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High-rate anaerobic degradation of soluble organic pollutants is becoming very popular, particularly for carbohydrate-based industrial wastewaters. Despite the successes achieved, there are significant limitations in the application of this technology to more complex wastewaters. These are defined as containing other organic compounds such as particulate and soluble proteins and fats, and originate from abattoirs (slaughterhouses), meat and food processing and similar industries. Complex wastewater is often difficult to degrade and components such as solids and fats have slow degradation kinetics and can diminish process performance. Also, the growth of granular sludge, which is critical for optimal performance in upflow reactors, is slow and granule properties such as shear strength and settling velocity are poorer. This is reflected in a lower treatment efficiency of 50%-60% in systems treating complex wastewater compared with efficiencies of 85%-95% in carbohydrate fed treatment systems. This thesis examines specific aspects in the treatment of complex (proteinaceous) wastewater in high rate upflow anaerobic treatment plants and the influences of different conversion processes and microbial characteristics on design and operation. The research problem was approached in two ways: The macroscopic conversion processes were examined by investigating and modelling a two-stage full-scale high rate hybrid reactor in Spearwood, Western Australia, designed and operated by ESI Ltd. This allowed localisation of the key conversion process; specifically hydrolysis of solids, which was found to occur mainly within the methanogenic reactor. Degradation of soluble proteins was rapid and all proteins were fully acidified in the acidogenic (first) stage even at very low retention times. Because of the rapid protein degradation rates, partial acidification, which is often a strategy to improve granulation rates, is incompatible with pH, flow and concentration equalisation. The influence of a protein feed on granulation compared with a carbohydrate feed was examined by sampling granules from the above reactor, as well as two full scale brewery fed reactors and a full scale reactor fed fruit and vegetable cannery wastewater. The cannery fed granules had the highest shear strength and settling characteristics while the protein fed granules had low strength and density , low settling velocity and a comparatively wide size distribution. Both brewery fed granules had very similar and suitable properties. Molecular studies using fluorescent in-situ hybridisation (FISH) probing and microscopy indicated that the granules from the complex (protein) wastewater fed reactor had limited structural characteristics , possibly due to limited reaction rates (as opposed to diffusion rates). Granules from the cannery reactor and both brewery reactors had structures that appeared to be the result of diffusion limitations. Therefore, the critical operational constraints when treating complex wastewater are the particulate biomass and particulate substrate. Awareness of process status could be increased by monitoring of biological and substrate solid inventory in the methanogenic reactor. The model developed in this thesis can greatly assist this. Complications due to particulate substrate and poor granule properties may be intrinsic to complex feeds. These constraints are probably best addressed by design of a methanogenic reactor specifically for complex wastewater. The design should attempt to separate substrate hydrolysis, minimise shear on the granules and retain solids.

Diss. (sammanfattning) Uppsala : Univ., 2005. / Härtill 4 uppsatser.

Thesis (MEng (Metallurgical Engineering))-University of Pretoria, 2008. / Includes bibliographical references.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2013-04-18T18:23:28Z No. of bitstreams: 1 Jamile Gomes Conceição Caracterizaçao clinico...pdf: 1293623 bytes, checksum: 81e290f73ff54554a4e039099727ca5b (MD5) / Made available in DSpace on 2013-04-18T18:23:28Z (GMT). No. of bitstreams: 1 Jamile Gomes Conceição Caracterizaçao clinico...pdf: 1293623 bytes, checksum: 81e290f73ff54554a4e039099727ca5b (MD5) Previous issue date: 2012 / Universidade Federal da Bahia. Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz / Mucoceles são lesões comuns da cavidade oral, causadas por alterações nos ductos excretórios de glândulas salivares menores. A fim de contribuir para um melhor conhecimento do perfil biológico destas lesões, este trabalho teve como objetivo estudar os aspectos clínico-patológicos em uma amostra de mucoceles da boca, bem como componentes celulares como vasos sanguíneos (anti-CD34), mastócitos (triptase de célula mastocitária), macrófagos (anti-CD68) e da matriz extracelular (metaloproteinase de matriz -1 e -9), por meio da técnica imuno-histoquímica. Foram estudados 100 casos de mucocele de extravasamento, o seu conteúdo de fibrose (picrossirius) e 32 casos investigados para as proteínas propostas, adotando-se critérios morfométricos e semiquantitativos. As lesões de mucocele atingiram mais o lábio inferior e a segunda e terceira décadas de vida, com média de 23.2 anos de idade (DP±12,24), sendo os homens mais acometidos pela lesão (56%). O tamanho médio foi de 1,1 cm (DP±0,57). Os vasos sanguíneos CD34 positivos estavam presentes em todos os espécimes (média de 55 microvasos por mm2; DP±0,36), mas a medida que se aproximavam do lúmen cístico pareciam desaparecer. Os mastócitos estavam presentes em todos os casos (média= 7.4; DP±0,12), mais concentrados na região cápsula em torno do tecido de granulação, reduzindo-se neste último. Os macrófagos estavam presentes no tecido de granulação (média= 88; DP±0,52), também em todos os casos, mas especialmente concentrados na superfície luminal e dentro da cavidade cística, sugerindo um importante papel na fagocitose de muco. MMPs apresentaram marcação variável presentes em fibroblastos, células inflamatórias e matriz extracelular, sendo MMP-1 ausente em um caso e a MMP-9 em dois. A fibrose também mostrou-se variável entre os casos. Apesar de existir associação estatística ente macrófagos e MMP1 (p<0.05, Kruskal Wallis), diferença significativa entre os diferentes marcadores não foi encontrada (p> 0.05, Kruskal Wallis). Este estudo contribuiu para o conhecimento dos mucoceles da boca em uma amostra representativa da população da Bahia, destacando que a dinâmica de desenvolvimento de formação dessas lesões envolve migração e interação chaves entre componentes celulares e da matriz extracelular importantes para o remodelamento tecidual dos mucoceles. / Mucoceles are common lesions of the oral cavity, caused by damage to the excretory ducts of salivary glands. The present study investigated a sample of oral mucoceles in our population, to describe their clinical and histopathological features, and to assess cell components such as blood vessels, mast cells, macrophages, and matrix metalloproteinases (MMPs – 1 and -9), using immunohistochemistry, for a better understanding of biological profile of this lesion. Histochemistry using Picrossirius red staining was also included. The sample consisted of 100 oral mucoceles, 32 of which were included for investigating both cell components and MMPs, adopting morphometrical and semi-quantitative criteria. The lesions were located most often on the lower lip and second and third decades of life, with a mean of 23.2 years (SD±12,24). Males had a higher frequency (56%) and mean size of the lesions was 1.1cm ((DP±0,57). CD34-positive blood vessels were present in all specimens (mean, 55 microvessels per mm2), but as they approached the cystic lumen seemed to disappear. Mast cells were present in all cases (mean= 7.4; SD±0,12) and concentrated in the capsule surrounding the granulation tissue, although they were reduced in the latter. The macrophages were present in the granulation tissue (mean=88; SD±0.52), also in all cases, but they were especially concentrated on the luminal surface and within the cystic cavity, indicating a pivotal role in phagocytosis of mucus. MMPs showed variable immunostaining and were found in fibroblast and inflammatory cells, however, they were absent in one case of MMP1 and two cases of MMP9. Fibrosis was also variable in all of specimens. Although there was a statistical association between macrophages and MMP1 (P<0.05, Kruskal Wallis), significant difference between the different markers was not found (P<0.05, Kruskal Wallis). This study provides an important insight to the knowledge of oral mucoceles from a sample from Salvador, Bahia, Brazil. Furthermore, it highlights that the development dynamic of these lesions involves migration and interaction of key cellular and extracellular matrix components which are essential to the tissue remodeling of oral mucoceles.

This thesis concerns the construction of a detailed, compartmental population balance model for twin-screw granulation using the stochastic weighted particle method. A number of new particle mechanisms are introduced and existing mechanisms augmented including immersion nucleation, coagulation, breakage, consolidation, liquid penetration, primary particle layering and transport. The model’s predictive power is assessed over a range of liquid-solid mass feed ratios using existing experimental data and is demonstrated to qualitatively capture key experimental trends in the physical characteristic of the granular product. As part of the model development process, a number of numerical techniques for the stochastic weighed method are constructed in order to efficiently solve the population balance model. This includes a new stochastic implementation of the immersion nucleation mechanism and a variable weighted inception algorithm that dramatically reduces the number of computational particles (and hence computational power) required to solve the model. Optimum operating values for free numerical parameters and the general convergence properties of the complete simulation algorithm are investigated in depth. The model is further refined though the use of distinct primary particle and aggregate population balances, which are coupled to simulate the complete granular system. The nature of this coupling permits the inclusion of otherwise computational prohibitive mechanisms, such as primary particle layering, into the process description. A new methodology for assigning representative residence times to simulation compartments, based on screw geometry, is presented. This residence time methodology is used in conjunction with the coupled population balance framework to model twin-screw systems with a number of different screw configurations. The refined model is shown to capture key trends attributed to screw element geometry, in particular, the ability of kneading elements to distribute liquid across the granular mass.

<p>  </p> <p>This dissertation investigated the influence of formulation and process design on the internal density structure and nutrient release of urea fertilizer as an alternate route to overcome nutrient leaching problems. The first part of the work focused on producing urea composites with different binders to optimize the formulation and composite microstructure. The second part of the study compared the microstructure and release kinetics of dry compacted and bilayer urea granules. Finally, the third part determined nitrate and ammonium leaching using disturbed soil column experiments. The optimization of granule microstructure and formulation design developed in this work yielded a 97.5 % reduction in the initial dissolution rate of modified urea granules compared to conventional urea fertilizer. Thus, the development of processing platforms focused on granule internal density distributions demonstrated a fundamental contribution to optimizing nutrient release properties.</p>

Melt granulation is a versatile process that is underutilized in the pharmaceutical industry. Most pharmaceutical wet granulation and twin-screw extruders can be adapted for melt granulation. Twin-screw melt granulation (TSMG) is of interest since is a continuous process and allows for flexible process design and a high degree of control. TSMG can be used to produce formulations for oral immediate or sustained release. This research focuses on the use of TSMG to taste-mask APIs. Many APIs are bitter or unpleasant tasting. Taste-masking may be required, particularly for products intended for pediatric patients. Taste-masking has been achieved with many different techniques, but a simple, cost-effective method that can be applied to many different APIs is not currently available. A matrix encapsulation approach using continuous twin-screw melt granulation was attempted with three different APIs. The resulting granule properties, particularly particle size, are related to the granulation process parameters. Prediction of taste-masking based on in vitro assessments is challenging and generally clinical evaluation is required. A small-volume dissolution method was developed as a screening test the melt granules. It is not clear if this technique is predictive of clinical taste-masking performance, but it is expected to be an improvement over discrete sampling or typical quality control dissolution methods. The dissolution rate was estimated using the Noyes-Whitney equation and correlated to the mean granule particle size. From this, a simple model for time to a taste threshold could be used to define a design space around the granulation process. / Pharmaceutical Sciences

El ritmo de aplicación de los procesos que manejan sólidos particulados ha crecido significativamente. Sin embargo, la complejidad de los fenómenos físicos/químicos que tienen lu-gar ha limitado la mejora continua de los mismos. Por ejemplo, las plantas de granulación (industrias cuyos procesos aumen-tan el tamaño de partículas) distan de operar bajo condicio-nes óptimas, presentando frecuentes problemas operativos y paradas indeseadas. A menudo los desafíos operativos se re-suelven por prueba y error, en lugar de ser enfrentados utili-zando principios científicos. Considerando que la urea es el fer-tilizante nitrogenado más usado, que la tecnología líder para su producción es la granulación en lechos fluidizados y que existe una falta de entendimiento de los principios fundamen-tales que gobiernan la operación de plantas de granulación, esta Tesis se centra en el desarrollo de herramientas matemá-ticas que permitan la operación eficiente de circuitos de gra-nulación de fertilizantes. En particular, el circuito de granula-ción de urea bajo estudio está constituido por: una unidad central de granulación (lecho fluidizado multicámaras) donde se produce el crecimiento de las partículas, un enfriador aguas abajo; una zaranda de clasificación que separa (median-te el uso de dos mallas de diferentes aperturas) la corriente de salida del enfriador en material en especificación (produc-to), material de tamaño mayor que el deseado (gruesos) y ma-terial más fino que el producto (finos); y un molino de rodillos (constituido por dos pares de rodillos) que reduce el tamaño de los gruesos para ser reciclados al granulador junto con los finos provenientes de la zaranda. En primer lugar se presentan los modelos correspondientes al molino de rodillos y la zaranda vibratoria. Los parámetros involucrados en los modelos son ajustados a partir de datos experimentales disponibles de una planta de granulación de urea de alta capacidad. En cuanto al granulador, se implementa un modelo desarrollado previamente en nuestro grupo de investigación. Por su parte, en esta Tesis se desarrolla el modelo de un enfriador de lecho fluidizado ba-sado en el modelo del equipo de granulación. Luego de haber validado los modelos que presentan parámetros de ajuste usando información experimental, se presenta un simulador completo del circuito de granulación de urea. El mismo resulta de la integración de los modelos de todos los equipos descrip-tos anteriormente y de la implementación de la corriente de reciclo (de material fuera de especificación) que ingresa al granulador. Una vez que se verifica la capacidad del simulador para reproducir los datos industriales disponibles, se realiza un análisis de sensibilidad donde se determinan las variables operativas y/o de diseño que más afectan la performance del circuito. El análisis dinámico de respuesta a lazo abierto del sistema ante diversas perturbaciones refleja que la dinámica de este tipo de circuitos resulta extremadamente compleja de predecir sin contar con un simulador que facilite esta tarea. Para finalizar, se analizan diversos casos de optimización de estado estacionario relevantes para la práctica industrial, con el objeto de encontrar nuevos puntos operativos manipulando variables operativas y/o de diseño. Considerando que la diná-mica de los circuitos de granulación suele ser oscilante en el tiempo a causa del reciclo, también se postulan optimizacio-nes dinámicas formuladas como problemas de control óptimo. Este último estudio resulta de utilidad para identificar los cuellos de botella que limitan, en particular, los aumentos de capacidad de planta y para analizar posibles acciones ten-dientes a superarlos. En síntesis, en esta Tesis se desarrolla un simulador dinámico que permite representar la operación de un circuito de granulación de urea de manera apropiada, ofreciendo un recurso en condiciones de ser aplicado para múltiples propósitos: evaluar cambios de diseño o diagrama de flujo, ser usado como herramienta de capacitación, valorar el efecto de diferentes perturbaciones, estudiar distintos escenarios a lazo abierto o cerrado, etc. / Studies about particle technology have grown significantly during the last years. However, the complexity of the involved physical/chemical phenomena has limited the improvement of the processes that handle particulate solids. For example, granulation plants (i.e., industries dedicated to the particles size enlargement) operate far from optimal conditions, with frequent operating problems and plant shutdowns. The opera-ting challenges are often overcome by trial and error instead of being solved by means of scientific principles. Taking into account that urea is the most widely used nitrogen based fertilizer, fluidized bed granulation is the leading technology for its production and that there is a lack of understanding of the fundamental principles governing the operation of granu-lation plants, this Thesis focuses on the development of mathematical tools to allow the efficient operation of fertilizer granulation circuits. In particular, the urea granulation circuit under study includes: a central granulation unit (multichamber fluidized bed) where particles growth takes place; a fluidized-bed cooler downstream the granulator; a double-deck vibra-ting screen (using two decks of different mesh openings) that separates the material that leaves the cooler into particles on specification (product), material bigger (oversize) and smaller (fines) than the desired product size; and a double-roll crusher that reduces the size of oversize particles which are recycled to the granulator together with the fines classified by the screen. The mathematical models for the crusher and screen are first presented. The required model parameters are fitted considering experimental data available from a high capacity urea plant. Regarding the granulation unit, a model previously developed in our research group is used. In this Thesis, the fluidized bed cooler model is developed based on its similarity with the granulator mathematical representation. After proving the good capability of the individual models to represent experimental trends adequately, a simulator for the complete urea granulation circuit is presented. This is achie-ved by integrating the previously described models and by solving the recycle stream (off-specification material) that enters the granulator. Once the simulator ability to track the particle size distributions of the circuit solids streams is verified, a steady-state sensitivity analysis is performed in order to determine the operating and/or design variables that most affect the circuit performance. The non steady-state analysis, i.e. the study of the open-loop circuit behavior sub-ject to different disturbances, indicates that the granulation circuit dynamics is extremely complex to be predicted without a simulator that facilitates this task. Finally, several steady-state optimization cases, relevant to the industrial practice, are studied with the aim of finding new operating points by manipulation of operating and/or design variables. Considering that granulation circuits usually present an oscillating behavior due to the recycle stream, dynamic optimizations formulated as optimal control problems are also performed. This latest study is useful not only to identify the bottlenecks that limit, for example, increments in plant capacity but also to analyze possible actions to overcome them. In summary, in this The-sis, a dynamic simulator to properly represent the opera-tion of a urea granulation circuit is developed, providing a multi-task tool. In fact the simulator can be used to explore design changes or flowsheet variations, as a training tool, for evalua-ting the effect of different disturbances, to study different open or closed loop operations, etc.

Granulation is an important process for industries ranging from plastics to food and pharmaceutics. In the last decades, the twin-screw extruder has been more and more studied as a continuous method for granulation. But there are many questions remaining to be answered such as the functions of kneading block and the granulation behavior in this zone, the influence of the wetting method, and also the influence of the active pharmaceutical ingredient (API) properties on the granulation process. Therefore, in this project, a series of experiments were performed based on a new technique to the granulation field named ‘screw pullout’ for understanding the granulation process within the twin-screw extruder. In order to understand the specific function of an important screw element known as a kneading block, the physical particle motion reflecting progress of granulation was monitored along the screw. Different feed rate and formulations were studied; the residence time and pressure in kneading block were measured; and the granules along the screw were characterized for their porosity and size distribution. It was found that granule consolidation and breakup within the kneading block allowed the production of granules with consistent properties and excellent mechanical strength. However, the changes produced by a kneading block are dependent upon the formulation. For example, the kneading block demonstrates no observable function with formulations containing a significant content of microcrystalline cellulose. The most notable benefit of the kneading block to all tested materials appeared to be distribution of the interstitial binding liquid rather than to compact the powders. A new wetting method using a foam binder has been studied intensively in this work to assess its influence on the granulation process. A series of studies have been performed to compare the granule development along the screws as powder formulation and screw design were varied to test for the differences induced by the two wetting methods (foam delivery or liquid injection). The evolution of the granules along the screw was characterized by analyzing the particles size distribution, porosity, and fracture strength. It was found that the wetting method had minor impact on the particle size distribution due to the strong mechanical dispersion inherent to the extruder. The major finding for the pharmaceutical industry was that the foam method reduces the required amount of liquid to granulate, thereby dropping drying time after the process. The foamed binder was also found to be preferred when the formulation contains powder components with poor spreading properties. Finally, the influence of an API’s physical properties on granulation was studied by comparing formulations with varying API hydrophobicity. It was found that the API and binder distribution was not affected by the hydrophilicity of API, while the particle size distribution, porosity and fracture strength were strongly dependent on the properties of the API. / Thesis / Master of Applied Science (MASc)