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Highlights The potential of polytetrafluoroethylene (PTFE) products as surgical dressings is considerable, yet their absence of antibacterial properties substantially restricts their medical applications. To enhance the utility of PTFE in the medical sector, this research loaded nano zinc oxide (ZnO) particles into the PTFE filament matrix through a wet spinning process. This approach successfully yielded PTFE/ZnO composite filaments with antibacterial properties. The characterization results of the filaments show that when the mass ratio of PTFE to ZnO is 8:1, the filament has the best mechanical performance with a tensile strength of 6.78 MPa and an elongation at break of 274.46%. At the same time, composite antibacterial filaments under different process conditions show excellent antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with an antibacterial rate of over 99%. The excellent mechanical properties ensure the ability to further process single filaments, which can be woven into fabrics, textiles, and various other products. Therefore, the composite antibacterial filaments with excellent comprehensive performance prepared in this study are expected to be applied in the field of medical fabrics. Provide new solution ideas for functional PTFE composite filaments preparation. The prepared PTFE/ZnO composite filament has good acid and alkali resistance as well as excellent antibacterial properties, which is expected to broaden the application field of PTFE filaments. [ABSTRACT FROM AUTHOR]

Natural fiber-reinforced biocomposites offer sustainable alternatives to conventional plastics. This study investigates the development of biocomposites using coconut spathe fiber, a renewable byproduct, reinforced with corn starch and poly(vinyl alcohol). The composites demonstrated significant mechanical properties, including a tensile strength of 46.8 MPa, flexural strength of 42.1 MPa, and an impact strength of 11.2 kJ m−2. Water absorption was limited to 33.6% after 24 hours, indicating hydrolytic stability. Biodegradation tests confirmed the complete breakdown of the material in composting conditions. These findings highlight the potential of coconut spathe-based biocomposites for applications in the automotive and packaging industries, addressing the need for sustainable and biodegradable materials in place of non-degradable thermoplastics. [ABSTRACT FROM AUTHOR]

Six varieties of alkoxy polyhedral oligomeric silsesquioxanes (POSSs) featuring methoxy, ethoxy, n‐propoxy, isopropoxy, n‐butoxy, and n‐hexoxy as terminal groups were synthesized using the direct dehydrogenation condensation method. These POSSs were then incorporated as cross‐linking agents into hydroxy‐terminated polydimethylsiloxane (HPDMS) to create various formulations of room temperature vulcanized silicone rubbers (RTV SRs), denoted as SRM, SRE, SRP, SRI, SRB, and SRH. The morphology, thermal stability, and mechanical properties of the resulting SRs are analyzed using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and universal tensile testing machine. The findings indicate that the incorporation of POSS into SRs results in significant enhancements in thermal stability and mechanical properties when compared to the control group (TEOS/SR). SRB and SRH exhibit the highest cross‐linking density and tensile strength. Specifically, SRB‐4 demonstrates the highest tensile strength at 2.66 MPa, representing an 8.6‐fold increase compared to TEOS/SR. The maximum decomposition rate temperature of SRP‐4 reaches 527°C and is 194°C higher than TEOS/SR. Because the alkoxy groups with different chain lengths on POSS have different chemical reactivity, they have a great effect on the dispersion of POSS in SRs, which affect the cross‐linking density, tensile strength, and thermal stability. [ABSTRACT FROM AUTHOR]

This study investigates the effect of oxidized sucrose (OS) on selected functional properties of cast films from lupin protein isolate (LPI). LPI with a protein content larger than 0.9 g g−1 was obtained by alkaline extraction and isoelectric precipitation from bitter narrow‐leaved lupins (Lupinus angustifolius L.). OS was synthesized by vicinal diol cleavage using sodium periodate and was successfully characterized by Fourier‐transform infrared‐, 1H‐nuclear magnetic resonance spectroscopy, and aldehyde titration. Films were produced from heated (85°C, 30 min), alkaline (pH 10), aqueous solutions of LPI (0.1 mL−1), glycerol (300 mg g−1 of LPI) and OS (25, 50, 75, and 100 mg g−1 of LPI). The effect of covalent crosslinking between OS and protein chains was studied by investigating mechanical properties, moisture content, total soluble matter, water vapor permeability, and protein solubility for all films. LPI films produced with the addition of OS showed increased mechanical performance as the tensile strength was increased from 3.5 up to 9.3 MPa and elongation at break values could be raised from 118% to 176%. Taken together with the facts that these films are thermoformable and show improved wet strength compared with control films, make them promising materials for sustainable packaging and short‐term applications in agriculture and forestry. [ABSTRACT FROM AUTHOR]

Polylactic acid/poly(methyl methacrylate) (PLA/PMMA) composite fibers with high performance were fabricated using melt spinning technique. The crystallization, lamellae orientation and physical properties of composite fibers were investigated systematically. The addition of PMMA (0–20 wt%) has improved the hydrolysis resistance of composite fibers by preventing water molecules from penetrating and diffusing through the fibers, but the strength and heat resistance were reduced at the same time. The stereocomplex crystallites (SC) formed before spinning by introducing poly(D‐lactide) (PDLA) (3 wt%) in poly(L‐lactide) (PLLA) matrix and acted as nucleating agents to enhanced the crystallization and lamellae orientation of PLLA matrix, which improved the physical properties of PLA composite fibers resultful. The tensile strength of PLA fibers with 3 wt% PDLA and 5 wt% PMMA was increased 31% as well as the boiling water shrinkage and the hydrolysis rate were decreased 30% and 33% in relation to PLLA fibers. Finally, the hydrolysis resistance was further enhanced on the basis of realizing high strength and heat resistance, which is of great significance for preparing durable PLA fiber materials and expanding their application. [ABSTRACT FROM AUTHOR]

This study explores the influence of environmental factors and printing orientation on the aging of additive manufactured polyamide 12 (PA12). A multifactorial experimental design was employed to age specimens under controlled conditions. Analysis of variance revealed that temperature, irradiance, relative humidity, and time significantly impact the ultimate tensile strength (UTS) and Young's modulus (Y) of PA12. Applying multiple linear regression methods produced predictive models with R2 values of 0.9075 for the UTS and 0.5226 for the Y, indicating substantial explanatory power for the specimen's UTS. These models enhance understanding of PA12 aging, aiding in the design of more durable mechanical parts for applications exposed to environmental conditions, such as footwear, automotive components, and medical devices. As next steps, future research could empirically deploy these developed predictive models and explore longer time scales to further elucidate the long‐term aging behavior of additively manufactured PA12. [ABSTRACT FROM AUTHOR]

This study provides a systematic investigation of the effects of process parameters and heat treatments on the material properties of AlSi10Mg, produced by laser powder bed fusion (L-PBF). Using a central composite design (CCD) with 106 test specimens (49 cubes, 57 tensile), the samples were studied for key properties: density (up to 99.96%), hardness (up to 154.6 HV1), surface roughness (as low as 1.9 Ra), tensile strength (up to 487.5 MPa), and elongation at break (up to 16.6%). Statistical analysis (ANOVA) identified laser power and scanning speed as the most influential parameters on these properties. Additionally, heat treatment was shown to reduce hardness and tensile strength but increase elongation at break, demonstrating the ability to modify mechanical properties based on the desired outcome. Process parameter optimization yielded properties comparable to some of the highest reported values for AlSi10Mg in the literature. The study also discusses the transferability and reproducibility of L-PBF results across different machines, highlighting challenges related to machine-to-machine variations, lack of calibration and standardization and parameter consistency. The results demonstrate the potential of L-PBF to produce AlSi10Mg parts with tailored properties for industrial applications. [ABSTRACT FROM AUTHOR]

In this study, the effect of ultrasonic vibration during Friction Stir Vibration Processing (FSVP) on the microstructure and mechanical behaviour of AZ31/TiC surface composites was investigated. Specifically, Titanium Carbide (TiC) particles were introduced as a reinforcement (15 vol%) into the magnesium alloy AZ31 using both Friction Stir Processing (FSP) and FSVP. Comprehensive examinations were carried out to analyse the microstructure, hardness, and tensile behaviour of the resulting composites. The study revealed significant improvements in mechanical properties due to the application of ultrasonic vibration during FSP. Firstly, the stir zone region was found to be free from voids, enhancing material flow and promoting even dispersion of TiC powders within the matrix. Secondly, refinement of grains was observed due to dynamic recrystallization and the pinning effect imposed by TiC particles, leading to the formation of more dislocations in the composite and indicating a considerable alteration in the material's structure. Importantly, the vibration during FSP introduced an auxiliary energy source, resulting in a remarkable enhancement in both hardness and tensile strength. Compared to the AZ31/15 vol% TiC FSP composite, the composites produced via FSVP exhibited a grain size reduction of about 64% and improvements in hardness and ultimate tensile strength (UTS) of about 55% and 21%, respectively. Notably, these improvements were achieved without compromising the ductility of the composite, which remained at appreciable levels. [ABSTRACT FROM AUTHOR]

High‐temperature‐withstanding TiO2‐reinforced cyanate ester composites are developed by mechanical stirring, followed by curing at elevated temperatures. The uniform dispersion of the filler is confirmed using scanning electron microscopy and electron dispersive spectroscopy. All composites, up to a filler fraction of 30 vol%, exhibit a density of more than 90% while it reduces significantly after that. A high relative permittivity of 7.6 and a low loss tangent of 0.0112 are observed for the optimally filled 30 vol%. The addition of the filler further improves the temperature‐withstanding capability of the cyanate ester matrix. Moreover, a high thermal conductivity of 0.543 W mK−1, improved hardness of 24.88 HV, ultimate tensile strength of 11.68 MPa, and a low coefficient of thermal expansion of 36.44 ppm °C−1 are also shown by the optimally filled sample. A moisture absorption of 0.072 vol% observed for the optimal filled sample comes within the limit for microwave substrate applications. Thus, the developed composites are suitable candidates for high‐temperature microwave electronic applications. [ABSTRACT FROM AUTHOR]

High performance bolts, made of continuous fiber reinforced silicon carbide composites (C/SiC), are crucial to the design and preparation of the hot-end C/SiC components with large complex structures both in aerospace and aeronautical fields. In this work, in-situ grown SiC whiskers were uniformly introduced into the porous laminated 3DN C/SiC countersunk bolt, in order to improve the brittle nature of the 3DN C/SiC threads. Results showed that 7 % increase of tensile strength of the 3DN C/SiC countersunk bolts was achieved via in-situ grown SiC whiskers, and a fatigue life of 106 cycles was also passed. The stud fracture morphologies indicated that the SiC whiskers grew within the woven pores and toughened the layered SiC matrix, so that the load transfer between the layered SiC matrix and carbon fibers was improved under tension. Further high temperature tests showed that the tensile and the shear strengths of the in-situ toughened 3DN C/SiC countersunk bolts were degraded to 64.74 % and 28.83 % at 1000 °C in air respectively. During the thermal exposure, the carbon fibers were largely consumed by oxidation, while the SiC whiskers grew slender and formed a fluffy layer to partially reinforce the SiC matrix. The synergy effect of SiC whiskers and carbon fibers to hinder crack propagation and to toughen the SiC matrix contributes to the above mechanical properties of the bolts. [ABSTRACT FROM AUTHOR]

Ceramic matrix composites (CMCs) have a wide range of applications in key areas, such as aerospace and defense, and to study the mechanical properties and damage mechanisms of fiber-reinforced CMCs under different tensile conditions. Firstly, an ultrasonic vibration tensile device was designed, based on stress superposition and softening effect, the ontological relationship of materials under ultrasonic vibration-assisted stretching was established to study the damage mechanism of materials under different vibration conditions. The results show that tensile damage has multiple damage mechanisms occurring, i.e., matrix multiple cracking, interfacial debonding, and fiber fracture, and is also the main cause of nonlinear characteristics. Under high-frequency alternating load, the tensile strength decreased by up to 32 MPa, and the strain at break increased by up to 0.24 %; the tensile damage mechanism changed, the interfacial strength of the fiber and matrix decreased, the fiber toughness increased significantly, and the fracture morphology became flatter. [ABSTRACT FROM AUTHOR]

Gelling-fibre dressings have been found to be a rapid and effective tool for exudate management. Suprasorb Liquacel Pro is a soft, conformable non-woven dressing made from sodium carboxymethyl cellulose and strengthening cellulose fibres. When it comes into contact with wound exudate or blood, the absorbent dressing forms a gel, creating a moist wound environment. Cell debris and bacteria in the exudate are retained inside the fibre dressing and removed during the dressing change. The high vertical absorption of exudate into the fibre dressing protects the wound environment and the wound edge, thus supporting the healing process. Suprasorb Liquacel Ag has additional antimicrobial abilities with the inclusion of nanosilver technology, shown to be effective in killing bacteria and managing bioburden. [ABSTRACT FROM AUTHOR]

This study presents the development of a material selection decision support system for an automotive rooftop tent. The system uses five parameters of material cost, formability, corrosion resistance, tensile strength and hardness to optimize material choice from a list of aluminium alloy options. This was done before production via the deep drawing process can commence. The parameters were quantified using the average market prices for each alloy, product requirements obtained from the case study and the performance data that was obtained from the uniaxial tensile and hardness tests. These inputs were combined with the developed material selection framework and then programmed into a web-based decision support system for automated, data-driven material selection. The output presents the recommendation for the optimum material that balances cost-effectiveness and performance. The decision support system was successfully used to select the optimum alloy for the rooftop tent. Results show that AA1050 is the optimum material, providing weight reduction at the minimum achievable cost without compromising the product requirements for the rooftop tent. The decision support system is also scalable, and this allows it to be used with larger datasets for different products and processes in the future. [ABSTRACT FROM AUTHOR]

Background: Using infection control barriers (ICBs) on light curing units (LCUs) became mandatory to achieve proper infection control measures without jeopardizing the integrity of the restorations, especially at deeper layers. This study explored the effect of two ICBs on the irradiance of the LCU, as well as the degree of conversion (DC) and flexural strength (FS) of two types of bulk-fill composites. Water vapor permeability (WVP) of both barriers was also assessed to evaluate the capability of such barriers to prevent transmission of blood and saliva droplets and aerosols. Methods: Two bulk-fill composites (X-tra fil and Tetric N- ceram) and two ICBs (Pinnacle Cure sleeve and Sanita wrapping film) were used in this study. Light irradiance was recorded per experimental condition using spectroradiometer. For DC and FS, specimens of 4 mm thickness were prepared. Each specimen was composed of two separable upper and lower layers of thickness 2 mm. DC and FS were measured using Infra-red spectroscopy and three-point loading test respectively. WVP was investigated using the cup method. Means and standard deviations were calculated, and the data were statistically analyzed using factorial analysis of variance test (α = 0.05). Results: Light irradiance showed highest values using no ICBs and lowest values using Pinnacle curing sleeve. Both bulk-fill composites showed higher DC mean values without ICBs and when using Sanita wrapping film for both upper and lower layers of the specimens compared to Pinnacle curing sleeve. The upper layers of composite specimens showed higher DC compared to lower layers for all experimental conditions. Both ICBs had no adverse effect on FS of both composites' upper layers. Pinnacle sleeve significantly reduced FS of both composites' lower layers. X-tra fil showed higher DC and FS compared to Tetric N-Ceram for all experimental conditions. Regarding WVP; the wrapping film showed higher WVP compared to the curing sleeve. Conclusions: Sanita wrapping film can be used as a successful ICB, without jeopardizing the concept of bulk-fill composites. Pinnacle cure sleeve can be considered an effective ICB, however its influence on properties and serviceability of bulk-fill composites remains questionable. [ABSTRACT FROM AUTHOR]

In this paper, a series of silicon hybrid polyurethane‐imides (SPUI) with high stability were constructed by introducing diphenylsilanediol (DPSD) and imidization effect, in which the segment character and hydrogen bonding were adjusted. Various "sea‐island" microphase separations, similar evolution from blooming flower to bud like microdomains was originating from the hard segment clusters, where the segment distribution was labeled and visualized by the stacking of silicon heteroatom. Comparing with pure polyurethane (PU), tensile strength and elongation at break for SPUIs increased from 0.71 ± 0.04 to 17.67 ± 1.84 MPa and from 84.39% ± 6.79% to 202.38% ± 14.50%, respectively. Interestingly, the silicon‐induced aggregates of hard segments in SPUI/graphite flakes (SPUI/GFs), densely crowded around GFs except for some dispersions, revealing similar coupling agent characters of SPUI and self‐affinity with GFs. Thus, the high performance was achieved due to adjustable percolation and cross‐linking networks. Percolation thresholds were decreased from 2.04 to 0.61 wt% and the conductivity of 1.0 × 100 S/m at GFs contents of 5.0 wt% for SPUIz/GFs‐500 was achieved, 2–3 orders of magnitude higher than that of SPUIz/GFs‐2000 except for high stability in conductivity, far lower than those of reported composites. Finally, this study was of great significance for developing functional PU materials with high performance. [ABSTRACT FROM AUTHOR]

This paper proposes an innovative multi-scale method for determining gas pressure parameters of superplastic forming, which is based on the quantitative relationship between the grain growth mechanism and fracture mechanism of Tie6Ale4V alloy. The high-temperature tensile tests were conducted on the material at temperatures ranging from 700, 800, 840, 890, 920, and 950 °C, strain rates were selected as 10-2~10-4/s. The grain size measurements were observed using electron back-scatter diffraction (EBSD). Particularly, the relation between grain size changes and fracture behaviour is specifically discovered using a physically-based dynamic material model (DMM), and the grain size thresholds for each forming limit are proposed. The physical fracture mechanism is named the "Grain growth based fracture (GGBF)" mechanism. Furthermore, an innovative method based on the GGBF mechanism is proposed to design the superplastic forming loading, and practical four-layer hollow structures experiments are applied to validate the fracture mechanism in superplastic forming. In total, A superplastic forming GGBF mechanism has been verified, and it is expected to be helpful for shape and property control in the forming process of complex structures. [ABSTRACT FROM AUTHOR]

A study was carried out to investigate and enhance the effects of friction stir welding on the mechanical characteristics of a flange composed of 6061-T3 aluminum alloy. The pipes possess an outer diameter and wall thickness of 6 mm, while the plates are sized at 100 x 100 × 6 mm. Nine unique experiments were planned using the Taguchi orthogonal array method, with the welding tool remaining constant. Three independent variables (travel speed, rotation speed, and shoulder diameter) were altered at three different levels for each variable. The research analyzed the influence of various FSW factors on the weld flange joint. Analysis of variance (ANOVA) and grey relational analysis (GRA) were employed to determine the impact of each FSW underwater parameter. Moreover, the statistical Taguchi technique (TM) was used to predict the optimal combination of welding parameters to improve tensile properties, including tensile strength (UTS), yield strength (YS), elongation (EI%), and bending load (BL) of welded joints. Additionally, the actual tests demonstrated a high level of agreement with the results obtained from the proposed mathematical model. The validation results obtained indicate that the optimization method is a dependable tool for enhancing the quality responses of friction stir welding. [ABSTRACT FROM AUTHOR]

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]

Comminuted proximal humerus fractures are often repaired by metal plates, but potentially still experience bone refracture, bone "stress shielding," screw perforation, delayed healing, and so forth. This "proof of principle" investigation is the initial step towards the design of a new plate using alternative materials to address some of these problems. Finite element modeling was used to create design graphs for bone stress, plate stress, screw stress, and interfragmentary motion via three different fixations (no, 1, or 2 "kickstand" [KS] screws across the fracture) using a wide range of plate elastic moduli (EP = 5–200 GPa). Well‐known design optimization criteria were used that could minimize bone, plate, and screw failure (i.e., peak stress < ultimate tensile strength), reduce bone "stress shielding" (i.e., bone stress under the new plate ≥ bone stress for an intact humerus, titanium plate, and/or steel plate "control"), and encourage callus growth leading to early healing (i.e., 0.2 mm ≤ axial interfragmentary motion ≤ 1 mm; shear/axial interfragmentary motion ratio <1.6). The findings suggest that a potentially optimal configuration involves the new plate being manufactured from a material with an EP of 5–41.5 GPa with 1 KS screw; but, using no KS screws would cause immediate bone fracture and 2 KS screws would almost certainly lead to delayed healing. A prototype plate might be fabricated using alternative materials suggested for orthopedics and other industries, like fiber‐metal laminates, fiber‐reinforced polymers, metal foams, pure polymers, shape memory alloys, or 3D‐printed porous metals. [ABSTRACT FROM AUTHOR]

As a hydrocarbon reservoir rock, shale is generally composed of highly compacted clay particles with submicrometer sizes and includes nanometric porosity and different hard particles, like quartz, pyrite, etc. One of the key reasons for the formation of a complex fracture network via hydraulic fracturing is the multiscale heterogeneity of shale, especially heterogeneity on the microscale. This paper conducted on an experimental investigation of shale and explored the intrinsic relationship between the microstructure, the related mechanical properties at the micrometer level and the anisotropic failure mechanism. Small-scale specimens with micrometer dimensions in the form of cantilever beams with rectangular cross-section were fabricated by means of a focused ion beam (FIB) and tested via bending with a nanoindenter. The load–deflection curves of these bending beams were monitored up to failure, and the tensile strength of the shale composite was directly derived from the load–deflection curves at 474.5 MPa (parallel to the bedding plane) and 168.9 MPa (vertical to the bedding plane). The results show that the strength anisotropy of shale at the micrometer scale is driven by the clay particles and other minerals, and the bonds of these particles. The modulus anisotropy of the shale composite at the microscale is dominated by the orientation of clay particles. Moreover, the shale composite embedded with pyrite exhibited strong softening characteristics. [ABSTRACT FROM AUTHOR]

Cardiovascular disease, arteriosclerosis, is characterized by the thickening of blood vessel (arteries) walls restricting blood flow and is a global health problem. One treatment option is a surgical procedure utilizing an autologous or synthetic vascular graft to bypass or replace the diseased arterial segment. The goal of this study was to fabricate and mechanically characterize near field electrospun bioresorbable vascular grafts with a fibrous architecture that mimics the arterial extracellular matrix. Polydioxanone vascular constructs with circumferential fiber alignment angles of 15°/75° and 30°/60° (0° representing circumferential fiber alignment) were fabricated using a custom built near-field electrospinning (NFES) system. The vascular construct mechanical properties were compared to the saphenous vein (SV) and internal mammary artery (IMA) through longitudinal and circumferential uniaxial mechanical testing, suture retention, and burst pressure evaluations. The results demonstrated that the 15°/75° templates were closest to mimicking the native vessel target properties as compared to the 30°/60°; however, neither of the vascular template designs achieved or exceeded all the target values. For the ultimate tensile strength, both the constructs met the SV value on the circumferential axis (2.61 MPa) and the IMA value on the longitudinal axis (4.3 MPa). In terms of suture retention, the 15°/75° template was the only construct that was in the IMA and SV targeted range of 138–200 gf. Finally, the burst pressure testing results indicated that neither of the vascular constructs achieved the level of the SV or IMA (1600–3196 mmHg), however, the 15° constructs were within the lower error of the SV. In conclusion, with further design modifications, NFES constructs have demonstrated promise as small-diameter vascular grafts by mimicking native arterial architecture and mechanical properties. [ABSTRACT FROM AUTHOR]

Taking inspiration from diverse interlocking and adhesion structures found in nature, a biaxially interlocking interface is developed in this work. This interface is formed by interconnecting two electrostatically flocked substrates and its mechanical strength is enhanced through the incorporation of enoki‐mushroom‐shaped microfibers and deposited extracellular matrix (ECM). Tips of flocked straight fibers can be transformed into mushroom shapes through thermal treatment. The tensile strength of interlocked scaffolds with mushroom‐shaped tips drastically increases when compared to scaffolds made of straight fibers, which is not reported previously. More cells proliferate within interlocked scaffolds with mushroom‐shaped tips than scaffolds with straight fibers. Additionally, the mechanical strength (e.g., compressive, tensile, and shear) of cell‐seeded interlocked scaffolds increases proportionally to the amount of ECM deposited by dermal fibroblasts. The biaxially interlocking interface developed in this study holds promise for applications in engineering interfacial tissues, modeling tissue interfaces, investigating tissue–tissue interactions, and facilitating tissue bridging or binding. [ABSTRACT FROM AUTHOR]

This study aims to determine and compare the dimensional stability, setting time, tensile strength, and rheological properties of kaolin clay powder-modified and unmodified alginate impression material. Commercially available alginate-based impression material was considered as a control (C) while experimental groups E-1, E-2, and E-3 were fabricated by adding 2%, 4%, and 8% of kaolin clay powder in the control, respectively. Analytical techniques were used for the characterization of the samples. A tensile strength, rheological property, dimensional stability, and setting time were recorded for control and experimental groups. FTIR analysis confirmed the presence of kaolin clay powder in all experimental groups. SEM showed a round solid structure and irregular shape particle appearance in all experimental groups as well as a control group. The dimensional stability was improved by the addition of kaolin clay powder to the alginate impression material. The percentage dimensional change at 5 min, 6, and 12 h was increased for E3 adding (8% kaolin clay powder) and decreased for the control group. The mean value of tensile strength was highest for E3 followed by E2, E1, and least in control groups. Higher Young's Modulus and lower deformation values were measured for E3. The mean value of setting time was highest for E3 and the least was in the control group. The results for both setting time and tensile strength were very highly statistically significant (p < 0.001). The mean values of viscoelasticity, flow, and drip test were increased statistically by adding various concentrations of kaolin clay powder to the alginate impression material. [ABSTRACT FROM AUTHOR]

The U-girder has been applied to the China's Fenghuang Maglev Sightseeing Express for the first time around the world, but mechanical behaviors of the U-girder under different loading conditions have not been investigated comprehensively. Firstly, an elaborate finite element (FE) model of the 25 m U-girder considering the longitudinal prestressing tendons and the detailed track structure is built in the paper, and then an in-situ modal test is conducted to validate the FE model. Furthermore, a coupled dynamic model of maglev train-track-girder system is built by the MTS-DCSP distributed co-simulation platform. Secondly, the stress and deformation of the U-girder under the severe temperature gradient loads are analyzed carefully. The results indicate the maximum stresses always appear near the junction between the floor and the track supporting stands, but they are less than the strength of C55 grade concrete. The temperature-induced deflection on the rail can reach 2.91 mm. Thirdly, under jointly the severe temperature gradient loads and maglev train loads moving at 100 km/h, maglev train can run smoothly through the U-girder, deflection and acceleration amplitude of the U-girder are far less than the limits. However, the maximum transverse tensile stress near the junction reaches 3.0 MPa and exceeds slightly the tensile strength, it implies that the U-girder has the cracking risk of concrete. [ABSTRACT FROM AUTHOR]

Severe cutaneous injuries may not heal spontaneously and may necessitate the use of supplementary therapeutic methods. Electrospun nanofibers possess high porosity and specific surface area, which provide the necessary microenvironment for wound healing. Here in, the nanofibers of Soluplus-soy protein isolate (Sol-SPI) containing mupirocin (Mp) were fabricated via electrospinning for wound treatment. The fabricated nanofibers exhibited water absorption capacities of about 300.83 ± 29.72% and water vapor permeability values of about 821.8 ± 49.12 g/m2 day. The Sol/SPI/Mp nanofibers showed an in vitro degradability of 33.73 ± 3.55% after 5 days. The ultimate tensile strength, elastic modulus, and elongation of the Sol/SPI/Mp nanofibers were measured as 3.61 ± 0.29 MPa, 39.15 ± 5.08 MPa, and 59.11 ± 1.94%, respectively. Additionally, 85.90 ± 6.02% of Mp loaded in the nanofibers was released in 5 days in vitro, and by applying the Mp-loaded nanofibers, 93.06 ± 5.40% and 90.40 ± 5.66% of S. aureus and E. coli bacteria were killed, respectively. Human keratinocyte cells (HaCat) demonstrated notable biocompatibility with the prepared nanofibers. Furthermore, compare to other groups, Sol-SPI-Mp nanofibers caused the fastest re-epithelialization and wound healing in a rat model. The findings of this study present a novel nanofiber-based wound dressing that accelerates the healing of severe skin wounds with the risk of infection. [ABSTRACT FROM AUTHOR]

Highlights The bio‐sandwich composites are lightweight, economical, recyclable, and easily obtainable. Sandwich panels comprising glass fiber/epoxy face sheets and hemp fiber/epoxy core with varying fiber orientations, thickness, and montmorillonite nanoclay are prepared by stirring the epoxy/clay mixture to have uniform dispersion followed by compression molding. The sandwich and monolithic composites are loaded under quasi‐static punch shear. The sandwich panel with 3 wt.% nanoclay shows optimum quasi‐static tensile modulus and strength than the neat panel. Energy absorption, and specific energy absorption of sandwich panels G0/H(0)5/G0‐0%, G0/H(0)10/G0‐0%, G0/H(0)15/G0‐0% are 2%, 76%, 111%, and 28%, 132%, 183% higher than same weight glass/epoxy composites G(0)5‐0%, G(0)8‐0%, G(0)10‐0%. Energy absorption and specific energy absorption of panels G0/H(0)3/G0‐3%, G0/H(0)7/G0‐3%, G0/H(0)9/G0‐3% are similar, 25%, 24%, and 18%, 55%, 57% higher than same thickness composites G(0)5‐0%, G(0)8‐0%, G(0)10‐0%. The energy absorption of sandwich panel G0/90/H(0)15/G90/0‐0% is 49% lower than same weight composite G0/90/(0)9/90/0‐0%. Similar behavior is observed for panels with ±45° face sheets, 0° core, and 0°/90° face sheets, ±45° core compared to composites. Therefore, sandwich panels with 0° face sheets and core outperform composites and can replace them in structural applications in automotive. Particularly, panels show greater improvement over same‐weight composites than same‐thickness ones. Energy absorption of sandwich panels having 0° and ±45° cores is comparable while it is higher than a panel with 0°/90° core, each of 0°/90° face sheets. This is observed for monolithic composites as well. The quasi‐static indentation response of bio‐sandwich composites is examined. Bio‐sandwich composites outperform synthetic composites, each of the same weight. Bio‐sandwich panels with 3 wt. % nanoclay perform better than the same thickness synthetic composites. The behavior of sandwich and monolithic composites varies with fiber orientations. [ABSTRACT FROM AUTHOR]

Composites of Polychloroprene rubber (CR, Neoprene rubber) reinforced with starch from non-edible variety of dioscorea tuber were prepared using three different vulcanizing systems. The cure, mechanical, solvent resistance and biodegradable characteristics of the composites were studied. The addition of starch from dioscorea tuber was found to improve CR's tensile strength. The maximum torque value increases with the loading of filler and it was found to be the highest at 20 phr. The addition of starch from dioscorea tuber was found to improve CR's tensile strength and highest value observed at 20 phr. Among the different curing systems studied, the modified DCP system shows maximum mechanical properties, optimum properties of the composites are at 20 phr. The values of the swelling coefficients were determined by examining the intake of the solvents N, N-dimethylformamide, acetonitrile, dimethyl sulfoxide and water by the composites. The soil burial test indicated that biodegradability of CR enhanced with the addition of starch. The findings of mechanical properties are supported by studies using scanning electron microscopy. Since starch is a naturally occurring biopolymer, adding it encourages microbial activity, which breaks down the composite components. This quality is essential for resolving plastic waste-related environmental issues. It is anticipated that the findings of this study will aid in the development of materials for specific product applications like gasoline hoses, tire sidewalls, seals, and so on. [ABSTRACT FROM AUTHOR]

As one of the hotspots in rock mechanics research, coal rock's dynamic tensile properties are crucial to the parameter selection of blasting engineering, mechanism studies of rock burst disasters, and stability control. The stress states of coal rock during indirect tension with Brazilian splitting and direct tension with split Hopkinson tensile bar (SHTB) were compared using numerical simulations, revealing the superiority of the direct-tension test. On this basis, systematic dynamic direct-tension tests of coal rock under the strain rates (124 to 247 s−1) were carried out utilizing the improved SHTB, and quasi-static tensile tests were performed for comparison. The results reveal that the connection mode of using high-strength adhesive paste specimens and gradient reinforcement with steel wire mesh is reliable for SHTB tests. However, the stress equilibrium is no longer satisfied if the strain rate exceeds 300 s−1, and the layered fracture of the specimen will occur. With an increase in strain rate, the dynamic elastic modulus increases linearly, the dynamic tensile strength tends to increase as an exponential function, and the dynamic increase factor (DIF) tends to increase linearly in two stages. The DIF grows slowly once the strain rate is over 180 s−1 and the dynamic ultimate tensile strength of the coal rock lies around 8 MPa. Finally, based on the improved Zhu–Wang–Tang (ZWT) model and the introduction of dynamic damage factor, the unified damage constitutive equation that can describe the strain rate effect under dynamic tension of coal rock is constructed. Moreover, the rationality of the constitutive parameter value is verified. Highlights: Superiority of direct tension test over Brazilian disk tensile test is revealed Functional relationship between tensile DIF and strain rate of coal rock isobtained Unified damage constitutive model of coal rock under dynamic tension isconstructed [ABSTRACT FROM AUTHOR]

Microwave-assisted mechanical rock-breaking can effectively solve the problems of low efficiency of hard rock-breaking and severe wear and tear of equipment. This study used granite as the research object and analysed electromagnetic–thermal characteristics and dynamic tensile characteristics of microwave-irradiated granite. The microwave irradiation problem was decomposed into the electromagnetic–thermal unidirectional coupling and thermal–mechanical unidirectional coupling problems for numerical solutions, and the weakening mechanism of microwave irradiation was discussed at the microscopic level. The results showed that the thermal stress generated by the rapid heating and selective heating characteristics of microwave irradiation is the dominant factor in microwave fracturing. The presence of thermal cracks affects the crack extension path, making the failure more complicated. Tensile failure is the primary mechanical mechanism that causes the macroscopic fracture of the specimen, and intergranular failure dominates the overall failure of the specimen. Microwave irradiation reduces the shear resistance of the specimen. Microscopically, the proportion of shear cracks gradually increases with the increasing of irradiation duration (TM). Macroscopically, the area of the wedge-shaped failure zone gradually increases. Highlights: The dynamic tensile experiment is used to evaluate the microwave weakening effect. Microwave irradiation effectively reduces the tensile strength and improves rock fragmentation. Proposed an FEM–DEM method for solving coupled electromagnetic–thermal–mechanical problems. The crack initiation, propagation, and coalescence process in the microwave-irradiated granite under dynamic Brazilian splitting experiments are reproduced. [ABSTRACT FROM AUTHOR]

Conductive polymer composites (CPC) are gaining increasing popularity due to their unique characteristics, which include light weight and the ability to conduct electricity. In this work, CPC were prepared by blending the polylactic acid (PLA) with a conductive filler, graphene nanoplatelets (GNP), at dosages ranging from 1 to 12 wt % using an internal mixer. The hot press machine was used to compress the CPC into thin sheet, and subsequently characterized for tensile, thermal, and electrical properties. The results showed that the addition of GNP at 7 wt % (percolation threshold) successfully transformed the PLA into an electrically conductive material. The tensile modulus increased with added GNP, but elongation at break and tensile strength exhibited an opposite trend. The incorporation of GNP also enhanced the composite's thermal stability. [ABSTRACT FROM AUTHOR]

The present study deals with the prediction of the strength of the glue joint stressed in tension on a local wood species called Terminalia Superba (Fraké) assembled according to the bevel configuration using two artificial intelligence models namely ANFIS and LSTM. The experimental data obtained during tensile tests on a tropical species allowed us to determine the mechanical properties taken as structural parameters for the LSTM and ANFIS models. The results of the analysis show that among all the LSTM methods, LSTM 'ADAM' offers a low root mean square error (RMSE), a high accuracy (Acc) (RMSE = 2.16, Acc = 0.756). For all methods, ANFIS obtained the best results, a high R-squared and a very low root mean square error (RMSE) (R-squared = 0.979, RMSE = 0.51). This indicates that the prediction of the tensile strength of the adhesive joint is more satisfactory with ANFIS than with LSTM. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) techniques, particularly Fused Filament Fabrication (FFF), have revolutionized prototyping and low-volume production. Improving the tensile properties of FFF-printed parts is a primary objective to elevate their functional utility. This study aimed to investigate the effects of annealing time (ATM), annealing temperature (ATP), and nozzle diameter (ND) on the tensile strength (TS) of two commonly used printing materials: Polyethylene Terephthalate Glycol (PETG) and PETG reinforced with carbon fibre (PETG-CF). Samples with varying ND (0.4 mm, 0.6 mm, and 0.8 mm) underwent annealing at ATP of 80°C and 100°C for ATM of 60 min and 120 min, respectively. Subsequent tensile tests were meticulously conducted, and regression models were employed to comprehensively analyse the influence of these control factors on TS. The findings from the tensile tests on annealed specimens revealed substantial improvements in TS for both PETG and PETG-CF materials. Statistical analysis, Taguchi method (TM), and response surface methodology (RSM) indicated that ND exerted a more pronounced impact on TS compared to ATM and ATP. By identifying the optimal control factor combinations for each material, the study pinpointed that the best TS was achieved at 0.8 mm ND, 120 minutes ATM, and 100°C ATP for PETG-CF. The remarkable enhancement in tensile properties for annealed FFF-printed parts underscores the potential of PETG-CF to replace structural metallic components in critical applications within the automotive and aeronautical industries. [ABSTRACT FROM AUTHOR]

Increasing global consumption of low-density polyethylene leads to more polymeric waste and challenges solid waste management. Therefore, the process of recycling or mixing recycled low-density polyethylene (RLDPE) with the same virgin low-density polyethylene (VLDPE) and enhancing the properties of this blend by adding different amounts of bioplastic such as Octanoate starch (OCST) is a good contribution to getting rid of plastic waste and obtaining new materials. This paper mixed the 20, 30 and 50 wt.% from RLDPE with VLDPE to determine the homogeneous blend. Also, 30, 40, and 50 wt. % from OCST were blended with homogeneous as a 20:80 RLDPE: VLDPE to obtain a new hybrid blend containing bioplastic. The scanning electron microscope (SEM) results showed the high surface roughness of the film RLDPE: VLDPE after adding the OCST. The tensile strength, elastic modulus, and hardness of the 20:80 RLDPE: VLDPE blend were 13.0 ± 1.467 MPa, 0.08 ± 0.016 MPa, and 42.3 ± 2.32 Shore A, while the tensile strength, elastic modulus, and hardness of the 12:48:40 RLDPE: VLDPE: OCST were 14.3 ± 1.626 MPa, 0.1 ± 0.032 MPa, and 50.1 ± 2.78 Shore A respectively. On the other hand, the Fourier-Transform Infrared (FTIR) indicated that the strong bands at 1746 cm−1, 2856 cm−1, and 2927 cm−1 indicated stretching deformation of the ester carbonyl group and the methyl and methylene groups of OCST with blend polymers, respectively. The thermal properties as melting point, heat energy consumption, and heat flow difference increased from 122.52 to 123.73°C, −389.41 to −144.43 (mJ), and −77.88 to −28.89 (J/g) when the OCST content increased from 20:80 RLDPE: VLDPE to 12:48:40 RLDPE: VLDPE: OCST. Thermal decomposition led to the formation of functional groups such as hydroxyl and carbonyl on LDPE baskets and an increase in the carbonyl index after adding OCST to the RLDPE: VLDPE blend. The best hybrid blend was 12:48:40 RLDPE: VLDPE: OCST. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the fracture behavior of human molars with extensive MOD restorations using short‐fiber‐reinforced resin composite of varying viscosities. Materials and Methods: Human molars were randomly divided into seven groups (n = 12): intact teeth (control); restoration using conventional high‐viscosity resin composite without (Filtek Z350XT, 3M) or with fibers (everX Posterior, GC); conventional low‐viscosity resin composite without (Filtek Supreme Flowable, 3M) or with fibers (everX Flow Dentin Shade, GC); bulk‐fill low‐viscosity resin composite (Filtek Bulk Fill Flow, 3M) or with fibers (everX Flow Bulk Shade, GC). Restorations were performed on extensive MOD preparations, following the manufacturers' recommendations for each material. Specimens underwent fracture strength testing (N) and fracture pattern (%) categorized as repairable, possibly repairable, or non‐repairable. Results were analyzed using a generalized linear model (N) and Fisher's exact test (%), with α = 0.05. Results: Restorations performed with high‐viscosity materials showed fracture strength values similar to the control and higher than those of restorations using low‐viscosity resin composites (p < 0.0001), except for the bulk‐fill low‐viscosity resin composite with fibers (p > 0.05). Teeth restored using low‐viscosity resin composite with fibers showed a higher % of repairable and possibly repairable fractures than the control (p = 0.0091). Conclusions: The viscosity of materials mediated the fracture strength, with restorations using high‐viscosity resin composites promoting values similar to the intact tooth; however, the presence of fibers influenced the fracture pattern. Clinical Significance: Teeth with MOD cavities restored with high‐viscosity resin composites showed similar fracture strength to intact teeth. Fiber‐reinforced low‐viscosity resin composite for the base of restoration resulted in a more repairable/possibly repairable fracture pattern. [ABSTRACT FROM AUTHOR]

This investigation focuses on the study of the effect of process parameters like peak current ( I p) , base current ( I b) , pulse frequency (F) , shielding gas flow rate (Q) on mechanical properties like yield strength (YS), ultimate tensile strength (UTS) and flexural strength (FS) of the welded joints during pulsed TIG welding of SAILMA 450 and EN14 B steels. Taguchi's L 2 5 orthogonal array has been used for conducting the tests. Multi-objective optimization has been performed using Grey relational analysis (GRA) in order to maximize the mechanical strength and to find out the optimal set of parameters. The optimum parametric combination is obtained at a peak current of 220 Amps, base current of 120 Amps, pulse frequency of 5 Hz and shielding gas flow rate of 17 l/min. Analysis of variance (ANOVA) is used to predict the significant process parameters. It has been observed from the ANOVA analysis that peak current and pulse frequency have more influence on the output responses than the shielding gas flow rate and base current. The results of the confirmatory test show an improvement of 0.5801 in the GRG, which is satisfactory. A microstructure study has been performed using scanning electron microscopy (SEM) for the optimal set of process parameters. [ABSTRACT FROM AUTHOR]