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The Ogosta Valley downstream the town of Chiprovtsi, NW Bulgaria, was subject to long-lasting contamination with arsenic and other toxic elements due to mining and ore-processing activities in the second half of the last century. Although the exploitation of lead-silver and iron ores was ceased in the end of the 90`s, the soil in particular sections of the Ogosta?s river floodplain remained highly contaminated with arsenic, lead and other heavy metals. Arsenic mobilization and transport in the vadose zone is highl...

Machine learning covers a wide set of supervised and unsupervised algorithms for solving prediction, classification and anomaly detection problems. One of the areas of their applications is for customer churn prediction. To build a model for predicting the switching of customers, data scientists use different demographics, social, transactional, behavioural metrics and features. At the same time, most of the small Bulgarian companies still don?t have the needed versatile and complete customer data. They rely mainl...

Earthen levees are commonly used protective structures against seasonal flood activity. Monitoring of the embankments condition is an important issue related to the protection of people's lives, their property, environment and infrastructure. The assessment of the physical condition of the levee can be obtained by comparison of the sensors measurements? localized within the embankment and the changes in parameters values obtained as a result of numerical modelling of flooding process. Uncertainty of the values of ...

Medical materials based on natural polysaccharides can be used as hemostatic sorbents and dressings. In this work, some samples of sponges had been obtained based on sodium alginate and chitosan. The concentration of sodium alginate in the solution, the ratio of alginate and chitosan were varied during an experiment. Polysaccharide cross-linking was carried out by inotropic gelation or by combining ionotropic gelation with ionic substitution. According to the literature, a chitosan have antibacterial properties ag...

Medical materials based on natural polysaccharides can be used as hemostatic sorbents and dressings. In this work, some samples of sponges had been obtained based on sodium alginate and chitosan. The concentration of sodium alginate in the solution, the ratio of alginate and chitosan were varied during an experiment. Polysaccharide cross-linking was carried out by inotropic gelation or by combining ionotropic gelation with ionic substitution. According to the literature, a chitosan have antibacterial properties ag...

Methods of parasite structures visualization using fluorescent probes are widely used in nowadays. The technological utilization of benzanthrone dyes is growing, but in biology studies they are still rarely used. Our studies show the advisability/expediency of using these dyes in investigation of helminthes structures. The aim of present study was to evaluate the novel synthesized luminophore AZP5 for efficient staining of trematodes for confocal laser scanning microscopy. All helminthes were previously preserved ...

Methods of parasite structures visualization using fluorescent probes are widely used in nowadays. The technological utilization of benzanthrone dyes is growing, but in biology studies they are still rarely used. Our studies show the advisability/expediency of using these dyes in investigation of helminthes structures. The aim of present study was to evaluate the novel synthesized luminophore AZP5 for efficient staining of trematodes for confocal laser scanning microscopy. All helminthes were previously preserved ...

Testing of synthesized magnetically separable catalyst (Pd-Fe3O4/HPS) was carried out in the selective hydrogenation of 2-methyl-3-butyn-2-ol to corresponding olefinic alcohol and also in the Suzuki cross-coupling of 4-bromoanisole and phenylboronic acid in a shaker-type glass batch reactor. In the case of selective hydrogenation, the use of Pd-Fe3O4/HPS was found to result in 94% selectivity at 95% of the substrate conversion that is typical for preliminarily reduced Pd/HPS catalysts. Regarding to the Suzuki reac...

In the zones of boreholes drilled to explore and extract hydrocarbons uncontrolled migration of gas to soil environment and therefore to atmosphere may occur. Such phenomena may be related to insufficient tightness of the rock mass or poor technical condition of the borehole. Due to the occurrence of potential risks to the environment and human health and life, a set of constant monitoring probes was designed and tested. Location of six permanent monitoring probes were based on the results of surface geochemical s...

The customer expects the quality and reliability of purchased devices. Every defect on the device causes loss of brand confidence and customer dissatisfaction. Customer satisfaction is, however, the best indicator of how likely customers will continue to buy in the future. If an organization wants to maintain a customer, it must be customer-oriented. The company has decided to improve the quality and reliability of its products. This can also help to increase the number of satisfied customers and gain competitive ...

The article presents practical problems related to the application of REACH and LCA standards in the construction sector. Chemicals are an essential factor in assessing and managing of all kinds of risk due to their importance as components of materials and their various effects, such as: adverse and beneficial, biophysical and socio-economic. The process of reducing of adverse environmental impact of construction sector on the environment is a subject of increasing attention of scientists and companies. It should...

Aqueous-dispersion acrylate compositions with different contents of silica nanoparticles (NP) were prepared, which allowed to obtain top transparent coatings with improved abrasion resistance. The nanoscale silica used in the work was obtained by a gas-phase method using high-frequency induction discharge (HFI) in the air atmosphere. The average size of silica nanoparticles measured by transmission electron microscopy (TEM) and laser scattering was 23.5 nm. TEM photos of silica nanoparticles showed that silica was...

Sources that contain data about tourism in Bulgaria are both structured and unstructured. Information from these xls and pdf files is organised in a created relational database. The database stores time series on tourism flow (trips of Bulgarian residents abroad and foreign tourists to Bulgaria), expenditure of outbound tourists, revenues from international tourism and employment in tourism. This article studies time series on trips of Bulgarian residents abroad (outbound tourists) by country of destination and by...

With the steady rise of interest in blockchain and related technologies, researchers are making efforts to solve the remaining open questions in this field. One of the open problems is to achieve and maintain some desired characteristics of a private blockchain as far as the block generation rate is concerned. This problem is routed in statistical modeling. In this work, we will apply the results of participatory computing to build private blockchains and to resolve this issue. Private blockchains are important in...

The method of accelerometric control of transport streams, which is part of the system of geotechnical monitoring, is considered. The main features of accelerometer sensors application in solving the identification problem of parameters of the transport stream are described. A mathematical model of the vibration load on local sections of the road is described. It is proposed to evaluate the effect of the transport load on the basis of the recorded parameters of the propagation of vibration effects arising from the...

Porosity belongs to basic characteristics of building materials. It is a characteristic of solid or semi-rigid materials, which contain a lot of tiny and uniformly distributed cavities or holes of various shape and origin. Porosity decreases specific weight of materials, increases their insulation and other characteristics ? for example absorbability. It is defined as a ratio of pores volume in a specific amount of solid and the total volume of this amount. In the article the use of the modern confocal scanning mi...

Modelling is the process of replacing the dynamic system of its model. The loading of mineral resources is an integral part of their circulation. The first loading process is being carried out during the excavation of raw materials. Subsequently, the loading process is carried out in the other stages of its transportation by various means of transport or processing. The contribution describes a model example of loading the selected mineral raw material into the selected type of transport means railway wagon. The m...

The aerial survey results have shown a number of benefits of aerial survey if compared to ground survey. Unmanned aerial vehicle can be effectively used in surveying works in opencasts. At the same time, this technology allows to improve accuracy, safety and effectiveness of surveying works as well as reduce costs and labor effort. The surveying department and industrial engineers of JSC SUEK for surveying works in open pits have applied the unmanned aerial vehicles. As the result, labor productivity increased sig...

We focused at the presented study at the valorization of biomass ash as filler in the design and development of new eco-efficient alkali-activated geopolymers. Since coal fly ash is one of the main precursors used for alkali-activated geopolymer production, this research examines the use of biomass ash, which can have comparable chemical composition and physical properties to coal fly ash, and thus can be potentially geopolymerized in the same way. In this study, the wheat straw ash is used together with diatomace...

With introduction of new and advanced technologies in beekeeping it is possible to design and use Internet of Things (IoT) sensor systems embedded in beehives. This provides the ability to collect heterogeneous data and to provide real-time remote monitoring. Complex prognostic models are applied after the data is manipulated and normalized. The obtained results are used to predict the processes occurring in beehives. For this purpose, the collected data must be divided into at least two parts for training and val...

With introduction of new and advanced technologies in beekeeping it is possible to design and use Internet of Things (IoT) sensor systems embedded in beehives. This provides the ability to collect heterogeneous data and to provide real-time remote monitoring. Complex prognostic models are applied after the data is manipulated and normalized. The obtained results are used to predict the processes occurring in beehives. For this purpose, the collected data must be divided into at least two parts for training and val...

The paper deals with the application of the pulse tomography Arbotom as a support decision tool for management of hardwood floodplain forest in the Czech Republic. The method of acoustic wood tomography is based on the finding that intact wood conducts sound faster than damaged wood with defects. Tomograph measures the time which takes a mechanical pulse (an acoustic wave) to pass the distance between sensors placed on the tree trunk. The evaluation of the trunk measurements in two-dimensional tomograms then shows...

Changing the shoreline is an element of great interest for the coastal communities. The multitude of social, economic and environmental activities that take place in the Romanian coastal area requires a strategic approach. In the present paper, we are discussing strategic options for human intervention in the Romanian coastal zone. Engineering works to protect coasts from coastal erosion must be closely linked to human activities that take place in the coastal area, even though we are talking about tourism, transp...

One of the most common problems reported in the mature oil-producing regions of the world, i.e. related to the fields that are in a state of declining production or reaching the end of their productive lives, is associated with organic deposits forming both in and around the wellbore. Paraffin, resin and asphaltene deposit (ARPD) has been a problem for operators in many areas since the beginning of petroleum production from wells. There is a variety of techniques and means to control these deposits, and the most p...

The approximation of Kosovo legislation with the European Union (EU) acquis for the European integration process, is a complex one. Its complexity can significantly differ from filed to field. Moreover, the constant and rapid development of European environmental law makes this process even more challenging and demanding for Kosovo institutions. The aim of this paper is to provide a general analysis of Kosovo environmental legislation in the light of its approximation with EU acquis by using mainly the comparative...

Mostly significant regional problem related to fluctuations of the Caspian Sea level was considered. Despite the diversity and abundance of approaches to forecast sea level, the question still remains open. Adapting the method of stochastic modeling has allowed to predict the level of change in the next term of the fiftieth anniversary.

The design of a social housing complex that is accessible to all population groups including disabled people, elderly people and families with children can be achieved only with application of architectural and gerontological principles. The gerontological direction in designing is connected with a comprehensive account of the dynamic changes in a person's life, his physiological and social characteristics, changing during the life of the population's needs for the organization of living space. The paper confirms ...

This study presents the investigations above the massive masonry elements in order to analyze the long term behavior for the patrimony buildings subjected to the environmental factors and the strong seismic movements occurring during their lifetime. Although the patrimony buildings was structural rehabilitated after the major earthquakes occurred during its lifetime, the cracks in foundations were neglected. One of the causes of degradation is the capillarity of the soil water through these cracks. Excess water ac...

Further development of digital economy requires researching the limits of some algorithms applicability. These algorithms are based on the mechanisms obtained as a result of investigating the processes of ?alive? nature. Such algorithms were called the bio-inspired algorithms and are widely used in practice, for example, for solving the problems of multi-agent systems coordinated control. Application of coordinate descent, a type of gradient method ? extends the description of the existing shepherd dog algorithm. ...

The article considers modern operating systems for increasing energy efficiency at the municipal and regional levels. Present successfully applied practices in other regions are given. The essential distinctive features of the proposed system for the Belgorod region are revealed. Described, developed methods and algorithms for managing energy con-servation in the budget sector. The structure of complex interaction of the developed modules used in the created software component is offered. The regional and municipa...

The safety of hydrotechnical structures is a very important element that must enter the concerns of designers and society in general, given the fact that these are important works , with large investments. In the case of their distruction due to accidents, other activities from the area, the settlements and human lives may be strongly affected. These accidents are called hydrological hazards. [9] Breaking earth dams accidents do not occur suddenly but almost always there are signs of danger that would allow prelim...

Cement is a silicone-based hydraulic binder, obtained by fine grinding of its components: clinker, limestone, gypsum, blast furnace slag, possibly grinding additives, but also other components such as kiln dust (CKD). The clinker is the most important component of cement, which is a granular material obtained by burning a powdery mixture of limestone and clay, with possible correction additives, in a furnace at 1450oC. The milling of clinker and other cement components is accomplished by means of ball mills with t...

Evaluation of explosion-proof protected electrical equipment in scope of certification is extremely important considering the risk of explosion that has to be minimized in order to ensure life safety and health of workers and to prevent damaging of property and the environment, as well as free movement of goods when they meet the essential safety requirements at European level. The purpose of this paper is to present aspects regarding the importance of thermal endurance tests performed on the electrical equipment ...

The documents of the general cadastre may result from the centralized and selective take over of the data and all the cadastral records from the specialized cadastre, regarding the immovable assets that are their object of activity. These selectively taken elements use to update the general cadastre after the end of its introduction into an administrative territory. One of the main steps for completing the general cadastre is the realization of the real estate cadastre. This article presents the way in which the d...

The paper presents a study on water quality, which can be influenced by biological, physical and chemical parameters of water. Water quality has the purpose of identifying the direction of water use for both domestic and industrial purposes and is of particular importance to humans and living organisms. In addition to the human factors that have a major impact on water quality (both for surface and for groundwater), there are also natural factors and anthropogenic activities. The purpose of the study is to analyze...

Building is constantly heading for the development of new technologies, better materials and reduction of energy consumption, however daylighting remains an essential factor that considerably affects the interior of buildings and it cannot be technologically improved or replaced. The total quality of the indoor environment is crucial to humans. Daylight is important not only from a psychological and health point of view, but also from the point of health standards. People who are forced to work in workplaces witho...

Major infrastructure projects are nowadays benefiting on the remarkable IT structures which allows to use large datasets of the geotechnical parameters of interest and therefore to test different technical solutions, adapted to the site geology and local tectonic setting. Therefore is of major interest to have an improved knowledge upon the hazardous geological features, to evaluate them and to select among the possible technical solutions the most advantageous (in term of stability, strength and costs). In this s...

The research carried out in the present paper aimed at monitoring and evaluating the technological process of obtaining the ecological cheese type ?PETROVA?, in the Maramures county area, Romania. To achieve this raw milk originating from domestic producers was evaluated in terms of fat content, acidity and density of this. After the final ecological cheese type product has been obtained, analyzes have been made for it?s physicochemical evaluation as follows: water content analysis, fat content analysis, salt cont...

The research carried out in the present paper aimed at monitoring and evaluating the technological process of obtaining the ecological cheese type ?PETROVA?, in the Maramures county area, Romania. To achieve this raw milk originating from domestic producers was evaluated in terms of fat content, acidity and density of this. After the final ecological cheese type product has been obtained, analyzes have been made for it?s physicochemical evaluation as follows: water content analysis, fat content analysis, salt cont...

The research carried out in this paper aimed to evaluate five types of beer throughout the technological flow of their production. The technological flow of producing the five types of beer has been monitored at all stages of it, starting with beer must, beer before filtering, BBT beer and bottled beer. To achieve this goal, the following physicochemical analyzes were carried out: color analysis expressed in EBC units, pH analysis, determination of bitter substances expressed in units of B.U. All the results obtai...

The research carried out in this paper aimed to evaluate five types of beer throughout the technological flow of their production. The technological flow of producing the five types of beer has been monitored at all stages of it, starting with beer must, beer before filtering, BBT beer and bottled beer. To achieve this goal, the following physicochemical analyzes were carried out: color analysis expressed in EBC units, pH analysis, determination of bitter substances expressed in units of B.U. All the results obtai...

This paper presents the first year of the field experiment to evaluate the possibility of growing corn (Zea mays ssp. mays) in mixed culture (MC) with selected leguminous species. The main objective was to monitor the influence of MC agrotechnology on the yield of maize, individual leguminous crops and evaluation of biological yields through using the Land Equivalent Ratio (LER) for each variant of experiment. The selected legumes plant and corn were grown separately like sole crop (SC) or in MC (legumes and plant...

Underground hard coal exploitation leads to the formation of granular porous media. These media occur both in the underground parts of mines and on the surface. In the underground areas, these are the caving goaves of longwalls and the caved-in roof rocks in active mine headings. On the surface, these are most commonly the post-mining waste dumps. In both of these cases, a crucial role is played by the knowledge on the resistance of air and gases flowing through these media. In the case of underground exploitation...

Mapping, assessment, protection and their introduction in thematic circuits are steps which, once completed, will turn the geomorphosites near Topli?a resort into benefits for tourism. Methodology consists in field research, inventorying and evaluating various geomorphosites, based on scientific and cultural values. Topli?a resort developed in the volcanic area of the Eastern Carpathians, at the entrance in Topli?a?Deda defile, underneath the volcanic calderas of the C?liman Mountains and the Northern Gurghiu Moun...

Lichens are widely used in studies of identification of various types of natural and anthropogenic pollution. As for mosses, they accumulate heavy metals and rare-earth elements. It makes them applicable for studies of a territory with long-term man-made pollution of the atmosphere. To evaluate the atmospheric air pollution in Tomsk and Prokopyevsk (Russia, Siberian region), the following two comparative analyzes were made in this work. Firstly, the elemental compositions of ash residues of epiphytic mosses and li...

Atmospheric boundary layer (ABL) dispersion conditions relate to key natural factors that characterize radiation and environmental safety of nuclear power plants (NPPs). Therefore, the said conditions are studied in sufficient detail even at pre-design stages of NPPs construction. Given the ongoing development of nuclear power industry, synthesis of methodological approaches to NPP siting options with due account of atmospheric dispersion conditions is of great interest. Formal pursuit of requirements and recommen...

In Romania, most agricultural farms are subsistence farms and have to face two major problems: lack of capital and impossibility to sell their own production on the market. In the farm production costs, a significant share is represented by the fuel costs (Diesel oil); that is why the authors of this paper evaluated the possibility to lower the costs on the agricultural farms by producing biofuels for the farm own needs. The research work took place at the Banat University of Agricultural Sciences and Veterinary M...

Article represents the calculation of the long-term average annual soil loss using the universal soil loss equation (USLE) in the model river basin. Soil loss will be assessed with respect to land use (in the categories: arable land, vineyard, garden, orchard and permanent grassland) and slope (in the categories: less than 12В°, 12В° ? 20В° and more than 20В°). There is a Slovak technical norm: Hydromelioration ? Erosion control protection of agricultural land. Based on this norm land users must comply with the de...

The purpose of creating National Parks is to restore the proper state of nature in a given area. An attempt to recreate distorted landscape values is a long, arduous and expensive process. Part of the Parks? operating costs is covered from admission fees for tourists to enter their areas. However, to prevent negative impacts of visitors on the natural environment, visiting National Parks is subject to particular restrictions. Tourist traffic is carried out only according to specific rules resulting from legal prov...

Ecological state of the Lower Section of the Dnieper River was estimated by method of calculation of integrated index on the basis of monitoring over the years 2013?2016. Self-purification potential and capability of restoration in time and space (along the river stream) of the aquatic ecosystem of the lower section of the Dnieper River was established. The method for assessing the quality of surface water by hydrochemical parameters in accordance with the fishery standards as the most sensitive to changes of the ...