Prediction of hourly and daily diffuse fraction using neural network,as compared to linear regression models

For most of the locations all over Egypt the records of diffuse radiation in whatever scale are non-existent. In case that it exists, the quality of these records is not as good as it should be for most purposes and so an estimate of its values is desirable. To achieve such a task, an artificial neural network (ANN) model has been proposed to predict diffuse fraction (K_D) in hourly and daily scale. A comparison between the performances of the ANN model with that of two linear regression models has been reported. An attempt was also done to describe the ANN outputs in terms of first order polynomials relating K_D with clearness index (K_T) and sunshine fraction (S/S₀). If care is taken in considering the corresponding regional climatic differences, these correlations can be generalized and transferred to other sites. The results hint that the ANN model is more suitable to predict diffuse fraction in hourly and daily scales than the regression models in the plain areas of Egypt.     

中心复合设计法研究浆液床反应器的气液传质特性

采用中心复合设计法研究系统压力(P)、气体表观气速(UG)以及固体颗粒体积浓度(Cv)对浆液床中体积气液传质系数(kLa)的影响。在实验中发现,体积气液传质系数随系统压力和气体表观气速的增加而增加,当增加固体颗粒体积浓度时反而下降。在0.1～1.5MPa的压力范围内,甲烷的饱和溶解度遵守亨利定律。     

Effects of current intensity and cumulative exposure time on the localized current-activated sintering of titanium nickelides

This article discusses the processing and properties of titanium nickelides locally sintered via Current-Activated Tip-based Sintering (CATS), a new localized sintering process. One of the advantages of CATS is the ability to apply orders of magnitude higher current densities than conventionally possible, which can promote rapid sintering and phase transformation rates. Mechanically alloyed equi-atomic Ni–Ti powder was for the first time tip sintered at varying current intensities and cumulative current exposure time. The effect of current-control processing conditions on the evolution of the locally sintered Ni–Ti microstructure and properties are discussed. The size of the locally sintered process zone was found to increase with cumulative current exposure time. The degree of sintering, phase transformations, and properties were found to depend on the current intensity, cumulative current exposure time and distance away from the tip/compact interface. Fully/near fully dense material was achieved rapidly at locations exposed to the highest current densities.     

Fabrication and characterization of <Emphasis Type="Italic">Antheraea pernyi</Emphasis> silk fibroin-blended P(LLA-CL) nanofibrous scaffolds for peripheral nerve tissue engineering

Electrospun nanofibers have gained widespreading interest for tissue engineering application. In the present study, ApF/P(LLA-CL) nanofibrous scaffolds were fabricated via electrospinning. The feasibility of the material as tissue engineering nerve scaffold was investigated in vitro. The average diameter increased with decreasing the blend ratio of ApF to P(LLA-CL). Characterization of ¹³C NMR and FTIR clarified that there is no obvious chemical bond reaction between ApF and P(LLA-CL). The tensile strength and elongation at break increased with the content increase of P(LLA-CL). The surface hydrophilic property of nanofibrous scaffolds enhanced with the increased content of ApF. Cell viability studies with Schwann cells demonstrated that ApF/P(LLA-CL) blended nanofibrous scaffolds significantly promoted cell growth as compare to P(LLA-CL), especially when the weight ratio of ApF to P(LLA-CL) was 25:75. The present work provides a basis for further studies of this novel nanofibrous material (ApF/P(LLA-CL)) in peripheral nerve tissue repair or regeneration.     

Magnetite nanoparticles/polyvinyl pyrrolidone stabilized system for corrosion inhibition of carbon steel

The corrosion inhibitive effects of new polyvinylpyrrolidone stabilized crystalline super-paramagnetic nanoparticles (5–20?nm) were investigated. Several characterization techniques confirmed the high stability of the prepared stabilized nanoparticles in solution. The polarization and EIS measurements showed that the inhibition efficiency increased with increasing concentration of the magnetite nanoparticles. The results obtained from EIS and electrochemical polarization curves are in reasonably good agreement. The obtained results suggest that the prepared stabilized system is an excellent inhibitor for carbon steel corrosion in 1?M HCl solution.     

Electrospinning: An emerging technology to construct polymer-based nanofibrous scaffolds for diabetic wound healing

A chronic wound in diabetic patients is a major public health concern withsocioeconomic and clinical manifestations.The underlying medical condition of diabeticpatients deteriorates the wound through physiological,metabolic,molecular,and cellularpathologies.Consequently,a wound enters a vicious pathological inflammatory cycle.Many therapeutic approaches are in practice to manage diabetic wounds hence ensuringthe regeneration process.Polymer-based biomaterials have come up with hightherapeutic promises.Many efforts have been devoted,over the years,to build aneffective wound healing material using polymers.The electrospinning technique,although not new,has turned out to be one of the most effective strategies in buildingwound healing biomaterials due to the special structural advantages of electrospunnanofibers over the other formulations.In this review,careful integration of allelectrospinning approaches has been presented which will not only give an insight intothe current updates but also be helpful in the development of new therapeutic materialconsidering pathophysiological conditions of a diabetic wound.     

Processing of grain-size functionally gradient bioceramics for implant applications

This paper reports work on the processing of functionally gradient alumina bioceramics with a continuously decreasing grain size across the thickness, with the view of ultimately utilizing high-quality nano/ultrafine powders only at the surface of an implant to provide superior wear and mechanical properties. A model of disc geometry is used to examine the feasibility of producing this brand of materials. Wet processing/ball milling and sequential slip casting procedures were used to de-agglomerate alumina powders and deposit green layers of varying particle sizes from 50 to 250 nm. Both pressure-less sintering and hot pressing were evaluated as high temperature sintering/consolidation processes. The results indicate that pressure-less sintering may not be suitable. Hot pressing, however, achieved very promising results producing near fully dense product with a grain size that gradually changes across its thickness.     

Studies on ferrocene and its derivatives. V. Preparation of some new ferrocenyl pyrazolines,pentan-1,5-diones and β-ketosulphides

Ferrocenyl pyrazolines have been prepared by the reaction of ferrocenyl chalcones with diazomethane and/or substituted benzenesulphonyl hydrazides. A Michael reaction on ferrocenyl chalcones using phenyl benzyl ketone and/or thiophenol yielded the corresponding ferrocenyl pentan-1,5-diones and ferrocenyl-β-ketosulphides, respectively.     

Heterocyclic azo dyes. III. Azo Dyes Containing the Benzo-1,2,3-thiadiazole Nucleus

The synthesis, some dyeing and fastness properties of several new dispersed and acid dyes derived from 5-amino-benzo-1,2,3-thiadiazole are described. Comparison between the dyeing properties of some synthesised dyes and other similar dyes is also given.