On the Concentrations of the Dissolved Chemical Elements in the Estuary Water of the Chikugogawa River

When river water mixes with sea water in estuary area, the concentrations of the dissolved element in river water may be changed by either a simple physical mixing process or some complex chemical processes. It has been clarified in the Chikugogawa River estuary area that the change in concentrations of SO ₄ ²⁻ , BO ₃ ³⁻ , Mg²⁺, Ca²⁺ and F⁻ is only due to the mixing process but the change in concentrations of SiO ₃ ²⁻ and Al³⁺ is due to the chemical process in addition to the mixing process.      

Melting of iron–silicon alloy up to the core–mantle boundary pressure: implications to the thermal structure of the Earth’s core

The melting temperature of Fe–18 wt% Si alloy was determined up to 119 GPa based on a change of laser heating efficiency and the texture of the recovered samples in the laser-heated diamond anvil cell experiments. We have also investigated the subsolidus phase relations of Fe–18 wt% Si alloy by the in-situ X-ray diffraction method and confirmed that the bcc phase is stable at least up to 57 GPa and high temperature. The melting curve of the alloy was fitted by the Simon’s equation, P(GPa)/a = (T _m(K)/T ₀) ^c , with parameters, T ₀ = 1,473 K, a = 3.5 ± 1.1 GPa, and c = 4.5 ± 0.4. The melting temperature of bcc Fe–18 wt% Si alloy is comparable with that of pure iron in the pressure range of this work. The melting temperature of Fe–18 wt% Si alloy is estimated to be 3,300–3,500 K at 135 GPa, and 4,000–4,200 K at around 330 GPa, which may provide the lower bound of the temperatures at the core–mantle boundary and the inner core–outer core boundary if the light element in the core is silicon.     

A simple parameterization of longwave radiative cooling with application to the atmospheric boundary layer for clear sky conditions

A simple parameterization is proposed to obtain longwave radiative cooling rates, which can be used for atmospheric boundary-layer simulations on clear days in mid-latitudes. The net flux difference which is set to zero at the surface, can be parameterized with the use of three variables: the surface temperature, the lowest level (1.5 m) air temperature, and the total amount of water vapor. If these three elements, along with the water vapor profile are known, it is possible to estimate the cooling rate due to longwave radiation. The results of this parameterization are in good agreement with those of a precise scheme (Roach and Slingo, 1979), within a range of ± 1°C/day of diurnal change for boundary-layer simulations.     

Synchrotron radiation study on the high-pressure and high-temperature phase relations of KAlSi3O8

In situ X-ray diffraction study on KAlSi₃O₈ has been performed using the cubic type high pressure apparatus, MAX90, combined with synchrotron radiation. We determined the phase relations of sanidine, the wadeite-type K₂Si₄O₉+kyanite (Al₂SiO₅)+coesite (SiO₂) assemblage, and hollandite-type KAlSi₃O₈, including melting temperatures of potassic phases, up to 11 GPa. Our data on subsolidus phase boundaries are close to the recent data of Yagi and Akaogi (1991). Melting relations of sanidine are consistent with the low pressure data of Lindsley (1966). The breakdown of sanidine into three phases reduces melting temperature, and wadeite-type K₂Si₄O₉ melts first around 1500° C in three phase coexisting region. Melting point of hollandite-type KAlSi₃O₈ is between 1700° C and 1800° C at 11 GPa. If these potassic phases host potassium in the earth's mantle, the true mantle solidus temperature will be much lower than the reported dry solidus temperature of peridotite.     

Equation of state of iron–silicon alloys to megabar pressure

The stability and pressure–volume equation of state of iron–silicon alloys, Fe-8.7 wt% Si and Fe-17.8 wt% Si, have been investigated using diamond-anvil cell techniques up to 196 and 124 GPa, respectively. Angular–dispersive X-ray diffractions of iron–silicon alloys were measured at room temperature using monochromatic synchrotron radiation and an imaging plate (IP). A bcc–Fe-8.7 wt% Si transformed to hcp structure at around 1636 GPa. The high-pressure phase of Fe-8.7 wt% Si with hexagonal close-packed (hcp) structure was found to be stable up to 196 GPa and no phase transition of bcc–Fe-17.8 wt% Si was observed up to 124 GPa. The pressure–volume data were fitted to a third-order Birch–Murnaghan equation of state (BM EOS) with zero–pressure parameters: V₀=22.2(8) ų, K₀=198(9) GPa, and K₀=4.7(3) for hcp–Fe-8.7 wt% Si and V₀=179.41(45) ų, K₀=207(15) GPa and K₀=5.1(6) for Fe-17.8 wt% Si. The density and bulk sound velocity of hcp–Fe-8.7 wt% Si indicate that the inner core could contain 3–5 wt% Si.     

Aircraft measurements of oxides of nitrogen along the eastern rim of the Asian continent: Winter observations

Aircraft observations of oxides of nitrogen (NO _y ), measured with a ferrous sulfate converter, over the sea surrounding the Japanese islands (30–43° N, 131–141° E) were carried out in the winter of 1983 and 1984 at altitudes mostly between 3 and 8 km. NO _y defined here is the sum of NO, NO₂, and other unstable oxides of nitrogen that are converted to NO by ferrous sulfate. The main observations were:

1. Over the Pacific Ocean between the latitudes of 30–35° N, the observed NO _y mixing ratio between 3 and 8 km was a fairly constant 200 pptv. The NO mixing ratio increased with altitude from 15 pptv at 3 km to 35 pptv at 7 km.
2. Over the Sea of Japan, tropospheric NO _y mesured between 1 and 6 km started increasing with latitude North of 35° N and reached about 1000 pptv at 40° N.
3. NO _y was measured in an air mass transported from the stratosphere near a tropopause fold region. When the ozone mixing ratio was between 80 and 140 ppbv, the NO _y mixing ratio was about 200 pptv.

     

The selectivity of the Ioannina VAN station

Two peculiar characteristics of the VAN method of short-term earthquake prediction are: (1) the existence of sensitive and insensitive sites to seismic electric signal (SES) and (2) the selective sensitivity of a sensitive station to SES from specific focal area(s). The process of their discovery, which so far has not been published adequately, is examined for the Ioannina (IOA) station. The sensitive site was discovered simply through repeatedly moving the temporary observation network. The selectivity map of the IOA station was made by first identifying the earthquake source areas with SESs which were considered to have been detected at IOA, and second by examining the direction of SESs from different such source areas. For the latter purpose, information from long dipoles appears to have been helpful. The selectivity map is empirically constructed and is updated regularly. We have independently tried to construct a selectivity map of IOA by examining VAN's raw SES records and by using the same criteria as VAN. The selectivity map we obtained was not exactly, but roughly similar to that of VAN.     

On the mass-luminosity relation

The results of a least-squares study of the mass-luminosity relation for eclipsing and visual binary stars consisting of main sequence components are presented. Two methods are discussed. In Part A, the values of the coefficientsA andB in the relation logM=A+BM _Bol are determined. Part B presents a technique which permits the determination of α and β in the relationM=αL ^β, when only the sum of the masses, and not the individual masses of each component, is known. The results and a comparison of the two methods are discussed. It is found that the following massluminosity relation represents the observational data satisfactorily: $$log M = 0.504 - 0.103M_{BOL,} {\text{ }} - \leqslant M_{BOL} \leqslant + 10.5$$ . A discussion of the data and of the possibility that separate mass-luminosity relations may exist for visual and eclipsing binaries is given. The possiblity that more than one mass-luminosity relation is required in the range ?8≤M _Bol ≤+13 is also discussed.