Mechanical Analysis Research Articles

Self-healing behavior of metallopolymers in complex.

This current study focusses on the investigation of the self-healing abilities of metallopolymers containing different kinds of metal complexes, which were processed by direct digital light processing (DLP) based three-dimensional (3D) printing. For this purpose, 2‑phenoxyethyl acrylate is mixed with ligand-containing monomers either based on triphenylmethyl(trt)-histidine or terpyridine, respectively. Either zinc(II) or nickel(II) salts are successfully applied for a complexation of the ligand monomers in solution and, subsequently, photopolymerization is performed. The thermo-mechanical properties of the obtained metallopolymers were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) as well asdynamic mechanical thermal analysis (DMTA). Multiple damages with defined forces ranging from 20 to 1500 mN were introduced into the 3D-structures and successfully healed within 24h at 70°C or 120°C, respectively without losing the structural integrity of the overall 3D-structures. Herein, excellent healing efficiencies up to 97% were determined. Consequently, these hollow structures not only feature very good self-healing abilities but also excellent retention of the 3D-structure at and above the healing temperature.

Analysis of Mechanisms of Mandible Fractures by Lateral Impact: A Biomechanical Approach Using Finite Element Models

Background/Aim: The purpose of this study was to reproduce a lateral fall using a computer simulation model and to clarify the circumstances of mandible fracture caused by a lateral impact. Material and methods: Fall scenarios were reconstructed using a computer simulation with finite element models. The fall condition was set as a fall from the head direction, which would cause facial injuries. In each simulation, the effective plastic strain of the mandible and its site were determined. Analysis of variance was performed to determine which factors had a significant effect on the maximum effective plastic strain of the mandible. Results: Significant differences with p-values less than 0.001 were found for the following factors: pitch angle, lateral bending angle, impact object, combination of pitch angle and lateral bending angle, and combination of pitch angle and impact object. In most cases with higher values of effective plastic strain, which can cause mandibular fractures, the site was found at the condylar process or mandibular angle of the attacked side. Conclusion: If the patient falls laterally and their face makes contact with a protruding object, medical professionals can predict fractures of the upper part of the mandibular angle and the condyle of the affected side.

Moracin M promotes hair regeneration through activation of the WNT/β-catenin pathway and angiogenesis.

Hair follicle growth depends on the intricate interaction of cells within the follicle and its vascular supply. Current FDA-approved treatments like minoxidil have limitations, including side effects and the need for continuous use. Moracin M, a compound from Moraceae family, was investigated for its effects on hair growth and vascular regeneration. In our study, Moracin M significantly increased cell proliferation in human dermal papilla cells (hDPCs) during both the anagen and catagen phases and promoted cell migration in human umbilical vein endothelial cells (HUVECs) without cytotoxicity at concentrations up to 50 µM. Mechanistic analysis revealed that moracin M enhanced Wnt3a, GSK-3β phosphorylation and increased non-phospho β-catenin levels, activating Wnt signaling and upregulating transcription factors LEF, TCF, and AXIN2. This resulted in elevated levels of growth factors VEGF, FGF2, KGF, HGF and MYC in hDPCs, effects comparable to those of minoxidil. Additionally, moracin M significantly increased protein and mRNA levels of VEGF, FGF2, and KGF in hDPCs under IFN-γ-induced inflammatory conditions. Moracin M treatments also resulted in notable wound width reductions in a dose-dependent manner. Further investigation showed that moracin M stimulated MMP-2 and MMP-9 expression. These findings indicate that moracin M significantly enhances hair growth through the promotion of cell proliferation and angiogenesis, particularly via the activation of the Wnt signaling pathway in dermal papilla cells, presenting it as a promising therapeutic alternative to current treatments.

ESG Rating Uncertainty and the Cost of Debt Financing

ABSTRACTUsing A‐share listed companies in 2011–2022 as a research sample, this study manually calculates and constructs Environment, Social and Government (ESG) rating uncertainty at the level of Chinese listed companies and examines whether and how ESG rating uncertainty affects firms' cost of debt financing. The empirical results demonstrate that ESG rating uncertainty raises firms' debt financing costs. After a string of robustness tests, the results are still robust. Mechanism analysis identifies credit risk and corporate reputation as the primary channels driving this relationship. Furthermore, high levels of firm's internal control, region's public environmental concerns and the level of financial agglomeration are conducive to mitigating the adverse effects of ESG rating uncertainty. This article enriches the research on the impact of ESG rating uncertainty on microeconomic agents in emerging markets and provides new perspectives to alleviate corporate financing constraints.

Sustainable Supercritical Carbon Dioxide Extraction of Value-Added Lignan from Sesame Meal: Achieving Green Neuroprotection and Waste Valorization by Optimizing Temperature, Solvent, and Pressure

In pursuing sustainable health solutions and growing demand for neuroprotective interventions, the industry demands alternative green extraction technologies to valorize agri-food by-products. This study aimed to develop an optimized supercritical carbon dioxide extraction to isolate sesame meal’s functional compound (lignans) and assess their neuroprotective effects. Extraction was performed at various pressures (2–4 kpsi), temperatures (40–60 °C), co-solvent concentrations (2–25 mol% ethanol), and CO2 collection segments (0–100 NL) to systematically analyze extraction parameters. Extracts were analyzed quantitatively using high-performance liquid chromatography followed by neuroprotective mechanisms analysis through PC12 neural cell and ischemic stroke models. The results showed that adding ethanol enhanced the polarity and density of supercritical CO2, improving the extraction efficiency of polar lignans. Optimal extraction conditions (4 kpsi, 50 °C, 10 mol% ethanol) yielded the highest sesamol, sesamin, and sesamolin. Extracts showed remarkable protective capabilities when subjected to oxygen–glucose deprivation (OGD) conditions simulating ischemic stress, preventing the enhancement of lactate dehydrogenase activity. Relatively low extract concentrations (25–100 μg/mL) significantly mitigated cellular damage induced by short and extended OGD conditions. The findings revealed green extraction methodologies’ capability to transform sesame meal, a food processing waste, into value-added compounds, in line with sustainable development goals for responsible and sustainable food production, particularly SDGs 3, 9, 12, and 13.

Mechanical analysis of 3D printed dental restorations manufactured using different resins and validation with FEM analysis

PurposeThe aim of this study was to compare the wear and fracture resistance of single crowns produced from newly developed 3D printer resins used to produce permanent crowns and currently used composite CAD/CAM discs, after being thermomechanically aged in a chewing simulator.Materials and methodsA total of 112 stainless steel die models simulating mandibular left first molars were produced, 8 for each group. Single crowns were produced from 3 different discs (Grandio Voco [GR], breCAM HIPC [HC], and Shofu HC [SF]) by CAD/CAM milling method and manufactured from from 4 different permanent composite resins (Nexdent C&B MFH [ND], Permanent Bridge Saremco [PB], VarseoSmile Crownplus [VSC], and Şenertek P-Crown [PC]) using the 3D printing method. Stereomicroscopy, scanning electron microscope (SEM) and Finite Element Method (FEM) analysis was performed. Data were analyzed using ANOVA, paired-t tests and Tukey’s HSD test (alpha = 0.05).ResultsAs a result of thermomechanical aging, significant difference was found between the groups in wear and fracture resistance (P < .05). The highest wear resistance was found in the VSC group, and the lowest wear resistance in the PC group. As a result of the compression test, the highest fracture resistance was noted in the GR group and the lowest in the PC group. FEM analysis performed to validate fracture experiments showed an 87% similarity to the in-vitro data.ConclusionsThe crowns in all groups produced by CAD/CAM milling and 3D printing provided acceptable in vitro wear and fracture resistance for clinical application. The wear and fracture resistance of resin-based materials should be supported by clinical studies.

NiTi Alloy Quasi-Zero Stiffness Vibration Isolation Structure with Adjustable Mechanical Properties

Despite the significant engineering applications of vibration isolation structures, there remain challenges in adjusting low-frequency isolation performance. To tackle this issue, this study proposes a temperature-controlled quasi-zero stiffness vibration isolation structure utilizing NiTi shape memory alloys. The stiffness and vibration isolation performance of the structure can be adjusted by modifying the heat treatment process and temperature variations of the alloy. The vibration isolation system is composed of vertical and horizontal alloy beams, with structural mechanics analysis performed to develop both static and dynamic theoretical models. The study investigates the effects of the heat treatment process on the phase transition characteristics and mechanical properties of nickel-titanium alloys, and analyzes the correlation between the heat treatment parameters of alloy beams and the stiffness performance of vibration isolation structures. By applying temperature variations to the alloy beams, the stiffness and vibration isolation performance of the entire structure can be dynamically adjusted. This research provides theoretical guidance for achieving adjustable vibration isolation performance across low-frequency and wide ranges, offering promising prospects for the application of vibration isolation structures in dynamic environments.

Intelligent Monitoring System for Deep Foundation Pit Based on Digital Twin

Underground space development has significantly increased the depth, scale, and complexity of foundation pit engineering. However, monitoring systems lack mechanical analysis models and fail to predict and control construction risks. Additionally, the foundation pit model could not be updated based on on-site observed data, leading to inaccurate predictions. This study proposes a DT modeling framework for foundation pits, which is used to simulate, predict, and control the risks associated with the entire excavation process. Consequently, based on the DT modeling framework, a DT foundation pit model (DTFPM) was established using modeling and updating algorithms. This study summarizes and identifies the key modeling parameters of foundation pits. A parametric modeling algorithm based on ABAQUS (v2020) was developed to drive the excavation pit modeling process within seconds. Furthermore, an inverse analysis optimization algorithm based on genetic algorithms (GA) and real-time observed deformation was employed to update the elastic modulus of the soil. The algorithm supports parallel computing and can converge within 10 generations. The prediction error of the model after inverse analysis can be reduced to within 10%. Finally, the authors applied DTFPM to establish an intelligent monitoring system. The focus is on real-time and predictive warnings based on the monitoring deformation of the current construction step and the updated model. This study analyzes a Beijing project case to verify the effectiveness of the system, demonstrating the practical application of the proposed method. The results showed that the DTFPM could accurately simulate the deformation behavior of the foundation pit. The system could provide more timely and accurate safety warnings. The proposed method can potentially contribute to the intelligent construction of foundation pits in the future, both theoretically and practically.

Er2O3-Doped Lead Borate Glasses: Advanced Optical and Radiation Shielding Performance

Abstract A new glass system with the composition 60B2O3 + 30PbF2 + (10−x)K2O + x Er2O3 (x = 0 to 3 mol%) were synthesized using the melt-quenching technique and comprehensively analyzed to evaluate their structural, optical, mechanical, and radiation shielding properties. Increasing Er2O3 concentration enhanced the density (from 4.260 to 4.89 g/cm3) and reduced the molar volume (from 29.28 to 28.98 cm3/mol), indicating a denser and more compact glass matrix. Optical studies revealed increased UV absorbance, a red shift in the cutoff wavelength, and a reduction in the optical energy gap from 3.487 to 3.335 eV (direct transitions). Urbach energy values increased from 0.722 to 1.083 eV, signifying heightened structural disorder. Enhanced refractive index and extinction coefficients further underscored the glasses’ potential for optical applications. Mechanical analyses demonstrated a significant increase in all elastic moduli, including Young’s, bulk, and shear moduli, with Er2O3 incorporation, indicating improved rigidity and mechanical stability. The radiation shielding performance of the glasses was assessed across photon energies of 0.015–15 MeV, incorporating both experimental data and machine learning (ML)-based predictions of mass attenuation coefficients (MAC). The ML model, developed using a neural network architecture, successfully predicted MAC values with high accuracy, demonstrating excellent agreement with XCOM-calculated results. Key shielding parameters, including half-value layer (HVL), effective atomic number (Zeff), and buildup factors (EABF and EBF), improved significantly with higher Er2O3 content. BPKE3 glass, with the highest Er2O3 concentration, exhibited the best shielding efficiency, outperforming conventional shielding materials in terms of lower HVL and buildup factors, coupled with higher MAC and Zeff values. This study highlights the dual role of Er2O3-doped lead borate glasses as efficient optical and radiation shielding materials. Machine learning effectively predicts shielding parameters, aiding material optimization for applications in nuclear, medical, and industrial fields.

Exploration of Mass Transfer and Electrochemical Performance of SOFCs through the Anode Structure: Experiments, Modeling, and Mechanism Analysis

Exploration of Mass Transfer and Electrochemical Performance of SOFCs through the Anode Structure: Experiments, Modeling, and Mechanism Analysis

Structure and properties of chitosan plasticized with hydrophobic short-chain fatty acid cosolvent.

The application of chitosan in packaging has always been limited due to its brittle and hygroscopic nature. In this study, hydrophobic short-chain fatty acids (SCFAs) were utilized to modify chitosan to overcome this issue. For the first time, hydrophobic SCFAs, typically hexanoic acid and its homologs, were found to be able to dissolve chitosan in water as well as its hydrophilic analog. After water was removed through evaporation, hydrophobic SCFA-modified chitosan films were obtained. The results of mechanical testing and DSC analysis confirmed that these hydrophobic SCFAs could effectively plasticize the chitosan film. Moreover, water contact angle measurements revealed that the hydrophilicity of these plasticized chitosan films was significantly reduced. The findings from the moisture uptake experiments indicated that linear hydrophobic SCFAs reduced the hygroscopicity of the chitosan film. Additionally, the crystal structures, thermal and gas barrier properties, and antibacterial activities of these hydrophobic SCFA-modified films were systematically examined and compared with those of hydrophilic SCFA-modified chitosan. This study presents an innovative and practical method for modifying chitosan films by regulating the structure of the cosolvent, thereby facilitating the real-world application of chitosan-based food packaging materials.

Characterization of phase-changing materials as stabilized thermal energy storage in impregnated biomaterial

In recent years, impregnation of biomaterial (wood veneers) with eutectic phase change materials (PCM) has been investigated to increase the thermal capacity of bio-based materials, which significantly affects the thermal capacity, especially in building applications requiring low heat. In this study, four eutectic phase change materials were prepared using three different fatty acids and impregnated on two wood veneers (oak and ash). The structural characterization of the prepared eutectic mixtures was examined using FT-IR, while the morphological properties of the wood veneers were examined by scanning electron microscopy (SEM). The thermal performance was analyzed via differential scanning calorimetry (DSC) and their thermo-mechanical properties by dynamic mechanical analysis (DMA). Additionally, the thermal conductivity ( k values) was determined. From the results obtained, it was possible to prepare eutectic mixtures with melting temperatures around 30°C with heat capacities up to 225.5 J/g. It was also generally determined that eutectic PCM, prepared from mixtures of lauric acid and palmitic acid, have lower thermal conductivity but show higher storage and loss modulus for the wood coatings leading to a balance between mechanical and thermal properties.

Enhancing the performance of polyfarnesene-based bio-rubbers with surface-modified cellulose nanocrystals and nanofibers

As the rubber industry seeks sustainable alternatives to mitigate its environmental impact, this study introduces a biobased approach using polyfarnesene rubber reinforced with plasma-modified cellulose nanocrystals (MCNC) and nanofibers (MCNF). The nanocellulose was modified by plasma-induced polymerization using trans-β-farnesene and was characterized by FTIR, XPS, XRD, TGA, and SEM to confirm the grafting of farnesene-derived polymer chains onto the cellulose surface, demonstrating the successful modification and integration of the nanoparticles. Polyfarnesene bio-based rubbers were synthesized through two different polymerization techniques: solution-based coordination polymerization (PFA1) and emulsion-based free radical polymerization (PFA2). The modified nanoparticles were incorporated into these rubber matrices at 2–12 wt% and vulcanized by incorporation of sulfur. The performance of bio-rubbers reinforced with cellulose nanoparticles was analyzed by tensile test and dynamic mechanical analysis (DMA). Mechanical tests focused on tensile strength, Young’s modulus, and elongation at break showed that incorporation of 12 wt% modified MCNF into the PFA1 and PFA2 increased tensile strength by 56% and 22%, and Young’s modulus by 27% and 58%, respectively (compared to the neat rubber matrix), while elongation at break decreased with increasing MCNF content. The addition of MCNC into PFA1 and PFA2 improved the deformation resistance values of 205% for PFA1-MCNC12% and 49% for PFA2-MCNC12%. Dynamic mechanical analysis showed an increase in storage modulus and a shift towards higher glass transition temperatures, indicating stronger filler-matrix interactions. The results demonstrate that plasma-modified cellulose nanoparticles effectively enhance the mechanical properties of polyfarnesene bio-rubbers, offering a sustainable alternative with performance competitive to synthetic rubbers.

A Study of the Impact of Manufacturing Input Digitization on Firms’ Organizational Resilience: Evidence from China

In the era of digital economy, boosting investment in digitalization serves as a crucial approach for the manufacturing sector to bolster its robustness and forge competitive edges. Utilizing data from listed manufacturing firms spanning 2007–2022, this paper investigates how the digital transformation of manufacturing inputs influences the organizational resilience of businesses and the underlying mechanism. The findings indicate that investment in digital technologies significantly enhances organizational resilience. The mechanism analysis suggests that investing in digitization will enhance organizational resilience by increasing the firm’s technological innovation capacity, and thus financial redundancy positively moderates the positive impact of digitization on organizational resilience. Heterogeneity analysis shows that there is heterogeneity among different enterprise sizes and industry intensities; enterprises should adjust their digitalization investment strategies in a timely manner according to their industries and enterprise sizes to strengthen and consolidate their organizational resilience. The results of this research provide practical proof and guidance for the development of the manufacturing sector, small and medium-sized enterprises (SMEs), and the strengthening of organizational resilience.

CSR and corporate science

ABSTRACT Corporate social responsibility (CSR) is a commitment to sustainability that goes beyond financial goals, creating an enabling environment for the generation of corporate science. This study utilizes hand-sorted data on corporate-authored papers to investigate the impact of CSR on corporate science. The empirical results demonstrate a significant positive correlation between CSR and corporate science. This finding is corroborated by robustness tests, including fixed effects and instrumental variable methods. Mechanism analysis reveals that CSR positively influences corporate science through human capital, signaling effects, and organizational culture. Further analysis indicates that the positive impact of CSR on corporate science is more pronounced in corporations with high scientific density and independent central research institutes. Overall, our research clarifies the relationship between CSR and corporate science, enriching the literature on corporate governance and innovation.

Failure mechanism and mechanical analysis in horizontal bedded surrounding rock with high in-situ stress

Failure mechanism and mechanical analysis in horizontal bedded surrounding rock with high in-situ stress

Multi-GPU Acceleration for Finite Element Analysis in Structural Mechanics

This work evaluates the computing performance of finite element analysis in structural mechanics using modern multi-GPU systems. We can avoid the usual memory limitations when using one GPU device for many-core computing using multiple GPUs for scientific computing. We use a GPU-awareness MPI approach implementing a suitable smoothed aggregation multigrid for preconditioning an iterative distributed conjugate gradient solver for GPU computing. We evaluate the performance and scalability of different models, problem sizes, and computing resources. We take an efficient multi-core implementation as the reference to assess the computing performance of the numerical results. The numerical results show the advantages and limitations of using distributed many-core architectures to address structural mechanics problems.

Caring for the mental health of Afghan refugee youth through a decolonial paradigm: A qualitative analysis of distress, coping mechanisms, and priorities for treatment.

Despite the compounded adversities that displaced youth must navigate throughout their forced migration, they consistently exhibit steadfastness in caring for themselves and their families. Extant scholarship, however, often frames these individuals as needy and inept at informing the models of mental health care they are offered. In this study, we use semistructured interviews to learn from the experiences of Afghan refugee youth (N = 34; M age = 19; range 18-24) who were resettled in the United States after the United States withdrawal from Afghanistan in August of 2021 and explore their insights that can inform decolonial and equitable mental health services. Specifically, we elucidate their most salient sources of psychological distress, current coping mechanisms, and priorities for treatment, with a specific focus on the unique experiences of accompanied versus unaccompanied youth. Unaccompanied youth reported more frequent and intense sources of distress, including pre-resettlement (e.g., exposure to life-threatening sociopolitical conflicts) and post-resettlement challenges (e.g., limited access to basic resources and legal status precarity). Youth used faith-based, relationship-based, and ethnocultural-based mechanisms of coping. While 62% of participants reported doubts about the usefulness of mental health care, most of those who expressed an openness to treatment prioritized clinicians who have personal experience in navigating common challenges among refugees. We situate these findings within decolonial and intersectional theoretical frameworks that capture the nuances of Afghan refugee experiences and offer recommendations for ensuring refugee youth's rights to access equitable mental health services.

Numerical analysis of collision mechanism that causes particle tribocharging in dry powder inhaler

Chronic obstructive pulmonary disease (COPD) is induced by inhalation of toxic substances such as cigarettes and air pollution. Dry powder inhalers (DPIs) are the primary treatment for these diseases. However, they have some problems, such as residuals in a capsule caused by electrostatic force before reaching the human lungs. This study investigated the particle tribocharging mechanism in a DPI using a tandem differential mobility analyzer (TDMA) and a combined discrete element method and computational fluid dynamics (DEM-CFD) approach. In the TDMA experiment, the charging state of the particles changed from negative to positive charge in the DPI device fabricated by the 3D printer. This is because tribocharging is caused by particle–particle collisions and particle–wall collisions. In the numerical simulation, particle–wall collisions occurred more frequently than particle–particle collisions. Therefore, the particle–wall collisions change the charging state of the particle in the DPI device. These results suggest that collisions between particles and walls of the device cause the particles to become charged, leading to a decrease in their deposition in the deeper regions of the lungs. Moreover, the large turbulence kinetic energy of the airflow in the DPI device caused particle–wall collisions because the particles were widely dispersed in the DPI device. These results suggest that optimum turbulence kinetic energy is necessary to reduce particle aggregation and improve the delivery efficiency of DPIs to the human lungs.Graphical

Fabrications and Properties of Heteroatom-Based Co-Doped Biochar for Environmental Application: A Review

For the past few years, biochar has emerged as a promising material for the removal of various pollutants from aquatic environments, owing to its advantageous characteristics, such as tunable porosity, abundant surface functional groups, ease of modification, and relative stability. Co-doping biochar with heteroatoms significantly enhances its surface properties by introducing additional functional groups and surface defects, which facilitate the adsorption and catalytic degradation of pollutants. This review conducts bibliometric analyses of relevant publications, synthesis methodologies, applications, and reaction mechanisms of co-doped biochar as an adsorbent and catalyst for contaminant removal, due to the synergistic effects of doping elements and biochar features. Furthermore, co-doping strategies and associated properties including specific surface area (SSA), surface functional groups, and defects of biochar are analyzed. Finally, future research directions are proposed to improve the efficiency of biochar in water and soil remediation applications. In summary, this review advances the frontier of research on heteroatom-based co-doped biochar and offers new insights into strategies for effective contaminant removal.