Doctoral Presentation (2022/2) 公聴会. Flow Visualization & Evaporation Control in “Agricultural” Media 植物繊維中の流れの可視化と土壌の蒸発制御


YOSUKE ASANUMA (Grad. School of Bio-Applications and Systems Engineering, Dept. of Food & Energy Systems Science)

Three-dimensional capillary flow visualization and evaporation control in porous media (多孔質媒体中における毛管流れの可視化と蒸発制御)

10 Feb. 2022, 10:30: TUAT/BASE 1F meeting-room. and via ZOOM/Online.

For a recorded video: info (@)

The presentation (about 40 minutes) is prepared in English, but the slides are marked with Japanese for important keywords. Q/A will be available in both English and Japanese. プレゼンテーション(約40分)は英語ですが、スライドに日本語を併記します。質疑応答は英語と日本語の両方で行われます。

Journal Publications related to Doctoral Thesis.

#1. Liquid transport of heated glycerol-water mixtures with colloidal fluorescent particles through multiple biomass layers (Y. Asanuma, T. N. Pratiwi, M. Wada, T. Iwai, I. W. Lenggoro) e-Journal of Surface Science and Nanotechnology (A Journal of The Japan Society of Vacuum and Surface Science) 加熱された複数バイオマス層を通るコロイド状蛍光粒子を有するグリセロール-水混合物の輸送 Open access:

#2. Surface treatment of clayey soil particles for reducing water loss through evaporation (Y. Asanuma, K. Toyota, T. Nishimura, I. W. Lenggoro), Advanced Powder Technology (Journal of The Society of Powder Technology, Japan) 蒸発による水分損失を低減するための粘土質土壌粒子の表面処理 open access. (Before 29 March: elsevier)

Other publication (not-related to Doctoral Thesis):

#3. De-agglomeration of spray-dried particles by ultrasonification (Asanuma, Faizal, Khairunnisa, Lenggoro) 8th Asian Particle Technology Symposium (APT 2021) Online, 2021/10. 超音波による噴霧乾燥粒子の脱凝集 (In revision for a Journal Publication)

Thesis Supervisor: Prof. Wuled Lenggoro

Thesis Examiners: Prof. Hidehiro Kamiya (Particle Technology), Prof. Toshiaki Iwai (Optical Physics), Prof. Koki Toyota (Soil Microbiology), Prof. Yuichiro Nagatsu (Transport Phenomena).

Yosuke Asanuma graduated from TUAT Department of Chemical Engineering (Lenggoro Lab) in 2017, and continued to Master-course in the Department of Bio-Functions and Systems Science, BASE. He joined the Department of Food and Energy Systems Science, for his doctoral course.

Photo by Afif Kusuma on
Photo by James Frid on


The liquid transport process in a porous medium consists of two phenomena, capillary flow and evaporation. The capillary flow is influenced by the interfacial interaction of gas, liquid, and solid. Evaporation process consists of heat transfer, phase change, and mass transfer. Considering the evaporation rate, the thickness of the unsaturated zone due to capillary flow and the liquid continuity have significant effects. The major goal of this thesis is to understand and control the process of liquid transport in porous media. 多孔質媒体中の液体輸送過程は毛管流と蒸発の二つの現象から成る。毛管流は気体,液体,固体の界面相互作用に影響される。蒸発過程は熱伝達,相変化,物質移動からなる。蒸発速度を考慮すると,毛管流による不飽和ゾーンの厚さと液体連続性が重要な効果を持つ。この論文の主な目標は,多孔質媒体中の液体輸送過程を理解し,制御することである。

By reviewing previous studies in various fields with the same direction or purpose, the academic issues and some applications were identified. One of the academic challenges is the establishment of a three-dimensional analytical method (including visualization). The limitations of this analysis method have hindered the accumulation of fundamental knowledge on various gas-liquid-solid interactions. As the application of the “interaction of different phases” has been clearly indicated in various industrial fields, and the complexity of industrial technology requirements has been increasing, understanding the interaction of gas, liquid, and solid has become an important issue. On the other hand, as an example in the agricultural field, water shortage is becoming more serious in some areas due to rapid climate change, and more efficient irrigation methods are required. In this case, the evaporation of water from the soil, which is a porous medium, needs to be controlled.様々な分野におけるこれまでの論文を同じ方向性あるいは目的でレビューすることにより,学術的課題といくつかの応用を特定できた。学術的課題の一つは, 3次元解析法 (可視化を含む) の確立である。この解析法の限界は種々の気体‐液体‐固体相互作用に関する基礎的知識の蓄積を妨げている。様々な産業分野で 「異なる相の相互作用」 の適用が明確に示され,産業技術要求の複雑さが増しているため,気体,液体,固体の相互作用を理解することが重要な課題となっている。一方、農業分野では、急激な気候変動により水不足が深刻化している地域もあり、より効率的な灌漑方法が求められている。この場合,多孔質媒体である土壌からの水の蒸発を制御する必要がある。

In this study, a method was developed to visualize the liquid transport process in a porous medium with a multilayer structure using fluorescent particles. A suspension containing fluorescent particles was permeated into the porous medium, and the behavior of the liquid was estimated from the observation of the fluorescent particles. The effect of heating temperature on the flow of high-viscosity liquid in the porous medium was clarified. It was found that as the viscosity changed with heating temperature, the balance of gravity, capillary force, and viscous resistance changed, affecting the in-plane and out-of-plane behavior of the liquid. Furthermore, an attempt was made to detect “impurities” whose size is on the order of tens to hundreds of nm, which is usually done in a reduced pressure type or vacuum condition. As an application of the developed atmospheric pressure type measurement technique, it was possible to detect the presence of small amounts (tens of nm to hundreds of nm) of impurities that had been intentionally added to the layer.本研究では,蛍光粒子を用いて多層構造の多孔質媒体中の液体輸送過程を可視化する方法を開発した。蛍光粒子を含む懸濁液を多孔質媒体に浸透させ,蛍光粒子の観察から液体の挙動を推定した。多孔質媒体中の高粘度液体の流れに及ぼす加熱温度の影響を明らかにした。粘度が加熱温度と共に変化すると,重力,毛管力,及び粘性抵抗のバランスが変化し,液体の面内及び面外挙動に影響することが分かった。通常は電子顕微鏡のような減圧型や真空型機器で行われるが、本手法により数十〜数百nm程度の大きさの 「不純物」 の検出を試みた。その結果、開発した常圧型「計測」技術は、層に意図的に添加した少量 (数十nmから数百nm) の不純物の存在を検出することができた。

A chemical coating-based method was proposed to control evaporation from agricultural soils (clayey soils). It was confirmed that the wettability of clay soil particles was changed by coating with silane coupling agent. Evaporation experiments were conducted by covering and inserting the original soil with the coated soil. Although the coated soil was less effective in suppressing the diffusion of water vapor, it suppressed the capillary action inside the soil particles and the evaporation flux.農業土壌 (粘土質土壌) からの蒸発を制御するための化学的被覆に基づく方法を提案した。粘土粒子の濡れ性はシランカップリング剤で被覆することにより変化することを確認した。蒸発実験は,被覆土で非コーティング土を被覆・挿入して行った。コーティング土壌は水蒸気の拡散を抑制する効果は低かったが,土壌粒子内部の毛管作用と蒸発フラックスを抑制した。

In this doctoral thesis, a cross-disciplinary literature survey was conducted to identify problems in the interdisciplinary area of agriculture and engineering, and important and urgent issues were carefully selected and experimentally investigated. The proposed three-dimensional visualization of liquid transport in porous media is expected to be useful for accumulating basic knowledge on related processes. As a specific approach to solving problems in the agricultural field, a chemical coating method to control water evaporation from soil on a laboratory scale is also considered. Further research and validation on scaling up are needed for actual application in agriculture. この博士論文では,農業と工学の学際的領域における問題を同定するために学際的文献調査を行い,重要かつ急務な問題を注意深く選択し,実験的に検討した。提案した多孔質媒体中の液体輸送の三次元可視化は,関連するプロセスに関する基礎知識を蓄積するのに有用であると期待される。農業分野での問題を解決するための具体的なアプローチとして,実験室規模で土壌からの水分蒸発を制御する化学的コーティング法も考えられる。農業における実際の応用のためには,スケールアップに関する更なる研究と検証が必要である。

当研究室からの博士論文: Thesis from our Lab

卒業生の活躍「分野」: Sectors of Alumni

卒業生: Alumini Names

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