Στόχος της διπλωματικής εργασίας είναι η μελέτη των χαρακτηριστικών του ασύρματου καναλιού και πιο συγκεκριμένα κάποιων παραμέτρων του που παίζουν σημαντικό ρόλο στην καλύτερη κατανόηση του. Στο πρώτο κεφάλαιο γίνεται μία εισαγωγή σε έννοιες όπως η διάδοση του ηλεκτρομαγνητικού κύματος και το ασύρματο κανάλι σε γενικευμένη μορφή. Στο δεύτερο κεφάλαιο παρουσιάζονται όλες οι παράμετροι που επιδρούν και επηρεάζουν τη διάδοση του κύματος καθώς και οι διαφορετικοί τρόποι με τους οποίους το ηλεκτρομαγνητικό κύμα διαδίδεται στο χώρο. Το τρίτο κεφάλαιο διαπραγματεύεται την χρήση μοντέλων αλλά και την στατιστική περιγραφή του καναλιού λόγω του σύνθετου και πολύπλοκου χαρακτήρα της φύσης του καναλιού. Ακόμα εισάγεται η έννοια και η χρησιμότητα του συντελεστή Rice K. Στο τέταρτο κεφάλαιο έχουμε την παρουσίαση των μοντέλων που χρησιμοποιούνται στο ασύρματο κανάλι εσωτερικού χώρου για την τοπολογία του αεροδρομίου Αθηνών και την λήψη μετρήσεων σε αυτό ώστε να γίνει αξιολόγηση με βάση της μετρήσεις και να καταλήξουμε στο καταλληλότερο προς χρήση μοντέλο. Τέλος στο πέμπτο κεφάλαιο γίνεται μία θεωρητική προσέγγιση υπολογισμού του συντελεστή Κ, αλλά και ο υπολογισμός του με βάση μετρήσεις που πήραμε στο αεροδρόμιο και η εξαγωγή κάποιων συμπερασμάτων. / -

Η Τέφρα Φλοιού Ρυζιού (ΤΦΡ) είναι ένα από τα κυριότερα γεωργικά απόβλητα και προέρχεται από την καύση του φλοιού ρυζιού (ΦΡ) στις ορυζοβιομηχανίες για παραγωγή ενέργειας ή και μείωσης του όγκου των αποβλήτων. Η τέφρα φλοιού ρυζιού αποτελεί περίπου το 18-20% του φλοιού του ρυζιού, ο οποίος αποτελεί περίπου το 20% του ακατέργαστου ρυζιού ενώ συνήθως είναι κρυσταλλική. Καθώς ο παγκόσμιος όγκος της ετήσιας παραγωγής σε ρύζι και κατ’ επέκταση σε τέφρα φλοιού ρυζιού αυξάνεται διαρκώς, εγείροντας περιβαλλοντικά και οικονομικά ζητήματα, η ανεύρεση ενός αποδοτικού και οικολογικού τρόπου εκμετάλλευσης της είναι θέμα μείζονος σημασίας. Παράλληλα, τα υψηλά ποσοστά της ΤΦΡ σε διοξείδιο του πυριτίου την καθιστούν πιθανή πηγή πυριτίου για πολλές εφαρμογές, μία από τις οποίες είναι και οι σύνθεση ζεόλιθων. Στην παρούσα εργασία μελετήθηκε η αξιοποίηση κρυσταλλικής ΤΦΡ στην σύνθεση τεσσάρων τύπων ζεόλιθων και συγκεκριμένα των MFI, FAU, BEA και LTA. Για τον σκοπό αυτό αρχικά χαρακτηρίστηκε η πρώτη ύλη, δηλαδή η ΤΦΡ, τόσο ως προς την χημική της σύσταση και περιεκτικότητα σε άκαυτο άνθρακα όσο και ως προς την κρυσταλλική δομή της. Στη συνέχεια εξακριβώθηκαν οι συνθήκες καύσης του ΦΡ οι οποίες οδηγούν στην μετατροπή από την άμορφη στην κρυσταλλική δομή του διοξειδίου του πυριτίου, η οποία ονομάζεται χριστοβαλίτης. Εφόσον αυτή η κρυσταλλική δομή είναι ακατάλληλη για την παραγωγή ζεόλιθων, μελετήθηκε η δυνατότητα διαλυτοποίησης της ΤΦΡ σε υδατικό διάλυμα καυστικού νατρίου ώστε να καταστραφούν οι κρύσταλλοι και να παραληφθεί άμορφο διοξείδιο του πυριτίου. Για το σκοπό αυτό, επιλέχθηκαν οι μοριακές αναλογίες των πρώτων υλών που οδηγούν στη σύνθεση καθενός από τους τέσσερεις τύπους ζεόλιθων και η ΤΦΡ επεξεργάστηκε με την κατάλληλη αναλογία καυστικού νατρίου σε υδατικό διάλυμα σε διάφορες θερμοκρασίες και συνθήκες. Παρατηρήθηκε κρυστάλλωση του επιθυμητού τύπου ζεόλιθου σε κάθε μία από τις περιπτώσεις που εξετάστηκαν, ενώ το ποσοστό της διάλυσης του χριστοβαλίτη βρέθηκε ότι είχε την σημαντικότερη επίδραση στην απόδοση της διεργασίας και την καθαρότητα του προϊόντος. Ταυτόχρονα διαπιστώθηκε ότι το ποσοστό της διάλυσης του χριστοβαλίτη εξαρτάται κυρίως από την αναλογία μαζών RHA/NaOH και βρέθηκαν οι κατάλληλες τιμές. Καθώς το μεγαλύτερο ποσοστό διαλυμένου χριστοβαλίτη παρατηρήθηκε στην περίπτωση της σύνθεσης του ζεόλιθου LTA, η οποία επιπλέον δεν χρειάζεται οργανικό παράγοντα δομής ούτε υψηλές θερμοκρασίες, επιλέχθηκε να χρησιμοποιηθεί για την μελέτη και την βελτιστοποίηση της διεργασίας. Συγκεκριμένα, εξετάστηκαν διαφορετικές μέθοδοι επεξεργασίας της ΤΦΡ με καυστικό νάτριο, σε μεγάλο θερμοκρασιακό και χρονικό εύρος, ώστε να μελετηθεί η κινητική της διάλυσης του χριστοβαλίτη και να βρεθεί η ενέργεια ενεργοποίησης της. Στη συνέχεια μελετήθηκε η επίδραση της θερμοκρασίας και της διάρκειας στην κρυστάλλωση του ζεόλιθου LTA ώστε να μελετηθεί η κινητική της αντίδρασης και να βρεθεί η ενέργεια ενεργοποίησης της καθώς και οι βέλτιστες συνθήκες απόδοσης της διεργασίας και καθαρότητας του τελικού προϊόντος. Τέλος, εξετάστηκε η επίδραση δύο σημαντικών παραμέτρων, της θερμοκρασίας σύνθεσης και της ταχύτητας ανάδευσης στην ποιότητα του τελικού προϊόντος και βρέθηκαν οι βέλτιστες τιμές τους. Τα αποτελέσματα και τα συμπεράσματα από την παρούσα εργασία, έχουν κατατεθεί στον Οργανισμό Βιομηχανικής Ιδιοκτησίας (Ο.Β.Ι.), για την χορήγηση Διπλώματος Ευρεσιτεχνίας (Δ.Ε.), με αριθμό αίτησης: 20120100391. / Rice husk ash (RHA) is one of the major agricultural wastes and results from the combustion of rice husk (RH) at rice in milling facilities for energy production or waste volumes reduction. Rice husk ash is about 18-20% of the cortex of the rice, which is approximately 20% of raw rice and is usually in its crystalline form. As the global volume of annual production in rice and hence rice husk ash is increasing, raising environmental and economic issues, finding an efficient and ecological way of RHA exploitation is a major issue. In addition, the high rates of RHA on silica render possible silicon source for many applications, one of which is the synthesis of zeolites. In this study, the use of crystalline RHA in the synthesis of four zeolite types, namely MFI, FAU, BEA and LTA was investigated. For this purpose, the raw material, i.e. RHA, was characterized both in terms of its chemical composition and unburned carbon content as well as its crystalline structure. Afterwards, the combustion conditions of RH which lead to the conversion from the amorphous to the crystalline structure of silica, called cristobalite, were determined. Since this crystalline structure is unsuitable for the production of zeolites, the possibility of solubilizing RHA in aqueous sodium hydroxide solution was investigated, in order to destroy the crystals and receive amorphous silica. For this purpose, the molar ratios of the raw materials which would result in the synthesis of each of the four types of zeolites were selected and RHA was treated with the appropriate amount of sodium hydroxide in aqueous solution at various temperatures and conditions. The crystallization of the desired zeolite type in each of the cases examined was verified, while the rate of dissolution of cristobalite was found to have the most significant effect on the process efficiency and the product purity. Simultaneously, it was found that the rate of dissolution of cristobalite mainly depends on the mass ratio of RHA / NaOH and the most suitable values were determined. As the majority of dissolved cristobalite was observed in the case of LTA synthesis, which moreover does not require organic structure directing agent nor high temperatures, it was chosen to be used for the study of design and optimization process. Specifically, several methods of RHA treatment with sodium hydroxide at high temperature and time range were examined, in order to study the kinetics of dissolution of cristobalite and to find the activation energy. Then, the influence of temperature and duration on the crystallization of LTA was examined in order to study the kinetics of the reaction and to determine the activation energy as well as the optimum conditions of the process in terms of efficiency and final product purity. Finally, the effect of two important parameters, the temperature of the synthesis and the stirring speed, on the final product quality was investigated and the optimal values were found. The results and the conclusions of this study, have been submitted to the Hellenic Industrial Property Organization for the grant of Patent with application number: 20120100391.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Commercial formulations of the herbicide clomazone have been widely used in agriculture and fish farming to control weeds. Fish can be affected when the water reaches the drainage waterways, causing an imbalance in the aquatic ecosystem. In order to evaluate a possible contamination, we determined LC50 (96h) using a commercial formulation containing clomazone (Gamit®). We verified the metabolic, enzymatic, and genotoxic parameters as well as the oxidative stress in juvenile carp (Cyprinus carpio). Firstly, in order to determine the LC50 for the acute toxicity test, , the animals were exposed to the concentrations of 10, 20, 30, 40 and 50 mg/L of clomazone for 96 h and the fish behavior was analyzed during this period. After exposure, we verified the activity of the enzyme acetylcholinesterase (AChE) in muscle and brain of the dead fish and the live carp. Secondly, fish were exposed to the herbicide for 7 days, both in field (rice crop) and laboratory conditions. The concentration used in the rice crop and the laboratory was 0.5 mg/L. After the experimental period of 7 days under laboratory conditions and 7, 30, and 90 days under rice crop conditions, brain, liver and muscle of fish were sampled to carry out the toxicological analysis. The parameters studied were enzymatic activity of AChE, catalase (CAT) and glutathione S-tranferase (GST) in different tissues of this species. Some markers of oxidative stress, such as protein carbonylation and thiobarbituric acid reactive substances (TBARS) levels in liver tissue were also analyzed. Some metabolic parameters such as glucose, glycogen, lactate, protein, and ammonia as well as amino acids in liver and muscle of carp were also measured. In plasma, we measured glucose, lactate, and protein. Thirdly, carp were exposed to approximately 15% of the LC50 (5.0 mg/L) for 7 days. We verified the formation of reactive oxygen species (ROS) and micronucleus, and the comet test was performed in order to investigate the presence of DNA damage. In the first study we observed that fish exposed to 20, 30, 40 and 50 mg/L showed behavioral changes and LC50 (96h) was 30.35 mg/L. In addition, it was found that the activity of the enzyme AChE showed no significant changes in the brain of the fish that died at the concentrations tested (30, 40 and 50 mg/L), and the muscle of dead fish had an increase in this enzyme when they were exposed to 50 mg/L of clomazone. The activity decreased significantly in the brain AChE of fish that remained alive after 96 h of exposure to 10, 20 and 30 mg/L, but increased in the muscle of the surviving fish exposed to all concentrations tested. In the second experiment results showed that fish exposed to 7 days had no changes in AChE under field conditions. However, a decrease in the activity of this enzyme in muscle was observed under laboratory conditions. During the same period of exposition, the parameters of oxidative stress conditions changed both under the field and in laboratory conditions. However, metabolic parameters were altered only under field conditions. After 30 and 90 days, AChE activity did not change under field conditions. Disturbances in oxidative stress parameters and metabolism in different tissues were evident in the tissues up to 90 days after treatment. The results showed that the activity of AChE changed only under laboratory conditions, and that oxidative stress associated with metabolic parameters can be good indicators of contamination for clomazone in C. Carpio in rice field conditions. In the third experiment, the results showed an increased formation of ROS and a significant micronucleus (MN) and DNA damage in erythrocytes after exposure to 5.0 mg/L of the herbicide clomazone. Given these results, we can conclude that the herbicide studied can be dangerous to Cyprinus carpio when exposed to it due to increased ROS, which in turn cause oxidative stress evidenced by changes in enzyme markers, metabolic, genotoxic and oxidative stress. However, further studies are needed in order to verify the safety of this herbicide is when associating rice and fish. / As formulações comerciais do herbicida clomazone têm sido amplamente utilizadas na agricultura e na piscicultura para controle de plantas daninhas. Os peixes podem ser afetados quando as águas de drenagem atingem os cursos d água, acarretando um desequilíbrio no ecossistema aquático. Para avaliar uma possível contaminação foi determinada a CL50 (96h) utilizando-se uma formulação comercial contendo clomazone (Gamit®) verficando-se parâmetros metabólicos, enzimáticos, genotóxicos e de estresse oxidativo em juvenis de carpas (Cyprinus carpio). Para o teste de toxicidade aguda, a fim de determinar a CL50, os peixes foram expostos às concentrações 10, 20, 30, 40 e 50 mg/L de clomazone em água durante 96 horas e o comportamento dos peixes foi analisado nesse período. Após a exposição, foi verificada a atividade da enzima acetilcolinesterase (AChE) no cérebro e músculo dos peixes mortos e das carpas que sobreviveram. No segundo experimento, os peixes foram expostos ao herbicida durante sete dias, tanto em condição de campo (lavoura de arroz irrigado) como de laboratório. A concentração utilizada na lavoura de arroz e no laboratório foi de 0,5 mg/L. Decorridos os períodos experimentais de 7 dias em condições de laboratório, e 7, 30 e 90 dias em condições de lavoura de arroz, foram retirados o cérebro, o fígado e o músculo dos peixes para realização das análises toxicológicas. Os parâmetros enzimáticos analisados foram a atividade da AChE, catalase (CAT) e glutationa S-transferase (GST). Também foram analisados alguns marcadores de estresse oxidativo, como a carbonilação de proteínas e níveis das substâncias reativas ao ácido tiobarbitúrico (TBARS) no tecido hepático. Por fim, foram avaliados alguns parâmetros metabólicos como: glicose, glicogênio, lactato, proteína, amônia e os aminoácidos em fígado e em músculo de carpas. No plasma, foram feitas as dosagens de glicose, de lactato e de proteína. Em um terceiro experimento, as carpas foram expostas a aproximadamente 15% do valor obtido para a CL50 (5,0mg/L) por 7 dias. Posteriormente, foi verificada a formação das espécies reativas de oxigênio (EROs) e foram realizados os testes do micronúcleo e cometa (expresso por índice de dano do DNA). No primeiro experimento, foi observado que os peixes expostos a 20, 30, 40 e 50 mg/L, mostraram mudanças comportamentais e a CL50 (96h) foi 30,35 mg/L. Além disso, foi verificado que a atividade da enzima AChE não apresentou alterações significativas no cérebro dos peixes que morreram nas concentrações testadas (30, 40 e 50mg/L), e no músculo dos peixes mortos houve uma elevação na atividade desta enzima, quando eles foram expostos a 50 mg/L de clomazone. Já a atividade AChE diminuiu significativamente no cérebro dos peixes que sobreviveram após 96h de exposição a 10, 20 e 30mg/L, no entanto, aumentou no músculo dos peixes sobreviventes expostos a todas as concentrações testadas. No segundo experimento, os resultados mostraram que os peixes expostos a 7 dias não apresentaram alterações na AChE em condições de campo. No entanto, uma diminuição da atividade desta enzima no músculo foi observada em condições de laboratório. Durante o mesmo período de exposição, os parâmetros de estresse oxidativo mudaram tanto em condições de campo quanto em laboratório. Entretanto, os parâmetros metabólicos foram alterados apenas em condições de campo. Após 30 e 90 dias, a atividade da AChE não se alterou em condições de campo. Distúrbios nos parâmetros de estresse oxidativo e metabolismo foram evidentes nos tecidos até 90 dias após a aplicação. Os resultados mostraram que a atividade da AChE alterou apenas em condições de laboratório, e que marcadores de estresse oxidativo associados aos parâmetros metabólicos podem ser bons indicadores de contaminação para o clomazone em C. carpio em condições de campo. No terceiro experimento, os resultados mostraram um aumento da formação das EROs e significativo aumento dos MN e de danos no DNA dos eritrócitos após a exposição a 5,0 mg/L do herbicida clomazone. De acordo com os resultados obtidos, conclui-se que o herbicida estudado pode ser perigoso para as carpas quando expostas, devido ao aumento das EROs que por sua vez causam estresse oxidativo, evidenciado por alterações em marcadores enzimáticos, metabólicos, genotóxicos e de estresse oxidativo. Contudo, mais estudos serão necessários para verificar a segurança desse herbicida para os cultivos associados utilizando-se arroz e peixes.

Na primeira etapa deste trabalho foi avaliada a potencialidade do uso da cinza de casca de arroz como carga em polipropileno (PP) comparando-a com o talco que é a carga mineral mais utilizada em polímeros. Esta comparação foi feita utilizando os compósitos formados por polipropileno com 20% da cinza de casca de arroz assim como, os formados por polipropileno com 20% de talco, determinando as suas propriedades. Apesar das propriedades do compósito de PP com a carga de 20% de cinza de casca de arroz apresentarem resultados inferiores em relação àqueles quando se utilizou o talco como carga, pode-se dizer que a cinza de casca de arroz pode ser usada como carga para outros usos menos nobres do PP. Desta forma se está dando um destino para esse resíduo que hoje é descartado no meio ambiente contribuindo assim, para a preservação do mesmo, além de reduzir o custo do produto. Este trabalho também teve como objetivo estudar o efeito da radiação ionizante nas propriedades destes compósitos de PP com 20% de cinza de casca de arroz. Utilizou-se o agente de acoplagem, anidrido maleico, para verificar se houve melhora na homogeneização das amostras. Em virtude do PP ser um polímero semicristalino, quando exposto ao processo de irradiação, tem sua morfologia modificada devido aos mecanismos de cisão das cadeias poliméricas. Este fato é atribuído aos mecanismos de cisão das cadeias poliméricas, que está de acordo com a literatura. / In the first step of this work, it was evaluated the possibility of using rice husk ash as a filler in polypropylene (PP) making a comparison with talc which is the most used mineral filler in polymers. This comparison was made by using polypropylene with 20% rice husk ash as well as polypropylene with 20% talc measuring their properties. Despite the properties of the PP with 20% rice husk ash decreased compared with the composite of polypropylene with 20% talc it can be said that the rice husk ash can be used as filler for or other utilization less noble of PP . This way it is being given a destination for this residue that it is disposable in the environment contributing to its preservation, moreover reducing the product cost. This work had also as an aim to study the ionizing radiation effect in the properties of these composites. It was used the coupling agent, maleic anhydride , to verify a best sample homogenization. According to the results it can be said that PP is a semicrystalline polymer, and so it has its morphology modified when exposed to the irradiation process. This fact is due to the scission mechanisms of the polymeric chains which it is in compliance to the literature.

Made available in DSpace on 2014-06-11T19:30:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-02-17Bitstream added on 2014-06-13T19:19:21Z : No. of bitstreams: 1 boock_mv_dr_jabo.pdf: 816842 bytes, checksum: 01fc8022e8314991c83533aef2b391ec (MD5) / Universidade Estadual Paulista (UNESP) / Os sistemas de aquicultura integrada otimizam o uso dos recursos naturais, das instalações e da mão-de-obra, ampliando a sustentabilidade ambiental e econômica. Permitem ainda, a transformação de poluentes em biomassa de alto valor econômico. No presente estudo foram estudadas duas espécies de camarões de água doce, o camarão-da-malásia (M. rosenbergii) e o camarão-daamazônia (M. amazonicum), criados em sistema integrado simultâneo com a cultura do arroz irrigado por inundação na região nordeste do Estado de São Paulo. As variáveis de produção: comprimento, peso, produção e produtividade foram estudadas para ambas as espécies de camarão. Para o sistema de monocultivo do arroz avaliou-se a produção e a produtividade do arroz, comparando-se estas às obtidas para o sistema de rizicarcinicultura. Indicadores de viabilidade econômica foram calculados para os sistemas de monocultivo de arroz e de rizicarcinicultura. Os indicadores de sustentabilidade ambiental foram calculados para comparar a sustentabilidade dos sistemas de monocultivo de arroz e da rizicarcinicultura (com M. amazonicum). Medições da emissão de gás metano (CH3 -), gás carbônico (CO2 -), estimativas da excreção de amônia (NH3 +) e do conteúdo de nitrogênio e fósforo nas fezes dos camarões também foram realizadas / Aquaculture integrated systems optimize the use of natural resources, facilities and manpower, expanding economical and environmental sustainability. They also allow to transform pollutants into biomass of high economic value. The present study focus on two species of freshwater prawns, Macrobrachium rosenbergii and Macrobrachium amazonicum, reared in a simultaneous integrated system with rice (Oryza sativa) culture irrigated by flooding, in the northeastern region of Sao Paulo State. Production variables were determined for both prawn species: length, weight, production and productivity. Production and productivity were also determined for the rice monoculture in order to compare with the production variables of the rice-prawn system. Financial feasibility indicators were determined for the rice monoculture and for the rice-prawn system. Environmental Sustainability indicators were calculated to compare the sustainability of rice monoculture system and rice-prawn (M. amazonicum) system. The emissions of methane gas (CH3 -) and carbonic gas (CO2 -) were measured; ammonium (NH3 +) excretion, nitrogen and phosphorus contents in feces of the prawns were estimated too

Made available in DSpace on 2014-06-11T19:28:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-04Bitstream added on 2014-06-13T19:16:46Z : No. of bitstreams: 1 takada_hm_me_botfca.pdf: 587174 bytes, checksum: 68fcfeed820ef9c331817e76b2f9fab3 (MD5) / Com o objetivo de avaliar a patogenicidade e a virulência de fungos entomopatogênicos ao gorgulho aquático do arroz irrigado, Oryzophagus oryzae, foram testados 24 isolados de Metarhizium anisopliae e 2 de Beauveria bassiana. Os bioensaios foram realizados em condições controladas (26+1°C e 12 horas de fotofase). Nos testes para determinar a concentração adequada, a espécie M. anisopliae, isolado E9, apresentou maior patogenicidade quando comparado aos isolados de B. bassiana. A mortalidade confirmada, provocada pelo M. anisopliae, teve início no 4º dia, aumentando em seguida até estabilizar-se no 8º dia. Para a seleção dos isolados de M. anisopliae, adultos dos insetos foram inoculados com 1 mL de suspensão fúngica a 5x108 conídios/mL (1,6x104 conídios/mm2). Todos os isolados foram patogênicos ao inseto, sendo que a mortalidade variou entre 9,3 e 85,3 %. Os isolados de M. anisopliae mais patogênicos foram CB-103, CB-104, CB-233, E9 e CB-10. No teste de produção, os isolados CB-104, CB-233 e CB-103 foram superiores ao padrão E9, apresentando-se promissores para a utilização no controle de Oryzophagus oryzae. / Strains of Metarhizium anisopliae and Beauveria bassiana were evaluated concerning their pathogenicity and virulence for control of the rice water weevil, Oryzophagus oryzae. Bioassay conditions were 26+1ºC and 12 h. light. M. anisopliae (E9 strain) was been more pathogenic than two Beauveria bassiana strains (CB-66 and CB-74). For Metarhizium anisopliae (E9 strain), the mean mortality started at 4th day, increasing soon after until stabilize at 8 th day. A screening of M. anisopliae isolates was done inoculating adults of the insect with 1 mL of spore suspension containing 5x108 conídia/mL (1.6x104 conídia/mm2). All isolates were pathogenic to the insect, causing mortality between 9.3 and 85.3%. The most pathogenic isolates were CB-103, CB-104, CB-233, E9 and CB-10. These 6 isolates were evaluated concerning their spore production on cooked rice. The isolates CB-104, CB-233 and CB-103 afforded the highests spores production, significantly higher compared to E9, showing potential to be used for Oryzophagus oryzae control.

Apesar do avanço tecnológico crescente na construção civil, a falta de durabilidade das estruturas de concreto, tanto em edificações como pavimentação, tem sido constatada com acentuada assiduidade e proporção. O compósito cimentício de elevada deformação, também conhecido como Engineered Cementitious Composites (ECC), foi difundido a partir do conceito de concretos de alto desempenho reforçado com fibras, visando suprir o comportamento frágil do concreto convencional e problemas relacionados à falta de durabilidade gerada, principalmente, devido à propagação de fissuras. Neste contexto, o Laboratório de Ensaio de Modelos Estruturais (LEME) da Universidade Federal do Rio Grande do Sul (UFRGS) consolidou, nos últimos cinco anos, um grupo de pesquisa voltado ao estudo do ECC aliado a utilização de materiais nacionais. A concepção tem sido baseada na aplicação de materiais que proporcionem custos mais baixos e fomentem questões de sustentabilidade ambiental. Assim, foram incorporados ao material, fibra de polipropileno (2% em volume) e substituição parcial do cimento por 30% (em volume) de cinza de casca de arroz residual. O presente trabalho visa analisar questões de durabilidade destes compósitos (com e sem a incorporação de cinza), e compará-los a concretos convencionais, através de ensaios relacionados ao estudo da estrutura de poros (absortividade, absorção e índice de vazios, absorção e água por capilaridade, absorção de água pelo método do cachimbo e microscopia eletrônica de varredura), penetração e difusão de íons cloretos, retração livre e restringida, e, por fim, resistência à abrasão. Os resultados obtidos indicam que a incorporação de cinza de casca de arroz melhorou significativamente as propriedades do compósito relacionadas à conexão e solução dos poros, dificultando a passagem de cloretos, além de apresentar resistência à abrasão semelhante ao compósito de referência. Sua desvantagem está relacionada às maiores aberturas de fissuras ocasionadas devido à retração restringida. Entretanto, o trabalho evidencia a viabilidade e vantagem do uso de cinza de casca de arroz na produção do compósito, em termos de durabilidade. / Despite the increasing technological advances in construction, the lack of concrete structures durability, both in buildings and pavement, have been found with severe attendance and proportion. The high strain cementitious composite, also known as Engineered Cementitious Composites (ECC), was widespread from the concept of high performance fiber reinforced concrete, in order to supply the fragile behavior of conventional concrete and problems related to lack of durability generated mainly due to crack propagation. In this context, the Laboratório de Ensaios e Modelos Estruturais (LEME) of the Federal University of Rio Grande do Sul (UFRGS) consolidated over the last five years, a research group focused on the ECC study allied with the use of national materials. The design has been based on the application materials that provide lower costs and promote environmental sustainability issues. Thus, they were incorporated into the material polypropylene fibers (2% by volume) and partial cement replacement of 30% (by volume) of residual rice husk ash. This study aims to examine durability issues of these composites (with and without rice husk ash), and compare them to conventional concretes, through tests related to the study of pore structure (absorptivity, absorption and void ratio, water absorption by capillarity, water absorption by the pipe method and scanning electron microscopy), penetration and diffusion of chloride ions, free and restrained shrinkage, and, finally, abrasion resistance. The results indicate that the incorporation of rice husk ash significantly improved material properties related to connection and pores solution, hindering the chloride ingress, and presents abrasion resistance similar to the reference composite. Its disadvantage is related to the larger cracks due to restrained shrinkage. However, the work demonstrates the viability and advantage of use rice husk ash in the composite production in terms of durability.

The research draws on an ethnographic research and explores the everyday practice of collective action in Ugbawka in Enugu State by using interviews and participant observation. The study reveals that smallholder collective action is not best fitted into formal institutional arrangement but takes place within a complex and intricate process that involves interaction with diversity of institutions and actors. Equally, the interactions that occur amongst actors are mediated at the community level through interplay of socio-cultural and political factors. This study recognises and places emphasis on understanding of agency and the exercise of agency at the local level arguing that smallholder farmers are not robot but active individual who exercise their agency purposively or impulsively depending on conditions and the assets available at their disposition as well as their ability to navigate the intricate power dynamic inherent at local context. The thesis thus questioned the simplistic use of formal institutional collective action framework in smallholder collective action at the community level and argues that institutions are not static and do not determine outcomes but are informed by the prevailing conditions at the community level. The study emphasises the role of existing institutions and socially embedded principles in community governance and argues that actors should be the focus of analysis rather than the system in understanding smallholder collective action. The study concludes by advocating for further research that could explore the possibility of hybrid approach that accepts the advantages of both formal and informal institutional forms of smallholder collective action.

A pesquisa relatada nesta dissertação teve por objetivo analisar a viabilidade técnica de estabilizar-se um solo sedimentar arenoso do Uruguai com cinza de casca de arroz (CCA) e cal. O solo utilizado apresenta baixo poder suporte, sendo pouco adequado para camadas de sub-base e base de pavimento rodoviário. Também não é adequado para ser estabilizado com cal e sua estabilização com cimento é muito custosa. Dois tipos básicos de CCA foram utilizados: uma cinza residual do processo de queima de casca de arroz em um forno sem controle de temperatura, e cinzas produzidas em laboratório por incineração de casca de arroz a diferentes temperaturas controladas. Foram realizados ensaios de difratogramas de raios-X, compactação, capacidade de suporte (ISC), compressão simples, tração por compressão diametral e durabilidade do solo, das CCA e das misturas solo-CCA-cal. Determinaram-se as influências do tempo de cura, dos teores de CCA e cal e dos tipos de CCA nos parâmetros de compactação, no ISC, no comportamento tensão-deformação e nas resistências à compressão simples e à tração por compressão diametral. Analisaram-se os efeitos da demora entre mistura e compactação no comportamento tensão-deformação e na resistência à compressão simples nas misturas com CCA residual e cal, além da sua durabilidade a ciclos de molhagem e secagem. As CCA produzidas a temperatura controlada entre 650°C e 800°C mostraram uma maior atividade pozolânica devido a sua estrutura amorfa. Os valores máximos de módulo de deformabilidade e resistência à compressão simples foram obtidos para as misturas com CCA a temperatura controlada. As misturas solo- CCA residual-cal desenvolveram resistência à tração demonstrando a ocorrência de reações pozolânicas. A estabilização do solo sedimentar arenoso com CCA e cal mostrou-se eficaz, permitindo o uso destes materiais em camadas de sub-base de pavimentos. / This MSc thesis was carried out with the purpose of analysing the technical feasibility of stabilizing a Uruguayan sandy soil with rice husk ash (RHA) and lime. The soil utilized present low bearing capacity and is not suitable for road pavement bases and sub-bases. It does not react to lime by itself and its stabilization with Portland cement is prohibitively expensive. Two kinds of RHA were used: a residual ash produced in the process of incinerating rice husk in an oven without temperature control, and ashes produced in laboratory by incineration of rice husk at different controlled temperatures. X-ray diffraction, compaction and bearing capacity (CBR), unconfined compression, split tensile and durability tests were carried out in the soil and in RHA samples and also in soil-RHA- lime mixtures. The influence of curing time, RHA and lime contents and RHA types in compaction parameters, CBR, strain-stress behaviour and unconfined compressive and split tensile strength were evaluated. The effects of the compaction delay on the stress-strain behaviour and the unconfined compression strength of the mixtures with residual RHA and lime were analysed. In order to investigate the mixtures durability, compacted specimens were submitted to wetting and drying cycles. Due to this amorphous structure, the RHA produced at controlled temperatures (650°C to 800°C) showed to be a more reactive concerning pozzolanic activity. The highest strain modulus and unconfined compression strength values were obtained for the mixtures with controlled temperature RHA. The soil-residual RHA-lime mixtures also developed tensile strength proving that pozzolanic took place. The stabilization of the sandy sedimentary soil with RHA and lime proved to be efficient, allowing the use of these materials in pavement sub-base layers.

Dois temas são característicos do contexto atual das organizações. Um, já consolidado, é o aumento da velocidade das inovações; o outro, é a necessidade de incorporar a perspectiva emergente da sustentabilidade nas práticas de inovação. A Teoria Neoschumpeteriana busca obter um domínio desses fenômenos dinâmicos da realidade econômica, em que a inovação, principalmente a tecnológica, é identificada como a força maior que propulsiona a dinâmica econômica. Entretanto, Hanusch e Pyka (2007) criticam a Teoria Neoschumpeteriana por entenderem que o desenvolvimento dos sistemas econômicos modernos incorpora a inovação tecnológica, assim como também a inovação organizacional, institucional e social e, por isso, os novos frameworks para estudos de sistemas econômicos, precisariam incorporar características de complexidade através do trânsito em diferentes teorias relevantes, levando em conta as raízes da Teoria Neoschumpeteriana, o que eles próprios não fazem. Assim, o objetivo geral de pesquisa foi o de propor um framework interteórico e complexo sobre a dinâmica da inovação e fazer a sua aplicação no Instituto Rio-Grandense do Arroz - IRGA. A metodologia utilizada foi de estudo de caso. Os dados foram coletados através de entrevistas e documentos. Cada uma das etapas realizadas na metodologia foi apoiada num estudo, a priori, sobre métodos que capturavam características de complexidade. A utilização de uma lógica abdutiva, prevista na metodologia, com constantes idas e vindas entre os conceitos teóricos construídos a priori e as informações advindas do campo empírico, fez emergir o conceito teórico de sistema econômico, como uma configuração complexa de múltiplos níveis de regras que se relacionam ao longo do tempo e se sucedem. Neste sentido, a presente pesquisa avançou ao identificar a emergência de regras, oriunda das teorias usadas, como uma qualidade nova e central, que em múltiplos níveis, compõe as configurações, que evoluem ao longo do tempo. Este avanço possibilitou estudar a história econômica do IRGA, não da perspectiva operacional, mas da perspectiva das regras genéricas, de maior nível, e das regras de menor nível associadas à regra genérica, numa perspectiva de configurações dinâmicas que evoluem, focado em inovações. A lógica abdutiva possibilitou avanços metodológicos na aplicação do método de análise qualitativa comparativa (QCA) no estudo das dinâmicas de configurações, já que o método tinha até então, sido aplicado numa abordagem estática. Os resultados indicaram, ainda, a presença de cinco regras genéricas no contexto de pesquisa do IRGA. O IRGA inseriu predominantemente, em suas atividades, de pesquisa a regra genérica de mais produtividade agrícola. As regras genéricas de gestão ambiental da propriedade agrícola, aumento do consumo do arroz, aumento da renda para o produtor foram inseridas nas atividades de pesquisa de modo marginal. A regra genérica denominada de negócios ambientais nas beneficiadoras de arroz ainda não foi inserida nas atividades de pesquisa do IRGA. A dinâmica de inserção destas regras genéricas no IRGA ocorre através de oito configurações de regras de nível zero e de segunda ordem, que seguem um conjunto de fases que foram denominadas de pré-distúrbio, origem, adoção, retenção e declínio. Uma característica nesta dinâmica é de que somente ocorreu a mudança de fase da regra genérica quando determinadas regras de segundo e de ordem zero estavam presentes. Como as fases de evolução das regras genéricas ocorreram em diferentes anos, no período entre 1969 e 2009, a combinação destas fases gerou seis configurações temporais de regras para inovação no IRGA. / Two themes are characteristic of the organizations on the current context. One is already established that is the increasing innovations speed. The other one is the need to incorporate the sustainability‘s emerging perspective in innovation practices. The Neo-Schumpeterian Theory seeks to obtain a domain on these dynamic phenomena of the economic reality, in which the innovation, especially technological, is identified as its greater propellent force. However, Hanusch and Pyka (2007) criticize the Neo-Schumpeterian Theory for understanding that the development of modern economic systems incorporate the technological innovation, as well as the organizational innovation, institutional, and social. Therefore, the new frameworks for the economic systems studies would need to incorporate some complexity features through traffic in different and relevant theories, taking into account the Neo-schumpeterian Theory roots, which they themselves do not do. Thus, the overall objective of this research was to propose an inter-theoretical and complex framework on the innovation dynamics and to make its application at the IRGA (Instituto Rio-Grandense de Arroz - Rice Institute of Rio Grande do Sul State, Brazil). We used the case study methodology. Data were collected by some interviews and from some documents. Each of the used methodology steps was supported in a priori study on methods that captured the complexity characteristics. The economic system‘s theoretical concept as a complex configuration of the multiple rules levels related over the time, and that succeed itself, came from an abductive logic use from the methodology, with constant goings and comings among the theoretical concepts a priori constructed, and from the empirical information from the field. In this sense, this research has advanced when identified the rules emergence, derived from the used theories as a new quality and centered, which at multiple levels composes the configurations that evolve over the time. This advance allowed the IRGA‘s economic history study, not from the operational perspective, but from the general rules perspectives of highest level and from the lowest level associated with the general rules perspectives, at a dynamic configurations perspective that evolve focusing on innovations. The abductive logic allowed the methodological advances in the method application of comparative and qualitative analysis (CQA) in the study of the configurations dynamics, since the method had until then been applied on a static approach. The results also indicated the presence of five generic rules in the context of the IRGA research. The IRGA inserted predominantly the general rule of most agricultural productivity in its research activities. The general rules of the farm environmental management, the increased rice consumption, and the increased income for producers have been included in the research activities marginally. The general rule of environmental affairs in the rice processing has not been incorporated into the IRGA research activities. The insertion dynamic of these general rules occurs through eight rules of level zero and second order configurations, which follow a stages set that were identified as pre-disturbance, origin, adoption, retention, and decay. A dynamic characteristic is that there was only a phase change of the general rule when certain rules of the second and zero order were present. As the phases of the generic rules development occurred in different years, from 1969 to 2009, these phases combination generated six rules temporal configurations for innovation in the IRGA.