Statistico-Thermodynamical Studies on the Fundamental Reactions concerning Steel-Making. IV : The Oxidation and Reduction Equilibrium of Magnetite with Gas Phases

It is known that magnetite crystals can contain excess oxygen over the stoichiometric composition of Fe_3O_4 by high temperature oxidation, and the oxygen content depends on the oxygen pressure in atmosphere and on the temperature. The Fe_3O_4 crystal has a crystal structure of the inversed-spinel type, in which O^ ions occupy the closed packed cubic lattice points, and the tetrahedral lattice sites (8 f) of its unit cell are occupied by 8 Fe^ ions, and octahedral lattice sites (16 c) by 8 Fe^ and 8 Fe^ ions statistically. When the magnetite crystal contains excess oxygen under an oxidizing atmosphere, it can be assumed that a vacant site accompanying two electron defects which result in two Fe^ ions is found on the octahedral lattice points occupied by Fe^ ions. Under these circumstances we can calculate the partition function of magnetite phase, from which the equilibrium relation between the oxygen content in magnetite, the partial pressure of oxygen in atmosphere and the temperature is deduced theoretically. These results are in good agreement with observations by Greig et al. and Darken and Gurry

Statistico-Thermodynamical Studies on the Fundamental Reactions concerning Steel-Making. V : The Oxidation and Reduction Equilibrium of Mn-wustite (Fe, Mn) O with Gas Phase

It is known that Mn-wustite (Fe, Mn) O takes a from of solid solution over all compositions of Fe- and Mn-atoms, and its oxygen content varies with oxygen pressure in the thermal equilibrium and with temperature. So we examined the quantitative relation between the solid and gas phases in the above-mentioned system. Taking into consideration the previous papers in which wustite and magnetite solid solutions were discussed, a configurational model for the Mn-wustite was assumed as follows : (1) O^ and metal ions are arranged on the lattice of NaCl type, (2) in the negative ion lattice-sites O^ ions are perfectly packed, (3) in the positive ion sites Fe^, Mn^ and vacancies are randomly distributed, and (4) on some of Fe^ ions the electron-defects are trapped, producing Fe^ so that the total electrical charge of crystal is neutralized. Considering such a model, the partition function of Mn-wustite was formulated on the base of statistical thermodynamics, and the equilibrium relation between the solid composition and oxygen pressure in the gas phase was calculated. The calculated result was in agreement with the experimental values by Matoba and Gunji (1954) and our data obtained by repeated measurements of weight change using a spring balance

Production of overdense plasmas by launching 2,45 GHz electron cyclotron waves in a helical device

For production of low temperature plasmas with low collisionality, 2.45GHz microwave power up to 20kW is injected perpendicularly to the toroidal field at very low toroidal field BtComment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Characteristics of physicians, their migration patterns and distance: a longitudinal study in Hiroshima, Japan

Introduction: Although some characteristics of physicians are known to be associated with their recruitment in rural and remote areas, the factors that predict mobility of physicians, and in particular, their mobility to rural and distant areas are largely unknown. Methods: Flows of all physicians (n=4268) among municipalities in Hiroshima Prefecture, Japan, between 2002 and 2008 were analysed. Physician data were obtained from the National Physician Census. Municipality-level population data derived from the National Basic Resident Register were merged with the physician data. Information on the road distances of two municipalities measured with a geographic information system (GIS) was added to the physician cohort. Results: During the period of study, 24.8% of physicians crossed municipal borders, and among them, 66.6% moved distances of less than 60 min travel time. The number of migrated physicians decreased as the distance increased, which held true for both migration to urban and rural areas. In the univariate analysis, female, younger, and hospital physicians were more mobile to rural areas than were male, older, and clinic physicians. Male and younger (≤40 years) physicians moved a longer distance than female and older physicians. Multivariate analysis revealed that age was a negative predictor (odds ratio [OR] per 10 years 0.62, 95% confidence interval [CI] 0.55-0.70]), and affiliation with a hospital was a positive predictor of migration to rural areas (OR 6.19 [95% CI 4.21-9.10]). Male sex (OR 1.67 [95% CI 1.11-2.50]) and hospital affiliation (OR 5.61 [95% CI 3.33-9.45]) were positive predictors, and age (OR per 10 years 0.39 [95% CI 0.33-0.46]) was a negative predictor of migrating a long distance. Conclusion: In order to attract physicians to rural and remote areas, health workforce policies need to set a target population of physicians who are highly mobile to such places. Combining known predictors of rural practice, such as physicians with rural background and primary care physicians, and the mobility predictors shown in this study (ie young, hospital and male physicians) would make the target more appropriate and policies more effective.The Ministry of Education, Culture, Sports, Science and Technology (Tokyo, Japan) and Satake Education and Research Fund (Hiroshima, Japan) sponsored this research

Statistico-Thermodynamical Studies on Fundamental Reactions concerning Steel-Making. VI : On the Configuration of Fe-O Molten Slag and its Interation with Gaseous Oxygen

The iron and oxygen atom-ratio of Fe-O melts is continuously variable by the change of oxygen pressure in the gaseous phase. It is very reasonable that we suppose Fe-O melts are constructed by ionic components Fe^, Fe^ and O^, thanks to the previous results on Fe-O solid-solution phases (ref. previous Reports II and IV) and the electro-conductivity of melts. We assume the following configurational model for Fe-O molten system : (1) Oxygen ions O^ are arranged on the face-centered cubic lattice (nearly close-packed), because they are very large compared with iron ions. (2) Fe^ ions are distributed on the tetrahedral and octahedral interstitial lattice points of the oxygen-ion lattice. (3) If any tetrahedral lattice point is occupied by a iron ion, its nearest octahedral lattice points are vacant, and it is the same for the nearest neighbors of octahedral iron ions. (4) Positive holes are randomly distributed on Fe^ ions, and thus Fe^ ions are formed. Using the above model the partition function of the Fe-O molten slag was formulated by the statistical thermodynamic method, and the equilibrium relation between the slag composition and the pressure of oxygen in gas phase was calculated. These theoretical results are in good agreement with the measured values of Darken and Gurry (1946) in the wide range of pressure, 10^ to 1 atm of O_2, and temperature 1400°to 1600℃

An empirical examination of the mechanisms mediating between high performance work systems and the performance of Japanese organizations

The resource-based view of the firm and social exchange perspectives are invoked to hypothesize linkages among high-performance work systems, collective human capital, the degree of social exchange in an establishment, and establishment performance. The authors argue that high-performance work systems generate a high level of collective human capital and encourage a high degree of social exchange within an organization, and that these are positively related to the organization’s overall performance. On the basis of a sample of Japanese establishments, the results provide support for the existence of these mediating mechanisms through which high-performance work systems affect overall establishment performance

Chromatographic formation of a triadic band of lithium in hydrated LTA zeolite: An investigation on lithium isotope separation effects by ion exchange

published online 12 April 2017Lithium concentrations [Li] and isotopic ratios [Li-7]/[Li-6] were measured for effluent fractions from a biphasic zeolite column. The biphasic state was ascribed to a mixture of hydrated Linde Type A (LTA) zeolites, [Li-0.008(NH4)(0.92)]A and [Li-0.33(NH4)(0.67)]A, which were formed by Li ion exchange from hydrated ammonium in the form (NH4)(12)[Al12Si12O48]center dot nH(2)O (NH(4)A). The biphasic Li band of the column was displaced by ion exchange with a solution of NH4NO3. A constant [Li] with a much lower level than the concentration of NHt(4)(_)(+) in the displacer (NH4NO3) was observed for the effluent from a short column. This constant lower level of [Li] was attributable to the biphasic state. On this [Li] plateau of the effluent, the level of [Li-7] shifted higher than the original isotopic composition of the Li feed, whereas Li-6 was concentrated on the biphasic zeolite solid. The accumulation of Li-6 in the zeolite proceeded by a mechanism of differential elution of Li-7 from the biphasic zeolite. For the long column experiment, a significant enrichment of Li-6 in the zeolite was observed, whereby a triadic band of Li was probably formed in the column. Two monophasic and a biphasic state were assigned. The biphasic band was deemed to push the monophasic bands forward, thereby enriching the monophasic bands with Li-7, while Li-6 accumulated at the end of the biphasic band. The trio structure of the Li band and isotopic discrimination in the band were analyzed. (C) 2017 Elsevier Inc. All rights reserved.ArticleMICROPOROUS AND MESOPOROUS MATERIALS. 248:115-121 (2017)journal articl