109 research outputs found

    Scaled dynamic loading tests on seismic isolation bearing excluding the contamination of friction and inertia forces

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    Conventional seismic isolation-bearing testing facilities require moving horizontal platens under high compression. However, these dynamic moving platens inevitably lead to the friction and inertial forces generated by large vertical loads and inertial forces due to the dynamic mass action of the moving platen, which eventually affects the accuracy of the measured force. To solve this problem, the authors have proposed a direct reaction force measurement system (horizontal-vertical separated type) that can exclude the contamination of friction and inertial forces. Measuring pure reaction forces without the contamination of friction forces and inertia is crucial for the reliability of test results. In this paper, prior to the construction of large-scale facility, reduced-size–mockup dynamic tests were conducted using the proposed measurement concept, and its validity and accuracy were discussed. Furthermore, this system was applied to hybrid simulation tests, and the significant improvement of the proposed measurement system was observed

    The diagnostic ability of SPECT/CT fusion imaging for gastrointestinal bleeding : a retrospective study

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    Background Blood loss from the gastrointestinal tract can be an acute and life-threatening event. For the treatment of gastrointestinal bleeding, it is important to accurately detect gastrointestinal bleeding and to localize the sites of bleeding. The purpose of this study was to retrospectively assess the capabilities of SPECT/CT in the diagnosis of gastrointestinal bleeding by a comparison with planar imaging alone as well as planar and SPECT. Methods We conducted a retrospective analysis of 20 patients (21 examinations) who underwent gastrointestinal bleeding scintigraphy in the past 7 years and in whom the bleeding site was identified by endoscopy or capsule endoscopy, or in whom no evidence of gastrointestinal bleeding was identified during the clinical course. Five patients (5 examinations) were diagnosed by planar imaging (planar group). Eight patients (9 examinations) were diagnosed by planar imaging and SPECT (planar + SPECT group). Seven patients (7 examinations) were diagnosed by planar imaging and SPECT/CT (planar + SPECT/CT group). We calculated the diagnostic ability of each method in detecting the presence of bleeding, as well as the ability of each method to identify the sites of bleeding. The sensitivity, specificity, and accuracy of the methods were compared. Results The diagnostic ability of the three imaging methods in detecting the presence of gastrointestinal bleeding was as follows. Planar imaging showed 100% sensitivity (3/3), 100% specificity (2/2), and 100% accuracy (5/5). Planar + SPECT imaging showed 85.7% sensitivity (6/7), 100% specificity (2/2), and 88.9% accuracy (8/9). Planar + SPECT/CT imaging showed 100% sensitivity (6/6), 100% specificity (1/1), and 100% accuracy (7/7). The diagnostic ability of the three modalities in detecting the site of bleeding was as follows: planar, 33.3% (1/3); planar + SPECT, 71.4% (5/7); and planar + SPECT/CT, 100% (6/6). Conclusions All 3 imaging methods showed good accuracy in detecting the presence of gastrointestinal bleeding. The addition of SPECT or SPECT/CT made the anatomical position of the uptake clear and contributed to the localization of the site of gastrointestinal bleeding. Planar + SPECT/CT imaging therefore showed the highest diagnostic ability for detecting the site of gastrointestinal bleeding

    北海道礼文華峠におけるブナ分布北限域孤立個体群の立地と植生

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    筆者らはブナの分布北限域における最前線孤立個体群を太平洋から水平距離で2.5km内陸に位置する豊浦町礼文華峠の岩峰上及びその周辺で発見した.これはブナの天然分布個体群の中でも太平洋側における最北限の個体群であると考えられた。付近のアメダスのデータによれば,年平均気温7.3 ℃,年降水量1,198 mm,最大積雪深85cmであった.現地の暖かさの指数WIは52.5℃・月と推定された.ブナの分布,植生と立地の状況を明らかにするために現地調査を行った結果,以下の知見を得た.(1)岩峰上に生育する胸高以上のブナは約1.7 haの範囲(標高196 ~ 275 m)に39本生育し,胸高直径階分布は緩やかなL字型を示し,10 cm以下の個体が最多であった.(2) 岩峰のブナは主にミズナラ,ホオノキ,シラカンバと混生し,競合する針葉樹は記録されなかった.(3) 植物群落の種構成は日本海側に成立するブナ林に類似していた.(4) 土壌pHはやや酸性で5.4 ~ 5.5であり,無機態窒素は全国のブナ林の値と大きな違いはなかった.以上の知見から,礼文華峠の岩峰上のブナ個体群は,その生育に適した気候条件に加え,本州の岩峰などでしばしば優占する針葉樹類が不在であるなどの条件が重なって成立したと考えられた

    一般化応答スペクトル解析法に基づく制振ブレース構造の最適設計手法

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