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[en] The text of a letter dated 8 December 2000 from the Foreign Minister of the Federal Republic of Yugoslavia to the Director General, by which the Federal Republic of Yugoslavia submits an application for membership of the Agency is, at the request of that state, reproduced in the Attachment hereto for the information of Member States
[en] The first step in radon concentration measurement is an inexpensive screening measurement to determine whether a house has a potential for causing high exposures to its occupants. If the obtained result is bellow the screening level (200 Bq/m3), follow-up measurements are probably not needed. Short-term measurement of radon in homes and schools with charcoal canister is easy to perform and it has to be based on standardized protocols to ensure accurate and consistent measurements. The method of measurement is based on radon adsorption on coal and measurement of gamma radiation of radon daughters. Charcoal canisters were placed at distance of 1 m from the floor and the walls. Upon closing the canisters, the measurement was carried out after achieving the equilibrium between radon and its daughters (at least 3 hours) using NaI or HPGe detector. Canisters used for the measurement were calibrated by 226Ra standard in the same geometry. Systematic survey of radon concentration in dwellings was performed in Belgrade in 2016. The charcoal canisters were exposed in the homes, kindergartens and schools. The data resulting from this radon survey merely show a preliminary picture of indoor radon concentration, but the results are in agreement with the previous work and we can conclude that situation is satisfactory. (author).
[en] Evapotranspiration is one of the crucial components of hydrological cycle. The Penman-Monteith method (PM) is recommended as the sole standard method for estimating reference evapotranspiration (ET0). The usage of the PM method is limited in many regions due to the lack of required weather data. In such circumstances, simple Thornthwaite equation is often used to estimate ET0. The main objectives of the present study are (i) to estimate reference evapotranspiration using different Thornthwaite approaches, (ii) to develop optimal adjusted equation, and (iii) to consider the spatial variability of the empirical coefficient(s) of adjusted equation for the study area. In this study, six Thornthwaite approaches were compared to the full set PM equation using weather data from Vojvodina region, Serbia. The original Thornthwaite equation was very poor in estimating ET0 and greatly underestimated PM values at all locations. It can be concluded that an adjustment of the Thornthwaite equation is necessary. The obtained results indicate that ET0 could be estimated from the new Th65 approach (effective temperature, k = 0.65), which reproduced statistical characteristics better compared to other Thornthwaite approaches. The spatial variability of the empirical k coefficient showed that k values varied from 0.62 to 0.69 across the study area with deviations of − 5% to 6% compared to a unique k value of 0.65. These results suggested that single regional k value can be successfully used for estimating ET0.
[en] We have tested value of the product of kerma in air and surface (kerma area product (KAP)) on 31 intra-oral X-ray units at different locations in the Republic of Serbia, in order to optimize the dose for patients. As image receptors are used films of class D, E and F, phosphor plate systems (storage phosphor plate (SPP)) and digital sensors (charged-couple-device (CCD)). The exposure time for each image receptors is given in accordance with the diagnostic requirements for incisors, canines and molars, upper and lower jaw. The measured values for the median molars of the upper jaw, the tested doses ranging from 22.4 to 116.2 mGy cm2. The tested values for film class D, are different compared to other receptors E, F, CCD and SPP, from 5 to 9 times, which is consistent with studies of similar character.(author).
[en] The paper deals with the analysis of the annual indoor radon concentrations variations due to different geological parameters of Sjenica community, Western Serbia. The measured 222Rn concentrations were ranging from 10 to 1130 Bq/m3. In 14% of the buildings, the radon action level of 300 Bq/m3 is exceeded, indicating that Sjenica community could be characterized as a radon priority area. Each of 35 measuring location was georeferenced and corresponding lithostratigraphic units and geological period was assigned. Data were analyzed using the multiple linear regression (MLR) method and two predictive models were developed. The MLR model generated by the geological periods explained 17% of the radon variability while, the better one, was the lithostratigraphic MLR model, which explained 52% of the radon variability. Analysis has shown that lithostratigraphic units are important parameters in the prediction of radon levels. © 2019 Carpathian Journal of Earth and Environmental Sciences.
[en] The rates of radon exhalation from building materials available on the Serbian market were measured using RAD7 device. Fitting the growth curves of radon activity concentration provided the information on radon exhalation rates from the samples. The results were quite low and they ranged from 1.4 to 855 mBq m-2 h-1 for surface exhalation rate and from 1.3 to 11.4 mBq kg-1 h-1 for mass exhalation rate. The effect of moisture on radon exhalation was confirmed. For powdered samples with dimensions smaller than radon diffusion length, the mass exhalation rate is independent of sample mass and its exhalation area. (author)