Investigation of the mechanism of sediment formation in residual oil hydrocracking process through characterization of sediment deposits

In deep conversion of petroleum residues by hydrocracking, the refiners often face the problem of sediment or sludge formation, which causes equipment fouling and catalyst deactivation and leads to enormous financial burden in terms of increased costs of operation, maintenance and shutdown. The primary objective of the present study was to obtain information on the composition and structure of the sediments and to understand the mechanism of their formation. Two samples of coke-like sediments, one collected from an industrial vacuum residue hydrocracking unit, and the other produced in pilot plant experiments with the same industrially used feedstock (VR from Kuwait export crude), were analyzed by chemical analysis as well as by various other techniques, such as TGA, NMR, and FT-IR. Prior to analyses, the sediments were fractionated by sequential extraction with heptane, toluene, and tetrahydrofuran. Structural characterization of the sediment material showed the presence of a variety of polyaromatic structures with different degrees of condensation and alkyl substitution. Presentations of average molecular structures were constructed for a number of fractions, such as heptane soluble (HS, 38 wt.%), heptane insoluble–toluene soluble (HIS–TS, 31 wt.%) and tetrahydrofuran insoluble (THFIS, 28 wt.%), separated from the pilot plant sediment. The HIS–TS fraction contained a modified asphaltene-like material. It was more aromatic and contained shorter aliphatic chains than the asphaltenes obtained from VR. The presence of a large amount of HIS–TS modified asphaltenes in the pilot plant sediment suggests that asphaltenes play a key role in the initial stage of sediment formation. The industrial sediment, which underwent severe cracking and condensation reactions on prolonged exposure to high temperature conditions, was highly carbonized (THFIS, 82 wt.%).     

内蒙古鄂尔多斯地区酸粥真菌多样性研究

以内蒙古鄂尔多斯地区的3种酸粥为研究对象,采用Illumina Miseq高通量测序技术与传统微生物学手段相结合的方法对其真菌多样性进行研究。结果表明,3种酸粥样品中存在着大量共有真菌菌群,其优势真菌主要由隶属于子囊菌门（Ascomycota）的假丝酵母属（Candida）和耐碱酵母属（Galactomyces）以及隶属于担子菌门（Basidiomycota）的毛孢子菌属（Trichosporon）构成,三者平均相对含量分别为84.30%、11.86%和3.45%;同时从3种酸粥样品中共分离出9株酵母菌,经分子生物学鉴定为茶叶籽酵母（Meyerozyma caribbica）、索拉尼假丝酵母（Candida solani）、库德毕赤酵母（Pichia kudriavzevii）、白地霉（Galactomyces candidum）、解脂耶氏酵母（Yarrowia lipolytica）和隐球酵母（Cryptococcus albidus）各1株以及近平滑假丝酵母（Candida parapsilosis）2株。     

蒲公英萜醇对人乳腺癌细胞MCF-7增殖及凋亡的影响

目的：探讨蒲公英萜醇对人乳腺癌细胞MCF-7增殖、凋亡的影响及其可能的分子机制。方法：体外培养人 乳腺癌细胞MCF-7,采用噻唑蓝比色法和平板克隆实验检测蒲公英萜醇对MCF-7细胞增殖的影响;Hoechst 33342荧 光染色法检测细胞凋亡的形态变化;Western blot法检测凋亡相关蛋白的表达。结果：蒲公英萜醇对人乳腺癌细胞 MCF-7有明显的增殖抑制作用（P＜0.05）;Hoechst染色结果显示,给药后细胞核内染色质凝集,核固缩,可见凋 亡小体;Western blot结果显示,蒲公英萜醇可极显著提高Bax/Bcl-2的比值（P＜0.01）以及上调活化型Caspase-3/9 的表达（P＜0.01）,下调PARP的表达（P＜0.01）。结论：蒲公英萜醇能够明显抑制人乳腺癌细胞MCF-7增殖, 并通过线粒体途径诱导其凋亡。     

Characterization of the rheological and mechanical properties of shear thickening fluid-coated Twaron® composite

The effects of the weight fraction (concentration) and silica particle size on steady and dynamic rheological responses of shear thickening fluids (STFs) and the quasi-static (QS) penetration resistance of Twaron®/STF composites have been investigated. The STFs have been made by mechanically dispersing 12 or 60 nm silica particles in polyethylene glycol with molecular weight of 400 gr/mol at three different concentrations. Rheological results indicate that with the increase in the concentration of silica in the STF, the critical shear rate (onset of shear thickening) diminish, the initial, critical, and ultimate viscosities increase and the slope of the shear thinning and shear thickening regions tend to be more steeper. Regarding STFs with larger particle sizes, critical shear rate, the initial, critical, and ultimate viscosities as well as the viscoelastic modules diminish. Addressing the Twaron®/STF composite, the increase in STF concentration and reduction in the silica particles size contribute to considerable increase in the puncture characteristics. The most noticeable puncture characteristics turn out in the case of 35 wt. % STF/Twaron® composites containing 12 nm particles in which the maximum bearable load and the maximum absorption energy are nearly 3.6 and 2.3 times larger than those of the neat Twaron®.     

Encapsulation of Coumarin 151 into the mesopores of modified rodlike SBA-15

Dye Coumarin 151 was postgrafted into the rodlike SBA-15 mesoporous materials, which were synthesized by a direct hydrothermal synthesis method and further modified by an organic silane with a terminal amino group. Characterization by powder X-ray diffraction, N₂ adsorption-desorption, transmission electron microscopy, photoluminescence and scanning electron microscopy were carried out. Small-angle X-ray diffraction and N₂ adsorption-desorption characterizations showed that these dye containing materials remained as ordered mesostructures and the pore size was from 6 nm for blank sample to 3.6 nm for postgrafting sample. PL characterization of composite samples exhibited optical properties with different dye concentrations. The characterization showed the existence of Coumarin 151 in the channels of SBA-15 and the composite materials with novel optical properties enabled possible applications in optical sensing and electron acceptors.     

A generalized coefficient of performance for conditioning moist air

The psychrometric chart is a useful tool for calculating the energy change between any two states and visually identifying the contribution of ‘sensible’ and ‘latent’ effects. However, the amount of work needed to move from one state to another is not read directly from the chart. In this paper, temperature and vapor pressure changes are cast into terms of minimum work relative to a dead state, and work contours are plotted on the psychrometric chart. These contours show the minimum work needed to move the state of the air further from the ambient conditions or the maximum work produced by letting a state approach the ambient conditions. A dividing line between heat pump and refrigeration operation is set on the basis total energy of the conditioned space relative to the ambient. Finally, an example is used to illustrate the implementation of the analysis.     

Representativeness of clinical samples of youths with mental disorders: A preliminary population-based study.

In a household community sample of 1,285, 9–17 year-olds with mental disorders who had received outpatient specialty mental health services in the past year were compared with youths with mental disorders who had not received those services to determine if samples drawn from clinical settings are representative of youths with mental disorders in the general population. Those who had used services were more impaired, less competent, more likely to have comorbid disorders, more likely to belong to non-Hispanic White relative to other ethnic groups, and less likely to be prepubertal girls. Their parents were more educated, but less satisfied with family life, engaged in less monitoring of their children, and more likely to have used mental health services themselves. These findings suggest the hypothesis that samples of youths with mental disorders drawn from outpatient clinical settings are not representative of all youths with mental disorders. If confirmed, this would indicate the importance of population-based samples for the study of psychopathology in youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Closure of nasal septal perforations

Polymorphism of factor H (HF) was investigated in 1060 unrelated Japanese individuals using isoelectric focusing and immunoblotting. Besides 6 different HF types a null type and an unusual type were observed. The family analysis suggested the hereditary occurrence of a new variant allele HF*C. The population data fitted the Hardy-Weinberg equilibrium, assuming that the null allele HF*QO occurs commonly. The allele frequencies were HF*A = 0.407 +/- 0.011, HF*B = 0.491 +/- 0.011, HF*A1 = 0.011 +/- 0.002 and HF*QO = 0.091 +/- 0.006. The HF polymorphism in Japanese was shown to be controlled by the above 4 common alleles.     

Thermal conductivity of a mixture of helium and air

The thermal conductivity of a helium-air mixture was measured for molar concentrations from 0 to 100%.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 38, No. 4, pp. 634–638, April, 1980.