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Numerical study of the near-wall vortical structures in particle-laden turbulent flow by a new vortex identification method-Liutex

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Journal of Hydrodynamics 2024年第1期36卷 53-60页

作者： Farid Rousta Goodarz ahmadi Bamdad Lessani Chaoqun Liu Department of Mechanical and Aerospace Engineering Clarkson UniversityPotsdamNYUSA Mechanical Engineering and Engineering Science The University of North Carolina at CharlotteNCUSA Department of Mathematics University of Texas at ArlingtonArlingtonTXUSA

This study investigates turbulent particle-laden channel flows using direct numerical simulations employing the Eulerian-Lagrangian method.A two-way coupling approach is adopted to explore the mutual interaction between particles and fluid *** considered cases include flow with particle Stokes number varying from St=2 up to St=100 while maintaining a constant Reynolds number of Reτ=180 across all cases.A novel vortex identification method,Liutex(Rortex),is employed to assess its efficacy in capturing near-wall turbulent coherent structures and their interactions with *** Liutex method provides valuable information on vortex strength and vectors at each location,enabling a detailed examination of the complex interaction between fluid and particulate *** widely acknowledged,the interplay between clockwise and counterclockwise vortices in the near-wall region gives rise to low-speed streaks along the *** low-speed streaks serve as preferential zones for particle concentration,depending upon the particle Stokes *** is shown that the Liutex method can capture these vortices and identify the location of low-speed ***,it is observed that the particle Stokes number(size)significantly affects both the strength of these vortices and the streaky structure exhibited by ***,a quantitative analysis of particle behavior in the near-wall region and the formation of elongated particle lines was carried *** involved examining the average fluid streamwise velocity fluctuations at particle locations,average particle concentration,and the normal velocity of particles for each set of particle Stokes *** investigation reveals the intricate interplay between particles and near-wall structures and the significant influence of particles Stokes *** study contributes to a deeper understanding of turbulent particle-laden channel flow dynamics.

关键词： Turbulent channel flow particle-laden flow direct numerical simulation(DNS) Eulerian-Lagrangian vortex identification turbulence coherent structures Liutex

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RoGRUT: A Hybrid Deep Learning Model for Detecting Power Trapping in Smart Grids

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Computers, Materials & Continua 2024年第5期79卷 3175-3192页

作者： Farah Mohammad Saad Al-ahmadi Jalal Al-Muhtadi Center of Excellence in Information Assurance(CoEIA) King Saud UniversityRiyadh11543Saudi Arabia College of Computer&Information Sciences King Saud UniversityRiyadh11543Saudi Arabia

electricity theft is a widespread non-technical issue that has a negative impact on both power grids and electricity *** hinders the economic growth of utility companies,poses electrical risks,and impacts the high energy costs borne by *** development of smart grids is crucial for the identification of power theft since these systems create enormous amounts of data,including information on client consumption,which may be used to identify electricity theft using machine learning and deep learning ***,there also exist different solutions such as hardware-based solutions to detect electricity theft that may require human resources and expensive ***-based solutions are presented in the literature to identify electricity theft but due to the dimensionality curse,class imbalance issue and improper hyper-parameter tuning of such models lead to poor *** this research,a hybrid deep learning model abbreviated as RoGRUT is proposed to detect electricity theft as amalicious and non-malicious *** key steps of the RoGRUT are data preprocessing that covers the problem of class imbalance,feature extraction and final theft *** advanced-level models like RoBERTa is used to address the curse of dimensionality issue,the near miss for class imbalance,and transfer learning for *** effectiveness of the RoGRUTis evaluated using the dataset fromactual smartmeters.A significant number of simulations demonstrate that,when compared to its competitors,the RoGRUT achieves the best classification *** performance evaluation of the proposed model revealed exemplary results across *** accuracy achieved was 88%,with precision at an impressive 86%and recall reaching 84%.The F1-Score,a measure of overall performance,stood at 85%.Furthermore,themodel exhibited a noteworthyMatthew correlation coefficient of 78%and excelled with an area under the curve of 91%.

关键词： electricity theft smart grid RoBERTa GRU transfer learning

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GAN‐MD:A myocarditis detection using multi‐channel convolutional neural networks and generative adversarial network‐based data augmentation

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CAAI Transactions on Intelligence Technology 2024年第4期9卷 866-878页

作者： Hengame ahmadi Golilarz Alireza Azadbar Roohallah Alizadehsani Juan Manuel Gorriz Department of Medical Radiation Engineering Faculty of EngineeringLahijan BranchIslamic Azad UniversityLahijanIran Department of Medical Radiation Engineering Lahijan BranchIslamic Azad UniversityLahijanIran Institute for Intelligent Systems Research and Innovation(IISRI) Deakin UniversityWaurn PondsVictoriaAustralia Data Science and Computational Intelligence Institute University of GranadaGranadaSpain

Myocarditis is a significant public health concern because of its potential to cause heart failure and sudden *** standard invasive diagnostic method,endomyocardial bi-opsy,is typically reserved for cases with severe complications,limiting its widespread ***,non‐invasive cardiac magnetic resonance(CMR)imaging presents a promising alternative for detecting and monitoring myocarditis,because of its high signal contrast that reveals myocardial *** assist medical professionals via artificial intelligence,the authors introduce generative adversarial networks‐multi discriminator(GAN‐MD),a deep learning model that uses binary classification to diagnose myocarditis from CMR *** approach employs a series of convolutional neural networks(CNNs)that extract and combine feature vectors for accurate *** authors suggest a novel technique for improving the classification precision of *** generative adversarial networks(GANs)to create synthetic images for data augmentation,the authors address challenges such as mode collapse and unstable *** a reconstruction loss into the GAN loss function requires the generator to produce images reflecting the discriminator features,thus enhancing the generated images'quality to more accurately replicate authentic data ***,combining this loss function with other reg-ularisation methods,such as gradient penalty,has proven to further improve the perfor-mance of diverse GAN models.A significant challenge in myocarditis diagnosis is the imbalance of classification,where one class dominates over the *** mitigate this,the authors introduce a focal loss‐based training method that effectively trains the model on the minority class *** GAN‐MD approach,evaluated on the Z‐Alizadeh Sani myocarditis dataset,achieves superior results(F‐measure 86.2%;geometric mean 91.0%)compared with other deep learning models and traditional machine learning methods.

关键词： 2‐D 3‐D

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Recent advances in heterogeneous catalysis of solar-driven carbon dioxide conversion

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Journal of Environmental Sciences 2024年第6期140卷 165-182页

作者： Jun Xu Farzaneh Arabpour Roghabadi Ying Luo Vahid ahmadi Qian Wang Zheng Wang Hong He State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Chemistry and Chemical Engineering Henan Polytechnic UniversityJiaozuoHenan 454000China Department of Process Engineering Faculty of Chemical EngineeringTarbiat Modares UniversityTehranIran Optoelectronics and Nanophotonics Research Group Faculty of Electrical and Computer EngineeringTarbiat Modares UniversityTehranIran Graduate School of Engineering Nagoya UniversityFuro-choChikusa-kuNagoya 464-8603Japan

Solar-driven carbon dioxide(CO_(2))conversion including photocatalytic(PC),photoelectrochemical(PEC),photovoltaic plus electrochemical(PV/EC)systems,offers a renewable and scalable way to produce fuels and high-value chemicals for environment and energy *** review summarizes the basic fundament and the recent advances in the field of solar-driven CO_(2)*** the visible-light absorption is an important strategy to improve solar energy conversion *** separation and migration of photogenerated charges carriers to surface sites and the surface catalytic processes also determine the photocatalytic *** engineering including co-catalyst loading,defect engineering,morphology control,surface modification,surface phase junction,and Z-scheme photocatalytic system construction,have become fundamental strategies to obtain high-efficiency *** to photocatalysis,these strategies have been applied to improve the conversion efficiency and Faradaic efficiency of typical PEC *** PV/EC systems,the electrode surface structure and morphology,electrolyte effects,and mass transport conditions affect the activity and selectivity of electrochemical CO_(2)***,the challenges and prospects are addressed for the development of solar-driven CO_(2)conversion system with high energy conversion efficiency,high product selectivity and stability.

关键词： Solar-driven CO_(2)reduction Photocatalytic system Photoelectrochemical system Photovoltaic plus electrochemical system Surface/interface engineering

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Studying the effect of surfactant assisted low-salinity water flooding on clay-rich sandstones

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Petroleum 2024年第2期10卷 306-318页

作者： Saeed Khezerloo-ye Aghdam Alireza Kazemi Mohammad ahmadi Department of Petroleum Engineering Amirkabir University of Technology (AUT) Department of Petroleum and Chemical Engineering College of Engineering Sultan Qaboos University

Sandstone reservoirs often contain clay particles that can cause damage and reduce permeability during low-salinity water flooding. In this study, the effect of surfactants on fine migration in clay-rich sandstones and its impact on oil recovery was ***, the impact of surfactants on interparticle forces in fine-matrix, fine-fine, and oil-matrix systems was modeled. The results showed that both CTAB(cetyltrimethyl ammonium bromide) and QS(quillaja saponin) cause EDL compaction, weakening the repulsive forces. However, SDS(sodium dodecyl sulfate)and TX(triton X-100) do not affect the EDL. Next, the effect of surfactants on IFT reduction and wettability alteration was experimentally investigated. All surfactants reduced IFT due to the surface excessive concentration mechanism. The wettability alteration experiment illustrated that although QS and CTAB compact EDL around oil and matrix particles leading to attraction force augmentation, they both alter wettability through adsorption on matrix and carboxylic groups present in crude oil, *** aqueous solutions were then injected into various clay-rich sandstone sanpacks, which resulted in increased oil recovery. However, the mechanisms leading to enhanced oil recovery variedby surfactant type. CTAB increased recovery by 10% through IFT reduction and wettability alteration, while SDS and TX increased recovery by 12% and 9%, respectively, through wettability alteration and extreme fine migration. In contrast, partial fine migration in the QS flooding experiment reached a recovery increase of 18%. Permeability trends through experiments were also recorded. During CTAB injection,permeability did not reduce, while QS aqueous solution reduced rock permeability to 5 m D. SDS and TX reduced the magnitude of permeability to 2 m *** conclusion, this study demonstrates that surfactants can effectively improve oil recovery in clay-rich sandstones by altering the interparticle forces, reducing IFT, a

关键词： Surfactant flooding Smart water Fine migration Recovery factor

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Advances in oral mesenchymal stem cell-derived extracellular vesicles in health and disease

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Genes & Diseases 2024年第1期11卷 346-357页

作者： Huanyu Luo Anahid ahmadi Birjandi Feilong Ren Tianmeng Sun Paul T.Sharpe Hongchen Sun Zhengwen An Department of Oral Biology Jilin Provincial Key Laboratory of Tooth Development and Bone RemodelingSchool and Hospital of StomatologyJilin UniversityChangchunJilin 130021China Faculty of Dentistry Oral&Craniofacial SciencesCentre for Craniofacial and Regenerative BiologyKing's College LondonLondonSE19RTUK Department of Oral Pathology Jilin Provincial Key Laboratory of Tooth Development and Bone RemodelingSchool and Hospital of StomatologyJilin UniversityChangchunJilin 130021China

Extracellular vesicles(EVs)are nano-size vesicles secreted naturally by all cells into the extracellular space and have been recognized as important cell-cell mediators in multicel-lular *** contain nucleic acids,proteins,lipids,and other cellular components,regulating many basic biological processes and playing an important role in regenerative med-icine and *** can be traced to their cells of origin and exhibit a similar ***,EVs demonstrate low immunogenicity,good biocompatibility,and fewer side ef-fects,compared to their parent *** stem cells(MsCs)are one of the most important resource cells for EVs,with a great capacity for self-renewal and multipotent differ-entiation,and play an essential role in stem cell *** mechanism of MsC therapy was thought to be attributed to the differentiation of MsCs after targeted migration,as previously ***,emerging evidence shows the previously unknown role of MsC-derived para-crine factors in stem cell *** EVs derived from oral tissue MSCs(OMSC-EVs),show more advantages than those of all other MsCs in tissue repair and regeneration,due to their lower invasiveness and easier accessibility for sample ***,we systematically review the biogenesis and biological characteristics of OMSC-EVs,as well as the role of OMsC-EVs in intercellular ***,we discuss the potential therapeutic roles of OMSC-EVs in oral and systemic *** highlight the current challenges and future directions of OMSC-EVs to focus more attention on clinical *** aim to provide valuable insights for the explorative clinical application of OMSC-EVs.

关键词： Disease Extracellular vesicles Oral tissue MSC Therapeutic application Tissue regeneration

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Security Implications of Edge Computing in Cloud Networks

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Journal of Computer and Communications 2024年第2期12卷 26-46页

作者： Sina ahmadi National Coalition of Independent Scholars (NCIS) Seattle USA

Security issues in cloud networks and edge computing have become very common. This research focuses on analyzing such issues and developing the best solutions. A detailed literature review has been conducted in this regard. The findings have shown that many challenges are linked to edge computing, such as privacy concerns, security breaches, high costs, low efficiency, etc. Therefore, there is a need to implement proper security measures to overcome these issues. Using emerging trends, like machine learning, encryption, artificial intelligence, real-time monitoring, etc., can help mitigate security issues. They can also develop a secure and safe future in cloud computing. It was concluded that the security implications of edge computing can easily be covered with the help of new technologies and techniques.

关键词： Edge Computing Cloud Networks Artificial Intelligence Machine Learning Cloud Security

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Systematic Literature Review on Cloud Computing Security: Threats and Mitigation Strategies

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Journal of Information Security 2024年第2期15卷 148-167页

作者： Sina ahmadi National Coalition of Independent Scholars Seattle United States

Cloud computing plays a significant role in modern information technology, providing organizations with numerous benefits, including flexibility, scalability, and cost-efficiency. However, it has become essential for organizations to ensure the security of their applications, data, and cloud-based networks to use cloud services effectively. This systematic literature review aims to determine the latest information regarding cloud computing security, with a specific emphasis on threats and mitigation strategies. Additionally, it highlights some common threats related to cloud computing security, such as distributed denial-of-service (DDoS) attacks, account hijacking, malware attacks, and data breaches. This research also explores some mitigation strategies, including security awareness training, vulnerability management, security information and event management (SIEM), identity and access management (Iam), and encryption techniques. It discusses emerging trends in cloud security, such as integrating artificial intelligence (AI) and machine learning (ML), serverless computing, and containerization, as well as the effectiveness of the shared responsibility model and its related challenges. The importance of user awareness and the impact of emerging technologies on cloud security have also been discussed in detail to mitigate security risks. A literature review of previous research and scholarly articles has also been conducted to provide insights regarding cloud computing security. It shows the need for continuous research and innovation to address emerging threats and maintain a security-conscious culture in the company.

关键词： Cloud Security Threat Analysis Mitigation Strategies Emerging Trends Ethi-cal Considerations Data Analysis

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Surveying organic matter， thermal maturity level， and paleo-environmental conditions by considering biomarker and stable carbon isotopic analysis

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Journal of Earth Science 2024年

作者： Meysam Hemmati Yaser ahmadi Behzad Vaferi Ali Hosin Alibak David A.Wood DWA Energy Limited School of Geology College of Science University of Tehran Petroleum Engineering Department Faculty of Engineering Soran University Department of Chemical Engineering Shiraz Branch Islamic Azad University Chemical and Petroleum Engineering Department Ilam University

Biomarker and stable carbon isotope analyses are presented for the Garau formation of the Cretaceous age， an important source rock in western Iran， to reveal its potential as an oil-prone source rock. The C28/C29sterane ratio value range (0.72 to 0.83) of bitumen samples from the formation suggests that they were likely formed during phytoplankton blooms. Sterane， hopane， and isoprenoid/n-alkane ratios indicate that the formation’s organic matter predominantly consists of algae， and bacteria， accompanied by some reworked material derived from higher plants. Due to the predominance of anoxic conditions and the actions of sulfate-reducing bacteria， the bitumen present is enriched with sulfur compounds. The percentages of saturates， aromatics， and nitrogen-sulfur-oxygen (NSO) fractions in the bitumen samples classify them as naphthenic oils. Isotope analysis reveals that biodegradation and water-washing have reduced the concentrations of some volatile saturates and low molecular weight aromatics in the bitumen samples. These actions have resulted in distinctive δ13C values for the formation’s kerogen and bitumen fractions. The formation’s organic matter has been subjected to high-temperature thermal regimes and has entered the oil-generation window at the sampled localities， with vitrinite reflectance (%RC) varying between 0.7% and 0.75%.

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Robotic-assisted retroperitoneal lymph node dissection for stage II testicular cancer

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Asian Journal of Urology 2024年第1期11卷 121-127页

作者： George McClintock Ahmed S.Goolam Don Perera Ryan Downey Scott Leslie Peter Grimison Henry Woo Peter Ferguson Nariman ahmadi Department of Urology Chris O'Brien LifehouseSydneyNSWAustralia Department of Anaesthesia Chris O'Brien LifehouseSydneyNSWAustralia The University of Sydney SydneyNSW2006Australia Department of Medical Oncology Chris O'Brien LifehouseSydneyNSWAustralia

Objective:To evaluate the perioperative as well as early oncological outcomes of patients undergoing robotic retroperitoneal lymph node dissection for treatment of testicular ***:We conducted a prospective consecutive case series of patients undergoing robotic assisted retroperitoneal lymph node dissection for metastatic testicular cancer between May 2018 and July 2021 at our *** were collected on patient and tumour characteristics,intraoperative and postoperative parameters,and functional and oncological *** statistics are ***:Nineteen patients were identified;18(94.7%)completed the procedure robotically and one was converted to open surgery;78.9%of patients had stage≥IIB and 12(63.2%)patients had undergone prior *** median operative time was 300(interquartile range[IQR]240-315)*** blood loss was 100(IQR 50-175)*** length of stay was 2(range 1-11)*** robotically completed patients commenced diet and passed flatus on Day 1 and were discharged by Day *** median lymph node yield was 40.5(IQR 38-51)*** patients undergoing nerve-sparing procedures recovered antegrade ejaculatory *** patient had a Clavien-Dindo III complication(chylous ascites requiring drainage).At a median follow-up of 22.3(IQR 16.3-24.9)months,one patient developed retroperitoneal recurrence,which was successfully treated with second-line chemotherapy;no other patients have had ***:Robotic retroperitoneal lymph node dissection is a safe and feasible alternative to open surgery in appropriately selected patients,offering low *** oncological outcomes are *** cohorts and longer follow-ups are required to validate our institution's findings.

关键词： Retroperitoneal lymph node dissection Robotic surgery Testicular cancer Retroperitoneal node dissection

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