Initiation of Dynamic Recrystallization of As-Cast N08028 Alloy

The use of high nickel content austenitic stainless steels (SASS) has significantly increased in the last decade. The corrosion and high fatigue resistance of these materials make them suitable for manufacturing oil country tubular goods (OCTG). SASS are processing by forging from casting conditions. Dynamic recovery (DRV) and recrystallization (DRX) of as-cast super austenitic stainless steel, N08028 Alloy, is investigated to study the refining effect from the as-cast grain structure to fully recrystallized austenite due to hot deformation. Both the critical stress and strain for the initiation of DRX are determined using the flow curves. To perform this analysis, hot compression tests are performed at temperatures between 900°C and 1250°C, and strain rates between 0.1 s-1 and 10 s-1, up to 0,8 final strain using a Gleeble®3800 thermomechanical simulator. Subsequently, the Johnson-Avrami-Mehl-Kolmogorow (JMAK) model is used to numerically fit the flow curves and consequently determine the critical strain. No critical points are seen for temperatures under 1100°C. Above this temperature, the JMAK model proves to be valid in all studied strain rates.The Authors would like to acknowledge the partial support from the Research Project “ALYMICRO microstructural and corrosion phenomena modeling analysis for casting and forging for the Alloy 28” in partnership with TECNALIA and TUBACE

Estudio de las aleaciones de Titanio Ti-Beta 21 S y Ti-6242 S

El objetivo del presente proyecto es el estudio de dos aleaciones de titanio para elevada temperatura, la aleación casi alfa Ti-6242 S y la aleación beta metaestable Ti-Beta 21S. Este estudio se enmarca dentro de un proyecto europeo en el que se pretenden desarrollar y estudiar aleaciones de titanio resistentes a elevada temperatura para la fabricación de toberas de escape de helicópteros. En el presente proyecto se incluye una descripción general de las aleaciones de titanio para después introducir las aleaciones de titanio en aplicaciones aeronáuticas y finalmente acabar en una descripción detallada de las aleaciones que se estudiarán. En este proyecto no se pretende caracterizar estas aleaciones, ya que el trabajo que ello exige se escapa del alcance de un proyecto de final de carrera, únicamente se pretende dar una descripción de dichas aleaciones así como presentar un estudio microestructural, los resultados obtenidos de propiedades a tracción a diferentes temperaturas y el comportamiento de ambas aleaciones frente a la oxidación

Estudio de las aleaciones de Titanio Ti-Beta 21 S y Ti-6242 S

El objetivo del presente proyecto es el estudio de dos aleaciones de titanio para elevada temperatura, la aleación casi alfa Ti-6242 S y la aleación beta metaestable Ti-Beta 21S. Este estudio se enmarca dentro de un proyecto europeo en el que se pretenden desarrollar y estudiar aleaciones de titanio resistentes a elevada temperatura para la fabricación de toberas de escape de helicópteros. En el presente proyecto se incluye una descripción general de las aleaciones de titanio para después introducir las aleaciones de titanio en aplicaciones aeronáuticas y finalmente acabar en una descripción detallada de las aleaciones que se estudiarán. En este proyecto no se pretende caracterizar estas aleaciones, ya que el trabajo que ello exige se escapa del alcance de un proyecto de final de carrera, únicamente se pretende dar una descripción de dichas aleaciones así como presentar un estudio microestructural, los resultados obtenidos de propiedades a tracción a diferentes temperaturas y el comportamiento de ambas aleaciones frente a la oxidación

Kahina : uma rainha berbere do século VII vista por escritoras magrebinas contemporâneas

Este trabalho visa analisar, através da narrativa de escritoras magrebinas contemporâneas, a história da rainha Kahina, que no século VII une o povo berbere (Amazigh) e resiste aos novos conquistadores, os árabes. Nesse sentido, buscou-se compreender como a história de Kahina se perpetuou na memória coletiva do Magreb e como hoje é representada como um símbolo de resistência feminina. Para isso, analisou-se escritoras magrebinas selecionadas que falaram do papel de Kahina na região e as representações da rainha através de diferentes expressões artísticas.This work aims to analyze, through the narrative of contemporary Maghreb women writers, the story of Queen Kahina, who in the 7th century unites the Berber people (Amazigh) and resists the new conquerors, the Arabs. In this sense, we tried to understand how the story of Kahina was perpetuated in the collective memory of the Maghreb and how it is today represented as a symbol of feminine resistance. For this, we studied selected Maghreb women writers who spoke about the role of Kahina in the region and the representations of the queen through different artistic expressions

Molecular characterization of the meq gene of Marek's disease viruses detected in unvaccinated backyard chickens reveals the circulation of low- and high-virulence strains

ABSTRACT Marek's disease (MD) is an important lymphoproliferative disease of chickens, caused by Gallid alphaherpesvirus 2 (GaHV-2). Outbreaks are commonly reported in commercial flocks, but also in backyard chickens. Whereas the molecular characteristics of GaHV-2 strains from the commercial poultry sector have been reported, no recent data are available for the rural sector. To fill this gap, 19 GaHV-2 strains detected in 19 Italian backyard chicken flocks during suspected MD outbreaks were molecularly characterized through an analysis of the meq gene, the major GaHV-2 oncogene. The number of four consecutive prolines (PPPP) within the proline-rich repeats of the Meq transactivation domain, the proline content, and the presence of amino acid (aa) substitutions were determined. Phylogenetic analysis was performed using the Maximum Likelihood method. Sequence analysis revealed a heterogeneous population of GaHV-2 strains circulating in Italian backyard flocks. Seven strains, detected from birds affected by classical MD, showed a unique meq isoform of 418 aa with a very high number of PPPP motifs. Molecular and clinical features are suggestive of a low oncogenic potential of these strains. The remaining 12 strains, detected from flocks experiencing acute MD, transient paralysis, or sudden death, had shorter Meq protein isoforms (298 or 339 aa) with a lower number of PPPP motifs and point mutations interrupting PPPP. These features allow us to assert the high virulence of these strains. These findings reveal the circulation of low- and high-virulence GaHV-2 strains in the Italian rural sector

Draft genome sequence of Cupriavidus UYMMa02A, a novel beta-rhizobium species

We present the draft genome of Cupriavidus UYMMa02A, a rhizobium strain isolated from root nodules of Mimosa magentea. The assembly has approximately 8.1 million bp with an average G+C of 64.1%. Symbiotic and metal-resistance genes were identified. The study of this genome will contribute to the understanding of rhizobial evolution

Molecular detection and characterization of Mycoplasma gallisepticum and Mycoplasma synoviae strains in backyard poultry in Italy

ABSTRACT Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS) represent the most important avian Mycoplasma species in the poultry industry, causing considerable economic losses. In Italy, the presence of MG or MS has been investigated especially in commercial poultry farms. To our knowledge, no systematic investigations on MG or MS presence using highly specific diagnostic assays have been performed in backyard poultry. The aim of this study was to detect and molecularly characterize MG and MS strains in 11 backyard poultry flocks located in different regions of Italy. Tracheal swabs were collected and DNA was extracted. For MS, a PCR targeting a vlhA gene fragment was performed, and typing and subtyping was attempted. The presence of MG was investigated by a screening PCR, then MG typing by gene-targeted sequencing (GTS). All the amplicons were sequenced, then MG and MS dendrograms were constructed. All the flocks examined resulted Mycoplasma positive: 5 out of 11 (45.45%) were MG and MS positive, 3 (27.27%) were MG positive, and the remaining 3 (27.27%) were MS positive. The MS detections were assigned to types C, D, and F. All strains of type D belonged to subtype D1 and 2 unknown subtypes were identified. A MS sequence showed peculiar characteristics, which did not allow assignment to a known MS type or subtype. MG GTS analysis identified 6 MG strains belonging to 5 subclusters circulating in Italian backyards chicken flocks. The results of this study provide evidence of a risk for commercial poultry farms, especially in areas where backyard and commercial farms are close, suggesting the implementation of biosecurity measures

Inovação Tecnológico-Pedagógica em Cursos de Formação de Professores

Resumo: Investigou-se como as tecnologias educacionais em rede e a convergência entre modalidades no ensino superior potencializam inovação tecnológico-pedagógica em cursos de formação de professores. Desenvolveu-se etapas de pesquisa-ação e questionários tipo survey para análise de dados. Os resultados apontam que a integração e a convergência são viáveis no ensino superior através da implementação de recursos educacionais e atividades de estudo parametrizadas pelas políticas públicas e projetos pedagógicos. Conclui-se que a integração destas tecnologias potencializa a convergência, interação e a construção da fluência tecnológico-pedagógica. Palavras-chave: Tecnologias educacionais em rede- Convergência- Inovação

Resenha

Resenha do livro "A diferença somos nós. A gestão da mudança social e as políticas educativas e sociais" de Stephen R. Stoer e António M. Magalhães

Inovação Tecnológico-Pedagógica em Cursos de Formação de Professores

Resumo: Investigou-se como as tecnologias educacionais em rede e a convergência entre modalidades no ensino superior potencializam inovação tecnológico-pedagógica em cursos de formação de professores. Desenvolveu-se etapas de pesquisa-ação e questionários tipo survey para análise de dados. Os resultados apontam que a integração e a convergência são viáveis no ensino superior através da implementação de recursos educacionais e atividades de estudo parametrizadas pelas políticas públicas e projetos pedagógicos. Conclui-se que a integração destas tecnologias potencializa a convergência, interação e a construção da fluência tecnológico-pedagógica.\ud \ud Palavras-chave: Tecnologias educacionais em rede- Convergência- Inovação