bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Construction Technology of Fixation Stent Installing Comb Expansion Joint
Authors: Liu Feng , Li Su Ping , Chen Yun Quan , Hou Kang
Published: June 2015

The hot-rolling-whole-molded and comb-type-designed bridge expansion devices are widely used in the urban and highway bridges, owning the characteristics of large expansion allowance and small burial depth. Whereas using traditional craft to install comb-type expansion joint, such phenomenon like settlement, water seepage, bumping and noise in driving would happen with slow construction. Through continuous improvement for many years, Jinan Urban Construction Group has developed a full construction technology of installing comb expansion joint based on fixation stent by using tailor-made location frame to integrally move the anchor bolt group into the groove for firm weld with embedded steel, matching with moving lifting tool. Through this construction technology, the efficiency of construction is improved, the construction period is shortened, and the smoothness of asphalt after installing comb plate would meet the design requirements, also such quality defects like bumping and abnormal sound would be precluded. hot-rolling-whole-molded and comb-type-designed bridge expansion devices
Static Model Experiment Study on a Concrete-Filled Steel Tubular Arch Bridge
Authors: Li Yong , Wang Yan Xu
Published: June 2015

It is well known that a lot of concrete filled steel tubular (CFST) arch bridges were built in China. Thus it became a main bridge type. Its architectural design shows much novelty, while the structural design is always conducted based on the finite element (FE) model analysis. Meanwhile there is no professional code for design and construction of this type of bridge. To overcome these disadvantages, scaled model tests are preferable to evaluate the mechanical behavior and provide guidelines for design and construction of prototype bridges. In this paper, an irregular CFST arch bridge as the prototype was introduced and a 1/16 scaled bridge model was designed and constructed according to the similarity theory. The experimental study on the scaled model was aimed to simulate the construction stages and mechanical behavior under moving loads. The test results are used to make comparison with the construction monitoring and bearing-capacity load test of the prototype. The analysis shows that the experimental results of the scaled model are close to the measured results of the prototype. The scaled model test was proved to be valuable for the pre-camber setup of the arch rib and the tension optimization of the suspenders and for the operation safety.
A New Technique for Construction of Limestone Cave
Authors: Jin Bao , Zhang Hong Jun , Zhang Jian Yang
Published: June 2015

A cave is formed when surface water and groundwater effect on soluble rocks through chemical and mechanical damage. That is called karst phenomenon. It will affect the stability and stress distribution of the surrounding rock. Part of the tunnel construction process will affect the stress distribution of the surrounding rock greatly. Some caves are unavoidable, which could make structures insecurity and instability. At the same time, the construction process will become complicated. Caves will increase the risk and uncertainty of the whole project as well. Therefore, the development of scientific and efficient measures to ensure the quality and safety of the construction project becomes extremely important. In this paper several safety precautions would be introduced based on the specific case of tunnel construction. And experience will be given in order to benefit the construction of similar problems.
Synthesis and Sulfating of the ZrO2 for Obtaining of a Catalyst in Order to Future Use in Esterification for Biodiesel Production
Authors: Silva Francisco Nilson , Dantas J. , Silva A.S. , Pallone E.M.J.A. , Costa A.C.F.M.
Published: June 2015

This work aims to synthesize ZrO2by the combustion reaction method and its sulfating for future use as a catalyst in esterification of the cottonseed oil. The synthesized sample was produced in batches of 15g, using as precursor the zirconium IV n-propoxide and urea as fuel. The sulfating occurred with an ion content of SO4-2with 30% in relation to the mass of ZrO2. The samples were characterized by XRD, SEM and particle size distribution. The results revealed the formation of the monoclinic majority phase with traces of the orthorhombic phase referring to the synthesized sample, and a transformation of the orthorhombic phase to the tetragonal phase when sulfated. The morphology have shown the formation of homogeneous and spherical agglomerates, with a mean particle size of 24.34nm. The presence of traces of the tetragonal phase in the XRD of the SO42-/ZrO2was a great indicator for future use in the esterification reaction to obtain biodiesel, because this type of phase after sulfating becomes very promising for the ester obtaining.
Synthesis and Characterization of Pseudoboehmite and Gamma-Alumina
Authors: Munhoz Antonio Hortêncio , de Paiva H. , de Miranda Leila Figueiredo , de Oliveira E.C. , Andrades Raphael Cons , Neto Abner Cabral
Published: June 2015

Pseudoboehmite (PB) were synthesized through the sol-gel process, using aluminum nitrate as precursor. The pH adjustment of the precursor solution was made by using ammonium carbonate. After the precipitation, the material was dried at 70°C before characterization. The pseudoboehmite obtained were characterized by x-ray diffraction, scanning electron microscopy and afterwards by thermal analysis (DTA and TG). The pseudoboehmite was also calcined at 500oC to obtain gamma-alumina. The specific surface area measurements through the BET process and the desorption-absorption of nitrogen as well the t plot in order to evaluate the pore volume of the calcined samples was realized. Finally, the results showed that the synthesized pseudoboehmite can be used to produce high specific surface material with a crystal structure of gamma-Al2O3(around 324m2/g).
Chemical Synthesis and Sintering Behaviour of Ca3Al206 Obtained by Polymeric Precursor Method
Authors: Veiga Faili Cintia Tomsen , Gaier Marciel , Ratmann Cristiane Raubach , Moreira Mário Lúcio , Jurado José , Longo Elson , Sousa Vânia Caldas , Cava Sergio
Published: June 2015

Tricalcium aluminate (C3A) are used for different applications such as thermal insulation, cement, refractory concrete as binders or binders. The aim of this work is to study the synthesis and sintering behaviour of C3A samples. The chemical synthesis was performed by means of polymeric precursor method from metalic nitrates dissolved in ethylene glycol and citric acid forming a polymeric resin. The evolution of the crystalline phases was accomplished by X ray Diffraction (XRD). Thermogravimetric (TG), Differential Thermal Analysis (DTG) and Thermal Expansion were performed in order to verify the thermal properties of the material. From the characterizations carried out it may be concluded that the synthesis of polymeric precursors via allowed obtaining pure phase of C3A at 1000°C low temperatures. The temperature of 1350°C it possible to obtain materials having grain morphology with uniform size and densely packed.
Immobilized Enzyme Gox with Ferrite CoFe2O4 and Hybrid CoFe2O4/APTS
Authors: Santos Polyana Tarciana Araújo , Araújo P.M.A.G. , Leal Elvia , de Albuquerque Izabelle L.T. , Conrado Líbia S. , Costa Ana Cristina Figueiredo de Melo
Published: June 2015

This work aims to evaluate the immobilization of glucose oxidase (GOx) with CoFe2O4nanoparticles and hybrids CoFe2O4/APTS. The nanoparticles were synthesized by combustion reaction and silanized using 3-aminopropyltrimethoxysilane (APTS). The samples were characterized by XRD, FTIR, magnetic measurements and immobilization of GOx. The results indicated single phase of spinel CoFe2O4and the addition of APTS did not alter the structure of the ferrite. The characteristic bands of spinel and characteristic bands were observed in the silane silanized sample proving the silanization of nanoparticles of CoFe2O4. The CoFe2O4nanoparticles and the hybrid had saturation magnetization of 58.0 and 53.0 emu/g and coercivity of 1.14 kOe and 1.15, indicating that the silanization does not interfere with the magnetism of the particles. The immobilized GOx was obtained with values of 0.047 and 0.050 mg/g efficiency of 84.86 and 80.30% for CoFe2O4/APTS and CoFe2O4.
The Usage of Ceramics in the Manufacture of the Lining of Temperature Sensors for the Oil Industry
Authors: Domingues R.O. , Yadava Yogendra Prasad , Sanguinetti Ferreira R.A.
Published: June 2015

In the oil production, many types of sensors are used in order to monitor some important parameters such as temperature, pressure and flow. These sensors are subjected to harsh operating conditions. Therefore they must present an inert and stable behavior in these conditions. The temperature sensors that are more suited to the oil industry are the Temperature Detectors by Resistance (TDR), because they have high accuracy and wide temperature range. Usually these devices are built with metals as detectors of temperature by encapsulated resistance in inert ceramics. The main objective of this research is to produce new ceramics of a Ca2AlZrO5,5 cubic complex perovskite structure for the encapsulation of temperature sensors. The stoichiometric amounts of the constituent chemicals, with a high degree of purity, are homogenized, through a solid state reaction in a high energy ball mill. They are then compacted by uniaxial pressing and calcined at 1200°C for 24 hours. Soon after, the tablet is crushed giving place to a ceramic powder and the analysis of X-ray diffraction is performed. According to the sintering behavior of the ceramic powder, the microstructure and the homogeneity are studied by the Scanning Electron Microscopy. The results are presented in terms of the potential of this ceramic for applications as components of temperature sensors.
Hot Pressing Sintering of ZrB2 with β-SiC Addition
Authors: Oliveira Juliani Mariah , Rocha Rosa Maria
Published: June 2015

Zirconium diboride (ZrB2) is a material of particular interest because of the excellent and unique property combination of high melting point, high electrical and thermal conductivity. In this work, the effect of addition of beta-silicon carbide (β-SiC) on hot pressing sintering of ZrB2 was investigated. Four compositions were studied with 0, 10, 20 e 30 vol% of SiC. ZrB2 powder and mixtures were prepared by planetary milling with SiC spheres during 4 h. Samples were sintered at 1850 °C/1h with a pressure of 20 MPa in argon atmosphere. β-SiC has undergone phase transformation to α-SiC during sintering. The addition of SiC increased densification with increasing of SiC content. The total densification of sample was 96.8 % of theoretical density for sample with 30 vol% of SiC and Vickers hardness was 19.9 ± 0.3 GPa.
The Influence of Dopants in the Grain Size of Alumina - A Review
Authors: Milak Pâmela , Minatto Flávia Dagostim , Faller Cristian , de Noni Jr. Agenor , Montedo Oscar Rubem Klegues
Published: June 2015

Ceramic materials present interesting properties and generate products that meet engineering requirements referring to this class for several applications. Aluminum oxide is a very good example of this class of materials, being applied widely in high technology areas especially where the abrasive and erosive wear are strongly demanded. Many factors interfere on the wear of alumina: material composition, characteristics of the used oxides, and the manufacturing process that defines the final microstructure. It is know that the grain size of the alumina has a strong influence on the wear rate and is the focus of several studies. The grain growth during sintering as well as the diffusion process can be controlled by using dopants in the alumina composition. Thus the aim of this paper is to present a review about the dopants interference on the grain size of alumina, which in turn influences the wear behavior of the alumina. The results described allow broad understanding on the subject
Effect of Sonochemical Technique on the Morphology and Crystallinity of Hydroxyapatite Nanoparticles
Authors: Lunz Juliana do Nascimento , Licona Karla Patricia Macedo , Antunes Ribeiro Alexandre , Delgado José Angel , Alonso Lizette Morejón , de Oliveira Marize Varella
Published: June 2015

Hydroxyapatite (HA) is the main mineral component of bones and teeth, and for this reason its synthetic analogous has been used with excellent clinical results as bone substitute. The biological apatite is typified as a poorly crystalline carbonate apatite (CHA) formed by nanosized particles with a great superficial area. This work aimed to study the influence of ultrasound technique on the morphology and crystallinity of nanoHA synthesized by chemical precipitation method. The nanoHA particles were obtained from CaCl2·2H2O and Na3PO4·12H2O raw solutions and a powerful ultrasonic sound (UP400S) was used at different conditions during the synthesis. X-ray Diffraction, Infrared spectroscopy, Chemical Analysis and Scanning Electron Microscopy were used to characterize the synthesized nanoHA particles. The results indicated that HA nanoparticles with nanorods morphology were obtained in all conditions. By Scherrer`s formula, the crystallite size was determined and it was found that the increasing in ultrasound amplitude enhances the nanoparticles crystallinity.
Electrochemical Impedance Spectroscopy: Evaluation of Drug Delivery System of Alpha-Tricalcium Phosphate Cement
Authors: Colpo Julio Cesar , Pigatto Caroline , Escobar Camila F. , Delbrücke Tiago , Jurado Jose R. , Sousa Vânia Caldas , Santos Luis Alberto
Published: June 2015

Tricalcium phosphate cement (α-TCP) can be used in various fields of health, including as drug delivery systems. The application of a biomaterial based on α-TCP could enable both the constant drug delivery as support and shape damaged muscleskeletics tissues until which can be regenerated by the organism itself, replacing the biomaterial, while maintaining stable levels of the drug in the organism. The aim of this study was to evaluate the release of gentamicin sulfate using the technique of electrochemical impedance spectroscopy in drug delivery systems of α-TCP. The results obtained in vitro study validated the proposed methodology for assessment of controlled drug delivery systems on the basis of α-TCP.
Aging Behavior of Commercial and Synthesized Dental Y-TZP Ceramics
Authors: Arata Anelyse , Moreira Bastos Campos Tiago , Machado João Paulo Barros , Yoshito Walter Kenji , Ussui Valter , de Lima Nelson Batista , Nisie Tango Rubens , Lazar Dolores Ribeiro Ricci
Published: June 2015

Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) is used for dental prosthodontics, however, it can present accelerated tetragonal to monoclinic phase transformation in oral environment. The aim of this study was to compare the behavior of a Y-TZP synthesized in laboratory by the coprecipitation method to a commercial Y-TZP, after hydrothermal aging in pressurized reactor (150°C/ 35 hours). The discs were sintered at 1520°C for two hours. The kinetics curve of phase transformation was determined through the data collect by XRD diffractograms treated by the Rietveld method. The experimental and commercial control groups did not present monoclinic phase. After 35 hours of aging, the experimental group presented 69% of monoclinic phase compared to 67% for the commercial group. Scanning electron microscopy and atomic force microscopy images suggested that the commercial group presented heterogeneity of grain size and that the experimental group was more homogeneous. All groups presented superficial degradation process.
Study of Process Variables for Organofilization of the Bentonite Clay from Cubati, Pb
Authors: Silva C.D. , Figueiredo J.M.R. , Pereira I.D.S. , Cartaxo J.M. , Neves G.A. , Ferreira H.C.
Published: June 2015

Bentonite clays, after treated with surfactants, are called organofilic clays. The objective of this work is the development of organofilic clays, using ionic surfactants, based on a variety of smectite from Cubati, PB, for application in organic media. The following materials were used: Superior Gray bentonite clay from the town of Cubati, PB, Brazil, and the ionic surfactants Praepagen WB® and Praepagen HY®. The clay was characterized with basis on the granulometric analysis by laser diffraction (AG), chemical composition by X-ray fluorescence (EDX), X-ray diffraction (XRD), thermogravimetric analysis (TG) and thermal differential (DTA). The clay was processed and then turned into sodic and later into organofilic clays. The results prove that there was intercalation of the ionic surfactant into the clay fraction, and that the process variables did not affect the organofilization process, but the surfactant type has influence on the process.
Evaluation of Morphology and Roughness of the Surface of a Ceramic Based on Lithium Disilicate, after Conditioning with Acid Hydrofluoric the 5% and 10%
Authors: Melo-Silva C.L. , Melo-Silva T.C.F. , Carvalho C.F. , Sudré J.P.S. , Freitas R.X. , Gouvêa J.P. , Lins J.F.C.
Published: June 2015

The aim of the study was to evaluate the difference in the surface of dental ceramics, the basis of lithium disilicate, varying the concentration and time of application of the acid. Samples of IPS e.max Press (Ivoclar) were divided into: G1-control; G2 hydrofluoric acid 10% - 20 sec; G3 hydrofluoric acid 10% - 40 sec; G4 hydrofluoric acid 5% - 20 sec G5 and hydrofluoric acid 5% - 40 sec. The samples were analyzed under SEM (Carl Zeiss) confocal microscope and (Carl Zeiss). The qualitative morphologic analysis showed that 40 seconds of conditioning promoted the dissolution of the vitreous component and the ceramic crystal display for the two concentrations. Hydrofluoric acid 10% showed higher values ​​of roughness. One can conclude that conditioning for 40 seconds is more effective than the 20 seconds for the two concentrations hydrofluoric acid and 10% promoted a higher surface roughness in the ceramic.
Europium-Doped Hydroxyapatite: Influence of Excitation Wavelength on the Eu3+ Luminescence in the Hydroxyapatite
Authors: Silva Flávia R.O. , de Lima Nelson B. , Gouveia Deiby S. , Ferreira Nildemar A.M. , Ussui Valter , Courrol Lilia C. , Bressiani Ana Helena A.
Published: June 2015

Hydroxyapatite (HA) doped with europium (HAEu) offers the advantage of making the hydroxyapatite a fluorescent biomarker, allowing their imaging through emissionin vivoandin vitrotests. Several authors had been based their studies about europium site occupation (CaI and CaII) in hydroxyapatite by the lanthanide ion luminescence, verifying the influence of the method of synthesis and concentration of the dopant ion. In this study HA nanoparticles doped with 1.4 mol% of trivalent europium were synthesized by co-precipitation method and thermal treated at different temperatures (600°C and 1200°C). A careful evaluation of the influence of the excitation wavelength of europium luminescence in the HAEu was performed and it has been verified that both the characteristics transitions of europium, at CaI and CaII sites, and the luminescent intensity are dependent on the excitation wavelength. The non-observance of this fact can lead to erroneous conclusions about the site occupation of europium in hydroxyapatites.
Characterization of Natural Clay Vermiculite, Expanded by Indirect Method for Energy and Microwave
Authors: Silva F.M.N. , da Silva Elaine Lope , dos Anjos I.F. , Fontgalland G. , Rodrigues M.G.F.
Published: June 2015

Vermiculite has a structure consisting of layered silicates surfaces interspersed with layers of water. When the expansion occurs intra lamellar clay water is removed. This paper aims to characterize the Vermiculite clay of Santa Luzia, Paraíba (Brazil) in their natural form, and after thermogravimetric treatments by classic X-ray diffraction analysis, thermal analysis and scanning electron microscopy. The results show that the method of expansion, using the technique of microwave energy is possible, however, the expansion factor is lower when compared to the indirect heating by the thermal expansion of the clay.
Changing of the Spontaneous Polarization in Niobate Nanoparticles Induced by Non Isovalent Doping
Authors: de Lima Caio Vinicius , Lima Nobre Marcos Augusto , Lanfredi Silvania
Published: June 2015

Ferroelectric niobates with tetragonal tungsten bronze TTB-type structure have shown great technology interest for application in pyroelectric detectors and piezoelectric transducers, sensor/filter in composite. The synthesis and structural characterization of the solid solution of iron doped potassium strontium niobate with stoichiometry KSr2(Fe0.25Nb4.75)O15-δprepared by modified polyol method were carried out. The highest crystallinity was obtained for the precursor powder calcined at 1150oC for 10 hours in oxygen atmosphere. The structural characterization was performed by X-Ray diffraction. The average crystallite size obtained was equal to 25 nm. The structural parameters were determined by Rietveld method giving a tetragonal system with space group P4bm. The spontaneous polarization of the solid solution was calculated, being equal to 39.46 μC.cm-2. Polihedra distortion and its correlation with niobium off-center are discussed.
Study of the Influence of Eu3+ Ions in the Bandgap of K2NdNb5O15 Nanopowders
Authors: Namikuchi Eliane Ayumi , Pires Ana Maria , Lima Nobre Marcos Augusto , Lanfredi Silvania
Published: June 2015

Ferroelectric semiconductors oxides with tetragonal tungsten bronze TTB-type structure doped with rare earth ions have been investigated in recent years due their promising optical properties. K2Nd(1-x)EuxNb5O15 nanopowders, where x = 0, 0.0025, 0.025, 0.05 and 0.1 were synthesized by the modified polyol method and characterized by X-ray diffraction and diffuse reflectance spectroscopy UV-Vis. Single phase and crystalline powders of tetragonal symmetry with non-centrosymmetric space group P4bm were obtained. The diffuse reflectance spectra were similar to the profile of a semiconductor material with the presence of thin transitions of Eu3+ in europium-doped K2NdNb5O15, as well as the transitions of Nd3+. The method of Kubelka-Munk was used for the estimation of bandgap energy. The values around 3.7 eV showed small variation with the concentration of Eu3+ ions in the K2NdNb5O15 host structure. The transitions were identified as direct ones type.
Multilayered Ceramic Composites – A Review
Authors: Minatto Flávia Dagostim , Milak Pâmela , Gislon Edivelton S. , Coelho Kétlin , de Noni Jr. Agenor , Montedo Oscar Rubem Klegues
Published: June 2015

Fracture toughness enhancement of ceramic materials through multilayered ceramic composites has been developed since 1990. Toughening mechanisms are based mainly on delamination, deflection, bifurcation or crack arrest effect. Delamination and crack deflection occur by means of weak interfaces. Bifurcation (and deflection as well) and crack arrest effects are result of residual stresses arising from the thermal expansion coefficient mismatch or phase transformation on alternating layers. The main manufacturing methods of these composites are slip casting of two ceramic materials, and stacking and pressing of ceramic tapes obtained by tape casting or rolling technics, followed by suitable sintering process. This review aims to present general aspects of research performed around the theme so far. It is verified that occurs the enhancement of ceramic toughness and reliability with this technic, so it is possible to enlarge its range of application in engineering.
Addition of Ornamental Stone Waste to Improve Distinct Formulations of Clayey Ceramics
Authors: Vieira Carlos Mauricio Fontes , Samarão Motta Thiago , Scarpini Cândido Verônica , Monteiro Sergio Neves
Published: June 2015

Clayey ceramics are being traditionally fabricated in the municipal area of Campos dos Goytacazes, Rio de Janeiro, Brazil, by a mixture of different clays to attend the technical specifications. In several cases, the simple mixture of clays is not able to grantee the required properties for a given fired ceramic product. In the present work, distinct formulation using two types of clays, with or without the addition of ornamental stone waste, were investigated for the effect on the technical properties of ceramics fired at 950°C. The results indicated that at this firing temperature the ornamental stone waste was not able to act as a fluxing agent and only the linear shrinkage was effectively improved.
Statistical Analysis of Degradation Data of Red Ceramic Pieces Incorporated with Ornamental Stone Waste
Authors: Piazzarollo Carla Bozzi , de Castro Xavier Gustavo , Albuquerque Fernando Saboya , de Almeida Maia Paulo Cezar , Alexandre Jonas , de Azevedo Afonso Rangel Garcez , Monteiro Sergio Neves
Published: June 2015

From the point of view of mechanical strength, ceramic materials exhibit dispersion results after being subjected to various levels of stress. However, there are no statistical surveys addressing the results efficiently. The present study aims to conduct with statistically survey, through the Minimum Lot Size, Chauvenet criterion and the Tukey range test. Specifically, the mechanical strength of red ceramic incorporated with ornamental rock waste and fired up to 700°C was analyzed, before and after degradation. The pieces were subjected to degradation of up to 1,500 hours by continuous leaching and of up to 10 months by the natural process. The results of the Tukey Test, before and after the degradation, showed statistical differences, ensuring that the data analysis was effective.
Influence of the Heating Rate on the Phase and Microstructural Transformations of Smectite Clays
Authors: Gonçalves Wherllyson Patrício , da Silva Valmir José , Gomes Josileido , de Araújo Neves Gelmires , Menezes Romualdo Rodrigues , de Lima Santana Lisiane Navarro
Published: June 2015

Clays are very important raw materials in the manufacturing of traditional ceramic products. The present study was intended to study the phase transformations of smectites submitted to thermal treatment in conventional stove, applying slow and fast cycles. We used three clays, two national and one imported, which were beneficiated and characterized by mineralogical analysis. Later, they were submitted to a thermal treatment at 1100, 1200 and 1250°C, with heating rate of 5 and 30°C/min, remaining under the maximum temperature for 60 minutes. We observed the presence of mullite peaks starting at 1100°C for all samples. It was verified that the sample with the highest alumina/silica ratio presented more intense mullite peaks, and the sample with the high MgO content, besides the mullite phase, also formed cordierite.
Influence of Particle Size in Brick’s Waste Reuse
Authors: Gonçalves I.L.M. , Gripa E.M. , Manfro R.L. , Almeida Valeria C.
Published: June 2015

Construction industry is the one that increases the most in Brazil, nowadays. On the other hand, this high development speed brings a concern with the destination of its leftovers. As it happens in most industrial processes, feedstock’s particles size is very important in reuse processes of brick waste and it is directly related with formed materials’ behavior. In this context, the main purpose of this study is to evaluate the influence of particle size in physical properties of specimen made of bricks’ waste through a characterization using Scanning Electronic Microscopy and X-Ray Diffraction. The specimen were made from three different selections of comminuted bricks’ particle size and then submitted to Flexural Strength tests. The results show that the material’s physical properties improve as the feedstock’s particle size decreases.
Effect of Superplasticizer Additives for Class Type Cpii E32 Cements
Authors: Grillo H.F. , Mariano Neide Aparecida , Ramos Alfeu Saraiva , Ferraço Fabio , Grillo K.V.F. , Maestrelli Sylma C.
Published: June 2015

Concrete mixing technology has spread with the development of water-reducing additives, enabling production of high quality products. Despite the discoveries and important technological advances, occurrences concerning the incompatibility between sealers and additives have been reported. The main incompatibilities occur between additive and cement of different brands, or different batches. This study investigated the influence of a superplasticizer on the properties of two cements of the same class (type CP II E 32), but different manufacturers. Two cements (without the presence of the additive) were characterized by physical, chemical and mechanical tests. The setting times for pastes made ​​from cement, water and superplasticizer mixtures were determined. The results showed a significant difference in physical, chemical and mechanical properties of cements, as well as those related to the hydration process thereof.
Study of Water Retention in Mortars Produced with Foundry Powder
Authors: Coelho Adenilson Roberto , Pereira Helena Ravache Samy , Faganello Luciana , Valentina Luiz Veriano Oliveira Dalla
Published: June 2015

The use of foundry waste in civil engineering is one of the most discussed issues by several environmental polities. This is caused by the excessive deposition of foundry waste on sanitary landfills. In order to find solutions to overcome this situation, this paper investigates the effect of the foundry powder concentration in the structure of mortars. Experiments were conducted with mortars processed at several concentrations of binders, aggregates and foundry powder. Results indicate that mortars built with foundry waste have water retention above to 75%. This observation indicates that mortars processed with foundry waste can be used in civil construction.
Evaluation of the Addition of α-Al2O3 on the Mechanical and Thermal Properties in Binding Geopolymer
Authors: da Costa Danubia Lisbôa , da Costa Farias Rosiane Maria , Braga Aluska Nascimento Simões , Menezes Romualdo Rodrigues , de Araujo Neves Gelmires
Published: June 2015

Several years ago the study on modification of existing materials that have enhanced properties has gained prominence. In this scenario, the geopolymeric binders, currently widely used in the construction industry have emerged. Thus, this study aimed to evaluate the influence of alumina addition on the mechanical and thermal properties of metakaolin in geopolymer binder. The geopolymers were synthesized from mixtures of metakaolin/alumina and sodium hydroxide, pressed and characterized by diffraction of X-ray and differential thermal analysis and thermogravimetric. Two types of alumina were used in different amounts (14% and 7%) in order to evaluate the effect of the load binder obtained. It can be seen that the incorporation of alumina into the system caused an increase in strength of products obtained as well as a reduction in total mass loss of the sample , especially when the use of fine alumina.
Concrete with Addition of Hollow Glass Microspheres
Authors: Ueki Peres Cindy Yuri , Munhoz Antonio Hortêncio , Miranda L.F. , Neto A. Cabral , Zandonadi A.R. , Peres R.M. , Diaz F.R.V.
Published: June 2015

The addition of hollow glass spheres is interesting to reduce the thermal conductivity of the concrete pieces. This work aims to evaluate the concrete with addition of hollow glass microsphere with different combinations of dosage in concrete concerning strength and workability. Slump tests were performed in each dosage of concrete in order to evaluate the effect of glass microspheres in concrete mix. In each age of curing concrete, bodies-specimens underwent ultrasound to estimate the homogeneity of concrete with hollow glass microspheres, and testing of compressive strength. The analysis of the results shows that for some formulations, the addition of hollow glass microspheres imparts high mechanical strength to compressive strength above 30MPa at all analyzed cure periods. The workability of the concrete had to be substantially reduced, showing no workability improvement due to the addition of hollow glass microsphere.
Study of the Stabilization/Solidification of Oily Sludge of Oil through of Scanning Electron Microscopy and Diffraction of X-Rays
Authors: Dias Joelma , de Brito André Luiz Fiquene , de Alcântara e Souza Bandeira Adna , Patrício Aline Cadígena Lima , Silva Muniz Ana Cristina
Published: June 2015

The objective of this study was to evaluate materials stabilized by solidification after incorporation of oily sludge of oil in a ordinary Portland cement matrix through analysis tests Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The research was divided into two main stages. In the first step the preparation of the specimens composed of cement, sand and oily sludge of oil and the second step was to evaluate the stabilization/solidification material via SEM and XRD analysis. The results of the XRD identified the characteristic peaks of portlandite, calcium silicate and ettringite. The same occurred with the SEM that detected the presence of the main products of the reactions of cement hydration. The results showed that the oily sludge of oil did not interfere with cement hydration reactions.
Use of Leather Residue in the Manufacturing of Soil-Cement Bricks
Authors: Santos Carol Ferreira Rezende , Sant’ana Alvarenga Rita de Cássia Silva , Ribeiro Benício Costa , da Silva Charles Luis , Rezende Ana Augusta Passos , Fassoni Délio Porto
Published: June 2015

This work is an analysis of incorporation of leather powder residue to soil in order to apply it in soil-cement bricks. The leather powder is a byproduct of the finishing step of leather manufacturing that contains chromium in its composition. This element, when in its hexavalent form, is carcinogenic. Experiments were performed regarding brick pressing, water absorption, simple pressing, leaching and solubilization so that the mixtures have the minimum requisites for using the brick. The doses were 0%, 10%, 15%, 20%, and 30% in volume of leather powder in soil. Only the 10% dose met the requisites of ABNT: NBR 8491:1984 that prescribes a minimum resistance of 2 MPa and absorption content lower than 20%. For this dosage, according to the limits stated in ABNT regulation NBR 10004:2004 , the leaching extract was classified as a Class II non-inert, which makes it possible to use it for civil construction purposes.
Evaluation of Incorporation of Special Vitreous Residues in Mass for Porcelain Stoneware: Physical and Mechanical Properties
Authors: Araújo A.M.B , Porto V.S. , Morais C.R.S. , Cavalcanti M.S.L.
Published: June 2015

This study aimed to technological alternatives for reuse of vitreous residues from fluorescent lamps, which cause damage to the environment. It was prepared mass to white ceramic with and without lamps residues replacing partially feldspar in proportions of 5% and 10%. Samples were molded and fired at 1000 ° C, 1100 ° C, 1150 ° C, 1200 ° C and 1250 ° C. Physical and mechanical tests were: water absorption, linear shrinkage and rupture by flexural modulus. Samples with 10% of residues reached stability at temperature less than 1250 ° C in all determined properties, confirming the feasibility of these residues in ceramic masses. To optimize the study, it was prepared other samples in proportions of 15% and 20% of waste, at the same level of burning and testing. Results obtained ratified the possibility of using these residues as a flux in ceramic slurries.
Addition of Paper Sludge Waste into Lime for Mortar Production
Authors: de Azevedo Afonso Rangel Garcez , Alexandre Jonas , de Castro Xavier Gustavo , Coelho França Fernando Cesar , de Andrade Silva Flavio , Monteiro Sergio Neves
Published: June 2015

Civil construction materials such as brick, concrete and mortar have been incorporated with compatible wastes aiming at both reducing costs and providing an environmentally correct destination for the waste. In the present work, a sludge waste from a paper industry was added in different amounts, up to 20 wt%, into the lime used to produce mortar in mixture with sand and cement. Standard consistency tests of the pasty, as-prepared, mortar as well as flexural and compressive tests of the solid, as-cured, mortar were performed. The results indicated that the addition of up to 10 wt% of paper sludge waste into the lime increased the mortar consistency and up to 20 wt% addition also improved the mechanical strength of the cured mortar.
Characterization of a Clay Body Used for Red Ceramics in São Sebastião, District of Campos dos Goytacazes, State of Rio de Janeiro, Brazil
Authors: de Azevedo Afonso Rangel Garcez , Alexandre Jonas , Barnabé Zanelato Euzébio , Picanço Oliveira Rafael , de Souza Rodolfo Cretton , de Castro Xavier Gustavo , Monteiro Sergio Neves
Published: June 2015

The municipal area of Campos dos Goytacazes in the northern region of the state of Rio de Janeiro, Brazil, is the state’s major industrial pole for red ceramic fabrication. The extensive clay deposits and easy to mine conditions have attracted more than one hundred ceramic industries to operate in the area. In particular, the district of São Sebastião contributes to the production of red bricks and tiles but the characterization of the existing clay and the quality of ceramic pieces has not yet been evaluated. Therefore the present work carried out an investigation of a typical clay body used in São Sebastião by means of its physical and chemical characteristics. The technological properties of red ceramics fabricated from this clay body and fired at temperatures of 700, 850 and 1100oC indicate that they comply with the mechanical strength requirements for masonry bricks. However water absorption is not satisfactory due to the excess of sand and lack of fluxing elements.
Synthesis of the MgAl2O4 Spinel Obtained via Combustion Reaction Using Glycerine from the Biodiesel as a Fuel for Producing Cellular Ceramics
Authors: de Moraes Graziela Guzi , Novaes de Oliveira Antonio Pedro
Published: June 2015

Magnesium aluminate (MgAl2O4) was synthesized via combustion reaction, using as fuel glycerine from biodiesel, for the production of cellular ceramics. A rheologically stable suspension was prepared in a ball mill and polyurethane sponges were impregnated. In order to define a firing cycle which would result in ceramic foams with high density ceramic walls (struts), synthesized and calcined powders were uniaxially pressed at 5.4 MPa and, after drying (110°C/120 min), fired at different temperatures (1450-1650°C) for 120 min. Thus, ceramic foams (fired at 1600°C/120 min) containing MgAl2O4 as the only formed crystalline phase with a porosity of 88 ± 0.5% and compression strength of 1.0 ± 0.3 MPa were obtained.
DNA-based identification of South Korean Megaloptera larvae with taxonomic notes
Authors: Jung Sang Woo , Vshivkova Tatyana S. , Bae Yeon Jae
Published: June 2015

Mitochondrial DNA (mtDNA) sequences, which serve as DNA barcodes, have been used to associate immature and adult stages of insects and to delineate species. The partial mitochondrial cytochromecoxidase subunit I (COI) gene sequences for South Korean Megaloptera (all known in the adult stage) were tested to identify undetermined larvae as a rapid and effective method from 31 specimens (16 adults and 15 larvae). The COI gene sequences distinguished all six known Megaloptera species, with a low genetic distance between larvae and adults (0.50±0.21%). Based on the COI gene sequences, we associated five types of larvae with known adults including the following four species of newly described larval stages:Sialis annaeVshivkova, 1979 (Megaloptera: Sialidae);Neochauliodes formosanus(Okamoto, 1910) (Megaloptera: Corydalidae);Parachauliodes asahinaiLiuet al., 2008 (Megaloptera: Corydalidae); andProtohermes xanthodesNavás, 1913 (Megaloptera: Corydalidae). The known larval stage ofSialis koreanaJung and Bae, 2012 (Megaloptera: Sialidae) was confirmed, and the morphological variation in the male genitalia ofSialis longidensKlingstedt, 1932 (Megaloptera: Sialidae) is discussed. A larval key to the six South Korean species of Megaloptera is provided.
Prevalence of Ureaplasma parvum in the area of Prato, Italy
Authors: Brunelli Tamara , Conti Antonella , Miglietta Patrizia , Rovinati Elisa , Ferri Daniele , Casprini Patrizia , Degl'Innocenti Roberto
Published: June 2015

In this study, the prevalence of Ureaplasma parvum in the area of Prato (Italy) was investigated. Samples from 1197 consecutive patients were analyzed. Our results showed that the prevalence of U. parvum was 33.6%, with a higher percentage in females than in males (40.6% vs 9%). In addition, the prevalence of U. parvum was significantly lower in older patients.
Phenotypic classification of multidrug-resistant Klebsiella through MALDI-TOF mass spectrometry
Authors: Di Taranto Anna , De Nittis Rosella , Fagioni Marco , Rollo Tiziana , Cella Paola , Antonetti Raffaele
Published: June 2015

Background. Resistance to carbapenems in Klebsiella pneumoniae infections could compromise therapy efficiency in hospitals. In Italy, the percentage of K. pmeumoniae resistant to carbapenems blood-isolated is 35%.
Materials and Methods. Seventy-three multidrug-resistant K. pneumoniae clinical isolates coming from Foggia (Italy) have been phenotypically classified through matrix assisted laser desorption/ionization-time of flight mass spectrometry between February and May 2014 in order to locate an eventual infectious outbreak.
Conclusions. Classification of microbial isolates is essential to this purpose and starts from phenotypic methodologies to the most complex genotypic methods. Among these, mass spectrometry utilization appears to be a simple, useful and quick instrument in a clinical microbiology laboratory.
Emergency management in bacterial meningitis and sepsis: application of real time-polymerase chain reaction and FilmArray technology performed directly on cerebrospinal fluid and blood samples
Authors: Bianchi Loria , Napoli Zaleida , Donati Swan , Lencioni Patrizia , Santoni Fabiano , Lari Riccardo
Published: June 2015

Background and Aims. Bacterial meningitis and sepsis are medical emergencies where tests with a high sensitivity and short turn around time (TAT) are crucial for an early targeted therapy. Aim of this study was the evaluation of an optimal diagnostic strategy for infectious meningitis/sepsis management, assessing seven methods: cerebrospinal fluid (CSF) physical-chemical examination, CSF cultural tests (CCT), Gram stained smears (GSS), CSF latex agglutination test (CLAT), blood culture (BC), Real-Time (RT)-PCR and FilmArray Technology (FAT) performed directly on CSF/blood.
Materials and Methods. Samples of CSF (240), blood (180) and cavitary fluids (9) were tested by commercial RT-PCR (Eurospital and Liferiver kits) and traditional methods. Positive samples (BC and RT-PCR) were tested by FAT (Blood Culture Identification Panel, Biofire, Salt Lake City, UT, USA) performed directly on CSF, blood and cavitary fluids.
Results. In CSF, GSS, CLAT, CCT, RT-PCR and FAT sensitivity was 41%, 35%, 41%, 100% and 62,5%, respectively. In blood, BC, RT-PCR and FAT sensitivity was 96%, 70% and 44%, respectively. TAT was 48-96 hrs, 3 hrs and 1 hr and NPV was 98%, 89% and 57%, respectively.
Conclusions. For sepsis management, RT-PCR is faster than BC (3 hrs vs 24-72 hrs), but limited by a low overall sensitivity (70%), due to the low number of detectable pathogens; FAT, performed directly on positive BC should replace biochemical identification (Vitek 2, Biomérieux Marcy-l’Étoile, France) reducing TAT (1 hr vs 12 hrs). For meningitis management, RT-PCR is the most sensitive and rapid method used in routine and emergency regimen. It is cost effective and it represents the gold standard for diagnosis and follow-up of patients under treatment. For meningitis management, FAT, with a higher sensitivity and rapidity and an easier and objective interpretation, should replace CLAT and GSS in emergency regimen.
Evaluation of anti-measles and anti-mumps vaccination coverage in a cohort of youth in South-Centre of Sicily, Italy
Authors: Lo Magno Claudia , Bellomo Liborio , Collodoro Rosalba , Di Forti Giuseppina
Published: June 2015

This study examined a cohort of young people from South Centre Sicily, Italy, in order to evaluate anti-measles anti-mumps vaccination coverage. It is shown that, in proportion, an antibody protection against mumps is greater than an antibody protection against measles and also it causes acute episodes in some subjects vaccinated.
Laser-assisted strategy for reflux abolition in a modified CHIVA approach
Authors: Gianesini Sergio , Menegatti Erica , Zuolo Michele , Tessari Mirko , Spath Paolo , Ascanelli Simona , Occhionorelli Savino , Zamboni Paolo
Published: June 2015

The aim of this study was to assess feasibility and efficacy of an endovenous laser (EL) assisted saphenous-sparing strategy in chronic venous disease (CVD). Fourteen CVD patients (C2,3,4s Ep As Pr1,2,3) underwent a saphenofemoral junction (SFJ) treatment by EL just from below the superficial epigastric vein downward for a limited tract, together with a flush ligation of the incompetent tributaries of the great saphenous vein (GSV) along the leg. The following GSV parameters were assessed 15 cm below the SFJ: reflux time, caliber, peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI). Venous clinical severity score and the Clinical, Etiological, Anatomical, and Pathophysio logical (CEAP) classification clinical classes were assessed. At 1 year follow up 3 cases were considered failures because of a GSV thrombosis, even if they presented a GSV recanalization with a laminar flow within at the 2 years follow-up. Eleven procedures succeeded because neither minor nor major peri-procedural complications were reported, apart 2 cases of self-healing bruising. In these last 11 cases the procedure led to a GSV reflux suppression (from 3.1±0.4 s to a retrograde laminar draining flow), to a GSV caliber reduction (from 9.4±0.5 to 3.1±0.2 cm, P<0.001), to a PSV reduction (from 50.2±4.6 to 18.4±3.5 cm/s, P<0.001), to a RI reduction (from 0.9±0.2 to 0.51±0.2, P<0.005) and to an oscillatory flow suppression (EDV from -8.9±1.6 to 6.2±2.3 cm/s, P<0.001). Both CEAP and venous clinical severity score improved from 3 to 1 (P<0.001) and from 7±2 to 2±1 (P<0.05), respectively. The GSV flow reappeared below the shrunk tract draining into the re-entry perforator. Sapheno-femoral reflux suppression can be obtained by just a GSV segmental closure. An almost 80% of success rate of the present investigation paves the way for an even wider diffusion of endovenous techniques, moreover erasing the surgical requirements for those who would like to perform a saphenoussparing strategy. In this way new devices could be used inside equally innovative strategies.