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Understanding the ontogeny of diving behaviour in marine megafauna is crucial owing to its influence on foraging success, energy budgets, and mortality. We compared the ontogeny of diving behaviour in two closely related species-northern elephant seals (Mirounga angustirostris, n = 4) and southern elephant seals (Mirounga leonina, n = 9)-to shed light on the ecological processes underlying migration. Although both species have similar sizes and behaviours as adults, we discovered that juvenile northern elephant seals have superior diving development, reaching 260 m diving depth in just 30 days, while southern elephant seals require 160 days. Similarly, northern elephant seals achieve dive durations of approximately 11 min on their first day of migration, while southern elephant seals take 125 days. The faster physiological maturation of northern elephant seals could be related to longer offspring dependency and post-weaning fast durations, allowing them to develop their endogenous oxygen stores. Comparison across both species suggests that weaned seal pups face a trade-off between leaving early with higher energy stores but poorer physiological abilities or leaving later with improved physiology but reduced fat stores. This trade-off might be influenced by their evolutionary history, which shapes their migration behaviours in changing environments over time.

School burnout, defined as prolonged feelings of exhaustion, cynical attitude and inadequacy feelings towards schoolwork, can lead to mental problems during adolescence. To find effective ways to prevent burnout, this study examined the synergistic role of two positive personal resources, a stress-is-enhancing mindset and academic buoyancy in relation to school burnout dimensions. The participants were 932 Finnish middle-school 9th-grade (age = 14–15) students. The results of SEM revealed that academic buoyancy and stress-is-enhancing mindset were jointly negatively related to one dimension of school burnout, cynicism. However, the stress-is-enhancing mindset had an indirect effect on all dimensions (exhaustion, inadequacy and cynicism) via academic buoyancy. The findings highlight their joint effect and especially the role of academic buoyancy in relation to school burnout. The implications of the results to burnout prevention and stress theories are discussed. [ABSTRACT FROM AUTHOR]

This study used a quasirandomized within-classroom design to investigate whether prior knowledge about physics gained in elementary school prepares students for future learning in related content areas in secondary school. A total of 433 children (intervention group) received four basic curriculum units on physics from their elementary school teachers. The units dealt with floating and sinking, air and atmospheric pressure, the stability of bridges, and sound and the spreading of sound. These children entered 60 newly composed classes in early secondary school that completed an advanced curriculum unit on hydrostatic pressure and buoyancy force with their secondary school teachers. A total of 942 students (control group) in these classes had not received the four basic physics curriculum units. On a conceptual knowledge test about hydrostatic pressure and buoyancy force, the intervention group outperformed the control group in the pretest (d = 0.28) and in the posttest (d = 0.25). Students in the intervention group showed similar learning gains as those in the control group, but when controlling for pretest performance, they achieved higher learning outcomes. Regression analyses within the intervention group revealed that this advantage resulted from the content-specific transfer of conceptual knowledge from topically related basic curriculum units. The basic physics instruction also prepared male and female students equally for future learning. Educational Impact and Implications Statement: Our study shows that students who have received early physics instruction in elementary school benefit slightly more from later, more advanced physics instruction in secondary school. This finding provides first evidence that the idea of a spiral curriculum, in which learners first build basic knowledge that is later on expanded in more demanding instruction, can work, although it is yet to be further examined how this process can be optimized in school instruction. [ABSTRACT FROM AUTHOR]

This paper investigates the effects of magnetohydrodynamics and heat transfer on the peristaltic transport of Prandtl fluid in a vertical endoscopic tube. The reduction of the complexity of the equations governing the flow of Prandtl fluid entails the use of long wavelength and low Reynolds number approximations. These complex equations for the pressure gradient and velocity profile are handled analytically using the perturbation technique with convective boundary conditions, and the temperature and concentration profiles are carefully solved for the exact solution. The frictional forces and pressure rise are also simulated with numerical integration. The resulting formulas for velocity, temperature, concentration, pressure rise, and pressure gradient are graphed using the MATLAB and MATHMATICA software, and the effects of all the different physical parameters are investigated and assessed. The streamlines with five distinct wave types are sketched at the conclusion to show the phenomenon of trapping. It is investigated that the velocity profile rises due to buoyancy forces and falls due to the influence of magnetic forces. [ABSTRACT FROM AUTHOR]

This paper explores the effects of egg orientation and yolk position during thermal processing using computational fluid dynamics simulation and experimentation. A carboxymethyl cellulose suspension was used to simulate the egg white, and a two‐dimensional model incorporated an air cell near the larger end. The simulation included four cases: two focused on vertical orientation with the yolk at the rear shell and the geometric center, and two on horizontal orientation with similar yolk positions. Repositioning the yolk in a horizontal orientation near the eggshell resulted in significant temperature variations. The findings show that a horizontal egg position, especially with the yolk near the eggshell, led to a significant 8%–16% reduction in heating times. This configuration also improved pasteurization efficiency, assessed by the F value, by about 13.8%. The study also revealed distinct flow patterns influenced by buoyancy forces, significantly related to temperature distribution inside the egg. [ABSTRACT FROM AUTHOR]

The impetus of this paper is to examine the natural convection of low-Prandtl-number fluid flow driven by buoyancy force in a differentially heated enclosure using the single-relaxation-time thermal lattice Boltzmann method owing to the broad range of applications of convective-based problems in industry, such as melting processes as well as energy storage systems. In this study, a proper force term incorporated in the collision operator has been utilized for computer code convergence (especially for Prandtl numbers less than 0.71). The side walls of the geometry are maintained by constant temperatures, Th and Tc, and the upper and lower walls are thermally insulated. The effects of Prandtl ( 0.05 ≤ Pr ≤ 0.71 ) and Rayleigh numbers ( 10 4 ≤ Ra ≤ 5 × 10 5 ) on the temperature fields, streamline functions, and average Nusselt number have been studied and found that at a given Prandtl number, the magnitude of vortices at the corner of the enclosure rises while those could disappear by Prandtl number increase. In addition, in the vicinity of hot and cold walls, the isotherms concentration increases due to rising temperature gradient and Prandtl number. The heat transfer coefficient grows with an increase in Ra and Pr numbers, experiencing a dramatic rise of 66.67% at the hot wall for Pr = 0.1. Similarly, the maximum velocity values near the cold wall rose by 185.71%. The suggested scheme has been validated by results shown in the literature, and excellent agreement has been found. [ABSTRACT FROM AUTHOR]

The current article investigates the effects of nonlinear mixed convection flow in an upright channel with asymmetric or symmetric heating and cooling conditions, considering the influence of temperature-dependent thermal conductivity. The momentum equation is approximated using the nonlinear Boussinesq approximation in the buoyancy force term. Computational solutions for the dimensionless partial differential equations are obtained through the use of an unconditionally stable and convergent implicit finite difference technique. A regular perturbation series approach is employed to ascertain steady-state solutions, facilitating the assessment of the correctness of the numerical approach. During the numerical computing process, it is observed that the nonlinearity in density variation with temperature, along with the mixed convection parameter and the symmetric or asymmetric heating and cooling of the plates, significantly influences flow generation. It is also noted that in the scenario of asymmetric heating, fluid motion is stronger at the bottom plate, whereas in the case of symmetric heating/cooling settings, the highest velocity is observed in the center of the channel. [ABSTRACT FROM AUTHOR]

Bristles in the first few rows float up from the rotor surface due to the radial airflow in the gap between the front plate and bristle pack, which directly affects seal performance and the service life of a brush seal. In this paper, firstly, two three-dimensional transient calculation models for a traditional brush seal (TBS) and a brush seal with disturbance-suppressing holes (DSBS) are established, respectively, based on the arbitrary Lagrange–Eulerian (ALE) method to study bristle deformation characteristics and leakage flow characteristics of the seals. Furthermore, effects of disturbance-suppressing (DS) hole structural parameters (i.e., height, diameter, and number of hole rows) were investigated to reveal the suppression mechanism of the DS holes on the buoyancy effect of bristles. The results showed that as soon as free ends of bristles at the first few rows moved along direction of the front plate in response to the radial airflow from the gap between front plate and bristle pack, a buoyancy effect of bristles occurred. The DSBS with DS holes set in the front plate of the TBS had a lower deformation of the bristles and a lower leakage amount of seal compared with that of TBS, indicating a good suppression to the buoyancy effect. With decreasing hole height and increasing hole diameter and number of hole rows, the suppression of bristle disturbance gradually increased due to decreases of the radial airflow and increases of torque acting on the bristles. [ABSTRACT FROM AUTHOR]

Entrainment rates at varying horizontal grid spacing were diagnosed and analyzed based on Large Eddy Model (LES) and Cloud Resolving Model (CRM) simulations of shallow and deep convection. Results show the estimated entrainment rates increase with increasing resolution, and the growth rate is roughly power‐law related to resolution. However, all commonly used parameterizations except for the buoyancy sorting scheme fail to reproduce the monotonic increase of entrainment with resolution, but rather a slight decrease instead. For these schemes, it is suggested the power‐law fitting formula derived from LES/CRM simulations can be used as a scaling function for high‐resolution entrainment correction. Preliminary tests show that the application of entrainment scaling largely reduces the parcel buoyancy and thus the convective available potential energy, favoring the reduction of parameterized convection at high resolution. Plain Language Summary: As model resolution continues to increase with increasing computational power, cumulus convection becomes partially resolved by the model grid, which requires parameterized convection to be reduced with increasing resolution. The purpose of this study is to investigate the scale dependence of entrainment rate, which is an important component in convection parameterization, by using multiple cloud resolving model simulations of shallow and deep convections. It was found that the estimated entrainment rates increase with increasing resolution, but most current entrainment schemes are unable to reproduce the monotonic increase in entrainment rate with increasing resolution. As a result, a scaling factor between entrainment and resolution was derived and suggested for use in correcting parameterized entrainment rates at high resolution. Key Points: The estimated LES/CRM entrainment rates increase with increasing resolution, and the growth rate is roughly power‐law related to resolutionThe majority of entrainment schemes fail to reproduce the monotonic increase in entrainment rate with increasing resolutionEntrainment scaling helps reduce the parcel buoyancy and thus the convective available potential energy toward higher resolutions [ABSTRACT FROM AUTHOR]

The formation of cold, dense waters south of the Antarctic Circumpolar Current (ACC) is one of the main drivers of the global overturning circulation, with major effects on the earth's climate. A key region where dense waters are formed is the Ross Sea, which is separated from the ACC by the Ross Gyre. The strength and variability of the Ross Gyre circulation impacts the formation and export of dense water, but observations of the Ross Gyre circulation are limited because of its remote location, severe weather conditions, and ice cover that has limited the application of remote sensing techniques. Quantitative estimates of the gyre's total strength are difficult to obtain from hydrographic observations alone due to the limited sampling and the relatively weak stratification. In this paper, we use a combination of observations and modeling studies to estimate the strength and variability of the Ross Gyre transport and investigate the relative contributions of the wind, buoyancy forcing, eddy fluxes, and the influence of ACC to the Ross Gyre circulation. We find that the mean transport of the Ross Gyre can be as high as about 45 Sv, more than twice the typical estimate of about 20 Sv. Sensitivity experiments to wind and buoyancy forcing, nonlinear terms, and the ACC were performed with a regional configuration of the Hybrid Coordinate Ocean Model (HYCOM). The numerical experiments show that the total Ross Gyre circulation, and its variability, are primarily wind-driven. The ACC is responsible for a small recirculation. Buoyancy and nonlinearity or eddy fluxes play a smaller role in the gyre dynamics, though they are regionally important. [ABSTRACT FROM AUTHOR]

In contrast to expectations, even buoyant microplastics like polyethylene and polypropylene are found at high concentrations in deep sediment traps and deep-sea sediments. To explain the presence of such buoyant microplastic particles at great ocean depths, several vertical transport mechanisms are under discussion with biofouling as one of the most referred. Biofouling is thought to increase the density of microplastic particles to the point that they sink to the deep sea, but this has mostly been shown on large microplastic particles ≥ 1 mm. However, although microplastics are defined as particles between 1 and 5000 μm, most microplastics are < 100 μm. In the ocean plastic particles continuously fragment, converting each "large" particle into several "small" particles, and particle abundance increases drastically with decreasing size. We argue that biofouling is not a reasonable transport mechanism for small microplastic particles ≤ 100 μm, which form the majority of microplastics. Biofilm density depends on its community and composition. A biofilm matrix of extracellular polymeric substances and bacteria has a lower density than seawater, in contrast to diatoms or large organisms like mussels or barnacles. We suggest that a small microplastic particle cannot host a biofilm community consisting of the heavy organisms required to induce sinking. Furthermore, to reach the deep sea within a reasonable timespan, a microplastic particle needs to sink several meters per day. Therefore, the excess density has to not only exceed that of seawater, but also be large enough to enable rapid sinking. We thus argue that biofouling cannot be an efficient vertical transport mechanism for small microplastic. However, biofouling of small microplastic may promote the likelihood of its incorporation into sinking marine snow and increase the probability of its ingestion, allowing its transport to depth. [ABSTRACT FROM AUTHOR]

Ensuring sustainability has increasingly become a significant concern not only in aquaculture but in the general agrifood sector. Therefore, it is imperative to investigate pathways to feed substitutes/best practices to enhance aquaculture sustainability. The application of fungi in aquaculture provides innovative methods to enhance the sustainability and productivity of aquaculture. Fungi play numerous roles in aquaculture, including growth, immunity enhancement and disease resistance. They also play a role in bioremediation of waste and bioflocculation. The application of fungi improves the suitability and utilization of terrestrial plant ingredients in aquaculture by reducing the fibre fractions and anti-nutritional factors and increasing the nutrients and mineral contents of plant ingredients. Fungi are good flotation agents and can enhance the buoyancy of aquafeed. Pigments from fungi enhance the colouration of fish fillets, making them more attractive to consumers. This paper, via the relevant literature, explores the multifaceted roles of fungi in aquaculture, emphasizing their potential to transform aquaculture through environmentally friendly and sustainable techniques. The effectiveness of fungi in reducing fibre fractions and enhancing nutrient availability is influenced by the duration of fermentation and the dosage administered, which may differ for various feed ingredients, making it difficult for most aquaculture farmers to apply fungi approximately. Therefore, the most effective dosage and fermentation duration for each feed ingredient should be investigated. [ABSTRACT FROM AUTHOR]

Migration pathways and distances of the oils in reservoir are thought to affect the distribution of pyrrolic compounds such as carbazole, its alkyl derivatives (alkylated carbazoles) and benzocarbazoles, although other factors, including maturity and depositional environments may also affect the distribution of these organic nitrogen compounds. In this study, 14 oil samples produced from conventional reservoirs in Pauls Valley, south Oklahoma were investigated using organic geochemical techniques. The sterane and hopane fingerprints suggest that most of the oils were sourced from the Devonian Woodford shale. Maturity parameters consistently indicate that the maturity level of the studied samples are all of similar maturity (Rc = ∼0.7%), suggesting the distribution of the organic nitrogen organic compounds is possibly reflecting variations in relative migration distances. The distribution of alkylcarbazoles revealed a preferential enrichment during migration, with the nitrogen-shielded alkylcarbazole tending to be enriched relative to the nitrogen-semi-shielded alkylcarbozoles particularly in oils produced close to the Arbuckle uplift to the east. Correspondingly, another family of pyrrolic compounds, benzocarbazoles, whose distributions also indicated that the Pauls Valley Woodford oils came from deeper part of the Anadarko Basin as the benzo-[a]/([a]+[c])-carbazole ratios decrease eastwards. In more specific migration systems, although the pyrrolic compound indicators are potentially disturbed by the structural complexes, the general migration directions suggest that the studied oils in Pauls Valley Hunton uplift were sourced from the deep basin area, and migrate upwards in porous sediments due to the buoyancy. This study investigates the feasibility of using pyrrolic compounds to estimate relative migration distances and will aid in the interpretation of migration history by using the distribution of carbazole, alkylated carbazoles, benzocarbazoles isomers in the Anadarko and Ardmore Basin petroleum systems. [ABSTRACT FROM AUTHOR]

This study investigated the rolling motion effect on the location of critical heat flux (CHF) for subcooled flow boiling within a mini-channel that is heated from one side. The study employed 15° and 25° as rolling amplitudes and 10 and 30 seconds as rolling periods across two different flow rate conditions. The CHF values observed under static conditions and those under rolling motion were subsequently compared. A key finding was that CHF consistently occurred near the highest positions of the rolling platform, where reduced buoyancy force, due to the absence of centrifugal acceleration, combined with only the radial buoyancy component acting in the flow direction, resulted in a slower bubble rise, facilitating easier coalescence of bubbles into a vapor film, leading to CHF. [ABSTRACT FROM AUTHOR]

Salt diapirs dominate the structure in many sedimentary basins and control the preservation and migration of hydrocarbon. The formation of salt diapirs generally falls into two endmember models: active (up-building) and passive (down-building) diapirism. In the active model, salt diapirs rise from salt buoyancy to pierce through the sedimentary overburden, whereas in the passive model, salt diapirs result from differential loading of sediments during deposition. These endmember models are mostly conceptual or kinematic, the mechanics of active and passive diapirism and their relative roles and interactions in the formation of salt diapirs remain uncertain. Here, we use two-dimensional high-resolution numerical models to investigate the primary factors and critical conditions for active and passive diapirism. Our results indicate that it is improper to use driving mechanisms to classify salt diapirs, because the buoyancy-driven active salt diapirism involves differential loading, while the passive diapirism requires salt buoyancy. The rise of salt diapirs is more sensitive to the effective viscosity of the overburden than to the salt viscosity. Stiff overburdens could prevent the rise of salt diapirs, but they could be pierced by salt diapirs if plastic yield of the overburden is allowed. During deposition, the coupled salt-sediment deformation, driven by both salt buoyancy and differential loading of sediments, can lead to various diapiric salt structures and minibasins. Regional tectonic stress generally promotes salt diapirism by enhancing strain weakening of salts and overburdens. We suggest that the classification of active and passive salt diapirism is an oversimplification in most cases. We propose a general model of the formation of salt diapirs that usually begins with dome initiation driven by salt buoyancy, followed by syndepositional down-building controlled by sedimentation and differential loading and ends with canopy formation when sedimentation stops. [ABSTRACT FROM AUTHOR]

Kelps are resilient organisms, capable of thriving in high-energy wave environments. However, when hydrodynamic drag forces exerted by the wave environment exceed the kelps' structural limits, individuals become dislodged. Floating kelps generally follow ocean currents, traveling long distances until air-filled structures fail or the epibiont load becomes too great, causing them to sink to the seafloor. The ability of kelp to disperse over vast offshore and nearshore systems makes them important for organic subsidy and as a dispersal vector for marine organisms. Previous research on dislodged macroalgae focused on context-specific rafts, limiting insights into the broader ecological role of floating kelp. This study employed a site-specific Lagrangian trajectory model to describe the spatial distribution of floating Ecklonia maxima along the South African coastline. The model incorporated buoyancy and sinking using site-specific morphological data. Findings revealed that the distribution of floating E. maxima is influenced by oceanographic conditions, and seasonal patterns were also evident. Mesoscale features played a vital role in kelp accumulation on the surface and seafloor and acted as barriers to dispersal. This study offers essential insights into kelp's role as an organic subsidy and provides numerical evidence for kelp's potential as a carbon sink, contributing to a better understanding of kelp ecosystems and their ecological functions. [ABSTRACT FROM AUTHOR]

The incompressible smoothed particle hydrodynamics is applied to simulate the suspension of the nano-encapsulated phase change materials (NEPCMs) within an astroid-shaped cavity. The astroid signifies a geophysical frontier of scientific significance in a mechanical profile of the solar system's origin. Hence, a novel geometry of an astroid shape is conducted in this work. An embedded baffle inside an astroid-shaped cavity is oscillating by an excitation motion $ x = a sin({\omega t}) $ x = asin (ωt). The oscillating motion of a baffle and double-diffusive convection inside an astroid-shaped cavity are handled by the ISPH method. The astroid-shaped cavity has low temperature and concentration in the bottom walls while the top walls are adiabatic. The numerical simulations clarified that an amplitude parameter of the oscillation motion varies the phase change zone and features of heat and mass transport inside an astroid-shaped cavity. The Stefan and fusion parameters are acting effectively in enhancing a phase change zone. The expanded baffle is utilizing to enhance the convective heat and mass transport and a phase change zone. The superior values of the average Nusselt and Sherwood numbers are obtained when the inner baffle is expanded due to higher buoyancy forces. [ABSTRACT FROM AUTHOR]

The impacts of hydrometeor-related processes on the development and evolution of the "21·7" extremely heavy rainfall in Zhengzhou were investigated using WRF simulations. Surface precipitation was determined by the hydrometeor microphysical processes (all microphysical source sink terms of hydrometeors) and macrophysical processes (local change and flux convergence of hydrometeors). The contribution of hydrometeor macrophysical processes was commonly less than 10%, but could reach 30%–50% in the early stage of precipitation, which was largely dependent on the size of the study area. The macrophysical processes of liquid-phase hydrometeors always presented a promotional effect on rainfall, while the ice-phase hydrometeors played a negative role in the middle and later stages of precipitation. The distributions of microphysical latent heat corresponded well with those of buoyancy and vertical velocity (tendency), indicating that the phase-change heating was the major driver for convective development. Reasonable diagnostic buoyancy was obtained by choosing an area close to the convective size for getting the reference state of air. In addition, a new dynamic equilibrium involving hydrometeors with a tilted airflow was formed during the heavy precipitation period (updraft was not the strongest). The heaviest instantaneous precipitation was mainly produced by the warm-rain processes. Sensitivity experiments further pointed out that the uncertainty of latent heat parameterization (±20%) did not significantly affect the convective rainfall. While when the phase-change heating only altered the temperature tendency, its impact on precipitation was remarkable. The results of this study help to deepen our understanding of heavy rainfall mechanisms from the perspective of hydrometeor processes. [ABSTRACT FROM AUTHOR]

Dynamic control of underwater vehicle manipulator systems (UVMSs) is the key part of underwater intervention tasks. In this paper, we propose an adaptive controller with a disturbance observer that mainly consists of two parts: the first part is the adaptive control law that estimates the changes in the center of mass (COM) and the center of buoyancy (COB) of the vehicle, and the second part is the nonlinear disturbance observer that estimates the external disturbance and model uncertainties. To attenuate the overestimation problem, a damping term is introduced to the adaptive law. The stability of the proposed method is proven on the basis of Lyapunov theory. We develop three scenarios on the Simurv platform and illustrate the effectiveness of the proposed method with a short response time and high tracking performance. [ABSTRACT FROM AUTHOR]

Changes in buoyancy of marine mammals can be used to infer environmental changes. In multiple seal species, how "fast" an animal sinks reveals body condition changes through shifts in buoyancy as the ratio between lean and lipid tissue changes. However, quantifying similar at‐sea changes in Weddell seals (Leptonychotes weddellii) has remained unexplored. Here, we present a method of inferring buoyancy of Weddell seals by monitoring descent rates from 4‐s time‐depth data, to reveal in situ insight of their life cycle. We defined a Buoyancy Indicator Segment (BIS) as the descent rate of a dive segment created with the broken‐stick method that was systematically filtered to only include characteristic nonstroking and directed travel segments while excluding lung buoyancy biases. We found that BISs predicted body condition changes in Weddell seals, being a function of dive duration, mean depth, and time‐of‐year. Descent rates quickened with troughs in early April due to postmolt muscle recovery, early July due to winter conditions, and early September possibly due to pregnancy. Each trough was followed by weight gain, with slowing descent rates reaching peaks in late May, early August, and late October. This new approach showed that determining at‐sea condition is possible for Weddell seals, deriving a powerful species and environmental monitoring tool. [ABSTRACT FROM AUTHOR]

Feeding strip significantly enhances continuous cast slab quality. To clarify its impact on inclusion distribution, a mathematical model coupling flow, solidification and inclusion motion have been developed. The upper recirculation, lower recirculation, and unformed recirculation flow occur during continuous casting. Under the resultant forces of drag, virtual mass, pressure gradient, Saffman, gravity, buoyancy, etc., the inclusion motion can be divided into two stages: Injection and Split flow. Feeding strip mainly affects inclusion motion by altering the drag, virtual mass, pressure gradient, and Saffman forces, which are closely related to the molten steel flow. After feeding strip, the lower recirculation on the strip feeding side is compressed, while it on the no-feeding side is expanded. The unformed recirculation flow on strip feeding side squeezes the flow below lower recirculation on no-feeding side. A higher strip feeding speed promotes downward inclusion motion, increasing the chance of being captured between the slab edge and strip. Unformed recirculation flow guides inclusions on the no-feeding side toward the slab edge, while expanded flow directs them toward the center. Consequently, inclusions on strip feeding side gradually gather between slab edge and quarter, while inclusions on no-feeding side first gather toward center and then toward edge of slab with increased strip feeding speed. [ABSTRACT FROM AUTHOR]

This paper investigates the Magnetohydrodynamics (MHD) convective flow over a cone with the influence of viscous dissipation, variable viscosity, chemical reaction and variable thermal conductivity effects. Related equations are tackled by the Homotopy analysis method (HAM). The impacts of physical variables on concentration, velocity and temperature are presented through numerical tables and graphs. It is noticed that the heat transfer rate (Nusselt number) increases against Prandtl number. Similarly, the mass transfer rate (Sherwood number) increases against Schmidt number. Also, it is seen that skin friction in tangential and azimuthal direction increases against the buoyancy forces ratio parameter. Current results are validated with previous literature work. [ABSTRACT FROM AUTHOR]

The investigation of the mixed convective magnetohydrodynamic (MHD) flow of a couple stress hybrid nanofluid having temperature‐dependent viscosity and thermal conductivity in a vertical channel is dealt with within this paper. The considered hybrid nanofluid is processed by mixing multiwalled carbon nanotubes (MWCNT$MWCNT$) and silver (Ag) nanoparticles in a base fluid of ethylene glycol (C2H6O2$\text{C}_{2}\text{H}_{6}\text{O}_{2}$) assuming the base fluid and the nanoparticles to be in a thermal equilibrium state following the Tiwari–Das nanofluid model. The flow is generated by the buoyancy force under the standard Boussinesq approximation and the pressure gradient force. The effect of a uniform transverse magnetic field is considered, and a constant temperature is maintained at the channel walls. The governing momentum and energy equations are nondimensionalized with relevant dimensionless parameters and solved using the homotopy analysis method (HAM) to obtain semi‐analytical solutions. The skin friction coefficient and Nusselt number on the channel walls are derived to analyze the shear stress and heat transfer rate, and to scrutinize the irreversibilities in the system, the entropy generation number and the Bejan number are defined. The emphasis is given to the analysis of velocity and temperature profiles, irreversibilities in the system, shear stresses, and heat transfer rate on the channel walls concerning the volumetric concentration of the nanoparticles, shape factor effect for various nanoparticle shapes, and temperature‐dependent viscosity and thermal conductivity. The analysis reveals that with higher shape factors and enhancement of nanoparticle concentration, both velocity and temperature degrade, and the entropy generation rate escalates with growing heat transfer irreversibility. Moreover, a lower and higher shear stress and heat transfer rate are achieved, respectively. The variable viscosity and thermal conductivity parameters effectively alter the velocity and temperature profiles, irreversibilities, shear stress, and heat transfer rate. [ABSTRACT FROM AUTHOR]

It is of great significance to sort specific types of cells through a fast and efficient technology in biomedical research and clinical applications. In this study, commercial hollow glass beads were modified with 3-aminopropyltriethoxysilane (ATPES) and hyaluronic acid (HA) sequentially, which can capture HeLa cells with nearly 100% efficiency within 10min. The beads can specifically recognize and sort HeLa cells from a cell coculture of HeLa and L-929 depending on their strong buoyancy and good affinity with cancer cells. The job provides a facile, quick and low-cost cell sorting method, which has potential application in the fields of specific and efficient cell isolation. [ABSTRACT FROM AUTHOR]

In the context of examination‐oriented education and the pressure of college entrance examinations (known as the “Gaokao”), Chinese high school students often experience academic burnout. Previous research has shown that effort–reward imbalance (ERI) is an important predictor of academic burnout among high school students, but the underlying psychological mechanisms are not yet clear. To address this research gap, we surveyed 415 Chinese high school students (226 males and 189 females, mean age = 15.82 years, SD = 0.87), and a self‐report questionnaire including the ERI scale, school connectedness scale, academic buoyancy scale, and academic burnout scale was completed by all participants. The data were analyzed by SPSS 24.0 and the PROCESS macro and developed a moderated mediation model incorporating school connectedness and academic buoyancy. The results showed that (1) ERI was significantly and positively associated with academic burnout among high school students; (2) school connectedness partially mediated the relationship between ERI and academic burnout; (3) academic buoyancy moderated the link between ERI and school connectedness, as well as between ERI and academic burnout. These findings are not only valuable for understanding the underlying mechanisms linking ERI and academic burnout but also contribute to the development of intervention programs (e.g., interventions based on academic buoyancy) aiming at reducing high school students' academic burnout. [ABSTRACT FROM AUTHOR]

Hybrid nanofluids provide several advantages over conventional fluids, including improved thermal characteristics, increased stability, customizable features, multifunctionality, and environmental advantages. Hybrid nanofluids are an appealing alternative for a variety of applications due to these benefits. This study aims to compute the non-similar solution of single-multi wall carbon nanotubes (SWCNTs-MWCNTs)-based hybrid nanofluid flow over an inclined extending surface. Heat transmission and flow are observed under the effects of quadratic convection, Darcy-Forchheimer quadratic drag forces, viscous dissipation, and non-linear thermal radiative heat flux. The velocity and thermal slip constraints are imposed at the inclined surface. For the model-based comparison, Xue, and Modified Hamilton Crosser thermal conductivity models for carbon nanotubes (CNTs) are adopted. The irreversibility of the system is also investigated using the second law of thermodynamics for the distinct CNTs-based thermal conductivity models. Non-similarity variables are adopted to convert nonlinear partial differential equations into dimensionless PDEs. Analytical modeling of non-similar systems is done by adopting non-similarity transformations up to second-level truncation, and the bvp4c technique is then used to compute the results numerically. The research found that at 75° of plate inclination, the Modified Hamilton Crosser model for CNTs outperforms the Xue model in terms of heat transfer rate. Further, entropy generation is significantly larger for the Xue model than for the Modified Hamilton Crosser model for CNTs against higher values of viscous dissipation and porosity parameters. It is also revealed that for opposing buoyancy force GR < 0, the temperature of the fluid escalates. This study possesses multiple applications including petroleum engineering, heat exchangers, environmental remediation, and biomedical applications. [ABSTRACT FROM AUTHOR]

Seed dispersal distance is an important indicator of how well a plant species can cope with environmental changes. Seeds of wetland plants are primarily dispersed by hydrochory (floating on the water surface) or endozoochory (ingestion and egestion by animals). However, both mechanisms can also be combined (diplochory), which increases dispersal distances. In wetlands, seeds often float on the water surface before ingestion and transport by animals, such as waterbirds. Here, we consider what happens next after endozoochory and test whether seeds dispersed inside waterbirds can then continue to disperse by hydrochory. We experimentally assessed the buoyancy capacity of 41 wetland plant species for 14 weeks before and after simulated passage through avian digestive systems. This revealed that (1) seeds of plants previously assigned a hydrochory dispersal syndrome floated longer than those from other syndromes, but with considerable overlap; (2) fully aquatic and shoreline plant species had seeds with stronger buoyancy than terrestrial plants; and (3) digestive processes negatively affected seed buoyancy capacity for all plant species, which included wetland species with a typical hydrochory syndrome. The capacity for hydrochory is more limited after endozoochory than beforehand, with strong implications for the effectiveness of seed dispersal. [ABSTRACT FROM AUTHOR]

A global inventory of extractive species mariculture in wave-exposed temperate waters shows that the longline is the technology used in more than 99% of the sites (Part 1 of this review). In this second part, I compare the static (longline at rest), quasi-static (tidal sea surface elevation, steady currents and mainline lifting operation) and dynamic (wind seas and swells) loading and motion of surface, semi-submerged and fully submerged longlines used to grow bivalves and kelp. This review is based on a hundred papers published on the subject mostly after 2010 and on simple analytical models used to illustrate the many compromises that must be made to ensure the survivability of the structure and the survival (retention), growth and quality of the cultured biomass. Surface longlines are unsuitable for fully exposed environments. To mitigate storm energy it is necessary to minimize the volume of surface buoys and submerge the mainline to the maximum depth possible. There is however a limit to minimizing the volume of surface buoys due to the uplifting of the mainline by currents. In the case of kelp, its optimal growing depth is within a few meters from the sea surface. This limitation can be partly circumvented by having the kelp float above the mainline. In the case of bivalves, mainline depth can be tens of meters below the sea surface. This comes with some disadvantages including difficulties in maintaining the delicate buoyancy balance, particularly for fully submerged longlines without legs, and reduced access to the mainline, particularly for fully submerged longlines with legs. Devices that allow autonomous or remote-controlled changes of mainline depth on a daily, occasional (husbandry and harvest operations) or seasonal basis have been tested but are not yet used commercially on longlines. [ABSTRACT FROM AUTHOR]

Educational activities are significant in that they have an important place in the life of the individual and support mental health. In this study, the relationship between mindfulness and academic buoyancy and the mediating role of academic hope were examined in a longitudinal research study. Data were collected from 287 Turkish university students who participated in the study at 4‐month intervals. An autoregressive analysis of the cross‐lagged panel model for a half‐longitudinal design was used to test the role of academic hope as a mediator in the relationship between mindfulness and academic buoyancy. The results revealed the direct effect of mindfulness on academic hope and academic buoyancy. In addition, academic hope was found to have a mediating effect on the relationship between mindfulness and academic buoyancy. It was, therefore, concluded that improving mindfulness practices may benefit people from both an academic and spiritual perspective. [ABSTRACT FROM AUTHOR]

This study addresses the applications of non-uniform heat source/sink and viscous dissipation in the magnetohydrodynamic (MHD) flow of Casson nanoparticles toward a porous stretchable sheet. The free convective flow for the inclusion of thermal buoyancy along with dissipative heat encourages the flow phenomena. The governing equations of the flow model are presented in terms of partial differential equations and then transformed into a system of ordinary differential equations using similarity transformations. These systems of equations are solved numerically by using the Runge–Kutta fourth-order method with a very efficient shooting technique. The effects of various parameters such as the Casson parameter, elastic parameter, porosity parameter, Prandtl number, non-uniform heat source/sink constant, Eckert number, skin fraction and Nusselt number on the flow area are computed and represented graphically. The present results reflect that the velocity of nanoparticles declined effectively with the porosity parameter and nanoparticle volume fraction. The temperature profile is increased with the elastic parameter and heat source parameter while decreasing with the Eckert number and Casson fluid parameter. Moreover, it is observed that when the Hartmann number is maximum, a retardation in wall shear force against nanoparticles volume fraction is marked. [ABSTRACT FROM AUTHOR]

The designation of this research is to scrutinize the influence of convective nanofluids over a three-dimensional exponential surface with chemical reactive species in a free stream fluid flow by following Buongiorno's model. The continuity, momentum, energy, concentration and motile microorganism density partial differential equations that make up the physical governing equation problems are simultaneously transformed into ordinary differential equations system. By using MATLAB programming, the RKF approach has been followed in order to implement the shooting technique to solve this system that explores how changing fluid parameters affect the profile of physical quantities of interest. A parametric analysis has been done in the current study. The effects of fluid parameters such as chemical reaction, Brownian motion, free stream velocity, Lewis number, thermophoresis, and Prandtl number on concentration, temperature, and velocity profiles are graphically represented. Moreover, Contour plots are also drawn against computational fluid parameters to get desired results. Furthermore, calculated results are correlated with already existing outcomes along with residual error. It is inferred that; thermal and concentration fields increase for higher thermal and concentration Biot numbers serially. Additionally, it is found that skin friction coefficient declines with inclination in thermophoresis Nt (1.0 ≤ Nt ≤ 3.0) and Prandtl number Pr (1.0 ≤ Pr ≤ 4.0). The present investigation aims to support production businesses in achieving the desired level of quality of their products by effectively managing the transport phenomena. [ABSTRACT FROM AUTHOR]

Turbulent plumes are fascinating to study in large part due to the ability to see the eddies and structures that comprise the exterior structure as they develop in space and time. We perform a laboratory study in which positively buoyant turbulent plumes are generated in a quiescent water tank. Buoyancy is varied by modifying the relative percentages of isopropyl alcohol to water in a mixture placed in a head tank. Photographs captured at steady frame rates record the evolution of the plume as it develops in time and space. A custom algorithm tracks the visible exterior outline of the plume, from which eddies and structures can be identified along the interface between the plume fluid and ambient fluid. Statistical analyses are performed to characterize differences in the distributions of external structures to study their dependence on relative buoyancy between the fluids. Spectral analysis of the edge signal of the plume reveals a - 2.2 slope, indicative of the range of eddy lengths that comprise turbulent plumes. We explore the relationship between buoyancy with both the plume front velocity and plume spread angle. We find the front velocities to be functions of both the buoyancy and source Reynolds number. However, the spread angles were found to vary only with buoyancy of the plumes, thus proportional to their Richardson numbers. [ABSTRACT FROM AUTHOR]

This paper reports the experimental results of the vortex-induced vibration (VIV) of an S-shaped flexible riser hanged underneath a two-degree-of-freedom (2-DOF) oscillating cylindrical platform. A buoyancy module of approximately triple the riser diameter was mounted on the one-third of the riser length measured from its base to produce the S-shaped configuration. The VIV response of the flexible riser filled with two typical fluid media, including water and helium, was tested in the depth-averaged reduced velocity ( U ¯ r ) range of 9.32–26.41. The experimental results indicate that the change of internal fluid medium alters the spatial distribution of dominant frequency and excited modal order. The mode competition is enhanced when the internal fluid shifts from water to helium, and the critical U ¯ r for mode transition becomes higher. Based on the coincidence of dominant frequency, four types of coupling response are identified, and two characteristic lengths are quantified. The dominant role of the vibration system is determined by the occurrence time percentages of coupling lengths and dominant frequencies. The vibration of water-filled riser is dominated by itself, and the influence of buoyancy module is negligible. In contrast, the in-plane response of helium-filled riser is significantly affected by the buoyancy module, and the influence is amplified with the increase in U ¯ r . [ABSTRACT FROM AUTHOR]

In this paper, we used the multi-relaxation time lattice Boltzmann method to investigate natural convection in a triangular-shaped cavity filled with a tri-hybrid nanofluid. The cavity is partially heated by a chip of fixed size (l = L / 2), the position of which varies on the left and bottom walls in order to find the optimal positions. The inclined side is maintained at a cool temperature, while the other parts are adiabatic. A detailed analysis is carried out on the impact of four essential parameters on the optimization of heat transfer: the Rayleigh number, ranging between Ra = 103 and Ra = 106; the partial heating position, showing the cavity in six different configurations; the fluid type, including pure water, nanofluid, hybrid nanofluid, and tri-hybrid nanofluid; and finally, the volume concentration of the nanoparticles for three values, ϕ = 0%, 3%, and 6%. Results are presented in the form of isotherms, streamlines, temperature and velocity profiles, and the mean Nusselt number values. As the results show, the position of the partial heater plays a crucial role, influencing natural convection heat transfer significantly in certain positions at all values of the Rayleigh number. The type of fluid has a remarkable impact on the amplification of natural convection at large values of the Rayleigh number, where the buoyancy force becomes strong. Notably, the use of tri-hybrid nanofluid shows a clear improvement in natural convection heat transfer. Furthermore, a substantial increase in thermal transmittance is observed with an increasing nanoparticle volume fraction. The validation results agree well with both numerical results and experimental data published in the literature. [ABSTRACT FROM AUTHOR]

This paper introduces a new variable structure controller designed for depth control of an autonomous underwater sensor platform equipped with a variable buoyancy module. To that end, the prototype linear model is presented, and a finite element-based method is used to estimate one of its parameters, the hull deformation due to pressure. To manage potential internal disturbances like hull deformation or external disturbances like weight changes, a disturbance observer is developed. An analysis of the observer steady-state estimation error in relation to input disturbances and system parameter uncertainties is developed. The locations of the observer poles according to its parameters are also identified. The variable structure controller is developed, keeping energy savings in mind. The proposed controller engages when system dynamics are unfavorable, causing the vehicle to deviate from the desired reference, and disengages when dynamics are favorable, guiding the vehicle toward the target reference. A detailed analysis determines the necessary switching control actions to ensure the system reaches the desired reference. Finally, simulations are run to compare the proposed controller's performance with that of PID-based controllers recently developed in the literature, assessing dynamic response and energy consumption under various operating conditions. Both the VBM- and propeller-actuated vehicles were evaluated. The results demonstrate that the proposed controller achieves an average energy consumption reduction of 22% compared to the next most efficient PID-based controller for the VBM-actuated vehicle, though with some impact on control performance. [ABSTRACT FROM AUTHOR]

This paper presents design method for a tuned liquid damper (TLD) to improve the stability of measurement system based on a spar buoy. Firstly, a TLD was designed utilizing the double-partition hull structure of spar buoy, and the theoretical natural sloshing frequency for this design was calculated. Next, an experimental study was conducted to verify the theoretical calculations. The experimental results showed that the natural sloshing frequency increased with the height of the fluid free-surface, and the values are in close agreement with the theoretical calculations. Finally, the TLD was installed to a free-drifting structure at sea, and the dynamic behavior reduction effect was experimentally verified. The results showed that the behavior of the structure is significantly reduced after the TLD is installed, especially for the behavior above 4 cm. The main contribution of this study is the integration of a TLD into the existing structure of the spar buoy, which enhances stability without compromising buoyancy. However, this approach is limited by the shape and volume constraints of the TLD, making it less effective across all wave-induced frequencies. Further research is required to extend its applicability to a broader range of maritime conditions. [ABSTRACT FROM AUTHOR]

We investigate theoretically the buoyancy-driven motion of a viscous drop in a yield-stress material, incorporating elastic effects represented by the Saramito–Herschel–Bulkley constitutive equation. We solve the governing equations using an open-source finite volume solver and utilizing the volume of fluid technique to accurately capture the interface between the two fluids. To validate our numerical approach, we compare our results with data from previous experimental and numerical studies. We find quantitative agreement in terms of terminal velocities and drop shapes, affirming the accuracy of our model and its numerical solution. Notably, we observe that incorporating elastic effects into the modeling of the continuous phase is essential for predicting phenomena reported in experiments, such as the inversion of the flow field behind the sedimenting drop (i.e., the negative wake) or the formation of a teardrop shape. Due to the elastoviscoplastic nature of the continuous phase, we observe that small drops remain entrapped because the buoyancy force is insufficient to fluidize the surrounding material. We investigate entrapment conditions using two different protocols, which yield different outcomes due to the interplay between capillarity and elastoplasticity. Finally, we conduct an extensive parametric analysis to evaluate the impact of rheological parameters (yield stress, elastic modulus, and interfacial tension) on the dynamics of sedimentation. [ABSTRACT FROM AUTHOR]

The current article has identified dual solutions and their stability for the Ti-alloy/water nanofluid over an exponentially shrinking sheet, while taking into consideration the presence of magnetic fields, radiation and thermal buoyancy forces. The Tiwari and Das model has been utilised to formulate mathematical equations, which have subsequently been transformed from partial differential equations to ordinary differential equations using suitable similarity transformations. The transformed equations have been solved using the shooting method incorporated with the Runge–Kutta technique. Through the application of these techniques, it has been ascertained that multiple solutions have emerged for this problem. To assess the stability of these solutions, the eigenvalue approach has been employed. The eigenvalue approach has revealed that only the first solution is physically viable in laboratory settings, while the second solution is not. The effects of radiation on temperature, skin friction, velocity and heat transfer rate have been elaborated upon in detail. Furthermore, flow separation points have been identified and the rationale behind the delay in flow separation has been expounded upon. Streamlined patterns have been drawn and explained to enhance our understanding of the fluid flow behaviour. Finally, it is worth noting that these types of studies have significant applications in the medical and aerospace industries. [ABSTRACT FROM AUTHOR]

Upwelling along the western boundary of the major ocean basin subtropical gyres has been diagnosed in a wide range of ocean models and state estimates. This vertical transport is O(5 × 106) m3 s−1, which is on the same order of magnitude as the downward Ekman pumping across the subtropical gyres and zonally integrated meridional overturning circulation. Two approaches are used here to understand the reason for this upwelling and how it depends on oceanic parameters. First, a kinematic model that imposes a density gradient along the western boundary demonstrates that there must be upwelling with a maximum vertical transport at middepths in order to maintain geostrophic balance in the western boundary current. The second approach considers the vorticity budget near the western boundary in an idealized primitive equation model of the wind- and buoyancy-forced subtropical and subpolar gyres. It is shown that a pressure gradient along the western boundary results in bottom pressure torque that injects vorticity into the fluid. This is balanced on the boundary by lateral viscous fluxes that redistribute this vorticity across the boundary current. The viscous fluxes in the interior are balanced primarily by the vertical stretching of planetary vorticity, giving rise to upwelling within the boundary current. This process is found to be nearly adiabatic. Nonlinear terms and advection of planetary vorticity are also important locally but are not the ultimate drivers of the upwelling. Additional numerical model calculations demonstrate that the upwelling is a nonlocal consequence of buoyancy loss at high latitudes and thus represents an integral component of the meridional overturning circulation in depth space but not in density space. Significance Statement: The purpose of this study is to better understand what is forcing water to upwell along the western boundary at midlatitudes of the major ocean basins. This is a potentially important process since upwelling can bring heat and nutrients closer to the surface, where they can be exchanged with the atmosphere. Also, since ocean currents vary with depth, pathways followed in the upper ocean are different from those found for the deeper ocean, so the amount and location of upwelling influence where these waters go. Idealized numerical models and theory are used to demonstrate that the upwelling is ultimately driven by density changes along the western boundary of the basin that result from heat loss at high latitudes. [ABSTRACT FROM AUTHOR]

We investigate the mechanism for eye formation in hurricane-like vortices, using a formulation adapted from Oruba, Davidson, and Dormy. Numerical simulations are performed using an axisymmetric model of dry rotating Rayleigh–Bénard convection under the Boussinesq approximation. The fluxes of heat and momentum at the sea surface are described using the bulk aerodynamic formula. A simplified model for radiative cooling is also implemented. We find that the mechanism for eye formation introduced in Oruba et al., relying on vorticity stripping from the boundary layer, is robust in dry hurricane-like vortices. Furthermore, with these boundary conditions, the structure of the flow is closer to the flow of actual tropical cyclones. The applicability of this mechanism to the moist case however remains uncertain and deserves further study. Finally, energy budgets, obtained either by a heat engine approach or by a direct estimation of the work of buoyancy forces, are investigated. They provide estimations of the surface wind speed as a function of the controlling parameters. Significance Statement: Tropical cyclones (also known as hurricanes or typhoons, depending on their location) are life-threatening and devastating atmospheric vortices. Their impact worsens with sea level rise and increasing coastal population. Here, we explore, using idealized models, the physics behind the formation of an eye (the quiet and typically clear region at the center of these storms). We then investigate the controlling parameters for the amplitude of the strongest winds in the model, using energy constraints, and compare them to what is observed in actual tropical cyclones. [ABSTRACT FROM AUTHOR]

The present study focuses on the MHD Radiative Casson fluid flow with the effect of triple diffusivity over a vertical porous wall along with convective boundary conditions. The governing equations for detecting the nature of the fluid under the influence of solutal diffusivity and thermal conductivity in triple diffusive boundary layer flow are derived. Non-linear partial differential equations are reduced to ordinary differential equations via similarity transformation. The BVP4C method in MATLAB software is then used to solve them. The outcomes of several physical dimensionless parameters like permeability, convective parameter, buoyancy ratio parameter, Casson parameter and chemical reaction parameter with source/sink impacts established by graphics. Also, the impression of the local skin friction coefficient, Nusselt number, and local Sherwood number are presented through the tables. [ABSTRACT FROM AUTHOR]

This study considers in depth the flow of the boundary layer of an incompressible, viscous, and steady Casson fluid through an expanding surface when thermal radiation, heat source, Soret, and Dufour effects are present. Using suitable similarity transformations, the governing non-linear partial differential equations are converted into coupled ordinary differential equations and then estimated using the MATLAB software bvp4c using a shooting process. Variable values of the parameters employed in the current inquiry are offered, together with solutions for the parameters of momentum, temperature, concentration, coefficient of local skin friction, and local Nusselt number. It is observed that the Casson fluid parameter improves fluid velocity and decreases the temperature. Also, it is found that thermal radiation and the presence of a heat source/sink increase the temperature of the fluid. We compared the present investigation with previously published papers and found them harmonious. [ABSTRACT FROM AUTHOR]

We explore the stability of floating objects at a two-fluid interface through mathematical modeling and experimentation. Our models are based on standard ideas of center of gravity, center of buoyancy, and Archimedes' Principle extended to the two-fluid scenario. We investigate floating shapes with uniform, two-dimensional cross sections and identify analytically and/or computationally a potential energy landscape that helps identify stable and unstable floating orientations. We compare our analyses and computations to experiments on floating objects designed and created through 3D printing. Additionally, the paper includes open problems for further study. [ABSTRACT FROM AUTHOR]

This article proclaims Casson-Williamson fluid's buoyancy assisting and opposing flow through a vertical stretching sheet. The flow is intended to be two-dimensional, unsteady, and laminar by examining the viscous dissipation, Joule heating, and cross-diffusion effects. Further, this study is performed under thermal radiation, Brownian motion, and thermophoresis effects. The mathematical model is developed by considering the combined characteristics of the Casson and Williamson fluid model. Developed mathematical model is simplified using competent similarity variables, and the acquired system of an ordinary differential equation is operated with BVP Midrich method. Finally, graphical results are produced for momentum, thermal, and mass profile in both buoyancy assisting and buoyancy opposing flow cases. Impact of all emerging variables on local skin friction coefficient, Nusselt, and Sherwood numbers is illustrated through numerical data in table format. [ABSTRACT FROM AUTHOR]

This study examines the effect of heat production and radiation absorption on the magnetohydrodynamic Casson fluid flow at the stagnation point in a porous medium. We convert the group of fluid flow equations, which are non-linear partial differential equations with suitable boundary constraints, into a set of non-linear ordinary differential equations using similarity transformations. The homotopy analysis method (HAM) solves the converted system of ordinary differential equations. We draw graphs for numerous values of non-dimensional parameters and tables of surface drag force, rates of heat transfer, and mass transfer to analyze the relationship between velocity field, temperature field, concentration field, and other essential parameters involved in the study. We have proven that the Dufour number, radiation parameter, and heat generation parameter elevate the fluid temperature, whereas the magnetic parameter lowers it. The Casson fluid parameter, buoyancy force parameter, and mixed convection parameter all promote fluid movement throughout the flow field. The presented tabular data allows us to see the trend of heat and mass transfer rates, as well as drag force rates, against important parameters, enhancing our understanding of these rates. [ABSTRACT FROM AUTHOR]

Second/foreign language (L2) writing emotions play an important role in language writing outcomes. However, extant literature was dominated by L2 anxiety with other types of emotions being neglected. Further, little is known about whether English-as-a-foreign-language (EFL) writers demonstrate heterogenous patterns of emotional experiences in English writing. The aim of the study was to identify intra-individual differences in EFL writing emotion patterns and how these patterns differed from each other in terms of writing buoyancy, motivation, and proficiency. Through convenience sampling, three hundred and sixty-three EFL undergraduates in China were recruited and they completed a battery of questionnaires. Latent profile analysis (LPA) revealed a three-profile solution. They were labelled as the "positive type" (PT), "negative type" (NT) and "moderate type" (MT). Three groups reported significantly different levels of writing buoyancy and motivation with the highest scores of them being found among the PT group, followed by MT, and lastly NT. The writing proficiency was higher for the PT group than for the NT group, but the PT group did not differ from the NT or MT group. The dominance of MT group suggested that most students exhibited mild attitudes toward EFL writing. The distinct patterns of EFL writing emotions and their influences on writing outcomes suggested that teachers should boost students' emotional learning competence and adjust the teaching approach accordingly. [ABSTRACT FROM AUTHOR]

The dispersal of large river plumes in the coastal ocean depends on multiple factors, and in some cases, can be categorized into distinct dynamical regimes: a tidally dominated near‐field, a rotational mid‐field, and a coastal current far‐field. In this study, observations and modeling are used to evaluate the factors controlling the variability in the buoyant plume from Mobile Bay. Rather than distinct dynamical regimes, the Mobile Bay plume depends on forcings that act at overlapping temporal and spatial scales: diurnal tides, river discharge events, and winds. Satellite synthetic aperture radar images along with shipboard in‐situ sampling and marine radar are used to observe plume fronts in spring 2021. Hydrodynamic model simulations are compared with observations and used to characterize a large coastal plume at consistent tidal phase across a range of forcing conditions. The along‐shore position of the plume depends primarily on advection by wind‐driven surface currents. The cross‐shore extent and plume area depend primarily on the tidal amplitude and river discharge, and secondarily on northerly (seaward) winds. Along‐shore winds influence the buoyancy anomaly by altering salinity in the estuary and offshore. Upwelling winds increase the buoyancy anomaly and advect previous plumes away from the mouth. Downwelling winds reduce the buoyancy anomaly by trapping previous plumes near the coast and directing freshwater discharge toward a secondary outlet. Thus, the combined, overlapping influences of the tide, wind, and discharge dominate the variability in freshwater delivery to the shelf at time scales of days and distances of tens of km. Plain Language Summary: Buoyant river plumes discharge into the coastal ocean and alter the distribution of freshwater and material like sediment and nutrients. This study examines the factors affecting the plume from Mobile Bay in the Gulf of Mexico. The research integrates shipboard measurements, satellite imagery, and numerical modeling to capture the variability in the plume in spring 2021. Plumes are often characterized with distinct regions where particular physical processes dominate—the tide or river discharge close to the mouth, and the earth's rotation and wind as the plume spreads and transitions into a coastal current. However, for Mobile Bay the winds, tides, and river discharge all contribute significantly to the size and position of the plume. Along‐shore winds drive coastal currents that transport the plume, upwelling or downwelling winds move the plume offshore or trap it near the coast, and shallow stratification increases the direct influence of the wind. Diurnal tides drive outflows that are much larger than the scale of influence of the earth's rotation, and river discharge varies substantially with meteorological events. The influences of the wind, tides and discharge cannot be cleanly separated in determining the fate of outflow from Mobile Bay and similar systems. Key Points: Diurnal tides, river discharge, and winds all contribute substantially to determining the size and location of the Mobile Bay plumeAlong‐shore winds advect the plume and influence the buoyancy anomaly through upwelling/downwelling and the freshwater outflow distributionResponse of the plume to forcing at tidal‐to‐meteorological time scales inhibits formation of a bulge and geostrophic coastal current [ABSTRACT FROM AUTHOR]

Abstract In contrast to expectations, even buoyant microplastics like polyethylene and polypropylene are found at high concentrations in deep sediment traps and deep-sea sediments. To explain the presence of such buoyant microplastic particles at great ocean depths, several vertical transport mechanisms are under discussion with biofouling as one of the most referred. Biofouling is thought to increase the density of microplastic particles to the point that they sink to the deep sea, but this has mostly been shown on large microplastic particles ≥ 1 mm. However, although microplastics are defined as particles between 1 and 5000 μm, most microplastics are