Βιβλίο

“Σερβοκινητήρια Συστήματα (Επαγωγικοί κινητήρες και σύγχρονοι κινητήρες μόνιμου μαγνήτη)”, Εκδόσεις ΤΖΙΟΛΑ, σελίδες 567, Θεσσαλονίκη 2010.

Σημειώσεις για τα Μαθήματα

“Μαγνητικά Κυκλώματα Ηλεκτρικών Μηχανών & Ηλεκτρομηχανική Μετατροπή Ενέργειας”, Σημειώσεις για το μάθημα Ηλεκτρικές Μηχανές Α΄, σελίδες 88, Θεσσαλονίκη 2005.

“Μονοφασικοί Κινητήρες”, Σημειώσεις για το μάθημα Ηλεκτρικές Μηχανές Β΄, σελίδες 50, Θεσσαλονίκη 2004.

Διδακτορική Διατριβή 

“Ελαχιστοποίηση απωλειών των σύγχρονων κινητήρων και μελέτη της λειτουργικής και θερμικής των συμπεριφοράς”. Α.Π.Θ., σελίδες 164, Θεσσαλονίκη 1997.

 

Δημοσιεύσεις σε διεθνή περιοδικά με κρίση

[J-1]    C. Mademlis, J. Xypteras, and N. Margaris “Loss Minimization in Wound-Field Cylindrical Rotor Synchronous Motor Drives”. IEEE Trans. on Power Electronics, vol. 13, no. 2, pp. 288 – 296, March 1998.

[J-2]    C. Mademlis, J. Xypteras, and N. Margaris “Loss Minimization in Surface Permanent Magnet Synchronous Motor Drives”. IEEE Trans. on Industrial Electronics, vol. 47, no. 1, pp. 115-122, Feb. 2000.

[J-3]    C. Mademlis, N. Margaris, and J. Xypteras J. “Magnetic and Thermal Performance of a Synchronous Motor under Loss Minimization Control”. IEEE Trans. on Energy Conversion, vol. 15, no. 2, pp. 135-142, June 2000.

[J-4]    C. Mademlis and V.G. Agelidis, “On Considering Magnetic Saturation with Maximum Torque to Current Control in Interior Permanent Magnet Synchronous Motor Drives”, IEEE Trans. on Energy Conversion, vol.16, no. 3, pp. 246-252, Sept. 2001.

[J-5]    V.G. Agelidis and C. Mademlis, “Technology of Offshore Wind Turbines and Farms and Novel Multilevel Converter-Based HVDC Systems for their Grid Connections”, Wind Engineering, vol. 26, no. 6, pp. 383-395, Nov. 2002, (Invited paper).

[J-6]    C. Mademlis and N. Margaris, “Loss Minimization in Vector Controlled Interior Permanent Magnet Synchronous Motor Drives”, IEEE Trans. on Industrial Electronics, vol. 49, no. 6, pp. 1344-1347, Dec. 2002.

[J-7]    C. Mademlis, “Compensation of Magnetic Saturation in Maximum Torque to Current Vector Controlled Synchronous Reluctance Motor Drives”, IEEE Trans. on Energy Conversion, vol. 18, no. 3, pp. 379-385, Sept. 2003.

[J-8]    I. Kioskeridis and C. Mademlis, “Energy Efficiency Optimization in Synchronous Reluctance Motor Drives”, IEE Proc. – Electric Power Applications, vol. 150, no. 2, pp. 201-209, March 2003.

[J-9]    C. Mademlis and I. Kioskeridis, “Performance Optimization in Switched Reluctance Motor Drives with On-line Commutation Angle Control”, IEEE Trans. on Energy Conversion, vol. 18, no. 3, pp. 448-457, Sept. 2003.

[J-10]  C. Mademlis, I. Kioskeridis, and N. Margaris, “Optimal Efficiency Control Strategy for Interior Permanent Magnet Synchronous Motor Drives”, IEEE Trans. on Energy Conversion, vol. 19, no. 4, pp. 715-723, Dec. 2004.

[J-11]  C. Mademlis, I. Kioskeridis, and Theodoulidis T., “Optimization of Single-Phase Induction Motors, Part I: Maximum Energy Efficiency Control”, IEEE Transon Energy Conversion, vol. 20, no. 1, pp. 187-195, March 2005.

[J-12]  C. Mademlis, Theodoulidis T., and I. Kioskeridis, “Optimization of Single-Phase Induction Motors, Part II: Magnetic and Torque Performance under Optimal Control”, IEEE Trans. on Energy Conversion, vol. 20, no. 1, pp. 196-203, March 2005.

[J-13]  C. Mademlis and I. Kioskeridis, “Optimizing Performance in Current Controlled Switched Reluctance Generators”, IEEE Trans. on Energy Conversion, vol. 20, no. 3, pp. 556-565, Sept. 2005.

[J-14]  I. Kioskeridis and C. Mademlis, “Maximum Efficiency in Single-Pulse Controlled Switched Reluctance Motor Drives”, IEEE Trans. on Energy Conversion, vol. 20, no. 4, pp. 809-817, Dec. 2005.

[J-15]  I. Kioskeridis and C. Mademlis, “Optimal Efficiency Control of Switched Reluctance Generators”, IEEE Trans. on Power Electronics, vol. 21, no. 4, pp. 1062-1072, July 2006.

[J-16]  I. Kioskeridis and C. Mademlis, “A Unified Approach for Four-Quadrant Optimal Controlled Switched Reluctance Machine Drives with Smooth Transition between Control Operations”, IEEE Trans. on Power Electronics, vol. 24, no. 1, pp. 301-306, Jan. 2009.

[J-17]  C. Mademlis and I. Kioskeridis, “Gain Scheduling Regulator for High Performance Position Control of Switched Reluctance Motor Drives”, IEEE Trans. on Industrial Electronics, vol. 57, no. 9, pp. 2922-2931, Sept. 2010.

[J-18]  A. Mesemanolis, C. Mademlis, and I. Kioskeridis, “High-Efficiency Control for a Wind Energy Conversion System with Induction Generator”, IEEE Trans. on Energy Conversion, 2012, vol. 27, no. 4, pp. 958-967, Dec. 2012.

[J-19]  A. Mesemanolis, C. Mademlis, and I. Kioskeridis, “Optimal Efficiency Control Strategy in Wind Energy Conversion System with Induction Generator”, IEEE Trans on Power Electronics, Journal of Emerging and Selected Topics in Power Electronics, vol. 1, no. 4, pp. 238-246, Dec. 2013.

[J-20]  N. Jabbour and C. Mademlis, “Improved Control Strategy of a Supercapacitor-Based Energy Recovery System for Elevator Applications”, IEEE Trans. on Power Electronics, vol. 31, no. 12, pp. 8398-8408, Dec. 2016.

[J-21]  N. Karakasis, A. Mesemanolis, T. Nalmpantis, and C. Mademlis, “Active Yaw Control in a Horizontal Axis Wind System without Requiring Wind Direction Measurement”, IET Renewable Power Generation, vol. 10, no. 6, pp. 1441-1449, Oct. 2016.

[J-22]  N. Jabbour, and C. Mademlis, ‘Supercapacitor-Based Energy Recovery System with Improved Power Control and Energy Management for Elevator Applications”, IEEE Transactions on Power Electronics, vol. 32, no. 12, pp. 9389-9399, Dec. 2017.

[J-23]  N. Karakasis and C. Mademlis, ‘High Efficiency Control Strategy in a Wind Energy Conversion System with Doubly Fed Induction Generator”, Renewable Energy, Elsevier, (125), pp. 974-984, March 2018.

[J-24]  N. Karakasis, E. Tsioumas, N. Jabbour, A. Bazzi, and C. Mademlis, “Optimal efficiency control in a wind system with doubly fed induction generator”, IEEE Transactions on Power Electronics, vol. 34, no. 1, pp. 356-368, Jan. 2019.

[J-25]  N. Jabbour and C. Mademlis, “Online Parameters Estimation and Auto-Tuning of a Discrete-Time Model Predictive Speed Controller for Induction Motor Drives”, IEEE Transactions on Power Electronics, vol. 34, no. 2, pp. 1548-1559, Feb. 2019.

[J-26]  M. Koseoglou, E. Tsioumas, N. Jabbour and C. Mademlis, “Highly Effective Cell Equalization in a Lithium-Ion Battery Management System”, IEEE Transactions on Power Electronics, (accepted for publication, Early Access 2019).

[J-27]  E. Tsioumas, N. Jabbour, M. Koseoglou, and C. Mademlis, “A Novel Control Strategy for Improving the Performance of a Nearly Zero Energy Building”, IEEE Trans. on Power Electronics, vol. 35, no. 2, pp. 1513-1524, Feb. 2020.

[J-28]  N. Jabbour, E. Tsioumas, C. Mademlis, and E. Solomin, “A Highly Effective Fault-Ride-Through Strategy for a Wind Energy Conversion System with Doubly Fed Induction Generator”, IEEE Trans. on Power Electronics, vol. 35, no. 8, pp. 8154-8164, Aug. 2020.

Ανακοινώσεις σε συνέδρια με κρίση

[C-1]    C. Mademlis, J. Xypteras, and N. Margaris “Loss Minimization in Synchronous Motors”, Proceedings of IEEE International Symposium of Industrial Electronics, ISIE’95, vol. 1, pp. 297-302, Athens, 1995.

[C-2]    C. Mademlis, J. Xypteras, and N. Margaris “Calculation and Minimization of Synchronous Motor Power Losses”, Workshop in Contemporary Problems in Power Engineering, pp. 153-168, Thessaloniki 1995.

[C-3]                C. Mademlis, J. Xypteras, and N. Margaris “Magnetic and Thermal Analysis of a Wound-Field Cylindrical Rotor Synchronous Motor in Optimal Efficiency Operation” Intern. Conf. on Electrical Machines, ICEM’98, vol. 1, pp. 187-192, Istanbul 1998.

[C-4]   C. Mademlis and V. Agelidis, “A High-Performance Vector Controlled Interior PM Synchronous Motor Drive with Extended Speed Range Capability”, 27th Annual Conference of IEEE Industrial Electronics Society, IECON’01, Colorado, pp. 1475-1482, Nov. 2001.

[C-5]    C. Mademlis and I. Kioskeridis, “Optimal Control in Switched Reluctance Motor Drives” IEE International Conference MedPower’02, Athens, Greece, Nov. 2002.

[C-6]    C. Mademlis and V. Agelidis, “Wide Speed Operation of Synchronous Reluctance Motor Drives with a High-Performance Current Regulation Control Scheme” IEE Intern. Conf. MedPower 2002, Athens, Greece, Nov. 2002.

[C-7]    V. Agelidis and C. Mademlis, “Offshore Wind Turbines, Associated Drive Technology and Novel Multilevel Converter-Based HVDC Grid Connections” IEE Intern. Conf. MedPower 2002, Athens, Greece, Nov. 2002.

[C-8]    T. Theodoulidis and C. Mademlis, “Study on Efficiency Improvement of Single-Phase Induction Motors”, 38th International Univ. Power Eng. Conference, UPEC 2003, vol. 1, pp. 45-48, Thessaloniki, Greece, Sept. 2003.

[C-9]    C. Mademlis and A. Michaelides, “Magnetic Performance of a Single Phase Induction Motor under Triac-based Voltage Control”, 8th WSEAS Trans. on Circuits and Systems, International Conference, vol. 3, no. 5, pp. 1240-1245, Athens, Greece, July 2004.

[C-10]  N. Margaris, C. Mademlis, and I. Kioskeridis, “Improved control techniques for variable speed electric motor drives”, Workshop in Power Electronics, Electric Motion Systems and Industrial Applications, Technical Chamber of Greece, Athens, April 2006.

[C-11]  C. Mademlis and I. Kioskeridis, “Calculation of the Optimal Fire Angles in Single-Pulse Controlled Switched Reluctance Generator Drives”, Intern. Conf.on Electrical Machines, ICEM 2006, Chania, Greece, Sept. 2006.

[C-12]  A. M. Michaelides and C. Mademlis, “Dynamic Performance Analysis on Switched Reluctance Motors and Iron Loss Calculation using the Finite Element Method”, Intern. Conf. on Electrical Machines, ICEM 2006, Chania, Greece, Sept. 2006.

[C-13]  C. Mademlis and I. Kioskeridis, “Smooth Transition between Optimal Control Modes in Switched Reluctance Motoring and Generating Operation”, Intern. Confon Power Systems Transients, IPST 2007, Lyon, France, June 2007.

[C-14]  C. Mademlis and I. Kioskeridis, “High Performance Position Control for Switched Reluctance Motor Drives with the Average Torque Control Method” Intern. ConfCEFC 2008, Athens, Greece, pp. 179, May 2008.

[C-15]  C. Mademlis and I. Kioskeridis, “Four-Quadrant Smooth Torque Controlled Switched Reluctance Machine Drives”, Intern. ConfPESC 2008, Rhodos, Greece, pp. 1216-1222, June 2008.

[C-16]  Papadopoulos K. G., C. Mademlis, Michaelides A. M., Riley C. P., and Coenen I., “Advanced Parametric Environment for Electrical Machines Design Optimization”, Intern. ConfICEM 2008, Vilamoura, Portugal, Sept. 2008.

[C-17]  C. Mademlis and I. Kioskeridis, “A Fine-Tuning Regulator for High Performance Control of Switched Reluctance Motor Drives”, Intern. ConfMedPower 2008, Thessaloniki, Greece, Nov. 2008.

[C-18]  C. Mademlis and I. Kioskeridis, “Position Control of Switched Reluctance Motors by using an Online Fine-Tuning Regulator”, Intern. ConfElectromotion 2009, Lily, France, July 2009.

[C-19]  C. Mademlis and I. Kioskeridis, “Control Design for Maximum Efficiency of a Variable Speed Wind Energy Conversion System”, Intern. ConfDISTRES 2009, Nicosia, Cyprus, Dec. 2009.

[C-20]  A. Mesemanolis, C. Mademlis, I. Kioskeridis, “Maximum Efficiency of a Wind Energy Conversion System with a PM Synchronous Generator”, Intern. ConfMedPower 2010, Agia Napa, Cyprus, Nov. 2010.

[C-21]  A. Mesemanolis, M. Mitrosilis, and C. Mademlis, “Complete system for measurements and testing of electric machines”, 4th Metrology National Conference, Athens, Feb. 2012.

[C-22]  A. Mesemanolis, C. Mademlis, I. Kioskeridis, “Maximum Electrical Energy Production of a Variable Speed Wind Energy Conversion System”, 21th IEEE Intern. Symp. Industrial Electronics ISIE 2012, Hangzhou, China, May 2012.

[C-23]  N. Karakasis, A. Mesemanolis and C. Mademlis, “Performance Study of Start-up Control Techniques in a Wind Energy Conversion System with Induction Generator”, Intern. Conf. Speedam 2012, Sorrento, Italy, June 2012.

[C-24]  A. Mesemanolis, C. Mademlis, I. Kioskeridis, “A Fuzzy-Logic Based Control Strategy for Maximum Efficiency of a Wind Energy Conversion System”, Intern. Conf. Speedam 2012, Sorrento, Italy, June 2012.

[C-25]  N. Karakasis, A. Mesemanolis and C. Mademlis, “Wind Turbine Simulator for Laboratory Testing of a Wind Energy Conversion Drive Train”, Intern. Conf. MedPower 2012, Cagliari, Italy, Sept. 2012.

[C-26]  A. Mesemanolis and C. Mademlis, “A Neural Network Based MPPT Controller for Variable Speed Wind Energy Conversion Systems”, Intern. Conf. MedPower 2012, Cagliari, Italy, Sept. 2012.

[C-27]  A. Mesemanolis and C. Mademlis, “On-line estimation of induction generator parameters using adaptive neuro-fuzzy inference systems for wind energy conversion systems”, Intern. Conf. Renewable Energies and Power Quality ICREPQ 2013, Bilbao, Spain, March 2013.

[C-28]  A. Mesemanolis, C. Mademlis, and I. Kioskeridis, “Wind Speed Sensorless Maximum Efficiency Control for Wind Energy Conversion Systems”, Intern. Conf. WindPower AWEA 2013, Chicago, USA, May 2013.

[C-29]  A. Mesemanolis and C. Mademlis, “Self-Tuning Maximum Power Point Tracking Control for Wind Generation Systems”, Inter. Conf. Clean Electrical Power, ICCEP 2013, Alghero, Italy, June 2013.

[C-30]  A. Mesemanolis, C. Mademlis, and I. Kioskeridis, “Copper Loss Minimization in Combination with MPPT Control in a Wind Energy Conversion System with Induction Generator”, Inter. Conf. Clean Electrical Power, ICCEP 2013, Alghero, Italy, June 2013.

[C-31]  N. Jabbour, C. Mademlis, and I. Kioskeridis, “Improved Performance in a Supercapacitor-Based Energy Storage Control System with Bidirectional DC-DC Converter for Elevator Motor Drives”, Intern. Conf. IET 7th Power Electronics, machines and DrivesPEMD 2014, Manchester, UK, April 2014.

[C-32]  Karakasis, N., C. Mademlis, and I. Kioskeridis, “Improved Start-up Procedure of a Stand-Alone Wind System with Doubly-Fed Induction Generator”, Intern. Conf. IET 7th Power Electronics, machines and DrivesPEMD 2014, Manchester, UK, April 2014.

[C-33]  Mesemanolis, A., C. Mademlis, and I. Kioskeridis, “Neuro-Fuzzy Energy Management System in Elevator Drive Applications for Maximum Braking Energy Regenerative Capability”, Intern Conf. IET 7th Power Electronics, machines and DrivesPEMD’2014, Manchester, UK, April 2014.

[C-34]  A. Mesemanolis and C. Mademlis, “Combined Maximum Power Point and Yaw Control Strategy for a Horizontal Axis Wind Turbine”, ΙΕΕΕ Intern. Conf. Electrical MachinesICEM’2014, Berlin, Germany, Sept. 2014.

[C-35]  N. Karakasis, A. Mesemanolis, C. Mademlis, and I. Kioskeridis, “Efficiency increase of a low power wind system with squirrel cage induction generator”, 10th Conference on Renewable Energy Sources, Thessaloniki, Nov. 2014.

[C-36]  C. Mademlis“Influence of the Measurement Accuracy of Wind Sensors on Wind System Performance”, ΙΕΕΕ Intern. Conf. Clean Electrical Power, ICCEP 2015, Taormina, Italy, June 2015.

[C-37]  E. Tsioumas, N. Karakasis, N. Jabbour, and C. Mademlis, “Energy Management and Power Control Strategy at the Low Wind Speed Region of a Wind Generation Microgrid”, IEEE Intern. Conf. IECON’2016, Firenze, Italy, Oct. 2016.

[C-38]  N. Karakasis, N. Jabbour, E. Tsioumas, and C. Mademlis, “Efficiency Increase in a Wind System with Doubly Fed Induction Generator”, IEEE Intern. Conf. IECON’2016, Firenze, Italy, Oct. 2016.

[C-39]  N. Jabbour, E. Tsioumas, N. Karakasis, and C. Mademlis, “Discrete-Time Model Predictive Control for High Performance Speed Control in an Induction Motor Drive”, IEEE Intern. Conf. IECON’2016, Firenze, Italy, Oct. 2016.

[C-40]  N. Jabbour, E. Tsioumas, N. Karakasis, and C. Mademlis, “Improved Monitoring and Battery Equalizer Control Scheme for Electric Vehicle Applications”, 11th IEEE Intern. Symp. on Diagnostics for Electric Machines, Power Electronics & Drives, SDEMPED 2017.

[C-41]  E. Tsioumas, N. Karakasis, N. Jabbour, C. Mademlis, “Indirect Estimation of the Yaw-Angle Misalignment in a Horizontal Axis Wind Turbine”, 11th IEEE Intern. Symposium on Diagnostics for Electric Machines, Power Electronics and Drives, SDEMPED 2017.

[C-42]  W. Chen, E. Hotchkiss, C. Mademlis, and A.M. Bazzi, “Integrated Fault Diagnosis and Recovery in NPC Multilevel Inverters”, 11th IEEE Intern. Symposium on Diagnostics for Electric Machines, Power Electronics and Drives, SDEMPED 2017, Tinos, Greece.

[C-43]  E. Tsioumas, N. Jabbour, and C. Mademlis, “Estimation of the Battery Health by Monitoring the Electric Motor Drive Performance in a Building Application”, IEEE Int. Conf. ICEM’2018, Alexandroupoli, Greece.

[C-44]  C. Mademlis, “A Holistic Approach for Increasing the Electric Energy Efficiency of a Nearly Zero Energy Building”, IEEE Int. Conf. EFEA’2018, Rome, Italy.

[C-45]  N. Jabbour, E. Tsioumas, M. Koseoglou, and C. Mademlis, “Highly Reliable Monitoring and Equalization in a Hybrid Energy Storage System with Batteries and Supercapacitors for Electrical Motor Drives in Building Applications”, IEEE Int. Conf. SPEC’2018, Singapore.

[C-46]  M. Koseoglou, E. Tsioumas, N. Jabbour, and C. Mademlis, “An Improved Active Li-ion Battery Equalization Scheme for Enhancing the Performance of a nearly Zero Energy Building and Electric Vehicle Microgrid”, IEEE Int. Conf. SPEC’2018, Singapore.

[C-47]  E. Tsioumas, N. Jabbour, M. Koseoglou, E. Sfetkos, and C. Mademlis, “Enhanced Effectiveness in the Appliance Scheduling and Energy Storage Control by utilizing the Particle Swarm Technique for a Nearly Zero Energy Building”, IEEE Int. Conf. SPEC’2018, Singapore.

[C-48]  D. Papagiannis, E. Tsioumas, N. Jabbour, M. Koseoglou, and C. Mademlis, “Fault |Tolerance in an Active Suspension System with a Linear Permanent Magnet Actuator for Automotive Applications”, IEEE Int. Conf. WEMDCD’2019, Athens, Greece.

[C-49]  N. Jabbour, E. Tsioumas, D. Papagiannis, M. Koseoglou, and C. Mademlis, “An Integrated Energy Management System for Nearly zero Energy Buildings”, IEEE Int. Conf. ICCEP’2019, Otranto, Puglia-Italy.

[C-50]  N. Jabbour, E. Tsioumas, M. Koseoglou, D. Papagiannis, and C. Mademlis, “Comprehensive Model of a Nearly Zero Energy Building that can be Used as Basis for an Effective Energy Management System”, IEEE Int. Conf. ICCEP’2019, Otranto, Puglia-Italy.

[C-51]  C. Mademlis, “Increase of the Energy Efficiency of an Urban Type Wind Turbine in a Smart Energy Building”, IEEE Int. Conf. ETRAN’2019, Silver Lake, Servia.

[C-52]  D. Papagiannis, M. Kosseoglou, E. Tsioumas, N. Jabbour, A. Karlis, C. Mademlis, and E. Solomin, “Improved fault-ride-through control scheme without requiring fault-detection system for a doubly fed induction generator in a wind system”, in Proc. IEEE Int. Conf. ICEM’2020, Aug. 2020, Gothenburg, Sweden.

[C-53]  N. Jabbour, E. Tsioumas, M. Koseoglou, D. Papagiannis, and C. Mademlis, “A novel methodology for converting a conventional building to a nearly zero energy building”, in Proc. IEEE Int. ICSGCE’2020, Oct. 2020, Malaysia.

[C-54]  M. Koseoglou, E. Tsioumas, N. Jabbour, D. Papagiannis, and C. Mademlis, “An effective power hardware-in-the-loop system for the simulation testing of an energy management system of a nearly zero energy building microgrid”, in Proc. IEEE Int. Conf. ICSGCE’2020, Oct. 2020, Malaysia.

[C-55]  E. Tsioumas, D. Papagiannis, M. Koseoglou, N. Jabbour, and C. Mademlis, “An effective methodology for the optimal sizing of the renewable energy sources and energy storage system in a nearly zero energy building”, in Proc. IEEE Int. Conf. ICSGCE’2020, Oct. 2020, Malaysia.

[C-56]  D. Papagiannis, N. Jabbour, E. Tsioumas, M. Koseoglou, and C. Mademlis, “Estimation of the consumed electric energy by the unschedulable loads in a nearly zero energy building”, in Proc. IEEE Int. Conf. ICSGCE’2020, Oct. 2020, Malaysia.

[C-57]  C. Mademlis, N. Jabbour, and E. Tsioumas, “Estimation of the Battery Capacity in the Microgrid of a Nearly Zero Energy Building According to the Desired Degree of Energy Autonomy”, in Proc. ΙΕΕΕ Int. Conf. PCIM-Asia’2020, Nov. 2020, Shanghai, China.

[C-58]  A. Karlis, A. Kladas, C. Mademlis, E. Mitronikas, J. Prousalidis, and E. Strangas, “More electric ship initiative: Customized solutions advantages”, Marine Technology 2020 Annual Meeting, Athens, Greece.