Micro and Nano-structure Development and Multiscale Physics at Sliding Metal Interfaces

This final report describes research on the response of ductile materials to extreme loading conditions and high strain rates during impact combined with sliding friction. The work has involved a collaboration among two groups at Los Alamos National Laboratory and a tribology research grouup at The Ohio State University. The project involved experimental work and computer simulations at both laboratories and continuum mechanics analysis at OSU, supplemented by testing at AWE, Harwell, UK. Results demonstrated the importance of vorticity and mechanical mixing near the sliding interface in the development of nanocrystalline tribomaterial that is far from equilibrium. The work also revealed that strain rate sensitivity is an important materials property for determining the development of the velocity profile during sliding. As such, it is a property that is key to understanding the evolution of sliding behavior

Review essay: Anthony Howe. Byron and the Forms of Thought (Liverpool: Liverpool UP, 2013) and Carla Pomare. Byron and the Discourse of History (Farnham and Burlington: Ashgate, 2013).

This essay is a comparative review of two recently published books in Byron studies: Anthony Howe's Byron and the Forms of Thought (Liverpool: Liverpool UP, 2013) and Carla Pomare's Byron and the Discourse of History (Farnham and Burlington: Ashgate, 2013)

Barriers and facilitators for health professionals referring Aboriginal and Torres Strait Islander tobacco smokers to the Quitline

Objective: To examine the barriers and facilitators among health professionals to providing referrals to Quitline for Aboriginal and Torres Strait Islander clients who smoke. Methods: A brief online survey, based on the Theoretical Domains Framework, was completed by 34 health professionals who work with Aboriginal and Torres Strait Islander people in South Australia and the Northern Territory. Results: Respondents who frequently made referrals had higher domain scores than less frequent referrers for ‘Skills and knowledge’ (M=4.44 SD=0.39 vs. M=4.09 SD=0.47, p<0.05) and ‘beliefs about capabilities’ (M=4.33 SD=0.44 vs. M=3.88 SD=0.42, p<0.01). Barriers to providing referrals to Quitline were lack of client access to a phone, cost of a phone call, preference for face-to-face interventions, and low client motivation to quit. Conclusions: Health professionals working with Aboriginal and Torres Strait Islander clients should be supported to build their skills and confidence to provide referrals to Quitline and other brief cessation interventions. Building capacity for face-to-face support locally would be beneficial where phone support is not preferable. Implications for public health: Engaging with health professionals who work with Aboriginal and Torres Strait Islander people to increase referrals to Quitline is strategic as it builds on their existing capacity to provide cessation support.Kimberley Martin, Joanne Dono, Nathan Rigney, Joanne Rayner, Alana Sparrow, Caroline Miller, Andrea Mckivett, Kerin O'Dea, David Roder, Jacqueline Bowde

Measuring Information Transfer

An information theoretic measure is derived that quantifies the statistical coherence between systems evolving in time. The standard time delayed mutual information fails to distinguish information that is actually exchanged from shared information due to common history and input signals. In our new approach, these influences are excluded by appropriate conditioning of transition probabilities. The resulting transfer entropy is able to distinguish driving and responding elements and to detect asymmetry in the coupling of subsystems.Comment: 4 pages, 4 Figures, Revte

Variations in strain affect friction and microstructure evolution in copper under a reciprocating tribological load

The microstructure of the materials constituting a metallic frictional contact strongly influences tribological performance. Being able to tailor friction and wear is challenging due to the complex microstructure evolution associated with tribological loading. Here, we investigate the effect of the strain distribution on these processes. High-purity copper plates were morphologically surface textured with two parallel rectangles—referred to as membranes—over the entire sample length by micro-milling. By keeping the width of these membranes constant and only varying their height, reciprocating tribological loading against sapphire discs resulted in different elastic and plastic strains. Finite element simulations were carried out to evaluate the strain distribution in the membranes. It was found that the maximum elastic strain increases with decreasing membrane stiffness. The coefficient of friction decreases with increasing membrane aspect ratio. By analyzing the microstructure and local crystallographic orientation, we found that both show less change with decreasing membrane stiffness

Vibrational spectroscopy studies of the role of water in metal ion extraction into room temperature ionic liquids

In efforts to evaluate the suitability of ionic liquids (ILs) as solvents for the extraction of fission products, two series of room temperature ILs, one comprising a diakylimidazolium cation and the other containing an analogous (1-hydroxyalkyl)-functionalized imidazolium cation, have been prepared as their bis[(trifluoromethyl)sulfonyl]imide salts. The extraction of Sr(II) from aqueous nitric acid solutions by dicyclohexano-18-crown-6 into these ILs has been measured. A linear correlation has been observed between the extent of Sr(II) extraction and the equilibrium water content of the IL phases. Although a precedence has been established similarly with n-alcohol diluents, the relationship in extraction systems employing IL diluents has yet to be adequately studied.To investigate how water may be functioning in these biphasic systems, vibrational spectroscopy has been employed. A challenge to this analysis has been to differentiate between the vibrational modes of water and those of the of IL diluents. Raman spectroscopy offers the possibility to distinguish between -OH vibrational modes from solvent moieties and those in a different state, such as molecular water. Along with the near-IR and mid-IR ranges, Raman spectroscopy is being utilized the interrogate states of molecular water and other species that may be involved in metal ion partitioning. With the ultimate goal of elucidating the interactions between IL constituent ions, metal ion-crown ether complexes, co-extracted ions (e.g., nitrate) and water, these studies represent a principal step in gaining a better understanding of partitioning mechanisms in IL-based separation media

Webteaching: sequencing of subject matter in relation to prior knowledge of pupils

Two experiments are discussed in which the sequencing procedure of webteaching is compared with a linear sequence for the presentation of text material.\ud \ud In the first experiment variations in the level of prior knowledge of pupils were studied for their influence on the sequencing mode of text presentation. Prior knowledge greatly reduced the effect of the size of sequencing procedures.\ud \ud In the second experiment pupils with a low level of prior knowledge studied a text, following either a websequence or a linear sequence. Webteaching was superior to linear teaching on a number of dependent variables. It is concluded that webteaching is an effective sequencing procedure in those cases where substantial new learning is required

Isothermal and Cyclic Oxidation of an Air Plasma-Sprayed Thermal Barrier Coating System

Thermogravimetric methods for evaluating bond coat oxidation in plasma-sprayed thermal barrier coating (TBC) systems were assessed by high-temperature testing of TBC systems with air plasma-sprayed (APS) Ni-22Cr-10Al-1Y bond coatings and yttria-stabilized zirconia top coatings. High-mass thermogravimetric analysis (at 1150{sup degrees}C) was used to measure bond coat oxidation kinetics. Furnace cycling was used to evaluate APS TBC durability. This paper describes the experimental methods and relative oxidation kinetics of the various specimen types. Characterization of the APS TBCs and their reaction products is discussed