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Temperature Decreased (temperature + decreased)
Selected AbstractsGrowth and characterization of undoped, Sr2+ -, and Mn2+ -doped ammonium tetrachlorozincateCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2005M. A. Gaffar Abstract Crystals of ammonium tetrachlorozincate (AZC) undoped and doped with Sr2+ or Mn2+ in different concentrations were grown by the slow evaporation method from an aqueous solution. The crystal morphology changed considerably by doping. The dopant concentration in the crystals was measured by the atomic absorption technique. Slight changes in the unit cell parameters of AZC after doping with Sr2+ - or Mn2+ have been detected. Optical absorption measurements indicated strong influence of Sr2+ and Mn2+ doping. The optical energy gap at room temperature decreased continuously with increasing Sr2+ and Mn2+ concentration but with two different rates. The dc conductivity was also measured as a function of temperature for the undoped and two samples doped with 0.144 Sr2+ and 0.191 Mn2+ and the results were compared. Positions possibly occupied by Sr2+ and Mn2+ cations in AZC lattice have been identified. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Reproduction and metabolism at , 10°C of bacteria isolated from Siberian permafrostENVIRONMENTAL MICROBIOLOGY, Issue 4 2003Corien Bakermans Summary We report the isolation and properties of several species of bacteria from Siberian permafrost. Half of the isolates were spore-forming bacteria unable to grow or metabolize at subzero temperatures. Other Gram-positive isolates metabolized, but never exhibited any growth at , 10°C. One Gram-negative isolate metabolized and grew at , 10°C, with a measured doubling time of 39 days. Metabolic studies of several isolates suggested that as temperature decreased below + 4°C, the partitioning of energy changes with much more energy being used for cell maintenance as the temperature decreases. In addition, cells grown at , 10°C exhibited major morphological changes at the ultrastructural level. [source] Rapid Cooling Aborts Seizure-Like Activity in Rodent Hippocampal-Entorhinal SlicesEPILEPSIA, Issue 10 2000Matthew W. Hill Summary Purpose: As a preliminary step in the development of an implantable Peltier device to abort focal neocortical seizures in vivo, we have examined the effect of rapid cooling on seizures in rodent hippocampal-entorhinal slices. Methods: Seizure-like discharges were induced by exposing the slices to extracellular saline containing 4-aminopyridine (50 ,mol/L). Results: When we manually activated a Peltier device that was in direct contact with the slice, seizures terminated within seconds of the onset of cooling, sometimes preceding a detectable decrease in temperature measured near the top of the slice. However, activation of the Peltier device did not stop seizures when slices were no longer in direct physical contact with the device, indicating that this was not a field effect. When cooling was shut off and temperature returned to 33oC, bursting some-times returned, but a longer-term suppressive effect on seizure activity could be observed. In two of our experiments, a custom computer program automatically detected seizure discharges and triggered a transistor-transistor logic pulse to activate the Peltier device. In these experiments, the Peltier device automatically terminated the slice bursting in less than 4 seconds. When the Peltier device was placed in contact with the normal, exposed cortex of a newborn pig, we found that the cortical temperature decreased rapidly from 36oC to as low as 26oC at a depth of 1.7 mm below the cooling unit. Conclusions: These experiments show that local cooling may rapidly terminate focal paroxysmal discharges and might be adapted for clinical practice. [source] Factors influencing the fatty acid determination in fats and oils using Fourier transform near-infrared spectroscopyEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 9 2007Hormoz Azizian Abstract Fourier transform near-infrared (FT-NIR) technology is matrix dependent and thus highly dependent on factors that influence the absorption spectra. Ignoring these factors during the development of FT-NIR models will affect the accuracy and reliability of the classification of fats and oils and the determination of their fatty acid (FA) composition. Four factors were studied: the temperature at which samples are scanned, differences in FA chain length and number of double bonds, and the presence of non-triacylglycerol components. The results showed that an increase in the recording temperature decreased the absorption peak intensity, but not the position. FT-NIR spectral differences were linked to variations in molecular vibrations resulting from the number of carbon atoms or double bonds in the FA. The FT-NIR method could clearly differentiate between chain lengths from 10:0 to 18:0 and numbers of double bonds from zero (18:0) to three (18:3). Contaminants in triacylglycerols altered the FT-NIR spectra, resulting in increased errors in the FA content. An increased concentration of ,-sitosterol in triolein decreased or increased the observed contents of cis9-18:1 and cis11-18:1, respectively. An FT-NIR model adjusted for the phytosterol content corrected this discrepancy. The revised FT-NIR model was successfully used to provide the accurate FA compositions of commercial sunflower oils. [source] Horizontal and vertical movements of juvenile bluefin tuna (Thunnus orientalis) in relation to seasons and oceanographic conditions in the eastern Pacific OceanFISHERIES OCEANOGRAPHY, Issue 5 2007TAKASHI KITAGAWA Abstract Electronically tagged juvenile Pacific bluefin, Thunnus orientalis, were released off Baja California in the summer of 2002. Time-series data were analyzed for 18 fish that provided a record of 380 ± 120 days (mean ± SD) of ambient water and peritoneal cavity temperatures at 120 s intervals. Geolocations of tagged fish were estimated based on light-based longitude and sea surface temperature-based latitude algorithms. The horizontal and vertical movement patterns of Pacific bluefin were examined in relation to oceanographic conditions and the occurrence of feeding events inferred from thermal fluctuations in the peritoneal cavity. In summer, fish were located primarily in the Southern California Bight and over the continental shelf of Baja California, where juvenile Pacific bluefin use the top of the water column, undertaking occasional, brief forays to depths below the thermocline. In autumn, bluefin migrated north to the waters off the Central California coast when thermal fronts form as the result of weakened equatorward wind stress. An examination of ambient and peritoneal temperatures revealed that bluefin tuna fed during this period along the frontal boundaries. In mid-winter, the bluefin returned to the Southern California Bight possibly because of strong downwelling and depletion of prey species off the Central California waters. The elevation of the mean peritoneal cavity temperature above the mean ambient water temperature increased as ambient water temperature decreased. The ability of juvenile bluefin tuna to maintain a thermal excess of 10°C occurred at ambient temperatures of 11,14°C when the fish were off the Central California coast. This suggests that the bluefin maintain peritoneal temperature by increasing heat conservation and possibly by increasing internal heat production when in cooler waters. For all of the Pacific bluefin tuna, there was a significant correlation between their mean nighttime depth and the visible disk area of the moon. [source] Female zebra finches compromise clutch temperature in energetically demanding incubation conditionsFUNCTIONAL ECOLOGY, Issue 5 2010Andreas Nord Summary 1.,Avian embryos depend on the incubating parent to provide a thermal environment suitable for embryogenesis, but as the maintenance of optimal incubation temperatures is energetically costly, an incubating bird often must trade off embryonic investment against self-maintenance. 2.,We manipulated the energetic cost of incubation in female zebra finches (Taeniopygia guttata Vieillot) by varying ambient temperature and clutch size during nocturnal incubation and recorded the corresponding effects on incubation metabolic rate and clutch temperature. 3.,Females increased their night-time incubation metabolic rate more than twofold when incubating at 10 °C compared to when incubating close to thermoneutrality (28 °C). Furthermore, clutch enlargement caused females to elevate their metabolic rate with 2·8% per additional egg added to the clutch. 4.,However, despite spending more energy, females did not fully cover the increased costs of incubation, because clutch temperature decreased with decreasing ambient temperature and increasing clutch size. 5.,These findings suggest that parental investment in incubation can be energetically constrained and sometimes result in clutch temperatures below the optimal level for embryonic development, at least during nocturnal incubation. [source] Exergetic performance assessment of a pilot-scale heat pump belt conveyor dryerINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2010Zafer Erbay Abstract In this study, olive leaves were dried in a pilot-scale heat pump (HP) belt conveyor dryer as a thin layer. Drying experiments were carried out at the drying air temperature range of 45,55°C with the drying air velocity range of 0.5,1.5,m,s,1. The performance of the system and the process was evaluated using exergy analysis method. The exergy loss and flow diagram (the so-called Grassmann diagram) of the dryer system was presented to give quantitative information regarding the proportion of the exergy input that is dissipated in the various system components. Effects of the drying air temperature and the velocity on the performance of the drying process were discussed. The actual coefficient of performance values were obtained to be 2.37 for the HP unit and 2.31 for the overall system, respectively. The most important component of the system for improving the efficiency was determined to be the compressor. Exergetic efficiencies of the drying of olive leaves were in the range of 67.45,81.95%. It was obtained that they increased as the drying air temperature decreased and the drying air velocity increased. Copyright © 2009 John Wiley & Sons, Ltd. [source] Mathematical modelling of moisture sorption isotherms and determination of isosteric heat of blueberry variety O,NeilINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2009Antonio Vega-Gálvez Summary The sorption isotherms of blueberry variety O'Neil were determined at 20, 40 and 60 °C, for a range of water activity of 0.10,0.95. The isotherms showed that the equilibrium moisture content increased when temperature decreased at constant water activity. The BET, GAB, Halsey, Henderson, Caurie, Smith, Oswin and Iglesias-Chirife equations were tested for modelling the sorption isotherms. The results showed that GAB, BET and Halsey models gave the best fit quality for the experimental desorption data, and BET, Oswin and Henderson for adsorption data as suggested by the statistical tests employed. The net sorption heat was calculated using the Clausius,Clapeyron equation giving 38.62 kJ mol,1 (desorption) and 30.88 kJ mol,1 (adsorption) at a moisture content of 0.01 g water (g d.m.,1). Tsami equation was applied to estimate the net isosteric heat of sorption as function of equilibrium moisture content with satisfactory results. [source] Gelatinization kinetics of amaranth starchINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2001Andrea Calzetta Resio Summary The influence of the water:starch ratio and heating rate on the gelatinization of amaranth starch was investigated using differential scanning calorimetry. Onset and peak temperatures did not vary significantly with increase of water content, whereas the completion temperature decreased by more than 14 °C when the water content was in excess. A linear relationship was found between moisture content and gelatinization enthalpy for water:starch ratios between 0.81:1 and 2:1. From this relationship the minimum level of water necessary to initiate gelatinization was calculated. For water::starch ratios over 3:1, the enthalpy of gelatinization reached a maximum value. More rapid heating resulted in an increase of the peak and completion temperatures, as well as the gelatinization energy. Heating rates above 10 °C min,1 gave the maximum energy requirements for the completion of gelatinization in an excess of water. The kinetics of gelatinization of amaranth starch was analysed from the DSC traces. A simple mathematical model was tested to evaluate the kinetic parameters. It was shown that in an excess of water and for heating rates above 10 °C min,1, gelatinization followed first-order kinetics with n varying from 0.91 to 0.93. The activation energy was in the range of 157,185 kJ mol,1. However, the present analysis did not allow for the determination of the kinetic parameter values over the whole gelatinization range. [source] Mortality patterns in infectious salmon anaemia virus outbreaks in New Brunswick, CanadaJOURNAL OF FISH DISEASES, Issue 11 2005K L Hammell Abstract Mortality levels attributed to infectious salmon anaemia viral (ISAV) infections were examined at the net pen and site level in the 1996 smolt year class in three areas of New Brunswick, Canada. The year class in this region was the first known to have potential exposure to ISAV beginning at the time of seawater transfer. There was considerable variability in mortality patterns among net pen groups of fish. Net pen outbreak definitions were based on at least seven high mortality days in which there were at least 100 per 100 000 fish per day or >5% cumulative mortality for the study period. There were 106 net pen outbreaks in a study population consisting of 218 net pens. Although the number of new cases decreased as water temperature decreased, overall mortality levels at the study sites did not decrease noticeably. The median peak daily mortality rate during outbreaks was 492 per 100 000 fish per day, with 10% of cases experiencing >5200 mortalities per 100 000 fish per day. The median duration of outbreaks in net pens for which the fish were not slaughtered during the outbreak was 33 days and the median total loss in those outbreaks was 6600 per 100 000 fish. [source] EFFECTS OF EXTRUSION CONDITIONS ON PHYSICOCHEMICAL PROPERTIES OF A MUTANT RICE CULTIVAR, GOAMI2 , HIGH IN NONDIGESTIBLE CARBOHYDRATESJOURNAL OF FOOD QUALITY, Issue 5 2008I. CHOI ABSTRACT A mutant rice Goami2, a cultivar high in nondigestible carbohydrates (NDCs), was extrusion-cooked at feed moisture (20, 25%), screw speed (200, 300 rpm) and barrel temperature (110, 120 and 130C). Effects of extrusion conditions on the physical and functional properties were investigated. NDCs were determined by total dietary fiber (TDF) and resistant starch (RS) contents. Increasing moisture resulted in an increment of density, water absorption index (WAI) and hardness, and a decrement in expansion and water solubility index (WSI). A higher barrel temperature decreased the hardness and increased the WSI probably due to a higher proportion of gelatinized starch. Extrusion caused a reduction in TDF in the extrudates, as well as a significant decrease in RS contents. However, extrudates processed at moisture (%), screw speed (rpm) and barrel temperature (C) combinations of 25/200/110 and 25/200/120 showed no significant difference in TDF contents compared with its raw rice. Multiple regression models showed that feed moisture had the most pronounced effect on extrudate qualities, followed by barrel temperature and screw speed. PRACTICAL APPLICATIONS Rice, being one of the primary dietary sources of carbohydrates worldwide, is the major energy and nutritional sources. In recent years, demands have been increasing for rice with a wide range of value-added properties, such as enhanced nutrient, aroma, color and rice kernel shape, including functional properties. Goami2 is a mutant rice of Ilpumbyeo, a high japonica rice cultivar, and has been revealed to have higher nondigestible fractions. However, Goami2 rice has unsuitable properties for traditional cooking because of the difficulty of gelatinization, which might result in a hard texture of cooked rice compared with that of ordinary rice. On the basis of its nutritional and functional benefits, exploiting the possible utilization of Goami2 for processed food products would increase the potential consumption of Goami2 for various food products. [source] RHEOLOGICAL PROPERTIES OF SET YOGURT AS INFLUENCED BY INCUBATION TEMPERATURE AND HOMOGENIZATIONJOURNAL OF FOOD QUALITY, Issue 5 2002R.R. SHAKER The effect of incubation temperature and homogenization on the rheological nature of yogurt curd during gelation was investigated in this study. Our results indicated that the optimum incubation temperature for acid development was 45C. The minimum viscosity was observed at 40C while the maximum viscosity was at 48C. Our results also indicated that incubation temperature affected yogurt viscosity during the gelation process while homogenization had no significant effect. Increasing the incubation temperature decreased the flow behavior index and increased the consistency coefficient; homogenization increased the flow behavior index and decreased the consistency coefficient as described by a power law model. [source] Reduction of Acrylamide Formation in Potato Chips by Low-temperature Vacuum FryingJOURNAL OF FOOD SCIENCE, Issue 8 2004C. Granda ABSTRACT: Potatoes and other foods that have a high content of the amino acid asparagine and a high accumulation of reducing sugars are subject to the formation of acrylamide upon frying. The objectives of this research were (1) to analyze the level of acrylamide formed during deep-fat frying of potato chips and (2) to evaluate means of reducing acrylamide in potato chips by using different potato cultivars and vacuum frying. Several potato cultivars were used in this research, including Innovator (I), NDTX 4930,5W (N), ATX 854 04,8W (ATw), Atlantic (A), Shepody (S), ATX847806,2Ru (ATr), and White-Rose (W). An electric bench-top (atmospheric conditions)-type fryer was used to fry the potatoes. Three temperatures were used: 150 °C, 165 °C, and 180 °C. The vacuum frying experiments were performed at 118 °C, 125 °C, and 140 °C and a vacuum pressure of 10 Torr. The potatoes were sliced (1.5-mm thick) and fried for different lengths of times. For potatoes fried at 165 °C (for 4 min) at atmospheric conditions, the acrylamide contents were 5021 ± 55 ppb (W), 552 ± 25 ppb (I), 358 ± 50 ppb (N), 397 ± 25 ppb (ATw), 646 ± 55 ppb (A), 466 ± 15 ppb(S), and 537 ± 14 ppb (ATr). Vacuum frying reduced acrylamide formation by 94%. Results showed that both cultivar and modified frying systems can play an important role in reducing acrylamide formation in fried potatoes. As the frying temperature decreased from 180 °C to 165 °C, acrylamide content in potato chips reduced by 51% during traditional frying and by 63% as the temperature decreased from 140 °C to 125 °C in vacuum frying. Increased frying time increased acrylamide formation during traditional frying for all temperatures and frying methods analyzed. However, the effect on acrylamide concentration was greater for the traditional frying than the vacuum frying. Keywords: acrylamide, vacuum, frying, potato, temperature [source] Experimental and theoretical study of the influence of pressure on SCWOAICHE JOURNAL, Issue 11 2006M. D. Bermejo Abstract It is well known that pressure is an important parameter in the SCWO process, because it produces changes in the phase behavior and thermodynamics properties of the system. The influence of pressure on the oxidation efficiency of feeds containing isopropyl alcohol as fuel and acetic acid as waste was studied in an autothermal adiabatic transpiring wall reactor at pilot-plant scale, at pressures from 13 to 25 Mpa, and temperatures from 600 to 750°C. It was found that reaction temperature decreased between 40 and 100°C, when pressure was lowered, and, subsequently TOC removal decreased. At higher-temperatures, the decreasing of TOC removal due to pressure difference was reduced. The process was simulated at different pressures using a mathematical model previously developed for the reactor. The Anderko-Pitzer EoS, especially developed for aqueous systems at high-temperatures and pressures, was used to have accurate values of the heat capacities of the reaction mixture. It was found that having into account only the effect of pressure in the thermodynamical properties and in the concentration of the reagents, the experimental results could not be explained. Thus, the influence of the pressure in the reaction rate equation had to be considered. Results were qualitatively reproduced considering the reaction rate constant variable with pressure, using a constant volume of activation of ,1400 cm3/mol. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source] Measurement of the setting expansion of phosphate-bonded investment materials: Part I , Development of the Casting-Ring TestJOURNAL OF ORAL REHABILITATION, Issue 7 2004C. H. Lloyd summary, The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the ,Casting-Ring Test', the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14%, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation. [source] Dual responsive poly(N -isopropylacrylamide) hydrogels having spironaphthoxazines as pendant groupsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2009Erandimala U. Kulawardana Abstract Stimuli responsive hydrogels (PNIPAAm-MSp) with a thermoresponsive backbone and photochromic pendant groups were synthesized via free radical polymerization using N -isopropylacrylamide, modified spironaphthoxazines with a polymerizable double bond (MSp) as photochromic monomer, the crosslinker N,N,-methylenebis(acrylamide) and the initiator 2,2,-azobis(isobutyronitrile) in dimethylsulfoxide. The polymers are dual responsive, in that poly(N -isopropylacrylamide) (PNIPAAm) responds to temperature changes whereas the pendant spironaphthoxazines respond to light. Irradiation enhanced the water absorption of the polymers while increases in temperature decreased it. The irradiated PNIPAAm-MSp showed best water absorption at 0 °C (Q = 3.25) while water desorbed at higher temperatures (35 °C; Q = 0.30); where Q is the amount of water absorbed by a gram of dry polymer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3318,3325, 2009 [source] Effect of inoculum type and timing of application of Coniothyrium minitans on Sclerotinia sclerotiorum: influence on apothecial productionPLANT PATHOLOGY, Issue 5 2004E. E. Jones The effects of different inocula of the mycoparasite Coniothyrium minitans on carpogenic germination of sclerotia of Sclerotinia sclerotiorum at different times of year were assessed. A series of three glasshouse box bioassays was used to compare the effect of five spore-suspension inocula of C. minitans, including three different isolates (Conio, IVT1 and Contans), with a standard maizemeal,perlite inoculum. Apothecial production, as well as viability and C. minitans infection of S. sclerotiorum sclerotia buried in treated soil, were assessed. Maizemeal,perlite inoculum at 107 CFU per cm3 soil reduced sclerotial germination and apothecial production in all three box bioassays, decreasing sclerotial recovery and viability in the second bioassay and increasing C. minitans infection of sclerotia in the first bioassay. Spore-suspension inocula applied at a lower concentration (104 CFU per cm3 soil) were inconsistent in their effects on sclerotial germination in the three box bioassays. Temperature was an important factor influencing apothecial production. Sclerotial germination was delayed or inhibited when bioassays were made in the summer. High temperatures also inhibited infection of sclerotia by C. minitans. Coniothyrium minitans survived these high temperatures, however, and infected the sclerotia once the temperature decreased to a lower level. Inoculum level of C. minitans was an important factor in reducing apothecial production by sclerotia. The effects of temperature on both carpogenic germination of sclerotia and parasitism of sclerotia by C. minitans are discussed. [source] Effects of temperature and wetness duration on conidial infection, latent period and asexual sporulation of Pyrenopeziza brassicae on leaves of oilseed rapePLANT PATHOLOGY, Issue 4 2000T. Gilles Experiments in controlled environments were carried out to determine the effects of temperature and leaf wetness duration on infection of oilseed rape leaves by conidia of the light leaf spot pathogen, Pyrenopeziza brassicae. Visible spore pustules developed on leaves of cv. Bristol inoculated with P. brassicae conidia at temperatures from 4 to 20°C, but not at 24°C; spore pustules developed when the leaf wetness duration after inoculation was longer than or equal to approximately 6 h at 12,20°C, 10 h at 8°C, 16 h at 6°C or 24 h at 4°C. On leaves of cvs. Capricorn or Cobra, light leaf spot symptoms developed at 8 and 16°C when the leaf wetness duration after inoculation was greater than 3 or 24 h, respectively. The latent period (the time period from inoculation to first spore pustules) of P. brassicae on cv. Bristol was, on average, approximately 10 days at 16°C when leaf wetness duration was 24 h, and increased to approximately 12 days as temperature increased to 20°C and to 26 days as temperature decreased to 4°C. At 8°C, an increase in leaf wetness duration from 10 to 72 h decreased the latent period from approximately 25 to 16 days; at 6°C, an increase in leaf wetness duration from 16 to 72 h decreased the latent period from approximately 23 to 17 days. The numbers of conidia produced were greatest at 12,16°C, and decreased as temperature decreased to 8°C or increased to 20°C. At temperatures from 8 to 20°C, an increase in leaf wetness duration from 6 to 24 h increased the production of conidia. There were linear relationships between the number of conidia produced on a leaf and the proportion of the leaf area covered by ,lesions' (both log10 -transformed) at different temperatures. [source] The turning point on plots of log , and log t of Mo's equationPOLYMER INTERNATIONAL, Issue 7 2009Jian-bin Song Abstract BACKGROUND: Mo's equation based on the Avrami equation and Ozawa equation has been successfully used in non-isothermal crystallization kinetics by many researchers. However, in recent years we have found that plots of log ,,log t of Mo's equation are not straight lines, but there appears a turning point at , = 7 °C min,1 or so. The aim of this article is to analyze in detail the reason for the occurrence of this turning point by studying the non-isothermal crystallization of poly(vinylidene fluoride) (PVDF) using differential scanning calorimetry. RESULTS: A turning point at about 7 °C min,1 appeared on plots of log ,,log t. The cooling rate where the turning point occurred showed little change with increasing relative crystallinity, but the temperature decreased. It is noted that this turning-point temperature is lower than transition temperature of regime I , II reported for PVDF. CONCLUSION: We deemed that the occurrence of turning points on plots of log ,,log t of Mo's equation can be ascribed to the different crystallization regimes based on the Hoffman nucleation theory, and presumed that the turning point corresponded to transition of regime I , II. Finally, we considered that Mo's equation should be analyzed using two beelines, instead of one beeline. Copyright © 2009 Society of Chemical Industry [source] Impact of ultraviolet radiation on HDPE and HDPE/STC blendsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2009Min Qiao Abstract The structure and properties of high-density polyethylene (HDPE) ultraviolet irradiated in ozone atmosphere were studied by FTIR, XPS, GPC, XRD, DSC, TG, gel, and contact angle test. The oxygen-containing groups such as CO, CO, and C(O)O were quickly introduced onto HDPE chains through ultraviolet irradiation in ozone atmosphere; their content increased with increase in the time of ultraviolet irradiation. Compared with those of HDPE, the molecular weight of the irradiated HDPE decreased and its distribution became wider. There was no gel in the HDPE irradiated in ozone atmosphere. After ultraviolet irradiation for short times in ozone atmosphere, the water contact angle of the irradiated HDPE decreased and its hydrophilicity was improved. The crystal shape of the irradiated HDPE was still an orthorhombic structure; its cell parameter and the face space did not alter, but its melting temperature decreased slightly. Compared with that of HDPE, the temperature of initial weight loss for irradiated HDPE decreased. The irradiated HDPE/sericite-tridymite-cristobalite (STC) blends were prepared. The dispersion and compatibility of the irradiated HDPE/STC blends were improved compared with those of HDPE/STC blends; thus its mechanical properties increased. Copyright © 2008 John Wiley & Sons, Ltd. [source] High-Resolution Records of the Holocene Paleoenvironmental Variation Reflected by Carbonate and Its Isotopic Compositions in Bosten Lake and Response to Glacial ActivitiesACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 6 2009ZHANG Chengjun Abstract: The Early Holocene paleoclimate in Bosten Lake on the northern margin of the Tarim Basin, southern Xinjiang, is reconstructed through an analysis of a 953 cm long core (BSTC2000) taken from Bosten Lake. Multiple proxies of this core, including the mineral components of carbonate, carbonate content, stable isotopic compositions of carbonate, Ca/Sr, TOC and C/N and C/S of organic matter, are used to reconstruct the climatic change since 8500 a B.P. The chronology model is made by nine AMS 14C ages of leaves, seeds and organic matter contained in two parallel cores. The climate was cold and wet during 8500 to 8100 a B.P. Temperature increased from 8100 to 6400 a B.P., the climate was warm and humid, and the lake expanded. The lake level was highest during this stage. Then from 6400 to 5100 a B.P., the climate became cold and the lake level decreased slightly. During the late mid-Holocene, the climate was hot and dry from 5100 to 3100 a B.P., but there was a short cold period during 4400 to 3800 a B.P. At this temporal interval, a mass of ice and snow melting water supplied the lake at the early time and made the lake level rise. The second highest lake level stage occurred during 5200 to 3800 a B.P. The climate was cool and wet during 3100 to 2200 a B.P., when the lake expanded with decreasing evaporation. The lake had the last short-term high level during 3100 to 2800 a B.P. After this short high lake level period, the lake shrank because of the long-term lower temperature and reduced water supply. From 2200 to 1200 a B.P., the climate was hot and dry, and the lake shrank greatly. Although the temperature decreased somewhat from 1200 a B.P. to the present, the climate was warm and dry. The lake level began to rise a little again, but it did not reach the river bed altitude of the Konqi River, an outflow river of the Bosten Lake. [source] Temperature-Programmed Oxidation of Soot in a Hybrid Catalysis-Plasma SystemCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 1 2008H. Lin Abstract Non-thermal plasma (NTP) technology was applied to promote the temperature-programmed oxidation (TPO) of soot over a perovskites type of La0.8K0.2MnO3 catalyst. The O radicals originating from the decomposition of O2, as well as NO dissociation if nitrogen oxide were involved, reduce the ignition temperatures of soot. In NO-O2 -He, for example, the ignition temperature decreased to 240,°C from 290,°C as the voltage increased from 0,kV to 15,kV. The higher voltage also benefited the adsorption of NO molecules onto the catalyst surface (NOad). As a result, the maximum N2/NO ratio (conversion ratio of NO into N2) rose from 23,% to 53,%. Some of the NO molecules were dissociated into N and O radicals in plasma, and hence, the N2/NO ratio was further enhanced due to the combination of N atoms. In any case, the redox process between NOx and soot proved to be important in soot oxidation. [source] Persistent organic pollutants in air and vegetation from the canadian rocky mountainsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2004Deborah A. Davidson Abstract The exchange of chlorinated organic pollutants between air and vegetation in cold, mountain environments was investigated through the extraction of coniferous vegetation and high-volume air samples collected from the Canadian Rocky Mountains during the summers of 1999 and 2000. Concentrations of several compounds in vegetation increased as temperatures decreased, whereas atmospheric concentrations were not related to temperature. Daily cycling of these compounds between air and vegetation as a result of diurnal temperature changes was not observed. Compared with concentrations in vegetation from the Canadian Rocky Mountains, plant samples from the western valley in British Columbia (Canada) showed higher pollutant levels. Chemical partitioning between vegetation and air was not correlated with temperature, indicating that air contamination is governed by long-range transport and not by local revolatilization events. Based on these observations, we show that both deposition at higher altitudes and long-range atmospheric transport influence chemical accumulation in vegetation from the Canadian Rocky Mountains. [source] Thermoregulation and Heat Loss Prevention After Birth and During Neonatal Intensive-Care Unit Stabilization of Extremely Low-Birthweight InfantsJOURNAL OF OBSTETRIC, GYNECOLOGIC & NEONATAL NURSING, Issue 3 2007Robin Knobel Extremely low-birthweight infants have inefficient thermoregulation due to immaturity and may exhibit cold body temperatures after birth and during their first 12 hours of life. Hypothermia in these infants can lead to increased morbidity and mortality. Anecdotal notes made during our recent study revealed extremely low-birthweight infants' temperatures decreased with caregiver procedures such as umbilical line insertion, intubations, obtaining chest x-rays, manipulating intravenous lines, repositioning, suctioning, and taking vital signs during the first 12 hours of life. Therefore, nursing interventions should be undertaken to prevent heat loss during these caregiver procedures. Nurses can improve the thermal environment for extremely low-birthweight infants by prewarming the delivery room and placing the infant in a plastic bag up to the neck during delivery room stabilization to prevent heat loss. JOGNN, 36, 280-287 ; 2007. DOI: 10.1111/J.1552-6909.2007.00149.x [source] Effect of Chestnut Ink Disease on Photosynthetic PerformanceJOURNAL OF PHYTOPATHOLOGY, Issue 3 2004J. Gomes-Laranjo Abstract In order to evaluate the evolutionary impact of chestnut ink disease, infected trees (cv. Judia), were compared with non-infected trees, in three separate months: July, September and October. The aim of this work is to analyse the effects of the infection using parameters related to plant water relations, gas exchange and biometric data of leaves and fruits. In this period, temperatures decreased from 31 to 16°C contrarily to precipitation, which increased from 18 to 178 mm, respectively. In consequence, leaf water potential changed between ,1.6 and ,1.0 MPa while in infected plants the values maintained around ,1.2 MPa over the referred period. Nevertheless, at the gas exchanges level, differences in stomatal conductance, transpiration and photosynthesis were only detected in October. Concerning photosynthesis rate, the infected plants showed, in relation to September, a reduction around 35% whereas in non-infected plants the decline was 25%. Alterations in the chlorophyll contents were also observed between September and October. In infected plants reduction on total amount of chlorophyll was from 18.6 to 13.4 mg/Wf, while in non-infected plants values were only decayed from 15.1 to 13.1 mg/Wf. In relation to chlorophyll a/chlorophyll b ratio, plants infected by the oomycete preserved values in the level of 2.6, whereas in healthy plants values changed from 2.5 to 2.3. Leaves and fruits from infected chestnut trees were 13 and 20% smaller, respectively than those from non-infected. Fruits from infected plants also had less starch but more crude protein. [source] Synthesis, characterization, and in vitro degradation of thermotropic polyesters and copolyesters based on terephthalic acid, 3-(4-hydroxyphenyl)propionic acid, and glycolsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2001Minoru Nagata Abstract A new series of thermotropic liquid-crystalline (LC) polyesters were prepared from a diacyl chloride derivative of 4,4,-(terephthaloyldioxy)-di-4-phenylpropionic acid (PTP) and glycols with a different number of methylene groups (n) [HO(CH2)n OH, n = 6,10, 12] by high-temperature solution polycondensation in diphenyl oxide. PTP6/10 and PTP6/hydroquinone (H) LC copolyesters were also prepared according to a similar procedure. The chemical structure, LC, phase-transition behaviors, thermal stability, and solubility were characterized by elemental analysis, Fourier transform infrared spectroscopy, 1H and 13C NMR spectra, differential scanning calorimetry (DSC), thermogravimetric analysis, and a polarizing light microscope. The melting and isotropization temperatures decreased in a zigzag manner as the number of n increased. All of the polyesters formed a nematic phase with the exception of PTP8. The temperature ranges of the mesophase (,T) were much wider for the polyesters with an odd number of n's than those with an even number. ,T increased markedly for the PTP6/10 and PTP6/H copolyesters. The in vitro degradations of the polymers were ascertained by enzymatic hydrolysis and alkaline hydrolysis. The model compound, PTP dihexylester, was synthesized and found to be degraded into terephthalic acid, 3-(4-hydroxyphenyl)propionic acid, and 1-hexanol by Rhizopus delemar lipase, but PTPn homopolyesters and PTP6/10 and PTP6/H copolyesters were resistant to Rhizopus delemar hydrolysis. They were degradable in a sodium hydroxide buffer solution of pH 12 at 60 °C, depending on the number of n's and the copolymer composition. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3043,3051, 2001 [source] Effects of rare-earth oxide additions and heat-treatment temperature on the transformation and microstructure of silicon nitridePHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003Jinhui Dai Abstract In this paper, mixtures of Si3N4 powder with different added amounts of single rare-earth oxide Re2O3 (Re = Ce, Nd, Sm, Eu, Gd, Dy, Er, Yb) were heat treated at 1600,1800 °C and the effects of Re2O3 on the transformation and the microstructure of Si3N4 were investigated. Compared with the original Si3N4 powder, the transformation ratio of the Si3N4 powders obviously increased and the phase transformation finishing temperatures decreased by about 100 °C when different rare-earth oxides were added. When the heat-treatment temperature was 1700 °C, the transformation ratio of the Si3N4 powder was about 100%. When the heat-treatment temperature was 1600 °C and the amount of Re2O3 addition was 3 mol%, an anomalous transformation ratio occurred. In addition, it was found that the transformation ratio of Si3N4 changed periodically with the increase of the atomic number of the lanthanide when the heat-treatment temperature was 1650 °C or less. The SEM image of the Si3N4 powders obtained at 1700 °C indicated that the heavy lanthanide oxides such as Er2O3 and Yb2O3 were very helpful to develop rod-like ,-Si3N4 particles. [source] Climate and respiratory disease in Auckland, New ZealandAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 6 2009Ashmita Gosai Abstract Objective: Increases in the incidence of diseases are often observed during the cold winter months, particularly in cities in temperate climates. The study aim is to describe daily, monthly and seasonal trends in respiratory hospital admissions with climate in Auckland, New Zealand. Methods: Daily hospital admissions for total respiratory infections or inflammations (RII), total bronchitis and asthma (BA), and total whooping cough and acute bronchitis (TWCAB) for various age groups and ethnicities were obtained for the Auckland Region and compared with climate parameters on daily, monthly and seasonal time scales. Results: Seasonal and monthly relationships with minimum temperature were very strong (p<0.001) for RII over all age groups, for BA in the older age groups (14-64, 65+) and for TWCAB in the <1 year old age group. European, NZ M,ori and Pacific Islanders all showed increases in admissions as temperatures decreased. Pacific Islanders were particularly susceptible to RII. There was a lag in admissions of three to seven days after a temperature event. Conclusions and Implications: Results show that increases in respiratory admissions are strongly linked to minimum temperatures during winter, typical of cities with temperate climates and poorly-insulated houses. There are implications for hospital bed and staffing planning in Auckland hospitals. [source] | |||||||||||||||||||||||||