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This article describes the design of a compact Wilkinson coupler with an operating frequency of 1000 MHz. This device belongs to the class of power dividers, which are widely used in various microwave systems. The classical design consists of two segments of the transmission line with a length of a quarter of the wavelength, which are connected through the resistance R with a nominal value of 100 Ohms. The presence of resonant segments leads to the fact that the device has large dimensions at low frequencies of th...

Directional couplers implemented on two pairwise identical segments of the transmission line, have only one working bandwidth. In order to organize the performance of the structure on two ranges or more, it is necessary to make design changes to the standard device. For example, for operation at two frequencies, idle plumes are added to the design of the coupler. However, this has further increased the dimensions of the coupler, especially at low frequencies, and in some cases the design may be practically unsuita...

The theoretical analysis is based on the mathematical models of morphological patterns of the thermokarst plains and thermokarst plains with fluvial erosion in case of the ?synchronous start? of the thermokarst processes and little change of climate. The synchronous start means that the initial thermokarst depressions had appeared during a relatively short period and then only their size changed under thermos-abrasion or they disappeared due to their drainage by erosion streams (at the thermokarst plains with fluv...

The strength chart of rocks is an important characteristic in the development of minerals, the design of various geo-engineering structures. In its construction, the strength data of laboratory mechanical experiments are used, which include indirect or direct tensile, uniaxial compression, and triaxial compression according to the Karman's scheme. The necessary minimum information is the data from the first two types of test. Mohr-Coulomb circles are constructed for each specimen in the coordinate system "shear st...

Rapid urbanization encourages the transformation of natural zones into impermeable zones. Because of that, increasing in runoff and decreasing in water quality from urban areas have been appeared. As a solution of these problems, a plenty of technologies related to the stormwater management in urban areas have been developed. The main aim of these technologies is to minimize the environmental degradation. One of the developed solutions is Low Impact Development (LID) technology, which combines measures for polluti...

Investment environment is crucial for countries to attract investors and for economic growth. Baltic States regained independence in early 90-ties, their sizes are comparable and after almost 30 years as independent countries, it is substantial to judge their investment environment and lessons to learn from each other to ensure long-term sustainable development. The paper analyzes and compares investment environment among three Baltic States. The aim of the paper is to determine current investment environment of t...

Currently the problem of surface water quality is relevant and requires urgent solution. There is an intensive growth of rivers? water using those results in deterioration of water quality and hydrological regime. In the conditions of the Mykolaiv region (Ukraine) local water resources are limited. The present situation is aggravated by anthropogenic pollution of surface and groundwater by utilities and agrarian sector. Monitoring surveys of surface water quality are an important tool for environmental assessment ...

Typically, during design stage of a single-family house, only initial costs are taken into account, which are also discussed with the customer and optimized with the aim of reducing them. Long-term calculations are usually not made. At the same time, the calculation of global costs to design, build and operate the building show the real difference in expenses while living in this house. In the case of nZEB building the global cost approach becomes especially useful because of the strict energy demand requirements ...

The energy consumes for district or industrial heating and electrical energy are in most of cases concomitant. The paper analyses from the point of view of the First and Second Laws of Thermodynamics the advantages of producing heat and mechanical power each one individually or through cogeneration. It is clearly pointed out that the energy balance induces the idea that the most efficient conversion process is to produce heat in an individual boiler while the mechanical power production in a steam turbine system i...

Explosive mixtures generated in technological installations by processing, handling and storage are generally complex and in many cases cannot be assimilated with existing specific data. When ignited, they can burn rapidly and result in a considerable explosion force, when in mixture with air in proper proportions. Therefore, for establishing with certainty the requirements of the technical equipment which can be used in potentially explosive atmospheres generated by air / combustible dust mixtures, it is necessar...

The analysis of the actual situation of protected areas and their evolution over time, in an area located on the eastern border of the EU, represents a major interest in identifying national and international policies concerning the estate of conservation and the biodiversity protection. The region aimed to be studied is historical Moldova. It is situated mainly on the territory of two states, Romania (EU member) and Republic of Moldova (former state of the Soviet Union). In time, the historical Moldova existed as...

Both the cultivation of fruit trees and bushes as well as gramineous crops and especially wheat crops are of particular economic importance. Fruit trees and bushes as well as gramineous cereals constitute the most valued foods being indispensable in making a proper diet Research on the study of carabid entomofauna from both ecosistems, wheat and tree fruit plantations was carried out using Barber soil traps. The harvesting of the material was done in both stations between May and August, at intervals ranging from ...

Mining has been for centuries the main economic activity in the Apuseni Mountains of Transylvania, NW of Romania. However, due to the low level of productivity and high production costs, the extractive industry became over the last twenty years one of the large uncompetitive sectors of the Romanian economy. The study area is one where mining activities have impacted both the environment and the social and economic state of the region and it comprises three mining areas located in Alba County: Baia de Aries Mining ...

The aim of the article is studying relationships of soil pressure of forestry machines, determined within different methods. Research methods include computing experiment and calculated data processing. The article analyzes three different methods for calculating the soil pressure, including analytical method for calculating average contact pressure, method for calculating the pressure on a rigid surface, and nominal ground pressure method. Basing on the computing experiment results, the study establishes linear r...

This paper suggests that in order to create efficient backup and recovery strategy for database management system, an appropriate unit of analysis and a proper, data is needed. Key factors for evaluating backup and recovery are time needed to bring the system back online and the amount of data loss. The paper examines methods for managing these factors in three of the most popular DBMS ? MySQL, MS SQL Server and MongoDB. Each of them has a set of backup types that can be combined in different strategies. Depending...

The current article draws a comparison between the 1970 Stereographic projection and the Double-Stereographic projection implemented in ArcGIS under the name ?Stereo 70?. The former map projection is currently being used in Romania for the execution of geodetic, topographic, photogrammetric and cartographic works. It involves formulae with variable coefficients obtained through Taylor serial development in order to convert geographic coordinates into Cartesian coordinates, while the latter projection uses closed-f...

Recirculation aquaculture systems (RAS) are gaining popularity among producers due to high productivity and low ecological impact for the production of aquatic food. Water quality management has always been considered though to be one of the most important aspects of (RAS) systems from both perspectives: ensuring an appropriate environment for fish development and growth and reducing nutrient pollution discharge. In RAS systems, total ammonia nitrogen produced by fish as a result of protein catabolism it is common...

Precise measurement and indication of quantitative concentration of heavy metals in soils is materialized in increased degree of objectivity in research conducted to characterize interactions between pollutants and environmental factors in a given area or region. The present paper aims at highlighting the influence errors induced by physical and chemical characteristics of soils and the fluctuations of soil metal concentrations depending on its humidity and granulometry proposing appropriate methods and techniques...

The leaching of mineral nitrogen (Nmin) represents a serious problem of modern agriculture in the European Union and also in the Czech Republic. The reason is the loss of nutrient important for plants from the soil environment and subsequent threat to the quality of soil ecosystem. The main goal of the present work is to show the influence of the mixed cropping system in the sowing process on Nmin leaching of from arable soil. Mixed cropping system represents cultivation of different crops at one field simultaneou...

The main objective of the article is to compare the current state of professional preparation of crisis management in Slovak and Czech Republic. Various negative phenomena in the life of human society create non-standard crisis situations. Extraordinary crisis situations bring undesirable political instability, social unrest, disruption of information flow and structural arrangements, as well as a number of other threats to the lives of people in the region. Crisis management is aimed at preventing such situations...

Shallow mass movements represent a significant portion within the vast family of landslide phenomena. Moreover, their detection, monitoring and stability analysis is not an easy task. Analytical stability models are often used for the purpose. Their formulation ranges from extremely simple ones to rather complex formulations which include a number of physical parameters intrinsic to the terrain as well as external forcing agents. The application of such models seems to be strictly site-specific as various authors ...

The article is devoted to the study of the effectiveness of various statistical models of the probability of bankruptcy of enterprises based on the examples of the modified Altman model and the model of Sayfulin and Kadykov. A comparison of the results of applying these models showed that in many cases they give opposite results. The reason for the differences is that the Altman model is based on statistics of bankruptcies of American enterprises in 1946-1965, and the model of Saifulin and Kadykov is based on stat...

Birch, primarily silver birch, is used in afforestation of marginal agricultural lands. Natural regeneration on fertile soils most of the cases happens with birch, if no specific management is applied. Therefore share of birch is increasing in hemiboreal forests Previously, target species of forest management had been coniferous trees. Thus the information on the growth and revenue from birch plantations is limited. Moreover, there the minimums density is set to 2000 trees ha-1 in regeneration and 800 trees ha-1 i...

The closure of Neotethys induced collision and extension related basic magmatism within the Central Anatolia during the late Cretaceous and Early Paleogene. The products of the basic magmatism are alkaline and tholeiitic in character. The temporal and spatial evolution of the basic magma within the Central Anatolia has a great role in the interpretation of magmato?tectonic evolution of the region. The lack of radiometric age for the mafic magmatic rocks let to discussion in the explanation of the nature of these m...

Chicken meat is easy to produce, and as a result, it is a cheap and massively used source of animal protein in food. However, poultry farms produce more than 200 thousand tons of chicken manure per year, which must be treated. In the large scale farms biological treatment requires huge facilities and investments, therefore other methods are required. Among them, high-temperature drying and pyrolysis. The goal of this work was to compare the products of chicken manure treatment by means of two thermal methods - hig...

The paper analyzes the impact of marketing tools on market share, sales level and distribution of organic food. The information presented was developed through a literature review and data obtained on the basis of a survey carried out in 40 stores offering organic products, located in Krakow, Poland. As a result, information was obtained from sellers on e.g. the kind of marketing tools used to encourage consumers to buy organic products, their effectiveness, and the decisive factor in favor of the purchase of such...

From 1994 to the present, records of deformations of the Earth?s crust, which are measured by a laser displacement meter, called ?deformograph?, are regularly recorded. This meter records changes in the distance between the mirrors fixed on the rock inside the mountain gallery in two directions: North-South and West-East. Such observations are carried out in the Gorny Altai region, in Kazakhstan and near Lake Baikal. One of the long-acting deformographs is installed in the gallery of the Talaya seismic station in ...

This paper presents the simulation results of field development optimization of low permeability carbonate reservoirs containing high viscous oil by the system of horizontal wells. The wells are located in special way to take into account the geological features of this field, the water injection at certain moments of time and all potential water breakthroughs from the WOC area. Multivariant reservoir simulation runs were performed in order to identify the optimal well density, the optimal length of horizontal sec...

A significant part of the light oil reserves in Russia is concentrated in low-permeable reservoirs, such as the Domanik Formation, Upper Devonian shales in the European part of Russia. Standard laboratory methods for estimating pore space structure and fluid saturation are often not applicable or not accurate in studying unconventional rocks. The presence of hydrocarbons with a high content of highly viscous components, including kerogen, and pores of nanometer size dramatically reduces the effectiveness of the co...

Conveyor belt and especially its cover is viscoelastic material, which means that it combines viscous and elastic properties at the same time. In calculation of motion resistance, mainly in indentation rolling resistance, equivalent lateral stiffness of belts if necessary. To determine this value the distribution of compressive stress (both, in cover and cord) should be analysed. In mine conditions compressive stress in cord disappears gradually and top cover do not take part in cyclical compression. To calculate ...

Enzymatic conversion of lignocellulosic substrates into sugars is an upcoming sphere of biotechnology. Most of the ways, aimed on hydrolysis process improvement are focused at maximizing of raw materials conversion into monosaccharides. Thus, process improvement usually focuses on substrates pretreatment, choosing of the most effective enzyme complexes and control of the hydrolysis process parameters such as increasing the process duration and enzyme dosage, substrate concentration reduction. Kraft woody pulp enzy...

Characteristic features of the petrographic and chemical compositions as well as the age of basic dikes in the Nastenka site of the Malo-Tarynskoe orogenic gold ore deposit (MTD), located in the central part of the Yana-Kolyma metallogenic belt, northeast Russia, are considered. The dikes are composed of light greenish-gray porphyritic rocks replaced by sericite-chlorite-albite-carbonate substance with ore and epidote components, in which relics and fragments of primary igneous minerals are noted. The obtained Rb-...

This paper aims to present a new analytical model for the contact area of all switching devices, at all voltage and current levels. It was proposed in order to recalculate all the computational formulas related to the electrodynamical forces which inevitably appear in a mostly symmetric contact, with a different shape, other than a sharpen or pointed one. When applying this model, the very simplifying hypothesis of the constant current density on equipotential stiction surfaces for the crossing current is complete...

The spectrum of energy resource depletion in the coming years has been a serious alarm signal and has led to the identification of the possibilities for substitution of depleting resources, the reduction of environmental imbalances caused by the exploitation, processing and utilization of the resources used up to now. This alarm signal has led mankind to operate with a new concept, the energy security concept. For most specialists, energy security means producing the necessary energy in their own country and reduc...

There are some relevant problems at prospecting-metallogenic analysis of perspective areas: 1. definition of expected formation (mineral) type of mineralization; 2. estimation of the scale of predicted ore mineralization; 3. outlining of the closest analogue from etalon deposits. During formalization this problems can be determined as the problems of pattern recognition, when objects under study described in heterogeneous property space. The conceptual approach to technology support is following: 1. prospecting es...

Using the open-source library for calculations in the field of kinetics and thermodynamics Cantera, a software module has been developed. Computer simulation of dry reforming of methane in a membrane reactor-contactor has been performed. The one-dimensional mathematical model of gas flow in a porous catalytic coating is used. The influence of a number of parameters, such as characteristics of pores of catalytic membrane coating, and the temperature and the flow rate of the gas mixture on the dry reforming of metha...

Computer technology for Arctic seas water masses analysis is presented. It facilitates data obtained both as remote sensing and in situ. Modern methods and software tools are described as parts of detailed technology in case of one spatial distribution assigned to particular time stamp map and time series of them. Open data from MODIS Aqua satellite project and expeditions listed in World Ocean Database are treated with open source programming tools (R/Python software stacks). Sea surface temperature analysis is c...

The existing approach to data modeling allows to put in an information system only a structure for their factographic mapping. Meanwhile, in reality, data exists within the context which is some user's skill for obtaining them. In the previous study, a model for representing the user's skill was developed. This model represents data in a form of possible action, which, depending on the situation, allows obtaining the expected data. The developed model has such advantages as providing flexibility in accordance with...

At the moment, there is a significant problem of the Russian industry lagging behind world levels. The reason for this is the rupture of connections between social, natural and economic systems, consideration of economics in isolation from the law of nondecreasing growth rates of free energy of living systems. As a result, there was a need for the creation and development of an ?economic system - an industrial enterprise?, i.e. creating a flexible, diversified and receptive to innovation system in order to increas...

The paper is submitted for considering the relationship of geological changes and global economic processes. The authors have confirmed that hazardous geological events are a significant factor in influencing world economic processes. The argument is based on the results of consideration of historical and contemporary facts of world socio-economic development. The historical context of the problem is considered on the basis of a generalization of the historical facts of catastrophic events of geological origin, wh...

The paper reports the results of petrological calculations of some generations of rock-forming (pyroxene, amphibole, biotite) minerals and accessory minerals (zircon and apatite) from the Mesozoic igneous rocks of the poorly studied Dzheltula alkaline massif. It is the largest magmatic structure of the Tyrkanda ore region, located in the eastern part of the Aldan-Stanovoy shield. Obtained results of identification of physical-chemical conditions of pyroxene, amphibole and biotite crystallization indicate the fact,...

Given their wide spectrum of utilizations, the interest for mapping new reserves and prospective areas of useful rocks becomes crucial. On the Romanian territory the natural occurrence of useful rocks is widely spread on the foreland zone, and on the Carpathian structures. These rocks have multiple uses in constructions and various other civil/industrial sectors. Besides being used as raw material in buildings, roads and a variety of miscellaneous engineering works, depending on their petrographic type, these usef...

Geomagnetic data used for the study of the large periodicities of the geomagnetic field are presented as a series of hourly averages covering two solar cycles. These data were downloaded from the ftp site of the World Data Center for Geomagnetism from Kyoto. These data were calculated annually based on final data both from analogue magnetograms and digital recordings. To study the diurnal variations, non-periodic variations (geomagnetic storms, phenomena SSC or SFE) were used as one-minute averages, recorded in Su...

Taking into account that nowadays the websites lacking at least one dynamic component or side is rare (ea. the contact form) the focus of the current paper is granted to the programming environments and the scripting languages used for producing and running dynamic websites. Among the most popular scripting languages the PHP outstands its competitors ASP.NET, Java, CFML or Python. Within this framework, with the aim of separating the content from the presentation of a website content selected aspects linked to the...

A modern feature of websites' creation aside from the PHP scripting language is the use of a database. It is acknowledged that PHP offers the possibility of an advantageous structure for the source code, yet its real capacity is highlighted when the programming language works together with a database. Among these databases one can enumerate MySQL, Oracle or PostgreSQL and the list can be easily extended. The PHP language has predefined functions and native connectivity with the above-mentioned databases. The curre...

Sustainable agriculture appears as a current challenge due to interdependence between the continuous increases of the standard of living correlated with a depletion of the renewable natural resources. Thus, raising the standard of living translates to increasing the population globally and to ensure food is needed access to more and more natural resources and implicitly the phenomenon of wasting part of these natural resources in the form of by-products or by-products. The study also wants to make known as well as...

The coastal lakes of the Romanian Black Sea shore comprise significant ecosystems, characterized by marine, brackish and freshwater assemblages. Therefore, these lakes may be seen as biodiversity huge reservoirs and natural bio-filters. They offer natural resources linked to their high biological production and productivity. This paper is presenting the current research state in the field of quality assessment of the aquatic ecosystems, with special regards to the lakes occurring in the southern Romanian Black Sea...

Wastewater treatment plants produce large quantities of sludge. Sludge originates from different stages of treatment and typically contains elevated levels of heavy metals, a large number of organic compounds and potentially pathogenic organisms. Considering the recent increased environmental concern, the authorities and the water utilities are facing strong demands for the safe disposal of the sludge. A good management plan regarding water treatment residuals should take into consideration the following aspects: ...

In the context of global confrontations in which international energy markets are in a complex transition period, on several dimensions: technological, climate, geopolitical and economic, the energy sector is the biggest challenge and concern, not just at European level, but also globally with profound influences on the competitiveness of the economy, the quality of life and the environment. The current legislative framework in Romania on energy sources encompasses the transposition and implementation of European ...

Nowadays, various climate data sources offer free-access information regarding interpolated climatological data, used in forest research studies (dendroecology and dendroclimatology). The most utilised are the international data grids, for reasons of length of time series and offboard coverage. Changes in the climate extremes from the last decades are frequently monitored using global climate gridded datasets (we used CRU-TS and E-OBS). Our study evaluates their accuracy relative to the national data grid (ROCADA)...