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The crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined experimentally and theoretically.

Jedan od značajnih načina kontrole rada termoelektrana (TE) na ugalj je kontinuirano praćenje vrednosti koncentracija aktivnosti radionuklida prirodnog porekla sadržanih prvenstveno u uglju, a potom i uzorcima pepela i šljake kao glavnim produkatima sagorevanja uglja koje je zbog svoje obilne proizvodnje neophodno odlagati na deponije otpada. Koncentracije aktivnosti prirodnih radionuklida 238U, 235U, 226Ra, 210Pb, 232Th i 40K, koje bi u životnoj sredini potencijalno mogle biti preraspodeljene kao posledica rada TE, podležu redovnoj kontroli u uzorcima uglja, šljake, elektrofilterskog pepela, kao i u uzorcima sakupljenim sa deponija pepela, na aktivnoj i pasivnoj kaseti, i zemljištu uzorkovanom na manjoj i većoj udaljenosti od TE. Predmet ovoga rada je analiza rezultata višegodišnjih merenja obavljenih u periodu od 2010. do 2022. godine. Godišnje vrednosti koncentracija aktivnosti izmerene za svaki ispitivani radionuklid i svaku od sedam vrsta uzoraka posmatrane su kao hronološki nizovi podataka koji čine diskretne vremenske serije za koje su rezultati statističke analize ukazivali da se mogu opisati kao procesi tzv. belog šuma., One of the most important means of controlling the operation of coal-fired power plant (CFPP) is the continuous monitoring of naturally occurring activity concentrations of radionuclides contained primarily in coal and, consequently, in ash and slag samples, the main coal combustion products that must be disposed of in landfills due to their high production. The activity concentrations of the naturally occurring radionuclides 238U, 235U, 226Ra, 210Pb, 232Th, and 40K, which could potentially be released into the environment as a result of the CFPP operation, are regularly monitored in the samples of coal, slag, and fly ash, as well as in the samples of ash piles on the active and passive cassettes and in the soil sampled at lesser and greater distances from the CFPP. The aim of this work is to analyse the results of the multi-year activity concentration measurements carried out in the period from 2010 to 2022. The annual activity concentration values measured for each studied radionuclide and each of the seven sample types were observed as a chronological sequence of data forming discrete time series, which, according to the results of statistical analysis, may be described as white noise processes.

MetroPOEM (Metrology for harmonization of measuremenets of environmental pollutant in Europe) je trogodišnji evropski projekat finansiran u okviru EMPIR programa.Globalna težnja ka što manjem zagadjenju (European Green Deal´s ambition for zero pollution) zahteva razvoj visoko osetljivih tehnika kojima se mogu detektovati niske koncentracije polutanata. Masena spekrometrija je najznačajnija tehnika za odredjivanje neradioaktivnih, ali i dugoživućih radioaktivnih polutanata. Glavni cilj ovog projekta je da uspostavi vezu izmedju radiometrijskih i masenih tehnika merenja polutanata. Takođe, cilj projekta je i smanjenje mernih nesigurnosti, limita detekcije, ali i razvoj novih referentnih materijala kojima bi se obezbedila sledivost mernih procedura., The MetroPOEM project (Metrology for harmonization of measurements of environmental pollutants in Europe) is a three-year European project financed under the EMPIR program. The global aspiration towards as little pollution as possible (European Green Deal's ambition for zero pollution) requires the development of highly sensitive techniques that can detect low concentrations of pollutants. Mass spectrometry is the most important technique for determining non-radioactive, but also long-lived radioactive pollutants. The main goal of this project is to establish a link between radiometric and mass pollutant measurement techniques. Also, the goal of the project is the reduction of measurement uncertainties, detection limits, but also the development of new reference materials that would ensure the traceability of measurement procedures.

In this work, the thermal decomposition process of coal bottom ash (collected after lignite combustion in coal-fired power plant “Kostolac B” (TEKO-B), Serbia) was investigated, using simultaneous TG (thermogravimetry) – DTG (derivative thermogravimetry) techniques in an inert (Ar) atmosphere, at various heating rates (10.3, 20.9 and 32.1 K/min). In addition to thermal characterization of the sample, the chemical composition and naturally occurred radionuclides were also determined. Using the model-free (isoconversional) (by Friedman (FR), Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW) and Vyazovkin (VY) methods) analysis, the complex kinetic nature of the process was successfully resolved. The conducted numerical optimization of the process (using non-linear least square optimization) had confirmed accuracy and reliability of estimated kinetic parameters. Model-based (model-fitting) kinetic analysis showed the existence of a complex reaction scheme, over two consecutive reactions steps and one single-stage reaction step, via mechanism order An, F2, Fn, R3, Cnm (through n-dimensional nucleation/growth, chemical reactions, and n-th order and m-power with autocatalysis mechanisms). Through physicochemical interpretation of mechanism scheme, an assessment of recovery of valuable metals and metal oxides was performed, by analysing the concentration of reaction species in a function of temperature of individual steps. Likewise, the influence of certain precursor involved in decomposition process as catalyst (in order to increase the yield of targeted product) was also inspected. Finally, the simulation of actual process using the results obtained from applied methods/models was performed, through application of modulated dynamic (MD) prediction.

The crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined experimentally and theoretically.

Determination of specific activity concentration of radioisotopes in environmental samples can be used to assess the long-term kinetics of the decline of radioisotopes. Based on the obtained activity concentrations of tritium in the Danube, the effective ecological half-life is estimated. Assuming that the Danube in Belgrade is not affected by nuclear power plants, even though it is positioned downstream of the Paks Nuclear Power Plant in Hungary, a slow decline of tritium was observed. The effective ecological half-life of tritium was also determined after correction by subtracting its components originating from cosmic radiation and the atmospheric transfer from nuclear facilities worldwide.

This paper presents the results for gross alpha and gross beta activity in leaves samples: Fig (Ficus carica), Vine (Vitis vinifera L.), and Apricot (Prunus armeniaca). Samples were collected in Iraq (Sulaymaniyah, Kurdistan region), and in the Serbia (Belgrade), in the summer 2018. The analysis was done in dried and milled samples as well as in the annealed samples, using gas flow proportional counter. Determination of gross alpha and gross beta activity presents rapid method, essential for the analysis of radioactivity in environmental samples. The gross alpha activity is defines as the total activity of alpha emitters, and originates from the decay chains of 238U and 232Th, which quantity depends on the geological and geographical formation of natural radionuclides. The main contributor to the gross beta activity is natural long-lived isotope 40K, as well as 210Pb, 228Ra. The gross beta measurements also include a contribution from anthropogenic radionuclides 137Cs and 90Sr. Radionuclides that emitting low-energy beta radiation (3 H and gaseous or volatile radionuclide such as iodine) cannot be detected by gross beta activity measurements.

This paper presents distribution and seasonal variations of tritium, radioactive isotope of hydrogen, in Sava River in Belgrade. Tritium besides its natural origin also has an artificial origin, through human activity including the operation of nuclear power plants, nuclear weapons manufacturing and atomic bomb tests. Knowing the concentration of tritium in the Sava River in Belgrade is important because it is located downstream from the Krško Nuclear Power Plant in Slovenia. Analysis of tritium concentrations in surface water samples were done in composite monthly samples during 2017-2022. Tritium activity was determined by liquid scintillation spectrometer using electrolytic enrichment. Seasonal variations were estimated by determination of average monthly concentrations and seasonal indices.

Measurement of radon (222Rn) concentration using charcoal filters according to the EPA 520/5-87-005 method is performed in Radiation and Environment Protection Department of Vinča Institute for Nuclear Sciences on NaI scintillation detectors. Concentration of radon adsorbed on active charcoal is determined indirectly, by gamma spectrometry of its daughter products via their gamma peaks at 295 keV, 352 keV (214Pb) and 609 keV (214Bi). In order to assure the reliability of the measurement results, and in accordance with Standard ISO 17025/17 quality control and quality assurance (QA/QC) procedures needs to be applied. Related activities ought to be planned, described in the quality control documentation, performed in a systematic manner, recorded and reviewed. First, the energy and efficiency calibration of the detection system needs to be performed in a proper manner. The NaI scintillation spectrometer is internally calibrated using the certified radioactive 226Ra standard in charcoal matrix and in the geometry identical to the measurement geometry, produced by Czech Metrology Institute and traceable to Bureau International des Poids et Mesures (BIPM). As defined in laboratory’s procedures a regular quality control of the NaI scintillation detector is performed once a week. Quality control activities include the background measurement and measurement of adequate reference material. Gross background count rate in the energy region of interest is used to verify that the detector and shield have not been contaminated and that there is no significant variation of the background. Reference material used is the soil sample with known content of 226Ra. Gross count rate in the reference material spectrum is used to check the energy and efficiency calibration. These values are recorded and verified if they are within the acceptance limits. Obtained results, together with acceptance limits, for a certain period (one year usually) is graphically presented in the control charts.

As a part of regular activities of the accredited laboratory, the Laboratory for Radiation Measurements of the Radiation and Environmental Protection Department, Institute Vinča, every year takes part in the proficiency tests organized by IAEA. This year, within the framework of IAEA – TERC – 2022 – 01/02 Proficiency Test, one of the requests was to measure the simulated surface contamination using the instrument that are at the disposal in the participant laboratories. The results should be reported in the units of counts/s/cm2 in order to be comparable. In this paper, the measurement method and subsequent specific calculations for the simulated surface contamination are explained and the results of the proficiency test stated and discussed.

U radu je prikazana procena stanja u životnoj sredini Mokre Gore, posmatrano sa radioekološkog aspekta. Rezultati gamaspektrometrijskih merenja sprovedenih na germanijumskom detektoru visoke čistoće su pokazala prisustvo 226Ra, 232Th i 40K u zemljištu Mokre Gore u koncentracijama aktivnosti: od 10 Bq/kg do 20 Bq/kg za 226Ra, 13 Bq/kg do 34 Bq/kg za 232Th i 96 Bq/kg do 250 Bq/kg za 40K. Na osnovu rezultata gamaspektrometrijskog merenja aktivnosti navedenih primordijalnih radionuklida, izvršena je procena radijacionog rizika usled terestričkog izlaganja stanovništva na području Mokre Gore. Proračunom su procenjeni sledeći parametri radijacionog rizika: ukupna jačina doze gama zračenja (srednja vrednost 28,6 nGy/h), godišnja efektivna doza (srednja vrednost 0,035 mSv) i indeks radijacionog rizika usled spoljašnjeg izlaganja (srednja vrednost 0,169). Procenjene vrednosti navedenih parametara ukazuju na to da ne postoji uvećan radijacioni rizik za stanovništvo ispitanog područja usled terestričkog izlaganja.

Gasni proporcionalni brojač koristi se za određivanje ukupne alfa i ukupne beta aktivnosti u različitim matriksima kao i za određivanje aktivnosti antropogenog radionuklida 90Sr koji je čist beta emiter. Ovaj rad predstavlja pregled kontrole kvaliteta gasnog proporcionalnog brojača Thermo-Eberline FHT 770T i određivanja efikasnosti, koja se sprovodi sa sertifikovanim standardima 241Am i 90Sr. Brojač ima mogućnost simultanog merenja na 6 detektora i određivanja aktivnosti reda mBq. U radu su prikazani i rezultati sprovedene eksterne kontrole kvaliteta učešćem u interkomparativnom merenju 90Sr, ukupne alfa i ukupne beta aktivnosti u uzorcima vode, organizovanom od strane Međunarodne Agencije za Atomsku Energiju tokom 2022. godine.

Mjerenja koncentracije aktivnosti radionuklida Be-7 (berilij-7), Pb-210 (olovo 210) i Cs-137 (cezij-137) u Zemljinoj atmosferi neophodna su za razumijevanje atmosferskih procesa, kvalitete zraka i radioaktivnosti okoliša. Berilij-7 je radioaktivni izotop koji prvenstveno nastaje interakcijom kozmičkih zraka s atomima dušika i kisika u gornjoj atmosferi. Njegov kratki poluživot čini ga vrijednim tragačem za atmosferske procese u relativno kratkim vremenskim razdobljima. Olovo-210 je radioaktivni izotop čiji je primarni izvor u atmosferi raspad plina radona. S dužim poluživotom od Be-7, pogodan je za proučavanje dugotrajnijih atmosferskih procesa. Cezij-137 je, s druge strane, antropogeni radioizotop s vremenom poluraspada čak i dužim od onog Pb-210, što ga čini dobrim dugoročnim ekološkim tragačem. Nedavno je uspostavljena baza podataka za praćenje radioaktivnosti tla u zraku (GRAMON). Sadrži rezultate mjerenja radioaktivnosti u površinskom zraku na sedam lokacija: Beograd (Srbija), Ljubljana i Krško (Slovenija), Sarajevo (Bosna i Hercegovina), Podgorica (Crna Gora), Skopje i Bitola (Sjeverna Makedonija). Naš rad daje statističku analizu mjesečnih (prosječnih) vrijednosti koncentracija aktivnosti radionuklida za svaku lokaciju od 2010. do 2019. Rezultati pokazuju prostorne razlike i vremensku evoluciju radioaktivnosti zraka u ovoj regiji koja je obično nedovoljno zastupljena u velikim studijama., Measurements of activity concentrations of radionuclides Be-7 (beryllium-7), Pb210 (lead210), and Cs-137 (cesium-137) in the Earth’s atmosphere are essential for understanding atmospheric processes, air quality, and environmental radioactivity. Beryllium-7 is a radioactive isotope produced primarily by cosmic ray interactions with nitrogen and oxygen atoms in the upper atmosphere. Its short half-life makes it a valuable tracer for atmospheric processes on relatively short timescales. Lead210 is a radioactive isotope whose primary source in the atmosphere is decay of radon gas. With a longer half-life than Be-7, it is suitable for studying longerterm atmospheric processes. Cesium-137, on the other hand, is an anthropogenic radioisotope with a half-life even longer than that of Pb-210, which makes it a good long-term environmental tracer. The Ground Air Radioactivity Monitoring (GRAMON) database has been recently established. It contains the outcomes of radioactivity measurements in the surface air at seven locations: Belgrade (Serbia), Ljubljana and Krško (Slovenia), Sarajevo (Bosnia and Herzegovina), Podgorica (Montenegro), Skopje and Bitola (North Macedonia). Our paper gives a statistical analysis of monthly (average) values of the radionuclides’ activity concentrations for each location from 2010 to 2019. The results demonstrate spatial differences and temporal evolution of air radioactivity over this region commonly underrepresented in large-scale studies.

U ovom istraživanju analizirana je fraktalna priroda vremenske serije specifične aktivnosti berilijuma-7 u površinskom sloju atmosfere u Beogradu, Srbija, sa ciljem da se prouči dinamika njene samosličnosti, a s posebnim fokusom na godišnji ciklus. Korišćene su metode vejvlet analize i vremenski zavisne detrendovane pokretne srednje vrednosti radi identifikacije karakterističnih intervala i procene Hurstovih eksponenata. Podaci o specifičnoj aktivnosti berilijuma-7 preuzeti su iz GRAMON baze podataka, za lokaciju Beograd (44,88 °N; 20,58 °E; 95 m nadmorske visine). Vremenska serija obuhvata 362 mesečna merenja od 1991. do 2022. godine. Rezultati ukazuju na postojanje izraženog godišnjeg ciklusa u ovoj vremenskoj seriji. Takođe, promene u lokalnom Hurstovom eksponentu otkrivaju varijacije u ponašanju vremenske serije – ona iz umereno korelisanog prelazi u izrazito antikorelisan proces između 2015. i 2020. godine. Ovaj rezultat biće predmet šire analize koja uključuje i druge lokacije iz GRAMON baze podataka.

U radu je razmatran potencijalni odnos između dobijenih rezultata za koncentraciju tricijuma u kišnici i rekama, Savi i Dunavu, u Beogradu. Uzorkovanja su vršena svakog meseca tokom 2021. godine. Svi uzorci su koncentrisani primenom metode sa elektrolitičkim obogaćenjem, dok je za detekciju tricijuma korišćen tečni scintilacioni spektrometar. Dobijeni rezultati korišćeni su za izračunavanje količine tricijuma deponovane po m2 površine, kao i prosečnog toka tricijuma u rekama na osnovu protoka vode. Dobijena distribucija tricijuma tumačena je u skladu sa meteorološkim i hidrološkim parametrima., The potential relationship between the obtained results for the tritium concentration in precipitation and in the Sava and Danube River in Belgrade was analyzed. Sampling was done during 2021. All samples were concentrated using the method with electrolytic enrichment, while a liquid scintillation spectrometer was used for tritium detection. The obtained results were used to calculate the amount of tritium deposited per m2 of surface as well as to estimate the average flow of tritium in rivers based on river water flow. The obtained distribution of tritium was interpreted in accordance with meteorological and hydrological parameters.

Sprovedeno istraživanje je usmereno na analizu trenda promene ukupne alfa i ukupne beta aktivnosti u poljoprivrednom zemljištu i usevima višegodišnjeg oglednog polja. Analiza je urađena primenom akreditovane metode za određivanje ukupne alfa i ukupne beta aktivnosti u čvrstim matriksima. Merenja su obavljena u Laboratoriji za zaštitu od zračenja i zaštitu životne sredine Instituta za nuklearne nauke “Vinča” na niskofonskom gasnom proporcionalnom brojaču Thermo Eberline FHT 770T. Izmerene vrednosti ukupne alfa aktivnosti variraju od 158 Bq/kg do 324 Bq/kg i ukupne beta aktivnosti od 600 Bq/kg do 1324 Bq/kg za uzorke zemljišta. Za uzorke biljnih kultura vrednosti ukupne alfa aktivnosti su u intervalu od 5 Bq/kg do 167 Bq/kg suve materije, dok su vrednosti ukupne beta aktivnosti u intervalu od 180 Bq/kg do 584 Bq/kg suve materije. Rezultati istraživanja su značajni, jer daju osnovne radiološke informacije od vitalnog značaja za ispitivano područje. Ovo je prvi pokušaj generisanja osnovnih podataka o radijacionom opterećenju zemljišta i biljnih kultura poljoprivrednog ekosistema alfa i beta emiterima, koji su određeni skrining metodom za monitoring životnog okruženja., The conducted research is focused on the analysis of the trend of changes in gross alpha and gross beta activity in agricultural soil and crops of perennial experimental fields. The analysis was performed using an accredited method for determining gross alpha and gross beta activity in solid matrix. The measurements were performed in the Radiation and Environmental Protection Department in Vinča Institute of nuclear Sciences on a low-level gas proportional counter Thermo Eberline FHT 770T. The measured values of gross alpha activity varied from 158 Bq/kg to 324 Bq/kg, and from 600 Bq/kg to 1324 Bq/kg for the gross beta activity in soil samples. For plant samples, values ranged from 5 Bq/kg to 167 Bq/kg of dry matter, and from 180 Bq/kg to 584 Bq/kg of dry matter for gross alpha and gross beta activity, respectively. The results of the research are significant, because they provide basic radiological information of vital importance for the investigated area. This is the first attempt to generate data base on the radiation load of soil and crops of the agricultural ecosystem with alpha and beta emitters, which were determined by the screening method for environmental monitoring.

Oko pola efektivne doze koju stanovništvo primi usled izlaganja jonizujućem zračenju potiče od radona i njegovih potomaka, te je problematika radona važna u oblasti zaštite od zračenja. Takođe, kao hemijski inertan gas, radon je našao primenu u izučavanju životne sredine kao traser za razne geološke i atmosferske procese. Jedna od važnih primena radona je u problematici praćenja gasova koji izazivaju efekat staklene bašte (greenhouse gases – GHG). Pokazano je da se poznavanjem fluksa radona iz zemlje i priraštaja koncentracije radona i koncentracije GHG u istom vremenskom intervalu tokom noći može odrediti fluks GHG. U ovom radu će biti prikazani odabrani rezultati nedavno završenog traceRadon projekta čiji je cilj bio razvijanje metrološki sledivih metoda merenja niskih koncentracija radona u atmosferi u granicama od 1 Bq m-3 do 100 Bq m-3, kao i unapređenje tehnika merenja i samo merenje radonskog fluksa, što će doprineti ispitivanju klimatskih promena kroz obezbeđivanje pouzdane procene fluksa GHG. Takođe, u sklopu projekta, vršila se procena do koje mere se radon u spoljašnjoj sredini i radonski fluks mogu koristiti za procenu radonskih prioritetnih oblasti., Since more than a half of the effective doses from all ionising radiation come from the exposure to radon and its progeny, radon is important in the field of radiation protection. Being a noble gas and therefore chemically inert, radon is also used as a tracer for different geological and atmospheric processes. Radon is of interest to climate scientists for monitoring greenhouse gasses (GHG). It is known that by knowing radon flux and variation of radon and GHG concentration at the same period of time during the night, it is possible to estimate emission of GHG. In this paper, the most important results of recently finished EMPIR project 19ENV01 traceRadon “Radon metrology for use in climate change observation and radiation protection at the environmental level” are presented. Project aimed to develop the capability to measure SI traceable radon activity in the range of 1 Bq m-3 to 100 Bq m-3, suitable for outdoor radon measurements, to develop the capability for traceable radon flux measurements in the field which is important for GHG emission estimates and validation of contemporary radon flux models. Within the project it was investigated to what extent radon flux and outdoor radon data could be used for estimation of radon priority areas.

Rutinska merenja uzoraka iz životne sredine gama spektrometrijom zahtevaju pripremu radioaktivnih standarda različitih matriksa. Radioaktivni standardi se koriste u svim fazama procesa merenja, uključujući validaciju metoda, kalibraciju i kontrolu kvaliteta. U Laboratoriji za Zaštitu od zračenja i zaštitu životne sredine, Instituta za nuklearne nauke „Vinča” radioaktivni standardi se pripremaju korišćenjem sertifikovanog radioaktivnog rastvora različitih radionuklida. U ovom radu je opisan postupak pripreme radioaktivnih standarda koji obuhvata izbor matriksa, pripremu i spajkovanje pripremljenih matriksa sa sertifikovanim radioaktivnim rastvorom, proveru homogenosti, pakovanje standarda u odgovarajuću geometriju i njihova merenja u kontakt geometriji na gama spektrometru. Za sve materijale matriksa pripremljeni su i uzorci „blenka“ i mereni u istoj geometriji kao i kalibracioni standardi. Nakon analize snimljenih spektara, fitovanjem datih tačaka efikasnosti dobijene su kalibracione krive. U ovom radu dat je i opis budžeta merne nesigurnosti za aktivnosti radionuklida prisutnih u pripremljenim standardima., The routine measurements of environmental samples using gamma-ray spectrometry indicate the needs for preparing radioactive standards for various matrices. The radioactive standards are used in all phases of the measurement process, including method validation, calibration and quality control. In the Radiation and Environmental Protection Departmen in the "Vinča" Institute of Nuclear Sciences, radioactive standards are prepared using a certified radioactive solution of mixed radionuclides. The procedure for radioactive standards preparation, which includes matrix selection and preparation, spiking with a certified radioactive solution, homogeneity check, matrix packing in the appropriate geometry and measurement of the prepared standards using a gamma spectrometer, is described in this paper. For all matrix materials, "blank" samples were prepared in the same manner as the standard materials and measured in the same geometry as the calibration samples. After the analysis of recorded spectra and evaluation of the obtained data for efficiency at given energies, calibration curves were obtained by fitting. The uncertainty budget of the activity for all radionuclides present in the prepared standards is also defined in this paper.

Waste glass can be transformed into a foam by addition of suitable substance (foaming agent) which generated gaseous products by decomposition or reaction at temperatures above its softening temperature (corresponding to a viscosity of 106.6 Pas). This paper provides a concise overview of the latest research in the field of improving the glass foam production process. Some of the possibilities for reducing the environmental impact of glass foam production are also presented. Some of the new production techniques, new foaming agents as well as the possibility of including other solid waste in the composition of glass foams are presented. At the end, the glass foam produced in the Laboratory for glass and ceramics, Institute for Technology of Nuclear and other Mineral Raw Materials, was shown.

This paper presents the effect of K2O content on phase composition of the nanocrystallized niobium germanate glasses. It was shown that the exothermal peak temperature, Tp, shifted toward the higher temperatures with increasing content of K2O. Such increase of K2O content causes a decrease of GeO2 content in the primary phases. The crystals below 100 nm were detected in the samples.

This paper shows the dissolution behavior of polyphosphate glass in demineralized water and 2% citric acid solution at temperatures: 15, 20, 30, 37 and 50 °C. The influence of the solvent type on the diffusion coefficients of the modifying cations, under static conditions, is also presented. The diffusion coefficients, determined from concentration profiles of the modifying cations, are calculated to be in the range of 0.27 to 350x10-14 m2/h for dissolution in demineralized water, and in the range of 3.6 to 148x10-12 m2/h for the dissolution in 2% citric acid solution. The values of activation energy of cations diffusion in demineralized water are in the range from 68.32 to 105.41 kJ/mol, while for 2% citric acid solution they are in the range from 39.28 to 55.34 kJ/mol.

Polyphosphate glasses are a class of bioactive glasses that have gained significant attention in recent years due to their unique properties and potential applications in various fields, particularly in the area of biomedical engineering. These glasses exhibit excellent biocompatibility, which is a crucial requirement for biomaterials. Furthermore, their dissolution and degradation rates can be tailored by modifying their composition, allowing for control over their bioactivity and biodegradability. Polyphosphate glasses also have the ability to form a hydroxyapatite-like layer on their surface when in contact with biological fluids, which facilitates their integration with surrounding tissues. The unique properties of polyphosphate glasses make them promising candidates for various biomedical applications, including bone tissue engineering, drug delivery, and wound healing. This paper presents the thermal characterization of two bioactive polyphosphate glass compositions with the addition of strontium, to investigate the sintering and crystallization processes. The samples were synthesized using the melt-quenching method and then sintered at various temperatures. Differential scanning calorimetry (DSC) and X-ray diffraction (XRD) were used to analyze the thermal behavior and crystalline phases formed during sintering. Our results showed that sintering and crystallization are separate processes for both compositions. The addition of strontium to the glass improved its sintering behavior, resulting in a denser glass structure. Moreover, strontium incorporation did not affect the formation of the crystalline phase during sintering. These findings provide useful insights into the design and development of bioactive polyphosphate glass compositions for bone tissue engineering applications.

Open loop glass recycling is a process where the glass is recycled into a new product. Glass recycling helps reduce landfill waste. Glass takes up significant space in landfills and does not decompose. In many countries, landfills are filling up faster than we can create new ones. Recycling glass reduces the volume of waste, and increases the lifespan of landfills. One of examples of open loop recycling of glass is glass foam produciton. Glass foam production is a process that involves the creation of a light-weight glass material with a foam-like consistency. This type of glass is made by mixing a foaming agent with glass powder and heating to temperatures where decomposition of a foaming agent and sintering of glass happens. This results in the creation of a material that is light, strong, and has thermally-insulating properties. Milled flat glass was mixed with sugar beet factory lime, a CaCO3 – rich waste wich has role of a foaming agent, in order to enter 5% CaCO3 in mixture and pressed at 20 MPa in hydraulic press. Raw pellets were sintered at 800 °C for 30 min. In obtained glass foam phase composition, pore size distribution, compressive strength and thermal conducitivity were determined. Glass foam is emerging as a flexible, cost-effective, and sustainable material that can be utilized in numerous applications to promote sustainable development. Its features such as high insulation capacity, lightweight, and durability make it an ideal material for a wide range of industries.

In previous publications, we pointed out the importance of mannosylation of fibrinogen for the development of cardiovascular complications and fucosylation as a predictor of peritoneal membrane dysfunction in patients on peritoneal dialysis (PD). After a follow-up period of 30 months from the onset of the COVID-19 pandemic, we evaluated the significance of 1,25-dihydroxyvitamin D3 (calcitriol) therapy, primary disease, biochemical and hematologic analyzes, and previously performed glycan analysis by lectin-based microarray as predictors of mortality in this patient group. After univariate Cox regression analysis, diabetes mellitus (DM) and calcitriol therapy were found to be potential predictors of mortality. Additional multivariate Cox regression analysis confirmed that only DM was a predictor of mortality. Nevertheless, the use of calcitriol in therapy significantly reduced mortality in this patient group, as shown by the Kaplan–Meier survival curve. The presence of DM as a concomitant disease proved to be a strong predictor of fatal outcome in PD patients infected with SARS-CoV-2. This is the first study to indicate the importance and beneficial effect of calcitriol therapy on survival in PD patients with COVID-19 infection. In addition, this study points to the possibility that adverse thrombogenic events observed in PD patients during the pandemic may be caused by aberrant fibrinogen glycosylation.

Tritium levels in natural waters today have a similar value to the concentration before thermonuclear bomb testing conducted between 1954 and 1963. Because of the low concentration of this radioisotope, the analysis requires enrichment techniques to produce low detection limit, accurate results and to reduce uncertainties. This analysis includes preliminary distillation, electrolytic enrichment of the samples, the second distillation, and measurement on ultra low-level liquid scintillation spectrometer. The enrichment system consists of 16 electrolytic cells, each with a capacity of 250 ml, placed in the freezer and connected to a direct current source. One cell contains spike water with known tritium concentration and is used for enrichment factor determination. The initial volume for all samples is 250 ml. Na2O2 is used as an electrolyte to make the solution alkaline. Each cell has a gas outlet to ensure the escape of gases H2 and O2. In order to obtain a high enrichment factor, the system works on 5 A, to reduce the initial volume of the samples by 10-15 times. After electrolysis, second distillation must be performed to eliminate electrolyte. 8 ml of water sample after the second distillation is mixed with a scintillation cocktail in polyethylene vials and measured on a liquid scintillation spectrometer Quantulus 1220. At the end of the electrolytic enrichment process, the final volumes of the samples can be different, which causes different enrichment between the cells. To eliminate this influence, the final volume of all enrichment samples can be normalized at one value. In order to determine the corrected count rates obtained for each sample, the separation factor must be first calculated, taking into account initial volume, normalized final volume, count rate for spike water (after enrichment), count rate for spike water (before enrichment), and background count rate. In the example of one electrolysis, with 15 samples of drinking water, precipitation, and s

The paper presents three-dimensional numerical models of short concrete-filled steel tubular circular columns that can successfully describe the column behaviour under axial compression. Several of the most commonly used material models for the steel part and a concrete portion of the column are evaluated in the models. In addition, the paper presents a new proposal for the extension of the Eurocode 2 stress-strain relation to make it suitable for describing the complex behaviour of concrete inside the steel tube. This model overcomes the current limitations of the Eurocode 2 design guide, referring to the limitation for the concrete curve in compression to 3.5‰ strain. The ultimate axial column strength obtained by the proposed model is compared to the ultimate column capacity calculated by a simplified method provided in Eurocode 4. All presented numerical models are validated on a set of experiments from the literature and demonstrate good agreement. The comments about the accuracy of each model are provided, along with the identified limitations.

Ground Air Radioactivity Monitoring (GRAMON) database is a recently established collection containing activity concentrations of gamma emitters in aerosol samples. The measurements come from Serbia (sampling site Belgrade), Slovenia (sampling sites Ljubljana and Krško), Bosnia and Herzegovina (sampling site Sarajevo), Montenegro (sampling site Podgorica), and North Macedonia (sampling sites Skopje and Bitola), thus covering the northern and central parts of the Balkan Peninsula. As a database arising from the monitoring programmes in several countries, GRAMON is not fully homogeneous in terms of the radionuclides and time periods studied. For example, the beryllium-7 records are available for all sampling sites, while the lead-210 records only in Serbia, Slovenia, and Bosnia and Herzegovina. The time series for Serbia and Slovenia began in 1991, for Montenegro and North Macedonia in 2008, and for Bosnia and Herzegovina in 2010. However, sampling, sample preparation, and measurement procedures across the sites and laboratories are similar. In brief, aerosol samples are collected on filter papers using air samplers. Activity concentrations of radionuclides are determined by standard gamma spectrometry using high-purity germanium detectors. The time series contain monthly mean activity concentrations. Since only some of the GRAMON records have been previously published, this database provides a source for radioactivity research in the region that has been underrepresented in large-scale studies. We further hope to expand the number of contributing laboratories and cover a wider region of Europe, especially its southern and eastern parts.

This work presents the natural radioactivity distribution of 21 surface soil samples taken in the city of Novi Sad, Serbia. The analysis for radioactivity was performed using a gas low-level proportional counter for gross alpha and gross beta activity, while the specific activities of radionuclides were determined using HPGe detectors. The gross alpha activity of 20 samples was below the minimum detectable concentration (MDC), while in 1 sample it was 243 Bq kg−1; the gross beta activity ranged from the MDC (11 samples) to 566 Bq kg−1. The gamma spectrometry measurements showed naturally occurring radionuclides 226Ra, 232Th, 40K, and 238U in all investigated samples, with average values (Bq kg−1) of 33.9, 36.7, 513.8, and 34.7, respectively. Natural radionuclide 235U was detected in 18 samples with activity concentrations in the range of 1.3–4.1 Bq kg−1, while in the other 3 samples, the values were below the MDC. The artificial 137Cs radionuclide was detected in 90 percent of the samples, with a maximum value of 21 Bq kg−1, while the other artificial radionuclides were not detected. Based on the obtained concentrations of natural radionuclides, hazard indexes were estimated, and radiological health risk was assessed. The results present the absorbed gamma dose rate in the air, annual effective dose, radium equivalent activity, external hazard index, and lifetime cancer risk.