82 research outputs found

    Higher harmonics of ac voltage response in narrow strips of YBa2Cu3O7 thin films: Evidence for strong thermal fluctuations

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    We report on measurements of higher harmonics of the ac voltage response in strips of YBa2Cu3O7 thin films as a function of temperature, frequency and ac current amplitude. The third (fifth) harmonic of the local voltage is found to exhibit a negative (positive) peak at the superconducting transition temperature and their amplitudes are closely related to the slope (derivative) of the first (Ohmic) harmonic. The peaks practically do not depend on frequency and no even (second or fourth) harmonics are detected. The observed data can be interpreted in terms of ac current induced thermal modulation of the sample temperature added to strong thermally activated fluctuations in the transition region.Comment: 9 pages, 4 figures (PDF file

    Microstructure and flow properties of lyophilized mango pulp with maltodextrin.

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    <div><p>ABSTRACT The present study had as objective to determine the flow properties and behavior of lyophilized mango pulp powder as a function of different concentrations of maltodextrin. In the samples of the powders contain 5, 10 and 15% of maltodextrin the angle of effective internal friction, wall friction angle, flow index and bulk density were determined. The microstructure was evaluated by scanning electron microscopy. The freeze-dried samples are characterized as having an amorphous structure, and the drying aid used modified the surface of the particles. The flow index was 3.19, 4.28 and 4.53 for samples containing, respectively, 5, 10 and 15% maltodextrin. Increasing the concentration of maltodextrin in the mango pulp decreased the effective angles of internal friction and wall friction. The bulk density of the powders increased with increasing concentration of maltodextrin for the samples containing 5, 10 and 15% of the maltodextrin, being equal to 597.8, 689.8 and 691.3 kg m-3, respectively. Thus, it was concluded that the addition of maltodextrin modified the shape of the particles, decreased segregation, affected the flow properties of the mango powders, facilitating flow and increasing their bulk density.</p></div

    Aplicação do plano APPCC para polpas de frutas mistas congeladas com perfil funcional.

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    Stability and microstructure of powdered pulp of the Palmer mango obtained by the process of lyophilisation.

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    ABSTRACT The aim of this work was to study the stability of powdered mango pulp obtained through the process of lyophilisation, as well as its structural characteristics using electron microscopy analysis. In response to an earlier experimental design using maltodextrin concentrations of 0%, 10%, 20% and 30% and periods of 24 and 30 hours, the condition of 20% maltodextrin and 24 hours drying was chosen as the best for drying mango in a freeze dryer. The stability study was therefore carried out using powdered mango pulp obtained under the above best-drying conditions, stored for 90 days and monitored every two weeks by analysis of the moisture, ascorbic acid content, b* colorimetric parameter and hygroscopicity. Storage was at room temperature (27 °C) in vacuum and non-vacuum laminated packaging, and in non-vacuum plastic packaging. The vacuum laminated packaging maintained the initial characteristics of the stored product for longer, especially the ascorbic acid content, hygroscopicity and b* colour parameter. The microstructure of the sample was then studied under different concentrations of maltodextrin (0%, 10%, 20% and 30%) so as to understand the effect of the drying agent on the final product. Close-up images of the powder revealed the porous surface formation and the effect of the agent on particle size, where higher concentrations of maltodextrin resulted in more porous powders with smaller particles.</div

    Genetic Survey of Psilocybe Natural Products

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    Psilocybe magic mushrooms are best known for their main natural product, psilocybin, and its dephosphorylated congener, the psychedelic metabolite psilocin. Beyond tryptamines, the secondary metabolome of these fungi is poorly understood. The genomes of five species ( P. azurescens , P. cubensis , P. cyanescens , P. mexicana , and P. serbica ) were browsed to understand more profoundly common and species‐specific metabolic capacities. The genomic analyses revealed a much greater and yet unexplored metabolic diversity than evident from parallel chemical analyses. P. cyanescens and P. mexicana were identified as aeruginascin producers. Lumichrome and verpacamide A were also detected as Psilocybe metabolites. The observations concerning the potential secondary metabolome of this fungal genus support pharmacological and toxicological efforts to find a rational basis for yet elusive phenomena, such as paralytic effects, attributed to consumption of some magic mushrooms

    Effective Area-Elasticity and Tension of Micro-manipulated Membranes

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    We evaluate the effective Hamiltonian governing, at the optically resolved scale, the elastic properties of micro-manipulated membranes. We identify floppy, entropic-tense and stretched-tense regimes, representing different behaviors of the effective area-elasticity of the membrane. The corresponding effective tension depends on the microscopic parameters (total area, bending rigidity) and on the optically visible area, which is controlled by the imposed external constraints. We successfully compare our predictions with recent data on micropipette experiments.Comment: To be published in Phys. Rev. Let

    Bebida vegetal de amêndoa de castanha-de-caju desenvolvida pela Embrapa comparada a produto comercial.

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    A Embrapa desenvolveu o processo de uma bebida à base de amêndoa de castanha-de-caju, em que a amêndoa é triturada com água, na proporção de 1:10 (m/m), e açúcar (3%), seguindo-se tratamento térmico a 140 °C por quatro segundos. O objetivo deste trabalho foi comparar a bebida vegetal de amêndoa de castanha-de-caju quebrada, obtida por processo da Embrapa, com produto comercial. Observou-se que a bebida desenvolvida na Embrapa apresentou maiores teores de sólidos, cinzas, carboidratos, valor energético e índice de branco. Os atributos sensoriais mostraram maior intensidade de gosto doce, corpo e sabor de amêndoa na bebida da Embrapa e poucas diferenças em relação à homogeneidade, presença de partículas na boca e cor branca. Essas diferenças fizeram com que a bebida da Embrapa apresentasse médias superiores à bebida comercial para a aceitação de aparência, textura, sabor e impressão global. No entanto, não se observou diferença de aceitação para cor e aroma.bitstream/item/224669/1/BP-219.pd
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