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Annapoorneswari, Rajasekharan Pillai. "Fine particle classification using dilute fluidized beds." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Anna_thesis_final_09007dcc8036723f_09007dcc804465a7.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 11, 2007) Includes bibliographical references (p. 50-51).
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Silva, Carlos Alexandre Moreira da 1984. "Aplicação de tecnologias analíticas de processo e inteligência artificial para monitoramento e controle de processo de recobrimento de partículas em leito fluidizado." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266036.
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Orientador: Osvaldir Pereira TarantoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: As indústrias química, alimentícia e farmacêutica têm empregado extensivamente a operação de fluidização em inúmeros processos, devido às suas características bastante atrativas, que possibilitam um contato efetivo entre a fase sólida e fluida, o que reflete na geração de altas taxas de transferência de calor e de massa. No entanto, o regime de fluidização borbulhante, o qual é condição de partida dos processos que envolvem esta operação, frequentemente é afetado pelas condições operacionais. As temperaturas elevadas, o conteúdo de umidade excessivo das partículas e a introdução de líquidos no leito fluidizado podem conduzir a instabilidades no regime fluidodinâmico e provocar o colapso parcial ou total do leito, reduzindo a eficiência do processo. A manutenção de condições estáveis do regime de fluidização durante processos de recobrimento de partículas em leitos fluidizados é de fundamental importância para garantir uma eficiência de recobrimento favorável e evitar a formação de zonas sem movimentação e aglomeração das partículas no leito, pois estes fatores indesejáveis comprometem a mistura entre as fases e conseqüentemente a qualidade do produto final. Dentro deste contexto, a utilização de um sistema de monitoramento e controle em tempo real de processos de recobrimento de partículas é extremamente desejável para permitir a operação de regimes de fluidização estáveis e garantir um filme de recobrimento uniforme e boas condições de escoabilidade dos sólidos. A presente proposta de tese de doutorado tem por objetivo aplicar a metodologia de análise espectral Gaussiana dos sinais de flutuação de pressão (Parise et al. (2008)), para o desenvolvimento de sistemas de controle baseados em inteligência artificial (Lógica Fuzzy), visando monitorar a estabilidade do regime de fluidização em processo de recobrimento de partículas. Comparações entre as condições fluidodinâmicas dos processos com e sem controle foram analisadas para operações em leito fluidizado em escala de laboratorio. Para avaliar a qualidade das partículas foi utilizada uma sonda de monitoramento in-line (Parsum IPP70), onde se pôde verificar os instantes iniciais da aglomeração indesejada. Com a aplicação desde sistema automatizado foi possível associar a estabilidade da fluidização em função do elevado grau de aglomeração. O ponto de parada do processo pôde ser definido em 420 µm (inicial em 360 µm) e a partir deste o mecanismo de recobrimento acontece simultaneamente com o de aglomeração. Os parâmetros de monitoramento do regime conseguiram não somente identificar a fase inicial da defluidização, como também foi possível a partir deles, controlar o processo por Lógica Fuzzy-PI e estabilizar a operação para altas taxas de suspensão atomizadas
Abstract: The chemical, food and pharmaceutical industries have extensively used fluidization operation in many cases, due to its very attractive features that enable effective contact between the solid and fluid phase, which reflects the generation of high heat and mass transfer rates. However, the bubbling fluidization regime, which is the starting condition of the processes involved in this operation is often affected by operating conditions. Elevated temperatures, excessive moisture content of the particles and introduction of liquid into the fluidized bed may lead to instabilities in the fluid-dynamic regime and cause partial or total collapse of the bed, reducing the process efficiency. The maintenance of stable conditions of the fluidization regime for particle coating processes in fluidized beds is of fundamental importance to ensure a favorable coating efficiency and to avoid zones without movement and agglomeration of particles in the bed, because these undesirable factors compromise the mixing between the phases and therefore the quality of the final product. Within this context, the use of a monitoring system and real-time control of particle coating processes is highly desirable to allow operation in stable fluidization regimes and to ensure a uniform coating film and good condition of flowability of the solids. This doctoral thesis aims to apply the Gaussian spectral analysis methodology of the pressure fluctuation signals (Parise et al. (2008)) , for the development of control systems based on artificial intelligence (Fuzzy Logic), to monitor the stability of fluidization regime particle coating process. Comparisons between the fluid dynamic conditions of the processes with and without control were analyzed for operations in fluidized bed laboratory scale. To assess early stages of unwanted agglomeration, a monitoring in-line probe (Parsum IPP70) was used. With the application of this automated system, it was possible to associate the stability of fluidization with a high degree of agglomeration. The process stopping point could be set at 420 µm (initial in 360 µm) and after, the coating mechanism takes place simultaneously with the agglomeration one. The monitoring parameters of the system were able to identify the initial phase of defluidization, as well as it was possible to control the process by using Fuzzy Logic and to stabilize the operation for high rates of the coating suspension atomized onto the bed
Doutorado
Engenharia de Processos
Doutor em Engenharia Química
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Hegyi, Gyorgy. "Particle size determination for alpha-emitters using CR-39." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0019/MQ55065.pdf.
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Abudu, Adewunmi Tiwalade. "Adsorption and particle size studies of petroleum fluids." Laramie, Wyo. : University of Wyoming, 2009. http://proquest.umi.com/pqdweb?did=1939120981&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Sun, Guanglin. "Influence of particle size distribution on the performance of fluidized bed reactors." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/32013.
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The effect of particle size distribution (PSD) on the performance of a fluidized bed reactor was investigated using the ozone decomposition reaction, combined with the study of hydrodynamics, for fresh and spent fluid cracking catalysts, each having three particle size distributions - wide, narrow and bimodal - all with nearly the same mean diameter (60 µm), the same particle density and the same BET surface area. The superficial gas velocity was varied from 0.1 to 1.8 m/s to include the bubbling, slugging, turbulent and fast fluidization regimes. The catalytic rate constant, based on the volume of the particles, ranged from 2 to10 s⁻¹, while the static bed height was varied from 0.15 m to 1 m. Four different multi-orifice gas distributors with different hole diameters (2.2 to 5.1 mm) and hole numbers (4 and 21) were also tested to evaluate the influence of gas distributor on the performance of fluidized bed reactors.
The particle size distribution was found to play a larger role at higher gas velocities than at lower velocities. At low gas velocities (Uf ≤ 0.2 m/s), the reaction conversion was not greatly affected by the PSD. However, with an increase in gas velocity the PSD effect became larger. The wide size distribution gave the highest reactor efficiency, defined as the ratio of the volume of catalyst required in a plug flow reactor to that required in the fluidized bed reactor to achieve the same conversion, while the narrow blend gave the lowest. The differences are not solely a function of the "fines content".
The influence of particle size distribution on the hydrodynamics of fluidization was evaluated by measuring particle concentrations in voids, bubble sizes, and dense phase expansion. When the superficial gas velocity exceeded 0.1 m/s, the bed with the wide size distribution usually gave the highest particle concentration inside the voids, the smallest
bubble size and the greatest dense phase expansion at the same operating conditions. There is evidence that there is a greater proportion of "fines" present in the voids than in the overall particle size distribution. This has been explained in terms of the throughflow velocity inside bubbles being of the same order as the terminal velocity of typical "fines", causing these particles to spend longer periods of time inside the voids.
The effect of the PSD on the fluidization regime and its transitions was determined by measuring pressure fluctuations along the column. The earliest transition from bubbling or slugging to turbulent fluidization occurred in the bed of wide size distribution, while the latest corresponded to the narrow PSD.
For particles of wide size distribution, higher conversion was achieved for the turbulent and fast fluidization regimes than for the bubbling fluidization regime under otherwise identical conditions, while for particles of narrow size distribution, the dependence of conversion on regime was small. Hence, for reactors of wide PSD, the performance can be improved significantly by operating in the turbulent or fast fluidization regime, while for particles of narrow size distribution, the benefit of operating at high gas velocity is slight at best.
The PSD influence should be considered in modelling fluidized bed reactors. The "Two-Phase Bubbling Bed Model" has been modified to account for PSD effects. For the reactor of wide particle size distribution operated at high gas velocities, a single-phase axial dispersion model with closed inlet and open outlet boundary conditions appears to be suitable to predict the performance.
It was also found that a high pressure drop across the gas distributor was not sufficient to maintain good performance of the distributor. The reactor efficiency in the entry region was higher for a distributor with a greater number of orifices, even though it had a lower pressure drop, than for a distributor plate with fewer larger holes.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Silva, Silvino L. C. "Soot particle size and concentration determination from a kerosene/gaseous oxygen rocket plume." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA358997.
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Pretorius, Jan Hendrik Christoffel. "The influence of PFA particle size on the workability of cementitious pastes." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-07082005-135427/.
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Vivaldo-Lima, Eduardo. "Development of an effective model for particle size distribution in suspension copolymerization of styrene/divinylbenzene." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/NQ42885.pdf.
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Sudsakorn, Kandis. "The effect of particle size on the amount of coating received during a batch fluidized bed coating operation." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=612.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 98 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 63-68).
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Van, der Merwe J. J. "Parameters affecting accuracy and reproducibility of sedimentary particle size analysis of clays." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50054.
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Thesis (MSc)--Stellenbosch University, 2004ENGLISH ABSTRACT: The main aim of this study is to establish a standard procedure for all sedimentary particle size analysis methods specifically for clay minerals and mixtures thereof. Not only will it improve accuracy and reproducibility during clay size analysis, it will also secure comparability between different operators. As a start, all the apparatus-related parameters that can affect the accuracy and reproducibility were determined for the apparatus used, viz. the Sedigraph SOOOD. Thereafter, these parameters were kept constant, and the effects of potential material-related parameters were investigated one-by-one. First to be investigated were those parameters relating specifically to sample preparation. They were: grinding intensity, chemical dissolution of cementing materials, duration of prior soaking, salt content, centrifugal washing with polar organic liquids, deflocculant type and concentration, the effect of pH, ultrasonic time, and stirring during ultrasonic treatment. Then, the influence on accuracy and reproducibility of the physical and chemical parameters related to the suspension was determined. They were: the use of the viscosity and density of water to calibrate the apparatus in stead of those of the suspension liquid, hydrolysis of the deflocculant with suspension-ageing, and the effect of solid concentration on hindered settling. During this investigation a novel method was developed to enable faster and more accurate pycnometric density determinations. Next, the unique characteristics of clays, which can influence the results of sedimentary particle size analyses, were examined. Serious problems are encountered with the accuracy of the analyses of some clay types abundantly found in nature, viz. the smectites and mixed-layered clay minerals. Due to their swelling in water, and variations in the amounts of their crystal layers, they experience unpredictable changes in particle size. The latter is caused by the following external factors: clay type, humidity, type of exchange cation, electrolyte concentration, clay concentration, pH, deflocculant type and concentration, pressure history of the swell-clay suspension, and ageing of the suspension. The effect of each of them on the accuracy and reproducibility of the sedimentary particle size analysis of clays are investigated in detail. Another problem that influences the accuracy of the sedimentary methods is that owing to swelling, the densities of smectites and mixed-layered clays change by varying degrees when suspended in water. It is, however, impossible to pycnometrically determine the density of a swell-clay since it absorbs a part of the water used for its volume determination. To solve this problem, a novel method was devised to calculate swell-clay density. This method makes use of existing Monte Carlo simulations of the swelling mechanism of montmorillonite. During all sedimentary methods, an average clay density is normally used to calculate the particle size distribution of clay mixtures. However, if there is a large enough difference between the calculated average density and that of a component, then inaccurate results will be recorded. The magnitude of this effect was investigated for a few self-made clay mixtures, which consisted of different proportions of kaolinite, illite, and montmorillonite. Based on all the above results, a practical approach to, and a standard methodology for all the sedimentary methods of particle size analysis of clay minerals are presented. Additionally, a condensed summary is provided in table-form, which contains the magnitudes of the errors associated with each of the parameters that were examined.
AFRIKAANSE OPSOMMING: Die doel van hierdie studie is om 'n standaard prosedure daar te stel vir alle sedimentêre metodes van partikelgrootte analise, spesifiek vir gebruik met kleiminerale en mengsels daarvan. So 'n standaard prosedure sal die akkuraatheid en herhaalbaarheid van klei-analises verbeter, en die vergelykbaarheid tussen verskillende operateurs verseker. Aanvanklik is slegs die parameters bepaal wat die akkuraatheid en herhaalbaarheid van die gekose apparaat (Sedigraph 5000D) kan beïnvloed. Daarna is al hierdie parameters konstant gehou, en is die potensiële effekte van die moontlike materiaal-verwante parameters een na die ander ondersoek. Eerstens is die invloed van monstervoorbereiding op akkuraatheid en herhaalbaarheid bepaal. Verskillende parameters nl. maal-intensiteit, chemiese oplossing van sementerende materiale, sentrifugale wassing met polêre organiese vloeistowwe, tipe ontvlokker en konsentrasie, die effek van pH, ultrasoniese tyd en die effek van roer tydens ultrasonikasie is ondersoek. Vervolgens is die invloed op die akkuraatheid en herhaalbaarheid van die fisiese en chemiese parameters verwant aan die suspensie bepaal. Hierdie parameters was nl. die gebruik van die viskositeit en digtheid van water in plaas van dié van die suspensievloeistof, hidrolise van die ontvlokker tydens suspensieveroudering, asook die effek van vastestof-konsentrasie op belemmerde uitsakking. Gedurende hierdie ondersoek is ook 'n nuwe metode ontwikkel wat vinniger, en meer akkurate piknometriese digtheidsbepalings moontlik maak. Die unieke eienskappe van kleie wat die resultate van sedimentêre metodes van partikelgrootte analises kan beïnvloed, is volgende ondersoek. Tydens die analises van party kleie wat baie volop in die natuur voorkom, nl. die smektiete en menglaag-kleie, word ernstige akkuraatheids-probleme ondervind. Hul swelling in water, tesame met variasies in hul aantal kristal-lagies, veroorsaak onvoorspelbare verandering van hul partikelgroottes. Laasgenoemde word deur die volgende eksterne faktore veroorsaak: klei tipe, humiditeit, tipe uitruil-katioon, elektrolietkonsentrasie, kleikonsentrasie, pH, ontvlokker-tipe en konsentrasie, drukgeskiedenis van 'n swelklei-suspensie, en veroudering van die suspensie. Die effek van elk op die akkuraatheid en herhaalbaarheid van die sedimentêre partikelgrootte analises van kleie word in detail bespreek. 'n Verdere probleem wat die akkuraatheid van sedimentêre metodes beïnvloed, is dat wanneer smektiete en menglaag-kleie in water gesuspendeer word, hulle digthede in verskillende mates weens swelling verander. Dit is egter onmoontlik om die digtheid van swelkleie in water piknometries te bepaal, omdat swelklei 'n gedeelte van die water absorbeer wat gebruik moet word om die kleivolume mee te bepaal. Om hierdie probleem op te los, is 'n nuwe metode ontwikkelom die digtheid van swelkleie mee te bereken. Die metode maak gebruik van reedsbestaande Monte Carlo simulasies van die swelling van montmorillonite. Tydens alle sedimentêre metodes word normaalweg van 'n gemiddelde kleidigtheid gebruik gemaak om die partikelgrootte-verspreiding van kleimengsels mee te bereken. Indien die berekende gemiddelde digtheid egter genoegsaam met dié van 'n kleikomponent verskil, sal onakkurate resultate verkry word. Hierdie effek is ondersoek vir 'n paar selfgemaakte kleimengsels wat uit verskillende hoeveelhede kaoliniet, illiet, en montmorilloniet bestaan het. Laastens word 'n praktiese benadering en 'n standaard metode vir alle sedimentêre metodes voorgestel, wat gebaseer is op al die bogenoemde resultate. 'n Verkorte opsomming, met die groottes van die foute geassosieer met elke parameter wat ondersoek is, word laastens in tabelvorm verskaf.
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Glen, Andrew. "A new optical particle counter for in situ measurements of stratospheric aerosol size distributions." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1400968731&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Hunt, Eden Meyer. "The formation of nanosized metallic particles in oxide substrates via ion implantation-induced reduction." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/19415.
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Garcia, Nancy. "Analysis of number and mass concentration of coarse and fine particulate matter measurements within a heavy-duty diesel truck stop." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Berakis, Michael T. "The connection between the current penetration based national ambient air quality standard and dose can be considered questionable." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=1111.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains vii, 301 p. : ill. Includes abstract. Includes bibliographical references (p. 146-48).
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Smith, David A. "Effect of particle shape on grain size, hydraulic, and transport characteristics of calcareous sand." Thesis, University of Hawaii at Manoa, 2003. http://proquest.umi.com/pqdweb?index=0&did=764803691&SrchMode=1&sid=2&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1233275673&clientId=23440.
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Uahengo, Foibe Dimbulukwa Lawanifwa. "Estimating particle size of hydrocyclone underflow discharge using image analysis." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86365.
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Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Hydrocyclones are stationary separating machines that separate materials based on centrifugal separation and are widely used in chemical engineering and mineral processing industries. Their design and operation, compact structure, low running costs and versatility all contribute to their applications in liquid clarification, slurry thickening, solid washing and classification. With any of these operations, the overall profitability of the process relies on the effective control of the process equipment. However, in practice, hydrocyclones are difficult to monitor and control, owing to the complexity and difficulty in measuring internal flows in the equipment. Several studies have indicated that hydrocyclone underflow images can be used to monitor process conditions. The research described in this thesis considers the use of image analysis to monitor particle size and solids concentration in the underflow discharge of a hydrocyclone. The experimental work consisted of laboratory and industrial-based case studies. The laboratory cyclone used was a 76 mm general laboratory cyclone. A Canon EOS 400D digital camera was used for the underflow imaging. Image features such as pixel intensity values, underflow discharge width and grey level co-occurrence matrix (GLCM) were extracted from the images using MATLAB Toolbox software. Linear discriminant analysis (LDA) and neural network (NN) classification models were used to discriminate between different PGM ore types based on features extracted from the underflow of the hydrocyclone. Likewise, multiple linear regression and neural network models were used to estimate the underflow solids content and mean particle size in the hydrocyclone underflow. The LDA model could predict the PGM ore types with 61% reliability, while the NN model could do so with a statistically similar 62% reliability. The multiple linear regression models could explain 56% and 40% of variance in the mean particle size and solids content respectively. In contrast, the neural network model could explain 67% and 45% of the variance of the mean particle size and solids content respectively. For the industrial system, a 100% correct classification was achieved with all methods. However, these results are regarded as unreliable, owing to the insufficient data used in the models.
AFRIKAANSE OPSOMMING: Hidrosiklone is stasionêre skeidingsmasjiene wat materiale skei op grond van sentrifugale skeiding en word algemeen gebruik in die chemiese ingenieurswese en mineraalprosessering industrieë. Hul ontwerp en werking, kompakte struktuur, lae bedryfskoste en veelsydigheid dra by tot hul gebruik vir toepassings in vloeistofsuiwering, slykverdikking, vastestof wassing en klassifikasie. In enige van hierdie prosesse hang die oorhoofse winsgewendheid van die proses af van die effektiewe beheer van die prosestoerusting. In die praktyk is hidrosiklone egter moeilik om te monitor en beheer weens die kompleksiteit en moeilikheidsgraad daarvan om die interne vloei in die apparaat te meet. Verskeie studies het aangedui dat hidrosikloon ondervloeibeelde gebruik kan word om die proseskondisies te monitor. Die navorsing beskryf in hierdie tesis maak gebruik van beeldanalise moniteringstegnieke om die ertstipes en grootte- verspreidingsgebiede/ klasse van die ondervloei afvoerpartikels te bepaal. Sodoende word ‘n grondslag gelê vir verbeterde sikloon monitering en beheer. Die eksperimentele werk het bestaan uit beide laboratorium en industrieel-gebaseerde studies. Die laboratorium sikloon wat gebruik is, was ‘n 76 mm algemene laboratorium sikloon. ‘n Canon EOS 400D digitale kamera is gebruik om die hidrosikloon ondervloei beelde vas te vang. Beeldeienskappe soos beeldelement intensiteitswaardes, ondervloei afvoerwydte en grysvlak mede-voorkoms matriks is onttrek uit die beelde deur gebruik te maak van MATLAB Toolbox sagteware. Lineêre diskriminantanalise (LDA) en neural netwerk (NN) klassifikasiemodelle is gebou om te onderskei tussen die verskillende PGM ertse en gebaseer op veranderlikes wat afgelei is uit beelde van die ondervloei van die sikloon. Net so is daar ook gebruik gemaak van lineêre regressie- en neural netwerkmodelle om die vasestofkonsentrasie en gemiddelde partikelgrootte in die ondervloei van die sikloon te beraam. Die LDA model kon die PGM ertstipes met 61% betroubaarheid voorspel, terwyl die neural netwerkmodel dit kon doen met statisties dieselfde betroubaarheid van 62%. Die lineêre regressiemodelle kon onderskeidelik 56% en 40% van die variansie in die gemiddelde partikelgrootte en vastestofkonsentrasie verduidelik. In teenstelling iermee, kon die neurale netwerkmodel 67% en 45% van die variansie in die gemiddelde partikelgrootte en vastestofkonsentrasie verduidelik. In die nywerheidstelsel kon beide tipe modelle perfekte onderskeid tref tussen die partikelgroottes wat gemeet is op opeenvolgende dae van die bedryf van die siklone. Hierdie resultate is egter nie betroubaar nie, a.g.v. die beperkte hoeveelheid data wat beskikbaar was vir modellering.
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Cao, Zihan. "Determination of Particle Size Distribution of Particulate Matter Emitted from a Layer Operation in Southeast U.S." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-07302009-201630/.
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This thesis reports a field study on characterizing particle size distribution (PSD) of particulate matter (PM) emitted from a commercial layer operation in the Southeastern U.S. across three seasons from October of 2008 to April of 2009. Six low-volume (1m3/h) total suspended particulate (TSP) samplers were used to collect PM samples in two high-rise layer houses. A laser diffraction particle size analyzer (LS13 320) at North Carolina State University (NCSU), a laser scattering particle size analyzer (LA-300) at University of Illinois at Urbana-Champaign (UIUC) and a Coulter Counter Multisizer 3 (CCM 3) at Texas A&M University (TAMU) or USDA-ARS cotton production & processing unit in Lubbock, TX were used to measure PSD of PM samples collected by the TSP samplers. Particle size distributions measured by these three instruments were compared. Results of the study indicate that TSP concentrations across the three seasons ranged from 888 to 5333 µg/m3. Total suspended particulate concentration was affected by season, animal activity, floor, and equivalent air flow rate factor. It was observed that TSP concentration in winter was higher than in spring; concentration on the second floor was higher than that on the first floor; the more active the animals were, the higher the TSP concentration; and the more the fans were on, the lower the concentration. Compared with PM concentration, PSD (characterized by the mass medium diameter, MMD, and geometric standard deviation, GSD) was affected by season, animal activity, floor and equivalent flow rate factor to a lesser extent. Overall MMDs of PM samples collected in fall, winter and spring, measured by the laser diffraction particle size analyzer were 19.21±1.27 µm, 17.13±0.81µm and 18.44±1.44µm, respectively. Geometric standard deviation (GSD) was relatively constant and not affected by those factors (season, animal activity, floor, and equivalent air flow rate factor). The overall GSD was 2.65±0.08. Significant but constant differences in MMDs and GSDs were detected when comparing PSDs measured by the different instruments. In general, the LA-300 provided the largest MMDs, whereas the CCM 3 gave the smallest MMDs. The LS13 320 provided the largest GSDs, whereas the CCM 3 gave the smallest.
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Tungapindi, Navina. "Classification of fine particles using a Taylor-Couette device." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2009. http://scholarsmine.mst.edu/thesis/pdf/Tungapindi_09007dcc80601425.pdf.
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Thesis (M.S.)--Missouri University of Science and Technology, 2009.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed February 18, 2009) Includes bibliographical references (p. 54-56).
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Agagliate, Jacopo. "A Mie-based flow cytometric size and real refractive index determination method for natural marine particle populations." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=28674.
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Following the path of combining Mie theory and flow cytometry to assign size and refractive index to suspended particles in the steps of Ackleson & Spinrad (1988) and, more recently, Green et al. (2003a, 2003b), a Mie-based flow cytometry (FC) method was developed to retrieve particle size distributions (PSDs) and real refractive index (rRI) information in natural waters. The need for a technique capable of directly assessing both size and real refractive index of the particles was first established by carrying out a sensitivity analysis of the effect a spectrally complex refractive index and log-normal variations to commonly employed PSD models have on the optical behaviour of the particle population. The Mie-based FC method proper was then developed and tested, initially against standard particles of known diameter and rRI and secondly on two datasets, one of algal culture samples (AC dataset) and one of natural seawater samples collected in UK coastal waters (UKCW dataset).The method retrieved PSDs and real refractive index distributions (PRIDs) for both datasets. FC PSDs were validated against known algal sizes for AC samples and against independent PSDs measured via laser diffractometry for UKCW samples. PRIDs were then combined with FC PSDs and fed into Mie-based forward optical modelling to reconstruct bulk IOPs. These achieved broad agreement with independent IOP measurements, lending further support to the results of the FC method and to the employment of Mie theory within the context of optical modelling of natural particle populations. Furthermore, the unique insight offered by the FC method in terms of PSD and PRID determination allowed for the assessment of the individual contribution of particle subpopulations to the bulk IOPs, both by size (small/large particle fractions) and by particle type (inorganic/organic/fluorescent fractions). Lastly, PSDs and PRIDs were combined with literature-derived models of particle density, cell organic carbon and chlorophyll-A content, in an effort to explore the biogeochemical properties of the particle populations within the UKCW dataset. The models successfully estimated independent measurements of particulate suspended matter and (after an optimisation procedure) of organic carbon and chlorophyll-A content.
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Zheng, Feng. "Thermophoretic force measurements of spherical and non-spherical particles /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/9874.
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Zheng, Dongqin. "Evaluation and development of data assimilation in atmospheric dispersion models for use in nuclear emergencies." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39346031.
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Zheng, Dongqin, and 鄭冬琴. "Evaluation and development of data assimilation in atmospheric dispersion models for use in nuclear emergencies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39346031.
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Großpietsch, Uwe. "Größenbestimmung, Syntheseoptimierung und Polymerhüllen-Charakterisierung an Nanokapseln - Particle size determination, preparation optimization and polymer wall characterisation of nanocapsules." Gerhard-Mercator-Universitaet Duisburg, 2002. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-07262002-131932/.
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This work deals with the preparation and characterisation of poly(n-butyl-2-cyanacrylate) nanocapsules. The mean applications of these particles are their use as drug-carriers, in order to increase the efficiency and to reduce the side effects of pharmaceuticals. By coupling size exclusion chromatography with multi angle laser light scattering a procedure for size determination of nanocapsules is developed. In this connection the analysis of the light scattering data is discussed in detail. Concerning the optimization of the capsule preparation, the influences of different parameters (components concentration, type of stirrer and sample preparation) on the size and size distribution of the nanocapsules are determined. Regarding the characterisation of the polymer cover, the wall thickness as well as the molecular weight distribution of the polymer are analysed. Further, the capsule wall is simulated by a planar polymer film. Rheologic and H-NMR investigations on this film allow to observe the kinetics of wall formation. The rheologic measurements give additional information about the viscoelastic properties and the cross linkage of the polymer.
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Stamp, Jennifer D. "Associations between stream macroinvertebrate communities and surface substrate size distributions." Ohio : Ohio University, 2004. http://www.ohiolink.edu/etd/view.cgi?ohiou1103232587.
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Mei, Chen-Jung Judy. "Determination of microparameters for discrete element modelling of granular materials with varying particle size using one-dimensional compression testing." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/64163.
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A research program was undertaken to study the effect of particle size on the mechanical response of granular materials, with particular emphasis on supporting the study of the effect of backfill particle size on the soil-pipe interaction of buried pipelines. In this regard, laboratory one-dimensional compression tests of different-sized glass beads and crushed granite were conducted. One-dimensional compression tests on glass beads were simulated in a numerically equivalent discrete element model (DEM), in order to identify suitable DEM particle stiffness microparameters able to reproduce the corresponding laboratory results.
Effects of particle size on bulk material behavior were first studied through the analysis of experimental one-dimensional compression test results of both glass beads and crushed granite. Axial stress-strain response of both materials revealed that an increase in particle size of a granular material matrix increased the stiffness of the overall granular matrix. Results also revealed that smaller particles resulted in higher side wall friction values than larger particles of the same material type. The dependence of constrained modulus and shear modulus on effective confining stress determined experimentally from all laboratory tests were in general agreement with relationships previously proposed by other researchers.
Numerical simulations of the laboratory specimens were conducted using DEM; i.e. the numerical models were calibrated against experimental results obtained from one-dimensional compression tests of different-sized glass beads to determine suitable particle stiffness microparameters for granular materials of differing particle sizes. The findings indicated that the numerical value of particle stiffness microparameters increased with increasing particle size. In agreement with the experimental results, DEM results also showed that an increase in particle size resulted in increased stiffness of the overall granular matrix under one-dimensional compression. Through evaluation of numerical results, it was proposed that a preliminary relationship between “average” constrained modulus and particle stiffness could be established.
Results indicate that DEM simulations of one-dimensional compression tests can be successfully used to calibrate DEM particle stiffness microparameters. The findings suggest that particle stiffness microparameters should be carefully selected for DEM simulations of granular materials of different-sized particles and, in turn, be utilized in quantitative analysis of geotechnical engineering problems.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Heitkamp, Kyle Matthew. "Evaluation of the ClearSky smoke dispersion ensemble forecast system for agricultural field burning in Eastern Washington and Northern Idaho." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Spring2006/k%5Fheitkamp%5F050306.pdf.
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Latti, Anna Dewetia. "The textural effects of multiphase mineral systems in liberation measurement /." [St. Lucia, Qld.], 2006. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19407.pdf.
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Wang, Gonghui. "AN EXPERIMENTAL STUDY ON THE MECHANISM OF FLUIDIZED LANDSLIDE : WITH PARTICULAR REFERENCE TO THE EFFECT OF GRAIN SIZE AND FINE-PARTICLE CONTENT ON THE FLUIDIZATION BEHAVIOR OF SANDS." 京都大学 (Kyoto University), 1999. http://hdl.handle.net/2433/86415.
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Veeravalli, Murali Srinidhi. "A microfluidic Coulter counting device for metal wear detection in lubrication oil." Akron, OH : University of Akron, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1226866175.
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Thesis (M.S.)--University of Akron, Dept. of Mechanical Engineering, 2008."December, 2008." Title from electronic thesis title page (viewed 12/9/2009) Advisor, Jiang John Zhe; Faculty Readers, Joan Carletta, Dane Quinn; Department Chair, Celal Batur; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Chen, Weixia. "Détermination des propriétés thermophysiques de matériaux granulaires /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1998. http://theses.uqac.ca.
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Rebata-Landa, Veronica. "Microbial Activity in Sediments: Effects on Soil Behavior." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19720.
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Thesis (Ph.D)--Civil and Environmental Engineering, Georgia Institute of Technology, 2008.Committee Chair: Santamarina, J. Carlos; Committee Member: Burns, Susan; Committee Member: Frost, David; Committee Member: Mitchell, James; Committee Member: Rix, Glenn; Committee Member: Sobecky, Patricia.
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Van, Heerden Jacobus Hendrik Francois. "Direct measurement of pore fluid suction in gold mine tailings." Diss., Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-09212005-135324/.
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Song, Di. "Study of Electrostatic Charging and Particle Wall Fouling in a Pilot-scale Pressurized Gas-Solid Fluidized Bed up to Turbulent Flow Regime." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36007.
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In gas-solid fluidized beds, the generation of electrostatic charges due to continuous contacts between fluidizing particles, and the particles and the fluidization vessel wall, is unavoidable. Industrial operations, such as the production of polyethylene, are susceptible to significant operational challenges caused by electrostatics including reactor wall fouling, a problem known as “sheeting”. The formation of particle sheets can require shutdown periods for clean-up which results in significant economic losses. To gain a better understanding of the underlying mechanisms of electrostatic charging in gas-solid fluidized beds, in an attempt to eliminate or minimize this problem, a pilot-scale pressurized gas-solid fluidization system was designed and built, housing an online electrostatic charge measurement technique consisting of two Faraday cups. The system permits the study of the degree of particle wall fouling at pressures and temperatures up to 2600 kPa and 100°C, respectively, and gas velocities up to 1 m/s (covering a range including turbulent flow regime). The system also allowed, for the first time, the measurement of the fluidizing particles’ mass, net charge and size distribution in various regions of the bed, especially those related to the wall coating under the industrially relevant operating conditions of high pressures and gas velocities. Experimental trials were carried out using polyethylene resin received from commercial reactors to investigate the influence of pressure and gas velocity on the bed hydrodynamics and in turn, the degree of bed electrification.
Mechanisms for particle charging, migration and adherence to the column wall were proposed. The size distribution of the gas bubbles shifted towards smaller bubbles as the operating pressure was raised. Thus, higher pressures lead to greater mixing within the bulk of the bed and resulted in a higher degree of particle wall fouling. Moreover, the extent of wall fouling increased linearly with the increase in gas velocity and as the bed transitioned to turbulent regime, due to the increase in particle-wall contacts. Bipolar charging was observed especially within the wall coating with smaller particles being negatively charged. Overall, particle-wall contacts generated negatively charged particles resulting in a net negative charge in the bed, whereas particle-particle contacts generated positively and negatively charged particles resulting in no net charge when entrainment was negligible. The formation of the wall layer and its extent was influenced by the gravitational and drag forces balancing the image force and Coulomb forces (created by the net charge of the bed and the metallic column wall as the attraction between oppositely charged particles).
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Assemi, Shoeleh 1963. "Use of flow field-flow fractionation for the characterisation of humic substances." Monash University, Dept. of Chemistry, 2000. http://arrow.monash.edu.au/hdl/1959.1/9028.
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Salim, Md Wadud. "Deformation and degradation aspects of ballast and constitutive modelling under cyclic loading." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050215.114659/index.html.
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Manktelow, Kevin Lee. "Dispersion analysis of nonlinear periodic structures." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/51936.
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The present research is concerned with developing analysis methods for analyzing and exploring finite-amplitude elastic wave propagation through periodic media. Periodic arrangements of materials with high acoustic impedance contrasts can be employed to control wave propagation. These systems are often termed phononic crystals or metamaterials, depending on the specific design and purpose. Design of these systems usually relies on computation and analysis of dispersion band structures which contain information about wave propagation speed and direction. The location and influence of complete (and partial) band gaps is a particularly interesting characteristic. Wave propagation is prohibited for frequencies that correspond to band gaps; thus, periodic systems behave as filters, wave guides, and lenses at certain frequencies. Controlling these behaviors has typically been limited to the manufacturing stage or the application of external stimuli to distort material configurations. The inclusion of nonlinear elements in periodic unit cells offers an option for passive tuning of the dispersion band structure through amplitude-dependence. Hence, dispersion analysis methods which may be utilized in the design of nonlinear phononic crystals and metamaterials are required. The approach taken herein utilizes Bloch wave-based perturbation analysis methods for obtaining closed-form expressions for dispersion amplitude-dependence. The influence of material and geometric nonlinearities on the dispersion relationship is investigated. It is shown that dispersion shifts result from both self-action (monochromatic excitation) and wave-interaction (multi-frequency excitation), the latter enabling dynamic anisotropy in periodic media. A particularly novel aspect of this work is the ease with which band structures of discretized systems may be analyzed. This connection enables topology optimization of unit cells with nonlinear elements. Several important periodic systems are considered including monoatomic lattices, multilayer materials, and plane stress matrix-inclusion configurations. The analysis methods are further developed into a procedure which can be implemented numerically with existing finite-element analysis software for analyzing geometrically-complex materials.
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Kwok, Philip Chi Lip. "Electrostatics of aerosols for inhalation." Faculty of Pharmacy, 2007. http://hdl.handle.net/2123/1934.
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PhDElectrostatics of aerosols for inhalation is a relatively new research area. Charge properties of these particles are largely unknown but electrostatic forces have been proposed to potentially influence lung deposition. Investigation on the relationship between formulation and aerosol charging is required to understand the fundamental mechanisms. A modified electrical low pressure impactor was employed to measure the particles generated from metered dose inhalers and dry powder inhalers. This equipment provides detailed size and charge information of the aerosols. The particles were sized by impaction onto thirteen stages. The net charges in twelve of the size fractions were detected and recorded by sensitive electrometers. The drug deposits were quantified by chemical assay. The aerosol charge profiles of commercial metered dose inhalers were product-dependent, which was due to differences in the drug, formulation, and valve stem material. The calculated number of elementary charges per drug particle of size ≤ 6.06 μm ranged from zero to several ten thousands. The high charge levels on particles may have a potential effect on the deposition of the aerosol particles in the lung when inhaled. New plastic spacers marketed for use with metered dose inhalers were found to possess high surface charges on the internal walls, which was successfully removed by detergent-coating. Detergent-coated spacer had higher drug output than the new ones due to the reduced electrostatic particle deposition inside the spacer. Particles delivered from spacers carried lower inherent charges than those directly from metered dose inhalers. Those with higher charges might be susceptible to electrostatic forces inside the spacers and were thus retained. The electrostatic low pressure impactor was further modified to disperse two commercial Tubuhaler® products at 60 L/min. The DPIs showed drug-specific responses to particle charging at different RHs. The difference in hygroscopicity of the drugs may play a major role. A dual mechanistic charging model was proposed to explain the charging behaviours. The charge levels on drug particles delivered from these inhalers were sufficiently high to potentially affect deposition in the airways when inhaled. Drug-free metered dose inhalers containing HFA-134a and 227 produced highly variable charge profiles but on average the puffs were negatively charged, which was thought to be due to the electronegative fluorine atoms in the HFA molecules. The charges of both HFAs shifted towards neutrality or positive polarity with increasing water content. The spiked water might have increased the electrical conductivity and/or decreased the electronegativity of the bulk propellant solution. The number of elementary charges per droplet decreased with decreasing droplet size. This trend was probably due to the redistribution of charges amongst small droplets following electrostatic fission of a bigger droplet when the Raleigh limit was reached.
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Martí, Roura Mireia. "Dinàmica del carboni i el nitrogen en brolles i prats secs mediterranis després del foc." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/128924.
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Les zones forestals han augmentat a la regió mediterrània al llarg de les últimes dues dècades degut a l’abandonament de l’agricultura. Això, juntament amb l’augment de períodes d’intensa sequera degut a l’efecte del canvi climàtic, ha fet augmentar la freqüència i la intensitat dels focs forestals. Els focs forestals tenen un efecte directe sobre la biogeoquímica dels sòls modificant-ne la qualitat i la quantitat de la matèria orgànica i d’altres macroelements com el nitrogen, imprescindible per la regeneració de la comunitat vegetal. Malgrat la major part de la biomassa vegetal es crema durant un incendi, una part important de matèria orgànica pot ser dipositada de nou al sòl en forma de residus parcialment cremats formant estructures molt recalcitrants. D’altra banda, el nitrogen mineral alliberat després del foc, pot quedar retingut físicament, mitjançant l’associació amb partícules fines del sòl (llims i argiles) o químicament, a partir de la inclusió a la matèria orgànica recalcitrant del sòl, evitant-ne així el seu rentat i, per tant, la pèrdua de l’ecosistema.
Per tal d’entendre millor els canvis en la matèria orgànica del sòl i la dinàmica del N mineral alliberat després del foc, es van seleccionar tres comunitats vegetals diferents (prat de llistó, prat de llistó amb argelaga i brolla de romaní) amb diferències en quant a la proporció de plantes herbàcies i llenyoses i amb la presència o absència d’argelaga (planta fixadora de nitrogen atmosfèric). En aquestes comunitats s’hi van realitzar una sèrie de cremes experimentals i, posteriorment, les cendres van ser marcades amb un isòtop estable del nitrogen (15N). Es van realitzar mostrejos posteriors durant 12 anys per tal d’observar els efectes del foc a llarg termini. Amb els sòls obtinguts es va realitzar: (1) un estudi de la dinàmica del carboni a llarg termini mitjançant una sèrie de simulacions utilitzant el model Roth C, (2) un seguiment del traçador 15N al sòl i a la vegetació al llarg del temps i a diferents profunditats, (3) un estudi de la protecció física i química a la que és sotmesa el N mineral alliberat (marcat amb 15N) mitjançant un fraccionament físic granulomètric i una hidròlisi àcida posterior per observar el grau de recalcitrància d’aquest N incorporat i, finalment, (4) un estudi de la matèria orgànica pirogènica formada per compostos refractaris considerats inerts i de la incorporació del N mineral alliberat després del foc a aquesta matèria orgànica.
La baixa intensitat dels focs forestals que van afectar les brolles i prats secs va provocar que els canvis quantitatius en el C orgànic i en el N total del sòl no fossin gaire destacats després del foc i que la recuperació davant d’aquests canvis fos molt ràpida. A més l’estudi a llarg termini va incloure un període prolongat de sequera que va provocar l’augment d’aports de matèria orgànica al sòl. Per altra banda, una bona part del marcatge amb 15N aplicat pel seguiment del N mineral alliberat just després del foc, al cap de 12 anys, encara estava retingut al sòl a les comunitats vegetals sense plantes lleguminoses. En canvi, la presència de lleguminoses va afavorir les pèrdues de 15N des del primer any després del foc i també durant el període de sequera. Després del foc es va observar un augment de N a les fraccions granulomètriques intermèdies com a conseqüència de l’entrada de material cremat particulat mentre que el N mineral alliberat després del foc es va incorporar principalment a la fracció més grollera i a la fracció més fina del sòl. El N mineral incorporat a les fraccions fines va associar-se a la matèria orgànica més làbil tot i la protecció física que presenten aquestes partícules. Part del N mineral alliberat després del foc va ser ràpidament incorporat a les estructures més refractàries de la matèria orgànica del sòl, però amb variacions al llarg del temps, qüestionant així la permanència al sòl d’aquest tipus de compostos orgànics.Forestation has increased in the Mediterranean basin over the last two decades, due to the abandonment of formerly agriculturally used areas. This trend and the occurrence of intense drought periods have led to an increase in the frequency and intensity of wildfires. Fires have a direct effect on soil biogeochemistry, promoting changes on quantity and quality of organic matter and other macroelements such as nitrogen. Although most of a plant biomass is burned during a forest fire, some of it can be accumulated in the soil in recalcitrant form. Mineral nitrogen delivered after fire can be physically retained in soil by association with fine particles (silts and clays) or chemically retained with recalcitrant organic matter. In order to better understand changes in soil organic matter and mineral nitrogen, three different plant communities were selected: grassland (Brachypodium retusum), mixed shrubgrassland (B. retusum and Genista scorpius ) and shrubland (Rosmarinus officinalis). We set experimental fires and then monitored the fate of a 15N-tracer applied to the mineral nitrogen pool over 12 years. Thus, we studied: (1) carbon dynamics in a long term by Roth C simulations, (2) the fate of 15N in plants and soil at different depths, (3) physical and chemical protection of mineral nitrogen by soil size fractionation and acid hydrolysis and, finally (4) pyrogenic organic matter and the incorporation of mineral nitrogen delivered after fire into recalcitrant organic matter. Due to the low intensity of the experimental fires, small changes in organic carbon and total nitrogen content were detected and recuperation from these changes was fast. Moreover, the long-term study included a long drought period which promoted increases in organic matter inputs to soil. On the other hand, a large amount of 15N applied just after fire was still retained in soils after 12 years, but only in plant communities without legumes. In mixed shrubgrassland the presence of legumes (G. scorpius) promoted 15N loss from the first year after fire and also during the drought period. Fire had a shredding effect on organic matter and mineral nitrogen distributed to fine particles associated to the labile organic matter. Part of the mineral nitrogen delivered after fire was incorporated into refractory particles, but the temporal variation of this newly incorporated nitrogen questioned the stability of those highly resistant compounds in soil.
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Prado, Gustavo Silva do. "Concepção e estudo de uma unidade compacta para tratamento preliminar de esgoto sanitário composta por separador hidrodinâmico por vórtice e grade fina de fluxo tangencial." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-14112006-135556/.
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Atualmente, existe uma tendência entre os projetistas brasileiros de valorizar a etapa de tratamento preliminar em projetos de novas estações de tratamento de esgoto (ETE). Neste ensejo foi concebido, construído e estudado um protótipo, em escala plena, de uma unidade composta de separador hidrodinâmico por vórtice (SHV) empregado como desarenador e grade fina cilíndrica de fluxo tangencial. Estudos acerca da hidrodinâmica da unidade, fundamentados em ensaios de estímulo-resposta com traçador (sal de cozinha) e simulações computacionais do padrão de escoamento em software de dinâmica dos fluidos computacional, demonstrou que ao se operar a unidade com taxas de aplicação superficial (TAS) de 764 'M POT.3'/'M POT.2'd; 1.146 'M POT.3'/'M POT.2'd e 1.528 'M POT.3'/'M POT.2'd o regime de macro-mistura do padrão de escoamento que se desenvolve no SHV aproximou-se do plug-flow, porém com certo grau de mistura que diminuiu com o aumento da TAS. Nesta pesquisa, foram desenvolvidos dois métodos um para determinação da concentração de areia no esgoto sanitário e outro para determinação da distribuição granulométrica dos grãos dessa areia. Ambos foram empregados na avaliação de desempenho da unidade de tratamento preliminar desenvolvida, que foi realizada na estação elevatória de ETE Jardim das Flores do município de Rio Claro, SP. Durante esta fase da pesquisa, o SHV demonstrou enorme potencialidade na remoção de areia para as TAS de 764 'M POT.3'/'M POT.2'd; 1.146 'M POT.3'/'M POT.2'd e 1.528 'M POT.3'/'M POT.2'd, porquanto, além de não remover significativamente matéria orgânica particulada (medida em termos de concentração de sólidos suspensos voláteis) presentes no esgoto sanitário, a unidade atingiu eficiências de remoção de grãos de areia de tamanho maior ou igual a 200 'mü'm entre 85% e 95%. Entretanto, a grade fina cilíndrica de fluxo tangencial (auto-limpante) revelou-se inviável.Currently, there is a trend among the brazilian designers of valorizing the preliminary treatment in recently designed wastewater treatment plants (WWTP). In this context, a full scale prototype of a unit made up of a hydrodynamic vortex separator (HVS) applied as a degritter and a tangential flux fine screening was designed, built and evaluated. Research about the hydrodynamic of the prototype, based on stimulus-response essays with a salt tracer (sodium chloride) and computational simulations of the flow pattern using the computational fluid dynamic (CFD) software, showed that the macro mixture regime of the flow was similar to a plug-flow when the unit was operated with superficial loading rates (SLR) of 746 'M POT.3'/'M POT.2'd; 1.146 'M POT.3'/'M POT.2'd and 1.528 'M POT.3'/'M POT.2'd, however, the flow presented a certain mixture degree that reduced with the SLR increase. In this research, two methods were developed: one for the determination of grit concentration in sewage and another one for the assessment of grit grading. Both methods were used on the evaluation of the HVS prototype efficiency, which was carried out at Jardim das Flores WWT, in the city of Rio Claro, SP. During this phase of the research, the HVS presented a great potential for grit removal when the SLR of 746 'M POT.3'/'M POT.2'd; 1.146 'M POT.3'/'M POT.2'd and 1.528 'M POT.3'/'M POT.2'd were applied; for the reason that, besides not significantly removing the particulate organic matter present in sewage (measured as volatile suspended solids), the unit achieved grit removal efficiencies in the range of 85% to 95% for grit equal to or large than 200 'mü'm. However, the tangential flux cylindrical fine screening (self cleaning) did not reveal feasibility.
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Sookai, Suren. "The effect of particle properties on fluidized bed hydrodynamics and entrainment." Thesis, 2007. http://hdl.handle.net/10413/2244.
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This study focuses on the effect that particle properties (size, density and shape) have on
fluidized bed hydrodynamics and entrainment rate. The experimental work was carried out using two Plexiglas columns having internal diameters of 0.05 m and 0.14 m respectively and a total height of 6 m from the gas distributor. The particle density was in the range 1300 to 4600 kg/m3, the Sauter mean diameter was in the range 23 to 60 um and the fines content (% < 22 um) was in the range 1 to 29 %. Particle shapes, which ranged from angular to
spherical, were characterized by image analysis of SEM photographs. Air was used, as the fluidizing gas and the superficial velocity was kept constant at 0.38 m/s in the 0.05 m column. In the 0.14 m column it was varied in the range 0 to 0.8 m/s. The dense-phase voidage, bubble fraction and entrainment rate of the powders were measured at ambient conditions. In general it was found that the bubble fraction and entrainment rate increased
with an increase in the superficial gas velocity. The dense phase voidage was found to increase with an increase in the fines content of the powder and it was only a weak function of the superficial gas velocity. Most importantly, it was found that angular-shaped particles had a higher dense phase voidage, a lower bubble fraction and a lower entrainment rate when compared to spherical-shaped particles having similar particle density and size. Possible reasons for the lower entrainment rate for the angular-shaped particles are given.
The measured dense phase voidage, bubble fraction and entrainment flux was compared with
predictions from published correlations and it was found that none of the correlations provided a good fit to the data obtained in this work and that different correlations predicted widely different entrainment rates for the same system. It is therefore recommended that literature correlations should be used with caution in the absence of experimental data. Empirical correlations for the dense phase voidage and bubble fraction are developed.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.
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Yan, Yong Song, and 嚴永松. "The effect of particle size on the fluidization of geldart B powders in an acoustic field." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/82378265467648314730.
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Silwamba, Marthias. "Investigating particle size segregation in a batch jig." Thesis, 2016. http://hdl.handle.net/10539/20988.
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A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the Degree of Master of Science in Engineering. May, 2016Particle size and size range are among the characteristics that affect the segregation of particles in a jig hence they affect the separation efficiency. The effects of these variables on segregation of particles are not fully understood. This work aimed at contributing to knowledge in this area. To better understand how particle size and size range influence segregation, tests were conducted in which the effects of the density and shape of the particles on segregation were minimized by using as the feed material spherical glass beads of uniform shape and density. Batch experiments of two components systems of various particle sizes were conducted under the same set of jigging conditions: the jigging frequency and jigging time were respectively maintained at 60 cycles per minute and 999 seconds (16.65 minutes). The effect of these operating conditions on segregation was not investigated. At the end of each test run, the jig bed was split into horizontal slices and the composition of each slice was determined. The experimental results showed that below a particle size ratio of 1.50:1, the driving force for the segregation of particles, i.e. the particle size difference, was small hence a low degree of segregation was obtained. The degree of segregation increased above this ratio. However, above the size ratio of 2.00:1, interstitial trickling occurred. With the smaller particles tested (8, 6 and 4mm) poor segregation was observed when the size ratios were of 1.50:1 or less along with what is believed to have been remixing due to convective currents within the jig chamber. It was found that the particle size range had a more pronounced effect on size segregation than the particle size. From the results, it can be said that above a size ratio of about 1.50:1, size segregation is very pronounced. This suggests that density separations of real ores, where both the density and size of particles vary, would be impaired if the particle size range of the material fed to the jig exceeds this ratio. However, this needs further confirmation by testing multiple component systems.
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Cho, SunHee. "Detailed microphysical modeling study of particle size distributions in an industrial plume /." 2005. http://wwwlib.umi.com/cr/yorku/fullcit?pNR11559.
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Thesis (Ph.D.)--York University, 2005. Graduate Programme in Earth and Space Science.Typescript. Includes bibliographical references (leaves 186-196). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11559
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Zhang, Jin. "Formation of secondary organic particulate matter by reactions of gas phase organic compounds with aerosol particles /." 2004. http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss&rft%5Fval%5Ffmt=info:ofi/fmt:kev:mtx:dissertation&rft%5Fdat=xri:pqdiss:MQ99407.
Full textAbstract:
Thesis (M.Sc.)--York University, 2004. Graduate Programme in Chemistry.Typescript. Includes bibliographical references (leaves 117-120). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL:http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss&rft%5Fval%5Ffmt=info:ofi/fmt:kev:mtx:dissertation&rft%5Fdat=xri:pqdiss:MQ99407
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Pretorius, J. H. C. (Jan Hendrik Christoffel). "The influence of PFA particle size on the workability of cementitious pastes." Diss., 2003. http://hdl.handle.net/2263/26113.
Full textAbstract:
In this dissertation the effects of different types of Pulverized Fuel Ash (PF A)-types on the workability of cementitious pastes containing relative large amounts of PF A were investigated. The different types of PF A were produced at the same source thus they were chemically similar but differed in terms of average particle size and size distribution (grading). By using a two-point measurement technique based on flow through a J-shaped tube it was possible to detect relative small differences in workability between pastes. It was found and concluded that the different types of PFA had a significant effect on the workability of pastes containing cement and PFA as well as PF A alone. The physical differences between the PF A-types were quantified and their effects on workability investigated. It was concluded that PF A with a broader particle size distribution range produced pastes with higher workability at constant water content. It was found that compressive strength as measured after 28 days were solely a function of the water/cementitious ratio for the curing regime employed. It was concluded that for curing conditions used the type of PF A used could have a significant effect on compressive strength when constant workability is required.Dissertation (MSc (Transportation))--University of Pretoria, 2006.
Civil Engineering
unrestricted
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Nason, Jeffrey Alan. "Particle aspects of precipitative softening: experimental measurement and mathematical modeling of simultaneous precipitation and flocculation." Thesis, 2006. http://hdl.handle.net/2152/2835.
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Yu, Jiun-Hung, and 余俊宏. "Development of a Multi-Functional Inspection System of Pseudo-Particle Size Analysis and Moisture Determination." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/3b2435.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
95
The aim of this study is to develop a multi-functional instrument of pseudo-particle size analysis and moisture determination. The developed system composes of five major modules, which are materials feeding module, image acquired module, vision procession module, moisture module and control unit. The advantages of this system include total particle size analysis without overlapping or missing of any particles, and also with the moisture determination function, which improved and fastened traditional particle size and moisture determination method The information gathered from the analysis results cover pseudo-particle size distribution, mean size , roundness , sphericity, moisture and uniformity. This is a powerful instrument in any kinds of small particle analysis.
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Huang, Feng-yu, and 黃逢裕. "Development of a Multi-Functional Inspection System for Mixed Coals Particle Size Analysis and Moisture Determination." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/96892884132087394906.
Full textAbstract:
碩士國立臺灣科技大學
機械工程系
98
An on-line optical scanning system with weight measurement device has been developed for mixed coals particle size analysis and moisture determination. Mixed coals particle image is obtained by a line scan CCD camera and analyzed by digital image processing. The developed system is composed of particle separation module, image acquisition module, image processing module, weight measurement module and electronic control module. The main advantage of this system is full inspection (100%) without overlapping or missing of any particles, which improves the area scan charge coupled device (CCD) problems in image acquisition. The particle size distribution, roundness and sphericity of the mixed coals can be obtained by image processing analysis. By measuring weight variation of mixed coals using a load cell before and after heating, the moisture of the mixed coals could be determined. It has been shown that the developed system has a high accuracy, precision, convenience and versatile for some limited size of mixed coals, shape and moisture analysis for the academic and industrial users.
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Chan, Tak Wai. "Application of principal component analysis to atmospheric aerosol size distribution measurements /." 2005. http://wwwlib.umi.com/cr/yorku/fullcit?pNR11557.
Full textAbstract:
Thesis (Ph.D.)--York University, 2005. Graduate Programme in Chemistry.Typescript. Includes bibliographical references (leaves 218-227). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11557
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Grounds, Stephanie Beth. "Mars Exploration Rover (MER) Panoramic Camera (Pancam) Twilight Image Analysis for Determination of Planetary Boundary Layer and Dust Particle Size Parameters." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-12-8635.
Full textAbstract:
How the dust cycle works on Mars is a key atmospheric issue, as the dust cycle is
arguably the dominant cycle in the current Martian climate. In addition, how much is
known about the Martian planetary boundary layer is mostly determined from models
with very little in-situ data from contemporaneous studies to validate such boundary
layer characteristic assumptions, and the model studies have not been able to define a
known height for a possible boundary layer on Mars using ground-based investigations
prior to this research. The Mars Exploration Rovers (MERs), however, show promise in
offering a unique chance to take surface-based measurements to offer support for dust
and boundary layer measurements made from remote sensors. There are three main
objectives of this study: to constrain the late-afternoon maximum height of the boundary
layer for both MER sites, to constrain the mean particle size and variance of the size
distribution in the atmosphere, and to use these results to demonstrate that sunset and
twilight imaging is a useful survey of otherwise difficult-to-determine parameters that
are needed in several tools for studying Mars’ atmosphere.
A modeling approach using twilight-based Sun imaging by the MERs (Sol 1959
for Spirit and Sol 695 for Opportunity) is used to constrain boundary layer and dust
particle size parameters. After determining which parameters control which observables,
resulting elevations and azimuths are matched up to specific observations from the
available MER datasets. A Monte Carlo code produces the model that is then compared
to Sol data with plotting of resulting error. Results include PBL height and structure
estimations and plots along with generalized particle size information for each MER site
on the given Sol. Figures show comparisons of this study’s particle size results with that
of previous studies as well as maps of fit qualities for boundary layer parameters
compared to a contemporaneous modeled scale height estimation. Results show promise
for planning future MER-based campaigns and models.