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.

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.

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.

Effect of Probiotics on the Treatment of Children with Atopic Dermatitis

( Yavuz Yesilova ),( Omer Calka ),( Necmettin Akdeniz ),( Mustafa Berktas ) 대한피부과학회 2012 Annals of Dermatology Vol.24 No.2

Background: Atopic dermatitis, a chronic recurrent disease, is frequently encountered in clinical practice. In the last 30 years, the prevalence of atopic dermatitis has rapidly increased due to industrialization. Therefore, there have been attempts in recent years to find new ways of treating and preventing atopic dermatitis. Objective: In this double-blind, randomized, placebo-controlled study, a combination of Bifidobacterium bifidum, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus salivarius strains were evaluated in the treatment of atopic dermatitis in pediatric patients. Methods: Forty pediatric patients (23 males and 17 females) aged 1∼13 years were enrolled. One eligible individual who was approached declined to participate. The probiotic group was administered a probiotic complex containing B. bifidum, L. acidophilus, L. casei, and L. salivarius for 8 weeks. The placebo group, on the other hand, was administered skim milk powder and dextrose. All of the parameters including serum cytokines, eosinophil cationic protein), SCORing Atopic Dermatitis (SCORAD) index, and total serum immunoglobulin E (IgE) were measured in both the probiotic group and the placebo group at the end of 8 weeks. Results: Probiotic intervention in pediatric atopic dermatitis patients effectively reduced the SCORAD index and serum cytokines interleukin (IL)-5, IL-6, interferon (IFN)-γ, and total serum IgE levels, but did not reduce levels of serum cytokines IL-2, IL-4, IL-10, ECP, or tumor necrosis factor-α (TNF-α) compared to the placebo group. Conclusion: Our study found probiotics to be effective in reducing atopic dermatitis patients` SCORAD index, serum IL-5, IL-6, IFN-γ, and total serum IgE levels but not effective in reducing serum IL-2, IL-4, IL-10, ECP, or TNF-α levels. (Ann Dermatol 24(2) 189∼193, 2012)

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.

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.

Role of Reinforcement Materials on Mechanical and Tribological Properties of PTFE Composites

Yavuz Kaplan 한국고분자학회 2020 폴리머 Vol.44 No.4

The use of polytetrafluoroethylene (PTFE) in various industrial applications under extreme operating conditions makes it very important to determine the behavior of this material. The mechanical and wear properties of PTFE can be enhanced by adding filler materials. This study focused on both the mechanical and tribological properties of PTFE and its composites with a 25 wt% addition of carbon and glass fiber (GF). Glass transition temperature (Tg), hardness, tensile, and impact tests were carried out to determine the mechanical and physical properties of PTFE. In addition, abrasive wear tests were applied to obtain wear behavior. The tensile strength values of the pure and C/GF-filled PTFE were found as 28, 16.7, and 18.6MPa, respectively. Tensile tests clearly showed that the filler materials led to a reduction of the tensile strength and elongation at break of the PTFE. Impact energy values were similarly decreased by the addition of filler materials. However, the carbon and GF additions significantly increased the abrasive wear resistance and Tg of the PTFE. Consequently, carbon and GF-filled PTFE would be a suitable candidate for use in tribological applications.

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

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.

NEW CHARACTERIZATION OF THE CLASS OF STARLIKE FUNCTIONS

Yavuz, Emel,Polatoglu, Yasar,Owa, Shigeyoshi Korean Mathematical Society 2008 대한수학회보 Vol.45 No.4

For analytic functions f(z) in the open unit disc $\mathbb{D}$, an operator $N_{\alpha}(f(z))$ relating with starlike functions is introduced. The object of the present paper is to discuss some properties of the operator $N_{\alpha}(f(z))$.