bluuebunny/crossref_metadata_2025 huggingface dataset:
Physical-Mechanical Properties of Light Bark Boards Bound with Casein Adhesives
Authors: Urstöger Johannes , Kain Günther , Prändl Felix , Barbu Marius Catalin , Kristak Lubos
Published: September 2023

Based on the background of the limited availability of raw materials in the forestry and timber industry, increased attention applies to sawmill by-products and their potential for future applications. Within the present research, the suitability of a natural binder based on different casein sources, superficially lean curd with different lime ratios, for the production of bark insulation panels from larch bark (Larix decidua) in fraction 12.5–4.0 mm with densities below 500 kg/m³ were discussed and physical and mechanical properties evaluated. In order to obtain a benchmark, control boards bound with powdery casein and urea-formaldehyde resin were fabricated. The evaluation of physical-mechanical characteristics indicated the lean curd panels to be competitive with the references and commercially available insulation materials, whereby higher values could be achieved consistently with a lower lime content of 20% compared to 31%. The best moisture resistance and water absorption were observed with a lime ratio of 31%, whilst thickness swelling and mechanical characteristics were best with a lime content of 20%. Particularly with regard to mechanical properties, panels containing a low proportion of lime in the lean curd blends delivered convincing results, e.g., with an average IB of 0.19 N/mm2, MOR of 1.43 N/mm2 and C of 1.70 N/mm2. In terms of thickness swelling, lean curd adhesives generated unsurpassed values of approximately 11% compared to the casein and urea-formaldehyde references. Additionally, as described in the relevant literature, a considerable influence of density on the mechanical behavior of composite materials was observed. Partly, the lime content significantly influenced the panel properties. The study proved that natural binders based on lean curd and lime are suitable for the production of bark insulation boards and represent a serious alternative to synthetic, oil-based adhesive systems. The results are promising with regard to the market situation due to the availability and pricing of raw materials and technical requirements and demonstrated great potential for further research efforts.
Modeling to Achieve Area Business Continuity Management Implementation via a Fuzzy Cognitive Map
Authors: Meechang Kunruthai , Watanabe Kenji
Published: September 2023

Area business continuity management (Area-BCM) is introduced to enhance sustainable economic growth by building public–private partnerships. It is implemented in pilot industrial zones in disaster-prone regions to tackle problems beyond a single organization’s capacity. The framework emphasizes multiple stakeholders in the decision-making process, but participation and implementation remain major challenges for many practitioners in the search for potential pathways. Therefore, this study presents a model of causal relationships between concepts to achieve the implementation of Area-BCM. To capture expert perceptions and visualize relationships, a fuzzy cognitive map (FCM) is deployed. The use of fuzzy logic facilitates the integration of diverse viewpoints and the representation of ambiguous and complex scenarios. Initially, 28 appropriate concepts were identified by reviewing the literature on practical Area-BCM cases, which were then scrutinized by experts, including eight driving causes, eleven required actions, and nine outcome variables. Subsequently, FCMs were constructed through individual interviews. Since the FCMs had been aggregated, a scenario analysis was performed under five different conditions to evaluate potential strategies. The simulation results present promising concepts that could improve Area-BCM implementation. The findings emphasize that these strategies will have a positive influence when top management is committed, government support is achieved, and workshops exist.
A Collaborative Emergency Drill System for Urban Tunnels Using BIM and an Agent-Based Model
Authors: Yu Gang , Shi Lihua , Wang Yan , Xiong Jing , Jin Yucong
Published: September 2023

With the rapid development of smart cities, the refined management of urban highway tunnels has put forward higher requirements for the emergency disposal ability of operation and maintenance personnel. This paper proposed a collaborative emergency drill system for urban tunnels using building information modeling (BIM) and an agent-based model. The objectives of this paper are as follows: (1) To help address the challenge of multi-person collaborative intelligent drills in complex emergency scenarios, this system constructed an emergency collaborative drill model and a virtual emergency scenario description method based on trait-based objects (TBOs). (2) To help address the challenge of the organization and integration of multi-source heterogeneous data in complex emergency scenarios, the system established an emergency scenario generation method through lightweight BIM data, standard emergency plan documents, and virtual emergency scenario data. The system was successfully applied to the Hongmei South Road Tunnel in Shanghai, China. The feasibility of the proposed system provided practical help for tunnel emergency management and was extended to other urban tunnels in Shanghai.
Declines in the Mekong’s Megadiverse Larval Fish Assemblages: Implications for Sustainable Development
Authors: Chhuoy Samol , Hogan Zeb S. , Chan Bunyeth , Chandra Sudeep , Touch Bunthang , Sor Ratha , Lek Sovan , Ngor Peng Bun
Published: September 2023

Migratory fishes of the Mekong Basin are facing challenges from human-induced stressors. Quantifying the patterns of fish’s early life stages provides important information on spawning seasons, spawning and nursery habitats, reproductive strategies, migration and dispersal patterns, and stock status. However, the ecology of the Mekong larval fishes, including patterns and drivers of larval fish dispersal, is not well understood. Here, we investigate the temporal variability of drifting larval and juvenile fish assemblages in the Cambodian Mekong River and identify their environmental drivers using long-term (10 year) daily fish larval/juvenile data collections. We found that, in the Mekong main channel, the larval and juvenile assemblages were dominated by longitudinal migrants from the families Cyprinidae and Pangasiidae. Peak abundance and richness were found to occur in July and August, respectively. We detected a significant decline in larval and juvenile abundance and richness over the study period. Cross-wavelet analysis revealed that water levels always lead larval abundance, but lag richness. In addition, cross-correlation analysis observed that peak abundance and richness occurred eight weeks and one week, respectively, before the peak water level. We also discovered that species abundance and richness had a strongly positive relationship with maximum water levels. Variation in fish larval and juvenile abundance and richness was also related to total phosphorus, nitrate, alkalinity, and conductivity. Maximum water levels and the key water quality parameters (e.g., phosphorus, nitrate, alkalinity, and conductivity) significantly influence larval and juvenile fish abundance and richness patterns. Therefore, safeguarding natural seasonal flows, especially maximum flows associated with the peak flood pulse, as well as maintaining good water quality, are key to the reproductive success of many migratory fishes and effective dispersal of offspring to the lower floodplain for nursing, rearing, and growth. Clean and unregulated rivers support productive and diverse fisheries.
Managing the COVID-19 Pandemic: Enhancing Sustainable Supply Chain Performance through Management Innovation, Information Processing Capability, Business Model Innovation and Knowledge Management Capability in Pakistan
Authors: Basit Abdul , Wang Laijun , Nazir Samera , Mehmood Saqib , Hussain Iftikhar
Published: September 2023

The advent of the novel coronavirus, also called COVID-19, caused widespread disruptions worldwide. This unprecedented health crisis led to major disruptions in supply chain networks; therefore, innovative strategies and capabilities have the potential to alleviate its impacts. Considering this situation, this study examined how COVID-19 impacted management innovation, the information processing capability, business model innovation, knowledge management capability, and sustainable supply chain performance (SSCP) in Pakistan. To test hypotheses, data were collected from companies in Pakistan engaged in supply chain management or supply chain departments within manufacturing companies, and investigations were carried out employing structural equation modeling. Based on empirical results, COVID-19 outbreaks negatively impacted SSCP, but not management innovation, information processing capability, business model innovation, or the knowledge management capability. Additionally, COVID-19 and SSCP are mediated by management innovation, the processing capability, business model innovation, and the knowledge management capability. By underlining the significance of the resource-based view, dynamic capability, and organizational information processing theories, this research contributes to the body of knowledge on sustainable supply chains. The conceptual model presented in this research may be used in supply chain (SC) and logistics management to reduce COVID-19 disruptions in SC operations and boost profitability during a pandemic.
Cattle Grazing Moderates Greenhouse Gas and Particulate Matter Emissions from California Grassland Wildfires
Authors: Ratcliff Felix , Barry Sheila , Rao Devii , Peterson Rowan , Becchetti Theresa , Kebreab Ermias , Motamed Kaveh , Jung Minju , Mitloehner Frank
Published: September 2023

Between 2010 and 2020, an average of 36,037 hectares of grassland burned in wildfires in California each year, emitting greenhouse gasses (GHGs) and particulate matter (PM). These emissions impact climate and human health. Cattle grazing removes herbaceous fuel through the consumption of forage; however, ruminant digestion also emits GHGs. The purpose of this study was to examine the GHG and PM impact of livestock grazing in grasslands that go on to burn. We used Monte Carlo simulation to determine whether forage consumption by livestock led to reductions in grassland wildfire emissions and whether these reductions outweighed the emissions from the digestion of that forage. We estimate that between 2010 and 2020, an average of 11,590 metric tons (MT) of herbaceous fuel were removed by cattle annually from grasslands in California that went on to burn. This resulted in annual wildfire emission reductions ranging between 0.001 and 0.025 million metric tons (MMT) of CO2 equivalents (CO2e) and between 11 and 314 MT of PM2.5; a small fraction of total GHG and PM emissions from wildfires in California. We also evaluated the change in emissions if burned grasslands in California’s Central and North Coast regions—where removing grazing can lead to the encroachment of shrubs into grasslands—were instead shrublands. If the grasslands that burned in these regions in 2020 had instead been shrublands, we estimate that as much as 0.90 MMT more CO2e and 8448 MT more PM2.5 would have been emitted by wildfires, highlighting the long-term implications of livestock grazing.
Policy and Practice on Inclusive Higher Education in the UK and Kenya: A Theoretical Framework and Recommendations
Authors: Kioupi Vasiliki , Nawire Acquilina Wafula , Musungu Sally , Nzuve Felister , Giannopoulos George
Published: September 2023

This article presents a study that was undertaken as part of a collaborative project between a UK university and a university in Kenya. The study aimed to investigate policies and practices of Inclusion and Inclusive Education in the two universities. Here, we present how Inclusion and Inclusive Education are conceptualized in the two geographical contexts, and review literature on Inclusion, Inclusive Education, disability, race and international/refugee students to develop a theoretical framework that we use to analyze the policies and practices of the two universities in two case studies. Our preliminary findings of this analysis show that Inclusion and Inclusive Education definitions in the two contexts need to be augmented with considerations of identity. We also make recommendations for the two institutions on how they can improve their policies and practices of inclusion, generate new strategies where they are missing or review existing tools and services to evaluate. These recommendations can benefit higher education institutions in the Global North and South.
Exploring the Feasibility of Using Recycled PET Strips with Palm Leaf Ash for Sustainable Soil Stabilization
Authors: Khalid Bisma , Alshawmar Fahad
Published: September 2023

This research paper addresses the urgent environmental concern of waste management by focusing on sustainable consumption by utilizing waste plastic and palm leaves to stabilize soil in geotechnical engineering. The study examines the impact of incorporating recycled polyethylene terephthalate (PET) strips and palm leaf ash (PLA) into clayey sand to enhance its engineering properties. The investigation involved mixing varying proportions of recycled PET strips (10 mm, 20 mm, and 30 mm in length) with clayey sand, ranging from 0% to 2% by weight of the soil with a 0.5% increment for PET strips. Similarly, PLA was mixed with the clayey sand at proportions ranging from 0% to 12% by weight of the soil with a 3% increment. The strength parameters of lateritic soil were analyzed through the execution of unconfined compressive strength (UCS), triaxial, and California bearing ratio (CBR) tests. The optimum mixture was determined to be 2% recycled PET strips with a length of 30 mm and 12% PLA by weight of the soil. This specific combination exhibited significantly improved strength parameters for the lateritic soil, highlighting its potential for sustainable soil stabilization in geotechnical applications.
Evaluation of a Bee-Focused Citizen Science Training Process: Influence of Participants’ Profiles on Learning
Authors: Barbiéri Celso , Koffler Sheina , Leocadio Jailson Nunes , Albertini Bruno , Francoy Tiago Maurício , Saraiva Antonio Mauro , Ghilardi-Lopes Natalia P.
Published: September 2023

In citizen science, training and evaluation are important steps in improving the pedagogical effectiveness of projects. However, evaluating learning outcomes is complex and usually requires multidimensional analysis. In this work, we analyze the influence of the profile of citizen scientists (i.e., gender, age, level of education, educational background, prior experience in beekeeping, and level of contact with nature) on their learning, considering multiple dimensions (i.e., knowledge of the nature of science, self-efficacy, knowledge of scientific process and content, interests, values and priorities, and motivations). Citizen scientists participated in a training course that focused on meliponiculture and citizen science, and they performed a contributory citizen science protocol. The evaluation was based on pre- and post-course questionnaires, (reaching 886 respondents). Learning was observed in all dimensions and, depending on the dimension, profile variables, such as gender, educational level, educational background, and prior experience in meliponiculture were influential. Participants demonstrated high levels of nature connectedness, strong personal norms, pro-environmental behavior(al intention), and high levels of trust in science. The main motivations of the participants were to learn, assist in conservation, and contribute to the production of scientific knowledge about bees. Our findings offer insight into the subsequent steps and future training courses for the #cidadãoasf citizen science project, but they could also be beneficial to other initiatives, indicating the importance of the evaluation of volunteer profiles to guide improvements in a project’s quality.
Participative Policy Design to Manage Droughts and Floods in an Arid Region under Changing Climate Scenarios: The Case of Baja California Sur, Mexico
Authors: Imaz-Lamadrid Miguel Angel , Ivanova-Boncheva Antonina , Flores-López María Z. , Cortés-Martínez Mara Y.
Published: September 2023

Floods can be defined as one of the most frequent and destructive disasters, that cause significant damage to people, while droughts present significant challenges, primarily to the most vulnerable communities. In consequence, not only public policies but the increased participation of communities and other sectors are crucial to manage the risk in the face of both phenomena and contribute to the construction of resilient communities. At the request of the National Water Commission of Mexico (CONAGUA) for the Regional Water Plan (PHR), we designed and applied a methodology based on a web-based consultation in conjunction with digital survey tools to understand the opinion of communities, key participants, and researchers about these phenomena. The workshops were organized in the five municipalities of Baja California Sur. Then, we performed an interdisciplinary analysis that combined hydrological considerations with the most critical social, economic, environmental, and legal components, applying the PESTEL (Political, Economic, Social, Technological, Environmental, and Legal) analysis. The results indicate that there is a clear and widespread awareness that floods and droughts increase the risk to the livelihoods of the population; however, there are deficiencies in different areas, which complicates risk management. Timely distribution of information and the inclusion of communities in mitigation and adaptation proposals would allow the achievement of greater success with efforts to minimize vulnerabilities and increase the resilience of the population in the face of climate extremes. This must be a collaborative work of the entire society: governmental, social, and private stakeholders.
Proposal for a Comprehensive Tool to Measure Smart Cities under the Triple-Helix Model: Capacities Learning, Research, and Development
Authors: Holguín Rengifo Yeimi Xiomara , Herrera Vargas Juan Felipe , Valencia-Arias Alejandro
Published: September 2023

This paper discusses the measurement of smart cities using efficiency indices and proposes a comprehensive tool based on the triple-helix model to assess the learning, research, and development capabilities of smart cities. Existing smart city models are divergent and lack alignment, making it difficult to compare and evaluate cities. The proposed tool aims to contribute to science, technology, and innovation policies by assessing the capabilities of participants in the regional innovation system of smart cities. The study follows a non-experimental, cross-sectional, and descriptive methodology consisting of three stages: identification of variables, definition of variables, and construction of the tool. It finds that current smart city indicators focus primarily on technological aspects, efficiency, and management processes, overlooking important factors such as citizen engagement, their capacity to adopt technologies, and their research and knowledge-generation capabilities. This study makes a significant contribution to the field of smart city measurement and evaluation by using the triple-helix model as a conceptual framework. This approach strengthens the existing knowledge about this phenomenon and lays the foundation for future research in this area.
Three-Dimensional Urban Air Networks for Future Urban Air Transport Systems
Authors: Ditta Chiara Caterina , Postorino Maria Nadia
Published: September 2023

Advances in new electric aerial vehicles have encouraged research on pioneering Urban Air Mobility (UAM) solutions, which would provide fast service for passengers, goods, and emergencies. From this perspective, some air service scenarios have been identified, such as air taxis, airport shuttles, and intercity services. Such air services should be supported by a suitable urban air network, which should comply with several boundary conditions linked to the specific features of this new type of aerial mobility. This paper proposes an Urban Air Network (UAN) model that includes a third (vertical) dimension and whose aim is to satisfy the basic principle of linking origin/destination pairs, as in usual ground transportation networks, by guaranteeing at the same time safe aerial paths between origin/destination pairs with suitable vehicle separations. The proposed UAN consists of multiple 2D graphs on different layers, which allows for the transfer of aerial vehicles in lower airspace. A suitable cost function has been associated with each UAN link in order to compute the shortest paths connecting the origin/destination pairs. The links in a UAN have a dynamic nature and can be enabled or disabled in consideration of capacity issues. In addition, indirect CO2 emissions linked to aerial vehicles (such as operational and disposal phase charges) have been computed to foresee the potential environmental impacts based on the proposed UAN model. The preliminary results of a test case show encouraging results and provide interesting findings for further advancements.
Exploring the Potential of Biomass Pyrolysis for Renewable and Sustainable Energy Production: A Comparative Study of Corn Cob, Vine Rod, and Sunflower
Authors: Domazetovska Simona , Strezov Vladimir , Filkoski Risto V. , Kan Tao
Published: September 2023

The paper investigates the potential of biomass pyrolysis as a sustainable and renewable energy solution. The study focuses on three biomass types: corn cob, vine rod, and sunflower, which are abundant agricultural residues with potential for biofuel production. The pyrolytic gas, oil, and char produced during pyrolysis at a heating rate of 10 °C/min were analyzed. At the pyrolysis temperature of 500 °C, the corn cob showed the smallest final residual mass of 24%, while the vine rod exhibited the largest mass loss of 40%. Gas analysis revealed the concentrations of CO2, CO, H2, and CH4 in the pyrolytic gas, indicating its energy potential. Sunflower presented the largest calorific value of the produced biogas, while corn cob was the lowest. The chemical composition of the bio-oils was determined, with aliphatic acids identified as the dominant compounds, suggesting their potential for biodiesel production. Fourier Transform–Infrared Spectroscopy (FT-IR) analysis of raw biomass and char products demonstrated varying extents of decomposition among the biomass samples. A multicriteria assessment approach was employed to evaluate the differences between the selected three biomass feedstock and determined that sunflower biomass ranked the highest among the three, although the overall difference was small, confirming the suitability of all three biomass samples for pyrolysis conversion to higher-value-added fuels.
Advanced Biological Oxidation of Domestic Sewage with the Use of Compost Beds in a Natural Treatment System for Wastewater
Authors: Halicki Wojciech
Published: September 2023

Due to the progressing problems with ensuring sufficient quantity and quality of water for municipal, irrigation and economic purposes, the pressure to reuse treated wastewater is increasing. This fact forces the development of advanced systems enabling more effective wastewater treatment. This article presents the results of a 2.5-year study period in which compost beds, which are part of a natural treatment system for wastewater (NTSW), were used to treat domestic sewage by fully removing easily degradable organic matter and by fully nitrifying ammonium nitrogen. It was shown that the compost environment provides complete access to oxygen for the coexisting heterotrophic and autotrophic bacteria, covering 100% of their oxygen demand. Moreover, the outflow of treated wastewater shows an oxygen content of 4–7 g O2/m3. Advanced biological oxidation occurring in the compost beds with an area of 1 m2 per inhabitant and a daily hydraulic load of about 100 L/m2 can effectively and without additional energy expenditure provide a 98% reduction in biological oxygen demand and a 99.5% reduction in ammonium nitrogen. In addition, the effluent from the compost filters meets the most stringent quality criteria for (1) treated wastewater used for irrigation and (2) bathing water in terms of microbiological contamination.
A Review on Applications of Artificial Intelligence in Wastewater Treatment
Authors: Wang Yi , Cheng Yuhan , Liu He , Guo Qing , Dai Chuanjun , Zhao Min , Liu Dezhao
Published: September 2023

In recent years, artificial intelligence (AI), as a rapidly developing and powerful tool to solve practical problems, has attracted much attention and has been widely used in various areas. Owing to their strong learning and accurate prediction abilities, all sorts of AI models have also been applied in wastewater treatment (WWT) to optimize the process, predict the efficiency and evaluate the performance, so as to explore more cost-effective solutions to WWT. In this review, we summarize and analyze various AI models and their applications in WWT. Specifically, we briefly introduce the commonly used AI models and their purposes, advantages and disadvantages, and comprehensively review the inputs, outputs, objectives and major findings of particular AI applications in water quality monitoring, laboratory-scale research and process design. Although AI models have gained great success in WWT-related fields, there are some challenges and limitations that hinder the widespread applications of AI models in real WWT, such as low interpretability, poor model reproducibility and big data demand, as well as a lack of physical significance, mechanism explanation, academic transparency and fair comparison. To overcome these hurdles and successfully apply AI models in WWT, we make recommendations and discuss the future directions of AI applications.
Step by Step towards a Greener Future: The Role of Plogging in Educating Tomorrow’s Citizens
Authors: Martínez-Mirambell Carlos , Boned-Gómez Salvador , Urrea-Solano Mayra , Baena-Morales Salvador
Published: September 2023

The climate crisis remains a paramount challenge that contemporary society and forthcoming generations will grapple with. The significance of instilling sustainability awareness during formative years, particularly during adolescence, is underscored due to the potential for personality consolidation during this phase. In the educational context, physical education emerges as a valuable avenue to further the cause of a sustainable world by fostering student competencies across the three dimensions of sustainable development. Within this domain, activities such as plogging—an outdoor exercise that intertwines physical activity with litter collection—directly enhance environmental quality. However, a discernible gap exists in previous literature regarding high school students’ perspectives on this practice. Thus, this research aimed to integrate a plogging intervention within physical education lessons to assess student perceptions of this innovative activity. A cohort of 28 secondary school students (16 females and 12 males aged 15 ± 1.2 years) participated in this qualitative study. Semi-structured interviews consisting of nine questions were deployed to elicit narratives pertaining to their plogging experiences within an educational setting. Over four sessions, an active methodology rooted in plogging was employed, culminating in a hands-on excursion in a natural environment. The findings were bifurcated into two categories. The first pertained to reflections on the didactic experience, encapsulating its immediate impact and prospective implications. The second category offered a critical evaluation of plogging, underscoring predominantly affirmative views, especially those highlighting environmental benefits. Responses revealed high acceptance levels for plogging, a heightened awareness of littering, and a recognition of the tangible environmental benefits of such activities. For a sustainable future, it is imperative for adults to possess and impart profound environmental consciousness to younger generations. These insights can potentially catalyze further research on the integration of sustainability in physical education and the role of plogging as an instrumental classroom tool.
Optimizing Energy Consumption and QoS in WMSNs Using Queueing Theory
Authors: Abazeed Mohammed B. , Ali Mohammed , Alqahtani Ali
Published: September 2023

The limited resources and enormous amounts of data generated by multimedia sensors require efficient strategies to extend network lifetime while taking into account quality-of-service requirements such as reliability and delay. In contrast, limited battery resources require new techniques to balance energy consumption and multimedia application requirements in wireless multimedia sensor networks (WMSNs). These requirements are very critical, especially for network stability and performance. In this paper, an energy-efficient mechanism based on the M/D/1/B queueing model is proposed. According to the packets in the queue and the waiting time, the nodes decide their activation time, so the nodes wake up for a while to transmit the data in the queue and then go to sleep mode. The simulation results of the proposed algorithm show that the proposed mechanism achieves optimal values to reduce energy consumption while meeting the quality-of-service requirements under different conditions.
Efficient Removal of Cr(VI) by Protonated Amino-Bamboo Char Prepared via Radiation Grafting: Behavior and Mechanism
Authors: Zhao Yuan , Gao Jie , Liang Tian , Chen Tao , Han Xiaobing , Hu Guowen , Li Bing
Published: September 2023

Biochar is considered to be the most promising substrate for the preparation of environmentally functional materials. The modification of bamboo char can significantly improve the removal rate of toxic ions from wastewater; however, there are few reports that focus on the radiation grafting method. Here, glyceride methacrylate (GMA) is successfully grafted onto bamboo char through electron beam radiation, followed by amination using the existing epoxide group in diethyltriamine, and finally, treated with hydrochloric acid to obtain protonated diethyltriamine-functionalized bamboo char (CDGBC). The results of IR, TG, XRD, and SEM prove the successful fabrication of a CDGBC biosorbent. The results show that the solution pH has a great effect on the adsorption capacity, and a maximum adsorption capacity of 169.13 mg/g is obtained at pH = 2 for Cr(VI). In addition, the adsorption behavior of Cr(VI) onto CDGBC is demonstrated to obey the pseudo-second-order kinetic and Freundlich isotherm models, and thermodynamic analysis exhibits that Cr(VI) adsorption is an endothermic spontaneous process. A possible adsorption mechanism based on the electrostatic interaction, reduction, and surface complexation is proposed, according to the obtained results. This work confirms that radiation-induced grafting modification can effectively transform biochar into a high-performance adsorbent for Cr(VI) removal, offering a new approach to synthesizing an efficient biosorbent.
Mobile Learning in Higher Education: A Systematic Literature Review
Authors: Naveed Quadri Noorulhasan , Choudhary Heena , Ahmad Naim , Alqahtani Jarallah , Qahmash Adel Ibrahim
Published: September 2023

Mobile learning (M-Learning) has become a popular and effective method of education that leverages the ubiquity of mobile devices. M-Learning has digitally transformed the process of teaching and learning. It has tremendous potential to empower all sections of society through education and training. This study presents a systematic literature review of M-Learning. The articles were retrieved from Scopus and Web of Science databases. After applying inclusion and exclusion criteria, a final selection of 161 articles published between 2016 and 2022 was included in the review. To analyze the articles, the researchers employed the TCCM (Theory, Context, Characteristics, Methods) framework, which facilitated addressing the research questions. This review identified various theories, such as behaviorism, constructivism, cognitivism, situated learning, problem-based learning, context awareness learning, socio-cultural theory, collaborative learning, conversational learning, lifelong learning, informal learning, activity theory, connectivism, navigation, and location-based learning, that are used to support and guide the implementation of M-Learning. In terms of context, developing countries contributed to 70.8% of the studies, while developed countries contributed to 29.1%. Further, a majority of the studies, 93%, involved students followed by faculty members and only two studies involved staff from higher education management. A total of 19 unique characteristic factors have been identified, such as personal, intention, attitude, usage, utility, ease of use, learnability, social, technological, pedagogical, anxiety, enjoyment, accessibility, knowledge, experience, trust, price, and habit. A quantitative research design was used in 90% of the studies, followed by mixed methods research design in 7% of the studies, and qualitative research design in only 3% of the studies. Further, this article synthesizes previous research findings and highlights gaps for future research. Overall, this review contributes to the understanding and advancement of M-Learning as a valuable educational platform.
Fiscal Decentralization and County Natural Poverty: A Multidimensional Study Based on a BP Neural Network
Authors: Wang Bo , Deng Wanrong
Published: September 2023

To achieve the goal of long-term stable poverty reduction, it is necessary to implement not only economic poverty reduction but also natural poverty reduction and formulate a green and sustainable economic growth pattern, and finance is an effective means to affect economic poverty reduction and natural poverty reduction. This paper innovatively calculates the natural poverty index of 1712 county administrative units in China based on BP neural network and combines relevant county data to investigate the impact of county fiscal decentralization on natural poverty and its transmission mechanism from 2000 to 2020 using a two-way fixed-effect model, which provides a new interpretation perspective for green economy patterns and sustainable development. The main research results are as follows: First, the increase in county-level financial autonomy in China significantly increases the level of regional natural poverty, which is still valid after a series of robustness tests using the instrumental variable method, replacing the response variables and processing with a one-stage lag. Secondly, heterogeneity analysis shows that, on the one hand, the positive impact of county-level fiscal decentralization on the natural poverty index is different in regions with different natural poverty formation mechanisms. On the other hand, the reform of “provincial direct management of counties” has significantly improved the natural poverty situation in counties, indicating that an extensive fiscal and taxation system in the early stages of economic development aggravates regional natural poverty and that optimized fiscal decentralization is conducive to the alleviation of natural poverty. Finally, the mechanism analysis found that the local income impact and expenditure preference accompanied by the fiscal decentralization of counties strengthened the race to the bottom of taxation, guided industrialization, hindered technological progress and led to the deterioration of regional natural poverty. This research claims that encouraging local governments to deepen and improve the fiscal decentralization system, implement the concept of green finance, improve the ecological protection compensation mechanism and market incentive system and implement differentiated mitigation plans for different natural poverty counties are the crucial factors to achieving natural poverty alleviation at the county level and improving regional ecological sustainability in the future.
Effect of Crumb Rubber Modifier Particle Size on Storage Stability of Rubberized Binders
Authors: Vigneswaran Shyaamkrishnan , Yun Jihyeon , Jeong Kyu-Dong , Lee Moon-Sup , Lee Soon-Jae
Published: September 2023

This research study aimed to assess the influence of different particle sizes of crumb rubber modifier on phase separation when mixed with virgin asphalt binder (PG 64-22). Both Superpave and multiple stress creep recovery (MSCR) tests were conducted to determine the optimal particle size. Three sizes of crumb-rubber particles (≤0.5 mm, ≤1 mm, and 1–2 mm) were individually incorporated into the binder at a weight proportion of 10%. The findings revealed that an increase in particle size resulted in higher viscosity, which reduced workability. However, the use of particles with a size of ≤0.5 mm effectively decreased viscosity. Furthermore, larger particle sizes enhanced resistance to rutting and improved the lifespan of the pavement. Multiple shear creep recovery (MSCR) tests confirmed that larger crumb-rubber particles exhibited a higher load-bearing capacity. Additionally, phase separation studies demonstrated that larger particle sizes were associated with increased phase separation. Notably, particles with a size of ≤0.5 mm performed exceptionally well in reducing phase separation across all combinations. In conclusion, crumb-rubber particles with a size of ≤0.5 mm were identified as the most effective in minimizing phase separation when blended with virgin asphalt binder. These findings provide solid scientific evidence related to the effects of crumb-rubber particles on the storage stability of rubberized asphalt binder and have significant implications for future research in this field.
Quantitative Frequency Security Assessment of Modern Power System Considering All the Three Indicators in Primary Frequency Response
Authors: Tang Fei , Qi Junfeng , Liu Zhuo , Guo Yuhan , Deng Huipeng
Published: September 2023

The primary frequency response scale is deteriorating in the modern power system due to the high penetration of different power devices. Frequency security assessments are essential for the operation or stability-checking of the power system. Firstly, this paper establishes the Unified Transfer Function Structure (UTFS) of power systems with highly penetrated wind turbines. Based on the UTFS, this paper analyzes the three indicators of the primary frequency responses. Secondly, to better assess the security of the frequency, the secondary frequency drop (SFD) is avoided, with the frequency response parameters of the wind turbines calculated. Moreover, considering all three indicators of the primary frequency response, this paper proposes a frequency security margin index (FSMI). The FSMI divides the system stability margin into three levels, quantitively and linearly representing the frequency response capability of different power devices. Finally, to show the effectiveness and practicability of the FSMI, this paper establishes a simulation model with high wind energy penetration, including four machines and four zones in DigSILENT. Based on the FSMI, the frequency stability margins in different typical operating scenarios are divided into three zones: “Absolut secure”, “Secure” and “Relative secure”. The FSMI also shows the dominant frequency stability problem and the risk of system frequency instability for each zone. Considering the checking principles, the frequency stability margin is equivalently expanded by calculating the energy storage’s minimum frequency response capacity.
Constructing an Indicator System for Cultural Sustainability in Chinese Cities under the Objective of Urban Renewal and Capability Measurement
Authors: Ge Yunxiang , Lu Cheng , Gao Han
Published: September 2023

Urban renewal is a planning and renovation activity for cities, and pursuing cultural sustainability as a goal of urban renewal can expedite the achievement of high-quality and sustainable urban development. This paper uses the seven elements of cultural sustainability—Cultural Heritage (B1), Cultural Vitality (B2), Economic Vitality (B3), Cultural Diversity (B4), Place (B5), Eco-Cultural Resilience (B6), and Eco-Cultural Civilization (B7)—as the core indexes to develop a three-level indicator system applicable to cities with Chinese characteristics. The subjective–objective combination weighting method is then employed to assign weights to the indicators. Among them, Economic Vitality (B3) has the most significant weight, indicating that economic vitality significantly impacts the cultural sustainability of Chinese cities. In addition, the TOPSIS method was employed to assess typical Chinese cities. The assessment demonstrates that our cities can preserve cultural heritage, foster cultural vitality, attract a diverse population, and promote ecological civilization construction. The index system is exhaustive, the selection of indicators is appropriate, and the results of the practical application of the assessment are accurate and effective, allowing it to provide scientific planning guidance for urban renewal.
Illustration of Convective Boundary Conditions on the Darcy–Forchheimer Flow of Nanofluid with the Impact of Chemical Reaction
Authors: Pattanaik Priyashree Chandini , Jena Swarnalata , Mishra Satya Ranjan , Alshehri Mansoor , Shah Nehad Ali
Published: September 2023

The application of convective heat transport holds great significance in physiological studies, particularly in preventing the overheating of birds and mammals living in warm climates. This process involves the transfer of heated blood from the body’s core to the nearest blood vessels, effectively dissipating the excess heat into the environment. As a result, analyzing convective boundary conditions becomes crucial for understanding heat and solutal profiles in the flow of a two-phase nanofluid model (Darcy–Forchheimer), which also takes into account heat sources and chemical reactions. This model encompasses the combined effects of Brownian and thermophoresis phenomena on flow behavior. The development of a three-dimensional model leads to a set of nonlinear ODEs, which can be tackled using appropriate similarity variables and traditional numerical techniques, i.e., the Runge–Kutta fourth-order combined with shooting technique is adopted to obtain the solutions. To ensure the model’s accuracy, physical parameters are carefully chosen within their appropriate ranges to reflect real-world behavior. This approach helps to capture the physical essence of the system under study. It is observed that the streamlines for the proposed stream function shows the flow pattern of the fluid particles within the domain for the variation of the kinematic viscosity and stream values, and enhanced Brownian motion controls the fluid concentration.
Exact Solutions of the Oberbeck–Boussinesq Equations for the Description of Shear Thermal Diffusion of Newtonian Fluid Flows
Authors: Ershkov Sergey , Burmasheva Natalya , Leshchenko Dmytro D. , Prosviryakov Evgeniy Yu.
Published: September 2023

We present a new exact solution of the thermal diffusion equations for steady-state shear flows of a binary fluid. Shear fluid flows are used in modeling and simulating large-scale currents of the world ocean, motions in thin layers of fluid, fluid flows in processes, and apparatuses of chemical technology. To describe the steady shear flows of an incompressible fluid, the system of Navier–Stokes equations in the Boussinesq approximation is redefined, so the construction of exact and numerical solutions to the equations of hydrodynamics is a very difficult and urgent task. A non-trivial exact solution is constructed in the Lin-Sidorov-Aristov class. For this class of exact solutions, the hydrodynamic fields (velocity field, pressure field, temperature field, and solute concentration field) were considered as linear forms in the x and y coordinates. The coefficients of linear forms depend on the third coordinate z. Thus, when considering a shear flow, the two-dimensional velocity field depends on three coordinates. It is worth noting that the solvability condition given in the article imposes a condition (relation) only between the velocity gradients. A theorem on the uniqueness of the exact solution in the Lin–Sidorov–Aristov class is formulated. The remaining coefficients of linear forms for hydrodynamic fields have functional arbitrariness. To illustrate the exact solution of the overdetermined system of Oberbeck–Boussinesq equations, a boundary value problem was solved to describe the complex convection of a vertical swirling fluid without its preliminary rotation. It was shown that the velocity field is highly stratified. Complex countercurrents are recorded in the fluid.
On Laplacian Eigenvalues of Wheel Graphs
Authors: Alotaibi Manal , Alghamdi Ahmad , Alolaiyan Hanan
Published: September 2023

Consider G to be a simple graph with n vertices and m edges, and L(G) to be a Laplacian matrix with Laplacian eigenvalues of μ1,μ2,…,μn=zero. Write Sk(G)=∑i=1kμi as the sum of the k-largest Laplacian eigenvalues of G, where k∈{1,2,…,n}. The motivation of this study is to solve a conjecture in algebraic graph theory for a special type of graph called a wheel graph. Brouwer’s conjecture states that Sk(G)≤m+k+12, where k=1,2,…,n. This paper proves Brouwer’s conjecture for wheel graphs. It also provides an upper bound for the sum of the largest Laplacian eigenvalues for the wheel graph Wn+1, which provides a better approximation for this upper bound using Brouwer’s conjecture and the Grone–Merris–Bai inequality. We study the symmetry of wheel graphs and recall an example of the symmetry group of Wn+1, n≥3. We obtain our results using majorization methods and illustrate our findings in tables, diagrams, and curves.
Integrated Approach to Obtain Gas Flow Velocity in Convection Reflow Soldering Oven
Authors: Xie Bubu , Chen Cai , Lin Yihao , Chen Dong , Huang Wei , Pan Kailin , Gong Yubing
Published: September 2023

The nozzle-matrix gas flow velocity has a great influence on the accuracy of the temperature field of a printed circuit board assembly (PCBA) during the hot air convection reflow soldering process. This paper proposes a new approach that integrates the theoretical calculation, numerical simulation and an experimental test to accurately determine the nozzle-matrix gas flow velocity. First, the temperature profile of the aluminum alloy thin plate in convection reflow ovens is measured using a Wiken tester. Second, the nozzle-matrix gas flow velocity is theoretically calculated with the Martin formula. The computational fluid dynamic (CFD)simulation is performed according to the Icepak code, where a single oven chamber model is established to represent the 10 zones of soldering ovens to reduce computational resources considering the supry of the soldering ovens. The simulated temperature profile of the aluminum alloy thin plate is obtained and the specific response surface model (RSM) is established to represent the deviation between the simulated temperature and the measured temperature. Finally, based on reverse problem analysis, non-linear programming by quadratic Lagrangian (NLPQL) is used to solve the mathematical optimization model with the objective of minimizing the temperature deviation to obtain the corrected nozzle-matrix gas flow velocity. To validate the accuracy, the temperature test and the modeling using the corrected gas flow velocity for a new PCBA component for the soldering ovens is conducted separately. The temperature comparison between the simulation and the test shows that the maximum temperature deviation is within 10 °C. This provides evidence that the nozzle-matrix gas flow velocity obtained by the new approach is accurate and effective.