UPPER BOUND ON THE THIRD HANKEL DETERMINANT FOR FUNCTIONS DEFINED BY RUSCHEWEYH DERIVATIVE OPERATOR

Yavuz, Tugba Korean Mathematical Society 2018 대한수학회논문집 Vol.33 No.2

Let S denote the class of analytic and univalent functions in the open unit disk $D=\{z:{\mid}z{\mid}<1\}$ with the normalization conditions f(0) = 0 and f'(0) = 1. In the present article, an upper bound for third order Hankel determinant $H_3(1)$ is obtained for a certain subclass of univalent functions generated by Ruscheweyh derivative operator.

A CLASS OF □-RECURRENT ALMOST COSYMPLECTIC SPACE

( Yavuz Selim Balkan ),( Siraj Uddin ),( Ali H. Alkhaldi ) 호남수학회 2018 호남수학학술지 Vol.40 No.2

In this paper, we study '-recurrent almost cosymplectic (k, μ)-space and prove that it is an □-Einstein manifold with constant coefficients. Next, we show that a three-dimensional lo-cally □-recurrent almost cosymplectic (k, μ)-space is the space of constant curvature.

Numerical study of ship motions and added resistance in regular incident waves of KVLCC2 model

Yavuz Hakan Ozdemir,Baris Barlas 대한조선학회 2017 International Journal of Naval Architecture and Oc Vol.9 No.2

In this study, the numerical investigation of ship motions and added resistance at constant forward velocity of KVLCC2 model is presented. Finite volume CFD code is used to calculate three dimensional, incompressible, unsteady RANS equations. Numerical computations show that reliable numerical results can be obtained in head waves. In the numerical analyses, body attached mesh method is used to simulate the ship motions. Free surface is simulated by using VOF method. The relationship between the turbulence viscosity and the velocities are obtained through the standard k ε turbulence model. The numerical results are examined in terms of ship resistance, ship motions and added resistance. The validation studies are carried out by comparing the present results obtained for the KVLCC2 hull from the literature. It is shown that, ship resistance, pitch and heave motions in regular head waves can be estimated accurately, although, added resistance can be predicted with some error.

COEFFICIENT ESTIMATES FOR CERTAIN SUBCLASS FOR SPIRALLIKE FUNCTIONS DEFINED BY MEANS OF GENERALIZED ATTIYA-SRIVASTAVA OPERATOR

Yavuz, Tugba Korean Mathematical Society 2016 대한수학회논문집 Vol.31 No.4

In this article, we derive a sharp estimates for the Taylor-Maclaurin coefficients of functions in some certain subclasses of spirallike functions which are defined by generalized Srivastava-Attiya operator. Several corollaries and consequences of the main result are also considered.

Effects of Material Properties on Seismic Vulnerability Assessment of Unreinforced Masonry Buildings

Yavuz Yardim,Enea Mustafaraj,Erion Luga 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.5

This study investigates the seismic performance of existing unreinforced masonry buildings considering the effects of different material properties selected from design codes’ assumptions and experimental values. For this purpose, work was conducted to analyze a selection of existing buildings in Albania designed with typical methodologies of the past structural design codes. Experimental investigations were carried out on bricks and mortars extracted from the selected buildings, as well as a series of regular and irregular sized mortar specimens prepared in the laboratory for comparative evaluation purpose. In addition, diagonal compression tests were performed on two full-size (1.2 m × 1.2 m) masonry walls built in the laboratory, which were prepared based on the existing building’s construction method and material properties. Selected typical URM buildings were analyzed with commercial program CDSWin using different masonry mechanical characteristics that were obtained from experimental work in this study. The equivalent frame method (EFM) was used for the modeling of the buildings and pushover analysis was performed to obtain their seismic capacity. To evaluate the seismic response of each case, a comparison was established between the drift ratio and maximum base shear. As a result, using the code assumptions for the mechanical properties of masonry, overly conservative results were obtained. To understand better and clarify how stresses are being distributed in the walls, it is essential to perform experimental investigations to acquire the representative masonry characteristics such that a reliable structure assessment and retrofitting could be implemented.

The Relationship between Presbycusis and Mastoid Pneumatization

Yavuz Selim Pata,Yucel Akbas,Murat Unal,Meltem Nass Duce,Tugana Akbas,Deniz Micozkadioglu 연세대학교의과대학 2004 Yonsei medical journal Vol.45 No.1

Presbycusis is defined as the natural hearing loss accompanying aging, caused by degenerative changes in the inner ear. The etiology of presbycusis is uncertain. However, it would appear that a complex genetic cause is most likely. The determinants of mastoid size continue to be controversial. One of the pneumatization theories is the hereditary theory. In this study, the possible relationship between presbycusis and the extent of mastoid pneumatization was investigated. This study was carried out on 21 patients with presbycusis and 21 normal subjects of similar ages. The pneumatized volume was measured by computerized tomography. The temporal bone was scanned at 2mm thickness intervals. Exposure (kV 130, mA105). The scan plane was parallel to the orbitomeatal line and the CT images covered the entire mastoid region. The average mastoid pneumatization in presbycusis group was 6.08 ±2.52cm3 in the right ear and 6.19±2.93cm3 in the left ear. However, in the control group it was 4.69±3.17cm3 in the right ear (p=0.12) and 5.10±3.49cm3 in the left ear (p=0.28). No significant difference was found between the presbycusis patients and normal subjects in terms of the volume of mastoid pneumatization.

Reconstruction of the Orbit With a Temporalis Muscle Flap After Orbital Exenteration

Yavuz Uya,Tolgar Lütfi Kumral,Güven Yıldırım,Mustafa Kuzdere,Hamdi Arbağ,Chary Jorayev,Mehmet Vefa Kılıç,Said Serdar Gümrükçü 대한이비인후과학회 2015 Clinical and Experimental Otorhinolaryngology Vol.8 No.1

Objectives. This study presents the role of the temporalis muscle flap in primary reconstruction after orbital exenteration. Methods. A retrospective nonrandomized study of orbital exenterations performed between 1990 and 2010 for malignant tumors of the skin, paranasal sinus, and nasal cavity is presented. Results. The study included 13 patients (nine men, four women; age range, 30–82 years) with paranasal sinus, nasal cavity, or skin carcinomas. Primary reconstruction of the cavity was performed in all patients after orbital exenteration. No visible defects in the muscle flap donor site were present. Local recurrences were readily followed up with nasal endoscopy, whereas radiology helped to diagnose intracranial involvement in three patients. Two patients died of systemic metastases and five died for other reasonsConclusion. The temporalis muscle flap is readily used to close the defect after orbital exenteration, and does not prevent the detection of recurrence.

A novel approach for itaconic acid extraction: Mixture of trioctylamine and tridodecylamine in different diluents

Yavuz Selim Asci,Ismail Inci 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.5

Extraction of itaconic acid has been investigated from aqueous solutions by six kind of different solutions of trioctylamine (TOA)–tridodecylamine (TDA) mixtures. Solvents have selected as dimethyl phthalate (DMP), methyl isobutyl ketone (MIBK), 2-octanone, 1-octanol, cyclohexyleacetate (CHA), and 1-decanol. Distribution and equilibrium data for design of separation equipments have been obtained as a result of batch extraction of itaconic acid. It has been calculated that distribution coefficients (D), loading factors (Z), extraction efficiency (E). The maximum removal of itaconic acid has been obtained as 98.39% with DMP and 3.14 mol L-1 initial concentration of TOA–TDA mixture.

Electrodeposition, Characterization and Long Term Stability of NiW and NiWZn Coatings on Copper Substrate in Alkaline Solution

Yavuz Sürme,A. Ali Gürten,Kadriye Kayaklrllmaz 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.4

This paper describes the electrodeposition of Ni, NiW and NiWZn coatings onto copper surfaces from electrolyte solutions containing Na3C6H5O7, Na2WO4, NiSO4 and ZnSO4. The electrocatalytic effects of electrodeposited coatings were investigated for hydrogen evolution reactions in 1 M NaOH solution. Surface characterization studies were carried out by energy dispersive X-ray spectroscopy, scanning electron microscopy,atomic force microscopy and cross-section analysis. The effect of operating conditions on the chemical composition,microstructure and electrocatalytic properties of Ni-W coatings was studied. The Zn ions were used to improve the active surface area and catalytic activity of the electrodeposited surface. The electrocatalytic activity of NiW and NiWZn coated electrodes for the hydrogen evolution reaction in alkaline solution was compared with that of an electrodeposited Ni electrode and copper substrate by using cathodic polarization curves and electrochemical impedance spectroscopy techniques over 96 h of electrolysis. The results proved that the NiWZn coated electrode showed better electrocatalytic activity and durability than bare Cu, Ni and NiW coatings.

Transient response of functionally graded non-uniform cylindrical helical rods

Yavuz C. Cuma,Faruk Firat Calim 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.4

This paper have the objective of investigating forced vibration behaviour of axially functionally graded cylindrical helices with variable cross-section. An algorithm is developed in order to solve corresponding problems. The ordinary differential equations governing the dynamic behaviour of cylindrical helices are determined in Laplace domain by using Timoshenko beam theory. Then transfer matrix method is implemented for the solution, including shear and axial deformation effects. Obtained results are transferred to time domain using Durbin’s modified numerical inverse algorithm for Laplace transform. A benchmark problem has been solved to check the accuracy of developed algorithm then a parametric study is conducted considering the effects of material gradient index ( ), section variation parameter ( ) and number of active turns ( ). Results are compared with solutions attained from ANSYS for verification