Search Results (2,628)

Drought, as a natural disaster with wide-ranging impacts and long duration, has an adverse effect on the global economy and ecosystems. In this paper, four remote sensing drought indices, namely the Crop Water Stress Index (CWSI), Vegetation Supply Water Index (VSWI), Temperature Vegetation Dryness Index (TVDI), and Normalized Difference Water Index (NDWI), are selected for drought analysis. The correlation analysis is carried out with the self-calibrated Palmer Drought Severity Index (sc-PDSI), and based on the optimal index (CWSI), the spatiotemporal characteristics of drought in Shaanxi Province from 2001 to 2021 were studied by SEN trend analysis, Mann–Kendall test, and a center of gravity migration model. The results show that (1) the CWSI performs best in drought monitoring in Shaanxi Province and is suitable for drought studies in this region. (2) Drought in Shaanxi Province shows a decreasing trend from 2001 to 2021; the main manifestation of this phenomenon is the decrease in the occurrence of severe drought, with severe drought covering less than 10% of the area in 2010 and subsequent years. The most severely affected regions in the province are the northern Loess Plateau region and Guanzhong Plain region. In terms of the overall trend, only 0.21% of the area shows an increase in drought, primarily concentrated in the Guanzhong Plain region and the outskirts of the Qinling–Bashan mountainous region. (3) Drought conditions are generally improving, with the droughts’ center of gravity moving northeastward at a rate of 3.31 km per year. The results of this paper can provide a theoretical basis and a practical reference for drought control and decision-making in Shaanxi Province. Full article

Understanding the factors that drive consumers to purchase electric vehicles (EVs) is critical to achieving decarbonization of China’s transportation sector, as well as mitigating global warming. This study aims to construct a research model based on altruistic and self-interested perspectives by integrating the Theory of Planned Behaviour (TPB) and Norm Activation Model (NAM) to predict the psychological factors that influence Chinese consumers’ intention to purchase EVs. Data were collected from 867 participants in China and empirically tested using Structural Equation Modeling (SEM). Self-interested factors, namely subjective norms, attitudes and perceived behavioural control, all had a significant positive effect on EV purchase intention. Additionally, the results showed that personal norms had the greatest effect on EV purchase intention. It was also found that awareness of consequence, ascription of responsibility and subjective norms were positive predictors of personal norms. Awareness of consequence had a positive effect on both the ascription of responsibility and attitudes. The findings contribute to understanding the psychological drivers of Chinese consumers’ intention to purchase EVs and can provide decision-making references for policy makers and manufacturers. Full article

The technological revolution has transformed the area of labor with reference to automation and robotization in various domains. The employment of robots automates these disciplines, rendering beneficial impacts as robots are cost-effective, reliable, accurate, productive, flexible, and safe. Usually, single robots are deployed to accomplish specific tasks. The purpose of this study is to focus on the next step in robot research, collaborative multi-robot systems, through flocking control in particular, improving their self-adaptive and self-learning abilities. This review is conducted to gain extensive knowledge related to swarming, or cluster flocking. The evolution of flocking laws from inception is delineated, swarming/cluster flocking is conceptualized, and the flocking phenomenon in multi-robots is evaluated. The taxonomy of flocking control based on different schemes, structures, and strategies is presented. Flocking control based on traditional and trending approaches, as well as hybrid control paradigms, is observed to elevate the robustness and performance of multi-robot systems for collective motion. Opportunities for deploying robots with flocking control in various domains are also discussed. Some challenges are also explored, requiring future considerations. Finally, the flocking problem is defined and an abstraction of flocking control-based multiple UAVs is presented by leveraging the potentials of various methods. The significance of this review is to inspire academics and practitioners to adopt multi-robot systems with flocking control for swiftly performing tasks and saving energy. Full article

This study investigates the long-term effects of demographic trends and admission rules on common properties in the Province of Trento, Italy, which we refer to as historical commons. Historical commons have evolved into socio-ecological systems over the centuries, meaning that communities governed collectively natural resources and lands essential for community survival. Communities and the admission rules that determine their composition are an important constituting element of historical commons because they have developed local ecological knowledge and practices of sustainable use of natural resources. Our study hypothesizes that commons continuity is endangered because of the declining trend of the size of communities being influenced by demographic trends coupled with admission rules. Grounding our research in systems dynamics, we use empirical data including demographic projections and existing admission rules to simulate their effect on the site of the community using the Province of Trento, Italy, as our study region. To achieve that, three types of historical commons are identified: open, semi-open, and closed, each with different admission criteria based on inheritance and/or residency. Results indicate that inheritance-based admission rules can significantly reduce the number of commoners over time, potentially endangering the continuity of these self-governance institutions. The study discusses the results in light of the literature on historical commons’ continuity to evaluate different policies affecting the size of the community grounding on different mental models. The study concludes that a simulation approach can promote an anticipatory approach to the co-design of policies to ensure inclusive continuity of historical commons. Full article

Introduction: Empirical evidence shows that many family carers, especially immigrants, experience considerable health disadvantages and poorer quality of life. Australia has a rapidly increasing multicultural population, officially referred to as Culturally and Linguistically Diverse (CALD) people. This paper explores similarities and differences in the carer profile and physical and mental health of CALD and non-CALD family carers. Methods: A cross-sectional anonymous survey was conducted of self-reported family carers aged 18 years and older. Identical paper and online survey modes were provided to enable choice. Key variables included demographic and carer profile, diagnosed chronic physical health conditions, and validated scales such as CESD-12 and MOS-SF12, including derivative composite Physical and Mental Component Summary (PCS and MCS, respectively) scores. The sample comprised 649 participants (CALD = 347, non-CALD = 302). The analyses included univariate, bivariate, and multivariable linear regression analyses for three outcome variables: PCS, MCS, and CESD-12. Results: CALD carers were comparatively younger and married, and 54% had university-level education (29% in the gfvnon-CALD group). Women were primary carers in both groups (67.4% versus 72.2%). The weekly care hours were higher for non-CALD carers. Both groups had below population-referenced scores for mean PCS and MCS values. For CESD-12, non-CALD respondents had higher scores (17.5 vs. 11.2, p < 0.022). Regression analyses showed significant differences for demographic, carer, and physical health variables across the three outcome variables. Discussion and Conclusion: Women have a higher domestic workload, which, when combined with high care hours, adversely impacts physical and mental health. The need for improved and culturally aligned care support systems is required. Full article

This paper describes the unique full-scale bollard pull and self-propulsion tests of a large amphibious tracked military vehicle with two waterjet propulsors. To provide a reference for the self-propulsion and cavitation performance, a series of sea trials and bollard pull tests were performed in a military sea bay and in a large test basin, respectively. Good overall agreement between the sea trial and the computation was observed in the speed–power relationship. The cavitation-induced breakdown phenomenon was further explored via numerical simulations. The results indicated that the uncertainties in the numerical results were dominated by the scales of vapor bubbles. The analysis showed that the selection of the vapor bubble scale factors of 1.0 for growth and 0.05 for collapse were in good agreement with the experimental results. Rapid performance breakdown occurred when sufficient suction side-attached cavities were extended into the blade mid-chord and tip-board regions. Full article

Globally, the construction industry is facing a severe labor shortage, and attracting and retaining workers has become a pressing challenge. This study examined the effect of rehabilitation exercise on construction workers’ willingness to sustain their careers through a questionnaire survey of 479 construction workers using a quantitative research methodology. It aims to reveal how the self-efficacy, perceived usefulness, and self-regulation of rehabilitation exercise affect construction workers’ occupational sustainability through physical and psychological recovery. The results of the study show that (1) the rehabilitation exercise self-efficacy and perceived usefulness of recovery exercise positively affect construction workers’ career sustainability intentions and (2) psychological recovery and physical recovery play parallel mediating roles in the effects of rehabilitation exercise self-efficacy, the perceived usefulness of recovery exercise, and self-regulation of recovery exercise on construction workers’ career sustainability intentions. The findings suggest that improving the physical and psychological capital of construction workers through recovery exercise can effectively enhance their career commitment and willingness to be sustainable. This study provides a reference for the design of more comprehensive and systematic rehabilitation and health management programs in the future and offers suggestions from the perspective of recovery exercise for the development of sustainable construction workers. Full article

With roots in the early 1960s, decoloniality as a sub-sect of postcolonial studies made successful attempts at redefining and unearthing essentially Western conceptualizations of knowledge and knowledge formation across different fields of endeavor. Many academic disciplines have benefited from decolonial studies’ self-reflective theories and deconstructive approaches, and religion and science should not be an exception. Within religion and science as an academic field, Western and European intellectual frames have been overwhelmingly presented as definitive of globalized perspectives and knowledge, especially the definition of “religion” and “science” within the academic field. The subtle but evident impact of adopting Western epistemology as ‘the’ definitive reference frame for all peoples and cultures is the transposition of colonial and overtly Eurocentric conceptualizations and definitions of what religion and science mean as perfunctory for what religion and science should mean within non-Western frames as well as a disregard for the latter. This has led to the presentation (or overrepresentation, according to Sylvia Wynter) of a single homogenized perspective for meaning-making and interpretation of topics and themes within the field, a decision which has not only significantly impacted the field, in terms of ongoing dialectics about the relationship between religion and science, but which has also seen the exclusion of other forms of beneficial epistemic reference frames, which have been viewed as subaltern. Drawing from Wynter’s epistemic disobedience, this paper highlights decolonial approaches for engaging in the academic study of science and religion, and which will advance the path towards delinking the field from Euro-Western conceptualizations. This will unravel the rich epistemic formation within non-Western knowledge frames and the inclusion of which will greatly enrich and redefine the academic study of religion and science in the days ahead. Full article

Background and Objectives: Statistics are of paramount significance to physicians as they allow them to critically interpret the medical literature and to contribute to it. However, teaching statistics to medical students and physicians, as well as learning statistics, is nothing short of difficult and anxiety-inducing to a great extent. Materials and Methods: In this study, an example of a novel approach to teaching statistics to medical students is introduced at a single college of medicine in Saudi Arabia. In this retrospective report, a new approach that has been developed and delivered to students is described. Results: The approach, referred to as the personal experience pathway, is part of a major curriculum change to the MBBS program. The track presents statistics to students as a tool, rather than a subject, that students will need to interpret results, either present in the literature or those of the research projects they are conducting. The outcome of this process has been assessed through measuring students’ scholarly output through student self-reporting and has been followed up over four student cohorts graduating between the years 2019 and 2022. The approach has successfully equipped students with a solid foundation of statistical understanding that has allowed them to publish in peer-reviewed journals. Such scholarly output has increased significantly over the last two years. Conclusions: The current study presents a framework through which the detailed curriculum plan could be applied to other medical schools, nationally and internationally, which will better prepare future statistically oriented physicians. Full article

It is well known that the flutter performance of a section is sensitive to the changing wind angles of attack. Exploring the thin plate’s flutter mechanism under different angles of attack is excellent, which helps understand inner flutter characteristics and ensures structural safety. This study investigated flutter derivatives of a thin plate with an aspect ratio of 40 under different wind angles of attack via the forced vibration technique. The otherness of aerodynamic damping and phase lag under different wind angles, which helps in understanding the flutter mechanism, are analyzed using the bimodal-coupled flutter method. It is shown that coupled vertical–torsional flutter dominated the flutter modality under 0° and 3° wind angles of attack. The critical flutter velocity dramatically decreased with increasing wind angles of attack which is attributed to the increasing negative aerodynamic damping induced by coupled self-excited forces and the decreasing positive aerodynamic damping induced by uncoupled self-excited forces. Moreover, the vertical motion lags behind the torsional motion under the 7° angle of attack, which was totally contrary to other angles of attack. Major works in this study reveal the aerodynamic mechanism of the weakened flutter performance of thin plates under large wind angles of attack and provide a reference for the flutter analysis of thin plates. Full article

Four-dimensional printing refers to a process through which a 3D printed object transforms from one structure into another through the influence of an external energy input. Self-folding structures have been extensively studied to advance 3D printing technology into 4D using stimuli-responsive polymers. Designing and applying self-folding structures requires an understanding of the material properties so that the structural designs can be tailored to the targeted applications. Poly(N-iso-propylacrylamide) (PNIPAM) was used as the thermo-responsive material in this study to 3D print hydrogel samples that can bend or fold with temperature changes. A double-layer printed structure, with PNIPAM as the self-folding layer and polyethylene glycol (PEG) as the supporting layer, provided the mechanical robustness and overall flexibility to accommodate geometric changes. The mechanical properties of the multi-material 3D printing were tested to confirm the contribution of the PEG support to the double-layer system. The desired folding of the structures, as a response to temperature changes, was obtained by adding kirigami-inspired cuts to the design. An excellent shape-shifting capability was obtained by tuning the design. The experimental observations were supported by COMSOL Multiphysics^® software simulations, predicting the control over the folding of the double-layer systems. Full article

To investigate the impact of different computational strategies on the self-propulsion hydrodynamic performance of a submarine model, a study was conducted using the RANS method, employing both the steady-state Moving Reference Frame (MRF) method and the unsteady Rigid Body Motion (RBM) method. Numerical simulations of the self-propulsion hydrodynamic performance of the submarine model were performed under different computational strategies, including submarine with propeller, submarine first and propeller second, and propeller rotational speed iteration. The differences between these strategies were analyzed from various perspectives, such as submarine resistance, propeller hydrodynamic performance, total solver actual runtime, propeller unsteady bearing forces, and induced fluctuating pressure. The results indicated that when conducting numerical simulations of the self-propulsion hydrodynamic performance of the submarine with a propeller, the fluctuation ranges of the submarine resistance, propeller thrust, and torque obtained by the steady MRF method were within 0.1% to 0.8%, compared with the three strategies in the unsteady state. In terms of computational efficiency, strategy 3 (RBM—submarine with a propeller) had the lowest computational efficiency, and the time to obtain a self-propulsion curve was 11.9 times, 4.4 times, and 3.1 times that of strategy 1 (MRF + RBM—submarine with a propeller), strategy 2 (RBM—submarine first, then propeller), and strategy 4 (RBM—propeller rotational speed iteration). When analyzing the propeller excitation forces under the submarine’s self-propulsion state using the steady-state MRF method combined with the unsteady RBM method, the frequency domain peak fluctuations were within 5% compared with the three strategies in the unsteady state, making this method suitable for numerical simulations of propeller excitation forces. These findings provide methodological support for evaluating the performance of the submarine’s hydrodynamic propulsion system. Full article

In order to realize effective laser communication on underwater mobile platforms, the active tracking and alignment technology of underwater laser communication (UWLC) is studied. Firstly, the servo control principle of the UWLC system is analyzed. Secondly, aiming at underwater disturbance, an adaptive fuzzy PID controller is designed to realize parameter self-tuning, thereby improving the system’s anti-disturbance ability. The designed algorithm was simulated, and the simulation results show that the adaptive fuzzy PID algorithm has better anti-disturbance ability and tracking performance than the traditional PID. Finally, an experimental platform was built for dynamic tracking experiments, and the results show that the dynamic tracking accuracy of the designed control algorithm was improved by 30.29% compared with the traditional control algorithm, which provides a certain reference for the development of laser communication on underwater moving platforms. Full article

Water quality assessment is an important method for understanding the spatial-temporal variation characteristics of water quality. Therefore, the present study has been performed to evaluate the water quality for a typical plain river network area in Changzhou City, Jiangsu, China, where the river system is characterized by reciprocal flow and diverse pollution sources. The water quality samples from 2017 to 2021 were comprehensively assessed using comprehensive methods that combine the single-factor pollution index (SFPI) method with multivariate statistical analysis. Initially, statistical analyses were conducted to evaluate water quality exceedances and correlations and the SFPI method was applied to classify water quality categories. Furthermore, principal component analysis (PCA) and cluster analysis (CA) were employed to reduce the dimensionality of water quality indicators and group monitoring sections with similar characteristics. The results indicate that the overall water quality in Changzhou City is lightly polluted with a trend of improvement. The primary pollutants identified are total phosphorus (TP) and ammonia nitrogen (NH₃-N). This study highlights that organic pollution, self-purification capacity, and eutrophication of river water bodies are the most significant factors affecting water quality. The sampling sites were classified into three groups (good, moderate, and poor). The water quality assessment results of this study provide a theoretical reference for water environment management and ecological protection in plain river network areas. Full article

In response to the problems of low control accuracy, single detection of operating parameters, and insufficient collaborative control of unmanned fertilization in field fertilization operations, this paper proposes an adaptive control strategy for fertilizer discharging shaft speed based on segmented linear interpolation method. By constructing a relationship model between fertilizer discharging shaft speed and motor control signals in different speed ranges, the on-site self-calibration of fertilizer discharging shaft speed and the precise control of the fertilization rate is achieved. At the same time, real-time detection and warning technology for multiple working condition parameters were integrated, and a bus communication protocol between unmanned tractors and variable-rate fertilizer applicators was developed. A variable-ratefertilization monitoring system based on unmanned tractors was developed, and actual experimental tests were conducted to test the system’s performance. Among them, the calibration test results of fertilization rate showed that the discharging rate of the fertilizer apparatuses (p) was negatively correlated with the rotation speed of the fertilizer discharging shaft, and that the installation position of the fertilizer apparatuses affected the uniformity of fertilization between the rows of the fertilizer applicator. The speed response test of the fertilizer discharging shaft showed that the average response time (T_s) of the fertilizer discharging shaft speed controlled by the self-calibration model was 0.40 s, the average steady-state error (e_ss) was 0.13 r/min, and the average overshoot (σ) was 7.33%. Compared with the original linear model, the e_ss was reduced by 0.23 r/min, and the σ was reduced by 1.54 percentage points. The results of the fertilization status detection tests showed that the system can achieve real-time detection of different operating parameters and states, as well as collaborative control of tractors and fertilizer applicators. The results of the fertilization rate control accuracy test showed that the average fertilization control error of the system was 1.91% under different target fertilization rate, which meets the requirements of variable-rate fertilization field operations. This study can serve as a technical reference for the design and development of fertilization robots in the context of unmanned farm development. Full article