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Cervical remodeling is critical for a healthy pregnancy. Premature tissue changes can lead to preterm birth (PTB), and the absence of remodeling can lead to post-term birth, causing significant morbidity. Comprehensive characterization of cervical material properties is necessary to uncover the mechanisms behind abnormal cervical softening. Quantifying cervical material properties during gestation is challenging in humans. Thus, a nonhuman primate (NHP) model is employed for this study. In this study, cervical tissue samples were collected from Rhesus macaques before pregnancy and at three gestational time points. Indentation and tension mechanical tests were conducted, coupled with digital image correlation (DIC), constitutive material modeling, and inverse finite element analysis (IFEA) to characterize the equilibrium material response of the macaque cervix during pregnancy. Results show, as gestation progresses: (1) the cervical fiber network becomes more extensible (nonpregnant versus pregnant locking stretch: 2.03 ± 1.09 versus 2.99 ± 1.39) and less stiff (nonpregnant versus pregnant initial stiffness: 272 ± 252 kPa versus 43 ± 43 kPa); (2) the ground substance compressibility does not change much (nonpregnant versus pregnant bulk modulus: 1.37 ± 0.82 kPa versus 2.81 ± 2.81 kPa); (3) fiber network dispersion increases, moving from aligned to randomly oriented (nonpregnant versus pregnant concentration coefficient: 1.03 ± 0.46 versus 0.50 ± 0.20); and (4) the largest change in fiber stiffness and dispersion happen during the second trimester. These results, for the first time, reveal the remodeling process of a nonhuman primate cervix and its distinct regimes throughout the entire pregnancy. [ABSTRACT FROM AUTHOR]

Sandwich panel composites have a wide range of uses in material technology applications. The designed sandwich panel composite material; is made of stainless steel-316 as the top and bottom plate, aluminum 1050A-0 as the core material, and DP-8405 acrylic adhesive as the binding element. Three-point bending tests and finite element models investigated the bending behavior of S-core composite sandwich panels. Finite element models have been developed to characterize the effect of the bending behavior of composite elements on variations. The specific flexural modulus and strength of composite S-core sandwich structures can be compared with core structures in the literature. Accordingly, the minimum weight design provided a guideline for obtaining weight and density-efficient hybrid composite sandwich panels. When the damage loads in the test results were examined, it was concluded that the damage loads increased between 6.54% and 34.81% as the core thicknesses increased, and the damage loads decreased between 3.65% and 31.46% as the radius of curvature increased. [ABSTRACT FROM AUTHOR]

Fully annealed Zr60700 alloy plates with a thickness of 15 mm were rolled at 15%, 30%, 45%, 60%, and 75% thickness reductions, and the rolling paths were unidirectional rolling (UR) and cross-rolling (CR), respectively. Electron back-scatter diffraction (EBSD) experiments revealed that the texture developed gradually towards the basal texture with increased thickness reduction. Severe orientation hardening enhanced the deformation resistance of the CR sample, resulting in a higher grain size than the UR sample. The plastic deformation during the rolling process was dominated by dislocation slip. The results of the prediction based on the Schmid factor (SF) and the calculation based on the in-grain misorientation axis (IGMA) showed that the prismatic slip was the primary deformation mode in the early stages of the UR and CR processes. With the increase in thickness reduction, the basal and pyramidal slip played an increasingly important role. Compared with the UR process, the CR process was more accessible to activate the basal slip and more conducive to forming the basal texture. Mechanical tests showed that the CR samples exhibited higher isotropy than the as-received and UR samples.

Abstract To study borehole deformation under non-uniform horizontal principal stress in the deep strata, a prediction method for horizontal principal stress was developed based on the morphological parameters of boreholes, the deformation trajectory equation for the standard circular borehole was derived based on elasticity theory, and the morphological characteristics of boreholes were analyzed. Additionally, a quantitative relationship between the geometric parameters of elliptical boreholes and horizontal principal stress was established. Subsequently, uniaxial tests on borehole deformation were conducted to verify elliptical deformation under non-uniform horizontal principal stress. A combined deductive, experimental, and numerical simulation approach to borehole deformation analysis was adopted, and the impact factors of borehole deformation were obtained. The results indicated as following: (1) the deformation morphology of borehole under non-uniform horizontal principal stress was elliptical; (2) for the given lithology, the greater the difference in horizontal principal stress, the greater were the ellipticity and elliptical deformation of borehole; (3) for given stress background, rock strength was inversely proportional to ellipticity. Additionally, the smaller the Young’s modulus and compressive strength, the larger was the Poisson’s ratio and the larger was the ellipticity. For example, the ellipticity of mudstone and coal was greater than that of limestone and sandstone; (4) with an increase in load, the displacement of borehole wall exhibited three stages: initial micro-deformation, accelerated deformation, and stable deformation; (5) horizontal principal stress can be calculated by using the morphological parameters (long and short axes) of an elliptical hole. Furthermore, a horizontal principal stress method theory can be developed based on the morphological parameters of boreholes. The results of our study can provide new ideas and methods for the measurement of in situ stress in deep boreholes and a theoretical basis for the development of equipment for measuring elliptical boreholes.

The growing need for materials that are eco-friendly and sustainable in the industrial sector has shifted focus from synthetic fossil to natural fibers, alongside the utilization of recycled polymer textiles. This research introduces a novel method for using end-of-life textiles, such as polyester and polyamide fabrics, in the production of composite materials, aiming to lessen textile waste and enhance material longevity. The mechanical attributes of flax fabric (FF), flax–recycled polyamide fabric (F/RPA), and flax–recycled polyester fabric (F/RPES) composite laminates are assessed through tensile, flexural, interlaminar shear, and Charpy impact tests. The study revealed that the addition of end-of-life synthetic fibers improves tensile strength, while the trend in modulus values suggests that flax provides a high degree of stiffness to the composites, which is moderated by the addition of synthetic fibers. This effect is consistent across both tensile and flexural testing, although the impact on stiffness is more significant in bending. The inclusion of polyester fibers in the composite laminate resulted in significant enhancements, with an 11.1% increase in interlaminar shear maximum force, a 17.4% improvement in interlaminar shear strength, and a 67.1% rise in un-notch impact energy, compared to composites made with only flax fiber (FF). The microscopic examination uncovered the internal structure and demonstrated a clear, strong bond between the polyester and polyamide fiber layers with the flax fibers. Additionally, the life cycle assessment revealed that the F/RPES composite had less environmental impact than FF and F/RPA in all 18 categories analyzed. This indicates that the environmental footprint of producing F/RPES is smaller than that of both FF and F/RPA. [ABSTRACT FROM AUTHOR]

Bio-polybutylene succinate (PBS) is a biodegradable polymer obtained from renewable feedstock having physical–mechanical properties like traditional low-density polyethylene (LDPE). PBS is employed by many manufacturing sectors, from biomedical to agri-food and cosmetics. Although some studies have already evaluated the resistance of PBS to photodegradation caused by natural outdoor solar exposure (UVA-UVB), a systematic study on the resistance to degradation caused by exposure to UVC rays, which is the subject of this study, has not yet been carried out. PBS was exposed to UVC either neat or filled with 2% carbon black (CB). Mechanical and physical characterization (tensile, hardness, calorimetry, contact angle, morphology, and surface roughness analyses) indicates that the bulk and surface properties of the polymer matrix changes after exposure to UVC radiations, due to a severe degradation. However, the presence of carbon black compensates for the degradation phenomenon. Because UVC rays are used for the sterilization process, necessary in applications such as biomedical, cosmetic, pharmaceutical, food, and other products, a comparison of the protocol used in this paper with the literature's data has been reported and discussed. [ABSTRACT FROM AUTHOR]

The use of biodegradable polymers as matrices in composites gives a wide range of applications, especially in niche areas. The assessment of the effect of the filler content on the change of mechanical properties makes it possible to optimize the composition for specific needs. Biochar was used as a filler in the studied composites with two different biodegradable blends as a matrix. Poly(1,4-butylene adipate-co-1,4-butylene terephthalate)/polylactide/biochar (PBAT/PLA/BC) and polylactide/poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]/biochar (PLA/P(3HB-co-4HB)/BC) composites with 0, 10, 15, 20 and 30 wt% of biochar underwent mechanical tests. The test results revealed a change in the properties of the composites related to the filler content. The results of the tensile test showed that increasing the biochar content increased the tensile modulus values by up to 100% for composites with 30 wt% of biochar, compared to unfilled matrices, and decreased the elongation associated with the breaking of PBAT/PLA and PLA/P(3HB-co-4HB) matrix composites. The elongation values at break of PBAT/PLA and PLA/(3HB-co-4HB) composites with 30 wt% biochar were reduced by 50% and 65%, respectively, compared to the unfilled matrices. PLA/P(3HB-co-4HB) matrix composites, in contrast to PBAT/PLA/BC, showed a decrease in tensile strength with the increases in filler content from 35.6 MPa for unfilled matrix to 27.1 MPa for PLA/P(3HB-co-4HB)/BC30 composites. An increase in filler content increased the brittleness of the composites regardless of the matrix used, as determined under the Charpy impact-test. This phenomenon was observed for all tested PLA/P(3HB-co-4HB) composites, for which the impact strength decreased from 4.47 kJ/m2 for the matrix to 1.61 kJ/m2 for the composite containing 30 wt% biochar. PBAT/PLA-based composites with 10 wt% of biochar showed slightly lower impact strength compared to the unfilled matrix, but composites with 30 wt% biochar showed 30% lower impact strength than PBAT/PLA. The complex viscosity value increased with increased filler content. For all composites tested on both polyester matrices, the viscosity decreased with increasing angular frequency. [ABSTRACT FROM AUTHOR]

Cellulose is one of the most widely used and widely available materials on the planet, and it has been used for centuries in a wide range of applications. In this paper, a new source of cellulose delonix regia fruits has been explored for the extraction of cellulose at the micro and nanoscale. Cellulose is isolated from the raw delonix regia fruits by sub-sequential chemical methods such as pulping, bleaching, delignification, and acid hydrolysis. PVA/CMF and PVA/CNF composites are prepared by the solvent casting process with 1, 3, 5, 7, and 9 percentages of filler concentration. Mechanical, thermal, morphological, moisture absorption, and biodegradability properties of pure PVA, PVA/CMF, and PVA/CNF composite at different filler concentrations were evaluated using mechanical testing (tensile, flexural, and impact), TGA-DTG, SEM, moisture absorption test and soil burial test respectively. The SEM results showed that at increased filler content concentrations, signs of agglomeration began to occur, and the overall performance of the resulting composite material degraded due to which filler addition should be limited to less than 7wt%. Tensile, flexural, and impact test results revealed that nano-fillers performed better than micro-fillers, and the best performance is obtained with filler content below 7%. The degradation temperature of composites with filler content improved dramatically, according to TGA and DTG curves, and composites with nano-fillers had greater thermal stability than composites with micro- fillers. The inclusion of filler content reduced the tendency of composite materials to absorb moisture and the resulting composite materials had enough biodegradation rate together with higher lifetime and performance, according to the findings of the biodegradability test and moisture absorption test. [ABSTRACT FROM AUTHOR]

This study examined the mechanical performance of two polyester resins (isophthalic and orthophthalic) used to create e-glass-based laminate composites for the marine industry. The current study performed a static analysis of laminate composites using compressive, impact and hardness tests. Single edge-notched beam (SENB) fracture tests under mode I (i.e. opening mode) were performed on e-glass reinforced orthophthalic polyester laminate composites (S1) and e-glass reinforced isophthalic polyester laminate composites (S2) at cryogenic temperature (−10°C), ambient temperature (25°C) and high temperature (100°C). The interaction between fibres and matrix material was studied using Fourier transform infrared (FTIR) spectroscopy. A scanning electron microscope (SEM) was used to examine the substructure of fractured surface. A water absorption test was also performed on the fabricated samples. FTIR study revealed NH stretching, CH bend, CN stretching, C-O-C and CH-stretching. e-Glass isophthalic polyester composites had higher compressive strength, impact strength, hardness, fracture toughness and fracture energy than orthophthalic polyester laminate composites. The decrease in temperature increased the fracture properties. In both types of laminate composites, as the temperature increased, the fracture toughness and fracture energy decreased. The diffusion and permeability coefficients of isophthalic composites were greater than those of orthophthalic-based composites. The crushed fibre, fibre pull-out, riverline, matrix-fibre delamination and debonding are all evident in the fractured surface SEM micrograph. [ABSTRACT FROM AUTHOR]

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

Abstract Borosilicate glass was developed to enhance the mechanical behavior and smoothness of dental zirconia as an alternative to conventional glaze. This study assessed the mechanical and optical properties of 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) coated with borosilicate glass or a commercial glaze fired for an extended period of time. Disc-shaped 3Y-TZP zirconia specimens (Zpex, Tosoh) were sintered at 1550°C for 2 hours. The specimens were divided into three groups: as-sintered (control, C); commercial glaze (G); and borosilicate glass (SL). The glaze and borosilicate glass were applied over the zirconia and fired for 20 minutes at 950°C and 1200°C, respectively. Biaxial flexural strength, fractography, X-ray diffraction (XRD), roughness (Ra and Rz), fracture toughness (Vickers indentation method), color difference (∆E00), and translucency (TP00) analyses were conducted. The t-test or the one-way ANOVA and Tukey’s tests were used to analyze the data (α = 0.05). Flexural strength data were subjected to the Weibull analysis. The SL group exhibited the highest flexural strength (1025.8 MPa), whereas the C (859.41 MPa) and G (816.0 MPa) groups exhibited similar values. The SL group also had the highest characteristic strength. The fracture origin in all groups was on the zirconia surface. XRD analysis revealed that the specimens from the SL group contained tetragonal, cubic, and monoclinic phases. The SL group presented the lowest surface roughness. Fracture toughness in the SL group was lower than in the C group, but similar to that observed in the G group. The translucency and color differences observed in the G and SL groups were similar. Borosilicate glass enhanced the flexural strength of 3Y-TZP, promoted the smoothest surface, and exhibited optical properties similar to those of the glaze.

Biological durability remains an understudied area of mass timber construction, despite expert warnings on potential moisture and decay issues that may affect building performance. In an effort to bridge the knowledge gap, this article presents experimental data on the performance of fungal-decayed cross laminated timber (CLT) connection assemblies. A total of 560 connection assemblies were made using select CLT species from major global markets. These were mechanically tested following inoculation by two brown rot fungi for a total period of 78 weeks, with the connections periodically harvested after 10, 20, 30, 40, 52, and 78 weeks. The data from the mechanical tests, which included cyclic evaluation using an abbreviated CUREE loading protocol and dowel bearing strength tests performed in accordance with ASTM D5764, are submitted in this repository. The repository also contains information on mass changes to connection assemblies as decay progressed and SAWS model parameters that were calibrated using the raw data generated from the universal testing machine (UTM) during cyclic tests of the connection assemblies. This work is fundamental for accurate assessment of fungal deterioration in mass timber buildings and the data submitted herein could be used by researchers and scientists to model behavior of connections in mass timber buildings, especially in humid and damp regions with high chances of biodeterioration.

Abstract The study discussed the effects of different mineral incorporations and the curing time on the strength of modified magnesium phosphate cement (MPC) mortars through mechanical tests, mathematical model analysis and microstructure characterization. Fly ash (FA), silica fume (SF), and metakaolin (MK), which exhibit excellent durability and bonding properties, were used to modify the MPC. A quantitative relationship was established between the strength of modified MPC mortars and the mineral incorporation and curing time. First, the strength of each mineral-modified MPC mortar cured in air with different mineral incorporations and curing durations was evaluated. The strengths of MPC mortars containing 10% fly ash, 15% silica fume, and 10% metakaolin—which perform best in their incorporations—were compared to analyze the function of the three minerals. To establish the relationship between strength and mineral incorporation and curing time, three mathematical models, linear model, general nonlinear model, and data distribution shape nonlinear model (DDSNM), are commonly used for material property analysis based on statistics. DDSNM best describes the trend of strength change among the three models and the error is small for three minerals. Based on DDSNM, the influence of various minerals on the strength of MPC mortar was quantitatively evaluated by calculating the variable partial derivatives, and verified by scanning electron microscopy and X-ray diffraction. MK performs the best in improving the flexural strength performance of MPC, while SF performs the best in the compressive strength. FA-MPC has low sensitivity to dosage fluctuations and is easy to prepare.

The study discussed the effects of different mineral incorporations and the curing time on the strength of modified magnesium phosphate cement (MPC) mortars through mechanical tests, mathematical model analysis and microstructure characterization. Fly ash (FA), silica fume (SF), and metakaolin (MK), which exhibit excellent durability and bonding properties, were used to modify the MPC. A quantitative relationship was established between the strength of modified MPC mortars and the mineral incorporation and curing time. First, the strength of each mineral-modified MPC mortar cured in air with different mineral incorporations and curing durations was evaluated. The strengths of MPC mortars containing 10% fly ash, 15% silica fume, and 10% metakaolin—which perform best in their incorporations—were compared to analyze the function of the three minerals. To establish the relationship between strength and mineral incorporation and curing time, three mathematical models, linear model, general nonlinear model, and data distribution shape nonlinear model (DDSNM), are commonly used for material property analysis based on statistics. DDSNM best describes the trend of strength change among the three models and the error is small for three minerals. Based on DDSNM, the influence of various minerals on the strength of MPC mortar was quantitatively evaluated by calculating the variable partial derivatives, and verified by scanning electron microscopy and X-ray diffraction. MK performs the best in improving the flexural strength performance of MPC, while SF performs the best in the compressive strength. FA-MPC has low sensitivity to dosage fluctuations and is easy to prepare. [ABSTRACT FROM AUTHOR]

To improve implant stability parameters, including pedicle screw (PS) outer diameter, thread depth, and pitch, by finite element analysis. Insertion and pullout of the PS were simulated by finite element analysis, and the precision of simulation was evaluated by comparison with mechanical tests. Influences of the parameters on the maximum insertion torque and maximum pullout force were analyzed by computational simulations, including single-factor analysis and orthogonal experiments. The simulation results agreed with the mechanical test results. The order of parameters influencing insertion torque and pullout force was outer diameter > pitch > thread depth. When the pilot hole diameter is 0.1 mm larger than the inner diameter of the PS, the calculated Pearson correlation coefficient between the maximum insertion torque and maximum pullout force was r = 0.99. The optimized PS had a maximum insertion torque of 485.16 N·mm and a maximum pullout force of 1726.33 N, 23.9% and 9.1% higher, respectively, than the values of standard screws. The presently used models are feasible for evaluating the implant stability of PSs. The maximum insertion torque and maximum pullout force of PSs are highly correlated and can be improved by increasing the outer diameter and decreasing pitch. Although with the parameters of the PS, pedicle size and bone mineral density are 2 additional factors to consider for better implant stability. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to reduce the influence of temperature deformation of large-size body-mounted radiators on the observation accuracy of space station telescopes and adapt to launch vibration loads, this paper proposes a floating combination stress release mechanism. Firstly, based on the dimensions, operating conditions, and stress directions of the radiator, an "orthogonal + parallel" layout of the radiator stress release mechanism is designed. To verify whether the layout design complies with the fully constrained theory, the layout design model is simplified into a four-point model, including one fixed support, two line-degree-of-freedom release mechanisms, and one plane-degree-of-freedom release mechanism. Degree-of-freedom analysis is conducted, and the statically determinate support goal is successfully achieved. Then, through the layout design of the stress release mechanism, specific modeling designs are carried out for the fixed support, line-degree-of-freedom release mechanisms, and plane-degree-of-freedom release mechanism using three-dimensional modeling software. Finally, the feasibility of the design scheme is verified through finite element simulation and mechanical testing. The results show that under sine and random vibrations, the maximum response amplification factor is 4.2, which meets the design requirement of being less than five. The maximum stress is 192 MPa, which is lower than the material's yield limit. Under the application of an 80 °C temperature difference, the displacement response value of the radiator is 3.28 mm. This value falls within the allowable movement range of the stress release mechanism and meets the design criteria. [ABSTRACT FROM AUTHOR]

A series of static and dynamic mechanical tests were carried out to investigate the mechanical properties of C-Type Group Material (CGM) cementitious grout and the failure law of damage under dynamic loading conditions.On the basis of the tests, the parameters of the Holmquist-Johnson-Cook (HJC) dynamic principal structure model of the material were calibrated and finite element dynamic simulations of the Split Hopkinson Pressure Bar (SHPB) test were carried out based on LS-DYNA software. The test results show that the CGM cementitious grout is mechanically stable and exhibits significant brittleness under uniaxial stress conditions, significant elastoplasticity under loading with surrounding pressure and significant rate effect under dynamic loading conditions, When the strain rate reaches 119 s-1, the dynamic peak strength can be increased by 1.62 times. The numerical simulation results show that the peak stress and peak strain of the CGM cementitious grout before damage at different strain rates can be accurately predicted using the HJC constitutive model parameters calibrated from the test data, which provides a reference for the application of this material under dynamic impact. [ABSTRACT FROM AUTHOR]

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., 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.)

Due to the high interest in the use of glass/epoxy laminates in aerospace applications, aviation, and as cryogenic tanks, it is crucial to understand the behavior of composites under challenging environmental conditions. Polymer composites are exposed to low temperatures, including cryogenic temperatures, which can lead to the initiation of microdamage. This paper investigates damage initiation/accumulation and its influence on the properties of cross-ply woven glass fiber epoxy composites at low temperatures compared to room temperature conditions. To evaluate the influence of a low-temperature environment on the mechanical performance of glass fiber reinforced epoxy composite (GFRP) laminates, three types of test campaigns were carried out: quasi-static tensile tests and stepwise increasing loading/unloading cyclic tensile tests at room temperature and in a low-temperature environment (−50 °C). We demonstrated that the initial stiffness of the laminates increased at low temperatures. On the other hand, there were no observed changes in the type or mechanism of developed damage in the two test conditions. However, the reduction in stiffness due to the accumulated damage was more significant for the laminates tested at low temperatures (~17% vs. ~11%). Exceptions were noted in a few formulations where the extent of damage at low temperatures was insignificant (<1%) compared to that at room temperature. Since some of the studied laminates exhibited a relatively minor decrease in stiffness (~2–3%), we can also conclude that the formulation of matrix material plays an important role in delaying the initiation and formation of damage. [ABSTRACT FROM AUTHOR]

In this study, comprehensive analyses were used to evaluate the physical and chemical properties of basalt fibers, employing a variety of instruments. Additionally, heat treatment and solvent treatment methods were used to eliminate the sizing present on fiber surfaces. The heat treatment process involved determining the optimal temperature and duration required to remove the sizing from the basalt fibers. The appearance, chemical composition, and crystal structure of the original fibers were examined, including those subjected to heat treatment and those treated with solvents. These treated fibers were then incorporated into concrete to create basalt fiber-reinforced concrete (BFRC) specimens for mechanical tests, which assessed their compressive, flexural, and splitting tensile strengths. The results revealed that heat treatment at 300 °C for 180 min effectively removed the sizing on the basalt fibers, and the heat-treated basalt fibers exhibited uniform dispersion inside the BFRC specimens. In addition, solvent treatment primarily removed the soluble components of the sizing. The mechanical properties of specimens with sizing-removed basalt fibers were better than the specimens with original basalt fibers and the benchmark specimens. Crucially, the mechanical test results demonstrated that BFRC incorporating heat-treated basalt fibers exhibited a superior mechanical performance compared to BFRC incorporating original fibers or fibers subjected to the solvent treatment. [ABSTRACT FROM AUTHOR]

This article offers a comprehensive review focused on the analysis and characterization of shale reservoirs, unconventional hydrocarbon resources that uniquely serve as both the source reservoir for gas and oil, and the rock. To analyze and characterize shale reservoirs, pore structure, rock components and rock mechanical properties are three main factors to analyze. These three main factors are necessary for successful field operations in shale reservoirs. Until now, there are various techniques utilized to characterize these three properties. Therefore, this study delves into the intricacies of shale reservoir's pore structure, rock components and mechanical properties under varying geological conditions, summarizing various techniques utilized to characterize these properties in previous studies. The study also discusses the role of analytical techniques in understanding the complex interactions between kerogen and the surrounding mineral matrix. By providing a summary of various techniques operated on the mentioned three main factors, this paper supplies the effective and optimal technique on analyzing different properties of shale reservoirs. Furthermore, the paper aims to contribute to more effective resource assessment and production optimization in shale reservoirs, offering insights that have significant implications for the future of unconventional hydrocarbon extraction.

The effect of the heat treatment and the water absorption of the glass-fiber and recycled cotton fabric-reinforced hybrid composites on the mechanical and physical characteristics were examined in the research. The heat treatment at 80 °C significantly improved G-C-G's tensile as well as flexural strengths by 21% and 28%, respectively. However, due to the improved bonding among the matrix and fiber, G-C-G layer fiber hybrid composites performed better mechanical characteristics than the other alternative composite layers. However, after water absorption, the tensile, and flexural strength of all types of composites diminished from the as-cast samples. In this instance, the flexural and tensile strengths of the G-C-G hybrid composites decreased by 12.87% and 19.11%, respectively, and the bonding between the fiber and matrix degraded was evaluated by SEM images. The maximum amount of water absorption (23.15%) is found for C–C–C composites due to the porosity presented in the cotton fiber. The study evaluated optimal ratios of glass fiber to cotton-reinforced composites, considering both practical and financial aspects. In this case, the G-G-G composites always show better mechanical properties, but the variation among the strength of G-G-G as well as G-C-G is marginal. G-C-G fiber-based hybrid materials are more acceptable because of their affordable cost as well as biodegradable properties than G-G-G composites. Cotton/glass fiber reinforced composites have been proposed as an alternative to appealing elements in the building, automotive, and textile industries.

In this work, carbon-epoxy composites obtained by an autoclave process were subjected to accelerated ageing in controlled conditions of temperature, water and UV radiation. Each composite was exposed to salt water at 60°C or UV radiation at 60°C over a period of 6 months. Changes within the composites were evaluated by mass and density variation, mechanical testing and also in terms of camouflage. Results did not show significant changes in mass loss or density, and it was found that mechanical properties had decreased slightly. The biggest change is in camouflage. It was observed that during accelerated ageing, the composites' reemission coefficient becomes too high and composites lose camouflage properties. [ABSTRACT FROM AUTHOR]

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., 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.)

This research analyses how different cement mortars behave in terms of their physical and mechanical properties. Several components were necessary to make seven mixes of mortars, such as Portland cement, standard sand, and solid waste from a factory of sodium silicate, in addition to graphene oxide. Furthermore, graphene oxide (GO) was selected to reduce the micropores and increase the nanopores in the cement mortar. Hence, some tests were carried out to determine their density, humidity content, water absorption capacity, open void porosity, the alkali–silica reaction, as well as flexural and mechanical strength and acid resistance. Thus, standard-sand-manufactured mortars' mechanical properties were proved to be slightly better than those manufactured with recycled waste; the mortars with this recycled aggregate presented problems of alkali–silica reaction. In addition, GO (in a ratio GO/cement = 0.0003) performed as a filler, improving the mechanical properties (30%), alkali–silica (80%), and acid resistance [ABSTRACT FROM AUTHOR]

The determination of bone mechanical properties remains crucial, especially to feed up numerical models. An original methodology of inverse analysis has been developed to determine the longitudinal elastic modulus of femoral cortical bone. The method is based on a numerical twin of a specific three-point bending test. It has been designed to be reproducible on each test result. In addition, the biofidelity of the geometric acquisition method has been quantified. As the assessment is performed at the scale of a bone shaft segment, the Young's modulus values obtained (between 9518.29 MPa and 14181.15 MPa) are considered average values for the whole tissue, highlighting some intersubject variability. The material microstructure has also been studied through histological analysis, and bone-to-bone comparisons highlighted discrepancies in quadrants microstructures. Furthermore, significant intrasubject variability exists since differences between the bone's medial-lateral and anterior-posterior quadrants have been observed. Thus, the study of microstructures can largely explain the differences between the elastic modulus values obtained. However, a more in-depth study of bone mineral density would also be necessary and would provide some additional information. This study is currently being setup, alongside an investigation of the local variations of the elastic modulus. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) is a versatile technology with potential applications in healthcare and medical instruments, where surface disinfection or sterilization is essential. This study comprehensively the effect of commonly used cost-effective disinfectants, ethanol (70 V/V%) and chlorine solution on the mechanical and thermal properties of flexible 3D printed materials. The following materials were tested before and after a 5-cycle surface disinfection: Flexfill TPE 90A, Phyton Flex (TPU) for material extrusion, Flexible (resin), Elastic 50A (resin) for vat photopolymerization and Flexa Black (TPU) material for powder bed fusion technology. Mechanical tests included tensile, compression, Charpy impact, flex resistance and stress relaxation tests, as well as Shore A hardness and volume measurements. The structure was analyzed using scanning electron microscopy (SEM)and Raman spectroscopy. The cytotoxicity was assessed using a A549 cell viability assay. The results show that after disinfection, significant changes occurred mainly in the tensile and Shore A properties, such as the tensile strength of the disinfected Flexible (resin) materials was 3.44 MPa ± 0.51 MPa (ethanol) and 2.62 MPa ± 0.31 MPa compared to the native 2.02 MPa ± 0.24 MPa. Interestingly, the applied surface disinfectants can negatively affect biocompatibility. Medical devices have been designed and fabricated based on the findings. Our findings can serve as a guide to the potential applications of commonly used 3D printed flexible materials in the biomedical field.

Abstract The fracture of a bronze object is usually accompanied by localized deformation. The deformed part often tends to spring back at an unpredictable moment after its shape is corrected. The reconstruction of the area adjacent to the damage should be sufficiently resistant to the stress derived from springback so that the whole structure can remain stable. However, the choice of gap-filling materials for bronze objects is typically based on personal experience, and there are few available studies on their pertinent properties. The present study focused on a typical situation of deformation, took the flexural modulus as a crucial parameter and explored the development of a protocol for selecting a gap-filling material for bronze restoration in terms of its mechanical property. The flexural modulus was measured for the main classes of materials in use, and the factors related to preparation that influenced performance were studied. Among the various materials tested, carbon fiber reinforced (CFR) materials exhibited an advantageous value of the modulus and notable operational convenience. Further tests were conducted to assess their chemical safety for application in a museum context, as well as their surface workability. After obtaining overall encouraging results, composites reinforced with CF cloth and chopped CF were applied to the reconstruction of different parts of an archaeological bronze vessel. Indications for future improvement in the experimental setup and some practical notes regarding the use of CFR materials were also provided in this paper.

The growing need for materials that are eco-friendly and sustainable in the industrial sector has shifted focus from synthetic fossil to natural fibers, alongside the utilization of recycled polymer textiles. This research introduces a novel method for using end-of-life textiles, such as polyester and polyamide fabrics, in the production of composite materials, aiming to lessen textile waste and enhance material longevity. The mechanical attributes of flax fabric (FF), flax–recycled polyamide fabric (F/RPA), and flax–recycled polyester fabric (F/RPES) composite laminates are assessed through tensile, flexural, interlaminar shear, and Charpy impact tests. The study revealed that the addition of end-of-life synthetic fibers improves tensile strength, while the trend in modulus values suggests that flax provides a high degree of stiffness to the composites, which is moderated by the addition of synthetic fibers. This effect is consistent across both tensile and flexural testing, although the impact on stiffness is more significant in bending. The inclusion of polyester fibers in the composite laminate resulted in significant enhancements, with an 11.1% increase in interlaminar shear maximum force, a 17.4% improvement in interlaminar shear strength, and a 67.1% rise in un-notch impact energy, compared to composites made with only flax fiber (FF). The microscopic examination uncovered the internal structure and demonstrated a clear, strong bond between the polyester and polyamide fiber layers with the flax fibers. Additionally, the life cycle assessment revealed that the F/RPES composite had less environmental impact than FF and F/RPA in all 18 categories analyzed. This indicates that the environmental footprint of producing F/RPES is smaller than that of both FF and F/RPA.

Bio-polybutylene succinate (PBS) is a biodegradable polymer obtained from renewable feedstock having physical–mechanical properties like traditional low-density polyethylene (LDPE). PBS is employed by many manufacturing sectors, from biomedical to agri-food and cosmetics. Although some studies have already evaluated the resistance of PBS to photodegradation caused by natural outdoor solar exposure (UVA-UVB), a systematic study on the resistance to degradation caused by exposure to UVC rays, which is the subject of this study, has not yet been carried out. PBS was exposed to UVC either neat or filled with 2% carbon black (CB). Mechanical and physical characterization (tensile, hardness, calorimetry, contact angle, morphology, and surface roughness analyses) indicates that the bulk and surface properties of the polymer matrix changes after exposure to UVC radiations, due to a severe degradation. However, the presence of carbon black compensates for the degradation phenomenon. Because UVC rays are used for the sterilization process, necessary in applications such as biomedical, cosmetic, pharmaceutical, food, and other products, a comparison of the protocol used in this paper with the literature’s data has been reported and discussed.

The use of biodegradable polymers as matrices in composites gives a wide range of applications, especially in niche areas. The assessment of the effect of the filler content on the change of mechanical properties makes it possible to optimize the composition for specific needs. Biochar was used as a filler in the studied composites with two different biodegradable blends as a matrix. Poly(1,4-butylene adipate-co-1,4-butylene terephthalate)/polylactide/biochar (PBAT/PLA/BC) and polylactide/poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate]/biochar (PLA/P(3HB-co-4HB)/BC) composites with 0, 10, 15, 20 and 30 wt% of biochar underwent mechanical tests. The test results revealed a change in the properties of the composites related to the filler content. The results of the tensile test showed that increasing the biochar content increased the tensile modulus values by up to 100% for composites with 30 wt% of biochar, compared to unfilled matrices, and decreased the elongation associated with the breaking of PBAT/PLA and PLA/P(3HB-co-4HB) matrix composites. The elongation values at break of PBAT/PLA and PLA/(3HB-co-4HB) composites with 30 wt% biochar were reduced by 50% and 65%, respectively, compared to the unfilled matrices. PLA/P(3HB-co-4HB) matrix composites, in contrast to PBAT/PLA/BC, showed a decrease in tensile strength with the increases in filler content from 35.6 MPa for unfilled matrix to 27.1 MPa for PLA/P(3HB-co-4HB)/BC30 composites. An increase in filler content increased the brittleness of the composites regardless of the matrix used, as determined under the Charpy impact-test. This phenomenon was observed for all tested PLA/P(3HB-co-4HB) composites, for which the impact strength decreased from 4.47 kJ/m2 for the matrix to 1.61 kJ/m2 for the composite containing 30 wt% biochar. PBAT/PLA-based composites with 10 wt% of biochar showed slightly lower impact strength compared to the unfilled matrix, but composites with 30 wt% biochar showed 30% lower impact strength than PBAT/PLA. The complex viscosity value increased with increased filler content. For all composites tested on both polyester matrices, the viscosity decreased with increasing angular frequency.

Background: Whether polycystic ovary syndrome (PCOS) affects bone health during a woman's lifespan remains controversial. An androgenized rodent model replicated many metabolic and reproductive features of women with PCOS, and we aimed to use it to investigate the impact of androgens on microarchitecture (by micro-CT), bone mechanical strength, bone formation and resorption markers in rats with intact ovaries (SHAM) who underwent oophorectomy. Methods: Wistar rats (Rattus norvegicus albinus) were employed for the experiments in this study. The protocol of androgenization consisted of the application of 1.25 mg s.c. testosterone propionate beteween days 2–5 of life, while the controls received the same amount of corn oil s.c. as previously established. Androgenized SHAM rats exhibited chronic anovulation identified by vaginal cytology and a reduction in the proportion of corpus luteum in the ovary in comparison to control SHAM rats. The realization of the ovariectomy or SHAM procedure occurred on Day 100 of life. All groups (n = 8) were followed-up for 180 days to address the study endpoints. Results: Micro-CT from androgenized female rats (SHAM) showed a divergence between the trabecular and cortical bone profiles. Compared to SHAM controls, these rats had an increase in trabecular bone mass with a diminution in bone resorption C-terminal telopeptide of type 1 collagen (CTX) (p

The fracture of a bronze object is usually accompanied by localized deformation. The deformed part often tends to spring back at an unpredictable moment after its shape is corrected. The reconstruction of the area adjacent to the damage should be sufficiently resistant to the stress derived from springback so that the whole structure can remain stable. However, the choice of gap-filling materials for bronze objects is typically based on personal experience, and there are few available studies on their pertinent properties. The present study focused on a typical situation of deformation, took the flexural modulus as a crucial parameter and explored the development of a protocol for selecting a gap-filling material for bronze restoration in terms of its mechanical property. The flexural modulus was measured for the main classes of materials in use, and the factors related to preparation that influenced performance were studied. Among the various materials tested, carbon fiber reinforced (CFR) materials exhibited an advantageous value of the modulus and notable operational convenience. Further tests were conducted to assess their chemical safety for application in a museum context, as well as their surface workability. After obtaining overall encouraging results, composites reinforced with CF cloth and chopped CF were applied to the reconstruction of different parts of an archaeological bronze vessel. Indications for future improvement in the experimental setup and some practical notes regarding the use of CFR materials were also provided in this paper. [ABSTRACT FROM AUTHOR]

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Biopolymer-based edible films and coatings are vital in making the global food-packaging industry more sustainable. These films/coatings protect and extend the shelf life of food by acting as barriers to moisture, oxygen, microorganisms, and ultraviolet light. Polysaccharides, due to abundant availability from natural plant-based resources and the tendency to form a gel in water, are excellent low-cost choices for packaging films. Additives such as hydrophobic agents, plasticizers, binders, and antimicrobial agents will improve the properties of films and coatings. The present work aims to develop pectin-based packaging film (from 5% w/v film-forming solution) by adding castor oil as a hydrophobic agent, beeswax as a plasticizer, and clove oil as an antimicrobial agent. Films were developed by using 23 (two-level, three-factor) statistical factorial design experiments. The amount of castor oil (5% and 15%), beeswax (5% and 10%), and clove oil (2% and 4%) are taken as the three factors. The developed films were analyzed for physical, moisture barrier, morphological, thermal, and tensile properties, and resistance to microbial growth. The results indicated that clove oil is a good antimicrobial agent. Furthermore, beeswax had a great impact by enhancing antimicrobial activity, elongation, and moisture barrier properties. Castor oil integration remarkably lowered the moisture and oxygen transmission rates relative to pure pectin films and some other additives reported in the literature. The optimized biofilms had a thickness of ~0.10 ± 0.004 mm, pH = 3, and transparency of ΔΕ = 9.15 to 25. The elongation at break increased at least four times. The films were thermally stable at 400 °C. The detailed statistical analysis and analysis of various studies indicate that the amount of castor oil (p < 0.05), a combined effect of castor oil and beeswax (p < 0.05) is significant on barrier properties while the effect of beeswax (p < 0.05) is also significant on mechanical properties. [ABSTRACT FROM AUTHOR]

In the design and fabrication of any structural system for space application, balance between mass, stiffness and strength is crucial. Structures in space environments are exposed to high radiation levels and thermal shock, due to the sun irradiance and rotation around Earth. Therefore, accurate determination of the thermal and radiation properties is a key issue for the materials used in such applications. This study reports the thermal and mechanical performance of particle composites (epoxy resin and ZnO particles) after gamma and UV radiation. Composites are exposed to gamma and UV radiation at rates of 1 kGy and 10 kGy and characterized after exposure. For the evaluation, DMA, TGA and three-point bending mechanical test are performed to determine thermal properties and possible material degradation after radiation exposure. The incorporation of the filler in the thermal, radiation and mechanical response of the epoxy system improves as a function of its concentration. Then, epoxy resin reinforced with ZnO particles can be a potential candidate as a polymeric matrix for fiber-reinforced composites for nanosatellites.

With the increased emphasis on the use of recyclable bio-based materials and further understanding of the mechanical properties of laminated bamboo, the development of a new generation of low-cost bamboo-based composites for ship structure has generated a significant interest. Laminated bamboo composites comprising Apus bamboo (Gigantochloa apus) and Waru fiber at different layer orientations were investigated to obtain the mechanical characteristics. The influence of different laminate directions was studied through several methods of mechanical testing, including impact tests using ASTM D256, bending tests using ASTM D7264, and tensile tests using ASTM D3039. Results showed that material strength properties could be improved by using on-axis direction (0°). The bamboo composites with unidirectional (0°) laminate direction exhibited superior mechanical properties to bidirectional laminate directions (45°/−45° and 0°/90°). The addition of Waru fiber improved the mechanical properties of the currently developed material; that is, bending strength increased by about 3.17–14.18% and tensile strength was in the range of 4.88–20.28%. Only those composites with 0° and 0°/90° layer orientations fulfilled the Indonesian Bureau Classification strength threshold.

Abstract Background Degenerative disc disease is one of the most common ailments severely affecting the quality of life in elderly population. Cervical intervertebral body fusion devices are utilized to provide stability after surgical intervention for cervical pathology. In this study, we design a biomimetic porous spinal cage, and perform mechanical simulations to study its performances following American Society for Testing and Materials International (ASTM) standards before manufacturing to improve design process and decrease cost and consumption of material. Methods The biomimetic porous Ti-6Al-4 V interbody fusion devices were manufactured by selective laser melting (laser powder bed fusion: LPBF in ISO/ASTM 52900 standard) and subsequently post-processed by using hot isostatic pressing (HIP). Chemical composition, microstructure and the surface morphology were studied. Finite element analysis and in vitro biomechanical test were performed. Findings The post heat treatment can optimize its mechanical properties, as the stiffness of the cage decreases to reduce the stress shielding effect between two instrumented bodies. After the HIP treatment, the ductility and the fatigue performance are substantially improved. The use of HIP post-processing can be a necessity to improve the physical properties of customized additive manufacturing processed implants. Interpretation In conclusion, we have successfully designed a biomimetic porous intervertebral device. HIP post-treatment can improve the bulk material properties, optimize the device with reduced stiffness, decreased stress shielding effect, while still provide appropriate space for bone growth. Clinical significance The biomechanical performance of 3-D printed biomimetic porous intervertebral device can be optimized. The ductility and the fatigue performance were substantially improved, the simultaneously decreased stiffness reduces the stress shielding effect between two instrumented bodies; while the biomimetic porous structures provide appropriate space for bone growth, which is important in the patients with osteoporosis.

In order to reduce the influence of temperature deformation of large-size body-mounted radiators on the observation accuracy of space station telescopes and adapt to launch vibration loads, this paper proposes a floating combination stress release mechanism. Firstly, based on the dimensions, operating conditions, and stress directions of the radiator, an “orthogonal + parallel” layout of the radiator stress release mechanism is designed. To verify whether the layout design complies with the fully constrained theory, the layout design model is simplified into a four-point model, including one fixed support, two line-degree-of-freedom release mechanisms, and one plane-degree-of-freedom release mechanism. Degree-of-freedom analysis is conducted, and the statically determinate support goal is successfully achieved. Then, through the layout design of the stress release mechanism, specific modeling designs are carried out for the fixed support, line-degree-of-freedom release mechanisms, and plane-degree-of-freedom release mechanism using three-dimensional modeling software. Finally, the feasibility of the design scheme is verified through finite element simulation and mechanical testing. The results show that under sine and random vibrations, the maximum response amplification factor is 4.2, which meets the design requirement of being less than five. The maximum stress is 192 MPa, which is lower than the material’s yield limit. Under the application of an 80 °C temperature difference, the displacement response value of the radiator is 3.28 mm. This value falls within the allowable movement range of the stress release mechanism and meets the design criteria.