Ultrasound modifications of physical properties of BaTiO3 powders

The starting BaTiO3 powder was prepared by solid state reaction, and then modified by ultrasound into powders with different physical characteristics. The prepared barium titanate powders were characterized by X-ray powder diffraction (XRD), laser particle size analyzer, also, specific surface area and powders density were determined. The studies indicate that physical properties of BaTiO3 powders were changed by sonochemical treatment. However, tetragonal crystal structure was maintained. It is shown that sonochemical method can be used for easy modification of barium titanate powder characteristics.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Ultrasound modifications of physical properties of BaTiO3 powders

The starting BaTiO3 powder was prepared by solid state reaction, and then modified by ultrasound into powders with different physical characteristics. The prepared barium titanate powders were characterized by X-ray powder diffraction (XRD), laser particle size analyzer, also, specific surface area and powders density were determined. The studies indicate that physical properties of BaTiO3 powders were changed by sonochemical treatment. However, tetragonal crystal structure was maintained. It is shown that sonochemical method can be used for easy modification of barium titanate powder characteristics.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Ultrasound Modifications od Physical Properties of BaTiO3 Powders

Poster presented at the VIII Conference on Fundamental and. Applied Aspects of Physical Chemistry 2006, Belgrade, Serbia, September 26-29, 200

The Low Temperature Aerosol Synthesis of YAG:Ce3+ Nanostructures: comparative Study of XRPD Microstructural Parameters

Poster presented at the 8th Conference of Yugoslav Materials Research Society – YUCOMAT 2006, Herceg Novi, Montenegro, September 4-8, 200

Radiološka karakterizacija alkalno aktivnih materijala koji sadrže drveni i leteći pepeo

Improperly storage of fly ash as industrial wastes has been a cause of land contamination issues. These wastes or by-products have the potential to be used as secondary raw materials in construction, promoting the concept of a circular economy that will avoid land contamination. Here we evaluate radiological environmental impacts when wastes that contain elevated levels of naturally occurring radionuclides (NORs) such as fly ash and wood ash are made into 'green cements' such as geopolymers or alkali-activated materials (AAMs). Alkali-activated materials were formed by alkali-activation reaction of wood and fly ash, as a solid precours, and alkali activator solution, sodium hydroxide and sodium silicate. Three differente concentration of alkali solution were used. Determination of radionuclide content was performed by means of gamma-ray spectrometry. The external absorbed gamma dose rate was 68.6-98.1 nGy/h, and external radiation hazard index for alkali-activated material AAM4, AAM6 and AAM12 were 0.544 Bq/kg, 0.575 Bq/kg and 0.403 Bq/kg, respectively. The results of activity concentration measurements in alkali-activated materials indicate potential of their safe application in building constructions. In terms of some the structural characterizations the obtained alkali activated materials were examined.Nepravilno skladištenje letećeg pepela kao industrijskog otpada je uzrok problema kontaminacije zemljišta. Ovaj otpad ili nusproizvodi imaju potencijal da se koriste kao sekundarne sirovine u građevinarstvu, promovišući koncept kružne ekonomije kako bi se izbegla kontaminaciju zemljišta. U ovom radu procenjuje se radiološki uticaj na životnu sredinu kada se otpad koji sadrži povišene nivoe prirodnih radionuklida kao što su leteći pepeo i drveni pepeo pretvara u zelene cemente kao što su geopolimeri ili alkalno aktivirani materijali (AAM). Alkalno-aktivirani materijali nastali su reakcijom alkalne aktivacije drvenog i elektrofilterskog pepela, kao čvrstih prekursora, i rastvora alkalnog aktivatora, natrijum hidroksida i natrijum silikata. Korišćene su tri različite koncentracije ratvora alkalnog aktivatora. Određivanje sadržaja radionuklida urađeno je spektrometrijom gama zraka. Jačina apsorbovane doze bila je 68,6-98,1 nGy/h, a Hex (Bq/kg ) za alkalno aktivirane materijale AAM4, AAM6 i AAM12 je bio 0,544 Bq/kg, 0,575 Bq/kg i 0,403 Bq/kg, respektivno. Rezultati merenja koncentracije aktivnosti u alkalno aktiviranim materijalima ukazuju na potencijal njihove bezbedne primene u građevinskim konstrukcijama. Alkalno aktivirani materijali su ispitani i u pogledu nekih strukturnih karakteristika.XXXII Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, 4-6. oktobar 2023; Budva, Crna GoraProceedings: [https://vinar.vin.bg.ac.rs/handle/123456789/11602

Radiological and Structural Characterization of Raw and Alkali-Activated Wood Ash and Metakaolin Blends

The aim of the presented research was to investigate the application possibility of wood ash and metakaolin to obtain alkali-activated materials as relatively new materials in the building industry. Thus, in order to assess the adequate use of these waste materials, structural and radiological characteristics should be considered. Until now, the focus has been on ash from thermal power plants produced by burning coal, but a large part of households in our country have individual fireplaces in which wood is used as the basic raw material; thus, it is very interesting to measure the activity concentration of radionuclide in wood ash as well as the possibility of reusing that ash for other purposes. All materials were studied, in terms of physical and chemical characteristics, by methods such as X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, and scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS). XRD measurements of wood ash samples showed that it consists of calcite and larnite. FTIR spectroscopy revealed a polymeric Si–O–Al framework in alkali-activated materials and Si–O bonding bands corresponding to silicon dioxide. Determination of radionuclide content was performed by means of gamma-ray spectrometry. Results showed that the alkaline activation process led to the decrease in the activity concentration of radionuclides detected in the measured samples. External radiation hazard index (Hex) for wood ash was reduced by more than 50% after alkali activation. The results of activity concentration measurements in alkali-activated materials indicate potential for their safe application in building construction

XRD analysis of calcium phosphate and biocomposite calcium phosphate/bioresorbable polymer

Composite biomaterials based on calcium phosphate ceramic due to their high bioactivity are of interest for biological application and bone tissue repair. Structural and microstructural parameters of inorganic constituent of these materials are very important for the synthesis and characterization of composites. Quantitative and qualitative content, crystallite size of phases, as well as the degree of crystallinity have a great influence on the quality of composites, their application and bone tissue repair. X-ray diffractometry was employed to investigate the components of biocomposite materials, calcium phosphate (CaP) ceramic and poly-DL-lactide-coglycolide (DLPLG) polymer, as well as the biocomposite obtained from the mentioned components. Composite biomaterial was obtained by modified emulsion process. Using the Rietveld refinement, we analyzed CaP as an inorganic component of the composite, whence we have determined structural and microstructural properties of ceramic component of the investigated composite. The results obtained by structure refinement show that calcium phosphate ceramic materials synthesized at room temperature contain hydroxyapatite HAp as a predominant phase. The calculated Ca/P ratio is 1.667. The Rietveld analysis revealed lattice parameters a(angstrom)=9.4324(7) and c(angstrom)=6.8785(6) that are in agreement with the theoretical values.Recent Developments in Advanced Materials and Processes, 7th Conference of the Yugoslav-Materials-Research-Society (Yu-MRS), Sep 12-16, 2005, Herceg Novi, Montenegr

Preparation of 99mTc PLGA and its Distribution Studies

Poster presented at the 10th Conference of the Materials Research Society of Serbia - YUCOMAT 2008, Herceg Novi, Montenegro, September 8-12, 2008

Synthesis of ZnO and ZrO2 Powders by Mechanochemical Processing

The ZnO and ZrO2 powders were prepared by mechanochemical processing and subsequent heat treatment of the starting powder of precursors mixture of ZnCl2 and Ca(OH)2, and ZrOCl2·8H2O and NaOH, respectively. Inert salt matrix, ether CaCl2 or NaCl, which prevents particle agglomeration was formed during mechanochemical solid state reaction. After mechanochemical treatment, samples were calcined at various temperatures. Selective removal of the matrix phase by washing the resulting powder with appropriate solvent yields almost pure ZnO and ZrO2 powders. Characterization of the powders was performed by X-ray diffraction (XRD), differential thermal and thermo gravimetric analysis (DTA−TG) and scanning electron microscopy (SEM).Materials Science Forum 55