Mechanical Analysis Research Articles

Experimental evaluation of temporary plugging performance and mechanism analysis of degradable preformed particle gel based on NMR technology

Utilizing chemical temporary plugging systems to further increase the stimulated reservoir volume (SRV) and improve oil recovery (IOR) has become a hot topic in the current petroleum industry. Pre-formed gel particles (PPG) possess excellent swelling properties and can form high-strength plugging in high-permeability channels. In addition, degradable pre-formed gel particles (DPPG) also exhibit self-degradation characteristics and excellent temporary plugging and fluid diverting performance. In our previous studies, we examined the temporary plugging mechanisms of DPPG prepared with different molecular weight (MW) of crosslinking agents (PEGDA) through bottle tests and core displacement experiments. However, the micro-swelling mechanism and the micro-scale temporary plugging mechanism in pore throats of reservoir cores are still unclear. In this paper, comprehensive research was conducted on the micro-temporary plugging mechanism of DPPG prepared with different MW crosslinking agents using a static temporary plugging performance evaluation method based on nuclear magnetic resonance (NMR) technology and a dynamic temporary plugging performance evaluation method in cores. The research results showed that DPPG with different compositions have different micro-swelling mechanisms. NMR-T2 analysis showed that DPPG-M1 (with the smallest MW of crosslinking agent) gradually decreased in nuclear size during the water absorption and swelling process, and had the largest swelling volume and swelling rate. On the other hand, DPPG-M5 (with the largest MW of crosslinking agent) exhibited a slow diffusion process of surface water towards the nucleus, resulting in the smallest swelling volume and swelling rate. However, its complete degradation time was longer. The T2 (i.e., spin-spin relaxation time) variation results of the cores in the dynamic temporary plugging experiment showed that the decrease of the MW of the crosslinking agent enhanced the plugging performance, and with less damage to the formation. The MRI images confirmed that DPPG-M5 had strong injection capability in the core and caused greater damage to the core. The research results of this study showed that NMR technology can reveal the temporary plugging mechanism of DPPG from a micro-level perspective.

Bio-functionalized hydrogel patches of chitosan for the functional recovery of infarcted myocardial tissue

The aim of this work was to assess the potential benefits of the enrichment of a chitosan hydrogel patch with secretome and its epicardial implantation in a murine model of chronic ischemia, focusing on the potential to restore the functional capacity of the heart. Thus, a hydrogel with a final polymer concentration of 3 % was prepared from chitosan with an acetylation degree of 24 % and then bio-functionalized with a secretome produced by mesenchymal stromal cells. The identification of proteins in the secretomes showed the presence of several proteins known to have beneficial effects on cardiac muscle repair. Then chitosan hydrogels were immersed in secretome. The protein incorporation in the hydrogel and their release over time were studied, demonstrating the ability of the gel to retain and then deliver proteins (around 40 % was released in the first 6 h, and then a plateau was reached). Moreover, mechanical analysis exhibited that the patches remained suturable after enrichment. Finally, bio-functionalized hydrogel patches were sutured onto the surface of the infarcted myocardium in rat. Thirty days after, the presence of enriched hydrogels induced a reversion of cardiac function which seems to come mainly from an improvement of left ventricle systolic performance and contractility.

A highly water-soluble phenoxazine quaternary ammonium compound catholyte for pH-neutral aqueous organic redox flow batteries

The pH-neutral aqueous redox flow battery (ARFB) is one of the most attractive flow batteries due to its non-corrosiveness, low-cost, and wider electrochemical stability window compared to those with acidic or alkaline electrolytes. However, there are few families of organic redox-active molecules available as catholyte materials for pH-neutral ARFBs. Herein, through incorporation of quaternary ammonium moiety into the redox-active phenoxazine nucleus, an organic catholyte material, N, N, N-trimethyl-2-(10H-phenoxazin-10-yl) ethan-1-aminium chloride (NEt-POZ) is achieved for pH-neutral ARFBs. The NEt-POZ has a high redox potential of 0.79 V versus SHE and rapid redox kinetics (0.23 cm s−1) as well as high water-solubility (∼2.6 M in H2O). Paired with a methyl viologen (MV) anolyte in the pH-neutral aqueous electrolyte, a viologen-phenoxazine ARFB full cell is assembled, which shows an open circuit voltage of ∼1.23 V. However, the results of long-term cycling experiments indicate low Coulomb efficiency and rapid declining capacity of the NEt-POZ catholyte. The mechanism analysis unveils that the unstable doubly oxidized tri-cations (NEt-POZ3+) formed via the disproportionation of radical di-cations (NEt-POZ2+) in solution readily react with chloride anions to form poly-chlorinated derivatives, which precipitate from the catholyte due to their poor water solubility, leading to a rapid decrease in capacity. When there is no chloride present in the electrolyte solution, highly reactive NEt-POZ3+ cations can interact with other counter-anions (such as sulfate and carbonate ions) and even water to form complex adducts.

Harmonizing Digital Trade for Sustainable Stride: Unveiling the Industrial Pollution Reduction Effect of China's Cross-Border E-Commerce Comprehensive Pilot Zones

As a key export-oriented economy, China faces significant challenges to its green economic development due to industrial pollution. While digital trade is crucial for sustainable development, its impact on industrial pollution has not been studied. This paper addresses this gap by adopting prefecture-level data from 2005 to 2021 and using a staggered difference-in-differences model to assess the impact of comprehensive pilot zones policy of cross-border e-commerce (CBEC) on industrial sulfur dioxide pollution. The findings indicate that CBEC significantly reduces industrial sulfur dioxide emission intensity, with the effect growing stronger over time. The effect is particularly notable in eastern and western regions, large cities, cities with underdeveloped digital infrastructure, and cities with lower pollution. Mechanism analysis reveals that CBEC lowers industrial emission intensity by driving structure upgrading, fostering green innovation, and advancing digital transformation. This paper emphasizes that the government can expedite the green transformation of the economy by integrating digital trade with industry.

Synergistic electro-thermal enhancement of nitrogen removal in an iron-based Anammox system at low temperatures

In this study, a novel AC-stimulation technology was explored by synergistic electro-thermal enhancement for nitrogen removal in a Fe-based Anammox at low temperatures. Highest total nitrogen (TN) removal efficiency achieved by the AC-stimulated Anammox system was 73.59 % at 0.45 mA/cm2 AC densities, compared to 45.72 % TN removal efficiency realized in the control (non-AC-stimulated) Anammox system, both conducted at 13 °C. Additionally, the Anammox enzymes HZS and HDH exhibited the highest copy numbers at the same current density. Results from response surface methodology (RSM) analysis indicated that the optimal conditions included electrode spacings of 3.89 cm, 4.11 cm, and 3.78 cm, and AC densities of 0.43 mA/cm2, 0.46 mA/cm2, and 0.39 mA/cm2 at temperatures of 13 °C, 16 °C, and 19 °C, respectively. Mechanism analysis revealed that the electrons provided by AC could stimulate biological processes while simultaneously heating the material.

Does advanced human capital structure improve carbon emission performance in China? Empirical research from a spatial spillover perspective

Facilitating coordination between economic growth and carbon mitigation is vital for the sustainability of human society. Identifying the driving factors of Carbon emission performance (CEP) is crucial for its improvement. Nevertheless, empirical research on the relationship between advanced human capital structure (AHCS) and CEP remains scarce. This study analyzes the impact of AHCS on CEP utilizing a dataset covering 30 Chinese provinces from 2006 to 2021. First, we construct a global epsilon-based measure (EBM) model with undesired output to accurately measure the multi-period CEP for Chinese provinces. Next, we evaluate the level of AHCS from the perspective of dynamic evolution. Subsequently, a spatial Durbin model (SDM) is employed to examine the spatial spillover effects of AHCS on CEP. The results illustrate that CEP exhibits significant positive spatial spillover effects across provinces. Additionally, AHCS has a direct and significant positive impact on local CEP and can indirectly enhance CEP in neighboring regions through spillover effects, although the impact varies across different regions. The impact mechanism analysis indicates that AHCS enhances CEP via technological advancement, industrial structure upgrading (ISU), and energy efficiency improvement, despite the asymmetric effects observed between local and neighboring provinces. Therefore, shaping a favorable educational environment to optimize the human capital structure is critical for the improvement of CEP. In addition, promoting resource sharing and technology exchange through regional cooperation is essential for China’s low-carbon transition development.

Environmental protection tax policy and corporate risk-taking: Evidence from China

The fight against pollution problems has sparked a myriad of Environmental Protection Tax (EPT) policies by governments across the globe. However, it remains unclear whether and how EPT affects the level of corporate risk-taking. To narrow the gap, this research selects the EPT policy implemented in 2018 as a quasi-natural experiment to test the effect of EPT on the level of corporate risk-taking by using the sample of Chinese listed firms from 2014 to 2022. The result finds that EPT could dampen the level of corporate risk-taking. Mechanism analysis shows that, the increased market attention, elevated financing costs, and raised investment in end-of-pipe pollution control are the mechanisms by which EPT reduces the level of corporate risk-taking. The “market pressure hypothesis” and “resource dependence hypothesis” of corporate risk-taking can help us better understand these three paths. Moreover, the heterogeneity analysis reveals that the disincentive effect is more pronounced in small enterprises, and those with high financing constraints and low institutional investor ownership. Meanwhile, the disincentive effect is also more pronounced for enterprises located in regions with underdeveloped digital financial inclusion and strong law enforcement. Overall, our findings contribute to a more comprehensive understanding of the impact of EPT on corporate risk-taking at the micro level and provide valuable insights for targeted policy enhancements.

Does enterprise digital transformation contribute to green innovation? Micro-level evidence from China

The synergy of digitalization and greening has emerged as a prominent means to achieve the goal of “carbon peaking and carbon neutrality”. Given its significant contribution to carbon emissions, the impact of digital transformation on green innovation in manufacturing enterprises remains a longstanding research hotspot. Therefore, based on the data from China A-share listed manufacturing companies spanning from 2007 to 2022, this paper empirically analyzes the influence and mechanism of digital transformation on green innovation. Our findings reveal that digital transformation can significantly promote green innovation in manufacturing enterprises, with a particularly pronounced effect on substantive green innovation. These conclusions withstand rigorous robustness tests. Mechanism analysis shows that digital transformation can facilitate green innovation by improving internal control quality and fostering industry-university-research cooperation. Moreover, our moderation analysis reveals that both equity incentives and compensation incentives strengthen the positive relationship between digital transformation and green innovation in manufacturing enterprises. Heterogeneity analysis proves that digital transformation exerts a more pronounced impact on green innovation of state-owned manufacturing enterprises, non-heavily polluted manufacturing enterprises, and enterprises located in regions with strong intellectual property protection. Furthermore, the transformation of digital underlying technologies is more conducive to fostering green innovation compared to practical application transformation. Subsequent investigation into the economic and social effects of green innovation indicates that it effectively reduces pollution emissions from manufacturing enterprises without compromising their development. Additionally, the emission reduction and income-generating effect resulting from digital transformation primarily manifest through substantive green innovation. This research expands upon the theory regarding the impact of digital transformation on green innovation in micro-manufacturing enterprises, providing empirical support for facilitating low-carbon transformations among manufacturing enterprises under the goal of “carbon peaking and carbon neutrality”.

Efficient leaching of valuable metals from spent lithium-ion batteries using green deep eutectic solvents: Process optimization, mechanistic analysis, and environmental impact assessment

The accumulation of over 11 million tons of spent lithium-ion batteries (LIBs) by 2030 highlights a critical environmental challenge posed by their large-scale retirement. The efficient recycling valuable metals from spent LIBs can both reduces environmental impact and mitigates the pressing issue of metal resource scarcity. In this context, deep eutectic solvents (DESs) have become a promising option as an eco-friendly solvent, exhibiting great potential for recycling spent LIBs. Therefore, this work proposed an innovative green DES system consisting of choline chloride (ChCl), DL-malic acid (MAL), and glycerol for the efficient leaching of valuable metals from spent LIBs. Comprehensive experiments were conducted to determine the optimum leaching conditions (130 °C, 60 g/L, MChCl:MAL:Glycerol of 1:1:3, 3 h), achieving high leaching efficiencies of 94.6% for Ni, 96.8% for Co, 93.8% for Mn, and 96.4% for Li. Through characterization techniques, kinetics studies, and density functional theory (DFT) calculations, the leaching process was predominantly governed by surface chemical reaction (1-(1-x)1/3 = kt) within the shrinking core model, exhibited activation energies of 49.89 kJ/mol, 47.66 kJ/mol, 50.51 kJ/mol, and 22.24 kJ/mol for Ni, Co, Mn, and Li, respectively. The propensity for DES to leach metal ions followed the order: Li > Co > Ni > Mn, determined by binding energy and energy gaps. Cl− and −COOH within the DES were capable of forming stable complexes with reduced transition metal ions, revealing an efficient coordination leaching mechanism. Additionally, a life cycle assessment (LCA) was conducted on the environmental impacts of the DES leaching process, confirming it as an effective and environmentally friendly method for recycling spent LIBs. This work avoided the employment of corrosive acids and alleviated the generally harsh conditions associated with DESs leaching, providing a viable solution for recovering spent LIBs.

Improving flexural performance of repaired C/C composites through Ti addition: Mechanism analysis

Ti-doped Ni-based solder was used as the repair agent to recover the flexural performance of the damaged carbon/carbon (C/C) composites. The effects of the contents of Ti on the microstructure, chemical compositions, and flexural strength were investigated. The thermal stress distribution and repair mechanism was studied by finite element analysis methods. The addition of an appropriate amount of Ti enhanced the wetting performance of the repair agent on the surface of C/C composites. Besides, the TiC hard particles formed at the interface provided strengthen effect, and form a gradient structure of coefficient of thermal expansion (CTE), thereby enhancing the interface bonding ability and improving the flexural performance of the repaired C/C composites. The flexural strength was the highest with a recovery rate of 92.6 % when the content of Ti was 5 wt%. This work provides a strategy for the engineering application and improving the damage repair of C/C composites.

Wormhole Mesoporous Silica Framework with Enhanced Thiol Loading for Improved Hg2+ Sequestration.

Thiol-functionalized mesoporous silica and materials potentially dedicated to diverse applications of composite materials, metal colloids, and metal catalysts, etc. Here, we developed a new synthesis route for 3-methacryloxypropyl trimethoxy silane (MPTMS) functionalized mesoporous silica (KIT-6), achieving a 71.5 % enhancement in thiol functionalization on KIT-6 surfaces. Characterization using XRD, TEM, BET, FTIR, Raman, 29Si NMR, XPS, and ICP-OES revealed structural and morphological features. XRD, TEM, and BET confirmed the three-dimensional structural stabilization of mesoporous silica with ~4 nm pore diameter and a surface area of 1451 m2 g-1. FTIR, Raman, and 29Si NMR studies established the mechanism of thiol functionalization, the formation of a new wormhole chain structural framework (WCSF), and stabilization through hydrogen bonding within the mesopores. The 29Si NMR spectra showed characteristic peaks (T3, T2, Q4, Q3) indicating self-condensed functionalized thiols with siloxane networks. XPS analysis validated enhanced thiol functionalization, indicating a structurally homogeneous WCSF suitable for mercury adsorption. ICP-OES measured a mercury adsorption capacity of 3199.6 mg g-1 for KIT-6, with an Hg2+/S ratio of 1.8, corroborated by molecular structure and mechanism analysis. This innovative thiol functionalization approach enhances the efficacy of applications such as extracting Hg2+ from contaminated sources.

Annealing impact on mechanical performance and failure analysis assisted with acoustic inspection of carbon fiber reinforced poly‐ether‐ketone‐ketone composites under flexural and compressive loads

AbstractThis study investigates the effect of the annealing treatment for carbon fiber reinforced Polyether‐ketone‐ketone (CF/PEKK) composite structures under flexural and compressive loadings through reference, pre‐damaged, and annealed sample sets. Significant recovery of pre‐existing damage is observed after the annealing process, following both flexural and compressive loading. Acoustic emission (AE) inspection is employed to monitor the failure behavior and assess the impact of pre‐damage and annealing on CF/PEKK composite. Initially, AE inspection reveals that the reference CF/PEKK material exhibits a notable fiber‐related failure with 85% of cumulative AE counts under flexural load, whereas matrix‐related failures are more pronounced with 92% cumulative AE counts under compressive load. Pre‐damages in the matrix alter the cumulative count percentages and initiation time that are related to matrix, interface, and fiber‐related failures, under flexural and compressive loadings. After annealing, each cumulative AE count percentages are comparable to reference sample values, due to changes in microstructure and relieving of residual stresses. The annealing effect is further validated through dynamic scanning calorimetry (DSC) analysis results with increased glass transition temperature (Tg) and degree of crystallization (Xc). Overall, these findings indicate that annealing treatment effectively restores structural integrity and improves the mechanical performance of CF/PEKK composites.Highlights Annealing aims for damage recovery in CF/PEKK under flexural and compressive loads. Significant damage recovery in CF/PEKK is seen after annealing. Annealing raises Tg and crystallinity, and enhances CF/PEKK structural integrity.

Aquaporin channels in desalination: Mechanical properties and operational load analysis

The scarcity of freshwater sources and the global demand for drinking water have spurred researchers worldwide to develop new and efficient desalination and water purification technologies. One promising method is desalination using aquaporin (AQP) channels, which are highly regarded for their biocompatibility and exceptional desalination efficiency. However, there is limited information on the mechanical behavior of these proteins under operational loads and how they maintain their function and resilience over time. This research employs all-atom molecular dynamics simulation to calculate the mechanical properties of the channels at the nanoscale. It also uses the finite element method to analyze the behavior of channels in vesicles embedded in composite plates at the macroscale under operational loads and conditions. Our research shows that the force on vesicle walls changes considerably with applied pressure, peaking at 14 pN at 55 bar. This variability highlights the need to carefully assess the weakest parts of the nanochannels, especially the helices HB and H1, which are susceptible to high strain and possible unfolding under extended stress. The results indicate the force tolerance threshold of the subsystems, guiding the application of appropriate force conditions for optimal performance and long-term system maintenance. Beyond desalination systems, the findings offer useful information for researchers working with aquaporin nanochannels in applications such as targeted drug release systems based on protein nanovalves, solid-state sequencing systems, and more.

Comparison of Compression of Occlusal Splint Materials: Laboratory Mechanical Analysis

Objective: To perform a compression test to fill the gap in the literature, assess the change in the construction angle (0º, 45º, 90º) as well as investigate physical and microstructural characteristics. Theoretical Framework: Comparisons of compression tests of occlusal splint materials printed in 3D are not described in the literature, which makes informed decision making on the choice of materials complicated. Method: The materials printed in 3D using the SLA method were resins. After printing, the materials were submitted to compression (calculating the Poisson coefficient), shore hardness and density tests. Results and Discussion: Dima® Print Ortho achieved the best results in terms of compression strength and maximum deformation in the vertical position (90º) in comparison to the other materials, followed by Self BioPrint Splint Hard, PriZma 3D Bio Splint and Cosmos Splint. Research Implications: Three-dimensional devices through additive fabrication can be used in the treatment of bruxism. The position to obtain greater compression strength is vertically at 90º. Originality/Value: This study contributes to the literature by demonstrating the efficacy of 3D printing of occlusal devices using the resin polymerization method, highlighting the superior dimensional accuracy and mechanical properties of the materials employed. Furthermore, it addresses the sustainability of the process by promoting material waste reduction during fabrication. These findings have significant implications for optimizing the production of occlusal devices in clinical settings.

Analysis of the third class mechanism using the modeling method in the Mathcad software environment

Purpose. To carry out a kinematic analysis of a flat twelve-link hinged mechanism with three leading links, the basis of which is a structural group of links of the third class of the fourth order with rotational kinematic pairs, which is used in technological equipment. Methodology. The kinematic study of a flat complex mechanism of the third class with three leading links was performed using the mathematical modeling method in the Mathcad software environment. Findings. Using the method of mathematical modeling, the mechanism was presented in the form of free vectors built on its links, for which, taking into account the presence of three leading links, three vector contours were selected, which made it possible to draw up a system of vector equations of their closedness with further solving by a numerical method in the Mathcad software environment. The functions of the rotation angles of the mechanism links, their angular velocities and accelerations were obtained in analytical and graphical form depending on the rotation angle of the first driving crank of the mechanism, the calculation of the angular velocities and accelerations of all the driven links of the mechanism was performed. Originality. A sequence was developed and a kinematic study of a complex planar mechanism of the third class with three leading links was done, the basis of which is a structural group of links of the third class of the fourth order. Schematic modeling of the mechanism with three leading links was performed, a visualization schedule of its kinematic scheme was built, and a valid version of its assembly was obtained from many possible ones, for which the values of kinematic parameters of all its links were determined. Practical value. An analysis of the effect of the kinematic parameters of the three leading links of the third-class mechanism on the movement of the working body of the technological equipment was carried out. From the analysis of the obtained research results for the cycle of the mechanism the reason was found for the incomplete technological stoppage of the link, which should provide the working body of the machine for the required period of time. Recommendations of the elimination were made to identify the deficiency and proposals for the need to improve the drive of this equipment.

Analysis of degradation mechanism in polycrystalline silicon thin-film transistors under dynamic off-state stress with fast transition time

Abstract This study represents the investigation into the degradation of polycrystalline silicon (poly-Si) thin-film transistors (TFTs) under dynamic off-state stress, with a focus on transition times as rapid as 1 nanosecond (ns). The study found that dynamic off-state stress with larger amplitude leads to more severe device degradation. Unlike previous studies, both the rising time (t r ) and falling time (t f ) of the pulse significantly influence the hot carrier (HC) degradation in the poly-Si TFTs. The on-state current degradation rate (ΔI on ) after 104 s stress dramatically increases from 11.8% to 80.8% when t r decreases from 500 ns to 1 ns. When t f decreases from 500 ns to 1 ns, ΔI on also dramatically increases from 22.9% to 69.2%. Combined with transient simulations, the source of the carrier for HC degradation is clarified and consequently, a non-equilibrium PN junction degradation model modulated by accumulated electrons is developed.

Integrated Transcriptomic and Proteomic Analysis of Nutritional Quality-Related Molecular Mechanisms in “Longjia”, “Yangpao”, and “Niangqing” Walnuts (Juglans sigillata)

In this study, “Longjia (LJ)” and “Yangpao (YP)”exhibited higher contents of major nutrients compared to “Niangqing (NQ)” walnuts. The combination of transcriptome and proteome by RNA sequencing and isotope labeling for relative and absolute quantification techniques provides new insights into the molecular mechanisms underlying the nutritional quality of the three walnut species. A total of 4146 genes and 139 proteins showed differential expression levels in the three comparison groups. Combined transcriptome and proteome analyses revealed that these genes and proteins were mainly enriched in signaling pathways such as fatty acid biosynthesis, protein processing in endoplasmic reticulum, and amino acid metabolism, revealing their relationship with the nutritional quality of walnut kernels. This study identified key genes and proteins associated with nutrient metabolism and accumulation in walnut kernels, provided transcriptomic and proteomic information on the molecular mechanisms of nutrient differences in walnut kernels, and contributed to the elucidation of the mechanisms of nutrient differences and the selection and breeding of high-quality walnut seedlings.

Dynamics of Photoinduced Charge Carriers in Metal-Halide Perovskites

The measurement and description of the charge-carrier lifetime (τc) is crucial for the wide-ranging applications of lead-halide perovskites. We present time-resolved microwave-detected photoconductivity decay (TRMCD) measurements and a detailed analysis of the possible recombination mechanisms including trap-assisted, radiative, and Auger recombination. We prove that performing injection-dependent measurement is crucial in identifying the recombination mechanism. We present temperature and injection level dependent measurements in CsPbBr3, which is the most common inorganic lead-halide perovskite. In this material, we observe the dominance of charge-carrier trapping, which results in ultra-long charge-carrier lifetimes. Although charge trapping can limit the effectiveness of materials in photovoltaic applications, it also offers significant advantages for various alternative uses, including delayed and persistent photodetection, charge-trap memory, afterglow light-emitting diodes, quantum information storage, and photocatalytic activity.

Analysis of the mechanical properties and micro-reinforcement mechanisms of loose accumulated sandy soil improved with polyvinyl alcohol and sisal fiber

As one of the world’s most fragile and sensitive ecological regions, Xizang risks significant environmental damage from using traditional materials, including cement and lime, to improve and reinforce loose accumulated sandy soil slopes. To address this issue, this study utilized a low-concentration biodegradable polyvinyl alcohol (PVA) solution combined with sisal fibers (SFs) to stabilize loose accumulated sand in southeastern Xizang. A series of physical, mechanical, and microscopic analyses was conducted to evaluate the properties of the treated sand. The results indicated the following. 1) The stress-strain curves of the improved samples exhibited an elastic-plastic relationship. Failure was observed in two stages. At a strain of 3% or less, the samples demonstrated elastic deformation with a linear increase in stress, whereas the deviator stress increased rapidly and linearly with an increase in axial strain. Once the strain exceeded 3%, the deformation became plastic with a nonlinear increase in the stress-strain relationship, and the growth rate of the deviator stress gradually decreased and leveled off. 2) Under varying confining pressure conditions, the relationship curve between the maximum (σ1-σ3)max∼σ3 for both untreated loose accumulated sandy soil and soil improved with the PVA solution, and the sisal fiber was approximately linear. 3) The SFs created a skeletal-like network that encased the soil particles, and the hydroxyl functional groups in the PVA molecules bonded with both the soil particles and the fiber surface, thereby enhancing the interfacial properties. This interaction resulted in a tighter connection between the soil particles and SFs, which improved the stability of the structure. 4) The incorporation of a PVA solution and SFs significantly enhanced the mechanical strength and deformation resistance of the loose accumulated sandy soil. The optimal ratio for the improved soil was SP = 3% and SL = 15 mm, which increased the cohesion from 24.54 kPa in untreated loose accumulated sandy soil to 196.03 kPa. These findings could be applied in engineering practices to improve and reinforce loose accumulated sandy soil slopes in southeastern Xizang and provide a theoretical basis for such applications.

Experimental evaluation and simulation of myoblast cell alignment on the UV-irradiated liquid crystalline elastomers as a versatile tissue-engineered Scaffolding material

Efforts to develop versatile tissue-engineered scaffolds mimicking the functions of extracellular matrices (ECMs) have led to the emergence of liquid crystalline elastomers (LCEs) as promising materials. Here, thiol-acrylate-based LCEs forming a nematic phase upon UV irradiation were synthesized, and their biological compatibility was evaluated using C2C12 myoblast cells. Prior to UV exposure, some characteristics, e.g., phase transition temperature (TNI), order parameter, and reaction time, of the as-synthesized LCEs are characterized for property optimization. Fourier-transform infrared spectroscopy revealed that thiol-acrylate Michael addition polymerization was successful, judged by the disappearance of the characteristic peaks of thiol and acrylate groups. Differential scanning calorimetry thermograms and dynamic mechanical thermal analysis curves showed TNI values at ca. 49 °C, at which point the nematic phase is the dominant morphology. Moreover, the cross-linking density, the fixing, and the recovery ratios for the sample with optimal properties (i.e., LCE3) were determined to be 10.3 mol/cm3, 97.2 % and 91 %, respectively. Assessment of mesomorphism and roughness demonstrated the suitability of LCE3 for cell culture. Subsequent studies on adhesion, viability, differentiation, and proliferation of cultured myoblast cells, coupled with particle image velocimetry simulation, highlighted the potential of UV-irradiated LCE3 as a promising scaffold material for inducing surface morphology-induced cellular alignment and interactions.