Corrosion Behavior of Spherical Chromium Carbide Reinforced NiCrBSi Hardmetal Coatings in Sulphuric Acid Solution

In the present work, four groups of spherical chromium carbide reinforced NiCrBSi hardmetal coatings were prepared on AISI 4145 steel by plasma transferred arc (PTA) technique. The corrosion behavior of the four as-received hardmetal coatings in 0.5 mol/L H2SO4 solution was investigated by polarization curve and electrochemical impedance spectroscopy (EIS). The results revealed that more Cr-rich carbides (Cr3C2, Cr7C3 and M23(C, B)6) are formed in the chromium carbide reinforced coatings, while for the NiCrBSi hardmetal coating only Cr7C3 carbide was detected by XRD. The polarization results show that the chromium carbide reinforced NiCrBSi hardmetal coatings have positive corrosion potential and lower corrosion current, providing a better protective effect to the substrate metal. The combined effects of Cr-rich carbide ceramic phases and a more stable passive film of Cr2O3 greatly improved the corrosion resistances of the chromium carbide reinforced NiCrBSi hardmetal coatings. The coating with the highest spherical chromium carbide addition has more pores because of the thermal stress due to the difference of thermal expansion coefficient between the NiCrBSi bonding phase and chromium carbide reinforced phase. The negative effects of the pores weaken the corrosion resistance, and the coating with the 30% chromium carbide content shows the best corrosion resistance. For NiCrBSi hardmetal coatings with higher reinforced chromium carbide content, the repeatability of the corrosion current obtained by polarization fitting is not as good as that of coatings with lower chromium carbide content. The repeatability of polarization results becomes worse when the specimens keep in a more stable passive state.

Johann Georg Zimmermann’s Therapeutics of Solitude in the German Enlightenment

This essay charts the German eighteenth-century physician and writer Johann Georg Zimmermann’s monumental work on solitude. The essay draws on but also challenges recent historiography on two counts. First, it situates Zimmermann’s discourse on solitude in the context of the early modern cultura animi tradition, in which philosophy provided a cure for a soul perceived as diseased and perturbed by passion and desire. Placed in this context, solitude comes into view not primarily as a passive state of rest and tranquillity connected to the rural life, but as active, therapeutic and exercise-oriented work on the self. Second, it argues that Zimmermann also shaped his discourse in relation to the increasingly radical late eighteenth-century exploration of subjectivity and selfhood, an exploration that reflects the emergence of the modern conception of the unique individual and autonomous self.

MIGRATION MOBILITY OF THE CARPATHIAN REGION YOUTH: PROPOSITION OF IMPROVEMENT OF INFORMATION -ANALYTIC SUPPORT OF REGIONAL MIGRATION POLICY

The development of the new information-driven society along with the penetration of the globalization processes in all social and economic activities became the entities of the liberalization of the migration relations, which simplify in general the youth moving and increase its mobility. Based on statistics and administrative data analysis about youth migration from Carpathian Region it was determined that quick spreading of the positive migration aspirations among the youthful population gets new looms and can lead to the migration deprivation ramp-ups in the Carpathian Region in the future. Mainstreaming of the external migration climate and escalation of the problem are also heavily mandated by the entity of the passive state and regional migration policy, which manifests through immature system of the real complex migration registration, unfinished state of system of the institutional-organizational and institutional-legal regulation of the migration processes at the regional and local levels, low quality and low organizational and technical options of the migration services’ infrastructure elements, insufficient use of the resources of the migration exchange programs in the field of education, science, innovation and research activities, tourism, investment and business projects, the lack of regional programs of the stimulation of the educational and labor migrants’ re-emigration. In the attempt to eliminate gaps in migration policy and minimize the risks and threats of the growth of migration activity of the Carpathian Region youth, the instruments and methods of external migration monitoring system’s improvement, the development of the regional databases of migration structural-dynamic characteristics, the development of migration policy preventive instruments aimed to regulation of the regional labor markets, and the corresponding implementation of the migration services market infrastructure’s development, stimulation of the educational and labor migrants’ re-emigration, improvement of the migration policy institutional support in the Carpathian Region were proposed.

Marketing analysis of demand and supply in the labor market of Ukraine

The labor market is a complex socio-economic phenomenon that requires constant monitoring and regulation. There are a significant number of definitions of this concept, which are significantly different and quite harmoniously complement each other. At the same time, scientists use complex, systemic and dialectical approaches. Scientists consider typical models of the labor market: American, Japanese, Swedish and Chinese, which differ in a number of key features and principles of operation. The labor market in the process of formation and functioning performs a number of functions: social division of labor; informational; mediational; professional counseling; regulatory; pricing; proportionality of the distribution of labor in accordance with the structure of social needs and the development of scientific and technological progress; reserve. Herewith, as a separate element of a market economy, it interacts with markets: capital, raw materials, information, educational and scientific services, health care, cultural and spiritual services, household and social services, housing, innovation, etc. The demand and supply of labor, its cost and price are the main elements of the labor market. Labor exists in the labor market as a specific commodity, which is characterized by a number of features different from other products of a market economy. In the process of buying and selling labor, a number of relations arise between the subjects of the labor market, which constitute a certain system. The ratio of supply and demand of labor, in other words conjuncture of market, are formed under the influence of internal and external factors of the labor market, as well as the level of employment and unemployment. There are three types of conjuncture of labor market: equilibrium, redundant labor and insufficient labor. Labor market conditions are changing due to the natural and mechanical movement of labor and jobs. In Ukraine, the labor market situation is characterized by structural disparities between labor supply and demand, which have become a chronic problem of the national economy. PEST-analysis as a marketing tool should be used to determine the importance of the influence of various factors on the formation conjuncture of labor market. It includes political, legal, economic, socio-cultural and technological factors of the external environment. Market instruments and partly means of active and passive state policy of employment regulation should be used to regulate the labor market. The main regulators will be to remain: the country's legislation, economic laws, the trade union movement and the media, national traditions, mentality, climatic and historical conditions of the country.

COATING FOR PROTECTION OF CONCRETE FROM SULFATES

Durability of reinforced concrete is one of the main demands in civil engineering.Operating conditions, particularly in aggressive mediums, determine durability of constructions.Sulfate mediums are among the most aggressive ones which cause steel reinforcement corrosion. Themodern requirements for high consistency fresh concretes are governed by practice. This way thedisturbance of reinforcement passive state can be caused by changes in hardened concrete especiallyin aggressive mediums. Thus, the restriction of SO42- ions transport in concretes, which are obtainedfrom high consistency fresh mixes and exploited in sulfate mediums, can be considered as an actualproblem.The paper is devoted to protection of concrete surface by coating based on alkali-activatedaluminosilicate binder from SO42- ions transport to prevent steel reinforcement corrosion. It wasshown that the coating with thickness of 3 mm ensures total concrete protection. It was revealed thatpermeability of concrete depending on cation decreases in the row (NH4)2SO4>Na2SO4>MgSO4. Theprotective function of coating was simulated by application of mentioned salts as admixtures. LesspH values of water extracts of the binder during hydration while using of 2.5 % MgSO4 is evidenceof advanced crystallinity of zeolite-like sulfate-containing hydroaluminosilicates with participationof Mg2+ ions equal to Са2+ ions. While content of (NH4)2SO4 was increased up to 5.0 % less pH wasfixed due to decelerated formation of zeolite-like minerals. Stability of pH values in presence ofNa2SO4 (0.5…2.5 %) was caused by no influence on structure formation. Thus, the restriction of SO 2-ions transport in protective coating is due to their binding by alkaline aluminosilicate binder inzeolite-like minerals with higher crystallinity due to presence of Na+, NH + and Mg2+ cations fromsulfates.

Das Zustandsreflexiv im Vergleich zum Zustandspassiv nach mantischen und syntaktischen Kriterien eine theoretische und konfrontative Studie

The present study deals with two vital linguistic phenomena, namely the state reflexive and the state passive in contemporary German. These linguistic phenomena are treated not only according to semantic, but also according to syntactic criteria. The state reflexive and the state passive play an important role in today's linguistic usage, so that they should be given special attention and interest as linguistic phenomena. The use of the state reflexive and the state passive gives the speaker or writer a means of avoiding superfluous language elements in the sentence. The present work tries to show the difference between the reflexive state and the passive state, since the Iraqi students as well as the German-learning Arabs have great difficulties in using these two grammatical phenomena.

Study, improvement and evaluation of electro-corrosion resistance of highly effective inhibitory compositions

The studies on the improvement of boron nitrogen-containing compounds, as well as information on phase transformations in the system H3BO3-C3H4N2-H2O, based on the solubility isotherms consisting of three branches, are presented. Based on the analysis of the second branch, a new boratimidazole compound was found. A full description of its properties is given. Furthermore, the paper presents the studies on the effect of boratimidazole and emidazole on the corrosive electrolytic behavior and the main characteristics of the cyclic strength of pre-eutectoid carbon steel in neutral media. It is found that the introduction of emidazole and boratimidazole into corrosive media reduces the ionization rate of steel, reduces the density of the anode current in the passive state region and increases the main characteristics of the cyclic strength of the metal. It has been shown that emidazole has a lower inhibitory ability than boratimidazole. The obtained experimental results of gravimetric studies, electrochemical changes and corrosion-fatigue tests are in good agreement with each other and with the previously obtained data. Boratimidazole is a quite effective corrosion inhibitor and can be used to protect ferrous metals and their alloys. The development of new effective, environmentally friendly corrosion inhibitors based on boron-containing compounds is an important scientific and technical task. To develop new compositions of anticorrosive reagents, the method of physical and chemical analysis, which is the scientific basis of modern materials science, is used in this work.

An Evidential Approach for Area Coverage in Mobile Wireless Sensor Networks

The study of coverage problem in uncertain WSN environment requires the consideration of this uncertainty by taking the best possible decisions, since it is impossible to explicitly represent all the combinatorics to produce a conditional active/passive state nodes' planning in the area of interest, and allow reasoning on various environmental states of the partially known physical world. This paper addresses the problem of area coverage based on the Dempster-Shafer theory. The authors aim to ensure the full area coverage while using a subset of connected nodes, with minimal costs using a minimal number of dominant nodes regardless of the type of used deployment (random or deterministic). This is ensured by activating a single node in each subset of each geographic sub-area, thus extending the lifetime of the wireless sensor network to its maximum. The comparison of the proposed model denoted evidential approach for area coverage (EAAC) with two well-known protocols and with a recent one showed a better performance and a slight improvement in the covered area.

Experimental Study on Swelling Behavior and Its Anisotropic Evaluation of Unsaturated Expansive Soil

Evaluation of swelling behavior is important for designing structures in expansive soils areas, especially for highway that the swelling pressure generated upon pavement and retaining structures in both vertical and horizontal directions due to infiltration. In this study, modification was made on unsaturated consolidation oedometer to provide synchronized measurement of vertical swelling strain (VSS) and lateral pressure (LP) of expansive soil under constant net normal stress and controlled matric suction. Vertical swelling (VS) test and lateral swelling (LS) test were conducted to investigate the anisotropic swelling behavior. The influence of mean net stress and net stress ratio on VSS was investigated, and the anisotropic swelling behavior of unsaturated expansive soil was characterized using anisotropic swelling ratio. The results show that the VSS nonlinearly decreased as the mean net stress increased and increased as the net stress ratio increased. The expansive soil would rapidly enter the passive state due to lateral swelling pressure under relatively low surcharge, with major principal axis rotating from vertical direction to lateral direction, which advances the possibility of passive failure for light retaining structures. The anisotropic swelling behavior objectively exists and varies with matric suction and net normal stress, which should not be ignored for engineering application.