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Effect of Graphite Addition on Microstructure, Mechanical Properties and Thermal Properties of Injection Molded AZ91D Alloy+1

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Materials Transactions 2024年第4期65卷 374-380页

作者： Hideshima, Yasutoshi Maeda, Fumiya Fukuta, Tadao Ozaki, Koichi Course of Advanced Systems Engineering Graduate School of Computer Science and Systems Engineering Okayama Prefectural University Soja719-1197 Japan Process Technology Development Department Technology Development Division Seiko Epson Corp. Suwa399-0211 Japan Department of Systems Engineering Faculty of Computer Science and Systems Engineering Okayama Prefectural University Soja719-1197 Japan

Magnesium chips were coated with a high concentration of graphite using a binder and were used as the raw material for injection molding. The microstructure of the magnesium injection-molded product with added graphite exhibited a dispersion of needle-like graphite particles. No significant voids were observed at the interfaces between the graphite and the matrix. The addition of more than 0.5 mass% graphite decreased the proof stress and tensile strength of the injection-molded products. The Young’s modulus of the graphite-added products tended to decrease with an increase in the graphite content, which is consistent with the lower limit of the rule of mixtures. The thermal conductivity of the 6.9 mass% graphite-added product increased compared with that of the AZ91D magnesium alloy and the coefficient of linear thermal expansion decreased. Both values are within a range that satisfied the rules of mixtures. © 2024 The Japan Institute of Metals and Materials.

关键词： Thermal expansion

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Nonlinear dynamic modeling and optimal control of J2 perturbed spacecraft formation flying with periodic coefficients

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Aerospace systems 2024年第2期7卷 327-352页

作者： Ogundele, Ayansola D. Agboola, Olufemi A. Oseni, Olasunkanmi F. Engineering and Space Systems Department National Space Research and Development Agency FCT Abuja Nigeria Oyo State Ogbomoso Nigeria

Nonlinear time-varying system, such as a spacecraft formation flying system with chief spacecraft in elliptical orbit and under the effect of perturbation forces, is difficult to analyze, design, and control based on the presence of time-varying parameters. The proper functioning of aerospace systems and their ability to be able to achieve the designed mission objectives depend largely on proper understanding of their nonlinear time-varying nature, dynamics, and ability to keep them in the required mission operation configurations through high-fidelity optimal control strategy. This paper presents nonlinear dynamics and optimal control of J2 perturbed spacecraft formation flying. Via Euler–Lagrange approach, the nonlinear J2 perturbed motion dynamics was approximated into a time-varying nonlinear form, having periodic coefficients and time-varying parameters, suitable for designing fuel efficient control strategies, spacecraft formation flying, relative motion, and rendezvous mission analysis. Through the application of State-Dependent Riccati Equation (SDRE) approach, the approximated model was converted into a non-unique, pseudo-linear state-dependent coefficient (SDC) form. The numerical simulations confirmed that the SDRE controllers, developed using SDC parameterized systems, are maximally robust and able to return the system to the desired radial, along-track, and cross-track positions. © Shanghai Jiao Tong University 2024.

关键词： Space rendezvous

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Proposed numerical and machine learning models for fiber-reinforced polymer concrete-steel hollow and solid elliptical columns

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Frontiers of Structural and Civil engineering 2024年第8期18卷 1169-1194页

作者： Tang QIONG Ishan JHA Alireza BAHRAMI Haytham F.ISLEEM Rakesh KUMAR Pijush SAMUI School of Applied Technologies Qujing Normal UniversityQujing 655011China Department of Civil Engineering Indian Institute of Technology-BHUVaranasi 221005India Department of Building Engineering Energy Systems and Sustainability ScienceFaculty of Engineering and Sustainable DevelopmentUniversity of GävleGävle 80176Sweden Department of Civil Engineering National Institute of Technology-PatnaPatna 800005India

This study employs a hybrid approach,integrating finite element method(FEM)simulations with machine learning(ML)techniques to investigate the structural performance of double-skin tubular columns(DSTCs)reinforced with glass fiber-reinforced polymer(GFRP).The investigation involves a comprehensive examination of critical parameters,including aspect ratio,concrete strength,number of GFRP confinement layers,and dimensions of steel tubes used in DSTCs,through comparative analyses and parametric *** ensure the credibility of the findings,the results are rigorously validated against experimental data,establishing the precision and trustworthiness of the *** present research work examines the use of the columns with elliptical cross-sections and contributes valuable insights into the application of FEM and ML in the design and evaluation of structural systems within the field of structural engineering.

关键词： elliptical column fiber-reinforced polymer machine learning finite element method ABAQUS

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Auto-tuning PVT data using multi-objective optimization:Application of NSGA-II algorithm

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Petroleum 2024年第1期10卷 135-149页

作者： Abdolhadi Zarifi Mohammad Madani Mohammad Jafarzadegan Reservoir Engineering Systems Petroleum Engineering DepartmentMain Office Building of National Iranian South Oil Company(NISOC)AhvazIran Reservoir Engineering Division Petroleum Engineering DepartmentPetroleum Engineering and Development Company(PEDEC)TehranIran Combined Planning Management National Iranian Oil Company(NIOC)TehranIran

Reservoir simulation is known as perhaps the most widely used,accurate,and reliable method for field development in the petroleum *** integral part of a reliable reservoir simulation process is to consider robust and rigorous tuned EOS ***,EOS models are tuned iteratively through arduous workflows against experimental PVT ***,this comes with a number of drawbacks such as forcingly using weight factors,which upon alteration adversely affects the optimization *** objective of the current work is thus to introduce an auto-tune PVT matching tool using NSGA-II multi-objective *** order to illustrate the robustness of the presented technique,three different PVT samples are used,including two black-oil and one gas condensate *** utilize PengRobinson EOS during all the manual and auto-tuning *** of auto-tuned EOS-generated results with those of experimental and computed statistical error values for these samples clearly show that the proposed method is *** addition,the proposed method,contrary to the manual matching process,provides the engineer with several matched solutions,which allows them to select a match based on the engineering background to be best amenable to the problem at *** addition,the proposed technique is fast,and can output several solutions within less time compared to the traditional manual matching method.

关键词： Auto-tuning PVT Equation of state NSGA-II Multi-objective optimization

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Novel Framework for an Intrusion Detection System Using Multiple Feature Selection Methods Based on Deep Learning

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Tsinghua Science and Technology 2024年第4期29卷 948-958页

作者： A.E.M.Eljialy Mohammed Yousuf Uddin Sultan Ahmad Department of Information Systems College of Computer Engineering and SciencesPrince Sattam Bin Abdulaziz UniversityAlkharjSaudi Arabia Department of Computer Science College of Computer Engineering and SciencesPrince Sattam Bin Abdulaziz UniversityAlkharjSaudi Arabiaand also with University Center for Research and Development(UCRD)Department of Computer Science and EngineeringChandigarh UniversityPunjabIndia

Intrusion detection systems (IDSs) are deployed to detect anomalies in real time. They classify a network’s incoming traffic as benign or anomalous (attack). An efficient and robust IDS in software-defined networks is an inevitable component of network security. The main challenges of such an IDS are achieving zero or extremely low false positive rates and high detection rates. Internet of Things (IoT) networks run by using devices with minimal resources. This situation makes deploying traditional IDSs in IoT networks unfeasible. Machine learning (ML) techniques are extensively applied to build robust IDSs. Many researchers have utilized different ML methods and techniques to address the above challenges. The development of an efficient IDS starts with a good feature selection process to avoid overfitting the ML model. This work proposes a multiple feature selection process followed by classification. In this study, the Software-defined networking (SDN) dataset is used to train and test the proposed model. This model applies multiple feature selection techniques to select high-scoring features from a set of features. Highly relevant features for anomaly detection are selected on the basis of their scores to generate the candidate dataset. Multiple classification algorithms are applied to the candidate dataset to build models. The proposed model exhibits considerable improvement in the detection of attacks with high accuracy and low false positive rates, even with a few features selected.

关键词： random forest feature selection decision tree software-defined network logistic regression intrusion detection system XGB classifier AdaBoost

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Optimization of cyclone separator for oil palm loose fruit collection using computational fluid dynamics and response surface methodology

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engineering in Agriculture, Environment and Food 2024年第3期17卷 82-90页

作者： Lim, Adam Danial Lim bin Jefri Abu Bakar, Saiful Anuar Ahmad Zaharuddin, Mohd Faridh Muhamad Said, Mohd Farid Department of Aeronautics Automotive and Ocean Engineering Faculty of Mechanical Engineering Universiti Teknologi Malaysia Malaysia Department of Manufacturing and Industrial Engineering Faculty of Mechanical Engineering Universiti Teknologi Malaysia Malaysia Automotive Development Centre Institute of Vehicle Systems and Engineering Universiti Teknologi Malaysia Malaysia Department of Agricultural and Biosystems Engineering Faculty of Engineering Universiti Putra Malaysia Malaysia

Computational fluid dynamics (CFD) and response surface methodology were used to optimize a two-stage cyclone separator with critical diameters of 0.3 m and 0.4 m for oil palm loose fruit collection. Interactions between inlet air speed, vortex finder length, and exit diameter on the pressure drop, collection efficiency, and separation efficiency were investigated using response surface methodology. Results indicate that all factors were significant with a p-value −1, a vortex finder length of 0.405 m, and an exit diameter of 0.131 m. © 2024 Asian Agricultural and Biological engineering Association. All rights reserved.

关键词： Vortex flow

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Practical Considerations and Limitations of Using Leaf and Canopy Temperature Measurements as a Stomatal Conductance Proxy:Sensitivity across Environmental Conditions,Scale,and Sample Size

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Plant Phenomics 2024年第2期6卷 416-432页

作者： Ismael K.Mayanja Christine H.Diepenbrock Vincent Vadez Tong Lei Brian N.Bailey Department of Biological Systems Engineering University of CaliforniaDavisDavisCAUSA Department of Plant Sciences University of CaliforniaDavisDavisCAUSA French National Research Institute for Sustainable Development(IRD) UMR DIADEUniversity of MontpellierMontpellierFrance

Stomatal conductance(gs)is a crucial component of plant physiology,as it links plant productivity and water loss through *** gs indirectly through leaf temperature(Tl)measurement is common for reducing the high labor cost associated with direct gs ***,the relationship between observed Tl and gs can be notably affected by local environmental conditions,canopy structure,measurement scale,sample size,and gs itself.

关键词： environmental temperature conditions canopy sample proxy scale leaf across conductance

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Voltage and power control for distributed generation units in islanded microgrids 6th

Voltage and power control for distributed generation units i...

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6th International Conference on Renewable Energies Offshore, RENEW 2024

作者： Rouch, T. Bagheri M’zoughi, F. Aboutalebi, P. Ahmad, I. Garrido, A.J. Garrido, I. Institute of Research and Development of Processes—IIDP Department of Automatic Control and Systems Engineering Faculty of Engineering of Bilbao University of the Basque Country Bilbao Spain

ISBN: (纸本)9781032905570

This article presents an optimized control strategy tailored for DC islanded microgrids, featuring a voltage controller based on mixed H2/H∞ state feedback using linear matrix inequalities (LMIs) and a power controller guided by droop characteristics. A polytopic modeling approach addresses system uncertainties and nonlinearities. The controller aims to stabilize the system, reject disturbances, equitably distribute power among distributed generation units (DGUs), and minimize energy consumption. Regional pole placement ensures welldamped transient responses. Simulation results demonstrate effective management of load perturbations and DGU disconnections, with a comparative analysis against an H∞ controller offering additional insights into performance. © 2025 The Author(s).

关键词： Microgrids

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Fabrication of SiC particle dispersed AZ91D magnesium alloy composite by injection molding method and their properties

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Keikinzoku/Journal of Japan Institute of Light Metals 2024年第3期74卷 141-146页

作者： Hideshima, Yasutoshi Maeda, Fumiya Fukuta, Tadao Ozaki, Koichi Graduate School of Computer Science and Systems Engineering Okayama Prefectural University 111 Kuboki Okayama Soja-shi719-1197 Japan Process Technology Development Department Technology Development Division Seiko Epson Co. Suwa-shi Nagano Japan Faculty of Computer Science and Systems Engineering Okayama Prefectural University Okayama Soja-shi Japan

AZ91D magnesium alloy chips were coated with SiC powder using a binder, and injection molding was attempted using SiC powder coated magnesium chips as raw material. The metallurgical structure of the injection molded products showed uniform dispersion of SiC particles in the matrix, and there were no significant defects such as voids at the SiC particle-matrix interface. The hardness and 0.2% proof stress of the injection molded products tended to improve with increasing SiC content, while the elongation decreased with increasing SiC content. The Young's modulus of the injection molded products improved with increasing SiC content. It was confirmed that the specific bending rigidity of the injection molded products also improves due to the significant increase in the Young's modulus, although the addition of SiC leads to an increase in density. © 2024 The Japan Institute of Light Metals.

关键词： Silicon carbide

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Advanced DC-DC converter topologies for solar energy harvesting applications:a review

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Clean Energy 2023年第3期7卷 555-570页

作者： Tole Sutikno Ahmad Saudi Samosir Rizky Ajie Aprilianto Hendril Satrian Purnama Watra Arsadiando Sanjeevikumar Padmanaban Department of Electrical Engineering Universitas Ahmad DahlanYogyakartaIndonesia Department of Electrical Engineering Universitas LampungBandar LampungIndonesia Embedded Systems and Power Electronics Research Group YogyakartaIndonesia Department of Business Development and Technology Aarhus UniversityHerningDenmark

In this study,the advanced topologies of a DC-DC converter for applications involving the harvesting of solar energy are *** work’s primary contribution is a guide for choosing the most effective topology for a DC-DC converter when developing solar energy collection *** topologies of a DC-DC converter for solar energy harvesting applications are compared in terms of the range of power levels they can oversee,the complexity of the underlying hardware,the cost of implementation,the tracking efficiency and the overall efficiency of the *** article explains five innovative approaches for adapting boost converters to function as standard DC-DC converters to capture solar energy,consisting of(i)voltage-multiplier cell,(2)coupled inductor,(3)coupled inductor and switch capacitor,(4)cascaded topology and(5)voltage-lift *** of the boost converter’s restrictions,it is necessary to deliver high *** comparison findings demonstrate that the voltage-lift-based boost-converter topology performs more effectively than the *** conclusion,the information presented in this paper can be utilized when developing solar energy collection systems to determine the sort of direct current to direct current converter that will be most effective.

关键词： boost converter DC-DC converter energy harvesting renewable energy solar photovoltaic

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