bluuebunny/crossref_metadata_2025 huggingface dataset:
Matemática no Ensino Médio com um enfoque crítico: contribuições à formação de cidadãos
Authors: Oechsler Vanessa , Gaertner Rosinéte
Published: August 2016

Os documentos que norteiam o Ensino Médio no Brasil, como a Lei de Diretrizes e Bases da Educação (LDB), os Parâmetros Curriculares Nacionais do Ensino Médio e as Orientações Curriculares para o Ensino Médio preconizam uma educação em que o estudante seja preparado para exercer seu papel de cidadão. Tendo em vista essa orientação, este artigo apresenta duas atividades, produto de uma dissertação de Mestrado Profissional, que abordam a Matemática, de forma a contribuir para o exercício da cidadania dos jovens. Essas propostas foram criadas a partir de uma pesquisa bibliográfica, em que foram estudados os documentos que norteiam o Ensino Médio, bem como a definição de cidadania e o movimento da Educação Matemática Crítica, que alia a ideia de cidadania com o ensino de Matemática.
M-learning e suas Múltiplas Facetas no contexto educacional: Uma Revisão da Literatura
Authors: Cleophas Maria Das Graças , Cavalcanti Eduardo Luiz Dias , Souza Francislê Neri de , Leão Marcelo Brito Carneiro
Published: August 2016

Este artigo apresenta uma investigação sobre o uso dos dispositivos móveis (m-learning) no cenário brasileiro. Para tanto, inicia-se com uma discussão sobre o uso do m-learning no contexto educacional, suscitando algumas questões relevantes sobre essa temática, tais como a sua definição, vantagens e desvantagem sobre a sua integração diante do processo de ensino e aprendizagem das Ciências Naturais. Este trabalho trata-se de uma revisão sistemática da literatura, cuja análise possui teor qualitativo. Foram utilizados como fonte de pesquisa os periódicos da área de educação. Ao todo, analisaram-se 32 periódicos, sendo encontrados 36 artigos. Estes artigos foram classificados em seis dimensões que emergiram através da análise realizada. Os resultados deste trabalho apontam para uma preocupação mais latente sobre a produção de plataformas de desenvolvimento em apoio às tecnologias móveis e/ou ferramentas, do que para a compreensão fenomenológica sobre o uso dos dispositivos móveis em sala de aula.
Planejando aulas de botânica a partir de uma provocação
Authors: Carmo-Oliveira Renata , Carvalho Daniela Franco
Published: August 2016

Esse texto aborda o desenvolvimento de uma ação na disciplina de Estágio Supervisionado em Biologia na tentativa de compreender o que poderia estimular futuros professores a planejarem aulas interativas na temática da Botânica para o Ensino Médio, tendo como base um roteiro confeccionado a partir do modelo de design pedagógico e dos recursos didáticos botânicos que estavam dispostos em quatro estações sobre as bancadas do Laboratório de Ensino de Ciências e Biologia. A coleta de dados ocorreu por meio da metodologia da observação discreta. As estações provocaram comportamentos e interesses distintos nos licenciandos, levando-os a se dirigirem primeiramente às estações com o material vivo ou fresco. Foi possível observar dificuldades em todos os grupos, independentemente do tipo do material, para a elaboração dos planejamentos de aula. A partir dos dados discutimos a proposta de provocação relacionada à criatividade e autonomia do professor.
Dificuldades enfrentadas por Professores de Ciências para ensinar Física no Ensino Fundamental
Authors: Melo Marcos Gervânio de Azevedo , Campos Joanise Silva , Almeida Wanderlan Dos Santos
Published: August 2016

O objetivo deste estudo é verificar que obstáculos estão presentes no ensino de Física realizado por professores de ciências das escolas municipais que trabalham com alunos do ultimo ano do ensino fundamental na cidade de Alenquer localizada no oeste do Pará. Foi realizada uma entrevista com os professores de Ciências que trabalham com as turmas do 9º ano nas escolas do município. Observou-se que dos cinco professores entrevistados trabalhando em escolas do município de Alenquer e que lecionam Física no último ano do ensino fundamental, nenhum possui formação em Física. Verificou-se também que os professores trabalham priorizando conteúdos de mecânica. Percebeu-se que um ponto que certamente contribui para uma repulsa à disciplina de Física, por parte dos alunos, é a cultura intensificada quase sempre por professores que acreditam piamente que as aulas práticas devam ocorrer em laboratórios sofisticados e que a falta dos mesmos inviabiliza os procedimentos práticos na escola.
Developing a Program Evaluation Plan: Options and Opportunities
Authors: Lubejko Barbara G.
Published: August 2016

Planning how to evaluate educational programs needs to be a thoughtful process that begins early in program planning. By considering a series of questions and choosing between direct and indirect outcome measures, the evaluation process can provide useful data about successes and opportunities.

J Contin Educ Nurs
. 2016;47(9):388–389.
Integrating Systems Thinking Into Nursing Education
Authors: Phillips Janet M. , Stalter Ann M.
Published: August 2016

A critical need exists for nursing leadership in current complex health care settings. Systems thinking can be incorporated into nursing education at all levels by using evidence-based principles in education. Teaching tips are provided using a systems awareness model to guide nurse educators in the assessment and integration of systems thinking and engaging learners in interprofessional education and practice.

J Contin Educ Nurs
. 2016;47(9):395–397.
Knowledge and Competency of Nursing Faculty Regarding Evidence-Based Practice
Authors: Orta Roxana , Messmer Patricia R. , Valdes Guillermo R. , Turkel Marian , Fields Sheldon D. , Wei Christina Cardenas
Published: August 2016

The Institute of Medicine recommended that 90% of clinical decisions should be evidenced based by 2020. Both the IOM and the American Association of Critical-Care Nurses identified evidenced-based practice (EBP) as a core competency for practice. EBP can reduce costs, improve patient outcomes, and ensure optimal nursing interventions. Because nursing faculty may have deficits in knowledge, attitudes, and competencies to teach EBP, few nursing students conduct EBP reviews. The purpose of this project was to develop EBP educational resources to increase nursing faculty knowledge and competency of EBP in a southeastern college with both a multicultural faculty and student body. A pre- and postsurvey design using Stevens' ACE Star Model of Knowledge Transformation and Evidence Based Practice Readiness Inventory (ACE-ERI) determined the effectiveness of the educational intervention. Results indicated that faculty's self-confidence about their competency in EBP increased significantly from presurvey to postsurvey,
t
(17) = −2.04,
p
= .028, but there was no significant change from pretest to posttest,
t
(17) = −0.576,
p
=.572, for the EBP knowledge component of ACE-ERI. The results of the study suggest that educational programs for RN-to-BSN faculty are vital in increasing participant's readiness for EBP.

J Contin Educ Nurs.
2016;47(9):409–419.
Empowering Patients, Engaging Teams: An Interprofessional Continuing Education Pilot
Authors: Moyer Aislynn R.
Published: August 2016

Health care is moving from reactive, disease-focused systems to proactive, patient-centered systems focused on the health continuum. This shift requires ongoing education on the part of the health care team to ensure care competence and the ability to meet patients where their needs exist. To maximize outcomes, interprofessional continuing education is necessary to support interprofessional collaboration. One health system embraced this by piloting an interprofessional, continuing education population health course. The course encouraged team members to learn from, with, and about each other while gaining skills in patient engagement. Outcomes showed an increased knowledge and confidence in the ability to support patients, as well as a greater desire to work together as a team toward population health.

J Contin Educ Nurs.
2016;47(9):421–426.
Sintering of Manganese Ore Tailings under an Argon Atmosphere
Authors: Lima Margarida Márcia Fernandes , Valduga Fillipe , Lima Rosa Malena Fernandes
Published: August 2016

Manganese is a chemical element widely used in Metallurgy. In Brazil, the ore’s beneficiation processes discharge the tailings (fraction size 0.106mm) with considerable Mn content. It would be interesting to recover this material. The aim of this work was to obtain and characterize the sinters from the manganese ore tailings at the Morro da Mina Mine. The fines (37 μm) were calcinated at 800°C for 3600s, and afterwards, homogenized with activated charcoal (7 and 10%) and CaO (5 and 10%). The sintering were carried out at 1135, 1140 and 1145°C during 7200 and 14400s under an argon atmosphere. The sintered products were characterized by BET surface area, apparent density, X-ray diffraction, MO and SEM/EDS. The presence of potassium from the alkalis justified the low melting point of the tailings (1145°C). Due to the chemical complexity of the tailings, several phases were identified in the products: pores, silicates with a high content of manganese in the matrix, as well as other silicates with different proportions of Al, Mn, Mg and Ca, pure Fe, and SiO2, etc.
Factorial Design for 32 Experimental Planning of Clay Ceramic Incorporated with Ornamental Stone Waste
Authors: Bozzi Piazzarollo Carla , de Castro Xavier Gustavo , Alexandre Jonas , de Azevedo Afonso Rangel Garcez , Vieira Carlos Maurício Fontes , Monteiro Sergio Neves , de Oliveira Braga Fabio
Published: August 2016

In recent decade there has been a worldwide trend towards encouraging the recycling of solid wastes. Both environmental and economical issues motivate recycling of industrial wastes from practically all productive sectors. In particular, the ornamental stone industry generates a significant amount of wastes in the form of small rocks and sludge. Several works have investigated the possibility of incorporation of these ornamental stone wastes (OSW) into red clay ceramics. Promising results were reported but the optimum condition the terms of composition and firing temperature are still to be defined. Therefore, the present work investigated the best values for the main technical properties through an experimental planning using 32 factorial design associated with the incorporation of OSW into clay ceramics. The best combination of strength and water absorption was found for 12 wt% incorporation and firing temperature of 920°C.
Influence of Reburning on the Pozolanicity of Sugar-Cane Bagasse Ashes with Different Characteristics
Authors: Ferreira Ramon Tadeu Lopes , Nunes F.M.M.P , Bezerra Augusto Cesar da Silva , Figueiredo Roberto Braga , Cetlin Paulo Roberto , de Aguilar Maria Teresa Paulino
Published: August 2016

Studies about concrete production of low environmental impact often seek materials that can partially substitute Portland concrete. Accordingly, we highlight residues, which can be used as pozzolanic and cementitious materials and/or as fillers. Abundant in Brazil, ash is a residue derived from the burning of sugar-cane bagasse. The burning conditions influence its pozzolanic characteristics, which could contribute to a greater durability of the cementitious composite. Burning processes are different at each sugar cane mill, thus generating ashes with different characteristics and making their their application more restrict. This paper analyzes the reburning process with the purpose of evaluating the homogenization and development of ashes’ pozzolanic characteristics from different sources. Chemical analysis, physical characterization and tests were carried out to analyze the pozzolanicity of ashes both in natura and after reburning. The results revealed that the thermal treatment enables a better homogenization of different sugar-cane ashes.
Microstructural Characterization of Ornamental Rock Samples: Cariri Rocks
Authors: Lisbôa da Costa Danúbia , Fernandes Ingrid Mayara Medeiros , Braga Aluska Nascimento Simões , da Costa Farias Rosiane Maria , Menezes Romualdo Rodrigues , Neves Gelmires Araújo
Published: August 2016

Ornamental rocks are among the most promising business areas of the mineral sector, raising the necessity for, besides beauty, investments in quality, safety and characterization in the various application fields of these rocks. So, this work aims at the microstructural characterization of the class of these rocks: the Cariri Rocks, also known the limestone, which are calcareous rocks mainly formed by calcium and magnesium carbonate, possibly presenting variations due to their origins. For characterization, we studied four samples, being two from Chapada do Apodi and two from Chapada do Araripe, characterized physically and micro-structurally through chemical analysis, X-ray diffraction, optical micrography and porosimetry tests. The results prove that the limestones are calcitic and dolomitic, and present porosity varying from 5 to 15%, with pores concentration between 100nm and 10μm, besides the high microstructural heterogeneity.
Recycled Alumina Production from the Anodizing Industry to Tubulation Coating of Petroleum Craking
Authors: de Carvalho M.F. , de Sousa Andrea G. , Ferreira Ricardo Arthur Sanguinetti , Shinohara A.H. , Yadava Y.P.
Published: August 2016

The anodizing of aluminum is a common technique used to produce decorative and protective high quality film. This process results in significant volume of industrial sludge containing considerable amounts of colloidal aluminum hydroxide, which is a problem in the disposal of these industrial wastes due to the environmental impact. This paper aims at the treatment of theses residues, which were heat-treated at the temperatures of 200°C, 1000°C and 1400°C. After each treatment, the residues were put to the X-Ray Difraction and the X-ray Fluorescence analysis. In evaluating these results, it was found a gradual increase of the percentage of alumina at 1400°C to achieve 93%. With the acquisition of ceramic mass with a high content of alumina, the objective being to make a refractory to coat the petroleum refining pipes, thereby solving an environmental problem from the aluminum industry, presenting an alternative to the petroleum industry. These residues were compacted and immersed in land and sea petroleum for 30 days, after this period its mechanical properties were analyzed to study its response to the contact with the petroleum, where it was found that these remained kept.
The Use of Dust Emission from Foundry Industry as Raw Material to the Industry of Ceramic Coating
Authors: Cúnico F.R. , Folgueras Marilena Valadares , Schmitt T.J.B. , Carnin R.L.P. , Bruno M.A.B.
Published: August 2016

Industrial dust emission is a kind of pollution which might occur due to the green sand mold process in the foundry industry. This material is predominately composed by sand, clay, carbon and metallic oxides. The ceramic industry has already assumed the role of consumer of by-products generated by such industries, mainly by having similarity between the composition of by-products and raw material employed in the ceramic sector. In a preliminary study the dust from exhaustion was define as a thin material with a high content of non-plastic material and the presence of carbon, which can interfere with processing and properties of the final product. This study aims to show the effect of exhaustion powder addition in atomized clay in order to develop ceramic coating. The results of the effect of sintering temperature and the percentage of residue on properties such as apparent density, linear shrinkage, water absorption and open porosity are presented.
Beneficiation of Kaolins by Hydrocycloning
Authors: de Figueirêdo J.M.R. , de Oliveira P.L. , Santana L.N.L. , Menezes Romualdo Rodrigues , Neves Gelmires Araújo , Ferreira Heber Carlos
Published: August 2016

Kaolin is a white clay, formed by hydrated aluminum silicates, which has several industrial applications. Since it is associated to impurities and presents considerable contents of contaminant elements that interfere in its performance and in its applications, kaolin must pass through a beneficiation process in order to meet the market's demands. The purpose of this work is to study the use of a hydrocyclone in the beneficiation of primary kaolins from Província Pegmatítica da Borborema. The samples were characterized by cation-exchange capacity (CEC), granulometric analysis by laser diffraction (GA), chemical composition by X-ray fluorescence (EDX), X-ray diffraction (DRX), differential thermal analysis (DTA) and thermogravimetric analysis (TG). The purification process did not show good results for kaolin in ABNT 200 mesh in the attempt to obtain colloidal kaolin. On the other hand, it presented very promising results for the beneficiation of raw kaolin, proving the feasibility of the application of this technology to the granulometric classification of this mineral, being an alternative route for the processes adopted in the regional kaolin beneficiation plants, which use washing and sieving.
Comparison between Rice Husk Ash and Commercial Silica as Filler in Polymeric Composites
Authors: Fernandes Iara Janaína , Calheiro Daiane , dos Santos Emanuele Caroline Araújo , Oliveira Roxane , de Campos Rocha Tatiana Louise Avila , Moraes Carlos Alberto Mendes
Published: August 2016

The use of rice husk ash (RHA) as filler in polymeric materials has been studied in different polymers. Research reported that RHA may successfully replace silica. The silica production process using ore demands high energy input and produces considerable amounts of waste. Therefore, the replacement of silica by RHA may be economically and environmentally advantageous, reducing environmental impact and adding value to a waste material. In this context, this study characterizes and compares RHA of different sources (moving grate and fluidized bed reactor) with commercially available silicas to assess performance as filler in polymeric materials. Samples were characterized by X-ray fluorescence, loss on ignition, X-ray diffraction, grain size, specific surface area, specific weight, and scanning electron microscopy. The results show that RHA may be used as a filler in several polymeric materials.
Mechanical Analysis of Polybenzoxazine Matrix in Fiber Metal Laminates
Authors: Vilas Boas Cristiane , Moreno Felipe , dos Santos Demetrio Jackson
Published: August 2016

In this work we investigated the application of a novel high performance polymer, polybenzoxazine, as a polymeric matrix in Fiber Metal Laminates (FML). This polymer, when applied on the development of FMLs, generated higher mechanical properties in comparison to fiber metal laminates obtained with epoxy. To investigate the mechanical performance of the polybenzoxazine matrix in FMLs, a mechanical behavior comparison was carried out among epoxy matrix laminates - glass fiber reinforced aluminum laminate (GLARE) and carbon fiber reinforced aluminum laminate (CARALL) - and FML constructed with aluminum and carbon fiber reinforced polybenzoxazine. The mechanical properties were characterized by drop weight impact and flexural methods, and the polybenzoxazine curing behavior through differential scanning calorimetry (DSC). Polybenzoxazine FML generated increasing of: 18% of maximum load, 11% of maximum elongation under flexure and 7.5% of impact energy absorption compared to other fiber metal laminates.
Tensile Behavior of Epoxy Composites Reinforced with Thinner Fibers of Sugarcane Bagasse
Authors: Scarpini Cândido Verônica , Monteiro Sergio Neves
Published: August 2016

Surgarcane bagasse is an industrial waste partially used as fuel for sugar and ethanol processing boilers. A considerably amount of bagasse, however, is disposed into the environment without a practical use. Research works are investigating the possible application of the fibers of these bagasse waste as reinforcement of polymer composites. Thus, the aim of the present work was to evaluate the mechanical behavior of epoxy composites reinforced with different volume fractions, up to 30 %, of thinner sugarcane bagasse fibers. Specimens with aligned fibers were tensile tested at room temperature and the ultimate strength, elastic modulus and total deformation results indicated a superior performance as compared to composites reinforcement with average thicker bagasse fibers
Charpy Toughness Behavior of Eucalyptus Fiber Reinforced Polyester Matrix Composites
Authors: Barbosa Anderson de Paula , Muylaert Margem Frederico , Oliveira Caroline Gomes , Tonini Simonassi Noan , de Oliveira Braga Fabio , Monteiro Sergio Neves
Published: August 2016

This work investigated the toughness behavior of polyester matrix composites reinforced with up to 30% in volume of long, continuous and aligned fibers extracted from the eucalyptus wood by means of Charpy impact tests. It was found that the addition of eucalyptus fibers results in a marked increase in the absorbed impact energy of the composites. Macroscopic observation of the post-impact specimens and SEM fracture analysis showed that longitudinal rupture through the Eucalyptus fiber interface with the polyester matrix is the main mechanism for the remarkable toughness of these composites.
Composites Based on Thermoset Resin and Orbignya phalerata (Babassu Coconut): Evaluation of Mechanical Properties, Morphology and Water Sorption
Authors: Fonteles Carlos Alberto Lopes , Brito Gustavo Figueiredo , Carvalho Laura Hecker , Alves Tatianny Soares , Barbosa Renata
Published: August 2016

Researches in plant fiber composites have been developed with greater frequency during the last years, especially on environmental issues. The opening of the market, especially in the automotive sector, points to the replacement of synthetic additives by natural reinforcements. Characteristics such as low density and abrasiveness, superior mechanical properties and low cost are the most sought in these composites. The aim of this study was to evaluate the behavior of composites based polyester matrix and fiber of the babassu coconut epicarp, at levels of 5, 7.5 and 10% under testing of tensile strength and impact, as well as the morphology by microscopy scanning electron and water absorption. All composites were prepared raw fibers and fiber with treated with alkaline solution of 5% NaOH. As regards the mechanical properties, an increasing of the rigidity of the system was observed, and the kinetics of water absorption increased levels indicated for compounds with high content of fibrous reinforcement. By SEM there was greater interaction between fiber and matrix.
Carnauba and Rhea Americana Eggshell Powder Incorporation in PHB Bionanocomposites
Authors: Rocha Yago César do Nascimento , Sá Marcel Leiner , Alves Tatianny Soares , Barbosa Renata , Carvalho Laura Hecker , da Silva Neto João Emídio
Published: August 2016

In this work PHB poly (3-hydroxybutyrate) bionanocomposites with carnauba or emu eggshells (rhea americana), in amounts of 1 to 3 % wt%, were obtained by solution intercalation. Neat PHB solutions were prepared at room temperature under constant stirring for 3 hours and at rest 24 hours. The solution was then heated to 80°C and stirred for 3 hours before filler addition. Polymeric films were obtained by casting and solvent evaporation at room temperature. The filler were characterized by X-ray diffraction and thermal analysis and the films were characterized by X-ray diffraction, scanning electron and optical microscopies. System morphology was dependent on filler identity.
Characterization by Fourier Transform Infrared (FTIR) Analysis for Natural Jute Fiber
Authors: da Silva Isabela Leão Amaral , Bevitori Alice Barreto , Araújo Rohen Lazaro , Muylaert Margem Frederico , de Oliveira Braga Fabio , Monteiro Sergio Neves
Published: August 2016

The world is ever more demanding materials that are not only less intensive in terms of processing energy but also environmentally friendly. Presently, issues like generalized pollution and global warming are renewing the interest of natural materials in substitution for synthetic ones. In fact, natural lignocellulosic fibers are today the subject of a growing number of studies. In particular, the jute fiber, has been investigated by various mechanical and thermal analyses. With the intention to further characterize this fiber, a specific method was considered in this work, the infrared spectroscopy. The Fourier Transform Infrared (FTIR) was used to reveal the most typical absorption bands of specific molecular components of jute fibers, in order to understand the interaction that occurs between the jute fiber and a polymer matrix.
Nondestructive Analysis of Bi2212 Bulk Superconducting Ceramics in the C-Axis Direction
Authors: Bigansolli Antonio Renato , da Cruz T.G. , Rodrigues Jr. Durval
Published: August 2016

The use of superconductors of high critical temperatures in applied superconductivity leads to higher operation temperatures and economy of cryogenic fluids. High temperature superconductor materials exhibits limited transport properties due to grain boundary weak-links and anisotropy on the critical currents. The texturing development in these superconductors decreases in an efficient way the number of high-angle grain boundaries, increasing the values of the critical current densities. Several quantitative analysis methods have been developed to study the morphologic and topologic characteristics improving our understanding of structural parameters. In this work the grain size distribution characterization of Bi2Sr2CaCu2O8+δ Bi2212 superconductor bulk samples heat treated under the influence of an external applied magnetic field of 5T was carried out using a processing technique and analysis of images. The analyzed images were obtained by SEM in the c axis direction. All samples showed similar microstructures on both cases, but with the use of an external applied magnetic field during the heat treatments the average grain size decreased.
Effect of Molecular Weight of Polyamide 6 in Rheological Properties of Nanocomposites with Brazilian Organoclay
Authors: da Paz Renê Anísio , Leite Amanda Melissa Damião , Araújo Edcleide Maria , Melo Tomás Jeferson Alves , Pessan Luiz Antonio , Passador Fábio Roberto
Published: August 2016

Polyamide 6 (PA6)/Brazilian organoclay nanocomposites were obtained by melt intercalation and the structural and rheological properties were studied. The nanoclay was treated with quaternary ammonium salt (Cetremide) and characterized using infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results indicated the effective organophilization of nanoclay. The nanocomposites were obtained by melt intercalation using a twin screw corrotacional extruder in two steps. Firstly, a masterbatch of PA6 / nanoclay (1: 1) was prepared. In the second step the masterbatch was diluted in PA6 to obtain 3 and 5 wt% of nanoclay in the nanocomposites. The specimens were injection molded and analyzed using capillary rheometry, X-ray diffraction and transmission electron microscopy (TEM). The results of capillary rheometry showed that the presence of the organoclay in PA6 increased the viscosity of the systems. Structural characterization showed that the nanocomposites were predominant in exfoliated structure.
Evaluation of Biodegradation of PHB/PP-G-MA/Vermiculite Bionanocomposites
Authors: Mesquita Priscylla Jordânia Pereira , Araújo Rayson de Jesus , Andrade Daniela de Lourdes Anjos C. Simões , Carvalho Laura Hecker , Alves Tatianny Soares , Barbosa Renata
Published: August 2016

In this study, the biodegradation process of PHB/PP-g-MA/clay bionanocomposites was evaluated. Films with compositions of 5% PP-g-MA and 3% clay (BIO5); and 2.5% PP-g-MA and 3% clay (BIO2,5) were prepared. The biodegradation test was performed according to ASTM G 160-03 for a period of 86 days. The evaluation of the degradation was carried out by optical microscopy (OM), weight loss, FTIR and XRD. The bionanocomposites showed change of color and appearance of cracks. As the mass loss, the BIO2,5 system presented loss of 22.5%, and the BIO5, of 25.9%, for 86 days of exposure in simulated soil. It was also observed by FTIR, a marked reduction in the intensity of the corresponding band to the C = O groups, indicating that microbial attack promoted cleavage of bonds of the ester group. By XRD, there was a decrease in the intensity of the peaks and enlargements thereof with increasing exposure time, demonstrating the biodegradation behavior of bionanocomposites.
Evaluation of Current in Composites PVAL/Ceramics for Detection of Leakage Current Generated in Electrical Insulators
Authors: Costa Jr. Ana Cristina S. , Menezes Patrícia Costa Fernandes , Andrade A.J.V. , Silva Thiago , Costa E.G. , Costa A.C.F.M.
Published: August 2016

This research aims to prepare composites of polyvinyl alcohol (PVAL) with ceramic nanoparticles loads (NPs) of Ti1.95Eu 0.05O2; ZnAl2O4 and Ni0.5Zn0.5Fe2O4 to evaluate the detection of leakage current generated in electrical insulator. The composites were prepared in the proportion of 6/1.5 g of the PVAL/ceramics and characterized by XRD, FTIR, SEM and measurements of the current as a function of applied voltage. The results show for the composites with Ti1.95Eu0.05O2 and ZnAl2O4 a homogeneous morphology, while the structure of the composite formed by Ni0.5Zn0.5Fe2O4 resulted in a heterogeneous and porous morphology. The determination of the current as a function of the applied voltage has shown that there is a dependence of morphology and the semiconductor characteristic of the load used and the best results are therefore assigned for the composite produced with the Ti1.95Eu0.05O2 load with homogeneous morphology and high current values as a function of the applied voltage.
Changes in Molecular Weight of Poly(Styrenesulfonate) Initiated by Thioxanthone: Photolysis and Photo-Oxidation
Authors: Osajima Josy Anteveli , Schmitt Cavalheiro Carla Cristina , Neumann Miguel Guillermo
Published: August 2016

The presence of dyes in colored polymers can cause a series of reactions that promote their photodegradation under irradiation. The aim of this study was to investigate the kinetic behavior of the photodegradation of poly (sodium 4-styrenesulfonate) (PSS) in aqueous solution or in the presence of thioxanthone (TX) under UV radiation in different atmospheres. These systems were monitored by SEC. The polydispersity decreased in all systems studied indicating that there was a breach of the polymer main chain. Only the PSS / TX / air atmosphere system peaked, which occured at 43h of irradiation. However, this system showed slower kinetics of polymeric scission due to the dye suppressing a transfer of energy from the triplet state to the polymer. The photodegradation of solutions of PSS / air atmosphere showed higher efficiency under ultraviolet radiation in relation to the PSS in the presence or absence of the dye under an inert atmosphere.
Processing of Pet-Silver Nanocomposite Filaments
Authors: Guerra Marcos Antônio , Mariano Neide Aparecida , Ramos Alfeu Saraiva , Campos Maria Gabriela Nogueira
Published: August 2016

Nanoparticles play a fundamental role on nanocomposite properties, as they significantly increase the contact area and allow a homogeneous distribution in comparison to microparticles. Silver nanoparticles (AgNP) have been extensively used in biomedical and engineering applications due to their interesting properties, such as antibacterial activity. Polyethylene terephthalate (PET) is a semi-crystalline polymer and has excellent chemical resistance and thermal stability. Because of its remarkable properties, PET has been used in several industrial applications, such as packaging, electrical, automotive, construction and textile. The aim of this study was to prepare potential antimicrobial PET-AgNP nanocomposite filaments for textile applications. Therefore, AgNP were incorporated in the PET matrix at different concentrations (0.05; 0.10; 0.15; 0.20; 0.25; 0.30; 0.35 and 0.40%) by extruding the PET resin with specific amounts of a 10% (w/w) AgNP/PET master batch. Then, rheological characterization was carried out and filaments were produced for mechanical, optical and thermal analyses. The incorporation of up to 0.20% (w/w) of AgNP in the polymeric matrix has not significantly altered overall properties of PET nanocomposites. Moreover, the nanocomposite incorporated with 0.05% of AgNP demonstrated suitable intrinsic viscosity for fiber processing and PET-like mechanical, thermal and optical properties.
Correlation between the Density and the Diameter of Fique Fibers
Authors: Amoy Netto Pedro , Altoé Giulio Rodrigues , Muylaert Margem Frederico , de Oliveira Braga Fabio , Monteiro Sergio Neves , Margem Jean Igor
Published: August 2016

Environmental considerations in addition to technical, economical and societal benefits are contributing to promote the substitution of natural fibers for glass fiber in polymer matrix composites. However, natural fibers are heterogeneous in their dimensions, specially the cross section diameter, which plays an important role in their physical properties. The fibers extracted from the leaf of the fique plant (Furcraea andina) are a promising stiff natural fiber for composite reinforcement. In this work, a statistical analysis of the density of fique fibers using the Weibull methodology was performed. An attempt to correlate the fiber density with the diameter, precisely measured by means of a profile projector, was carried out. The results revealed an inverse dependence, adjusted to a hyperbolic equation, between the fique fiber diameter and corresponding density.
Density Weibull Analysis of Pineapple Leaf Fibers (PALF) with Different Diameters
Authors: Oliveira Glória Gabriel , Altoé Giulio Rodrigues , Amoy Netto Pedro , Muylaert Margem Frederico , de Oliveira Braga Fabio , Monteiro Sergio Neves
Published: August 2016

Societal, economical, technical and environmental advantages are today justifying the replacement of synthetic fibers by natural fibers. However, natural fibers obtained from plants do not present the same dimensional uniformity. In fact, they show large dispersion of values, as compared to synthetic fibers. In the case of the lignocellulosic fiber extracted from the pineapple leaf, limited information exists regarding the correlation between its properties and dimensional characteristics. In particular, so far, no investigation has been carried out on the influence of the diameter and the density of pineapple fibers. Therefore, the objective of this work was to measure the density of pineapple fibers and to define, by means of the Weibull statistic method, its dependence on the corresponding fiber diameter.
Effect of the Fiber Equivalent Diameter on the Elastic Modulus of Eucalyptus Fibers
Authors: Barbosa Anderson de Paula , Muylaert Margem Frederico , Monteiro Sergio Neves , Oliveira Caroline Gomes , Tonini Simonassi Noan
Published: August 2016

Environmental, economical, societal and technical advantages are today favoring natural lignocellulosic fibers over glass fiber. However, natural fibers are not as uniform in their dimension and properties as compared to synthetic ones. In recent works, it was found that the variation in strength could be correlated to the diameter for several lignocellulosic fibers, including that obtained from the eucalyptus wood. The present work investigated a possible correlation of the diameter with changes in the elastic modulus of eucalyptus wood fibers. Precise measurements of the equivalent diameter, conducted in a profile projector, were correlated with the elastic modulus by means of the Weibull statistic analysis. The results showed that an inverse correlation with the diameter applies for the elastic modulus with a reasonable degree of precision. SEM observation of the eucalyptus fiber, both it its structure and fracture aspects, strongly indicates that defects and microfibrils participation could be responsible for the inverse correlation.
Obtaining of Ceramic Sensor Devices for Soil Humidity Measurements in Different Climatic Conditions
Authors: Oliveira Rodrigo de Matos , Nono Maria do Carmo de Andrade , Couto Manoela de Oliveira
Published: August 2016

Presently, there is a lack of effectiveness in the manufacturing of sensors and sensing systems, with Brazilian technologies and raw-materials, able to measure soil water content, with efficiency and practicality. On account of this, ceramics is selected as sensing elements for this application, based on relevant results obtained by researchers from the TECAMB Group of INPE, along the last 15 years. In this way, the present work tries to bring together the technologies of manufacturing, characterization and development of porous ceramics and the monitoring of soil water content in typical Brazil soils, for several applications, such as irrigation, drainage, building and environmental monitoring as well. And so, in order to improve the sensing capacity of these ceramic devices, electrical measurements were performed in different climatic conditions of controlled relative humidity and room temperature. The scanning electron microscopy technique was applied for the morphological analysis of the sintered ceramic microstructure. Results evidenced that the ceramic devices presented a very promising response to the water molecules contained in soil samples selected for tests, under established climatic conditions.
Influence of Martensitic Transformation on the Fatigue of Low Temperature Metastable Stainless Steel
Authors: Monteiro Sergio Neves , Scarpini Cândido Verônica , da Silva Luis Carlos , Muylaert Margem Frederico
Published: August 2016

The influence of martensitic transformation on the fatigue of AISI 316 type stainless steel, which presents a low temperature metastable behavior, was investigated at-196 and 25°C. Fatigue tests were conducted on both annealed and cold worked conditions. The results from stress versus number of cycles curves showed that the fatigue resistance is not affected by the “dynamically” induced martensite in annealed specimens at both temperatures. On the contrary, the previously induced “static” martensite in work hardened specimens contributes to decrease the fatigue resistance limit. The contribution of the martensite stability is discussed.
Evaluation of Martensite Fraction in 1026 Steel by Infrared Thermography Combined with the Koistinen-Marburger Model
Authors: Bubnoff Dimitry V. , Carvalho Mariana M.O. , Xavier Carlos Roberto , da Fonseca Gláucio S. , de Castro José Adilson
Published: August 2016

In the present work, the martensite formation during heat treatment of 1026 steel was studied in order to acquire process knowledge and reinforce the effectiveness of infrared thermography method to evaluate the temperature distributions. Several tests were carried out and monitored by an infrared camera and thermocouples. Martensite fraction was evaluated with the aid of the Koistinen-Marburger model and adequate parameters describing phase transformations were obtained for 1026 steel samples. This research revealed the need of model adjustment in order to accurately describe the martensite transformation kinetics according to experimental results.
Formation of Ni3Ta, Ni2Ta and NiTa by High-Energy Ball Milling and Subsequent Heat Treatment
Authors: Nunes Benites Hanna Stefanni , da Silva Bruna Pereira , Pinto da Silva Antonio Augusto Araújo , de Lima Belmira Benedita , Coelho Gilberto Carvalho , Ramos Alfeu Saraiva
Published: August 2016

The present work reports on the formation of Ni3Ta, Ni2Ta and NiTa by high-energy ball milling and subsequent heat treatment. The elemental Ni-25Ta, Ni-33Ta and Ni-50Ta (at.-%) powder mixtures were ball milled under Ar atmosphere using stainless steel balls and vials as well as 300 rpm and a ball-to-powder weight ratio of 10:1. Following, the as-milled samples were uniaxially compacted and heat-treated under Ar atmosphere at 1100°C for 4h. The characterization of as-milled and heat-treated samples was conducted by means of X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry techniques. Supersaturated solid solutions were formed during ball milling of the Ni-25Ta, Ni-33Ta and Ni-50Ta powders. A large amount of Ni3Ta, Ni2Ta and NiTa was formed in the mechanically alloyed heat-treated Ni-25Ta, Ni-33Ta and Ni-50Ta alloys, respectively.
Analysis of the Microstructural Evolution during the Transient Upward, Downward and Horizontal Directional Solidification of the Al-1.2wt%Pb Monotectic Alloy
Authors: Konno Camila Yuri Negrão , Vasconcelos Angela J. , Barros André Santos , Silva Adrina P. , da Rocha Otávio Fernandes Lima , Garcia Amauri , Spinelli José Eduardo
Published: August 2016

Monotectic alloys are of great industrial importance because of their favorable tribological behavior. Many studies in order to better understand the morphologies obtained by monotectic reaction have been developed. To better understand the morphologies obtained by monotectic Al-1.2wt%Pb alloy reaction, especially in relation to induced convective flow, this paper aims to compare the microstructural evolution of the alloy obteind by directional solidification in transient heat-flow conditions in upward, downwand and horizontal solidification devices. It was observed a morphology transition from particles to fibers on upward and downward cases and a morphology of only particles on the horizontal case. The classical relationship used for eutectic growth, λ2v = C, which was considered applicable to monotectic reactions, didn’t seemed to be valid in the interphase spacing evolution for the downward device, however power functions (λ = C.va) were found in all cases.
Static Aging Behavior of Microalloyed Wire Steel and Carbon Wire Steel
Authors: David Felipe Farage , David Sayd Farage , Lira Silveira Lucas , Ferreira Ricardo Arthur Sanguinetti
Published: August 2016

The reinforcing wire production CA-60 is highly relevant due to its wide application in concrete products (welded wire mesh and truss girder), driven by growing demand for products of the construction area. One of the properties required by ABNT / NBR 7480/07 is the yield stress (σe), which has a direct effect on the maximum load that the structural component may be subjected in service. The addition of steel wire temperature during cold rolling increases the σe and reduces the ductility due to the aging phenomenon. These variations occur due to the formation of solute atoms atmosphere around the dislocations. The purpose of this paper is to study the behavior of σe during heat treatment of static aging at 100 °C in the wire CA-60 steel made from the niobium microalloyed steel equivalent ASTM A913 and the equivalent ASTM 1013 steel. As a result the wire carbon steel 1013 showed the same variation of σe during static aging of niobium microalloyed steel A913. This phenomenon was justified because of the increased level of pro-eutectoid ferrite and grain size in the carbon steel 1013.
Sintered Nickel Casing for Irradiation Targets
Authors: Miyano R.S.L. , Takiishi H. , Soares E.P. , Saliba-Silva A.M. , Rossi J.L.
Published: August 2016

The aim of this work was to develop an alternative way to obtain casings used with irradiation targets containing uranium, for the production of the radionuclide Mo-99-Tc99m. The targets used for the production of Mo-99 are materials containing U-235 designed to be irradiated in a nuclear reactor. Usually these targets are encapsulated in aluminum or stainless steel. The idea here is to obtain casings by encapsulating a uranium button or a metallic cylinder with compacted and sintered nickel powder, this serving as a sealing for the fissile products occurring during U-235 irradiation. The sintered high purity nickel powder samples were compacted in uniaxial hydraulic press at 195 MPa. The sintering of the samples was carried out in an open-air furnace in an atmosphere with a certain control using titanium-machining chips at 600 °C. The samples bulk density was evaluated by the Archimedes' principle. The porosity of 20.08% was measured by mercury porosimetry. The microstructure was investigated by scanning microscopy revealing interconnected porosity and nickel oxide at the particles boundary surface. The results obtained by sintering of nickel powder according to the experimental undertaken, indicate the feasibility of achieving a casing for uranium targets.
Mechanical Behavior and Structural Analysis of a TiNi Alloy Annealled in the 300 to 500°C Range and Air Cooled
Authors: Matlakhova Lioudmila Aleksandrovna , Pessanha Everton Maick Rangel , de Carvalho Eduardo Atem
Published: August 2016

This work has as objectives the structural analysis and mechanical behavior of a TiNi (46.5Ti-53.5Ni (wt%) / 51.6Ti-48.4Ni (at%)) alloy displaying Shape Memory Effect, manufactured by Light Metals Institute, in Russia, as a ∅ 5.12 mm wire. Samples were annealed at 300 to 550oC, and air cooled afterwards. X-Ray and scanning electron microscopy structural analysis was performed. Mechanical tests by compression testing were made, up to 10% strain, with control unloading, and afterwards continued up to fracture. The alloy has shown itself sensitive to the heat treatment and applied strain. In the alloy, after annealing at different temperatures in the interval of 300 to 550oC, phases B19’, R and Ti2Ni, were identified. Along higher annealing temperatures, up to 550oC, R phase was replaced by B2. In this alloy, strain induced Martensitic Reversible Transformations (MRT) type B2/R→B19 ́/Rdef were induced.
Harder and Denser AlN-TiB2 Ceramic Composites Processed by Spark Plasma Sintering
Authors: Peçanha Jr. Luiz Antonio Fonseca , Simão Larissa , Skury Ana Lucia Diegues , Picanço Oliveira Michel , Tedesco Bolzan Lucas , Monteiro Sergio Neves
Published: August 2016

Aluminum nitride, AlN, and titanium diborite,TiB2, are covalent-based ceramics with wide technological applications. However, sintering of these ceramics using conventional methods of high pressure requires not only elevated temperatures but also long processing time. This causes excessive grain growth, which impairs strength and hardness. In the present work, 70%AlN-30%TiB2 ceramic composites were sintered to relatively higher density and hardness by means of the Spark Plasma Sintering (SPS) at temperatures in the interval from 1500 to 1900°C in order to improve the properties of both compounds and decrease the processing time. The SPS was applied for different sintering temperatures and the effects on density, hardness and surface structure were evaluated. Maximum values obtained for density and hardness were 98.8% of the theoretical value and 13.7 GPa, respectively.
Study of Aluminum Alloy 7050 T7451 Isotropic Hardening
Authors: Mendes Lima Rodrigo , Massaroppi Jr. Ernesto
Published: August 2016

This paper presents the yielding surface isotropic hardening study of the aluminum alloy 7050 T7451 submitted to monotonic loadings, considering the nonlinear constitutive model proposed by Voce. The stress state imposed characterizes a behavior whose plastic deformations cannot be neglected. The analysis depends on the segregation between the isotropic and the kinematic hardening that composes the material’s behavior during its transient life. Monotonic and cyclic tension-compression tests have been realized in order to allow the Bauschinger Effect understanding. The results have been compared to FEM simulations in order to validate the model.