Influência do retardante de chamas nas propriedades mecânicas e flamabilidade em compósitos poliméricos de epóxi/fibra de curauá

Currently, there is a great search for materials derived from renewable sources. The vegetable fibers as reinforcement for polymer matrixes, has been used as an alternative to replace synthetic fibres, being biodegradable and of low cost. The present work aims to develop a composite material with epoxy resin reinforced with curauá fibre with the addition of alumina trihydrate (aluminum hydroxide, Al(OH)3) as a flame retardant, which was used in proportions of 10 %, 20% and 30% of the total volume of the composite. The curauá fibers have gone through a cleaning process with an alkaline bath of sodium hydroxide (NaOH ), parallelized by hand and cut carding according to the default length . They were molded composites with fibers 30cm. Composites were molded in a Lossy Mold with unidirectional fibres in the proportion of 20% of the total volume of the composite. The composites were prepared in the Chemical Processing Laboratory of the Textile Engineering Department at UFRN. To measure the performance of the material, tests for the resistance to traction and flexion were carried out. with samples that were later analyzed in the Electronic Microscopy Apparatus (SEM ). The composites showed good mechanical properties by the addition of flame retardant and in some cases, leaving the composite more vulnerable to breakage. These mechanical results were analyzed by chi-square statistical test at the 5% significance level to check for possible differences between the composite groups. Flammability testing was conducted based on the standard Underwriters Laboratory 94 and the material showed a satisfactory result taking their average burn rate (mm / min) decreasing with increasing addition of the flame retardant composite.

Condições de trabalho e saúde psíquica de servidores técnico-administrativos da UFRN

Unfavorable working conditions constitute one of the factors that may contribute to cause psychic suffering and behavioral disorders in workers. This research aimed to characterize the working conditions public servant technical- administrative , specifically the auxiliaries and assistants in administration of the Federal University of Rio Grande do Norte – UFRN, Natal, Brasil, as well to identify the incidence of psychic suffering in this group of public servants. As a strategy, we chose a case study of multi-method type, descriptive with quantitative and qualitative sequential steps. For this, it initially performed desk research by surveying epidemiological data for these public servants working in central campus, to identify the major diseases presented in the period from January 2011 to June 2014. Then, we proceeded to diagnostic step of the aspects related to work, by applying online and in loco of Working Conditions Survey (already validated by Borges et al., 2013a) in 11 sectors selected according to the following criteria: high number of workers public servants and major and minor percentage of absences for health care for ICD-F (according to records of Sector of Workers Health Care - DAS). In the treatment of the data the spreadsheet editor software Microsoft Office Excel and statistical SPSS Statistical Package for Social Sciences were used and made qualifying type of content analysis of open questions. Applied to this study 174 public servants and the results show a predominance of absenteeism due to mental or behavioral disorders (ICD F), musculoskeletal diseases (ICD M) and respiratory system (ICD J). Among the factors that were significant are the working hours (contractual and legal); Physical Effort (M = 2.59) and workspace (M = 2.58) - physical and material conditions; encouraging collaboration (M = 3.5) - processes and characteristics of the work; and participation (M = 1.78) - social-management environment. Therefore, it infers the existence of a relationship between these factors and some of the reasons for absenteeism reported by participants. It is suggested the expansion of this research with studies involving other professionals (including scholarship workers and contractors) and specific sectors.

Síntese de ferritas de cobalto e níquel dopadas com zinco e caracterização de suas propriedades eletromagnéticas

This work shows that the synthesis by combustion is a prominent alternative to obtain ceramic powders of higher oxides, nanostructured and of high purity, as the ferrites of formulas Co(1-x)Zn(x)Fe2O4 e Ni(1-x)Zn(x)Fe2O4 with x ranging from 0.2 mols, in a range from 0.2 ≤ x ≥ 1.0 mol, that presents magnetic properties in coexistence of ferroelectric and ferrimagnetic states, which can be used in antennas of micro tapes and selective surfaces of low frequency in a range of miniaturized microwaves, without performance loss. The obtainment occurred through the combustion process, followed by appropriate physical processes and ordered to the utilization of the substrate sinterization process, it gave us a ceramic material, of high purity degree in a nanometric scale. The Vibrating Sample Magnetometer (VSM) analysis showed that those ferritic materials presents parameters, as materials hysteresis, that have own behavior of magnetic materials of good quality, in which the magnetization states can be suddenly changed with a relatively small variation of the field intensity, having large applications on the electronics field. The X-ray Diffraction (XRD) analysis of the ceramic powders synthesized at 900 °C, characterize its structural and geometrical properties, the crystallite size and the interplanar spacing. Other analysis were developed, as Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), electric permittivity and the tangent loss, in high frequencies, through the equipment ZVB - 14 Vector Network Analyzer 10 MHz-14 GHz, of ROHDE & SCHWART.

Avaliação da fertilização azotada na produtividade e qualidade da variedade Hermes para indústria

O azoto é determinante na produtividade e na qualidade da batata para indústria. Com este trabalho pretendeu-se avaliar o efeito de diferentes doses de azoto na variedade de batata “Hermes”, em plena condições de cultivo do Vale do Tejo. Os tratamentos consistiram na aplicação de 0 (N0), 80 (N80), 160 (N160), 240 (N240) e 320 (N320) kg de azoto/ha, na forma de ENTECÒ 26. O ensaio foi instalado em parcelas totalmente aleatórias, com 4 repetições. Foi registado semanal a taxa de cobertura de solo pelo método da grelha até à sua cobertura total. Bissemanalmente, foram recolhidas plantas nos tratamentos N0 (0kgN/ha) e N160 (160kgN/ha) para avaliação do seu desenvolvimento e crescimento. No final do ciclo cultural avaliou-se a produção total, comercial, em peso e número de tubérculos. Avaliou-se ainda o peso específico, os teores em matéria seca dos tubérculos e a percentagem do azoto total na matéria seca das folhas e tubérculos. A adubação azotada influenciou a dimensão do aparelho fotossintético, através do estímulo de ramificações. Verificou-se uma maior produtividade de tubérculos nos tratamentos com maior aplicação de azoto, embora os acréscimos tenham sido menores a partir dos 160kg/ha. O azoto influenciou a percentagem de tubérculos de maior calibre.

As políticas educacionais em Minas Gerais e seu impacto no plano de carreira dos trabalhadores em educação (2003-2014)

Based on the theoretical approach on the structure and functioning of the capitalist mode of production in the light of the Marxian perspective of Althusser, Poulanzas and Saes, the objective of this study is to describe and analyze the career path of the deployment process of education workers public state of Minas Gerais, in the context of neoliberal educational policies implemented in the period 2003-2014. This study will make use of the techniques of bibliographical and documentary research; to do so, we will try, at first, to establish the correspondence of this peculiar mode of production (capitalism) and the bourgeois state, trying to understand their legal and political structure, characterized by the right and the bourgeois bureaucracy, highlighting the importance of the state apparatus to conditioning ideologies and their structures for prescription of social practices. In the second phase, we will present to the prevailing ideologies School appear in the form of speech and legal and governmental practices in today's society. Finally, we will seek to understand the applicability of the theory studied in the concrete reality of educational public policies implemented in Minas Gerais, in the perspective of democratic government, modernized and efficient state, as opposed to the interests of the Single Union of Education Workers (Sind-UTE / MG). Thus, we can conclude that our work object is to analyze the educational policies of the bourgeois state, focusing on career path in the context of Minas Gerais, from 2003 to 2014, and its social, political and economic education for workers Minas Gerais state and the society today.