Sustainability

Predictive control is an advanced control technique that performs well in various application domains. In this work, linearised control design models are first derived in state-space form from the full nonlinear model of the 5 MW Supergen (Sustainable Power Generation and Supply) exemplar wind turbine. Feedback model predictive controllers (FB-MPCs) and feedforward model predictive controllers (FF-MPCs) are subsequently designed based on these linearised models. A neural network (NN)-based wind speed estimation method is then employed to obtain the accurate wind estimation required for designing a FF-MPC. This method uses a LiDAR to be shared between multiple wind turbines in a cluster, i.e., one turbine is mounted with a LiDAR, and each of the remaining turbines from the cluster is provided with a NN-based estimator, which replaces the LiDAR, making the approach more economically viable. The resulting controllers are tested by application to the full nonlinear model (based on which the linearised models are derived). Moreover, the mismatch between the control design model and the simulation model (model–plant mismatch) allows the robustness of the controllers’ design to be tested. Simulations are carried out at varying wind speeds to evaluate the robustness of the controllers by applying them to a full nonlinear 5 MW Matlab/SIMULINK model of the same exemplar Supergen wind turbine. Improved torque/speed plane tracking is achieved with a FF-MPC compared to a FB-MPC. Simulation results further demonstrate that the control performance is enhanced in both the time and frequency domains without increasing the wind turbine’s control activity; that is, the controller’s gain crossover frequency (or bandwidth) remains within the acceptable range, which is about 1 rad/s. Full article

Using n-butanol as an alternative fuel can effectively alleviate the increasingly prominent problems of fossil resource depletion and environmental pollution. Combined injection technology can effectively improve engine combustion and emission characteristics while applying combined injection technology to n-butanol engines has not been studied yet. Therefore, this study adopted butanol port injection plus butanol direct injection mode. The engine test bench studied the combustion and emission performance under different direct injection ratios (NDIr) and excess air ratios (λ). Results show that with increasing NDIr, the engine torque (Ttq), peak in-cylinder pressure (Pmax), peak in-cylinder temperature (Tmax), and the maximum rate of heat release (dQmax), all rise first and then drop, reaching the maximum value at NDIr = 20%. The θ0-90 and COV_IMEP decrease first and then increase as NDIr increases. NDIr = 20% is considered the best injection ratio to obtain the optimal combustion performance. NDIr has little affected on CO emission, and the NDIr corresponding to the lowest HC emissions are concentrated at 40% to 60%, especially at lean burn conditions. NOx emissions increase with increasing NDIr, especially at N20DI, but not by much at NDIr of 40–80%. With the increase in NDIr, the number of nucleation mode particles, accumulation mode particles, and total particle decrease first and then increase. Therefore, the n-butanol combined injection mode with the appropriate NDIr can effectively optimize SI engines' combustion and emission performance. Full article

The clean utilization of traditional energy and renewable, clean energy utilization are the key points of the energy structure transition in the Yellow River Basin. This paper constructs an evolutionary game model, with the participation of local governments and energy companies, to analyze the dynamic evolution of each game subject. The results from the study highlight three important facts about the energy mix transformation in the Yellow River Basin: (1) the high ratio of traditional clean energy utilization and the low ratio of renewable, clean energy utilization align with the actual energy use in the Yellow River Basin, which can better promote the inclusive development of both types of energy; (2) increasing the capacity to utilize both energy sources can improve the energy system resilience gains of game players, for example, at the immature stage of renewable, clean energy utilization technologies, local government’s willingness to subsidize renewable clean energy utilization is positively related to their energy system resilience gains; and (3) under the premise of ensuring the energy supply, the introduction of penalty parameters can ensure a reasonable share of both types of energy utilization, and an increase in the penalty parameters makes the game participants increase their willingness to implement energy structure transformation policies. Full article

In Pakistan, wastewater such as industrial and urban wastewater is widely used for agricultural irrigation despite its chemical and pollutant content. In this respect, it is important to determine the risks of heavy metal accumulation in various agricultural products and the risks to human health. The aims of this study were to assess the heavy metal(loid)s contamination in soil and sugar beet samples and to assess the health risks of heavy metal(loid)s to the population via the consumption of sugar beet. The heavy metal(loid) values in the wastewater-irrigated soil samples ranged from 0.260 to 4.053 mg/kg, and wastewater-irrigated sugar beet samples ranged from 0.051 to 1.666 mg/kg. In contrast to Cd, Ni, Cu, Fe, Mn, Cr and Zn, which appeared to pose a health risk, Pb, Co, and Cr had Health Risk Index (HRI) values lower than 1.0 and did not appear to pose a threat to human health. Cd accumulation with HRI values over 1 (144.8) indicated that this metal is likely to have a major negative impact on local health. Full article

As tourism risk communication has transitioned from an emerging theme to a growing field of research, it is essential to review existing studies to identify developments in it. Nevertheless, there is a lack of extensive research employing both bibliometric and meta-analysis of tourism risk communication, specifically on communicating risk to tourists. To fill this gap, first, we applied bibliometric analysis techniques to identify emerging research clusters by collecting 236 articles from 1985.1.1 to 2023.6.1. Second, to implement the meta-analysis, we selected the empirical results from the collected articles. Then, five studies were used as a series of different structures required for implementing meta-analysis. Through our research, the main results show that (1) emerging research clusters mainly focus on: (i) “risk communication”, “crisis communication”, and “tourism crisis”, (ii) “risk perception”, (iii) “health service”, “health education”, “health behavior”, “environmental health”, and “public health”. (2) Papers aiming at data analysis or modeling are of great value to advance research in the field of tourism risk communication. (3) Tourism risk communication assessments reported by different public agencies are sensitive to factors such as gender, nationality, the experiences of tourists, local tourism boards, local governments, organizational resource allocation, and report evaluation. Based on this, we contribute to knowledge on tourism risk management by discussing the challenges of the present studies and, more significantly, by identifying seven antecedents and future research directions of risk communication strategy. Finally, this paper draws implications for theory development, acknowledges the limitations of this research, and indicates further research directions. Full article

Higher Education Institutions have adopted technology-based teaching methods to prevent the spreading of the contagious coronavirus (COVID-19). In the Fourth Industrial Revolution (4IR) era, technology-based teaching methods are indispensable for scaffolding teaching, learning and assessment. Mathematics is an important discipline in education, and provides a basis for problem solving, critical thinking and analytical skills, which is important to consider when focusing on sustainability. Thus, to add knowledge to the field about integrating technology-based teaching methods in mathematics, Higher Education environments during and post-COVID-19 need to be interrogated. This added knowledge is be valuable in the 4IR era post-COVID-19 for sustaining mathematics in Higher Education. This study explored participants’ experiences, views, implications and suggestions for technology-based teaching methods for mathematics. These participants (N = 45) were postgraduate students and mathematics school teachers at the research site in KwaZulu-Natal, South Africa. The research location for this qualitative study was a South African Higher Education Institution, and the study was conducted during the COVID-19 pandemic. The Community of Inquiry theoretical framework and the Substitution, Augmentation, Modification and Redefinition (SAMR) theoretical model guided this study. Participants were invited to two interactive online workshops. At these workshops, participants were introduced to different technology-based teaching methods. Then, they were invited to individual online interviews. The findings of this study suggest important experiences, views and suggestions for using technology-based teaching methods in Higher Education mathematics contexts in the 4IR era. These findings provide important implications and further research possibilities for embedding sustainable mathematics in Higher Education in the 4IR era, post-COVID-19. Full article

The Guangdong–Hong Kong–Macao Greater Bay Area (GBA) is rich in natural and marine resources, and it is scientifically valuable to study the evolution patterns and driving mechanisms of the ecosystem service values (ESVs) of the GBA for the governance and conservation of its ecosystems. Based on the land use changes in the GBA from 2000 to 2020, the ESVs in the GBA were measured at the grid scale, and the Markov model was used to predict the ESVs in 2030; the calculated results were used to analyze the spatial and temporal variation characteristics of the ESVs during the 30-year period, while the driving role of the topographic factors on the ESVs is revealed through the construction of the geographically weighted regression model (GWR). The results show the following: (1) During the 20-year period, the area of arable land and water in the GBA fluctuated greatly, with the area decreasing year by year and shifting mainly into construction land; in terms of shifting the center of gravity of the land, and the center of gravity of the grassland and unused land shifted the greatest distance due to the expansion of construction land, with the center of gravity shifting westward as a whole. (2) The ecosystem services (ESs) in the GBA show obvious aggregation in the spatial distribution, with the total ESVs decreasing year by year. Among them, the areas with an increasing total value are mainly located in the cities of Zhaoqing and Huizhou in the GBA, accounting for 27%, and the areas with a decreasing total value year by year are mainly located in the dense urban areas in the central part of the GBA, accounting for 35%, and the area is increasing, indicating that the habitat quality is deteriorating, and the model prediction shows that the value of ecosystem services in 2030 have a decreasing trend under the development of the natural state. (3) Topographic factors have a significant influence on the ESVs, and in terms of spatial distribution, the areas with the strongest effect are distributed in the northwestern and northeastern parts of the GBA, and the main uses for the land are wood land, arable land, water and the area of the water–land intersection near the sea. Full article

Forest recreation not only enables directly creates impacts on the entire tourism industry but also indirectly creates effects on other industries composed in an economic system via inter-industrial interdependence, such as backward and forward linkages or interactions. However, due to the lack of data available, few studies have been made exclusively for evaluating the impacts of forest recreation on the economy in a national dimension. Therefore, this paper attempts to analyze the economic impacts of the forest recreation industry. Using an input–output modeling approach, the industrial linkage and a cluster of economic multipliers are estimated based on new input–output tables for 2012, 2017, and 2018 that includes the forest recreation industry. The results indicate that, first, both the forward and backward linkages caused by forest recreation show rising trends over the analysis periods and the backward linkages are stronger than forward linkages. Second, the economic contribution of forest recreation has been strengthened, although the multipliers have shown a downward trend. The total output impact in 2018 is calculated to be $838.187 billion, with a total added impact of $352.713 billion. Furthermore, forest recreation could create over 18 million jobs with an average annual growth rate of 15.73%, which are mainly in the catering, accommodation, and retail industries with low skill requirements. Finally, policy applications are proposed to provide reliable and useful information for future planning and investment decision associated with the forestry and ecotourism industry. Full article

The Taohe River Basin is an essential ecological function area in the upper reaches of the Yellow River. Understanding the intricate trade-offs and synergies between ecosystem services (ESs) and exploring the impact of different factors are essential for achieving win–win outcomes in ecosystem management and socioeconomic development. The role of impact factors on the relationship between ESs, nevertheless, is more challenging to spatialize. This study used different models to estimate the net primary productivity (NPP), water yield (WY), and soil conservation (SC), and analyzed synergies and trade-offs between Ess. The spatial heterogeneity of the effects of natural and social factors on the relationships between Ess was explored using a geographic detector and a multi-scale geographically weighted regression (MGWR) model. The results show that: (1) NPP, WY, and SC all exhibit a rising trend, with multi-year averages of 488.99 gC/m², 157.29 mm, and 1441.51 t/hm², respectively; (2) NPP–WY and NPP–SC exhibit trade-offs in the majority of regions, while WY–SC are primarily synergistic in the upper and middle reaches, and they have the highest percentage of cropland, forest, and grassland; and (3) precipitation (PRE) has the greatest impact on the trade-off between NPP–WY and NPP–SC in the upper and middle reaches, and the gross domestic product (GDP), population density (POP), and distance from cropland (CROP) are the primary factors determining the synergy between NPP and WY in the lower reaches of the Loess Plateau cropping sector. PRE, digital elevation model (DEM), and CROP are the primary impact factors affecting the synergy of WY–SC. This study may serve as a reference for examining the evolutionary mechanism underlying the trade-offs and synergies between ESs and provide a scientific basis for future ecological environmental protection and regional land management in the Taohe River Basin. Full article

A shortage of skilled laborers has constrained the new development path called Construction 4.0, which is proposed to improve the construction industry with advanced technologies. It should be noted that the mismatch between labor skills and technological progress will harm the sustainable development of the construction sector. In China, a three-tier management structure consisting of contractors, labor subcontractors, and laborers is widespread in the labor market. Considering the relationship between laborers and construction firms, promoting construction labor professionalization depends on the cooperation of general contractors and labor subcontractors. Previous studies have focused on training techniques and methods, but have neglected to investigate whether stakeholders are willing to cooperate in training labor. Considering that the standard workforce is more likely to receive human resource investment, this paper aims to analyze the strategic choice of related stakeholders in cultivating the standard workforce. Since evolutionary game theory has proven to be an effective method to study the symbiotic evolution between stakeholders, this paper will apply it to develop an evolutionary game model and conduct analysis. Moreover, this research examines how government incentive policy affects the dynamic evolution process of cultivating a standard workforce. The results suggest that without government incentives, general contractors and labor subcontractors tend to choose a contingent workforce. When the government subsidy reaches a certain level, general contractors and labor subcontractors are willing to cooperate in cultivating a standard workforce. Additionally, it is worth noting that compensation for labor subcontractors is relatively more effective than that for general contractors in promoting construction labor professionalization. Furthermore, some suggestions and countermeasures are proposed to help to cultivate a standard workforce in China. Full article

Assessing water quality is crucial for improving global water resource management, particularly in arid regions. This study aims to assess and monitor the status of groundwater quality based on hydrochemical parameters and by using artificial intelligence (AI) approaches. The irrigation water quality index (IWQI) is predicted by using support vector machine (SVM) and k-nearest neighbors (KNN) classifiers in Matlab’s classification learner toolbox. The classifiers are fed with the following hydrochemical input parameters: sodium adsorption ratio (SAR), electrical conductivity (EC), bicarbonate level (HCO₃), chloride concentration (Cl), and sodium concentration (Na). The proposed methods were used to assess the quality of groundwater extracted from the desertic region of Adrar in Algeria. The collected groundwater samples showed that 9.64% of samples were of very good quality, 12.05% were of good quality, 21.08% were satisfactory, and 57.23% were considered unsuitable for irrigation. The IWQI prediction accuracies of the classifiers with the standardized, normalized, and raw data were 100%, 100%, and 90%, respectively. The cubic SVM with the normalized data develops the highest prediction accuracy for training and testing samples (94.2% and 100%, respectively). The findings of this work showed that the multiple regression model and machine learning could effectively assess water quality in desert zones for sustainable water management. Full article

The satisfaction of basic psychological needs leads students to engage in a sport modality on their own initiative. In the Spanish public educational system, mixed and heterogeneous, the gender and sport experience of students influence the teaching and motivation of invasion sports. This study investigated whether students’ gender and sport experience, and model influence the psychological variables (basic psychological needs and sport adherence) when teaching school soccer and basketball. Furthermore, correlations were calculated between these psychological variables. The study involved 165 fifth and sixth grade students (Mage, 11.27 ± 0.68 years old) from several Spanish state schools in the same autonomous community. A non-random convenience sample was used. The needs for autonomy, perceived competence and social relationships were measured using the Basic Psychological Needs in Physical Exercise Scale. Sport adherence was measured using the Measure of Intentionality to be Physically Active. A Confirmatory Factor Analysis, Cronbach’s Alpha, Average Variance Extracted and Composite Reliability were used to analyze the psychometric properties of the scales. Descriptive and inferential analyses were obtained after performing a Mixed Linear Model and a Bonferroni Post Hoc. There were significant differences in the autonomy need according to the students’ gender (boys > girls). In addition, boys who learned with the TGA model scored significantly higher than girls on this need. Attending to sport adherence, there were significant differences in favor of experienced students. Likewise, a regression analysis (structural equation model) revealed that the autonomy need showed low association with sport adherence. Higher perceived competence (β = 0.52) and social relationships (β = 0.36) were associated with greater adherence to sport (R² = 0.65). Teachers’ Knowledge and proper managing basic psychological needs will have educational, social and health benefits, as it will increase the likelihood of physical activity in and out of school. Full article

As the risks of climate change keep increasing, countries have emphasized the ecosystem adaptation policy, and the United Nation Environmental Program (UNEP) aids countries to adapt to a warming world with eco-based adaptation (EbA) measures for good ecosystem governance for boosting ecosystem adaptation services (EAS). With the purpose of helping to indicate the magnitude of the benefits of EAS from local EbA measures, this study assesses the economic value of the EAS of hillside forests regarding the residents in a climate vulnerable watershed, the Lanyang River watershed, by applying a single-bounded contingent evaluation method. The demographic variables and motivation variables indexed by perceived impacts are influencing factors in the residents’ willingness-to-pay. These variables are of significance in EbA policy application. The average economic value for each responding resident was estimated to be NT$ 793.65 on the basis of a survey of the residents’ willingness to pay for EAS and the single-boundary contingent valuation method. The results verified that the residents depend on the protection of natural hillside ecosystems. Considering the complex interactions between ecosystems and humans, the EbA is demonstrated to be a crucial method for mitigating the consequences of climate change. Protecting hillside ecosystems in the Lanyang River watershed through soil and water management presents critical policy implications. Now that climate change has become an emergency, this case study shows the success of Taiwan’s long manipulated EbA for EAS, with evidence of residents benefiting. This Taiwan case study has policy implications for the world and UNEP’s global EbA program to maintain EAS. Full article

The study of the time-dependent properties of engineering rock masses is a frontier topic in rock mechanics. In this study, creep tests and stress relaxation tests were conducted on mud-calcareous conglomerates from the Three Gorges Reservoir Area, and the long-term strength values of the conglomerate specimens were determined via different methods based on the test curves. By comparing these mainstream long-term strength determination methods, it was found that each of these methods have their own drawbacks. For example, the transition creep method requires a high accuracy of the test curve and only obtains an approximate strength interval rather than an accurate value. The long-term strength values determined by the isochronous stress–strain curve method are strongly influenced by subjective factors, among other things. Therefore, this paper proposes a new method for determining long-term strength, called the steady-state creep rate method, based on stress intervals. By comparison, the long-term strength values determined via this method are in good agreement with the transition creep method, the volume expansion method, and the stress relaxation method. Full article

While the concept of sustainable development has a history of more than 50 years now, with origins dating back to the 1972 United Nations Conference on the Human Environment, it would take the publication of the influential 1987 report of the World Commission on Environment and Development, Our Common Future, or the ‘Bruntland Report’ as it is commonly known (named after its chairperson, the then-prime minister of Norway) before the term’s use became more widespread [...] Full article

In recent years, the rise of the domestic industry has boosted the use and popularity of prefabricated buildings. Prefabricated buildings differ significantly from traditional design, construction, and production models. However, due to the short development period of prefabricated buildings in China, the quality management of these new structures is still not mature, resulting in frequent project delays and failure. To improve quality management, this paper aims to establish an evaluation model of factors affecting prefabricated building quality. The 4M1E framework was used to categorize and generalize related quality factors. Then, GeNIe software was used to establish a visual Bayesian network quality factor evaluation model. The factors that need to be managed and given attention to in the prefabricated construction project were discovered using reverse reasoning, sensitivity, and critical factor analysis. The results indicated that among the multiple stages of prefabricated buildings, the construction stage has the greatest impact on the quality of buildings. C2(Insufficient sense of responsibility of construction personnel) is the most significant factor that needs to be controlled. In addition, this paper combined the ISM-BN model with actual engineering projects to identify key factors affecting the project’s quality, demonstrating the model’s applicability. The evaluation model of quality factors in prefabricated buildings was established. It can identify the underlying causes of quality issues in prefabricated buildings and control engineering quality at the source, acting as an effective guide for practitioners and enterprises. Full article

To deal with global warming and fulfil China’s commitment to carbon neutrality by 2060, reducing carbon emissions has become a necessary requirement. As one of China’s three major economic circles, the Beijing–Tianjin–Hebei region (B–T–H) has a great responsibility. This paper measures energy-related carbon emissions of B–T–H from 2005 to 2019 and uses the extended Logarithmic Mean Division Index (LMDI) to decompose the carbon emission effect factors. Then, a Tapio index model was constructed to analyse the contribution of each effect factor. The results showed that: (1) the total carbon emissions of B–T–H increased by 1.5 times, with Hebei having the highest proportion, followed by Tianjin and Beijing. Coal was the biggest emitter in all three regions. Natural gas emissions in Tianjin and Beijing were growing rapidly. (2) Consistent with most studies, economic development promoted carbon emissions, while energy intensity and energy structure inhibited them. It was found that innovative factors also have significant impacts: research and development efficiency was the primary emission inhibition factor in Hebei and the secondary inhibition factor in Tianjin and Beijing. The effects of investment intensity and research and development intensity differed between regions. (3) Beijing took the lead in achieving strong decoupling, followed by Tianjin. Hebei maintained weak decoupling. Innovative factors also played an important role in decoupling, which cannot be ignored in achieving emission reduction targets. Full article

This article aims to systematically summarize the methods for intelligent operation of large public buildings, the integration and application of related technologies, as well as their development trends and challenges. (1) Background: In response to the rapid development and future needs of intelligent operation and maintenance, this study summarizes the development process of intelligent operation and maintenance in building operations, as well as relevant technical achievements and challenges; (2) Method: Quantitative and qualitative bibliometric statistical methods were used for overall analysis; (3) Result: Based on system theory, a B-IRO model was developed, and the current status of intelligent operation- and maintenance-related technologies and applications was sorted out. A framework for the entire industry was established, and future development trends were proposed as further research directions. Full article

This research entailed the production of composite materials through the combination of natural rubber and acrylonitrile butadiene rubber, along with nano-silica-loaded bismuth (III) oxide, in varying concentrations ranging from 0 to 45 parts per hundred parts of rubber (phr). The gamma attenuation properties of the composites at different concentrations of Bi₂O₃ were measured. Additionally, the mechanical properties of the resulting composites, including hardness, tensile strength, and elongation, were tested. The composites with a concentration of 20 phr exhibited the highest tensile strength and elongation at break, followed by a subsequent decrease as the concentration of Bi₂O₃ increased. The gamma mass-attenuation coefficient of the composites increased as the Bi₂O₃ concentration increased from 0 to 45 phr, with values ranging from 0.083 to 0.090 cm²/g at 0.662 MeV. Moreover, the fast neutron mass removal cross-sections ranged from 0.092 to 0.072 cm²/g, corresponding to the variation of Bi₂O₃ concentration from 0–45 phr are also determined. Various parameters related to gamma-ray shielding, including the half-value layer, exposure build-up factor (EBF) up to 40 mean free path (mfp) penetration depth, and effective atomic number (Z_eff) are also included. The radiation-induced aging of the prepared blend is tested by measuring the effect of radiation exposure on its shielding capability via its porosity change. The obtained results indicated that the prepared composites could be used for several radiation-protection applications. Full article