Óleo de canola como uma alternativa para a têmpera do aço AISI 8640

AISI 8640 is one of the most used steel in the manufacturing industry due its wide range of applicability and properties. The quenching process is commonly applied in parts made of this steel in order to enhance some properties, such as strength and hardness. Petroleum derived oils are the most common quenchants, however this kind of quenchant is considered to be non-biodegradable, toxic to the health and environment, as well as, not renewable. In the present study, canola oil presented the same efficiency than a conventional petroleum derived oil in the quenching process of AISI 8640 steel billets with diameter of 25.4mm.O AISI 8640 é um dos aços mais utilizados na indústria de manufatura devido às suas grandes faixas de aplicabilidade e propriedades. O processo de têmpera é comumente aplicado em peças feitas desse aço com o objetivo de melhorar suas propriedades, como a resistência e a dureza. Óleos derivados de petróleo são os mais comumente utilizados como meio de têmpera, porém esse tipo de óleos é considerado como não biodegradável, tóxico para a saúde e o ambiente, bem como, não renováveis. No presente estudo, o óleo de canola apresentou a mesma eficiência que o óleo convencional derivado de petróleo em um processo de têmpera de tarugos de aço AISI 8640 com diâmetro de 25,4 mm

Feminine Identities

The first four essays in this volume all focus on issues of gender in the works of different English authors and thinkers. Shorter versions of each of these essays were formerly presented as papers in an autonomous section of the Research and Educational Programme on Studies of Identity at the XXth Meeting of the Portuguese Association of Anglo-American Studies (Póvoa de Varzim, 1999) and published in the proceedings of the conference. The second cluster of essays in this volume — two of which (Jennie Wang’s and Teresa Cid’s) were first presented, in shorter versions, at the joint ASA/CAAS Conference (Montréal, 1999) — addresses the work of American women variously engaged in contexts of cultural diversity and grappling with the ideas of what it means to be an American and a woman, particularly in the twentieth century. These essays approach, from different angles, the definitional quandaries and semantic difficulties encountered when speaking about the self and the United States and provide, in one way or another, a sort of feminine rewriting of American myths and history.Fundação para a Ciência e a Tecnologi

Corrosion Resistance of Ti-6Al-4V Machined Surfaces Improved by Thermal Oxidation

Ti-6A-l4V alloy is widely used in implants and prosthesis applications. Although machining is a fast and economical process, the roughness generated can compromise corrosion resistance. Thus, the goal of this study was to overcome this limitation using thermal oxidation in machined surfaces. Samples with polished surfaces were used for comparison purposes. Two sets of machining parameters were used to generate different roughness, property evaluated in polished and machined samples before and after thermal oxidation. Vickers microhardness and polarization tests using simulated body fluid (SBF) were also performed. Thermal oxidation generated similar microhardness for polished and machined samples, higher than for polished and non-oxidized condition. On the other hand, oxidation increased the roughness only for polished condition. The corrosion resistance was improved in all oxidized samples, and the best result was found to the intermediate roughness (Ra = 0.76 um), in a machined sample. The results demonstrated that thermal oxidation can be used to overcome machining limitations regarding corrosion resistance, achieving behavior even better than polished samples

New Findings Regarding the Thermal Oxidation and Biomimetic Depositions on the Corrosion Resistance of the Ti-6Al-4V Alloy

Our research group has been working on the surface functionalization of Ti-6Al-4V alloy by using thermal oxidation followed by CaP and Bi-CaP biomimetic depositions. In this short communication, we present new insights into the corrosion behaviour of the treated system by using potentiodynamic polarization tests. Our results demonstrated lower values of electric current density for the CaP specimens when compared to the Bi-CaP, indicating a tendency for the CaP samples to remake the passive film. Another reasonable explanation may be related to the displacement of CaP particles or the formation of corrosion products that partially block the pores of the coating. Morphological analyzes of all treated surfaces after the potentiodynamic polarization tests also suggest the improvement of the corrosion resistance of the Ti-6Al-4V alloy

Projeto estrutural de uma moedora de vidro destinada à Associação de Catadores de material Reciclável de São João del-Rei

Recycling has an important role on the reduction of environmental impacts caused by production via raw materials. Due to its importance to the recycling process, this study aimed to help the Recyclable Material Collectors’ Association of the city of São João del-Rei, Minas Gerais, proposing a glass grinder design. The viability of the machine was evaluated, and the components were sized. After these steps, a structural design was made, using concepts related to Materials Selection, Mechanics of Materials, Mechanical Design, Machine Design, Manufacturing Processes and Vibrations. Simultaneously, the process of building the structure was conducted, concerning the search for resources, adapting the theoretical design when needed, and also the documentation and training of the future users. Finally, the project showed satisfactory characteristics considering the primary objectives, and a high reproducibility. It has the potential to present positive social effects and reduce the environmental impact of glass waste. The process by which it was conducted was very simple and efficient, especially regarding the use of basic concepts and simple mathematical relations instead of complex analyses, favoring its application in other low-resource projects aiming mainly for a high safety factor.A reciclagem possui papel importante na redução de impactos ambientais causados pela fabricação de produtos a partir de matérias primas. Considerando seu importante papel no ciclo de reciclagem, buscou-se auxiliar a Associação de Catadores de Material Reciclável de São João del-Rei, Minas Gerais, com o projeto de uma moedora de vidro. A viabilidade do projeto foi avaliada, e alguns elementos foram dimensionados. A seguir, o projeto estrutural foi feito, com o uso de conceitos relacionados à seleção de materiais, mecânica dos materiais, projeto mecânico e de máquinas, processos de fabricação e vibrações. Simultaneamente, o processo de construção da estrutura foi conduzido, envolvendo a busca por recursos, a adaptação do design teórico quando necessário e a documentação e treinamento de futuros usuários. Ao fim, o projeto se mostrou satisfatório no referente ao funcionamento e reprodutibilidade. Por fim, ele possui potencial para causar efeitos positivos no âmbito social e ambiental, ao reduzir o impacto de resíduos de vidro deixados no ambiente. Além disso, o processo desenvolvido foi simples e eficiente, principalmente por seu uso de conceitos básicos e relações matemáticas simples, favorecendo sua possível aplicação em outros projetos com pouco recursos buscando alto fator de confiança

Effect of Arrabidaea Chica Verlot Hydroalcoholic Extract on Monosodium Iodoacetate-Induced Osteoarthritis of Rat Knees / Efeito do Extrato Hidroalcoólico de Arrabidaea chica Verlot na osteoartrite induzida por Monoiodoacetato de Sódio em joelhos de ratos

Introdution: The Arrabidaea chica Verlot (A. chica, ACV), with well-demonstrated anti-inflammatory properties,  appears as an option with therapeutic potential for the osteoarthritis; thus, validating its use is highly relevant. Method: 72 rats were allocated to 3 groups: control, osteoarthritis and phytotherapy {these last two were subjected to osteoarthritis induction, and treated orally with 0.9% normal saline (0.1 mL/100 g) and ACV hydroalcoholic extract (500 mg/kg), respectively, from days 7 to 28}. The 3 groups were subjected to weekly (days 7, 14, 21, 28) assessments including clinical tests (weight-bearing and von Frey), radiological and histopathological analyses.  Fractionation of the ACV´s hydroalcoholic extract was performed and it´s fractions were analysed. Results: The evaluation of the values of the osteoarthritis and phytotherapy groups showed significant difference, with p <0,05 : weight-bearing- on days 14 (29,64 x 35,52), 21 (32,62 x 42,53) and 28 (33,56 x 47,14), von Frey- on days 14 (31,12 x 37,80), 21 (30,24 x 41,48) and 28 (35,78 x 46,09),  x-ray- on days 21 (2,17 x 1,20) and 28 (2,33 x 1,40), and histopathological analysis- on day 28 (0,03 x 2,20). The fractionation of the extract obtained the FH (hexane), FC (chloroform), FAE (ethyl acetate) and FB (butanolic) fractions. The FAE had highest total polypnenolic contents and the FH had the highest concentration of total flavonoids. Conclusion: The ACV extract promoted a reduction in static incapacitance, allodynia, radiological score and degree of synovitis, and FAE and FH fractions are probably the fractions responsible for the anti-inflammatory and analgesic activities of the ACV extract

A Palavra e a Imagem

Num quadro teórico-crítico, influenciado por teorias contemporâneas de classe, género e etnia, vamos considerar os confrontos entre culturas, materializados em diversas práticas discursivas e visuais, que estudaremos transdisciplinarmente, numa perspectiva formal e como documentos. São exemplos das referidas práticas, por um lado, a escrita jornalística, que as novas tecnologias estão a desenvolver exponencialmente, a ensaística, o conto, o relato de viagem e biográfico, o romance, o poema, o drama e, por outro lado, as múltiplas imagens em suporte digital, o design, a fotografia, o vídeo, o cinema, a arquitectura, a gravura. Os ensaios publicados avaliam os estudos da palavra, ou da imagem visual, ou das formas diferentes como elas interagem, em relação a temas cronologicamente localizados entre o século XVIII e o século XXI.Fundação para a Ciência e a Tecnologi

USO DE MEMBRANA AMNIÓTICA HUMANA DESCELULARIZADA EM ANASTOMOSES INTESTINAIS: ESTUDO EM RATOS TRATADOS COM 5-FLUOROURACIL

Introduction: currently, the most relevant applications of perinatal derivatives are in wound healing, for example, the use of amniotic membrane (AM) as a biomaterials source for use in different healing processes. The anastomotic healing compromised by antimetabolic drugs, such as 5-fluorouracil (5-FU), is a potential target of AM. Objective: To evaluate the healing effects of the AM use in rats treated with 5-FU at a dose of 20 mg/kg on the 7th postoperative day, regarding the parameters percentage of type I collagen (mature), cell viability, microvascular density and granulation tissue formation. Method: Thirty-two Wistar rats were submitted to colotomy and colorraphy, separated in 4 groups with 8t rats each and received, by 7 days, different treatments intraperitoneally, once daily from the operation day until sacrifice: 1- saline solution (C), 2- 20 mg/kg 5-FU, 3- 20 mg/kg 5-FU and 4- MA, and MA. Results: Tthe treatment with 5-FU (20 mg/kg – 7 days) induced adverse effects in the anastomotic healing process evidenced by the decrease of type I collagen (mature), cell viability, percentage microvascular density, granulation tissue formation (leukocyte-fibrin crust and angio-fibroblastic proliferation). The use of AM, under these conditions, induced an improvement in type I collagen (mature) percentage. Conclusion: The treatment with 5-FU induced adverse effects on the healing anastomotic process, and the use of AM, under these conditions, induced improvement in type I (mature) collagen percentage.Introdução: Atualmente emerge em nosso meio aplicações mais relevantes dos derivados perinatais, por exemplo, a membrana amniótica (MA), como fonte de biomateriais para emprego em diferentes processos cicatriciais. O comprometimento anastomótico por drogas antimetabólicas como o 5-fluorouracil (5-FU) é um potencial alvo da MA. Objetivo: Avaliar os efeitos cicatriciais do uso da MA em ratos tratados com 5-FU na dose de 20 mg/kg ao 7º. dia de evolução pós-operatória quanto aos parâmetros porcentagem de colágeno tipo I (maduro), viabilidade celular, densidade microvascular e formação do tecido de granulação. Método: Utilizaram-se 32 ratos da linhagem Wistar submetidos à colotomia e colorrafia separados em 4 grupos com 8 e receberam diferentes tratamentos diariamente por via intraperitoneal até o dia do sacrifício: Solução fisiológica (C), 20  mg/kg 5-FU, 20 mg/kg 5-FU e MA, MA. Resultados: O tratamento com 20 mg/kg de 5-FU, ao 7º. dia pós-operatório induziu efeitos adversos no processo cicatricial anastomótico evidenciados pela diminuição da porcentagem de colágeno tipo I (maduro), da viabilidade celular, da densidade microvascular, da formação de crosta fibrinoleucocitária e da proliferação angiofibroblástica; o uso da MA nestas condições induziu melhora da porcentagem de colágeno tipo I (maduro). Conclusão: O tratamento com 20 mg/kg de 5-FU, ao 7º. dia pós-operatório induziu efeitos adversos no processo cicatricial anastomótico e o uso da MA nestas condições induziu melhora da porcentagem de colágeno tipo I (maduro)