Strengthening of reinforced concrete beams using external steel members

Ali Demir,Emre Ercan,Duygu Dönmez Demir 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.27 No.4

The objective of this study is to devise an alternative strengthening method to the ones available in the literature. So, external steel members were used to enhance both flexural and shear capacities of reinforced concrete (RC) beams having insufficient shear capacity. Two types of RC beams, one without stirrups and one with lacking stirrups, were prepared in the study. These beams were strengthened with external steel clamps devised by the authors and with external longitudinal reinforcements. Although the use of clamps alone didn’t have a significant effect on the load carrying capacity of the tested beams, the ductility increased approximately tenfold and the failure behavior changed from brittle to ductile. Although the use of clamps and longitudinal reinforcements together did not significantly increase the ductility of the beams, it approximately doubled their load capacities. The results of the experimental study were compared to the ones obtained from nonlinear finite element analysis (NLFEA) and it was observed that they were compatible. Finally, it can be concluded that the devised method could be applied to structural members as an alternative to methods in application due to lightness, low-cost, easy applicable and reliable.

Influence of deposition conditions on nanostructured InSe thin films

Kübra Çınar Demir,Emre Demir,Seniye Yüksel,Cevdet Coşkun 한국물리학회 2019 Current Applied Physics Vol.19 No.12

In this study, nanostructured indium selenide (InSe) thin films were deposited on Indium tin oxide (ITO)-coated glass substrate using electrochemical deposition (ECD) from aqueous solution containing In(SO4)3.H2O and SeO2. The effects of deposition potential (−0.70 to −1.35 V), time (30-3600 s), temperature (25-80 °C) and pH (2.58 for A samples; 2 for B samples and 1.45 for C samples) on growth of the InSe thin films were examined in terms of their structural, morphological and optical properties. X-ray diffraction (XRD) analysis confirmed that the InSe thin films are in polycrystalline structure. It was found that the values of grain size decreased and the full width half maximum (FWHM) values increased with the increasing deposition potential. According to the absorption measurements, optical properties of the thin films varied with changes in deposition conditions. Based on the atomic force microscopy (AFM) and the scanning electron microscopy (SEM) images, surface morphology of the thin films was influenced by deposition potential and pH of the electrolyte, and nonhomogeneous depositions distributed across the entire surface were observed. In addition, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and fourier transform infrared spectroscopy (FT-IR) analyses were used to further examine crystal quality, vibration, chemical binding conditions, In/Se orientation and structure of the prepared InSe thin films. When Raman results are examined, the B12 sample shows a more intensity and narrow peak at 248 cm−1. XPS measurements sowed that A6 sample exhibited more growth in low potential for a long time and better film stoichiometry compared to the other three samples. Also, FT-IR studies prove the presence of InSe. According to the results, the film did not form at low temperatures and short times. However, the film formation began with the increasing deposition temperature and time at the low potential value of −0.730 V. But, it is clear that a high quality film can be obtained in cathodic potential with −1.3 V and shorter deposition time with 300 s at room temperature respectively. Overall results showed that the high quality thin films can be obtained by the ECD technique. However, deposition conditions must be sensitively adjusted to control morphology of the electrodeposited nanoparticles.

Effect of model calibration on seismic behaviour of a historical mosque

Ali Demir,Halil Nohutcu,Emre Ercan,Emin Hokelekli,Gokhan Altintas 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.60 No.5

The objective of the study is to investigate the effects of model calibration on seismic behaviour of a historical mosque which is one of the most significant Ottomon structures. Seismic analyses of calibrated and noncalibrated numeric models were carried out by using acceleration records of Kocaeli earthquake in 1999. In numerical analysis, existing crack zones on real structure was investigated in detail. As a result of analyses, maximum stresses and displacements of calibrated and noncalibrated numerical models were compared each other. Consequently, seismic behaviour and damage state of historical masonry Hafsa Sultan mosque was determined as more realistic in the event of a severe earthquake.

Reformulation of Multi uid Plasma Equations in Terms of Spacetime Algebra

S¨uleyman Demir,Murat Tanisli,Neslihan Sahin,Mustafa Emre Kansu 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.5

Using the exact isomorphism between multi uid plasma theory and classical electromagnetism, we apply the theorems and techniques of spacetime algebra to the multi uid equations of a plasma in order to present a new formulation in a compact and elegant way. A set of Maxwell equations for a plasma is combined into a single equation similar to their counterparts in electromagnetism, linear gravitation and uid mechanics. The presented formulation also proposes a useful method for the generalization of the plasma wave equation.

A new risk scoring system for early prediction of surgical need in patients with adhesive small bowel obstruction: a single-center retrospective clinical study

Evren Besler,Emre Teke,Do?ukan Akku?,Mahmut Hudai Demir,Sebahat Aksaray,Sibel Aydın Aksu,Meryem Gunay Gurleyik 대한외과학회 2023 Annals of Surgical Treatment and Research(ASRT) Vol.105 No.3

Recent developments in cancer therapy and diagnosis

Atlihan-Gundogdu Evren,Ilem-Ozdemir Derya,Ekinci Meliha,Ozgenc Emre,Demir Emine Selin,Sánchez-Dengra Bárbara,González-Alvárez Isabel 한국약제학회 2020 Journal of Pharmaceutical Investigation Vol.50 No.4

Background The cancer is serious health problem and leading cause of death in the world. Area covered There have intensively studied for diagnosis and therapy of this disease and these studies provided important insights into their mechanism of action and therapeutic/diagnostic effects. The accurence rates of cancer has dramatic increase, particularly in the developed countries. Although there are many different strategies about diagnosis and treatment for cancer, more effective new approaches are needed. Expert opinion In this review, we summarize recent developments on cancer diagnosis, radiopharmaceuticals in cancer diagnosis, nanoparticulate systems in cancer diagnosis, T cells in cancer diagnosis, cancer therapy and pharmacokinetic of anticancer drugs. We thought that while there are some current limitations such as clinical studies, ranging from diagnosis to theraphy, future improvements in cancer diagnosis and treatment will meet the most relevant issues required for the eventual approval of nano-drugs, radiopharmaceuticals, T cells in clinical practice.

The effect of atropine in preventing catheter-related pain and discomfort in patients undergoing transurethral resection due to bladder tumor; prospective randomized, controlled study

Yeliz Şahiner,Özgür Yağan,Arzu Akdağlı Ekici,Musa Ekici,Emre Demir 대한통증학회 2020 The Korean Journal of Pain Vol.33 No.2

Background: Catheter-related bladder discomfort (CRBD) has been observed in many patients undergoing a urethral catheterization. CRBD may be so severe that the patients require additional analgesics. Muscarinic receptors are involved in the mechanism of CRBD. The aim of this study is to determine the effects of the anti-muscarinic properties of atropine, which is frequently used in current practice on CRBD, by comparing it with sugammadex which has no antimuscarinic effects.Methods: Sixty patients selected for transurethral resection due to bladder tumors were randomized into 2 groups: an atropine group and a sugammadex group, with no antimuscarinic effect. The patients were given rocuronium (0.6 mg/kg) as a neu-romuscular-blocker. In addition to the frequency and severity of CRBD postopera-tively at 0, 1, 6, 12, and 24 hours, postoperative numeric rating scale (NRS) scores, and postoperative nausea and vomiting were examined.Results: The incidence of CRBD was significantly lower in the atropine group in all postoperative measurements. The score was found to be significantly lower in the atropine group when NRS measurements were performed at all time periods (P < 0.01). There was no difference between the groups in terms of nausea and vomiting (P > 0.05).Conclusions: Atropine is a cheap, easy-to-access, safe-to-use drug for reducing CRBD symptoms, without any observed adverse effects. Since it not only reduces CRBD symptoms but also has a positive effect on postoperative pain, it can be used safely to increase patient comfort in patients receiving general anesthesia and a urinary catheter.