Experimental study on standard and innovative bolted end-plate beam-to-beam joints under bending

Levente Katula,László Dunai 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.6

The paper presents the details and results of an experimental study on bolted end-plate joints of industrial type steel building frames. The investigated joints are commonly used in Lindab-Astron industrial buildings and are optimized for manufacturing, erection and durability. The aim of the research was to provide an experimental background for the design model development by studying load-bearing capacity of joints, bolt force distribution, and end-plate deformations. Because of the special joint details, (i.e., joints with four bolts in one bolt-row and HammerHead arrangements), the Eurocode 3 standardized component model had to be improved and extended. The experimental programme included six different end-plate and bolt arrangements and covered sixteen specimens. The steel grade of test specimens was S355, the bolt diameter M20, whereas the bolt grade was 8.8 and 10.9 for the two series. The end-plate thickness varied between 12 mm and 24 mm. The specimens were investigated under pure bending conditions using a four-point-bending test arrangement. In all tests the typical displacements and the bolt force distribution were measured. The end-plate plastic deformations were measured after the tests by an automatic measuring device. The measured data were presented and evaluated by the moment-bolt-row force and momentdistance from centre of compression diagrams and by the deformed end-plate surfaces. From the results the typical failure modes and the joint behaviour were specified and presented. Furthermore the influence of the end-plate thickness and the pretension of the bolts on the behaviour of bolted joints were analysed.

Hard rock and soft ground tunnel boring technology

Levent Ozdemir 한국암반공학회 2003 한국암반공학회 학술대회 및 세미나 자료집 Vol.- No.-

Re: Histologic Evidence of New Collagen Formulation Using Platelet Rich Plasma in Skin Rejuvenation: A Prospective Controlled Clinical Study

( Levent Tekin ) 대한피부과학회 2018 Annals of Dermatology Vol.30 No.1

Efficiency of MVP ECG Risk Score for Prediction of Long-Term Atrial Fibrillation in Patients With ICD for Heart Failure With Reduced Ejection Fraction

Levent Pay,Ahmet Çağdaş Yumurtaş,Ozan Tezen,Tuğba Çetin,Semih Eren,Göksel Çinier,Mert İlker Hayıroğlu,Ahmet İlker Tekkeşin 대한심장학회 2023 Korean Circulation Journal Vol.53 No.9

Background and Objectives: The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up. Methods: The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups. Results: The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group. Conclusions: The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

Split quaternions and rotations in semi Euclidean space $\mathbb{E}_{2}^{4}$

Levent Kula,Yusuf Yayli 대한수학회 2007 대한수학회지 Vol.44 No.6

Estimation of the Compressive Strength of Concrete under Point Load and its Approach to Strength Criterions

Levent Selçuk,H. Süleyman Gökçe 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.6

The point load strength (Is(50)) is an alternative mechanical parameter to predict the compressive strength of concrete. The scope of this investigation is to develop an empirical equation relating the point load strength and compressive strength of concrete. In this context, crushed limestone aggregates at two different strength levels were used in concrete mixture. Point load strength and compressive strength tests on concrete specimens which had 6 different compressive strengths were performed for each limestone aggregate. A series of regression analyses was applied using any general statistical package to evaluate the ratio of point load strength test to cube compressive strength of concrete, (Is(50)/fcu). The accuracy and reliability of the equation in this investigation was assessed by means of the Mean Absolute Percent Error (MAPE). The relative error can be considered reasonably well for the empirical relationship. The ratio of Is(50)/fcu was also verified by a large database collected from previous studies. The proposed equation is quite compatible with the database. Furthermore, the ratio of Is(50)/fcu indicates significant material property of concrete and defines the material constant in strength criterions. It can be used to estimate the axial compressive strength of concrete under confining stress without performing triaxial tests, considered Hoek-Brown and Johnson empirical failure criterions.

Is SYNTAX Score Predictive of Atrial Fibrillation after On-Pump Coronary Artery Bypass Graft Surgery?

Levent Cerit,Hamza Duygu,Kamil Gulsen,Hatice S Kemal,Barcın Ozcem,Ozlem Balcioglu,Aziz Gunsel,Ozgur Tosun,Volkan Emren 대한심장학회 2016 Korean Circulation Journal Vol.46 No.6

Background and Objectives: The relationship of synergy between percutaneous coronary intervention with taxus and cardiac surgery (SYNTAX) score and development of atrial fibrillation (AF) after coronary artery bypass surgery (CABG) has not been studied. Therefore, we assessed the relationship between the SYNTAX score and development of AF after CABG (POAF). Subjects and Methods: The medical records of consecutive patients, who underwent CABG surgery from January 2013 to September 2015, were retrospectively reviewed for the development of AF in the postoperative period. SYNTAX score, clinical and echocardiographic parameters were evaluated. The independent variables for the development of POAF were defined and their predictive values were measured. Results: The study group consisted of 106 patients, of which 36 (34%) developed POAF. Age, hypertension, stroke, chronic obstructive pulmonary disease (COPD), heart failure (HF), diabetes mellitus (DM), left atrial diameter, neutrophil/lymphocyte ratio, platelet large cell ratio, creatinine, blood urea nitrogen and SYNTAX score were identified as important variables for the development of POAF. However, in logistic regression analysis COPD (OR=19.313, 95% CI=2.416-154.407, p=0.005), HF (OR=28.362, 95% CI=2.034-395.515, p=0.013), SYNTAX score (OR=0.863, 95% CI=0.757-0.983, p=0.026), and DM (OR=20.770, 95% CI=3.791-113.799, p<0.001) appeared as independent variables predicting the development of POAF. In receiver operation characteristic analysis, SYNTAX score (≥22.25) (AUC=0.777, 95% CI=0.676-0.877, p<0.001) was one of the strongest predictors for the development of POAF. Conclusion: The SYNTAX score level was independently associated with the development of AF after CABG.

Mytilus Galloprovincialis and Metal Contaminants: Health Risk Assessment from Sinop Coasts

Levent BAT,Ayş,ah Ö,ZTEKIN,Elif ARICI,Fatih Ş,AHIN 한국식품보건융합학회 2021 식품보건융합연구 (KJFHC) Vol.7 No.4

The goal of this study was to quantify the content of heavy metals (Zn, Cu, Cd, Pb, Hg) in the bivalve Mytilus galloprovincialis, which was obtained from the Black Sea s Sinop peninsula, as well as estimate the health risks. Concentrations of heavy metals in mussels’ soft tissues ranged between 16.4-21.8, 0.52-0.93, 0.13-0.45; 0.015-0.019 and 0.006-0.011mg kg-1 wet weight for Zn, Cu, Pb, Hg and Cd, respectively. In general, metal concentrations in mussels were quite low. In mussels, Zn was the most prevalent element, followed by Cu. Regarding the monthly variation, although relatively higher tissue metal concentrations were observed in August compared to July, no statistical difference was found. The estimated daily intakes did not exceed the tolerable intakes. There was no health risk since the total hazard index was far below critical value 1. This demonstrates that eating mussels from the Sinop coasts in 2019 does not cause any health risks in infants, children, or adult. Mussels have a risk index of less than 10-6, which is considered insignificant. In conclusion, the results of this study show that there is no heavy metal pollution in the mussels collected from Sinop coasts.

Epistemology of Muslims in Pre-Meiji Japan

LEVENT. Sinan 한국중동학회 2012 한국중동학회 학술대회 자료집 Vol.2012 No.-

CoNeT Mobile Laboratory for Ethernet Based I/O Systems in Industrial Applications

Levent Ucun,Onur Akbatı,Galip Cansever 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

This paper studies Ethernet based I/O systems in industrial applications. This study is involved in CoNeT, the European Union funded project, which stands for Cooperative Network Training. The project aims at training of automation engineers, maintenance engineers, process workers and students both graduate and undergraduate in modern wired and wireless industrial network technology applied to control operations and automated solutions. Seven modules dealing with different subjects about industrial automation have been designed in the concept of the project. This study has been carried out to design the first module which is about training in Ethernet based I/O systems. Mobile laboratory involving different industrial communication devices from different automation manufacturers has been founded and industrial application-oriented experiments have been designed to be carried out in the mobile laboratory.