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 20 for “"Filtration efficiency"”.
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Use and performance of BioSand filters in Posoltega, Nicaragua
… with objectives of determining the long-term filtration efficiency and the rate of sustained use. Field methods included microbial and turbidity water quality testing and interviews with filter users regarding the operation, maintenance and perceptions towards the filters. Of the 234 BioSand …
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Presence and Stability of SARS-CoV-2 on Indoor Surfaces and Masks
… effectiveness of 11 face coverings for material filtration efficiency, inward protection efficiency on a manikin, and outward protection efficiency on a manikin. Masks made of filter materials, such as vacuum cleaner bag and HVAC filters, achieved a high material filtration efficiency whereas …
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Studies of modified pumice and titanomagnetite filtration media
There is a continuing interest in filtration technologies capable of more efficient filtration, particularly of small microbial particles, but which place less reliance on the use of water treatment chemicals. In order to develop new options for granular filtration systems, two indigenous New …
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Novel diesel particulate filters containing fine ceramic fibres
… improvements are being sought are in enhanced filtration efficiency of very fine particles (<50 nm), particularly immediately after regeneration (the periodic removal of accumulated particulate via combustion), and in improved thermal shock resistance. To contribute to these aims, this work …
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Fluidization and soot filtration in a rotating fluidized bed
… the nature of fluidization, particle mixing and filtration in the RFB. In an RFB, particles are subject to a centrifugal force which can be much larger than the force of gravity. Therefore the Geldart classification for conventional fluidized beds must be modified for rotating fluidized beds. A …
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Development and application of a channel-scale exhaust after-treatment model
… DPF is investigated using the model. The filtration model is extended based on experimentally observed non-uniform combustion of the soot cake layer and a reduction in filtration efficiency of the filter wall at high temperature. The extended model is shown to be able to better describe …
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Mathematical modeling of membrane filtration
… investigate new mathematical models for membrane filtration. The work presented is divided into six chapters. In the first chapter the problem is introduced and motivated. In the second chapter, a new mathematical model for flow and fouling in a pleated membrane filter is presented. Pleated …
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Process-Property Characterization for Multi-Material Jetting Applications
… production of respirators via AM, the lack of filtration efficiency testing generated concerns about the respirators' effectiveness. The goal of this work was to measure particle transmission through respirators fabricated with powder bed fusion and fused filament fabrication processes and …
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Chemical modification of activated carbon adsorbents
… effects. A study of the factors controlling the efficiency with which hydrophobic vapours; are adsorbed from humid air revealed that the surface chemistry of the carbon is important, but that under typical conditions of use, filter performance was limited by the rate at which water displaced by …
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Characterizing ash properties and effects on Diesel Particulate Filter flow resistance
… aftertreatment system is chosen for its high filtration efficiency and relative simplicity. The porous ceramic substrate captures the particulate matter which is comprised of combustible soot and inorganic metallic ash. While the soot can be cleared from the filter through high temperature …
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Ash impacts on gasoline particulate filter performance and service life
… Diesel particulate filters have a demonstrated filtration efficiency of 95% or greater and have reduced diesel particulate mass (PM) emissions by one to two orders of magnitude. GDI engines require no more than one order of magnitude reduction in particulate emissions to meet new regulations. …
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Aerodynamic Interactions in Vortex Tube Separator Arrays
… within associated separators that could affect filtration efficiency. The key factor here is the global swirl intensity, which is increased in array flows due to high angular momentum contributions from separators that are radially distant from the duct center. A preliminary momentum integral …
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The Control of Diesel Particulates in Underground Coal Mines
… a) The construction of a test rig to measure the efficiency and backpressure of new and used disposable filters b) The testing of the in service fleet at four of BHP Billiton Illawarra Coal mines using an R&P Series 5100 diesel analysis system mounted in a trailer c) Comparison of a newer design …
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Influence of Ag Nanoparticle Loading on Dye and Salt Removal Efficiency of Graphene Oxide Membranes
… Among these, graphene oxide (GO)-based nanofiltration membranes have emerged as promising candidates due to their high mechanical strength, tunable surface chemistry, and exceptional molecular sieving properties. However, despite these advantages, the practical deployment of GO membranes in …
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MRI Studies of Gas Hydrodynamics in Automotive Particulate Filters
… allowing calculation of the through-wall or filtration velocity. This provides data for comparison with 1D and 3D CFD models at a range of flow rates. The 3D CFD model is validated for modest Reynolds numbers and allowed parameters such as flow profile shape and wall friction to be explored. …
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Crystallization of calcium sulphate during phosphoric acid production : improving filtration through improvement in particle shape and size distribution
… are key factors in determining the downstream filtration efficiency. Particularly, the metal ion impurities coming from raw phosphate rock play an important role as shape modifiers. The presence of impurities in the acid mixture has an impact both thermodynamically and kinetically, although …
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Fibrous Membranes in Personal Protective Applications
… to harmful aerosol constituents by selective filtration. Filtration using the UFF membranes is shown to change both the size distribution and the chemical composition of a binary liquid aerosol when the selective particle size range of the membrane is aligned with the aerosol size …
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Evaluation of granular media to wastewater treatment; advanced primary treatment utilising modified pumice, titanomagnetite and ceramic nozzles.
… impact of human activity on the environment. Filtration of primary treated effluent (PTE) and secondary treated effluent (STE) offers a possible sustainable technology for meeting or partially meeting these demands. Granular media filtration, if used at all, is typically incorporated in …
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Developing a low-cost ceramic micro-porous water filter for removal of microorganisms that cause common diseases
… 7 m2 g-1 and a high flow rate which explains the filtration efficiency of the filter. The 32 minute retention time of water further helps with the filtration effectiveness. Bacteriological testing exceeded all expectations. The product was tested using water contaminated with high concentrations …
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Supramolecular Nanofibers - Preparation, Structure-Property Relations, and Applications
… as protective suits, and especially in air filtration as filter media. Generally, nanofibers are prepared by top-down approaches. However, these processes feature several disadvantages. As consequence cost-effective alternative strategies are required. One strategy to this problem is the …