Natural and artificial (90Sr) radionuclides in some carbonated mineral waters used in Serbia

A radiological characterization of 7 different carbonated mineral water samples collected in the local supermarkets in the area of Belgrade (produced in Serbia) was carried out. Analysis included determination of gross alpha and gross beta activities. The obtained results showed that the natural activity concentrations of alpha and beta emitting radionuclides in carbonated mineral water samples were within World Health Organization recommended levels, except for the Heba Strong and Kiseljak samples where the beta activity exceeds 1 Bq/L. For these two water samples gamma spectrometry analysis was performed as well as determination of 90Sr by oxalic method. The instrumentation used to count the gross alpha and gross beta activities, as well as for 90Sr, was a/b low level proportional counter Thermo Eberline FHT 770 T. Gamma spectrometric measurements were performed using a HPGe Canberra detector with a counting efficiency of 20%. The annual effective dose equivalent due to ingestion of investigated waters was calculated for age group >17, and obtained values are lower than 0.1 mSv recommended reference level. Finally, a comparison of the investigated waters with worldwide data was made. [Projekat Ministarstva nauke Republike Srbije, br. III43009

Multicomponent Modelling Kinetics and Simultaneous Thermal Analysis of Apricot Kernel Shell Pyrolysis

Apricot kernel shells are naturally available source of biomass with potential for conversion to clean energy through a thermo-chemical process such as pyrolysis. To facilitate further process development, an advanced mathematical model which represents the process kinetics is developed and validated on the thermal decomposition studies using simultaneous thermal analysis, over a temperature range of 30-900 °C, at four heating rates of 5, 10, 15 and 20 °C min−1, under argon atmosphere. Model-free analysis and numerically developed methods were utilized for determination of effective activation energies, pre-exponential factors and the fractional contribution. A novel approach is introduced in order to determine actual pseudo-components of studied biomass that are included in its composition. The comparative study of the obtained kinetic results was also presented. The results obtained strongly indicated that the pseudo-component reaction modelling method could be employed to predict the experimental devolatilization rate and biomass composition with a high likelihood of success

Absenteeism due to rheumatic diseases in Osijek a 17-year follow-up

Reumatske bolesti predstavljaju značajan socijalno-medicinski problem čije se dimenzije danas vođenom evidencijom ne mogu u cijelosti sagledati. Godišnje se kod liječnika opće medicine liječi 8 500 do 17 500 stanovnika zbog reumatskih bolesti, a udio radnika u tom broju je značajan (3 800 do 8 200). U strukturi morbiditeta reumatske bolesti su stalno na trećem mjestu i čine 7,9 do 11,1% ukupnog morbiditeta. U strukturi ukupnog apsentizma reumatske bolesti zauzimaju drugo mjesto pokazujući izrazitu tendenciju rasta u zadnjih pet godina (stopa s 9,8 u 1978. godini raste na 15,6% u 1982. god). Na 100 zaposlenih radnika dolazi 150 dana bolovanja u 1976. god. a čak 340 u 1982. godini. Prosječna dužina bolovanja po jednom oboljelom radniku jasno .raste (1976. god. npr. iznosi 17,8 a 1982. god. 27,5 dana). Danas su već općepoznati institucijski oblici zdravstvene zaštite radnika (primarna i tzv. specifična zdravstvena zaštita) i uhodane metode administrativnog praćenja morbiditeta li apsentizma. Podaci nalažu prelazak iz faze praćenja na fazu svjesnog uticaja na smanjenje prevalencije reumatskih bolesti. To se ne može postići bez primjene dispanzerske metode rada (dakle kontinuirane, sveobuhvatne i prije svega aktivne zaštite zdravih i bolesnih) posebno u okviru radne organizacije ili. već na nivou primame zdravstvene zaštite. Utjecaj nepovoljnih faktora radne sredine na nastajanje mnogih reumatskih oboljenja je dobro poznat i samo dispanzerski metod rada omogućava orijentaciju na primarnu prevenciju. Prikazan je morbiditet i apsentizam tokom proteklih 17 godina i dati su prijedlozi koncepta rada primame zdravstvene zaštite u zdravstvenoj zaštiti oboljelih od reumatskih bolesti.Rheumatic diseases represent a considerable social and medical problem. Their dimensions are hard to perceive with the sort of evidence we have today. General practitioners provide treatment to about 8 500-14 500 patients yearly. A considerable number of these patients belong to active working population (3 800-8 200). From the structure of morbidity data in general rheumatic diseases appear to be constantly the third with a percentage of 7.9-11.1. In the overall absenteeism rate rheumatic diseases occupy the second place with a steady tendency of growth m the past five years (9.8% in 1978, 15.6% in 1982). In 1976 the number of days of sick leave because of rheumatic diseases was 150 (average 17.8 days) to every 100 workers and in 1982 this number rose to 340 (average 27.5 days)

Gamma Radiation Absorption Characteristics of Concrete with Components of Different Type Materials

Nuclear facilities as nuclear power stations, nuclear research reactors, particle accelerators and linear accelerator in medical institution using concrete in building construction. The different type materials of the aggregate as component of concrete were analyzed to provide radiation protection. The energy deposited the transmission factor and the mass attenuation coefficients in ordinary and barite concretes have been calculated with the photon transport Monte Carlo software. The numerical simulations results show that using barite as an aggregate in the concrete is one of the solutions for gamma ray shielding. Thereat, it is shown non-destructive method for determining the gamma radiation absorption characteristics of concrete.11th Annual Conference of the Materials-Research-Society-of-Serbia (YUCOMAT 2009), Aug 31-Sep 04, 2009, Herceg Novi, Montenegr

Exploring the impact of calcination parameters on the crystal structure, morphology, and optical properties of electrospun Fe 2 TiO 5 nanofibers

Nanostructured Fe2TiO5 (pseudobrookite), a mixed metal oxide material holds significant promise for utilization in energy and environmental applications. However, its full application is still hindered due to the difficulty to synthesize monophasic Fe2TiO5 with high crystallinity and a large specific surface area. Herein, Fe2TiO5 nanofibers were synthesized via a versatile and low-cost electrospinning method, followed by a calcination process at different temperatures. We found a significant effect of the calcination process and its duration on the crystalline phase in the form of either pseudobrookite or pseudobrookite–hematite–rutile and the morphology of calcined nanofibers. The crystallite size increased whereas the specific surface area decreased with an increase in calcination temperature. At higher temperatures, the growth of Fe2TiO5 nanoparticles and simultaneous coalescence of small particles was noted. The highest specific surface area was obtained for the sample calcined at 500 °C for 6 h (SBET = 64.4 m2 g−1). This work opens new opportunities in the synthesis of Fe2TiO5 nanostructures using the electrospinning method and a subsequent optimized calcination process for energy-related applications

Monte Carlo Analysis of the Influence of Different Packaging on MOSFET Energy Response to X-rays and Gamma Radiation

Radiation sensing MOSFETs have found numerous applications as detectors or device components in radiation fields used in nuclear industry, medical applications and space research. Monte Carlo simulations of MOSFET energy response to X-ray and gamma radiation for different packaging were performed. The photon transport Monte Carlo software FOTELP-2K10 has been adapted to obtain the energy deposited in MOSFET structure with microscopic dimensions. In this work the ratio between values of total energy deposited in the sensitive volume (thick SiO2 layer) for cases of MOSFET structure with and without package lid is presented. For this purpose is defined the shielding energy dependence factor (SDEF), and gave its value for kovar and Ti-24Al-11Nb and Ti-13Nb-13Zr alloys as lid materials

Radioaktivnost u životnoj sredini južne Srbije na lokacijama na kojima je korišten osiromašeni uran

In the 1999 bombing of the Federal Republic of Yugoslavia, NATO forces used ammunition containing depleted uranium. The cleaning of depleted uranium that followed was performed in southern Serbia by the Vinča Institute of Nuclear Sciences between 2002 and 2007 at the locations of Pljačkovica, Borovac, Bratoselce, and Reljan. This paper presents detailed results of radioactivity monitoring four years after cleaning (2011), which included the determination of gamma emitters in soil, water, and plant samples, as well as gross alpha and beta activities in water samples. The gamma spectrometry results showed the presence of natural radionuclides 226Ra, 232Th, 40K, 235U, 238U, and the produced radionuclide 137Cs (from the Chernobyl accident). In order to evaluate the radiological hazard from soil, the radium equivalent activity, the gamma dose rate, the external hazard index, and the annual effective dose were calculated. Considering that a significant number of people inhabit the studied locations, the periodical monitoring of radionuclide content is vital.U napadu na Saveznu Republiku Jugoslaviju 1999. godine NATO-ove su snage koristile municiju s osiromašenim uranom. Od 2002. do 2007. Laboratorij za zaštitu od zračenja i zaštitu životne sredine Instituta Vinča proveo je akciju čišćenja osiromašenog urana na lokacijama Pljačkovica, Borovac, Bratoselce i Reljan. U ovom se radu iznose detaljni rezultati praćenja radioaktivnosti u južnoj Srbiji četiri godine nakon spomenute akcije čišćenja (2011), koji uključuje određivanje gama zračenja u uzorcima zemljišta, vode i biljki te određivanje ukupne alfa i beta aktivnosti u uzorcima vode. Rezultati gama spektrometrije pokazali su prisutnost prirodnih radionuklida: 226Ra, 232Th, 40K, 235U, 238U i proizvedenog radionuklida 137Cs. Za procjenu radijacijskog rizika iz zemljišta izračunati su ekvivalent radija, brzina apsorbirane doze gama zračenja, indeks radijacijskog rizika uslijed vanjskog izlaganja i efektivna doza zračenja. Imajući u vidu da na ispitivanim područjima živi znatan broj ljudi, iznimno je važno da se ondje periodično prati sadržaj radionuklida