Mechanical behaviour versus structure of Al 63.6 Cu 24.0 Fe 12.4

A series of polyquasicrystalline ingots with the nominal composition Al 63.6 Cu 24.0 Fe 12.4 has been prepared by conventional drop casting and subsequent annealing at 1088K for 24h. Compression specimens prepared from the different ingots have been deformed at temperatures ranging from 750 to 1050K. The details of the structure and microstructure of the as-cast, annealed and deformed materials have been investigated by optical, scanning and transmission electron microscopy. Whatever their initial structure (i.e. pure icosahedral, modulated or relevant to approximant phases) and their defect microstructure (dislocations and crystalline platelets), all the specimens, which have been compression tested, exhibit similar mechanical behaviours.     

A combination of Al diffusion and surface nanocrystallization of carbon steel for enhanced corrosion resistance

Surface nanocrystallization is beneficial to the corrosion resistance of passive alloys, but generally has a negative effect on the corrosion behavior of non-passive alloys due to the enhanced surface reactivity. In this study, a combination of Al diffusion treatment and surface nanocrystallization was applied to carbon steel with the aim of exploring an alternative approach to improve the corrosion resistance of non-passive carbon steel. The surface nanocrystallization was achieved by sandblasting and subsequent recovery treatment. The former resulted in severe plastic deformation, while the latter turned high-density dislocation cells into nano-sized grains. The present study demonstrates that the combined Al diffusion and nanocrystallization generated a nanocrystalline Al-containing surface layer on the carbon steel with its surface grain diameter in the range of 10–300 nm. The corrosion resistance of the treated steel was evaluated. It is demonstrated that treated specimens possess increased resistance to corrosion with higher surface electron stability. Surface microstructure of the treated specimens was examined using SEM, AFM, and EDS in order to elucidate the mechanism responsible for the improved corrosion resistance.     

A structural model for surface-enhanced stabilization in some metallic glass formers

A structural model for surface-enhanced stabilization in some metallic glass formers is proposed. In this model, the alloy surface structure is represented by five-layer Kagomé-net-based lateral ordering. Such surface structure has intrinsic abilities to stabilize icosahedral-like short-range order in the bulk, acting as ‘a cloak of liquidity’. In particular, recent experimental observations of surface-induced lateral ordering and a very high glass forming ability of the liquid alloy Au₄₉Ag_5.5Pd_2.3Cu_26.9Si_16.3 can be united using this structural model. This model may be useful for the interpretation of surface structure of other liquid alloys with a high glass forming ability. In addition, it suggests the possibility of guiding the design of the surface coating of solid containers for the stabilization of undercooled liquids.     

Surface tension of substantially undercooled liquid Ti–Al alloy

It is usually difficult to undercool Ti–Al alloys on account of their high reactivity in the liquid state. This results in a serious scarcity of information on their thermophysical properties in the metastable state. Here, we report on the surface tension of a liquid Ti–Al alloy under high undercooling condition. By using the electromagnetic levitation technique, a maximum undercooling of 324 K (0.19 T _L) was achieved for liquid Ti-51 at.% Al alloy. The surface tension of this alloy, which was determined over a broad temperature range 1429–2040 K, increases linearly with the enhancement of undercooling. The experimental value of the surface tension at the liquidus temperature of 1753 K is 1.094 N m^?1 and its temperature coefficient is ?1.422 × 10^?4 N m^?1 K^?1. The viscosity, solute diffusion coefficient and Marangoni number of this liquid Ti–Al alloy are also derived from the measured surface tension.     

Change management: Time for a change!

We discuss some core issues in the field of change management. We use these topics to identify some mindsets that dominate the practice of change management, and argue that these should be replaced by some alternatives. The alternatives are drawn largely from operations management and sociotechnical thinking. We characterize existing approaches as partial, and speculate that this may be one of the reasons why so many change initiatives are ineffective at meeting their goals. We identify some of the reasons why existing mindsets are sustained. We also point to some ways forward, focusing on changes in the mindsets and language we use. We speculate that these would improve the effectiveness of change initiatives.     

Approaches to learning by pre-service science students of an institution of higher learning: an exploratory study

This case study explored pre-service science students’ approaches to studying and learning. The participants were 65 undergraduate students (females?=?47%; age range 18 to 25 years) at a university of technology in South Africa. Students’ preferences for deep or surface learning were evaluated using the Revised Two-Factor Study Process Questionnaire (Biggs, Kember & Leung, 2001 Biggs, J.B., Kember, D., & Leung, D.Y.P. (2001). The Revised Two Factor Study Process Questionnaire: R-SPQ-2F. British Journal of Educational Psychology. 71, 133–149 doi: 10.1348/000709901158433[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Data were analysed to contrast learning motive and strategy by year of university placement. The difference in the use of deep as compared to surface motives was higher among students with senior level placement (third years) than their peers with junior placement (second years). Deep motives may be more serviceable with the more rigorous learning expected with senior level education placement.     

Language deficits in pre-symptomatic Huntington's disease: evidence from Hungarian

A limited number of studies have investigated language in Huntington’s disease (HD). These have generally reported abnormalities in rule-governed (grammatical) aspects of language, in both syntax and morphology. Several studies of verbal inflectional morphology in English and French have reported evidence of over-active rule processing, such as over-suffixation errors (e.g., walkeded) and over-regularizations (e.g., digged). Here we extend the investigation to noun inflection in Hungarian, a Finno-Ugric agglutinative language with complex morphology, and to genetically proven pre-symptomatic Huntington’s disease (pre-HD). Although individuals with pre-HD have no clinical, motor or cognitive symptoms, the underlying pathology may already have begun, and thus sensitive behavioral measures might reveal already-present impairments. Indeed, in a Hungarian morphology production task, pre-HD patients made both over-suffixation and over-regularization errors. The findings suggest the generality of over-active rule processing in both HD and pre-HD, across languages from different families with different morphological systems, and for both verbal and noun inflection. Because the neuropathology in pre-HD appears to be largely restricted to the caudate nucleus and related structures, the findings further implicate these structures in language, and in rule-processing in particular. Finally, the need for effective treatments in HD, which will likely depend in part on the ability to sensitively measure early changes in the disease, suggests the possibility that inflectional morphology, and perhaps other language measures, may provide useful diagnostic, tracking, and therapeutic tools for assessing and treating early degeneration in pre-HD and HD.     

Effects of surface pre-presentation on symmetry detection on a 3-D bumpy surface

Abstract:  The aim of this study was to investigate the visual detection mechanism of mirror symmetrical dot patterns drawn on a 3-D bumpy surface (i.e., 3-D noisy curved surface). The focus of this investigation was whether symmetry detection on the bumpy surface is associated with structure recovery of the surface. In Experiment 1, we confirmed that the human visual system can distinguish the bumpy surface from a distorted dot pattern on a transparent bumpy surface. In Experiment 2, we required participants to discriminate between a symmetrical pattern on a transparent (non-visible) bumpy surface and an opaque (visible) bumpy surface for the same stimuli as in Experiment 1. Finally, in Experiment 3, we examined the effect of pre-presentation of the opaque bumpy surface on pattern discrimination. The results showed that pre-presentation of the opaque surface facilitated the detection of a diagonal symmetry, but not in the case of the detection of a cardinal symmetry. These results suggested that diagonal symmetry involves the process of surface recovery, whereas cardinal symmetry does not.     

Knowing that strawberries are red and seeing red strawberries: the interaction between surface colour and colour knowledge information

This study investigates the interaction between surface and colour knowledge information during object recognition. In two different experiments, participants were instructed to decide whether two presented stimuli belonged to the same object identity. On the non-matching trials, we manipulated the shape and colour knowledge information activated by the two stimuli by creating four different stimulus pairs: (1) similar in shape and colour (e.g. TOMATO–APPLE); (2) similar in shape and dissimilar in colour (e.g. TOMATO–COCONUT); (3) dissimilar in shape and similar in colour (e.g. TOMATO–CHILI PEPPER) and (4) dissimilar in both shape and colour (e.g. TOMATO–PEANUT). The object pictures were presented in typical and atypical colours and also in black-and-white. The interaction between surface and colour knowledge showed to be contingent upon shape information: while colour knowledge is more important for recognising structurally similar shaped objects, surface colour is more prominent for recognising structurally dissimilar shaped objects.