UV vapor generation for determination of selenium by heated quartz tube atomic absorption spectrometry

A new vapor generation technique utilizing UV irradiation coupled with atomic absorption for the determination of selenium in aqueous solutions is described. In the presence of low molecular weight organic acid solutions, inorganic selenium(IV) is converted by UV irradiation to volatile selenium species, which are then rapidly transported to a heated quartz tube atomizer for detection by atomic absorption spectrometry. Optimum conditions for photochemical vapor generation and interferences from concomitant elements were investigated. Identification of the volatile products using cryotrapping GC/MS analysis revealed that inorganic selenium(IV) is converted to volatile selenium hydride, selenium carbonyl, dimethyl selenide, and diethyl selenide in the presence of formic, acetic, propionic, and malonic acids, respectively. In acetic acid solution, the efficiency of generation was estimated to be 50 +/- 10%. No interference from Ni(2+) and Co(2+) at concentrations of 500 and 100 mg L(-)(1), respectively, was evident. A detection limit of 2.5 microg L(-)(1) and a relative sensitivity of 1.2 microg L(-)(1) (1% absorption) with a precision of 1.2% (RSD, n = 11) at 50 microg L(-)(1) were obtained.     

The role of the self-concept and the social context in determining the behavior of power holders: Self-construal in intergroup versus dyadic dispute resolution negotiations.

In this work, the authors explored how a person's view of himself or herself might determine his or her use of power in a complex dispute resolution negotiation. In 3 studies of asymmetric power in negotiations, the authors demonstrated that the impact of power on motivation and behavior is moderated by both a person's self-view and the social context. In Study 1, the results revealed that in a one-on-one dispute, powerful individuals primed to hold an interdependent (as opposed to independent) self-construal are more generous in resolving their disputes with low-powered opponents. Study 2 replicated this finding but revealed a different pattern in intergroup disputes, in which powerful interdependent teams of negotiators are actually less generous than are independent teams. Study 3 provided a conceptual replication of Study 2, with the use of chronic measures of self-construal and self-reported measures of behavior. Results suggest that an interdependent self-construal may lead to a more benevolent use of power in dyadic conflicts but more exploitive uses of power in intergroup conflicts. Implications for the understanding of power and self-construal are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Active Integrated Antenna Design Using a Contact-Less, Proximity Coupled, Differentially Fed Technique

A novel contact-less, differential feeding technique suitable for integrated active antenna design is demonstrated. This technique utilizes an odd mode signal to generate fringing fields on either side of a microstrip gap under the antenna. This allows electromagnetic energy to be efficiently coupled from the transmission lines to the radiating antenna. In a balanced integrated antenna amplifier configuration, the proposed non-contact feeding method removes the need for any balun or power combining network. Hence in theory, a compact RF front-end design with lower losses can be realized. This feeding method has been successfully applied to the design of simple passive microstrip patch antennas and active integrated antennas (AIA). Simulated and measured results are also included to validate the proposed feeding concept and antenna designs. The performance of the proposed differential feeding technique on a simple microstrip patch antenna has been systematically studied. The study suggests that the proposed proximity method is broadband in nature, allowing antennas operating at different resonant frequencies to be swapped without the need to change the feed dimensions and without degrading the matching performance     

Porcelain Faucet Handle Failure Analysis

A porcelain faucet handle failed after years of use in a residential rental property. Determining the cause of failure was hampered by the fact that the failed handle was no longer available. The analysis included mechanical testing of exemplar faucet handles to measure the reasonable forces that could be applied by hand and the forces necessary to cause failure. Interface geometry between the porcelain handle and the interior metal nut was a factor. Finite Element Analysis facilitated the study. Results showed that if the faucet handle had sustained damage during a gasket repair, then the failure could be accounted for.     

Consumers’ adoption of information services

This paper reports on a design science research study that seeks to investigate how information service components affect consumers’ potential adoption of such services. More specifically, the paper develops a conceptual model that uses the theory of organizational information services (TOIS) and the unified theory of acceptance and use of technology (UTAUT) as a basis. The results indicate that individual constructs can be linked to service components. In turn, this result can potentially be instrumental in progress toward a deeper understanding of consumers’ adoption of information services and how this affects the development of such services and systems that support them.     

Analysis of the relationship between spatial pattern and spectral detectability of areas burned in southern Africa using satellite data

Fires in Africa affect atmospheric emissions and carbon sequestration, landscape patterns, and regional and global climatic conditions. Studies of these effects require accurate estimation of the extent of measurable fire events. The goal of this study was to assess the influence of burned area spatial patterns on the spectral detectability of burned areas. Six Landsat‐7 ETM+ images from the southern Africa were used for burned area mapping and spatial pattern analysis, while contemporaneous MODIS 500 m spatial resolution images were used to measure the spectral detectability of burned areas. Using a 15 by 15 km sample quadrats analysis, we showed that above a burned area proportion threshold of approximately 0.5 the spectral detectability of burned areas increase due to the decrease in the number of mixed pixels. This was spatially related to the coalescence of burned patches and the decrease in the total burned area perimeter. Simple burned area shapes were found at the Botswana site, where the absence of tree cover and the presence of bright surfaces (soil and dry grass) enhanced the spectral contrast of the burned surfaces, thus enabling better estimates of burned area extent. At the Zambia and Congo sites, landscape fragmentation due to human activity and the presence of a tree vegetation layer, respectively, contribute to the presence of small burned area patches, which may remain undetectable using moderate spatial resolution satellite imagery, leading to less accurate burned area extent estimates.     

A Functional Explanation for Patterns of Norditerpenoid Alkaloid Levels in Tall Larkspur (Delphinium barbeyi)

Concentrations of norditerpenoid alkaloids vary among larkspur (Delphinium) species, locations, and years, but environmental stresses seem to have little effect on alkaloid levels. There is a need for a functional hypothesis of alkaloid synthesis and metabolism to explain the observed trends in concentration and to predict the toxicity of larkspur populations. This study was replicated at two locations over two years in the mountains of central Utah. Ten tall larkspur (D. barbeyi) plants were marked at each location, and a single stalk was harvested from each plant at weekly intervals throughout the growing season. Concentrations of toxic and total alkaloids were measured by Fourier-transformed infrared spectroscopy (FTIR), and alkaloid pools were calculated by multiplying the alkaloid concentration by the dry weight of the plant to determine the amount of alkaloids in the stalk. Alkaloid pools in the stalks increased for the first three weeks, leveled off, and then declined to low levels as the plants began to senesce. Concentrations of alkaloids declined through the season, as the alkaloids were diluted in the increasing biomass as the plants grew. These patterns will be used to predict potential toxicity of larkspur populations.     

The membrane protein alkaline phosphatase is delivered to the vacuole by a route that is distinct from the VPS-dependent pathway

Membrane trafficking intermediates involved in the transport of proteins between the TGN and the lysosome-like vacuole in the yeast Saccharomyces cerevisiae can be accumulated in various vps mutants. Loss of function of Vps45p, an Sec1p-like protein required for the fusion of Golgi-derived transport vesicles with the prevacuolar/endosomal compartment (PVC), results in an accumulation of post-Golgi transport vesicles. Similarly, loss of VPS27 function results in an accumulation of the PVC since this gene is required for traffic out of this compartment. The vacuolar ATPase subunit Vph1p transits to the vacuole in the Golgi-derived transport vesicles, as defined by mutations in VPS45, and through the PVC, as defined by mutations in VPS27. In this study we demonstrate that, whereas VPS45 and VPS27 are required for the vacuolar delivery of several membrane proteins, the vacuolar membrane protein alkaline phosphatase (ALP) reaches its final destination without the function of these two genes. Using a series of ALP derivatives, we find that the information to specify the entry of ALP into this alternative pathway to the vacuole is contained within its cytosolic tail, in the 13 residues adjacent to the transmembrane domain, and loss of this sorting determinant results in a protein that follows the VPS-dependent pathway to the vacuole. Using a combination of immunofluorescence localization and pulse/chase immunoprecipitation analysis, we demonstrate that, in addition to ALP, the vacuolar syntaxin Vam3p also follows this VPS45/27-independent pathway to the vacuole. In addition, the function of Vam3p is required for membrane traffic along the VPS-independent pathway.     

The use of coal liquefaction catalysts for coal/oil coprocessing and heavy oil upgrading

The catalytic hydrogenation of heavy oil and mixed coal-heavy oil (coprocessing) systems has been the focus of a recent study at the Federal Energy Technology Center (FETC). The intent of this effort was to extend the use of coal liquefaction technologies to heavy oil upgrading and coprocessing systems. Specifically, new dispersed molybdenum-based catalysts developed at FETC and a novel silica-doped hydrous titanium oxide (HTO : Si)-supported NiMo catalyst developed at Sandia National Laboratories (SNL) were tested in these systems. The results indicate the potential of coal liquefaction catalysts for use in coprocessing and heavy oil upgrading. High conversions of coal–oil mixtures were observed with dispersed catalyst loadings as low as 100 ppm Mo. Similar results were observed in heavy oil systems. Also, the novel NiMo/HTO : Si catalyst was at least as effective as commercially-available supported catalysts (e.g. Amocat 1C) for conversion of high boiling point material to distillable products and aromatics removal.