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Tropical instability waves (TIWs) are identified in three multiyear equatorial mooring records in Pacific and Atlantic cold tongues to evaluate how TIWs modulate turbulence. At 0°, 140°W in the Pacific, TIWs are present in 43% of observations, and are associated with elevated vertical shear and a 40% average increase in turbulence dissipation rates (ϵ) above the Equatorial Undercurrent. Zonal shear is greatest when currents are southward while buoyancy is greatest later in the TIW cycle, leading to greater potential for instability and elevated turbulence before and during the southward flow maximum. This suggests that TIW vortex stretching contributes to enhanced shear and turbulence. In the Atlantic, TIWs are found in 38% of observations at 0°, 23° W and 16% of observations at 0°, 10°W. TIWs at 23°W increase ϵ by 18% where turbulence is likely modulated by vortex stretching and, near the surface, by the seasonally wind‐forced equatorial roll. At 23°W and 140°W, TIWs with strong meridional velocity fluctuations are associated with the strongest turbulence. Contributions of seasonal variations are removed by considering only periods when TIWs are climatically active. During these periods, mean values of ϵ in the presence of strong TIWs are elevated by 61% at 140°W, 29% at 23°W, and 36% at 10°W. At 10°W, where our identification scheme may include wind‐forced oscillations in the same frequency band, increases in ϵ are not consistent in the presence of TIWs and do not contribute significantly to multiyear averages. [ABSTRACT FROM AUTHOR]

Macrosegregation and coarse primary carbides caused by microsegregation are typical solidification defects during Vacuum Arc Remelting (VAR) which greatly limit the mechanical properties of M50-bearing steel components. A solid-liquid Eulerian two-phase model that describes solidification behaviors at both macro and micro scales is developed to predict macrosegregation of M50 ingots under a complex multi-physics condition. A good match is observed between the simulated results and experimental data. The segregation pattern of carbon is predicted with and without natural convection. Compared with thermal-solutal buoyancy, the Lorentz force is stronger and regarded as the main driving force for macrosegregation formation. The flows generated by thermal-solutal buoyancy and Lorentz force are in opposite directions. The natural convection flowing downward along solidification front leads to more serious positive segregation at the center of ingot. The uniformity of concentration distribution is improved with the increase of ingot diameter. The main reason is that the increase of diameter leads to the decrease of current density, and further decreases the Lorentz force, thus weakening the fluid flow. For the first time, an analytical formula of the equivalent size of primary carbides in M50 steel is established. It is found that the size of carbides in large-diameter industrial VAR-ingot is larger. The present work provides new insights for co-operative controlling the macro and micro segregations and the size of carbides in VAR ingots. The optimal ingot size with a diameter of 280 mm is found. [ABSTRACT FROM AUTHOR]

We investigated academic buoyancy—and its predictors and outcomes—among female students attending all-girls and coeducational schools. We examined data from 1,254 female students. Structural equation modeling revealed that students' perceptions of three instructional climate factors (teacher-student relationships, useful content, engaging content) were positively associated with their learning strategies (elaboration, memorization, control) and achievement and, in turn, academic buoyancy (assessed one year later) in similar ways across the two school types. In turn, learning strategies, achievement, and academic buoyancy were associated with academic, well-being, and occupational outcomes assessed up to age 22 in different ways. Together, the findings provide understanding about academic buoyancy among girls, provide guidance for how teachers can support buoyancy and other personal attributes among girls, and yield knowledge about the longer-term outcomes of academic buoyancy. [ABSTRACT FROM AUTHOR]

Incorporation of momentum gradients produced due to inertial motion of the lid along with the presence of temperature differences in the configuration make the physical problem more significant. The joint variation of momentum and thermal diffusion in diversified natural liquids is recognized as mixed convection. Valuable attention has been received by such a phenomenon in different areas of science and technology such as in wind current --based solar receivers, electronic instruments, control of emergency shutdown in reactors, thermal exchangers, oceanic currents, control of atmospheric pollution, and so on. So, the main focus is to contemplate hydrothermal characteristics of a power-law fluid contained in a square cavity with themovement of the upper lid and being thermally adiabatic. The other extremities are considered to be at rest, and the base wall is prescribed with uniform/nonuniform temperature distributions. The governing formulation of the problem is handled by executing a finite element approach. Hybrid meshing is performed for domain discretization, and weak variational formulation is utilized for formulation discretization. Second-degree polynomials are employed as the interpolation function, providing information about velocity and temperature distributions at boundary and intermediate nodes. The system of finalized non-linear equations is resolved by using the Paradiso software. The results for velocity and temperature distributions are attained comparatively for uniformly and non-uniformly heated profiles. The kinetic energy and average Nusselt number are also computed against flow concerning variables. From the attained graphical and tabular data, it is deduced that by increasing the Reynolds number, inertial forces dominate over buoyancy forces and the effect of lid movement is prominent on flow characteristics. It is also inferred that for the shear thickening case and for all values of the Reynolds number, the average Nusselt number shows a constant behavior. [ABSTRACT FROM AUTHOR]

The effect of triple diffusion on convection of viscous liquid in a vertical channel saturated with permeable material is explored subject to Robin conditions on the boundaries. Inside the duct, the salts of distinct compositions are diffused. Non‐Darcy approach is used to describe the porous material influence on transport processes. Symmetric and asymmetric heating conditions are considered for the ambient temperatures close to the vertical channel borders. Heat is exchanged between the vertical plates and the external fluid. Initially, the solutions are found without an influence of viscous dissipation and buoyancy forces. Inclusion of these two effects leads to nonlinear equations and adopting Brinkman parameter as the perturbation characteristic for the solutions is procured. Owing to the limitation on the perturbation characteristic, the conservation relations are solved numerically using the Runge–Kutta procedure combined with shooting technique. The flow patterns are depicted for the properties of the heat and mass Grashof numbers, porous parameter, inertial parameter, Brinkman number, Biot numbers, and chemical reaction characteristics. The effects of these parameters are explored on the skin frictions and Nusselt numbers. In the case of dissipations caused by viscosity and Forchheimer drag term, the perturbation results and numerical solutions are equal for low magnitudes of perturbation characteristic. [ABSTRACT FROM AUTHOR]

It is enigmatic that M8+ earthquakes can take place at depth greater than 600 km inside the slab, where the P-T conditions generally do not favor seismic slip rate (~m/s) on faults. Here we provide fresh insights to the initial rupture and mechanism of the Mw 8.3 Sea of Okhotsk earthquake by analyzing high-frequency (up to 0.8 Hz) teleseismic array data. We determine the relative location and timing of two early subevents, and the geometry and velocity perturbation of a nearby structure anomaly. We found a small-scale (~30 × 60 × 60 km) ultralow (−18 ± 2%) P-wave velocity anomaly located beneath the Pacific slab around the 660 km discontinuity. The volatile-bearing highly melted nature of the anomaly provides significant buoyancy, stressing the slab dramatically closer to the critical condition for thermal runaway weakening that allows the rupture to propagate beyond the metastable olivine wedge, forming M8+ events. Enormous velocity reduction urges for further mineral physics and geodynamic investigations. A small ultralow velocity anomaly has been identified between the Pacific subduction and upper-lower mantle boundary. This anomaly implies significant buoyancy, which may bring the slab easier to develop into a M8+ deep earthquake. [ABSTRACT FROM AUTHOR]

The mixed convection and electrically conducting flow of two-dimensional Williamson fluid across a nonlinear stretched curvy sheet in the presence of suction/injection, variable thermal conductivity, heat sink/source, and activation energy with convective boundary conditions are discussed in this article. A system of nonlinear PDEs is converted to a system of nonlinear ODEs using similarity transformations. Instead of focusing on the local effect of the Williamson fluid parameter λ , this study looks at the global impact. Using graphs, we examine how suction/injection, variable thermal conductivity, heat sink/source, and activation energy affect the resulting velocity, temperature, pressure, and concentration profiles. Physical quantities of interest to engineers are tabulated as well, including the skin friction coefficient, Nusselt number, and Sherwood number. Both thermal and mass buoyancy force parameters directly correlate with thermal and concentration profiles. This study plays an imperative role in biological and chemical engineering. [ABSTRACT FROM AUTHOR]

Dansgaard-Oeschger (DO) events are a pervasive feature of glacial climates. It is widely accepted that the associated changes in climate, which are most pronounced in the North Atlantic region, are caused by abrupt changes in the strength and/or latitude reach of the Atlantic meridional overturning circulation (AMOC), possibly originating from spontaneous transitions in the ocean-sea-ice-atmosphere system. Here we use an Earth System Model that produces DO-like events to show that the climate conditions under which millennial-scale AMOC variations occur are controlled by the surface ocean buoyancy flux. In particular, we find that the present day-like convection pattern with deep water formation in the Labrador and Nordic Seas becomes unstable when the buoyancy flux integrated over the northern North Atlantic turns from negative to positive. It is in the proximity of this point that the model produces transitions between different convection patterns associated with strong and weak AMOC states. The buoyancy flux depends on the surface freshwater and heat fluxes and on sea surface temperature through the temperature dependence of the thermal expansion coefficient of seawater. We find that larger ice sheets tend to stabilize convection by decreasing the net freshwater flux while CO2-induced cooling decreases buoyancy loss and destabilizes convection. These results help to explain the conditions under which DO events appear, and are a step towards an improved understanding of the mechanisms of abrupt climate changes. [ABSTRACT FROM AUTHOR]

Direct numerical simulations are utilised to investigate mass-transfer processes at gas-evolving electrodes that experience successive formation and detachment of bubbles. The gas-liquid interface is modelled employing an immersed boundary method. We simulate the growth phase of the bubbles followed by their departure from the electrode surface in order to study the mixing induced by these processes. We find that the growth of the bubbles switches from a diffusion-limited mode at low to moderate fractional bubble coverages of the electrode to a reaction-limited growth dynamics at high coverages. Furthermore, our results indicate that the net transport within the system is governed by the effective buoyancy driving induced by the rising bubbles and that mechanisms commonly subsumed under the term 'microconvection' do not significantly affect the mass transport. Consequently, the resulting gas transport for different bubble sizes, current densities and electrode coverages can be collapsed onto one single curve and only depends on an effective Grashof number. The same holds for the mixing of the electrolyte when additionally taking the effect of surface blockage by attached bubbles into account. For the gas transport to the bubble, we find that the relevant Sherwood numbers also collapse onto a single curve when accounting for the driving force of bubble growth, incorporated in an effective Jakob number. Finally, linking the hydrogen transfer rates at the electrode and the bubble interface, an approximate correlation for the gas-evolution efficiency has been established. Taken together, these findings enable us to deduce parametrisations for all response parameters of the systems. [ABSTRACT FROM AUTHOR]

The seasonal and spatial evolution of the mixed layer (ML) in the Red Sea (RS) and the influence of atmospheric buoyancy and momentum forcing are analyzed for the 2001–2015 period using a high-resolution (1/100°, 50 vertical layers) ocean circulation model. The simulation reveals a strong spatiotemporal variability reflecting the complex patterns associated with the air–sea buoyancy flux and wind forcing, as well as the significant impact of the basin’s general and mesoscale circulation. During the spring and summer months, buoyancy forcing intensifies stratification, resulting in a generally shallow ML throughout the basin. Nevertheless, the results reveal local maxima associated with the influence of mesoscale circulation and regular wind induced mixing. Under the influence of surface buoyancy loss, the process of deepening of the ML commences in early September, reaching its maximum depth in January and February. The northern Gulf of Aqaba and the western parts of the northern RS, exhibit the deepest ML, with a gradual shoaling toward the south, primarily due to the surface advection of relatively fresh water that enters the basin from the Gulf of Aden. The mixed layer depth (MLD) variability is primarily driven by atmospheric buoyancy forcing, especially its heat flux component. Although evaporative fluxes dominate the annually averaged surface buoyancy forcing, they exhibit weak seasonal and spatial variability. Wind induced mixing exerts a significant impact on the MLD only locally, especially during summer. Of particular importance are strong winds channeled by topography, such as those in the vicinity of the Strait of Bab-Al-Mandeb and the straits connecting the two gulfs in the north, as well as lateral jets venting through mountain gaps, such as the Tokar Jet in the central RS. The analysis highlights the complex patterns of air-sea interactions, thermohaline circulation, and mesoscale activity, all of them strongly imprinted on the MLD distribution. [ABSTRACT FROM AUTHOR]

We present the results from a series of experiments investigating the dynamics of gravity currents which form when a dense saline or particle-laden plume issuing from a moving source interacts with a horizontal surface. We define the dimensionless parameter P as the ratio of the source speed, ua, to the buoyancy speed, (B0/z0)1/3, where B0 and z0 are the source buoyancy flux and height above the horizontal surface, respectively. Using our experimental data, we determine that the limiting case in which P = Pc the gravity current only spreads downstream of the initial impact point occurs when Pc = 0.83 ± 0.02. For P < Pc, from our experiments we observe that the plume forms a gravity current that spreads out in all directions from the point of impact and the propagation of the gravity current is analogous to a classical constant-flux gravity current. For P > Pc, we observe that the descending plume is bent over and develops a pair of counter-rotating line vortices along the axis of the plume. The ensuing gravity current spreads out downstream of the source, normal to the motion of the source. Analogous processes occur with particle-laden plumes, but there is a second dimensionless parameter S, the ratio of the particle fall speed, vs, to the vertical speed of a plume in a crossflow, (B0/uaz0)1/2. For S x 1, particles remain well mixed in the plume and a particle-driven gravity current develops. For S x 1, particles separate from the plume prior to impacting the boundary which leads to a fall deposit and no gravity current. We discuss these results in the context of deep-sea mining. [ABSTRACT FROM AUTHOR]

The present work focuses on the effect of rough horizontal boundaries on the heat transfer in rotating Rayleigh-Bénard convection. We measure the non-dimensional heat transfer, the Nusselt number Nu, for various strengths of the buoyancy forcing characterized by the Rayleigh number Ra (105 <~ Ra <~ 5 × 108), and rotation rates characterized by the Ekman number E (1.4 × 10-5 <~ E <~ 7.6 × 10-4) for aspect ratios G = 1, 2.8 and 6.7. Similar to rotating convection with smooth horizontal boundaries, the so-called rotationally constrained (RC), rotation-affected (RA) and rotation-unaffected (RuA) regimes of heat transfer seem to persist for rough horizontal boundaries. However, the transition from the RC regime to RA regime occurs at a lower Rayleigh number for rough boundaries. For all experiments with rough boundaries in this study, the thermal and Ekman boundary layers are in a perturbed state, leading to a significant enhancement in the heat transfer as compared with that for smooth walls. However, the enhancement in heat transfer due to wall roughness is observed to attain a maximum in the RC regime. We perform companion direct numerical simulations of rotating convection over smooth walls to suggest a phenomenology explaining this observation. We propose that the heat transfer enhancement due to wall roughness reaches a maximum when the strength and coherence of the columnar structures are both significant, which enables efficient vertical transport of the additional thermal anomalies generated by the roughness at the top and bottom walls. [ABSTRACT FROM AUTHOR]

Academic buoyancy has a significant and stable effect on adolescent academic achievement. Thus, it is vital to examine the antecedent variables of academic buoyancy. However, little research has examined the effect of body image dissatisfaction on academic buoyancy. This study investigates the link between body image dissatisfaction and academic buoyancy in Chinese adolescents, focusing on the mediating roles of social anxiety and basic psychological needs satisfaction. Using the Negative Physical Self Scale, the Social Anxiety Scale for Adolescents, the Basic Psychological Needs Satisfaction Scale, and the Academic Buoyancy Scale, questionnaires were administered to 516 high school students in Henan and Hunan provinces in China. The results revealed that: (1) basic psychological needs satisfaction mediated the relationship between body image dissatisfaction and academic buoyancy among Chinese adolescents; (2) social anxiety and basic psychological needs satisfaction had a serial mediating role between body image dissatisfaction and academic buoyancy among Chinese adolescents. This research provides a pioneering exploration of the effect of body image dissatisfaction on academic buoyancy and its mechanisms. Implications for secondary school education practices and directions for future research are discussed. Practitioner points: Body image dissatisfaction predicted academic buoyancy.Basic psychological needs satisfaction mediated the relationship between body image dissatisfaction and academic buoyancy.Social anxiety and basic psychological needs satisfaction play a serial mediating role in the relationship between body image dissatisfaction and academic buoyancy. [ABSTRACT FROM AUTHOR]

In this paper, the convective boundary layer flow that evolves on the external surface of a heated horizontal cylinder is investigated with the scaling analysis. Two thermal boundary conditions at the heated surface are considered: an isothermal and an iso-flux heating condition. The calculated data demonstrate that, similar to the extensively studied flat-plate boundary layer flows, development of the present curved boundary layer also consists of three states, i.e., an initial growth, a transitional state and a steady state. Scale laws of the characteristic velocity and thickness describing the initial and steady states are determined based on the calculated cases. The results show that unlike flat-plate boundary layers, the present characteristic velocity depends on both time and streamwise location and therefore the curved boundary layer flow follows a two-dimensional startup. The obtained scale law also indicates that the maximum characteristic velocity in the initial state is symmetrical about θ = π /2 as it is caused by the tangential component of the buoyancy force. In the steady state, the characteristic velocity occurs at approximately θ = 7 π /9 and we show that this value is independent of the governing parameters. Comparison between the proposed scale laws and the calculated cases suggests that the regression constants R 2 are above 0.995. Hence, the obtained scale laws could appropriately quantify the present curved boundary layer flow. [ABSTRACT FROM AUTHOR]

Due to the high computational costs of the Eulerian multiphase model, which solves the conservation equations for each considered phase, a two-phase mixture model is proposed to reduce these costs in the current study. Only one single equation for each the momentum and enthalpy equations has to be solved for the mixture phase. The Navier–Stokes and energy equations were solved using the 3D finite volume method. The model was used to simulate the liquid–solid phase transformation of a Fe-0.82wt%C steel alloy under the effect of both thermocapillary and buoyancy convections. The alloy was cooled in a rectangular ingot (100 × 100 × 10 mm3) from the bottom cold surface to the top hot free surface by applying a heat transfer coefficient of h = 600 W/m2/K, which allows for heat exchange with the outer medium. The purpose of this work is to study the effect of the surface tension on the flow and segregation patterns. The results before solidification show that Marangoni flow was formed at the free surface of the molten alloy, extending into the liquid depth and creating polygonized hexagonal patterns. The size and the number of these hexagons were found to be dependent on the Marangoni number, where the number of convective cells increases with the increase in the Marangoni number. During solidification, the solid front grew in a concave morphology, as the centers of the cells were hotter; a macro-segregation pattern with hexagonal cells was formed, which was analogous to the hexagonal flow cells generated by the Marangoni effect. After full solidification, the segregation was found to be in perfect hexagonal shapes with a strong compositional variation at the free surface. This study illuminates the crucial role of surface-tension-driven Marangoni flow in producing hexagonal patterns before and during the solidification process and provides valuable insights into the complex interplay between the Marangoni flow, buoyancy convection, and solidification phenomena. [ABSTRACT FROM AUTHOR]

There are indications that spatially inhomogeneous buoyancy forces can play a signifi cant role in the dynamics of intense tornado-type atmospheric vortices. The paper considers a linearized model of disturbances caused by buoyancy deviations (in particular, inhomogeneously distributed heavy impurity) in an intense vortex with a vertical axis. Analytical relations allowing assessment of the amplitude of perturbations of velocity and pressure have been obtained. [ABSTRACT FROM AUTHOR]

In the western tropical Atlantic Ocean close to the Amazon plume, a large loss rate of Argo-float profiles took place, that is, instances of profiles that should have happened but were not transmitted. We find that APEX and SOLO floats were not ascending to the surface in the presence of low surface practical salinity, typically on the order of 32.5 or less, because of limitations on the surface buoyancy range for those floats. This results in an overall loss of profiles from these floats that is on the order of 6% averaged over the year, with a peak of 12% in July. We also find aborted descents/incorrect grounding detections for ARVOR/PROVOR floats when surface salinity is low and the descending float reaches a strong halocline (2.6% of all the profiles in the June–August season). Altogether, the whole Argo set includes a maximum loss rate of roughly 6% in July. We find a pattern of loss that fits the surface salinity seasonal cycle and the occurrence of low surface salinity investigated from a high-resolution daily satellite salinity product in 2010–21. The agreement is even better when considering surface density instead of surface salinity, with the temperature contribution to density inducing a shift in the maximum occurrence of these events by 1 month relative to the cycle of very low salinity events. Because of changes in the float technology, the loss rate that targets the lowest surface salinities was very large until 2010, with an overall decrease afterward. Significance Statement: In the western tropical Atlantic Ocean, some Argo floats were not able to ascend or descend with very low surface salinity, because of buoyancy limitations for some float types and false bottom detection on others. In this region, for surface practical salinity smaller than 32.5, this resulted in a loss of close to one-half of the Argo profiles during the last 20 years. Altogether, this undersampling of the lowest surface salinities by Argo floats modifies the upper-ocean salinity seasonal cycle, as well as longer-term trends portrayed in Argo data–based products. Furthermore, in this region, care must be taken when validating satellite salinity data with Argo data or when adjusting satellite sea surface salinity data to in situ data products. [ABSTRACT FROM AUTHOR]

Based on a submesoscale-resolving glider observation from April 25 to May 4, 2018, characteristics and underlying dynamics of submesoscale variability at the edge of an anticyclonic eddy shed from Kuroshio in the Northern South China Sea are explored in this study. Three underwater gliders traveled across the frontal zone and implemented ~ 300 dives, covering a horizontal distance of ~ 160 km and a vertical depth of ~ 500 m in 9 days. The character of k−2 slope for spectral potential energy and the strong lateral buoyancy gradient indicate frontogenesis-induced submesoscale motions on the eddy edge. Further analysis focusing on the potential vorticity and balanced Richardson number reveals the development of symmetric instability (SI), which is associated with the strong lateral gradient of buoyancy at the edge of the anticyclonic eddy in the late spring. [ABSTRACT FROM AUTHOR]

Dyke propagation is a mechanism for more rapid ascent of felsic magmas through the crust than is possible via diapirs or percolative flow. As it ascends, the magma undergoes complex physical and chemical transformations induced by decompression and cooling. These processes dramatically change the magma density and viscosity, which in turn affect magma ascent rate and the depth at which the dyke arrests. We present a mathematical model of dyke propagation for silicic magmas taking into account the presence of multiple volatile species (H2O and CO2), bubble growth, heat advection and loss, crystallization and latent heat release. We consider conditions for dykes associated with porphyry ore deposits, which may represent an end-member in rapid ascent of felsic magmas from depth. In particular, we simulate the propagation of dykes launched from a deep (900 MPa), volatile-saturated magma source, testing the effects of the magma H2O/CO2 content, temperature and mass on its ascent rate and final emplacement depth. The model predicts short ascent times (hours to days), with a large increase in viscosity at shallow depth, leading to stagnation and solidification of the dyke. Higher initial water content, higher temperature and larger mass of the magma in the dyke promote faster propagation and shallower arrest. Volatile loss from ascending magma remains limited until the stagnation depth, providing a potential mechanism for transfer of deep volatiles to hypabyssal blind intrusions associated with porphyry ore deposits. Our findings are applicable to the problem of silicic magma ascent through the crust more generally. [ABSTRACT FROM AUTHOR]

This study investigates time-dependent free convection heat transfer and buoyancy-assisted flow over a horizontal heated plate within a vertical channel for two distinct scenarios: one stand alone and second involving tilted plates and varying plate positions. The temperature difference between the plate and air induces buoyant airflow. The study explores the impact of plate tilt angles and positions on time-dependent heat transfer coefficients due to varying buoyant airflow. The primary focus of the research for both classes of study is on the effects of the tilt angles (which control the change in flow blockage ratio) and positions of the heated plate on the time-dependent heat transfer coefficients due to the time-dependent buoyant airflow. As the blockage ratio increases and the positions of the heated plate in the vertical channel decreases, the influence of time-dependent buoyancy on the time-dependent Nusselt number weakens. The time-dependent Richardson's number varied from 7.4 to 9.6 throughout the tests. Based on the experimental data gathered from corresponding flux geometries and test conditions, the CFD model was validated. We have also developed a set of empirical correlations for predicting time-dependent Nusselt numbers for a time-dependent Rayleigh number range of 2000 < Ra < 7500, the dimensionless height of the heated plate from 0.507 ≤ ϕ ≤ 0.551, and a flow blockage ratio of 0.08 ≤ χ ≤ 0.024. At orientations where γ = π/2 and γ = π/4, it has been observed that the heat transfer at position ∅ 1 is higher, whereas at γ = 0 orientation, ∅ 1 heat transfer value is lower compared to the others. When the time required for the heated plate at all positions (∅) to reach thermal equilibrium with the ambient environment is compared with respect to orientation angles, it has been observed that the γ = π/2 orientation angle reaches thermal equilibrium in the shortest time compared to the γ = π/0 and γ = π/4 orientation angles. [ABSTRACT FROM AUTHOR]

The improved thermal assessment of nano‐particles in presence of magnetic force, thermal radiation and activation energy involve dynamic applications in thermal engineering, industrial processes, and modern technologies. The bioconvection pattern in various nanoparticles attributes novel bio‐technology applications like bio‐fuels petroleum engineering, enzymes, bio‐sensors, and many more. On this end, present theoretical analysis endeavors to examine the thermal characteristics of time dependent Williamson nanofluid confined by an unsteady stretched radioactive Riga plate. Here, nanofluid bioconvection is developed by the combined aspects of buoyancy forces and magnetic field with collaboration of motile microorganisms and nanoparticles. Present analysis is further carried out in presence of activation energy, nonlinear thermal radiation and chemical reaction. The whole exploration is exposed to convective Nield constraints on boundary. The dimensionless form of formulated nonlinear system is achieved with utilization of apposite transformations and then approximate solution is elucidated by shooting technique. The graphical interpretation for numerous relevant parameters on velocity, concentration, temperature and motile microorganism profiles are displayed. The results reveal that an increasing variation in velocity is noticed with modified Hartmann. An increasing nanofluid temperature is associated with Williamson parameter and temperature ratio constant. Moreover, the motile microorganism distribution enhances with bioconvected Lewis and mixed convection constant. [ABSTRACT FROM AUTHOR]

Mechanical forcing by orography affects precipitating convection across many tropical regions, but controls on the intensity and horizontal extent of the orographic precipitation peak and rain shadow remain poorly understood. A recent theory explains this control of precipitation as arising from modulation of lower-tropospheric temperature and moisture by orographic mechanical forcing, setting the distribution of convective rainfall by controlling parcel buoyancy. Using satellite and reanalysis data, we evaluate this theory by investigating spatiotemporal precipitation variations in six mountainous tropical regions spanning South and Southeast Asia, and the Maritime Continent. We show that a strong relationship holds in these regions between daily precipitation and a measure of convective plume buoyancy. This measure depends on boundary layer thermodynamic properties and lower-free-tropospheric moisture and temperature. Consistent with the theory, temporal variations in lower-free-tropospheric temperature are primarily modulated by orographic mechanical lifting through changes in cross-slope wind speed. However, winds directed along background horizontal moisture gradients also influence lower-tropospheric moisture variations in some regions. The buoyancy measure is also shown to explain many aspects of the spatial patterns of precipitation. Finally, we present a linear model with two horizontal dimensions that combines mountain wave dynamics with a linearized closure exploiting the relationship between precipitation and plume buoyancy. In some regions, this model skillfully captures the spatial structure and intensity of rainfall; it underestimates rainfall in regions where time-mean ascent in large-scale convergence zones shapes lower-tropospheric humidity. Overall, these results provide new understanding of fundamental processes controlling subseasonal and spatial variations in tropical orographic precipitation. [ABSTRACT FROM AUTHOR]

A generalized methodology to deploy different types of vertical coordinate system in arbitrarily defined time‐invariant local areas of quasi‐Eulerian numerical ocean models is presented. After detailing its characteristics, we show how the general localization method can be used to improve the representation of the Nordic Seas overflows in the UK Met Office NEMO‐based eddy‐permitting global ocean configuration. Three z*‐levels with partial steps configurations localizing different types of hybrid geopotential/terrain‐following vertical coordinates in the proximity of the Greenland‐Scotland ridge are implemented and compared against a control configuration. Experiments include a series of idealized and realistic numerical simulations where the skill of the models in computing pressure forces, reducing spurious diapycnal mixing and reproducing observed properties of the Nordic Seas overflows are assessed. Numerical results prove that the localization approach proposed here can be successfully used to embed terrain‐following levels in a global geopotential levels‐based configuration, provided that the localized vertical coordinate chosen is flexible enough to allow a smooth transition between the two. In addition, our experiments show that deploying localized terrain‐following levels via the multi‐envelope method allows the crucial reduction of spurious cross‐isopycnal mixing when modeling bottom intensified buoyancy driven currents, significantly improving the realism of the Nordic Seas overflows simulations in comparison to the other configurations. Important hydrographic biases are found to similarly affect all the realistic experiments and a discussion on how their interaction with the type of localized vertical coordinate affects the realism of the simulated overflows is provided. Plain Language Summary: Numerical ocean models are arguably one of the most advanced tools the scientific community can use to study the dynamics of the world's oceans. However, the ability of an ocean model to realistically simulate ocean currents depends on the numerical techniques it employs, such as the type of vertical coordinate system. Ocean models typically implement a single type of vertical coordinate throughout the entire model domain, which is often unable to accurately represent the vast variety of physical processes driving the oceans. In this study, we propose a new method that allows different types of vertical coordinates in selected regions of the same model domain. Our method targets a particular class of ocean models (known as quasi‐Eulerian), improving the way they represent the important influence the sea floor exerts on ocean currents. After introducing our novel approach, we present the results of a series of numerical experiments where we test its skill for improving the representation of the Nordic Seas overflows, an important type of ocean current located at depth in the proximity of the Greenland‐Scotland ridge. Key Points: A general methodology to embed distinct types of vertical coordinates in local time‐invariant targeted areas of quasi‐Eulerian ocean modelsThree different hybrid geopotential/terrain‐following coordinates are localized in the Nordic overflows region of a z*‐levels global modelUsing local multi‐envelope terrain‐following levels reduces diapycnal mixing improving the realism of the simulated Nordic overflows [ABSTRACT FROM AUTHOR]

Most of the ocean's kinetic energy is contained within the mesoscale eddy field. Models that do not resolve these eddies tend to parameterize their impacts such that the parameterized transport of buoyancy and tracers reduces the large‐scale available potential energy and spreads tracers. However, the parameterizations used in the ocean components of current generation Earth System Models rely on an assumption of a flat ocean floor even though observations and high‐resolution modeling show that eddy transport is sensitive to the potential vorticity gradients associated with a sloping seafloor. We show that buoyancy transport coefficient diagnosed from idealized eddy‐resolving simulations is indeed reduced over both prograde and retrograde bottom slopes (topographic wave propagation along or against the mean flow, respectively) and that the reduction can be skilfully captured by a mixing length parameterization by introducing the topographic Rhines scale as a length scale. This modified "GM" parameterization enhances the strength of thermal wind currents over the slopes in coarse‐resolution, non‐eddying, simulations. We find that in realistic global coarse‐resolution simulations the impact of topography is most pronounced at high latitudes, enhancing the mean flow strength and reducing temperature and salinity biases. Reducing the buoyancy transport coefficient further with a mean‐flow dependent eddy efficiency factor, has notable effects also at lower latitudes and leads to reduction of global mean biases. Plain Language Summary: Due to their high computational costs, global climate models are usually run at coarse spatial resolution, which does not allow them to resolve the ocean weather—mesoscale eddies—which are an important part of the ocean energy cycle and contribute to mixing of tracers such as heat and carbon. Eddies are instead parameterized in an idealized manner which relates the eddy‐driven transport to the strength of the vertical and horizontal density gradients in the ocean. Such parameterizations do not take into account impacts of large‐scale bottom bathymetry which have been shown to weaken the eddy driven transport. Here we use high‐resolution eddy‐resolving simulations to improve existing parameterizations so that they become sensitive to the bottom slope. We show that such a parameterization qualitatively captures the transport reduction seen in idealized high‐resolution simulations and can also reduce errors in realistic global simulations. Key Points: Eddy buoyancy diffusivity reduction over bottom slopes can be parameterized using the Eady growth rate and topographic Rhines scaleRealistic reduction in buoyancy diffusivity in a coarse‐resolution model strengthens baroclinic boundary currentsA topographically‐aware eddy efficiency factor improves the parameterization and further reduces biases in global simulations [ABSTRACT FROM AUTHOR]

This paper reports the experimental results of the vortex-induced vibration (VIV) of a lazy-wave flexible riser filled with different fluid media, including the water and helium as typical liquid and light gas examples. The lazy-wave configuration was produced by mounting a buoyancy module of approximately triple the riser diameter on the one-third of the riser length measured from the riser base. The VIV tests were carried out in the depth-averaged reduced velocity ( U ¯ r ) range of 9.32–23.19 using the non-intrusive optical measurement with a couple of high-speed cameras. The experimental results indicate that not only the excited mode of in-plane response but also the response amplitude is significantly adjusted when the internal fluid changes, while the excited mode of the out-of-plane response has no obvious modification. Both the water- and helium-filled risers experience the space-varying dominant frequency. However, the helium-filled riser segment possessing a higher dominant frequency is significantly shortened as compared to the water-filled one. When the internal fluid shifts from water to helium, the in-plane mode transition from the first to second becomes incomplete, and the mode transition becomes smoother as U ¯ r grows. It is found that the starting position of the mode transition is related to the dominant mode as well as the response direction. Then, the influenced length of the riser response from the buoyancy module and the affecting length of the riser on the buoyancy module response are quantified in terms of the spatial distribution of the dominant frequency in comparison with the natural frequencies. The in-plane response of the helium-filled riser is more vulnerable to the oscillation of the buoyancy module, and hence, the coupling between the in-plane and out-of-plane responses is weaker than the water-filled riser. When the impact of buoyancy module on the riser response is enhanced, the reverse effect is weakened. [ABSTRACT FROM AUTHOR]

In this study, an in-depth examination of the aerodynamic parameters involving forced and mixed convection around a heated square cylinder is presented. The ranges of Prandtl number (Pr), Richardson number (Ri), and flow orientation (α) are kept as 0.71 ≤ Pr ≤ 1000, 0 ≤ Ri ≤ 1.6, 0° ≤ α ≤ 90°, while the Reynolds number (Re) and the cylinder orientation (ϕ) are kept fixed as Re = 100 and ϕ = 0°, respectively. The flow is considered as two-dimensional (2D), steady, laminar, incompressible, and viscous. The buoyancy effects are taken into account through the Boussinesq approximation. At lower Pr, the flow shifts from unsteady to steady with increasing Ri. This transition persists at higher Ri with increasing Prandtl values. The flow remains consistently unsteady at α = 90°. Isotherm crowding intensifies with higher Pr and/or Ri across all flow inclinations. Across the complete spectrum of flow angles, it is noted that the mean lift coefficient rises as the Richardson number increases. Additionally, the mean drag coefficient reaches its peak at Ri = 1.6 when Pr = 0.71. The findings reveal that the Strouhal number (St) rises as the Richardson number (Ri) increases, and it decreases as the Prandtl number (Pr) increases. The mean Nusselt number ( Nu ¯) demonstrates an upward trend as the Prandtl number increases, with Ri held constant. It is also observed that Nu ¯ is more sensitive to the Prandtl number than the Richardson number and is maximum at Pr = 1000 for the selected range of flow orientations. [ABSTRACT FROM AUTHOR]

During mining activities, deep-sea mining vehicles (DSMVs) are highly susceptible to causing massive disturbance to the seafloor sediment, resulting in the formation of plumes due to underlying turbulence and currents. To gain a better understanding of the dispersion mechanism of sediment plumes, both experimental and numerical methods were employed. The numerical model was primarily used to characterize the solidity and liquidity of the sediment plume through volume of fluid and discrete phase model methods, respectively. The experimental data were validated against the numerical results. The plume distribution was studied in physical experiments for three different DSMV parameters. The study findings indicate that the discharge of the plume in the near field occurs in three stages due to a combination of plume release inertial forces, negative buoyancy in the water column, and wall restoring forces. Additionally, the increase in the travel velocity of the DSMV reduces the propagation of the plume in the direction of discharge and instead increases its lateral spread across the bottom surface. As the size of the DSMV decreases in three dimensions, changes in the vertical vortex structure become dominant in the plume distribution. This leads to a reduction in the length of the plume head and a faster sinking of the plume. When the wake Froude number Frw is between 0.7 and 6.8, representing the wake turbulence effect of DSMV on plume discharge, the diffusion width of the plume on the bottom surface is linearly related to Frw. [ABSTRACT FROM AUTHOR]

This study investigated the weakly nonlinear propagation of pressure waves in compressible, flowing water with spherical microbubbles, considering various forces. Previous theoretical studies on nonlinear pressure waves in bubbly flows did not consider the forces acting on the bubbles, although the validity of ignoring these forces has not been demonstrated. We focused on every possible force such as drag, gravity, buoyancy, and Bjerknes (acoustic radiation) forces acting on bubbles and studied their effects on pressure waves in a one-dimensional setting. Using a singular perturbation method, the Korteweg–de Vries–Burgers equation describing wave propagation was derived. The following results were obtained: (i) Bjerknes force on the bubbles enhanced the nonlinearity, dissipation, and dispersion of the waves; (ii) Drag, gravity, and buoyancy forces acting on the bubbles increased wave dissipation; (iii) Thermal conduction had the most substantial dissipation effect, followed by acoustic radiation, drag, buoyancy, and gravity. We confirmed that the dissipation due to forces on gas bubbles was quantitatively minor. [ABSTRACT FROM AUTHOR]

In a smoothly bounded two‐dimensional domain Ω$\Omega$ and for a given nondecreasing positive unbounded ℓ∈C0([0,∞))$\ell \in C^0([0,\infty))$, for each K>0$K>0$ and η>0$\eta >0$ the inequality ∫Ωφlnφ⩽η∫Ω|∇φ|2φ2+C(K,η)$$\begin{eqnarray*} \hspace*{140pt} \int _\Omega \varphi \ln \varphi \leqslant \eta \int _\Omega \frac{|\nabla \varphi|^2}{\varphi ^2} + C(K,\eta) \end{eqnarray*}$$is shown to hold for any positive φ∈C1(Ω¯)$\varphi \in C^1(\overline{\Omega })$ fulfilling ∫Ωφℓ(φ)⩽K.$$\begin{eqnarray*} \hspace*{100pt}\int _\Omega \varphi \ell (\varphi) \leqslant K. \end{eqnarray*}$$This is thereafter applied to nonglobal solutions of the Keller–Segel system coupled to the incompressible Navier–Stokes equations through transport and buoyancy, and it is seen that in any such blow‐up event the corresponding population density cannot remain uniformly integrable over Ω$\Omega$ near its explosion time. [ABSTRACT FROM AUTHOR]

We develop a probabilistic approach to map parametric uncertainty to output state uncertainty in first‐order hyperbolic conservation laws. We analyze this problem for nonlinear immiscible two‐phase transport in heterogeneous porous media in the presence of a stochastic velocity field. The uncertainty in the velocity field can arise from incomplete descriptions of either porosity field, injection flux, or both. This uncertainty leads to spatiotemporal uncertainty in the saturation field. Given information about spatial/temporal statistics of spatially correlated heterogeneity, we leverage the method of distributions to derive deterministic equations that govern the evolution of pointwise cumulative distribution functions (CDFs) of saturation for a vertical reservoir, while handling the manipulation of multiple shocks arising due to buoyancy forces. Unlike the Buckley‐Leverett equation, the equation describing the fine‐grained CDF is linear in space and time. Ensemble averaging of the fine‐grained CDF results in the CDF of saturation. Thus, we give routes to circumventing the computational cost of Monte Carlo simulations (MCS), while obtaining a pointwise description of the saturation field. We conduct a set of numerical experiments for one‐dimensional transport, and compare the obtained saturation CDFs, against those obtained using MCS as our reference solution, and the statistical moment equation method. This comparison demonstrates that the CDF equations remain accurate over a wide range of statistical properties, that is, standard deviation and correlation length of the underlying random fields, whereas the corresponding low‐order statistical moment equations significantly deviate from the MCS results, except for very small values of standard deviation and correlation length. Key Points: Our cumulative distribution function method provides pointwise probabilistic descriptions of two‐phase transport, handling multiple shocks arising due to buoyancy forcesOur results match Monte Carlo (MC) simulations and statistical moment equations for a wide range of statistical properties of the random inputsThe numerical comparisons confirm the robustness and efficiency of our method over MC simulations and statistical moment equations [ABSTRACT FROM AUTHOR]

Rotational buoyancy assumes a substantial role in a multitude of natural and engineering systems, with particular emphasis on astrophysical and geophysical scenarios. The primary objective of this study is to delve into the intricate dynamics of a rotational flow subjected to forces from rotational buoyancy, magnetic field, Hall effects, and infrared radiation in a Casson fluid medium adjacent to a thermal plate. The LT technique is harnessed to yield the closed‐form solutions for the dimensionless governing flow system. Through graphical analyzes, the physical implications of key contextual parameters are elucidated. Our findings demonstrate that Hall currents and rotational buoyancy forces jointly act to restrict primary fluid motion while amplifying secondary motion. An upswing in the Casson parameter leads to a marked reduction in the magnitude of the velocity components. Furthermore, intensified infrared radiation results in a more flattened thermal distribution. The primary directional shear stress attenuates, while an inverse bias is observed for the shear stress along the secondary direction, particularly with higher values of the Hall and rotation parameters. The insights gained from this study have practical implications for the design and operation of various systems involving rotational components, such as rotary machinery, automotive systems, and industrial automation, and contribute to weather forecasting and climate modelling. [ABSTRACT FROM AUTHOR]

The Southern Ocean hosts a winter deep mixing band (DMB) near the Antarctic Circumpolar Current's (ACC) northern boundary, playing a pivotal role in Subantarctic Mode Water formation. Here, we investigate what controls the presence and geographical extent of the DMB. Using observational data, we construct seasonal climatologies of surface buoyancy fluxes, Ekman buoyancy transport, and upper stratification. The strength of the upper-ocean stratification is determined using the columnar buoyancy index, defined as the buoyancy input necessary to produce a 250 m deep mixed layer. It is found that the DMB lies precisely where the autumn–winter buoyancy loss exceeds the columnar buoyancy found in late summer. The buoyancy loss decreases towards the south, while in the north the stratification is too strong to produce deep mixed layers. Although this threshold is also crossed in the Agulhas Current and East Australian Current regions, advection of buoyancy is able to stabilise the stratification. The Ekman buoyancy transport has a secondary impact on the DMB extent due to the compensating effects of temperature and salinity transports on buoyancy. Changes in surface temperature drive spatial variations in the thermal expansion coefficient (TEC). These TEC variations are necessary to explain the limited meridional extent of the DMB. We demonstrate this by comparing buoyancy budgets derived using varying TEC values with those derived using a constant TEC value. Reduced TEC in colder waters leads to decreased winter buoyancy loss south of the DMB, yet substantial heat loss persists. Lower TEC values also weaken the effect of temperature stratification, partially compensating for the effect of buoyancy loss damping. TEC modulation impacts both the DMB characteristics and its meridional extent. [ABSTRACT FROM AUTHOR]

We explore historical variability in the volume of Labrador Sea Water (LSW) using ECCO, an ocean state estimate configuration of the Massachusetts Institute of Technology general circulation model (MITgcm). The model's adjoint, a linearization of the MITgcm, is set up to output the lagged sensitivity of the water mass volume to surface boundary conditions. This allows us to reconstruct the evolution of LSW volume over recent decades using historical surface wind stress, heat, and freshwater fluxes. Each of these boundary conditions contributes significantly to the LSW variability that we recover, but these impacts are associated with different geographical fingerprints and arise over a range of time lags. We show that the volume of LSW accumulated in the Labrador Sea exhibits a delayed response to surface wind stress and buoyancy forcing outside the convective interior of the Labrador Sea at important locations in the North Atlantic Ocean. In particular, patterns of wind and surface density anomalies can act as a "traffic controller" and regulate the North Atlantic Current's (NAC's) transport of warm and saline subtropical water masses that are precursors for the formation of LSW. This propensity for a delayed response of LSW to remote forcing allows us to predict a limited yet substantial and significant fraction of LSW variability at least 1 year into the future. Our analysis also enables us to attribute LSW variability to different boundary conditions and to gain insight into the major mechanisms that contribute to volume anomalies in this deep water mass. We point out the important role of key processes that promote the formation of LSW in both the Irminger and Labrador seas: buoyancy loss and preconditioning along the NAC pathway and in the Iceland Basin, the Irminger Sea, and the Nordic Seas. [ABSTRACT FROM AUTHOR]

It is beneficial for disaster prevention and mitigation to use a numerical model to evaluate landslide stability. The Sifangbei landslide, located in the Three Gorges Reservoir Area (TGRA), is sliding slowly under the action of reservoir water. Due to the lack of early technology and funds, the depiction of the longitudinal profile and stability analysis of the landslide are very limited. In this study, the longitudinal profile of the main sliding direction was corrected from the original version of the ground model using field investigation, drilling, in situ monitoring, and geophysical observation. Then, through the establishment of numerical models, the landslide model based on the original profile is used as a reference to re-study its deformation characteristics and stability analysis. The results are as follows: The displacement response of the new model is closer to the real deformation record of the landslide. The deformation of the landslide body in the rear section and front edge is significant, even during periods of low rainfall in the reservoir storage season. According to the hydraulic mechanism, the stability changes of the two models under the influence of RWL show that there is a stronger buoyancy force of the soil mass in the front resisting section after the profile of the model is modified. The above conclusions indicate that the Sifangbei landslide is not a typical seepage-driven landslide, and its prevention and control should be updated in time. This study also provides a case for the same type of landslide and the relationship between the landslide deformation and the sliding surface shape. [ABSTRACT FROM AUTHOR]

Every year several ships sink in the ocean because of storms and other reasons. The ship design system must be integrated inter-communicating with all components of the system. The design of architecture, civil engineering, electronic sub-systems, mechanical engineering, metallurgical engineering, and more especially the telecommunications must be formulated in one unified system. This paper tries to classify the ship-design and faults of the systems and sub-systems and how to be updated for safety. Moreover, it focuses on various architectural and engineering faults in ship design during manufacturing. The ship design is required to be flexible to accommodate new updates after factory-made. Naval architecture relies on mechanics, material strength, and structure design. The mission of a ship is determined by its deployment, cargo, cruising radius, operating, maximum speed, mobilization, passengers, and safety. A strong computerized telecommunication system is essential for all ships, integrated architecture with all devices electronic sub-systems. All the devices used in ship design must be consistent and in conformity with applicable disciplines of engineering and telecommunications to form unified and integrated system. The strong system operated via satellite is required to be installed for safety. The Geographical Information System (GIS) and Global Climatology system help ports and ship navigation of the locations, hazards, high winds, and storms. As a final point, the results are reported as the recommendations. [ABSTRACT FROM AUTHOR]

Abstract The concept of language teacher immunity is a relatively new notion that has been introduced in the field of language teacher psychology. It is imperative that teachers have their inherent immunity strengthened since they have never been intrinsically protected against fluctuations that are unanticipated and beyond their control. In order to achieve this goal, the present research used a quantitative approach in order to investigate the possible effects of teacher immunity on their psychological well-being, buoyancy, and engagement. This study was conducted by sending out three questionnaires to a total of 384 primary language teachers. On the basis of the findings, it was concluded that teacher immunity has the potential to serve as a significant predictor of English as a foreign language (EFL) teachers’ psychological well-being, buoyancy, and engagement. The research’s conclusions may have substantial implications for education in terms of advancing psychological well-being, buoyancy, and engagement.

Abstract In this study, a sandwich composite structure was fabricated with core syntactic foam composites (SFC) reinforced with face-sheets of combined kenaf and glass fibers. The core SFC was made from hollow glass microsphere (HGM)/epoxy resin mixture. The focus of this study is to design a suitable material for marine, automobile, and structural applications by investigating the water absorption capacity, hardness, buoyancy, and acoustic resistance level of the sandwich composite. Four sequences of face-sheet reinforcement [e.g. kenaf-kenaf(KK); glass-glass(GG); glass-kenaf(GK), and kenaf-glass(KG)] were adopted. The results show that the KK sandwich absorbed more water, with buoyancy level of 0.329% than other sequence. GK shows the highest sandwich in hardness strength with 58Hv, and 35% more than the KK, while there was no significant difference in the sound pressure level of the sandwich composite.

Bu çalışmada, eğik bir plakanın tek bir slot jet ile soğutulmasında kaldırma kuvveti ve yüzeyler arası ışınımın taşınımla ısı transferine etkileri sayısal olarak incelenmiştir. Çalışma jet Reynolds sayısının (Re_j) 100 ile 1000 değerleri arasında gerçekleştirilmiş olup Richardson sayısı (Ri) ise 0.1 ile 10 arasında değişmektedir. Yüzeyler arası ışınımla ısı transferinin genel ısı transfer performansına etkileri hedef plaka ve sınırlandırıcı yüzeylerin üç farklı yayıcılık (ε=0.05-0.5-0.95) değeri ve üç farklı eğim açısı (α=0°-5°-10°) için analiz edilmiştir. Boyutsuz hedef plaka-nozul çapı mesafesi (H/D_j) 4’e eşit olup havanın (Pr=0.71) ışınım açısından katılımcı olmadığı kabulüyle hesaplamalar gerçekleştirilmiştir. Çalışma sonucunda, yüksek Richardson sayılarında kaldırma kuvvetinin akış ve ısı transfer karakteristiklerinin üzerindeki etkisinin ihmal edilemeyecek düzeyde olduğu, yüzey yayıcılığının artışının ise genel ısı transfer performansını iyileştirdiği ve plaka eğiminin ısı transferini önemli ölçüde etkilediği belirlenmiştir.

In the recent literature, attention has been drawn to the previously uninvestigated mechanism of the occurrence of flows in a stratified fluid in a gravity field. Such flows can occur in the absence of pulse and buoyancy sources due to horizontal inhomogeneity of transfer coefficients. For the first time, this investigation provides an example of an exact analytical solution of such a problem free from assumptions of amplitude smallness. [ABSTRACT FROM AUTHOR]

The importance of studying teachers' professional well-being has increased greatly in recent years. However, researchers have not paid enough attention to how teachers' levels of immunity, buoyancy, and emotion regulation (ER) in the classroom all play a role in shaping teachers’ L2 grit and mindfulness. This research seeks to address this gap in the literature by presenting a model of the dynamic interaction of teacher immunity (TI), teacher buoyancy (TB), teacher emotion regulation (TER), L2 grit, and teacher mindfulness (TM). To gather this information, 519 English as a foreign language (EFL) teachers were given surveys measuring their levels of mindfulness in the classroom using the language teacher immunity instrument (LTII), teacher buoyancy scale (TBS), Teacher Emotion Regulation Inventory (LTERI), the L2-teacher grit scale (L2TGS), and Mindfulness in Teaching Scale (MTS). Confirmatory factor analysis (CFA) and structural equation modeling (SEM) results indicated that EFL instructors who achieved a healthy state of immunity (TI), TER, L2 grit had higher levels of L2 grit, and TM. The research winds down with implications and future directions for relevant stakeholders to improve their understanding of the relationship between TI, TB, TER, L2 grit, and TM interactions and their potential to provide favorable educational results for EFL learners.

Based on the data of long-term coastal and expeditionary observations, the structure and dynamics of transitional waters in the system of the Dnieper-Bug estuary (the DBE) before the destruction of the Kakhovka HPP are considered as the basis for the future description of changes in the hydrological regime. Average annual and seasonal maps and vertical sections of temperature and salinity are drafted. The article analyzes the main factors of formation and distribution of transitional waters such as river runoff, salinity (density) contrast and surface wind. A number of dimensional and dimensionless criteria and indicators of the transitional water dynamics within and outside the DBE are calculated and analyzed. The analysis of previous studies of river water transformation in the North-Western part of the Black Sea (NWBS) and dynamics of floating plumes in other areas of the World Ocean's coastal zone allows us to establish a 14 P.S.U. isohaline as the outer limit for transitional waters of the NWBS. According to the monitoring data of 1992-2020, the highest degree of desalination of the DBE and output of transition water from the Kinburn Strait was observed in spring, under the conditions of increasing volume of river runoff and predominant wind from the east. At the same time, the increasing repeatability of the south wind contributed to pushing the plume towards the coastal area outside the estuary. In summer, the influence of open sea waters on the DBE increased due to decreasing river runoff and increasing frequency of westerly winds. According to theoretical criteria, under low-wind conditions, the estuary produces a surface-advective plume affected by buoyancy and Coriolis force, with no effect of friction in the bottom boundary layer. The distance over which such plume spreads, even in summer, does not exceed half way from the Kinburn Strait to the Odesa Bay. The ingress thereto of transitional waters of the DBE in spring and autumn can be facilitated by accompanying wind currents. The main factor of the plume's summer dynamics includes both westerly wind and the currents it generates. The latter prevent the spread of transitional waters to the west along the coast, pushing them towards the estuary and to the south off it. This does not negate the possibility of a different plume behavior due to the increasing volume of river runoff and synoptic variability of the wind field during certain years and months.

Education for Sustainable Development (ESD) equips learners in all settings with the knowledge, skills, attributes, and visions essential for coping with the diverse challenges they will encounter in their educational endeavors. The emergence of COVID-19 influenced different aspects of human life including education. Thanks to technology, especially ICT, Virtual Education (VE) provides the opportunity to continue education in such crises. Amidst this pandemic, many students, especially university students, encountered various challenges and impediments that resulted from VE. One of the factors which can affect VE is learners’ resilience. Therefore, it is of high importance to measure university students’ Resilience in Virtual Education (RVE) to recognize the advantages and disadvantages of this type of education and support ESD. The main purpose of this study is to design and validate a comprehensive instrument for measuring university students’ RVE. Furthermore, to confirm the validity and reliability of the instrument, its nexus with a closely related construct, i.e., second language (L2) buoyancy was explored. To measure students’ RVE, a new scale (RVE Scale), comprising 33 items, was designed. It was designed based on the operational definition of academic resilience and was adapted to accommodate the requirements of VE. It measures six aspects of learners’ resilience: emotional, motivational, cognitive, metacognitive, persistence, and sociability. To measure L2 buoyancy, a relevant scale designed by Jahedizadeh et al. (2019) was utilized. It consists of 27 items with four factors; the factors include sustainability, regularity adaptation, positive personal eligibility, and positive acceptance of academic life. A total of 412 university students participated in the present research. The results obtained via Confirmatory Factor Analysis (CFA) substantiated the validity of the newly designed scale and all the factors and items. The results attested to the criterion-related validity of the scale.

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.