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Other Temperatures (other + temperature)
Selected AbstractsPhysicochemical evaluation of silica-glass fiber reinforced polymers for prosthodontic applicationsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2005Gökçe Meriç This investigation was designed to formulate silica-glass fiber reinforced polymeric materials. Fused silica-glass fibers were chosen for the study. They were heat-treated at various temperatures (500°C, 800°C and 1100°C), silanized, sized and incorporated in two modified resin mixtures (A and B). The flexural properties in dry and wet conditions were tested and statistically analyzed, and the content of residual methyl methacrylate (MMA) monomer, dimensional changes with temperature, water sorption and solubility were determined. Woven fibers [36.9% (wt/wt)], heat-treated at 500°C, gave the highest strength values for the polymeric composites (an ultimate transverse strength of 200 Mpa and a flexural modulus of 10 GPa) compared with the fibers heat-treated at other temperatures. There was no statistically significant difference in the measured flexural properties between resins A and B regarding fiber treatment and water storage time. These fiber composites had a small quantity of residual MMA content [0.37 ± 0.007% (wt/wt)] and very low water solubility, indicating good biocompatibility. It was suggested that silica-glass fibers could be used for reinforcement as a result of their anticipated good qualities in aqueous environments, such as the oral environment. [source] Temperature and host species affect nuptial gift size in a seed-feeding beetleFUNCTIONAL ECOLOGY, Issue 6 2006C. W. FOX Summary 1In many insects species, males contribute large nutritional gifts to females during mating, generally as seminal fluids (ejaculates) or spermatophores. These nuptial gifts can affect both male and female fitness, and can mediate selection on male body size. However, it is unclear how environmental variables, such as temperature and diet, affect gift size and the consequences of gift size for male and female fitness. 2We examine how temperature and rearing host affect male nuptial gift size (both total ejaculate size and the proportion of a male's mass allocated to his seminal fluids), and the relationship between gift size and female reproduction, in two populations of the seed-feeding beetle Callosobruchus maculatus. 3Males reared at lower temperature (20 °C) produced substantially larger ejaculates than males reared at higher temperatures (25, 30 and 35 °C). However, males allocated a smaller proportion of their body mass to their ejaculate at the lowest temperature compared with other temperatures. This effect of temperature on male allocation to their ejaculates mirrored the effect of temperature on female body size , male ejaculate size remained a relatively constant proportion of their mate's body mass across temperatures. 4Rearing host also affected male ejaculate size but the magnitude and direction of the host effect differed between populations. 5Rearing temperature affected the relationship between male body mass and ejaculate size. Temperature also affected the relationship between female body mass and fecundity. The relationship between male body mass and ejaculate size was significantly lower when beetles were reared on cowpea than when beetles were reared on azuki or mung. 6We found no evidence that male body size or nuptial gift size affected female fecundity in either population of C. maculatus. We thus propose that the effect of nuptial gift size on male fitness is through a reduction in female mating frequency and thus increased paternity for males producing larger nuptial gifts. [source] Automatic characterization of ignition processes with machine learning clustering techniquesINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 10 2006Edward S. Blurock Machine learning clustering techniques are used to characterize and, after the training phase, to identify phases within an ignition process. For the ethanol mechanism used in this paper, four physically identifiable phases were found and characterized: the initiation phase, preignition phase, ignition phase, and the postignition phase. The clustering is done with respect to fuzzy logic predicates identifying the maxima, minima, and inflection points of the species profiles. The cluster descriptions characterize the phases found and are in human interpretable form. In addition, these descriptions are powerful enough to be used to predict the phase structure under new conditions. Cluster phases were calculated for the ethanol mechanism at an equivalence ratio of 0.5, a pressure of 3.3 bar, and the temperatures 1200, 1300, 1400, and 1500 K. The resulting cluster phase descriptions were then successfully used to predict the phase structure and ignition delay times for other temperatures in the range from 1200 to 1500 K. The effect of different fuzzy logic predicate profile descriptions is studied to emphasize that the boundaries of some phases, specifically that between the preignition and the ignition phase, are a matter of what the modeler considers important. The end of the ignition phase corresponds to the ignition delay time and was relatively independent of the predicate descriptions used to determine the phases. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 621,633, 2006 [source] EFFECT OF STORAGE TEMPERATURE ON THE GROWTH OF LISTERIA MONOCYTOGENES ON QUESO BLANCO SLICES,JOURNAL OF FOOD SAFETY, Issue 3 2006GAYLEN A. UHLICH ABSTRACT A five-strain cocktail of Listeria monocytogenes (104 cfu/mL) was inoculated onto individual vacuum-packaged slices (ca. 50 g each) of a commercial, Hispanic-style cheese, that being Queso Blanco. Growth was determined at appropriate intervals during storage at 5, 10, 15, 20 and 25C. In general, as the incubation temperature increased, a shorter lag phase duration (LPD) and a faster growth rate (GR) were observed. The LPD values at 5, 10, 15, 20 and 25C were 65.3, 19.9, 2.1, 8.4 and 11.4 h, respectively. The GR values were 0.011, 0.036, 0.061, 0.090 and 0.099 log cfu/h at 5, 10, 15, 20 and 25C, respectively. There were no statistical differences in LPD at 10, 15, 20 and 25C. However, the LPD during growth at 5C was statistically (P , 0.05) longer than at all other temperatures. The GR values at 20 and 25C were not significantly different from each other, whereas the GR values at 5, 10 and 15C were significantly different from each other as well as from the GR at 20 and 25C (P , 0.05). The maximum population density (MPD) showed relatively little variation over the range of storage temperatures tested, with an average of 8.38 log cfu/g (SD = 0.33). The results of this study indicate that not even the lowest trial temperature of 5C prevented growth over time of the inoculated L. monocytogenes on this sliced product, and that proper storage and handling procedures are required to prevent the bacterium from contaminating the product and/or to control its growth. [source] Zum Korrosionsverhalten von Nicrofer 3033 in hochkonzentrierter SchwefelsäureMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 12 2002H. Werner Untersuchungen zum Korrosionsverhalten von Nicrofer 3033 (1.4591) erfolgten in 93%iger und 95,99%iger technischer Schwefelsäure bei Temperaturen von 70,200°C. 6-h-Versuche mit gravimetrischer Auswertung und Messung des Freien Korrosionspotentials und 48-h-Versuche mit gravimetrischer Auswertung dienten zur Ermittlung des Einflusses von Schwefelsäurekonzentration und Temperatur bei An- und Abwesenheit von SO2 auf die Beständigkeit von Blechproben. Der Einfluss der Strömungsgeschwindigkeit wurde in 6-h-Versuchen durch Rotation von Rohrproben bei Umfangsgeschwindigkeiten bis 2 m/s untersucht. Aus den Potential- und gravimetrischen Messungen folgt für Temperaturen ab 100°C eine Beständigkeit mit , 0,1 mm/a für Nicrofer 3033 (1.4591) ab etwa 98,5%. Um 125°C scheint jedoch ein Gebiet zu existieren, wo zumindest bei längerer Versuchsdauer die Beständigkeit bis herab zu etwa 97,5% erhalten bleibt. Untersuchungen zum Strömungseinfluss weisen darauf hin, dass in dem genannten Gebiet mit zunehmender Strömungsgeschwindigkeit wieder eine Aktivierung erfolgt. Bei den anderen Temperaturen ist dagegen der Strömungseinfluss gering. Diese Ausweitung des Beständigkeitsbereiches um 125°C belegt, dass die Temperaturabhängigkeit von Nicrofer 3033 (1.4591) in hochkonzentrierter Schwefelsäure nicht monoton ist. Es treten in Abhängigkeit von der Schwefelsäurekonzentration bei unterschiedlichen Temperaturen Korrosionsmaxima und -minima auf. Bei Anwesenheit von SO2 erfolgt nur bei niedrigen Versuchstemperaturen, 80°C, 100°C im 6-h-Versuch und 70°C, 80°C im 48-h-Versuch, eine Einengung des Beständigkeitsbereiches. Contribution to corrosion behaviour of Alloy 33 in high concentrated sulfuric acid Investigations on the corrosive behaviour of Alloy 33 were conducted in 93% and 95,99% technical sulfuric acid at temperatures of 70,200°C. 6-h-tests with gravimetric evaluation and measurement of the free corrosion potential and 48-h-tests with gravimetric evaluation served to determine the influence of the sulfuric acid concentration and the temperature on the resistance of sheet samples at presence and absence of SO2. The influence of the flow rate was examined in 6-h-tests via rotation of pipe samples at circumferential speeds up to 2 m/s. The potential and gravimetric measurements showed that there is a resistance with , 0.1 mm/a for Alloy 33 as from about 98.5% at temperatures from 100°C. However, about 125°C there seems to be a zone at which the resistance down to about 97.5% is kept at least for a long test duration. Examinations on the flow influence indicate that there is a reactivation in the said zone with increasing flow speed. However, the flow influence is low at the other temperatures. This extension of the resistance zone about 125°C proves that the temperature sensitivity of Alloy 33 is not monotonous in highly concentrated sulfuric acid. There are corrosion maxima and minima as a function of the sulfuric acid concentration at different temperatures. If SO2 is present, there is only a limitation of the resistance zone at low test temperatures, 80°C, 100°C in the 6-h-test and 70°C, 80°C in the 48-h-test. [source] | ||||||||||