Yazarlar
Yayınlar
- MakaleYalnız künye2016Non-destructive testing of an ancient Masonry Bastion
Altunişik, Ahmet Can; Adanur, Süleyman; Genç, Ali Fuat; Günaydin, Murat; Okur, Fatih Yesevi
Historical masonry structures have seismic vulnerability and most damages and demolishes arise from the seismic actions like earthquakes. In this paper, the structural behavior of Zağanos Bastion is examined with experimental and numerical methods. The operational modal analysis technique is used to illustrate the dynamic characteristics of the bastion experimentally. Finite element model is developed by ANSYS software and dynamic characteristics of the bastion, such as natural frequencies and mode shapes are calculated numerically. Furthermore, time history seismic analysis is carried out. The results show that the ambient vibration measurements are enough to identify the structural response of the bastion. Maximum differences between the natural frequencies are attained as 26%. To minimize these differences, finite element model of the bastion should be updated by using some uncertain parameters. The principal stresses are satisfied in general, but the maximum tensile and compression stresses values exceed the allowable code limits at some points of the masonry components.
- MakaleYalnız künye2014New thiophene-1,2,4-triazole-5(3)-ones: Highly bioactive thiosemicarbazides, structures of Schiff bases and triazole-thiols
Ünver, Yasemin; Sancak, Kemal; Çelik, Fatih; Birinci, Emrah; Küçük, Murat; Soylu, Serkan; Burnaz, Nesibe Arslan
Key compound 2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4- tiazole-1-yl) acetohydrazide (3) was synthesized by reacting hydrazine hydrate with ethyl-2-(4-amino-5-oxo-3-(thiophene-2-ylmethyl)-4,5-dihydro-1,2,4-tiazole- 1yl)acetate (2), obtained in basic media from 4-amino-5-(thiophene-2-ylmethyl)- 2H-1,2,4-triazole-3(4H)-one (1). Compound 3 was converted to thiosemicarbazide derivatives (4a-d) and Schiff base derivatives 6a-e and 7a-e. The treatment of compound 4 with NaOH gave 4-amino-2-((4-(4-aryl)-5-mercapto-4H-1,2,4-triazole-3- yl)methyl)-5-(thiophene-2-ylmethyl)-2H-1,2,4-triazole-3(4H)-ones (5a-d). All newly compounds, well characterized by elemental analyses, IR, 1H NMR, 13C NMR and mass spectral studies were tested for their antioxidant and antimicrobial activities. Thiosemicarbazide derivatives (4a-d) were highly active in two antioxidant tests with 69.0-88.2% DPPH scavenging and 503-1257 μM TEAC values, while the others showed lower or no activity. The results of the two antioxidant tests correlated well. Moreover, Thiosemicarbazide derivatives (4a-d) also showed antibacterial activity against Staphylococcus aureus, Bacillus cereus, and Mycobacterium smegmatis. Thiosemicarbazide group deserves attention in the synthesis of bioactive compounds.
- MakaleYalnız künye1998Growth rates of early Campanian rudists in a siliciclastic-calcareous setting (Pontid MTS., North-Central Turkey)
Steuber, Thomas; Yilmaz, Cemil; Löser, Hannes
Rudist communities that developed on the southern slope of the Pontid magmatic arc during the late Cretaceous thrived in a tectonically unstable setting, and in environments that were strongly influenced by siliciclastic sedimentation. Strontium isotope stratigraphy indicates an early Campanian age of the investigated association at Höbek Tepe, near Amasya. Stable isotope analyses of sclerochronological profiles of several shells of the three dominating hippuritid species yielded cyclic variations of δ18O that delineate seasonal variations in palaeotemperature. This allowed for the determination of individual life spans, skeletal growth rates and the reconstruction of the living growth fabric. Annual vertical shell growth of 35-40 mm was maintained by cylindrical morphotypes of Vaccinites ultimus during several successive years, while adult annual shell accretion of conical morphotypes was only 27 to 30 mm. Vertical growth of the co-occurring Yvaniella alpani was considerably slower and rarely exceeded 10mm/year. Differential growth rates of the two most abundant species, and morphological characters of Yvaniella which indicate that skeletal growth capacity was similar to sediment accumulation, allowed for a consistent reconstruction of the original growth fabric. CaCO3 production of the rudist communities amounted to 20 kg x year-1 x m-2 and contributed significantly to the sedimentary budget. Large-scale formation of fine-grained calcareous sediments by bioeroders occurred only in environments of less rapid burial, indicated by associations of slowly-growing geniculate rudist morphotypes and patellate corals. The implications of these results for the distribution of rudists and corals in Cretaceous shallow-marine environments are discussed.
- DergiEuropean Journal of Medicinal Chemistry
- DergiJournal of Cultural Heritage
- DergiGeobios