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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"dissolution kinetics"”.
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Limestone dissolution kinetics in upflow reactor systems
… addresses the problem of modelling the kinetics of the dissolution process and calibrating the model by experimentation.
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Thorium oxide dissolution kinetics for hydroxide and carbonate complexation
… behavior of thorium oxide was investigated. The kinetics of crystalline thorium oxide dissolution were studied under argon and argon/10% CO2 over a broad pH range in 0.1 M ionic strength NaC1O4 solution. Samples were analyzed for thorium concentration using ICP-AES, ICP-MS, and NAA. Data was fit …
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Forsterite Dissolution Kinetics: Applications and Implications for Chemical Weathering
… important factors that affect silicate mineral dissolution rates and grain lifetimes in the weathering environment. I determined an empirical rate law for forsterite dissolution of forsterite in oxalic acid solutions: based on a series of 124 semi-batch reactor experiments over a pH range of 0 …
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The hydrated lime dissolution kinetics in acid mine drainage neutralization
… dissolved heavy metals mainly ferrous iron. The dissolution of Ca(OH)₂ in aqueous solution is complex, which make its kinetics in AMD neutralization difficult to understand. The aim of this study was therefore to understand the Ca(OH)₂ kinetics in simplified solutions such as de-ionized water and …
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Dissolution kinetics and mechanisms in quartz- and grainite-water systems
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1994.
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Dissolution kinetics of model api in molten polymer excipients during batch processing
… with minimal API degradation. Therefore, the kinetics of the dissolving process should be known. In this work, the expression of dissolution process and the impact of shear rate, API concentration and API species in dissolution kinetics are determined. The viscosities of the mixture at …
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Dispersion and dissolution kinetics of API particles in pharmaceutical hot melt extrusion
… pumping. However, for pharmaceutical HME, the dissolution of the API (Active Pharmaceutical Ingredient) is an additional and very important elementary step, along with the melting of the polymeric excipient that precedes it, and mixing which accelerates the dissolution process. A major concern …
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Cellulose-based amorphous solid dispersions enhance rifapentine delivery characteristics and dissolution kinetics in vitro
The efficacy of rifapentine, an oral antibiotic used in the treatment of tuberculosis, is reduced due to its degradation at gastric pH and low solubility at intestinal pH. We aimed to improve delivery properties in vitro by incorporating rifapentine into pH-responsive amorphous solid dispersions …
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Cellulose fiber dissolution in sodium hydroxide solution at low temperature: dissolution kinetics and solubility improvement
… understanding of the NaOH and NaOH/urea dissolution process significantly constrains its applications. In order to fully understand the cellulose dissolution in alkali system, there are several aspects of problems that need to be addressed. Our focus in this study is in the interaction of …
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Effects of the Desorption and Dissolution of Polycyclic Aromatic Hydrocarbons on Phytoremediation at a Creosote-Contaminated Site
… may be rate-limited by the desorption and dissolution kinetics of the PAH's on-site. The objectives of this research are to: (1) estimate the desorption and dissolution rates of 10 PAH's found in the subsurface and (2) estimate the amount of each PAH and total mass of contaminant that is …
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Development of Functional Polymeric Materials for Microfluidic Systems
… been demonstrated, and the factors that affect dissolution kinetics have been understood through systematic studies and mechanical modeling. In conclusion, the introduction of functional polymeric materials into microfluidics via direct photopolymerization has the potential to greatly simplify …
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NANOPARTICLE DEPOT FOR INTRAPERITONEAL CHEMOTHERAPY OF OVARIAN CANCER
… and temperature-induced crystallization. Dissolution kinetics of PNC could be determined by the light scattering method rather than the dialysis method due to drug reprecipitation caused by diffusion barrier. PTX release profiles from PNC-gel and PTX precipitate-gel (PPT-gel) were …
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HIGH TEMPERATURE KINETICS OF PRECIPITATION AND DISSOLUTION OF FERROUS-CARBONATE
… been studied extensively. The enthalpy of the dissolution reaction has been calculated to be $-22.8$ $\pm$ 0.6 kJ/mole, which is close to the NBS (1) reported value. The precipitation kinetics fit an empirical second order rate law with an activation energy of (9.31 $\pm$ 1.47) $\times$ …
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The kinetics of drug dissolution in polymers during hot-melt extrusion
… melt. Extrusion-generated mixing accelerates dissolution process. One issue concerning the pharmaceutical industry is the degradation of drugs when they are exposed to relatively high temperatures of the extrusion process (usually 100 C above ambient). In order to keep drugs from thermally …
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Controlled Evaluation of Silver Nanoparticle Dissolution Using Atomic Force Microscopy
… of their unintended release to the environment. Dissolution is an important environmental transformation that affects the form and concentration of AgNPs in natural waters; however, studies on AgNP dissolution kinetics are complicated by nanoparticle aggregation. Herein, nanosphere lithography …
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A modular atomic force microscope for nanotechnology research
… and stripping is observed. Second, calcite dissolution in low-pH environments is imaged. Dissolution processes in sulfuric and hydrochloric acid solutions are compared. It is apparent that the rhombohedral crystalline structure of the calcite clearly influences the dissolution kinetics in …
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The effect of composition on the viscosity, crystallization and dissolution of simple borate glasses and compositional design of borate based bioactive glasses
… <p>Similar glasses were used to study dissolution processes in water. These alkali-alkaline earth glasses dissolve congruently and follow linear dissolution kinetics. The dissolution rates were dependent on the glass structure, with slower rates associated with greater fractions of …
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DEVELOPMENT AND APPLICATION OF ENSEMBLE MACHINE LEARNING ALGORITHMS TO ENABLE A PRIORI, HIGH-FIDELITY, AND PROMPT PREDICTIONS AND OPTIMIZATIONS OF COMPLEX MATERIALS AND SYSTEMS
… models are employed to predict and optimize the dissolution kinetics of bioactive glasses. The sixth study compares the performance of analytical and ML models in predicting the sulfur solubility of nuclear waste glasses. In some aforesaid studies, closed-form analytical models are developed to …
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The dissolution rate of chrysotile
… in lung tissue is simply a result of its dissolution kinetics. The purpose of this study was to estimate the lifetime of a respirable size fiber of chrysotile in lung tissue. The dissolution reaction for chrysotile for pH's less than nine is: Mg₃Si₂O₅(OH)₄ + 6H⁺ = 3Mg²⁺+ 2H₄4SiO₄ + H₂0 …
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Assessment of the potential carbon footprint of engineered processes for the mineral carbonation of PGM tailings
… Many of the strategies proposed to enhance the dissolution kinetics of silicate minerals, such as the use of elevated temperatures and pressures and chemical additives, as well as pretreatment through mechanical and thermal activation, are energy intensive and will thus reduce the net CO2 …
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