19,998 research outputs found

    Microscopy of glazed layers formed during high temperature sliding wear at 750C

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    The evolution of microstructures in the glazed layer formed during high temperature sliding wear of Nimonic 80A against Stellite 6 at 750 ◦C using a speed of 0.314ms−1 under a load of 7N has been investigated using scanning electron microscopy (SEM), energy dispersive analysis by X-ray (EDX), X-ray diffraction (XRD) analysis, scanning tunnelling microscopy (STM) and transmission electron microscopy (TEM). The results indicate the formation of a wear resistant nano-structured glazed layer. The mechanisms responsible for the formation of the nano-polycrystalline glazed layer are discussed

    A study on inclusion formation mechanism in alpha-LiIO sub 3 crystals

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    The spatial distribution of inclusions in alpha-LiIO3 crystals by means of an argon laser beam scanning technique is studied. The effects of crystal dimensions and solution fluid flow on the inclusion formation in the alpha-LiIO3 crystals were observed. It was further shown that the fluid flow plays an important role in the formation of inclusions. The results obtained were further applied and verified by growing a perfect alpha-LiIO3 single crystal. An experimental foundation for further theoretical studies on the causes of inclusions may be provided

    A New Current Mode SIMO-Type Universal Biquad Employing Multi-Output Current Conveyors (MOCCIIs)

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    This study presents a new current-mode singleinput and multi-output (SIMO) type universal biquad circuit using second generation multi-output current conveyors (MOCCII) as the active components. The proposed circuit employs three MOCCIIs, two grounded capacitors and four grounded resistors, therefore offers electroning tuning possibilities. It can simultaneously realize second order low-pass, band-pass, high-pass, notch and all-pass filters. The circuit is cascadable and has low sensitivities. It provides independent control of ω0 (natural angular frequency) and Q (quality factor). The influences of MOCCII parasitic elements have been analyzed and simulated using PSPICE. Experimental results including frequency responses of low-pass, high-pass, band-pass and band-stop filters, as well as frequency responses of filters with different ω0 (keeping Q invariable) and different Q (keeping ω0 invariable) are shown to be in agreement with theory

    Sustainable leaching process of phosphates from animal bones to alleviate the world phosphate crisis

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    Lack of available phosphorus (P) minerals and their very localized regional distribution threatens world food production. Traditional farming methods that recycle various biological wastes and manure for localized fertilization of farmland are our role model, but come with risks such as hygiene, water toxification and passed-on diseases. Here, we present a bran-new hydrothermal process which turns animal bones of kitchen wastes into secondary P sources for fertilization, showing that this hydrothermal humification (HTH) process under 200 °C for 24 h completely disintegrates chemical structure of the biomass, while the simultaneously in-situ prepared artificial humic acid (A-HA) etches even macroscopic bones. Notably, A-HA can solubilize the insoluble P existing in animal bones partly as directly dissolved phosphorus (DP), accounting for 6.36 % of total phosphorus (TP) in the bone wastes. Characterization methods indicate that oxygen-containing functional groups (i.e., -COOH and phenolic-OH) of A-HA can help to corrode bones, causing Ca5(PO4)3(OH) to be decomposed into a large number of more active P minerals, furthermore, leading to high DP (96.79 mg/L) content and the formation of new P-based species. Pot planting experiments show that the resulting liquids were applied as a fertilizer and lead to a significant promotion of the growth of seedlings
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