3,702 research outputs found

    Evaluation and control of mechanical degradation of austenitic stainless 310S steel substrate during coated superconductor processing

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    The superconductor industry considers cold-rolled austenitic stainless 310S steel a less expensive substitute for Hastelloy X as a substrate for coated superconductor. However, the mechanical properties of cold-rolled 310S substrate degrade significantly in the superconductor deposition process. To overcome this, we applied hot rolling at 900 A degrees C (or 1000 A degrees C) to the 310S substrate. To check the property changes, a simulated annealing condition equivalent to that used in manufacturing was determined and applied. The effects of the hot rolling on the substrate were evaluated by analyzing its physical properties and texture.Web of Science24345444

    Balloon occlusion retrograde transvenous obliteration of gastric varices in two non-cirrhotic patients with portal vein thrombosis

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    This report describes two non-cirrhotic patients with portal vein thrombosis who underwent successful balloon occlusion retrograde transvenous obliteration (BRTO) of gastric varices with a satisfactory response and no complications. One patient was a 35-year-old female with a history of Crohn's disease, status post-total abdominal colectomy, and portal vein and mesenteric vein thrombosis. The other patient was a 51-year-old female with necrotizing pancreatitis, portal vein thrombosis, and gastric varices. The BRTO procedure was a useful treatment for gastric varices in non-cirrhotic patients with portal vein thrombosis in the presence of a gastrorenal shunt

    Effective indenter radius and frame compliance in instrumented indentation testing using a spherical indenter

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    We introduce a novel method to correct for imperfect indenter geometry and frame compliance in instrumented indentation testing with a spherical indenter. Effective radii were measured directly from residual indentation marks at various contact depths (ratio of contact depth to indenter radius between 0.1 and 0.9) and were determined as a function of contact depth. Frame compliance was found to depend on contact depth especially at small indentation depths, which is successfully explained using the concept of an extended frame boundary. Improved representative stress-strain values as well as hardness and elastic modulus were obtained over the entire contact depth

    Comparison of transjugular intrahepatic portosystemic shunt with covered stent and balloon-occluded retrograde transvenous obliteration in managing isolated gastric varices

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    OBJECTIVE: Although a transjugular intrahepatic portosystemic shunt (TIPS) is commonly placed to manage isolated gastric varices, balloon-occluded retrograde transvenous obliteration (BRTO) has also been used. We compare the long-term outcomes from these procedures based on our institutional experience. MATERIALS AND METHODS: We conducted a retrospective review of patients with isolated gastric varices who underwent either TIPS with a covered stent or BRTO between January 2000 and July 2013. We identified 52 consecutive patients, 27 who had received TIPS with a covered stent and 25 who had received BRTO. We compared procedural complications, re-bleeding rates, and clinical outcomes between the two groups. RESULTS: There were no significant differences in procedural complications between patients who underwent TIPS (7%) and those who underwent BRTO (12%) (p = 0.57). There were also no statistically significant differences in re-bleeding rates from gastric varices between the two groups (TIPS, 7% [2/27]; BRTO, 8% [2/25]; p = 0.94) or in developing new ascites following either procedure (TIPS, 4%; BRTO, 4%; p = 0.96); significantly more patients who underwent TIPS developed hepatic encephalopathy (22%) than did those who underwent BRTO (0%, p = 0.01). There was no statistically significant difference in mean survival between the two groups (TIPS, 30 months; BRTO, 24 months; p = 0.16); median survival for the patients who received TIPS was 16.6 months, and for those who underwent BRTO, it was 26.6 months. CONCLUSION: BRTO is an effective method of treating isolated gastric varices with similar outcomes and complication rates to those of TIPS with a covered stent but with a lower rate of hepatic encephalopathy

    Conventional Vickers and true instrumented indentation hardness determined by instrumented indentation tests

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    We evaluate Vickers hardness and true instrumented indentation test (IIT) hardness of 24 metals over a wide range of mechanical properties using just IIT parameters by taking into account the real contact morphology beneath the Vickers indenter. Correlating the conventional Vickers hardness, indentation contact morphology, and IIT parameters for the 24 metals reveals relationships between contact depths and apparent material properties. We report the conventional Vickers and true IIT hardnesses measured only from IIT contact depths; these agree well with directly measured hardnesses within ±6% for Vickers hardness and ±10% for true IIT hardness

    Effect of admixtures on the yield stresses of cement pastes under high hydrostatic pressures

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    When cement-based materials are transported at a construction site, they undergo high pressures during the pumping process. The rheological properties of the materials under such high pressures are unknown, and estimating the workability of the materials after pumping is a complex problem. Among various influential factors on the rheology of concrete, this study investigated the effect of mineral and chemical admixtures on the high-pressure rheology. A rheometer was fabricated that could measure the rheological properties while maintaining a high pressure to simulate the pumping process. The effects of superplasticizer, silica fume, nanoclay, fly ash, or ground granulated blast furnace slag were investigated when mixed with two control cement pastes. The water-to-cement ratios were 0.35 and 0.50.ope

    Mitochondria-mediated defense mechanisms against pathogens in Caenorhabditis elegans

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    Mitochondria are crucial organelles that generate cellular energy and metabolites. Recent studies indicate that mitochondria also regulate immunity. In this review, we discuss key roles of mitochondria in immunity against pathogen infection and underlying mechanisms, focusing on discoveries using Caenorhabditis elegans. Various mitochondrial processes, including mitochondrial surveillance mechanisms, mitochondrial unfolded protein response (UPRmt), mitophagy, and reactive oxygen species (ROS) production, contribute to immune responses and resistance of C. elegans against pathogens. Biological processes of C. elegans are usually conserved across phyla. Thus, understanding the mechanisms of mitochondria-mediated defense responses in C. elegans may provide insights into similar mechanisms in complex organisms, including mammals.110Ysciescopuskc

    Structural Optimization of a Knuckle with Consideration of Stiffness and Durability Requirements

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    The automobile’s knuckle is connected to the parts of the steering system and the suspension system and it is used for adjusting the direction of a rotation through its attachment to the wheel. This study changes the existing material made of GCD45 to Al6082M and recommends the lightweight design of the knuckle as the optimal design technique to be installed in small cars. Six shape design variables were selected for the optimization of the knuckle and the criteria relevant to stiffness and durability were considered as the design requirements during the optimization process. The metamodel-based optimization method that uses the kriging interpolation method as the optimization technique was applied. The result shows that all constraints for stiffness and durability are satisfied using A16082M, while reducing the weight of the knuckle by 60% compared to that of the existing GCD450
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