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Nutrition is one of the most important issues in patients with chronic kidney disease, especially in those undergoing chronic hemodialysis. Advanced kidney disease and renal replacement therapy lead to a number of metabolic and nutritional disorders, which can be called loss of protein and energy in chronic kidney disease. Health education of patients includes giving advice on the lifestyle at home, the importance of regular check-ups and the importance of adhering to a diet and controlled, thus dosed physical activities.

The effect of Nb on the microstructure and dielectric properties of BaTiO3 ceramics was investigated. The Nb/Mn–BaTiO3 ceramics were prepared using a conventional solid-state method. The concentration of Nb varied from 0.1 to 5.0 at% but Mn was fixed at 0.05 at%. The SEM indicated that compositions of 0.1 and 0.5 at% Nb displayed a fairly uniform microstructure and homogeneous distribution of additives, with a grain size of less than 2 μm. In highly doped samples a wide range of microstructural features was observed, from homogeneous and completely fine-grained microstructure to the appearance of secondary abnormal grains with core-shell structure. The dielectric constant and the loss tangent of modified ceramics were measured as a function of temperature (20–180 °C) and frequency (100 Hz-1MHz) for different concentrations of additives. The obtained results have shown that the dielectric constant at, both, room temperature (er) and Curie temperature (ermax), decreased as the concentration of Nb5+ increased. Thus, the highest values for the dielectric constant at room temperature (er = 6648) as well as at Curie temperature (ermax = 7680) were measured for the 0.1Nb/Mn–BaTiO3 samples sintered at 1350 °C. The highly doped BaTiO3 ceramics were found to exhibit lower values of the dielectric constant and low dielectric losses at room temperature. In these samples, stable dielectric permittivity with a flat dielectric behavior over a wide temperature range is observed. The Curie constant for all series of samples decreases with an increase of dopant concentration and the highest values were measured from samples doped with 0.1 at% Nb. The effect of additives on the Curie constant change is more pronounced at higher sintering temperatures. The analysis of the critical nonlinearity exponent (γ = 1.07–1.27), for lower dopant concentrations, shows a sharp phase transformation. For samples with increased Nb content, the degree of nonlinearity γ is higher indicating a diffuse phase transformation.

The microstructures properties predicting are based on their materials characteristics. In ceramic materials, regarding higher miniaturization and integrations, the structure analysis is very important. The main contribution of this research is related to relation between perovscites ceramics electronic properties, especially BaTiO3 and NZT-ceramics and structural characteristics. We applied advanced analysis, based on fractal nature and introduced complex fractal correction in defining the very important electromagnetic parameter inductivity (L). The samples consolidation includes both, powder pressing (cold sintering) and hot sintering. The fractal characterization performs very important role from powders up to the final structures, through which exists structure influence on electro-physical and other ceramic properties. We report the experimental results of BaTiO3 and NZT-ceramics processing. Also, this is the first time that we apply complex fractal correction (influence of grains and pore surface and as well as particles Brownian motion) on fundamental thermodynamic temperature in Currie-Weiss law. This application includes the influence of Housdorff dimension (DH) from the microstructure images and connect fractal corrections in Currie-Weiss law, for relative dielectric constant ϵr and magnetic permeability μr. Through ϵr and μr, on this way, for the first time in this scientific area, we present direct relation to inductivity. This complex relation opens quit new advance understanding in structures and parameters in area of ferroelectic-magnetic applications in telecommunications, by introducing the fractals. acceptedVersion

The electrical conductivity, phase, and space group of property of the NMT substance and grain boundary of samples were approximated from complex compound by Raman spectroscopy, X-ray, SEM, TEM, and differential scanning calorimeter (DSC), samples prepared and analyzed in the laboratory in the frequency ranges from 9.76 GHz. The solid-state conventional method utilized. All the samples were tested by using XRD from 1250°C to 1550°C by increasing 50 degrees for every sample and cooling to the room temperature. The contraction of structure did not happen even at elevated temperature. The increase in Nd+ ion polarizability is 0.50 nm compared to La+ rare elements material, which is 0.60, this contributes to change of perovskite cubic. This is result of the smaller size of Nd+ 0.127 nm cation compared to La+ which increase number of dipoles despite the reduction of diploes and expands relative permittivity (εr). The single-phase material produced which shows quality factor Q×f = 60000 saturated at 10 GHz and temperature coefficient of (τf) = -77 MK-1. acceptedVersion

The effects of Nb/Mn and La/Mn on the electrical properties of doped BaTiO3 ceramics were investigated in this paper. A series of Nb/Mn and La/Mn-doped BaTiO3 samples, with dopant concentrations, ranged from 0.1 up to 2 at% of La and Nb, were prepared. The Mn concentration of 0.01at% was the same in all samples. The samples have been sintered at 1300°C for two hours. SEM analysis indicated a fine-grained microstructure with grain size less than in La/Mn-BaTiO3. For the same concentration of additives, the bimodal microstructure was observed in Nb/Mn-BaTiO3. Samples with a low concentration of additives (0.1 and 0.5at%) show a higher dielectric constant value. A stable dielectric permittivity with a flat dielectric response in the transition zone is observed in high doped ceramics. Higher dielectric constant values were measured for samples doped with Nb and ranged from 1790 to 4027 at room temperature. The shift of Curie temperature towards lower temperature has been noticed in all samples. The Curie-Weiss law was used to analyze the permittivity behavior in the paraelectric region.

It is of great interest to determine the relation between biophysical and condensed matter systems, because this biomimetical approach provides new frontiers for further microelectronic circuits integrations. Molecular and submolecular particles are identical in living and nonliving organisms, which implies the possibility of considering these particles motion as the biunivocal phenomenon. Brownian motion and its fractal nature, as a general phenomenon existing within both systems, is an integrative property based on which we can establish the relation between these two systems. We used some experimental data, based on the bacterial motion experiments, regarding influence of different energy impulses on bacterial trajectories. The goal of this research is to introduce the asymptotic approaching of biophysical and condensed matter systems, based on Brownian motion fractal nature similarities, presented in mathematical analytical forms.

There is a progressing interests for polycrystalline diamonds and they have been more extensively used recently. This area has been intensively researched due to the outstanding potential of this material, and this necessitated presenting some of the latest application related to engineering in this paper. A better insight of polycrystalline diamonds properties can be achieved by intensively researching the surface structure. Samples of nanocrystalline diamonds grown by the chemical vapor deposition method are analyzed and accordingly, the focus of the research was the surface parameters and their structure. It is observed that waviness and texture are unique for any direction, their values are almost the same for the chosen directions and they vary approximately from -0.2 nm to 0.4 nm. Analyses of the parameters allowed a more detailed insight into the morphology of the surfaces of polycrystalline films. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI 172057]

Barium titanate (BaTiO3) attracts high scientific and technological attention due to good dielectric and electromechanical properties. Although BaTiO3 is one of the most frequently investigated ferroelectric materials, the need for finding new and/or improved synthesis methods of this material still exists. In this paper, a novel, mild synthesis route for producing tetragonal BaTiO3 from barium nitrate and Ti-oxalate precursor is presented. Morphology of the prepared and subsequently sintered BaTiO3 was determined by SEM. Particle size distribution of the as prepared powder was monitored by the laser diffraction. The phase composition, structure and lattice dynamics were investigated by XRD and Raman spectroscopy. Finally, dielectric parameters were determined in the temperature range from 30 to 180?C, and within a variety of frequencies. Curie temperature was detected at 130?C.

With a special focus on the now widespread Internet of Things (IoT) technology, it offers a convenient solution for smart agriculture. This paper will introduce a smart greenhouse monitoring and control data logger system as part of a smart farm. The system is based on: a group of built-in sensors, a microcontroller with a peripheral interface (PIC) as a core and a server system and a wireless Internet using the Global System of Mobile Telecommunications (GSM) module with General Packet Radio Service (GPRS) as a communication protocol. It is possible to implement a smart agricultural service, in which the realized smart data logger system could be implemented, which enables automatic control of the greenhouse at the farm.

The Global Energy Crisis necessitated improving research into new, renewable and alternative energy sources. Due to that, our focus is on the area of some phenomena and applications where different synthetic methods and micro-structure property optimization achieved significant improvement in the electro physical properties of output materials and components. This is especially important for higher energy efficiency and electricity production (batteries and battery systems, fuel cells, and hydrogen energy).The improvement of energy storage tank capacity is one of the most important development issues in the energy sphere too. It is because of this very promising research and application area that we are expanding the knowledge on these phenomena through fractal nature analysis. So, the results obtained in the field of electrochemical energy sources, especially in electrolyte development, are taken into account the analysis of fractal nature optimization. Based on the research field of fractal material science, particularly electronic materials, we conducted research in micro-structure fractal influence in the area of electrochemistry. We investigated the consolidation parameters of Fe2O3 redox processes. The influence of activation energy, fundamental thermodynamic parameters, and also the fractal correction of electrode surface area through complex fractal dimension with recognized grains and pores, and the Brownian motion of particles is introduced. Finally, the electrochemical Butler-Volmer equation fractalization is obtained. These results practically open new frontiers in electrochemical energy processes performed through the Arrhenius equation within electrolyte bulk and electrode relations and more complete and precise energy generation.

The dielectric properties of Neodymium zinc titanium oxide (NZT) and Neodymium magnesium titanium oxide (NMT) were investigated. The single-phase ceramic was synthesized at various temperatures below 1650[Formula: see text]C. The result shows that the value of temperature of resonant frequency [Formula: see text] for NMT is higher than NZT. Our findings also indicate that the rare earth materials produce high property dielectric materials, despite the fact some elements produce lower negative value of temperature of resonant frequency [Formula: see text]. By doping a compound such as CaTiO3 which has a very positive temperature of resonant frequency ([Formula: see text] ppm/[Formula: see text]C) and a very high relative permittivity [Formula: see text], it is possible to tune NZT and MNT to achieve an excellent dielectric material. This work is under consideration. The results of this scientific research could be very important for modern advance applications in microelectronic miniaturization.

The focus of this study is on the control of layers between grains by applying graph theory. We performed modification of BaTiO3 nanoparticles with Y2O3. The results of capacitance change on submicron level are the part of the measured values on the bulk samples. The original idea is to develop the new approach to use graph theory for networking of electronic parameters between the neighboring grains in order to compare the values measured on the sample, and to present them through the edges in graph between corresponding vertices. Capacitance change with DC bias was measured on bulk samples, and the modified nanoparticles showed stability up to 90 V. After using graph theory with the different number of neighboring grains and on different voltages, it has been shown that capacitance change can be successfully calculated on the layers between grains. Original calculations presented as 1D cases were performed, confirming graph application as a tool with which measured bulk results can be downsized to an appropriate intergranular level, opening the new perspectives in the area of miniaturization and micropackaging.

Donor/acceptor (La/Mn) doped BaTiO3 ceramics, sintered at different temperatures, were studied regarding their microstructure and dielectric properties as well as the dielectric response in a ferroelectric/paraelectric regime. The concentrations of La3+ as donor, ranging from 0.1 to 5.0 at% were used for doping, while a content of Mn4+ as acceptor was at 0.05 at% in all samples. The sintering temperature of codoped samples were 1290? and 1350?C. A reduction in grain size and fine-grained microstructure with average grain size from 0.5 to 2.0 mm was observed in low doped samples, whereas the abnormal growth of individual grains took place in the 2 at% and 5 at% La doped specimens. The dielectric properties of these samples were investigated as a function of frequency (100Hz - 20 kHz) and temperature (20-180?C). The measured results suggested that both the dielectric constants of the ceramics (er at room temperature and ermax at the Curie temperature) decreased as the concentration of La3+ increased. The dielectric permittivity was in the range of 944 to 3200. For samples doped with 0.1 at% La and sintered at 1350?C, the highest dielectric constant value at room temperature (er= 3200) and Curie temperature (er= 5000) were measured. For all measured samples the dissipation factor was less than 0.09. With an increase in La contents, dielectric measurements exhibited shift in the Curie temperature (Tc) towards the low temperature. Using the Curie-Weiss and the modified Curie-Weiss law, Curie's constant C was calculated as well as the parameterg, which describes the deviation from the linear dependence er of T above the phase transformation temperature. The calculated values for g ranged from 1.01 to 1.43. These values indicate a sharp phase transformation in lowdoped and diffuse phase transformation in highly La doped samples. The phase transition was reflected in the values of C that started to decrease with increasing dopant content.

The microstructure characteristic and dielectric properties of doped BaTiO 3 -ceramics were investigated in the light of the Clausius–Mossotti relation (CMR) which incorporates both the Curie and Curie–Weiss Laws. The samples of doped BaTiO 3 ceramics were prepared using conventional solid state procedure and sintered from 1290 °C to 1320 °C. Microstructural and compositional studies were performed by SEM equipped with EDS system. The Clausius–Mossotti relation is used to clarify the influence of dopant on the dielectric properties and BaTiO 3 phase transformation. Curie parameters (C, Tc) were calculated by using a Curie–Weiss law. Also, a new approach on correlation between microstructure and dielectric properties of doped BaTiO 3 based on fractal nature analysis (grains shapes, pores and intergranular contacts) have been developed, by using fractals in microstructure configurations reconstruction. This includes reconstruction of grain surface i.e. pore surface as tensor product of appropriate fractal curves. Particles chaotic motion trajectories is considered as Brownian motion which is then linearized in fractal manner. Fractality of grain surface, pore surface and particle motion introduce three fractal factors. Our hypothesis is that working temperature of BaTiO 3 -ceramics must be influenced by ceramics material fractality; these three fractality factors, appear as a correction of theoretic temperature appearing in Clausius–Mossotti relation i.e. Curie–Weiss law. © 2018, © 2018 Taylor & Francis Group, LLC.

BaTiO3-ceramics is a porous material made out of grains and pores. Such a structure is best explained by fractal nature approach. There is a strong porosity influence on microelectronic properties,...

This paper is focused on the research an improved version of the Boltzmann-Poisson model for BaTiO3-ceramics. In the approximation of one relaxation time, for constant external electrical field, this approach included correct quadratic relation for varistor effect in the case of the Heywang model. Within meso-kinetics, quantum corrected Boltzmann-Poisson model, contains space-time correlations for the probability distribution density function f(r, k, t), lead to correct fractional relaxation velocity description. These new results corresponds to our other research based on electronic particles Brownian motion within its fractal nature.

The BaTiO3 ceramics applications based on electronic properties have very high gradient scientific and industrial-technological interests. Our scientific research has been based on nano BaTiO3 modified with Yttrium based organometallic salt (MOD-Y). The samples have been consolidated at a sintering temperature of 1350 &deg, C. Within the study, the new frontiers for different electronic properties between the layers of BaTiO3 grains have been introduced. The research target was grain boundary investigations and the influence on dielectric properties. After scanning electron microscopy and dielectric measurements, it has been established that modified BaTiO3 samples with larger grains showed a better compact state that led to a higher dielectric constant value. DC bias stability was also investigated and showed a connection between the grain size and capacitance stability. Analyses of functions that could approximate experimental curves were successfully employed. Practical application of fractal corrections was performed, based on surface (&alpha, s) and pore size (&alpha, p) corrections, which resulted in obtainment of the relation between the capacitance and Curie temperature. Successful introduction of fractal corrections for capacitance-Curie temperature dependence for a set of experimental data is an important step towards further miniaturization of intergranular capacitors.

Article describes a method for automating measurement and characterization of electrical materials at low and medium frequency. For measurement and characterization are used LCR meter for measuring material parameters as function of frequency and furnace for testing electrical materials at different temperature. For the measurement and characterization of electrical materials, an application was developed that automates the control of the measuring system. Based on this it has been shown that measurement of material characteristics can be performed without the presence of a human factor. For testing the method, doped BaTiO 3 ceramic samples are used.

The effect of rare earth ions on dielectric permittivity, dielectric losses and microstructure of barium titanate ceramics doped with Ho, Er and Yb at the concentrations of 0.05 wt% to 1.0 wt% was investigated. The doped BaTiO 3 were obtained by solid-state sintering reaction at a temperature of 1320°C in air atmosphere. The electrical properties were measured in the temperature interval from 30°C to 180°C at different frequencies. The results of electrical investigation showed that samples doped with a low additives concentration, with a spherical and large grains, have high dielectric constant value. e r at Curie temperature is 4250, 3828 and 3011 for 0.05 wt% Ho, Er and Yb respectively. By increasing dopant concentration and decreasing grain size, the dielectric permittivity value decreases. All investigated samples have low values of dielectric losses ranged from 0.01 to 0.09. Also, samples with a low concentration of additives follow Curie-Weiss‘s law. The Curie temperature of doped samples is slightly lower than Curie temperature of the undoped ceramics and it is 126-128 °C. The Curie constant $C$ for all examined samples increases with increasing dopant concentration, so that the highest values were measured for the samples doped with 1.0 wt% of the additive.

Post-sintering of magnesium titanate ceramics by hot isostatic pressing (HIP) in an oxygen-free atmosphere significantly alters various electrical properties of the product. In particular, the sintered material becomes a semiconductor. The aims of this paper are: to extend our investigations of the electrical properties of this material by expanding the frequency range of measurements, to design interpolation formulas for the frequency dependence of the complex relative permittivity, and to propose HIP-sintered magnesium titanate as a material for thermistors that have a negative-temperature-coefficient resistance (NTCR), as well as for varistors. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR 32005 and Grant no. ON 172057]

In this study, the electrical resistivity (ρ) and PTC effect of Er doped BaTiO3 ceramics are investigated. The concentrations of Er2O3 in the doped samples vary from 0.01 to 1.0 at% Er. The samples are prepared by the conventional solid state reaction, and sintered at 1320° and 1350°C in air atmosphere for 4 hours. The SEM analysis shows that all of measured samples are characterized by polygonal grains. The uniform and homogeneous microstructure with grain sizes from 20 to 45μm is the main characteristic of the low doped samples (0.01 and 0.1 at% Er). For the samples doped with the higher dopant concentration (0.5 and 1.0 at%) the average grains sizes have been ranged from 5 to 10 μm. The electrical resistivity is measured in the temperature range from 25°C to 170°C, at frequencies 1 kHz, 10 kHz and 100 kHz. The electrical resistivity values, measured at frequency of 1 kHz and room temperature, have been ranged from 1.62•104 Ωcm to 4.24∙104 Ωcm, for samples sintered at 1320°C and from 1.43•104 Ωcm to 1.94∙104 Ωcm, for samples sintered at 1350°C. A nearly flat and stable electrical resistivity-temperature response is characteristic for all samples at the temperature range from 25°C to 120°C. Above this temperature, the electrical resistivity increases rapidly. At 170°C the value of electrical resistivity is ranged 9.84•104 Ωcm -1.62•105 Ωcm, for Tsin=1320°C, and 6.11•104 Ωcm 1.32•105 Ωcm, for Tsin=1350°C. The electrical resistivity decreases with concentration increment up to 0.5 at%, while above 0.5 at% it increases. Also, with increasing frequency, ρ decreases for a few orders of magnitude. [172057: Directed synthesis, structure and properties of multifunctional materials]

Sm/Mn codoped BaTiO 3 ceramics were investigated for their microstructure and dielectric characteristics. The powders were prepared by the conventional solid state procedure. The concentration of Sm 2 O 3 as a donor dopant has been kept from 0.1 up to 5.0 at%. The content of MnO 2 as acceptor was kept constant at 0.05 at% Mn in all samples. The specimens were sintered at 1290 °C, 1320 °C and 1350 °C in an air atmosphere for two hours. A mainly uniform and homogeneous microstructure with average grain size ranging from 0.3 µm to 2.0 µm was observed in low doped samples. In highly doped samples, apart from the fine grained matrix, the appearance of local area with secondary abnormal grains was observed. The dielectric properties were investigated as a function of frequency and temperature. The low doped samples exhibit the high value of dielectric permittivity at room temperature and the greatest change at the Curie temperature. The highest value of dielectric constant ( e r =6800) was measured for 0.1Sm/BaTiO 3 samples sintered at 1350 °C. A nearly flat permittivity-temperature response and lower values of e r were obtained in specimens with 2.0 and 5.0 at% additive content. The dielectric constant increases with the increase of sintering temperature. The dissipation factor ranged from 0.01 to 0.22 and decreases with the increase of sintering temperature. The Curie constant ( C ), Curie-Weiss temperature ( T 0 ) and critical exponent of nonlinearity ( γ ) were calculated using a Curie-Weiss and modified Curie-Weiss law. The highest value of Curie constant (C=9.06·10 5 K) was measured in 0.1 at% doped samples. The Curie constant decreased with increasing dopant content. The γ values, ranging from 1.001 to 1.58, point out the sharp phase transition in low doped samples, and the diffuse phase transition in heavily doped BaTiO 3 samples.

Doped ceramics materials structure can be controlled using different synergetic effects as well as consolidation parameters. Additives concentration influence on ceramics microstructure and dielectric properties, based on fractal geometry, is analyzed. These properties level control level is very important in advanced materials prognosis. The Coble's two-sphere model is used as initial one, for developing a new two-ellipsoid model; unlike the spherical geometry, the ellipsoidal-polyhedral geometry,besides better approximation of sintering particles, is in relation with consolidation parameters (sintering time and temperature). The experiments have been based on BaTiO3 with different additives (CeO2, MnCO3, Bi2O3, Fe2O3, Nb2O5, CaZr2O3, Er2O3, Yb2O3, Ho2O3), concentration from 0.01wt% to 1wt%, consolidated under the pressing pressure up to 150 MPa and 1180°C-1380°C sintering temperatures, are used. We performed SEM and EDS analysis.The fractal nature offers a new approach for the ceramics structure analysis, describing, prognosis and modeling the grains shape and relations between ceramics structure and electric-dielectric properties. The microstructure has a great importance from different alternative energies points of view. World’s interest race in renewable and new generation energy sources development, especially the new batteries systems, are in research and development focus, simultaneously, in the electric cars technologies development. Beside the electrochemical processes and rechargeable speed, the storage capacity has special significance which is enriched by the fractal natureanalysis and these scientific paper contributions with some fundamental electrochemical laws through fractal corrections expressed by the relevant formulas. These are the new frontiers in direction of electrochemical fractal microelectronics. Also, the wind energy as new and alternative energy source has important role growing.The land and obstacles of fractal nature, influence on air/wind turbulence towards the wind generators propellers, has special effect on the wind speed, described by the logarithmic law equation which is deduced from the similarity theory that is strictly applicable to steady-state horizontally homogeneous conditions in the surface layer. So, definitely in this paper the fractal nature independently existing everywhere within the structures, contact surfaces, practically, from microstructures, even on nano level up to global bulk and massive shapes, fractal nature ceramics materials existence is completely confirmed within the electrochemical thermodynamic and fluid dynamics parameters, are confirmed.

Dye-sensitized solar cells are the closest mankind has come to replicating nature?s photosynthesis. The type of a dye influences the efficiency of these cells. In this paper we studied curcumin dye as a sensitizer in dye-sensitized solar cells and compared it with most often used cyanidin. The results have shown that curcumin has higher efficiency and higher absorption in the visible part of the spectrum compared to cyanidin. Simulation models of dye molecules, curcumin and cyanidin, are deprotonated upon adsorption on the titanium dioxide surface. The energy levels obtained from the calculation indicate a higher probability of electron transition from molecule to titanium dioxide surface in case of curcumin than in case of cyanidin. Based on these results, we concluded that curcumin dye has better properties as sensitizer in dye-sensitized solar cells.

Consolidation parameters have influence and can be used to control structure of BaTiO3 based materials. Microstructure and dielectric properties of Yb2O3 doped BaTiO3-ceramics, sintered from 1320 °C to 1380 °C have been investigated. The correlation between microstructure, capacity and dielectric properties of doped BaTiO3-ceramics, based on fractal geometry and micro-contact surfaces, has been developed. Using the fractal descriptors of the grains contact surface, the microstructure reconstruction constituents, as grains and pores shapes or intergranular contacts, has been successfully done. Obtained results indicated that fractal analysis contact surfaces descriptors of different shapes are very important for the prognosis of BaTiO3-ceramics microstructure and capacity and dielectric properties. The morphology of ceramics grains pointed out the validity of developing new structure analytical methods, based on different grains’ shape geometries. The grains contact structure based on Minkowski hull is presented as a new tool for BaTiO3-ceramics materials structure research. The materials properties prognosis are determined according to the correlations synthesis–structure–property, within Minkowski hull fractal frame. © 2019, © 2019 Taylor & Francis Group, LLC.

The new frontiers open different directions within the higher and deeper knowledge structure using unemployed nano sizes domains. The BaTiO3 and other ceramic materials have fractal configuration nature based on three phenomena. First, ceramic grains have fractal shape looking as a contour in cross section or as a surface. Second, there is the so-called “negative space” made of pores and intergranular space. Third, there is fractal Brownian motion (fBm) within the material, during and after sintering, in the form of microparticle flow: ions, atoms, and electrons. Here, we took upon ourselves the task of extending Coble’s model, with already generalized Euclidean geometries, by fractal nature correction. These triple factors make the very peculiar microelectronic environment electro-static/dynamic combination. The stress is here set on inter-granular micro-capacity in function of higher energy harvesting and storage. Constructive fractal theory allows identifying micro-capacitors with fractal electrodes. The method is based on the iterative process of interpolation which is compatible with the grain model itself. Inter-granular permeability is taken as the fundamental thermodynamic parameter function of temperature and enthalpy (Gibbs free energy), which are very important for a structure-energy relation.

The world's perennial need for energy and microelectronic miniaturization brings with it a broad set of technological and scientific challenges. Materials characterized by precise microstructural architectures based on fractal analysis and ranging in size down to nano scale represent an important avenue for finding novel solutions. Deep materials structure hierarchies of this type open new possibilities in capacity according to the Heywang model, especially when extended by a fractals approach and intergranular relationships supported and recognized by their fractal nature. These developments are opening new frontiers in microelectronics miniaturization. They build on early fractal applications that were used as tools in miniaturization research and also provided application perspectives for diverse energy technologies. In other words, fractals, as a crucial concept of modern theoretical-experimental physics and materials sciences, are tightly linked to higher integration processes and microelectronics miniaturization. They also hold potential for meeting the energy exploitation challenge. In this research context, for the first time we experimentally and theoretically investigated the electrostatic field between the grains within fractal nature aspects. It is essentially a theoretical experiment based on samples of experimental microstructures imaged with SEM, as previously published in a number of other papers. We now take the research a step further by consolidating the experimental samples with respect to the predicted distribution of grains and pores within the sample mass. We make an original contribution by opening the frame of scale sizes with respect to the technical processes of consolidation. This lets us predict the constitutive elements of the microstructures – approximately equidistant grains and pores. In this paper we define in a practical manner the final target elements for experimental consolidation of real samples. It is the main bridge between a designed microstructure and related characteristics – for example, fractal dimensions and final properties of next-generation fractal microelectronics. Peer-reviewed manuscript: [https://hdl.handle.net/21.15107/rcub_dais_4795]

La/Mn codoped BaTiO 3 ceramics with different La 2 O 3 content, ranging from 0.3 to 1.0 at% La, together with undoped BaTiO 3 ,were investigated regarding their microstructure and dielectric properties. The content of MnO 2 kept constant at 0.01 at% Mn in all investigated samples. La/Mn codoped and undoped BaTiO 3 were obtained by a modified Pechini method and sintered in air at 1300 0 C for two hours. The homogeneous and completely fine-grained microstructure with average grain size from 0.3 to 1mm was observed in samples doped with 0.3 at% La. In high doped samples, apart from the fine grained matrix, the appearance of local area with secondary abnormal grains was observed. The dielectric permittivity and dissipation factor were investigated as a function of frequency and temperature. Dielectric permittivity of doped BaTiO 3 was in the range of 3945 to 12846 and decreases with increase of additive content. The highest value of dielectric constant at room temperature (e r = 12846) and the greatest change at Curie temperature (e r = 17738) were measured in 0.3at% La doped samples. Dissipation factor was range from 0.07 to 0.62 for all investigated samples. The Curie constant (C) and Curie-Weiss temperature (T 0 ) together with critical exponent of nonlinearity (g) were calculated using a Curie-Weiss and modified Curie-Weiss law. The Curie constant increase with increasing dopant content and the highest values were measured in 1.0 La doped samples. The obtained values of g is in the range from 1.04 to 1.53 and pointed out the sharp phase transformation from ferroelectric to paraelectric phase at Curie temperature.

In this paper, we present Tesla's Fountain in ceramics technology reconstruction from basic 3D model, simulation of the engine, light and fluids till the real materialization. As the one of the most important model purposes, we enrich this solution by additional multicolor lights. All of this elements are designed based on Tesla's original patent no. 1,113,716, US patent office, granted Oct,13. In this model we applied ceramics technology based on ceramic materials casting and sintering. At the time when the patent was granted, the metal materials science and technologies were more advanced than the ceramics technology and applications. We performed all materials characteristics analyses and preparation steps based on the one author's patent no. 46121, Serbia patent office, granted 21.12.1991. This is one original two patents solution with complete new over-bridging by the state-of-the-art computer modeling and simulation technology. © 2018 Elsevier Ltd This is the peer-reviewed version of the article: Vuckovic, V., Mitic, V.V., Kocic, L., Arizanovic, B., Paunovic, V., Nikolic, R., 2018. Tesla’s Fountain – Modeling and simulation in ceramics technology. Journal of the European Ceramic Society 38, 3049–3056. [https://doi.org/10.1016/j.jeurceramsoc.2018.01.041]

In the process of predicting materials properties, it is necessary to predict microstructures. This is important for ceramic materials, for the purpose of miniaturization and for a higher level of integration. Although the method of material structure reconstruction is for the first time used on BaTiO3-ceramics by these authors, it can also be used for silicate, refractory and other ceramics, and, for any powder-based material. The reconstruction is based on the grain perimeter fractal analysis and the Richardson method. The main contribution of this paper is establishing the relationship between the electronic properties of BaTiO3-ceramics and its microstructural fractal nature. Similar relations can be used for any ceramics or even any materials. The samples consolidation includes both powder pressing (cold sintering phase) and sintering in a furnace (hot sintering phase). The fractal nature characterization has a very important role from the powder phase up to the final microstructure, through which structures it directly impacts electro-physical and other ceramics properties. Thereby, the new possibilities in the microstructure characterization applications are directly introduced to an engineering system, providing the new solutions related to computer aided support. This creates new industrial production and application possibilities, especially in the process of ceramics material consolidation, now based on microstructural properties, which is providing a basis for “fractal electronics’’ development. © 2018 Elsevier Ltd

With increasing of the world energy crisis, research for new, renewable and alternative energy sources are in growth. The focus is on research areas, sometimes of minor importance and applications, where the different synthesis methods and microstructure properties optimization, performed significant improvement of output materials’ and components’ electro-physical properties, which is important for higher energy efficiency and in the electricity production (batteries and battery systems, fuel cells and hydrogen energy) contribution. Also, the storage tanks capacity improvement, for the energy produced on such way, which is one of the most important development issues in the energy sphere, represents a very promising research and application area. Having in mind, the results achieved in the electrochemical energy sources field, especially electrolyte development, these energy sources, materials fractal nature optimization analysis contribution, have been investigated. Based on materials fractal structure research field, particularly electronic materials, we have performed microstructure influence parameters research in electrochemistry area. We have investigated the Ho2O3 concentration influence (from 0.01wt% to 1wt%) and sintering temperature (from 1320°C to 1380°C), as consolidation parameters, and thus, also open the electrochemical function fractalization door and in the basic thermodynamic parameters the fractal correction introduced. The fractal dimension dependence on additive concentration is also investigated. [Projekat Ministarstva nauke Republike Srbije, br. 172057: Directed synthesis, structure and properties of multifunctional materials]

The electrical resistivity (ρ) of Yb doped BaTiO 3 ceramics in function of temperature is investigated in this article. The concentrations of additive in the BaTiO 3 doped samples were ranged from 0.01 to 1.0 at % Yb. The conventional solid state reaction is used for preparation of initial samples. The samples are sintered at 1320° and 1380°C in air atmosphere for 4 hours. The electrical resistivity is measured in temperature range from 25°C to 170°C at versatile frequencies. To a temperature of 120°C, resistivity slightly increases with increasing of temperature, but above this temperature the resistivity increases rapidly. The electrical resistivity at the room temperature decreases with increasing concentration of Yb and gain the minimum at about 0.5 at% of donor concentration (low doping level). Over 0.5 at%, ρ increases rapidly with increment of donor content (high doping level). Also, the increment of frequency causes decrement of electrical resistivity for a few order of magnitude.

Electroceramics have a wide range of applications and are a subject of extensive research activities in the fields of ion-conductivity (such as batteries and sensors), electrical insulators (substrates and multilayer integrated circuit packages), semiconductors (sensors), and superconductors. Among the electroceramic materials, ferroelectric and piezoelectric nanomaterials are technically the most challenging. They are known for their unique properties, such as high dielectric constant, as well as high piezoelectric constants, and are used in multilayer capacitors or as microwave devices within wireless communication systems. In addition, perovskite ferroelectric nanomaterials show potential for applications related to solar energy conversion and the production of storage memory devices. Ferroelectric films as functional materials are being extensively explored for various microsensor and microactuator applications, some of them being suitable for biomedical engineering. The most widely investigated perovskite ferroelectric and piezoelectric nanomaterials include BaTiO3, SrTiO3, PbZrTiO3 along with suitable dopants and multiferroic oxides, and ZnO. In this review, the main concept of ferroelectricity in perovskite oxides and related nanomaterials is discussed. Fundamentals of ferroelectric nanomaterials, including size effects of ferroelectric nanomaterials properties and phase transitions are summarized. A detailed discussion on the synthesis, fabrication, nanostructure characterization of ferroelectric and piezoelectric nanomaterials such as BaTiO3, SrTiO3, and ZnO is presented. Progress in the research of ferroelectric perovskite oxide in nanometers scale is also highlighted.

The specimens of BaTiO3 doped with 0.01, 0.1 and 0.5wt% of Er2O3 or Ho2O3 used for this investigation were prepared by the conventional solid state reaction. The specimens were sintered at 1350 degrees C in an air atmosphere for 4hours.The grain size and microstructure characteristics for various samples and their phase composition was carried out using a scanning electron microscope SEM equipped with EDS system. SEM analysis of Er/BaTiO3 and Ho/BaTiO3 doped ceramics showed that in samples doped with a low level of rare-earth ions, the grain size ranged from 10-60m, while with the higher dopant concentration the abnormal grain growth is inhibited and the grain size ranged between 2-10m.We also applied the fractal method in microstructure analysis of sintered ceramics especially as influence on dielectric properties of BaTiO3 ceramics. These fractal effects have been used for better understanding of intergranular capacitors.

Artistic colors represent multicomponent mixtures, the main components of which are binders and pigments. This paper presents the characterization of binders and pigments found in artistic colors by using modern analytical techniques and methods. The color samples were obtained from the art gallery 'Serbia' in the City of Niš, with the aim of acquiring the useful information necessary for proper and efficient restauration of the damaged painting named 'The Lamp and the Figurine' by the famous artist Milan Konjović. The characterization of binder materials wasdone by using the IR spectroscopic analysis with the KBr sample preparation method. According to the obtained IR spectra, it was concluded that the binder materials present in the color samples were oil based. In order to determine the pigment composition of the samples, the SEM-EDS method of the scanning electronic microscopy was used. The results showed that the green pigment-mixture of chromium and cobalt oxides and the yellow pigment-cadmium sulfide were the dominant pigments in the color samples. The results of this study were submitted to the gallery's conserver in order to find the most satisfactory restauration of the damaged artwork.

Morphology of ceramics grains and pores as well as Brownian character of particle dynamics inside ceramics specimen contributes to better understanding of the sintering process. BaTiO3-ceramics, studied in this paper, has light fractal form and it is emanated in three aspects. First, the surface of grains, even in starting green body as well as distribution of grains shows fractal behavior. Second, existence of pores and their distribution follow the rules of fractal geometry. Third, movement of particles inside viscous flow underlies the rule of Brownian motion, which is essentially a fractal category. These three elements, each in its domain influence sintering dynamics, and can be described by dimensionless quantitative factors, αs αp and αm, being normalized to the interval [0,1]. Following sintering process, the associate formulae of Frenkel, Scherer and Mackenzie-Shuttleworth are shown from the angle of view of ceramics fractal dimension changing that approaches to 3. Also, it is shown that the energy balance is not violated after applying fractal correction to quasi equilibrium of the energy emanating from surface area reduction ES and energy adopted by viscous flow Ef .[Projekat Ministarstva nauke Republike Srbije, br. 172057: Directed synthesis, structure and properties of multifunctional materials]

The materials based on BaTiO3 can be controlled using different technological parameters and different additives. The influence of different temperature levels of sintering (1320°C, 1350°C and 1380°C) on the size of contact area for 0.1% Ho2O3 doped BaTiO3-ceramics has been investigated. Microstructural investigations were carried out using scanning electron microscopy (JEOL-JSM 5300) equipped with EDS (QX 2000S) system. Grain size distribution was determined by quantitative metallography method. The new correlation between microstructure and dielectric properties of doped BaTiO3-ceramics based on fractal geometry and contact surface probability is recently developed. The presented results indicate that statistical model of contact surfaces is important for the prognosis of BaTiO3-ceramics microstructure and dielectric properties. [Projekat Ministarstva nauke Republike Srbije, br. 172057: Directed synthesis, structure and properties of multifunctional materials i br. III44006]

The Ho doped BaTiO3 ceramics, with different Ho2O3 content, ranging from 0.01 to 1.0 wt % Ho, were investigated regarding their microstructural and dielectric characteristics. Doped BaTiO3 were prepared using conventional solid state reaction and sintered at 1380°C for four hours. SEM analysis of Ho/BaTiO3 doped ceramics showed that the low doped samples exhibit mainly fairly uniform and homogeneous microstructure with the grain size ranged from 20-40 μm. In the samples with the higher dopant concentration the abnormal grain growth is inhibited and the grain size ranged between 2-10 μm. Measurements of dielectric properties were carried out as a function of temperature up to 180 °C at different frequencies. The samples doped with 0.01wt % of Ho, exhibit the high value of dielectric permittivity (εr = 2160) at room temperature. A nearly flat permittivity-response was obtained in specimens with higher additive content. Using a Curie-Weiss law and modified Curie-Weiss law the Curie constant (C), Curie temperature (Tc) and a critical exponent of nonlinearity (g) were calculated. The Curie temperature of doped samples were ranged from 128 to 130°C. The Curie constant for all series of samples decrease with increase of dopant concentration and the lowest values were observed on samples doped with 0.01 wt % of holmium. [Projekat Ministarstva nauke Republike Srbije, br. OI 172057: Directed synthesis, structure and properties of multifunctional materials i br. TR 32026]

In this paper the results of characterization and modeling of passive electronic devices (capacitors and inductors) have been presented. The experimental results obtained using RF impedance analyzer have been discussed, and based on them, parameters of equivalent circuits have been determined using analytical model. Approximate functions for parasitic elements of the devices have been proposed.

In the present study the effect of preparation conditions on microstructure and electrical properties of MgTiO 3 ceramics was investigated. Mixture of MgO and TiO 2 powders was subjected to mechanical activation for different time periods. Two types of sintering (two-step and HIP sintering) were performed on green bodies prepared by cold isostatic pressing. AC impedance spectroscopy in the low-frequency range (from 20 Hz to 1 MHz), at room and elevated temperatures, were performed in order to separate contribution of grains and grain boundaries to capacitance, resistance and conductivity of magnesium titanate ceramics. The special attention was directed to explanation of the influence of mechanical activation on electrical and morphological changes in sintered samples. The significant decrease of partial oxygen pressure in HP sintering atmosphere caused the change from insulating behavior of MgTiO 3 samples after two-step sintering to semiconducting one.

Starting in the last two decades of 20th Century, fractal geometry and underlying analysis became a part of material sciences. From ore distribution in Earth layers to nanotechnology, from biomedical to energy applications, fractal descriptors of physicochemical properties of matter are inevitable part of scientific research and presentations. Fractal and spectral dimensions replace the usual (geometric) dimension, multifractal distributions appear instead convention statistical ones, Weierstrass functions replace standard algebraic or trigonometric polynomials. In the fractal frame of mind, description, construction or reconstruction of fairly complicated and uneven objects such as ceramic grains, ferromagnetic domains or pores labyrinth are as easy as working with ideal Euclidean objects like circles and squares. The aim of this work is to point out the most important issues where powder materials technology, like mass density, particle density, electric charge density, energy density etc., intersects with the notion of fractal dimension and power law equations and other fractal constructions and corresponding applications.

In this study, in order to establish grain shapes of sintered ceramics, new approach on correlation between microstructure and doped BaTiO3 -ceramics properties based, on Voronoi model and mathematical statistics calculations on fractal geometry, has been developed. BaTiO3-ceramics doped with Yb2O3 (from 0.1 to 1.0wt% of Yb) were prepared by using conventional solid state procedure and were sintered from 1320°C to 1380°C for four hours. The microstructure of sintered specimens was investigated by Scanning electron microscope JEOL-SEM-5300. For better and deeper characterization and understanding of the ceramics material microstructure, the methods which include the fractal nature structure, and also Voronoi model and mathematical statistics calculations, are applied. In our research the Voronoi is one specific interface between fractal structure nature and different stochastically contact surfaces, defined by statistical mathematical methods. Also, the Voronoi model practically provided possibility to control the ceramics microstructure fractal nature. Mathematical statistic methods enabled establishing the real model for the prognosis based on correlation: synthesis-structures-properties. [Projekat Ministarstva nauke Republike Srbije, br. 172057 i br. III44006]

Metal-endings are integral part of different ultrasonic sandwich transducers. In this paper a new Matlab/Simulink 3D model of the finite metal rings and discs of various dimensions is realized. With this model, which describes both the thickness and the radial resonant modes, and the coupling between them, mechanical impedance of the sample can be easily computed. Resonance frequency-length curves for rings and disks with various materials and for different selected dimensions are given. Also, comparisons of the different approaches in determining of their resonant frequencies are shown. The proposed Matlab/Simulink model requires simpler implementation than other analytical models. That enabled modifying of 1D theory and simplified modelling and projecting of the ultrasonic sandwich transducers with short-endings. Finally, the computed and experimental results are compared. [Projekat Ministarstva nauke Republike Srbije, br. TR33035, br. III43014 i br. OI172057]

Sintering process is a complex of different synergetic effects during the ceramics materials consolidation. The microstructural level properties control is very important as a stage in advanced materials prognosis. SEM analysis of Yb/BaTiO3 doped ceramics showed that in samples doped with a low level of dopant and sintered at higher temperatures the grain size ranged from 10-60?m, while with the higher dopant concentration the grain size ranged between 2-15?m. The morphology of sintered BaTiO3-ceramics grains points out the validity of developing new structure analytical methods based on different geometries of grains' model systems. The idea of electrical properties of BaTiO3-ceramics being influenced by intergrain microcontacts can be successfully followed if we start with the two-sphere Coble?s model and also the correction of the Coble?s model. In this paper, the grains contact models based on spherical, ellipsoidal and polyhedral geometries are presented making a new modeling tool for structure research of BaTiO3-ceramics materials. Intergranular impedance analysis of grains clusters was also introduced. Obtained results enabled establishment of interrelation between structural and electrical parameters.

Kaolinite and bentonite clay powders mixed with active additives, based on Mg(NO3)2 and Al(NO3)2, sintered at high temperatures produce very porous ceramics with microcrystalline and amorphous regions and highly developed metalized surfaces (mainly with magnesium surplus). Microstructure investigations have revealed non-uniform and highly porous structure with broad distribution of grain size, specifically shaped grains and high degree of agglomeration. The ceramics samples were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction analysis (XRD) and IR spectroscopy analysis, prior and after treatment in ?synthetic water?, i.e. in aqueous solution of arsenic-salt. Grain size distribution for untreated and treated samples was done with software SemAfore 4. It has shown great variety in size distribution of grains from clay powders to sintered samples.

La/Mn codoped BaTiO3 with different La2O3 content, ranging from 0.1 to 5.0 at% La, was investigated regarding their microstructural and dielectric characteristics. The content of 0.05 at% Mn was constant in all investigated samples. The samples were sintered at 1320?C and 1350?C for two hours. Microstructural studies were done using SEM and EDS analysis. The fine-grained microstructure was obtained even for low content of La. The appearance of secondary abnormal grains with serrated features along grain boundaries was observed in 1.0 at% La-BaTiO3 sintered at 1350?C. Nearly flat permittivity-temperature response was obtained in specimens with 2.0 and 5.0 at% La. Using the modified Curie-Weiss law a critical exponent ? and C' were calculated. The obtained values of ? pointed out the diffuse phase transformation in heavily doped BaTiO3 and great departure from the Curie-Weiss law for low doped ceramics.