439 research outputs found
Distribution of Si, Fe, and Ni in the Intracluster Medium of the Coma Cluster
We studied the distributions of Si, Fe, and Ni in the intracluster medium
(ICM) of the Coma cluster, one of the largest clusters in the nearby universe,
using XMM-Newton data up to 0.5 r180 and Suzaku data of the central region up
to 0.16 r180. Using the flux ratios of Ly alpha of H-like Si and 7.8 keV blend
to K alpha of He-like Fe, the abundance ratios of Si to Fe and Ni to Fe of the
ICM were derived using APEC model v2.0.1. The Si/Fe ratio in the ICM of the
Coma cluster shows no radial gradient. The emission weighted averages of the
Si/Fe ratio in the ICM within 0.0--0.2 r180, 0.2--0.5 r180, and 0.0--0.5 r180
are 0.97 +- 0.11, 1.05 +- 0.36 and 0.99 +- 0.13, respectively, in solar units
using the solar abundance of Lodders (2003). These values are close to those of
smaller clusters and groups of galaxies. Using the Suzaku data of the central
region, the derived Ni/Fe ratio of the ICM is 0.6--1.5 in solar units,
according to the same solar abundance table. The systematic difference in the
derived abundance ratios by different plasma codes are about 10%. Therefore,
for the ICM in the Coma cluster, the abundance pattern of Si, Fe, and Ni is
consistent with the same mixture of the yields of SN II and SN Ia in our
Galaxy. Within 0.5 r180}, the cumulative iron-mass-to-light ratio increases
with radius, and its radial profile is similar to those of relaxed smaller
clusters with cD galaxies at their center. Considering the observed Si/Fe
ratio, the cumulative metal-mass-to-light ratios at 0.5 r180 are compared with
theoretical expectations.Comment: 10 pages, 7 figures, accepted for publication in PAS
Iron Oxide-Based Catalyst for Catalytic Cracking of Heavy Oil
This chapter describes an iron oxide catalyst containing Zr and Al for production of light hydrocarbons by catalytic cracking of petroleum residual oil in a steam atmosphere. The catalyst was hematite structure and useful for decomposition and desulfurization of residual oil. After lattice oxygen of iron oxide reacted with heavy oil fraction of residual oil, oxygen species generated from steam were supplied to iron oxide lattice and reacts with heavy oil fraction, producing light hydrocarbons and carbon dioxide. When the oxygen species were generated from steam, hydrogen species were simultaneously generated from steam. The hydrogen species were transferred to light hydrocarbons, hydrogen sulfide, and residue deposited on the catalyst. Supplies of the hydrogen species to light hydrocarbons suppressed alkene generation. Generation of hydrogen sulfide indicated decomposition of sulfur compounds of residual oil. The sulfur concentration of product oil decreased compared to the concentration of residual oil. Some oxygen species could be transferred to sulfur dioxide. Accordingly, hydrogenation and oxidation by the hydrogen and oxygen species derived from steam provided the decomposition and desulfurization of residual oil with the iron oxide-based catalyst in a steam atmosphere
Intelligent Prediction and Detection of Diabetes Mellitus Using Machine Learning
One of the diseases with a fairly high number of sufferers today is Diabetes Mellitus. The increase in the number of people with diabetes is caused by delays in diagnosis and also difficulties in monitoring the blood sugar level. Therefore, a solution is needed to overcome this problem, namely a blood sugar level monitoring system to predict and detect. The blood sugar level monitoring system is an intelligent system that can monitor blood sugar levels in Diabetes Mellitus patients. This system aims to make it easier for patients to check blood sugar levels regularly, to minimize the occurrence of increased blood sugar levels that aggravate the disease. Moreover, machine learning algorithms are a viable method used in recent studies for analyzing, predicting, and classifying health data while improving the health conditions of telemonitoring and telediagnosis. The main purpose of this article is to employ machine learning algorithms for blood sugar level classification in real time. The results of this study indicate that the system can be used to monitor blood sugar levels. The results of the implementation of the system that can be used by users include monitoring the results of measuring blood sugar levels.
Keywords: Monitoring Machine Learning, Prediction, Diabetes Mellitus, Data Minin
Finite element analysis of severe plastic deformation of difficult-to-work material by equal-channel angular pressing at ambient temperature
An alternative technique of the equal-channel angular pressing (ECAP) process for difficult-to-work materials at ambient temperature is proposed by embedding a difficult-to-work material into an easy-to-work material. The easy-to-work material as a host material assists the deformation of the difficult-to-work material. The ECAP process is simulated by the finite element method (FEM). For this study, Ti as the difficult-to-work material is embedded into an Al-based functionally graded material (FGM) matrix. FEM is conducted with Ti embedded into a different host material type as well as a different die channel geometry. The strain distribution of the specimen after a single ECAP pass is analyzed. From the obtained results, it is found that the strain distribution in Ti is strongly influenced by the host material and the shape of the die channe
New Processing Routes for Functionally Graded Materials and Structures through Combinations of Powder Metallurgy and Casting
New processing routes for metal-matrix functionally graded materials (FGMs) and structures through combinations of powder metallurgy and casting are described in this chapter. Centrifugal mixed-powder method is introduced as a processing method for metal-matrix FGMs at first. The centrifugal mixed-powder method is a developed technique of centrifugal casting by setting predesigned mixed powder in a spinning mold in advance. As an example of processed FGMs by this method in our previous studies, Cu-based FGMs with dispersed diamond particles are shown. Graded structures in the Cu-based FGMs are investigated through scanning electron microscope (SEM) observations of microstructures. As the latest processing method for metal-matrix FGMs developed by our research group, centrifugal sintered-casting method is shown. The centrifugal sintered-casting method is a modified processing technique of the centrifugal mixed-powder method. In the centrifugal sintered-casting method, FGMs are processed by the combination of centrifugal sintering and centrifugal casting. Al–Si alloy and Cu-based FGMs with dispersed diamond particles are introduced as examples. Applications of metal-matrix FGMs processed by the centrifugal sintered-casting method are also described. Fabricated metal-matrix FGMs can be used as grinding wheel and applied to carbon fiber-reinforced plastic (CFRP) machining
Detection of a low-eccentricity and super-massive planet to the subgiant HD 38801
We report the detection of a large mass planet orbiting around the K0
metal-rich subgiant HD38801 () by precise radial velocity (RV)
measurements from the Subaru Telescope and the Keck Telescope. The star has a
mass of and metallicity of [Fe/H]= +0.26. The RV variations are
consistent with a circular orbit with a period of 696.0 days and a velocity
semiamplitude of 200.0\mps, which yield a minimum-mass for the companion of
10.7\mjup and semimajor axis of 1.71 AU. Such super-massive objects with very
low-eccentricities and hundreds of days period are uncommon among the ensemble
of known exoplanets
Palmitate induces reactive oxygen species production and β-cell dysfunction by activating nicotinamide adenine dinucleotide phosphate oxidase through Src signaling.
[Aims/Introduction]Chronic hyperlipidemia impairs pancreatic β-cell function, referred to as lipotoxicity. We have reported an important role of endogenous reactive oxygen species (ROS) overproduction by activation of Src, a non-receptor tyrosine kinase, in impaired glucose-induced insulin secretion (GIIS) from diabetic rat islets. In the present study, we investigated the role of ROS production by Src signaling in palmitate-induced dysfunction of β-cells. [Materials and Methods]After rat insulinoma INS-1D cells were exposed to 0.6 mmol/L palmitate for 24 h (palmitate exposure); GIIS, ROS production and nicotinamide adenine dinucleotide phosphate oxidase (NOX) activity were examined with or without exposure to10 μmol/L 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), a Src inhibitior, for 30 or 60 min. [Results]Exposure to PP2 recovered impaired GIIS and decreased ROS overproduction as a result of palmitate exposure. Palmitate exposure increased activity of NOX and protein levels of NOX2, a pathological ROS source in β-cells. Palmitate exposure increased the protein level of p47phox, a regulatory protein of NOX2, in membrane fraction compared with control, which was reduced by PP2. Transfection of small interfering ribonucleic acid of p47phox suppressed the augmented p47phox protein level in membrane fraction, decreased augmented ROS production and increased impaired GΙIS by palmitate exposure. In addition, exposure to PP2 ameliorated impaired GIIS and decreased ROS production in isolated islets of KK-Ay mice, an obese diabetic model with hyperlipidemia. [Conclusions]Activation of NOX through Src signaling plays an important role in ROS overproduction and impaired GΙIS caused by chronic exposure to palmitate, suggesting a lipotoxic mechanism of β-cell dysfunction of obese mice
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