Enhanced stabilisation of simulant organic nuclear wastes in metakaolin-based geopolymers using graphene oxide
Sivasubramaniam Seralathan, Xiaobo Niu, Yogarajah Elakneswaran, Chewei Fang
Applied Clay Science, 271, 107793, 107793, Elsevier BV, 2025年07月
研究論文（学術雑誌）

Correlating strength development with hydration characteristics for multi-blend fly ash concrete
Yuguo Yu, Chamila Gunasekara, Yogarajah Elakneswaran, Dilan Robert, David W. Law, Sujeeva Setunge
Journal of Building Engineering, 103, 112076, 112076, Elsevier BV, 2025年06月
研究論文（学術雑誌）

Incorporation of boron into metakaolin-based geopolymers for radionuclide immobilisation and neutron capture potential
Xiaobo Niu, Yogarajah Elakneswaran, Ang Li, Sivasubramaniam Seralathan, Ryosuke Kikuchi, Yoshihisa Hiraki, Junya Sato, Takeshi Osugi, Brant Walkley
Cement and Concrete Research, 190, 107814, 107814, Elsevier BV, 2025年04月
研究論文（学術雑誌）

CO2 sequestration and low carbon strategies in 3D printed concrete
Kirushnapillai Kopitha, Pathmanathan Rajeev, Jay Sanjayan, Yogarajah Elakneswaran
Journal of Building Engineering, 99, 111653, 111653, Elsevier BV, 2025年04月
研究論文（学術雑誌）

Influence of amorphous content in recycled fly ash on binder hydration characteristics
Yuguo Yu, Chamila Gunasekara, Yogarajah Elakneswaran, Dilan Robert, David W. Law, Sujeeva Setunge
Journal of Material Cycles and Waste Management, Springer Science and Business Media LLC, 2025年01月07日
研究論文（学術雑誌）, Abstract

Greening of the construction sector has witnessed the widespread practice of recycling fly ash into building materials for decades. The control of ash waste quality is an important aspect for its viability as a supplementary cementitious material, where the detailed physical and chemical characteristics play crucial roles. To better facilitate informed greener design, a novel method is leveraged to study particularly the influence of amorphous content in fly ash on binder hydration. In this study, a coupled kinetic-thermodynamic approach is implemented to realise comprehensive hydration assessment. The adopted kinetics-based model is developed following unified theory to quantify the hydration/reaction degrees for cement and fly ash. Such kinetic information is further utilised in thermodynamic analysis, powered by Gibbs energy minimisation method, to evaluate the time-dependent phase assemblage of cementitious system upon continuous hydration. The applied technique is carefully verified against a series of reported tests, before further exploited to conduct numerical explorations. Computational findings highlight the influence of amorphous content in fly ash on the chemo-physical–mechanical properties of concrete products, providing insights for future sustainable construction material design.

Alkaline ethanolamine as dual-functional agent: Effective CO2 capture agent and corrosion inhibitor for structural applications
Govindaraj Yoganandan, Ryosuke Saito, Keiichi Yano, Masatoshi Sakairi, Koji Fushimi, Ryoma Kitagaki, Yogarajah Elakneswaran, Hisanori Senboku, Yuya Yoda, Masato Tsu-jino, Akira Nishida
Chemical Engineering Journal, 504, 158810, 158810, Elsevier BV, 2025年01月
研究論文（学術雑誌）

Immobilisation of iodide in alkali-activated materials
Raudhatul Islam Chaerun, Manami Ishimura, Pramesti Prihutami, Xiaobo Niu, Yusuke Ohya, Kazuma Kuroda, Kanako Toda, Ryosuke Kikuchi, Tsubasa Otake, John L. Provis, Yogarajah Elakneswaran, Tsutomu Sato
Chemosphere, 369, 143871, 143871, Elsevier BV, 2024年12月
研究論文（学術雑誌）

Enhancing CO2 capture in cement-based materials with alkanolamines: A comprehensive study on efficiency, phase-specific impact, and carbonation mechanisms
Kirushnapillai Kopitha, Yogarajah Elakneswaran, Ryoma Kitagaki, Ryosuke Saito, Keiichi Yano, Yuya Yoda, Masato Tsujino, Akira Nishida, Hisanori Senboku, Koji Fushimi, Masatoshi Sakairi
Science of The Total Environment, 957, 177463, 177463, Elsevier BV, 2024年12月
研究論文（学術雑誌）

On the hydration of limestone calcined kaolinitic clay cement and energy-efficient production
Yuguo Yu, Chamila Gunasekara, Yogarajah Elakneswaran, Dilan Robert, David W. Law, Sujeeva Setunge
Cement and Concrete Composites, 153, 105698, 105698, Elsevier BV, 2024年10月
研究論文（学術雑誌）

Exploring the reinforcing mechanism of graphene oxide in cementitious materials through microstructural analysis of synthesised calcium silicate hydrate
Mylvaganam Nithurshan, Yogarajah Elakneswaran, Yuya Yoda, Keiichi Yano, Ryoma Kitagaki, Naoki Hiroyoshi
Cement and Concrete Composites, 153, 105717, 105717, Elsevier BV, 2024年10月
研究論文（学術雑誌）

Influence of inorganic solid particles on the stability of water-in-crude oil emulsions: Evaluating the role of surface charge
Tokima Hattori, Yogarajah Elakneswaran, Xingjuan Hao, Mai Shimokawara, Naoki Hiroyoshi
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 699, 134726, 134726, Elsevier BV, 2024年10月
研究論文（学術雑誌）

Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete
Susan A. Bernal, Yuvaraj Dhandapani, Yogarajah Elakneswaran, Gregor J. G. Gluth, Elke Gruyaert, Maria C. G. Juenger, Barbara Lothenbach, Kolawole A. Olonade, Marlene Sakoparnig, Zhenguo Shi, Charlotte Thiel, Phillip Van den Heede, Hanne Vanoutrive, Stefanie von Greve-Dierfeld, Nele De Belie, John L. Provis
Materials and Structures, 57, 8, Springer Science and Business Media LLC, 2024年09月03日
研究論文（学術雑誌）, Abstract

The chemical reaction between CO₂ and a blended Portland cement concrete, referred to as carbonation, can lead to reduced performance, particularly when concrete is exposed to elevated levels of CO₂ (i.e., accelerated carbonation conditions). When slight changes in concrete mix designs or testing conditions are adopted, conflicting carbonation results are often reported. The RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ has conducted a critical analysis of the standardised testing methodologies that are currently applied to determine carbonation resistance of concrete in different regions. There are at least 17 different standards or recommendations being actively used for this purpose, with significant differences in sample curing, pre-conditioning, carbonation exposure conditions, and methods used for determination of carbonation depth after exposure. These differences strongly influence the carbonation depths recorded and the carbonation coefficient values calculated. Considering the importance of accurately determining carbonation potential of concrete, not just for predicting their durability performance, but also for determining the amount of CO₂ that concrete can re-absorb during or after its service life, it is imperative to recognise the applicability and limitations of the results obtained from different tests. This will enable researchers and practitioners to adopt the most appropriate testing methodologies to evaluate carbonation resistance, depending on the purpose of the conclusions derived from such testing (e. g. materials selection, service life prediction, CO₂ capture potential).

Influence of Reservoir Salinity, Mineralogy, Temperature, and Pressure on Geochemical Hydrogen Loss in Depleted Carbonates
Angelo Kennedy Lino Limaluka, Elakneswaran Yogarajah, Naoki Hiroyoshi, Moataz Abu-AlSaud, Dong Kyu Cha, Subhash C. Ayirala
SPE Journal, 29, 10, 5690, 5701, Society of Petroleum Engineers (SPE), 2024年07月29日
研究論文（学術雑誌）, Summary

Underground hydrogen storage (UHS) is a cost-effective and safer system vital for the growth of the hydrogen market and its role as an essential transitional fuel. Presently, depleted hydrocarbon reservoirs (DHR) account for more than 75% of all UHS sites due to their higher prevalence and readiness for use. However, hydrogen (H2) loss primarily due to abiotic interactions poses a significant challenge to the integrity of DHR sites, and while the underlying conditions have been investigated in some studies, the conclusions have been inconsistent, particularly for carbonate reservoirs. In this study, we analyzed the impact of reservoir physical and chemical parameters, (i.e., salinity, mineralogy, temperature, and pressure) on H2-brine-mineral interactions and the extent of H2 loss in carbonate formations. Static batch simulations were performed using PHREEQC and MATLAB® for a 1-year storage cycle period with three different brine and rock samples at 50–130°C and 15–30 MPa. The results showed that the dissociation of H2 and formation of CH4 and H2S increased with increasing temperature, at a two times higher rate compared to pressure. Also, markedly, in various brine compositions and reactive mineralogy, a 20% or less H2 loss could be attained in temperatures <50°C and 115–130°C, with pressure below 17 MPa; meanwhile, the pressure condition 18 MPa and greater (at 50°C) would risk at least 50% loss, with >86% from 19 MPa. Second, H2 loss increased to 80% after about 50 days for all the brines, and pressure and temperature conditions in the mineral sample with the largest composition of reactive minerals (i.e., pyrite, anhydrite, etc.) suggested a 50% loss risk in such mineralogy during the storage cycle period of about 1 month. Lastly, in the mineral sample with >90 wt% calcite and 0–2 wt% reactive minerals composition, H2 molality increased at least fourfold on average across the storage period and reservoir brine/temperature/pressure conditions. This result further indicates that reactive mineralogy has a more significant effect on the stability of hydrogen relative to temperature and pressure in a carbonate UHS formation. In summary, the findings suggest that a minimal reactive mineral composition, 100°C or higher, and 17 MPa or lower constitutes a set of reservoir physical and chemical conditions with the potential for a limited risk of H2 loss (<20%) in carbonate DHR. However, the extension of the present work to the dynamic UHS conditions is necessary to further ascertain these conclusions.

Surface chemistry and radionuclide anion immobilisation potential of phosphoric acid-activated metakaolin-based geopolymers
Xiaobo Niu, Yogarajah Elakneswaran, Naoki Hiroyoshi
Cement and Concrete Research, 181, 107549, 107549, Elsevier BV, 2024年07月
研究論文（学術雑誌）

Unified hydration model for multi-blend fly ash cementitious systems of wide-range replacement rates
Yuguo Yu, Chamila Gunasekara, Yogarajah Elakneswaran, Dilan Robert, David W. Law, Sujeeva Setunge
Cement and Concrete Research, 180, 107487, 107487, Elsevier BV, 2024年06月
研究論文（学術雑誌）

Role of Semiconductive Property on Selective Cementation Mechanism of Iron Oxides to Gold in Galvanic Interaction with Zero-Valent Aluminum from Gold–Copper Ammoniacal Thiosulfate Solutions
Joshua Zoleta, Kosei Aikawa, Nako Okada, Ilhwan Park, Mayumi Ito, Yogarajah Elakneswaran, Naoki Hiroyoshi
Metals, 14, 5, 550, 550, MDPI AG, 2024年05月07日
研究論文（学術雑誌）, Iron oxides (hematite, Fe2O3, and magnetite, Fe3O4), previously used as electron mediators in the galvanic system with zero-valent aluminum (ZVAl), have been shown to recover Au upon cementation in Au–Cu ammoniacal thiosulfate media selectively, and this warrants further investigation. This research is focused on investigating the role of the semiconductive properties of metal oxides by performing a cementation experiment by mixing 0.15 g of electron mediators (Fe3O4, Fe2O3, TiO2 (anatase and rutile)) and 0.15 g of zero-valent aluminum powder as an electron donor in various electrochemical experiments. The results revealed that upon the cementation experiment, synthetic Fe2O3 and Fe3O4 were consistently able to selectively recover Au at around 90% and Cu at around 20%. Compared to activated carbon (AC), TiO2, in anatase and rutile forms, obtained selective recovery of gold, but the recovery was utterly insignificant compared to that of iron oxides, obtaining an average of 93% Au and 63% Cu recovery. The electrochemical and surface analysis supports the results obtained upon the cementation process, where TiO2, upon cyclic voltammetry (CV), obtained two reduction peaks centered at −1.0 V and −0.5 V assigned to reducing Au and Cu ions, respectively. Furthermore, various electrochemical impedance spectroscopic analyses revealed that the flat band potential obtained in the Mott–Schottky plot is around −1.0 V and −0.2 V for iron oxides and titanium oxides, respectively, suggesting that the electrons travel from semiconductor interface to electrolyte interface, and electrons are accessible only to Au ions in the electrolyte interface (reduction band edge around −1.0 V). The determination of this selective cementation mechanism is one of a kind. It has been proposed that the semiconductive properties of Fe2O3, Fe3O4, and, by configuring their relative energy band diagram, the travel of electrons from the iron oxide–electrolyte interface facilitate the selective cementation towards Au(S2O3)23+ ions in gold–copper ammoniacal thiosulfate solutions.

Macroscale Modeling of Geochemistry Influence on Polymer and Low-Salinity Waterflooding in Carbonate Oil Reservoirs
Angelo Kennedy Lino Limaluka, Yogarajah Elakneswaran, Naoki Hiroyoshi
ACS Omega, American Chemical Society (ACS), 2024年04月05日
研究論文（学術雑誌）

Multiscale computational modelling of nano-silica reinforced cement paste: Bridging microstructure and mechanical performance
Mylvaganam Nithurshan, Yogarajah Elakneswaran, Yuya Yoda, Ryoma Kitagaki, Naoki Hiroyoshi
Construction and Building Materials, 425, 136047, 136047, Elsevier BV, 2024年04月
研究論文（学術雑誌）

Development and verification of an integrated hydration, geochemical and transport model for the hydrated cement paste exposed to an aggressive chemical environment
Siventhirarajah Krishnya, Kirushnapillai Kopitha, Yuya Yoda, Ryoma Kitagaki, Yogarajah Elakneswaran
Cement and Concrete Composites, 146, 2024年02月
研究論文（学術雑誌）

Effect of Superabsorbent Polymer (SAP) Size on Microstructure and Compressive Strength of Concrete
Xiaobo Niu, Yile Zhang, Yogarajah Elakneswaran, Miyu Sasaki, Takeshi Takayama, Hajime Kawai
Polymers, 16, 2, 197, 197, MDPI AG, 2024年01月09日
研究論文（学術雑誌）, Superabsorbent polymers (SAPs) are hydrophilic, polymeric network materials renowned for their ability to enhance various properties of cementitious materials. This investigation examines the impact of SAP size on the hydration degree, porosity, and compressive strength of cement pastes and concrete under diverse curing conditions and ageing periods. The findings reveal that SAP addition stimulates the hydration of the C2S phase, particularly during the early curing stages, thereby favouring early strength development. However, the effect of SAPs on hydration promotion diminishes as their size increases. Conversely, the size of SAPs affects the hydration range of their action, and the 400 µm SAP demonstrates the most extensive range of hydration enhancement, reaching up to 105 µm. Additionally, SAPs effectively reduce porosity in small pores (4 nm–10 μm), with 200 μm and 400 μm SAPs exhibiting the highest efficacy. While analysing the effects of SAPs on larger pores (>10 μm), the results show that although larger SAPs result in larger average porosity, the total porosity is effectively reduced, particularly in samples incorporating 400 μm SAP. The compressive strength of cement paste, even after 28 days, is slightly reduced following the introduction of SAPs. However, the strength of concrete, due to the naturally occurring pores eliminating the negative effects of the pores produced by SAPs, is significantly increased following the introduction of SAPs, especially 400 µm SAP.

Development of metakaolin-based geopolymer for selenium oxyanions uptake through in-situ ettringite formation
Xiaobo Niu, Yogarajah Elakneswaran, Raudhatul Islam Chaerun, Chuwei Fang, Naoki Hiroyoshi, John L. Provis, Tsutomu Sato
Separation and Purification Technology, 324, 124530, 124530, Elsevier BV, 2023年11月
研究論文（学術雑誌）

N-methyldiethanolamine (MDEA) as an effective CO2 absorbent for direct air capture (DAC) in cement-based materials
Kirushnapillai Kopitha, Yogarajah Elakneswaran, Ryoma Kitagaki, Ryosuke Saito, Masato Tsujino, Akira Nishida, Hisanori Senboku, Naoki Hiroyoshi
Chemical Engineering Journal, 475, 146067, 146067, Elsevier BV, 2023年11月
研究論文（学術雑誌）

Fluid-fluid interfacial properties during low salinity waterflooding
Yongqiang Chen, Javad Shokri, Vahid Niasar, Mohamed Mehana, Colin D. Wood, Yogarajah Elakneswaran, Juju Zhao
Journal of Molecular Liquids, 390, 123142, 123142, Elsevier BV, 2023年11月
研究論文（学術雑誌）

Proposing a Finite Element-based Multi-stage Model to Predict the Mechanical Properties of Cement Paste
NanoWorld Journal, 9, United Scientific Group, 2023年09月22日
研究論文（学術雑誌）

Role of pH and cations on emulsion formation and stability of crude oils
Xingjuan Hao, Yogarajah Elakneswaran, Sadia Afrin, Mai Shimokawara, Yoshitake Kato, Ryuta Kitamura, Naoki Hiroyoshi
Geoenergy Science and Engineering, 227, 211905, 211905, Elsevier BV, 2023年08月
研究論文（学術雑誌）

A Pretreatment of Refractory Gold Ores Containing Sulfide Minerals to Improve Gold Leaching by Ammonium Thiosulfate: A Model Experiment Using Gold Powder and Arsenic-Bearing Sulfide Minerals
Takunda Joseph Mhandu, Ilhwan Park, Sanghee Jeon, Sohta Hamatsu, Yogarajah Elakneswaran, Mayumi Ito, Naoki Hiroyoshi
Metals, 13, 8, 1357, 1357, MDPI AG, 2023年07月28日
研究論文（学術雑誌）, The use of thiosulfate to extract gold from refractory ores is promising because of its non-toxicity and high selectivity. Sulfide minerals (i.e., pyrite, arsenopyrite, chalcopyrite), major gold carriers in refractory gold ores, however, hinder gold extraction due to the high consumption of a lixiviant. In this study, a new method to improve gold extraction from sulfide bearing gold ores is proposed based on the model experiments using a mixture of gold powder and arsenopyrite-bearing sulfide (HAsBS) ore. The effects of HAsBS ore on gold leaching in ammonium thiosulfate solutions were investigated, and it was found that gold extraction in the presence of HAsBS ore was suppressed because of the unwanted decomposition of thiosulfate on the surface of sulfide minerals. To improve gold extraction in the presence of the sulfide minerals, this study investigated the effects of the pretreatment of HAsBS ore using ammonium solutions containing cupric ions and confirmed that HAsBS ore was oxidized in the pretreatment and its surface was covered by the oxidation products. As a result, thiosulfate consumption was minimized in the subsequent gold leaching step using ammonium thiosulfate, resulting in an improvement in gold extraction from 10% to 79%.

Selective Cementation of Gold Using an Iron Oxide and Zero-Valent Aluminum Galvanic System from Gold–Copper Ammoniacal Thiosulfate Solutions
Joshua Zoleta, Sanghee Jeon, Akuru Kuze, Nako Okada, Ilhwan Park, Mayumi Ito, Yogarajah Elakneswaran, Naoki Hiroyoshi
Metals, 13, 7, 1289, 1289, MDPI AG, 2023年07月18日
研究論文（学術雑誌）, Ammonium thiosulfate leaching is a promising alternative to the conventional cyanide method for extracting gold from ores. However, strategies for recovering gold from the leachate are less commercially used due to its low affinity to gold. The present study investigated the recovery of gold from the leachate using iron oxides (hematite, Fe2O3 or magnetite, Fe3O4). Cementation experiments were conducted by mixing 0.15 g of aluminum powder as an electron donor and 0.15 g of an electron mediator (activated carbon, hematite, or magnetite) in 10 mL of ammonium thiosulfate leachate containing 100 mg/L gold ions and 10 mM cupric ions for 24 h at 25 °C. The results of the solution analysis showed that when activated carbon (AC) was used, the gold was recovered together with copper (recoveries were 99.99% for gold and copper). However, selective gold recovery was observed when iron oxides were used, where the gold and copper recoveries were 89.7% and 21% for hematite and 85.9% and 15.4% for magnetite, respectively. An electrochemical experiment was also conducted to determine the galvanic interaction between the electron donor and electron mediator in a conventional electrochemical setup (hematite/magnetite–Al as the working electrode, Pt as the counter electrode, Ag/AgCl as the reference electrode) in a gold–thiosulfate medium. Cyclic voltammetry showed a gold reduction “shoulder-like” peak at −1.0 V using hematite/Al and magnetite/Al electrodes. Chronoamperometry was conducted and operated at a constant voltage (−1.0 V) determined during cyclic voltammetry and further analyzed using SEM-EDX. The results of the SEM-EDX analysis for the cementation products and electrochemical experiments confirmed that the gold was selectively deposited on the iron oxide surface as an electron mediator.

Zonal Isolation Material for Low-Temperature Shallow-Depth Application: Evaluation of Early Properties Development
Madhan Nur Agista, Mahmoud Khalifeh, Arild Saasen, Elakneswaran Yogarajah
SPE Journal, 1, 13, Society of Petroleum Engineers (SPE), 2023年07月01日
研究論文（学術雑誌）, Summary

Shallow-depth cementing presents unique challenges due to its low temperature and low pore pressure characteristic. The curing process of the cementitious material is typically prolonged at low temperatures resulting in a delayed curing process. The use of a low-density slurry to mitigate low pore pressure introduces another challenge, as it leads to a reduction in the final compressive strength. On the other hand, the operation requires the material to develop enough strength swiftly to be able to efficiently continue the next drilling operation. In addition, the presence of flow zones such as shallow gas and shallow water flow increases the complexity of the cementing process. There have been many developments in cementitious materials for shallow-depth cementing such as rapid-hardening cement and gas tight cement. However, there is little research focusing on the performance evaluation of each material at low-temperature conditions. This paper aims to present a thorough material evaluation for low-temperature shallow-depth cementing. The incorporated materials are American Petroleum Institute (API) Class G cement, rapid-hardening cement, gas tight cement, and geopolymer. Geopolymer is included to evaluate its potential as the green alternative to Portland-based cement. The sets of characterization were conducted during the liquid, gel, and solid phases. The samples were prepared under wide-ranging low temperatures and typical bottomhole pressures for shallow sections. The result shows different performances of each material and its behavior under low temperatures such as prolonged strength development and low reactivity, which necessitates further development of these materials.

A systematic review and assessment of concrete strength prediction models
Mylvaganam Nithurshan, Yogarajah Elakneswaran
Case Studies in Construction Materials, 18, e01830, e01830, Elsevier BV, 2023年07月
研究論文（学術雑誌）

Network Degradation Assessed by Evolved Gas Analysis–Mass Spectrometry Combined with Principal Component Analysis (EGA–MS–PCA): A Case of Thermo-Oxidized Epoxy/Amine Network
Takato Ishida, Ryoma Kitagaki, Yogarajah Elakneswaran, Junji Mizukado, Hideyuki Shinzawa, Hiroaki Sato, Hideaki Hagihara, Ryota Watanabe
Macromolecules, 56, 3, 883, 891, 2023年01月18日
英語, 研究論文（学術雑誌）

Numerical Simulation of Chloride Ion Ingression in Mortar Incorporating the Effect of ITZ Using an Integrated COMSOL-IPHREEQC Framework
Siventhirarajah Krishnya, Yogarajah Elakneswaran, Yuya Yoda, Ryoma Kitagaki
RILEM Bookseries, 43, 686, 696, 2023年
論文集(書籍)内論文

Effect of Carbonation on Microstructure of Cement Pastes with Different Water-to-Cement Ratios
K. Kopitha, S. Krishnya, Y. Elakneswaran, R. Kitagaki, Y. Yoda, M. Tsujino, A. Nishida
Lecture Notes in Civil Engineering, 362 LNCE, 149, 159, 2023年
研究論文（国際会議プロシーディングス）

Investigating the hydration characteristics of a new composite cementitious binder containing of slag and calcite
Chuang Li, Siventhirarajah Krishnya, Masataka Ogino, Eiji Owaki, Yogarajah Elakneswaran
Construction and Building Materials, 361, 129629, 129629, Elsevier BV, 2022年12月
研究論文（学術雑誌）

Coupling of a Reservoir Simulator with Geochemistry for Chemical Enhanced Oil Recovery
Angelo Kennedy Lino Limaluka, Yogarajah Elakneswaran
Day 4 Thu, November 03, 2022, SPE, 2022年10月31日
研究論文（国際会議プロシーディングス）, Abstract

Chemical enhanced oil recovery (CEOR) techniques are some of the most effective and economical tertiary oil extraction processes. As a key tool for the recovery performance evaluation, reservoir simulation plays an instrumental role in the expansion of the field application of CEOR. However, their framework models essentially the physical aspect of the recovery process. The significant influence of geochemical interactions on the recovery performance remains largely unintegrated. In this study, MATLAB Reservoir Simulation Toolbox (MRST) was coupled with PHREEQC for improved modeling and simulation of polymer flooding and low salinity water flooding (LSWF). The MRST’s polymer model was extended for multi-phase chemical transport by the addition of chemical species in wells boundary conditions, and phase relative permeabilities were modified to account for the wettability alteration effect of the flooding process. In validation, the coupled model showed a good match against PHREEQC in a simulation of a single-phase carbonate core low salinity water flooding (LSWF). It also validated well in the case of matching high salinity experimental results. A demonstrative application of the coupled model in the simulation of LSWF showed 27% maximum incremental oil recovery with a 3.3 mean water-oil ratio (WOR). Furthermore, combining LSWF with polymer flooding achieved the same recovery potential but with much lower water production (0.2 WOR) and doubled production period. These results preliminarily indicate that polymer flooding and LSWF could be combined for at least 27% additional original oil in place (OOIP) recovery with no more than 1 WOR in carbonate reservoirs. However, as this recovery performance evaluation was done in 1D, further work on the coupled model includes improving it for multi-dimensional application.

Retention mechanism of cesium in chabazite embedded into metakaolin-based alkali activated materials
Raudhatul Islam Chaerun, Natatsawas Soonthornwiphat, Kanako Toda, Kazuma Kuroda, Xiaobo Niu, Ryosuke Kikuchi, Tsubasa Otake, Yogarajah Elakneswaran, John L. Provis, Tsutomu Sato
Journal of Hazardous Materials, 440, 129732, 129732, Elsevier BV, 2022年10月
研究論文（学術雑誌）

In-situ infrared cure monitoring combined with two-trace two-dimensional (2T2D) correlation analysis to elucidate the matrix–filler interaction of nanocomposites: Case of thermosetting urethane/silica nanospheres
Takato Ishida, Ryota Watanabe, Hideyuki Shinzawa, Junji Mizukado, Hideaki Hagihara, Ryoma Kitagaki, Yogarajah Elakneswaran
Polymer Testing, 112, 107587, 107587, 2022年08月
英語, 研究論文（学術雑誌）

Adsorption behaviour of simulant radionuclide cations and anions in metakaolin-based geopolymer
Xiaobo Niu, Yogarajah Elakneswaran, Chaerun Raudhatul Islam, John L. Provis, Tsutomu Sato
Journal of Hazardous Materials, 429, 128373, 128373, Elsevier BV, 2022年05月
研究論文（学術雑誌）

Evaluating the Effect of Carbonate Impurities on Wettability Alteration Using a Geochemical Model
Xingjuan Hao, Moataz Abu-Al-Saud, Subhash Ayirala, Yogarajah Elakneswaran
Day 3 Wed, April 27, 2022, SPE, 2022年04月18日
研究論文（国際会議プロシーディングス）, Abstract

Wettability alteration considered as the principal mechanism has attracted more attention for low salinity waterflooding effect. It was significantly affected by electrokinetic interactions, which occurred at the interfaces of rock/brine and crude oil/brine. The mineral impurities of natural carbonate releasing ions have an important impact on the electrokinetics, which could lead to wettability shift subsequently. In this study, the effect of dolomite and anhydrite as the main impurities in natural carbonate, which caused wettability alteration, was evaluated using triple-layer surface complexation and thermodynamic equilibrium models coupled with extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The electrokinetics of crude oil and carbonate in brines were predicted by the triple-layer surface complexation model (TLM) based on zeta potential, while thermodynamic equilibrium model was mainly used for analyzing the carbonate impurities on wettability alteration. The equilibrium constants of reactions were determined by successfully fitting the calculated zeta potentials with measured ones for crude oil and carbonate in different solutions, which were validated for zeta potential prediction in smartwater. The disjoining pressure results show that there is a repulsion between crude oil and carbonate in Na2SO4 brine (Brine3) or smartwater (Brine4) equilibrating with calcite when comparing to that in MgCl2 (Brine1) and CaCl2 (Brine2), indicating the water-wet condition caused by the presence of sulphate ions. Moreover, the equilibrium of carbonate impurities with smartwater increases the repulsion between oil and carbonate. When the sulphate ion concentration in the adjusted smartwater exceeds a certain value, the effect of carbonate impurities on wettability alteration is not significant. Finally, the influence of smartwater pH on the interaction between oil and carbonate was evaluated with or without considering the equilibrium of carbonate impurities.

Modelling the Impact of Surface Charge on Wettability Alteration in Low Salinity Waterflooding
Yogarajah Elakneswaran
Day 2 Tue, April 26, 2022, SPE, 2022年04月18日
研究論文（国際会議プロシーディングス）, Abstract

The wettability alteration is the most prominent mechanism for a favorable effect of low salinity water flooding in enhanced oil recovery. It has been accepted that the surface charge at crude oil/brine and rock/brine interfaces significantly influences the interaction of the crude oil with rock surface and thus wettability changes. In this study, the interface characteristics were coupled with a solute transport model to simulate low salinity waterflooding in carbonate and sandstone reservoirs. The ionic transport and two- phase flow of oil and water equations were solved and coupled with IPhreeqc for geochemical calculations. The dissolution and precipitation of minerals were considered thorough thermodynamic equilibrium reactions in IPhreeqc. In addition, a triple layer surface complexation model was employed in IPhreeqc to predict electrokinetic properties of crude oil/brine and rock/brine interfaces. The wettability alteration was calculated based the adsorbed polar components of crude oil on minerals’ surface, which changes the relative permeability. The coupled model able to predict the spatiotemporal variation of ionic profiles, surface and zeta potentials, dissolution and precipitation of minerals, total disjoining pressure, and wettability index in addition to oil recovery for the injection of brines. The validity of the coupled model results was tested against PHREEQC in a single-phase flow without the presence of oil. Moreover, the modelling results were compared with the published experimental data for a single-phase flow in carbonate cores. A very good agreement between experimental data and modelling results was obtained. Furthermore, the coupled model was applied to predict ionic concentration, pH profile, and oil recovery in both carbonate and sandstone cores and verified with experimental data. The modelling results reproduce well the experimental data, suggesting that model captures the geochemical and interface reactions. Finally, the coupled model can be used to optimize brine composition for improved oil recovery in carbonate and sandstone reservoirs.

Delayed Absorption Superabsorbent Polymer for Strength Development in Concrete
Yuka Morinaga, Yuya Akao, Daisuke Fukuda, Yogarajah Elakneswaran
Materials, 15, 8, 2727, 2727, MDPI AG, 2022年04月07日
研究論文（学術雑誌）

Thermal aging of acrylic-urethane network: Kinetic modeling and end-of-life criteria combined with mechanical properties
Takato Ishida, Emmanuel Richaud, Matthieu Gervais, Alain Gaudy, Ryoma Kitagaki, Hideaki Hagihara, Yogarajah Elakneswaran
Progress in Organic Coatings, 163, 106654, 106654, 2022年02月
英語, 研究論文（学術雑誌）

Modeling of hydration products and strength development for high-volume fly ash binders
Siventhirarajah Krishnya, Charith Herath, Yogarajah Elakneswaran, Chamila Gunasekara, David W. Law, Sujeeva Setunge
Construction and Building Materials, 320, 126228, 126228, Elsevier BV, 2022年02月
研究論文（学術雑誌）

Proposing a three-phase model for predicting the mechanical properties of mortar and concrete
Siventhirarajah Krishnya, Yogarajah Elakneswaran, Yuya Yoda
Materials Today Communications, 29, 102858, 102858, Elsevier BV, 2021年12月
研究論文（学術雑誌）

Influence of carbonate impurities on smartwater effect: Evaluation of wettability alteration process by geochemical simulation
Xingjuan Hao, Moataz Abu-Al-Saud, Subhash Ayirala, Yogarajah Elakneswaran
JOURNAL OF MOLECULAR LIQUIDS, 340, 2021年10月
英語, 研究論文（学術雑誌）

Electrostatic properties of C–S–H and C-A-S-H for predicting calcium and chloride adsorption
Satoshi Yoshida, Yogarajah Elakneswaran, Toyoharu Nawa
Cement and Concrete Composites, 121, 104109, 104109, 2021年08月
英語, 研究論文（学術雑誌）

Hydration of ferrite-rich Portland cement: Evaluation of Fe-hydrates and Fe uptake in calcium-silicate-hydrates
Natsumi Noguchi, Krishnya Siventhirarajah, Takashi Chabayashi, Hiroyoshi Kato, Toyoharu Nawa, Yogarajah Elakneswaran
CONSTRUCTION AND BUILDING MATERIALS, 288, 2021年06月
英語, 研究論文（学術雑誌）

Role of moisture in photo-ageing -macromolecular architecture evolution of acrylic-urethane network
Takato Ishida, Ryoma Kitagaki, Hideaki Hagihara, Yogarajah Elakneswaran
Polymer Testing, 96, 107123, 107123, 2021年04月
英語, 研究論文（学術雑誌）

Effect of Electrokinetics and Thermodynamic Equilibrium on Low-Salinity Water Flooding for Enhanced Oil Recovery in Sandstone Reservoirs
Yogarajah Elakneswaran, Amir Ubaidah, Miku Takeya, Mai Shimokawara, Hirofumi Okano
ACS OMEGA, 6, 5, 3727, 3735, 2021年02月
英語, 研究論文（学術雑誌）

Durability of Slag-Blended Cementitious Materials Interacts with High Concentration of Sodium Sulphate
Yogarajah Elakneswaran, Chuang Li, Tomohiro Kajio, Eiji Owaki, Masataka Ogino, Toyoharu Nawa
RILEM Bookseries, 32, 39, 48, Springer Science and Business Media B.V., 2021年
英語, 論文集(書籍)内論文

A two-stage model for the prediction of mechanical properties of cement paste
Siventhirarajah Krishnya, Yuya Yoda, Yogarajah Elakneswaran
CEMENT & CONCRETE COMPOSITES, 115, 2021年01月
英語, 研究論文（学術雑誌）

Durability of slag-blended cement due to U-phase instability in sulphate environment
Yogarajah Elakneswaran, Chuang Li, Tomohiro Kajio, Eiji Owaki, Masataka Ogino, Toyoharu Nawa
MATERIALS AND STRUCTURES, 53, 6, 2020年12月
英語, 研究論文（学術雑誌）

Detecting pH and Ca2+ increase during low salinity waterflooding in carbonate reservoirs: Implications for wettability alteration process
Yongqiang Chen, Amir Ubaidah, Yogarajah Elakneswaran, Vahid J. Niasar, Quan Xie
Journal of Molecular Liquids, 317, 114003, 114003, Elsevier BV, 2020年11月
研究論文（学術雑誌）

Intrinsic Differences on the Photodegradation Mechanisms between Pigmented and Non-Pigmented Coatings Determined by Multi-Scale Analysis
T. Ishida, R. Kitagaki, H. Hagihara, Y. Elakneswaran
XV International Conference on Durability of Building Materials and Components. eBook of Proceedings, CIMNE, 2020年10月, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Encapsulation of Sr-loaded titanate spent adsorbents in potassium aluminosilicate geopolymer
Natatsawas Soonthornwiphat, Yutaro Kobayashi, Kanako Toda, Kazuma Kuroda, Chaerun Raudhatul Islam, Tsubasa Otake, Yogarajah Elakneswaran, John L. Provis, Tsutomu Sato
JOURNAL OF NUCLEAR SCIENCE AND TECHNOLOGY, 57, 10, 1181, 1188, 2020年10月
英語, 研究論文（学術雑誌）

A study of molecular architectural dynamics of crosslinked urethane during photo-aging by two-dimensional infrared correlation spectroscopy
Takato Ishida, Ryoma Kitagaki, Ryota Watanabe, Hideaki Hagihara, Yogarajah Elakneswaran, Hideyuki Shinzawa
POLYMER DEGRADATION AND STABILITY, 179, 109242, 109242, 2020年09月
英語, 研究論文（学術雑誌）

Effects of a New Type of Shrinkage-Reducing Agent on Concrete Properties
Mari Masanaga, Tsuyoshi Hirata, Hirokatsu Kawakami, Yuka Morinaga, Toyoharu Nawa, Yogarajah Elakneswaran
MATERIALS, 13, 13, 3018, 3018, 2020年07月
英語, 研究論文（学術雑誌）

Crude oil/brine/rock interface in low salinity waterflooding: Experiments, triple-layer surface complexation model, and DLVO theory
Miku Takeya, Amir Ubaidah, Mai Shimokawara, Hirofumi Okano, Toyoharu Nawa, Yogarajah Elakneswaran
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING, 188, 106913, 106913, 2020年05月
英語, 研究論文（学術雑誌）

Integrated geochemical modelling of low salinity waterflooding for enhanced oil recovery in carbonate reservoir
Yogarajah Elakneswaran, Miku Takeya, Amir Ubaidah, Mai Shimokawara, Hirofumi Okano, Toyoharu Nawa
International Petroleum Technology Conference 2020, IPTC 2020, International Petroleum Technology Conference (IPTC), 2020年
英語, 研究論文（国際会議プロシーディングス）

Adsorption / desorption phenomenon of crude oil to rock surface in low salinity waterflooding
Mai Shimokawara, Miku Takeya, Chiaki Otomo, Yasuyuki Mino, Elakneswaran Yogarajah, Toyoharu Nawa
International Petroleum Technology Conference 2020, IPTC 2020, International Petroleum Technology Conference (IPTC), 2020年
英語, 研究論文（国際会議プロシーディングス）

Challenges in prediction of significant structural changes during photochemical "degelation" of acrylic-urethane network
Takato Ishida, Ryoma Kitagaki, Hideaki Hagihara, Yogarajah Elakneswaran
POLYMER, 186, 122035, 122035, 2020年01月
英語, 研究論文（学術雑誌）

Effect of Acid Number on the Electrokinetic Properties of Crude Oil during Low-Salinity Waterflooding
Miku Takeya, Mai Shimokawara, Yogarajah Elakneswaran, Hirofumi Okano, Toyoharu Nawa
ENERGY & FUELS, 33, 5, 4211, 4218, 2019年05月, ［査読有り］
英語, 研究論文（学術雑誌）

Characteristics of Ferrite-Rich Portland Cement: Comparison With Ordinary Portland Cement
Yogarajah Elakneswaran, Natsumi Noguchi, Kazuki Matumoto, Yuka Morinaga, Takashi Chabayashi, Hiroyoshi Kato, Toyoharu Nawa
FRONTIERS IN MATERIALS, 6, 97, 2019年05月, ［査読有り］
英語, 研究論文（学術雑誌）

The effect of seeding of synthesized C-S-H with different C/S on early hydration reaction of alite　　　　　　　　　　　　　　　
Yumetoki Abe, Yuka Morinaga, Toyoharu Nawa, Yogarajah Elakneswaran
Sustainable Construction Materials and Technologies, 2, International Committee of the SCMT conferences, 2019年
英語, 研究論文（国際会議プロシーディングス）

Influence of Carbonated Water-rock Interactions on Enhanced Oil Recovery in Carbonate Reservoirs: Experimental Investigation and Geochemical Modeling
Mai Shimokawara, Elakneswaran Yogarajah, Toyoharu Nawa, Satoru Takahashi
JOURNAL OF THE JAPAN PETROLEUM INSTITUTE, 62, 1, 19, 27, 2019年, ［査読有り］
英語, 研究論文（学術雑誌）

Predicting the electrokinetic properties of the crude oil/brine interface for enhanced oil recovery in low salinity water flooding
Miku Takeya, Mai Shimokawara, Yogarajah Elakneswaran, Toyoharu Nawa, Satoru Takahashi
FUEL, 235, 822, 831, 2019年01月, ［査読有り］
英語, 研究論文（学術雑誌）

Modelling Long-Term Durability Performance of Cementitious Materials under Sodium Sulphate Interaction
Yogarajah Elakneswaran, Eiji Owaki, Toyoharu Nawa
APPLIED SCIENCES-BASEL, 8, 12, 2597, 2018年12月, ［査読有り］
英語, 研究論文（学術雑誌）

Influence of portlandite on Pyrex glass dissolution and the formation of alkali‐silica chemical reaction products
エラクネス ヨガラジャ
Journal of the American Ceramic Society, 101, 10, 4549, 4559, 2018年10月, ［査読有り］
英語, 研究論文（学術雑誌）

Influence of Surface Electrical Properties of C-S-H on Chloride Binding in Slag-Blended Cementitious Materials
Elakneswaran Yogarajah, Toyoharu Nawa, Kiyofumi Kurumisawa
JOURNAL OF MATERIALS IN CIVIL ENGINEERING, 30, 5, 1, 2018年05月, ［査読有り］
英語, 研究論文（学術雑誌）

Impact of portlandite on alkali-silica reaction of pyrex glass and blastfurnace slag aggregate
N. Noguchi, T. Kajio, Y. Morinaga, Y. Elakneswaran, T. Nawa, T. Ayan
6th International Conference on Durability of Concrete Structures, ICDCS 2018, 267, 272, 2018年
研究論文（国際会議プロシーディングス）

The Impact of Tortuosity on Chloride Ion Diffusion in Slag-Blended Cementitious Materials
Akira Hatanaka, Yogarajah Elakneswaran, Kiyofumi Kurumisawa, Toyoharu Nawa
JOURNAL OF ADVANCED CONCRETE TECHNOLOGY, 15, 8, 426, 439, 2017年08月
英語, 研究論文（学術雑誌）

Carbon dioxide saturated water injection for EOR in carbonate reservoir
Mai Shimokawara, Elakneswaran Yogarajah, Toyoharu Nawa, Satoru Takahashi
Society of Petroleum Engineers - SPE Abu Dhabi International Petroleum Exhibition and Conference 2017, 2017-, Society of Petroleum Engineers, 2017年
英語, 研究論文（国際会議プロシーディングス）

THE ROLE OF PORTLANDITE ON THE HYDRATION OF C₃A
Tomohiro KAJIO, Yuka MORINAGA, Yogarajah ELAKNESWARAN, Toyoharu NAWA
Cement Science and Concrete Technology, 71, 1, 40, 47, Japan Cement Association, 2017年
研究論文（学術雑誌）

Hydration study of slag-blended cement based on thermodynamic considerations
Yogarajah Elakneswaran, Eiji Owaki, Shigeyoshi Miyahara, Masataka Ogino, Tsuyoshi Maruya, Toyoharu Nawa
CONSTRUCTION AND BUILDING MATERIALS, 124, 615, 625, 2016年10月, ［査読有り］
英語, 研究論文（学術雑誌）

Chemical degradation of cementitious materials in various sulfate environments: Experimental results and model prediction
Y. Elakneswaran, T. Ishida
Life-Cycle of Structural Systems: Design, Assessment, Maintenance and Management - Proceedings of the 4th International Symposium on Life-Cycle Civil Engineering, IALCCE 2014, 1655, 1662, 2015年
研究論文（国際会議プロシーディングス）

Development and Verification of an Integrated Physicochemical and Geochemical Modelling Framework for Performance Assessment of Cement-Based Materials
Yogarajah Elakneswaran, Tetsuya Ishida
JOURNAL OF ADVANCED CONCRETE TECHNOLOGY, 12, 4, 111, 126, 2014年04月
英語, 研究論文（学術雑誌）

Durability of cementitious materials under combined sulphate attack and leaching: Development and application of a coupled physicochemical and geochemical model
Yogarajah Elakneswaran, Tetsuya Ishida
Sustainable Construction Materials and Technologies, 2013-August, 2013年
研究論文（国際会議プロシーディングス）

Multi-ion transport model in cement materials considering surface charge of hydrates　　　　　　　　　　　　　　　
T. Nawa, T. Goda, Y. Elakneswaran
Proceedings of the 3rd International Conference on the Durability of Concrete Structures, ICDCS 2012, Hokkaido University Press, 2012年
英語, 研究論文（国際会議プロシーディングス）

合成C-S-HにおけるSiOH基密度の推定
岩浅 瑛大, 合田 義, 名和 豊春, ELAKNESWARAN Yogarajah
セメント・コンクリート論文集, 65, 1, 54, 60, Japan Cement Association, 2011年
日本語, 塩化物イオン拡散メカニズムの解明は構造物の耐久設計に重要である。塩化物イオンの拡散過程において、特にC-S-H表面への物理吸着の影響が支配的であるとされているが、C-S-H表面における電気的性質について明らかにされていない。そこで本研究では、C-S-H表面における反応基であるSiOH基の表面錯体反応を考え、SiOH基密度や表面錯体反応の平衡定数の算出を目的とした。算出においては表面錯体モデルを用い、SiOH基の電離やカルシウムの吸着をモデル化し、塩基滴定実験やカルシウム吸着実験の実験結果と照合することにより、Ca/Siの異なる合成C-S-Hの表面電荷密度および平衡定数の算出を行った。その結果、SiOH基密度と平衡定数がC-S-HのCa/Siに依存することが明らかとなった。

Ion-cement hydrate interactions govern multi-ionic transport model for cementitious materials
ELAKNESWARAN Y, IWASA A, NAWA T, SATO T, KURUMISAWA K
Cement and Concrete Research, 40, 12, 1756, 1765, Elsevier, 2010年
英語, The main objective of this investigation is to describe the interaction between cement hydrates and electrolyte solution to understand multi-ionic transport in cementitious materials. A surface complexation model in PHREEQC including an electrostatic term is used to simulate the ionic adsorption on the calcium silicate hydrate (C-S-H) surface. The equilibrium constants for the adsorption of ions on C-S-H surfaces are obtained by fitting experimental data to the model. The adsorption of both divalent and mono-valent cations, and also anions significantly changes the surface charges of hydrated paste. Chloride is being held in a chemical binding as Friedel's salt and bound mainly by the adsorptive action of C-S-H. An integrated modelling approach employing a phase-equilibrium model, a surface complexation model, and a multi-component diffusion model has been developed in PHREEQC to simulate the multi-ionic transport through hydrated cement paste. It was found that the physical adsorption of ions on C-S-H, the size of pores, and the surface site density of C-S-H govern the rate of penetration of ionic species. Finally, the proposed model has been validated against chloride profiles measured in this study as well as with data available in the literature for hydrated cement paste.

Electrokinetic potential of hydrated cement in relation to adsorption of chlorides
Y. Elakneswaran, T. Nawa, K. Kurumisawa
CEMENT AND CONCRETE RESEARCH, 39, 4, 340, 344, 2009年04月
英語, 研究論文（学術雑誌）

Zeta potential study of paste blends with slag
Y. Elakneswaran, T. Nawa, K. Kurumisawa
CEMENT & CONCRETE COMPOSITES, 31, 1, 72, 76, 2009年01月
英語, 研究論文（学術雑誌）

INFLUENCE OF ELECTROLYTES ON SURFACE CHARGE DENSITY OF PASTES
ELAKNESWARAN Yogarajah, NAWA Toyoharu, KURUMISAWA Kiyofumi, HAYASHI Ami
セメント・コンクリート論文集, 61, 108, 114, 2008年02月20日
英語

Effect of GGBS on Membrane Potential of Pastes　　　　　　　　　　　　　　　
Y. Elakneswaran, T. Nawa, K. Kurumisawa, K. Fushimi
RILEM Proceedings PRO 46, Concrete Durability and Service Life Planning (ConcreateLife’06), 405, 414, 2006年, ［査読有り］
英語, 研究論文（国際会議プロシーディングス）

Surface Charge of Hardened Cement Paste Determined by Membrane Potential　　　　　　　　　　　　　　　
Yogarajah Elakneswaran, Toyoharu Nawa, Kiyofumi Kurumisawa, Koji Fushimi
Cement Science and Concrete Technology, 60, 111, 117, 2006年, ［査読有り］
英語, 研究論文（学術雑誌）

Exploring the Limit of Low-Salinity Waterflooding in a Carbonate Reservoir with Low Total Acid Number Oil
T. Uetani, M. Takeya, Y. Elakneswaran, APOGCE 2024, 14, 2024年10月11日
Abstract

This paper presents a workflow for designing the optimal injection brine composition for an offshore carbonate reservoir. The crude oil from this reservoir has a very low total acid number (0.01 mg KOH/g), leading to the expectation that injecting diluted seawater would not be an effective enhanced oil recovery (EOR) fluid. To address this, we designed a water composition that maximizes electrostatic repulsion (total disjoining pressure) at the oil-rock interface. This was achieved by combining two surface complexation models (oil-water and calcite-water interfaces), tuned to represent the reservoir conditions, with the extended DLVO theory. The total disjoining pressure was calculated for more than 30 different brine compositions, and we selected the one that demonstrated the highest value. The optimized injection brine, termed ‘repulsive’ water, was then evaluated in the laboratory for its oil recovery performance. Both spontaneous imbibition tests and coreflooding tests showed limited success with the repulsive water, yielding additional oil recovery factors of only 1-2%. We believe that the poor oil recovery results from insufficient repulsion at the oil-rock interface. Greater repulsion would be necessary for improved oil recovery, but this was not achieved within the scope of this study. Additionally, injecting diluted seawater (by fifty times) also failed to yield promising oil recovery results. Based on these findings, we conclude that low-salinity waterflooding is not a viable EOR option for the studied carbonate reservoir., SPE

DAC Coating Technology: Direct Air Capture and Corrosion Prevention in Concrete Structures
Keiichi Yano, Ryosuke Saito, Yuya Yoda, Masato Tsujino, Akira Nishida, Yogarajah Elakneswaran, Hisanori Senboku, Masatoshi Sakairi, Koji Fushimi, Ryoma Kitagaki, SSRN Electronic Journal, 2024年
Elsevier BV

エマルジョンとナノ粒子による高炉スラグ硬化体の初期強度・耐凍害性の改善
名和豊春, 胡桃澤清文, ELAKNESWARAN Y., 佐川孝広, 西祐宜, 環境助成研究成果 概要集 第38回・2017年度分:11件 第39回・2018年度分:23件 令和2年度, 2020年

汚染水処理から発生する使用済み合成ゼオライト及びチタン酸塩の長期保管における固化マトリックスとしてのジオポリマーの適用性
戸田賀奈子, SOONTHRONWIPHAT Natatsawas, TWO Hnin Wint Wint, 小林佑太朗, 黒田知眞, 森永祐加, 胡桃澤清文, YOGARAJAH Elakneswaran, 杉山隆文, KE Xinyuan, PROVIS John, 佐藤努, 日本原子力研究開発機構JAEA-Review(Web), 2018-017, 2018年

Physical, chemical, and mineralogical characteristics of blast furnace slag on durability of concrete
Elakneswaran Yogarajah, Toyoharu Nawa, Toshifumi Igarashi, THE THIRD INTERNATIONAL CONFERENCE ON SUSTAINABLE INFRASTRUCTURE AND BUILT ENVIRONMENT (SIBE 2017), 147, 2018年, ［査読有り］
英語

Ca(OH)₂溶液におけるモンモリロナイトの溶解速度—pHおよびC‐S‐H生成の影響—
木嶋達也, 中林亮, YOGARAJAH Elakneswaran, 小田治恵, 大竹翼, 佐藤努, 米田哲朗, 日本原子力学会秋の大会予稿集(CD−ROM), 2012, ROMBUNNO.B50, 622, 2012年09月03日
Ca(OH)2溶液におけるモンモリロナイトの溶解速度をフロースルー実験により算出した。溶解速度に対するpHの影響は先行研究で明らかにされているNaOH溶液におけるものと同様であった。一方、pHやCa濃度の条件によっては二次生成物としてC-S-Hが生成することが認められた。C-S-Hの生成がモンモリロナイトの溶解速度にどのような影響を与えるかを地球科学モデリングによって評価した。, 一般社団法人 日本原子力学会, 日本語

Prediction of ionic adsorption and multi–ionic transport in cementitious materials
エラクネスワラン ヨガラジャ, 名和 豊春, 佐藤 努, 胡桃澤 清文, Iwasa Akihito, 日本原子力学会 年会・大会予稿集, 2010, 0, 836, 836, 2010年
Cementitious materials are being used for encapsulation, back filling, and grouting purposes in deep geological repositories of long – lived radioactive waste. The long – term performance of cementitious materials has been investigating for safety disposal of radioactive waste. The durability performance of cementitious materials is mainly determined by resistance to transport of aggressive substances, however remain poorly understood. In this study, a thermodynamic integrated model has been developed to simulate multi-ionic transport in cementitious materials with considering ionic adsorption. The model has been validated against measured experimental data., 一般社団法人 日本原子力学会, 日本語

Influence of surface charge on ingress of chloride ion in hardened pastes
Y. Elakneswaran, T. Nawa, K. Kurumisawa, MATERIALS AND STRUCTURES, 42, 1, 83, 93, 2009年01月
英語

An integrated model to predict the relations between electrical double layer properties and chloride ingress in cement - Based materials
Y. Elakneswaran, T. Nawa, K. Kurumisawa, RILEM Workshop on Long-Term Performance of Cementitious Barriers and Reinforced Concrete in Nuclear Power Plants, NUCPERF 2009, 135, 142, 2009年01月01日

高炉スラグ微粉末混入ペーストの塩分浸透性と微細構造
胡桃澤清文, 名和豊春, ELAKNESWARAN Y., コンクリート技術シリーズ, 74, 2007年