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Background/Objectives: The Achilles tendon is a popular allograft option for anterior cruciate ligament (ACL) reconstruction. Structurally, the tendon is known to have a 90-degree rotational fiber track. Preparation techniques, with this consideration, may influence the strength of the graft. This study aims to assess the tensile strength of a novel Achilles tendon allograft harvest procedure following the rotational fiber track. Methods: Both Achilles tendons were harvested from formalin-embalmed cadavers [(n = 20), male n = 13, female n = 7, average age = 70]. Ten cadavers had the right Achilles as the control and the left Achilles as the fiber track sample; 10 cadavers had the opposing designation. Tensile strength was tested utilizing a Bose machine. An unpaired t-test was used to compare data across groups. Results: The average ultimate load for the control group was 874.17 N, with an average elastic stiffness of 76.01 N/mm. The ultimate load for the fiber track group was 807.84 N, with an average elastic stiffness of 64.75 N/mm. No statistically significant difference (p = 0.21) was determined between the average ultimate loads or elastic loads (p = 0.18) across groups. Conclusions: These data suggest that the rotational fiber track method of Achilles allograft has consistent tensile strength and elastic stiffness as compared to the common harvest procedure. The rotational fiber track method for ACL harvesting is a viable alternative option to the common harvest procedure for usage in an ACL reconstruction. [ABSTRACT FROM AUTHOR]

This study highlights the impact of low amounts of MoS2 quantities on composite performance by examining the effects of ultrasonication exfoliated MoS2 at different loadings (0.1–0.5 wt%) on the mechanical and tribological parameters of epoxy composites. Even at low concentrations, the ultrasonication and exfoliation procedures greatly improve the dispersion of MoS2 in the epoxy matrix, enabling its efficient incorporation into the tribofilm during sliding. Optimum mechanical properties were demonstrated by the MoS2/epoxy composite at 0.3 wt%, including a modulus of elasticity of 0.86 GPa, an ultimate tensile strength of 61.88 MPa, and a hardness of 88.0 Shore D, representing improvements of 61.5%, 35.45%, and 16.21%, respectively. Corresponding tribological tests revealed that high sliding velocity (10 N load, 0.2 m/s) resulted in a 44.07% reduction in the coefficient of friction and an 86.29% reduction in wear rate compared to neat epoxy. The enhanced tribological performance is attributed to the efficient removal and incorporation of MoS2 into the tribofilm, where it acts as a solid lubricant that significantly reduces friction and wear. Even though an ultra-low amount of filler concentration was added to the composite, a unique finding was the high MoS2 content in the tribofilm at higher sliding speeds, enhancing lubrication and wear protection. This study establishes that even ultralow MoS2 content, when uniformly dispersed, can profoundly improve the mechanical and tribological properties of epoxy composites, offering a novel approach to enhancing wear resistance. [ABSTRACT FROM AUTHOR]

Reinforcing thermoset polymers with continuous carbon fiber (CF) tow has emerged as a promising avenue to overcome the thermal and mechanical performance limitations of 3D printed polymeric structures for load-bearing applications. Unlike traditional methods, manufacturing continuous fiber-reinforced composites by 3D printing has the unique capability of locally varying the mechanical properties of the composites. In this study, continuous CF thermoset composite specimens were printed with varying line spacing, resin flow rate, and nozzle sizes. The resin flow rates for different line spacings and nozzle sizes were optimized by topographic analysis. Printed composite mechanical properties were evaluated, and their trends were correlated with the trend of print parameter changes. Results showed that tensile strength and modulus could be altered and improved by ~50% by adjusting the printing process parameters. Higher composite strength and modulus were obtained by shortening the line spacing and nozzle diameter. [ABSTRACT FROM AUTHOR]

The material properties and structural characteristics of ballistic composites are crucial to their ballistic performance. A numerical model of a 1.1 g FSP penetrating a UHMWPE target plate was established in this paper. The numerical results show that the failure process of the body armor target plate primarily involves shear failure, interlayer delamination, and tensile failure. Based on this, further research was conducted on the influence of material properties and structural characteristics on the ballistic limit velocity of the UHMWPE armor plate. Furthermore, the study evaluates the effects of elastic modulus, tensile strength, shear strength, number of layers, and interlayer strength on the ballistic limit velocity of UHMWPE body armor. The findings reveal that the ballistic limit velocity is most sensitive to changes in shear strength, with variation rates ranging from −18% to +11%, showing an approximate positive correlation, while the elastic modulus has the smallest impact on ballistic limit velocity, with variation rates ranging from −2% to +4%. Additionally, appropriate interlayer strength can improve the ballistic limit velocity of the body armor to a certain extent. This study provides theoretical methods and recommendations for optimizing anti-penetration performance of UHMWPE body armor. [ABSTRACT FROM AUTHOR]

Material selection is the main challenge in the drone industry. In this study, hardness, abrasive wear, impact resistance, tensile strength, and durability (frost resistance and accelerated ageing) were identified as important characteristics of drone materials. The additive manufacturing technology was used to produce the drone leg specimens and prototype. The suitability of PETG as a primary filament material in the design of the drone leg was investigated. Nine series were printed with different raster lines (0.1, 0.2 and 0.3 mm) and infill densities (30, 60 and 90%). Printed specimens were annealed in salt and alabaster, as well as immersed in liquid nitrogen. Series with raster line-infill densities of 0.1–30, 0.3–30, 0.1–90 and 0.3–90 were identified as the most interesting ones. Thermally treated specimens had better mechanical and durability properties, and infill density was found to be the most important printing parameter. Specimen annealed in salt with a raster line of 0.1 mm and infill density of 90% had the best results. Since ABS is the most common material used for drone leg production, its properties were compared with the PETG specimen, which showed the best properties. The potential of PETG as an alternative material was proven, while the flexibility, productivity and suitability of the leg drone design were additionally confirmed. [ABSTRACT FROM AUTHOR]

Proteins are important factors affecting the properties of natural rubber. Therefore, investigating the effect of free and bonded proteins on the structure and mechanical properties of the vulcanized crosslinking network of natural rubber would provide a theoretical basis for the production of high mechanical resistance natural rubber. Herein, natural rubbers with different protein contents and types were prepared by high-speed centrifugation. And, the effects on their network structure, vulcanization, tensile strength, tearing strength and dynamic mechanical properties were investigated. The results showed that the reduction in protein content led to the decrement in the entanglement networks, crosslinking density and tensile and tear strengths of the vulcanized natural rubber. Moreover, the bonded proteins had an obvious influence on the vulcanization process, while free proteins played an important role in the crosslink densities. These results reveal that both bonded and free proteins are involved in the vulcanization process and the construction of the vulcanized crosslinking network structure of natural rubber, which enhances the mechanical properties such as the modulus and tensile strength of vulcanized natural rubber. [ABSTRACT FROM AUTHOR]

Nuclear power plants, where steel-plate concrete (SC) structures are commonly adopted, require large-scale components to withstand significant loads, such as those caused by sudden explosions. As a result, SC modular members used in nuclear power plants must have thicker walls filled with concrete compared to standard-sized ones. These large walls also require additional components, such as tie bars and H-shaped steel sections, to reinforce adhesion and resist shear stresses. This study focuses on tie bars placed adjacent to studs and evaluates their influence on the tensile strength of wall structures. To investigate this, we conducted experimental tests using full-scale specimens, including various combinations ranging from single stud to combined stud-tie configurations. Based on the results of these performance tests, we propose a design recommendation for estimating the tensile capacity of SC structures, considering the influence of tie bars. [ABSTRACT FROM AUTHOR]

This study aims to examine the variation in corrosion characteristics and tensile properties of WE43 magnesium alloy in an actual marine atmospheric environment by means of outdoor exposure tests. The macroscopic corrosion morphology, microstructure, and tensile properties were analyzed. The results indicated that WE43 alloy will corrode rapidly during exposure under marine atmospheric environmental conditions, resulting in a loose and porous Mg(OH)2 layer on the surface. The Mg matrix was mainly consumed as an anode, leading to the occurrence of corrosion pits. With the increase in exposure time, both the tensile strength and plasticity of WE43 alloy gradually deteriorated. After exposure for six months, the elongation and area reduction were significantly reduced, with a reduction ratio of more than 50%. After 18 months of exposure, the ultimate strength of the alloy decreased from 359 MPa to 300 MPa. According to an analysis of fractures in the alloy, the corrosion pits on the sample surface were the main reason for the decrease in tensile properties. [ABSTRACT FROM AUTHOR]

The last decade was dominated by a serious problem that now affects all the planet's natural ecosystems: the increasing growth of plastics and microplastics that are difficult to dispose of. One strategy to mitigate this problem is to close the life cycle of one of them—polyethylene terephthalate (PET)—by reusing it within the most common building materials, such as mortars and concretes. The reuse of PET waste as aggregates also allows us to limit the CO2 emissions released during the production of natural aggregates. This paper analyzes the outcomes of many studies carried out on the characteristics of cementitious mixtures reinforced with waste PET material. Many researchers have demonstrated how PET used as reinforcement of mortars and concretes can produce an increase in the mechanical strengths of the corresponding cementitious mixtures without PET. The tensile strength of this resin is higher than that of concrete; so, by combining the two materials it is possible to obtain a mixture with an overall higher tensile strength, resulting in increased flexural strength and reduced cracking. Using an effective size of PET fibers, it is possible to achieve an increase in the ductility and toughness of the cementitious mixture. Several studies reveal that PET reinforcement reduces the density with a consequent decrease in weight and structural loads, while the workability increases using spherical and smoother PET aggregates. [ABSTRACT FROM AUTHOR]

The development of thermoplastic starch (TPS) films is crucial for fabricating sustainable and compostable plastics with desirable mechanical properties. However, traditional design of experiments (DOE) methods used in TPS development are often inefficient. They require extensive time and resources while frequently failing to identify optimal material formulations. As an alternative, adaptive experimental design methods based on Bayesian optimization (BO) principles have been recently proposed to streamline material development by iteratively refining experiments based on prior results. However, most implementations are not suited to manage the heteroscedastic noise inherently present in physical experiments. This work introduces a heteroscedastic Gaussian process (HGP) model within the BO framework to account for varying levels of uncertainty in the data, improve the accuracy of the predictions, and increase the overall experimental efficiency. The aim is to find the optimal TPS film composition that maximizes its elongation at break and tensile strength. To demonstrate the effectiveness of this approach, TPS films were prepared by mixing potato starch, distilled water, glycerol as a plasticizer, and acetic acid as a catalyst. After gelation, the mixture was degassed via centrifugation and molded into films, which were dried at room temperature. Tensile tests were conducted according to ASTM D638 standards. After five iterations and 30 experiments, the films containing 4.5 wt% plasticizer and 2.0 wt% starch exhibited the highest elongation at break (M = 96.7%, SD = 5.6%), while the films with 0.5 wt% plasticizer and 7.0 wt% starch demonstrated the highest tensile strength (M = 2.77 MPa, SD = 1.54 MPa). These results demonstrate the potential of the HGP model within a BO framework to improve material development efficiency and performance in TPS film and other potential material formulations. [ABSTRACT FROM AUTHOR]

The strength of ultra-low carbon maraging stainless steels can be significantly enhanced by precipitating nanoscale intermetallic secondary phases. Retained or reversed austenite in the steel can improve its toughness, which is key to achieving an ideal combination of strength and toughness. Ti and Al are often used as cost-effective strengthening elements in maraging stainless steels but the synergistic toughening and strengthening mechanisms of Ti and Al have not been studied. To investigate the synergistic toughening and strengthening mechanisms of Ti and Al in Co-free maraging stainless steels, this paper focuses on the microstructure and mechanical properties of three alloys: Fe-12Cr-11Ni-1.7Al-0.5Ti (Steel A), Fe-12Cr-11Ni-0.5Ti (Steel B), and Fe-12Cr-11Ni-1.7Al (Steel C). The impact of Ti and Al on the microstructure and mechanical properties was investigated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (TEM), and thermodynamic simulations. The relationship between microstructure, strength, and toughness is also discussed. The results indicated that Steel A, containing both Al and Ti, exhibited the highest strength level after solution treatment at 900 °C, with an ultimate tensile strength reaching 1571 MPa after aging at 540 °C. This is attributed to the simultaneous precipitation of spherical β-NiAl and rod-shaped η-Ni3Ti phases. Steel B, with only Ti, formed a significant amount of Ni-rich reversed austenite during aging, reducing its ultimate tensile strength to 1096 MPa. Steel C, with only Al, showed a high strength–toughness combination, which was achieved by forming dispersive nano-sized intermetallic precipitates of β-NiAl in the martensitic matrix with a slight amount of austenite. It is highlighted that Al has superior toughening and strengthening effects compared to Ti in the alloy system. [ABSTRACT FROM AUTHOR]

The evolution of microstructures and mechanical properties with tempering temperature of a novel 2.5 GPa grade ultra-high strength steel with synergistic precipitation strengthening was investigated. With increasing tempering temperature, the experimental steel initially progressed from ε-carbides to M3C and then to M2C, followed by further coarsening of the M2C carbides and β-NiAl. Concurrently, the martensite matrix gradually decomposed and austenitized. The ultimate tensile strength and yield strength initially increased and subsequently decreased with rising tempering temperature, reaching peak value at 460 and 470 °C, respectively. Conversely, the ductility and toughness initially decreased and then increased with rising tempering temperature, reaching a minimum at 440 °C. The increase in strength was attributed to the secondary hardening effects resulting from carbide evolution and the precipitation of β-NiAl. The subsequent decrease in strength was due to the recovery of martensite and coarsening of precipitates. The decrease in ductility and toughness was linked to the precipitation of M3C, while their subsequent increase was primarily attributed to the dissolution of M3C and an increase in the volume fraction of reverted austenite. The high dislocation density of martensite, the film of reverted austenite, nanoscale M2C carbides, and ultrafine β-NiAl obtained during tempering at 480 °C resulted in the optimal mechanical properties of the experimental steel. The strength contributions from M2C carbides and β-NiAl were 1081 and 597 MPa, respectively. [ABSTRACT FROM AUTHOR]

Residual stresses and anisotropic structures characterize laser powder bed fusion (L-PBF) products due to rapid thermal changes during fabrication, potentially leading to microcracking and lower strength. Post-heat treatments are crucial for enhancing mechanical properties. Numerous dental technology laboratories worldwide are adopting the new technologies but must invest considerable time and resources to refine them for specific requirements. Our research can assist researchers in identifying thermal processes that enhance the mechanical properties of dental Co-Cr alloys. In this study, high cooling rates (quenching) and annealing after quenching were evaluated for L-PBF Co-Cr dental alloys. Cast samples (standard manufacturing method) were tested as a second reference material. Tensile strength, Vickers hardness, microstructure characterization, and phase identification were performed. Significant differences were found among the L-PBF groups and the cast samples. The lowest tensile strength (707 MPa) and hardness (345 HV) were observed for cast Starbond COS. The highest mechanical properties (1389 MPa, 535 HV) were observed for the samples subjected to the water quenching and reheating methods. XRD analysis revealed that the face-centered cubic (FCC) and hexagonal close-packed (HCP) phases are influenced by the composition and heat treatment. Annealing after quenching improved the microstructure homogeneity and increased the HCP content. L-PBF techniques yielded superior mechanical properties compared to traditional casting methods, offering efficiency and precision. Future research should focus on fatigue properties. [ABSTRACT FROM AUTHOR]

Soluble aluminum alloy materials used in underground operational tools are synthesized via a high-temperature smelting process. The microstructure and composition distribution of the alloy were analyzed using X-ray diffraction, metallographic microscopy, and scanning electron microscopy with energy-dispersive X-ray and electron backscatter diffraction techniques. The mechanical properties were evaluated using a universal testing machine and hardness tester, while solubility assessments were conducted in a constant-temperature water bath. This study focuses on the plasticity and dissolution characteristics of Al-Mg-Ga-Sn-In alloys with varying Mg contents. The tensile strength (σb) of the alloy was 181.99 MPa, with an elongation (δ) of 27.49% and cross-sectional shrinkage (φ) of 11.67% at a magnesium content of 3.0 wt.%. Additionally, in the compressive test, the compressive yield strength (σsc) was recorded at 188.32 MPa, while the compression rate (δ) was 27.06% and the section expansion rate (φ) was 138.66%. Furthermore, the alloy demonstrated the ability to dissolve spontaneously in water at 90 °C, exhibiting an average dissolution rate of 1.0 g·h−1cm−2 and a maximum dissolution rate of 3.25 g·h−1cm−2 after 12.0 h. Consequently, this alloy composition not only satisfies the requirements for rapid solubility but also exhibits favorable plasticity, providing a novel reference for the selection of soluble aluminum alloy materials. [ABSTRACT FROM AUTHOR]

Glass Fiber Reinforced Polymer (GFRP) bars are used as reinforcement for structural concrete, especially in cases where corrosion of traditional steel reinforcement is a problem. The tensile strength of these reinforcing bars is the primary characteristic on which the design of concrete members reinforced with GFRP bars relies. Determination of the tensile strength of the bars using a direct tensile test is a time and resource-intensive task and therefore is not routinely conducted for quality control. The tensile strength can also be measured from flexure tests, which are much simpler than direct tensile tests, and use appropriate correlation formulations. In this paper, the applicability of flexure testing for the identification of bars' tensile strength is investigated by conducting and analyzing both 3-point and 4-point flexure testing. The correlation formulations are presented that allow the determination of tensile strength from the modulus of rupture. The Weibull weakest link model and the assumption of the same flaw distribution in tensile and flexure tests is adopted. The results of the 3-point and the 4-point bending are presented and compared. Comparisons are also conducted to select direct tensile test results. The work shows that 3-point and 4-point bending tests provide very similar results, with the difference between the results being 2% to 10%, suggesting both tests can be used for tensile strength determination of GFRP bars. [ABSTRACT FROM AUTHOR]

This work aims to assess the possibility of using packaging industry waste to modify polypropylene products (PPs). The products were made in the form of extruded foil and injected samples. The products were produced using regranulate made of polypropylene cast foil. Maleic anhydride-modified polypropylene (MAPP) and polyolefin elastomer (POE) with a glycidyl ester functional group were used to modify the polypropylene. The samples were produced based on 50% foil waste reground and 50% pure PP. The rheological properties of the blends were assessed using the melt mass flow rate (MFR) technique; thermal properties using the differential scanning calorimetry method (DSC). The products manufactured using the injection molding method were subjected to an analysis of mechanical properties, such as tensile strength and impact strength. Also, in the case of film samples, tensile strength was assessed. Color-change assessments with CIE L*a*b* were carried out for all materials. Injection-molded products based on recycled metallized cast foil showed favorable mechanical properties such as tensile strength (1 MAPP = 26.7 MPa; 2 MAPP = 27.1 MPa), which was higher than the original material (cPP = 20.7 MPa). Also, for the films produced from regrind, the tensile strength was at a level similar (1 MAPP = 24.6 MPa; 2 MAPP/POE = 25.1 MPa) to the films extruded from virgin materials (cPP = 24.9 MPa). The introduction of a POE additive to the blends resulted in increased impact strength (1 MAPP/POE = 31 kJ/mol; 2MAPP/POE = 18 kJ/mol; 3 MAPP/POE = 11 kJ/mol) in relation to unmodified samples (cPP = 7 kJ/mol). The introduction of a POE additive to the tested mixtures improved the impact strength of the injected products by almost 4 times for sample 1 MAPP/POE and 2.5 times for sample 2 MAPP/POE in comparison to virgin cPP. These studies confirmed that foil waste can be successfully used to modify polypropylene products shaped both in the injection and extrusion processes. [ABSTRACT FROM AUTHOR]

Owing to its enhanced production efficiency, roller hemming has become the mainstream process for forming and joining metal sheets in the automotive industry. This study investigates the roller hemming process of a specific car door panel through a combination of experimental analysis and finite element analysis (FEA) on both straight-edge and curved-edge flat surfaces. Consequently, the mechanical properties of the door panel, including tensile strength, yield strength, modulus of elasticity, and Poisson's ratio, were estimated through tensile testing and then underwent finite element modeling. The simulation results demonstrated the varying distribution of stress during the rolling hemming process, with the highest stress concentration observed in the bending area. Additionally, creepage and growing results were acquired from both simulation and experimental data to validate the precision of the numerical model. A comparison was made between the experimental and simulation results of the external forces exerted by the roller on the panel. In both straight- and curved-edge sections, the external force during final hemming exceeded that during pre-hemming, as revealed by experimental measurements of both normal and tangential external forces, surpassing their corresponding simulated values. [ABSTRACT FROM AUTHOR]

The use of seashells as a partial substitute for cement in construction not only offers an innovative solution for marine waste management but also contributes to reducing the carbon footprint of the cement industry, decreasing the CO2 emissions associated with cement production and promoting more sustainable construction practices. This study addresses the mechanical behavior of mortar specimens with partial cement replacement using crushed Biobío region clam shells, both calcined and uncalcined, at substitution rates of 5% and 10%. This approach allows the analysis of their effect on the mechanical strength and properties of the mortar, which has not been widely investigated in the Chilean context or with this particular species of shell. For the mechanical characterization of the specimens, tensile flexural tests and compressive tests were were conducted at ages of 3, 7, 14, and 28 days. The compressive strengths of the samples that incorporated calcined residue with partial cement replacements of 5% and 10% were 83.69% and 78.27%, respectively, of the average strength of 20.97 MPa reached by the standard sample. In terms of their tensile flexural strength, these samples reached average strengths of 104.31% and 104.04% of the strength of 12.12 MPa obtained by the standard sample. In the case of the uncalcined samples, the 5% and 10% replacements reached 103.55% and 102.64% of the tensile strength of 15.54 MPa obtained by the standard sample, while they reached 92.32% and 80.07% of the compressive strength of 27.81 MPa achieved by the standard sample. From these results, it is determined that the calcined shells did not improve the mechanical resistance of the mortar, suggesting that the calcination process must be studied in depth. [ABSTRACT FROM AUTHOR]

(1) Background: Dental glass–ceramics shrink during crystallization, complicating restoration manufacturing. Thermo-pressure molding was introduced to address this, with lithium disilicate crystals providing high strength. Residual tensile stresses can influence the chipping strength of single tooth crowns. (2) Methods: Insync dentine was layered onto three lithia-based disilicate core ceramics (Amber Press, IPS e.max Press) for microtensile bond strength tests. The Vickers test assessed the residual tensile stress and interfacial bonding. Porcelain-veneered posterior ceramic crowns were fabricated and subjected to axial loading, measuring fracture loads (three per group). (3) Results: A chemical bonding layer formed at the interface, which was thicker in the Insync-IPS e.max Press and increased with more firings. The ultimate tensile bond strength was 28.5 MPa for the four-times-fired Insync-Amber Press, similar to the twice-fired Insync-IPS e.max Press. No residual tensile stress was found in the Insync-Amber Press; the Insync-IPS e.max Press showed crack growth within 250 μm of the bonded interface. The average fracture resistance was twice as high for the Insync-Amber Press. (4) Conclusions: The Insync-Amber Press exhibited better thermal harmony with no crack growth, while the IPS e.max Press showed crack growth due to residual tensile stress. Insync-Amber Press posterior ceramic crowns had significantly greater fracture resistance than Insync-IPS e.max Press crowns. [ABSTRACT FROM AUTHOR]

The spiral case plays a role in providing stable and uniform water flow in the pump-turbine unit, and the overall structure with the surrounding concrete is an important foundation for the safe and stable operation of the unit and power plant. In order to clarify the comprehensive bearing capacity of preloading steel spiral case under pump operating conditions, this study is based on the theory of the fluid–structure coupling and contact model and uses ANSYS CFX 2021 R1 and mechanical to analyze the flow fluctuation characteristics and dynamic structural response of a preloading steel spiral case and surrounding concrete under different preloading pressures in the intermediate head pump condition. The results indicate that the main frequency of pressure fluctuations inside the main frequency ( 1   f n ) of pressure fluctuations inside the spiral case is influenced by the unstable flow. The contact state between the preloading steel spiral case and concrete is closely related to the relative magnitude of preloading pressure and hydraulic pressure. Higher preloading pressure can lead to an increase in initial preloading clearance, resulting in a decrease in contact area. The vortex motion inside the spiral case is the main factor affecting the distribution of deformation. The rotor–stator interaction also has a certain impact on the vibration of the spiral case structure, even though the influence of rotor–stator interaction on pressure fluctuation inside the spiral case is already small. The monitoring points where the maximum values of static stress and dynamic stress are located are different. Increasing the preloading pressure value does not always guarantee the safety of concrete structures, as the sticking contact area in early contact transfers most of the stress of the spiral case, resulting in significant stress concentration. Under the working conditions of this study, the concrete in contact with the inner edge and nose vane is subjected to excessive loads. Therefore, it is necessary to reinforce the structure with steel bars or other methods to improve its tensile strength. A minimum preloading pressure value of 3.2 MPa is beneficial for reducing the risk of concrete cracking. The research results can provide a deeper understanding of the behavior of preloading steel spiral cases under pump conditions and guide optimization design. [ABSTRACT FROM AUTHOR]

The root systems of vegetation significantly contribute to enhancing slope stability. The shear strength of soil–root systems is a crucial parameter for assessing slope stability. This study focuses on six types of vegetation in the Yellow River Basin of China (woodland: Populus przewalskii and Broussonetia papyrifera; shrubland: Periploca sepium and Ziziphus jujuba; grassland: Artemisia hedinii and Setaria viridis), employing in situ shear tests and the Wu–Waldron model (Wu model) to investigate the shear strength of soil–root systems. The results show that the shear stress–displacement curves for P. przewalskii, B. papyrifera, and Z. jujuba are higher and steeper, with clear inflection points. The tensile strength of the roots from the six vegetation types decreases as the root diameter increases. According to the Wu model, the additional root cohesion is ranked as follows: A. hedinii > B. papyrifera > P. przewalskii > Z. jujuba > P. sepium > S. viridis. Based on the in situ shear tests, the shear strength increments are ranked as follows: Z. jujuba > B. papyrifera > P. przewalskii > A. hedinii > P. sepium > S. viridis. Overall, the additional root cohesion obtained by the Wu model in each soil layer is greater than the shear strength increment measured from the in situ shear tests. In the 0–30 cm soil layers, the soil–root systems of Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii exhibit a better shear strength, whereas P. sepium and S. viridis perform poorly. A principal component analysis reveals that the shear strength of the soil–root systems of different vegetation types is primarily influenced by the soil moisture content and root mass density. Z. jujuba, B. papyrifera, P. przewalskii, and A. hedinii are recommended for ecological restoration projects in the Yellow River Basin of China. [ABSTRACT FROM AUTHOR]

The condensation reactions of 4,4′-(ethane-1,2-diylbis (oxy)) bis(3-methoxybenzaldehyde) (VV) with cystamine, 1,6-hexamenthylene diamine, and a dimer diamine (PriamineTM 1075) produced three types of vanillin-derived imine-and disulfide-containing diamines (VC, VH, and VD, respectively). Thermal curing reactions of polyglycerol polyglycidyl ether with VD and mixtures of VC/VD and VH/VD produced bio-based epoxy vitrimers (BEV-VD, BEV-VC/VD, and BEV-VH/VD, respectively). The degree of swelling and gel fraction tests revealed the formation of a network structure, and the crosslinking density increased with a decreasing VD fraction. The glass transition temperature, tensile strength, and tensile modulus of the cured films increased as the VD fraction decreased. In contrast, the thermal degradation temperature of the cured films increased as the VD fraction increased. All the cured films were healed by hot pressing at 120 °C for 2 h under 1 MPa at least three times. The healing efficiencies, based on tensile strength after the first healing treatment, were 75–78%, which gradually decreased as the healing cycle was repeated. When imine-and disulfide-containing BEV-VC/VD and imine-containing BEV-VH/VD with the same VC/VD and VH/VD ratios were used, the former exhibited a slightly higher healing efficiency. [ABSTRACT FROM AUTHOR]

Zinc-ion batteries (ZIBs) emerge as leading candidates for a flexible energy storage system, distinguished by high capacity, affordability, and inherent safety. The integration of hydrogel electrolytes, particularly those with saturated aqueous solvents, has significantly enhanced the electrochemical performance of ZIBs while preserving their essential flexibility. Nonetheless, challenges in electrochemical performance under specific conditions highlight the nascent stage of this technology, with numerous technical hurdles awaiting resolution. Addressing these challenges, recent investigations have leveraged the unique properties of cellulose hydrogel—namely, its exceptional toughness, tensile strength, extreme temperature resilience, stimulus responsiveness, and self-healing capabilities—to innovate multifunctional flexible zinc-based batteries. This paper conducts a comprehensive review of the physicochemical attributes of cellulose hydrogel electrolytes within ZIBs. We thoroughly analyze their performance under diverse environmental conditions, offering insights into the current landscape and their future potential. By examining these aspects, we aim to underscore the developmental prospects and the challenges that lie ahead for hydrogel electrolytes in ZIBs, paving the way for further advancement in this promising field. [ABSTRACT FROM AUTHOR]

A key challenge in the utilization of waste polyester fibers (PET fibers) is the development of fiber-reinforced composites with high filler content and the improvement of fiber length retention. Herein, the effects of a two-rotor continuous mixer and a twin-screw extruder on the structure and properties of waste polyester fiber composites were evaluated. The results revealed that the mechanical properties of the composites were improved significantly with increasing fiber content, especially when processed using the twin-rotor continuous mixer. This mixer facilitated the formation of a robust fiber network structure, leading to substantial enhancements in tensile strength, flexural strength, and heat resistance. Specifically, compared to those processed by the twin-screw extruder, with 60 wt% fibers content, the tensile and flexural strengths of specimens processed by the twin-rotor continuous mixer increase by 21% and 13%, respectively. The average fiber length in specimens processed by the twin-rotor continuous mixer was 32% longer than that in specimens processed by the twin-screw extruder, attributable to the lower shear frequency and the higher tensile ratio of the former. This blending technique emerges as an effective strategy, contributing significantly to promoting the development and practical application of waste textile fiber-reinforced polymer composites. [ABSTRACT FROM AUTHOR]

The injection molding process is one of the most widely used methods for polymer processing in mass production. Three critical factors in this process include the type of polymer, injection molding machines, and processing molds. Polypropylene (PP) is a widely used semi-crystalline polymer due to its favorable flow characteristics, including a high melt flow index and the absence of a need for a mold temperature controller. Additionally, PP exhibits good elongation and toughness, making it suitable for applications such as box hinges. However, its tensile strength is a limitation; thus, glass fiber is added to enhance this property. It is important to note that the incorporation of glass fiber increases the viscosity of PP. Multi-cavity molds are commonly employed to achieve cost-effective and efficient mass production. The filling challenges associated with geometrically balanced layouts are well documented in the literature. These issues arise due to the varying shear rates of the melt in the runner. High shear rate melts lead to high melt temperatures, which decrease melt viscosity and facilitate easier flow. Consequently, this results in an imbalanced filling phenomenon. This study examines the impact of runner size, gate size, polymer viscosity, and molding process on the filling imbalanced problem in multi-cavity injection molds. Tensile bar injection molding was performed using conventional injection molding (CIM) and microcellular injection molding (MIM) techniques. The tensile properties of the imbalanced multi-cavity molds were analyzed. Flow length within the cavity served as an indicator of the filling imbalance. Additionally, computer simulations were conducted to assess the shear rate's effect on the runner's melt temperature. The results indicated that small runner and gate sizes exacerbate the filling imbalance. Conversely, glass fiber-filled polymer composites also contribute to increased filling imbalance. However, foamed polymers can mitigate the filling imbalance phenomenon. [ABSTRACT FROM AUTHOR]

The dispersion of silica in rubber systems and its interaction with rubber are two key factors in the preparation of rubber composites with excellent properties. In view of this, silica modified with terminal isocyanate-based polybutadiene liquid rubber (ITPB) is used to improve the dispersion effect of silica in rubber and enhance its interaction with the rubber matrix to improve the rubber's performance. The impact of different modification conditions on the dispersion of silica and the properties of modified silica-filled rubber composites were studied by changing the amount of ITPB and the modification method of silica, including blending and chemical grafting. The experimental results show that ITPB is successfully grafted onto silica, and the use of modified silica improves the cross-linking density of rubber, promotes the rate of rubber vulcanization, and overcomes the shortcomings of the delayed vulcanization of silica itself. When the ratio of ITPB liquid rubber to silica equals 1:20, the comprehensive performance of rubber is the best, the ITPB-modified silica has a better dispersion effect in rubber, and the rolling resistance is slightly improved, with tensile strength reaching 12.6 MPa. The material demonstrates excellent overall performance and holds promise for applications in the rail, automotive, and electrical fields. [ABSTRACT FROM AUTHOR]

Cyano-functionalized graphitic nanoplatelets (CyGNs) are synthesized by means of a mechanochemical reaction between graphite and acrylonitrile. The resulting CyGNs exhibit excellent mechanical properties and are highly dispersible in various solvents (i.e., THF). Due to their chemical compatibility (specifically, cyano functional groups), the CyGNs serve effectively as a reinforcing filler for acrylonitrile butadiene styrene (ABS) resin. Consequently, compared to pure ABS, CyGN&ABS-X demonstrates improved mechanical properties and better thermal stability. Notably, the CyGN&ABS-1 specimen exhibits significant enhancements in the tensile strength (26 ± 1 MPa), Young's modulus (992 ± 71 MPa), and tensile toughness (22 ± 3 MPa), representing increases of approximately 130.6%, 19.2%, and 59.6%, respectively, over pure ABS. This underscores the ability of a mechanochemical reaction to directly modify the functional groups of graphitic nanoplatelets (GnPs) as fillers, facilitating their strong compatibility with a variety of polymers, including copolymers. [ABSTRACT FROM AUTHOR]

This study investigates the degradation of six different types of absorbable surgical threads commonly used in clinical practice, focusing on their response to exposure to physiological fluids. The threads were subjected to hydrolytic and enzymatic degradation in physiological saline, bile, and pancreatic juice. Our findings demonstrate that bile and pancreatic juice, particularly when contaminated with bacterial strains such as Escherichia coli, Klebsiella spp., and Enterococcus faecalis, significantly accelerate the degradation process. Using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and tensile strength testing, we observed distinct differences in the chemical structure and mechanical integrity of the sutures. Principal component analysis (PCA) of the FTIR spectra revealed that PDS threads exhibited the highest resistance to degradation, maintaining their mechanical properties for a longer duration compared with Monocryl and Vicryl. These results highlight the critical role of thread selection in gastrointestinal surgeries, where prolonged exposure to bile and pancreatic juice can compromise the suture integrity and lead to postoperative complications. The insights gained from this study will contribute to improving the selection and application of absorbable threads in clinical settings. [ABSTRACT FROM AUTHOR]

Cu alloys have been widely used in the manufacture of liners because of their high density, good plasticity, and excellent thermal conductivity. In order to achieve excellent jet stability and penetration performance, it is necessary to further improve the mechanical properties of Cu-based liners. Nevertheless, the simultaneous enhancement of strength and ductility of the Cu alloys remains a huge challenge due to the strength–ductility trade-off phenomenon of metals/alloys. In this study, the microstructure evolution of rare earth Nd-modified Cu alloy and its effect on mechanical properties were investigated using OM, SEM, EBSD, and TEM techniques. The results show that the ultimate tensile strength (218 MPa) and elongation (50.7%) of sample 1 without Nd are the lowest. With increasing Nd content; the tensile strength and elongation of the samples increase; and the mechanical properties of sample 4 are the best, with a tensile strength of 278.6 MPa and elongation of 65.2%. In addition, with the increase in Nd content, not only is the grain size of the Cu-Nd alloy refined, but also the strength and plasticity are improved so that the strength–ductility trade-off phenomenon is improved. The strength improvement is mainly attributed to grain refinement strengthening, dispersion strengthening, and strain hardening. The increase in ductility is mainly related to the improvement of the microstructure heterogeneity by the Nd element. [ABSTRACT FROM AUTHOR]

To investigate the mechanical properties and microstructure evolution of P92 steel during long-term service, the operated P92 main steam pipes from the first ultra-supercritical units in China were sectioned into samples representing various service durations and stresses (0# (as-received state, 1# (82,000 h, 67.3 MPa), 2# (85,000 h, 78.0 MPa), and 3# (100,000 h, 80.3 MPa)). Thereafter, a comprehensive assessment of their mechanical properties, including tensile strength, impact, hardness, and creep resistance, as well as a detailed microstructure analysis, was carried out. The effect of stress on the aging of material properties during operation is discussed. The results show that the circumferential stress caused by the increase in the internal steam pressure can significantly promote the creep life consumption of P92 steel, resulting in the degradation of mechanical properties and the expedited aging of the microstructure. The Rp0.2 and Rm of the P92 main steam pipe at room temperature and 605 °C decreased with the service time increase, reflecting the influence of stress in operation, which is expected to be used for the residual life evaluation of P92 steel. The relationship between the impact absorption energy (FATT50), Brinell hardness, and the operating time of P92 operating pipes is non-monotonic, indicating that these parameters are not sensitive indicators of material aging due to stress. The evaluation of performance degradation in P92 operating pipes due to stress-induced aging is not reliably discernible through optical metallography alone. To achieve a thorough assessment, the use of transmission electron microscopy (TEM) is essential. [ABSTRACT FROM AUTHOR]

Uniaxial compressive strength (UCS) of rocks is one of the main parameters required in the design of geotechnical projects such as tunnels, dams, or rock slopes. According to the literature, there are a large number of predictive regression equations to evaluate the UCS from the point load index (PLI) and Brazilian tensile strength (BTS). However, the equations developed in previous studies have different accuracies in UCS prediction. A more accurate prediction of the UCS will result in a more appropriate design of the geotechnical project, and thus ensure its success during operation. In the present paper, a comparative study was conducted between the accuracy of PLI and BTS in predicting the UCS of the limestone and sandstone. Moreover, the role of porosity (n) on the accuracy of predicting the UCS from PLI and BTS was investigated. Some statistical indices were used to investigating the accuracy of predictive regression equations of UCS. The results revealed that the UCS of rocks can be predicted with a higher accuracy using BTS compared with PLI. Also, the findings showed that the n had a significant role in increasing the accuracy of PLI- and BTS-based regression equations of the UCS predictive. The predictive equations established in the present study can be used in practical applications for indirect evaluation of limestone and sandstone UCS in the site of a geotechnical project. [ABSTRACT FROM AUTHOR]

In this study, the tensile and bending strength of birch and beech lamellas finger jointed with conventional (Standard) and newly developed finger-joint profiles (New) are presented. Polyurethane (PUR), Melamine-Urea-Formaldehyde (MUF) and Phenol-Resorcinol-Formaldehyde (PRF) adhesive systems were used to bond the finger joints. The objective of the New profiles was to reduce the stress concentrations within the finger joint by cutting the cross-grooved fingers perpendicular to the main orientation of the finger-joint profile. In the first trials of the development, larger cross-grooved fingers were cut with the aim to improve the stress distribution and to reinforce the finger joint by filling gaps in the finger joint with adhesive. As the study progressed, initial optimisations of the New profile were made. Smaller cross-grooved fingers were cut as it was assumed that they are beneficial for the manufacturing and integrity of the New profile. In combination with the MUF adhesive system, the New profile achieved the highest increase in the bending and tensile strengths compared to the Standard profile. In addition to the increased strength, other advantages such as reduced cracking in the finger joint were observed when using the New profile. The high strength and stiffness of hardwoods or other high-performance materials used in timber construction can probably be better exploited in combination with the New profile. Further tests will be carried out by considering different configurations of the New profile and different materials. [ABSTRACT FROM AUTHOR]

The influence of equal channel angular pressing (ECAP) and cyclic extrusion compression (CEC) of Al-1080 on the pressing load, microstructure, and tensile properties was investigated. The pressing peak loads of the CEC were 218.8–265.4% higher than those of the ECAP, with a more complex load behavior in the CEC process. The deformation morphology of the ECAP samples indicates an improvement in the deformation homogeneity with the number of passes. Shear band morphology with a decrease in the shear band width from the center to the outer surface makes up the predominant pattern of the CEC samples. The ECAP samples have 13.9–44% smaller average grain sizes, with 3.8–8.1% higher high-angle grain boundaries (HAGBs) than the CECed samples. The ECAP and CEC processing improve the tensile strength. However, the ECAP sample's tensile strength (UTS) and the proof strength (σ0.2) were 11.5–20.6 and 2.6–16.4% higher than that of CEC, without noticeable differences in elongation. The σ0.2 values were predicted accurately with a deviation range of 1.8–7.3% from the experimental one. The ECAP samples are easy to process under lower loads. Moreover, ECAP samples have an equiaxed grain microstructure with a higher degree of deformation homogeneity and tensile strength. [ABSTRACT FROM AUTHOR]

This article contains an advanced analysis of the properties of solid wire electrical contacts produced by ultrasonic welding, both with and without varnish. The main disadvantage of ultrasonic welding of thin wires is the inability to achieve acceptable peel force and tensile strength, which is mainly due to the deformation and thinning of the wires. This study deals with ultrasonic welding using a ring of thin solid copper wires that minimises the deformation and thinning of the wires. The influence of welding parameters such as energy, pressure and amplitude were systematically analysed. Based on these parameters, the optimum welding programme and control method was determined to weld unvarnished and varnished wires. The investigations included electrical resistance tests, optical microscopy, micro-hardness measurements, peel tests and tensile tests, and the measurement of energy consumption. The results showed no significant differences in microstructure and hardness between varnished and unvarnished joints. Ultrasonic joints of varnished wires achieved lower electrical conductivity (by 38%), lower tensile strength (by 3%) and higher peel strength (by 7%), while the welding process was more sustainable in terms of energy (by 6.6%) and time consumption (without preprocessing). [ABSTRACT FROM AUTHOR]

The study examined the effect of heat treatment parameters of compacted graphite iron (CGI) on the mechanical properties of the material. The microstructure was characterized using optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Three levels of heat treatment parameters were adopted considering the orthogonal test plan 24. The effects of austenitizing temperature and time and austempering on tensile strength, yield strength, and elongation were analyzed. Polynomial regression was chosen because it extends linear regression and allows for modeling more complex, nonlinear relationships between variables. Total regression models were determined for each dataset. The models for tensile strength (Rm) had an approximately 82% coefficient of determination, for yield strength (R0.2) around 50%, and for elongation (A5) around 80%. For optimization, the response surface method (RSM) was used. The results obtained were compared with the proposed mathematical models. The ANOVO results showed that austempering temperature (Tpi) had the greatest effect on each parameter studied. The optimal conditions for the analyzed parameters, assuming tensile strength and yield strength at the maximum level and an elongation of about 0.7%, are obtained for the following heat treatment parameters: Tγ = 890 °C; Tpi = 290 °C; τγ = 120 min; τpi = 150 min. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the influence of martensite particle size on the formation of stress and strain in microstructures of dual-phase steels. In order to achieve this objective, the 3D representative volume element (RVE) method was utilized. Particle size distributions were obtained from the microstructures of DP600 and DP1000 dual-phase steels as they actually exist. Virtual dual-phase steel microstructures were generated according to the above distribution and subsequent validation analyses were performed. In the subsequent phase, microstructures of varying martensite particle sizes (1 µm, 1.98 µm, 3 µm for DP600 and 1.15 µm, 2 µm, 3 µm for DP1000) were formed, and the effects of particle size on deformation behavior under tensile loads were determined. The findings indicated that an increase in martensite particle size resulted in a reduction in tensile strength, accompanied by an increase in deformation amount. [ABSTRACT FROM AUTHOR]

Rare-earth magnesium alloys exhibit higher comprehensive mechanical properties compared to other series of magnesium alloys, effectively expanding their applications in aerospace, weapons, and other fields. In this work, the tensile strength, yield strength, and elongation of a Mg-Gd-Y-Zn-Zr rare-earth magnesium alloy under different process conditions were determined, and a large number of microstructure observations and analyses were carried out for the tensile specimens; a prediction model of the corresponding mechanical properties was established by using a convolutional neural network (CNN), in which the metallographic diagram of the rare-earth magnesium alloy was taken as the input, and the corresponding tensile strength, yield strength, elongation, and three mechanical properties were taken as the output. The stochastic gradient descent (SGD) algorithm was used for parameter optimization and experimental validation, and the results showed that the average relative errors of the tensile strength and yield strength prediction results were 1.90% and 3.14%, respectively, which were smaller than the expected error of 5%. [ABSTRACT FROM AUTHOR]

Aluminium metal matrix composites are widely used in automotive, aerospace, marine, and structural engineering due to their high strength-to-weight ratio and superior mechanical properties. Optimizing friction stir process parameters is critical to enhancing the performance of these materials. This study investigates the effects of FSP parameters such as rotational speed, tilt angle, and traverse speed, on the mechanical properties of AA5083/Silicon carbide and AA5083/Coal composites. Using a Taguchi L9 design of experiments, signal-to-noise ratio, and analysis of variance, this study identifies the optimal process settings for maximizing ultimate tensile strength, microhardness, and elongation. From the results, the study revealed that for AA5083/Silicon carbide composites, rotational speed was the most significant factor affecting tensile strength, while for AA5083/Coal composites, tilt angle played a more critical role. Rotational speed consistently influenced microhardness and elongation for both materials. The signal-to-noise ratio analysis indicates that optimal FSP parameters vary depending on the reinforcement material used. This study highlights the importance of tailoring FSP settings to specific reinforcements to achieve optimal mechanical properties. These findings contribute to the advancement of friction stir processing techniques for fabricating high-performance aluminium metal matrix composites, particularly for applications in industries requiring strong, lightweight, and corrosion-resistant materials. [ABSTRACT FROM AUTHOR]

This study focuses on the petrographic and geomechanical properties of the Inzari Formation rocks in Tar Khel Village, District Swabi, Khyber Pakhtunkhwa, Pakistan, on their suitability as building materials for structures such as bridges, buildings, and roads. Five fresh samples from various areas of this formation were analyzed and identified as siliciclastic mudstone through petrographic analysis. The results of physical properties (water absorption, specific gravity, and porosity) and mechanical properties (unconfined compression strength, unconfined tensile strength, Schmidt hammer test, and shear strength) indicate the Inzari Formation rocks have unconfined compressive strengths ranging from 23 to 94 MPa, specific gravity values ≥2.78, and low porosity and water absorption values (<1%), suggesting their excellent potential as building materials. Comparatively, the unconfined compressive strength values of the Inzari Formation rocks are similar to those of the NikanaiGhar limestone, which averaged 93.348 MPa, further confirming their suitability for construction. Additionally, the low porosity values of the Inzari Formation rocks align with the porosity range of 0.31% to 0.41% reported in the NikanaiGhar limestone study. Based on these findings, the Inzari Formation rocks are appropriate for use as fine aggregate in concrete, asphalt, and other construction materials. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop an artificial neural network (ANN) model for predicting the tensile strength of friction stir welding (FSW) joints between dissimilar materials, with a particular focus on aluminum and copper, using cryogenic processes. The research addresses the challenges posed by differences in material properties and the complex nature of FSW, where traditional experimental methods are time-consuming and costly. FSW experiments were conducted under a variety of conditions, and the resulting temperature data were utilized as input for a heat transfer analysis. The maximum temperature and temperature gradient obtained from the analysis were employed as input variables for training the ANN. The ANN was optimized using the Hyperband tuner and validated against experimental results. The model successfully predicted tensile strength with an average error of 5.4%, demonstrating its potential for predicting mechanical properties under different welding conditions. This approach offers a more efficient and accurate method for optimizing FSW processes. [ABSTRACT FROM AUTHOR]

In port dock engineering, high-piled wharves represent one of the primary structural forms. Damage to the foundation piles is a common issue, influenced by external loads such as impact forces during vessel berthing, slope deformations, and operational loads. This study focuses on the Jungong Road Wharf in Shanghai, utilizing FLAC 3D version 6.0 to conduct dynamic calculations under ship impact loading. The dynamic responses of the structure were analyzed, and various internal forces were extracted during the impact event. By combining concrete cracking failure criteria and fatigue damage theories, the effects of ship collisions on the cracking damage of high-piled wharf structures under different scenarios were assessed. Additionally, the applicability of modal flexibility in high-piled wharf scenarios was evaluated through finite element simulations. The results indicate that the dynamic amplification factor caused by dynamic loading is approximately 1.5, underscoring the necessity of considering this effect in the design and impact analysis of high-piled wharves. The impact loading significantly influences the bending moments of the piles, with inclined piles showing the greatest sensitivity. When a designed ship model collides with the high-piled wharf structure at a speed of 0.2 m/s, the tensile stress in the inclined piles reaches 87% of the ultimate tensile strength of the reinforcement. The impact loading has a relatively minor effect on the axial forces of the piles, a limited influence on the bending moments of the beams, but a considerable impact on the axial forces of the beams. Berthing by oversized vessels and unexpected incidents can lead to more severe damage to high-piled wharf structures. In the finite element simulations, modal flexibility effectively identified the locations of damage, with greater changes in modal flexibility correlating with increased damage severity. [ABSTRACT FROM AUTHOR]

Background/Objectives: An early accelerated rehabilitation is generally recommended after surgery for acute Achilles tendon ruptures (ATRs). The modified side-locking loop suture (MSLLS) is a surgical technique that provides high tensile strength to the repaired Achilles tendon and allows for a safe, early accelerated rehabilitation protocol without requiring postoperative immobilization. However, there are no reports investigating the clinical outcomes of the MSLLS technique with early accelerated rehabilitation for ATRs. To clarify the effectiveness of the MSLLS technique with an early accelerated rehabilitation protocol for ATR in athletes. Methods: We retrospectively analyzed 27 athletes (Tegner activity score ≥ 6) who underwent surgical treatment using the MSLLS technique for ATR between April 2017 and August 2022. All patients underwent an early accelerated rehabilitation protocol without immobilization. Outcome measures included the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot Scale (AOFAS) score taken preoperatively and one year postoperatively, the time required to perform 20 continuous double-leg heel raises (DHR) and single-leg heel raises (SHR), the time to return to the original sport, and the presence of any complications. Results: The mean AOFAS score significantly improved from 37.2 ± 9.7 preoperatively to 96.3 ± 5.3 one year postoperatively. The mean time to be able to perform 20 continuous DHR and SHR was 7.7 ± 1.2 weeks and 11.3 ± 1.6 weeks, respectively. All patients were able to return to their original sport at their pre-injury level in an average of 22.7 ± 3.7 weeks without complication. Conclusions: The MSLLS technique in conjunction with an early accelerated rehabilitation protocol for ATR in athletes produced satisfactory results, with all patients able to return to their original sport at their preinjury level without complication. [ABSTRACT FROM AUTHOR]

The utilization of biowaste fillers in the development of high-density polyurethane (PU) foams has gained significant attention due to environmental and economic benefits. This study investigates the mechanical properties of PU foams reinforced with biowaste fillers extracted from fish scales (FS) and fish scale-derived collagen (FSC). The fish scales and collagen were characterized for their composition and integrated into PU foams at various loadings. Mechanical properties such as tensile strength, hardness, and density were evaluated. ANOVA was used to analyze the mean values. Bonferroni tests were used to identify differences between the filler materials (α = 0.05). The tensile strength increases with an increase in filler content for both FS (59.48 Kpa) and FSC (65.43 Kpa). No differences were observed between FS and FSC in tensile strength. Significant differences were observed between the FS and FSC in both hardness and density (p < 0.001). The results demonstrated that both fillers enhanced the mechanical properties of PU foams, with collagen-reinforced foams showing superior performance. This suggests that collagen and fish scales can be effective biowaste fillers for developing environmentally friendly PU foams with enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

In large format additive manufacturing (LFAM), a keener understanding of the relationship between the manufacture method and material temperature dependency is needed for the production of large polymer parts. Statistical analyses supported by material properties and a meso-structural understanding of LFAM are applied to elucidate tensile data trends. The data from LFAM polyethylene terephthalate glycol with 30% carbon fiber (CF) (PETG CF30%) panels (diagonal, horizontal, and vertical in the x-y print plane) and injection-molded specimens tensile tested at six different testing temperatures (room temperature, 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C) were used for statistical analyses. A standard deviation, a coefficient of variation, and a two-way and one-way analyses of variance (ANOVA) were conducted. The manufacturing method (44.2%) and temperature (47.4%) have a strong effect on the ultimate tensile strength, in which temperature (82.6%) dominates Young's modulus. To explain the difference between the ultimate tensile strength of vertical, diagonal, and horizontal specimens at room temperature, a visual inspection of the specimen failure was conducted and the maximum stress at the crack tip was calculated analytically. The decreased strength in the diagonal specimens resulted from the reliance on interlaminar adhesion strength. Future work will consider the effect of the void space variation on tensile strength variance. [ABSTRACT FROM AUTHOR]

Waterborne polyurethane (WPU) often suffers from poor water resistance and mechanical properties due to hydrophilic emulsifiers. To address these issues, this study introduces glycidyl carbamate (GC) as a crosslinker to improve WPU performance. Three types of GC were synthesized using aliphatic, cycloaliphatic, and aromatic isocyanates, respectively. The crosslinked network was established through a reaction between the epoxide group of GC and the carboxylic acid and amine groups of WPU. Among these, the WPU film utilizing aromatic isocyanate-based GC exhibited the highest crosslink density, modulus, hardness, and water resistance, due to the rigidity of the aromatic molecular structure. However, the film displayed excessive brittleness, resulting in reduced tensile strength, along with yellowing typically associated with aromatic compounds. The WPU crosslinked with cycloaliphatic GC demonstrated the next best mechanical properties and water resistance, with a 2.7-fold increase in tensile strength, a 1.5-fold increase in hardness, and a 66% reduction in the water swelling ratio compared to neat WPU. This study presents a novel and effective strategy to enhance the water resistance and mechanical properties of WPU films, making them suitable for advanced coating applications. [ABSTRACT FROM AUTHOR]

Silica, as a high-quality reinforcing filler, can satisfy the requirements of high-performance green tread rubber with high wet-skid resistance, low rolling resistance, and low heat generation. However, the silica surface contains abundant silicon hydroxyl groups, resulting in a severe aggregation of silica particles in non-polar rubber matrix. Herein, we explored a carbon black (CB)/silica hybrid reinforcing strategy to prepare epoxidized natural rubber (ENR)-based vulcanizates. Benefiting from the reaction and interaction between the epoxy groups on ENR chains and the silicon hydroxyl groups on silica surfaces, the dispersion uniformity of silica in the ENR matrix was significantly enhanced. Meanwhile, the silica can facilitate the dispersity and reinforcing effect of CB particles in the ENR matrix. By optimizing the CB/silica blending ratios, we realized high-performance ENR vulcanizates with simultaneously improved mechanical strength, wear resistance, resilience, anti-aging, and damping properties, as well as reduced heat generation and rolling resistance. For example, compared with ENR vulcanizates with only CB fillers, those with CB/silica hybrid fillers showed ~10% increase in tensile strength, ~20% increase in elongation at break, and ~20% increase in tensile retention rate. These results indicated that the ENR compounds reinforced with CB/silica hybrid fillers are a promising candidate for high-performance green tread rubber materials. [ABSTRACT FROM AUTHOR]

A covalent adaptable network (CAN) of semicrystalline polyolefin blends with triple-shape memory effects was fabricated by the reactive melt blending of maleated polypropylene (mPP) and maleated polyolefin elastomer (mPOE) (50 wt/50 wt) in the presence of a small amount of a tetrafunctional thiol (PETMP) and 1,5,7-triazabicyclo [4,4,0]dec-5-ene (TBD). The polymer blend formed a chemically crosslinked network via the reaction between the thiol group of PETMP and maleic anhydride of both polymers in the blend, which was confirmed by FTIR, the variation of torque during the melt mixing process, a solubility test, and DMA. DSC analysis revealed that the crosslinked polyolefin blends show two distinct crystalline melting transitions corresponding to each component polymer. Improved tensile strength as well as elongation at break were observed in the crosslinked blend as compared to the simple blend, and the mechanical properties were maintained after repeated melt processing. These results suggest that thermoplastic polyolefin blends can be transformed into a high-performance and value-added material with good recyclability and reprocessability. [ABSTRACT FROM AUTHOR]

The processing conditions were varied during the production of polycarbonate-based composites with the multiwalled carbon nanotubes (MWCNTs) Baytubes® C150 P (Bayer MaterialScience AG, Leverkusen, Germany), by melt mixing with an extruder on a laboratory scale. These included the screw design, rotation speed, throughput, feeding position and MWCNT content. Particular attention was paid to the shortening of the MWCNT length as a function of the conditions mentioned. It was found that there is a correlation between the applied specific mechanical energy (SME) during the melt mixing process and MWCNT dispersion, which was quantified by the agglomerate area ratio of the non-dispersed nanotubes based on optical microscopic analysis. The higher the SME value, the lower this ratio, which indicates better dispersion. Above an SME value of about 0.4 kWh/kg, no further improvement in dispersion was achieved. The MWCNT length, as measured by the quantitative analysis of TEM images of the MWCNTs dissolved from the composites, decreased with the SME value down to values of 44% of the original MWCNT length. At a constant loading of 3 wt.%, the tensile strength and tensile modulus were almost independent of the SME, while the elongation at break and notched impact strength showed an increasing trend. The variation in the feeding position showed that feeding the MWCNTs into a side feeder led to slightly better electrical and mechanical properties for both types of MWCNTs studied (Baytubes® C150 P and Nanocyl™ NC7000 (Nanocyl S.A., Sambreville, Belgium)). However, feeding into the hopper led to better CNT dispersion with Baytubes® C150 P, while this was the case with Nanocyl™ NC7000 when feeding into the side feeder. The screw profile had an influence on the dispersion, the MWCNT length and the electrical resistance, but only to a small extent. Distributive screws led to a greater shortening of the MWCNT length than dispersive screws. By varying the MWCNT content, it was shown that a greater MWCNT shortening occurred at higher loadings. Two-stage masterbatch dilution leads to stronger shortening than composite production with direct MWCNT incorporation. [ABSTRACT FROM AUTHOR]

With the rapid development of the automotive industry, the requirements for bodywork materials are not only focused on high strength but also on improved forming properties. To develop a new generation of automotive steels with higher strength–plasticity matching, a high elongation 1200 MPa grade V-Nb microalloyed cold-rolled reinforced formable dual-phase steel was developed in this experiment through rational compositional design and precise process machining. The properties of the test steel are improved by varying the over-aging temperature as well as the annealing temperature to achieve a good strength–plasticity balance. The results show that as the aging temperature increases, the tensile strength and yield strength of the test steel decrease, while the elongation continues to increase. At an aging temperature of 310 °C, the steel exhibits not only high strength but also better ductility. As the annealing temperature increases, the tensile strength and yield strength of the test steel initially increase and then decrease, while the elongation continues to increase. When the heat treatment process involves an annealing temperature of 860 °C and an over-aging temperature of 310 °C, the test steel achieves the best strength–plasticity balance. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of pre-gelation on cellulose dissolved in LiCl/DMAc solutions to enhance the properties of regenerated cellulose materials. This study focuses on characterizing the crystallinity, molecular orientation, and mechanical performance of cellulose fibers and hydrogels prepared with and without pre-gelation treatment. X-ray diffraction (XRD) analysis reveals that crystallinity improvement from 55% in untreated fibers to 59% in fibers pre-gelled for 3 and 7 days, indicating a more ordered arrangement of cellulose chains post-regeneration. Additionally, XRD patterns show improved chain alignment in pre-gelled fibers, as indicated by reduced full width at half the maximum of Azimuthal scans. Mechanical testing demonstrates a 30% increase in tensile strength and a doubling of the compression modulus for pre-gelled fibers compared to untreated fibers. These findings underscore the role of pre-gelation in optimizing cellulose material properties for applications ranging from advanced textiles to biomaterials and sustainable packaging. Future research directions include further exploration of the structural and functional benefits of pre-gelation in cellulose processing and its broader implications in material science and engineering. [ABSTRACT FROM AUTHOR]