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  • Open Access

    ARTICLE

    Shale Fracturability Graphic Template Based on Mixed Analytic Hierar-chy Process and Mutation Theory

    Sichen Li1,2, Dehua Liu1,2,*, Liang Cheng1,2, Pan Ma1,2

    Energy Engineering, Vol.121, No.7, pp. 1921-1943, 2024, DOI:10.32604/ee.2024.049906

    Abstract Due to the depletion of conventional energy reserves, there has been a global shift towards non-conventional energy sources. Shale oil and gas have emerged as key alternatives. These resources have dense and heterogeneous reservoirs, which require hydraulic fracturing to extract. This process depends on identifying optimal fracturing layers, also known as ‘sweet spots’. However, there is currently no uniform standard for locating these sweet spots. This paper presents a new model for evaluating fracturability that aims to address the current gap in the field. The model utilizes a hierarchical analysis approach and a mutation model, More >

  • Open Access

    ARTICLE

    Arc Grounding Fault Identification Using Integrated Characteristics in the Power Grid

    Penghui Liu1,2,*, Yaning Zhang1, Yuxing Dai2, Yanzhou Sun1,3

    Energy Engineering, Vol.121, No.7, pp. 1883-1901, 2024, DOI:10.32604/ee.2024.049318

    Abstract Arc grounding faults occur frequently in the power grid with small resistance grounding neutral points. The existing arc fault identification technology only uses the fault line signal characteristics to set the identification index, which leads to detection failure when the arc zero-off characteristic is short. To solve this problem, this paper presents an arc fault identification method by utilizing integrated signal characteristics of both the fault line and sound lines. Firstly, the waveform characteristics of the fault line and sound lines under an arc grounding fault are studied. After that, the convex hull, gradient product,… More >

  • Open Access

    ARTICLE

    Carbon Emission Factors Prediction of Power Grid by Using Graph Attention Network

    Xin Shen1, Jiahao Li1, Yujun Yin1, Jianlin Tang2,3,*, Weibin Lin2,3, Mi Zhou2,3

    Energy Engineering, Vol.121, No.7, pp. 1945-1961, 2024, DOI:10.32604/ee.2024.048388

    Abstract Advanced carbon emission factors of a power grid can provide users with effective carbon reduction advice, which is of immense importance in mobilizing the entire society to reduce carbon emissions. The method of calculating node carbon emission factors based on the carbon emissions flow theory requires real-time parameters of a power grid. Therefore, it cannot provide carbon factor information beforehand. To address this issue, a prediction model based on the graph attention network is proposed. The model uses a graph structure that is suitable for the topology of the power grid and designs a supervised More >

  • Open Access

    ARTICLE

    Migratable Power System Transient Stability Assessment Method Based on Improved XGBoost

    Ying Qu1, Jinhao Wang1, Xueting Cheng1, Jie Hao1, Weiru Wang1, Zhewen Niu2, Yuxiang Wu2,*

    Energy Engineering, Vol.121, No.7, pp. 1847-1863, 2024, DOI:10.32604/ee.2024.048300

    Abstract The data-driven transient stability assessment (TSA) of power systems can predict online real-time prediction by learning the temporal features before and after faults. However, the accuracy of the assessment is limited by the quality of the data and has weak transferability. Based on this, this paper proposes a method for TSA of power systems based on an improved extreme gradient boosting (XGBoost) model. Firstly, the gradient detection method is employed to remove noise interference while maintaining the original time series trend. On this basis, a focal loss function is introduced to guide the training of… More >

  • Open Access

    ARTICLE

    An Innovative Technique to Measure Lateral Pressure of Self-Compacting Concrete Using Fiber Bragg Grating Sensor

    Pshtiwan Shakor1,2,*, Nadarajah Gowripalan3, Paul Rocker4

    Structural Durability & Health Monitoring, Vol.18, No.4, pp. 395-408, 2024, DOI:10.32604/sdhm.2024.049366

    Abstract Self-compacting concrete (SCC) is the most flowable concrete type that exerts high pressure on formwork. SCC is the most commonly used concrete globally for construction applications due to its cost-effectiveness. However, to make a formwork resist the exerted lateral pressure of SCC, it is required to have a suitable design for formwork. This paper presents a novel approach on how could create and prepare the Fiber Bragg Grating (FBG) optics using as a sensor to measure lateral pressure and temperature of SCC. To ensure the FBG sensor works properly a validated methodology is conducted. In More > Graphic Abstract

    An Innovative Technique to Measure Lateral Pressure of Self-Compacting Concrete Using Fiber Bragg Grating Sensor

  • Open Access

    ARTICLE

    Identification of Damage in Steel‒Concrete Composite Beams Based on Wavelet Analysis and Deep Learning

    Chengpeng Zhang, Junfeng Shi*, Caiping Huang

    Structural Durability & Health Monitoring, Vol.18, No.4, pp. 465-483, 2024, DOI:10.32604/sdhm.2024.048705

    Abstract In this paper, an intelligent damage detection approach is proposed for steel-concrete composite beams based on deep learning and wavelet analysis. To demonstrate the feasibility of this approach, first, following the guidelines provided by relevant standards, steel-concrete composite beams are designed, and six different damage incidents are established. Second, a steel ball is used for free-fall excitation on the surface of the steel-concrete composite beams and a low-temperature-sensitive quasi-distributed long-gauge fiber Bragg grating (FBG) strain sensor is used to obtain the strain signals of the steel-concrete composite beams with different damage types. To reduce the… More >

  • Open Access

    ARTICLE

    On the Features of Thermal Convection in a Compressible Gas

    Igor B. Palymskiy1,2,*

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 957-974, 2024, DOI:10.32604/fdmp.2024.048829

    Abstract The fully nonlinear equations of gas dynamics are solved in the framework of a numerical approach in order to study the stability of the steady mode of Rayleigh-Bénard convection in compressible, viscous and heat-conducting gases encapsulated in containers with no-slip boundaries and isothermal top and bottom walls. An initial linear temperature profile is assumed. A map of the possible convective modes is presented assuming the height of the region and the value of the temperature gradient as influential parameters. For a relatively small height, isobaric convection is found to take place, which is taken over… More >

  • Open Access

    ARTICLE

    Aerodynamic Analysis and Optimization of Pantograph Streamline Fairing for High-Speed Trains

    Xiang Kan1, Yan Li2, Tian Li1,*, Jiye Zhang1

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 1075-1091, 2024, DOI:10.32604/fdmp.2023.044050

    Abstract A pantograph serves as a vital device for the collection of electricity in trains. However, its aerodynamic resistance can limit the train’s running speed. As installing fairings around the pantograph is known to effectively reduce the resistance, in this study, different fairing lengths are considered and the related aerodynamic performances of pantograph are assessed. In particular, this is accomplished through numerical simulations based on the k-ω Shear Stress Transport (SST) two-equation turbulence model. The results indicate that the fairing diminishes the direct impact of high-speed airflow on the pantograph, thereby reducing its aerodynamic resistance. However, it More >

  • Open Access

    ARTICLE

    Evaluation of Well Spacing for Primary Development of Fractured Horizontal Wells in Tight Sandstone Gas Reservoirs

    Fang Li1,*, Juan Wu1, Haiyong Yi2, Lihong Wu2, Lingyun Du1, Yuan Zeng1

    FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 1015-1030, 2024, DOI:10.32604/fdmp.2023.043256

    Abstract Methods for horizontal well spacing calculation in tight gas reservoirs are still adversely affected by the complexity of related control factors, such as strong reservoir heterogeneity and seepage mechanisms. In this study, the stress sensitivity and threshold pressure gradient of various types of reservoirs are quantitatively evaluated through reservoir seepage experiments. On the basis of these experiments, a numerical simulation model (based on the special seepage mechanism) and an inverse dynamic reserve algorithm (with different equivalent drainage areas) were developed. The well spacing ranges of Classes I, II, and III wells in the Q gas More > Graphic Abstract

    Evaluation of Well Spacing for Primary Development of Fractured Horizontal Wells in Tight Sandstone Gas Reservoirs

  • Open Access

    ARTICLE

    An Intrusion Detection Method Based on a Universal Gravitation Clustering Algorithm

    Jian Yu1,2,*, Gaofeng Yu3, Xiangmei Xiao1,2, Zhixing Lin1,2

    Journal of Cyber Security, Vol.6, pp. 41-68, 2024, DOI:10.32604/jcs.2024.049658

    Abstract With the rapid advancement of the Internet, network attack methods are constantly evolving and adapting. To better identify the network attack behavior, a universal gravitation clustering algorithm was proposed by analyzing the dissimilarities and similarities of the clustering algorithms. First, the algorithm designated the cluster set as vacant, with the introduction of a new object. Subsequently, a new cluster based on the given object was constructed. The dissimilarities between it and each existing cluster were calculated using a defined difference measure. The minimum dissimilarity was selected. Through comparing the proposed algorithm with the traditional Back More >

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