Numerical Prediction of Eutectic Temperature Using a Multi-phase-Field Model

To evaluate the reliability of metal-carbon eutectic systems as fixed points for the next generation of the international temperature scale, the effect of the eutectic microstructure on the temperature at the solid/liquid (s/l) interface during solidification and melting is preliminarily investigated using a multi-phase-field model. First, the effects of furnace temperature, lamellar spacing, and interface energy on the average temperature of the s/l interface are studied in the solidification process. With increased furnace undercooling, the s/l interface temperature was found to decrease. Calculated eutectic microstructures are then adopted as initial conditions for a melting simulation. The interface undercooling during melting is observed to be smaller than that observed during solidification. This difference in interface undercooling is attributed to the solute/solvent concentration profiles in the liquid phase near the s/l interface being different for melting and solidification.     

Evaluation Of Genotoxicity Of Bromate Ion Produced During Ozonation

Bromate ion formation during ozonation processes in water works is regarded as an issue of great interest because of its potential for carcinogenicity. In this research, genotoxicity of bromate ion was investigated by the umu-test using Salmonella typhimurium TA 1535/pSK1002. The time-course study showed that the umuC gene related to error-prone repair of damaged DNA was induced by bromate ion after 12 hours exposure of the test strain. However, a further study revealed that this induction was inactivated by metabolism with rat liver microsome when bromate ion concentration was less than 0.88 mg BrO₃ ^?/mg as protein of the S9 fraction. This inactivation was assumed to depend on -SH compounds in liver microsome.     

CONTROL OF THE ENVIRONMENT THROUGH QUASI-MARKETS

ABSTRACT In this paper, we discuss an indirect mechanism which corresponds to the Vickrey auction and Clarke tax mechanisms. A message is sent to the central agency through parameterization of the valuation function. Namely, strategy spaces are parameter spaces of a certain Function through which the economic agent intends to inform the central agency of the valuation function. We also discuss the optimal control of pollution emissions, abatement activity and the quality level of the environment through the instrument of quasi-markets.     

Molybdenum Catalyzed Reactions Selectivity in Oxidations with Hydrogen Peroxide and Ammonium Molybdate

Hydrogen peroxide in conjunction with ammonium molybdate effects the epoxidation of olefins, the oxidation of secondary alcohols to ketones, and the oxidation of aldehydes to acids. By controlling pH olefin epoxidation can be suppressed in favor of alcohol oxidation. Secondary alcohols are cleanly oxidized in the presence of primary alcohols. Sterically more hindered alcohols are oxidized more rapidly than less hindered alcohols. The latter rate preference permitted selective conversion of a 17-hydroxyl group of several steroids into a.ketone in the presence of a 3-hydroxyl group. The chemoselective oxidation of aldehydes to carboxylic acids is another use of this inexpensive oxidation system. A rate acceleration by addition of the lanthanide salt cerium chloride is noted and attributed to enhanced rates of hydration of the aldehyde. Potential mechanisms are discussed.     

Investigation of TiC–C Eutectic and WC–C Peritectic High-Temperature Fixed Points

TiC–C eutectic (2,761°C) and WC–C peritectic (2,749°C) fixed points were investigated to compare their potential as high-temperature thermometric reference points. Two TiC–C and three WC–C fixed-point cells were constructed, and the melting and freezing plateaux were evaluated by means of radiation thermometry. The repeatability of the TiC–C eutectic within a day was 60 mK with a melting range roughly 200 mK. The repeatability of the melting temperature of the WC–C peritectic within 1 day was 17 mK with a melting range of ∼70 mK. The repeatability of the freezing temperature of the WC–C peritectic was 21 mK with a freezing range less than 20 mK. One of the TiC–C cells was constructed from a TiC and graphite powder mixture. The filling showed the reaction with the graphite crucible was suppressed and the ingot contained less voids, although the lack of high-purity TiC powder poses a problem. The WC–C cells were easily constructed, like metal–carbon eutectic cells, without any evident reaction with the crucible. From these results, it is concluded that the WC–C peritectic has more potential than the TiC–C eutectic as a high-temperature reference point. The investigation of the purification of the TiC–C cell during filling and the plateau observation are also reported.     

Calcium phosphate composite materials including inorganic powders,BSA or duplex DNA prepared by W/O/W interfacial reaction method

We reported before that inorganic reaction occurring at the interface of W/O/W emulsion is advantageous to produce hollow spheres (microcapsules) of inorganic matrices such as silica. This process enables us to include various materials into inorganic matrices directly. Calcium phosphates were also produced from NH₄H₂PO₄ and Ca(OH)₂ by this interfacial reaction method. Various biomaterials are directly incorporated into crystalline calcium phosphate matrices, when the biomaterials are added to the inner water phase of the W/O/W emulsion. ZrO₂ and Al₂O₃ powders were effectively encapsulated in calcium phosphates such as hydroxyapatite (HAp). The images of backscattered electron of FE–SEM observations indicated that ZrO₂ particles were included in HAp, while they adhered to the surface of HAp in the case of a simple precipitation method. Biomacromolecules such as BSA and duplex DNA were also included in HAp using the inner water phases dissolving them. Fluorescent microscopy observations revealed that biomacromolecules incorporated in HAp localized in some domains of the HAp matrices. Biomacromolecules thus included were scarcely liberated into deionized water, indicating their strong encapsulation in HAp. This general and simple methodology will provide various composite materials of calcium phosphates, which are applicable to regenerative medicine, DDS, GDS and more.     

Dynamical properties of the relaxor ferroelectric 0.71Pb(Ni1/3Nb2/3))O3-O.29PbTiO3 probed by Brillouin and Raman scattering

Abstract-Structural phase transitions in relaxor ferroelectric materials remain to be one of the most puzzling issues in materials science. In the present work, we have investigated relaxational and vibrational properties of a relaxor ferroelectric 0.71Pb(Ni(1/3)Nb(2/3))O(3)-O.29PbTiO(3) single crystal by means of inelastic light scattering measurements. Analysis based on the spectra has shown anomalous behaviors at Burns' temperature T(d), freezing temperature T(f) , those are related to a development of polar nanoregions (PNRs). The PNR must play a key role in the relaxor nature, and obtained results provide new insights into the relaxational dynamics in the PNRs and into how they develop below T(f).     

InGaAs quantum dots formed in tetrahedral-shaped recesses on GaAs (111)B grown by metalorganic chemical vapor deposition

Novel semiconductor quantum dots (QDs), grown in tetrahedral-shaped recesses (TSRs) formed on a (111)B GaAs substrate, are described from both material science and device application points of view. After explaining the fabrication procedure for TSRs, growth of InGaAs QDs and their optical properties are explained. It is revealed that an InGaAs QD of indium-rich chemical composition is formed spontaneously at the bottom of each TSR. The mechanism of the QD formation is discussed in detail. It is proved from magneto-photoluminescence that the QDs actually have optical properties peculiar to zero-dimensional confinement. Several experimental results indicating excellent growth controllability of the QDs are presented. Finally, recent challenges to apply the QDs to electronic memory devices are reported. Two kinds of devices, where the position of individual QD is artificially controlled, are proposed for the first time and the preliminary experimental results are explained.     

Production of a Novel Proanthocyanidin-free Barley Line With High Quality

A proanthocyanidin-free (ant-free) barley with improved quality, Mokkei 92–130, was bred from the cross between Ant 13–347, an ant-free mutant and Haruna Nijo, a Japanese malting barley variety. The malting and brewing quality of the line are described in this paper, while its agronomic performance will be summarised elsewhere. Mokkei 92–130 achieved high levels in some malting quality character including hot water extract, diastatic power and apparent attenuation limit, which were significantly low in most of the ant-free lines and varieties previously reported. Cell wall degradation was also improved. Overall malting quality was found to be satisfactory in Mokkei 92–130. Pilot-scale brewing trials showed that Mokkei 92–130 had superior colloidal stability (less haze formed) in its final beer compared with the normal counterparts. Beer brewed with ant-free barley at a pilot-scale performed as well as the standard production in sensory evaluations soon after bottling, although it was rated poorer than the control after one month storage at ambient temperature.