ECE laboratory in the Vinča institute: Its basic characteristics and fundamentals of electrochemic etching on polycarbonate

This paper deals with the introductory aspects of the Electrochemical Etching Laboratory installed at the VINČA Institute in the year 2003. The main purpose of the laboratory is its field application for radon and thoron large-scale survey using passive radon/thoron UFO type detectors. Since the etching techniques together with the laboratory equipment were transferred from the National Institute of Radiological Sciences, Chiba, Japan, it was necessary for both etching conditions to be confirmed and to be checked up^ i. e., bulk etching speeds of chemical etching and electrochemical etching in the VINCA Electrochemical Etching Laboratory itself. Beside this initial step, other concerns were taken into consideration in this preliminary experimental phase such as the following: the measurable energy range of the polycarbonate film, background etch pit density of the film and its standard deviation and reproducibility of the response to alpha particles for different sets of etchings

A survey of indoor radon concentrations in Gora district, Kosovo and Metohija

Godišnja merenja radona u zatvorenim prostorijama izvedena su u 20 uglavnom prizemnih kuća u regionu Gore, u južnom delu Kosova i Metohije. CR-39 Gammadata detektori su postavljani u dnevnim i spavaćim sobama. Godišnja koncentracija radona u dnevnim sobama kretala se u rasponu od 26 do 315 Bq m-3 sa srednjom vrednošću od 85,7 Bq m-3 , a u spavaćim sobama u rasponu od 28 do 448 Bq m-3 sa srednjom vrednošću 75,6 Bq m- 3. Distribucije izmerenih koncentracija radona u dnevnim i spavaćim sobama imaju očekivani lognormalni oblik; Mann-Whitney test je potvrdio da ne postoji značajna razlika između koncentracija radona u različitim sobama. Najveće izmerene vrednosti koncentracije radona u obe sobe su u kući izgrađenoj od kamena i betona.Annual indoor radon measurements were carried out in two rooms of 20 mostly ground floor dwellings in Gora District, Southwestern part of Kosovo and Metohija. The CR-39 Gammadata detectors were placed in the living rooms and bedrooms. Annual radon concentration in the living rooms range from 26 to 315 Bq m-3 with a mean value of 85.7 Bq m-3, while the same one in bedrooms range from 28 to 448 Bq m-3 with mean value of 75.6 Bq m-3. The distributions of radon concentration measured in living rooms and bedrooms follow the expected lognormal shape; Mann-Whitney test confirmed no significant systematic difference between radon concentrations in the two room types appears. The highest value of radon concentration in both rooms was in dwelling built from stone and concrete

A survey of indoor radon concentrations in Gora district, Kosovo and Metohija

Godišnja merenja radona u zatvorenim prostorijama izvedena su u 20 uglavnom prizemnih kuća u regionu Gore, u južnom delu Kosova i Metohije. CR-39 Gammadata detektori su postavljani u dnevnim i spavaćim sobama. Godišnja koncentracija radona u dnevnim sobama kretala se u rasponu od 26 do 315 Bq m-3 sa srednjom vrednošću od 85,7 Bq m-3 , a u spavaćim sobama u rasponu od 28 do 448 Bq m-3 sa srednjom vrednošću 75,6 Bq m- 3. Distribucije izmerenih koncentracija radona u dnevnim i spavaćim sobama imaju očekivani lognormalni oblik; Mann-Whitney test je potvrdio da ne postoji značajna razlika između koncentracija radona u različitim sobama. Najveće izmerene vrednosti koncentracije radona u obe sobe su u kući izgrađenoj od kamena i betona.Annual indoor radon measurements were carried out in two rooms of 20 mostly ground floor dwellings in Gora District, Southwestern part of Kosovo and Metohija. The CR-39 Gammadata detectors were placed in the living rooms and bedrooms. Annual radon concentration in the living rooms range from 26 to 315 Bq m-3 with a mean value of 85.7 Bq m-3, while the same one in bedrooms range from 28 to 448 Bq m-3 with mean value of 75.6 Bq m-3. The distributions of radon concentration measured in living rooms and bedrooms follow the expected lognormal shape; Mann-Whitney test confirmed no significant systematic difference between radon concentrations in the two room types appears. The highest value of radon concentration in both rooms was in dwelling built from stone and concrete

Analysis of specific radionuclides activity variations in soil within geotectonic units of Republic of North Macedonia

To establish baseline values for concentrations of terrestrial radionuclides for the Republic of North Macedonia, a survey covering the entire territory was performed. The 213 soil samples were collected from regions around the major settlements and cities, approximately evenly distributed over the geotectonic units which constitute the country's geological foundation. The specific activities of radionuclides were measured by gamma spectrometry. The following geometric mean values and geometric standard deviations were obtained: 550 Bqkg(-1) (1.47) for K-40, (37) Bqkg(-1) (1.33) for Ra-226, 38 Bqkg(-1) for U-238, and 38 Bqkg(-1) (1.53) for Th-232 in dry soil. The relation between specific activities of natural radionuclides and geology was investigated. Correlation between radionuclides, which may serve as additional geochemical indicators, and geology could not be found convincingly,. Mutual correlations between Ra-226, U-238, and Th-232 activities were found to be high (Spearman rho about 0.8), whereas the ones between these and K-40 are a bit lower, somewhat above rho = 0.6

Factors affecting indoor radon variations: A case study in schools of eastern macedonia

The subject of this study is the radon concentrations variations, measured with a nuclear track detectors in a total of 58 premises in all 29 primary schools of 4 municipalities in the Eastern part of the Republic of Macedonia. Despite a relatively small territory, the variability of radon concentrations proved to be significant. The geometric means (geometric standard deviations) of radon concentrations in the examined municipalities were in the range from GM = 71 Bq/m 3 (GSD = 2.08) to GM = 162 Bq/m 3 (GSD = 2.69), while for the entire region it was: GM = 96 Bq/m 3 (GSD = 2.47). The influence of the geographical and geological features of the school site as well as the building characteristics on the radon variations were investigated. The analysis showed that type of municipality, building materials, basement and geology have significant effects and respectively describe 6%, 16%, 22%, 39% of the radon total variability

High annual radon concentration in dwellings and natural radioactivity content in nearby soil in some rural areas of Kosovo and Metohija

Some previous studies on radon concentration in dwellings of some areas of Kosovo and Metohija have revealed a high average radon concentration, even though the detectors were exposed for three months only. In order to better design a larger study in this region, the annual measurements in 25 houses were carried out as a pilot study. For each house, CR-39-based passive devices were exposed in two rooms for the two consecutive six-month periods to account for seasonal variations of radon concentration. Furthermore, in order to correlate the indoor radon with radium in nearby soil and to improve the knowledge of the natural radioactivity in the region, soil samples near each house were collected and 226Ra, 232Th, 40K activity concentration were measured. The indoor radon concentration resulted quite high from the average (163 Bq/m3) and generally it did not differ considerably between the two rooms and the two six-month periods. The natural radionuclides in soil resulted to be distributed quite uniformly. Moreover, the correlation between the226Ra content in soil and radon concentration in dwellings resulted to be low (R2=0.26). The annual effective dose from radon and its short-lived progeny (5.5 mSv, in average) was calculated by using the last ICRP dose conversion factors. In comparison, the contribution to the annual effective dose of outdoor gamma exposure from natural radionuclides in soil is nearly negligible (66 mSv). In conclusion, the observed high radon levels are only partially correlated with radium in soil; moreover, a good estimate of the annual average of radon concentration can be obtained from a six-month measurement with a proper choice of exposure period, which could be useful when designing large surveys

Design, Analysis, and Fabrication of a Snake-Inspired Robot with a Rectilinear Gait

Snake-inspired robots display promise in areas such as search, rescue and reconnaissance due to their ability to locomote through tight spaces. However, several specific issues regarding the design and analysis must be addressed in order to better design them. This thesis develops kinematic and dynamic models for a class of snake-inspired gait known as a rectilinear gait, where mechanism topology changes over the course of the gait. A model using an Eulerian framework and Coulomb friction yields torque expressions for the joints of the robot. B-spline curves are then used to generate a parametric optimization formulation for joint trajectory generation. Exact gradient computation of the torque functions is presented. A parametric model is used to describe the performance effects of changing system parameters such as mass, length, and motor speed. Finally, a snake-inspired robot is designed and fabricated in order to demonstrate both the vertical rectilinear gait and a modular, molded design aimed at reducing the cost of fabrication

Factors affecting indoor radon variations: A case study in schools of eastern macedonia

The subject of this study is the radon concentrations variations, measured with a nuclear track detectors in a total of 58 premises in all 29 primary schools of 4 municipalities in the Eastern part of the Republic of Macedonia. Despite a relatively small territory, the variability of radon concentrations proved to be significant. The geometric means (geometric standard deviations) of radon concentrations in the examined municipalities were in the range from GM = 71 Bq/m 3 (GSD = 2.08) to GM = 162 Bq/m 3 (GSD = 2.69), while for the entire region it was: GM = 96 Bq/m 3 (GSD = 2.47). The influence of the geographical and geological features of the school site as well as the building characteristics on the radon variations were investigated. The analysis showed that type of municipality, building materials, basement and geology have significant effects and respectively describe 6%, 16%, 22%, 39% of the radon total variability

Prediction of Long-Term Indoor Radon Concentration Based on Short-Term Measurements

We present a method for the estimation of annual radon concentration based on short-term (three months) measurements. The study involves results from two independent sets of indoor radon concentration measurements performed in 16 cities of the Republic of Macedonia. The first data set contains winter and annual radon concentration obtained during the National survey in 2010 and the second, contains only the radon concentration measured during the winter of 2013. Both data sets pertain to radon concentration from the same cities and have been measured applying the same methodology in ground floor dwellings. The results appeared to be consistent and the dispersion of radon concentration was low. Linear regression analysis of the radon concentration measured in winter of 2010 and of the 2010 annual radon concentration revealed a high coefficient of determination R-2 = 0.92, with a relative uncertainty of 3%. Furthermore, this model was used to estimate the annual radon concentration solely from winter-term measurements performed in 2013. The geometrical mean of the estimated annual radon concentration of the 2013: radon concentration (A-2013) =98 Bqm(-3) was almost equal to the geometrical mean of the annual radon concentration from the 2010, radon concentration (A-2010) = 99 Bqm(-3). Analysis of the influence of building characteristics, such as presence/absence of a basement in the building, or the dominant building material on the estimated annual radon concentration is also reported. Our results show that a low number of relatively short-term radon measurements may produce a reasonable insight into a gross average obtained in a larger survey

A Comparison of Retrospective Radon Gas Measurement Techniques Carried Out in the Serbian Spa of Niska Banja

Indoor radon retrospective concentrations were obtained and compared using two radon measurement methods. Both methods rely on the measurement of the long-lived radon progeny (210)Pb, collected either on the surfaces (surface trap technique), most frequently glass, or in a volume trap, usually sponge from furniture (volume trap technique). These techniques have been used to retrospectively estimate radon gas concentrations that have existed in dwellings in the past. The work presented here compares the results provided by the surface trap technique devised at the University College of Dublin, Ireland, and the volume trap technique devised at the Scientific Research Center, Mol, Belgium. The field campaign was carried out by the research team of the ECE Laboratory of the Vinca Institute of Nuclear Sciences at the spa of Niska Banja, identified as a region of Serbia with a high indoor radon and ground water radium and radon content