Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2016-10-21T11:41:37Z No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:38:42Z (GMT) No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-11-08T18:38:48Z (GMT) No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5) / Made available in DSpace on 2016-11-08T18:38:54Z (GMT). No. of bitstreams: 1 DissNMA.pdf: 5169564 bytes, checksum: 024c06d911b0aca7d5ad498353cc25ef (MD5) Previous issue date: 2015-11-30 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Friction Spot Joining (FSpJ) is a prize-winning joining technique for hybrid metal-polymer composite structures. This master thesis was devised to investigate the feasibility of FSpJ of metal-composite structures with additional film interlayer. Friction spot joints of aluminum alloy 2024-T3 and carbon-fiberreinforced polyphenylene sulfide laminate composite with additional PPS film interlayer were successfully produced. The highest peak temperature achieved during the joining process was 417°C. DSC analysis demonstrated that the degree of crystallinity decreased for the composite (from 22% to 12%) and increased for the PPS film (from 7% to 27%) after joining. TGA analysis indicated that no extensive thermo-mechanical degradation induced by the joining process occurred. The main bonding mechanisms of FSp joint were identified as macro- and micro-mechanical interlocking, as well as adhesion forces. The process-related microstructural effects were evaluated and correlated to the local mechanical performance of the joining parts through micro and nanohardness. Further, mechanical grinding, sandblasting and plasma activation surface pre-treatments were performed on the composite part to enhance the adhesion between the joining parts. The generated surface features due to the surface pre-treatments were correlated to the mechanical performance of the joints. Sandblasted specimens showed the best mechanical performance among the surface pre-treatments used in this work. The lap shear strength of joints with interlayer (2703 ± 114 N up to 3069 ± 166 N) was up to 55% higher than the corresponding joints without film. The fatigue life of the joints with interlayer was 4 times longer in comparison with those without interlayer; superior fatigue strength was also observed. The durability of the joints was evaluated through hydrothermal accelerated aging; the maximum reduction in initial strength was 12.4% for 28 days of aging. Finally, the failure mechanisms of the joints were discussed, demonstrating a mixture of adhesivecohesive failure mode. / A União Pontual por Fricção (FSpJ) é uma técnica internacionalmente premiada para união de estruturas híbridas metal-compósito polimérico. Esta dissertação de mestrado investigou a viabilidade técnica da produção de juntas metal-compósito com filme polimérico intermediário através do FSpJ. Juntas de alumínio 2024-T3 e laminado compósito de poli(sulfeto de fenileno) (PPS) reforçado com fibras de carbono com filme intermediário de PPS foram produzidas com sucesso. A máxima temperatura processual identificada foi de 417°C. Análises de DSC demonstraram decréscimo no grau de cristalinidade do compósito (de 22% para 12%) e acréscimo no caso do filme intermediário (de 7% para 27%) depois de submetidos ao processo de união. Análises de TGA não identificaram evidências de ocorrência de degradação termomecânica dos componentes poliméricos das juntas induzida pelo FSpJ. Os principais mecanismos de união identificados na interface das juntas foram macro- e micro-ancoramento mecânico, além de forças adesivas. As mudanças microestruturais induzidas pelo processo de união foram investigadas e correlacionadas com o desempenho mecânico local dos componentes da junta através de medidas de micro e nanodureza. Pré-tratamentos superficiais de lixamento, jateamento de areia e ativação por plasma foram realizados no componente compósito a fim de aprimorar a adesão entre os componentes a serem unidos. As superfícies pré-tratadas foram caracterizadas e suas propriedades foram correlacionadas com a resistência mecânica das juntas correspondentes. As amostras jateadas produziram juntas com a melhor resistência mecânica entre os pré-tratamentos superficiais investigados neste estudo. A resistência ao cisalhamento das juntas com filme (2703 ± 114 N até 3069 ± 166 N) apresentou-se até 55% superior à resistência das respectivas juntas sem filme. A vida em fadiga das juntas com filme apresentou-se cerca de 4 vezes mais longa em comparação às juntas sem filme. A durabilidade das juntas foi investigada através de envelhecimento hidrotérmico acelerado, sendo que a máxima redução em resistência ao cisalhamento foi de 12,4% para 28 dias de envelhecimento. Finalmente, os mecanismos de falha das juntas foram discutidos, demonstrando a predominância do modo coesivo de falha.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-08-20T14:30:04Z No. of bitstreams: 1 Dissertação - Paula Caroline Camargo Pastório.pdf: 1015013 bytes, checksum: 55f5feb2d1dc414b52a7b3a9856da458 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-24T20:01:43Z (GMT) No. of bitstreams: 1 Dissertação - Paula Caroline Camargo Pastório.pdf: 1015013 bytes, checksum: 55f5feb2d1dc414b52a7b3a9856da458 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-08-24T20:06:02Z (GMT) No. of bitstreams: 1 Dissertação - Paula Caroline Camargo Pastório.pdf: 1015013 bytes, checksum: 55f5feb2d1dc414b52a7b3a9856da458 (MD5) / Made available in DSpace on 2015-08-24T20:06:02Z (GMT). No. of bitstreams: 1 Dissertação - Paula Caroline Camargo Pastório.pdf: 1015013 bytes, checksum: 55f5feb2d1dc414b52a7b3a9856da458 (MD5) Previous issue date: 2014-06-06 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / The purpose of this study was identify the response of blood properties and glycogen content in tissues of neonates and juveniles of cururu stingray (Potamotrygon cf. histrix) exposed to progressive decay of dissolved oxygen levels in water (hypoxia). Individuals of cururu stingrays were subjected to three groups: normoxia (NO) where animals were kept in O2 levels up to 80% O2 saturation (about 6.0 mg/L) and two groups exposed to progressive hypoxia, where O2 levels declined (until at least 1 mg/L) by own respiration, hypoxia with access to the surface (HC), where the stingrays had free access to the entire water column, and hypoxia without access to the surface (HS), where a containment screen was installed 5 cm below the surface to prevent animals had access to more oxygenated layer of the water column. Six individuals were used in each treatment, in both experiments with neonates and juveniles. We evaluated the frequency of spiracular movements (FE), which increased in response to hypoxia in both neonates (39 to 74 beats/min) and juveniles (50 to 78 beats/min); hematological parameters, which showed more pronounced responses in neonates, as decreased erythrocyte count and increased in MCH in HS group and increased in MCV on both HC and HS groups. Regarding plasma metabolites, there was an increase in lactate levels in the HC group of juveniles, decreased total cholesterol in neonates and juveniles, and in both treatment groups, as well as increased levels of total protein in HS group of juveniles. In juveniles, increased liver glycogen and muscle glycogen mobilization (more intense in the HC group) were observed in response to progressive hypoxia. However, this pattern was not observed in neonates who showed differences in liver glycogen between groups exposed to hypoxia, but not when compared to normoxic group. Also, similar levels of this sugar in the muscle were observed in the three treatment groups. Neonates and juveniles of Potamotrygon cf. histrix share characteristics observed in other hypoxia-tolerant fish, such as increased gill/espiracular frequency in response to low oxygen levels; their large glycogen reserves (muscle and liver); the ability to adjust some parameters of metabolism, such as hematology, that in the case of cururu stingray occurs in the early stages of life, and increases in circulating lactate levels as a result of activation of anaerobic metabolism. It is concluded that this freshwater stingray species can be inserted in the group of hypoxia-tolerant animals. / Este estudo teve como objetivo verificar a resposta das propriedades do sangue e das reservas de glicogênio em tecidos de indivíduos neonatos e juvenis da arraia cururu (Potamotrygon cf. histrix) frente à diminuição progressiva dos níveis de oxigênio dissolvido na água (hipóxia). Para isso, indivíduos neonatos e juvenis da espécie foram submetidos a três tratamentos distintos: grupo de animais mantidos em normóxia (NO), em concentrações de O2 em torno de 80% de saturação (~6,0 mg/L) e dois grupos expostos à hipóxia gradual, nos quais os níveis de O2 decaíram (até pelo menos 1 mg/L) pela respiração da própria arraia, sendo hipóxia com acesso à superfície (HC), onde as arraias tinham acesso livre a toda coluna d’água, e hipóxia sem acesso à superfície (HS). Nos aquários deste último grupo foram instaladas telas plásticas 5 cm abaixo da superfície, para impedir que os animais tivessem acesso à camada mais oxigenada da coluna d´água. Seis indivíduos foram utilizados em cada tratamento, tanto no experimento com neonatos quanto com juvenis. Foi avaliada a frequência espiracular (FE), que aumentou em resposta à hipóxia em ambos, neonatos (39 para 74 beats/min) e juvenis (50 para 78 beats/min); os parâmetros hematológicos, que mostraram respostas mais evidentes nos neonatos, com diminuição da contagem de eritrócitos e aumento do HCM no grupo HS e aumento do VCM em ambos os grupos HC e HS. Quanto os metabólitos plasmáticos, houve aumento nos níveis de lactato no grupo HC dos juvenis, diminuição do colesterol total em neonatos e juvenis e, em ambos os tratamentos, além de aumento dos níveis de proteínas totais no grupo HS dos juvenis. Nos juvenis, foi observado aumento do glicogênio hepático e mobilização do glicogênio muscular (mais intenso no grupo HC) em resposta à hipóxia gradual. No entanto, esse padrão não foi observado nos neonatos, que mostraram diferenças no glicogênio hepático entre os grupos expostos à hipóxia, mas não em relação ao grupo mantido em normóxia e níveis similares deste açúcar no músculo nos três tratamentos. Neonatos e juvenis de Potamotrygon cf. histrix compartilham características observadas em outros peixes tolerantes à hipóxia, como o aumento da frequência branquial/espiracular em resposta a níveis baixos de oxigênio; o fato de possuírem grandes reservas de glicogênio tecidual (hepático e muscular); a capacidade de ajuste de alguns parâmetros do metabolismo, como a hematologia, que no caso da arraia cururu ocorre nas primeiras fases de vida, e aumentos dos níveis circulantes de lactato, como resultado da ativação do metabolismo anaeróbico. Conclui-se então que essa espécie de arraia de água doce está inserida no grupo dos animais tolerantes à hipóxia.

L’objectif de cette étude est d'évaluer la qualité de l'eau dans le basin inférieur du Litani (sud Liban) et d’évaluer son potentiel d'utilisation polyvalente comme une des solutions aux problèmes aggravés d’eau au Liban. Pour identifier les sources possibles de métaux et ensuite caractériser le comportement chimique de ces métaux dans l'eau et dans les sédiments, des échantillons d’eau et des sédiments ont été prélevés de six sites représentatifs. Ils ont été analysés durant les trois saisons de l'année 2011-2012 (c'est-à-dire pluvieuse, mi- pluvieuse et sèche). L’ACP (l'analyse en composante principale), a ensuite été utilisé pour interpréter les concentrations dans l'eau fluviale. Les résultats montrent que parmi les 18 variables, qui ont été évaluées pour Caractériser les propriétés physico-chimiques, il y en a 4) Fe, NO2, CaCO3, Cu) qui permettent de qualifier le type d'environnement étudié; trois groupes ont été identifiés et différenciés par ACP selon les saisons. Le premier groupe inclut toutes les spécificités du milieu en saison pluviale et montre des concentrations importantes en Fe et NO2 et faibles en NH4. Le deuxième groupe est formé par les échantillons prélevés lors de la saison sèche et montre des caractéristiques physicochimiques opposés à celles observées dans le premier groupe. Enfin, le troisième groupe regroupe les observations de la saison mi- pluvieuse caractérisée par des concentrations faible en K+, PO43-et le Cl-. Les résultats montrent que les concentrations de Pb, Fe sont élevées sur deux sites avec dans un cas des valeurs de Cr et Ni importantes, Les sédiments ont été caractérisés par différentes techniques comme la capacité d'échange de cations, la granulométrie, la diffraction des rayons X (XRD) et la spectroscopie infrarouge à transformée de Fourier (FTIR). L'analyse FTIIR montre que la quantité de la montmorillonite est plus faible que la kaolinite et beaucoup inférieure que le quartz et la calcite. La corrélation de Pearson a été également effectuée dans cette étude pour comparer et déterminer la relation entre les métaux lourds dans les sédiments. L’indice de Géo accumulation (Igeo) , le facteur de Contamination (Cf), et le degré de contamination (Cd) ont été également déterminés pour évaluer le niveau de contamination dans les sites. Les valeurs obtenus montrent que les concentrations de Pb et de Fe sont élevés dans les deux sites et la valeur de Cr, Ni, sont élevés dans un seul site. Ces résultats suggèrent qu'une attention particulière doit être accordée à la question remobilisation des éléments, car une grande partie des éléments dans les sédiments sont susceptibles de se libérer dans l'eau. Tous les sites sont caractérisés par modérées à très polluée microbienne, nous avons encore observé que le dégrée de contamination a augmenté durant la saison sèche. Cependant, aucune pollution critique n'a été rapportée dans cette partie de la rivière ; sauf la haute concentration de Fe et NO2-dans tous les sites examinés en raison des rejets d'eaux usées et l'activité touristique dans le LLRB, les Concentrations de sept métaux lourds (Cu, Fe, Cd, Mn, Cr, Zn, Ni et Pb) dans les sédiments ont été déterminés pour évaluer leurs niveaux et leurs distribution spatiale / The objective of this study was to evaluate water quality of the lower Litani River and assess its feasibility for multi-purpose usage as one of the solutions to the aggravated water problems in Lebanon, To identify possible sources of metals (i.e. geological and/or anthropogenic) and then to characterize the chemical behavior of these metals in water and bed sediments, water and bed load sediments were sampled at six representatives sites which are investigated over three seasons of the year 2011-2012 (i.e. rainy, mid-rainy and dry seasons), The PCA (principal component analysis) method was used to interpret the elemental concentrations in the river water. Results show that among 18 variables, which were evaluated to characterize their physic-chemistry and metals, there are only 4 (Fe, NO2-, CaCO3, Cu) that were determined the type of environmental studied; Three groups were identified and differentiated by PCA according to the seasons. The first group includes all statements made in the mid rainy season and has a dialogue rich in Fe and NO2, and low in NH4 and EC. The second group formed in dry season, and surveys show physicochemical characteristics opposite to those in the first group, the third group formed in mid rainy, and showed the low concentration of K+, PO43- and Cl-. Sediments were characterized by a set of cations exchange capacity, granulometric, diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR( The FTIR analysis shows that the amount of montomorillonite is less than kaolinite and very much less than quartz and calcite. Pearson’s correlation was also performed in this study to compare to and determine the correlation between heavy metals in the sediments. Geo-accumulation (Igeo) index, Contamination Factor (Cf), and contamination degree (Cd) were also applying to assess the level of contamination in the sites. The results shows that the concentration of Pb, Fe are high in the site S5, S6 and the value of Cr ,Ni, are high in the S6, this results suggest that special attention must be given to the issue of element re-mobilization, because a large portion of elements in sediments are likely to release back into the water column. All the sites are characterized by moderate to highly microbial polluted range. The degree of contamination was increased in dry season. However, no critical physicochemical pollution has been reported in this part of the river; except the high concentration of Fe and NO2- in all investigated sites due to the reject of wastewater and to the distribution of touristic activities in the LLRB, the Concentrations of seven heavy metals is high(Cu, Fe, Cd , Mn , Cr, Zn, Ni and Pb) for sediment is higher according to Consensus-based sediment quality guidelines of Wisconsin (Wisconsin Department of Natural Resources, 2003) were applied to assess metal contamination in sediment

The master thesis focuses on design of fully-differential frequency filters with modern active components in current mode. First part informs about problems concerning analogue frequency filters and creating differential structures. Second part deals with methods of create filters and used active components - DACA (Digital Adjustable Current Amplifier) and MO-CF (Multiple Output Current Follower). Own design of differential filters is divided on two parts. In the first part of design results there are filters created with synthetic higher-order elements. There are presented circuit structures implementing the third order low pass filter and high pass filter. In the second part are designed filters with signal flow graphs. The first circuit implementing low pass, high pass, band pass, band rejection and all-pass filter. The second circuit is with help of the same set of current amplification by DACA components tuning of the natural frequency. For this circuit was make sensitivity analysis. In the final part is practical implementation of the differential frequency filter for tuning of the natural frequency and summarises the thesis.

No description available.

Studies have shown that accuracy of L2 writing is improved when teachers employ direct corrective feedback (CF). Less is known about the benefits of adding some form of metalinguistic explanation to the focused direct CF. In this study, thirty-six grade nine students from two different schools in Sweden completed two sets of written tasks, one week apart. All of the students’ work was corrected using focused direct CF, with only one linguistic feature (the accurate use of the present simple and the present continuous) being the primary focus. Some of the students also received an oral metalinguistic explanation in the form of a class lecture, while others received a written, personalised metalinguistic explanation. Eleven students were subsequently interviewed.The study showed that all of the students appreciated the CF that they received and the vast majority thought that it had helped them, even if their results did not reflect this. The students who received focused direct corrective feedback with an oral explanation in the form of a class lecture showed the most consistent improvement overall.

Corrective feedback (CF) is regarded as a controversial topic when it comes to writing in the L2 classroom. Some researchers have found it to be both meaningless and harmful, while others have researched the effects of different types of CF and found it to be good for language development in several ways. This made us interested in conducting a study focusing on what attitudes grade 3-5 (age 9-11) teachers have concerning CF, and if they themselves use it for their L2 students’ writing. The study was conducted through five semi-structured interviews with teachers working in Lund, Sweden. The aim of the study was to investigate compulsory school teachers’ experiences of and thoughts on CF as a teaching method for improving young L2 learners’ writing. The results revealed that the teachers believe CF to be an irreplaceable part of language learning but that it should be adapted to each individual’s needs. Although all interviewed teachers acknowledged CF’s potential harm on learners’ motivation and willingness to write, no one believed that it could be left out completely.

Cystic fibrosis (CF) is an autosomal recessive genetic disorder involving a mutation in the CF transmembrane conductance regulator protein (CFTR), which causes dysfunctional transport of chloride ions across cell membranes. CF affects multiple body systems and a few of its symptoms include chronic cough, difficulty breathing, obstructive airway disease, bacterial pulmonary infections, maldigestion, malabsorption, pancreatitis, and male infertility. Until recently, treatment options have been limited to alleviating symptoms, but a new classification of drugs, CFTR modulators, provide an opportunity to slow the progression of the disease and improve clinical outcomes. The effect of CFTR modulators may be attributed to the reduction of persistently colonizing bacteria in CF lungs. Though, the effects of modulators on microbial communities colonizing the CF lung remains unknown, specifically with common respiratory pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. Particularly, previous CF studies have been limited in scope due to focusing on only one type of modulator and by using low-yield sequencing techniques. To address this gap, we seek to study the changes in CF respiratory pathogens of patients initiating CFTR modulator therapy at Nemours Hospital using long-read metagenomic sequencing (Oxford Nanopore) of longitudinally collected respiratory samples. We have optimized a protocol for host DNA depletion and microbial metagenomic sequencing to characterize the respiratory microbiome. This study focuses on utilizing these sequencing data to compare the microbiome among two healthy controls to pre-CFTR-treatment microbial communities of two recruited pediatric CF patients.

No description available.

No description available.