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排序方式: 共有819条查询结果,搜索用时 15 毫秒
791.
792.
Removal of excess fluoride from groundwater using natural coagulant Moringa oleifera Lam and microfiltration 下载免费PDF全文
793.
The sintering behavior of alumina containing different amounts of calcium–aluminum–silicate glass as sintering aid was analyzed under AC electric fields between 0 and 150 V/cm. Liquid phase sintering was enhanced by the electric field, and “flash sintering” behavior depending on the current density and power dissipation within the specimen could be observed. Current flowed only through the liquid phase at high temperature and enhanced the densification process by two effects: Joule heating and athermal response of the viscous liquid under the electric field. Joule heating increased the temperature within the specimen, whereas the applied electric field reduced the viscosity of the liquid phase promoting a more effective matter transport. 相似文献
794.
Roberta de Oliveira Resende Ribeiro Eliane Teixeira Mársico Carla da Silva Carneiro Maria Lúcia Guerra Monteiro Carlos Adam Conte Júnior Sérgio Mano Edgar Francisco Oliveira de Jesus 《LWT》2014
This study evaluated the possibility of differentiating the botanical origin of honeys using Low Field Nuclear Magnetic Resonance (LF 1H NMR). Eighty samples of honey from 8 different botanical sources (eucalyptus, “assa-lipto”, oranges, Barbados cherry, cashew tree, “assa-peixe”, “cipó-uva” and polyfloral) were analyzed. A close correlation (p < 0.01) was established between the LF 1H NMR analysis and physical and chemical measurements, including water content, water activity, pH and color. Bi-exponential fitting of the transverse relaxation (T2) data revealed two water populations in all samples, T21 and T22, corresponding to relaxation times of 0.6–1.8 ms and 2.3–5.4 ms respectively. The observed differences in the relaxation times suggest that these were influenced by the differences in botanical origins. Good linear correlations were observed between the T2 and T21 parameters and the physical and chemical data. This study demonstrated that LF 1H NMR can be a viable technique for use in classifying honeys by their botanical origin. 相似文献
795.
Comparative study by computed radiography,histology, and scanning electron microscopy of the articular cartilage of normal goats and in chronic infection with caprine arthritis‐encephalitis virus 下载免费PDF全文
Videlina Rodrigues de Sousa Francisco das Chagas Araújo Sousa Osmar Ferreira da Silva Filho Rose Eli Grassi Rici Anaemilia das Neves Diniz Laécio da Silva Moura Jacyara de Jesus Rosa Pereira Alves Antônio de Sousa Júnior Maria Angélica Miglino João Macedo de Sousa Felipe de Jesus Moraes Junior Flávio Ribeiro Alves 《Microscopy research and technique》2014,77(1):11-16
In the northeast of Brazil, caprine arthritis‐encephalitis (CAE) is one of the key reasons for herd productivity decreasing that result in considerable economic losses. A comparative study was carried out using computed radiography (CR), histological analysis (HA), and scanning electronic microscopy (SEM) of the joints of CAE infected and normal goats. Humerus head surface of positive animals presented reduced joint space, increased bone density, and signs of degenerative joint disease (DJD). The carpal joint presented no morphological alterations in CR in any of the animals studied. Tarsus joint was the most affected, characterized by severe DJD, absence of joint space, increased periarticular soft tissue density, edema, and bone sclerosis. Histological analysis showed chronic tissue lesions, complete loss of the surface zone, absence of proteoglycans in the transition and radial zones and destruction of the cartilage surface in the CAE positive animals. Analysis by SEM showed ulcerated lesions with irregular and folded patterns on the joint surface that distinguished the limits between areas of normal and affected cartilage. The morphological study of the joints of normal and CAE positive goats deepened understanding of the alteration in the tissue bioarchitecture of the most affected joints. The SEM finding sustained previous histological reports, similar to those found for rheumatoid arthritis, suggesting that the goat infected with CAE can be considered as a potential model for research in this area. Microsc. Res. Tech. 77:11–16, 2014. © 2013 Wiley Periodicals, Inc. 相似文献
796.
Mahnaz Esteki Bahman Farajmand Yadollah Kolahderazi Jesus Simal-Gandara 《Food Analytical Methods》2017,10(10):3312-3320
Adulteration of almond powder samples with apricot kernel was solved by gas chromatographic fatty acid fingerprinting combined with multivariate data analysis methods (principal component analysis (PCA), PCA-linear discriminant analysis (PCA-LDA), partial least squares (PLS), and LS support vector machine (LS-SVM). Different almond and apricot kernel samples were mixed at concentrations ranging from 10 to 90% w/w. PCA and PCA-LDA methods were applied for the classification of almonds, apricot kernels, and mixtures. PLS and LS-SVM were used for the quantification of adulteration ratios of almond. Models were developed using a training data set and evaluated using a validation data set. The root mean square error of prediction (RMSEP) and coefficient of determination (R 2) of validation data set obtained for PLS and LS-SVM were 5.01, 0.964 and 2.29, 0.995, respectively. The results showed that the methods can be applied as an effective and feasible method for testing almond adulteration. 相似文献
797.
Alberto Clemente Francisco Balas M. Pilar Lobera Silvia Irusta Jesus Santamaria 《Aerosol science and technology》2013,47(8):867-874
A long-lasting generator of continuous silica nanoparticle aerosols based in a fluidized bed of glass beads coated with nanosized silica has been developed. The attrition resulting from the bubbling fluidized bed regime progressively detaches the silica coating from the glass beads, giving rise to a steady production of silica nanosized aerosols with median diameters from 100 to 250 nm depending on the initial size of the coating nanoparticles. Continuous aerosol production could be maintained for more than 12 h, and the nanoparticle concentration can be easily tuned in the range of 2000 to 14,000 #/cm3 by adjusting the fluidization and/or dilution flow rates. Copyright 2013 American Association for Aerosol Research 相似文献
798.
Domenic Prete Elisabetta Dimaggio Valeria Demontis Valentina Zannier Maria Jesus Rodriguez-Douton Lorenzo Guazzelli Fabio Beltram Lucia Sorba Giovanni Pennelli Francesco Rossella 《Advanced functional materials》2021,31(37):2104175
Semiconductor nanostructures have raised much hope for the implementation of high-performance thermoelectric generators. Indeed, they are expected to make available reduced thermal conductivity without a heavy trade-off on electrical conductivity, a key requirement to optimize the thermoelectric figure of merit. Here, a novel nanodevice architecture is presented in which ionic liquids are employed as thermally-insulating gate dielectrics. These devices allow the field-effect control of electrical transport in suspended semiconducting nanowires in which thermal conductivity can be simultaneously measured using an all-electrical setup. The resulting experimental data on electrical and thermal transport properties taken on individual nanodevices can be combined to extract ZT, guide device optimization and dynamical tuning of the thermoelectric properties. 相似文献
799.
Julio C. Rosas-Caro Jesus E. Valdez-Resendiz Jonathan C. Mayo-Maldonado Victor M. Sanchez Adolfo R. Lopez-Nuñez Romeli Barbosa Leonardo J. Valdivia 《International Journal of Hydrogen Energy》2021,46(51):26126-26137
This work introduces the development of a power-electronics customizable energy system for their application on renewable energy generation based on proton-exchange membrane fuel cells. The customizable energy system aims to regulate the output voltage from a fuel cell, which has a relatively low amplitude and wide range of variation, to a fixed voltage to feed a grid-tie inverter. The customizable energy system proposed is based on a dc-dc converter for which different configurations (topologies) are available, such as the traditional single-phase boost or the (interleaved) multi-phase boost. The dc-dc converter of the energy system is based on the series-capacitor boost converter, a recently proposed converter that has a similar configuration to the interleaved boost converter. This article shows that the series-capacitor boost topology offers benefits in the proposed application. An experimental prototype was developed and tested in order to demonstrate the advantages of the system proposed. 相似文献