; Messerli, Alexandra

    2017-04-01

    Increasing ice flow velocities of marine terminating glaciers are often linked to rising ocean temperatures. Unfortunately, direct comparisons between glacier velocity and ocean temperatures are impeded by the fact that few oceanographic datasets span multiple years or contain temperatures at depth. Here, we use an oceanographic dataset collected in Helheim Fjord over several years (described in Straneo et al., 2011, Nat. Geoscience) in both shallow and deep waters. We compare the water temperatures at different depths with ice flow velocities that have been calculated from feature-tracking of LandSAT 7 and 8 images. Our results cover the period 2009-2013 and show both seasonal and inter-annual variability. We find that the velocity of Helheim glacier is likely influenced by the deep ocean water temperatures, namely the influx of warm Atlantic water, whereas water temperature at shallower depths do not have a significant influence on glacier speed. This is in contrast with findings from, for example, Svalbard. Our study demonstrates the need for multiple-year ocean datasets at different depths, if we are to disentangle the complex interactions between glaciers and ocean.

  7. A method for the temperature calibration of an infrared camera using water as a radiative source.

    Science.gov (United States)

    Bower, S M; Kou, J; Saylor, J R

    2009-09-01

    Presented here is an effective low-cost method for the temperature calibration of infrared cameras, for applications in the 0-100 degrees C range. The calibration of image gray level intensity to temperature is achieved by imaging an upwelling flow of water, the temperature of which is measured with a thermistor probe. The upwelling flow is created by a diffuser located below the water surface of a constant temperature water bath. The thermistor probe is kept immediately below the surface, and the distance from the diffuser outlet to the surface is adjusted so that the deformation of the water surface on account of the flow is small, yet the difference between the surface temperature seen by the camera and the bulk temperature measured by the thermistor is also small. The benefit of this method compared to typical calibration procedures is that, without sacrificing the quality of the calibration, relatively expensive commercial blackbodies are replaced by water as the radiative source (epsilon approximately 0.98 for the wavelengths considered here). A heat transfer analysis is provided, which improves the accuracy of the calibration method and also provides the user with guidance to further increases in accuracy of the method.

  8. Water Content or Water Activity: What Rules Crispy Behavior in Bread Crust?

    NARCIS (Netherlands)

    Nieuwenhuijzen, van N.H.; Primo-Martin, C.; Meinders, M.B.J.; Tromp, R.H.; Hamer, R.J.; Vliet, van T.

    2008-01-01

    A dry crust loses its crispness when water migrates into the crust. It is not clear if it is the amount of water absorbed or the water activity (aw) that leads to a loss of crispness. The hysteresis effect observed when recording a water sorption isotherm allowed us to study the effects of aw and

  9. Water content or water activity: What rules crispy behavior in bread crust?

    NARCIS (Netherlands)

    Nieuwenhuijzen, N.H. van; Primo-Martín, C.; Meinders, M.B.J.; Tromp, R.H.; Hamer, R.J.; Vliet, T. van

    2008-01-01

    A dry crust loses its crispness when water migrates into the crust. It is not clear if it is the amount of water absorbed or the water activity (a w) that leads to a loss of crispness. The hysteresis effect observed when recording a water sorption isotherm allowed us to study the effects of aw and

  10. The rising cost of warming waters: effects of temperature on the cost of swimming in fishes.

    Science.gov (United States)

    Hein, Andrew M; Keirsted, Katrina J

    2012-04-23

    Understanding the effects of water temperature on the swimming performance of fishes is central in understanding how fish species will respond to global climate change. Metabolic cost of transport (COT)-a measure of the energy required to swim a given distance-is a key performance parameter linked to many aspects of fish life history. We develop a quantitative model to predict the effect of water temperature on COT. The model facilitates comparisons among species that differ in body size by incorporating the body mass-dependence of COT. Data from 22 fish species support the temperature and mass dependencies of COT predicted by our model, and demonstrate that modest differences in water temperature can result in substantial differences in the energetic cost of swimming.

  11. Water temperature, body mass and fasting heat production of pacu (Piaractus mesopotamicus

    Directory of Open Access Journals (Sweden)

    FREDY A.A. AGUILAR

    Full Text Available ABSTRACT Knowledge on fasting heat production (HEf of fish is key to develop bioenergetics models thus improving feeding management of farmed species. The core of knowledge on HEf of farmed, neotropical fish is scarce. This study assessed the effect of body mass and water temperature on standard metabolism and fasting heat production of pacu, Piaractus mesopotamicus, an omnivore, Neotropical fresh water characin important for farming and fisheries industries all through South American continent. An automated, intermittent flow respirometry system was used to measure standard metabolic rate (SMR of pacu (17 - 1,050 g at five water temperatures: 19, 23, 26, 29 and 33 °C. Mass specific SMR increased with increasing water temperature but decreased as function of body mass. The allometric exponent for scaling HEf was 0.788, and lied in the range recorded for all studied warm-water fish. The recorded van't Hoff factor (Q10 for pacu (2.06 shows the species low response to temperature increases. The model HEf = 0.04643×W0.7882×T1.837 allows to predict HEf (kJ d-1 from body mass (W, kg and water temperature (T, °C, and can be used in bioenergetical models for the species.

  12. Laboratory experiment on coalbed-methane desorption influenced by water injection and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, D.; Feng, Z.; Zhao, Y.

    2011-07-15

    The exploration of coalbed-methane (CBM) has significantly increased in the last decade, its exploitation is now widely spread. CBM exploitation technologies involve high-pressure water, which reduces the CBM-desorption capacity resulting in a low efficiency. This study has been conducted to examine the CBM desorption and output after water injection and temperature increase. They developed a new experimental system to simulate water-injection in ideal conditions and study the behaviour of water and methane in a coalbed. These experiments revealed that, at constant temperature, water injection pressure controls the CBM-desorption capacity; and that this capacity is highly increased when the temperature is increased. These results show that a higher temperature would increase the efficiency of CBM exploitation, thus producers are likely to use heating in future CBM technologies. Some advances were made in the knowledge of water pressure and temperature effects on desorption behaviour but further research has to be carried to fully define these effects.

  13. Ambient-temperature incubation for the field detection of Escherichia coli in drinking water.

    Science.gov (United States)

    Brown, J; Stauber, C; Murphy, J L; Khan, A; Mu, T; Elliott, M; Sobsey, M D

    2011-04-01

     Escherichia coli is the pre-eminent microbiological indicator used to assess safety of drinking water globally. The cost and equipment requirements for processing samples by standard methods may limit the scale of water quality testing in technologically less developed countries and other resource-limited settings, however. We evaluate here the use of ambient-temperature incubation in detection of E. coli in drinking water samples as a potential cost-saving and convenience measure with applications in regions with high (>25°C) mean ambient temperatures.   This study includes data from three separate water quality assessments: two in Cambodia and one in the Dominican Republic. Field samples of household drinking water were processed in duplicate by membrane filtration (Cambodia), Petrifilm™ (Cambodia) or Colilert® (Dominican Republic) on selective media at both standard incubation temperature (35–37°C) and ambient temperature, using up to three dilutions and three replicates at each dilution. Matched sample sets were well correlated with 80% of samples (n = 1037) within risk-based microbial count strata (E. coli CFU 100 ml−1 counts of 1000), and a pooled coefficient of variation of 17% (95% CI 15–20%) for paired sample sets across all methods.   These results suggest that ambient-temperature incubation of E. coli in at least some settings may yield sufficiently robust data for water safety monitoring where laboratory or incubator access is limited.

  14. Water color affects the stratification, surface temperature, heat content, and mean epilimnetic irradiance of small lakes

    Science.gov (United States)

    Houser, J.N.

    2006-01-01

    The effects of water color on lake stratification, mean epilimnetic irradiance, and lake temperature dynamics were examined in small, north-temperate lakes that differed widely in water color (1.5-19.8 m -1). Among these lakes, colored lakes differed from clear lakes in the following ways: (i) the epilimnia were shallower and colder, and mean epilimnetic irradiance was reduced; (ii) the diel temperature cycles were more pronounced; (iii) whole-lake heat accumulation during stratification was reduced. The depth of the epilimnion ranged from 2.5 m in the clearest lake to 0.75 m in the most colored lake, and 91% of the variation in epilimnetic depth was explained by water color. Summer mean morning epilimnetic temperature was ???2??C cooler in the most colored lake compared with the clearest lake. In clear lakes, the diel temperature range (1.4 ?? 0.7??C) was significantly (p = 0.01) less than that in the most colored lake (2.1 ?? 1.0??C). Change in whole-lake heat content was negatively correlated with water color. Increasing water color decreased light penetration more than thermocline depth, leading to reduced mean epilimnetic irradiance in the colored lakes. Thus, in these small lakes, water color significantly affected temperature, thermocline depth, and light climate. ?? 2006 NRC.

  15. Electrochemistry of active chromium. Part III. Effects of temperature

    Directory of Open Access Journals (Sweden)

    J. P. POPIC

    2003-11-01

    Full Text Available It was shown that the temperature in the range 20 – 65 ºC has considerable effects on the electrochemical anodic dissolution of chromium in the active potential range as well as on the electrochemical hydrogen evolution reactions on bare and oxide covered chromium surfaces. Also, the chemical dissolution of chromium is strongly affected. The apparent energy of activation for anodic dissolution is 63.1 kJ mol-1, for hydrogen evolution on a bare Cr surface 19.5 kJ mol-1, for the same reaction on an oxide covered surface 44.0 kJ mol-1 and for the chemical (“anomalous” dissolution 66.9 kJ mol-1. The temperature dependences of the total corrosion rate, and the electrochemical corrosion rate alone, are presented in polynomial forms with the appropriate constants obtained by the best fit of the experimental data. For the hydrogen evolution reaction on both bare and oxide covered chromium, the Volmer-Heyrovsky reaction mechanism with the second step as rate determining was proposed.

  16. High Temperature Monitoring the Height of Condensed Water in Steam Pipes

    Science.gov (United States)

    Bar-Cohen, Yoseph; Lih, Shyh-Shiuh; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Widholm, Scott; Ostlund, Patrick; Blosiu, Julian

    2011-01-01

    An in-service health monitoring system is needed for steam pipes to track through their wall the condensation of water. The system is required to measure the height of the condensed water inside the pipe while operating at temperatures that are as high as 250 deg. C. The system needs to be able to make real time measurements while accounting for the effects of cavitation and wavy water surface. For this purpose, ultrasonic wave in pulse-echo configuration was used and reflected signals were acquired and auto-correlated to remove noise from the data and determine the water height. Transmitting and receiving the waves is done by piezoelectric transducers having Curie temperature that is significantly higher than 250 deg. C. Measurements were made at temperatures as high as 250 deg. C and have shown the feasibility of the test method. This manuscript reports the results of this feasibility study.

  17. Polymer functionalized nanostructured porous silicon for selective water vapor sensing at room temperature

    Science.gov (United States)

    Dwivedi, Priyanka; Das, Samaresh; Dhanekar, Saakshi

    2017-04-01

    This paper highlights the surface treatment of porous silicon (PSi) for enhancing the sensitivity of water vapors at room temperature. A simple and low cost technique was used for fabrication and functionalization of PSi. Spin coated polyvinyl alcohol (PVA) was used for functionalizing PSi surface. Morphological and structural studies were conducted to analyze samples using SEM and XRD/Raman spectroscopy respectively. Contact angle measurements were performed for assessing the wettability of the surfaces. PSi and functionalized PSi samples were tested as sensors in presence of different analytes like ethanol, acetone, isopropyl alcohol (IPA) and water vapors in the range of 50-500 ppm. Electrical measurements were taken from parallel aluminium electrodes fabricated on the functionalized surface, using metal mask and thermal evaporation. Functionalized PSi sensors in comparison to non-functionalized sensors depicted selective and enhanced response to water vapor at room temperature. The results portray an efficient and selective water vapor detection at room temperature.

  18. Numerical simulation of severe water ingress accidents in a modular high temperature gas cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zuoyi; Scherer, W.

    1996-01-01

    This report analyzes reverse water ingress accidents in the SIEMENS 200 MW Modular Pebble-Bed High Temperature Gas Cooled Reactor (HTR-MODULE) under the assumption of no active safety protection systems in order to find the safety margins of the current HTR-MODULE design and to realize a catastrophe-free nuclear technology. A water, steam and helium multi-phase cavity model is developed and implemented in the DSNP simulation system. The DSNP system is then used to simulate the primary and secondary circuit of a HTR-MODULE power plant. Comparisons of the model with experiments and with TINTE calculations serve as validation of the simulation. The analysis of the primary circuit tries to answer the question how fast the water enters the reactor core. It was found that the maximum H{sub 2}O concentration increase in the reactor core is smaller than 0.3 kg/(m{sup 3}s). The liquid water vaporization in the steam generator and H{sub 2}O transport from the steam generator to the reactor core reduce the ingress velocity of the H{sub 2}O into the reactor core. In order to answer the question how much water enters the primary circuit, the full cavitation of the feed water pumps is analyzed. It is found that if the secondary circuit is depressurized enough, the feed water pumps will be inherently stopped by the full cavitation. This limits the water to be pumped from the deaerator to the steam generator. A comprehensive simulation of the MODUL-HTR power plant then shows that the H{sub 2}O inventory in the primary circuit can be limited to about 3000 kg. The nuclear reactivity increase caused by the water ingress leads to a fast power excursion, which, however, is inherently counterbalanced by negative feedback effects. Concerning the integrity of the fuel elements, the safety relevant temperature limit of 1600 C was not reached in any case. (orig.) [Deutsch] Dieser Bericht analysiert schwere Wassereinbruch-Stoerfaelle im 200 MW modularen Kugelhaufen-Hochtemperaturreaktor (HTR

  19. Research on Efficiency of Ozonation and Bromate Formation in Low Temperature and Low Turbidity Water

    Science.gov (United States)

    Zhu, Qi; Liu, Dongmei; Cui, Fuyi; Fang, Lei; Zhao, Zhiwei; Liu, Tongmian

    2010-11-01

    The efficiency of ozonation and the influence factor of bromate formation were studied in filtered water at low temperature and low turbidity in Harbin Shaohe water treatment plant, of which source water was from Songhua river. The results showed that when adding 3 mg/L O3 to the filtered water, the average removal rate of UV254 were 22.31%, the removal rate of TOC in filtered water were 6.33%. When adding 2 mg/L O3 and 4 mg/L O3 to the filtered water, the CODMn decreased by 21.53% and 24.68%, respectively. Ozonation had no obvious effect on reducing turbidity and the content of ammonia nitrogen of filtered water in Shaohe water treatment plant. It could be found that the formation amount of BrO3- would increase with the concentration of Br- increasing in low temperature and low turbidity water. When Ct value of filtered water in Shaohe water treatment plant was less than 30 mgṡL-1ṡmin, the formation amount of BrO3- could be controlled under 10 μg/L.

  20. Investigation on physicochemical properties of plasma-activated water for the application of medical device sterilization

    Science.gov (United States)

    Abuzairi, Tomy; Ramadhanty, Savira; Puspohadiningrum, Dini Fithriaty; Ratnasari, Anita; Poespawati, Nji Raden; Purnamaningsih, Retno Wigajatri

    2018-02-01

    Plasma activated water (PAW) is a new approach to bacterial inactivation while ensuring safety and maintaining the properties of the material sterilized. Reported research imply that PAW has been effective for inactivation of bacteria. In this paper, plasma treatment using atmospheric pressure plasma was demonstrated. Physicochemical properties such as pH, temperature, ORP, and nitrite concentration were assessed. The results suggest that plasma treatment causes acidification on water and generate reactive species, creating an environment suitable for killing bacteria. Therefore, plasma activated water is an assuring method for medical devices sterilization.

  1. The Effect of Geomorphic Complexity on Water Temperature in a Pacific Northwest Alluvial River

    Science.gov (United States)

    Arrigoni, A. S.; Poole, G. C.; Thomas, S. A.; Woessner, W. W.; Mertes, L. A.; Boer, B. R.; O'Daniel, S. J.

    2003-12-01

    Hyporheic exchange of ground and surface water is an important physical process that contributes to the habitat template of alluvial rivers and is known to increase thermal diversity within streams by creating localized or isolated pockets where water temperature is buffered. Although the Umatilla River in northeastern Oregon, USA once supported healthy populations of salmonids (trout, salmon, and charr), summertime water temperatures in the river are now stressful or lethal to salmonids, exceeding 26° C. Using funding from NASA, the Confederated Tribes of the Umatilla Indian Reservation are coordinating the Data Rich Decision Support Environment research project to study the hydrologic and thermal regime of the river. As part of that study, we are documenting the influence of near-channel hyporheic exchange on the river's thermal regime. We instrumented a variety of stream channel units (pools, riffles, spring channels, etc.) and gravel bars with more than 70 temperature loggers. These were used to describe the thermal diversity of the channel and hyporheic zone in geomorphically complex settings where hyporheic exchange is prevalent. The loggers were deployed over a 4-week period during July and August. To monitor surface water temperatures loggers were attached to rebar that was pounded into the stream bed. For monitor hyporheic water temperatures loggers were placed in piezometers set 15 cm to 2 m into gravels . A total station was used to survey bar and streambed topography along with the locations of the temperature loggers. Resulting data suggest that complex channel patterns and bed-forms create hydraulic gradients within the near-channel aquifer that enhance hyporheic exchange. In addition to creating the expected localized patterns of thermal diversity in the stream channel near upwelling water, our data suggest that the cumulative affect of geomorphically complex nodes within the river have the ability to buffer diel temperature variation in the main

  2. Response of water temperatures and stratification to changing climate in three lakes with different morphometry

    Directory of Open Access Journals (Sweden)

    M. R. Magee

    2017-12-01

    Full Text Available Water temperatures and stratification are important drivers for ecological and water quality processes within lake systems, and changes in these with increases in air temperature and changes to wind speeds may have significant ecological consequences. To properly manage these systems under changing climate, it is important to understand the effects of increasing air temperatures and wind speed changes in lakes of different depths and surface areas. In this study, we simulate three lakes that vary in depth and surface area to elucidate the effects of the observed increasing air temperatures and decreasing wind speeds on lake thermal variables (water temperature, stratification dates, strength of stratification, and surface heat fluxes over a century (1911–2014. For all three lakes, simulations showed that epilimnetic temperatures increased, hypolimnetic temperatures decreased, the length of the stratified season increased due to earlier stratification onset and later fall overturn, stability increased, and longwave and sensible heat fluxes at the surface increased. Overall, lake depth influences the presence of stratification, Schmidt stability, and differences in surface heat flux, while lake surface area influences differences in hypolimnion temperature, hypolimnetic heating, variability of Schmidt stability, and stratification onset and fall overturn dates. Larger surface area lakes have greater wind mixing due to increased surface momentum. Climate perturbations indicate that our larger study lakes have more variability in temperature and stratification variables than the smaller lakes, and this variability increases with larger wind speeds. For all study lakes, Pearson correlations and climate perturbation scenarios indicate that wind speed has a large effect on temperature and stratification variables, sometimes greater than changes in air temperature, and wind can act to either amplify or mitigate the effect of warmer air temperatures on

  3. Low temperature FMR investigations on double surfactant water based ferrofluid

    Science.gov (United States)

    Shankar, Ajay; Chand, Mahesh; Basheed, Gounda Abdul; Thakur, Sanjeeve; Pant, Rajendra Prasad

    2015-01-01

    Magnetite nanoparticles were synthesized by coprecipitation of reverse micelles in an aqueous phase. XRD, TEM and VSM results confirm the average particle size 9-10 nm. The FMR measurements were performed in zero-field-cooled (ZFC) and field-cooled (FC) protocol. Raikher and Morais models were used for interpreting the resonance field and linewidth results. A value of 2.3×10-2 erg cm-2 for intrinsic surface anisotropy constant is observed as per the Raikher model. The higher melting point of water leaves the magnetic particles with a more disordered distribution of anisotropy axes of particles even in FC measurements. The angular variation of resonance field differentiates the magnetic behavior of system in 4-40 K (region I), 70-200 K (region II) and 200-260 K (region III). The value of effective magnetic anisotropy constant varied from 4.7×104, 2.1×104 to 0 erg cm-3 through regions I, II to III. Linewidth analysis reveals that system undergoes spin-glass transition ~46 K. The fitting of linewidth data for region I and II indicate the presence of frozen and unfrozen surface spin states. Moreover, the role of applied magnetic field i.e. 1 T in field-cooled FMR spectra is reflected in interparticle distance parameter and magnitude of energy barriers related to the relaxation mechanisms. At 260 K fluid melts resulting in minimization of angular dependent anisotropy in resonance lines.

  4. Measurement of water vapour transport through a porous non-hygroscopic material in a temperature gradient

    DEFF Research Database (Denmark)

    Hansen, Thor; Padfield, Tim; Hansen, Kurt Kielsgaard

    2014-01-01

    This was an experiment to identify the driving potential for water vapour diffusion through porous materials in a temperature gradient. The specimen of mineral fibre insulation was placed between a space with controlled temperature and relative humidity and a space with a controlled, higher...... temperature, and a measured but not controlled relative humidity (RH). This assembly was allowed to reach equilibrium with no vapour movement between the spaces, as tested by a constant RH on each side and by zero flux of water vapour measured in the cold side chamber. The RH and temperature values were...... be tested experimentally in this way, but it is reasonable to assume that concentration is the driving potential. The close equality of the concentrations makes it unnecessary to invoke temperature difference as a third possible potential for driving diffusion....

  5. Visible Light Activated Photocatalytic Water Polishing System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal targets development of a LED light activated photocatalytic water polishing system that enables reduction of organic impurities (TOC and...

  6. Heat transfer coefficient: Medivance Arctic Sun Temperature Management System vs. water immersion.

    Science.gov (United States)

    English, M J; Hemmerling, T M

    2008-07-01

    To improve heat transfer, the Medivance Arctic Sun Temperature Management System (Medivance, Inc., Louisville, CO, USA) features an adhesive, water-conditioned, highly conductive hydrogel pad for intimate skin contact. This study measured and compared the heat transfer coefficient (h), i.e. heat transfer efficiency, of this pad (hPAD), in a heated model and in nine volunteers' thighs; and of 10 degrees C water (hWATER) in 33 head-out immersions by 11 volunteers. Volunteer studies had ethical approval and written informed consent. Calibrated heat flux transducers measured heat flux (W m-2). Temperature gradient (DeltaT) was measured between skin and pad or water temperatures. Temperature gradient was changed through the pad's water temperature controller or by skin cooling on immersion. The heat transfer coefficient is the slope of W m-2/DeltaT: its unit is W m-2 degrees C-1. Average with (95% CI) was: model, hPAD = 110.4 (107.8-113.1), R2 = 0.99, n = 45; volunteers, hPAD = 109.8 (95.5-124.1), R2 = 0.83, n = 51; and water immersion, hWATER = 107.1 (98.1-116), R2 = 0.86, n = 94. The heat transfer coefficient for the pad was the same in the model and volunteers, and equivalent to hWATER. Therefore, for the same DeltaT and heat transfer area, the Arctic Sun's heat transfer rate would equal water immersion. This has important implications for body cooling/rewarming rates.

  7. Shifts in identity and activity of methanotrophs in arctic lake sediments in response to temperature changes

    Science.gov (United States)

    He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

    2012-01-01

    Methane (CH4) flux to the atmosphere is mitigated via microbial CH4 oxidation in sediments and water. As arctic temperaturesincrease, understanding the effects of temperature on the activity and identity of methanotrophs in arctic lake sediments is importantto predicting future CH4 emissions. We used DNA-based stable-isotope probing (SIP), quantitative PCR (Q-PCR), andpyrosequencing analyses to identify and characterize methanotrophic communities active at a range of temperatures (4°C, 10°C,and 21°C) in sediments (to a depth of 25 cm) sampled from Lake Qalluuraq on the North Slope of Alaska. CH4 oxidation activitywas measured in microcosm incubations containing sediments at all temperatures, with the highest CH4 oxidation potential of37.5 mol g1 day1 in the uppermost (depth, 0 to 1 cm) sediment at 21°C after 2 to 5 days of incubation. Q-PCR of pmoA and ofthe 16S rRNA genes of type I and type II methanotrophs, and pyrosequencing of 16S rRNA genes in 13C-labeled DNA obtained bySIP demonstrated that the type I methanotrophs Methylobacter, Methylomonas, and Methylosoma dominated carbon acquisitionfrom CH4 in the sediments. The identity and relative abundance of active methanotrophs differed with the incubation temperature.Methylotrophs were also abundant in the microbial community that derived carbon from CH4, especially in the deeper sediments(depth, 15 to 20 cm) at low temperatures (4°C and 10°C), and showed a good linear relationship (R0.82) with the relativeabundances of methanotrophs in pyrosequencing reads. This study describes for the first time how methanotrophiccommunities in arctic lake sediments respond to temperature variations.

  8. Total phenol content and antioxidant activity of water solutions of plant extracts

    OpenAIRE

    Kopjar, Mirela; Piližota, Vlasta; Hribar, J.; Simčić, M.

    2009-01-01

    Water solutions of extracts were investigated for total phenol content, flavonoid content and antioxidant activity. Susceptibility to degradation of water solutions of plant extracts, under light and in the dark, during storage at room temperature was investigated in order to determine their stability prior to their application for fortification of food products. Large dispersion of total phenol (TP) content in the investigated model solutions of selected extracts (olive leaves, green tea, re...

  9. Effects of ozonation and temperature on biodegradation of natural organic matter in biological granular activated carbon filters

    NARCIS (Netherlands)

    Van der Aa, L.T.J.; Rietveld, L.C.; Van Dijk, J.C.

    2010-01-01

    Four pilot (biological) granular activated carbon ((B)GAC) filters were operated to quantify the effects of ozonation and water temperature on the biodegradation of natural organic matter (NOM) in (B)GAC filters. Removal of dissolved organic carbon (DOC), assimilable organic carbon (AOC) and oxygen

  10. Effects of ozonation and temperature on the biodegradation of natural organic matter in biological granular activated carbon filters

    NARCIS (Netherlands)

    Van der Aa, L.T.J.; Rietveld, L.C.; Van Dijk, J.C.

    2011-01-01

    Four pilot (biological) granular activated carbon ((B)GAC) filters were operated to quantify the effects of ozonation and water temperature on the biodegradation of natural organic matter (NOM) in (B)GAC filters. The removal of dissolved organic carbon (DOC), assimilable organic carbon (AOC) and

  11. Investigating aftergrowth potential of polymers in drinking water – the effect of water replacement and temperature

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Albrechtsen, Hans-Jørgen

    The aftergrowth potential of polymers used in drinking water distribution was investigated by a batch set-up, where test pieces were incubated in biostable, inorganic nutrient amended drinking water inoculated with surface water. Biomass production was measured as ATP and followed over 16 weeks...... no significant effect on the aftergrowth potential of the water. The background biomass production could be affected by the choice of caps for the test bottles, since ‘blue caps’ of polyethylene leached significant amounts of AOCP17 compared to ‘red caps’ containing teflon inlayers. There was no or only slightly...... difference on the biomass production of no replacement of the test water, replacement once a week or every second week. Periodical water replacement could nevertheless be considered beneficial, since a substantial NVOC migration occurred within the first six weeks of incubation, which potentially could...

  12. Effect of different water temperatures on growth of aquatic plants Salvinia natans and Ceratophyllum demersum

    Directory of Open Access Journals (Sweden)

    Khadija Kadhem Hreeb

    2016-12-01

    Full Text Available Objective: To evaluate the effect of some different water temperatures on growth of aquatic plants (Salvinia natans and Ceratophyllum demersum. Methods: The aquatic plants were brought from Shatt Al-Arab River in 2016. Equal weights of aquatic plants were aquacultured in aquaria, and were exposed to three different temperatures ( 12, 22 and 32 °C. Results: The results showed that the two plants did not show significant differences with respect to their effects on pH and electrical conductivity values. Time and temperature did not affect the values of pH and electrical conductivity. The values of dissolved oxygen was significantly influenced with variation of time and temperature, while the two plants did not have significant differences on dissolved oxygen values, nitrate ion concentration and was not significantly influenced with variation of plant species or temperature or time. Plant species and temperature significantly affected phosphate ion concentration, while the time did not significantly influence the concentration of phosphate ion. Chlorophyll a content and biomass were significantly influenced with the variation of plant species, and temperature . Conclusions: Aquatic plants has a species specific respond to temperatures change in their environment. Water plant, Ceratophyllum demersum is more tolerant to temperatures change than Salvinia natans.

  13. Evaporation of oil-water emulsion drops when heated at high temperature

    Science.gov (United States)

    Strizhak, P. A.; Piskunov, M. V.; Kuznetsov, G. V.; Voytkov, I. S.

    2017-10-01

    An experimental study on conditions and main characteristics for high-temperature (more than 700 K) evaporation of oil-water drops is presented. The high-temperature water purification from impurities can be the main practical application of research results. Thus, the heating of drops is implemented by the two typical schemes: on a massive substrate (the heating conditions are similar to those achieved in a heating chamber) and in a flow of the heated air. In the latter case, the heating conditions correspond to those attained while moving water drops with impurities in a counter high-temperature gaseous flow in the process of water purification. Evaporation time as function of heating temperature is presented. The influence of oil product concentration in an emulsion drop on evaporation characteristics is discussed. The conditions for intensive flash boiling of an emulsion drop and its explosive breakup with formation of the fine droplets cloud are pointed out. Heat fluxes required for intensive flash boiling and explosive breakup of a drop with further formation of the fine aerosol are determined in the boundary layer of a drop. The fundamental differences between flash boiling and explosive breakup of an emulsion drop when heated on a substrate and in a flow of the heated air are described. The main prospects for the development of the high-temperature water purification technology are detailed taking into account the fast emulsion drop breakup investigated in the paper.

  14. Influence of dehydration temperature on water vapor adsorption, dissolution behavior and surface property of ampicillin.

    Science.gov (United States)

    Moribe, Kunikazu; Wongmekiat, Arpansiree; Hyakutake, Yuki; Tozuka, Yuichi; Oguchi, Toshio; Yamamoto, Keiji

    2005-01-20

    Several specimens of anhydrous ampicillin were prepared by heating the ampicillin trihydrate at 100, 120, 140 and 160 degrees C. The effects of dehydration temperature on water vapor adsorption, dissolution behavior and surface property were investigated. The water vapor adsorption of anhydrous ampicillin was studied at 89% relative humidity, 40 degrees C and the water vapor adsorption rate was found to decrease with increase of dehydration temperature. Dissolution profiles of the various anhydrous specimens were investigated in 96% ethanol at 35 degrees C by the static disk method. The anhydrous form prepared at higher dehydration temperature exhibited faster dissolution rate. Solid phase transformation from the anhydrous form to the trihydrate form occurred during the dissolution test. The rate of phase transformation during the dissolution test decreased with increasing dehydration temperature. Topographic difference of the anhydrous forms prepared at 100 and 160 degrees C was not observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM); however, difference of the microstructural properties was apparently observed by the AFM phase image. Surface free energy study revealed that when ampicillin was dehydrated at high temperature, the sample surface became more hydrophobic resulting in less interaction force with water and slow water sorption rate. From the results, we concluded that the polarity of sample surface induced by dehydration of ampicillin would affect the phase transformation and dissolution behavior.

  15. Parameterizing deep water percolation improves subsurface temperature simulations by a multilayer firn model

    Science.gov (United States)

    Marchenko, Sergey; van Pelt, Ward J. J.; Claremar, Björn; Pohjola, Veijo; Pettersson, Rickard; Machguth, Horst; Reijmer, Carleen

    2017-03-01

    Deep preferential percolation of melt water in snow and firn brings water lower along the vertical profile than a laterally homogeneous wetting front. This widely recognized process is an important source of uncertainty in simulations of subsurface temperature, density and water content in seasonal snow and in firn packs on glaciers and ice sheets. However, observation and quantification of preferential flow is challenging and therefore it is not accounted for by most of the contemporary snow/firn models. Here we use temperature measurements in the accumulation zone of Lomonosovfonna, Svalbard, done in April 2012 - 2015 using multiple thermistor strings to describe the process of water percolation in snow and firn. Effects of water flow through the snow and firn profile are further explored using a coupled surface energy balance - firn model forced by the output of the regional climate model WRF. In situ air temperature, radiation and surface height change measurements are used to constrain the surface energy and mass fluxes. To account for the effects of preferential water flow in snow and firn we test a set of depth-dependent functions allocating a certain fraction of the melt water available at the surface to each snow/firn layer. Experiments are performed for a range of characteristic percolation depths and results indicate a reduction in root mean square difference between the modeled and measured temperature by up to a factor of two compared to the results from the default water infiltration scheme. This illustrates the significance of accounting for preferential water percolation to simulate subsurface conditions. The suggested approach to parameterization of the preferential water flow requires low additional computational cost and can be implemented in layered snow/firn models applied both at local and regional scales, for distributed domains with multiple mesh points.

  16. Adiabatic flame temperature of sodium combustion and sodium-water reaction

    Energy Technology Data Exchange (ETDEWEB)

    Okano, Y.; Yamaguchi, A. [Japan Nuclear Cycle Development Institute, Ibaraki (Japan)

    2001-07-01

    In this paper, background information of sodium fire and sodium-water reaction accidents of LMFBR (liquid metal fast breeder reactor) is mentioned at first. Next, numerical analysis method of GENESYS is described in detail. Next, adiabatic flame temperature and composition of sodium combustion are analyzed, and affect of reactant composition, such oxygen and moisture, is discussed. Finally, adiabatic reaction zone temperature and composition of sodium-water reaction are calculated, and affects of reactant composition, sodium vaporization, and pressure are stated. Chemical equilibrium calculation program for generic chemical system (GENESYS) is developed in this study for the research on adiabatic flame temperature of sodium combustion and adiabatic reaction zone temperature of sodium-water reaction. The maximum flame temperature of the sodium combustion is 1,950 K at the standard atmospheric condition, and is not affected by the existence of moisture. The main reaction product is Na{sub 2}O{sub (l)}, and in combustion in moist air, with NaOH{sub (g)}. The maximum reaction zone temperature of the sodium-water reaction is 1,600 K, and increases with the system pressure. The main products are NaOH{sub (g)}, NaOH{sub (l)} and H2{sub (g)}. Sodium evaporation should be considered in the cases of sodium-rich and high pressure above 10 bar.

  17. Annual Changes in Seasonal River Water Temperatures in the Eastern and Western United States

    Directory of Open Access Journals (Sweden)

    Tyler Wagner

    2017-02-01

    Full Text Available Changes in river water temperatures are anticipated to have direct effects on thermal habitat and fish population vital rates, and therefore, understanding temporal trends in water temperatures may be necessary for predicting changes in thermal habitat and how species might respond to such changes. However, many investigations into trends in water temperatures use regression methods that assume long-term monotonic changes in temperature, when in fact changes are likely to be nonmonotonic. Therefore, our objective was to highlight the need and provide an example of an analytical method to better quantify the short-term, nonmonotonic temporal changes in thermal habitat that are likely necessary to determine the effects of changing thermal conditions on fish populations and communities. To achieve this objective, this study uses Bayesian dynamic linear models (DLMs to examine seasonal trends in river water temperatures from sites located in the eastern and western United States, regions that have dramatically different riverine habitats and fish communities. We estimated the annual rate of change in water temperature and found little evidence of seasonal changes in water temperatures in the eastern U.S. We found more evidence of warming for river sites located in the western U.S., particularly during the fall and winter seasons. Use of DLMs provided a more detailed view of temporal dynamics in river thermal habitat compared to more traditional methods by quantifying year-to-year changes and associated uncertainty, providing managers with the information needed to adapt decision making to short-term changes in habitat conditions that may be necessary for conserving aquatic resources in the face of a changing climate.

  18. Annual changes in seasonal river water temperatures in the eastern and western United States

    Science.gov (United States)

    Wagner, Tyler; Midway, Stephen R.; Whittier, Joanna B.; DeWeber, Jefferson T.; Paukert, Craig

    2017-01-01

    Changes in river water temperatures are anticipated to have direct effects on thermal habitat and fish population vital rates, and therefore, understanding temporal trends in water temperatures may be necessary for predicting changes in thermal habitat and how species might respond to such changes. However, many investigations into trends in water temperatures use regression methods that assume long-term monotonic changes in temperature, when in fact changes are likely to be nonmonotonic. Therefore, our objective was to highlight the need and provide an example of an analytical method to better quantify the short-term, nonmonotonic temporal changes in thermal habitat that are likely necessary to determine the effects of changing thermal conditions on fish populations and communities. To achieve this objective, this study uses Bayesian dynamic linear models (DLMs) to examine seasonal trends in river water temperatures from sites located in the eastern and western United States, regions that have dramatically different riverine habitats and fish communities. We estimated the annual rate of change in water temperature and found little evidence of seasonal changes in water temperatures in the eastern U.S. We found more evidence of warming for river sites located in the western U.S., particularly during the fall and winter seasons. Use of DLMs provided a more detailed view of temporal dynamics in river thermal habitat compared to more traditional methods by quantifying year-to-year changes and associated uncertainty, providing managers with the information needed to adapt decision making to short-term changes in habitat conditions that may be necessary for conserving aquatic resources in the face of a changing climate.

  19. Low-Temperature Miscibility of Ethanol-Gasoline-Water Blends in Flex Fuel Applications

    DEFF Research Database (Denmark)

    Johansen, T.; Schramm, Jesper

    2009-01-01

    The miscibility of blends of gasoline and hydrous ethanol was investigated experimentally at - 25 degrees C and - 2 degrees C. Furthermore, the maximum water content was found for ethanol in flex fuel blends. The results strongly indicate that blends containing ethanol with a water content above...... that of the ethanol/water azeotrope (4.4% water by mass) can be used as Flex Fuel blends together with gasoline at ambient temperatures of 25 degrees C and 2 degrees C, without phase separation occurring. Additionally, it was shown that the ethanol purity requirement of ethanol-rich flex fuel blends falls...... with increasing ethanol content in the gasoline-rich flex fuel blend....

  20. Eclosion rate, development and survivorship of Aedes albopictus (Skuse)(Diptera: Culicidae) under different water temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Laura C.C. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Programa de Pos-Graduacao em Biologia Animal (PPGBA). Curso de Ciencias Biologicas; Souza, Jose R.B. de; Albuquerque, Cleide M.R. de [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Programa de Pos-Graduacao em Biologia Animal (PPGBA). Dept. de Zoologia

    2007-11-15

    In tropical areas, where vector insects populations are particularly numerous, temperature usually range between 25 de C and 35 deg C. Considering the importance of such temperature variation in determining mosquitoes population dynamics, in this work the developmental, eclosion and survival rates of the immature stages of Aedes albopictus (Skuse) were compared under constant 25, 30 and 35 deg C (using acclimatized chambers) and environmental (25 deg C to 29 deg C) temperatures. The hatching rate was considered as total number of larvae recovered after 24h. The development period as well as larval and pupal survival rate were evaluated daily. Eclosion rate was significantly higher under environmental temperature than under the studied constant temperatures, suggesting that temperature variation may be an eclosion-stimulating factor. The mean eclosion time increased with the temperature, ranging from 2.8 h (25 deg C) to 5.2 h (35 deg C). The larval period was greatly variable inside each group, although it did not differ significantly amongst groups (11.0 +- 4.19 days), with individuals showing longer larval stages in water at 35 deg C (12.0 +- 4.95 days) and environmental temperature (13.6 +- 5.98 days). Oppositely, survival was strongly affected by the higher temperature, where only one individual lived through to adult phase. The results suggest that population of Ae. albopictus from Recife may be adapting to increasing of environmental temperatures and that the limiting temperature to larval development is around 35 deg C. (author)

  1. Response of New zealand mudsnails Potamopyrgus antipodarum to freezing and near freezing fluctuating water temperatures

    Science.gov (United States)

    Moffitt, Christine M.; James, Christopher A.

    2012-01-01

    We explored the resilience of the invasive New Zealand mudsnail Potamopyrgus antipodarum to fluctuating winter freezing and near-freezing temperature cycles in laboratory tests. Our goal was to provide data to confirm field observations of mortality and presumed mortality in stream habitats with fluctuating freezing to near-freezing temperatures. We tested individuals from 2 locations with distinctly different thermal regimes and population densities. One location had low snail densities and water temperatures with strong diel and seasonal water variation. The other location had high snail densities and nearly constant water temperatures. Groups of individuals from both locations were tested in each of 3 laboratory-created diel thermal cycles around nominal temperatures of 0, 2, or 4°C. Mortality occurred in cycles around 0°C in both populations, and little to no mortality occurred at temperatures >0°C. Individuals from both sources held in diel 0°C cycles for 72 h showed 100% mortality. Our findings support observations from published field studies that survival was limited in infested habitats subject to freezing temperatures.

  2. Deactivation of Pd Catalysts by Water during Low Temperature Methane Oxidation Relevant to Natural Gas Vehicle Converters

    Directory of Open Access Journals (Sweden)

    Rahman Gholami

    2015-03-01

    Full Text Available Effects of H2O on the activity and deactivation of Pd catalysts used for the oxidation of unburned CH4 present in the exhaust gas of natural-gas vehicles (NGVs are reviewed. CH4 oxidation in a catalytic converter is limited by low exhaust gas temperatures (500–550 °C and low concentrations of CH4 (400–1500 ppmv that must be reacted in the presence of large quantities of H2O (10–15% and CO2 (15%, under transient exhaust gas flows, temperatures, and compositions. Although Pd catalysts have the highest known activity for CH4 oxidation, water-induced sintering and reaction inhibition by H2O deactivate these catalysts. Recent studies have shown the reversible inhibition by H2O adsorption causes a significant drop in catalyst activity at lower reaction temperatures (below 450 °C, but its effect decreases (water adsorption becomes more reversible with increasing reaction temperature. Thus above 500 °C H2O inhibition is negligible, while Pd sintering and occlusion by support species become more important. H2O inhibition is postulated to occur by either formation of relatively stable Pd(OH2 and/or partial blocking by OH groups of the O exchange between the support and Pd active sites thereby suppressing catalytic activity. Evidence from FTIR and isotopic labeling favors the latter route. Pd catalyst design, including incorporation of a second noble metal (Rh or Pt and supports high O mobility (e.g., CeO2 are known to improve catalyst activity and stability. Kinetic studies of CH4 oxidation at conditions relevant to natural gas vehicles have quantified the thermodynamics and kinetics of competitive H2O adsorption and Pd(OH2 formation, but none have addressed effects of H2O on O mobility.

  3. Sensitivity of grapevine phenology to water availability, temperature and CO2 concentration

    Directory of Open Access Journals (Sweden)

    Johann Martínez-Lüscher

    2016-07-01

    Full Text Available In recent decades, mean global temperatures have increased in parallel with a sharp rise in atmospheric carbon dioxide (CO2 levels, with apparent implications for precipitation patterns. The aim of the present work is to assess the sensitivity of different phenological stages of grapevine to temperature and to study the influence of other factors related to climate change (water availability and CO2 concentration on this relationship. Grapevine phenological records from 9 plantings between 42.75°N and 46.03°N consisting of dates for budburst, flowering and fruit maturity were used. In addition, we used phenological data collected from two years of experiments with grapevine fruit-bearing cuttings with two grapevine varieties under two levels of water availability, two temperature regimes and two levels of CO2. Dormancy breaking and flowering were strongly dependent on spring temperature, while neither variation in temperature during the chilling period nor precipitation significantly affected budburst date. The time needed to reach fruit maturity diminished with increasing temperature and decreasing precipitation. Experiments under semi-controlled conditions revealed great sensitivity of berry development to both temperature and CO2. Water availability had significant interactions with both temperature and CO2; however, in general, water deficit delayed maturity when combined with other factors. Sensitivities to temperature and CO2 varied widely, but higher sensitivities appeared in the coolest year, particularly for the late ripening variety, ‘White Tempranillo’. The knowledge gained in whole plant physiology and multi stress approaches is crucial to predict the effects of climate change and to design mitigation and adaptation strategies allowing viticulture to cope with climate change.

  4. Practical Active Disturbance Rejection Solution for Furnace Temperature Control System

    Directory of Open Access Journals (Sweden)

    Jian Huan Su

    2014-08-01

    Full Text Available A practical active disturbance rejection control (ADRC solution is proposed for the furnace temperature system. Employing a linear reduced-order model with optimized parameters, the practical ADRC is simple to use, easy to tune and energy-efficient in dealing with the uncertainties and disturbances in plant dynamics. Through the order reduction in both the plant model and the state observer, we develop a first order extended state observer for estimating in real-time the total value of the external and internal disturbances. The practical and standard ADRCs outperform the Smith Predictor and the PID controller in disturbance-rejection and robustness; however, the practical ADRC has fewer adjustable parameters and significantly smaller energy consumption than the standard ADRC, making it a viable candidate for industrial applications.

  5. Activation of water coolant in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Khripunov, V.; Santoro, R.T.; Lida, H.; Parker, R.; Janeschitz, G.; Plenteda, R. [ITER Joint Central Team Garching, Muenchen (Germany)

    1998-07-01

    Water as been selected as the main coolant for the ITER blanket and vacuum vessel. Following exposure to DT neutrons, water becomes a source of high energy {sup 16}N-decay photons and energetic ({approx}0.9 MeV) {sup 17}N decay neutrons outside the reactor that lead to shielding problems during both reactor operation and after shutdown. As a result of comprehensive neutronic and hydraulic analyses, corresponding design measures were developed to diminish these effects. The use of a correlation between the {sup 16}N-production rate and the 14.1-MeV neutron flux in flowing water was recommended for determining fusion power by measuring water decay photons behind the radiation shield. (authors)

  6. Corrosion inhibition in drinking water. Effect of temperature. Part 2. Copper. Inhibicion de la corrosion en agua potable. Efecto de la temperature. Parte II Cobre

    Energy Technology Data Exchange (ETDEWEB)

    Royuela, J.J.; Otero, E. (CENIM.CSIC. (Spain))

    1994-01-01

    The corrosivity of several drinking waters, with and without addition of sodium silicate and sodium polyphosphate as inhibitor, in contact with copper, is studied in the range, is the range 20-65 degree centigree. The corrosion rate in the course of time was followed by means of the polarization resistance method. Linearity between potential and intensity of current is observed in the range- 30 to + 40 mV in relation with corrosion potential, E[sub 0]. Polarization curves were also drawn with the aim to obtain the Tafel slopes. E[sub 0] values are more active when inhibitor is present. With temperature increases corrosion rate. Inhibitor addition to the drinking water tested means a reduction of copper corrosion of about 50%. (Author) 31 refs.

  7. Experimental design to optimize preparation of activated carbons for use in water treatment.

    Science.gov (United States)

    Baçaoui, Abdelaziz; Dahbi, Abderrahman; Yaacoubi, Abdelrani; Bennouna, Chakib; Maldonado-Hódar, Francisco J; Rivera-Utrilla, José; Carrasco-Marín, Francisco; Moreno-Castilla, Carlos

    2002-09-01

    A series of seven activated carbons was obtained for use in drinking water treatments by steam-activation of olive-waste cakes. This raw material is an abundant and cheap waste byproduct of oil production, making these activated carbons economically feasible. The activated carbons, prepared by the one step method, were characterized, and the evolution of their characteristics (yield, adsorption capacities, and porosity) was analyzed as a function of the experimental parameters (activation temperature and activation time), using the Doehlert matrix. The Doehlert matrix allows the response surface to be studied with a good quality parameter estimation of the quadratic model. Each response has been described by a second order model that was adequate to predict responses in all experimental regions. The coefficients of the postulated model were calculated from the experimental responses by means of least squares regression, using the NEMROD software. We determined the region in which the optimum values of both activation temperature and activation time were achieved for the preparation of activated carbons suitable for use in water treatments. The "optimal activated carbon" was experimentally obtained, and its characteristic parameters showed a good agreement with those calculated from the model. The results obtained for activated carbons prepared by the one-step method were compared with those for activated carbons prepared by the two-step method. The characteristics of activated carbons obtained by the one-step and two-step methods showed that "one-step" activated carbons have a highly developed porous texture formed mainly of large macropores and micropores, whereas "two-step" activated carbons have a predominance of mesopores and narrow micropores. These activated carbons from olive-waste cakes showed a high capacity to adsorb herbicides (2,4-dichlorophenoxyacetic acid, 2,4-D; and 2-methyl, 4-chlorophenoxyacetic acid, MCPA) from water, with adsorption capacity

  8. Calorimetric properties of water and triacylglycerols in fern spores relating to storage at cryogenic temperatures.

    Science.gov (United States)

    Ballesteros, Daniel; Walters, Christina

    2007-08-01

    Storing spores is a promising method to conserve genetic diversity of ferns ex situ. Inappropriate water contents or damaging effects of triacylglycerol (TAG) crystallization may cause initial damage and deterioration with time in spores placed at -15 degrees C or liquid nitrogen temperatures. We used differential scanning calorimetry (DSC) to monitor enthalpy and temperature of water and TAG phase transitions within spores of five fern species: Pteris vittata, Thelypteris palustris, Dryopteris filix-mas, Polystichum aculeatum, Polystichum setiferum. The analyses suggested that these fern spores contained between 26% and 39% TAG, and were comprised of mostly oleic (P. vittata) or linoleic acid (other species) depending on species. The water contents at which water melting events were first observable ranged from 0.06 (P. vittata) to 0.12 (P. setiferum)gH(2)Og(-1)dry weight, and were highly correlated with water affinity parameters. In spores containing more than 0.09 (P. vittata) to 0.25 (P. setiferum)gH(2)Og(-1)dry weight, some water partitioned into a near pure water fraction that melted at about 0 degrees C. These sharp peaks near 0 degrees C were associated with lethal freezing treatments. The enthalpy of water melting transitions was similar in fern spores, pollen and seeds; however, the unfrozen water content was much lower in fern spores compared to other forms of germplasm. Though there is a narrow range of water contents appropriate for low temperature storage of fern spores, water content can be precisely manipulated to avoid both desiccation and freezing damage.

  9. A regional neural network model for predicting mean daily river water temperature

    Science.gov (United States)

    Wagner, Tyler; DeWeber, Jefferson Tyrell

    2014-01-01

    Water temperature is a fundamental property of river habitat and often a key aspect of river resource management, but measurements to characterize thermal regimes are not available for most streams and rivers. As such, we developed an artificial neural network (ANN) ensemble model to predict mean daily water temperature in 197,402 individual stream reaches during the warm season (May–October) throughout the native range of brook trout Salvelinus fontinalis in the eastern U.S. We compared four models with different groups of predictors to determine how well water temperature could be predicted by climatic, landform, and land cover attributes, and used the median prediction from an ensemble of 100 ANNs as our final prediction for each model. The final model included air temperature, landform attributes and forested land cover and predicted mean daily water temperatures with moderate accuracy as determined by root mean squared error (RMSE) at 886 training sites with data from 1980 to 2009 (RMSE = 1.91 °C). Based on validation at 96 sites (RMSE = 1.82) and separately for data from 2010 (RMSE = 1.93), a year with relatively warmer conditions, the model was able to generalize to new stream reaches and years. The most important predictors were mean daily air temperature, prior 7 day mean air temperature, and network catchment area according to sensitivity analyses. Forest land cover at both riparian and catchment extents had relatively weak but clear negative effects. Predicted daily water temperature averaged for the month of July matched expected spatial trends with cooler temperatures in headwaters and at higher elevations and latitudes. Our ANN ensemble is unique in predicting daily temperatures throughout a large region, while other regional efforts have predicted at relatively coarse time steps. The model may prove a useful tool for predicting water temperatures in sampled and unsampled rivers under current conditions and future projections of climate

  10. A regional neural network ensemble for predicting mean daily river water temperature

    Science.gov (United States)

    DeWeber, Jefferson Tyrell; Wagner, Tyler

    2014-09-01

    Water temperature is a fundamental property of river habitat and often a key aspect of river resource management, but measurements to characterize thermal regimes are not available for most streams and rivers. As such, we developed an artificial neural network (ANN) ensemble model to predict mean daily water temperature in 197,402 individual stream reaches during the warm season (May-October) throughout the native range of brook trout Salvelinus fontinalis in the eastern U.S. We compared four models with different groups of predictors to determine how well water temperature could be predicted by climatic, landform, and land cover attributes, and used the median prediction from an ensemble of 100 ANNs as our final prediction for each model. The final model included air temperature, landform attributes and forested land cover and predicted mean daily water temperatures with moderate accuracy as determined by root mean squared error (RMSE) at 886 training sites with data from 1980 to 2009 (RMSE = 1.91 °C). Based on validation at 96 sites (RMSE = 1.82) and separately for data from 2010 (RMSE = 1.93), a year with relatively warmer conditions, the model was able to generalize to new stream reaches and years. The most important predictors were mean daily air temperature, prior 7 day mean air temperature, and network catchment area according to sensitivity analyses. Forest land cover at both riparian and catchment extents had relatively weak but clear negative effects. Predicted daily water temperature averaged for the month of July matched expected spatial trends with cooler temperatures in headwaters and at higher elevations and latitudes. Our ANN ensemble is unique in predicting daily temperatures throughout a large region, while other regional efforts have predicted at relatively coarse time steps. The model may prove a useful tool for predicting water temperatures in sampled and unsampled rivers under current conditions and future projections of climate and land use

  11. Measurement of water activity from shales through thermo hygrometer

    Energy Technology Data Exchange (ETDEWEB)

    Rabe, Claudio [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo (GTEP)

    2004-07-01

    This paper presents a campaign of lab tests to obtain the water activity from shales and its pore fluid originated from offshore and onshore basin. The results of water activity from shales indicate that the values rang from 0.754 to 0.923 and for the pore fluid are between 0.987 and 0.940. The results show that the water activity of interstitial water can be obtained in 6 days and the rock in 10 days using the thermo hygrometer used. The degree of saturation, water content, kind and tenor of expansible and hydratable clay mineral, total and interconnected porosity, salinity of interstitial fluid and the capillary pressure of shale samples affected the results of water activity. (author)

  12. Development of method for the mineral water catalase activity determination

    Directory of Open Access Journals (Sweden)

    Olena М. Nikipelova

    2015-03-01

    Full Text Available Biological effects of mineral water depend not only on the chemical composition but also on the metabolic products of microbial cenosis. Among numerous microorganisms constituting the autochthonous microflora of mineral waters, we do evolve the saprophytic organisms producing the catalase, the saprophytes’ physiological and biological role being proven a long ago. The research aim was to develop a method for determination of mineral water catalase activity. Analyzed are various methods to determine the catalase activity in biological objects. Developed is a spectrophotometric method for determination of mineral water catalase activity. The method is efficiently tested with series of Ukrainian mineral waters. Calculated are the relative standard deviations which are significantly below normal errors, admitted at spectroscopic analysis and at the optic density range. The given method provides sufficient accuracy and convergence when estimating the mineral waters catalase activity, allowing to introduce a new index to assess the quality and biological value.

  13. Comparison of the Melting Temperatures of Classical and Quantum Water Potential Models

    Directory of Open Access Journals (Sweden)

    Sen Du

    2017-08-01

    Full Text Available As theoretical approaches and technical methods improve over time, the field of computer simulations for water has greatly progressed. Water potential models become much more complex when additional interactions and advanced theories are considered. Macroscopic properties of water predicted by computer simulations using water potential models are expected to be consistent with experimental outcomes. As such, discrepancies between computer simulations and experiments could be a criterion to comment on the performances of various water potential models. Notably, water can occur not only as liquid phases but also as solid and vapor phases. Therefore, the melting temperature related to the solid and liquid phase equilibrium is an effective parameter to judge the performances of different water potential models. As a mini review, our purpose is to introduce some water models developed in recent years and the melting temperatures obtained through simulations with such models. Moreover, some explanations referred to in the literature are described for the additional evaluation of the water potential models.

  14. Investigation of Neutron Detector Response to Varying Temperature and Water Content for Geothermal Applications

    Energy Technology Data Exchange (ETDEWEB)

    Akkurt, Hatice [ORNL

    2010-01-01

    Nuclear logging techniques have been used for oil well logging applications for decades. The basic principle is to use a neutron and/or photon source and neutron and photon detectors for characterization purposes. Although the technology has matured, it is not directly applicable to geothermal logging due to even more challenging environmental conditions, both in terms of temperature and pressure. For geothermal logging, the operating temperature can go up to 376 C for depths up to 10,000 km. In this paper, the preliminary computational results for thermal neutron detector response for varying temperature and water content for geothermal applications are presented. In this summary, preliminary results for neutron detector response for varying formation temperature and water content are presented. The analysis is performed for a steady state source (AmBe) and time dependent source (PNG) in pulsed mode. The computational results show significant sensitivity to water content as well as temperature changes for both steady state and time dependent measurements. As expected, the most significant change is due to the temperature change for S({alpha}, {beta}) nuclear data instead of individual isotope cross sections for the formation. Clearly, this is partially because of the fact that strong absorbers (i.e., chlorine) are not taken into account for the analysis at this time. The computational analysis was performed using the temperature dependent data in the ENDF/B-VII libraries, supplied with MCNP. Currently, the data for intermediate temperatures are being generated using NJOY and validated. A series of measurements are planned to validate the computational results. Further measurements are planned to determine the neutron and photon detector response as a function of temperature. The tests will be performed for temperatures up to 400 C.

  15. The effect of cloud liquid water on tropospheric temperature retrievals from microwave measurements

    Science.gov (United States)

    Bernet, Leonie; Navas-Guzmán, Francisco; Kämpfer, Niklaus

    2017-11-01

    Microwave radiometry is a suitable technique to measure atmospheric temperature profiles with high temporal resolution during clear sky and cloudy conditions. In this study, we included cloud models in the inversion algorithm of the microwave radiometer TEMPERA (TEMPErature RAdiometer) to determine the effect of cloud liquid water on the temperature retrievals. The cloud models were built based on measurements of cloud base altitude and integrated liquid water (ILW), all performed at the aerological station (MeteoSwiss) in Payerne (Switzerland). Cloud base altitudes were detected using ceilometer measurements while the ILW was measured by a HATPRO (Humidity And Temperature PROfiler) radiometer. To assess the quality of the TEMPERA retrieval when clouds were considered, the resulting temperature profiles were compared to 2 years of radiosonde measurements. The TEMPERA instrument measures radiation at 12 channels in the frequency range from 51 to 57 GHz, corresponding to the left wing of the oxygen emission line complex. When the full spectral information with all the 12 frequency channels was used, we found a marked improvement in the temperature retrievals after including a cloud model. The chosen cloud model influenced the resulting temperature profile, especially for high clouds and clouds with a large amount of liquid water. Using all 12 channels, however, presented large deviations between different cases, suggesting that additional uncertainties exist in the lower, more transparent channels. Using less spectral information with the higher, more opaque channels only also improved the temperature profiles when clouds where included, but the influence of the chosen cloud model was less important. We conclude that tropospheric temperature profiles can be optimized by considering clouds in the microwave retrieval, and that the choice of the cloud model has a direct impact on the resulting temperature profile.

  16. Low-temperature dielectric measurements of confined water in porous granites

    Science.gov (United States)

    Gonçalves da Silva, Hugo; Prezas, Pedro; Vinagre, Ana; Graça, Manuel F.; Monteiro, Jorge H.; Tlemçani, Mouhaydine; Moita, Patrícia; Pinho, António; Bezzeghoud, Mourad; Mendiratta, Sushil K.; Rosa, Rui N.

    2014-05-01

    Three different granitic rocks extracted from Évora (in the south of Portugal) where used to perform dielectric measurements in the frequency range from 100 Hz to 1 MHz and temperatures 100 - 350 K. Thin cylindrical samples were prepared and circular electrodes were established using silver conductive paint. A clear anomaly appears, for T ~ 200 - 220 K, in the dielectric measurements of the samples studied. This anomaly occurs in different materials and coincides with a phase transition of supercooled water. Tightly bounded water confined in the pores of the rock do not crystallize at 273 K, but form a metastable liquid down to 200 - 220 K increasing water polarization. Below this temperature water molecules solidify and polarizability decreases. The rock presenting the most sizeable anomaly has a very low specific surface area, ~ 0.09 m2g-1, and connected porosity, ~ 1.10 %. In addition, geochemical analyses reveal almost inexistence of water molecules in its structure confirming the role of confined water in the anomaly. Comparison between saturated, oven dried, and vacuum dried samples is done. Finally, a logarithmic dependency of the critical temperature for the supercooled water phase transition with the measuring frequency is found. The authors acknowledge the support of FCT (Portuguese Science and Technology Foundation) through the project PTDC/GEO-FIQ/4178/2012.

  17. Preparation and characterization of activated carbon from water ...

    African Journals Online (AJOL)

    Water hyacinth and water spinach were used as novel precursor materials for the production of powdered activated carbons. They were activated chemically with H3PO4, KOH, H2O2 pyrolyzed at 4500C and characterized in terms of pH, density, surface area, iodine number, porosity, ash content and moisture content.

  18. Molluscicidal activity of crude water leaf extracts of Alternanthera ...

    African Journals Online (AJOL)

    Administrator

    2007-02-19

    Feb 19, 2007 ... while the evaporated crude water extract had LC50 of 48.07 (42.81 – 54.28) for the dried leaf extract. For the fresh leaves the ... Key words: Alternanthera sesselis, crude water extract, molluscicidal activity, bioavailability, schistomiasis control. ... (Brown, 1980). Although the snails do not play an active.

  19. Antifungal activity of Comamonas acidovorans isolated from water ...

    African Journals Online (AJOL)

    Antifungal activity of Comamonas acidovorans isolated from water pond in south Jordan. ... A bacterial strain identified as Comamonas acidovorans NB-10II was isolated from water pond in South Jordan. It was found ... In batch culture, the active antimicrobial substances accumulated at the late growth cycle, reaching their

  20. New Construction and Catalyst Support Materials for Water Electrolysis at Elevated Temperatures

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey

    Proton exchange membrane (PEM) water electrolysis presents an attractive technology allowing to produce hydrogen for further use as a renewable energy source in the "Hydrogen cycle". Electrolysis of water steam at elevated temperatures has several advantages over the low temperature process....... However, at the same time it involves increased demands to dimensional and chemical stability of components against corrosion environment. Therefore, materials utilized in low temperature PEM electrolyzers cannot be used in systems operating above 100 °C and new candidates should be tested. The materials...... gives an introduction into the subject and Chapter 2 subsequently presents the theoretical background of the topic and describes techniques used to characterize catalysts and construction materials. Chapter 3 presents general principles and overview of materials used for PEM water electrolysis. Chapter...

  1. Responses of invertebrates to temperature and water stress: A polar perspective.

    Science.gov (United States)

    Everatt, Matthew J; Convey, Pete; Bale, Jeffrey S; Worland, M Roger; Hayward, Scott A L

    2015-12-01

    As small bodied poikilothermic ectotherms, invertebrates, more so than any other animal group, are susceptible to extremes of temperature and low water availability. In few places is this more apparent than in the Arctic and Antarctic, where low temperatures predominate and water is unusable during winter and unavailable for parts of summer. Polar terrestrial invertebrates express a suite of physiological, biochemical and genomic features in response to these stressors. However, the situation is not as simple as responding to each stressor in isolation, as they are often faced in combination. We consider how polar terrestrial invertebrates manage this scenario in light of their physiology and ecology. Climate change is also leading to warmer summers in parts of the polar regions, concomitantly increasing the potential for drought. The interaction between high temperature and low water availability, and the invertebrates' response to them, are therefore also explored. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Arbuscular mycorrhizae reducing water loss in maize plants under low temperature stress.

    Science.gov (United States)

    Zhu, Xian Can; Song, Feng Bin; Liu, Tie Dong; Liu, Sheng Qun

    2010-05-01

    Arbuscular mycorrhizal (AM) fungi form mutualistic mycorrhizal symbiotic associations with the roots of approximately 80% of all terrestrial plant species while facilitate the uptake of soil mineral nutrients by plants and in exchange obtain carbohydrates, thus representing a large sink for photosynthetically fixed carbon. Also, AM symbiosis increase plants resistance to abiotic stress such as chilling. In a recent study we reported that AM fungi improve low temperature stress in maize plants via alterations in host water status and photosynthesis. Here, the influence of AM fungus, Glomus etunicatum, on water loss rate and growth of maize plants was studied in pot culture under low temperature stress. The results indicated that low temperature stress significantly decreases the total fresh weight of maize plants, and AM symbiosis alleviate the water loss in leaves of maize plants.

  3. Water Resources Research program: nearshore currents and water temperatures in southwestern Lake Michigan. Progress report, June--December 1975

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, K.D.; Van Loon, L.S.

    1976-05-01

    Nearshore currents and water temperatures were measured almost continuously from June 23 through December 22, at five moorings in an array centered 4 km offshore of south Chicago. The mooring array was square, each side 1.6 km long. A current-meter mooring was placed at each corner, with one mooring in the center. One Bendix Q-15 current meter and one YSI temperature sensor were fixed to each mooring line. Each meter and associated temperature sensor was placed at middepth; the water depth averaged about 12 m. The following types of graphs are presented for current and wind observations: (1) U, V flow components versus time, (2) specific kinetic energy versus time, (3) flow speeds and directions versus time, (4) composite velocity histograms and associated U, V-component histograms, and (5) progressive-vector diagrams. Also presented are listings of the component programs used to reduce the data. Currents in the region were dominantly shore-parallel. Water temperatures reflected several episodes of upwelling and downwelling. Detailed analyses of the data will be presented in subsequent reports.

  4. The influence of natural mineral water on aquaporin water permeability and human natural killer cell activity.

    Science.gov (United States)

    Kitagawa, Yoshichika; Liu, Chengwei; Ding, Xiaodong

    2011-05-27

    Aquaporins are the intrinsic membrane proteins functioning as water channel to transport water and/or mineral nutrients across the biological membrane systems. In this research, we aimed to clarify if the selected mineral water can affect aquaporin functions in vitro and the assumption of the mineral water can modify aquaporin expression and activate natural killer cell activity in human body. First, we expressed six human and eight plant aquaporin genes in oocytes and compared the effect of different kinds of natural mineral water on aquaporin activity. The oocyte assay data show that Hita tenryosui water could promote water permeability of almost all human and plant aquaporins in varying degrees, and freeze-dry and organic solvent extraction could reduce AQP2 activity but pH change and boiling could not. Second, each volunteer in two groups (10 in one group) received an oral Hita tenryosui or tap water load of 1000 ml/day for total four weeks. We found that these two kinds of water did not directly affect the relative expression levels of AQP1 and AQP9 in the blood cells, but intriguingly, the natural killer cell activities of the volunteers drinking Hita tenryosui water were significantly improved, suggesting that Hita tenryosui water has obvious health function, which opens a new and interesting field of investigation related to the link between mineral water consumption and human health and the therapies for some chronic diseases. Published by Elsevier Inc.

  5. Seawater Temperature and Wind Speed Dependences and Diurnal Variation of Ambient Noise at the Snapping Shrimp Colony in Shallow Water of Southern Sea of Korea

    Science.gov (United States)

    Jung, Seom-Kyu; Choi, Bok Kyoung; Kim, Bong-Chae; Kim, Byoung-Nam; Kim, Seong Hyeon; Park, Yosup; Lee, Yong-Kuk

    2012-07-01

    The seawater temperature and wind dependences and diurnal variation of the ambient noise at the snapping shrimp colony in shallow water of the southern sea of Korea were investigated. The ambient noise levels are significantly affected by the snapping shrimp sound, when the bottom seawater temperature increases and the wind speed decreases. However, they are not exceptively almost affected by the snapping shrimp sound when the wind speed decreases at low seawater temperatures (shrimp sound in the morning and night time zones. This study shows that the activity of the snapping shrimp affecting the variation in ambient noise level in shallow water can be related to the wind speed as well as the seawater temperature. This study also shows that the snapping shrimp in diurnal activity can be more active in the morning and night time zones.

  6. Reef core insights into mid-Holocene water temperatures of the southern Great Barrier Reef

    Science.gov (United States)

    Sadler, James; Webb, Gregory E.; Leonard, Nicole D.; Nothdurft, Luke D.; Clark, Tara R.

    2016-10-01

    The tropical and subtropical oceans of the Southern Hemisphere are poorly represented in present-day climate models, necessitating an increased number of paleoclimate records from this key region to both understand the Earth's climate system and help constrain model simulations. Here we present a site-specific calibration of live collected massive Porites Sr/Ca records against concomitant in situ instrumental water temperature data from the fore-reef slope of Heron Reef, southern Great Barrier Reef (GBR). The resultant calibration, and a previously published Acropora calibration from the same site, was applied to subfossil coral material to investigate Holocene water temperatures at Heron Reef. U-Th-dated samples of massive Porites suggest cooler water temperatures with reduced seasonal amplitude at 5.2 ka (2.76-1.31°C cooler than present) and 7 ka (1.26°C cooler than present) at Heron Reef. These results contrast the previous suggestion of a mid-Holocene Thermal Maximum in the central GBR around 5.35 ka and 4.48 ka, yet may be explained by differences in temperature of the shallow ponded reef flat (central GBR) and the deeper reef slope waters (this study) and potential large reservoir correction errors associated with early radiocarbon dates. Combining coral-based water temperature anomaly reconstructions from the tropical and subtropical western Pacific indicates a coherent temperature response across the meridional gradient from Indonesia and Papua New Guinea down to the southern GBR. This similarity in reconstructed temperature anomalies suggests a high probability of an earlier expression of a mid-Holocene Thermal Maximum on the GBR between 6.8 and 6.0 ka.

  7. Physicochemical effect of activation temperature on the sorption properties of pine shell activated carbon.

    Science.gov (United States)

    Wasim, Agha Arslan; Khan, Muhammad Nasiruddin

    2017-03-01

    Activated carbons produced from a variety of raw materials are normally selective towards a narrow range of pollutants present in wastewater. This study focuses on shifting the selectivity of activated carbon from inorganic to organic pollutants using activation temperature as a variable. The material produced from carbonization of pine shells substrate was activated at 250°C and 850°C. Both adsorbents were compared with commercial activated carbon for the sorption of lead, cadmium, methylene blue, methyl blue, xylenol orange, and crystal violet. It was observed that carbon activated at 250°C was selective for lead and cadmium whereas the one activated at 850°C was selective for the organic dyes. The Fourier transform infrared spectroscopy study revealed that AC850 had less surface functional groups as compared to AC250. Point of zero charge and point of zero salt effect showed that AC250 had acidic groups at its surface. Scanning electron microscopy depicted that increase in activation temperature resulted in an increase in pore size of activated carbon. Both AC250 and AC850 followed pseudo-second-order kinetics. Temkin isotherm model was a best fit for empirical data obtained at equilibrium. The model also showed that sorption process for both AC250 and AC850 was physisorption.

  8. Energy Efficiency of Low-Temperature Deaeration of Makeup Water for a District Heating System

    Energy Technology Data Exchange (ETDEWEB)

    Sharapov, V. I., E-mail: vlad-sharapov2008@yandex.ru; Kudryavtseva, E. V. [Ulyanovsk State Technical University (Russian Federation)

    2016-07-15

    It is shown that the temperature of makeup water in district heating systems has a strong effect on the energy efficiency of turbines of thermal power plants. A low-temperature deaeration process that considerably improves the energy efficiency of thermal power plants is developed. The desorbing agent is the gas supplied to the burners of the boiler. The energy efficiency of the process for a typical unit of thermal power plant is assessed.

  9. Sea-ice cover in the Nordic Seas and the sensitivity to Atlantic water temperatures

    Science.gov (United States)

    Jensen, Mari F.; Nisancioglu, Kerim H.; Spall, Michael A.

    2017-04-01

    Changes in the sea-ice cover of the Nordic Seas have been proposed to play a key role for the dramatic temperature excursions associated with the Dansgaard-Oeschger events during the last glacial. However, with its proximity to the warm Atlantic water, how a sea-ice cover can persist in the Nordic Seas is not well understood. In this study, we apply an eddy-resolving configuration of the Massachusetts Institute of Technology general circulation model with an idealized topography to study the presence of sea ice in a Nordic Seas-like domain. We assume an infinite amount of warm Atlantic water present in the south by restoring the southern area to constant temperatures. The sea-surface temperatures are restored toward cold, atmospheric temperatures, and as a result, sea ice is present in the interior of the domain. However, the sea-ice cover in the margins of the Nordic Seas, an area with a warm, cyclonic boundary current, is sensitive to the amount of heat entering the domain, i.e., the restoring temperature in the south. When the temperature of the warm, cyclonic boundary current is high, the margins are free of sea ice and heat is released to the atmosphere. We show that with a small reduction in the temperature of the incoming Atlantic water, the Nordic Seas-like domain is fully covered in sea ice. Warm water is still entering the Nordic Seas, however, this happens at depths below a cold, fresh surface layer produced by melted sea ice. Consequently, the heat release to the atmosphere is reduced along with the eddy heat fluxes. Results suggest a threshold value in the amount of heat entering the Nordic Seas before the sea-ice cover disappears in the margins. We study the sensitivity of this threshold to changes in atmospheric temperatures and vertical diffusivity.

  10. Mosquito breeding site water temperature observations and simulations towards improved vector-borne disease models for Africa

    Directory of Open Access Journals (Sweden)

    Ernest O. Asare

    2016-03-01

    Full Text Available An energy budget model is developed to predict water temperature of typical mosquito larval developmental habitats. It assumes a homogeneous mixed water column driven by empirically derived fluxes. The model shows good agreement at both hourly and daily time scales with 10-min temporal resolution observed water temperatures, monitored between June and November 2013 within a peri-urban area of Kumasi, Ghana. There was a close match between larvae development times calculated using either the model-derived or observed water temperatures. The water temperature scheme represents a significant improvement over assuming the water temperature to be equal to air temperature. The energy budget model requires observed minimum and maximum temperatures, information that is generally available from weather stations. Our results show that hourly variations in water temperature are important for the simulation of aquatic-stage development times. By contrast, we found that larval development is insensitive to sub-hourly variations. Modelling suggests that in addition to water temperature, accurate estimation of degree-day development time is very important to correctly predict the larvae development times. The results highlight the potential of the model to predict water temperature of temporary bodies of surface water. Our study represents an important contribution towards the improvement of weatherdriven dynamical disease models, including those designed for malaria early forecasting systems.

  11. Mosquito breeding site water temperature observations and simulations towards improved vector-borne disease models for Africa.

    Science.gov (United States)

    Asare, Ernest O; Tompkins, Adrian M; Amekudzi, Leonard K; Ermert, Volker; Redl, Robert

    2016-03-31

    An energy budget model is developed to predict water temperature of typical mosquito larval developmental habitats. It assumes a homogeneous mixed water column driven by empirically derived fluxes. The model shows good agreement at both hourly and daily time scales with 10-min temporal resolution observed water temperatures, monitored between June and November 2013 within a peri-urban area of Kumasi, Ghana. There was a close match between larvae development times calculated using either the model-derived or observed water temperatures. The water temperature scheme represents a significant improvement over assuming the water temperature to be equal to air temperature. The energy budget model requires observed minimum and maximum temperatures, information that is generally available from weather stations. Our results show that hourly variations in water temperature are important for the simulation of aquatic-stage development times. By contrast, we found that larval development is insensitive to sub-hourly variations. Modelling suggests that in addition to water temperature, accurate estimation of degree-day development time is very important to correctly predict the larvae development times. The results highlight the potential of the model to predict water temperature of temporary bodies of surface water. Our study represents an important contribution towards the improvement of weatherdriven dynamical disease models, including those designed for malaria early forecasting systems.

  12. Experimental Investigation of a Mechanical Vapour Compression Chiller at Elevated Chilled Water Temperatures

    KAUST Repository

    Thu, Kyaw

    2017-05-18

    The performance of a Mechanical Vapour Compression (MVC) chiller is experimentally investigated under operating conditions suitable for sensible cooling. With the emergence of the energy efficient dehumidification systems, it is possible to decouple the latent load from the MVC chillers which can be operated at higher chilled water temperature for handling sensible cooling load. In this article, the performance of the chiller is evaluated at the elevated chilled water outlet temperatures (7 – 17° C) at various coolant temperatures (28 – 32° C) and flow rates (ΔT = 4 and 5° C) for both full- and part-load conditions. Keeping the performance at the AHRI standard as the baseline condition, the efficacy of the chiller in terms of compression ratio, cooling capacity and COP at aforementioned conditions is quantified experimentally. It is observed that for each one-degree Celsius increase in the chilled water temperature, the COP of the chiller improves by about 3.5% whilst the cooling capacity improvement is about 4%. For operation at 17° C chilled water outlet temperature, the improvements in COP and cooling capacity are between 37 – 40% and 40 – 45%, respectively, compared to the performance at the AHRI standards. The performance of the MVC chiller at the abovementioned operation conditions is mapped on the chiller performance characteristic chart.

  13. Interactive Effect of Air-Water Ratio and Temperature on the Air Stripping of Benzene

    Directory of Open Access Journals (Sweden)

    M. E. Abdullahi

    2014-06-01

    Full Text Available High cost of pilot scale studies has led engineers to use simulation to study the factors that affect process performance. This study focuses on the interactive effect of air water ratio and temperature on the removal of volatile organic compounds from polluted water using packed column air stripper taking benzene as a case study. The process governing equations developed based on two-film model of mass transfer were solved using MATLAB and a surface response plot was done. The mass transfer coefficient increased from 0.1237x10-5 to 0.1932x10-5 s-1 as the temperature was raised from 293 to 323 K. Also, the Henry’s constant increased from 228.59 to 883.36 K as the temperature was raised from 293 to 323 K. Benzene removal efficiencies of over 99% were obtained for all combinations of temperature and air-water ratio. The result also indicated that air stripping of benzene from wastewater is most dependent on temperature and moderately on air-water ratio.

  14. Wall sticking of high water-cut crude oil transported at temperatures below the gel point

    Science.gov (United States)

    Zheng, Haimin; Huang, Qiyu; Wang, Changhui

    2015-12-01

    Some high water-cut crude oils can flow in the temperature below the oil gel point, while oil particles may adhere to the pipe wall as paste; this process is known as ‘wall sticking’. This can cause partial or even total blocking of the transportation pipe. Several experiments using a laboratory flow loop were conducted to study the wall sticking characteristics of high water-cut crude oils. The experimental results indicated that the predominant influencing factors of wall sticking included shear stress, water-cut and differences between gel point and wall temperature. The wall sticking rate and occurrence temperature decrease with the increase of water-cut and shear stress. The criterion for the wall sticking occurrence temperature (WSOT), and the regression formula of the wall sticking thickness for high water-cut crude oil were then established. Typical case studies indicated that the prediction results obtained from the WSOT criterion and the wall sticking thickness regression formula were in accordance with the measured values. The wall sticking rate and WSOT vary widely under different conditions and it is necessary to consider its non-uniformity in production.

  15. Acrylic resin water sorption under different pressure, temperature and time conditions

    Directory of Open Access Journals (Sweden)

    Rizzatti-Barbosa Célia Marisa

    2001-01-01

    Full Text Available The purpose of this work was to analyze water sorption by polymerized acrylic resins under different pressure, temperature and time treatments. A thermo-cured acrylic resin was used as the denture base (Classico Ltda. and ethylene glycol di-methacrylate as a cross-linking agent, with processing carried out in a water bath at 73 °C for nine hours. Forty-five samples were prepared following the criteria and dimensions of specification # 12 of the American Dental Association (ADA, using a matrix in the shape of a stainless steel disc with 50 ± 1 mm diameter and 0.5 ± 0.05 mm thickness. The control group samples were stored in distilled water for 30 days, while groups GII to GIX were placed in a polymerization device with adjustable pressure, time and temperature. An analysis of the variance of the results revealed the influence of different factors on water sorption only, with significant factors being temperature, time, pressure and the interaction between time and temperature. Other interactions exerted no significant influence on water sorption. Neither additional treatments nor the control group (GI showed any significant difference in comparison to the averages of other treatments.

  16. Excystation of Cryptosporidium parvum at temperatures that are reached during solar water disinfection.

    Science.gov (United States)

    Gómez-Couso, H; Fontán-Sainz, M; Fernández-Alonso, J; Ares-Mazás, E

    2009-04-01

    Species belonging to the genera Cryptosporidium are recognized as waterborne pathogens. Solar water disinfection (SODIS) is a simple method that involves the use of solar radiation to destroy pathogenic microorganisms that cause waterborne diseases. A notable increase in water temperature and the existence of a large number of empty or partially excysted (i.e. unviable) oocysts have been observed in previous SODIS studies with water experimentally contaminated with Cryptosporidium parvum oocysts under field conditions. The aim of the present study was to evaluate the effect of the temperatures that can be reached during exposure of water samples to natural sunlight (37-50 degrees C), on the excystation of C. parvum in the absence of other stimuli. In samples exposed to 40-48 degrees C, a gradual increase in the percentage of excystation was observed as the time of exposure increased and a maximum of 53.81% of excystation was obtained on exposure of the water to a temperature of 46 degrees C for 12 h (versus 8.80% initial isolate). Under such conditions, the oocyst infectivity evaluated in a neonatal murine model decreased statistically with respect to the initial isolate (19.38% versus 100%). The results demonstrate the important effect of the temperature on the excystation of C. parvum and therefore on its viability and infectivity.

  17. Enzyme catalysis in organic solvents: influence of water content, solvent composition and temperature on Candida rugosa lipase catalyzed transesterification.

    Science.gov (United States)

    Herbst, Daniela; Peper, Stephanie; Niemeyer, Bernd

    2012-12-31

    In the present study the influence of water content, solvent composition and reaction temperature on the transesterification of 1-phenylpropan-2-ol catalyzed by Candida rugosa lipase was examined. Reactions were carried out in different mixtures of hexane and tetrahydrofurane. The studies showed that an increasing water content of the organic solvent results in an increasing enzyme activity and a decreasing enantiomeric excess. Furthermore, a significant influence of the solvent hydrophilicity both on the enzyme activity and on the enantiomeric excess was found. An increase in solvent hydrophilicity leads to a decrease of enzyme activity and an increase of the enantiomeric excess. This indicates that the enzyme becomes more selective with decreasing flexibility. Similar effects were found by variation of the reaction temperature. Taken together, the decrease in conversion and the increase in selectivity with increasing solvent hydrophilicity are induced by the different water contents on the enzyme surface and not by the solvent itself. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. High temperature active heat exchanger research for latent heat storage

    Science.gov (United States)

    Alario, J.; Haslett, R.

    1982-02-01

    An active heat exchange method in a latent heat (salt) thermal energy storage system that prevents a low conductivity solid salt layer from forming on heat transfer surfaces was developed. An evaluation of suitable media with melting points in the temperature range of interest (250 to 400 C) limited the candidates to molten salts from the chloride, hydroxide and nitrate families, based on high storage capacity, good corrosion characteristics and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a choride eutectic (20.5KCL o 24.5NaCL o 55.MgCl2% by wt.), with a nominal melting point of 385 C. Various active heat exchange concepts were given a technical and economic comparison to a passive tube shell design for a reference application (300 MW sub t for 6 hours). Test hardware was then built for the most promising concept: a direct contact heat exchanger in which molten salt droplets are injected into a cooler counter flowing stream of liquid metal carrier fluid (lead/Bismuth).

  19. The Effect of Water Temperature during Cold-Water Immersion on Recovery from Exercise-Induced Muscle Damage.

    Science.gov (United States)

    Vieira, A; Siqueira, A F; Ferreira-Junior, J B; do Carmo, J; Durigan, J L Q; Blazevich, A; Bottaro, M

    2016-11-01

    This study investigated the effects of 5 and 15°C cold-water immersion on recovery from exercise resulting in exercise-induced muscle damage. 42 college-aged men performed 5×20 drop-jumps and were randomly allocated into one of 3 groups: (1) 5°C; (2) 15°C; or (3) control. After exercise, individuals from the cold-water immersion groups had their lower limbs immerged in iced water for 20 min. Isometric knee extensor torque, countermovement jump, muscle soreness, and creatine kinase were measured before, immediately after, 24, 48, 72, 96 and 168 h post-exercise. There was no between-group difference in isometric strength recovery (p=0.73). However, countermovement jump recovered quicker in cold-water immersion groups compared to control group (pcold-water immersion promote recovery of stretch-shortening cycle performance, but not influence the recovery of maximal contractile force. Immersion at warmer temperature may be more effective than colder temperatures promoting recovery from strenuous exercise. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Observation of temperature and pH during biogas production from water hyacinth and cow manure

    Directory of Open Access Journals (Sweden)

    Nurfitri Astuti

    2013-11-01

    Full Text Available Biogas is generated from biological process of organic material by bacterial engaged. Biogas can be derived from manure, municipal waste, agricultural waste and other biomass resources. In addition to the use of cow manure as raw material for biogas production, it can also be derived from biomass containing cellulose which one is water hyacinth as an organic material that contains quite large cellulose. The abundance of water hyacinth found in Rawapening causing several negative impacts. The purpose of this study is to observe  temperature and pH on the biogas production generated from water hyacinth of Rawapening and cow manure. Biogas production process begins by chopping the leaves and stems of water hyacinth, and then mixed with cow manure and water. The results of substrate variation of water hyacinth, cow manure and water reaches optimally at 40:80:480 respectively, which produce the highest point of  biogas amounted 176.33 ml on the day 20 in 1L sized digester, the temperature of the biogas production is at 32°C.  At the initial fermentation, digester temperature of 30°C has increased over the course of the fermentation process, a peak at day 20 and then decreased to 27°C at the end of fermentation. There is a decrease in pH starting from initial fermentation at pH 6-7 and then the pH began to decline until the end of fermentation as amount of pH 5.Doi: http://dx.doi.org/10.12777/wastech.1.1.22-25Citation:  Nurfitri Astuti, N., Tri Retnaningsih Soeprobowati, T.R., and  Budiyono. 2013. Observation of temperature and pH during biogas production from water hyacinth and cow manure. Waste Technology 1(1:1-5. Doi: http://dx.doi.org/10.12777/wastech.1.1.22-25

  1. Water Intake by Outdoor Temperature Among Children Aged 1-10 Years: Implications for Community Water Fluoridation in the U.S.

    Science.gov (United States)

    Beltrán-Aguilar, Eugenio D; Barker, Laurie; Sohn, Woosung; Wei, Liang

    2015-01-01

    The U.S. water fluoridation recommendations, which have been in place since 1962, were based in part on findings from the 1950s that children's water intake increased with outdoor temperature. We examined whether or not water intake is associated with outdoor temperature. Using linked data from the National Health and Nutrition Examination Survey (NHANES) 1999-2004 and the National Oceanic and Atmospheric Administration, we examined reported 24-hour total and plain water intake in milliliters per kilogram of body weight per day of children aged 1-10 years by maximum outdoor temperature on the day of reported water intake, unadjusted and adjusted for age, sex, race/ethnicity, and poverty status. We applied linear regression methods that were used in previously reported analyses of data from NHANES 1988-1994 and from the 1950s. We found that total water intake was not associated with temperature. Plain water intake was weakly associated with temperature in unadjusted (coefficient 5 0.2, p=0.015) and adjusted (coefficient 5 0.2, p=0.013) linear regression models. However, these models explained little of the individual variation in plain water intake (unadjusted: R(2)=0.005; adjusted: R(2)=0.023). Optimal fluoride concentration in drinking water to prevent caries need not be based on outdoor temperature, given the lack of association between total water intake and outdoor temperature, the weak association between plain water intake and outdoor temperature, and the minimal amount of individual variance in plain water intake explained by outdoor temperature. These findings support the change in the U.S. Public Health Service recommendation for fluoride concentration in drinking water for the prevention of dental caries from temperature-related concentrations to a single concentration that is not related to outdoor temperature.

  2. Water Intake by Outdoor Temperature Among Children Aged 1–10 Years: Implications for Community Water Fluoridation in the U.S.

    Science.gov (United States)

    Beltrán-Aguilar, Eugenio D.; Sohn, Woosung; Wei, Liang

    2015-01-01

    Objective The U.S. water fluoridation recommendations, which have been in place since 1962, were based in part on findings from the 1950s that children's water intake increased with outdoor temperature. We examined whether or not water intake is associated with outdoor temperature. Methods Using linked data from the National Health and Nutrition Examination Survey (NHANES) 1999–2004 and the National Oceanic and Atmospheric Administration, we examined reported 24-hour total and plain water intake in milliliters per kilogram of body weight per day of children aged 1–10 years by maximum outdoor temperature on the day of reported water intake, unadjusted and adjusted for age, sex, race/ethnicity, and poverty status. We applied linear regression methods that were used in previously reported analyses of data from NHANES 1988–1994 and from the 1950s. Results We found that total water intake was not associated with temperature. Plain water intake was weakly associated with temperature in unadjusted (coefficient 5 0.2, p=0.015) and adjusted (coefficient 5 0.2, p=0.013) linear regression models. However, these models explained little of the individual variation in plain water intake (unadjusted: R2=0.005; adjusted: R2=0.023). Conclusion Optimal fluoride concentration in drinking water to prevent caries need not be based on outdoor temperature, given the lack of association between total water intake and outdoor temperature, the weak association between plain water intake and outdoor temperature, and the minimal amount of individual variance in plain water intake explained by outdoor temperature. These findings support the change in the U.S. Public Health Service recommendation for fluoride concentration in drinking water for the prevention of dental caries from temperature-related concentrations to a single concentration that is not related to outdoor temperature. PMID:26346578

  3. Water-resources activities in Florida, 1988-89

    Science.gov (United States)

    Glenn, Mildred E.

    1989-01-01

    This report contains summary statements of water resources activities in Florida conducted by the Water Resources Division of the U.S. Geological Survey in cooperation with Federal, State , and local agencies during 1988. These activities are part of the Federal program of appraising the Nation 's water resources. Included are brief descriptions of the nature and scope of all active studies, summaries of significant results for 1988 and anticipated accomplishments during 1989. Water resources appraisals in Florida are highly diversified, ranging from hydrologic records networks to interpretive appraisals of water resources and applied research to develop investigative techniques. Thus, water-resources investigations range from basic descriptive water-availability studies for areas of low-intensity water development and management to sophisticated cause and effect studies in areas of high-intensity water development and management. The interpretive reports and records that are products of the investigations are a principal hydrologic foundation upon which the plans for development, management, and protection of Florida 's water resources may be used. Water data and information required to implement sound water-management programs in highly urbanized areas relate to the quantity and quality of storm runoff, sources of aquifer contamination, injection of wastes into deep strata, underground storage of freshwater, artificial recharge of aquifers, environmental effects of reuse of water, and effects of land development on changes in ground-and surface-water quality. In some parts of the State broad areas are largely rural. Future growth is anticipated in many of these. This report is intended to inform those agencies vitally interested in the water resources of Florida as to the current status and objectives of the U.S. Geological Survey cooperative program. The mission of this program is to collect, interpret, and publish information on water resources. Almost all of

  4. Temperatures in a runaway greenhouse on the evolving Venus Implications for water loss

    Science.gov (United States)

    Watson, A. J.; Donahue, T. M.; Kuhn, W. R.

    1984-01-01

    Some aspects of the temperature structure of a runaway greenhouse on Venus are examined using one-dimensional radiative transfer techniques. It is found that there generally is a region high in the atmosphere where condensation and cloud formation can occur, while deep in the atmosphere the gas is strongly unsaturated with respect to water vapor. The necessity of including clouds introduces considerably uncertainty into the calculation of surface temperatures. Under reasonable assumptions concerning the clouds, temperatures deep in the atmosphere are high enough to produce a plastic or even molten surface, which may significantly ease the problem of explaining the loss of oxygen.

  5. Sub-Microsecond Temperature Measurement in Liquid Water Using Laser Induced Thermal Acoustics

    Science.gov (United States)

    Alderfer, David W.; Herring, G. C.; Danehy, Paul M.; Mizukaki, Toshiharu; Takayama, Kazuyoshi

    2005-01-01

    Using laser-induced thermal acoustics, we demonstrate non-intrusive and remote sound speed and temperature measurements over the range 10 - 45 C in liquid water. Averaged accuracy of sound speed and temperature measurements (10 s) are 0.64 m/s and 0.45 C respectively. Single-shot precisions based on one standard deviation of 100 or greater samples range from 1 m/s to 16.5 m/s and 0.3 C to 9.5 C for sound speed and temperature measurements respectively. The time resolution of each single-shot measurement was 300 nsec.

  6. Distributed Temperature Sensing - a Useful Tool for Investigation of Surface Water - Groundwater Interaction

    Science.gov (United States)

    Vogt, T.; Hahn-Woernle, L.; Sunarjo, B.; Thum, T.; Schneider, P.; Schirmer, M.; Cirpka, O. A.

    2009-04-01

    In recent years, the transition zone between surface water bodies and groundwater, known as the hyporheic zone, has been identified as crucial for the ecological status of the open-water body and the quality of groundwater. The hyporheic exchange processes vary both in time and space. For the assessment of water quality of both water bodies reliable models and measurements of the exchange rates and their variability are needed. A wide range of methods and technologies exist to estimate water fluxes between surface water and groundwater. Due to recent developments in sensor techniques and data logging work on heat as a tracer in hydrological systems advances, especially with focus on surface water - groundwater interactions. Here, we evaluate the use of Distributed Temperature Sensing (DTS) for the qualitative and quantitative investigation of groundwater discharge into and groundwater recharge from a river. DTS is based on the temperature dependence of Raman scattering. Light from a laser pulse is scattered along an optical fiber of up to several km length, which is the sensor of the DTS system. By sampling the the back-scattered light with high temporal resolution, the temperature along the fiber can be measured with high accuracy (0.1 K) and high spatial resolution (1 m). We used DTS at a test side at River Thur in North-East Switzerland. Here, the river is loosing and the aquifer is drained by two side-channels, enabling us to test DTS for both, groundwater recharge from the river and groundwater discharge into the side-channels. For estimation of seepage rates, we measured highly resolved vertical temperature profiles in the river bed. For this application, we wrapped an optical fiber around a piezometer tube and measured the temperature distribution along the fiber. Due to the wrapping, we obtained a vertical resolution of approximately 5 mm. We analyzed the temperature time series by means of Dynamic Harmonic Regression as presented by Keery et al. (2007

  7. Temperature and UV light affect the activity of marine cell-free enzymes

    Directory of Open Access Journals (Sweden)

    B. Thomson

    2017-09-01

    Full Text Available Microbial extracellular enzymatic activity (EEA is the rate-limiting step in the degradation of organic matter in the oceans. These extracellular enzymes exist in two forms: cell-bound, which are attached to the microbial cell wall, and cell-free, which are completely free of the cell. Contrary to previous understanding, cell-free extracellular enzymes make up a substantial proportion of the total marine EEA. Little is known about these abundant cell-free enzymes, including what factors control their activity once they are away from their sites (cells. Experiments were run to assess how cell-free enzymes (excluding microbes respond to ultraviolet radiation (UVR and temperature manipulations, previously suggested as potential control factors for these enzymes. The experiments were done with New Zealand coastal waters and the enzymes studied were alkaline phosphatase (APase, β-glucosidase, (BGase, and leucine aminopeptidase (LAPase. Environmentally relevant UVR (i.e. in situ UVR levels measured at our site reduced cell-free enzyme activities by up to 87 % when compared to controls, likely a consequence of photodegradation. This effect of UVR on cell-free enzymes differed depending on the UVR fraction. Ambient levels of UV radiation were shown to reduce the activity of cell-free enzymes for the first time. Elevated temperatures (15 °C increased the activity of cell-free enzymes by up to 53 % when compared to controls (10 °C, likely by enhancing the catalytic activity of the enzymes. Our results suggest the importance of both UVR and temperature as control mechanisms for cell-free enzymes. Given the projected warming ocean environment and the variable UVR light regime, it is possible that there could be major changes in the cell-free EEA and in the enzymes contribution to organic matter remineralization in the future.

  8. Temperature and UV light affect the activity of marine cell-free enzymes

    Science.gov (United States)

    Thomson, Blair; Hepburn, Christopher David; Lamare, Miles; Baltar, Federico

    2017-09-01

    Microbial extracellular enzymatic activity (EEA) is the rate-limiting step in the degradation of organic matter in the oceans. These extracellular enzymes exist in two forms: cell-bound, which are attached to the microbial cell wall, and cell-free, which are completely free of the cell. Contrary to previous understanding, cell-free extracellular enzymes make up a substantial proportion of the total marine EEA. Little is known about these abundant cell-free enzymes, including what factors control their activity once they are away from their sites (cells). Experiments were run to assess how cell-free enzymes (excluding microbes) respond to ultraviolet radiation (UVR) and temperature manipulations, previously suggested as potential control factors for these enzymes. The experiments were done with New Zealand coastal waters and the enzymes studied were alkaline phosphatase (APase), β-glucosidase, (BGase), and leucine aminopeptidase (LAPase). Environmentally relevant UVR (i.e. in situ UVR levels measured at our site) reduced cell-free enzyme activities by up to 87 % when compared to controls, likely a consequence of photodegradation. This effect of UVR on cell-free enzymes differed depending on the UVR fraction. Ambient levels of UV radiation were shown to reduce the activity of cell-free enzymes for the first time. Elevated temperatures (15 °C) increased the activity of cell-free enzymes by up to 53 % when compared to controls (10 °C), likely by enhancing the catalytic activity of the enzymes. Our results suggest the importance of both UVR and temperature as control mechanisms for cell-free enzymes. Given the projected warming ocean environment and the variable UVR light regime, it is possible that there could be major changes in the cell-free EEA and in the enzymes contribution to organic matter remineralization in the future.

  9. Translational diffusion of water and its dependence on temperature in charged and uncharged clays: A neutron scattering study.

    Science.gov (United States)

    González Sánchez, Fátima; Jurányi, Fanni; Gimmi, Thomas; Van Loon, Luc; Unruh, Tobias; Diamond, Larryn W

    2008-11-07

    The water diffusion in four different, highly compacted clays [montmorillonite in the Na- and Ca-forms, illite in the Na- and Ca-forms, kaolinite, and pyrophyllite (bulk dry density rho(b)=1.85+/-0.05 gcm(3))] was studied at the atomic level by means of quasielastic neutron scattering. The experiments were performed on two time-of-flight spectrometers and at three different energy resolutions [FOCUS at SINQ, PSI (3.65 and 5.75 A), and TOFTOF at FRM II (10 A)] for reliable data analysis and at temperatures between 27 and 95 degrees C. Two different jump diffusion models were used to describe the translational motion. Both models describe the data equally well and give the following ranking of diffusion coefficients: Na-montmorilloniteclays had slightly larger diffusion coefficients than that of bulk water due to their hydrophobic surfaces. The time between jumps, tau(t), follows the sequence: Ca-montmorillonite>or=Na-montmorillonite>Ca-illite>Na-illite>or=kaolinite>pyrophyllite>or=water, in both jump diffusion models. For clays with a permanent layer charge (montmorillonite and illite) a reduction in the water content by a factor of 2 resulted in a decrease in the self-diffusion coefficients and an increase in the time between jumps as compared to the full saturation. The uncharged clay kaolinite exhibited no change in the water mobility between the two hydration states. The rotational relaxation time of water was affected by the charged clay surfaces, especially in the case of montmorillonite; the uncharged clays presented a waterlike behavior. The activation energies for translational diffusion were calculated from the Arrhenius law, which adequately describes the systems in the studied temperature range. Na- and Ca-montmorillonite (approximately 11-12 kJmol), Na-illite (approximately 13 kJmol), kaolinite and pyrophyllite (approximately 14 kJmol), and Ca-illite (approximately 15 kJmol) all had lower activation energies than bulk water (approximately 17 kJmol in

  10. The effects of activation temperature on physico-chemical characteristics of activated carbons derived from biomass wastes

    Science.gov (United States)

    Sutrisno, Bachrun; Hidayat, Arif

    2015-12-01

    This research focused on investigating in the effect of activation temperature on the physico-chemical properties of palm empty fruit bunch (PEFB) based activated carbon prepared by physical activation with carbon dioxide. The activation temperature was studied in the range of 400-800°C by keeping the activation temperature at 800°C for 120 min. It was found that the porous properties of activated carbon decreased with an increase in carbonization temperature. The activated carbons prepared at the highest activation temperature at 800°C and activation time of 120 min gave the activated carbon with the highest of BET surface area and pore volume of 938 m2/g and 0.4502 cm3/g, respectively

  11. Temperature-Correlated Changes in Phytoplankton Community Structure Are Restricted to Polar Waters.

    Science.gov (United States)

    Ward, Ben A

    2015-01-01

    Globally distributed observations of size-fractionated chlorophyll a and temperature were used to incorporate temperature dependence into an existing semi-empirical model of phytoplankton community size structure. The additional temperature-dependent term significantly increased the model's ability to both reproduce and predict observations of chlorophyll a size-fractionation at temperatures below 2°C. The most notable improvements were in the smallest (picoplankton) size-class, for which overall model fit was more than doubled, and predictive skill was increased by approximately 40%. The model was subsequently applied to generate global maps for three phytoplankton size classes, on the basis of satellite-derived estimates of surface chlorophyll a and sea surface temperature. Polar waters were associated with marked decline in the chlorophyll a biomass of the smallest cells, relative to lower latitude waters of equivalent total chlorophyll a. In the same regions a complementary increase was seen in the chlorophyll a biomass of larger size classes. These findings suggest that a warming and stratifying ocean will see a poleward expansion of the habitat range of the smallest phytoplankton, with the possible displacement of some larger groups that currently dominate. There was no evidence of a strong temperature dependence in tropical or sub-tropical regions, suggesting that future direct temperature effects on community structure at lower latitudes may be small.

  12. Evaporation and Ignition Characteristics of Water Emulsified Diesel under Conventional and Low Temperature Combustion Conditions

    Directory of Open Access Journals (Sweden)

    Zhaowen Wang

    2017-07-01

    Full Text Available The combination of emulsified diesel and low temperature combustion (LTC technology has great potential in reducing engine emissions. A visualization study on the spray and combustion characteristics of water emulsified diesel was conducted experimentally in a constant volume chamber under conventional and LTC conditions. The effects of ambient temperature on the evaporation, ignition and combustion characteristics of water emulsified diesel were studied under cold, evaporating and combustion conditions. Experimental results showed that the ambient temperature had little effect on the spray structures, in terms of the liquid core length, the spray shape and the spray area. However, higher ambient temperature slightly reduced the Sauter Mean Diameter (SMD of the spray droplets. The auto-ignition delay time increased significantly with the decrease of the ambient temperature. The ignition process always occurred at the entrainment region near the front periphery of the liquid core. This entrainment region was evolved from the early injected fuel droplets which were heated and mixed by the continuous entrainment until the local temperature and equivalence ratio reached the ignition condition. The maximum value of integrated natural flame luminosity (INFL reduced by 60% when the ambient temperature dropped from 1000 to 800 K, indicating a significant decrease of the soot emissions could be achieved by LTC combustion mode than the conventional diesel engines.

  13. Improving image quality by accounting for changes in water temperature during a photoacoustic tomography scan.

    Directory of Open Access Journals (Sweden)

    Dominique Van de Sompel

    Full Text Available The emerging field of photoacoustic tomography is rapidly evolving with many new system designs and reconstruction algorithms being published. Many systems use water as a coupling medium between the scanned object and the ultrasound transducers. Prior to a scan, the water is heated to body temperature to enable small animal imaging. During the scan, the water heating system of some systems is switched off to minimize the risk of bubble formation, which leads to a gradual decrease in water temperature and hence the speed of sound. In this work, we use a commercially available scanner that follows this procedure, and show that a failure to model intra-scan temperature decreases as small as 1.5°C leads to image artifacts that may be difficult to distinguish from true structures, particularly in complex scenes. We then improve image quality by continuously monitoring the water temperature during the scan and applying variable speed of sound corrections in the image reconstruction algorithm. While upgrading to an air bubble-free heating pump and keeping it running during the scan could also solve the changing temperature problem, we show that a software correction for the temperature changes provides a cost-effective alternative to a hardware upgrade. The efficacy of the software corrections was shown to be consistent across objects of widely varying appearances, namely physical phantoms, ex vivo tissue, and in vivo mouse imaging. To the best of our knowledge, this is the first study to demonstrate the efficacy of modeling temporal variations in the speed of sound during photoacoustic scans, as opposed to spatial variations as focused on by previous studies. Since air bubbles pose a common problem in ultrasonic and photoacoustic imaging systems, our results will be useful to future small animal imaging studies that use scanners with similarly limited heating units.

  14. Direct Microscale Measurement of Mouse Oocyte Membrane Permeability to Water and Ethylene Glycol at Subzero Temperatures Using Cryomicroscopy.

    Science.gov (United States)

    Han, X

      BACKGROUND: Investigation of cell osmotic behavior at subzero temperatures is of critical importance to the optimization of cooling procedures for cryopreservation. Based on established thermodynamic models, plasma membrane permeability coefficients for water and cryoprotectant agent (CPA) (Lcpa, Pp) and their activation energies (EaLp, EaPcpa) are essential to predict the change of cell volume and composition of intracellular solutions corresponding to different cooling procedures. However, currently available methods to measure Lp at subzero temperatures suffer from technical difficulties due to ice formation and there are no generalized methods to measure Pcpa at subzero temperatures. The present study aims to investigate cell osmotic behavior at subzero temperatures without ice formation. In the study cells were directly injected into super-cooled CPA solutions mounted on a cryomicroscope, and the corresponding osmotic properties were measured. Using ethylene glycol (EG), the value of PEG for mouse (CD-1) metaphase II oocytes at 0, -5, -10 degree C was determined to be 8.451.20, 7.430.91, 6.401.10, x10-6 cm/min, respectively, and EaPEG was calculated to be 3.9 kCal/mol. Lp in the presence of EG (LpEG) at 0, -5, -10 , -15 degree C was determined to be 7.0 1.15, 4.90 1.20, 2.44 0.31, 1.200.24, x 10-2 µm/min/atm, respectively, and EaLp was calculated to be 15.5 kCal/mol. Comparing these values with those previously measured at superzero temperatures, we concluded that for mouse oocytes, the Arrhenius relationship for LpEG is consistent at superzero and subzero temperatures, but the values of PEG at subzero temperatures are much lower than the extrapolated values from the Arrhenius relationship at superzero temperatures, possibly caused by membrane phase transition at low temperatures.

  15. LOW WATER TEMPERATURE AND ITS EFFECTS ON STRESS RESPONSE OF GREY MULLETS Mugil cephalus ACCLIMATED IN FRESHWATER

    Directory of Open Access Journals (Sweden)

    Vitas Atmadi Prakoso

    2015-06-01

    Full Text Available Grey mullet (Mugil cephalus can adapt to saline and freshwater. Although belonged to euryhaline species, but information regarding their stress response on low temperature. Environmental disturbance such as low water temperature may effect their physiological condition. These information can be useful for aquaculture development of this species in freshwater. Therefore, the purpose of study was to investigate the effects of low water temperature on the stress response of grey mullets Mugil cephalus acclimated in freshwater. The blood samples of experimental fish (TL: 28.2±1.1 cm, BW: 198.6±25.9 g were collected during winter season when the water temperature of controlled rearing system was stable at 25°C and uncontrolled rearing system slowly dropped until 12°C. Their stress response on both rearing systems was observed. The results showed that low temperature affected to lower the behavior activity and increase the stress response of grey mullets. The breath frequency of grey mullet regarding their opercular movement at 12°C was 74-97 breath/min., while at 25°C it was 95-114 breath/min. Hematocrit (Ht and hemoglobin (Hb were shown higher values of 43.5% and 9.5 g/dL, respectively at 25°C than 12°C (28.0% and 7.1 g/dL, respectively. The tendencies of cortisol and glucose level increased with the lowering temperature, showing higher value of 264.8 ng/mL and 35.5 mg/dL in 12°C than 5.5 ng/mL and 32.7 mg/dL in 25°C. The chemical properties of blood in grey mullets showed same tendency comparing between 12°C and 25°C, there was no significant different between each temperature, except for chloride (P<0.05. Chloride value was higher at 25°C, while other blood components such as osmolality, sodium, potassium, and magnesium were showing no significant differences. However, the results showed lower values at 12°C in every blood components, except for chloride. In conclusion, lowering water temperature to 12°C had impact

  16. The effect of cloud liquid water on temperature retrievals from microwave measurements

    Science.gov (United States)

    Bernet, Leonie; Navas-Guzmán, Francisco; Kämpfer, Niklaus

    2017-04-01

    Ground-based microwave radiometry provides atmospheric profiles for both clear sky and cloudy weather conditions. The effect of clouds on measurements from microwave radiometers is low compared to other remote sensing techniques but cannot be neglected at certain frequencies. In this study, clouds have been characterized and included in microwave retrievals in order to investigate their effect on tropospheric temperature profiles measured by the TEMPERA microwave radiometer. TEMPERA retrieves atmospheric temperature profiles by measuring emitted radiation of molecular oxygen at around 60 GHz. Because cloud liquid water also absorbs and emits radiation at the used frequency range, it is important to analyse the influence of liquid water on the microwave retrieval. In order to characterize the clouds, data from various instruments have been used, all located at the aerological station of MeteoSwiss at Payerne (Switzerland). Cloud base altitudes were detected using ceilometer measurements while the integrated liquid water (ILW) was measured by a HATPRO radiometer. Additional cloud information was obtained from a co-located sky camera and using an automatic partial cloud amount detection algorithm (APCADA). All this information has been used to characterize the clouds by means of a Liquid Water Content (LWC) profile. Different LWC profiles (shapes and values) have been tested to find the best cloud characterization depending on cloud type, altitude and ILW. Temperature profiles have been obtained incorporating this liquid water profile in the inversion algorithm and they have been evaluated against retrievals without considering clouds, in order to assess the liquid water effect on microwave measurements. The results have been compared with the temperature profiles from radiosondes which are regularly launched twice a day at the aerological station. Two years of data have been analyzed and almost 300 non-precipitating cloud cases were studied. The statistical analysis

  17. Analysis of the effect of water activity on ice formation using a new thermodynamic framework

    Science.gov (United States)

    Barahona, D.

    2014-07-01

    In this work a new thermodynamic framework is developed and used to investigate the effect of water activity on the formation of ice within supercooled droplets. The new framework is based on a novel concept where the interface is assumed to be made of liquid molecules "trapped" by the solid matrix. It also accounts for the change in the composition of the liquid phase upon nucleation. Using this framework, new expressions are developed for the critical ice germ size and the nucleation work with explicit dependencies on temperature and water activity. However unlike previous approaches, the new model does not depend on the interfacial tension between liquid and ice. The thermodynamic framework is introduced within classical nucleation theory to study the effect of water activity on the ice nucleation rate. Comparison against experimental results shows that the new approach is able to reproduce the observed effect of water activity on the nucleation rate and the freezing temperature. It allows for the first time a phenomenological derivation of the constant shift in water activity between melting and nucleation. The new framework offers a consistent thermodynamic view of ice nucleation, simple enough to be applied in atmospheric models of cloud formation.

  18. Microwave measurements of temperature profiles, integrated water vapour, and liquid water path at Thule Air Base, Greenland.

    Science.gov (United States)

    Pace, Giandomenico; Di Iorio, Tatiana; di Sarra, Alcide; Iaccarino, Antonio; Meloni, Daniela; Mevi, Gabriele; Muscari, Giovanni; Cacciani, Marco

    2017-04-01

    A RPG Humidity And Temperature PROfiler (HATPRO-G2 ) radiometer was installed at Thule Air Base (76.5° N, 68.8° W), Greenland, in June 2016 in the framework of the Study of the water VApour in the polar AtmosPhere (SVAAP) project. The Danish Meteorological Institute started measurements of atmospheric properties at Thule Air Base in early '90s. The Thule High Arctic Atmospheric Observatory (THAAO) has grown in size and observing capabilities during the last three decades through the international effort of United States (NCAR and University of Alaska Fairbanks) and Italian (ENEA, INGV, University of Roma and Firenze) institutions (http://www.thuleatmos-it.it). Within this context, the intensive field campaign of the SVAAP project was aimed at the investigation of the surface radiation budget and took place from 5 to 28 July, 2016. After the summer campaign the HATPRO has continued to operate in order to monitor the annual variability of the temperature profile and integrated water vapour as well as the presence and characteristics of liquid clouds in the Artic environment. The combined use of the HATPRO together with other automatic instruments, such as a new microwave spectrometer (the water Vapour Emission Spectrometer for Polar Atmosphere VESPA-22), upward- and downward-looking pyranometers and pyrgeometers, a zenith-looking pyrometer operating in the 9.6-11.5 µm spectral range, an all sky camera, and a meteorological station, allows to investigate the clouds' physical and optical properties, as well as their impact on the surface radiation budget. This study will present and discuss the first few months of HATPRO observations; the effectiveness of the statistical retrieval used to derive the physical parameters from the HATPRO brightness temperatures will also be investigated through the comparison of the temperature and humidity profiles, and integrated water vapour, with data from radiosondes launched during the summer campaign and in winter time.

  19. Effects of Water and Low-Medium Temperature on Limestone from Mt Etna basement

    Science.gov (United States)

    Castagna, Angela; Ougier-Simonin, Audrey; Benson, Philip; Browning, John; Fazio, Marco; Walker, Richard; Vinciguerra, Sergio

    2017-04-01

    Mount Etna volcano, Sicily, sits atop a structurally complex sedimentary basement continuously subjected to tectonic deformation. The flyschoid formations belonging to the Appenninic-Maghrebian Chain (AMC) and making up the accretionary wedge of a regional fold-and-thrust belt lie above carbonate Hyblean Plateau (HP) sequences, belonging to the African plate. Carbonate rocks represent a major component of the sedimentary basement: they are spread throughout the AMC as continuous strata and discontinuous lenses, and are the main constituent (e.g., Comiso Limestone) of the HP foreland. Etna is an active volcanic environment, characterized by complex stress field distributions, magmatic and non-magmatic fluid circulation, and elevated temperature gradients; the edifice has been constructed at various rates and with variable distribution of effusive products. These intrinsic and extrinsic parameters are known to impact the rheological behaviour of rocks. Previous triaxial deformation studies on carbonates (Tavel Limestone, Solnhofen Limestone and Comiso Limestone) have shown the importance of temperature, and the presence of water as pore fluid, on the mechanical strength and failure mode of the rocks. However, to our knowledge, no previous studies have considered the distal heating effect of intrusions on the carbonate mechanical strength from the basement. Here we investigate the behaviour under varying P-T conditions at constant strain rate (10-5 s-1) on both dry and water saturated samples of Comiso Limestone, a low-porosity (10.2% average) carbonate rock belonging to the HP. We ran separate conventional triaxial experiments at various confining effective pressure from 0 up to 50 MPa at room temperature (20°C), in both dry and drained water-saturated conditions, using natural samples, and thermally-treated samples (150°C, 300°C, and 450°C). Acoustic Emissions and P-wave velocities were recorded during the experiments. Sample failure covers the brittle and

  20. Thermal infrared remote sensing for riverscape analysis of water temperature heterogeneity: current research and future directions

    Science.gov (United States)

    Dugdale, S.; Hannah, D. M.; Malcolm, I.; Bergeron, N.; St-Hilaire, A.

    2016-12-01

    Climate change will increase summer water temperatures in northern latitude rivers. It is likely that this will have a negative impact on fish species such as salmonids, which are sensitive to elevated temperatures. Salmonids currently avoid heat stress by opportunistically using cool water zones that arise from the spatio-temporal mosaic of thermal habitats present within rivers. However, there is a general lack of information about the processes driving this thermal habitat heterogeneity or how these spatio-temporal patterns might vary under climate change. In this paper, we document how thermal infrared imaging has previously been used to better understand the processes driving river temperature patterns. We then identify key knowledge gaps that this technology can help to address in the future. First, we demonstrate how repeat thermal imagery has revealed the role of short-term hydrometeorological variability in influencing longitudinal river temperature patterns, showing that precipitation depth is strongly correlated with the degree of longitudinal temperature heterogeneity. Second, we document how thermal infrared imagery of a large watershed in Eastern Canada has shed new light on the landscape processes driving the spatial distribution of cool water patches, revealing that the distribution of cool patches is strongly linked to channel confinement, channel curvature and the proximity of dry tributary valleys. Finally, we detail gaps in current understanding of spatio-temporal patterns of river temperature heterogeneity. We explain how advances in unmanned aerial vehicle technology and deterministic temperature modelling will be combined to address these current limitations, shedding new light on the landscape processes driving geographical variability in patterns of river temperature heterogeneity. We then detail how such advances will help to identify rivers that will be resilient to future climatic warming, improving current and future strategies for

  1. WATER TEMPERATURE and other data from COOK from 1989-02-07 to 1989-12-14 (NODC Accession 9500116)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The water depth and temperature data was collected as part of Global Temperature- Salinity Pilot Project (GTSPP) from HMAS Cook by the Australian Oceanographic Data...

  2. Continuous Water Vapor Mass Flux and Temperature Measurements in a Model Scramjet Combustor Using a Diode Laser Sensor

    National Research Council Canada - National Science Library

    Upschulte, B. L; Miller, M. F; Allen, M. G; Jackson, K; Gruber, M; Mathur, T

    1998-01-01

    A sensor for simultaneous measurements of water vapor density, temperature and velocity has been developed based on absorption techniques using room temperature diode lasers (InGaAsP) operating at 1.31 micrometers...

  3. MODIS/Terra Near Real Time (NRT) Temperature and Water Vapor Profiles 5-Min L2 Swath 5km

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-2 MODIS Temperature and Water Vapor Profile Product MOD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature...

  4. MODIS/Aqua Near Real Time (NRT) Temperature and Water Vapor Profiles 5-Min L2 Swath 5km

    Data.gov (United States)

    National Aeronautics and Space Administration — The level-2 MODIS Temperature and Water Vapor Profile Product MYD07_L2 consists of 30 gridded parameters related to atmospheric stability, atmospheric temperature...

  5. The effect of pressure and temperature on aluminium hydrolysis: Implications to trace metal scavenging in natural waters

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    Removal of aluminium through precipitation/scavenging in natural waters was evaluated based on its hydrolysis at different temperatures and pressures. In general, pH for the occurrence of cation hydrolysis was lowered with hike in temperature which...

  6. Water content or water activity: what rules crispy behavior in bread crust?

    Science.gov (United States)

    van Nieuwenhuijzen, N H; Primo-Martín, C; Meinders, M B J; Tromp, R H; Hamer, R J; van Vliet, T

    2008-08-13

    A dry crust loses its crispness when water migrates into the crust. It is not clear if it is the amount of water absorbed or the water activity ( a w) that leads to a loss of crispness. The hysteresis effect observed when recording a water sorption isotherm allowed us to study the effects of a w and moisture content separately. All experiments were carried out on model bread crusts made from Soissons bread flour. The effect of water content and water activity on the glass transition of model bread crusts was studied in detail using two complimentary techniques: phase transition analysis (PTA) and nuclear magnetic resonance (NMR). The results were compared with sensory data and results from a puncture test, which provided data on acoustic emission and fracture mechanics during breaking of the crusts. The water content of the crust was found to be decisive for the transition point as measured by PTA and NMR. However, both water content and water activity had an effect on perceived crispness and number of force and sound peaks. From this may be concluded that the distribution of the water in the samples with a history of high water content is more inhomogeneous, which results in crispy and less crispy regions, thus making them overall more crispy than samples with the same water content but higher a w.

  7. Effects of elevated water temperature on physiological responses in adult freshwater mussels

    Science.gov (United States)

    Ganser, Alissa M.; Newton, Teresa J.; Haro, Roger J.

    2015-01-01

    Freshwater mussels (order Unionoida) face multiple environmental stressors, which pose serious conservation challenges to this diverse assemblage of aquatic invertebrates. Of these stressors, elevated water temperature from global climate change and other anthropogenic sources may be the most ubiquitous and could be placing many mussel populations dangerously close to their thermal maxima.

  8. The effect of temperature on the catalytic conversion of Kraft lignin using near-critical water

    DEFF Research Database (Denmark)

    Nguyen, Thi Dieu Huyen; Maschietti, Marco; Åmand, Lars-Erik

    2014-01-01

    The catalytic conversion of suspended LignoBoost Kraft lignin was performed in near-critical water using ZrO2/K2CO3 as the catalytic system and phenol as the co-solvent and char suppressing agent. The reaction temperature was varied from 290 to 370 C and its effect on the process was investigated...

  9. Comparing Temperature Effects on E. Coli, Salmonella, and Enterococcus Survival in Surface Waters

    Science.gov (United States)

    The objective of this study was to compare dependency of survival rates on temperature for indicator organisms E. coli and Enterococcus and the pathogen Salmonella in surface waters. A database of 86 survival datasets from peer-reviewed papers on inactivation of E. coli, Salmonel...

  10. Observed and simulated temperature dependence of the liquid water path of low clouds

    Energy Technology Data Exchange (ETDEWEB)

    Del Genio, A.D.; Wolf, A.B. [NASA Goddard Institute for Space Studies, New York, NY (United States)

    1996-04-01

    Data being acquired at the Atmospheric Radiation Measurement (ARM) Southern great Plains (SGP) Cloud and Radiation Testbed (CART) site can be used to examine the factors determining the temperature dependence of cloud optical thickness. We focus on cloud liquid water and physical thickness variations which can be derived from existing ARM measurements.

  11. Impacct of scalding duration and scalding water temperature on broiler processing wastewater loadings

    Science.gov (United States)

    The effects of scalding water temperature and immersion time on impact to poultry processing wastewater (PPW) loading were evaluated following the slaughter of commercially raised broilers. Based on previous research, the hypothesis was that immersion time would have a significant impact on PPW load...

  12. Water temperature affects life-cycle duration of tadpoles of Natal ...

    African Journals Online (AJOL)

    Direct and indirect effects of climate change on amphibians include range shifts and changes in community structure. The Natal cascade frog Hadromophryne natalensis has an altitudinal range of some 2 400 m in KwaZulu-Natal, and presents an opportunity to assess how increased water temperatures may impact on ...

  13. Building phenomenological models that relate proteolysis in pork muscles to temperature, water and salt content.

    Science.gov (United States)

    Harkouss, Rami; Safa, Hassan; Gatellier, Philippe; Lebert, André; Mirade, Pierre-Sylvain

    2014-05-15

    Throughout dry-cured ham production, salt and water content, pH and temperature are key factors affecting proteolysis, one of the main biochemical processes influencing sensory properties and final quality of the product. The aim of this study was to quantify the effect of these variables (except pH) on the time course of proteolysis in laboratory-prepared pork meat samples. Based on a Doehlert design, samples of five different types of pork muscle were prepared, salted, dried and placed at different temperatures, and sampled at different times for quantification of proteolysis. Statistical analysis of the experimental results showed that the proteolysis index (PI) was correlated positively with temperature and water content, but negatively with salt content. Applying response surface methodology and multiple linear regressions enabled us to build phenomenological models relating PI to water and salt content, and to temperature. These models could then be integrated into a 3D numerical ham model, coupling salt and water transfers to proteolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. 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...

  15. Short-term stream water temperature observations permit rapid assessment of potential climate change impacts

    Science.gov (United States)

    Peter Caldwell; Catalina Segura; Shelby Gull Laird; Ge Sun; Steven G. McNulty; Maria Sandercock; Johnny Boggs; James M. Vose

    2015-01-01

    Assessment of potential climate change impacts on stream water temperature (Ts) across large scales remains challenging for resource managers because energy exchange processes between the atmosphere and the stream environment are complex and uncertain, and few long-term datasets are available to evaluate changes over time. In this study, we...

  16. Simulation of emergence of winter wheat in response to soil temperature, water potential and planting depth

    Science.gov (United States)

    Seedling emergence is a critical stage in the establishment of dryland wheat. Soil temperature, soil water potential and planting depth are important factors influencing emergence. These factors have considerable spatio-temporal variation making it difficult to predict the timing and percentage of w...

  17. On the development of high temperature ammonia-water hybrid absorption-compression heat pumps

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

    2015-01-01

    Ammonia-water hybrid absorption-compression heat pumps (HACHP) are a promising technology for development of ecient high temperature industrial heat pumps. Using 28 bar components HACHPs up to 100 °C are commercially available. Components developed for 50 bar and 140 bar show that these pressure...

  18. Stream Water and Groundwater Interaction Revealed by Temperature Monitoring in Agricultural Areas

    Directory of Open Access Journals (Sweden)

    Youngyun Park

    2013-10-01

    Full Text Available Variations in stream water, streambed, adjacent stream sediment, and groundwater temperatures in the Haean basin, Korea were examined using time series analyses including auto-correlation, spectral density, and cross-correlation functions. The temperatures of the ambient air, stream water, streambed (depth = 10 cm, and adjacent stream sediment (depth = 10 cm showed distinctive diurnal variations with long-term seasonal cooling trends, while groundwater temperature showed only a seasonal decreasing trend with little diurnal variations. Auto-correlations and spectral densities of the stream water, streambed, and sediment temperatures also revealed strong daily cyclical behaviors, with longer periodic cycles varying from weekly to monthly. Amplitudes and lag times of the streambed thermal signals were also affected by the hydraulic conductivities of the sediments. Lower hydraulic conductivity indicates a more attenuated and slower thermal response for the streambed. The calculated vertical water flow velocities of the streambed revealed that the investigated stream locations were under losing or gaining conditions, depending on the location and time.

  19. Change in Water-Holding Capacity in Mushroom with Temperature Analyzed by Flory-Rehner Theory

    NARCIS (Netherlands)

    Paudel, Ekaraj; Boom, R.M.; Sman, van der R.G.M.

    2015-01-01

    The change in water-holding capacity of mushroom with the temperature was interpreted using the Flory-Rehner theory for swelling of polymeric networks, extended with the Debye-Hückel theory for electrolytic interactions. The validity of these theories has been verified with independent sorption

  20. The fountain effect of ice-like water across nanotubes at room temperature.

    Science.gov (United States)

    Zhao, Kuiwen; Wu, Huiying

    2017-11-01

    The well-known fountain effect of superfluid helium can directly convert heat to mechanical work by the transport of the superfluid across narrow channels under a temperature difference. But it is regarded as a unique feature of superfluids, only occurring below the temperature of 2.17 K. Here we report a peculiar fountain effect of ice-like water across nanotubes at room temperature. Based on molecular simulations, we observed fascinating ultrafast fountain flow across nanotubes from the cold side to the hot side under a small temperature difference, due to the near-dissipationless nature of ice-like ordered water inside the nanotubes. Water molecules exhibit collective behavior and spontaneously convert thermal energy from the surrounding into directed motion without dissipation. A surprising pressure difference of up to 256 bar is generated from a temperature difference of 23 K, almost reaching the thermodynamic limit. This finding is anticipated to provide a new protocol for power harvesting devices, heat engines and nanomotors.

  1. Effects of temperature on type approval testing of ballast water treatment systems.

    Science.gov (United States)

    Drillet, Guillaume; Schmoker, Claire; Trottet, Aurore; Mahjoub, Mohamed-Sofiane; Duchemin, Matthieu; Andersen, Martin

    2013-04-01

    To limit the risk associated with invasion of habitats by exogenous species, the International Convention for the Control and Management of the Ships' Ballast Water and Sediments was adopted in February 2004 and may soon enter into force. The International Maritime Organization (IMO) has produced guidelines to assess the efficacy and reliability of Ballast Water Treatment Systems (BWTS), but no guidance on how to take temperature into account during test cycles has been provided yet. Temperature is one of the main factors influencing the distribution and ecology of organisms along latitudes. Its increase results in higher grazing, growth, and reproduction rates of zooplankton. Under dark conditions, phytoplankton loss is also increased due to faster natural decay as well as enhanced top down control from zooplankton. Increased temperatures also improve the efficacy of chemical treatment, whereas the decay rates of disinfectants and their byproducts are potentially accelerated. The IMO guidelines for the type approval of BWTS should be amended to include recommendations on how to take temperature into account. Failing to ensure comparability and reliability between tests may pose a threat to the environment and may create problems for those attempting to apply BWTS. We propose to use a fixed Q10 value and a temperature of reference to adjust the retention time in ballast water tanks during testing. Copyright © 2013 SETAC.

  2. Effect of temperature on anaerobic treatment of black water in UASB-septic tank systems.

    Science.gov (United States)

    Luostarinen, Sari; Sanders, Wendy; Kujawa-Roeleveld, Katarzyna; Zeeman, Grietje

    2007-03-01

    The effect of northern European seasonal temperature changes and low temperature on the performance of upflow anaerobic sludge blanket (UASB)-septic tanks treating black water was studied. Three UASB-septic tanks were monitored with different operational parameters and at different temperatures. The results indicated the feasibility of the UASB-septic tank for (pre)treatment of black water at low temperatures with respect to removal of suspended solids and dissolved organic material. Inoculum sludge had little effect on COD(ss) removal, though in the start-up phase some poorly adapted inoculum disintegrated and washed out, thus requiring consideration when designing the process. Removal of COD(dis) was at first negative, but improved as the sludge adapted to low temperature. The UASB-septic tank alone did not comply with Finnish or Dutch treatment requirements and should therefore be considered mainly as a pre-treatment method. However, measuring the requirements as mgCOD l(-1) may not always be the best method, as the volume of the effluent discharged is also an important factor in the final amount of COD entering the receiving water bodies.

  3. Development and evaluation of the Soil and Water Temperature Model (SWTM) for rural catchments

    Science.gov (United States)

    Kwon, Yonghwan; Koo, Bhon K.

    2017-10-01

    A physically-based energy balance model, the Soil and Water Temperature Model (SWTM), is developed in an effort to improve the soil temperature estimation for Korean rural watersheds or catchments, which are characterized by heterogeneous land-cover types and rugged topography and have many paddy fields retaining surface water during the growing season. The developed model is applied to a small rural catchment in South Korea where soil temperature is measured for two months, July to August 2008, at eight monitoring sites including forest, paddy field, dry field, and natural vegetation area. The degree of agreement between the simulated and observed soil temperature is quite good for the soil surface (RMSE 1.11-3.16 °C, R2 0.80-0.88), except for forests. Although some estimation errors resulting from data deficiency and model structure are observed, SWTM reasonably well simulates the spatial and temporal distribution of soil temperature at the catchment scale by considering the effects of topography, vegetation cover, and hydrological characteristics, especially the existence of surface water. SWTM is well suited for rural watersheds or catchments and expected to contribute to enhancing our understanding of watershed biogeochemical processes and managing the watershed environment.

  4. Performance of alkaline activated slag at high temperatures

    Directory of Open Access Journals (Sweden)

    Mejía de Gutiérrez, R.

    2004-12-01

    Full Text Available This paper presents an investigation into the performance of alkali-activated slag (AAS mortar exposed to elevated temperatures. Sodium silicate, sodium hydroxide and a mix (waterglass with a modulus (SiO2/Na20 of 1.5 were used as activators. The specimens were heated in an electric furnace up to 1000 ºC in steps of 200 ºC for a constant period of 2 hours. The weight loss, residual compressive strength, resistance to chloride ion penetration, porosity and capillary sorption were evaluated and the results were compared with those of ordinary and blended Portland cement mortar

    En el presente traba jo se estudió el comportamiento frente a ¡a temperatura de morteros producidos a partir de escorias siderúrgicas activadas alcalinamente (EAA, utilizando diferentes activantes tales como silicato sódico, hidróxido de sodio y sus correspondientes mezclas. Cada espécimen se expuso por dos horas a temperaturas hasta de 1.000 ºC, en intervalos de 200 °C y en cada caso se determinaron los cambios de color peso, resistencia mecánica y durabilidad. Esta última propiedad se evaluó determinando las modificaciones de porosidad y permeabilidad a cloruros. Los resultados se comparan con los obtenidos en morteros de cemento Portland con y sin adición, específicamente con aquéllos que incorporan humo de sílice.

  5. Electrical resistivity dynamics beneath a fractured sedimentary bedrock riverbed in response to temperature and groundwater-surface water exchange

    Science.gov (United States)

    Steelman, Colby M.; Kennedy, Celia S.; Capes, Donovan C.; Parker, Beth L.

    2017-06-01

    Bedrock rivers occur where surface water flows along an exposed rock surface. Fractured sedimentary bedrock can exhibit variable groundwater residence times, anisotropic flow paths, and heterogeneity, along with diffusive exchange between fractures and rock matrix. These properties of the rock will affect thermal transients in the riverbed and groundwater-surface water exchange. In this study, surface electrical methods were used as a non-invasive technique to assess the scale and temporal variability of riverbed temperature and groundwater-surface water interaction beneath a sedimentary bedrock riverbed. Conditions were monitored at a semi-daily to semi-weekly interval over a full annual period that included a seasonal freeze-thaw cycle. Surface electromagnetic induction (EMI) and electrical resistivity tomography (ERT) methods captured conditions beneath the riverbed along a pool-riffle sequence of the Eramosa River in Canada. Geophysical datasets were accompanied by continuous measurements of aqueous specific conductance, temperature, and river stage. Time-lapse vertical temperature trolling within a lined borehole adjacent to the river revealed active groundwater flow zones along fracture networks within the upper 10 m of rock. EMI measurements collected during cooler high-flow and warmer low-flow periods identified a spatiotemporal riverbed response that was largely dependent upon riverbed morphology and seasonal groundwater temperature. Time-lapse ERT profiles across the pool and riffle sequence identified seasonal transients within the upper 2 and 3 m of rock, respectively, with spatial variations controlled by riverbed morphology (pool versus riffle) and dominant surficial rock properties (competent versus weathered rock rubble surface). While the pool and riffle both exhibited a dynamic resistivity through seasonal cooling and warming cycles, conditions beneath the pool were more variable, largely due to the formation of river ice during the winter season

  6. Activity of water in aqueous systems; A frequently neglected property

    OpenAIRE

    Blandamer, Mike J.; Engberts, Jan B. F. N.; Gleeson, Peter T.; Reis, João Carlos R.

    2005-01-01

    In this critical review, the significance of the term 'activity' is examined in the context of the properties of aqueous solutions. The dependence of the activity of water(l) at ambient pressure and 298.15 K on solute molality is examined for aqueous solutions containing neutral solutes, mixtures of neutral solutes and salts. Addition of a solute to water(l) always lowers its thermodynamic activity. For some solutes the stabilisation of water(l) is less than and for others more than in the ca...

  7. Evening physical activity alters wrist temperature circadian rhythmicity.

    Science.gov (United States)

    Rubio-Sastre, Patricia; Gómez-Abellán, Purificación; Martinez-Nicolas, Antonio; Ordovás, José María; Madrid, Juan Antonio; Garaulet, Marta

    2014-03-01

    The adequate time to perform physical activity (PA) to maintain optimal circadian system health has not been defined. We studied the influence of morning and evening PA on circadian rhythmicity in 16 women with wrist temperature (WT). Participants performed controlled PA (45 min continuous-running) during 7 days in the morning (MPA) and evening (EPA) and results were compared with a no-exercise-week (C). EPA was characterized by a lower amplitude (evening: 0.028 ± 0.01 °C versus control: 0.038 ± 0.016 °C; p evening: 0.41 ± 0.47 versus morning: 1.04 ± 0.59); and achrophase delay (evening: 06:35 ± 02:14 h versus morning: 04:51 ± 01:11 h; p evening might not be as beneficial as in the morning.

  8. Extraction temperature affects the activities of antioxidation, carbohydrate-digestion enzymes, and angiotensin-converting enzyme of Pleurotus citrinopileatus extract

    Directory of Open Access Journals (Sweden)

    Pao-Huei Chen

    2016-07-01

    Full Text Available Extraction temperature can potentially affect the chemical compositions and bioactivities of the extracts obtained. The objective of this study was to investigate the effect of extraction temperature on the distribution of bioactive compounds and the bioactivities of Pleurotus citrinopileatus. The antioxidant activities (2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid+ scavenging capabilities and the inhibitory capabilities on pancreatic α-amylase, intestinal α-glucosidase, and hypertension-linked angiotensin-converting enzyme of hot water P. citrinopileatus extract and cold water P. citrinopileatus extract were determined. The results showed that the antioxidant capabilities and inhibitory effects on α-amylase, α-glucosidase, and angiotensin-converting enzyme of cold water P. citrinopileatus extract were significantly higher than those of hot water P. citrinopileatus extract. The cold water P. citrinopileatus extracted was further precipitated with 100% ammonium sulfate to obtain a polysaccharide fraction or with 75% ethanol to obtain a protein fraction. The inhibitory activities of the protein fraction of the cold water P. citrinopileatus extract on α-amylase, α-glucosidase, and angiotensin-converting enzyme were significantly higher than those of the polysaccharide fraction. In conclusion, the protein fraction of the cold water P. citrinopileatus extract could be responsible for its bioactivities.

  9. Catchment controls on water temperature and the development of simple metrics to inform riparian zone management

    Science.gov (United States)

    Johnson, Matthew; Wilby, Robert

    2015-04-01

    Water temperature is a key water quality parameter and is critical to aquatic life Therefore, rising temperatures due to climate and environmental change will have major consequences for river biota. As such, it is important to understand the environmental controls of the thermal regime of rivers. The Loughborough University TEmperature Network (LUTEN) consists of a distributed network of 25 sites along 40 km of two rivers in the English Peak District, from their source to confluence. As a result, the network covers a range of hydrological, sedimentary, geomorphic and land-use conditions. At each site, air and water temperature have been recorded at a 15-minute resolution for over 4 years. Water temperature is spatially patchy and temporally variable in the monitored rivers. For example, the annual temperature range at Beresford Dale is over 18° C, whereas 8 km downstream it is less than 8° C. This heterogeneity leads to some sites being more vulnerable to future warming than others. The sensitivity of sites to climate was quantified by comparing the parameters of logistic regression models, constructed at each site, that relate water temperature to air temperature. These analyses, coupled with catchment modelling suggest that reaches that are surface-water dominated with minimal shade and relatively low water volumes are most susceptible to warming. Such reaches tended to occur at intermediate distances from rivers source in the monitored catchments. Reaches that were groundwater dominated had relatively stable thermal regimes, which were relatively unaffected by inter-annual changes in climatic conditions. Such areas could provide important thermal refuge to many organisms, which is supported by monitoring of the invertebrate community in the catchment. The phenology (i.e. timing of life events) of some species remained consistent between years in a river reach with a stable thermal regime, but changed markedly in other areas of the river. Consequently, areas

  10. Corrosion of High Chromium Ferritic/Martensitic Steels in High Temperature Water. a Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, P.; Lapena, J.; Blazquez, F. [Ciemat, Madrid (Spain)

    2000-07-01

    Available literature concerning corrosion of high-chromium ferritic/martensitic steels in high temperature water has been reviewed. The subjects considered are general corrosion, effect of irradiation on corrosion, stress corrosion cracking (SCC) and irradiation-assisted stress corrosion cracking (IASCC). In addition some investigations about radiation induced segregation (RIS) are shown in order to know the compositional changes at grain boundaries of these alloys and their influence on corrosion properties. The data on general corrosion indicate moderate corrosion rates in high temperature water up to 350 degree centigree. Considerably larger corrosion rates were observed under neutron irradiation. The works concerning to the behaviour of these alloys to stress corrosion cracking seem to conclude that in these materials is necessary to optimize the temper temperature and to carry out the post-weld heat treatments properly in order to avoid stress corrosion cracking. (Author) 40 refs.

  11. Characterization of hydrolytic degradation of polylactic acid/rice hulls composites in water at different temperatures

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available Hydrolytic degradations of polylactic acid/rice hulls (PLA/RH composites with various rice hulls contents due to water absorptions at 23, 51 and 69°C were investigated by studying the thermal properties, chemical composition, molecular weight, and morphology of the degraded products. The results have attested that the stability of PLA/RH composites in water depends slightly on rice hulls contents but it is significantly influenced by water temperature. Water absorption in 30 days at 23°C was between 0.87 and 9.25% depending on rice hull contents. However, at thermophilic temperatures, the water absorption and degradation of these products were increased significantly. Saturations were achieved in less than 25 and 9 days at 51°C and 69°C, respectively, while hydrolytic degradation was demonstrated by an increase in fragility and development of crystallinity. At 69°C, there were significant reductions of the decomposition and glass transition temperatures of the polymer by 13°C. These changes were associated with the reduction of the molecular weight of PLA from 153.1 kDa to ~10.7 kDa due to hydrolysis of its ester group.

  12. Temperature and water relations for sun and shade leaves of a desert broadleaf, Hyptis emoryi

    Energy Technology Data Exchange (ETDEWEB)

    Smith, W.K.; Nobel, P.S.

    1977-02-01

    The temperature and water relations of sun versus shade leaves of Hyptis emoryi Torr. were evaluated from field