检索结果-南通市图书馆

Investigating energy policies to boost grid-connected rooftop solar PV in Sudan

在线全文

学校读者我要写书评

暂无评论

Clean Energy 2023年第5期7卷 994-1005页

作者： Tarig Z.Ahmed Ayah mohamed Mawahib Eltayeb Ahmed Ahmed Osman Elamin Abdalgader mohamed g.Hassan-Sayed Cambridge Institute for Sustainability Leadership(CISL) University of CambridgeCambridgeCB21QAUK Energy and Climate Change Division Faculty of Engineering and Physical ScienceThe University of SouthamptonSouthamptonSO171BJUK Institute of Engineering Research and Material Technology National Centre for ResearchKhartoumSudan/University of KhartoumSudan University of California Davis1 Shields AveDavisCA 95616USA School of Chemistry Faculty of Engineering and Physical SciencesThe University of SouthamptonSouthamptonSO171BJUK

grid-connected rooftop solar photovoltaic(PV)systems can reduce the energy demand from the grid and significantly increase the power available to ***,rooftop solar PV has not yet been widely adopted in many sub-Saharan African countries,such as Sudan,although they are endowed with high solar radiation and in dire need of additional *** paper investigates risks and policies to increase grid-connected rooftop solar PV adoption in Sudan.A simplified United Nations Development Program Derisking Renewable Energy Investment framework is adopted to investigate this over three *** Stage 1,a list of risks and barriers was produced based on a literature review of solar PV studies in Sudan and interviews with nine *** was the risk most often mentioned(eight times from nine interviewees),followed by concerns about poor utility grid *** Stage 2,policy de-risking instruments and financial de-risking instruments were listed to overcome the *** include the intro-duction of net metering,the use of a third-party organization to monitor policy implementation,upgrade of the grid infrastructure,public awareness campaigns and energy-saving *** Stage 3,the levelized cost of electricity was estimated for a typical 2-kW rooftop PV system without policies(0.11$/kWh)and with a net-metering policy(0.07$/kWh).

关键词： energy policy rooftop solar PV Sudan energy poverty sustainable development photovoltaics

Microgrid dynamic security considering high penetration of renewable energy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Protection and Control of Modern Power Systems 2018年第1期3卷 245-255页

作者： g.Magdy Emad A.mohamed g.Shabib Adel A.Elbaset Yasunori Mitani1 Department of Electrical Engineering Kyushu Institute of TechnologyTobata-KuKitakyushu-shiFukuoka 804-8550Japan Department of Electrical Engineering Faculty of Energy EngineeringAswan UniversityAswan 81528Egypt Higher Institute of Engineering and Technology King MarriottAlexandria 23713Egypt Department of Electrical Engineering Faculty of EngineeringMinia UniversityMinia 61517Egypt

This paper presents a coordination strategy of Load Frequency Control(LFC)and digital frequency protection for an islanded microgrid(Mg)considering high penetration of Renewable Energy Sources(RESs).In such Mgs,the reduction in system inertia due to integration of large amount of RESs causes undesirable influence on Mg frequency stability,leading to weakening of the ***,sudden load events,and short circuits caused large frequency fluctuations,which threaten the system security and could lead to complete blackouts as well as damages to the system ***,maintaining the dynamic security in Mgs is one of the important challenges,which considered in this paper using a specific design and various data conversion stages of a digital over/under frequency relay(OUFR).The proposed relay will cover both under and over frequency conditions in coordination with LFC operation to protect the Mg against high frequency *** prove the response of the proposed coordination strategy,a small Mg was investigated for the *** proposed coordination method has been tested considering load change,high integration of ***,the sensitivity analysis of the presented technique was examined by varying the penetration level of RESs and reducing the system *** results reveal the effectiveness of the proposed coordination to maintain the power system frequency stability and *** addition,the superiority of the OUFR has been approved in terms of accuracy and speed response during high disturbances.

关键词： Digital frequency relay Load frequency control(LFC) Microgrid Renewable energy sources(RESs) Dynamic

Mineralogy,Chemical Characteristics and Upgrading of Beach Ilmenite of the Top Meter of Black Sand Deposits of the Kafr Al-Sheikh governorate,Northern Egypt

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta geologica Sinica(English Edition) 2017年第4期91卷 1326-1338页

作者： Abdel-Aal M. ABDEL-KARIM mohamed I. MOUSTAFA Adel H. EI-AFANDY mohamed g. BARAKAT Faculty of Science Zagazig University Egypt Engineering Colleges Northern Border University Saudi Arabia Nuclear Materials Authority P. O. Box 530 Maadi Cairo Egypt

Egyptian beach ilmenite occurs in a relatively high content in the naturally highly concentrated superficial black sand deposits at specific beach zones in the northern parts of the Nile Delta at Rosetta. Microscopic study shows that the ilmenite occurs as fresh homogeneous black or heterogeneous multicoloured altered grains and exhibits three types （homogeneous, exsolved and altered） of ilmenite varieties. XRD data of ilmenite indicates their association with minor hematite and quartz, whereas leucoxene shows its association with Nb-rutUe, pseudorutile and hematite. grain size distribution suggests a very fine sand size of 〉89% and 80% and a fine sand size of 10.5% and 18.3% for fresh and altered ilmenites, respectively. The density of fresh, altered ilmenite and leucoxene concentrates varies from 2.70, 2.50 to 2.40 ton/m^3, suggesting a gradual decrease from high grade fresh to leucoxene and consistent with variation in magnetic susceptibility as a consequence of the leaching of iron. Mass magnetic susceptibility reveals 97.6% of ilmenite and 92% of the altered form are obtained at 0.20 and 0.48 ampere. Fresh iimenite exhibits variable TiO2 （47.18%） and Fe2O3^T （46.10%） with minor MnO, MgO and Cr2O3 （1.22, 1.10 and 0.51%）. The altered ilmenite is higher in TiO2 （76.16%） and SiO2 （4.68%） and lower in Fe2O3^T （14.45%）, MnO, MgO and Cr2O3 （0.39, 0.52 and 0.11%） compared with the fresh form. Three concentrates of ilmenites （g1, g2 and g3） were prepared from crude ore using a Reading cross belt magnetic separator under different conditions, revealing a gradual increase of TiO2, SiO2, Al2O3 and CaO accompanied by a decrease of Fe2O3^T, MgO and Cr2O3 with repetition of the separation processes. Several ore dressing techniques were carried out to upgrade the iimenite concentrate.

关键词： Beach ilmenite mineralogy chemistry upgrading Northern Egypt

Composite Solid Rocket Propellant Based on gAP Polyurethane Matrix with Different Binder Contents

在线全文

学校读者我要写书评

暂无评论

火炸药学报 2020年第4期43卷 362-367页

作者： Islam KBoshra Ahmed Elbeih gUO Lin mohamed gZaki School of Chemistry and Environment Beihang UniversityBeijing 100191China Military Technical College Kobry ElkobbahCairoEgypt

Different gAP-based CSRP samples with different binder contents were prepared and compared with that of conventional HTPB *** crosslinker mixture of trimethylol propane(TMP)and butane diol(BD)was used in the gAP matrix beside the addition of dibutyltin dilaurate(DBTDL)to ensure cross-linking and curing completion of the prepared *** viscosity and hardness of all prepared formulations were monitored continuously during the curing *** mechanical characteristics of cured samples were *** burning rate at operating pressure and specific impulse were measured,while the theoretical specific impulse(I sp)was calculated by ICT code and compared with the measured *** to the results,DOA was found to be a suitable plasticizer for gAP when using in *** mechanical properties of CSRP with 25%gAP can produce the optimum mechanical behavior,which is close to that of HTPB-based *** optimum gAP-based formulation is one candidate to replace the traditional HTPB-based CSRP with high burning rate for some applications.

关键词： physical chemistry glycidyl azide polymer(gAP) hydroxyl terminated polybutadiene(HTPB) cross-linker mechanical properties

Enhancing fault-clearing algorithm for renewable-energy-based distribution systems using artificial neural networks

在线全文

学校读者我要写书评

暂无评论

Clean Energy 2024年第5期8卷 97-116页

作者： Rania g.mohamed M.A.Ebrahim Shady H.E.Abdel Aleem Electrical Engineering Department Institute of Aviation Engineering and TechnologyGiza12658Egypt Electrical Engineering Department Faculty of Engineering at ShoubraBenha UniversityCairo11629Egypt

Integrating small and large-scale photovoltaic(PV)solar systems into electrical distribution systems has become mandatory due to increased electricity bills and the concern for limiting greenhouse ***,the reliable and efficient operation of PV-based distribution systems can be confronted by the intermittence and high variability of solar sources and their consequential *** this regard,this article suggests a moderated fault-clearing strategy based on the incremental conductance–maximum power point tracking(IC–MPPT)technique and artificial neural networks(ANNs)to enhance fault detection,localization,and restoration pro-cesses in PV-based distribution *** proposed strategy leverages IC–MPPT to ensure optimal power generation from the PV solar system,even in the presence of *** tracking the maximum power point,the algorithm maintains the performance of the system and mitigates against the impact of faults on the output ***,an ANN is employed to improve fault detec-tion and localization *** developed ANN-based moderated fault-clearing strategy is trained using historical data and fault scenarios,enabling it to recognize fault patterns and make informed decisions through extensive simulations and comparisons with traditional fault-clearing *** accomplish this study,benchmarks in PV-based distribution systems are constructed and em-ployed using the MATLAB®/Simulink®software ***,to validate the efficacy of the developed ANN-based moderated fault-clearing strategy,a real case study of a 1-MW PV-based distribution system in an industrial field located in giza governorate,Egypt,is tested and *** obtained results demonstrate the effectiveness of the IC–MPPT and ANN-based moderated fault-clearing strategy in achieving faster fault detection,precise fault localization,and efficient restoration in PV solar-based dis-tribution systems while preserving maximum power extraction under small and larg

关键词： photovoltaic solar systems fault-clearing algorithm incremental conductance renewable energy artificial neural network maximum power point tracking

Hyperparameter Tuned Deep Learning Enabled Cyberbullying Classification in Social Media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第12期73卷 5011-5024页

作者： Mesfer Al Duhayyim Heba g.mohamed Saud S.Alotaibi Hany Mahgoub Abdullah mohamed Abdelwahed Motwakel Abu Sarwar Zamani mohamed I.Eldesouki Department of Computer Science College of Sciences and Humanities-AflajPrince Sattam bin Abdulaziz UniversitySaudi Arabia Department of Electrical Engineering College of EngineeringPrincess Nourah Bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia Department of Information Systems College of Computing and Information SystemUmm Al-Qura UniversitySaudi Arabia Department of Computer Science College of Science&Art at MahayilKing Khalid UniversityMuhayel AseerSaudi Arabia Faculty of Computers and Information Computer Science DepartmentMenoufia UniversityEgypt Research Centre Future University in EgyptNew Cairo11845Egypt Department of Computer and Self Development Preparatory Year DeanshipPrince Sattam bin Abdulaziz UniversityAl-KharjSaudi Arabia Department of Information System College of Computer Engineering and SciencesPrince Sattam bin Abdulaziz UniversityAl KharjSaudi Arabia

Cyberbullying(CB)is a challenging issue in social media and it becomes important to effectively identify the occurrence of *** recently developed deep learning(DL)models pave the way to design CB classifier models with maximum *** the same time,optimal hyperparameter tuning process plays a vital role to enhance overall *** study introduces a Teacher Learning genetic Optimization with Deep Learning Enabled Cyberbullying Classification(TLgODL-CBC)model in Social *** proposed TLgODL-CBC model intends to identify the existence and non-existence of CB in social media ***,the input data is cleaned and pre-processed to make it compatible for further *** by,independent recurrent autoencoder(IRAE)model is utilized for the recognition and classification of ***,the TLgO algorithm is used to optimally adjust the parameters related to the IRAE model and shows the novelty of the *** assuring the improved outcomes of the TLgODLCBC approach,a wide range of simulations are executed and the outcomes are investigated under several *** simulation outcomes make sure the improvements of the TLgODL-CBC model over recent approaches.

关键词： Social media deep learning cyberbullying cybersecurity hyperparameter optimization

Prediction of elastic and acoustic behaviors of calcarenite used for construction of historical monuments of Rabat, Morocco

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and geotechnical Engineering 2017年第1期9卷 74-83页

作者： Abdelaali Rahmouni Abderrahim Boulanouar Abderrahim Samaouali mohamed Boukalouch Yves géraud Jamal Sebbani Laboratory of Thermodynamics Department of Physics Faculty of Science Mohammed V University P.O. Box 1014 Rabat Morocco University of Lorraine ENSG UMR 7359-GeoRessources Nancy Cedex France

Natural materials(e.g. rocks and soils) are porous media, whose microstructures present a wide *** generally consist of a heterogeneous solid phase and a porous phase which may be fully or partially saturated with one or more fluids. The prediction of elastic and acoustic properties of porous materials is very important in many fields, such as physics of rocks, reservoir geophysics, civil engineering, construction field and study of the behavior of historical monuments. The aim of this work is to predict the elastic and acoustic behaviors of isotropic porous materials of a solid matrix containing dry, saturated and partially saturated spherical pores. For this, a homogenization technique based on the Morie Tanaka model is presented to connect the elastic and acoustic properties to porosity and degree of water saturation. Non-destructive ultrasonic technique is used to determine the elastic properties from measurements of P-wave velocities. The results obtained show the influence of porosity and degree of water saturation on the effective properties. The various predictions of Morie Tanaka model are then compared with experimental results for the elastic and acoustic properties of calcarenite.

关键词： Calcarenite Porous media Homogenization Morie Tanaka model Porosity Elastic properties Acoustic properties Degree of water saturation

Effect of suction process on the growth of a convective gas bubble in diver's tissues

在线全文

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2023年第2期16卷 177-197页

作者： Khaled g.mohamed Selim A.Mohammadein AhmedK.Abu-Nab Department of Mathematics Faculty of Science Banha UniversityBenhaEgypt Department of Mathematics Faculty of Science Tanta UniversityTantaEgypt Fluid Dynamics and Seismics Lab Moscow Institute of Physics and Technology Dolgoprudny Moscow region141700Russia Mathematics and Computer Science Department Faculty of ScienceMenoufia University Shebin El-Kom32511Egypt

The motivation of this research is to study the effect of suction process on a growing gas bubble and concentration distribution around this bubble in tissues of divers who surface too *** effect of bubble motion is also *** method of combined variables is used to solve the problem by combining the radial and time variables into one variable by using a suitable similarity transformation that enables to divide the diffusion equation into two ODEs,the first concerns to concentration distribution and the other concerns to the bubble radius *** resultant formulae are valid for both growth stages whenever the ambient pressure is variable at ascending of the diver,or constant as the diving stops or at *** effects of physical parameters are discussed when applying suction process and show that the dominant parameter is the initial void *** research findings reveal the role of suction process to activate the systemic blood circulation and delay the growth of gas bubbles in the tissues and reduce the incidence of decompression illness(DCI).This research also provides evidenceand agrees with the previous experimental studies to support the use of suction therapy to reduce the DCI harmful effects.

关键词： Nitrogen bubbles suction therapy void fraction method of combined variables decompression illness

Binary Oriented Feature Selection for Valid Product Derivation in Software Product Line

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2023年第9期76卷 3653-3670页

作者： Muhammad Fezan Afzal Imran Khan Javed Rashid Mubbashar Saddique Heba g.mohamed Department of CS&SE International Islamic UniversityIslamabad44000Pakistan Information Technology Services University of OkaraOkara56300Pakistan Departmet of Computer Science MLC LabOkara56300Pakistan Department of Computer Science&Engineering University of Engineering&Technology LahoreNarowal CampusNarowal51601Pakistan Department of Electrical Engineering College of EngineeringPrincess Nourah bint Abdulrahman UniversityP.O.Box 84428Riyadh11671Saudi Arabia

Software Product Line(SPL)is a group of software-intensive systems that share common and variable resources for developing a particular *** feature model is a tree-type structure used to manage SPL’s common and variable features with their different relations and problem of Crosstree Constraints(CTC).CTC problems exist in groups of common and variable features among the sub-tree of feature models more diverse in Internet of Things(IoT)devices because different Internet devices and protocols are ***,managing the CTC problem to achieve valid product configuration in IoT-based SPL is more complex,time-consuming,and ***,the CTC problem needs to be considered in previously proposed approaches such as Commonality VariabilityModeling of Features(COVAMOF)andgenarch+tool;therefore,invalid products are *** research has proposed a novel approach Binary Oriented Feature Selection Crosstree Constraints(BOFS-CTC),to find all possible valid products by selecting the features according to cardinality constraints and cross-tree constraint problems in the featuremodel of ***-CTC removes the invalid products at the early stage of feature selection for the product ***,this research developed the BOFS-CTC algorithm and applied it to,IoT-based feature *** findings of this research are that no relationship constraints and CTC violations occur and drive the valid feature product configurations for the application development by removing the invalid product *** accuracy of BOFS-CTC is measured by the integration sampling technique,where different valid product configurations are compared with the product configurations derived by BOFS-CTC and found 100%*** BOFS-CTC eliminates the testing cost and development effort of invalid SPL products.

关键词： Software product line feature model internet of things crosstree constraints variability management