Influence of Aging and Severe Plastic Deformation on the Shape Memory Behavior of Ti-50.6at%Ni

Martensitic phase transformations were investigated for Ti -50.6 at % Ni processed via severe plastic deformation (SPD) and subsequent aging for temperatures between 400 and 550C and times ranging from 1hr to 100hrs. Phase transformations of the SPD material were compared to material processed via solution treated at 800C and 850C for 1hr. Transformations were investigated with differential scanning calorimetry (DSC) and confirmed by X-ray diffraction (XRD) with optical microscopy being used to determine grain size. Solution treated samples displayed a single (1-1) B2↔B19\u27 transformation prior to and upon initial aging, i.e. 400C/1h, 450C/1/10h. Intermediate aging conditions, 450C/100h; 500C/1/10/100h; and 550C/1h, resulted in multiple B2↔B19\u27 transformations (2-2). Aging at 400C/10/100h, induced the R phase and 3-2 transformation behavior. Intensive aging caused the solution treated material and the SPD material to revert to a single (1-1) B19\u27↔B2 transformation. A 2-1 transformation was exhibited by the bulk of the SPD samples, i.e. unaged SPD, 400C and 450C at 1/10/100h, 500C 1/10h, 550C 100h. XRD of SPD material indicated the presence of metastable Ni4Ti3 precipitates prior to aging, and equilibrium Ni3Ti precipitates after aging for 500C/100h. Multiple peaks in the solution treated samples result from composition heterogeneities. 3-2 behavior is the result critical microstrains inducing the R phase. 2-1 behavior of the SPD material results from a homogenous microstructure and macrostrains which induce the R phase. Aging the SPD material causes recovery, suppressing the R phase transformation and increasing the Ms temperature, eventually resulting in a 1-1 transformation

Analysis Of Microseismic Location Accuracy For Hydraulic Fracturing At The DWTI Site, Jasper, Texas

This report presents the results of a feasibility study designed to assess whether microseismic location techniques can provide enough accuracy and precision to enable a high resolution study of the spatial distribution of microseismic events induced during a hydraulic fracture experiment. We calculated the 90% confidence regions for six synthetic microevent 'clusters' along the azimuth of a hydraulic fracture produced during Atlantic Richfield's 1993 Fracture Technology Field Demonstration Project in Jasper, Texas. Examination of the confidence regions for the absolute locations indicates that microseismic events can be confidently located for areas near the monitoring wells but away from the plane intersecting the two observation points. We determined that the resolution for events located at the ends of the fracture is poor but improves dramatically nearer the wells. The minimum dimensions of the 90% confidence regions for events within our study area are approximately 8 ft in the northwest-southeast direction, 3 ft in the northeast-southwest direction, and 3 ft in depth

Growth, performance and quality attributes of steers supplemented with high oleic soybean oil

Growing concerns with saturated fatty acids on human health has led to research being done to reduce saturated fatty acid levels in animal tissues. The objective of this study was to evaluate the effect of high oleic soybean oil on the performance, carcass composition and meat quaility of angus crossbred steers. 30 steers were sorted by weight using stratified sampling design into four pens, 2 being control and 2 being treatment. Control steers were fed a diet that included 3% regular soybean oil, while treatment steers were fed a diet with 3% high oleic soybean oil (HO). All animals were fed diets with soybean oil supplementation for a minimum of 63 days before harvest. After harvest, KPH weights and hot carcass weights were taken. Marbling score and longissimus dorsi area were assessed 48 hours after slaughter. Fat samples were taken from four different fat depots (subcutaneous, kidney, pelvic, heat (KPH), seam and intramuscular) and analyzed for fatty acids composition. PROC UNIVARIATE was ran and data more than three standard deviations from the mean was removed. Remaining data was analyzed using the PROC MIXED procedure of SAS 9.3. Greater DMI (P_0.01) was measured for cattle fed the HO diet and as a result DMI %BW was also significantly higher (P_0.01). However, the G:F was significantly less (P= 0.05) and the ending body weight had no difference.by William James ShirleyIncludes bibliographical reference

Temporally coherent interactive ray tracing

Journal ArticleAlthough ray tracing has been successfully applied to interactively render large datasets, supersampling pixels will not be practical in interactive applications for some time. Because large datasets tend to have subpixel detail, one-sample-per-pixel ray tracing can produce visually distracting popping and scintillaction. We present an algorithm that directs primary rays toward locations rendered in previous frames, thereby increasing temporal coherence. Our method tracks intersection points over time, and these tracked points are used as an oracle to aim rays for the next frame. This is in contrast to traditional image-based rendering techniques which advocate color reuse. We so acquire coherence between frames which reduces temporal artifacts without introducing significant processing overhead or causing unnecessary blur