Understanding the Role of Teacher-Student Relationships in Students' Online Learning Engagement: Mediating Role of Academic Motivation.

Strengthening online learning outcomes requires the establishment of strong student-teacher relationships to engage students actively in learning activities. Teacher-student relationships are also pivotal factors for enhancing academic motivation for online learning engagement. Generally, however, research on online teaching remains underdeveloped. We aimed, in this study, to investigate the complex interplay in higher education in Pakistan between teacher-student relationships, academic motivation, and online learning engagement. We used Self-Determination Theory to frame an exploration of the impact of positive teacher-student relationships as mediated by intrinsic or extrinsic academic motivation on students' engagement in online learning activities. We administered a student self-report questionnaire to 437 participants from diverse universities in Sindh province. Using Structural Equation Modeling, we confirmed a model fit in which there were positive correlations between teacher-student relationships and students' online learning engagement; and between students' intrinsic and extrinsic academic motivations and their on line learning engagement. Our findings emphasized the need for communication, personalized support, and a sense of belonging in virtual education. Moreover, our findings revealed the mediating role of students' intrinsic and extrinsic academic motivation in teacher-student relationships, highlighting the nuanced dynamics of academic motivation in the virtual learning environment, with intrinsic motivation having the greatest mediating impact in the relationship between teacher-student relationships and on line learning engagement. Our study's practical implications include a need for professional educators to foster positive teacher-student relationships and integrate student motivational elements into online course design.

Secondary Atomization and Micro-Explosion Effect Induced by Surfactant and Nanoparticles on Enhancing the Combustion Performance of Al/JP-10/OA Nanofluid Fuel.

Aluminum/tetrahydrodicyclopentadiene/oleic acid (Al/JP-10/OA) nanofluid fuel is considered a potential fuel for aircraft powered by aviation turbine engines. However, an optimized formula for an Al/JP-10/OA system inducing a secondary atomization and micro-explosion effect and improving the burning performance needs to be developed. With this aim, in this work, the combustion characteristics of pure JP-10, JP-10/OA, JP-10/Al, and Al/JP-10/OA were experimentally tested, and a comparative analysis was conducted. Specifically, the influence of the surfactant and nanoparticle concentrations on the combustion characteristics of Al/JP-10/OA nanofluid fuel, including the flame structure, the flame temperature, the burning rate, the secondary atomization and micro-explosion effect, etc., were evaluated in detail. The results demonstrate that the addition of OA surfactant and Al nanoparticles had a significant effect on the burning rate of fuel droplets. The OA had an inhibition effect, while the Al nanoparticles had a promotion effect. As both OA and Al nanoparticles were added to the JP-10, the synergetic effect had to be considered. At the optimum ratio of OA to Al for the best suspension stability, there is a critical Al concentration of 1.0 wt.% from promotion to inhibition with increases in the Al concentration. The addition of OA and Al nanoparticles induced the secondary atomization and micro-explosion, resulting in an unsteady combustion and chaotic flame structure. The transient flame temperature of hundreds of Kelvins increased, the high-temperature flame zone widened, and thus, the energy release was elevated. Therefore, the combustion performance and energy release of Al/JP-10/OA nanofluid fuel can be improved through the secondary atomization and micro-explosion effect induced by the surfactant and nanoparticles.

Positive emotions, self-regulatory capacity, and EFL performance in the Chinese senior high school context.

Previous research on English as a foreign language (EFL) learning has predominantly focused on negative emotions such as anxiety and boredom, neglecting positive emotions. Self-regulation, a cognitive factor, has emerged as a key construct of positive psychology in recent years. However, few studies have examined the mechanisms by which positive emotions influence EFL performance, especially through cognitive factors. Given the high-stakes nature of Chinese college entrance examination and Chinese culture's value on effort, Chinese senior high school students may experience distinct EFL emotions. Therefore, this study, based on the control-value theory (CVT), explored the potential mediating role of self-regulatory capacity (boredom, awareness, goal, and emotion controls) in the relationship between the three focal positive emotions (enjoyment, hope, and pride) and EFL performance among Chinese senior high school students. A paper-and-pencil questionnaire survey was administered to 330 Chinese third-year senior high school students (male: n = 159; female: n = 171). The data were analyzed using descriptive statistics, correlation analysis, and mediation analysis with SPSS 26 and PROCESS V3.3. The results indicated that the students reported low levels of enjoyment and pride, moderate levels of hope, low levels of awareness, goal, and emotion controls, and moderate levels of boredom control. The results also revealed significant and large associations among the three positive emotions, the four components of self-regulatory capacity, and EFL performance. Furthermore, the results suggested that self-regulatory capacity partially mediated the effect of positive emotions on EFL performance, supporting the CVT framework. The study concluded with implications for educators and suggestions for future research.

Enhancing professional success: Chinese EFL teachers' workplace buoyancy and cognitive flexibility.

As integral to the EFL learners' achievement and intellectual development, good language teachers need to be familiar with the influential factors hindering or promoting their success. Positive psychology paying attention to positive traits highlights the factors that boost performance. In this line, by taking boosters of being a successful teacher, the aim of the current study is to consider the interplay between Chinese EFL instructors' professional success, workplace buoyancy, and cognitive flexibility. Then, it is considered whether EFL teachers' buoyancy and cognitive flexibility can predict success. Accordingly, 328 Chinese EFL teachers were conveniently selected to participate in this study. To analyze the collected data, multiple regression analysis and Spearman Rho correlation index as well as ANOVA were employed. The findings are an indication of a direct and significant correlation and coaction among EFL teachers' cognitive flexibility, workplace buoyancy, and professional success. Additionally, the results indicate that the cognitive flexibility of EFL teachers can be one of the significant predictors of success in their profession. Our findings imply that teachers need to enhance their positive personality traits such as cognitive flexibility and buoyancy to be successful in their profession.

Effect of Nanoparticle Addition on Evaporation of Jet Fuel Liquid Films and Nanoparticle Deposition Patterns during Evaporation.

Jet fuel-based nanofluid fuel has been proposed for improving the energy density and utilization efficiency of jet fuel that is widely applied in aircraft powered by aviation turbine engines. To recognize the evaporation behavior of the formed liquid film as a jet fuel-based nanofluid sprayed onto the engine wall or blades, this paper presents the evaporation and deposition characteristics of the jet fuel-based nanofluid liquid film adhering on the hydrophilic substrate. The changes in contact line, contact angle, volume, and deposition pattern during liquid film evaporation under different substrate temperatures, different nanoparticle concentrations, and different kinds of nanoparticle additions were investigated. The effect of nano-Al addition on the evaporation kinetics and deposition pattern of the nano-Al/jet fuel (nAl/JF) nanofluid fuel liquid film was explored. Repeated pinning and de-pinning of contact lines during evaporation occurred, resulting in the formation of concentric multi-ring deposition patterns. The addition of nano-Al increased the evaporation rate and shortened the evaporation lifetime, demonstrating a promotion effect on jet fuel liquid film evaporation. The existence of an energy barrier shows that the movement of three-phase contact lines on the hydrophilic solid surface presented not a continuous sliding behavior but a "stick-slip" behavior, and there were multiple jumps in contact lines and contact angles. Finally, a comparison was made with the deposition pattern of jet fuel liquid films with different graphite and Fe nanoparticle additions during evaporation. The mechanism of deposition phenomena was deeply revealed by the analysis of capillary flow and Marangoni recirculation.

Understanding of Contradiction on Concentration Effect on Stability, Physical Properties, Evaporation and Microexplosion Characteristics of Al/JP-10/Oleic Acid Nanofluid Fuel.

An Al/JP-10/oleic acid nanofluid fuel system has demonstrated potential in advanced combustion for aviation turbine engines. To improve the energy density of nanofluid fuel, a higher Al concentration requirement needs to be met. Correspondingly, a higher surfactant oleic acid concentration is required to maintain better dispersion stability. The increment of Al and oleic acid concentrations results in more frequent microexplosions, but a slower evaporation rate. Therefore, this paper proposes to deeply understand the contradiction of the concentration effect on the stability, physical properties, evaporation and microexplosion characteristics and obtain the best Al and oleic acid concentrations to maintain the most suitable comprehensive performance. Experiments on the stability, physical properties, evaporation and microexplosion characteristics were conducted, respectively. The analysis and discussion were then made to reveal the Al and oleic acid concentration effect on the stability, physical properties, evaporation and microexplosion characteristics. The results show that the optimum mass ratio of Al:oleic acid is 1:2 for the nanofluid fuels with Al concentrations of 2.5 wt.% or below, 1:2.5 for 5.0 wt.% or above to obtain the best stability. The physical properties of the nanofluid fuels such as density, surface tension and viscosity are linear, quartic and quadratic functions of Al concentration, respectively, relating to the internal flow and microexplosion of fuel droplets. With increasing oleic acid and Al concentration, the evaporation rates reduced, and the microexplosions became more frequent and intense. At a high ambient temperature of 600 °C, the evaporation rates were kept almost equivalent for JP-10, JP-10/oleic acid, and Al/JP-10/oleic acid fuels. It was found that the increment of ambient temperature can compensate for the reduction of the evaporation rate owing to the addition of oleic acid and Al nanoparticles, improving the evaporation and microexplosion performance.

Atomization Characteristics of Hydrogen Peroxide Solutions in Electrostatic Field.

Hydrogen peroxide (H2O2) can be considered as a sterilant or a green propellant. For a common use in industrial application, spray is an effective method to form fine H2O2 droplets. In this paper, electrostatic atomization based on the configuration of needle ring electrodes is proposed to produce H2O2 spray by minimizing its effective surface tension. The breakup performances of H2O2 ligaments can be improved by increasing the electric field intensity, reducing the nozzle size, and adjusting suitable volume flow rate. The smallest average diameter of breakup droplets for 35 wt. % concentration H2O2 solution reached 92.8 µm under optimum operation conditions. The H2O2 concentration significantly influenced the breakup performance owing to the concentration effect on comprehensive physical properties such as density, surface tension, viscosity, and permittivity. The average diameters of breakup droplets decreased with decreasing H2O2 concentration. At 8 wt. % concentration, the average breakup droplet diameter was reduced to 67.4 µm. Finally, electrostatic atomization mechanism of H2O2 solution was analyzed by calculating dimensionless parameters of Re, We, and Oh numbers with the combination of the operation conditions and physical properties for in-depth understanding the breakup behaviors. The calculation showed that the minimum average diameter of breakup droplets was obtained at 8 wt. % concentration at the investigated range of H2O2 concentration, which kept in agreement with the experimental results.

Chinese English as a Foreign Language Teachers' Immunity and Mindfulness as Predictors of Their Work Engagement.

Considering the significant contribution of teachers' professional triumph in the prosperity of students, the current study aims to investigate the existence of any relationship among three factors influencing teachers' success: immunity, mindfulness, and engagement. Furthermore, we attempt to investigate whether English as a foreign language (EFL) teachers' immunity and mindfulness can predict their work engagement. To this end, a Likert-scale questionnaire including items on teacher immunity, mindfulness, and work engagement was distributed to 582 EFL teachers in China through the WeChat application by employing a convenient sampling. To analyze the collected data, the Spearman Rho correlation index and linear multiple regression analysis are employed. The findings are that there does exist an indication of a direct relationship among EFL teachers' immunity, mindfulness, and work engagement. Also, it is found that immunity and mindfulness can predict EFL teachers' work engagement. The current study's findings support the necessity of training language teachers to cope with the EFL context adversities.

Effect of Nanoparticle Concentration on Physical and Heat-Transfer Properties and Evaporation Characteristics of Graphite/n-Decane Nanofluid Fuels.

n-Decane-based nanofluid fuels could be one of the most promising alternative fuels as aviation kerosene for aerospace application. However, the physical and heat-transfer properties of n-decane-based nanofuels have been rarely studied, and the influence of the concentration of nanoparticles on the evaporation characteristics of n-decane-based fuels has been sparsely investigated. This paper investigated physical and heat-transfer properties and evaporation characteristics of graphite/n-decane nanofluid fuels and emphasized the concentration effect of adding graphite nanoplatelets (GNPs) on these characteristics. It was found that there are a linear increase of density and thermal conductivity, a binomial increase of viscosity, and a binomial influence on surface tension as GNP concentration increases, while the boiling point almost remains constant, and the latent heat of vaporization largely decays. There exists a critical GNP concentration of 1.75 wt % for the evaporation performance. At 0∼1.75 wt %, the increase of GNP concentration benefits the evaporation. At 1.75∼4.0 wt %, the enhancement of GNP concentration deteriorates the evaporation performance. A detailed discussion of this evaporation behavior was made, which could be attributed to multiple factors, for example, the aggregation of nanoplatelets, the changes of physical and heat-transfer properties owing to the nanoparticle concentration effect, the surfactant concentration, and the ambient temperature. The concentration of surfactants has a binomial effect, and the ambient temperature has a linear effect on the evaporation rate. This study would promote in depth understanding of physical and heat-transfer properties and evaporation characteristics of nanofluid fuels and develop the application in turbine engines and ramjet engines.

Psychological Wellbeing, Mindfulness, and Immunity of Teachers in Second or Foreign Language Education: A Theoretical Review.

The emotions and affective factors of teachers play quintessential roles in academic contexts as they influence almost all aspects of their profession. T provide a theoretical review of some psychology constructs of teachers in this area, this study examines the psychological wellbeing, mindfulness, and immunity of teachers as three novel variables. More specifically, this study presents the definitions, dimensions, theories, and frameworks related to this domain drawing on positive psychology, complexity/dynamic systems theory, self-organization process, reflexive self-consciousness theory, integrative awareness theories, and mindfulness framework. These theoretical underpinnings explain the constructs and the way they function in second language education. Then, to provide evidence and justify the findings and propositions, empirical studies on each of the variables are reviewed. Finally, implications, research gaps, and suggestions for future inquiries are offered to interested researchers.

Formation and Elimination of Satellite Droplets during Monodisperse Droplet Generation by Using Piezoelectric Method.

One of the key questions in the generation of monodisperse droplets is how to eliminate satellite droplets. This paper investigates the formation and elimination of satellite droplets during the generation of monodisperse deionized water droplets based on a piezoelectric method. We estimated the effects of two crucial parameters-the pulse frequency for driving the piezoelectric transducer (PZT) tube and the volume flow rate of the pumping liquid-on the generation of monodisperse droplets of the expected size. It was found that by adjusting the pulse frequency to harmonize with the volume flow rate, the satellite droplets can be eliminated through their coalescence with the subsequent mother droplets. An increase in the tuning pulse frequency led to a decrease in the size of the monodisperse droplets generated. Among three optimum conditions (OCs) (OC1: 20 mL/h, 20 kHz; OC2: 30 mL/h, 30 kHz; and OC3: 40 mL/h, 40 kHz), the sizes of the generated monodisperse deionized water droplets followed a bimodal distribution in OC1 and OC2, whereas they followed a Gaussian distribution in OC3. The average diameters were 87.8 µm (OC1), 85.9 µm (OC2), and 84.8 µm (OC3), which were 8.46%, 6.14%, and 4.69% greater than the theoretical one (81.0 µm), respectively. This monodisperse droplet generation technology is a promising step in the production of monodisperse aerosols for engineering applications.