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In recent years, additive manufacturing (AM) has begun to displace traditional manufacturing techniques for specific applications. Notable benefits of AM include reduced times from design to product, an improved buy-tofly [...]

Research on the additive manufacturing of metals often neglects any characterization of the composition of final parts, erroneously assuming a compositional homogeneity that matches the feedstock material. Here, the composition of electron-beam-melted Ti-6Al-4V produced through three distinct scanning strategies (linear raster and two point melting strategies, random fill and Dehoff fill) is characterized both locally and globally through energy-dispersive spectroscopy and quantitative chemical analysis. As a result of the different scanning strategies used, differing levels of preferential vaporization occur across the various parts, leading to distinct final compositions, with extremes of ~5.8 wt.% Al and ~4.8 wt.% Al. In addition, energy-dispersive spectroscopy composition maps reveal specific features in both the XY and XZ planes (with Z being the build direction) as a result of local inhomogeneous preferential vaporization. The subsequent change in composition significantly modifies the materials' state of parts, wherein parts and local regions with higher aluminum contents lead to higher hardness levels (with a ~50 HV difference) and elastic property values and vice versa. While varying scan strategies and scan parameters are known to modify the microstructure and properties of a part, the effect on composition cannot, and should not, be neglected. [ABSTRACT FROM AUTHOR]

Defects in parts produced by additive manufacturing, instead of simply being perceived as deleterious, can act as important sources of information associated with the complex physical processes that occur during materials deposition and subsequent thermal cycles. Indeed, they act as materials-state 'fossil' records of the dynamic AM process. The approach of using defects as epoch-like records of prior history has been developed while studying additively manufactured Ti–6Al–4V and has given new insights into processes that may otherwise remain either obscured or unquantified. Analogous to 'epochs,' the evolution of these defects often is characterized by physics that span across a temporal length scale. To demonstrate this approach, a broad range of analyses including optical and electron microscopy, X-ray computed tomography, energy-dispersive spectroscopy, and electron backscatter diffraction have been used to characterize a raster-scanned electron beam Ti–6Al–4V sample. These analysis techniques provide key characteristics of defects such as their morphology, location within the part, complex compositional fields interacting with the defects, and structures on the free surfaces of defects. Observed defects have been classified as banding, spherical porosity, and lack of fusion. Banding is directly related to preferential evaporation of Al, which has an influence on mechanical properties. Lack-of-fusion defects can be used to understand columnar grain growth, fluid flow of melt pools, humping, and spattering events. [ABSTRACT FROM AUTHOR]

A study was conducted to establish whether positive affect is associated with longevity and other positive health outcomes and positive psychosocial processes and vice versa. Results indicated that positive and negative affective states are associated with health-related psychosocial factors but positive affect may be beneficial for health as a protective portfolio of psychological and social characteristics.

Objective: The objective of this study was to determine whether the nonlinear association between alcohol and depressive symptoms observed in middle-aged and older men and women is present in young adults and is independent of culture, socioeconomic position, and health status. Method: Data were from the International Health and Behaviour Survey, involving 6,932 male and 8,816 female university students ages 17-30 years from 20 countries. Alcohol consumption was assessed in terms of number of drinks per week and number of drinks per episode, and the Beck Depression Inventory (BDI) was administered. Analyses were adjusted for clustering by country. Results: The proportion of respondents with elevated BDI scores was 19.3%, 16.3%, and 20.0% for nondrinkers, moderate drinkers, and heavy drinkers, respectively. The odds of elevated BDI scores for nondrinkers compared with moderate drinkers were 1.22 (95% confidence interval [CI]: 1.06-1.42) after adjusting for age, gender, living arrangements, socioeconomic status, and self-rated health. Analysis based on the number of alcoholic drinks consumed in the past 2 weeks indicated that, in comparison with those who consumed 5-13 drinks, the odds of elevated BDI scores for nondrinkers were 1.25 (CI: 1.02-1.53) after adjusting for the same covariates. Heavy drinkers also had higher BDI scores than moderate consumers. Conclusions: The results suggest that the 'U'-shaped association between alcohol consumption and depressive symptoms previously identified in Western countries is present in young people from a variety of cultural backgrounds. The relationship is not secondary to variations in health status, socioeconomic background, age, and gender., THERE IS SUBSTANTIAL EVIDENCE that high alcohol consumption is associated with depression and psychological distress (Regier et al., 1990). But in recent years, evidence has emerged to suggest that the [...]

Aims: Psychosocial stress is a risk factor for coronary heart disease (CHD), although the mechanisms are incompletely understood. We examined the cross-sectional association between the cortisol response to laboratory-induced mental stress and a marker of sub-clinical coronary atherosclerosis. [ABSTRACT FROM PUBLISHER]

The article assesses the preservice teacher education program at Teachers College of Columbia University in the U.S. Significantly, a distinction is made between the teacher as an interactor and the teacher as an institutional builder. Visualizing the teacher as an interactor is thinking of him counseling and teaching a group of children while visualizing the teacher as an institution-builder is thinking of him as an innovator. Furthermore, training teachers to be institution-builders is of prime importance. The competencies of the teacher as an institution-builder would include abilities: (1) to plan and implement the social system of the school; (2) to plan and organize utilization of technical support centers within school settings; and (3) to plan and implement the curricular system. The teachers are introduced to four major methods of creating an educational environment, categorized in terms of models of teaching developed from theoretical sources: (1) social interaction sources; (2) information-processing sources; (3) personal sources; and (4) behavior modification as a source.