Mechanical Analysis Research Articles

Digital transformation and supply chain concentration: evidence from China

ABSTRACT Excessive supply chain concentration (SCC) introduces various risks, and the factors contributing to SCC are complex and have been rarely explored. This study examines the economic impact of digital transformation on supply chains by analysing data from China’s A-share listed companies (2010–2021) using regression models. The findings demonstrate that digital transformation significantly reduces supply chain concentration and increases the firms’ influence within the supply chain. The mechanism analysis shows that digital transformation makes firms more attractive to suppliers and customers, eases financing constraints, boosts firm reputation, and reduces SCC. The impact is more pronounced in firms facing higher environmental uncertainty or those positioned upstream in the supply chain. Except for blockchain, all five dimensions of digital transformation help to reduce SCC, thereby improving total factor productivity and economic growth. Digital transformation also creates a spillover effect, raising expectations for digital transformation and productivity among suppliers and customers. These findings have significant implications for understanding digital transformation practices and advancing supply chain management. The conclusions remain robust after various tests, including changes to the measures of variables and controls for reverse causality using lagged treatment and instrumental variables.

From starvation to depression: unveiling the link between the great famine and late-life depression

BackgroundThe Great Famine in China from 1959 to 1961 is recognized as one of the most severe social and public health disasters of the 20th century, with profound long-term impacts on the health of survivors, particularly on their mental health. Early-life malnutrition and psychological trauma are considered to contribute to a range of health issues in adulthood, including depression.ObjectiveThis study aims to explore how the experience of the Chinese Great Famine from 1959 to 1961 affects the risk of depressive symptoms among the elderly. Using a mechanism analysis, the study investigates the roles of social support, socioeconomic status, and intergenerational support in this process.MethodsUsing micro-level individual data from the China Health and Retirement Longitudinal Survey (CHARLS), combined with province-level excess mortality data, this study employs a cohort-based difference-in-differences model to identify the causal effects of the famine experience on depression levels among the elderly.ResultsThe study reveals that experiencing the Great Famine significantly increases the risk of depression among the elderly. This effect is more pronounced among rural residents, those who experienced the famine during adolescence, and in regions less influenced by Confucian culture. The mechanism analysis indicates that diminished social support, lower socioeconomic status, and insufficient intergenerational support are the primary pathways through which the famine experience influences depression levels in the elderly.ConclusionsThe experience of the Great Famine has exerted a long-term and profound impact on the mental health of the elderly in China, particularly in terms of depression. The findings provide new perspectives on understanding the long-term effects of major historical events on health and offer important empirical evidence for the development of mental health intervention policies for the elderly.

The Removal and Mitigation Effects of Biochar on Microplastics in Water and Soils: Application and Mechanism Analysis

Due to their widespread distribution, microplastics (MPs) are endangering the soil ecological environment system, causing water pollution and altering the soil’s physicochemical and microbiological features. Because of its unique pore structure and strong stability, biochar is widely used as an adsorbent. However, the effects of MP–biochar interactions in water and soil environment are still unclear. This review outlines the application and mechanism of biochar as an adsorbent in a water environment for the removal of MPs. Also, biochar serves as remediation material for MPs in soils as it mitigates the adverse effects of MPs on soil properties, enzyme activities and soil microbial community. It was found that woody biochar had the highest yield and was more effective in adsorbing MPs. Further research should focus on the combined effects of biochar and MPs, the environmental risks of biochar, the modification of biochar application of MP-removal technologies, the characterization of MP properties, the remediation of combined contamination of MPs and other pollutants, and the transportation of MPs.

Modeling Drug Responses and Evolutionary Dynamics using Patient-Derived Xenografts Reveals Precision Medicine Strategies for Triple Negative Breast Cancer

Abstract The inter- and intra-tumor heterogeneity of triple negative breast cancers (TNBC), which is reflected in diverse drug responses, interplays with tumor evolution. Here, we developed a preclinical experimental and analytical framework using treatment-naive TNBC patient-derived tumor xenografts (PDTX) to test their predictive value in personalized cancer treatment approaches. Patients and their matched PDTX exhibited concordant drug responses to neoadjuvant therapy using two trial designs and dosing schedules. This platform enabled analysis of non-genetic mechanisms involved in relapse dynamics. Treatment resulted in permanent phenotypic changes with functional and therapeutic consequences. High throughput drug screening methods in ex vivo patient derived tumor xenograft cells (PDTCs) revealed patient-specific drug response changes dependent on first-line therapy. This was validated in vivo, as exemplified by a change in olaparib sensitivity in tumors previously treated with clinically relevant cycles of standard-of-care chemotherapy. In summary, PDTXs provide a robust tool to test patient drug responses and therapeutic regimens and to model evolutionary trajectories. However, high inter-model variability and permanent non-genomic transcriptional changes constrain their use for personalized cancer therapy. This work highlights important considerations associated with preclinical drug response modeling and potential uses of the platform to identify efficacious and preferential sequential therapeutic regimens.

Catalytic Production and Upgrading of Furfural: A Platform Compound

Furfural is a renewable platform compound that can be derived from lignocellulosic biomass. The highly functionalized molecular structure of furfural enables us to prepare a variety of high value-added chemicals, which will help realize biomass high-value utilization, and alleviate energy and environmental problems. This paper reviews the research progress on furfural production and upgrading to C5 chemicals from the catalyst perspective. The emphasis is placed on summarizing and refining the catalytic mechanism and in-depth analysis of available data. Specifically, the reaction mechanism of furfural production and upgrading is summarized firstly from the perspective of reaction pathways and reaction kinetics. Then, the available data are further processed to evaluate the actual reaction efficiency of different catalytic systems from multiple dimensions. Finally, based on statistical analysis, the challenges and opportunities of furfural-based research are proposed.

The impact of internet medical service on rural gender inequality in health opportunity: a cross-sectional study

BackgroundThe increasing popularity of Internet medical service may have alleviated the gender inequality in health opportunity faced by rural women. However, research to ascertain the association between Internet medical service and gender inequality in health opportunity is scarce. This study explored the impact of Internet medical service on gender inequality in health opportunity among rural women and the underlying mechanisms involved.MethodsA multistage stratified cross-sectional survey was conducted across six counties in three provinces in China, yielding 3,108 responses for a 97.13% response rate. The questionnaire was used to collect information on Internet healthcare use, health status, health behaviors, social activities and personal exercise, chronic disease status, and demographic and socio-economic characteristics of the participants. Based on Roemer's theory of equality of opportunity (EOP), we established a decomposition strategy for the fairness gap between genders, which we used for the measurement of the gender inequality in health opportunity Fixed effects models, propensity score matching (PSM), and least absolute shrinkage and selection operator (LASSO) regression were utilized to explore the impact of Internet medical service on rural gender inequality in health opportunity.ResultsOn average, rural women experienced a gender health fairness gap of 1.63. Internet medical service significantly mitigated this inequality (β = -0.0602, P = 0.0002), and this finding remained significant across propensity score matching (PSM) and LASSO regression analyses. Mechanistic analysis revealed that human capital positively moderates this effect (β = -0.0510, P < 0.01), while income (β = 0.0370, P < 0.001) and marital status (β = 0.2039, P < 0.001) have negative moderating effects.ConclusionsBy focusing on gender inequality in the digital era, this study highlights the mitigating role of Internet medical service on gender inequality in health opportunity in rural areas. This study proposes and validates the mechanisms through which Internet medical service alleviates gender inequality in health opportunity, suggesting that human capital amplifies this effect, while high personal income and marital status attenuate this effect. These findings contribute to understanding how the digital age can narrow gender health opportunity equality, providing support for future interventions aimed at promoting health equity and gender equality.

Can urban digital intelligence transformation promote corporate green innovation? Evidence from China

Can urban digital intelligence transformation (DIT) facilitate corporate green innovation (CGI)? This research uses the staggered difference-in-differences (DID) approach to study how urban DIT, represented by the Artificial Intelligence Innovation Development Pilot Zones (AIIDPZs), affects CGI. Regression results indicate that urban DIT promotes both the quantity and quality of CGI. Mechanisms analysis reveals that urban DIT promotes CGI by facilitating digital transformation, increasing firms’ investment in R&D, and facilitating information sharing. Heterogeneity analysis shows that urban DIT has a more significant effect on promoting green innovation in non-SOEs, industries with lower pollution levels, and enterprises in regions with high intellectual property protection (IPP). This study offers new perspectives on the role of urn promoting green development and provides empirical support for policy-making.

Research on the impact and mechanism of digital economy on China’s food production capacity

Enhancing and strengthening food production capacity has always been a top priority in agricultural research, serving as a cornerstone for ensuring national food security and stable economic development. This study, based on panel data spanning from 2011 to 2021 across 30 provinces in China, delves into the mechanism through which the digital economy impacts food production capacity. Employing a double fixed effect model, a mediation effect model, and a panel threshold model, we uncover several key findings: The digital economy significantly boosts food production capacity, with robustness tests affirming the reliability of our results. Mechanism analysis reveals that the digital economy enhances food production capacity by elevating total factor productivity and bolstering agricultural resilience. The threshold effect underscores that urbanization levels exhibit a single-threshold impact, wherein the influence of the digital economy on food production capacity intensifies upon crossing this threshold. Heterogeneity analysis reveals that the digital economy significantly boosts food production capacity in central and primary grain-producing regions, while its impact is comparatively weaker in the eastern and western regions, as well as in non-primary grain-producing areas. In summary, this research sheds light on the pivotal role of the digital economy in augmenting food production capacity, offering valuable insights into regional variations and thresholds in its impact across China.

Capital market liberalization and corporate environmental performance: Evidence from the Shanghai–Hong Kong Stock Connect

The implementation of Shanghai-Hong Kong Stock Connect marks the maturity of China’s capital market, and the effect of the implementation has been the focus of academic attention. Based on this quasi-natural experiment, We select 3248 samples of heavily polluting enterprises listed in China in 2010–2020 to examine the impact of capital market liberalization and on corporate environmental performance.The results show that capital market liberalization significantly improves the environmental performance of heavy polluting enterprises. The results of the heterogeneity analysis indicate that the positive effect varies across firms with different ownership and internal controls. Finally, mechanism analysis results find that capital market liberalization promotes the environmental performance of heavily polluting firms by increasing environmental assets,reducing stock price volatility,and improving the quality of information disclosure.

Experimental Investigations of the Influence of Spent Coffee Grounds Content on PLA Based Composite for 3D Printing

Nowadays Fused Deposition Modeling, a widely utilized additive manufacturing technology, is significantly transforming as modern production processes. Beyond basic uses to it role in sustainability, Fused Deposition Modeling offers processing potential for implanting circular economy by reducing virgin materials consumption and enhance the integration of waste food for sustainable 3D printing. This research paper investigated the production of new composite materials based on spent coffee grounds. In addition, PLA and SCG at various contents (0, 3, 5, 10, and 15 wt%) were dried and premixed, then processed into PLA/SCG composite pellets using twin-screw extrusion. These pellets were successfully converted into filaments and subsequently used for 3D printing. The effect of spent coffee grounds in PLA composites was investigated via physical and mechanical analysis of 3D printed samples. Regarding density measurements, results revealed that adding up to 5 wt% of spent coffee grounds increased the density while further additions led to a decrease which due to the printing parameters such as extrusion temperature and nozzle diameter. Considering the mechanical properties, the Young’s modulus increased once the spent coffee grounds content reached 3 wt% and then decreased. In the other hand, there was no enhancement in tensile strength and elongation at break which corroborating with density measurements. This mainly contributed to the changes in mechanical properties caused by printing parameters. This study demonstrates that coffee waste can be used as a filler in environmentally friendly composites for 3D printing, with a maximum SCG content of 15 wt%. This approach not only promotes the reuse of coffee waste but also reduces the cost of traditional PLA filaments.

Depression in children: Impact of the father companionship and peer relationship

AbstractReasons for the increased incidence of depression in Chinese children remain poorly understood. Therefore, this study explored the influence of paternal companionship and peer relationships on depression in children based on OLS method using data reported by 2498 children from China (children Mage 10.7; 52.1% girls). We found that both variables could alleviate depression among children, but the effect of peer relationships was significantly greater than that of paternal companionship. This conclusion remains robust after considering gender, age and family structure. Heterogeneity studies have found that paternal companionship significantly impact boys, while peer relationships significantly impact girls. Mechanism analysis demonstrated that both factors can indirectly alleviate depression in children by regulating anxiety. Our research results emphasize the importance of increasing paternal companionship and peer relationships to alleviate depression in children.

State‐owned equity participation and corporate green innovation: evidence from Chinese private enterprises

This study examines the influence of state‐owned equity participation on green innovation in private enterprises. Using the data of China's A‐share private listed companies between 2009 and 2021, the paper finds that state‐owned equity participation has a positive impact on corporate green innovation and this finding remains consistent and dependable after conducting a series of robustness tests. In addition, this paper also uncovers that the impact of state‐owned equity participation on corporate green innovation differed across regions, industries, and external corporate governance. The results show that the incentive impact of state‐owned equity participation on green innovation is more pronounced in private enterprises with higher levels of intellectual property protection in the region where they are located, belonging to high‐tech industries and with higher media attention. Further mechanism analysis reveals that state‐owned equity participation enhances corporate green innovation by improving the fulfilment of corporate environmental responsibility and alleviating corporate financing constraints. Overall, this study enriches the research of green innovation influencing factors from the perspective of minority state‐owned equity and can help to inspire governments to make full use of state‐owned equity to promote the green transformation of private enterprises, thus contributing to the sustainable development of the global economy.

The effects of digital economy on manufacturing resource allocation efficiency across Chinese cities: a spatial economic perspective

ABSTRACT The development of digital economy provides significant impacts on spatial distribution of industries. Using microdata from Chinese manufacturing enterprises and adopting a spatial economic perspective, this study reveals that the digital economy exerts non-linear impacts on resource allocation. As the level of urban digital economy improves, the efficiency of manufacturing resource allocation shows an inverted U-shaped trend, and high hierarchy cities exhibit higher critical values. The study finds a positive spatial correlation in manufacturing resource allocation efficiency across cities; however, the growth of digital economy in neighbouring cities may lead to backwash effects and impede local improvements in allocation efficiency. The mechanism analysis indicates that the digital economy primarily affects spatial resource allocation through urban agglomeration economies and diseconomies. Consequently, economic agents and policy makers in cities should consider the dual effects of ‘location optimization’ and ‘transforming the economy from substantial to fictitious’ during digital transformation processes to select optimal development paths and improve allocation efficiency.

Navigating the hydrogen landscape: An analysis of hydrogen support mechanisms in the United States and the EU

AbstractWhilst hydrogen as a substance is not new, the recent surge in interest around hydrogen is prompting new regulatory frameworks and hydrogen strategies to support the uptake of the hydrogen economy. The potential of hydrogen to facilitate the decarbonisation of especially hard‐to‐abate sectors is immense, and various jurisdictions are actively creating regulatory frameworks for hydrogen investments, particularly in their green, clean or low‐carbon forms. This is crucial because hydrogen's environmental impact depends on its production methods. This article explores the United States (US) and the European Union (EU) approaches in implementing measures to support the uptake of hydrogen market. More specifically, it seeks to identify the main similarities and differences of the forerunner jurisdictions' adopted policies. The article focusses on the recent measures proposed or adopted by both jurisdictions, suggesting that their leading positions are becoming more aligned.

Mechanical Property Analyses of Two Types of Steel–Concrete Composite Track Beams

Mechanical Property Analyses of Two Types of Steel–Concrete Composite Track Beams

Heterogeneous Carbonylation of Alcohols on Charge‐Density‐Distinct Mo−Ni Dual Sites Localized at Edge Sulfur Vacancies

AbstractAlcohols carbonylation is of great importance in industry but remains a challenge to abandon the usage of the halide additives and noble metals. Here we report the realization of direct alcohols heterogeneous carbonylation to carbonyl‐containing chemicals, especially in methanol carbonylation, with a remarkable space‐time‐yield (STY) of 4.74 molacetyl/kgcat./h and a durable stability as long as 100 h on Ni@MoS2 catalyst. Mechanistic analysis reveals that the Mo−Ni dual sites localized at edge sulfur vacancies of Ni@MoS2 exhibit distinct charge density, which strongly activate CH3OH to break its C−O bond and non‐dissociatively activate CO. Density functional theory calculations further suggest that the low charge density in Mo−Ni, the Ni site, could significantly lower the barrier for CO migration and nucleophilic attack of methoxy species, and finally leads to the rapid formation of acetyl products. Ni@MoS2 catalyst could also effectively realize the carbonylation of ethanol, n‐propanol and n‐butanol to their acyl products, which may demonstrate its universal application for alcohols carbonylation.

Vitreous tissue cryopreservation using a blood vessel model and cryomacroscopy for scale-up studies: Observations and mathematical modeling

Successful long-term cryobanking of multicellular tissues and organs at deep subzero temperatures calls for the avoidance of ice cryoinjury by reliance upon ice-free cryopreservation techniques. However, the quality of the cryopreserved material is the direct result of its ability to survive a host of harmful mechanisms, chief among which is overcoming the trifecta effects of ice crystallization, toxicity, and mechanical stress. This study aims at exploring improved conditions to scale-up ice-free cryopreservation by combining DP6 as a base cryoprotective agent (CPA) solution with an array of synthetic ice modulators (SIMs). This study is conducted by integrating cryomacroscopy techniques, thermal modeling, solid mechanics analysis, and viability and contractility investigation to correlate physical effects, thermal outcomes, and cryobiology results. As an extension of previous work, this study aims at scale-up of established baseline blood vessel models, while comparing the relative toxicity and vitreous stability of 4 ml and 10 ml samples of DP6 containing either sucrose as a SIM, or the commercial synthetic ice blockers (X1000 and Z1000). Using that established protocol, the addition and removal of DP6+0.6M sucrose and DP6 + 1% X1000 + 1% Z1000 were both well tolerated in rabbit carotid and pig femoral artery models, when assessed for metabolic recovery and contractility. Using cryomacroscopy, it was demonstrated that DP6 + 0.6M sucrose provided a stable vitrification medium under marginal cooling and warming conditions that resulted in >50% survival rate. By contrast, DP6 + 1% X1000 + 1% Z1000 was subject to visible ice formation during cooling under the same thermal conditions, resulting in a significantly lower recovery of ∼20%. Thermal modeling is used in this study to verify the actual cooling and rewarming rates in the specimens, while thermomechanics analysis is used to explain why fractures were observed using cryomacroscopy when the specimens were contained in glass vials but not in plastic vials.

The Impact of COVID-19 on Patterns of Fractures Presenting to Pediatric Emergency Departments.

To examine differences in pediatric fracture prevalence, severity, and mechanisms of injury before and during the COVID-19 pandemic. This is a subanalysis of data from a multicenter, cross-sectional study of all injury-related visits to 40 urban pediatric emergency departments (EDs) for children younger than 18 years occurring January 2019-December 2020. ED visits for injuries including fractures were identified by International Classification of Diseases, Tenth Revision codes. Comparative analyses of patient demographics, fracture prevalence, severity, and mechanisms of injury for March 17, 2019, to December 31, 2019 (pre-COVID), versus March 15, 2020, to December 31, 2020 (during COVID), were performed. Fracture-related visits comprised 21.0% (n = 123,684) of all injury visits (n = 589,083) during the study period. There were 16,190 fewer fracture-related visits (-23.2%) in 2020 than 2019. There were differences in the proportion of fracture-related visits by age (P < 0.0001), with increases in children younger than 5 years and decreases in children 5 to 18 years old. There were higher proportions of visits in 2020 among female patients, White children, non-Hispanic children, and those with private insurance (P < 0.0001, respectively). Patients with fractures in 2020 were more severely injured, with higher proportions of hospitalizations (P < 0.0001), intensive care unit admissions (P < 0.0001), deaths (P = 0.007), and higher injury severity scores (P < 0.0001). Fracture mechanisms shifted to more motor vehicle crashes, bicycles, and firearms in 2020 (P < 0.0001). Despite a decrease in fracture-related visits to urban pediatric EDs during the early COVID-19 pandemic, there was an increase in the proportion of ED visits for children younger than 5 years and higher severity injuries. These findings highlight injury epidemiology pattern shifts that occurred during the pandemic. Identifying higher-risk populations for fracture may help guide targeted education and prevention efforts.

Design of the electrode structure for the dust removal efficiency optimization of electrostatic precipitator

Abstract Air dust pollution prevention and control is a global environmental concern. Electrostatic precipitators (ESPs) play a crucial role in dust pollution control, and its electrode structure significantly affects plasma parameters and the movement of charged dust particles, which in turn influences the dust removal efficiency. This study focuses on optimizing the commonly used wire-plate dust removal device, experimental research is conducted first, revealing that the hole-hole electrode structure of an ESP exhibits higher peak currents at the same voltage compared to both plate-hole and plate-plate electrode configurations. For the removal efficiency of particles with a radius greater than 1 μm, the ESP with a hole-hole electrode structure performs better than those with plate-hole and plate-plate electrode structures. Moreover, the particle collection efficiency is positively correlated with particle radius, larger particles correspond to higher dust removal efficiency. Based on experimental findings, simulations are conducted to provide a deeper analysis and understanding of the dust removal mechanisms of ESPs. This paper primarily utilizes COMSOL Multiphysics numerical simulation software to simulate traditional wire-plate ESPs and a new wire-hole ESP. It explores the multiphysical characteristics of ESPs under different electrode structure configurations, and investigates in depth the impact of electrode structure on dust removal efficiency. The simulation results indicate that compared to flat collecting electrodes, porous collecting electrodes exhibit a significant increase in electric field intensity at the openings, and they have a lower surface charge density than flat plates, thereby reducing reverse corona phenomena. Ion wind affects the internal airflow dynamics of ESPs, thereby influencing their efficiency in capturing fine particulate matter. This negative impact of ion wind can be mitigated by introducing perforations in the collection plates.

Palladium Single Atom-supported Covalent Organic Frameworks for Aqueous-phase Hydrogenative Hydrogenolysis of Aromatic Aldehydes via Hydrogen Heterolysis.

Developing a method for the tandem hydrogenative hydrogenolysis of bio-based furfuryl aldehydes to methylfurans is crucial for synthesizing sustainable biofuels and chemicals; however, it poses a challenge due to the easy hydrogenation of the C=C bond and difficult cleavage of the C-O bond. Herein, a palladium (Pd) single-atom-supported covalent organic framework was fabricated and showed a unique 2,5-dimethylfuran yield of up to 98.2% when reacted with 5-methyl furfuryl aldehyde in an unprecedented water solvent at 30°C. Furthermore, it exhibited excellent catalytic universality while converting various furfuryl-, benzyl-, and heterocyclic aldehydes at room temperature. The analysis of the catalytic mechanism confirmed that H2 was heterolytically activated on the Pd-N pair and triggered the keto-enol tautomerism of the covalent organic frameworks (COFs) host, resulting in H--Pd∙∙∙O-H+ sites. These sites served as novel asymmetric hydrogenation sites for the C=O group and hydrogenolysis sites for the C-OH group through a scarce SN2 mechanism. This study demonstrated remarkable bifunctional catalysis through the H2-induced keto-enol tautomerism of COF catalysts for the atypical preparation of methyl aromatics in a water solvent at room temperature.