Mechanical Analysis Research Articles

Correction: Quantitative Analysis of Physical Stability Mechanisms of Amorphous Solid Dispersions by Molecular Dynamic Simulation

Correction: Quantitative Analysis of Physical Stability Mechanisms of Amorphous Solid Dispersions by Molecular Dynamic Simulation

Modeling and analysis of a non-linear compliant rolling-sliding contact mechanism when subjected to a periodic motion input

Modeling and analysis of a non-linear compliant rolling-sliding contact mechanism when subjected to a periodic motion input

Deformation Behavior of Inconel 625 Alloy with TPMS Structure

Triply periodic minimal surfaces (TPMSs) are known for their smooth, fully interconnected, and naturally porous characteristics, offering a superior alternative to traditional porous structures. These structures often suffer from stress concentration and a lack of adjustability. Using laser powder bed fusion (LPBF), we have fabricated Inconel 625 sheet-based TPMS lattice structures with four distinct topologies: Primitive, IWP, Diamond, and Gyroid. The compressive responses and energy absorption capabilities of the four lattice designs were meticulously evaluated. The discrepancies between theoretical predictions and the fabricated specimens were precisely quantified using the Archimedes’ principle for volume displacement. Subsequently, the LPBF-manufactured samples underwent uniaxial compression tests, which were complemented by numerical simulation for validation. The experimental results demonstrate that the IWP lattice consistently outperformed the other three configurations in terms of yield strength. Furthermore, when comparing energy absorption efficiencies, the IWP structures were confirmed to be more effective and closer to the ideal performance. An analysis of the deformation mechanisms shows that the IWP structure characteristically failed in a layer-by-layer manner, distinct from the other structures that exhibited significant shear banding. This distinct behavior was responsible for the higher yield strength (113.16 MPa), elastic modulus (735.76 MPa), and energy absorption capacity (9009.39 MJ/m3) observed in the IWP configuration. To examine the influence of porosity on structural performance, specimens with two varying porosities (70% and 80%) were selected for each of the four designs. Ultimately, the mechanical performance of Inconel 625 under compression was assessed both pre- and post-deformation to elucidate its impact on the material’s integrity.

Mechanism and Characterization of Bicomponent-Filler-Reinforced Natural Rubber Latex Composites: Experiment and Molecular Dynamics (MD)

The incorporation of reinforcing fillers into natural rubber latex (NR) to achieve superior elasticity and mechanical properties has been widely applied across various fields. However, the tendency of reinforcing fillers to agglomerate within NR limits their potential applications. In this study, multi-walled carbon nanotube (MWCNT)–silica (SiO2)/NR composites were prepared using a solution blending method, aiming to enhance the performance of NR composites through the synergistic effects of dual-component fillers. The mechanical properties, dispersion behavior, and Payne effect of three types of composites—SiO2/NR (SNR), MWCNT/NR (MNR), and MWCNT-SiO2/NR (MSNR)—were investigated. In addition, the mean square displacement (MSD), fractional free volume (FFV), and binding energy of the three composites were simulated using molecular dynamics (MD) models. The results showed that the addition of a two-component filler increased the tensile strength, elongation at break, and Young’s modulus of NR composites by 56.4%, 72.41%, and 34.44%, respectively. The Payne effect of MSNR was reduced by 4.5% compared to MNR and SNR. In addition, the MD simulation results showed that the MSD and FFV of MSNR were reduced by 21% and 17.44%, respectively, and the binding energy was increased by 69 times, which was in agreement with the experimental results. The underlying mechanisms between the dual-component fillers were elucidated through dynamic mechanical analysis (DMA), a rubber process analyzer (RPA), and field emission scanning electron microscopy (SEM). This study provides an effective reference for broadening the application fields of NR.

Study of Fluid Flow Characteristics and Mechanical Properties of Aviation Fuel-Welded Pipelines via the Fluid–Solid Coupling Method

The welded pipeline structure of aircraft fuel is a complex and diverse entity, significantly influenced by fluid–solid coupling. The refined aviation fuel-welded pipeline model plays a pivotal role in the investigation of its fluid–solid coupling mechanical properties. However, the mechanical analyses of pipelines with welded structures frequently simplify or ignore the influence of the weld zone (WZ). Consequently, these analyses fail to reveal the complex interactions between different weld zones in detail. In this study, a comprehensive and precise fuel-welded pipeline refinement model is developed through the acquisition of microstructural dimensions and mechanical parameters of the weld zone via metallographic inspection and microtensile testing. Additionally, the influence of clamps and brackets under airborne conditions is fully considered. Furthermore, the numerical simulation results are compared and verified using modal and random vibration tests. This paper addresses the impact of diverse fluid characteristics on the velocity field, pressure field, and stress in disparate areas, and it also conducts an investigation into the random vibration characteristics of the pipeline. The results demonstrate that the fluid pressure and velocity exert a considerable influence on the fluid flow state and structural stress distribution within the pipeline. An increase in flow velocity and alteration to the pipeline geometry will result in a change to the local velocity distribution, which in turn affects the distribution of the fluid pressure field. The highest stresses are observed in the weld zone, particularly at the junction between the weld zone and the heat-affected zone (HAZ). In contrast, the stresses in the bend region exhibit a corrugated distribution in both the axial and circumferential directions. An increase in fluid pressure has a significant impact on the natural frequency of the pipeline. This study enhances our comprehension of the mechanical properties of aircraft fuel lines with fluid–solid coupling and provides a foundation and guidance for the optimal design of fuel-welded lines.

Identification of compounds against atherosclerosis induced by ox-LDL based on cell extraction/UPLC–MS/MS from mulberry twigs and their mechanistic analysis

BackgroundMulberry twigs, a traditional Chinese medicinal and agricultural byproduct, contain bioactive compounds with anti-atherosclerotic potential. This study aims to identify and evaluate the effects of key compounds in mulberry twig extracts (MTEs) on oxidized low-density lipoprotein (ox-LDL)-induced human umbilical vein endothelial cells (HUVECs), with a focus on understanding how these compounds modulate oxidative stress and related signaling pathways.MethodsBiospecific cell extraction and ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) were employed to screen and identify these compounds. Protective effects were assessed by measuring cell viability, malondialdehyde (MDA), and superoxide dismutase (SOD) levels, along with detecting intracellular reactive oxygen species (ROS) using 2, 7-dichlorodihydrofluorescein diacetate (DCFH-DA) and dihydroethidine (DHE) probes. Real-time qPCR and Western blotting were used for mRNA and protein level analysis.ResultsTwo novel active compounds, Kuwanon H and Morusin, and the known Kuwanon G, were identified. They significantly reduced MDA and ROS levels while increasing SOD activity in ox-LDL-treated HUVECs. Kuwanon H was particularly effective, enhancing nuclear factor erythroid 2-related factor 2 (Nrf-2) activity and upregulating its target genes Heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1 (NQO-1).ConclusionIn conclusion, Kuwanon H, Morusin, and Kuwanon G effectively protected HUVECs from ox-LDL-induced oxidative injury, with Kuwanon H showing the strongest protective effects via the Nrf-2/HO-1 signaling pathway. These compounds hold potential in treating atherosclerosis and related oxidative stress diseases.Graphical

APPLICATION OF IONIZING RADIATION IN THE PRESERVATION AND CONSERVATION OF TAXIDERMIED ANIMAL SKINS IN NATURAL HISTORY MUSEUMS<i></i>

The great interest in the development of research involving ionizing radiation aims to significantly increase the conservation of the skins of taxidermized animals, both for scientific collections and on display, causing their infection and disinfestation, without altering their originality, reducing the use of chemical products, presenting a safe and efficient technology. The preservation of taxidermied mammals has been widely used for educational, scientific and Museum display purposes. However, prolonged exposure to environmental factors or the excessive use of chemicals to store these materials in the collection can affect the integrity of the skin of these animals. In this study, we investigated the effects of gamma radiation on the structure and composition of the skin of taxidermied mammals, with the aim of contributing to a better understanding of conservation processes and the potential risks they may entail. Taxidermy is an animal preservation technique that has been used for centuries, allowing specimens to be arranged in their natural form and/or preserved for scientific studies. Samples of skin from animals from the Brazilian flora were selected, deer, coati, prawn and bison, and these samples were irradiated at doses of 1, 3, 5, 10 and 15 kGy. After gamma irradiation, they were characterized by colorimetry, scanning electron microscopy (SEM), optical microscopy (OM), infrared microscopy (FTIR) and mechanical analysis. The results show that the doses of gamma irradiation that the samples were subjected to did not compromise their physical and chemical integrity. This indicates the possibility of using gamma radiation for disinfestation and disinfection.

The impact of eco-industrial parks on urban haze pollution: evidence from China

Abstract With the green, circular, and low-carbon concept, eco-industrial parks are regarded as key drivers for maximizing environmental and economic benefits. Based on the panel data of 276 cities in China from 2007 to 2018, this paper regards the establishment of eco-industrial parks as a quasi-natural experiment, and employs the difference-in-differences method to test the impact of eco-industrial parks on urban haze pollution. We find that eco-industrial parks significantly reduce urban haze pollution and the conclusion holds with robustness tests. Heterogeneity analysis shows that the effect of eco-industrial parks on haze pollution is more pronounced in eastern and resource-based cities. Finally, mechanism analysis indicates that eco-industrial parks reduce urban haze pollution mainly by promoting technological innovation, upgrading industrial structure, and strengthening urban environmental regulations.

Anchoring of Radially Expandable Microcapsule Robots in Blood Vessels Based on the Anchoring Method in Fan-Shaped Peristaltic Tubes

Radially expandable capsule robots are essential in alleviating thrombosis due to their unique anchoring and expansion capabilities within blood vessels. Despite their potential, research in this area remains limited, highlighting the need for further exploration. This study draws inspiration from the stable anchoring mechanisms observed in fan-shaped peristaltic tubes to establish a robust anchoring resistance model specifically for capsule robots in vascular environments. The research investigates the biomechanical characteristics of blood vessels under expansion conditions, deriving the longitudinal profile equation to better understand these interactions. Based on the established model, various optimization methods are proposed to enhance the anchoring performance of the capsule robots. To validate the model's accuracy, anchoring resistance is tested using a phantom vessel on an experimental platform. By integrating kinematic and mechanical analyses, an inchworm-type expansion force model is developed to evaluate anchoring performance quantitatively, allowing for an in-depth analysis of how design parameters influence anchoring resistance. This provides vital theoretical support for the design and optimization of capsule robots aimed at improving clinical outcomes in thrombotic conditions

Effect of Nitrogen Composition on Band Gap Energy and Photocatalytic Activity of TiO2-N/Zeolite Composite

In this study, the application and performance of TiO2-N/Zeolite composites for MB photodegradation under UV irradiation have been reviewed. To improve the removal performance, the TiO2-N/Zeolite composite was varied based on the concentration ratio of urea to TiO2, where urea is a precursor of nitrogen. UV-Vis DRS tests were also carried out to compare and evaluate differences in band gap energy for each variant, analysis of degradation results and MB removal mechanisms by TiO2-N/Zeolite composites are described in this study. The aim of this research is to determine the effect of the urea to TiO2 concentration ratio (urea:TiO2), on the photocatalytic activity of the TiO2-N/Zeolite composite and also its physical characteristics, namely band gap energy. Thus, as a comparison, TiO2 and TiO2-N were also tested for photocatalytic activity and band gap energy physical characteristics. The conclusion obtained from this research is that the smaller the nitrogen composition in the TiO2-N/Zeolite composite, the greater the photocatalytic activity capability in degrading MB, in this case the TiO2-N/Zeolite (1.5) sample has the best photocatalytic activity. The next conclusion is that the higher the nitrogen composition in the TiO2-N/Zeolite composite, the smaller the band gap energy.

Multi-Omics Insights into Regulatory Mechanisms Underlying Differential Deposition of Intramuscular and Abdominal Fat in Chickens

Excessive abdominal fat deposition in chickens disadvantages feed conversion, meat production, and reproductive performance. Intramuscular fat contributes to meat texture, tenderness, and flavor, serving as a vital indicator of overall meat quality. Therefore, a comprehensive analysis of the regulatory mechanisms governing differential deposition of abdominal versus intramuscular fat is essential in breeding higher-quality chickens with ideal fat distribution. This review systematically summarizes the regulatory mechanisms underlying intramuscular and abdominal fat traits at chromatin, genomic, transcriptional, post-transcriptional, translational, and epigenetic-modification scales. Additionally, we summarize the role of non-coding RNAs and protein-coding genes in governing intramuscular and abdominal fat deposition. These insights provide a valuable theoretical foundation for the genetic engineering of high-quality and high-yielding chicken breeds.

Mechanical Modeling and Finite Element Analysis of Typical Compliant Mechanisms Based on Flexible Leaf Springs

In recent years, compliant mechanisms have been widely applied across various fields due to their unique functionalities and superior attributes, demonstrating tremendous development potential and playing critical roles in several key areas. However, the distinct motion characteristics of compliant mechanisms necessitate the consideration of numerous factors in practical applications, making foundational theoretical formulas particularly important. The theoretical derivation of compliant mechanisms forms the essential basis for advancing their development and applications. This study focuses on several typical compliant mechanisms, deriving theoretical formulas by establishing mechanical models and conducting finite element simulations. The simulation errors, all within 1.5%, validate the accuracy of these formulas, thereby providing a theoretical foundation for the further application and development of compliant mechanisms.

A Single-Loop Method for Time-Variant Reliability Sensitivity Analysis of Motion Mechanisms Using Bayes’ Theorem

Abstract Time-variant reliability sensitivity (TRS) analysis can measure the effect of input factors on the structure/mechanism failure. The traditional method for TRS analysis employs a nested sampling procedure, with computational cost depending on the number of input factors. To address the above weaknesses, a single-loop method is developed for TRS analysis. Based on Bayes’ theorem, the sensitivity measure is derived and expressed by the difference between the probability density function (PDF) and the failure-conditional PDF. This derivation allows for TRS analysis to be performed with just one set of samples, where the computational complexity does not depend on the number of inputs. Then, the procedures for Monte Carlo simulation (MCS) are listed based on the innovative estimation of the sensitivity index. Three examples involving numerical and engineering problems are employed to validate the proposed strategy, with the direct MCS introduced for comparison. The results reveal that the proposed strategy provides satisfactory TRS analysis while significantly saving computational resources.

Current Status, Challenges, and Prospects of Combining Immune Checkpoint Inhibitors and Chemotherapy in Non-Small Cell Lung Cancer Treatment

In recent years, significant advancements have been made in the use of immune checkpoint inhibitors (ICIs) for treating non-small cell lung cancer (NSCLC). Nevertheless, their efficacy as monotherapy remains limited in certain patient populations, especially in patients with low levels of PD-L1 expression. The combination of ICIs with chemotherapy has gradually emerged as a novel strategy, aiming to leverage the immune-enhancing effects of chemotherapy to synergize with ICIs. This review provides a comprehensive analysis of the synergistic mechanisms, clinical trial outcomes, safety and toxicity issues, resistance challenges, and future directions of ICI-chemotherapy combination therapy for NSCLC. Clinical evidence suggests that this combination notably extends progression-free survival (PFS) and overall survival (OS), demonstrating promising efficacy, particularly in advanced squamous NSCLC patients with low PD-L1 levels. By inducing immune enhancement through chemotherapy and activating immune responses via ICIs, this combined approach effectively overcomes the limitations of single-agent therapies. Despite a range of challenges, this immunotherapy combination offers renewed hope for improving treatment outcomes in NSCLC patients.

Synthesis and Characterization of DOPO Modified Tetraglycidyl Eugenol Cyclic Siloxane Resins Cured with Tannic Acid

AbstractIn this work, a tetra glycidyl eugenol cyclic siloxane resin (TGED4) is synthesized, then further modified with 9,10‐dihydro‐9‐oxa‐10‐phosphaphenathrene‐10‐oxide (DOPO) to produce Si and P epoxy resins. After blending with diglycidyl ether of bisphenol A (DGEBA) and curing with tannic acid (TA), high performance, fire‐retardant polymer networks are created. Near infrared spectroscopy (NIR) confirms the networks are highly cured and have low extractable content, while dynamic mechanical thermal analysis (DMTA) displays a lower Tg and heterogeneous network with increasing DOPO. The networks display a maximum improvement in flexural modulus, strength, and strain to failure of 20.6%, 55.5%, and 78.8% respectively, and at 65.4 MPa strength and 2.8 GPa modulus are comparable to high‐performance networks. Thermogravimetric analysis (TGA) shows that increasing P reduces thermal stability, but contributes to higher char yield despite lower Si. The fire retardancy improve markedly measured via limiting oxygen index (LOI), increasing from 26.5% to a maximum of 35.5%, while V‐0 behavior is readily achieved at the lowest DOPO content. Cone colorimetry further reduces peak heat release rate (PHHR) and total heat release rate (THHR) by 28% and 42%. This work presents hybrid bio‐derived epoxy resins with excellent fire retardancy and good mechanical properties.

From the end to the beginning: Obtaining and evaluation of flexible PVC produced via chemical recycling of post-consumer PET

Di(2-ethylhexyl) terephthalate (DEHTP) is a promising substitute for dioctyl phthalate (DOP, banned in certain countries) as a polyvinyl chloride (PVC) plasticizer. This research endeavors to present findings about the synthesis of DEHTP through the depolymerization of polyethylene terephthalate (PET) with 2-ethyl-1-hexanol, the production and assessment of PVC formulated with this plasticizer, and a comparative analysis with PVC compounded using commercial plasticizers (DOP and DEHTP). Approximately 200 post-consumer PET bottles underwent chemical recycling under various conditions, leading to complete depolymerization (99%) following a six-hour reaction at 300°C. The plasticizers were characterized by infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, and gas chromatography coupled to mass spectrometry. The flexible PVCs were tensile and hardness tested and submitted to dynamic mechanical and thermogravimetric analyses. The resulting plasticizer exhibited properties analogous to commercial DEHTP, producing flexible PVC with even better properties. For instance, the activation energy of the dehydrochlorination reaction of the flexible PVC produced with DHETP from depolymerization was 3.3% to 16.2% higher than those produced with commercial plasticizers.

Interaction between nitrate and trichloroethene bioreduction in mixed anaerobic cultures

Bioremediation of trichloroethene (TCE)-contaminated sites often leads to groundwater acidification, while nitrate-polluted sites tend to generate alkalization. TCE and nitrate often coexist at contaminated sites; however, the pH variation caused by nitrate self-alkalization and TCE self-acidification and how these processes affect nitrate reduction and reductive dichlorination, have not been studied. This study investigated the interaction between nitrate and TCE, two common groundwater co-contaminants, during bioreduction in serum bottles containing synthetic mineral salt media and microbial consortia. Our results showed that TCE concentrations up to 0.3 mM stimulated nitrate reduction, while the effect of nitrate on TCE reductive dechlorination was more complex. Nitrate primarily inhibited the reduction of TCE to dichloroethene (DCE) but enhanced the reduction of vinyl chloride (VC) to ethene. Mechanistic analysis suggested that this inhibition was due to the thermodynamic favorability of nitrate reduction over TCE reduction, while the promotion of VC reduction was linked to pH stabilization via self-alkalization. As the initial nitrate concentration increased from 0 to 3 mM, the relative abundance of putatively denitrifying genera, such as Petrimonas and Trichlorobacter, increased. However, the abundance of fermentative Clostridium sharply declined from 31.11 to 1.51%, indicating strong nitrate inhibition. Additionally, the relative abundance of Dehalococcoides, a genus capable of reducing TCE to ethene, slightly increased from 23.91 to 24.26% at nitrate concentrations up to 0.3 mM but decreased to 18.65% as the nitrate concentration increased to 3 mM, suggesting that Dehalococcoides exhibits a degree of tolerance to high nitrate concentrations under specific conditions. Overall, our findings highlight the potential for simultaneous reduction of TCE and nitrate, even at elevated concentrations, facilitated by self-regulating pH control in anaerobic mixed dechlorinating consortia. This study provides novel insights into bioremediation strategies for addressing co-contaminated sites.

Global Trends and Collaborative Models in Manipulative Therapy for Low Back Pain: A Bibliometric and Academic Network Analysis

Background Low back pain (LBP) is a prevalent condition that significantly affects work productivity and quality of life. Despite advancements in treatment, LBP continues to pose a global health challenge, with increasing research on manipulative therapy as a non-invasive treatment option. This study aims to provide a comprehensive bibliometric analysis of global research trends in manipulative therapy for LBP. Summary This study utilized the Web of Science Core Collection database to analyze global research dynamics on manipulative therapy for LBP from 1998 to 2023. A total of 2,879 articles were identified and analyzed using CiteSpace software, revealing key research trends, leading countries, and influential contributors. The analysis demonstrated that research on manipulative therapy for LBP has been steadily increasing, particularly between 2019 and 2021. The United States, the Netherlands, and Denmark were among the leading countries in this field. Core research concepts identified through keyword co-occurrence analysis include "low back pain," "manipulative therapy," and "spinal manipulation." Key Messages Manipulative therapy for LBP is a growing field with increasing global interest, particularly between 2019 and 2021. The United States, Netherlands, and Denmark are leading contributors to the research, with notable academic collaborations. Future research should focus on comparative treatment effectiveness, safety assessments, and mechanistic analyses to further validate the role of manipulative therapy in LBP management.

Does ESG Performance Enhance Corporate Green Technological Innovation? Micro Evidence from Chinese-Listed Companies

This study investigates the impact of Environmental, Social, and Governance (ESG) performance on the green technological innovation (GTI) of Chinese A-share-listed companies, using data from 2009 to 2022. The findings indicate that strong ESG performance significantly enhances GTI, with this effect being more pronounced in state-owned firms and non-high-tech sectors, demonstrating heterogeneity across firm types. Mechanism analysis reveals that ESG performance facilitates GTI by mitigating financing constraints and boosting R&D investments. Moreover, the study identifies a non-linear relationship, wherein the effect of ESG on GTI varies with firm size and environmental regulation intensity, as confirmed through a threshold model. This study not only deepens the theoretical framework linking corporate ESG performance with GTI but also uncovers the practical mechanisms through which ESG performance drives GTI, providing both practical insights and theoretical foundations for governments to formulate corporate green transition policies.

The Effectiveness and Mechanisms of China’s Grain Support Policies in Relation to Grain Yield—An Evaluation of a Wide Range of Policies

Objective evaluation and in-depth systematic analysis of the effectiveness of implementing a grain support policy series represent an important entry point for improving incentives to grow food, improving grain production support and protection systems, and guaranteeing national food security. Thus, we collected and organized grain support policies during the study period according to the government work reports of 31 provinces in China from 2001 to 2022 and applied a two-way fixed-effects model based on the variables constructed using textual analysis to further explore the effects of a range of grain support policies on grain production gains. The conclusions are as follows: (1) grain support policies significantly contributed to an increase in grain production; (2) grain production gains from grain support policies are more pronounced in less industrialized and disaster-affected areas; (3) a mechanism analysis showed that grain support policies enhanced grain production by expanding the scale of food cultivation, upgrading agricultural mechanization, and strengthening soil erosion control; and (4) further analysis showed that grain support policies increased pesticide use. These conclusions are of great significance for improving grain production support and protection systems, enhancing incentives for farmers to grow food and for local governments to control food, and achieving the goal of food security.