Investigation of Tie Bars Axial Force Demands in Composite Plate Shear Walls—Concrete Filled

Erkan Polat,Hadi Kenarangi,Michel Bruneau 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.3

Tie bars axial force demands due to concrete dilation and prying action were investigated through numerical studies. In the fi rst part of this study, the Karagozian and Case Concrete model, which proved to provide reasonable in-plane fl exural cyclic inelastic wall response while accounting for concrete dilation eff ect, was used to investigate the variation of confi nement inside the infi ll concrete, the distribution of passive confi ning pressures at the steel–concrete interface, and the resulting tie bar axial force demands. Finite element analyses involving C-PSW/CF having diff erent tie spacings, wall depths, and wall thicknesses were performed. In the second part of this study, the infl uence of plate local buckling on tie bar axial force demand was investigated and explained by prying action. A separate fi nite element study was performed to investigate the signifi cance of prying action and equations were developed from free-body diagrams. The results showed the signifi cance of the passive confi ning pressures due to concrete dilation, and prying action due to local plate buckling, on imparting axial forces in tie bars. Neither of these behavior are currently considered as design parameters for tie bars. The numerical analyses and results presented here are intended to provide useful insights and direction for the design and instrumentation of future C-PSW/CF experiments by the broader research community.

Theoretical Models for Tie Bar Maximum Axial Force Demand in Composite Plate Shear Walls–Concrete Filled

Erkan Polat 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.4

This paper presents theoretical models developed for the prediction of the maximum axial force demands of tie bars of planar composite plate shear walls–concrete fi lled (C-PSW/CF). In the development of the theory, a previously benchmarked fi nite element (FE) wall model was used with some modifi cations. The results from the FE models were used to demonstrate the formation of the tie bar axial force demands, passive lateral confi ning pressure, concrete confi nement, eff ectively confi ned concrete core and to develop theoretical models for the prediction of tie bar maximum force demands. The proposed method accounts for various aspects of wall geometry such as horizontal and vertical tie bar spacings, steel plate thickness, and wall thickness. The predictions of the proposed theoretical models were compared with the predictions of FE analyses by performing a parametric study involving C-PSW/CF having diff erent tie bar spacings, plate thickness, wall thickness, and wall depths. Past experimental research available in the literature were used to evaluate the signifi cance of the theoretical model in predicting tie bar maximum axial force demands. Tie bar axial force demand due to the confi nement eff ect is not currently considered in the design of tie bars and there is no theoretical approach in the literature that considers the eff ect of confi nement on the tie bar axial force demand. The theoretical models presented in this study allow the determination of the maximum axial force demands due to the confi nement eff ect on planar C-PSW/CF tie bars without the need for complex and costly numerical analysis.

Internalized Stigma in Pediatric Psoriasis: A Comparative Multicenter Study

( Erkan Alpsoy Mualla Polat ),( Ibrahim Halil Yavuz ),( Pelin Kartal ),( Didem Didar Balci ),( Ayse Serap Karadag ),( Asli Bilgic Ercan Arca ),( Bilge Fettahlioglu Karaman ),( Selma Emre ),( Esra Adis 대한피부과학회 2020 Annals of Dermatology Vol.32 No.3

Background: Internalized stigma, adoption of negative attitudes and stereotypes of the society regarding persons’ illness, has not been studied previously in pediatric psoriasis patients. Objective: We aimed to investigate the internalized stigma in pediatric psoriasis patients and to determine differences according to factors affecting internalized stigma compared to adult psoriasis patients. Methods: This multicenter, cross-sectional, comparative study included 125 pediatric (55 female, 70 male; mean age±standard deviation [SD], 14.59±2.87 years) and 1,235 adult psoriasis patients (577 female, 658 male; mean age±SD, 43.3±13.7 years). Psoriasis Internalized Stigma Scale (PISS), Dermatology Life Quality Index (DLQI), Perceived Health Status (PHS), and the General Health Questionnaire (GHQ)-12 were the scales used in the study. Results: The mean PISS was 58.48±14.9 in pediatric group. When PISS subscales of groups were compared, the pediatric group had significantly higher stigma resistance (p=0.01) whereas adult group had higher scores of alienation (p=0.01) and stereotype endorsement (p=0.04). There was a strong correlation between mean values of PISS and DLQI (r=0.423, p=0.001). High internalized stigma scores had no relation to either the severity or localization of disease in pediatric group. However, poor PHS (p=0.007) and low-income levels (p=0.03) in both groups, and body mass index (r=0.181, p=0.04) in the pediatric group were related to high PISS scores. Conclusion: Internalized stigma in pediatric patients is as high as adults and is related to poor quality of life, general health, and psychological illnesses. Unlike adults, internalized stigma was mainly determined by psoriasis per se, rather than disease severity or involvement of visible body parts, genitalia or folds. (Ann Dermatol 32(3) 181∼188, 2020)

Effects of Hot Water Dip and Modified Atmosphere on the Storage of Capia Type Peppers

Ersin Polat,Mustafa Erkan,Isilay Karasahin 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

An improved particle swarm optimizer for steel grillage systems

Ferhat Erdal,Erkan Doğan,Mehmet Polat Saka 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.4

In this paper, an improved version of particle swarm optimization based optimum design algorithm (IPSO) is presented for the steel grillage systems. The optimum design problem is formulated considering the provisions of American Institute of Steel Construction concerning Load and Resistance Factor Design. The optimum design algorithm selects the appropriate W-sections for the beams of the grillage system such that the design constraints are satisfied and the grillage weight is the minimum. When an improved version of the technique is extended to be implemented, the related results and convergence performance prove to be better than the simple particle swarm optimization algorithm and some other metaheuristic optimization techniques. The efficiency of different inertia weight parameters of the proposed algorithm is also numerically investigated considering a number of numerical grillage system examples.

The importance of periprostatic fat tissue thickness measured by preoperative multiparametric magnetic resonance imaging in upstage prediction after robot-assisted radical prostatectomy

Emre Uzun,Muhammed Emin Polat,Kazim Ceviz,Erkan Olcucuoglu,Sedat Tastemur,Yusuf Kasap,Samet Senel,Ozkan Ozdemir 대한비뇨의학회 2024 Investigative and Clinical Urology Vol.65 No.1

Purpose: We analyzed the surgical results of patients who were treated and followed up for prostate cancer in our clinic to predict the relationship between periprostatic adipose tissue and patients with and without pathologically upstaged disease. Materials and Methods: The study included patients who had undergone robot-assisted radical prostatectomy and preoperative multiparametric prostate magnetic resonance imaging between 18 February 2019 and 1 April 2022. The patients were divided into two groups, and the surgical and transrectal ultrasound-guided biopsy pathology results were compared according to tumor grade and distribution in 124 patients who met the selection criteria. We analyzed the relationships between upgrading/upstaging and periprostatic adipose tissue thickness (PPATT) and subcutaneous adipose tissue thickness (SATT) as measured in magnetic resonance imaging. Results: The median PPATT was 4.03 mm, whereas the median SATT was 36.4 mm. Upgrading was detected in 45 patients (36.3%), and upstaging was detected in 42 patients (33.9%). A receiver operating characteristic regression analysis revealed that a PPATT >3 mm was a predictive factor for upstaging after radical prostatectomy (area under curve=0.623, 95% confidence interval [CI] 0.519–0.727, p=0.025). Multivariate logistic regression analyses revealed that prostate specific antigen density ≥0.15 ng/mL/cm3 (odds ratio [OR] 5.054, 95% CI 2.008–12.724, p=0.001), International Society of Urological Pathology grade ≥4 (OR 9.369, 95% CI 2.109–21.626, p=0.003) and higher PPATT (OR 1.358, 95% CI 1.081–1.707, p=0.009) were independent risk factors for upstaging after radical prostatectomy. Conclusions: We believe that the PPATT may be a predictive indicator for upstaging after robot-assisted laparoscopic radical prostatectomy.

An improved particle swarm optimizer for steel grillage systems

Erdal, Ferhat,Dogan, Erkan,Saka, Mehmet Polat Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.4

In this paper, an improved version of particle swarm optimization based optimum design algorithm (IPSO) is presented for the steel grillage systems. The optimum design problem is formulated considering the provisions of American Institute of Steel Construction concerning Load and Resistance Factor Design. The optimum design algorithm selects the appropriate W-sections for the beams of the grillage system such that the design constraints are satisfied and the grillage weight is the minimum. When an improved version of the technique is extended to be implemented, the related results and convergence performance prove to be better than the simple particle swarm optimization algorithm and some other metaheuristic optimization techniques. The efficiency of different inertia weight parameters of the proposed algorithm is also numerically investigated considering a number of numerical grillage system examples.

Comparison of three different risk-stratification models for predicting lymph node involvement in endometrioid endometrial cancer clinically confined to the uterus

Vakkas Korkmaz,Mehmet Mutlu Meydanli,Ibrahim Yalçın,Mustafa Erkan Sarı,Hanifi Sahin,Eda Kocaman,Ali Haberal,Polat Dursun,Tayfun Güngör,Ali Ayhan 대한부인종양학회 2017 Journal of Gynecologic Oncology Vol.28 No.6

Objective: To compare the clinical validity of the Gynecologic Oncology Group-99 (GOG-99), the Mayo-modified and the European Society for Medical Oncology (ESMO)-modified criteria for predicting lymph node (LN) involvement in women with endometrioid endometrial cancer (EC) clinically confined to the uterus. Methods: A total of 625 consecutive women who underwent comprehensive surgical staging for endometrioid EC clinically confined to the uterus were divided into low- and high-risk groups according to the GOG-99, the Mayo-modified, and the ESMO-modified criteria. Lymphovascular space invasion is the cornerstone of risk stratification according to the ESMO-modified criteria. These 3 risk stratification models were compared in terms of predicting LN positivity. Results: Systematic LN dissection was achieved in all patients included in the study. LN involvement was detected in 70 (11.2%) patients. LN involvement was correctly estimated in 51 of 70 LN-positive patients according to the GOG-99 criteria (positive likelihood ratio [LR+], 3.3; negative likelihood ratio [LR−], 0.4), 64 of 70 LN-positive patients according to the ESMO-modified criteria (LR+, 2.5; LR−, 0.13) and 69 of the 70 LN-positive patients according to the Mayo-modified criteria (LR+, 2.2; LR−, 0.03). The area under curve of the Mayo-modified, the GOG-99 and the ESMO-modified criteria was 0.763, 0.753, and 0.780, respectively. Conclusion: The ESMO-modified classification seems to be the risk-stratification model that most accurately predicts LN involvement in endometrioid EC clinically confined to the uterus. However, the Mayo-modified classification may be an alternative model to achieve a precise balance between the desire to prevent over-treatment and the ability to diagnose LN involvement.