Utility System Research Articles

SYSTEMATIC LITERATURE REVIEW: SERVANT LEADERSHIP IN PUBLIC SECTORS

Servant leadership delivers important reforms to the increasingly complex public utility system. This systematic review seeks to incorporate the latest six years of articles on geographic divisions, conceptual definitions, measuring techniques, theoretical frameworks, and nomological networks (antecedents, mediators, outcomes, and moderators) in the public sector. The risk of bias was evaluated using the Cochrane Risk of Bias Tool and ROBINS-I, and employing automated techniques such as Rayyan for screening. Using PRISMA’s review approach, this comprehensive synthesis of 51 relevant public sector-specific conceptual and empirical studies across six academic electronic databases (Taylor & Francis, Sage, Scopus, Springer Link, Web of Science, and Wiley) shows that servant leadership is critical for establishing a prosocial workforce. This review discovered that the global construct of servant leadership (SL-7) scale has been the most often utilised measure of servant leadership in public sector-specific studies recently. Social exchange theory remains the predominant explanation for the impact of servant leadership on specific variables. The findings also illustrate a generally positive influence of servant leadership. Moreover, this review provides limitations and suggestions for future studies by summarising elements that have received less attention.

A comprehensive review of lignin-reinforced lignocellulosic composites: Enhancing fire resistance and reducing formaldehyde emission.

The rising environmental concerns and the growing demand for renewable materials have surged across various industries. In this context, lignin, being a plentiful natural aromatic compound that possesses advantageous functional groups suitable for utilization in biocomposite systems, has gained notable attention as a promising and sustainable alternative to fossil-derived materials. It can be obtained from lignocellulosic biomass through extraction via various techniques, which may cause variability in its thermal, mechanical, and physical properties. Due to its excellent biocompatibility, eco-friendliness, and low toxicity, lignin has been extensively researched for the development of high-value materials including lignin-based biocomposites. Its aromatic properties also allow it to successfully substitute phenol in the production of phenolic resin adhesives, resulting in decreased formaldehyde emission. This review investigated and evaluated the role of lignin as a green filler in lignin-based lignocellulosic composites, aimed at enhancing their fire retardancy and decreasing formaldehyde emission. In addition, relevant composite properties, such as thermal properties, were investigated in this study. Markedly, technical challenges, including compatibility with other matrix polymers that are influenced by limited reactivity, remain. Some impurities in lignin and various sources of lignin also affect the performance of composites. While lignin utilization can address certain environmental issues, its large-scale use is limited by both process costs and market factors. Therefore, the exact mechanism by which lignin enhances flame retardancy, reduces formaldehyde emissions, and improves the long-term durability of lignocellulosic composites under various environmental conditions remains unclear and requires thorough investigation. Life cycle analysis and techno-economic analysis of lignin-based composites may contribute to understanding the overall influence of systems not only at the laboratory scale but also at a larger industrial scale.

Thermal performance analysis of a deep coaxial borehole heat exchanger with a horizontal well based on a novel semi-analytical model

This study introduces a novel semi-analytical model for deep coaxial borehole heat exchanger with a horizontal well(H-DBHE), which incorporates the effects of formation stratification and transient heat conduction within the pipe walls. Initially, the model's validity was checked through a comparison with the results derived from the published numerical models. This semi-analytical approach significantly reduces computational time while ensuring calculation accuracy. Subsequently, the study quantitatively examined the influence of the operation parameters, structural characteristics and the thermal capacity within the borehole on the dynamic heat extraction of H-DBHE. The numerical results demonstrate that the thermal capacity within the borehole significantly influences the heat extraction performance during intermittent operations of H-DBHE. Based on this finding, the study further investigated the effects of intermittent operation and heating time on the heat recovery performance of the system. Additionally, the study compared the long-term operational performance and thermal attenuation between H-DBHE and deep coaxial borehole heat exchanger (DBHE) over a ten-year simulation period. This research introduces a novel semi-analytical model for H-DBHE, which is of significant theoretical guidance for accurately predicting the heat extraction performance of H-DBHE and scientifically designing geothermal utilization systems.

Optimal power utilization in hybrid microgrid systems with IoT-based battery-sustained energy management using RSA-PFGAN approach

The quantity of power electronics converters that interface with the various components of a hybrid microgrid system has a major impact on its efficiency. Minimizing power conversion stages and increasing system efficiency requires integrating a photovoltaic system with micro grids while maximizing the number of converters. This paper presents a hybrid approach for utilizing power in microgrid system with an Internet of Things (IoT) based battery sustained energy management scheme. The proposed hybrid technique combines the Reptile Search Algorithm (RSA) and Progressive Fusion Generative Adversarial Network (PFGAN). Thus, it is referred to as the RSA-PFGAN technique. The principal aim of the proposed approach is to minimize operating costs, improve voltage profiles, and reduce computation time and errors. The discharging and charging strategy of the battery is optimized by the RSA approach. The load demand is predicted using the PFGAN approach. Using MATLAB, the proposed method is evaluated and contrasted to other existing methods. The proposed approach determines better outcomes contrasted to existing techniques such as Wild Horse Optimization (WHO), Particle Swarm Optimization (PSO) and Seeker Optimization Algorithm (SOA). The proposed method achieves an efficiency of 85 %, significantly higher than the PSO's 55 %, WHO's 65 %, and SOA's 75 %. Additionally, the proposed approach exhibits a computation time of just 0.21 s, demonstrating its efficiency compared to PSO at 2.95 s, WHO at 0.87 s, and SOA at 0.43 s. These results indicates that the RSA-PFGAN method offers better performance in terms of cost, efficiency, and computation time for hybrid microgrid systems.

Advanced exergy analysis of a novel mass integration cogeneration system driven by geothermal energy

To mitigate fossil energy consumption and increase renewable energy use, a novel mass integration cogeneration system (MICS) driven by geothermal energy is proposed in this work. Parametric evaluations are conducted in order to ascertain crucial system parameters. The system is analyzed thermodynamically utilizing exergy analysis and advanced exergy analysis. The findings indicate a direct relationship between the refrigeration coefficient of performance and the power generation efficiency, as well as the mass flow rate of the working fluid, the turbine input pressure, the valve outlet pressure, and the mass fraction of the working fluid at the generator outlet. Exergy analysis reveals that the exergy efficiency of the MICS is greater than 0.85. The condenser exhibits the highest exergy destruction, amounting to 54.52 kW. Given that around 40 % of exergy destruction in power consumption devices (such as turbines, compressors, and pumps) is preventable, there is significant potential for improvement. Furthermore, the MICS employs 50 % less working fluid compared to a heat integration cogeneration system. The implementation of advanced exergy analysis in this study will facilitate the progress of geothermal energy utilization systems, while the investigation of optimization possibilities will assist in their practical deployment in the industry.

Near-field thermal radiation between SiO2/Weyl semimetal multilayers

Weyl semimetals (WSMs) have attracted increasing attention due to their intrinsic anomalous Hall effect and the chiral anomalous effect. In this paper, we investigate the near-field radiative heat transfer (NFRHT) between two SiO2/WSM multilayers. We find that, the SiO2/WSM multilayers support hybrid photon modes, which enable a higher heat flux than the WSM configuration and the SiO2 configuration as well. The tunable number of Weyl nodes and Fermi level of the WSM plates empower the heat transfer coefficient (HTC) to be dynamically controlled. In addition, regarding the influence of the geometry, there exists a tradeoff in terms of the dependence of filling ratio, and a larger period number is adverse to the improvement of NFRHT. We hope that our work will be beneficial for thermal management and energy utilization in nanoscale multilayer WSM-based systems.

Capacity configuration optimization of regenerative braking energy utilization system for electrified railways based on power sharing and energy storage

The full utilization of regenerative braking energy (RBE) within the railway traction power supply system (TPSS) is of great significance for railway energy conservation and power grid safety. The traditional railway traction power supply system adopts a segmented structure, and achieving efficient utilization of RBE between adjacent traction substation (TS) is a challenge. This paper proposes an RBE utilization system (RBEUS) based on railway power regulator (RPC) and hybrid energy storage system (HESS), which achieves efficient utilization of RBE between adjacent TS and maximum demand reduction of TPSS through power sharing and energy storage. A power flow control strategy based on state machine logic is proposed, and the energy scheduling reference values of RPC and HESS under different typical operating conditions are calculated. By analyzing the mathematical relationship between the costs and benefits of RBEUS, a multi constraint RBEUS lifecycle net profit optimization model is established. The optimal capacity configuration of RBEUS is obtained by using an improved beluga whale optimization algorithm with the goal of maximizing the total net income of two TSs. The advantages of the proposed method in terms of RBE utilization and economic benefits are verified through engineering case analysis and scheme comparison.

Beneficial effects of Saccharomyces cerevisiae fermentation postbiotic products on calf and cow health and plausible mechanisms of action

Supplementation of cattle diets with Saccharomyces cerevisiae fermentation products (SCFP) has been shown to improve health and performance of calves and cows in both the dairy and feedlot. Numerous studies have shown SCFP supplementation is beneficial in the context of production- and infection-related stressors, promoting resilience, accelerated resolution of inflammation or oxidative stress, and enabling the cow or calf to maintain homeostasis. SCFPs, derived from yeast fermentation, encompass a rich array of bioactive compounds, including vitamins, minerals, amino acids, and metabolites, which likely influence the host through both distinct and overlapping processes. Understanding the mechanisms by which SCFPs exert their beneficial effects is crucial for optimizing their utilization in cattle production systems. In this review, we focused not only on the beneficial effects of SCFPs on health and performance but also on their influence on host microbiota, epithelial barrier integrity, and the host immune system, providing mechanistic insights. Previous studies have suggested that SCFPs impact host metabolism, modulate rumen and hindgut microbial populations, exert antioxidant and immunomodulatory effects, and stimulate the expression of genes involved in maintaining tissue barrier integrity. However, there are still gaps in understanding certain mechanistic pathways, particularly those involving the nervous system, as well as the paradoxical effects of SCFPs in enhancing immune responses while simultaneously mitigating excessive inflammation. This review summarizes several recent reports describing the health benefits of SCFP supplementation in cattle and considers the available evidence on the mode of action.

NaCl-KCl-CaCl2 molten salts for high temperature heat storage: Experimental and deep learning molecular dynamics simulation study

The thermal energy storage system based on molten salts plays a crucial role in renewable energy utilization and power grid regulation system. This article investigates NaCl-KCl-CaCl2 molten salts for high temperature heat storage by experimental measurement and deep learning molecular dynamics simulations. The phase transition, thermal stability, and thermophysical properties of NaCl-KCl-CaCl2 were experimental analyzed, and the results indicate that it has high enthalpy of 251.37 J/g, with observable evaporation at temperatures above 1103 K. An accurate deep potential model was further trained based on ab initio molecular dynamics data, achieving a root mean square error of 0.50 meV/atom for energy and 15.31 meV/Å for force, and the experimental and computational results for density and viscosity have discrepancies of less than 5 %. Based on experimental and simulation data, correlation equations for thermophysical properties of NaCl-KCl-CaCl2 were conducted, and thermal performance changes with temperature were further explained from the perspective of structural changes. As the temperature rises, all ionic pairs transfer to lower coordination numbers and disperse into smaller clusters, which results in the decreases of density, thermal conductivity and viscosity, and the stability of molten salt gradually decreases as the energy barriers for ion pairs dropping.

Waste Heat Utilization in Marine Energy Systems for Enhanced Efficiency

The maritime industry, central to global trade, faces critical challenges related to energy efficiency and environmental sustainability due to significant energy loss from waste heat in marine engines. This review investigates the potential of waste heat recovery (WHR) technologies to enhance operational efficiency and reduce emissions in marine systems. By analyzing major WHR methods, such as heat exchangers, Organic Rankine Cycle (ORC) systems, thermoelectric generators, and combined heat and power (CHP) systems, this work highlights the specific advantages, limitations, and practical considerations of each approach. Unique to this review is an examination of WHR performance in confined marine spaces and compatibility with existing ship components, providing essential insights for practical implementation. Findings emphasize WHR as a viable strategy to reduce fuel consumption and meet environmental regulations, contributing to a more sustainable maritime industry.

Empowering microgrids for sustainable transportation electrification: A comprehensive methodology for resource adequacy and grid resilience

Transportation electrification has emerged as a pivotal solution to mitigate carbon emissions from the transportation sector. However, this shift towards electric vehicles (EVs) presents significant challenges for municipalities and utilities, particularly in ensuring the electrical grid's capacity to meet the increased demand. In this sense, this work introduces a novel methodology to address these challenges by 1) quantifying the impact of EVs on the hosting capacity (HC) of residential microgrids (MGs), and 2) proposing a novel control strategy to meet grid resource adequacy requirements under high levels of transportation electrification. For this, first, a simplified approach to quantify the overall demand in residential MGs, accounting for the influence of EVs and typical demand profiles based on real-world data from municipalities and utility systems is developed. Second, a new frequency controller is introduced, utilizing Distributed Phasor Measurement Units (D-PMU) and mobile energy sources (MES) to ensure compliance with resource adequacy requirements under high levels of EVs penetration. The proposed controller takes advantage of the low latency and high-resolution capabilities of D-PMU technology to enable the harnessing of MES, preventing critical frequency nadir events, and improving the overall system resource adequacy performance under both transient and steady-state analysis. Real-world data from Seattle, WA, USA, is used in the developed case studies, and comparative analysis between traditional SCADA, state-of-the-art D-PMU-based controller, and the proposed controller is presented. The obtained results indicate that significant improvements are achieved by the proposed controller, empowering utilities to ensure reliable operations amidst transportation electrification challenges imposed on resource adequacy.

Numerical Simulation of Corrosive Flow in the Production End of Carbon Capture, Utilization, and Storage-Enhanced Oil Recovery Backflow Wastewater Pipeline

In a carbon capture, utilization, and storage-enhanced oil recovery (CCUS-EOR) system process, the high carbon dioxide content and high acid value of the fluid at the extraction end are treated at the wastewater treatment station and then flow through the transfer station of the gathering system. The reinjection system’s pipelines at the transfer station are prone to corrosion and leakage risks. A steady-state nonisothermal flow and corrosion model was established to examine this corrosive phenomenon by utilizing the principles of fluid dynamics and electrochemical corrosion. The study examined how flow velocity, temperature, pressure, and pH affected the pipeline’s corrosion. Simulation results showed flow velocity increased in specific places of both straight and curved pipeline sections. The velocity near the inner wall of curved portions was higher, making them more susceptible to cavitation damage. Faster flow rates, lower pH values, higher temperatures, and smaller pipeline diameters all contributed to increased corrosion on the inner walls of wastewater pipelines. The highest simulated corrosion rate was 8.3162 mm/a corresponding to the smallest pipeline diameter (100 mm), lowest pH (4), highest temperature (60°C), and highest flow rate (36.847 m/s). When designing the CCUS-EOR system, the nonmetallic pipeline should be given priority. If carbon steel metal pipelines are utilized, it is best to use larger-diameter materials in the engineering design. Additionally, procedures such as adding corrosion inhibitors to regulate pH values and lowering the temperature of wastewater conveyance might be explored to reduce corrosion on the pipeline’s inner walls.

Energy, exergy, and economic analysis of a novel solar-assisted ejector subcooling CO2 transcritical refrigeration systemt

To further enhance the performance of transcritical CO2 refrigeration cycle (base cycle), a solar-assisted ejector subcooling transcritical CO2 refrigeration cycle (SESRS) is proposed. The base cycle is subcooled utilizing a solar-assisted ejector refrigeration cycle. This research performed energy, exergy, and economic evaluations of SESRS utilizing the eco-friendly refrigerant R152a in the ejector cycle based on the established model. The thermodynamic analysis results demonstrate that SESRS outperform the base cycle. At typical working conditions, the COPm of the SESRS demonstrates a 22.96 % increase compared to that of the base cycle. Although the total cost of the SESRS is 7.98 %–17.9 % higher than that of the base cycle when subcooling degree is 5 °C, the enhancement of COPm is larger and is increased by approximately 18.34 %–26.22 %. The impact of subcooling degree and other parameters on system performance are also investigated. Overall, this study confirms the potential of the SESRS system for utilization in the refrigeration and air-conditioning fields. Considering both the system’s performance and economy, further optimized analysis should be done on key operational parameters, such as subcooling degree and discharge pressure.

Emerging breakthroughs in membrane filtration techniques and their application in agricultural wastewater treatment: Reusability aspects

Freshwater resources are becoming limited and are rapidly getting polluted due to industrialization and urbanization. Water pollution is a pervasive global challenge both in terms of scarcity and quality. Among other sources, wastewater discharged through agricultural practices are major contributor to environmental pollution. The leading cause of contaminants is the runoff of fertilizers, herbicides, insecticides and animal waste into waterbodies. Conventional treatment methods efficiently remove large particles, organic matter, and nutrients but require extensive infrastructure and produce significant sludge. In contrast, membrane filtration offers superior purification and reuse potential by using semi-permeable membranes to selectively remove contaminants, including suspended solids and dissolved ions. This study examines membrane filtration principles and technologies, emphasizing their role in delivering high-quality effluent for discharge or reuse. The study identifies fertilizers, herbicides, and insecticides as major agricultural contaminants and highlights conventional techniques' ineffectiveness in achieving high purification levels. Membrane filtration effectively remediates a wide range of pollutants, but fouling remains a challenge, addressed by antifouling agents and advanced membrane materials in hybrid processes. The study concludes by highlighting the reusability aspect of membrane filtration in agricultural systems and the potential applications of reclaimed water. This study emphasizes the need for advanced membrane materials and integrated systems for effective utilisation of membrane filtration.

Wood and Wood-Based Materials in Space Applications—A Literature Review of Use Cases, Challenges and Potential

Current political and sociological efforts to respond to the need for more environmentally friendly technologies have inspired a revival of wood and wood-based material utilization in space systems. The popularity of these materials has faded since their widespread use in the early days of aerospace engineering. This work reviews the literature to provide an overview of use cases, the motivation for using wood and wood-based materials and the challenges involved. A small number of applications were identified in which wood and wood-based materials were preferred over non-renewable raw materials. They are mainly applied for less-stressed disposable components or as a thermal protection material. It can be shown that the applied wooden materials have advantages such as low production costs, easy availability, easy and environment-friendly decomposition and low weight. However, only a limited number of applications have achieved a high level of technological readiness so far. Properties such as anisotropy and a lack of uniformity, defects in wood, the quantity available material and a lack of standards for the certification of wooden materials represent challenges. These are addressed in the current research, which additionally focuses on sustainable growth, enhanced environmental friendliness and advanced lightweight design.

Dependence of cyanobacterium growth and Mars-specific photobioreactor mass on total pressure, pN2 and pCO2

In situ resource utilization systems based on cyanobacteria could support the sustainability of crewed missions to Mars. However, their resource-efficiency will depend on the extent to which gases from the Martian atmosphere must be processed to support cyanobacterial growth. The main purpose of the present work is to help assess this extent. We therefore start with investigating the impact of changes in atmospheric conditions on the photoautotrophic, diazotrophic growth of the cyanobacterium Anabaena sp. PCC 7938. We show that lowering atmospheric pressure from 1 bar down to 80 hPa, without changing the partial pressures of metabolizable gases, does not reduce growth rates. We also provide equations, analogous to Monod’s, that describe the dependence of growth rates on the partial pressures of CO2 and N2. We then outline the relationships between atmospheric pressure and composition, the minimal mass of a photobioreactor’s outer walls (which is dependent on the inner-outer pressure difference), and growth rates. Relying on these relationships, we demonstrate that the structural mass of a photobioreactor can be decreased – without affecting cyanobacterial productivity – by reducing the inner gas pressure. We argue, however, that this reduction would be small next to the equivalent system mass of the cultivation system. A greater impact on resource-efficiency could come from the selection of atmospheric conditions which minimize gas processing requirements while adequately supporting cyanobacterial growth. The data and equations we provide can help identify these conditions.

Research on control strategy of electric vehicle thermal management system motor

Abstract The low efficiency and difficulty in low-temperature heating are the challenges currently faced by the thermal management system of new energy vehicles. A multi-heat source vehicle thermal management system for waste heat cascade recovery and utilization was proposed, and the performance of the vehicle thermal management system was studied through a combination of component testing and one-dimensional simulation. Based on a one-dimensional simulation model, the characteristics of the motor waste heat source are analyzed. The increase in the inlet water temperature of the motor coolant will lead to enhanced heat dissipation of the motor to the air, resulting in a waste of motor waste heat. Based on the results of the analysis, an energy cascade management strategy is constructed. The optimal heating mode is selected by collecting temperature signals such as motors, and the cut-off valve is controlled through logic gates to achieve flexible switching of different modes. The system effectively reduces the energy consumption of thermal management systems, which is of great significance for developing thermal management systems for new energy vehicles.

Evaluating membranes for hydrogen storage and utilization in next-generation aviation systems

This study aims to provide a comprehensive evaluation of membrane technologies for hydrogen-related processes in aviation, specifically focusing on hydrogen production, hydrogen separation, and fuel cells. As aviation seeks to transition to cleaner energy solutions, the selection of appropriate membranes is critical for ensuring efficiency and sustainability. The research utilizes the Analytic Hierarchy Process (AHP) to systematically assess membrane alternatives based on key criteria: economic factors, environmental impact, technical performance, and technological maturity. By conducting pairwise comparisons and detailed matrix calculations, this study establishes the relative importance of sub-criteria and ranks membrane types for each hydrogen-related application. The analysis identifies Nonporous Dense Films as the most effective membrane for hydrogen production, due to their balance of cost and technical performance. For hydrogen separation, Ceramic and Metal Membranes are determined to be the optimal choice, offering superior durability, hydrogen permeability, and thermal stability. In fuel cell applications, Electrically Charged Membranes are found to be the most suitable for Proton Exchange Membrane Fuel Cells (PEMFCs), while Ceramic and Metal Membranes excel in Solid Oxide Fuel Cells (SOFCs). The outcomes of this study not only highlight the most suitable membranes for different aviation hydrogen processes but also offer a strategic framework for decision-makers. By identifying the key factors driving membrane selection, this research contributes to advancing hydrogen adoption in aviation, facilitating the development of efficient, low-emission technologies for the future of sustainable air travel.

Edge Computing and Analytics for IoT Devices: Enhancing Real-Time Decision Making in Smart Environments

This article presents a comprehensive analysis of edge computing and analytics for Internet of Things (IoT) devices, addressing the growing need for real-time processing and reduced latency in IoT applications. We explore the evolution of IoT architectures, from cloud-centric models to edge-enabled systems, and examine the key components and data flows in edge computing environments. Through a detailed comparison of cloud and edge processing, we demonstrate significant latency reductions across various IoT scenarios, with improvements from hundreds of milliseconds to mere milliseconds. The article delves into crucial aspects of data management in edge computing, including local versus cloud processing trade-offs, data synchronization strategies, and privacy considerations. A case study of an edge analytics pipeline in a smart factory setting showcases practical implementations, revealing substantial improvements in anomaly detection speed, bandwidth utilization, and overall system efficiency. The case study achieved a 92.5% reduction in anomaly detection latency and an 85% decrease in bandwidth usage. Finally, we discuss ongoing challenges and future directions in edge computing, including scalability issues, standardization efforts, and the integration of emerging technologies such as 5G and AI accelerators. This article contributes to the growing body of knowledge on edge computing in IoT, offering insights into its transformative potential for creating more responsive and intelligent systems across diverse applications.

Cold plasma-activated Ni-Co tandem catalysts with CN vacancies for enhancing CH4 electrocatalytic to methyl formate

The direct electrooxidation of methane (CH4OR) into high value-added liquid products has been considered an effective method to efficient and clean utilization of methane. However, this process is mainly limited by CH4 activation and subsequent intermediate regulation. Here, we report the first successful achieve methyl formate from CH4OR on Ni-Co tandem catalysts with CN vacancies prepared by H2 cold plasma. The faradaic efficiency of CH4OR into methyl formate reaches 56.7 % at 2.0 V vs. RHE with remained stability for 160 h. In situ ATR-SEIRAS and DFT calculations suggest that the CN vacancies can shift the d-band center of the active Ni sites upwards to enhance the chemisorption of CH4 over Ni atom near CN vacancy, generating the key intermediates of *CH3 and *CH2. *CH2 further overflows onto the Co atom around the same CN vacancy, providing favorable conditions for esterification reaction to obtain methyl formate. This work opens a new avenue for the development of efficient electrocatalytic systems for the clean utilization of methane and the electrosynthesis of methyl formate under ambient conditions.