In this work, digital holography (DH) is extensively utilized to characterize microparticles. Here, “characterization” refers to the determination of a particle’s shape, size, and, in some cases, its surface structure. A variety of microparticles, such as environmental dust, pollen, volcanic ash, clay, and biological samples, are thoroughly analyzed. In this technique, the microscopically fine interference pattern generated by the coherent superposition of an object and a reference wave fields is digitally recorded using an optoelectronic sensor, in the form of a hologram, and the desired particle property is then computationally extracted by performing a numerical reconstruction to form an image of the particle. The objective of this work is to explore, develop, and demonstrate the feasibility of different experimental arrangements to reconstruct the image of various arbitrary-shaped particles. Both forward- and backward-scattering experimental arrangements are constructed and calibrated to quantify the size of several micron-sized particles. The performance and implications of the technique are validated using the National Institute of Standards and Technology (NIST)-traceable borosilicate glass microspheres of various diameters and a Thorlabs resolution plate. After successful validation and calibration of the system, the resolution limit of the experimental setup is estimated, which is ~10 microns. Particles smaller than 10 microns in size could not be imaged well enough to ensure that what appeared like a single particle was not in fact a cluster. The forward- and backward-scattering holograms of different samples are recorded simultaneously and images of the particles are then computationally reconstructed from these recorded holograms. Our results show that the forward- and backward-scattering images yield different information on the particle surface structure and edge roughness, and thus, reveal more information about a particle profile. This suggests that the two image perspectives reveal aspects of the particle structure not available from a more commonly used forward-scattering based image alone. The results of this work could be supportive to insight more on the particles’ morphology and subsequently important for the advancement of contactree particle characterization technique.

Fluidized bed dryers (FBDs) are used in the pharmaceutical industry to remove excess moisture from granule prior to tablet formation. As granule moisture content is reduced from its initial to final state, the velocity required to fully fluidize the granule decreases and the bed voidage decreases. The change in these fluidization properties are attributed to the decrease in the interparticle force load created by a reduction in liquid bridging as moisture is removed. During constant velocity drying, these fluidization properties result in a bubbling fluidization state, which evolves into a bubble coalescing regime as drying proceeds. This behaviour was identifiable using pressure fluctuation time-series analysis techniques.<p> Distributor design studies using dry and wet granule in a conical fluidized bed suggest that the punched plate design limits bubble coalescence when compared to the perforated plate and Dutch weave mesh designs. Furthermore, the Dutch weave results in extensive segregation, which is undesirable from a fluidization perspective. Local drying hydrodynamic measurements using x-ray densitometry found that the punched and perforated plates generate a centralized bubbling core region during drying with a defluidized bed periphery. This fluidized core region grows as drying proceeds until the defluidized region disappears. Under the same operating conditions, a porous plate distributor creates extensive channelling and defluidization across the entire bed cross-section during the constant rate period of drying. These poor fluidization characteristics are a result of the porous plate introducing the gas into the bed as a fine dispersion.<p> Lastly, the hydrodynamics associated with the conical vessel geometry improves the circulation and mixing patterns in fluidized bed dryers. This is especially the case in the entry region of the conical bed where the high inlet gas velocity prevents defluidization around the periphery of the bed. The straight walled geometry of the cylindrical bed resulted in defluidization in this area. As a result, the hydrodynamics associated with bubbling differ significantly between the geometries over the course of drying.

Fluidized bed dryers (FBDs) are used in the pharmaceutical industry to remove excess moisture from granule prior to tablet formation. As granule moisture content is reduced from its initial to final state, the velocity required to fully fluidize the granule decreases and the bed voidage decreases. The change in these fluidization properties are attributed to the decrease in the interparticle force load created by a reduction in liquid bridging as moisture is removed. During constant velocity drying, these fluidization properties result in a bubbling fluidization state, which evolves into a bubble coalescing regime as drying proceeds. This behaviour was identifiable using pressure fluctuation time-series analysis techniques.<p> Distributor design studies using dry and wet granule in a conical fluidized bed suggest that the punched plate design limits bubble coalescence when compared to the perforated plate and Dutch weave mesh designs. Furthermore, the Dutch weave results in extensive segregation, which is undesirable from a fluidization perspective. Local drying hydrodynamic measurements using x-ray densitometry found that the punched and perforated plates generate a centralized bubbling core region during drying with a defluidized bed periphery. This fluidized core region grows as drying proceeds until the defluidized region disappears. Under the same operating conditions, a porous plate distributor creates extensive channelling and defluidization across the entire bed cross-section during the constant rate period of drying. These poor fluidization characteristics are a result of the porous plate introducing the gas into the bed as a fine dispersion.<p> Lastly, the hydrodynamics associated with the conical vessel geometry improves the circulation and mixing patterns in fluidized bed dryers. This is especially the case in the entry region of the conical bed where the high inlet gas velocity prevents defluidization around the periphery of the bed. The straight walled geometry of the cylindrical bed resulted in defluidization in this area. As a result, the hydrodynamics associated with bubbling differ significantly between the geometries over the course of drying.

The physico-chemical characteristics of soymilk particles and the gelation properties of soymilk were investigated as a function of soymilk protein concentration, by preparing soymilk samples from different water-to-bean ratios. Particles from different soymilk protein concentrations showed similar protein composition and surface hydrophobicity, but different -potential, size and protein content. The particle voluminosity was derived using a relation between the effective refractive index of soymilk and the turbidity parameter determined experimentally. For the first time, experimental data was compared to theoretical models, drawing general conclusions about colloidal properties of soymilk particles. Protein concentration and the rate of acidification did not have a significant effect on the acid-induced gelation of soymilk. Results demonstrated that decreased charge is a prerequisite for particle aggregation, which is driven by hydrogen bridging. This thesis provides soymilk processors with general principles on the colloidal behaviour of soymilk, valuable information for new product development and better process design. / Soybean Growers of Ontario, Natural Sciences and Engineering Research Council of Canada

Recent advances in nano technology have opened doors to several next generation devices and sensors. Characterizing nano particles and structures in a simple and effective way is imperative for monitoring and detecting processes at nano scale in a variety of environments. In recent years, the problem of studying nano particle interactions with surface plasmons or evanescent waves has gained significant interest. Here, a numerical model is presented to characterize nano-size particles and agglomerates near a metal or a dielectric interface. The methodology is based on a hybrid method, where the T-matrix approach is coupled with the image theory. The far field scattering patterns of single particles and agglomerates subjected to surface plasmons/evanescent waves are obtained. The approach utilizes the vector spherical harmonics for the incident and scattered fields relating them through a T-matrix. Effects of size, shape and orientation of the cluster on their scattering patterns are studied. An effort is made to distinguish particle characteristics from the scattering information obtained at certain observation angles. Understanding these scattering patterns is critical for the design of sensors using the surface plasmon scattering technique to monitor nano self assembly processes

Increased operations of aircraft, both commercial and military, in hostile desert environments have increased risks of micro-sized particle ingestion into engines. The probability of increased sand and dust ingestion results in increased life cycle costs, in addition to increased potential for performance loss. Thus, abilities to accurately characterize inlet sand would be useful for engine diagnostics and prognostic evaluation. Previous characterization studies were based on particle measurements performed a posteriori. Thus, there exists a need for in situ quantification of ingested particles. The work presented in this thesis describes initial developments of a line-of-sight optical technique to characterize ingested particles at concentrations similar to those experienced by aircraft in brownout conditions using light extinction with the end goal of producing an onboard aircraft diagnostic sensor. By measuring the extinct light intensity in presence of particles over range of concentrations, a relationship between diameters, concentration and light extinction was used for characterization. The particle size distribution was assumed log-normal and size range of interest 1-10 μm. To validate the technique, particle characterization in both static and flow based tests were performed on polystyrene latex spheres of sizes 1.32 μm, 3.9 μm, 5.1 μm, and 7 μm in mono-disperse and poly-disperse mixtures. Results from the static experiments were obtained with a maximum relative error of 11%. Concentrations from the static experiments were obtained with a maximum relative error of 18%. Mono-dispersed and poly-dispersed particle samples were sized in a flow setup, with a maximum relative error of 12% and 10% respectively across all diameter samples tested. Uncertainty in measurements were quantified, with results indicating a maximum error of 17% in diameters due to sources of variability and showed that shorter wavelength lasers provide lower errors in concentration measurements, compared to longer wavelengths. For real time, on-board measurements, where path lengths traveled by light are much larger than distances traveled in initial proof of concept experimental setups, requirements would be to install sensitive detectors and powerful lasers to prevent operation near noise floors of detectors. Vibration effects from the engine can be mitigated by using larger area collection optics to ensure that the transmitted light falls on active detector areas. Results shown in this thesis point towards validity of the light extinction technique to provide real time characterization of ingested particles, and will serve as an impetus to carry out further research using this technique to characterize particles entering aircraft engine inlets. / Master of Science

Interest in non-traditional fuel sources, carbon dioxide sequestration, and cleaner combustion has brought attention on gasification to supplement fossil fueled energy, particularly by a fluidized bed. Developing tools and methods to predict operation and performance of gasifiers will lead to more efficient gasifier designs. This research investigates bed fluidization and particle decomposition for fluidized materials. Experimental methods were developed to model gravimetric and energetic response of thermally decomposing materials. Gravimetric, heat flow, and specific heat data were obtained from a simultaneous thermogravimetric analyzer (DSC/TGA). A method was developed to combine data in an energy balance and determine an optimized heat of decomposition value. This method was effective for modeling simple reactions but not for complex decomposition. Advanced method was developed to model mass loss using kinetic reactions. Kinetic models were expanded to multiple reactions, and an approach was developed to identify suitable multiple reaction mechanisms. A refinement method for improving the fit of kinetic parameters was developed. Multiple reactions were combined with the energy balance, and heats of decomposition determined for each reaction. From this research, this methodology can be extended to describe more complex thermal decomposition. Effects of particle density and diameter on the minimum fluidization velocity were investigated, and results compared to empirical models. Effects of bed mass on pressure drop through fluidized beds were studied. A method was developed to predict hydrodynamic response of binary beds from the response of each particle type and mass. Resulting pressure drops of binary mixtures resembled behavior superposition for individual particles. / Master of Science

Submitted by Andrea Pereira (andrea.pereira@unipampa.edu.br) on 2017-04-10T17:11:21Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) AVALIAÇÃO DA FLUIDODINÂMICA E DO RECOBRIMENTO DE GRÂNULOS DE UREIA EM LEITO DE JORRO PARA MINIMIZAR AS PERDAS DE NITROGÊNIO_ Tamíris Pacheco da Costa.pdf: 4347722 bytes, checksum: 08ea14f09c3f8c19335af29619fc1e37 (MD5) / Approved for entry into archive by Andrea Pereira (andrea.pereira@unipampa.edu.br) on 2017-04-10T17:13:54Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) AVALIAÇÃO DA FLUIDODINÂMICA E DO RECOBRIMENTO DE GRÂNULOS DE UREIA EM LEITO DE JORRO PARA MINIMIZAR AS PERDAS DE NITROGÊNIO_ Tamíris Pacheco da Costa.pdf: 4347722 bytes, checksum: 08ea14f09c3f8c19335af29619fc1e37 (MD5) / Made available in DSpace on 2017-04-10T17:13:54Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) AVALIAÇÃO DA FLUIDODINÂMICA E DO RECOBRIMENTO DE GRÂNULOS DE UREIA EM LEITO DE JORRO PARA MINIMIZAR AS PERDAS DE NITROGÊNIO_ Tamíris Pacheco da Costa.pdf: 4347722 bytes, checksum: 08ea14f09c3f8c19335af29619fc1e37 (MD5) Previous issue date: 2015-06-12 / O papel positivo dos fertilizantes foi comprovado como o fator que, isoladamente, mais contribui para o aumento da produtividade agrícola. O nitrogênio ocupa posição de destaque dentre os elementos essenciais ao desenvolvimento das espécies vegetais, fornecido geralmente através da aplicação da ureia. No entanto, o nitrogênio presente na ureia apresenta alta susceptibilidade à volatilização, que pode chegar a 80 % em algumas condições. Para que haja a minimização destas perdas, o recobrimento da ureia é uma estratégia que vem sendo muito difundida atualmente. Este trabalho teve como objetivo realizar o estudo da fluidodinâmica dos grânulos de ureia em leito de jorro e estudar o processo de recobrimento utilizando uma suspensão polimérica que proporcione uma liberação lenta do nitrogênio presente na ureia. As etapas deste estudo compreenderam: realizar a caracterização física das partículas de ureia; formular e caracterizar uma suspensão que possa ser utilizada no recobrimento de ureia e que seja composta por insumos de baixo custo; caracterizar o filme de recobrimento; estudar a fluidodinâmica das partículas no leito de jorro; utilizar um planejamento experimental fatorial do tipo composto central rotacional para o estudo do recobrimento; avaliar a taxa de liberação de nitrogênio por volatilização; e caracterizar o produto obtido. As variáveis estudadas no planejamento experimental fatorial foram: vazão da suspensão de recobrimento e temperatura do ar de entrada; e como respostas foram avaliadas a eficiência do recobrimento, o crescimento da partícula e a redução da volatilidade do nitrogênio presente na ureia. Os resultados mostraram que o rendimento do recobrimento variou de 17 a 46 %, enquanto o crescimento das partículas ficou entre 0,8 e 4,4 %. O filme de recobrimento proporcionou uma diminuição das perdas por volatilização de nitrogênio para todas as condições do planejamento experimental fatorial, em que o percentual de redução da volatilidade ficou entre de 11 e 50 %. O perfil de liberação do nitrogênio volatilizado durante o período analisado de 14 dias apresentou um pico de volatilização no terceiro dia. Este comportamento foi observado com menos intensidade para a ureia recoberta, demonstrando que o filme de recobrimento foi efetivo no controle da liberação do nitrogênio contido no interior da partícula. As análises obtidas por microscopia demonstraram que o filme de recobrimento envolveu a partícula conforme o esperado. As condições ótimas de temperatura do ar de entrada e vazão da suspensão foram estimadas com base na função desejabilidade. / The positive role of the fertilizers was proven as the factor that alone contributes most to increasing agricultural productivity. The nitrogen occupies a prominent position among the essential elements for the development of the vegetais species, usually provided through the application of urea. However, the nitrogen present in the urea is highly susceptible to volatilization, which can reach 80 % in some conditions. So the minimization of these losses can be performed by the lining of urea, a strategy that has been very utilized today. This work aims to conduct the study of fluid dynamics of urea granules in spouted bed and study the coating process using a polymer suspension that provides a slow release of nitrogen present in the urea. The steps of this study include: performed the physical characterization of urea particles; formulate and characterize a suspension that can be used in the coating of urea and is composed of inexpensive ingredients; characterize the coating film; study the particle fluid dynamics in spouted bed; use a central composite rotational design to coating study; evaluate the nitrogen release rate by volatilization; and characterize the product obtained. The variables studied in the experimental factorial design were: coating suspension flow rate and inlet air temperature; and the responses were evaluated as coating efficiency, particle growth and the volatility of the nitrogen present in the urea. The results showed that the yield obtained for the experimental design was from 17 to 46 %, while the growth of the particles was between 0.8 and 4.4 %. The coating film showed a decrease in nitrogen volatilization losses for all of the experimental factorial conditions, where the volatility reduction percentage was between 11 and 50 %. The release profile of nitrogen volatilized during the analysis period of 14 days presented a peak of volatilization on the third day. This behavior was observed with less intensity for the coated urea, demonstrating that the coating film was effective in controll nitrogen release contained within the particle. The analysis obtained by microscopy demonstrated that coating the film involved the particle as expected. The optimum conditions of inlet air temperature and suspension flow rate were estimated based on the desirability function.

An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to obtain mass spectra of individual aerosol particles in the 0.5 – 2 µm size range in downtown Toronto, Canada for one to two month periods during each season of 2007. A modified version of the Adaptive Resonance Theory (ART-2a) clustering algorithm, which clusters particles based on the similarity of their mass spectra, was shown to be more accurate than the existing algorithm and was used to cluster the ambient data. A total of 21 unique particle types were identified and were characterized based on their chemical composition, their size, and their temporal trends and seasonal variations. Potential sources are also discussed. Particles containing trimethylamine (TMA) were also observed and a more detailed investigation of ambient trends in conjunction with a laboratory experiment was performed in order to elucidate conditions for which TMA will be observed in the particle phase in Southern Ontario.

An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to obtain mass spectra of individual aerosol particles in the 0.5 – 2 µm size range in downtown Toronto, Canada for one to two month periods during each season of 2007. A modified version of the Adaptive Resonance Theory (ART-2a) clustering algorithm, which clusters particles based on the similarity of their mass spectra, was shown to be more accurate than the existing algorithm and was used to cluster the ambient data. A total of 21 unique particle types were identified and were characterized based on their chemical composition, their size, and their temporal trends and seasonal variations. Potential sources are also discussed. Particles containing trimethylamine (TMA) were also observed and a more detailed investigation of ambient trends in conjunction with a laboratory experiment was performed in order to elucidate conditions for which TMA will be observed in the particle phase in Southern Ontario.