bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of the Mechanical Recycling of Phenolic Resins for Household Appliances
Authors: Valentini Francesco , Rigotti Daniele , Saletti Matteo , Beccaro Alberto , Pasquardini Laura , Pegoretti Alessandro , Dorigato Andrea
Published: December 2024

In light of the significant impact of climate change, it is imperative to identify effective solutions to reduce the environmental burdens of industrial production and to promote recycling strategies also for thermosetting polymers. In this work, the mechanical recycling of phenolic resins, obtained from industrial production scrap of plastic knobs for household appliances, was optimized. The feasibility of a partial substitution of virgin materials with recycled ones was investigated both at a laboratory and industrial scale. Finally, the environmental benefits arising from the use of recycled material were quantified through a life cycle assessment (LCA). The results of laboratory characterization demonstrated that the thermal properties of the phenolic resins were not influenced by the presence of recycled material, and the mechanical performances were not significantly impaired up to a recycled content of 30 wt%. The industrial production trials demonstrated the feasibility of replacing up to 15 wt% of virgin material without any influence on the aesthetical features of the produced components. Finally, LCA of industrially produced knobs highlighted a limited benefit of virgin material substitution in the case of novolac chromium-plated samples, while an overall environmental impact reduction of around 7–10% was detected in the case of resol-based materials.
Research on Interlayer Toughening and Damage Detection of Laser-Induced Graphene and Short Kevlar Fibers Aramid Fiber/Epoxy Resin Composites
Authors: Wang Baolai , Tian Weidong , Wang Chao , Wang Qi
Published: December 2024

The poor interlaminar fracture toughness is a critical limiting factor for the structural applications of aramid fiber/epoxy resin composites. This study investigates the effects of laser-induced graphene (LIG) and short Kevlar fibers on the interfacial toughness and damage detection of aramid composite materials. Mode II tests and tensile tests were conducted to evaluate mechanical properties and damage detection using the piezoresistive characteristics of LIG. The results indicate that LIG combined with short Kevlar fibers significantly enhances the interfacial toughness of the composites, achieving a 381.60% increase in initial Mode II fracture toughness. Although LIG reduced the tensile strength by 14.02%, the addition of short Kevlar fibers mitigated this effect, preserving the overall mechanical performance. Scanning electron microscopy (SEM) analysis revealed enhanced toughening mechanisms, including increased surface roughness, altered crack propagation paths, and fiber bridging. Additionally, LIG enabled real-time damage monitoring, showing a significant increase in resistance upon delamination or crack propagation and a marked increase in resistance upon the tensile fracture. This research indicates that the synergistic effects of LIG and short Kevlar fibers not only enhance the interlaminar toughness of aramid composites but also provide a novel strategy for effective damage detection in fiber-reinforced materials.
Extraction of Purple Prickly Pear (Opuntia ficus-indica) Mucilage by Microfiltration, Composition, and Physicochemical Characteristics
Authors: Fernández-Martínez María Carmen , Jiménez-Martínez Cristian , Jaime-Fonseca Mónica Rosalía , Alamilla-Beltrán Liliana
Published: December 2024

Mucilages are valuable to the food industry, but the solvents used to extract and concentrate them are detrimental to the environment. Therefore, environmentally friendly technologies that preserve the properties of biopolymers and reduce the use of solvents are being sought. In this work, the mucilage of Opuntia ficus-indica (mesocarp–endocarp) was extracted by two methods: In the first one, the pulp from the mesocarp–endocarp was extracted by ethanol precipitation and centrifugation cycles, then dried at room temperature. For the second, the pulp was processed in a three-step tangential microfiltration process: microfiltration (separation), diafiltration (purification), and concentration. The mucilages obtained differed significantly (p < 0.05) in color, betalains, total sugars, and proteins. The proportions of insoluble and soluble dietary fiber were similar. GC/MS analysis identified seven neutral sugars and a high content of uronic acids (31.3% in the microfiltered mucilage and 47.5% in the ethanol-precipitated mucilage). These show a low degree of esterification, which gives them a polar and hydrophilic character and the possibility of interacting with divalent ions through the carboxylic acid groups, which could form gels stabilized by an egg-box mechanism, with application as a thickening, stabilizing, gelling, or film-forming agent for foods with low sugar content.
Field Crop Evaluation of Polymeric Nanoparticles of Garlic Extract–Chitosan as Biostimulant Seed Nano-Priming in Cereals and Transcriptomic Insights
Authors: Mondéjar-López María , López-Jiménez Alberto José , Gómez-Gómez Lourdes , Ahrazem Oussama , García-Martínez Joaquín Calixto , Niza Enrique
Published: December 2024

Current crop management worldwide is shifting toward the use of environmentally friendly products. With this objective, we developed a new phytosanitary product with biostimulant properties based on the encapsulation of garlic extract at a lower dose (<0.1%) in chitosan nanoparticles as a seed nano-priming agent. In the present study, the morphology of the nanoparticles, their stability under prolonged storage conditions, and their efficacy as a biostimulant are evaluated on cereals in rainfed crops, and the activities were correlated with a transcriptomic analysis. The nanoparticles showed a spherical shape and had a maximum size close to 200 nm with satisfactory stability at 4 °C, reducing the probability of aggregation processes in the nanoparticles. The biostimulant properties of the nano-priming agent were evaluated in a field experiment with wheat, barley, and oat seeds at 30 and 90 days, showing that plants treated with nanoparticles showed significant differences with higher values in root development, leaf length, and total plant weight. Finally, through a RNA-SEQ analysis of the treated wheat seeds, we have confirmed that the nano-treatment showed a higher increases in regard to development, metabolism, and plant response genes compared with untreated seeds.
Bonding Performance of a New Resin Core System with a Low-Polymerization-Shrinkage Monomer to Root Canal Dentin
Authors: Hatayama Takashi , Tabata Tomoko , Kibe Kota , Ikeda Masaomi , Sumi Yasunori , Shimada Yasushi
Published: December 2024

Resin core build-ups following root canal treatment still have many issues. This study evaluated whether a new low-polymerization-shrinkage resin core system (LC2) could address these issues by assessing its bonding performance to root canal dentin using microtensile bond strength tests and gap formation using swept-source optical coherence tomography (SS-OCT). Twenty-four extracted human lower premolars were used for bonding performance tests, while forty-eight sound extracted human wisdom teeth were used for gap observation. Four systems were compared: Luminous Core LC flow (LC1), LC2, MI Core LC flow (MIC), and Filtek Fill & Core (FFC). Cylindrical cavities were prepared, bonded, and filled with resin cores, and gap formation was evaluated. The results showed significant differences in bond strength between the coronal and apical sides: LC1 (coronal: 29.9 ± 3.8 MPa; apical: 12.4 ± 2.0 MPa), LC2 (coronal: 31.2 ± 3.6 MPa; apical: 17.8 ± 3.6 MPa), MIC (coronal: 28.7 ± 3.8 MPa; apical: 8.8 ± 2.1 MPa), and FFC (coronal: 29.0 ± 4.2 MPa; apical: 9.5 ± 1.9 MPa). LC2 exhibited significantly higher bond strength at the apical side compared to the other systems (p < 0.05). Gap formation was significantly reduced in LC2 (10.9 ± 5.0%) and FFC (11.9 ± 5.0%) compared to LC1 (31.8 ± 10.5%) and MIC (32.0 ± 5.6%) (p < 0.05). These findings suggest that LC2 is advantageous for resin core build-ups, particularly in improving adhesion to root canal dentin and reducing gap formation.
Study on the Mechanical and Thermal Properties and Shape Memory Behaviors of Blends of Bio-Based Polybenzoxazine and Polycaprolactone with Different Molecular Weights
Authors: Tiptipakorn Sunan , Chaipakdee Naritsara , Rimdusit Sarawut , Hemvichian Kasinee , Lertsarawut Pattra
Published: December 2024

In this research, blends of bio-based polybenzoxazine (V-fa) and polycaprolactone (PCL) with different molecular weights (Mn) (14,000, 45,000, and 80,000 Da) were prepared with varying PCL content from 10 to 95 wt%. The spectra measured using Fourier Transform Infrared Spectroscopy (FTIR) may indicate the presence of hydrogen bonding between two polymeric components. The thermograms obtained using a Differential Scanning Calorimeter (DSC) and dynamic mechanical analyzer (DMA) exhibited a shift in glass transition temperature (Tg), which indicated partial miscibility between V-fa and PCL. The thermograms obtained using a thermogravimetric analyzer (TGA) revealed that the addition of PCL led to an increase in the maximum decomposition temperature (Tdmax). The tensile strength and modulus decreased with an increase in PCL, thus indicating a decrease in brittleness. Interestingly, only the samples with an Mn of 80,000 Da were bendable. The blends with 80 wt% PCL were revealed to have shape memory behaviors with a shape fixity of approximately 81%. The shape recovery ratio of the blends with 95 wt% PCL was approximately 78%.
Preparation and Characterisation of High-Density Polyethylene/Tannic Acid Composites
Authors: Tarani Evangelia , Tara Myrto , Samiotaki Christina , Zamboulis Alexandra , Chrissafis Konstantinos , Bikiaris Dimitrios N.
Published: December 2024

This research paper highlights the preparation and characterisation of high-density polyethylene (HDPE)/tannic acid (TA) composites, designed to confer antioxidant properties to HDPE, valorising a biobased filler. Indeed, tannic acid is a natural polyphenol, demonstrating, among others, strong antioxidation properties. Using a melt-mixing process, HDPE/TA composites containing various amounts of TA, ranging between 1 and 20 wt%, were prepared, and analyses on their structural, thermal, mechanical, as well as antioxidant properties were conducted. Infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction showed that TA was successfully incorporated into the HDPE matrix. Thermogravimetric analysis evidenced that the onset of thermal degradation decreased, but overall satisfactory stability was observed. The composites exhibited exceptional antioxidant properties, especially the ones with the highest TA content, although it was observed that a high amount of TA had adverse effects on the mechanical performance of the composites.
Bridging the Mackie–Plantinga Debate on Evil with Ibn Arabi’s Metaphysics
Authors: Balci Elif Nur
Published: December 2024

This study examines how Ibn Arabi’s metaphysics can address key challenges in the contemporary philosophical debate on the problem of evil. John Mackie famously argues that the existence of an omnibenevolent and omnipotent God is logically incompatible with the existence of evil, suggesting that theism must relinquish one of these divine attributes to resolve this contradiction. Alvin Plantinga, through his Free Will Defense, demonstrates that no logical contradiction undermines the coherence of the theistic conception of God. Although Mackie concedes this point, he contends that Plantinga’s defense does not sufficiently explain why God permits evil. With the resolution of the logical problem of evil, the evidential problem has gained prominence in the theistic debate, where Plantinga’s defense remains inadequate. While Plantinga invites theists to explore potential theological reasons for God’s allowance of evil, he acknowledges that this approach may not yield strong philosophical results. In contrast, Ibn Arabi’s metaphysical framework offers a more comprehensive solution. By integrating ontology, epistemology, and metaphysics to establish a coherent relationship between God, the universe, and humanity, Ibn Arabi renders Mackie’s logical critique irrelevant. Furthermore, his approach fills the gaps left by Plantinga’s defense, offering a more nuanced understanding of the relationship between God and evil.
Elevation Angle Estimation in a Multipath Environment Using MIMO-OFDM Signals
Authors: Yoon Yeo-Sun
Published: December 2024

It is challenging to estimate the elevation angle of low-altitude targets due to the multipath effect. Various signal processing techniques have been proposed to mitigate these effects, including the use of multi-frequency signals as opposed to single narrowband signals. However, the optimal type of multi-frequency signals and their effective utilization have not been thoroughly explored. Compressive sensing was also proposed as a high-resolution angle estimation method. But, that was conducted with narrowband signals. In this paper, we employ MIMO-OFDM signals along with a block sparse Bayesian learning fast marginalized (BSBL-FM) method. This combination allows for the effective processing of multi-frequency signals and provides high resolution estimates. The MIMO-OFDM approach represents radar signals in a block-sparse matrix form, and the BSBL-FM method leverages this sparsity to achieve high-resolution angle estimates. Simulation results demonstrate that our method can accurately estimate angles at extremely low altitudes where the elevation angle is less than 1 degree.
Assessing the Global Sensitivity of RUSLE Factors: A Case Study of Southern Bahia, Brazil
Authors: François Mathurin , Gordon Camila A. , Costa de Oliveira Ulisses , Rousseau Alain N. , Mariano-Neto Eduardo
Published: December 2024

Global sensitivity analysis (GSA) of the revised universal soil loss equation (RUSLE) factors is in its infancy but is crucial to rank the importance of each factor in terms of its non-linear impact on the soil erosion rate. Hence, the goal of this study was to perform a GSA of each factor of RUSLE for a soil erosion assessment in southern Bahia, Brazil. To meet this goal, three non-linear topographic factor (LS factor) equations alternately implemented in RUSLE, coupled with geographic information system (GIS) software and a variogram analysis of the response surfaces (VARSs), were used. The results showed that the average soil erosion rate in the Pardo River basin was 25.02 t/ha/yr. In addition, the GSA analysis showed that the slope angle which is associated with the LS factor was the most sensitive parameter, followed by the cover management factor (C factor) and the support practices factor (P factor) (CP factors), the specific catchment area (SCA), the sheet erosion (m), the erodibility factor (K factor), the rill (n), and the erosivity factor (R factor). The novelty of this work is that the values of parameters m and n of the LS factor can substantially affect this factor and, thus, the soil loss estimation.
Spatial–Temporal Differentiation and Driving Factors of Vegetation Landscape Pattern in Beijing–Tianjin–Hebei Region Based on the ESTARFM Model
Authors: Wang Yilin , Zhang Ao , Gao Xintong , Zhang Wei , Wang Xiaohong , Jiao Linlin
Published: December 2024

Urbanization and industrialization have led to obvious changes in the ecological environment and landscape pattern in the Beijing–Tianjin–Hebei region. Therefore, it is crucial to clarify the spatial–temporal changes in vegetation cover and its landscape pattern and conduct its analysis with the driving factors for ecological preservation in the Beijing–Tianjin–Hebei region. This study combined AVHRR GIMMS NDVI and MODIS NDVI data based on the ESTARFM model to obtain a high spatial–temporal resolution for vegetation cover; it then analyzed the vegetation cover changes at the type and landscape scales using a landscape index and explored the driving factors of the landscape pattern through principal component analysis. The results show that (1) the vegetation is mainly of medium and higher coverage and is distributed in the northeast, the western part of the Taihang Mountains and the central plains in the study area. From 1985 to 2022, there was no statistically significant difference in the overall change in its coverage. (2) From 1985 to 2022, at the landscape level, the vegetation cover landscape exhibited the following characteristics: increased fragmentation, an increase in the complexity of the landscape shape, a decrease in connectivity, a discrete landscape and a decrease in species diversity. At the type level, the medium vegetation demonstrated the most significant degree of fragmentation. The high-vegetation-cover areas exhibited a more concentrated distribution. Additionally, the low, lower and higher vegetation types displayed an increase in complexity, shape, discreteness and heterogeneity within the landscape. (3) Meanwhile, the principal component analysis showed that the changes in the landscape pattern of vegetation cover were mainly the result of the combined effects of climatic and anthropogenic factors in the Beijing–Tianjin–Hebei region. The human factor played the dominant role; this was followed by larger contributions from climatic factors. In addition to offering pertinent scientific insights for the maximization of the ecological environment and the fostering of regional ecological and sustainable development in the Beijing–Tianjin–Hebei region, the aforementioned analysis and research could serve as the foundation for the sustainable management and planning of vegetation cover.
Grid-Coupled Geothermal and Decentralised Heat Supply Systems in a Holistic Open-Source Simulation Model for 5GDHC Networks
Authors: Völzel Constantin , Lechner Stefan
Published: December 2024

In order to reach climate protection goals at national or international levels, new forms of combined heating and cooling networks with ultra-low network temperatures (5GDHC) are viable alternatives to conventional heating networks. This paper presents a simulation library for 5GDHC networks as sustainable shared energy systems, developed in the object-oriented simulation framework OpenModelica. It comprises sub-models for residential buildings acting as prosumers in the network, with additional roof-mounted thermal systems, dynamic thermo-hydraulic representations of distribution pipes and storage, time-series-based sources for heating and cooling, and weather conditions adjustable to user-specified locations. A detailed insight into an in-house development of a sub-model for horizontal ground heat collectors is given. This sub-model is directly coupled with thermo-hydraulic network simulations. The simulation results of energy balances and energetic efficiencies for an example district are described. Findings from this study show that decentralised roof-mounted solar thermal systems coupled to the network can contribute 21% to the total source heat provided in the network while annual thermal gains from the distribution pipes add up to more than 18% within the described settings. The presented simulation library can support conceptual and advanced planning phases for renewable heating and cooling supply structures based on environmental sources.
Cost Estimation for the Operation and Maintenance of Automated Monitoring and Early-Warning Equipment for Geological Hazards
Authors: Luo Gan , Tao Mingqi , Wu Baohe , Zhang Mingzhi , Zhong Shuai , Li Junfeng , Yang Xiaodi
Published: December 2024

Geological hazards impede regional economy sustainability. To limit their destructive impacts on human life and property, the Chinese government has independently developed automated monitoring and early-warning equipment, which has been deployed in over 250,000 locations nationwide, yielding effective early warnings. The smooth operation of this equipment necessitates substantial human, material, and financial resources for its maintenance. To allocate funds rationally, the Ministry of Finance of China has mandated the urgent establishment of budget standards for the operation and maintenance of automated monitoring and early-warning systems for geological hazards. Addressing the research gap in this area, this study meticulously develops a cost model, subcategorizing operating costs, maintenance costs, and management costs. Addressing the intricate issue of maintenance expenditures, this study ingeniously breaks down routine operations and urgent repairs stipulated in technical standards into personnel, materials, and vehicular needs for each equipment type. Considering the total manpower involved in equipment maintenance, the per-unit maintenance cost is determined. This method allocates costs to individual pieces of equipment, thereby sidestepping the quantification hurdle created by varying types and quantities of monitoring equipment at each monitoring site due to various geological disaster types and magnitudes, and technical personnel’s maintenance responsibility for multiple equipment types in a single operation. Finally, incorporating regional adjustment coefficients, we have formulated theoretical costs for the operation and maintenance of automated monitoring and early-warning equipment for geological hazards. By contrasting theoretical costs with actual project budgets, the error margin is within 2%. Following nationwide consultation, these theoretical costs have been officially endorsed as the budget standard. These standards will lay the groundwork for project budgeting and review, facilitate efficient fund utilization, and ensure the financial sustainability of monitoring and warning systems for geological hazards. Concurrently, this paper bridges the global lack in budget norms for the operation and upkeep of automated geological disaster monitoring systems. The cost calculation model introduced serves as a pivotal reference globally for the evaluation of analogous system’s operations and maintenance expenses.
Artificial Intelligence in Digital Marketing Within the Framework of Sustainable Management
Authors: Gündüzyeli Bora
Published: December 2024

Artificial Intelligence (AI) is not only revolutionizing digital marketing through personalized customer experiences and optimized advertising strategies, but it is also contributing to sustainability initiatives. As AI reshapes digital marketing, its impact on sustainability is becoming increasingly significant. This dynamic highlights the necessity of exploring how AI can be utilized to foster more sustainable marketing practices. This study seeks to answer the pivotal question: “How does AI impact the sustainability of digital marketing?” A systematic literature review was conducted in this study, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework to identify various relevant articles in the areas of sustainability and marketing. Furthermore, this study examines the crucial role of AI in enhancing sustainable business practices, highlighting a significant increase in adoption among enterprises. The findings demonstrate that the effective integration of AI into digital marketing enhances environmental sustainability, supports the attainment of economic sustainability objectives, and contributes positively to social sustainability outcomes. This study contributes to the field by providing a comprehensive analysis of the intersection between AI and sustainable marketing practices and offers valuable insights for marketers, businesses, and policymakers.
Feasibility of Recovering and Recycling Polymer Composites from End-of-Life Marine Renewable Energy Structures: A Review
Authors: Elen Muthu , Kumar Vishal , Fifield Leonard S.
Published: December 2024

Over the last few decades, several marine renewable energy (MRE) technologies, such as wave energy converters (WECs) and current energy converters (CECs), have been developed. As opposed to traditional materials such as metal alloys, the structure of these technologies is made up of polymer and polymer composite materials. Most structures have been made using thermoset polymer composites; however, since thermoset polymer composites are not recyclable and lack sustainability, and with recent innovations in recyclable resins, bio-based resins, and the development of additive manufacturing technologies, thermoplastic polymers are increasingly being used. Nevertheless, the methodologies for identifying end-of-life options and recovering these polymer composites, as well as the recycling and reuse processes for MRE structures, are not well-studied. Specifically, since these MRE structures are subjected to salinity, moisture, varying temperature, biofouling, and corrosion effects depending on their usage, the recyclability after seawater aging and degradation needs to be explored. Hence, this review provides an in-depth review of polymer composites used in marine applications, the hygrothermal aging studies conducted so far to understand the degradation of these materials, and the reuse and recycling methodologies for end-of-life MRE structures, with a particular emphasis on sustainability.
Territorial Production and Resource Structures of Asian Russia: Assessment, Typology, and Zoning
Authors: Batomunkuev Valentin S. , Gomboev Bair O. , Sharaldaev Bayanzhargal B. , Zhamyanov Daba Ts.-D. , Tsybikova Aryuna B. , Badmaev Aldar G. , Zangeeva Natalya R. , Motoshkina Marina A. , Rygzynov Tumun Sh. , Banzaraktcaev Zorikto E. , Lygdenova Aryuna B. , Alekseev Aleksei V. , Ulzetueva Ailana D. , Badmaeva Aryuna S.
Published: December 2024

This article examines the territorial production and resource structures in the territory of Asian Russia, which include natural, economic, and social elements. The objective of this study is to assess, typologize, and zone the territorial production–resource structures. The methodological framework of this study is based on calculating an integral development indicator for the regions of Asian Russia, represented by an Adjusted Net Savings index. This index reflects regional wealth according to the World Bank’s expanded concept of national wealth, which includes three types of capital: “reproducible”, “natural”, and “human”. The study also involves a larger typology of the regions, classifying them based on the predominance of these capital forms through the Analytic Hierarchy Process and the triangular illustration method. Regional clustering within the study area was also conducted through the k-means method using Statistica 12 software. Accordingly, adjusted net savings and sectoral contributions to gross regional product were calculated for the regions in this area. A relationship between regional specialization and the level of genuine savings was identified, forming the basis for the grouping of regions. A total of three groups were distinguished: regions with negative, moderate, and the highest levels of genuine savings within the macroregion. A larger typology using dominant, predominant, and complex functions was also developed. Using data on natural, physical, and human capital in Asian Russia, its regions were clustered, resulting in the identification of five clusters. The territory was then zoned based on the clustering results. A total of eight zones were identified, reflecting the size and balance of the three types of capital (human, physical capital, and productive natural), with regions grouped according to their cluster membership and territorial proximity. The findings can help identify pathways for more sustainable development of this territory amidst evolving natural, economic, social, and geopolitical conditions.
Spatial Heterogeneity and Clustering of County-Level Carbon Emissions in China
Authors: Wang Min , Ma Yunbei
Published: December 2024

At present, China is the world’s largest carbon emitter and has also made significant efforts in energy conservation and emission reduction. This study utilized the EDGAR dataset of remote-sensing image inversion to investigate the spatial heterogeneity and clustering patterns of carbon emissions across 2184 counties in China through a data-driven approach. By analyzing the impact of socioeconomic factors on carbon emissions with the Spatial Clustering Autoregressive Panel (SCARP) model, significant regional variations were uncovered. The results reveal significant differences in carbon emission drivers between resource-dependent regions and economically developed areas. For instance, regions with heavy industries, such as Inner Mongolia and Xinjiang, exhibit higher carbon emissions, underscoring the need for policies focused on industrial restructuring and clean energy adoption. In contrast, economically advanced regions such as the Yangtze River Delta and Pearl River Delta show slower emission growth, indicating the potential for further reductions through green technology innovations and energy efficiency improvements. These findings highlight the necessity of regionally tailored carbon reduction strategies, offering policymakers a precise framework to address the specific socioeconomic and industrial characteristics of different regions in China.
Establishing a Mineral Spectral Library for Hyperspectral Imaging of Ore in Underground Mines—A Case Study of Reiche Zeche, Germany
Authors: Salomidi Avgousta , Benndorf Jörg , Barakos George
Published: December 2024

Hyperspectral imaging has emerged as a powerful tool in mineral exploration and surface mining over the past three decades, with applications ranging from large-scale airborne surveys to close-range ground-based studies. However, related research in underground environments remains limited due to various environmental and technical challenges. This study focuses on establishing a hyperspectral library for the Reiche Zeche underground mine in Freiberg, Germany, thereby enhancing the application of hyperspectral techniques in underground settings. Following standard hyperspectral analysis procedures, samples were collected, hyperspectral data were acquired, and pre-processing and processing of these data were conducted. The analysis reveals distinct spectral profiles that effectively differentiated various geological zones within the mine. The goal was to create a hyperspectral library specific to this mine, setting a precedent for future underground studies and highlighting the potential of hyperspectral imaging techniques in mining operations. The success achieved at Reiche Zeche aims to encourage similar initiatives in other mines, promoting the broader adoption of these advanced techniques in underground environments.
Pathways to Resilient and Sustainable Online Education in the New Normal: Interpreting University Teachers’ Willingness to Use Online Teaching Platforms Consistently
Authors: Zhang Zijian , Lin Yinghao , Wang Xiaoyuan , Zhang Xin
Published: December 2024

In the new normal, online education has become a norm and is considered equally important as traditional face-to-face education. Although online teaching has improved accessibility, reduced management costs, and expanded educational opportunities, there are also some issues, such as whether technology and internet access are widespread and whether the quality of online education is better or worse compared to previous modes. With the rapid development of online education, it is crucial to investigate the key factors influencing university teachers’ continuous usage of online teaching platforms and their working mechanisms, which is of great significance for improving the level of educational informatization and promoting educational modernization. This study mainly explores the continuous usage intention of online teaching platforms by Chinese university teachers under the new normal and its influencing factors, aiming to provide theoretical support and practical insights for improving educational informatization, promoting educational modernization, and designing and optimizing online teaching platforms. This study builds a new theoretical framework based on the technology acceptance model (TAM), UTAUT model, and the theory of planned behavior (TPB). From April to November 2024, 343 questionnaires were collected from Chinese university teachers. Combining structural equation modeling (SEM) and fuzzy-set qualitative comparative analysis (fsQCA), the key factors influencing teachers’ continuous usage of online platforms and their configuration relationships are systematically discussed. Not only are the key factors verified, but the configuration relationships are also revealed, providing deeper insights for universities to design, promote, and optimize online teaching platforms and offering theoretical support and practical guidance for promoting sustainable educational development.
Digital Transformation in SMEs: Pre- and Post-COVID-19 Era: A Comparative Bibliometric Analysis
Authors: Petropoulou Aikaterini , Angelaki Erasmia , Rompogiannakis Ioannis , Passas Ioannis , Garefalakis Alexandros , Thanasas Georgios
Published: December 2024

This paper presents a comparative bibliometric analysis of digital transformation in small and medium enterprises, focusing on before and after the COVID-19 pandemic. Using data from the Scopus database, the study analyzes 1566 articles published between 2001 and 2024, focusing on pre-COVID (2001–2018) and post-COVID (2019–2024). Bibliometric tools, including VOSviewer and Biblioshiny, were employed to conduct performance analysis, scientific mapping, and co-occurrence analyses of keywords and co-authorship. The results demonstrate a substantial increase in research output post-COVID, particularly in areas such as the Internet of Things (IoT), cloud computing, and e-commerce. These technologies have become vital for the survival and competitiveness of SMEs in the post-pandemic world. However, the study also highlights significant challenges, including limited financial resources and a lack of skilled personnel, which have hindered SMEs’ ability to implement digital transformation fully. Government intervention, through financial assistance and strategic support, is identified as crucial in enabling SMEs to overcome these obstacles and successfully navigate the digital era. This analysis contributes to the growing body of literature on SMEs’ digitalization, offering key insights for policymakers, researchers, and businesses aiming to adapt to the evolving digital landscape in a post-pandemic economy.
Identifying Non-Perennial River Reaches: A Hybrid Model Combining WEP-L and Random Forest
Authors: Yuan Kangqi , Chu Junying , Zhou Zuhao , Liu Jiajia , Chen Yuwei , Wang Ying , Tang Zuohuai
Published: December 2024

The proportion of non-perennial rivers within the global river network is increasing, and research on these rivers has significantly grown in recent years due to their important role in water resource management and ecosystems. However, existing identification methods primarily rely on river networks with monitoring data and often overlook the temporal variation in flow, limiting further research and analysis. We propose a novel identification approach that couples the WEP-L model with random forest prediction, based on a comprehensive analysis of the limitations of current methods. Specifically, this method involves simulating river flow and incorporating time-series forecasting to facilitate the identification of non-perennial rivers. This approach also divides non-perennial rivers into significantly seasonal and non-significantly seasonal rivers by incorporating seasonal analysis, providing a theoretical foundation for studying their causes and formulating conservation strategies. Using the Yellow River basin in Gansu province as a case study, the results indicate that the total length of non-perennial rivers is 13,085.67 km, accounting for 42.09% of the region’s river length. The cessation periods of significant seasonal non-perennial rivers are primarily in fall and winter, while flow periods are concentrated in summer. The findings provide valuable guidance for the ecological conservation and sustainable management of non-perennial rivers, both in the Yellow River basin and other regions. The introduction and application of this method are expected to improve the identification and management of non-perennial rivers, contributing to the long-term sustainability of water resources.
Aging in Place in a Depopulated, Mountainous Area: The Role of Hometown-Visiting Family Members in Shimogo, Japan
Authors: Wang Wanqing , Saito Yukihiko
Published: December 2024

In this study, we examined the factors that contribute to successful aging in place in the town of Shimogo, a depopulated mountainous area in Japan, focusing on the interplay between household support types, the performance of daily activities, and the involvement of geographically dispersed family members. A mixed-methods approach was used, combining survey data with multiple correspondence analysis and cluster analysis. The resident household findings reveal significant differences in community engagement and reliance on community support across three household support types: self-help, mutual aid, and combined support. The self-help households demonstrated high self-sufficiency and community participation, while the mutual-aid and combined-support households exhibited greater reliance on family and community resources. An analysis of the activities of out-migrated relatives uncovered diverse engagement profiles, motivated by both providing practical support and strengthening family bonds. The visit frequencies and activity types of the relatives were significantly influenced by both their own characteristics and the levels of self-reliance and community support needs of the resident households. Four distinct relative engagement clusters emerged, reflecting varying levels of support, community involvement, and visit frequency. Our findings underscore the crucial role of both informal (family) and formal (community) support networks in facilitating successful aging in place in rural depopulated areas. Policy implications include strategies supporting both self-reliance and the diverse mechanisms of family- and community-based support to ensure the sustainability of life in these challenging environments.
Correction: Lecusay et al. Caring about and with Imaginary Characters: Early Childhood Playworlds as Sites for Social Sustainability. Sustainability 2022, 14, 5533
Authors: Lecusay Robert , Rainio Anna Pauliina , Ferholt Beth
Published: December 2024

The authors would like to make the following corrections about the published paper [...]
Embracing Virtual Reality in Destination Marketing: A Serial Mediation Model to Investigate the Role of Virtual Tourism Experiences in the Formation of Place Attachment
Authors: Luo Jingjia , Xia Menglong
Published: December 2024

Technological innovation is important for destination marketing organisations (DMOs) in achieving sustainable destination development. However, few studies have considered the marketing potential of emerging immersive technologies in promoting local destinations, as well as their impacts on tourists’ place attachment. Drawing upon cue consistency and place attachment theory, this study established a serial mediation model to examine the impact of sensory information acquired from online virtual tourism experiences, such as visual and auditory cues, on tourists’ place attachment formation during the post-trip stage. The PLS-SEM approach was adopted to analyse the data, which were collected from 408 respondents via an online survey. The results showed that tourists’ sensory information significantly influenced their virtual attachment and sense of presence. Furthermore, tourists’ perceived information and image consistency significantly influenced their place attachment. In addition, the serial mediation effect among sensory information, cue consistency, and place attachment was confirmed. The theoretical and managerial implications are also discussed.
Evolutionary Game Analysis of China–Laos Electric Power Cooperation
Authors: Liu Yaqing , Zhang Lifeng , Hu Yushang , Wang Zanxin
Published: December 2024

Cross-border power cooperation is considered a pathway for optimal regional use of renewable resources and the reduction of carbon emissions. To enhance such cooperation, it is essential to understand the game behaviors of the involved parties. This study applied evolutionary game theory (EGT) and system dynamics (SD) methods to analyze the factors influencing strategic choices and cooperation benefits in the China–Laos electricity cooperation. An EGT model was first developed to examine the interactive behavior of both parties and the stability of strategies. Subsequently, an SD model of EGT was constructed to simulate the evolutionary game process, explore the intrinsic mechanisms of the evolutionary game, and analyze the factors affecting strategy selection. The results show that: (1) the gaming behaviors cannot be ignored in cross-border power cooperation; (2) compared to the cross-border trade scenario, the strategic cooperation will generate more benefits for the parties involved and thus will be selected as the cooperation game evolves; (3) the initial strategy ratio of both parties is crucial, influencing the direction of strategy evolution and the time to reach equilibrium; (4) the choice of system cooperation strategy is affected by the unit profit of electricity trade, input cost, incremental return, trade volume, transaction cost, excess return, fine for agreement violation, and the ratio of benefit allocation, among which the former three are critical.
Sedimentary Environment and Source Analysis of Sedimentary Lithium Deposits in Dezong Mahai Salt Lake, Qaidam Basin
Authors: Ma Yuliang , Qin Xiwei , Pan Tong , Chen Jianzhou , Jiang Ziwen , Ding Chengwang , Zhang Dong , Zhang Fan , Feng Ning , Liu Chenglin , Li Qingkuan , Ren Erfeng
Published: December 2024

Lithium possesses exceptionally high economic and strategic significance. China’s lithium resources rank second globally, predominantly found in salt lake brine. Recently, clay-type lithium deposits have been discovered in the Mahai Salt Lake within the Qaidam Basin, featuring a broad distribution area, stable production layers, and thick strata. This paper investigates the mineral sources and mining circumstances of the clay deposits in the study area through the principal trace elements and Sr and Li isotopes of the clay rocks. The study reveals that the sedimentation of the clay deposits in the study area is mainly semi-brine–brackish water phase sedimentation, formed in a shallow water environment of weak oxidation. A terrigenous source characterizes the clay sediment. The tectonic setting of the study area shares common traits with a continental island arc-active continental margin, and the abundant lithium clay rocks mainly receive contributions of feldspar, amphibole, pyroxene, etc. The primary sediment source of the clay deposits mainly stems from igneous and quartz sediment source areas. The 87Sr/86Sr value indicates that the Sr source of the clay rocks in the study area is the shallow over-pressured brine and Yuka River water, mainly derived from the weathering dissolution of silicate rocks. The δ7Li value indicates that the lithium in the lithium-rich clay rocks mainly originates from the release of lithium from silicate minerals in the surrounding mountain ranges, carried by Yuka River water, and from the supply of lithium from the deep Ca-Cl type water body. The research findings establish a foundation for the future exploration and development of clay-type lithium deposits in salt lake regions.
Theoretical and Experimental Investigation of Thermal Conductivity of Unsaturated Soils Amended with a Sustainable Biochar
Authors: Garg Ankit , Ramineni Sai Krishna Akash , Liu Xuekun , Jiang Mingjie , Satyam Neelima
Published: December 2024

This study investigates the thermal conductivity of unsaturated kaolin soil amended with biochar to promote sustainable geotechnical engineering. Biochar from agricultural waste offers the dual benefits of carbon sequestration and sustainable waste management. Experimental measurements were conducted for kaolin soil with 0% (control) and 10% biochar under varying moisture contents. Peach pit biochar increased thermal conductivity by 2–3% at 30–40% saturation and 40–50% at higher saturation as compared to the bare soil. Reed biochar decreased thermal conductivity by 1–2% at lower saturation but increased it by 55–60% at higher saturation. Applewood biochar increased thermal conductivity by 35–50% at moderate saturation, decreased beyond 50% water content, and had minimal variation at lower saturation. Further, the existing empirical models (such as Kersten and the Johansen model, Wiener’s model, and Mickley’s model) for predicting the thermal conductivity of materials were validated using the measured results of biochar-amended soils. Adding 10% biochar reduces thermal conductivity by 34.8%, and the Haigh model (2012) fits best with high accuracy and lower RMSE values than models such as Kersten and Johansen, which appears to be less reliable in case of biochar-amended soils. With an addition of biochar, the R2 values of the models decreased from a range of 0.8 to 0.9 to a range of 0.4–0.6, indicating the need for better model adaptation. Wiener bounds accurately predicted thermal conductivity at low saturation levels but varied greatly at higher ones. The most variable sample was peach pit biochar, highlighting the need to refine predictive models for material-specific differences. These findings provide a foundation for developing improved predictive models and integrating biochar into sustainable geotechnical and geothermal systems.
Innovative Strategies for Microalgae-Based Bioproduct Extraction in Biorefineries: Current Trends and Future Solutions Integrating Wastewater Treatment
Authors: Hamid Nour Abdurahman , Mokaizh Aiman A. Bin , Alazaiza Motasem Y. D. , Bashir Mohammed J. K. , Mustafa Sara Elkheir , Baarimah Abdullah O.
Published: December 2024

Recently, microalgae have emerged as a promising feedstock for biorefineries, offering significant potential for producing high-value bio-based products in areas such as biofuels, nutraceuticals, and environmental management. This study, therefore, undertook an in-depth bibliometric review of 535 articles out of 736 publications published between 2010 and 2024 and sourced from the Scopus database. With the use of the VOS-viewer software, this work identified the major trends within significant research areas in terms of focus and global collaboration networks that pertain to microalgae-based bioproducts. Also, it explored cutting-edge techniques for bioproduct extraction and processing that are both efficient and eco-friendly. This analysis also showed a remarkable growth in output, with peaks in the year 2022, reflecting an interest in renewable energy and methods of sustainable production. The main keywords identified deal with subject areas such as energy, environmental science, and chemical engineering. The dominant technologies referred to dealing with lipid extraction, bio-crude production, and nutrient recycling. While addressing cost, scale-up, and environmental concerns, there is still a need to improve extraction techniques like ultrasonic treatment, supercritical fluid treatment, and enzymatic treatment. Other emerging areas of research include genetic engineering and integrated biorefinery models, which are expected to provide a roadmap for future advancements in the field. The challenges innate in meeting this through innovation and optimization will be the key to realizing the full potential of microalgae to contribute to the circular bioeconomy.