Nanoparticle shapes: Quantification by elongation, convexity and circularity measures

The goal of the nanoparticle synthesis is, first of all, the production of nanoparticles that will be more similar in size and shape. This is very important for the possibility of studying and applying nanomaterials because of their characteristics that are very sensitive to size and shape such as, for example, magnetic properties. In this paper, we propose the shape analysis of the nanoparticles using three shape descriptors – elongation, convexity and circularity. Experimental results were obtained by using TEM images of hematite nanoparticles that were, first of all, subjected to segmentation in order to obtain isolated nanoparticles, and then the values of elongation, convexity and circularity were measured. Convexity C x ( S ) is regarded as the ratio between shape’s area and area of the its convex hull. The convexity measure defines the degree to which a shape differs from a convex shape while the circularity measure defines the degree to which a shape differs from an ideal circle. The range of convexity and circularity values is (0, 1], while the range of elongation values is [1, ∞). The circle has lowest elongation (ε = 1), while it has biggest convexity and circularity values ( C x = 1; C = 1). The measures ε( S ), C x ( S ), C ( S ) proposed and used in the experiment have the few desirable properties and give intuitively expected results. None of the measures is good enough to describe all the shapes, and therefore it is suggested to use a variety of measures so that the shapes can be described better and then classify and control during the synthesis process

Analysis of radionuclides content in soil samples from area of Aleksandrovačka Župa, Serbia

Naturally occurring radionuclide (uranium, actinium and thorium series and 40K) are widespread in the environment. In addition, significant amount of 137Cs may also be present in the soil as a result of accidents, such as Chernobyl accident. Thus, monitoring of radionuclides content in soil is of great importance. Aleksandrovac is small town in the western part of central Serbia and Župa is identified as the administrative territory of Aleksandrovac municipality. Nature of Aleksandrovačka Župa is under the long-lasting influence of anthropogenic factors, and therefore dominates altered natural landscape. Activity concentration of 226Ra, 232Th, 40K and 137Cs in 26 soil samples collected from different location in the territory of Aleksandrovačka Župa were determined and presented. All soil samples were milled and sealed in 0.5 l Marinelli beakers, and stored for six weeks in order to reach radioactive equilibrium between 226Ra and its descendants. All samples were measured by means of coaxial semiconductor HPGe detector (ORTEC GEM-30, 37% relative efficiency and 1.8 keV resolution for 60Co at 1332 keV line). The detector was calibrated using the standards in the same geometry spiked with common mixture of gamma-ray emitters certified by Czech Metrological Institute. The activity concentrations of radionuclides 40K and 137Cs in soil samples were determined directly by analyzing full-energy peaks of their principal energies at 1460.83 keV and 661.66 keV, respectively. The activity of 40K was corrected for the contribution of 228Ac (1459.14 keV). The activity of 226Ra was determined by analyzing full-energy peak at 186.21 keV, corrected for the contribution of 235U (185.72 keV) evaluated via 235U photo-peak at 143.77 keV and additionally approved by analyzing activity concentrations of its descendants (214Bi and 214Pb). Furthermore, the activity concentration of 232Th was determined by using the evaluated activity of its descendants (228Ac, 212Bi, 212Pb, and 208Tl). All obtained activity concentrations were corrected for the coincidence summing effect, applying the calculation method of Debertin and Schötzig (1990).Third International Conferenceon Radiation and Applications in Various Fields of Research, RAD 2015, June8-12, 2015, Budva, Montenegr

Mathematical Modeling of Environmental Impacts of a Reactor Through the Air

This paper presents an algorithm for the calculation of internal and external doses as an integral part of the mathematical model of atmospheric dispersion. The air pollution dispersion model is used on average annual activity concentration in the air, deposition on soil and field of total annual dose to a hypothetical resident contaminated by air in the vicinity of a nuclear reactor. The results of modeling were compared with values from an IAEA publication for a given scenario of radionuclide emission to the atmospheric boundary layer. Due to small differences in the results, compared to the IAEA recommended model, the model presented in the paper can be used as a basis for this type of analysis

One numerical method for determining the absorbed dose of gamma and X radiation in the ZrO2 dielectric within the MOS capacitor

At present, advanced microelectronics devices with Metal-Oxide-Silicon (MOS) structures are used to improve the functional characteristics of devices used in nuclear technology, radiation dosimetry and radiation protection in aerospace engineering, nuclear industry and radiotherapy equipment. Among other things, it is often the goal of new research to find new materials for the dielectric oxide such as of zirconium oxide (ZrO2) with higher dielectric constant (high-k) and testing its characteristics in an environment with radioactive radiation. The paper presents the application of a numerical method for the determination of the absorbed dose of gamma and X radiation in the dielectric thin layer of zirconium oxide, which is located in the structure of the MOS capacitor. The relation on the basis of the numerically calculated absorbed dose of radiation is obtained by using the theory of the physical transport of photons in a thin layer of dielectric. In doing so, it is necessary to know the spatial dependence of the photon flux of gamma or X-ray in a volume of the dielectric, as well as the values of the total mass attenuation coefficient and total energy absorbed mass coefficient for ZrO2 as a radiation characteristic of the material from which is made a dielectric. Based on the results of our research, it can be concluded that ZrO2 has satisfactory radiation characteristics as an alternative to the selection of dielectrics in MOS structures that are incorporated in dosimeters and radiation monitors.VII International Conference on Radiation in Various Fields of Research : RAD 2019 : book of abstracts; June 10-14, 2019; Herceg Novi, Montenegr

Radon exhalation rate of some building materials common in Serbia

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.Conference of 6th International Conference on Radiation and Applications in Various Fields of Research, RAD 2018 ; Conference Date: 18 June 2018 Through 22 June 2018; Conference Code:14955

Overview of Radiation Effects on Emerging Non-Volatile Memory Technologies

In this paper we give an overview of radiation effects in emergent, non-volatile memory technologies. Investigations into radiation hardness of resistive random access memory, ferroelectric random access memory, magneto-resistive random access memory, and phase change memory are presented in cases where these memory devices were subjected to different types of radiation. The obtained results proved high radiation tolerance of studied devices making them good candidates for application in radiation-intensive environments

Leaching kinetics of Cs+ and Co2+ under dynamic conditions

The possibility of retaining Cs+ and Co2+ bound by immobilization processes in the cement matrix is defined as the subject of its investigation: the cement matrix formulation, the water/ cement ratio, the amount of waste, and the porosity of such a structure. Implementing the standard leaching method by Hespe the possibility of comparing different authors’ results was achieved. Diffusion and semi-empirical model were used to investigate the transport phenomenon in order to predict the leaching level for a long period of time. Leaching of Co2+ and Cs+ ions under dynamic conditions immobilized in the cement matrix dynamic conditions decreases with the increase of the sludge content, regarding porosity increase. The effects of the diffusion and surface washing are equalized, and the contribution ofthe matrix dissolution to the Cs + and Co2+ transport in the cement porous media increases, on average, for one order of magnitude. The semi-empirical model gives a better approximation for Co2+ and Cs+ leaching process for the duration ofthe experiment while both models significantly approximate leaching results in dynamic conditions. © 2019, Vinca Inst Nuclear Sci. All rights reserved

Merits and demerits of different methods for radon exhalation measurements for building materials

With an increase in the awareness of the need to save energy, residents tend to live in dwellings with increasingly tight windows and doors, thus reducing the ventilation rate of indoor air which leads to an increased accumulation of radon indoors. Having in mind that a dose from an exposure to inhaled radon and its progenies can be higher than a dose received from radium in building materials, it is suggested that radon exhalation measurements should receive due attention. In this contribution, the authors compare results gathered using a few methods for radon exhalation measurement and discuss its merits and demerits

Selected methods for buildup factor calculation in gamma and X radiation protection

U ovom radu je dat pregled izabranih metoda proračuna buildup faktora na osnovu empirijskih aproksimacija Bergera, Tejlora i aproksimacije Geometrijske Progresije, sa kojima mogu da se rešavaju praktični problemi u zaštiti od zračenja u zavisnosti od stepena njihove složenosti. Razmatran je bazičan slučaj za određivanje buildup faktora u zavisnosti od karakteristika homogene materijalne sredine kroz koju se obavlja transport fotona X i gama zračenja, zatim od energije fotona iz izvora zračenja, kao od rastojanja između izvora fotona i tačke u materijalnoj sredini u kojoj se određuje dozimetrijska veličina. Posle sprovedene diskusije rezultata proračuna buildup faktora za olovo, gvožđe, običan beton i vodu, u radu su izvedeni odgovarajući zaključci u vezi efikasnosti primene pojedinih metoda proračuna u homogenoj materijalnoj sredini, uzimajući u obzir da svaka od prikazanih metoda ima svoje prednosti, kao i ograničenja, u zavisnosti od fokusa njene primene.This paper provides an overview of selected calculation method buildup factors based on empirical approximation that can not be solved practical problems in radiation protection, depending on their level of complexity. A basic case was considered for the determination of the buildup factor depending on the characteristics of the homogeneous material environment through which the transport of photons X and gamma radiation is carried out, then from the energy of photons from the radiation source, from the distance between the photon source and the point in the material environment in which the dosimetric size. After the discussion of the results of the calculation of the buildup factors for lead, iron, ordinary concrete and water, the conclusions about the efficiency of the application of individual calculation methods in a homogeneous material environment were carried out, taking into account that each of the methods presented has its advantages, as well as the limitations, depending on the focus of its application.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Selected methods for buildup factor calculation in gamma and X radiation protection

U ovom radu je dat pregled izabranih metoda proračuna buildup faktora na osnovu empirijskih aproksimacija Bergera, Tejlora i aproksimacije Geometrijske Progresije, sa kojima mogu da se rešavaju praktični problemi u zaštiti od zračenja u zavisnosti od stepena njihove složenosti. Razmatran je bazičan slučaj za određivanje buildup faktora u zavisnosti od karakteristika homogene materijalne sredine kroz koju se obavlja transport fotona X i gama zračenja, zatim od energije fotona iz izvora zračenja, kao od rastojanja između izvora fotona i tačke u materijalnoj sredini u kojoj se određuje dozimetrijska veličina. Posle sprovedene diskusije rezultata proračuna buildup faktora za olovo, gvožđe, običan beton i vodu, u radu su izvedeni odgovarajući zaključci u vezi efikasnosti primene pojedinih metoda proračuna u homogenoj materijalnoj sredini, uzimajući u obzir da svaka od prikazanih metoda ima svoje prednosti, kao i ograničenja, u zavisnosti od fokusa njene primene.This paper provides an overview of selected calculation method buildup factors based on empirical approximation that can not be solved practical problems in radiation protection, depending on their level of complexity. A basic case was considered for the determination of the buildup factor depending on the characteristics of the homogeneous material environment through which the transport of photons X and gamma radiation is carried out, then from the energy of photons from the radiation source, from the distance between the photon source and the point in the material environment in which the dosimetric size. After the discussion of the results of the calculation of the buildup factors for lead, iron, ordinary concrete and water, the conclusions about the efficiency of the application of individual calculation methods in a homogeneous material environment were carried out, taking into account that each of the methods presented has its advantages, as well as the limitations, depending on the focus of its application.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј