170 research outputs found

    Microstructural Characteristics and Mechanical Behaviors of New Type SIMA Processed Aluminum Alloy

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    In this chapter, a new type strain-induced melt activation (SIMA) process for Al-Mg-Si alloys was used. The microstructural characteristics, formability at elevated temperature and mechanical properties were estimated. The high-hardness globular grain boundaries are formed by eutectic phases. This new type SIMA process has proved that it can decrease high temperature compression resistance and improve ability of metal flowing at high temperature. After SIMA forming process, the mechanical properties of materials can be improved via artificial aging and can be competed with general artificial aged materials. All results show that this SIMA process is a potential process

    Improvement of Charge-Discharge Characteristics of the Mg-Ni Powder Electrodes at 55°C

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    Magnesium-nickel (Mg-Ni) powders are used as the anode materials for secondary lithium (Li) ion batteries. Mg-Ni powders with ratios of 1 : 1 (Mg : Ni) are prepared and their structure and electrochemical behavior at room temperature and 55°C are investigated. The results show that adding Ni powders to Mg powders can reduce the charge-discharge capacities and improve cycling life. In charge-discharge cycle testing at 55°C, the Li ion concentration gradually increased with increasing the duration of electrochemical reactions, indicating that the charge-discharge capacities increase with increment of cycling number. The formation of a solid electrolyte interface (SEI) layer restrains Mg ions from dissolving into the electrolyte and thus improves the charge-discharge capacities at high temperature

    Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

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    Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

    MICROSTRUCTURAL HEALING WITH INTERFACIAL REACTION LAYERS ON THE ADHESIVE STRENGTH ENHANCEMENT OF PLASMA-SPRAYED HYDROXYAPATITE COATINGS

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    The effect of hydrothermal crystallization and adding reinforced intermediate layers on improving the tensile adhesion of plasma-sprayed HA coatings (HAC) was investigated. The experimental results show that the index of crystallinity (IOC) and phase purity of hydrothermally-treated HAC (HT-HAC) are increased by the low-temperature hydrothermal treatment. The microstructural healing effect with nano-size HA crystallites is significant to diminish the defects and prevent mechanical strength degradation for the HT-HAC. XPS analysis demonstrates that hydrothermal crystallization helps to promote the interfacial Ti – OH chemical reaction. HA composite coatings with CP - Ti and ZrO2intermediate layers provide another strengthening effect compared with the hydrothermal-heating method. The inter-diffusion of Ca results in a chemical bonding at the HA / ZrO2interface, which results in the increase of the adhesive strength of composite coatings. The fracture behavior is different between the crystallization-induced HAC and the composite coatings. The HT-HAC remains on the substrate with an evident cohesive failure. The adhesive failure occurred at HA /intermediate layers for composite coatings. Failures with less percentage area of interfacial fracture are indicative of a higher strength of a coating.</jats:p
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