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.

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.

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

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.

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.

Testicular Biopsy Histopathology as an Indicator of Successful Restoration of Spermatogenesis after Varicocelectomy in Non-obstructive Azoospermia

Hamdy Abdelmawla Aboutaleb,Eid Abdel-Rasoul Elsherif,Mohammed Kamal Omar,Tarek Mohammed Abdelbaky 대한남성과학회 2014 The World Journal of Men's Health Vol.32 No.1

Purpose: We aimed to evaluate the efficacy of using testicular biopsy histopathology as an indicator of the success of loupe-assisted subinguinal varicocelectomy in non-obstructive azoospermia (NOA) patients.Materials and Methods: In a 2-year period, a prospective study was carried at Minoufiya University Hospital on 20 NOA patients with clinical bilateral varicoceles. These patients underwent loupe-assisted subinguinal varicocelectomy with simultaneous testicular biopsy. All patients were evaluated by determining their hormonal profile and performing semen analyses and scrotal Doppler and transrectal ultrasonography. Two semen analyses showing azoospermia were performed before the surgery and two semen analyses were received at 3 and 6 months post-operatively for follow-up.Results: The mean age was 29.9±6.7 years, and the mean follow-up duration was 17.3±8.3 months. We noted the restoration of spermatogenesis in six men (30% of all patients). Testicular biopsy results were as follows: hypospermatogenesis in 7 patients, maturation arrest in 3, and Sertoli cell-only syndrome in 10. The improvement in the sperm counts of these patients ranged from 3 million to 15 million/mL. Sperms were recovered in the hypospermatogenesis (6 patients, 85.5%) patients only, but other patients with testicular biopsy results of Sertoli cell-only or maturation arrest did not show any improvement in their semen parameters. Conclusions: Testicular biopsy results showed that hypospermatogenesis patients have a better chance of improvement in their semen analysis after varicocelectomy in contrast to NOA patients with Sertoli cell-only syndrome or maturation arrest.

Modified models predicting punching capacity of edge column-slab joints considering different codes

Hamdy A. Elgohary,Mohamed A. El Zareef 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.4

Significant changes have been made to estimate the punching shear capacity for edge column-slab joints in the latest editions of most current codes. The revised equations account for axial forces as well as moments conveyed to columns from slabs, which have a substantial impact on the punching resistance of such joints. Many key design parameters, such as reinforcement-ratio, concrete strength, size-effect, and critical-section perimeter, were treated differently or even ignored in various code provisions. Consequently, wide ranges of predicted punching shear strength were detected by applying different code formulas. Therefore, it is essential to assess the various current Codes’ design-equations. Because of the similarity in estimated outcomes, only the ACI, EC, and SNiP are used in this study to cover a wide range of estimation ranges from highly conservative to unconservative. This paper is devoted to analyzing the techniques in these code provisions, comparing the estimated punching resistance with available experimental data, and finally developing efficient models predicting the punching capacity of edge column-slab connections. 63 samples from past investigations were chosen for validation. To appropriately predict the punching shear, newly updated equations for ACI and SNiP are provided based on nonlinear regression analysis. The proposed equations’ results match the experimental data quite well.

Preparation and characterization of controlled-release doxazosin mesylate pellets using a simple drug layering-aquacoating technique

Hamdy Abdelkader,Heba A. Hazzah,Magda A. EL-Massik,Ossama Y. Abdallah 한국약제학회 2013 Journal of Pharmaceutical Investigation Vol.43 No.4

Pellets are one of multiparticulate pharmaceutical forms and can offer numerous technical and biopharmaceutical advantages compared with single dose unit formulations, e.g. tablets and capsules. This study aimed at formulation of controlled-release pellets of doxazosin mesylate (DM), a widely used treatment for antihypertensive and benign prostatic hyperplasia. DM was loaded onto microcrystalline cellulose CELLETS pellets using hydroalcoholic solution and alcoholic suspension layering techniques to achieve a minimum drug load of 4 mg DM/g pellets. DM-layered CELLETS were coated by Aquacoat dispersion (ready-made ethylcellulose dispersion) using a coating pan technique as a simple and widely utilized technique in pharmaceutical industry. Controlled-release DM-layered pellets showed a release profile comparable to the controlled-release commercial product Cardura XL Tablet. Also, the mechanism of DM release from Aquacoat CELLETS was mathematically modeled and imaged by scanning electron microscopy to elucidate drug release mechanisms from the prepared pellet formulations. Accelerated stability studies of the prepared pellets were performed under stress conditions of 40 C, and 75 % RH for 3 months. In conclusion, preparation of controlledrelease DM-layered CELLETS is feasible using a simple and conventional coating pan technology.

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.

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.