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Synthesis of Poly(propylene)/Graphite Nanocomposites by in Situ Polymerization

Macromolecular Symposia 2011年第1期299-300卷

作者： Larissa Stieven Montagna Fabiana de Carvalho Fim Griselda Barrera Galland Nara Regina de Souza Basso Pos-Graduation Program in Materials Engineering and Technology Pontifical Catholic University of Rio Grande do Sul Av. Ipiranga 6681 Porto Alegre 90619-900 – Brazil Chemical Institute University Federal of Rio Grande do Sul RS Brazil Av. Bento Gonçalves 9500 Porto Alegre 91570-970 – Brazil

This work presents the synthesis of polypropylene/graphite nanocomposites by in situ polymerization using the catalytic system C 20 H 16 Cl 2 Zr ( rac -ethylenebis (indenyl)zirconium(IV)) dichloride/Methyoluminoxane (MAO). 60 nm graphite nanosheets (GNS) were obtained by means of the chemical exfoliation, thermal and ultrasound treatment. GNS previously treated with MAO were added into the reactor at percentages of 0.3, 1.0 and 2.2% (w/w) in relation to nanocomposite yields. The morphology of graphite nanosheets and nanocomposites was studied by Scanning Electron Microscopy (SEM). Moreover, the structural properties of natural graphite flake (NGF), graphite nanosheets (GNS) and nanocomposites were observed through the X-Ray diffraction (XRD) analysis and by Transmission Electron Microscopy (TEM).

关键词： graphite nanosheets in situ polymerization nanocomposites poly(propylene)

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Porcelain tiles produced by the dry route

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InterCeram: International Ceramic Review 2010年第1期59卷 13-17页

作者： Melchiades, F.G. Daros, M.T. Zanelatto, F.C. Boschi, A.O. Laboratório de Revestimentos Cerâmicos - LaRC Departamento de Engenharia de Materiais - DEMa Universidade Federal de São Carlos - UFSCar São Carlos Brazil Post Graduation Program in Materials Science and Engineering - PPGCEM UFSCar São Carlos Brazil

In Brazil, 70 % of the ceramic tile output is at present produced by the dry route. Increasing global environmental concerns and the recognition of the central role played by water have pointed towards encouraging dry processes. In this context, the objective of the present work was to study the feasibility of producing high quality porcelain tiles by the dry route. A brief comparison of the dry and wet routes for producing traditional ceramic tiles shows that there are two major differences: the particle sizes obtained by the wet route are usually considerably finer and the different minerals usually mix better with the wet route. The present work studied the relative importance of these differences and looked for raw materials and operational conditions that would result in better performance and glazed porcelain tiles of good quality.

关键词： Porcelain

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An efficient two-level preconditioner based on lifting for FEM-BEM equations

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Journal of Microwaves and Optoelectronics 2010年第2期9卷 78-88页

作者： Pereira, Fabio Henrique Afonso, Marcio Matias De Vasconcelos, João Antônio Nabeta, Silvio Ikuyo Industrial Engineering Post Graduation Program UNINOVE University São Paulo Brazil Electrical Engineering Department Federal Technology Education Center CEFET Minas Gerais Brazil Electrical Engineering Department UFMG Minas Gerais Brazil Electrical Machine and Drives Lab São Paulo University GMAcq/USP São Paulo Brazil

The system resulting from the coupled Finite Element Method and Boundary Element Method formulations inherits all characteristics of both finite element and boundary element equation system, i. e., the system is partially sparse and symmetric and partially full and nonsymmetric. Consequently, to solve the resulting coupled equation system is not a trivial task. This paper proposes a new efficient lifting-based two level preconditioner for the coupled global system. The proposed approach is applied to solve the coupled systems resulting from the electromagnetic scattering problem and its performance is evaluated based on the number of iterations and the computational time. Traditional methods based on incomplete and complete LU decompositions are used for comparison. © 2010 SBMO/SBMag.

关键词： Boundary element method

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A Study of the Effect of Illumination Conditions and Color Spaces on Skin Segmentation

A Study of the Effect of Illumination Conditions and Color S...

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Brazilian Symposium on Computer Graphics and Image Processing (SIBGRAPI)

作者： Diogo Kuiaski Hugo Vieira Neto Gustavo Borba Humberto Gamba Post-graduation Program in Electrical Engineering and Industrial Informatics Federal University of Technology of Paraná (UTFPR) Curitiba Parana Brazil

This work aims at investigating the influence of luminance information and environment illumination on skin classification. We explore Bayesian approaches to perform automatic classification of human skin pixels on digital images, using color features as input. Two probabilistic skin color models were built on different color spaces (RGB, normalized RG, HSI, HS, YCbCr and CbCr) and tested in a task of automatic pixel classification into skin and non-skin. Analyses of classification performance were done by presenting an illumination controlled image database containing images acquired in four different illumination conditions (shadow, sun, incandescent and fluorescent lights) to these classifiers. Our experiments show that building probabilistic skin color models using the CbCr color space generally improves performance of the classifiers and that best performance is achieved in shadow illumination.

关键词： Lighting Skin Image segmentation Bayesian methods Humans Pixel Digital images Roentgenium Automatic testing Image analysis

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Psim mathematical tools to simulate pem fuel cells including the power converter

Psim mathematical tools to simulate pem fuel cells including...

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Annual Conference of Industrial Electronics Society

作者： L. P. Lima F. A. Farret D. B. Ramos F. Z. Ferrigolo H. W. Stangarlin J. G. Trapp A. B. Serdotte Center of Studies in Energy and Environment (CEEMA) Post-Graduation Program in Electrical Engineering Center of Technology Federal University of Santa Maria Santa Maria Rio Grande do Sul Brazil

This paper presents a mathematical model for proton exchange membrane fuel cells (PEMFCs) taking into account the basic electrochemical equations but including the boost power converter. This approaching is suitable for design and simulation of power electronics systems with embedded FCs as power supplies. The simplified model uses the Kirchoff's voltage law (KVL) applied to the conventional electric equivalent model of PEMFCs. This work is fully implemented in PSim¿ as a general mathematical model and referred to literature data including the boost converter, mostly used as the power interface for FCs. In this way, the model is fully evaluated by viewing the interface just as a power converter.

关键词： Fuel cells Mathematical model Power system modeling Protons Biomembranes Equations Power electronics Power supplies Voltage Kirchhoff's Law

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Organizational human factors as barriers to energy efficiency in electrical motors systems in industry

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ENERGY POLICY 2007年第11期35卷 5784-5794页

作者： Sola, Antonio Vanderley Herrero Xavier, Antonio Augusto De Paula [a]Department of Industrial Automation Campus Ponta Grossa Federal University of Technology Paran¨￠ Brazil [UTFPR] Av. Monteiro Lobato Km 4 CEP: 84016-210 Brazil [b]Post Graduation Program in Production Engineering [UTFPR] Brazil

This paper presents a study accomplished in the State of Parana in Southern Brazil, aiming at verifying the correlation between organizational human factors (OHF) and the level of energy losses in organizations. The purpose is to subsidize the formularization of institutional policies in organizations to improve the energy efficiency in the productive sector. The research was carried out in ten industries of the following sectors: pulp and paper;food;wood and chemical products. The losses of electric energy were determined in motor systems with the aid of a mathematical model and the evaluation of 27 OHF identified in the literature review was made with the supervisors in the industries by means of a structurized questionnaire. Seven OHF had presented significant correlation with energy losses and six of them are inversely proportional to the losses, in accordance with linear regression analysis. The inversely proportional factors to the losses also with significant correlation are considered determinative OHF and constitute barriers for energy efficiency in organizations. These barriers are linked with the following organizational areas: management system;education of employees;strategical vision. The study recommends the implementation of the determinative OHF in organizations as a way to transpose the human barriers for energy efficiency. (C) 2007 Elsevier Ltd. All rights reserved.

关键词： energy efficiency energy losses organizational human factors

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Xylanase production in solid-state fermentation using agroindustrial residues with Aspergillus niger

Xylanase production in solid-state fermentation using agroin...

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CHISA 2006 - 17th International Congress of Chemical and Process engineering

作者： Maciel, G.M. Vandenberghe, L.P.S. Fendrich, R.C. Haminiuk, C.W.I. Medeiros, A.B.P. Paca, J. Soccol, C.R. Bioprocess Engineering and Biotechnology Division Federal University of Paraná Coronel Francisco H.S.S. n. 100 Curitiba/PR Brazil Post-Graduation Program of Food Technology UFPR P.O. Box 19011 Curitiba/PR Brazil Institute of Chemical Technology Prague Technická 5 166 28 Praha 6 Czech Republic

No abstract available

ISBN: (纸本)8086059456

No abstract available

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Analysis of A 2D cathodic protection system for a buried slender structure with the dual boundary element method

Analysis of A 2D cathodic protection system for a buried sle...

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European Congress on Computational Methods in Applied Sciences and engineering, ECCOMAS 2004

作者： De Lacerda, Luiz A. De Oliveira, Paulo A. Lázaris, José Da Silva, José M. LACTEC - Institute of Technology for Development Materials Department Centro Politécnico Cx. P. 19067 Curitiba Brazil PPGMNE - Post-Graduate Program on Numerical Methods in Engineering UFPR - Federal University of Paraná Curitiba Brazil

In this paper a boundary element formulation is developed and used for the analysis of cathodic protection systems of buried slender structures, such as foundations of electric transmission line towers. The foundation is basically a truss structure and the slenderness of the pieces composing it, brings numerical difficulties into the classical boundary element method. To avoid this problem, the dual boundary element method is implemented: combination of standard and hypersingular integral equations to form a mathematically well-posed system. A simple experiment is carried out where a galvanized metallic sheet is buried alongside two Copper electrodes (anodes) in parallel, with the objective of simulating a two-dimensional problem. The soil resistivity properties are measured along the depth and the non-linear polarization curves describing the relation between the current density and the electrochemical potential at the metallic sheet is investigated. Two situations are analysed: a) current is injected into the ground through both electrodes;b) current is injected through only one of the electrodes. In the numerical implementation, the soil is modeled as a homogeneous layered half-space with a different property for each layer. The validity of the proposed dual approach is discussed and compared with the measurements of potential at the ground surface.

关键词： Boundary element method

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FLAMMABILITY AND TOXICITY OF COMPOSITE-materials FOR MARINE VEHICLES

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NAVAL ENGINEERS JOURNAL 1990年第5期102卷 45-54页

作者： SEVART, JL GRIFFIN, OH GURDAL, Z WARNER, GA Jeffrey L. Sevart:is a native of Kansas and a 1985 graduate of Kansas State University with a B.S. in mechanical engineering (magna cum laude). After working as a stress analysis engineer at Boeing Military Airplane Company in Wichita Kans. he attended Virginia Polytechnic Institute and State University and received an M.S. in engineering mechanics in February 1988. He currently resides in Akron Ohio working as a research engineer in tire composites research at The Goodyear Tire and Rubber Company. O. Hayden Griffin Jr.:received his B.S. and M.S. in mechanical engineering from Texas Tech University in 1970 and 1971 respectively. He received his Ph.D. in engineering mechanics from Virginia Polytechnic Institute and State University in 1980. Prior to joining the faculty of Virginia Polytechnic Institute and State University as associate professor of engineering science and mechanics in September 1985 he was employed at the U.S. Naval Surface Warfare Center (Dahlgren Virginia) BF Goodrich Tire Group (Akron Ohio) the Bendix Advanced Technology Center (Columbia Maryland) and the Johns Hopkins University Applied Physics Laboratory (Laurel Maryland). He is currently an associate director of the Virginia Institute for Material Systems. He is a registered professional engineer in Virginia and is a member of the American Society of Mechanical Engineers and the American Society for Composites. Zafer Gürdal:received his M.S. in mechanical and aerospace engineering from Illinois Institute of Technology in 1981 and his Ph.D. in aerospace engineering from Virginia Polytechnic Institute and State University in 1985. He worked as a research associate in the Aerospace and Ocean Engineering Department at Virginia Tech before joining the Engineering Science and Mechanics Department as an assistant professor in September 1985. Professor Gürdal's research interests include: composite structures failure mechanics of composites structural optimization and damage tolerant design. He is a member of the American Institute

Characteristics of both thermoplastic and thermoset composite materials as they pertain to marine vehicle applications are discussed. Comparison of various material selection factors such as strength, damage and moisture resistance, and flammability and toxicity as well as cost and availability of thermoset and thermoplastic composite materials are presented. Methods for testing and reducing the flammability and toxicity are discussed. Many commercially available composite systems are reported to provide favorable characteristics for marine applications. Although there seems to be a need for improved production technology for thermoplastics, they present potential advantages in physical properties over thermoset composites.

关键词： Composite materials

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THE NO FRAME CONCEPT - ITS IMPACT ON SHIPYARD COST

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NAVAL ENGINEERS JOURNAL 1984年第3期96卷 218-232页

作者： NAPPI, NS WALZ, RW WIERNICKI, CJ Natale S. Nappi:graduated from City College of New York in 1954 with a B.S. degree in civil engineering and received his M.S. in civil engineering from the Polytechnic Institute of Brooklyn in 1959. He began his professional career in 1954 at the New York Naval Shipyard as a naval architect (structures) performing detail structural design and fabrication studies for CVAs LPDs DDs and CGs and eventually became a supervisory naval architect (structures). From 1965 to 1973 he was a member of the staff of the Computer-Aided Design Division at the David Taylor Naval Ship Research and Development Center (DTNSRDC). As such he was involved in the development of the computer structural design tool the SSDP (in association with Frank M. Lev) and automated detail design programs (CASDOS). His current position is Senior Naval Architect Consultant in the structural integrity group of the Ship Structures Division Structures Department DTNSRDC. Mr. Nappi is the author and co-author of numerous technical papers and reports covering a wide spectrum of topics such as automated structural design process design for producibility and survivability material weight and cost trade-off studies and structural weight determination for high performance ships (i.e. SES SWATH HYSWAS). He has lectured on the subjects of design for survivability and ship structures at the Naval Post Graduate School and MIT. He is a member of ASNE ASCE U.S. Naval Institute Sigma Xi and is a registered Professional Engineer in the State of New York. Mr. Nappi was a member of the NAVSEA working commitee for the computer supported design planning effort and is currently a member of the DTNSRDC ASSET Advisory Committee. Ronald W. Walz:graduated in 1974 from Pennsylvania State University with a B.S. degree in civil engineering. He began his professional career in 1974 at the David Taylor Naval Ship Research and Development Center as a structural engineer in the structural design concepts group of the Ship Structures Division Structures Department.

A proposed cost effective alternative to current U.S. Navy structurally configured hulls is presented in this paper. This proposed design for producibility concept involves the elimination of structural stanchions and transverse web frames. The potential impact of this “no frame” concept on structural design, weight and construction and material costs for naval surface frigates and destroyers is reflected in 1) reduced costs for the installation of distributive systems and 2) a reduced number and complexity of structural details providing a more reliable and less costly structure. This study was performed in three parts: 1) Determine the most feasible length between bulkheads without frames; 2) Using this length perform detail weight studies and construction and material costs analysis comparison on a 72-foot long hull module, with and without frames, for a FFG-7, and 3) Estimate the saving in man hours of labor on the installation of distributive systems and shipfitting for an FFG-7. For the feasible length studies on the “no frame” structural configuration, thirty-seven strength, weight and vertical center of gravity studies were performed on two ship classes; twenty-two on the FFG-7 class and fifteen on the DD-963 class. The detailed weight studies and construction and material cost analyses were conducted for FFG-7 “no frame” and “as built” modules. Results indicating the “no frame” concept module was 6.8% heavier and 14.8% less costly than the “as built” module. For the impact of an FFG-7 “no frame” structurally configured hull on the cost of labor required for the installation of distributive systems and for other functional work such as ship fitting, welding, and electrical, this study indicated a reduction of 169,206 labor hours per ship, representing 7.12% of the total required man hours to fabricate an FFG-7 class ship. With the employment of the “no frame” concept, certain areas of significant concern and potential risk were addressed. These include: 1) t

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