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During the powder bed fusion additive manufacturing (AM) process, hundreds of grains may solidify simultaneously within the melt pool, depending upon the processing conditions and the grain size of the base plate and powder. Thus, a small variation in the shape of the melt pool or scan strategy may result in very different as-printed microstructures, since new grains may become more favourably aligned with the overall direction of growth. The microstructure affects the performance of the additively built component, and it is therefore critical to understand the interplay between the initial microstructure, material properties, heat source, and scan strategy on determining the as-printed microstructure. We examine columnar grain growth during AM using a phase-field model to perform simulations with single melt pools predicted by the cylindrically symmetric Rosenthal solution. Quantitative measures of the competitive grain growth are extracted from the simulation data. To aid in their understanding, we map these quantities onto visualizations of the microstructure and compare them to the inverse pole figure map, from which we find that the crystallographic directions of the grains that grow closest to the centre of the laser track may not be preferentially aligned with the scan direction.

Mineral compositions are used to infer pressures, temperatures, and timescales of geological processes. The thermodynamic techniques underlying these inferences assume a uniform, constant pressure. Nonetheless, convergent margins generate significant non‐hydrostatic (unequal) stresses, violating the uniform pressure assumption and creating uncertainty. Materials scientists F. Larché and J. Cahn derived an equation suitable for non‐hydrostatically stressed geologic environments that links stress and equilibrium composition in elastic, multi‐component crystals. However, previous works have shown that for binary solid solutions with ideal mixing behavior, hundreds of MPa to GPa‐level stresses are required to shift mineral compositions by a few hundredths of a mole fraction, limiting the equation's applicability. Here, we apply Larché and Cahn's equation to garnet, clinopyroxene, and plagioclase solid solutions, incorporating for the first time non‐ideal mixing behavior and more than two endmembers. We show that non‐ideal mixing increases predicted stress‐induced composition changes by up to an order of magnitude. Further, incorporating additional solid solution endmembers changes the predicted stress‐induced composition shifts of the other endmembers being considered. Finally, we demonstrate that Larché and Cahn's approach yields positive entropy production, a requirement for any real process to occur. Our findings reveal that stresses between tens and a few hundred MPa can shift mineral compositions by several hundredths of a mole fraction. Consequently, mineral compositions could plausibly be used to infer stress states. We suggest that stress‐composition effects could develop via intracrystalline diffusion in any high‐grade metamorphic setting, but are most likely in hot, dry, and strong rocks such as lower crustal granulites. The chemical compositions of many minerals found in rocks are sensitive to the pressure and temperature conditions at which the minerals form. Thus, we can use mineral compositions to deduce the formation conditions of rocks, giving us insights into important geological processes such as the global carbon cycle and continent formation. The techniques we use to determine these conditions assume that pressure is equal in all directions. However, minerals sometimes form in settings where there is significantly more pressure, or stress, in one direction than another due to, for example, colliding tectonic plates. As a result, there is uncertainty as to how to interpret the compositions of such minerals. In this work, we apply a theory developed by materials scientists that provides a way to quantify the expected compositions of different types of minerals based on the directions and magnitudes of stresses. This approach will enable us to use mineral compositions to learn more about the pressure and stress conditions in important geological settings such as within subduction zones and mountain belts. Non‐ideal mixing increases stress‐induced composition changes in minerals by up to an order of magnitude compared to ideal mixingAll pertinent solid solution endmembers should be considered to determine how stress changes affect the composition of each endmemberStress‐induced composition effects are likely to develop in hot, dry rocks comprising strong minerals such as lower crustal granulites Non‐ideal mixing increases stress‐induced composition changes in minerals by up to an order of magnitude compared to ideal mixing All pertinent solid solution endmembers should be considered to determine how stress changes affect the composition of each endmember Stress‐induced composition effects are likely to develop in hot, dry rocks comprising strong minerals such as lower crustal granulites

Porous La1-xSrxCoO3-d (LSC) electrodes with Sr composition x = 0.2 (LSC-82) and x = 0.4 (LSC-64) were prepared by screenprinting LSC powders onto rare-earth doped ceria electrolytes, followed by sintering at 950 [?] 1100degC, and characterization using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface-area analysis, 3-D morphological imaging based on focused ion beam scanning electron microscopy (FIB-SEM), and energy dispersion X-ray spectroscopy (EDX/EDS). The batch-to-batch variability and degradation (over 1000 [?] 2000 hours) of the electrochemical performance of these cells were studied using electrochemical impedance spectroscopy (EIS) and measurements of nonlinear electrochemical impedance (NLEIS). These measurements reveal a strong correlation between the characteristic frequency (oc) and characteristic resistance (Rc) of the electrodes, which, when analyzed in light of microstructural data, indicates that performance variability and degradation are caused primarily by variations in the surface rate coefficient k(T) for O2 exchange.

AbstractBackground:There is a dearth of information on the compatibility of Western-developed, internet-based interventions that prevent onset and precipitation of depression in global settings. Recently, Project CATCH-IT (Competent Adulthood Transition with Cognitive-behavioral, Humanistic and Interpersonal Training), an information technology-based intervention, was adapted to prevent depression in Hong Kong Chinese adolescents. This paper evaluates qualitative data from consultations to develop a revised intervention of CATCH-IT for Hong Kong youth.Methods:A theoretical thematic analysis approach was used to analyze data. Materials from three consultation trips which included focus groups (2007), an expert panel (2007), a public health campaign (2009), and a joint primary care physician-social worker review group (2010) were compiled. Authors (KS and AZ) independently reviewed the data and applied the theoretical framework of behavioral vaccines to code the data. These data were subsequently consolidated to provide a coherent narrative analysis.Results:The cognitive behavioral therapy (CBT), behavioral activation (BA), and resiliency modules were maintained, while the interpersonal therapy (IPT) modules of CATCH-IT were excluded in the Hong Kong adaptation. Concurrent self-reports of drinking, smoking, illicit drug use and gambling behavior were added. Rather than primary care consultations, social worker consultations may be the best point of entry for intervention.Conclusion:Socio-cultural relevance of psychotherapeutics and delivery context of internet-based interventions will require significant adaptation for the Hong Kong setting. However, because of community engagement throughout the process of adaptation, we believe the CATCH-IT intervention can be adapted for Chinese adolescents in Hong Kong with retained fidelity. The revised intervention is called “Grasp the Opportunity”.

It has been reported that running a Solid Oxide Electrolysis Cell above a critical current degrades the cell very quickly. This degradation has been linked to oxygen bubble formation in the electrolyte near the oxygen electrode. The applied current in the presence of charge transfer resistances is responsible for a high oxygen potential under the oxygen electrode which translates into a large driving force for the formation of oxygen gas in the electrolyte and can lead to the nucleation of oxygen gas bubbles. When such a bubble nucleates, local equilibrium at the interface between the bubble and oxide leads to an extremely high pressure inside it introducing, in return, significant stresses in the oxide. In this paper, the stress field surrounding the oxygen bubbles in the electrolyte is treated and the resulting elastic energy is determined.

A phase field model to study the microstructural evolution of a polycrystalline dual-phase material with conserved phase fraction has been implemented, and 2D simulations have been performed. For 2D simulations, the model predicts the cubic growth well-known for diffusion-controlled systems. Some interphase boundaries are found to show a persistent non-constant curvature, which seems to be a feature of multi-phase materials. Finally, it is briefly outlined how this model is to be applied to investigate microstructural evolution in duplex steel.

Although intervention tailoring could lower the burden of adolescent depression, few studies have examined differences in vulnerability factors between African American and European American youth.

College students were exposed by means of headphones to two kinds of aircraft noise (helicopter and jet) at three levels of loudness (60, 70, and 80 dB) while engaging in two tests of intelligibility and 12 cognitive tasks. In addition, the annoyingness of the noise was rated on a seven-point scale for each source/loudness combination in each task. Individual-differences measures (embedded figures, locus-of-control, and test anxiety) were also obtained. No performance difference related to noise was obtained in any of the cognitive tasks, and using the individual-difference measures as co-variates made no difference. In a second experiment a limited set of five modified cognitive tasks was used, again without producing any significant results. Finally, a third experiment utilized four cognitive tasks, a perceptual-motor task (Rotary Tracking) and intermittent rather than continuous noise, and yielded the same results. It was concluded that the failure to find performance differences on the cognitive tasks was probably due to the fact that concern for the welfare of the subjects limited the stimuli to loudness levels that were too low to be effective.

Self-esteem and death anxiety instruments were administered to a total of 383 undergraduates; black and white, males and females were included in the sample. Consistent with previous data, higher scores on death anxiety were shown by female subjects. Black males displayed significantly higher self-esteem scores. An analysis of subgroups low and high in self-esteem produced support for a negative relationship between level of self-esteem and death anxiety.

The article provides information on the similarity of training and background in the college-bred person of African American and White colleges. The fundamental problem in the African American college and the White college is to provide the student with enough variety of experiences in the different Speech Arts to develop Speech Skills. African American colleges have received A and B ratings in class colleges by similar accrediting agency with the same rates of the White colleges.