Degree Of Stratification Research Articles

Experimental Investigation on Formation Mechanism of Jet Fires in Transformer Oil Filled Equipment with External Thermal Load

ABSTRACT Liquid jet fire was one of the typical fires that endangered industrial safety. Especially, the oil-filled equipment of the substation was subjected to an external thermal load, which caused liquid jet fire. However, less literature was available for the formation mechanism of liquid jet flame. Thus, this paper conducted a systematic experiment to reveal the formation mechanism of transformer oil jet fire with various heat release rates (33 kW, 73 kW, 132 kW, and 212 kW). In this paper, the formation mechanism of transformer oil jet fire was clarified. Experimental observation showed that the formation process of transformer oil jet fire can be divided into three stages. The gas–liquid two-phase flow occurred during the formation of transformer oil jet fire. The correlation between the overpressure peak and the heat release rate was established. The medium thermal response behavior can be divided into three stages. When the medium temperature reached the boiling point, the jet fire appeared. The thermal stratification model of a transformer oil jet was established. The correlation between the degree of liquid stratification and dimensionless heat release rate was established. The thermal convection and radiation determined the heat transfer mechanism of oil during the formation of jet fire.

Second-order Stokes wave-induced dynamic response and instantaneous liquefaction in a transversely isotropic and multilayered poroelastic seabed

The ocean waves exhibit obvious non-linearity with asymmetric distribution of wave crests and troughs, which could induce significantly different effect on the seabed compared to the commonly used linear wave theory. In this paper, a semi-analytical solution for a transversely isotropic and multilayered poroelastic seabed under non-linear ocean wave is proposed by virtue of the dual variable and position (DVP) method. The ocean wave and seabed are, respectively, modelled using second-order Stokes theory and Biot’s complete poroelastodynamic theory. Then the established governing equations are decoupled and solved via the powerful scalar potential functions. Making use of the DVP scheme, the layered solutions are finally gained by combining the boundary conditions of the seabed. The developed solutions are verified by comparing with existing solutions. The selected numerical examples are presented to investigate the effect of main parameters on the dynamic response of the seabed and evaluate the corresponding liquefaction potential. The results show that the anisotropic stiffness and permeability, degree of saturation and stratification have remarkable influence on the dynamic response and liquefaction behavior of the seabed. The present solution is a useful tool to estimate the stability of transversely isotropic and layered seabed sediment in the range of non-linear ocean wave.

Statistical analysis of inequality in the distribution of income and expenses of the population in the Republic of Azerbaijan

In the article, based on the information of the State Statistics Committee, an economic-statistical analysis of the unequal distribution of incomes and expenses of the population in the Republic of Azerbaijan for the period of 1995-2021 was carried out, and an absolute equality curve was constructed, which visually shows the degree of stratification of the society using the Gini index and the Lorenz curve. The results of the calculations were carried out using the MS Excel package, the income and expenses of the studied population group, as well as the statistics of the economically active population, were analyzed accordingly. At the same time, an autoregression analysis was conducted and it was learned that the model has a stationary structure with the second design difference.

Zonal winds in the gas planets driven by convection above a stably stratified layer

ABSTRACT The analysis of the recent gravity measurements of Jupiter and Saturn reveal that the zonal winds observed on their surfaces reach several thousand kilometres deep into their atmospheres. However, it remains unclear which mechanism prevents them from penetrating deeper. Recent models suggest that a stably stratified region would yield the desired effect. In this numerical study we systematically explore the dynamics of flow in a rotating spherical shell where the lower third is stably stratified while convection in the outer region drives multiple zonal winds, similar to those observed on Jupiter or Saturn. When using a rigid lower boundary condition, only an equatorial jet pair is formed without an underlying stable layer. When including a stable layer, fierce multiple jets also develop at mid to high latitudes, once the stable stratification is strong enough to effectively decouple the jet dynamics from the lower boundary. We find that the decay of the jet amplitude near the stable layer boundary is controlled by Ω/N, where Ω is the rotation rate and N the Brunt-Väisälä frequency that quantifies the degree of stable stratification. Furthermore, the penetration distance of the jets is proportional to the jet width. In the convective region, the winds are invariant along the axis of rotation, whereas their extension in the stable layer tends to become radially aligned.

Stability of axially symmetric magnetic fields in stars

Abstract The magnetic fields observed in Ap stars, white dwarfs, and neutron stars are known to be stable for long times. However, the physical conditions inside the stellar interiors that allow these states are still a matter of research. It has been formally demonstrated that both purely toroidal and purely poloidal magnetic fields develop instabilities at some point in the star. On the other hand, numerical simulations have proved the stability of roughly axisymmetric magnetic field configurations inside stably stratified stars. These configurations consist of mutually stabilizing toroidal and poloidal components in a twisted torus shape. Previous studies have proposed rough upper and lower bounds on the ratio of the magnetic energy in the toroidal and poloidal components of the magnetic field. With the purpose of mapping out the parameter space under which such configurations remain stable, we used the Pencil Code to perform 3D magnetohydrodynamic simulations of the evolution of the magnetic field in non-rotating, non-degenerate stars in which viscosity is the only dissipation mechanism, both for stars with a uniform (barotropic) and radially increasing (stably stratified) specific entropy. Furthermore, we considered different conditions regarding the degree of stable stratification and the magnetic energy in each component, roughly confirming the previously suggested stability boundaries for the magnetic field.

Effect of inhomogeneous methane-air mixtures on combustion characteristics in a constant volume combustion chamber

The inhomogeneous mixture can improve the combustion performance under certain conditions. In this study, an experimental study of turbulent stratified combustion under different background equivalent ratio conditions (0.6, 0.8, 1.0) was carried out based on a constant volume combustion chamber. Injection of pure methane to achieve stratification of gas mixture concentration, and the ignition timing was adjusted to control the mixture stratification degree. Optical diagnosis of the flame using a high-speed camera and the optical schlieren system to understand the morphological changes in flame development. Based on the combustion pressure and ion current signals to explore the effect law of stratification degree on the turbulent stratified combustion characteristics. The results of the study show that the concentration stratification of the mixture can accelerate the flame propagation speed. The leaner the background mixture concentration, the stronger the promotion effect of the mixture concentration stratification on the propagation speed. The appropriate degree of stratification is conducive to improving the stability of the flame. Turbulent stratified combustion can increase the maximum combustion pressure, shorten the combustion duration. The degree of stratification has a large effect on the ion current signal curve during the background equivalent ratio of 0.6 mixture combustion, and almost no effect when the background equivalent ratio is 1.0. The peak moment of the combustion pressure rises rate and the peak moment of the ion current signal occur almost simultaneously under different combustion conditions. The correlation between the maximum of the combustion pressure and the maximum of the ion current is approximately linear and the correlation is greater than 95%.

Effects of meander curvature in thermally stratified turbulent open-channel flow

Thermal stratification can lead to the damping of turbulence, which reduces the mixing of solutes in a fluid body. A series of direct numerical simulation (DNS) solutions sweeping through a range of four different meandering channel curvatures, from a sharp to mild curvature range, are obtained to investigate the effect of curvature on stratification in meandering thermally stratified turbulent open channel flow with an internal heat source that models radiative heating from above. Based on the DNS results, the present paper addresses two issues. First, the influence of changing curvature on the complex bi-cellular pattern of the secondary flow is investigated, including the distribution of the temperature field. Second, the effects of changing curvature on the degree of stratification are analyzed. Stratification can be characterized by the friction Richardson number Riτ and the bulk Richardson number Rib. Stratification can also be viewed in terms of the transfer of energy from mean flow kinetic energy to potential energy via buoyancy fluxes. We study the effect of curvature on stratification by investigating its effect on the friction and bulk Richardson numbers. We also study the transfers between the global potential and kinetic energy reservoirs, including the global available Ea, background Eb, and total potential energy Ep, and the domain-averaged mean kinetic and turbulent kinetic energy. It is found that, in meandering channels, with the increase in curvature, Ep increases and Riτ and Rib decrease, indicating that increasing curvature leads to a decrease in the level of stratification. On the other hand, we also find that a low curvature meandering channel has a higher level of stratification than a straight channel.

Coastal stratification and mixing on the western margin of the Gulf of Tehuantepec within a synoptic atmospheric and oceanographic environment

We present, for the first time for this region, the evolution of stratification in a 24 m depth water column in the western margin of the Gulf of Tehuantepec, northeastern tropical Pacific, during the dry season: December 2011 to March 2012. Stratification, defined here as the temperature difference observed between 5- and 24-m depth, although never equal to zero, decreased as a function of wind, but also as a function of the ambient thermal structure created by the transit of mesoscale eddies. A common wind scenario is made of the occurrence of northerlies over the central gulf, and westerlies over the western margin. As northerly winds decay, westerly winds may become dominant over the entire gulf. Stratification weakens under relatively strong northerlies over the gulf or strong westerlies over the western margin. In contrast, stratification strengths as northerly winds relax and the westerly wind on the western margin is weak or incipient. The degree of stratification is also dependent on the sign of the mesoscale eddies transiting the area; it can vanish under cyclonic circulation but become strong under anticyclonic circulation. We hypothesize that the increase of stratification on the western margin of the Gulf of Tehuantepec is the result of a two-layer circulation that develops between the gulf and its western margin during the northerly wind relaxation. Relatively warm water flows, near the surface, from the western margin towards the central gulf, and mixed relatively cold-water, flows in opposite direction below. This finding represents a novel result for this region.

Monthly and seasonal variations in the surface carbonate system and air–sea CO2 flux of the Yellow Sea

Surface carbonate chemistry in the Yellow Sea was investigated based on discrete seawater samples collected from 2017 to 2020 at the Socheongcho Ocean Research Station (S-ORS; 37.423°N, 124.738°E). Records of carbon parameters, including seawater CO2 partial pressure (pCO2), revealed considerable seasonal variations, with amplitudes comparable to those observed across the western part of the Yellow Sea. The study site acted as a modest sink (−0.13 mol C m−2 yr−1) for atmospheric CO2. Biological processes (primary production and respiration) and physical conditions (temperature and degree of stratification) determined seawater pCO2, which fluctuated on an intraseasonal timescale between oversaturated and undersaturated with respect to atmospheric pCO2. Variation in pCO2 was significant in summer, depending on the biological carbon drawdown and tidal mixing-induced upwelling (increased pCO2 up to ~1000 μatm). The intraseasonal variability in seawater pCO2 may bias estimated air–sea CO2 fluxes, if measurements with a coarser (seasonal) time resolution are used.

Centipedes (Chilopoda) in urban forest habitats: the case of the metropolitan city of Rome area (Central Italy)

Three forest fragments located along a gradient from the central area of the city (an urban historical park) to increasingly peripheral areas (a suburban nature reserve, an extraurban nature reserve) were identified in the western sectors of the Metropolitan City of Capital Rome administrative district and its surroundings (Central Italy). With the aims to describe the structural parameters of Chilopod assemblages in these forest fragments for determine their status of conservation and to evaluate the effects of some environmental variables (coverage of the canopy layer, shrub layer, herb layer, litter layer) on selected species, sampling took place by pitfall traps from June 2015 to June 2016. The relevance of these kind of studies is in precisely identifying the areas of greatest conservation value; the purpose is to provide guidelines for the planning of the ecological network of the city of Rome towards the protection of the areas inhabited by more sensitive fauna and flora elements rather than protecting as many areas as possible. Chilopods are strictly forest arthropods, therefore they are considered useful biondicators of these ecosystems. The centipede assemblage of suburban forest fragment is characterized by a greater complexity and stability compared to the centipede assemblages of central and extraurban forest fragments, both apparently in a typical state of successional stages. The distribution pattern of the centipede diversity of the study area seems to deviate from the usual patterns found in other European cities for other arthropod assemblages as well as for the centipedes, as the greater biodiversity has been recorded in the suburban forest fragment, not in the extraurban one. The suburban forest fragment is moreover characterized by a higher degree of stratification and structural complexity than the other two forest fragments, with a largest number of forest species, some of these absent both in the urban and the extraurban fragments.

Performance comparison of two water pit thermal energy storage (PTES) systems using energy, exergy, and stratification indicators

Water pit thermal energy storage systems have been demonstrated in Denmark and have proven effective in increasing the solar thermal fractions of district heating systems and in covering the mismatch between heat demand and production. This study analyzed five years of measurement data for two PTES systems in Denmark, namely Marstal and Dronninglund. Their efficiency was assessed using energy, exergy, and a seasonal efficiency indicator. The degree of stratification was investigated using the MIX number, the stratification coefficient, and a newly-introduced indicator, exergy destruction. Exergy destruction was shown to be a promising indicator for assessing stratification since it can be used to compare PTES systems with different heat losses, providing a quantitative evaluation of the amount of mixing. In addition, the seasonal efficiency was found to be suitable for estimating the long-term efficiency of combined seasonal and short-term storage systems. The storage in Dronninglund had 92% energy and 73% exergy efficiency, while Marstal had 63% energy and 48% exergy efficiency. All stratification and efficiency indicators showed that the storage in Dronninglund performed better overall than the one in Marstal.

The role of heat wave events in the occurrence and persistence of thermal stratification in the southern North Sea

Abstract. Temperature extremes not only directly affect the marine environment and ecosystems but also indirectly influence hydrodynamics and marine life. In this study, the role of heat wave events in the occurrence and persistence of thermal stratification was analysed by simulating the water temperature of the North Sea from 2011 to 2018 using a fully coupled hydrodynamic and wave model within the framework of the Geesthacht Coupled cOAstal model SysTem (GCOAST). The model results were assessed against reprocessed satellite data and in situ observations from field campaigns and fixed Marine Environmental Monitoring Network (MARNET) stations. To quantify the degree of stratification, the potential energy anomaly throughout the water column was calculated. The air temperatures and potential energy anomalies in the North Sea (excluding the Norwegian Trench and the area south of 54∘ N) were linearly correlated. Different from the northern North Sea, where the water column is stratified in the warm season each year, the southern North Sea is seasonally stratified in years when a heat wave occurs. The influences of heat waves on the occurrence of summer stratification in the southern North Sea are mainly in the form of two aspects, i.e. a rapid rise in sea surface temperature at the early stage of the heat wave period and a higher water temperature during summer than the multiyear mean. Another factor that enhances the thermal stratification in summer is the memory of the water column to cold spells earlier in the year. Differences between the seasonally stratified northern North Sea and the heat wave-induced stratified southern North Sea were ultimately attributed to changes in water depth.

Design optimization of a latent heat storage using sodium acetate trihydrate

This paper presents numerical investigations on a heat storage utilizing sodium acetate trihydrate (SAT) as phase change material (PCM). The heat storage can be used both in short-term and in long-term by utilizing stable supercooling of SAT. The store contains 137.8 kg PCM and 75 L water. Based on a validated CFD model, the flow conditions of the heat storage was analyzed. Uneven flow distribution inside the heat storage was revealed. Three design optimization methods were investigated to eliminate the uneven flow distribution. The results were analyzed using key performance indicators inclusive charging time, charged heat, degree of thermal stratification and the mixing of the heat storage. The influence of flow direction, inlet size and addition of a porous plate on the thermal performance of the heat storage were elucidated. Concerning flow direction, after moving the inlet from the bottom to the top of the storage, the time needed to completely melt the PCM was shortened by 50%. The best storage design was identified: For charge of the storage, the top inlet should be used, while for discharge, the bottom inlet should be used. Concerning the size of inlet opening, the charging time of the heat storage was reduced from 75 min to 51 min by using 3.0 mm radius instead of a 11.2 mm inlet. The small inlet size (3.0–8.0 mm) was suggested to make a uniform temperature distribution inside the heat storage. Short circuit was completely eliminated by adding a porous plate with 10% porosity. The charging time of the heat storage was shortened 28% by adding the porous plate. Finally, recommendations were proposed for different applications of the heat storage. The findings of the paper serve as a good basis for designers and manufacturers of PCM heat storages.

Faecal occult blood loss accurately predicts future detection of colorectal cancer. A prognostic model

ObjectivesTo examine the prognostic potential of repeated faecal haemoglobin (F-Hb) concentration measurements in faecal immunochemical test (FIT)-based screening for colorectal cancer (CRC).DesignPrognostic model.SettingDutch biennial FIT-based screening programme during 2014–2018.Participants265 881...

Hydroclimate changes related to thermal state of the tropical Pacific in the northern coast of the South China Sea since ∼8000 cal yr B.P.

Under the complex influences including the monsoonal climates and tropical hydrological cycle, the features and forcing mechanisms of precipitation changes in the tropical monsoon regions remain controversial. The northern coast of the South China Sea (NCSCS), connecting the South China Sea (SCS) and the Pearl River Estuary (PRE), is a critical area providing reliable tropical precipitation records and probing the possible forcing mechanism of tropical precipitation, benefitted from its high deposition rate and hydroclimatic sensitivity. Here, δ18O variations of planktonic (δ18OG. ruber) and benthic foraminifera (δ18OC. lobatulus) were investigated respectively to reconstruct a high-resolution low-latitude precipitation record from the core 17NH-NC3 in the NCSCS. The results show a distinct δ18O difference between δ18OG. ruber and δ18OC. lobatulus, not only with respect to values, but also with respect to trends in some time intervals. The clear difference between the planktonic and benthic foraminifera (Δδ18Ob-p) illustrates the significant vertical salinity stratification. And the temporal trend of Δδ18Ob-p indicates the degree of salinity stratification variated since the mid-Holocene. We assume that the degree of stratification in the NCSCS was mainly controlled by tropical precipitation changes. Thus, the trend of Δδ18Ob-p values could indicate the temporal change of the tropical precipitation. The precipitation record of our research area is closely related to the tropical atmosphere–ocean dynamics stimulated by sea surface temperature (SST) changes of the tropical Pacific zone, analogous to the El Niño–Southern Oscillation (ENSO) events. During the mid-Holocene (from 8260 to 5180 cal yr B.P.), the sustainable higher Δδ18Ob-p values (>1.23‰) suggested a large amount of precipitation, pointing to a sustained state of La Niña-like, which is associated with lasted higher difference between Western SST and Eastern SST (W-E SST gradient) in the equatorial Pacific. Since 5180 cal yr B.P., the decreasing Δδ18Ob-p indicates less low-latitude precipitation, which can be ascribed to an El Niño-like mean state arising from decreased W-E SST gradient. Our study provides a new continuous high-resolution archive of low-latitude precipitation in the tropical monsoon region since 8260 cal yr B.P. And this record highlights that the thermal state of the tropical Pacific most likely adjusted the low-latitude precipitation since the mid-Holocene.

Effect of Particle Interactions on the Assembly of Drying Colloidal Mixtures.

The effects of particle interactions on the size segregation and assembly of colloidal mixtures during drying were investigated. A cationic surfactant was added to a binary latex/silica colloidal dispersion that has been shown to self-stratify upon drying at room temperature. Atomic force microscopy was used to show that the change in particle interactions due to the presence of surfactants reduced the degree of stratification and, in some cases, suppressed the effect altogether. Colloidal dispersions containing higher surfactant concentrations can undergo a complete morphology change, resulting instead in the formation of armored particles consisting of latex particles coated with smaller silica nanoparticles. To further prove that armored particles are produced and that stratification is suppressed, cross-sectional images were produced with energy-dispersive X-ray spectroscopy and confocal fluorescence microscopy. The growth of armored particles was also measured using dynamic light scattering. To complement this research, Brownian dynamics simulations were used to model the drying. By tuning the particle interactions to make them more attractive, the simulations showed the presence of armored particles, and the size segregation process was hindered. The prevention of segregation also results in enhanced transparency of the colloidal films. Overall, this research proves that there is a link between particle interactions and size segregation in drying colloidal blends and provides a valuable tool to control the assembly of different film architectures using an extremely simple method.

Lateral changes of organic matter preservation in the lacustrine Qingshankou Formation (Cretaceous Songliao Basin, NE China): Evidence for basin segmentation

Organic matter-rich intervals in the Cretaceous succession of the large non-marine Songliao Basin in northeastern China (covered area ~ 87 × 103 km2), including the Turonian–Coniacian Qingshankou Formation (K2qn), offer unique records to study the role of global (e.g., climate, “limno-eustasy”) and regional (tectonics, basin geometry) controls on organic matter accumulation. A wealth of scientific papers concentrate on the vertical variations in organic matter (OM) preservation along the Southeastern Uplift of the basin, which hosts its most prolific source rock intervals. However, the corresponding K2qn interval in the Central Depression is less well studied, and no lateral correlation between both parts of the basin based on direct information from well logs and drill cores exists to date. Hence, the dominant influencing factors causing lateral changes organic-richness and source potential are not yet fully understood. Basin geometry effects in particular could not be evaluated in detail, as highly resolved seismic data is lacking for the transitional zone between the Southeastern Uplift and Central Depression. This paper uses Integrated Prediction Error Filter Analysis of wireline logs together with petrographical and geochemical data from drill cores of two key wells in the Central Depression and Southeastern Uplift areas for a detailed correlation of the K2qn1 interval and its three sub-units (Sq1 to Sq3). Bulk geochemical (e.g., total organic carbon vs. total sulphur), biomarker (ratios of pristane vs. phytane, dibenzothiophene vs. phenanthrene, and total steroid vs. hopanoid compounds; Gammacerane Index; abundance of 4-methylsteranes and C29 steranes), and petrographical (e.g., maceral composition; framboidal pyrite size) data to trace changes in the depositional conditions. All data sources support a higher degree of salinity stratification and more intense anoxia at the Southeastern Uplift compared to the Central Depression particularly during accumulation of the lowermost and most organic-rich Sq1 sub-unit. These observations indicate that two depocenters may have existed during times of Sq1 deposition, and that the pronounced basin separation inhibited marine incursions from the Southeastern Uplift to the Central Depression. During deposition of the overlying Sq2 and Sq3 sub-units, a low relative lake level and dry climatic conditions likely prevailed. The geochemical data suggest similar dysoxic brackish-fresh water conditions in both depocenters. Moreover, the well log correlation indicates that a gradually connected basin may have formed at this time, reducing the effects of two separate depocenters on sediment accumulation and organic matter preservation. Thus, this study provides the first direct evidence that apart from global factors, basin segmentation strongly controlled the distribution of organic matter-rich rocks within the Qingshankou Formation.

Liquid Biopsy for Patient Characterization in Cardiovascular Disease: Verification against Markers of Cytochrome P450 and P-Glycoprotein Activities.

Precision dosing strategies require accounting for between‐patient variability in pharmacokinetics together with subsequent pharmacodynamic differences. Liquid biopsy is a valuable new approach to diagnose disease prior to the appearance of clinical signs and symptoms, potentially circumventing invasive tissue biopsies. However, the possibility of quantitative grading of biomarkers, as opposed to simply confirming their presence or absence, is relatively new. In this study, we aimed to verify expression measurements of cytochrome P450 (CYP) enzymes and the transporter P‐glycoprotein (P‐gp) in liquid biopsy against genotype and activity phenotype (assessed by the Geneva cocktail approach) in 30 acutely ill patients with cardiovascular disease in a hospital setting. After accounting for exosomal shedding, expression in liquid biopsy correlated with activity phenotype for CYP1A2, CYP2B6, CYP2C9, CYP3A, and P‐gp (r = 0.44–0.70, P ≤ 0.05). Although genotype offered a degree of stratification, large variability (coefficient of variation (CV)) in activity (up to 157%) and expression in liquid biopsy (up to 117%) was observed within each genotype, indicating a mismatch between genotype and phenotype. Further, exosome screening revealed expression of 497 targets relevant to drug metabolism and disposition (159 enzymes and 336 transporters), as well as 20 molecular drug targets. Although there were no functional data available to correlate against these large‐scale measurements, assessment of disease perturbation from healthy baseline was possible. Verification of liquid biopsy against activity phenotype is important to further individualize modeling approaches that aspire to achieve precision dosing from the start of drug treatment without the need for multiple rounds of dose optimization.

Investigating Thermal Stratification in a Hot Water Storage Tank during Charging Mode

Hot water storage (HWS) tanks are the sensible energy storage systems used to accumulate thermal energy in water for later use. In the present study, a vertical cylindrical HWS tank equipped with three heat exchanger coils to harness energy from different energy sources is numerically investigated. A 2-D axisymmetric model is developed in ANSYS Fluent to simulate and study the dynamic behavior of the HWS tank during charging. Three operating cases with one heating source functioning at a time are analyzed to determine the degree of thermal stratification. Transient temperature and velocity distributions are discussed for the qualitative and quantitative analysis of mixing and stratification in each case. The results assist the design engineers and end-users in determining effective modes of HWS operation with maximum stratification, thus, system efficiency.

Africa's food security: Malnutrition and obesity

Food security in Africa is characterized by pronounced regional aspects, with the largest number of hungry people living in sub-Saharan Africa. The continent accounts for a third of all hungry people in the world, and this indicator demonstrates an upward trend in recent years. At the same time, a significant part of the population suffers from obesity. This alarming twofold nature of the food problem on the continent is rooted in poverty and a high degree of social stratification, insufficient economic growth, low productivity of agriculture and food industry, lack of investments in these sectors of economy, military and other conflicts, climate shocks, etc. The article explores the current trends of this problem at the international, continental and national levels. Attention is paid to the inclusiveness vector of food systems, taking into account the need to introduce advanced innovations, including digital ones, into agriculture and the food industry. Special attention is focused on the tracks of food systems transformation according to the official representatives of African countries at the UN Summit held in September 2021. The need to attract investments in sectors of the economy, not only involved in food production, but also capable of providing employment to eradicate the extreme poverty and, as a consequence, malnutrition is emphasized. The desire of a number of African states to reflect in their national programs intention to increase the production of agricultural raw materials and food, and to develop intra-African and global cooperation to enhance the resilience to climate change is positively assessed. Such intentions are in line with global concepts of transforming food systems to eradicate hunger.