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Mechanical behaviour of fiber-reinforced grout in rock bolt reinforcement

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 437-453页

作者： Yingchun Li ammar Ahmed Danqi Li Deep Underground Engineering Research Center Dalian University of TechnologyDalian116024China WA School of Mines:Minerals Energy and Chemical Engineering Curtin UniversityKalgoorlieWA6430Australia

Grouted rock bolts subject to axial loading in the field exhibit various failure modes,among which the most predominant one is the bolt-grout interface ***,mechanical characterization of the grout is essential for understanding its performance in ground *** date,few studies have been conducted to characterize the mechanical behaviour of fiber-reinforced grout(FRG)in rock bolt *** we experimentally studied the mechanical behaviour of FRG under uniaxial compression,indirect tension,and direct shear loading *** also conducted a series of pullout tests of rebar bolt encapsulated with different grouts including conventional cementitious grout and *** was developed using 15%silica fume(SF)replacement of cement(by weight)and steel fiber to achieve highstrength and crack-resistance to overcome drawbacks of the conventional *** types of steel fibers including straight and wavy steel fibers were further added to enhance the grout *** effect of fiber shape and fiber volume proportion on the grout mechanical properties were *** experimental results showed that the addition of SF and steel fiber by 1.5%fiber volume proportion could lead to the highest compressive,tensile,and shear strengths of the *** minimum volume of fiber that could improve the mechanical properties of grout was found at 0.5%.The scanning electron microscopy(SEM)analysis demonstrated that steel fibers act as an excellent bridge to prevent the cracks from propagating at the interfacial region and hence to aid in maintaining the integrity of the cementitious *** laboratory pullout tests further confirmed that FRG could prevent the cylindrical grout annulus from radial crack and hence improve the rebar’s load carrying ***,FRG has a potential to be utilized in civil and mining applications where high-strength and crack-resistance support is required.

关键词： Fiber-reinforced grout(FRG) Steel fibers Mechanical properties Direct shear test Pullout test

Investigating and predicting the role of photovoltaic, wind, and hydrogen energies in sustainable global energy evolution

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Global Energy Interconnection 2024年第4期7卷 429-445页

作者： Mahmood Swadi Dheyaa Jasim Kadhim Mohamed Salem Firas Mohammed Tuaimah ammar SabriMajeed Ali Jawad Alrubaie Department of Electrical Engineering College of EngineeringUniversity of BaghdadBaghdad 10001Iraq Libyan Authority for Scientific Research Tripoli 80045Libya School of Electrical and Electronic Engineering Universiti Sains Malaysia(USM)Nibong Tebal 14300PenangMalaysia Continuing Education Center University of BaghdadBaghdad 10001Iraq Al-Furat Al-Awsat Technical University AL-Mussaib Technical CollegeBabylonIraq

The global shift toward next-generation energy systems is propelled by the urgent need to combat climate change and the dwindling supply of fossil *** review explores the intricate challenges and opportunities for transitioning to sustainable renewable energy sources such as solar,wind,and *** transition economically challenges traditional energy sectors while fostering new industries,promoting job growth,and sustainable economic *** transition to renewable energy demands social equity,ensuring universal access to affordable energy,and considering community *** environmental benefits include a significant reduction in greenhouse gas emissions and a lesser ecological *** study highlights the rapid growth of the global wind power market,which is projected to increase from$112.23 billion in 2022 to$278.43 billion by 2030,with a compound annual growth rate of 13.67%.In addition,the demand for hydrogen is expected to increase,significantly impacting the market with potential cost reductions and making it a critical renewable energy source owing to its affordability and zero *** 2028,renewables are predicted to account for 42%of global electricity generation,with significant contributions from wind and solar photovoltaic(PV)technology,particularly in China,the European Union,the United States,and *** developments signify a global commitment to diversifying energy sources,reducing emissions,and moving toward cleaner and more sustainable energy *** review offers stakeholders the insights required to smoothly transition to sustainable energy,setting the stage for a resilient future.

关键词： Next energy Renewable energy Sustainability Environmental benefits Economic opportunities

维普期刊数据库

Tribological behavior of shape-specific microplate-enriched synovial fluids on a linear two-axis tribometer

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Friction 2024年第3期12卷 539-553页

作者： Agnese FRAGASSI Antonietta GRECO Martina DI FRANCESCO Luca CESERACCIU Aiman ABU ammar Israel DVIR Thomas Lee MOORE Haytam KASEM Paolo DECUZZI Laboratory of Nanotechnology for Precision Medicine Fondazione Istituto Italiano di TecnologiaGenova 16163Italy Department of Chemistry and Industrial Chemistry University of GenovaGenoa 16146Italy Materials Characterization Facility Istituto Italiano di TecnologiaGenova 16163Italy Department of Pharmaceutical Engineering Azrieli College of Engineering JerusalemJerusalem 9103501Israel Department of Mechanical Engineering Azrieli College of Engineering JerusalemJerusalem 9103501Israel

Nano-and micro-particles are being increasingly used to tune interfacial frictional properties in diverse applications,from friction modifiers in industrial lubrication to enhanced biological fluids in human osteoarthritic ***,we assessed the tribological properties of a simulated synovial fluid enriched with non-spherical,poly lactic-co-glycolic acid(PLGA)microparticles(μPL)that have been previously demonstrated for the pharmacological management of osteoarthritis(OA).Three different μPL configurations were fabricated presenting a 20μm×20μm square base and a thickness of 5μm(thin,5H μPL),10μm(10H μPL),and 20μm(cubical,20H μPL).After extensive morphological and physicochemical characterizations,the apparent Young’s modulus of the μPL was quantified under compressive loading returning an average value of~6 kPa,independently of the particle ***,using a linear two-axis tribometer,the static(μ_(s))and dynamic(μ_(d))friction coefficients of the μPL-enriched simulated synovial fluid were determined in terms of particle configuration and concentration,varying from 0(fluid only)to 6×10^(5) μPL/*** particle morphology had a modest influence on friction,possibly because the μPL were fully squeezed between two mating surfaces by a 5.8 N normal load realizing boundary-like lubrication ***,friction was observed to depend on the dimensionless parameterW,defined as the ratio between the total volume of the μPL enriching the simulated synovial fluid and the volume of the fluid *** coefficients of friction were documented to grow withWreaching a plateau of μ_(s)~0.4 and μ_(d)~0.15,already at Ω~2×10^(-3).Future investigations will have to systematically analyze the effect of sliding velocity,normal load,and rigidity of the mating surfaces to elucidate in full the tribological behavior of μPL in the context of osteoarthritis.

关键词： osteoarthritis microparticles tribology synovial fluid pin on plate

Analysis and Control of the Vehicle Roll Dynamics Using Sum of Squares Polynomial Approach

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Journal of Systems Science & Complexity 2024年

作者： IBEN ammar Imen DOUMIATI Moustapha TALJ Reine CHOKOR Abbas MACHMOUM Mohamed ESEO-IREENA Institut de Recherche en énergie électrique de Nantes Atlantique IREENA UR 4642 37 Boulevard de l’Université-BP406 Sorbonne Universités Université de Technologie de Compiègne CNRS Institut de Recherche en énergie électrique de Nantes Atlantique IREENA UR 4642 37 Boulevard de l’Université-BP 406

The safety of vehicle travel relies on good stability performance, making vehicle motion control a vital technology in vehicles. This paper focuses on investigating the impact of roll control on vehicle performance, particularly in terms of avoiding rollover and ensuring lateral stability. By introducing a feedback roll moment, the roll motion can be effectively controlled. The paper considers two roll reference generators: A static one aimed at zero roll, and a dynamic one based on the vehicle's lateral acceleration. The static roll reference generator enhances stability by employing a fixed reference, particularly beneficial during routine driving conditions. In contrast, the dynamic roll reference generator continually adapts the roll angle reference in response to real-time vehicle dynamics and driving conditions. These proposed reference generators can be paired with varying suspension systems — Static reference could be achieved using semi-active suspensions, while the dynamic one is integrated into advanced active suspension systems, offering heightened adaptability and *** address the roll control objectives, this paper proposes a novel sum of squares(SOS) integral polynomial tracking control. The proposed controller satisfies control bounds and considers control constraints during the design phase. The effectiveness and robustness of the proposed control scheme are evaluated through numerical simulations using a full vehicle nonlinear model in Matlab/Simulink. The results of these simulations are compared to super-twisting sliding mode and Lyapunov-based controllers.

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Parallel Inference for Real-Time Machine Learning Applications

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Journal of Computer and Communications 2024年第1期12卷 139-146页

作者： Sultan Al Bayyat ammar Alomran Mohsen Alshatti Ahmed Almousa Rayyan Almousa Yasir Alguwaifli College of Computer Science and Information Technology Imam Abdulrahman Bin Faisal University Dammam Saudi Arabia

Hyperparameter tuning is a key step in developing high-performing machine learning models, but searching large hyperparameter spaces requires extensive computation using standard sequential methods. This work analyzes the performance gains from parallel versus sequential hyperparameter optimization. Using scikit-learn’s Randomized SearchCV, this project tuned a Random Forest classifier for fake news detection via randomized grid search. Setting n_jobs to -1 enabled full parallelization across CPU cores. Results show the parallel implementation achieved over 5× faster CPU times and 3× faster total run times compared to sequential tuning. However, test accuracy slightly dropped from 99.26% sequentially to 99.15% with parallelism, indicating a trade-off between evaluation efficiency and model performance. Still, the significant computational gains allow more extensive hyperparameter exploration within reasonable timeframes, outweighing the small accuracy decrease. Further analysis could better quantify this trade-off across different models, tuning techniques, tasks, and hardware.

关键词： Machine Learning Models Computational Efficiency Parallel Computing Systems Random Forest Inference Hyperparameter Tuning Python Frameworks (TensorFlow PyTorch Scikit-Learn) High-Performance Computing

Burden of routine orthopedic implant removal a single center retrospective study

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World Journal of Orthopedics 2024年第2期15卷 139-146页

作者： ammar K AlOmran Nader Alosaimi Ahmed A Alshaikhi Omar M Bakhurji Khalid J Alzahrani Basil Ziyad Salloot Tamim Omar Alabduladhem Ahmed I AlMulhim Arwa Alumran Department of Orthopedic College of MedicineImam Abdulrahman Bin Faisal UniversityDammam 31441Saudi Arabia Health Information Management and Technology Department Imam Abdulrahman Bin Faisal UniversityDammam 31441Saudi Arabia

BACKGROUND Open reduction and internal fixation represent prevalent orthopedic procedures,sparking ongoing discourse over whether to retain or remove asymptomatic *** consensus on this matter is paramount for orthopedic *** study aims to quantify the impact of routine implant removal on patients and healthcare facilities.A retrospective analysis of implant removal cases from 2016 to 2022 at King Fahad Hospital of the University(KFHU)was conducted and subjected to statistical *** these cases,44%necessitated hospitalization exceeding one day,while 56%required only a single *** exhibited a 55%need for extended hospital stays,contrasting with 22.8%among the pediatric *** complication rate was 6%,with all patients experiencing at least one ***,34.1%required sick leave and 4.8%exceeded 14 *** anesthesia was predominant(88%).Routine implant removal introduces unwarranted complications,particularly in adults,potentially prolonging *** procedure strains hospital resources,tying up the operating room that could otherwise accommodate critical *** defined institutional guidelines are imperative to regulate this *** To measure the burden of routine implant removal on the patients and *** This is a retrospective analysis study of 167 routine implant removal cases treated at KFHU,a tertiary hospital in Saudi *** were collected in the orthopedic department at KFHU from February 2016 to August 2022,which includes routine asymptomatic implant removal cases across all age *** indications such as infection,pain,implant failure,malunion,nonunion,restricted range of motion,and prominent hardware were *** who had external fixators removed or joints replaced were also *** Between February 2016 and August 2022,360 implants were retrieved;however,only 167 of those who met the inclusion criteria were included in this

关键词： Implant removal Healed fracture Orthopedic implant Complications Healthcare system

Prevalence and associated factors of clubfoot in the eastern province of Saudi Arabia: A hospital-based study

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World Journal of Orthopedics 2024年第7期15卷 635-641页

作者： ammar K Alomran Bandar A Alzahrani Bader S Alanazi Mohammed A Alharbi Loay M Bojubara Eman M Alyaseen Department of Orthopedic College of MedicineImam Abdulrahman bin Faisal UniversityDammam 34212Saudi Arabia College of Medicine Imam Abdulrahman bin Faisal UniversityDammam 34212Saudi Arabia College of Medicine Arabian Gulf UniversityManama 329Bahrain

BACKGROUND Clubfoot,or congenital talipes equinovarus,is a widely recognized cause of disability and congenital deformity worldwide,which significantly impacts the quality of *** management of clubfoot requires long-term,multidiscip-linary *** is important to understand how common this condition is in order to assess its impact on the ***,few studies have investigated the prevalence of clubfoot in Saudi *** To determine the prevalence of clubfoot in Saudi Arabia via the patient population at King Fahad University Hospital(KFUH).METHODS This was a retrospective study conducted at one of the largest hospitals in the country and located in one of the most densely populated of the administrative *** Of the 7792 births between 2015 to 2023 that were included in the analysis,42 patients were diagnosed with clubfoot,resulting in a prevalence of 5.3 per 1000 live births at *** The observed prevalence of clubfoot was significantly higher than both global and local estimates,indicating a substantial burden in the study population.

关键词： Clubfoot Talipes equinovarus Congenital talipes equinovarus Prevalence Saudi Arabia

Improvement of mobility edge model by using new density of states with exponential tail for organic diode

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Chinese Physics B 2015年第4期24卷 360-365页

作者： Muhammad ammar Khan 孙久勋 School of Physical Electronics University of Electronic Science and Technology

The mobility edge （ME） model with single Gaussian density of states （DOS） is simplified based on the recent exper- imental results about the Einstein relationship. The free holes are treated as being non-degenerate, and the trapped holes are dealt with as being degenerate. This enables the integral for the trapped holes to be easily realized in a program. The J-V curves are obtained through solving drift-diffusion equations. When this model is applied to four organic diodes, an obvious deviation between theoretical curves and experimental data is observed. In order to solve this problem, a new DOS with exponential tall is proposed. The results show that the consistence between J-V curves and experimental data based on a new DOS is far better than that based on the Gaussian DOS. The variation of extracted mobility with temperature can be well described by the Arrhenius relationship.

关键词： organic diode potential barriers Einstein relationship

维普期刊数据库

A critical review of intrusion detection systems in the internet of things:techniques,deployment strategy,validation strategy,attacks,public datasets and challenges

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Cybersecurity 2021年第1期4卷 251-277页

作者： Ansam Khraisat ammar Alazab Federation University Australia Federation University AustraliaBallaratAustralia

The Internet of Things(IoT)has been rapidly evolving towards making a greater impact on everyday life to large industrial ***,this has attracted the attention of cybercriminals who made IoT a target of malicious activities,opening the door to a possible attack on the end *** this end,Numerous IoT intrusion detection Systems(IDS)have been proposed in the literature to tackle attacks on the IoT ecosystem,which can be broadly classified based on detection technique,validation strategy,and deployment *** survey paper presents a comprehensive review of contemporary IoT IDS and an overview of techniques,deployment Strategy,validation strategy and datasets that are commonly applied for building *** also review how existing IoT IDS detect intrusive attacks and secure communications on the *** also presents the classification of IoT attacks and discusses future research challenges to counter such IoT attacks to make IoT more *** purposes help IoT security researchers by uniting,contrasting,and compiling scattered research ***,we provide a unique IoT IDS taxonomy,which sheds light on IoT IDS techniques,their advantages and disadvantages,IoT attacks that exploit IoT communication systems,corresponding advanced IDS and detection capabilities to detect IoT attacks.

关键词： Malware Intrusion detection system IoT Anomaly detection Machine learning Deep learning Internet of things Attacks IoT security