Pressure effects on flow and fracture of Be-Al alloys

The flow and fracture behavior of Be-Al alloys were determined in tension with different levels of superimposed pressure. The Be-Al alloys were prepared by Brush Wellman, Inc. (Cleveland, OH) from prealloyed powders processed to either a hot isostatically pressed (“hipped”) or cold isostatically pressed and extruded condition. Significant effects of pressure on both the flow and ductility have been observed at room temperature, with implications on the formability of these materials. The effects of changes in processing conditions and stress state on the flow and fracture behavior are summarized in addition to both optical and scanning electron microscopy (SEM) examination of the fracture surfaces. Separate other studies on the alloy constituents (e.g., Al and Be) are also reported. The results are also compared to previous works on monolithic materials and composites tested with high pressure.     

Analysis of clinical trial data: The problem of outcome overlap.

The immediate goal of any clinical trial is to determine to which of a specified set of treatments future patients are to be assigned, particularly when analyzing data from clinical trials. When the outcome distributions of Experimental (E) and Control (C) treatments overlap, differences between treatment group means are not conclusive and may not be very informative, so a display of the overlapped frequency distributions and a summary measure of the probability of a random patient in E doing better than a random patient in C are needed. When outcome distributions overlap, the question of statistical model becomes crucial even when there are very significant differences between group means and very large effect sizes. Determining what patient variables interact with treatments is the route to optimal assignment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of mastication on the distribution of molecular weights and on the mechanical properties of native and commercial dental gutta percha (trans-polyisoprene)

Mastication of gutta percha (trans-polyisoprene) resulted in the selective scission of molecules, producing a narrower distribution of lower molecular weights. The mechanical properties of the samples also underwent a significant change due to mastication. The greater the content of incompatible substances (salts and oxides) in commercial gutta percha. the more substantial were these effects. The atmosphere (air, N₂, O₂) in which the experiments were conducted yielded significantly different results. The decrease in molecular weight was far greater in an O₂ atmosphere than under a current of nitrogen or air, owing to the combination of double bonds with O₂.