Microstructure,Hardness, and Residual Stress of the Dissimilar Metal Weldments of SA508-309L/308L-304L

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.

     

Effects of solid lubricants in backward extrusion

In the present paper, some solid lubricants were tested in backward extrusion friction tests with flat-headed punches using aluminium at room temperature. The results showed that anti-seizure ability was improved when wax was added to the solid lubricant samples. In addition, a water-based graphite lubricant and an ultrahigh molecular weight polyethylene (UHMW-PE) lubricant were tested using aluminium workpieces heated to 500°C. The lubricity of the UHMW-PE lubricant was found to be superior to that of the graphite lubricant.     

A thermodynamic investigation of adsorbate‐adsorbate interactions of carbon dioxide on nanostructured carbons

A thermodynamic study of carbon dioxide adsorption on a zeolite‐templated carbon (ZTC), a superactivated carbon (MSC‐30), and an activated carbon (CNS‐201) was carried out at temperatures from 241 to 478 K and pressures up to 5.5?10⁶ Pa. Excess adsorption isotherms were fitted with generalized Langmuir‐type equations, allowing the isosteric heats of adsorption and adsorbed‐phase heat capacities to be obtained as a function of absolute adsorption. On MSC‐30, a superactivated carbon, the isosteric heat of carbon dioxide adsorption increases with occupancy from 19 to 21 kJ?mol^?1, before decreasing at high loading. This increase is attributed to attractive adsorbate–adsorbate intermolecular interactions as evidenced by the slope and magnitude of the increase in isosteric heat and the adsorbed‐phase heat capacities. An analysis of carbon dioxide adsorption on ZTC indicates a high degree of binding‐site homogeneity. A generalized Law of Corresponding States analysis indicates lower carbon dioxide adsorption than expected. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1026–1033, 2018     

Symbolic convergence and the hydrogen economy

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.     

Assessment of remnant unionid assemblages in a selection of Great Lakes coastal wetlands

Populations of native unionids have been in steady decline over the past century. The invasion of dreissenid mussels (Dreissena polymorpha and Dreissena rostriformis bugensis) in the mid-1980's impacted already imperiled unionid populations by greatly increasing their regional extinction rates. A selection of Great Lakes coastal wetlands around Michigan was surveyed to locate remnant populations of native unionids. Physical and chemical parameters were measured in coastal wetlands to evaluate the importance of these habitat parameters to remnant unionid assemblages. We assessed fouling rates by dreissenids on unionids and used artificial substrates to estimate dreissenid colonization densities. Live unionids were found in coastal wetlands of the Les Cheneaux Islands, the Lake St. Clair delta, and North Maumee Bay with significantly higher unionid fouling in the Les Cheneaux Islands compared to the other two sampling areas (F_2,76 = 4.97, p = 0.0095). No live unionids were documented in Beaver Island, Garden Island, Grand Traverse Bay, or Saginaw Bay wetlands. Dreissena colonization densities on artificial substrates averaged 19,213 m^− 2 at one site in North Maumee Bay, and 10,425 m^− 2 in Saginaw Bay, but no colonization occurred in the wetlands of Beaver Island, Garden Island, the Les Cheneaux Islands, or Grand Traverse Bay while Dreissena presence in the open water of these regions was evident. Dreissena colonization densities on artificial substrates increased with measures of anthropogenic disturbance and decreased with higher water level fluctuations and aerial exposure. Specific conductance, turbidity, and magnitude of water level fluctuations were important predictors of Dreissena colonization on artificial substrates.     

Externalizing psychopathology and marital adjustment in long-term marriages: Results from a large combined sample of married couples.

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)     

Effective components of TORDIA cognitive–behavioral therapy for adolescent depression: Preliminary findings.

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)     

Advances in research with sexual minority people: Introduction to the special issue.

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)     

Renewable rural electrification: Sustainability assessment of mini-hybrid off-grid technological systems in the African context

The investigation summarised in this paper applied a sustainability assessment methodology on a renewable energy technological system in a rural village project that was commissioned by the South African Department of Minerals and Energy. The project comprised of wind, solar and lead-acid battery energy storage technologies that were implemented as a mini-hybrid off-grid electrification system for the village. The sustainability assessment methodology predicts the outcomes of such interventions by way of a learning model using discipline experts in the fields of economics, sociology, ecosystem sustainability, institutional governance, and the physics and chemistry of energy conversion processes. The comparison of the project's outcomes with a South African sustainable development framework shows that the specific village renewable off-grid electrification system is not viable. The main reason is that charges for electricity supply costs in village grids are too high for available subsidies; the economies of scale for renewable energy supply technologies favour national grids. The failure of the integrated system may also be attributable to the complexity of the social-institutional sub-system, which resulted in uncertainty for project planners and system designers, and the lack of resilience of the technological system to demands from the socio-economic and institutional sub-systems. Policy-related recommendations are made accordingly.