Plastic deformation kinetics of fine-grained MgO in tension

The plastic deformation kinetics of 99.4% MgO (d _o = 5.3 m) was investigated at 1500°–1600°C in uniaxial tension. It was determined that the stress exponent n 1 and the activation energy Q = 204 kJ/mole. Neither the present results on MgO, nor data in the literature on MgO and other oxide ceramics, can be fully explained by the models usually proposed for the plastic deformation of fine-grained oxide ceramics. The present results are however in good agreement with the model for grain boundary diffusion plastic flow recently developed by Kim, Estrin and Bush.     

Quality-aware images.

We propose the concept of quality-aware image, in which certain extracted features of the original (high-quality) image are embedded into the image data as invisible hidden messages. When a distorted version of such an image is received, users can decode the hidden messages and use them to provide an objective measure of the quality of the distorted image. To demonstrate the idea, we build a practical quality-aware image encoding, decoding and quality analysis system, which employs: 1) a novel reduced-reference image quality assessment algorithm based on a statistical model of natural images and 2) a previously developed quantization watermarking-based data hiding technique in the wavelet transform domain.     

Endosonographic image of a retrorectal bowel duplication: report of a case

PURPOSE: Endosonographic image and surgical therapy of a retrorectal bowel duplication are described. METHODS, RESULTS, AND CONCLUSIONS: Compared with standard investigations, the most accurate information about a retrorectal mass in a 35-year-old woman could be obtained by means of endorectal ultrasound. Guided by endorectal ultrasound, the mass was excised using a transanal-transrectal approach, and Kraske's operation could be avoided. Additionally, histopathologic analysis of this rare disease is presented.     

Marijuana use and treatment outcome in cocaine-dependent patients.

Marijuana use was assessed in 186 people seeking treatment for cocaine dependence. Comparisons were made between clients who did and did not report using marijuana and between marijuana users who did and did not meet diagnostic criteria for marijuana dependence. The relationship between marijuana use and treatment outcome was also explored. A high rate of current marijuana use (59%) was observed at intake, and the majority of the marijuana users (74%) used marijuana at some point during treatment. Marijuana use at intake was associated with increased psychosocial impairment and substance-use severity. However, no significant adverse relations were observed between marijuana use at intake or during treatment and treatment outcome. Such functional independence may have important implications for addressing marijuana use during treatment for cocaine dependence. These findings should be interpreted with caution pending replication in prospective studies and with other treatment approaches. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On convection in aluminum reduction cells

The convection pattern in the bath electrolyte and the cathode metal of 150 kamp prebaked anode aluminum reduction cells has been studied by means of radioactive tracers. The initial distribution of the tracers—²⁴Na for the bath and¹⁹⁸Au for the metal phase-indicates a fast circulating movement with vortices at the ends in both phases. Circulation rates up to 100 cm per sec were observed, and an average value seemed to be 10 cm per sec. The implications of the convection on the mechanism of the secondary reactions, the dissolution of alumina in the bath electrolyte and the distribution of carbon particles in the cell are discussed.     

Effect of Sediment Copper on the Distribution of Benthic Macroinvertebrates in the Keweenaw Waterway

Benthic macroinvertebrates, sediment copper, and sediment particle size were examined in two areas of the Keweenaw Waterway. The north area is downdrift from deposits of copper tailings. South area sediment averaged 27% silt and clay and north area sediment 66%. South area sediment had an average copper content of 33 mg/kg and north area sediment 589 mg/kg. The number of invertebrates was 4.3 times greater in the south than the north. The average number of taxa at south stations was 20 and at north stations 8. Mollusks, mayflies, and crustaceans were common in the south but rare or absent in the north. Hexagenia was the most abundant animal in the south. A single individual was found in the north, at the only north station with low sediment copper. Three north stations with sediment particle size similar to south stations had the same restricted fauna of chironomids and oligochaetes as that found at other north stations. Equitability and Shannon-Wiener diversity values for most north stations did not indicate pollution because of the extremely low, and thus, even numbers of individuals collected in all taxa. Twenty-six taxa were common to both areas. Four taxa, found only in the north, were represented by five individuals. Twenty-five taxa, found only in the south, were represented by 1,007 individuals. The likely cause of the reduced invertebrate fauna in the north area is high levels of sediment copper.     

Hexagonal dislocation networks in titanium

Hexagonal dislocation networks which occurred in as-annealed commercial Ti-A 50 rod and following partial extrusion under hydrostatic pressure at room temperature were studied using transmission electron microscopy. For the as-annealed condition networks were observed on the prism, basal and {2•1•1x} planes, while for the extrusion networks were only observed on the basal plane. The various stages in the development of the networks are presented and mechanisms by which they form are proposed. The self energies of the dislocation hexagons constituting the various networks are calculated using the equations proposed by de Wit and Ruff. They increase in the order: a) networks on the basal plane in the as-annealed condition, b) networks on the prism plane in the asannealed condition and c) networks on the basal plane in the partially extruded condition. This paper is based on Doctoral Thesis presented in October 1973 by S. P. AGRAWAL to the Department of Metallurgical Engineering and Materials Science at the University of Kentucky.