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In this study, variations in the paleoecological conditions of Western Siberia were analyzed. For the paleoecological studies, a core of bottom sediments, 51 cm long, was taken from an unnamed lake located in the Yamalo-Nenets Autonomous Okrug. A total of 26 samples from the core were examined in detail. As a result, 30 cladoceran taxa were registered. Among them, Bosmina (Eubosmina) longispina was dominant throughout the core. The subdominant species were Alonella nana and Chydorus cf. sphaericus from the family ...

The aim of the study is to present variation of days with hail precipitation in different regions of Bulgaria and seasonal synoptic classification of such type of extreme events. Examined period is 1991 – 2020. Time-space distributions of days with hail events, detected in at least one station from meteorological network of the National Institute of Meteorology and Hydrology are presented, as well as the regime of wide-spread hail events. The hail precipitation which are detected in at least 4 districts in Bulgari...

The diagnosis of existing structures determines the current state of the selected object. In order to diagnose structures as accurately as possible, it is necessary to choose reliable and effective survey methods, which are used to achieve objective and reliable results. When choosing destructive physical analysis, which includes, for example, concrete cores, accurate and appropriate results are obtained. However, the disadvantage of these methods is that they result in irreversible damage to the structure. For th...

An explanation is given of the regularities of occurrence of constant constituents in long-term series of river runoff, evaporation, and changes in the total water reserves of catchments, which are based on the detection effect, both in hard-deterministic and in stochastic systems – river basins. With regard to long-term runoff, this conclusion is confirmed by empirical data on the probability distributions of almost all the rivers of the globe. For evaporation and changes in the total water reserves, this conclus...

The largest manufactures of glass-ceramics in the last decades are related to the luxurious Japanese tiling material “Neoparies" and its replicas, developed in China. These marble-like materials are produced by sintering and surface crystallization of glass grains (frit) with original composition, placed in large refractory moulds (up to 1-2 m2) and the subsequent grinding and polishing of final panels in use. Since these products are manufactured in high volumes, the technology seems to be very appropriate for sy...

The atmosphere is one of the environmental components, which living organisms utilize the most. However, in large urban agglomerations, the air often contains substances that can be dangerous to human health and ecosystems, especially if their concentrations exceed the legal norms. Although the mechanism of impact of the individual chemical compounds (SO2, NO2, O3, benzene, etc.), considered as pollutants is well known, it is still a challenge to clarify the composition and impact of the particulate matters, espec...

This study aimed to reveal the dependence of the spatial distribution of heavy metals in soil on the morphography of the Lower Danube floodplain in the Ostrovska Lowland in Bulgaria. The field campaign was conducted in 2017, and the concentration of Zn, Ni, Pb and Cr were measured in the fine fraction (<0.063 mm) of 10 soil samples using X-ray fluorescence analysis. The average content of Cr in the topsoil (0-20 cm) was 127 mg/kg ranging between 98 – 171 mg/kg. It was followed by Zn – 81 mg/kg (60 – 128 mg/kg), Ni...

Precipitation chemistry has been intensively studied worldwide mainly due to acid deposition, eutrophication, trace metal deposition, damages to forests and vegetation, ecosystem health, and global climate change [1]. The objective of this study is to investigate the relationship between precipitation pH and wind direction for the period of five years (2015-2019) at coast Hydrometeorology station Ahtopol. The pH of bulk precipitation samples, as well as the wind direction are measured in the main synoptic terms (0...

A mining tailings pond is an engineering construction used for the safe deposition of unexploitable mining waste from mining facilities. This contribution presents a stability analysis of a mining tailings pond. The credibility of the results, when considering the stability of a tailings pond, is conditioned by the aptness of the computing model of the tailings pond, which actually describes not only the constructional arrangement, but also the properties of the geomaterials of the construction of an tailings pond...

Karezes represent a sustainable water supply since their discharge is regulated by the natural groundwater renewal in the mountains and on upslope surfaces in the valleys. Although most karezes have become inactive due to lowered groundwater levels, they can still be used together with other accessible information sources to initially and remotely interpret basin geohydrology and the groundwater resources when they were constructed (and today if still active). This is mainly done by using karezes to map the depth ...

Measurements of high water in rivers are an important element of all collected stream discharge information. It is necessary to have such information in real time during floods because of the danger caused by inundations. Another aspect is the relatively large discharge volume of high water compared to medium and low flow periods. On the other hand, measuring the river discharge during high water with the traditional methods with propeller or floats is often constrained by the manpower availability for that precis...

Peat fires in drained bogs are now becoming more active and large-scale, which poses a great threat to humans and the environment. The projects for secondary watering of drained zones are difficult and require improved methods for their implementation. Space monitoring is the most effective technique to assess the preliminary results and develop recommendations to further projects for the entire area of the bog. Analysis of remote sensing data since 1970 of the southwestern part of drained Orshinsky moss bog in Tv...

Pesticides are intensively used for the protection of field crops, orchards and vineyards, but they are also used in the removal of undesirable stands on non-agricultural land (railway embankments, playgrounds, handling areas, etc.), in water management (in coastal management, destruction of growths in irrigation canals), in forestry, etc. Regular application of pesticides increases their content in the aquatic environment and agricultural products. Their occurrence in water is relatively common and it follows tha...

The development of industrialization worldwide also leads to pollution of ground waters, surface and drinking waters. In order to obtain high quality drinking water, the European Union proposes to develop appropriate methods for purifying water from priority pollutants and potentially hazardous substances. One appropriate method is adsorption, which is a relatively affordable and inexpensive technology for highly efficient water treatment. The aim of the present study is to investigate the adsorption capacity of c...

Global warming is a dangerous phenomenon caused by anthropogenic environmental pollution. Renewable energy sources (RES) contribute to minimizing CO2 emissions. At the 26th meeting of the conference of the Parties (COP26), goals to reduce net emissions were set as soon as possible. At the same time, the European Commission has set the goal of achieving zero net emissions by 2050. Thermal transformation of conventional energy carriers causes the depletion of natural resources, the formation of secondary waste, and ...

This article describes the peculiarities of developing a customizable chat bot. It reviews and compares approaches to developing a chat bot. It describes the features of using Software Development Kit (SDK), which can be easily implemented by a technician into a company's mobile application. Such a chat bot can be used in banks applications, as well as in any other applications which require assistance to the user in solving his/her problem. The chat bot will be able to solve typical user cases, but in more specif...

The blood parameters of rats under repeated inhalation exposure to copper oxide (II) nanoparticles aerosol (CuO NPs) compared to the microdispersed analogue (CuO MPs) have been studied and evaluated. According to the results of the study of the size, specific surface area, and total volume of pores, it was found that the sample under test is a nanomaterial. Rats were exposed to aerosols of aqueous suspensions of CuO NPs and CuO MPs for 10 days at 4 h/day in an inhalation system with a full-body chamber. The actual...

The interiors of buildings are often overheated in summer. The integration of Phase Change Material (PCM) into the building structure can reduce the temperature in the interior because PCMs are able to store latent heat at normal indoor air temperatures. This paper presents the results of the research of mechanical and thermal properties of interior plasters with an increasing proportion of PCM. These plasters were made of gypsum, and microencapsulated PCM Micronal DS 5008 X was used. Two sets of samples with an i...

In this article, we analyze the variability of aboveground dry plant biomass and yield of aboveground phytomass in Trifolium pratense L. and Trifolium repens L. under different growing conditions. The studied species are valuable melliferous, fodder and medicinal plants, which accumulate ascorbic acid, carotenoids, higher fatty acids, glycosides, phenols, flavonoids and other substances. During the growing seasons 2018-2020, we studied 15 natural coenopopulations of T. pratense and T. repens, distributed in the so...

In the Arkhangelsk Region of the Russian Federation, timber industry enterprises in the logistics of transporting round timber use various types of transport: road, rail, water (barges, timber transport units). Large timber processing facilities of the region are mainly located in the city of Arkhangelsk, which is located at the mouth of the Northern Dvina River. In recent years, water transport has been increasingly used to transport raw materials (round timber) from logging sites to processing plants. For the co...

The stone industry is one of the most essential industries in the Alpine region. This research aims to evaluate the possibility of reusing secondary waste materials produced by the quarry sector as aggregates in Ultra-High-Performance Fiber Reinforced Concrete (UHPFRC). The secondary materials involved were Diabase Sand, Diabase Powder, Dolomite Sand and Dolomite Gravel from crushed stone quarries from the regions of Carinthia and Tyrol in Austria, as well as Limestone Powder from the preparation and production of...

In Oituz and Targu Ocna, the attestation of salt extraction was established during the Geto-Dacian period. The oldest written testimony dates from 1380. The mining works that serve the Trotus mine within the Tg. Ocna Salt Mine, are located in the Fetele Targului salt massif located near the town of Tg. Ocna, on the left side of the Trotus river. Currently, the Trotu? Salt Mine has 14 horizons: 2 at the Pilot mine and 12 at the Trotu? mine. The specialized 3D CANVENT program was used to establish the optimal distri...

Usually, only a part of the work capacity is spent in the professional activity, being materialized as products and services made/accomplished within the work process. However, there are also instances, in extreme cases, when total work capacity needs to be engaged, thus an important body reserve being used. Work capacity is represented by the totality of an individual’s (physical, mental, intellectual) possibilities to perform a useful activity at an optimal level of intensity and efficiency. One of the most impo...

The Istria Basin, part of Western Black Sea (WBS) represents a major tectonic unit of the Romanian Black Sea shelf, with prolific hydrocarbon bearing structures. A significant amount of exploration and development wells were drilled on this basin’s northern edge. Core and cuttings data from 12 boreholes provide important details on this basin and the WBS stratigraphy, especially for the two of the main hydrocarbons bearing deposits Upper Cretaceous and, respectively, Eocene, on which we have achieved an age interp...

The separate layer of rhizoid limestone from Urzhumian red succession of Tetyushi Volga region was studied to clarify its depositional features. Field description, optical microscopy, bulk geochemistry, stable isotopes of carbon and oxygen analysis, scanning electron microscopy (SEM) were used. The limestone under study has a thickness of about 1 m, is penetrated by a network of thin root channels (rhizoid limestone), the upper part of the rhizoid limestone is overlain by thin-laminated leafy limestone (3-5 cm) (l...

The depletion of oil fields in traditional production regions leads to the need to involve hard-to-recover reserves in the development. This, in turn, is associated with a significant increase in the cost of production. Well construction costs are subdivided into costs that depend on the time of drilling and costs that depend on the amount drilled. The article indicates that one of the main methods of reducing the cost of drilling is to increase the efficiency of productive time and reduce non-productive time in t...

Risk management is increasingly seen as part of the concept of sustainable corporate development and improvement. It is a logical process or approach that aims to eliminate or at least reduce the level of risk that accompanies the implementation of company policy and achievement of organizational goals. Risk management is part of the managerial responsibility that bears every head of a business or public organization. That is why the issue of optimal risk management policy is particularly important. In this way, t...

The way people perceive risks determines their reactions to and engagement in public campaigns, new development projects or clean-up and remediation initiatives. Since local communities represent important stakeholders in the sustainable development of a region, their beliefs and social representations of risk are important indicators that need a careful analysis. Mining communities are of particular interest to social and environmental scientists given the long-term pollution resulting from such activities and th...

Construction of water-reservoirs across the rivers flowing into the sea often much complicates the coast protection problems. The reason is deficit of filling sediment on the coast-protecting beaches, which settle under the water. Consequently, two problems arise: efficiency of water-reservoir decreases and coastlines start to degrade what eventually ends with coast washing away and disaster. Main goal of is to develop the method of efficient solution of water-reservoir and coastal problems allowing maintaining th...

Natural zeolites having a structure with a large number of cavities allow design lightweight plasters with improved thermal insulation parameters. Focusing on the assessment of plasters’ durability, their resistance to salt damage should to be taken into consideration, especially in case of their application in repair of salt laden masonry. Although the crystallization of salts in plasters presents a serious problem, there is as yet no standard procedure for its evaluation. To predict salt damage of lime-based pla...

The aim of this work is to optimize the growth parameters of D. salina by altering nutritional factors, in order to maximize production of antioxidants and lipid fraction by the microalgae strain. For this purpose, the concentrations of different salts in the growth medium were varied. The biomass obtained was analyzed quantitatively and qualitatively in order to determine biomass concentration and bioactive compounds concentrations in respect to the growth medium composition. Pigments were extracted from the drie...

The rising global average temperature was the main topic at the 26th United Nations Climate Change conference in Glasgow during the climate summit in 2021 (COP26). The meeting aimed to reduce greenhouse gas emissions by 2030 and to discuss the transfer of funds to developing countries. The Europen Green Deal has the same goals. The European Commission aims to achieve climate neutrality by 2050. Climate change has a negative impact on environmental biodiversity, the occurrence of natural disasters, and human health...

Taking into account the sedimentation features since the last 5 decades, considerable anthropic modifications on the Danube channel are present, as the debris composition varies concerning the proportion of terrigenous minerals, lithoclasts, bioclasts and organic matter. Since the 7th decade of the last century, marked by the construction of most hydrological power plants on the Danube, Olt, Jiu, Cerna and other major rivers, a significant change of the sedimentary volume brought downstream by the Danube is assume...

The earthquakes are among the most common natural events in Bulgaria. Earthquakes represent a societal challenge as well as globally necessitating practical and operational solution for mitigating risk and reducing losses. This is achievable though earthquake risk assessment. The assessment of seismic risk is based on procedures for integration of seismic hazard and seismic vulnerability of the bearing structures of the building stock. The building stock is divided into three main groups, taking into account the s...

In oil and gas exploration we need to consider all the geological components and how they come together to have source rock character, trap formation geometry, or reservoir quality. To understand these mechanisms we have to analyze the geological evolution dictated by tectonic uplift, landscape dynamics and drainage network evolution. Paleogeography together with reconstructions of climate and sea level changes allows us to predict source and reservoir facies, which means a great advantage for exploration. The Wes...

An earthquake catalogue covering the seismicity on the territory of Bulgaria and adjacent lands for the period 2000-2020 is presented in the current study. In this catalogue are included events with magnitude equal to or larger than Mw ? 2.5. As a country, Bulgaria belongs to the Alpo-Hymalian seismic belt, it is also not absent of strong earthquakes. Bulgaria is an earthquake prone country taking in account that on its territory are recorded some of the strongest earthquakes from the beginning of the last century...

The problem of studying the interaction of various geophysical (seismic, acoustic, meteorological) fields is considered in the context of prediction of geoecological risks generated by technogenic and natural phenomena. Early it was proved that meteo-dependent processes of infrasound propagation from explosions in the atmosphere can increase many times the ecological load on the social and natural environments. Such situations are observed in the open coalmines, test sites, and other objects where regular explosio...

Protecting the environment is a top priority today. The aim of the paper is to present the possible environmental risks arising from the rail transport of hazardous substances. During transport, new risks of leakage of hazardous substances and environmental contamination from railway tanks arise during their decommissioning at railway stations. These risks can be a significant source of environmental contaminants and there is no methodology to prevent possible impacts. The current situation in Europe has seen some...

The purpose of mathematical modeling of runoff flow in sewer networks is to assess the hydraulic capacity and monitor their behavior in different conditions to predict the future state. Models of sewer networks are part of the design process. Their advantage is the possibility of simulating the future state of the network and the precipitation and runoff process in the context of climate change. With the help of simulations, it is possible to anticipate future conditions in the river basin and thus effectively des...

The article assesses the size of the shadow economy of the Russian oil and gas industry. The article addresses factors in the shadow economy emergence and development in the oil and gas sector. The article justifies methods fighting the phenomenon. The article proposes a system of measures reducing the size of the shadow economy in the oil and gas sector and its impact on the economy of Russia. It has been proven that amid the crisis caused by the COVID-19 pandemic and political and economic sanction pressure of E...

Humanity vision about steadily increasing its quality of life has had as a consequence the maintained search for available odds in order to design various energy supply systems based on different energy resources. The innovative thinking way of human beings has always been also driving the field of shaping more efficient energy supply systems with less unwanted environmental impacts. Conventional energy supply systems, especially based on fossil fuels, have been since long applied, their impacts being especially p...

Urban floods, which are most often caused by intensive rainfall and the fast formation of surface runoff, cause great damage to the urban population and infrastructure. Due to the stochastic (random) nature of precipitation, it is not entirely possible to achieve reliable operation of sewer systems. We can only try to design and operate them in the most reliable way. Urbanization and changes in climatic conditions are one of the main factors for increasing the frequency of flash and rain floods in urban conditions...

The materials used for the synthesis are modified waste raw materials in the form of slags (up to 70 % wt.) with addition of quartz sand and calcium fluoride. The initial batch is being melted at 1400 oC and then quenched in water. The resulting glass frit is milled bellow 75 microns, pressed into “green” samples being exposed in a next stage to thermal scanning at different temperatures with different heating rates, holding temperatures and times. In the framework of present investigation is presented analysis of...

A severe problem affecting urban areas is a large number of stray animals, either r eject- ed by their owners or born in the wild. These animals face the problem of malnutrition, as it is difficult for them to obtain food without human help in urban conditions. The fact that shelters are overcrowded is not suitable for these animals as well well. In o rder to protect them from the tragic death of starvation, the authors decided to de- velop an intelligent system for feeding stray animals. The system makes it possi...

The forests of south-western part of Zemgale Plain in Latvia are characterized by Scots pine (Pinus sylvestris L.) stands on fertile, nutrient rich soils. The existing information about these sites suggests of the calcium carbonate rich loamy sand soils formed by moraine. The Scots pine stands in area of Tervete National Park reach age of 260 years. The oldest and biggest trees reach considerable dimensions – up to 70 cm in diameter and height of 47 m, thus exceeding the country's average indices. These are the ol...

The processes of liquefaction of water-saturated soils under dynamic impacts are one of the many negative and destructive geological processes and phenomena that constitute the geological hazard in Bulgaria. Processes of liquefaction of water-saturated sediments on the territory of Bulgaria are registered during almost all strong earthquakes affecting its territory from both local and regional sources. Specific cases have been described by a number of authors. These processes lead to loss of bearing capacity of wa...

Soil water content and understanding water dynamics is crucial for agricultural practice. Direct measurements of the soil moisture are being slowly replaced by the mathematical simulations and models. One of the most used models for the simulation of the soil moisture is the HYDRUS 1D model, which simulates how the water is transported through or within the soil profile. The soil water model HYDRUS can simulate water movement through a porous media during transient (irrigation) and steady state (between irrigation...

Unfortunately, soil is a non-renewable resource that fulfills several vital functions such as food/biomass production, storage, filtration and transformation of mineral or biological substances, source of biodiversity and habitats, etc. Due to the development of industrial activities outside the localities, in many areas the soil is degraded. Among these degradation processes can be mentioned degradation of organic matter, contamination, soli salting, and erosion. This paper is dedicated to the presentation of the...

The studies of the medieval fortified settlement Kushmanskoe-3 showed significant differences in the chemical properties and biological activity of the cultural layers of plots located on the inner and outer parts of the settlement, on both sides of the fortification line. The average values of organic carbon, total phosphorus, urease activity and the number of thermophilic bacteria were significantly higher in the cultural layers on the inner plots located to the south of the fortifications, as compared to the cu...

Decision-making theory has been developing significantly for the last 50 years. It finds its various applications in the very different fields of human activities: engineering, social and life science, and sure economics. The task of substantiating decisions under conditions of uncertainty of all types, except for a priori is reduced to narrowing the initial set of alternatives based on the information available to the decision maker. The quality of recommendations for decision-making under conditions of stochasti...