Search

In this paper, the fictitious domain method with continuation by lower coefficients for the model of the atmospheric boundary layer is mathematically substantiated. The theorem of existence and uniqueness of the solution of the auxiliary problem of the fictitious domain method for the equations of the boundary layer of the atmosphere is shown. The practical part is considered - the spread of harmful impurities in the atmosphere from point sources, taking into account the inhomogeneity of the underlying surface on the basis of the atmospheric boundary layer model. [ABSTRACT FROM AUTHOR]

A space shuttle experiences extremely intense aerodynamic heating during its reentry into the Earth's atmosphere due to sudden compression of the air near the surface of the vehicle as well as due to viscous dissipation. To protect the vehicle from these enormous thermal loads, a thermal protection system has to be devised so that components inside the space shuttle are not harmed. In order to design a suitable thermal protection system, it is imperative to determine the thermal response of the vehicle. The paper involves discussion on a program developed to calculate the same and plot the temperature vs. time graph for the stagnation point of the space shuttle re-entering into the atmosphere. This can also be extended to the windward and leeward regions by using existing correlations. The program requires atmospheric data & space shuttle trajectory details such as time, altitude, velocity as input and the program logic is derived from the basic one dimensional heat balance relation. [ABSTRACT FROM AUTHOR]

The spread of air pollutants in the atmospheric boundary layer is mainly conditioned by complex dynamic processes of the air mass movement and turbulent diffusion. Therefore, in meeting the challenges of monitoring and forecasting the ecological conditions of the atmosphere, first of all, it is necessary to take into account the air flow characteristics and the laws governing their changes. In this regard, one of the essential aspects in studying of the air flow structure is consideration of the dependence of the wind profile on the atmospheric stability and surface roughness. Thus, this work purpose is to study the influence of the vertical wind profile on the process of the spread of harmful emissions in the atmosphere based on the developed mathematical tools and GIS technologies. The results of computational experiments on determination the air flow characteristics at given heights and at various values of the ground-level wind speed and the roughness coefficient are presented in the paper, as well as the results of numerical calculations demonstrating the influence of the horizontal and vertical components of the wind speed on the distribution of suspended aerosol impurities in the considered region. [ABSTRACT FROM AUTHOR]

Due to increasing concentrations of anthropogenic carbon dioxide in the atmosphere, the problem of climate change due to global warming is becoming biggest concern. According to latest report of Intergovernmental Panel on Climate Change (IPCC), it is indicated that to constraint warming at 1.5 oC, global anthropogenic CO2 emissions would need to minimized by 45% till 2030 from 2010 levels and become net zero by 2050. One way to do this is by reducing the concentration of carbon dioxide from the atmosphere. The promising technology which could reduce CO2 concentrations from the atmosphere is the CO2 capture and storage (CCS) technology. The CCS technology involves the method of capturing effluent CO2 emitted on large scale from sources like power stations and prevent it from entering into atmosphere. Further, the captured CO2 is stored in subsurface geological formations from where it is transported to the desired site through pipelines, ships etc. for industrial and Enhanced Oil Recovery process (EOR). Low level of experience and awareness about technology in society negatively impact the successful deployment CCS projects. It is recognized that renewable power (such as wind, solar, etc.) represents only one element of technologies that will be required to deliver a technically and economically feasible energy system. In this context, CCS is known to play a vital role, providing significant value through flexible operation. However, despite of wide applications and its technical advantages, CCS has not yet been implemented on a larger scale with the ambitions formed a decade ago. This paper aims to review the importance of CCS projects in the global scenario by understanding various advantages that this technology offers to the people and various factors like environmental, technical, social and economic factors affecting the implementation of CCS technology which will describe the feasibility of this technology on a larger scale in the particular region about which was thought nearly a decade ago. [ABSTRACT FROM AUTHOR]

Peat swamp forests contain large carbon deposits which in turn if caught fire, will release large amount of carbon dioxide into the atmosphere. Besides, this results in haze. Therefore, it is increasingly important to preserve this peat swamp as much as possible. We have witnessed over the years the fire occurrence in the peat swamp forests. This has contributed exposing peatland areas more, thereby allowing greenhouse gases to be released into the atmosphere. Therefore, to date, there have been extensive investigations how peatland fire can be prevented. In order to monitor and avoid fire out-breaking in peat swamp forests, in this paper we propose a LoRa based remote monitoring system. In our solution, we developed two Remote Sensing Clusters (RSCs), which are comprised of different sensor probes in order to collect remotely parameters that are crucial for understanding the condition of a peatland. This remote monitoring solution takes advantage of Cloud technologies in order to understand the pattern and holistic view of the situation in a peatland. This solution is the first of its kind deployed in peatland of Brunei Darussalam. Our findings are based on the data from the test-bed deployed in a peatland area indicate that the proposed solution can successfully obtain data with high reliability and accuracy. [ABSTRACT FROM AUTHOR]

Striving to maintain or even reduce the concentration of CO2 in the Earth's atmosphere makes it necessary to introduce "new" fuel carriers for use in vehicles. Therefore, efforts are being made to introduce new fuel carriers, specifically e-fuels. However, one should not forget about the existing solutions in this aspect, i.e. about biofuels. Usually, the introduction of new fuel carriers results in the development of internal combustion engines in two ways. One is to adapt the engine to the new fuel and the other is to adapt the new fuel to the existing engines. There are also indirect actions, i.e. that new engine solutions are useful both in the use of existing fuels and new fuels. Usually, such solutions concern the engine equipment or even just a change in the way of controlling the processes taking place in the engine. Engine accessories include: so-called internal catalyst. In this solution, some elements of the engine's combustion chamber, such as glow plugs, are covered with a material constituting a carrier for the catalyst. In principle, the solution is to lead to a more complete combustion of fuel, thus reducing its consumption and, consequently, reducing CO2 emissions. This paper presents the impact of the application of this solution on CO2 emissions determined in the RDE test and discusses the possibility of achieving the intended goal in natural operation, i.e. with long-term use of vehicles. The results of the analyzes indicate a potentially positive impact of the use of an internal catalyst on reducing fuel consumption and, consequently, on reducing CO2 emissions. [ABSTRACT FROM AUTHOR]

The paper looks at experience drawn from soil landings of Soviet «Venera 9-14» and «Vega 1-2» landers. The experience can be useful for developing joint Russian-American mission «Venera-D» with the aim of delivering a longlasting automatic space lander to the surface of Venus. By landing the paper means the final moment of lander's descent in the atmosphere, when the lander directly contacts the soil. The reason for successful landings on Venus soil of Soviet «Venera 9-14» and «Vega 1-2» landers is explained. 8 landers with toroidal landing gear made successful landings in the period of ten years. Recommendations for developing future systems for landing on Venusian soil are given. [ABSTRACT FROM AUTHOR]

HCl is a dangerous gas product of garbage power plant, which is able to cause corrosion on the heated surface. PVC is the main source of HCl in garbage power plant. The combustion characteristics and dechlorination of polyvinyl chloride (PVC) play an important role in guiding the anti-corrosion work of garbage power plant. In this paper, TG-FTIR was used to make qualitative and quantitative analysis of chlorine release characteristics in the combustion of polyvinyl chloride (PVC). The thermogravimetry of PVC with different mass was systematically studied. The HCl removal efficiency of different mass ratios of CaCO3, CaO, Ca(OH)2 and kaolin under air atmosphere and O2/ CO2 atmosphere was studied. When the mass of PVC was more than 10mg, the weightlessness trend changed. The HCl removal efficiency increased with the proportion of absorbent, and the removal efficiency of Ca(OH)2 was the best. Oxygen had a great influence on the HCl removal efficiency of absorbent. The higher the proportion of oxygen, the higher the dechlorination efficiency. [ABSTRACT FROM AUTHOR]

LEO satellites (low earth orbit) have a short operational life in space, on average up to 6 years. This is due to the limited quantity of propellant which is used to correct the attitude of the satellite. When the propellant runs out, the attitude can't be adjusted/corrected anymore, so that the satellite drops from space and disintegrates in the earth's atmosphere. To extend the operational life of the LEO satellite, a propulsion system was developed by COMOTI Research & Development Institute. The system consists of the following main components: the parabolic mirror, a cold N2 tank, a propellant tank, valve and nozzle. The light from the sun is reflected by the parabolic mirror onto the propellant tank, which is fed with cold N2 gas from the N² tank. The propellant tank is mounted in the focal axis of the mirror. The N2 inside the propellant tank heats up, and when the desired pressure is reached, the valve opens and lets the N2 hot gas at 20 bar pressure exit through the nozzle. The reaction force obtained through this mode changes the attitude of the satellite. The advantage of this system is that it extends the life of the LEO satellites by 30% over the initial lifetime of 6 years, because it uses a hot gas propulsion system which means that less gas is used to obtain the same force as the conventional cold gas propulsion system. In this paper, the development of the parabolic mirror will be described, the mirror being a critical component in the new advanced LEO satellite propulsion system. [ABSTRACT FROM AUTHOR]

The water vapor content in atmosphere plays very important role in climate. In this paper the application of GPS signal in meteorology is discussed, which is useful technique that is used to estimate the perceptible water vapor of atmosphere. In this paper various algorithms like artificial neural network, support vector machine and multiple linear regression are use to predict perceptible water vapor. The comparative studies in terms of root mean square error and mean absolute errors are also carried out for all the algorithms. [ABSTRACT FROM AUTHOR]

Impact of aircraft on the atmosphere studied specifically their effect as a source of air and water pollution and how they contribute to the transmission or spread of diseases such as Covid 19. Aircraft engines generate various gases like carbon dioxide (CO2), including around 70% of the exhaust, and water vapor (H2O), which provides about 30%. Lower than 1% of this exhaust is consists of pollutants such as oxides of nitrogen (NOx), sulfur oxides (SOx), monoxide of carbon (CO), and especially combusted or unburned hydrocarbons (HC), particulate matter (PM), and other components. In addition, many pollutants formed in combustion convert when they are emitted into the atmosphere. All these emissions are a significant source that contributes to environmental pollution. Also, in our current days, we notice the spread of Coronavirus significantly with the increasing cases of travel and movement between governorates and countries, which makes transportation in general one of the causes of its spread as this virus travels through the air and thus affects human health in a very negative way. Statistical analysis of the impact of aircraft on air and water pollution and the problems of COVID 19 have been investigated. With the rapid development of equipment and technologies used in airplanes, and therefore current-days, airport transmission has been widespread attention with a focus on social and economic well-being, environmental activity, and protection towards sustainability. [ABSTRACT FROM AUTHOR]

Debates on the role of coral reefs, whether as a carbon source or carbon sink, started in the early 1990s. These debates continue until today, especially with the increasing concern of global climate change and global warming. Although several studies have been done to calculate the flux of pCO2 between reefs and the atmosphere, there is no clear evidence whether the coral reef is a source or sink. This paper reviews the development of studies of carbon flux of reefs, with how pCO2 is different in several reef type habitats and assess if geographical latitude of reef affected the flux of CO2. In general, coral reefs act as a carbon source to the atmosphere. However, this role depends on the habitat type of reef, whether they are coral-dominated or algal-dominated reef. The geographical location of reefs may also affect CO2 flux between reefs and the atmosphere. [ABSTRACT FROM AUTHOR]

Changing the physical conditions of the Earth's atmosphere include temperature and distribution of rainfall, which has a wide impact on various sectors of human life. According to the Indonesia Food Security Monitoring Bulletin, Komodo Meteorological Station in East Nusa Tenggara (hereafter denoted as NTT) Province in Indonesia has reported that Komodo was the one of first priority in the classification of districts experiencing drought impacts from climate change that occurred in Indonesia. The study aimed to climate projection in Komodo using the Quantile Matching Bootstrap (QMB) method, which is the block bootstrap simulation technique combined with a quantile prediction and matching method for simulating future daily climate data. The projected data is influenced by the relationship of predictors derived from the Global Climate Models to the observed data. The study was carried out by examining daily rainfall and daily maximum temperature observed data from Komodo Meteorological Station. In this paper, the performance of the QMB approach is improved by three different quantiles i.e. 10th, 50th, and 90th percentiles. The result for QMB produces the average coverage rate for the prediction intervals of around 80%. By using out of sample validation techniques, the results show that this method has successfully projected daily rainfall and daily maximum temperature during rainy season as well as transition from dry season to rainy season. [ABSTRACT FROM AUTHOR]

This paper discusses the calculation analysis of the possibility of creation of a probe for long-term contact study of the Neptune atmosphere on the basis a thermal balloon with a nuclear source of heat. The dependences of the required total mass of the probe on the payload mass have been obtained, that shows the possibility of creating such a probe weighing up to 2 tons. [ABSTRACT FROM AUTHOR]

In present paper Ti-Nb alloys produced via high-energy powder metallurgy method were studied. Ti-Nb alloys were obtained in form of layers on Ti substrate. The energy source was an electron beam emitted to the atmosphere, penetrating into deep layers of the powder. Electron energy was 1.4 MeV. It is shown that it is possible to produce alloys with predictable elemental and phase compositions via relativistic electron beam. Depending on the content of Nb, such phases as α′, α″ or β are formed. Produced alloys are non-toxic for cells. Due to this, manufacturing of small medical implants from this material is possible. [ABSTRACT FROM AUTHOR]

In scramjet engine the mixing mechanism of fuel and atmospheric air is very complicated, because the fuel have time in milliseconds for mixing with atmospheric air in combustion chamber having supersonic speed. Mixing efficiency of fuel and atmospheric air depends on mainly these parameters: Aspect ratio of injector, vibration amplitude, shock type, number of injector, jet to transverse flow momentum flux ratio, injector geometry, injection angle, molecular weight, incoming air stream angle, jet to transverse flow pressure ratio, spacing variation, mass flow rate of fuel etc. here is a very brief study of these parameters from previously done research on these parameters for the improvement of mixing efficiency. The mixing process have the significant role for the working of engine, and mixing between the atmospheric air and the jet fuel is significant factor for improving the overall thrust of the engine. The results obtained by study of papers are obtained by the 3D-Reynolds Average-Nervier-Stokes(RANS) equations along with the 2-equation k−ω shear-stress-transport (SST) turbulence model. Engine having multi air jets have 60% more mixing efficiency than single air jet, thus if the jets are increased, the mixing efficiency of engine can also be increased up to 150% by changing jet from 1 to 16. When using delta shape of injector the mixing efficiency is inversely proportional to the pressure ratio. When the fuel is injected inside the combustor from the top and bottom walls of the engine efficiency of mixing in reacting zone is higher than the single wall injection and in comparison to parallel flow, the transverse type flow is better as the atmospheric air jet can penetrate smoothly in the fuel jets and mixes well in less time. Hence this study of parameters and their effects on mixing can enhance the efficiency of mixing in engine. [ABSTRACT FROM AUTHOR]

This paper reviews the structure and behavior of the magnetosphere and discusses the current challenges in understanding the physics of the magnetosphere. The major problem is to find the appropriate model of the interaction of the solar wind with the geomagnetic field that is in agreement with observations. It is recommended that interdisciplinary collaborative painstaking research will lead to full understanding of magnetospheric physics as well as throw more light on the causes of magnetic storms, which influence earth’s atmosphere and may have negative adverse effects on human lives. [ABSTRACT FROM AUTHOR]

We propose that the aerosols in the atmosphere form layers of varying refractivity. In this paper, we used proven dispersion model alongside the unified number to determine the dynamics of the aerosol transport. The inability of scientist to calculate the atmospheric constant over an area has lead to frequent failures of ground measuring devices e.g. radiosonde, weather stations in developing regions is worrisome. From literatures, established projects like AERONET, AMMA e.t.c. are burdened by same challenge. At the moment, AERONET or AMMA database shows a large volume of data loss. With only about 47% data set available to scientist, it is evident that accurate nowcast or forecast cannot be guaranteed. Upon numerical simulations, it revealed that the atmospheric constant over Lagos-Nigeria is a1 = 1.175 , a2 = 0.88, n1 = 0.2926 and n2 = 0.3573. Lagos lies within the latitude of 6.465°N and longitude of 3.406°E. [ABSTRACT FROM AUTHOR]

Ammonium bisulfate (HSO4-)(NH3) ion is extremely unstable thermodynamically. However, larger stable (H2SO4)n(HSO4)(NH3)m clusters have been observed in laboratory experiments under atmospherically relevant conditions. In the present paper, we investigate stabilization of (H2SO4)n(HSO4-)(NH3)m clusters by NH3 using the Density Functional Theory (DFT), discuss structural trends, elucidate the stabilization mechanism, report new thermochemical data and explore their implications. In particular, we show that stable (H2SO4)n(HSO4-)(NH3)m clusters in the atmosphere are formed via addition of NH3 to (H2SO4)n(HSO4-) at n >2 and that the most abundant (H2SO4)n(HSO4-)(NH3)m ions contain one and two NH3 molecules, respectively. [ABSTRACT FROM AUTHOR]

The paper considers the idea of reducing near-Earth space debris by dumping expended stages into the Earth’s atmosphere. The problem of an impulse transfer between the parking circular orbit of an artificial Earth satellite and the target elliptical orbit is being solved. [ABSTRACT FROM AUTHOR]

We investigate how much the Newtonian-scale gravity within alternative coupling theory agrees with our understanding of Earth's atmosphere. We compare the atmospheric pressure structure predicted by the Minimal Exponential Measure (MEMe) model with one from US Standard Atmosphere 1976 model which deviates less than 10% from observation. By using Bayesian analysis via Markov-chain Monte Carlo, we found that, to be able to consistently reproduce our current understanding of Earth's atmosphere structure, the parameter q should yield |q| < 3.06 × 10−14m3J−1 in 2σ credibility, comparable to the constraint from GW170817 standard siren. We also compare this value with bounds from Eddington-inspired Born-Infeld gravity, which share a similar Poisson equation in Newtonian-scale. [ABSTRACT FROM AUTHOR]

Microwaves are usually in the range of a few to ten centimeters with the wavelengths used by remote sensing radars to monitor Earth's atmosphere. The radar pulse loses energy as they travel in the space at a rate proportional to the beamwidth. The beam spread significantly by the time it reaches the earth. Synthetic aperture radars are the solution to this problem since the outcome will greatly change. Synthetic aperture radars were designed to circumvent natural aperture radar limitations. Such systems obtain a strong azimuth resolution which is not based on the slant but does use small antennas and fairly long wavelengths. [ABSTRACT FROM AUTHOR]

Several organic metal halide perovskites are very sensitive to a humid atmosphere. Indeed, in the present work, we shown, throughout experimental analyses, that exposure for 60 days to relatively high humidity (> 55%) drops main physical properties of the synthesized MAPbI3 powder perovskite. In fact, the decomposition or degradation of the MAPbI3 perovskite has been confirmed by the appearance of a PbI2 diffraction peak in the XRD pattern at 12.65° and its absorption onset at 520 nm. Moreover, the morphological aspect shows clearly a whole change of the surface after 60 days of exposure at humid environment [ABSTRACT FROM AUTHOR]

The Earth's greenhouse gases absorb heat, a rise in greenhouse gas emissions have resulted in global warming, which is affecting the planet's climate in numerous ways. The aim of this research is to study the effect of greenhouse gases on the temperature of the two layers of the atmosphere (troposphere and mesosphere) with the presence of solar radiation effect by taking into account the climate change. The monthly data for GHGs, solar radiation and temperature are taken for the period (2000-2018) above the capital Beijing (latitude 40˚N; longitude 116˚E) in China. The results of data analysis show that, in the tropospheric layer the greenhouse gases have increased and also accompanied by an increase in temperature, an increase in temperature appears despite the decrease in solar rays, and this is strong evidence that greenhouse gases have a significant impact on temperatures, also the increase in greenhouse gases and decrease in solar radiation have a cooling effect on the mesosphere layer. [ABSTRACT FROM AUTHOR]

The article provides an analytical review of Russian and foreign sources on the problem of interaction of wind turbines with the surface layers of the atmosphere. The main problems of mathematical modeling of the atmospheric boundary layer in the vicinity of wind farms, associated with difficult meteorological conditions with constant zero crossings in the autumn-winter period, various precipitation, a wide time range, air parameters, terrain and other features have been identified. The analysis of the evolution of mathematical models of turbulence to describe the boundary layer near wind turbines, from earlier to actively developing and currently used. To achieve greater accuracy and naturalism, it is proposed to use high-performance efficient algorithms based on combining scales and physics of phenomena. In the article, the authors proposed a mathematical model for studying the state of the atmospheric polydisperse boundary layer in the conditions of the Ulyanovsk wind farm, considering the presence of dispersed particles in the flow, surface curvature, pressure gradient and other influences. [ABSTRACT FROM AUTHOR]

This article deals with the problem of artificial ventilation of urban intersections. The need to find solutions to this problem is caused by the growth of urban air pollution due to the ever-increasing emissions from industry and transport in the presence of inversions in the atmosphere over the city. As a result of the analysis of existing methods of local influence on weather conditions, a method was chosen to create an upward flow of heated air. A basic design of the meteotron is proposed in the form of a high chimney, for heating which solar heaters are used to create a temperature gradient. Preliminary calculations showed that with a specific power of solar heaters of 250 W/m2, the total power of the meteotron will be 375,000 W, which will create a temperature difference of 4.1 °C. The city meteotron will improve air circulation and reduce the concentration of harmful substances at urban intersections. [ABSTRACT FROM AUTHOR]

This work is devoted to modeling the stationary motion of a conical body in the atmosphere when the bow is heated without taking into account pressure. [ABSTRACT FROM AUTHOR]