Report of the Brazilian Committee for Phase Diagrams of Materials

Transcrição

1 Report of the Brazilian Committee for Phase Diagrams of Materials 2012 APDIC Meeting Berkeley, USA June 2012

2 Highlights Hosting X CAPHAD Hosting the 2011 APDIC meeting Intense activity in steelmaking, oil and nuclear industries and in collaboration with these industries.

3 ABM Conference 2012 and X CAPHAD retrospect Organizing of the Phase Diagram Seminar in the 67 th International ABM Conference, Rio de Janeiro, RJ, July 2012 Organizing a Computational Thermodynamics Workshop together with the 67 th Conference. Already 28 registered! X CAPHAD: Contributions by USIMINAS, V&M, Villares Metals, Aperam, ArcelorMittal Monlevade, NS, PUC-RIO, USP, EE-USP, UFF. Strong Brazilian participation.

4 UFOP Prof Carlos Silva The Committee in 2011 USIMINAS Dr Joao uiz Antunes EE-USP -orena Prof. G. Coelho, Prof C Nunes Calc./Exp Intermetallics UFF-Volta Redonda Prof. A. Costa e Silva Prof Flavio Ferreira Calc./Exp., St eels,slags Intermetallics Catholic University -Rio (PUC) Prof. R. Avillez - Exp./Calc. E.MAT, Coatings Prof. F.Rizzo - Exp. Coatings, Oxidation APERAM eandro N Viera AM Monlevade Dr Joaquim C Neto UFSCar-São Carlos Prof. W.Botta Dr E. Borba. Exp.Alloys, Amorphous mat. UFRJ Prof Dilson Universidade Estácio/INT Prof Brant Villares Metals Dr Celso Barbosa GERDAU- Steelmaking Dr Raimundo Fortes Mauricio W Scal IPT-São Paulo Dr. M Bocallini Exp.(calc.) Slags, liquid metals USP-São Paulo Prof.H.Goldstein Dr.C.Schoen, Prof Capocci Exp/Calc. Alloys UFRGS-Porto Alegre Prof Villela, Prof Heck UNISINOS- Prof Moraes Exp./ Calcl. Alloys

5 APERAM Research Centre South America RESEARCHERS eandro Nakamura Alves Vieira, MSc Marco Antônio da Cunha, PhD Fabrício uiz de Alcântara, MSc Tarcísio Reis Oliveira, PhD CURRENT PROJECTS CONCUDED: Precipitation of secondary phases in low-c 3%Si multi-component Steel Evaluation of effect of alloying elements of microstructure and microsegregation of ferritic stainless steels Estimates of the effect of Cr carbides on austenitic stainless steel corrosion resistance via Computational TThermodynamics Hot rolling load prediction for electrical steels with different Si contents using Computational Thermodynamics ONGOING RESARCH Combined effects of Nb and N+C on stabilized ferritic stainless steel phase transformations AlN precipitation kinetics in high Si steel Computational thermodynamics evaluation of de-c and nitriding of high Si steels

6 APERAM (cont.) Publications and systems Vieira,. N. A. et. al., Microstructural aspects and computational thermodynamics of secondary phase precipitation in Fe-Si 3%Wt. steel, X Calphad, Rio de Janeiro, May Systems (related to Stainless Steels and high Si electrical steels) Fe-C-Si, Fe-Si-Al, Fe-Si-N, Fe-C-Cr, Fe-C-Ni, Fe-Cr-Ni

7 ArcelorMittal Monlevade Investigators Humberto uiz Gama de Magalhães (moved to AM Trinidad Tobago) Joaquim Gonçalves Costa Neto Angelo Máximo Fernandes Marins César Takaci Sato Team Reduction 4 Steelmaking 4 Refractories 1 Rolling 4 Techical assistance 6 Total 23

8 ArcelorMittal Monlevade Ongoing and concluded projects Reducing segregation in fine wire steel Increasing acceptance rate inclusions in clean steels Development of steel wire for mechanical de-scaling (no chemical descaling) Inclusion engineering, slag development for specialty steels, including steels for off-shore applications Inclusion control during full steelmaking process Improved performance clean shock absorver rod steel Control of retained austenite in wires for welding electrode core Use of melt shop slime (wet dust) as a recycled raw material in the sintering plant.

9 GERDAU (ong Products Steelmaker) Defining an optimum Mn/Si ratio for casting low Mn, Si steels without slag formation in the mould. Studies of the relationships between Ti and O to guarantee effective B addition for hardenability. Defining optimum slag basicity for high-c steels to avoid clogging and control non-metallic inclusions. Evaluation of the Si-O-C-slag equilibrium in high carbon steels deoxidized by Si. Evaluation of inclusions in the CaO - SiO2 - Al2O3 with Ca injection or Ca-Si additions. Study of the relations between [O], [N] e [H] in the formation of porosity in C-Mn continuous cast steel. Evaluation of slag adjustment. Evaluation of the solubility of 2CaO.SiO2 in slags formed in dolomitic ladle to enhance ladle coating. Determination of saturation MgO and optimization of CaF2 additions. Study of the BN precipitation ranges to avoid face cracks in low-c steels in continuous casting. C. Evaluation of the Fe-Nb-V-Ti-C-N system in respect to the precipitation of carbonitrides for high strength rebar in rolling. Improvement of castability of steels containing Ca-S-Al-O, with Al and S controlled. Slag foaming in Electric Arc Furnace. Phase precipitation. Solubility of (Fe,Mg)O.

10 aboratório Nacional de uz Síncrotron NS ( Group: Electron Microscopy aboratory (ME) Researchers: Principal: Dr. Antonio J. Ramirez Students: Jimy Unfried S. (PhD candidate) Andre Yoshio Goto Eduardo Bertoni da Fonseca Main areas of interest: Welding, welding metallurgy and phase transformations, electron microscopy: Phase transformation simulation in Ni-based superalloys (Ni-Cr-Fe) with Ti, Nb, Mo e Hf HSA microalloyed steels, stainless steels, including duplex: transformation in fusion and friction welding.

11 IPT - São Paulo SP Research staff Dr Mario Bocallini Jr +3 PhD and 3 engineers Research areas Pyrometallurgical processing of metals and oxides. Process development Applications Alloy design and heat treatment optimization for high Cr cast irons used for wear parts in the steel and mining industries. Alloy design and casting process developent for multi-component cast irons (Fe- C-Cr-Mo-W-V) Thermodynamic modelling of slags in the Si refining process for the production of solar grade Si (interactions Si-slag, Si-atmospheres, Si-vacuum) Evaluation of non-metallic inclusion formation in low alloy steels Projetos

12 PUC-Rio de Janeiro RJ Research staff: Prof. Fernando Cosme Rizzo Assunção Prof. Roberto Ribeiro de Avillez Research areas: Thermodynamics of steel processing (TECOMAT, oxides) Steel coatings (Galvanizing and other zinc coating processes). High temperature corrosion. Microstructural evolution in steels (Q&P process). Nanostructured oxide synthesis. Negative thermal expansion coefficient materials.

13 PUC Prof Rizzo s Projects Materials development for energy production from fosssil fuels with low CO 2 emission Synthesis, Processing, Modeling and Characterization of Functional Oxides Synthesis and Characterization of Ceramic Oxides/ Materials with Negative Thermal Expansion Study of the photocatalytic degradation of toxic gases resulting from FCC process and development of photocatalytic materials Morphological and crystallographical characterization of catalysts Characterization of catalysts by Transmission Electronic Microscopy Characterization of nanomaterials by X-ray diffraction Development of thermoplastic based nanocomposites using titanate nanotubes and nanofibers Qualification of wet welding procedures Implementation of aboratory for Photocatalysis for study of pollutant gases reduction forming during refinement of petroleum Characterization of the materials important for Petroleum Industry (Catalysts and advanced materials) by XRPD and TEM High Temperature Corrosion in Industrial Systems of Oil and Gas Field

14 PUC- Prof Avillez Roberto R. de Avillez Rogério C. S. Navarro Recent Publications on oxides Navarro, R.C.S. ; Gomez, A.M.S. ; de Avillez, R.R.. Heat capacity of stoichiometric Al2MnO4 spinel between 2 and 873 K. Calphad (New York), v. 37, p , Siqueira, Rogério Navarro Correia de ; Avillez, Roberto Ribeiro de ; Gomez, Angelo Márcio de Souza. NOVO MODEO DE ENERGIA DE GIBBS PARA O ESPINÉIO A2MNO4. Tecnologia em Metalurgia Materiais e Mineração, v. 8, p , 2011.

15 Universidade Federal do Rio Grande do Sul - UFRGS Research Staff - BIEEFEDT, Prof. Dr. Wagner Viana - asid aboratório de Siderurgia, Universidade Federal do Rio Grande do Sul UFRGS. - VIEA, Prof. Dr.-Ing. Antônio Cezar Faria aboratory Coordinator, aboratório de Siderurgia UFRGS - HECK, Prof. Dr.-Ing. Nestor Cezar - Coordenador do NTCM Núcleo de Termodinâmica Computacional para a Metalurgia UFRGS - KUG, MSc. Jeferson eandro - doutorando CNPq. - SIVA, MSc Daniel dos Reis Silva - doutorando CNPq. - GIRARDI, Marília mestranda CNPq Research Themes Engineering steel, Free cutting steel; non-metallic inclusions; hydrogen in steelmaking slags; mold slags; coal ashes. Industrial applications include also stainless steels.

16 UFRGS- Highlights (cont.) Course during the 43º Steelmaking Seminar ABM: Thermochemical Computer-aided Steelmaking in Industrial Practice - featuring FactSage and derived software: Prof. Dr. Klaus HACK Gesellschaft für Technische Thermochemie und -physik mbh. Reinisch-Westfälische Technical University-Aachen, Germany Dr. Klaus Hack visit to UFRGS may VIEA, Prof. Dr.-Ing. Antônio Cezar Faria: Paraninfo da Turma de Engenheiros Metalúrgicos 2011/2, Universidade Federal do Rio Grande do Sul. Prêmio Intendente Câmara, Associação Brasileira de Metalurgia, Materiais e Mineração-ABM. Prêmio Antônio Mourão Guimarães, Associação Brasileira de Metalurgia, Materiais e Mineração-ABM.

17 UFRGS - Publications BIEEFEDT, Wagner V. ; VIEA, Antônio Cezar Faria. ESTUDO TERMODINÂMICO DE INCUSÕES NÃO-METÁICAS EM AÇO ACAMADO AO AUMÍNIO E TRATADO COM CÁCIO. Tecnologia em Metalurgia Materiais e Mineração, v. 8, p , KIRICHENCO, Júlio C. B. ; BIEEFEDT, Wagner V. ; VIEA, Antônio Cezar Faria. ESTUDO EXPERIMENTA E TERMODINÂMICO DE INCUSÕES DE ÓXIDOS EM AÇO RESSUFURADO ACAMADO AO AUMINIO. In: 42 Seminário de Aciaria - Internacional, 2011, Salvador - Bahia. 42 Seminário de Aciaria - Internacional, BETRAMI, J. ; BIEEFEDT, Wagner V. ; KIRICHENCO, Júlio C. B. ; VIEA, Antônio Cezar Faria. ESTUDO DA FORMAÇÃO DE INCUSÕES NÃO-METÁICAS EM AÇO RESSUFURADO ACAMADO AO AUMÍNIO. In: 66º Congresso da ABM - Internacional, 2010, São Paulo., 2011, São Paulo. 66º Congresso da ABM - Internacional, 2010, São Paulo., BUZIN, P. J. W. K. ; HECK, N. C. ; SCHNEIDER, I.A.H. ; TUBINO, R. ; VIEA, A.,C.,F. Study of Carbothermic reduction of self-reducing briquettes of EAF dust and iron scale for use in electric steelmaking. In: 66ºCongresso Anual da ABM Internacional, 2011, São Paulo. Anais do 66ºCongresso Anual da ABM Internacional. São Paulo : ABM, p HECK, N. C. ; KUG, J.. ; VIEA, A.,C.,F. Thermodynamic evaluation of the slags of the CaO-SiO2- CROX-MGO system at 1873K. In: 66ºCongresso Anual da ABM Internacional, 2011, São Paulo. Anais do 66ºCongresso Anual da ABM Internacional. São PAulo : ABM, p

18 UFRGS - Publications IENDO, M. A. ; HIDAGO, G.E.N. ; HECK, N. C. ; SAMPAIO, C. H.. Synthesis of zerovalent iron particles for acid mine drainage reactive barriers: experimental study and thermodynamic evaluation. In: Congresso Anual da ABM Internacional, 2011, São Paulo. 66o Congresso Anual da ABM Internacional. São Paulo : ABM, BUZIN, P. J. W. K. ; HECK, N. C. ; SCHNEIDER, I.A.H.. Metal recovery from scrap of printed circuit board manufacture by self-reactive systems. In: Congresso Anual da ABM Internacional, 2011, São Paulo. 66o Congresso Anual da ABM Internacional. São Paulo : ABM, AVES, C.R.R. ; IHA, B.B. ; HECK, N. C. ; SCHNEIDER, I.A.H.. Elaboração de uma liga ferro-cromo alto carbono empregando resíduos industriais do estado do Rio Grande do Sul. In: XXIV Encontro Nacional de Tratamento de Minérios e Metalurgia Extrativa - ENTMME, 2011, Salvador. Anais do XXIV Encontro Nacional de Tratamento de Minérios e Metalurgia Extrativa. Salvador : UFBA, HECK, N. C.. Thermodynamic evaluation on Si transfer from injected pulverized coal to iron in the blast furnace. In: III Congresso Brasileiro de Carvão Mineral III CBCM, 2011, Gramado. Anais do III Congresso Brasileiro de Carvão Mineral, v. B8. AVES, C.R.R. ; IHA, B.B. ; BUZIN, P. J. W. K. ; HECK, N. C. ; SCHNEIDER, I.A.H.. Utilization of ashes from the leather shaving incineration as a source of chromium for the production of HC-FeCr alloy. In: Sustainability through Resource Conservation and Recycling, SRCR 11, 2011, Falmouth. Proceedings of Sustainability through Resource Conservation and Recycling, SRCR 11. Falmouth : MEI, 2011.

19 USIMINAS- Ipatinga Steelmill MG, Brazil Grupo de Redução (Reduction) Blast furnace slag calculations Cálculos Termoquímicos de Escória de Altos Fornos Estudo de P&D em desenvolvimento - Centro de Tecnologia Usiminas - Unidade Ipatinga Waleska Effegen de Oliveira Grupo de Tecnologia da Fabricação do Aço: (Steelmaking) adle furnace slag development Acerto da Composição Química de Escórias de Panela Visando impidez e Dessulfuração do Aço - Estudo de P&D em desenvolvimento - Centro de Tecnologia Usiminas - Unidade Ipatinga Amilton Carlos Cardoso Pinheiro Filho Converter slag development for de-p Ajuste de Escória de Refino Primário Visando Desfosforação do Aço - Estudo de P&D em desenvolvimento - Centro de Tecnologia Usiminas - Unidade Ipatinga Hugo Filipe Parreiras Gonçalves Model for Peritetic reaction control Desenvolvimento de um Modelo para a Previsão da Ocorrência da Reação Peritética Durante a Solidificação dos Aços - Estudo de P&D em desenvolvimento - Centro de Tecnologia Usiminas - Unidade Ipatinga eonardo José Silva de Oliveira

20 UFF Volta Redonda RJ Research staff: Prof. André uiz V. da Costa e Silva Prof Flavio Ferreira, Prof Thales Research areas: Steelmaking process modeling: refractory slag -metal interactions. Non-metallic inclusion formation in steel. Microstructural evolution in steels. Slag viscosity modeling coupled with thermodynamic models Highlights Computational Thermodynamics Course at some Brazilian Industries and Universities. Annual short course for UFF undergraduates. Prof André awarded the Merit Diploma for relevant services in Engineering from the Regional Engineering and Architecture Council of the State of Rio de Janeiro CREA-RJ (Engineering Board) Industry interaction for teaching, on-site learning,motivation of students.

21 UFF Publications -examples W.E. de Oliveira, B.F. Gandra,.A.M. Scudeller, COSTA E SIVA, A. ESTUDO TERMODINÂMICO DE ESCÓRIAS PRIMÁRIAS E FINAIS DE ATO-FORNO UTIIZANDO THERMO-CAC In: 41º Seminário de Redução de Minério de Ferro e Matérias-primas e 12º Seminário Brasileiro de Minério de Ferro, 2011, Vila Velha, ES. Anais do 41º Seminário de Redução de Minério de Ferro e Matérias-primas e 12º Seminário Brasileiro de Minério de Ferro. São Paulo: ABM Brasil, p DIAS, F. M. S., COSTA E SIVA, A., FONSECA, F. A. V., CAMPOS, M. F. CONTRIBUIÇÃO AO DESENVOVIMENTO DO AÇO IF GAVANIZADO, DA CASSE EDDQ, COM TEOR DE CARBONO SUPER UTRA BAIXO E ESTABIIZADO AO TITÂNIO1 In: 65 Congresso ABM Internacional, 2010, Rio de Janeiro.Anais do 65 Congresso ABM Internacional. São Paulo: ABM, p B N STOCO, MARTINS, Antônio Augusto de Rezende, COSTA E SIVA, A. ESTIMATIVA DE VISCOSIDADE EM ESCÓRIAS: APICAÇÃO NO SISTEMA CaO-Al2O3-MgO-SiO2 In: 65 Congresso ABM Internacional, 2010, Rio de Janeiro. Anais do 65 Congresso ABM Internacional. São Paulo: ABM, p MURARI, F. D., COSTA E SIVA, A., AVIEZ, Roberto Ribeiro de ESTUDO DA FORMAÇÃO DA AUSTENITA EM AÇOS MUTIFÁSICOS In: 65 Congresso ABM Internacional, 2010, Rio de Janeiro. Anais do 65 Congresso ABM Internacional. São Paulo: ABM, p MAGAHAES, H.. G., COSTA E SIVA, A., C A da Silva, SIVA, I. A., TORRES, A. ESTUDO TEÓRICO E EXPERIMENTA DE FATORES QUE AFETAM A IMPIDEZ INCUSIONÁRIA DE UM AÇO SAE 1045 In: 65 Congresso ABM Internacional, 2010, Rio de Janeiro. Anais do 65 Congresso ABM Internacional. São Paulo: ABM, p

22 UFF publication examples 1. MURARI, F. D., COSTA E SIVA, A., AVIEZ, Roberto Ribeiro de Effect of Boron on the Microstructure and Mechanical Properties of Cold Rolled Multiphase Steels In: X CAPHAD - Computer coupling of Phase Diagrams and Thermochemistry, 2011, Rio de Janeiro.Program and Abstracts- X CAPHAD. Sao Paulo SP: ABM, AGE, M. G., COSTA E SIVA, A. Evaluating segregation in HSA steels using computational thermodynamics In: X CAPHAD Computer Coupling of Phase Diagrams and Thermochemistry, 2011, Rio de Janeiro. Program and Abstracts- X CAPHAD. São Paulo: ABM, MAGAHAES, H.. G., C A da Silva, Costa e Silva, A Improve cleanliness of SAE 1045 Al-killed steel grade with applied in the automotive industry, In: X CAPHAD- Computer coupling of Phase Diagrams and Thermochemistry, 2011, Rio de Janeiro. Program and Abstracts- X CAPHAD. São Paulo: ABM, COSTA E SIVA, A., CUNHA, M. A., VIEIRA,.N., ASSUNÇÃO, Fernando Cosme Rizzo The Thermodynamics of Aluminum Nitride Precipitation in Steels Revisited In: X CAPHAD- Computer coupling of Phase Diagrams and Thermochemistry, 2011, Rio de Janeiro. Program and Abstracts- X CAPHAD. São Paulo: ABM, COSTA E SIVA, A., BRACARENSE, A.Q., PESSOA, E.C.P., MONTEIRO, M., AVIEZ, Roberto Ribeiro de, ASSUNÇÃO, Fernando Cosme Rizzo, SANTOS, V.R. Thermodynamics of flux behavior in steel welding with focus on hydrogen in steel In: X CAPHAD- Computer coupling of Phase Diagams and Thermochemistry, 2011, Rio de Janeiro. Program and Abstracts- X CAPHAD. São Paulo: ABM, 2011.

23 UFRJ Federal University of Rio de Janeiro Main researcher Prof Dilson Silva dos Santos Themes Alloy 718 processing for Nuclear Applications (PhD research) eonardo Sales Araujo Evaluation of pseudo-binary systems, calculation of phase fractions. Solidification modeling (Scheil) Comparison with experimental determination (EDS). aves phase compostion. Evaluation of the effect of Nb content and the delta phase solvus line. Corrosion and microstructure of Alloy 718 (PhD research) ena de Castro Menezes Estimation of delta phase as a function of cooling rate and chemical composition, in special Nb content. Development of an alloy for hydrogen storage (PhD research) Alejandro David Martinez Thermodynamic studies (including binary, pseudo-binaries and ternary diagrams) of the systems Ti-Cr-V e Ti-Cr-Nb. Evaluation of effects of cooling rate. Processing of Alloy X750 for springs MSc research) Gabriela Regina Xavier Phase diagram, constitution diagrams and phase fraction variation wrt to chemical composition and temperature for the alloy.

24 UFRJ Federal University of Rio de Janeiro Hydrogen embrittlement in hyper-duplex stainless steels Felipe Salvio Hydrogen embrittlement in super-duplex stainless steels Bruno Raphael de Souza Analysis of hydrogen permeation in Alloy 625 Gustavo Brandolin

25 USP São Paulo Research staff: Prof. Hélio Goldenstein Main activities: Magnetic materials Co-Sm Publication at X CAPHAD in cooperation with UFF Oxides (Al-Mn-Ti-O) Publications (CAPHAD 2010 and CAPHAD 2011) Precipitation during aging heat treatment of in Inconel 718 Publication at X CAPHAD in cooperation with UFF Precipitates in 12%Cr stainless steels. Modelling of the thermodynamics and kinetics of austenite eutectoid decomposition. 25

26 USP- CVM Research staff Cláudio G. Schön (coordenador) Helana M. Petrilli and Pablo Guillermo Gonzales-Ormeño (senior researchers) Bruno Geoffroy Scuracchio and Ney Sodré (researchers). Main areas of research Ab initio calculation of phase diagrams (CVM - FP-APW), Application of computational thermodynamics to steel processing. Fe-Mo-Al (ab initio) Fe-Rh-Ti (CVM assessment) Fe-Cr-C (industrial application)

27 EE-USP (formerly FAENQUI)- orena, SP

28 EE-USP (formerly FAENQUI)- orena, SP

29 EE-USP (formerly FAENQUI)- orena, SP

30 Villares Metals S/A APDIC 2011 Report Specialty Steels and Alloys R&D New alloys, alloy and process development. Researchers Celso Antonio Barbosa- R&D Technology R&D Director Alexandre Bellegard Farina, MsC José Britti Bacalhau, MSc Alexandre Sokolowski, MSc Eduardo Netto de Souza, PhD Roberto Tibúrcio Frota, MSc Mario Mantovani, PhD

31 Work in Progress APDIC 2011 Report Researcher : Alexandre Bellegard Farina, MSc Development of new valve alloys and Ni-based alloys using thermodynamic simulations with Thermo-Calc software coupled with TCFE6 and TTNI8 thermodynamic databases. Researcher: José Britti Bacalhau, MsC Development of new tool steels and high speed steels using thermodynamic simulations with Thermo-Calc software coupled with TCFE6 thermodynamic database. Researcher: Alexandre Sokolowski, MSc : Development of a new stainless steels using thermodynamic simulations with Thermo-Calc software and TCFE6 thermodynamic database.

32 Work in Progress APDIC 2011 Report Researcher: Eduardo Netto de Souza, PhD: Simulations of the solidification process with dedicated software coupled with thermodynamic data extracted from Thermo-Calc software using TCFE6 and TTNI8 thermodynamic databases. Definition of parameters for continuous casting process using data from thermodynamic simulations with Thermo-Calc software coupled with SAG and TCFE6 database. Researcher: Mario Mantovani, PhD Thermodynamic modeling of slag/metal reactions for non-metallic inclusions control and process optimization using Thermo-Calc software coupled with TCFE6, SAG and TTNI8 thermodynamic databases. Relevant paper published in the Iron & Steel Technology magazine about the interaction study beteween tundish refractories and the steel in continuous casting. Researcher: Roberto Tibúrcio Frota, MSc: Thermo mechanical modeling of rolling and forging process of alloys with dedicated software coupled with thermodynamic simulations of alloys using Thermo-Calc software and TCFE6 and TTNI8 thermodynamic databases.

33 Interaction between molten steel and different kinds of MgO based tundish linings M. C. Mantovani;. R. Moraes Jr; R. eandro da Silva; E. F. Cabral; E. A. Possente; C. A. Barbosa; B. P. Ramos, Ironmaking & Steelmaking (ISSN: ), Appeared or available online: 15 May 2012 DOI: / Y

34 Published Papers Evolution 18 Number of Published Papers International National