A dissimilar metal weldment consisting of SA508-309L-308L-304L is widely used in light-water nuclear reactors. These weldments demonstrate dissimilar susceptibility to stress corrosion cracking that are related to the microstructure, properties, and residual stress. In this work, microstructures, hardness, and the residual stress distribution of the dissimilar metal weldments were investigated, with the correlation of increased hardness in the heat-affected zone (HAZ) to the microstructure. 304L HAZ demonstrated similar grain morphology as the base material, and the increase in hardness was primarily attributed to the increased dislocation density. SA508 HAZ demonstrated a change of grain morphology resulting from the different peak temperatures and cooling rates. The increased hardness in the SA508 HAZ was attributed to the refined grain morphology, higher dislocation density, and higher number density of precipitates. A ~ 20–30-μm-wide martensitic zone formed at the fusion boundary of SA508-309L, where Cr-rich carbide precipitates were observed, with the average size and the number density of 44.1 ± 16.9 nm and 1.5 × 1021 m−3, respectively. Residual stress results demonstrated the largest tensile stress at 309L butter, indicating its high cracking susceptibility.
Aeration properties of acidified casein-stabilized emulsions containing liquid oil droplets have been compared to the whipping of dairy cream. The foam systems were characterized in terms of overrun, microstructure, drainage stability, and rheology. With acidification using glucono-δ-lactone, the casein-stabilized emulsions could be aerated to give foams of far higher overrun (>600%) than whipped cream (∼120%). The development of foam volume, stability and rheology in the aerated casein-stabilized emulsion systems was found to be strongly dependent on the pH and the concentration of added calcium ions. Whereas whipped cream is stabilized by partially coalesced fat globules, the casein emulsion foams are stabilized by aggregation (gelation) of the protein coat surrounding the oil droplets. Casein emulsion foams formed at low pH were found to be more stable than whipped cream, whilst those formed at high pH were predominantly liquid-like and unstable. Instability arose in the acidified casein emulsion foams mainly through gel syneresis. We conclude that there are substantial textural differences between whipped cream and acidified casein emulsion foams, especially in terms of the small-deformation rheology and the extent of the linear viscoelastic regime. 相似文献
This article documents that the hydrogen economy continues to attract significant attention among politicians, the media, and some academics. We believe that an explanation lies in the way that the hydrogen economy fulfills psychological and cultural needs related to a future world where energy is abundant, cheap, and pollution-free, a “fantasy” that manifests itself with the idea that society can continue to operate without limits imposed by population growth and the destruction of the environment. The article begins by explaining its research methodology consisting of two literature reviews, research interviews of energy experts, and the application of symbolic convergence theory, a general communications theory about the construction of rhetorical fantasies. We then identify a host of socio-technical challenges to explain why the creation of a hydrogen economy would present immense (and possibly intractable) obstacles, an argument supplemented by our research interviews. Next, we employ symbolic convergence theory to identify five prevalent fantasy themes and rhetorical visions—independence, patriotism, progress, democratization, and inevitability—in academic and public discussions in favor of the hydrogen economy. We conclude by offering implications for scholarship relating to energy policy more broadly. 相似文献
The current study evaluated the associations between externalizing psychopathology and marital adjustment in a combined sample of 1,805 married couples. We further considered the role of personality in these associations, as personality has been found to predict both the development of externalizing psychopathology as well as marital distress and instability. Diagnostic interviews assessed conduct disorder, adult symptoms of antisocial personality disorder, and alcohol dependence. Personality was assessed using the Multidimensional Personality Questionnaire. The Dyadic Adjustment Scale was used to measure marital adjustment. Results indicate that more externalizing psychopathology, greater negative emotionality, and lower communal positive emotionality were associated with reduced marital adjustment in both individuals and their spouses. Low constraint was associated with reduced marital adjustment for individuals but not for their spouses. Multivariate analyses indicated externalizing psychopathology continued to predict marital adjustment even when accounting for overlap with personality. These results highlight the importance of examining the presence of externalizing psychopathology and the personality attributes of both members of a dyad when considering psychological predictors of marital adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
In this report, we conducted a secondary analysis of the Treatment of SSRI-Resistant Depression in Adolescents (TORDIA) study to explore the impact of specific cognitive–behavioral therapy (CBT) treatment components on outcome. In TORDIA, 334 youths (ages 12 to 18 years) with major depressive disorder who had failed to respond to an adequate course of selective serotonin reuptake inhibitor (SSRI) medication were randomized to a medication switch (either to an alternative SSRI or venlafaxine) with or without 12 weeks of adjunctive CBT. Participants who had more than 9 CBT sessions were 2.5 times more likely to have adequate treatment response than those who had 9 or fewer sessions. CBT participants who received problem-solving and social skills treatment components, controlling for number of sessions and other confounding variables, were 2.3 and 2.6 times, respectively, more likely to have a positive response. These preliminary findings underscore the importance of receiving an adequate number of sessions to attain an adequate clinical response. Finally, social skills and problem solving may be active elements in CBT for adolescent depression and should be considered in treatment by those working with seriously depressed youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Presents an introduction to a special issue of the Journal of Counseling Psychology. This editorial discusses advances in research with sexual minority people. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The influence of chitosan and gum arabic mixtures on the behaviour of o/w emulsions has been investigated at pH = 3.0. The emulsion behaviour, properties and microstructure were found to be greatly dependent on the precise gum arabic to chitosan ratio. Mixing of gum arabic with chitosan leads to the formation of coacervates of a size dependent on their ratio. Incorporation of low gum arabic to chitosan weight ratios into whey protein-coated emulsions causes depletion flocculation and gravity-induced phase separation. Increasing the polysaccharide weight ratio further, a droplet network with a rather high viscosity (at low shear stress) is generated, which prevents or even inhibits phase separation. At even higher gum arabic to chitosan ratios, the emulsion droplets were immobilised into clusters of an insoluble ternary matrix. Although the emulsion droplet charge had the same sign as that of the coacervates, clusters of oil droplets in a ternary matrix were generated. A mechanism to explain the behaviour of the whey protein-stabilised o/w emulsions is described on the basis of confocal and phase contrast microscopic observations, rheological data, zeta potential measurements, particle size analysis and visual assessment of the macroscopic phase separation events. 相似文献
The authors respond to Bensley’s (see record 2009-12731-009) comment on their alternative formulation of critical thinking in psychology (see record 2008-11592-004). They argue that Bensley’s defense of the traditional critical thinking approach—which they term scientific analytic reasoning (SAR)—fails to address their main objections to SAR and their reasons for presenting an alternative. In particular, the openness, fairness, and generativity that Bensley references as strengths of SAR are themselves informed by scientific analytic assumptions and values, which, they argue, illustrates their original contention—that SAR offers an insular and insufficiently critical approach to critical thinking. The authors conclude by calling for future developments in critical thinking that are not driven by an implicit SAR agenda. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Abstract Increasing attention to watershed management is part of an international policy trend toward integrated water resource management. Integration is multidimensional—across sectors, administrative regions, ministerial portfolios and levels of hydrologic structure and socioeconomic organization. Collective action is key. Individuals need to work effectively together to share common water points; upstream land users and downstream water consumers need to manage and resolve potential conflicts over water quantity and quality, while all the industries, farming communities, urban residents and public agencies that have interests in resource use and environmental quality need to agree on development and conservation objectives and approaches at the basin level. Initiatives that seek to foster collective action in watersheds need to account for the very different interests in water and watershed management. While there may be relatively straightforward ways to foster collective action at a local scale, some forms of collective action may, in fact, be detrimental to other stakeholders. In the developing world in particular, there are often geographic pockets and social groups that are chronically disadvantaged in collective and public processes. Water-users' associations and basin authorities may exacerbate these disparities and further marginalize already poor people. New statutory institutions may intentionally or inadvertently disempower effective customary local institutions. To enable project and program designers to address these challenges better, this paper lays out a framework for assessing the potential for, and implications of, individual and collective decisions in a watershed context. The framework integrates concepts drawn from the biophysical and social sciences, including new perspectives on watershed components, poverty, and collective action. Collective action is seen as a fractal process: collective action for water management at one level of social-spatial organization can have spillover effects at lower and higher levels of social-spatial resolution. To be pro-poor, watershed-management institutions must be genuinely inclusive, deliberately recognizing the interests, perspectives and knowledge of groups that may be systematically excluded from other political and social processes. Researchers, evaluators, watershed-management practitioners and others who apply the framework should be better placed to lay the foundations for that illusive goal: pro-poor, inclusive and resource-conserving development. 相似文献