Cilt 11, Sayı 2 (2021)

A case study on the updates of Turkish rapid visual screening methods for reinforced-concrete buildings

2019-01-01T00:00:00Z

A case study on the updates of Turkish rapid visual screening methods for reinforced-concrete buildings Işık, Ercan; Ulu, Ali Emre; Aydın, M. Cihan The changes in rapid seismic assessment methods that can be used to determine the regional earthquake risk distribution of buildings have become inevitable, with the Turkish Building Earthquake Code and Turkish Earthquake Hazard Map which updated in 2018, Within the scope of this study, risk prioritization was made according to the last two regulations for ten different settlements that located in the same earthquake zone in the previous earthquake map. With the current regulation, it has once again emerged that site-specific based analysis and evaluations are necessary. While the building performance scores in the previous regulation were the same for all provinces since they were located in the same earthquake zone, different values were obtained for the provinces with the current regulation. As the PGA value increased, the design spectral acceleration coefficient increased and the building's performance score was lower. This increases the risk in these regions.

Trace element geochemistry of Bitlis ignimbrites sourced by Quaternary Nemrut Volcano: inferences for A2-type magma generation in Eastern Anatolia post-collisional extensional setting

2021-01-01T00:00:00Z

Trace element geochemistry of Bitlis ignimbrites sourced by Quaternary Nemrut Volcano: inferences for A2-type magma generation in Eastern Anatolia post-collisional extensional setting ÇOBAN, Hakan; KALKAN, Özcan Ali In the study presented here, we investigated the whole-rock K-Ar dating and petrological significance of trace element compositions Bitlis (Eastern Anatolia) ignimbrites associated with explosive activities of the well-known Quaternary Nemrut volcano. Considering the previous age determinations (40.9 ka – 264.1 ka) of ignimbrites sourced in Nemrut volcano, and because they contain lithic clasts, obtained whole-rock K-Ar age of Bitlis ignimbrite flow deposits suggest that they are younger than late Pleistocene (< 790 ka), and occurred as the first products of pre-caldera stages of Nemrut stratovolcano. Bitlis trachydacitic ignimbrites with shoshonitic affinity are characterized by the typical negative anomalies of Eu, Nb-Ta, and Ti in chondrite-normalized spider and multi-element variation diagrams, and plot in the fields of within-plate and post-collisional tectonic setting in Rb vs Y+Nb discrimination diagram. Accordingly, similar to that of Nemrut volcanic products, trace element signatures (e.g., high Nb, Ce, Y, and Zr contents) of Bitlis ignimbrites show coincidence with geochemical characteristics of A2-type silicic magmas. Relative to the upper crust, higher La/Ba and Nb/La, and lower Ba/Ta and La/Ta ratios of Bitlis ignimbrites, which are close to that of Nemrut basalts previously reported as the most recent volcanic products, suggest an interaction between OIB-like basaltic magma and upper crust. Our results point to A2-type silicic magma generation in Eastern Anatolia post-collisional extensional setting, and Nemrut lava and pyroclastic rocks (e.g., Bitlis ignimbrites) formed by partial melting of upper crustal rocks at shallow level via interaction with OIB-like basaltic magma derived from a common mantle source.

Study on crystallization process of SiO2 based SiO2-Li2O nano-wire glass ceramic: A molecular dynamics simulation based on SCC-DFTB calculations

2021-01-01T00:00:00Z

Study on crystallization process of SiO2 based SiO2-Li2O nano-wire glass ceramic: A molecular dynamics simulation based on SCC-DFTB calculations CELIK, Fatih Ahmet The aim of this study was to investigate the crystallization behavior of nano-wire SiO2-Li2O glass ceramic (GC) during the slow cooling process by using density functional theory (DFT). For this purpose, the extended tight-binding with self-consistent charge (SCC-DFTB) was used to investigate the geometric optimization and molecular dynamics (MD) process for model system. The structural development was analysed by radial distribution function (RDF) at determined temperatures. The results show that the system tends to crystallization at lower temperatures and transforms from liquid phase to crystal phase with a slow cooling rate.

The Possible External Factor Effecting On NO2 Molecule During Lightning Flash Under Corona Discharge

2021-01-01T00:00:00Z

The Possible External Factor Effecting On NO2 Molecule During Lightning Flash Under Corona Discharge KARABULUT, Ezman The focus in this study is on the formation of the NO2 molecule on the O+NO system, which is the atomdiatom reaction that occurs the most according to the molecular concentrations formed as a result of lightning flashes. In this study, it was mentioned that another external effect that affects NO2 molecule concentrations, other than temperature and visible electromagnetic radiation, is the electric field. This will suppress the formation of O2 at high temperatures and the formation of NO concentration at low temperature, as it increases the barrier in the product channel on the reaction pathway and NO+O recombination in the reactant channel under favorable conditions. Under these two conditions, the NO2 population might be supported by electric field