Study of growth of single crystal ribbon in space

The technical feasibility is studied of growing single-crystal silicon ribbon in the space environment. Procedures are described for calculating the electromagnetic fields produced in a silicon ribbon by an rf shaping coil. The forces on the ribbon and the degree of shaping to be expected are determined. The expected steady-state temperature distribution in the ribbon is calculated in the one-dimensional approximation. Calculations on simplified models indicate, that lack of flatness of the shaped ribbon and excessive heating of the melt by the eddy currents induced by the shaping fields may pose problems. An analysis of the relative effects of various kinds of forces other than electromagnetic showed that in the space environment capillarity forces would dominate, and that the shape of the melt is thus principally determined by the shape of any solids with which it comes in contact. This suggests that ribbon may be produced simply by drawing between parallel wires. A concept is developed for a process of off-angle growth, in which the ribbon is pulled at an angle to the solidification front. Such a process promises to offer increased growth rate, better homogeneity, and thinner ribbon

Storage and Release of Soluble Hexavalent Chromium from Chromate Conversion Coatings on Al Alloys Kinetics of Release

The release of chromate ions from chromate conversion coatings (CCCs) on Al alloys was studied, and the effect of aging of CCCs on the chromate release kinetics was investigated. Chromate release from CCCs into aqueous solutions was monitored by measuring the change in the chromate concentration in solution using UV-visible spectroscopy. Heat-treatment of the CCC greatly reduced the chromate release rate. The chromate release rate also decreased with increasing aging time at room temperature. A diffusion-control model was proposed based on the notion that the CCC in an aqueous solution is a porous, two-phase structure consisting of a solid phase with adsorbed Cr(VI) species that is in local Langmuir-type equilibrium with an interpenetrating solution phase. This model results in a concentration gradient of soluble Cr(VI) in the solution phase of the CCC as chromate is released. The concentration and diffusion coefficients of soluble Cr(VI) in CCC were estimated. The estimated diffusion coefficient tended to decrease with aging time, suggesting that the CCC is modified with aging time.This work was supported under Air Force Office of Scientific Research Multidisciplinary University Research Initiative contract no. F49620-96-1-0479

Novel n-3 Docosapentaneoic Acid-Derived Pro-resolving Mediators Are Vasculoprotective and Mediate the Actions of Statins in Controlling Inflammation

“This is a post-peer-review, pre-copyedit version of a chapter published in Advances in Experimental Medicine and Biology book series (AEMB, volume 1161). The final publication is available athttps://doi.org/10.1007/978-3-030-21735-8_7

Primary specialisation in Australian education:Pre-service teachers’ lived experiences

The positioning of teacher quality as a global problem in primary education has led to the introduction of primary specialisation in Australian teacher education programs. In this chapter, we adapt Ball, Braun, and Maguire’s (2012) theorisations around policy enactment and Clandinin and Connelly’s (2000) narrative inquiry space as an innovative approach to make visible five Master of Teaching (Primary) pre-service teachers’ experiences as they complete a new science specialisation. In doing so we give voice to these participants as policy receivers who are rarely heard in the policy process. Findings reveal fourteen themes around the material, interpretive, and discursive facets of primary specialisation policy enactment. A number of challenges are described that contest the primary specialisation in its current form and recommendations are suggested for moving the policy agenda forward