Studies of the Dispersed Composition of Atmospheric Aerosol and Its Relationship with Small Gas Impurities in the Near-Water Layer of Lake Baikal Based on the Results of Ship Measurements in the Summer of 2020

The atmosphere over Lake Baikal covers a vast area (31,500 square meters) and has more significant differences in the composition and variability of gaseous and aerosol components in atmospheric air than in coastal continental areas and is still a poorly studied object. In recent years, the anthropogenic impact on the ecosystem of Lake Baikal has been increasing due to the development of industry in the region, the expansion of tourist infrastructure and recreational areas of the coastal zone of the lake. In addition, one of the significant sources of atmospheric pollution in the Baikal region is the emissions of smoke aerosol and trace gases from forest fires, the number of which is increasing in the region. This article presents the results of experimental studies of the dispersed composition of aerosols and gas impurities, such as ozone, sulfur dioxide, and nitrogen oxides during route ship measurements in the water area of Lake Baikal in the summer of 2020.

Temporal variability of catches, distribution and dynamics of length of Russian sturgeon in waters of the Caspian Sea in 2015 –2020

The paper presents long-term data on catches, distribution and length dynamics of Russian sturgeon in the waters of the Caspian Sea for the summer-autumn periods in 2015-2020. When considering the catches in the different parts of the sea there is found their annual variability, which is especially noticeable in the shallow zone in the North Caspian (0.31-2.0 specimens/trawl) and in the Middle Caspian (0-1.31 specimens/trawl). In the course of determining the reasons for the interannual dynamics of catches there were revealed several decadal rises. The dependence of decadal catches on the temperature of the bottom water layer was analyzed. The highest rise in catches was observed in the first decade of September when the temperature of water lowered up to 20.0-15.0 °C. The increase was observed due to migrating individuals to the shallow zone of the Northern Caspian Sea from shallow waters. Despite the variability of catches, the localization of Russian sturgeon schooling in the northern and middle part of the sea during the summer-autumn periods of 2015-2020 has certain similar features and trends. Sturgeon species fed mainly on shallow banks and deep dumps, where the largest catches of sturgeon were recorded from 5.0 to 12.0 specimens/trawl. The absence of sturgeon at depths of up to 3.0 m isobath in the last five years is due to the water heating up to 27.6-28.8 °C. The decrease in the length of the Russian sturgeon observed in recent years is due to an increase in the proportion of youngsters (19.2-70.0%) against the background of a decrease in the adult population. It should be noted that from 2017 to 2019 there were not found the adult species in the catches by fishing nets, which indicates their continued re-moval from the population.

Crown evolution kinematics of a camellia oil droplet impacting on a liquid layer

The phenomenon of droplet impact on the immiscible liquid is encountered in a variety of scenarios in nature and industrial production. Despite the exhaustive researches, it is not fully clear how the immiscibility of the droplet with impact liquid affects the crown evolution. The present work experimentally investigates the evolution kinematics of crown formed by a normal impact of camellia oil droplet on immiscible water layer. Based on discussion of dynamic impact behaviors for three critical Weber numbers (We), the radius of crown and its average spreading velocity are compared with those of previous theoretical models to discuss their applicability to the immiscible liquid. The evolution kinematics (morphology and velocity) are analyzed by considering the effects of We and layer thickness. Furthermore, the ability of crown expansion in radical and vertical directions is characterized by a velocity ratio. The results show that our experimental crown radius still follows a square-root function of evolution time, which agrees with the theoretical predictions. The dimensionless average spreading velocity decreases with We and follows a power-law, while the dimensionless average rising velocity remains constant. The velocity ratio is shown to be linearly increasing with We, demonstrating that the rising movement in crown evolution gradually enhances with We. These results are helpful for further investigation on the droplet impact on immiscible liquid layer.

Isolation and structure determination of some compounds from the aerial parts of Solanum torvum Swartz. collected in Thua Thien - Hue

Solanum torvum Swartz, belonging to the family Solanaceae, a herb known as “Ca dai hoa trang”, “Ca hoang gai”, “Ca nong”, or “Ca du” in Vietnam, is widely distributed in Vietnam. Solanum torvum has been used as folk medicine to treat various illnesses, such as stomachache, cough, fever, toothache, and bee stings. As a part of our research on genus Solanum in Vietnam, three natural compounds including paniculonin A (1), paniculonin B (2), and isorhamnetin-3-O-glucopyranoside (3) were isolated from the water layer of Solanum torvum collected in Thua Thien - Hue. This is the first time compound 3 was isolated from this species.

Population Status and Habitat Requirement of Endangered Migratory Waterfowl of Patisar Lake, Bahawalpur, Pakistan

Patisar lake is an important wetland for migratory birds in mid-winter which is located in the center of the Lal Suhanra National Park of Bahawalpur, Pakistan. In this study Patisar lake has been explored to find out the endangered bird species. We used a map, a pencil, a notebook, a watch that is used to show seconds and binoculars for the census. Point counting system is used for the monitoring of birds and their habitat requirement was also measured. Result of the study indicated that these population belonging to 6 different orders, 10 different families, 18 genera and 32 different species of waterfowl were observed (1) Podicipediformes iPodicipedidae; iTachybaptus iruficollis), (2) Pelecaniformes (Family: Phalacrocoridae; Phalacrocorax iniger; P. carbo; Family; Anhingidae, Anhinga melanogaster), (3) Ciconiiformes (Family: Ardeidae, Ardea cinerea, A. purpurea, Ardeola grayii, Bubulcus ibis, Egretta alba, E. garzetta, E. intermedia), (4) Anseriformes (Family: Anatidae; Anas acuta, A. crecca, A. platyrhynchos, A. strepera, A. penelope, A. clypeata, Aythya ferina, A. fuligula, A. nyroca), (5) Gruiformes (Family: Rallidae: Fulica atra, Porphyrio porphyrio, Gallinula chloropus) and (6) Charadriiformes (Family: Recurvirostridae, Himantopusi himantopus; Family: Charadridae, Vanellusi indicus, V. vanellus, V. leucurus, Charadrius dubius; Family: Scolopacidae, Tringa tetanus, T. nebularia, Actitis hypoleucus; Family: Laridae,Sterna aurantia). According to They all preferred fresh water layer of the lake and marshes near the lake as their habitat. It was concluded that Patisar lake is a prodigious natural resource for the migratory waterfowl and the number of waterfowl declining with the passage of time.

Effect of the irrigation regime of rise on soil oxidation-reduction status

During the cultivation of rice in the field for 3 months, the required water layer is maintained. In these conditions, there are the processes that lead to changes in the composition of organic and mineral components of the soil, namely: removal of easily soluble substances and mobile forms of nutrients, the dominance of reduction processes over oxidation ones. Irrigation of rice crops using drip irrigation also causes changes in salt and water-air regimes, which leads to the formation of salt bags and toxic salinization of the soil in a layer of 0-60 cm. The negative effect of drip irrigation is not so noticeable compared to flooding conditions and can be eliminated by observing crop rotation with the rate of the main crop not more than 50%. The research was conducted during 2016-2020 in the territory of the Rice Institute of NAAS and its experimental farm (Skadovsk district, Kherson region), where the soil cover is represented by dark chestnut saline soil. The study of the effect of rice cultivation in flood conditions was carried out on a rice irrigation system with an area of ​​190 ha, and under drip irrigation - on a demonstration trail with an area of ​​4 ha. The oxidation-reduction status of the arable soil layer of rice crop rotations when rice growing, is seasonal. In the period of water layer maintaining in the field, in the arable layer reduction processes predominate, while after harvesting and checks draining the intensity of the reduction processes is moderate and decreases. A model describing this process by the equation of a quadratic parabola was constructed. Growing rice under drip irrigation also reduces the oxidation-reduction soil capacity to negative values, but for a short period, which does not adversely affect the soil. The dynamics of this indicator in the conditions of drip irrigation is described by the equation of a quadratic parabola. Continuous monitoring of this process enables to evaluate the stability of fluctuations of the oxidation-reduction soil balance, which is important for assessing soil quality.

Stability of an air–water mixing layer: focus on the confinement effect

The shear instability occurring at the interface between a slow water layer and a fast air stream is a complex phenomenon driven by momentum and viscosity differences across the interface, velocity gradients as well as by injector geometries. Simulating such an instability under experimental conditions is numerically challenging and few studies exist in the literature. This work aims at filling a part of this gap by presenting a study of the convergence between two-dimensional simulations, linear theory and experiments, in regimes where the instability is triggered by the confinement, i.e. finite thicknesses of gas and liquid streams. It is found that very good agreement between the three approaches is obtained. Moreover, using simulations and linear theory, we explore in detail the effects of confinement on the stability of the flow and on the transition between absolute and convective instability regimes, which is shown to depend on the length scale of the confinement as well as on the dynamic pressure ratio. In the absolute regime under study, the interfacial wave frequency is found to be inversely proportional to the smallest injector size (liquid or gas).

Autonomous System for Lake Ice Monitoring

Continuous monitoring of ice cover belongs to the key tasks of modern climate research, providing up-to-date information on climate change in cold regions. While a strong advance in ice monitoring worldwide has been provided by the recent development of remote sensing methods, quantification of seasonal ice cover is impossible without on-site autonomous measurements of the mass and heat budget. In the present study, we propose an autonomous monitoring system for continuous in situ measuring of vertical temperature distribution in the near-ice air, the ice strata and the under-ice water layer for several months with simultaneous records of solar radiation incoming at the lake surface and passing through the snow and ice covers as well as snow and ice thicknesses. The use of modern miniature analog and digital sensors made it possible to make a compact, energy efficient measurement system with high precision and spatial resolution and characterized by easy deployment and transportation. In particular, the high resolution of the ice thickness probe of 0.05 mm allows to resolve the fine-scale processes occurring in low-flow environments, such as freshwater lakes. Several systems were tested in numerous studies in Lake Baikal and demonstrated a high reliability in deriving the ice heat balance components during ice-covered periods.

The Importance of Local Chemistry and Potential in Localized Corrosion and Stress-Corrosion Cracking

The nature and rates of the chemical and electrochemical reactions that occur within the occluded regions of a given alloy are controlled by the local electrochemical potential and the local solution composition. The very small physical dimensions of these regions lead to challenges in both measurement and modeling. When performed in a coordinated and complementary way, measurements and modeling provide insights into the controlling processes of a range of localized corrosion phenomena, including crevice corrosion, pitting, intergranular corrosion, and stress-corrosion cracking. Examples of attempts to overcome the measurement challenges are described for a range of corrosion scenarios, including identification of the critical ionic species in stainless steel crevice corrosion and in the corrosion of aircraft lap joints, operando measurement of chemistry and potential simultaneously within stress-corrosion cracks, and monitoring of water layer thickness in salt spray testing. Examples of work addressing the challenges in modeling localized corrosion including intergranular corrosion of AA5XXX alloys, scaling laws in crevice corrosion, the extent to which the Laplace Equation can be used and applied to geometrically complex galvanic structures, and an approach to modeling localized corrosion for extraordinarily long service times. Finally, suggestions regarding future avenues of research are provided.