本論文では，化学気相蒸着（CVD）装置におけるガス入口と加熱基板間の距離（H_N^*）およびノズルレイノルズ数（Re_N）が熱流動に及ぼす影響を調査するために，衝突噴流をともなう円筒流路内の加熱基板上の水平断面における温度測定が行われた。さらに，CVD反応器内におけるr軸方向の成膜速度分布を予測するために，加熱基板上の熱および物質移動の二次元数値シミュレーションが行われた。H_N^*が小さいほど衝突噴流の影響が強まるため，r^* = 0 mmにおける温度の実験値は低くなった。r 方向の温度の計算結果は，HN^* = 0.69におけるr^* = 0の場合を除き，実験結果とよく一致した。無次元の表面反応速度定数k^*が3.60×10^-9 ≦k^* ≦1.27×10^-7（k = 10^-6 m/s）のとき，加熱基板上の原料の計算による成膜速度は，半径方向に沿った拡散律速で膜形成が進行する可能性があるため，r方向に沿って指数関数的に減少した。一方，基板中央部において，ノズルからの強制対流による物質移動が3.60×10^-9 ≤ k^* ≤ 1.27×10^-7の場合よりも0.036 ≤ k^* ≦ 0.126（k = 1 m/s）の場合の方が影響を受けやすく，成膜速度は大幅に減少した。H_N^*が大きくなるほど物質移動は表面反応律速に近づくことが考えられるため，0 ≤ r^* ≤ 3.45におけるr 方向の成膜速度の勾配は小さくなる。H_N^*が大きく反応速度が小さくなるほど，成膜速度の変動係数は小さくなる。本研究では，成膜速度分布の変動係数の最小値は約0.41だった。したがって，衝突噴流だけでなくシャワーヘッド流からのCVD原料のハイブリッド供給システムが適切である可能性があることが示唆された。

Vertically aligned MoS₂ (V-MoS₂) thin film was investigated to achieve a cost-effective hydrogen evolution reaction (HER) catalyst. As a simple method, the V-MoS₂ film was deposited by partial sulphurisation of RF sputtered Mo film. The residual Mo layer was used as a bottom electrode instead of an expensive conductive substrate such as a glassy carbon. Different thicknesses of V-MoS₂ were deposited to investigate an HER catalyst characteristic for the V-MoS₂/Mo structure. The crystallinity of V-MoS₂ was maintained even though the thickness of V-MoS₂ was controlled, and was confirmed by comparing the X-ray diffraction, Raman measurement, and estimated exchange current density. As the thickness of V-MoS2 was decreased to 50 nm, the overpotential and Tafel slope were reduced to 0.38 V at 10 mA/cm² and 87 mV/dec, respectively. Based on the theoretical tendency of Tafel slope decline, the estimated optimal V-MoS2 thickness was 40 nm for the V-MoS₂/Mo structure. The fabrication process for V-MoS₂ and the estimated result from the variation of the thickness of V-MoS2 could help to realise a cost-effective HER catalyst using MoS₂.

Ammonia is an essential waste from fish and shrimp which has an effect on fish and shrimp transportation for export. This study aimed to remove ammonia by Activated Carbon adsorption. The activated carbon was prepared from Tamarind pulp using different methods (NaOH, H₂SO₄, the hydrothermal technique and activated by H2SO4 and H2SO4 hydrothermal followed by NaOH). The Activated Carbon was characterized by and Iodine number and Fourier Transform Infrared Spectroscopy (FT-IR). The results showed that the iodine number of activated carbon prepared by the hydrothermal technique and activated by H2SO4 have the highest surface area and porosity at 537 mg/g, and the functional group on activated carbon surface is carbonyl and sulfonyl group. For ammonia adsorption, the experiments were designed by Box-Behnken design at 3 factors 3 levels including Contact time (10, 95 and 180 min), Dosage of activated carbon (0.5, 1.25 and 2.0 g) and pH of the solution (2, 6.5 and 11). The concentration of ammonia was determined by UV-Visible spectrophotometer. The result showed that the main effects and the interaction effects were found significant effect on ammonia adsorption at confidence level of 95%. However, the interaction effects between contact time and activated carbon dosage was insignificant. Finally, the optimized results suggested that 48.32 ± 0.82% of ammonia concentration could be removed by activated carbon from tamarind pulp under the following conditions: pH of 11, a contact time of 95 min, and activated carbon dosage of 2 g/100 mL. The results are believed to be of importance to fish and shrimp transportation for reduced ammonia and other similar applications.

本研究は，将来の環境対策の一環としてバイオマス由来の水素を貯蔵し，様々なアプリケーション（燃料電池アシスト自転車，ドローン，定置用等）に適用する事が有望視されている事を鑑み，水素吸蔵合金を利用した水素貯蔵タンクについての解析を行った。水素吸蔵合金とは水素と可逆的に反応する合金である。水素吸蔵合金は，水素の貯蔵時圧力が低いため，安全性向上や水素充填時の圧縮動力の低減に貢献可能である。一方で，水素吸蔵合金への水素充填時の発熱反応による温度上昇が原因となり反応速度が低下するため，水素の充填時間が長くなり，運用面での不便さが生じてしまう懸念がある。その対策として，水素吸蔵合金を冷却し，反応速度の大きくする事が有望視されている。

このような背景を踏まえ，本研究では環境負荷低減を目途に，水素吸蔵合金と圧縮水素（現在主流の水素貯蔵方法）の水素充填時の圧縮動力の比較を行った。また，水素充填時間が長いという運用面における懸念点の解消を目途に，水素吸蔵合金への水素充填プロセスの非定常２次元数理モデルを開発し，異なる冷却温度条件下（タンク周囲温度：233，253，273，298 K）でのシミュレーションを行う事で，水素吸蔵合金の冷却が水素充填時間に及ぼす影響を評価した。その結果，水素吸蔵合金を利用した水素貯蔵は，従来の圧縮水素に比して，水素充填時の圧縮動力を最大で7.57 kWh/kg-H₂低減する事が示唆された。また，水素吸蔵合金タンクから反応熱を除去することで，水素充填時間を短縮できることが示唆された。例えば，タンクの周囲温度273 Kのとき，水素充填時間（水素貯蔵量: 最大水素貯蔵量の70%）が1,902秒であったのに対して，886 s（周囲温度：233 K）まで短縮できるという知見を得た。

The palm fatty acid distillate (PFAD), as a low-cost feedstock, was catalytically esterified into biodiesel (also known as fatty acid methyl ester, FAME) using sulfonated iron oxide (HSO₃ˉ/Fe₂O₃) catalyst. In this work, the catalyst was synthesised via self-propagating combustion (SPC) method, towards a greener synthesis technique, followed by sulfonation with chlorosulfonic acid (HSO₃Cl) to enhance the catalyst’s acid properties. The catalysts were characterised and the success of sulfonation process was determined. From this study, Fe₂O₃ catalysts were proven to be pure and single-phase. The success of the sulfonation then was verified by the presence of sulfur, functional groups of S-O asymmetric vibration and S=O symmetric vibration, and increasing total acidity. Then, the sulfonated Fe₂O₃ catalyst was used to esterify the PFAD feedstock in methanol in which the esterification parameters were also optimized to obtain maximum free fatty acid (FFA) conversion. It was found that 15:1 of methanol-to-PFAD molar ratio, 4 wt.% of catalyst loading, 80 °C of reaction temperature and 5 h of reaction time produced 95.5% of FFA conversion. Interestingly, the sulfonated Fe₂O₃ catalyst can be considered as a superacid solid catalyst that enables boosting the esterification of the PFAD feedstock into biodiesel.

The preparation and characterization of purified cellulose from bamboo shoot shell were studied using fouriertransform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The preparation of cellulose fiber included extraction of cellulose from bamboo shoot shell by treatment with 5 % NaOH and 4 % H₂O₂, and purification of cellulose fiber using hydrothermal technique. The result showed that cellulose has been successfully extracted at a 32.56% yield by the 5% NaOH / 4% H2O2 treatment, and the purified cellulose was produced using autoclaving at the temperature of 120 °C and pressure at 0.1 MPa for 2 h 5 min, with the % recovery of purified cellulose around 94.08. Bamboo shoot shell and cellulose sample were further characterized using FTIR technique. It was found that the 5% NaOH / 4% H₂O₂ treatment eliminated lignin and hemicellulose from bamboo shoot shell but did not affect cellulose. The hydrothermal technique did not affect the destruction of the cellulose structure as well. Comparison of the SEM image showed that cellulose was separated into individual microfibers after the 5% NaOH / 4% H₂O₂ treatment while the SEM image of purified cellulose was the small thread-like fibers with smoother surface. Therefore, hydrothermal treatment can be performed for purification of cellulose.

The present work aims to study the catalytic performance of kaolinite (KN)-supported TiO₂ in the production of dimethyl ether (DME) from methanol. KN was doped with 0, 3, 5, 10, and 15 wt% Ti composite particles via the sol-gel method. The performance of the TiO₂/KN catalysts were then tested in a fixed-bed reactor having a temperature in the range 200-350 °C under atmospheric pressure. The molar ratio of methanol to nitrogen, total gas flow rate, and weight hourly space velocity (WHSV) were set to 1:4, 60 mL/min at standard temperature and pressure, and 2.054 h^-1, respectively. The catalysts were characterized using scanning electron microscopy, the Brunauer-Emmett-Teller method, X-ray diffraction, and temperature-programmed desorption of NH₃. The final products were analyzed using gas chromatography. An increase in Ti loading yielded a higher methanol conversion rate owing to the increase in the number of acid sites on the catalyst surface. The highest methanol conversion rate of 79% was reported for TiO₂/KN (Ti=15%) at 350 °C. However, TiO₂/KN (Ti=15%) exhibited low selectivity to DME owing to the decomposition of DME to CH₄ and CO₂. Our results indicate the optimum Ti loading to be TiO₂/KN (Ti=10%), which resulted in a catalyst that was active at 250 °C and showed good selectivity to DME.