Morphology and Growth Kinetics of 3He Crystals Below 1 mK

The shapes as well as the growth and melting properties of bcc-³He single crystals have been investigated with a low temperature Fabry-Pérot interferometer. Eleven types of facets were clearly identified during slow crystal growth at the temperature of 0.55 mK, where the solid is in the antiferromagnetically ordered u2d2 phase. The growth rates of the individual facets have been measured and the results indicate significant growth anisotropy. The observed linear dependence of the growth velocity on the driving force shows that facets grow due to the presence of screw dislocations, while the step velocity is limited by the spin wave velocity due to the strong interaction of the moving step with magnons in the solid. The measured growth rates of the facets and the assumed growth mechanism gave us the unique opportunity to obtain the step free energies for ten different types of facets observed during a single growth sequence. The dependence of the free energy of the step on the step height is compared with predictions of the weak- and strong-coupling models. Our results suggest that ³He crystals have rather strong coupling of the liquid/solid interface to the crystal lattice and that the step-step interactions are of elastic origin.     

Parallel Algorithms for Perceptual Grouping on Distributed Memory Machines

Perceptual grouping is a key intermediate-level vision problem. Parallel solutions to this problem are characterized by uneven distribution of symbolic features among the processors, unbalanced workload, and irregular interprocessor data dependency caused by the input image. In this paper, we propose two load-balancing techniques for parallelizing perceptual grouping on distributed-memory machines. By using an initial workload estimate, we first partition the computations to distribute the workload across the processors. In addition, we asynchronously perform ongoing task migrations to adapt to the unbalanced workload which may evolve differently from the initial estimate. We also discuss two strategies to manage the irregular interprocessor data dependency. To illustrate our ideas, perceptual grouping steps used in an integrated vision system for building detection are used as examples. Our experimental results show that, given 8K extracted line segments from a 1K × 1K image, both the line and junction grouping steps can be completed in 0.644 s on a 32-node SP2 and in 0.585 s on a 32-node T3D. For the same grouping steps, a serial implementation requires 10.550 s and 10.023 s on a single node of SP2 and T3D, respectively. The implementations were performed using the message passing interface standard and are portable to other high performance computing platforms.     

Influence of running water on the heat transfer in continuous casting

The influence of running water on spray water cooling is experimentally looked at with the aid of a stationary working experimental plant. The running water was fed separately to the sample from above as a defined water film by using a slot nozzle. In addition to the spray nozzle pre-pressure, the velocity of the running water at the slot nozzle exit and the temperature of the running water, the angle of inclination of the sample plane was also varied. By employing three different full cone spray nozzles and setting different nozzle distances, a range of 450 to 2000 l/(m²·min) of the water impingement density was covered. To estimate the marginal influences, samples of 20 × 20 mm as well as 30 × 30 mm were used. Studies of initially pure spray water cooling without the additional running water film revealed a dependency of the heat transfer on the spray water impingement density, the spray water velocity and also the angle of inclination of the sample plane. For nozzles with a low water impingement density, a superimposing of a running water film on the spray water revealed a sharp increase in the heat transfer coefficients compared to pure spray water cooling. For nozzles with a high water impingement density and, therefore, with a high heat transfer already even for pure spray water cooling, the increase of the heat transfer coefficient is minor.     

Predicting participation in a dietary intervention to lower cholesterol among individuals with hyperlipidemia.

Adult men and women (N?=?8,748) were given blood cholesterol tests and completed a measure of fat intake and a staging questionnaire that assessed readiness to adopt a cholesterol-lowering diet. Eligibility for the trial was based on plasma cholesterol levels and self-reported dietary intake. Of 772 eligible participants, 545 (70.6%) agreed to join. In multivariate analyses, joiners did not differ from nonjoiners by age, total cholesterol levels, or self-reported dietary fat intake. Women were more likely than men to join the study. Individuals in the preparation stage (defined on the basis of a staging algorithm derived from the transtheoretical model of change) were more likely to join the trial than were precontemplators. An understanding of the determinants of participation in a dietary intervention may be important in the enhancement of high-risk individuals' acceptance of recommendations to make dietary changes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Small and Large Scale Fire Experiments with Electric Cables under Well-Ventilated and Vitiated Conditions

Results from a series of small scale (using the DIN 53 436 tube furnace) and large scale experiments (using the IEC 60332-3 rig) are presented for two types of power transmission cables used in buildings. The results are unique in that they catalogue the production of a wide variety of organic and inorganic species under different fire conditions. The experiments were conducted to provide input to an LCA model and the specific organic species studied in detail have been chosen based on the information required by the LCA model.During the process of this study it became apparent that information concerning quantitative organic species evolution from cable fires is lacking in the open literature. This paper aims to provide such information for two specific sets of fire conditions, i.e., a well-ventilated and a vitiated cable riser fire.     

Differences in the catalytic efficiencies of allelic variants of glutathione transferase P1-1 towards carcinogenic diol epoxides of polycyclic aromatic hydrocarbons

Recently, we found a 13-lipoxygenase in germinating cucumber cotyledons, which was located at the lipid body membrane. Based on its products formed mobilization of storage lipids seems to be initiated by this 13-lipoxygenase. For biochemical characterization its cDNA was expressed as His-tagged protein. Active recombinant enzyme was obtained from low temperature cultivation of E. coli after affinity purification. It (i) exhibited an unchanged region specificity, and (ii) showed a pH optimum of 7.2 against trilinolein as substrate. We compared its ability to oxygenate trilinolein with the one of another 13-lipoxygenase, soybean lipoxygenase-1. At the pH optimum of soybean lipoxygenase-1 (9.0), trilinolein was oxygenated only to 28% of the amount converted by the lipid body lipoxygenase. Moreover, trilinolein oxygenation by soybean lipoxygenase-1 leads mainly to monohydroperoxy derivatives, whereas oxygenation by lipid body LOX leads to a trihydroperoxy derivative.     

Measurements on the Surface Tension of 3He Crystals near 100 mK

No Heading ³He crystals start to show facets on their surface only at about 100 mK, well below the roughening transition temperature, and the reason for this change of the surface state is not clear yet. However, the most important characteristics of the crystal surface, the surface tension, was not measured in this temperature range before. We report our observations on the equilibrium shape of the ³He crystals in the temperature range of 77...100 mK. The surfaces tension was found to be isotropic and temperature—independent, and the corresponding value of the capillary length, = 0.93 ± 0.10 mm, is in a good agreement with the value measured at higher temperatures by Rolley et al.²PACS numbers: 68.35.Md 68.08.–p 67.80.–s     

Energy-Efficient Computations on FPGAs

Recently, energy dissipation for computations on FPGAs has become an important performance metric. In this paper, we summarize our recent efforts in developing an algorithm-level design methodology for optimizing the energy performance of FPGA based implementations. For kernels, our design methodology consists of four steps: domain selection, domain-specific energy modeling, domain-space exploration and low-level simulation. To achieve system-level energy-efficiency, we outline a design methodology that integrates the kernel-level design methodology. Both the design methodologies can be used to achieve not only energy-efficiency but also latency, area, and power efficiency. We consider signal processing kernels as illustrative examples and demonstrate energy and time efficient algorithms and implementations for these on FPGAs. Example energy performance optimization through algorithmic optimizations include the 29–51% improvement in energy performance for a matrix multiplication kernel, 57–78% improvement for a FFT kernel and the 10–60% improvement for a floating-point LU decomposition kernel over state-of-the-art implementations. Similarly, an improvement of 41 to 46% in energy performance was achieved by the system-level design approach over a greedy approach for a MVDR adaptive beamforming application. Finally we briefly describe a high-level tool for obtaining parameterized and energy-efficient designs on FPGAs.This work is supported by the National Science Foundation under award No. CCR-0311823.