Search

U bogatoj flori Srbije uspeva veliki broj vrsta lekovitog bilja čiji se sastojci koriste u farmaceutskoj industriji i medicini, kako zvaničnoj tako i narodnoj. Pored toga lekovito bilje se u velikoj meri koristi u svakodnevnoj upotrebi kao neka vrsta napitka. Prirodni radionuklidi (radionuklidi uranovog i torijumovog niza kao i K-40) sastavni su deo naše životne sredine, a kao posledicu nuklearnih akcidenata imamo i prisustvo antropogenih radionuklida, pre svega Cs-137. Masovna upotreba lekovitog bilja predstavlja radijaciono opterećenje za široku populaciju, pa je zbog toga neophodan redovan monitoring. U ovom radu analizirano je 9 vrsta lekovitog bilja sa područja Gučeva (Zapadna Srbija). Specifične aktivnosti prirodnih radionuklida Pb-210 i K-40, kao i Cs-137 određene su merenjem svih uzoraka na poluprovodničkom HPGe spektrometru. Izračunate su godišnje efektivne doze usled ingestije za svaki izmereni radionuklid, i za dve starosne kategorije (uzrast od jedne godine i odrasla osoba). Svi proračuni su zasnovani na pretpostavci da se dnevno pije 200 ml čaja priprepremljenog korišćenjem određene lekovite biljake. Dobijene vrednosti za efektivnu dozu ingestije upućuju na zaključak da svakodnevna upotreba čajeva od lekovitih biljaka sa analiziranog područja ne predstavlja značajan radiološki rizik po zdravlje odrasle osobe, ali je neophodan oprez i obazrivost kada su u pitanju deca., In the rich flora of Serbia, there are a large number of medicinal plants types used in the pharmaceutical industry and medicine. There is also a large percentage of daily use of herbal teas as some kind of beverages. Natural radionuclides (radionuclides of the uranium and thorium series as well as K-40) are an integral part of our environment, and as a consequence of nuclear accidents we also have the presence of anthropogenic radionuclides, primarily Cs-137. The significant use of medicinal plants represent a radiological burden for the general population, so the regular monitoring is needed. In this work, 9 types of medicinal plants from the area of Gučevo (Western Serbia) were analysed. The specific activities of natural radionuclides 210-Pb i 40-K as well as Cs-137 were determined using a semiconductor HPGe spectrometer. Annual effective dose due to ingestion were calculated for each measured radionuclide, and for two age categories (one year old and adult). All calculations are based on the assumption daily consumption of 200 ml of herbal tea. The obtained values for the annual effective dose due to ingestion point to the conclusion that the daily use of medicinal plant teas from the analyzed area does not represent a significant radiological risk for the health of adults, but caution and prudence are necessary when it is about children.

Ensuring confidence in the results of laboratory measurements is an essential assignment regarding quality control. Therefore, taking actions in obtaining valid results is crucial for such a task. In this paper we present the results of the internal quality control of the HPGe detector system. The results were obtained during 2022, in the Laboratory for Nuclear and Plasma Physics of the “Vinca” Institute for Nuclear Sciences, Belgrade, Serbia. Given results show proper use of the detector system and prove the validity of the results.

Ugalj kao fosilno gorivo sadrži brojne prirodne radioaktivne izotope koji pripadaju uranovom i torijumovom nizu, kao i 40K. Najviše se koristi u industriji, kao i u proizvodnji energije. Problem u vezi sa proizvodnjom energije iz uglja je takozvani „energetski otpad“, kao što su pepeo i šljaka, koji predstavljaju nesagorivi i nesagoreli ostatak pri sagorevanja uglja. Ako se pepeo i šljaka odlažu u životnu sredinu, može doći do povećanja i/ili preraspodele prirodnog sadržaja radionuklida. Da bi se utvrdio potencijalni uticaj „energetskog otpada“ na životnu sredinu, uzorci uglja, pepela i šljake iz termoelektrana „Nikola Tesla“ i „Kolubara“ mereni su poluprovodničkim HPGe spektrometrom u Laboratoriji za nuklearnu i plazmu fiziku Instituta „Vinča“. Kao rezultat ovih merenja, dobijene su koncentracije prirodnih radionuklida i veštačkog radionuklida 137Cs kao, što je prikazano u ranije objavljenim radovima. Prikazani rezultati su u saglasnosti sa istraživanjima sprovedenim širom sveta. Da bi se obezbedila tačnost i preciznost (pouzdanost) dobijenih rezultata merenja, u okviru Laboratorije uspostavljen je program kontrole kvaliteta (QC) i osiguranja kvaliteta (QA). Interna kontrola obuhvata proveru karakteristika poluprovodničkog HPGe spektrometra koji se koristi za merenje svih analiziranih uzoraka. Tačkasti izvori 60Co i 137Cs se koriste kao kontrolni izvori za proveru položaja pika, ukupne površine ispod pika, FWHM (puna širina na polovini maksimuma pika), FWTM (puna širina na desetini maksimuma pika) i odnos FWHM/FWTM. Pored navedenih karakteristika, redovno se kontroliše i ukupni odbroj prirodnog fona. Svaka od navedenih karakteristika može ukazati na neku nepravilnost u radu detektorskog sistema. Cilj ovograda je da se prikažu kontrolne karte ispitivanih karakteristika poluprovodničkog HPGe spektrometra korišćenog za merenje uzoraka uglja, pepela i šljake. Dobijene kontrolne karte predstavljaju važan alat na osnovu kojeg se analizira dugoročna stabilnost spektrome, eir daughter products, as well as 40K. It is widely used in industry as well as in energy pro-duction. The problems associated with the production of energy from coal is the so-called “energy waste”, such as ash and slag, which are incombustible and unburnt residue from combustion of coal. If ash and slag are released into the environment an increase and/or redistribution of natural radio-nuclide content can occur. To determine the potential impact of “energy waste” on the environment, samples of coal, ash, and slag from thermal power plant "Nikola Tesla" and "Kolubara" were meas-ured with a semiconductor HPGe spectrometer. Results of activity concentration of natural radionu-clides and artificial 137Cs in coal, slag and ash are presented in few previously published papers and obtained values are in accordance with similar worldwide investigations. o ensure the accuracy and precision (reliability) ofthe obtained measurement results, quality control (QC) and quality assurance (QA) program were established. Internal control includes check-ing of the characteristics of HPGe spectrometer used for measurement of all analysed samples. Point sources of 60Co and 137Cs are used as control sources for checking following characteristics: peak positions, net peak area, FWHMs (Full Width at Half Maximum), FWTMs (Full Width at Tenth Max-imum) and FWHM/FWTM ratios. In addition to the mentioned characteristics, the counting of back-ground is also regularly controlled. Each of the mentioned characteristics may indicate some irreg-ularity in the operation of the detector system and thus could influence reliability of performed activ-ity concentration measurements.The paper presents the control charts of the examined characteristics of the HPGe spectrometer used for measurements of coal, ash and slag samples. The obtained control charts indicate the long-term stability of the spectrometer and hence confirm accuracy and precision of measurement results.

Fourteen samples of nine different species were collected in the region of Fruška gora, the suburban areas of Belgrade, and the vicinity of Vlasina Lake (Serbia) have been analyzed from the radiological point of view. Specific activities of radionuclides 210Pb, 137Cs, and 40K were measured using a semiconductor HPGe spectrometer system in these wild mushroom samples. The activity concentrations of all measured dried wild mushrooms are for 210Pb: between 2.05 Bq/kg and 9.74 Bq/kg; for 137Cs: between < 0.2 Bq/kg and 19.3 Bq/kg; for 40K between 704 Bq/kg and 2530 Bq/kg. The total individual annual effective doses due to ingestion of 210Pb, 137Cs, and 40K radionuclides within a 0.5 kg dry mass of the wild mushrooms is between 3.99 µSv and 10.81 µSv, and are much lower than the recommended level for the public (1 mSv/y).

Kontrola kvaliteta laboratorijskog procesa zauzima značajno mesto u svakodnevnom laboratorijskom radu. Obzirom na važnost, međunarodni standardi su propisali načine i zahteve za vršenje ovakve kontrole. Jedan od zahteva standarda ISO 17025 je obezbeđenje poverenja u rezultate merenja, koje se, između ostalog, može vršiti kontinuiranim praćenjem parametara karakterističnih za laboratorijsku metodu od interesa preko konstruisanja tzv. kontrolnih karti. U radu su prikazani rezultati troipogodišnje analize rada gamaspektrometrijskog sistema u Laboratoriji za nuklearnu i plazma fiziku INN „Vinča“. Merenja su vršena jednom nedeljno a kao kontrolni izvori korišćeni su tačkasti izvori Co-60 i Cs-137. Pored praćenja odbroja ispod pika, položaja pika, širine na polovini visine pika (FWHM), širine na desetini visine pika (FWTM), kao i njihovog međusobnog odnosa (FWTM/FWHM), praćen je i odbroj u fonu. Rezultati su pokazali da gamaspektrometrijski sistem ima zadovoljavajuću stabilnost u radu u dužem vremenskom periodu., Quality control of the laboratory process plays an important role in daily laboratory work. Due to its importance, international standards have issued the ways and requirements for performing such a task. One of the requirements of the ISO 17025 standard is to ensure confidence in the measurement results, which, among other things, can be done by continuously monitoring the parameters characteristic of the laboratory method of interest through the construction of the so-called control charts. The paper presents the results of a three-and-a-half-year analysis of the gamma spectrometric system measurements in the Laboratory for Nuclear and Plasma Physics of the INN "Vinča". Measurements were made once a week and point sources Co-60 and Cs-137 were used as control sources. In addition to monitoring the count below the peak, the position of the peak, the full width at half maximum (FWHM), the full width at tenth maximum (FWTM), as well as their mutual ratio (FWTM/FWHM), the count in the background was also monitored. The results show that the gamma spectrometric system has satisfactory stability over a long period of time.

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.

Knjiga jedne od trenutno najpoznatijih žena fizičara, Sabine Hosenfelder, Lost in Math: How Beauty Leads Physics Astray, predstavlja povod za raspravu o krizi u koju je zapala moderna fizika, ali i novim tendencijama u fizici kao mogućim načinima da se nastalo stanje prevaziđe. Jedan deo odgovornosti za višedecenijsku stagnaciju u razvoju fizike snose određeni aspekti nasleđa antičke, konkretno pitagorejsko- platonske filozofije, koji su pronašli svoje mesto u modernoj nauci. Kritički uvidi koje iznosi Hosenfelderova veoma su dobro utemeljeni. Ipak, autorki se može zameriti da previđa neke pravce mišljenja u fizici koji predstavljaju snažnu alternativu estetskim teorijskim pristupima, uglavnom inspirisanim starogrčkom filozofijom prirode. Na primer, knjiga fizičara Fritjofa Kapre Tao fizike, ukazuje na mnogobrojne paralele između istočnjačkih sistema mišljenja i fizike 20. veka., The book of one of the currently most famous female physicists, Sabine Hossenfelder, Lost in Math: How Beauty Leads Physics Astray, is a reason for discussing the crisis in which modern physics has fallen, as well as new tendencies in physics as possible ways to overcome the situation. Part of the responsibility for decades of stagnation in the development of physics is borne by certain aspects of the heritage of ancient, specifically Pythagorean-Platonic philosophy, which have found their place in modern science. The critical insights presented by Hossenfelder are very well founded. However, the author can be criticized for overlooking some ways of thought in physics that represent a strong alternative to aesthetic theoretical approaches, mostly inspired by ancient Greek natural philosophy. For example, physicist Fritjof Capra’s book The Tao of Physics points to numerous parallels between Eastern systems of thought and 20th century physics.

The purpose of this work is to assess accuracy and compare the performance of radionuclide calibrators (RNCs) used in nuclear medicine departments in Serbia. Testing of the RNCs included verification of measurement accuracy, as well as analysis of routinely used quality control protocols, by using the certified radioactivity standards (57Co, 137Cs). RNCs performances were assessed with 99mTc through comparison of reference value for radionuclide activity and RNC measurements. Results of the intercomparison revealed that RNCs, 15 in total, are accurate within 10% in vial geometry and within 15% in syringe geometry. Most of them showed similar performance. The results revealed that container geometry is an important influencing parameter in the accuracy of activity measurement. Obtained results indicate a need for regular calibration and implementation of Quality Control program in order to achieve and maintain the accuracy of activity measurements in nuclear medicine.

Gotovo svaki istraživač antičke filozofije bavio se pitagorejcima i pitagorejskom filozofijom, pa tako i Ksenija Atanasijević u svojim spisima razmatra neke od najpoznatijih navoda o Pitagori i njegovom učenju. Ovom prilikom, podsetićemo se osnovnih načela pitagorejske tradicije, kao što je, recimo, shvatanje da se struktura sveta može izraziti putem harmoničnih, celobrojnih odnosa fizičkih veličina, što je inače podstaknuto muzičkom analogijom. Za upućene pitagorejce (mathematikoi), upravo je neprekidna dinamika simetrije i asimetrije ono što konstituiše razliku između reda, poretka (kosmos) i nereda (haos). Iako je sa stanovišta modernih prirodnih nauka ovakav pojednostavljen, gotovo estetski pristup proučavanju prirode uglavnom prevaziđen, značajno je primetiti da on u jednom drugačijem, osavremenjenom obliku opstaje u nekim od vodećih naučnih teorija. Takođe, biće reči i o pitagorejskom učenju o metempsihozi (metempsychosis), tj. „selenju duša“, koje usvaja i Platon u nekolicini svojih dijaloga. Svakako, Ksenija Atanasijević posvećuje pažnju pitagorejskoj praksi da se filozofsko obrazovanje omogući i nadarenim ženama. Premda se antički feminizam po mnogo čemu razlikuje od savremenog, može se reći da su pitagorejci načinili prve ozbiljnije korake u pravcu ženske emancipacije., Almost every researcher of ancient Greek philosophy dealt with the Pythagoreans and Pythagorean philosophy. In her writings, Ksenija Atanasijević discusses some of the most famous allegations about Pythagoras and his teachings. On this occasion, we will recall the basic principles of the Pythagorean tradition, such as, for example, the understanding that the structure of the world can be expressed through harmonious,whole-number ratios of physical quantities, which is inspired by musical analogy. For the learned Pythagoreans (mathematikoi), it is precisely the continuous dynamics of symmetry and asymmetry that constitutes the difference between order (kosmos) and chaos (haos). Although from the point of view of modern natural sciences this simplified, almost aesthetic approach to the study of nature is mostly outdated, it is important to note that it survives in a different, modernized form within some of the leading scientific theories. Also, we will discuss the Pythagorean doctrine of metempsychosis, ie. “transmigration of souls”, which is adopted by Plato in several of his dialogues. Certainly, Ksenija Atanasijević pays attention to the Pythagorean practice of providing philosophical education to gifted women. Although ancient feminism differs in many ways from modern feminism, it can be said that the Pythagoreans took the first serious steps in the direction of Women’s emancipation.

This study showed that 137Cs concentrations in black walnut leaf and fruit, as well as in tinctures were below the detection limits. Concentrations of other radionuclides are lower than their concentrations in the soil, except for concentration of 40K in black walnut fruit, which objectively have more potassium due to the structure of the fruit. It indicates that the consumption of leaf and nut tinctureis absolutely safe, especially in relation to artificial radionuclides.

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.

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.

Aleksandar Kandić (Jeremy Bell and Michael Nass (eds.), Plato’s Animals, Indiana University Press, Bloomington, 2015)

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.

U Platonovoj filozofiji, matematički entiteti i pojmovi zauzimaju centralnu ulogu u nekim epistemološkim, kosmološkim, pa i estetičkim razmatranjima. Platon se, medjutim, ne služi matematičkim pojmovima na formalan način, već nastoji da ispita poreklo našeg saznanja matematičkih entiteta, te njihov ontološki status. U ovom radu, sledeći uticajne interpretatore antičke filozofije, autor nastoji da rekonstruiše Platonovu argumentaciju u kosmološkom dijalogu Timaj na osnovu koje se može zaključiti nesto o više o Platonovom shvatanju porekla i prirode matematičkih entiteta koji su, prema mišljenju atinskog filozofa, psihofizičkog karaktera., In Plato’s philosophy, mathematical entities and concepts play a central role in some epistemological, cosmological, and even aesthetic considerations. Plato, however, does not use mathematical concepts in a formal way, but seeks to examine the origin of our knowledge of mathematical entities, as well as their ontological status. In this paper, following influential interpreters of ancient philosophy, author seeks to reconstruct Plato’s argument in the cosmological dialogue Timaeus, in order to reveal more about Plato’s understanding of the origin and nature of mathematical entities, which are, according to the Athenian philosopher, psychophysical in character.

Gamma ray spectrometry with high purity germanium (HPGe) detector is one of the most widely used methods for environmental samples measurements. It is basically a non-destructive method and usually there is no need for the extensive sample preparation. True coincidence summing effect has a significant effect in gamma ray spectrometry analysis, especially in low source-to-detector geometry. Many authors have paid attention to this problem mainly by analyzing and determining coincidence summing correction factors for artificial radionuclides. However, the effect of true coincidence summing can significantly affect the result obtained by gamma ray spectrometry of environmental samples. Therefore, special attention should be paid to the determination of correction factors for coincidence summing of radionuclides from natural series (uranium, thorium and actinium series). Coincidence summing correction factors can be determined in several manners. Application of appropriate software packages is one of the most common. Software packages EFFTRAN and GESPECOR are among the most used ones. These software are based on Monte Carlo simulation. EFFTRAN is efficiency transfer code with semiempirical approach, whereas GESPECOR is dedicated code specifically tailored to solve most of the problems concerning gamma spectrometric measurements. The values of the correction factors depend on the detector geometry as well as the relevant data related to analyzed sample. The geometry of the detector implies the parameters of the detector itself (crystal dimensions, thickness of the dead layer, the thickness of the detector window). On the other hand, the relevant data related to analyzed sample includes dimensions of the container in which the sample is packed, sample density, chemical composition. The aim of this work is to compare coincidence summing factors obtained by using EFFTRAN and GESPEOR software in the case of p-type semiconductor HPGe detector with 30 % relative efficiency. Al

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.

Specific activity of 137Cs, 40K, and 210Pb radionuclides in fifteen selected medicinal herbs from three locations in Central Serbia (two mountains, Kopaonik and Zlatar, and a valley, Sokobanja) was measured using two semiconductor HPGe spectrometer systems. The obtained values are in intervals (<0.3 ÷ 9.7) Bq/kg, (<0.2 ÷ 24.7) Bq/kg, and (<0.2 ÷ 5.7) Bq/kg for 137Cs; in intervals (125 ÷ 1100) Bq/kg, (104 ÷ 872) Bq/kg, and (103 ÷ 954) Bq/kg for 40K, and in intervals (3.6 ÷ 49.0) Bq/kg, (3.9 ÷ 57.9) Bq/kg, and (2.8 ÷ 103) Bq/kg for 210Pb, for herbs from Kopaonik, Sokobanja and Zlatar, respectively. The highest activity measured in individual herbs was: 24.7 Bq/kg for 137Cs (Sokobanja valley), 1100 Bq/kg for 40K (Mt. Kopaonik) and 103 Bq/kg for 210Pb (Mt. Zlatar). The corresponding individual annual effective doses due to ingestion calculated from the measured activity concentrations, of the radionuclides are: in intervals (<1.7 ÷ 82.9) nSv, (<1.4 ÷ 211) nSv, and (<1.1 ÷ 48.7) nSv for 137Cs; in intervals (0.76 ÷ 4.5) μSv, (0.64 ÷ 4.4) μSv, and (0.63 ÷ 4.9) μSv for 40K, and in intervals (1.1 ÷ 18.2) μSv, (1.3 ÷ 21.6) μSv, (0.9 ÷ 38.3) μSv for 210Pb, respectively. The specific activity concentration values of 137Cs and 40K obtained for the investigated herbs are similar to the literature data, while no information was found in literature about specific activity concentration of 210Pb. The all values obtained for individual annual effective dose due to ingestion are less than 100 μSv, which means that the daily use of 200 mL of herbal infusion during a year made from the investigated herbs does not represent a radiological risk for health. However, a high individual annual effective dose of ingestion of 210Pb obtained for some herbs indicate that their consumption in larger amounts 2–3 cups of infusion daily over a year could make the dose to exceed the recommended level, and points to necessity for extensive investigation of 210Pb activity concentration worldwide. © 2019

The probabilities of locating peaks with a high relative peak-area uncertainty were determined empirically with nine types of peak-location software used in laboratories engaged in gamma-ray spectrometry measurements. It was found that it is not possible to locate peaks with a probability of 0.95, when they have a relative peak-area uncertainty in excess of 50%. Locating peaks at these relatively high peak-area uncertainties with a probability greater than 0.95 is only possible in the library-driven mode, where the peak positions are supposed a-priori. The deficiencies of the library-driven mode and the possibilities to improve the probabilities of locating peaks are briefly discussed. © 2019 Elsevier Ltd

This paper presents the results of analyses of radionuclide content in the samples of the surrounding soil and clayey material of “Zbegovi” open-pit mine in Donje Crniljevo, Serbia. Samples from 78 sites were collected and prepared. The activity concentrations were determined for radionuclides: 238U, 232Th, 40K, 226Ra, and 137Cs. The mean values obtained are as follows: 23 Bqkg–1, 89 Bqkg–1, 372 Bqkg–1, 56 Bqkg–1, and 11 Bqkg–1, respectively. Concentrations of 238U, 40K, and 226Ra in the studied area do not deviate from the values obtained for the soil in Serbia. The concentration of 232Th in the studied area is slightly higher relative to average values for soil, and slightly lower compared to similar deposits of clayey material in the world. Measurements performed showed that the open-pit mine of clayey material is completely uncontaminated surface as far as 137Cs is concerned, while there are sites where measured 137Cs concentrations are significantly higher, which is due to topographic differences and inhomogeneous surface contamination of land after the Chernobyl accident. To assess the radiological risks in the observed area, the following indices were determined: absorbed dose rate, annual outdoor effective dose, absorbed dose for biota, excess lifetime cancer risk outdoors as well as external radiation hazard index. The mean value of the estimated absorbed dose rate in the given area amounts to 80.1 nGyh–1, and the annual outdoor effective dose ranges from 46.9 to 134 Sv. Absorbed dose rate for biota in the studied area is 1.31 10–4 Gyd–1. The mean excess lifetime cancer risk outdoors for the population is 3.8 10–4, and t he mean value of the external radiation hazard index obtained in this study is 0.48, which is consistent with the world average. A low dose of radiation will not pose a risk to the population and biota in the studied area.

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.

Lekovite biljke imaju dugu istoriju upotrebe širom sveta u tradicionalnoj medicini. MeĎutim, njihova upotreba, kao i upotreba biljnih proizvoda mora se kontrolisati,kako bi se izbegla pojava neţeljenih efekata na zdravlje ljudi. Specifične aktivnosti radionuklida 40K, 137Cs i 210Pb u uzorcima lekovitih biljaka izmerenesu pomoću poluprovodničkog HPGe spektrometarskog sistema, na osnovu čega je odreĎena prosečna godišnja efektivna doza ingestije za odrasle koji piju dnevno 200 ml čaja pripremljenog od lekovitih biljaka. U radu je prikazana radiološka analiza 7 odabranih lekovitih biljaka sa područja Majdanpeka. Dobijene vrednosti za efektivnu dozu ingestije slične su vrednostima objavljenim u drugim studijama i manje su od 100 μSv, što upućuje na zaključak da svakodnevna upotreba čajeva od analiziranih lekovitih biljaka sa područja Majdanpeka ne predstavlja značajan radiološki rizik po zdravlje., Medicinal plants have a long history in traditional medicine worldwide. However, their use, as well as the use of plant products, must be controlled in order to avoid the occurrence of undesirable effects on human health. Specific activities of radionuclides 40K, 137Cs and 210Pb in samples of medicinal plants were measured using a semi-conductor HPGe spectrometer system. The average annual effective dose for adults due to daily ingestion of 200 ml herbal infusion prepared from medicinal plants is determined. In this paper a radiological analysis of 7 selected medicinal plants from the area of Majdanpekis presented. The values obtained for an effective dose of ingestion are similar to the values published in other studies and are less than 100 μSv, suggesting that the daily use of herbal infusions from analyzed medicinal plants from the Majdanpek area does not represent a significant radiological health risk

Između Platonovog pojma nauke (episteme) i modernog pojma nauke postoje gotovo nepremostive razlike, ali i određene sličnosti. U poznim dijalozima kao što su Teetet, Fileb, ili Timaj, Platon u izvesnoj meri redefiniše sopstveni pojam znanja koji je razvio u Državi. Pravo znanje se ne mora odnositi isključivo na nepromenljive aspekte stvarnosti. Platonova karakterizacija kosmologije kao eikos logos-a ("verovatne" priče, eng. likely story) u dijalogu Timaj predstavlja jedan vid anticipacije koncepta opovrgljivosti, koji dominira modernom filozofijom nauke. Iskustvo i osmatranje, te matematički, psihološki i biološki pojmovi, zauzimaju značajno, neizostavno mesto u strukturi Timajevog kosmološkog modela., There are almost irreconcilable differences between Plato's notion of science (episteme) and the modern notion, but also certain similarities. In the late dialogues such as The Theaetetus, The Philebus, and The Timaeus, Plato redefines his own notion of knowledge developed in The Republic to some extent. Genuine knowledge does not refer solely to the unchangeable aspects of reality. Plato's characterization of cosmology as an eikos logos ("likely story") in The Timaeus is an anticipation of the concept of falsifiabilit that dominates modern philosophy of science. Experience and observation, as well as mathematical, psychological and biological concepts, occupy a significant, indispensable place within the structure of Timaeus' cosmological model.

The coincidence summing effect plays an important role in HPGe spectrometry, especially at low source-detector distances, due to a large solid angle; therefore, the calculation of correction factors is necessary. The aim of the research described in this paper was to compare values of correction factors for a 22Na point source obtained using the GESPECOR software package (Monte-Carlo method) and experimentally obtained values. Measurements were performed using a semiconductor HPGe spectrometer and the point source axially positioned at nine different distances from the detector end-cap. For the purpose of determining correction factors, a system of equations was formed, which, besides nuclear data as the input parameters, uses the experimentally obtained values of the total count in the entire spectrum, as well as the counts in the full energy peaks. The system of equations was solved for each particular case and correction factors were determined. By comparing the results obtained using the experimental and Monte-Carlo method, it was found that the correction factors for the 22Na point source have discrepancies less than 3%. The significance of these discrepancies was also verified from a statistical point of view using a Student's t-test. © 2019 RAD Association. 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.