The chemical composition and nickel,cobalt, copper,zinc and lead contents of Nanao Bay sediments

The contents of major and some of the minor elements, nickel, cobalt, copper, zinc and lead were studied on sediments collected from three inlets of Nanao Bay located at eastern side of Noto Peninsula. Little variation was found on the average contents of silicon, iron, titanium, aluminum, manganese, magnesium and potassium among the sediments of West, South and North Bays in Nanao Bay. Whereas significant difference was found on the contents of calcium, chlorine, sulfur and nitrogen among sediments of three bays.As to the minor elements, the average contents of nickel (20±5 ppm), cobalt (5±1 ppm), copper (18±5 ppm) and lead (17±8 ppm) are relatively low but zinc content is high in these sediments comparing with those of coastal deposit around Japan Island. From the results obtained here, it became clear that no environmental contamination of nickel, cobalt, copper and lead, and a little organic pollution were found in Nanao Bay sediments.     

Earthquake‐related geomorphic environment and pond sediment information

Shaking during the 1995 Kobe earthquake caused surface material to be more mobile in catchment areas in the Rokko Mountains, Kobe, where there are some active fault lines. As a result, there were many landslides associated with the earthquake. The sedimentation rate in a pond in the mountains increased several fold, then exponentially decreased with seasonality over several years. Six years after the earthquake there were no marked surface movements related to the earthquake, even though the sedimentation rates had increased slightly. A new steady state for the structure of the earthquake‐modi?ed surface had evidently been reached. Copyright © 2004 John Wiley & Sons, Ltd.     

Air/water two-phase flow test tunnel for airfoil studies

A test tunnel for the study of airfoil performances under air/water two-phase flow condition has been designed and constructed. This facility will serve for a better understanding of the flow phenomena and characteristics of hydraulic machinery under gas/ liquid two-phase flow operating conditions. At the test section of the tunnel, a two-dimensional isolated airfoil or a cascade of airfoils is installed in a two-phase inlet flow with a uniform velocity (up to 10 m/s) and void fraction (up to 12%) distribution. The details of the tunnel structure and the measuring systems are described and the basic characteristics of the constructed tunnel are also given. As an example of the test results, void fraction distribution around a test airfoil is shown.Dedicated to the 60th Birthday of Professor Klaus Gersten     

Polysynthetically-twinned structures of enstatite and wollastonite

Crystal structures of clinoenstatite, orthoenstatite, wollastonite-1T and wollastonite-2M (parawollastonite) were refined to an R factor 3–4 percent level. Molar volumes at room temperature are 31.270(15), 31.315(8), 39.842(5) and 39.901(10) cm³/MSiO₃, in the above-mentioned order, indicating that one-layer polytypes (clinoenstatite and wollastonite-1T) are stable at higher pressures than two-layer polytypes (orthoenstatite and wollastonite-2M). The polytypic relation of the enstatite polytypes can be described by four twinning operations — b glide ∥ to (110), a glide ∥ to (001), twofold screw axis ∥ to a (of orthoenstatite) and a twofold screw axis ∥ to c. For the wollastonite polytypes, twinning operations are twofold screw axis ∥ to b and a glide ∥ to (010). Structural adjustments after twinning are not necessarily the largest at the twin boundary (true in enstatite but not so in wollastonite). In both cases octahedral sites that involve bridging oxygens tend to show relatively large changes. Lattice strain ellipsoids associated with twinning are also different for enstatite and wollastonite, which implies that wollastonite may react differently from enstatite to non-hydrostatic pressure.     

The distribution of Fe3+ and Ga3+ between two tetrahedral sites in melilites,Ca2(Mg,Fe3+, Ga,Si)3O7

The distribution of Fe³⁺ and Ga³⁺ between the two tetrahedral sites in three synthetic melilites has been studied by using ⁵⁷Fe Mössbauer spectroscopy. In the melilite, (Ca₂Ga₂SiO₇)₅₀ (Ca₂Fe³⁺GaSiO₇)₅₀ (mol %), the distribution of Fe³⁺ and Ga³⁺ in T1 and T2 sites is apparently random, which can be explained in terms of the electrostatic valence rule. However in the melilites, (Ca₂MgSi₂O₇)₅₂ (Ca₂Fe³⁺GaSiO₇)₄₂ (Ca₂Ga₂SiO₇)₆ and (Ca₂MgSi₂O₇)₆₂ (Ca₂Fe³⁺GaSiO₇)₃₆ (Ca₂Ga₂SiO₇)₂ (mol %), Fe³⁺ shows preference for the more ionic T1 site and Ga³⁺ for the more covalent T2 site. If the electronegativity of Ga³⁺ is assumed to be larger than that of Fe³⁺, the mode of distribution of Fe³⁺ and Ga³⁺ can be explained in terms of our previous hypothesis that a large electronegativity induces a stronger preference for the more covalent T2 site.     

Comparison of observed and theoretically calculated seiches of Heda Bay,Japan

We carried out observations of sea-level fluctuations simultaneously at three stations on the coast of Heda Bay, Honshu, Japan, using supersonic-type water level gauges controlled by a personal computer. Analyses of the obtained data showed predominant spectral peaks at periods of 7.6, 2.0 and 1.3 minutes for all three stations. Comparison of the observed data with numerically calculated normal oscillation modes of the bay indicates that these three spectral peaks correspond to the theoretical first, third and seventh normal modes of the basin respectively, judging from the results of cross-spectral analyses. The reason for the absence of the remaining normal modes, especially of the second or the lateral first mode of the basin, is briefly considered.     

Layered soil-pile-structure dynamic interaction

This paper is concerned with the dynamic interaction between soil, pile and structure when subjected to harmonic excitation at the base rock level. The structure to be analysed is an isolated tall bridge pier with deep group pile foundation. The dynamic substructure approach is taken, dealing first with the pile-footing substructure and the pier superstructure independently; and then integrating these at the interface. Since the soil profile is multi-layered, the transfer matrix scheme is applied to extend the relevant continuum solution proposed by earlier researchers for pile analysis in a homogeneous viscoelastic medium. Using a numerical example, the importance of the soil layer vibration modes which exert forces on the pile varying along the pile length is pointed out together with the soil-structure inertial interaction in the structural response. The latter concerns the dynamic characteristic of the complete system whereas the former relates the driving force to it. Also examined is the applicability of the approximate soil reaction based on the plane strain assumption, which simplifies the formulation and requires much less computing time in the response analysis.