bluuebunny/crossref_metadata_2025 huggingface dataset:
Tensile Strength of Polyester Composites Reinforced with Thinner Buriti Fibers
Authors: Monteiro Sergio Neves , Margem Frederico Muylaert , Altoé Giulio Rodrigues , Loiola Rômulo Leite , Oliveira Michel Picanço
Published: January 2014

The environmental concern is creating pressure for the substitution of energy intensive synthetic materials for natural and sustainable ones. Compared to synthetic fibers, natural fibers have shown advantages in technical aspects such as flexibility and toughness. So there is today a growing worldwide interest in the use of natural fibers. Buriti fiber extracted from the petiole of buriti palm tree (Mauritia flexuosa), presents some significant characteristic, but until now only few studies on buriti fiber were performed. This work aims to study the tensile strength of polyester composites reinforced with buriti fibers. This study was performed in relatively thinner fibers with diameters between 0.1 and 0.4 mm. Those fibers were incorporated into the polyester matrix with volume fraction from 0 to 30%. The fiber diameters were measured by a profile projector. After fracture the specimens were analyzed by scanning electron microscope (SEM). The results showed a sensible improvement in the mechanical properties. The SEM observation revealed the mechanism for this improvement.
Nanostructured Titanium Surface Obtained by Electrochemical Treatment
Authors: Antonini L.M. , Parise Karine , Witt A.R.S. , Savaris Israel Durli , Gustavo L. , Malfatti Célia de Fraga
Published: January 2014

Research on titanium and its alloys as biomaterials have been attracted the interest because of its clinical success, but they have been facing problems due to failures caused by tissue cohesion loss, fracture. Studies involving the influence of surface roughness of titanium implants on the osseointegration rate and biomechanical fixation have been develop. However, it is neessary to understand the effect of surface morphology on the osseointegration process. This paper aims to examine the effect of current density on the electropolishing process of Ti in order to obtain nanostructured surfaces. Ti samples were mechanically abraded and then subjected to electropolishing in acidic solution. After the electropolishing process, the samples were characterized by atomic force microscopy, profilometry and wettability tests. Preliminary results show that the increase on current density contributed to the decrease in nanoroughness of substrate yet it did not affect the surface wettability, which presented an hydrophilic behaviour.
Eucalyptus Chip Ashes in Cementitious Composites
Authors: de Resende Domingos Sávio , Radispiel Filho Herbet , Keles José Genário , Bezerra Augusto Cesar da Silva , Paulino Aguilar Maria Teresa , de Gouveia Antonio Maria Claret
Published: January 2014

The Alto Paranaiba and Triângulo Mineiro mesoregion in the state of Minas Gerais and the State of São Paulo have a number of industries with eucalyptus chip fired boilers that produce great amounts of ash. Since thermoelectric ashes generally have good pozzolanic activity, this paper studied the mechanical behavior of cementitious composites made with raw eucalyptus chip ash as a partial replacement for Portland cement and processed under two different conditions. The mechanical behavior of the composites was measured from tests on specimens for their compressive strength, tensile strength to diametral stress and to bending. Results show ashes could be used as mineral additives.
Thermal Characterization of Polyester Composites Reinforced with Ramie Fibers
Authors: Monteiro Sergio Neves , Margem Frederico Muylaert , Bevitori Alice , da Silva Isabela Leão Amaral , Oliveira Michel Picanço
Published: January 2014

Polyester composites reinforced with natural lignocellulosic fibers have attracted interest in several engineering areas due to their low cost, low energy consumption during fabrication in association with a number of possible applications. One of these applications is the replacement of traditional composites such as the fiberglass. Characterization of polyester composites incorporated with ramie fiber has recently been conducted for physical and mechanical properties. However, the effect of increasing temperature on these composites has not yet been fully investigated. Therefore, the objective of this study was to evaluate the thermogravimetric behavior of polyester composites reinforced with up to 30 vol% of ramie fibers. The analysis was conducted by TG and DTG techniques. The presence of ramie fibers induces sensible changes in the thermal stability of the polyester composites, showing a significant effect of the ramie fibers by reducing their temperatures of degradation.
Tensile Strength of Polyester Matrix Composites Reinforced with Giant Bamboo (Dendrocalmus giganteus) Fibers
Authors: Monteiro Sergio Neves , Muylaert Margem Frederico , de Souza Martins Lucas Barboza , Loiola Rômulo Leite , Oliveira Michel Picanço
Published: January 2014

Fibers of the giant bamboo (Dendrocalmus giganteus) are amongst the strongest lignocellulosic fibers. Although studies have been already performed, limited information exists on the mechanical properties of polymeric composites reinforced with continuous and aligned giant bamboo fibers. This work evaluates the tensile strength of this type of composite. Standard tensile specimens were fabricated with up to 30% of fibers aligned along the specimen length. The fibers were press-molded with a commercial polyester resin mixed with a hardener and cured for 24 hours at room temperature. The specimens were tensile tested in an Instron machine and the fracture surface analyzed by scanning electron microscopy. The tensile strength increased significantly with the amount of giant bamboo fiber reinforcing the composite. This performance can be associated with the difficult of rupture imposed by the fibers as well as with the type of cracks resulting from the bamboo fiber/polyester matrix interaction, which prevents rupture to occur.
Bending Mechanical Behavior of Epoxy Matrix Reinforced with Jute Fiber
Authors: Monteiro Sergio Neves , Margem Frederico Muylaert , da Silva Isabela Leão Amaral , Bevitori Alice , Oliveira Michel Picanço
Published: January 2014

Environmentally correct composites, made from natural fibers, are among the most investigated and applied materials today. In this paper, the mechanical behavior of epoxy matrix composites reinforced with continuous jute fiber was investigated through bending tensile tests. Specimens containing 0, 10, 20 and 30% in volume of jute fiber were aligned along the entire length of a mold to create plates of these composites. Those plates were cut following the ASTM standard to obtained bending tests specimens. The test was conducted in an Instron machine and the fractured specimens were analyzed by SEM. The results showed an increase in the materials tensile properties with the increase of fiber amount.
Izod Impact Tests with Polyester Matrix Reinforced with Buriti Fibers
Authors: Monteiro Sergio Neves , Muylaert Margem Frederico , Oliveira Michel Picanço , Altoé Giulio Rodrigues
Published: January 2014

The buriti palm tree (Mauritia flexuosa) has, in its petiole, natural fibers with great potential for reinforcement of polymer composites. This work attempts to evaluate the impact resistance of this type of fiber reinforcing polyester matrix. The fibers were mixed with polyester resin under pressure in a metallic mold, and cured at room temperature for 24 hours. Specimens were prepared with fiber percentages varying from 0 to 30% in volume. These specimens were tested in an Izod impact pendulum and the fracture surfaces were examined by scanning electron microscopy, SEM. The impact resistance increased substantially with the relative amount of buriti fiber reinforcing the composite. This performance was associated with the resistance imposed by the fibers and the crack propagation behavior.
Development of Phosphate Glass Microspheres Containing Holmium for Selective Internal Radiotherapy
Authors: Barros Eraldo C. , Sene F.F. , Martinelli J.R.
Published: January 2014

Selective internal radiotherapy is used to treat hepatocellular carcinoma. Glass microspheres containing β- particle emitter radionuclides are introduced into the liver close to the tumor. The microspheres are trapped in the arterioles which feed the tumor. The irradiation with β- particles can cause the death of cancer cells. In this work the development of phosphate glass microspheres containing holmium is proposed. 165Ho has a high cross section for neutron absorption enabling the production of 166Ho which decays to 166Er by emitting a β- particle. The microspheres were produced using the flame method and characterized by different techniques to evaluate their potential use in radiotherapy. Microspheres with suitable morphology, size, density, and holmium concentration were obtained.
Production of Synthetic Ornamental Marble as a Marble Waste Added Polyester Composite
Authors: Ribeiro Carlos Eduardo Gomes , Rodriguez Rubén Jesus Sanchez , Vieira Carlos Mauricio Fontes , de Carvalho Eduardo Atem , Candido Veronica Scarpini , Monteiro Sergio Neves
Published: January 2014

The worldwide demand for ornamental stones in building construction is motivating the use of their wastes, generated during fabrication, to produce synthetic stones. This work has as its objective to investigate the production of a synthetic ornamental marble (SOM) under vacuum and vibro-compression processing of a polyester matrix composite with addition of marble waste as a filler. Rectangular SOM composite plates were subjected to compression and flexural mechanical tests. Samples were analyzed to obtain the density, water absorption, and microstructure. The SOM composites presented properties within the expected range of an artificial stone, which indicates that the applied process is suitable for production of this type of material.
Particle Size Study of Smectite Clays from the City of Pedra Lavrada-PB
Authors: Cardoso Mirtys Allamana Ferreira , Chaves Alexsandra Cristina , Dantas M.M. , da Silva Isabelle Albuquerque , Pereira I.D.S. , Neves Gelmires Araújo , Ferreira Heber Carlos
Published: January 2014

The state of Paraíba disposes of one of the largest deposits of smectites in the country. However, these smectites present in their composition elevated contents of accessory minerals, especially quartz. For these clays to become viable to determine technological use it is necessary the elimination of part of these minerals. The particle size analysis of a soil consists in the determination of the size of the particles that constitute it and their distribution in certain intervals. This work aims to study smectite clays from the city of Pedra Lavrada-PB, through the particle size analyses, for the use in water based drilling fluids. The determination of particle size was made by sieving and laser granulometer. Apparent and plastic viscosities were measured from the samples. The clays were left at rest before the test for periods of 7 and 28 days, with and without deflocculant. It was verified that there was no significant difference in the particle sizes in relation to the resting time of the samples.
The Influence of Calcination Temperature in Ni-Zn Ferrite Doped with Al3+
Authors: Santos Polyana Tarciana Araújo , Dantas J. , Araújo P.M.A.G. , Santos P.T.A. , Costa A.C.F.M.
Published: January 2014

Ferrites are ceramic materials whose magnetic properties are very interesting used in various applications. This study evaluates the calcination on the characteristics of Ni0.5Zn0.5Fe1.97Al0.3O4 ferrites synthesized by combustion reaction. The samples as synthesized and after calcination at 700 oC/1h in a muffle type furnace were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, magnetic measurements and determination of carbon content. The results showed the formation of the Ni0.5Zn0.5Fe2O4 ferrite phase for samples with and without calcination. The infrared spectra showed characteristic vibrations of HO and NO bonds, possibly attributed to the adsorbed water and residual nitrate. Morphologically there was the formation of soft agglomerates with interparticule porosity for both samples. The Ni-Zn ferrite doped with 0.3 mol of Al3+ showed superparamagnetic behavior without calcination and after calcination observing its behavior as a soft magnetic material (easy magnetization and demagnetization). Samples showed very low carbon content, indicating that urea used as a fuel was nearly completely consumed in the reaction and after calcination it wasnt observed the presence of carbon.
Synthesis, Characterization and Catalytic Performance of Nanoferrites Subjected to the Esterification Reaction
Authors: Silva Adriano Santana , Dantas Joelda , Santos J.R.D. , Cunha R.B.L. , Kiminami R.H.G.A. , Costa A.C.F.M.
Published: January 2014

Ni0.5Zn0.5Fe2O4, Mn0.5Zn0.5Fe2O4and Ni0.2Cu0.3Zn0.5Fe2O4nanoferrites were synthesized, characterized and evaluated in terms of their performance as catalysts in the methyl esterification reaction of soybean oil. The nanoferrites were synthesized by combustion and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The XRD patterns show the presence of inverse spinel B(AB)2O4phase. The EDX results confirmed the stoichiometry of the nanoferrite systems, whose morphology consisted of large block-like agglomerates with a brittle aspect and a wide agglomerate size distribution. The results indicate that the Ni0.5Zn0.5Fe2O4nanoferrite was the most active catalyst in the esterification reaction, with conversion rates ranging from 40 to 91%.
Evaluation of the Relationship between Crystallographic Texture and Magnetic Properties through the Magnetocrystalline Anisotropy Coefficient
Authors: Felix R.A.C. , Brandão Luiz , da Cunha M.A. , Paiva C.H.P. , Amaro J.R.L. , Teles Lucas S. , da Rosa Ricardo Luiz O. , Júnior R.P.G. , Saldanha Thiago A. , Bezerra Victor Hugo G.
Published: January 2014

It is well known that iron has a magnetocrystalline anisotropy and, therefore, the crystallographic texture has great influence on its magnetic properties. In most applications of non-oriented grain electrical steels, it is desirable that the magnetic properties are isotropic. In this work, modern quantitative texture analysis methods are used to characterize the crystallographic textures of many types of non-oriented grain electrical steels and their relation with the magnetic properties. The magnetocrystalline anisotropy coefficient is the parameter of texture analysis that is directly related to the magnetic properties. This paper analyzes the correlation between the magnetic properties of electrical steels with 3 wt.% to 5 wt.% silicon and their magnetocrystalline anisotropy coefficients.
Nucleation as Coercivity Mechanism in NdFeB Magnets
Authors: de Campos Marcos Flavio
Published: January 2014

In the first part of this article, the SW-CLC (Stoner-Wohlfarth with CLC modification) model is discussed for nanocrystalline magnets, as melt-spun exchange coupled NdFeB. In the second part, the effect of grain size of coercivity for large grain size, above the single domain particle size, is addressed. The Kondorsky law observed for large grain size only can be due to domain wall displacement phenomena, where there is nucleus expansion. There are two main situations, one for nanocrystalline grain size, where the SW-CLC model is obeyed, and other for large grain size, where the coercive field decreases proportionally to the square root of the grain size.
Study of Morphology Membrane of Polymeric Nanocomposites Obtained by Phases Inversion
Authors: Medeiros Keila Machado , Silva Taciana Regina de Gouveia , Morais Dayanne Diniz Souza , Kojuch Luana Rodrigues , Araújo Edcleide Maria , Lira Hélio Lucena
Published: January 2014

In this work, were obtained nanocomposite membranes polyamide66/Paraíba bentonite clay, treated with a quaternary ammonium salt in order to make it organophilic. The membranes were prepared as thin films using the technique of phase inversion from the nanocomposites obtained by solution. The membranes were characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). By means of X-ray diffractogram, it was revealed that the membranes remained organically treated clay presented exfoliated and/or partially exfoliated structure. From curves of DSC and TG, it was observed that membrane of PA66 with 3% w/w of with treatment clay showed higher thermal stability compared with the same content of clay without treatment. From the SEM photomicrographs, there was a selective layer (skin filter) on top and one porous layer at the bottom of all membranes studied. Moreover, it was verified that the presence of clay provided a significant structural modification in the membranes of polymer nanocomposites.
Evaluation of the Thermal Stability of Biofuel Obtained from Oil Plant Pyrolysis and Animal Fat
Authors: Filho Francisco Ferreira Dantas , da Silva Morais Crislene Rodrigues , Chaves Alexsandra Cristina , Barros Adrianne T. , Souza M.A.F. , Trajano Luciano L.
Published: January 2014

The present study reports obtaining biofuel by pyrolysis of plant oil and animal fat. This process consists in breaking of molecules at high temperatures, obtaining hydrocarbons, similar to oil, and oxygenates such as esters, carboxylic acids, aldehydes, etc. The research aimed to evaluate the thermal and kinetic behaviour and the heat of combustion of bio-oil and bio-oil mixtures / diesel oil. In this work, Thermogravimetric studies were performed (TG) at a heating rate of 10 ° C min-1 under air atmosphere synthetic, Thermodynamic studies (ΔH, ΔS and ΔG) and about heat of combustion also were done. Thermal stability at 30°C was observed from thermogravimetric study. The kinetic calculations were performed in order to observe parameters such as activation energy (Ea) and Arrhenius factor.
Influence of Quartzite Residues on the Strength of Added Red Clay Ceramics
Authors: Babisk Michelle Pereira , Ribeiro Wagner Souza , de Aguiar Mariane Costalonga , Candido Veronica Scarpini , Gadioli Monica Castoldi Borlini , Monteiro Sergio Neves , Vieira Carlos Maurício Fontes
Published: January 2014

The incorporation of industrial residues into red clay ceramics has in past decades been used not only as a search for the alternative use of lower cost raw-materials but also an environmentally correct way of destination of polluting wastes. This work had as its objective to study the influence of incorporation of a quartzite stone residue on the mechanical strength of a red clay ceramic. Clay bodies were prepared with up to 40 wt% of the residue. These clay bodies were then uniaxially press-molded and sintered at 800 and 1050oC. The strength was evaluated by three points bend tests. The microstructural analysis was conducted by means of both optical and scanning electron microscopes. A tendency for decreasing the strength was found with the amount of incorporated residue. This was a consequence of the inert characteristic of the quartz, which is the predominant mineral in the quartzite stone, as well as the possible effect of cracks nucleated during the quartz allotropic transformation.
Incorporation of Granite Waste from Diamond Wire Sawing Process into Cement Matrix Concrete
Authors: Gonçalves Pedroti Leonardo , Vieira Carlos Maurício Fontes , Monteiro Sergio Neves , Candido Veronica Scarpini , Xavier Gustavo de Castro , Alexandre Jonas
Published: January 2014

As one of the world leading producers of natural stones for ornamental purpose, mainly marble and granite, Brazil also generates an increasing amount of corresponding wastes. Several alternatives have locally been proposed for the application of these wastes, including the incorporation into cement matrix concretes. In the present work a granite waste, generated by a sawing system composed of sintered diamond in the form of cylindrical beats attached to a steel wire, was incorporated into a cement matrix to be used as building construction concrete. These cement concretes incorporated with up to 30 wt% of granite waste were evaluated in terms of mechanical and chemical properties as well as their environmental impact. The results indicated that 20 wt% incorporation would be a limit for a concrete with acceptable technical characteristics and safe environmental risks.
Mechanichal Properties of DGEBA/TEPA Modified Epoxy Resin
Authors: Amaral Camila Rodrigues , Rodriguez Ruben Jesus Sanchez , Bessa Magno Luiz Tavares , Cândido Verônica Scarpini , Monteiro Sergio Neves
Published: January 2014

The correlation between the structural network of a diglycidyl ether of the bisphenol-A (DGEBA) epoxy resin, modified by two distinct aliphatic amines (tetraethylenepentamine TEPA and jeffamine D230), and its mechanical properties, was investigated as possible matrix for abrasive composites applications. Both flexural tests, to determine the yield stress and the elastic modulus, as well as impact tests to determine the notch toughness, were performed. The DGEBA/D230 presented the highest stiffness and toughness but lowest yield stress. This epoxy network also displayed a greater plastic deformation during fracture.
Analysis of the Properties of Asphaltic Concrete Using Recycled Aggregates of CDW
Authors: Brasileiro Luzana Leite , Silva Filho Edson Cavalcanti , Filho José Antônio Ramos da Costa , Vieira Pablo de Abreu , de Matos José Milton Elias
Published: January 2014

This study aims at investigating the feasibility of the partial replacement of aggregates of asphaltic concrete by recycled aggregates from construction and demolition waste (CDW). It was adopted as parameter a project design mixture of an asphalt concrete used in the construction of Itaueira-Canto do Buriti state highway (Piaui). Two project mixtures were used: in the first 38% of the natural aggregate were replaced by the recycled aggregate and in the second, 70%. We carried out the characterization of the aggregates through physical, chemical and mechanical testing analyzing them based on specific reference standards of paving. We performed assays related to the asphaltic mixture with CDW determining the apparent specific mass, the volume of voids, the relationship bitumen/voids and mechanical testing of traction resistance by diametric compression and Marshall Stability. The results indicate that the recycled aggregate, in a defined proportion, can partially replace natural aggregate in flexible pavements.
Clay Ceramic Incorporated with Granite Waste Obtained from Diamond Multi-Wire Sawing Technology
Authors: de Aguiar Mariane Costalonga , Gadioli Monica Castoldi Borlini , Babisk Michelle Pereira , Candido Veronica Scarpini , Monteiro Sergio Neves , Vieira Carlos Maurício Fontes
Published: January 2014

The technology of subdividing stone blocks by diamond multi-wire sawing has recently been used by the ornamental stone industrial sector in the state of Espirito Santo, southeast of Brazil. The waste generated by this sawing procedure is iron free and relatively clean as compared to other stone processing operations. In principle, the diamond multi-wire sawn waste could be a viable alternative of incorporation into clays ceramics. The possibility of incorporating up to 40 wt% of a granite waste generated from diamond multi-wire sawing into clay ceramics, fabricated in the neighbor state of Rio de Janeiro, was investigated in this work. The incorporated ceramics were fired at 750, 950 and 1050oC. The apparent density, liner shrinkage and flexural strength were evaluated. The results indicated that the incorporation of the waste improved the ceramic properties, particularly at 1050oC.
Development of Ceramic Refractory Filters from Alternative Mineral Source: Rheological Characterization
Authors: Carvalho Anelise Cristina , de Moraes Graziela Guzi , Cesconeto Francielly R. , Raupp-Pereira Fabiano , de Oliveira A. Pedro Novaes
Published: January 2014

This article reports the results of a preliminary research work related to the rheological study of aqueous suspensions prepared from an industrial solid waste (ceramic shell) from the process of lost-wax casting. The results showed that the residue analyzed has a strong refractory character since it contains mostly mullite, zirconium silicate and quartz. The ceramic suspensions obtained, containing 70% (~ 23% vol.) residue, 5-7% of kaolin and 1.0-1.5% dispersant, showed a rheological behavior suitable for impregnation of polymeric foams for the production of filters for metal casting by the replication method.
Citrate-Hydrothermal Synthesis and Electrochemical Characterization of La0.6Sr0.4Co0.2Fe0.8O3 for Intermediate Temperature SOFC
Authors: Garcia Laurenia M. Pereira , Souza Graziele L. , Nascimento Rubens M. , Macedo Daniel A. , Motta Fabiana V. , Paskocimas Carlos A.
Published: January 2014

Lanthanum cobaltites doped with strontium and iron (La1-xSrxCo1-yFeyO3) have been intensively studied as cathode materials for solid oxide fuel cells (SOFC). In this work, powders of composition La0.6Sr0.4Co0.2Fe0.8O3 (LSCF6428) were synthesized by a combination of citrate and hydrothermal methods. As-prepared and calcined powders were investigated by different material characterization techniques. LSCF films were obtained on gadolinium doped ceria substrates (CGO) after sintering at 1200 °C. The effects of the sintering conditions on the microstructure and electrochemical performance of the electrodes were evaluated by scanning electron microscopy and impedance spectroscopy. The electrochemical characterization was assessed using a symmetrical cell configuration (LSCF/CGO/LSCF) at temperatures ranging from 650 to 800 °C. The area specific resistance showed strong relationship with microstructure. The best electrochemical behavior (0.18 ohm.cm2 at 800 °C) was obtained by using sintering dwell time of 2 h.
Combustion Synthesis of the MgAl2O4 Using Glycerin from the Production of Biodiesel
Authors: de Moraes Graziela Guzi , Bonin Luiza , de Moraes Elisangela Guzi , Donadel Karina , Barp Kaio , de Oliveira Antonio Pedro Novaes
Published: January 2014

This work aims to investigate the glycerin from the biodiesel as fuel in the combustion synthesis into two routes, one for high temperature called direct route, in order to inhibit the formation of acrolein and compare it with the conventional combustion synthesis at low temperatures, using as fuels saccharose, pure glycerin, pure glycerin gel, glycerin from biodiesel, biodiesel from glycerin dried 24 h, biodiesel from glycerin gel dried 24 h to obtain the magnesium aluminate spinel (MgAl2O4). The synthesis was performed from the mixture of the precursors (Al (NO3)3.9H2O and Mg (NO3)2.6H2O) in water with the addition of the fuels. In the direct route case, the mixture was placed in a furnace heated to 500°C followed by calcination at different temperatures for 2 h. In the conventional route cases, the mixtures were slowly heated to 800°C for 2 h. The obtained powders, product of the combustion reactions, were characterized by X-ray diffraction (XRD), laser scattering particle size analyzer and scanning electron microscopy (SEM). The results showed that the product (powder) obtained by direct reaction was the MgAl2O4 as the only crystalline phase formed with particle sizes of approximately 41 μm. Even so, small particles with sizes of about 30 nm were also observed according to measurements on SEM images.
Microstructural Analysis of Clay Ceramic Added with Blast Furnace Sludge
Authors: Riter Aline Vieira , Vieira Carlos Maurício Fontes , Candido Veronica Scarpini , Monteiro Sergio Neves
Published: January 2014

The microstructure of a clay ceramic added with blast furnace sludge, a residue generated at integrate steel making plants, has been analyzed. This analysis was performed by means of optical microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy. The green clay body was added with 5 and 10 wt% of blast furnace sludge. A pure clay body was also considered as reference. These clay bodies were fired at 750°C and 950°C. The results indicated that the ceramic microstructure is non-uniform with both residue particles and pores dispersed throughout the clay matrix. Microcracks are also observed as a consequence of weak adhesion of the residue to the clay. At the higher firing temperature of 950°C the microstructure displayed a smoother surface due to the formation of low melting phases.
Thermal Treatment Related Structure and Property Changes in a TiNi Alloy Presenting Shape Memory Effect
Authors: Pessanha Everton Maick Rangel , Matlakhova Lioudmila Aleksandrovna , Paes Herval Ramos , Rodriguez Ruben Jesus Sanchez , Candido Veronica Scarpini , Monteiro Sergio Neves
Published: January 2014

Changes in the structure and properties of a TiNi alloy, which possesses shape memory effect by means of reversible martensitic transformation (RMT), after annealing at different temperatures in the interval of 300 to 550oC, were investigated. These changes were characterized by chemical analysis, X-ray diffraction, electrical resistivity, microhardness and differential scanning calorimetry. The results showed that the as-fabricated TiNi alloy presented a multiphase structure. An additional high temperature phase was revealed upon 550oC annealing. The alloy displayed sensible changes in its electrical resistivity that were attributed to the influence of the several existing phases. A tendency for the increase in the RMT critical temperatures was also observed with increasing annealing temperature.
Magnetic Modified Natural Polymers for Biotechnological Application
Authors: Carvalho Elaine Aparecida Santos , Rodriguez Ruben Jesus Sanchez , de Freitas Boa Morte Ellen , de Freitas e Castro Mayara , Marum Darlan Silveira , Candido Veronica Scarpini , Monteiro Sergio Neves
Published: January 2014

Magnetic microparticles were formulated by encapsulating magnetite nanoparticles with cellulose acrylamidemetyl propionate acetate (CAPA) chemically modified with acrylamide (AM) in order to immobilize, through covalent bonds, enzymes. The microparticles were characterized by means of scanning electron microscopy and thermogravimetry. The magnetic CAPA + AM microparticles display a quite regular spherical geometry with smooth surface and a magnetite load corresponding to 11.2% of the total mass. These particles were considered as convenient supports for enzyme immobilization in biodiesel transesterification process.
Adsorption of the Blue Dye Reactive Remazol RN in Cellulosic Materials
Authors: Rosa Mirna Sales Loiola , Silva Marcos Pereira , Morais Alan Icaro , Santos Maria Rita de Morais Chaves , Silva Filho Edson Cavalcanti , Santos Jr. Luiz Sousa
Published: January 2014

The disposal of textile waste in water bodies is exacerbating environmental problems, which led scientists to seek natural materials to develop more sustainable ways. Searching for low cost materials was used to remove the dye in two cellulosic sources (filter papers of different brands). The papers were characterized by XRD which confirmed crystallographic profile similar to cellulose. With the aim of optimizing the best conditions, various tests were performed, where the ideal time was 180 minutes for the paper 1 and 240 minutes for the second paper, both by adjusting the pseudo second-order model. The other parameters studied was the pH, adsorbate-adsorbent systems which have maximum adsorption capacity of 2.76 mg / g at pH 2.02 and 2 mg / g at pH 11 for the paper 1 and 10.57 mg / g pH 4 and 2 mg / g at pH 11 for the paper 2. Both adsorbents had the best fit to the Langmuir model in pHs 2 and 11 at the temperature of 298 K.
Effect of the Addition of TiO2 Nanoparticles on the Sinterability of a Glass Belonging to the LZSA Glass-Ceramic System
Authors: Cesconeto Francielly Roussenq , de Moraes Graziela G. , Neto João Batista Rodrigues , Raupp-Pereira Fabiano , Hotza Dachamir , de Oliveira Antonio Pedro Novaes
Published: January 2014

In this work aqueous ceramic suspensions were prepared from a parent glass-ceramic powder (3.8 μm) belonging to the LZSA (Li2O-ZrO2-SiO2-Al2O3) system without or with additions of different volume fractions (1.0-7.5%) of TiO2nanoparticles (25 nm). The obtained suspensions were rheologically characterized so that stable suspensions were defined e formed by slip casting. The obtained compacts were sintered (850-950°C/60 min) and their green and sintered densities were determined and related to linear shrinkage measurements. The results showed that samples sintered at 950oC for 60 min with 1.0% TiO2addicted presented linear shrinkage of 12% and relative densities of 97%.
The Role of Worker Tenure and Employment Heterogeneity on Software Development Work Activities
Authors: Crawford Jeff , Leonard Lori N. K. , Jones Kiku
Published: January 2014

Software development group effectiveness depends on many factors, and understanding those factors is vital to project success, especially when considering the time and money that is dedicated to said projects. Therefore, this study examines the role of worker tenure and employment heterogeneity on exploration and exploitation work completed within an organization’s software development group. Analysis of time tracking data within one financial services organization over a three years period demonstrates that worker tenure and employment heterogeneity do play an important role in shaping work activities. Worker tenure exhibited a negative relationship with exploration and exploitation activities, suggesting a critical mechanism through which an organization can elicit innovative and incremental development efforts. Further, the positive effect of employment heterogeneity on exploration and exploitation suggests that employment diversity can also provide a means to encourage innovative and incremental development activities. Findings highlight the notion that group composition plays a meaningful role in shaping the focus of software development work within an organization.
Metamodel of the IT Governance Framework Cobit
Authors: Souza Neto Joao , Neto Arthur Nunes Ferreira
Published: January 2014

This paper addresses the generation and analysis of the COBIT 4.1 ontological metamodel of IT Governance framework. The ontological metamodels represent the logical structures and fundamental semantics of framework models and constitute adequate tools for the analysis, adaptation, comparison and integration of IT best practice frameworks. The MetaFrame methodology used for the construction of the COBIT metamodel is based on the discipline of conceptual metamodeling and on the extended Entity/Relationship methodology. It has an iterative process of construction of the metamodel’s components, using techniques of modeling and documentation of information systems. In the COBIT 4.1metamodel, the central entity type is the IT Process. The entity type of IT Domain represents the four domains that group one or more IT processes of the COBIT 4.1. In turn, these domains are divided into one or more Activities that are carried through by one or more Roles which are consulted, informed, accounted for or liable for each Activity. The COBIT 4.1 metamodel may suggest adaptation or implementation of a new process within the framework or even contribute to the integration of frameworks, when, after the processes of analysis and comparison, there are connection points between the components and the logical structures of its relationships.
Impacts of a Relationship Model on Informational Technology Governance: an Analysis of Managerial Perceptions in Brazil
Authors: Scheeren Adriano Weber , Fontes Filho Joaquim Rubens , Tavares Rodrigues Elaine Maria
Published: January 2014

The aim of this article is to analyze the impacts, based on the perceptions of managers, of the deployment of a model to govern the relationship between business areas and IT in a large Brazilian financial organization. To undertake the case study of this deployment, the research firstly performed documental analyses of the process and then sent electronic surveys to a sample of managers in order to evaluate their perceptions of the model’s impact in terms of the formalism of the organization’s internal processes, strategic alignment between business areas and IT and levels of governance in the organization. The results revealed that managers perceived improvements in the quality of technological solutions, levels of IT governance, the understanding of IT area needs and business area demands, but they also stated that the negotiating process was more complex and there was no increase in their level of satisfaction with IT. These results of the study may contribute to the development of instruments for the evaluation of the impacts of the deployment of relationship models on important organizational aspects.
Global carbon monoxide products from combined AIRS, TES and MLS measurements on A-train satellites
Authors: Warner J. X. , Yang R. , Wei Z. , Carminati F. , Tangborn A. , Sun Z. , Lahoz W. , Attié J.-L. , El Amraoui L. , Duncan B.
Published: January 2014

Abstract. This study tests a novel methodology to add value to satellite data sets. This methodology, data fusion, is similar to data assimilation, except that the background model-based field is replaced by a satellite data set, in this case AIRS (Atmospheric Infrared Sounder) carbon monoxide (CO) measurements. The observational information comes from CO measurements with lower spatial coverage than AIRS, namely, from TES (Tropospheric Emission Spectrometer) and MLS (Microwave Limb Sounder). We show that combining these data sets with data fusion uses the higher spectral resolution of TES to extend AIRS CO observational sensitivity to the lower troposphere, a region especially important for air quality studies. We also show that combined CO measurements from AIRS and MLS provide enhanced information in the UTLS (upper troposphere/lower stratosphere) region compared to each product individually. The combined AIRS–TES and AIRS–MLS CO products are validated against DACOM (differential absorption mid-IR diode laser spectrometer) in situ CO measurements from the INTEX-B (Intercontinental Chemical Transport Experiment: MILAGRO and Pacific phases) field campaign and in situ data from HIPPO (HIAPER Pole-to-Pole Observations) flights. The data fusion results show improved sensitivities in the lower and upper troposphere (20–30% and above 20%, respectively) as compared with AIRS-only version 5 CO retrievals, and improved daily coverage compared with TES and MLS CO data.
Towards multi-tracer data-assimilation: biomass burning and carbon isotope exchange in SiBCASA
Authors: van der Velde I. R. , Miller J. B. , Schaefer K. , van der Werf G. R. , Krol M. C. , Peters W.
Published: January 2014

Abstract. We present an enhanced version of the SiBCASA photosynthetic/biogeochemical model for a future integration with a multi-tracer data-assimilation system. We extended the model with (a) biomass burning emissions from the SiBCASA carbon pools using remotely sensed burned area from Global Fire Emissions Database (GFED) version 3.1, (b) a new set of 13C pools that cycle consistently through the biosphere, and (c), a modified isotopic discrimination scheme to estimate variations in 13C exchange as a~response to stomatal conductance. Previous studies suggest that the observed variations of atmospheric 13C/12C are driven by processes specifically in the terrestrial biosphere rather than in the oceans. Therefore, we quantify in this study the terrestrial exchange of CO2 and 13CO2 as a function of environmental changes in humidity and biomass burning. Based on an assessment of observed respiration signatures we conclude that SiBCASA does well in simulating global to regional plant discrimination. The global mean discrimination value is 15.2‰, and ranges between 4 and 20‰ depending on the regional plant phenology. The biomass burning emissions (annually and seasonally) compare favorably to other published values. However, the observed short-term changes in discrimination and the respiration 13C signature are more difficult to capture. We see a too weak drought response in SiBCASA and too slow return of anomalies in respiration. We demonstrate possible ways to improve this, and discuss the implications for our current capacity to interpret atmospheric 13C observations.
Contrasts between estimates of baseflow help discern multiple sources of water contributing to rivers
Authors: Cartwright I. , Gilfedder B. , Hofmann H.
Published: January 2014

Abstract. This study compares baseflow estimates using chemical mass balance, local minimum methods, and recursive digital filters in the upper reaches of the Barwon River, southeast Australia. During the early stages of high-discharge events, the chemical mass balance overestimates groundwater inflows, probably due to flushing of saline water from wetlands and marshes, soils, or the unsaturated zone. Overall, however, estimates of baseflow from the local minimum and recursive digital filters are higher than those based on chemical mass balance using Cl calculated from continuous electrical conductivity measurements. Between 2001 and 2011, the baseflow contribution to the upper Barwon River calculated using chemical mass balance is between 12 and 25% of the annual discharge with a net baseflow contribution of 16% of total discharge. Recursive digital filters predict higher baseflow contributions of 19 to 52% of discharge annually with a net baseflow contribution between 2001 and 2011 of 35% of total discharge. These estimates are similar to those from the local minimum method (16 to 45% of annual discharge and 26% of total discharge). These differences most probably reflect how the different techniques characterise baseflow. The local minimum and recursive digital filters probably aggregate much of the water from delayed sources as baseflow. However, as many delayed transient water stores (such as bank return flow, floodplain storage, or interflow) are likely to be geochemically similar to surface runoff, chemical mass balance calculations aggregate them with the surface runoff component. The difference between the estimates is greatest following periods of high discharge in winter, implying that these transient stores of water feed the river for several weeks to months at that time. Cl vs. discharge variations during individual flow events also demonstrate that inflows of high-salinity older water occurs on the rising limbs of hydrographs followed by inflows of low-salinity water from the transient stores as discharge falls. The joint use of complementary techniques allows a better understanding of the different components of water that contribute to river flow, which is important for the management and protection of water resources.
The impact of uncertain precipitation data on insurance loss estimates using a Flood Catastrophe Model
Authors: Sampson C. C. , Fewtrell T. J. , O'Loughlin F. , Pappenberger F. , Bates P. B. , Freer J. E. , Cloke H. L.
Published: January 2014

Abstract. Catastrophe risk models used by the insurance industry are likely subject to significant uncertainty, but due to their proprietary nature and strict licensing conditions they are not available for experimentation. In addition, even if such experiments were conducted, these would not be repeatable by other researchers because commercial confidentiality issues prevent the details of proprietary catastrophe model structures from being described in public domain documents. However, such experimentation is urgently required to improve decision making in both insurance and re-insurance markets. In this paper we therefore construct our own catastrophe risk model for flooding in Dublin, Ireland in order to assess the impact of typical precipitation data uncertainty on loss predictions. As we consider only a city region rather than a whole territory and have access to detailed data and computing resources typically unavailable to industry modellers, our model is significantly more detailed than commercial products. The model consists of four components, a stochastic rainfall module, a hydrological and hydraulic flood hazard module, a vulnerability module and a financial loss module. Using these we undertake a series of simulations to test the impact of driving the stochastic event generator with four different rainfall data sets: ground gauge data, gauge corrected rainfall radar, meteorological re-analysis data (ERA-Interim) and a satellite rainfall product (CMORPH). Catastrophe models are unusual because they use the upper three components of the modelling chain to generate a large synthetic database of unobserved and severe loss-driving events for which estimated losses are calculated. We find these loss estimates to be highly sensitive to uncertainties propagated from the driving observational datasets, suggesting that the range of uncertainty within catastrophe model structures may be greater than commonly believed.
Estimation of permeability of a sandstone reservoir by a fractal and Monte Carlo simulation approach: a case study
Authors: Vadapalli U. , Srivastava R. P. , Vedanti N. , Dimri V. P.
Published: January 2014

Abstract. Permeability of a hydrocarbon reservoir is usually estimated from core samples in the laboratory or from well test data provided by the industry. However, such data is very sparse and as such it takes longer to generate that. Thus, estimation of permeability directly from available porosity logs could be an alternative and far easier approach. In this paper, a method of permeability estimation is proposed for a sandstone reservoir, which considers fractal behavior of pore size distribution and tortuosity of capillary pathways to perform Monte Carlo simulations. In this method, we consider a reservoir to be a mono-dispersed medium to avoid effects of micro-porosity. The method is applied to porosity logs obtained from Ankleshwar oil field, situated in the Cambay basin, India, to calculate permeability distribution in a well. Computed permeability values are in good agreement with the observed permeability obtained from well test data. We also studied variation of permeability with different parameters such as tortuosity fractal dimension (Dt), grain size (r) and minimum particle size (d0), and found that permeability is highly dependent upon the grain size. This method will be extremely useful for permeability estimation, if the average grain size of the reservoir rock is known.
Ricœur et Deleuze, lecteurs de Spinoza: Ontologie, éthique, imagination
Authors: Possati Luca M.
Published: January 2014

Cet article se propose de mettre en œuvre une lecture de Ricœur et Deleuze à partir de leurs interprétations respectives de la pensée de Spinoza. Ricœur et Deleuze se placent au centre de la Spinoza-Renaissance qui a eu lieu en France dans les années 1950-1960. Cependant, le ''spinozisme'' de Ricœur reste encore largement méconnu. Les deux premières parties de l'article se penchent sur les notions spinozistes de conatus et d'essentia actuosa, en soulignant ainsi leur importance et leur signification dans le cadre de l'herméneutique des symboles de Ricœur, surtout en relation avec sa lecture de Jean Nabert. Les trois parties suivantes sont consacrées à Deleuze, et notamment au rôle du spinozisme dans la genèse de l'ontologie rhizomatique de Mille plateaux. La dernière partie de l'article cherche à explorer la piste d'un dialogue possible entre Ricœur et Deleuze