Efficient catalytic performance of tetra-alkyl orthotitanates for the oxidative desulfurization of dibenzothiophene at room temperature

Desulfurization of fuel oil is of great importance for producing clean energy. In this study, we report that tetra-alkyl orthotitanates exhibited efficient catalytic performance in the oxidative desulfurization of dibenzothiophene. The sulfur content in model oil (1000 ppmw) could be reduced to less than 10 ppmw within 10 min at room temperature and ambient pressure. In addition, the formed sulfones can be easily separated from the oil phase without extraction process. This work will provide a basis for the design of novel oxidative desulfurization catalysts with high desulfurization efficiency.     

基于低场核磁共振的抚顺油页岩孔隙连通性演化研究

油页岩原位注热开采过程中，储层内部孔隙结构的连通性直接影响载热介质的流动行为和传热效率，同时对油气产物的扩散和流动行为起控制作用.本文利用低场核磁共振（LF NMR）技术，考察了不同热解终温（23~650℃）处理时，饱和水及束缚水状态下抚顺油页岩的T₂谱，分析了可动流体T₂截止值、束缚流体孔隙度、饱和流体孔隙度、渗透率等NMR孔隙参数，定量研究了随热解终温升高，抚顺油页岩孔隙结构的连通性演化规律.研究结果表明热解终温对抚顺油页岩孔隙连通性及渗透率的变化起控制作用，且可动流体孔隙度对总孔隙度的增加起主要促进作用，这说明热解终温升高加大了渗透率及油气产物的输运能力.本文为深入认识油页岩原位热解过程中孔隙结构的演化提供了依据.     

缝洞型碳酸盐岩油藏注水驱油提高采收率研究

Y油田为缝洞型碳酸盐岩油藏,油藏复杂的地质特征决定了其开发模式有别于常规砂岩油藏.为了有效提高Y油田采收率,利用Eclipse数值模拟软件建立了地质模型,对水平井长度、射孔间距及酸压缝长等油藏产能影响因素与转注时机、注采比以及关井时间等注采参数进行了优化.结果认为:对于Y缝洞型碳酸盐岩油藏,水平井水平段长度为500m、射孔间距为20m或酸压规模为100m时,累计产油量可达到最大值;压力降至废弃压力时进行转注,可获得最大采收率;周期注采比等于1时,周期时效与累计增油量达到最大值;关井时间为8天时,采收率提高幅度最大.     

柠檬果茶中游离态和键合态挥发性成分分析

以柠檬果茶为研究对象,建立了顶空固相微萃取前处理结合气相色谱质谱联用技术测定其中挥发性化合物的分析方法。采用开水冲泡对样品进行提取,通过Amberlite XAD-2大孔吸附树脂对柠檬果茶中的糖苷类挥发性组分键合,分离游离态和键合态化合物,甲醇溶剂作为洗脱剂对键合态化合物进行洗脱,Almondsβ-D-葡萄糖苷酶对其酶解。使用气质联用对样品中游离态和键合态挥发性成分进行检测,其结果根据数据库匹配和对比文献保留时间定性,内标法进行定量。结果表明,柠檬果茶中含有游离态物质24种,键合态物质16种,主要为(+)-柠檬烯、1-辛醇、橙花醇、(-)-4-萜品醇、alpha-松油醇等。方法为花果茶干燥工艺提供参考。     

Illuminating the flesh of bone identification – An application of near infrared spectroscopy

Near infrared (NIR) reflectance spectroscopy coupled with chemometric analysis was evaluated as a non-destructive tool to discriminate skull bone samples from different animal species. In total 70 skull bones from animals of three classes (mammalians, avian and reptiles) were scanned in the wavelength range between 950 to 1650 nm. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to analyse the NIR spectra of the skull samples. Correct classification rates of 96% and 81% were obtained for the classification of skull bone samples according to avian and mammalian classes, respectively. Overall, a 91% correct classification rate was obtained for the classification of skull samples according to the class (mammalian and avian). This study demonstrates the potential of NIR spectroscopy coupled with chemometric as data processing, as a means of a rapid, non-destructive classification technique for skull bone samples.     

Rapid Simultaneous Determination of Volatile Organic Compounds in Mattress Fabric by Headspace–Gas Chromatography–Mass Spectrometry

An analytical method for simultaneously determining 32 volatile organic compounds in mattress fabrics based on static headspace coupled to gas chromatography and mass spectrometry detection was established. Samples were cut into 5?×?5?mm small pieces and placed in a 20?mL headspace vial at 90° for 30?min. To achieve the optimum conditions for the analysis, several parameters including the heating temperature, heating time, sample weight, and injection time were investigated. The results demonstrated that the most important parameter influencing the sensitivity of the analysis was the heating temperature. The optimum method showed good linearities with correlation coefficients ranged from 0.9944 to 0.9998. The limits of detection and quantification for the target compounds were in the ranges of 0.004–0.032 and 0.013–0.099?µg/?g, respectively. The method was successfully applied to determine the volatile organic compounds in six categories of mattress fabrics. The results showed that some volatile organic compounds were found, such as naphthalene, hexadecane, and 1,4-diisopropylbenzene. Moreover, the concentrations of 32 volatile organic compounds decreased following the order of jute, terylene, polyester, velboa, nylon, and cotton samples in the study. These results indicated that the method is fast, accurate, and successful for determining volatile organic compounds in mattress fabrics.     

Multidimensional Gas Chromatography–Mass Spectrometry Method for Fingerprinting Polycyclic Aromatic Hydrocarbons and Their Alkyl-Homologs in Crude Oil

The composition of polycyclic aromatic hydrocarbons in crude oil is usually too complex to use standard capillary gas chromatography to separate all of the components. In this study, a multidimensional gas chromatography–mass spectrometry (GC-MS) technique was used to analyze polycyclic aromatic hydrocarbon fractions of crude oil collected from the Dongying oil field in the Bohai Sea. A DB-17MS column (30?m?×?0.25?mm?×?0.25?µm) was used as a prefractionating column and only selected heart-cuts were transferred to the second chromatographic dimension (HP-5MS, 15?m?×?0.25?mm?×?0.25?µm) by a pressure-adjusted continual flow-type switching device for quantification of the polycyclic aromatic hydrocarbons. The chromatographic elements and parameters, such as detector selection and column combinations, were optimized. Naphthalene, phenanthrene, fluorene, dibenzothiophene, chrysene, and their C₁–C₄ alkyl homologs were identified. The profile of the polycyclic aromatic hydrocarbons obtained using the multidimensional GC-MS method was compared with the results obtained by traditional one-dimensional GC-MS.     

Phytochemical analysis of Saponaria officinalis L. shoots and flowers essential oils

Phytochemical analysis by GC and GC/MS of the essential oil samples obtained from fresh shoots and flowers of Saponaria officinalis L. allowed the identification of 96 components in total, comprising 94.7% and 86.0% of the total oils compositions, respectively. Regarding the shoots essential oil, the major of 87 identified volatile compounds were phytol (14.1%), tricosane-6,8-dione (13.4%), patchouli alcohol (7.9%) and tricosane (7.2%), whereas patchouli alcohol (20.0%), heneicosane (11.5%) and tricosane (8.4%) were dominant among the 66 volatiles in the flower oil. Nonterpenoid compounds had the highest contribution in S. officinalis shoots essential oil (53.7%), while in the flower oil, constituents were almost evenly distributed between the oxygenated sesquiterpenoid (41.2%) and nonterpenoid compounds (39.5%).     

Asymptotic properties of the growth curve model with covariance components

We consider a multivariate regression (growth curve) model of the form , where and are unknown scalar covariance components. In the case of replicated observations, we derive the explicit form of the locally best estimators of the covariance components under normality and asymptotic confidence ellipsoids for certain linear functions of the first order parameters {B _ij} estimating simultaneously the first and the second order parameters.     

Development of a membrane-based vapor-phase bioreactor

A vapor-phase bioreactor has been developed utilizing porous metal membranes in a cylindrical design employing radial flow as opposed to traditional axial flow for the vapor stream. The system was evaluated for the biodegradation ofp-xylene (p-xylene) from a water-saturated air stream byPseudomonas putida ATCC 23973 immobilized onto sand. The biocatalyst was placed in the annular space between two cylindrical, porous stainless-steel membranes. Details of the reactor system are presented along with biological data verifying system performance. The feed flow rate andp-xylene concentration were varied between 60 and 130 cm³/min and 15–150 ppm, respectively. Continuous reactor operation was maintained for 80–200 h with removal efficiencies (based onp-xylene disappearance) between 80 and 95%. The effluent concentration histories were compared to determine the operating range of the bioreactor.