Phase Relations and Volume Changes of Hafnia under High Pressure and High Temperature

Using multi-anvil high-pressure devices and synchrotron radiation, X-ray in situ observations of HfO₂ under high pressure and high temperature have been performed to investigate its phase relations and compression behavior. An orthorhombic phase (orthoI) is stable from 4 to 14.5 GPa below 1250°–1400°C and transforms to a tetragonal phase, which is one of the high-temperature forms of HfO₂, above these temperatures. Another orthorhombic phase (orthoII) with a cotunnite-type structure appears above 14.5 GPa. OrthoII is stable up to 1800°C at 21 GPa. OrthoII is quenchable to ambient conditions. The orthoI-to-orthoII transition is accompanied by ∼8 vol% decrease. The bulk moduli of orthoI and orthoII at room temperature are 220 and 312 GPa, respectively. This low compressibility of orthoII indicates that it is a potential candidate for very hard materials.     

Reappraisal of loading rate effects on sand behavior in view of seismic design for pile foundation

This study re-visits the effects of loading rate on sand behavior in view of seismic design of pile foundation. Based on an extensive literature review covering both element testing and model testing, the paper summarizes the current understanding of the loading rate effects. The paper then describes the development of test apparatus used in this study and presents the data obtained from a series of monotonically increasing triaxial compression tests on Toyoura sand, varying the strain rate in the range of 0.005%/s to 250%/s. A total of 36 tests were conducted on dry and saturated sand, both under drained and undrained conditions with two confining pressures. The experimental results confirm that the soil strength and the soil stiffness increase as the strain rate increase. This paper also concludes that the internal friction angle and deformation modulus increase when the strain rate is high. The implications of the loading rate effect on pile foundation design are then presented.     

Advantage of Sodium Polyoxyethylene Lauryl Ether Carboxylate as a Mild Cleansing Agent

Five anionic surfactants widely used in commercial skin cleansers were studied: sodium polyoxyethylene lauryl ether carboxylate (EC), sodium polyoxyethylene alkyl ether sulfate (ES), sodium dodecyl sulfate, potassium laurate, and N-cocoyl-l-glutamic acid monosodium salt. The amount of surfactant from aqueous solution adsorbed into the stratum corneum (SC), the degree of SC swelling, the change of the secondary structure of SC proteins (denaturation). The surface tension of surfactant–zein mixed solutions, and the solubilization behavior of zein were measured. Results showed that EC had the lowest adsorption into SC, the lowest SC swelling, and lowest denaturation of SC proteins. Low interactions between surfactants and SC proteins were also observed for EC/ES mixture solutions as well as. Mixing EC with ES good foaming performance. The EC/ES mixture, at about 1:1 ratio, is an excellent surfactant system for skin cleanser applications having cleansing characteristics and mildness to the skin.     

Surface Analysis of Cr2O3‐, CoO‐, and Al2O3‐Doped Iron–Phosphate Glasses at High Temperature

Surface structures of iron–phosphate glasses were examined using X‐ray photoelectron spectroscopy (XPS). Cr₂O₃, CoO, and Al₂O₃ were introduced to the glass by the replacement of a part of Fe₂O₃, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC‐1 test. In situ high‐temperature and room‐temperature XPS measurements were conducted on the polished sample surfaces and also those after 1‐week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron–phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition‐metal ions.     

Structure and Properties of Endosperm Starch and Water Soluble Polysaccharides from Sugary Mutant of Rice (Oryza sativa L.)

Structure and properties of starch and water soluble polysaccharides (WSP) from sugary (su) endosperm of rice were examined. The su starch contained more amylose and had a somewhat higher ratio of the short chains to the long chains of amylopectin than normal starch. The WSP consisted of short α-1, 4-chains and their average degree of polymerization was 8.6 glucose units. Susceptibility of the su starch to crude Rh. glucoamylase was higher than that of the normal. The initial and final temperatures and heat of gelatinization of the su starch granules were much lower than those of the normal ones.     

Basic information on new regulatory criteria requiring on-site emergency preparedness for accelerator facilities in Japan

For basic information on new regulatory criteria, the dose rate around a thick target bombarded by proton, electron, or carbon beam having incident energy of 10 MeV–50 GeV (per nucleon in case of carbon) was simulated using the PHITS Monte Carlo code. Based on this simulation, the benchmark which is ‘1 Sv/h at 1 m away from the beam line’ assuming 1% beam loss was evaluated, and compared with the criteria in France and Canada. Based on this evaluation, a new regulatory criteria has been established for requiring on-site emergency preparedness for accelerator facilities in Japan, which is required for the ion accelerator beyond the ion beam of 100 MeV/nucleon and 0.5 kW beam power, and the electron accelerator beyond the electron beam of 50 MeV energy and 1 kW beam power.     

Wave venation in downward gas-liquid two-phase flow (part I,time-spatial behavior chart of interface and analysis of main wave-vein)

Time-series information on both the cross-sectional mean liquid holdup along a tube axis and the gas-liquid phase distribution along a tube diameter was obtained by means of supermultiple cross-sectional mean liquid holdup probes (S-CHOP) and semi-supermultiple point-electrode probes (SS-PEP) for vertical downward gas-liquid two-phase flow. Typical time-spatial behavior charts of interface and gas-liquid interfacial profiles are presented. Close inspection of these results reveals that a huge wave and a disturbance wave appear in downward two-phase flow as well as upward flow. It was clarified that the huge wave flow region covers a wide range of superficial gas velocities. Wave velocity, wave width and maximum liquid holdup of individual waves were examined by wave-vein analysis. Histograms of these flow parameters were also studied. It was found that there exist distinct differences in wave width between the huge wave and the disturbance wave. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(8): 499–510, 1996     

Characteristics of interfacial profiles in upward and downward gas-liquid two-phase plug flow

Gas-liquid interfacial profiles in plug flow for both upward and downward flows were obtained using semi-supermultiple point-electrode probes, comprising 67 sensing tips arranged on a tube diameter. Typical interfacial profiles are demonstrated for both flows. Close inspection of the profiles reveals that four zones exist in a pair of gas and liquid slugs for upward plug flow and a high slip velocity region in downward plug flow. The lengths of the swelling liquid front zone and the wake zone were determined. The length of the wake zone strongly depends on the relative velocity between the liquid film around the gas slug and the liquid phase in the liquid slug. Characteristic distributions of bubbles within liquid slugs were found, i.e., three types of radial distributions of void fraction, namely saddle-shaped, trapezoidal and bullet-shaped distributions, exist for upward flow. The two types for downward flow exclude the saddle-shaped distribution. © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25 (8): 568–579, 1996