Interdependence of fundamental and applied research in material science

Development of materials with desirable properties essentially depends on realization of interdependence: natural science ⇔ technical sciences. Taking this into account, in order to develop of new advanced materials it is essential to determine principles that characterize this interdependency. Therefore, in this article the principles of fundamental research and the importance of obtained results are considered and implemented in the field of technical realizations

The effect of structural changes on magnetic permeability of amorphous powder Ni80Co20

The structural changes of Ni80Co20 amorphous powder were tested during heating. The alloy was obtained by electrolysis from ammonia solution sulfate of cobalt and nickel on the titanium cathode. The differential scanning calorimetry (DSC) method was used to detect that the crystallization process of powder occurred in two stages with crystallization peaks temperatures of the first stage at 690 K and of the second stage at 790 K. The effect of structural relaxation and crystallization of powder on magnetic properties was predicted by measurement of the relative magnetic permeability change in isothermal and nonisothermal conditions. On the basis of the time change of relative magnetic permeability at a defined temperature in the temperature range of the first and second crystallization peak on the thermogram, the kinetics of crystallization was defined. It was predicted, that in the initial time interval, in the range of the first crystallization peak, the rate of crystallization is determined by the rate of nucleation of the amorphous part of the powder. However, in the second time interval, the crystallization rate is determined by the rate of diffusion. In the range of the second peak, in the beginning the rate of crystal growth is determined by activation energy of the atom pass from smaller to bigger crystal grain. In second time interval, the rate of crystal grain growth is determined by the diffusion rate of atoms to the location of integration into bigger crystal grains. For all processes which determine the rate of crystallization in temperature ranges of both crystallization peaks, the Arrhenius temperature dependence of rate for those processes is obtained. The relative magnetic permeability of crystallized powder at 873 K, is smaller for about 30 % than the relative magnetic permeability of fresh powder at room temperature. However, structurally relaxed powder at 573 K has an about 22 % larger magnetic permeability than the same fresh powder at room temperature

The changing roles of planning and the market in the processes of urban growth in Belgrade and Sofia

This paper studies the changing roles of planning and the market in the context of urban growth and suburbanization in the capitals of Serbia and Bulgaria, specifically with regard to the socio-economic changes experienced in Southeast Europe over the past decades. With a focus on the post-socialist period, the work also examines specific features of the socialist period, so as to make important distinctions between the two. The research question in this paper is: Is planning or the market responsible for the form of growth that has occurred in Sofia and Belgrade? One methodological problem for the study is that in reality, most urban processes are to a degree both market driven and centrally planned. Thus, it can be difficult to distinguish between the distinct roles and outcomes of planning and the market. To solve this problem, the paper analyzes situations in which either planning or the market is dominant, so as to be able to clearly determine the impact of each mechanism on the resultant development. The paper concludes that urban growth and suburbanization are generally engendered by market forces, whereas the role of planning is to improve and refine the action of the market. When planning ignores the market, it results in failed or inefficient urban forms. However when planning is absent, urban development fails to meet reasonable standards

Empirical Analysis of the Impact of Foreign Exchange Reserves to Economic Growth in Emerging Economics

In this paper we analyzed the effect of the accumulation of foreign exchange reserves to economic growth in emerging countries. In order to empirical estimates of the impact of foreign exchange reserves to economic growth in emerging countries, were collected annual data on real GDP per capita, share of investment in GDP and population from the database of the International Monetary Fund (IMF WEO) in October 2013, while data from the level of foreign exchange reserves statistics collected from the relevant central banks. For a balanced panel data for Brazil, China and Russia, for the period from 1993 to 2012, estimated the relationship between economic growth and changes in foreign exchange reserves by applying the method includes the ONK with fixed individual effects. The empirical results in this paper suggest that the increase in foreign exchange reserves causes the growth of GDP, while in the opposite direction causality has not been proven. Exchange rate depreciation that occurs as a result of the accumulation of foreign exchange reserves is not inflationary because it is a one-time, non-persistent shock, unlike the sudden depreciation of the exchange rate that occurs as a result of maintaining an overvalued exchange rate in the long term and leads to currency crisis. The accumulation of foreign exchange reserves does not lead to inflation if the rate of accumulation of foreign exchange reserves does not exceed the rate of economic growth. Slightly higher inflation is not necessarily harmful, particularly for developing economics and emerging economics

Occlusal Interferences in Localised and Generalized Periodontitis

Značaj okuzijskih zapreka u razvoju i u terapiji parodontnih bolesti i poremećaja iznimno je kontroverzan. Još uvijek su u najstručnijim krugovima znanstvenika aktualne rasprave o povezanosti zapreka i okluzijske traume i o njihovoj ulozi u parodontnoj bolesti. Svrha rada bila je istražiti postoji li statistički znatna razlika u pojavnosti okluzijskih zapreka ( na radnoj i balansnoj strani) između skupine pacijenata s lokaliziranim parodontitisom i skupine pacijenata s generaliziranim parodontitisom. Ispitanici su bili pacijenti s parodontnom bolesti, koji su klasificirani prema Extent and Severity Indexu (ESI) na ispitivanu skupinu lokaliziranih parodontitisa i ispitivanu skupinu generaliziranih parodontitisa. Kretnje na laterotruzijskoj strani/kontakti u interkaninom području tijekom protruzijske kretnje bilježene su plavim artikulacijskim papirom debljine 12µ, a kontakti na mediotruzijskoj strani/kontakti u lateralnim područjima tijekom protruzijske kretnje bilježeni su crvenim artikulacijskim papirom debljine 12µ. U obje ispitivane skupine 45,12% ispitanika imalo je zapreke na radnoj strani, a 48,78% ispitanika imalo je zapreke na balansnoj strani. U skupini lokaliziranoga parodontitisa 33,33% ispitanika imalo je zapreke na radnoj strani, a 50,81% ispitanika imalo ih je u skupini generaliziranoga parodontitisa. Zapreke na balansnoj strani postojale su u 52,38% ipitanika u skupini lokaliziranoga parodontitisa, a 47,54% ispitanika imalo ih je u skupini generaliziranoga parodontitisa. Hi-kvadrat testom utvrđeno je da ne postoji statistički znatna razlika između pojavnosti okluzijskih zapreka u skupini ispitanika s lokaliziranim parodontitisom u usporedbi sa skupinom ispitanika s generaliziranim parodontitisom. Iako nema statistički znatne razlike, postoji tendencija razlike u frekvencijama (p = 0,054) te je vidljivo da u skupini ispitanika s generaliziranim parodontitisom postoji više slučajeva bez zapreka na balansnoj strani (52,45%) u odnosu prema skupini ispitanika s lokaliziranim parodontitisom (47,61%). Rezultati ovog istraživanja pokazuju da ne postoji statistički znatna razlika u pojavnosti okluzijskih zapreka u skupini ispitanika s lokaliziranim parodontitisom i u skupini ispitanika s generaliziranim parodontitisom.The significance of occlusal interference in the development and therapy of periodontal disease is very controversial. There are still very vivid discussions going on between experts whether or not interferences cause occlusal trauma, and wath is its role in periodontal disease. The aim of the study was to investigate whether there i statistically significant difference in the manifestation of occlusal interferences (working side and balancing side) among a group of patients sufferig from localised periodontitis and a group of patients with generalized periodontitis. Examinees were patients with periodontal disease, classified according to Extent and Severity Index (ESI) into a group with localised periodontitis and a group with generalized peiodontitis. Movements on the laterotrusion side/contacts in the intercanine segment in protrusion were marked with blue articulation paper 12µ thick, while contacts on the mediotrusion side/contacts in lateral segments during protrusion were marked with red articulation paper (12µ thick). Of al patients, there were 45.12% with working side interferences, and 48.78% with balancing side interferences in both examined groups. 33.33% of the examinees in the group with localised periodontitis had working side interferences, and 50.81% of the examinees in the group with generalized periodontitis. Balancing side interferences were found in 52.38% of patients in the group with localised periodontitis, and 47.54% of patients in the group with generalized periodontitis. Chi-square test showed that there was statistically significant difference between manifestation of occlusal interferences in the group of patients with localised periodontitis compared to manifestation of articulation interferences in the group of patients with generalized periodontitis (chi-square = 3.561; p = 0.313). Although there was no statistically significant difference, there was a tendency to difference in frequencies (p = 0.054), and it is shown that in the group of patients with generalized periodontitis there were more cases with no balancing side interferences on any side (52.45%), compared to the group of patients with localised periodontitis (47.61%). Results showed that there was no difference in manfestation of occlusal interferences in localised peiodontitis compared to generalized periodontitis

The Determination of Paramagnetic Susceptibilities by High-resolution Nuclear Magnetic Resonance

Existing high-resolution NMR techniques for th e determinat ion of the magnetic susceptibilities of paramagne tic materials in solu tion are reviewed critically and the underlying theory is discussed. Attempts t o measure th e effect of interaction between indicator protons and para m agnetic ions suggest that, in the cases examined, this is less imp orta nt than the change in field or frequency con sequent on the insertion of paramagnetic material in the probe of a field/frequency locked spectrometer. Several variants of the substitution method have been tested. Provid ed that the calibration factor appropriate to the combination of tube and probe has b een d e termined, a simple substitution method i s practicable but, on the whole, the internal/external ·reference method with spinning concentric cylindrical samples is to be preferred

Mechanical-chemical synthesis Ba0.77Sr0.23TiO3

Barium-Strontium-Titanate Ba0.77Sr0.23TiO3 was prepared from starting materials BaCO3, SrCO3 and TiO2 through solid-state reactions. Mixtures of these oxides are mechanically activated in a high-energy planetary ball mill at different time intervals from 0 to 120 minutes. In order to obtain information on phase composition, crystal structure was determent by X-ray diffraction. It was observed that after 80 minutes in process synthesis Ba0.77Sr0.23TiO3 started Thermal analyzes were performed in order to determine the characteristic temperatures of the processes that occur in the solid phase. Particle size distribution, together with electron microscopy scanning has given us very useful information about the morphology of the powder

Hydrogen Adsorption Process In Nanocrystalline Nuclear Graphite

Kinetics and mechanism of hydrogen adsorption in as-obtained and ground nuclear graphite Wendelstein 7-X are examined. In the first time interval the adsorption process is determined by dissociation of the hydrogen molecule, occurring at the outer surface and in open micropores of nuclear graphite particles. However, in the second time interval, the slowest step in the hydrogen adsorption is inter-granular and inter-crystallite diffusion in nanopores of graphite. The X-ray analysis shows, that grinding of as-obtained nuclear graphite results in finer particles with finer nanocrystals and larger density of opened pores and carbon reactive sites. The capacity and rate of adsorption increase with comminution of nuclear graphite particles and adsorbed hydrogen does not sub stantially alter the microstructure of nuclear graphite

Attitudes, Behaviour and Knowledge on Sexuality among Female Adolescents in Zagreb, Croatia

The aim of this study was to estimate the level of knowledge about sexuality, attitudes and sexual behaviour of female adolescents. The study included 194 female students, 117 from Medical High School (MHS) and 77 from General High School (GHS) in Zagreb. Data was collected using an anonymous self-administered questionnaire. In addition to items on personal data (age, parental education etc.), the participants were asked to define terms about sexuality (e.g. menstruation, puberty) the definitions of which are found in biology textbooks for the fifth and eighth grade of primary school. The aim of the third part of the survey was to collect information about attitudes and behaviour of female adolescents. The results showed a low level of knowledge in students of both schools. General High School students showed a higher level of knowledge than their Medical High School peers. One fifth of General High School students and 1/3 of Medical High School students were unable to define the term »menstruation«. The majority of adolescents talk about sexuality with their friends, 92.1% of General High School and 81.2% of Medical High School students. Almost 50% of students of both schools would like to talk about sexuality with their school doctor. 6.9% of Medical High School students had at least one sexual intercourse while none of the General High School students had been sexually active at the time of the survey. As the majority of students were not sexually active and results showed a rather low level of knowledge, this seems to be the ideal period for the implementation of educational programs aimed at increasing the level of knowledge, and thus preventing unwanted consequences (STD, pregnancy, abortion, infertility)

Polarimetric Properties of Flux-Ropes and Sheared Arcades in Coronal Prominence Cavities

The coronal magnetic field is the primary driver of solar dynamic events. Linear and circular polarization signals of certain infrared coronal emission lines contain information about the magnetic field, and to access this information, either a forward or an inversion method must be used. We study three coronal magnetic configurations that are applicable to polar-crown filament cavities by doing forward calculations to produce synthetic polarization data. We analyze these forward data to determine the distinguishing characteristics of each model. We conclude that it is possible to distinguish between cylindrical flux ropes, spheromak flux ropes, and sheared arcades using coronal polarization measurements. If one of these models is found to be consistent with observational measurements, it will mean positive identification of the magnetic morphology that surrounds certain quiescent filaments, which will lead to a greater understanding of how they form and why they erupt.Comment: 22 pages, 8 figures, Solar Physics topical issue: Coronal Magnetis