Search Results (9,261)

Lithium-ion capacitors (LICs) are emerging as promising hybrid energy storage devices that combine the high energy densities of lithium-ion batteries (LIBs) with high power densities of supercapacitors (SCs). Nevertheless, the development of LICs is hindered by the kinetic imbalances between battery-type anodes and capacitor-type cathodes. To address this issue, honeycomb-like N-doped carbon matrices encapsulating Co_1−xS/Co(PO₃)₂ heterostructures were prepared using a simple chemical blowing-vulcanization process followed by phosphorylation treatment (Co_1−xS/Co(PO₃)₂@NC). The Co_1−xS/Co(PO₃)₂@NC features a unique heterostructure engineered within carbon honeycomb structures, which efficiently promotes charge transfer at the interfaces, alleviates the volume expansion of Co-based materials, and accelerates reaction kinetics. The optimal Co_1−xS/Co(PO₃)₂@NC composite demonstrates a stable reversible capacity of 371.8 mAh g⁻¹ after 800 cycles at 1 A g⁻¹, and exhibits an excellent rate performance of 242.9 mAh g⁻¹ even at 8 A g⁻¹, alongside enhanced pseudocapacitive behavior. The assembled Co_1−xS/Co(PO₃)₂@NC//AC LIC delivers a high energy density of 90.47 Wh kg⁻¹ (at 26.28 W kg⁻¹), a high power density of 504.94 W kg⁻¹ (at 38.31 Wh kg⁻¹), and a remarkable cyclic stablitiy of 86.3% retention after 5000 cycles. This research is expected to provide valuable insights into the design of conversion-type electrode materials for future energy storage applications. Full article

Marine wave energy exhibits significant potential as a renewable resource due to its substantial energy storage capacity and high energy density. However, conventional wave power generation technologies often suffer from drawbacks such as high maintenance costs, cumbersome structures, and suboptimal conversion efficiencies, thereby limiting their potential. The wave power generation technologies based on micro-energy technology have emerged as promising new approaches in recent years, owing to their inherent advantages of cost-effectiveness, simplistic structure, and ease of manufacturing. This paper provides a comprehensive overview of the current research status in wave energy harvesting through micro-energy technologies, including detailed descriptions of piezoelectric nanogenerators, electromagnetic generators, triboelectric nanogenerators, dielectric elastomer generators, hydrovoltaic generators, and hybrid nanogenerators. Finally, we provide a comprehensive overview of the prevailing issues and challenges associated with these technologies, while also offering insights into the future development trajectory of wave energy harvesting technology. Full article

Concentrated photovoltaic (CPV) technology is based on the principle of concentrating direct sunlight onto small but very efficient photovoltaic (PV) cells. This approach allows the realization of PV modules with conversion efficiencies exceeding 30%, which is significantly higher than that of the flat panels. However, to achieve optimal performance, these modules must always be perpendicular to solar radiation; hence, they are mounted on high-precision solar trackers. This requirement has led to the predominant use of CPV technology in the construction of solar power plants in open and large fields for utility scale applications. In this paper, the authors present a novel approach allowing the use of this technology for residential installations, mounting the system both on flat and sloped roofs. Therefore, the main components of cell and primary lens have been chosen to contain the dimensions and, in particular, the thickness of the module. This paper describes the main design steps: thermal analysis allowed the housing construction material to be defined to contain cell working temperature, while with deep optical studies, experimentally validated main geometrical and functional characteristics of the CPV have been identified. The design of a whole CPV system includes thermal storage for domestic hot water and a 1 kWh electrical battery. The main design results indicate an estimated electrical conversion efficiency of 30%, based on a cell efficiency of approximately 42% under operational conditions and a measured optical efficiency of 74%. The CPV system has a nominal electric output of 550 Wp and can simultaneously generate 630 W of thermal power, resulting in an overall system efficiency of 65.5%. The system also boasts high optical acceptance angles (±0.6°) and broad assembly tolerances (±1 mm). Cost analysis reveals higher unit costs compared to conventional PV and CPV systems, but these become competitive when considering the benefit of excess thermal energy recovery and use by the end user. Full article

The research on boron/nitrogen (B/N)-based multiresonance thermally activated delayed fluorescence (MR-TADF) emitters has been a prominent topic due to their narrowband emission and high luminous efficiency. However, devices derived from the common types of narrowband TADF materials often experience an efficiency roll-off, which could be ascribed to their relatively slow triplet–singlet exciton interconversion. Since inserting the heavy Se atom into the B/N scheme has been a proven strategy to address the abovementioned issues, herein, extensive density functional theory (DFT) and time-dependent DFT (TD-DFT) simulations have been employed to explore the effects of the structural modification on a series of structurally modified selenium-doped derivatives. Furthermore, the two-layered ONIOM (QM/MM) model has been employed to study the pressure effects on the crystal structure and photophysical properties of the pristine CzBSe. The theoretical results found that the introduced tert-butyl units in Cz-BSeN could result in a shorter charge transfer distance and smaller reorganization energy than the parent CzBSe. In contrast to directly incorporating the o-carborane (Cb) unit to CzBSe, incorporating the bridged phenyl units is important in order to achieve narrowband emissions and high luminous efficiency. The lowest three triplet excited states of CzBSe, Cz-BSeN and PhCb-BSeN all contribute to their triplet–singlet exciton conversions, resulting in a high utilization of triplet excitons. The pressure has an evident influence on the photophysical properties of the aggregated CzBSe and is favored for obtaining narrowband emissions. Our work is promised to provide a feasible strategy for designing selenium-doped derivatives with narrowband emissions and rapid triplet–singlet exciton interconversions. Full article

This study investigates the factors influencing ${CO}_2$ emissions in Romania from 1990 to 2023 using the Autoregressive Distributed Lag (ARDL) model. Before the ARDL model, we identified a set of six policies that were ranked using Fuzzy Electre, Topsis, DEMATEL, and Vikor. The multi-criteria decision-making (MCDM) methods have highlighted the importance of a circular policy on ${CO}_2$ emission reduction, which should be a central focus for policymakers. The results of the ARDL model indicate that, in the long term, renewable energy production reduces ${CO}_2$ emissions, showing a negative relationship. Conversely, an increase in patent applications and urbanization contributes to higher ${CO}_2$ emissions, reflecting a positive impact. In total, five key factors were analyzed: ${CO}_2$ emissions per capita, patent applications, gross domestic product, share of energy production from renewables, and urbanization. Notably, GDP does not significantly explain ${CO}_2$ emissions in the long run, suggesting that economic growth alone is not a direct driver of ${CO}_2$ emission levels in Romania. This decoupling might result from improvements in energy efficiency, shifts towards less carbon-intensive industries, and the increased adoption of renewable energy sources. Romania has implemented effective environmental regulations and policies that mitigate the impact of economic growth on ${CO}_2$ emissions. Full article

In the context of energy conversion from renewable sources to distribution grids (insulated or not), a converter is often required to transfer energy from a low voltage source towards three-phase grids. This paper presents the HW design, the simulation results, and the conversion performance of a CSI converter intended to interface low-voltage renewable sources to three-phase grids. The main focus of this paper is to obtain the best performance in terms of voltage increase towards the output stage while maximizing the conversion efficiency. In comparison with the currently used energy conversion systems for small photovoltaic systems, hereafter some solutions were adopted to level and maximize the energy flow from the source to the DC-link and improve the quality of current supplied in terms of harmonic distortion. The proposed system is composed of two conversion stages: the first, voltage-to-current, the second current-to-current via a three-phase CSI bridge modulated with the SVM technique. The stages are not completely decoupled from an electrical point of view; therefore, in order to mitigate the effects of these interactions, synchronization strategies have been adopted. Full article

This article proposes the development of an optimal and robust control approach for the voltage regulation of a bi-directional DC-DC converter for its integration in battery energy storage and electric vehicle charging station applications. The objective of the proposed controller is to enhance the robustness and disturbance rejection capability of the bidirectional buck-boost converter. The inner current control loop adopts the optimal model predictive control (MPC) scheme while the outer voltage control loop has been developed utilizing the robust sliding mode control (SMC) approach. The results of the proposed robust & optimal control approach show better voltage conversion capabilities with improved transient response and steady-state characteristics in the presence of variations in load and disturbances. Full article

Corn straw is considered a renewable biomass energy source, and its unreasonable disposal leads to resource waste and environmental pollution. Black soldier fly (Hermetia illucens L.) larvae (BSFL) facilitate the bioconversion of various types of organic wastes. In this study, we found that 88% of BSFL survived, and 37.4% of corn straw was digested after 14 days of feeding with corn straw. Contrary to expectations, the pretreatment of corn straw with alkaline hydrogen peroxide did not promote its digestion but rather reduced the growth and survival rates of BSFL. Acinetobacter, Dysgonomonas, and unclassified Enterobacteriaceae were the abundant genera in the BSFL gut fed with corn straw. Compared with the standard diet, the relative abundances of carbohydrate metabolism genes, such as the gene abundances of β-glucosidase and α-glucosidase, were higher with corn straw as the substrate. These results suggested that the gut microbial community could regulate suitable and functional microorganisms in response to the substrates. Furthermore, four cellulase-producing strains, namely Klebsiella pneumoniae, Proteus mirabilis, Klebsiella oxytoca, and Providencia rettgeri, were isolated from the guts of corn straw BSFL. These four strains helped increase the conversion rates of corn straw, the weights of BSFL, and survival rates. In summary, we reared BSFL with corn straw and discovered the functions of gut microorganisms in adapting to the substrates. We also isolated four cellulase-producing strains from the BSFL guts and declared the benefits of BSFL digesting corn straw. Full article

Actuators based on moisture-sorption-responsive materials can convert moisture energy into mechanical/electrical energy, making the development of moisture-sorption materials a promising pathway for harnessing green energy to address the ongoing global energy crisis. The deformability of these materials plays a crucial role in the overall energy conversion performance, where moisture sorption capacity determines the energy density. Efforts to boost the moisture absorption capacity and rate have led to the development of a variety of moisture-responsive materials in recent years. These materials interact with water molecules in different manners and have shown diverse application scenarios. Here, in this review, we summarize the recent progress on moisture-sorption-responsive materials and their applications. We begin by categorizing moisture-sorption materials—biomaterials, polymers, nanomaterials, and crystalline materials—according to their interaction modes with water. We then review the correlation between moisture-sorption and energy harvesting performance. Afterwards, we provide examples of the typical applications using these moisture-sorption materials. Finally, we explore future research directions aimed at developing next-generation high-performance moisture-sorption materials with higher water uptake, tunable water affinity, and faster water absorption. Full article

This study investigates the multidimensional aspects of energy poverty in Pakistan from 2000 to 2022, specifically evaluating the direct, indirect, and total effects of socioeconomic and environmental factors. We employed Partial Least Squares Structural Equation Modeling (PLS-SEM) to examine the impacts of income, population, governance quality, energy intensity, fuel prices, and renewable energy consumption on energy poverty. The study further contributes by examining the mediating role of governance quality and developing the World Governance Indicators (WGI) Index. The findings indicate significant negative effects of energy intensity and renewable energy consumption on energy poverty. Conversely, population growth and income levels demonstrate positive effects, contradicting conventional economic development and energy access assumptions. Governance quality establishes direct and indirect effects that mediate most relationships between independent variables and energy poverty. Bootstrapping analysis confirms the significance of governance quality as a mediator. The model describes significant energy poverty variance with robust predictive relevance. This study emphasizes the need to adopt a comprehensive strategy to decrease Pakistan’s energy poverty by articulating socioeconomic, environmental, and governance factors. Our findings offer valuable information for policymakers to achieve UN Sustainable Development Goal 7, embarking on governance reforms, promoting sustainable growth, and enforcing investments in energy efficiency and renewable sources as Pakistan approaches the 2030 SDG 7 deadline. Full article

In this entry, the possibility of the implementation of a biorefinery based on multiple raw materials (from agricultural wastes, vegetable oils, etc.) is covered, pointing out the available technology to interconnect different processes so that the atom economy of the process is as high as possible, reducing the environmental impact and improving the efficiency of the energy or products obtained. For this purpose, this model is based on previous works published in the literature. The role of biorefineries is becoming more and more important in the current environmental scenario, as there is a global concern about different environmental issues such as climate change due to GHG emissions, among others. In this sense, a biorefinery presents several advantages such as the use of natural raw materials or wastes, with high atom economy values (that is, all the products are valorized and not released to the environment). As a consequence, the concept of a biorefinery perfectly fits with the Sustainable Development Goals, contributing to the sustainable growth of different regions or countries, regardless of their stage of development. The aim of this entry is the proposal of a biorefinery based on multiple raw materials, using different technologies such as transesterification to produce both biodiesel and biolubricants, steam reforming to produce hydrogen from glycerol or biogas, hydrothermal carbonization of sewage sludge to produce hydrochar, etc. As a result, these technologies have potential for the possible implementation of this biorefinery at the industrial scale, with high conversion and efficiency for most processes included in this biorefinery. However, there are some challenges like the requirement of the further technological development of certain processes. In conclusion, the proposed biorefinery offers a wide range of possibilities to enhance the production of energy and materials (hydrogen, biodiesel, biolubricants, different biofuels, hydrochar, etc.) through green technologies, being an alternative for petrol-based refineries. Full article

DC–DC converters are extensively utilized in renewable energy systems because of the flexibility in their output voltage and their good conversion efficiency. The design of an adaptive sliding mode controller is proposed in this paper for a buck converter system in the presence of load variations, power disturbances, and model uncertainties. The adaptive control law is designed based on the Lyapunov stability criterion and updated online according to variations in the load and external disturbances. The elimination of the chattering mechanism and robustness of the overall system is confirmed. Simulation results indicate better voltage regulation and disturbance rejection for the proposed adaptive controller as compared to the traditional control algorithms. Full article

The placenta is a vital organ in bovine reproduction, crucial for blood supply, nutrient transport, and embryonic development. It plays an essential role in the intrauterine growth of calves. However, the molecular mechanisms governing placental function in calves remain inadequately understood. Methods: We established transcriptome and proteome databases for low-birth-weight (LB) and high-birth-weight (HB) calf placentae, identifying key genes and proteins associated with birth weight through bioinformatics analyses that included functional enrichment and protein–protein interactions (PPIs). Both mRNA and protein levels were validated. Results: A total of 1494 differentially expressed genes (DEGs) and 294 differentially expressed proteins (DEPs) were identified when comparing the LB group to the HB group. Furthermore, we identified 53 genes and proteins exhibiting significant co-expression across both transcriptomic and proteomic datasets; among these, 40 were co-upregulated, 8 co-downregulated, while 5 displayed upregulation at the protein level despite downregulation at the mRNA level. Functional enrichment analyses (GO and KEGG) and protein–protein interaction (PPI) analysis indicate that, at the transcriptional level, the primary factor contributing to differences in calf birth weight is that the placenta of the high-birth-weight (HB) group provides more nutrients to the fetus, characterized by enhanced nutrient transport (SLC2A1 and SLC2A11), energy metabolism (ACSL1, MICALL2, PAG2, COL14A1, and ELOVL5), and lipid synthesis (ELOVL5 and ELOVL7). In contrast, the placenta of the low-birth-weight (LB) group prioritizes cell proliferation (PAK1 and ITGA3) and angiogenesis. At the protein level, while the placentae from the HB group exhibit efficient energy production and lipid synthesis, they also demonstrate reduced immunity to various diseases such as systemic lupus erythematosus and bacterial dysentery. Conversely, the LB group placentae excel in regulating critical biological processes, including cell migration, proliferation, differentiation, apoptosis, and signal transduction; they also display higher disease immunity markers (COL6A1, TNC CD36, CD81, Igh-1a, and IGHG) compared to those of the HB group placentae. Co-expression analysis further suggests that increases in calf birth weight can be attributed to both high-efficiency energy production and lipid synthesis within the HB group placentae (ELOVL5, ELOVL7, and ACSL1), alongside cholesterol biosynthesis and metabolic pathways involving CYP11A1 and CYP17A1. Conclusion: We propose that ELOVL5, ELOVL7, ACSL1, CYP11A1, and CYP17A1 serve as potential protein biomarkers for regulating calf birth weight through the modulation of the fatty acid metabolism, lipid synthesis, and cholesterol levels. Full article

As the Ethiopian energy demand urges for fuel options, it is essential to identify biomass fuels and estimate their energy potential. This study quantified the agricultural residues’ biomass resources and their energy potential. Further analyzed and characterized the potential nature through quantitative and qualitative methodologies with descriptive, comparative, explanatory, and exploratory studies. Five-year crop yield data of 27 crops were collected from the Central Statistical Agency of Ethiopia. Conversion factors into energy were surveyed from the literature. Subsequently, the residues available and their energy potentials were estimated. Mathematical and statistical analysis methods were considered in an Excel sheet. A new measure of natural potential capacity for energy was defined in two views (resource and application). Accordingly, their potential capacities were rated and prioritized comparatively. The gross energy potential of all the residues was estimated to be 494.7 PJ. With 30% collecting efficiency, it corresponds to the imported petroleum fuel in 2018. Five major crops contributed to 80% of this gross potential. Maize and sorghum presented the highest potential due to their superior yields and good natural potential capacities. They are also well distributed in all the regions. Cotton and maize’s natural potential capacities are the best in both views. Generally, commercial crops presented better capacities than the major cereal crops. However, major crops’ energy potentials dominated due to their yields. These resources need mobilization into modern and commercially accessible fuel forms that await intervention. Densified and carbonized forms of consumption in nearby industries and households are most viable for the Ethiopian case. Full article