Dynamic Finite Element Analysis of Impulsive Stress Waves Propagating from Distal End of Femur

The human femur is subjected to an impulsive load at its distal end during daily life. Femoral bone fracture caused by impact loading is common in elderly women. It is important to clarify the dynamic response of the femur and to evaluate the change in its stress state during impact loading. A 3-dimensional model of the femur was prepared in the present study, and the impulsive stress waves propagating from the distal end of the femur were analyzed by the dynamic finite element method. This model showed that the von Mises equivalent stress is large on the anterior and posterior sides of the mid-diaphysis when the impact direction is different from that of the bone axis. As for the femoral neck, the absolute value of minimum principal stress initially increases on the medial side;slightly later the maximum principal stress increases on the lateral side. In this case, the absolute value of the maximum principal stress was found to be larger than that of the minimum principal stress, and the absolute value of the principal stress decreased as the impact angle increased. Further, the femoral neck and the trochanter were shown to have a higher risk of bone fracture when the impact direction is coincident with the bone axis

Ice Core Records of Antarctic Warming Events in the Last Glacial Period

第3回極域科学シンポジウム　横断セッション「海・陸・氷床から探る後期新生代の南極寒冷圏環境変動」11月26日（月） 国立国語研究所 ２階講

乗鞍岳における融雪期の積雪中の化学物質の動態

A snow pit study was conducted on Mt. Norikura in the Northern Japan Alps from January to April to clarify the chemical dynamics in the snowpack during the snowmelt season. Little snowmelt occurred before February , the first snowmelt occurred between February and , and the peak of the snowmelt season occurred after March . Snow layers with remarkably high Cl , NO , and SO concentrations in the snowpack were traced; furthermore, the snow layers with high SO concentrations were found to disappear first. It was concluded that the ease with which the ions were flushed out from the snowpack was SO NO Cl.ArticleBulletin of Glaciological Research. 26:9-14 (2008)journal articl

北アルプスの山地流域における水収支と物質収支

We have investigated the water balance and mass balance for four years in Maekawa River basin on the eastern slope of Mt. Norikura-dake. In this region, the precipitation frequency is high from the rainy season to the autumn. The maximum base-flow discharge occurs in the spring snowmelt season. The pH and electric conductivity of the river water decline rapidly with the beginning of the snowmelt runo and temporarily decrease when the discharge increases temporarily in the rainy season or during a typhoon event. The Cl concentration of the river water increases in the early stage of snowmelt season since there is a considerable amount of sea salt in the snow. In addition, the NO concentration of the river water increases when the rainfall increases the discharge. The major ion concentration of the river water, except Cl and NO almost synchronizes with the change in the electric conductivity. In the mass balance of cations, the runo rate from the river basin considerably exceeds the atmospheric deposition rate to the river basin. This is because there is extremely much elution of ions from new volcanic rocks and soils. Further, the atmospheric deposition rate of NO is larger bigger with the biological consumption in the river basin than the runo rate from the basin.ArticleBulletin of Glaciological Research. 26:1-8 (2008)journal articl

中部山岳地域における降雪条件の違いによる積雪中の化学特性

We conducted a snow survey in February 2006 and January 2007 in Japan Alps. Approximately 0.60m and 1.05m snowfalls were deposited at the study site in February 2006 and January 2007, respectively. It was observed that the occurrence of snowfall was due to the low pressure formation in the vicinity of Japan and it also being the winter monsoon period. As a result of the analyzed snowpack, including new snow at a high resolution every 0.03m, a plurality of high-electric conductivity layers were observed at di erent depths. From the measurement of the major ion concentrations, it was observed that the high-electric conductivity layers had di erent chemical characteristics. High concentrations of NO3 and SO42 deposits were observed in the snowpack layer that was formed due to the low-pressure system that passed in the vicinity of Japan. On the other hand, the layer that formed during the winter monsoon pattern, large amounts of sea salts were deposited in the snowpack in January 2007. However, layers with a high sea-salt concentration were not observed in February 2006. We analyzed the movement of the air mass that flowed into the study area. Air mass passed through the city at the time of the passage of the low-pressure system. In addition, the air mass that crossed the Sea of Japan entered the study area during the winter monsoon pattern. However, the movement of the air mass was di erent during the winter monsoon pattern in February 2006 and January 2007.ArticleBulletin of Glaciological Research. 26:15-21 (2008)journal articl

Chemical characteristics of snowpack on the Dome Fuji route, Antarctica

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月15日（火） 統計数理研究所 3階リフレッシュフロ

Reduced marine biogenic sulphate flux in East Antarctica during glacial periods - Based on ion chemistry records from Dome Fuji ice core -

The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / 2F Auditorium, National Institute of Polar Researc

Seasonal variation of bacteria from surface snow pit at NEEM, Greenland

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月29日（木） 国立国語研究所 ２階ロビ

極域雪氷試料におけるダスト濃度分析法の改良と試料保存過程によるダスト濃度への影響

極域雪氷試料を対象として，ダスト分析過程および分析管理の改良と，保存過程によるダスト濃度への影響の評価を行った．ダスト分析過程と分析管理の改良では，校正曲線変更に伴う粒径区分とパルス電圧閾値の変更，繰り返しの分析精度とワイパーのブランク濃度の確認，標準粒子測定によるセンサー感度変動管理を行った．ダスト分析用試料の保存容器の検討の結果，パッキンなしの15mlガラス瓶で，ダスト濃度への影響が最も低かった．ドームふじ氷床コア試料による冷蔵，凍結保存過程の検討の結果，冷蔵保存によるダスト濃度への影響は，1年間で，分析精度以内の4%以下の減少に留まった．凍結保存ではその前後でダスト濃度の増加傾向が見られ，粗大粒子の割合は減少した．これらは，凍結・融解の際のダスト粒子の変化や試料保存容器の材質などの影響が考えられる．またダスト濃度への分散剤添加の影響は，冷蔵，凍結保存に対して，明らかに保存状態を向上させているとはいえなかった．We sought to improve the analytical methods employed when operating a laser particle counter and to evaluate the influence of the storage processes on dust concentrations in polar snow and ice samples.　We corrected the particle size ranges and threshold voltage using the new calibration curve, confirmed the analytical precision and dust concentrations of blank of wipers using in a clean room, and managed any variations in the laser sensor\u27s sensitivity by measuring standard particles.　The 15 ml glass screw bottles without packing (liner of cap of bottles) yielded the lowest dust concentration of the blank among two types of bottles and nine types of packing for dust analysis.　Storage of samples of the Dome Fuji ice core (Antarctica) in a refrigerator for 1 year resulted in just a 4% decrease in dust concentration, which is within the analytical precision of the laser particle counter.　Storage in a freezer resulted in an increase in dust concentrations and a decrease in the ratio of large particles more than 0.98 μm in particle diameter in the samples, suggesting a change in dust particle size during storage and an influence by the materials of the storage bottles.　The addition of dispersants to the Antarctic snow samples is not clearly suitable when analyzing dust concentrations after sample storage by refrigeration or freezing