Detailed Design Procedures for PMSG Direct-Driven by Wind Turbines

Ahmed Hebala,Walid A. M. Ghoneim,Hamdy A. Ashour 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.1

This paper is committed to show a well-ordered system used to design a permanent magnet synchronous generator (PMSG). The fundamental focus of this work is the generators which are in gearless configuration, and in the fragmentary or couple of kilowatts power range. A straight lumped-component based model is introduced, which is utilized for fundamental investigation and design. Later, a proposed comprehensive design strategy—stated with conditions, tables, design limits and practical recommendations—are presented in full details. Likewise, a flowchart is created to be later used as a Matlab M-File code for PMSG design. The outlined strategies are then authenticated through three case studies while being compared to the result from Finite Element Method (FEM) of Maxwell package. The three case studies are firstly, comparing the effectiveness of the procedures with a PMSG presented in literature. Secondly compared to a generator from the market. And finally using the procedure to implement a 1 kw prototype generator and validate the results with it. Such comparisons have validated the proposed procedures as a contributed step-by-step simple and reliable design tool for such cluster of PMSGs.

Highly efficient and reusable superhydrophobic/superoleophilic polystyrene@ Fe₃O₄ nanofiber membrane for high-performance oil/water separation

Moatmed, Sara M.,Khedr, Mohamed Hamdy,El-dek, S.I.,Kim, Hak-Yong,El-Deen, Ahmed G. Elsevier 2019 Journal of environmental chemical engineering Vol.7 No.6

<P><B>Abstract</B></P> <P>Due to increasing of oil spills and high organic contamination of marine environment, developing of cost-effective and rapid oil/water separation technique has become inevitable. Herein, freestanding and flexible hybrid polystyrene nanofibers are introduced as highly efficient hybrid membrane for ultrafast oil/water separation without external pressure. Typically, different loading of Fe<SUB>3</SUB>O<SUB>4</SUB> nanoparticles embedded into polystyrene nanofibers using electrospinning to fabricate superhydrophobic/super-oleophilic membrane. The morphological shape, crystal structure and surface wettability behavior were elucidated by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and contact angel, respectively. The optimum loading of magnetite nanoparticles into the nanofiber membranes was investigated to achieve best separation performance. The obtained results demonstrated that the incorporation of (Fe<SUB>3</SUB>O<SUB>4</SUB>) nanoparticles into membrane has a significant impact for enhancing superhydrophobic properties and the separation efficiency against light and heavy oils. Among all formulations, the fabricated (PS@Fe<SUB>3</SUB>O<SUB>4</SUB>10 wt.%) membrane revealed ultrahigh flux (5000 L m<SUP>−2</SUP> h<SUP>−1</SUP>) with separation efficiency of 99.8 % for hexane under gravity driven process and excellent superhydrophobicity with water contact angle 162° moreover excellent reusability 98.5 % for 50 consecutive cycles. Interestingly, the proposed hybrid nanofiber membrane achieved distinct separation efficiencies 95 % and 92 % for food oils such as olive oil and sesame oil. Overall, the current study provides cost-effective and facile approach to distinctly improve the membrane performance for durable oil/water separation technique.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Theoretical rotational stiffness of the flexible base connection based on parametric study via the whale optimization algorithm

Mahmoud T. Nawar,Ehab B. Matar,Hassan M. Maaly,Ahmed G. Alaaser,Osman Hamdy 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.1

This paper handles the results of an extensive parametric study on the rotational stiffness of the flexible base connection using ABAQUS program. The results of the parametric study show the relation between the applied moment and the relative rotation for 96 different base connections. The configurations of the studied connections considered different numbers, diameters, and spacing of the anchor bolts along with different thicknesses of the base plate to investigate the effect of these parameters on the rotational stiffness behavior. The results of the previous parametric research used through the whale optimization algorithm (WOA) to detect different equation formulation of the moment-rotation (M-Ɵr) equation to detect optimum equation simulates the general nonlinear rotational behavior of the flexible base connection considering all variables used in the parametric study. WOA is a relatively new promising algorithm, which is used in different types of optimization problems. For more verification, the classical genetic algorithm (GA) is used to make a comparison with WOA results. The results show that WOA is capable of getting an optimum equation of the M-Ɵr relation, which can be used to simulate the actual rotational stiffness of the flexible base connections. The rotational stiffness at H/150 can be calculated using WOA (1) method and be used as a design aid for engineering design.

Proposed program for monitoring recent Crustal movement in Korean Peninsula

Hamdy, Ahmed M.,Jo, Bong-Gon Korean Society of Earth and Exploration Geophysici 2002 지구물리 Vol.5 No.4

한반도는 동아시아 활성 경계부의 끝에 위치해있다. 한반도에서의 지진 활동은 이웃나라인 중국과 일본에 비해서 상대적으로 낮은 편이다. 한반도에서의 지진정보에 따르면 한반도는 지진재해로부터 완전히 안전하지는 않다. 게다가, 한반도 주위의 "태평양, 필리핀해, 유라시아, 남중국"같은 구조적 판들의 상대적인 움직임의 결과로 생긴 다양한 구조적 힘에 의해 둘러 싸여져 있다. 현재 남한에는 5개의 정부기관에서 서로의 필요에 따라 설치한 65개의 GPS관측소를 가지고 있다. 한반도에서의 지진피해를 최소화하기 위해 현재, 앞서 언급한 지진관측소 중 몇 개의 관측소로부터의 GPS관측 자료와 한반도 내부와 주변부의 구조적 환경들을 함께 고려하여 근대의 지각운동을 관찰하는 프로그램이 계획되어 왔다. 이 프로그램은 두개의 주요 부분으로 이루어져 있으며, 첫째부분은 주변 국가인 "중국, 일본"과 협력하여 한반도 주위의 지각 변형을 모니터링하기 위한 것인데, 이 부분은 "East Sea Phase and Yellow Sea Phase" 두개의 페이스로 구성되어 있다 이러한 페이스들은 "East Sea Phase and Yellow Sea Phase"에서 각각의 변형 파라미터들을 결정하는데 도움을 줄 것이다. 한편, 이 프로그램의 두번째 부분은 한반도 주요 단층 내부와 주변의 변형 파라미터와 한반도-제주도 간의 상대운동을 결정하기 위해 계획되었다. 이번 연구를 통해서 다양한 지구 역학적 방법의 적용을 위한 신빙성 있는 자료로서 사용되기 위해, 앞서 언급한 관측소에서의 지각운동 중심부에서 기록된 자료의 필요성이 부각되었다. The Korean peninsula is located at the edge of the East Asian active margin. The seismic activity in the Korean Peninsula is relatively low compared with the neighboring countries China and Japan. According to the available Seismic information, the Korean Peninsula is not totally safe from the Earthquake disaster. Moreover, the area is surrounded by varies tectonic forces which is resulted from the relative movements of the surrounding tectonic plates "Pacific, Philippine Sea, Eurasian and South China". Nowadays South Korea has 65 GPS stations belong to 5 governmental organizations "each organization figure out its own GPS stations for different requirements" In order to minimize the seismic hazard in the Korean Peninsula a program for monitoring the recent crustal movement has been designed considering the uses of the available GPS station "some selected stations from the previously mentioned stations" and the tectonic settings in and around the Korean Peninsula. This program is composed of two main parts, the first part to monitor the crustal deformation around the Korean Peninsula with the collaboration of the surrounding countries "China and Japan" this part is composed of two phases "East Sea Phase and Yellow Sea Phase". These phases will be helpful in determining the deformation parameters in the East Sea and the Yellow Sea respectively While the Second part of this program, is designed to determine the deformation parameters id and around the main faults in the Korean Peninsula and the relative movement between the Korean Peninsula and the Cheju Island. Through out this study the needs of crustal movement center rose up to collect the data from the previously mentioned stations and Organizations in order to use such reliable data in different geodynamical application.

Preliminary crustal movement study around the Honam shear zone and Okchon Belt (South Korea) using GPS observations

Ahmed M. Hamdy,Pil-Ho Park,Bong Gon Jo 한국지질과학협의회 2004 Geosciences Journal Vol.8 No.1

Crustal movement around the Honam shear zone and the Okchon Belt was estimated by using five GPS stations data. The data had been collected from two campaigns; each of them had five days long continuous observation and separated by one-year time span. The average velocity in this area is less than 2.4 mm/year and the depicted strain is less than 0.053 micro-strain/ year. The fault line structure together with the principal axis of compression was used to determine the nature of strain and the direction of movements; the results demonstrate the presence of relative movement between the Okchon Belt and its surrounding blocks “Yeongnam Massif and Kyonggi Massif”. In spite of the fact that these results are obtained from one-year time span, they suggest the presence of relative movement between Okchon Belt and its surrounding massifs.

Buckling and bending of coated FG graphene-reinforced composite plates and shells

Ahmed Amine Daikh,Amin Hamdi,Hani M. Ahmed,Mohamed S. Abdelwahed,Alaa A. Abdelrahman,Mohamed A. Eltaher Techno-Press 2023 Advances in nano research Vol.15 No.2

The advancement of theoretical research has numerous challenges, particularly with regard to the modeling of structures, in contrast to experimental investigation of the mechanical behavior of complex systems. The main objective of this investigation is to provide an analytical analysis of the static problem of a new generation of composite structure, namely, functionally graded FG graphene reinforced composite GRC coated plates/shells. A complex power law function is used to define the material's graduation. Investigations are conducted on Hardcore and Softcore coated FG plates/shells. The virtual work approach is used to perform the equilibrium equations, which are then solved using the Galerkin technique to account for various boundary conditions. With reliable published articles, the presented solution is validated. The effects of hardcore and softcore distributions, gradation indexes, and boundary conditions on the buckling, bending deflection and stresses of FG GRC-coated shells are presented in detail. Obtained results and the developed procedure are supportive for design and manufacturing of FG-GRC coated plates/shells in several fields and industries e.g., aerospace, automotive, marine, and biomedical implants.

Euler-Maruyama Numerical solution of some stochastic functional differential equations

( Hamdy M. Ahmed ) 한국산업응용수학회(구 한국산업정보응용수학회) 2007 한국산업정보응용수학회 Vol.11 No.1

Proposed program for monitoring recent Crustal movement in Korean Peninsula

( Ahmed M. Hamdy ),( Bong Gon Jo ) 대한지구물리학회 2002 지구물리 Vol.5 No.4

Advantage of Using Free Network Adjustment Technique in the Crustal Movement Monitoring Geodetic Networks

( Ahmed M. Hamdy ),( Bong Gon Jo ) 대한지구물리학회 2003 지구물리 Vol.6 No.1

EULER-MARUYAMA METHOD FOR SOME NONLINEAR STOCHASTIC PARTIAL DIFFERENTIAL EQUATIONS WITH JUMP-DIFFUSION

HAMDY M. AHMED 한국산업응용수학회 2014 Journal of the Korean Society for Industrial and A Vol.18 No.1

In this paper we discussed Euler-Maruyama method for stochastic differential equations with jump diffusion. We give a convergence result for Euler-Maruyama where the coefficients of the stochastic differential equation are locally Lipschitz and the pth moments of the exact and numerical solution are bounded for some p> 2.