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In spite of significant efforts to investigate the ability of hydrogenated and fluorinated graphene to conduct heat, little research has focused particularly upon their other thermal properties, such as thermal contraction and heat capacity, which have implications for the development of thermal nanotechnology. In an attempt to determine these thermal properties, a few experiments have been carried out, with rather conflicting results. In the present study, calculations were performed using molecular dynamics to investigate the thermal properties of graphane and fluorographene and especially the phenomena involved. The thermal expansion coefficients and heat capacities of the two-dimensional materials were determined at different temperatures. The results indicated that graphane is thermally contracted more significantly than graphene. The calculated molar heat capacity at constant volume is about 25.00 J/(mol·K) for graphene and about 29.26 J/(mol·K) for graphane. The specific heat capacity of fluorographene is always lower than that of graphane. A negative relationship does exist between the binding energy and the temperature.

This paper proposes a numerical approach for predicting residual stresses induced during the additive manufacturing (AM) of polymer composites and their effect on the deformation behavior of the composites. A finite element (FE) model was developed on Abaqus/Standard for 3D printing of layered polymer composite using three polymers: HDPE, PVC, and ABS. The material properties of pure polymers and their blends were measured through tensile testing of injection-molded specimens. These properties were then used as input data in the FE model for the regions of pure polymers and their interfaces. An uncoupled thermo-mechanical analysis was performed, where a heat transfer analysis was realized first using elements birth (activation/deactivation) technique and a moving cylindrical volumetric heat source as a Fortran subroutine (DFLUX). With temperature input from thermal simulation, a mechanical analysis was carried out to deform the polymer composites along and across the print direction, i.e. under isostrain and isostress conditions, respectively. It was observed that the theoretical models existing in the literature underestimate the material properties as they do not consider the residual stresses developed during fabrication. The FE simulations predicted that the estimated material properties were 10 to 50% different from those calculated by the theoretical models, depending upon the residual stress level and the print direction. [ABSTRACT FROM AUTHOR]

Compared with traditional cement pastes, geopolymer pastes can effectively alleviate environmental and economic problems caused by the construction industry as they are characterised as low carbon dioxide materials, with energy reduced energy consumption and emissions. However, the mechanical properties of geopolymer pastes are greatly affected by the composition of the alkaline activators used in their preparation, and existing research results on this influence is not consistent. In this study, the effects of alkaline activators composed of varying concentrations of sodium hydroxide (NaOH) solution under standard curing conditions on the mechanical properties and material characteristics of geopolymer pastes made with fly ash and slag were investigated. Under standard curing conditions, the mechanical properties of the geopolymer pastes increased with an increase of sodium hydroxide solution (SHS) concentration in the alkaline activator. The use of alkaline activator with 16 M SHS led to the greatest flexural and compressive strengths of the geopolymer pastes at 28 days, reaching values of 5.43 MPa and 39.13 MPa, respectively. Increasing the SHS concentration in the alkaline activator promoted the production of gel products such as N-A-S-H, which formed a dense microstructure and led to higher mechanical properties. [ABSTRACT FROM AUTHOR]

Development of modified materials from dredged Sludge is one of the main ways to realize sludge utilization. In this paper, the dredged sludge resources utilization was researched by experiment, and the influence of the admixture type, dosage of the admixture, curing temperature curing age on the strength development, mineral component, reaction products and micromorphology of dredged sludge were studied by compressive strength test and XRD, TG/DSC and SEM technique respectively. The results show that dosage of admixture and the curing age of modifier has significant effects on the mechanical properties of the solidified sludge. The compressive strength of the specimen increases with the increase of the modifier dosage and curing age, and the maximum value of compressive strength is 8.3 MPa. The results of XRD, TG/DSC and SEM show that the flocculent geopolymer gel is formed by the reaction of clay minerals and the modifier, and the material structure is more compact and uniform. [ABSTRACT FROM AUTHOR]

Polyacrylamide (PAAm) hydrogels are widely adopted as 2D‐model soft substrates for investigating cell‐material interactions in a controlled in vitro environment. They offer facile synthesis, tunable physico‐chemical properties, diverse biofunctionalization routes, optical transparency, mouldability in a range of geometries and shapes, and compatibility with living cells. PAAm hydrogels can be engineered to reconstruct physiologically relevant biointerfaces, like cell‐matrix or cell–cell interfaces, featuring biochemical, mechanical, and topographical cues present in the extracellular environment. This Review provides a materials science perspective on PAAm material properties, fabrication, and modification strategies relevant to cell studies, highlighting their versatility and potential to address a wide range of biological questions. Current routes are presented to integrate cell‐instructive features, such as 2D patterns, 2.5D surface topographies, or mechanical stiffness gradients. Finally, the recent advances are emphasized toward dynamic PAAm hydrogels with on‐demand control over hydrogel properties as well as electrically conductive PAAm hydrogels for bioelectronics. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) technologies, particularly laser powder bed fusion (LPBF), are revolutionising the production of complex geometries and lightweight structures. Furthermore, LPBF allows to tailor the microstructure and resulting properties of metallic materials. This study focuses on titanium alloys, crucial for high-performance applications like aircraft components and medical implants. Although AM enables near-net-shape fabrication, many titanium parts still require machining to meet surface and dimensional standards. Titanium's challenging machinability is well-documented for cast and wrought alloys, but only less is known about additively manufactured variants. In this work, the machinability of an additively manufactured Ti-5Al-5V-5Mo-3Cr alloy (Ti-5553) is investigated, focusing on chip formation, cutting forces, and tool wear across different LPBF process parameters. Four LPBF parameter sets were validated, and results were compared to conventional wrought sample. The findings reveal significant variations in machinability linked to LPBF parameters. Specifically, the highest tool loads and wear were observed for samples produced with the highest energy density of E V = 37.0 J/mm3, likely due to α-phase precipitation. In contrast, samples with lower energy densities (<29.1 J/mm3) exhibited up to 100% longer tool life. Concluding, this study highlights how the machinability of Ti-based components can be significantly influenced by the LPBF processing parameters. [Display omitted] • Dense Ti-5553 samples were produced with high build rates using laser powder bed fusion. • By selecting appropriate process parameters, various tailored microstructure modifications were achieved. • LPBF parameters influence the microstructure and machinability, with higher energy densities increasing tool wear. • Tool life was significantly extended compared to Ti-5553 produced via conventional manufacturing methods. [ABSTRACT FROM AUTHOR]

Pyrolysis models are used in the fire science field to simulate the thermal decomposition of materials. These models require knowledge of the kinetic and thermodynamic parameters of an assumed reaction mechanism, and the thermophysical properties of the virgin material and product species. Standard test methods exist for measuring the thermal conductivity of nonreactive materials, but to date no suitable method exists that is compatible with contemporary pyrolysis models and is applicable to thermally reactive materials. In the present study, a modified methodology was presented and evaluated to address this need. The methodology involves a preliminary assessment of thermal stability, followed by a series of tests including: thermogravimetric analysis, differential scanning calorimetry, and laser flash analysis. Once a reaction mechanism has been identified, gram‐scale samples of the virgin and stable product species are isolated and independent measurements of thermal conductivity of those species are obtained. The methodology was applied to eucalyptus fiber hardboard, for which a complete set of property data for pyrolysis modeling was obtained. A pyrolysis experiment was then conducted, and that experiment was simulated using a pyrolysis model parameterized with the measured property data. Model predictions of the mass loss rate and temperature rise of a hardboard sample exposed to radiant heat flux of 35 and 60 kW m−2 were found to be a good match to measurements. These results demonstrate the suitability of the property data, the pyrolysis model, and the utility of this approach. This work will serve as a basis for property determination in future pyrolysis studies. [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]

The fatigue behavior of metal specimens is influenced by defects, material properties, and loading. This study aims to establish a multi-scale fatigue crack growth model that describes physically short crack (PSC) and long crack (LC) behavior. The model allows the calculation of crack growth rates for uniaxial loading at different stress ratios based on the material properties and specimen geometry. Furthermore, the model integrates the Gaussian distribution theory to consider material heterogeneity and the experimental measurement errors that cause fatigue scatter. The crack growth rate and fatigue life of metal specimens with different notch geometry were predicted. The curves generated by the multi-scale model were mainly consistent with the test data from the published literature at the PSC and LC stages. [ABSTRACT FROM AUTHOR]

This paper presents a systematic overview of the applications of RBP as a substitute for cement. Initially, the fundamental properties of RBP, including physical properties, chemical compositions, and morphology, are discussed. Subsequently, the effects of RBP on various aspects of cement-based materials, such as fresh properties, shrinkage behavior, hydration, microstructure, strength development, and durability, are thoroughly reviewed. The findings of this study reveal that waste brick powder exhibits pozzolanic activity and can be used to partially replace cement in concrete formulations. However, its relatively high water absorption and irregular shape increase the water demand and, thus, reduce the rheological properties. The incorporation of RBP with 10–20% or finer particle sizes can refine the pore structure and promote the formation of hydration products. However, replacements of RBP greater than 25% can lead to adverse effects on the mechanical properties, frost resistance, and carbonation resistance of cementitious composites. Therefore, to enhance the effectiveness of RBP, measures such as improving fineness, incorporating mineral admixtures, adjusting curing conditions, and applying nano- or chemical modifications are necessary. This study provides valuable technical support for promoting the sustainable preparation of construction materials, which holds important environmental and economic implications. [ABSTRACT FROM AUTHOR]

AbstractThis paper presents a novel capacitive microelectromechanical system comprising an array of elastomeric micro-pillars, which has been developed through the introduction of a coupled set of three nonlinear equations. The results have demonstrated that the new model utilizing polydimethylsiloxane is effective in reducing the actuation voltage, although this efficiency is reduced when the temperature is decreased. Moreover, the impact of frequency-dependent permittivity and its relaxation time on the vibrations of the moving electrode has been examined. The provided model and procedure can be utilized to analyze the effects of other materials on the system’s performance and to enhance its sensitivity. [ABSTRACT FROM AUTHOR]

In this study, an aging asphalt mixture was regenerated by a waste-based rejuvenator and cemented by solid waste-based solidification materials (SSMs). A splitting test, wheel tracking test, and three-point bending test were conducted to evaluate the properties of the regenerated asphalt mixture (RAM). The results reveal that the properties of the asphalt mixture were not diminished or were moderately enhanced by the 30% substitution of RAP. With the substitution of RAP to 100%, the splitting tensile strength, dynamic stability, and splitting strength ratio were decreased by 13%, 15%, and 5%, respectively. With the 100% substitution of SSMs for cement, the compressive strength, dynamic stability, flexural strain, and splitting strength ratios of the RAM were increased by 40%, 32%%, 14%, and 8%, respectively. The lightweight components can be supplemented, and low-temperature deformation and interlayer flowability can be improved by the incorporation of the rejuvenator. The generation of hydrated calcium silicate and ettringite for SSMs is greater than those of cement. The massive generation of ettringite has been observed to increase the solid phase volume by 120%, which may facilitate a more complete filling of the remaining pores in the RAM due to water evaporation. The regeneration and cement on green and the high performance of the rejuvenator and the SSM markedly enhanced RAM performance. [ABSTRACT FROM AUTHOR]

The pressure-preserving controller is the core part of deep in-situ pressure-preserving coring (IPPCoring) system, and its pressure-preserving capability is the key to IPP-Coring technology. To achieve a good understanding of the influence of mechanical properties of materials on the ultimate pressurebearing capability (UPB-Capability) of the pressure-preserving controller, the IPP-Coring experimental platform was developed to test the UPB-Capability of pressure-preserving controllers of four different materials. The experimental results show that the UPB-Capability of pressure-preserving controllers with different material varies greatly. A numerical model of the pressure-preserving controller was developed to study the influences of mechanical parameters of materials on the UPB-Capability of the pressurepreserving controller after the accuracy of the numerical model is verified by experiments. The results indicate that the yield strength (YS) and Poisson's ratio (PR) of the material have little effect on the UPBCapability of the pressure-preserving controller, whereas the elastic modulus (EM) of the material has a significant effect. A generalized model of the UPB-Capability of the pressure-preserving controller is developed to reveal the mechanism of the influence of material properties on the UPB-Capability of the pressure-preserving controllers. Considering these results, the future optimization direction of the pressure-preserving controller and material selection scheme in practical engineering applications of the pressure-preserving controller are suggested. [ABSTRACT FROM AUTHOR]

The microchannel plate (MCP) is an electron multiplier with millions of micro through-holes that must withstand strong vibrations and enormous shocks in spaceborne detectors. To ensure the reliability and robustness of the MCP in space applications, we proposed an equivalent mechanical model of the MCP to investigate its mechanical properties, since the direct creation of the finite element model using the finite element method (FEM) is not feasible. Then, we developed a test system to verify the effectiveness of the equivalent mechanical model. The results show that the error of harmonic response analysis and the test result is less than 10 %, which is acceptable. Finally, we conducted parametric studies of the MCPs and obtained the equivalent mechanical model of the MCPs with different geometric parameters. This study will help researchers to optimize the MCP for aerospace-grade detectors. [ABSTRACT FROM AUTHOR]

Implementation of existing stress–strain models for cold-formed steel requires the input of key material parameters determined from corner coupon tests on cold-formed portions. This paper proposes various approaches that can accurately describe the stress–strain responses of cold-formed steel by using corner material properties if known, or by using parent material properties and the corner geometry after cold-forming in the absence of corner material properties. First, a comprehensive database of coupon test results of cold-formed steel is assembled. A total of 483 corner coupon test results with 236 full stress–strain curves are collected from 31 sources, covering a large range of steel grades with nominal yield strength varying from 235 to 960 MPa. The applicability of existing empirical models for determination of the enhanced yield strength, ultimate strength, and ultimate strain is carefully evaluated. New predictive expressions for the required input parameters (namely, 0.01% or 0.05% proof stresses for the use of the two-stage Ramberg-Osgood model, and the strain hardening exponent for the use of one-stage material model) are subsequently derived. Prediction performances of the two-stage Ramberg-Osgood model and the one-stage material model are then evaluated against experimental stress–strain curves under different availabilities of primary material parameters. According to the proposed approaches, the minimum required input parameter to utilize these models is only the yield strength of cold-formed steel or, alternatively, the yield strength of the parent metal and corner geometry after cold-forming. The developed models are proved to be accurate in predicting the monotonic stress–strain response (up to the ultimate point) of cold-formed steel, and they are suitable for use in parametric studies and advanced modeling of cold-formed structures. [ABSTRACT FROM AUTHOR]

The processing of long glass fibre-reinforced thermoplastics results in considerable fibre damage, particularly during plasticising. By using thermoplastic foam injection moulding (FIM) with a constant blowing agent atmosphere, fibre damage during plasticisation can be reduced. This can be attributed to the reduction of the melt viscosity on the one hand and the influence of the melting behaviour on the other. Therefore, the influence of the FIM and the process parameters on the fibre length and the fibre length distribution are analysed and compared with the influence of the process parameters on the melt viscosity. [ABSTRACT FROM AUTHOR]

The research aimed to develop aluminum roofing sheets utilizing waste beverage cans, with a focus on minimizing costs and energy consumption. This initiative adhered to ASTM and ISO standard measures and procedures. Waste beverage cans underwent analysis and were compared with control sheets. Subsequently, they were manually melted, alloyed, and cast before being rolled to achieve the desired thickness and enhance specific properties. The resulting sheets were then corrugated. Upon analysis, the produced aluminum sheets exhibited promising characteristics. The corrosion penetration rate was measured at 0.045mm/yr, with a Rockwell hardness number of 55.1 and an indentation depth of 0.1498mm. Moreover, the average impact strength stood at 2.05, with a tensile strength of 71.69Mpa, yield strength of 25.65Mpa, and young modulus of 2596.43Mpa. The findings indicated a significant enhancement in the properties of the aluminum sheets manufactured from waste beverage cans. This underscored the feasibility of utilizing such cans in producing aluminum roofing sheets. Based on the results, it is recommended to further explore and refine the manufacturing process for aluminum roofing sheets from waste beverage cans. Additionally, continued adherence to ASTM and ISO standards is essential for ensuring product quality and reliability.

Power electronic conversion systems introduce different types of voltage stresses on high-voltage epoxy cast insulation in medium-frequency transformers (MFTs), which challenges the reliability of MFTs. The endurance of epoxy insulation at different voltages (AC, DC and pulse) and environmental (thermal and humidity) stresses was studied using encapsulated electrodes in the absence of partial discharge. To assess aging processes and select aging state indicators, various tests including AC breakdown strength (BDE), broadband dielectric spectroscopy, small-angle x-ray scattering (SAXS), Fourier-transform infrared spectroscopy and differential scanning calorimetry (DSC) were first conducted on aged flat samples. The increase of mesoscopic free volume from the SAXS result and local densification (physical aging) of epoxy network from the DSC result were both found. BDE is proved to be sensitive to various aging conditions and thus determined as a test method for encapsulated samples. It is found that the physical aging effect under thermal stress at early aging stages can cause a reversible increase in BDE compared to non-aged samples. This effect can be erased by coupled medium-low electrical stress during aging. In contrast, a sufficiently high electric field will deepen the physical aging extent. Occasional sample failures were observed simultaneously within this process. According to the SAXS and DSC results on flat samples, the failure of encapsulated samples is possibly attributed to the chain fracture around increased mesoscopic free volume during electron bombardment and microcracks generated by interfacial stress release during physical aging. At longer aging periods, the volumetric absorption and diffusion of chemical reactants (oxygen and water) in epoxy networks at high temperatures determines the eventual decrease in BDE, which can be accelerated by the electric field. Ages with different voltage types were gauged by the reduction of BDE compared to pure environmental stress. Bipolar pulses bring heavier aging effects than ACs at the same RMS value. However, the DC component has opposite effects on the BDE with and without thermal stress. [ABSTRACT FROM AUTHOR]

Floor‐tiling robotics are increasingly employed in on‐site building constructions owing to their remarkable benefits on rising working efficiency and reducing labor costs. In this study, a fluid–structure interaction (FSI) model of robotic tiling was established for the first time, construction parameters and adhesive properties were modified, and their influences on the quality of robotic floor‐tiling were systematically investigated by tracking the mechanical behaviors of tiles and adhesive during tiling and the interfacial defects after tiling. Results indicated that the established FSI model was feasible for assessing robotic tiling quality with a deviation of less than 2%. The adhesive extruded horizontally was evenly distributed in cylindrical strips. An increase in the number of extrusion pipes slightly improved the tiling quality. Compared with the leveling loads of compression and vertical vibration, shear vibration could effectively eliminate tile rebounding and enlarge the contact area of tile–adhesive by up to 135.85%. Moderate increases in the amplitude and frequency of shear vibration resulted in lower rebounding and larger contact areas. An appropriate increase of yield stress heightened tiling quality by keeping the extrusive appearance of the adhesive, increasing slightly tile rebounding and enlarging the contact area of tile–adhesive to 0.625 m2. As yield stress was excessively high, tremendous elastic deformations of adhesive led to remarkable tile rebounding and small contact areas of 0.375 m2. [ABSTRACT FROM AUTHOR]

Many insect species have found their way into ageing research as small and easy-to-keep model organisms. A major sign of ageing is the loss of locomotory functions due to neuronal disorders or tissue wear. Soft and pliable attachment pads on the tarsi of insects adapt to the substrate texture to maximize their real contact area and, thereby, generate attachment during locomotion. In the majority of stick insects, adhesive microstructures covering those pads support attachment. Stick insects do not molt again after reaching the imaginal stage; hence, the cuticle of their pads is subject to continuous ageing. This study aims to quantify how attachment ability changes with age in the stick insect Sungaya aeta Hennemann, 2023 and elucidate the age effects on the material and microstructure of the attachment apparatus. Attachment performance (adhesion and friction forces) on substrates with different roughnesses was compared between two different age groups, and the change of attachment performance was monitored extending over a larger time frame. Ageing effects on the morphology of the attachment pads and the autofluorescence of the cuticle were documented using light, scanning electron, and confocal laser scanning microscopy. The results show that both adhesion and friction forces decline with age. Deflation of the pads, scarring of the cuticle, and alteration of the autofluorescence, likely indicating stiffening of the cuticle, were observed to accumulate over time. This would reduce the attachment ability of the insect, as pads lose their pliant properties and cannot properly maintain sufficient contact area with the substrate.

AbstractThe simulation of the aortic valve (AV) remains challenging due to its geometric complexity and the multi-physics nature of the problem. In this study, we utilized COMSOL to establish a three-dimensional, three-leaflet AV fluid-structure interaction model and investigated the influence of material properties on the valve's mechanical behavior in a healthy state. The results indicated that variations in the aortic wall material model had a minor impact on AV hemodynamics. Additionally, while the linear elastic properties of the leaflets limit valve opening and closing, this material model allows for rapid assessment of AV performance within the range of material deformation. [ABSTRACT FROM AUTHOR]

Palm leaves are an important carrier for written heritage in southwest China, Tibet, and India. Due to the very nature of the material, many ancient palm leaf manuscripts are facing acidification and other types of degradation. Therefore, scientific research and conservation are of utmost importance. To study material properties and aging mechanisms of palm leaf manuscripts, their basic composition, physical and chemical properties, we studied infrared spectra, internal microstructure, and changes within the structure before and after aging of commonly used local talipot leaves. The results show that aging and deterioration of talipot leaves are mainly due to their acidic production process and high lignin content. The uneven distribution of longitudinal and transverse fiber bundles makes talipot leaves prone to longitudinal splitting. These findings provide important references for the conservation and long-term preservation of palm leaf manuscripts. [ABSTRACT FROM AUTHOR]

Light detection and ranging (LIDAR) sensors using a polarization-diverse receiver are able to capture polarimetric information about the target under measurement. We demonstrate this capability using a silicon photonic receiver architecture that enables this on a shot-by-shot basis, enabling polarization analysis nearly instantaneously in the point cloud, and then use this data to train a material classification neural network. Using this classifier, we show an accuracy of 85.4% for classifying plastic, wood, concrete, and coated aluminum. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have drawn significant attention due to their unique design and superior mechanical properties. Comprising 5–35 at% of five or more elements with similar atomic radii, HEAs exhibit high configurational entropy, resulting in single-phase solid solutions rather than intermetallic compounds. Additive manufacturing (AM), particularly direct energy deposition (DED), is effective for producing HEAs due to its rapid cooling rates, which ensure uniform microstructures and minimize defects. These alloys typically form face-centered cubic (FCC) or body-centered cubic (BCC) structures, contributing to their exceptional strength, hardness, and mechanical performance across various temperatures. However, FCC-structured HEAs often have low yield strengths, posing a challenge for structural applications. In this study, a Ni-Co-Fe-Cr-Al-Ti HEA was manufactured using the DED method. This study proposes that the addition of aluminum and titanium creates a γ + γ′ phase structure within a multicomponent FCC-HEA matrix, enhancing the thermal stability and coarsening the resistance and strength. The γ′ phase with an ordered FCC structure significantly improves the mechanical properties. Analysis confirmed the presence of the γ + γ′ structure and demonstrated the alloy's high tensile strength and microhardness. This approach underscores the potential of AM techniques in advancing HEA production for high-performance applications. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the mechanical behavior of resin composites and hybrid glass ionomer cement in class I adhesive dental restorations under loading and shrinkage conditions. Three CAD models of a mandibular first molar with class I cavities were created and restored with different techniques: a bi-layer of Equia Forte HT with Filtek One Bulk Fill Restorative composite (model A), a single layer of adhesive and Filtek One Bulk Fill Restorative (model B), and a single layer of Equia forte HT (model C). Each model was exported to computer-aided engineering software, and 3D finite element models were created. Models A and B exhibited a similar pattern of stress distribution along the enamel–restoration interface, with stress peaks of 12.5 MPa and 14 MPa observed in the enamel tissue. The sound tooth, B, and C models showed a similar trend along the interface between dentine and restoration. A stress peak of about 0.5 MPa was detected in the enamel of both the sound tooth and B models. Model C showed a reduced stress peak of about 1.2 MPa. A significant stress reduction in 4 mm deep class I cavities in lower molars was observed in models where non-shrinking dental filling materials, like the hybrid glass ionomer cement used in model C, were applied. Stress reduction was also achieved in model A, which employed a bi-layer technique with a shrinking polymeric filling material (bulk resin composite). Model C's performance closely resembled that of a sound tooth. [ABSTRACT FROM AUTHOR]

Three-dimensional printing is ideally suited to produce unique and complex shapes. In this study, the material properties of polysiloxanes, commonly named silicones, produced additively by two different methods, namely, multi-jet fusion (MJF) and material extrusion (ME) with liquid printing heads, are investigated. The chemical composition was compared via Fourier-transform infrared spectroscopy, evolved gas analysis mass spectrometry, pyrolysis gas chromatography coupled to mass spectrometry, and thermogravimetry (TGA). Density and low-temperature flexibility, mechanical properties and crosslink distance via freezing point depression were measured before and after post-treatment at elevated temperatures. The results show significant differences in the chemical composition, material properties, as well as surface quality of the tested products produced by the two manufacturing routes. Chemical analysis indicates that the investigated MJF materials contain acrylate moieties, possibly isobornyl acrylate linking branches. The hardness of the MJF samples is associated with crosslinking density. In the ashes after TGA, traces of phosphorus were found, which could originate from initiators or catalysts of the curing process. The ME materials contain fillers, most probably silica, that differ in their amount. It is possible that silica also plays a role in the processing to stabilize the extrusion strand. For the harder material, a higher crosslink density was found, which was supported also by the other tested properties. The MJF samples have smooth surfaces, while the ME samples show grooved surface structures typical for the material extrusion process. Post-treatment did not improve the material properties. In the MJF samples, significant color changes were observed. [ABSTRACT FROM AUTHOR]

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Lattice vibrations or phonons play an important role in determining material properties, including thermal conductivity. To model the phenomenon accurately and efficiently, the most important factors governing phonon physics need to be identified, for example, polarization branches. Research continues into many aspects of the fundamental physical processes involved in phonons and into possible applications of these processes in modern physics. One of the most interesting controversies in the thermal properties of graphene involves the importance of out-of-plane acoustic phonons. The need for clarity in understanding this importance dictates that the thermal conductivity of graphene should be evaluated in various circumstances. The nanoscale heat conduction properties of graphene are studied by iteratively solving the Boltzmann transport equation and rigorously treating the normal and Umklapp collisions in the frame of three-phonon interactions. This captures the mechanistic aspects of thermal conductivity by revealing what phonon branches are present. The thermal conductivity is evaluated in different crystallite sizes and at different frequencies and temperatures. The results indicated that out-of-plane acoustic phonons become increasingly important in the frame of three-phonon interactions. The out-of-plane acoustic branch dominates thermal transport whereas the other acoustic branches make small contributions. The importance of this branch is generally attributed to the high density of states and restrictions governing anharmonic effects. The three-phonon normal and Umklapp processes must be clearly accounted for and the contribution from optical branches is not negligible at higher temperatures. The results have implications in the quest for predictive and quantitative calculations of thermal conductivity. [ABSTRACT FROM AUTHOR]

Concrete production faces challenges due to the depletion of natural sand and the need for more sustainable practices. This study investigates the use of sugarcane bagasse ash (SCBA) and recycled polyethylene terephthalate (RPET) as partial replacements for cement and sand, respectively. SCBA was tested as a 5%, 10%, and 15% replacement by weight of cement, while RPET was used as a 5%, 10%, 15%, and 20% substitute for sand by volume. Concrete samples were cured in water for 7, 28, and 56 days. The mix with 5% SCBA and 10% RPET showed comparable compressive strength to conventional concrete and improved split tensile strength by 1.2% and 11.61% at 28 and 56 days, respectively. The compressive strength-to-weight ratio of this blend was less than 3% lower than conventional concrete. This combination also maintained similar water absorption and fire resistance characteristics. These results suggest that 5% SCBA and 10% RPET are effective in enhancing the sustainability of concrete while maintaining structural performance, contributing to more environmentally friendly construction practices. [ABSTRACT FROM AUTHOR]

This review comprehensively addresses the developments and applications of polymer materials in optoelectronics. Especially, this review introduces how the materials absorb, emit, and transfer charges, including the exciton–vibrational coupling, nonradiative and radiative processes, Förster Resonance Energy Transfer (FRET), and energy dynamics. Furthermore, it outlines charge trapping and recombination in the materials and draws the corresponding practical implications. The following section focuses on the practical application of organic materials in optoelectronics devices and highlights the detailed structure, operational principle, and performance metrics of organic photovoltaic cells (OPVs), organic light-emitting diodes (OLEDs), organic photodetectors, and organic transistors in detail. Finally, this study underscores the transformative impact of organic materials on the evolution of optoelectronics, providing a comprehensive understanding of their properties, mechanisms, and diverse applications that contribute to advancing innovative technologies in the field. [ABSTRACT FROM AUTHOR]

Cu–Be alloys are renowned for their exceptional mechanical and electrical properties, making them highly sought after for various industrial applications. This study presents a comprehensive approach to predicting the compositions of various types of Cu–Be alloys, integrating a Random Forest Regressor within a machine learning (ML) framework to analyze an extensive dataset of chemical and thermo-mechanical parameters. The research process incorporated data preprocessing, model training and validation, and robust analysis to discern feature significance. Cluster analysis was also conducted to illuminate the data's intrinsic groupings and to identify underlying metallurgical patterns. The model's predictive power was confirmed by high R2 values, indicative of its capability to capture and explain the variance in the dataset for both testing (R2 = 0.99375) and training (R2 = 0.99858). Distinct groupings within the alloy data were uncovered, revealing significant correlations between composition, processing conditions, and alloy properties. The findings underscore the potential of ML techniques in advancing the material design and optimization of Cu–Be alloys, providing valuable insights for the field of material science. [ABSTRACT FROM AUTHOR]

By combining the formability of injection-molded polymers with a wide range of metal options, metal injection molding (MIM) allows for manufacturing metallic components with small dimensions and complex geometries. However, steels produced through this process often exhibit higher porosity compared to conventional methods. This article aims to fill this gap by developing a thermochemical oxynitrocarburizing treatment cycle applied to the austenitic stainless steel Catamold 316L. The developed treatment analyzes the diffusion kinetics, mechanical properties, and metallurgical behavior. The oxynitrocarburizing treatment was carried out at a temperature of 570 °C for varying durations of 30, 60, and 120 min. The findings showed that surface microhardness significantly increased, and corrosion resistance improved due to the ceramic behavior of the Epsolon composite and the formation of magnetite, compared to the sintered material. The study reveals a substantial rise in residual compressive stresses of up to − 2790 MPa on the sample surface. The residual stress values and the elevated surface microhardness are highly beneficial for improving the tribological properties of Catamold 316L steel produced by the MIM process. The study suggests that using ionic oxynitrocarburizing in salt baths presents an alternative to plasma processes for treating Catamold 316L steel, providing improved diffusion of nitrogen and carbon. [ABSTRACT FROM AUTHOR]

The terahertz (THz) region of the electromagnetic spectrum, spanning from 0.1 to 10 THz, offers unique opportunities for imaging, spectroscopy, and communication applications. However, the potential of THz technologies has been limited by the availability of efficient and versatile THz emitters. Spintronic THz emitters (STEs), leveraging the ultrafast dynamics of electron spins in magnetic materials, have emerged as a promising solution to this challenge. STEs offer significant advantages, including broad bandwidth, high power output, and room-temperature operation, positioning them at the forefront of THz technology development. Despite these advances, understanding the operational principles and improving the performance of STEs remain areas of active research. This review focuses on the theoretical models that describe the behavior of STEs, aiming to provide a comprehensive overview of the underlying physics and suggest directions for future enhancements. Through a detailed examination of these models, the review seeks to clarify the basics of the physics driving STE performance and highlight innovative strategies for their optimization and application expansion. [ABSTRACT FROM AUTHOR]

The deep-sea connector is a signal transmission equipment that ensures the normal operation of marine equipment, and the normal operation of the deep-sea connector largely depends on the sealing performance of the O-ring. Therefore, the problem that the deep-sea high- pressure environment causing O-ring deformation and seriously affecting the sealing performance of O-ring was analyzed. Firstly, based on the theory of structural deformation, the influence of environmental pressure on the deformation of the seal structure and the compression amount of the O-ring was theoretically analyzed. Then a nonlinear dynamic seal model of the O-ring was established by the finite element method, the influence of model grid division on the accuracy of the simulation results was analyzed and studied, and the relationship curve between the structural deformation and environmental pressure was analyzed. Finally, the effects of material properties, environmental pressure and sealing structure size on the performance of dynamic seals were studied and analyzed. The research results show that when the actual value of the grid is 47 745, and the measured value is 21 685, 37 934 and 50 707, the error of the simulation results is less than 2% . The curve trends of the deformation of seal structure and the compression of O-ring are basically consistent with the theoretical values. The change of material properties and environmental pressure will affect the dynamic sealing performance. In the sealing structure size, increasing the groove fillet radius can enhance the dynamic sealing performance of the O-ring. The research results can provide reference and theoretical support for the design and optimization of O-ring under deep-sea high-pressure environment. [ABSTRACT FROM AUTHOR]

Mulch was prepared using composted sugarcane leaves, with polyvinyl alcohol and cationic starch as adhesives, through compression molding. The study aimed to investigate the effects of different adhesives on the mechanical properties, thermal oxidative degradation performance, and biodegradability of the covering materials. The results indicated that, when the adhesive dosage was consistent, cover material A, which utilized polyvinyl alcohol as the adhesive, exhibited higher tensile strength and elongation at break compared to cover material B, which employed a blend of polyvinyl alcohol and cationic starch. Specifically, at an adhesive dosage of 20%, cover material A achieved a tensile strength of 0.46 MPa and an elongation at break of 7.72%, representing the highest values among all experimental groups. There was minimal disparity in the thermal oxidative degradation performance between materials prepared with either adhesive; however, a higher quantity of adhesive led to decreased biodegradability performance. After being buried in soil for 120 days, the degradation exceeded 40% for both materials, resulting in loss of their original shape and strength properties. In conclusion, while sugarcane leaves-based biodegradable materials demonstrate favorable degradation performance, further enhancements are necessary to improve their mechanical properties. These materials have potential applications as substitutes for plastic mulch. [ABSTRACT FROM AUTHOR]

Vinyl polymers, crucial in contemporary contact lens design, present unique attributes with promising implications for vision correction. This comprehensive review navigates the trajectory and future trajectories of vinyl polymer‐based contact lenses. The introduction underscores the vital role of contact lenses in vision correction and positions vinyl polymers as ideal materials due to their exceptional properties. Delving into material specifics—high oxygen permeability, optical clarity, surface wettability, and mechanical strength—the analysis emphasizes their influence on corneal health, comfort, and durability. The versatility of manufacturing techniques, encompassing spin casting, molding processes, polymerization, and surface modification, underscores their feasibility in crafting high‐quality lenses. Examining clinical applications, encompassing daily disposables, extended wear, silicone hydrogel, and specialty lenses, alongside biocompatibility assessments and user feedback, provides a nuanced understanding of vinyl polymer‐based lens effectiveness. The article candidly addresses challenges—dehydration, deposits, mechanical stability, and durability—alongside regulatory considerations. Future prospects involve novel formulations, smart materials, bioinspired designs, and noninvasive technologies to amplify comfort and performance. In conclusion, this review distills progress, acknowledges challenges, and charts a sanguine course for vinyl polymer materials in advancing contact lens design, envisioning a future marked by enhanced vision correction technologies. [ABSTRACT FROM AUTHOR]

Purpose: Additive manufacturing (AM) of duplex stainless steels (DSS) is still challenging in terms of simultaneously generating structures with high build quality and adequate functional properties. This study aims to investigate comprehensive process-material-property relationships resulting from both laser-directed energy deposition (DED-LB/M) and laser powder bed fusion (PBF-LB/M) of DSS 1.4462 in as-built (AB) and subsequent heat-treated (HT) states. Design/methodology/approach: Cuboid specimens made of DSS 1.4462 were generated using both AM processes. Porosity and microstructure analyses, magnetic-inductive ferrite and Vickers hardness measurements, tensile and Charpy impacts tests, fracture analysis, critical pitting corrosion temperature measurements and Huey tests were performed on specimens in the AB and HT states. Findings: Correlations between the microstructural aspects and the resulting functional properties (mechanical properties and corrosion resistance) were demonstrated and compared. The mechanical properties of DED-LB/M specimens in both material conditions fulfilled the alloy specifications of 1.4462. Owing to the low ductility and toughness of PBF-LB/M specimens in the AB state, a post-process heat treatment was required to exceed the minimum alloy specification limits. Furthermore, the homogenization heat treatment significantly improved the corrosion resistance of DED- and PBF-processed 1.4462. Originality/value: This study fulfills the need to investigate the complex relationships between process characteristics and the resulting material properties of additively manufactured DSS. [ABSTRACT FROM AUTHOR]

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Recent studies show that zinc oxide (ZnO) nanostructures have promising potential as an absorbing material. In order to improve the optoelectronic properties of the initial system, this paper considers the process of adsorbing multilayer graphene-like ZnO onto a Si (111) surface. The density of electron states for two- and three-layer graphene-like zinc oxide on the Si (111) surface was obtained using the Vienna ab-initio simulation package by the DFT method. A computer model of graphene-like Zinc oxide on a Si (111)-surface was created using the DFT+U approach. One-, two- and three-plane-thick graphene-zinc oxide were deposited on the substrate. An isolated cluster of Zn3O3 was also considered. The compatibility of g-ZnO with the S (100) substrate was tested, and the energetics of deposition were calculated. This study demonstrates that, regardless of the possible configuration of the adsorbing layers, the Si/ZnO structure remains stable at the interface. Calculations indicate that, in combination with lower formation energies, wurtzite-type structures turn out to be more stable and, compared to sphalerite-type structures, wurtzite-type structures form longer interlayers and shorter interplanar distances. It has been shown that during the deposition of the third layer, the growth of a wurtzite-type structure becomes exothermic. Thus, these findings suggest a predictable relationship between the application method and the number of layers, implying that the synthesis process can be modified. Consequently, we believe that such interfaces can be obtained through experimental synthesis. [ABSTRACT FROM AUTHOR]

Fibres in different textile forms (woven, knitted, stitched, and non-crimp) are used to reinforce composites for multifaced applications, including automotive, aerospace, marine, rail, energy, construction, and defence sectors. Textile fabric-based fibre reinforcements for composites possess some outstanding features, such as good dimensional stability, subtle conformability, deep draw moldability/processability, lightweightness, high strength and stiffness, and low cost. The greatest advantage of textile fibre-reinforced composites is the freedom to tailor their strength and stiffness properties for specific applications. Therefore, the design of composites involves defining the fabric geometry, stacking sequence, and orientation of fibres to optimise the system. Compared to knitted, stitched, and non-crimp fabrics, woven fabric-based fibre-reinforced composites are widely used in the industry. The properties of woven fabric-reinforced composites depend on several factors, such as types of fibre, compositions, polymeric matrices, and fibre/matrix interfacial strength. Some of the advantages are reduced preforming process steps, good impact and delamination resistance, and thermo-mechanical properties. This review has been written to provide detailed information and discussions, including the fabrication processes, relationship between fabric structure and composite properties, and morphological characteristics encompassing the current state-of-the-art in woven fabrics for composite reinforcement. [ABSTRACT FROM AUTHOR]

To improve the machinability properties of CuZn-alloys, these are alloyed with the element lead. Due to its toxicity, a variety of legislative initiatives aim to reduce the lead content in CuZn-alloys, which results in critical machinability problems and a reduction in the productivity of machining processes. Basically, there are two ways to solve the critical machinability problems when machining lead-free CuZn-alloys: optimizing the machinability of lead-free materials on the material side or adapting the processes and the respective process parameters. In this study, the focus is on material-side machinability optimization by investigating the influence of a targeted variation in the process chain in the material production route. To evaluate the influence of the material production route, the brass alloy CuZn40 (CW509L) was produced in four variants by varying the degree of work hardening and the use of heat treatments, and all four variants were evaluated in terms of their machinability. To evaluate the machinability, the cutting force components, the chip temperature, the chip formation, and the chip shape were analyzed. Clear influences of the material production route were identified, particularly with regard to the chip formation mechanisms and the resulting chip shape. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM), a quickly changing field, is reshaping industries by producing novel and customized materials quickly and efficiently. AM deviates from conventional subtractive processes by enabling layer-by-layer production of products with computer-aided design software. This process offers unique advantages for niche applications, such as metamaterial properties. Numerous industries have adopted this adaptable and aesthetically pleasing technology. For 3D printing, nylon, known for its strength, durability, and flexibility, has become the material of choice, especially when creating complex objects. Though it suffers from some difficulties, such as stretching and shrinking, as the most common AM method for nylon, material extrusion takes advantage of its superior mechanical properties and reliability. The processes, morphological traits, and mechanical properties of the AM of nylon and nylon composite materials are all covered in this thorough review, which methodically focuses on the body of current research. Tensile, flexural strength, and hardness are the main mechanical properties explored in this review, considering subtleties found in previous research. The paper ends with a research analysis viewpoint, pointing out managerial and theoretical gaps based on the body of literature and advocating for more studies to improve AM procedures. This succinct but comprehensive review offers insightful guidance on overcoming obstacles and leveraging advances in AM materials. [ABSTRACT FROM AUTHOR]

Abstract Polyacrylamide (PAAm) hydrogels are widely adopted as 2D‐model soft substrates for investigating cell‐material interactions in a controlled in vitro environment. They offer facile synthesis, tunable physico‐chemical properties, diverse biofunctionalization routes, optical transparency, mouldability in a range of geometries and shapes, and compatibility with living cells. PAAm hydrogels can be engineered to reconstruct physiologically relevant biointerfaces, like cell‐matrix or cell–cell interfaces, featuring biochemical, mechanical, and topographical cues present in the extracellular environment. This Review provides a materials science perspective on PAAm material properties, fabrication, and modification strategies relevant to cell studies, highlighting their versatility and potential to address a wide range of biological questions. Current routes are presented to integrate cell‐instructive features, such as 2D patterns, 2.5D surface topographies, or mechanical stiffness gradients. Finally, the recent advances are emphasized toward dynamic PAAm hydrogels with on‐demand control over hydrogel properties as well as electrically conductive PAAm hydrogels for bioelectronics.

The current study shows the application of 3D printing methods for structural testing. The primary goal of the experiments was to facilitate mechanical testing using polyamide 6 (Nylon) augmented with glass fibres, or PA6-GF. The assessment aims to demonstrate the efficacy of 3D printing techniques in preparing structural specimens and determining the material’s suitability for mechanical testing. This approach has the potential to optimize the process, save time, and reduce operational costs, including technician time and workload. the PA6-GF was tested to assess stress-strain curves and ultimate capacity before being employed as a construction material in the structural laboratory. Test results had shown a modulus of elasticity for the PA6-GF in the range of 992 MPa and 2040 MPa and a Poisson’s ratio in the range of 0.34–0.40. The application of 3D printing techniques and PA6-GF were successfully applied to overcome the limitation of commercially available stands to support steel meshes for the construction of a bridge deck to a reduced scale of 1–6. The use of PA6-GF material provided adequate mechanical properties and helped in reducing both construction time and cost on the order of 14 % and 7 %, respectively. These results indicates that this technology is a promising tool to enhance both construction processes and construction quality.

In this experiment, a general purpose BP neural network (BP) based on genetic algorithm (GA) was developed for predicting fiber properties. The experiment is based on the breaking force of cotton fibers, and the controlled variable method is used for sampling test to collect 878 datasets containing four eigenvalues. The first 850 items of this dataset were then utilized to train the designed BP, and the remaining 28 items were evaluated for error. Next, the model is parameterized using a genetic algorithm to reduce the overall network size, thus optimizing the fit. Finally, the improved model was evaluated using the same dataset. The results were obtained: the MAPE was reduced from 10.94% to 3.7869%, the MAE was reduced from 0.39586 to 0.14584, and the MSE was reduced from 0.32161 to 0.05201. The results show that this GA-BP has better results for nonlinear fitting, and it can make a better correspondence to the outliers in the dataset, and also produces a smaller error in the fitting results, the Overall, the method is effective.

This study focuses on the delamination and characterization of different loadings and temperature conditions of polyvinyl chloride (PVC)-coated polyurethane (PUR) foam component layers commonly used in bus dashboards. The method was developed through mechanical and thermal tests.The study involves the examination of primer and no primer PVC-coated PUR components using SEM (Scanning Electron Microscope), tensile-compression, three-point bending, primer characterization, peel, PUR material thermal expansion, and thermal tests. Physical and material tests were conducted to determine the mechanical properties of PVC and PUR foam and the material properties of the primer. Fourier transform infrared spectroscopy (FTIR) analysis was also conducted to identify the functional groups present in the PVC, PUR, and primer materials, helping to understand the material interactions.Some tests produced the expected results, while others did not. The primer characterization and three-point bending tests were unsuccessful due to sample foam breakage. However, tensile-compression tests, peel tests, thermal expansion tests, and thermal tests yielded the desired outcomes. During thermal testing of primed samples, it was observed that the samples shortened and bent as the primer material melted and began to separate from the PVC and PUR layers. This bending and swelling were attributed to the difference in thermal expansion coefficients between the melting primer material and the PVC and PUR layers. The results demonstrate that PVC-coated PUR components can be effectively separated, and they also highlight opportunities for design modifications to improve the durability of bus dashboards.

This study investigates the dynamic interplay between carbon levels and surface area variations on mild steel strength during the rolling process. Focused on understanding the nuanced relationship between these factors and steel durability, the research adopts a systematic approach. Controlled adjustments in carbon levels and surface area variations are employed to assess their impact on the structural integrity and tensile strength of mild steel. Through rigorous analysis and measurement, this study aims to unveil the intricate connections between carbon content, surface area alterations, and steel strength, offering critical insights for optimizing rolling processes in industrial settings. The experimental works have been conducted with carbon levels variations and surface area variations. The samples were tested in two different laboratories, however, the results of two laboratories are almost similar. The higher carbon content increases strength and yield strength varies with different carbon level and surface area. The surface area variations are affected the mechanical properties of mild steel. The maximum stress recorded was 700 MPa and the breaking point observed at 540 MPa. The findings aspire to contribute significantly to refining manufacturing techniques and developing more resilient steel products, thereby advancing our comprehension of material behavior in mechanical applications.