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In comparison to carbon nanostructures, hexagonal boron nitride (hBN) nanostructures show better biocompatibility and lower cytotoxicity. However, research studies on hBN nanostructures for biomedical applications are still in an early stage, which limits the current knowledge about this group of materials, particularly their functionalization. Herein, we report a simple and scalable two-step method for the simultaneous synthesis and functionalization of hBN nanosheets (NSHs) and nanoscrolls (NSCs). The first step is conventional chemical exfoliation under alkaline conditions to weaken the interlayer interactions. The second step is exposure to low-frequency ultrasonic irradiation to obtain partially oxidized NSHs and NSCs. The successful formation of both NSHs and NSCs is confirmed using electron microscopy. The effective incorporation of O atoms into hBN nanostructures was confirmed through (i) the changes in the optical bandgaps deduced from UV–vis absorption, and (ii) the decrease in B atoms bonded to three N atoms and the increase in the BNxOy component observed using high-resolution XPS. Raman spectroscopy was used to analyze the evolution of the active phonon modes upon further exposure to irradiation, and showed a phase transition from sp2 to a mixture of sp2–sp3 bondings at the occurrence of the shape transformation from NSHs to NSCs., R. Miranti thanks to Research Council of Norway for the financial support under FRINATEK Project Nr. 275139. M.S. Qayyum thanks NTNU NanoLab support through the Norwegian Micro- and Nano-Fabrication Facility, NorFab, (Grant No. 245963/F50).

Motorbike shock absorbers of gravity die cast aluminum A356.0 alloy were being imported in the as-cast condition and later on machined at local foundries and workshops by sub-vendors to achieve the required dimensions and on many occasions a nearly complete solid block was cast and machined to achieve the desired shape but this process not only lowered the metallic yield but also the high machining costs and time required made it very uneconomical. Motorbike shock absorbers are critical vehicle components which are always under load and must never fail suddenly without warning therefore they need to be free of defects like shrinkage and micro-porosity. The thin wall thickness of 6mm and troublesome nature of cores required makes this component quite difficult for the conventional metal caster. The current research paper deals with the methoding, die designing, modeling and simulation, optimization and finally casting of these components following the data produced by the former. Initially a single piece per mold was suggested but later on considering the economics of the project two pieces i.e. left and right were recommended to be cast from a single sprue in each die with a vertically parted permanent die mold. For the methoding calculations the Thermal modulus has been used instead of the conventional casting modulus and for gating the naturally pressurized system is incorporated. Throughout the simulation process a significant number of iterations were made to achieve the final design which ensured a laminar flow of liquid aluminum below the critical velocity limit; the actual die casting results yielded good comparison with the simulation studies showing shrinkage cavity away from the risers and micro-porosity only in ingates.

Boron nitride nanoscrolls (BNSs) are open-ended, one-dimensional nanostructures made by the process of rolling boron nitride nanosheets into a scroll-like morphology. BNSs offer a high surface area to volume ratio and possess many unique properties (similar to carbon nanotubes, carbon nanoscrolls, and boron nitride nanotubes) such as high resistance to oxidation, chemical stability, increased lubrication, high-temperature resistance, electrical insulation, the ability to cap molecules inside and at the ends, and a wide bandgap regardless of chirality. Despite these attractive features and properties well suited for applications in biotechnology, energy storage, and electronics, the true potential of boron nitride and BNS as the next “miracle material” is yet to be fully explored. In this critical review, we assess, for the first time, various studies published on the formation and structural and dynamic characteristics of BNS; potential routes for BNS synthesis; and the toxicology of BNS. Finally, the future perspectives of BNS are discussed in view of its unique and exceptional candidacy for many (real-world) applications.