410 research outputs found

    Analysis of structure-phase states in-a-bulk hardened and a head-hardened rails

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    A layer-by-layer analysis along the central axis and over the fillet of rails for low-temperature service, rails with enhanced wear resistance and contact fatigue resistance, and for senior-grade rails, bulk oil hardened and DT 350 rails head-hardened under different conditions has been carried out by modern material science methods. Quantitative variables have been established and a comparison of structure-phase states, defective substructure and internal stress fields has been made

    Microstructure and crystallographic texture of silicon iron modified by torsion under quasihydrostatic pressure

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    The electron backscatter diffraction, X-ray diffraction analysis, electromotive force instantaneous measurement, microhardness and coercive force measurement techniques are used to explore the development of the microstructure, crystallographic texture and physico-mechanical properties of silicon iron (Fe-3% Si) alloy under quasi-hydrostatic pressure in a Bridgman anvil. It is found that the alloy deformation is accompanied by its significant hardenin

    Deformation behavior of high-mn TWIP steels processed by warm-to-hot working

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    The deformation behavior of 18%Mn TWIP steels (upon tensile tests) subjected to warm-to-hot rolling was analyzed in terms of Ludwigson-type relationship, i.e., a = K\ e”1 + exp(K - ”2 e). Parameters of Ki and ” depend on material and processing conditions and can be expressed by unique functions of inverse temperatur

    Computational Investigation of Novel Tip Leakage Mitigation Methods for High Pressure Turbine Blades

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    This paper presents preliminary findings on a possible approach to reducing tip leakage losses. In this paper a computational study was conducted on the EEE (Energy Efficient Engine) HPT (High Pressure Turbine) rotor tip geometry using the commercial numerical solver ANSYS FLUENT. The flow solver was validated against aerodynamic data acquired in the NASA Transonic Turbine Blade Cascade facility. The scope of the ongoing study is to computationally investigate how the tip leakage and overall blade losses are affected by 1. injection from the tip near the pressure side, 2. injection from the tip surface at the camber line, and 3. injection from the tip surface into the tip separation bubble. The objective is to identify the locations on the tip surface at which to place appropriately configured blowing keeping in mind the film cooling application of tip blowing holes. The validation was conducted at Reynolds numbers of 85,000, 343,000 and 685,000 and at engine realistic flow conditions. The coolant injection simulations were conducted at a Reynolds number of 343,000 based on blade chord and inlet velocity and utilized the SST turbulence model in FLUENT. The key parameters examined are the number of jets, jet angle and jet location. A coolant to inlet pressure ratio of 1.0 was studied for angles of +30 deg., -30 deg. and 90 deg. to the local free stream on the tip. For the 3 hole configuration, 3 holes spaced 3 hole diameters apart with length to diameter ratio of 1.5 were used. A simulation including 11 holes along the entire mean camber line is also presented (30 degrees toward suction side). In addition, the effect of a single hole is also compared to a flat tip with no injection. The results provide insight into tip flow control methods and can be used to guide further investigation into tip flow control. As noted in past research it is concluded that reducing leakage flow is not necessarily synonymous with reducing losses due to leakage

    The Sunyaev-Zel'dovich Infrared Experiment: A Millimeter-wave Receiver for Cluster Cosmology

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    Measurements of the Sunyaev-Zel'dovich (S-Z) effect towards distant clusters of galaxies can be used to determine the Hubble constant and the radial component of cluster peculiar velocities. Determination of the cluster peculiar velocity requires the separation of the two components of the S-Z effect, which are due to the thermal and bulk velocities of the intracluster plasma. The two components can be separated practically only at millimeter (mm) wavelengths. Measurements of the S-Z effect at mm wavelengths are subject to minimal astrophysical confusion and, therefore, provide an important test of results obtained at longer wavelengths. We describe the instrument used to make the first significant detections of the S-Z effect at millimeter wavelengths. This instrument employs new filter, detector, and readout technologies to produce sensitive measurements of differential sky brightness stable on long time scales. These advances allow drift scan observations which achieve high sensitivity while minimizing common sources of systematic error.Comment: 19 pages, 15 postscript figures, LaTeX(aaspptwo.sty), ApJ(in press

    Genes Involved in the Balance between Neuronal Survival and Death during Inflammation

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    Glucocorticoids are potent regulators of the innate immune response, and alteration in this inhibitory feedback has detrimental consequences for the neural tissue. This study profiled and investigated functionally candidate genes mediating this switch between cell survival and death during an acute inflammatory reaction subsequent to the absence of glucocorticoid signaling. Oligonucleotide microarray analysis revealed that following lipopolysaccharide (LPS) intracerebral administration at striatum level, more modulated genes presented transcription impairment than exacerbation upon glucocorticoid receptor blockage. Among impaired genes we identified ceruloplasmin (Cp), which plays a key role in iron metabolism and is implicated in a neurodegenative disease. Microglial and endothelial induction of Cp is a natural neuroprotective mechanism during inflammation, because Cp-deficient mice exhibited increased iron accumulation and demyelination when exposed to LPS and neurovascular reactivity to pneumococcal meningitis. This study has identified genes that can play a critical role in programming the innate immune response, helping to clarify the mechanisms leading to protection or damage during inflammatory conditions in the CNS

    Connectivity precedes function in the development of the visual word form area

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    What determines the cortical location at which a given functionally specific region will arise in development? We tested the hypothesis that functionally specific regions develop in their characteristic locations because of pre-existing differences in the extrinsic connectivity of that region to the rest of the brain. We exploited the visual word form area (VWFA) as a test case, scanning children with diffusion and functional imaging at age 5, before they learned to read, and at age 8, after they learned to read. We found the VWFA developed functionally in this interval and that its location in a particular child at age 8 could be predicted from that child's connectivity fingerprints (but not functional responses) at age 5. These results suggest that early connectivity instructs the functional development of the VWFA, possibly reflecting a general mechanism of cortical development.National Institutes of Health (U.S.) (Grant F32HD079169)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (Grant F32HD079169)National Institutes of Health (U.S.) (Grant R01HD067312)Eunice Kennedy Shriver National Institute of Child Health and Human Development (U.S.) (Grant R01HD067312

    Empagliflozin in patients hospitalized for acute decompensated heart failure: an expert resolution on the discussion of the EMPULSE trial

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    An online expert meeting held on November 17, 2021 reviewed the results of the randomized, double-blind, multinational, parallel-group EMPULSE trial, evaluating the clinical benefit and safety of the sodium-glucose co-transporter-2 inhibitor (SGLT2i) empagliflozin compared with placebo in patients hospitalized with acute decompensated heart failure (ADHF). Patients were included in the study regardless of ejection fraction (EF) and the presence of diabetes and randomized during hospitalization after stabilization. In addition, the EMPULSE trial used a composite result analyzed using a stratified benefit ratio — Win Ratio analysis. There is evidence of clinical benefit of empagliflozin in hospitalized patients with preserved and reduced LVEF, as well as in patients with newly diagnosed ADHF or with acute decompensation of chronic heart failure (CHF) compared with placebo, regardless of type 2 diabetes presence. The importance of the favorable results of the EMPULSE trial and its significance for clinical practice, which implies the early administration of empagliflozin for inpatients, is noted. A number of proposals have been adopted to accelerate the introduction of empagliflozin into clinical practice for patients with ADHF
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