Ammonium phosphate slurry rheology and particle properties—The influence of Fe(III) and Al(III) impurities, solid concentration and degree of neutralization

Ammonium phosphate slurries are produced from impure phosphoric acid that contains Fe(III), Al(III) and Mg(II) ions. The insolubility of these metal ions and the onset of solid formation determined as a function of pH or mole ratio (MR) of ammonia to phosphoric acid were consistent with the trend for the pH of formation of the first hydrolysis product that decreases in the following order: Fe(III)<Al(III)<Mg(II). The hydrolysis products of Fe(III) formed at pH>2.0 or MR>0.5 initiate ammonium phosphate crystallization, reduce the size of particles formed and generate attractive interparticle forces. Similarly, the Al(III) hydrolysis products formed later at pH>2.6 MR>0.7), will also initiate further crystallization, adsorb on particles and produce attractive forces. The attractive forces and the high number concentration of particle—particle interactions are responsible for the increased viscosity and non-Newtonian flow behavior displayed at increasing Fe(III) and Al(III) concentration. Mg(II) ions are not hydrolyzed at MR<1.0 so its effect on rheology is negligible and its effect at MR<1.0 is also small as its concentration is much smaller than that of Fe(III) and Al(III) ions. The change in slurry viscosity with the degree of neutralization is also explained in terms of particle size distribution, solubility and solids concentration variations.     

Photoelectrochemical cells based on a novel porphyrin containing light harvesting conducting copolymer

A copolymer of anti-5,15-bis([2′,2″:5″,2″′-terthiophene]-3″-yl)-2,8,12,18-tetra-n-butyl-3,7,13,17-tetramethylporphyrin (1) with 2,2′:5′2″-terthiophene (2) was successfully electrosynthesised and was then characterised by cyclic voltammetry, UV-Vis spectroscopy, four-point probe conductivity measurement, and scanning electron microscopy. This novel light harvesting conducting copolymer was then incorporated into photoelectrochemical cells using a liquid electrolyte and tested for photovoltaic responses. The effect of zinc incorporation into the porphyrin cavity was also investigated, and the best device generated an open circuit voltage of 185 mV, short circuit current of 881 μA cm⁻² with a fill factor of 0.36 and energy conversion efficiency of 0.12% under a halogen white light intensity of 500 W m⁻².     

ModerateDrinking.Com and moderation management: Outcomes of a randomized clinical trial with non-dependent problem drinkers.

Objective: To evaluate the effectiveness of a web-based protocol, ModerateDrinking.com (MD; www.moderatedrinking.com) combined with use of the online resources of Moderation Management (MM; www.moderation.org) as opposed to the use of the online resources of MM alone. Method: We randomly assigned 80 problem drinkers to either the experimental or control group with follow-ups at 3, 6, and 12 months. Results: Seventy-five participants (94%) had outcome data at 1 or more follow-up points, and 59 participants (73%) were assessed at all 3 follow-ups. Comparing baseline measures to the average outcomes at follow-ups indicated a significant overall reduction in both groups in alcohol-related problems and consumption variables. Compared with the control group, the experimental group had better outcomes on percent days abstinent. There was an interaction between intensity of drinking at baseline and treatment in determining outcomes assessing drinking. Less heavy drinkers in the experimental group had better outcomes on log mean blood alcohol content (BAC) per drinking day compared with the control group. Heavier drinkers did not differentially benefit from the MD program on this measure. Mixed model analyses in general corroborated these outcomes. Conclusion: The outcome data provide partial evidence for the effectiveness of the MD web application combined with MM, compared with the effectiveness of the resources available online at MM by themselves. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Dielectrophoretically assembled particles: feasibility for optofluidic systems

This work presents the dielectrophoretic manipulation of sub-micron particles suspended in water and the investigation of their optical responses using a microfluidic system. The particles are made of silica and have different diameters of 600, 450, and 250 nm. Experiments show a very interesting feature of the curved microelectrodes, in which the particles are pushed toward or away from the microchannel centerline depending on their levitation heights, which is further analyzed by numerical simulations. In doing so, applying an AC signal of 12 V_p–p and 5 MHz across the microelectrodes along with a flow rate of 1 μl/min within the microchannel leads to the formation of a tunable band of particles along the centerline. Experiments show that the 250 nm particles guide the longitudinal light along the microchannel due to their small scattering. This arrangement is employed to study the feasibility of developing an optofluidic system, which can be potentially used for the formation of particles-core/liquid-cladding optical waveguides.     

Quality Indices for Aluminum Alloy Castings: A Critical Review

Several indices are available in the literature to assess the structural quality of cast Al alloys, especially Al-7 pct Si-Mg alloys that are based on tensile test results. Some of these indices, most notably the one developed by Drouzy et al., provide a number that necessarily does not have a physical meaning, whereas the others are a measure of what fraction of the expected tensile performance is achieved. These indices are analyzed in depth, their similarities and shortcomings are discussed in detail, and recommendations are made.     

Birth cohort differences in self-esteem, 1988–2008: A cross-temporal meta-analysis.

Three meta-analyses find increases over the generations in Rosenberg Self-Esteem scale (RSE) scores between 1988 and 2008 among American middle school (d = 0.78, n = 10,119), high school (d = 0.39, n = 16,669), and college students (d = 0.30, n = 28,918). The changes are consistent with an increasing emphasis on self-worth in American culture and, for high school students, with small increases in academic competence over time. College students' scores change only when the RSE is administered with a 4-point Likert scale with no midpoint. By 2008, a score of 40 (perfect self-esteem) was the modal response of college students, chosen by 18% of participants; 51% scored 35 or over. Given these shifts in responses, the possibility of revising the RSE is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex differences in impulsivity: A meta-analysis.

Men are overrepresented in socially problematic behaviors, such as aggression and criminal behavior, which have been linked to impulsivity. Our review of impulsivity is organized around the tripartite theoretical distinction between reward hypersensitivity, punishment hyposensitivity, and inadequate effortful control. Drawing on evolutionary, criminological, developmental, and personality theories, we predicted that sex differences would be most pronounced in risky activities with men demonstrating greater sensation seeking, greater reward sensitivity, and lower punishment sensitivity. We predicted a small female advantage in effortful control. We analyzed 741 effect sizes from 277 studies, including psychometric and behavioral measures. Women were consistently more punishment sensitive (d = ?0.33), but men did not show greater reward sensitivity (d = 0.01). Men showed significantly higher sensation seeking on questionnaire measures (d = 0.41) and on a behavioral risk-taking task (d = 0.36). Questionnaire measures of deficits in effortful control showed a very modest effect size in the male direction (d = 0.08). Sex differences were not found on delay discounting or executive function tasks. The results indicate a stronger sex difference in motivational rather than effortful or executive forms of behavior control. Specifically, they support evolutionary and biological theories of risk taking predicated on sex differences in punishment sensitivity. A clearer understanding of sex differences in impulsivity depends upon recognizing important distinctions between sensation seeking and impulsivity, between executive and effortful forms of control, and between impulsivity as a deficit and as a trait. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development and validation of a measure of academic entitlement: Individual differences in students’ externalized responsibility and entitled expectations.

Four studies present the validation of a self-report scale capturing academic entitlement, which is defined as the tendency to possess an expectation of academic success without a sense of personal responsibility for achieving that success. The Academic Entitlement scale possesses a 2-factor structure (Study 1); 10 items measure students’ Externalized Responsibility for their academic success, and 5 items measure students’ self-serving Entitled Expectations about professors and course policies. In Study 2, the Externalized Responsibility subscale correlated positively with related measures of entitlement, grandiosity, and narcissism, and it was negatively related to self-esteem, personal control, need for cognition, agreeableness, and conscientiousness. In Study 3, participants rated various responses to academic situations selected by university instructors as highly inappropriate or highly appropriate. The Academic Entitlement scale predicted students’ ratings of the appropriateness of these student behaviors as well as the likelihood that they themselves would engage in these behaviors. In a laboratory setting, individuals with high Academic Entitlement scores evaluated the researcher more negatively than those with low Academic Entitlement scores (Study 4). Practical applications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative Local Atomic Displacements from Huang Scattering Normalized by Thermal Diffuse Scattering

The three-dimensional (3-D) pattern of atomic displacements at the core of a small defect or defect cluster embedded in a bulk crystal is possible to measure in principle, but difficult to obtain in practice, especially if quantitative displacements are desired. Here, it is demonstrated that a least-squares fit to the single-crystal X-ray Huang-scattering distribution surrounding an intense Bragg peak is a practical means of obtaining quantitative displacements when thermal diffuse scattering is used as an internal intensity standard. After fitting a model based on local Kanzaki forces embedded within an elastic continuum, the use of finite-defect and point-defect methods of computing and interpreting the pattern of local displacements are compared and contrasted. To make the analysis general with regard to both crystal symmetry and defect symmetry, numerical Fourier transforms are employed rather than pursuing analytical expressions for the displacements.