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Experimental Temperature (experimental + temperature)
Kinds of Experimental Temperature Selected AbstractsFLOW PROPERTIES OF MALT CONCENTRATE-SWEETENED CONDENSED MILK MIXTURESJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2000S. TEJINDER ABSTRACT The rheological characteristics of various malt extract concentrate-sweetened condensed milk mixtures in the ratios of 50:50, 60:40, 70:30 and 80:20 (w/w) were studied at 30 to 80C, using a coaxial viscometer. The magnitudes of flow behavior index varied from 0.42,0.93. Experimental temperatures and concentrations of sweetened condensed milk considerably affected pseudoplasticity, consistency index and yield stress values of the mixtures. At 60 to 80C, the 60:40, 70:30 and 80:20 mixtures showed spectacularly higher flow behavior index values than those of the 50:50. The yield stress values increased with increasing temperature. The increases were considerably high in the 50:50 mixtures. The hulless barley malt concentrate-sweetened condensed milk mixtures, however, were mildly non-Newtonian and showed decreases in the values for yield stress with increasing temperatures. The activation energy values for flow behavior index and yield stress were negative in magnitudes, whereas those of consistency index were positive, which ranged from 1.6 to 15.0 Kcal/g mole. [source] Temperature and clinal variation in larval growth efficiency in Drosophila melanogasterJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2001S. J. W. Robinson Geographic clines in ectotherm species including Drosophila melanogaster have been found throughout the world, with genetically larger body size and shorter development time occurring at high latitudes. Temperature is thought to play a major role in the evolution of this clinal variation. Laboratory thermal selection has effects similar to those seen in geographical clines. Evolution at low temperatures results in more rapid development to larger adult flies. This study investigated the effects of geographical origin and experimental temperature on larval growth efficiency in D. melanogaster. Larvae from populations that had evolved at high latitudes were found to use limited food more efficiently, so that the overall adult body size achieved was larger. Larvae reared at a lower experimental temperature (18 °C) used food more efficiently than those reared at a higher temperature (25 °C). The increases in growth efficiency found in populations from high latitudes could explain their increased body size and more rapid development. [source] Increased body size confers greater fitness at lower experimental temperature in male Drosophila melanogasterJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2000Reeve Genetic variation of body size along latitudinal clines is found globally in Drosophila melanogaster, with larger individuals encountered at higher latitudes. Temperature has been implicated as a selective agent for these clines, because the body size of laboratory populations allowed to evolve in culture at lower temperatures is larger. In this study, we investigated the hypothesis that larger size is favoured at lower temperature through natural selection on adult males. We measured life-span and age-specific fertility of males from lines of flies artificially selected for body size at two different experimental temperatures. There was an interaction between experimental temperature and body size selection for male fitness; large-line males were fitter than controls at both temperatures, but the difference in fitness was greater at the lower experimental temperature. Smaller males did not perform significantly differently from control males at either experimental temperature. The results imply that thermal selection for larger adult males is at least in part responsible for the evolution of larger body size at lower temperatures in this species. The responsible mechanisms require further investigation. [source] Local Heating from Silver Nanoparticles and Its Effect on the Er3+ Upconversion in Oxyfluoride GlassesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2010Chao Liu The effect of silver (Ag) nanoparticles on the upconversion emission properties of Er3+ ions in oxyfluoride glasses was investigated, and a mechanism of the energy transfer proposed. The integrated intensity ratios between 522 and 545 nm emission bands of Er3+ ions in glasses containing Ag nanoparticles were strongly dependent on the size of the Ag nanoparticles as well as on the intensity of the 800 nm excitation laser. When the absorption of Ag nanoparticles overlapped with the 2H11/2 and 4S3/2 energy levels in Er3+ ions, a strong energy transfer occurred from Er3+: 2H11/2, 4S3/2 levels to Ag nanoparticles. This energy was then converted to a temperature rise in the vicinity of Er3+ ions, eventually leading to the large increase in the integrated intensity ratios. The estimated effective temperature was approximately 200 K higher than the experimental temperature when the excitation power was 700 mW. [source] Critical Factors Affecting the Wettability of ,-Alumina by Molten AluminumJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2004Ping Shen The wetting behaviors of ,-Al2O3 single crystals with three different faces,R(0112), A(01120), and C(0001),and polycrystals (PC) by molten aluminum were studied over a wide temperature range using both a conventional and an improved sessile-drop method. The critical factors affecting the wettability, such as temperature, atmosphere, substrate surface roughness, and crystallographic orientation, and the influence from the experimental technique, were thoroughly investigated. The results show that the aluminum surface oxidation and the thickness of the oxide film have a pronounced effect on the wettability, especially at low temperatures. To eliminate this effect, the experimental temperature must be over a critical value. Vacuum favors lowering this value compared with atmosphere, and the improved sessile-drop method, particularly using an impingement-dropping mode (I-mode), helps to weaken this effect by mechanical disruption and removal of the oxide film. However, the dropping distance and the dropping force must be controlled to prevent an overspreading of the drop. The effects of the substrate surface roughness and temperature are not significant in the case of a clean aluminum surface and a fine-prepared alumina surface. On the other hand, the effect of the alumina surface crystallographic orientation is noticeable and the wettability is in the order of R > A > PC > C. The intrinsic contact angles of the Al/,-Al2O3 system in the temperature range of 1000°,1500°C were estimated to be 76°,85° for the R and A faces, 88°,100° for the C face, and 77°,90° for the polycrystal, depending on the temperature. [source] Relationship among drug delivery behavior, degradation behavior and morphology of copolylactones derived from glycolide, l -lactide and ,-caprolactonePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 2 2002Qing Cai Abstract A series of copolylactones was synthesized by ring-opening copolymerization of glycolide, L -lactide and ,-caprolactone, using stannous octoate as catalyst. The in vitro degradation behaviors of them were studied and data demonstrated different degradation rates which mainly depended on the compositions. Investigation of the 5-fluorouracil (5-Fu) release from these copolylactones revealed that the composition, degradation rate and the morphology of the polymeric matrix played an important role on the drug release kinetics. A sustained 5-Fu release without initial time lag was obtained from random poly(lactide-co-glycolide-co-caprolactone) (r-PGLC) drug carrier, and it differed from the cases of polylactide (PLA) or random poly(lactide-co-glycolide) (PLGA), which usually showed an initial time lag or biphasic drug release behavior. It was due to the low glass transition temperature (Tg) of the r-PGLC and the drug would diffuse faster in rubbery state under the experimental temperature. Furthermore, a significant change in the drug release behavior of r-PGLC was observed when the temperatures were changed around the Tg of the drug carrier, which implied that the drug release behavior could be regulated by adjusting the morphology of the drug carrier. Copyright © 2002 John Wiley & Sons, Ltd. [source] Entropy,enthalpy compensation: Fact or artifact?PROTEIN SCIENCE, Issue 3 2001Kim Sharp Abstract The phenomenon of entropy,enthalpy (S-H) compensation is widely invoked as an explanatory principle in thermodynamic analyses of proteins, ligands, and nucleic acids. It has been suggested that this compensation is an intrinsic property of either complex, fluctuating, or aqueous systems. The questions examined here are whether the observed compensation is extra-thermodynamic (i.e., reflects anything more than the well-known laws of statistical thermodynamics) and if so, what does it reveal about the system? Compensation is rather variably defined in the literature and different usages are discussed. The most precise and interesting one, which is considered here, is a linear relationship between ,H and ,S for some series of perturbations or changes in experimental variable. Some recent thermodynamic data on proteins purporting to show compensation is analyzed and shown to be better explained by other causes. A general statistical mechanical model of a complex system is analyzed to explore whether and under what conditions extra-thermodynamic compensation can occur and what it reveals about the system. This model shows that the most likely behavior to be seen is linear S-H compensation over a rather limited range of perturbations with a compensation temperature Tc = d,H/d,S within 20% of the experimental temperature. This behavior is insensitive to the details of the model, thus revealing little extra-thermodynamic or causal information about the system. In addition, it will likely be difficult to distinguish this from more trivial forms of compensation in real experimental systems. [source] Physiological variation along a geographical gradient: is growth rate correlated with routine metabolic rate in Rana temporaria tadpoles?BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009BEATRICE LINDGREN Shorter season length and lower temperature towards higher latitudes and altitudes often select for intraspecific clines in development and growth rates. However, the physiological mechanisms enabling these clines are not well understood. We studied the relationship between routine metabolic rate (RMR) and larval life-history traits along a 1500-km latitudinal gradient across Sweden. In a laboratory common garden experiment, we exposed eight common frog Rana temporaria populations to two experimental temperatures (15 and 18 °C) and measured RMR using flow-through respirometry. We found significant differences among populations in RMR, but there was no evidence for a linear relationship between latitude and RMR in either temperature treatment. However, we found a concave relationship between latitude and RMR at the lower experimental temperature. RMR was not correlated with growth rate at population or at individual levels. The results obtained suggest that, unlike in growth and development rates, there is no latitudinal cline in RMR in R. temporaria tadpoles. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 217,224. [source] Increased body size confers greater fitness at lower experimental temperature in male Drosophila melanogasterJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2000Reeve Genetic variation of body size along latitudinal clines is found globally in Drosophila melanogaster, with larger individuals encountered at higher latitudes. Temperature has been implicated as a selective agent for these clines, because the body size of laboratory populations allowed to evolve in culture at lower temperatures is larger. In this study, we investigated the hypothesis that larger size is favoured at lower temperature through natural selection on adult males. We measured life-span and age-specific fertility of males from lines of flies artificially selected for body size at two different experimental temperatures. There was an interaction between experimental temperature and body size selection for male fitness; large-line males were fitter than controls at both temperatures, but the difference in fitness was greater at the lower experimental temperature. Smaller males did not perform significantly differently from control males at either experimental temperature. The results imply that thermal selection for larger adult males is at least in part responsible for the evolution of larger body size at lower temperatures in this species. The responsible mechanisms require further investigation. [source] A new formulation of garnet,clinopyroxene geothermometer based on accumulation and statistical analysis of a large experimental data setJOURNAL OF METAMORPHIC GEOLOGY, Issue 7 2009D. NAKAMURAArticle first published online: 13 JUL 200 Abstract Published experimental data including garnet and clinopyroxene as run products were used to develop a new formulation of the garnet,clinopyroxene geothermometer based on 333 garnet,clinopyroxene pairs. Only experiments with graphite capsules were selected because of difficulty in estimating the Fe3+ content of clinopyroxene. For the calibration, a published subregular-solution model was adopted to express the non-ideality of garnet. The magnitude of the Fe,Mg excess interaction parameter for clinopyroxene (WFeMgCpx), and differences in enthalpy and entropy of the Fe,Mg exchange reaction were regressed from the accumulated experimental data set. As a result, a markedly negative value was obtained for the Fe,Mg excess interaction parameter of clinopyroxene (WFeMgCpx = , 3843 J mol,1). The pressure correction is simply treated as linear, and the difference in volume of the Fe,Mg exchange reaction was calculated from a published thermodynamic data set and fixed to be ,120.72 (J kbar,1 mol,1). The regressed and obtained thermometer formulation is as follows: where T = temperature, P = pressure (kbar), A = 0.5 Xgrs (Xprp , Xalm , Xsps), B = 0.5 Xgrs (Xprp , Xalm + Xsps), C = 0.5 (Xgrs + Xsps) (Xprp , Xalm), Xprp = Mg/(Fe2+ + Mn + Mg + Ca)Grt, Xalm = Fe/(Fe2+ + Mn + Mg + Ca)Grt, Xsps = Mn/(Fe2+ + Mn + Mg + Ca)Grt, Xgrs = Ca/(Fe2+ + Mn + Mg + Ca)Grt, XMgCpx = Mg/(Al + Fetotal + Mg)Cpx, XFeCpx = Fe2+/(Al + Fetotal + Mg)Cpx, KD = (Fe2+/Mg)Grt/(Fe2+/Mg)Cpx, Grt = garnet, Cpx = clinopyroxene. A test of this new formulation to the accumulated data gave results that are concordant with the experimental temperatures over the whole range of the experimental temperatures (800,1820 °C), with a standard deviation (1 sigma) of 74 °C. Previous formulations of the thermometer are inconsistent with the accumulated data set; they underestimate temperatures by about 100 °C at >1300 °C and overestimate by 100,200 °C at <1300 °C. In addition, they tend to overestimate temperatures for high-Ca garnet (Xgrs , 0.30,0.50). This new formulation has been tested against previous formulations of the thermometer by application to natural eclogites. This gave temperatures some 20,100 °C lower than previous formulations. [source] Interpreting 2hJ(F,N), 1hJ(H,N) and 1J(F,H) in the hydrogen-bonded FH,collidine complex,MAGNETIC RESONANCE IN CHEMISTRY, Issue 12 2002Janet E. Del Bene Abstract Ab initio EOM-CCSD calculations were performed to determine 19F,1H, 19F,15N and 1H,15N spin,spin coupling constants in model complexes FH,NH3 and FH,pyridine as a function of the F,H and F,N distances. The absolute value of 1J(F,H) decreases and that of 1hJ(H,N) increases rapidly along the proton-transfer coordinate, even in the region of the proton-shared F,H,N hydrogen bond. In contrast, 2hJ(F,N) remains essentially constant in this region. These results are consistent with the recently reported experimental NMR spectra of FH,collidine which show that 1hJ(H,N) increases and 1J(F,H) decreases, while 2hJ(F,N) remains constant as the temperature of the solution decreases. They suggest that the FH,collidine complex is stabilized by a proton-shared hydrogen bond over the range of experimental temperatures investigated, being on the traditional side of quasi-symmetric at high temperatures, and on the ion-pair side at low temperatures. Copyright © 2002 John Wiley & Sons, Ltd. [source] Physiological variation along a geographical gradient: is growth rate correlated with routine metabolic rate in Rana temporaria tadpoles?BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009BEATRICE LINDGREN Shorter season length and lower temperature towards higher latitudes and altitudes often select for intraspecific clines in development and growth rates. However, the physiological mechanisms enabling these clines are not well understood. We studied the relationship between routine metabolic rate (RMR) and larval life-history traits along a 1500-km latitudinal gradient across Sweden. In a laboratory common garden experiment, we exposed eight common frog Rana temporaria populations to two experimental temperatures (15 and 18 °C) and measured RMR using flow-through respirometry. We found significant differences among populations in RMR, but there was no evidence for a linear relationship between latitude and RMR in either temperature treatment. However, we found a concave relationship between latitude and RMR at the lower experimental temperature. RMR was not correlated with growth rate at population or at individual levels. The results obtained suggest that, unlike in growth and development rates, there is no latitudinal cline in RMR in R. temporaria tadpoles. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 217,224. [source] | ||||||||||||||||