Artiles
Article
14 November 2024Hardness-Porosity-Grain Size Interrelationship in Conventionally Sintered 3 mol% Yttria Stabilized Zirconia
Considerable research has been done in the past on expensive, <50 nm particle size 3 mol% yttria-stabilized zirconia (3YSZ) using advanced sintering techniques. However, insights are still needed to reveal which factors among grain size and porosity, when both are changing simultaneously, more strongly control the hardness of conventionally sintered, relatively coarse, 250 nm 3YSZ powder, which can be used to make large industrial engineering ceramic parts at a lower cost. This investigation showed that elevating the sintering temperature from 1500 °C to 1650 °C increased the Rockwell hardness from 49.4 HRA to 86.0 HRA, which was concomitant with an increase in grain size and bulk density. A pseudo-inverse Hall-Petch relationship between hardness and grain size was observed given by H (in HRA) = 153.1 − 69.2/$$\small\sqrt{(\mathrm{grain}\,\mathrm{size})}$$ with a somewhat low R2 of 0.95, which was mainly due to the porosity being an additional important variable. Compared to grain size, the impact of open pore fraction (P) on hardness was stronger, inferred from a higher R2 of 0.99 while fitting the data into the well-known exponential decay equation, H = 92.9 exp(−11.1P). Finally, it was observed that the 3YSZ conventionally sintered at 1650 °C for 2 h had 0.8% open porosity, 6.08 g/cm3 bulk density, 960 nm grain size and consisted of only tetragonal ZrO2.
Review
13 November 2024Recent Advances in Developing Aldehyde-Accumulating Microbes and Future Perspective of Biosynthetic Applications
Aldehydes are a class of compounds that contain carbonyl groups in their side chains and are widely used in industries such as fragrances, flavoring compounds, and pharmaceutical intermediates. In recent years, there has been a substantial rise in the application of microbial synthesis to generate aldehyde compounds and their derivatives. This review will conduct an in-depth analysis of the literature related to the manipulation of microorganisms for aldehyde accumulation and the subsequent generation of aldehyde-derived products using metabolic engineering and synthetic biology principles. Furthermore, the review further highlights the prospects and future potential of employing these aldehyde-accumulating microorganisms to synthesize a diverse range of value-added chemicals.
Article
11 November 2024Rural Local Government Institutional Sustainability Programs and Plans in Cascadia: A Comparative Analysis
This research provides a comparative analysis of institutional sustainability programs in small and rural communities across British Columbia, Oregon, and Washington. The study reveals significant regional differences in the adoption of sustainability initiatives, with Oregon consistently leading in the implementation of various programs such as grant writing, conflict resolution, and e-government. The analysis identifies key factors influencing program adoption, including population growth, economic stability, and remoteness. Communities experiencing significant population growth and financial stability are more likely to adopt multiple sustainability programs, while remoteness and economic challenges, such as inflation, act as barriers. The study underscores the importance of regional context and local conditions in shaping the sustainability efforts of rural communities.
Article
07 November 2024Fully- and Partially- Distributed Adaptive Consensus of Second-Order Multi-Agent Systems Using Only Relative Position Measurements
In this paper, the distributed leader-follower consensus of a group of agents with second-order dynamics under the undirected graph communication topology is studied. The main objective of this study is to solve a major practical multi-agent problem in which the acceleration of the leader is not communicated to each follower. In contrast, the follower agents include some unknown dynamics in their intrinsic structure. By assuming a linear regression structure for leader acceleration and agent’s unknown dynamics, Lyapunov-based adaptive control algorithms are devised to control the network of agents in the presence of the communication loss and modeling uncertainties. The presented study describes two multi-agent control strategies called fully-distributed adaptive control (FDAC) and partially-distributed adaptive control (PDAC) systems in the first method, the followers do not have any a priori information about the communication graph, while in the second method, some information about the eigenvalues of the communication graph is available. The mathematical manipulations required to prove the stability of the FDAC and PDAC methods are presented. Finally, illustrative simulations are conducted to render the proposed algorithms’ merits and efficiencies.
Article
04 November 2024Exploring the Potential Relationship between Gut Microbiome Metabolites and Idiopathic Pulmonary Fibrosis via Network Pharmacology Study
Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic lung disease with a poor prognosis. Previous research has revealed that the gut microbiota is associated with human health and immunity, and it interacts with the lung through the “gut-lung axis”. This study explores the potential relationship between Gut Microbiome Metabolites and Idiopathic pulmonary fibrosis via Network Pharmacology Study. The metabolites from gut microbiota were retrieved from the gutMGene database, and gene targets for these metabolites were obtained from previous studies. Gene targets of IPF were obtained from public databases (DisGeNET, OMIM). Subsequently, following the identification of shared targets, IL6 was determined as the core target through protein-protein interaction analysis. Then, a microbiota-metabolite-target-signaling pathway network (MMTS) was constructed using Cytoscape 3.10, and targets with low expression in the lungs and intestines were deleted. The MMTS network revealed that three short-chain fatty acids—acetate, butyrate, propionate, and a flavonoid compound called equol—are IL6-related metabolites. Then, we performed a molecular docking test (MDT) using CB-Dock2 to validate the affinity between core targets and metabolites. MDT confirmed that equol produced by the conversion of isoflavones from Lactobacillus paracasei JS1 was more stable in binding to IL6 than the other three short-chain fatty acids, thereby affecting multiple signaling pathways and influencing the progression of IPF. Finally, we validated this hypothesis through in vitro cell culture experiments, further confirming the effect of Equol.
Article
04 November 2024Diversity and Meta-Analysis of Microbial Differential Abundance in Nasal Metatranscriptomic Profiles of Asthma
Asthma affects millions worldwide and involves complex genetic, immunological, and environmental factors. The nasal microbiome is increasingly recognized for its role in asthma development, but inconsistent results and small sample sizes have limited a clear understanding. We aimed to clarify the nasal microbiome’s role in asthma using large datasets and meta-transcriptomic analysis. RNA-seq data was analyzed from two large public studies: GALA II (694 children of Puerto Rican heritage; 441 asthmatics, 253 controls) and CAAPA (562 individuals of African ancestry; 265 asthmatics, 297 controls). After quality control and host read removal, microbial reads were annotated using Kraken2. α and β diversity analyses compared microbial diversity between asthmatic and control groups. Differential abundance analysis was conducted separately, controlling for age and sex, with results combined via meta-analysis. We found that asthmatic patients exhibited significantly higher α diversity indices (Shannon, Berger-Parker, Inverse Simpson, Fisher’s) in nasal microbiota compared to controls in GALA II, with similar trends in CAAPA. β diversity analysis showed significant differences in microbial composition in GALA II data. Differential abundance analysis identified 20 species in GALA II and 9 species in CAAPA significantly associated with asthma. Meta-analysis revealed 11 species significantly associated with asthma, including Mycobacterium_tuberculosis. Our study demonstrates increased nasal microbiome α diversity in asthmatic patients and identifies specific microbial species associated with asthma risk. These findings enhance understanding of asthma pathogenesis from the nasal microbiome perspective and may inform future research and therapeutic strategies.
Article
04 November 2024Understanding Rural Consumer Credit Demand: Insights from China’s Household Income and Asset Structures
China’s ongoing supply-side structural reforms and the government’s strategic focus on rural revitalization catalyze a significant transformation in rural landscapes. The steady rise in rural residents’ incomes and assets, along with gradual improvements in household quality of life, is unlocking significant potential for growth and upgrades in the rural consumer market.This evolution necessitates a more diversified and sophisticated approach to financial services that is more inclusive and widespread. Despite the challenges, such as an aging population and imperfect credit systems that have limited the quality and precision of rural financial services, the analysis of household income and asset structures is vital for understanding consumption patterns and enhancing the economic vitality of rural households. Our study, based on the 2019 China Household Finance Survey data of 11,386 households and employing the Heckman two-stage model, finds that the proportions of income components and financial assets, moving in opposite directions, significantly influence the amount of consumer credit demanded, while other asset types, such as real estate, show no significant effect. The examination of income and asset diversity through the Herfindahl-Hirschman Index (HHI) demonstrates varying impacts of income and asset structures on credit demand, depending on the concentration levels of income and assets. Additionally, our analysis of heterogeneity based on the age of the household head and geographic region highlights the diverse influences on the amount of consumer credit demand, underscoring the importance of tailoring financial products and policies to meet the specific needs of rural households. These findings shed light on these dynamics and inform financial service innovations that align with the needs of rural consumers, thereby supporting the broader objectives of rural economic development and the achievement of China’s rural revitalization strategies.
Article
01 November 2024The Agricultural Land Use Changes in Metropolitan Areas: A Case Study in Italy
In recent decades, countries have experienced a widespread increase in population that has resulted in unorganized urban sprawl, problems with land use change and related threats to natural resources. On the other hand, this led to converting agricultural areas into urban spaces. This work aims to analyze land use changes in the metropolitan area of Rome, which has experienced significant urbanization in rural areas. In this context, the agricultural sector’s contribution to the economic growth of peri-urban areas in the metropolitan area of Rome was verified. After showing the extent of agricultural land consumption, an economic evaluation of land use was provided through the analysis of the evolution of urban and peri-urban agriculture in Rome. The analysis was performed using the Italian FADN data for 2008–2020 and a set of structural and economic–financial indicators. Furthermore, the study analyzes the relationship between farm performance and agricultural resources, farmer demographics, and farm size. The analysis reveals that farms are mainly specialized in arable land and herbivores and are conducted prevalently by men with a high school education level and aged between 40 and 65 years. The economic results also show a good performance; however, they are yearly differentiated. Only a few farms resort to other gainful activities to increase the income produced. Therefore, a greater diversification of agricultural activities is desirable. The research provides interesting insights to stakeholders on the public support that needs to be designed and implemented to favor the survival of farms in rural areas.
Article
01 November 2024Alkaline Modified Coir and Unmodified Hemp Fiber Reinforced Epoxy Based Composite for Automotive Application
The growing demand for sustainable materials in the automotive industry has prompted research into natural fiber-reinforced composites. To reduce carbon footprints and enhance product sustainability, the sectors increasingly focus on renewable and biodegradable materials. Composites made from natural fibers, such as coir and hemp, offer a promising solution for creating lightweight, high-performance components with a reduced environmental impact.In this study, an experimental investigation was conducted to examine the impact of single and hybrid and treated and untreated fibers, on the properties of epoxy-based composites. Untreated hemp fiber with treated Coir fiber was used for the research. The composites were fabricated through the open mould hand lay-up technique. Samples were prepared by randomly dispersing the fibers in the epoxy matrix before pouring them into the respective moulds prepared according to ASTM standards. Tensile, impact, and hardness tests were conducted on the cured samples to determine their mechanical properties, while a scanning electron microscope was used to evaluate the fractured surface. Water absorption tendencies were also determined. The results showed that the sample denoted as 5CF wt.% had the best property combination with tensile strength (32.4 MPa), tensile modulus (11.9 GPa), flexural strength (167.0 MPa), and impact strength (46.8 kJ/mm2). It was discovered that hemp fiber-based composites were not enhanced properly due to lack of fiber surface modifications. Though optimum results were obtained from treated coir fiber-based single/distinct composite, untreated hemp fiber was discovered to aid some flexural modulus and hardness properties in the hybrid composite based on the best results obtained in its distinct-based composite. Therefore, untreated hemp fiber can be used in hybrid form with treated coir fiber where one of the fibers is scarce or when fiber surface medication is difficult to achieve. Thus, the results showed that 5CH-based composites are the most suitable composition for automotive components development where high-mechanical properties are essential.
Review
01 November 2024Waste Resin Derived Carbon Materials for Sodium-Ion Batteries
As the environmental issues caused by waste resin become increasingly severe, there is an urgent need to develop ways to handle it in a high-value and harmless manner. Turning waste resin into functional carbon materials is a realizable and promising scheme, which could be a trigger to carry forward emerging sustainable battery technologies and applications. However, there are few review articles about the basics and research progress of the waste resin derived carbon materials for sodium-ion batteries. This review article provides a brief overview mainly about resin recycling and the potential usage of the resultant carbon materials for sodium-ion batteries. Specifically, we show the potential improvements in existing research, focusing on utilization of the waste as well as the significance of new routes for resin recycling. This work offers insights for the design of sustainable carbon materials for battery systems.
