Creep analysis of a GRP cylinder under hydrostatic test / Análise de fluência de um cilindro GRP sob teste hidrostático

The GRP (Glass Reinforced Polymer) has been widely used in several industrial applications mainly due to its low cost, high availability, and easy manufacturing process. The matrix made by a combination of glass fibers and epoxy offers good engineering properties for the composite material. This study aims to investigate the creep behavior of a glass fiber/epoxy composite cylinder when it was subjected to hydrostatic pressure at room temperature, and when heated at 50ºC. The geometrical viscoelastic deformation was identified by processing signal data positioned on the cylinder surface. Then, electronic data processing was performed to obtain the characteristic of the creep phase phenomenon attributed to this polymeric composite. The cylindrical specimen has been manufactured using a 4-axis CNC (Computer Numeric Control) filament winding machine, which is equipment designed to produce cylindrical components in the composite industry. A creep test was performed by submitting the cylinder to a hydrostatic load for 500 hours, with a controlled injection of fluid up to a 50 bar pressure. Moreover, fiber volume fraction and composite density were determined to control de manufacturing parameters. The results showed that the glass transition temperature of the composite was 120°C. This also indicated a high level of reliability in the manufacturing parameters of the composite specimen. In the experiment carried out at 50ºC, the polymer matrix showed a loss of stiffness, which contributed to increased strain levels in the composite material. The structure did not show a significant creep effect after 500 hours, ensuring good dimensional and structural stability from the cylinder. Once the creep test finished, the cylinder was submitted to increase the pressure level to rupture. The microstructure was also evaluated using scanning electron microscopy (SEM). The SEM analyses presented a good agreement with the filament winding manufacturing parameters and showed the excellent quality of impregnation between glass fiber and epoxy resin applied on the cylinder specimen. The images presented evidence of an excellent adhesion of the fiber into the matrix, contributing to a good performance of the composite

Influence of electron beam irradiation on the mechanical properties of pbat/pla polymeric blend / Influência da irradiação por feixe de electrões nas propriedades mecânicas da mistura polimérica pbat/pla

The aim of this research was to evaluate the changes in the mechanical properties of poly(butylene adipate co-terephthalate)/poly(lactic acid) (PBAT/PLA) polymeric blend after the radiation process at different radiation doses. The irradiation was performed in an electron beam accelerator, with 1.5 MeV of energy and 25 mA electric current. The samples were irradiated with doses of 5, 10, 15, 25, 50, 65 and 80 kGy. Both irradiated and non-irradiated samples were characterized by Izod pendulum impact resistance and tensile strength at rupture. The results showed an increase of 44% in relation to Izod impact resistance at a dose of 65 kGy. However, the module of elasticity decreased 56% and tensile strength at rupture decreased 55% at the same radiation dose. In relation to elongation, significant alterations caused by electron beam irradiation was not observed. Therefore, it can be concluded that irradiated blends could be used to make environmentally friendly products, which could absorb impact energy.

Influence of electron beam irradiation on the mechanical properties of PBAT/PLA polymeric blend / Influência da irradiação do feixe de elétron nas propriedades mecânicas da mistura polimérica PBAT/PLA

The aim of this research was to evaluate the changes in the mechanical properties of poly(butylene adipate co-terephthalate)/poly(lactic acid) (PBAT/PLA) polymeric blend after the radiation process at different radiation doses. The irradiation was performed in an electron beam accelerator, with 1.5 MeV of energy and 25 mA electric current. The samples were irradiated with doses of 5, 10, 15, 25, 50, 65 and 80 kGy. Both irradiated and non-irradiated samples were characterized by Izod pendulum impact resistance and tensile strength at rupture. The results showed an increase of 44% in relation to Izod impact resistance at a dose of 65 kGy. However, the module of elasticity decreased 56% and tensile strength at rupture decreased 55% at the same radiation dose. In relation to elongation, significant alterations caused by electron beam irradiation was not observed. Therefore, it can be concluded that irradiated blends could be used to make environmentally friendly products, which could absorb impact energy. 

Fatores associados ao consumo de álcool e drogas entre estudantes universitários

OBJECTIVE: Recent studies show an alarming rate of alcohol and drug use among university students. The objective of this study was to assess the level of association between lifestyle and socioeconomic status and the prevalence of alcohol, tobacco, medicine, and "illicit drug" use in the last 12 months among university students. METHODS: The sample included 926 undergraduate students in the Biology Department of a university in São Paulo who completed an anonymous, self-applied questionnaire in 2000 and 2001. Anova and Chi-square tests were applied to verify the correlation between substance use and variables. RESULTS: Among students who reported having a religion, alcohol consumption was 83.1%, tobacco use 20.7%, and "illicit drugs" 24.6% during this period. Among students who reported not having a religion, reported alcohol use was higher in the last 12 months: alcohol (89.3%), tobacco (27.7%) and "illicit drugs" (37.7%). Monthly family income was related to alcohol and "illicit drug" use (pOBJETIVO: Estudos recentes mostram o uso preocupante de álcool e drogas entre universitários. O objetivo do trabalho foi verificar o grau de associação entre o estilo de vida e situação socioeconômica e o uso de álcool, tabaco, medicamentos e "drogas ilícitas" nos últimos 12 meses entre universitários. MÉTODOS: A amostra compreendeu 926 alunos da área de Ciências Biológicas de uma universidade do Município de São Paulo, os quais responderam a questionário anônimo e de auto-preenchimento em 2000 e 2001. Foram utilizados os testes de análise de variância e qui-quadrado para verificar a correlação entre o uso de substâncias e as variáveis estudadas. RESULTADOS: Entre os alunos com alguma religião, o consumo de álcool foi de 83,1%, o de tabaco, 20,7% e o de "drogas ilícitas", 24,6%, nesse período. Entre os alunos que não possuíam religião, o consumo nas três categorias foi superior nos últimos 12 meses: álcool (89,3%), tabaco (27,7%) e "drogas ilícitas" (37,7%). A renda familiar mensal mostrou-se relacionada ao uso de álcool e "drogas ilícitas" (

Análise de esteiras microbianas e cianobactérias da laguna Amarga, Parque Nacional de Torres del Paine, Chile

This study is based on cyanobacterial and sedimentary investigations of the microbial mats formed at Laguna Amarga, located at the southernmost part of South America, specifically in the Chilean Torres del Paine National Park. The Torres del Paine’s natural and geological richness is composed by large extensions of native forests, lakes, fjords and millenary glaciers presided by Paine range and Patagonian Andes. It was created in 1959 and declared Biosphere World Reserve by UNESCO in 1978. In the area, it is common to observe Late Jurassic, Cretaceous and Miocene outcrops with glacial lineations evidencing the ice retreat. The Laguna Amarga is a shallow lake with a basin area of 3,18 km2 and the habitat for extensive colonies of algae and microbial mats. On the eastern shore stromatolites with nodular, bulbous, stratiform and domal forms are found. Analyses of the microbial mats allowed the identification of 25 species of cyanobacteria. The families Synechococcaceae Anagnostidis & Komárek 1995 (32%) and Chroococcaceae Nägeli 1849 (32%) were de most frequent in the material. The microbial mats of this lake may be produced mainly by the spherical cyanobacteria. The formation of microbial mats is controlled by the high frequency of cyanobacteria and by environmental factors. The correct interpretation of the microbial mats and their features and also the environmental conditions where they are formed are important to understand analogous structures in the past and could be applied in the interpretation of ancient microbial mats. Key words: hypersaline lagoon, microbial mats, cyanobacteria, Laguna Amarga, Chile.Neste estudo são analisadas as cianobactérias e os sedimentos associados às esteiras microbianas formadas em torno da laguna Amarga, no Parque Nacional de Torres del Paine, sul do Chile, que, por sua riqueza em vida e características geológicas, constitui ambiente propício à observação da gênese e da disposição destas estruturas. Declarado Reserva Mundial da Biosfera pela Unesco em 1978, além da natureza exuberante, com florestas nativas, lagos e fjords, o parque expõe litologias de idade Juro-Cretáceo e intrusões de granitóides miocênicos, associados a evidências da ação do gelo, atualmente em retração. Entre os corpos dulcícolas aí presentes, a laguna Amarga, com uma área de 3,18 km², é especialmente interessante pela formação de extensas colônias de algas e esteiras microbianas, com formas nodulares, bulbosas, estratiformes e em domo. Sua análise demonstrou que as cianobactérias esféricas foram as principais responsáveis pela formação das esteiras microbianas, cuja construção é controlada por fatores ambientais. Foram identificadas 25 espécies de cianobactérias, com predomínio dos representantes das famílias Synechococcaceae Anagnostidis e Komárek 1995 (32%) e da família Chroococcaceae Nägeli 1849 (32%). A correta interpretação das estruturas orgânicas e de suas características e dos ambientes modernos em que se desenvolvem, é condição indispensável para a compreensão do contexto e dos organismos formadores das esteiras microbianas pretéritas e, assim, aplicáveis ao estudo do registro fóssil. Palavras-chave: laguna hipersalina; esteiras microbianas; cianobactérias, laguna Amarga, Chile

Análise de esteiras microbianas e cianobactérias da laguna Amarga, Parque Nacional de Torres del Paine, Chile

This study is based on cyanobacterial and sedimentary investigations of the microbial mats formed at Laguna Amarga, located at the southernmost part of South America, specifically in the Chilean Torres del Paine National Park. The Torres del Paine’s natural and geological richness is composed by large extensions of native forests, lakes, fjords and millenary glaciers presided by Paine range and Patagonian Andes. It was created in 1959 and declared Biosphere World Reserve by UNESCO in 1978. In the area, it is common to observe Late Jurassic, Cretaceous and Miocene outcrops with glacial lineations evidencing the ice retreat. The Laguna Amarga is a shallow lake with a basin area of 3,18 km2 and the habitat for extensive colonies of algae and microbial mats. On the eastern shore stromatolites with nodular, bulbous, stratiform and domal forms are found. Analyses of the microbial mats allowed the identification of 25 species of cyanobacteria. The families Synechococcaceae Anagnostidis & Komárek 1995 (32%) and Chroococcaceae Nägeli 1849 (32%) were de most frequent in the material. The microbial mats of this lake may be produced mainly by the spherical cyanobacteria. The formation of microbial mats is controlled by the high frequency of cyanobacteria and by environmental factors. The correct interpretation of the microbial mats and their features and also the environmental conditions where they are formed are important to understand analogous structures in the past and could be applied in the interpretation of ancient microbial mats. Key words: hypersaline lagoon, microbial mats, cyanobacteria, Laguna Amarga, Chile.Neste estudo são analisadas as cianobactérias e os sedimentos associados às esteiras microbianas formadas em torno da laguna Amarga, no Parque Nacional de Torres del Paine, sul do Chile, que, por sua riqueza em vida e características geológicas, constitui ambiente propício à observação da gênese e da disposição destas estruturas. Declarado Reserva Mundial da Biosfera pela Unesco em 1978, além da natureza exuberante, com florestas nativas, lagos e fjords, o parque expõe litologias de idade Juro-Cretáceo e intrusões de granitóides miocênicos, associados a evidências da ação do gelo, atualmente em retração. Entre os corpos dulcícolas aí presentes, a laguna Amarga, com uma área de 3,18 km², é especialmente interessante pela formação de extensas colônias de algas e esteiras microbianas, com formas nodulares, bulbosas, estratiformes e em domo. Sua análise demonstrou que as cianobactérias esféricas foram as principais responsáveis pela formação das esteiras microbianas, cuja construção é controlada por fatores ambientais. Foram identificadas 25 espécies de cianobactérias, com predomínio dos representantes das famílias Synechococcaceae Anagnostidis e Komárek 1995 (32%) e da família Chroococcaceae Nägeli 1849 (32%). A correta interpretação das estruturas orgânicas e de suas características e dos ambientes modernos em que se desenvolvem, é condição indispensável para a compreensão do contexto e dos organismos formadores das esteiras microbianas pretéritas e, assim, aplicáveis ao estudo do registro fóssil. Palavras-chave: laguna hipersalina; esteiras microbianas; cianobactérias, laguna Amarga, Chile

Abordagem passiva para reconhecimento de adulterações em imagens digitais através da análise do padrão CFA e do BAG

A criação e a comercialização de softwares de edição de imagens permitiu que pessoas comuns pudessem realizar qualquer tipo de manipulação em imagens digitais. Em um cenário judicial, em que autenticidade e integridade dos dados são cruciais, se faz necessário técnicas que permitam garantir tais atributos. A análise forense em imagens digitais busca, através de métodos computacionais científicos, reconhecer a presença ou ausência desses atributos. O presente trabalho apresenta um método de reconhecimento de adulteração em imagens com e sem compressão JPEG. Esse método baseia-se em técnicas de análise de inconsistência do BAG (Block Artifact Grid) e do Padrão CFA (Color Filter Array) da imagem que é gerada a partir de técnicas de adulteração, tais como composição e clonagem. Os testes foram realizados em 960 imagens, utilizando as taxas de acurácia, sensibilidade, especificidade e precisão como métricas para a avaliação da efetividade do método

Propostas para revisão dos critérios clínicos de morte encefálica

Atualmente, quase 70 mil pessoas aguardam doação de órgãos no Brasil. O Hospital das Clínicas da Universidade de São Paulo – HCFMUSP é referência em transplantes de órgãos e tecidos e, ao mesmo tempo que se realizam cirurgias de alta complexidade, capacita os profissionais de saúde, sendo um facilitador para a integração dos mesmos. A morte encefálica hoje deve ser considerada uma emergência médica, pois pode salvar várias vidas. O seu diagnóstico é realizado de acordo com a Resolução do Conselho Federal de Medicina nº 1.480/97 e, baseado nessa resolução e em nossa experiência com todo o processo de captação até o transplante, apresentamos neste artigo propostas para evitar a perda de potenciais doadores.Almost 70 thousand people await donation of organs in Brazil. The Hospital das Clínicas of the University of São Paulo is reference center in transplants of organs and woven and, at the same time that you/they take place surgeries of high complexity, it qualifies the professionals of health, being a facilitator for the integration of the same ones. Brain death today should be considered a medical emergency, because its diagnosis can save several lives. Its diagnosis is accomplished in agreement with the Brazilian Medicine Federal Council number 1.480/97 and, based on that resolution and in our experience with whole transplant process, we presented in this paper proposed to avoid the potentials donors’ loss

Evaluation of Ventral Laparoscopic Abomasopexy Using Surgical Staples Associated with Suture Material in Dairy Cattle

Background: Displaced Abomasum is known for being on of the main illnesses that affect milking cows. Increase in diagnosis of this illness is due to advancement in diagnosis techniques. Increase in incidence of this illness can be explained by genetic selection of animals with high production, breed systems and changes to the diet with a higher level of protein. For laparoscopic treatment, several surgical changes were performed to optimize the procedure and thus achieve better results. The main purpose of this study was to evaluate applicability of the ventral laparoscopic abomasopexy technique, using surgical clamps attached to the suture thread, to milking cows.Materials, Methods & Results: Six adult cows were placed under anesthesia with isoflurane and placed in dorsal decubitus. Animals were kept with no water for 24 h and no food for 48 h. Four laparoscopic accesses were performed. The first one was created with the intention of inspecting the abdominal cavity and the remaining three for access of surgical instruments. Serous membrane of the abomasum was cauterized, combined with suture threads and placed at the greater abomasal curvature. The free part of suture threads was kept out of the abdominal cavity and after traction of the abomasum against the abdominal wall was tied to the skin. Ultrasound exam was performed for abdominal evaluation after abomasopexy. Anesthesia time and surgery time were recorded and analyzes through average and standard deviation (SD). The average anesthesia time recorded was 94 min (SD 14.63 min) and average surgery time was 51 min (SD 14.71 min). The fasting period was considered adequate, however all animals had to undergo intubation with orogastric tube to drain liquids and gas during the procedure. Four of the six animals had lineal adhesion. Three of the four animals that had adhesion did not keep the abomasum at the retroperitoneal area, however viscera movement was stopped in the abdominal cavity.Discussion: Abomasopexy through laparoscopy is a safe technique, especially when compared with other invasive methods of abomasopexy. However, to perform this type of surgery availability of adequate equipment and a well trained surgical team are required. This study was performed at a surgery room under full anesthesia. In a field situation, the veterinarian can have some difficulties but such adversities must not be considered and impediment for performance of surgery on the field as its performance is possible. Even though surgical clamps were small, they were considered adequate for what was suggested. The applied 0 degree laparoscopic optic presented restrictions for cavity inspection, therefore we believe that an optical lenses with 30 degree angle could facilitate this laparoscopy inspection. To induce greater and more lasting adherence we suggest cauterizing a greater area of the serous membrane of the abomasum. We also suggest not performing this procedure during lactation peak, when fasting and surgery can cause economic losses. Complications associated with this technique could not be avoided. The technique has shown favorable results, but its clinical applicability depends on application on animals subjected to the conditions of a milk production cycle