A5026022410- Radioactive element chemistry and processing
- Chemical Synthesis and Characterization
- Nuclear and radioactivity studies
- Analytical chemistry methods development
- Graphite, nuclear technology, radiation studies
- Nuclear Materials and Properties
- Radioactive contamination and transfer
- Groundwater flow and contamination studies
- Concrete and Cement Materials Research
- Electrostatics and Colloid Interactions
- Lanthanide and Transition Metal Complexes
- Nuclear materials and radiation effects
- Extraction and Separation Processes
- Clay minerals and soil interactions
- Radioactivity and Radon Measurements
- Risk Perception and Management
- Nuclear reactor physics and engineering
- Minerals Flotation and Separation Techniques
- Laser-induced spectroscopy and plasma
- Iron oxide chemistry and applications
- Isotope Analysis in Ecology
- Magnesium Oxide Properties and Applications
- Soil and Unsaturated Flow
- Microfluidic and Bio-sensing Technologies
- Marine and coastal ecosystems
McMaster University
2014-2024
The University of Tokyo
2004-2022
Natural Sciences and Engineering Research Council
2019
Japan Atomic Energy Agency
2010
Saitama University
2001
Tokai University
1988
A Nuclear Power Plant (NPP) is a complex dynamic system-of-systems with highly nonlinear behaviors. In order to control the plant operation under both normal and abnormal conditions, different systems in NPPs (e.g., reactor core components, primary secondary coolant systems) are usually monitored continuously, resulting very large amounts of data. This situation makes it possible integrate relevant qualitative quantitative knowledge artificial intelligence techniques provide faster more...
The adsorption of natural organic matter (NOM) on mineral (hydr)oxide plays an important role in the evaluation speciation toxic metal ions environment. Because both NOM and oxide have variable charges that adjust upon adsorption, a good understanding proton binding is required before can be understood. In this study, purified Aldrich humic acid (PAHA) goethite was examined as function environmental conditions (pH, salt concentration, free concentration PAHA) together with to PAHA, goethite,...
A nuclear power plant (NPP) is a highly complex system-of-systems as manifested through its internal systems interdependence. The negative impact of such interdependence was demonstrated the 2011 Fukushima Daiichi disaster. As such, there critical need for new strategies to overcome limitations current risk assessment techniques (e.g. use static event and fault tree schemes), particularly simulation nonlinear dynamic feedback mechanisms between different NPP systems/components. first key...
Binding of heavy metal and actinide ions to natural colloids, such as humic substances (HSs) (hydr)-oxides, plays an important role in the ecotoxicological behavior these ions. Several thermodynamic models have been constructed predict speciation metal/HS or metal/oxide binary systems. However, environments adsorption HSs on oxides can influence binding target metals, leading deviation from additivity calibrated models. In this study copper (Cu2+) purified Aldrich acid (PAHA)/goethite...
Summary Sorption and desorption experiments of Np on magnetite hematite under aerobic anaerobic conditions were carried out to investigate the possibility reduction Np(V) Np(IV) at pH 4 8 within 7 days. The amount sorbed was about 2 or 3 times greater than that conditions. Furthermore, results indicated dominant sorption behavior quite different from oxidation state iron oxides determined by extraction technique using 0.5 M TTA in xylene 2.0 HNO solution solid phase after experiment. 90% 10%...
Time-resolved laser fluorescence spectroscopy (TRLFS) is an analytical technique capable of discriminating different chemical species a fluorescent metal ion such as UO22+, Cm3+, and lanthanides. Although TRLFS has been widely used to investigate the speciation ions, extracting quantitative structural information from multiple data measured function physical parameters not simple task. The purpose this study apply parallel factor analysis (PARAFAC) for interpretation series data. PARAFAC...
High pH conditions of aqueous solutions in a radioactive waste repository can be brought about by dissolution cementitious materials. In order to clarify the mechanisms involved maintaining this high for long time, we investigated phenomena OPC hydrate. present research, leaching tests on powdered cement hydrates were conducted changing ratio mass water hydrate (liquid/solid ratio) from 10∽2, 000 (wt/wt). Ordinary Portland Cement was contacted with deionized and placed sealed bottle. After...
Summary The sorption kinetics of neptunium on magnetite was investigated under both aerobic and anaerobic conditions in 0.1mol L -1 NaNO 3 at pH=5.7 to 5.9. It found that the reaches an equilibrium 1h conditions, while it takes 10h or more reach conditions. difference between took place because condition involved reduction Np(V) Np(IV), confirmed by extraction technique using 0.5mol TTA xylene 2.0mol HNO solution. rate Fe(II) calculated solution with magnetite. reduced 1000 times faster than...
Summary Humic acids are natural organic materials that play an important role in the migration of heavy metal and actinide ions aquatic soil systems. In present study, binding protons, copper uranyl to purified Aldrich humic acid (PAHA) is investigated results modeled with Non-Ideal Competitive Adsorption (NICA) model extended electrostatic interactions according Donnan (NICA-Donnan model). The NICA part enables one describe competitive ion a heterogeneous substrate taking into account...
In Part I, phase diagrams and energy entropy of change states vs. composition curves Pb-Cd Bi-Cd systems obtained from the specific heat measurements theory diagram proposed by Takagi Nagasaki were given. particular, positions eutectic points on above discussed.In II, together with results Sn-Bi system, fusion or solution alloys investigated synthetically. Two important phenomena discussed in this part are Bi atoms into Sn solid anomalous liquid metals alloys.In study former, quantity...
Raman spectra of uranyl ion−loaded silver and gold colloidal particles have been measured. The active symmetric stretching frequency ions shifts to a smaller wavenumber by the adsorption onto sols. shift is so large that it discounts case weak bonding between species both sols suggests extensive σ donation from surface equatorial plane adsorbed species. For sols, spectrum changes significantly upon varying pH suspensions corresponds different does not change thus only one notion involves...
Adsorption of randomly branched polyelectrolytes, "hairy" particles and internally structured macromolecules, collectively denoted as heterogeneously charged nanoparticles, on surfaces is important in many technological natural processes. In this paper, we will focus (1) the charge regulation both nanoparticle surface (2) complexation between particle functional groups sites theoretically study adsorption using extended approach. The model explicitly considers electrochemical potential a...
From the viewpoint of waste management, a quantitative evaluation LWR nuclear fuel cycle system performance was carried out, considering both higher burn-up operation UO2 coupled with introduction MOX fuel. A major parameter to quantify this is number high-level (HLW) glass units generated per GWd (gigawatt-day based on reactor thermal power generation before electrical conversion). This evaluated for each up maximum 70GWd/THM ton heavy metal) assuming current conventional reprocessing and...