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土壌中における炭素鋼の腐食機構に及ぼす水分量の影響
Get PDF多くの太陽光発電システムは基礎構造に鋼製杭を採用しており， 士壌に接する鋼製杭 の腐食速度は土壌によらず， 年間0. 01 mmとされている． しかし， 士壌や埋設深さによ り腐食速度は異なると考えられる． そこで本研究では， 土壌の粒径とその分布が作る環 境（空隙率）の関係を明らかにし， 腐食速度に相関する電荷移動抵抗と土壌環境因子と の相関を明らかにすること， また， 土壌中への酸素の供給パスやその供給速度と土壌環 境因子の相関を明らかにすることで， 土壌中の水分量による腐食機構の解明を目的とし た． 第1章では， 太陽光発電システムの遷移と現状および土壌腐食に関する既往研究のう ち， 土壌中の水分量と通気差が腐食に与える影響についてまとめた． また， 本論文の目 的と構成について述べた． 第2章では， 実際の浅層土壌中に長期的に試験体を暴露することで， その腐食速度を 測定したまた， 土壌を回収し， その土壌を電解質とする交流インピーダンス測定を実 施した． その結果， 多くの土壌， 深度において， 年間0.01 mmの腐食速度を上回ること がわかった． また， 開発した測定セルによる交流インヒ° ーダンス測定が土壌の腐食性評 価に有効であることを述べた． 第3章では， 土壌の粒度分布と土壌中の空隙の関係について調査した． また， その土 壌が作る環境において， 水分呈と腐食速度の関係について述べた． 土壌中の腐食速度は， 埋設された炭素鋼表面と土壌により形成している空隙において， その空隙と気相の割合 （気相率）によって決まり， 気相の割合が大きいほど腐食速度は遅くなることがわかっ た． 第4章では， 士壌中の溶存酸素の拡散を評価して， 土壌が酸素の拡散に与える影響に ついて述べた． 土壌中の酸素の拡散は土壌中の大気を通じて生じており， 気相率と相関 することがわかったまた， 酸素濃度と腐食速度は相関するので， 土壌中では気相率が 高くなると腐食速度は速くなることがわかった． 気相率と腐食速度の関係は， 接液面積を考慮した場合と酸素の拡散速度を考慮した場 合では， 相反する結果を示したそこで， 第5章では， 土壌中では深さ方向で， 乾燥， 降雨による湿潤， より深い土壌への浸透により気相率が異なることから， 気相率の変化 が腐食速度に与える影轡について述べた． 深さ方向の酸素濃度差により電位差が生じ， マクロセル電流が流れるが， 腐食にはほとんど影署しないことがわかった． また， 土壌 腐食において， 接液面積と酸素の拡散速度の両方を考慮した場合， 気相率は10 ~ 15 vol% で腐食速度が最大になることを示唆した． 第6章では， 前章までの結果と考察を踏まえ， 本研究の結論を述べた．博士（工学）琉球大
Computer program written in Mathematica to calculate the spherical growth series of amalgamated free products of infinite cyclic groups
No full textComputer program written in Mathematica to calculate the spherical growth series of amalgamated free products of infinite cyclic group
Endogenous Development in Lao PDR in the Era of Globalization -3 Contrastive Case Studies of External Assistance for a Sustainable Rural Development-
Get PDF本研究は、海外援助を得たミクロレベルの農村開発の３つ事例の分析により、 「Lao Way」の内発的発展という新しい流れをもたらす可能性を論じるものである。研究方法は、海外援助を得たヴィエンチャン近郊の２つの農村（リンサン村とターサン村）と遠隔県の農村（カムペードン村）での比較調査で、質的調査と量的調査を行い、国際社会学の視点から実証的に分析した。これらの調査では、ラオス政府主導のトップダウン型の開発（リンサン村）、ボトムアップ的な特徴をもつ開発（ターサン村）、公衆衛生や栄養問題、教育など基本的ニーズの向上をプライオリティとする開発（カムペードン村）における内発的発展の視点から見た課題を明らかにし、海外援助を得たそれぞれの村が特性に合わせた持続可能な開発にどのように取り組もうとしたのか、その経緯や地域社会における課題解決の方策を量的調査と質的調査で明らかにすることを試みた。結果として、ボトムアップ的な特徴をもつ開発スタイルが内発的発展のために有効であること、そのためには政府や海外援助などの外部からの「サイドサポート」が大きな役割を果たしていること、村における中間レベルのアクターが「Lao Way」をより実践可能な形で叶えるために重要であることが明らかになった。 中間レベルのアクターは国家と地域社会の間で双方の役割やパワーバランスに偏りが出ないような調整役となるだけでなく、村レベルの社会にとっては活動を通して生産力の向上や政府機関と協力体制を築く効果をもたらし、社会主義国のラオスであってもボトムアップ式の開発方法を取り入れることによって、持続可能な内発的発展となる可能性が高いと結論づけた。博士（学術）琉球大学University of the Ryukyu
スマートマイクログリッドにおける再生可能エネルギーのインテリジェントマネジメント管理と柔軟な利用戦略
Get PDFNowadays the world is facing energy crisis and the destruction of the global environment, fossil energy with highC紅hon emission will be gradually replaced by renewable energy with low carbon emission. With the economicdevelopment and social progress, the traditional power generation methods can no longer meet the requirements oftoday's power users fur the reliability and stability of electricity. Micro-grid, which provides lectricity and thermalenergy to the region with distributed power sourc邸such as wind, solar, storage, micro gas turbine, fuel cell andenergy storage systems, can effectively improve the quality of electricity and clear energy consumption, enhance thesecurity and stability of the grid, alleviate the energy crisis and reduce environmental pollution, and even increasethe financial income in the local area. Although microgrid systems are a hot topic in the power sector, the optimalscheduling of distributed micro power sources in micro grids is still a complex technical problem, and the randomvolatility of wind and solar power generation also poses certain safety risks to the microgrid itself. This means thatmicrogrids not only need to realize flexible and efficient application of distributed ener四at the level of low-voltagedistribution system and的Ive the problems of seamless access and grid-co皿ect.ed operation of large and diversedistributed energy sources, but also need precise, intelligent, flexible, safe and reliable energy management andmonitoring. The rapid development of information technology makes all this possible. This thesis, starting fromdistributed power supply. the relationship between the placement of photovoltaic panela and power generation isstudied. It is found that the M·shaped arrangement of solar panels reduces theゎtal power generation. However,the difference between the two becomes sm叫er as the latitude of the placement location decreases. Aa the latitudeinreases, the area used by the M·shape decreases significantly. Then the difference between S- and M·shape powergeneration is compared from the resident.a'consumption. In off-grid operation, S·shape will outperform M-shape,but the difference is small with minimal affect. In grid-connected operation, the difference between the two isessentially the same after a household electricity strategy is developed using the PSO op止平zation algorithm. Thenan optimal operation model based on electric vehicle charging stations is also developed in the thesis. Using theMILP optimization algorithm, the optimal dispatching strategy was developed. The advantages and disadvantagesof the dispatching strategy in the micro grid will directly affect the economy of micro grid operation and the reliabilityof power supply, and it has important theoretical value for the study of microgrid optimal dispatching theory. Theoptimization of equipment combination of microgrid is an important reference standard in the early stage ofconstruction. Due to the rapid development of electric vehicles and _the concentration of people using electric vehicles,the charging time will alao be very concentrated. Therefore, it is necessary to consider the impact on the grid causedby the concentrated time charging of electric vehicles when constructing the microgrid. In this regard, the thesisuses Monte Carlo thinking幻build the corresponding model and gives cha屯ing recommendations.博士（工学）琉球大
両側回遊性ハゼ類における洞窟性種の進化
Get PDFCavefishes have long attracted attention as a model system for evolutionary biology, but knowledge of their natural history background (taxonomy, phylogeny, and ecology) is lacking, except for a few model taxa. Most cavefishes are endemic to a specific cave or region, reflecting population isolation; however, some are known to be geographically widely distributed, and how these taxa evolved has been an enigma. In this study, using the Gobiiformes as a model system, I examined how cavernicolous species with a wide geographic range evolved. The Gobiiformes include both a geographically widespread cave species (an uncertain species of the genus Eleotris) and a species with a regionally limited range (Bostrychus microphthalmus Hoese and Kottelat, 2005). The results of a phylogenetic analysis suggested that both widespread and endemic species evolved from amphidromous ancestors. Otolith microchemistry and population genomic analysis revealed that the widespread Eleotris sp. is currently maintaining an amphidromous lifecycle and is dispersed across a wide area in the Indo-Pacific region. I propose that a habitat preference shift in the larval recruitment to inland water might have initiated speciation. In contrast, the endemic stygobiotic species B. microphthalmus from Sulawesi has lost its dispersal ecology and shows deep divergence from other congeners, suggesting an ancient speciation event. Considering the geographic and faunal background of the region, the species might have become confined to the cave and ceased to migrate as a result of past geographical events. Regardless of the current dispersal ecology, both widespread species and those with limited ranges exhibited common trends for adaptive morphological characters directly related to the cave environment, suggesting irreversible evolution of these characters. After systematic reassessment of the cavefishes and related species and/or genera, both cavefishes and related taxa were found to share specialized neuromast arrangements, suggesting that this is a preadaptive trait. Furthermore, Eleotris eigenmanni Popta, 1921, which has been redescribed as the uncertain cavernicolous Eleotris sp., exhibits phenotypic plasticity in eye diameter. This finding suggests that genetic assimilation of cave-adaptive traits has taken place. Overall, my results suggest that the evolution of cavernicolous species, which originated from amphidromous ancestors, did not solely follow the classic scenario of simple isolation but also involved persistence of their amphidromous ecology. Considering this scenario, the endemic species could have evolved either after rapid landlocking into caves or by a transition from an amphidromous cave species via loss of dispersibility. There may be multiple pathways for the evolution of cave species.博士（理学）琉球大学University of the Ryukyu
アデヤカイロウミウシ属の分類、多様性に関する研究
Get PDFThe genus Goniobranchus Pease, 1866 is a well-supported monophyletic clade that consists of 57 species and they have an ovoid body shape and have different mantle glands underneath their mantle. Certain Goniocranchus species are highly variable in their gross external morphology and this is notably observed in the red-reticulate Goniobranchus spp. and the 'white mantle' Goniobranchus. Both morphological and molecular data were implemented to describe or classify the Goniobrachus nudibranchs in this study.
The molecular analyses of the red-reticulate Goniobranchus spp. identified five species-level clades, but none of the clades' morphotypes matched exactly with the original descriptions of G. tinctorius or G. reticulatus. The existence of multiple species-level clades in the Goniobranchus red-reticulate group suggests this is a group of closely related species, comprising at least five undescribed taxa.
Molecular data of Goniobranchus nudibranchs with white bodies and various marginal bands recovered six species groups corresponding to the described species Goniobranchus albonares, G. preciosus, G. rubrocornutus, G. sinensis and G. verrieri as well as one undescribed species, G. fabulus. Notably, each of G. preciosus, G. sinensis, G. rubrocornutus, G. verrieri, and Goniobranchus fabulus exhibit colour variation and polymorphism, suggesting that colour patterns may not always be useful in the identification of species in the 'white Goniobranchus' group.
The most comprehensive molecular phylogeny of Goniobranchus to date was generated using mitochondrial cytochrome coxidase subunit I (COI), 16S ribosomal DNA (16S rDNA), and the nuclear gene Histone 3 (H3) sequences, with additional Automatic Barcode Gap Discovery (ABGD) and the Bayesian Poisson Tree Process (bPTP) analyses. The analyses recovered 36 described species of Goniobranchus and at least 27 undescribed species. Ten species complexes were recovered in these analyses, and their taxonomic problems were discussed in detail.博士(学術)琉球大
沖縄の人工物上で生育する異質細胞性シアノバクテリアの多様性と系統分類に関する研究
Get PDFMan-made structures such as buildings and guardrails in Okinawa are often stained black or brown, and the main cause is known to be the growth of aerobic cyanobacteria. Previous studies have isolated and cultured aerobic cyanobacteria from the walls of the school buildings on the campus of the University of the Ryukyus, and have found that they are composed of extremely diverse taxa via morphological observations and molecular phylogenetic analyses based on the 16S rRNA gene sequences. The current study focuses on these diverse aerobic cyanobacteria, and especially Nostocales cyanobacteria, which are known to have nitrogen-fixing ability via heterocytes, and their diversity and phylogenetic classification have already been established. In addition to already isolated strains, new isolates were added during this study. This thesis is divided into five chapters. Chapter 1 summarizes the current classification of cyanobacteria and outlines the latest polyphasic taxonomy research methods. The current classification of cyanobacteria is based on the 16S rRNA gene based on Komárek et al. (2014) and accurate morphological classification. Chapter 2 shows the classification of filamentous cyanobacteria involved in black band disease, which is one of the coral diseases in Okinawa, as an example of research on polyphasic taxonomy research. As a result, we succeeded in analyzing the 16S rRNA gene sequences of cyanobacteria collected from the Okinawajima and Miyakojima islands by the single filament PCR method, and there were almost no differences among samples, which were identified as Roseofilum reptotaenium. Culture strains were also successfully established. In Chapter 3, in addition to the culture strains established in the previous research from the campus of the University of the Ryukyus, we newly established isolated strains from artificial objects such as guard rails and building walls in Okinawa, containing diversified heterocystous aerobic cyanobacteria. The strains were analyzed by molecular phylogenetic analyses based on the 16S rRNA sequences and light microscopic observations. This study found 12 groups that were difficult to morphologically distinguish, and revealed that is highly possible that undescribed taxa were included. Chapter 4 examined the genus Brasilonema among the various heterocystous cyanobacteria clarified in the previous chapter, and showed phylogenetic classification by morphological observations and 16S rRNA and 16S-23S ITS analyses. Chapter 5 gives a summary of this study and future prospects.博士(学術)琉球大
亜熱帯沖縄における建物の熱環境とエネルギー消費に関する研究
Get PDFThis dissertation is an integration of several studies on thermal environment and energy consumption in buildings including surveys of existing buildings, characteristics of climate and environmental technologies for energy saving in subtropical Okinawa. The contents consist of the following 4 studies: 1) Surveys of various energy consumption of real existing buildings, 2) Heat protection on rooftops for reduction of cooling load, 3) Cooling trench under the basement for reduction of air conditioning load, 4) Practical conditions of energy saving buildings and effects of ESCO. The first, 1) is a study on detailed energy consumption in houses all through the year to examine the characteristics of energy use in houses and possibility of energy saving. The second, 2) is an estimation of reduction of cooling load, energy saving and cost-cutting for energy by thermal protection on rooftops from direct solar radiation that are weakest parts of cooling load based on a survey of a real existing building. The third, 3) is examination of the effect of cool trench that is called Earth tube in this study through a full-scale measurement in a building with an Earth tube to clarify its performance in subtropical Okinawa. The fourth, 4) is an evaluation of improvement of buildings for energy saving, especially ESCO projects, to examine its efficiency through some surveys. The targets of the surveys were various types of buildings, public, office, hotel, commercial, factory, school and hospital, except residential houses in Okinawa and in Hawaii to compare each other. The practical energy consumption and thermal environment in the buildings, awareness and actions of energy saving were surveyed in Okinawa and Hawaii.
Main results from these researches are as follows: the most energy consuming factor in residential houses in Okinawa is hot water supply, while that in non-residential buildings is air-conditioning system. Therefore, energy saving in non-residential buildings is almost the same meaning as reduction of air conditioning, especially cooling load in subtropical zones. For this purpose, thermal protection on rooftops and ESCO projects were found effective to achieve every saving, although the Earth tube was not. Awareness of energy saving was high both in Okinawa and Hawaii. However, Energy saving actions in Okinawa were basically occupants’ voluntary behavior, while those in Hawaii depended on the energy efficiency of building equipment and appliances. These conclusions are significant basic documents for the realization of energy saving buildings besides net Zero Energy Buildings (ZEB).博士（工学）琉球大
日本産ボラ科魚類の同定と生態に関する研究
Get PDFボラ科魚類は日本から 8属 16種が報告されており，水産重要種や希少種を含む．また，その卓越した現存量によって，沿岸生態系を支える重要な分類群でもある．しかし，本科魚類は形態が著しく類似しており，分類学的な混乱が見られる．特に，同定に重要な形質が未発達，あるいは破損しやすい稚魚期においては形態に関する知見が乏しく，同定が極めて困難である．よって，本科魚類の分布情報や生態に関する知見はおそらく混乱しており，水産利用や保全策を策定する上で必要不可欠な基礎的知見が欠落している．正確な同定方法の開発とその分布・生態に関する知見の収集は，本科魚類を持続的に利用していく上で喫緊の課題である．
そこで，第 1章では DNAバーコーディングを用いて分類学的単位 (OTU) として本科魚類の多様性を把握したのち，形態観察を行い OTU 間の同定方法を開発した．また，本邦産本科魚類の分類を総括した瀬能 (2013) と各 OTU がどのように対応するのかを検討した．DNAバーコーデイングの結果， 23OTU が確認された．これらの OTU は形態によって識別が可能であるか，同所的に生息しており，形態的種概念あるいは生物学的種概念を満たすことから，種として扱うことが妥当であると考えられた．稚魚の標本が得られた 19種について形態を検討した結果，タイワンメナダ種群間 (2種) とボラ種群間 (3種) 以外については形態により識別が可能であることが判明した．
また，第 2章では沖縄島と西表島においてメナダ属 3種の生活史に関する知見を集積した．その結果，以下のような違いが見られた；最大体長 1) 最大体長：雌 242mm，雄 215mm SL vs 雌 200mm，雄 154mm SL vs 雌 204mm SL，雄 146mm SL (コボラ vs セスジボラ vs ヒルギメナダ)；2) 最高齢：雌 8歳，雄 5歳 vs 雌 5歳，雄 2歳 vs 雌 7歳，雄 3歳；3) 最小成熟年齢：雌 2歳，雄 2歳 vs 雌 1歳，雄 1歳 vs 雌 2歳，雄 1歳；4) 産卵期：11-5月 vs 123月 vs 12-3月を含む；5) 加入期：1-5月 vs 2, 3月 vs 1-3月を含む．また，ヒルギメナダの稚魚はマングロープに集中して出現することが判明した．このような生活史特性の違いは，本科魚類の多様性を維持する上で重要な役割を担っている可能性がある．
第 3章では 1章と 2章の結果を踏まえ，八重山諸島の固有種である可能性が高いヒルギメナダや ROB 掲載種の保全ランク，水産重要種として利用されているボラ種群の保全策について議論した．博士(理学)琉球大
沖縄県の伝統木造住宅における構造性能評価に関する研究
Get PDF本論文は沖縄県の伝統木造住宅に関する既往論文を統括的に分析し、その特徴と変遷を整理するとともに重要文化財に指定されるような伝統木造住宅の現状における部材劣化および振動特性を分析したものである。また、この分析と併せて構造解析を行い、簡便な構造性能調査法の確立に向け基盤となるデータベースを作成することを目的としている。
本論文は以下の六章で構成されている。
第一章では日本の伝統木造住宅に対する構造評価の変遷および、沖縄県における伝統木造住宅の現状についてまとめ、また、本論文の目的、調査対象建築物について述べた。
第二章では沖縄における伝統木造住宅に関する既往論文を統括的にまとめ、その特徴や変遷について述べた。
第三章では第一章で述べた重要文化財に指定されるような伝統木造住宅を対象に現況の部材ヤング係数を推定すべく非破壊による応力波伝播速度測定を行った。調査の結果から保存状態の良いイヌマキ部材のヤング係数は新材と同等な値となり、 経年による劣化は見られなかった。
第四章では第三章と同様の対象物件で振動特性を把握することを目的に常時微動測定を行った。沖縄における伝統木造住宅の平均的な固有振動数は 2.5Hz～2.8Hz付近に見られ、特に保存状態が悪い住宅では健全なものと比べ 1Hz程振動数が少なくなった。また、建物の固有振動数は降雨による湿気の影響で睛天時と比べ 1Hz程上昇する傾向が確認でき、台風時等の外力が働く際は、接合部が密になり剛性が増すことが示された。
第五章では現在普及している耐震マニュアルを参考に第三章および第四章で調査した建物の中から二物件に対し限界耐力計算を用いた構造性能評価を行い耐震性能及び耐風性能を検討するとともに耐久性能を補強する上で必要な耐力要素についてシミュレーションを行い、提案をした。沖縄における伝統木造住宅は外壁が少なく、開口部の多さが弱点となり耐震性能が不十分である物件があることが示唆された。前章で述べた固有振動数の値は、今回構造解析を行った 2物件とその他の物件とで固有振動数に大きな差異は見られなかったことから他の沖縄における伝統木造住宅においても地震に対して十分な耐力を有していないことが考えられる。
第六章では前章までの考察を踏まえ本研究の結論および今後の課題をまとめた。博士（工学）琉球大