Influence of magnetic field on the reduction of 4,8-diaza-3,6,6,9-tetramethyl undecane-3,8-diene2,10-dione dioxime

The influence of the magnetic field with the magnetic induction up to 1,35T on the reduction of 4,8-diaza-3,6,6,9-tetramethylundecane-3,8-diene-2,10-dione dioxime (DI) in anhydrous protic solvents (anhydrous ethanol and 2-propanol) was defined. As the reductants NaBH4 and KBH4 were usedPhysical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Synthesis Procedure for the Preparation of CaCu3Ti4O12

Poster presented at the 12th Annual Conference of the Materials Research Society of Serbia - YUCOMAT 2010, Herceg Novi, Montenegro, 6–10. septembar 2010

Synthesis and dielectric properties of calcium copper titanate (CCTO) based ceramics

The perovskite CaCu3Ti4O12 (CCTO) powders with various oxide phase impurities were synthesized via citric gel combustion method. Influence of citric acid amount used for gel preparation was examined in order to lower CCTO formation temperature to obtain powders with less impurities and better micro structural characteristics. Prepared powders were pressed into pellets and sintered at 1000 °C. Effects of oxide component impurities, such as CuO, rutile, anatase, CaTiO3 were examined on sintering behavior and dielectric properties of ceramics. Phase composition of powders and sintered specimens were determined by XRD, microstructure powders and sintered bodies were observed by SEM, and dielectric constants of sintered ceramics were measured by Wayne-Kerr B224 universal bridge

The effect of simulated acid rain on metal desorption from cetraria islandica

In this paper the possibility of extracting metals: K, Al, Ca, Mg, Fe, Cu, Ba, Zn, Mn and Sr, from Cetraria islandica lichen with solutions simulating acid rain (H2SO4- HNO3-(NH4)2SO4), pH 2.00 (1) and 3.28 (2) has been investigated. The results obtained suggest that the investigated elements can be classified into ones where the highest percentage was extracted with the first extraction (K, Al, Mg, Ba, Zn and Mn) and others where the extraction percentage is relatively uniform (Ca and Fe). This indicated different bonding methods in lichen that is in accordance with literature data where two cation bonding methods in lichen were shown.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Termodinamičke konstante stabilnosti kompleksa Fe(III)-jona sa orciprenalinom i fenilefrinom

The concentration stability constants of Fe(III)-orciprenaline complex and Fe(III)-phenylephrine complex were calculated for three different ionic strengths, by modificated Bjerrum's method. The values of thermodynamic stability constants are determined from curve log β = f (I1/2), as interception at ordinate. From the determined thermodynamic stability constants logβ10 =8,28 and logβ02 = 16,24 of the complexes investigated, the values of the ∆G10= - 46,87 kJ/mol and, AG° = -92,76 kJ/mol were calculated for Fe(III)-orciprenaline and Fe(III)- phenylephrine complexes respectively.Za komplekse Fe(III)-fenilefrin i Fe(III)-orciprenalin određene su vrednosti koncentracionih konstanti stabilnosti na tri jonske jačine (0,024; 0,050 0,075 mol/dm3). Na osnovu ovih vrednosti izračunate su termodinamičke konstante stabilnosti ovih kompleksa ekstrapolacijom dijagrama logβn=f(I) na vrednost I=0. Dobijena vrednost za kompleks Fe(III)-fenilefrin je logβ0 2 = 16,24, a za kompleks Fe(III)-orciprenalin ona iznosi logβ10= 8,28. Izračunate su promene standardne Gibbsove energije za reakciju stvaranja kompleksa: ∆G1°= -46,87 kJ/mol za Fe(III)- orciprenalin i ∆G°2 = -92,76 kJ/mol za Fe(III)-fenilefrin

Hydrothermal synthesis of ZnO nanostructures with different morphologies and their antimicrobial activity against Escherihia coli and Staphylococus aureus bacterial cultures

Considering that many very important properties that determine the use of material for a range of purposes depend on size and morphology of the particles of which the material is made up of exceptional importance is the synthesis of particles of controlled morphology and dimensions. Nanoparticle metal oxides represent a new class of important materials that are increasingly being developed for use in research and health-related applications. Zinc oxide is currently being investigated as an antimicrobial agent in both microscale and nanoscale formulations. Results have indicated that ZnO nanoparticles show antibacterial activity apparently greater than for microparticles. In this study, we generally attempt to examine influence of size and particularly shape of ZnO nanoparticles synthesized through a controlled hydrothermal method, on the antibacterial activity toward Escherichia coli (Gram-negative bacteria) and Staphylococcus aureus (Gram-positive bacteria). Characterization of the prepared ZnO nanopowders was performed using experimental technique such as XRD analysis, FE SEM, HR TEM, UV VIS and Malvern’s Master Sizer instrument for particle size distribution. The antibacterial properties of synthesized ZnO nanostructures were done using a colony count method. Apart from different forms of prepared ZnO nanoparticles, antimicrobial tests showed impressive antibacterial properties, above 99% microbial cells reduction, toward gram positive bacteria S. Aureus and gram negative bacteria E. Colli

Lichen - bioindicators of radioactive pollution of the environment

Tkivo lišajeva odražava elementarni sastav životne sredine, pa su oni dobri bioindikatori i biomonitori zagađenja životne sredine, jer nemaju formiran koren, list, stablo, kutikulu i stome, a vodu i mineralne materije upijaju celom površinom talusa. Nivoi aktivnosti 137Cs u lišajevima BiH 1985. godine bili su od 397 do 696 Bq/kg. Srednji nivo aktivnosti 137Cs u lišajevima vrste Evernia prunastri u prvoj polovini 1987. godine je bio 10161 Bq/kg, odnosno, 13610 Bq/kg u drugoj polovini iste godine, a u lišajevima vrste Cetraria islandica je u drugoj polovini 1987. godine bio 10392 Bq/kg. U periodu 1986-2015. godina, nivoi aktivnosti 137Cs u ispitivanim uzorcima lišajeva opadaju. Srednji nivo aktivnosti 137Cs u lišajevima vrste Hypogimnia physodes sakupljenim 2010. godine u NP Đerdap bio je 150 Bq/kg, a 2015. godine 128 Bq/kg. Nivoi aktivnosti 137Cs su u nivoima pre akcidenta u Černobilju (1986. god), tj. novih zagađenja ovim izotopom nije bilo.Lichen tissue reflects the elementary composition of the environment. They are good bioindicators and biomonitors of environment pollution as they do not have a formed root, leaves, trunk, cuticula and stoma and they absorb water and minerals with the whole thallus surface. The activity levels of 137Cs in lichen in BiH in 1985 were from 397 to 696 Bq/kg. The average activity level of 134+137Cs in lichen of the Evernia prunastri species in the first half of 1987 was 10161 Bq/kg, and 13610 Bq/kg in the second half of the same year. In lichen of the Cetraria islandicaspecies in the second half of 1987 the activity level was 10392 Bq/kg. In the period 1986-2015 the activity levels of 137Cs in investigated lichen samples decreased. The average activity level of 137Cs in Hypogimnia physodeslichen species collected in 2010 in NP Djerdap was 150 Bq/kg, while in 2015 it was 128 Bq/kg. Activity levels of 137Cs have dropped to levels before the Chernobyl accident so no new pollutions with this isotope have occurred.Article is part of: [http://vinar.vin.bg.ac.rs/handle/123456789/8230

Radioactivity in moss and lichen collected in 2015 from NP Djerdap

U radu su prikazani nivoi aktivnosti prirodnih radionuklida (40K, 226Ra, 232Th, 238U) i veštački proizvedenog 137Cs u uzorcima mahovina (28) i lišajeva (17) sakupljenim na teritoriji Nacionalnog parka Đerdap u maju 2015. godine. U svim uzorcima mahovina i lišajeva utvrđeno je prisustvo radionuklida. Dobijeni rezultati upućuju na zaključak da su mahovine i lišajevi dobri biomonitori i bioindikatori radiozagađenja životne sredine, kao i da je neophodno pratiti nivoe aktivnosti radionuklida u njima zbog mogućeg radijacionog rizika organizama koji ih koriste za ishranu ili upotrebljavaju za neku drugu svrhu.Activity levels of natural (40K, 226Ra, 232Th, 238U) and artificially produced 137Cs radionuclides in moss (28) and lichen (17) samples collected on the territory of the Djerdap national park in May 2015 are presented in this work. Radionuclide presence was established in all moss and lichen samples. The obtained results indicate that moss and lichen are good bioindicators of radio-pollution of the environment. It is necessary to monitor activity levels of radionuclides in moss and lichen due to possible radiation risks of organisms consuming them as food or using them for other purposes

Hidrotermalna sinteza katodnog materijala LiFePO4 u prisustvu organske komponente

Katodni materijal LiFePO4 u poslednje vreme privlači veliku pažnju zbog svojih dobrih osobina kao što su visok teorijski kapacitet, stabilnost, niska toksičnost i niska cena. Glavni nedostatak ovog materijala je njegova niska elektronska i jonska provodljivost. U ovom radu LiFePO4 je sintetisan hidrotermalnim postupkom polazeći od vodenih rastvora LiOH, FeSO4 i H3PO4 uz dodatak organske komponente polivinil pirolidona. Nakon hidrotermalne sinteze prah je tertiran na 500oC u blagoj redukcionoj atmosferi. Strukturne i morfološke osobine dobijenog praha LiFePO4 su karakterisane difrakcijom x-zraka, skanirajućom elektronskom mikroskopijom i laserskim analizatorom veličine čestica. Elektrohemijske osobine materijala su ispitane galvanostatskim punjenjem i pražnjenjem

Lichen - bioindicators of radioactive pollution of the environment

Tkivo lišajeva odražava elementarni sastav životne sredine, pa su oni dobri bioindikatori i biomonitori zagađenja životne sredine, jer nemaju formiran koren, list, stablo, kutikulu i stome, a vodu i mineralne materije upijaju celom površinom talusa. Nivoi aktivnosti 137Cs u lišajevima BiH 1985. godine bili su od 397 do 696 Bq/kg. Srednji nivo aktivnosti 137Cs u lišajevima vrste Evernia prunastri u prvoj polovini 1987. godine je bio 10161 Bq/kg, odnosno, 13610 Bq/kg u drugoj polovini iste godine, a u lišajevima vrste Cetraria islandica je u drugoj polovini 1987. godine bio 10392 Bq/kg. U periodu 1986-2015. godina, nivoi aktivnosti 137Cs u ispitivanim uzorcima lišajeva opadaju. Srednji nivo aktivnosti 137Cs u lišajevima vrste Hypogimnia physodes sakupljenim 2010. godine u NP Đerdap bio je 150 Bq/kg, a 2015. godine 128 Bq/kg. Nivoi aktivnosti 137Cs su u nivoima pre akcidenta u Černobilju (1986. god), tj. novih zagađenja ovim izotopom nije bilo.Lichen tissue reflects the elementary composition of the environment. They are good bioindicators and biomonitors of environment pollution as they do not have a formed root, leaves, trunk, cuticula and stoma and they absorb water and minerals with the whole thallus surface. The activity levels of 137Cs in lichen in BiH in 1985 were from 397 to 696 Bq/kg. The average activity level of 134+137Cs in lichen of the Evernia prunastri species in the first half of 1987 was 10161 Bq/kg, and 13610 Bq/kg in the second half of the same year. In lichen of the Cetraria islandicaspecies in the second half of 1987 the activity level was 10392 Bq/kg. In the period 1986-2015 the activity levels of 137Cs in investigated lichen samples decreased. The average activity level of 137Cs in Hypogimnia physodeslichen species collected in 2010 in NP Djerdap was 150 Bq/kg, while in 2015 it was 128 Bq/kg. Activity levels of 137Cs have dropped to levels before the Chernobyl accident so no new pollutions with this isotope have occurred.Article is part of: [http://vinar.vin.bg.ac.rs/handle/123456789/8230