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Search Results (1,722)

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26 pages, 4081 KiB  
Article
Melatonin-Induced Modulation of Polyphenols and Glycolytic Pathways in Relation to Postharvest Quality of Blue Honeysuckle Fruits
by Jinli Qiao, Liangchuan Guo, Zhen Xiao, Junwei Huo, Xiaonan Sui, Fang Gao and Yan Zhang
Foods 2025, 14(15), 2646; https://doi.org/10.3390/foods14152646 - 28 Jul 2025
Abstract
The impact of exogenous melatonin treatment on the postharvest quality and storability of blue honeysuckle fruit was investigated. Fruits were immersed in melatonin solutions at concentrations of 0 (control), 0.01, 0.05, and 0.25 mM for 5 min and subsequently stored at –1 °C [...] Read more.
The impact of exogenous melatonin treatment on the postharvest quality and storability of blue honeysuckle fruit was investigated. Fruits were immersed in melatonin solutions at concentrations of 0 (control), 0.01, 0.05, and 0.25 mM for 5 min and subsequently stored at –1 °C for 63 d. Among all treatments, the combination of two-week storage without fruit puncturing and 0.05 mM melatonin application significantly delayed fruit softening and decay even at the initial stage of storage, while also increasing the concentration of phenolic compounds and enhancing antioxidant activity. During the later storage period (28–63 d), melatonin-treated fruits maintained higher levels of maltose, fructose, and sucrose, contributing to improved flavor retention. In contrast, both lower (0.01 mM) and higher (0.25 mM) concentrations were less effective or even detrimental to fruit quality. HPLC-ESI-QTOF-MS2 analysis revealed that 0.05 mM melatonin effectively preserved several functional phenolics, including p-coumaroylquinic acid, caffeoyl glucose, 5-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, luteolin-7-O-glucoside, and hydroxytyrosol. Thus, 0.05 mM melatonin is effective in delaying senescence and maintaining the postharvest quality of blue honeysuckle fruit. Full article
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26 pages, 5113 KiB  
Article
Eco-Friendly Sandwich Panels for Energy-Efficient Façades
by Susana P. B. Sousa, Helena C. Teixeira, Giorgia Autretto, Valeria Villamil Cárdenas, Stefano Fantucci, Fabio Favoino, Pamela Voigt, Mario Stelzmann, Robert Böhm, Gabriel Beltrán, Nicolás Escribano, Belén Hernández-Gascón, Matthias Tietze and Andreia Araújo
Sustainability 2025, 17(15), 6848; https://doi.org/10.3390/su17156848 - 28 Jul 2025
Abstract
To meet the European Green Deal targets, the construction sector must improve building thermal performance via advanced insulation systems. Eco-friendly sandwich panels offer a promising solution. Therefore, this work aims to develop and validate a new eco-friendly composite sandwich panel (basalt fibres and [...] Read more.
To meet the European Green Deal targets, the construction sector must improve building thermal performance via advanced insulation systems. Eco-friendly sandwich panels offer a promising solution. Therefore, this work aims to develop and validate a new eco-friendly composite sandwich panel (basalt fibres and recycled extruded polystyrene) with enhanced multifunctionality for lightweight and energy-efficient building façades. Two panels were produced via vacuum infusion—a reference panel and a multifunctional panel incorporating phase change materials (PCMs) and silica aerogels (AGs). Their performance was evaluated through lab-based thermal and acoustic tests, numerical simulations, and on-site monitoring in a living laboratory. The test results from all methods were consistent. The PCM-AG panel showed 16% lower periodic thermal transmittance (0.16 W/(m2K) vs. 0.19 W/(m2K)) and a 92% longer time shift (4.26 h vs. 2.22 h), indicating improved thermal inertia. It also achieved a single-number sound insulation rating of 38 dB. These findings confirm the panel’s potential to reduce operational energy demand and support long-term climate goals. Full article
9 pages, 275 KiB  
Article
The Effect of Different Intraperitoneal Hyperthermic Chemotherapy (HIPEC) Regimens on Serum Electrolyte Levels: A Comparison of Oxaliplatin and Mitomycin C
by Vural Argın, Mehmet Ömer Özduman, Ahmet Orhan Sunar, Mürşit Dinçer, Aziz Serkan Senger, Selçuk Gülmez, Orhan Uzun, Mustafa Duman and Erdal Polat
Medicina 2025, 61(8), 1345; https://doi.org/10.3390/medicina61081345 - 25 Jul 2025
Viewed by 129
Abstract
Background and Objectives: This study aimed to compare the effects of HIPEC procedures using oxaliplatin and mitomycin C on serum electrolyte, glucose, and lactate levels, with a specific focus on the carrier solutions employed. Materials and Methods: A retrospective analysis was [...] Read more.
Background and Objectives: This study aimed to compare the effects of HIPEC procedures using oxaliplatin and mitomycin C on serum electrolyte, glucose, and lactate levels, with a specific focus on the carrier solutions employed. Materials and Methods: A retrospective analysis was performed on 82 patients who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal peritoneal metastases. Patients were assigned to one of two groups based on the chemotherapeutic agent used: oxaliplatin (n = 63) or mitomycin C (MMC, n = 19). The oxaliplatin group was further subdivided based on the carrier solution used: 5% dextrose (D5W, n = 29) or peritoneal dialysate (n = 34). The assignment of regimens was based on institutional protocols and surgeon preference. Pre- and post-HIPEC serum levels of sodium, potassium, bicarbonate, glucose, and lactate were compared. Results: Significant biochemical changes were observed across groups, depending on both the chemotherapeutic agent and carrier solution. In the MMC group (peritoneal dialysate), only lactate increased significantly post-HIPEC (p = 0.001). In the oxaliplatin–peritoneal dialysate group, significant changes were observed in bicarbonate (p = 0.009), glucose (p = 0.001), and lactate (p < 0.001), whereas sodium and potassium remained stable. The oxaliplatin–D5W group showed significant changes in all parameters: sodium (p = 0.001), potassium (p = 0.001), bicarbonate (p = 0.001), glucose (p < 0.001), and lactate (2.4 → 7.6 mmol/L, p < 0.001). Between-group comparisons revealed significant differences in sodium, potassium, glucose, and lactate changes (p < 0.05), but not in bicarbonate (p = 0.099). Demographic and clinical characteristics—including age, sex, primary disease, ICU stay, and 90-day mortality were similar across groups. Conclusions: The use of dextrose-containing solutions with oxaliplatin was associated with marked metabolic disturbances, including clinically meaningful hyponatremia, hypokalemia, and hyperglycemia in the early postoperative period. These findings suggest that the choice of carrier solution is as important as the chemotherapeutic agent in terms of perioperative safety. Closer postoperative electrolyte monitoring is recommended when using dextrose-based regimens. The retrospective design and sample size imbalance between groups are acknowledged limitations. Nonetheless, this study offers clinically relevant insights and lays the groundwork for future prospective research. Full article
(This article belongs to the Special Issue Advances in Colorectal Surgery and Oncology)
16 pages, 2322 KiB  
Article
Reducing Marine Ecotoxicity and Carbon Burden: A Life Cycle Assessment Study of Antifouling Systems
by Trent Kelly, Emily M. Hunt, Changxue Xu and George Tan
Processes 2025, 13(8), 2356; https://doi.org/10.3390/pr13082356 - 24 Jul 2025
Viewed by 193
Abstract
Marine biofouling significantly impacts the performance and longevity of polymer-based marine structures, particularly those designed for hydrodynamic applications such as Vortex-Induced Vibration suppression systems. Traditional antifouling solutions rely on copper-based multilayer coatings, which present challenges including mechanical vulnerability (e.g., chipping and scratching), high [...] Read more.
Marine biofouling significantly impacts the performance and longevity of polymer-based marine structures, particularly those designed for hydrodynamic applications such as Vortex-Induced Vibration suppression systems. Traditional antifouling solutions rely on copper-based multilayer coatings, which present challenges including mechanical vulnerability (e.g., chipping and scratching), high material and labor demands, and environmental concerns such as volatile organic compound emissions and copper leaching. Recent developments in material science have introduced an alternative system involving the direct incorporation of copper oxide (Cu2O) into high-density polyethylene (HDPE) during the molding process. This study conducts a comparative life cycle assessment (LCA) of two antifouling integration methods—System 1 (traditional coating-based) and System 2 (Cu2O-impregnated HDPE)—evaluating their environmental impact across production, application, use, and end-of-life stages. The functional unit used for this study was 1 square meter for a time period of five years. Using ISO 14040-compliant methodology and data from Ecoinvent and OpenLCA, three impact categories were assessed: global warming potential (GWP), cumulative energy demand (CED), and marine aquatic ecotoxicity Potential (MAETP). The results indicate that System 2 outperforms System 1 in GWP (4.42 vs. 5.65 kg CO2-eq), CED (75.3 vs. 91.0 MJ-eq), and MAETP (327,002 vs. 469,929 kg 1,4-DCB-eq) per functional unit over a five-year lifespan, indicating a 21.8%, 17.3%, and 30.4% reduction in the key impact factors, respectively. These results suggest that direct Cu2O incorporation offers a more environmentally sustainable and mechanically resilient antifouling strategy, supporting the potential of embedded antifouling systems to shift industry practices toward more sustainable marine infrastructure. Full article
(This article belongs to the Special Issue Circular Economy on Production Processes and Systems Engineering)
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18 pages, 2592 KiB  
Article
A Minimal Solution for Binocular Camera Relative Pose Estimation Based on the Gravity Prior
by Dezhong Chen, Kang Yan, Hongping Zhang and Zhenbao Yu
Remote Sens. 2025, 17(15), 2560; https://doi.org/10.3390/rs17152560 - 23 Jul 2025
Viewed by 125
Abstract
High-precision positioning is the foundation for the functionality of various intelligent agents. In complex environments, such as urban canyons, relative pose estimation using cameras is a crucial step in high-precision positioning. To take advantage of the ability of an inertial measurement unit (IMU) [...] Read more.
High-precision positioning is the foundation for the functionality of various intelligent agents. In complex environments, such as urban canyons, relative pose estimation using cameras is a crucial step in high-precision positioning. To take advantage of the ability of an inertial measurement unit (IMU) to provide relatively accurate gravity prior information over a short period, we propose a minimal solution method for the relative pose estimation of a stereo camera system assisted by the IMU. We rigidly connect the IMU to the camera system and use it to obtain the rotation matrices in the roll and pitch directions for the entire system, thereby reducing the minimum number of corresponding points required for relative pose estimation. In contrast to classic pose-estimation algorithms, our method can also calculate the camera focal length, which greatly expands its applicability. We constructed a simulated dataset and used it to compare and analyze the numerical stability of the proposed method and the impact of different levels of noise on algorithm performance. We also collected real-scene data using a drone and validated the proposed algorithm. The results on real data reveal that our method exhibits smaller errors in calculating the relative pose of the camera system compared with two classic reference algorithms. It achieves higher precision and stability and can provide a comparatively accurate camera focal length. Full article
(This article belongs to the Section Urban Remote Sensing)
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25 pages, 760 KiB  
Article
Scheduling the Exchange of Context Information for Time-Triggered Adaptive Systems
by Daniel Onwuchekwa, Omar Hekal and Roman Obermaisser
Algorithms 2025, 18(8), 456; https://doi.org/10.3390/a18080456 - 22 Jul 2025
Viewed by 105
Abstract
This paper presents a novel metascheduling algorithm to enhance communication efficiency in off-chip time-triggered multi-processor system-on-chip (MPSoC) platforms, particularly for safety-critical applications in aerospace and automotive domains. Time-triggered communication standards such as time-sensitive networking (TSN) and TTEthernet effectively enable deterministic and reliable communication [...] Read more.
This paper presents a novel metascheduling algorithm to enhance communication efficiency in off-chip time-triggered multi-processor system-on-chip (MPSoC) platforms, particularly for safety-critical applications in aerospace and automotive domains. Time-triggered communication standards such as time-sensitive networking (TSN) and TTEthernet effectively enable deterministic and reliable communication across distributed systems, including MPSoC-based platforms connected via Ethernet. However, their dependence on static resource allocation limits adaptability under dynamic operating conditions. To address this challenge, we propose an offline metascheduling framework that generates multiple precomputed schedules corresponding to different context events. The proposed algorithm introduces a selective communication strategy that synchronizes context information exchange with key decision points, thereby minimizing unnecessary communication while maintaining global consistency and system determinism. By leveraging knowledge of context event patterns, our method facilitates coordinated schedule transitions and significantly reduces communication overhead. Experimental results show that our approach outperforms conventional scheduling techniques, achieving a communication overhead reduction ranging from 9.89 to 32.98 times compared to a two-time-unit periodic sampling strategy. This work provides a practical and certifiable solution for introducing adaptability into Ethernet-based time-triggered MPSoC systems without compromising the predictability essential for safety certification. Full article
(This article belongs to the Special Issue Bio-Inspired Algorithms: 2nd Edition)
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24 pages, 3714 KiB  
Article
DTCMMA: Efficient Wind-Power Forecasting Based on Dimensional Transformation Combined with Multidimensional and Multiscale Convolutional Attention Mechanism
by Wenhan Song, Enguang Zuo, Junyu Zhu, Chen Chen, Cheng Chen, Ziwei Yan and Xiaoyi Lv
Sensors 2025, 25(15), 4530; https://doi.org/10.3390/s25154530 - 22 Jul 2025
Viewed by 214
Abstract
With the growing global demand for clean energy, the accuracy of wind-power forecasting plays a vital role in ensuring the stable operation of power systems. However, wind-power generation is significantly influenced by meteorological conditions and is characterized by high uncertainty and multiscale fluctuations. [...] Read more.
With the growing global demand for clean energy, the accuracy of wind-power forecasting plays a vital role in ensuring the stable operation of power systems. However, wind-power generation is significantly influenced by meteorological conditions and is characterized by high uncertainty and multiscale fluctuations. Traditional recurrent neural network (RNN) and long short-term memory (LSTM) models, although capable of handling sequential data, struggle with modeling long-term temporal dependencies due to the vanishing gradient problem; thus, they are now rarely used. Recently, Transformer models have made notable progress in sequence modeling compared to RNNs and LSTM models. Nevertheless, when dealing with long wind-power sequences, their quadratic computational complexity (O(L2)) leads to low efficiency, and their global attention mechanism often fails to capture local periodic features accurately, tending to overemphasize redundant information while overlooking key temporal patterns. To address these challenges, this paper proposes a wind-power forecasting method based on dimension-transformed collaborative multidimensional multiscale attention (DTCMMA). This method first employs fast Fourier transform (FFT) to automatically identify the main periodic components in wind-power data, reconstructing the one-dimensional time series as a two-dimensional spatiotemporal representation, thereby explicitly encoding periodic features. Based on this, a collaborative multidimensional multiscale attention (CMMA) mechanism is designed, which hierarchically integrates channel, spatial, and pixel attention to adaptively capture complex spatiotemporal dependencies. Considering the geometric characteristics of the reconstructed data, asymmetric convolution kernels are adopted to enhance feature extraction efficiency. Experiments on multiple wind-farm datasets and energy-related datasets demonstrate that DTCMMA outperforms mainstream methods such as Transformer, iTransformer, and TimeMixer in long-sequence forecasting tasks, achieving improvements in MSE performance by 34.22%, 2.57%, and 0.51%, respectively. The model’s training speed also surpasses that of the fastest baseline by 300%, significantly improving both prediction accuracy and computational efficiency. This provides an efficient and accurate solution for wind-power forecasting and contributes to the further development and application of wind energy in the global energy mix. Full article
(This article belongs to the Section Intelligent Sensors)
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23 pages, 406 KiB  
Article
Periodically Kicked Rotator with Power-Law Memory: Exact Solution and Discrete Maps
by Vasily E. Tarasov
Fractal Fract. 2025, 9(7), 472; https://doi.org/10.3390/fractalfract9070472 - 21 Jul 2025
Viewed by 315
Abstract
This article discusses the transformation of a continuous-time model of the fractional system into a discrete-time model of the fractional system. For the continuous-time model, the exact solution of the nonlinear equation with fractional derivatives (FDs) that has the form of the damped [...] Read more.
This article discusses the transformation of a continuous-time model of the fractional system into a discrete-time model of the fractional system. For the continuous-time model, the exact solution of the nonlinear equation with fractional derivatives (FDs) that has the form of the damped rotator type with power non-locality in time is obtained.This equation with two FDs and periodic kicks is solved in the general case for the arbitrary orders of FDs without any approximations. A three-stage method for solving a nonlinear equation with two FDs and deriving discrete maps with memory (DMMs) is proposed. The exact solutions of the nonlinear equation with two FDs are obtained for arbitrary values of the orders of these derivatives. In this article, the orders of two FDs are not related to each other, unlike in previous works. The exact solution of nonlinear equation with two FDs of different orders and periodic kicks are proposed. Using this exact solution, we derive DMMs that describe a kicked damped rotator with power-law non-localities in time. For the discrete-time model, these damped DMMs are described by the exact solution of nonlinear equations with FDs at discrete time points as the functions of all past discrete moments of time. An example of the application, the exact solution and DMMs are proposed for the economic growth model with two-parameter power-law memory and price kicks. It should be emphasized that the manuscript proposes exact analytical solutions to nonlinear equations with FDs, which are derived without any approximations. Therefore, it does not require any numerical proofs, justifications, or numerical validation. The proposed method gives exact analytical solutions, where approximations are not used at all. Full article
22 pages, 3128 KiB  
Article
Initial Values Determination of Thrust Parameters for Continuously Low-Thrust Maneuvering Spacecraft
by Wen Guo, Xuefeng Tao, Min Hu and Wen Xue
Appl. Sci. 2025, 15(14), 8064; https://doi.org/10.3390/app15148064 - 20 Jul 2025
Viewed by 207
Abstract
Continuous low thrust is widely used in orbit transfer maneuvers. If the unknown maneuvers are not correctly compensated, the orbiting accuracy will be seriously affected. We propose a rapid method for pre-identifying thrust acceleration based on single-arc orbit determination in order to determine [...] Read more.
Continuous low thrust is widely used in orbit transfer maneuvers. If the unknown maneuvers are not correctly compensated, the orbiting accuracy will be seriously affected. We propose a rapid method for pre-identifying thrust acceleration based on single-arc orbit determination in order to determine the orbit of non-cooperative continuous low-thrust maneuvering spacecraft. The single-arc orbit determination results of two ground-based radar observations with a certain time interval are used to inversely determine the direction and magnitude of acceleration of the spacecraft under continuous thrust based on their relationship with satellite orbit parameters. The solution error is relatively small when using this method, even over a short period of time when data are sparse. The results can then be applied to the orbital adjustment of a satellite. The results show that when the satellite climbs with maximum tangential acceleration, the interval between the two radar observations is greater than 7 h, and the proposed method can rapidly pre-identify tangential thrust acceleration with a solution error of less than 5%. When the satellite adjusts the orbital plane with the maximum normal acceleration, the average relative measurement error of the normal acceleration is about 20% when the time interval between two observations is 24 h. The longer the observation interval and the greater the thrust acceleration, the smaller the relative error. The calculation results can be used as the initial value for precision orbit determination of continuous low-thrust maneuvering spacecraft. Full article
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29 pages, 1493 KiB  
Article
Effects of Hydroponic Cultivation on Baby Plant Characteristics of Tetragonia tetragonioides (Pallas) O. Kunze at Harvest and During Storage as Minimally Processed Produce
by Alessandro Esposito, Alessandra Moncada, Filippo Vetrano, Eristanna Palazzolo, Caterina Lucia and Alessandro Miceli
Horticulturae 2025, 11(7), 846; https://doi.org/10.3390/horticulturae11070846 - 17 Jul 2025
Viewed by 244
Abstract
Tetragonia tetragonioides, or New Zealand spinach, is a widespread halophyte native to eastern Asia, Australia, and New Zealand, and naturalized in some Mediterranean regions. This underutilized vegetable is consumed for its leaves, raw or cooked. For the first time, we investigated the [...] Read more.
Tetragonia tetragonioides, or New Zealand spinach, is a widespread halophyte native to eastern Asia, Australia, and New Zealand, and naturalized in some Mediterranean regions. This underutilized vegetable is consumed for its leaves, raw or cooked. For the first time, we investigated the feasibility of using whole baby plants (including stems and leaves) as raw material for ready-to-eat (RTE) vegetable production. Our study assessed Tetragonia’s suitability for hydroponic cultivation over two cycles (autumn–winter and spring). We investigated the impact of increasing nutrient rates (only water, half-strength, and full-strength nutrient solutions) and plant densities (365, 497, and 615 plants m−2 in the first trial and 615 and 947 plants m−2 in the second) on baby plant production. We also analyzed the plants’ morphological and biochemical characteristics, and their viability for cold storage (21 days at 4 °C) as a minimally processed product. Tetragonia adapted well to hydroponic cultivation across both growing periods. Nevertheless, climatic conditions, plant density, and nutrient supply significantly influenced plant growth, yield, nutritional quality, and post-harvest storage. The highest plant density combined with the full-strength nutrient solution resulted in the highest yield, especially during spring (1.8 kg m−2), and favorable nutritional characteristics (β-carotene, Vitamin C, Fe, Cu, Mn, and Zn). Furthermore, Tetragonia baby plants proved suitable for minimal processing, maintaining good quality retention for a minimum of 14 days, thus resulting in a viable option for the RTE vegetable market. Full article
(This article belongs to the Section Protected Culture)
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18 pages, 2823 KiB  
Article
Quasi-Periodic Dynamics and Wave Solutions of the Ivancevic Option Pricing Model Using Multi-Solution Techniques
by Sadia Yasin, Fehaid Salem Alshammari, Asif Khan and Beenish
Symmetry 2025, 17(7), 1137; https://doi.org/10.3390/sym17071137 - 16 Jul 2025
Viewed by 179
Abstract
In this research paper, we study symmetry groups, soliton solutions, and the dynamical behavior of the Ivancevic Option Pricing Model (IOPM). First, we find the Lie symmetries of the considered model; next, we use them to determine the corresponding symmetry groups. Then, we [...] Read more.
In this research paper, we study symmetry groups, soliton solutions, and the dynamical behavior of the Ivancevic Option Pricing Model (IOPM). First, we find the Lie symmetries of the considered model; next, we use them to determine the corresponding symmetry groups. Then, we attempt to solve IOPM by means of two methods. We provide some wave solutions and give further details of the solution using 2D and 3D graphs. These results are interpreted as important clarifications in financial mathematics and deepen our understanding of the dynamics involved during the pricing of options. Secondly, the quasi-periodic behavior of the two-dimensional dynamical system and its perturbed system are plotted using Python software (Python 3.13.5 version). Various frequencies and amplitudes are considered to confirm the quasi-periodic behavior via the Lyapunov exponent, bifurcation diagram, and multistability analysis. These findings are particularly in consonance with current research that investigates IOPM as a nonlinear wave alternate for normal models and the importance of graphical representations in the understanding of financial derivative dynamics. We, therefore, hope to fill in the gaps in the literature that currently exist about the use of multi-solution methods and their effects on financial modeling through the employment of sophisticated graphical techniques. This will be helpful in discussing matters in the field of financial mathematics and open up new directions of investigation. Full article
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26 pages, 686 KiB  
Article
Galerkin’s Spectral Method in the Analysis of Antenna Wall Operation
by Marian Wnuk
Appl. Sci. 2025, 15(14), 7901; https://doi.org/10.3390/app15147901 - 15 Jul 2025
Viewed by 150
Abstract
In this paper, a solution to the problem of electromagnetic field scattering on a periodic, constrained, planar antenna structure placed on the boundary of two dielectric media was formulated. The scattering matrix of such a structure was derived, and its generalization for the [...] Read more.
In this paper, a solution to the problem of electromagnetic field scattering on a periodic, constrained, planar antenna structure placed on the boundary of two dielectric media was formulated. The scattering matrix of such a structure was derived, and its generalization for the case of an antenna with a multilayer dielectric substrate was defined. By applying the Galerkin spectral method, the problem was reduced to a system of algebraic equations for the coefficients of current distribution on metal elements of the antenna grid, considering the distribution of the electromagnetic field on Floquet harmonics. The finite transverse dimension of the antenna was considered by introducing, to the solution of the case of an unconstrained antenna, a window function on the antenna aperture. The presented formalism allows modeling the operation of periodic, dielectric, composite antenna arrays. Full article
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13 pages, 3867 KiB  
Article
Effect of Hot Isostatic Pressing on Mechanical Properties of K417G Nickel-Based Superalloy
by Fan Wang, Yuandong Wei, Yi Zhou, Wenqi Guo, Zexu Yang, Jinghui Jia, Shusuo Li and Haigen Zhao
Crystals 2025, 15(7), 643; https://doi.org/10.3390/cryst15070643 - 11 Jul 2025
Viewed by 192
Abstract
The cast nickel-based superalloy K417G exhibits excellent high-temperature strength, but non-equilibrium solidification during casting can cause defects such as irreparable interdendritic microporosity, which significantly degrades its fatigue and creep properties. This study uses hot isostatic pressing (HIP) to eliminate internal flaws such as [...] Read more.
The cast nickel-based superalloy K417G exhibits excellent high-temperature strength, but non-equilibrium solidification during casting can cause defects such as irreparable interdendritic microporosity, which significantly degrades its fatigue and creep properties. This study uses hot isostatic pressing (HIP) to eliminate internal flaws such as porosity in the K417G alloy, aiming to improve its mechanical properties. We investigated the microstructure and mechanical properties of K417G under two thermal conditions: solution heat treatment (SHT) and hot isostatic pressing (HIP). The results indicate that HIP significantly reduces microporosity. Compared to SHT, HIP improves the mechanical performance of K417G. The creep fracture mechanism shifts from intergranular brittle fracture (SHT) to ductile fracture (HIP). Consequently, HIP increases the alloy′s creep life approximately threefold and raises its fatigue limit by about 20 MPa. This improvement is attributed to pore density reduction, which decreases stress concentration zones and homogenizes the microstructure, thereby impeding fatigue crack nucleation and extending the crack incubation period. Full article
(This article belongs to the Special Issue Microstructure and Characterization of Crystalline Materials)
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21 pages, 3422 KiB  
Article
Techno-Economic Optimization of a Grid-Tied PV/Battery System in Johannesburg’s Subtropical Highland Climate
by Webster J. Makhubele, Bonginkosi A. Thango and Kingsley A. Ogudo
Sustainability 2025, 17(14), 6383; https://doi.org/10.3390/su17146383 - 11 Jul 2025
Viewed by 325
Abstract
With rising energy costs and the need for sustainable power solutions in urban South African settings, grid-tied renewable energy systems have become viable alternatives for reducing dependence on traditional grid supply. This study investigates the techno-economic feasibility of a grid-connected hybrid photovoltaic (PV) [...] Read more.
With rising energy costs and the need for sustainable power solutions in urban South African settings, grid-tied renewable energy systems have become viable alternatives for reducing dependence on traditional grid supply. This study investigates the techno-economic feasibility of a grid-connected hybrid photovoltaic (PV) and battery storage system designed for a commercial facility located in Johannesburg, South Africa—an area characterized by a subtropical highland climate. We conducted the analysis using the HOMER Grid software and evaluated the performance of the proposed PV/battery system against the baseline grid-only configuration. Simulation results indicate that the optimal systems, comprising 337 kW of flat-plate PV and 901 kWh of lithium-ion battery storage, offers a significant reduction in electricity expenditure, lowering the annual utility cost from $39,229 to $897. The system demonstrates a simple payback period of less than two years and achieves a net present value (NPV) of approximately $449,491 over a 25-year project lifespan. In addition to delivering substantial cost savings, the proposed configuration also enhances energy resilience. Sensitivity analyses were conducted to assess the impact of variables such as inflation rate, discount rate, and load profile fluctuations on system performance and economic returns. The results affirm the suitability of hybrid grid-tied PV/battery systems for cost-effective, sustainable urban energy solutions in climates with high solar potential. Full article
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16 pages, 377 KiB  
Article
Towards Improved Eye Movement Biometrics: Investigating New Features with Neural Networks
by Katarzyna Harezlak and Ewa Pluciennik
Sensors 2025, 25(14), 4304; https://doi.org/10.3390/s25144304 - 10 Jul 2025
Viewed by 193
Abstract
Providing protected access to many everyday-used resources is becoming increasingly necessary. Research on applying eye movement for this purpose has been conducted for many years. However, due to technological advancements and the lack of stable solutions, subsequent explorations remain valid. The presented work [...] Read more.
Providing protected access to many everyday-used resources is becoming increasingly necessary. Research on applying eye movement for this purpose has been conducted for many years. However, due to technological advancements and the lack of stable solutions, subsequent explorations remain valid. The presented work is one of such studies. Two methods of biometric identification based on eye movements that utilize neural networks have been developed. In the first case, a feature vector was constructed from a 100-element time series depicting eye movement dynamics, which included velocity, acceleration, jerk, their point-to-point percentage changes, and frequency-domain representations. The same eye movement dynamic features were used in the second method, but this time, statistical values were calculated based on the previously defined time series. Long Short-Term Memory (LSTM) and dense networks were used in the user identification task in the first and second approaches, respectively. In the exploration, the publicly available GazeBase dataset was used, from which data collected for the ‘jumping point’ stimulus were chosen. The obtained results are very promising, with an accuracy of 96% for the LSTM model and the time series feature vector set and 76% for the second method. They were achieved over a three-year time span of eye movement recordings; however, different time periods were investigated, as well as various numbers of stimulus positions. Full article
(This article belongs to the Special Issue New Trends in Biometric Sensing and Information Processing)
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