Buoyant Layer Research Articles

Development and Evaluation of Floating Pulsatile Drug Delivery System Using Meloxicam

Objective: The objective of this research work was to develop and evaluate the floating– pulsatile drug delivery system (FPDDS) of meloxicam intended for Chrono pharmacotherapy of rheumatoid arthritis. Methods: The system consisting of drug containing core, coated with hydrophilic erodible polymer, which is responsible for a lag phase for pulsatile release, top cover buoyant layer was prepared with HPMC K4M and sodium bicarbonate, provides buoyancy to increase retention of the oral dosage form in the stomach. Meloxicam is a COX-2 inhibitor used to treat joint diseases such as osteoarthritis and rheumatoid arthritis. For rheumatoid arthritis Chrono pharmacotherapy has been recommended to ensure that the highest blood levels of the drug coincide with peak pain and stiffness. Result and discussion: The prepared tablets were characterized and found to exhibit satisfactory physico-chemical characteristics. Hence, the main objective of present work is to formulate FPDDS of meloxicam in order to achieve drug release after pre-determined lag phase. Developed formulations were evaluated for in vitro drug release studies, water uptake and erosion studies, floating behaviour and in vivo radiology studies. Results showed that a certain lag time before drug release which was due to the erosion of the hydrophilic erodible polymer. The lag time clearly depends on the type and amount of hydrophilic polymer which was applied on the inner cores. Floating time and floating lag time was controlled by quantity and composition of buoyant layer. In vivo radiology studies point out the capability of the system of longer residence time of the tablets in the gastric region and releasing the drug after a programmed lag time. Conclusion: The optimized formulation of the developed system provided a lag phase while showing the gastroretension followed by pulsatile drug release that would be beneficial for chronotherapy of rheumatoid arthritis and osteoarthritis.

PARENT CHILD RELATIONSHIP OF SECONDARY SCHOOL GIRL CHILDREN IN THE CONTEXT OF LOCALITY AND DIFFERENT SCHOOL BACKGROUND

Objective: The objective of this research work was to develop and evaluate the floating– pulsatile drug delivery system (FPDDS) of meloxicam intended for Chrono pharmacotherapy of rheumatoid arthritis. Methods: The system consisting of drug containing core, coated with hydrophilic erodible polymer, which is responsible for a lag phase for pulsatile release, top cover buoyant layer was prepared with HPMC K4M and sodium bicarbonate, provides buoyancy to increase retention of the oral dosage form in the stomach. Meloxicam is a COX-2 inhibitor used to treat joint diseases such as osteoarthritis and rheumatoid arthritis. For rheumatoid arthritis Chrono pharmacotherapy has been recommended to ensure that the highest blood levels of the drug coincide with peak pain and stiffness. Result and discussion: The prepared tablets were characterized and found to exhibit satisfactory physico-chemical characteristics. Hence, the main objective of present work is to formulate FPDDS of meloxicam in order to achieve drug release after pre-determined lag phase. Developed formulations were evaluated for in vitro drug release studies, water uptake and erosion studies, floating behaviour and in vivo radiology studies. Results showed that a certain lag time before drug release which was due to the erosion of the hydrophilic erodible polymer. The lag time clearly depends on the type and amount of hydrophilic polymer which was applied on the inner cores. Floating time and floating lag time was controlled by quantity and composition of buoyant layer. In vivo radiology studies point out the capability of the system of longer residence time of the tablets in the gastric region and releasing the drug after a programmed lag time. Conclusion: The optimized formulation of the developed system provided a lag phase while showing the gastroretension followed by pulsatile drug release that would be beneficial for chronotherapy of rheumatoid arthritis and osteoarthritis.

Experimental investigation of large-scale vortices in a freely spreading gravity current

A series of laboratory experiments are presented to compare the dynamics of constant-source buoyant gravity currents propagating into laterally confined (channelized) and unconfined (spreading) environments. The plan-form structure of the spreading current and the vertical density and velocity structures on the interface are quantified using the optical thickness method and a combined particle image velocimetry and planar laser-induced fluorescence method, respectively. With lateral boundaries, the buoyant current thickness is approximately constant and Kelvin-Helmholtz instabilities are generated within the shear layer. The buoyant current structure is significantly different in the spreading case. As the current spreads laterally, nonlinear large-scale vortex structures are observed at the interface, which maintain a coherent shape as they propagate away from the source. These structures are continuously generated near the river mouth, have amplitudes close to the buoyant layer thickness, and propagate offshore at speeds approximately equal to the internal wave speed. The observed depth and propagation speed of the instabilities match well with the fastest growing mode predicted by linear stability analysis, but with a shorter wavelength. The spreading flows have much higher vorticity, which is aggregated within the large-scale structures. Secondary instabilities are generated on the leading edge of the braids between the large-scale vortex structures and ultimately break and mix on the lee side of the structures. Analysis of the vortex dynamics shows that lateral stretching intensifies the vorticity in the spreading currents, contributing to higher vorticity within the large-scale structures in the buoyant plume. The large-scale instabilities and vortex structures observed in the present study provide new insights into the origin of internal frontal structures frequently observed in coastal river plumes.

Thermal instability in a time-dependent base state due to sudden heating

When a large body of fluid is heated from below at a horizontal surface, the heat diffuses into the fluid, giving rise to a gravitationally unstable layer adjacent to the boundary. A consideration of the instantaneous Rayleigh number using the thickness of this buoyant layer as a length scale would lead one to expect that the heated fluid is initially stable, and only becomes unstable after a finite time. This transition would also apply to other situations, such as heating a large body of fluid from the side, where a buoyant upward flow develops near the boundary. In such cases, when the evolving thermal boundary layer first becomes unstable, the time scale for the growth of the instabilities may be comparable to the time scale of the evolution of the background temperature profile, and so analytical approximations such as the quasi-static approximation, where the time evolution of the background state is ignored, are not strictly appropriate. We develop a numerical scheme where we find the optimal growth of linear perturbations to the background flow over a given time interval. Part of this problem is to determine an appropriate measure of the amplitude to the disturbances, as inappropriate choices can lead to apparent growth of disturbances over finite time intervals even when the fluid is stable. By considering the Rayleigh–Bénard problem, we show that these problems can be avoided by choosing a measure of the amplitude that uses both the velocity and temperature perturbations, and which minimizes the maximum growth. We apply our analysis to the problems of heating a semi-infinite body of fluid from horizontal and vertical boundaries. We will show that for heating from a vertical boundary there are large- and small-Prandtl-number modes. For some Prandtl numbers, both modes may play a role in the growth of instabilities. In some cases there is transition during the evolution of the most unstable instabilities in fluids such as water, where initially the instabilities are large-Prandtl-number modes and then morph into small-Prandtl-number modes part of the way through their evolution.

The discharge plume parameter and its implications for an emptying–filling box

The natural ventilation flow driven by an internal buoyant plume in a box involving an upper opening (vent) located at the ceiling (for the outflow) and a large lower opening at the floor (for the inflow) is examined theoretically in a general non-Boussinesq case. Analytical solutions of this emptying–filling box problem allow the characteristics of the flow at the vent to be determined. From these characteristics, a non-dimensional parameter $\unicode[STIX]{x1D6E4}_{d}$ (called the discharge plume parameter) is expressed. This parameter characterizes the initial balance of volume, buoyancy and momentum fluxes in the plume-like flow that forms above the vent. We then note that the value of $\unicode[STIX]{x1D6E4}_{d}$ allows the buoyant fluid layer depth in the box to be estimated, which is a new and interesting result for natural ventilation problems. Following previous experimental results, the decrease of the vent discharge coefficient $C_{d}$ when $\unicode[STIX]{x1D6E4}_{d}$ increases is discussed and a theoretical model based on plume necking is proposed. The emptying–filling box model is then extended for a variable $C_{d}$ (depending on $\unicode[STIX]{x1D6E4}_{d}$). Even though the discharge coefficient may be markedly reduced at high values of $\unicode[STIX]{x1D6E4}_{d}$, our results show that this only affects transients and the steady state of an emptying–filling box for relatively thin buoyant fluid layers.

Hydrogen Council launched in Davos as 13 major companies join to promote hydrogen

A series of experiments were carried out in a model-scale tunnel [72 m (length) × 1.5 m (width) × 1.3 m (height)] to investigate the buoyant flow stratification behaviors in a tunnel fire with complexity of combination of longitudinal ventilation and ceiling extraction, which had not been studied before. The horizontal traveling velocity and vertical temperature profile were measured. The buoyant flow stratification conditions were visualized by a laser-sheet, as well as determined objectively by the vertical temperature profile measured. Buoyancy and inertial force are the two important factors influencing the buoyancy stratification. The interaction between them can be expressed by the Froude number or Richardson number. It was found that the buoyant stratification pattern was divided into three regimes. At regime I (Ri > 2.0 or Fr < 0.66), the buoyant stratification was stable and with a clear interface between the upper buoyant flow layer and the lower air layer. At regime II (1.4 < Ri < 2.0 or 0.66 < Fr < 0.8), the buoyant stratification was basically stable, but some vortexes existed at the interface. At regime III (Ri < 1.4 or Fr > 0.8), a strong mixing existed between the upper buoyant flow and the lower air flow, that the buoyant flow stratification became unstable.

Unsteady CFD Simulation in a Naturally Ventilated Room with a Localized Heat Source

This study examines the temperature distribution and the flow field in a naturally ventilated room with a localized floor heat source. The room has an orthogonal form with a low and a high opening placed in opposite walls. The temperature of outdoor air is cooler than the initial indoor air temperature forming buoyancy-driven natural ventilation (with Uwind≈0). The problem is explored with computational simulation using a CFD software. A model validation is presented with experimental and computational results of previous investigation10,11 on natural ventilation including buoyancy forces. The 3D unsteady Reynolds Averaged Navier Stokes (RANS) equations are solved in conjunction with the energy equation and the turbulence RNG k-ɛmodel. The unsteady flow of natural ventilation with buoyancy forces is analyzed andthe vertical variation of temperature with respect to timeis investigated. A thermal stratification is formed which is justified by the respective indoor air movement. The upper buoyant layer is warmer than the bottom one, while the indoor air temperature of both layers increases with time. A thermal comfort exploration accompanies the outcoming results and provides useful information for similar problems. Finally, a number of conclusions are derived about the simulation process, the function of natural ventilation and the thermal comfort of the space in corresponding cases.

Spatial diversity of ambient noise in the new Arctic

The Arctic Ocean is undergoing dramatic changes, the most apparent being the rapidly reducing extent and thickness of the summer ice cover. As has been well established over prior decades, the environmental acoustics of the ice-covered Arctic is dominated by two major effects: the highly inhomogeneous ice cover, and the monotonically upward refracting sound speed profile, the combination of which forces all sound paths to be exposed to strong scattering loss and the associated loss of coherence. In some portions of the Arctic Ocean, however, inflow of warm Pacific water has created the so-called “Beaufort Lens,” a neutrally buoyant high sound velocity layer at 70-80 meter depth, which has dramatically altered the acoustic environment, creating a strong acoustic duct between approximately 100 and 300 m depth. This duct has the potential of trapping sound out to significant ranges (80-100 km) without interacting with the ice cover, resulting in much higher coherence and signal preservation. Acoustic noise measurement results collected with a vertically suspended array during ICEX 2016 illustrate the spatial and temporal noise properties in the presence of this acoustic duct at different depths. Comparisons of the ICEX 2016 data are also made with modeled Arctic noise data. [Work supported by ONR and DARPA.]

Environmentally adaptive autonomy for acoustic communication and navigation in the new Arctic

The particular sensitivity of the Arctic to climate change is well established. and the significance to undersea operations can be dramatic. As part of the recent ICEX16 US Navy Exercise in the Beaufort Sea, MIT deployed an autonomous underwater vehicle with a towed hydrophone array below the ice cover for assessing the climate induced changes to the undersea ambient noise environment. The safe underwater operation depended on navigation updates from the submarine tracking range being communicated to the vehicle for fusion with the onboard inertial navigation. However, the changes in the environment severely deteriorated the tracking performance compared to previous deployments. The reason was clearly associated with a previously observed neutrally buoyant layer of warm Pacific water persistently spreading throughout the Beaufort Sea, which severely alters the acoustic environment with dramatic effects for both long and short range acoustic sensing, communication and navigation. This paper describes the effects observed and discusses how robust acoustic connectivity in this environment makes it paramount that the manned or unmanned undersea platforms are capable of adapting to the environment for sensing, communication, and navigation. [Work supported by the Office of Naval Research.]

Tomography reveals buoyant asthenosphere accumulating beneath the Juan de Fuca plate.

The boundary between Earth's strong lithospheric plates and the underlying mantle asthenosphere corresponds to an abrupt seismic velocity decrease and electrical conductivity increase with depth, perhaps indicating a thin, weak layer that may strongly influence plate motion dynamics. The behavior of such a layer at subduction zones remains unexplored. We present a tomographic model, derived from on- and offshore seismic experiments, that reveals a strong low-velocity feature beneath the subducting Juan de Fuca slab along the entire Cascadia subduction zone. Through simple geodynamic arguments, we propose that this low-velocity feature is the accumulation of material from a thin, weak, buoyant layer present beneath the entire oceanic lithosphere. The presence of this feature could have major implications for our understanding of the asthenosphere and subduction zone dynamics.

Characterization of buoyant flow stratification behaviors by Richardson (Froude) number in a tunnel fire with complex combination of longitudinal ventilation and ceiling extraction

A series of experiments were carried out in a model-scale tunnel [72m (length)×1.5m (width)×1.3m (height)] to investigate the buoyant flow stratification behaviors in a tunnel fire with complexity of combination of longitudinal ventilation and ceiling extraction, which had not been studied before. The horizontal traveling velocity and vertical temperature profile were measured. The buoyant flow stratification conditions were visualized by a laser-sheet, as well as determined objectively by the vertical temperature profile measured. Buoyancy and inertial force are the two important factors influencing the buoyancy stratification. The interaction between them can be expressed by the Froude number or Richardson number. It was found that the buoyant stratification pattern was divided into three regimes. At regime I (Ri>2.0 or Fr<0.66), the buoyant stratification was stable and with a clear interface between the upper buoyant flow layer and the lower air layer. At regime II (1.4<Ri<2.0 or 0.66<Fr<0.8), the buoyant stratification was basically stable, but some vortexes existed at the interface. At regime III (Ri<1.4 or Fr>0.8), a strong mixing existed between the upper buoyant flow and the lower air flow, that the buoyant flow stratification became unstable.

Effects of rotation on turbulent buoyant plumes in stratified environments

AbstractWe numerically investigate the effects of rotation on the turbulent dynamics of thermally driven buoyant plumes in stratified environments at the large Rossby numbers characteristic of deep oceanic releases. When compared to nonrotating environments, rotating plumes are distinguished by a significant decrease in vertical buoyancy and momentum fluxes leading to lower and thicker neutrally buoyant intrusion layers. The primary dynamic effect of background rotation is the concentration of entraining fluid into a strong cyclonic flow at the base of the plume resulting in cyclogeostrophic balance in the radial momentum equation. The structure of this cyclogeostrophic balance moving upward from the well head is associated with a net adverse vertical pressure gradient producing an inverted hydrostatic balance in the mean vertical momentum budgets. The present simulations reveal that the primary response to the adverse pressure gradient is an off‐axis deflection of the plume that evolves into a robust, organized anticyclonic radial precession about the buoyancy source. The off‐axis evolution is responsible for the weaker inertial overshoots, the increased thickness of lateral intrusion layers, and the overall decrease in the vertical extent of rotating plumes at intermediate Rossby numbers compared to the nonrotating case. For inlet buoyancy forcings and environmental Rossby numbers consistent with those expected in deepwater blowout plumes, the speed of the organized precession is found to be as large as typical oceanic cross‐flow speeds.

A Simple Model of the Ice Shelf–Ocean Boundary Layer and Current

AbstractOcean-forced basal melting has been implicated in the widespread thinning of Antarctic ice shelves, but an understanding of what determines melt rates is hampered by limited knowledge of the buoyancy- and frictionally controlled flows along the ice shelf base that regulate heat transfer from ocean to ice. In an attempt to address this deficiency, a simple model of a buoyant boundary flow, considering only the spatial dimension perpendicular to the boundary, is presented. Results indicate that two possible flow regimes exist: a weakly stratified, geostrophic cross-slope current with upslope flow within a buoyant Ekman layer or a strongly stratified, upslope current with a weak cross-slope flow. The latter regime, which is analogous to the steady solution for a katabatic wind, is most appropriate when the ice–ocean interface is steep. For the gentle slopes typical of Antarctic ice shelves, the buoyant Ekman regime, which has similarities with the case of an unstratified density current on a slope, provides some useful insight. When combined with a background flow, a range of possible near-ice current profiles emerge as a result of arrest or enhancement of the upslope Ekman transport. A simple expression for the upslope transport can be formed that is analogous to that for the wind-forced surface Ekman layer, with curvature of the ice shelf base replacing the wind stress curl in driving exchange between the Ekman layer and the geostrophic current below.

Empirical correlation derived by CFD simulation on heat source location and ventilation flow rate in a fire room

A series of numerical investigations of a fire induced airflow in a compartment are carried out using the Fluent 6.3CFD code, in order to examine the effect of the source location on the thermal flow field and the mass flow rate at the exit doorway. The Fire is modeled by a volumetric heat source and the induced transport flow phenomena is considered as a buoyancy-induced turbulent flow so Boussinesq approximations are applied. Resolution of the governing equations comprises the Reynolds averaged Navier-Stokes (RANS) equations using the k-ε turbulence model combined with an enhanced wall treatment.The research results show that the height position of the heat source has a significant impact on the temperature field and the stratification interface of the buoyant layer, comparing to the transversal or the longitudinal position. For the highest positions tested, the fire room becomes more stratified and essentially divided into two layers: an upper layer corresponding to the hot exhaust gases and a lower layer for the fresh air entrance. The second part of this paper was devoted to the establishment of a mathematical correlation linking firstly, the ventilation mass flow rate at the doorway exit, as a critical parameter in fire induced flow studies, and the three-dimensional coordinates of the fire source location within the room. The validity and accuracy of this mathematical correlation have been proven by comparing the results with available experimental data in the configuration studied and a good agreement was recorded.

Sedimentation from flocculated suspensions in the presence of settling‐driven gravitational interface instabilities

AbstractWe experimentally examine sedimentation from a freshwater suspension of clay flocs overlying saltwater in the presence of gravitational instabilities. The study seeks to determine: (1) if flocculation hampers or alters interface instability formation; (2) how the removal rates of sediment from the buoyant layer compare to those predicted by individual floc settling; and (3) whether or not it is possible to develop a model for effective settling velocity. The experiments were conducted in a tank at isothermal conditions. All experiments were initially stably stratified but later developed instabilities near the interface that grew into downward convecting plumes of fluid and sediment. Throughout, we measured sediment concentration in the upper and lower layers, floc size, and plume descent rates. The data showed that flocculation modifies the mixture settling velocity, and therefore shifts the mode of interface instability from double‐diffusive (what one would expect from unflocculated clay) to settling‐driven leaking and Rayleigh‐Taylor instability formation. Removal rates of sediment from the upper layer in the presence of these instabilities were on the same order of magnitude as those predicted by individual floc settling. However, removal rates were found to better correlate with the speed of the interface plumes. A simple force‐balance model was found to be capable of reasonably describing plume velocity based on concentration in the buoyant layer. This relation, coupled with a critical Grashof number and geometry relations, allowed us to develop a model for the effective settling velocity of the mixture based solely on integral values of the upper layer.

A Dynamically Computed Convective Time Scale for the Kain–Fritsch Convective Parameterization Scheme

Abstract Many convective parameterization schemes define a convective adjustment time scale τ as the time allowed for dissipation of convective available potential energy (CAPE). The Kain–Fritsch scheme defines τ based on an estimate of the advective time period for deep convective clouds within a grid cell, with limits of 1800 and 3600 s, based on practical cloud-lifetime considerations. In simulations from the Weather Research and Forecasting (WRF) Model using 12-km grid spacing, the value of τ often defaults to the lower limit, resulting in relatively rapid thermodynamics adjustments and high precipitation rates. Herein, a new computation for τ in the Kain–Fritsch scheme is implemented based on the depth of the buoyant layer and the convective velocity scale. This new τ formulation is applied using 12- and 36-km model grid spacing in conjunction with a previous modification that takes into account the radiation effects of parameterized convective clouds. The dynamically computed convective adjustment time scale is shown to reduce the precipitation bias by approximately 15% while also providing improved simulations of inland rainfall from tropical storms.

A pattern-oriented model for assessing effects of weather and freshwater discharge on black coral (Antipathes fiordensis) distribution in a fjord

Doubtful Sound and other New Zealand fjords are unique in that they provide suitable habitat for a black coral species (Antipathes fiordensis) at depths as shallow as 4m. Research suggests the upper depth limit at which black corals can survive in Doubtful Sound is controlled by gradients in salinity (as opposed to light levels) within buoyant low-salinity layers (LSL). The thickness of the LSL in Doubtful Sound varies along the fjord and fluctuates as a function of rain, wind and freshwater tailrace discharge from the Manapouri Hydroelectric Power Station. A pattern-oriented survivorship model was developed to predict mortality and upper-depth distribution of black corals in Doubtful Sound in response to changes in the LSL. Model parameters were estimated using observed patterns of black coral distribution and time-series salinity measurements over a range of depths. Predicted upper depth limits in Doubtful Sound and a reference fjord (Milford Sound) were validated against field observations of black coral depth distributions on the adjacent rock walls. The model accurately forecasted depths of corals in mid to outer regions of Doubtful Sound, but underestimated upper depth limits in the inner region of both fjords. The discrepancies in inner fjord locations suggest that other factors, such as sedimentation, are also limiting establishment of long-lived corals in some locations. Data from hydrodynamic simulations of the LSL in Doubtful Sound were fed into the survivorship model to investigate black coral distributions under varying rain, wind and tailrace discharge scenarios. Results indicate that weather, rather than tailrace discharge, drives long-term patterns in the vertical distribution of black corals in Doubtful Sound.

Viscosity scaling of fingering instability in finite slices with Korteweg stress

We perform linear stability analyses and direct numerical simulations to investigate the influence of the dynamic viscosity on viscous fingering instability in miscible slices. Selecting the characteristic scales appropriately, the importance of the magnitude of the dynamic viscosity of individual fluids on viscous fingering in miscible slice has been shown in the context of the transient interfacial tension. Further, we have confirmed this result for immiscible fluids and shown the similarities between viscous fingering in immiscible and miscible slices with transient interfacial tension. In a more general setting, the findings of this letter will be very useful for different viscous flows, such as displacement of a buoyant miscible layers in a vertical Hele-Shaw cell, viscous fingering instability with viscosity-dependent dispersion, etc.

In situ measurement shows ocean boundary layer physical processes control catastrophic global warming.

The infrared greenhouse gas heat trap at the top of the atmosphere controls anthropogenic global warming (AGW) heat balance. Processes at the top of the ocean similarly control the 93% of AGW in the oceans. The tropics are a global year-round ocean heat source. Heat is transported in the ocean by sinking brine from tropical evaporation and polar freezing. Buoyant freshwater and ice barriers limit heat loss from the surface layer. The almost completely unstudied ocean surface skin is critically important to understanding global warming and climate change processes. Studies to date have concentrated on atmospheric warming mainly from land-air data. In this paper we present the first hourly meridional 3m and surface observations in the equatorial Pacific from Tahiti to Hawaii for direct measurement of evaporation and ocean boundary layer heat trapping. We relate this to poleward heat and freshwater transport and ocean warming moderation by basal icemelt of floating ice explored in a second paper [1].We show heat sequestration below 3m in the hypersaline (&gt;35.5‰) southern hemisphere (SH) is limited to ~6MJm-2day-1 but evaporation is 7.3mmm-2day--1, at salinity ~36.4‰ and temperature &gt;28ºC. In the northern hemisphere (NH) tropics the corresponding figures are ~12 MJm-2day-1 and ~4.5mmm-2day--1. Equatorial upwelling and the 50m deep Bering Strait limit buoyant surface outflow from the North Pacific.We found pairs of counter-rotating vertical meridional tropical cells (MTCs), ~300-1200km wide, ~100m deep form separate SH and NH systems with little cross-equatorial flux. Counter-rotating Lagrangian wind-driven gyres transport heat and freshwater polewards in seasonally and tidally moderated stratified surface waters. The zonal geostrophic balance is maintained by the Equatorial Undercurrent (EUC) with an eastbound core ~140cms-1 and density ~25.0 at 50-150m.Global warming and polar icemelt has been underestimated from wrong assumptions of the processes in the top 3m of oceans. These are the unverified beliefs that ocean evaporation depends on windspeed and relative humidity that the ocean is well mixed to 10m depths, and by neglect of water density determined by both salinity and temperature. Temperature measurement to ±0.01ºC is required to account for the 3000x greater volumetric heat capacity of seawater to air (3.9x106: 1.3x103Jm-3°C-1). Most SST data are to atmospheric standards (&gt;±0.5°C). Evaporation depends only on temperature (Clausius-Clapeyron). Heat sequestration depends on the buoyant surface layer processes and underlying density gradient. Eleven interconnected counter-rotating Lagrangian wind-driven surface gyres form a global circulation system that carries buoyant surface water masses at speeds much higher than Eulerian geostrophic currents. Polar ice may erode year-round from basal melting from warm subsurface water.This explains contrasting Arctic/Antarctic warming impacts. We suggest many more in situ 3m timeseries especially meridional ones are needed to confirm our findings. In a second paper on centennial daily surface timeseries we show ocean surface warming trend rate post about 1976-1986 is ~0.037ºCyr-1, i.e. &gt;1ºC in 20 years [1]. We suggest global warming research be concentrated on the top of the ocean through multidisciplinary timeseries fieldwork verification, monitoring and modeling. This would best be conducted through a cost-efficient dynamic adaptive scientific management for rapid determination of mitigation and adaptation strategies. Reducing troposphere greenhouse gases can only reduce warming. Mitigation maybe possible through heat energy extraction from geothermal, ocean, tidal and solar sources.

A study on flow stratification in a space using displacement ventilation

This paper presents a theoretical analysis approach and experimental results on the stratified flow in a reduced-scale model using mechanical and natural displacement ventilation. Theoretical analysis is based on fundamental conservation equations and turbulent plume theory. The salt-bath technique is employed to conduct the analogous experiments to building ventilation problems and the reduced-scale acrylic model is used to observe the flow patterns in the laboratory. The light-attenuation method is used to analyze flow stratification in the analogous experiments. The model is divided into two rooms, which have the same cross-section area and volume, by an interior divider. The room having a buoyancy source is denoted as the ‘forced room’, and the other room is denoted as the ‘supply room’, which provides a constant flow rate into the space for mechanical displacement ventilation cases. This research focuses on analyzing convection flow properties and stratification distribution in the forced room. The research results show that the stratified flow in the forced room is controlled by the supply flow rate and slightly by the buoyancy source strength for mechanical displacement ventilation. The flow properties are normalized to be dimensionless parameters under the condition of a fixed buoyancy flux, and the dimensionless interface level and the dimensionless reduced gravity of the buoyant layer change with the dimensionless flow rate. As the supply flow rate increases, the stability of stratification becomes weak and there is an intermediate stratified layer formed between the fresh ambient and polluted buoyant layers. This study shows that the stability of stratification and the thickness of the intermediate stratified layer are dependent on the ratio of buoyancy force to inertia force in the room using displacement ventilation.