Elastic Modulus Research Articles

Shear Wave Elastography as an Supplement Tool in Differentiating Benign and Malignant Axillary Lymph Nodes.

To determine the efficacy of quantitative shear wave elastography in differentiating benign and malignant axillary lymph nodes (ALN). Exactly 127 lymph nodes from 127 patients with clinically palpable axillary swelling were examined by both B-mode sonography and elastography from November 2022 to March 2024. Gray-scale sonograms were evaluated based on: the short-axis diameter, shape, hilum, maximum cortical thickness, and border of the ALN. Shear wave elastography determined the mean elasticity modulus (E-mean) and elasticity ratio (E-ratio). Fine needle aspiration cytology or histopathological examination was kept as the gold standard and diagnostic performance shear wave elastography was compared. The data showed that out of 127 lymph nodes, 77 (60.6%) were benign and 50 (39.4%) were malignant based on pathological results. The E-mean for malignant lymph nodes (mean, 73.15 kPa) was higher than that for benign lymph nodes (mean, 21.47 kPa; P < .001). The area under the receiver operating characteristic curve for E-ratio in predicting malignant and benign lymph nodes was 0.897 (95% CI: 0.839-0.955). The E-ratio for malignant lymph nodes was also higher (mean, 10.2) than for benign nodes (mean, 2.95; P < .001). The area under the receiver operating characteristic curve for E-ratio in predicting malignant and benign lymph nodes was 0.816 (95% CI: 0.733-0.899). Our results showed a significant association between tissue elasticity and pathological correlation.

Prediction of Strength Properties of Reinforced and Stabilized Sandy Soil as a Building Foundation Material

Sandy soils are a type of geomaterial that may require improvements due to lack of cohesion. In this study, first, the lack of cohesion of sand was resolved using clay, and the soil was stabilized with cement and lime (4% and 3% of the dry weight of materials, respectively) and finally reinforced with recycled tire fibers of 20 to 30 mm in length for improved strength and ductility. Next, 747 samples with different fiber contents at different curing temperatures and ages were prepared and a unconfined compressive strength (UCS) test was carried out. Next, a novel approach employing multivariate nonlinear regression techniques and obtained empirical data was applied to formulate a mathematical model for predicting the UCS and the modulus of elasticity (Es) of the reinforced and stabilized soil. This model can serve as a valuable tool for building engineers in designing building foundations. The comparison of the obtained UCS and Es results and those predicted using the proposed model showed a correlation of &gt;95% (R2 ≥ 0.95). The fibers effectively increased the failure strain, thus resulting in the greater ductility of the samples. As an example, in 14-day samples cured at 60 °C with 0%, 0.4%, 1%, 1.7%, and 2.5% fibers, the failure strain showed an incremental trend of 1.47%, 1.87%, 2.08%, 2.20%, and 2.92%, respectively. Scanning electron microscopy (SEM) was used to study the microstructure of the samples and to explain the strength experimental outcomes. SEM images showed a desirable interaction between the fiber surfaces with the soil mass and the reduction in porosity and the occurrence of pozzolanic reactions through stabilization. The results also showed that the reinforcement effectively improved the ductility, as desired for building foundations; however, it resulted in reduced strength, although a greater strength compared to the untreated soil was achieved. Although soil stabilization has been widely studied, limited research focuses on stabilizing soil with clay, lime, cement, and recycled tire fibers. This study offers design engineers an estimation scheme of the strength properties of stabilized and reinforced foundations.

Cellulose-enhanced MoS2 bifunctional hydrogel for efficient methylene blue degradation, human body sensing, and recyclability.

In this study, the dispersion behavior of MoS₂ in ionic liquids (ILs) with varying alkyl chain lengths was the primary focus of investigation, followed by the design of a novel PAM/SMA/CMC/PDA@MoS2 hydrogel. By optimizing the concentrations of CMC and PDA@MoS2, a bifunctional hydrogel with both sensing and catalytic functions was successfully developed. Mechanical tests revealed that the PAM/SMA/CMC0.06/0.09PDA@MoS2 hydrogel exhibited exceptional mechanical properties, with stress (505.24 kPa), strain (2333.34 %), elastic modulus (20.17 kPa), and toughness (3990.97 kJ/m3). Furthermore, the hydrogel demonstrated superior sensing performance, characterized by high sensitivity (GF = 7.67) and a rapid response time (148 ms) across a wide strain range. These properties enable precise monitoring of physiological movements, coupled with long-term cyclic stability, positioning it as a versatile material for sensors and electrodes. Subsequently, in situ stabilized silver nanoparticles (Ag NPs) were used as a template for the catalytic degradation of methylene blue (MB) using discarded human motion monitoring hydrogels. The degradation followed first-order kinetics (k = 0.54 min-1 at 25 °C) with 85 % efficiency sustained over 10 cycles, demonstrating significant stability and recyclability. This strategy integrates sensor recycling with Ag NPs based dye degradation, addressing environmental concerns and highlighting its potential in sustainable applications.

Effective Mechanical Properties of a Composite Material Reinforced by Oil Shale Ash Particles

This study determined the elastic properties of composites and concretes reinforced with oil shale ash (OSA) particles, a byproduct of oil shale combustion in an electric power plant in Estonia (Auvere). Since 2018, OSA has no longer been classified as hazardous waste in the EU, enabling its reuse in sustainable materials. The present research examined the effect of OSA on the elastic properties of epoxy–OSA and concrete–OSA composites. The experimental results show that the elastic modulus of epoxy resin increases with an increase in the ash concentration, while it decreases in concrete with a higher OSA content. Theoretical models, including the rule of mixtures, finite element method (FEM), Mori–Tanaka method, and Halpin–Tsai method, were used to predict these properties numerically. The rule of mixtures and FEM generally overestimated the modulus for epoxy–OSA, whereas the Mori–Tanaka and Halpin–Tsai methods provided closer predictions. For concrete–OSA, the compressive strength tests followed the LVS EN 12390-3:2019 standards, with elastic modulus conversions being made via IS 456:2000 Clause 6.2.3.1, which showed a variable decrease across different strength classes. The findings highlight the potential of OSA as a reinforcing filler in construction materials, promoting environmental sustainability by repurposing industrial waste while offering mechanical benefits.

Design and validation of a minimalist, open-source system for measuring elastic modulus evolution in cementitious materials

ABSTRACT The elastic modulus evolution of cementitious materials since early ages can be experimentally measured with the EMM-ARM (Elastic Modulus Measurement through Ambient Response Method) test. This methodology has been extensively validated, but its original implementation relied on costly proprietary platforms. A minimalist, open-source test system may provide a benchmark that sets minimum requirements and performance to enable the development of tailor-made systems. This work aimed to develop, characterise, and validate such system, composed of data-acquisition hardware and post-processing software. Characterisation results showed the system had a spectral noise floor of 2.1 × 10−8 g2/Hz, an RMS noise of 0.003 g, a sampling frequency variability of ± 0.006%, and an average power consumption of 41.53 mAh. Compared to an original EMM-ARM system, validation results indicated the proposed system had an absolute error lower than 0.3% from 1 day of testing onwards, with a similar coefficient of variation of 1.2%.

Mechanical Properties, Corrosion Damage Evolution Laws, and Durability Deterioration Indicators of High-Performance Concrete Exposed to Saline Soil Environment for 8 Years

Most of the current studies rely on simulated brine corrosion environments and lack long-term investigations into concrete corrosion damage evolution under actual corrosive conditions. In this paper, high-performance concrete (HPC) with various mix ratios is designed in the context of the Qinghai Salt Lake region in China, and the evolution of corrosion damage of HPC with different water–binder ratios (W/B) and different fly ash (FA) admixtures under long-term field exposure conditions is obtained by testing the ultrasonic velocity and strengths of the HPC in the field exposure of the HPC in the Qinghai Salt Lake region. The results show that the corrosion resistance of HPC is related to its water–binder ratio and mineral admixture type and dosage under the exposure of 8 years in Qinghai Salt Lake area. HPC with a fly ash dosage of 15–35% and silica fume dosage of 10% exhibits better corrosion resistance when the water–binder ratio (W/B) is between 0.24 and 0.38. The dependence relationship between the corrosion resistance coefficient of HPC and the relative dynamic elastic modulus (Erd) and 28 d standard maintenance strength was also established. The Erd of HPC with a corrosion resistance coefficient of 0.80 or above was 0.73–0.93, not 0.60, which provides an important experimental basis for determining the corrosion damage index of HPC in the high-saline brine environment of the salt lake.

Dynamic structural characteristics and vibration susceptibility of Tongren loess under the influence of water content and confining pressure

Loess is extensively developed on both sides of the Longwu River, a tributary of the Yellow River, Tongren County, Qinghai Province. The engineering geological characteristics are complex, and landslide disasters are highly developed. Based on field geological surveys and physical property analysis of the loess in this area, this study analyzes the influence of water content, consolidation pressure, and soil disturbance on the dynamic characteristics of loess using GDS dynamic triaxial tests. The results show that Tongren loess has strong structural properties. Its dynamic constitutive relationship conforms to the Hardin-Dinevich hyperbolic model, where the parameters a and b decrease with increasing confining pressure and increase with increasing water content. The dynamic cohesion and dynamic friction angle both decrease with increasing water content, with the dynamic cohesion significantly affected, decreasing by 77% ~ 83% when saturated. However, the dynamic friction angle is less affected by water content changes, decreasing by 18% ~ 25% when saturated. Under dynamic conditions, the dynamic friction angle of Tongren loess is only 12 ~ 16°, making slopes composed of Tongren loess highly susceptible to instability and sliding under strong earthquake conditions. The dynamic structural properties of Tongren loess are significantly influenced by water content, with increasing water content destroying the joint structural strength of intact loess. Before reaching the plastic limit water content, the joint structural strength of intact loess decreases sharply with increasing water content, and then decreases slowly. The frictional structural strength shows an opposite trend. Under the same experimental conditions, the failure dynamic stress, maximum dynamic elastic modulus, and dynamic shear strength parameters of intact loess are generally greater than those of remolded loess, and the differences between them decrease with increasing water content. This study provides insights into the dynamic structural characteristics of Tongren loess, which can serve as a reference for understanding the formation mechanisms, stability analysis, and seismic design of loess landslides in the region.

Improving the Mechanical, Corrosion Resistance, Microstructural and Environmental Performance of Recycled Aggregate Concrete Using Ceramic Waste Powder as an Alternative to Cement

This study investigates the effectiveness of replacing the cement with 0, 5, 10, 15, and 20 wt.% of ceramic waste powder (HCCP) to improve the performance of recycled aggregate concrete (RCA) prepared using 25 wt.% wall tile ceramic coarse aggregates. The slump, initial and final setting time, compressive strength, splitting tensile strength, flexural strength, electrical resistivity, bulk density, porosity, total and surface water absorption, pH level, ultrasonic pulse velocity, dynamic elastic modulus, chloride ion diffusion coefficient, chloride penetration depth, microstructure analysis, and environmental assessment properties were investigated. The results showed that replacing cement with HCCP by 5 to 20 wt.% prolonged the setting time and improved all hardened properties. The highest improvements in mechanical properties were observed at 5 wt.% HCCP, with increasing rates of 26.5%, 22%, and 22.4% at 90 days for compressive strength, tensile strength, and flexural strength, respectively. On the other hand, the optimum enhancement for the durability, microstructural, and environmental efficiency properties was recorded at a 20 wt.% HCCP replacement rate. However, the strength at this ratio tended to decrease but remained higher than that of the control RAC. For instance, the total water absorption, surface water absorption, void ratio, chloride penetration depth, and migration coefficient were reduced by 47%, 45%, 38%, 62.3%, and 55.52%, respectively, compared to the reference sample.

A New Type of CuNi/TiB2 Thin-Film Thermocouple Fabricated by Magnetron Sputtering

A new CuNi/TiB2 thin-film thermocouple was fabricated using magnetron sputtering. A 400 nm thick CuNi interior layer was deposited on a dielectric substrate initiatory, and then covered by an 800 nm thick TiB2 layer. The tests revealed that the TiB2 layer had a dense and columnar cross-section. The measured hardness and elastic modulus of the TiB2 layer were ~20.5 and 315.9 GPa, respectively. No cracking or delamination occurred at the CuNi/TiB2 interface. The work functions of the TiB2 and the CuNi layers were calculated to be 4.406 and 4.726 eV, respectively. The difference in work functions between the TiB2 and the CuNi was ~0.3 eV. The CuNi/TiB2 thin-film sensor exhibited a high Seebeck coefficient of 38.07 μV/°C with excellent linearity. The maximum service temperature of the thin-film sensor was evaluated to be ~400 °C. A further increase in temperature degraded the Seebeck coefficient due to oxidation of the TiB2 layer.

Mechanical Properties and Energy Evolution Laws of Rocks Under Freeze–Thaw

In high-altitude mountainous areas, the phenomenon of rock frost damage under repeated freeze–thaw cycles are pronounced, with the deformation and failure processes of rock often accompanied by energy dissipation. To elucidate the energy evolution mechanism of rocks under freeze–thaw cycles, triaxial compression tests and numerical simulation tests were conducted under different freeze–thaw cycles. Results from indoor tests indicate that successive freeze–thaw cycles deteriorate the mechanical properties of rocks. Compared to conditions without freeze–thaw cycles, after 40 freeze–thaw cycles, the peak stress of the rock decreased by 42.8%, the elastic modulus decreased by 64%, and, with increasing confining pressure, the rate of decrease lessened, indicating that confining pressure can inhibit the decline in the mechanical properties of rocks. As the freeze–thaw cycles increase, the total absorption energy (TAE) of rocks gradually decreases. Meanwhile, with increasing confining pressure, the TAE, elastic strain energy (ESE) and dissipated energy (DE) of rocks all gradually increase. However, as the confining pressure increases, the TAE increases by 781%, the ESE increases by 449%, and the DE increases by 6381%. Numerical simulation results reveal that with an increase in the freeze–thaw cycles, shear failure phenomena gradually decrease while tensile failure phenomena gradually increase. During the compression process, the evolution of internal cracks in rocks demonstrates a trend of slow–steady–rapid development, with the number of cracks produced being positively correlated with the freeze–thaw cycles. The performance can provide valuable insights into the degradation mechanism of the mechanical properties of rocks and failure analysis in high-altitude mountainous areas.

Study on Dynamic Response of Damping Type Composite Floor Slabs Considering Interlayer Interaction Influences

In order to explore the vibration mechanism of vibration damping composite floor slabs and further enrich the theory of floor slab vibration calculation, the free vibration characteristics of vibration damped composite floor slabs and the dynamic response of vibration damped composite floor slabs under multi-source excitation is analyzed using first type Chebyshev polynomials to construct the displacement function and derive an analytical solution. The three-dimensional laminated theory is employed, considering the interlayer interaction. Based on the proposed method, the influences of loading types, positions, magnitudes, and frequencies on the vertical vibration of floor slabs are calculated. The study illustrates that, under the action of multi-source excitation, the displacement and acceleration responses calculated by the method proposed in this paper are always greater than those calculated by the single-plate theoretical solution. The dynamic responses of the vibration damping composite floor slab decrease with the increase of the thickness and elastic modulus of the vibration damping layer. Under different thicknesses of the vibration damping layer, the peak accelerations of the vibration damping composite floor slabs increase linearly with the growth of the load amplitude. In addition, the load movement path has a significant effect on the vibration response of the floor slab. When the moving load moves along the short side of the floor, the displacement response of the floor is generally greater than that along the long side of the floor.

Offshore Submerged Aquaculture Flow-Net Interaction Simulation: A Numerical Approach for the Hydrodynamic Characteristics of Nets Produced from Different Materials

The mechanical and hydrodynamic characteristics of single-piece nets are key to the design and optimization of offshore aquaculture net cages. A numerical approach for offshore submerged aquaculture net materials based on the Morison equations and finite element is proposed, simulating the hydrodynamic characteristics of single-piece nets under varying parameters such as wire diameter, mesh size, and flow velocity, and simulating the impact of marine organism attachment on nets by modifying the drag coefficient. The simulation results of nets made from materials such as Copper–Zinc Alloy (Cu-Zn), Zinc–Aluminum Alloy (Zn-Al), Semi-Rigid Polyethylene Terephthalate (PET), and Ultra-High Molecular Weight Polyethylene (UHMWPE) are compared, which provides a theoretical basis for optimizing design parameters and selecting materials for nets based on force conditions and hydrodynamic characteristics. The simulation results indicate that the current force on the net is positively correlated with flow velocity; the maximum displacement of the net is also positively correlated with the flow rate. Compared to other materials, the Cu-Zn net is subjected to the greatest water flow force, while the UHMWPE net experiences the greatest displacement; the larger the diameter of the netting twine, the greater the current force on the net; the mesh size is inversely related to the current force on the net. With increasing drag coefficient, both the maximum displacement of the net and the current force experiences increase, and UHMWPE material nets are more sensitive to increases in the drag coefficient, which indicates a greater impact from the attachment of marine organisms. The density and elastic modulus of the netting material affect the rate of increase in force on the net. The research results can provide a basis for further research on material selection and design of deep-sea aquaculture nets.

Machine Learning-Based Model for Prediction of Elastic Modulus of Calcium Hydroxide in Oil Well Cement Under High-Temperature High-Pressure Conditions

The purpose of this study is to analyze the relationship between the key factors and the output results, and to determine the feasible prediction method of the elastic modulus of calcium hydroxide in oil well cement. Combining the first-principles calculation method with machine learning, Material Studio (MS) was used to simulate calcium hydroxide at different temperatures and pressures, obtain the microstructure parameters of the mechanical properties of calcium hydroxide, and construct the initial data set. At the same time, the random forest feature importance analysis method is used to screen the input parameters, remove the weak correlation variables, and reduce the complexity of the prediction model. On this basis, three prediction models, the BP neural network (BP), radial product function neural network (RBF), and random forest model (RF), are constructed. The hidden layer of the prediction model was adjusted by orthogonal test. The results of different performance evaluation methods are compared, the regression ability of each model is evaluated comprehensively, and the optimal algorithm model is selected. The results show that the determination coefficient of the RBF model is 0.9988, the root mean square error is 0.04331, the average absolute error is 0.02995, the mean square error is 0.01876, and the prediction ability is the best. This method can be used to predict the elastic modulus of calcium hydroxide and provide a reliable method for predicting the elastic modulus of each phase of oil well cement.

Ballistic and Electromagnetic Shielding Properties of Epoxy Resin Reinforced with Carbon Black and Jute Fabric

This study explores the development of a multifunctional composite material by incorporating carbon black (CB) into an epoxy matrix reinforced with 30 vol.% jute fabric. The objective was to evaluate the impact of CB on the composite’s tensile properties, ballistic performance, and electromagnetic shielding effectiveness (SE) within the X-band frequency range (8.2–12.4 GHz). The epoxy composite with 30 vol.% jute and 5 vol.% CB (EJ30/CB5) exhibited 15% improvements in its tensile strength and elastic modulus compared to the epoxy composite with 30 vol.% jute (EJ30) only. Ballistics tests indicated no significant increases in absorbed energy or limit velocity, which may be attributed to the structural rigidity introduced by the CB. An electromagnetic shielding analysis revealed that the CB addition significantly enhanced the SE from ~2 dB in neat epoxy to 5–8 dB in EJ30/CB5, with absorption emerging as the primary shielding mechanism. The findings highlight the potential of CB- and jute-reinforced epoxy composites for applications requiring both mechanical robustness and electromagnetic interference shielding.

Strong and tough polyvinyl alcohol hydrogels with high intrinsic thermal conductivity

Although polyvinyl alcohol (PVA) hydrogels display huge potential in tissue engineering, flexible and wearable electronic devices and soft robotics, their low intrinsic thermal conductivity and weak mechanical properties severely limit their wider applications in these areas. Herein, a Hofmeister effect-assisted “directional freezing-stretching” tactic is employed for simultaneously enhancing the intrinsic thermal conduction and mechanical properties of PVA hydrogels. The hydrogels are obtained through directional freezing followed by salting-out treatment and subsequent mechanical stretching and salting-out (DFS). The DFS PVA hydrogel with 15 wt% of PVA and a stretching ratio of 4 (DFS4) exhibits the highest thermal conductivity of 1.25 W/(m·K), which is 2.4 and 2.8 times that of PVA hydrogel prepared through frozen-thawed (FT) [0.52 W/(m·K)] and frozen-salted out (FS) [0.45 W/(m·K)] methods, respectively. The DFS4 PVA hydrogel also possesses greatly improved mechanical performances, exhibiting an elongation at break of 163.1%. In addition, the tensile strength, toughness, and elastic modulus of DFS4 PVA hydrogel significantly increase to 27.1 MPa, 25.3 MJ·m-3, and 21.5 MPa from 0.4 MPa, 0.32 MJ·m-3, and 0.07 MPa for FT PVA hydrogels, respectively. It is elucidated that the salting-out effect generates hydrophobic and crystalline regions, while directional freezing and stretching enhance the chain orientation in the DFS strategy. These effects synergistically contribute to the improvement of thermal conductivity and mechanical properties of PVA hydrogels.

An analytical model for the in-plane elastic shear modulus of plain-woven fabric composites and its application and experimental validation

In this paper, a new analytical model is proposed that employs experimental data as input to predict the in-plane shear modulus of plain-woven fabric composites. This model boasts high efficiency and rapid computation. Initially, the composite yarn is considered as an idealized curved beam, with its undulation path described by an arc curve and its cross-section simplified into a lenticular shape. Subsequently, a force analysis of the yarn segment is conducted, and the results of the analytical model are derived using the minimum potential energy principle and Castigliano’s second theorem. The input parameters for the analytical model are obtained through thermal ablation experiments and microscopic observations, with T300/Cycom970 plain-woven fabric composites selected as the experimental subject. In addition, tensile tests on ±45° laminates are conducted to validate the effectiveness of the analytical model. The results demonstrate a minimal deviation of −4.15% between the experimental outcomes and the predictions of the analytical model, thereby verifying the model’s validity and the accuracy of the experimental parameters. Leveraging the validated model, the study investigates the influence of crimp ratio and fiber volume fraction on the in-plane shear modulus. Furthermore, to enhance the applicability of the model, a simplified improvement scheme that incorporates temperature and humidity considerations is proposed. This model not only effectively addresses the mechanical property analysis challenges of plain-woven fabric composites, but also provides valuable references for parameter estimation, model construction and experimental design of other woven composite materials.

Comparative study on properties of different fibers (unmodified/modified) reinforced polylactic acid degradable composites under ultraviolet aging conditions

AbstractLaser printing waste paper fibers (LPWF) are classified as high‐quality secondary fibers, characterized by their lightweight nature, high modulus of elasticity, and excellent fiber quality. These attributes present significant opportunities for their application in plant fiber/resin matrix composites. However, the deinking process for LPWF is more challenging compared to traditional waste paper. The conventional recycled paper manufacturing sector often operates with lower value‐added processes, highlighting the urgent need for the industry to achieve high‐value utilization of laser printing waste paper. In this study, we utilized environmentally friendly and abundant sources of LPWF, alongside the biodegradable resin polylactic acid (PLA), as raw materials. LPWF/PLA composites were prepared through melt blending and injection molding techniques, and their performance was compared to other composites made from natural plant fibers (such as wood and straw) in ultraviolet‐accelerated aging experiments. The results demonstrated that the LPWF/PLA composites exhibited superior overall performance after ultraviolet exposure. To enhance the ultraviolet aging resistance of the LPWF/PLA composites, we modified them with dodecenyl succinic anhydride (DDSA) and the ultraviolet absorber UV‐531 combined with silicon dioxide (SiO2). Our findings indicated that the incorporation of these modifiers effectively protected the surface color of the composites, mitigated the degradation of mechanical properties and overall quality, and significantly reduced the occurrence of surface cracks. Notably, the modification using UV‐531/SiO2 yielded the most pronounced protective effects.Highlights Comparison of the properties of three composites before and after UV aging. LPWF have a low lignin content and exhibit outstanding resistance to UV aging. Exploring the ultraviolet aging mechanism of plant fiber/resin composites. Two modifiers were used to modify LPWF/PLA composites. Providing new insights for extending the life of plant fiber‐resin composites.

Investigating the effect of fiber arrangement on tensile properties of two-dimensional hybrid braided composite rods

Braided composites are gaining attention in the most industrial applications. To design rods with optimal tensile properties against combined loads, experimental studies were conducted to investigate the effect of using axial yarn and core in different categories on the tensile properties of braided reinforced composite rods. In this study, six types of braided composite rods with different arrangements of braid components (axial yarn or core type) were produced using glass and polyester fibers with epoxy resin as the matrix. The elastic modulus, ultimate tensile strength, and work of fracture of these rods were tested, and the experimental elastic modulus of samples were compared with previously developed models. Moreover, comparing the stress-strain results of the samples revealed that the produced hybrid samples demonstrate pseudo-ductile tensile behavior, showing varying trends as the type of reinforcement is altered. The results indicate that using a double-layer triaxial braid as reinforcement for the composite can increase the elastic modulus up to 13% compared to the similar single-layer sample. Additionally, employing a double-layer triaxial braid as reinforcement for the composite leads to a greater work of fracture. However, in terms of ultimate tensile strength, biaxial braid reinforcement demonstrates better performance in reinforcing the composite rods.

Microwave Thermal Treatment on Enhanced Cemented Tailings Backfill: An Experimental Study

Cemented tailings backfill (CTB), composed of tailings, binder, and water, is widely used for filling underground goaves in mining operations. Unmanaged tailings can occupy extensive land and pose significant environmental risks. Microwave technology offers a promising approach to enhance the utilization of tailings, reducing dependency on natural resources. However, limited research on microwave heating parameters has impeded its broader adoption. This study uses the orthogonal experimental method to study the influence of various factors on the strength of the CTB and to determine the impact capacity of each factor. Additionally, this study conducted a visual analysis of the microwave heating time (MHT), microwave delay time (MDT), cement-tailings ratio, slurry concentration and microwave power (MP) to verify the experimental results. The results show that microwave heating can enhance or diminish the mechanical properties of CTB samples at different curing ages, depending on the specific microwave parameter settings. Research indicates that microwave technology can be effectively applied to mine backfill materials to improve their early strength and the modulus of elasticity.

Application of J-Integral to a Random Elastic Medium

Abstract This study investigates the use of the J-integral to compute the statistics of the energy release rate of a random elastic medium. The spatial variability of the elastic modulus is modeled as a homogeneous lognormal random field. Within the framework of Monte Carlo simulation, a modified contour integral is applied to evaluate the first and second statistical moments of the energy release rate. These results are compared with the energy release rate calculated from the potential energy function. The comparison shows that, if the random field of elastic modulus is homogenous in space, the path independence of the classical J-integral remains valid for calculating the mean energy release rate. However, this path independence does not extend to the higher order statistical moments. The simulation further reveals the effect of the correlation length of the spatially varying elastic modulus on the energy release rate of the specimen.