Contributed talks and abstracts

2003
  1. Hiroshi Taiko, Cagin Tahir, Daisuke Kawakami, W. A. Goddard III, "Computational simulation for dynamical deformation of amorphous poly(ethylene terephthalate) by uniaxial elongation," ACS Meeting, Apr 2004.
  2. " Elastic and Plastic Behavior in Nanoscale Materials," MRS Fall 2003.
  3. " Polarizable Charge Equilibration Force Field and Application to Phase Transformation in Ferroelectrics," MRS Fall 2003.
  4. " Modeling of Thermophysical Properties and Phase Diagrams of Multicomponent Metallic Alloys," MRS Fall 2003.
  5. " Effect of monomeric sequence of Nafion on its nanostructure and transport properties," MRS Fall 2003.
  6. " Molecular dynamics study of water and sugar dynamics in supercooled mixtures," Valeria Molinero, Tahir Cagin, William A Goddard, APS March 2003.
  7. " Coarse Grain Modeling of Polysaccharides," Valeria Molinero, Tahir Cagin, William A Goddard, APS March 2003.
  8. " Molecular Modeling of Nanostructure and Water Transport in Nafion," S.S. Jang, V. Molinero, T. Cagin, W. A. Goddard, III, APS March 2003
  9. " INFULENCE OF CORE ON ITS PRPERTIES FOR THE 1/2a<111> SCREW DISLOCATION IN BCC Ta," G. F. Wang, A. Strachan, T. Cagin, W. A. Goddard, III, MRS April 2003.
  10. "THEORETICAL AND COMPUTATIONAL INVESTIGATION OF DEVELOPMENT OF A CROSSBAR SWNT ASSEMBLY." Siping Han, T. Cagin ,W.A. Goddard, MRS, April 2003.
  11. " Multiscale Simulations of Ferroelectric Polymers," Haibin Su, Alejandro Strachan, Alberto Cutinio, Tahir Cagin, William A. Goddard, III, Penn State, 2003.
  12. " Computational approaches to thermal conductivity in nanoscale devices, " T. Cagin, J. Che, W. A. Goddard, III, MRS 2003.
2002
  1. "Ab Initio Studies On Phase Behavior of Barium Titanate," Mustafa Uludogan, Tahir Cagin, William A. Goddard, III, MRS 2002.
  2. "Plastic deformation and failure from First Principles," Alejandro Strachan, Tahir Cagin, and William A. Goddard, III, CECAM 2002.
2001
  1. M. S. Diallo, A. Strachan, T. Cagin and W. A. Goddard III, Bulk Thermodynamic and Structural Properties of Petroleum Geomacromolecules from Atomistic Simulations 1. Arabian Light Asphaltenes
  2. Guofeng Wang, Alejandro Strachan, Tahir Cagin, William A. Goddard III "Atomistic Simulation of kinks for 1/2a<111> Screw Dislocation in Ta," MRS Spring Meeting March 2001, San Francisco.
  3. G.S. Hwang, E. Heifets, T. Cagin, W.A. Goddard, Y. Sato, M. Miyata, M. Uehara, "Simulation of Boron-Dopant frofile evolution during ultrashallow junction processing of Si," MRS Spring Meeting March 2001, San Francisco.
  4. T. Cagin, et. al. "Multiscale Modeling and Simulation in Nanotribology: Methods and Applications," May 2001, Orlando, FL.

2000

  1. Cem Ozdogan, Gulay Dereli, Tahir Cagin, "The Influence of Uniaxial, Radial and Torsional Deformations on the Electronic Properties of Nanotubes: An O(N) TBMD Study", Eighth Foresight Conference on Molecular Nanotechnology, November 3-5, 2000, Bethesda, MD.
  2. Goddard WA, Muller R, Strachan A, Kua J, Faglioni F, Philipp D, Feldmann M, Chakraborty D, Jang YH, Xu X, Blanco M, Tang Y, Cagin T "Tutorial: Case studies in the use of density functional theory for transition metal systems, with an emphasis on heterogeneous and homogeneous catalysis, metal alloys, and transition metal oxides." ACS Summer Meeting, Aug 2000, DC.
  3. G. Aygun, G. Dereli, T. Cagin, "Structure and properties of Liquid Metals from Molecular Dynamics", APS March Meeting, 2000, Minneapolis.
  4. W. A. Goddard, T. Cagin, E. Demiralp, Y, Zhou, E. Heifets, S. Dasgupta, S. Hwang, M. Blanco, B-L. Tsai, Y. Qi, "MSC/Caltech collaborations with industry on materials and Polymer technologies", ACS Spring Meeting, March 2000, San Francisco.
  5. T. Cagin, E. Demiralp, W. A. Goddard, III, "Equation of state and phase behavior of Al2O3", ACS Spring Meeting, March 2000, San Francisco.
  6. W. A. Goddard, T. Cagin, Y. Qi, A. Strachan, G. Wang, "Molecular Dynaimcs simulation of Glasses," ACS Spring Meeting March 2000, SF, CA.
  7. W. A. Goddard, T. Cagin, S. Dasgupta, M. Blanco, R.P. Muller, file1 Modeling and Simulation Applications of Technological Importance at MSC, MRS Spring Meeting April 2000, San Francisco.
  8. T. Cagin, Coarse Grain Dynamics Simulations of Dendrimers, MRS Spring meeting, April 2000, San Francisco.
  9. W. A. Goddard, M. Blanco, T. Cagin, N. Vaidehi, S. Dasgupta, R. Muller, Strategies for multi scale modeling and simulation of organic materials, MRS Spring meeting, April 2000, San Francisco.
  10. William A. Goddard, Tahir Cagin, S. Dasgupta, M. Blanco, N. Vaidehi, and R. Muller, Modeling and simulation of materials for industrial applications ACS 2000 August, Washington DC.
  11. W. A. Goddard, A. Strachan, A. C.T. vanDuin, T. Cagin, J. Che, Y. Qi, D. Chakraborty, S. Dasgupta, "New bond dissociating force fields for describing reactions and phase transitions," ACS 2000 August, Washington DC.
  12. Osamu Kitao, Ersan Demiralp, Jan Sefcik, Tahir Cagin, and William A. Goddard III, Force Field and Hydrophilicity of Aluminophosphaste Zeolite, International Symposium on zeolites and microporous crystals, ZMPC2000.
  13. W. A. Goddard, T. Cagin, A. Strachan, R. P. Muller, First principles multiscale approaches to prediction of mechanical properties of materials, ICTAM 2000, Chicago.
  14. G. F. Wang, A. Strachan, T. Cagin, W. A. Goddard, Atomistic simulations on 1/2<111> screw dislocations in BCC Ta, Washington DC.
  15. Y. Qi, T. Cagin, A. Strachan, W. A. Goddard, Large Scale Atomic Dislocations in Ni, Washington. DC.
  16. William A. Goddard, III, Tahir Cagin, Jianwei Che, Alejandro Strachan, and Yanhua Zhou, First Principles Multiscale Modeling of Physicochemical Aspects of Tribology, Lyon Conference, September 5, 2000.
  17. W. A. Goddard, T. Cagin, G. S. Hwang, J. Che, A. Strachan, "Multiscale modeling (from first principles to continuum) for Electronic and Nanoelectronic Materials," MAPINT 2000, Dayton, OHIO, "Aspects of Electronic and Nanoelectronic Materials Modeling"
  18. G. Wang, A. Strachan, T. Cagin, W. A. Goddard, III "Atomistic view of theoretical strength of bcc metals: core structure and mobility of 1/2a<111> screw dislocation in Ta" MRS 2000 Fall, Boston.
  19. Y. Qi, T. Cagin, W. L. Johnson, W. A. Goddard, III, "Size, Dimensionality And Orientation Dependence Of Melting And Crystallization In Ni Nanostructures," MRS 2000 Fall, Boston.
  20. Yue Qi, Alejandro Strachan, Tahir Cagin, William A. Goddard III, "Screw dislocation core structure, annihilation and cross slip processes in FCC Ni," MRS 2000 Fall, Boston.
  21. Jianwei Che, Tahir Cagin, and William A. Goddard III, "Mechanical Properties of Charged Carbon Nanotube," MRS 2000 Fall, Boston.
  22. H-J Lee, Y. Qi, T. Cagin, A. Strachan, W. A. goddard, W. L. Johnson, "Molecular Dynamics Simulations of Supercooled Liquid Metals and Glasses," MRS 2000 Fall, Boston.
  23. Guofeng Wang, Tahir Cagin, Ryan Martin and William A. Goddard, III "Structures and properties of PAMAM dendrimers up to Generation 12 simulations based on continuous configurational biased direct Monte Carlo and Molecular Dynamics methods," ARO/MURI Meeting, Aberdeen, September 20-22, 2000.
  24. Guofeng Wang, Tahir Cagin, Ryan Martin, William A. Goddard, III, and Virgil Percec, "Structures and properties of Percec-type self-assembling dendrimers based on continuous configurational biased direct Monte Carlo and Molecular Dynamics methods," ARO/MURI Meeting, Aberdeen, September 20-22, 2000.
  25. Tahir Cagin, Nicholas Breen, Gregg Caldwell, William A. Goddard, III, and Steve Zimmermann "Predictions of Structures and binding properties of Zimmermann Cored Dendrimers," ARO/MURI Meeting, Aberdeen, September 20-22, 2000.
  26. Tahir Cagin, Guofeng Wang, William A. Goddard, III, "New approached to Mesoscale simulations of dendrimers with applications to PAMAM, Percec, and Frechet-type systems," ARO/MURI Meeting, Aberdeen, September 20-22, 2000.

1999

  1. William A. Goddard, III and Tahir Cagin, Synthetic Strategies for Nanoscale Devices and Applications
  2. Tahir Cagin, Ryan Martin and W. A. Goddard, III Molecular Modeling of dendrimers for Unimolecular Imprinting
  3. Xinlei Hua, Tahir Cagin, Jianwei Che, and W.A. Goddard III Quantum mechanical studies on formation mechanisms of fullerenes
  4. Jianwei Che, Tahir Cagin, and W. A. Goddard, III, Thermal Conductivity of Carbon Nanotube,
  5. Guanghua Gao, Tahir Cagin, and W.A. Goddard, III, Energetics and Structure of Single Walled Carbon Nanotoroids
  6. X. Hua, J. Che, T. Cagin and W. A. Goddard, DFT and MD studies on formation mechanisms of fullerenes, The First EL.B.A. - Foresight Conference on Nanotechnology, 14-16 April 1999, Rome, Italy.
  7. W. A. Goddard and T. Cagin, New methods for atomistic applications to nanoscale materials and devices The First EL.B.A. - Foresight Conference on Nanotechnology, 14-16 April 1999, Rome, Italy.
  8. W.A. Goddard III, T. Cagin Simulations at the Nanoscale, NanoForum, Zurich, 1999.
  9. W.A. Goddard III, M. Blanco, T. Cagin, J. Sefcik, S. Hwang, Y. Jang, Y. Zhou, "From atomistic simulations to engineering models" ACS March Meeting, Anaheim, 1999.
  10. T. Cagin, A. Strachan, E. Demiralp, W.A. Goddard, III, Phase Diagram of MgO from DFT and MD simulations, APS March 1999, Atlanta.
  11. E. Demiralp, T. Cagin, W. A. Goddard, III, Molecular dynamics Simulations of Alumina, APS March 1999, Atlanta.
  12. G. Dereli, M. Uludogan, M. Tomak, T. Cagin, Alloying behavior of some FCC transition metals, APS March 1999, Atlanta.

1998

  1. Tahir Cagin, Donald A. Tomalia, William A. Goddard, III, "Dynamics of encapsulated zero valent metals within PAMAM Dendrimers" 1998 MRS Fall Meeting Boston
  2. Hao Li, T. Cagin, Y. Kimura, W. A. Goddard, III, "Intermetalic compund Au-Cu: Structure, thermodynamics and mechanical properties," 1998 MRS Fall Meeting Boston
  3. T. Cagin, Y. Qi, H. Li, W. A. Goddard, H. Ikeda, W. L. Johnson, Y. Kimura, "Calculation of thermal, mechanical and transport properties of model glass formers," 1998 MRS Fall Meeting Boston
  4. Y. Qi, H. Ikeda, T. Cagin, W. L. Johnson, W. A. Goddard, "Deformation behavior of crystalline and aorphous metalic nanowires," 1998 MRS Fall Meeting Boston
  5. Jianwei Che, Tahir Cagin, Micheal N. Gardos and William A. Goddard, "Diamond and Polycrystalline Diamond for MEMS Applications: Atomic Level Simulation and Analysis of Experiments on Friction and Wear Processes" 1998 MRS Fall Meeting Boston
  6. Y. Zhou, T. Cagin, W. A. Goddard III, E. S. Yamaguchi, R. Frazier, Y. Tang "Simulation of Thermal Stability and Friction: A lubricant confined between Monolayers of Wear Inhibitors on Iron Oxide." 1998 MRS Fall Meeting Boston
  7. Mamadou S Diallo Tahir Cagin Jean-Loup M Faulon William A Goddard III "Thermodynamic Properties of Asphaltenes: A Predictive Approach Based on Computer Assisted Structure Elucidation and Atomistic Simulations," AIChE Annual Meeting, Miami, FL 1998
  8. Jan Sefcik Ersan Demiralp Tahir Cagin William A. Goddard III "Modeling Oxides with Dynamic Charge Equilibration Method ," AIChE Annual Meeting, Miami, FL 1998
  9. T. Cagin, D. A. Tomalia, W. A. Goddard, Molecular Dynamics Simulation of Dendrimers with Encapsulated Metals, Sixth Molecular Nanotechnology Conference
  10. T. Cagin, J. Che, M. N. Gardos, W. A. Goddard, III, Simulation and Analysis of Experiments on Friction and Wear of Diamond: A material for MEMS and NEMS applications, Sixth Molecular Nanotechnology Conference
  11. J. Che, T. Cagin, W. A. Goddard, III, Studies of fullerenes and Carbon Nanotubes by an extended bond order potential Sixth Molecular Nanotechnology Conference
  12. Stephen P. Walch,William A Goddard III and Tahir Cagin, "Computational Studies of the Interaction of H/H2 with Diamond and Silicon Surfaces," Sixth Molecular Nanotechnology Conference.
  13. W. A. Goddard, E. Demiralp, T. Cagin, S. Hwang, YH Jang, J. Sefcik, "Dynamic Charge Equilibration force field (D-QEq-FF) with applications to phase transitions, surface chemistry, and other properties of inorganic systems." 23-27 August 1998, ACS, Boston.
  14. T. Cagin, "Extended System Molecular Dynamics Methods for Open and Semi- open Systems", 23-27 August 1998, ACS, Boston.
  15. T. Cagin, W. A. Goddard, III, "Synthetic Approaches for Studying Transport Properties of Materials", 23-27 August 1998, ACS, Boston.
  16. E. Demiralp, T. Cagin, N. T. Huff, W.A. Goddard, "New Interaction Potentials for Silica," XVIII International Congress on Glass, San Fransisco, 5-10 July 1998.
  17. N.T. Huff, E. Demiralp, T. Cagin, W. A. Goddard, III, "Factors affecting glass formations in MD Simulations," XVIII International Congress on Glass, San Fransisco, 5-10 July 1998.
  18. T. Cagin, E. Demiralp, W.A. Goddard, III Pressure Induced Phase Transformations of Silica Polymorphs and Glasses APS March Meeting, 16-20 March, Los Angeles.
  19. G. Gao, T. Cagin and W.A. Goddard, III, Structure and Properties of K-doped SWNT APS March Meeting, 16-20 March, Los Angeles.
  20. Y. Qi, T. Cagin, and W. A. Goddard, III, Simulation of Amorphous Metalic Alloy: Ag-Cu APS March Meeting, 16-20 March, Los Angeles.
  21. Y. Zhuo, T. Cagin, W.A. Goddard, III, E. Yamaguchi, R. Fraser, Y.C. Tang, Thermal Stability of SAM Models for Ashless Wear Inhibitors on Iron Oxide APS March Meeting, 16-20 March, Los Angeles.
  22. J. Sefcik, E. Demiralp, T. Cagin, and W. A. Goddard, III Rational Design of Zeolites for Catalysis and Separation APS March Meeting, 16-20 March, Los Angeles.
  23. G. Gao, T. Cagin and W.A. Goddard, III, Energetics, Structure, Mechanical and Vibrational Properties of Single Walled Carbon Nano Tubes APS March Meeting, 16-20 March, Los Angeles.
  24. Lu Sun, Tahir Cagin and W. A. Goddard, III, Molecular Dynamics Simulation of Energetic Materials: Equation of State of TATB APS March Meeting, 16-20 March, Los Angeles.
  25. Ersan Demiralp, Tahir Cagin, and William A. Goddard III, New Interatomic Potentials for Simulation of Oxides APS March Meeting, 16-20 March, Los Angeles.
  26. Osamu Kitao, Ersan Demiralp, Tahir Cagin, and William A. Goddard III, Molecular Dynamics Simulations of AlPO4 APS March Meeting, 16-20 March, Los Angeles.
  27. J.W. Che, G. Gao, T. Cagin, W. A. Goddard, III, Comparative studies on Properties of Carbon Nano tubes and Nano tori APS March Meeting, 16-20 March, Los Angeles.
  28. D. G. Fraser, T. Cagin, E. Demiralp, W. A. Goddard, III, "New transferable interatomic potentials for simulating melting of Mg silicates near the base of mantle," A.G.U. 1998.
1997
  1. "Pressure Induced Phase Transformations in Silica," with Ersan Demiralp and William A. Goddard III, MRS Fall Meeting, Dec. 1-4, 1997.
  2. "MD Studies on Ag, Au, Cu and Au-Cu, Ag-Cu: Thermophysical Properties and Phase Transformations," with Yue Qi, Yoshitaka Kimura, and William A. Goddard, III. MRS Fall Meeting, Dec. 1-4, 1997.
  3. "Molecular Mechanics and Molecular Dynamics Analysis of Drexler-Merkle Gears and Neon Pump," with A. Jaramillo-Botero, G. Gao, and W. A. Goddard, III, Fifth Foresight Conference on Nanotechnology.
  4. "Structure, thermodynamic and mechanical properties of nanotubes," with G. Gao, and W. A. Goddard, III, Fifth Foresight Conference on Nanotechnology.
  5. "Novel Algorithms for Massively Parallel, Long-Term, Simulation of Molecular Dynamics Systems," with Fijany, A. Jaramillo-Botero, S. Gulati and W.A. Goddard, in 4th National Symposium on LARGE-Scale Analysis and Design on High-Performance Computers and Workstations, Williamsburg, VA, 15-17 Oct. 97.
  6. "A Massively Parallel Constrained Force Algorithm for MD Simulation of Polymers and Dendrimers", with A. Fijany, A. Jaramillo-Botero, S. Gulati and W.A. Goddard, International Conference on Computational Physics: PC '97.
  7. "MPSim: A Massively Parallel General Simulation Program for Materials", with M. Iotov, G. Gao, N. Vaidehi and W.A. Goddard, International Conference on Computational Physics: PC '97.
  8. "A Massively Parallel Algorithm for the Solution of Constrained Equations o f Motion with Applications to Large-Scale, Long-Time Molecular Dynamics Simulations" with A. Fijany, T. R. Coley, and W. A. Goddard, American Chemical Society, April 1997.
  9. "A Massively Parallel Algorithm for Solution of Constrained Equations of Motion in Molecular Dynamics", with A. Fijany, A. Jaramillo-Botero, W. A. Goddard, III. American Physical Society, March 1997.
  10. "Properties of fcc Metals from Many Body Potentials", with Y. Kimuara and W. A. Goddard, III. American Physical Society, March 1997.
  11. "Thermal and Mechanical Properties of FCC metals and their binary Alloys" with M. Uludogan, G. Dereli and M. Tomak American Physical Society, March 1997.
  12. "Shear Viscosities of Metals and Alloys from NEMD Simulations" of Motion in Molecular Dynamics", with K.A. Mansour, Y. Qi and W. A. Goddard, III. American Physical Society, March 1997.
  13. "Au-Cu Ordered Intermetallic Compounds: Structure, Thermodynamics and Mechanical Properties", with Y. Kimura, H. Li and Q. A. Goddard, III. American Physical Society, March 1997.
  14. "New Interatomic Potentials For Silicas" with E. Demiralp and W. Goddard III, American Physical Society, March 1997.
  15. Dynamical Simulation of a Possible Hexatic Phase in a 2D Colloidal System with 1/r^3 Interactions," with S. Sen. merican Physical Society, March 1997.
  16. "Viscosity and ordering of linear alkanes under homogeneous shear flow: A NEMD Simulation" with K. A. Mansour and W. A. Goddard, III. Society of Rheology Meeting, Galveston, Texas, February 1997.
1996
  1. "Volumetric and thermal properties of Asphaltenes", with M. Diallo and W. A. Goddard, MRS Meeting, April 1996, San Fransisco.
1993
  1. "Characterization of Polyester Properties by Molecular Simulation Techniques," with P. Qian and Z.M. Chen, ACS Meeting, Chicago, August 1993.
  2. "Characterization of Highly Oriented Polyimides Using Molecular Simulations," with P. Qian and Z.M. Chen, ACS Meeting, Chicago, August 1993.
  3. "Molecular Dynamics Study of RbC24 and O2C24," with B.M. Pettitt and Z.M. Chen, APS Meeting, Seattle, March 1993.
  4. "Molecular Dynamics Study of Polycarbonate," with C.F. Fan, Z.M. Chen, and K. Smith, APS Meeting, Seattle, March 1993.
  5. "New Methods for Atomistic Simulations with Applications to Polymers," with W.A. Goddard, III, Polymer Conference, Cambridge, U.K. September 1993.
1992
  1. "Mechanical Response of High Performance Polymers," MRS Meeting, Boston, November 1992.
  2. "Ionic Overlayers on Corrugated Surfaces: Structure," with S. Sen, H. Seong, and S.D. Mahanti, MRS Meeting, Boston, November 1992.
  3. "Ionic Overlayers on Corrugated Surfaces: Melting," with H. Seong, S.D. Mahanti, S. Sen, MRS Meeting, Boston, November 1992.
  4. "Thermodynamic and Elastic Properties of Polyethylene at Elevated Temperatures," with N. Karasawa, S. Dasgupta, W.A. Goddard, MRS Meeting, San Fransisco, April 1992
  5. "Melting of a Repulsive Screened Coulomb System in 2D - Effect of Corrugation," with H. Seong, S.D. Mahanti, S. Sen, APS Meeting, Indianapolis, March 1992.
  6. "Domains and Domain Walls in Graphite Intercalation Compounds," with H. Seong, S.D. Mahanti, S. Sen, APS Meeting, Indianapolis, March 1992.
1991
  1. "Structural Properties of Stage 2 Alkali Graphite Intercalation Compounds," with S. Sen, and S.D. Mahanti, Midwest Solid State Theory Symposium, 6-7 October 1991
  2. "Modeling Elastic Response of Polymers," Southwest Meeting of ACS, San Antonio, 2-4 October 1991.
  3. "On the Low Temperature Structure of RbC24 Stage 2 Graphite Intercalation Compunds," with S. Sen, and S.D. Mahanti, APS Meeting, Cincinnatti, March 1991.
  4. "Atomistic Simulations of Stiff Chain Heterocyclic Polymers," with. W.A. Goddard, III, APS Meeting, Cincinnatti, March 1991.
1990
  1. "Semiempirical Crystal Orbital Calculations of Band Gaps in Conjugated Polymers," with D.S. Dudis, 7th American Theoretical Chemistry Conference, San Diego, July 1990.
1989
  1. "Chemical Potential from NVE Molecular Dynamics," with B.M. Pettitt, 1989 Spring Meeting of Texas Section of APS, Houston, April 1989.
  2. "Molecular Dynamics Algorithms for the Non-Space Filling Geometries," with B.M. Pettitt, 1989 Spring Meeting of Texas Section of APS, Houston, April 1989.
  3. "Temperature Dependence of Elastic Properties of Nickel," with B.M. Pettitt, APS Meeting, St. Louis, March 1989.
1988
  1. "Higher Order Elastic Constants from Molecular Dynamics," with J.R. Ray, 1988 Annual Meeting of Southeastern Section of APS, November 1988.
  2. "Recrystallization of Sodium: A Molecular Dynamics Study," with J.R. Ray, APS Meeting, New Orleans, March 1988.
1987
  1. "Statistical Mechanics of Isothermal Molecular Dynamics Ensembles," with J.R. Ray, 1987 Annual Meeting of Southeastern Section of APS, November 1987.
  2. "Statistical Mechanics of Molecular Dynamics Ensembles," with J.R. Ray, 1987 Annual Meeting of Southeastern Section of APS, November 1987.
1983
  1. "Homotopy Theoretic Classification of Topologically Stable Defects in Liquid Crystals," with T. Dereli, 1983 Annual Meeting of Turkish Physics Society.