Hygrothermal stress analysis of laminated composite porous plates

Y.Z. Yüksel,Ş.D. Akbaş 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.80 No.1

This paper presents the stress analysis of a composite laminated simply supported plate with porosity under hygrothermal rising. In the displacement-strain relation of the plate structure, the first shear plate deformation theory is used. Material properties of laminas are considered as orthotropic. Three different porosity distributions are used. In the solution process, the Navier method is implemented for simply supported laminated composite plate. Non-uniform temperature and moisture rising are considered for laminated plate with three laminas. In the numerical results, the stress distributions of the laminated plate are presented and discussed for different values of moisture, temperature, stacking sequence of laminas and orientation angle of layers. The numerical results show that the hygrothermal condition is very effective in the stress behavior of laminated plates.

Some Characteristics and Isolation of Novel Thermostable β-Galactosidase from Thermus oshimai DSM 12092

Yüksel Gezgin,Bahattin Tanyolac,Rengin Eltem 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.1

The β-galactosidases belong to the class of hydrolytic enzymes and have been used as lactose hyrolysis. The enzyme is used in reducing lactose milk production, an outstanding industrial product used by a large lactoseintolerant population. This is the first detailed report of some characteristics of β-galactosidase and the gene encoding β-galactosidase in Thermus oshimai DSM 12092. The growth rate (μ, 1/h), and the doubling time (tD, h) for T. oshimai grown both in shaking flasks and in a bioreactor were determined. The optimal temperature and pH for β-galactosidase were determined as 75oC and 7.4, respectively. This enzyme was thermostable and was retained by more than 70% at 90oC for 3 h. The β-galactosidase from T. oshimai DSM 12092 was more stable in basic pH and Zn2+was the most effective divalent cation. Also, 2 steps of purification consisting of ammonium sulfate precipitation and gel filtration were employed and purified 32-fold.

Can tumor recurrence be reduced with plasma-kinetic vaporization of the area around the tumor in nonmuscle invasive bladder cancer?

Yüksel Yılmaz,Mehmet Cemal Kahya,Fatma Hüsniye Dilek,Osman Köse,Serkan Özcan,Ertan Can,Yiğit Akın,Batuhan Ergani,Ahmet Selçuk Dindar 대한비뇨의학회 2018 Investigative and Clinical Urology Vol.59 No.4

Purpose: To investigate the effect on recurrence of vaporization of the tumor surroundings and suspicious areas with a plasma-kinetic (PK) system after transurethral resection (TUR) of nonmuscle invasive bladder cancer. Materials and Methods: The study included 121 patients with a primary superficial bladder tumor who were randomized as those who underwent TUR with the PK system (Group 1, n=62) and those who underwent TUR with the monopolar system (Group 2, n=59). The vaporization procedure was performed by suppressing the cutting option of the PK system for a period, which would accumulate energy sufficient to make swelling-waves on the mucosa very close to the area of the loop to be vaporized. Results: A total of 121 patients who met the study criteria were included for evaluation. Recurrence was determined in 21 patients in Group 1 (33.87%) and in 29 patients in Group 2 (49.15%) (p=0.088). Recurrence was close to the old resection site in 6 of 21 patients in Group 1, and in 13 patients in Group 2 (p=0.028); the difference was statistically significant. No statistically significant difference was determined between the two groups with respect to age, gender, number of tumor foci, rate or range of additional treatments applied, cigarette smoking rate, repeat TUR rate and rate of tumor en- countered in repeat TUR, T-stage, and tumor grade. Conclusions: The effect of vaporization on recurrence by the PK system may seem similar to the effect of standard TUR, the recurrence- lowering effect surrounding nonmuscle invasive bladder cancers is better.

The tension in Turkish teacher education: Conflict and controversy during the transformation from an academic approach to a professional approach

Sedat Yüksel 서울대학교 교육연구소 2008 Asia Pacific Education Review Vol.9 No.3

Most of the reforms, which have been undertaken in the last 30 years in the Turkish educational system, are about teacher education, When we examine the teacher education curriculum from the perspective of these reforms, it has been observed that there is a controversy between the academic and professional approaches used in these curricula. While the reforms undertaken in 1982 and 1997 were in favor of the academic approach, the latest reform undertaken in 2006 was made to strengthen the professional aspects of teacher education curriculum. In this paper, Turkish teacher education reforms are introduced in the light of the professional and the academic approaches, which have always been the topic of discussions about teacher education.

Publication Trends in the Pelvic Parameter Related Literature between 1992 and 2022 : A Bibliometric Review

Serdar Yüksel,Emre Özmen,Alican Barış,Esra Circi,Ozan Beytemür 대한신경외과학회 2024 Journal of Korean neurosurgical society Vol.67 No.1

Objective : This study aimed to conduct a bibliometric analysis on pelvic parameter related research over the last 30 years, analyzing trends, hotspots, and influential works within this field. Methods : A comprehensive Web of Science database search was performed. The search yielded 3249 results, focusing on articles and reviews published from 1992 to 2022 in English. Data was analyzed using CiteSpace and VOSviewer for keyword, authorship, and citation burst analysis, co-citation analysis, and clustering. Results : The number of publications and citations related to pelvic parameters has increased exponentially over the last 30 years. The USA leads in publication count with 1003 articles. Top publishing journals include the European Spine Journal, Spine, and Journal of Neurosurgery: Spine, with significant contributions by Schwab, Lafage V, and Protoptaltis. The most influential articles were identified using centrality and sigma values, indicating their role as key articles within the field. Research hotspots included spinal deformity, total hip arthroplasty, and sagittal alignment. Conclusion : Interest in pelvic parameter related research has grown significantly over the last three decades, indicating its relevance in modern orthopedics. The most influential works within this field have contributed to our understanding of spinal deformity, pelvic incidence, and their relation to total hip arthroplasty. This study provides a comprehensive overview of the trends and influential research in the field of pelvic parameters.

Quasi-static cyclic displacement pattern for seismic evaluation of reinforced concrete columns

E. Yüksel,M. Sürmeli 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.37 No.3

Although earthquakes generate random cyclic lateral loading on structures, a quasi-static cyclic loading pattern with gradually increasing amplitude has been commonly used in the laboratory tests because of its relatively low cost and simplicity compared with pseudo-dynamic and shake table tests. The number, amplitudes and sequence of cycles must be chosen appropriately as important parameters of a quasi-static cyclic loading pattern in order to account for cumulative damage matter. This paper aims to reach a new cyclic displacement pattern to be used in quasi-static tests of well-confined, flexure-dominated reinforced concrete (RC) columns. The main parameters of the study are sectional dimensions, percentage of longitudinal reinforcement, axial force intensity and earthquake types, namely, far-fault and near-fault.

Rebar corrosion effects on structural behavior of buildings

İsa Yüksel 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.6

Rebar corrosion in concrete is one of the main causes of reduction of service life of reinforced concrete buildings. This paper presents the influence of rebar corrosion on the structural behavior of reinforced concrete (RC) buildings subjected to strong earthquake ground motion. Different levels of rebar corrosion scenarios were applied on a typical four story RC frame. The deteriorated conditions as a result of these scenarios include loss in cross-sectional area and loss of mechanical properties of the reinforcement bars, loss in bond strength, and loss in concrete strength and its modulus of elasticity. Dynamic analyses of the frame with different corrosion scenarios are performed with selected strong earthquake ground motion records. The influences of degradation in both concrete and reinforcement on structural behavior are investigated by comparing the various parameters of the frame under different corrosion scenarios with respect to each other. The results show that the progressive deterioration of the frame due to rebar corrosion causes serious structural behavior changes such as change in failure mode. The intensity, propagation time, and extensity of rebar corrosion have very important effects on the level of degradation of steel and concrete, as well as on the earthquake behavior of the structure.

An Investigation of the Volatile Compound Profiles of Probiotic Yogurts Produced Using Different Inulin and Demineralised Whey Powder Combinations

Arzu Kavaz Yüksel,İhsan Bakırcı 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.3

Volatile compound profiles of probiotic yogurt samples prepared using 8 different prebiotic combinations were analyzed using gas chromatography/mass spectrometry (GC-MS) with solid phase micro extraction during 28 days of storage. A total of 40 volatile compounds were identified in yogurt samples during storage consisting of 2 aldehydes, 6 ketones, 4 alcohols, 6 acids, 5 esters, 3 terpenes, 3 aromatic hydrocarbons, and 12 aliphatic hydro-carbons. Acetaldehyde, diacetyl, acetoin, 2-heptanone, ethanol, isoamyl alcohol, acetic acid, caproic acid, caprilic acid, and capric acid were the major volatile compounds in all probiotic yogurt samples.

Neuro-fuzzy and artificial neural networks modeling of uniform temperature effects of symmetric parabolic haunched beams

S. Bahadır Yüksel,Alpaslan Yarar 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.56 No.5

When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. The computation of design forces for the non-prismatic beams having symmetrical parabolic haunches (NBSPH) is fairly difficult because of the parabolic change of the cross section. Due to their non-prismatic geometrical configuration, their assessment, particularly the computation of fixed-end horizontal forces and fixed-end moments becomes a complex problem. In this study, the efficiency of the Artificial Neural Networks (ANN) and Adaptive Neuro Fuzzy Inference Systems (ANFIS) in predicting the design forces and the design moments of the NBSPH due to temperature changes was investigated. Previously obtained finite element analyses results in the literature were used to train and test the ANN and ANFIS models. The performances of the different models were evaluated by comparing the corresponding values of mean squared errors (MSE) and decisive coefficients (R2). In addition to this, the comparison of ANN and ANFIS with traditional methods was made by setting up Linear-regression (LR) model.

Association of Neutrophil/Lymphocyte Ratio with Plaque Morphology in Patients with Asymptomatic Intermediate Carotid Artery Stenosis

İsa Öner Yüksel,Erkan Köklü,,Şakir Arslan,Göksel Çağırcı,Eylem Özaydın Göksu,Pınar Koç,Serkan Çay,Filiz Kızılırmak 대한심장학회 2016 Korean Circulation Journal Vol.46 No.5

Background and Objectives: Non-calcified carotid plaques are more unstable than calcified plaques, and they are associated with a higher risk of rupture, thromboembolism, and consequently, stroke. The purpose of the present study is to compare calcified and non-calcified plaques that cause intermediate carotid artery stenosis with respect to neutrophil/lymphocyte ratio (NLR). Subjects and Methods: A total number of 139 asymptomatic patients with 50-70% stenosis of the carotid artery were included in this study. Carotid Doppler ultrasound imaging and computed tomography angiography were performed to divide the carotid artery plaques into two groups as calcified and non-calcified. Patients included in the calcified (n=73) and non-calcified (n=66) plaque groups were compared with respect to total neutrophil count, lymphocyte count and NLR. Results: Total lymphocyte count was statistically significantly lower in the non-calcified plaque group compared to the calcified plaque group (total lymphocyte count in non-calcified/calcified plaque groups [103/mm3]: 2.1/2.3, respectively) (p=0.002). NLR was statistically significantly higher in the non-calcified plaque group compared to the calcified plaque group (NLR in non-calcified/calcified plaque groups: 2.6/2.1, respectively) (p<0.001). The cut-off value for NLR was found to be >2.54. Multivariate regression analysis showed that NLR was independently associated with non-calcified carotid artery plaques (odds ratio 5.686, 95% CI 2.498-12.944, p<0.001). Conclusions: NLR is increased in the presence of non-calcified carotid artery plaques that cause asymptomatic intermediate stenosis. Increased NLR can be used as a marker to assess the risk of rupture of non-calcified carotid artery plaques.