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18 pages, 7274 KiB  
Article
Functional Compression Fabrics with Dual Scar-Suppressing and Antimicrobial Properties: Microencapsulation Design and Performance Evaluation
by Lihuan Zhao, Changjing Li, Mingzhu Yuan, Rong Zhang, Xinrui Liu, Xiuwen Nie and Bowen Yan
J. Funct. Biomater. 2025, 16(8), 287; https://doi.org/10.3390/jfb16080287 - 5 Aug 2025
Abstract
Pressure therapy combined with silicone has a significant effect on scar hyperplasia, but limitations such as long-term wearing of compression garments (CGs) can easily cause bacterial infection, cleanliness, and lifespan problems of CGs caused by the tedious operation of applying silicone. In this [...] Read more.
Pressure therapy combined with silicone has a significant effect on scar hyperplasia, but limitations such as long-term wearing of compression garments (CGs) can easily cause bacterial infection, cleanliness, and lifespan problems of CGs caused by the tedious operation of applying silicone. In this study, a compression garment fabric (CGF) with both inhibition of scar hyperplasia and antibacterial function was prepared. A polydimethylsiloxane (PDMS)-loaded microcapsule (PDMS-M) was prepared with chitosan quaternary ammonium salt (HACC) and sodium alginate (SA) as wall materials and PDMS as core materials by the complex coagulation method. The PDMS-Ms were finished on CGF and modified with (3-aminopropyl)triethoxysilane (APTES) to obtain PDMS-M CGF, which was further treated with HACC to produce PDMS-M-HACC CGF. X-ray Photoelectron Spectroscopy(XPS) and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the formation of covalent bonding between PDMS-M and CGF. The PDMS-M CGF exhibited antibacterial rates of 94.2% against Gram-negative bacteria Escherichia coli (E. coli, AATCC 6538) and of 83.1% against Gram-positive bacteria Staphylococcus aureus (S. aureus, AATCC 25922). The antibacterial rate of PDMS-M-HACC CGF against both E. coli and S. aureus reached 99.9%, with wash durability reaching grade AA for E. coli and approaching grade A for S. aureus. The finished CGF maintained good biocompatibility and showed minimal reduction in moisture permeability compared to unfinished CGF, though with decreased elastic recovery, air permeability and softness. The finished CGF of this study is expected to improve the therapeutic effect of hypertrophic scars and improve the quality of life of patients with hypertrophic scars. Full article
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23 pages, 3106 KiB  
Article
Preparation of a Nanomaterial–Polymer Dynamic Cross-Linked Gel Composite and Its Application in Drilling Fluids
by Fei Gao, Peng Xu, Hui Zhang, Hao Wang, Xin Zhao, Xinru Li and Jiayi Zhang
Gels 2025, 11(8), 614; https://doi.org/10.3390/gels11080614 - 5 Aug 2025
Viewed by 25
Abstract
During the process of oil and gas drilling, due to the existence of pores or micro-cracks, drilling fluid is prone to invade the formation. Under the action of hydration expansion of clay in the formation and liquid pressure, wellbore instability occurs. In order [...] Read more.
During the process of oil and gas drilling, due to the existence of pores or micro-cracks, drilling fluid is prone to invade the formation. Under the action of hydration expansion of clay in the formation and liquid pressure, wellbore instability occurs. In order to reduce the wellbore instability caused by drilling fluid intrusion into the formation, this study proposed a method of forming a dynamic hydrogen bond cross-linked network weak gel structure with modified nano-silica and P(AM-AAC). The plugging performance of the drilling fluid and the performance of inhibiting the hydration of shale were evaluated through various experimental methods. The results show that the gel composite system (GCS) effectively optimizes the plugging performance of drilling fluid. The 1% GCS can reduce the linear expansion rate of cuttings to 14.8% and increase the recovery rate of cuttings to 96.7%, and its hydration inhibition effect is better than that of KCl and polyamines. The dynamic cross-linked network structure can significantly increase the viscosity of drilling fluid. Meanwhile, by taking advantage of the liquid-phase viscosity effect and the physical blocking effect, the loss of drilling fluid can be significantly reduced. Mechanism studies conducted using zeta potential measurement, SEM analysis, contact angle measurement and capillary force assessment have shown that modified nano-silica stabilizes the wellbore by physically blocking the nano-pores of shale and changing the wettability of the shale surface from hydrophilic to hydrophobic when the contact angle exceeds 60°, thereby reducing capillary force and surface free energy. Meanwhile, the dynamic cross-linked network can reduce the seepage of free water into the formation, thereby significantly lowering the fluid loss of the drilling fluid. This research provides new insights into improving the stability of the wellbore in drilling fluids. Full article
(This article belongs to the Special Issue Advanced Gels for Oil Recovery (2nd Edition))
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17 pages, 1203 KiB  
Communication
Efficacy of a Novel Lactiplantibacillus plantarum Strain (LP815TM) in Reducing Canine Aggression and Anxiety: A Randomized Placebo-Controlled Trial with Qualitative and Quantitative Assessment
by Emmanuel M. M. Bijaoui and Noah P. Zimmerman
Animals 2025, 15(15), 2280; https://doi.org/10.3390/ani15152280 - 4 Aug 2025
Viewed by 155
Abstract
Behavioral issues in domestic dogs represent a significant welfare concern affecting both canines and their caregivers, with prevalence rates reported to range from 34 to 86% across the population. Current treatment options, including selective serotonin reuptake inhibitors (SSRIs) like fluoxetine, often present limitations [...] Read more.
Behavioral issues in domestic dogs represent a significant welfare concern affecting both canines and their caregivers, with prevalence rates reported to range from 34 to 86% across the population. Current treatment options, including selective serotonin reuptake inhibitors (SSRIs) like fluoxetine, often present limitations including adverse effects and delayed efficacy. This randomized, placebo-controlled (maltodextrin) study investigated the effects of a novel Lactiplantibacillus plantarum strain (LP815TM) on canine behavioral concerns through gut–brain axis modulation. Home-based dogs (n = 40) received either LP815TM (n = 28) or placebo (n = 12) daily for 4 weeks, with behavioral changes assessed using the comprehensive Canine Behavioral Assessment & Research Questionnaire (C-BARQ) and continuous activity monitoring. After the intervention period, dogs receiving LP815TM showed significant improvements in aggression (p = 0.0047) and anxiety (p = 0.0005) compared to placebo controls. These findings were corroborated by objective activity data, which demonstrated faster post-departure settling, reduced daytime sleep, and improved sleep consistency in the treatment group. Throughout >1120 administered doses, no significant adverse events were reported, contrasting favorably with pharmaceutical alternatives. The concordance between our findings and previous research using different L. plantarum strains suggests a consistent biological mechanism, potentially involving GABA production and vagal nerve stimulation. These results indicate that LP815TM represents a promising, safe alternative for addressing common canine behavioral concerns with potential implications for improving both canine welfare and the human–animal bond. Full article
(This article belongs to the Section Companion Animals)
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14 pages, 1959 KiB  
Article
Influence of Molecular Weight of Anthraquinone Acid Dyes on Color Strength, Migration, and UV Protection of Polyamide 6 Fabrics
by Nawshin Farzana, Abu Naser Md Ahsanul Haque, Shamima Akter Smriti, Abu Sadat Muhammad Sayem, Fahmida Siddiqa, Md Azharul Islam, Md Nasim and S M Kamrul Hasan
Physchem 2025, 5(3), 31; https://doi.org/10.3390/physchem5030031 - 4 Aug 2025
Viewed by 139
Abstract
Anthraquinone acid dyes are widely used in dyeing polyamide due to their good exhaustion and brightness. While ionic interactions primarily govern dye–fiber bonding, the molecular weight (Mw) of these dyes can significantly influence migration, apparent color strength, and fastness behavior. This study offers [...] Read more.
Anthraquinone acid dyes are widely used in dyeing polyamide due to their good exhaustion and brightness. While ionic interactions primarily govern dye–fiber bonding, the molecular weight (Mw) of these dyes can significantly influence migration, apparent color strength, and fastness behavior. This study offers comparative insight into how the Mw of structurally similar anthraquinone acid dyes impacts their diffusion, fixation, and functional outcomes (e.g., UV protection) on polyamide 6 fabric, using Acid Blue 260 (Mw~564) and Acid Blue 127:1 (Mw~845) as representative low- and high-Mw dyes. The effects of dye concentration, pH, and temperature on color strength (K/S) were evaluated, migration index and zeta potential were measured, and UV protection factor (UPF) and FTIR analyses were used to assess fabric functionality. Results showed that the lower-Mw dye exhibited higher migration tendency, particularly at increased dye concentrations, while the higher-Mw dye demonstrated greater color strength and superior wash fastness. Additionally, improved UPF ratings were associated with higher-Mw dye due to enhanced light absorption. These findings offer practical insights for optimizing acid dye selection in polyamide coloration to balance color performance and functional attributes. Full article
(This article belongs to the Section Surface Science)
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18 pages, 4136 KiB  
Article
Interfacial Electric Fields and Chemical Bonds in Ti3C2O-Crafted AgI/MoS2 Direct Z-Scheme Heterojunction Synergistically Expedite Photocatalytic Performance
by Suxing Jiao, Tianyou Chen, Yiran Ying, Yincheng Liu and Jing Wu
Catalysts 2025, 15(8), 740; https://doi.org/10.3390/catal15080740 - 3 Aug 2025
Viewed by 218
Abstract
The photocatalytic performance of heterojunctions is often restricted by inferior contact interface and low charge transfer efficiency. In this work, Ti3C2O MXene was crafted with AgI/MoS2 to produce a Z-scheme heterojunction (AgI/MoS2/Ti3C2O). [...] Read more.
The photocatalytic performance of heterojunctions is often restricted by inferior contact interface and low charge transfer efficiency. In this work, Ti3C2O MXene was crafted with AgI/MoS2 to produce a Z-scheme heterojunction (AgI/MoS2/Ti3C2O). Interfacial electric fields and chemical bonds were proven to exist in the heterojunction. The interfacial electric fields supplied a powerful driving force, and the interfacial Ti-O-Mo bonds served as an atomic-level channel for synergistically expediting the vectorial transfer of photogenerated carriers. As a result, AgI/MoS2/Ti3C2O exhibited significantly improved photocatalytic activity, demonstrating a high H2O2 production rate of 700 μmol·g−1·h−1 and a rapid degradation of organic pollutants. Full article
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38 pages, 4692 KiB  
Review
Progress and Challenges in the Process of Using Solid Waste as a Catalyst for Biodiesel Synthesis
by Zhaolin Dong, Kaili Dong, Haotian Li, Liangyi Zhang and Yitong Wang
Molecules 2025, 30(15), 3243; https://doi.org/10.3390/molecules30153243 - 1 Aug 2025
Viewed by 201
Abstract
Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various [...] Read more.
Biodiesel, as one of the alternatives to fossil fuels, faces significant challenges in large-scale industrial production due to its high production costs. In addition to raw material costs, catalyst costs are also a critical factor that cannot be overlooked. This review summarizes various methods for preparing biodiesel catalysts from solid waste. These methods not only enhance the utilization rate of waste but also reduce the production costs and environmental impact of biodiesel. Finally, the limitations of waste-based catalysts and future research directions are discussed. Research indicates that solid waste can serve as a catalyst carrier or active material for biodiesel production. Methods such as high-temperature calcination, impregnation, and coprecipitation facilitate structural modifications to the catalyst and the formation of active sites. The doping of metal ions not only alters the catalyst’s acid-base properties but also forms stable metal bonds with functional groups on the carrier, thereby maintaining catalyst stability. The application of microwave-assisted and ultrasound-assisted methods reduces reaction parameters, making biodiesel production more economical and sustainable. Overall, this study provides a scientific basis for the reuse of solid waste and ecological protection, emphasizes the development potential of waste-based catalysts in biodiesel production, and offers unique insights for innovation in this field, thereby accelerating the commercialization of biodiesel. Full article
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17 pages, 5839 KiB  
Article
Hydrogen Bond-Regulated Rapid Prototyping and Performance Optimization of Polyvinyl Alcohol–Tannic Acid Hydrogels
by Xiangyu Zou and Jun Huang
Gels 2025, 11(8), 602; https://doi.org/10.3390/gels11080602 - 1 Aug 2025
Viewed by 247
Abstract
Traditional hydrogel preparation methods typically require multiple steps and certain external stimuli. In this study, rapid and stable gelation of polyvinyl alcohol (PVA)-tannic acid (TA)-based hydrogels was achieved through the regulation of hydrogen bonds. The cross-linking between PVA and TA is triggered by [...] Read more.
Traditional hydrogel preparation methods typically require multiple steps and certain external stimuli. In this study, rapid and stable gelation of polyvinyl alcohol (PVA)-tannic acid (TA)-based hydrogels was achieved through the regulation of hydrogen bonds. The cross-linking between PVA and TA is triggered by the evaporation of ethanol. Rheological testing and analysis of the liquid-solid transformation process of the hydrogel were performed. The gelation onset time (GOT) could be tuned from 10 s to over 100 s by adjusting the ethanol content and temperature. The addition of polyhydroxyl components (e.g., glycerol) significantly enhances the hydrogel’s water retention capacity (by 858%) and tensile strain rate (by 723%), while concurrently increasing the gelation time. Further studies have shown that the addition of alkaline substances (such as sodium hydroxide) promotes the entanglement of PVA molecular chains, increasing the tensile strength by 23% and the fracture strain by 41.8%. The experimental results indicate that the optimized PVA-TA hydrogels exhibit a high tensile strength (>2 MPa) and excellent tensile properties (~600%). Moreover, the addition of an excess of weakly alkaline substances (such as sodium acetate) reduces the degree of hydrolysis of PVA, enabling the system to form a hydrogel with extrudable characteristics before the ethanol has completely evaporated. This property allows for patterned printing and thus demonstrates the potential of the hydrogel in 3D printing. Overall, this study provides new insights for the application of PVA-TA based hydrogels in the fields of rapid prototyping and strength optimization. Full article
(This article belongs to the Special Issue Synthesis and Applications of Hydrogels (3rd Edition))
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27 pages, 1081 KiB  
Article
Effect of Monomer Mixture Composition on TiCl4-Al(i-C4H9)3 Catalytic System Activity in Butadiene–Isoprene Copolymerization: A Theoretical Study
by Konstantin A. Tereshchenko, Rustem T. Ismagilov, Nikolai V. Ulitin, Yana L. Lyulinskaya and Alexander S. Novikov
Computation 2025, 13(8), 184; https://doi.org/10.3390/computation13080184 - 1 Aug 2025
Viewed by 104
Abstract
Divinylisoprene rubber, a copolymer of butadiene and isoprene, is used as raw material for rubber technical products, combining isoprene rubber’s elasticity and butadiene rubber’s wear resistance. These properties depend quantitatively on the copolymer composition, which depends on the kinetics of its synthesis. This [...] Read more.
Divinylisoprene rubber, a copolymer of butadiene and isoprene, is used as raw material for rubber technical products, combining isoprene rubber’s elasticity and butadiene rubber’s wear resistance. These properties depend quantitatively on the copolymer composition, which depends on the kinetics of its synthesis. This work aims to theoretically describe how the monomer mixture composition in the butadiene–isoprene copolymerization affects the activity of the TiCl4-Al(i-C4H9)3 catalytic system (expressed by active sites concentration) via kinetic modeling. This enables development of a reliable kinetic model for divinylisoprene rubber synthesis, predicting reaction rate, molecular weight, and composition, applicable to reactor design and process intensification. Active sites concentrations were calculated from experimental copolymerization rates and known chain propagation constants for various monomer compositions. Kinetic equations for active sites formation were based on mass-action law and Langmuir monomolecular adsorption theory. An analytical equation relating active sites concentration to monomer composition was derived, analyzed, and optimized with experimental data. The results show that monomer composition’s influence on active sites concentration is well described by a two-step kinetic model (physical adsorption followed by Ti–C bond formation), accounting for competitive adsorption: isoprene adsorbs more readily, while butadiene forms more stable active sites. Full article
(This article belongs to the Special Issue Feature Papers in Computational Chemistry)
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11 pages, 5112 KiB  
Article
Fabrication of a Porous TiNi3 Intermetallic Compound to Enhance Anti-Corrosion Performance in 1 M KOH
by Zhenli He, Yue Qiu, Yuehui He, Qian Zhao, Zhonghe Wang and Yao Jiang
Metals 2025, 15(8), 865; https://doi.org/10.3390/met15080865 (registering DOI) - 1 Aug 2025
Viewed by 175
Abstract
Porous intermetallic compounds have the properties of porous materials as well as a combination of covalent and metallic bonds, and they exhibit high porosity, structural stability, and corrosion resistance. In this work, a porous TiNi3 intermetallic compound was fabricated through reactive synthesis [...] Read more.
Porous intermetallic compounds have the properties of porous materials as well as a combination of covalent and metallic bonds, and they exhibit high porosity, structural stability, and corrosion resistance. In this work, a porous TiNi3 intermetallic compound was fabricated through reactive synthesis of elemental powders. Next, detailed studies of its phase composition and pore structure characteristics at different sintering temperatures, as well as its corrosion behavior against an alkaline environment, were carried out. The results show that the as-prepared porous TiNi3 intermetallic compound has abundant pore structures, with an open porosity of 56.5%, which can be attributed to a combination of the bridging effects of initial powder particles and the Kirkendall effect occurring during the sintering process. In 1 M KOH solution, a higher positive corrosion potential (−0.979 VSCE) and a lower corrosion current density (1.18 × 10−4 A∙cm−2) were exhibited by the porous TiNi3 intermetallic compound, compared to the porous Ni, reducing the thermodynamic corrosion tendency and the corrosion rate. The corresponding corrosion process is controlled by the charge transfer process, and the increased charge transfer resistance value (713.9 Ω⋅cm2) of TiNi3 makes it more difficult to charge-transfer than porous Ni (204.5 Ω⋅cm2), thus decreasing the rate of electrode reaction. The formation of a more stable passive film with the incorporation of Ti contributes to this improved corrosion resistance performance. Full article
(This article belongs to the Special Issue Advanced Ti-Based Alloys and Ti-Based Materials)
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18 pages, 3916 KiB  
Article
Bond Behavior Between Fabric-Reinforced Cementitious Matrix (FRCM) Composites and Different Substrates: An Experimental Investigation
by Pengfei Ma, Shangke Yuan and Shuming Jia
J. Compos. Sci. 2025, 9(8), 407; https://doi.org/10.3390/jcs9080407 - 1 Aug 2025
Viewed by 189
Abstract
This study investigates the bond behavior of fabric-reinforced cementitious matrix (FRCM) composites with three common masonry substrates—solid clay bricks (SBs), perforated bricks (PBs), and concrete hollow blocks (HBs)—using knitted polyester grille (KPG) fabric. Through uniaxial tensile tests of the KPG fabric and FRCM [...] Read more.
This study investigates the bond behavior of fabric-reinforced cementitious matrix (FRCM) composites with three common masonry substrates—solid clay bricks (SBs), perforated bricks (PBs), and concrete hollow blocks (HBs)—using knitted polyester grille (KPG) fabric. Through uniaxial tensile tests of the KPG fabric and FRCM system, along with single-lap and double-lap shear tests, the interfacial debonding modes, load-slip responses, and composite utilization ratio were evaluated. Key findings reveal that (i) SB and HB substrates predominantly exhibited fabric slippage (FS) or matrix–fabric (MF) debonding, while PB substrates consistently failed at the matrix–substrate (MS) interface, due to their smooth surface texture. (ii) Prism specimens with mortar joints showed enhanced interfacial friction, leading to higher load fluctuations compared to brick units. PB substrates demonstrated the lowest peak stress (69.64–74.33 MPa), while SB and HB achieved comparable peak stresses (133.91–155.95 MPa). (iii) The FRCM system only achieved a utilization rate of 12–30% in fabric and reinforcement systems. The debonding failure at the matrix–substrate interface is one of the reasons that cannot be ignored, and exploring methods to improve the bonding performance between the matrix–substrate interface is the next research direction. HB bricks have excellent bonding properties, and it is recommended to prioritize their use in retrofit applications, followed by SB bricks. These findings provide insights into optimizing the application of FRCM reinforcement systems in masonry structures. Full article
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10 pages, 419 KiB  
Brief Report
Pilot Data on Salivary Oxytocin as a Biomarker of LSD Response in Patients with Major Depressive Disorder
by Laure Cazorla, Sylvie Alaux, Caroline Amberger, Cédric Mabilais, Leonice Furtado, Albert Buchard, Gabriel Thorens, Louise Penzenstadler, Daniele Zullino and Tatiana Aboulafia Brakha
Psychoactives 2025, 4(3), 26; https://doi.org/10.3390/psychoactives4030026 - 1 Aug 2025
Viewed by 149
Abstract
Despite growing evidence supporting the efficacy of LSD-assisted psychotherapy in treating major depressive disorder (MDD), identifying reliable psychopharmacological biomarkers remains necessary. Oxytocin, a neuropeptide implicated in social bonding and flexibility, is a promising candidate due to its release following serotonergic psychedelic administration in [...] Read more.
Despite growing evidence supporting the efficacy of LSD-assisted psychotherapy in treating major depressive disorder (MDD), identifying reliable psychopharmacological biomarkers remains necessary. Oxytocin, a neuropeptide implicated in social bonding and flexibility, is a promising candidate due to its release following serotonergic psychedelic administration in healthy individuals; however, its dynamics in psychiatric populations are currently unexplored. This observational pilot study aimed to characterize salivary oxytocin dynamics during a single LSD-assisted psychotherapy session in our patients with treatment-resistant MDD. Participants received 100 or 150 µg LSD, and salivary oxytocin was measured at baseline, 60, 90, and 180 min post-LSD. Concurrently, participants rated subjective drug intensity (0–10 scale) at 60, 90, and 180 min. A linear mixed model revealed significant variation of oxytocin levels over time. Perceived psychedelic intensity also significantly varied over time. This supports oxytocin as a potential biomarker. Larger, controlled trials are warranted to replicate these findings and clarify the mechanistic links between oxytocin dynamics and clinical outcomes, including changes in depressive symptoms and mental flexibility. Full article
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16 pages, 3072 KiB  
Article
Process Development to Repair Aluminum Components, Using EHLA and Laser-Powder DED Techniques
by Adrienn Matis, Min-Uh Ko, Richard Kraft and Nicolae Balc
J. Manuf. Mater. Process. 2025, 9(8), 255; https://doi.org/10.3390/jmmp9080255 - 31 Jul 2025
Viewed by 246
Abstract
The article presents a new AM (Additive Manufacturing) process development, necessary to repair parts made from Aluminum 6061 material, with T6 treatment. The laser Directed Energy Deposition (DED) and Extreme High-Speed Directed Energy Deposition (EHLA) capabilities are evaluated for repairing Al large components. [...] Read more.
The article presents a new AM (Additive Manufacturing) process development, necessary to repair parts made from Aluminum 6061 material, with T6 treatment. The laser Directed Energy Deposition (DED) and Extreme High-Speed Directed Energy Deposition (EHLA) capabilities are evaluated for repairing Al large components. To optimize the process parameters, single-track depositions were analyzed for both laser-powder DED (feed rate of 2 m/min) and EHLA (feed rate 20 m/min) for AlSi10Mg and Al6061 powders. The cross-sections of single tracks revealed the bonding characteristics and provided laser-powder DED, a suitable parameter selection for the repair. Three damage types were identified on the Al component to define the specification of the repair process and to highlight the capabilities of laser-powder DED and EHLA in repairing intricate surface scratches and dents. Our research is based on variation of the powder mass flow and beam power, studying the influence of these parameters on the weld bead geometry and bonding quality. The evaluation criteria include bonding defects, crack formation, porosity, and dilution zone depth. The bidirectional path planning strategy was applied with a fly-in and fly-out path for the hatching adjustment and acceleration distance. Samples were etched for a qualitative microstructure analysis, and the HV hardness was tested. The novelty of the paper is the new process parameters for laser-powder DED and EHLA deposition strategies to repair large Al components (6061 T6), using AlSi10Mg and Al6061 powder. Our experimental research tested the defect-free deposition and the compatibility of AlSi10Mg on the Al6061 substrate. The readers could replicate the method presented in this article to repair by laser-powder DED/EHLA large Al parts and avoid the replacement of Al components with new ones. Full article
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15 pages, 3303 KiB  
Article
Effect of Ozone on Nonwoven Polylactide/Natural Rubber Fibers
by Yulia V. Tertyshnaya, Svetlana G. Karpova and Maria V. Podzorova
Polymers 2025, 17(15), 2102; https://doi.org/10.3390/polym17152102 - 31 Jul 2025
Viewed by 147
Abstract
Ozone is a powerful destructive agent in the oxidative process of polymer composites. The destructive ability of ozone depends primarily on its concentration, duration of exposure, the type of polymer, and its matrix structure. In this work, nonwoven PLA/NR fibers with natural rubber [...] Read more.
Ozone is a powerful destructive agent in the oxidative process of polymer composites. The destructive ability of ozone depends primarily on its concentration, duration of exposure, the type of polymer, and its matrix structure. In this work, nonwoven PLA/NR fibers with natural rubber contents of 5, 10, and 15 wt.% were obtained, which were then subjected to ozone oxidation for 800 min. The effect of ozone treatment was estimated using various methods of physicochemical analysis. The visual effect was manifested in the form of a change in the color of PLA/NR fibers. The method of differential scanning calorimetry revealed a change in the thermophysical characteristics. The glass transition and cold crystallization temperatures of polylactide shifted toward lower temperatures, and the degree of crystallinity increased. It was found that in PLA/NR fiber samples, the degradation process predominates over the crosslinking process, as an increase in the melt flow rate by 1.5–1.6 times and a decrease in the correlation time determined by the electron paramagnetic resonance method were observed. The IR Fourier method recorded a change in the chemical structure during ozone oxidation. The intensity of the ether bond bands changed, and new bands appeared at 1640 and 1537 cm−1, which corresponded to the formation of –C=C– bonds. Full article
(This article belongs to the Special Issue Natural Degradation of Polymers)
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18 pages, 8192 KiB  
Article
Microstructure, Mechanical Properties, and Tribological Behavior of Friction Stir Lap-Welded Joints Between SiCp/Al–Fe–V–Si Composites and an Al–Si Alloy
by Shunfa Xiao, Pinming Feng, Xiangping Li, Yishan Sun, Haiyang Liu, Jie Teng and Fulin Jiang
Materials 2025, 18(15), 3589; https://doi.org/10.3390/ma18153589 - 30 Jul 2025
Viewed by 267
Abstract
Aluminum matrix composites provide an ideal solution for lightweight brake disks, but conventional casting processes are prone to crack initiation due to inhomogeneous reinforcement dispersion, gas porosity, and inadequate toughness. To break the conventional trade-off between high wear resistance and low toughness of [...] Read more.
Aluminum matrix composites provide an ideal solution for lightweight brake disks, but conventional casting processes are prone to crack initiation due to inhomogeneous reinforcement dispersion, gas porosity, and inadequate toughness. To break the conventional trade-off between high wear resistance and low toughness of brake disks, this study fabricated a bimetallic structure of SiCp/Al–Fe–V–Si aluminum matrix composite and cast ZL101 alloy using friction stir lap welding (FSLW). Then, the microstructural evolution, mechanical properties, and tribological behavior of the FSLW joints were studied by XRD, SEM, TEM, tensile testing, and tribological tests. The results showed that the FSLW process homogenized the distribution of SiC particle reinforcements in the SiCp/Al–Fe–V–Si composites. The Al12(Fe,V)3Si heat-resistant phase was not decomposed or coarsened, and the mechanical properties were maintained. The FSLW process refined the grains of the ZL101 aluminum alloy through recrystallization and fragmented eutectic silicon, improving elongation to 22%. A metallurgical bond formed at the joint interface. Tensile fracture occurred within the ZL101 matrix, demonstrating that the interfacial bond strength exceeded the alloy’s load-bearing capacity. In addition, the composites exhibited significantly enhanced wear resistance after FSLW, with their wear rate reduced by approximately 40% compared to the as-received materials, which was attributed to the homogenized SiC particle distribution and the activation of an oxidative wear mechanism. Full article
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13 pages, 3812 KiB  
Article
Generation of Four-Beam Output in a Bonded Nd:YAG/Cr4+:YAG Laser via Fiber Splitter Pumping
by Qixiu Zhong, Dongdong Meng, Zhanduo Qiao, Wenqi Ge, Tieliang Zhang, Zihang Zhou, Hong Xiao and Zhongwei Fan
Photonics 2025, 12(8), 760; https://doi.org/10.3390/photonics12080760 - 29 Jul 2025
Viewed by 184
Abstract
To address the poor thermal performance and low output efficiency of conventional solid-state microchip lasers, this study proposes and implements a bonded Nd:YAG/Cr4+:YAG laser based on fiber splitter pumping. Experimental results demonstrate that at a 4.02 mJ pump pulse energy and [...] Read more.
To address the poor thermal performance and low output efficiency of conventional solid-state microchip lasers, this study proposes and implements a bonded Nd:YAG/Cr4+:YAG laser based on fiber splitter pumping. Experimental results demonstrate that at a 4.02 mJ pump pulse energy and a 100 Hz repetition rate, the system achieves four linearly polarized output beams with an average pulse energy of 0.964 mJ, a repetition rate of 100 Hz, and an optical-to-optical conversion efficiency of 23.98%. The energy distribution ratios for the upper-left, lower-left, upper-right, and lower-right beams are 22.61%, 24.46%, 25.50%, and 27.43%, with pulse widths of 2.184 ns, 2.193 ns, 2.205 ns, and 2.211 ns, respectively. As the optical axis distance increases, the far-field spot pattern transitions from a single circular profile to four fully separated spots, where the lower-right beam exhibits beam quality factors of Mx2 = 1.181 and My2 = 1.289. Simulations at a 293.15 K coolant temperature and a 4.02 mJ pump energy reveal that split pumping reduces the volume-averaged temperature rise in Nd:YAG by 28.81% compared to single-beam pumping (2.57 K vs. 3.61 K), decreases the peak temperature rise by 66.15% (6.97 K vs. 20.59 K), and suppresses peak-to-peak temperature variation by 78.6% (1.34 K vs. 6.26 K). Compared with existing multi-beam generation methods, the fiber splitter approach offers integrated advantages—including compact size, low cost, high energy utilization, superior beam quality, and elevated damage thresholds—and thus shows promising potential for automotive multi-point ignition, multi-beam single-photon counting LiDAR, and laser-induced breakdown spectroscopy (LIBS) online analysis. Full article
(This article belongs to the Special Issue Laser Technology and Applications)
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