The flora of the volcanic island of Brusnik (central Dalmatia, Croatia)

Research into the vascular flora of the volcanic island of Brusnik was carried out in the period from 2000 to 2002. A total of 28 higher plant species was found, four of them being noted for the first time. Of the 41 taxa noted by previous authors, 24 were confirmed, but 17 were not. According to analysis of life forms, the most numerous are Therophyta (13 species, 46.4%), followed by Chamaephyta (seven species, 25%), Phanerophyta (four species, 14.3%), Hemicryptophyta (three species, 10.7%) and Geophyta (one species, 3.6%). After analysis of floral elements, autochthonous taxa are grouped into three categories: Mediterranean floral element (18 species, 66.6%), South European floral element (five species, 18.5%) and widespread plants (four species, 14.8%). Especially important plants in the flora of Brusnik are Frankenia pulverulenta L., a very rare species in the Croatian flora and the Illyrian-Adriatic endemic plants Centaurea ragusina L., Limonium vestitum (Salmon) Salmon subsp. brusnicense Trinajsti} and Senecio leucanthemifolius Poir. var. reichenbachii Fiori. The results of our research show that the island of Brusnik belongs, in phytogeographical terms, to the Mediterranean zone proper of the Mediterranean region

Prilog flori otoka Malog Drvenika

Since there has been to date no account of the flora of the island of Mali Drvenik, we have begun floristic research that is still in progress. We have found 100 taxa of vascular plants (36 families), recorded for this island for the first time.Prigodom florističkih istraživanja na otoku Malom Drveniku pronašli smo 100 svojti vaskularnih biljaka (svrstanih u 36 porodice) koje dosad nisu bile zabilježene na ovom otoku. Floristička istraživanja se nastavljaju

Electronics ceramics grain boundaries and complex fractal dimension

Analysis of ceramic grain boundaries, esspecially for BaTiO3 , is also important for its dielectric and conductive properties. In this regard, the fractal analysis was highlighted. The grain contacts geometry based on intergranular contact surface fractal morphology was the subject of our long term research. A new approach based on complex dimension fractal geometry and correlation between microstructurenanostructure and rare-earth properties and other additives doped BaTiO3-ceramics and electronics properties, is applied . In addition to the continuous type of scaling typical for real standard fractal objects, complex objects are considered here, which also have a discrete scaling symmetry with logarithmic space period. That rely on their appearance on the various , micro and macro, electrical and other properties of BaTiO3-ceramics

Characterization of ptc effect in batio(3)-ceramics as a special phase transition - fractal approach

The applications of BaTiO3-ceramics are very important and constantly increasing nowadays. In that sense, we analyzed some phenomena related to inter granular effects. We used experimental data based on Murata powders and processing technology. Our original contribution to Heywang-Jonker-Daniels inter-granular capacity model is based on thermodynamic fractal analysis applied on phase transition in ceramic structures. In this case, PTCR effect has a diffuse first-order phase transition character in a modified Landau theory-fractal approach. Its basic properties are considered. This is an original contribution as a bridge between theoretical aspects of BaTiO3-ceramics and experimental results

Microelectronics miniaturization and fractal electronic frontiers

The intergrain ceramic structures are very complex and difficult to describe by using traditional analytical methods. In this study, in order to establish grain shapes of sintered ceramics, new approach on correlation between microstructure and properties of doped BaTiO3 -ceramics based on fractal geometry has been developed. BaTiO3 ceramics doped with CeO2, Bi2O3, Fe2O3, CaZrO3 Nb2O5, MnCO3 , La2O3, Er2O3, Yb2O3 and Ho2O3, were prepared using conventional solid state procedure and sintered at 1350°C. The sintered specimens microstructure was investigated by SEM-5300 and capacitance has been done using LCR-metra Agilent 4284A. The fractal modeling method using a reconstruction of microstructure configurations, like grains or intergranular contacts shapes has been successfully done. Furthermore, the area of grains surface was calculated by using fractal correction which expresses the grains surface irregularity through fractal dimension. For better and deeper the ceramics material microstructure characterization the Voronoi model and mathematical statistics calculations, are applied, also. The fractal nature for ceramics structure analysis providing a new ideas for modeling the grain shape and relations between the BaTiO3 ceramic structure and dielectrical properties and new frontier for higher integration on electronic circuits. The presented results indicate that fractal method for structure ceramics analysis creates a new approach for describing, predicting and modeling the grain shape and relations between the BaTiO3 -ceramic structure and dielectric and generally electric and microelectronics properties

Generalized Lorentz model description of electrical, dielectric, conductive and magnetic processes two-time relaxations in BaTiO3 ceramics with constitutive relations

In this study, generalized Lorentz model is considered in the framework of dielectric, conductive and/or magnetic responses of materials. Beside positive temperature coefficient of resistivity (PTCR) materials (current stabilizers, time delay circuits and current limiters for overvoltage or overcurrent protection, temperature sensors, self-heating, …), magnetic properties indicate to multifunctional or specific applications (for example, nanocubic technologies). AC conductivity studies of various BaTiO3 ceramics or similar ceramics produced equivalent circuits with impedance spectra, usually within the framework of RCPE elements serial connection (CPE - constant phase element) or Cole element. One of the first models that explains PTC effect is the Heywang model, in terms of grain boundaries potential barriers of the Shottky type. Dielectric frequency spectra can be described in similar relationships. However, magnetic features of BaTiO3 ceramics are not well described. In this presentation all three behaviors (dielectric, conductive and magnetic) of materials and their relationships are considered in the case of electric or magnetic alternate fields, which are the basis for experimental measurements

Complex fractal dimension and possible application in electronic ceramics

Considering the extremely growing exigency for further miniaturization and a higher level of packaging of electronic circuits and components, this paper is aimed at developing a more sophisticated application of fractals. In this sense, the progress in the development of the mathematical-physical tool in further upgrading of fractal microelectronics is presented here. Barium titanate samples with bayi yttrium samples are used as the experimental basis under conditions of using the highest levels of nanotechnology, especially grain deposition. In this regard, the ideas of complex fractal analysis will be elaborated in this paper. Examples of complex fractal dimensions are known in the literature. The relationship between fBm (Fractional Brown motion) and Bm is given by the left-sided Riemann-Liuville fractional integral When is H=0.5, in the above equation, fBm and Bm is matching.For H >0.5 the process is positive, and for H <0.5 negatively correlated. It shows that the imaginary part of the fractal dimension is translated into log-periodic modulation, which completes the behavior by leading a degree law, and is based on discrete fractal symmetry. In particular, complex Brownian motion can be generated based on 1d complex Brownian motion in matlab code. There is also a corresponding fractional calculus of complex order. Other parallels with electrical processes in BatiO3 ceramics are also possible