Quality of Infrared Dried Apple Slices

The aim of this work was to compare quality of apple slices dried by near infrared heating and convection in such parameters in which final material temperature in both methods was similar. The infrared drying was done at the distance between the emitters (with total power of 7.875 kW/m²) and heated surface equal to 10, 20, and 30 cm. Flow of ambient air was set at 0.5, 1.0, and 1.5 m/s. Convective drying was done in the same dryer using hot air at 65 and 75°C flowing with velocity 1.5 m/s. Quality attributes measured in this work included: color, kinetics of water adsorption, mechanical properties, and microstructure. It was stated that the changes in chromaticity coefficients are not dependent on the mode of heat supply, but are related to the final temperature of the dried material. Luminance of dried apple slices was affected by temperature as well. Final material temperature, not the way heat is supplied, could be responsible for the differences in the ability of dry apple slices to adsorb water. The similar correlation was stated for mechanical properties: slope of initial part of the deformation curve (crispness), breaking force (hardness or crispness), and work of breaking were all related to the final material temperature. Microstructure of convective and infrared dried apple were different but it seems that the drying rate can be responsible for observed differences.     

New global insight in ultrathin oxide reliability using accurateexperimental methodology and comprehensive database

In this paper, we critically examine several important experimental aspects concerning ultrathin oxide reliability. The statistical nature of breakdown measurements and the impact on data interpretation is discussed. Thickness dependence of Weibull slopes and its impact on reliability projection is reviewed. We also investigate the voltage-dependent voltage acceleration using two independent experimental methods over a wide range of oxide thickness values. Within the framework of a general defect generation model, we explore the possibility of a voltage-dependent defect generation rate to account for the increase in voltage acceleration with decreasing voltages. Using direct experimental results, we clarify that strong temperature dependence found on ultrathin oxides is a voltage effect, not a thickness effect as previously suggested, In the context of voltage-dependent voltage acceleration, we experimentally resolve various seemingly contradicting and confusing observations such as temperature-independent voltage acceleration and non-Arrhenius temperature dependence found on ultrathin oxides. Finally, we provide a global picture for time-to-breakdown in voltage and temperature domain constructed from two important empirical principles based on comprehensive experimental database     

Mesoporous niobosilicates serving as catalysts for synthesis of fragrances

Niobium-containing siliceous-MSU-X mesoporous molecular sieves have been prepared according to an original pathway by the reaction between low-cost niobium species (ammonium trisoxalate complex of niobium (V)), silica precursor (tetraethyl orthosilicate), and biodegradable surfactant in strong acidic, acidic or almost neutral medium. The selective oxidation of several terpenes and terpenoids (geraniol, limonene, α-terpineol) using hydrogen peroxide as an oxidant agent over novel Nb-catalysts is studied in this work. A variety of (Nb)MSU-X and (Ru,Nb)MSU-X materials prepared under different conditions has been employed (supermicroporous/mesoporous molecular sieves) for this purpose. The structure–function relationships in these catalysts are reported.     

RTD (residence time distribution) predictions in large mechanically aerated lagoons.

Mechanically aerated lagoons (used for wastewater treatment in the pulp and paper industry) are typically very large (>500,000 m3) and have complex three-dimensional fluid flow patterns due to mechanical agitation, sludge accumulation, internal baffling, and confined inlet/outlet flow channels. RTD data is frequently used for evaluation of hydraulic performance, however, obtaining accurate data with traditional dye measurements is a difficult and time-consuming process. Moreover, the mixing impact of factors such as aerator positions, sludge accumulation, and internal baffles would require a significant and costly number of local field measurements. Recent applications of CFD to mechanically aerated lagoons have helped engineers to understand the complex flow interactions. This paper provides a practical method for the evaluation of the hydraulic performance of large mechanically aerated lagoons using CFD. A method, based on random-walk Lagrangian particle tracking, has been developed to significantly shorten the computational time needed to produce RTD curves for these lagoons. Comparison of the particle method with the more conventional scalar transport yields excellent results. These methods allow wastewater engineers to combine their existing knowledge and expertise with the established power of CFD. The results quantify the hydraulic impact of different inlet/outlet configurations, aerator configurations, influent flow rates, and bottom sludge profiles.     

A 15O-H2O PET study of meditation and the resting state of normal consciousness

The aim of the present study was to examine whether the neural structures subserving meditation can be reproducibly measured, and, if so, whether they are different from those supporting the resting state of normal consciousness. Cerebral blood flow distribution was investigated with the 15O-H20 PET technique in nine young adults, who were highly experienced yoga teachers, during the relaxation meditation (Yoga Nidra), and during the resting state of normal consciousness. In addition, global CBF was measured in two of the subjects. Spectral EEG analysis was performed throughout the investigations. In meditation, differential activity was seen, with the noticeable exception of V1, in the posterior sensory and associative cortices known to participate in imagery tasks. In the resting state of normal consciousness (compared with meditation as a baseline), differential activity was found in dorso-lateral and orbital frontal cortex, anterior cingulate gyri, left temporal gyri, left inferior parietal lobule, striatal and thalamic regions, pons and cerebellar vermis and hemispheres, structures thought to support an executive attentional network. The mean global flow remained unchanged for both subjects throughout the investigation (39+/-5 and 38+/-4 ml/100 g/min, uncorrected for partial volume effects). It is concluded that the (H2)15O PET method may measure CBF distribution in the meditative state as well as during the resting state of normal consciousness, and that characteristic patterns of neural activity support each state. These findings enhance our understanding of the neural basis of different aspects of consciousness.     

Nanoindentation analysis of the mechanical behavior of Zr-based metallic glasses with Sn, Ta and W additions

Zr₅₇Cu₂₀Al₁₀Ti₈Ni₅ and modified composition by adding Sn, W or Ta are studied using standard mechanical test and nanoindentation. Addition of refractory elements with a Sn micro-addition increases clearly the Young's modulus and the hardness of basic BMG. However, Sn reduces plasticity. Moreover these experiments allowed, in confine plasticity conditions, estimating an apparent activation volume associated to a plastic deformation (≈150 Å³).