CAD model simplification using a removing details and merging faces technique for a FEM simulation

Hamdi Mounir,Aifaoui Nizar,Benamara Abdelmajid 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.11

The simulation process is currently used in the design and dimensioning of mechanical parts. With the progress of computer materials,the finite elements method (FEM) becomes the most used approach in the simulation of mechanical behaviour. The simulation process needs multiple Design-FEM loops. In order to accelerate those analysis loops, an adaptation of computer aided design (CAD) model is necessary. The adaptation step consists in the simplification of the CAD model geometry by eliminating details (holes, chamfers, fillet,etc.) and faces. In this paper, a novel technique of simplification of the CAD geometry is developed. This technique is a hybrid method based on a combination of the elimination details and merging faces. The merging of faces is based on the energetic method. With this approach, the computing time is reduced by the elimination of geometric details which do not boundary conditions. An implementation of the proposed algorithm on the Open Cascade platform is also presented. The results of the developed method are compared with a previous publication. The reduction of the computing time and the amelioration of the result precision highlight the efficiency of the presented method.

GRADED PRIMITIVE AND INC-EXTENSIONS

Hamdi, Haleh,Sahandi, Parviz Korean Mathematical Society 2018 대한수학회논문집 Vol.33 No.2

It is well-known that quasi-$Pr{\ddot{u}}fer$ domains are characterized as those domains D, such that every extension of D inside its quotient field is a primitive extension and that primitive extensions are characterized in terms of INC-extensions. Let $R={\bigoplus}_{{\alpha}{{\in}}{\Gamma}}$ $R_{\alpha}$ be a graded integral domain graded by an arbitrary torsionless grading monoid ${\Gamma}$ and ${\star}$ be a semistar operation on R. The main purpose of this paper is to give new characterizations of gr-${\star}$-quasi-$Pr{\ddot{u}}fer$ domains in terms of graded primitive and INC-extensions. Applications include new characterizations of UMt-domains.

UPPERS TO ZERO IN POLYNOMIAL RINGS OVER GRADED DOMAINS AND UMt-DOMAINS

Hamdi, Haleh,Sahandi, Parviz Korean Mathematical Society 2018 대한수학회보 Vol.55 No.1

Let $R={\bigoplus}_{{\alpha}{\in}{\Gamma}}\;R_{\alpha}$ be a graded integral domain, H be the set of nonzero homogeneous elements of R, and ${\star}$ be a semistar operation on R. The purpose of this paper is to study the properties of $quasi-Pr{\ddot{u}}fer$ and UMt-domains of graded integral domains. For this reason we study the graded analogue of ${\star}-quasi-Pr{\ddot{u}}fer$ domains called $gr-{\star}-quasi-Pr{\ddot{u}}fer$ domains. We study several ring-theoretic properties of $gr-{\star}-quasi-Pr{\ddot{u}}fer$ domains. As an application we give new characterizations of UMt-domains. In particular it is shown that R is a $gr-t-quasi-Pr{\ddot{u}}fer$ domain if and only if R is a UMt-domain if and only if RP is a $quasi-Pr{\ddot{u}}fer$ domain for each homogeneous maximal t-ideal P of R. We also show that R is a UMt-domain if and only if H is a t-splitting set in R[X] if and only if each prime t-ideal Q in R[X] such that $Q{\cap}H ={\emptyset}$ is a maximal t-ideal.

Physicochemical Impact of Irrigation with Treated Wastewater on Soil: Case Study of Cebala BorjTouil Perimeter (tunisia)

Hamdi Sahraoui,Khawla Khaskhoussy,Mohamed Hachicha 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Stability Analysis and Memory Control Design of Polynomial Fuzzy Systems with Time Delay via Polynomial Lyapunov-Krasovskii Functional

Hamdi Gassara,Ahmed El Hajjaji,Mohamed Krid,Mohamed Chaabane 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper investigates the problems of delay-dependent stability analysis and memory control design of polynomial fuzzy systems with time delay. Using polynomial Lyapunov-Krasovskii functional and slack polynomial matrix variables, delay dependent sufficient stability and stabilizability conditions are derived in terms of sum of squares (SOS) which can be numerically (partially symbolically) solved via the recently developed SOSTOOLS. The main advantage of the proposed design is the reduction of conservatism for three great reasons. The first one is that polynomial matrices are not only dependent on the system state vector but also on the state vector with time delay. The second one is that the design conditions are formulated in delay dependent SOS. It is well known that the delay-dependent conditions are less conservative than those independent of time delay. The third one is that only correlated terms are used in the design of SOS. The simulation and comparison are given to illustrate the lesser conservativeness of the proposed result.

Beam finite element model of a vibrate wind blade in large elastic deformation

Hamdi, Hedi,Farah, Khaled Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

This paper presents a beam finite element model of a vibrate wind blade in large elastic deformation subjected to the aerodynamic, centrifugal, gyroscopic and gravity loads. The gyroscopic loads applied to the blade are induced by her simultaneous vibration and rotation. The proposed beam finite element model is based on a simplex interpolation method and it is mainly intended to the numerical analysis of wind blades vibration in large elastic deformation. For this purpose, the theory of the sheared beams and the finite element method are combined to develop the algebraic equations system governing the three-dimensional motion of blade vibration. The applicability of the theoretical approach is elucidated through an original case study. Also, the static deformation of the used wind blade is assessed by appropriate software using a solid finite element model in order to show the effectiveness of the obtained results. To simulate the nonlinear dynamic response of wind blade, the predictor-corrector Newmark scheme is applied and the stability of numerical process is approved during a large time of blade functioning. Finally, the influence of the modified geometrical stiffness on the amplitudes and frequencies of the wind blade vibration induced by the sinusoidal excitation of gravity is analyzed.

Modeling and optimization of hard turning of X38CrMoV5-1 steel with CBN tool: Machining parameters effects on flank wear and surface roughness

Hamdi Aouici,Mohamed Athmane Yallese,Brahim Fnides,Kamel Chaoui,Tarek Mabrouki 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.11

The present study, aims to investigate, under turning conditions of hardened AISI H11 (X38CrMoV5-1), the effects of cutting parameters on flank wear (VB) and surface roughness (Ra) using CBN tool. The machining experiments are conducted based on the response surface methodology (RSM). Combined effects of three cutting parameters, namely cutting speed, feed rate and cutting time on the two performance outputs (i.e. VB and Ra), are explored employing the analysis of variance (ANOVA). Optimal cutting conditions for each performance level are established and the relationship between the variables and the technological parameters is determined using a quadratic regression model. The results show that the flank wear is influenced principally by the cutting time and in the second level by the cutting speed. Also, it is that indicated that the feed rate is the dominant factor affecting workpiece surface roughness.

A Unified Frame Work for Discrete Event Systems

Hamdi A. Awad 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.5

Early fault detection and isolation minimize cost and processing time of industrial systems. The main purpose of this paper is to introduce a novel delta-marking idea to design a generalized interpreted Petri net-based fault detection and isolation scheme (IPN-based diagnoser) for all PN models. This idea overcomes the event detectability problem that restricts the performance of the conventional dignosers to certain types of Petri net model. Furthermore, a unified framework for a discrete event system that comprises a PN-based model, a PN-based supervisor, and a PN-based diagnoser of a proc-ess under consideration, is built in this paper. In addition, this paper addresses some issues for industrial systems modeling and supervision. A rapid thermal process (RTP) is used as an industrial process to test the proposed unified framework after revising its PN-model. This scheme is not only developed for RTPs, but also can be employed for industrial processes with certain modifications depending on the nature of their structures. Simulation results have confirmed the effectiveness of the proposed unified framework.

Effect of smear layer deproteinization on bonding of self-etch adhesives to dentin: a systematic review and meta-analysis

Hamdi H. H. Hamama 대한치과보존학회 2018 Restorative Dentistry & Endodontics Vol.43 No.2

Objectives The aim of this systematic review was to critically analyze previously published studies of the effects of dentin surface pretreatment with deproteinizing agents on the bonding of self-etch (SE) adhesives to dentin. Additionally, a meta-analysis was conducted to quantify the effects of the above-mentioned surface pretreatment methods on the bonding of SE adhesives to dentin. Materials and Methods An electronic search was performed using the following databases: Scopus, PubMed and ScienceDirect. The online search was performed using the following keywords: ‘dentin’ or ‘hypochlorous acid’ or ‘sodium hypochlorite’ and ‘self-etch adhesive.’ The following categories were excluded during the assessment process: non-English articles, randomized clinical trials, case reports, animal studies, and review articles. The reviewed studies were subjected to meta-analysis to quantify the effect of the application time and concentration of sodium hypochlorite (NaOCl) and hypochlorous acid (HOCl) deproteinizing agents on bonding to dentin. Results Only 9 laboratory studies fit the inclusion criteria of this systematic review. The results of the meta-analysis revealed that the pooled average microtensile bond strength values to dentin pre-treated with deproteinizing agents (15.71 MPa) was significantly lower than those of the non-treated control group (20.94 MPa). Conclusions In light of the currently available scientific evidence, dentin surface pretreatment with deproteinizing agents does not enhance the bonding of SE adhesives to dentin. The HOCl deproteinizing agent exhibited minimal adverse effects on bonding to dentin in comparison with NaOCl solutions.

Durable Response of Androgen Receptor-Positive Male Breast Cancer to Goserelin

Hamdy Abdel Azim,Loay Kassem,Kyrillus Samaan Shohdy,Boules Eshaak,Shady Elia Anis,Nermine Shawky Kamal 한국유방암학회 2019 Journal of breast cancer Vol.22 No.1

The luteinizing hormone-releasing hormone/androgen receptor (LHRH/AR) pathway is a promising treatment target in a subgroup of female patients with triple-negative breast cancer (TNBC). However, very little is known about the efficacy of this strategy in male patients with TNBC. In this report, we describe a male patient with AR-positive TNBC who was successfully treated using an LHRH agonist after pretreatment with several lines of chemotherapy and achieved a durable response. We also review the existing evidence supporting LHRH- and AR-targeted therapy for this rare disease.