No abstract available

No abstract available

[en] Synthetic Cd_1-xZn_xTe or 'CZT' crystals are highly suitable for the room temperature-based spectroscopy of gamma radiation. Structural/morphological heterogeneities within CZT, such as secondary phases that are thought to consist of Te metal and have detrimental impacts on detector performance. In this study, we used electron and X-ray-based imaging techniques to examine heterogeneous properties of detector grade CZT. Using experimental analytical techniques rather than arbitrary theoretical definitions, our study identifies two dominant secondary phase morphologies. The first consists of numerous empty, 20 (micro) m wide, pyramidal bodies (tetrahedra) or 'negative' crystals with trace quantities of particulate residue that exist as 65 nm sized particles containing Si, Cd, Zn, and Te. The other consists of 20 (micro)m hexagonal-shaped bodies, which are composites of metallic Te layers that contain a teardrop-shaped core of amorphous and polycrystalline CdZnTe which finally surrounds an irregular-shaped void

[en] Electrocatalysis plays a central role in clean energy conversion, enabling a number of sustainable processes for future technologies. This review discusses design strategies for state-of-the-art heterogeneous electrocatalysts and associated materials for several different electrochemical transformations involving water, hydrogen, and oxygen, using theory as a means to rationalize catalyst performance. By examining the common principles that govern catalysis for different electrochemical reactions, we describe a systematic framework that clarifies trends in catalyzing these reactions, serving as a guide to new catalyst development while highlighting key gaps that need to be addressed. Here, we conclude by extending this framework to emerging clean energy reactions such as hydrogen peroxide production, carbon dioxide reduction, and nitrogen reduction, where the development of improved catalysts could allow for the sustainable production of a broad range of fuels and chemicals.

[en] The $46 million budget cut in the US magnetic fusion program introduced a new approach that abandons the race to build a working power reactor in favor of a long-term emphasis on science, technology, and international cooperation. Administration policies which favor private funding for demonstration projects and general concern over the deficit have changed the overall fusion policy, although there is some concern among research groups that the program will become unfocused without its detailed timetable. If this happens, they see the program becoming even more vulnerable to future budget cuts. 2 references

[en] A comprehensive treatment of the theory of superfluid helium-3 is presented in this book. This treatment also illustrates many of the principal themes of theoretical condensed matter physics over the past two decades. The generalized BCS (Barden-Cooper-Schrieffer) pairing theory and the experimental properties of superfluid helium-3 are treated in detail. Extensive treatment of broken symmetries and their relation to macroscopic order and of the closely related topics of superflow and texture, defects in the order parameter field, and the dynamics of the nuclear spins as probed by nuclear magnetic resonance is included. This book should serve as a valuable reference for anyone working on superfluid helium-3 or on the closely related topics of unconventional superconductivity in heavy-electron metals and superfluidity of neutron star interiors

[en] An average age of 9.41 million years was obtained from radioisotope (potassium-argon) age determinations of three glass concentrates of a tuff from the upper part of the marine Rionegrense at Punta Cracker in Golfo Nuevo, Argentina. This age correlates with the Tortonian marine stage of Europe and the Chasicoan Land Mammal Age of South America

[en] The news aspects of the apparent loss of 20lbs of fuel-grade U at the Erin, TN Nulcear Fuel Services plant are reviewed. It is pointed out that the plant has continually had problems with inventory control. Some reasons for this inbalance in U inventory - other than theft of the material - are cited. These reasons are that there are many places the U could be at the moment of sampling, such as caught in pipes or tanks, lost in scrap, floating around in the air, or a figment of a prior miscalculation. Bias of measurements is also cited as a possible source of error. These possible sources of error, as well as insufficient security, are used as a basis for a recommendation that perhaps all handling of fuel-grade material be removed from NRC supervision and placed under the supervision of the Department of Energy who is more used to dealing with this type of problem. The problem of material accountability is seen as a serious problem if breeder reactors are used for commercial power and if fuel reprocessing is done by commercial firms

[en] A comparison of the size of polar coronal holes with the cosmic-ray intensity observed during the most recent sunspot cycle shows close correspondence. This lends support to recent suggestions that the well-known sunspot - cycle modulation of cosmic rays is a three-dimensional effect, probably related to the global character of the interplanetary magnetic field

[en] An unusual carbon-rich material found in the Abee meteorite is highly enriched in volatile elements, by factors of 10⁴ relative to the case for nonvolatile elements. Volatile-rich material of this type might form in the solar nebula toward the end of accretion, when small amounts of residual dust acquire all the uncondensed volatile elements. The mercury enrichment factor of 8500 could explain the paradox of the excess abundance of this element in meteorites