High heat flux spray cooling with ammonia: Investigation of enhanced surfaces for CHF

A spray cooling study was conducted to investigate the effect of enhanced surfaces on Critical Heat Flux (CHF). Test surfaces involved micro-scale indentations and protrusions, macro (mm) scale pyramidal pin fins, and multi-scale structured surfaces, combining macro and micro-scale structures, along with a smooth surface that served as reference. Tests were conducted in a closed loop system using a vapor atomized spray nozzle with ammonia as the working fluid. Nominal flow rates were 1.6 ml/cm² s of liquid and 13.8 ml/cm² s of vapor, resulting in a pressure drop of 48 kPa. Results indicated that the multi-scale structured surface helped increase maximum heat flux limit by 18% over the reference smooth surface, to 910 W/cm² at nominal flow rate. During the additional CHF testing at higher flow rates, most heaters experienced failures before reaching CHF at heat fluxes above 950 W/cm². However, some enhanced surfaces can achieve CHF values of up to ≈1100 W/cm² with ≈67% spray cooling efficiency based on liquid usage. The results also shed some light on the current understanding of the spray cooling heat transfer mechanisms. Enhanced surfaces are found to be capable of retaining more liquid compared to a smooth surface, and efficiently spread the liquid film via capillary force within the structures. This important advantage delays the occurrence of dry patches at high heat fluxes, and leads to higher CHF. The present work demonstrated ammonia spray cooling as a unique alternative for challenging thermal management tasks that call for high heat flux removal while maintaining a low device temperature with a compact and efficient cooling scheme.     

Implementation of ultra high pressure water cutting for treatment of flushed chip seals in the US

This paper discusses implementation of ultra-high pressure (UHP) water cutting as a pavement maintenance strategy based on the first large-scale application of UHP water cutting for treatment of flushed chip seals in the USA. Data are from 13 field sites located in four different climatic regions in Texas. Production rates and treatment costs are sensitive to the UHP water cutter equipment, road surface condition, environmental factors and other variables. Production rates for UHP water cutting under Texas road conditions ranged from 490 m²/h to 1560 m²/h, average 830 m²/h, for treatment of light to heavy flushing. Turn-key unit costs for UHP water cutting varied from US $1.77/m² to US $2.08/m² for an average savings of 41% as compared to the cost of typical Texas maintenance solutions for treatment of flushed chip seals. Overall, UHP water cutting shows positive results in terms of treatment effectiveness, durability and production considerations.     

Evaluation of carvedilol-loaded microsponges with nanometric pores using response surface methodology

This study demonstrates the use of factorial design for the preparation of microsponges of carvedilol with nanometric pores using the response surface methodology and to establish the functional relationships between two operating variables of Eudragit RS100 and sucrose. The response variables selected for this study were percent drug entrapment (Y1), time taken to release 35% of drug (Y2), percent drug release after 24?h (Y3), percent dissolution efficiency (DE) (Y4) and the angle of repose (Y5). The overall calculated desirability was found to be 0.8065 for the optimised formulation OF1. The response surface analysis of the desirability function with the independent levels indicated that the overall desirability increases with high levels of Eudragit RS100 and sucrose content. The optimum robust formulation (OF1) contains high levels of Eudragit RS100 (400.0?mg) and sucrose (350.21?mg), satisfying the predetermined constraints and goals of all the selected response variables. The scanning electron microscopy of OF1 indicated the spherical shape of microsponges with numerous pores on the surface. The atomic force microscopic study suggested the presence of nanometric pores on the surface of microsponges which may facilitate the release of the drug. Compatibility studies using the Fourier transform infrared spectroscopy, X-ray diffraction and differential scanning calorimeter indicated the absence of any incompatibility between carvedilol and excipients used to prepare microsponges.     

Supporting Scientists' Everyday Work: Automating Scientific Workflows

An action research project involving scientists from the National Research Council Canada and the Institute for Ocean Technology analyzed difficulties in using software to collect data and manage processes. The project identified three requirements for increasing research productivity: ease of use for end users, managing scientific workflows, and facilitating software interoperability. On the basis of these requirements, the researchers developed Sweet, a software framework, to help automate scientific workflows.     

优化开关测量子系统软件,提高测试系统性能

人们期望自动化测试系统能够完成精密的测量,并从待测器件(DUT)上收集到各种数据.在大多数情况下,自动化的测试必须在保证测量精度的前提下,以尽可能短的时间完成,从而最大限度减少产品的成本和资本投入.本文将讨论最大限度减少自动化测试的时间和保证测量精度的一些技术手段.     

Covert visual orienting across the lifespan.

Three groups of 20 K–5th graders, 20 college students, and 20 older adults (mean age 72.8 yrs) were tested. The S's task was the speeded discrimination of "X" from "O", but of primary interest was the effect of a location cue that appeared prior to the target. Both an abrupt stimulus cue and a voluntary information cue were studied using response time measures. Eye movements were monitored to control for differences in the ability to maintain fixation. Exp 1 showed that in comparison with young adults, children were less able to sustain orienting over time, and senior adults required more time to use the cue. Exp 2 (using K–1st graders, 4th–5th graders, 20 college students, and 20 older adults) tested the relation between stimulus and information cues when they both occurred prior to a given target. All age groups were able to use information cues in the presence of conflicting stimulus cues, but young adults were better able to do so than either children or senior adults. Results are interpreted as support for the view that separate mechanisms underlie stimulus-based versus information-based spatial orienting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spatially resolved small-angle noncollinear interferometric autocorrelation of ultrashort pulses with microaxicon arrays.

Small-angle, noncollinear, first- and second-order interferometric autocorrelation experiments with Ti:sapphire laser pulses of 9-80-fs duration have been performed with microaxicon arrays. Predictions of short-pulse spatial frequency effects were verified by comparison of interference patterns of single elements and matrices. An angular spectrum of Gaussian-shaped axicons was analyzed on the basis of linear refraction. Experimental data indicate contributions to autocorrelation by nonlinear refraction and travel-time differences. The influence of the spectral bandwidth was separated from the pulse-duration-dependent effects. Spatially resolved information about the coherence time was delivered by the multichannel structure.     

Where am I? Distal cues use requires sensitivity to start location change in the rat.

Place learning is impaired when a single plus maze is moved between adjacent locations 33-120 cm apart. This maze translation creates distinct start locations but maintains a single goal location with respect to distal cues. Hippocampal cell recording data suggest the majority of place fields are tied to apparatus boundaries, not to distal cues, when an apparatus is moved these distances to the left or right. Thus, rats may fail to appreciate the existence of multiple start locations with respect to distal cues when the maze is moved in this way and their start location on the surface is constant. Performance on the single plus maze problem was improved when texture cues were correlated with different start locations. Place learning was supported when multiple start locations were provided on a single large surface (double plus maze), even though rats did not explore the entire surface. Place learning was also supported when random extensions were added to a double plus maze such that start locations, relative to surface boundaries, were not informative as to goal location. This outcome suggests sensitivity to multiple start locations is required for distal cue use in translational place problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Education Outreach

A survey is presented on the Education Outreach activities that are sponsored by the Department of Energy's Office of Fusion Energy Sciences, with emphasis on the scope of these activities and the history behind the effort.