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Dynamic Interaction Analysis of Coupled Axial-Torsional-Lateral Mechanical Vibrations in Rotary Drilling Systems

Structural Durability & Health Monitoring 2025年第1期19卷 77-103页

作者： Sabrina Meddah sid ahmed tadjer Abdelhakim Idir Kong Fah Tee Mohamed Zinelabidine Doghmane Madjid Kidouche Applied Automation Laboratory Faculty of Hydrocarbons and ChemistryUniversity of BoumerdesBoumerdes35000Algeria Institute of Electrical and Electronic Engineering(IGEE) University of BoumerdesBoumerdes35000Algeria Laboratory of the Electrification of Industrial Enterprises University of BoumerdesBoumerdes35000Algeria Electrical Engineering Department Mohamed Boudiaf University of M’silaM’sila28000Algeria Department of Civil and Environmental Engineering King Fahd University of Petroleum&MineralsDhahran31261Saudi Arabia Interdisciplinary Research Center for Construction and Building Materials King Fahd University of Petroleum&Minerals(KFUPM)Dhahran31261Saudi Arabia

Maintaining the integrity and longevity of structures is essential in many industries,such as aerospace,nuclear,and *** achieve the cost-effectiveness of large-scale systems in petroleum drilling,a strong emphasis on structural durability and monitoring is *** study focuses on the mechanical vibrations that occur in rotary drilling systems,which have a substantial impact on the structural integrity of drilling *** study speciﬁcally investigates axial,torsional,and lateral vibrations,which might lead to negative consequences such as bit-bounce,chaotic whirling,and high-frequency *** events not only hinder the efﬁciency of drilling but also lead to exhaustion and harm to the system’s components since they are difﬁcult to be detected and controlled in real *** study investigates the dynamic interactions of these vibrations,speciﬁcally in their high-frequency modes,usingﬁeld data obtained from measurement while ***ﬁndings have demonstrated the effect of strong coupling between the high-frequency modes of these vibrations on drilling sys-tem *** obtained results highlight the importance of considering the interconnected impacts of these vibrations when designing and implementing robust control ***,integrating these compo-nents can increase the durability of drill bits and drill strings,as well as improve the ability to monitor and detect ***,by exploiting theseﬁndings,the assessment of structural resilience in rotary drilling systems can be ***,the study demonstrates the capacity of structural health monitoring to improve the quality,dependability,and efﬁciency of rotary drilling systems in the petroleum industry.

关键词： Rotary drilling systems mechanical vibrations structural durability dynamic interaction analysis ﬁeld data analysis

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SOME PROPERTIES OF m-ISOMETRIES AND m-INVERTIBLE OPERATORS ON BANACH SPACES

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Acta Mathematica Scientia 2012年第2期32卷 520-530页

作者： Ould ahmed Mahmoud sid ahmed Department of Mathematics College of ScienceAljouf UniversityAljouf 2014Saudi Arabia

This article has two purposes： the first is to give some structure results for the class of m-isometries, and the second purpose is to extend the notions of left and right inverses to m-left and m-right inverses resp... 详细信息

关键词： m-isometry m-left inverse m-right inverse approximate spectrum pointspectrum

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A robust model-free controller for a three-phase grid-connected photovoltaic system based on ultra-local model

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Protection and Control of Modern Power Systems 2021年第1期6卷 538-550页

作者： Ahsene Boubakir sid-ahmed Touil Salim Labiod Nasserdine Boudjerda LAJ Faculty of Science and TechnologyUniversity of JijelBP.98Ouled Aissa18000JijelAlgeria Department of Electrical Engineering University of JijelJijelAlgeria LER Faculty of Sciences and TechnologyUniversity of JijelBP 98Ouled Aissa18000JijelAlgeria

In this paper, a robust model-free controller for a grid-connected photovoltaic (PV) system is designed. The system consists of a PV generator connected to a three-phase grid by a DC/AC converter. The control objectives of the overall system are to extract maximum power from the PV source, to control reactive power exchange and to improve the quality of the current injected into the grid. The model-free control technique is based on the use of an ultra-local model instead of the dynamic model of the overall system. The local model is continuously updated based on a numerical differentiator using only the input–output behavior of the controlled system. The model-free controller consists of a classical feedback controller and a compensator for the effects of internal parameter changes and external disturbances. Simulation results illustrate the efficiency of the controller for grid-connected PV systems.

关键词： Photovoltaic system Maximum power point Model-free control Ultra-local model Numerical differentiator

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COVID-19 and Learning Styles: GCET as Case Study

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Computers, Materials & Continua 2021年第7期68卷 103-115页

作者： Mazhar Hussain Malik sid ahmed Amjed Sulaiman Al Hasani Department of Computing and Information Technology Global College of Engineering and TechnologyMuscatSultanate of Oman Department of Electrical and Electronics Engineering Global College of Engineering and TechnologyMuscatSultanate of Oman

The COVID-19 pandemic has caused higher educational institutions around the world to close campus-based activities and move to online *** aim of this paper is to present the case of Global College of Engineering and Technology(GCET)and how its practices including teaching,students/staff support,assessments,and exam policies were *** paper investigates the mediating role of no detriment policy impact on students’result along with the challenges faced by the higher educational institution,recommendations and *** investigation concludes that the strategies adopted for online delivery,student support,assessments and exam policies have helped students to effectively cope with the teaching and learning challenges posed by the COVID-19 pandemic without affecting their academic *** study shows that 99%of students were able to maintain the same or better level of performance during the 1st COVID-19 *** percent of students had shown a slight decrease in their performance(about 1%–2%)with respect to their overall marks *** no detriment policy has succoured those 1%of the students to maintain their overall performance to what it used to be pre-COVID-19 ***,the paper provides the list of challenges and suggestions for smooth conduction of online education.

关键词： Higher education learning styles COVID-19 challenges and strategies no detriment policy engineering and technology modules

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IPv6 Cryptographically Generated Address:Analysis,Optimization and Protection

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Computers, Materials & Continua 2021年第7期68卷 247-265页

作者： Amjed sid ahmed Rosilah Hassan Faizan Qamar Mazhar Malik Department of Computing and Information Technology Global College of Engineering and TechnologyRuwi112Sultanate of Oman Faculty of Information Science and Technology Center for Cyber SecurityUniversiti Kebangsaan MalaysiaBangi43600Malaysia Faculty of Information Science and Technology Universiti Kebangsaan Malaysia43600BangiMalaysia

In networking,one major difficulty that nodes suffer from is the need for their addresses to be generated and verified without relying on a third party or public authorized *** resolve this issue,the use of selfcertifying addresses have become a highly popular and standardized method,of which Cryptographically Generated Addresses(CGA)is a prime *** was primarily designed to deter the theft of IPv6 addresses by binding the generated address to a public key to prove address *** though the CGA technique is highly effective,this method is still subject to several vulnerabilities with respect to security,in addition to certain limitations in its *** this study,the authors present an intensive systematic review of the literature to explore the technical specifications of CGA,its challenges,and existing proposals to enhance the *** that CGA generation is a time-consuming process,this limitation has hampered the application of CGA in mobile environments where nodes have limited energy and *** Hash2 conditions in CGA is the heaviest and most timeconsuming part of *** improve the performance of CGA,we replaced the Secure Hash Algorithm(SHA1)with the Message Digest(MD5)hash ***,this study also analyzes the possible methods through which a CGA could be *** conducting this analysis,Denial-of-Service(DoS)attacks were identified as the main method of attack toward the CGA verification process,which compromise and threaten the privacy of ***,we propose some modifications to the CGA standard verification algorithm to mitigate DoS attacks and to make CGA more security conscious.

关键词： IPv6 GCA SEND DoS attacks RSA SHA-1

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Static and dynamic stability responses of multilayer functionally graded carbon nanotubes reinforced composite nanoplates via quasi 3D nonlocal strain gradient theory

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Defence Technology（防务技术） 2022年第10期18卷 1778-1809页

作者： ahmed Amine Daikh Mohamed sid ahmed Houari Mohamed Ouejdi Belarbi Salwa A.Mohamed Mohamed A.Eltaher Laboratoire D'Etude des Structures et de Mecanique des Materiaux Departement de Genie CivilFacultedes Sciences et de La TechnologieUniversite Mustapha Stambouli B.P.305R.P.29000MascaraAlgeria Laboratoire de Genie Energetique et Materiaux LGEMUniversite de BiskraB.P.145R.P07000BiskraAlgeria Department of Engineering Mathematics Zagazig UniversityP.O.Box 44519ZagazigEgypt Faculty of Engineering Mechanical Engineering DepartmentKing Abdulaziz UniversityP.O.Box 80204JeddahSaudi Arabia Faculty of Engineering Mechanical Design and Production DepartmentZagazig UniversityP.O.Box 44519ZagazigEgypt

This manuscript presents the comprehensive study of thickness stretching effects on the free vibration,static stability and bending of multilayer functionally graded(FG)carbon nanotubes reinforced composite(CNTRC)*** nanoscale and microstructure influences are considered through a modified nonlocal strain gradient continuum *** on power-law functions,four different patterns of CNTs distribution are considered in this analysis,a uniform distribution UD,FG-V CNTRC,FG-X CNTRC,and FG-O CNTRC.A 3D kinematic shear deformation theory is proposed to include the stretching influence,which is neglected in classical ***'s principle is applied to derive the governing equations of motion and associated boundary *** solutions are developed based on Galerkin method to solve the governing equilibrium equations based on the generalized higher-order shear deformation theory and the nonlocal strain gradient theory and get the static bending,buckling loads,and natural frequencies of *** with previous works is presented.A detailed parametric analysis is carried out to highlight the impact of thickness stretching,length scale parameter(nonlocal),material scale parameter(gradient),CNTs distribution pattern,geometry of the plate,various boundary conditions and the total number of layers on the stresses,deformation,critical buckling loads and vibration *** new results are also reported in the current study,which will serve as a benchmark for future research.

关键词： 3D shear deformation theory Free vibration Buckling Bending Galerkin method Functionally graded nanotube Nonlocal strain gradient theory

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Prediction of Thermal Conductivity and Specific Heat of Native Maize Starch and Comparison with HMT Treated Starch

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Journal of Renewable Materials 2019年第6期7卷 535-546页

作者： Aklouche Leila Monteau Jean-Yves Rezzoug sid-ahmed Maugard Thierry Guihard Luc Cohendoz Stephane Maache-Rezzoug Zoulikha LaSIE UMR CNRS 7356University of La RochelleAvenue Michel Crépeau17042 La RochelleFrance GEPEA UMR CNRS 6144ONIRISRue de la Géraudière44322 NantesFrance LIENSs UMR CNRS 7266 Universitéde La RochelleFrance

Specific heat(Cp)and effective thermal conductivity(λ)of native maize starch(NS)were measured by DSC and transient heat transfer method,respectively,at different moisture contents and *** dependency of temperature(T)and moisture content(W)on the two parameters were *** thermophysical properties of treated starch(TS)by four hydrothermal processes(RP-HMT,IV-HMT,DV-HMT and FV-HMT)were measured and compared to native *** treatments were performed at 3 bars(133°C)for 10 *** Cp andλmeasurements,moisture content varied for NS from 5 to 21.5%*** from 8.8 to 25%d.b.,respectively,and was fixed at 6%*** *** models were developed to specific heat and effective thermal conductivity,using a multiple regression algorithm with subsequent statistical *** proposed models for NS based on T and W predict Cp andλwith a mean absolute error of 3.5%and 1.3%,*** differences in specific heat were observed between TS and *** a temperature range of 40 to 160°C,Cp values varied from 1.964 to 2.699 for NS and 1.380 to 2.085(J.g-1.°C-1)for *** contrast,the conductivity of NS was almost identical to that of treated starch by FV-HMT,followed in an increasing order by those treated by DV-HMT,RP-HMT,and IV-HM processes.

关键词： Starch HMT treatment specific heat effective thermal conductivity

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Analyticity of Semigroups Generated by Singular Differential Matrix Operators

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Applied Mathematics 2010年第4期1卷 283-287页

作者： Ould ahmed Mahmoud sid ahmed Adel Saddi 不详

In this paper we prove the analyticity of the semigroups generated by some singular differential matrix operators of the form in the Banach space with suitable boundary conditions. To illustrate the work an example is... 详细信息

关键词： Dissipative Operators Positive Operators Spectrum Analytic Semigroups Evolution Equations

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Value-added Impact of Geostationary Hyperspectral Infrared Sounders on Local Severe Storm Forecasts——via a Quick Regional OSSE

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Advances in Atmospheric Sciences 2018年第10期35卷 1217-1230页

作者： Zhenglong LI Jun LI Pei WANG Agnes LIM Jinlong LI Timothy J.SCHMIT Robert ATLAS sid-ahmed BOUKABARA Ross N.HOFFMAN Cooperative Institute for Meteorological Satellite Studies University of Wisconsin-Madison Center for Satellite Applications and Research NOAA Atlantic Oceanographic and Meteorological Laboratory OAR/NOAA Center for Satellite Applications and Research NOAA

Accurate atmospheric temperature and moisture information with high temporal/spatial resolutions are two of the key parameters needed in regional numerical weather prediction(NWP) models to reliably predict high-impact weather events such as local severe storms(LSSs). High spectral resolution or hyperspectral infrared(HIR) sounders from geostationary orbit(GEO) provide an unprecedented source of near time-continuous, three-dimensional information on the dynamic and thermodynamic atmospheric fields—an important benefit for nowcasting and NWP-based forecasting. In order to demonstrate the value of GEO HIR sounder radiances on LSS forecasts, a quick regional OSSE(Observing System Simulation Experiment)framework has been developed, including high-resolution nature run generation, synthetic observation simulation and validation, and impact study on LSS forecasts. Results show that, on top of the existing LEO(low earth orbit) sounders, a GEO HIR sounder may provide value-added impact [a reduction of 3.56% in normalized root-mean-square difference(RMSD)] on LSS forecasts due to large spatial coverage and high temporal resolution, even though the data are assimilated every 6 h with a thinning of 60 km. Additionally, more frequent assimilations and smaller thinning distances allow more observations to be assimilated, and may further increase the positive impact from a GEO HIR sounder. On the other hand, with denser and more frequent observations assimilated, it becomes more difficult to handle the spatial error correlation in observations and gravity waves due to the limitations of current assimilation and forecast systems(such as a static background error covariance). The peak reduction of 4.6% in normalized RMSD is found when observations are assimilated every 3 h with a thinning distance of 30 km.

关键词： OSSE hyperspectral sounder high-impact weather

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Incidence and Risk Factors of Acute Kidney Injury in ICU Patients of Omdurman Teaching Hospital

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Open Journal of Nephrology 2021年第1期11卷 43-57页

作者： Abdel Mumin sid ahmed Nusaiba Hassan Mohamed Eltahir Omdurman teaching Hospital Omdurman Khartoum State Sudan

Background: Acute kidney injury (AKI) is a common complication in critically ill patients and it is commonly associated with high mortality and morbidity with adverse short and long term outcome. Objectives: The main objective of this study was to determine the incidence of acute kidney injury in ICU patients in Omdurman teaching hospital, and to assess the risk factors associated with the development of acute kidney injury in a critically ill patient. We also intended to find out the impact of acute kidney injury on ICU outcomes. Methods: In this descriptive prospective, cohort hospital-based study, 211 patients were studied and followed up during admission in ICU from November 2019 until July 2020 in Omdurman teaching hospital. Results: 61 patients of the total 211 patients developed renal impairment during their stay in ICU. 64% (39 patients) were males and 36% (22 patients) were female, mean age was 41 ± 5, renal impairment developed after a mean of 5 days of admission and the most common cause was decreased level of consciousness and severe hypotension, sepsis accounting for 40% of the admission. The outcome in ICU showed that the mortality rate was high up to 41% in patients who developed acute kidney injury, Sepsis accounted for over 96% (24 patients) who have passed away. Conclusions: Development of AKI in ICU is an important risk factor for poor outcomes in critically setting. Prevention is the best method for avoiding AKI, with the early identification and recognition of high-risk patients.

关键词： Acute Kidney Injury ICU Risk Factors Outcome Frequency

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