Johnson dissolution models

ATK Lu, ME Frisella, KC Johnson. Dissolution modeling Factors affecting the dissolution rates of polydisperse powders. Pharm Res 10 1308-1314, 1993. 

The Johnson dissolution models described above postulate that h varies linearly with partide size up to a certain value, beyond which h remains unaltered. This assumption encompasses the differences in the release kinetics for both small and large particles. 

Potential cycling has been found to accelerate Pt dissolution compared with poten-tiostatic conditions. The dissolution mechanisms and dissolved species involved in this process are unclear [Johnson et al., 1970 Kinoshita et al., 1973 Ota et al., 1988 Rand and Woods, 1972]. Darling and Meyers have developed a mathematical model based on (9.5)-(9.7) to smdy Pt dissolution and movement in a PEMFC during potential cycling from 0.87 to 1.2 V [Darling and Meyers, 2003, 2005]. Severe Pt dissolution occurs when the potential switches to the upper limit potential (1.2 V), and then stops once a monolayer of PtO has formed. The charge difference between the anodic and cathodic cycles was found to be consistent with the amount... 

Johnson and Swindell [77] developed a method for evaluating the complete particle distribution and its effect on dissolution. This method divided the distribution into discrete, noncontinuous partitions, from which Johnson and Swindell determined the dissolution of each partition under sink conditions. The dissolution results from each partition value were then summed to give the total dissolution. Oh et al. [82] and Crison and Amidon [83] performed similar calculations using an expression for non-sink conditions based on a macroscopic mass balance model for predicting oral absorption. The dissolution results from this approach could then be tied to the mass balance of the solution phase to predict oral absorption. 

Anderson, M. R., Johnson, R. L., and Pankow, J. F., 1992, Dissolution of Dense Chlorinated Solvents into Groundwater. Modeling Contaminant Plumes Form Fingers and Pools of Solvent Environmental Science and Technology, Vol. 26, No. 5, pp. 901-907. 

Johnson KC (2003) Dissolution and absorption modeling Model expansion to simulate the effect of precipitation, water absorption, longitudinally changing intestinal permeability, and controlled release on drug absorption. Drug Dev. Ind. Pharm. 29 833-842. 

Anderson MR, Johnson RL,PankowJF (1992) Dissolution of dense chlorinated solvents into groundwater. 3. Modeling contaminant plumes from fingers and pools of solvent. Environ Sci Technol 26 901-908... 

Johnson T. M. and DePaolo D. J. (1997a) Rapid exchange effects on isotope ratios in groundwater systems 1. Development of a transport—dissolution—exchange model. Water Resour. Res. 33, 187—195. 

Johnson KC. Dissolution and Absorption Modeling Model Expansion to Simulate the Effects of Precipitation, Water Absorption, Longitudinally Changing Intestinal Permeability, and Controlled Release on Drug Absorption. Drug Devloplnd Pharm 2003 29 833-842. 

Spent fuel. Although several major assessments of spent fuel disposal concepts have been carried out (e.g. Anttila et al. 1982 KBS 1983 SKB 1992 Vieno et al. 1992), Nagra have carried out only preliminary assessments to date (Nagra 1985 Schneider et al. 1997). Other than the potential scenarios already discussed above for other components of the EBS which may have an impact on the spent fuel (e.g. redox front propagation through the bentonite buffer), the most significant potential perturbation identified so far relates to radiolytically induced dissolution of the fuel matrix (Forsyth 1995). Despite an extensive laboratory based data-set (e.g. Forsyth Werme 1987, 1992 Bruno et al. 1995 Loida et al. 1995), the fact that much of the data have been produced using only model solutions means that uncertainties remain in the likely rate of radiolysis under near-field conditions (Johnson et al. 1994). 

Johnson and Pankow (1992) presented a simple analytical model for dissolution of pools of a NAPL by treating the mass transfer to be a vertical transport process. The general two-dimensional mass transport equation can be simplified by assuming ... 

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