Nagaoka University of Technology Institutional Repository

国立大学法人長岡技術科学大学博士（工学）Articledoctoral thesi

北原, 雪菜

4213

1 様式Form 論 文 内 容 の 要 旨 Abstract of Dissertation  氏 名Name 北原  雪菜    In recent years, several severe global environmental problems are proceeding and one of the solutions is a shift to a sustainable economic system utilizing biotechnology. Biotechnology utilizing valuable microorganisms can continuously produce food and chemical compounds using bioproducts. Among the production process of bioproducts, the scale-up examination is important for production on an industrial scale. To increase the yield of useful material produced in large cultivations, monitoring the internal environment of a large cultivation tank (jar fermenter) using various sensors in real-time and controlling optimum cultivation conditions based on the results of monitoring are effective. There are various types of indicators for monitoring the jar fermenter. Since microorganisms respond to the extracellular environment and the influence is reflected in the microbial morphology, the microbial morphology may be utilized as a more useful indicator of microbial cultivation than the other conventional monitoring indicator (pH, dissolved oxygen, etc.). However, a trade-off exists between speed and image quality when acquiring morphological information, which it was difficult for the microbial morphology to be acquired at high-definition continuously as well as other sensors. In this thesis, the author aimed to develop a real-time monitoring system in a jar fermenter utilizing microbial morphology.  Chapter 1 describes the background of this research, especially the monitoring method for a large-scale cultivation of microorganism, and mentions the significance of this study. Chapter 2 describes a module that can acquire microbial morphology in high-definition from one-batch cultivation in the jar fermenter by using a microscope, a developed microfluidic device, and a high-speed camera. By using this module, the following points were demonstrated: 1) Images could be acquired with a sufficiently high resolution to observe organelles of cell in the flowing cultivation medium through the microfluidic device. 2) A large number of images could be captured at high speed, and more than 10,000 cell images could be acquired in 2.2 seconds in one take. This image acquiring rate was comparable to cell sorter. The developed module could acquire morphological parameters of microbes in real time like the other general monitoring sensors. Chapter 3 describes the estimation of the culture state (growth or materials productivity) through analysis of images acquired using the developed real-time monitoring system. For image analysis, a deep learning was applied. Oleaginous yeasts were used for the demonstration since these yeasts are some of the most capable for industrial use and insights in the relationship between their morphology and their growth or lipid-productivity has not been clarified. The deep learning image analysis with training data showed a high correlation between the specific cell image and the growth/lipid productivity of the microorganisms. In addition, image analysis using deep learning without training data also confirmed a high correlation between cell image and 2 growth/lipid productivity. Moreover, there seemed to be species-dependent differences in the relationship between the morphology and the state of cells.  Finally, in chapter 4, the results presented in this thesis are summarized and discussed the usefulness of these developed modules and future issues. 

English

Study of a non-invasive real-time monitoring system using microbial morphology in large-scale cultivation

WIJESINGHA, DASANAYAKALAGE UDITHA AKALANKA DASANAYAKA

4222

Local Knowledge Adaptations for Landslide Disasters Risk Reduction in Rural Mountain Communities

PHUNG, NHAT THANH

4220

The Influence of Pulsed Voltage Shape and Period on Active Species Production by Pulsed Discharge

SODIGE BUDDHIKA AMILA KUMARA

1 様式Form 論 文 内 容 の 要 旨 Abstract of Dissertation  氏 名Name SODIGE BUDDHIKA AMILA KUMARA   Nowadays, energy harvesting methods are being developed from natural renewable energy resources owing to the demand for sustainable energy. Especially, piezoelectric, triboelectric, and pyroelectric nanogenerators that convert thermal and mechanical energies could be produced by adding a small-scale physical change into electricity with the usage of digitally enhanced applications.  A novel electro-thermodynamic power generation method that uses Diode and two Switches circuit (DSW circuit) with higher power generation is more efficient than the Olsen electro-thermodynamic cycle method. The temperature differences and the behavior of the external electric field are very important parameters to optimize the amount of generating power. Therefore, the purpose of this study is to improve pyroelectric power generation by using waste heat energy as a renewable energy source in combination with pyroelectric nanogenerators and an external pulse electric field. Under optimal conditions, the maximum power can be accumulated by applying different pulses of the external electric field at temperature variations on the surface of the pyroelectric body since there is no reported pyroelectric power generation experiment in any materials. The experimental process is performed for measuring and calculating to power generation of the pyroelectric body using a newly developed experimental setup based on the modified DSW circuit.  A standard Fuji ceramic C-9 sample was employed to generate pyroelectric power in an environment with continuous temperature variation from low (120 °C) to high (140 °C), with a temperature difference of 20 °C. The continuous temperature variation frequency was 0.05 Hz, and the pulsed electric field was applied when the temperature rose. The pulse width of the electric field 10, 20, 50, 100, and 200 ms pulses were applied to the sample under single pulse and multi-pulse conditions. And the amplitude of the pulses was 250, 500, 1000, and 1500 V/mm. Finally, the maximum power generation condition was evaluated by comparing single-pulse and multi-pulse trains.   The maximum power generated through the application of an external pulsed electric field under the above conditions was evaluated. Finally, a technique for generating pyroelectric energy was devised by applying a pulsed electric field using a pyroelectric body. This power production system had the highest power density of 0.204 mJcm-2°C-1kV-1 in the C-9 sample. Also, for the lowest input power, the maximum power generation condition was a 10 ms pulse width and an amplitude of 250 Vmm-1 in the applied electric field. When applying the multi-pulse to the sample, the power generation density was maximum for the 2 highest number of pulses at the low voltage (250 V/mm) input of the pulse electric field. Furthermore, all the results showed that the power generation rate decreased as the pulsed electric field input voltage rose. The greatest power generating capability ratio (η) value for a 250 V/mm pulse electric field was 7.834 at the highest number of pulses. The results show that the η ratio is greatest for a high number of pulses in a low voltage (250, 500 V/mm) input pulsed electric field. Finally, it was determined that a multi-pulse electric field might enhance the performance of the pyroelectric power generating system. Consequently, this condition might be used to power smart sensor modules, Internet of Things devices, automobiles, and other waste heat energy applications. When the sample is subjected to nano-pulse electric field application, the input power may be lowered to its lowest level depending on the net-producing power. As a result, new researchers can exploit the net-generation power efficiency to develop a large-scale power generation source employing several arrays of pyroelectric materials.                           

Improvement of Power Recovery by Applying Pulse Electric Field of Thermoelectric Cycle Power Generation

赤堀, 弥生

Japanese

天然ゴムの促進硫黄加硫における水の効果

松田, 純一

Study on Electroplating and Electrochemical Properties of Dimethyl Sulfone-Aluminum Chloride Electrolyte with Ammonium Salt

国立大学法人長岡技術科学大学博士（工学）Articlethesi

石川, 真実

4217

1 様式Form 論 文 内 容 の 要 旨 Abstract of Dissertation  氏 名Name 石川 真実   本研究では日常的に口腔衛生を保つ目的として使われる洗口液に着目し，洗口液がもつ生理・心理的効能及び，それら効能に寄与する洗口液の要素について検証を行った．研究1では，ミントを配合した市販洗口液を用いて，就寝前の洗口液使用がその後の睡眠に及ぼす影響を，腕時計型心拍計を用いたフィールド研究により検証した．被験者内計画にて20名の健常な男女を対象とし，被験者は各自宅で就寝直前に一夜ごとにミント感の強さが異なる3つの市販洗口液及び水のいずれかで洗口を行った．評価指標は主観評価に加えて，生理評価指標として腕時計型心拍計による心拍計測および起床時の唾液コルチゾール分析を行った．その結果，いずれの洗口液においても，主観的には就寝前の「疲労感」の低減や「頭のすっきり感」の向上が認められた．また，生理的には，洗口液使用条件においてコントロールと比較して，就寝直後～30分後にかけて心拍数の低下が有意に抑制されたものの，その後は傾向が逆転し，就寝後2時間～6時間ではコントロール条件よりも低い心拍数を維持することが示された．この結果は，就寝時にミント配合洗口液を使用すると，心理的には就寝前にポジティブな気分をもたらし，生理的には睡眠の質を改善することを示唆している．また同研究は，睡眠フィールド研究における新たな方法論としての腕時計型心拍数計の有用性・応用可能性を示した．研究2では，洗口液中のアルコールが末梢及び心臓自律神経系活動に及ぼす影響を計算課題による負荷試験のパラダイムにより検証した．被験者内計画で健常な成人男性20名を対象とし，20分間の計算課題の後，アルコール濃度の異なる洗口液を使用した．それぞれのアルコール濃度は0%，3%，9%の3種類に設定し，コントロール条件は洗口なしとした．評価指標は主観評価に加えて，生理評価指標として皮膚電気活動及び心電図を記録した．その結果，主観的にはアルコール配合の有無を含め条件間に明確な差異は認められなかったものの，末梢の交感神経活性の指標である皮膚コンダクタンスレベルにおいて，アルコール0%及び3%の洗口液は洗口なし条件と比較して計算課題に伴う生理的なストレス応答からの回復効果が大きいことが認められた．これにより，洗口液中のアルコール濃度は使用者の生理に影響を及ぼす因子であることが示唆され，さらに生理ストレス応答からの回復についてはアルコール無配合又は低配合のものが有用であることが示唆された．研究3では、フレーバーの異なる洗口液が及ぼす生理・心理的効果について，研究2と同様に計算課題による負荷試験のパラダイムにより評価した．実験は被験者内計画で行い，健常な成人女性20名が20分間の計算課題の後，それぞれシトラスミントタイプ及びスパイスミントタイプのフレーバーの洗口液を使用した．評価指標は主観評価に加え，生理評価指標として一連の実験の間，皮膚電気活動及び心電図を記録した．その結果，心理的にはサンプル間の差異は認められなかったものの，末梢の交感神経活性の指標である皮膚コンダクタンスレベルにおいて，シトラスミントの方がスパイスミントよりもストレス応答に対する回復効果が大きいことが認められた．これにより，洗口液のフレーバーはアルコール濃度と同様に使用者の生理に影響を及ぼし，さらにシトラスミン2 トタイプのフレーバーはスパイスミントタイプより高い回復効果を有することが示唆された．以上の研究から，洗口液の使用は生理・心理的効能をもたらし，その生理的効能は洗口液中のアルコール濃度やフレーバーなどの構成因子によって異なることが示唆された．洗口液においてアルコール濃度やフレーバーは単に嗜好性を向上させるだけでなく，生理・心理的観点からの処方設計を行うことで，ストレス低減や睡眠改善など消費者の生活の質の向上につながる可能性が見出された．さらに本研究により明らかとなった洗口液の生理・心理的効能は，洗口液使用における薬理効能以外の新たな価値提案につながり，これはオーラルケア意識の低い若年層などへの洗口液使用率や継続モチベーションの向上，ひいては口腔衛生状態の改善をもたらすことが期待される．   

洗口液がもたらす生理・心理的効能

松永, 宏章

アンダーサンプリング型可視光通信の高度化に関する研究

NGO, NGUYEN CHI TRUNG

4214

Development of low-grade waste heat recovery using lead-free pyroelectric Ba(Zr,Ti)O3

長岡技術科学大学博士（工学）doctoral thesi

秀熊,佑哉

炭素繊維接着工法を適用した鋼部材の補修・補強設計法に関する研究

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