35 research outputs found

    Influences of different degassing processes on refining effect and properties of 4004 Al alloy

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    In order to improve the plasticity of 4004 Al alloy and subsequently the productivity of 4004 Al foil, the research studied in detail the influence of the rotary impeller degassing process on the refining effect of 4004 Al alloy, in which the impacts of four major parameters: gas flow, rotational speed, refining time, and stewing time, on degassing rate of 4004 Al alloy was systematically studied by using an orthogonal experiment methodology. Results show that the rotational speed has the greatest impact on the degassing of 4004 Al alloy, followed by gas flow and refining time; stewing time has the least impact. The optimum purification parameters obtained by current orthogonal analysis were: rotor speed of 500 rĀ·min-1, inert gas flow of 0.4 mLĀ·h-1, refining time of 15 min, and stewing time of 6 min. Degassing rate using the optimum parameters reaches 68%. In addition, the comparison experiments among C2Cl6 refining, rotary impeller degassing, and combined treatment of C2Cl6 refining and rotary impeller degassing for 4004 Al alloy were performed. The experimental data indicated that the combined treatment of C2Cl6 refining and rotary impeller degassing has the best degassing effect. Degassing rate of C2Cl6 refining, rotary impeller degassing and combined refining treatment is 39%, 69.1% and 76.9%, respectively. The mechanical properties of the specimen refined by rotary impeller degassing were higher than those by C2Cl6 refining, but lower than those by combined refining treatment

    Candida haemulonii Species Complex: Emerging Fungal Pathogens of the Metschnikowiaceae Clade

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    Candida species, the most common fungal pathogens affecting humans, cause not only superficial infections but also life-threatening invasive infections, particularly in immunocompromised individuals. Although Candida albicans remains the most frequent cause of candidiasis, infections caused by non- albicans Candida species have been increasingly reported in clinical settings over the past two decades. Recently, species of the Metschnikowiaceae clade including the ā€œsuperbugā€ Candida auris and other members of the Candida haemulonii species complex have attracted substantial attention for their multidrug resistance and high rates of transmission in clinical settings. In this review, we summarize the epidemiology, biology, virulence, and drug resistance of the C. haemulonii species complex and discuss potential reasons for the recent increase in the prevalence of infections caused by non- albicans species in clinical settings

    US Cosmic Visions: New Ideas in Dark Matter 2017: Community Report

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    This white paper summarizes the workshop "U.S. Cosmic Visions: New Ideas in Dark Matter" held at University of Maryland on March 23-25, 2017.Comment: 102 pages + reference

    Effect of residual Al content on microstructure and mechanical properties of Grade B+Steel for castings for locomotives

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    The bogie made of Grade B+ steel is one of the most important parts of heavy haul trains. Some accidents were found to be the result of fracture failure of the bogies. It is very important to find the reason why the fracture failure occurred. Because Al was added for the final deoxidation during the smelting process of the Grade B+Steel, residual Al existed to some extent in the castings. High residual Al content in the bogie casting was presumed to be the reason for the fracture. In this work, the influence of residual Al content in the range of 0.015wt.% to 0.3wt.% on the microstructure and mechanical properties of the Grade B+ Steel was studied. The experimental results showed that when the residual Al content is between 0.02wt.% and 0.20wt.%, the mechanical properties of the steel meet the requirements of technical specification for heavy haul train parts, and the fracture is typical plastic fractures. If the residual Al content is less than 0.02wt.%, the microstructures are coarse, and the mechanical properties can not meet the demand of bogie steel castings. When the residual Al content is more than 0.2wt.%, the elongation, reduction of area, and low-temperature impact energy markedly deteriorate. The fracture mode then changes from plastic fracture to cleavage brittle fracture. Therefore, the amount of Al addition for the final deoxidation during the smelting process must be strictly controlled. The optimum addition amount needs to be controlled within the range of 0.02wt.% to 0.20wt.% for the Grade B+Steel

    Preparation and Thermal Shock Performance of ZrO<sub>2</sub>/NiCrAlY Thermal Barrier Coating

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    Electric spark deposition (ESD) combining with micro-arc oxidation (MAO) were employed to fabricate ZrO2/NiCrAlY thermal barrier coating (TBC) on GH4169 substrate. Firstly, a NiCrAlY coating with thickness of 250 Ī¼m was deposited on GH4169 substrate by ESD. Secondly, a Zr coating with thickness of 150 Ī¼m was deposited on NiCrAlY coating followed by MAO of the Zr coating. The thermal shock performances of the coatings under different temperatures were investigated. The results indicate that the thermal cycle numbers of the coatings at 750ā„ƒ, 850 ā„ƒ and 950ā„ƒ are 51, 32, and 19 respectively

    Internal hernia through hepatic falciform ligament iatrogenic defect in a neonate: A case report and review of the literature

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    Internal hernia through an iatrogenic defect in the hepatic falciform ligament and acquired jejunal atresia in a 8-day-old neonate was reported. The PubMed, MEDLINE, CNKI, Wanfang and Weipu databases were searched The literature about the hepatic falciform ligament iatrogenic defect causing internal hernia was analysed. Ten other cases were collected from the world literature. Herniated intestinal necrosis was found in four cases. All cases were recovered uneventfully after operation. Internal herniation through an iatrogenic defect in the hepatic falciform ligament is extremely rare. However, the case reports are increasing, especially in the era of laparoscopic surgery. Adequate closure or open the defect is essential to prevent internal hernia occurrence

    A Broad-Spectrum, Catalytic Amidation of Sulfonyl Fluorides and Fluorosulfates

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    A broad-spectrum, catalytic amidation has been developed to prepare various sulfonamides and sulfamates including sterically hindered ones. In addition, the potentials of this methodology in medicinal and process chemistry have been demonstrated by the multidecagram-scale synthesis of an amantadine derivative and the synthesis of the marketed drug Fedratinib for myelofibrosis

    Achieving strength-ductility synergy in semi-solid squeeze cast 6TiB2/Alā€“17Siā€“4Cu composites by heat treatment

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    This study aims to achieve synergistic strength-ductility enhancement of semi-solid squeeze cast 6TiB2/Alā€“17Siā€“4Cu composites through in-situ particle strengthening and T6 heat treatment. The microstructure and mechanical properties of 6TiB2/Alā€“17Siā€“4Cu composites with different heat treatments were investigated. TiB2 particles are semi-coherent with Ī±-Al and primary Si, respectively. The nanoscale precipitate phases were determined by their crystal orientation relationships. The results showed that they are Īø and ĪøŹ¹ phases. Meanwhile, the research results pertaining to the mechanical properties imply that the strength and ductility are enhanced by the TiB2 particles and Al2Cu precipitates. The optimum heat treatment process (solution treatment for 9Ā h at 520Ā Ā°C and aging for 8Ā h at 170Ā Ā°C) of strengthened 6TiB2/Alā€“17Siā€“4Cu composites is revealed in this study, when the ultimate tensile strength and elongation of the composites are 263.3Ā MPa and 0.51%, respectively. The mechanisms governing the enhanced strength and ductility of 6TiB2/Alā€“17Siā€“4Cu composites were discussed

    Cadherin-11-Interleukin-6 Signaling between Cardiac Fibroblast and Cardiomyocyte Promotes Ventricular Remodeling in a Mouse Pressure Overload-Induced Heart Failure Model

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    Heart failure is a serious and life-threatening disease worldwide. Cadherin-11 (Cad-11) is highly expressed in the heart and closely associated with inflammation. There is currently limited understanding on how Cad-11 contributes to cardiac remodeling and its underline molecular mechanism. We found an increased expression of Cad-11 in biopsy heart samples from heart failure patients, suggesting a link between Cad-11 and heart failure. To determine the role of Cad-11 in cardiac remodeling, Cad-11-deficient mice were used in a well-established mouse transverse aortic constriction (TAC) model. Loss of Cad11 greatly improved pressure overload-induced LV structural and electrical remodeling. IL (interleukin)-6 production was increased following TAC in WT mice and this increase was inhibited in cadherin-11āˆ’/āˆ’ mice. We further tested the effect of IL-6 on myocyte hypertrophy and fibrosis in a primary culture system. The addition of hCad-11-Fc to cultured cardiac fibroblasts increased IL-6 production and fibroblast cell activation, whereas neutralizing IL-6 with an IL-6 antibody resulted in alleviating the fibroblast activation induced by hCad-11-Fc. On the other hand, cardiomyocytes were promoted to cardiomyocyte hypertrophy when cultured in condition media collected from cardiac fibroblasts stimulated by hCad-11-Fc.Similarly, neutralizing IL-6 prevented cardiomyocyte hypertrophy. Finally, we found that MAPKs and CaMKIIā€“STAT3 pathways were activated in both hCad-11-Fc stimulated fibroblasts and cardiomyocytes treated with hCad-11-Fc stimulated fibroblast condition medium. IL-6 neutralization inhibited such MAPK and CaMKII-STAT3 signaling activation. These data demonstrate that Cad-11 functions in pressure overload-induced ventricular remodeling through inducing IL-6 secretion from cardiac fibroblasts to modulate the pathophysiology of neighboring cardiomyocytes
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