Prediction of Microstructure in Laser Deposition of Titanium Alloys

Laser deposition of titanium alloys is under consideration for aerospace applications, and offers significant increases in efficiency and flexibility compared to conventional manufacturing methods. However, its ultimate success will depend on the ability to predict and control the microstructure and resulting mechanical properties of the deposit. In this study, both 2-D continuum finite element modeling and 3-D cellular automaton finite element modeling of a thinwall geometry are used to investigate the effects of deposition process variables on microstructure in laser deposited Ti-6Al-4V. Numerical results for cooling rate and thermal gradient obtained from the 2-D models are used to provide insight into grain size and morphology, while the 3-D cellular automaton models are used to provide direct predictions of deposited microstructure. The numerical model predictions are subsequently compared with observed microstructures in LENSTM deposited Ti-6Al-4V.This work was supported by the Joint AFRL/DAGSI Research Program, project number ML-WSU-01-11, as well as by a grant from Wright State University and the Ohio Board of Regents.Mechanical Engineerin

Geochemical Data on Waters, gases, scales, and rocks from the Dixie Valley Region, Nevada (1996-1999)

This report tabulates an extensive geochemical database on waters, gases, scales, rocks, and hot-spring deposits from the Dixie Valley region, Nevada. The samples from which the data were obtained were collected and analyzed during 1996 to 1999. These data provide useful information for ongoing and future investigations on geothermal energy, volcanism, ore deposits, environmental issues, and groundwater quality in this region

What lies beneath: predicting seagrass below-ground biomass from above-ground biomass, environmental conditions and seagrass community composition

Seagrass condition, resilience and ecosystem services are affected by the below-ground tissues (BGr) but these are rarely monitored. In this study we compiled historical data across northern Australia to investigate biomass allocation strategies in 13 tropical seagrass species. There was sufficient data to undertake statistical analysis for five species: Cymodocea serrulata, Halophila mutts, Halodule uninervis, Thalassia hemprichii, and Zostera muelleri. The response of below-ground biomass (BGr) to above-ground biomass (AGr) and other environmental and seagrass community composition predictor variables were assessed using Generalized Linear Models. Environmental data included: region, season, sediment type, water depth, proximity to land-based sources of pollution, and a light stress index. Seagrass community data included: species diversity and dominant species class (colonising, opportunistic or persistant) based on biomass. The predictor variables explained 84-97% of variance in BGr on the log-scale depending on the species. Multi-species meadows showed a greater investment into BGr than mono-specific meadows and when dominated by opportunistic or persistent seagrass species. This greater investment into BGr is likely to enhance their resistance to disturbances if carbohydrate storage reserves also increase with biomass. Region was very important for the estimation of BGr from AGr in four species (not in C. serrulata). No temporally changing environmental features were included in the models, therefore, they cannot be used to predict local-scale responses of BGr to environmental change. We used a case study for Cairns Harbour to predict BGr by applying the models to AGr measured at 362 sites in 2017. This case study demonstrates how the model can be used to estimate BGr when only AGr is measured. However, the general approach can be applied broadly with suitable calibration data for model development providing a more complete assessment of seagrass resources and their potential to provide ecosystem services

What influences practitioners’ readiness to deliver psychological interventions by telephone? A qualitative study of behaviour change using the Theoretical Domains Framework

Background Contemporary health policy is shifting towards remotely delivered care. A growing need to provide effective and accessible services, with maximal population reach has stimulated demand for flexible and efficient service models. The implementation of evidence-based practice has been slow, leaving many services ill equipped to respond to requests for non-face-to-face delivery. To address this translation gap, and provide empirically derived evidence to support large-scale practice change, our study aimed to explore practitioners’ perspectives of the factors that enhance the delivery of a NICE-recommended psychological intervention, i.e. guided self-help by telephone (GSH-T), in routine care. We used the Theoretical Domains Framework (TDF) to analyse our data, identify essential behaviour change processes and encourage the successful implementation of remote working in clinical practice. Method Thirty-four psychological wellbeing practitioners (PWPs) from the UK NHS Improving Access to Psychological Therapies (IAPT) services were interviewed. Data were first analysed inductively, with codes cross-matched deductively to the TDF. Results Analysis identified barriers to the delivery, engagement and implementation of GSH-T, within eight domains from the TDF: (i) Deficits in practitioner knowledge, (ii) Sub-optimal practitioner telephone skills, (iii) Practitioners’ lack of beliefs in telephone capabilities and self-confidence, (iv) Practitioners’ negative beliefs about consequences, (v) Negative emotions, (vi) Professional role expectations (vii) Negative social influences, and (viii) Challenges in the environmental context and resources. A degree of interdependence was observed between the TDF domains, such that improvements in one domain were often reported to confer secondary advantages in another. Conclusions Multiple TDF domains emerge as relevant to improve delivery of GSH-T; and these domains are theoretically and practically interlinked. A multicomponent approach is recommended to facilitate the shift from in-person to telephone-based service delivery models, and prompt behaviour change at practitioner, patient and service levels. At a minimum, the development of practitioners’ telephone skills, an increase in clients’ awareness of telephone-based treatment, dilution of negative preconceptions about telephone treatment, and robust service level guidance and standards for implementation are required. This is the first study that provides clear direction on how to improve telephone delivery and optimise implementation, aligning with current mental health policy and service improvement

Optimization of inhomogeneous electron correlation factors in periodic solids

A method is presented for the optimization of one-body and inhomogeneous two-body terms in correlated electronic wave functions of Jastrow-Slater type. The most general form of inhomogeneous correlation term which is compatible with crystal symmetry is used and the energy is minimized with respect to all parameters using a rapidly convergent iterative approach, based on Monte Carlo sampling of the energy and fitting energy fluctuations. The energy minimization is performed exactly within statistical sampling error for the energy derivatives and the resulting one- and two-body terms of the wave function are found to be well-determined. The largest calculations performed require the optimization of over 3000 parameters. The inhomogeneous two-electron correlation terms are calculated for diamond and rhombohedral graphite. The optimal terms in diamond are found to be approximately homogeneous and isotropic over all ranges of electron separation, but exhibit some inhomogeneity at short- and intermediate-range, whereas those in graphite are found to be homogeneous at short-range, but inhomogeneous and anisotropic at intermediate- and long-range electron separation.Comment: 23 pages, 15 figures, 1 table, REVTeX4, submitted to PR

A Review of Controlling Motivational Strategies from a Self-Determination Theory Perspective: Implications for Sports Coaches

The aim of this paper is to present a preliminary taxonomy of six controlling strategies, primarily based on the parental and educational literatures, which we believe are employed by coaches in sport contexts. Research in the sport and physical education literature has primarily focused on coaches’ autonomysupportive behaviours. Surprisingly, there has been very little research on the use of controlling strategies. A brief overview of the research which delineates each proposed strategy is presented, as are examples of the potential manifestation of the behaviours associated with each strategy in the context of sports coaching. In line with self-determination theory (Deci & Ryan, 1985; Ryan & Deci, 2002), we propose that coach behaviours employed to pressure or control athletes have the potential to thwart athletes’ feelings of autonomy, competence,and relatedness, which, in turn, undermine athletes’ self-determined motivation and contribute to the development of controlled motives. When athletes feel pressured to behave in a certain way, a variety of negative consequences are expected to ensue which are to the detriment of the athletes’ well-being. The purpose of this paper is to raise awareness and interest in the darker side of sport participation and to offer suggestions for future research in this area

Dimensional accuracy of Electron Beam Melting (EBM) additive manufacture with regard to weight optimized truss structures

The Electron Beam (EBM) additive manufacturing process is well suited to fabricating complex structural designs in Ti–6Al–4V because of the design freedoms it offers combined with strong and consistent material properties. However it has been observed that complications may arise when manufacturing truss-like structures (such as those produced via structural topology optimization) in the form of undersized features on the finished part. The issue appears to affect truss members that are not aligned with the vertical build direction, with an apparent lack of material on the negative surfaces. This effect appears to worsen with a greater angle between the truss member and the build direction, even with the use of support structures. This investigation has characterized and measured the dimensional errors that result from this issue through 3D scanning techniques. Process modifications have then been made which result in significant improvements in dimensional accuracy. This investigation highlights the importance of heat management at features with negative surfaces to yield parts that are dimensionally accurate without introducing excessive internal melt defects in the form of voids and porosity

Association of Plasma Lipids and Polar Metabolites with Low Bone Mineral Density in Singaporean-Chinese Menopausal Women: A Pilot Study.

The diagnosis of osteoporosis is mainly based on clinical examination and bone mineral density assessments. The present pilot study compares the plasma lipid and polar metabolite profiles in blood plasma of 95 Singaporean-Chinese (SC) menopausal women with normal and low bone mineral density (BMD) using an untargeted metabolomic approach. The primary finding of this study was the association between lipids and femoral neck BMD in SC menopausal women. Twelve lipids were identified to be associated with low BMD by the orthogonal partial least squares (OPLS) model. Plasma concentrations of eight glycerophospholipid, glycerolipid, and sphingolipid species were significantly lower in menopausal women with low BMD but higher in two glycerophospholipid species (phosphatidylinositol and phosphatidic acid). Further, this study found no significant differences in plasma amino acid metabolites. However, trends for lower 4-aminobutyric acid, turanose, proline, aminopropionitrile, threonine, and methionine were found in women with low BMD. This pilot study identified associations between lipid metabolism and femoral neck BMD in SC women. Further studies are required on larger populations for evaluating the bone health effect of these compounds and their usefulness as clinical biomarkers for osteoporosis prediction in women

Effect of tensor couplings in a relativistic Hartree approach for finite nuclei

The relativistic Hartree approach describing the bound states of both nucleons and anti-nucleons in finite nuclei has been extended to include tensor couplings for the $\omega$- and $\rho$-meson. After readjusting the parameters of the model to the properties of spherical nuclei, the effect of tensor-coupling terms rises the spin-orbit force by a factor of 2, while a large effective nucleon mass $m^{*}/M_{N} \approx 0.8$ sustains. The overall nucleon spectra of shell-model states are improved evidently. The predicted anti-nucleon spectra in the vacuum are deepened about 20 -- 30 MeV.Comment: 31 pages, 4 postscript figures include