Some reactive processing aspects of high-temperature aluminides Nb3Al and RuAl

In the present investigation elemental powder mixtures with nominal composition of Nb-25at. % Al and Ru-50at.% Al corresponding to Nb₃Al and RuAl intermetallic phases were prepared. Green compacts from these mixtures were reactive sintered in vacuum or hot isostatically pressed after being encapsulated and reacted in quartz capsules. In the absence of pressure, reactive sintering at temperatures up to 1800 °C did not lead to densification, and swelling effects were observed. Reactions of formation of Nb₃Al and RuAl were found to take place at different temperature regions characteristic for each aluminide system, with clear dependence of the reaction temperature on the heating rate of the powder mixtures. Dilatometry studies showed that swelling occurred instantaneously at temperatures corresponding to the reaction temperature and led to a volume increase of about 25% and 42% for Nb₃Al and RuAl, respectively. The activation energy for the reactions was estimated from the differential thermal analysis. Similar data for the NiAl intermetallic phase were also obtained for comparison. The densification behavior and the phase composition of the reaction products were investigated and correlated with the heating rate, the mutual solubility of the reactants, and the amount of liquid phase available during the reaction.     

Database management and design

The use of a central repository for data and a database management system that enables programs to share data more efficiently and ensures the consistency of the data across the system is discussed. Relational databases, which represent both entities and relationships using tables, are described. It is shown that by proper design of the relational tables, the redundancy and wasted space of many ad hoc databases can be eliminated. Data are retrieved from a relational database through the use of a procedural query language. The leading query language for relational databases, the Structured Query Language (SQL), is examined     

A multicenter evaluation of a new continuous cardiac output pulmonary artery catheter system

OBJECTIVE: To validate a new system of continuous cardiac output monitoring. DESIGN: Multicenter, prospective, nonrandomized clinical study. SETTING: Four university hospitals. PATIENTS: Forty-seven adult intensive care unit patients. INTERVENTIONS: Pulmonary artery catheterization. MEASUREMENTS AND MAIN RESULTS: Continuous and bolus cardiac output measurements were obtained over 72 hrs. The 327 continuous cardiac output measurements compared favorably with bolus cardiac output measurements (bias = 0.12 L/min, precision = +/-0.84). The continuous cardiac measurement was not adversely affected by temperatures of <37 degrees C or >38 degrees C, high (>7.5 L/min) or low (<4.5 L/min) cardiac output values, or duration (72 hrs) of the study. CONCLUSIONS: This continuous cardiac output system provides a reliable estimate of cardiac output for clinical use if applied in conditions similar to this study. The combination of a continuous measure of cardiac output with other continuous physiologic monitoring (arterial and mixed venous oxygen saturation, oxygen consumption, etc.) may provide important information that no single parameter could achieve.     

Adjustment, mental health opinions, and proficiency of child care personnel.

Intercorrelated MMPI validity and K-corrected diagnostic scale scores, responses to a mental health opinion questionnaire, biographical data, and job performance ratings of 52 child care personnel. There were significant (p     

Mechanical fabrication of reactive metal laminate powders

A new mechanical method for creating reactive laminate powders has been developed using a two-step process; in the first step bulk reactive materials are created by cold-rolling stacks of alternating sheets of nickel and aluminum into foils with bilayer thicknesses ranging from 2.9 to 1.8 μm. This step establishes the average reactant spacing and, hence, the reactivity of the material. In the second step the rolled foils are then ground into laminate powders and sieved based on their diameters, which range from 850 to 53 μm. Our processing methodology allows the particle size and the reactant spacing to be varied independently. Powders made by this method have heat releases within a differential scanning calorimeter (DSC) that vary with the average reactant spacing, similar to rolled and sputter deposited foils. However, the measured heats also vary with the average diameter of the powders, as smaller particles show a systematic decrease in heat. Furthermore, this effect is magnified for the powders with the coarsest microstructure, as they show the largest drop in DSC heat release. The physical densities also vary as a function of particle size. The powders with the largest average bilayer thickness become Ni-rich at the smallest particle sizes, powders with the next finest average bilayer thickness become Al-rich, and powders with the smallest average bilayer thickness show little variation. We attribute the particle size dependence of the DSC heats to small powders being broken from regions of the original rolled foils that contain a high volume fraction of Ni-rich and Al-rich bilayers. These microstructural and chemical variations alter the exothermic reactions that are seen during slow heating in a DSC, as well as the heats of reaction that are measured in the DSC as a function of powder size. We support this hypothesis of non-random breakup during grinding by simulating bimodal distributions of bilayer chemistry within powders and modeling their densities and heats of reaction. The simulations are compared with measured values. Finally, we normalize the effects of particle size and bilayer thickness by plotting the measured DSC heats of reaction versus the number of bilayers per particle; the values merge toward one curve, with the largest decrease in heat occurring when there are fewer than 150 bilayers in each particle. This ratio proves useful when selecting particles for particular applications.     

Demonstration of protein tyrosine phosphatase activity in the second of two homologous domains of CD45

It has been reported that alteration of deletion of critical residues within one of the two homologous protein tyrosine phosphatase (PTPase)-like domains of CD45 completely abolishes all activity, suggesting that only the more N-terminal domain is catalytically active. However, we now demonstrate, by two independent techniques, that the second (C-terminal) domain is also a viable phosphatase. Limited proteolysis by endoproteinase Lys-C or trypsin increased the phosphatase activity toward reduced, carboxymethylated, and maleylated lysozyme approximately 8-fold. A 50-kDa fragment, isolated by ion exchange chromatography, was found to be responsible for this activity. N-terminal sequencing revealed that this fragment includes less than half of the first phosphatase domain and most, if not all, of the second. In a second experiment, 109 residues, including the presumed catalytic region, were removed from domain I by site-directed mutagenesis. Expression of this construct in a mammalian cell line resulted in increased PTPase activity over nontransfected control cells. Isolation of the recombinant CD45 by immunoprecipitation and immunoaffinity chromatography revealed that it had phosphatase activity. Both of these experimental approaches demonstrate that the second conserved PTPase domain of CD45 is a functioning PTPase, but that external regulation may be required to express its activity in the context of the native molecule.     

The hyperkinetic child: Effect of incentives on the speed of rapid tapping.

Studied 36 hyperkinetic and 36 control boys, ages 8-11, on a rapid-tapping task. Ss were divided into 3 incentive groups: 1 allowed to respond freely (U), 1 encouraged to tap rapidly (S), and 1 given pennies for increasing their tapping rate (R). As expected, the R and S groups tapped more rapidly than the U groups. When analyzed separately, no significant incentive group differences were found for hyperkinetics. The moderately fast tapping of the hyperkinetics, regardless of group, resulted in U hyperkinetics tapping more rapidly than U controls, but when incentive was introduced (S and R groups), controls were able to tap faster than the hyperkinetics. This inability of the hyperkinetics to adaptively adjust to the changing incentive conditions is suggested to be a function of defects in brain structures regulating arousal and concentration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ozone Assisted Biological Treatment Of Industrial Wastewaters Containing Biorefractory Compound

Ozone pretreatment studies of organic compounds that are difficult to biodegrade were conducted to evaluate the effects of ozonation on biodegradability of these compounds. Initial testing was conducted in batch activated sludge experiments with and without preozonation to evaluate the impacts of ozonation on the ultimate BOD/COD and ultimate BOD/TOC ratios of these compounds. Experimental results indicated wastewater preozonation to be an effective pretreatment step for some compounds, ineffective for other compounds and detrimental to biological treatment of still other compounds. These same compounds were then investigated in continuous flow, complete–mix activated sludge systems. Complete material balances, including influent, effluent, waste sludge and off–gas specific compound analyses, were conducted so that the actual fate of the compound could be determined. Removal mechanisms of the ozonated or unozonated compound were then determined to be biodegradation, stripping, or sorption to the biomass. Three compounds were investigated: acrylonitrile, 2,4 dinitrophenol, and 1,2 dichloropropane.     

Interventions for intimate partner violence: Review and implications for evidence-based practice.

The objective of this article was to survey available intimate partner violence (IPV) treatment studies with (a) randomized case assignment, and (b) at least 20 participants per group. Studies were classified into 4 categories according to primary treatment focus: perpetrator, victim, couples, or child-witness interventions. The results suggest that extant interventions have limited effect on repeat violence, with most treatments reporting minimal benefit above arrest alone. There is a lack of research evidence for the effectiveness of the most common treatments provided for victims and perpetrators of IPV, including the Duluth model for perpetrators and shelter–advocacy approaches for victims. Rates of recidivism in most perpetrator- and partner-focused treatments are approximately 30% within 6 months, regardless of intervention strategy used. Couples treatment approaches that simultaneously address problems with substance abuse and aggression yield the lowest recidivism rates, and manualized child trauma treatments are effective in reducing child symptoms secondary to IPV. This review shows the benefit of integrating empirically validated substance abuse and trauma treatments into IPV interventions and highlights the need for more work in this area. (PsycINFO Database Record (c) 2010 APA, all rights reserved)