• Title/Summary/Keyword: Istanbul

Search Result 513, Processing Time 0.028 seconds

Effective lengths of braced frame columns

  • Girgin, Konuralp;Ozmen, Gunay
    • Structural Engineering and Mechanics
    • /
    • v.28 no.2
    • /
    • pp.189-206
    • /
    • 2008
  • In several design codes and specifications, simplified formulae and charts are given for determining the effective lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of braced frames is developed. The procedure utilises a fictitious load analysis of frames and yields errors less than 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range.

Behavior of damaged and undamaged concrete strengthened by carbon fiber composite sheets

  • Ilki, Alper;Kumbasar, Nahit
    • Structural Engineering and Mechanics
    • /
    • v.13 no.1
    • /
    • pp.75-90
    • /
    • 2002
  • Many existing concrete structures suffer from low quality of concrete and inadequate confinement reinforcement. These deficiencies cause low strength and ductility. Wrapping concrete by carbon fiber reinforced polymer (CFRP) composite sheets enhances compressive strength and deformability. In this study, the effects of the thickness of the CFRP composite wraps on the behavior of concrete are investigated experimentally. Both monotonic and repeated compressive loads are considered during the tests, which are carried out on strengthened undamaged specimens, as well as the specimens, which were tested and damaged priorly and strengthened after repairing. The experimental data shows that, external confinement of concrete by CFRP composite sheets improves both compressive strength and deformability of concrete significantly as a function of the thickness of the CFRP composite wraps around concrete. Empirical equations are also proposed for compressive strength and ultimate axial deformation of FRP composite wrapped concrete. Test results available in the literature, as well as the experimental results presented in this paper, are compared with the analytical results predicted by the proposed equations.

Buckling lengths of unbraced multi-storey frame columns

  • Ozmen, Gunay;Girgin, Konuralp
    • Structural Engineering and Mechanics
    • /
    • v.19 no.1
    • /
    • pp.55-71
    • /
    • 2005
  • In several design codes and specifications, simplified formulae and diagrams are given for determining the buckling lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of multi-storey frames is developed. The procedure utilises lateral load analysis of frames and yields errors in the order of 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range and on the safe side.

Effects of Metformin on Cell Kinetic Parameters of MCF-7 Breast Cancer Cells in Vitro

  • Topcul, Mehmet;Cetin, Idil
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.16 no.6
    • /
    • pp.2351-2354
    • /
    • 2015
  • In this study, the antiproliferative effects of the metformin was evaluated on MCF-7 Cells (human breast adenocarcinoma cell line). For this purpose cell kinetic parameters including cell proliferation assay, mitotic index and labelling index analysis were used. $30{\mu}M$, $65{\mu}M$ and $130{\mu}M$ Metformin doses were applied to cells for 24, 48 and 72 hours. The results showed that there was a significant decrease in cell proliferation, mitotic index and labelling index for all experimental groups (p<0.05) for all applications.

FINITE GROUPS WHOSE INTERSECTION GRAPHS ARE PLANAR

  • Kayacan, Selcuk;Yaraneri, Ergun
    • Journal of the Korean Mathematical Society
    • /
    • v.52 no.1
    • /
    • pp.81-96
    • /
    • 2015
  • The intersection graph of a group G is an undirected graph without loops and multiple edges defined as follows: the vertex set is the set of all proper non-trivial subgroups of G, and there is an edge between two distinct vertices H and K if and only if $H{\cap}K{\neq}1$ where 1 denotes the trivial subgroup of G. In this paper we characterize all finite groups whose intersection graphs are planar. Our methods are elementary. Among the graphs similar to the intersection graphs, we may count the subgroup lattice and the subgroup graph of a group, each of whose planarity was already considered before in [2, 10, 11, 12].

Cultural Aspect of Conflict Behaviour in Construction -A Case Study from Turkey

  • Babaoglu, F.Fusun Ertan;Giritli, Heyecan
    • Journal of Construction Engineering and Project Management
    • /
    • v.7 no.2
    • /
    • pp.45-53
    • /
    • 2017
  • Although much research has been conducted to identify the influence of culture on conflict management and resolution behaviours in organizational settings, no study has been done yet in the construction industry particularly in considering the influence of individual level individualistic and collectivistic values. Despite the key role of self-construal in explaining or predicting behaviour in interpersonal conflict, it has not received enough attention in construction management. Reflecting this necessity, the objective of this exploratory study was to establish, through the application of the Rahim Organizational Inventory (ROC II) instrument, how the cultural values of professionals of construction businesses relate to the application of different conflict-handling styles through self-construal. Data were collected using questionnaire surveys from construction professionals working in contracting firms. The findings illustrate the importance of self-construal type as an individual-level cultural variable in explaining the differences in the style of handling interpersonal conflict in the context of the construction industry.

Free vibration analysis of Reissner plates by mixed finite element

  • Eratli, Nihal;Akoz, A. Yalcin
    • Structural Engineering and Mechanics
    • /
    • v.13 no.3
    • /
    • pp.277-298
    • /
    • 2002
  • In this study, free vibration analysis of Reissner plates on Pasternak foundation is carried out by mixed finite element method based on the G$\hat{a}$teaux differential. New boundary conditions are established for plates on Pasternak foundation. This method is developed and applied to numerous problems by Ak$\ddot{o}$z and his co-workers. In dynamic analysis, the problem reduces to the solution of a standard eigenvalue problem and the mixed element is based upon a consistent mass matrix formulation. The element has four nodes and bending and torsional moments, transverse shear forces, rotations and displacements are the basic unknowns. The element performance is assessed by comparison with numerical examples known from literature. Validity limits of Kirchhoff plate theory is tested by dynamic analysis. Shear locking effects are tested as far as $h/2a=10^{-6}$ and it is observed that REC32 is free from shear locking.

Direct determination of influence lines and surfaces by F.E.M.

  • Orakdogen, Engin;Girgin, Konuralp
    • Structural Engineering and Mechanics
    • /
    • v.20 no.3
    • /
    • pp.279-292
    • /
    • 2005
  • In this study, element loading matrices are defined for static application of classical M$\ddot{u}$ller-Breslau principle to finite element method. The loading matrices are derived from existing element matrices using Betti's law and known governing equations of F.E.M. Thus, the ordinates of influence lines and influence surfaces may be easily obtained from structural analysis for the loading matrices derived from governing equations, instead of through introduced unit force or displacement techniques. An algorithm for a computer program and comparative numerical examples are also presented to illustrate the procedure for determination of influence line and surface ordinates.

The Synthesis and Characterization of Some Novel Thioethers: Thio-Subsituted [3]Cumulenes, -1-Buten-3-ynes and Buta-1,3-dienes

  • Ibis, Cemil;Sahin, Aysecik
    • Bulletin of the Korean Chemical Society
    • /
    • v.31 no.8
    • /
    • pp.2255-2260
    • /
    • 2010
  • In this study, some novel thiosubstituted butenyne (3a-d, 7b, 15b), butadiene (4a-b, 4d, 5a, 5c, 6b, 8e, 9c, 10b, 16b, 18e) and [3]cumulene (11a-b with isomer 3a-b, 12a with isomer 13a, 14b, 17e) compounds were synthesized from the reaction of 2H-pentachloro-1,3-butadiene with thiols. The new compounds were characterized by elemental analysis, mass spectrometry, UV-vis, IR, 1H NMR, NMR ($^{13}C$ or APT) spectroscopy.

The Ottoman Palace School Enderun and the Man with Multiple Talents, Matrak$\c{c}{\i}$ Nasuh

  • Corlu, M. Sencer;Burlbaw, Lynn M.;Capraro, Robert M.;Corlu, M. Ali;Han, Sun-Young
    • Research in Mathematical Education
    • /
    • v.14 no.1
    • /
    • pp.19-31
    • /
    • 2010
  • Introduced in this paper is one of the most remarkable Ottoman institutions, the Ottoman Palace School-Enderun, with a focus on the life story of Matrak$\c{c}{\i}$ Nasuh, one of its most noted graduates and teachers. Matrak$\c{c}{\i}$ Nasuh's life and work as a prominent mathematician and a teacher of mathematics are investigated as a case study. It shows how young boys and girls were selected because of their academic potential, brought to Istanbul, and educated in Enderun to serve the Empire. This research articulates the mathematics education on the first institutionalized gifted education system of the world and discusses its implications for today.