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Purpose: The purpose of this study was to investigate the mechanical properties of acrylic resins at different aging times for denture bases manufactured using the conventional method, microwave processing, milling, and 3D printing. Materials and Methods: A total of 160 rectangular samples (64 × 10 × 3.3 ± 0.03 mm) were prepared, divided among the four main resin groups, and subdivided into four analysis times (T0, T1, T2, and T3), resulting in 10 samples per subgroup. The samples were stored in distilled water at 37° ± 2°C for 24 hours (T0), then subjected to thermocycling at temperatures of 5° ± 1°C and 55° ± 1°C in different numbers of cycles: 5,000 (T1); 10,000 (T2); and 20,000 (T3). The mechanical properties evaluated were surface microhardness, flexural strength, and modulus of elasticity. Statistical differences between resin groups and aging time were evaluated using two-way analysis of variance (P < .05). Results: The 3D-printed resin showed the significantly lowest values of microhardness, flexural strength, and modulus of elasticity compared to other resins (P < .001). Conclusions: The CAD/CAM--milled denture resin showed mechanical properties similar to those of traditional resins (conventional and microwave-processed). The 3D-printing resin did not show adequate mechanical properties for long-term clinical use. Despite this, new studies are developing better properties of this resin for long-term use. [ABSTRACT FROM AUTHOR]

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Concrete stands as a fundamental material in the construction industry. However, it encounters challenges such as cracking, crumbling, or disintegration at elevated temperatures, attributed to high thermal stresses and low tensile strength. This study addresses these issues by reinforcing concrete samples with steel and polypropylene fibres, exposing them to temperatures ranging from 25 to 800°C, and conducting mechanical tests. In order to provide a comprehensive examination, a concrete mixture containing lightweight aggregate was also prepared and tested along with other mixtures. The test results showed that adding steel and polypropylene fibres enhanced or maintained compressive strength up to 200°C compared to the control sample. Furthermore, samples containing steel fibres exhibited the highest tensile strength across all temperatures. Notably, at 600°C and above, the lightweight concrete sample demonstrated comparable or superior compressive strength as well as tensile strength compared to the control sample. In addition, it was observed that polypropylene fibres began to melt at 400°C, leading to a decline in compressive and tensile strength in samples containing this fibre type at temperatures exceeding 400°C. [ABSTRACT FROM AUTHOR]

The study investigated the wood mechanical properties of black alder [Alnus glutinosa (L.) Gaertn.], a widely distributed deciduous tree in Europe valued for its suitability in silviculture and wood industry applications. The aim was to compare these properties among selected half-sib families and assess the relationship between wood hardness and other characteristics. Experimental plantations of black alder progenies from Lithuanian populations were established in different forest regions in 1998. The study analyzed various parameters for different genetic families, including tree diameter, height, wood hardness, moisture content, wood density, and mechanical properties. The findings revealed significant variability in wood properties among half-sib families, highlighting a strong genetic influence. Although the static modulus of elasticity showed no notable difference across families, other properties showed significant variations. Furthermore, the analysis identified weak correlations between wood hardness and other mechanical properties like density, modulus of elasticity, and bending strength. This suggests that wood hardness may not reliably indicate wood quality for industrial applications. Consequently, the study recommends considering alternative non-destructive properties, such as the dynamic modulus of elasticity, in future genetic studies of black alder for more accurate assessments of wood quality. [ABSTRACT FROM AUTHOR]

Pernambuco is the archetypal wood in modern bows of the violin-family. This species (Paubrasilia echinata) is endangered. Existing literature suggests remaining questions on how its properties' variability relates to qualification in bow-making, and to diversity. Here 61 pernambuco specimens, with various qualitative evaluations by makers, are characterised for physical, elastic, dynamic, and optical properties. Results are compared with standard relations between-properties, and with 53 pre-selected tropical hardwoods. The tested pernambuco stands in the medium-upper range of these pre-selected species for density (ρ) and modulus of elasticity (E). It is exceptional for its very low damping coefficient (tanδ) and very intense colour (red a*, yellow b* and chroma C*). Within-species variability is high. Qualification is mostly associated to ρ, colour hue angle h° and gloss, then to elasticity – but E and E/ρ (specific modulus) overlap between groups. Qualification involves appearance (L*, h°, gloss) when freshly cut, and with anticipation of changes after ageing or finishing. The properties (damping, chroma) that make pernambuco exceptional among species, are not clearly related to the qualification within the studied sampling. Analyses help better understand the specificities of pernambuco, and highlight the multifactorial nature of wood selection at two levels: between-species preference, and within-species qualification. [ABSTRACT FROM AUTHOR]

This article investigates the durability of recycled self-compacting concrete in relation to its resistance against freeze-thaw cycles and alkali-silica reactions. It explores the properties of fresh concrete, investigates the impact of various additives, and evaluates key factors such as spalling, weight loss, compressive strength, expansion rate, and ultrasonic properties in hardened concrete samples incorporating different levels of recycled aggregates. The findings illustrate the feasibility of achieving self-compacting recycled concrete by increasing the use of superplasticizers and adding 10% beach sand. Furthermore, incorporating 10% micro-silica and 7.5% wollastonite in the recycled mix enhances the strength of all samples, with the 25% recycled material sample demonstrating the highest strength and durability. Despite a decrease in strength and increased expansion as recycling percentages and freeze-thaw cycles rise, the recycled samples maintain acceptable durability. Additionally, this study employs the R programming language to elucidate the relationship between compressive strength and modulus of elasticity, offering valuable insights into recycled concrete performance and behavior. [ABSTRACT FROM AUTHOR]

BACKGROUND: Complex phosphates (CP) can improve the physicochemical properties and gelation properties of myofibrillar fibrous protein (MP) in mixed meat products, but an excessive intake of phosphates over a long period of time is harmful to health. The present study investigated the effects of partial or complete substitution of CP with sodium bicarbonate (SB) on the physicochemical properties and gel properties of beef‐pork‐chicken mixed myofibrillar protein (BPC‐MP), aiming to evaluate the feasibility of this method in reducing the amount of phosphate in mixed meat products. RESULTS: Under the optimal substitution conditions, the turbidity of BPC‐MP was reduced by 37.8%, the net negative potential was increased by 28.9% and the modulus of elasticity (G') was increased. The tertiary structure indexes of protein (including fluorescence intensity, surface hydrophobicity and active thiol content) were significantly changed, whereas the α‐helix and β‐turn angle contents in the secondary structure of protein were significantly increased. In addition, the water retention ability and strength of gel were also improved, which were increased by 20.7% and 42.6%, respectively. The results of scanning electron microscopy showed that the SB substitution group had a more compact and ordered microstructure. CONCLUSION: The results showed that partial substitution of CP with SB reduced the amount of phosphate added to BPC‐MP and had a positive effect on the physicochemical and gel properties of BPC‐MP. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) is a potential material for application as nano-reinforcements in cementitious composites owing to its high-water dispersibility, aspect ratio and outstanding mechanical characteristics. In this study, the combined effect of GO and fly ash on strength properties, stress–strain behaviour and static modulus of elasticity of high-strength concrete was investigated. In addition, microstructure has been characterized using SEM and EDS techniques. The addition of GO at 0.15% and the replacement of cement with fly ash at 10, 20 and 30% by weight was considered. The results exhibited that the addition of GO at 0.15% improved the compressive and flexural strength of concrete by 24.3 and 25.2%, respectively, at 7 days. The combined effect of GO and fly ash on the strength properties of concrete at 7 days was greater than control concrete demonstrating that GO can offset the effect of fly ash on delaying the strength growth at an early age. From the experimental results, it can be concluded that the addition of GO and fly ash into the concrete improved both the strength and elastic modulus, consequently exhibiting positive synergy in hybridizing GO and fly ash into the concrete. Also, the microstructure properties indicated that the GO and fly ash-based concrete mixes exhibited a denser microstructure. Furthermore, a nonlinear numerical model was also created for GO and fly ash-based concrete with finite element-based software ATENA-GiD to validate the experimental findings. The nonlinear numerical model successfully predicted the behaviour under monotonic axial compression and was quite beneficial in minimizing the tedious experimental testing. Finally, it is found that the findings of both the experimental and numerical investigations are in good agreement. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effects of manure and vermicompost in terms of soil elasticity modulus changes in loam soil. The uniaxial compression test measures the compressive strength of a soil cylinder without any lateral load. The modulus of elasticity was determined by plotting the strain-stress diagrams and calculating the slope of these diagrams. The increase in moisture and organic matter content significantly improved soil flexibility and decreased its elasticity modulus. It was found that adding animal manure had a greater effect on the flexibility of the soil as compared to vermicompost, while the elasticity modulus of the samples containing animal manure was lower. The interaction effect of moisture and the organic matter content indicated that the increase in humidity was more effective in the soil containing vermicompost as compared to the soil containing manure, such that when the manure rate was around 19%, the moisture increase had no significant impact on the elasticity modulus. It was found that adding organic matter was more effective at the low moisture level of 15.5% than at higher moistures where the effect of adding organic matter did not affect the soil elasticity modulus decrement as strongly. [ABSTRACT FROM AUTHOR]

In this study, onium‐ion‐added nanoclay (NC)/microcellular polypropylene (PP) composites were created using a conventional injection molding machine. A chemical foaming agent was utilized to facilitate mixing. The primary focus was to analyze how altering the NC content affects the mechanical characteristics and the properties of the endothermic chemical foaming agent added PP/NC composites. The composites were created using a chemical foaming agent at a weight ratio of 1 wt% and NC at weight ratios of 0 wt%, 2.5 wt% and 5 wt%. The findings indicated that an increase in the NC ratio led to higher cell count and cell density, along with a reduction in cell diameter. Additionally, the outcomes demonstrated that the foaming of PP/NC composites resulted in decreased modulus of elasticity and tensile strength while enhancing impact strength. © 2024 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Titanium alloy has been widely used in several industrial applications because it has superior mechanical properties and good corrosion resistance. Titanium alloys are also widely used as an implant material, and the Ti-6Al-4 V is one of the most popular. Recent research proves that the release of Al and V ions from the Ti-6Al-4 V alloy can cause long-term health problems. Therefore, Titanium alloys without Aluminum and Vanadium were developed as implant material. In this paper we develop Ti-30Nb-xSn with x = 0, 2, 5 dan 8% (%wt.) as implant material. The alloying melted in an electric arc vacuum furnace, homogenised at 1000°C holding time 5 h with ice water quench. The specimen was characterised by a Vickers hardness tester, optical metallography, SEM-EDS, XRD, ultrasonic test to investigate the modulus of elasticity and corrosion testing with the potentiodynamic polarisation method. The optimum results are reached at Ti-30Nb-5Sn alloys where the β-phase optimum with modulus elasticity valued 112 GPa, and hardness Vickers valued 312.2 HV. In addition, the addition of Sn can increase corrosion resistance optimum with valued 90.11 × 10−6mmpy. [ABSTRACT FROM AUTHOR]

With the aid of 3D printing, this study attempts to calculate the effective elastic modulus as well as the dimensional correctness and porosity of bolt samples. The main contribution of this study is the identification of the bolt sample porosity that is most appropriate for use as cancellous bone implants. It was discovered by contrasting the printed bolt sample's size, porosity, and effective modulus of elasticity with cancellous bone, as well as with the CAD model. This study examines the characteristics of bolt PLA samples created using SolidWorks software and manufactured in three dimensions using FDM. Observing the uniaxial tensile and determining its elasticity using stress-strain curves were the goals. Three of the five bolt samples used in the tests yielded essentially accurate results. Our research will aid in comprehending numerous facets of creating, testing, and optimising 3-D printed PLA bolts for use in real-world applications. The effective modulus of elasticity is generated by computer simulation using the MSC Marc software. Bolts with porosity variations of 42.9 percent and 58.1 percent revealed that the results of the printed bolt were flawless, but those with porosity variations of 22.3 percent and 73.4 percent generated incorrect impressions because they had too few pores or features. However, bolts with porosities of 58.1 and 73.4 percent exhibited a suitable elastic modulus that matched the span of cancellous bone. The bolt with a porosity of 58.1 percent was found to be the most suitable for usage as a cancellous bone implant with precise fabrication results. [ABSTRACT FROM AUTHOR]

Translation abstract Process‐accompanying derivation of mechanical properties of high‐strength concretes during rapid productionThe prefabrication of reinforced concrete components bears considerable advantages over conventional in‐situ concrete construction. For instance, an integration of rapid heat treatment allows the processing time in rapid production to be reduced to just a few hours. Treatment time and temperature affect the development of the mechanical properties most. Control of the latter ensures the quality of the components. For concrete components, destructive tests on accompanying samples are common. In this paper, a method is developed with which compressive strength, modulus of elasticity and bond strength can be derived from testing integrated in the production process. The suitability of rebound hammer testing is analysed, taking into account the boundary conditions of heat treatment. Experiments are used to determine the specified target values for the high‐strength Nanodur concrete during production with varying times of heat treatment. The experimental results are compared to the ones derived from standardised correlations. In this way, a model is formed with which primarily the compressive strength and along with it the modulus of elasticity and the bond strength are obtained. The method is discussed against the experimental and theoretical findings. Its application is demonstrated on a simple example and recommendations for checking the mechanical properties in rapid production practically are provided. [ABSTRACT FROM AUTHOR]

Postoperative adhesion (POA) has emerged as a prevalent clinical challenge in soft tissue repair, emphasizing the critical need for preventive measures. However, the complex POA development process makes POA prevention from a single aspect insufficient. Hence, a curcumin‐loaded poly‐L‐lactic acid‐poly (caprolactone) micro‐nano conjugated fibrous membrane (PAPC MCFM (cur)) is engineered to synergistically prevent POA from multiple perspectives, in which poly (caprolactone) (PCL) nanofibers (118 ± 12 nm) with low orientation traverse the oriented poly‐L‐lactic acid (PLLA) microfibers (2.0 ± 0.3 µm). The PAPC MCFM not only significantly improves the mechanical properties of the anisotropic fibrous membrane (AIFM) that the modulus of elasticity and the tensile strength in the direction vertical to microfiber orientation increase by 4.5 and 13.0 times, respectively, but also can further enhance the “contact guidance effect” of AIFM, i.e., hindering fibroblast adhesion, proliferation, and differentiation to myofibroblast through inhibiting integrin β1 activation, vinculin expression and focal adhesion (FA) formation, and the nuclear localization activation of yes‐associated protein (YAP). Except for these effects, PAPC MCFM loading with 2.5 mg mL−1 curcumin can further prevent POA by delivering anti‐inflammatory, antioxidant, and antibacterial properties, and by suppressing fibrosis through decreased transforming growth factor‐β1(TGF‐β1) expression, showing effective POA prevention in rat abdominal cavity and rabbit dura mater models. [ABSTRACT FROM AUTHOR]

In order to contribute to the demanded sustainability transparent poly(methyl methacrylate) (PMMA) composites with cellulose nanocrystals (CNC) up to high shares of 50 wt% were prepared by in situ radical polymerization in green solvent Cyrene. The weight average molecular weights of PMMA were in the range from 144,000 to 160,000 g mol−1 and the dispersity was in the range of 1.49 to 1.89 with high conversion of monomer to polymer. The DSC thermal analysis showed that the glass transition temperature of pure PMMA was at 99°C while in composites increased from 103°C up to 129°C with the increase of CNC from 1 wt% to 50 wt%. TGA shows that the addition of CNC does not have a significant effect on the thermal stability of PMMA. In composites Young's modulus increases with the increasing CNC ratio and composites with 50 wt% of CNC showed more than twice the modulus of the PMMA matrix. The SEM images indicate uniform distribution of CNC in polymer matrix. The transparent and semitransparent PMMA/cellulose composites of improved sustainability with higher modulus of elasticity and glass transition temperature can be used as lightweight materials for a wide range of technical and everyday applications as well as optical lenses or acoustic lenses for ultrasound transducers and other devices. Highlights: Cellulose nanocrystals/PMMA composites fabricated by a green in situ process.Synthesized PMMA matrices have high molecular weights.Improved elastic modulus and glass transition temperature were achieved.Prioritizing eco‐friendly chemicals for a greener production approach. [ABSTRACT FROM AUTHOR]

Glass fiber‐reinforced polymer (GFRP), extensively employed in diverse industries, generates considerable waste, especially from decommissioned wind turbine blades. Our research group has developed a new method of mechanical recovery for GFRP from wind turbine blades. In this study, waste GFRP was processed into a mixed particle size of 0.9–6 mm using a crusher and a screening machine, and then added as reinforcement materials to particleboards. The effects of different levels of four factors (GFRP addition, hot pressing temperature, hot pressing time, and binder dosage) on the properties of GFRP particleboards were evaluated by orthogonal experiments. The study results showed that the particleboards with 30 wt% GFRP improved modulus of rupture (MOR), modulus of elasticity (MOE), and internal bonding strength (IB) by 74.94%, 42.28%, and 92.05%, respectively, compared to pure poplar particleboards. Moreover, GFRP particleboards demonstrated better water resistance and dimensional stability than commercial particleboards and excelled in thermal stability. Recycling GFRP waste from decommissioned wind turbine blades and incorporating it into particleboard production can reduce environmental pollution, increase the resource recovery utilization rate, and contribute to sustainable manufacturing practices. Highlights: Low‐cost and efficient methods of recycling wind turbine blades were proposed.Recycled GFRP from wind turbine blades can be used as reinforcement for particleboard.The prepared particleboards have excellent physical and mechanical properties and are thermally stable.Determination of the optimal glass fiber‐reinforced polymer addition level in particleboard at 30 wt%. [ABSTRACT FROM AUTHOR]

Highlights Fiber‐reinforced composites are widely used in civil engineering, aerospace, automotive, and medical sectors. However, these composites undergo aging due to factors such as temperature, humidity, load, and so on, during their usage. As a result, their performance deteriorates, and predicting their durability under real service conditions is a significant challenge. In order to better understand the durability of fiber‐reinforced composites, this article summarizes their microscopic aging mechanism under natural aging conditions and analyzes the changing rules of tensile, bending, and shear properties of composites under seven typical climate types, including tropical desert climate, temperate continental climate, temperate oceanic climate, Mediterranean climate, seasonal climate, tropical rainforest climate, and seawater immersion. This article reviews various durability prediction models, such as the Arrhenius model, prediction models based on residual modulus of elasticity and residual strength, and median strength regression analysis. To enhance the accuracy of aging life prediction during the natural aging process of composites, it is important to consider the influence of loads under real service conditions, incorporate different climatic types, utilize comprehensive mechanical property indices, establish an equivalent conversion relationship between natural aging and accelerated aging, and create a database with unified test standards. The aging mechanisms of FRP after exposure in natural aging environments are discussed. The tensile, bending, and shear properties of FRP after exposure under seven climate types are discussed. The predictive models are proposed for the FRP used in natural aging. The future research needs are proposed for the FRP used in natural aging. [ABSTRACT FROM AUTHOR]

The incorporation of carbon nanotubes (CNTs) in concrete can improve the physical, mechanical, and durability properties. However, the interaction of CNTs with concrete and their effect on the mechanical properties remains a challenging issue. Also, the determination of mechanical properties through experimental testing is time‐consuming, laborious, and uneconomical. This study focuses on the development of machine learning (ML) models for the prediction of the mechanical properties of concrete. A comprehensive data set of 758 CNT‐modified concrete specimens was established for the compressive strength (CS), split tensile strength (STS), flexural strength (FS), and modulus of elasticity (MOE) values from the experimental studies in the literature. Afterward, the predictive models were developed using multilinear regression (MLR), support vector machine (SVM), ensemble methods (EN), regression tree (RT), and Gaussian process regression (GPR). It was found that among ML models, the GPR model predicted the CS, STS, and FS at the highest efficiency with the coefficient of determination (R2) of 0.83, 0.78, and 0.93, respectively while the performance of the SVM model was superior for predicting MOE with an R2 value of 0.91. The mean absolute error (MAE) of the GPR model for CS, STS, FS, and MOE were 2.92, 0.26, 0.35, and 1.31, respectively which were also lesser than other models. The training time of different models demonstrated that the GPR model has also a lower training time (~3 s) as compared to other models which indicates it has a high accuracy‐to‐time cost ratio. Further, the most influential parameters on CS were age, cement, water–cement ratio, and carbon nanotubes. The one‐way partial dependence analysis showed a direct correlation for age and cement but an inverse correlation for the water–cement ratio and fine aggregate. The graphical user interface provides the implication of the developed models for practical applications. [ABSTRACT FROM AUTHOR]

This study investigates the potential of utilizing hazelnut shells (HS) as an innovative filler in three-layer plywood technology, addressing the growing need for sustainable, high-performance materials. Traditional plywood production relies on adhesives enhanced with various fillers to improve physical, mechanical, and operational characteristics. This research explores using native, chemically modified, and activated carbon derived from hazelnut shells as fillers in urea–formaldehyde (UF) resin. The produced plywood's mechanical properties, water absorption, and formaldehyde emissions were thoroughly analyzed. Key findings demonstrate that incorporating 10 part by weight (pbw) native hazelnut shell flour significantly enhances the modulus of rupture (MOR) to 138.6 N mm−2 and modulus of elasticity (MOE) to 13,311 N mm−2. Chemically modified hazelnut shell flour achieves optimal results at 5 pbw, while activated carbon from hazelnut shells, even at 1 pbw, markedly improves bonding strength (2.79 N mm−2 referred to 0.81 N mm−2 for reference sample without filler added). Notably, activated carbon effectively reduces formaldehyde emissions (2.72 mg 100 g−1 oven dry panel referred to 3.32 mg 100 g−1 oven dry panel for reference samples with 10 pbw filler) and improves water resistance, indicating better further dimensional stability and lower environmental impact. The study also shows that excessive filler content negatively affects strength parameters, confirming the importance of optimizing filler concentration. These results highlight the potential of hazelnut shells as an eco-friendly alternative filler in plywood production, contributing to waste valorization and environmental sustainability. This study supports the practical application of hazelnut shell fillers, promoting a circular economy and reducing reliance on traditional, less sustainable materials, thus providing a valuable solution for the wood composite industry. [ABSTRACT FROM AUTHOR]

In this study, Poly(vinyl alcohol)/cellulose nanofiber (PVA/CNF) hydrogels have been successfully prepared using γ-ray irradiation, annealing, and rehydration processes. In addition, the effects of CNF content and annealing methods on the hydrogel properties, including gel fraction, micromorphology, crystallinity, swelling behavior, and tensile and friction properties, are investigated. Consequently, the results show that at an absorbed dose of 30 kGy, the increase in CNF content increases the gel fraction, tensile strength, and elongation at break of irradiated PVA/CNF hydrogels, but decreases the water absorption. In addition, the cross-linking density of the PVA/CNF hydrogels is significantly increased at an annealing temperature of 80 °C, which leads to the transition of the cross-sectional micromorphology from porous networks to smooth planes. For the PVA/CNF hydrogel with a CNF content of 0.6%, the crystallinity increases from 19.9% to 25.8% after tensile annealing of 30% compared to the original composite hydrogel. The tensile strength is substantially increased from 65.5 kPa to 21.2 MPa, and the modulus of elasticity reaches 4.2 MPa. Furthermore, it shows an extremely low coefficient of friction (0.075), which suggests that it has the potential to be applied as a material for artificial joint cartilage. [ABSTRACT FROM AUTHOR]

Studies on self-binding hot-pressed fiberboards using agricultural byproducts aim to identify alternatives to scarce wood resources. Particle size and mixture significantly impact strength, although direct comparisons are difficult due to differences in study methods. We evaluated fiberboards made from the two perennial biomass crops Miscanthus and Paulownia and compared them to Picea (spruce), using five distinct particle size blends prepared from milled and sieved particles, respectively. The boards were evaluated for their modulus of elasticity, modulus of rupture, reaction to fire, water absorption, and thickness swelling. All specimens exhibited normal ignitability, as defined by Euroclass E according to EN13501-1. The results indicate that mechanical performance improves with increasing density, which correlates with higher proportions of finer particles. Notably, the finer Miscanthus blends and all Paulownia samples met the modulus of elasticity requirements of EN 622. [ABSTRACT FROM AUTHOR]

Early-age masonry structures require temporary support until they achieve full strength. Nevertheless, there is a limited understanding of the properties of freshly laid masonry and the design of newly constructed, unsupported masonry walls. This situation has led to numerous instances of structural damage and injuries to workers, prompting conservative construction bracing techniques. This paper presents comprehensive experimental studies on early-age mortar cubes and masonry prisms to assess the effects of curing time on the compressive properties of masonry assemblies, which is necessary for the design of temporary bracing. The change in modulus of elasticity and compressive strength of masonry prisms and mortar with curing time has been experimentally assessed. The results indicate that the compressive strength of freshly cast mortar cubes is relatively insignificant until approximately 24 h after construction, when it was observed to increase logarithmically. Regarding the performance perspective, the compressive strength of early-age masonry prisms is inconsiderable, less than 15% of full strength during the first day after construction. By contrast, regarding the life safety perspective, the compressive properties of a mortar joint within a masonry assembly (which is of more practical interest) appear to have no effect on the failure strength of concrete masonry prisms over the range of ages tested. The failure modes of the early-age mortar cubes and early-age masonry prism samples depend on the curing time, and different failure modes occurred before and after the start of the primary hydration phase, which is 20.8 h after construction. It is anticipated that the proposed research will provide valuable material properties leading to efficient design of control devices (e.g., temporary bracing) and improved guidelines for concrete-block masonry construction. [ABSTRACT FROM AUTHOR]

The dissolution of calcium ions in concrete in a low-alkalinity environment is an important factor causing a significant increase in the porosity of internal concrete, leading to a deterioration in its mechanical properties and affecting the durability of the concrete structure. In order to improve the reliability of concrete durability design and significantly increase the service life of concrete structures located in soft water environments, it is crucial to establish an analytical method to predict the elastic modulus (Edc) of cement slurry systems suffering from calcium dissolution. Firstly, the hydrated cement particles are regarded as a three-phase composite sphere composed of unhydrated cement particles (UC), a high-density hydrated layer (H-HL), and a low-density hydrated layer (L-HL). By introducing the equivalent inclusion phase (EQ) composed of UC and H-HL, the three-phase composite sphere model can be simplified into an equivalent hydrated cement particle model composed of EQ and L-HL. Finally, the Edc of the two-phase composite sphere composed of the equivalent hydrated cement particles and the porosity of the dissolved cement slurry system are solved by using elasticity theory. The effectiveness of the developed analytical method is verified by comparing it with third-party numerical results. Based on this method, the effects of hydration degree, volume ratio of calcium hydroxide (CH) to hydrated calcium silicate (C-S-H), and volume ratio of inner C-S-H to outer C-S-H on the Edc of the dissolved cement slurry system are analyzed. The parameter analysis indicates that among the three influencing parameters, the hydration degree has the greatest effect on the Edc of the dissolved cement slurry system. This study provides an analytical method for predicting Edc, which can provide some references for the durability design of concrete after calcium dissolution. [ABSTRACT FROM AUTHOR]

The interfacial dilational rheology of silica nanoparticles (NPs) directly reflects the relationship between surface structure and interfacial behaviors in NPs, which has attracted significant attention in various industrial fields. In this work, modified silica nanoparticles (MNPs) with various alkyl chain lengths were synthesized and systematically characterized using Fourier transform infrared spectra, Zeta potential, and water contact angle measurements. It was found that the MNPs were successfully fabricated with similar degrees of modification. Subsequently, the interfacial behaviors of the MNPs in an n-octane/water system were investigated through interfacial dilational rheological experiments. The length of the modified alkyl chain dominated the hydrophilic–lipophile balance and the interfacial activity of the MNPs, evaluated by the equilibrium interfacial tension (IFT) variation and dilational elasticity modulus. In the large amplitude compression experiment, the balance between the electrostatic repulsion and interfacial activity in the MNPs was responsible for their ordered interfacial arrangement. The MNPs with the hexyl alkyl chain (M6C) presented the optimal amphipathy and could partly overcome the repulsion, causing a dramatic change in surface pressure. This was further confirmed by the variations in IFT and dilational elasticity during the compression path. The study provides novel insights into the interfacial rheology and interactions of functionally modified NPs. [ABSTRACT FROM AUTHOR]

The increasing numbers of total joint replacements and related implant-associated infections demand solutions, which can provide a high-dose local delivery of antibiotics. Antibiotic-loaded bone cement (ALBC) is an accepted treatment method for infected joint arthroplasties. The mechanical properties of low-dose gentamicin-loaded bone cement (BC) in medium- and high-viscosity versions were compared to unloaded BC using a vacuum mixing system. As an additional control group, manual mixed unloaded BC was used. In a uniaxial compression test, ultimate compressive strength, compressive yield strength, and compression modulus of elasticity, as well as ultimate and yield strain, were determined according to ISO 5833-2022 guidelines. All groups exceeded the minimum compressive strength (70 MPa) specified in the ISO 5833 guidelines. Both ALBC groups showed a similar ultimate compressive and yield strength to the unloaded BC. The results showed that vacuum mixing increased the compression strength of BC. ALBC showed similar compressive strength to their non-antibiotic counterparts when vacuum mixing was performed. Added low-dose gentamicin acted as a plasticizer on bone cement. From a biomechanical point of view, the usage of gentamicin-based ALBC formulations is viable. [ABSTRACT FROM AUTHOR]

Phthalonitrile thermosets are known for their excellent mechanical, physico-chemical, and fire-retardant properties, making them attractive for aerospace and mechanical engineering applications. When producing and applying phthalonitrile-based structural parts, it is essential to consider aspects such as processability and the long-term stability of the material's properties at high temperatures. In our previous studies, we demonstrated that resins containing phosphate-bridged bisphthalonitrile monomers are easily processable due to their low melting temperature and wide processing window. In this study, we investigated the impact of bis(3-(3,4-dicyanophenoxy)phenyl)phenyl phosphate (PPhPN) monomer content on physico-chemical and mechanical properties, thermal stability, and thermal oxidative stability. This research highlights the importance of conducting long-term thermal oxidative aging studies in addition to thermogravimetric analysis to properly assess the stability of thermosets. The findings indicate that adding less than 15% of PPhPN results in the formation of a crystalline phase, which impairs the resin's processability. Conversely, a high PPhPN content reduces the material's thermal oxidative stability. Therefore, based on mechanical and physico-chemical tests after thermal oxidative aging, it can be concluded that a 10–15% concentration of the phosphate-containing monomer enables easy processability of the phthalonitrile resin and provides excellent long-term thermal oxidative stability at temperatures up to 300 °C, while maintaining a flexural strength exceeding 120 MPa and an elasticity modulus of 4.3 GPa. [ABSTRACT FROM AUTHOR]

The industrial production of cement contributes significantly to greenhouse gas emissions, making it crucial to address and reduce these emissions by using fly ash (FA) as a potential replacement. Besides, Graphene oxide (GO) was utilized as nanoparticle in concrete to augment its mechanical characteristics, deformation resistance, and drying shrinkage behaviours. However, the researchers used Response Surface Methodology (RSM) to evaluate the compressive strength (CS), tensile strength (TS), flexural strength (FS), modulus of elasticity (ME), and drying shrinkage (DS) of concrete that was mixed with 5–15% FA at a 5% increment, along with 0.05%, 0.065%, and 0.08% of GO as potential nanomaterials. The concrete samples were prepared by using mix proportions of design targeted CS of about 45 MPa at 28 days. From investigational outcomes, the concrete with 10% FA and 0.05% GO exhibited the greatest CS, TS, FS, and ME values of 62 MPa, 4.96 MPa, 6.82 MPa, and 39.37 GPa, on 28 days correspondingly. Besides, a reduction in the DS of concrete was found as the amounts of FA and GO increased. Moreover, the development and validation of response prediction models were conducted utilizing analysis of variance (ANOVA) at a significance level of 95%. The coefficient of determination (R2) values for the models varied from 94 to 99.90%. Research study indicated that including 10% fly ash (FA) as a substitute for cement, when combined with 0.05% GO, in concrete yields the best results. Therefore, this approach is an excellent option for the building sector. [ABSTRACT FROM AUTHOR]

This document discusses the development, characterization, application, and recycling of novel construction materials. It highlights the need for sustainable alternatives in the construction industry to reduce CO2 emissions and address environmental concerns. The document explores various innovative approaches, such as incorporating waste materials, additives, and recycled aggregates, to enhance the mechanical properties, sustainability, and durability of construction materials. Examples include using waste rubber to reduce stiffness, incorporating solid-solid phase change materials for heat storage, and utilizing vegetal fabrics and recycled aggregates. These advancements aim to create more resilient and environmentally friendly construction materials. [Extracted from the article]

Under the same geological conditions, the thickness and length of the reinforced strip, the slope ratio of the reinforced embankment, the modulus of elasticity of the fill and the reinforced strip, and the friction angle at the interface between the reinforcement and the soil, are the main design parameters that have an important influence on the stress, deformation, and stability of the encompassing reinforced soil embankment. To quickly and accurately determine the optimal design parameters for reinforced soil embankments with wrapped faces, ensuring minimal cost, while maintaining structural safety, we propose a design parameter prediction model based on a GA–BP neural network. This model evaluates parameters within their specified ranges, using maximum lateral displacement, maximum vertical displacement, maximum stress in the XZ direction, the maximum shear strain increment, and the safety factor, as assessment criteria. The primary objective is to minimize the overall cost of the embankment. A comparison with five machine learning algorithms shows that the model has high prediction accuracy, and the optimal design parameter combinations obtained from the optimization search can significantly reduce the cost of the embankment, while controlling the displacement and stability of the embankment. Therefore, the GA–BP network is suitable for predicting the optimal design parameters of reinforced soil embankments with wrapped faces. [ABSTRACT FROM AUTHOR]

Highlights Wood flour (WF) at 10 wt.% and 20 wt.% loadings was used as a reinforcing filler to enhance the applicability of polypropylene (PP) for 3D printing. After performing printability tests of PP wood plastic composites (WPCs), the mechanical properties of both injection‐molded and 3D‐printed PP WPC specimens were explored. Test specimens were prepared from 3D printed hexagons for analyzing the mechanical properties. Adding WF to neat PP increased the storage modulus and the glass transition temperature while decreasing the degree of crystallinity and the coefficient of thermal expansion, while enhancing the printability of neat PP. The tensile strength, tensile modulus of elasticity, flexural strength, and flexural modulus of elasticity of injection‐molded neat PP improved by up to 21%, 59%, 30%, and 56%, respectively, with 20 wt.% WF. However, the impact strength of injection‐molded neat PP decreased by 85%, with 20 wt.% WF. After 3D printing, the tensile strength and tensile modulus of elasticity of printed neat PP increased by up to 84% and 60%, respectively, with 20 wt.% WF. The flexural strength and flexural modulus of elasticity of neat printed PP remained unchanged compared to those of PP filled with 20 wt.% WF, while the impact strength decreased by 87%. WF was used as a reinforcement in polypropylene designed for 3D printing A pilot‐scale, pellet‐fed 3D printer was used to print hollow hexagons, and then test specimens were fabricated from these hexagons for mechanical properties The tensile and flexural properties of 3D printed neat polypropylene improved, while the impact strength decreased after adding 20 wt.% WF to the neat PP. [ABSTRACT FROM AUTHOR]

The effect of hydrostatic pressure on the relative stabilities of the four main structures in CuZr has been estimated using first‐principles calculations. The results indicate that hydrostatic pressure induces the B19′ → B19 transformation at ~40 GPa and Cm → B19 transformation at ~68 GPa. At 0 GPa, these CuZr structures exhibit analogous values of B, G, and E and small difference in σ. However, the differences between these structures become appreciable in B, G, E, and σ values. 3D graphs of Young's modulus reflect the elasticity is directional. Pressure promotes the increase of elastic anisotropy degree of B2. For B19′ and Cm, the variation trends under pressure firstly decrease, then slightly increase, while that is opposite for B19. The quasi‐harmonic Debye model is used to evaluate the effects of temperature and pressure on the thermodynamic properties (heat capacity, thermal expansion coefficient, Debye temperature, and Grüneisen parameter) of the CuZr structures. [ABSTRACT FROM AUTHOR]

Characterizing the evolution of mechanical properties of hot dry rock (HDR) after supercritical CO2 (CO2(sc)) injection is crucial for assessing the heat extraction rate and reservoir security of CO2 based enhanced geothermal systems. This study designed the experiments of triaxial seepage and mechanical properties considering no CO2(sc) injection, CO2(sc) injection, and alternating injection of water-CO2(sc) (AIWC) in granite at 150–300 ℃. The experiments can reveal the mechanical properties of HDR in single-phase CO2 zone, CO2-water two-phase zone and dissolved CO2 liquid phase zone in HDR reservoir. The results indicate that the failure mode of the rock samples primarily exhibits sudden instability after no CO2(sc) injection and AIWC, whereas it predominantly manifests progressive instability after CO2(sc) injection. Compared with 25 ℃, the uniaxial compressive strength (UCS) after no CO2(sc) injection at 150–300 ℃ decreased by 13.86%–32.92%. After CO2(sc) injection, the UCS decreased by 40.79%–59.60%. After AIWC, the UCS decreased by 27.74–40.48%. This shows that the strength of rock mass in the single-phase CO2 zone is lower than that in the other two zones, and this weakening phenomenon increases with the increase of temperature difference. At the same temperature, the elasticity modulus after AIWC was greater than that after no CO2(sc) injection and CO2(sc) injection. With no CO2(sc) injection, when the temperature was increased to 200 ℃ and 300 ℃, intergranular cracks and transgranular appeared respectively. After AIWC, mineral crystals such as calcite were precipitated on the surfaces of the connected large cracks, accompanied by kaolinite clay minerals. This increases the frictional contact of the mineral particles and enhances the stability of the HDR reservoir. [ABSTRACT FROM AUTHOR]

Self‐healing polymers have been developed to improve durability and reduce costs associated with maintenance during service. The addition of thermoplastics to thermosets to produce mendable polymers appears as a promising self‐healing technique. In this study, poly (ethylene‐co‐methacrylic acid) (EMAA) was added to epoxy resin and the effects of EMAA addition on epoxy properties were evaluated. Specimens with two different contents of thermoplastic and particles sizes were manufactured. A two‐level full factorial experimental design was used to evaluate the effect of particle size and particle content on properties of epoxy modified with addition of EMAA. Tensile tests and dynamic mechanical analysis (DMA) were used and the evaluated responses were tensile strength, modulus of elasticity, and glass transition temperature (Tg). X‐ray computed tomography (XCT) was used to investigate particle size and concentration after manufacturing. It was found that the particle concentration has greater effects on stress–strain behavior of epoxy while Tg was not significantly affected by neither of the analyzed entrance variables. [ABSTRACT FROM AUTHOR]

Background: Carbon fiber composites were chosen because of their advantages in terms of high strength, light weight, and resistance to high temperatures. The sound dampening on go-karts functions to reduce disturbances produced by the engine, and the use of carbon fiber composite material is expected to improve acoustic performance and reduce the overall weight of the vehicle. Purpose: This research aims to analyze the mechanical strength characteristics of carbon fiber composites used as dampening materials in go-karts. Methode: The research method involves making test specimens from carbon fiber composites with an epoxy resin matrix. Variations in fiber presentation and layer orientation were tested to determine the optimal configuration. Tests carried out include bending tests, impact tests and Vickers hardness tests to measure the modulus of elasticity and resistance to dynamic loads. Result: The test results showed that the ratio of carbon to resin 85/15 resulted in the highest bending strength (0.712 N/mm²), while the ratio of 90/10 yielded the lowest strength (0.529 N/mm²). Specimen C with a ratio of 80/20 has a moderate strength (0.662 N/mm²) and the highest impact value (0.751 joule/mm²). The lowest impact value was obtained in specimen A with a ratio of 90/10 (0.445 joule/mm²). For the Vickers hardness test, specimen B with a ratio of 85/15 had the highest hardness (84.09 HVN), while specimen A with a ratio of 90/10 showed the lowest hardness (10.4 HVN). Specimen C with a ratio of 80/20 has a moderate hardness (46.65 HVN). Conclusion: Based on the results of the study, carbon fiber composites with a ratio of carbon to resin 85/15 show optimal mechanical strength characteristics for use as a silencer material in go-karts. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach to enhance epoxy resin formulations by using SILP materials as multifunctional hardeners and fillers in composite structures reinforced with carbon and flax fibers. This study explores the integration of ionic liquids (ILs) onto a silica support structure, presenting various permutations involving silica selection, ionic liquid choice, and concentration. The focus of this study was to elucidate the influence of SILP on resin curing ability and the mechanical properties of the resulting composites. Detailed research was conducted, including Brunauer‐Emmett‐Teller analysis (BET) for SILP materials and curing characterization for epoxy resin formulations with different SILP materials. Furthermore, the mechanical properties of the obtained composites were determined by Scanning Electron Microscopy analysis (SEM) (the force at break, the maximum elongation at break, tensile strength, and modulus of elasticity). Through SILP incorporation, the mechanical properties of composites, including the modulus of elasticity and tensile strength, are substantially improved, a phenomenon akin to traditional filler effects. The findings highlight SILP materials as prospective candidates for concurrent hardening and filling roles within composites (through a single‐step procedure, with prolonged storage stability and controlled processing conditions), particularly pertinent as the composite industry veers toward epoxy bioresins necessitating liquefaction via temperature application. [ABSTRACT FROM AUTHOR]

Recycled concrete aggregates (RCA) provide an environmentally friendly solution by reducing the depletion of natural resources. This study investigates the impact of the expansion history of RCA on its reactivity with alkalis in newly produced concrete. Parent concrete samples were collected from the RILEM AAR‐4 curing cabinet (60°C and >90% RH) to produce coarse RCA with four different expansion levels (0.00%, 0.05%, 0.12%, and 0.20%). The results show that the expansion levels of the new concrete mixtures decreased as the ASR expansion history of parent concrete increased. The 20‐week compressive strength and elastic modulus of the reactive aggregate concrete containing no mineral admixture and exposed to AAR‐4 test conditions were lower than those of their water‐cured counterparts. However, no decrease was observed in the elastic modulus of concrete mixtures that showed an expansion level lower than 0.03% (the maximum expansion for nonreactive aggregate as recommended by the RILEM AAR‐4 standard). [ABSTRACT FROM AUTHOR]

This study conducted dynamic triaxial tests on a typical poured asphalt concrete material of core walls in Xinjiang, exploring the dynamic characteristics of poured asphalt concrete under various confining pressures, principal stress ratios, and vibration frequencies. On this basis, the dynamic constitutive relationship of poured asphalt concrete was investigated using the Hardin–Drnevich model. The results indicate that under different confining pressures, principal stress ratios, and vibration frequencies, the variation patterns of the backbone lines of dynamic stress-strain of poured asphalt concrete are basically identical, consistent with a hyperbolic curve. The confining pressure and principal stress ratio significantly affect the backbone line of dynamic stress-strain. By comparison, frequency has a minimal effect. The changing trends of dynamic elasticity modulus and damping ratio of poured asphalt concrete under various factors are almost the same. When the material has high dynamic stress and strain, the hysteresis loop is large. When the curve of the damping ratio becomes flat, the asymptotic constant can be used as the maximum damping ratio. The relationship between the reciprocal of the dynamic elasticity modulus and the dynamic strain of poured asphalt concrete exhibits a linear distribution. Under different ratios of confining pressure to principal stress, there are large discrepancies between the calculated values from the formula and the experimental fitting values of the maximum dynamic elasticity modulus, and the maximum relative errors reach 16.65% and 18.15%, respectively. Therefore, the expression for the maximum dynamic elasticity modulus was modified, and the calculated values using the modified formula were compared with the experimental fitting values. The relative errors are significantly reduced, and the maximum relative errors are 3.02% and 2.04%, respectively, in good agreement with the fitting values of the experimental data. The findings of this article render a theoretical basis and reference for the promotion and application of poured asphalt concrete. [ABSTRACT FROM AUTHOR]

In the case of concrete built into a structure, the static secant modulus of elasticity (Ec,s) is often estimated based on its dynamic value (Ed) measured by the ultrasonic pulse velocity method instead of direct tests carried out on drilled cores. Meanwhile, the prevailing equations applied to estimate Ec,s often overlook the impact of concrete moisture. This study aimed to elucidate the moisture impact across two normal-weight structural concretes differing in compressive strength (51.6 and 71.4 MPa). The impact of moisture content was notably more evident only for the weaker concrete, according to dynamic modulus measurements. In other cases, contrary to the literature reports and expectations, this effect turned out to be insignificant. These observations may be explained by two factors: the relatively dense and homogeneous structure of tested concretes and reduced sensitivity of Ec,s measurements to concrete moisture condition compared to Ed measurements obtained using the ultrasonic method. Additionally, established formulas to estimate Ec,s were verified. The obtained modulus results tested under different moisture conditions of normal-weight concretes were also compared with those of lightweight aggregate concretes of identical volume compositions previously obtained in a separate study. [ABSTRACT FROM AUTHOR]

On the human face, the lips are one of the most important anatomical elements, both morphologically and functionally. Morphologically, they have a significant impact on aesthetics, and abnormal lip morphology causes sociopsychological problems. Functionally, they play a crucial role in breathing, articulation, feeding, and swallowing. An apparatus that can accurately and easily measure the elastic modulus of perioral tissues in clinical tests was developed, and its measurement sensitivity was evaluated. The apparatus is basically a uniaxial compression apparatus consisting of a force sensor and a displacement sensor. The displacement sensor works by enhancing the restoring force due to the deformation of soft materials. Using the apparatus, the force and the displacement were measured for polyurethane elastomers with various levels of softness, which are a model material of human tissues. The stress measured by the developed apparatus increased in proportion to Young's modulus, and was measured by the compression apparatus at the whole region of Young's modulus, indicating that the relation can be used for calibration. Clinical tests using the developed apparatus revealed that Young's moduli for upper lip, left cheek, and right cheek were evaluated to be 45, 4.0, and 9.9 kPa, respectively. In this paper, the advantages of this apparatus and the interpretation of the data obtained are discussed from the perspective of orthodontics. [ABSTRACT FROM AUTHOR]

The elastic moduli and thermal expansion of MoAlB, Fe2AlB2, and Mn2AlB2 are investigated by first‐principles calculations, in particular to improve the density functional theory (DFT) prediction accuracy after clarifying the critical role of their lattice constants. By calculating the lattice constants and elastic moduli using the typical exchange‐correlation functionals, the observed positive correlation between the calculation errors of elastic moduli and those of cell volumes suggests a method to significantly improve the calculation accuracy for elastic moduli using the experimental cell volume to correct the input model (volume correction method), resulting in satisfactory results. Furthermore, a two‐step strategy is proposed for the precise high‐temperature elastic moduli with the help of quasi‐harmonic approximation for the most accurate high‐temperature cell volume using an exchange‐correlation functional in the first step, and another one used in the volume correction method in the second step. Similarly, the calculation accuracy of thermal expansion also heavily depends on that of cell volumes and configurations, where their thermal expansion is estimated with great accuracy by using the exchange‐correlation functional that well reproduces the lattice constants. [ABSTRACT FROM AUTHOR]

This manuscript presents an experimental investigation of fly ash-based geopolymer-reinforced concrete beams' dynamic characteristics and mechanical properties. The purpose of this study is to compare the performance of geopolymer and portland cement concrete in terms of the viscous damping ratio, resonance frequency, compressive strength, and modulus of elasticity. The scope of the effort includes fabricating 14 reinforced concrete beams, 12 of which were made with geopolymer concrete and 2 with portland cement concrete. In this study, the experimental modal analysis method was employed. Test beams were placed on polyurethane cube supports to achieve free-free mode or oscillation conditions. For data analysis, 44 equally spaced analysis points were determined on the beams. Some of these points were stimulated five times along the x-x axis using a modal hammer to obtain FRF and viscous damping ratio graphs. As a result, the resonance frequency of portland cement concrete was higher than that of geopolymer concretes, while the viscous damping rate was lower. Furthermore, it was determined that the modulus of elasticity changed inversely with the viscous damping ratio rather than the compressive strength when examining the relationship between modal parameters and mechanical properties. These findings have significant implications for using geopolymer concrete in construction, as it can help distribute loads homogeneously and increase the durability of structures. Overall, this study provides valuable insights into the relationship between dynamic characteristics and mechanical properties of geopolymer and portland cement concrete, informing the development of more sustainable and resilient construction materials. [ABSTRACT FROM AUTHOR]

This study evaluated the impact of mutable water uptake on the durability of mechanical properties and the long-term reliability of artificial composites. Three resin-based CAD/CAM restorative materials (CRMs) were investigated in three-point bending tests to calculate flexural strength (FS), modulus of elasticity (ME), modulus of resilience (MR), modulus of toughness (MT), and elastic recovery (ER). All specimens (n = 180) were stored under the same conditions and tested in four subsets (n = 15 per material) that were respectively withdrawn after repeated thermocycling (5000 cycles; 5–55 °C, H 2 O) and repetitive drying (7 d; 37 °C, air). For every specimen, weight differences were determined per storage condition. Likewise, loss tangent data were separately recorded via dynamic mechanical analysis to reliably assess damping characteristics. Repeated thermocycling always induced weight increase and a concurrent significant loss in all mechanical properties except for MT and ER of a polymethylmethacrylate-based CRM. Drying consistently provoked weight loss and raised mechanical properties to initial values. Weight increase, however, enhanced loss tangent values and accordingly distinct damping characteristics, whereas weight decrease markedly lowered damping properties. Water uptake repeatedly induced a decrease in common mechanical properties but concurrently increased damping behavior. Invertible equilibrium processes were found with no evidence for permanent material degradation. [Display omitted] • Gain in CAD/CAM material water content raises weight and lowers mechanical properties. • Properties precisely recover after repetitive cycles of drying and water uptake. • Viscoelastic properties markedly increase in wet environment and enhance stability. • No detectable permanent mechanical property degradation is induced by water uptake. • Water uptake in CAD/CAM composites balances mechanical properties and induces damping. [ABSTRACT FROM AUTHOR]

This study focussed on the development of fully biodegradable composites based on polybutylene succinate (PBS) in combination with raw materials from different processing stages of the pulp and paper industry. Sulfite pulp (SP), kraft pulp (KP) and screened sludge residue (SL) from wastewater treatment plants (WWTP) were investigated as reinforcing fibres contributing to a circular economy. We report a comparative study of the physicochemical properties and mechanical performance of PBS composites reinforced with these cellulosic raw fibres and commercial pure microcrystalline cellulose (MC). The composites were characterised in tensile strength, elongation at break, modulus of elasticity, water absorption and wettability. The incorporation of the fibres into the polymer matrix was also investigated using torque rheometry. Critical concentrations were obtained with maximum incorporation in the range of 15–20 wt% for SP/KP and 25–30 wt% for SL. SP and KP composites showed at least as good physicochemical and mechanical properties as MC at the concentrations studied (0–20 wt%). SP-composites showed the highest tensile strength and modulus of elasticity. It was shown that these fibres from the pulp and paper industry can be used as reinforcement for PBS matrices without additional chemical purification and provide a valuable alternative to commercial microcrystalline cellulose. [ABSTRACT FROM AUTHOR]

Tropical hardwoods, often used as outdoor wood products, are frequently exposed to the hot and humid conditions in Malaysia. This has led to many studies attempting to develop suitable coatings and establishing maintenance cycles so that product service life can be extended. The objective of this study was to evaluate the surface quality and mechanical properties of both uncoated and coated three Malaysian hardwood species, namely dark red meranti (Shorea spp.), keruing (Dipterocarpus spp.) and keranji (Dialium spp.) after exposure to outdoor condition at different time spans. Surface quality of uncoated and coated with exterior transparent alkyd finished of the samples was evaluated visually as well as employing a profilometer-type equipment. Bending characteristics of outdoor exposed samples were also tested. The results showed that the surface of all coated samples degraded after 48 months of exposure. In addition, after 48 months of outdoor exposure, the modulus of rupture (MOR) values for dark red meranti, keruing and keranji decreased by more than 15% while the modulus of elasticity (MOE) values decreased by approximately 20% for both uncoated and coated samples. Generally, refinishing and maintenance should be performed within 2 years, and the cost of the maintenance should be calculated to ensure that the condition of the wood remains suitable for use as a building material in Malaysia's climate conditions. [ABSTRACT FROM AUTHOR]

The present study aims to investigate how the use of high‐range water reducer (HRWR) and variations in water/cement (W/C) ratio affect the properties of self‐consolidating concrete (SCC) while taking into account different proportions of polypropylene fibers (PF) and natural zeolite (NZ). A total of 28 samples were cast and analyzed. PF fractions ranging from 0% to 1.5% by weight were added, along with a substitution of 10% NZ for cement (50 kg/m3). Four W/C ratios (0.30, 0.35, 0.40, and 0.45) were tested, in addition to seven HRWR contents ranging from 5 to 6.5 kg/m3. Various tests were conducted to assess slump, T500, V‐funnel, L‐box, modulus of elasticity, and compressive, tensile, and flexural strengths. Novel models were developed to predict the properties of hardened concrete based on W/C, HRWR, PF, and NZ content. Findings indicated that optimal performance of PF‐reinforced SCC with NZ was achieved when up to 0.75% PF was combined with an HRWR content equivalent to 1.25% of the cement fraction and NZ ratio. Furthermore, the proposed models offer accurate predictions of both fresh and hardened‐state properties of PF‐reinforced SCC with NZ based on W/C and HRWR ratios. [ABSTRACT FROM AUTHOR]

Buried medium-density polyethylene pipes are conveniently used in gas distribution systems, particularly in areas subjected to ground movements, due to their flexible property to accommodate large deformation. The pipelines experiencing large ground movements require assessments for the fitness-for-services. Conventionally, the beam-on-spring idealization is used to evaluate pipelines exposed to ground movements. However, it is challenging for the beam-on-spring idealization to identify the spring parameters for representing soil–pipe interaction appropriately, which may vary from problem to problem. In the current study, three-dimensional (3D) finite element (FE) modeling was employed to understand soil–pipe interaction near the connection of a branch to a main pipe subjected to lateral movement. The FE model was developed through validation with full-scale test results. The study revealed that the conventional elastic–perfectly plastic model with a stress-dependent modulus of elasticity for soil could be reasonably used to simulate pipe–soil interaction observed during the tests. The FE analysis effectively simulated the mechanisms observed during the tests. Similar to the observations in the tests, the analysis calculated a lower pulling force yet higher strains for shallow buried pipes than for deeply buried pipes, confirming lower resistance to bending of the shallow buried pipes. The calculated contact pressures were nonuniform along the pipe length, indicating nonuniform axial and lateral soil resistances to the pipe. Thus, the spring forces recommended in the design guidelines should be revisited to account for the variation of contact pressure to model the pipe behavior using the conventional beam-on-spring analysis. Practical Applications: The outcomes of this research would apply to the integrity assessment of MDPE pipes in areas prone to ground movements. Pipes in a distribution network can experience additional stresses/strains due to ground movements, which should be evaluated for fitness-for-service assessment. This paper presents an assessment of pipe wall strains near a connection of a network branch. The understanding from this research would be useful for assessing pipes in the field under a similar ground movement scenario. [ABSTRACT FROM AUTHOR]

Plant seeds and fruits, like those of Ocimum basilicum , develop a mucilaginous envelope rich in pectins and cellulosic fibers upon hydration. This envelope promotes adhesion for attachment to soils and other substrates for dispersal and protection of the seed for a safe germination. Initially at hydration, the mucilage envelope demonstrates low adhesion and friction, but shows increasing adhesive and frictional properties during dehydration. However, the mechanisms underlying the cellulose fiber arrangement and the mechanical properties, especially the elasticity modulus of the mucilage envelope at different hydration conditions are not fully known. In this study, which is based on scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and light microscopy, the structure of the seed coat and arrangement of the cellulose fibers of basil seeds were characterized. Moreover, we performed pull-off force measurements to estimate adhesive properties and JKR-tests to estimate E-modulus of the mucilage at different hydration levels. Microscopy results demonstrate that cellulose fibers are split at their free ends into smaller fibrils, which might enhance the adhesive properties of the mucilage. Adhesive forces in contact increased during dehydration and reached maximum of 33 mN shortly before complete dehydration. The E-modulus of the mucilage changed from 1.4 KPa in water to up to 2.1 MPa in the mucilage at the maximum of its adhesion performance. Obtained results showed hydrogel-like mechanical properties during dehydration and cellulose fiber structures similar to the nanofibrous systems in other organisms with strong adhesive properties. This paper reveals the hierarchical cellulose fiber structure in Ocimum basilicum's mucilaginous seed coat, suggesting increased fiber splitting towards the end, potentially enhancing adhesion contact areas. Mechanical tests explore elasticity modulus and adhesion force during various hydration stages, crucial as these properties evolve with mucilage desiccation. A rare focus on mucilaginous seed coat mechanical properties, particularly cellulose-reinforced fibers, provides insight into the hydrogel-like mucilage of plant seeds. Adhesion forces peak just before complete desiccation and then decline rapidly. As mucilage water content decreases, the E-modulus rises, displaying hydrogel-like properties during early dehydration stages with higher water content. This study might bring the focus to plant seeds as inspiration for biodegradable glues and applications for hydrogel research. [Display omitted] [ABSTRACT FROM AUTHOR]