Influence of environmental factors on the spread of COVID-19 in Saudi Arabia

Background Coronavirus disease 2019 (COVID-19) has affected millions of people worldwide. The infection is mostly spread through the inhalation of infected droplets. Saudi Arabia is a vast country having different climatic conditions. Methods The study evaluated the influence of environmental factors on the spread of COVID-19. Six zones (A to F) were classified depending on the climatic conditions. The study was conducted by retrospective analysis of COVID-19 records from the ministry of health between the months of September 2020 and August 2021. The environmental data such as average temperature (°C), humidity (%), wind speed (m/s) and sun exposure (kwh/m2) were retrieved from official sites. The data was analyzed to determine the effect of these factors on the spread of COVID-19. SPSS IBM 25 software was used to conduct the analysis and p < 0.05 was considered to indicate the significance of the results. Results According to the findings, the rate of infection was greater between April and July 2021. Six climatic zones experienced high temperatures, little humidity, consistent wind flow, and intense sun exposure throughout this time. The correlation study revealed a significant (p < 0.05) relationship between the environmental factors and the spread of COVID-19. The data suggested that during summer condition when the weather is hot, less humid, and steady wind flow with lots of sun exposure, the COVID-19 infection rate got augmented in Saudi Arabia. Poor ventilation and closed-door habitats in an air-conditioned atmosphere during this period could have played a role in human transmission. More research on air quality, population mobility and diseased condition is essential, so that precise proactive measures can be designed to limit the spread of infection in specific climatic seasons.

Aeolian transportation mechanics and mass movement of surficial beach sands – a case study on Bendi-BaruvaMineral Sand Deposit, Srikakulam District, Andhra Pradesh

Surficial sediment transportation studies carried out in the beach zone of Bendi-Baruva mineral sand deposit show that sand grains are transported by wind (saltation and suspension) beyond the high water line. The sand population of the study area contains heavy mineral sands (~20%) like ilmenite, garnet and sillimanite which covers 95% of the heavy mineral distribution with subordinate amounts of monazite, rutile, and zircon whereas light mineral sands (~80%) contain mostly quartz. Due to the sorted nature of these beach and dune sands the whole spectra falls within a specific range of grain size which shows a bi-modal distribution, primary mode at 0.025cm and secondary at 0.015cm. Due to this variation in density and grain size, mass of these sand particles vary resulting in differential transportation in any energy regime. In the study area, on the beach near the frontal dunes, surficial concentration of garnet grains are observed in patches having an average thickness 0.2cm i.e. around ten times of the dominant grain diameter. This surficial enrichment of garnet grains resting on a semi-uniform sand surface is the result of differential transportation of the dominant mineral grains. As more than 80% of the grain size population show a dominant grain size of 0.025cm, the wind flow parameters for the whole population is standardized with mean grain diameter (D) of 0.025cm. Mass of dominant individual minerals arrived from the grain counting technique was tallied with the theoretical mass considering spherical shape of the grains indicates a difference of mass to be within 5%. For ease of calculation and generalization the grains were considered to be spherical and their theoretical masses were taken into consideration in calculations. Considering the whole spectra of mineralogical distribution, a theoretical mass group distribution for dominant different minerals of different dominant grain sizes were formulated and total six mass groups were identified. Because quartz (~80%), ilmenite, sillimanite and garnet (together ~20%) are the most abundant, their positions were identified specifically in the theoretical mass groups and only these are considered for further discussion. To analyse wind velocity and pressure at different heights from the surface, a sediment trap was fabricated using piezo-electric sensors. A tail was attached to orient the device parallel to the wind flow so that the piezo surfaces always face the wind flow at 900 angle. The device records pressure data and converts those into voltage. Using the velocity data, macroscopic physical quantities of aeolian transportation were calculated for the study area, which empirically show the effect of mass in differential transportation of the dominant minerals that gives rise to these surficial garnet patches.

Аtmospheric wind flow around the mountain landscape in the vicinity of Danang airport and flight safety issues

Wind boundary layer flow over the mountain landscape and large structures located around runways (RWs) creates coherent vortex structures (CVSs) that can cross a glideslope and airspace in the vicinity of an airport. The aircraft, encountering a vortex structure, experiences significant changes of the aerodynamic forces and moments, what is especially hazardous due to proximity to terrain. From a mathematical point of view, the solution of this problem presents a challenge due to extremely large space – time scale of the phenomenon, the lack of relevant atmospheric models, as well as comprehensive initial – boundary conditions in numerical modeling. In this paper, a composite solution is constructed: the CVSs area generation is computed in sufficient details within the framework of the grid method. Based on the data obtained in the approximation of analytical functions, an initial vortex structure is formed, the evolution and stochastics of which are modeled within the potential approximation by means of Rankine vortices. The evaluation of the forces and moments increment from the impact of vortex structures on the aircraft was carried out by the panel method using the engineering approach. As an example, the CVSs, resulting from wind flow around the mountainous area of the Son Tra Peninsula, that is located short of RWs 35R-17L and 35L-17R of Da Nang airport, are investigated. To improve the computational grids quality and verify the method of solving the boundary value problem for the Reynolds-averaged Navier-Stokes equations, we used the criteria based on the principle of maximum pressure, requiring Q-parameter positivity property in the vortices cores and flow separation regions. A CVS related aviation event, involving a passenger aircraft MC-21, is studied. The aircraft, after takeoff from RW 35R-17L setting the course close to the direction of the vortex wind structure axis from the Son Tra Peninsula, encountered the mountainous area CVS.

Variations of flow direction in solar wind streams of different types

Studying the direction of the solar wind flow is a topical problem of space weather forecasting. As a rule, the quiet and uniform solar wind propagates radially, but significant changes in the solar wind flow direction can be observed, for example, in compression regions before the interplanetary coronal mass ejections (Sheath) and Corotating Interaction Regions (CIR) that precede high-speed streams from coronal holes. In this study, we perform a statistical analysis of the longitude (φ) and latitude (θ) flow direction angles and their variations on different time scales (30 s and 3600 s) in solar wind large-scale streams of different types, using WIND spacecraft data. We also examine the relationships of the value and standard deviations SD of the flow direction angles with various solar wind parameters, regardless of the solar wind type. We have established that maximum values of longitude and latitude angle modulus, as well as their variations, are observed for Sheath, CIR, and Rare, with the probability of large deviations from the radial direction (>5°) increasing. The dependence on the solar wind type is shown to decrease with scale. We have also found that the probability of large values of SD(θ) and SD(φ) increases with increasing proton temperature (Tp) in the range 5–10 eV and with increasing proton velocity (Vp) in the range 400–500 km/s.

Variations of flow direction in solar wind streams of different types

Studying the direction of the solar wind flow is a topical problem of space weather forecasting. As a rule, the quiet and uniform solar wind propagates radially, but significant changes in the solar wind flow direction can be observed, for example, in compression regions before the interplanetary coronal mass ejections (Sheath) and Corotating Interaction Regions (CIR) that precede high-speed streams from coronal holes. In this study, we perform a statistical analysis of the longitude (φ) and latitude (θ) flow direction angles and their variations on different time scales (30 s and 3600 s) in solar wind large-scale streams of different types, using WIND spacecraft data. We also examine the relationships of the value and standard deviations SD of the flow direction angles with various solar wind parameters, regardless of the solar wind type. We have established that maximum values of longitude and latitude angle modulus, as well as their variations, are observed for Sheath, CIR, and Rare, with the probability of large deviations from the radial direction (>5°) increasing. The dependence on the solar wind type is shown to decrease with scale. We have also found that the probability of large values of SD(θ) and SD(φ) increases with increasing proton temperature (Tp) in the range 5–10 eV and with increasing proton velocity (Vp) in the range 400–500 km/s.

Wind Environment Study of High-rise Residential Building by using Multiple Computational Tools

<p>Wind environment is a key element of sustainable design of architecture. Concerning major trends of climate changes and urbanizations, this research aims to study the relationships between the influences on wind environments and variables related to forms and configurations of contemporary high-rise residential buildings. A novel methodology consisting of parametric design, CFD simulation, and analysis is developed by integrating multiple computational tools, and the evaluation criteria. The integration provides abundant functions and an efficient modelling-simulation-analysis solution for iterative comparison studies. By using a parametric modelling method, building models can be created automatically to help in mesh generation for CFD simulations; the actual influenced areas with different wind velocity ranges can be calculated and compared quantitatively through the calculations of wind-velocity magnitudes from simulation results, at each pixel location on a rendered section. Based on the architectural morphology of Building-Unit Forms (BUFs) and Building-Cluster Configurations (BCCs) in an area classified in China as a Hot-Summer and Cold-Winter Area (HSCWA), the parametric design sets up a bridge between building variables and CFD simulations. A series of representative BUFs and BCCs of high-rise residential buildings are designed for CFD simulations by establishing parametric design system based on the building categorization study. In the wind environment studies, influences of buildings are evaluated based on the wind-velocity magnitudes according to the criteria. The trends of influences can be studied through iterative analysis of several cases with different variables. The mechanisms are illustrated through the air-pressure magnitudes and the wind-flow streamlines. In the wind environment studies of BUFs, relationships between influences on wind environments and building variables of three representative BUFs are studied, including square form, rectangular form, and ‘T’ form. The results of the BUFs studies can be summarized: (1) the influences on wind environments increase as the height and windward length are increased, because more winds are obstructed by the increasing windward surface; (2) the influences on wind environments decrease as the ratio of length and width is increased before the ratio reaches a particular value, because influenced air-pressure area is decreased; (3) the influences on the wind environments decrease as the bulge-part sizes of the ‘T’-form buildings increase, because the increases of bulge-part sizes help to divide winds and lead them to flow around the buildings; (4) the outdoor ventilation is improved as the rotation angle increases, because the non-vertical windward surface promotes the wind flow. In the wind environment studies of BCCs, relationships between influences on wind environments and building variables of three representative BCCs are studied, including scattered configuration, linear configuration, and curvilinear configuration. Results of the BCCs studies can be summarized: (1) the outdoor ventilation of scattered configuration is the best, because it is relatively easy for winds to flow around the scattered building units; (2) the outdoor ventilation can be improved as the longitudinal distance and staggered distance are increased, because the larger building interval promotes winds to flow through the building cluster; (3) for curvilinear configuration, the convex surface on the windward side can promote the wind flow, and the concave surface on the windward side can obstruct the wind flow. The results of the BUFs studies and the BCCs studies all show that the increases of the windward projective areas of buildings can increase the influences on wind environments, because more winds are obstructed. Therefore, the relationships between the influences on wind environments and the building variables of the BUFs and BCCs can be discovered, which can give information to the optimization of wind environments. In summary, the thesis presents a challenging and significant research that contributes original knowledge for wind environment studies in the urban micro climate. And the knowledge is universal and applicable to the practical design projects and also beneficial to the sustainability.</p>

Wind Environment Study of High-rise Residential Building by using Multiple Computational Tools

<p>Wind environment is a key element of sustainable design of architecture. Concerning major trends of climate changes and urbanizations, this research aims to study the relationships between the influences on wind environments and variables related to forms and configurations of contemporary high-rise residential buildings. A novel methodology consisting of parametric design, CFD simulation, and analysis is developed by integrating multiple computational tools, and the evaluation criteria. The integration provides abundant functions and an efficient modelling-simulation-analysis solution for iterative comparison studies. By using a parametric modelling method, building models can be created automatically to help in mesh generation for CFD simulations; the actual influenced areas with different wind velocity ranges can be calculated and compared quantitatively through the calculations of wind-velocity magnitudes from simulation results, at each pixel location on a rendered section. Based on the architectural morphology of Building-Unit Forms (BUFs) and Building-Cluster Configurations (BCCs) in an area classified in China as a Hot-Summer and Cold-Winter Area (HSCWA), the parametric design sets up a bridge between building variables and CFD simulations. A series of representative BUFs and BCCs of high-rise residential buildings are designed for CFD simulations by establishing parametric design system based on the building categorization study. In the wind environment studies, influences of buildings are evaluated based on the wind-velocity magnitudes according to the criteria. The trends of influences can be studied through iterative analysis of several cases with different variables. The mechanisms are illustrated through the air-pressure magnitudes and the wind-flow streamlines. In the wind environment studies of BUFs, relationships between influences on wind environments and building variables of three representative BUFs are studied, including square form, rectangular form, and ‘T’ form. The results of the BUFs studies can be summarized: (1) the influences on wind environments increase as the height and windward length are increased, because more winds are obstructed by the increasing windward surface; (2) the influences on wind environments decrease as the ratio of length and width is increased before the ratio reaches a particular value, because influenced air-pressure area is decreased; (3) the influences on the wind environments decrease as the bulge-part sizes of the ‘T’-form buildings increase, because the increases of bulge-part sizes help to divide winds and lead them to flow around the buildings; (4) the outdoor ventilation is improved as the rotation angle increases, because the non-vertical windward surface promotes the wind flow. In the wind environment studies of BCCs, relationships between influences on wind environments and building variables of three representative BCCs are studied, including scattered configuration, linear configuration, and curvilinear configuration. Results of the BCCs studies can be summarized: (1) the outdoor ventilation of scattered configuration is the best, because it is relatively easy for winds to flow around the scattered building units; (2) the outdoor ventilation can be improved as the longitudinal distance and staggered distance are increased, because the larger building interval promotes winds to flow through the building cluster; (3) for curvilinear configuration, the convex surface on the windward side can promote the wind flow, and the concave surface on the windward side can obstruct the wind flow. The results of the BUFs studies and the BCCs studies all show that the increases of the windward projective areas of buildings can increase the influences on wind environments, because more winds are obstructed. Therefore, the relationships between the influences on wind environments and the building variables of the BUFs and BCCs can be discovered, which can give information to the optimization of wind environments. In summary, the thesis presents a challenging and significant research that contributes original knowledge for wind environment studies in the urban micro climate. And the knowledge is universal and applicable to the practical design projects and also beneficial to the sustainability.</p>