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In wind tunnel testing, an active vibration suppression system based on piezoelectric actuators is an effective means to ensure stable operation. However, in a cryogenic wind tunnel testing environment, the performance of piezoelectric actuators degrades significantly when they are exposed to cold temperatures and subjected to uneven cooling. This is particularly problematic during real-time changes in the attack angle of a test model. To ensure the reliable operation of wind tunnel tests, an active–passive hybrid thermal control method is proposed in this paper. First, the insulation and heating structure was designed based on the thermal analysis results. Then, combining simulation and measured data, the temperature field was reconstructed in real time using a recurrent neural network algorithm. Next, considering the non-uniform heat dissipation of the system, a thermal allocation module was designed based on digital–physical integration to actively control the overall and localized heat. Finally, a heat preservation performance test platform was established to conduct cooling experiments in a small-scale cryogenic wind tunnel. The results indicated that the proposed thermal control method reduced the average cooling rate of the system by 97% and improved the overall temperature uniformity by approximately 94.23%. Full article

(This article belongs to the Section Aeronautics)

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28 pages, 100729 KB

Open AccessArticle

A Lightweight Morel Detection Method Based on Improved YOLOv13n for Complex Agroforestry Cultivation Scenes

by Zixuan Wu and Cheng Zeng

Agriculture 2026, 16(13), 1391; https://doi.org/10.3390/agriculture16131391 (registering DOI) - 25 Jun 2026

Abstract

Morel detection in agroforestry cultivation scenes remains challenging because soil-background camouflage, illumination variation, and dense clustered growth can lead to missed small targets and false positives in background regions. This study proposes Morel-YOLO, a lightweight morel detection method based on YOLOv13n for agricultural perception. The model retains the original multi-scale feature-fusion framework and introduces three targeted modifications: a StarNet backbone for reducing redundant computation, a DSC3k2_DWRSeg module in the shallow P

_{3}

branch for strengthening fine-grained texture and small-target representation, and a Detect_MBConv head for reducing prediction-branch overhead while preserving detection accuracy. On the test set, Morel-YOLO achieves 91.9% precision, 86.6% recall, 93.6% mAP

_{50}

, and 70.8% mAP

_{50 - - 95}

, improving mAP

_{50 - - 95}

by 1.3 percentage points over YOLOv13n. The model contains 1.48 M parameters, has a model size of 3.31 MB, and requires 6.2 GFLOPs. On the Small-hard and Dense-hard subsets, mAP

_{50 - - 95}

reaches 69.1% and 66.8%, respectively, corresponding to gains of 1.5 and 1.3 percentage points over the baseline. Under IoU = 0.75, both false positives and false negatives are also reduced on the two hard subsets. These results suggest that Morel-YOLO improves the balance among detection accuracy, robustness, and model compactness on the evaluated dataset; however, its practical deployment on embedded agricultural platforms still requires dedicated on-device validation. Full article

(This article belongs to the Section Artificial Intelligence and Digital Agriculture)

21 pages, 2084 KB

Open AccessArticle

Development of the Nature Impact Mental Health Intervention for People Experiencing Mild to Moderate Anxiety, Depression, and/or Stress—Co-Producing a Programme Theory and Logic Model

by Louise S. Madsen, Dorthe V. Poulsen, Knud Ryom, Lisa Gregersen Oestergaard, Thomas Maribo and Nanna Holt Jessen

Healthcare 2026, 14(13), 1861; https://doi.org/10.3390/healthcare14131861 (registering DOI) - 25 Jun 2026

Abstract

Background: Nature-based health interventions (NBHIs) show promising potential for supporting people experiencing mild to moderate anxiety, depression, and stress. However, their underlying programme theories are rarely made explicit, limiting transparency, implementation, and transferability within healthcare contexts. The Nature Impact Mental Health Intervention is a context-adapted, nature-based programme designed to support mental health and well-being. This article aims to describe its development through a structured co-production process and presents its programme theory and logic model. Methods: The co-production-based development process followed a three-stage framework. Stage 1 established a scientific foundation through a systematic review, stakeholder analysis, dialogue meetings, and a Delphi study to synthesise evidence and identify knowledge gaps. Stage 2 involved a co-production workshop with practice partners and researchers to translate evidence and refine intervention components. Stage 3 consolidated outputs and site visits into an operational intervention catalogue for prototyping the resulting programme theory and logic model. Results: The co-production process yielded a coherent programme theory comprising clearly defined mechanisms of change and aligned intervention activities. These were iteratively refined through workshops and prototyping, resulting in a consolidated logic model that articulates hypothesised causal pathways linking activities to outcomes. The model also provides a practical framework for guiding subsequent feasibility testing, implementation, and evaluation across contexts. Conclusions: This study demonstrates a transparent development process for co-producing a programme theory and logic model for NBHIs. The resulting model provides a theoretically grounded and implementation-sensitive foundation for subsequent feasibility testing and contributes methodological guidance for integrating NBHIs within healthcare systems. Full article

(This article belongs to the Special Issue Outdoor and Nature Therapy)

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30 pages, 3848 KB

Open AccessArticle

Effects of Repeated Contrast Therapy on Forearm Microcirculatory and Neuromechanical Recovery After Climbing-Specific Fatigue in Amateur Climbers: A Randomized Controlled Trial

by Magdalena Hagner-Derengowska, Bartłomiej Kacprzak, Anna Michalska, Agnieszka Połaniecek, Carla Gonçalves and Robert Trybulski

J. Clin. Med. 2026, 15(13), 4970; https://doi.org/10.3390/jcm15134970 (registering DOI) - 25 Jun 2026

Abstract

Objective: To determine whether contrast therapy improves recovery after climbing-specific forearm fatigue in amateur climbers. Methods: In a randomized repeated-measures trial, 40 climbers were allocated to passive recovery (n = 20) or Game Ready contrast therapy (n = 20). Both groups completed a fixed-task intermittent fingerboard protocol on a 20 mm edge using a half-crimp grip, with 7 s of work and 3 s of rest for five sets; the load was not individualized to climbing-specific maximal finger-flexor force. The intervention group received bilateral forearm treatment consisting of alternating 1 min cold (3 °C) and heat (45 °C) phases combined with pneumatic compression ranging from 15 to 75 mmHg. Sessions lasted 20 min and were administered immediately after post-fatigue testing, at 24 h and 48 h, and then three times weekly on alternate days for 8 weeks, for a total of 27 sessions. Outcomes were assessed at baseline, immediately after fatigue, at 24 h and 48 h, and after 8 weeks. Outcomes included perfusion, reactive hyperemia, stiffness, pressure pain threshold, grip strength, perceived recovery, creatine kinase, and interleukin-6. Results: Immediate post-fatigue responses were comparable. Contrast therapy produced greater 24 h and 48 h resting perfusion responses (+7.28 percentage points, 95% CI 6.58 to 7.98; +7.62, 95% CI 6.94 to 8.31; both adjusted p < 0.001). At week 8, peak hyperemic perfusion improved more with contrast therapy (+6.21 PU, 95% CI 5.62 to 6.79; p < 0.001). Recovery favored contrast therapy for stiffness at 48 h (−71.7 N/m, 95% CI −75.6 to −67.8), pressure pain threshold at week 8 (+8.1 N/cm², 95% CI 7.3 to 8.8), and grip strength at 48 h (+7.8 kgf, 95% CI 7.3 to 8.3; all p < 0.001). CK and IL-6 differences were transient, and no serious adverse events or intervention-related discontinuations were recorded. Conclusions: Contrast therapy was associated with more favorable cutaneous perfusion, post-occlusive reactive hyperemia-derived, and neuromechanical recovery outcomes, whereas biochemical differences were limited and time-dependent. The vascular findings do not establish improved endothelial function or nitric-oxide-mediated vasodilation because these mechanisms were not directly assessed. Trial registration: ISRCTN49499065 on 23 June 2025. Full article

(This article belongs to the Special Issue Exercise, Injury and Rehabilitation: Integrated Perspectives in Sports Medicine)

17 pages, 4861 KB

Open AccessArticle

Preliminary Tests on Recently Selected Poplar Clones from Linear Plantation for Plywood Production

by Silvana Calvano, Sara Bergante, Alberto Bombieri, Pier Mario Chiarabaglio, Corrado Cremonini, Francesco Negro, Daniele Rizza and Roberto Zanuttini

Forests 2026, 17(7), 741; https://doi.org/10.3390/f17070741 (registering DOI) - 25 Jun 2026

Abstract

Despite the significant reduction in the overall cultivated area registered in recent decades, poplar still plays an important economic role in the Po Valley–Italy, where many farms involved in the plantation of this species are present, and the leading wood-processing industries are located. This paper describes the current organization of the poplar plywood wood-chain and explores the challenges in introducing new cultivars into the sector. In particular, it analyzes the main physico-mechanical properties of solid wood from five selected poplar clones (‘Dvina’, ‘Lux’, ‘Mella’, ‘Soligo’, ‘Taro’) that are characterized by fast growth, more sustainable agronomic practices, and increased disease resistance. These clones were cultivated in a seven-year-old linear plantation located in Northern Italy. This model, widely used in the past, is being re-proposed as a complement to the traditional system with square planting distances. The peeling yields and some performances of plywood manufactured from their veneers were also investigated. Results indicate that all clones have a much higher (from +30% to +56%) wood basic density than the ‘I-214’, which remains the lighter and preferred reference. These clones appeared also suitable for rotary cutting, but only ‘Lux’ and ‘Soligo’, and to a lesser extent ‘Mella’, provided veneers of the best quality class. Interesting mechanical features were registered for the sample plywood produced, especially in relation to the age of the harvested timber, which reached a diameter adequate for processing in a shorter time compared to the turnover adopted in conventional plantations. Except for ‘Dvina’, for all the clones, bending MOE and MOR were found to be comparable with those of spruce plywood made of similar thickness and the same lay-up. The findings suggest that the availability of new poplar cultivars and that of different cultivation models designed to enhance fast growth, when supported by targeted research and cooperation among multiple stakeholders (including farmers and industrial manufacturers), can lead to new applications where their plywood performances are valued. This, in turn, allows the resulting panels to meet specific needs in previously unexplored sectors, offering additional market opportunities. Full article

(This article belongs to the Special Issue Performance Testing of Wood and Wood-Based Materials)

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27 pages, 2146 KB

Open AccessArticle

Green Synthesis of Silver Nanoparticles by Using Various Reducing Agents

by Daniela Pricop, Mihaela Racuciu, Catalina Radu, Gabriel Ababei, Dumitru Daniel Herea, Simona Dunca, Lacramioara Oprica, Mirela Nistor, Daniel Timpu, Silvestru-Bogdanel Munteanu and Dorina Creanga

Appl. Sci. 2026, 16(13), 6387; https://doi.org/10.3390/app16136387 (registering DOI) - 25 Jun 2026

Abstract

The experiments aimed at the green synthesis of silver nanoparticles (AgNPs) with various reducers like plant extracts and glucose and the evaluation of their antimicrobial efficiency versus their nanotoxicity. Precursor silver ions were reduced with extracts of Coffea arabica leaves, Thuja orientalis cones, and Cirsium arvense roots as well as with glucose. The AgNP microstructural properties were analyzed with transmission electron microscopy and dynamic light scattering that highlighted fine granulation (23 to 28 nm) and electrical stability (Zeta potential of −15 to −25 mV) while optical and spectral investigations like dark-field microscopy, UV-Vis spectroscopy and FTIR proved specific surface properties. Since cytotoxicity is related to the fate of AgNPs in the environment after their uses, we highlighted the presence of chromosomal alterations in the meristematic tissues of maize roots, such as delayed and expelled chromosomes, chromosome bridges, multi-polar anaphases, C-metaphases and others. Silver nanoparticle use in biomedical applications and antimicrobial activity against Gram-positive and Gram-negative pathogens was evidenced by the agar diffusion test, which suggested their usefulness in the case of possible antibiotic-resistant microbial strains with available natural ingredients and at low cost. Full article

(This article belongs to the Section Chemical and Molecular Sciences)

21 pages, 2564 KB

Open AccessArticle

Impact of Several Green Manure Species on the Physicochemical Characteristics, Enzymatic Activities, and Microbial Community Composition of Soils Under Protected Cultivation

by Jiahui Yu, Ke Xu, Zhengpeng Li, Xiaojun Wang, Qingbiao Yan, Kaibin Qi, Tianlong Chen and Mei Han

Plants 2026, 15(13), 1965; https://doi.org/10.3390/plants15131965 (registering DOI) - 25 Jun 2026

Abstract

To evaluate the ameliorative effects of different green manure crops on continuously cropped protected pepper soil and to identify suitable green manure species for plateau-protected cultivation systems, a one-factor randomized complete block design was conducted with five treatments: common vetch (L1), pea (L2), hairy vetch (L3), radish (L4), and a control without green manure (CK). Soil physicochemical properties, enzyme activities, and microbial community composition were determined at the full-bloom stage before green manure incorporation. Compared with CK, L1 reduced soil pH from 8.63 to 8.34 and decreased total salt content by 45.5%, increased alkali-hydrolyzable nitrogen by 40.93%, and significantly enhanced catalase activity. L3 increased available phosphorus by 23.72% and urease and sucrase activities by 71.32% and 56.31%, respectively, while significantly affecting fungal β-diversity and community composition. Community composition analysis showed that L3 increased the relative abundances of the bacterial genus Rhizobium and the fungal genus Rhizophagus, while reducing the relative abundance of Ascomycota and several potentially pathogen-associated fungal taxa. Redundancy analysis and Mantel tests indicated that bacterial community composition was mainly associated with soil total salt content, alkaline phosphatase, and available phosphorus, whereas fungal community composition was more closely related to urease and alkaline phosphatase. Random forest analysis and partial least squares path modeling further suggested that sucrase, urease, and catalase were important factors closely associated with changes in the soil quality index (SQI). Overall, common vetch performed better in reducing soil salinity, increasing alkali-hydrolyzable nitrogen, and improving the soil quality index and may therefore be considered a suitable green manure species for improving continuously cropped protected pepper soil on the Qinghai Plateau. Hairy vetch showed advantages in increasing available phosphorus and regulating fungal community composition, indicating its potential suitability for protected soils with limited phosphorus availability. Full article

(This article belongs to the Special Issue New Insights in Production and Utilization of Green Manure Crops)

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19 pages, 1019 KB

Open AccessArticle

Preparation of Monoclonal Antibodies Against Porcine Circovirus Type 2 Capsid Protein and Development of a Blocking ELISA for Detection of the Antibody Against the Virus

by Haifeng Sun, Qingqing Liu, Shuyan Zhai, Biyue Wu, Zicheng Ma, Yangyang Sun, Kaiyuan Ye, Haoyuan Wang, Yanni Gao, Xianwei Wang, Juan Bai and Ping Jiang

Vet. Sci. 2026, 13(7), 617; https://doi.org/10.3390/vetsci13070617 (registering DOI) - 25 Jun 2026

Abstract

Porcine circovirus type 2 (PCV2) is the primary causative agent of a spectrum of porcine circovirus-associated diseases (PCVDs) and remains a major threat to the global swine industry. In this study, ten monoclonal antibodies (mAbs) targeting the Cap protein of PCV2 were generated and characterized. One mAb, designated 4C4, which exhibited high reactivity, strong neutralizing activity, and superior blocking efficacy, was selected for horseradish peroxidase (HRP) labeling. After optimizing the reaction parameters, a blocking ELISA was developed for the detection of the anti-PCV2 antibody. Using receiver operating characteristic (ROC) curve analysis, a cutoff value of 40% was established to distinguish positive from negative serum samples. The sensitivity and specificity of this blocking ELISA method were 98.66% and 100%, respectively. No cross-reactivity was observed with serum antibodies against classical swine fever virus (CSFV), porcine epidemic diarrhea virus (PEDV), porcine deltacoronavirus (PDCoV), porcine reproductive and respiratory syndrome virus (PRRSV), or pseudorabies virus (PRV). Intra-assay and inter-assay repeatability tests yielded coefficients of variation (CVs) all below 10%, confirming the assay's excellent reproducibility. Simultaneous testing of 312 clinical porcine serum samples using the developed bELISA and a commercial indirect ELISA kit revealed an overall coincidence rate of 99.04%. In addition, the percentage inhibition (PI) in the bELISA was strongly correlated with serum anti-PCV2 neutralizing antibody titers. In conclusion, the blocking ELISA developed herein demonstrates high sensitivity, strong specificity, and good reproducibility, serving as a potentially effective tool for the detection of the anti-PCV2 antibody and epidemiological investigation. Full article

42 pages, 30257 KB

Open AccessArticle

Structural Performance of Prefabricated Corrugated Steel Plate Retaining Walls in Alpine Permafrost Regions: Numerical Simulation and Experimental Validation

by Wei Chen, Ting Duan, Lianxia Ma, Bailai Liu, Xiaofei Jia, Fang Chen, Yang Lv and Qingtao Zheng

Buildings 2026, 16(13), 2532; https://doi.org/10.3390/buildings16132532 (registering DOI) - 25 Jun 2026

Abstract

Alpine permafrost and seasonally frozen ground threaten the long-term safe operation of highway infrastructures. Aiming at the structural performance optimization of prefabricated corrugated steel plate retaining walls in alpine permafrost regions, this study adopted finite element numerical simulation combined with field test validation to systematically explore the influences of wall height, plate thickness, corrugation geometry, and tie reinforcement layout on structural deformation and internal force, and carried out targeted parameter optimization. The core innovations include the following: (1) Structural lateral displacement and internal force rise nonlinearly with the increase in wall height, and high retaining walls exhibit an accelerated growth trend of deformation and stress. (2) Increasing plate thickness can effectively reduce structural displacement and stress, while the improvement effect gradually weakens after exceeding a critical thickness. Specifically, when the thickness increases from 4 mm to 5 mm, the displacement decreases by 33.13%. (3) Appropriately increasing corrugation pitch and height improves structural equivalent stiffness and optimizes stress distribution. Increasing the corrugation pitch from 75 mm to 400 mm and corrugation height from 25 mm to 150 mm reduces the maximum horizontal displacement by 52.6%. This demonstrates that larger corrugation profiles significantly improve structural stiffness. For walls higher than 6 m, the spacing should be reduced to 0.8 m × 1.0 m to provide additional lateral restraint. (4) Furthermore, seasonal freeze–thaw cycles and a non-uniform temperature field significantly amplify structural displacement and stress. After 12 months of freeze–thaw cycles, the maximum horizontal displacement increases by 49.7% and the maximum equivalent stress increases by 56.9% compared to the initial state. This study clarifies the parameter control mechanism and temperature coupling effect and provides a reliable theoretical basis and design reference for the engineering application of prefabricated corrugated steel plate retaining walls in alpine permafrost areas. Full article

(This article belongs to the Special Issue Application of New Technologies or Building Materials in Civil Engineering)

24 pages, 3326 KB

Open AccessArticle

Development of a DEM-Based Flexible Plant Model for Mature Peanut Plants

by Dongjie Li, Zengcun Chang, Dongwei Wang, Xu Li, Jiayou Zhang, Haipeng Yan, Baiqiang Zuo and Jialin Hou

Agriculture 2026, 16(13), 1390; https://doi.org/10.3390/agriculture16131390 (registering DOI) - 25 Jun 2026

Abstract

Accurate discrete element method (DEM) modelling of mature peanut plants is essential for simulating peanut harvesting, pod detachment, and harvest-loss formation. However, existing peanut DEM models are usually simplified as isolated pods, rigid cylindrical particles, or partial stem–pod structures, which limits their ability to represent the flexible deformation of vines and pod stalks and the fracture behaviors at the pod–pod stalk junction. In this study, a DEM-based flexible plant model was developed for mature peanut plants. The geometric dimensions, contact parameters, and mechanical properties of peanut pods, pod stalks, and stems were measured through physical experiments. The Hertz–Mindlin model was used for non-bonded contacts, whereas the Hertz–Mindlin with Bonding model was adopted to represent the flexible connections among plant organs and the fracture behaviors of the pod–pod stalk junction. The main DEM parameters were calibrated using Plackett–Burman screening, steepest ascent experiments, and central composite design. The results showed that the tangential stiffness per unit area and tangential critical stress at the pod–pod stalk junction were the dominant factors affecting pod detachment force. The optimized parameter combination was a tangential stiffness per unit area of 4.738 × 10⁵ N/m³ and a tangential critical stress of 9.350 × 10⁵ Pa, corresponding to a simulated tensile force of 6.73 N. Model validation was performed by comparing peanut harvesting simulations with field trials. The relative error of pod loss rate between simulation and field measurement was less than 7.55%, and the t-test result indicated no significant difference between the two datasets (p > 0.05). These results demonstrate that the proposed flexible peanut plant model can effectively characterize pod–pod stalk separation and can provide a reliable DEM modelling basis for peanut harvesting process analysis and equipment optimization. Full article

(This article belongs to the Section Artificial Intelligence and Digital Agriculture)

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29 pages, 14935 KB

Open AccessArticle

Vectorized Evidential Reasoning-Based Multivariate Effluent Quality Prediction for Sustainable Wastewater Treatment Process

by Xuelin Zhang, Xiaoning Huang, Yongdan Zhou, Jun Wu, Xiaobin Xu and Rongjun Liu

Sustainability 2026, 18(13), 6501; https://doi.org/10.3390/su18136501 (registering DOI) - 25 Jun 2026

Abstract

Accurate prediction of multivariate effluent quality is essential for achieving reliable operation and sustainable management of wastewater treatment processes (WWTPs). However, the strong nonlinearity, coupling relationships, and non-prioritized multi-input multi-output (MIMO) characteristics of WWTP pose significant challenges to conventional prediction methods. To address these issues, a vectorized evidential reasoning-based multivariate effluent quality (VER-MEQ) prediction method is proposed. First, a VER model is developed, in which the nonlinear mapping between multiple process variables and multiple effluent quality indicators is established through a vector evidence matrix (VEM), enabling simultaneous online prediction of multiple outputs within a unified inference framework. Subsequently, a structured hybrid initialization (SHI) strategy is introduced to improve the initialization quality of the genetic algorithm, and the VER inference process is incorporated into parameter optimization to enable online model parameter updating, thereby improving prediction performance. The proposed method is validated under sunny, rainy, and stormy operating scenarios. Experimental results demonstrate that VER-MEQ achieves competitive prediction accuracy, provides a transparent belief-based inference process, and maintains preliminary anti-interference performance under the tested conditions. By providing transparent and credible prediction results for effluent ammonia nitrogen (NH₃-N_e) and total nitrogen (TN_e), the proposed framework can support proactive operational decision-making, improve effluent compliance, reduce the risk of nutrient discharge, and contribute to the sustainable operation of WWTPs. Full article

(This article belongs to the Section Sustainable Water Management)

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24 pages, 580 KB

Open AccessArticle

Understanding Product Attachment to Battery Electric Vehicles: Evidence from Indonesian Owners

by Eko Yulianto, Mts Arief, Sri Bramantoro Abdinagoro and Asnan Furinto

World Electr. Veh. J. 2026, 17(7), 331; https://doi.org/10.3390/wevj17070331 (registering DOI) - 25 Jun 2026

Abstract

Battery electric vehicle (BEV) adoption does not always result in long-term ownership, because some owners may return to internal combustion engine vehicles after purchase. This study examines how internal customer factors influence the formation of product attachment, an emotional bond between owners and their BEVs. This issue is important because such attachment may support long-term commitment, expressed through advocacy and loyalty after adoption. The study focuses on instrumental, affective, and symbolic car use motivation, customer innovativeness, and direct experience. Data were collected through face-to-face surveys with 392 Indonesian BEV owners who had driven their vehicles for more than 5000 km. ANOVA and PLS-SEM were used to examine segment differences and test the structural model. Affective motivation had the largest positive path coefficient for product attachment (β = 0.451), followed by symbolic motivation (β = 0.370), direct experience (β = 0.301), and instrumental motivation (β = 0.229). Customer innovativeness was not significant (β = −0.026, p = 0.324). Product attachment showed strong relationships with customer advocacy (β = 0.649) and loyalty (β = 0.686). This study extends the product attachment literature by explaining how internal customer factors are related to the development of product attachment and the extent to which owners become attached to their BEVs. Full article

(This article belongs to the Section Marketing, Promotion and Socio Economics)

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38 pages, 5423 KB

Open AccessArticle

ROIV-SLAM: Rotation-Optimized Inertial–Visual SLAM for a Non-Coaxial Two-Wheeled Robot Under Roll Disturbances

by Chong Feng, Cheng Ren, Wenbo Gao, Zhan Shi, Chunjuan Bo, Chang Kou and Zhun Feng

Sensors 2026, 26(13), 4053; https://doi.org/10.3390/s26134053 (registering DOI) - 25 Jun 2026

Abstract

To address the problem of high-frequency roll disturbances generated during dynamic balancing in non-coaxial two-wheeled robots, this paper proposes a Rotation-Optimized Inertial–Visual SLAM system (ROIV-SLAM) for robust state estimation. The proposed approach adopts a decoupled architecture for translation and rotation estimation. In the front-end, an Extended Kalman Filter (EKF) is employed to fuse LiDAR, an inertial measurement unit (IMU), and wheel odometry to obtain an initial translation estimate. Meanwhile, a physical manifold constraint is constructed using the gravity vector and surface normals extracted from RGB-D point clouds, supporting stable rotation estimation under high-frequency disturbances through Lie-group-based optimization. In the back-end, a factor graph is established, and loop closure robustness is enhanced through vision–LiDAR scan matching. Experimental results indicate that ROIV-SLAM achieves improved trajectory consistency with respect to the optimized reference trajectory and more robust mapping performance compared with the evaluated baseline approaches in the tested scenarios. The results further suggest that introducing task-specific physical dynamic constraints and a decoupled estimation mechanism helps suppress high-frequency motion noise inherent to balancing robots, thereby improving the robustness of state estimation in complex environments. Full article

(This article belongs to the Section Sensors and Robotics)

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15 pages, 8191 KB

Open AccessArticle

Effect of Annealing Temperature on Microstructure and Properties of Ti–Microalloyed High–Strength Steel for Photovoltaic Mounting Structures

by Xixiao Liu, Jie Liu, Lan Su, Yundong Wang, Xiangting Zhang and Zhengzhi Zhao

Metals 2026, 16(7), 700; https://doi.org/10.3390/met16070700 (registering DOI) - 25 Jun 2026

Abstract

Photovoltaic mounting structures operate in harsh environments, demanding high strength and elongation. However, a strength–graded product series within the same composition is lacking. Through Ti microalloying and heat treatment, we developed steels with strengths of 500–800 MPa and studied annealing effects at 640–740 °C. Scanning Electron Microscope (SEM) shows ferrite and cementite: with increasing temperature, ferrite changes from elongated to equiaxed via recovery and recrystallization, while cementite remains finely dispersed along grain boundaries. Transmission Electron Microscope (TEM) reveals TiC precipitates, which decrease in number but increase in size at higher temperatures. Grain refinement strengthening, dislocation strengthening, and precipitation strengthening are the primary strengthening mechanisms, contributing 91.2% and 94.4% to the yield strength after annealing at 640 °C and 720 °C, respectively. Within a wide annealing temperature range, the tensile strength fully covers the 550–650–750–800 MPa grades, with the corresponding elongation fluctuating between 12.4% and 25.3%, achieving a good strength–ductility balance. In summary, simply adding a single Ti element and adjusting the annealing temperature allows for the production of test steels with strengths ranging from 500 to 800 MPa and matched elongation. This approach not only reduces costs but also provides experimental evidence for the process development of a series of new steels for photovoltaic mounting brackets. Full article

(This article belongs to the Special Issue Recent Advances in High-Performance Steel (2nd Edition))

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60 pages, 3227 KB

Open AccessArticle

A Boundary-Adapted Legendre–Galerkin Method for Nonlinear Caputo Reaction–Diffusion Equations with Non-Local Integral Boundary Conditions

by Weaam Alhejaili, Kawthar Alsa’di and Álvaro H. Salas

Fractal Fract. 2026, 10(7), 434; https://doi.org/10.3390/fractalfract10070434 (registering DOI) - 25 Jun 2026

Abstract

This paper studies nonlinear time-fractional reaction–diffusion equations with Caputo memory and non-local integral boundary conditions on a bounded interval. The aim is to formulate a boundary-compatible well-posedness framework and to construct a high-order temporal approximation that can be coupled with a constraint-preserving spectral spatial discretization. The analytical part proves boundedness of the non-local boundary functionals, states compatibility assumptions, and introduces a finite-dimensional nondegeneracy condition for an explicit polynomial lifting. Under a sectorial non-local elliptic realization and a global Lipschitz reaction term, existence, uniqueness, stability, and continuous dependence of mild solutions are obtained by fractional resolvent estimates and fractional Gronwall inequalities. The main novelty is the combined construction of an explicit polynomial lifting for integral boundary constraints, a constraint-preserving Legendre–Galerkin basis, and a high-order Beta-window temporal quadrature together with a discrete stability condition that accounts for sign-changing weights. The numerical evidence shows high-order behavior for smooth Caputo benchmarks, accurate enforcement of the non-local boundary constraints, and improved accuracy over the classical

L 1

approximation in the reported tests. The stability discussion identifies the discrete coercivity condition required for the sign-changing Beta-window weights. Full article

(This article belongs to the Special Issue Numerical Solutions of Caputo-Type Fractional Differential Equations and Derivatives, Second Edition)

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