Hongsheng Su, Lixia Dong^*, Xiaoying Yu, Kai Liu

Energy Engineering, Vol.121, No.4, pp. 973-986, 2024, DOI:10.32604/ee.2023.043497

Abstract Time based maintenance (TBM) and condition based maintenance (CBM) are widely applied in many large wind farms to optimize the maintenance issues of wind turbine gearboxes, however, these maintenance strategies do not take into account environmental benefits during full life cycle such as carbon emissions issues. Hence, this article proposes a carbon emissions computing model for preventive maintenance activities of wind turbine gearboxes to solve the issue. Based on the change of the gearbox state during operation and the influence of external random factors on the gearbox state, a stochastic differential equation model (SDE) and corresponding carbon emission model are… More > Graphic Abstract

Jian Zhong, Lei Zhang^*, Ling Qin

Energy Engineering, Vol.121, No.4, pp. 951-971, 2024, DOI:10.32604/ee.2023.041433

Abstract Partial shading conditions (PSCs) caused by uneven illumination become one of the most common problems in photovoltaic (PV) systems, which can make the PV power-voltage (P-V) characteristics curve show multi-peaks. Traditional maximum power point tracking (MPPT) methods have shortcomings in tracking to the global maximum power point (GMPP), resulting in a dramatic decrease in output power. In order to solve the above problems, intelligent algorithms are used in MPPT. However, the existing intelligent algorithms have some disadvantages, such as slow convergence speed and large search oscillation. Therefore, an improved whale algorithm (IWOA) combined with the P&O (IWOA-P&O) is proposed for… More >

Pu Zhang¹, Yingjun Li¹, Xinyu Zhu¹, Shizhan Xu¹, Pinwu Guan^1,*, Wei Liu², Yanwei Guo², Haibo Wang²

Structural Durability & Health Monitoring, Vol.18, No.2, pp. 143-159, 2024, DOI:10.32604/sdhm.2024.046986

Abstract Grouting defects are an inherent challenge in construction practices, exerting a considerable impact on the operational structural integrity of connections. This investigation employed the impact-echo technique for the detection of grouting anomalies within connections, enhancing its precision through the integration of wavelet packet energy principles for damage identification purposes. A series of grouting completeness assessments were meticulously conducted, taking into account variables such as the divergent material properties of the sleeves and the configuration of adjacent reinforcement. The findings revealed that: (i) the energy distribution for the high-strength concrete cohort predominantly occupied the frequency bands 42, 44, 45, and 47,… More >

Nikola Stosic^**, Ian K. Smith, Ahmed Kovacevic

Frontiers in Heat and Mass Transfer, Vol.3, No.2, pp. 1-7, 2012, DOI:10.5098/hmt.v3.2.3003

Abstract Due to fast rotation of screw compressor rotors, temperature is uniform in the rotor cross section and temperature field is a function of the axial coordinate only. Apart of that the rotors in one cross section the rotors are simultaneously heated by hot gas on one side while cooled at another side by cold gas. As a result of identification of the main modes of heat transfer both in the rotors and between the rotors and their surroundings and the relative significance of each, a novel procedure is suggested to cool the rotors by injection of minute quantities of a… More >

Haitao Liu^1,2,*, Jiaming Wang¹, Xiuliang Zhang¹, Yanji Jiang², Qian Xiao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 2747-2772, 2024, DOI:10.32604/cmes.2024.047129

Abstract The expansion chamber serves as the primary silencing structure within the exhaust pipeline. However, it can also act as a sound-emitting structure when subjected to airflow. This article presents a hybrid method for numerically simulating and analyzing the unsteady flow and aerodynamic noise in an expansion chamber under the influence of airflow. A fluid simulation model is established, utilizing the Large Eddy Simulation (LES) method to calculate the unsteady flow within the expansion chamber. The simulation results effectively capture the development and changes of the unsteady flow and vorticity inside the cavity, exhibiting a high level of consistency with experimental… More > Graphic Abstract

Jinlong Yang, Kwang-Hee Lee, Chul-Hee Lee^*

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 2917-2946, 2024, DOI:10.32604/cmes.2024.046740

Abstract Cavitation is a common issue in pumps, causing a decrease in pump head, a fall in volumetric efficiency, and an intensification of outlet flow pulsation. It is one of the main hazards that affect the regular operation of the pump. Research on pump cavitation mainly focuses on mixed flow pumps, jet pumps, external spur gear pumps, etc. However, there are few cavitation studies on external herringbone gear pumps. In addition, pumps with different working principles significantly differ in the flow and complexity of the internal flow field. Therefore, it is urgent to study the cavitation characteristics of external herringbone gear… More >

Kuosheng Jiang¹, Chengrui Han¹, Yasheng Chang^2,3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 3329-3352, 2024, DOI:10.32604/cmes.2024.046729

Abstract Angular contact ball bearings have been widely used in machine tool spindles, and the bearing preload plays an important role in the performance of the spindle. In order to solve the problems of the traditional optimal preload prediction method limited by actual conditions and uncertainties, a roller bearing preload test method based on the improved D-S evidence theory multi-sensor fusion method was proposed. First, a novel controllable preload system is proposed and evaluated. Subsequently, multiple sensors are employed to collect data on the bearing parameters during preload application. Finally, a multisensor fusion algorithm is used to make predictions, and a… More >

Xinci Zhou, Jin Zhu^*

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 2705-2727, 2024, DOI:10.32604/cmes.2024.046363

Abstract As the number of automated guided vehicles (AGVs) within automated container terminals (ACT) continues to rise, conflicts have become more frequent. Addressing point and edge conflicts of AGVs, a multi-AGV conflict-free path planning model has been formulated to minimize the total path length of AGVs between shore bridges and yards. For larger terminal maps and complex environments, the grid method is employed to model AGVs’ road networks. An improved bounded conflict-based search (IBCBS) algorithm tailored to ACT is proposed, leveraging the binary tree principle to resolve conflicts and employing focal search to expand the search range. Comparative experiments involving 60… More >

Yanzhong Sun¹, Xiaoni Du^1,*, Shufen Niu², Xiaodong Yang²

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 3287-3310, 2024, DOI:10.32604/cmes.2023.043589

Abstract Traditional email systems can only achieve one-way communication, which means only the receiver is allowed to search for emails on the email server. In this paper, we propose a blockchain-based certificateless bidirectional authenticated searchable encryption model for a cloud email system named certificateless authenticated bidirectional searchable encryption (CL-BSE) by combining the storage function of cloud server with the communication function of email server. In the new model, not only can the data receiver search for the relevant content by generating its own trapdoor, but the data owner also can retrieve the content in the same way. Meanwhile, there are dual… More >

Xiaodan Wang^1,*, Zheng Xie², Guiping Du³

International Journal of Mental Health Promotion, Vol.26, No.2, pp. 149-160, 2024, DOI:10.32604/ijmhp.2023.030755

Abstract Research purpose: This study implemented somatosensory music therapy on patients with depressive disorders, and explored the effects of somatosensory music therapy on the degree of depression, positive and negative emotions, intuitive stress and autonomic nervous function of patients. Research method: We collected 66 patients diagnosed with depression from the Department of Psychological Medicine of Henan Provincial People’s Hospital, and divided them into a control group and an intervention group according to the random number table, with 33 people in each group. The control group received routine psychiatric treatment and nursing. On the basis of the control group, the intervention group… More >