Preparation and X-ray characterization of CsAlSiO4

A systematic study of the preparation of CsAlSiO₄ using various cesium oxide, alumina, and silica sources and a typical set of firing conditions was performed. The objective was to determine effective methods of preparing phase-pure CsAlSiO₄. The reaction of Cs₂CO₃ with metakaolin at 600°C (decomposition and calcining), 850°C (prefiring) and 1050°C (crystallization) produced the only phase-pure CsAlSiO₄ obtained by these methods. None of the eighteen sets of starting materials yielded a phase-pure CsAlSiO₄ in the 1100°C and 1200°C firings. CsAlSiO₄ was determined to be isomorphous with RbAlSiO₄ as reported by Klaska and Jarchow (1). CsAlSiO₄ is orthorhombic with lattice parameters of $\text{a}{}_{\mathrm{<mtext>o</mtext>}}\text{= 8.907 (2)}\text{A}\text{?}\text{,}\text{b}{}_{\mathrm{o}}\text{= 9.435(1)}\text{A}\text{?}\text{,}\text{and}\text{c}{}_{\mathrm{<mtext>o</mtext>}}\text{= 5.435(1)}\text{A}\text{?}$. The space group is Pna2₁, with Z = 4. Single crystals of CsAlSiO₄ were grown hydrothermally from a lCs₂O:1Al₂O₃:2SiO₂ gel in a 3M CsOH solution. The reaction conditions were 770°C and 11, 700 psi. The crystal habit of CsAlSiO₄ is needle-like.     

Surface snow properties effect on millimeter-wave backscatter

The authors examine the relationship between 94-GHz backscatter from snow cover and the properties of the snow, using statistical analysis of observations made in West Germany in 1986. For terrain covered by dry snow, 94-GHz backscatter does not appear to depend significantly on any of the measured snow properties. Backscatter from wet snow is found to be sensitive to volumetric liquid water content, with the dependence inverse-exponential in form. Backscatter from wet snow is also found to depend on surface roughness, especially the cross-polarized return. Comparison of the 1986 data with similar data obtained in 1984 shows two major disagreements in the response of the vertical transmit vertical receive polarization backscattering coefficient to wet snow surface roughness, and the response of cross-polarized. The backscattering coefficient to snow surface wetness. The 1986 results are considered more reliable     

Sociability: Personality, social context, and physical setting.

Sociability, measured as amount of participation in a peer-group conversation, was examined as a function of traits (Personality Research Form), social context, and physical setting. Same-sex quartets of 84 13–17 yr old students discussed a topic selected by an outsider and a topic of the group's own choice. Amount of participation was expected to vary with personality (affiliation, defendence, and dominance), social context (level of acquaintance and friendship in the group), physical setting (seating arrangement), and interactions among these. Ss' participation rate was significantly related to affiliation, level of friendship, a person?×?setting interaction (seating arrangement?×?defendence) and a person?×?person interaction (affiliation?×?defendence). These relationships are discussed as they relate to a model of sociability and as they bear on the person?×?situation issue. Results demonstrate that sociability is a function of dispositions brought to a setting by an individual, the social context of that setting, and the physical arrangement of the setting. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hopelessness as a measure of suicidal intent in the depressed elderly.

Suicidal ideation in the elderly has been related to depression, changes in health, and anticipation of a limited future. The present study examined the Hopelessness Scale (HS) and its relation to these factors in a depressed geriatric population. A total of 120 elderly outpatients, who had applied to receive psychotherapy for depression, completed the HS, Beck Depression Inventory (BDI), health ratings, and the Schedule for Affective Disorder and Schizophrenia (SADS) at intake. The HS was found to be internally consistent, and a principal components analysis revealed three distinct factors that were related to hope, feelings of giving up, and future planning. The HS, BDI, and health ratings were predictive of suicidal ideation as measured by specific items in the SADS. The relation among suicidal ideation hopelessness, depression, and health perceptions for the depressed aged are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laboratory Evaluation of Crushed Glass–Dredged Material Blends

A comprehensive laboratory evaluation of blending 9.5?mm (3/8?in.) minus curbside-collected crushed glass (CG) with dredged material (DM) was conducted to evaluate their potential for beneficial use as fill materials for urban applications. Tests were performed on 100% CG (USCS classification SP) and 100% DM (OH) specimens and 20/80, 40/60, 50/50, 60/40, and 80/20 CG–DM blends (dry weight percent CG content reported first). The addition of 20% CG resulted in a 10–20 point (33–67%) reduction in wopt while increasing the dry density by approximately 1–3?kN/m3 for standard and modified levels of compaction, respectively. Simultaneously, the compressibility of the DM was reduced by approximately 50% and the hydraulic conductivity was reduced by ? order of magnitude. The addition of 20% CG significantly decreased the moisture content and significantly improved the workability of the 100% DM, where workability refers to the ease of handling, transport, placement, and compaction of the CG–DM blends (compared to 100% DM). CIū triaxial strength testing indicated effective friction angles of 34 and 37° for 100% DM and CG compacted to a minimum of 95% relative compaction by ASTM D1557, respectively. A peak effective friction angle of 39° occurred for the 60/40 and 80/20 CG–DM blends which were also 1 and 3 orders of magnitude more permeable than 100% DM, respectively. Related increases in cv resulted in decreased times required for consolidation. The range of properties obtainable by the CG–DM blends offers a versatility that allows for the design of fills that can be potentially optimized to meet multiple design parameters (e.g. strength, settlement, drainage, or higher CG or DM content).     

Effects of TiO2 Addition to LiNbO3 on the Cation Vacancy Content, Curie Temperature, and Lattice Constants

The defect model of Abrahams and Marsh is expanded to consider the addition of TiO₂ and other oxides to form solid solutions with both the stoichiometric and congruent compositions of LiNbO₃. It is shown that the Curie temperature (T_c) and the limits of solubility are determined by the cation vacancy content regardless of whether these are formed by Li deficiency or the addition or substitution of aliovalent ions. X-ray powder diffraction patterns indicate that the a-axis parameter decreases markedly with additions of TiO₂ while the c-axis parameter remains essentially unchanged. These results are compared with prior investigations, and the technological implications of this work to lightguide devices are described.