Thailand is located in the Asia monsoon region. It has been thought that the climate change in Thailand has an impact over the global climate change, and the research on its change is very important to understand the global climate change. GPS observations have been performed at some stations to investigate the progress of monsoon in Thailand. GPS data were processed to obtain the precipitable water vapor (PWV) at Bangkok, Chiang Mai, Khon Kaen, KogMa and Phuket between 2001 and 2006.
The obtained PWVs show high values in the wet season and low ones in the dry season except for Phuket. There were some rainfalls in November and December in the dry season in 2002 and 2005, during which PWV values were also higher than those in other years. When compared with air pressure and temperature at the observation stations, positive relation between PWV and temperature was obtained for all stations except for Phuket.
Onset and offset times of the monsoon were estimated from obtained PWV values. These dates were comparatively better than those obtained from rainfall data.
We investigated grain growth process of quartz aggregates in agate. The agate samples were annealed in a piston-cylinder solid medium apparatus (MK65S) of Shizuoka University. The experiments were performed at temperature of 800°C, confining pressure of 0.5 GPa for 0.5 hr, 24 hr and 66 hr, respectively. The agates were well crystallized during experiments. Mean grain sizes increased from a few to ten microns with increasing time. Aspect ratios were nearly constant at around 0.7 (b/a; b < a). Shape preferred orientation (SPO) of quartz grains were developed with increasing time. Crystal-preferred orientation of c-axes, which were primarily girdled, appears to control the development of SPO with time.
We investigated grain growth process of quartz aggregates in flint. The agate samples were annealed in a piston-cylinder solid medium apparatus (MK65S) of Shizuoka University. The experiments were performed at temperature of 800°C, confining pressure of 1 GPa for 8 hr, 12 hr and 36 hr, respectively. The flints were well crystallized during experiments. Mean grain sizes increased from 1 to 5 µm with increasing time. Aspect ratios were nearly constant at around 0.7 (b/a; b < a). Neither shape preferred orientation nor crystal-preferred orientation of quartz grains occurred with increasing time. Comparing with grain growth experiments for agate in previous studies, the grain growth rate of quartz in flint was faster than that of quartz in agate.
Elastic wave velocities were measured on a deep seafloor serpentinite sample at room temperature and confining pressures of up to 180 MPa, using a high-pressure apparatus at University of Toyama. The sample was collected from a dredge site D17 at the Godzilla Megamullion, Parece Vela Rift, Phillipine Sea during the cruise KR07-02 (R/V Kairei). The serpentinite sample has the density of 2.37 g/cm3 and consists mainly of lizardite, chrysotile and magnetite, showing a banded structure with a moderately developed lineation and foliation. Mutually orthogonal axes were set for velocity measurements; the x-axis is parallel to the lineation, and the z-axis normal to the foliation. Lizardite mainly has a mesh texture, whereas fibrous chrysotile fills veins, most of which are subperpendicular to the lineation. The compressional wave velocity at 180 MPa is the fastest (4.56 km/s) in the y-axis direction, the slowest (3.97 km) in the direction parallel to the lineation (x-axis direction), and intermediate (4.25 km/s) normal to the foliation (z-axis direction). The azimuthal anisotropy is 13.85% at 180 MPa. The shear wave velocity at 180 MPa is 2.07~2.35 km/s. The shear waves oscillating parallel to the yz-plane have the fastest velocity, and that normal to the yz-plane the slowest. The polarization anisotropy is thus strong along the y- (9.35%) and z- (12.24%) axes, whereas weak along the x-axis (1.39%). Based on microstructural examinations, observed velocity anisotropy may be mainly controlled by the orientation of chrysotile veins rather than the banded structure.
Neogene benthic foraminifererid Lepidocyclina (Nephrolepidina) japonica was newly found from the Odaira Mudstone of the Odaira Group in Iwata City. Lepidocyclina (N.) japonica specimens obtained from the locality can be readily extracted from the mudstone. Associated planktonic foraminifera collected from the locality indicates Zone N8 of the lowest Middle Miocene Stage. In the western area of Shizuoka Prefecture, L. (N.) japonica is also known from the Zone N8 horizon of the Saigo Group and the Megami Formation. The present discovery provides a new insight into chronology and stratigraphy of the Neogene System in this area.
A new inlet system for the preparation of SF6 gas by fluorination of sulfide minerals, suitable for both in-situ laser ablation and powder samples, was connected to the existing CO2 inlet system of the Finnigan MAT-251 mass spectrometer at Shizuoka University. The preparation line is composed of a fluorine generator, two types of reaction chambers, capacitance manometer, KBr canister and liquid nitrogen slush connected by pneumatic bellows valves. It also includes a working standard SF6 gas reservoir and a machine standard SF6 gas reservoir for routine analyses. The preparation line can hold high vacuum conditions without appreciable leaks for intervals more than that required to complete one sample measurement. For simultaneous measurement of , ,  and  isotopes of SF5+, we have renovated Faraday collectors by reducing its body thickness from 4.5 mm to 3.5 mm and realigned the collector configuration of the mass spectrometer. Preliminary results of δ34S values for working standard SF6 gas gave high precession of ±0.003‰ . Further modifications in the collector assembly are in progress for the simultaneous measurement of the closely spaced ion trajectory of ,  and  isotopes of SF5+.
A new experimental method is presented in obtaining the center-of-buoyancy of Nautilus, and its physical reasoning is explained. Before experiment a model of Nautilus of uniform density is prepared, the shape of which copied exactly the lateral halves. The experiment starts with finding its balance-line with to explore on the flat plane corresponding to the animal symmetry. After the placement of the model on two isolated sticks, these were slowly brought close to each other. Ultimately these adjoin at the balance-line. Finding additional two balance-lines on the same plane will result in an intersection point, which corresponds to the center-of-gravity of the model. The intersection corresponds to the center-of-buoyancy of Nautilus. The validity of the present method is confirmed using another model, the center-of-buoyancy of which is able to explore theoretically.
The Spiral Shell Form was developed as an original computer software package designed for theoretical morphological analysis of gastropod shell forms using the Raup’s model. It is composed of the following three programs. Spiral Shell Measure is a software for capturing coordinate data of the points of interest on computer image files of a specimen. Raup’s Parameter Calculator is a Mathematica program for calculation of Raupʼs parameters from coordinate data that were collected using the Spiral Shell Measure. Spiral Shell Properties is a Mathematica program for computing physical properties of a theoretical model such as shell volume, area of the aperture, center of gravity, soft-body ratio and length of trajectory of centroid of aperture.