Near-tip behavior of deflected creep cracks

Near-tip displacement fields of a creep crack which exhibited moderate deflection from its initially mode I condition have been measured using the stereoimaging technique. From the measured displacement fields, near-tip strains and crack opening displacements (CODs) are obtained and compared with existing asymptotic solutions for stationary, deflected cracks. The comparison reveals that the near-tip strain field and CODs of a stationary deflected creep crack in stainless steel (creep exponent of 8) are of the Riedel-Rice type. The degree of mode mixity is also adequately predicted for the deflected crack. The results for stainless steel are compared with previous results for a glass-ceramic (creep exponent of 1.5), to assess the range of applicability of the RR field. Discrepancies between theory and experiment are discussed in terms of the dominant creep mechanism, which is dislocation creep for the stainless steel and grain boundary sliding for the glass-ceramic.     

Localization of human transcription factor TEF-4 and TEF-5 (TEAD2, TEAD3) genes to chromosomes 19q13.3 and 6p21.2 using fluorescence in situ hybridization and radiation hybrid analysis

The tetrapeptide Ala-lle-Gly-Met bound to a Wang resin via the methionine residue was studied by NMR under MAS conditions and compared to the same peptide in solution. The bound peptide exhibits average linewidths superior to those observed for the peptide in solution. The origin of the residual NMR linewidth observed for the bound form was investigated. The dynamics of the peptide is shown to be only marginally responsible for the increased linewidth; the major cause of the line broadening appears to be nonaveraged magnetic susceptibility differences.     

Biological Removal of Gaseous VOCs from Automotive Painting Operations

Among the pollutants that automotive plants produce, volatile organic compound (VOC) emissions due to paint solvents from painting operations are the largest in quantity. The current control process, based on vapor-phase adsorption followed by thermal oxidation, is costly to install and operate. At Ford, a cost-effective method of removing VOCs has been investigated that involves converting an existing spraybooth scrubber system to a biological reactor. This paper reports the results of a pilot-scale investigation in which two activated-sludge bioreactors, one with and the other without powdered activated carbon (PAC), were operated in parallel for 16 months. The primary findings include (1) The biological VOC removal process was technically feasible, and a scrubber system at a typical assembly plant is sufficiently large to handle the solvent loading used under normal vehicle-production conditions; (2) as compared to the adsorption∕thermal oxidation process, the biological process was found to be comparable in VOC removal efficiency, an order of magnitude more cost-effective in capital cost, and a factor of two more cost-effective in operating and maintenance cost; and (3) the bioreactors effectively captured and degraded hydrophilic paint solvents (methyl ethyl ketone, n-butanol, and butyl cellosolve) that were fed via the vapor phase. Toluene, a hydrophobic solvent, was also well-captured and degraded (74 to 91% without PAC and 86 to 93% with PAC).     

Technology watch in the construction sector: why and how?

‘Technology watch’, like ‘innovation’, is a process term. Large corporations in high-tech industries use technology watch regularly to facilitate the adoption of innovations, where it is associated with parallel ‘watch’ activities in social, legal and environmental areas. The information (yielded by technology watch) is either unrefined or refined to give it added value for decision making. The technology watch process involves steps of collection, analysis and dissemination, implicating a watch team and domain experts. In small and medium enterprises (SMEs), particularly in the construction sector, special problems arise because of the lack of interest in innovation and because of the shortage of resources, suggesting the creation of ‘relay stations’ in the technology watch process. Current changes in the organization of the construction process, however, are changing the industry's structure, suggesting that there may be a new need for the kinds of information that technology watch can provide. e Veille technologique f comme e innovation f sont des termes de processus. Dans le secteur des industries de pointe, les grandes entreprises font régulièrement appel à la veille technologique pour faciliter l'adoption d'innovations, associant ainsi les activités de veille aux domains social, juridique et environnemental. Les informations qui découlent de la veille technologique peuvent être brutes ou affinées afin de leur donner une valeur ajoutée qui sera particulièrement utile lors de la prise de décisions. La veille technologique consiste à recueillir, analyser et diffuser des données - ce qui implique un travail d'équipe et le recours à des experts. Dans les PME, notamment dans le secteur de la construction, surgissent des problèmes particuliers du fait du manque d'intérêt pour l'innovation et de la pénurie des ressources; cete situation suggère la création de stations-relais dans le processus de veille technologique. Actuellement on observe des changements dans l'organisation des processus de construction qui modifient la structure de cette industrie ; il est possible que cette nouvelle donne suscite un nouveau besoin pour le type d'information que la veille technologique peut fournir.     

Sabbatical leave: Who gains and how much?

A rigorous quasi-experiment tested the ameliorative effects of a sabbatical leave, a special case of respite from routine work. We hypothesized that (a) respite increases resource level and well-being and (b) individual differences and respite features moderate respite effects. A sample of 129 faculty members on sabbatical and 129 matched controls completed measures of resource gain, resource loss, and well-being before, during, and after the sabbatical. Among the sabbatees, resource loss declined and resource gain and well-being rose during the sabbatical. The comparison group showed no change. Moderation analysis revealed that those who reported higher respite self-efficacy and greater control, were more detached, had a more positive sabbatical experience, and spent their sabbatical outside their home country enjoyed more enhanced well-being than others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of PSCF and CPF to PMF-Modeled Sources of PM2.5 in Pittsburgh

Ambient PM _2.5 composition data in Pittsburgh, PA have been used with Positive Matrix Factorization (PMF) to determine the major sources of PM _2.5 sampled. This paper describes the use of the potential source contribution function (PSCF) with the PMF-modeled source contributions to locate the sources in a grid of 0.1° × 0.1° cells. The domain extends from the Pittsburgh Supersite at 40.44°N, 79.94°W over the range 35°–50° north latitude and 75°–90° west longitude. Six-hour back trajectories have been obtained from HYSPLIT four times each day for the 13 months of the study for use with PSCF. Using the results, higher probability locations are compared with known locations of specific source types, based on information from the EPA Toxic Release Inventory (TRI) and the EPA AIRS Database. PSCF results for several sources are compared to the conditional probability function (CPF) analysis, which uses 15-minute wind direction data to determine the most probable direction of a source. Using PSCF and CPF together aids in interpretation of potential source regions. The selenium and sulfate factor source locations are regional, while the lead, cadmium, and specialty steel factor source locations are local. The gallium-rich and Fe, Mn, and Zn factor source locations are potentially both local and regional. The nitrate, vehicle emissions and road dust, wood combustion, vegetative detritus and cooking, and crustal material factor CPF and PSCF results were inconclusive as sources of these factors exist in all directions from the site and therefore one would not expect a clear probability field in any one direction.     

Extending the dynamic range of fibre length and fibre aspect ratios by automated image analysis

An automatic image analysis system has been developed, that is capable of scanning a large sample area (70 mm × 70 mm) using transmitted light microscopy. The analysis, based on transparent algorithms, successfully discriminates between overlapping and touching fibres, so that sample preparation time is minimized. The system utilizes overlapping image frames to reconstruct partial fibre images and impart unique fibre length information in the range micrometres to millimetres. The software has been made adaptable to enable the accurate measurement of fibre lengths for fibres that curve over many millimetres. Data are presented illustrating the accurate measurement of fibre lengths over a large range of fibre aspect ratios.     

Prediction of polymer tube life for solar hot water systems: A model of antioxidant loss

The successful use of polymer components in solar hot water systems requires an understanding and method of predicting material degradation in water. The relevant degradation mechanism is oxidation. Degradation from oxidation can be delayed through the use of antioxidant additives. However, once the antioxidants have been depleted, oxidation of the polymer and subsequent loss of mechanical integrity occur rapidly. In this study, antioxidant loss from polymer tubes is modeled. Dimensional analysis and results of the model show the rate of antioxidant loss is controlled by diffusion through the polymer. The diffusion time scale is dictated by the tube wall thickness. Antioxidant concentration profiles and depletion rates are presented for three representative tube geometries and temperatures of 293 and 333 K. The time to deplete 90% of the antioxidant is on the order of 1000–10,000 h.