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In this study, we analyze the mechanism of the future change of a occurrence frequency of Guerrilla-heavy rainfall in the Kinki region in August by focusing on the future change of lapse rate and water vapor inflow using a 5km-mesh regional climate model (RCM05). From the analysis, we show the frequency of days will increase when Showalter Stability Index (SSI), which expresses atmospheric stability, becomes lower in the Kinki region in late August although lapse rate will decrease. Lower SSI means that atmosphere is unstable. Then we show that the reason of destabilization of SSI is the increase of water vapor in lower layer. Finally, we use Self-Organizing Map (SOM), which is one cluster classification method, to reveal the main reason of the increase of water vapor in the lower layer in late August. The results show the wind field which blows from the Pacific to the Kinki region is increasing, and this explains rich water vapor flux is supplied to the Kinki region.

博士（工学） ; 日本大学

This research aims to clarify the characteristics and issues of the existence bases and sustainability of small-scale urban centers, especially those associated with mineral resource development, among urban development in arid regions related to desertification, which is one of the serious global environmental problems, Arizona, United States as an example. Arizona is one of the driest states in the United States, with vast stretches of desolate land. From the end of the 19th century to the beginning of the 20th century, many workers settled here for the purpose of developing various mining resources, and many settlements were formed. Many of them were abandoned after resource depletion, or vulnerable to disasters such as large fires caused by drying, resulting in a rapid population decline or uninhabited ghost towns. Arizona's ghost towns are: (1) Due to the low reserves of resources, resources were exhausted in a short period of time and only ruins remained; (2) Old buildings and townscapes are preserved after becoming a ghost because the town survived for a certain period of time, such as the Tombstone Historic District; (3) Like the Jerome Historic District and Bisbee, the population in its peak was about 10,000 or more, and even after the mines were closed and ghosted, the residents remained. It turned out that there are three types of settlements that have regenerated and survived through efforts. Abandoned ghost towns and huge open-pit mining sites are difficult to restore vegetation and land use, and can be a factor in desertification. It is necessary to keep a close watch so that such developments are not repeated in developing countries in the 21st century.

2017年11月に中国地方の主要河川において，バイオマス利用を目的とする植物の育種素材としてオギ（Miscanthus sacchariflorus）遺伝資源の探索収集を行った．広島，岡山，鳥取，島根，山口の各県において，合計20点を収集し，いずれも河川敷や川沿いにおいて自生集団が認められた． ; To obtain breeding materials for biomass production, genetic resources of Miscanthus sacchariflorus were searched and collected along the main rivers in the Chugoku Region of Japan in November 2017. A total of 20 clones were collected in Hiroshima, Okayama, Tottori, Shimane and Yamaguchi, where natural M. sacchariflorus populations were found at riversides and riverbeds.

Potted plants of the blackcurrant cultivar `Radiant' were subjected to soil drying with limited irrigation. The treatment decreased fruit size, increased titratable acidity, and tended to increase vitamin C content in fruits, as compared with sufficiently irrigated plants. There was no difference in soluble solid content and antioxidant capacity (evaluated using the hydrophilic-oxygen radical absorbance capacity (H-ORAC) method) between the treated and control plants. Potted plants of the blackcurrant cultivar `Nevis' were subjected to mulching culture by using a light-reflecting sheet. In this experiment, both treated and control plants were sufficiently watered. The soluble solid content and titratable acidity of the treated fruits were similar to those of the control fruits, while vitamin C content of the treated fruits was higher and antioxidant capacity of the treated fruits tended to increase as compared with the control fruits. These results indicate that soil drying and a light-reflecting sheet are capable of increasing the nutritional quality and functional components of blackcurrant fruits. ポット植えしたカシス`ラジアント'を,かん水量を制限した乾燥土壌で栽培した。その結果,十分にかん水した場合と比較して果実が小型化し,滴定酸度は上昇し,ビタミンC含量は増加傾向を示した。屈折計示度および抗酸化能(H-ORAC)は変化しなかった。また,カシス`ネービス'を,株の周辺に光反射シートを敷設して栽培した。この際,かん水は十分量を与えた。その結果,無処理の場合と比較して屈折計示度および滴定酸度は変化しなかったが,ビタミンC含量が増加し,抗酸化能は上昇傾向を示した。以上のことから,土壌乾燥処理や光反射シートの利用によってカシス果実の栄養および機能性を向上させ得ることが示された。

This study investigated future changes of a certain atmospheric characteristic, which can cause localized heavy rainfall events during Baiu season along the Japan islands. In this study, we have utilized Self-organizing map (SOM) to classify atmospheric conditions automatically and to distinguish the specific condition objectively. We have analyzed frequency of the specific atmospheric condition under the future climate as well as the present climate, and evaluated the statistical significance of frequency changes under the future climate based on ensemble experiments output with 60km resolution GCM(MRI-AGCM3.2H). By counting the number of times for the specific atmospheric condition, it is able to estimate possible changes of localized heavy rainfall pattern in the future. Our approach shows one of example that even small scale of localized heavy rainfall can be captured by considering characterized atmospheric conditions in large scale. ; This study investigated future changes of a certain atmospheric characteristic, which can cause localized heavy rainfall events during Baiu season along the Japan islands. In this study, we have utilized Self-organizing map (SOM) to classify atmospheric conditions automatically and to distinguish the specific condition objectively. We have analyzed frequency of the specific atmospheric condition under the future climate as well as the present climate, and evaluated the statistical significance of frequency changes under the future climate based on ensemble experiments output with 60km resolution GCM(MRI-AGCM3.2H). By counting the number of times for the specific atmospheric condition, it is able to estimate possible changes of localized heavy rainfall pattern in the future. Our approach shows one of example that even small scale of localized heavy rainfall can be captured by considering characterized atmospheric conditions in large scale.

Nowadays, biomass fuels become a subject which is extensively concerned from the view points of the aggravation of the greenhouse effect, acid rain, other environmental problems and the depletion of oil resources. From the point of this view, this experiment has been carried out to examine the influence of combustion characteristics and exhaust emissions for small diesel engine by using six types of fuel, which consist of different pure ethanol and butanol volume percentages (10vol.%, 20vol.%), with 3 vol.% surfactant at 20vol.% and 10vol.% aqueous alcohol (ethanol: 65 vol.% or butanol:65vol%, water: 35vol.%) . The combustion behaviors, such as burning pressures, heat release rates and emissions (NOx, Smoke, HC) and fuel consumption are observed. The main conclusions are as follows: 1) NOx and Smoke can be reduced simultaneously by using diesel fuel-alcohol mixed fuel and water emulsion fuel. 2) HC emission decreased by using diesel - butanol mixed water emulsion fuel. 3) The maximum heat release rate is increased by using diesel - alcohol mixed fuel and water emulsion fuel. 4) The heat release stability of diesel - butanol mixed fuel and water emulsion fuel are higher than that of ethanol addition fuels.

The present paper deals with a new defrosting method based on the frost sublimation phenomenon. The focus of the present experimental study is the sublimation mass transfer of a horizontal frost layer exposed to impinging jet flow and radiant energy. It is found that the mass flux of the frost laye rincreases with increasing jet flow velocity and the radiant heat intensity. Non-dimensional correlations for mass transfer, heat transfer and defrosting completion time have been derived in terms of various parameters. ; 冷凍機の蒸発器などの低温熱交換器への着霜は、熱交換器の熱抵抗を著しく増大させ、その性能の低下をもたらすことにより、着霜した熱交換器の性能維持のためには除霜運転が必要となる。著者らは、昇華蒸発現象を利用した新しい除霜法の検討を行っており、水平霜層に対して垂直に湿り低温空気を吹き付ける、いわゆる衝突噴流にさらされた水平霜層の昇華蒸発を利用した除霜挙動を明らかにした。その結果、霜層に平行な強制対流下で除霜する場合と比較して、極めて物質伝達が大きく、短時間での除霜が可能であることが示された。本報は、衝突噴流下で昇華蒸発する霜層にさらに赤外線放射熱エネルギを照射した場合の、昇華蒸発の促進に関する基礎的検討を行うものである。これは、Schmidt や Cunnigham の報告にあるように、霜層の赤外線吸収率が0.98程度と極めて高いことに着目したものである。既報では、水平霜層が平行な強制対流下にさらされる場合について、放射熱エネルギの照射による昇華蒸発促進効果を実験的に検討した。その結果、放射熱エネルギを照射した場合の昇華蒸発量は、放射熱エネルギを照射しない場合に比較して最大10倍程度も増大することが明らかとなり、放射熱エネルギの照射が昇華蒸発促進に非常に有効な方法であることが判明した。本研究は、水平霜層に対して垂直に二次元噴流を衝突させ、さらに赤外線放射熱エネルギをを霜層表面に照射した場合の霜層の昇華蒸発の促進効果に及ぼす赤外線放射強度、二次元噴流空気速度、および空気温度の効果を定量的に検討するものである。