Résumé : Depuis le début du XXe siècle, la production de bétons secs représente une industrie importante pour le développement des infrastructures en bétons compactés au rouleau notamment pour la construction de barrages, de digues, de pavages, et les bétons moulés à sec pour la pré-fabrication de blocs de maçonnerie, de briques, de pierres de pavé, etc. La durabilité de celles-ci peut être améliorée en réduisant leur consommation de ciment Portland et de granulats naturels en utilisant, respectivement, des ajouts cimentaires et des matériaux granulaires alternatifs. D’ailleurs, beaucoup de sous-produits industriels et autres ajouts cimentaires alternatifs ne respectant pas les exigences pour le béton conventionnel ont été utilisés avec succès dans ce type de béton. Les cendres de biomasse sont des sous-produits prometteurs pour les applications de bétons secs. Ces cendres sont obtenues dans une centrale de cogénération de l’industrie des pâtes et papiers suite à la combustion de leurs boues de traitement des eaux usées, de leurs boues de désencrage, et autres résidus de bois. Les cendres volantes de biomasse (CVB) ont une finesse similaire à celle du ciment et elles possèdent aussi un potentiel de réactivité pouzzolanique. Elles peuvent donc remplacer une partie du ciment utilisé dans la formulation de bétons. Les cendres grossières de biomasse (CGB) ont une granulométrie voisine de celle d’un sable fin. Elles peuvent donc être valorisées en remplaçant une partie des granulats naturels utilisés dans les formulations de bétons. Bien que les propriétés physico-chimiques et les interactions cimentaires de celles-ci soient étudiées depuis le début des années 2000, très peu d’applications commerciales ou industrielles ont été développées. Ce projet de recherche vise l’étude et l'optimisation des CVB comme ajout cimentaire alternatif et des CGB comme granulats fins alternatifs dans la production de bétons compactés au rouleau (BCR) et à la paveuse (BCP) pour des applications de pavages industriels et dans la production de bétons moulés à sec (BMS) pour des applications de préfabrication de pierres de pavé. Pour chacune de ces applications, des formulations incorporant un taux de substitution jusqu'à 30% du ciment par des cendres volantes et jusqu’à 100% du sable par des cendres grossières ont été réalisées. Ces travaux d’optimisation ont été effectués avec des bétons à rap-port eau-liant de 0,32, 0,35 et 0,37. Les propriétés à l’état frais (maniabilité et consistance), à l’état durci (résistance à la compression, à la flexion et à la traction), et de durabilités (absorption à l’eau, vides perméables et résistivité électrique) jusqu'à 91 jours ont été mesurées pour tous les mélanges de béton. Le rapport eau-liant, la teneur en pâte et les taux de remplacement optimaux ont également été combinés et optimisés afin de valoriser un maximum de cendres de biomasse, volantes et grossières, dans une seule formulation. Les résultats des mélanges de BCR fabriqués en laboratoire avec 10% et 20% de CVB et combinés à 50% de CGB ont respectivement montré des maniabilités désirées et des résistances à la flexion supérieures aux limites prescrites par les devis techniques pour une utilisation pratique de 23% et 29%. Ces deux mélanges donc ont été sélectionnés pour évaluer leur comportement in situ à l’aide de la construction d'une dalle de stockage de 792 m² par 300 mm d'épaisseur à l'aide de pratiques courantes. Des carottes ont été prélevées dans la dalle à 28 et 308 jours. La résistance à la compression des noyaux à l'âge de 308 jours a atteint 33 et 30 MPa pour les deux mélanges testés, respectivement. Les BMS fabriqués avec 5%, 10%, ou 15% CVB et 25% de CGB peuvent atteindre un indice de compaction de 99% avec un travail de compaction inférieur à celui spécifié par les fabricants de pierre de pavés. L'utilisation des CVB et CGB entraîne une faible diminution de la résistance à la compression, mais présente des valeurs de perméabilité et d’absorption à l’eau très faibles et inférieures aux exigences requises les normes (près de 5%). Ces travaux de recherche présentent un débouché potentiel à la valorisation des cendres volantes et grossières de biomasse issues de l’industrie des pâtes et papiers dans les bétons secs comme ajout cimentaires ou granulats fins. Cette approche peut offrir une contribution significative pour la réduction des émissions de gaz à effet de serre associés à la production de ce type de béton et dans les gestions des matières résiduelles de l’industrie des pâtes et papiers. / Abstract : Since the early twentieth century, the production of dry concrete is an important industry for infrastructure development including the construction of dams, core dikes, and pavements using roller-compacted concrete, and precast masonry blocks, bricks, pavers using dry-cast concrete. The sustainability thereof can be improved by reducing its consumption of Portland cement and natural aggregates using cementitious supplementary cementitious materials and alternative granular materials, respectively. Moreover, many industrial by-products and other mineral additions not meeting the requirements for conventional concrete have been success-fully used in such concrete. The biomass ashes are promising supplementary materials for dry concrete applications. These ashes are produced in a cogeneration plant of the pulp and paper industry following the burn-ing of their wastewater treatment sludge, their de-inking sludge, and other wood residues. The biomass fly ash (BFA) have a similar finesse in the cement and they also have a potential poz-zolanic reactivity. They may therefore replace part of the cement used in concrete formula-tions. The biomass bottom ashes (BBA) have a particle size close to that of a fine sand. They can be use to replace a portion of the natural aggregates. Although the physicochemical proper-ties and interactions with cement have been studied since the early 2000s, very few commer-cial or industrial applications have been developed. This research project aims at studying and optimizing the BFA content as an alternative sup-plementary cementitious materials and the BBA content as an alternative fine aggregates in the production of roller-(RCC) and paver-compacted concrete (PCC) for industrial pavements and dry-cast concrete (DCC) for the manufacture of pavers. Formulations incorporating substitu-tion rates of cement up to 30% by BFA and of the sand up to 100% by BBA were evaluated for each of the mentioned applications. This optimization work was carried out with concrete water-to-binder ratio (w/b) of 0.32, 0.35 and 0.37. The fresh properties (workability and com-pactness), hardened properties (compressive strength, flexural strength and splitting-tensile strength) and transport properties (water absorption, permeable voids and electrical resistivity) up to 91 days were measured for all concrete mixtures. The optimal w/b, paste content and replacement rates were also combined and optimized in order to maximize the biomass fly and bottom ashes content, in a single formulation. The results of concrete mixtures made with 10% and 20% BFA with 50% BBA showed 23% and 29% higher flexural strength than the limits required for practical use of RCC, respective-ly. These two RCC mixtures were selected for the assessment of in situ behaviors through the construction of a storage slab of 792 m² per 300 mm thick using standard practices. Core sam-ples were cut from the slabs at age of 28 and 308 days for follow-up of the concrete behavior with time. The compressive strength of the cores at an age of 308 days reached 33 and 30 MPa for the two tested mixtures, respectively. The DCC mixtures made with 5%, 10%, or 15% BFA and 25% of BBA can reach a compact-ness index of 99% with a compaction work lower than specified by the Standards. The use of the BFA and BBA lead to small decrease of the compressive strength, however they can result in very low permeability and water absorption values lower than required by the specifications (close to 5%). This research presents a potential market for recycling biomass fly and bottom ashes from the pulp and paper industry in dry concrete as alternative supplementary cementitious materials or fine aggregates. This approach can provide a significant contribution to reduce greenhouse gas emissions associated with the production of this type of concrete and with the managements of by-products from the pulp and paper industry.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2005. / 192 leaves on CD format, preliminary i-xii pages and numbered pages 1-135. Includes bibliography, list of figures and tables. / ENGLISH ABSTRACT: As a fibre reinforced material, engineered cementitious composite (ECC) has tough, strain-hardening behaviour in tension despite containing low volumes of fibres. This property can be brought about by developments in fibre, matrix and interfacial properties. Poly Vinyl Alcohol (PVA) fibre has been developed in recent years for ECC, due to its high tensile strength and elasticity modulus. However, the strong interfacial bond between fibre surface and matrix is a challenge for its application. This study focuses on the tailoring of matrix and fibre/matrix interfacial properties by cement replacement with fly ash (FA) and Ground Granulated Corex Slagment (GGCS). In this study the direct tensile test, three point bending test, micro-scale analysis, such as X-Ray Fluorescence Spectrometry analysis (XRF), Scanning Electron Microscope (SEM), are employed to investigate the influence of cement replacement, aging, Water/Binder (W/B) ratio, workability on ECC behaviour. This study has successfully achieved the aim that cement replacement by FA and GGCS helps to improve the fibre/matrix interfacial properties and therefore enhances the ECC tensile behaviour. Specifically, a high volume FA-ECC has stable high tensile strain capacity at the age of 21 days. This enables a constant matrix design for the investigation of other matrix influences. The Slag-ECC has a higher tensile strength but lower tensile strain capacity. The combination of FA and GGCS, moderate tensile strength and strain capacity is achieved Both tensile tests and Micro-scale analyses infer that the high volume FA-ECC has an adhesive type fibre/matrix interfacial interaction, as opposed to the cohesive type of normal PVA fibre-ECC. The different tensile behaviour trend of steel fibre-ECC and PVA fibre-ECC with the FA content is presented and discussed in this research. The investigations of aging influence indicate that the high volume FA-ECC has a beneficial effect on the properties of the composite at an early stage. However, at a high age, it has some difficulty to undergo multiple cracking and then leads to the reduction of tensile strain capacity. The modified mix design is made with the combination of FA and GGCS, which successfully increases the interfacial bond and, thereby, improves the shear transfer to reach the matrix crack strength. Therefore, an improved high age tensile behaviour is achieved. The W/B and fresh state workability influence investigations show that the W/B can hardly affect the tensile strain at early age. However, the workability influences on composite tensile strain significantly, because of the influence on fibre dispersion. Other investigations with regard to the hybrid fibre influences, the comparison of bending behaviours between extruded plate and cast plate, the relation between bending MOR and tensile stress, and the relation between compression strength and tensile strength contribute to understand ECC behaviour. / AFRIKAANSE OPSOMMING: As ‘n veselversterkte materiaal, het ontwerpte sementbasis saamgestelde materiale, taai vervormingsverhardingseienskappe in trek, ten spyte van lae veselinhoud. Hierdie eienskap word bewerkstellig, deur ontwikkelings in vesel, matriks en tussenveselbindingseienskappe. Poli-Viniel Alkohol (PVA) vesels is ontwikkel vir ECC, as gevolg van die hoë trekkrag en hoë modulus van hierdie veseltipe. Die sterk binding tussen die PVA-veseloppervlak en die matriks is egter ‘n uitdaging vir sy toepassing. Hierdie studie fokus op die skep van gunstige matriks en vesel/matriks tussenvesel-bindingseienskappe deur sement te vervang met vlieg-as (FA) en slagment (GGCS).In hierdie navorsing is direkte trek-toetse, drie-punt-buigtoetse, mikro-skaal analise (soos die X-straal ‘Fluorescence Spectrometry’ analise (XRF) en Skanderende Elektron Mikroskoop (SEM))toegepas. Hierdie metodes is gebruik om die invloed van sementvervanging,veroudering, water/binder (W/B)-verhouding en werkbaarheid op die meganiese gedrag van ECC te ondersoek.Die resultate van hierdie navorsing toon dat sementvervanging deur FA en GGCS help om die vesel/matriks tussenveselbindingseienskappe te verbeter. Dus is die ECC-trekgedrag ook verbeter. Veral ‘n hoë volume FA-ECC het stabiele hoë trekvervormingskapasiteit op ‘n ouderdom van 21 dae. Dit bewerkstellig ‘n konstante matriksontwerp vir die navorsing van ander matriks invloede. Die Slag-ECC het ‘n hoër treksterkte, maar laer trekvervormingskapasiteit. Deur die kombinasie van FA en GGCS word hoë treksterkte, sowel as gematigde vervormbaarheid in trek verkry. Beide trektoetse en mikro-skaal analise dui aan dat die hoë volume FA-ECC ‘n adhesie-tipe vesel/matriks tussenvesel-bindingsinteraksie het, teenoor die ‘kohesie-tipe van normale PVA vesel-ECC. Die verskille in trekgedrag van staalvesel-ECC en PVA vesel-ECC ten opsigte van die FA-inhoud is ondersoek en word bespreek in die navorsing. Die navorsing toon verder dat die hoë volume FA-ECC goeie meganiese eienskappe het op ‘n vroeë ouderdom. Op hoër ouderdom word minder krake gevorm, wat ‘n verlaging in die trekvervormingskapasiteit tot gevolg het. Met die kombinasie van FA en GGCS, word die vesel-matriksverband verhoog, waardeur ‘n verbetering in die skuifoordrag tussen vesel en matriks plaasvind. Verbeterde hoë omeganiese gedrag word daardeur tot stand gebring. Navorsing ten opsigte van die invoed van die W/B en werkbaarheid dui daarop dat die W/B slegs geringe invloed het op die trekvormbaarheid, terwyl die werkbaarheid ‘n dominerende rol speel in hierdie verband.Verdere studies sluit in die invloed van verskillende vesels, die vergelyking van die buigingsgedrag van geëkstueerde plate en gegote plate, die verhouding tussen buigsterkte en treksterkte, en die verhouding tussen druksterkte en treksterkte dra by tot beter begrip van die gedrag van ECC.

The genus Restrepia is well known to orchid enthusiasts but its micromorphology has not been described, and its pollination and breeding systems have not been investigated. The aim of this investigation was, therefore, to add to existing knowledge so that the resultant data could be used to facilitate ex situ conservation initiatives. A detailed electron microscopy study (SEM) of the floral organs was performed. This confirmed the structure of the dorsal sepal and lateral petal osmophores, their secretory nature together with that of the synsepal and the labellum. It was postulated how, by manipulating different labellar surface textures, the flower might use these ‘tactile guides’ to steer the insect (fly) through the flower. The cirrhi were postulated to help by destabilising the pollinator in flight, trapping it and bringing about pollination. The papillate structure of the calli was established and their optical properties investigated. Media comparison investigations established that Western medium supported the highest germination rates and, with the addition of banana supplement, the highest rates for seedling growth and development. This represented the first protocol for axenic germination of Restrepia in the literature (Millner et al., 2008) and provided a tested methodology for investigating breeding systems and producing Restrepia plant material for both scientific and horticultural purposes. Self-pollinations were found to produce fewer embryos compared to cross-pollinations. The operation of self-incompatibility (SI) was confirmed by the study of pollen tube growth which further confirmed the time interval between pollination and fertilisation. A time line from pollination/fertilisation to flowering was established. The type of SI in operation was best explained by gametophytic incompatibility. This demonstrated that it was possible to raise Restrepia hybrids and species from seed, by performing intraspecific crosses so helping to preserve them for posterity and relieve pressure on wild populations. Narrow endemic Restrepia species face combined threats from habitat loss, habitat degradation and problems of viable seed production due to the effects of SI and inbreeding depression (ID). Recently developed online resources, such as GeoCAT, were used to perform a Red List assessment in order to identify the degree of threat individual species faced, both globally and nationally. All species were classified as facing substantial levels of threat; although this was lessened for populations in protected habitats. Conservation is needed for cultivated collections as well as these wild populations by keeping alive existing knowledge and expertise in growing these species.

This thesis describes an investigation into the effects of habitat composition, principally the composition of algae in a wrack bed, on the life history of the seaweed fly, Coelopa frigida. The mating system of C. frigida is dominated by intense sexual conflict characterised by frequent harassment by males leading to a vigorous pre-mating struggle. This response leads to sexual selection for large male size and sexual dimorphism. The mating behaviour of C. frigida is affected by their environment, with exposure to brown algae inducing harassment in males and oviposition in females. Despite more than two decades of research into coelopid reproduction little is known about how habitat composition alters the patterns and processes of sexual conflict. Studies contained in this thesis consider environmental influences that both directly and indirectly influence sexual conflict. Direct effects of the environment are measured by conducting mating trials following culture of C. frigida on different species of algae and by exposing males to different species of algae. This work is accompanied by studies of larval development and adult survival on different algae. In recent years it has been observed that the distribution of European coelopids has undergone a northward range shift. An investigation into the current distribution of European coelopid species and a discussion of the effects of climate change that may have caused this change is included. Finally, the use of stable isotope analysis to determine the diet of wild coelopids and alternative statistical methods to analyse mating trials are described.

This master thesis presents the effects of fly ash on the properties of alkali activated slag concrete, commonly referred as Geopolymer concrete (GPC). Cement manufacturer are major producers of CO2 which negatively affects the environment. Due to the increased construction activities and environmental concern, it is necessary to introduce alternative and eco-friendly binders for concrete. Slag and fly ash based concrete, which is by-product from industrial waste, is probably the best replacement for OPC concrete due to less or nil environmental issue. Most of the researchers have already concluded that slag and fly ash can be used as binders in concrete by activating them with alkali activator solution (e.g. by sodium silicate or sodium carbonate). In the present work concretes were produced by varying the proportion of slag to fly ash (40:60, 50:50, 60:40 & 80:20); amount of alkali activators (5, 10 & 14) and chemical modulus of sodium silicate (Ms) (0.25, 0.5 & 1).  Setting times and compressive strength values were evaluated. Results showed that decrease in fly ash content irrespective of % of alkali activators and alkali modulus (Ms), the compressive strength was increasing and setting time was getting shorter. The produced concretes showed increasing compressive strength with increase in % of alkali activator for Ms 0.5 and 1, while for Ms=0.25 the strength was decreasing with increase in % of alkali activators. From this it can be concluded that, Ms=0.5 was the optimum point below which the reaction got slower. Based on the initial investigations, mix S8:F2-SS10(1) and S8:F2-SS10(0.5) showed most promising results in terms of fresh and hardened concrete properties and were easy to handle. Consequently, the above mentioned mixture was chosen to be studied in more detail. The experimental program for these mixes included determination of slump flow, compressive strength (7, 14, 28 days) and shrinkage (drying and autogenous). The results shows that, strength increased with time and comparatively mix with Ms=0.5 showed higher compressive strength than mix with Ms=1, due to higher alkalinity of the pore solution. Mix with Ms=1 showed higher drying shrinkage compared to mix with Ms=0.5, which was explained by higher alkalinity of the solutions (Ms=0.5) leading to rapid formation of aluminosilicate gel. Autogenous shrinkage appeared to be higher for mix with Ms=0.5. This was associated with lower modulus which leads to densification of concrete microstructure at early ages. Pore diameter decrease and the water trapped in the pores exerted increasing tensile stress resulting for higher autogenous shrinkage.

Cementproduktion står idag för totalt 5 % av koldioxidutsläppen globalt, vilket t.ex. är mer än dubbelt så mycket som den globala flygindustrin. Nya cement- och betongrecept, med nya egenskaper, utvecklas med målet att minska klimatbelastningen. I produkten Bascement ersätts delar av klimatbelastande cementklinker med mineraltillsatsen flygaska, en restprodukt från andra industrier. Detta ska alltså leda till en minskad klimatbelastning. Betong med Bascement har dock orsakat förseningar och extra kostnader i produktion på grund av långa torktider som inte stämt överens med simuleringar i TorkaS 3.2, en programvara baserad på betong med Byggcement. TorkaS ska ersättas av programvaran Produktionsplanering Betong (PPB) som kan simulera uttorkning i betong med Bascement. Målet med studien är att undersöka hur fuktsimuleringar i PPB skiljer sig jämfört med genomförda fuktmätningar i fyra betongprover med två olika vattencementtal, vct. Genom att förvara proverna i olika miljö är målet att experimentellt mäta hur omgivningen påverkar uttorkningen. Målet är vidare att visa skillnader mellan fuktsimuleringar med inbyggd klimatdata i PPB och med egna uppmätta klimatdata. Resultaten från de experimentella undersökningarna visar att uttorkningen blev större i betongprover med vct 0,40 än för motsvarande prover med vct 0,55 efter 70 dagar. Prover som hade förvarats i en stabil inomhusmiljö hade torkat mer än prover som hade förvarats i en varierande utomhusmiljö, vilket i denna studie inte stämde överens med simuleringar i PPB. Resultatet i denna studie visar att simuleringar i PPB tenderar att visa något större uttorkning jämfört med genomförda fuktmätningar. Denna överskattning blir större vid simuleringar med en varierande utomhusmiljö än med en stabil inomhusmiljö. Överskattningen blir större vid simuleringar med inbyggd klimatdata i PPB än med egna uppmätta klimatdata. Vid justering av betongens maxtemperatur i PPB till verkligt uppmätt maxtemperatur påverkas fuktsimuleringarna positivt så att de närmar sig de experimentellt erhållna resultaten. Betong med låga vct påverkas mer av en sådan justering än höga vct. Slutsatsen i denna studie är baserad på simuleringar och fuktmätningar i ett fåtal betongprover, vilka kan ha utsatts för störningar. Fler studier behövs för att validera reliabiliteten hos programvaran PPB. Val av härdningsmetod samt maxtemperatur under härdning kan påverka uttorkningen och simuleringar i PPB. Experimenten indikerar att simuleringar med PPB tenderar att avvika om betong med höga vct utsätts för vattentillskott kort efter gjutning. Korrekt maxtemperatur i PPB är viktigt för en mer verklig simulering av uttorkning i betong, särskilt vid låga vct. Simuleringar i PPB tenderar att bli mer korrekta med egna klimatdata än med inbyggd klimatdata. / Cement production currently accounts for a total of 5 % of carbon dioxide emissions globally, which for example is more than twice as much as the global aviation industry. New cement and concrete recipes, with new properties, are being developed with the aim of reducing the climate load. In the Portland fly ash cement, parts of climate-stressing cement clinkers are replaced with the mineral-added fly ash, a residual product from other industries. This should lead to a reduced climate impact. Concrete with Portland fly ash cement, however, has caused delays and extra costs in production due to long drying times that did not match with simulations in the software TorkaS 3.2, which is based on concrete with Portland-limestone cement. TorkaS will be replaced by the software Production Planning Concrete, PPB, which can simulate dehydration in concrete with Portland fly ash cement. The aim of the study is to investigate how moisture simulations in PPB differ from executed moisture measurements in four concrete samples with two different w/c ratio. By storing the samples in different environments, the goal is to experimentally measure how the environment affects the dehydration. The goal is also to show differences between moisture simulations with the built-in climate data in PPB and with the own measured climate data. The results from the experimental studies show that the dehydration became larger in concrete samples with w/c ratio 0.40 than for samples with w/c ratio 0.55 after 70 days. Samples that had been stored in a stable indoor environment had dried more than samples that had been stored in a varying outdoor environment, which in this study did not correspond to simulations in PPB. The result of this study shows that simulations in PPB tend to show slightly greater dehydration than executed moisture measurements. This overestimation is greater in simulations with a varying outdoor environment than with a stable indoor environment. The overestimation is greater in simulations with the built-in climate data in PPB than with the own measured climate data. When adjusting the maximum temperature of the concrete in PPB to the actual measured maximum temperature, the moisture simulations is positively affected so that they approach the experimentally obtained results. Concrete with low w/c ratio is more affected by such an adjustment than concrete with high w/c ratio. The conclusion in this study is based on simulations and moisture measurements in a few concrete samples, which may have been exposed to disturbances. More studies are needed to validate the reliability of the PPB software. Choice of curing method and maximum temperature during curing can affect the drying and simulations in PPB. The experiments indicate that simulations with the PPB software tend to deviate if concrete with a high w/c ratio is exposed to water shortly after casting. Correct maximum temperature in PPB is important for a more real simulation of dehydration in concrete, especially at high w/c ratio. Simulations in PPB tend to be more accurate when using own climate data than using the built-in climate data.

This study reviews the theoretical and experimental aspects of the X-ray diffraction (XRD) technique and evaluates its use in identifying toxic elements or compounds in waste that has been incinerated. Many industries incinerate materials that contain large significant amounts of toxic elements, and these elements should be identified and re-moved to reduce environmental pollution. The aim of this project is to identify the elemental content of an incinerated ash sample, and to recommend a proper identification method when using XRD. Here, we test two ash samples (raw ash without any treatment and ash that has been stabilized by washing) using the software DIFFRAC.EVA that is integrated into Bruker’s diffractometer D2Phaser to match different diffraction patterns to identify the contents of the ash sample. Finally concluding the results XRF is more suitable than XRD for ash surveil-lance.

As cinzas de carvão são subprodutos da combustão de carvão mineral gerados em grandes quantidades a partir de usinas termelétricas no mundo todo. Nos últimos anos, pesquisas sobre a utilização das cinzas estão sendo desenvolvidas visando soluções sustentáveis, garantindo, assim, a preservação do meio ambiente e a saúde humana. As cinzas de carvão podem ser aproveitadas como matéria-prima para síntese de zeólita, material este que possui uma vasta gama de aplicações industriais. Em muitas dessas aplicações é requerido o uso de formas peletizadas de zeólitas. Nesse contexto, o objetivo do presente estudo foi desenvolver um método de obtenção de zeólita de cinzas leves de carvão na forma granular e avaliar seu uso como material adsorvente. A primeira etapa deste estudo consistiu na síntese e caracterização de zeólita convencional (ZCL) e de zeólita do tipo NaA com alto grau de pureza (ZA). As cinzas leves de carvão utilizadas na síntese das zeólitas foram coletadas na Usina Termelétrica Jorge Lacerda, localizada no Estado de Santa Catarina, Brasil, o maior complexo termelétrico a carvão da América Latina. O material de partida e as zeólitas sintetizadas em pó foram caracterizados em termos da composição química, composição mineralógica, morfologia, capacidade de troca catiônica, estabilidade térmica, área superficial específica, distribuição de poros e dos grupos funcionais. As fases zeolíticas formadas por tratamento hidrotérmico foram hidroxisodalita e traços de NaX. A zeólita do tipo NaA foi sintetizada por método de duas etapas apresentando grau de pureza de 84%. O valor de capacidade de troca catiônica da zeólita A com alto grau de pureza foi aproximadamente duas vezes maior do que o valor encontrado para a zeólita convencional (1,84 meq g-1 para ZCL e 3,81 meq g-1 para ZA). Na segunda etapa, os produtos zeolíticos sintetizados neste estudo foram peletizados com a aplicação de diferentes métodos. Os grânulos de zeólitas foram formados manualmente na forma de esferas na faixa de tamanho entre 3 mm e 7 mm a partir da mistura das zeólitas em pó com um ou mais agentes aglutinantes e adição de água deionizada. As diferentes metodologias experimentais de peletização das zeólitas sintetizadas foram comparadas e avaliadas por meio da determinação da capacidade de troca catiônica dos produtos obtidos, trabalhabilidade, resistência mecânica e estabilidade em água. O método de peletização no qual as argilas caulinita e bentonita foram usadas como agentes aglutinantes, na proporção de 5% em massa cada, foi considerado o melhor para a zeólita convencional. Para a zeólita A, foi selecionado o método com 10% de bentonita. Os valores de capacidade de troca catiônica dos produtos zeolíticos foram mantidos após o processo de peletização. Posteriormente foi realizado um estudo direcionado à aplicação da zeólita granular no tratamento de água. A amostra de zeólita A com alto grau de pureza peletizada, obtida pelo método otimizado, foi selecionada para ser usada como material adsorvente no processo de adsorção de íons cádmio em solução aquosa em coluna de leito fixo. Os resultados evidenciaram a potencialidade do uso da zeólita A peletizada no tratamento de efluentes. / Coal ashes are by-products of coal combustion generated in large quantities from thermoelectric plants worldwide. In recent years, research on the use of ash has been developed aiming at sustainable solutions, thus guaranteeing the preservation of the environment and human health. Coal ashes can be used as raw material for zeolite synthesis, which has a wide range of industrial applications. In many such applications the use of zeolite pelletized forms is required. In this context, the objective of the present study was to develop a method to obtain zeolite of light ash from coal in the granular form and to evaluate its use as an adsorbent material. The first step of this study was the synthesis and characterization of zeolite conventional (ZFA) and of the zeolite NaA type with a high degree of purity (ZA). The coal fly ashes used in the synthesis of the zeolites were collected in the Thermoelectric Complex Jorge Lacerda, located in the Santa Catarina State, Brazil, the largest coal burning thermoelectric complex of Latin America. The starting material and the zeolites synthesized in powder were characterized in terms of chemical composition, mineralogical composition, morphology, cation exchange capacity, thermal stability, specific surface area, pore distribution and functional groups. The zeolitic phases formed by conventional hydrothermal treatment were hydroxysodalite and traces of NaX. The zeolite of the NaA type was synthesized by a two-step method with a fusion step having a degree of purity of 84%. The value of cation exchange capacity of zeolite A with high purity was approximately two times higher than the value found for the zeolite conventional (1.84 meq g-1 for ZFA and 3.81 meq g-1 for ZA). In the second step, the zeolitic products synthesized in this study were pelletized with the application of different methods. The zeolite granules were formed manually in the form of spheres in the size range between 3 mm and 7 mm from the powder mixture of zeolite with one or more binders and addition of deionized water. The different experimental methodologies of pelletization the synthesized zeolites were compared and evaluated through of the determination of the cation exchange capacity, workability, mechanical strength and water stability. The pelletization method in which clays kaolinite and bentonite were used as binders in the proportion of 5% by weight each was considered the best for the conventional zeolite. For zeolite-A, was selected the method with 10% bentonite. The cation exchange capacity values of the zeolitic products were maintained after the pelletization process. Subsequently, a study was carried out on the application of granular zeolite in water treatment. The zeolite-A sample with high degree of pelletized purity, obtained by the optimized method, was selected to be used as adsorbent material in the adsorption process of cadmium ions in aqueous solution in a fixed bed column. The results evidenced the potential of the use of pelletized zeolite-A in the treatment of effluents.

Os tripanosomas são parasitas hemoflagelados com importância médica para humanos e animais domésticos. Surtos de infecções agudas graves por T.vivax têm sido relatados em todo Brasil onde perdas econômicas e falhas reprodutivas são observadas. Neste trabalho, uma infecção experimental por T. vivax em ovinos confirmou sua transmissão transplacentária. Em relação à epidemiologia de T. vivax, para entender o papel dos jumentos em surtos no Semiárido Brasileiro, foram realizados ensaios parasitológicos e moleculares em infecções naturais e experimentais. Nossos resultados mostraram animais assintomáticos, portanto, podem atuar como potenciais reservatórios. Além disso, estudos filogenéticos revelaram uma diversidade genética inesperada em tripanossomas no Leste da África, especialmente em moscas tsé-tsé. Novos genótipos de T. vivax foram caracterizados e tripanossomas do subgênero Nanomonnas se mostraram prevalentes nestas infecções. Nesta abordagem, conseguimos identificar T. suis e novas espécies do subgênero Pycnomonas presentes em animais selvagens e domésticos. / Trypanosomes are hemoflagellates parasites with medical importance to humans and domestic animals. Outbreaks of severe acute infections by T. vivax have been reported throughout Brazil, where economic loss and reproductive failure are observed. In this study, an experimental infection by T. vivax in sheep confirmed the transplacental transmission of this parasite. Regarding T. vivax epidemiology, to understand the role played by donkeys in outbreaks in the Brazilian Semiarid, we performed parasitological and molecular assays in naturally and experimentally infections. Our findings show that infected donkeys are asymptomatic and, thus, are potential reservoirs. In addition, phylogenetic studies have revealed an unexpected genetic diversity in East Africa, especially in tsetse flies. New genotypes of T. vivax were characterized and trypanosomes of the subgenus Nanomonnas were prevalent in these infections. In this approach, we can identify T. suis and new species of the subgenus Pycnomonas present in wild and domestic animals.

Cinza leve de carvão, resíduo gerado em usina termelétrica, foi usada para sintetizar zeólita por meio de tratamento hidrotérmico com solução de NaOH. A cinza leve (CL-2) e a zeólita sintética (ZM-2) que foi predominantemente identificada como hidroxi-sodalita foram utilizadas como adsorventes dos corantes aniônicos índigo carmina (IC) e reativo laranja 16 (RL16) de soluções aquosas. Nos processos de adsorção, os efeitos de tempo de contato, concentração inicial de corantes, pH, massa de adsorventes e temperatura foram avaliados. O estudo cinético de adsorção demonstrou que os resultados apresentaram melhor ajuste ao modelo de pseudo-segunda ordem e que adsorção de superfície e difusão intrapartícula participaram no mecanismo de adsorção. Os parâmetros termodinâmicos demonstraram que a adsorção foi espontânea em todos os processos de adsorção. Os processos de adsorção foram de natureza endotérmica para todos os sistemas, com exceção do sistema IC/ZM-2, em que foi exotérmico. Os dados de entropia mostraram a ocorrência do aumento da desordem na interface sólido/solução durante a adsorção em todos os sistemas, exceto novamente no IC/ZM-2, no qual se verificou a diminuição da desordem na interface. As isotermas de adsorção ajustaram-se à equação linear de Langmuir. As capacidades máximas de adsorção foram 1,48 mg/g para o sistema IC/CL-2; 1,13 mg/g para IC/ZM-2; 0,96 mg/g para RL16/CL-2 e 1,14 mg/g para RL16/ZM-2 à temperatura ambiente. O estudo de dessorção realizado com água, com soluções aquosas ácidas e com solução aquosa básica demonstrou ser ineficiente tanto para a recuperação dos corantes quanto para a regeneração dos adsorventes. / Coal fly ash, a waste generated in coal-fired electric power plant, was used to synthesize zeolite by hydrothermal treatment with NaOH solution. The fly ash (CL-2) and this synthesized zeolite (ZM-2) that was characterized as hydroxy-sodalite were used as adsorbents for anionic dyes indigo carmine (IC), and reactive orange 16 (RO16) from aqueous solutions. Effects of contact time, initial dye concentration, pH, adsorbent mass, and temperature were evaluated in the adsorption processes. The kinetics studies indicated that the adsorption followed the pseudo-second order kinetics and that surface adsorption and intraparticle diffusion were involved in the adsorption mechanism. The thermodynamics parameters demonstrated that the adsorption was spontaneous for all adsorption processes. The enthalpy data confirmed the endothermic nature for all adsorption processes except for IC/ZM-2 system which was exothermic. The entropy data showed an increased disorder at the solid/solution interface during the adsorption for all systems except for IC/ZM-2 whose negative entropy value indicated a decreased disorder at the interface. The adsorption isotherms were closely fitted to the Langmuir linear equation. The maximum adsorption capacities were 1.48 mg/g for the IC/CL-2 system; 1.13 mg/g for IC/ZM-2; 0.96 mg/g for RO16/CL-2, and 1.14 mg/g for RO16/ZM-2 at room temperature. The desorption study carried out with water, with acid aqueous solutions, and with an alkali aqueous solution showed to be inefficient both for recovering the dyes and regenerating the adsorbents.