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11. Impaired endothelial function irrespective of systemic inflammation or atherosclerosis in mastocytosis.

Author

Öztop, Nida, Özer, Pelin Karaca, Demir, Semra, Beyaz, Şengül, Tiryaki, Tarık Onur, Özkan, Gülkan, Aydogan, Mehmet, Bugra, Melike Zehra, Çolakoglu, Bahauddin, Büyüköztürk, Suna, Nalçacı, Meliha, Yavuz, Akif Selim, Gelincik, Aslı, Oztop, Nida, Ozer, Pelin Karaca, Beyaz, Sengul, Ozkan, Gulkan, Colakoglu, Bahauddin, Buyukozturk, Suna, and Nalcacı, Meliha

Published
2021
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13. High-velocity impact of large caliber tungsten projectiles on ordinary Portland and calcium aluminate cement based HPSFRC and SIFCON slabs. Part II numerical simulation and validation.

Author

Gülkan, P. and Korucu, H.

Subjects
PORTLAND cement, CALCIUM aluminate, CONCRETE slabs, NUMERICAL analysis, DEFORMATIONS (Mechanics)
Abstract

We present the numerical implementation, simulation, and validation of the high-velocity impact experiments that have been described in the companion article. In this part, numerical investigations and simulations performed to mimic the tests are presented. The experiments were analyzed by the explicit integration-based software ABAQUS for improved simulations. Targets were modeled with a damaged plasticity model for concrete. Computational results of residual velocity and crater dimensions yielded acceptable results. [ABSTRACT FROM AUTHOR]

Published
2011
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14. Reassessment of Probabilistic Seismic Hazard in the Marmara Region. .

Author

Kalkan, Erol, Gülkan, Polat, Yilmaz, Nazan, and Çelebi, Mehmet

Subjects
EARTHQUAKE hazard analysis, EARTHQUAKE prediction, PROBABILITY theory, GEOLOGIC faults, EARTHQUAKES, SHEAR (Mechanics)
Abstract

In 1999, the eastern coastline of the Marmara region (Turkey) witnessed increased seismic activity on the North Anatolian fault (NAF) system with two damaging earthquakes (M 7.4 Kocaeli and M 7.2 Düzce) that occurred almost three months apart. These events have reduced stress on the western segment of the NAF where it continues under the Marmara Sea. The undersea fault segments have been recently explored using bathymetric and reflection surveys. These recent findings helped scientists to understand the seismotectonic environment of the Marmara basin, which has remained a perplexing tectonic domain. On the basis of collected new data, seismic hazard of the Marmara region is reassessed using a probabilistic approach. Two different earthquake source models: (1) the smoothed-gridded seismicity model and (2) fault model and alternate magnitude-frequency relations, Gutenberg-Richter and characteristic, were used with local and imported ground-motion-prediction equations. Regional exposure is computed and quantified on a set of hazard maps that provide peak horizontal ground acceleration (PGA) and spectral acceleration at 0.2 and 1.0 sec on uniform firm-rock site condition (760 m/sec average shear wave velocity in the upper 30 m). These acceleration levels were computed for ground motions having 2% and 10% probabilities of exceedance in 50 yr, corresponding to return periods of about 2475 and 475 yr, respectively. The maximum PGA computed (at rock site) is 1.59 along the fault segments of the NAF zone extending into the Marmara Sea. The new maps generally show 10% to 15% increase for PGA, 0.2 and 1.0 sec spectral acceleration values across much of Marmara compared to previous regional hazard maps. Hazard curves and smooth design spectra for three site conditions: rock, soil, and soft-soil are provided for the Istanbul metropolitan area as possible tools in future risk estimates. [ABSTRACT FROM AUTHOR]

Published
2009
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15. A critical reevaluation of stresses generated during vertical and lateral condensation of gutta-percha in the root canal.

Author

Telli, Cüneyt, Gülkan, Polat, and Günel, Halis

Subjects
FINITE element method, CUSPIDS, PHYSIOLOGICAL stress, CONDENSATION, GUTTA-percha, DENTAL pulp cavities, ROOT canal treatment
Abstract

The finite element method was used to calculate the stresses in a maxillary canine tooth produced during lateral and vertical condensation. Description of the biological domain to be analyzed, and conversion of the manual operations of the endodontist to realistic load representation are intricate problems which must be overcome before stresses are recovered and plotted. The stresses in dentin are in general of comparable magnitudes during lateral or vertical condensation, but these magnitudes generally remain much below those presented in a previous study. From these calculations it appears that root fractures reported by some investigators may be explained in terms of stress concentrations and local irregularities of the samples tested. [ABSTRACT FROM AUTHOR]

Published
1994
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17. The European-Mediterranean Distributed Accelerometric Data-Base

Author

Xavier Goula, Carlos Augusto Fernandes de Oliveira, C. Pappaioanou, John Clinton, Philippe Guéguen, Teresa Susagna, A. Roca, Can Zulfikar, S. Godey, Catherine Péquegnat, Institut geològic de Catalunya (IGC), Institut Geològic de Catalunya-IGC, Risques, Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), European Mediterranean Seismological Centre (EMSC/CSEM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Ondes et Structures (Isterre), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), Depart Civil Engineering and Architecture (IST), Instituto Superior Técnico, Universidade Técnica de Lisboa (IST), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Institute of Engineering Seismology& Earthquake Engineering (ITSAK), ITSAK, Kandilli Observatory and Earthquake Research Institute (KOERI), Boğaziçi University [Istanbul], financement européen, S. Akkar, P. Gülkan, T. van Eck (Eds.), NERIES, European Project: 34012,NERIES, Risques (Risques), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Centre National de la Recherche Scientifique (CNRS), Ondes et Structures, Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-PRES Université de Grenoble-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Boǧaziçi üniversitesi = Boğaziçi University [Istanbul], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire Central des Ponts et Chaussées (LCPC)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Laboratoire Central des Ponts et Chaussées (LCPC)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Université Joseph Fourier - Grenoble 1 (UJF)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])

Subjects
Ground motion, 021110 strategic, defence & security studies, Engineering, Peak ground acceleration, NERIES, Database, Distributed database, business.industry, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, 0211 other engineering and technologies, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], 02 engineering and technology, 010502 geochemistry & geophysics, computer.software_genre, Base (topology), 01 natural sciences, Set (abstract data type), Data portal, Accelerometric data, business, computer, database, 0105 earth and related environmental sciences
Abstract

International audience; We created an archive for European acceleration data, based on distributed database of accelerogram waveforms, accessed through the new European Earthquake Data Portal (http://www.seismicportal.eu). Data are open to the scientific and engineering community. Currently the 6 core partners contribute data from 1,379 earthquakes with magnitudes ranging from M1.0 to M7.4. Strong Motion Data are available with epicentral distances up to 1,000 km. Additionally, agencies are encouraged to contribute data. Waveforms included in the database are uniformly processed to create a set of engineering parameters that are used to search the database. In addition to the database, we compiled a survey of the existing accelerometric stations in the Euro-Mediterranean region. We expect this platform to be the basis for growing sharing of European Strong Motion Data in an open environment, in as near to real-time as is possible from network operators.

Published
2011
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18. Additional studies on the distribution of stresses during vertical compaction of gutta-percha in the root canal.

Author

Telli C, Gülkan P, and Raab W

Subjects
Computer Simulation, Cuspid, Dental Stress Analysis statistics & numerical data, Finite Element Analysis, Humans, Maxilla, Models, Biological, Root Canal Obturation statistics & numerical data, Dental Stress Analysis methods, Gutta-Percha chemistry, Root Canal Obturation methods
Abstract

Objective: This study was designed to investigate the effect of certain pathological alterations of the dental structures (diminishing bone support, internal resorption, root perforation, periapical lesion) on stress distribution during root canal filling procedures by the warm vertical compaction technique., Design: The computer stress analyses were done for a maxillary canine tooth model which was based on dimensions recovered from a human cadaveric maxilla scanned by CT., Methods: The finite element method was used to calculate the stresses generated during root canal filling procedures by warm vertical compaction technique. Patterns of stress distribution associated with various alterations in dental structures were investigated. For this purpose 60 cases were simulated. The hypothetical force of 10 N is taken as a unit representation. For other magnitudes of applied force, the corresponding stresses would be scaled directly because the calculations were made for linear materials., Results and Conclusion: It is found that, when diminishing bone support and internal resorption are concurrently simulated, a marked increase in stress magnitudes occur (maximum von Mises stress 5.37 N/mm2). However, these values still remain much below the most frequently reported tensile strength of dentine (50-100 N/mm2). If dentist's handwork is transformed into equivalent edge tractions on gutta-percha, then stresses in dentine, even when they are corrected for 3-kg applied force, appear to remain below fracture strengths of this material. This result leads us to conclude that when warm vertical compaction technique is skillfully performed and inadvertent undue force is not applied, a premature root fracture in a large rooted maxillary anterior tooth with straight root canal anatomy is not likely to occur, even for the unfavourable conditions simulated in our model. This result, like all results derived from modelling applications, is of course contingent upon agreement between the way in which the clinical operations are performed and the way in which they are mirrored for computer representation. We believe that the approach described here avoids the spurious stresses that have been reported in similar investigations.

Published
1999
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19. Stress analysis during root canal filling by vertical and lateral condensation procedures: a three-dimensional finite element model of a maxillary canine tooth.

Author

Telli C and Gülkan P

Subjects
Computer Simulation, Dental Pulp Cavity anatomy & histology, Dentin physiopathology, Elasticity, Gutta-Percha, Humans, Maxilla, Stress, Mechanical, Tensile Strength, Tooth Fractures etiology, Cuspid physiopathology, Dental Stress Analysis methods, Models, Biological, Root Canal Obturation adverse effects, Root Canal Obturation methods
Abstract

Objective: To investigate the distribution of stresses that occur in a maxillary canine tooth during vertical and lateral condensation of gutta-percha in the root canal., Design: An elaborate three-dimensional finite element model of a maxillary canine tooth was developed for the purposes of stress analysis. A sample stress analysis was also performed to demonstrate the variations in stress values that occur between different solutions of the same problem., Methods: A 3D finite element analysis was performed on a maxillary canine tooth model which was created using the dimensions of computer tomographic scans of a cadaveric maxilla as reference., Results: If the manual operations of the endodontist are transcribed to the software by considering the finite size of the plugger or the spreader, then the maximum stresses generated in the dentine are much smaller than the reported tensile strength of this material., Conclusion: The causes of the fractures in the dentine reported by previous investigators must be traced to conditions which were not considered in this study. These include aspects of modelling, which is the most important single parameter on which the final results depend. Stresses calculated by means of the complicated 3D model appear to agree with those recovered from a simpler 2D idealisation.

Published
1998
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