bluuebunny/crossref_metadata_2025 huggingface dataset:
Recycling of Zircaloy Machining Chips by VAR Remelting and Powder Metallurgy Techniques
Authors: Takiishi Hidetoshi , Duvaizen J.H. , Sato I.M. , Rossi J.L. , Pereira L.A.T. , Martinez Luís Gallego
Published: August 2012

In the fabrication of nuclear reactor core parts, machining chips of Zircaloy are generated. These alloys are strategic for nuclear technology and cannot be discarded. In the present work are presented two methods for recycling of Zircaloy chips. One of the methods is by melting in VAR furnace and the other by powder metallurgy method. By this method the Zircaloy was submitted to hydriding process and milled in a high-energy ball mill. The powder was cold isostatically pressed and vacuum sintered. The elemental composition of the samples obtained by both ways was determined by XRF and compared to the specifications. The phase composition was determined by XRD. The microstructures resulting of both processing methods, before and after rolling were characterized using optical and scanning electron microscopy. The good results of the powder metallurgy method suggest the possibility of producing small parts, like cladding cap-ends, using near net shape sintering.
Effect of the Impurities on the Phosphoric Acid Process
Authors: Fernandes N.J. , Galvão M.A. , Araujo L.R. , Ataíde Carlos Henrique , Barrozo M.A.S.
Published: August 2012

The element phosphorus plays key role in plants metabolism. It is widely used as fertilizer. This element is usually found in insoluble forms (Ca10(PO4)6F2). The solubilization in phosphoric acid (H3PO4) is a process widely used in fertilizer industry. The impurities in the phosphate exert significant influence on recovery and productivity phosphoric process, besides affecting the quality of products. The objective of this work is to analyze the influence of some of these main impurities (iron, aluminum and magnesium) in the production process of phosphoric acid. A referential methodology (induced crystallization) of phosphoric acid production was developed. Samples of igneous phosphate concentrate contaminated with iron, aluminum and magnesium were prepared for the experiments. The reaction control parameters were similar to an industrial operation of phosphoric acid dihydrate process. Reductions in conversions, increases in viscosity and density of phosphoric acid were observed with increasing presence of these impurities. In the filtration step was found increase in resistivity of the cake with the increase of the impurities content. The iron mineral element promoted an increase in induction time of crystals nucleation.
Study of the Utilization of Chromium Plating Waste by Mechanical Activation
Authors: Izumi Marcel Tadashi , Hupalo Marcio Ferreira , Ribeiro Nathalie Carine Christoforo , de Jesus Correa Joziel , Capochi José Deodoro Trani , Cintho Osvaldo Mitsuyuki
Published: August 2012

In this study, the production of metallic chromium via metallothermic process was investigated. A chromium oxide-rich residue from chromium plating industry was characterized. Aluminothermic reduction was performed in lab-scale using an open graphite crucible. The plating residue and the aluminum powder were processed in a SPEX mill, in order to promote its effective mixing and mechanical activation. Energy dispersive X-Ray (EDX) analyses in the scanning electron microscope (SEM) have shown the presence of metallic chromium in the reaction products.
Magnetic Properties and Hardness of Nanostructured WC-Co Cemented Carbide
Authors: Manuel J.B. , Diniz M.J. , Gomes Uílame Umbelino , Silva Ariadne  de Souza , Araújo J.H.
Published: August 2012

Nacrystalline WC-10wt.%Co powders were prepared by high energy milling and liquid phase sintered. The powders with different milling time were characterized by X-ray diffraction and SEM. After sintered the WC-10wt.%Co cemented carbides exhibits ultra fine grain sizes. Coercitive field and Vickers hardness measurements on the consolided samples detected a significant increase and decrease Vickers hardness with the milling time increase in sintered samples.
Study Morphologic and Microstructural of the System CeO2-NiO Obtained by Polymeric Precursor Method
Authors: Chaves A.C. , Lira Hélio Lucena , Neves G.A. , Sales L.L.M. , Melo D.M.A. , Barros Bráulio Silva
Published: August 2012

Cerium oxide has a high potential to be apply in removing pollutants combustion powders, organic materials from waste water and in the technology of fuel cells. Nickel oxide is an attractive material due to its excellent chemical stability, and their optical, electrical and magnetic proprieties. In this work, CeO2-NiO systems on molar ratios of 1:1, 1:2 and 1:3 citric metal-acid were synthesized by using Pechinis method. The change in compositions and calcined temperature were studied by different techniques such as: XDR and SEM. It was also done a microstructural study by Rietvelds method, whose routine was designed to run in the Fullprof Suite program, and analyzed by pseudo-Voigt function. It has noticed that the molar ratio between metal-citric acid in the system CeO2-NiO 1:1, 1:2 and 1:3 has a strong influence on microstructural proprieties, crystallite size and cell micro-deformations and can be used to control these proprieties.
Influence of High Energy Milling on the Airflow Sensorproperty of the NBCa Ceramic
Authors: Caldart C. , Souza J. , Pellegrin M.Z. , Duarte Glaucea Warmeling , Rocha M.R. , Angioletto E. , Pasa A.A. , Fiori M.A.
Published: August 2012

Some materials have been applied in many surrounding conditions as sensors, electronic devices and other applications. Inexpensive and reliable temperature and flow measurement are important in many applications including, for example, environmental monitoring and control, indoor air conditioning, weather forecasting, automotive and aerospace systems. Special ceramics are an example of such materials. Neodymium-Barium-Copper is a special ceramic that has high electrical conductivity and airflow sensor characteristics. This property is influenced by high energy milling of the powder, when it is not sintered. To evaluate the influence of this type of milling it was carried out an analysis of particle size as a function of milling time. SEM images and granulometric analysis showed significant reduction of particle size with the increase of milling time. For longer times of milling the mixture of precursor powders is favored, resulting in better homogeneity of the ceramic. This is reflected in the properties of airflow sensor.
Fiber-Matrix Compatibility in LZSA Glass-Ceramic Matrix Composites
Authors: Goushegir S.M. , Guglielmi P.O. , de Oliveira Antonio Pedro Novaes , Hotza Dachamir , Janssen Rolf
Published: August 2012

Continuous fiber reinforced glass-ceramic (GC) matrix composites are potential candidates for thermomechanical applications at moderate temperatures (up to 1000°C) due to the combination of interesting properties such as high specific strength and toughness. Crack deflection into fiber-matrix interface, as well as subsequent fiber pullout and bridging are the respective toughening mechanisms. In this paper, the compatibility between LZSA glass-ceramic matrix and commercially available oxide alumina fibers (NextelTM610) is qualitatively examined. Toughening mechanisms such as crack deflection and fiber pullout are investigated by analyzing the path of Vickers-induced matrix cracks formed in the vicinity of the fibers and by investigating the crack surface of bending samples, respectively. GC matrix samples sintered and crystallized at different heat-treatment conditions have shown strong interfacial bonds between matrix and fibers, which leads to a brittle fracture without significant fiber pullout in all cases. This behavior indicates the requirement of using fiber coatings in this CMC system, to produce weak interfaces that enable toughening mechanisms to take place.
Preparation and Characterization of Composite of Polyamide 6/Nickel Ferrite
Authors: Menezes P.C.F. , de Gouveia Silva Taciana Regina , de Melo Costa Ana Cristina Figueiredo , Araújo Edcleide Maria
Published: August 2012

The research in composites attempt to predict the physico-chemical and mechanical a given mixture of materials. In this work, a composite was produced using as the polyamide 6 matrix and how the burden of nickel ferrite was incorporated as powders calcined at 1200°C and concentration of 50 wt.%. This mixture was compacted in a hydraulic press with heating and characterized by XRD, SEM and TG. XRD results showed the characteristic peaks of polyamide 6 and ferrite. SEM results showed a good dispersion of nickel ferrite loading in the matrix, the presence of larger clusters and evenly distributed load for the composite calcined at 1200 ° C. TG curves showed that the addition of loading of calcined nickel ferrite promoted an increase in thermal stability of the composite compared to pure polyamide.
Synthesis and Characterization of Chitosan/Hydroxyapatite Biocomposites Obtained by Reaction of Precipitation
Authors: Leal Rita de Cássia A. , Fook A.C.B.M. , Nascimento I.V.S.R. , Fook Marcus Vinícius Lia
Published: August 2012

There is a growing need for new biomaterials that can gain predictable and controlled tissue response, this is, that as bone graft substitutes should initiate new bone formation, after which they should get reabsorbed and replaced by bone tissue. This combination aims to improve the mechanical properties, degradation rates and absorption rates of biocompatibility and biodegradability. The aim of this study was to propose a synthetic route in which the HA was obtained by reaction of precipitation directly on evaluating the influence of chitosan biopolymer in the middle of precipitation in the characteristics of hydroxyapatite obtained. XRD analysis revealed the presence of HA phase with low crystallinity. In the FTIR analysis identified the characteristic bands of hydroxyapatite, as well as bands that characterize an interaction between chitosan and hydroxyapatite, as the band around 1050cm-1. SEM analysis of the biocomposites chitosan/HA, showed a dispersion of HA particles in chitosan, revealing a homogenous material and microporous.
Production of Borosilicate Glasses from Residues of Ornamental Rocks
Authors: Blazutti Marçal Rubens Lincoln Santana , Prado da Silva Marcelo Henrique , de Sousa Lima Eduardo , Louro Luis Henrique Leme
Published: August 2012

In this work, glasses with compositions, close to commercial borosilicate glasses, were developed. The main raw materials were residues of ornamental rock industries ( marbles and granites ). Beach sand was used in order to enrich the compositions with silica. Also, boron oxide was added to reach borosilicate glasses compositions. The obtained glasses were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), and hydrolytic resistance. The measured properties were compared to those of commercial glasses, available in the market, from two different brands. XRD results confirmed amorphous patterns of the produced glasses. The other tests revealed an excellent agreement between the obtained values and those from commercial glasses. Therefore, this study showed the possibility of using ornamental rocks residues as primary sources to produce borosilicate glasses. In addition, it became clear that an economic value could be aggregated to the residues, which otherwise would be discharged into nature causing pollution.
Evaluation of the Thickness and Permeability in Asymmetric Membranes of TiO2 Supported on Alumina
Authors: de Almeida Ester Pires , de Freitas Normanda Lino , Kiminami Ruth Herta Goldsmith Aliaga , Lira Hélio Lucena , de Melo Costa Ana Cristina Figueiredo
Published: August 2012

The aim of this study is to evaluate the thickness and permeability of the membranes of TiO2 supported on Al2O3. The TiO2 samples were prepared by combustion reaction method using monohydrated citric acid, aniline and urea as fuel. It was prepared three samples with different morphological characteristics. The membranes were prepared by dip coating, and characterized by scanning electron microscopy (SEM), permeate flux and turbidity in laboratory test. The membrane obtained with urea presented layer formed at 16 µm of thickness. For membrane obtained with powder from citric acid and aniline do not presented layer formation. The membrane obtained with samples synthesized urea showed: higher permeated flux (185.46 kg/ h.m ²), higher particle rejection (97%) and lower turbidity (0.99 NTU) with contaminated water. The membrane obtained with powders from citric acid and aniline showed: permeated flux of 128.61 and 138.41 kg/h.m², rejection of 96 and 95% and turbidity of 1.33 and 1.13 NTU, respectively.
Development of Ultrafiltration Tubular Ceramic Membrane Using in their Composition Granite Residue
Authors: de Oliveira Lima Rosa do Carmo , Oliveira Guimarães Iliana , Lira Hélio Lucena , Neves Gelmires Araújo , da Silva Carla Dantas , da Silva Farias Mirele Costa
Published: August 2012

The membrane separation processes present several advantages in relation to the traditional process, such as high selectivity, easy operation, good results in the effluent treatments, low energy consumption, small number of processing step, can be applied to thermo sensible substances, easy to combine with other process and scale up, great efficiency in the final product (PORTER, 1990; CAMPOS, 2000). The materials employed in the membrane preparation can be metals, ceramic, polymer or composites.
Manufacture and Characterization of Alumina Ceramic Foams for Porous Burners
Authors: Herrera Ana María , Moreno Verônica , Oliveira Jr. Amir A.M. , Hotza Dachamir , Álvarez Oscar Alberto , Escobar Jairo Arturo
Published: August 2012

Hazardous byproducts emissions such as nitrogen oxides (NOx) and carbon monoxide (CO) might be controlled by the use of radiant porous burners. Those heaters require a solid porous matrix where combustion reaction takes place, reason why the heat transfer is much more efficient. This project was based on a rheology study of an alumina slurry, where parameters like viscosity and tixotropy were the guide to select the appropriate formulation to be used in the fabrication of ceramic foams by the replica method. Low strength samples were produced after the first thermal treatment, explained by the absence of a plasticizer when using PVA as a binder. Incomplete sintered foams were obtained due to an insufficient soak time.
Enamel Development and Application on the Pottery of Icoaraci
Authors: da Cruz Reis Andre Wilson , Cruz Martelli Marlice , de Freitas Neves Roberto
Published: August 2012

The development of technology for the application of enamels on pieces of red pottery, in the handicraft sector, is an alternative to improve the quality of the ceramic body forming a waterproof layer that serves as a protection when used for foods and also to add a decorative effect and increase commercial value. This work develops an enameling technique in the production conditions of the artisans in the village of Icoaraci-PA/Brazil. The characterization of raw materials was performed by X-ray fluorescence, X-ray diffraction, particle size analysis, Thermogravimetric and Differential Thermal Analysis. Steps for enamel preparation using commercial transparent frit and bottle glass, and the technique for applying the glaze and firing are presented. The results for the test pieces were very good with the application of transparent frit fired at 900 ° C for 3 hours.
Influence of Substrate Temperature in the Morphology and Microstructure of YSZ Films Obtained on LSM Porous Substrate via Spray Pyrolysis
Authors: Falcade Tiago , de Oliveira Giselle Barbosa , Tarragó Diego Pereira , de Sousa Vânia Caldas , Malfatti Célia de Fraga
Published: August 2012

Many studies have been reported in the literature related to YSZ films deposited on dense substrate or applied directly on the SOFC anode. However, there are not a lot of studies about the YSZ deposition on the cathode. The present work aims to obtain yttria-stabilized zirconia (YSZ), using the spray pyrolysis technique, for their application as electrolyte in solid oxide fuel cells (SOFC). The films were obtained from a precursor solution containing zirconium and yttrium salts, dissolved in ethanol and propylene glycol (1:1), this solution was sprayed onto a heated LSM porous substrate. The substrate temperature was varied in order to obtain dense and homogeneous films. After deposition, the films were heat treated, aiming to crystallize and stabilize the zirconia cubic phase. The films were characterized by Scanning Electron Microscopy (SEM), thermal analysis, X-ray diffraction and Fourier transform Infrared Spectroscopy (FT-IR).
Evaluation of Compaction Behaviour of Spray-Dried Alumina by Hg Porosimetry and SEM
Authors: Santos A.A. , Cosentino I.C. , Genova Luis Antonio
Published: August 2012

The powder compaction process is the most widely used forming technique for shaping ceramic products, since traditional ceramic as floors until advanced ceramics for technical applications. This process is characterized by high productivity but it has a serious problem, namely the density gradient originated during the die cavity filling and the subsequent compaction operation[. Therefore, the process requires a high control of all parameters involved in order to guarantee to obtain samples with high homogeneity of the green density, which ensures a sintered body of high quality and low population of microstructural defects. Thus, it is extremely important to understand the variable that controls the compaction mechanisms and interfere in the homogeneity of the green density along the compacted body.
Characterization of SOFCS: A Crystallographic Analysis and First Steps towards an Impedance Spectroscopy Approach
Authors: Ávila A. , Poveda J. , Gómez D. , Hotza D. , Escobar J.
Published: August 2012

Solid oxide fuel cells (SOFCs) have emerged as an efficient way to transform chemical energy into electrical energy. However, a major disadvantage of this technology is related to the high temperatures required for SOFC operation. In this way, new materials are necessary to maintain the electrical properties of the cell at intermediate temperatures. Based on these ideas, it is necessary to study both the structural variation of the cells components at different temperatures and their electrochemical behavior. In this work, a crystallographic characterization is presented, which was performed in a commercial SOFC cell using X-ray diffraction (XRD). An equivalent linear electrical model to predict SOFC losses is developed as well. Keywords: Solid oxide fuel cells (SOFCs); AC impedance; Electrochemical impedance spectroscopy (EIS); Equivalent circuit models.
Synthesis of Mulita Nanometric from Delaminated Bentonite-Study of the Percentage of Stages and Size of Crystal
Authors: Gomes Josileido , Cartaxo Juliana Melo , Menezes Romualdo Rodrigues , Neves Gelmires Araújo , Brasileiro Maria Isabel , de Lima Santana Lisiane Navarro
Published: August 2012

A wide variety of synthesis methods have been proposed for obtaining mullite, however, some techniques produce powders with heterogeneous morphology and a large amount of glassy phase, forming large clusters making it difficult to obtain nanopowders. The microwave synthesis offers advantages over conventional methods, the heating is rapid and uniform, avoiding an undesirable grain growth. The aim of this work was the synthesis of nanoscale mullites powders from delaminated bentonites. For the process of delamination samples were initially treated, then rehydrated, frozen and deagglomeration in ball mill and subsequently subjected to centrifugation, in order to produce a nanosized precursor for the synthesis of mullite. The powders obtained after peeling were characterized chemical and mineralogical. The synthesis of mullite was performed in a microwave oven and the powders were characterized by XRD and SEM. The results showed that the delamination of the bentonite and microwave synthesis were essential in obtaining nanopowders mullite.
Alumina Foam Coated with Strontium Oxide as a Heterogeneous Catalyst
Authors: Bassetti F.B. , Innocentini Murilo Daniel de Mello , Pereira Gilberto J. , Ortega Fernando dos Santos
Published: August 2012

The most common method to produce biodiesel is the transesterification of oils in the presence of methanol and a catalyst. Catalysts may be either homogeneous or heterogeneous, whereas the heterogeneous consume fewer resources, energy and are reusable, being considered an environmentally attractive approach. This research presents the production of a heterogeneous catalysis system for biodiesel synthesis, consisting of alumina foam with a thin coating of SrO. The support, obtained by direct foaming of suspensions, presented approximately 90% vol. of highly connected pores. The SrO film was obtained by soaking the ceramic foam into either a Pechini resin with SrO precursors or an aqueous solution of strontium nitrate, followed by heating to 1400°C for 2 hours. The density and permeability of samples were evaluated and microstructure was characterized by EDS and SEM. The results show that the use of ceramic foams as catalyst support is feasible using the proposed route.
Study of the Sintering of Mixtures Al2O3-Nb2O5 and Y2O3-Nb2O5
Authors: Cabral Ricardo F. , Prado da Silva Marcelo Henrique , de Campos Jose B. , Lima Eduardo Sousa
Published: August 2012

Al2O3-Nb2O5 has been widely explored as one of the most used material for sintering mixing in the literature, due to its excellent hardness properties, used in armor. In this study, Al2O3-Nb2O5 and Y2O3-Nb2O5 powders were prepared, with 50% in mole fraction of each oxide. The mixtures were subjected to high energy milling in an eccentric ball mill for 3 h, dried and sieved in a sieve vibrator. The green bodies were compacted at 70 MPa and sintered from 1250 to 1650 °C for 3 h, at 100 °C steps. The materials were characterized by quantitative X-Ray diffraction (XRD) using Rietveld method and by mass loss. The Al2O3-Nb2O5 mixtures experienced a weight loss of 84% at sintering temperatures of 1550 and 1650 °C.
Microstructure and Electrochemical Properties of a LaMgAlMnCoNi Based Alloy for Ni/MH Batteries
Authors: Ferreira Eliner Affonso , Serra J.M. , Casini Julio César Serafim , Takiishi Hidetoshi , de Faria Jr. Rubens Nunes
Published: August 2012

The microstructure and electrochemical properties of a La0.7Mg0.3Al0.3Mn0.4Co0.5Ni3.8 hydrogen storage alloy have been studied. The anode was prepared using a mixture of the ingot alloy in the as-cast state with carbon black and polytetrafluoroethylene (PTFE) as a binder. A Ni (OH)2 electrode was used as the cathode of the square-type test cell. A separator was used together with a 6M KOH electrolyte. Microstructure and phase composition of the alloy have been investigated using inductively coupled plasma atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD). A niobium-containing alloy has also been included for a comparison.
Life Cycle Assessment of Ceramic Bricks
Authors: Gomes Jerônimo Moraes , Salgado Ana Luiza Folchini , Hotza Dachamir
Published: August 2012

Ceramic bricks are one of the most widely used materials in both commercial and residential buildings. Ceramic bricks play a relevant role in the Brazilian economy. The basic input material for this industry is red clay. As environmental problems increase, the need for environment-friendly building design increases. To achieve this, architects and engineers need reliable data on the environmental impacts of various building materials, including ceramic bricks. In this paper a comparative Life Cycle Assessment between two ceramic brick production units in Santa Catarina State, Brazil, has been carried in a comparative approach. Key impact categories, including fossil fuel use, global warming, ozone depletion, ecotoxicity, and human toxicity were assessed. The analysis has shown a particular relevance of the respiratory effects in both systems and the critical point has been found in the fuel used in the furnace for firing the bricks which are responsible, during the ring process, for the relevant CO2 emissions.
Characterization of the City of Red Clay Apodi-RN
Authors: Monteiro Flanelson M. , Machado Tércio G. , Sousa José , Harima Eiji , Valcacer Samara M. , Nascimento Rubens M.
Published: August 2012

Ceramic products made from red clay to move the economy of Rio Grande do Norte. Among the most common ones are outstanding bricks, tiles and slabs in different sizes and shapes. In perspective to seek products with good quality in the ceramic industry, the characterization of the raw material is essential for obtaining an excite end product. The municipality of Apodi located in the Upper West Rio Grande do Norte has the ceramic industry as a sector of great economic importance in the site. However the absence of technology for characterization of the clays found in the region is the major problem for local entrepreneurs. The objective this study is to characterize the red clay one of the ceramics used by the municipality of Apodi-RN. The procedure will be done through the testing of Plasticity, Liquidity, linear shrinkage, absorption water, porosity, XRD and EDX.
Influence of Bentonite Clay in the Formation of Polypropylene / Clay Nanocomposites
Authors: da Cunha Bartira Brandão , Damião Rodolfo Ferreira , Agrawal Pankaj , Araújo Edcleide Maria , de Mélo Tomás Jefférson Alves
Published: August 2012

Based on recent studies this research aims to continue the studies on nanocomposites obtained by blending polypropylene (polymer matrix) and bentonite clays of Paraíba, with emphasis on issues related to the surface modification of clays (charges), with the aim of stimulating the compatibility between the inorganic and organic components, since after the modification with organic surfactants, is easier for the clay to interact with the polymer. First was evaluated the effect of the concentration of clay (0.5, 3 and 5 phr - parts per hundred resin) on the properties of polypropylene and then a compatibilizer was used in order to further increase the properties of the composites. The results showed a very significant increase in both mechanical and morphological properties of the material as a function of clay content in the polymer matrix and dispersed systems with compatibilizer showed even higher properties, such as a significant gain in impact strength of polypropylene without loss in modulus of elasticity.
Performance of Nanostructured Diamond Composites in Wear Tests
Authors: Skury Ana Lúcia Diegues , Monteiro Sérgio Neves , de Azevedo Marcia G. , Motta Laís B. , Bobrovinitchii Guerold Sergueevitch
Published: August 2012

Diamond-Si nanostructured composites were obtained by cyclic high pressure and high temperature sintering with different processing conditions to examine the dominant microstructural factors and the abrasive wear resistance. The microstructure of the composites was characterized by scanning electron microscopy. The abrasive wear behavior of the composites was evaluated by weight loss in abrasion tests. It was found that improved nanostructured composite properties and denser structures were obtained for sintering performed with more than one cycle of pressure and temperature.
Use of Niobium Oxide as a Binder in the Production of Diamond Nanostructured Composites
Authors: Skury Ana Lúcia Diegues , Bobrovinitchii Guerold Sergueevitch , de Azevedo Marcia G. , Monteiro Sérgio Neves
Published: August 2012

The sintering of nanodiamond powders is of interest for both applied engineering of tool materials and fundamental materials science of nanodisperse covalent-type ceramic materials. It is a accept as a general notion that the driving force for sintering of monophase particles is determined by the level of the surface energy. In the case of diamond nanopowder, this level must be significantly higher which makes sintering a difficult process. This difficulty of sintering is connected with the low diffusive mobility of carbon causing the formation of a graphite structure onto surface of the diamond crystals. From this point of view the use of niobium oxide as a binder could be a solution. In an attempt to inhibit the diamonds graphitization process, Nb2O5 and small amounts of amorphous carbon were introduced in the reaction zone. Sintering process was conducted at 6.0 GPa of pressure and 1100-1400oC for a processing time of 30 seconds. At the end of the process, the samples were cleaned, and prepared to be characterized by X-ray diffraction, scanning electron microscopy, density and porosity. From these results it was proposed a densification mechanism based on the consolidation of the particle by diffusion and coalescence of clusters.
Effect of Glassy Phase Additions to Zirconia on its Mechanical Properties
Authors: de Oliveira Vera Lúcia Praxedes , Prado da Silva Marcelo Henrique , de Sousa Lima Eduardo , dos Santos Claudinei , Louro Luis Henrique Leme
Published: August 2012

Glasses with two different compositions were added to yttria-stabilized zirconia TZP powder: a CAS glass and a bioactive glass. These additions allowed liquid phase sintering to occur at temperature as low as 1300 °C. The concentrations of each glass additions were of 1, 3, and 5 wt%. The prepared compositions were uniaxially pressed at 50 MPa and sintered at 1300oC for 2 hours. The sintered samples were characterized for their mechanical properties, by measuring four-point bending mechanical strength, Vickers microhardnesses, and fracture toughness ( KIc ). Vickers microhardness measured values ranged from 10 to 12 GPa, while fracture toughness, from 3.8 to 4.4 MPa.m1/2. The flexural mechanical strength was situated between 302 and 408 MPa. The achieved mechanical properties, from sintered samples were possible due to glassy phase additions. These properties, associated to biocompatibility, enable such materials to be used in different applications, including bioceramics.
Sintering of Ni-Zn Ferrite by Microwave Energy
Authors: Diniz Verônica C.S. , Vieira Débora A. , Kiminami Ruth Herta Goldsmith Aliaga , Cornejo Daniel , de Melo Costa Ana Cristina Figueiredo
Published: August 2012

This paper proposes to assess the sintering of Ni-Zn ferrites synthesized by combustion reaction in advance to procure materials for applications as soft magnetic devices. The samples used for sintering have different morphological characteristics and were previously synthesized by microwave energy. The samples were uniaxially pressed and sintered in a microwave oven at 1200°C/2h with a heating rate of 5°C/min, and characterized by XRD, SEM and magnetic measurements. The results show that for all samples have the formation of Ni-Zn phase and traces hematite as secondary phase. The resulting microstructure after sintering was different and was influenced by previous morphological characteristics of the synthesized samples. As for the magnetic parameters, all samples were characteristic of soft magnetic material with saturation magnetization between 57 and 62 emu.g-1, indicating are promising materials for the fabrication of soft magnetic devices.
Use of Ash from the Incineration of Elephant Grass (Pennisetum purpureums shaum) into Clayey Ceramic
Authors: Silva A.M.F.D. , Lovise L.S. , Monteiro Sérgio Neves , Vieira Carlos Maurício Fontes
Published: August 2012

Ashes generated in industrial processes are usually discarded and contribute to environmental pollution. Large scale incorporation into clayey ceramic products for civil construction, such as bricks and tiles, could be a permanent solution. Based on this rationale, this works has as its objective to characterize an ash waste from the incineration of elephant grass and to evaluate its incorporation into a clay to produce red ceramic. The waste was submitted to mineralogical and chemical characterization. Compositions were prepared with incorporation of the waste in amounts of up to 20 wt.% into the clay. Specimens were prepared by extrusion and fired in a laboratory furnace at 850°C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural strength. The results showed that the waste is mainly composed of quartz and calcium compounds that sensibly reduce the linear shrinkage and does not change the other properties of the ceramic.
Hydrodynamics of the Aluminium Barbotage Process Conducted in a Continuous Reactor
Authors: Saternus Mariola
Published: August 2012

Today aluminium obtained from ores (primary) and from scrap (secondary) need to be refined. During this process harmful impurities such as hydrogen, sodium, lithium, oxides, borides or carbides can be removed. There are many different ways of aluminium refining process. The most popular seem to be barbotage that means blowing through aluminium many tiny gas bubbles of refining gas. Reactors applying this methods have been working all over the word. They are of different types: bath and continuous, using ceramic porous plugs, special kinds of nozzles or rotary impeller for generating small gas bubbles. At present reactors for continuous refining have become the most popular. In Poland typical representative of such reactors is URC-7000 reactor. The phenomena occurring during this process are rather complicated. Therefore to know them better the modelling research is applied, especially physical modelling. The paper presents the results of such a research. The tests were carried out in the test stand for modelling the babotage process in the URC-7000 reactor. The different modelling agents were tested (water, glycerin and mixture of water and glycerine). The density and viscosity of water and glycerin mixture were determined. Modelling tests were conducted for four different flow rates of refining gas: 6, 10, 15 and 20 dm3/min. Results were registered by digital camera. Pictures for different modelling agents were juxtaposed and discussed.
Effect of a High-Temperature Hydrogen Treatment on a Microstructure and Surface Fracture in Titanium Ti-6Al-4V Alloy
Authors: Sozańska Maria
Published: August 2012

Influence of hydrogen on the structure of titanium alloys is a complex phenomenon, depending on the circumstances, may be negative or positive [1,2]. The presence of hydrogen in titanium alloys usually results in degradation of their microstructure and properties, as well promote some undesirable effects such as hydrogen corrosion and hydrogen embrittlement [3]. Positive nature of the effects of hydrogen on the properties of titanium alloys is manifested in the high temperature hydrogen treatment (HTM - Hydrogen Treatment of Materials), where hydrogen is temporary alloying component [4-9]. This is possible because of the high values of diffusion coefficients can be easily introduced into the titanium and it just as easily removed. Titanium and its alloys show the absorbability of almost 60 at. % of hydrogen at 600°C. The limit hydrogen of solubility in Tiα is very low and does not exceed 0.05 at. % at room temperature. The limit hydrogen of solubility in Tiβ is much higher and its maximum value is 48 at. %. Since the beginning of the titanium industry, a great deal of attention has been paid to control the hydrogen content at titanium products – above 0.2 ppm. The paper presents the results of the possibilities of hydrogen using as a temporary alloying element in Ti-6Al-4V alloy. Treatment of hydrogen alloy consisted of three stages: hydrogenation in hydrogen gas atmosphere at 650 °C, a cyclic hydrogen-treatment (3 cycles 650 °C to 250 °C) and a dehydrogenation in vacuum (550 °C). It was shown that hydrogen affects appreciably changes the microstructure of surface layer of the tested titanium alloy. The aim of this study is thus to determine the effect of hydrogen on the two-phase microstructure, hardness, and surface fracture of the titanium alloy Ti-6Al-4V due to high-temperature hydrogen treatment.
Inducible IL-33 Expression by Mast Cells Is Regulated by a Calcium-Dependent Pathway
Authors: Hsu Chia-Lin , Bryce Paul J.
Published: August 2012

IL-33 is an IL-1 family cytokine that displays dual functions: a cytokine via its receptor, T1/ST2, or a chromatin-binding factor within the nucleus. Functionally, it promotes Th2-associated immunity by enhancing the activation and survival of several cell types. However, the pathways regulating IL-33 expression are still unclear. Although several cells display constitutive expression of IL-33, we showed previously that mast cells expressed low levels of IL-33 constitutively but that IL-33 was induced upon IgE-mediated activation. This was mediated via a calcium-dependent mechanism. In this study, we define the pathway through which this inducible IL-33 is regulated. Importantly, this pathway does not alter expression in cells with high constitutive IL-33 expression, such as epithelial cells or fibroblasts. Our data show that, upstream of calcium, inhibition of PI3K and Sphk activity decreases inducible IL-33 expression to IgE/Ag activation. Additionally, expression of Sphk1 short hairpin RNA prevents upregulation of IL-33 expression. Downstream of calcium, NFAT activity is necessary and sufficient for inducible IL-33 expression. We also demonstrate calcium-dependent transcription from two regions of the IL-33 gene that contain putative NFAT-binding sites, one upstream of exon 1 and one upstream of the start site. Interestingly, we show that blocking other calcium pathways, including inositol triphosphate receptor, or NF-κB inhibits IgE-driven IL-1β, another IL-1 family cytokine, but it has no influence on inducible IL-33 expression. In summary, our data demonstrate cell-specific differences in the regulation of IL-33 expression and define a pathway critical for the expression of inducible IL-33 by mast cells upon their activation.
The Molecular Signature of Tissue Resident Memory CD8 T Cells Isolated from the Brain
Authors: Wakim Linda M. , Woodward-Davis Amanda , Liu Ruijie , Hu Yifang , Villadangos Jose , Smyth Gordon , Bevan Michael J.
Published: August 2012

Tissue resident memory (Trm) CD8 T cells represent a newly described memory T cell population. We have previously characterized a population of Trm cells that persists within the brain after acute virus infection. Although capable of providing marked protection against a subsequent local challenge, brain Trm cells do not undergo recall expansion after dissociation from the tissue. Furthermore, these Trm cells do not depend on the same survival factors as the circulating memory T cell pool as assessed either in vivo or in vitro. To gain greater insight into this population of cells, we compared the gene expression profiles of Trm cells isolated from the brain with those of circulating memory T cells isolated from the spleen after an acute virus infection. Trm cells displayed altered expression of genes involved in chemotaxis, expressed a distinct set of transcription factors, and overexpressed several inhibitory receptors. Cumulatively, these data indicate that Trm cells are a distinct memory T cell population disconnected from the circulating memory T cell pool and display a unique molecular signature that likely results in optimal survival and function within their local environment.
Is journaling empowering? Students’ perceptions of their reflective writing experience
Authors: Harris M
Published: August 2012

South African health care organisations are faced by enormous challenges. Responsive measures must include

employing nurse practitioners who can think critically and creatively and who can make appropriate decisions that

do not necessarily fit into theory learned within a formal educational system.

Opsomming

’n Opvoedkundige program vir Suid-Afrikaanse verpleegkundiges van verskillende kulture, gebaseer op ’n model vir kritiese ondersoek van taakverrigting (Van Aswegen, 1998), het tot hierdie navorsing aanleiding gegee.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Editorial Comments/ Redaksionele Kommentaar
Authors: Stuart A D
Published: August 2012

This edition of Health SA Gesondheid reflects the dichotomous, reciprocal and holistic natures of the two disciplines which are well represented in this Journal namely Psychology and Nursing Science.

Opsomming

Hierdie uitgawe van Heath SA Gesondheid reflekteer die tweeledigheid, resiprokaliteit en holisme van twee dissiplines wat sterk in die joernaal verteenwoordig word, naamlik Sielkunde en Verpleegkunde.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
The impact of organisational culture on the adaptation of newly employed nurses to the work environment
Authors: Khoza L B
Published: August 2012

Usually newly employed nurses find adjusting to a work setting a challenging experience.

Opsomming

Gewoonlik is die aanpassing by ‘n nuwe werksomgewing vir pasaangestelde verpleegkundiges ‘n groot uitdaging.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Service-learning in nursing: integrating student learning and community- based service experience through reflective practice
Authors: Julie Hester , Daniels Priscilla , Adonis Tracey-Ann
Published: August 2012

Domestic violence is a pervasive problem in South Africa.

Opsomming

Huishoudelike geweld is ’n wydverspreide probleem in Suid-Afrika.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Prescribing patterns of methylphenidate in a South African patient population who are members of a private medical aid
Authors: Truter Ilse , Van W Kotze Theunis J
Published: August 2012

Methylphenidate is primarily used for attention deficit hyperactivity disorder (ADHD) in children.

Opsomming

Metielfenidaat word hoofsaaklik vir aandag-gebrek-hiperaktiwiteitsindroom in kinders gebruik.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Neurological aspects of stuttering: summary overview of scientific findings
Authors: Willemse Naudine , Viljoen Margaretha , Govender Catherine
Published: August 2012

The aim of this article is to provide a summary overview of some of the more important scientific evidence of neurological differences between stutterers and non-stutterers.

Opsomming

Die doel van hierdie artikel is om ‘n opsommende oorsig te bied van die belangrikste wetenskaplike bewyse vir neurologiese verskille tussen mense wat hakkel en mense wat nie hakkel nie.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Obesity as an inflammatory condition
Authors: Slabbert Sonja , De Ridder Hans J , Underhay Colette , Kruger Salomé
Published: August 2012

The prevalence of obesity has increased dramatically in the past decade.

Opsomming

Die voorkoms van obesiteit het oor die afgelope dekade dramaties gestyg en daarmee saam die voorspelling van ‘n toename in morbiditeit sowel as mortaliteit as gevolg van obesiteit-verwante siektetoestande

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
The professional nurse’s experience of the dying process of the terminal Aids patient
Authors: Bester Petra , Du Plessis Engela , Greeff Minrie
Published: August 2012

The increase in HIV/AIDS raises international concern. Statistics indicate that South Africa has the fastest increasing

HIV-infection rate in the world.

Opsomming

Die toename in MIV/VIGS wek internasionale kommer. Statistiek toon dat Suid-Afrika die snelstygendste MIVbesmettingskoers ter wêreld het.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Editorial Comments/ Redaksionele Kommentaar
Authors: Poggenpoel Marie
Published: August 2012

This spring edition of Health SA Gesondheid is as lively and colourful as the green leaves and blossoms that signals new life in nature.

Opsomming

Hierdie lente uitgawe van Health SA Gesondheid is net so lewendig en kleurvol soos die groen blare en bloeisels wat die nuwe lewe in die natuur aankondig.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Empowerment of parents in the neonatal intensive care unit by neonatal nurses
Authors: Herbst Adene , Maree Carin
Published: August 2012

Parents of infants who are admitted to the neonatal intensive care unit (NICU) need to be empowered to improve bonding, attachment and care-giving skills.

Opsomming

Ouers van babas wat in die neonatale intensiewesorgeenheid (NISE) opgeneem word, moet bemagtig word met dieoog op bevordering van binding, ’n hegte band met die babas en versorgingsvaardighede.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
The surgical management and speech and swallowing rehabilitation of patients with advanced tongue cancer in South Africa
Authors: Engelbrecht Leanie , Van der Merwe Anita , Pretorius Jan P
Published: August 2012

Advanced tongue cancer may have a devastating effect on a person’s ability to speak and to swallow. Very little is known about the surgical management and speech and swallowing rehabilitation of persons with advanced tongue cancer in South Africa.

Opsomming

Gevorderde tongkanker het ‘n geweldige impak op ‘n persoon se vermoë om te praat en te sluk. Baie min inligting is bekend oor die chirurgiese behandeling en spraak- en slukrehabilitasie van persone met gevorderde tongkanker in Suid-Afrika.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Public perception of community pharmacists in South Africa: a preliminary study
Authors: Bornman Suzanne , Truter Ilse , Venter Daniel JL
Published: August 2012

This survey forms part of a study undertaken to identify and quantify the community pharmacist’s involvement in the use of non-prescription/over-the-counter (OTC) medicine/self-medication in community pharmacies throughout South Africa.

Opsomming

Hierdie opname vorm deel van ‘n studie wat onderneem word om die gemeenskapsapteker se betrokkenheid in die gebruik van nie-voorskrif/oor-die-toonbank medikasie/ selfmedikasie in gemeenskapsapteke in Suid Afrika te identifiseer en te kwantifiseer.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Editorial Comments/ Redaksionele Kommentaar
Authors: Nolte A G W
Published: August 2012

This volume of our journal brings you a bouquet of articles which embody the spirit of this publication.

Opsomming

Hierdie uitgawe van ons tydskrif bied aan u ‘n verskeidenheid artikels wat die gees van die publikasie omvat.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.
Factors impacting on contraceptive use among youth in northern Tshwane: Part 2
Authors: Maja T M M
Published: August 2012

Young people are vulnerable to risky behaviors that cause major health problems such as sexual behaviour resulting in early, unplanned pregnancy and sexually transmitted diseases (STDs) including human immunodeficiency virus (HIV).

ABSTRAK

Die jeug is besonder kwesbaar as gevolg van riskante gedrag wat groot gesondheidsprobleme soos seksuele gedrag veroorsaak wat tot seksueel oordraagbare siektes en VIGS mag lei. Hierdie studie is gedoen om die faktore wat ’n impak het op die gebruik van voorbehoedmiddels en dienste hiervoor vir jeugdiges in Noord-Tshwane te identifiseer en te beskryf.
The cultural beliefs of the Vhavenda on the causes and transmission of sexually transmitted infections
Authors: Mulaudzi Fhumulani Mavis
Published: August 2012

Cultural and ethnic identity and folk beliefs play a decisive role in perceptions, attitudes and practices regarding health care and illness.

Opsomming

Kulturele en etniese identiteit en volksgelowe speel ’n deurslaggewende rol in die persepsies, houdings en gebruike ten opsigte van gesondheidsorg en siekte.

*Please note: This is a reduced version of the abstract. Please refer to PDF for full text.