Carbonitride precipitation in niobium/vanadium microalloyed steels

A detailed study of carbonitride precipitation in niobium/vanadium microalloyed steels is presented. A thermodynamic model is developed to predict the austenite/carbonitride equilibrium in the Fe−Nb-V-C-N system, using published solubility data and the Hillert/Staffansson model for stoichiometric phases. The model can be used to estimate equilibrium austenite and carbonitride compositions, and the amounts of each phase, as a function of steel composition and temperature. The model also provides a method to estimate the carbonitride solution temperatures for different steel compositions. Actual carbonitride precipitation behavior in austenite is then examined in two experimental 0.03Nb steels containing 0.05V and 0.20V, respectively. Samples were solution treated, rolled at 954°C (20 pct or 50 pct), held isothermally for times up to 10,000 seconds at 843°C, 954°C, or 1066°C, and brine quenched. The process of carbonitride precipitation in deformed austenite is followed by analytical electron microscopy (AEM) of carbon extraction replicas. Precipitates are observed at prior-austenite grain boundaries, and also within the grains (presumably at substructure introduced by the rolling deformation). Analysis of the grain-boundary and matrix precipitate compositions by AEM indicates that the grain-boundary precipitates are consistently richer in vanadium than the matrix precipitates, although compositional trends with holding time and temperature are similar for the two types of precipitates. The compositions of both the grain-boundary and matrix precipitates are not significantly influenced by the rolling reduction or the holding time at temperature. As predicted by the thermodynamic model, the precipitates become more vanadium-rich as the vanadium level in the steel is increased and as the temperature is reduced. The agreement between the measured and predicted precipitate compositions is quite good for the grain-boundary precipitates, although the matrix precipitates are consistently more niobium-rich than predicted by the model.     

Sorption of copper on lake monona sediments—effect of nta on copper release from sediments

A study has been conducted on the magnitude and mechanism of cupric binding to Lake Monona, Madison, Wisconsin, sediments. The binding capacity, which is the ability of the sediment to hold the copper, was found to be proportional to the carbonate content of the sediments. The addition of nitrilotriacetic acid to these sediments results in a release of iron and manganese and a reduction in the amount of copper present in solution.     

Effect of the Crystallization Process and Solid State Storage on the Physico-Chemical Properties of Scale-Up Lots of CI-936

N-(2,2-diphenylethyl)adenosine, designated as CI-936, is a novel, orally active antipsychotic agent. Depending on the manufacturing process, the drug substance exists in more than one crystalline form. Three lots of the drug were characterized by thermal analysis, scanning electron microscopy, X-ray diffraction, and dissolution. Two of these lots were found to be crystalline while the third was amorphous. The physical properties of the crystalline forms appear to change during storage under ambient conditions. The amorphous form, inspite of being in a high energy state, was not affected by storage. The absolute bioavailability of the amorphous form in dogs is more than 90%. In contrast, the other two crystalline lots demonstrated lower and unpredictable oral absorption profiles.     

Meaningful existence of finite element solutions to off-limit problems

Problems for which the variational principle of minimum potential energy breaks down, and are therefore formally unsuitable for a finite element analysis, are shown to possess, nevertheless, a useful discrete solution.     

Psychology and the moral imperative.

Examines the moral obligations of psychology. An inquiry into the main priorities of academic and professional psychology suggests that contributions to human welfare, its preeminent moral obligation, comes in third after guild issues and professional self-interest, and the pursuit of knowledge. In an effort to reassign moral philosophy a place of prominence and to broaden the ethical discourse of psychology, the authors use the term "moral imperative" (MI). The promotion of the MI entails the exploration of 3 fundamental questions. These concern the extent that the present social order promotes human welfare for everyone, the extent that psychology supports or challenges the present social order, and the contributions that psychology can make to the advent of the "good" society. The MI advances 4 human agency values: self-determination, distributive justice, collaborative and democratic participation, and relationality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Linkage of familial dilated cardiomyopathy with conduction defect and muscular dystrophy to chromosome 6q23

Inherited cardiomyopathies may arise from mutations in genes that are normally expressed in both heart and skeletal muscle and therefore may be accompanied by skeletal muscle weakness. Phenotypically, patients with familial dilated cardiomyopathy (FDC) show enlargement of all four chambers of the heart and develop symptoms of congestive heart failure. Inherited cardiomyopathies may also be accompanied by cardiac conduction-system defects that affect the atrioventricular node, resulting in bradycardia. Several different chromosomal regions have been linked with the development of autosomal dominant FDC, but the gene defects in these disorders remain unknown. We now characterize an autosomal dominant disorder involving dilated cardiomyopathy, cardiac conduction-system disease, and adult-onset limb-girdle muscular dystrophy (FDC, conduction disease, and myopathy [FDC-CDM]). Genetic linkage was used to exclude regions of the genome known to be linked to dilated cardiomyopathy and muscular dystrophy phenotypes and to confirm genetic heterogeneity of these disorders. A genomewide scan identified a region on the long arm of chromosome 6 that is significantly associated with the presence of myopathy (D6S262; maximum LOD score [Z(max)] 4.99 at maximum recombination fraction [theta(max)] .00), identifying FDC-CDM as a genetically distinct disease. Haplotype analysis refined the interval containing the genetic defect, to a 3-cM interval between D6S1705 and D6S1656. This haplotype analysis excludes a number of striated muscle-expressed genes present in this region, including laminin alpha2, laminin alpha4, triadin, and phospholamban.     

Out of reach

The disabled poor worry whether managed care will bring them into the medical mainstream or cast them adrift. That's why state Medicaid programs are approaching the task gingerly--if at all.     

Experimental determination of the equation of state of solid hydrogen and deuterium at high pressures

Isochores of solid hydrogen and deuterium have been measured for melting line pressures up to 2000 bar. These are corrected to correspond to para-H₂ and ortho-D₂. The 4.2 K isotherm of H₂ has been determined and compared to the extrapolated low-pressure isochore of Anderson and Swenson (AS). Deviations have led us to reanalyze the AS data. The 4.2 K isotherm and the isochores are used, with the aid of a Mie-Grüneisen analysis, to determine P-V-T data for these solids up to 25 kbar. An analysis is presented which enables a determination of P-V-T-C ₁ for all values of C ₁, the ortho-para concentration. Results, including the Debye temperature, Grüneisen constant, and bulk modulus, are presented both in tabulated and graphical form. We also present what we feel to be the best of the 4.2 K, zero-pressure molar volumes of disordered H₂ and D₂ as a function of C ₁. Our measurements show no indication of the premelting phase transition reported in recent Russian literature and a possible explanation is presented.Supported in part by the Stichting FOM.     

An equivalent circuit characterization of power MOSFET accounting for high field and high frequency effects

An equivalent circuit model for analyzing the AC characteristics of power VDMOS transistors is presented. The model accounts for high field and saturation effects. This is achieved by incorporating dependent voltage and current sources in the device model. Results are given for the AC characteristics of a POLYFET F2001 Power VDMOSFET rated with a drain current of 1.4A, power out of 2.5W at 1GHz. The linear, quasi-saturation and saturation regions of the IV characteristics are accounted for in the analysis. The small signal device parasitics are extracted through s-parameter methods. The s-parameter results were used to extract the frequency dependent parasitics including parasitic capacitances, inductances and transconductances.