Inorganic Halide Perovskitoid TlPbI3 for Ionizing Radiation Detection

Room temperature semiconductor detector (RTSD) materials for γ-ray and X-ray radiation are in great demand for the nonproliferation of nuclear materials as well as for biomedical imaging applications. Halide perovskites have attracted great attention as emerging and promising RTSD materials. In this contribution, the material synthesis, purification, crystal growth, crystal structure, photoluminescence properties, ionizing radiation detection performance, and electronic structure of the inorganic halide perovskitoid compound TlPbI₃ are reported on. This compound crystallizes in the ABX₃ non-perovskite crystal structure with a high density of d = 6.488 g·cm^–3, has a wide bandgap of 2.25 eV, and melts congruently at a low temperature of 360 °C without phase transitions, which allows for facile growth of high quality crystals with few thermally-activated defects. High-quality TlPbI₃ single crystals of centimeter-size are grown using the vertical Bridgman method using purified raw materials. A high electrical resistivity of ≈10¹² Ω·cm is readily obtainable, and detectors made of TlPbI₃ single crystals are highly photoresponsive to Ag K_α X-rays (22.4 keV), and detects 122 keV γ-rays from ⁵⁷Co radiation source. The electron mobility-lifetime product µ_eτ_e was estimated at 1.8 × 10^–5 cm²·V^–1. A high relative static dielectric constant of 35.0 indicates strong capability in screening carrier scattering and charged defects in TlPbI₃.     

Cottonseed oil pigments: Fractionation by means of molecular sieves,countercurrent distribution,and low-temperature crystallization

Crude cottonseed oils were shown to have spectra of two types, those exhibiting a single maximum at about 360 mμ and those exhibiting a double maxima at about 375 and 400 mμ. Gossypol and cottonseed oil pigments which absorb below about 375 mμ are trapped by molecular sieve No. 13X, appear in the hydrophilic phase in countercurrent distribution of the oil between 95% ethanol and isooctane, and are found in the liquid fraction on crystallization of oil from acetone at −63°C. Those pigments not admitted by molecular sieve No. 13X are found in the hydrophobic phase in countercurrent distribution and in the solid fraction from low-temperature crystallization. Only countercurrent distribution achieved separation of both types of pigments from the triglycerides. Insufficient quantities of pigments were isolated for any extensive characterization. Use of large-scale apparatus would appear to make it possible to separate the pigments for characterization and evaluation of their relation to the refining properties of oils. Presented at the Annual Meeting, American Oil Chemists' Society, Dallas, Tex., April 4–6, 1960. National Cottonseed Products Association Fellow. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Analytic theory of coherent cross-gain modulation in semiconductor travelling-wave amplifiers

Abstract

We report a simple analytic solution to the problem of cross amplitude-phase modulation in nonlinear two-wave mixing, under the approximation of constant saturating power. The results are applied to travelling-wave semiconductor laser amplifiers where the linewidth enhancement factor inevitably leads to amplitude-phase coupling and asymmetric energy transfer. Our solution is used to obtain the transmission gain of each beam, the spectral profile and the amplifier input-output characteristics. Limits are established as to the applicability of the analytic solution, by comparison with numerical solutions to the related full four-wave mixing problem.     

Primary aromatic amine migration from polyamide kitchen utensils: method development and product testing

A rapid and sensitive LC-MS/MS method for the identification, quantification and confirmation of six primary aromatic amines (PAAs) was developed and validated to ISO 17025:2005. From a literature survey, 57 frequently used PAA compounds were identified and subsequently reduced to six - aniline, 4,4'-MDA, 3,3'-DMB, 2,4-TDA, 2,6-TDA and o-T - based on results from migration studies on a range of utensils. Low LOQs of between 0.075 and 0.496 μg l(-1) were determined for the six analytes, thereby quantifying well below the legal limit of 10 μg kg(-1) total PAAs. Furthermore, low measurement uncertainties were calculated for the analytical method, in the range of 3.15-3.20%. Mean recoveries were between 98% and 102% and spanned over ±12% at 95% CI. Following the analysis of 84 black polyamide kitchen utensils, the migration of PAAs detected was significant and is therefore of concern. The six analytes identified, quantified and confirmed in this survey could be utilised as possible markers for the identification of PAA migration, thereby improving the time and cost-efficiency of food control laboratories.     

An Interactive Computer Peripheral to Measure the Electromyographic Silent Period

A device to provide automated measurement of the electromyographic silent period with real time capability utilizing a voltagetime window is described. This device is being used in the clinical dental diagnosis and treatment of functional disorders of the masticatory system. The design, performance, utilization, and other applications of this device are discussed.     

Anger of African American women in the south

In this existential-phenomenological investigation middle-class African American women (n = 9) in the Southern United States were interviewed about their experience of anger in daily life. The purpose of the study was to examine what African American women's anger is about, what it means, and how it is experienced. Transcribed interviews were analyzed using a hermeneutic process. The thematic structure of African American women's anger comprises three main elements that stand out as figural: power, control, and respect. These figural elements can be understood only when seen against the ground of a racist Southern culture that produces pervasive mistrust. These findings are of importance to clinicians, who cannot deliver culturally competent interventions to African American female clients without a clear understanding of the complexity and meaning of their anger experience.     

Water chemistry and processing effects on the corrosion degradation of copper tubing in cooling water systems

Specimens of copper tubing from an industrial scale chiller were subjected to a complete corrosion failure analysis. Nondestructive inspection of the tubing indicated substantial corrosion damage and provided the impetus for the corrosion analysis. By application of the typical methods encountered in metallurgical failure investigations, as well as additional chemical analysis techniques, the most probable cause of failure was identified to be a change in the water chemistry during the service life of the tubes. Additional items that may have contributed to the failure include the geometric design of the tube and the post-manufacture cleaning process prior to service. Recommendations were made regarding water treatment and the requirements for any replacement tubes. In addition to discussion of the specific failure(s) investigated, notes regarding the general procedures for corrosion failure analysis are also presented.     

Forming high temperature solder joints through liquid phase sintering of solder paste

Eutectic lead-tin has been the solder of choice throughout the history of the electronics industry. Alternatives to this material are now being considered because of environmental concerns, as well as the strength and temperature limitations of eutectic lead-tin. Identifying and using these alternative materials poses significant challenges, many of which we believe can be addressed if one forms solder joints through liquid phase enhanced sintering. First, most alternative solder materials have significantly higher melting temperatures (than eutectic lead-tin), and their use would require the replacement of much of the manufacturing infrastructure. In this work joints with shear stresses approaching that of eutectic lead-tin solder were formed by sintering a eutectic tin-sliver solder paste (T_m=221°C) doped with 3 v/o eutectic Sn-Bi powder at 210°C for 30 min. Second, to date the industry has limited its consideration to eutectic or near-eutectic alloys because of the concern of forming cold solder joints. In this work joints have been prepared by sintering solder pastes with a wide thermal range at temperatures just above the solidus, where a small amount of liquid will form and therefore enhance the rate of sintering, which have shear strengths of 6 MPa or higher. These findings indicate that it may be worthwhile to investigate developing a sinterable solder paste, which can be used to prepare surface mount assemblies.     

Identifying leadership potential in future international executives: Developing a concept.

Develops a conceptual framework for assessing international executive (IE) potential by examining the ability to learn from experience, using the published research and interviews with experienced IEs. If the skills of an IE are developed over time rather than innate, such end-state characteristics might not be present. In this context, potential is defined as the ability to take advantage of the developmental experiences that will be offered. The attributes of early identification in this framework consist of curiosity about how people and things work, accepting responsibility for learning and change, seeking and using feedback, a sense of adventure, readiness/hardiness, a bias toward action, respecting differences, and consistent growth. A framework for the early identification of IEs must have 3 components: individual attributes and skills, context, and time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)