نتایج جستجو برای: obsidian
تعداد نتایج: 368 فیلتر نتایج به سال:
Chemical fingerprinting using major or trace element composition is used to characterize the Mediterranean island sources of obsidian and can even differentiate as many as nine flows in the Monte Arci region of Sardinia. Analysis of significant numbers of obsidian artifacts from Neolithic sites in the central Mediterranean reveals specific patterns of source exploitation and suggests particular...
A variety of obsidian from Glass Buttes, Oregon, known as “fi re” obsidian and named for thin layers showing various colors, was investigated with fi eld-emission scanning electron microscopy, X-ray energy-dispersive spectroscopy, electron back-scatter diffraction, and optical spectroscopy methods. Our study reveals that the thin layers mainly consist of concentrated nanometric crystals of magn...
[1] Explosivity of rhyolite domes depends on bubble nucleation and growth. To understand these processes, we measure millimeter-scale variations in H2O by synchrotron Fourier transform infrared (FTIR) spectromicroscopy on interlayered obsidian-pumice samples. The H2O contents of all samples are above the 1-atm solubility value ( 0.10wt.%) and decrease systematically towards vesicular zones, ind...
Sourced from the Tyrrhenian Islands and exchanged over long distances, obsidian was used widely across prehistoric Western Europe. An core bladelets a newly discovered rockshelter site in south-eastern Spain, however, raised possibility of an unrecognised mainland source obsidian. EDXRF analysis Early Magdalenian finds La Boja links them to 125km south-west. The artefacts were discarded during ...
ARTICLES Ultraviolet Spectroscopy and the Composition of Cometary Ice: P. D. Feldman....................................................... Sweden Beyond Oil: The Efficient Use of Energy: T. B. Johansson et al. ................................................. Obsidian Dating and East African Archeology: J. W. Michels, I. S. T. Tsong, C. M. Nelson...................................................
Thermodesulfobacterium geofontis OPF15(T) (ATCC BAA-2454, JCM 18567) was isolated from Obsidian Pool, Yellowstone National Park, and grows optimally at 83°C. The 1.6-Mb genome sequence was finished at the Joint Genome Institute and has been deposited for future genomic studies pertaining to microbial processes and nutrient cycles in high-temperature environments.
Graphics Processing Units (GPUs) offer potential for very high performance; they are also rapidly evolving. Obsidian is an embedded language (in Haskell) for implementing high performance kernels to be run on GPUs. We would like to have our cake and eat it too; we want to raise the level of abstraction beyond CUDA code and still give the programmer control over the details relevant to kernel pe...
The ratioβ of the radiation pressure force to the gravitational attraction is calculated for circumstellar grains. Eleven stars of various spectral type are considered and their spectral flux compiled from available data sometimes supplemented by appropriate models. The materials composing the grains are a silicate (obsidian), organic materials (ice tholin, poly-HCN), graphite and glassy carbon...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید