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水害時の高齢者施設における階上への垂直避難に関する研究－引きずり避難方法を用いた避難介助－
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）application/pdf地震や水害のリスクが高まる中、津波や台風・集中豪雨による高齢者施設入所者の死亡事例が絶えない。津波、洪水、土砂災害のリスクが高い区域に在する要配慮者利用施設は、避難確保計画の作成、避難訓練の実施が義務化されているが、約半数が作成に至っていない。本研究では水害時に階上へ避難するための方法として「引きずり避難」に着目した。既往研究においては多くの介助者数が必要な避難介助方法が利用されており、少ない介助者数と介助量で可能とされる引きずり避難の介助負担を調査しその有効性を検討することとした。その前提として、水害時に自施設内で階上に避難する事が想定可能な高齢者施設がどの程度あるのか、各施設での津波避難対策や準備状況などの実態把握が必要であると考えた。北海道沿岸部都市の中で津波発生リスクの高い太平洋沿いに位置する函館市、室蘭市、苫小牧市、釧路市の高齢者施設において、事前調査、アンケート調査を実施し、対象施設のうち4 件に実地調査を実施した。国土交通省による津波予測浸水深とそれに耐えうる建物構造の関係に関する資料を参考に、各高齢者施設の階数、構造、津波予測浸水深の関係から、津波時に自施設内で階上に避難することで入所者の命を救う事が可能なのは全体の55％程度と想定した。また垂直避難に使用する階段は主にスタッフ動線として設計されており、勾配は30～35°程度であることが多かった。次に引きずり避難方法に関する基礎データを収集するため実験を実施した。高齢者施設において自力避難が困難な入所者を2 人介助の引きずり避難方法により階上へ垂直避難させることを想定し、50kg の人型ダミーを勾配33°、幅1250mm、踏面300mm、蹴上180mm の階段に設置したアルミ板の斜面上で引き上げた時の牽引力、所要時間を測定した。結果から背筋力が大きい被験者はできるだけ少ない力と短時間で引き上げ、背筋力が小さい被験者は必要以上に大きな力を発揮し引き上げに時間を要した。さらに、踊り場（幅2650mm、奥行1310mm）を介した上記と同じ条件の階段1 層分において、2 名介助での引きずり避難方法を用い、45kg の人型ダミー（測定機器含む）3 体を繰り返し上階に引き上げた時の牽引力、所要時間を測定した。結果から、背筋力が小さいペアであっても3名の入所者を繰り返し避難介助する事が可能であること、男性介助者が1名でもいれば、避難時間は大きく短縮することがわかった。本研究の提言として、引きずり避難を効率的に行うために適した階段構成を検討した。勾配は緩やかであると効率的に引き上げが可能であるためバリアフリー新法の推奨する28°が適している。踊り場は方向転換をする際に奥行が必要となり、奥行1810mm、幅2900mmの寸法が周りやすい。階段幅は1650mmで介助者が進行方向を向き、余裕を持って避難器具を操作できるため引きずり避難に適している。効率的に引きずり避難が可能な避難器具、介助方法、階段構成について、今後さらに科学的に検討し、行政へ情報提供をし続けることにより、具体的な避難介助方法が想定できず避難確保計画や避難マニュアルの策定に苦慮する施設の一助としたい。Facilities for people with special needs in areas where there is a high risk of tsunamis, floods, and sediment-related disasters are obliged to create an evacuation security plan and conduct evacuation drills. However, about half have not created it. One of the reasons for this is the lack of information on evacuation methods. In this study, we focused on "dragging evacuation" as an assistance method for evacuating upstairs in the event of a flood. Dragging evacuation is possible with a small number of caregivers and a small amount of assistance. We decided to examine the effectiveness of dragging evacuation. We thought we needed to know how many facilities for the elderly could evacuate residents upstairs to their own facilities in the event of a tsunami. Surveys were conducted at facilities for the elderly in four cities along the Pacific coast of Hokkaido. About fifty-five percent of facilities for the elderly in the tsunami inundation area can save the lives of residents by evacuating upstairs to their own facilities. This data was based on materials related to "building structures that can withstand tsunamis" by the Ministry of Land, Infrastructure, Transport and Tourism. Next, we conducted an experiment on the amount of assistance required for dragging evacuation. The experiment was conducted on the assumption that two caregivers would evacuate the elderly who have difficulties in self-evacuation upstairs using the dragging evacuation method in facilities for the elderly. Two subjects lifted a 50 kg humanoid dummy on a slope set up on a staircase with a slope of 33 °. We measured and considered the pulling force and the required time. In addition, two subjects lifted 45 kg (measuring equipment and humanoid dummy) upstairs on the slope installed on the U-Shaped staircase which includes a landing at the switchback. The pulling force and the required time were measured. The experiment was repeated 3 times on each pair. We propose a staircase structure that enables efficient dragging evacuation. The slope of 28 ° recommended by the new barrier-free law is suitable. The landing is easy to turn around with a depth of 1810 mm and a width of 2900 mm. The width of the stairs is 1650 mm, which is suitable for dragging evacuation. We will inform local governments and facilities for the elderly that the dragging evacuation method is one of the effective assistance methods for evacuation upstairs in the event of a disaster in facilities for the elderly. I hope that the managers of facilities for the elderly will use this to help formulate specific evacuation plans.doctoral thesi
自己加圧式ロケットエンジン用液体推進剤の流動特性に関する研究
Get PDF室蘭工業大学Muroran Institute of Technology博士（工学）application/pdf航空宇宙産業の発展に伴い，推進系の小型，軽量，簡素化が求められている．これらの需要に応える選択肢の一つに，亜酸化窒素の推進剤利用が挙げられる．亜酸化窒素は，常温で高い飽和蒸気圧を有することから，別途加圧システムを必要せず自己加圧供給が可能であるほか，常温で液体として取り扱うことができる．これらの特長により，打ち上げ用ロケットだけでなく，小型衛星のキックモータや姿勢制御用スラスタ，惑星着陸および帰還用ロケットへの適用も期待されている．一方で，自己加圧供給特有の課題も存在する．推進剤を自己加圧供給する場合，圧力低下による減圧沸騰やキャビテーションにより流れが混相化するため，圧力損失および流量予測が困難な点である．推進剤の流量はロケットエンジンの推進性能に直結するため，推進系の適切な設計や推力予測精度の向上には，推進剤流量の推定は極めて重要な要素である．本研究では，亜酸化窒素を用いた各種試験を実施し，実験的に得られた結果を多角的に評価することで，自己加圧式ロケットエンジンに伴う気液二相流の流動特性を解明することを目的としている．また，得られた知見から流量および推力の予測精度向上を図るものである．ここで対象とする流れ場は非定常性の強い気液二相流であり，温度や圧力のみで評価することは困難である．そこで，可視化した流路内を通過する気液二相流を高速撮影することで流動様式を評価し，壁面の気泡流速は 5-10 m/s 程度，気泡径は数 100 μm であることを明らかにした．また，新規に開発したボイド率計により気相と液相の割合を計測し，流動特性との相関を評価した結果から，ボイド率は 0.3-0.6 程度であり，供給に伴い次第に増加する傾向が明らかになった．また，ボイド率の増加に伴いインジェクタ流量係数は線形的に低下する傾向が示唆された．さらに，二相流 Re 数で摩擦損失係数を評価すると，単相流における同 Re 数における理論値に対して，最大で 2 倍程度になることを明らかにした．一方で，インジェクタ流量係数について，流体温度の上昇とともに流量係数も増加傾向にあることが明らかになった．亜酸化窒素の熱力学的効果パラメータは極めて高く，流体温度が高いほど，生成される気泡の体積抑制作用である熱力学的効果が顕著になったためと考えられる．また，インジェクタ下流圧が上流圧の半分程度以下である場合，インジェクタポート内で臨界二相流を形成することで流れがチョークするのに対し，比較的燃焼圧が高い（インジェクタレジスタンスが小さい）条件では供給系と燃焼の連成による燃焼振動が見られ，流量係数は流し試験にて取得した値よりも大きく見積もられる可能性が示唆された．With the development and progress within the aerospace industry, propulsion systems are required to be compact, lightweight, and simple. One solution to respond to these demands is using nitrous oxide as liquid propellant. Since nitrous oxide has a high saturated vapor pressure, it can be self-pressurized without an external pressurizing system and can also be handled as a liquid at normal temperature. Due to these advantages, it is expected to be used not only to launch rockets, but also to kick motors for small satellites, attitude control thrusters, planet landing, and return rockets. On the other hand, there are some problems specific to self- pressurization. With self-pressurization, it is difficult to predict the pressure loss and flow rate of the propellant because the gas-liquid two-phase flow is formed by flashing and cavitation caused by the pressure drop. Estimating the propellant mass flow rate is extremely important to accurately predict the thrust profile. In this study, the flow characteristics of gas-liquid two-phase with self-pressurization were evaluated by conducting various tests using nitrous oxide. The findings obtained in this study may contribute to improving the prediction accuracy of flow rate and thrust. The flow focused on in this study is a strongly unsteady gas-liquid two-phase flow, and it is not appropriate to evaluate the flow regime only by temperature and pressure. Therefore, the flow regime was evaluated by high- speed shooting of the gas-liquid two-phase flow passing through the visualized feed line. This method showed that the bubble flow velocity on the wall surface was about 5-10 m/s and the bubble diameter was several hundred μm. In addition, the results of measuring the ratio of gas and liquid phase with a newly developed void fraction meter suggest that the void fraction was about 0.3-0.6, and it gradually increased with supply. It was also found that the injector flow coefficient tended to decrease linearly as the void fraction increases. Furthermore, when the friction factor was evaluated by the two-phase flow Re number estimated from the obtained void ratio, it was about twice the theoretical value of the same Re number in the single-phase flow. On the other hand, it became clear that the injector flow coefficient tends to increase as the fluid temperature rises. The thermodynamic effect, which is the volume-suppressing effect of the bubbles generated, became remarkable as the fluid temperature increased. When the downstream pressure of the injector was less than half of the upstream pressure, the two-phase flow was choked at the injector port. The chamber pressure oscillation was observed due to the coupling of the supply system and combustion, suggesting that the injector flow coefficient may be larger than the value obtained in the cold flow tests.doctoral thesi
Analysis of sweating efficiency and its effects on the heat strain alleviation of clothed subjects
Get PDFapplication/pdfSweating efficiency (SE) is essential for evaluating heat strain. The dripping of sweat off the skin surface of a nude subject occurs locally at an area where the secreted sweat exceeds the local evaporative capacity. However, in clothed subjects, “dripping” sweat is absorbed by clothing. In the present paper, the cooling efficiency of the sweating of a clothed subject is analyzed in relation to SE. First, typical patterns for the regional distribution of the sweat rate (SR) and the capacity of evaporation (CE) of a nude subject were introduced, and the dripping sweat rate was derived as a surplus of the SR over the CE; an equation of SE was derived from combinations of the two typical SR patterns and the uniform CE pattern. Then, the values of SE were calculated numerically, and the results were found to be approximately equal to those obtained experimentally by Alber–Wallerström & Holmér and theoretically from the equation of 1 − 0.5wsw2 used in ISO7933. Based on these results, the SE was improved by arranging the distribution of the CE by controlling air velocities over the body surface. Further, the improved SE was found to contribute to the heat strain alleviation of clothed subjects.journal articl
Numerical Simulation of the Daikai Station Subway Structure Collapse due to Sudden Uplift during Earthquake
Get PDFapplication/pdfThe Daikai Station subway structure in Japan completely collapsed during the Hyogoken-Nanbu earthquake that occurred on January 17, 1995. Based on the numerical results obtained by two-dimensional finite-element analysis, the structure is believed to have collapsed as a result of strong lateral vibration. However, because it deformed in an approximately symmetrical manner with respect to the shortened central columns, it might have experienced catastrophic collapse due to vertical impulse motion. To investigate the dynamic response behavior of the structure due to sudden upward loading, a three-dimensional elastoplastic transient response analysis was conducted considering an isolated upward pulselike displacement wave from the bedrock. The results of this study suggest that the central column of the structure reached axial compression failure due to the amplitude of the displacement wave increasing significantly at the lower end of the column. This method can numerically reproduce the collapsed state of the structure and the considerable settlement of the ground surface due to the occurrence of the high-intensity earthquake.journal articl
Characterization of cellophane birefringence due to uniaxial strain by focused surface plasmon microscopy
Get PDFapplication/pdfIn this paper, we study the relationship of local birefringence and stress oriented inhomogeneous elasticity of a sample from the spatial frequency response of focused surface plasmon (FSP). The birefringence of the sample varies the propagation constant of surface plasmon with regard to its direction and produces an elliptic absorption pattern in the reflected spatial frequency distribution. Birefringence is calculated from the ratio of the propagation constant along the fast to slow axis of the sample. The change in eccentricity was proportional to the applied stress on cellophane film. A strong correlation (0.94∼0.97) exists between FSP and phase shifting interferometry results.journal articl
Charge density waves in cuprate superconductors beyond the critical doping
Get PDFapplication/pdfThe unconventional normal-state properties of the cuprates are often discussed in terms of emergent electronic order that onsets below a putative critical doping of x(c)approximate to 0.19. Charge density wave (CDW) correlations represent one such order; however, experimental evidence for such order generally spans a limited range of doping that falls short of the critical value x(c), leading to questions regarding its essential relevance. Here, we use X-ray diffraction to demonstrate that CDW correlations in La2-xSrxCuO4 persist up to a doping of at least x=0.21. The correlations show strong changes through the superconducting transition, but no obvious discontinuity through x(c)approximate to 0.19, despite changes in Fermi surface topology and electronic transport at this doping. These results demonstrate the interaction between CDWs and superconductivity even in overdoped cuprates and prompt a reconsideration of the role of CDW correlations in the high-temperature cuprate phase diagram.journal articl
A study on shelter airport selection during large-scale volcanic disasters using CARATS open dataset
Get PDFapplication/pdfAir transport supports economic growth and prosperity through the movement of passengers and goods. As it grows more extensive and more complex, the more vulnerable its operations to unexpected natural disasters (e.g., typhoon and volcanic eruption) will become. In Japan, many active volcanos are affecting its airspace and considered a threat to the national air transportation and critical aviation equipment such as aircraft. The study focuses on solving the evacuation of the affected aircraft during the volcanic eruption by proposed the shelter airport selection model using the historical data of volcanic eruption, aircraft movement, and airports data in Japan. The model was applied to the genetic algorithm (GA), the metaheuristic algorithm to provide the approximate solution of the suitable shelter airport with minimum flight time and no exceeded shelter airports' capacities for the aircraft evacuation.journal articl
Statistical Modelling of Machining Error for Model-Based Elastomer End-Milling
Get PDFapplication/pdfElastomer end-milling has attracted attention for use in the small-lot production of elastomeric fragments because the technique is an applicable method for a large variety of materials and does not require the preparation of expensive and time-consuming moulds. In order to effectively utilize elastomer end-milling, it is necessary to ensure the machining accuracy of elastomeric parts machined through this technique. However, the control method of machining error in the elastomer end-milling has not been presented since most machining services of the elastomeric part are based on enterprise-dependent dexterities or know-how. The objective of this paper is to construct and utilize a machining error model for elastomer end-milling. A statistical model based upon physical states and machining conditions is introduced and investigated. In this paper, a framework for modelling the machining error in elastomer end-milling is also proposed. In the framework, the candidates of model variables are evaluated based on the preliminary experiments. Moreover, a statistical model is constructed by using the selected variables. Candidate variables are cutting conditions and predictable physical state variables such as workpiece deformation and cutting force. The framework is investigated by evaluating error prediction with the experimental results. An identified error model from limited machining cases can estimate the machining error of different machining cases. The results indicate that the proposed modelling method is capable of supporting to achieve model-based precision elastomer end-milling.journal articl
International Academic Exchange Between Chiang Mai University and Muroran Institute of Technology(On Activities Through Joint Symposia)
Get PDFapplication/pdfWe concluded the international academic exchange agreement with the Chiang Mai University (CMU) in Thailand at 2005. The CMU and the Muroran Institute of Technology (Muroran-IT) have been maintaining student and academic exchange, research collaboration, and some activities. Since 2010, the Department of Industrial Engineering at CMU and the Department/Course of Mechanical Systems Engineering at Muroran-IT have been doing systematically collaboration particularly in terms of education and research based on the student-centered activities. A representative activity is a joint symposium entitled MIER (Mechanical Engineering, Industrial Engineering, and Robotics), which has been alternatively held in Thailand and Japan every one or two years. Each symposium consisted of academic and cultural events including lectures, presentations, discussion, information and idea exchange, factory and laboratory visits, hands-on classes, excursion, meetings, and homestay. In this report, looking back a decade, we summarize the history and activities of the symposia briefly.特集departmental bulletin pape
Report on International Symposium on Materiome Research 2019 and the Comparison of Research System in the University between Taiwan and Japan
Get PDFapplication/pdfThe summary of International Symposium on Materiome Research 2019, which was held on August 22, 2019, is reported. In the symposium, there were 14 invited talks from National Chiao Tung University in Taiwan, and Muroran Institute of Technology in Japan. The difference in the research system in the university between Taiwan and Japan is discussed.特集departmental bulletin pape