Microstructure,Element Distribution,and Mechanical Property of Cu9Ni6Sn Alloys by Conventional Casting and Twin-Roll Casting

Metallurgical and Materials Transactions A - Cu9Ni6Sn alloys were prepared by conventional casting (CC) and twin-roll casting (TRC). The CC-processed specimens possessed dendritic structures, and...     

Bank erosion in a macrotidal tropical river: Exploring the relative impact of boat wash on riverbank erosion

Macrotidal tropical rivers are dynamic systems where wet‐season floods and tidal flows cause significant riverbank erosion and sediment transport. This study aimed to explore patterns of riverbank erosion and deposition in a large, tropical, macrotidal river in Northern Australia; the Daly River. In particular, we aimed to determine if recreational boat use was impacting bank erosion in this dynamic river. Erosion pins were installed at multiple levels on both banks at 10 sites along a 34 km reach of the river. Measurements were made every four to six weeks during the low water dry season, and opportunistically during the wet season (flooding period) and seasonal transition periods. A bank geotechnical assessment, riverbed cross‐sections and site bathymetry were undertaken. Whilst the wet season was a period of substantial erosion (mean rate of 0.64 mm day^?1), the highest mean erosion rate (3.6 mm day^?1) was observed in the early dry season (April to May), a period of stabilizing water levels but greatest boat traffic. Bank erosion at this time was measured on both sides of the river and the inside of meander bends, which is atypical of normal riverine bank erosion patterns, and indicative of erosion due to boat wash. As the dry season progressed, significant spatial differences in erosion rates were evident, where erosion was observed at sites upstream of a large shallow sand bar, while sites downstream from the sand bar gained material through the deposition of tidally transported sediment. This study highlights the importance of understanding the significance and interaction of various erosive factors in tropical tidal rivers and has demonstrated that boat wash may be an important contributor to dry season bank erosion in these systems. We encourage management agencies to consider the role of boats in any future river management program in these systems.     

Parallel and efficient Boolean on polygonal solids

We present a novel framework which can efficiently evaluate approximate Boolean set operations for B-rep models by highly parallel algorithms. This is achieved by taking axis-aligned surfels of Layered Depth Images (LDI) as a bridge and performing Boolean operations on the structured points. As compared with prior surfel-based approaches, this paper has much improvement. Firstly, we adopt key-data pairs to store LDI more compactly. Secondly, robust depth peeling is investigated to overcome the bottleneck of layer-complexity. Thirdly, an out-of-core tiling technique is presented to overcome the limitation of memory. Real-time feedback is provided by streaming the proposed pipeline on the many-core graphics hardware.     

Experimental validation and model development for thermal transmittances of porous window screens and horizontal louvred blind systems

Virtually every home in the US has some form of shades, blinds, drapes, or other window attachment, but few have been designed for energy savings. In order to provide a common basis of comparison for thermal performance it is important to have validated simulation tools. This paper outlines a review and validation of the ISO 15099 centre-of-glass thermal transmittance correlations for naturally ventilated cavities through measurement and detailed simulations. The focus is on the impacts of room-side ventilated cavities, such as those found with solar screens and horizontal louvred blinds. The thermal transmittance of these systems is measured experimentally, simulated using computational fluid dynamics analysis, and simulated utilizing simplified correlations from ISO 15099. Correlation coefficients are proposed for the ISO 15099 algorithm that reduces the mean error between measured and simulated heat flux for typical solar screens from 16% to 3.5% and from 13% to 1% for horizontal blinds.     

Development of carbon conductive additives for advanced lithium ion batteries

The newly developed conductive carbon blacks C-NERGY™ Super C65 and C-NERGY™ Super C45 were studied with regard to their performance as conductive additives in positive lithium ion battery electrodes and compared to other reference conductive carbon blacks. The lowest electrical volume resistivity and highest compressibility were found for C-NERGY™ Super C45 dry-mixed with LiCoO₂ powder. Mixing by high shear forces in acetone dispersion improved the electrical resistivity and compressibility of the C-NERGY™ Super C65 containing LiCoO₂ mixture to the same level obtained for the C-NERGY™ Super C45 mixture in the same process. Acetone dispersions of C-NERGY™ Super C45 and LiCoO₂ showed the lowest viscosities attributed to the carbon black's specific BET surface area of 45 m² g⁻¹ being the lowest of all carbon blacks studied. The easy dispersibility of C-NERGY™ Super C45 in LiCoO₂ could be explained by its particular surface group chemistry characterized by time-of-flight secondary ion mass spectrometry. The electrical volume resistivity of the LiCoO₂/carbon black mixtures was in line with the high current rate performance of half-cells with related LiCoO₂ electrodes. Compared to the investigated carbon blacks, the electrical volume resistivity of the graphite conductive additives C-NERGY™ KS6L and C-NERGY™ SFG6L at different concentrations in LiCoO₂ powders showed higher critical volume fractions but lower ultimate resistivity levels. Adding one of these graphites to the carbon black conductive mass improved the electrode density and, at concentrations above the critical volume fraction of the graphite component, significantly decreased the ultimate resistivity level of the LiCoO₂ electrode mass.     

Feasibility Study of Continuous Casting of Steel Billets in Twin-Belt Caster

Metallurgical and Materials Transactions B - Integrated casting and rolling in a series production line is well established for the non-ferrous metals through the use of twin-belt casting...     

Effect of Microstructural Features on Magnetic Properties of High-Carbon Steel

Metallurgical and Materials Transactions A - Industrially produced high-carbon steel has been heat treated in order to obtain various microstructures of the single phase of martensite, bainite,...     

Heartwood of Cupressus lusitanica, C. macrocarpa, Leyland and Ovens cypress and prediction of its durability using near-infrared spectroscopy

The heartwood of plantation-grown Cupressus lusitanica, C. macrocarpa, Leyland and Ovens cypress (×Cuprocyparis leylandii and ×C. ovensii) from trials in New Zealand, was evaluated using breast height increment cores and in vitro decay tests with fungal cultures to determine the variation in the heartwood content and natural durability, and its prediction using near-infrared (NIR) spectroscopy. The increment core measurements showed the length of the cores was strongly influenced by the stocking and site, but the heartwood content and weight loss with decay testing were strongly influenced by species and genotype. The heartwood content was consistently high for C. macrocarpa, but varied widely for C. lusitanica, and the Leyland and Ovens cypress clones. The weight loss was similar for the species and cypress clones, with the heartwood classified as very durable and durable, but there were differences in the distributions of less durable heartwood. The NIR calibration models of mass loss with fungal decay testing had ratios of prediction to deviation (RPD) of 1.0–1.3, which suggests the models could be used to segregate the heartwood for high and low values of natural durability.     

Inter-Tissue Differences in Fatty Acid Incorporation as a Result of Dietary Oil Manipulation in Port Jackson Sharks (Heterodontus portusjacksoni)

Fatty acid profile analysis is a tool for dietary investigation that may complement traditional stomach contents analysis. While recent studies have shown that the liver of sharks fed different diets have differing fatty acid profiles, the degree to which diet is reflected in shark blood serum and muscle tissue is still poorly understood. An 18-week controlled feeding experiment was undertaken using captive Port Jackson sharks (Heterodontus portusjacksoni). Sharks were fed exclusive diets of artificial pellets treated with fish or poultry oil and sampled every 6 weeks. The fatty acid profiles from liver, blood serum, and muscle were affected differently, with the period from which significant differences were observed varying by tissue and diet type. The total fatty acid profiles of fish oil and poultry oil fed sharks were significantly different from week 12 onwards in the liver and blood serum, but significant differences were only observed by week 18 in the muscle tissue of sharks fed different diets. The drivers of dissimilarity which aligned with dietary input were 14:0, 18:2n-6, 20:5n-3, 18:1n-9 and 22:6n-3 in the liver and blood serum. Dietary fatty acids accumulated more consistently in the liver than in the blood plasma or muscle, likely due to its role as the central organ for fat processing and storage. Blood serum and muscle fatty acid profiles were influenced by diet, but fluctuated over-time. The low level of correlation between diet and muscle FA profiles is likely a result of low levels of fat (<1 %) in the muscle and the domination of structural, cell-membrane phospholipids in shark muscle tissues. Our findings describe inter-tissue differences in the incorporation of fatty acids from the diet to consumer, which should be taken into account when interpreting dietary patterns from fatty acid profiles.