Enhancement of microcrystalline n-i-p solar cell performance via use of pre-covering layers and H2 treatment

We study the effects of a-Si:H and μc-Si:H covering layers and an H₂ treatment on the characteristics of μc-Si:H thin film solar cells deposited in open single chamber very high frequency plasma enhanced chemical vapor deposition systems. Secondary ion mass spectrometry is used to evaluate the phosphor concentration in the μc-Si:H material. Compared to use of an a-Si:H covering layer, use of a μc-Si:H covering layer reduces dopant contamination by a relative 50%, and improves efficiency by a relative 6%, and use of an H₂ treatment reduces dopant contamination by a relative 64%, and improves efficiency by a relative 17%.     

Photo‐Induced Functionalization of Spherical and Planar Surfaces via Caged Thioaldehyde End‐Functional Polymers

The synthesis and application of a novel reversible addition‐fragmentation chain transfer (RAFT) agent carrying a photocaged thioaldehyde moiety is described (λ_max = 355 nm). RAFT polymerization of styrene, dimethylacrylamide and a glycomonomer is evidenced (3600 g mol^?1 ≤ M_n ≤ 15 000 g mol^?1; 1.07 ≤ ? ≤ 1.20) with excellent end‐group fidelity. The photogenerated thioaldehyde on the chain ends can undergo hetero Diels–Alder reactions with dienes as well as reactions with nucleophiles. The terminal photoreactive polymers are photografted to porous diene‐reactive polymeric microspheres. The grafted particles are in‐depth characterized via scanning electron microscopy, elemental analysis, X‐ray photoelectron spectroscopy, and high resolution FT‐IR microscopy, leading to a qualitative as well as quantitative image of the core–shell objects. Grafting densities up to 0.10 molecules nm^?2 are reached. The versatility of the thioaldehyde ligation is evidenced by spatially resolved grafting of polystyrene onto nucleophilic groups present in poly (dopamine) (PDA)‐coated glass slides and silicon wafers via two‐photon direct laser writing (DLW) imaged by ToF‐SIMS. The combination of thioaldehyde ligation, RAFT polymerization, and DLW allows for the spatially resolved grafting of a vast range of polymers onto various substrates in any desired pattern with sub‐micrometer resolution.     

A methodology for developing product platforms in the specific setting of the housebuilding industry

Platform based strategies have proved to be a successful approach for achieving optimum balances between standardization and variation in many industries. However, application of this concept in the housebuilding industry is relatively new. This article describes a new methodology for developing product platform architectures in the specific setting of the housebuilding industry. This methodology comprises a reference framework describing the basic elements that constitutes a product platform, supported by a protocol for developing product platforms. The applicability of the proposed methodology has been tested at a Dutch housebuilding company. In this study, the methodology demonstrated its added value in determining which modules to standardize and defining a product platform. This article also describes a distinctive method of housing classification that is based on the spatial use of houses. Compared to the traditional classification system based on technical construction elements, the proposed new classification system facilitates a better translation of functional requirements into technical specifications.     

Physical anhedonia and schizophrenia.

Assessed the relation of anhedonia to schizophrenia using 69 schizophrenics and 54 psychiatric control outpatients from 3 mental health centers. In addition to indexes of schizophrenia, each S was given the Physical Anhedonia Scale, a measure of premorbidity, and a vocabulary test. Measures of chronicity and education were also included. ANOVAs indicated no significant differences in anhedonia among 4 diagnostic groups: paranoid schizophrenics, nonparanoid schizophrenics, unipolar affective psychiatric control Ss, and other psychiatric control Ss. Intercorrelations showed that anhedonia was negatively related to premorbid social status, years of education and vocabulary, but it was not significantly related to hospitalization. Data do not support the hypothesis that anhedonia is a consistent sign of schizophrenia but are compatible with the notion that anhedonia is the consequence of such liabilities as psychiatric disturbance, poor premorbid status, low educational level, and low verbal ability. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Body Compositional Changes and Growth Alteration in Chicks from Hens Fed Conjugated Linoleic Acid

Effects of feeding conjugated linoleic acid (CLA) to hens on progeny chick development and composition at hatch (NHC) and three weeks of age (TWC) were assessed. CLA (0 or 0.5%, composed of mixed isomers of cis-9,trans-11 or trans-10,cis-12-CLA) was fed to hens with either safflower (SO) or olive oil (OO) (3 or 3.5%) to assure successful hatch for 2 weeks prior to collection for incubation. Maternal CLA feeding had no effect on hatchability, but improved egg fertility (p < 0.05). Maternal feeding of CLA with SO increased 21 day-old progeny growth, while CLA with OO decreased growth (oil*CLA, p < 0.05). In 25 day-old chicks (TWC), but not NHC, maternal CLA decreased the proportion of total body water (p < 0.05) and increased body ash (p < 0.05). While monounsaturated fatty acids were decreased and saturated fatty acids increased in eggs and NHC from hens fed CLA, no differences in fatty acid composition were observed in chicks at 25 days of age from hens fed CLA. Maternal CLA feeding resulted in the presence of c9,t11 and t10,c12-CLA in NHC, but only c9,t11 in the TWC. In conclusion, hens fed CLA led to improved fertility and altered body composition at 3 weeks of age.     

Copper(I) selenophene-2-carboxylate (CuSC) promoted C–S cross-coupling reaction of thiols with aryl iodides

We reported the synthesis of copper (I)-selenophene-2-carboxylate (CuSC) and application as new catalyst in the cross-coupling reactions of thiols with aryl iodide to afford the corresponding unsymmetrical thioethers. The optimized reaction conditions were applied to thiols and aryl iodides having a wide range of functional groups, including electron rich and electron poor substrates. The chemoselectivity of the reaction with 4-iodobromobenzene and 2-aminothiophenol derivatives was briefly examined through the competitive iodine versus bromine and thiol versus nitrogen cross-coupling.     

Femtosecond Ti: Sa ultra short-pulse laser irradiation effects on the properties and morphology of the zirconia surface after ageing

Femtosecond pulses from a Ti:Sapphire laser were used to irradiate specimens of yttria-stabilised (35% mol) tetragonal zirconia (Y-TZP) with the purpose of studying the effects of the irradiations on their surface properties and morphology after ageing. Zirconia disks were divided into eight groups (n = 32) according to their surface treatment and subsequent ageing: Control: no treatment; sandblasting: Al₂O₃ sandblasting 50 μm; and ultrashort laser pulses irradiation with 25 μJ pulses, considering two different scanning steps based on the width between two grooves. These groups were duplicated and submitted to ageing. The surfaces were analysed using scanning electron microscopy (SEM), and X-ray diffraction. A finite element analysis, a biaxial flexure test, as well as fractographic and Weibull analyses, were performed. The strengths of the disks were statistically different for the treatment factor, and the principal stresses seemed to be concentrated at the centre of the specimens, as predicted by the computer simulations. Ageing decreased the strengths for all groups and increased the Weibull modulus for the laser group with the 40 μm-width between two grooves. The sandblasting group presented the highest monoclinic phase peak. Although the most significant strength was found within the sandblasting group, the phase transformation was favourable to the laser groups. The Weibull modulus was higher for the laser group with the 60 μm-width between two grooves, confirming the highest homogeneity of its failure distribution. Regardless of the surface treatment, strength was decreased with ageing in all groups. The femtosecond Ti:Sa ultra-short pulse laser irradiation can be suggested as an alternative to the gold standard sandblasting in long-term Y-TZP zirconia rehabilitations, such as crowns and veneers.     

How to Prevent Flow Failures in Tailings Dams

Based on research carried out at 67 tailings dams in Spain: (1) tailings dams contain alternating sedimentary layers with contractive and dilative geomechanical behaviours; (2) tailings saturate quickly but drain more than 10 times slower due to the high-suction capacity of the porous sediments (2–300 MPa); and (3) over the long-term, a stationary flow regime is attained within a tailings basin. Four temporal and spatial conditions must all be present for a tailing dams flow failure to occur: (1) the tailings must experience contractive behaviour; (2) the tailings must be fully saturated; (3) the effective stress due to static or dynamic load must approach zero; and (4) the shear stress must exceed the tailings residual shear stress. Our results also indicate that the degree of saturation (S_r) is the most influential factor controlling dam stability. The pore-pressure coefficient controls geotechnical stability: when it exceeds 0.5 (S_r = 0.7), the safety factor decreases dramatically. Therefore, controlling the degree of tailings saturation is instrumental to preventing dam failures, and can be achieved using a double drainage system, one for the unconsolidated foundation materials and another for the overlying tailings.