Physical Criterion Research Articles

Coalescence time of ellipsoidal-wobbling bubbles at surfactant-free interface: Experimental analysis and collision criteria

This work experimentally analyzed bubbles' coalescence with an air-water interface in the ellipsoidal-wobbling regime for different bubble approach velocities, encompassing the ranges of Eötvös, Weber, and Reynolds numbers of 2-3, 1-4, and 500-1100, respectively. We employed high-speed imaging to measure the bubbles' size, shape, velocity, coalescence time, and number of bounces at the interface. We investigated two criteria to determine the beginning of bubble-interface interaction (“collision”): the physical criterion, based on the distance between the bubble top surface and the interface, and the hydrodynamic criterion, based on the bubble velocity. Gamma distributions represented the coalescence times of bubbles at their terminal velocities well. We found a linear relationship between the coalescence time and the number of bounces. The hydrodynamic criterion was more consistent in representing our data on coalescence time.

Coastal water quality dynamics of the Red Sea, southeast coast of Egypt using GeoAI and ChatGPT

The Red Sea coastal environment of Halayeb and Shalateen area is renowned for its abundant marine flora and fauna. It also holds significant economic and cultural importance for local communities. However, this region is currently confronted with various challenges, including climate change and habitat destruction. To effectively address and mitigate these issues, advanced technologies that offer a holistic understanding of the area's environmental conditions are required. This paper applies the integration of Geospatial Artificial Intelligence (GeoAI) and ChatGPT to study the Red Sea Coastal water quality dynamics of Halayeb and Shalateen Area. Landsat imagery and Copernicus Marine Service were used to retrieve area boundaries and monitor the physicochemical characteristics of the coastal water respectively. ChatGPT was utilized to generate Python code that facilitates the creation of optimal distribution maps for each physical and chemical property criterion. The Python codes were incorporated into the Python program within the ArcGIS 10.7.1 and executed to generate the desired maps representing the dynamics of physical and chemical properties. It was found an observed fluctuation in chemical properties next to the coastline around the mouth of two main wadies; Wadi Hudain, and Wadi Da'eb. The degree of stability increased away from the coast toward the deep water. That proved the effect of the runoff on the seawater, as the runoff plays an essential role in the water state, especially in such semi-closed water bodies like the Red Sea where the flashfloods are the main source that can enrich water with sediment and nutrients. The state of seawater in terms of physical properties was not characterized by a specific pattern. The distribution of physical parameters in the Red Sea is influenced by factors such as regional climate variations, monsoonal winds, and local topography. This paper serves as a stepping stone for future research endeavors, exploring the full potential of this integrated approach. It can be concluded that the fusion of GeoAI and ChatGPT technologies has the potential to revolutionize our approach to studying and managing the coastal environment.

Study on Characteristics of Steam Chamber and Factors Influencing Nitrogen-Assisted Vertical–Horizontal Steam Drainage Development

With the notable achievements attained through the implementation of steam-assisted gravity drainage (SAGD), the vertical–horizontal steam drive (VHSD) emerges as a pivotal technological advancement aimed at significantly enhancing the efficiency of thin reservoir heavy oil recovery subsequent to steam cyclic stimulation. The inclusion of nitrogen assistance has proven effective in enhancing the efficacy of gravity drainage techniques in reservoir development. However, it is noteworthy that this method has only led to improvements in approximately 50% of the well groups within the observed field. The comprehensive evaluation index of VHSD was proposed, and as the objective function, it was determined that the greatest contribution to the VHSD technique lies in oil saturation, accounting for 40% of the overall evaluations. This differs from conventional SAGD operations, where reservoir thickness serves as the primary determinant. Building upon an enhanced physical simulation similarity criterion, two comparative injection scheme experiments were conducted to explore the impact of nitrogen injection on the performance of VHSD and the characteristics of the steam chamber. Nitrogen is distributed in the vicinity of the steam chamber, leading to the formation of a dual mechanism characterized by ‘top heat insulation and lateral traction’ on the steam chamber. The lateral traction accounts for approximately 25% of the team chamber volume. Additionally, the inducement of nitrogen causes a downward displacement of crude oil, resulting in its accumulation within the high-temperature region of the steam chamber. This, in turn, enhances the contact area between the high-temperature steam and the crude oil, ultimately leading to improvement in production efficiency. Further validation of the impact of nitrogen on steam lateral traction and interlayer steam drainage within the reservoir was confirmed using Xinjiang oilfield testing. The well temperature increased from 75 °C to 130 °C.

Edge of chaos as critical local symmetry breaking in dissipative nonautonomous systems

The fully nonlinear notion of resonance−geometrical resonance−in the general context of dissipative systems subjected to spatially periodic phase-modulated potentials is discussed. It is demonstrated that there is an exact local invariant associated with each geometrical resonance solution which reduces to the system’s energy when the potential is stationary. The geometrical resonance solutions represent a local symmetry whose critical breaking leads to a new analytical criterion for the onset of chaotic instabilities. This physical criterion is deduced in the co-moving frame from the local energy conservation over the shortest significant timescale. Remarkably, the new physical criterion for the onset of chaotic instabilities is shown to be valid over large regions of parameter space, thus being useful beyond the scope of current mathematical techniques. More importantly, the present theory helps to understand the unreasonable effectiveness of the Melnikov’s method beyond the perturbative regime.

Проблемы работодательской правосубъектности несовершеннолетних в возрасте от 14 до 18 лет

The article focuses on the employer’s legal personality of minors aged 14 to 18 years old provided for in part 10 of Art. 20 of the Labor Code of the Russian Federation, which allows them to act as employers in labor rela-tions. The relevance of the work topic is emphasized by its underdevelopment in the science of labor law, which requires further study of this category. The article emphasizes the reasons of unreasonable vesting by the legislator of minors with the right to be employers, which are as follows: inconsistency of the legislator in determining the age criterion of employer’s legal personality for these persons, construction of the studied norm by analogy with Art. 26 of the Civil Code of the Russian Federation, ignoring such essential factors as mental (volitional criterion) and physiological (physical criterion) state of health of persons under the age of 18. This made it possible to conclude that the labor law regulating the acquisition of employer’s legal personality by individuals is not devoid of serious shortcomings that require its improvement, in this regard, the author pro-posed measures to eliminate them.

ИССЛЕДОВАНИЕ НАПРЯЖЕННО-ДЕФОРМИРОВАННОГО СОСТОЯНИЯ МАТЕРИЛА В ОБЛАСТИ ВЕРШИНЫ ТРЕЩИНЫ, РАСПОЛОЖЕННОЙ В ЗОНЕ КОНСТРУКТИВНОГО КОНЦЕНТРАТОРА

The influence of the stress concentrator is studied due to the design features of the welded metal structure of a loader crane on the stress-strain state of the material in the fracture process zone. Within the framework of the research, a physical criterion using the basic mechanical properties of the material is applied. A normal tear-off crack is considered under uniaxial loading conditions. FEM analysis of T-joint and lap welded joint models, as creating the highest stress concentration in metal structures of loader cranes, is carried out. A comparative analysis of calculation results for models with a crack in the concentrator area and models with a crack in a smooth plate is performed. The influence of the concentrator and its several parameters on the stress stiffness at the crack tip is shown. A general averaged estimation of the concentrator influence on the material stress state in the fracture process zone is proposed. Recommendations on taking into account the presence of the concentrator in analytical calculations are given.

Experimental study on equilibrium initiation and extension of multiple clusters of fractures based on true triaxial physical simulation

In the context of tight sandstone reservoirs in the Ordos Basin characterized by compact and heterogeneous rock formations, conventional fracturing techniques yield monolithic fracture shapes, rendering 3D reservoir reconstruction unattainable. This study investigates the principles governing balanced initiation and propagation of fractures in multi-cluster fracturing within unconventional fracturing technology. Employing a large-scale true triaxial simulation experiment system, we utilize the dimensional analysis method (π theorem) to design a physical simulation experiment similarity criterion. Through various experimental adjustments involving proportioning, curing, and mechanical testing, we generate an artificially cured rock mass with mechanical parameters akin to the target layer. The rock mass is maintained at a size of 30 cm × 30 cm × 30 cm. Systematic physical simulation experiments on unconventional volume fracturing are carried out using the 30 cm-sized dense sandstone outcrop rock mass. Taking the conventional fracturing technology as a reference and manipulating experimental conditions and design parameters, we simulate the non-equilibrium initiation and extension behaviors of fracturing fractures under five unconventional volume fracturing technologies, namely hydraulic pulse pretreatment, temporary plugging between clusters, flow-limiting method, cyclic loading and unloading, and pulse intermittent fracturing. Through this, we elucidate the non-equilibrium initiation and extension laws governing multi-cluster fractures. Comparative analysis with conventional fracturing, known for inducing stress interference on fractures and inhibiting their expansion, revels that the five unconventional volume fracturing techniques mitigate stress interference in multi-cluster fracturing. This promotes uniform fracture initiation and expansion, facilitating the creation of complex fractures and larger reconstructed volumes. Among these techniques, inter-cluster block fracturing stands out for its exceptional ability to generate complex fracture networks. The research culminates in the development and refinement of a balanced fracture and extension control technique tailored for multiple cluster fractures in bulk fracturing. This technique significantly contributes to enhancing the degree of 3D reconstruction achievable in unconventional tight oil and gas reservoirs.

Simplified Stability-Based Transition Transport Modeling for Unstructured Computational Fluid Dynamics

Inspired by the model framework, a new -based model was developed and implemented into an unstructured Reynolds-averaged Navier–Stokes (RANS) code. The new model applies a modified version of the -transport equation of the model. This new implementation applies an alternative local formulation for the pressure-gradient parameter that allows the local assessment of the transition criterion within the boundary layer and, thereby, simplifies the model and increases the accuracy of the transition onset location. The resulting prediction approach is robust, user-friendly, and suitable for unstructured RANS solvers with high parallelization. To attain a wide application range of the prediction method, while keeping the simplicity of the approach, a physical path-independent transition criterion was adopted, which was calibrated based on linear stability theory results. The approach was successfully validated against experimental data for various relevant test cases. In addition, results were also compared with results obtained with the model and, for some cases, with the method, which showed a strong similarity in the predictions of the method and the new model.

Research on Physical Model and Criterion of Loose Strands in Tension Stringing Construction

In tension stringing construction, the conductor defects of loose strand often occur, which affects the construction quality and conductor life. There is no suitable method to express the physical state of such loose strand at present. Through the study of the loose strands section of the conductor, the physical model of the loose strands of the conductor is established, and the physical calculation formula of scattered strands and lantern included in loose strands defect is proposed, as well as the discrimination coefficient of the scattered strands k 1 and the lantern k 2 . 3D scanning technology of industrial CT was used to scan and model the loose strand samples of JL/G1A-630/45-45/7 and JL1/G2A-1250/100-84/19 ACSR obtained from the loose strand reproduction test of conductor. The CT scanning model is evenly intercepted to measure multiple sections, and the scattered strands coefficient and the lantern coefficient are calculated. The results show that: When k 1 and k 2 ≥ 1.2, the scattered strands and lantern defects of the conductor are more obvious, which can be used as a criterion.

Зависимость показателей эксплуатационных свойств азотированных сталей от структурного состояния поверхностного слоя

The results of structural and tribological studies of steels and alloys of pearlite, martensitic and austenitic classes using dif-ferent types of pretreatment and nitriding modes are presented. The results of tribological tests and metallophysical studies made it possible to evaluate the effectiveness of each of used treatment methods and to identify the characteristics of the structural state of the nitrided layer, contributing to an increase in the operational properties of steels in friction and wear conditions. A comprehensive physical and mechanical criterion has been developed to evaluate friction components nitrid-ing efficiency.

Computational study of mechanical stresses in a cell interacting with micromechanical cues and microfabrication of such cues in Nervous system-on-Chips

We have investigated the laser micromachining of microsieves with 3D micropore geometries. We hypothesize that mechanical cues resulting from the positioning and machining of ablated holes inside a pyramidal microcavity can influence the direction of neuronal outgrowth and instruct stem cell-derived neural networks in their differentiation processes. We narrowed the number of variations in device fabrication by developing a numerical model to estimate the stress distribution in a cell interacting with the laser-tailored unique 3D geometry of a microsieve’s pore. Our model is composed of two components: a continuous component (consisting of the membrane, cytoplasm, and nucleus) and a tensegrity structural component (consisting of the cytoskeleton, nucleoskeleton, and intermediate filaments). The final values of the mechanical properties of the components are selected after evaluating the shape of the continuous cell model when a gravity load is applied and are compared to the shape of a cell on a glass substrate after 3 h. In addition, a physical criterion implying that the cell should not slip through a hole with a bottom aperture of 3.5 μm is also set as a constraint. Among all the possible one- or multi-hole configurations, six cases appeared promising in influencing the polarization process of the cell. These configurations were selected, fabricated, and characterized using scanning electron microscopy. Fabricated microsieves consist of a 20 μm thick Norland Optical Adhesive 81 (NOA81) foil with an array of inverted pyramidal microcavities, which are opened by means of KrF 248 nm laser ablation. By changing the position of the laser beam spot on the cavities (center, slope, or corner) as well as the direction of laser beam with respect to the NOA81 microcavity foil (top side or back side), different ablation configurations yielded a variety of geometries of the 3D micropores. In the one-hole configurations when the shot is from the top side, to make the desired diameter of 3.5 μm (or less) of an opening, 1500 laser pulses are sufficient for the center and slope openings. This requirement is around 2000 laser pulses when the aperture is positioned in the corner. In back side ablation processes, the required number of pulses for through-holes at the center, slope, and corner positions are 1200, 1800, and 1800 pulses, respectively. In conclusion, we developed a microsieve platform that allows us to tailor the 3D topography of individual micropores according to the selection of cases guided by our numerical stress distribution models.

Modeling of spark ignition in gaseous mixtures using adaptive mesh refinement coupled to the thickened flame model

In standard LES of spark ignition using the thickened flame model (TFM) and a static mesh, in other words without the use of adaptive mesh refinement (AMR), a progressive increase of the thickening factor F from unity to the nominal value is a consequence of the progressive increase of the cell size away from the spark plug. If the refined mesh is limited to a small region around the spark plug, the computational cost is limited but F will increase very rapidly as soon as the flame leaves the spark region, leading to an erroneous prediction of the total heat release rate as shown in this study. Conversely, using a large refined mesh region will allow such a progressive increase of F but at the cost of a strongly increased computational cost. To solve this issue, two new spark ignition models called TFM-AMR-I and TFM-AMR-I-Ftrans are proposed for TFM. These models are based on TFM-AMR Mehl et al.(2021) which employs AMR to ensure the desired thickening level and a constant number of grid points across the flame. It also uses a realistic spark plug energy model as in Colin et al.(2019). To avoid the aforementioned issue, a physical criterion is proposed to start the increase of F only when the flame kernel can be considered self-sustained. As this criterion is given by a model transport equation, the possible convection of the kernel outside the spark region doesn’t prevent the model to work properly. Secondly, in both models the increase of F is no more dictated by the cell size of the static mesh but it is given by an additional transport equation that controls the growth rate of F in time.These models are applied to the laminar propane/air ignition experiment presented in Colin et al.(2019). It is first shown that the experimental MIE is correctly recovered when using a DNS type resolution, that is, F=1 at any time. Then both proposed LES ignition models are applied to the same case: they recover correctly the MIE of the DNS provided the stretch correction of Quillatre (2014) is applied, which confirms the need to correct the effect of stretch with TFM. At the same time, TFM-AMR-I under-predicts the total heat release rate, which is attributed to the jump of the thickening factor at each AMR level removal. On the contrary, TFM-AMR-I-Ftrans compares better with the DNS, which is attributed to the continuous evolution of F with this model. Finally, it is shown that both models lead to a computational time reduction of a factor between 2 and 6 compared to static mesh TFM simulations.

Perceived Stress and Quality of Life in Healthcare Workers of Non-COVID-19-Designated Hospitals During the COVID-19 Pandemic in Ukraine

Introduction. Healthcare workers are more vulnerable to negative influences of the Covid-19 pandemic than cross-border travelers as they experience greater occupational stress, exacerbated by the possibility of self-contamination or contamination of their relatives through direct contact with patients, reduced social communication, deterioration in self-care and quality of life due to lack of energy and time.
 The aim of the study was to assess the level of stress and quality of life in healthcare workers of non-COVID-19-designated hospitals in Ukraine during the COVID-19 pandemic.
 Materials and Methods. There was carried out a case-control study that included 150 respondents divided into three groups: experimental groups (EG) 1 and 2 comprised 50 physicians and 50 nurses of non-COVID-19-designated hospitals, respectively; the control group (CG) included 50 healthy individuals not working in the healthcare field. The data were collected using paper questionnaires involving sociodemographic questions, the Perceived Stress Scale, and the 36-Item Short Form Health Survey.
 Results. EG 1 and EG 2 had significantly increased stress levels as compared to the CG. Physical functioning criterion in EG 2 was significantly lower than those in EG 1 and the CG. Vitality and social functioning indicators were significantly lower in EG 1 and EG 2 as compared to the CG. Quality of mental health was worse in EG 1 than in the CG.
 Conclusions. During the COVID-19 pandemic, healthcare workers of non-COVID-19-designated hospitals experienced a significant reorganization of their work environment, which required them to adjust rapidly to new conditions and psychological difficulties. The medical staff was found to have an increased level of perceived stress and decreased quality of life, which could affect the quality of medical care. Our findings suggest that the COVID-19 pandemic necessitates the development and implementation of stress coping measures to improve mental and physical health of healthcare workers, which can be used to achieve proper work and rest routines, create a microclimate within the team, and restore the work-life balance.

Analiza kamienia cementowego w otworze wiertniczym oraz nowoczesna strategia doboru systemów cementacyjnych

The long road of development of cementing technology, which ensured the development of cement compositions, methods of preparation, chemical treatment and transportation of binder material into the annular space of the well, did not solve all the problems of high-quality isolation of the layers. A reasonable physical criterion and exact methods for assessing the quality of fastening have not been found either as it is very difficult to reproduce downhole conditions during experimental work in order to establish a large number of simultaneously acting factors on the durability of the borehole lining. In this regard, there is no generally accepted method for testing cementing materials in the world and the issue of the necessary strength of stone from various cementing materials intended for cementing columns and installing cement bridges has not been resolved. The world's leading drilling service companies (Schlumberger, Halliburton, etc.) do not use special cements such as UCG, OCG, etc., but prepare their mixture specifically for each cementing process, based on one base cement selected for these oil and gas fields. Various types of weighting agents, lighteners and other mixing additives with the base cement provide the well-specific grouting system. All over the world, these systems are being prepared at specially equipped bases. The conducted studies give grounds to assert that high-quality normal, lightweight and weighted cement mortars can be obtained on the basis of local raw materials, provided that modern technology and equipment are available.

An analysis of three-dimensional patterns of experimental detonation cells

The notions of regularity and characteristic width of detonation cells are revisited based on crossed analyses of experimental front-view and longitudinal recordings obtained with the soot-plate technique. Tubes with cross-sections of different shapes, namely round, triangular and square, but the same surface area of 16 cm2, are used to detonate the stable mixture 2H2 + O2 + 2Ar with the initial pressure p0 varying from 15 kPa to 100 kPa and the initial temperature T0=294 K. The longitudinal recordings show the well-known regular arrangements for this mixture for all cross-section shapes and p0, but the front-view recordings show irregular patterns except for the square shape and low-enough p0. There are fewer cells in the round tube, more in the square one, and their average widths and relative differences decrease with increasing p0. All front-view cell patterns become irregular and independent of the cross-section shapes with increasing p0. The cellular dynamics at the walls of a tube is thus not representative of that on the whole detonation front, and longitudinal soot traces alone are not sufficient for describing the cellular structure. An analysis based on graph theory proposes that a tessellation of regular hexagons can model a large set of irregular front-view cells. A cell count on an experimental front-view recording thus defines an average cell width and an intrinsic but high minimum error for this width. Its resulting large sensitivity to the parameters of a simple Arrhenius rate of chemical progress indicates that detailed schemes of chemical kinetics and more advanced conceptual tools than a single length are necessary for characterizing the three-dimensional structures of detonation cells. The Voronoi tessellation supplemented with a physical criterion for the surface density of randomly-distributed point sources could represent a step forward.

Association between Lebanese Mediterranean Diet and Frailty in Community-Dwelling Lebanese Older Adults-A Preliminary Study.

Discrepancies in the characteristics of the food components of a Mediterranean diet exist based on the country of origin. In Lebanon, a traditional Mediterranean diet emphasizes the high intakes of fruits (including dried), vegetables, burghol, and dairy products. Therefore, this cross-sectional study aimed to explore the association between adherence to the Lebanese Mediterranean diet (LMD) and frailty among older adults in Lebanon. A total of 112 community-dwelling older adults aged ≥65 years were recruited. Demographic and clinical characteristics were collected through face-to-face interviews. A 61-item food frequency questionnaire (FFQ) was used to collect dietary intake data, and adherence to LMD was calculated. Physical frailty was defined by the presence of three out of the five criterion: weight loss, weakness, exhaustion, slowness, and low activity. Binary logistic regression was used to examine the relationship between LMD adherence and frailty while adjusting for several confounders. The participants’ mean age was 73 ± 12.8 and 65% were females. Sixteen (14.3%) individuals were identified as frail. Frail individuals were significantly older (p = 0.001), depressed (p < 0.001), at risk of cognitive impairment (p = 0.006), and reported polypharmacy (p = 0.003). No significant association was found between LMD adherence and frailty in fully adjusted models (OR = 0.195; 95% CI: 0.033–1.154; p = 0.071 when categorical and OR = 0.856; 95% CI: 0.668–1.097; p = 0.218 when continuous). We also performed additional analyses with a modified frailty index where house chores were not considered as part of leisure activities of the physical activity criterion. The results showed that a higher LMD adherence was associated with a significantly decreased frailty prevalence (OR = 0.123, 95% CI: 0.022–0.676, p = 0.016 when categorical and OR = 0.773, 95% CI 0.608–0.983, p = 0.036). Larger, longitudinal studies are needed to clarify the relationship between the adherence to the Lebanese Mediterranean diet and frailty in Lebanese older adults.

Health Services and Patient Satisfaction in IRAN during the COVID-19 Pandemic: A Methodology Based on Analytic Hierarchy Process and Artificial Neural Network

The aim of this study is to identify and classify the most important factors affecting patient satisfaction in the COVID-19 pandemic crisis considering economic effects. This is an analytical study using the analytic hierarchy process (AHP) method and ANN-MLP (Artificial neural network based on multilayer perceptron model as a supervised learning algorithm) as an innovative methodology. The questionnaire was completed by 72 healthcare experts (N = 72). The inter-class correlation (ICC) coefficient value was confirmed in terms of consistency to determine sampling reliability. The findings show that interpersonal care and organizational characteristics have the greatest and least influence, respectively. Furthermore, the observations confirm that the highest and lowest effective sub-criteria, respectively, are patient safety climate and accessibility. Based on the study’s objective and general context, it can be claimed that private hospitals outperformed public hospitals in terms of patient satisfaction during the COVID-19 pandemic. Focusing on performance sensitivity analysis shows that, among the proposed criteria to achieve the study objective, the physical environment criterion had the highest difference in private and public hospitals, followed by the interpersonal care criterion. Furthermore, we used a multilayer perceptron algorithm to assess the accuracy of the model and distinguish private and public hospitals as a novelty approach. Overfitting results in finding an MLP model which is reliable, and the accuracy of the model is acceptable.

Generalized quantum Vlasov equation for particle creation and unitary dynamics

The loss of time-translational invariance caused by a time-dependent external agent leads to particle creation effects in quantum field theory. This phenomenon results in ambiguities when selecting the quantum vacuum of the canonical quantization. In this work we analyze how the time evolution of the number of created particles depends on these ambiguities when external agents are spatially homogeneous. In particular, we generalize the standard quantum Vlasov equation in order to accommodate in its formulation the possibility of having different choices of vacuum, including adiabatic vacua. This study leads us to propose a new physical criterion stronger than the unitary implementation of the dynamics in order to reduce the quantization ambiguities.

Optimal self-assembly of lipid nanoparticles (LNP) in a ring micromixer

Lipid nanoparticles (LNPs) for RNA and DNA delivery have attracted considerable attention for their ability to treat a broad range of diseases and to vectorize mRNA for COVID vaccines. LNPs are produced by mixing biomolecules and lipids, which self-assemble to form the desired structure. In this domain, microfluidics shows clear advantages: high mixing quality, low-stress conditions, and fast preparation. Studies of LNPs produced in micromixers have revealed, in certain ranges of flow rates, a degradation in performance in terms of size, monodispersity and encapsulation efficiency. In this study, we focus on the ring micromixer, which is well adapted to high throughput. We reveal three regimes, side-by-side, transitional and highly mixed, that control the mixing performance of the device. Furthermore, using cryo-TEM and biochemical analysis, we show that the mixing performances are strongly correlated to the characteristics of the LNPs we produce. We emphasize the importance of the flow-rate ratio and propose a physical criterion based on the onset of temporal instabilities for producing LNPs with optimal characteristics in terms of geometry, monodispersity and encapsulation yield. These criteria are generally applicable.

Predicting the Thermal Regime of the Sebou River Estuary (Morocco) Using a One-Dimensional Model (HEC-RAS 5.0)

Temperature is regarded as one of the most important variables for aquatic life, as well as a key physical criterion of water quality, due to its role in a variety of chemical, physical, and biological processes. We chose the HEC-RAS tool to model the thermal regime of the Sebou-Kenitra river estuary because it is impossible to determine the spatiotemporal evolution of temperature in watercourses using traditional methods such as single measurements or interpolation due to the influence of several factors, including hydraulic, tidal rhythm, upstream contributions, and intrusion. The main goal of this research is to develop and test the “HEC-RAS” model with the aim of better understanding thermal dynamics and predicting the spatiotemporal variation of the Sebou river estuary temperature, using the energy transport equation and a variety of input data such as initial temperature, air temperature, wind speed, and dispersion coefficient. The HEC-RAS model, which takes into account many meteorological and geophysical elements and provides an overview of the thermal situation at our study site “the Sebou river estuary,” has also been acknowledged for its deterministic role. We illustrated the impact of meteorological and tidal data on spatiotemporal temperature change at numerous places in the Sebou river estuary by using this model.