Thesis (Ph. D.)--Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 2006. / Carter, W. Brent, Committee Member ; Cook, Fred, Committee Member ; Griffin, Anselm, Committee Member ; Michielsen, Stephen, Committee Chair ; Beckham, Haskell, Committee Member ; Bottomley, Lawrence, Committee Member.

Thesis (M. S.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2007. / Koros, William, Committee Member ; Hsieh, Jeffery, Committee Chair ; Deng, Yulin, Committee Member.

Thesis (M.S.)--Brigham Young University. Dept. of Technology, 2004. / Includes bibliographical references (p. 191-195).

Thesis (Ph. D.)--Drexel University, 2007. / Includes abstract and vita. Includes bibliographical references (leaves 182-184).

Thesis (M.E.)--University of Canterbury, 2006. / Typescript (photocopy). "August 2006." Includes bibliographical references. Also available via the World Wide Web.

Thesis (doctoral)--Swedish University of Agricultural Sciences, 2003. / Thesis documentation sheet inserted. Appendix reprints four papers and manuscripts, one co-authored with Bengt Persson. Includes bibliographical references. Also issued electronically via World Wide Web in PDF format; online version lacks appendix.

Το θέμα το οποίο πραγματεύεται η παρούσα διπλωματική είναι οι αισθητήρες οπτικών ινών με φράγματα Bragg προσδιορίζοντας τον δείκτη διάθλασης του περιβάλλοντος υγρού κατά τη βύθιση του οπτικού αισθητήρα μέσα σε αυτό. Στο πρώτο κεφάλαιο θα γίνει αρχικά μια ανάλυση των οπτικών ινών αφού θα αναφερθούν ο τρόπος λειτουργίας τους, οι τύποι οπτικών ινών που υπάρχουν, πλεονεκτήματα και μειονεκτήματα που παρουσιάζουν αλλά και ο λόγος που οδηγήθηκε η τεχνολογία στην κατασκευή τους. Στο δεύτερο κεφάλαιο περιγράφονται τα γενικά χαρακτηριστικά, δηλαδή ο τρόπος κατασκευής καθώς επίσης και ο τρόπος λειτουργίας των φραγμάτων Bragg. Αναφέρονται τα διάφορα είδη φραγμάτων Bragg που υπάρχουν και οι μηχανισμοί φωτοευαισθησίας τους. Στο τρίτο κεφάλαιο δίνεται έμφαση στη χρήση των φραγμάτων Bragg σαν αισθητήρες ταυτοποίησης της φύσης των υγρών στα οποία εισάγονται οι αισθητήρες αλλά και σαν αισθητήρες μέτρησης στάθμης υγρών. Τα φράγματα Bragg χρησιμοποιούνται ευρέως και σαν αισθητήρες πίεσης, θερμοκρασίας, ροής, μετατόπισης στάθμης υγρών, χημικής ταυτοποίησης, PH, ηλεκτρικών πεδίων, μαγνητικών πεδίων καθώς και άλλων φυσικών μεγεθών. Ακόμα γίνεται μια περιγραφή της διαδικασίας χημικής απογύμνωσης (etching), καθώς επίσης και τα τεχνικά χαρακτηριστικά και τρόπους λειτουργίας της πηγής φωτός που χρησιμοποιήθηκε, η οποία είναι ένας ενισχυτής Erbium Doped Fiber Amplifier –EDFA. Το τέταρτο κεφάλαιο πραγματεύεται τα αποτελέσματα των προσομοιώσεων που έγιναν με τη χρήση του προγράμματος COMSOL Multiphysics 4.2. Οι προσομοιώσεις έγιναν για διαφορετικές τιμές δεικτών διάθλασης μιας ποικιλίας υγρών. Στο πέμπτο κεφάλαιο αναλύεται το πειραματικό μέρος της ειδικής ερευνητικής εργασίας. Παρουσιάζονται η πειραματική διάταξη και τα πειραματικά δεδομένα που ελήφθησαν στο εργαστήριο Laser, καθώς επίσης και τα σχετικά σχόλια σύγκρισης με τα αποτελέσματα των αντίστοιχων προσομοιώσεων που έγιναν. / -

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Os autores têm como objetivo, investigar a matriz extra celular, musculatura lisa e densidade vascular do prepúcio de pacientes tabagistas. Espécimes de prepúcio foram obtidas de 20 jovens adultos (média de idade= 27.2) submetidos a postectomia. Dentre os pacientes analisados, um grupo (n=10) possui história prévia de tabagismo (3 to 13 maços/ano, média = 5.8 3.2), e outro grupo (n=10) formam o grupo controle, não fumantes. A coloração de Tricrômico Masson foi utilizada para quantificar tecido conectivo, musculatura lisa e vasos. A coloração Resorcina-fucsina de Weigert foi utilizada para estabelecer as fibras do sistema elástico e a coloração, Vermelho de Picrosirius para o estudo do colágeno. O estudo estereológico foi realizado utilizando o software Image J, para determinar as densidades volumétricas. Para a análise bioquímica o colágeno total foi determinado em &#956;g de hidroxiprolina por MG de tecido seco. O estudo estatístico foi realizado lançando mão do t-teste (p<0,05). Fibras do sistema elástico de fumantes apresentaram-se aumentadas em 42.5% quando comparado ao grupo controle (p=0,002). Em contraste, musculatura lisa (p=0,42) e densidade vascular (p=0,16) não mostraram nenhuma diferença estatística. Foi realizado uma análise quantitativa utilizando Vermelho de Picrosirius sob luz polarizada, que evidenciou a presença de colágeno tipo I e III, sem diferença estatisticamente significativa. A concentração total do colágeno não mostrou diferença entre tabagistas e o grupo controle. (73.1&#956;g/mg 8.0 vs. 69.2&#956;g/mg 5.9, respectivamente, p=0,23). Tabagismo está associado a um significante aumento de fibras do sistema elástico do tecido prepucial. Estes resultados podem, possivelmente, explicar os altos índices de falha na uretroplastia peniana, com uso de flap de prepúcio em fumantes / It has been speculated by McAninch et al. (1), that smokers might experience worse results after urethral reconstruction. We decided to investigate the extracellular matrix, smooth muscle and vascular density in the foreskin of smoker patients. Foreskin samples were obtained from 20 young adults (ranging in age from 23 to 36 years; mean SD = 27.2 5.8) submitted to circumcision from July 2008 to October 2009. Of the patients analyzed, one group (n=10) had a previous history of chronic smoking (3 to 13 packs/year, mean = 5.8 3.2) i.e., one pack per day for 3 to 13 years. The control group was composed of 10 non-smoker patients. Foreskin samples were studied by histology and biochemistry. Means were compared using the two-tailed t-test (p<0.05). The elastic system fibers in the foreskin of smoker patients increased in 42.5% when compared to the control group. In contrast, the smooth muscle fibers, vascular density and total collagen concentration did not show any significant variation between smokers and controls. Smoking is associated with a significant increase of elastic system fibers in foreskin tissue. These results could possibly explain the high failure rate of penile urethroplasty in smokers by using foreskin flaps

Orientador: Younès Messaddeq / Banca: Sandra Helena Pulcinelli / Banca: Oscar Peitl Filho / Banca: Gael Yves Poirier / Banca: Carlos Kenichi Suzuki / Resumo: A integridade das rotas ópticas depende da confiabilidade das fibras, que é afetada pelas condições de fabricação das fibras e cabos (matérias primas empregadas na fabricação do vidro e do revestimento e processo de fabricação) e pelas condições de operação da rota (ambiente da rota óptica e as tensões aplicadas durante o lançamento e vida útil). O objetivo deste trabalho é avaliar a degradação dos materiais que compõem as fibras ópticas e as consequências das variações de seus aspectos físico-químicos nas propriedades mecânicas e ópticas das fibras. Para tal foram realizados três tipos de envelhecimento nas amostras: 1 - envelhecimento hidrotérmico (em água deionizada a 85°C por 14, 28 e 49 dias) de amostras com revestimento acrilato e de carbono; 2 - envelhecimento em campo resultante em perda de confiabilidade mecânica e óptica; e 3 - envelhecimento por passagem de 500 mW, sob raio de curvatura de 10mm durante 30 minutos em de amostras com revestimento acrilato e de carbono. Observou-se que para o primeiro método de revestimento, as amostras revestidas têm resistência mecânica mais baixa que as amostras decapadas com H2SO4 a quente, possivelmente devido à mudança local de pH ou a atividade da água na superfície vítrea, dependendo do mecanismo de degradação do revestimento: cross link ou cisão de cadeias. No segundo método de envelhecimento, para as amostras com problemas de resistência mecânica, notou-se que o problema se encontrou na formulação dos revestimentos, faltando plastificante no revestimento primário e excedendo o mesmo material no revestimento secundário. Esse efeito tornou o polímero interno menos aderido ao vidro, e o externo menos capaz de suportar as tensões mecânicas normais de utilização da fibra óptica, tornando o guia de onda menos resistente mecanicamente. / Abstract: The integrity of optic network depends on the reliability of optical fibers, affected by cable and fibers manufacture conditions (materials and process) and by the environmental use conditions (tensions applied during installation and long term use). The objective of this work is to evaluate degradation of the materials and the consequences of its physical-chemical aspects variations in the mechanical and optic properties of fibers. So, three types of aging in the samples had been carried through: 1 - hydro-thermal aging (in deionized water at 85°C for 14, 28 and 49 days) of samples with acrilate and carbon coatings; 2 - field aging resulting in loss of mechanical and optical reliability; and 3 - aging by optical power of 500 mW, under 10 observed that for the first covering method, the coated samples had lower mechanical resistance than the uncoated samples (with hot H2SO4), due to local change of pH or changes of water activity in the glass surface, depending on the degradation mechanism of the coating material: cross link or chain scission. In the second aging method, for the samples with mechanical reliability problems, we noted the problem was in the formularization of coating, where it was missing plasticizer in the primary coating and exceed in the secondary coating. This effect became internal polymer not adhered enough to the glass, and external one incapable to support the normal mechanical tensions of use of an optic fiber, causing low mechanical reliability. For the samples with problems of optical attenuation, the cause of the problem was the wrong preparation of secondary coating, evidenced by its high Tg value. / Doutor

Orientador: Jorge Luís Akasaki / Banca: Jefferson Sidney Camacho / Banca: Antonio Domingues Figueiredo / Resumo: Os tubos de concreto são utilizados em larga escala nas canalizações dos sistemas de abastecimento de água em diâmetros superiores a 400 mm, esgoto sanitário, drenagem pluvial, bueiro e travessia. Suas vantagens e aplicabilidade têm motivado diversas pesquisas sobre esse produto, dentre as quais podemos destacar a utilização de tubos de concreto reforçados com fibras de aço em substituição total da armadura. As fibras de aço quando adicionadas ao concreto melhoram algumas propriedades, tais como: tenacidade, limitação de abertura de fissuras e resistência ao impacto. A pesquisa objetiva analisar o comportamento mecânico de protótipos de tubos de concreto confeccionados com diferentes teores de adições de fibras de aço, tais como: 10 kg/m3, 15 kg/m3, 20 kg/m3, 25 kg/m3 e 30 kg/m3, em substituição total da armadura. Também foram fabricados tubos de concreto simples e armados para uma análise comparativa do comportamento mecânico entre aqueles e os tubos com fibras. Os tubos de concreto possuem 600 mm de diâmetro nominal e 1,5 m de comprimento, destinados aos sistemas de drenagem de águas pluviais. As fibras de aço utilizadas possuem fator de forma igual a 75 e apresentam as seguintes características: 60 mm de comprimento médio e 0,80 mm de diâmetro médio. Os corpos-de-prova cilíndricos foram submetidos aos ensaios: resistência à compressão axial, resistência à tração na compressão diametral, e os corpos-de- prova prismáticos foram submetidos aos ensaios de tenacidade enquanto os tubos de concreto foram submetidos aos ensaios: resistência à compressão diametral e absorção de água (amostras retiradas dos tubos após ensaio de compressão diametral). Dos ensaios realizados se destaca o ensaio de compressão diametral pelo fato... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The concrete pipe is widely used in plumbing systems in water supplying in higher diameters 400 mm, sewage, water rain drainage, storm drain and crossing. Its advantages and functions have motivated a lot of researches about this product, among them can point out used concrete pipes reinforced with steel fibers replacing the conventional framework. The steel fibers when added concrete improvement some properties, such as: flexural toughness, limitation crack width and high strain rates strength. The current text refers to a study developed to evaluate the mechanical behavior of manufactured prototypes with steel fibers added in different contents, such as: 10 kg/m3, 15 kg/m3, 20 kg/m3, 25 kg/m3 e 30 kg/m3, replacing the conventional framework. Also were manufactured simple concrete pipes and concrete pipes with framework for analysis to compare the mechanical behavior between that one and steel fibers. The pipes used have 600 mm nominal diameter and 1,5 m length, used in systems in water rain drainage. The steel fibers used have aspect ratio 75 and present characteristics: 60 mm medium length and 0,80 mm medium diameter. The circular specimens were submitted the testing for: compressive strength, tensile strength by diametrical compressive, and the rectangular specimens were submittes the testing for flexural toughness while the concrete pipes were submitted the testing for: diametrical compressive strength and absorption of water (sample retreat of pipes after the testing for diametrical compressive strength). The testing for realized to point for diametrical compressive strength because the testing for the same concrete pipe and all particular characteristics for observed. The Brazilian specification NBR 8890 (ABNT, 2007) specify the testing for diametrical compressive... (Complete abstract click electronic access below) / Mestre