Differential current switch logic: a low power DCVS logic family

Differential current switch logic (DCSL), a new logic family for implementing clocked CMOS circuits, has been developed. DCSL is in principle a clocked differential cascode voltage switch logic circuit (DCVS). The circuit topology outlines a generic method for reducing internal node swings in clocked DCVS logic circuits. In comparison to other forms of clocked DCVS, DCSL achieves better performance both in terms of power and speed by restricting internal voltage swings in the NMOS tree. DCSL circuits are capable of implementing high complexity high fan-in gates without compromising gate delay. Automatic lock-out of inputs on completion of evaluation is a novel feature of the circuit. Three forms of DCSL circuits have been developed with varying benefits in speed and power. SPICE simulations of circuits designed using the 1.2 μm MOSIS SCMOS process indicate a factor of two improvement in speed and power over comparable DCVS gates for moderate tree heights     

The effect of sodium sulfate on solidification/stabilization of a synthetic electroplating sludge in cementitious binders

The effect of sodium sulfate on the solidification/stabilization of a large quantity of a synthetic electroplating sludge in cementitious binders was s     

A local theory of heating in cross-ply carbon fiber thermoplastic composites by magnetic induction

For joining and repair of continuous fiber thermoplastic composites, induction heating has been viewed a strong candidate. Induction heating employs an applied alternating magnetic field, which induces a rotational emf in a grid of conductive carbon fibers, which are then used to carry resulting currents. In continuous carbon fiber crossply composites the available paths for “eddy current” loops are along the network of conductive carbon fibers. For this to occur, an electrical transfer must take place between crossing fibers in adjacent plies. Tests involving variable thicknesses of interply neat film layers have been performed to provide insight into the mechanisms taking place. These tests indicate that the primary mechanism for heating in such laminates is dielectric losses in the polymeric region between fibers in adjacent planes that form the conductive loop. Therefore, heating is not uniform in such composites despite a uniform magnetic flux. Heating patterns were viewed using liquid crystal materials and E-type thermocouples. Several factors leading to nonhomogeneous thermal distributions have been considered, including current density effects, internal emf cancellation, and rotational field effects. Global and local considerations are addressed, a localized model is proposed, and the corresponding theory is developed qualifying the early results. Additional testing has supported the theory.     

Simple protocols to determine dust potentials from cattle feedlot soil and surface samples

Cattle feedlot dust is an annoyance and may be a route for nutrient transport, odor emission, and pathogen dispersion, but important environmental factors that contribute to dust emissions are poorly characterized. A general protocol was devised to test feedlot samples for their ability to produce dust under a variety of environmental conditions. A blender was modified to produce dust from a variety of dried feedlot surface and soil samples and collect airborne particles on glass fiber filters by vacuum collection. A general blending protocol optimized for sample volume (150-175 cm3), blending time (5 min of pre-blending), and dust collection time (15 s) provided consistent dust measurements for all samples tested. The procedure performed well on samples that varied in organic matter content, but was restricted to samples containing less than 200 to 700 g H2O kg(-1) dry matter (DM). When applied to field samples, the technique demonstrated considerable spatial variability between feedlot pen sites. Mechanistically, dust potential was related to moisture and organic matter content. An alternative protocol also demonstrated differences within pen sites in maximum dust potential and dust airborne residence time. The two protocols were not intended, nor are they suitable, for predicting actual particulate matter emissions from agricultural sources. Rather, the protocols rapidly and inexpensively compared the potential for dust emission from samples of differing composition under a variety of environmental conditions.     

Intellectual performance and ego depletion: Role of the self in logical reasoning and other information processing.

Some complex thinking requires active guidance by the self, but simpler mental activities do not. Depletion of the self's regulatory resources should therefore impair the former and not the latter. Resource depletion was manipulated by having some participants initially regulate attention (Studies 1 and 3) or emotion (Study 2). As compared with no-regulation participants who did not perform such exercises, depleted participants performed worse at logic and reasoning (Study 1), cognitive extrapolation (Study 2), and a test of thoughtful reading comprehension (Study 3). The same manipulations failed to cause decrements on a test of general knowledge (Study 2) or on memorization and recall of nonsense syllables (Study 3). Successful performance at complex thinking may therefore rely on limited regulatory resources. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal stability in bulk cryomilled ultrafine-grained 5083 Al alloy

Thermal stability in bulk ultrafine-grained (UFG) 5083 Al that was processed by gas atomization followed by cryomilling, consolidation, and extrusion, and that exhibited an average grain size of 305 nm, was investigated in the temperature range of 473 to 673 K (0.55 to 0.79 T _m , where T _m is the melting temperature of the material) for different annealing times. Appreciable grain growth was observed at temperatures > 573 K, whereas there was limited grain growth at temperatures < 573 K even after long annealing times. The values of the grain growth exponent, n, deduced from the grain growth data were higher than the value of 2 predicted from elementary grain growth theories. The discrepancy was attributed to the operation of strong pinning forces on boundaries during the annealing treatment. An examination of the microstructure of the alloy suggests that the origin of the pinning forces is most likely related to the presence of dispersion particles, which are mostly introduced during cryomilling. Two-grain growth regimes were identified: the low-temperature region (<573 K) and the high-temperature region (>573 K). For temperatures lower than 573 K, the activation energy of 25 ± 5 kJ/mol was determined. It is suggested that this low activation energy represents the energy for the reordering of grain boundaries in the UFG material. For temperatures higher than 573 K, an activation energy of 124 ± 5 kJ/mol was measured. This value of activation energy, 124 ± 5 kJ/mol, lies between that for grain boundary diffusion and lattice diffusion in analogous aluminum polycrystalline systems. The results show that the strength and ductility of bulk UFG 5083 Al, as obtained from tensile tests, correlate well with substructural changes introduced in the alloy by the annealing treatment.     

Electrical and optical studies of ZnO:Ga thin films fabricated via the sol–gel technique

The effects of dopant (Ga) concentration, post-heat treatment temperatures, and different heat treatment environments on the morphology, electrical and optical properties of ZnO films were studied. ZnO films doped with Ga are derived from non-alkoxide zinc acetate via the alcoholic route by a sol–gel dip-coating technique. Introduction of Ga, as a dopant, can reduce crystallite size, which is attributed to the increased number of nucleation centers. Grain growth was also observed at high post-heat treatment temperature. It was discovered that different post-heat treatment environments (air or reduced atmosphere) did not change the structure orientation, microstructure shapes and size. It was found that the sheet resistance, R_s could be reduced by an order of magnitude, using post-heat treatment in reduced atmosphere (4%H₂–96%N₂).     

Regeneration studies on nickel molybdate catalysts used for the upgrading of coal-derived liquids

Nickel molybdate catalysts used in several different upgrading reactions of coal-derived materials from low-rank Australian coals have been regenerated and their activity assessed using a number of physical and chemical techniques. Regeneration of spent coked catalysts for 20 hours in air at 450°C was sufficient to restore chemical hydrogenation activity to catalyst used for pre-asphaltene, asphaltene and oil upgrading, provided poisoning of the catalyst surface by other impurities, principally chlorine-containing molecules, had not occurred.     

Preparation of La2Zr2O7 by Sol—Gel Route

The La₂Zr₂O₇ phase was prepared from metal acetylacetonates by a sol—gel route without any intermediate phase formation. X-ray peaks appeared at a temperature as low as 500°C at the positions expected for La₂Zr₂O₇, although they were broad. The crystal structure of La₂Zr₂O₇ was found to be of the fluorite type below 900°C and of thepyrochlore type above 1000°C. The substitution of a small amount of Eu for La was carried out to investigate the crystal structure from the viewpoint of fluorescence, and these results confirmed the formation of fluorite type La₂Zr₂O₇ below 900°C.