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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]

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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]

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]

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]

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]

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 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 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]

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 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]

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]

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]

Copyright of Automotive Engineer (1674-6546) is the property of Auto Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Restaurator is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

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]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Copyright of Journal of Mechanical & Electrical Engineering is the property of Mechanical & Electrical Engineering Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

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]

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]

This paper defines the tensile properties of a successfully worn 3D-printed transtibial socket. The socket was printed from a proprietary polypropylene filament and FDM 3D-printing process. Fused disposition modeling involves producing successive cross-sectional layers on top of one another and welding them together. Because of this, a notch is formed between the printed layers. As part of this investigation, tensile test specimens were die-cut perpendicular to the material direction and tested according to ASTM D638—Standard Test Method for Tensile Properties of Plastics. From the measured load–elongation data, stress–strain curves and the corresponding material properties were determined, including modulus of elasticity E, Poisson's ratio ν, yield strength Sy, and ultimate strength Su. The average values for each of these material properties were 955 MPa, 0.35, 11.4 MPa, and 16.3 MPa, respectively. In addition to defining tensile properties, this work demonstrated a viable methodology for characterizing the as-built material behavior of 3D-printed sockets. [ABSTRACT FROM AUTHOR]

The development of urbanization and the resulting expansion of residential and transport infrastructures pose new challenges related to ensuring comfort for city dwellers. The emission of transport vibrations and household noise reduces the quality of life in the city. To counteract this unfavorable phenomenon, vibration isolation is widely used to reduce the propagation of vibrations and noise. A proper selection of vibration isolation is necessary to ensure comfort. This selection can be made based on a deep understanding of the material parameters of the vibration isolation used. This mainly includes dynamic stiffness and damping. This article presents a comparison of the method for testing dynamic stiffness and damping using a single degree of freedom (SDOF) system and the method using image processing, which involves tracking the movement of a free-falling steel ball onto a sample of the tested material. Rubber granules, rubber granules with rubber fibers, and rebound polyurethanes were selected for testing. Strong correlations were found between the relative indentation and dynamic stiffness (at 10–60 MN/m3) and the relative rebound and damping (for 6–12%). Additionally, a very strong relationship was determined between the density and fraction of the critical damping factor/dynamic stiffness. The relative indentation and relative rebound measurement methods can be used as an alternative method to measure the dynamic stiffness and critical damping factor, respectively. [ABSTRACT FROM AUTHOR]

Car manufacturers are currently challenged with increasing the sustainability of their products and production to comply with sustainability requirements and legislation. One way to enhance product sustainability is by reducing the carbon footprint of fossil-based plastic parts. Particle foams are a promising solution to achieve the goal of using lightweight parts with minimal material input. Ongoing developments involve the use of expanded particle foam beads made from engineering plastics such as polyamide (EPA). To achieve this, a simulated life cycle was carried out on virgin EPA, including mechanical recycling. The virgin material was processed into specimens using a steam-free method. One series was artificially aged to replicate automotive life cycle stresses, while the other series was not. The mechanical recycling and re-foaming of the minipellets were then carried out, resulting in an EPA particle foam with 100% recycled content. Finally, the thermal and chemical material properties were comparatively analysed. The study shows that the recycled EPA beads underwent polymer degradation during the simulated life cycle, as evidenced by their material properties. For instance, the recycled beads showed a more heterogeneous molecular weight distribution (an increase in PDI from two to three), contained carbonyl groups, and exhibited an increase in the degree of crystallization from approximately 24% to 36%. [ABSTRACT FROM AUTHOR]

Permeable-pavement design methodologies can improve the hydrologic and therefore the environmental benefits of rural and urban roadway systems. By contrast, conventional impervious pavements perturb the hydrologic cycle, altering the relationship between the rainfall loading and runoff response. Impervious pavements create a hydraulically conductive interface for the transport of traffic-generated chemicals and particulate matter (PM), deleteriously impacting their proximate environments. Permeable-pavement systems are countermeasures to mitigate hydrologic, chemical, and PM impacts. However, permeable pavements are not always equally implementable due to costs, PM loadings, and design constraints. A potential solution to facilitate environmental benefits while meeting the traffic load capacity is the combination of two filtration systems placed at the pavement shoulders and/or pedestrian sidewalks: a bituminous-pavement open-graded friction course (BPFC) and an aggregate-filled infiltration trench. This solution is presented in this manuscript together with the methodological framework and the first results of the investigations into designing and validating such a combined system. The research was conducted at the laboratories of the Polytechnic University of Bari and the University of Florida, while an operational and full-scale physical model was constructed in Bari, Italy. The first results presented characterize the PM deposition on public roads based on granulometry (particle size distributions (PSDs) and particle number densities (PNDs)). Samples (n = 16) were collected and analyzed at eight different sites with different land uses, traffic, and pavements from different cities (Bari and Taranto, Italy). The PM analysis showed similar distributions (PSDs and PNDs), except for two samples. The gravimetric-based PSDs of the PM had granulometric distributions in the sand-size range. In contrast, the PNDs, modeled by a Power Law Model (PLM) (R2 ≥ 0.92), illustrated an exponentially increasing number of particles in the fine silt and clay-size range, representing less than 10% of the PSD mass. Moreover, the results indicate that PM sourced from permeable-pavement systems has differing impacts on the pavement service life. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This comprehensive literature review delves into the application of Scheffe's Simplex Lattice Model for optimizing cement concrete mixtures, with a particular emphasis on its impact on material properties and sustainability. The review meticulously outlines the principles, historical context, and advantages of Scheffe's model, providing a nuanced understanding of its significance. Comparative analyses with traditional and alternative optimization techniques in concrete mix design illuminate the distinct advantages of statistical methods, especially Scheffe's model. The review critically examines the challenges and limitations associated with applying Scheffe's model, addressing issues related to the complexity of concrete mixtures and computational demands. Potential avenues for improvement are explored, suggesting refinements to handle non-linearity, incorporate advanced optimization algorithms, and streamline computational requirements. Additionally, the review highlights emerging trends in statistical modeling for concrete mixture optimization, such as the integration of machine learning and data-driven approaches, signaling the evolving landscape of concrete technology. In conclusion, the literature underscores Scheffe's Simplex Lattice Model as a valuable and versatile tool with far-reaching implications for the advancement of concrete mixture design methodologies. The call to action encourages ongoing research and development to refine the model, explore emerging trends, and address practical challenges, positioning Scheffe's model as a cornerstone in the pursuit of sustainable, resilient, and high-performance concrete materials. [ABSTRACT FROM AUTHOR]

In the bridge structure, the main bearing element is the spans, which are directly subject to random and continuous loads, environmental influences, ageing, etc. These factors are easy to lead to material deterioration. Therefore, this study proposes a novel approach to investigate the mechanical properties of the material. The span of the bridge is the selected structure for investigation. This study focuses on the general evaluation of mechanical factors consistent with reality, so the following main factors are to be carried out. First, the viscoelastic model of material will be applied to set up and solve the governing differential equation of the beams with material characteristics involving the elastic modulus (E) and the viscous coefficient (C). The viscoelastic model is different from the traditional elastic model due to its non-linearity, reflecting the actual state of the structure. Second, the random vibration signal-based Loss Factor function (LF) calculation using the Power Spectral Density (PSD) to detect changes in structures. LF is a feature representing changes in material properties, including elasticity and viscosity, and is suitable for many types of bridge structures. Also, the paper uses Cubic Interpolation (CI) to generate a surface representing the LF distribution. This interpolation results in surfaces with respect to the LF values distributed by frequencies and spectral amplitudes. Finally, the LF distribution-based material investigation using Convolutional Neural Network (CNN) is proposed with high performance and accuracy. This study applies the proposed method to several bridges in Ho Chi Minh City, Vietnam. It demonstrates that LF is highly suitable for bridge health monitoring. [ABSTRACT FROM AUTHOR]

The purpose of this study is to determine the material properties of CFRP composites in the form of a fabric for the construction of racing car bodywork. This work focused on the determination of the strength and tribological properties as well as investigating the effects of the operating environment on the developed material. Three material variants, differing in the number of layers used to produce the reinforcement, were used in this study. The tests were carried out on two-/three-/four-layer sheets produced by infusion. Due to the later use of the tested composites for the sheathing of a racing car, the results obtained were analysed in terms of the most favourable strength properties while keeping the weight as low as possible. In this study, the hardness, impact strength, and tensile and bending stresses of the developed composites were examined. In addition to the strength properties, the density, the effects of immersion in water, and the composite's resistance to staining and friction in the presence of aggressive media were also checked. The structure and the breakthroughs resulting from the strength tests were observed using a stereoscopic microscope. The material's resistance to sunlight and UVB was also tested. [ABSTRACT FROM AUTHOR]

Copyright of Bauphysik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface topography is an important factor in evaluating surface integrity and surface roughness of the processed material to ensure the processing quality and shorten the processing cycle. In this paper, a prediction model of milling surface quality, considering the influence of the machine tool factors, the milling tool factors, and the workpiece material factors, is proposed. Based on the dynamic path trajectory, the model takes first the imbalance of the machine tool spindle as a critical machine factor affecting the tool-workpiece displacement and the surface topography. Then, the tool parameters are predicted using a backpropagation neural network (BPNN); the tool wear behaviors are taken into account. To expand the different workpiece application, material properties, such as the elastoplasticity, are introduced to improve the prediction accuracy. Thus, a series of experiments with various machine tools, milling tools, materials, and processing parameters validate the surface quality prediction model based on machine-tool-material interactions. Finally, the results demonstrate that the simulated outcomes accord well with the experiment; the error rate of the best result is only 3.60%, and the average error rate is 9.6%. [ABSTRACT FROM AUTHOR]

The increasing diversity of materials creates many possibilities and constraints that designers have to consider when selecting materials for projects. While the literature has investigated materials selection in engineering, product, and architectural design, knowledge is still lacking in interior design. Accordingly, this study focused on interior finishing materials with three objectives: (1) explore the determinants of materials selection in interior design, and within the residential design context, (2) identify designers' finishing material preferences and selection criteria for floors, walls, and ceilings; (3) investigate designers' criteria prioritizations while selecting materials. For this we conducted one-to-one interviews with architects and interior designers specializing in residential spaces. We first explored their material selection considerations in general. Second, we documented their material designations in residential project entry halls they had designed along with their selection criteria. Third, we presented an entry hall of a residential space for them to choose the materials while we questioned them about their materials selection priorities. The results reveal that the main determinants of materials selection include material-related, project-related, and designer-related factors. Moreover, materials choices and selection criteria vary between surfaces in space. Finally, the designers give the most priority to sensorial properties and the least to ecological properties. These findings expand our knowledge about materials in interior design, enhance the knowledge base for materials education, and have implications for designers and manufacturers regarding selecting and designing finishing materials. [ABSTRACT FROM AUTHOR]

Evaluating the technical conditions and performance for historic bridges is essential to ensure their structural safety and determine their need for strengthening. This study investigates the first railway steel bridge built in China in 1894, which is listed as a national preservation unit and industrial heritage site. The bridge was not only exposed to years of weather change but also suffered a geological disaster in 1976. In addition, the surroundings have changed, including the construction of new railway lines and scenic areas. Thus, it is imperative to evaluate its technical conditions and performance, particularly its material properties. To this end, evaluation procedures were formulated. First, the material composition, properties, and grades of steel were determined by microstructural analysis: the grade of nonmetallic inclusions in steel was determined by metallographic analysis; the corrosion rate of steel was obtained by electrochemical analysis; and the crystal type, size, element product of the corrosion layer, as well as the fracture type of the steel, were analyzed by phase composition and elemental analysis. Next, the static performance indices of the steel were obtained by mechanical property tests: the hardness value of the steel was obtained from hardness test; the yield and tensile strengths of the steel were obtained from tensile tests; and the fatigue properties of the steel were analyzed through fatigue tests. The S-N curve of the steel was determined by fitting the tested data. This study provides a reference for the evaluation of the technical conditions and performance of historic bridges. [ABSTRACT FROM AUTHOR]

A supercritical suspended abrasive water jet with dual inputs of pressure and heat is proposed to improve the cutting performance of the conventional suspended abrasive water jet in deep-sea environments. The paper studies the flow and kinetic characteristics of the supercritical suspended abrasive water jet. The CFD simulation method is proposed to investigate these characteristics by integrating a programmed database of supercritical water material properties with Ansys Fluent. The simulation and comparison show that abrasive particle density, abrasive particle size, inlet pressure, and water temperature affect the acceleration process of the abrasive particles. At the nozzle outlet, the velocity of the abrasive particles reaches over 95% of the supercritical water velocity. With the proposed supercritical abrasive water jet, the jet velocity is increased by 192.2% to 402.40 m/s compared to the conventional suspended abrasive water jet, reducing the amount of water used by 67.7% at a specified temperature of 773.15 K. Correspondingly, the medium kinetic energy is increased by 177.7% and the medium kinetic energy ratio is 2.78. The particle kinetic energy is increased by 723.2% and the particle kinetic energy ratio is 8.23. [ABSTRACT FROM AUTHOR]

T oday, the building materials form the historical buildings are being exposed to various deteriorations increasingly due to different causes. Many historical masonry constructions in the world are on the edge of extinction due to the increasing frequency and changing models of material deterioration. The materials as close as possible to the original materials in terms of their chemical compositions and physical properties are required in the reconstruction and maintenance of the buildings that have historical importance. In addition, the properties of the materials used in the historical buildings are generally not known with a sufficient accuracy. This causes misapplications in case of emergencies, and also may lead to future potential greater damages on the building. The lack of data regarding the engineering properties of these buildings causes long-term damages on the buildings due to inappropriate conservation methods and materials. Therefore, it is necessary to investigate the properties of certain materials for application in the renewal of the historical buildings. Within this context, in this study the construction materials of Mardin Castle, which is located in Mardin Province, Turkey and existing for centuries as the symbol of the city, are investigated and its properties are reached. Experimental research methods were used in the study. Primarily, the castle structure was examined on-site by field study and sampling was carried out from the areas determined. The samples were analyzed via various spectroscopic and geophysical methods, and various findings were achieved. Relatively variable and high levels of salinization were determined in the findings regarding the average values in stone samples of Mardin Castle's Fortification Walls. Results of the research document the conservation status regarding Mardin Castle and provide an experimental base and also a theoretical support for the conservation of historical buildings in Turkey; and present indicative suggestions to establish conservation schemes of the historical buildings [ABSTRACT FROM AUTHOR]

For the 3D STAR project and 3D printing purposes, a special fine-grained cement mixture from locally available raw materials was developed. The reason for the development of the custom mixture was the possibility of arbitrary optimization of the developed mixture at any stage of the project and for any type of application. Mix design, printing head and the entire system from mixing to extrusion was the subject of research and development for this project. It was therefore necessary to address both issues in parallel and to respond in both sectors to the realities arising from the partial results of the different groups involved in the development. [ABSTRACT FROM AUTHOR]

Sustainable construction is a rapidly growing area of research focused on using industrial waste to replace Portland cement in concrete. This approach not only reduces CO2 emissions from cement production but also serves as an effective way to diminish the environmental impact of concrete production. This study aims to investigate the properties of Coal Bottom Ash (CBA) after undergoing two different treatments: flotation and burning. It also evaluates the impact of CBA as a cement replacement in concrete with different replacement percentages (5%, 10%, 15%, and 20%). Chemical analysis of CBA has revealed that it can be classified as a pozzolanic material due to its high content of silicates, aluminates, and iron oxides. The microstructure of CBA showed a porous, angular, and irregular surface with many voids. The findings of this study revealed that the optimum mix was 10% CBA, resulting in a 2% increase in compressive strength compared to the control mix after 56 days of curing. Additionally, the study evaluated the effects of sulfate and chloride on concrete. It was found that the mix with the burning treatment showed an overall increase in strength, while the flotation treatment did not reach the control mix's strength in any of the curing periods. Furthermore, the results demonstrated that CBA has significant potential as a cement replacement material, and the burning treatment showed improvement in concrete's overall properties compared to the raw material in terms of mechanical and chemical properties while reducing greenhouse gas emissions and enhancing the environment. [ABSTRACT FROM AUTHOR]