[1] To investigate how canopy thickness and canopy saturation affect the amount and kinetic energy of throughfall, we conducted indoor experiments using a 9.8-m-tall transplanted Japanese cypress (Chamaecyparis obtusa) and a large-scale rainfall simulator with spray nozzles at a height of 16 m. The amount of throughfall and raindrop sizes and velocities were measured at twenty-four points under four canopy structures generated by staged branch pruning. Decreasing the canopy thickness resulted in increases of the initial throughfall amount, volume proportion of large throughfall drops, the number of drops with high velocities, and throughfall kinetic energy. Compared to a saturated canopy, a canopy undergoing wetting had lower throughfall amounts and volume proportion of large drops, but higher mean drop velocity. Canopy thickness affected throughfall generation by affecting the processes of canopy saturation and drop generation within the canopy. Citation: Nanko, K., Y. Onda, A. Ito, and H. Moriwaki (2008), Effect of canopy thickness and canopy saturation on the amount and kinetic energy of throughfall: An experimental approach, Geophys. Res. Lett., 35, L05401,

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We report a facile synthetic protocol from aqueous solution for Na3SbS4-Na2WS4 superionic conductors with sodium-ion conductivity of 4.28 mS cm−1 at 25 °C, which is the highest one in reported sulfide electrolytes prepared via liquid-phase methods.

Novel chiral and enantiomerically pure phospholes, which have axially chiral biaryl substituents at the 2- and 5-positions of the phosphole rings, have been prepared and converted into a variety of phosphametallocenes with retention of the chiral substituents. The phospholes and the phosphametallocenes have been applied to palladium-catalyzed asymmetric hydrosilylation of 5,5-dimethyl-1-hexen-3-yne to give an axially chiral allenylsilane with high enantioselectivity of up to 92% ee.

Indonesia is one of the largest Ni ore producers in the world and is also expected to be an important potential source of some critical metals (e.g., Co, Sc, rare-earth elements, and platinum-group elements). However, few studies have examined Ni laterite deposits in this country. In this study, we investigate Ni enrichment and the potential accumulation of critical metals in four laterite profiles with varying degrees of serpentinization and weathering intensity in the Soroako and Pomalaa mining areas of Sulawesi, Indonesia. We integrate geochemical evaluation with a mass-balance approach and mineralogical analysis to better constrain the geochemical factors influencing the mobilization of Ni during lateritization. Nickel contents in the saprolite horizon of the profiles that are strongly weathered and developed over serpentinized peridotite are higher than those that are weakly weathered and developed over unserpentinized harzburgite. The bulk Ni contents of saprolite horizons are related to Ni contents of Ni-bearing Mg-phyllosilicates, which suggests that Ni remobilization is the main control on Ni enrichment in the profiles. Massbalance calculations reveal that the amounts of gained Fe and Ni in the profiles are positively correlated. This relationship indicates that the redistribution of Ni is likely controlled by the aging of Ni-bearing goethite (dissolution/ recrystallization) involving ligand-promoted dissolution by organic matter and/or reductive dissolution by microbial activity near the surface. Critical metals show enrichment in specific horizons. Enrichments in Co and rareearth elements are strongly influenced by the formation of Mn-oxyhydroxides in the oxide zone of the profiles. In contrast, Sc, Pt, and Pd show residual enrichment patterns, with grades influenced mainly by their initial contents in bedrock. The profiles show a positive correlation between Sc and Fe, as reported for other Ni laterite deposits. Among the critical metals, Sc, Pt, and Pd contents in the studied profiles are comparable with values reported from other Ni laterite deposits worldwide.

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Myanmar has a drier sub-tropical climate than countries that typically contain Ni laterite deposits, but hosts a Ni laterite deposit at Tagaung Taung. Given that Ni enrichment processes in the Tagaung Taung deposit are poorly understood, we investigated the geochemical and mineralogical evolution of two weathering profiles developed on different bedrocks in the central part of Myanmar: a partly serpentinized harzburgite at Tagaung and an almost completely serpentinized peridotite at Budaung. The whole-rock geochemical data indicate that Si was retained relative to Fe and Al in the weathering profiles. Nickel has been enriched to contents as high as 4.89 wt.% NiO in the saprolite layers at Tagaung, whereas the saprolite layers at Budaung contain ≤1.55 wt.% NiO. Smectite is the main mineral that formed in the saprolite layers at Tagaung, whereas secondary serpentine dominates the saprolite layers at Budaung. Microscopic observations indicate that Ni-smectite (>10 wt.% NiO), which is only observed at Tagaung, formed as a replacement product of orthopyroxene. In addition to the high Ni fixation capacity of smectite relative to secondary serpentine, Ni-rich pore water derived from the dissolution of olivine likely contributed to the high Ni contents of smectite. Our results imply that high-grade Ni laterite deposits may develop on unaltered or partly serpentinized harzburgite under the climatic conditions typical of Myanmar.

Abstract:To estimate the variability of surface runoff generation and the infiltration rate on a bare surface in a forested area, indoor experiments were conducted using 13 runoff boxes and a single transplanted Japanese cypress tree (9Ð8 m in height) in a large-scale rainfall simulator with spray nozzles (at a height of 16 m). The surface runoff was measured for applied rainfall and for 12 kinds of throughfall with different intensities and kinetic energy (KE) (found among measuring points and canopy structures). While no surface runoff was observed for the applied rainfall, surface runoff was observed for throughfall in each runoff box. Compared with the applied rainfall, the throughfall had larger drops due to canopy drip generation and thus had higher kinetic energy, which decreased the infiltration capacity. The maximum stable infiltration rate (IR MAX ) was lowest for throughfall (44Ð2 mm h 1 ). Surface runoff generation and infiltration rates varied greatly under the canopy, even though the rainfall applications were identical and the runoff boxes had identical initial soil properties. The variability of IR MAX , ranging from 44Ð2 to 120Ð2 mm h 1 , was caused by the variability of the throughfall intensity and kinetic energy. The index showing the best correlation to IR MAX was the effective unit kinetic energy (KE 0 mm : J m 2 mm 1 ). The prediction of surface runoff generation in a forested area requires estimations of the spatial variations of the amount and kinetic energy of throughfall.