High-temperature strength and thermal stability of a unidirectionally solidified Al2O3/YAG eutectic composite

A unidirectional solidification method was investigated to manufacture Al2O3/YAG eutectic composites with high-temperature resistance that would make them usable at very high temperatures. We were successful in manufacturing a single-crystal Al2O3/single-crystal YAG eutectic composite with a dimension of 40 mm in diameter and 70 mm in length containing no colonies or pores. This composite also displayed excellent high-temperature strength characteristics. The flexural strength was in the range 350400 MPa from room temperature up to 2073 K (just below its melting point of about 2100 K) with no apparent temperature dependence. During tensile tests above 1923 K, the eutectic composite showed evidence of plastic deformation occurring by dislocation motion, and a yield phenomenon similar to many metals was observed. In addition, the microstructure of the composite was extremely stable: after 1000 h of heat treatment at 1973 K in an air atmosphere there was no growth. The above superior high-temperature characteristics are caused by such factors as the eutectic composite having a single-crystal Al2O3/single-crystal YAG structure, the formation of a compatible interface with no amorphous phase and thermal stability, and the combined effect of a YAG phase with superior high-temperature characteristics. © 1998 Chapman & Hall     

Speech recognition using pulse-coupled neural networks with a radial basis function

We have developed a novel pulse-coupled neural network (PCNN) for speech recognition. One of the advantages of the PCNN is in its biologically based neural dynamic structure using feedback connections. To recall the memorized pattern, a radial basis function (RBF) is incorporated into the proposed PCNN. Simulation results show that the PCNN with a RBF can be useful for phoneme recognition. This work was presented in part at the 7th International Symposium on Artificial Life and Robotics, Oita, Japan, January 16–18, 2002     

Lightning occurrence data observed with lightning location systems of electric power companies in Japan: 2009–2013

Nine electric power companies in Japan have been collecting lightning data with lightning location systems. Five years of the lightning data (2009–2013) are summarized and analyzed in this paper. The recent annual number of lightning flashes of which the current is more than 10 kA in Japan is around 1 million. The variations of lightning occurrence characteristics by areas, seasons, and so on, are clarified. Meteorological conditions that may affect lightning occurrence are also discussed. Furthermore, we show that there is a clear correlation between the number of lightning strikes and the outage rate of transmission lines. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Determination of the amounts of free arachidonic acid in resident and activated rabbit alveolar macrophages by fluorometric high performance liquid chromatography

An improved method of high performance liquid chromatography (HPLC) has been developed for the separation and quantitation of low levels of free fatty acids as they occur in mammalian tissues. The fatty acid analysis is based on the esterification of the carboxylic group with 9-anthryldiazomethane (ADAM). HPLC separation and fluorescence measurement of fatty acid ADAM esters allow the determination of pmole amounts of fatty acids. The amounts of free fatty acids of resident and activated alveolar macrophages were determined by the fluorometric HPLC method. There were approximately 2 μg/10⁶ cells of free fatty acids. In resident macrophages, free 20∶4 was a minor component (0.8% of total free fatty acids), while significant amounts of 20∶4 were found in the total glycerophospholipids, representing 16.6% of the total fatty acids. A marked increase in amounts of 20∶4 (8 times) occurred in activated macrophages stimulated for 1 hr with opsonized zymosan. Small but significant increases (1.5 times) also occurred in other fatty acids. These results show that the release reaction of fatty acids was not selective for 20∶4 in alveolar macrophages after the challenge with opsonized zymosan.     

The Creep and Thermal Stability Characteristics of a Unidirectionally Solidified Al2O3/YAG Eutectic Composite

Compressive creep characteristics at 1773, 1873, and 1973 K, oxidation resistance over 1000 h at a temperature of 1973 K in ambient air, and the thermal stability characteristics at 1973 K in ambient air of a unidirectionally solidified Al2O3/YAG eutectic composite were evaluated. At a test temperature of 1873 K and a strain rate of 10–4/s, the compressive creep strength of a eutectic composite manufactured by the unidirectional solidification method is approximately 13 times higher than that of a sintered composite with the same chemical composition. The insite eutectic composite also showed greater thermal stability, with no change in mass after an exposure of 1000 hours at 1973 K in ambient air. The superior high-temperature characteristics are closely related to such factors as (1) the in-situ eutectic composite having a microstructure, in which single crystal Al2O3 and single crystal YAG are three-dimensionally and continuously connected and finely entangled without grain boundaries and (2) no amorphous phase is formed at the interface between the Al2O3 and the YAG phases.     

Cadmium suppresses delta 9 desaturase activity in rat hepatocytes

This paper challenges contemporary portrayals in the nursing literature of the spaces within which care of patients in hospital settings is conducted. Within the wider discourse of fiscal restraint on health care spending, professional nursing has cast its disciplined eyes on details of the nurse-patient relationship for the ostensible purpose of repairing that which is treated as individual failings of nurses to practice in ways prescribed by nursing theories. Set aside in this approach to the so-called 'problems' of nursing practice has been an examination of the conditions within which nurses come in contact with patients, and a critical recognition that such contacts represent skilled accomplishments of social action. In this paper, these conditions are treated as resources available to both nurses and patients to generate accounts for the nurse's presence as well as the nurse's absence. Examples from an ethnographic study of nursing practice are used to illustrate how the spaces operating between nurses and patients are not empty voids but are social spaces through which particular meanings about nursing care can be conveyed.     

Production of flexible metal matrix composites reinforced with continuous Si-Ti-C-O fibers by atmospheric plasma spraying

An investigation of the production of aluminum matrix composite sheet reinforced with continuous Si-Ti-C-O fibers was performed by a plasma spraying method. The unidirectionally reinforced Si-Ti-C-O fiber/Al prepreg sheet (300 by 3000 mm, 0.1 to 0.15 mm thick, with 40 vol. % Fiber) was fabricated by plasma spraying under atmospheric conditions. The depth of the oxidation layer formed on the surface of the metal matrix composite (MMC) prepreg sheet was found to be about 200 Å, and this value is almost independent of the atmosphere during plasma spraying. The fibers homogeneously disperse and do not contact each other in the matrix of the MMC prepreg. No damage on the surface of the extracted fibers from the MMC prepreg sheet can be observed. The MMC prepreg sheet was used to produce MMC plate by hot pressing at 640 to 680 °C under 9.8 MPa. The flexural strengths in the longitudinal and transverse directions of the MMC plate pressed at 660 °C were 1.0 and 0.25 GPa, respectively.     

Development of Divertor Plasma Simulators with High Heat Flux Plasmas and its Application to Nuclear Fusion Study: A Review

This overview describes recent studies of nuclear fusion by using divertor plasma simulators generating high heat flux plasma. The experimental results regarding plasma-material interaction related to tungsten and carbon dusts, and detached recombining plasma are reviewed. © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Investigation on the Interactions between Self-Assembled β-Sheet Peptide Nanofibers and Model Cell Membranes

Self-assembled peptide nanofibers (NFs) obtained from β-sheet peptides conjugated with drugs, including antigenic peptides, have recently attracted significant attention. However, extensive studies on the interactions of β-sheet peptide NFs with model cell membranes have not been reported. In this study, we investigated the interactions between three types of NFs, composed of PEG-peptide conjugates with different ethylene glycol (EG) lengths (6-, 12- and 24-mer), and dipalmitoylphosphatidylcholine (DPPC) Langmuir membranes. When increasing the EG chain length, those interactions significantly decreased considering measurements in the presence of the NFs of: (i) changes in surface pressure of the DPPC Langmuir monolayers and (ii) surface pressure–area (π–A) compression isotherms of DPPC. Because the observed trend was similar to the EG length dependency with regard to cellular association and cytotoxicity of the NFs that was reported previously, the interaction of NFs with phospholipid membranes represented a crucial factor to determine the cellular association and toxicity of the NFs. In contrast to NFs, no changes were observed with varying EG chain length on the interaction of the building block peptide with the DPPC membrane. The results obtained herein can provide a design guideline on the formulation of β-sheet peptide NFs, which may broaden its potential.     

Study of the properties of nickel oxide and nickel as precursors for the tartaric acid-NaBr-modified nickel catalyst

Nickel oxide was prepared by the decomposition of nickel hydroxide and then the nickel oxide was reduced to form the nickel catalyst. The properties of the nickel oxide and the reduced nickel were studied in relation to the enantio-differentiating ability (e.d.a.) of a tartaric acid-NaBr-modified reduced nickel catalyst. The modified nickel catalyst prepared from nickel oxide with less non-stoichiometric oxygen produced a high e.d.a. for the hydrogenation of methyl acetoacetate. The high crystallinity of the nickel oxide and the resultant nickel would be required to attain a high e.d.a.