Search Results (45)

The increasing importance of photovoltaic (PV) systems in the context of the energy transition, together with the need to improve their efficiency, has driven the adoption and development of intelligent and advanced maximum power point tracking (MPPT) techniques. Among these approaches, the Particle Swarm Optimization (PSO) algorithm stands out due to its simplicity, ease of implementation, low number of control parameters, robustness, and fast convergence capability, making it widely applied in modern MPPT systems. However, the performance of PSO in MPPT applications depends on the appropriate selection of both algorithm control parameters and implementation/configurations parameters. The control parameters include the cognitive (C₁) and social (C₂) learning factors, as well as the inertia factor (w), which directly influence swarm dynamics and the balance between exploration and exploitation mechanisms, that is, between global and local search. On the other hand, configuration parameters such as the number of particles and the initialization strategy affect the initial population diversity, the convergence speed toward the maximum power point, and the computational cost of the algorithm, defining the trade-off between speed and accuracy. Despite the extensive research in this field, there is still no clear consensus regarding the most suitable PSO parameter configuration for MPPT applications. This paper presents a statistical analysis of PSO parameter selection in MPPT applications, identifying the most frequently adopted parameter configurations and trends reported in the literature. The findings provide useful guidelines for researchers to select the PSO parameters according to different operating conditions, particularly under partial shading and irradiance variations. From a sustainability perspective, improving MPPT performance contributes to maximizing PV energy harvesting, reducing energy losses, and enhancing the reliability of PV systems, thereby supporting the transition toward more sustainable energy generation. Full article

Crop yield responses to reduced solar radiation are central to the design of agrivoltaic systems, yet crop-specific patterns and critical shading thresholds remain insufficiently characterized across diverse environments. This study evaluates yield responses across a global dataset of 546 observations from 66 studies, including agrivoltaic, shading, and agroforestry systems. Relative yield was analyzed in relation to reduction in solar radiation (RSR), crop type, and environmental variables using exploratory analysis, multiple linear regression, and tree-based ensemble models. Crop responses varied systematically across crop types. Fruits, berries, and fruity vegetables maintained or increased yield under lower shading levels, while forages, leafy vegetables, cereals, and tubers showed gradual declines, and maize and grain legumes exhibited the strongest sensitivity. Across models, yield responses were non-linear, with relatively stable yields at lower shading levels followed by accelerated declines beyond approximately 50–60% RSR. Climatic conditions further influenced these patterns, with crops in higher-radiation and warmer environments maintaining yields more effectively under partial shade. These findings demonstrate that crop yield responses depend on crop type, shading intensity, and environmental context, providing an agronomic basis for crop selection and agrivoltaic system design. Full article

Tree ferns are ubiquitous in New Zealand forests, but there is limited knowledge of their role in urban plant communities and potential use in restoration. We assessed sixteen sites by measuring 200 m² plots to investigate how tree ferns influence vascular plant composition in Hamilton, North Island, New Zealand. The sixteen plots were assigned to four site type combinations based on restoration status (restored or unrestored) and tree fern presence, each with four plots. Average native plant species richness was higher at sites with tree ferns (36 ± 16; S = 68) than at sites without (19 ± 14; S = 41), with more diverse ground fern and epiphyte assemblages. Higher native plant richness at restored sites (34 ± 18; S = 62) compared to unrestored sites (20 ± 14, S = 44) was partially attributed to increased plant abundances. Multivariate analyses revealed differences in plant community composition among our site types. Angiosperms and conifers were less prevalent in plots with tree ferns, suggesting competitive relationships among these groups. However, tree ferns were associated with some shade-tolerant trees, such as Schefflera digitata J.R.Forst. & G.Forst. Indicator species of sites with tree ferns were mainly ground ferns and epiphytes (e.g., Blechnum parrisiae Christenh. and Trichomanes venosum R.Br.), whereas species with high fidelity to sites without tree ferns were pioneer trees and shrubs (e.g., Pittosporum eugenioides A.Cunn.). Community structure analyses revealed that total basal areas were highest at unrestored sites with tree ferns, but restored sites exhibited more diverse tree communities. Environmental predictors that correlated significantly with the compositional differences among our site types were tree fern basal area and restoration age. Our results highlight the need to reconsider the potential of tree ferns in current restoration practice. Tree ferns were found to augment native plant diversity in our study, indicating their potential to enhance urban ecological restoration projects in New Zealand. Full article

As photovoltaic (PV) deployment has expanded from rural sites to the built environment, rooftops are increasingly used for electricity generation. In these settings, the visible sky is often partially obstructed by adjacent walls, producing shading that reduces energy yield. This study quantifies the effect of wall shading on incident solar radiation and system losses, and contrasts it with inter-row (mutual) shading experienced by PV arrays in open fields. Systems installed near obscuring walls are subject to both phenomena. To our knowledge, the specific impact of wall shading on PV systems has not been examined comprehensively. We characterize how wall height governs shadow geometry, determine the resulting numbers of shaded and unshaded cells and modules, and assess how shaded modules influence the performance of the remaining modules in a series string. For the parameter set analyzed, annual energy losses are 7.7% due to wall shading and 4% due to inter-row shading, yielding a combined loss of 10.2%. The methods and results provide a practical basis for designers to estimate shading losses and expected energy production for PV systems sited near obscuring walls. Full article

Although the upper nodal roots are vital for resource uptake in late-stage maize, their anatomical and physiological responses to varying nitrogen and light regimes remain unclear. In a field experiment, maize was grown under three nitrogen levels (0, 192, and 240 kg·ha⁻¹) and two light regimes (normal light and 50% shading). At flowering (R1), we selected the number, diameter, anatomy of nodal roots, root-bleeding sap composition, and grain yield. Sample sizes ranged from three to twelve replicates per treatment, depending on the trait measured. Data were analyzed using ANOVA and Duncan’s test (p < 0.05). Under normal light, N₁₉₂ and N₂₄₀ significantly enhanced stele and vessel diameters in the sixth and seventh nodal root whorls, vessel number and cortical cell layers in the fifth and seventh whorls, root-bleeding intensity, exudation rates of sucrose, abscisic acid, key free amino acids (Asn, Asp, Glu), and grain yield, compared to N₀. Shading markedly suppressed the nodal root anatomical structure, reducing root-bleeding intensity by 18.2–26.6% and yield by 30.6–40.8%; especially under SS-N0, which also notably increased the exudation of stress-related amino acids (particularly Asp and Glu). Correlation analysis revealed positive relationships of root-bleeding intensity with vessel area and grain yield, indicating that impaired root anatomy restricts resource transport under shading. Sufficient nitrogen partially alleviated these adverse effects. This study demonstrates that light and nitrogen synergistically regulate the upper nodal root anatomy, thereby modulating root-bleeding sap and ultimately influencing grain yield. These results provide a theoretical basis for high-yield maize cultivation and precision nitrogen management under low-light stress. Full article

A simple statistical model capturing the degree to which different patterns of urban development intensify urban heat islands (UHIs) and stress human health would be useful but has remained elusive. Accurately predicting street-level urban air temperatures from land cover and thermal data is difficult due to (1) the coarse scale of common remote sensing data, which do not observe the key environments beneath urban tree canopies, and, (2) conversely, the immense labor of intense, location-specific, ground-based survey campaigns. This work tested whether remotely sensed urban heat merged with land cover heterogeneity and shade/sun fractions, if combined at a sufficiently fine scale so as to be linearly additive, would enable simple and accurate statistical modeling of street-scale urban air temperatures with minimal empirical fitting. We used ground-based thermography of a sample of 12 residential streetscapes in Portland, Oregon, to characterize the land surface temperatures (LST_g) of eleven common urban surface cover types when sun-exposed and in shade. Surfaces were cooler in shade than sun, but with surface-specific differences not explained by greenery nor (im)perviousness. Also, surfaces on streetscapes with more canopy cover, even when sun-exposed at midday, remained significantly cooler than comparable sun-exposed surfaces on streets with less canopy cover, indicating the key significance of partial diurnal shading, not typically accounted for in urban thermal statistical models. We used high-resolution orthoimagery to quantify the area of each surface cover type within each streetscape and computed an area-weighted average surface temperature (T_s), accounting for sun/shade heterogeneity. The data revealed a significant, nearly 1:1 relationship between calculated T_s values and sun-shielded air temperatures (T_a). In contrast, relationships of T_a to tree coverage, impervious area, or the LST_g of dominant surface cover types were all statistically insignificant. These results suggest that statistical models may more reliably bridge the gap between remote sensing urban surface temperatures and reliable predictions of street-scale air temperatures if (1) analysis is at a sufficiently high resolution (e.g., <10 m) to avoid some of the known scale-dependence of urban thermal environments and enable simple weighted linear models, and (2) distinctions between thermal contributions of sunlit and shaded surfaces are included along with the influence of diurnal shading. Such models may provide effective and low-cost predictions of local UHIs and help inform effective street-level approaches to mitigating urban heat. Full article

Enclosed courtyards with partially ground floor pilotis represent a prevalent architectural spatial configuration in hot-humid regions, where the shaded outdoor areas serve as frequently utilized spaces for heat avoidance and rest. This study employed a combined approach of ENVI-met simulations and field measurements to investigate the wind and thermal environment in the shaded areas of courtyards under 40 different pilotis width configurations. The Comfortable Wind Zone Ratio (CWZR) and Physiological Equivalent Temperature (PET) were used as primary evaluation metrics to systematically investigate the influence of varying inlet/outlet width ratios in building pilotis on the wind-thermal environment within courtyard-shaded zones. The results demonstrate that: (1) Under a fixed outlet size, enlarging the inlet significantly enhances the CWZR in the shaded area, with a 28.66% difference observed between inlet sizes of L/4 and L. In contrast, under a fixed inlet size, expanding the outlet has a negligible effect on CWZR improvement. (2) Under a fixed outlet size, increasing the inlet width substantially reduces PET in the shaded zone, showing a 2.46 °C difference between inlet sizes of L/4 and L. Conversely, under a fixed inlet size, widening the outlet has a minimal impact on PET reduction. (3) A negative correlation exists between CWZR and PET in the shaded area, indicating that an increase in CWZR leads to a decrease in PET values. The findings provide bioclimatically quantified guidelines for the spatial design of courtyard pilotis in hot-humid regions, offering practical insights for optimizing thermal comfort in shaded outdoor environments. Full article

Partial shading is a common challenge influencing the performance of photovoltaic (PV) systems, particularly in urban and residential applications. A practical solution to mitigate hotspot formation due to shading is the use of bypass diodes. Increasing the number of bypass diodes further enhances PV system performance but alters the global maximum power points (MPPs), shifting their voltage locations and power magnitudes, consequently resulting in a change in the operating points in the efficiency curve of the inverters. This study investigates the impact of bypass diode numbers and inverter efficiency curves on PV system performance under various partial shading conditions. The analysis systematically deals with three inverters with different efficiency characteristics in terms of loading and input voltage, as well as module configurations with different numbers of bypass diodes. Additionally, three more factors—ambient temperature, inverter loading ratio by varying the number of series-connected PV modules, and shading intensity—are considered in the context of bypass diodes and inverter characteristics through the efficiency curve. The global MPPs of PV modules under different cases are simulated using a Simscape/Simulink-based circuit model with random irradiance samples. The results indicate the formation of bands according to the voltage that vary with bypass diode configurations. In this manner, utilizing the probabilities of these bands and inverter efficiency curves, the average PV system performance is determined for each case. The findings reveal the effects of the relationship between bypass diode configurations and inverter efficiency on PV system performance. As partial shading is especially common in dense urban areas, the results are of interest for the development of resilient and sustainable PV installations. Full article

Photovoltaic (PV) systems are increasingly recognized as a viable renewable energy source due to their clean, abundant, silent, and environmentally friendly nature. However, their efficiency is significantly influenced by environmental conditions, necessitating advanced control strategies to ensure optimal power extraction. This study aims to enhance the performance of PV systems by developing and evaluating maximum power point tracking (MPPT) algorithms capable of operating effectively under both uniform irradiance and partial shading conditions (PSCs). Specifically, two metaheuristic algorithms—Particle Swarm Optimization (PSO) and Cuckoo Search Optimization (CSO)—are modeled, implemented, and tested for tracking the global peak power (GPP) in various static and dynamic scenarios. Simulation results indicate that both algorithms accurately and efficiently track the GPP under static uniform and PSCs. Under dynamic conditions, while both the PSO and CSO can initially locate the GPP, they fail to maintain accurate tracking during subsequent intervals. Notably, CSO exhibits reduced oscillations and faster response time compared with PSO. These findings suggest that while metaheuristic MPPT methods are effective in static environments, their performance in dynamic conditions remains a challenge requiring further enhancement. Full article

Solar radiation is crucial for intercropping, while partial shading can protect intercropped soybean leaves from irradiation damage during the pod-ripening period under high solar radiation. This study explored the leaf dynamics and soybean quality for the maize–soybean system, for monoculture soybean (MS), monoculture maize (MM), two-row maize + three-row soybean (IS2-3), and four-row maize + four-row soybean (IS4-4). The results revealed that soybean leaves under IS2-3 and IS4-4 treatments showed increases in Rubisco activity of 59.8% and 12.4% compared with MS, respectively. The antioxidant capacity in soybean leaves in MS was higher than that under intercropping treatments. Soybean leaves under IS2-3 and IS4-4 exhibited higher alpha and beta diversities in their endophytes compared with MS. The relative abundance of pathotrophs under IS2-3 was reduced by 19.1% and 22.6% compared to that of those under MS and IS4-4, respectively. The total land equivalent ratio (LER) under IS2-3 was more than 1.00, and increased by 6.4% and 15.7% compared with IS4-4 in 2023 and 2024, respectively. Soybean seeds under IS2-3 and IS4-4 showed 4.1% and 4.2% increases in crude protein content compared to those of MS, respectively. Among various biosynthesis and metabolism processes, flavone and flavonol biosynthesis exerted a stronger influence on soybean seeds in MS, IS2-3, and IS4-4. Soybean seeds under IS2-3 showed elevated genistein content and reduced daidzein content compared with those of MS. Intercropping soybean treatments, especially IS2-3, maintained leaf health during the pod-ripening period and enhanced the crude protein content compared with sole soybean treatment, thus guiding the design of intercropping in areas with high solar radiation. Full article

The powder obtained from rosehip waste can be used as an ingredient in meat products because it contains polyphenolic compounds with preservative and antioxidant effects and carotenoid compounds with a colouring effect. This study aimed to evaluate how partially replacing raw meat with this powder impacts the quality of pork sausages. Therefore, three sausage formulations (PSc-control pork sausages; PS2.7%rp-pork sausages with 2.7% powder from rosehip waste; PS5.5%rp-pork sausages with 5.5% powder from rosehip waste) were prepared and evaluated during storage from physicochemical, colour, texture, and sensory points of view, as well as for their polyphenol and carotenoid contents. The use of the powder from rosehip waste as an ingredient in pork sausages resulted in a significant decrease in moisture and protein content but an increase in total carbohydrates, polyphenols, and carotenoids; additionally, it significantly decreased the pH and easily hydrolysable nitrogen content of sausages, thus demonstrating a preservative effect. It also positively influenced their colour (by intensifying the shades of red and yellow), as well as the sausages’ gumminess and chewiness (by reducing them). Although it slightly affected their taste and texture, the consumer acceptance rate for reformulated sausages was reasonable. In conclusion, the powder obtained from rosehip waste is a promising functional ingredient in pork sausage reformulation. Full article

Under uniform operating conditions, the power–voltage (P-V) and current–voltage (I-V) curves of a photovoltaic (PV) system have only one maximum point, which facilitates the operation of maximum power point tracking (MPPT) algorithms. In practice, the PV systems often operate under heterogeneous environments due to partial shading conditions (PSCs). The P-V and I-V curves exhibit multiple extremes, and distinguishing between the global maximum power point (GMPP) and local maximum power point (LMPP) is a major challenge for algorithms aiming to improve performance and convergence speed. This paper presents a global maximum power point tracking (GMPPT) method based on simulating the behavior of the I-V curve of a PV system under the influence of PSCs. With only one initial parameter selected, the proposed solution quickly determines the LMPPs based on the characteristics of the PV type and the shading condition during operation. This work helps to limit the potential GMPP region to reduce the search time and improve efficiency by using a simple algorithm and a small tuning step size. The experimental results demonstrate that the proposed method provides superior MPPT performance and significantly reduces search time due to improved GMPP detection accuracy combined with small step sizes. Full article

This study aimed to identify the key environmental factors influencing the survival and growth of the endangered plant Lychnis kiusiana Makino through translocation experiments across different sites (sites A, B, C; A = shady, B = partial shady, C = sunny). The analysis revealed strong correlations between survival and growth with factors such as soil moisture, soil electroconductivity, coverage, and light. Utilizing a multimodel inference approach, which accounts for complex interactions among environmental variables, the study found that coverage and soil electroconductivity were the most significant predictors of survival, while soil moisture was the primary factor affecting growth. Coverage played a crucial role in early survival by regulating the microclimate, providing shading effects, and aiding in soil moisture retention. Soil electroconductivity, an indicator of nutrient availability, was positively associated with higher survival rates, suggesting the importance of nutrient-rich environments for the establishment of Lychnis kiusiana. Soil moisture was identified as a vital element for the survival and growth of wetland plants, especially during the initial translocation phase when a stable water supply is essential. Despite the study’s focus on a single, restricted habitat with a small population size, it effectively identified the key factors driving survival and growth under varying environmental conditions. These findings offer valuable insights for understanding the habitat requirements of Lychnis kiusiana and provide fundamental data for the conservation and restoration of similar endangered species. The results of this study emphasize the need to strengthen restoration strategies through long-term monitoring, genetic analysis, and broader translocation experiments, and to develop sustainable conservation approaches. Ultimately, this research makes a significant contribution to the sustainable conservation of endangered plants and supports efforts for ecosystem restoration and biodiversity enhancement, aligning with scientific objectives of sustainable environmental management and biodiversity conservation Full article

Global reliance on depleting energy resources is driving the urgent need for alternative solutions to address escalating energy demands. Solar energy, a prominent renewable resource, leverages various configurations and techniques to maximize power output, even under challenging environmental conditions. In photovoltaic (PV) arrays, partial shading conditions (PSCs) significantly hinder efficiency by reducing power extraction across solar panels. Traditionally, configurations such as series, parallel, series-to-parallel, and bridge-linked (BL) are employed to optimize power output; however, each has limitations under PSCs. Here, we introduce a modified bridge-linked (Modified BL) configuration designed to mitigate the adverse effects of partial shading on PV arrays. This approach allows for interconnected solar modules that reduce shading impact across an entire array, thus preserving efficiency by isolating shaded sections and minimizing power loss. The Modified BL configuration not only supports maximum power point tracking (MPPT) but also enhances resilience against shading, ensuring stable power output. Our simulation results underscore the critical influence of irradiance levels on PV electricity generation, suggesting that incorporating irradiance variability as a design parameter is essential in selecting optimal PV interconnection schemes under PSCs. This study contributes to advancing solar array design by providing a robust method to maintain power output in partial shading conditions, ultimately supporting broader efforts in renewable energy optimization. Full article

The article considers the problem of an influence of partial shading on the characteristics of photovoltaic modules (PV modules). Different manners of connections of silicon solar cells contained in such modules are considered, e.g., classical PV modules (I and II generation of modules) and modules made using half-cut technology (III generation of modules). A model of PV modules was proposed. This model has the form of a network for the SPICE program and takes into account the influence of partial shading of the PV module caused by clouds or terrain and architectural obstacles on its current and voltage. The form of the model was described, and the DC characteristics of the considered classical and half-cut modules, calculated using the formulated model, were compared to the measurement results under different shading conditions. Some calculations using the proposed model were performed for different methods to connect solar cells in PV modules. The obtained results were discussed. Full article