Global ETD Search
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 35 for “"semi-batch"”.
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Gas holdup in a gas-liquid-fiber semi-batch bubble column
<p>A 4-m high, 15.24-cm diameter semi-batch bubble column connected to one of three perforated plate gas distributors with open area ratios A = 0.57%, 0.99%, and 2.14% is employed to study gas holdup and flow regime in Rayon and Nylon fiber suspensions. This study determines the effect of …
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Point of Use Semi-Batch Reverse Osmosis Desalination Prototype Experimental Validation
… was identified that recirculating brine within a semi-batch configuration with a brine flushing mechanism can potentially achieve 75% or higher recovery ratios. A prototype made from off-the-shelf parts was engineered by a group of graduate students associated with the Global Engineering and …
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Modeling and experimental validation of a single-feed semi-batch precipitation process
… conditions. In the present work, the single-feed semi-batch precipitation process of barium sulfate in a stirred tank was experimentally studied and numerically predicted using a micromixing model based on CFD. A commercial CFD package (FLUENT) was used to simulate the flow field and predict the …
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Dynamic Modelling and Optimization of Polymerization Processes in Batch and Semi-batch Reactors. Dynamic Modelling and Optimization of Bulk Polymerization of Styrene, Solution Polymerization of MMA and Emulsion Copolymerization of Styrene and MMA in Batch and Semi-batch Reactors using Control Vector Parameterization Techniques.
… emulsion copolymerization of Styrene and MMA in batch and semi-batch reactors are the focus of this work. In this work, models are presented as sets of differential-algebraic equations describing the process. Different optimization problems such as (a) maximum conversion (Xn), (b) maximum number …
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Experimental and kinetic modelling of multicomponent gas/liquid ozone reactions in aqueous phase. Experimental investigation and Matlab modelling of the ozone mass transfer and multicomponent chemical reactions in a well agitatated semi-batch gas/liquid reactor.
… in this study. Mass transfer parameters in the semi-batch reactor were determined using oxygen and ozone at different flow rates in the presence and absence of t-butanol. t-Butanol is used as a radical scavenger in ozonation studies and it has been found to affect the gas¿liquid mass transfer …
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Modelling and optimisation of batch distillation involving esterification and hydrolysis reaction systems. Modelling and optimisation of conventional and unconventional batch distillation process: Application to esterification of methanol and ethanol using acetic acid and hydrolysis of methyl lactate system.
Batch distillation with chemical reaction when takes place in the same unit is referred to as batch reactive distillation process. The combination reduces the capital and operating costs considerably. Among many different types of batch reactive distillation column configurations, (a) conventional …
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Processing and characterization of nanocrystalline ceria
… it difficult to sinter. In this dissertation, a semi-batch reactor method was developed for directly synthesizing undoped an doped, nanometer-scale CeO₂ particles at room temperature"--Abstract, page iv.
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Field investigation and simulation of nutrient control in a fish-hatchery wastewater stabilization pond system
… Three lab-scale tests were run; a short-term semi batch test to predict the maximum P removal using Langmuir’s isotherm, a long-term semi-batch test to quantify the total P removal, and a column flow-through test to better quantify the medium’s P removal as a lab-scale simulation of a field …
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Synthesis and Optimization of Emulsion Polymers
… polymerization processes were used including semi-batch, starved-feed, and in-situ seeded in the attempt to produce a stable latex that can be used in a broader study concerning the syneresis and rheology mechanisms of latex/thickener systems. In addition, this project investigates the …
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CFD Simulation of Chemical Looping Combustion System
… This dissertation focuses on designing a novel semi-batch CLC unit using fluidized-bed reactors and modeling the hydrodynamics of fluidized bed reactors with use of CFD. The National Energy Technology Laboratory's (NETL, USA) open-source code MFIX is used in this study as flow solver for CFD …
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Making Decentralized Desalination More Affordable Using Improved Process Design, Control, and Energy Recovery
… electrodialysis (ED) and reverse osmosis (RO). Batch ED desalination, which relies on recirculating water to reach a desired product concentration, is often conducted at constant voltage. This operation scheme causes the membrane area to be underutilized because the ratio of applied current to …
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Investigations of biphasic seeded emulsion polymerizations in a continuous tubular reactor
… approaches have mostly focused on transposing batch emulsion polymerization recipes into tubular reactors. While this transposition had been successful in producing low solids contents material, it failed at producing industrial-grade latex (>30 w%) due to the accumulation of solids (fouling) …
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Amine and Catalyst Stability Studies in the Catalyst-Aided CO2 Capture Process
… under typical absorption conditions in a semi -batch mode. The results revealed that CNTs/K-MgO increases solvent degradation. Degradation was direct ly proportional to temperature in the region of 313-333K. It was also found that the catalyst reduces the activat ion energy of degradation …
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Chemometric methods for the analysis of process spectra using minimal reference data
… must be obtained. For a dynamic system such as a batch or semi-batch chemical reaction, creating such a data set may be very difficult or extremely time consuming. It may not be possible to create synthetic mixtures because reaction between the various reactants may occur. If the reaction proceeds …
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Mathematical modeling, simulation, and optimal design of pharmaceutical crystallizers
… of crystals due to ultrasonication, 2) a semi-batch anti-solvent crystallization, and 3) continuous slug-flow crystallization, which are solved by three distinct simulation methods: 1) breakage matrix with integer arithmetic, 2) method of characteristics, 3) method of moments combined with …
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Kinetic analysis of thiol oxidation to study the effects of fluorinated groups on metal phthalocyanine catalysts
… in a reaction-limited, isothermal, bench-scale, semi-batch reactor, with thiol concentrations measured using GC/FID. Conversions of 2-ME to 2-hydroxyethyl disulfide and 4-FBT to 4-fl uorophenyl disulfide in excess of 90% are achieved. Kinetic analyses suggest that the substrate binding and …
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Degradation of Emerging Contaminants by Advanced Oxidation Using Multi-Walled Carbon Nanotubes and Continuous Ozone Injection
… However, these previous studies used a batch system with an initial aliquot of ozone, which would not be a feasible option in a commercial application. This research compares results from a semi-batch system with a continuous injection of ozone to these previous batch system studies to …
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Forsterite Dissolution Kinetics: Applications and Implications for Chemical Weathering
… oxalic acid solutions: based on a series of 124 semi-batch reactor experiments over a pH range of 0 to 7 and total oxalate concentrations between 0 and 0.35 m at 25°C. These experiments show that oxalate-promoted dissolution rates depend upon both oxalate concentration and pH. I propose a …
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Direct Precipitation of Micron-Size Salbutamol Sulphate by Antisolvent Crystallization
… of crystallized SS particles. A process study of semi-batch antisolvent crystallization was subsequently conducted. It has shown that the final size of the crystalline product was sensitive to the operating parameters such as feeding rate of antisolvent, stirring speed, and addition of PVP. …
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Leaching from High Capacity Arsenic-Bearing Solid Residuals under Landfill Conditions
… under anaerobic/reducing conditions. Under semi batch landfill simulation experiments, our results show that non iron based media leached arsenic above the Toxicity Characteristics limit (TC) and it was observed that sorbate (As) might leach at a faster rate than the sorbent itself. It is …
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