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  • Open Access

    ARTICLE

    Experiments on the Start-Up and Shutdown of a Centrifugal Pump and Performance Prediction

    Yuliang Zhang1,2,*, Zezhou Yang1, Lianghuai Tong3,*, Yanjuan Zhao4, Xiaoqi Jia5, Anda Han6

    FDMP-Fluid Dynamics & Materials Processing, Vol.21, No.4, pp. 891-938, 2025, DOI:10.32604/fdmp.2024.059903 - 06 May 2025

    Abstract This paper investigates the start-up and shutdown phases of a five-bladed closed-impeller centrifugal pump through experimental analysis, capturing the temporal evolution of its hydraulic performances. The study also predicts the transient characteristics of the pump under non-rated operating conditions to assess the accuracy of various machine learning methods in forecasting its instantaneous performance. Results indicate that the pump’s transient behavior in power-frequency mode markedly differs from that in frequency-conversion mode. Specifically, the power-frequency mode achieves steady-state values faster and exhibits smaller fluctuations before stabilization compared to the other mode. During the start-up phase, as… More >

  • Open Access

    ARTICLE

    Exploring how pay fairness perception affects preschool teachers’ job performance in China: A moderated mediation analysis

    Xiaoying Zeng1,*, Ying Liu2, Yufei Li2, Yongping Yu2

    Journal of Psychology in Africa, Vol.35, No.1, pp. 91-97, 2025, DOI:10.32604/jpa.2025.065779 - 30 April 2025

    Abstract This study constructed a moderated mediation model to examine how the social support received by teachers is associated with their work pay fairness perception in relation to their job satisfaction and job performance. Data were collected from 2411 preschool teachers in China (female = 98.01%; mean age = 29.12 years, SD = 6.28 years). These data were analyzed using structural equation modelling, bootstrapping and latent moderate structural equations. The results indicated that teachers’ perception of pay fairness is directly associated with self-rated job performance. Additionally, pay fairness perceptions have an indirect effect on higher job More >

  • Open Access

    ARTICLE

    Leaders’ expectations of innovation and employees’ innovative behavior: The roles of employees’ expected positive performance outcomes and innovative self-efficacy

    Qian Ma1, Hao Zhou2,*

    Journal of Psychology in Africa, Vol.35, No.1, pp. 7-19, 2025, DOI:10.32604/jpa.2025.065775 - 30 April 2025

    Abstract Employees’ innovative performance determines an organization’s innovation, which critically impacts its structural optimization and sustainability. Applying expectancy theory, we examined how and when the Pygmalion effect occurs in the relationship between leaders’ expectations of innovation and employee innovative behavior. Our sample comprised 201 frontline employees (female = 31.84%; mean age = 41.48 years, SD = 7.97 years) in a Chinese coal enterprise, who completed surveys on innovation expectations of leaders, expected positive performance outcomes, innovative self-efficacy and innovative behavior. The results revealed that employees’ expected positive performance outcomes mediated the positive relationship between leaders’ innovation More >

  • Open Access

    ARTICLE

    When Parents Worry: How Parental Educational Anxiety Impacts Adolescent Academic Success through Depression, Self-Efficacy, and Social Media

    Haohan Zhao1, Xingchen Zhu2, Wencan Li3,*, Xin Lin4,*

    International Journal of Mental Health Promotion, Vol.27, No.4, pp. 517-540, 2025, DOI:10.32604/ijmhp.2025.062739 - 30 April 2025

    Abstract Background: Despite increasing attention to parental educational anxiety in China’s educational system, the underlying mechanisms through which this anxiety affects adolescent academic performance remain unclear. This study aims to investigate how parental educational anxiety influences academic outcomes through depression and self-efficacy while considering the role of problematic social media use in today’s digital age. Methods: Data analysis was conducted using stratified random cluster sampling techniques. Participants for this study were recruited from middle and high schools in China. The sample comprised 2579 traditional two-parent families, each consisting of a pair of parents and one child.… More >

  • Open Access

    ARTICLE

    The Effect of Performance Pressure on Employee Well-Being: Mediator of Workplace Anxiety and Moderator of Vocational Delay of Gratification

    Ting Wen1, Sainan Mao1, Xiaoqian Fan2,*, Jiayi Wu3

    International Journal of Mental Health Promotion, Vol.27, No.4, pp. 591-606, 2025, DOI:10.32604/ijmhp.2025.057726 - 30 April 2025

    Abstract Background: In the field of organizational behavior, various aspects that have an impact on employee well-being gradually become a focus of attention. Among them, performance pressure, which is a component of workplace stressors that has a great influence on employees’ job performance as well as well-being, has been little studied. Therefore, this paper constructs a research model, which uses workplace anxiety as a mediating variable and vocational delay of gratification as a moderating variable, to explore the impact of performance pressure on employee well-being. Methods: Reliable data were collected by questionnaire method and data analysis… More >

  • Open Access

    ARTICLE

    Evaluating Dying Efficiency and Energy Performance of a Hybrid Solar Dryer with Natural, Forced, and Hybrid Convection Modes for Tomatoes

    Sadaf Gul Unar1, Shoaib Ahmed Khatri1,*, Nayyar Hussain Mirjat1, Muhammad Faraz Arain1, Syed Rafay Ahmed Zaidi1, Laveet Kumar2

    Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 479-505, 2025, DOI:10.32604/fhmt.2025.063937 - 25 April 2025

    Abstract This research focuses on developing innovative hybrid solar dryers that combine solar Photovoltaic (PV) and solar thermal systems for sustainable food preservation in Pakistan, addressing the country’s pressing issues of high post-harvest losses and unreliable energy sources. The proposed active hybrid solar dryer features a drying cabinet, two Direct Current (DC) fans for forced convection, and a resistive heating element powered by a 180 W solar PV panel. An energy-storing battery ensures continuous supply to the auxiliaries during periods of low solar irradiance, poor weather conditions, or nighttime. Tomatoes, a delicate and in-demand crop, were… More >

  • Open Access

    ARTICLE

    Enhancement of Thermal Performance of Counter Flow Double Pipe Heat Exchanger by Inserting Wavy-Edged Tape

    Zainab Mahdi Saleh1,*, Riyadh S. Al-Turaihi1, Zena Khalefa Kadhim2

    Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 615-650, 2025, DOI:10.32604/fhmt.2025.063404 - 25 April 2025

    Abstract This study involved numerical simulations of a double tube heat exchanger using the ANSYS FLUENT program version 22. The study aims to examine methods for minimizing pressure loss and consequently enhancing the thermal performance index (TPI) of a heat exchanger fitted with wavy edge tape that is a heat recovery system (the hot air in simulation instead of t heat from the exhaust gases of the brick factory furnaces and return it to warm the heavy fuel oil by substituting the electrical heater with a heat exchanger to recuperate waste heat from the flue gases,… More >

  • Open Access

    ARTICLE

    Numerical Study of Multi-Factor Coupling Effects on Energy Conversion Performance of Nanofluidic Reverse Electrodialysis

    Hao Li1, Cunlu Zhao2, Jinhui Zhou1, Jun Zhang3, Hui Wang1, Yanmei Jiao1,*, Yugang Zhao4,5,*

    Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 507-528, 2025, DOI:10.32604/fhmt.2025.063359 - 25 April 2025

    Abstract Based on the rapid advancements in nanomaterials and nanotechnology, the Nanofluidic Reverse Electrodialysis (NRED) has attracted significant attention as an innovative and promising energy conversion strategy for extracting sustainable and clean energy from the salinity gradient energy. However, the scarcity of research investigating the intricate multi-factor coupling effects on the energy conversion performance, especially the trade-offs between ion selectivity and mass transfer in nanochannels, of NRED poses a great challenge to achieving breakthroughs in energy conversion processes. This numerical study innovatively investigates the multi-factor coupling effect of three critical operational factors, including the nanochannel configuration,… More >

  • Open Access

    ARTICLE

    Optimizing Solar Air Heater Performance Using Perforated V-Shaped Barriers with Varied Geometric Designs

    Sajjad Tariq A. Shafi, Mohammed K. Al-Saadi, Ameer Abed Jaddoa*

    Frontiers in Heat and Mass Transfer, Vol.23, No.2, pp. 703-719, 2025, DOI:10.32604/fhmt.2025.063118 - 25 April 2025

    Abstract To improve the heat transfer rate and thermal performance of the solar air heater due to low efficiency, new techniques, such as artificial roughness, barriers, and obstacles, should be used to increase the heat exchange between the fluid and the absorber. In this research, perforated V-shaped blockages with new geometric shapes, which are circular, hexagonal, square, rectangular, and triangular, were used. They were fixed on the absorber plate inside the channel with dimensions of 1.5 m × 0.5 m × 0.05 m, which increased the exit temperature of the air passing through the channel. The… More > Graphic Abstract

    Optimizing Solar Air Heater Performance Using Perforated V-Shaped Barriers with Varied Geometric Designs

  • Open Access

    ARTICLE

    Numerical Investigation to Enhance the Solar Collector Performance Using Nano-Encapsulated Octadecane Organic Paraffin PCM

    Malik A. Faisal*, Alireza Saraei

    Energy Engineering, Vol.122, No.5, pp. 2099-2117, 2025, DOI:10.32604/ee.2025.061569 - 25 April 2025

    Abstract Performance enhancement of flat plate solar collectors is an endless research direction as it represents the most used solar technology. The enhancement could be achieved via design alteration, absorber-installed protrusions, and integration with thermal energy storage. The objective of the current research is to evaluate a compacted solar collector integrated with octadecane organic paraffin PCM (phase change materials) as a thermal energy storage medium. The investigations have been performed numerically utilizing ANSYS software. Thermal storage contains the PCM securely encased behind the absorbent plate of the collector in four packing containers. The investigations have been… More >

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