Urban adolescents' constructions of supports and barriers to educational and career attainment.

This study presents the educational and career goals and perceptions of supports and barriers related to these goals as described in semistructured interviews of 16 students from diverse racial and ethnic backgrounds attending 9th grade at an urban public high school in a large Northeastern city. Using consensual qualitative research (CQR) methodology (C. E. Hill et al., 2005), the authors identified categories and subcategories to students' perceptions of barriers and supports. The findings highlight students' understanding of how their proximal contexts serve potentially as both supports and barriers. Implications for educational and career interventions are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An adaptive tabu search approach for buffer allocation problem in unreliable non-homogenous production lines

The buffer allocation problem, i.e. how much buffer storage to allow and where to place it within the line, is an important research issue in designing production lines. In this study, a novel adaptive tabu search approach is proposed for solving buffer allocation problem in unreliable and non-homogeneous production lines. The objective is to maximize the throughput of the line, which is constrained by the capacity of each buffer space and also the total buffer capacity to allocate to these spaces. Besides proposing a new strategy to tune the parameters of tabu search adaptively during the search, an experimental study is carried out to select an intelligent initial solution scheme among three alternatives so as to decrease the search effort to obtain the best solutions. The performance of the proposed approach is evaluated by computational tests and very promising results are obtained.     

Valorisation of almond shell waste in ultrasonic biomordanted dyeing: alternatives to metallic mordants

An agroindustrial waste, outer green shell of almond fruit has been valorised as a novel natural dye using chemical solvent-free extraction, small amount of metallic mordants, one-bath biomordanted dyeing, ultrasonic medium, auxiliary-free dyeing and washing. The main objective of this study is to evaluate biomordants vs. metallic mordants depending on heating system both in extraction and dyeing and to reveal alternatives to metallic mordants. Effects of conventional- and ultrasound-assisted systems on dyeing and fastness properties were investigated. Wool fabrics dyed using metallic mordants (alum, iron II sulphate, copper II sulphate and potassium dichromate) were compared with the samples dyed in conjunction with biomordants [powder of valex (acorn of Quercus ithaburensis ssp. macrolepis), pomegranate (Punica granatum L.) rind, rosemary (Rosmarinus officinalis) and thuja (Thuja orientalis) leaves] in terms of colour yield, colour coordinates and fastness properties. Heating system had significant effects on dyeing and fastness results. Power ultrasound did not present any advantage in colour yield increment while it presented different effects on fastness values depending on mordant and process type of which ultrasound was applied. Some biomordants could be replaced with metallic mordants depending on their types and heating system. They could produce completely different colour gamuts just like metallic mordants.     

Effects of meteorological variables on exergetic efficiency of wind turbine power plants

This present paper deals with exergy efficiency results of the Wind Turbine Power Plants (WTPPs). Effects of meteorological variables such as air density, pressure difference between state points, humidity, and ambient temperature on exergy efficiency are discussed in a satisfactory way. Some key parameters are given monthly for the three turbines. Exergy efficiency differs from 0.23 to 0.27 while temperature is changing from 268.15 K to 308.15 K with air density 1.368–1.146 (kg/m³). While pressure difference (ΔP) between inlet and outlet of the turbine differs from 100 to 1100 (Pa), exergy efficiency decreases fairly for different wind speeds. While specific humidity is changing from 0.001 to 0.015 (kg_water/kg_{dry air}), exergy efficiency decreases gently. Generally these meteorological variables are neglected while planning WTPPs, but this neglect can cause important errors in calculations and energy plans. Obtained results indicate that while planning WTPPs meteorological variables must be taken into account.     

Effects of sintering and zirconmullite doping on nanostructural vacancies of bovine hydroxyapatite by positron techniques

In this study, the nanostructural vacancy behavior of bovine derived hydroxyapatite (BHA) doped with powder zirconmullite (ZM) contents of 5, 7.5, 10 and 12.5 wt.% were presented at sintering temperatures of 1000, 1100, 1200 and 1300°C. ZM-doped BHA (ZM-BHA) was characterized by X-ray diffraction and positron annihilation lifetime spectroscopy (PALS). Density and hardness behavior were measured with respect to increasing sintering temperature. PALS results indicate that the longest lifetime component τ₃ of ortho-positronium (o-Ps) localized at open spaces is attributed to the vacancy site and almost constant with the ZM contents and the sintering temperatures to have a mean value of 0.680 ns (corresponding to the radius of 0.997 nm). This average value is ascribed to the OH group defects along the main crystalline line. On the other hand, the o-Ps intensity attributed to the number of vacancy sites increases almost linearly with ZM additives and sintering temperatures. The intensity is also related to the density and hardness of ZM-BHA in terms of ZM contents.     

Selective extraction of phosphatidylcholine from lecithin by supercritical carbon dioxide/ethanol mixture

Selective extraction of phosphatidylcholine (PC) from deoiled soybean lecithin using supercritical fluid (SCF) mixtures of carbon dioxide (CO₂) and ethanol was studied at moderate pressures. Temperature was varied between 60 and 80°C at pressures of 17.2 and 20.7 MPa. Ethanol was added as co-solvent to supercritical CO₂ at the levels of 10 and 12.5 wt%. Constant rate of extraction of the individual phospholipids (PL) was observed for 150 min during which the extractions were carried out. Pressure and ethanol fraction had a positive effect on the selective extraction of PC, whereas temperature had a negative effect. Under all the conditions studied, the extracts were mainly composed of PC while the extraction of the other PL was very low. Extraction at 60°C and 20.7 MPa with 10 wt% ethanol/90 wt% CO₂ SCF mixture resulted in 95% selectivity to PC.     

基于回归分析的三次产业产值研究

在国民经济的研究中,三次产业的产值反映了GDP的大小,预测三次产业的产值对GDP的预测起着至关重要的作用.基于1981年到2012年的统计数据,建立了指数回归模型.研究表明：通过指数回归模型,预测第一、第三产业产值的相对误差小于0.07,该模型对三次产业产值的预测具有很高的使用价值.     

An Omniphobic Spray Coating Created from Hierarchical Structures Prevents the Contamination of High-Touch Surfaces with Pathogens

Engineered surfaces that repel pathogens are of great interest due to their role in mitigating the spread of infectious diseases. A robust, universal, and scalable omniphobic spray coating with excellent repellency against water, oil, and pathogens is presented. The coating is substrate-independent and relies on hierarchically structured polydimethylsiloxane (PDMS) microparticles, decorated with gold nanoparticles (AuNPs). Wettability studies reveal the relationship between surface texturing of micro- and/or nano-hierarchical structures and the omniphobicity of the coating. Studies of pathogen transfer with bacteria and viruses reveal that an uncoated contaminated glove transfers pathogens to >50 subsequent surfaces, while a coated glove picks up 10⁴ (over 99.99%) less pathogens upon first contact and transfers zero pathogens after the second touch. The developed coating also provides excellent stability under harsh conditions. The remarkable anti-pathogen properties of this surface combined with its ease of implementation, substantiate its use for the prevention of surface-mediated transmission of pathogens.