Analysis of the Radiopollution of the City of Sarajevo and its Surrounding Area with Regard to Radionuclides

U posljednje vrijeme postoje razne kalkulacije o streljivu koje koristi osiromašeni uranij, a koje je upotrebljavano tijekom rata u Bosni i Hercegovini (1992.-1995.). Pored toga, područje Bosne i Hercegovine bilo je pod izravnim utjecajem globalnih disperzijskih procesa u razdoblju mjeseca svibnja 1986. godine, kao posljedica emisije iz Nuklearne elektrane "Lenin" u Černobilu. Cilj istraživanja bio je odrediti specifičnu radioaktivnost: 238U, 226Ra, 210Pb, 232Th, 40K i 137Cs u površinski uzetim uzorcima tla u gradu Sarajevu i njegovoj okolici. Uzorci tla uzeti su s devet lokaliteta u gradu Sarajevu i njegovoj okolici. Upotrebljavan je detektor Ge HP spojen na Ortec MCA Gamma Vision 32 Software kao i instrumentna neutronska aktivacijska tehnika (INAA). Rezultati analize uspoređeni su s raspoloživim podacima za grad Sarajevo (1986.,1987.,1988. godina) i Sloveniju. Ti podaci se odnose na razdoblje odmah nakon katastrofe u Černobilu. Gotovo kod svih analiziranih radionuklida imamo neznatno višu specifičnu radioaktivnost u odnosu na podatke iz 1986., 1987. i 1988. godine za grad Sarajevo. Naši rezultati ne odstupaju od vrijednosti dobivenih u Sloveniji, osim u slučaju 137Cs na lokalitetu Vraca, gdje je znatno viša specifična radioaktivnost i iznosi α = 460±20 Bq kg-1.In recent years, great attention has been focused on the research of problems related to the environment and processes occurring within it. The accident that occurred at Nuclear Power Plant in Chernobyl (1986) unquestionably warned that global pollution with radioactive substances on a continent scale may be expected. The past twenty years have been marked with the utilization of metal uranium – a depleted isotope of uranium-235 for various purposes. Today, depleted uranium has found its use in modern armies and it is used as efficient ammunition against armored military systems. There are estimates about the usage of ammunition with depleted uranium deployed in Bosnia and Herzegovina during the war (1992–1995). The region of Bosnia and Herzegovina was exposed to the direct influence of the global dispersion processes that had occurred in May 1986 as a consequence of emissions originating from Nuclear Power Plant “Lenin” in Chernobyl. In this work the radionuclides fraction analysis (238U, 226Ra, 210Pb, 232Th, 40K i 137Cs) of surface samples (0–5 cm) originating from the City of Sarajevo and its surroundings has been presented. The soil samples were taken from nine locations in the city and the surrounding area: Blekin potok, Kobilja glava, Bentbaša, Vraca, Prirodno-matematieki fakultet (PMF), Aziai, Hrasnica, Butmir, and Blažuj. The analyses were performed at the Department for Environment of Jo?ef Štefan Institute in Ljubljana, Slovenia. Ge HP detector connected to Ortec MCA Gamma Vision 32 Software was used in addition to the Instrumental Neutron Activation Technique (INAA). The results of the analysis were compared with data available for the City of Sarajevo (years 1986, 1987 and 1988) and Slovenia. Analyses were made after Chernobyl catastrophe. Almost all of radionuclides analysed have shown to have a slightly higher specific radioactivity when compared to the data obtained in 1986, 1987 and 1989 for the City of Sarajevo. Our results are in accordance with the values obtained in Slovenia except in the case of 137Cs at location Vraca, where a significantly higher concentration has been observed and reaching α = 460 ± 20 Bq kg–1

The peculiarities of cross-correlation between two secondary precursors - radon and magnetic field variations, induced by stress transfer changes

A model of precursor manifestation mechanisms, stimulated by tectonic activity and some peculiarities of observer strategy, whose main task is the effective measurement of precursors in the spatial area of their occurrence on the Earth's daylight, are considered. In particular, the applicability of Dobrovolsky's approximation is analyzed, when an unperturbed medium (characterized by the simple shear state) and the area of tectonic activity (local inhomogeneity caused by the change only of shear modulus) are linearly elastic, and perturbation, in particular, surface displacement is calculated as a difference of the solutions of two independent static problems of the theory of elasticity with the same boundary condition on the surface. Within the framework of this approximation a formula for the spatial distribution (of first component) of magnetic field variations caused by piezomagnetic effect in the case of perturbed regular medium, which is in simple shear state is derived. Cogent arguments in favor of linear dependence between the radon spatial distribution and conditional deformation are obtained. Changes in magnetic field strength and radon concentrations were measured along a tectonomagnetic profile of the total length of 11 km in the surroundings of the "Academician Vernadsky" Station on the Antarctic Peninsula (W 64{\deg}16', S 65{\deg}15'). Results showed a positive correlation between the annual surface radon concentration and annual changes of magnetic field relative to a base point, and also the good coincidence with theoretical calculation.Comment: 27 pages, 11 figures, 3 tables (a substantially revised and extended edition; v3 -- some analysis of recent publications added

Opening a new window to other worlds with spectropolarimetry

A high level of diversity has already been observed among the planets of our own Solar System. As such, one expects extrasolar planets to present a wide range of distinctive features, therefore the characterisation of Earth- and super Earth-like planets is becoming of key importance in scientific research. The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission proposal of this paper represents one possible approach to realising these objectives. The mission goals of SEARCH include the detailed characterisation of a wide variety of exoplanets, ranging from terrestrial planets to gas giants. More specifically, SEARCH will determine atmospheric properties such as cloud coverage, surface pressure and atmospheric composition, and may also be capable of identifying basic surface features. To resolve a planet with a semi major axis of down to 1.4AU and 30pc distant SEARCH will have a mirror system consisting of two segments, with elliptical rim, cut out of a parabolic mirror. This will yield an effective diameter of 9 meters along one axis. A phase mask coronagraph along with an integral spectrograph will be used to overcome the contrast ratio of star to planet light. Such a mission would provide invaluable data on the diversity present in extrasolar planetary systems and much more could be learned from the similarities and differences compared to our own Solar System. This would allow our theories of planetary formation, atmospheric accretion and evolution to be tested, and our understanding of regions such as the outer limit of the Habitable Zone to be further improved.Comment: 23 pages, accepted for publication in Experimental Astronom

Research on air pressure drop in helically-finned tube heat exchangers

In order to establish a reliable procedure for estimation of air pressure drop, extensive investigation of the open literature has been conducted. The equations from mostly cited literature sources were tested against the experimental data given in the open literature and certain level of uncertainty was found. Using published experimental data, new correlations for estimation of air pressure drop in helically-finned tube bundles with in-line and staggered tube arrangement have been established. Chosen form of correlations successfully describes operating regimes for wide range of Reynolds number and geometrical parameters

Research on the air pressure drop in plate finned tube heat exchangers

In order to establish a reliable procedure for estimation of air pressure drop, experiments on plate finned tube heat exchangers have been conducted, as well as the research on the open literature. The procedure of Kays and London was tested against the experimental data and significant level of uncertainty was found. Using own experimental data, as well as previously published data of Kays and London, new correlation for estimation of air pressure drop has been established. Statistical parameters of new correlation enable the conclusion that it can be used for wide range of Reynolds numbers

Research on air pressure drop in helically-finned tube heat exchangers

In order to establish a reliable procedure for estimation of air pressure drop, extensive investigation of the open literature has been conducted. The equations from mostly cited literature sources were tested against the experimental data given in the open literature and certain level of uncertainty was found. Using published experimental data, new correlations for estimation of air pressure drop in helically-finned tube bundles with in-line and staggered tube arrangement have been established. Chosen form of correlations successfully describes operating regimes for wide range of Reynolds number and geometrical parameters

Research on the air pressure drop in plate finned tube heat exchangers

In order to establish a reliable procedure for estimation of air pressure drop, experiments on plate finned tube heat exchangers have been conducted, as well as the research on the open literature. The procedure of Kays and London was tested against the experimental data and significant level of uncertainty was found. Using own experimental data, as well as previously published data of Kays and London, new correlation for estimation of air pressure drop has been established. Statistical parameters of new correlation enable the conclusion that it can be used for wide range of Reynolds numbers

Distributed hydrological-hydraulic modeling of the karst polje water balance

The paper presents developed 3Dnet-HET, a distributed hydrologic model coupled with the discrete channel network concept for groundwater circulation simulation in the karst environment. The hydrologic part is driven by the spatially distributed precipitation input and characteristic air temperatures to produce surface runoff and groundwater infiltration as a result. This represents input for the “horizontal water balance” module in which the groundwater flow is simulated by the system of discrete conduits representing known groundwater paths. In this study, the model is applied for simulation of the Dabarsko polje water balance in Bosnia and Herzegovina, as well as the river Bregava catchment runoff. The model is firstly calibrated based on recorded water levels in the Dabarsko polje and flow discharges at the Bregava spring. Obtained model is utilized to analyze the Dabarsko polje water balance and possible effects of the planned hydropower plant “Dabar”. Results indicate a high flow variation and necessity of integrated real-time water management of the whole Trebišnjica system

Estimation of the number of trays for natural gas triethylene glycol dehydration column

The paper deals with the tray-to-tray method for determining the required number of trays in columns with intensive entrainment of liquid when the operating line of the "dry working regime" is not straight and with a small concentration of diffusing component in gas. Presented calculations show that the number of transfer units for gas and liquid should be calculated using the AIChE method accompanied with longitudinal mixing according to Gilbert properly transformed for case of diffusion through stagnant film. The suggested method can be applied for TEG dehydration absorbers-columns for dehydration of natural gas using triethylene glycol with system factor SF = 0.5