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Xuan paper is one of the most famous handmade papers in China and is an important paper for conservation. However, the evenness of Xuan paper has not yet received much attention. In this study, the distribution of the in-plane grammage and mechanical properties of Xuan paper are measured. It is found that the distribution of the in-plane grammage and mechanical properties of Xuan paper is uneven. In the handmade direction, the grammage and mechanical properties of Xuan paper are overall largest in the lower area, followed by the upper and middle areas. The sheet forming process of Xuan paper has an important effect on the distribution of in-plane grammage, mechanical properties, and fiber orientation of Xuan paper. The folded state has a negative effect on the mechanical properties of the folded area of Xuan paper. This study will help raise awareness of the unevenness in physical properties of Xuan paper, which is important in both conservation and research applications. [ABSTRACT FROM AUTHOR]

The mechanical properties of woven natural fiber reinforced polymers additively manufactured through Laminated Object Manufacturing (LOM) technology are investigated in this paper. The benefits of both the material and manufacturing process were combined into a sustainable practice, as a potential alternative to traditional synthetic composite materials made from nonrenewable crude oil with limited end-of-life alternatives. Woven jute fiber reinforcements are used to strengthen both synthetic and bio- thermoplastic polymers in creating highly biodegradable composite structures. Such materials, as one of the prospective alternatives for synthetic composites, can be used in many engineering fields such as automobile panels, construction materials, and commodity and recreational products including sports and musical instruments. A LOM 3D printer prototype was designed and built by the authors. All woven jute/polymer biocomposite test specimens made using the built prototype in this study had their mechanical (both tensile and flexural) properties assessed using ASTM test standards and then compared to similar values measured from pure polymer specimens. Improved mechanical characteristics were identified and analyzed. Finally, SEM imaging was performed to identify the polymer infusion and fiber-matrix bonding conditions. [ABSTRACT FROM AUTHOR]

Many researchers are interested in using natural fibres to treat due to recent advancements in polymer characteristics. The mechanical properties of three types of bars are studied in this paper: Cotton Fibre-Reinforced Polymer bars, Cotton/Carbon Fibre-Reinforced Polymer bars, and Cotton/Glass Fibre-Reinforced Polymer bars. The goal of the paper was to create low-cost bars with comparable mechanical performance and corrosion resistance to steel reinforcement. The bars were made using two methods: fibres immersed in polymer and fibres coated with polymer by repeated tension and relaxation of fibres. The second method produced better results in terms of the tensile strength of Cot.CFRP, Cot.GFRP, and Cot.FRP bars, which were 688, 477, and 284 MPa, respectively, and the stress–strain curve revealed brittle behaviour for all bars and modulus of elasticity of 43, 31 and 22 GPa. When sand was put on the bar's surface, the bars demonstrated a good connection with the concrete. It also showed good resistance to moisture, alkaline solutions and acids, as well as heat resistance at temperatures below 200°C. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) have high strength and stable chemical properties, offering the potential to enhance the mechanical performance of cementitious grouting materials and finding wide applications in the field. This paper reviews the recent research on the application of CNTs in cementitious grouting materials. It introduces the basic structure of CNTs and commonly used dispersion methods in cementitious grouting materials, analyzing and summarizing hydration and microstructure, mechanical properties, and early shrinkage performance of carbon nanotubes-cementitious grouting materials, highlighting current research challenges. Additionally, the future research on CNTs in cementitious grouting materials is also envisioned. [ABSTRACT FROM AUTHOR]

Underwater welding offers a wide range of applications in a variety of disciplines. The notion of underwater welding appeals to many in the naval construction industry since it effectively repairs colliding and damaged ships. This paper mainly focuses on the characteristics of underwater weldings, such as arc bubble behaviour, rapid cooling and underwater welded joints. The properties of bubble behaviour, its effect on process stability and process parameters that influence bubble generation are discussed. Rapid cooling is a crucial problem faced by Underwater Wet Welding (UWW). Reducing welding speed and employing induction heating techniques can control the cooling rate while welding. The influence of water flow on weld metal shows that cold cracking is directly connected to the worse mechanical characteristics of wet weld joints under various flow conditions. The mechanisms of porosity generation are investigated using slag formation, CO production, hydrogen diffusion, and short-circuiting. Weld metal porosity is reduced when the hydrogen level and CO formation are reduced. Finally, the recent developments and challenges faced in UWW and industrial applications are addressed. [ABSTRACT FROM AUTHOR]

The poor mechanical and tribological properties limit the higher requirements of aluminum alloys in engineering and industrial applications, which leads to the rapid development of aluminum matrix composites (AMCs). Particulate reinforced AMCs have attracted extensive attention in automobile, electronics and military industries due to their low density, high strength, and excellent wear resistance. However, the interfacial reaction between reinforcements and the Al matrix tends to occur in conventional preparation processes owing to the higher reaction temperatures. The spark plasma sintering (SPS) technique is considered to be an efficient method for the fabrication of metal matrix composites, which can achieve rapid sintering, lower sintering temperatures, and higher densities than conventional fabrication processes. In addition, SPS can produce AMCs with excellent non-porous microstructure, fine grain size, and a strong bonding interface between reinforcement and Al matrix. Therefore, the interfacial reaction is effectively controlled and the structural integrity is maintained, resulting in enhanced strength and ductility. Based on the advantages of particulate reinforced AMCs and the SPS technique, the particulate reinforced AMCs fabricated by SPS have been extensively studied in recent decades, but have not been systematically evaluated. Therefore, this paper reviews the state-of-the-art particulate reinforced AMCs fabricated by SPS, focusing on the microstructure characterization, strengthening mechanisms, and mechanical and physical properties. Furthermore, the future research priorities and challenges of the high-performance particulate reinforced AMCs fabricated by SPS are also prospected. [ABSTRACT FROM AUTHOR]

Quasi-static tensile tests are commonly used to determine the mechanical properties of fiber bundles. These tests are generally carried out at a low standard speed of 1 mm.min−1, which is recommended for elementary fibers, although other moderate and high speeds are rarely used. In this study, tensile tests were carried out on coir and sisal fiber bundles from the coastal region of Cameroon using four different speeds: 1, 2, 5, and 10 mm.min−1 to assess mechanical properties. Samples were prepared by attaching the two ends of each randomly selected fiber bundle to a paper frame to obtain a length of 30 mm. The results showed a significant effect of extension speed, indicating a decrease in tensile strength and Young's modulus, and an increase in strain at break with increasing speed. These trends were correlated with the power functions. A strong dependence between fiber bundle diameter and tensile strength was also observed. Furthermore, statistical analysis based on the Weibull distribution highlighted the dispersion of mechanical properties, demonstrating a reduction in dispersion with increasing extension speed for coir fibers. These data can be used to develop specific standards for these natural fibers and contribute to the advancement of composites based on plant fibers. [ABSTRACT FROM AUTHOR]

In this paper, the effect of a novel fibre reinforcement architecture in the adhesively bonded joint efficiency of natural fibre reinforced composites (NFRC) was investigated. Two different reinforcement techniques were used: intralaminar reinforcement (2D) and orthogonal-through-the-thickness reinforcement (3D). The aim of the novel architecture is to enhance the transverse properties of the adherend (transverse strength and fracture toughness) in order to delay or avoid delamination failures. A jute bidirectional fabric was used as a base primary reinforcement phase and curauá, sisal, ramie, hemp and glass fibres were used as secondary reinforcement phases for the 2D and 3D fibre reinforcement architectures. Single lap joints (SLJs) bonded with an epoxy adhesive used in the automotive industry were fabricated with these adherends and the efficiency of the joints was investigated by comparing them to glass (GFRP) and carbon (CFRP) pure synthetic fibre reinforced composite joints. It was found that the novel architecture was successful in reaching the failure load of the synthetic composite joints for SISAL 3D, CURAUÁ 2D and CURAUÁ 3D SLJs. Therefore, NFRC bonded joints can be a viable replacement for synthetic fibre composite joints at no load-bearing loss. [ABSTRACT FROM AUTHOR]

This paper gives an investigation into the morphological analysis of boron carbide and the mechanical properties of the Jutton-Glass hybrid polymer nanocomposites. As reinforcements, hybrid nanoparticles comprising boron carbide and graphene nanoplatelets were used. For laying the composites, the vacuum bagging technique was used with the composition of hybrid nanomaterial taken as 0, 0.25 and 0.5 wt.% of Gr and B4C, and the samples were tested for mechanical properties as per ASTM standards. The samples prepared have been subjected to various tests, and the results are reported. Before the preparation of composites, the polymer was mixed with surface-modified nanomaterial and stability tests were conducted to assess uniform dispersion with the aid of UV spectroscopy, and the outcomes showed that the samples had been exceptionally uniform over some time. It is determined that the mechanical behavior of hybrid composites, which include B4C with Gr, shows better properties than base, B4C, and Gr. However, the multi-layered samples with graphene nanoplatelets also showcased encouraging mechanical properties like hardness and tensile strength. [ABSTRACT FROM AUTHOR]

In this paper, different Mn content doped potassium sodium niobate (KNMN) coatings were prepared by plasma spraying technology, and the effects of different Mn content doping on the microstructure and electrical properties of the coatings were investigated. The results showed that the mechanical and electrical properties of the coatings showed a trend of increasing and then decreasing with the increase of Mn doping content, and the best mechanical and electrical properties of the coatings were obtained when the Mn doping content was 2 mol%. [ABSTRACT FROM AUTHOR]

As a waste of wood processing, a large accumulation of sawdust will have an impact on the environment. In this paper, sawdust is added to concrete to explore the influence of sawdust on the performance of concrete. Experiments show that sawdust water absorption and friction are the key factors affecting the rheological properties. Through Inductively coupled plasma mass spectrometry, it can be understood that sawdust fiber can adsorb ions, so it will have an impact on early hydration. Nanoindentation shows that sawdust changes the properties of hydration products, which is related to the adsorption of ions by sawdust. Sawdust hurts the compressive strength and heat resistance of concrete. Mercury intrusion porosimetry and Ultrasonic pulse velocity results show that similar to wood chips will lead to a decline in the interfacial transition zone, resulting in increased porosity, but the adsorption of chloride ions on wood chips is beneficial to the protection of concrete, so in the appropriate dosage conditions, wood chips will not significantly affect the performance of concrete. [ABSTRACT FROM AUTHOR]

Needled composites have stronger interlaminar properties compared to two-dimensional fiber composite structures due to the introduction of z-directional fibers in the fiber composite layup. An effective multi-scale finite element model is developed in this paper for the complex structure of needle-punched composites. Three scales, namely fRVE, pRVE, and lRVE, are modeled from the fiber scale, the delamination scale, and the laminate scale. using ABAQUS, periodic boundary conditions are applied to the RVEs at different scales to obtain the effective mechanical properties of various RVEs. Meanwhile, the effect of needling density on the needled composites is predicted by applying the above multi-scale model. The increase of needling density can enhance the out-of-plane effective mechanical properties of the composites, but it also weakens the in-plane effective mechanical properties. The maximum error of the elastic modulus calculation is 17.68% with that of the reference, thus verifying the rationality of the multi-scale model. [ABSTRACT FROM AUTHOR]

AbstractThis paper proposes an efficient technique for the fabrication of macro fiber composite (MFC) and characterizes the properties of MFC under dynamic voltage. First, the fabrication process is described in detail. Then, the effects of peak-to-peak value, frequency and dc bias on the electric-field-induced strain are analyzed. Finally, the mechanical properties are evaluated based on the mixing rules, and the prediction model of electrical parameters is established using the fitting functions. The experimental results show that the proposed fabrication technique effectively suppresses the generation of defects and the electric field variation has significant effects on the actuating properties. [ABSTRACT FROM AUTHOR]

AbstractAuxetics have emerged recently as an exciting class of mechanical metamaterials that are identified by negative Poisson’s ratio. The mechanical properties of rationally designed auxetic metamaterials are mostly influenced by their topological characteristics rather than the material properties of their constituent material. The goal of this paper is to use optimization algorithms to achieve the desired target mechanical properties for reentrant auxetic metamaterials. The GEKKO optimization package in Python is used for optimizing the geometry of auxetic lattice structures. Several mechanical properties including Poisson’s ratio, relative Young’s modulus, relative yield stress, and relative energy absorption capability, as well as the noted properties normalized with respect to relative density and relative Young’s modulus are chosen for being minimized or maximized. ANSYS finite element package is also implemented for validation of the results obtained from the optimization algorithm. According to the results, to achieve the maximum magnitude of Poisson’s ratio (positive and negative), the size of the unit cell in the lateral direction must be selected to be maximum and the thickness must become minimum. Moreover, to achieve the maximum value of the relative Young’s modulus or energy absorption in any direction, the size of the unit cell in that direction must be maximized. Also, to achieve the maximum amount of relative yield stress in both directions, the unit cell must have a maximum thickness and an internal angle close to zero. [ABSTRACT FROM AUTHOR]

Functional nanocomposites have garnered considerable attention due to their ability to exhibit multifunctional properties and achieve exceptional performance. This current paper aims to analyze the individual and combined effects of magnetite (Fe3O4) and Graphene nanoplatelets (GNPs) on the mechanical, thermal, and morphological properties of a blend consisting Thermoplastic elastomer (TPE) which is made up of Natural rubber (NR) and Polyaniline (PANi). Both nanocomposites were fabricated via melt blending method using an internal mixer, followed by compression via hot/cold pressing. The incorporation of Fe3O4 was observed to consistently enhance the flexural and impact properties compared to GNP-based nanocomposites. Notably, the nanocomposites filled with 6 wt% Fe3O4 displayed the highest flexural strength (2.1 MPa), flexural modulus (31.1 MPa), and impact strength (4.4 kJ/m2). Results from thermogravimetric analysis and differential scanning calorimetry demonstrated a significant improvement in thermal stability within the nanocomposites. The introduction of nanoparticles led to a delay in decomposition and melting processes. The hybridization of Fe3O4 and GNP proved effective in synergistically enhancing both mechanical performance and thermal stability. At optimum content, scanning electron microscopy micrographs revealed a uniform dispersion of Fe3O4/GNPs within the TPE-PANi blend, accompanied by strong interactions between the components. [ABSTRACT FROM AUTHOR]

AbstractFibre reinforced metal laminates (FMLs) are widely used in various fields due to their excellent properties. However, the weak interlayer properties of FMLs limit their applications. In this paper, the interlayer properties of FMLs are enhanced by anodising the 2024-T3 aluminium alloy layer in FMLs or by epoxy matrix modification of graphene nanoplatelets (GNPs). The effect of both synergistic impacts on the interlayer properties of most FMLs is investigated. The FMLs were manufactured using the wet lay-up technique using 2024-T3 aluminium alloy, E51 epoxy and EW100 glass fibre. The results showed that the type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of FMLs after anodic oxidation treatment were increased by 406.4%, 10.3%, 18.3%, 42.6% and 28.3%, respectively, compared with those of pure FMLs. The type I fracture toughness, tensile strength, flexural strength, interlayer shear strength and single layer shear strength of the GNPs-modified FMLs matrix were increased by 280.4%, 3.7%, 6.8%, 34.5% and 19.1%, respectively, compared with those of pure FMLs. Moreover, the synergistic effect of FMLs indicates that the simultaneous anodic oxidation and GNPs modification of FMLs can lead to the best mechanical properties of FMLs. Microscopic images and schematics illustrate the toughening mechanism of anodising and GNPs, including the enhancement of aluminium/resin interface and fibre/resin interface and the enhancement of resin matrix properties. [ABSTRACT FROM AUTHOR]

The usage of high strength steel (HSS) is steadily increasing, primarily driven by the pursuit of weight reduction, leading to a subsequent decrease in greenhouse gas emissions. This paper investigates the impact of various post-weld heat treatment (PWHT) temperatures of 525 °C, 550 °C and 575 °C with a holding time of 2 h on both the microstructure and mechanical properties of weld metal produced using a HSS metal cored wire. The investigation reveals that PWHT does not significantly alter strength but has a more pronounced influence on toughness. The as-welded condition exhibited the highest toughness. Among the samples subjected to the PWHT, the one treated at 575 °C showed the highest impact energy, reaching 69 J at −60 °C. This outcome is attributed to the increased presence of acicular ferrite in the microstructure, surpassing that of samples subjected to PWHT at different temperatures. [ABSTRACT FROM AUTHOR]

AbstractBionic porous structure has been widely used in the field of bone implantation, because it can imitate the topological structure of bone, reduce the elastic modulus of metal bone implantation, and meet the mechanical properties and material transmission characteristics after implantation. This paper mainly studies the effects of different bionic porous structures on the mechanical and material transport properties of bone scaffolds. Firstly, under the same porosity condition, 12 groups of bionic porous structures with different shapes were designed, including G, P, D, I-type three period minimal surface (TPMS) and Voronoi porous structures with different irregularities. Then uses ABAQUS to carry out mechanical finite element simulation on different bionic porous structures, and uses Ti-6Al-4V alloy as forming material, uses laser powder bed fusion technology (LPBF) to prepare the scaffold, then carries out compression experiments. At the same time, COMSOL software is used to simulate the flow characteristics, analyze the permeability characteristics, and verified through cell experiment in vivo. The results show that the mechanical and permeability are different with vary scaffolds. In terms of topology, the morphological characteristics of TPMS are similar to trabecular bone, its compressive strength is relatively strong. Voronoi scaffold has lower elastic modulus, which can provide sufficient mechanical support while reducing stress shielding. In addition, the permeability of TPMS scaffold is better than Voronoi scaffold, which is helpful to promote cell proliferation and bone ingrowth. These bionic porous structures have their own advantages. Therefore, when designing porous structures for bone implantation, it is necessary to select the appropriate porous structure according to different bone implantation requirements. The research will help promote the clinical application of porous structures in the field of bone implantation, and provide theoretical support for the exploration of bone implantation structure design. [ABSTRACT FROM AUTHOR]

AbstractIn the Marine environment, the invasion of various harmful ions (e.g., Na+, and Cl−) into the concrete can lose and deteriorate the interfacial transition zone (ITZ) which is the weakest area in concrete. The degradation of ITZ results in a decline in the mechanical performance and durability of concrete, making it crucial to study how to improve the stability of the interface transition zone. In this paper, a systematic review of the modification mechanisms of five different types of zero-dimensional nanoparticles in the ITZ was investigated, focusing on mechanical properties and durability. The evolution and deterioration of the ITZ in concrete in the Marine environment were studied, and also the modification mechanism of nanomaterials on this deterioration. The results indicate that the addition of nanoparticles to enhance the microstructure of ITZ can effectively improve the performance of the interface transition zone. This is primarily achieved through mechanisms such as filling effect, nucleation effect, and hydration promotion. These findings lay the foundation for future exploration of cement-based materials in marine environments. [ABSTRACT FROM AUTHOR]

In this paper, the contact heating technology was combined with the warm and hot stamping process of high-strength aluminum alloy, and the corresponding experimental device was developed. For the contact heating-warm stamping process, it's found that as the heating temperature increases, the mechanical properties of the parts first decrease and then increase, while the springback decreases. Meanwhile, for the contact heating-hot stamping process, it's found that the aluminum alloy sheets experience large plastic deformation during contact heating, resulting in the refinement of microstructure and the increase in dislocation density, and the performance of the formed parts is improved. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is a key technology for the individualized and resource-efficient production of structural components. Recent developments in manufacturing technologies enable improved quality of additively manufactured components and therefore they become more and more important in lightweight constructions. An example is the substitution of solid material by porous lattice structures. Those embedded lattice structures lead to highly weight-efficient structures. Most recent investigations focus on numerical and experimental studies to describe the mechanical behavior of lattice structures. In this paper, a method to determine analytical expressions for the axial stiffness properties of lattice structures is presented. The displacement method and direct stiffness method are used to derive symbolic parameter-dependent formulas for the axial stiffnesses and effective Young's moduli for f2cc,z, and bcc unit cells. Furthermore, an empirical approach based on Finite Element simulations is presented to describe the stiffness reduction for non-embedded or rather free lattice structures. The results are further validated by physical experiments. Stereolithography is used for specimen production. f2cc,z, and bcc lattice structures are embedded in thin-walled rectangular aluminum tubes and tested under compression load. Furthermore, lattices without a surrounding tube are tested. The analytical and empirical solutions are in good agreement with the experimental and numerical results. [ABSTRACT FROM AUTHOR]

Probiotic products' economic value and market popularity have grown over time as more people discover their health advantages and adopt healthier lifestyles. There is a significant societal and cultural interest in these products known as foods or medicines. Products containing probiotics that claim to provide health advantages must maintain a "minimum therapeutic" level (107-106 CFU/g) of bacteria during their entire shelf lives. Since probiotic bacteria are susceptible to degradation and reduction by physical and chemical conditions (including acidity, natural antimicrobial agents, nutrient contents, redox potential, temperature, water activity, the existence of other bacteria, and sensitivity to metabolites), the most challenging problem for a food manufacturer is ensuring probiotic cells' survival and stability enhancement throughout the manufacturing stage. Currently, the use of plant-based hydrogels for improved and targeted probiotic delivery has gained substantial attention as a potential approach to overcoming the mentioned restrictions. To achieve the best possible results from hydrogels, whether used as a coating for encapsulated probiotics (with the goal of stomach protection) or as carriers for direct encapsulation of live microorganisms should be applied kind of procedures that ensure high bacterial survival during hydrogels application. This paper summarizes polysaccharides, proteins, and lipid-based hydrogels as carriers of encapsulated probiotics in delivery systems, reviews their structures, analyzes their advantages and disadvantages, studies their mechanical characteristics, and draws comparisons between them. The discussion then turns to how the criterion affects encapsulation, applications, and future possibilities. [ABSTRACT FROM AUTHOR]

The aim of this article is to investigate the effect of weave structures and thread densities on the cover factor and mechanical properties of cotton spandex woven fabrics. 98% cotton and 2% spandex poplin, twill, and sateen woven fabrics of different thread densities were used in this research for investigation. In this investigation, total samples of 15 types with miscellaneous textures such as plain (1/1), twill (1/4), and 7 ends sateen (1/6) were used. Yarns were assessed using microscope with its morphological views and outer shape views to confirm the existence of cotton fibers. In the microscopic observations, the outer shape of cotton yarn was seen with full of hairy fibers at the slope which guaranteed the existence of cotton content in these cellulosic fabrics. The stretching behaviors such as stretch, growth and recovery were measured in agreement with the test method provided by ASTM D3107 Standard along with apposite equations as mentioned underneath the paper. Using weave coefficient, the values of cover factors were measured with suitable equations. The fabrics of plain weave exposed the highest values of cover factors due to having higher interlacement points than any other weave structures conducted in this research. The fabrics of sateen weave exposed excellent mechanical properties with its stretch, growth and recovery values due to having fewer binding points in its repeat size, than any other weave structures carried out in this research. This research is practice based and it opens possible ways for the scholars to further study in this field. [ABSTRACT FROM AUTHOR]

Presuming that the filler structure can regulate the flame retardancy of polymeric materials, this study investigates the flame-retardant properties of EP-containing phosphorus/silicon. Sepiolite (Sep) fibers and SiO2 nanoparticles are shown to synergistically enhance the flame retardancy of EP-based composites. The underlying retardant mechanisms of the synergistic effect are also discussed and the mechanical properties of EP-based composites are examined. Among the prepared composites, EP/DiDOPO/Sep5&SiO25 (DiDOPO = derivative of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) achieved the maximum limiting oxygen index (29.4%) and a UL-94 V-0 rating. The EP/DiDOPO/Sep5&SiO25 composites also minimized the peak heat-release rate and total heat release and maximized the strength and modulus. [ABSTRACT FROM AUTHOR]

Most bulk metallic materials reveal an increased strength but a loss of ductility after cold deformation, a phenomenon known as the strength–ductility trade-off. In this study, we propose a strategy to overcome this problem by introducing a high density of crystalline defects into a Fe-based metastable alloy by refining grains to a nanometer scale. This procedure effectively enhances the kinetics and reduces the driving force for transformation-induced plasticity (TRIP). Consequently, the TRIP effect originally occurring at cryogenic temperature in the studied alloy becomes active at ambient conditions, contributing to a strength–ductility synergy and overcoming cold working induced sacrifice of ductility. High-density crystalline defects were introduced into a metastable alloy, leading to an increase in TRIP temperature. This helps to overcome the strength–ductility trade-off in the severely plastic-deformed alloys at ambient conditions. [ABSTRACT FROM AUTHOR]

Sepiolite is a fibrous clay mineral, which is mostly associated with a semi-arid to arid climate, with characteristics intermediate between kaolinite and montmorillonite minerals. An experimental study was conducted, with the goal of creating a substantial database of physical, microstructural, and geotechnical characteristics of sepiolite to develop its applications as a natural resource that is explored as the main deposit of Iran. It has been found that sepiolite soils were lightweight, porous, and cohesive with negligible settlement and swelling properties and almost high UCS values. Various analysis were performed to characterise the macroscopic behaviour (Atterberg limit, physical, and compressibility tests), microstructural, chemical, and mineralogical characterisations by chemical analysis, X-Ray diffraction, and Scanning Electron Microscopy. At first glance, sepiolite soils showed high liquid limits with medium to high plastic indices which can result in problems including creation of up and down movements in foundations. After mixing with silt and fine sand to decrease high liquid limit and optimum moisture amounts, sepiolite is suitable candidate for engineering applications (including clay liners, clay cores, etc.) due to its compressibility and strength characteristics. In conclusion, sepiolite soils are strongly recommended for geo-environmental structures due to their adsorption capacity, low permeability coefficient, and suitable strengths. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of poly (ethylene glycol) (PEG) on the properties of nanocomposites consisting of polylactic acid (PLA) and 3-aminopropyltriethoxysilane-modified bacterial cellulose (MBC) nanofibers. Differential scanning calorimetry (DSC) studies indicated that the presence of PEG enhanced the chain mobility of PLA during crystallization, thereby enabling the MBC to act as efficient nucleation agents. Furthermore, DSC and X-ray diffraction (XRD) analyses provided evidence for the formation of two distinct crystal structures, namely α and α,' as well as various spherulitic dimensions. Finally, the toughening of PLA was occurred by adding PEG to PLA and ternary nanocomposites. [ABSTRACT FROM AUTHOR]

Selective Laser Melting (SLM) preparation of TiN-reinforced 316L stainless steel effectively addresses the weaknesses of 316L stainless steel in terms of strength and hardness. While ensuring the flowability of the composite powder, this study employs dual-sized TiN particles to enhance 316L stainless steel. Experimental results indicate that micrometre-sized TiN particles are embedded in the matrix, and other TiN particles dissolve and re-form into cubic TiN particles with a diameter of around 200 nm. Samples produced at high laser energy density exhibit high density, consistently above 99%. The average grain size of the austenite is refined to 2.38 μm, and the tensile samples with a 90° interlayer rotation angle and island size of 60 × 10mm2 exhibit a maximum yield strength of 661 MPa, ultimate tensile strength of 950 MPa and elongation of 35.5%. Samples with lower laser energy density demonstrate the highest microhardness, reaching 365 HV. The corrosion resistance of samples with different scanning strategies is similar to pure 316L stainless steel, with the 67° interlayer rotation angle strategy showing the optimal corrosion resistance. [ABSTRACT FROM AUTHOR]

The present work describes the effect of welding parameters and tool pin features during friction stir welding of dissimilar AA6082 and AA7050. Mechanical behaviour of dissimilar joints fabricated by using two distinct tool pin features, welding speed (WS), and rotary speed (RS) were compared for superior weld properties. All joints fabricated from tool having threaded cylindrical (TC) pin feature were defect-free, whereas welds fabricated by the plain cylindrical (PC) pin tool at 800 rpm RS using different WS were found defective. At the same RS and WS parameters combinations, the width of the softened region was found comparatively less in PC tool welds. The highest ultimate tensile strength (UTS) and elongation of 187.33 MPa and 7.55% were obtained for weld fabricated from TC tool at 180 mm.min−1 WS and 800 rpm RS. However, the highest yield strength (YS) value of 168.8 MPa was obtained for dissimilar joints produced using the PC tool at 180 mm.min−1 WS and 1600 rpm RS. The tensile specimens of defect-free dissimilar joints were fractured from respective minimum hardness locations in ductile mode. [ABSTRACT FROM AUTHOR]

The widely used Vawter-Fung (VF) lung tissue constitutive model, originally developed to model respiration, was assessed for applicability to impact human body models (HBMs). A review of the mechanical properties of lung tissue demonstrated existing parameter sets for the VF model encompassed a wide range of stiffness relative to experimental data. Consistent experimental datasets of lung tissue for uniaxial and biaxial tension were identified, and new parameters were fit to the VF model. A thoracic pendulum impact using a contemporary HBM was used to assess existing literature parameter sets, and the new parameters. The VF model parameters presented in this study produced uniaxial and biaxial tension response with improved hyperelastic response compared to experimental data and previously reported parameters. The VF surface tension component did not contribute substantially to the lung response in impact. The proposed VF model parameters were numerically stable for impact simulations and use in HBMs. [ABSTRACT FROM AUTHOR]

In order to improve the thermal insulation and smoking properties of expanded vermiculite matrix composites, a kind of expanded vermiculite (EV)/chitosan (CS) composites was prepared by hot pressing. The effects of CS on smoke density, fire-resistance, insulation, and mechanical properties of the EV/CS composites were studied. The results show that with the increase of CS content, the smoke absorption performance and energy storage modulus of the composites is improved. Thermogravimetric (TG) analysis shows that the thermal stability of the EV/CS composite is improved by the presence of chitosan. The pores appear on the surface of the composites after the single-side fire-resistance test. After that, the thermal conductivity of the composites gradually decreases and the insulation performance is improved as the CS content increases. The CS carbonized during the preparation of the composites and thermal decomposition during the test. The morphology results show phase separation of the composites, and the porosity of the composites increases after the test. The reticular structure formed between the EV particles, sodium silicate, and CS molecules reduces the strength loss of the composites. [ABSTRACT FROM AUTHOR]

This study aims to assess the feasibility of including coal-bottom ash (CBA) as a substitute for cement and fine aggregate, with a replacement ratio of 20%, and 75%, respectively, in the production of lightweight foamed concrete (LWFC) at two different densities: 1300 kg/m3 and 1700 kg/m3. The study provided data on both its fresh and hardened states. These include water absorption, density, compressive, splitting tensile strength, rupture modules, modulus of elasticity, X-ray Diffraction, and Field Emission Scanning Electron Microscope. The findings indicated that including CBA as a substitute for cement and fine aggregate can yield environmentally friendly foamed concrete suitable for structural applications, exhibiting a compressive strength of up to 25.5 MPa. In addition, decreasing the CBA aggregate size in specimens with a density of 1300 kg/m3 resulted in increased strength. The mixes that included CBA contained additional C-S-H gels, which led to a more compact structure. [ABSTRACT FROM AUTHOR]

The issue of whether CoCrFeNi is a single-phase or dual-phase high-entropy alloy (HEA) has long been in dispute. In this study, CoCrFeNi has been verified to be a dual-phase HEA composed of dendritic phases with an FCC structure and inter-dendritic phases with a BCC structure. The BCC phases within inter-dendritic regions are identified as Cr3O oxides which form inevitably under the arc-melting process. Undercooling treatment under a strong magnetic field can regulate the composition and precipitation of the BCC phase, refine the grain size, and enhance the solid solubility, consequently, the mechanical performances of CoCrFeNi HEA are effectively enhanced. [ABSTRACT FROM AUTHOR]

The comparative assessments and an overview of mechanical, chemical, and physical properties of rail axles are presented. This review focused on the effects of compositions and microstructure on fatigue, fretting and corrosion fatigue of rail axles. The two main steel grades: low carbon steels for commuter trains and high strength low alloy steels for high-speed trains have ferrite-pearlite microstructures with 20–40 µm ferrite grain sizes. Minimum allowable yield and ultimate tensile strengths are 330 MPa and 600 MPa, and the minimum longitudinal and transverse toughnesses are 35 J and 22 J. Most axle failures are associated with surface and sub-surface defects with micro-cracks nucleating from ballast (small-sized pebbles in rail tracks), minute oscillatory movement leading to fretting, microstructural inclusions, and corrosion pits. The implications for structural integrity are highlighted and areas for future research directions are highlighted. [ABSTRACT FROM AUTHOR]

Silicone rubber (SR) is high-voltage insulator, but suffers from poor mechanical properties. Nanoparticle addition is a promising way to combat this problem. Herein, SiO2, Al2O3, MgO, SiC and thermally modified SiC nanoparticles were used to improve electrical resistivity, thermal stability and mechanical properties of SR. Surprisingly, electrical resistivity of SR was enhanced by one-order-of-magnitude by incorporation of small amount of nanoparticles, which induced nano-scale traps to capture charge carriers and restrict SR molecules conformation. Tensile strength and modulus of SR increased by SiO2, Al2O3, MgO and SiC incorporation, while decreased elongation at break, as a consequence of agglomeration as detected by microscopic observations. Nano fillers restricted the motion of polymer chains, so storage modules and hardness were increased. Addition of 2 phr SiC resulted in less polarization current comparably. Correspondingly, dielectric breakdown strength of the assigned sample was increased. SiC thermally modified interface is more conductive than the other parts of the matrix reduced charge accumulation and provide more conductive ways for increased charge carriers mobility, dissipate more charges and then increased dielectric breakdown strength. Dynamic-mechanical-thermal analyses demonstrated that storage modulus of SR nanocomposites was comparatively higher than neat SR, owing to rigidity contributed from SiO2 and SiC nanoparticles. Evidently, glass transition temperature shifted to a higher temperature (−109°C) compared to the neat SR (−127°C). Thermogravimetric analysis witnessed superiority of thermal stability of nanocomposites compared to SR, featured by 35°C rise in degradation temperature. The presence of nanoparticles in the polymer matrix acts as a barrier and prevents the release of gaseous products from burning and the entry of oxygen into the system lead to increase thermal stability. [ABSTRACT FROM AUTHOR]

The utilization of marine resources (e.g. seawater, coral sand or sea sand, and coral coarse aggregate) for the preparation of seawater coral aggregate concrete (CAC) in reef or island areas contributes to the decreased construction periods and costs for offshore projects. Nevertheless, the high porosity and brittleness of coral aggregates affect the mechanical characteristics and durability of CAC and its structures. In this study, slag-based geopolymers were utilized as substitutes for ordinary Portland cement for preparing geopolymer-based seawater coral aggregate concrete (GPCAC). The mechanical properties of GPCAC and CAC under seawater drying-wetting cycles were explored, and their degradation mechanisms in terms of mechanical characteristics were estimated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results pointed out that GPCAC exhibited better resistance to seawater attack than CAC after being subjected to seawater drying-wetting cycle environments. When subjected to 60 °C seawater corrosion in drying-wetting cycles for 12 months, the cubic compressive strength, elastic modulus, and axial compressive strength of CAC degraded by 14.4%, 13.0%, and 16.9%, respectively, while those of GPCAC only reduced by 5.4%, 11.8%, and 3.1%, respectively. It is concluded that the excellent pore structure, dense microstructure, and stabilized hydration products of geopolymers are responsible for their superior resistance to seawater attack compared to cement-based materials. [ABSTRACT FROM AUTHOR]

Metals and alloys with heterogeneous microstructures exhibit an enhanced combination of strength and ductility, compared to their counterparts with homogeneous microstructures. Additive manufacturing (AM) techniques offers a new opportunity to induce heterogeneous microstructures in a wide range of metals and alloys, thereby optimizing their mechanical properties. In this review article, we focus on four types of heterogeneous microstructures induced by AM: lamellar, gradient, laminated, and harmonic ones. We will introduce (i) the tailored generation of heterogeneous microstructures, (ii) the effects of characteristic solidification conditions, and (iii) the intricate phase transformation in laser-based AM process. Furthermore, we discuss the features, advantages, and potential applications of the metals and alloys with heterogeneous microstructures made by AM. To conclude, we discuss current challenges and future opportunities in this field. Additive manufacturing offers the opportunity of creating heterogeneous microstructures that enhance the strength-ductility synergy in metals and alloys. We review generation methods, solidification effects, heat treatment, and potential applications. [ABSTRACT FROM AUTHOR]

Kevlar fiber is a widely utilized fiber with applications in the aerospace, automotive, athletic, wind energy, medicinal, optical, and defensive fields. Kevlar fiber reinforced composites, unfortunately, are constrained in their development by weak interfacial adhesion with polymer matrix and fiber degradation in the presence of UV light. Both the polymeric epoxy matrix and the Kevlar fibers lose some of their mechanical qualities when exposed to UV radiation. Surface modification of the reinforcement fibers is one of the effective ways to improve the mechanical performance of fiber-reinforced composites. In order to enhance the Kevlar fibers resistance to UV deterioration, the fiber was hydrothermally (HT) treated with UV absorber Titanium Dioxide – nano particles (TiO2-np) after being acid functionalized with hydrochloric acid. The modified fibers and epoxy resin were combined during the compression molding process to fabricate the Kevlar Fiber Reinforced Composite (KFRC). The physical and chemical properties of modified KFRC before and after UV treatment were examined using UV-Visible and Fourier Transform Infrared spectroscopy. Scanning Electron Microscope micrographs have evidenced that the TiO2-np layer was successfully deposited onto the surface of the Kevlar fiber. It was also observed that after 180 hours of UV exposure, the average Young's modulus of unmodified KFRC dropped by 21.9%. [ABSTRACT FROM AUTHOR]

The main objective of this study was to examine the combined effect of ground recycled concrete cement (GRC) and thermo-activated recycled concrete cement (TARC) on properties of mortar. The physical, chemical and microstructural tests were conducted to characterize GRC and TARC before mortar mixtures were produced. The microscopic morphology of GRC and TARC revealed uneven edges and a rough surface that is slightly porous. The GRC and TARC powders were used to replace cement in the range of 0-50% at increments of 10% by volume. The fresh, mechanical, microstructure, and durability characteristics of mortar were tested for different proportion of GRC and TARC as partial replacement of cement. The usage of GRC and TARC decreases the workability of mortar marginally. However, the mechanical performance of the mortar mixtures showed an increasing trend when GRC and TARC share increases in the mixture. Predominantly, compressive strength, bulk density, and ultrasonic pulse velocity (UPV) have all been increased by as much as 20% cement replacement. Furthermore, the incorporation of GRC and TARC enhances the mortar's durability properties. The microstructure analysis reveals that 20% replacement (GT20) mix has superior structural compactness. In general, partially substitution of GRC and TARC by ordinary Portland cement improves several characteristics of mortar. This will help solve the most prevalent problems that concrete produces, including the high embedded carbon dioxide creation, the high resource usage, and the high waste generation after demolition. [ABSTRACT FROM AUTHOR]

The study of the mechanical properties of 3D printed food is crucial for food personalisation. Texture impacts the sensory experience along the oral food consumption. This work aimed to investigate the mechanical properties of post-processed printed food samples with different porosity topologies (triangled-shape/squared-shape). Image analysis showed changes in the structure before and after post-processing. The mechanical properties characterised via 3-point bending tests revealed that triangle-shaped topologies presented lower strength (20% less) and higher flexural stiffness (-20%) when compared to the square-shaped topologies. A qualitative comparison of the porosity topologies and their role in the stiffness of structures under tensile and bending loads was performed via finite element models. The flexural stiffness varied between the triangle-shaped designs (13-35%) but remained almost constant for squareshaped designs (40-43%). The results presented in this work showed that the mechanical properties of 3D-printed food could be modified by the selection of porosity topology. [ABSTRACT FROM AUTHOR]

This study employed laser directed energy deposition (DED) with in-situ ultrasonic vibration to obtain AA7075 deposits. The results showed that with ultrasonic treatment, the grain morphology of DED produced AA7075 was changed from columnar grains with an average area of 1751 µm2 to equiaxed grains of 118.2 µm2, representing a reduction of about 93%. Also, the application of ultrasonic treatment led to the increase of average hardness from 93.1 HV to 110.2 HV, and the increase of average ultimate tensile strength from 226.8 MPa to 314.7 MPa, representing relative increases of 18.36% and 38%, respectively. However, it did not result in a significant reduction of ductility. It is believed that ultrasonic vibration promotes the formation of additional nucleation sites due to cavitation and acoustic streaming, as well as the formation of secondary phase particles at grain boundaries. Both mechanisms effectively augment the mechanical properties of DED produced AA7075. [ABSTRACT FROM AUTHOR]