In Vitro Antimicrobial, Antioxidant, and Antispasmodic Activities and the Composition of the Essential Oil of Origanum acutidens (Hand.-Mazz.) Ietswaart

Ismihan Goze,Ahmet Alim,Senay Akkus Cetinus,Ali Cetin,Nedim Durmus,Ahmet Turan Atas,Nilufer Vural 한국식품영양과학회 2010 Journal of medicinal food Vol.13 No.3

The radical scavenging, antimicrobial, and antispasmodic activities and the composition of Origanum acutidens (Hand.-Mazz.) Ietswaart (Order Labiatte) essential oil were evaluated in vitro. Gas chromatography/mass spectrometry analysis of the oil resulted in the identification of 20 compounds, representing 93.61% of the oil; carvacrol (65%) was the main component. The sample was also subjected to a screening for antioxidant activity by using the 1,1-diphenyl-2-picrylhydrazyl and β-carotene/linoleic acid assays. The essential oil exhibited strong antioxidant activity. Using the agar disk diffusion method, antimicrobial activities of the essential oils were determined for nine microorganisms; antimicrobial activity was shown against eight of them. O. acutidens oil exhibited spontaneous contractions in rat ileum at the 100% level at 0.1mg/mL level.

Investigation of linear and nonlinear of behaviours of reinforced concrete cantilever retaining walls according to the earthquake loads considering soil-structures interactions

Gursoy, Senol,Durmus, Ahmet Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.1

It is known that retaining walls were severely damaged as well in the most recent earthquakes having occurred in the countries in the active seismic belts of the world. This damage can be ascribed to the calculation methods used for the designs of retaining walls in the event of their constructions and employment having been accurately carried out. Generally simplified pseudo-static methods are used in the analysis of retaining walls with analytical methods and soil-structure interaction are not considered. In view of these circumstances, in this article by taking soil interaction into consideration, linear and nonlinear behaviours of retaining walls are analyzed with the assistance of LUSAS which is one of the structural analysis programs. This investigations are carried out per LUSAS which employs the finite element method as to the Erzincan (1992) Earthquake North-South component and the obtained findings are compared with the ones obtained from the method suggested in Eurocode-8, which is still effective today, and Mononobe-Okabe method. Not only do the obtained results indicate the distribution and magnitude of soil pressures are depend on the filling soil but on the foundation soil as well and nonlinear effects should be considered in designs of these walls.

Investigation of linear and nonlinear of behaviours of reinforced concrete cantilever retaining walls according to the earthquake loads considering soil-structures interactions

Senol Gürsoy,Ahmet Durmus 국제구조공학회 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.1

It is known that retaining walls were severely damaged as well in the most recent earthquakes having occurred in the countries in the active seismic belts of the world. This damage can be ascribed to the calculation methods used for the designs of retaining walls in the event of their constructions and employment having been accurately carried out. Generally simplified pseudo-static methods are used in the analysis of retaining walls with analytical methods and soil-structure interaction are not considered. In view of these circumstances, in this article by taking soil interaction into consideration, linear and nonlinear behaviours of retaining walls are analyzed with the assistance of LUSAS which is one of the structural analysis programs. This investigations are carried out per LUSAS which employs the finite element method as to the Erzincan (1992) Earthquake North-South component and the obtained findings are compared with the ones obtained from the method suggested in Eurocode-8, which is still effective today, and Mononobe-Okabe method. Not only do the obtained results indicate the distribution and magnitude of soil pressures are depend on the filling soil but on the foundation soil as well and nonlinear effects should be considered in designs of these walls.

Modal parameter identification of in-filled RC frames with low strength concrete using ambient vibration

Arslan, Mehmet E.,Durmus, Ahmet Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.50 No.2

In this study, modal parameters such as natural frequencies, mode shapes and damping ratios of RC frames with low strength are determined for different construction stages using ambient vibration test. For this purpose full scaled, one bay and one story RC frames are produced and tested for plane, brick in-filled and brick in-filled with plaster conditions. Measurement time, frequency span and effective mode number are determined by considering similar studies and literature. To obtain experimental dynamic characteristics, Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification techniques are used together. It is shown that the ambient vibration measurements are enough to identify the most significant modes of RC frames. The results indicate that modal parameters change significantly depending on the construction stages. In addition, Infill walls increase stiffness and change the mode shapes of the RC frame. There is a good agreement between mode shapes obtained from brick in-filled and in-filled with plaster conditions. However, some differences are seen in plane frame, like expected. Dynamic characteristics should be verified using finite element analysis. Finally, inconsistency between experimental and analytical dynamic characteristics should be minimize by finite element model updating using some uncertain parameters such as material properties, boundary condition and section properties to reflect the current behavior of the RC frames.

Optimum cost design of RC columns using artificial bee colony algorithm

Hasan Tahsin Ozturk,Ahmet Durmus 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.5

Optimum cost design of columns subjected to axial force and uniaxial bending moment is presented in this paper. In the formulation of the optimum design problem, the height and width of the column, diameter and number of reinforcement bars are treated as design variables. The design constraints are implemented according to ACI 318-08 and studies in the literature. The objective function is taken as the cost of unit length of the column consisting the cost of concrete, steel, and shuttering. The solution of the design problem is obtained using the artificial bee colony algorithm which is one of the recent additions to metaheuristic techniques. The Artificial Bee Colony Algorithm is imitated the foraging behaviors of bee swarms. In application of this algorithm to the constraint problem, Deb's constraint handling method is used. Obtained results showed that the optimum value of numerical example is nearly same with the existing values in the literature.

Optimum cost design of RC columns using artificial bee colony algorithm

Ozturk, Hasan Tahsin,Durmus, Ahmet Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.5

Optimum cost design of columns subjected to axial force and uniaxial bending moment is presented in this paper. In the formulation of the optimum design problem, the height and width of the column, diameter and number of reinforcement bars are treated as design variables. The design constraints are implemented according to ACI 318-08 and studies in the literature. The objective function is taken as the cost of unit length of the column consisting the cost of concrete, steel, and shuttering. The solution of the design problem is obtained using the artificial bee colony algorithm which is one of the recent additions to metaheuristic techniques. The Artificial Bee Colony Algorithm is imitated the foraging behaviors of bee swarms. In application of this algorithm to the constraint problem, Deb's constraint handling method is used. Obtained results showed that the optimum value of numerical example is nearly same with the existing values in the literature.

Seismic Assessment of a Historical Masonry Mosque by Experimental Tests and Finite Element Analyses

Ferit Cakir,Burcin S. Seker,Ahmet Durmus,Adem Dogangun,Habib Uysal 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.1

The mosques are the most important pieces of Islamic culture in terms of their architectural and structural properties. Although,thousands of these mosques are still being used all over the world, many historical mosques are at risk in terms of seismic events. This study mainly focuses on historical Lala Pasha Mosque, which is located in the city center of Erzurum, Turkey. The main purposeof this study is to assess the structural behaviors and to investigate the architectural features and components of the mosque. Thestudy was carried out in two main steps. Firstly, compression and three-point bending tests on the construction materials wereconducted to determine the mechanical properties of the materials. In the second step, a three-dimensional finite element model of themosque was developed and structural responses for the model were investigated by means of static and dynamic analyses. The resultsof the analyses show that the most critical parts of the mosque are the dome, pulley, and the supports of the main arch structures thatcarry the main dome. Additionally, the dynamic analyses prove that the most critical parts of the mosque are the sub-sections of themain columns, the window edges, and small domes.

Optimum design of RC shallow tunnels in earthquake zones using artificial bee colony and genetic algorithms

Hasan Tahsin Öztürk,Erdem Turkeli,Ahmet Durmus 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.17 No.4

The main purpose of this study is to perform optimum cost design of cut and cover RC shallow tunnels using Artificial bee colony and genetic algorithms. For this purpose, mathematical expressions of objective function, design variables and constraints for the design of cut and cover RC shallow tunnels were determined. By using these expressions, optimum cost design of the Trabzon Kalekapısı junction underpass tunnel was carried out by using the cited algorithms. The results obtained from the algorithms were compared with the results obtained from traditional design and remarkable saving from the cost of the tunnel was achieved.