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This paper aims to estimate a potential radiological risk from different kinds of coals used for domestic heating in Serbia, by measuring the activity concentration of radionuclides and radon exhalation rate. The obtained radon mass exhalation rate ranges from (5.3 ± 3.1) mBqkg–1s–1 to (70.3 ± 9.4) mBqkg –1s–1 and was highest for lignite type of coal. It is estimated that coal stored in the basement could contribute up to 50 Bqm–3 of indoor radon concentration at the ground level. Activity concentrations of 226Ra, 232Th, 40K, 238U, 235U, and 210Pb in analysed coal samples agree with previously reported concentrations of coal used in Serbia. The values of radium equivalent concentration and external hazard index indicate that the used coal does not represent a significant radiation hazard.

This pa per aims to es ti mate a po ten tial ra dio log i cal risk from dif fer ent kinds of coals used for do mes tic heat ing in Ser bia, by mea sur ing the ac tiv ity con cen tra tion of radionuclides and ra don ex ha la tion rate. The ob tained ra don mass ex ha la tion rate ranges from (5.3 +/- 3.1) mu Bqkg-1s-1 to (70.3 +/- 9.4) mu Bqkg -1s-1 and was high est for lig nite type of coal. It is es ti mated that coal stored in the base ment could con trib ute up to 50 Bqm-3 of in door ra don con cen tra tion at the ground level. Ac tiv ity con cen tra tions of 226Ra, 232Th, 40K, 238U, 235U, and 210Pb in ana lysed coal sam ples agree with pre vi ously re ported con cen tra tions of coal used in Ser bia. The values of radium equivalent concentration and external hazard index indicate that the used coal does not represent a significant radiation hazard.

This paper aims to estimate a potential radiological risk from different kinds of coals used for domestic heating in Serbia, by measuring the activity concentration of radionuclides and radon exhalation rate. The obtained radon mass exhalation rate ranges from (5.3 ± 3.1) mBqkg–1s–1 to (70.3 ± 9.4) mBqkg –1s–1 and was highest for lignite type of coal. It is estimated that coal stored in the basement could contribute up to 50 Bqm–3 of indoor radon concentration at the ground level. Activity concentrations of 226Ra, 232Th, 40K, 238U, 235U, and 210Pb in analysed coal samples agree with previously reported concentrations of coal used in Serbia. The values of radium equivalent concentration and external hazard index indicate that the used coal does not represent a significant radiation hazard.

Cementation is the baseline technology for conditioning of low to intermediate level radioactive waste. Geopolymers, a class of alkali activated binders, are a promising new material for radioactive waste treatment. Coal fly-ash based geopolymers are a low-cost, low greenhouse gas footprint alternative to metakaolin based materials. Both the grouting of sludge/powders/liquids and encapsulation of solids/compacted waste rely on the grout maintaining optimal flow (rheological properties) during the mixing and pouring operations, and achieving a set leading to proper long term solidification (mechanical properties). The initial and final setting time for fly-ash geopolymer paste, based on the SRPS EN 196-3 standard, has been measured upon irradiation by gamma rays in a 60Co reference field positioned with a kerma air rate of 3.42 mGys–1. The binder paste was prepared using fly-ash from the TENT B power plant's electrostatic filters without further sieving, activated by water glass with module 1.5 and mixed with distilled water until a satisfactory flow was obtained, and poured into the sample and control molds. The initial and final setting times for the irradiated sample and non-irradiated control were determined by the Vicat apparatus. The irradiated sample demonstrated an 11 % shorter initial setting time, and 16 % shorter final setting time, compared to the control.

The second most important source of indoor radon, after soil beneath dwelling, is building material. With the increase in environmental awareness and new energy-saving policies, residents tend to replace the existing windows with tighter windows, which leads to a decrease in air exchange rate and consequently an increase in indoor radon concentration. In case of low exchange rates, dose caused by inhalation of radon and its progeny can exceed external dose originating from the radium content in the surrounding building material. In this paper, surface exhalation rates of radon ( 222 Rn) and thoron ( 220 Rn) from typical building materials used for construction and interior decoration of houses in Serbia were investigated. Surface exhalation rate measurements were performed using the closed-chamber method, while concentrations of radon and thoron in the chamber were continuously measured using an active device, RTM1688-2, produced by SARAD® GmbH. Finally, the impact of the replacement of windows on the indoor radon concentration was estimated.

The goal of the nanoparticle synthesis is, first of all, the production of nanoparticles that will be more similar in size and shape. This is very important for the possibility of studying and applying nanomaterials because of their characteristics that are very sensitive to size and shape such as, for example, magnetic properties. In this paper, we propose the shape analysis of the nanoparticles using three shape descriptors – elongation, convexity and circularity. Experimental results were obtained by using TEM images of hematite nanoparticles that were, first of all, subjected to segmentation in order to obtain isolated nanoparticles, and then the values of elongation, convexity and circularity were measured. Convexity C x ( S ) is regarded as the ratio between shape’s area and area of the its convex hull. The convexity measure defines the degree to which a shape differs from a convex shape while the circularity measure defines the degree to which a shape differs from an ideal circle. The range of convexity and circularity values is (0, 1], while the range of elongation values is [1, ∞). The circle has lowest elongation (ε = 1), while it has biggest convexity and circularity values ( C x = 1; C = 1). The measures ε( S ), C x ( S ), C ( S ) proposed and used in the experiment have the few desirable properties and give intuitively expected results. None of the measures is good enough to describe all the shapes, and therefore it is suggested to use a variety of measures so that the shapes can be described better and then classify and control during the synthesis process.

The possibility of retaining Cs+ and Co2+ bound by immobilization processes in the cement matrix is defined as the subject of its investigation: the cement matrix formulation, the water/ cement ratio, the amount of waste, and the porosity of such a structure. Implementing the standard leaching method by Hespe the possibility of comparing different authors’ results was achieved. Diffusion and semi-empirical model were used to investigate the transport phenomenon in order to predict the leaching level for a long period of time. Leaching of Co2+ and Cs+ ions under dynamic conditions immobilized in the cement matrix dynamic conditions decreases with the increase of the sludge content, regarding porosity increase. The effects of the diffusion and surface washing are equalized, and the contribution ofthe matrix dissolution to the Cs + and Co2+ transport in the cement porous media increases, on average, for one order of magnitude. The semi-empirical model gives a better approximation for Co2+ and Cs+ leaching process for the duration ofthe experiment while both models significantly approximate leaching results in dynamic conditions. © 2019, Vinca Inst Nuclear Sci. All rights reserved.

It is well-known that radon is the second important human carcinogen for lung cancer, after smoking. The major sources of indoor radon concentrations are soil and building material. Under certain conditions, a dose received from the inhalation of radon and its progenies can be higher than a dose received from the external exposure due to radium concentration in building materials. In this contribution, the results of the radon and thoron exhalation rate measurement from 9 commonly used building materials are reported. Exhalation rate measurements were performed with accumulation chamber method using active device for measurement of radon concentration. © 2019 RAD Association. All rights reserved.

Geopolymers are a type of alkali activated binders, inorganic aluminosilicate polymers with amorphous cross-linked structure. Fly-ash is produced in abundance during coal firing, and poses an environmental and health risk in untreated powder form. Fly-ash geopolymer presents a sustainable alternative to Portland cement, due to lower net greenhouse gas emissions. Presence of naturally occurring radioactive elements in fly-ash is one of the factors taken into account when estimating the safety of fly-ash based building materials. Radon, a radioactive noble gas originating from the decay of radium, can leave the material and contribute to internal dose in closed spaces, so radon exhalation is of special interest. Radon exhalation for a standard sample of fly-ash geopolymer mortar was measured.

It is indicated that the exposure to radon originating from the building materials is not negligible and the radon exhalation measurement should get more attention in the future. The experience with four different methods of the exhalation measurement, established in our laboratory for the purpose of the intercomparison is reported. Additionally, a comparison of advantages and disadvantages of used methods is discussed.

The aim of this paper is to consider and analyze design of capacitive voltage divider for measuring ultrafast voltage occurrence. Measuring pulse voltages by means of a capacitive divider in nanosecond range is affected by problems related to the construction of the divider and materials used. However, an appropriate constructive solution could minimize the budget of measuring uncertainty of the measurement pertaining to parasitic inductivity and capacitance. Consequently, the right selection of dielectric materials could offset the effects of high-voltage and low-voltage frequency characteristics of the capacitor. Four types of capacitive dividers have been constructed for the purpose of this paper. The high-voltage capacitor of each divider is a gas capacitor (intended to avoid both electrostatic and electrodynamic influence on measurement uncertainty). Ultrafast pulse response is measured by dividers constructed in this way, and compared with the corresponding response obtained from numerical simulations.

It is well-known that radon is the second important human carcinogen for lung cancer, after smoking. The major sources of indoor radon concentrations are soil and building material. Under certain conditions, a dose received from the inhalation of radon and its progenies can be higher than a dose received from the external exposure due to radium concentration in building materials. In this contribution, the results of the radon and thoron exhalation rate measurement from 9 commonly used building materials are reported. Exhalation rate measurements were performed with accumulation chamber method using active device for measurement of radon concentration. © 2019 RAD Association. All rights reserved.

Gamaspektrometrija je jedna od najčešće korišćenih metoda za kvalitativno i kvantitativno određivanje sadržaja radionuklida u zemljištu i drugim uzorcima iz životne sredine. Meren je 31 uzorak zemljišta sa teritorije opštine Aleksandrovac, pri čemu su za svaki uzorak korišćene dve različite geometrije (cilindrična kutijica i marineli posuda). Određene su specifične aktivnosti radioizotopa uranovog i torijumovog niza, kao i 235U, 40K i 137Cs. Uzorci zemlje u geometriji cilindrične kutijice mereni sa na dva HPGe detektora različitih efikasnosti i karakteristika, dok su uzorci u marineli posudi mereni samo na jednom HPGe detektoru. U radu su prikazani rezultati poređenja specifičnih aktivnosti istih radionuklida dobijenih merenjem uzoraka u različitim geometrijama na istom HPGe detektoru kao i uzoraka u geometriji cilindrične kutijice merenih na različitim detektorima. Analizirani su uzroci nastalih varijacija., Gamma ray spectrometry is an analytical method that allows the identification and quantification of gamma emitting radioisotopes in soil and other environmental samples. 31 samples of soil were collected from different location in the territory of Aleksandrovac municipality. All soil samples were dried, milled and sealed in two different geometries (500 ml Marinelli beaker and 125 ml cylindrical boxes) and stored for six weeks in order to reach radioactive equilibrium between 226Ra and its descendants. All samples stored in cylindrical boxes were measured by means of two coaxial semiconductor HPGe detectors with different characteristics, while samples stored in Marinelli beakers were measured only by means of one coaxial semiconductor HPGe detector. The activity concentrations of radionuclides 40K, 137Cs, 235U, 226Ra, 238U and 228Ac in all soil samples were determined. Variations in specific activities determination for different geometries measured using one of the detectors, as well as for cylindrical box geometry measured using both detectors, are presented in this paper. The causes of these variations are analyzed.

U ovom radu su sprovedena eksperimentalna istraživanja odziva ESAPMOS4 RADFET komponenti u polju gama zračenja 60Co kada su inkorporirane u dva različita merna sistema, u statičkom i dinamičkom on-line mernom sistemu. Značaj istraživanja se ogleda u uspostavljanju metoda kojim se ostvaruje eksperimentalna karakterizacija RADFET strukture u poljima jonizujućeg zračenja s obzirom da se koristi on-line merna tehnika određivanja zavisnosti napona praga RADFET od promene apsorbovane doze zračenja u dinamičkom režimu rada digitalnog mernog sistema. To znači da se kontinualno sprovodi registrovanje vrednosti električne veličine kojom se prati odziv MOSFET-a u tačno zadatim vremenskim intervalima dok traje ozračivanje komponente, što ranije nije bio slučaj u statičkom režimu merenja promene napona praga. Razlika između izmerenih odziva za dva različita sistema merenja je bila u granicama eksperimentalne merne nesigurnosti od 2% do 5% ., In this paper, experimental responses to ESAPMOS4 RADFET components in the field of gamma radiation 60Co were performed when incorporated into two different measurement systems, in a static and dynamic on-line measurement systems. The significance of the research is reflected in the establishment of methods for achieving the experimental characterization of the RADFET structure in ionizing radiation fields since the use of an on-line measuring technique for determining the dependence of the RADFET threshold voltage on changing the absorbed dose of radiation in the dynamic regime of the digital measuring system is used. This means that continuously the registration of an electrical quantity value to monitor the response of the MOSFET at precisely defined time intervals while the component is irradiated, which was not the case before in the static measurement mode of change the threshold voltage. The difference between the measured responses for two different measurement systems was within the experimental measurement uncertainty of 2% to 5%.

U radu je merena ekshalacija radona iz bigra iz Niške Banje poznatom po povišenoj koncentraciji 226Ra. Bigar zbog svoje velike poroznosti i visoke koncentracije radijuma je idealan materijal za testiranje parametara od kojih zavisi brzina ekshalacije. U radu je razmatrana zavisnost ekshalacije u odnosu na vlažnost kao i na sprašenost uzorka. Brzina ekshalacije je merena metodom zatvorene komore, a sama koncentracija radona aktivnim uređajem. Dobijeni rezultati ukazuju da brzina ekshalacije raste sa povećanjem vlažnosti uzorka i smanjenjem veličine zrna., In this contribution, radon exhalation rate from travertine originating from Niška Banja, Serbia was measured. This particular travertine, with a high 226Ra concentration and high porosity, is ideal for testing various parameters that can influence radon exhalation rate. The radon exhalation rate was investigated for different sizes of grains. Grain sizes were dived into 4 groups: 1) 2.1 - 1.6 mm, 2.) 1.6 - 1.2 mm, 3.) 1.2 - 0.7 mm i 4.) < 0.7 mm. Influence of the humidity on radon exhalation rate was also investigated. Samples with the smallest grain size were exposed to 3 different levels of humidity (dry sample, and two samples in which water content was around 10% and 20% of the mass of dry sample. An accumulation chamber method with an active device RTM1688-2 was used to estimate radon exhalation rate from continuous measurement of radon in the chamber. Obtained results indicate that radon exhalation rate is increasing with an increase of humidity of the sample and with an decrease of grain size.

Prikazan je pregled najnovijeg gama metoda za merenje ekshalacije radona iz građevinskih materijala, koji pored ekshalacije omogućava merenje faktora emanacije i merenje difuzione dužine radona u datom materijalu, što nije moguće u standardnim merenjima ekshalacije radona. Takođe su prikazana i još tri standardna metoda merenja ekshalacije radona i dato je uporedno objašnjene prednosti i mana ovih metoda. Biće dat i pregled dosadašnjih merenja u Srbiji., A review of a new radon exhalation measurement method is presented. This method provides also a measurement of the radon diffusion length and the radon emanation coefficient, which is not possible by standard radon exhalation measurement methods. Besides, three standard radon exhalation measurements are presented: closed chamber with an active instrument, closed chamber with a solid state nuclear track detector and a charcoal canister method. An intercomparison of advantages and disadvantages is also given. A short review of previous measurements of radon exhalation from comercial building materials in Serbia will be given in the presentation.

With an increase in the awareness of the need to save energy, residents tend to live in dwellings with increasingly tight windows and doors, thus reducing the ventilation rate of indoor air which leads to an increased accumulation of radon indoors. Having in mind that a dose from an exposure to inhaled radon and its progenies can be higher than a dose received from radium in building materials, it is suggested that radon exhalation measurements should receive due attention. In this contribution, the authors compare results gathered using a few methods for radon exhalation measurement and discuss its merits and demerits.

In this paper we give an overview of radiation effects in emergent, non-volatile memory technologies. Investigations into radiation hardness of resistive random access memory, ferroelectric random access memory, magneto-resistive random access memory, and phase change memory are presented in cases where these memory devices were subjected to different types of radiation. The obtained results proved high radiation tolerance of studied devices making them good candidates for application in radiation-intensive environments.

The sorption properties of waste facade, brick, and asphalt sample towards Sr(II), Co(II), and Ni(II) ions from single and multicomponent solutions were investigated. The highest sorption capacity was found for Ni(II) ions, while the most effective sorbent was facade. Simplex Centroid Mixture Design was used in order to investigate the sorption processes of ions from solutions with different composition as well as the competition between the cations. Based on the statistical analysis results, the equations for data modeling were proposed. According to the observations, the investigated solid matrices can be effectively used for the liquid radioactive waste treatment. Furthermore, the applied methodology turned out to be an easy and operational way for the investigations of multicomponent sorption processes.

Masena spektrometrija sa Knudsen-ovom ćelijom (eng. Knudsen cell mass spectrometry, KCMS, odnosno masena spektrometrija sa efuzionom ćelijom ili masena spektrometrija molekulskog snopa) je metoda kojom se proučavaju osobine neorganskih supstanci, poput metala i njihovih legura (posebno oksida, sulfida, selenida, telurida i halogenida). Ova metoda koristi se i za dobijanje, analizu i karakterizaciju klastera, grupe konstituenata (atoma, molekula) međusobno povezanih vezama različite jačine. KCMS-om mogu se dobiti i informacije o kvalitativnom sastavu gasovite faze odnosno o identitetu molekula koji nastaju u hemijskim reakcijama pod neravnotežnim uslovima, kao i uticaju vremena, temperature i gustine fluksa upadnih čestica na brzinu stvaranja novih molekula, parcijanom pritisku svih pojedinačnih gasovitih komponenti, promenama parcijalnog pritiska sa temperaturom, kao i kinetici procesa isparavanja. Takođe, koristi se i za izračunavanje parcijalnih pritisaka pojedinačnih komponenti u zasićenoj pari korišćenjem jednačina koje povezuju jonske intenzitete i parcijalne pritiske, povezivanjem eksperimentalno određenih veličina, inteziteta jona i temperature u ćeliji sa pritiskom zasićene pare ispitivane supstance.Postojanje klastera kalijum-halogenida (KnX, X = F, Cl, Br, I) je teorijski opisano, mada do sada nisu eksperimentalno dobijeni usled velikog rasipanja jona, šuma i gubitka određene količine neutrala koji nastaju u samoj klasičnoj Knudsen-ovoj efuzionoj ćeliji, što, između ostalog, otežava identifikaciju spektra. Stoga je, u okviru ove doktorske disertacije, predloženo novo konstrukciono rešenje za primenu Knudsen-ove efuzione ćelije koje se odnosi na promenu položaja ćelije u odnosu na jonsku komoru, kao i drugačiju tehniku jonizacije – tehnika površinske ili termalne jonizacije, čime je omogućena sinteza, karakterizacija i određivanje svojstava KnX klastera. Naime, konstruisanje, na ovaj način, stabilnog izvora jona klastera, rezultiralo je u direktnom stvaranj, Knudsen cell mass spectrometry, KCMS, or mass spectrometry with effusion cell or molecular beam mass spectrometry, is a method for investigating properties of inorganic substances such as metals and their alloys (in particular oxide, sulfide, selenide, telluride and halogenide). This method is also used for the synthesis, analysis and characterization of clusters, groups of constituents (atoms, molecules) connected with bounds of different strength. Furthemore, it provides the information about the vapor phase qualitative composition or identity of the molecules that are formed in chemical reactions under equilibrium conditions, as well as the effects of time, temperature and incident particles flux density on generating speed of new molecules, partial pressure of individual gaseous components, changes in partial pressure with temperature, as well as the kinetics of the process of evaporation. It is also applied to calculate the partial pressures of the individual components in the saturated steam using equations that connect ion intensities and partial pressures, connecting experimentally determined size, intensity and temperature of ions in the cell with the saturated vapor pressure of tested substance.The existence of potassium halide clusters (KnX, X = F, Cl, Br, I) is theoretically described, although, till now, they have not been experimentally obtained due to the large ion spreading, noise, and loss of a certain amount of neutrals generated by common Knudsen effusion cell, which, among the other things, makes the identification of the spectrum difficult. Therefore, this doctoral dissertation, proposed a new structural solution for Knudsen's effusion cell implementation that resulted in changing the position of the cell in relation to the ion chamber, as well as the use of different ionization technique, the technique of surface or thermal ionization, enabling to synthesize, characterize and determine properties of KnX clusters. This modification provided, thr

Predmet istraživanja ove doktorske disertacije je izučavanje uticaja ulaznih podataka na polja koncentracija zagađujućih materija u donjem graničnom sloju atmosfere dobijenih primenom matematičkih modela kao i usložnjavanje matematičkog modela atmosferske disperzije Gausovog tipa, čiji je rezultat generalisan Gausov disperzioni model. Cilj istraživanja u ovom radu je realizacija i primena kompleksnog matematičkog difuzionog modela, koji uzima u obzir složene atmosferske procese u sloju mešanja, kao i razrađena procedura za pripremu ulaznih podataka, koji omogućavaju praćenje rasprostiranja zagađujućih materija u okolini industrijskih i nuklearnih izvora na rastojanjima do 10-20 km, gde su koncentracije zagađujućih materija iz tih izvora obično najveće i gde se dobijaju prve informacije važne za ranu najavu akcidenata i pokretanje kontramera. Pored navedenog cilj je i verifikacija matematičkog modela pisanog u FORTRAN programskom jeziku (NFS-Vinca) preko meteoroloških podataka koji su dobijeni u realnom vremenu, kao i procena rasprostiranja polutanata na osnovu idealizovane situacije sa zadatim vetrom i klasama stabilnosti.Istraživanja u okviru doktorske disertacije polaze od hipoteze da koncentracije zagađujućih materija koje se emituju u atmosferu iz veštačkih izvora zavise od karakteristika izvora, atmosferskih procesa u donjem graničnom sloju atmosfere, tzv. sloju mešanja, karakteristika tla i fizičko hemijskih karakteristka zagađujućih materija. Kod nuklearnog postrojenja modelovana je koncentracija radioaktivnosti u vazduhu sledećih radionuklida: 137Cs, 90Sr, 60Co, 154Eu. Kod industrijskog postrojenja određivan je nivo koncetracije PM10.U prvom delu rada, matematičkim modelom su dobijene prosečne godišnje koncentracije aktivnosti u vazduhu, koncentracije suve i vlažne depozicije kao i ukupna godišnja doza koju bi primio hipotetički stanovnik u blizini nuklearnog reaktora. Rezultati modelovanja su upoređeni sa vrednostima koncentracije radioaktivnosti iz IAEA (I, The subject of this doctoral dissertation was the influence of the input data on the pollutant concentration in the lower atmospheric boundary layer obtained by mathematical model, which was the result of generalized Gaussian dispersion model. The aim was implementation of complex mathematical diffusion model and development procedures which enable the monitoring of dispersion of pollutants in the environment of industrial and nuclear power plants within 10-20 km, where the concentration of pollutants from these sources is usually the highest, and also for early warning for accidents and countermeasures. In addition is the verification of the mathematical model in FORTRAN programming language (NFS-Vinca) through meteorological data obtained in real time, as well as the evaluation of dispersion of pollutants on the basis of idealized situations specified with wind classes and stability.Research in this dissertation is based on the hypothesis that the concentrations of pollutants emitted into the atmosphere from artificial sources depend on the characteristics of the sources of atmospheric processes in the lower atmospheric boundary layer, soil characteristics and the physical and chemical characteristics of pollutants. For the nuclear power plant, radioactivity concentration of the following radionuclides 137Cs, 90Sr, 60Co, 154Eu was determined. For thermal power plant the concentration level of PM10 was measured.The air pollution dispersion model is based on average annual activity concentration in the air, deposition on soil and field of total annual dose to a hypothetical resident contaminated by air in the vicinity of a nuclear reactor. The results of modeling were compared with values from an IAEA publication for a given scenario of radionuclide emission to the atmospheric boundary layer. Due to small differences in the results, compared to the IAEA recommended model, the model presented in the thesis can be used as a basis for this type of analysis. The maximum

In the era of the energy saving policy (i.e. more air tight doors and windows), the radon exhaled from building materials tends to increase its concentration in indoor air, which increases the importance of the measurement of radon exhalation from building materials. This manuscript presents a novel method of the radon exhalation measurement using only a HPGe detector or any other gamma spectrometer. Comparing it with the already used methods of radon exhalation measurements, this method provides the measurement of the emanation coefficient, the radon diffusion length and the radon exhalation rate, all within the same measurement, which additionally defines materials radon protective properties. Furthermore it does not necessitate additional equipment for radon or radon exhalation measurement, which simplifies measurement technique, and thus potentially facilitates introduction of legal obligation for radon exhalation determination in building materials. (C) 2016 Elsevier Ltd. All rights reserved.

We propose using a new circularity measure, and an ellipticity measure. Observing an example of hematite (alpha-Fe2O3) nanoparticles, we compared and discussed a new circularity measure, with a standard measure. It has been shown that using the new measure gives better results when working with low-quality images or with low-resolution images. Using the same images modified ellipticity measure has also been discussed. We have analyzed the problems arising from computing the elongation of a shape. We have shown that the standard approach to compute elongation is not appropriate for some particles. We presented the application of the modified approach to solve this problem. (C) 2016 Elsevier Ltd. All rights reserved.

For the first time, particle shape analysis of silica coated iron oxide (maghemite/magnetite) nanoparticle clusters (core-shell nanostructures) is discussed using computational methods. We analyzed three samples of core-shell nanostructures synthesized with different thickness of the silica shell. A new computational method is presented and successfully applied to the segmentation of the core-shell nanoparticles, as one of the main problems in image analysis of the TEM micrographs. We have introduced the circularity coefficient, marked with k(circ) and defined as the ratio of circularity measure C-2(S) of nanoparticles core and circularity measure core-shell nanoparticles in order to answer the question how the shell affects the overall shape of the final core-shell structure, with respect to circularity. More precisely, the circularity coefficient determines whether the circularity of the core-shell nanoparticle is higher, lower or equal to the circularity of the core. We have also determined the shells share in the overall area of the core-shell nanoparticle. The core-shell nanoparticle clusters here investigated exhibit superparamagnetic properties at room temperature, thus emphasizing their potential for use in practical applications such as in biomedical and particle separation. We show that the saturation magnetization strength can be easily adjusted by controlling the thickness of the silica shell. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Naturally occurring radionuclide (uranium, actinium and thorium series and 40K) are widespread in the environment. In addition, significant amount of 137Cs may also be present in the soil as a result of accidents, such as Chernobyl accident. Thus, monitoring of radionuclides content in soil is of great importance. Aleksandrovac is small town in the western part of central Serbia and Župa is identified as the administrative territory of Aleksandrovac municipality. Nature of Aleksandrovačka Župa is under the long-lasting influence of anthropogenic factors, and therefore dominates altered natural landscape. Activity concentration of 226Ra, 232Th, 40K and 137Cs in 26 soil samples collected from different location in the territory of Aleksandrovačka Župa were determined and presented. All soil samples were milled and sealed in 0.5 l Marinelli beakers, and stored for six weeks in order to reach radioactive equilibrium between 226Ra and its descendants. All samples were measured by means of coaxial semiconductor HPGe detector (ORTEC GEM-30, 37% relative efficiency and 1.8 keV resolution for 60Co at 1332 keV line). The detector was calibrated using the standards in the same geometry spiked with common mixture of gamma-ray emitters certified by Czech Metrological Institute. The activity concentrations of radionuclides 40K and 137Cs in soil samples were determined directly by analyzing full-energy peaks of their principal energies at 1460.83 keV and 661.66 keV, respectively. The activity of 40K was corrected for the contribution of 228Ac (1459.14 keV). The activity of 226Ra was determined by analyzing full-energy peak at 186.21 keV, corrected for the contribution of 235U (185.72 keV) evaluated via 235U photo-peak at 143.77 keV and additionally approved by analyzing activity concentrations of its descendants (214Bi and 214Pb). Furthermore, the activity concentration of 232Th was determined by using the evaluated activity of its descendants (228Ac, 212Bi, 212Pb, and 208Tl). All

This paper presents an algorithm for the calculation of internal and external doses as an integral part of the mathematical model of atmospheric dispersion. The air pollution dispersion model is used on average annual activity concentration in the air, deposition on soil and field of total annual dose to a hypothetical resident contaminated by air in the vicinity of a nuclear reactor. The results of modeling were compared with values from an IAEA publication for a given scenario of radionuclide emission to the atmospheric boundary layer. Due to small differences in the results, compared to the IAEA recommended model, the model presented in the paper can be used as a basis for this type of analysis.