A new testing method was introduced and developed to determine Mode I fracture toughness of disc type rock specimens. The new method was named as Straight Notched Disc Bending and it uses disc specimens under three-point bending. 3D Numerical modeling was carried out with a finite element program ABAQUS to find stress intensity factors for both well-known Semi-circular Bending specimen models and Straight Notched Disc Bending specimen models for varying disc geometries. Both specimen types included notches where a crack front is introduced at the tip of the notch to compute the stress intensity factors. For stress intensity analysis, crack front-upper loading point distance and span length between the two roller supports at the bottom boundary of the specimens were changed. Fracture toughness testing was carried on Ankara G&ouml / lbaSi pink colored andesite for both specimen types / crack front-upper loading point distance and span length between the two roller supports at the bottom boundary of the specimens were changed during the tests. For both specimen geometries, notch lengths changing from 5 mm to 20 mm were used. For each notch length, two different roller supports with span lengths 60 mm and 70 mm were used. For both methods, fracture toughness values determined by using numerically computed stress intensity factors and failure loads obtained from the experiments were very close / the new method was verified by comparing the results. The new method had advantages of lower confining pressure at the crack front and lower stress intensities with a possible smaller crack tip plasticity region.

Safety and reliability are prime concerns in aircraft performance due to the involved costs and risk to lives. Despite the best efforts in design methodology, quality evaluation in production and structural integrity assessment in-service, attainment of one hundred percent safety through development and use of a suitable in-flight health monitoring system is still a farfetched goal. And, evolution of such a system requires, first, identification of an appropriate Technique and next its adoption to meet the challenges posed by newer materials (advanced composites), complex structures and the flight environment. In fact, a quick survey of the available Non-Destructive Evaluation (NDE) techniques suggests Acoustic Emission (AE) as the only available method. High merit in itself could be a weakness - Noise is the worst enemy of AE. So, while difficulties are posed due to the insufficient understanding of the basic behavior of composites, growth and interaction of defects and damage under a specified load condition, high in-flight noise further complicates the issue making the developmental task apparently formidable and challenging. Development of an in-flight monitoring system based on AE to function as an early warning system needs addressing three aspects, viz., the first, discrimination of AE signals from noise data, the second, extraction of required information from AE signals for identification of sources (source characterization) and quantification of its growth, and the third, automation of the entire process. And, a quick assessment of the aspects involved suggests that Artificial Neural Networks (ANN) are ideally suited for solving such a complex problem. A review of the available open literature while indicates a number of investigations carried out using noise elimination and source characterization methods such as frequency filtering and statistical pattern recognition but shows only sporadic attempts using ANN. This may probably be due to the complex nature of the problem involving investigation of a large number of influencing parameters, amount of effort and time to be invested, and facilities required and multi-disciplinary nature of the problem. Hence as stated in the foregoing, the need for such a study cannot be over emphasized. Thus, this thesis is an attempt addressing the issue of analysis and automation of complex sets of AE data such as AE signals mixed with in-flight noise thus forming the first step towards in-flight monitoring using AE. An ANN can in fact replace the traditional algorithmic approaches used in the past. ANN in general are model free estimators and derive their computational efficiency due to large connectivity, massive parallelism, non-linear analog response and learning capabilities. They are better suited than the conventional methods (statistical pattern recognition methods) due to their characteristics such as classification, pattern matching, learning, generalization, fault tolerance and distributed memory and their ability to process unstructured data sets which may be carrying incomplete information at times and hence chosen as the tool. Further, in the current context, the set of investigations undertaken were in the absence of sufficient a priori information and hence clustering of signals generated by AE sources through self-organizing maps is more appropriate. Thus, in the investigations carried out under the scope of this thesis, at first a hybrid network named "NAEDA" (Neural network for Acoustic Emission Data Analysis) using Kohonen self-organizing feature map (KSOM) and multi-layer perceptron (MLP) that learns on back propagation learning rule was specifically developed with innovative data processing techniques built into the network. However, for accurate pattern recognition, multi-layer back propagation NN needed to be trained with source and noise clusters as input data. Thus, in addition to optimizing the network architecture and training parameters, preprocessing of input data to the network and multi-class clustering and classification proved to be the corner stones in obtaining excellent identification accuracy. Next, in-flight noise environment of an aircraft was generated off line through carefully designed simulation experiments carried out in the laboratory (Ex: EMI, friction, fretting and other mechanical and hydraulic phenomena) based on the in-flight noise survey carried out by earlier investigators. From these experiments data was acquired and classified into their respective classes through MLP. Further, these noises were mixed together and clustered through KSOM and then classified into their respective clusters through MLP resulting in an accuracy of 95%- 100% Subsequently, to evaluate the utility of NAEDA for source classification and characterization, carbon fiber reinforced plastic (CFRP) specimens were subjected to spectrum loading simulating typical in-flight load and AE signals were acquired continuously up to a maximum of three designed lives and in some cases up to failure. Further, AE signals with similar characteristics were grouped into individual clusters through self-organizing map and labeled as belonging to appropriate failure modes, there by generating the class configuration. Then MLP was trained with this class information, which resulted in automatic identification and classification of failure modes with an accuracy of 95% - 100%. In addition, extraneous noise generated during the experiments was acquired and classified so as to evaluate the presence or absence of such data in the AE data acquired from the CFRP specimens. In the next stage, noise and signals were mixed together at random and were reclassified into their respective classes through supervised training of multi-layer back propagation NN. Initially only noise was discriminated from the AE signals from CFRP failure modes and subsequently both noise discrimination and failure mode identification and classification was carried out resulting in an accuracy of 95% - 100% in most of the cases. Further, extraneous signals mentioned above were classified which indicated the presence of such signals in the AE signals obtained from the CFRP specimen. Thus, having established the basis for noise identification and AE source classification and characterization, two specific examples were considered to evaluate the utility and efficiency of NAEDA. In the first, with the postulation that different basic failure modes in composites have unique AE signatures, the difference in damage generation and progression can be clearly characterized under different loading conditions. To examine this, static compression tests were conducted on a different set of CFRP specimens till failure with continuous AE monitoring and the resulting AE signals were classified through already trained NAEDA. The results obtained shows that the total number of signals obtained were very less when compared to fatigue tests and the specimens failed with hardly any damage growth. Further, NAEDA was able to discriminate the"noise and failure modes in CFRP specimen with the same degree of accuracy with which it has classified such signals obtained from fatigue tests. In the second example, with the same postulate of unique AE signatures for different failure modes, the differences in the complexion of the damage growth and progression should become clearly evident when one considers specimens with different lay up sequences. To examine this, the data was reclassified on the basis of differences in lay up sequences from specimens subjected to fatigue. The results obtained clearly confirmed the postulation. As can be seen from the summary of the work presented in the foregoing paragraphs, the investigations undertaken within the scope of this thesis involve elaborate experimentation, development of tools, acquisition of extensive data and analysis. Never the less, the results obtained were commensurate with the efforts and have been fruitful. Of the useful results that have been obtained, to state in specific, the first is, discrimination of simulated noise sources achieved with significant success but for some overlapping which is not of major concern as far as noises are concerned. Therefore they are grouped into required number of clusters so as to achieve better classification through supervised NN. This proved to be an innovative measure in supervised classification through back propagation NN. The second is the damage characterization in CFRP specimens, which involved imaginative data processing techniques that proved their worth in terms of optimization of various training parameters and resulted in accurate identification through clustering. Labeling of clusters is made possible by marking each signal starting from clustering to final classification through supervised neural network and is achieved through phenomenological correlation combined with ultrasonic imaging. Most rewarding of all is the identification of failure modes (AE signals) mixed in noise into their respective classes. This is a direct consequence of innovative data processing, multi-class clustering and flexibility of grouping various noise signals into suitable number of clusters. Thus, the results obtained and presented in this thesis on NN approach to AE signal analysis clearly establishes the fact that methods and procedures developed can automate detection and identification of failure modes in CFRP composites under hostile environment, which could lead to the development of an in-flight monitoring system.

Η ευρύτατη χρήση του τσιμέντου οφείλεται στην χρήση του ως βασικού δομικού υλικού σε σύγχρονες κατασκευές περιλαμβανομένου και του εγκιβωτισμού επικίνδυνων στερεών ή υγρών αποβλήτων. Οι υψηλές τιμές pH και οι πολύπλοκες στερεοχημικές δομές των ένυδρων αλάτων του πυριτικού ασβεστίου (C-S-H gel) στο τσιμέντο, μπορούν να εγκλωβίσουν πολλά χημικά είδη βαρέων μετάλλων στο πλέγμα τους, καθιστώντας τα έτσι ανενεργά. Ο βαθμός σχηματισμού των ένυδρων πυριτικών αλάτων είναι επίσης, ρυθμιστικός παράγων του πορώδους, της σκληρότητας και της αντοχής του σκυροδέματος. Οι κυριότεροι τύποι του C-S-H gel που εντοπίζονται στα συστατικά του τσιμέντου είναι το πυριτικό διασβέστιο Ca2SiO4 και το πυριτικό τριασβέστιο Ca3SiO5. Εύλογα λοιπόν, η μελέτη της θερμοδυναμικής και της κινητικής σχηματισμού των αλάτων αυτών είναι πολύ σημαντική. Στην παρούσα εργασία, πραγματοποιήθηκε μελέτη της κινητικής της καταβύθισης του C-S-H gel σε υπέρκορα υδατικά διαλύματα παρασκευαζόμενα από στόκ διαλύματα Ca(NO3)2 και Na2Si3O7 σε σταθερή θερμοκρασία 25°C. Η επίδραση παραμέτρων, όπως το pH των υπέρκορων διαλυμάτων και του γραμμομοριακού λόγου των συγκεντρώσεων Ca/Si στα διαλύματα, μελετήθηκαν σε συνθήκες σταθερού pH με την προσθήκη διαλύματος NaOH από αυτόματο τιτλοδοτητή. Η κινητική ανάλυση έδειξε ότι ο μηχανισμός της ανάπτυξης των κρυσταλλικών στερεών γίνεται κυρίως με επιφανειακή διάχυση και εξαρτάται από το pH των διαλυμάτων στην περιοχή pH 10-12. Η ταυτοποίηση των ιζημάτων με τεχνικές περίθλασης ακτίνων Χ (ΧRD), υπερύθρου (FTIR) και με θερμοσταθμική ανάλυση, έδειξε τον σχηματισμό C-S-H gel με πιθανή συγκαταβύθιση άμορφης σίλικας. Το γεγονός ότι το καθορίζον την ταχύτητα στάδιο είναι η επιφανειακή διάχυση των δομικών μονάδων οδηγεί στο συμπέρασμα ότι η τροποποίηση της επιφάνειας των κρυστάλλων παρέχει την δυνατότητα ελέγχου του ρυθμού σχηματισμού του C-S-H gel και κατ’ επέκταση των ιδιοτήτων του τσιμέντου κατά την ενυδάτωσή του. Η τροποποίηση της επιφάνειας μπορεί να πραγματοποιηθεί με την βοήθεια υδατοδιαλυτών και μη χημικών ουσιών οι οποίες μπορούν να αλληλεπιδράσουν με την επιφάνεια, αλλοιώνοντας τον αριθμό και την ενεργότητα των κρυσταλλικών κέντρων ανάπτυξης. Βάσει των αποτελεσμάτων της επίδρασης της παρουσίας προσθέτων στην κινητική της καταβύθισης, πραγματοποιήθηκαν δοκιμές σε δοκίμια τσιμέντου στα οποία έγινε και εφαρμογή πολυμερών (υδατοδιαλυτών και μη) και μετρήθηκαν η υδροπερατότητα και η αντοχή τους, ιδιότητες που εξαρτώνται από τον βαθμό σχηματισμού του πυριτικού ασβεστίου. / The widespread use of cement as a building material in modern construction, including use for embedding radioactive wastes makes it a material of paramount importance. The formation of calcium silicate hydrates is of key importance for the determination of the cement characteristic properties including porosity, strength and hardness. The main types of C-S-H gel identified between cement components include di-calcium silicate Ca2SiO4 and tri-calcium silicate Ca3SiO5. Since these silicate salts during the cement hydration interact with water yielding C-S-H gel, the investigation of homogeneous precipitation of this phase is very interesting. In the present work the kinetics of spontaneous C-S-H gel precipitation in aqueous solutions was investigated at constant solution pH from supersaturated solutions at 25°C. The pH range investigated covered the range between 10-12. The effect of the solution pH and of the molar calcium:silicate ratio in the supersaturated solutions was investigated. Plots of the rates of precipitation as a function of the solution supersaturation, showed a high order dependence suggesting that the rate determining step for the precipitation of C-S-H gel was surface diffusion. The rates were found to be pH dependent in the range investigated. The precipitate was identified by powder X-ray diffraction, infrared spectrometry (FTIR) and thermogravimetric analysis as a mixture of calcium silicate hydrate gel and amorphous silica. The fact that the rate determining step was surface diffusion control, suggested that it is possible to control the rate of precipitation through surface modification, possibly treating the surface with compounds which may interact, resulting in poisoning of the active crystal growth sites. It is anticipated that control of kinetics may result in the control of the rate and of the extent of C-S-H gel formation and subsequently of the cement properties during its hydration. On the basis of the results obtained for the precipitation of C-S-H gel in the presence of additives, a series of experiments was done on cement specimens using both water soluble and compounds soluble in organic solvents. In general, the presence of the tested additives resulted in a significant reduction of water uptake suggesting, indirectly, that the formation of C-S-H gel was suppressed. Moreover the resistance to friction was reduced, possibly due to the fact that the compounds tested formed soft but impermeable to water, surface films.

Com a implementação do Programa Nacional do Álcool (Proálcool), Protocolo de Quioto e substituição do MBTE (metil-terci-butil eter) em alguns países nos últimos anos, houve um aumento significativo da produção de etanol. Os dois maiores produtores mundiais de etanol são os Estados Unidos e o Brasil, sendo o etanol oriundo do Milho e da Cana-de-açucar, respectivamente. Transporte por dutos é a forma mais econômica para grandes quantidades, porém, há evidências de que esses dutos de transporte, e também fundo de tanques de armazenamento, possam ser susceptíveis ao fenômeno de corrosão sob tensão quando operam com etanol. Este fenômeno pode ser avaliado, por exemplo, por ensaios de baixa taxa de deformação (BTD) e de tenacidade à fratura, com corpos de prova definidos em normas já conhecidas internacionalmente. Este trabalho tem por objetivo avaliar a susceptibilidade do aço API X70 em diferentes meios de etanol (Etanol combustível simulado (SFGE), Milho e Cana) através de ensaios de mecânica da fratura. Foram preparados corpos de prova pré-trincados do tipo C(T) (Compact Tension), de acordo com a norma ASTM E647-08. A análise dos resultados foi realizada através das equações da mecânica da fratura linear elástica. Nos ensaios de curvas K-R, apesar de somente o etanol de Milho apresentar uma queda de tenacidade, o K de iniciação aparente e as análises fractográficas, confirmam a fragilização do material nos meios etanol SFGE e Milho. Ensaios de baixa taxa de deformação (BTD) interrompidos e os de step loading com carga flutuante também confirmam estes resultados. / In recent years, there have been significant increases in ethanol production due to Brazilian Alcohol Program (Proálcool) implementation, Kyoto Protocol and replacement MBTE in some countries. The world’s largest producers of ethanol are United States and Brazil, being produced from Corn and Sugar Cane, correspondingly. Pipeline transportation is the most cost effective in large volumes, although, there are evidences that these pipelines and the bottom of ethanol storage tanks might be susceptible to the stress corrosion cracking phenomenon. This phenomenon can be assessed, for example, by slow strain rate tests (SSRT) and fracture toughness tests, with specimens well defined by international standards. This study aims to evaluate the susceptibility of steel API X70 in different ethanol environment (Simulated fuel-grade ethanol (SFGE), Corn and Sugar Cane) through fracture mechanics specimens. The tests were carried out on pre-cracked C(T) (Compact Tension) specimens, according to ASTM E647-08. The analysis of results was performed using linear elastic fracture mechanics equations. The analysis of K-R curves initially presented a decrease in toughness only in Corn environment, however the K for crack initiation apparent and fractography investigation confirm the material embrittlement in both SFGE and Corn ethanol environments. Tests of the slow strain rate test (SSRT) interrupted and loading step with fluctuating load also confirm these results.

[pt] Este trabalho teve como objetivo o estudo do comportamento à fratura do aço estrutural DIN 42CrMo4 através da determinação experimental de curvas de resistência (curvas R) à propagação estável de trincas. Inicialmente, conduziram-se ensaios de tração para a determinação das propriedades mecânicas do material. Os ensaios de tenacidade à fratura foram realizados em espécimes do tipo SE(B) entalhados, submetidos à flexão e com 3 geometrias distintas. Os corpos de prova foram pré-trincados por fadiga de maneira a atender a relação a/W equivalente a 0,5. Nos ensaios de propagação de trinca, adotou-se a técnica de corpo de prova único com a utilização do método das descargas parciais (Unloading Compliance Method) para a obtenção das curvas carga (P) versus deslocamento da boca do entalhe (CMOD - Crack Mouth Opening Displacement). A cada ponto de descarregamento, relacionando a inclinação da linha de carga com as medidas da flexibilidade elástica do corpo de prova, pôde-se calcular o comprimento da trinca e, consequentemente, valores do parâmetro elasto-plástico J. Em sequência, com base nos valores de J e propagação de trinca, foram levantadas as curvas R do material. Os resultados experimentais mostraram que a geometria dos corpos de prova influenciou a estabilidade da propagação das trincas durante o ensaio, sendo possível a obtenção de curvas R somente para os corpos de prova com geometria mais robusta. Além disso, percebeu-se que os valores de propagação de trinca calculados pelo método Compliance foram superestimados. / [en] This work aimed the study of the fracture behavior of the structural steel DIN 42CrMo4 through the experimental determination of resistance curves (R curves) to the stable spread of cracks. Traction tests were initially conducted to determine the mechanical properties of the material. The fracture tenacity tests were carried out in specimens of the type SE(B) notched, subjected to flexion and with 3 distinct geometries. The samples were precracked by fatigue in order to meet the a/W ratio equivalent to 0.5. In the crack propagation tests, the single specimen technique was adopted with the use of the partial discharge method for obtaining the curves load (P) versus displacement of the notch mouth (CMODCrack mouth Opening Displacement). At each point of unloading, relating the inclination of the load line with the measurements of the elastic flexibility of the sample, it was possible to calculate the length of the crack and consequently the values of the elasto-plastic parameter J. In sequence, based in the values of J and crack propagation, the R curves of the material were raised. The experimental results showed that the geometry of the specimens influenced the stability of crack propagation during the test, and it was possible to obtain R curves only for the most robust specimens. In addition, it was noticed that the crack propagation values calculated by the compliance method were overestimated.

Com a implementação do Programa Nacional do Álcool (Proálcool), Protocolo de Quioto e substituição do MBTE (metil-terci-butil eter) em alguns países nos últimos anos, houve um aumento significativo da produção de etanol. Os dois maiores produtores mundiais de etanol são os Estados Unidos e o Brasil, sendo o etanol oriundo do Milho e da Cana-de-açucar, respectivamente. Transporte por dutos é a forma mais econômica para grandes quantidades, porém, há evidências de que esses dutos de transporte, e também fundo de tanques de armazenamento, possam ser susceptíveis ao fenômeno de corrosão sob tensão quando operam com etanol. Este fenômeno pode ser avaliado, por exemplo, por ensaios de baixa taxa de deformação (BTD) e de tenacidade à fratura, com corpos de prova definidos em normas já conhecidas internacionalmente. Este trabalho tem por objetivo avaliar a susceptibilidade do aço API X70 em diferentes meios de etanol (Etanol combustível simulado (SFGE), Milho e Cana) através de ensaios de mecânica da fratura. Foram preparados corpos de prova pré-trincados do tipo C(T) (Compact Tension), de acordo com a norma ASTM E647-08. A análise dos resultados foi realizada através das equações da mecânica da fratura linear elástica. Nos ensaios de curvas K-R, apesar de somente o etanol de Milho apresentar uma queda de tenacidade, o K de iniciação aparente e as análises fractográficas, confirmam a fragilização do material nos meios etanol SFGE e Milho. Ensaios de baixa taxa de deformação (BTD) interrompidos e os de step loading com carga flutuante também confirmam estes resultados. / In recent years, there have been significant increases in ethanol production due to Brazilian Alcohol Program (Proálcool) implementation, Kyoto Protocol and replacement MBTE in some countries. The world’s largest producers of ethanol are United States and Brazil, being produced from Corn and Sugar Cane, correspondingly. Pipeline transportation is the most cost effective in large volumes, although, there are evidences that these pipelines and the bottom of ethanol storage tanks might be susceptible to the stress corrosion cracking phenomenon. This phenomenon can be assessed, for example, by slow strain rate tests (SSRT) and fracture toughness tests, with specimens well defined by international standards. This study aims to evaluate the susceptibility of steel API X70 in different ethanol environment (Simulated fuel-grade ethanol (SFGE), Corn and Sugar Cane) through fracture mechanics specimens. The tests were carried out on pre-cracked C(T) (Compact Tension) specimens, according to ASTM E647-08. The analysis of results was performed using linear elastic fracture mechanics equations. The analysis of K-R curves initially presented a decrease in toughness only in Corn environment, however the K for crack initiation apparent and fractography investigation confirm the material embrittlement in both SFGE and Corn ethanol environments. Tests of the slow strain rate test (SSRT) interrupted and loading step with fluctuating load also confirm these results.

Atualmente, um dos grandes problemas relacionados à leishmaniose é a falta de um diagnóstico específico capaz de indentificar e diferenciar espécies de Leishmania com rapidez e precisão. O desenvolvimento de métodos moleculares como a Reação em Cadeia da Polimerase (PCR), possibilita que o diagnóstico da Leishmaniose Visceral Canina (LVC) possa se tornar mais preciso e, eventualmente, de fácil execução, uma vez que limitações importantes relacionadas à sensibilidade e especificidade desta técnica ainda são descritas, principalmente quando se utiliza amostras clínicas. Com o intuito de melhor avaliar a eficiência da PCR para o diagnóstico da LVC, foram selecionadas diferentes amostras clínicas (baço, aspirado de linfonodo, pele sem lesão, pele com lesão e amostras de sangue) de 26 cães com sorologia positiva para leishmaniose submetidos à eutanásia pelo Serviço de Vigilância Epidemiológica do município de Embu das Artes - SP. Realizamos uma análise comparativa entre a PCR-RFLP kDNA-HaeIII e PCR-RFLP hsp70-BsaJI/EcoRII com dois métodos diagnósticos tradicionais (parasitológico direto, e cultura in vitro). Amostras clínicas de 28 cães com sorologia negativa para LVC da mesma região foram utilizadas como controle negativo das reações. Notamos que a PCR aprensentou maior sensibilidade em todas as amostras clínicas testadas quando comparadas aos métodos tradicionais. Os resultados apontam que a PCR-RFLP kDNA-HaeIII é a mais eficiente para o diagnóstico da LVC, com um índice de 96,15% de positividade nas amostras de pele com lesão. Quanto à discriminação da espécie de Leishmania envolvida na infecção, nossos resultados de PCR-RFLP kDNA-HaeIII indicam Leishmania chagasi-infantum como o agente etiológico envolvido na infecção e transmissão canina na cidade de Embu das Artes. Por outro lado, a análise da PCR em Tempo Real (qPCR), mostrou que algumas amostras de sangue não apresentavam o padrão associado à Leishmania chagasi-infantum, podendo indicar uma co-infecção com outras parasitoses caninas. Nosso grupo também acompanhou 184 crianças de 4 a 10 anos de idade (população de risco) residentes da mesma região de transmissão autóctone da doença canina, como também foi realizado um levantamento das espécies de flebotomíneos da região (pela SUCEN). Até o momento, não foi encontrado nenhum caso da doença humana, nem a principal espécie transmissora do parasito (Lutzomiya longipalpis). Acreditamos que esses resultados possam contribuir significativamente para aprimorar o diagnóstico e a identificação das espécies Leishmania na LVC. / Currently, one of the major problems related to leishmaniasis is the lack of a specific diagnosis capable of identifying and differentiating Leishmania species quickly and accurately. The development of molecular methods such as Polymerase Chain Reaction ( PCR ) allows the diagnosis of Canine Visceral Leishmaniasis (CVL) to become more accurate and eventually, easy to perform, since that important limitations in terms of sensitivity and specificity of this technique are being described especially when using clinical samples. In order to better evaluate the efficiency of PCR for the diagnosis of CVL, we selected different clinical samples (spleen, lymph node aspirate, skin with and without lesions and blood samples) from 26 dogs with positive serology for leishmaniasis submitted to euthanasia by the Agency of Epidemiological Surveillance of Embu das Artes - SP. Therefore, we performed a comparative analysis between the kDNAPCR-RFLP HaeIII and hsp70PCR-RFLP BsaJI/EcoRII with two traditional diagnostic methods (direct parasitological test, and in vitro culture). Additionally, clinical samples from 28 dogs with negative serology for CVL in the same region were used as negative reactions control. We noted that the PCR showed greater sensitivity in all clinical samples tested when compared with traditional methods. The results indicate that the kDNAPCR-RFLP HaeIII is the most efficient test for the diagnosis of CVL, with a positivity index of 96.15 % in skin lesions samples. Related to the discrimination of the Leishmania species involved in the infection, our results of kDNAPCR-RFLP HaeIII indicate Leishmania infantum chagasi as the agent involved in canine infection in Embu das Artes city. Moreover, the analysis of real-time PCR (qPCR) showed that some blood samples has not showed the same pattern associated with Leishmania infantum chagasi suggesting a possible co-infection with other canine parasite. Our group also followed 184 children between 4 to 10 years old (risk population) living in the same region of autochthonous transmission of canine disease, as well a survey was conducted on the sandfly species in the region (by SUCEN). So far, we found no human infection, nor the main species involved in the transmission of the parasite (Lutzomyia longipalpis). We believe that these results can significantly contribute to the improvement of the diagnosis and identification of Leishmania species involved in the CVL worldwide.

Orientador: Itamar Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-09T20:08:21Z (GMT). No. of bitstreams: 1 CamargoJunior_JoseAntoniode_M.pdf: 5956974 bytes, checksum: 439c5177de65f09b9855f932ec564537 (MD5) Previous issue date: 2007 / Resumo: Atualmente, praticamente todo o processo de desenvolvimento de componentes mecânicos que giram em alta rotação e que têm grande responsabilidade estrutural, principalmente quando fabricados em materiais de natureza frágil, como é o caso do ferro fundido, passa necessariamente por ensaios de centrifugação, que são realizados visando à determinação da rotação de ruptura. Além disso, os projetos atuais utilizam componentes com configurações geométricas que envolvem furos e outros tipos de concentradores de tensão. Em função disso, torna-se importante o conhecimento da influência de certos tipos de concentradores de tensão nesses componentes mecânicos. Este trabalho tem por objetivos determinar e analisar curvas de fator de concentração de tensão experimentais, por meio de ensaios de centrifugação, e numéricas, por meio de elementos finitos, em corpos anulares de espessura constante, submetidos à rotação e fabricados em ferro fundido cinzento perlítico GG25. Foram executados ensaios de centrifugação de cinco diferentes geometrias de corpos anulares: (a) sem concentrador de tensão; (b) com três concentradores de tensão do tipo semi-circular no raio interno; (c) com três concentradores de tensão do tipo semi-circular no raio externo; (d) com três furos passantes localizados nas proximidades do raio interno; (e) com três furos passantes localizados nas proximidades do raio externo. As tensões radial e tangencial foram determinadas por meio das equações clássicas para rotação de corpos anulares, sendo que a tensão equivalente foi determinada por meio do critério de von Mises, sendo esta comparada com o limite de resistência à tração do material determinada por meio de ensaios de tração. Foi também realizada uma análise simplificada por elementos finitos visando à determinação da tensão equivalente, também pelo critério de von Mises, para as cinco geometrias estudadas. Observou-se que cada geometria de descontinuidade geométrica apresenta um fator de concentração de tensão diferente a qual reduz a rotação de ruptura, quando comparada com o corpo anular sem concentrador de tensão. O corpo anular com concentrador de tensão do tipo semi-circular no raio interno possui os maiores níveis de fator de concentração de tensão médio, sendo este da ordem de 48% maior do que o sem concentrador. Por outro lado, o que apresentou menor nível de concentração de tensão foi o corpo anular com furos localizados nas proximidades do raio externo, sendo este da ordem de 5% maior do que o sem concentrador. Essas curvas poderão orientar o desenvolvimento de projetos de componentes mecânicos com relação aos efeitos dos concentradores de tensão analisados neste trabalho / Abstract: Currently, practically all the process of development of mechanical components working in high rotation and that they have great structural responsibility, mainly when manufactured in materials of brittle nature, as it is the case of the cast iron, passes necessarily for burst tests conducted in order to determine the burst speed. Moreover, the current projects use components with geometric configurations that involve holes and other types of stress raisers. As a function of this, the knowledge of the influence of certain types of stress raisers in these mechanical components becomes important. The objectives of this work is to determine and to analyze two types of curves of stress concentration factors, experimental, by means of the burst tests, and numerical, by means of finite element method, in annular specimens of constant thickness, submitted to rotation, and manufactured in perlitic gray iron GG25. Burst tests of five different shapes of annular specimens had been executed: (a) without stress raiser; (b) with three stress raisers of half-circular shape located in the internal radius; (c) with three stress raisers of halfcircular shape located in the external radius; (d) with three stress raisers of passing holes located near the internal radius; (e) with three stress raisers of passing holes located near the external radius. The radial and tangential stresses had been determined by means of the classic equations for rotation of annular bodies, the equivalent stress was determined by means of the von Mises criterion, and this was compared with the tensile strength of the material determined from tensile tests. Also a simplified analysis of finite element method was conducted in order to determine the equivalent stress, also by using von Mises criterion, for the five studied geometry. It was observed that each shape of geometry discontinuity presents a different stress concentration factor which reduces the rupture rotation, when compared with the annular specimen without stress raiser. The annular specimen with stress raiser of the half-circular type in the internal radius posses the biggest level of average stress concentration factor, about 48% greater of that without stress raiser. On the other hand, the annular specimen with three holes near the external radius presented minor level of stress concentration, about 5% greater of that without stress raiser. These curves will be able to guide the development of projects of mechanical components with regard to the effect of the analyzed stress concentrators in this work / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

Com a implementação do Programa Nacional do Álcool (Proálcool), Protocolo de Quioto e substituição do MBTE (metil-terci-butil eter) em alguns países nos últimos anos, houve um aumento significativo da produção de etanol. Os dois maiores produtores mundiais de etanol são os Estados Unidos e o Brasil, sendo o etanol oriundo do Milho e da Cana-de-açucar, respectivamente. Transporte por dutos é a forma mais econômica para grandes quantidades, porém, há evidências de que esses dutos de transporte, e também fundo de tanques de armazenamento, possam ser susceptíveis ao fenômeno de corrosão sob tensão quando operam com etanol. Este fenômeno pode ser avaliado, por exemplo, por ensaios de baixa taxa de deformação (BTD) e de tenacidade à fratura, com corpos de prova definidos em normas já conhecidas internacionalmente. Este trabalho tem por objetivo avaliar a susceptibilidade do aço API X70 em diferentes meios de etanol (Etanol combustível simulado (SFGE), Milho e Cana) através de ensaios de mecânica da fratura. Foram preparados corpos de prova pré-trincados do tipo C(T) (Compact Tension), de acordo com a norma ASTM E647-08. A análise dos resultados foi realizada através das equações da mecânica da fratura linear elástica. Nos ensaios de curvas K-R, apesar de somente o etanol de Milho apresentar uma queda de tenacidade, o K de iniciação aparente e as análises fractográficas, confirmam a fragilização do material nos meios etanol SFGE e Milho. Ensaios de baixa taxa de deformação (BTD) interrompidos e os de step loading com carga flutuante também confirmam estes resultados. / In recent years, there have been significant increases in ethanol production due to Brazilian Alcohol Program (Proálcool) implementation, Kyoto Protocol and replacement MBTE in some countries. The world’s largest producers of ethanol are United States and Brazil, being produced from Corn and Sugar Cane, correspondingly. Pipeline transportation is the most cost effective in large volumes, although, there are evidences that these pipelines and the bottom of ethanol storage tanks might be susceptible to the stress corrosion cracking phenomenon. This phenomenon can be assessed, for example, by slow strain rate tests (SSRT) and fracture toughness tests, with specimens well defined by international standards. This study aims to evaluate the susceptibility of steel API X70 in different ethanol environment (Simulated fuel-grade ethanol (SFGE), Corn and Sugar Cane) through fracture mechanics specimens. The tests were carried out on pre-cracked C(T) (Compact Tension) specimens, according to ASTM E647-08. The analysis of results was performed using linear elastic fracture mechanics equations. The analysis of K-R curves initially presented a decrease in toughness only in Corn environment, however the K for crack initiation apparent and fractography investigation confirm the material embrittlement in both SFGE and Corn ethanol environments. Tests of the slow strain rate test (SSRT) interrupted and loading step with fluctuating load also confirm these results.

Orientador: Itamar Ferreira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-06T11:42:58Z (GMT). No. of bitstreams: 1 AguirreTorrico_IvanFelix_D.pdf: 3675970 bytes, checksum: 89da868d1276d05e3f5f216b82efb029 (MD5) Previous issue date: 2006 / Resumo: O gasoduto Bolívia-Brasil foi fabricado com dutos de aços API 5L X65 e X70. Existem relatos na literatura especializada de que o campo de tensões nas vizinhanças da ponta da trinca e a tenacidade à fratura são similares entre os corpos de prova não normalizados do tipo tração com entalhe lateral [SE(T)] e dutos. Neste trabalho realizou-se um estudo numérico e experimental da tenacidade à fratura em condições elasto-plásticas, com corpos de prova do tipo SE(T), dos aços API 5L X65 e API 5L X70. A determinação dos parâmetros da mecânica da fratura elástica linear foi feita pelos Métodos dos Elementos Finitos (MEF) e dos Elementos de Contorno (MEC) e a determinação do parâmetro elasto-plástico integral J por MEF. O fator eta plástico obtido numericamente, pelo MEF e com dados fornecidos pelo método EPRI, foi de 1,0, para medições do deslocamento de abertura da boca da trinca (CMOD). Com este fator eta plástico, foram realizados ensaios experimentais de tenacidade à fratura com corpos de prova do tipo SE(T), com espessura de 5 mm, e esses valores foram comparados com os resultados de ensaios em corpos de prova de flexão em três pontos [SE(B)], também com espessura de 5 mm. Houve um boa concordância entre os resultados numéricos e experimentais da integral J. Verificou-se que as curvas J-R obtidas com ensaios SE(T) são próximas das obtidas com ensaios SE(B), tendo em vista que a espessura dos corpos de prova utilizada, de 5 mm, não pôde ser modelada no estado plano de tensão ou de deformação / Abstract: The gas pipeline Bolivia-Brazil was manufactured with pipes of API 5L X65 and X70 steels. Specialized literature report that the stress field in the neighborhood of the crack tip and the fracture toughness are similar between not standard single edge notch tensile specimens - SE(T) - and pipes. In this work numerical and experimental study were made of the elastic-plastic fracture toughness using SE(T) specimens for API 5L X65 and X70 steels. The determination of the parameters of the linear elastic fracture mechanics was performed by the methods of the Finite Elements (FEM) and Boundary Elements (BEM). The J-integral parameter was determined by FEM. The plastic eta factor was obtained by FEM and with data supplied by the EPRI method. In both cases for measurements of the crack mouth opening displacement (CMOD) the determined plastic eta factor is 1.0. With this plastic eta factor, experimental tests of fracture toughness were accomplished using SE(T) specimens with thickness of 5 mm, and those values were compared with the test results obtained with standard single edge bend -SE (B)- specimens also with thickness of 5 mm. There was a good agreement between the numeric and experimental results of J-integral. Was verified that the J-R curves obtained with SE(T) specimens are close to the obtained with SE(B) specimens / Doutorado / Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica