Photoelastic Measurement of High Stress Profiles in Ion-Exchanged Glass

Photoelastic fringes were directly measured to fully characterize high magnitude, steep compressive stress gradients in an ion-exchanged glass, trade named Ion-Armor™. Initially, using a thick (9.9 mm) rectangular bar and circular polariscope arrangement the overall residual stress profile in a bulk specimen was determined. However, due to the relatively large thickness of the specimen, the high density of fringes (steep stress gradient) close to the edge of the specimen became too diffused to allow an accurate count of fringe order. A thinner (0.71 mm) specimen was then used along with a polarizing light microscope to enhance the fringe contrast. This arrangement yielded approximately four isochromatic fringes, representing a maximum surface compressive stress of 984 MPa, which rapidly decreased to ~300 MPa within 25 μm depth from the strengthened surface. Also, the case-depth of the ion-exchange process was found to be 0.8 mm. Thus, the technique was able to directly capture the extremely high residual compressive stresses generated in an ion-exchanged glass. The current technique utilized for residual stress measurement is more objective and straightforward to implement than what is specified in ASTM standard C-1422, particularly for those specimens having steep stress gradients just below the strengthened surface.     

Personality and substance dependence symptoms: Modeling substance-specific traits.

Personality traits related to neuroticism and disinhibition have been consistently associated with substance use disorders (SUDs). It is unclear, however, whether different personality traits predict distinct forms of substance dependence. Additionally, it is unclear whether personality traits continue to predict alcohol, drug, and tobacco dependence after controlling for comorbid antisociality and other SUDs. The current study addresses these questions by characterizing relations between personality traits and substance dependence symptoms in a longitudinal sample of 3,720 college students. Results revealed that antisociality and certain core personality traits predicted multiple types of substance pathology. In addition, several personality traits were differentially associated with alcohol, drug, and tobacco symptomatology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of human activities on benthic macroinvertebrate community composition and water quality in the upper catchment of the Mara River Basin,Kenya

Land‐use changes in the upper reaches of the Mara River Basin have modified their biophysical and hydrological processes, resulting in water quality degradation in streams. This study was conducted to investigate the effects of human activities on water quality and macroinvertebrates along the Nyangores River, one of the main tributaries of the Mara River, Kenya. Seven sampling sites were chosen to correspond to the loss of riparian cover, livestock watering and human activities (e.g. laundry washing, bathing, cultivation, wastewater inputs, dumping of solid wastes from urban areas and settlements along the river). Physical–chemical variables and water samples for nutrient analyses were collected monthly from February to July 2012. Benthic macroinvertebrates also were collected at the same sites as for the water quality samples. Two‐way analysis of variance tested the significant differences for each variable among the sites. Similarity percentages (SIMPER) analysis was used to identify the key taxa contributing to differences between minimally disturbed and most disturbed conditions in the study area. The results indicated increased nutrient concentrations in agricultural and settlement areas. Significant (P < 0.05) spatial–temporal variations in water quality variables were observed. A total of 42 macroinvertebrate genera were encountered, with Ephemeroptera, Plecoptera and Trichoptera orders dominating the minimally disturbed areas, and Diptera dominating the disturbed areas receiving point and no‐point solid and liquid wastes, including nutrients, from urban areas and settlements. Canonical correspondence analysis (CCA) revealed significant relationships between macroinvertebrate communities and measured physicochemical variables. The results of this study indicate the need for protection of riparian zones and treatment of sewerage wastes before their release into waterways. The dumping of solid wastes near streams and rivers also is discouraged, to maintain the quality of surface waters and aquatic organisms.     

Analysis of the human immune response to vaccinia by use of a novel protein microarray suggests that antibodies recognize less than 10% of the total viral proteome

Control of smallpox by mass vaccination was one of the most effective public health measures ever employed for eradicating a devastating infectious disease. However, new methods are needed for monitoring smallpox immunity within current vulnerable populations, and for the development of replacement vaccines for use by immunocompromized or low-responding individuals. As a measure for achieving this goal, we developed a protein microarray of the vaccinia virus proteome by using high-throughput baculovirus expression and purification of individual elements. The array was validated with therapeutic-grade, human hyperimmune sera, and these data were compared to results obtained from individuals vaccinated against smallpox using Dryvax. A high level of reproducibility with a very low background were apparent in repetitive assays that confirmed previously reported antigens and identified new proteins that may be important for neutralizing viral infection. Our results suggest that proteins recognized by antibodies from all vaccinees constituted <10% of the total vaccinia proteome.     

Plasmonic and photonic scattering and near fields of nanoparticles

We theoretically compare the scattering and near field of nanoparticles from different types of materials, each characterized by specific optical properties that determine the interaction with light: metals with their free charge carriers giving rise to plasmon resonances, dielectrics showing zero absorption in wide wavelength ranges, and semiconductors combining the two beforehand mentioned properties plus a band gap. Our simulations are based on Mie theory and on full 3D calculations of Maxwell’s equations with the finite element method. Scattering and absorption cross sections, their division into the different order electric and magnetic modes, electromagnetic near field distributions around the nanoparticles at various wavelengths as well as angular distributions of the scattered light were investigated. The combined information from these calculations will give guidelines for choosing adequate nanoparticles when aiming at certain scattering properties. With a special focus on the integration into thin film solar cells, we will evaluate our results.     

Designing block copolymer architectures for targeted membrane performance

Using a combination of block copolymer self-assembly and non-solvent induced phase separation, isoporous ultrafiltration membranes were fabricated from four poly(isoprene-b-styrene-b-4-vinylpyridine) triblock terpolymers with similar block volume fractions but varying in total molar mass from 43 kg/mol to 115 kg/mol to systematically study the effect of polymer size on membrane structure. Small-angle X-ray scattering was used to probe terpolymer solution structure in the dope. All four triblocks displayed solution scattering patterns consistent with a body-centered cubic morphology. After membrane formation, structures were characterized using a combination of scanning electron microscopy and filtration performance tests. Membrane pore densities that ranged from 4.53 × 10¹⁴ to 1.48 × 10¹⁵ pores/m² were observed, which are the highest pore densities yet reported for membranes using self-assembly and non-solvent induced phase separation. Hydraulic permeabilities ranging from 24 to 850 L m⁻² h⁻¹ bar⁻¹ and pore diameters ranging from 7 to 36 nm were determined from permeation and rejection experiments. Both the hydraulic permeability and pore size increased with increasing molar mass of the parent terpolymer. The combination of polymer characterization and membrane transport tests described here demonstrates the ability to rationally design macromolecular structures to target specific performance characteristics in block copolymer derived ultrafiltration membranes.     

Pyrolysis of model compounds on spent oil shales, minerals and charcoal: Implications for shale oil composition

Aliphatic compounds (alkanes, alkenes, alkanoic acids, ketones, alcohols and amines) were passed through beds of spent oil shales (Condor brown, Condor carbonaceous, Julia Creek), minerals (quartz, calcite, K-feldspar, pyrite, kaolinite) and charcoal at temperatures of 300–600 °C and the products were analysed by g.c.m.s. All the materials catalysed isomerization, aromatization and cracking to varying degrees: non-clay minerals < kaolinite ≈ spent oil shales < charcoal. Products included branched alkanes, isomeric alkenes, nitriles, ketones and alkyl-substituted benzenes, naphthalenes, pyridines, phenols, thiophenes and pyrroles. These compounds occur in shale oils and may be derived from secondary reactions of aliphatic products arising from kerogen cracking.     

Postmodern sandplay: An introduction for play therapists.

In this article we apply postmodern insights to sandplay therapy. In doing so, we seek to move sandplay therapy from its traditional base of an endeavor at problem solving: a therapeutic method to aid one's diagnosis and address concerns over functioning. Rather, we offer an approach to sandplay therapy from a base of postmodern thought. As has been done in the field of family therapy with solution-building therapy (De Jong & Berg, 2002) and narrative therapy (White, 2007), postmodern insights transform this therapeutic method into a narrative endeavor concerned with the articulation of identity as the means to foster change in the client. Sandplay offers a safe and secure site where the articulation of this new, empowered identity begins to get crafted. (PsycINFO Database Record (c) 2011 APA, all rights reserved)