TY  - JOUR
AU  - Kosanović, Darko
AU  - Blagojević, Vladimir A.
AU  - Labus, Nebojša
AU  - Tadić, N.B.
AU  - Pavlović, Vladimir
AU  - Ristić, M.M.
PY  - 2018
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/4724
AB  - Barium strontium titanate powders with different Ba: Sr ratios were investigated to determine the influence of the initial composition of powder mixture on microstructural properties and sintering kinetics. It was determined that BaCO3 and SrCO3 react differently to mixing, resulting in Ba0.5Sr0.5CO3 in the sample with 80% Ba and different contents of Ba1-xSrxTiO3 in samples with 50% and 20% Ba. In addition, the morphology is also different, with higher Sr content leading to larger particles size and less agglomeration. The different chemical content of the initial powder mixture also has a marked impact on the sintering process: the onset of sintering shifts towards higher temperature with higher Sr content, while the average apparent activation energy of sintering is the highest for the sample with 80% Ba and the lowest for the mixture with 50% Ba. In addition, hexagonal-to-cubic phase transformation was observed in parallel with the sintering process, where the position of the phase transition shifts to lower temperatures with an increase in Sr content. This is consistent with the behavior of low-temperature phase transitions of BST. The phase transition was not observed in sintered samples, suggesting that there is a size-dependence of the phase transition temperature.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Effect of Chemical Composition on Microstructural Properties and Sintering Kinetics of (Ba,Sr) TiO3 Powders
EP  - 38
IS  - 1
SP  - 29
VL  - 50
DO  - 10.2298/SOS1801029K
ER  - 

@article{
author = "Kosanović, Darko and Blagojević, Vladimir A. and Labus, Nebojša and Tadić, N.B. and Pavlović, Vladimir and Ristić, M.M.",
year = "2018",
abstract = "Barium strontium titanate powders with different Ba: Sr ratios were investigated to determine the influence of the initial composition of powder mixture on microstructural properties and sintering kinetics. It was determined that BaCO3 and SrCO3 react differently to mixing, resulting in Ba0.5Sr0.5CO3 in the sample with 80% Ba and different contents of Ba1-xSrxTiO3 in samples with 50% and 20% Ba. In addition, the morphology is also different, with higher Sr content leading to larger particles size and less agglomeration. The different chemical content of the initial powder mixture also has a marked impact on the sintering process: the onset of sintering shifts towards higher temperature with higher Sr content, while the average apparent activation energy of sintering is the highest for the sample with 80% Ba and the lowest for the mixture with 50% Ba. In addition, hexagonal-to-cubic phase transformation was observed in parallel with the sintering process, where the position of the phase transition shifts to lower temperatures with an increase in Sr content. This is consistent with the behavior of low-temperature phase transitions of BST. The phase transition was not observed in sintered samples, suggesting that there is a size-dependence of the phase transition temperature.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Effect of Chemical Composition on Microstructural Properties and Sintering Kinetics of (Ba,Sr) TiO3 Powders",
pages = "38-29",
number = "1",
volume = "50",
doi = "10.2298/SOS1801029K"
}

Kosanović, D., Blagojević, V. A., Labus, N., Tadić, N.B., Pavlović, V.,& Ristić, M.M.. (2018). Effect of Chemical Composition on Microstructural Properties and Sintering Kinetics of (Ba,Sr) TiO3 Powders. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 50(1), 29-38.
https://doi.org/10.2298/SOS1801029K

Kosanović D, Blagojević VA, Labus N, Tadić N, Pavlović V, Ristić M. Effect of Chemical Composition on Microstructural Properties and Sintering Kinetics of (Ba,Sr) TiO3 Powders. in Science of Sintering. 2018;50(1):29-38.
doi:10.2298/SOS1801029K .

Kosanović, Darko, Blagojević, Vladimir A., Labus, Nebojša, Tadić, N.B., Pavlović, Vladimir, Ristić, M.M., "Effect of Chemical Composition on Microstructural Properties and Sintering Kinetics of (Ba,Sr) TiO3 Powders" in Science of Sintering, 50, no. 1 (2018):29-38,
https://doi.org/10.2298/SOS1801029K . .

TY  - JOUR
AU  - Kosanović, Darko
AU  - Obradović, N.
AU  - Pavlović, Vera P.
AU  - Marković, S.
AU  - Maricić, A.
AU  - Rasić, G.
AU  - Vlahović, Branislav
AU  - Pavlović, Vladimir
AU  - Ristić, M.M.
PY  - 2016
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/4010
AB  - Crystal structure and morphology of mechanically activated nanocrystalline Fe/BaTiO3 was investigated using a combination of spectroscopic and microscopic methods. These show that mechanical activation led to the creation of new surfaces and the comminution of the initial powder particles. Prolonged milling resulted in formation of larger agglomerates of BaTiO3 and bimodal particle size distribution, where BaTiO3 particles were significantly larger than those of iron-containing phases. Milling times of 210 min and above lead to a significant decrease in temperature of the oxidation of iron in the sample, indicating abrupt change in reactivity. Raman spectroscopy analysis has revealed that activation had a pronounced influence on Fe/BaTiO3 lattice, thereby affecting both the stability of the crystal structure and the phase transition phenomena.
PB  - Elsevier, Amsterdam
T2  - Materials Science and Engineering B-Advanced Functional Solid-State Materials
T1  - The influence of mechanical activation on the morphological changes of Fe/BaTiO3 powder
EP  - 95
SP  - 89
VL  - 212
DO  - 10.1016/j.mseb.2016.07.016
ER  - 

@article{
author = "Kosanović, Darko and Obradović, N. and Pavlović, Vera P. and Marković, S. and Maricić, A. and Rasić, G. and Vlahović, Branislav and Pavlović, Vladimir and Ristić, M.M.",
year = "2016",
abstract = "Crystal structure and morphology of mechanically activated nanocrystalline Fe/BaTiO3 was investigated using a combination of spectroscopic and microscopic methods. These show that mechanical activation led to the creation of new surfaces and the comminution of the initial powder particles. Prolonged milling resulted in formation of larger agglomerates of BaTiO3 and bimodal particle size distribution, where BaTiO3 particles were significantly larger than those of iron-containing phases. Milling times of 210 min and above lead to a significant decrease in temperature of the oxidation of iron in the sample, indicating abrupt change in reactivity. Raman spectroscopy analysis has revealed that activation had a pronounced influence on Fe/BaTiO3 lattice, thereby affecting both the stability of the crystal structure and the phase transition phenomena.",
publisher = "Elsevier, Amsterdam",
journal = "Materials Science and Engineering B-Advanced Functional Solid-State Materials",
title = "The influence of mechanical activation on the morphological changes of Fe/BaTiO3 powder",
pages = "95-89",
volume = "212",
doi = "10.1016/j.mseb.2016.07.016"
}

Kosanović, D., Obradović, N., Pavlović, V. P., Marković, S., Maricić, A., Rasić, G., Vlahović, B., Pavlović, V.,& Ristić, M.M.. (2016). The influence of mechanical activation on the morphological changes of Fe/BaTiO3 powder. in Materials Science and Engineering B-Advanced Functional Solid-State Materials
Elsevier, Amsterdam., 212, 89-95.
https://doi.org/10.1016/j.mseb.2016.07.016

Kosanović D, Obradović N, Pavlović VP, Marković S, Maricić A, Rasić G, Vlahović B, Pavlović V, Ristić M. The influence of mechanical activation on the morphological changes of Fe/BaTiO3 powder. in Materials Science and Engineering B-Advanced Functional Solid-State Materials. 2016;212:89-95.
doi:10.1016/j.mseb.2016.07.016 .

Kosanović, Darko, Obradović, N., Pavlović, Vera P., Marković, S., Maricić, A., Rasić, G., Vlahović, Branislav, Pavlović, Vladimir, Ristić, M.M., "The influence of mechanical activation on the morphological changes of Fe/BaTiO3 powder" in Materials Science and Engineering B-Advanced Functional Solid-State Materials, 212 (2016):89-95,
https://doi.org/10.1016/j.mseb.2016.07.016 . .

TY  - JOUR
AU  - Kosanović, Darko
AU  - Zivojinović, J.
AU  - Obradović, N.
AU  - Pavlović, Vera P.
AU  - Pavlović, Vladimir
AU  - Peles, A.
AU  - Ristić, M.M.
PY  - 2014
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3418
AB  - Ferroelectric barium strontium titanate (Ba0.77Sr0.23TiO3), BST, was prepared by solid-state reactions using as the starting compounds powder of barium carbonate (BaCO3), strontium carbonate (SrCO3) and titanium dioxide (TiO2 anatase). Non-activated mixtures and mixtures mechanically activated in a high-energy planetary ball mill (0, 5, 10, 20, 40, 80 and 120 min) were sintered at 1100, 1200, 1300 and 1400 degrees C for 2 h in air atmosphere. Defects and the effect of the beginning of the sintering process on the microstructure were investigated by scanning electron microscopy (SEM). Electrical measurements (loss tangent and resistivity as the function of frequency X-C =f(log nu)) were performed for ceramics sintered at 1400 degrees C for 2 h. It has been found that mechanical activation can reduce the sintering temperature by around 100 degrees C, which leads to significant energy savings. Furthermore, activated for 80 min and sintered at. 1400 degrees C for 2 h exhibit the largest density values and have about 36% lower dielectric loss at a frequency of 1 kHz and about 57% at a frequency of 10 kHz than the samples obtained from the initial non-activated powder sintered under the same conditions.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - The influence of mechanical activation on the electrical properties of Ba0.77Sr0.23TiO3 ceramics
EP  - 11888
IS  - 8
SP  - 11883
VL  - 40
DO  - 10.1016/j.ceramint.2014.04.023
ER  - 

@article{
author = "Kosanović, Darko and Zivojinović, J. and Obradović, N. and Pavlović, Vera P. and Pavlović, Vladimir and Peles, A. and Ristić, M.M.",
year = "2014",
abstract = "Ferroelectric barium strontium titanate (Ba0.77Sr0.23TiO3), BST, was prepared by solid-state reactions using as the starting compounds powder of barium carbonate (BaCO3), strontium carbonate (SrCO3) and titanium dioxide (TiO2 anatase). Non-activated mixtures and mixtures mechanically activated in a high-energy planetary ball mill (0, 5, 10, 20, 40, 80 and 120 min) were sintered at 1100, 1200, 1300 and 1400 degrees C for 2 h in air atmosphere. Defects and the effect of the beginning of the sintering process on the microstructure were investigated by scanning electron microscopy (SEM). Electrical measurements (loss tangent and resistivity as the function of frequency X-C =f(log nu)) were performed for ceramics sintered at 1400 degrees C for 2 h. It has been found that mechanical activation can reduce the sintering temperature by around 100 degrees C, which leads to significant energy savings. Furthermore, activated for 80 min and sintered at. 1400 degrees C for 2 h exhibit the largest density values and have about 36% lower dielectric loss at a frequency of 1 kHz and about 57% at a frequency of 10 kHz than the samples obtained from the initial non-activated powder sintered under the same conditions.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "The influence of mechanical activation on the electrical properties of Ba0.77Sr0.23TiO3 ceramics",
pages = "11888-11883",
number = "8",
volume = "40",
doi = "10.1016/j.ceramint.2014.04.023"
}

Kosanović, D., Zivojinović, J., Obradović, N., Pavlović, V. P., Pavlović, V., Peles, A.,& Ristić, M.M.. (2014). The influence of mechanical activation on the electrical properties of Ba0.77Sr0.23TiO3 ceramics. in Ceramics International
Elsevier Sci Ltd, Oxford., 40(8), 11883-11888.
https://doi.org/10.1016/j.ceramint.2014.04.023

Kosanović D, Zivojinović J, Obradović N, Pavlović VP, Pavlović V, Peles A, Ristić M. The influence of mechanical activation on the electrical properties of Ba0.77Sr0.23TiO3 ceramics. in Ceramics International. 2014;40(8):11883-11888.
doi:10.1016/j.ceramint.2014.04.023 .

Kosanović, Darko, Zivojinović, J., Obradović, N., Pavlović, Vera P., Pavlović, Vladimir, Peles, A., Ristić, M.M., "The influence of mechanical activation on the electrical properties of Ba0.77Sr0.23TiO3 ceramics" in Ceramics International, 40, no. 8 (2014):11883-11888,
https://doi.org/10.1016/j.ceramint.2014.04.023 . .

TY  - JOUR
AU  - Filipović, Suzana
AU  - Obradović, N.
AU  - Krstić, J.
AU  - Scepanović, M.
AU  - Pavlović, Vladimir
AU  - Paunović, V.
AU  - Ristić, M.M.
PY  - 2013
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3296
AB  - In this article the influence of ball miling process on structure of MgO-TiO2 system, as well as the electrical properties of samples after sintering, was investigated. The mixtures of MgO-TiO2 powders were mechanically activated in a planetary ball mill for the time period from 0 to 120 min. The influence of mechanical activation and sintering on the lattice vibrational spectra was studied by Raman spectroscopy at room temperature. Structural investigations have been performed on produced powders. Nitrogen adsorption method was used to determine the BET specific surface area and pore size distribution. Unusual results have been obtained: specific surface area continuosly decreased up to 40 min of activation and increased after that, reaching its minimun value of 5.5 m(2)/g. The Raman spectra of activated powders have shown that anatase modes have been decreasing in intensity and broadening as the time of activation extended. Also, the additional modes attributed to TiO2 II, srilankite and rutile phases started to appear as a consequence of activation. The small differences noticed in the Raman spectra of sintered samples have been explained by structural modification of MgTiO3 phase due to the presence of defects. The effects of activation and sintering process on microstructure were investigated by scanning electron microscopy (SEM). The electrical measurements showed difference in dielectric constant (epsilon(r)), loss tangent (tg delta) and specific resistance (rho) as a function of time of mechanical treatment.
PB  - Elsevier Science Sa, Lausanne
T2  - Journal of Alloys and Compounds
T1  - Structural characterization and electrical properties of sintered magnesium-titanate ceramics
EP  - 44
SP  - 39
VL  - 555
DO  - 10.1016/j.jallcom.2012.12.040
ER  - 

@article{
author = "Filipović, Suzana and Obradović, N. and Krstić, J. and Scepanović, M. and Pavlović, Vladimir and Paunović, V. and Ristić, M.M.",
year = "2013",
abstract = "In this article the influence of ball miling process on structure of MgO-TiO2 system, as well as the electrical properties of samples after sintering, was investigated. The mixtures of MgO-TiO2 powders were mechanically activated in a planetary ball mill for the time period from 0 to 120 min. The influence of mechanical activation and sintering on the lattice vibrational spectra was studied by Raman spectroscopy at room temperature. Structural investigations have been performed on produced powders. Nitrogen adsorption method was used to determine the BET specific surface area and pore size distribution. Unusual results have been obtained: specific surface area continuosly decreased up to 40 min of activation and increased after that, reaching its minimun value of 5.5 m(2)/g. The Raman spectra of activated powders have shown that anatase modes have been decreasing in intensity and broadening as the time of activation extended. Also, the additional modes attributed to TiO2 II, srilankite and rutile phases started to appear as a consequence of activation. The small differences noticed in the Raman spectra of sintered samples have been explained by structural modification of MgTiO3 phase due to the presence of defects. The effects of activation and sintering process on microstructure were investigated by scanning electron microscopy (SEM). The electrical measurements showed difference in dielectric constant (epsilon(r)), loss tangent (tg delta) and specific resistance (rho) as a function of time of mechanical treatment.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Journal of Alloys and Compounds",
title = "Structural characterization and electrical properties of sintered magnesium-titanate ceramics",
pages = "44-39",
volume = "555",
doi = "10.1016/j.jallcom.2012.12.040"
}

Filipović, S., Obradović, N., Krstić, J., Scepanović, M., Pavlović, V., Paunović, V.,& Ristić, M.M.. (2013). Structural characterization and electrical properties of sintered magnesium-titanate ceramics. in Journal of Alloys and Compounds
Elsevier Science Sa, Lausanne., 555, 39-44.
https://doi.org/10.1016/j.jallcom.2012.12.040

Filipović S, Obradović N, Krstić J, Scepanović M, Pavlović V, Paunović V, Ristić M. Structural characterization and electrical properties of sintered magnesium-titanate ceramics. in Journal of Alloys and Compounds. 2013;555:39-44.
doi:10.1016/j.jallcom.2012.12.040 .

Filipović, Suzana, Obradović, N., Krstić, J., Scepanović, M., Pavlović, Vladimir, Paunović, V., Ristić, M.M., "Structural characterization and electrical properties of sintered magnesium-titanate ceramics" in Journal of Alloys and Compounds, 555 (2013):39-44,
https://doi.org/10.1016/j.jallcom.2012.12.040 . .

TY  - JOUR
AU  - Terzić, Anja
AU  - Pavlović, Ljubica
AU  - Obradović, N.
AU  - Pavlović, Vladimir
AU  - Stojanović, J.
AU  - Milicić, Lj.
AU  - Radojević, Z.
AU  - Ristić, M.M.
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3064
AB  - Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature application (thermal insulators or/and refractory material products). As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by applying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Synthesis and Sintering of High-temperature Composites Based on Mechanically Activated Fly Ash
EP  - 146
IS  - 2
SP  - 135
VL  - 44
DO  - 10.2298/SOS1202135T
ER  - 

@article{
author = "Terzić, Anja and Pavlović, Ljubica and Obradović, N. and Pavlović, Vladimir and Stojanović, J. and Milicić, Lj. and Radojević, Z. and Ristić, M.M.",
year = "2012",
abstract = "Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature application (thermal insulators or/and refractory material products). As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by applying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Synthesis and Sintering of High-temperature Composites Based on Mechanically Activated Fly Ash",
pages = "146-135",
number = "2",
volume = "44",
doi = "10.2298/SOS1202135T"
}

Terzić, A., Pavlović, L., Obradović, N., Pavlović, V., Stojanović, J., Milicić, Lj., Radojević, Z.,& Ristić, M.M.. (2012). Synthesis and Sintering of High-temperature Composites Based on Mechanically Activated Fly Ash. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 44(2), 135-146.
https://doi.org/10.2298/SOS1202135T

Terzić A, Pavlović L, Obradović N, Pavlović V, Stojanović J, Milicić L, Radojević Z, Ristić M. Synthesis and Sintering of High-temperature Composites Based on Mechanically Activated Fly Ash. in Science of Sintering. 2012;44(2):135-146.
doi:10.2298/SOS1202135T .

Terzić, Anja, Pavlović, Ljubica, Obradović, N., Pavlović, Vladimir, Stojanović, J., Milicić, Lj., Radojević, Z., Ristić, M.M., "Synthesis and Sintering of High-temperature Composites Based on Mechanically Activated Fly Ash" in Science of Sintering, 44, no. 2 (2012):135-146,
https://doi.org/10.2298/SOS1202135T . .

TY  - JOUR
AU  - Obradović, N.
AU  - Filipović, Suzana
AU  - Mitrić, M.
AU  - Pavlović, Vladimir
AU  - Paunović, V.
AU  - Kosanović, Darko
AU  - Balac, I.
AU  - Ristić, M.M.
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3015
AB  - Starting mixtures of BaCO3, ZnO, and TiO2 powders are mechanically activated in a planetary ball mill for various periods of time. The powders obtained are sintered isothermally at 1100A degrees C for 120 min. Non-isothermal sintering process is followed by measurements with a sensitive dilatometer, as well. Results of microstructure characterization using SEM analyses along with DTA analyses are provided. These results are correlated with the values of electric resistivity, capacitance, and loss tangent of the samples, and it is found that with increasing milling time, the increase in values of electrical properties is noticed.
PB  - Springer, New York
T2  - Powder Metallurgy and Metal Ceramics
T1  - Influence of mechanical activation on electrical properties of barium-zinc-titanate ceramics sintered at 1100A degrees C
EP  - 718
IS  - 11-12
SP  - 714
VL  - 50
DO  - 10.1007/s11106-012-9380-y
ER  - 

@article{
author = "Obradović, N. and Filipović, Suzana and Mitrić, M. and Pavlović, Vladimir and Paunović, V. and Kosanović, Darko and Balac, I. and Ristić, M.M.",
year = "2012",
abstract = "Starting mixtures of BaCO3, ZnO, and TiO2 powders are mechanically activated in a planetary ball mill for various periods of time. The powders obtained are sintered isothermally at 1100A degrees C for 120 min. Non-isothermal sintering process is followed by measurements with a sensitive dilatometer, as well. Results of microstructure characterization using SEM analyses along with DTA analyses are provided. These results are correlated with the values of electric resistivity, capacitance, and loss tangent of the samples, and it is found that with increasing milling time, the increase in values of electrical properties is noticed.",
publisher = "Springer, New York",
journal = "Powder Metallurgy and Metal Ceramics",
title = "Influence of mechanical activation on electrical properties of barium-zinc-titanate ceramics sintered at 1100A degrees C",
pages = "718-714",
number = "11-12",
volume = "50",
doi = "10.1007/s11106-012-9380-y"
}

Obradović, N., Filipović, S., Mitrić, M., Pavlović, V., Paunović, V., Kosanović, D., Balac, I.,& Ristić, M.M.. (2012). Influence of mechanical activation on electrical properties of barium-zinc-titanate ceramics sintered at 1100A degrees C. in Powder Metallurgy and Metal Ceramics
Springer, New York., 50(11-12), 714-718.
https://doi.org/10.1007/s11106-012-9380-y

Obradović N, Filipović S, Mitrić M, Pavlović V, Paunović V, Kosanović D, Balac I, Ristić M. Influence of mechanical activation on electrical properties of barium-zinc-titanate ceramics sintered at 1100A degrees C. in Powder Metallurgy and Metal Ceramics. 2012;50(11-12):714-718.
doi:10.1007/s11106-012-9380-y .

Obradović, N., Filipović, Suzana, Mitrić, M., Pavlović, Vladimir, Paunović, V., Kosanović, Darko, Balac, I., Ristić, M.M., "Influence of mechanical activation on electrical properties of barium-zinc-titanate ceramics sintered at 1100A degrees C" in Powder Metallurgy and Metal Ceramics, 50, no. 11-12 (2012):714-718,
https://doi.org/10.1007/s11106-012-9380-y . .

TY  - JOUR
AU  - Kosanović, Darko
AU  - Obradović, N.
AU  - Zivojinović, J.
AU  - Filipović, Suzana
AU  - Maricić, A.
AU  - Pavlović, Vladimir
AU  - Tang, Y.
AU  - Ristić, M.M.
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3040
AB  - 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.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Mechanical-Chemical Synthesis Ba0.77Sr0.23TiO3
EP  - 55
IS  - 1
SP  - 47
VL  - 44
DO  - 10.2298/SOS1201047K
ER  - 

@article{
author = "Kosanović, Darko and Obradović, N. and Zivojinović, J. and Filipović, Suzana and Maricić, A. and Pavlović, Vladimir and Tang, Y. and Ristić, M.M.",
year = "2012",
abstract = "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.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Mechanical-Chemical Synthesis Ba0.77Sr0.23TiO3",
pages = "55-47",
number = "1",
volume = "44",
doi = "10.2298/SOS1201047K"
}

Kosanović, D., Obradović, N., Zivojinović, J., Filipović, S., Maricić, A., Pavlović, V., Tang, Y.,& Ristić, M.M.. (2012). Mechanical-Chemical Synthesis Ba0.77Sr0.23TiO3. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 44(1), 47-55.
https://doi.org/10.2298/SOS1201047K

Kosanović D, Obradović N, Zivojinović J, Filipović S, Maricić A, Pavlović V, Tang Y, Ristić M. Mechanical-Chemical Synthesis Ba0.77Sr0.23TiO3. in Science of Sintering. 2012;44(1):47-55.
doi:10.2298/SOS1201047K .

Kosanović, Darko, Obradović, N., Zivojinović, J., Filipović, Suzana, Maricić, A., Pavlović, Vladimir, Tang, Y., Ristić, M.M., "Mechanical-Chemical Synthesis Ba0.77Sr0.23TiO3" in Science of Sintering, 44, no. 1 (2012):47-55,
https://doi.org/10.2298/SOS1201047K . .

TY  - JOUR
AU  - Obradović, N.
AU  - Nikolić, M.V.
AU  - Nikolić, N.
AU  - Filipović, Suzana
AU  - Mitrić, M.
AU  - Pavlović, Vladimir
AU  - Nikolić, P.M.
AU  - Djordjević, Antonije
AU  - Ristić, M.M.
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3052
AB  - Mixtures of BaCO3, ZnO and TiO2 powders, with molar ratio of 1:2:4, were mechanically activated for 20, 40 and minutes in a planetary ball mill. The resulting powders were compacted into pellets and isothermally sintered at 1250 degrees C for 2h with a heating rate of 10 degrees C/min. X-ray diffraction analysis of obtained powders and sintered samples was performed in order to investigate changes of the phase composition. The microstructure of sintered samples was examined by scanning electron microscopy. The photoacoustic phase and amplitude spectra of sintered samples were measured as a function of the laser beam modulating frequency using a transmission detection configuration. Fitting of experimental data enabled determination of photoacoustic properties including thermal diffusivity. Based on the results obtained correlation between thermal diffusivity and experimental conditions, as well the samples microstructure characteristics, was discussed.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Synthesis of Barium-zinc-titanate Ceramics
EP  - 71
IS  - 1
SP  - 65
VL  - 44
DO  - 10.2298/SOS1201065O
ER  - 

@article{
author = "Obradović, N. and Nikolić, M.V. and Nikolić, N. and Filipović, Suzana and Mitrić, M. and Pavlović, Vladimir and Nikolić, P.M. and Djordjević, Antonije and Ristić, M.M.",
year = "2012",
abstract = "Mixtures of BaCO3, ZnO and TiO2 powders, with molar ratio of 1:2:4, were mechanically activated for 20, 40 and minutes in a planetary ball mill. The resulting powders were compacted into pellets and isothermally sintered at 1250 degrees C for 2h with a heating rate of 10 degrees C/min. X-ray diffraction analysis of obtained powders and sintered samples was performed in order to investigate changes of the phase composition. The microstructure of sintered samples was examined by scanning electron microscopy. The photoacoustic phase and amplitude spectra of sintered samples were measured as a function of the laser beam modulating frequency using a transmission detection configuration. Fitting of experimental data enabled determination of photoacoustic properties including thermal diffusivity. Based on the results obtained correlation between thermal diffusivity and experimental conditions, as well the samples microstructure characteristics, was discussed.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Synthesis of Barium-zinc-titanate Ceramics",
pages = "71-65",
number = "1",
volume = "44",
doi = "10.2298/SOS1201065O"
}

Obradović, N., Nikolić, M.V., Nikolić, N., Filipović, S., Mitrić, M., Pavlović, V., Nikolić, P.M., Djordjević, A.,& Ristić, M.M.. (2012). Synthesis of Barium-zinc-titanate Ceramics. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 44(1), 65-71.
https://doi.org/10.2298/SOS1201065O

Obradović N, Nikolić M, Nikolić N, Filipović S, Mitrić M, Pavlović V, Nikolić P, Djordjević A, Ristić M. Synthesis of Barium-zinc-titanate Ceramics. in Science of Sintering. 2012;44(1):65-71.
doi:10.2298/SOS1201065O .

Obradović, N., Nikolić, M.V., Nikolić, N., Filipović, Suzana, Mitrić, M., Pavlović, Vladimir, Nikolić, P.M., Djordjević, Antonije, Ristić, M.M., "Synthesis of Barium-zinc-titanate Ceramics" in Science of Sintering, 44, no. 1 (2012):65-71,
https://doi.org/10.2298/SOS1201065O . .

TY  - JOUR
AU  - Kosanović, Darko
AU  - Obradović, N.
AU  - Zivojinović, J.
AU  - Maricić, A.
AU  - Pavlović, Vera P.
AU  - Pavlović, Vladimir
AU  - Ristić, M.M.
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3050
AB  - In this article the influence of mechanical activation on sintering process of barium-strontium-titanate ceramics has been investigated. Both non-activated and mixtures treated in a planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400 degrees C for 2 hours in presence of air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100 degrees C was too low to induce final sintering stage for this system. Electrical measurements have been conducted for the densest ceramics sintered at 1400 degrees C for 2 hours.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - The Influence of Mechanical Activation on Sintering Process of BaCO3-SrCO3-TiO2 System
EP  - 280
IS  - 3
SP  - 271
VL  - 44
DO  - 10.2298/SOS1203271K
ER  - 

@article{
author = "Kosanović, Darko and Obradović, N. and Zivojinović, J. and Maricić, A. and Pavlović, Vera P. and Pavlović, Vladimir and Ristić, M.M.",
year = "2012",
abstract = "In this article the influence of mechanical activation on sintering process of barium-strontium-titanate ceramics has been investigated. Both non-activated and mixtures treated in a planetary ball mill for 5, 10, 20, 40, 80 and 120 minutes were sintered at 1100-1400 degrees C for 2 hours in presence of air atmosphere. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100 degrees C was too low to induce final sintering stage for this system. Electrical measurements have been conducted for the densest ceramics sintered at 1400 degrees C for 2 hours.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "The Influence of Mechanical Activation on Sintering Process of BaCO3-SrCO3-TiO2 System",
pages = "280-271",
number = "3",
volume = "44",
doi = "10.2298/SOS1203271K"
}

Kosanović, D., Obradović, N., Zivojinović, J., Maricić, A., Pavlović, V. P., Pavlović, V.,& Ristić, M.M.. (2012). The Influence of Mechanical Activation on Sintering Process of BaCO3-SrCO3-TiO2 System. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 44(3), 271-280.
https://doi.org/10.2298/SOS1203271K

Kosanović D, Obradović N, Zivojinović J, Maricić A, Pavlović VP, Pavlović V, Ristić M. The Influence of Mechanical Activation on Sintering Process of BaCO3-SrCO3-TiO2 System. in Science of Sintering. 2012;44(3):271-280.
doi:10.2298/SOS1203271K .

Kosanović, Darko, Obradović, N., Zivojinović, J., Maricić, A., Pavlović, Vera P., Pavlović, Vladimir, Ristić, M.M., "The Influence of Mechanical Activation on Sintering Process of BaCO3-SrCO3-TiO2 System" in Science of Sintering, 44, no. 3 (2012):271-280,
https://doi.org/10.2298/SOS1203271K . .

TY  - JOUR
AU  - Obradović, N.
AU  - Filipović, Suzana
AU  - Pavlović, Vladimir
AU  - Paunović, V.
AU  - Mitrić, M.
AU  - Ristić, M.M.
PY  - 2011
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2643
AB  - The aim of this work was an investigation of structural and electrical properties of sintered barium-zinc-titanate ceramics. Mixtures of BaCO3, ZnO and TiO2 were mechanically activated in a planetary ball mill up to 80 minutes and sintered isothermally in air for 120 minutes at 1300 degrees C. The phase composition in the BaCO3-ZnO-TiO2 system after milling and sintering was analyzed using the XRD method. The existence of pure barium-zinc-titanate has been registered. Microstructure analyses were performed using SEM. The results of electric resistivity, capacitance and loss tangent of the sintered samples were correlated with the XRD and SEM results.
PB  - Polish Acad Sciences Inst Physics, Warsaw
T2  - Acta Physica Polonica A
T1  - Structural and Electrical Properties of Sintered Barium-Zinc-Titanate Ceramics
EP  - 325
IS  - 2
SP  - 322
VL  - 120
DO  - 10.12693/APhysPolA.120.322
ER  - 

@article{
author = "Obradović, N. and Filipović, Suzana and Pavlović, Vladimir and Paunović, V. and Mitrić, M. and Ristić, M.M.",
year = "2011",
abstract = "The aim of this work was an investigation of structural and electrical properties of sintered barium-zinc-titanate ceramics. Mixtures of BaCO3, ZnO and TiO2 were mechanically activated in a planetary ball mill up to 80 minutes and sintered isothermally in air for 120 minutes at 1300 degrees C. The phase composition in the BaCO3-ZnO-TiO2 system after milling and sintering was analyzed using the XRD method. The existence of pure barium-zinc-titanate has been registered. Microstructure analyses were performed using SEM. The results of electric resistivity, capacitance and loss tangent of the sintered samples were correlated with the XRD and SEM results.",
publisher = "Polish Acad Sciences Inst Physics, Warsaw",
journal = "Acta Physica Polonica A",
title = "Structural and Electrical Properties of Sintered Barium-Zinc-Titanate Ceramics",
pages = "325-322",
number = "2",
volume = "120",
doi = "10.12693/APhysPolA.120.322"
}

Obradović, N., Filipović, S., Pavlović, V., Paunović, V., Mitrić, M.,& Ristić, M.M.. (2011). Structural and Electrical Properties of Sintered Barium-Zinc-Titanate Ceramics. in Acta Physica Polonica A
Polish Acad Sciences Inst Physics, Warsaw., 120(2), 322-325.
https://doi.org/10.12693/APhysPolA.120.322

Obradović N, Filipović S, Pavlović V, Paunović V, Mitrić M, Ristić M. Structural and Electrical Properties of Sintered Barium-Zinc-Titanate Ceramics. in Acta Physica Polonica A. 2011;120(2):322-325.
doi:10.12693/APhysPolA.120.322 .

Obradović, N., Filipović, Suzana, Pavlović, Vladimir, Paunović, V., Mitrić, M., Ristić, M.M., "Structural and Electrical Properties of Sintered Barium-Zinc-Titanate Ceramics" in Acta Physica Polonica A, 120, no. 2 (2011):322-325,
https://doi.org/10.12693/APhysPolA.120.322 . .

TY  - JOUR
AU  - Obradović, N.
AU  - Filipović, Suzana
AU  - Pavlović, Vladimir
AU  - Mitrić, M.
AU  - Marković, S.
AU  - Mitić, V.
AU  - Djordjević, N.
AU  - Ristić, M.M.
PY  - 2011
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2686
AB  - Mixtures of BaCO3-ZnO-TiO2 were mechanically activated using high-energy planetary ball mill during 20, 40 and 80 min. As the time of mechanical activation increased, the decrease in particle size was observed. The effect of milling on microstructure was investigated by scanning electron microscopy, as well. Sintering process was performed in air at 1100 and 1200 C for 2 h. Various phases are present within mixtures sintered at 1100 and 1200 degrees C, and almost pure BaZn2Ti4O11 phase was obtained after 80 min of milling and sintering at 1200 degrees C for 2 h.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Isothermal sintering of barium-zinc-titanate ceramics
EP  - 27
IS  - 1
SP  - 21
VL  - 37
DO  - 10.1016/j.ceramint.2010.07.001
ER  - 

@article{
author = "Obradović, N. and Filipović, Suzana and Pavlović, Vladimir and Mitrić, M. and Marković, S. and Mitić, V. and Djordjević, N. and Ristić, M.M.",
year = "2011",
abstract = "Mixtures of BaCO3-ZnO-TiO2 were mechanically activated using high-energy planetary ball mill during 20, 40 and 80 min. As the time of mechanical activation increased, the decrease in particle size was observed. The effect of milling on microstructure was investigated by scanning electron microscopy, as well. Sintering process was performed in air at 1100 and 1200 C for 2 h. Various phases are present within mixtures sintered at 1100 and 1200 degrees C, and almost pure BaZn2Ti4O11 phase was obtained after 80 min of milling and sintering at 1200 degrees C for 2 h.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Isothermal sintering of barium-zinc-titanate ceramics",
pages = "27-21",
number = "1",
volume = "37",
doi = "10.1016/j.ceramint.2010.07.001"
}

Obradović, N., Filipović, S., Pavlović, V., Mitrić, M., Marković, S., Mitić, V., Djordjević, N.,& Ristić, M.M.. (2011). Isothermal sintering of barium-zinc-titanate ceramics. in Ceramics International
Elsevier Sci Ltd, Oxford., 37(1), 21-27.
https://doi.org/10.1016/j.ceramint.2010.07.001

Obradović N, Filipović S, Pavlović V, Mitrić M, Marković S, Mitić V, Djordjević N, Ristić M. Isothermal sintering of barium-zinc-titanate ceramics. in Ceramics International. 2011;37(1):21-27.
doi:10.1016/j.ceramint.2010.07.001 .

Obradović, N., Filipović, Suzana, Pavlović, Vladimir, Mitrić, M., Marković, S., Mitić, V., Djordjević, N., Ristić, M.M., "Isothermal sintering of barium-zinc-titanate ceramics" in Ceramics International, 37, no. 1 (2011):21-27,
https://doi.org/10.1016/j.ceramint.2010.07.001 . .

TY  - JOUR
AU  - Obradović, N.
AU  - Filipović, Suzana
AU  - Pavlović, Vladimir
AU  - Maricić, A.
AU  - Mitrović, N.
AU  - Balac, I.
AU  - Ristić, M.M.
PY  - 2011
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2676
AB  - In this article the influence of mechanical activation on sintering process of magnesium-titanate and barium-zinc-titanate ceramics has been investigated. Both non-activated and mixtures treated in planetary ball mill for 80 minutes were sintered at 1100 degrees C and 1300 degrees C. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100 degrees C was to low to induce final sintering stage for both systems. Moreover, we concluded that barium-zinc-titanate ceramics exhibited better sinterability than magnesium-titanate ceramics.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Sintering of Mechanically Activated Magnesium-titanate and Barium-zinc-titanate Ceramics
EP  - 151
IS  - 2
SP  - 145
VL  - 43
DO  - 10.2298/SOS1102145O
ER  - 

@article{
author = "Obradović, N. and Filipović, Suzana and Pavlović, Vladimir and Maricić, A. and Mitrović, N. and Balac, I. and Ristić, M.M.",
year = "2011",
abstract = "In this article the influence of mechanical activation on sintering process of magnesium-titanate and barium-zinc-titanate ceramics has been investigated. Both non-activated and mixtures treated in planetary ball mill for 80 minutes were sintered at 1100 degrees C and 1300 degrees C. The influence of mechanical activation on phase composition and crystal structure has been analyzed by XRD, while the effect of activation and sintering process on microstructure was investigated by scanning electron microscopy. It has been established that temperature of 1100 degrees C was to low to induce final sintering stage for both systems. Moreover, we concluded that barium-zinc-titanate ceramics exhibited better sinterability than magnesium-titanate ceramics.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Sintering of Mechanically Activated Magnesium-titanate and Barium-zinc-titanate Ceramics",
pages = "151-145",
number = "2",
volume = "43",
doi = "10.2298/SOS1102145O"
}

Obradović, N., Filipović, S., Pavlović, V., Maricić, A., Mitrović, N., Balac, I.,& Ristić, M.M.. (2011). Sintering of Mechanically Activated Magnesium-titanate and Barium-zinc-titanate Ceramics. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 43(2), 145-151.
https://doi.org/10.2298/SOS1102145O

Obradović N, Filipović S, Pavlović V, Maricić A, Mitrović N, Balac I, Ristić M. Sintering of Mechanically Activated Magnesium-titanate and Barium-zinc-titanate Ceramics. in Science of Sintering. 2011;43(2):145-151.
doi:10.2298/SOS1102145O .

Obradović, N., Filipović, Suzana, Pavlović, Vladimir, Maricić, A., Mitrović, N., Balac, I., Ristić, M.M., "Sintering of Mechanically Activated Magnesium-titanate and Barium-zinc-titanate Ceramics" in Science of Sintering, 43, no. 2 (2011):145-151,
https://doi.org/10.2298/SOS1102145O . .

TY  - JOUR
AU  - Filipović, Suzana
AU  - Obradović, N.
AU  - Pavlović, Vladimir
AU  - Marković, S.
AU  - Mitrić, M.
AU  - Ristić, M.M.
PY  - 2010
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2352
AB  - Mixtures of MgO-TiO2 were mechanically activated using high-energy planetary ball mill during 5, 10, 20, 40, 80 and 120 minutes. Sintering process was preformed in air at 1100°-1400°C for 2h. The decrease in powder's particle size was noticed as the time of mechanical activation increased and confirmed by particle size analyzer. XRD analyses were performed in order to acquire the information about phase composition. Different ratio mixtures of MgTiO3 and Mg2TiO4 are present within all sintered samples. The effect of tribophysical activation on microstructure was investigated by scanning electron microscopy. The differential thermal gravimetric analysis has been performed in order to investigate thermal behaviour of the mixtures.
AB  - Smeše MgO-TiO2 su mehanički aktivirane u visoko-energetskom planetarnom mlinu tokom 5, 10, 20, 40, 80 i 120 minuta. Fazni sastav je određen rendgenskom difrakcijom. Sa porastom vremena mlevenja, primećeno je smanjenje veličine čestica praha. Takođe, ispitan je i efekat tribofizičke aktivacije na mikrostrukturu praha metodom skenirajuće elektronske mikroskopije. Radi ispitivanja termičkih svojstava praha, urađena je diferencijalna termijska analiza. Proces sinterovanja izveden je u vazduhu u temperaturnom opsegu od 1100°-1400°C tokom 2 sata. U svim sinterovanim uzorcima uočeno je prisustvo dve faze MgTiO3 i Mg2TiO4 ali njihov međusobni odnos koncentracija varira u odnosu na temperaturu sinterovanja.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system
EP  - 151
IS  - 2
SP  - 143
VL  - 42
DO  - 10.2298/SOS100518002F
ER  - 

@article{
author = "Filipović, Suzana and Obradović, N. and Pavlović, Vladimir and Marković, S. and Mitrić, M. and Ristić, M.M.",
year = "2010",
abstract = "Mixtures of MgO-TiO2 were mechanically activated using high-energy planetary ball mill during 5, 10, 20, 40, 80 and 120 minutes. Sintering process was preformed in air at 1100°-1400°C for 2h. The decrease in powder's particle size was noticed as the time of mechanical activation increased and confirmed by particle size analyzer. XRD analyses were performed in order to acquire the information about phase composition. Different ratio mixtures of MgTiO3 and Mg2TiO4 are present within all sintered samples. The effect of tribophysical activation on microstructure was investigated by scanning electron microscopy. The differential thermal gravimetric analysis has been performed in order to investigate thermal behaviour of the mixtures., Smeše MgO-TiO2 su mehanički aktivirane u visoko-energetskom planetarnom mlinu tokom 5, 10, 20, 40, 80 i 120 minuta. Fazni sastav je određen rendgenskom difrakcijom. Sa porastom vremena mlevenja, primećeno je smanjenje veličine čestica praha. Takođe, ispitan je i efekat tribofizičke aktivacije na mikrostrukturu praha metodom skenirajuće elektronske mikroskopije. Radi ispitivanja termičkih svojstava praha, urađena je diferencijalna termijska analiza. Proces sinterovanja izveden je u vazduhu u temperaturnom opsegu od 1100°-1400°C tokom 2 sata. U svim sinterovanim uzorcima uočeno je prisustvo dve faze MgTiO3 i Mg2TiO4 ali njihov međusobni odnos koncentracija varira u odnosu na temperaturu sinterovanja.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system",
pages = "151-143",
number = "2",
volume = "42",
doi = "10.2298/SOS100518002F"
}

Filipović, S., Obradović, N., Pavlović, V., Marković, S., Mitrić, M.,& Ristić, M.M.. (2010). Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 42(2), 143-151.
https://doi.org/10.2298/SOS100518002F

Filipović S, Obradović N, Pavlović V, Marković S, Mitrić M, Ristić M. Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system. in Science of Sintering. 2010;42(2):143-151.
doi:10.2298/SOS100518002F .

Filipović, Suzana, Obradović, N., Pavlović, Vladimir, Marković, S., Mitrić, M., Ristić, M.M., "Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system" in Science of Sintering, 42, no. 2 (2010):143-151,
https://doi.org/10.2298/SOS100518002F . .

TY  - JOUR
AU  - Ivetić, T.
AU  - Vuković, Z.
AU  - Nikolić, M.V.
AU  - Pavlović, Vladimir
AU  - Nikolić, J.R.
AU  - Minić, Dragica M.
AU  - Ristić, M.M.
PY  - 2008
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1805
AB  - Powder mixtures of zinc oxide and tin oxide in the molar ratio, ZnO:SnO2 = 2: 1, were mechanically activated in a planetary ball mill in the time intervals of 0-160 min. The adsorption-desorption isotherms, specific surface area, pore volume and pore size distribution spectra of mechanically activated powder mixtures were established by N-2 adsorption at 77 K. Microstructure analysis was performed using scanning electron microscopy (SEM) and digital pattern recognition (DPR) microstructure quantity analysis. The phase composition of the mixed powders was determined by Xray analysis. Mechanochemical activation of the ZnO-SnO2 system resulted in fine grinding of the starting particles and generation of contacts between them, mass transfer at contacts zones and formation of Zn2SnO4 spinel, which was observed after 40 min of activation.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Morphology investigation of mechanically activated ZnO-SnO2 system
EP  - 643
IS  - 3
SP  - 639
VL  - 34
DO  - 10.1016/j.ceramint.2007.01.003
ER  - 

@article{
author = "Ivetić, T. and Vuković, Z. and Nikolić, M.V. and Pavlović, Vladimir and Nikolić, J.R. and Minić, Dragica M. and Ristić, M.M.",
year = "2008",
abstract = "Powder mixtures of zinc oxide and tin oxide in the molar ratio, ZnO:SnO2 = 2: 1, were mechanically activated in a planetary ball mill in the time intervals of 0-160 min. The adsorption-desorption isotherms, specific surface area, pore volume and pore size distribution spectra of mechanically activated powder mixtures were established by N-2 adsorption at 77 K. Microstructure analysis was performed using scanning electron microscopy (SEM) and digital pattern recognition (DPR) microstructure quantity analysis. The phase composition of the mixed powders was determined by Xray analysis. Mechanochemical activation of the ZnO-SnO2 system resulted in fine grinding of the starting particles and generation of contacts between them, mass transfer at contacts zones and formation of Zn2SnO4 spinel, which was observed after 40 min of activation.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Morphology investigation of mechanically activated ZnO-SnO2 system",
pages = "643-639",
number = "3",
volume = "34",
doi = "10.1016/j.ceramint.2007.01.003"
}

Ivetić, T., Vuković, Z., Nikolić, M.V., Pavlović, V., Nikolić, J.R., Minić, D. M.,& Ristić, M.M.. (2008). Morphology investigation of mechanically activated ZnO-SnO2 system. in Ceramics International
Elsevier Sci Ltd, Oxford., 34(3), 639-643.
https://doi.org/10.1016/j.ceramint.2007.01.003

Ivetić T, Vuković Z, Nikolić M, Pavlović V, Nikolić J, Minić DM, Ristić M. Morphology investigation of mechanically activated ZnO-SnO2 system. in Ceramics International. 2008;34(3):639-643.
doi:10.1016/j.ceramint.2007.01.003 .

Ivetić, T., Vuković, Z., Nikolić, M.V., Pavlović, Vladimir, Nikolić, J.R., Minić, Dragica M., Ristić, M.M., "Morphology investigation of mechanically activated ZnO-SnO2 system" in Ceramics International, 34, no. 3 (2008):639-643,
https://doi.org/10.1016/j.ceramint.2007.01.003 . .

TY  - JOUR
AU  - Pavlović, Vera P.
AU  - Stojanović, B.D.
AU  - Pavlović, Vladimir
AU  - Marinković-Stanojević, Z.
AU  - Živković, Lj.
AU  - Ristić, M.M.
PY  - 2008
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1804
AB  - In this article the solid state reaction of BaTiO3 formation from a mechanically activated BaCO3-TiO2 system has been investigated. An equimolar mixture of BaCO3 and TiO2 powders was activated in a planetary ball mill in a continual regime for 0, 30 and 90 min, pressed and thermally treated up to 1200°C. The effect of the milling and firing regime on the phase formation was investigated by the X-ray diffraction (XRD) method and differential thermal analysis (DTA). Deconvolution of the experimental DTA curve corresponding to the BaTiO3 synthesis process has been performed. The influence of the activation time on the change of characteristic temperature for each elementary step in the complete solid-state reaction of BaTiO3 formation, was analyzed. These results were correlated with the ones obtained by SEM characterization and by XRD analysis.
AB  - U ovome radu je analiziran uticaj mehaničke aktivacije sistema BaCO3- TiO2 na formiranje BaTiO3. Ekvimolarne smeše praha BaCO3 i TiO2 su aktivirane u planetarnom mlinu u kontinualnom režimu tokom 0, 30 i 90 min. Uzorci su zatim presovani i termički tretirani do 1200oC. Efekat mlevenja i zagrevanja na promene faza je analiziran primenom rendgenske fazne analize i diferencijalne termijske analize. Izvršena je dekonvolucija eksperimentalno dobijene DTA krive koja odgovara procesu sinteze BaTiO3, kao i analiza uticaja vremena aktivacije na promene karakteristične temperature za svaki pojedinačni elementarni proces tokom sinteze barijum titanata. Ovi rezultati su korelisani sa rezultatima dobijenim SEM i XRD analizom.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Synthesis of BaTiO3 from a mechanically activated BaCO3-TiO2 system
EP  - 26
IS  - 1
SP  - 21
VL  - 40
DO  - 10.2298/SOS0801021P
ER  - 

@article{
author = "Pavlović, Vera P. and Stojanović, B.D. and Pavlović, Vladimir and Marinković-Stanojević, Z. and Živković, Lj. and Ristić, M.M.",
year = "2008",
abstract = "In this article the solid state reaction of BaTiO3 formation from a mechanically activated BaCO3-TiO2 system has been investigated. An equimolar mixture of BaCO3 and TiO2 powders was activated in a planetary ball mill in a continual regime for 0, 30 and 90 min, pressed and thermally treated up to 1200°C. The effect of the milling and firing regime on the phase formation was investigated by the X-ray diffraction (XRD) method and differential thermal analysis (DTA). Deconvolution of the experimental DTA curve corresponding to the BaTiO3 synthesis process has been performed. The influence of the activation time on the change of characteristic temperature for each elementary step in the complete solid-state reaction of BaTiO3 formation, was analyzed. These results were correlated with the ones obtained by SEM characterization and by XRD analysis., U ovome radu je analiziran uticaj mehaničke aktivacije sistema BaCO3- TiO2 na formiranje BaTiO3. Ekvimolarne smeše praha BaCO3 i TiO2 su aktivirane u planetarnom mlinu u kontinualnom režimu tokom 0, 30 i 90 min. Uzorci su zatim presovani i termički tretirani do 1200oC. Efekat mlevenja i zagrevanja na promene faza je analiziran primenom rendgenske fazne analize i diferencijalne termijske analize. Izvršena je dekonvolucija eksperimentalno dobijene DTA krive koja odgovara procesu sinteze BaTiO3, kao i analiza uticaja vremena aktivacije na promene karakteristične temperature za svaki pojedinačni elementarni proces tokom sinteze barijum titanata. Ovi rezultati su korelisani sa rezultatima dobijenim SEM i XRD analizom.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Synthesis of BaTiO3 from a mechanically activated BaCO3-TiO2 system",
pages = "26-21",
number = "1",
volume = "40",
doi = "10.2298/SOS0801021P"
}

Pavlović, V. P., Stojanović, B.D., Pavlović, V., Marinković-Stanojević, Z., Živković, Lj.,& Ristić, M.M.. (2008). Synthesis of BaTiO3 from a mechanically activated BaCO3-TiO2 system. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 40(1), 21-26.
https://doi.org/10.2298/SOS0801021P

Pavlović VP, Stojanović B, Pavlović V, Marinković-Stanojević Z, Živković L, Ristić M. Synthesis of BaTiO3 from a mechanically activated BaCO3-TiO2 system. in Science of Sintering. 2008;40(1):21-26.
doi:10.2298/SOS0801021P .

Pavlović, Vera P., Stojanović, B.D., Pavlović, Vladimir, Marinković-Stanojević, Z., Živković, Lj., Ristić, M.M., "Synthesis of BaTiO3 from a mechanically activated BaCO3-TiO2 system" in Science of Sintering, 40, no. 1 (2008):21-26,
https://doi.org/10.2298/SOS0801021P . .

TY  - CONF
AU  - Pavlović, Vera P.
AU  - Nikolić, M.V.
AU  - Nikolić, Z.
AU  - Branković, G.
AU  - Zivković, Lj.
AU  - Pavlović, Vladimir
AU  - Ristić, M.M.
PY  - 2007
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1524
AB  - Ceramic materials with a perovskite related structures such as non-doped and doped barium titanate ceramics are attracting much interest for their application as capacitor dielectrics, resistors, thermal sensors, etc. Since mechanical activation can be used in order to modify properties of these materials, in this study microstructure evolution and electric properties of mechanically activated BaTiO3 have been analyzed. The sintering process of high purity non-doped mechanically activated BaTiO3 was monitored using a sensitive dilatometer with a heating rate of 10 degrees C/min. Investigation of the microstructure evolution of mechanically activated BaTiO3 was performed using scanning electron microscope (SEM) and digital pattern recognition (DPR) methods. A dielectric study of the paraelectric-ferroelectric phase transition in the barium titanate ceramics was performed by recording the temperature dependence of dielectric permittivity.
PB  - Elsevier Sci Ltd, Oxford
C3  - Journal of the European Ceramic Society
T1  - Microstructural evolution and electric properties of mechanically activated BaTiO3 ceramics
EP  - 579
IS  - 2-3
SP  - 575
VL  - 27
DO  - 10.1016/j.jeurceramsoc.2006.04.074
ER  - 

@conference{
author = "Pavlović, Vera P. and Nikolić, M.V. and Nikolić, Z. and Branković, G. and Zivković, Lj. and Pavlović, Vladimir and Ristić, M.M.",
year = "2007",
abstract = "Ceramic materials with a perovskite related structures such as non-doped and doped barium titanate ceramics are attracting much interest for their application as capacitor dielectrics, resistors, thermal sensors, etc. Since mechanical activation can be used in order to modify properties of these materials, in this study microstructure evolution and electric properties of mechanically activated BaTiO3 have been analyzed. The sintering process of high purity non-doped mechanically activated BaTiO3 was monitored using a sensitive dilatometer with a heating rate of 10 degrees C/min. Investigation of the microstructure evolution of mechanically activated BaTiO3 was performed using scanning electron microscope (SEM) and digital pattern recognition (DPR) methods. A dielectric study of the paraelectric-ferroelectric phase transition in the barium titanate ceramics was performed by recording the temperature dependence of dielectric permittivity.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Journal of the European Ceramic Society",
title = "Microstructural evolution and electric properties of mechanically activated BaTiO3 ceramics",
pages = "579-575",
number = "2-3",
volume = "27",
doi = "10.1016/j.jeurceramsoc.2006.04.074"
}

Pavlović, V. P., Nikolić, M.V., Nikolić, Z., Branković, G., Zivković, Lj., Pavlović, V.,& Ristić, M.M.. (2007). Microstructural evolution and electric properties of mechanically activated BaTiO3 ceramics. in Journal of the European Ceramic Society
Elsevier Sci Ltd, Oxford., 27(2-3), 575-579.
https://doi.org/10.1016/j.jeurceramsoc.2006.04.074

Pavlović VP, Nikolić M, Nikolić Z, Branković G, Zivković L, Pavlović V, Ristić M. Microstructural evolution and electric properties of mechanically activated BaTiO3 ceramics. in Journal of the European Ceramic Society. 2007;27(2-3):575-579.
doi:10.1016/j.jeurceramsoc.2006.04.074 .

Pavlović, Vera P., Nikolić, M.V., Nikolić, Z., Branković, G., Zivković, Lj., Pavlović, Vladimir, Ristić, M.M., "Microstructural evolution and electric properties of mechanically activated BaTiO3 ceramics" in Journal of the European Ceramic Society, 27, no. 2-3 (2007):575-579,
https://doi.org/10.1016/j.jeurceramsoc.2006.04.074 . .

TY  - CONF
AU  - Pavlović, Vera P.
AU  - Nikolić, M.V.
AU  - Spasojević, V.
AU  - Blanusa, J.
AU  - Zivković, Lj.
AU  - Stojanović, B.D.
AU  - Pavlović, Vladimir
AU  - Ristić, M.M.
PY  - 2006
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1340
AB  - In this paper the influence of tribophysical activation on non-isothermal sintering of barium titanate has been investigated. BaTiO3 Powders were tribophysically activated in a planetary ball mill for 0, 60 and 120 min., pressed and non-isothermally sintered up to 1380 degrees C. Dilatometric analysis was performed in air in the temperature range from room temperature to 1380 degrees C with heating rates of 10, 20 and 30 degrees C/min. The samples were analyzed by the X-ray powder diffraction method. Investigation of the morphology of microstructure constituents was performed using the scanning electron microsocopy method. With the purpose of optimizing technological parameters the results obtained by microstructure analysis were correlated with the results of quantitative dilatometric analysis.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
C3  - Materials Science Forum
T1  - The influence of tribophysical activation on non-isothermal sintering of BaTiO3 ceramics
EP  - 1570
SP  - 1566
VL  - 514-516
DO  - 10.4028/www.scientific.net/MSF.514-516.1566
ER  - 

@conference{
author = "Pavlović, Vera P. and Nikolić, M.V. and Spasojević, V. and Blanusa, J. and Zivković, Lj. and Stojanović, B.D. and Pavlović, Vladimir and Ristić, M.M.",
year = "2006",
abstract = "In this paper the influence of tribophysical activation on non-isothermal sintering of barium titanate has been investigated. BaTiO3 Powders were tribophysically activated in a planetary ball mill for 0, 60 and 120 min., pressed and non-isothermally sintered up to 1380 degrees C. Dilatometric analysis was performed in air in the temperature range from room temperature to 1380 degrees C with heating rates of 10, 20 and 30 degrees C/min. The samples were analyzed by the X-ray powder diffraction method. Investigation of the morphology of microstructure constituents was performed using the scanning electron microsocopy method. With the purpose of optimizing technological parameters the results obtained by microstructure analysis were correlated with the results of quantitative dilatometric analysis.",
publisher = "Trans Tech Publications Ltd, Durnten-Zurich",
journal = "Materials Science Forum",
title = "The influence of tribophysical activation on non-isothermal sintering of BaTiO3 ceramics",
pages = "1570-1566",
volume = "514-516",
doi = "10.4028/www.scientific.net/MSF.514-516.1566"
}

Pavlović, V. P., Nikolić, M.V., Spasojević, V., Blanusa, J., Zivković, Lj., Stojanović, B.D., Pavlović, V.,& Ristić, M.M.. (2006). The influence of tribophysical activation on non-isothermal sintering of BaTiO3 ceramics. in Materials Science Forum
Trans Tech Publications Ltd, Durnten-Zurich., 514-516, 1566-1570.
https://doi.org/10.4028/www.scientific.net/MSF.514-516.1566

Pavlović VP, Nikolić M, Spasojević V, Blanusa J, Zivković L, Stojanović B, Pavlović V, Ristić M. The influence of tribophysical activation on non-isothermal sintering of BaTiO3 ceramics. in Materials Science Forum. 2006;514-516:1566-1570.
doi:10.4028/www.scientific.net/MSF.514-516.1566 .

Pavlović, Vera P., Nikolić, M.V., Spasojević, V., Blanusa, J., Zivković, Lj., Stojanović, B.D., Pavlović, Vladimir, Ristić, M.M., "The influence of tribophysical activation on non-isothermal sintering of BaTiO3 ceramics" in Materials Science Forum, 514-516 (2006):1566-1570,
https://doi.org/10.4028/www.scientific.net/MSF.514-516.1566 . .

TY  - JOUR
AU  - Nikolić, M.V.
AU  - Pavlović, Vera P.
AU  - Pavlović, Vladimir
AU  - Ristić, M.M.
PY  - 2006
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1337
AB  - Barium-titanate powder was mechanically activated in a planetary-ball mill for 60 and 120 minutes. Non-isothermal sintering of non-activated and activated powder samples was investigated using a dilatometer in the temperature interval from room to 1380oC with three different heating rates (10, 20 and 30oC/min). Early-stage sintering mechanisms for all three types of samples were analyzed, showing significant differences between the non-activated and mechanically activated samples.
AB  - Prah barijum-titanata je mehanički aktiviran u planetarnom mlinu sa kuglicama 60 i 120 minuta. Neizotermsko sinterovanje neaktiviranog i aktiviranih uzoraka proučeno je u dilatometru u temperaturskom intervalu od sobne do 1380oS sa tri različite brzine zagrevanja (10, 20 i 30oS/min). Mehanizmi ranih stadijuma sinterovanja su analizirani za sva tri tipa uzoraka i uočene su značajne razlike između neaktiviranih i mehanički aktiviranih uzoraka.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3
EP  - 244
IS  - 3
SP  - 239
VL  - 38
DO  - 10.2298/SOS0603239N
ER  - 

@article{
author = "Nikolić, M.V. and Pavlović, Vera P. and Pavlović, Vladimir and Ristić, M.M.",
year = "2006",
abstract = "Barium-titanate powder was mechanically activated in a planetary-ball mill for 60 and 120 minutes. Non-isothermal sintering of non-activated and activated powder samples was investigated using a dilatometer in the temperature interval from room to 1380oC with three different heating rates (10, 20 and 30oC/min). Early-stage sintering mechanisms for all three types of samples were analyzed, showing significant differences between the non-activated and mechanically activated samples., Prah barijum-titanata je mehanički aktiviran u planetarnom mlinu sa kuglicama 60 i 120 minuta. Neizotermsko sinterovanje neaktiviranog i aktiviranih uzoraka proučeno je u dilatometru u temperaturskom intervalu od sobne do 1380oS sa tri različite brzine zagrevanja (10, 20 i 30oS/min). Mehanizmi ranih stadijuma sinterovanja su analizirani za sva tri tipa uzoraka i uočene su značajne razlike između neaktiviranih i mehanički aktiviranih uzoraka.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3",
pages = "244-239",
number = "3",
volume = "38",
doi = "10.2298/SOS0603239N"
}

Nikolić, M.V., Pavlović, V. P., Pavlović, V.,& Ristić, M.M.. (2006). Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 38(3), 239-244.
https://doi.org/10.2298/SOS0603239N

Nikolić M, Pavlović VP, Pavlović V, Ristić M. Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3. in Science of Sintering. 2006;38(3):239-244.
doi:10.2298/SOS0603239N .

Nikolić, M.V., Pavlović, Vera P., Pavlović, Vladimir, Ristić, M.M., "Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3" in Science of Sintering, 38, no. 3 (2006):239-244,
https://doi.org/10.2298/SOS0603239N . .

TY  - CONF
AU  - Pavlović, Vladimir
AU  - Marinković, Z.V.
AU  - Pavlović, Vera P.
AU  - Nikolić, Z.
AU  - Stojanović, B.
AU  - Ristić, M.M.
PY  - 2002
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/367
AB  - Phase transformations and thermal effects of BaTiO 3 ceramics due to influence of mechanical activation were investigated. Equimolar mixture of BaCO 3 and TiO 2 powders was activated in high energy vibromill for various grinding times. Specific surface area determinations of initial and activated powders were carried out. The phase composition and crystallographic data of initial and thermal treated powders was determined using X-ray powder diffraction method. Heating process was investigated using differential thermal analysis.
C3  - Ferroelectrics
T1  - Phase transformations and thermal effects of mechanically activated BaCO3 -TiO2 system
EP  - 396
SP  - 391
VL  - 271
DO  - 10.1080/713716214
ER  - 

@conference{
author = "Pavlović, Vladimir and Marinković, Z.V. and Pavlović, Vera P. and Nikolić, Z. and Stojanović, B. and Ristić, M.M.",
year = "2002",
abstract = "Phase transformations and thermal effects of BaTiO 3 ceramics due to influence of mechanical activation were investigated. Equimolar mixture of BaCO 3 and TiO 2 powders was activated in high energy vibromill for various grinding times. Specific surface area determinations of initial and activated powders were carried out. The phase composition and crystallographic data of initial and thermal treated powders was determined using X-ray powder diffraction method. Heating process was investigated using differential thermal analysis.",
journal = "Ferroelectrics",
title = "Phase transformations and thermal effects of mechanically activated BaCO3 -TiO2 system",
pages = "396-391",
volume = "271",
doi = "10.1080/713716214"
}

Pavlović, V., Marinković, Z.V., Pavlović, V. P., Nikolić, Z., Stojanović, B.,& Ristić, M.M.. (2002). Phase transformations and thermal effects of mechanically activated BaCO3 -TiO2 system. in Ferroelectrics, 271, 391-396.
https://doi.org/10.1080/713716214

Pavlović V, Marinković Z, Pavlović VP, Nikolić Z, Stojanović B, Ristić M. Phase transformations and thermal effects of mechanically activated BaCO3 -TiO2 system. in Ferroelectrics. 2002;271:391-396.
doi:10.1080/713716214 .

Pavlović, Vladimir, Marinković, Z.V., Pavlović, Vera P., Nikolić, Z., Stojanović, B., Ristić, M.M., "Phase transformations and thermal effects of mechanically activated BaCO3 -TiO2 system" in Ferroelectrics, 271 (2002):391-396,
https://doi.org/10.1080/713716214 . .