Krit Won-In

Raman spectroscopic study on archaeological glasses in Thailand: Ancient Thai Glass

Glasses have been used as ornamental and decorative objects in Thailand for several hundred years as seen in archaeological artifacts, such as glass beads found throughout the regions. Decorative glasses can generally be seen as architectural components in Buddhist temples and old-styled palaces. They came in various colors ranging from transparent to amber, blue, green and red of different shades and tones. Fragments of archaeological glass samples were characterized for the first time using Raman spectrophotometer with the aim of obtaining information that would lead to the identification of the glass samples by means of laser scattering. The samples were also investigated using other techniques, such as proton induced X-ray emission spectroscopy, scanning electron microscopy cooperated with energy dispersive X-ray fluorescence spectrometer and synchrotron radiation to induced X-ray fluorescence. The results showed that they were mostly lead-silica based glasses whose colors were induced by metal ions. The differences in chemical compositions were confirmed by Raman signature spectra.

Enhancement of thematic mapper satellite images for geological mapping of the Cho Dien area, Northern Vietnam

Abstract Information available from the earth science image processing package (ESIPP) software program was applied to enhance the satellite image data of the Cho Dien area, northern Vietnam. The area with dense vegetation covers is dominated by several small Zn–Pb prospects in middle Paleozoic limestone units. Interpretation of satellite image data using the digital enhancement ESIPP program, forms the prime objective of this study, which is to improve the image quality and visual interpretation of regional geology, lineament and structural geology. Thematic mapper of bands 7, 5 and 4 with the false-color composites: blue, green and red, respectively, are considered to be the most appropriate for geologic interpretation. Dark pixel correction is carried out prior to other enhancement analyses which include high-pass filtering, albedo correction, image classification, principle component analysis (PCA) and band ratios. High-pass filtering enhancement is considered to be the most suitable approach for lineament analysis. Albedo is good for differentiating lithology, and image classification is also successfully used for lineament interpretation and discrimination of lithologies but is regarded not better than high-pass filtering and albedo. PCA and ratio of band enhancements are considered not good because there are many disturbed and excavated land areas such as abandoned and current open pits in the concerned area. The result of Landsat interpretation indicate that most lineament structures developed in a roughly N-trending anticlinal structure are in NE-, E- and N-trends. Minor lineaments are in roughly NW-trend, and cross-cutting the NE- and E-trends. Interpretation from enhanced Landsat information also fits very well with field evidences. The interpreted map is slightly different from those of the previous mapping works, particularly with respect to detailed lithological boundaries.

Paleoearthquake Investigations of the Mae Hong Son Fault, Mae Hong Son Region, Northern Thailand

We applied remote sensing and aerial photographic techniques to a study of the Mae Hong Son Fault (MHSF), located in the Mae Hong Son region, northern Thailand. Several fault lines are recognized in the region, trending mainly NE–SW, NW–SE, and N–S. The main morphotectonic landforms associated with the MHSF are fault scarps, offset streams, linear valleys, triangular facets, offset ridge crests, hot springs, and linear mountain fronts. A trench, a quarry, and a road cut in Caenozoic strata were used to analyze fault geometries in the area. We identified eight paleoearthquake events from trenching, quarry, and road-cut data, and from optically stimulated luminescence (OSL) and thermoluminescence (TL) dating. The OSL and TL ages of the events are: (1) 78,000 yr BP; (2) 68,000 yr BP; (3) 58,000 yr BP; (4) 48,000 yr BP; (5) 38,000 yr BP; (6) 28,000 yr BP; (7) 18,000 yr BP; and (8) 8,000 yr BP. The recurrence interval of seismic events on the MHSF appears to be ca. 10,000 years, and the slip rate was estimated as ca. 0.03–0.13 mm/yr. There is a low possibility of a large earthquake on the MHSF in the near future.

Characterization of prehistorical glass beads excavated from Khao Sam Kaeo (Chumphon, Thailand) using PIXE and SEM–EDS

It was proved that non-destructive and non-sampling methods were used to analyze the composition of the archaeological glasses. Glass has been used in ornaments and decoration in Thailand for thousands of years. In this study, glass bead fragments found from the archaeological site at Khao Sam Kaeo, Chumphon Province, southern Thailand were analyzed by the proton induced X-ray emission spectroscopy (PIXE) and scanning electron microscope coupled with energy dispersive X-ray fluorescence spectroscopy (SEM–EDS). The composition analysis showed that copper was mainly presence as the colorant. Titanium, common impurity in sand, was all present in the glass bead samples. Furthermore, this type of glass almost spread over the various sites in this region that demonstrated the long distance or exchange connections. Finally, PIXE and SEM–EDS have been used to be the efficient techniques to analyze the archaeological objects, especially the glassy materials, to understand their characteristics and how they were produced in ancient times.

Nuclear analytical methods on ancient Thai rice

For more than half of humanity, rice is life. Rice is a grain which has shaped the history, culture, diet and economy of billions of people in Asia. In Thailand, it is the essence of life. Archaeological evidence revealed that rice had been planted in northeastern area of Thailand more than 5,500 years ago which is earlier than in China and India. The ancient rice grains were found in various archaeological sites in Thailand such as Nakhon Nayok, Suphan Buri and Prachin Buri Provinces. In this work, the ancient black rice from Nakhon Nayok Province was elementally analyzed using scanning electron microscope coupled with energy dispersive X-ray fluorescence spectroscopy, proton induced X-ray emission spectroscopy and micro-beam energy dispersive X-ray fluorescence spectroscopy. Infrared (IR) spectroscopy was also used to study the chemical composition and bio-molecular structure. The grains were oblique in shape with a rough surface. Three major elements (Si, Ca and Al) and other trace elements were detected. The IR spectra provided some information about the presence of molecular bonds.

PIXE study on Thai amulet: Phra Somdej Wat Rakhang

Phra Somdej Wat Rakhang amulets which were one of the most famous Thai amulets created in an image of Lord Buddha meditation. They were made to explain the Dharma of Buddha and to bless every life in this world for good karma. Their compositions contained with both inorganic and organic materials such as shell lime, assorted flowers, ashes from incense urns, etc. Various molds were differed both types and compositions. In this work, it was the first time on advanced structural analysis using non-destructive x-ray fluorescence spectrometry methods; particle induced x-ray emission. Samples were selected by various molds to analyze theirs composition. Results revealed the presence of Ca, Al, K, Si and others such as Fe, Cu, Mn and Zn. It was also found that there were differences in concentration of composition. It can be concluded that their matrices were heterogeneous. Each mold may be characterized using the differences in its composition.

X-Ray Spectrometry Study on Historical Decorative Glasses in Thailand: Lanna-Style Glass

t was known that historical objects were highly heterogeneous. Due to the complex nature of materials and objects, extremely sensitive, spatially resolved, multi-elemental and versatile analytical instruments were needed. The techniques employed should be as a noninvasive as possible and able to give complementary information from macroscopic to nanometer scales. In this work, X-ray based spectroscopy including energy dispersive X-ray fluorescence spectroscopy (EDS), Proton-induced X-ray emission spectroscopy (PIXE), and micro-beam X-ray fluorescence spectroscopy (µ-XRF) were used to analyze chemical composition of the Lanna-style glass. Microstructure was also studied. It can be concluded that these techniques in combination are powerful for the investigation of heterogeneous glassy materials.

Eco-Glass Based on Thailand Quartz Sands and Bismuth Oxide

Ecological glass with non-toxic was fabricated in bismuth-bearing glass using mainly local quartz sands and various concentration of bismuth oxide. The specific gravity (SG), refractive index (RI), thermal expansion coefficient (CoE) and hardness (HV) were determined. It was found that the values of SG, RI and HV were increased linearly as the increasing of bismuth oxide, whiles that of CoE was decreased. This glass is environmentally friendly materials.

FWHM Calculation of Zircon Gem-Materials before and after Thermal Enhancement

Zircon samples from Ubon Ratchathani, Thailand; Rattanakiri, Cambodia and Dak Nong, Vietnam change their color from light brown and reddish-brown to blue color after thermal enhancement at 1000 ๐C in reducing condition for 60 min. The high temperature is one of the factors for the zircon structure to recrystallize. The objective of this study is to describe the crystal structure of zircon samples before and after thermal enhancement. Zircon is a metamict mineral whose structure is destroyed by some trace elements. There are radioactive elements such as U and Th in the zircon structure. In this study, Raman spectroscopy was used to analyze the molecular vibration in zircon structure before and after thermal enhancement. As a result, the Raman spectra of zircon samples after thermal enhancement show the Raman shift at peak position of V3(SiO4) stretching around 1008cm-1to higher wavenumber concerning to the full width at half maximum (FWHM) values calculated by PyMCA software. The results could be summarized that the metamict zircon will be recrystallized to the crystalline zircon after thermal enhancement. The advantage of this study is about the identification of zircon before and after thermal enhancement.

Ancient Glass Bead from U-Thong Ancient City Site, Central Thailand

The goal of this research is to build a database for the ancient glass beads from U-Thong excavation site (Dvaravati Period, 6th to 13th centuries). We can compare the chemical properties among the ancient glass beads from different sites in order to learn about the ancient trading route of those glass beads. The 30 samples and 12 colors (translucent to opaque and various colors) were collected from U-Thong archaeological site, Suphanburi Province, Central Thailand. The ancient glass bead samples were studied about the physical and chemical characteristics as well as the surface features. The glass beads were analyzed by the scanning electron microscope coupled with energy dispersive x-ray spectrometer (SEM-EDS), Fourier transform infrared spectrometer (FTIR) and Atomic Force Microscope (AFM). The chemical composition of the dark blue bead for example contained 2.25 wt% MgO, 90.98 wt% SiO2, 1.26 wt% K2O, 4.17 wt% CaO and 0.59 wt% CuO. The FTIR spectrum of ancient glass beads is rarely to interpret their molecular vibration. The AFM allowed us to see the glass corrosion in nano scale on the surface. This research can help Thai archaeologists to identify the characteristics of ancient glass bead in the Central Thailand.