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Investigation of system parameters towards safer impact based shock-to-detonation transition in a novel laser driven flyer plate prototype

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DEFENCE TECHNOLOGY 2024年第9期39卷 103-113页

作者： Ozkasapoglu, Gonca Saglam Onel, Selis Hacettepe univ Inst Sci TR-06800 Beytepe Turkiye TUBITAK SAGE Def Ind Res & Dev Inst TR-06261 Ankara Turkiye Hacettepe univ Dept Chem Engn TR-06800 Ankara Turkiye

Laser driven flyer plate technology offers improved safety and reliability for detonation of explosives in industrial applications ranging from mining and stone quarrying to the aerospace and defense industries. This study is based on developing a safer laser driven flyer plate prototype comprised of a laser initiator and a flyer plate subsystem that can be used with secondary explosives. System parameters were optimized to initiate the shock-to-detonation transition (SDT) of a secondary explosive based on the impact created by the flyer plate on the explosive surface. Rupture of the flyer was investigated at the mechanically weakened region located on the interface of these subsystems, where the product gases from the deflagration of the explosive provide the required energy. A bilayer energetic material was used, where the first layer consisted of a pyrotechnic component, zirconium potassium perchlorate (ZPP), for sustaining the ignition by the laser beam and the second layer consisted of an insensitive explosive, cyclotetramethylene-tetranitramine (HMX), for deflagration. A plexiglass interface was used to enfold the energetic material. The focal length of the laser beam from the diode was optimized to provide a homogeneous beam profile with maximum power at the surface of the ZPP. Closed bomb experiments were conducted in an internal volume of 10 cm(3) for evaluation of performance. Dependency of the laser driven flyer plate system output on confinement, explosive density, and laser beam power were analyzed. Measurements using a high-speed camera resulted in a flyer velocity of 670 +/- 20 m/s that renders the prototype suitable as a laser detonator in applications, where controlled employment of explosives is critical. (c) 2024 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： Laser driven flyer plate Shock to detonation transition Detonation Secondary explosives Pyrotechnic materials Confinement IGNITION INITIATION ENERGY

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Towards a lightweight security framework using blockchain and machine learning

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BLOCKCHAIN-RESEARCH AND APPLICATIONS 2024年第1期5卷 107-118页

作者： Ismail, Shereen Nouman, Muhammad Dawoud, Diana W. Reza, Hassan univ North Dakota Sch Elect Engn & Comp Sci Grand Forks ND 58202 USA COMSATS univ Islamabad Dept Comp Sci Islamabad 44000 Pakistan univ Dubai Coll Engn & Informat Technol Dubai U Arab Emirates

Cyber-attacks pose a significant challenge to the security of Internet of Things (IoT) sensor networks, necessitating the development of robust countermeasures tailored to their unique characteristics and limitations. Various prevention and detection techniques have been proposed to mitigate these attacks. In this paper, we propose an integrated security framework using blockchain and Machine Learning (ML) to protect IoT sensor networks. The framework consists of two modules: a blockchain prevention module and an ML detection module. The blockchain prevention module has two lightweight mechanisms: identity management and trust management. Identity management employs a lightweight Smart Contract (SC) to manage node registration and authentication, ensuring that unauthorized entities are prohibited from engaging in any tasks, while trust management uses a lightweight SC that is responsible for maintaining trust and credibility between sensor nodes throughout the network's lifetime and tracking historical node behaviors. Consensus and transaction validation are achieved through a Verifiable Byzantine Fault Tolerance (VBFT) mechanism to ensure network reliability and integrity. The ML detection module utilizes the Light Gradient Boosting Machine (LightGBM) algorithm to classify malicious nodes and notify the blockchain network if it must make decisions to mitigate their impacts. We investigate the performance of several off -the -shelf ML algorithms, including Logistic Regression, Complement Naive Bayes, Nearest Centroid, and Stacking, using the WSN-DS dataset. LightGBM is selected following a detailed comparative analysis conducted using accuracy, precision, recall, F1 -score, processing time, training time, prediction time, computational complexity, and Matthews Correlation Coefficient (MCC) evaluation metrics.

关键词： Blockchain Machine learning IoT Security Integration Smart contracts

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Promoting rigor in blockchain energy and environmental footprint research: A systematic literature review

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BLOCKCHAIN-RESEARCH AND APPLICATIONS 2024年第1期5卷 133-151页

作者： Sai, Ashish Rajendra Vranken, Harald Open univ Dept Comp Sci NL-6419 AT Heerlen Netherlands Maastricht univ Dept Adv Comp Sci NL-6211 LK Maastricht Netherlands Radboud univ Nijmegen Inst Comp & Informat Sci NL-6525 XZ Nijmegen Netherlands

There is a growing interest in understanding the energy and environmental footprint of digital currencies, specifically in cryptocurrencies such as Bitcoin and Ethereum. These cryptocurrencies are operated by a geographically distributed network of computing nodes, making it hard to estimate their energy consumption accurately. Existing studies, both in academia and industry, attempt to model cryptocurrency energy consumption often based on a number of assumptions, for instance, about the hardware in use or the geographic distribution of the computing nodes. A number of these studies have already been widely criticized for their design choices and subsequent over- or under-estimation of energy use. In this study, we evaluate the reliability of prior models and estimates by leveraging existing scientific literature from fields cognizant of blockchain, such as social energy sciences and information systems. We first design a quality assessment framework based on existing research, and we then conduct a systematic literature review examining scientific and non-academic literature demonstrating common issues and potential avenues of addressing these issues. Our goal with this article is to advance the field by promoting scientific rigor in studies focusing on blockchain energy footprint. To that end, we provide a novel set of codes of conduct for the five most widely used research methodologies: Quantitative energy modeling, literature reviews, data analysis and statistics, case studies, and experiments. We envision that this code of conduct would assist in standardizing the design and assessment of studies focusing on blockchain-based systems' energy and environmental footprint.

关键词： Blockchain Energy consumption Environmental footprint Scientific rigor Reliability CARBON FOOTPRINT BITCOIN CONSUMPTION KAPPA

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A novel control strategy of a variable-speed doubly-fed-induction-generator-based wind energy conversion system

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CLEAN ENERGY 2024年第1期8卷 153-170页

作者： Mohapatra, Shibani Prasad Dash, Pradipta Kishore Siksha O Anusandhan Deemed univ Dept Elect Engn Bhubaneswar 751030 Odisha India Siksha O Anusandhan Deemed univ Multidisciplinary Res Cell Bhubaneswar 751030 Odisha India

This paper aims to address the issue of control of a variable-speed wind turbine based on doubly-fed induction generators. In this work, an effort is made to extract the maximum efficiency from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. In the first step, a maximum power point tracking technique is used to extract the maximum power from the turbine. Then a stator-flux-oriented vector control strategy is employed to control the rotor-side current. Subsequently, a grid voltage vector-oriented control strategy is used to control the grid-side system of the grid-connected generator. Considering the nonlinearity and parameter uncertainty of the system, an active disturbance rejection controller with a sliding-mode-based extended-state observer is developed for the above-mentioned control strategies. Furthermore, the stability of the controller is tested and the performance of the controller is compared with the classical proportional-integral controller based on disturbance rejection, robustness and tracking capability in a highly non-linear wind speed variation scenario. Modelling, control and comparison are conducted in the MATLAB (R)/Simulink (R) environment. Finally, a real-time hardware set-up is presented using the dSPACE ds-1104 R&D processing board to validate the control scheme. From the result of the experiments, it is seen that the proposed controller takes 10-15 control cycles to settle to its steady-state values, depending on the control loop, whereas the conventional proportional-integral controller takes 60-75 control cycles. As a result, the settling time for the proposed control scheme is shorter than that of the proportional-integral controller. The maximum efficiency is extracted from a doubly-fed induction generator-based variable-speed wind turbine by controlling the rotor current. A maximum power point tracking technique is used in combination with a stator-flux-oriented vector control strate

关键词： doubly-fed induction generator variable-speed wind turbine vector control active disturbance rejection controller stability analysis NONLINEAR CONTROL DFIG TURBINE

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Pressure-Induced Pre-Lithiation Enables High-Performing Si Anodes in All-Solid-State Batteries

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 1-3页

作者： Hu, Weifei Li, Yuanyuan Liu, Jinping Wuhan univ Technol Sch Chem Chem Engn & Life Sci Wuhan 430070 Peoples R China Wuhan univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China Huazhong univ Sci & Technol Sch Integrated Circuits Wuhan 430074 Peoples R China

A commentary on pressure-induced pre-lithiation towards Si anodes in all-solid-state Li-ion batteries (ASSLIBs) using sulfide electrolytes (SEs) is presented. First, feasible pre-lithiation technologies for Si anodes in SE-based ASSLIBs especially the significant pressure-induced pre-lithiation strategies are briefly reviewed. Then, a recent achievement by Meng et al. in this field is elaborated in detail. Finally, the significance of Meng's work is discussed.

关键词： all-solid-state Li-ion batteries pre-lithiation pressure Si anode sulfide electrolyte

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Properties, hazards and valuable metal recovery technologies of red mud: A review

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PARTICUOLOGY 2024年第10期93卷 328-348页

作者： Du, Peixin Wang, Peng Zhang, Xueqian Wen, Guangwu Wang, Yishan Shandong univ Technol Sch Mat Sci & Engn Zibo 255000 Peoples R China

This review presents a summary of the research conducted thus far on the recovery of various types of valuable metals from red mud. The composition, properties, environmental hazards, and current status of comprehensive utilization of red mud were studied. A number of studies have been conducted on the use of red mud as a modifying additive for cement, the development of various catalysts based on red mud, and the recovery of various valuable metals from red mud. Furthermore, we examine several techniques for extracting various types of valuable metals from red mud, including pyrometallurgical recovery, wet leaching recovery, and emerging biobased technology recovery. We investigate the underlying principles, processes, research progress, and the potential for industrial application of these methods, and assess the advantages and disadvantages of each from the perspectives of economic and environmental benefits. Although these methods have certain disadvantages, in general, the recovery of various types of valuable metals from red mud is an effective way to solve the problem of red mud and the supply of metal raw materials. In conclusion, this paper presents an overview of the current state of red mud development and utilization, as well as the various methods employed for the recovery of valuable metals from red mud. (c) 2024 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Red mud Utilization Environment hazard Valuable metal Recovery LEACHING BEHAVIOR IRON RECOVERY ACID SEPARATION EXTRACTION REDUCTION MICROWAVE SCANDIUM ELEMENTS ORE

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Role of binders in reactive composites: A case study with spherical B/Pb 3 O 4 particles

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PARTICUOLOGY 2024年第10期93卷 170-179页

作者： Wang, Fan Du, Shanghao Yang, Jiahui Xue, Zhihua Li, Jiafei An, Chongwei Wang, Jingyu Wu, Bidong North univ China Sch Environm & Safety Engn Taiyuan 030051 Peoples R China

The strategic selection of appropriate preparation methods and binder strategies is crucial for enhancing the particle and combustion performance of pyrotechnic delay compositions (PDCs). This study, utilizing droplet microfluidics technology (DMT) and micron-scale raw materials, prepared spherical B/Pb 3 O 4 composite particles with varying concentrations of fluorine rubber (F 2604 ). The morphology, specific surface area, bulk density, flowability, friction sensitivity, thermal decomposition, and combustion performance of these microspheres were characterized. The results indicate that as the binder content increases, the particle size of the microspheres first decreases and then increases, the specific surface area decreases, and the bulk density increases, correlating with tighter binding of the reactant powders by the binder. Furthermore, tighter powder-to-powder binding results in a progressive decrease in the thermal decomposition peak temperature of the samples (from 404.2 degrees C to 346.4 degrees C). Additionally, increased binder content reduces the friction sensitivity and combustion rate of the samples, which is attributed to the energy absorption properties of the binder. Compared to the control group, the microsphere samples exhibit significantly enhanced bulk density, flowability, friction safety, and combustion delay precision, potentially improving the reliability of PDCs in ignition sequences. (c) 2024 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

关键词： Pyrotechnic delay composition Droplet microfluidic technology Particle Binder Combustion performance BURNING RATE DELAY

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Detection of transient mode-locking dynamics for a femtosecond Yb:KGW laser

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CHINESE OPTICS LETTERS 2024年第8期22卷 081402-081402页

作者： Liu, Huimin Tian, Jinrong Zhang, Zexin Liu, Haiyan Mao, Lin Song, Yanrong Beijing univ Technol Sch Phys & Optoelect Engn Beijing 100124 Peoples R China

The evolution dynamics of mode locking for a solid-state femtosecond Yb:KGW laser is demonstrated and detected with time-stretch dispersive Fourier transform (DFT) technique for the first time, to the best of our knowledge. The Yb:KGW laser is constructed first with a classical X-shaped cavity, and SESAM-assisted Kerr lens mode locking is obtained. Then, a DFT device is built to record the buildup and extinction dynamics of the mode-locked laser. The results suggest that the time of extinction is slightly shorter than the buildup time and both of them experience complex transitions. The results indicate that DFT could also be suitable to detect the transient buildup and extinction process in solid-state lasers, which would help investigate both the evolution of mode locking and characteristics determination for solid-state lasers.

关键词： dynamic process dispersive Fourier transform mode-locked solid-state laser SOLITON EXPLOSIONS SPECTROSCOPY

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Model-driven full system dynamics estimation of PMSM-driven chain shell magazine

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DEFENCE TECHNOLOGY 2024年第9期39卷 147-156页

作者： Wei, Kai Chen, Longmiao Zou, Quan NanJing univ Sci & Technol Sch Mech Engn Nanjing 210094 Peoples R China

Based on the system dynamic model, a full system dynamics estimation method is proposed for a chain shell magazine driven by a permanent magnet synchronous motor (PMSM). An adaptive extended state observer (AESO) is proposed to estimate the unmeasured states and disturbance, in which the model parameters are adjusted in real time. Theoretical analysis shows that the estimation errors of the disturbances and unmeasured states converge exponentially to zero, and the parameter estimation error can be obtained from the extended state. Then, based on the extended state of the AESO, a novel parameter estimation law is designed. Due to the convergence of AESO, the novel parameter estimation law is insensitive to controllers and excitation signal. Under persistent excitation (PE) condition, the estimated parameters will converge to a compact set around the actual parameter value. Without PE signal, the estimated parameters will converge to zero for the extended state. Simulation and experimental results show that the proposed method can accurately estimate the unmeasured states and disturbance of the chain shell magazine, and the estimated parameters will converge to the actual value without strictly continuous PE signals. (c) 2024 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： Chain shell magazine Full system dynamics estimation Disturbance estimation Parameter estimation Adaptive extended state observer PARAMETER-ESTIMATION NONLINEAR-SYSTEMS STATE

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Recyclable Technology of Thermosetting Resins for High Thermal Conductivity Materials Based on Physical Crushing

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ENERGY & ENVIRONMENTAL MATERIALS 2024年第6期7卷 378-387页

作者： Zhong, An Xie, Congzhen Gou, Bin Zhou, Jiangang Xu, Huasong Yu, Song Zhang, Daoming Bi, Chunhui Cai, Hangchuan Li, Licheng Wang, Rui South China univ Technol Sch Elect Power Guangzhou 510641 Peoples R China

Epoxy resin, characterized by prominent mechanical and electric-insulation properties, is the preferred material for packaging power electronic devices. Unfortunately, the efficient recycling and reuse of epoxy materials with thermally cross-linked molecular structures has become a daunting challenge. Here, we propose an economical and operable recycling strategy to regenerate waste epoxy resin into a high-performance material. Different particle size of waste epoxy micro-spheres (100-600 mu m) with core-shell structure is obtained through simple mechanical crushing and boron nitride surface treatment. By using smattering epoxy monomer as an adhesive, an eco-friendly composite material with a "brick-wall structure" can be formed. The continuous boron nitride pathway with efficient thermal conductivity endows eco-friendly composite materials with a preeminent thermal conductivity of 3.71 W m-1 K-1 at a low content of 8.5 vol% h-BN, superior to pure epoxy resin (0.21 W m-1 K-1). The composite, after secondary recycling and reuse, still maintains a thermal conductivity of 2.12 W m-1 K-1 and has mechanical and insulation properties comparable to the new epoxy resin (energy storage modulus of 2326.3 MPa and breakdown strength of 40.18 kV mm-1). This strategy expands the sustainable application prospects of thermosetting polymers, offering extremely high economic and environmental value. This manuscript reports the strategy to recycle waste epoxy resins into high thermal conductivity epoxy composites with brick-wall topology based on the physical recycling method. The ultralow content of BN (e.g., 8.5 vol%) endows the composite with record thermal conductivity of 3.71 W m-1 K-1 at the same volume fraction level. image

关键词： brick-wall structure epoxy thermosetting physical recycling thermal management DIELECTRIC-PROPERTIES EPOXY COMPOSITES WASTE MANAGEMENT PLASTICS NANOCOMPOSITE POLYMERS

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