Home About us Contact
|
Home About us Contact | ||
|
|
||
Sample Temperature (sample + temperature)
Selected AbstractsTemperature Profiles in a Cylindrical Model Food During Pulsed Microwave HeatingJOURNAL OF FOOD SCIENCE, Issue 7 2001H.W. Yang ABSTRACT: Cylindrical 2%-agar gel samples were heated by pulsed and continuous microwave applications. The total microwave application time of 3 min was maintained for all experiments. Sample temperature was measured at various depths along the radial dimension to experimentally determine the internal temperature profile as a function of heating time. A local hot spot was observed at the center portion of the sample during the continuous microwave application. This hot spot was less significant during pulsed microwave applications, especially when longer intermittent power-off times were employed. An implicit finite-difference model was used to estimate temperature profiles within the sample during microwave heating. The estimated temperature profiles matched the experimental values well. [source] Thermal conductivity of wool and wool,hemp insulationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 1 2006Z. Ye Abstract Measurements have been obtained for the thermal resistance of sheep-wool insulation and wool,hemp mixtures, both in the form of bonded insulation batts, using a calibrated guarded hot-box. The density was 9.6,25.9 kg m,3 for the wool and 9.9,18.1 kg m,3 for the wool,hemp mixtures. The measurements were made at a mean sample temperature of 13.3°C using a calibrated guarded hot-box. The estimated uncertainly in the resistance measurements was of the order of ±7%. The thermal conductivity of the samples, derived from the thermal resistance measurements on the basis of the measured thickness, was well correlated with the density, although the variation with density was larger than that obtained in previous studies. The conductivity of the wool,hemp samples was not significantly different from that of the wool samples at the same density. Moisture uptake produced an increase of less than 5% in the conductivity of the bonded wool insulation for an increase in absorbed moisture content of 20%. The thermal resistance was 1.6% lower on average for samples oriented in the horizontal plane rather than the vertical plane, but this difference is not significant. Copyright © 2005 John Wiley & Sons, Ltd. [source] The effect of sample temperature on instrumental and sensory properties of mashed potato productsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2005Wenceslao Canet Summary The effect of sample temperature on texture, firmness and the sensory attributes of fresh and frozen/thawed natural and commercial mashed potatoes was studied. Scanning electron microscopy was used to obtain information on the structure of potato cells and how this is affected by processing. Various parameters were measured and were found to increase at 55 °C, these changes could be related to gelatinisation of the starch remaining in the products. In natural mashed potato, texture profile analysis (TPA) and firmness parameters were lower in the processed than in the fresh samples, indicating a weakening of the structure; this was confirmed by photomicrographs. In commercial mashed potato, TPA parameters measured at 55 and 65 °C and firmness parameters measured at 25 °C were higher in the processed samples, indicating enhanced structural strength; this was confirmed by photomicrographs. Firmness per gram of product was the best instrumental parameter for measuring texture in these products. The results of the different analyses indicated that 55 °C was the preferred temperature for consumption of mashed potatoes. [source] Nondestructive Measurement of Oxygen in Modified Atmosphere Packaged Hams Using a Phase-Fluorimetric Sensor SystemJOURNAL OF FOOD SCIENCE, Issue 8 2002D.B. Papkovsky ABSTRACT: The phase-fluorimetric oxygen sensing system recently developed by our team was used for nondestructive measurement of oxygen content in the heasdspace of 4 types of ham slice products. The system allowed accurate measurement of oxygen levels in all types of ham packs in a contact-less nondestructive fashion; it worked satisfactorily under ambient light and in conditions of direct contact with packaged cooked ham slices and variation of sample temperature. A primary screening for oxygen content of the modified atmosphere packs revealed that a significant proportion of packs contained elevated levels of oxygen. The sensor demonstrated minor changes in calibration as a result of direct physical contact with food and prolonged exposure. [source] Nanocoating hybrid polymer films on large quantities of cohesive nanoparticles by molecular layer depositionAICHE JOURNAL, Issue 4 2009Xinhua Liang Abstract The conformal coating of ultra-thin aluminum alkoxide (alucone) polymer films on primary silica and titania nanoparticles using molecular layer deposition (MLD) in a fluidized bed reactor from 100 to 160 °C is described. In situ mass spectrometry revealed that the growth of alucone MLD films was self-limiting as a function of the individual trimethylaluminum and ethylene glycol exposures. The composition and highly conformal alucone films throughout the surface of both silica and titania nanoparticles were confirmed. The highest growth rate was observed at the lowest sample temperature. Primary nanoparticles were coated individually despite their strong tendency to aggregate during fluidization. Based on the results of chemical and thermogravimetric analysis, the value of x in the formula of Al(OCH2CH2O)x was estimated to be 1.9. The calculated film density slightly increased from 2.0 ± 0.1 to 2.2 ± 0.1 g/cm3 with the increasing of temperature from 100 to 160 °C. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Raman scattering probe of anharmonic effects in NiSiJOURNAL OF RAMAN SPECTROSCOPY, Issue 7 2004S. K. Donthu Abstract We report a systematic temperature-dependent Raman scattering study of NiSi thin films. In agreement with the basic anharmonic theory, the strong Raman peak from NiSi at about 214 cm,1 shows phonon softening and broadening with an increase in the sample temperature. Comparative study of the temperature dependence of this first-order Raman peak from NiSi powder and the film show that NiSi layers of thickness 15,90 nm are under tensile thermal stress. The results also show that the total phonon shift observed in the temperature range 80,500 K is independent of the silicide film thickness. We have also shown that Raman spectroscopy is a faster and more sensitive technique than x-ray diffraction for phase identification in NiSi nanolayers, hence Raman scattering can be used as a valuable tool for in situ growth and process monitoring of nickel silicides. Copyright © 2004 John Wiley & Sons, Ltd. [source] Lattice parameter determination by coincidental multi-beam X-ray diffractionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009Mariana Borcha Abstract High-precision determination of the absolute value of lattice parameter for cubic single crystals is demonstrated by the example of silicon using coincidental multi-beam X-ray diffraction realized by superposition of two three-beam reflections at fixed sample temperature. Based on a semi-kinematical approximation of X-ray scattering theory, the algorithm for calculation of multi-beam diffractograms is developed enabling a more thorough quantitative analysis of experimental results. [source] Electrical insulation properties of sputter-deposited SiO2, Si3N4 and Al2O3 films at room temperature and 400 °CPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 3 2009Hagen Bartzsch Abstract In this paper the breakdown field strength and resistivity of sputter-deposited Al2O3, SiO2 and Si3N4 layers are investigated in the temperature range between room temperature and 400 °C. All the investigated layers showed excellent insulation properties, even at elevated sample temperature. One example of industrial application is the deposition of electrical insulation layers onto the membranes of pressure sensors using cluster type sputter equipment [source] Analysis of flavor and perfume using an internally cooled coated fiber deviceJOURNAL OF SEPARATION SCIENCE, JSS, Issue 7 2007Yong Chen Abstract A miniaturized internally cooled coated fiber device was applied for the analysis of flavors and fragrances from various matrices. Its integration with a CTC CombiPAL autosampler enabled high throughput for the analysis of analytes in complex matrices that required simultaneous heating of the matrices and cooling of the fiber coating to achieve high extraction efficiency. It was found that up to ten times increase of extraction efficiencies was observed when the device was used to extract flavor compounds in water, even when limited sample temperatures were used to preserve the integrity of target compounds. The extraction of the flavor compounds in water with the device was reproducible, with RSD not larger than 15%. The lower limits of the linear ranges were in the low ppb range, which was about one order of magnitude smaller than those obtained with the commercialized 100 ,m PDMS fibers. Exhaustive extraction of some perfume ingredients from a complex matrix (shampoo) was realized. All achieved recoveries were not less than 80%. The repeatability of the extraction of the perfume compounds from shampoo was better than 10%. The linear ranges were about 1,3000 ,g/g, and the LOD was about 0.2,1 ,g/g. The automated internally cooled coated fiber device was demonstrated to be a powerful sample preparation tool in flavor and fragrance analysis. [source] Soft X-ray radiation-damage studies in PMMA using a cryo-STXMJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2003Tobias Beetz Radiation damage sets a fundamental limit for studies with ionizing radiation; cryo-methods are known to ease these limits. Here, measurements on mass loss and the decrease in the C=O bond density as measured by oxygen-edge XANES (NEXAFS) spectroscopy in thin films of poly(methylmethacrylate) (PMMA), studied in a vacuum, are reported. While cryo-methods allow more than 95% of the mass to remain at doses up to ,Gy, there is little difference in C=O bond density versus dose between 298,K and 113,K sample temperatures. At both temperatures the critical dose for bond breaking is ,15 × 106,Gy. [source] Solar disinfection of poliovirus and Acanthamoeba polyphaga cysts in water , a laboratory study using simulated sunlightLETTERS IN APPLIED MICROBIOLOGY, Issue 2 2006W. Heaselgrave Abstract Aims:, To determine the efficacy of solar disinfection (SODIS) in disinfecting water contaminated with poliovirus and Acanthamoeba polyphaga cysts. Methods and Results:, Organisms were subjected to a simulated global solar irradiance of 850 Wm,2 in water temperatures between 25 and 55°C. SODIS at 25°C totally inactivated poliovirus after 6-h exposure (reduction of 4·4 log units). No SODIS-induced reduction in A. polyphaga cyst viability was observed for sample temperatures below 45°C. Total cyst inactivation was only observed after 6-h SODIS exposure at 50°C (3·6 log unit reduction) and after 4 h at 55°C (3·3 log unit reduction). Conclusions:, SODIS is an effective means of disinfecting water contaminated with poliovirus and A. polyphaga cysts, provided water temperatures of 50,55°C are attained in the latter case. Significance and Impact of the Study:, This research presents the first SODIS inactivation curve for poliovirus and provides further evidence that batch SODIS provides effective protection against waterborne protozoan cysts. [source] Convertibility of conductivity type in reactively sputtered ZnO thin filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003S. Tüzemen Abstract Possible negative- U behavior of the VO donor may explain rather unusual free carrier properties in as-sputtered ZnO thin films grown at extremely Zn-rich conditions. VO can act as a source of free electron concentration at sample temperatures above 210 K. Below this temperature it changes its charge state to an inactive neutral charge state where it cannot act as a donor because of a thermal barrier with a threshold temperature of 170,210 K. The thermal barrier for an electron to go to neutral charge state from positive charge state is approximately 162 meV. Material can be converted to p-type by annealing VO centers. O-rich growth conditions with low [VO] may result in p-type conductivity. [source] Magnetotransport in AlGaN/GaN and AlGaN/AlN/GaN heterostructuresPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2007G. A. Umana-Membreno Abstract Two-dimensional electron gas transport in AlN/GaN and AlGaN/GaN heterostructures has been investigated employing geometrical magnetoresistance measurements and quantitative mobility-spectrum analysis. The channel magnetoresistance of ungated four-terminal test structures, with an effective width to length ratio of 10, was measured using pulsed drain-to-source voltages equivalent to longitudinal electric fields up to 750 V/cm at magnetic field intensities up to 12 T and sample temperatures from 10 to 300 K. Two distinct electron populations, with significantly different mobilities, are shown to be present in the channel of both AlGaN/AlN/GaN and AlGaN/GaN heterostructures. It is also shown that application of longitudinal electric fields up to 750 V/cm cause a reduction in the mobility of these carrier populations and change the shape of mobility spectrum of the dominant electron population. The origin of these carrier populations is discussed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Interactions of trifluroethanol with the Trp-cage peptideBIOPOLYMERS, Issue 2-3 2007Chiradip Chatterjee Abstract It has been suggested that aggregation of fluorinated alcohols in water solutions is involved with the abilities of these alcohols to provoke conformational changes in peptides and proteins. The extent of fluoroalcohol aggregation depends on the degree of fluorination: hexafluoroisopropanol (HFIP) is more extensively aggregated than is TFE. We previously described a study of the interactions of HFIP with the peptide Trp-cage and provided evidence for the formation of long-lived complexes between this fluoroalcohol and the peptide. In the present work, we have examined the interactions of the less-fluorinated TFE with Trp-cage, in order to probe the role of fluoroalcohol aggregation in the phenomena observed. Intermolecular 1H{19F} nuclear Overhauser effects arising from interactions of TFE with the hydrogens of the peptide in a solution containing 42% TFE were determined at sample temperatures from 5 to 45°C. It is shown that the folded state of the peptide under these conditions is essentially the same as that observed in water and in 30% HFIP-water. The observed peptide,solvent NOEs indicate formation of complexes of Trp-cage with TFE that persist for times of the order of 1 ns. The interactions leading to complexes with TFE are somewhat weaker than those involved in complex formation with HFIP. There are no indications that the aggregation of fluoroalcohol is a necessary concomitant of the interactions of TFE or HFIP with Trp-cage. Rather, the stronger and more long-lived interactions of HFIP with Trp-cage appear to be primarily the result of the greater hydrogen-bonding ability and hydrophobicity of this fluoroalcohol. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 115,123, 2007. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] | |||||||||||||