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      • KCI등재

        Nonlinear Finite Element Model for the Optimization of Post-Tensioned One-Way Concrete Slab

        Abbas H. Mohammed,Dia Eddin Nassani,Nildem Tayşi,Ali K. Hussein 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.7

        Optimization in its wide sense can be used to solve many engineering problems and to find the best solutions so that designers cangain a maximum benefit from the available resources. In this research a nonlinear Finite Element (FE) model was developed for theoptimization of Unbonded Post-Tensioned (UPT) one-way slab. ANSYS program was used to find the optimum total weight of Post-Tensioned Tendon (PTT). In the optimization analysis, the objective function is the total weight of PTTs. The area of PTT, tendoninitial stress, and tendon eccentricity are considered as the design variables. Concrete normal stress, steel tendon stress, concrete shearstress, and mid-span deflection of concrete slab are considered as constraints. The optimization result indicates that the total weight ofPTTs can be reduced about 33% for the UPT slabs using an appropriate optimization algorithm.

      • KCI등재

        Modelling of bonded and unbonded post-tensioned concrete flat slabs under flexural and thermal loading

        Abbas H. Mohammed,Nildem Tayşi 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.5

        During their life span, post-tensioned concrete structures may be exposed to thermal loads. Therefore, there has been a growing interest in research on the advanced analysis and design of post-tensioned concrete slabs subjected to thermal loads. This paper investigates the structural behaviour of post-tensioned one-way spanning concrete slabs. A nonlinear finite element model for the analysis of post- tensioned unbonded and bonded concrete slabs at elevated temperatures was developed. The interface between the tendon and surrounding concrete was also modelled, allowing the tendon to retain its profile shape during the deformation of the slab. The load-deflection behaviour, load-force behaviour in the tendon, and the failure modes are presented. The numerical analysis was conducted by the finite element ANSYS software and was carried out on two different one-way concrete slabs chosen from literature. A parametric study was conducted to investigate the effect of several selected parameters on the overall behavior of post-tensioned one-way concrete slab. These parameters include the effect of tendon bonding, the effect of thermal loading and the effect of tendon profile. Comparison between uniform thermal loading and non-uniform thermal loading showed that restrained post tensioned slab with bottom surface hotter has smaller failure load capacity.

      • KCI등재

        ANFIS Based Reinforcement Learning Strategy for Control A Nonlinear Coupled Tanks System

        Mary Ali Hussien,Miry Abbas H.,Miry Mohammed H. 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.3

        In this paper, a novel algorithm based machine learning technique for control nonlinear coupled tanks system is presented. An intelligent controller using adaptive neuro-fuzzy inference system (ANFIS) based reinforcement learning is proposed (ANFIS-RL) by representing the nonlinear coupled tanks system as a Markov decision process. A model-free learning algorithm has been used to train a policy that controls the liquid level of the tanks system without the need to determine the dynamic model of the controlled system. Based on the optimal learned policy, which is approximated by ANFIS, the controlled system can perform the best action quickly based on the states of the system. Simulation results demonstrated the feasibility of the proposed algorithm.

      • KCI등재

        Comparison of tooth movement and biological response in corticotomy and micro-osteoperforation in rabbits

        Junghan Kim,Yoon-Ah Kook,Mohamed Bayome,Jae Hyun Park,Won Lee,Hojae Choi,Noha H. Abbas 대한치과교정학회 2019 대한치과교정학회지 Vol.49 No.4

        Objective: The aim of this study was to evaluate the amount of tooth movement and histologic changes with different corticotomy designs and micro-osteoperforation in rabbits. Methods: The sample consisted of 24 rabbits divided into three experimental groups (triangular corticotomy [TC] and indentation corticotomy [IC] with flap, and flapless micro-osteoperforations [MP]) and a control. A traction force of 100 cN was applied by connecting the first premolars to the incisors. The amount of tooth movement was measured. Kruskal–Wallis test was used to assess differences in tooth movement between the groups. Micro-computed tomography, hematoxylin and eosin staining, and tartrate-resistant acidic phosphatase (TRAP) analysis were performed. Analysis of variance was applied to assess differences in TRAP-positive osteoclast count between the groups. Results: The amount of tooth movement increased by 46.5% and 32.0% in the IC and MP groups, respectively, while the bone fraction analysis showed 69.7% and 8.5% less mineralization compared to the control. There were no significant intergroup differences in the number of TRAPpositive osteoclasts. Conclusions: The micro-osteoperforation group showed no significant differences in the amount of tooth movement compared to the corticotomy groups, nor in the TRAP-positive osteoclast count compared to both corticotomy groups and control.

      • Response of Triple Negative Breast Cancer to Neoadjuvant Chemotherapy: Correlation between Ki-67 Expression and Pathological Response

        Elnemr, Gamal M,El-Rashidy, Ahmed H,Osman, Ahmed H,Issa, Lotfi F,Abbas, Osama A,Al-Zahrani, Abdullah S,El-Seman, Sheriff M,Mohammed, Amrallah A,Hassan, Abdelghani A Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.2

        Triple-negative breast cancers constitute about 15% of all cases, but despite their higher response to neoadjuvant chemotherapy, the tumors are very aggressive and associated with a poor prognosis as well as a higher risk of early recurrence. This study was retrospectively performed on 101 patients with stage II and III invasive breast cancer who received 6-8 cycles of neo-adjuvant chemotherapy. Out of the total, 23 were in the triple negative breast cancer subgroup. Nuclear Ki-67 expression in both the large cohort group (n=101) and triple negative breast cancer subgroup (n=23) and its relation to the pathological response were evaluated. The purpose of the study was to identify the predictive value of nuclear protein Ki-67 expression among patients with invasive breast cancers, involving the triple negative breast cancer subgroup, treated with neoadjuvant chemotherapy in correlation to the rate of pathological complete response. The proliferation marker Ki-67 expression was highest in the triple negative breast cancer subgroup. No appreciable difference in the rate of Ki-67 expression in triple negative breast cancer subgroup using either a cutoff of 14% or 35%. Triple negative breast cancer subgroup showed lower rates of pathological complete response. Achievement of pathological complete response was significantly correlated with smaller tumor size and higher Ki-67 expression. The majority of triple negative breast cancer cases achieved pathological partial response. The study concluded that Ki-67 is a useful tool to predict chemosensitivity in the setting of neoadjuvant chemotherapy for invasive breast cancer but not for the triple negative breast cancer subgroup.

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