Contemporary Materials最新文献

{"title":"EMERGENCE OF ORDERED MOTION OF THE OSCILLATOR DRIVEN BY FLUCTUATING FORCE","authors":"Z. Rajilić, N. Stupar, Tatjana Vujičić, S. Lekić","doi":"10.7251/comen2002122r","DOIUrl":"https://doi.org/10.7251/comen2002122r","url":null,"abstract":"Computational experiments with double pendulum, Tacker’s oscillator and steel beam, described by Duffing equations, are performed. We assume that a fluid drives the oscillator by fluctuating force. The considered complex motion is a combination of deterministic chaos and stochasticity. If amount of the fluctuating force is large enough (the number of fluid particles interacting with the oscillator is then large), oscillator motion becomes ordered. Similar result is obtained in the Lorenz model, when considering a part of the Earth atmosphere interacting with surrounding air.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86542653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EVALUATION OF RADIOACTIVITY IN THE PHOSPHOGYPSUM STOCKPILE OF “HIV” VELES, THE REPUBLIC OF NORTH MACEDONIA","authors":"Mitko Janchev, I. Boev, Z. Stojanovska, B. Boev","doi":"10.7251/comen2001027j","DOIUrl":"https://doi.org/10.7251/comen2001027j","url":null,"abstract":"The production of phosphoric acid from natural phosphate ore generates an industrial waste product named phosphogypsum. Phosphogypsum contains considerable amounts of natural radionuclides from the 238U chain, originating from the ore but enriched during the technological process. In order to perform radiological characterization of the “HIV” (Chemical Industry Veles) phosphogypsum stockpile, five phosphogypsum samples were collected and analyzed. The mean values of gross alpha and beta specific activities ± standard deviation values were: (950±104) Bq/kg and (1694±220) Bq/kg, respectively. Further analysis showed increased gross activities of radionuclides of the 238U chain, while the radionuclides of the 232Th chain and 40K were below the detection limit. The mean values of the specific activities of 238U and 226Ra were (360±55) Bq/kg and (280±84) Bq/kg, respectively. The estimated annual outdoor effective dose, at 1m received by adults was 0.25 mSv/y, which is below a dose limit of 1 mSv/y for members of general public. The results obtained in this study show that radionuclides, although present in relatively high concentrations in the phosphogypsum pile, do not imply an increased external radiation risk for members of the population. The possible use of phosphogypsum in civil construction and agriculture may not be excluded if conditions of prior good planning taking into account the radionuclides activities exist.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90988203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FIRST RESULTS OF RADON MONITORING PROGRAM IN SLOVENIA ACCORDING TO EU EURATOM DIRECTIVE","authors":"G. Omahen","doi":"10.7251/comen2001039o","DOIUrl":"https://doi.org/10.7251/comen2001039o","url":null,"abstract":"In 2018 Slovenia adopted the new ordinance where the requirements of the Council of the European Union 2013/59 Euratom on radon were taken into account (2LIT). As the new ordinance requires systematic survey of radon concentrations in public institutions and dwellings in Slovenia, Ministry of Health announced two tenders for the radon surveys in 2018 and 2019. Zavod za varstvo pri delu (ZVD) successfully competed on both tenders. The tenders required measurements of radon concentrations in public institutions, mainly schools and kindergartens and in private dwellings every year in 24 municipalities which were recognised as radon prone areas. Besides these measurements ZVD as the authorised organisation measured radon concentration in companies all over Slovenia and private dwellings where owners wanted to know how high the radon concentration is and if some actions are required to lower it. The radon concentrations were measured with track etched detectors. The results of the survey are presented in the article as well as the difficulties we encountered during sending track etched detectors to people.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"70 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86557425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE INDOOR RADON AND THORON CONCENTRATIONS IN SCHOOLS OF SKOPJE (REPUBLIC OF NORTH MACEDONIA) AND BANJA LUKA (REPUBLIC OF SRPSKA) CITIES MEASURED BY RADUET DETECTORS","authors":"Z. Stojanovska, Z. Curguz, P. Kolarž, Z. Žunić, I. Boev, B. Boev","doi":"10.7251/comen2001020s","DOIUrl":"https://doi.org/10.7251/comen2001020s","url":null,"abstract":"Radon (222Rn) and thoron (220Rn) are natural radioactive gases, generated in the terrestrial materials. They are the main sources of public exposure to ionising radiation in any of indoor environment worldwide. Differences in half-lives of 222Rn (T1/2 = 3.8 d) and 220Rn (T1/2 = 55.6 s) lead to its different indoor behavior. Several studies of indoor 222Rn and 220Rn in Northern Macedonia have been performed, starting with measurements in dwellings in 2008 and continuing with measurements in schools during 2012. The surveys in the Republic of Srpska began later (in 2011) with the simultaneous 222Rn and 220Rn measurements in the dwellings and schools of Banja Luka cities. This paper, as a result of our cooperation, summarizes the results and general conclusions obtained from 222Rn and 220Rn measurements in schools of capitals. In both cities, the measurements were made using Raduet - nuclear track detectors; deployed at distances: >0.5m (Skopje) and 0.2m (Banja Luka); and exposed in a period: March 2012 - May 2012 (Skopje) and April 2011 - May 2012 (Banja Luka). Results for 222Rn and 220Rn concentrations in both cities have a log-normal distribution. The 222Rn geometric mean value of 71 Bq/m3 in Skopje is higher than in Banja Luka city (GM = 50 Bq/m3). Among different radon potential in the cities, this difference could be related to the different exposure time of detectors. Furthermore, the dispersion of the 222Rn results in each city expressed through geometric standard deviation is relatively low: GSD = 2.13 (Skopje) and GSD = 2.11 (Banja Luka) indicating relatively homogeneous data sets. The 220Rn concentrations in Banja Luka (GM = 51 Bq/m3) were higher than in Skopje (GM = 11 Bq/m3). It is obvious that in the case of 220Rn, the exposure period did not play a significant role. One of the reasons for this difference could be the position of the detectors as well as the different building materials in the schools. On the contrary, the dispersion of the 220Rn results in Skopje (GSD = 3.38) was greater than in Banja Luka (GSD = 2.07).","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"86 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77566517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MEASUREMENT OF RADON ACTIVITY CONCENTRATION IN BUILDING MATERIALS USED IN BOSNIA AND HERCEGOVINA","authors":"Ema Sinanović, F. Adrović, Amira Kasumović, Amela Kasić","doi":"10.7251/comen2001051a","DOIUrl":"https://doi.org/10.7251/comen2001051a","url":null,"abstract":"Man is continuously exposed to ionizing radiation because of the presence of naturally occurring radioactive materials (NORM) in the environment. Various technological processes of processing and using of materials that contain natural radionuclides generate materials of enhanced natural radioactivity (TENORM). The largest contribution to irradiance with natural sources of ionizing radiation is the exposure of the population to indoor radon. This gas originates from the radioactive decay of 226Ra and 224Ra that are present in the soil under houses and building materials. Depending on the type of building materials, indoor exposure to radon at dwellings and workplaces can be over a thousand times greater than in outdoor space. In Bosnia and Herzegovina, no valid and comprehensive radiological studies on the building materials have been performed that would guarantee for their dosimetric safety use for installation in residential and industrial buildings, highways, as well as their application for other purposes. The quantification of the radon levels that comes from building materials is a necessary and very important part of the global protection of the population from ionizing radiation. This paper presents the first results of a study on the radon activity concentrations in building materials used in Bosnia and Herzegovina. Measurements were performedwith a professional Alpha GUARD system. The mean values of the activity concentration of the exhaled radon of investigated building materials varied from 10 Bqm-3 to 101 Bqm-3, radon exhalation rate values ranged from 77.0 mBqm-2h-1 to 777.7 mBqm-2h-1. Gamma dose rate was in the range 57–112 nSv h−1.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82462169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RADON SURVEY IN THE BUILDINGS OF PRE-UNIVERSITY EDUCATION IN MONTENEGRO","authors":"R. Zekić, P. Vukotic, Tomislav Andjelić, N. Svrkota","doi":"10.7251/comen2001009v","DOIUrl":"https://doi.org/10.7251/comen2001009v","url":null,"abstract":"During the academic year 2016/17 (September − June), radon was surveyed in all 519 buildings of the pre-university education in Montenegro – primary, high and vocational schools, kindergartens, institutes for children with special needs and student dormitories. Radon detectors (Radosys,RSFV type) were placed in all classrooms, rooms occupied by children and offices on ground floor, and in some rooms on the upper floors. The total number of detectors was 4078, of which 285 were duplicate (control) detectors. During the radon survey, 11.4% of the detectors were lost or damaged. Average 9-month radon activity concentrations were obtained for 3345 rooms in 507 buildings. Mean values of radon concentrations in the rooms were AM = 243 Bq/m3 and GM = 142 Bq/m3, while the corresponding values for Montenegrin dwellings, found in the national radon survey, were more than twice lower. Radon concentrations above 300 Bq/m3 were found in 23.3% of all surveyed rooms and in 3.4% of the rooms they were above 1000 Bq/m3. Radon activity concentrations above 300 Bq/m3 were measured in some rooms in 44% of the buildings, and those above 1000 Bq/m3 in 9.5% of the buildings. Radon levels in educational buildings are significantly higher than in Montenegrin homes, which means that children and educators are more exposed to the harmful effects of radon in schools and kindergartens than at homes (for equal durations of stay in them). This could be resulting from the type of construction of educational buildings, which are usually large low-rise structures, and from a relatively high average age of these buildings.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79923903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RADON IN NIŠKA BANJA SPA WATERS","authors":"I. Radonjić, T. Pavlovic, D. Mirjanić, Anđelina Marić","doi":"10.7251/comen2001046r","DOIUrl":"https://doi.org/10.7251/comen2001046r","url":null,"abstract":"The most numerous investigations of radon concentration in waters in Serbia were conducted in Niška Banja spa. Niška Banja spa is considered an area with high natural radioactivity. The appearance of radon in water is due to the leaching of soil in which 226Ra nuclei decompose. The passage of groundwater through radium-rich rocks results in the collection of radium decay products, including radon 222Rn. This paper presents the results of several studies which measured radon concentrations in the waters of Niška Banja spa. There are three thermal springs in Niška Banja spa: „Glavno vrelo“, „Suva banja” and „Školska česma”. The radon concentration in the waters of Niška Banja spa was found to be generally about 0.4-570·103 Bq/m3. According to the available data in the literature, the highest measured radon concentration in the waters of Niška Banja spa is 1463.4·103 Bq/m3.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89733515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RADON IN THE WATER","authors":"Jelena Vulinović, Srđan Vuković, S. Pelemiš, D. Rajić","doi":"10.7251/comen2001062v","DOIUrl":"https://doi.org/10.7251/comen2001062v","url":null,"abstract":"Man and his environment are constantly exposed to the effects of ionizing radiation. Most of this radiation comes from natural and artificial radionuclides and the biggest radioecological problem is the 222Rn radioactive gas. Natural radioactivity comes from unstable radioisotopes that were present during the formation of the Earth, and are present today. According to the research by UNSCEAR(United Nations Scientific Committee on the Effects of Atomic Radiation) it is estimated that the radiation dose, which comes from natural radionuclides and to which man is exposed, is 2.4 mSv per year. Natural sources of radioactivity are cosmic radiation and Earth’s crust that contains primordial radioactive elements including those that are sources of radon (uranium). Radon is a natural inert radioactive gas without smell and taste. It is soluble in water and can easily diffuse with the gaseous and aqueous phase and in this way forms significant concentrations. The techniques and methods most commonly used to detect and determine the activities of radon in water are alpha spectrometry, gamma spectrometry and measurement techniques on a liquid scintillation detector. Throughout epidemiological studies, the World Health Organization has provided convincing evidence of the correlation of exposure to indoor radon and the development of lung cancer. Radon and its decomposition products are considered to be the second cause of lung cancer after consuming tobacco.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"93 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75615404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LONG-TERM MEASUREMENTS OF EQUILIBRIUM EQUIVALENT RADON AND THORON PROGENY CONCENTRATIONS IN REPUBLIC OF SRPSKA DWELLINGS","authors":"Z. Curguz, Z. Stojanovska, R. Mishra, B. K. Sapra, I. Yarmoshenko, P. Kolarž, D. Mirjanić, A. Janićijević, Z. Žunić","doi":"10.7251/comen2001033c","DOIUrl":"https://doi.org/10.7251/comen2001033c","url":null,"abstract":"The long–term measurements of radon and thoron equilibrium equivalent concentrations (EERC and EETC) were carried out the first time in Republic of Srpska in 25 schools of its capital Banja Luka and in its wider surroundings. After this successful survey, the measurements continued using the same type of the LR 115 nuclear track detectors, i.e., Direct Radon Progeny Sensors/Direct Thoron Progeny Sensors (DRPS/DTPS), and they were deployed in the 36 dwellings nearby the investigated schools. The detectors were exposed for one year period at 15–20 cm distance from the walls. The EERC and EETC were found to vary in the range from 6.3 to 14.4 Bq/m3and from 0.10 to 1.1 Bq/m3, with geometric mean 9.3 and 0.36, respectively. The same variance of EER and EET concentrations, measured in living and bedrooms of buildings built with different construction materials as well at different floors have been obtained. The insignificant correlations between EERC and EETC, show that these concentrations appeared to be independent in investigated dwellings. The calculated ratio of EETC to EERC ranged from 0.01 to 0.16 with the geometric mean of 0.04. The aim of this study is to give possible scientific contribution considering the explanation of EERC and EETC behavior in an indoor environment.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74801310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A SHORT SUMMARY OF PAST AND RECENT ACTIVITIES ON PROTECTION FROM RADON EXPOSURE CARRIED OUT BY THE ITALIAN NATIONAL INSTITUTE OF HEALTH","authors":"M. Ampollini, F. Bochicchio, S. Antignani, B. Caccia, M. Caprio, C. Carpentieri, C. Di Carlo, C. Nuccetelli, S. Pozzi, S. Valentini, G. Venoso","doi":"10.7251/comen2001001b","DOIUrl":"https://doi.org/10.7251/comen2001001b","url":null,"abstract":"The Italian National Institute of Health (Istituto Superiore di Sanità ‒ ISS) has a long experience of activities concerning protection from radon exposure (measuring techniques, surveys in dwellings and other environments, public information, training courses, epidemiological studies and risk evaluation, etc.) with the first activities dating back to the eighties. On the basis of this expertise, the ISS has also contributed to radon policies and regulations, in particular to the development of the first Italian National Radon Action Plan (INRAP) in 2002 and its coordination in the following years, as well as to international regulations and recommendations. Many activities have been carried out with significant collaborations not only with Italian agencies and institutes, but also with some other countries as well as with international organizations (e.g. WHO). In this paper, a short summary of the past activities carried out by the ISS on several radon issues is presented. Moreover, some of the recent and current activities and projects are shortly described, taking into account the requirements of the Council Directive 2013/59/Euratom, including design of radon surveys, quality of both active and passive measurements, evaluation of actual public exposure, and cost-effectiveness evaluations.","PeriodicalId":10617,"journal":{"name":"Contemporary Materials","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82749592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}