Contribution of Frenkel's theory to the development of materials science

The original and comprehensive research of Yakov Rich Frenkel in physics and physical chemistry of condensed states, nuclear physics, electrodynamics, science of sintering has significantly contributed to the development of modern scientific knowledge and his scientific ideas are still an inspiration to many scientists. Having in mind the wealth of scientific ideas he had in the research of electroconductivity in metals, crystal structure imperfections and phase transitions and in founding the science of sintering, the contribution of individual theories of Frenkel of significance to materials science are presented in this paper

TiO2 based nanomaterials and nanostructures for green convergent technologies and environmental protection

Imajući u vidu značaj razvoja naprednih nanomaterijala za zaštitu prirodne okoline, u ovome radu su prezentovane primene nanomaterijala i nanostruktura na bazi TiO2 u oblastima obnovljivih izvora energije, hemijske i bio dekontaminacije. Objašnjena je uloga TiO2 u formiranju kompozitnih hibridnih struktura za prikupljanje solarne energije, kao i primena različitih antimikrobnih materijala na bazi TiO2 koji se koriste za fotokatalitičko uklanjanje polutanata. Naročita pažnja je posvećena strukturi i svojstvima titan dioksidnih nanotuba dobijenih primenom metode elektrohemijske anodizacije i njihova primena u bio dekontaminaciji.Taking into account the importance of development of the advanced nanomaterials for the environmental protection, in this article the application of TiO2 based nanomaterials and nanostructures in the fields of renewable energy, chemical and bio decontamination has been presented. The role of TiO2 in formation of composite hybrid structures for solar energy harvesting has been explained, as well as the use photocatalytic degradation of pollutants. properties of TiO2 nanotubes obtained by decontamination

Automatska mikrostrukturna analiza sinterovanih materijala

In this article the new approach to automatic microstructure analysis of the sintered materials has been presented. The method is based on contour recognition and decomposition of digital image, according to their gray scale intensity and the use of log-hyperbolic grain size distribution and it has been successfully applied on microstructure analysis of BaTiO3 sintered under non isothermal conditions.U ovom radu je prezentovana nova metoda za automatsku mikrostrukturnu analizu materijala. Metoda je bazirana na prepoznavanju kontura i dekompoziciji digitalne slike na osnovu fotometrijskih zakona, kao i na primeni log hiperbolične distribucije. Ova metoda je uspešno primenjena za mikrostrukturnu analizu neizotermski sinterovanog barijum-titanata

Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3

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

Analysis of the initial-stage sintering of mechanically activated SrTiO3

The initial-stage of sintering plays a significant role in determining the final microstructure that defines the main characteristics of electroceramics materials such as functional properties. In this article non-isothermal sintering of non-activated and mechanically activated SrTiO3 samples was investigated up to 1300 °C. Dilatometric curves indicate that mechanical activation leads to an earlier onset of sintering, suggesting that it should lead to a more homogenous and denser sintered product. Analysis of the initial stage of sintering reveals that the sintering process of all examinated samples consists of two or three overlapping single-step processes, with a change in the dominant mass transport mechanism. The values of apparent activation energy of the considered single-step process exhibit a significant decrease with an increase in mechanical activation time. The values of the density of samples after isothermal sintering indicate that the final stage of sintering has not been reached by 1300 °C

TiO2 based nanomaterials and nanostructures for green convergent technologies and environmental protection

Imajući u vidu značaj razvoja naprednih nanomaterijala za zaštitu prirodne okoline, u ovome radu su prezentovane primene nanomaterijala i nanostruktura na bazi TiO2 u oblastima obnovljivih izvora energije, hemijske i bio dekontaminacije. Objašnjena je uloga TiO2 u formiranju kompozitnih hibridnih struktura za prikupljanje solarne energije, kao i primena različitih antimikrobnih materijala na bazi TiO2 koji se koriste za fotokatalitičko uklanjanje polutanata. Naročita pažnja je posvećena strukturi i svojstvima titan dioksidnih nanotuba dobijenih primenom metode elektrohemijske anodizacije i njihova primena u bio dekontaminaciji.Taking into account the importance of development of the advanced nanomaterials for the environmental protection, in this article the application of TiO2 based nanomaterials and nanostructures in the fields of renewable energy, chemical and bio decontamination has been presented. The role of TiO2 in formation of composite hybrid structures for solar energy harvesting has been explained, as well as the use photocatalytic degradation of pollutants. properties of TiO2 nanotubes obtained by decontamination

Automatic microstructure analysis of sintered materials

U ovom radu je prezentovana nova metoda za automatsku mikrostrukturnu analizu materijala. Metoda je bazirana na prepoznavanju kontura i dekompoziciji digitalne slike na osnovu fotometrijskih zakona, kao i na primeni log hiperbolične distribucije. Ova metoda je uspešno primenjena za mikrostrukturnu analizu neizotermski sinterovanog barijum-titanata.In this article the new approach to automatic microstructure analysis of the sintered materials has been presented. The method is based on contour recognition and decomposition of digital image, according to their gray scale intensity and the use of log-hyperbolic grain size distribution and it has been successfully applied on microstructure analysis of BaTiO3 sintered under non isothermal conditions