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The effect of shredded waste office paper was considered when producing one-layered particleboard. Five different mixing ratios of shredded waste office paper/wood particles were used (0/100, 25/75, 50/50, 75/25, and 100/0) and two amounts of urea formaldehyde (UF) resin (10% and 15%). The boards were tested for their physical and mechanical properties, including modulus of elasticity (MOE), bending strength (MOR), and internal bond (IB) strength, in accordance with the European Norm (EN) standards. All properties of the boards were found to be improved via increasing the resin content. The 15% UF-bonded board with 100% wood particles had the highest MOR, whereas the board containing 100% wastepaper for 15% UF had the highest MOE. However, there was no statistical difference between the board types. Although increasing wastepaper content in the board negatively affected the IB, the usage of wastepaper up to 25% was shown to be acceptable as a raw material in the production of particleboard. None of the prepared boards met the EN 312 (1999) requirements for thickness swelling. The boards made from shredded waste office paper were more suitable for dry and indoor use. [ABSTRACT FROM AUTHOR]

Paper aging and protection processes play an essential function in the preservation of library collections and archives. In this study, some physical-mechanical properties of paper samples from XXth century books (private collections), such as pH acidity, tensile strength, and modulus of elasticity, as well as optical properties, such as absolute change in yellowness, were examined before and after treating them with hydroxyapatite nanoparticles (HAp). Accelerated light aging was also evaluated and discussed. The treatment with HAp nanoparticles increased the paper’s pH to slightly alkaline values (approximately pH 8). Washing and treating the paper improved its mechanical properties compared to untreated paper; the tear length increased by 35% and the modulus of elasticity increased by 56%. That the treated and aged samples are more elastic than the original samples demonstrates that HAp nanoparticles consolidated the cellulose fibers. Additionally, particle morphology, size, composition and size distribution were assessed via image analysis using scanning electron microscopy (SEM-EDX), atomic force microscopy (AFM), and the ImageJ processing program.

Paper aging and protection processes play an essential function in the preservation of library collections and archives. In this study, some physical-mechanical properties of paper samples from XXth century books (private collections), such as pH acidity, tensile strength, and modulus of elasticity, as well as optical properties, such as absolute change in yellowness, were examined before and after treating them with hydroxyapatite nanoparticles (HAp). Accelerated light aging was also evaluated and discussed. The treatment with HAp nanoparticles increased the paper's pH to slightly alkaline values (approximately pH 8). Washing and treating the paper improved its mechanical properties compared to untreated paper; the tear length increased by 35% and the modulus of elasticity increased by 56%. That the treated and aged samples are more elastic than the original samples demonstrates that HAp nanoparticles consolidated the cellulose fibers. Additionally, particle morphology, size, composition and size distribution were assessed via image analysis using scanning electron microscopy (SEM-EDX), atomic force microscopy (AFM), and the ImageJ processing program. [ABSTRACT FROM AUTHOR]

Aggregate, sand, water and cement are the mixtures for concrete. Waste paper concrete (WPC) incorporates waste paper (WP) in a concrete mixture. Each year, WP production increases gradually. As a result, additional places are required for landfills, which consume energy, deplete natural resources and increase environmental pollution. The environmental pollution could be lessened by using WP in concrete. So, this comprehensive paper reviews the potential of WP by adding or substituting with fine aggregate, coarse aggregate and cement in concrete at 0%, 5%, 10%, 15% and 20%. This paper also reviews the WP's structures, physical and chemical properties. Moreover, the fresh, structural and durability properties of WPC, such as slump, modulus of elasticity, stress-strain and water absorption, are also reviewed in this paper. From this review, the concrete's fresh, structural, and durability properties increase with the incorporation of WP at 5% and 10% and decrease at more than 10%. There are some hydrated cement particles, as observed through the SEM. At 10% WP addition, the hydrated cement particles tend to increase the concrete strength more than the strength at 5% WP addition. It is apparent that the incorporation of WP brings significant desirable characteristics compared to ordinary concrete, which has no waste paper contents. WP can potentially have favourable properties to be used in concrete production by improving its properties and performance.

This paper presents manufacture and testing of paper boards made from recycled paper pulp. The aim was to create material for creating paper boards which could be used in furniture design with various shapes. The used types of pulp were deinked pulp (DIP) and old corrugated cardboards (OCC). Several test pieces - paper boards were made with different combinations of materials and its mechanical and physical properties were tested. The used glue for each material was urea formaldehyde glue and starch in combination with glucose. The tests which were done were determination of density and density profile (EN 323:2005), moisture content (EN 322:2005), modulus of elasticity in bending and bending strength (EN 310:1993), thickness swelling and water absorption (EN317:2005), internal bond (EN 319:2005) and screw withdrawal resistance (EN 320:2011). The aim was to create material for creating boards which could be used in furniture design with various shapes. The result of this paper shows possible material combinations which could be used for furniture parts. Paper boards will be used for table top of side table in following steps. [ABSTRACT FROM AUTHOR]

Due to the increasing accumulation of wastes around the world, the demand for sustainable products is increasing. Paper is a commonly disposed of material that can pose problems even when it is recycled. The concept of using cardboard (CB) as a material for furniture production has been around for many years, but CB furniture does not last long. This study examined the feasibility of using post-consumer recycled paper to produce paper-based boards for furniture design. Cardboard (CB) and office paper (OP) were the main post-consumer materials that were used. The CB and OP were mixed with polylactic acid (PLA) and limestone. The boards were made at a temperature of 200 °C and pressed at a pressure of 3.5 N/mm2 using a single opening hydraulic press. The physical and mechanical properties were tested according to the European standards for woodbased panels. Tests that are critical for furniture parts, such as the modulus of rupture (MOR), the modulus of elasticity (MOE), the internal bond, the screw withdrawal resistance, the thickness swelling, and the water absorption were examined. The paperboard samples exceeded some of the requirements for the general use of boards for interior fitments (including furniture) for use in dry conditions (Type P2) and for non-load bearing boards for use in humid conditions (Type P3). [ABSTRACT FROM AUTHOR]

Particleboards are extensively used in indoor applications due to their some advantages over massive wood. Particleboards, produced with formaldehyde-based adhesives or that kind of adhesives wastes (Urea-formaldehyde, Melamine-formaldehyde, melamine impregnated paper waste etc.), had high level formaldehyde emissions. In our recent study, particleboards, manufactured with MIP wastes as a resin replacement, showed much higher formaldehyde emission values than standard requirements and that motivated to perform this study. In this study, Amine based chemical mixture (ABCM) was used as a formaldehyde scavenger during particleboard manufacturing. Melamine impregnated paper wastes (MIPW) were used as adhesive. The effect of ABCM amounts on the formaldehyde content and other panel properties were investigated. Based on our previous findings, MIPW 25% was used for both core and surface layers. Five different rates of ABCM (0, 2.5, 5, 7.5 and 10%) were studied. Formaldehyde content was examined by perforator method according to EN 120. Furthermore, mechanical and physical properties including bending strength, modulus of elasticity, internal bond strength, surface soundness, screw withdrawal strength, thickness swelling and water absorption of the samples were determined according to EN 310, EN 319, EN 311, EN 320 and EN 317 standards, respectively. The experimentally results showed that, amount of ABCM had significant effect on formaldehyde content. With the increasing of ABCM rates, formaldehyde values was decreased. The usage of 10% ABCM provided the best results. All the tested boards had satisfied the standard requirements for mechanical and physical properties except thickness swelling and formaldehyde content. [ABSTRACT FROM AUTHOR]

Composite production of polypropylene polymers was considered in this work as the matrix, filled with the fiber of wheat straw and paper mill sludge; different ratios were evaluated relative to their potential as reinforcement materials. Maleic anhydride polypropylene (MAAP) was used at 3% by weight. The bending modulus of elasticity of the composites significantly increased with both types of filler. The highest bending modulus of the composites was found with 40% of paper mill sludge. Using 40% wheat straw fiber decreased bending strength, but the addition of paper mill sludge increased bending strength. The highest bending strength of the composites related to polypropylene/10% of wheat straw fiber and 30% of paper mill sludge. In terms of impact strength, the use of paper mill sludge had a higher impact on strength than wheat straw fiber composites. The inclusion of MAPP improved the mechanical properties of all composites. Scanning electron micrographs showed that the composite paper mill sludge improved the adhesion and dispersion of the filler (paper mill sludge/fiber paper instead of wheat) in the matrix. [ABSTRACT FROM AUTHOR]

The paper deals with the determination of the oxygen permeability and mechanical properties of butter and curd aluminium paper foils Radaflex applied in the food packaging. Foil Radaflex is a paper foil covered by the aluminium layer. The measurement of the oxygen permeability was realized according to the Standard STN EN 77 0333. The measurement of mechanical properties was realized according to the Standard STN EN ISO 1924-2. Determination of moduli of elasticity in the longitudinal and transversal direction were provided and tensile properties as maximal elongations, maximal tensile forces, tensile strengths, tensile indexes and strain at breaks of the longitudinal and transversal specimens were evaluated. The permeability of pure oxygen through aluminium paper foils was studied. Aluminium paper foil was not permeable for the oxygen.

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd 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 HOLOS is the property of Instituto Federal do Rio Grande do norte - IFRN 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.)

Preserving cultural artifacts while minimizing the energy consumption and costs associated with environmental control is crucial. This often requires predicting artifacts degradation caused by temperature and humidity. Here, mechanical damage can be predicted by comparing stress and damage criteria. Although the constitutive coefficients and damage criteria of various materials have been extensively studied, the mechanical properties of white clay remain unknown. This material is a crucial component of various artifacts including some important cultural artifacts and national treasures of Japan. Thus, this study aims to identify the strength and elastic properties of simulated white clay mimicking the substrate of the wall paintings Hiten at Kondo, the main hall at Horyu-ji Temple. Following existing literature, we created the simulated white clay by combining clay, paper fiber, and rice glue. We fabricated 36 distinct specimen patterns by varying the equilibrium humidity and material mixing ratios. We measured the tensile strength using splitting tensile tests and, compressive strength, Young's modulus, and Poisson's ratio using compressive tests. The tensile strength, compressive strength, Young's modulus, and Poisson's ratio ranged from 0.0785–1.17(MPa), 0.358–3.67(MPa), 0.0394–0.274 (GPa), and 0.10–0.44(-), respectively, with variations depending on the equilibrium humidity and ratio of material mixing. We also formulated the results as functions that depend on the equilibrium humidity and material mixing ratios. These findings can be used to predict stress and damage to targeted wall paintings and to inform the preservation and restoration of cultural artifacts containing white clay. [ABSTRACT FROM AUTHOR]

Due to the large increase in human population, the need for more buildings and other amenities is widening. Concrete is considered one of the most abundant and popular materials used in the structure and construction fields. It is known as a composite mix composed of cement and aggregates including fine and coarse and water. Despite its good properties, its capability to be formed in different shapes and its ability to resist severe conditions, concrete will struggle with the presence of extremely high temperatures. So, different types of concrete must be found to resist those challenging conditions. Refractory concrete can be considered a good choice to be used in places exposed to elevated temperatures and severe conditions. Mainly, refractory concrete is made up of ordinary Portland cement replacement well known as refractory cement, specific types of fine and coarse aggregates and are known as refractory or temperature-bearing aggregates and water. To the best authors' knowledge, review papers about refractory concrete are rare. For this reason, more than 65 papers were consulted including many recently published. This review describes the different types of materials used in refractory concrete. Furthermore, the different fresh, hardened, structural, durability and thermal properties of refractory concrete are also included such as slump, density, compressive strength, flexural strength, tensile strength, modulus of elasticity, ultrasonic pulse velocity, shrinkage, mass loss, porosity, water absorption, damage level and thermal conductivity. [ABSTRACT FROM AUTHOR]

The bending stiffness of pulp fibers in both dry and wet states is of great importance with respect to many optical and physical paper properties. We introduce a method that evaluates fiber bending stiffness from the fibers' Young's modulus (E) and the area moment of inertia (I) from the fiber cross section. The values for E and I in the dry state are obtained from single fiber tensile testing and image analysis of the fiber cross section. The values for the wet state are estimated from literature results for decreasing elastic modulus due to wetting and by the measurement of swollen, freezedried fiber cross sections by serial sectioning. We show a comparison between the results from our method and the bending stiffness of individual fibers measured with other methods. [ABSTRACT FROM AUTHOR]

Online sensing of sheet modulus of elasticity in the dry-end spans of printing grade paper machines (PMs) will permit the machine operators to control the mechanical properties of the produced paper. This paper develops an integrated sensorless tension control and sheet modulus of elasticity estimation algorithm, which is tested using field-recorded signals from a production PM and using a full model of the dry-end sections of this machine. Results show the ability of the proposed estimation algorithm to predict the sheet tension (tensile force) and sheet modulus of elasticity even in the presence of rapid changes in the speed and/or in other process operating conditions. The developed algorithms offer the papermaker new insights into the papermaking process. The ability to understand how modulus changes in real time provides a pathway to optimizing the operation of the PM drive system. [ABSTRACT FROM PUBLISHER]

Bulk metallic glasses (BMGs) are growing in popularity prominently due to their potential in micro-electromechanical systems (MEMSs) and aerospace applications. BMGs have unique mechanical properties, i.e., high strength, hardness, modulus of elasticity, and wear resistance, due to their disordered atomic structure. Due to their unique mechanical properties and amorphous structures, machining of BMGs remains a challenge. This paper aims to carry out a detailed literature review on various aspects of the machining of bulk metallic glasses using both conventional and non-conventional processes, including experimental approaches, modeling, statistical findings, challenges, and guidelines for machining this difficult-to-machine material. Conventional machining processes were found to be challenging for machining bulk metallic glasses due to their high hardness, brittleness, and tendency to convert their amorphous structure into a crystalline structure, especially at the machined surface and sub-surface. Although their high electrical conductivity makes them suitable for machining by non-conventional processes, they impose new challenges such as heat-affected zones and crystallization. Therefore, the successful machining of BMGs requires more in-depth analysis of cutting forces, tool wear, burr formation, surface finish, recast layers or heat-affected zones, crystallization, and mechanical property changes among different varieties of BMGs. This review paper provides guidelines emerging from in-depth analysis of previous studies, as well as offering directions for future research in the machining of BMGs. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) technology used for the design and production of porous implants can successfully address the issues of stress shielding and aseptic loosening associated with the use of solid implants in the human body. In this paper, orthogonal experiments were used to optimize the process parameters for SLM molding of Ti-6Al-4V (TC4) material to investigate the effects of the process parameters on the densities, microscopic morphology, and roughness, and to determine the optimal process parameters using the roughness as a judging criterion. Based on the optimized process parameters, the mechanical properties of SLM-formed TC4 alloy specimens are investigated experimentally in this paper. The main conclusions are as follows: the optimal combination of roughness is obtained by polar analysis, the microhardness of SLM-molded TC4 alloy molded specimens is more uniform, the microhardness of specimens on the side and the front as well as the abrasion resistance is higher than that of casting specimens, the yield strength and tensile strength of specimens is higher than that of ASTM F136 standard and casting standard but the elongation is not as good as that of the standard, and the elasticity and compressive strength of porous specimens are higher than that of casting specimens at different volume fractions. The modulus of elasticity and compressive strength are within the range of human skeletal requirements. This work makes it possible to fabricate high-performance porous femoral joint implants from TC4 alloy SLM-molded materials. [ABSTRACT FROM AUTHOR]

The potential of using residual softwood fibers from the pulp and paper industry for producing eco-friendly, zero-formaldehyde fiberboard panels, bonded with calcium lignosulfonate (CLS) as a lignin-based, formaldehyde free adhesive, was investigated in this work. Fiberboard panels were manufactured in the laboratory by applying CLS addition content ranging from 8% to 14% (on the dry fibers). The physical and mechanical properties of the developed composites, i.e., water absorption (WA), thickness swelling (TS), modulus of elasticity (MOE), bending strength (MOR), as well as the free formaldehyde emission, were evaluated according to the European norms. In general, only the composites, developed with 14% CLS content, exhibited MOE and MOR values, comparable with the standard requirements for medium-density fiberboards (MDF) for use in dry conditions. All laboratory-produced composites demonstrated significantly deteriorated moisture-related properties, i.e., WA (24 h) and TS (24 h), which is a major drawback. Noticeably, the fiberboards produced had a close-to-zero formaldehyde content, reaching the super E0 class (≤1.5 mg/100 g), with values, ranging from 0.8 mg/100 g to 1.1 mg/100 g, i.e., equivalent to formaldehyde emission of natural wood. The amount of CLS adhesive had no significant effect on formaldehyde content. [ABSTRACT FROM AUTHOR]

This paper proposes and evaluates a methodology for robust online estimation of the modulus of elasticity of an elastic strip transported through a multispan system. The estimation algorithm is based on a previously developed robust sensorless sheet-tension estimation and the computation of speed draws using 1024-pulse encoders operating in 4 x mode. The evaluation of the proposed algorithm was performed in the dry end of a lightweight coated paper machine. Results confirm the robustness of the online estimation and its ability in detecting rapid changes that may occur in the modulus of elasticity. The proposed algorithm will open new and interesting options for further improvements of the paper-making process. [ABSTRACT FROM AUTHOR]

Real-time estimation of the modulus of elasticity $(E)$ in paper machines would enable it to be controlled, improving final product quality and reducing the occurrence of sheet breaks. This paper develops a novel topology to estimate $E$ on web machines based on an adaptive observer structure that combines model reference adaptive control with a closed-loop observer using field signals such as tension force, velocity/position, and torque. The evaluation of the proposed topology is performed on the dryer–calender span of the dry-end section of a lightweight coated paper machine. Results show a fast and accurate estimation of $E$, confirming the robustness of the adaptive observer structure. [ABSTRACT FROM PUBLISHER]

Modern road construction uses a large number of polymer-based materials. Material composition depends on their roles. Among the most important functions of road body materials is to transfer all loads safely to the subgrade. A thorough understanding of material properties in various climates is crucial for this purpose. In the automotive industry, polymer residues from recycling can be used to make innovative materials, such as STERED, a hybrid polymer composite. Drawing on the porous nature of this material, this paper investigates its mechanical behavior. For road construction, the compressive properties of the material are most important. The paper presents the results of a detailed analysis and experimental research of the STERED material from in-lab tests. Successful research will lead to the inclusion of the material in road body compositions with excellent retention properties, vibration damping, and potential in circular economy. [ABSTRACT FROM AUTHOR]

Assessing the constrained modulus is a critical step in calculating settlements in granular soils. This paper describes a novel concept of how the constrained modulus can be derived from seismic tests. The advantages and limitations of seismic laboratory and field tests are addressed. Based on a comprehensive review of laboratory resonant column and torsional shear tests, the most important parameters affecting the shear modulus, such as shear strain and confining stress, are defined quantitatively. Also, Poisson's ratio, which is needed to convert shear modulus to constrained modulus, is strain-dependent. An empirical relationship is presented from which the variation in the secant shear modulus with shear strain can be defined numerically within a broad strain range (10−4–10−0.5%). The tangent shear modulus was obtained by differentiating the secant shear modulus. According to the tangent modulus concept, the tangent constrained modulus is governed by the modulus number, m, and the stress exponent, j. Laboratory test results on granular soils are reviewed, based on which it is possible to estimate the modulus number during virgin loading and unloading/reloading. A correlation is proposed between the small-strain shear modulus, G0, and the modulus number, m. The modulus number can also be derived from static cone penetration tests, provided that the cone resistance is adjusted with respect to the mean effective stress. In a companion paper, the concepts presented in this paper are applied to data from an experimental site, where different types of seismic tests and cone penetration tests were performed. [ABSTRACT FROM AUTHOR]

Medium density fiberboard (MDF) is widely utilized in furniture production. Most MDF in such applications has a surface laminate layer. The lamination process improves the physical and mechanical properties of the boards. The temperature, press time, and pressure values applied during the lamination process affect such properties. In this work, the lamination process was carried out using a constant temperature (180 °C), four different press times (18, 20, 22, and 24 s), and three different pressures (25, 30, and 35 kg/cm²). The raw weight of the decor paper was 90 g/m² and UF and MF glues were used in its production. The properties of the laminated panels were then determined for each variation. In general, the water absorption and thickness swelling properties were improved at the lower pressure and higher press times. The internal bonding strength exhibited a linear change at different press times depending on increasing pressure values, whereas the changes in the bending strength and modulus of elasticity in bending were not statistically significant. It was concluded that the BS increased with rising pressure in the short-term lamination process and that the effect of the pressure on the BS declined with increasing press time. [ABSTRACT FROM AUTHOR]

Weathering processes gradually alter the physical and mechanical attributes of slope materials, weakening the structural integrity and stability of slopes. This paper presents an in-depth analysis of slope stability in an open-pit mine, emphasizing the pivotal role of weathering effects in determining slope stability. To accurately capture the impact of weathering on slope stability, a comprehensive analysis model was developed, incorporating field observations, laboratory testing, and numerical simulations. The effects of weathering on the mechanical properties of black shale were studied through extensive laboratory tests. The uniaxial compressive strength, shear strength, and modulus of elasticity significantly decreased with increasing weathering, indicating a heightened vulnerability to slope failure. The correlation function between mechanical parameters and weathering time was obtained, providing the basis for evaluating the stability of mine slopes. It was found that more severe weathering conditions were strongly correlated with elevated risks of slope failure, including landslides and collapses. Based on these findings, practical recommendations are provided for slope reinforcement and management strategies, aimed at mitigating slope failure risks and ensuring the safe and efficient operation of the mine. By incorporating weathering effects into slope stability analysis, mine operators can make informed decisions that account for the dynamic nature of slope materials and their susceptibility to weathering, thereby improving overall mine performance and safety. [ABSTRACT FROM AUTHOR]

In this paper, the effect of basalt fiber (BF) on the frost resistance of concrete under different curing conditions was investigated, and its frost resistance mechanism was analyzed. Three different curing conditions (normal curing, short-term curing, and seawater curing) were adopted, and concrete with different BF volume contents was designed. Freeze-thaw (FT) tests were carried out using the rapid freezing method to test the frost resistance of basalt fiber reinforced concrete (BFRC). Additionally, the mass loss rate (MLR), relative dynamic modulus of elasticity (RDME) change, and compressive strength reduction of specimens during the freeze-thaw cycles (FTCs) were evaluated. The results show that when the BF content is 0.15%, under normal curing, short-term curing, and seawater curing conditions, the residual compressive strength of BFRC after FTCs was increased by 5.4%, 28.1%, and 30.9%, respectively, compared to plain concrete. By incorporating BF into concrete, the development of microcracks can be effectively retarded, and damage generation during FTCs can be reduced. In addition, the microscopic morphological characteristics and pore structure characteristics of concrete further elucidate the frost resistance mechanism of BFRC from a microscopic perspective. [ABSTRACT FROM AUTHOR]

To date, composite materials, such as polymer concrete, have found wide application in various industries due to their unique properties combining high strength, resistance to aggressive media and durability. Improving the performance characteristics of polymer concrete is an important task aimed at expanding the areas of its application. One of the promising methods of increasing the strength of this material is the use of various fillers. In this paper, the effect of fillers, based on carbon and basalt fibres, on the mechanical properties of polymer concrete was investigated. The polymer concrete was made of the following components: rubble stone, sand, quartz flour and polyester resin. During the experimental work, the amount of carbon and basalt fibres in the polymer concrete mixture varied from 0 to 6%. Bending and compressive strength tests showed that the addition of carbon and basalt fibres increased these properties. The highest bending and compressive strengths were achieved when carbon fibre contents were up to 1.5%, while basalt fibres provided the highest strengths in the case of around 2%. These results confirmed that carbon fibres had a higher efficiency in strengthening polymer concrete compared to that of basalt fibres. This could be explained by the fact that carbon fibres had a higher tensile strength and modulus of elasticity, which allowed them to better redistribute loads within the composite material. The fibre length for carbon fibre, which gave the maximum increase in properties, was 10–15 mm. For basalt fibre, the maximum bending strength was reached at 20 mm and compressive strength at 10 mm. Increasing the content of carbon fibre above 2% and basalt fibre above 1.5% did not give further increase in mechanical properties. In conclusion, it could be stated that the use of carbon fibres as fillers offered significant advantages in strengthening polymer concrete, opening up opportunities for its use in more demanding conditions and in a wider range of industrial applications. [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]

This paper presents a thorough reliability assessment of cavity foundation systems involving the generation of 272 datasets using Plaxis 2D automation. The parameters were systematically varied across feasible ranges, and Sobol‐based sensitivity analysis identified the negligible influence of the soil modulus of elasticity (E) on subsequent reliability analyses. A robust 1D‐CNN surrogate model was developed to predict the critical foundation responses by integrating Gaussian white noise to simulate real‐world uncertainties. A log transformation with 1,000 bootstrap samples was chosen for resampling non‐normally distributed data. This study employed a novel approach utilising 1D‐CNN regressor models for bearing capacity (BC) prediction, achieving promising results with R2 values of 0.953 and 0.945 for BC in the training and testing phases, respectively. Bootstrapping resampling facilitates reliability analysis preparation and ensures robustness in handling complex data. Simulated noise varied with specific variance (p) from 0.01 to 0.5, allowing the examination of model efficacy under varying noise levels. Both the Monte Carlo Simulation (MCS) and first‐order reliability method (FORM) were employed, revealing a reliability index (β) of 2.046 for FORM and 2.066 for MCS. This indicates a 0.976% increase in β and a 75% increase in the probability of failure transitioning from FORM to MCS, underscoring the model's sensitivity to analytical methods. [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]

Research results on the improvement of the strength properties of a testliner produced from recovered paper and kraft pulp are presented in this work. The effects of kraft pulp content and the fractionation of secondary fiber on testliner strength properties were determined. Primary and recovered paper pulp was produced using standard procedures. The testliner consisted of three layers, totaling a grammage of 150 g/m2, when the center layer was made solely from the short fiber fraction of recovered paper. The weight of the surface layers each comprised 30% of the total handsheet weight, and the center layer weight was 40%. The virgin fiber content of the upper and lower layers was varied from 0% to 30% of the corresponding handsheet layer weight. The breaking length, tensile strength, modulus of elasticity, longitudinal and bending rigidity, and bursting and plybond strength, along with the effects of virgin fiber dosage on the strength properties were experimentally determined. As a result, a composition was proposed that showed the rational arrangement of virgin fibers as well as short- and long-fiber fractions of recovered paper in the layers. A comparison of the strength properties of the testliner using standard parameters demonstrated the advantages of the testliner producing technology. [ABSTRACT FROM AUTHOR]

This paper addresses the challenges associated with steel pipes used for transporting liquid fluids within buried sections of mining facilities, specifically in areas with heavy mining vehicles. While existing design standards, such as AW-WA M11, and manufacturer recommendations largely consider loads from vehicles like the AASHTO HS20 or Cooper E-80, both weighing below 35 tons, these guidelines inadequately represent the actual loads experienced on certain mining roads, notably those accommodating heavy vehicles, like haul roads. The research presented here focuses on the interaction between soil and buried steel pipes under the substantial loads exerted by mining vehicles with a maximum gross load of up to 612 tons, inclusive of hauled material weight. Utilizing a parametric study with the finite element method, the paper identifies critical variables influencing efforts and deflections calculations in these facilities. The analysis of 108 models, varying parameters related to trench pipe installation conditions, offers insights that empower designers to refine soil trench parameters in mining facilities, mitigating pipe failures and optimizing installation costs. Ultimately, the key influential variables affecting pipe deflection and stress are identified as the trench backfill height and the elasticity modulus of the trench lateral fill. [ABSTRACT FROM AUTHOR]

Glue laminated bamboo (glubam) is a type of engineered bamboo material developed for applications in building structures and interiors. This paper focuses on the fungal (Aspergillus niger) colonization from 14 to 56 days in thick- and thin-strip glubam board with the investigation of physical, mechanical (compression), and microcosmic properties. Two-degree of carbonization treatment was employed to improve the antifungal property of the thick-strip glubam. After 56 days of infection, the deep-degree carbonized thick-strip glubam presents better anti-mold properties than medium and non-carbonized specimens. For thin-strip glubam, both parallel and perpendicular to the main bamboo fiber direction were considered. The longitudinal thin-strip glubam retains decent compressive properties, while the transverse specimens stay a stable compressive strength along all fungal tests. The paper reports the experimental values of mass loss, color changes, compressive strengths, modulus of elasticity in compression, and microstructure observations from optical and SEM microscopy at different fungal exposure timespans. [ABSTRACT FROM AUTHOR]

The stability assessment of loess slopes is of great significance for slope reinforcement and safety assessment. This research studies the main factors affecting the stability of the loess slope through the summary and analyzes the failure cases of the loess slope in Shaanxi Province. The importance of influencing factors was studied through numerical simulation method, sensitivity analysis method, and gray correlation analysis method, and the weight value method was given. On this basis, we have developed the fuzzy comprehensive evaluation model method for assessing the stability of loess slopes based on the principle of maximum membership degree. Finally, the method was applied to the stability analysis of the actual loess slope, and the rationality and correctness of the loess slope stability evaluation method proposed in this paper were demonstrated. The results showed that, for the Shaanxi loess slope, the probability of instability of the positive slopes is far greater than that of negative slopes; the greater the slope gradient, the more unstable the loess slopes. Collapse mainly occurs in the range of 10–40 m slope height. There is a significant positive correlation between rainfall and the probability of loess landslides. The degree of correlation between the factors influencing slope stability and the safety factor can be categorized from strong to weak as follows: slope inclination > internal friction angle > height of the slope > gravitational forces > cohesion > Poisson's ratio > modulus of elasticity, and the influence of Poisson's ratio and elastic modulus can be ignored. The fuzzy comprehensive evaluation method based on the gray correlation degree method established in this paper was used to evaluate the stability of the loess slopes. The evaluation results attested to the actual data of slope monitoring. The evaluation method proves reasonable and feasible and can be well applied to the stability analysis of the loess slopes. [ABSTRACT FROM AUTHOR]

The effects of the exposure to elevated temperatures on the mechanical performances of a PBO FRCM (fabric reinforced cementitious matrix) composite system, consisting of polypara-phenylene-benzo-bisthiazole (PBO) fiber meshes embedded into an inorganic mortar, widely used in the strengthening of existing degraded reinforced concrete structures, are analyzed and discussed in the paper. The residual tensile properties of PBO FRCM composites and the residual bond properties of PBO FRCM-to-concrete are analyzed through the results of an experimental investigation conducted on specimens subjected to heating-cooling regimes at temperatures ranging from 20°C to 300°C, and then tested at ambient temperature (20°C). Direct tensile (DT) tests on PBO FRCM coupons and direct single lap shear (DS) tests on PBO FRCM-concrete elements were performed. The parameter varied was the target temperature value, namely 20°C, 100°C, 200°C, and 300°C. Test results are reported in terms of cracking stress, tensile strength, ultimate tensile strain, uncracked and cracked elasticity moduli, failure mode, bond strength, and corresponding slip values. The obtained results are evidence that the effects of exposure at the target temperatures were different for each mechanical parameter. Significant reductions of the values measured at ambient temperature were observed only at 300°C. Temperature-dependent relationships for both tensile and bond mechanical parameters, useful for thermo-mechanical simulations and fire design of reinforced concrete structures strengthened with PBO FRCM composites, are also defined. Finally, the results of a comparative analysis between the experimental results described in the present paper and those available in the literature are reported and discussed. [ABSTRACT FROM AUTHOR]

Purpose: Hepatocellular carcinoma (HCC) is one of the most common types of liver cancer that could potentially be surrounded by healthy arteries or veins that a surgeon would have to avoid during treatment. A realistic 3D liver model is an unmet need for HCC preoperative planning. Methods: This paper presents a method to create a soft phantom model of the human liver with the help of a 3D-printed mold, silicone, ballistic gel, and a blender. Results: For silicone, the elastic modulus of seven different ratios of base silicone and silicone hardener are tested; while for ballistic gel, a model using 20% gelatin and 10% gelatin is created for the tumor and the rest of the liver, respectively. It is found that the silicone modulus of elasticity matches with the real liver modulus of elasticity. It is also found that the 10% gelatin part of the ballistic gel model is an excellent emulation of a healthy human liver. Conclusion: The 3D flexible liver phantom made from a 10% gelatin-to-water mixture demonstrates decent fidelity to real liver tissue in terms of texture and elasticity. It holds significant potential for improving medical training, preoperative planning, and surgical research. We believe that continued development and validation of such models could further enhance their utility and impact in the field of hepatobiliary treatment planning and education. [ABSTRACT FROM AUTHOR]

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

This paper innovatively proposes a method of 180 °C high-temperature stirring pretreatment for waste rubber particles and compares this method with untreated, NaOH-treated, and silane coupling agent KH570-treated waste rubber particles. Fourier-transform infrared spectroscopy, X-ray diffraction analysis, water contact angle measurement, scanning electron microscopy, and energy-dispersive X-ray study are used to investigate the effects and mechanisms of different pretreatment methods on waste rubber particles. The results indicate that compared to NaOH-treated and KH570-treated waste rubber particles, the 180 °C high-temperature-stirred pretreated waste rubber particles show significantly improved cleanliness and form a hard oxide film. The study also investigates the effects of different pretreatment methods on the mechanical properties and interface binding performance of rubber concrete made from pretreated waste rubber particles. The results demonstrate that rubber concrete prepared using 180 °C high-temperature-stirred pretreated waste rubber particles substituting 20% fine aggregate exhibits the best mechanical properties and interface bonding performance. The compressive strength recovery rates after 7 and 28 days are 41.6% and 37.3%, respectively; the split tensile strength recovery rates are 47.3% and 60.6%; the axial compressive strength recovery rates are 34.1% and 18.8%; and the static compression moduli of elasticity recovery rates are 46.8% and 26.3%. High-temperature stirring pretreatment of waste rubber particles is simple to operate and suitable for scaled production. Its pretreatment effect is superior to those of the KH570 and NaOH methods, providing a reference value for the scalable application of waste rubber particles as a substitute for fine aggregate in rubber concrete. [ABSTRACT FROM AUTHOR]

The load-bearing capacity of a building is influenced by the strength of the concrete. However, when faced with complex environments, ordinary concrete is not always adequate. The strength of concrete can be enhanced by incorporating additives into it. At this point, the study of adding basalt fiber (BF) and nano-SiO2 (NS) to concrete is pretty advanced. Still, research on the incorporation of nano-TiC (NT) into concrete is limited. In order to study the effect of NT, BF, and NS on the strength of concrete, in this paper, these materials were incorporated into concrete and NSF concrete was made by semi-dry mixing. And the concrete was analyzed for slump, compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity. The optimization of the mechanical characteristics of concrete was conducted using response surface methodology (RSM), and the microstructure of concrete was used for analysis by scanning electron microscopy (SEM). To develop a thirst function optimization model based on NSF concrete, parallel experiments were used to verify the accuracy of the optimization results. The research findings show that NS, NT, and BF reduced the slump of concrete. Adding NT, NS, and BF in moderate amounts can enhance the mechanical characteristics of the concrete. The material's optimal proportions for mixing were 0.85% for NT, 0.11% for BF, and 1.94% for NS. The optimized concrete has a maximum error of 9.03% in compressive strength, 9.30% in split tensile strength, and 9.82% in flexural strength. [ABSTRACT FROM AUTHOR]

The method of segmented hydraulic fracturing in the coal seam roof has proven to be an efficient technique for coalbed methane exploitation. However, the behavior of hydraulic fractures in multilayer formations with significant differences in mechanical properties is still unclear. This paper studied the variation in hydraulic fracture width at the coal-rock interface by employing experimental method with a true triaxial hydraulic fracturing experimental system and numerical simulation method. Results revealed that the hydraulic fracture more likely to expanded along the coal-rock interface instead of break through it with the small horizontal stress difference and low flow rate injection condition. And improving the injection flow rate lager than a critical value, the hydraulic fracture tends to break through the coal-rock interface. Hydraulic fractures in both mudstone and coal beds exhibited a trend of increasing and then decreasing of fracture width at the interface. Since the strength of the coal seam was lower compared to that of the mudstone, maintaining high pressure was no longer necessary when the hydraulic fracture crossed the interface and entered the coal seam, leading to a reduction in fracture width within the mudstone. During the later stages of fracturing, the entry of proppant into the coal seam became challenging, resulting in a phenomenon characterized by excessive fluid but insufficient sand. The time required for the fracture width to traverse the proppant was found to be inversely proportional to the difference in horizontal ground stress and the flow rate of the fracturing fluid. And it was directly proportional to the modulus of elasticity, permeability of the coal seam, and interface strength. The interface strength has the greatest influence on the width of hydraulic fractures. In conclusion, this study provides valuable insights into the behavior of hydraulic fractures in multilayer formations with varying mechanical properties. The findings contribute to a better understanding of the factors affecting hydraulic fracture width within coal seams, which can ultimately enhance the efficiency of coalbed methane exploitation. [ABSTRACT FROM AUTHOR]

Trembling aspen (Populus tremuloides) is one of the major species within Populus, a predominant genus of hardwoods in North America. However, its utilization has been limited to pulp and paper or wood-based composite boards. This study aimed at evaluating the major physical and mechanical properties of trembling aspen lumber, with an ultimate objective of using this species to produce engineered wood products (EWPs). The testing materials consisted of 2 × 4 (38 mm × 89 mm) trembling aspen lumber pieces in lengths of 8, 10, and 12 feet (2.44, 3.05, and 3.66 m) with two visual grades, select structural (SS) and No. 2. Machine Stress-Rated (MSR), and longitudinal stress wave (LSW), edgewise third-point bending (EWB), and axial tension tests were conducted on the lumber. It was found that, (1) by increasing the maximum knot size by a half-inch from one-quarter inch, the minimum modulus of elasticity (MOE) measured using the MSR, the mean, and the fifth-percentile ultimate tensile strength (UTS) decreased by about 8.8%, 20.1%, and 29.8%, respectively. (2) Approximately 44% of the trembling aspen lumber met the 1450f-1.3E grade for MSR lumber, and 62% qualified for the 1200f-1.2E grade. (3) There was a great potential for manufacturing cross-laminated timber (CLT) of grade E3, with a rejection rate of about 29%. (4) The mean UTS and MOE values of the SS-grade trembling aspen lumber were 22.88 MPa and 9519 MPa, respectively, being 25.5% and 11.3% lower than that of Spruce–Pine–Fir (S-P-F) lumber. The fifth-percentile UTS and MOE values were 11.57 MPa and 7404 MPa, respectively, marking a decrease of 13.3% and 1.5% compared to the S-P-F lumber. (5) The oven-dried specific gravity (SG) of the trembling aspen wood was 0.40, which was about 3.5% larger than the value provided in the Wood Handbook. [ABSTRACT FROM AUTHOR]

In this paper, steel fiber coal gangue concrete is examined for its fire resistance, high strength, and stability, aiming to achieve both green sustainability and resistance to elevated temperatures. We conducted tests on concrete specimens with varying coal gangue aggregate volume replacement rates (0%, 20%, 40%, 60%) and steel fiber volume contents (0%, 0.5%, 1.0%, 1.5%) to assess their post-high-temperature mechanical properties. These tests were performed at five temperature levels: 20 °C, 200 °C, 400 °C, 600 °C, and 800 °C. The focus was on analyzing the residual mechanical properties and constitutive relationship of the steel fiber coal gangue concrete after exposure to high temperatures. The findings indicate that as the temperature rises, the compressive strength, split tensile strength, and modulus of elasticity of the steel fiber coal gangue concrete specimens undergo varying degrees of reduction. However, the peak strain and ultimate strain increase gradually. The incorporation of steel fibers enhances the mechanical properties of the coal gangue concrete, resulting in improvements in the elastic modulus and peak strain, both before and after exposure to high temperatures. Furthermore, the established constitutive relationship for steel fiber coal gangue concrete after high temperatures, derived from calculations and validated with experimental data, provides a more accurate representation of the entire damage process under uniaxial compressive loading at elevated temperatures. [ABSTRACT FROM AUTHOR]

Rock strength parameters such as uniaxial compressive strength and modulus of elasticity are crucial parameters in designing rock engineering structures. Owing to the importance of the aforementioned parameters, in this paper, image processing technique is coupled with artificial neural network (ANN) method for assessing the uniaxial compressive strength and modulus of elasticity of sandstones. For this reason, 102 core sandstone samples were prepared. Subsequently petrographic analyses and imaging operation for 102 images were performed. Principal component analysis was then conducted for feature reduction purposes. At last, an ANN model, which received its input data from image processing technique, was constructed for assessing the UCS and E of sandstone samples. Overall, the best performance of the network was obtained when 10 hidden nodes were used. The correlation coefficient (R) values of 0.9722 and 0.97062 for UCS and E, respectively, suggest the feasibility of the proposed model. [ABSTRACT FROM AUTHOR]

The reasonable and effective application of waste tires and discarded concrete in concrete is an important branch of green concrete development. This paper investigates the effects of the inorganic modification mode on the basic mechanical properties of rubber recycled concrete based on indoor tests. Inorganic modification, such as water washing, acid washing, and alkaline washing modification, was mainly used to treat and modify rubber particles. The factors affecting the compressive strength, the splitting tensile strength, the flexural strength, the axial compressive strength, and the modulus of elasticity of modified rubber recycled concrete were analyzed. The study results show that the incorporation of recycled aggregates and rubber reduced the mechanical properties of concrete, with the compressive and splitting tensile strengths showing the greatest reductions of 27.36% and 27.24%, respectively. Three modification methods significantly improved the mechanical properties of rubber recycled concrete. The alkali washing modification method was the most effective, maximally improving the mechanical properties of rubber recycled concrete by 7.53–15.51%. The effects of the three modifications on the mechanical properties of concrete were ranked as follows: alkali washing > acid washing > water washing. This study provides a data basis for the practical application of rubber recycled concrete in engineering and a test basis for the development of green concrete. [ABSTRACT FROM AUTHOR]

In spite of its intrinsic complexities, the passive gait of bipedal robots on a sloping ramp is a subject of interest for numerous researchers. What distinguishes the present research from similar works is the consideration of flexibility in the constituent links of this type of robotic systems. This is not a far-fetched assumption because in the transient (impact) phase, due to the impulsive forces which are applied to the system, the likelihood of exciting the vibration modes increases considerably. Moreover, the human leg bones that are involved in walking are supported by viscoelastic muscles and ligaments. Therefore, for achieving more exact results, it is essential to model the robot links with viscoelastic properties. To this end, the Gibbs-Appell formulation and Newton's kinematic impact law are used to derive the most general form of the system's dynamic equations in the swing and transient phases of motion. The most important issue in the passive walking motion of bipedal robots is the determination of the initial robot configuration with which the system could accomplish a periodic and stable gait solely under the effect of gravitational force. The extremely unstable nature of the system studied in this paper and the vibrations caused by the impulsive forces induced by the impact of robot feet with the inclined surface are some of the very serious challenges encountered for achieving the above-mentioned goal. To overcome such challenges, an innovative method that uses a combination of the linearized equations of motion in the swing phase and the algebraic motion equations in the transition phase is presented in this paper to obtain an eigenvalue problem. By solving this problem, the suitable initial conditions that are necessary for the passive gait of this bipedal robot on a sloping surface are determined. The effects of the characteristic parameters of elastic links including the modulus of elasticity and the Kelvin-Voigt coefficient on the walking stability of this type of robotic systems are also studied. The findings of this parametric study reveal that the increase in the Kelvin-Voigt coefficient enhances the stability of the robotic system, while the increase in the modulus of elasticity has an opposite effect. [ABSTRACT FROM AUTHOR]

Silver birch, a widely distributed deciduous tree native to Europe, is valued for its wood applications in construction, furniture making, and paper production. In Lithuania, silver birch ranks as the third most common forest-tree species, comprising 22% of the forested areas, and is an important species for tree breeding due to its potential and adaptability. This study was focused on assessing the mechanical properties of wood (sample and log hardness, wood density, dynamic modulus of elasticity (MOEdyn), static modulus of elasticity (MOE) and bending strength (MOR)) in silver birch (Betula pendula L. Roth.) trees from different half-sibling families. Two experimental plantations of the progenies of Lithuanian populations (half-sib families) of silver birch from different regions were analysed. From these plantations, four genetic families were selected for mechanical properties evaluation. The study findings revealed significant variability in various wood properties among different genetic families, although the static modulus of elasticity did not exhibit significant differences between the chosen genetic families. All measured wood properties decreased from the bottom to the top of the model trees. Wood hardness displayed a moderately negative correlation for wood density and weak correlations for MOE and MOR. Given the weak correlations between wood hardness and other wood mechanical properties, it is suggested that MOEdyn would be a more suitable trait for genetic studies. [ABSTRACT FROM AUTHOR]

Wood is an orthotropic material used since ancient time. A literature research about the mechanical properties of density, fracture toughness, modulus of elasticity, and Poisson's ratio has been done to have a broader view on the subject. The publications relating to the topic were found through the two search engines Scopus and Google Scholar that have yielded several papers, including articles and book sections. In general, there is no standardization on the method of analysis carried out on wood, underlining the great difficulty in studying this complex material. The parameter of density has a great variability and needs a deeper investigation; fracture toughness is not always available in literature, not even in the different directions of the wood sample. Interesting is the modulus of elasticity, which provides a correlation with density, especially in longitudinal section but, again, it needs to be studied in detail. The parameter of Poisson's ratio is provided as single values in three different directions, but mainly for softwood. All the parameters require a more in-depth study for both softwood and hardwood. Furthermore, the type of analysis, whether experimental or modelling, needs to be standardized to have more comparable results. [ABSTRACT FROM AUTHOR]

The paper attempts to estimate the profitability of combining wood and CFRP into a composite (BSH-CFRP), intended to be used in load-bearing beams, including mechanical performance and prices of constituent materials. Prices of glue laminated timber (BSH) and CFRP tapes over the years were provided by ABIES Poland Ltd. and S&P Poland Ltd. companies. Referring to the uncertainty of wood prices on the market, two levels of BSH prices were adopted. A prediction of the beams' mechanical behaviour was made based on the analytical model prepared by the author. The calculated members varied in width, height and length and included twelve types of CFRP tapes (different thickness, width and modulus of elasticity) glued between wooden lamellas. The total cost of each BSH-CFRP beam was compared to the total cost of the corresponding BSH beam in GL24h class, which led to calculating a cost multiplier. Consecutively, the multiplier was referred to the standard class improvement of BSH according to the bending stiffness and load-bearing capacity. A cloud of points got from many analyses resulted in obtaining exponential approximating functions. The averaged results led to general conclusions that at the assumed price level, improving the BSH standard class by using CFRP tapes was associated with a 1.86 BSH cost in the case of expensive wood or 2.81 in the case of cheap wood. Improving class by two was connected with the 3.55 BSH cost for expensive wood, and 6.79 for cheap wood. At present, the profits from composing wood with CFRP appear to be not very high in terms of their price. However, they can radically increase, especially when wood cutting limits are imposed on manufacturing companies, which significantly reduce the available timber for construction use. [ABSTRACT FROM AUTHOR]

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The physical and mechanical properties of heat-treated wood are essential factors in assessing its appropriateness for different applications. While back-propagation (BP) neural networks are widely used for predicting wood properties, their accuracy often falls short of expectations. This paper introduces an improved Beluga Whale Optimisation (IBWO)-BP model as a solution to this challenge. We improved the standard Beluga Whale Optimisation (BWO) algorithm in three ways: (1) use Bernoulli chaos mapping to explore the entire search space during population initialization; (2) incorporate the position update formula of the Firefly Algorithm (FA) to improve the position update strategy and convergence speed; (3) apply the opposition-based learning based on the lens imaging (lensOBL) mechanism to the optimal individual, which prevents the algorithm from getting stuck in local optima during each iteration. Subsequently, we adjusted the weights and thresholds of the BP model, deploying the IBWO approach. Ultimately, we employ the IBWO-BP model to predict the swelling and shrinkage ratio of air-dry volume, as well as the modulus of elasticity (MOE) and bending strength (MOR) of heat-treated wood. The benefit of IBWO is demonstrated through comparison with other meta-heuristic algorithms (MHAs). When compared to earlier prediction models, the results revealed that the mean square error (MSE) decreased by 39.7%, the root mean square error (RMSE) by 22.4%, the mean absolute percentage error (MAPE) by 9.8%, the mean absolute error (MAE) by 31.5%, and the standard deviation (STD) by 18.9%. Therefore, this model has excellent generalisation ability and relatively good prediction accuracy. [ABSTRACT FROM AUTHOR]