Computational analysis of contamination in Kojima Lake using upwind-type finite element method

We have computed the phase of spreading contaminations in Kojima Lake by using the upwind-type finite element method. We have treated the two cases: the pollutant flows from the Sasagase river and from the Kurashiki River. We see that the upwind-type finite element method is effective in both cases, when the diffusion constant is quite small

Sr-Nd-Pb isotope systematics of fine sediments from the modern rivers in SW Japan : Implications for sediment provenance of the Northwest Pacific

As reference data for comprehensive provenance analyses of deep-sea sediments in the Northwest Pacific region, we present Sr-Nd-Pb isotopic compositions of fine sediments sampled from 48 rivers in southwest Japan. Sr-Nd-Pb isotope ratios are reliable indicators of sediment sources. Although isotopic data of fine sediments in Chinese arid regions, known to be Asian dust sources, are abundant, comparable data from southwest Japan are scarce, even though southwest Japan, owing to its tectonic activity, is a major sediment source to the Northwest Pacific. Sr-Nd-Pb isotope ratios of our riverine fine sediment samples vary greatly (87Sr/86Sr, 0.707–0.724; 143Nd/144Nd, 0.5120–0.5129; 206Pb/204Pb, 18.16–18.89; 207Pb/204Pb, 15.55–15.66; and 206Pb/204Pb, 38.13–39.09), and these variations are clearly dependent on the principal geology of each river's watershed. These results indicate that these isotope ratios can be effectively used to discriminate the geological sources of the sediments. Sediments from watersheds dominated by Quaternary volcanic rocks have the lowest 87Sr/86Sr and Pb isotope ratios and the highest 143Nd/144Nd ratios, whereas sediments from watersheds dominated by accretionary sedimentary rocks generally have high 87Sr/86Sr and Pb isotope ratios and low 143Nd/144Nd ratios, but their specific values vary depending on the age and geographic location of the rocks. The isotope compositions of sediments from watersheds with exposed Cretaceous granitic and metamorphic rocks are also distinctive. Comparison between the isotope ratios of Japanese river sediments and the Northwest Pacific seafloor sediments suggests the importance of sediment transport by the Kuroshio Current to the Northwest Pacific

Computational water analysis in an artificial lake: Kojima Lake case

We treat the problem of water pollution by the method of a mathematical model. We illustrate the method of analysis with Kojima Lake. We analyze in-flow and out-flow of the lake, compute numerical solutions of the governing equations of the water flow and the pollutant. The simulation leads to the conclusion concerning the figure of Kojima Lake

A criterion for determining whether multiple shells support a tt-design

In this paper, we provide a criterion for determining whether multiple shells support a $t$-design. We construct as a corollary an infinite series of $2$-designs using power residue codes.Comment: 16 pages. arXiv admin note: substantial text overlap with arXiv:2309.03206, arXiv:2305.03285, arXiv:2310.1428

Pseudotachylytes from Langhovde and Skarvsnes in the Lützow-Holm Complex, East Antarctica, and their conditions of formation

The Tenth Symposium on Polar Science/Ordinary sessions: [OG] Polar Geosciences, Wed. 4 Dec. / Entrance Hall (1st floor), National Institute of Polar Researc

Geological field survey in the regions of L*tzow-Holm Bay, Prince Olav Coast and Enderby Land, 2018-2019 (JARE-60)

The Tenth Symposium on Polar Science/Ordinary sessions: [OG] Polar Geosciences, Wed. 4 Dec. / 3F Seminar room, National Institute of Polar Researc

Aqueous solution properties of pyridinium-type perfluorinated surfactants and simulation of mixture CMC

The critical micelle concentrations (CMCs) of 1,1,2,2-tetrahydroperfluoroalkylpyridinium chloride have been determined by measurements of surface tension and electrical conductivity, etc. The CMCs of perfluorinated surfactants were only about 0.02 times that of hydrocarbon one with the same carbon number. Aqueous solutions of fluorocarbon surfactants gave low surface tensions in comparison with those of hydrocarbon surfactants. The area per surfactant molecule at the airâwater interface decreased with increasing length of the fluorocarbon chain. Electromotive force measurements were made with chloride-responsive electrodes on surfactants solutions. The micelle ionization degrees decreased with increasing length of the alkyl chain. The group contribution method simulated the mixture CMCs of binary surfactants with various alkyl chain lengths. The group contribution method proved to be very useful to predict not only the mixture CMCs but also the demixing regions of binary mixtures having great differences in CMC