bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical and photoelectric properties of MoN/p-CdTe and MoN/n-CdTe heterojunctions
Authors: Kovaliuk T. T. , Solovan M. N. , Maryanchuk P. D.
Published: April 2021

Due to the physical properties of MoN and ITO thin films, it was decided to create MoN/p-CdTe and MoN/n-CdTe heterostructures and investigate their electrical and photoelectric properties. The method of reactive magnetron sputtering was used to create thin MoN and ITO films on single crystal CdTe substrates with different conductivity types. To manufacture test heterostructures, the following CdTe crystal substrates were used: 1) p-type conductivity, grown by Bridgman technique at low cadmium vapor pressures; 2) n-type conductivity, grown by Bridgman technique at high cadmium vapor pressures. During the deposition process, the argon pressure in the vacuum chamber was 0.4 Pa. The power of the magnetron was 30 W, the sputtering process continued 5 min at a substrate temperature of 150°C. I-V characteristics of the heterostructures at different temperatures were measured, the height of the potential barrier, the values of the series and shunt resistance were determined.
Electrical and photoelectric properties of the heterostructures were studied, and the dominant mechanisms of current transfer at forward displacements was established. The tunnel-recombination mechanism was found to be the dominant mechanism of current transfer in the MoN/p-CdTe and MoN/n-CdTe heterostructures.
It was shown that the photoelectric parameters for the MoN/p-CdTe heterostructure are higher than those for MoN/n-CdTe. MoN/p-CdTe heterojunctions have the following photoelectric parameters: open-circuit voltage Voc = 0.4 V, short-circuit current Isc = 24.6 mA/cm2 at an illumination intensity of 80 mW/cm2. This makes them a promising material for the manufacture of detectors of various radiation types.
Evaluating Algorithmic Risk Assessment
Authors: Hamilton Melissa
Published: April 2021

Algorithmic risk assessment is hailed as offering criminal justice officials a science-led system to triage offender populations to better manage low- versus high-risk individuals. Risk algorithms have reached the pretrial world as a best practices method to aid in reforms to reduce reliance upon money bail and to moderate pretrial detention’s material contribution to mass incarceration. Still, these promises are elusive if algorithmic tools are unable to achieve sufficient accurate rates in predicting criminal justice failure. This article presents an empirical study of the most popular pretrial risk tool used in the United States. Developers promote the Public Safety Assessment (PSA) as a national tool. Little information is known about the PSA’s developmental methodologies or performance statistics. The dearth of intelligence is alarming as the tool is being used in high-stakes decisions as to whether to detain individuals who have not yet been convicted of any crime. This study uncovers evidence of performance accuracy using a variety of validity metrics and, as a novel contribution, investigates the use of the tool in three diverse jurisdictions to evaluate how well the tool generalizes in real-world settings. Policy implications of the findings may be enlightening to officials, practitioners, and other stakeholders interested in pretrial justice as well as in the use of algorithmic risk across criminal justice decision points.
The performance of the Pamong Belajar in the Learning Activity Center: In the Perspective of Leadership, Organizational Culture and Achievement Motivation
Authors: Paus Julduz Ruland , Lumapow Harol R. , Senduk Johanis F. , Aditama Mint Husen Raya
Published: April 2021

The activities and existence of SKB as an educational institution in non-formal education units are a manifestation of the achievement of good corporate governance. This study aims to describe, predict and interpret the influence of leadership, organizational culture and achievement motivation on the performance of the Pamong Belajar at the Learning Activity Center (SKB) in North Sulawesi Province. The research approach used is quantitative with survey methods, while the hypothesis testing technique used is path analysis. There were at least 100 civil servants studying at 10 SKB and 15 districts / cities in North Sulawesi Province who were involved in this research. Research success indicators are measured based on 8 criteria contained in the Program Implementation Success Indicators (IKPP) and Institutional Success Indicators (IKK). From the results of the research analysis, it is found that the leadership characteristics of Pamong Belajar have a direct impact on organizational culture, achievement motivation and the performance of the Pamong Belajar SKB in North Sulawesi Province. However, there are interesting findings where achievement motivation can be a strong factor in the performance of the SKB Student Learning Association.
Effects of Web-Based Learning and Cultural Literacy Towards Non-formal Educator Performance
Authors: Djibu Rusdin , Duludu Ummyssalam
Published: April 2021

The purpose of this research is to find out: (1) the influence of Web-based learning with the performance of Educators, (2) the influence of cultural literacy with Educators' performance (3) the influence of Web-based learning and literary culture together with performance Educators. The method used in this study was with a quantitative approach with the ex-post-facto method. The population in this study was all non-formal educators working in the Gorontalo City learning activities workshop amounting to 107 people, while samples were 59 people using proportional random sampling. Data is collected through poll deployments. The conclusion to this research is (1) there is a positive influence on Web-based learning on educators' performance, which means that the better web-based learning is better for educator performance. (2) there is a positive influence on the cultural literacy of the educator's performance, meaning that both the literate culture is also the higher the performance of educators. (3) there is a positive influence on web-based learning and cultural literacy together to the performance of educators working in the Learning Activities workshop in Gorontalo city, this means that the higher the implementation of Web-based learning and culture of literacy, the higher the performance of non-formal educators.
Educational Equity: The Call of Global Education
Authors: Pellegrini Marta , Dell’Anna Silvia
Published: April 2021

As an indivisible sub-system of society, education is relatively independent and deeply restricted by the social environment. The issue of education equity is regarded as an extension and expansion of social equity in education. It is a vital link that cannot be ignored in education and an essential cornerstone of social justice.
The Relationship between Basic Education and Higher Education in a Pandemic Context: The Portuguese Situation
Authors: Serpa Sandro , José Sá Maria
Published: April 2021

In this article, the authors analyze the current situation in Portugal, in terms of the relationship between basic education and higher education, focusing on the influence of the COVID-19 pandemic in these processes. Moreover, this piece also addresses the quality of student preparation in basic education for a positive and successful experience in higher education.
Water quality control for the Argonauta reactor in Rio de Janeiro
Authors: Carvalheira Luciana , Ramos Leticia Lins , Nunes Rogerio Chaffin , Domingues Alessandro Mariano , Ferreira Francisco Jose de Oliveira
Published: April 2021

Different parameters should be monitored at a nuclear facility. Among them, water used in a nuclear reactor must meet strict specifications. The research reactor Argonauta, located in Rio de Janeiro, uses light water as both moderator and coolant. Quality control is the set of measurements to ensure, at any time, products that meet the parameters and standards in force. Then, the quality control of Argonauta’s water encompasses physical-chemical and radiological tests that are performed periodically to monitor deviations in the water parameters specification. These tests include the measurement of pH, conductivity, and gamma spectroscopy. By means of these tests, it is possible to evaluate if the quality parameters of this water meet the requirements defined by the reactor manufacturer and the Radiation Protection standards.  In this way, the safe operation of the Argonauta is guaranteed, besides avoiding unwanted exposures of operators and the environment to the ionizing radiation. This work presents the detailed assays performed in the water quality control. In addition, the obtained results in the last year measurements and highlights of the improvements to be done are also addressed. Moreover, a comparison among other research reactors in Brazil concerning this monitoring is presented. The obtained results indicate that pH, conductivity, and radiological parameters meet the established limits.
Immobilization of Liquid Radioactive Waste In Cement
Authors: Santana França Andreza Augusta
Published: April 2021

Immobilization of radioactive waste is required to comply with nuclear regulations and waste acceptance criteria in a repository, which require the waste to be solid or immobilized in solid form within a durable and resistant matrix .  Cement is the most frequently used material for the immobilization of liquid, low-level waste, since it has many advantages, such as the ease of preparation at room temperature and the low cost. In this paper, we describe the characteristics of cement-water mixtures, homogenized in a drum using a vibration table as the mixing device. Common Portland cement was used as the immobilization matrix. The homogeneity of the mixtures is evaluated using cement dye in appropriate amounts. Initially, the distribution of the mineral dye was made by visual inspection.  The batches were carried out with three different ways of feeding the components.  Different results were obtained depending on the feeding methods employed.
Toxicity and color reduction of reactive dyestuff RB21 and surfactant submitted to electron beam irradiation
Authors: Melo Camila Gomes , Rosa Jorge Marcos , Garcia Vanessa Silva Granadeiro , Borrely Sueli Ivone , Pereira Maria Conceição Costa
Published: April 2021

There is an unwelcome reaction between the coloring and the water during the dyeing procedure, a portion of the coloring agent is lost in the bathing and it will compose the final whole effluent. The high absorbance index is related to lost dyes and they also contribute with the toxic effects to the aquatic biota. In addition, these effluents contain large quantity of surfactants applied during dyeing baths, which also contribute to the high toxicity in these samples. The objective of this study was to evaluate electron beam irradiation technology, applied in samples of the Color Index Reactive Blue 21 (RB21) dye and in samples of surfactant nonionic and in order to reduce toxicity for both and for RB21, color reduction.  Among the objectives of the study there are the dye exhaustion degree, and some physic-chemical parameters. The acute toxicity assays were carried with Daphnia similis microcrustacean and the results for of dyestuff solution were: the irradiated samples with concentration of 0.61g.L-1 did not present significant results, the EC 50(%) value was to 58.26 for irradiated sample with 2.5kGy and EC 50(%) 63.59 for sample irradiated with 5kGy. The surfactant was more toxic than RB 21, with EC 50(%) value at 0.42. The color reduction reached 63.30% for the sample of the lowest concentration of effluent. There was a reduction of pH during irradiation.
Dosimetric tests of an extrapolation chamber in standard computed tomography beams
Authors: Castro Maysa Costa , Silva Natália Fiorini da , Caldas Linda Viola Ehlin
Published: April 2021

Computed tomography (CT) diagnostic exams are responsible for the highest dose values to the patients. Therefore, the radiation doses in this procedure must be accurate. For the dosimetry of CT beams, the radiation detector is usually a pencil-type ionization chamber. This type of dosimeter presents a uniform response to the incident radiation beam from all angles, which makes it suitable for such equipment since the X-ray tube executes a circular movement around the table during irradiation. However, there is no primary standard system for this kind of radiation beam yet. In order to search for a CT primary standard, an extrapolation chamber built at the Calibration Laboratory (LCI) of the Instituto de Pesquisas Energéticas e Nucleares (IPEN) was tested. An extrapolation chamber is a parallel-plate ionization chamber that allows the variation of its sensitive air volume. This chamber was used previously for low-energy radiation beams and showed results within the international recommended limits. The aim of this work is to perform some characterization tests (saturation curve, polarity effect, ion collection efficiency and linearity of response) considering the chamber depth of 1.25 mm in the radiation qualities for computed tomography beams at the LCI. The results showed to be within the international recommended limits.
Analysis of the swelling kinetic in hydrogels gelled by radiation and by thermal cycling
Authors: Bustamante Paola Andrea , Anessi Maria Carolina , Santoro Natalia Carolina , Ciavaro Nazarena , Horak Celina
Published: April 2021

Hydrogels are cross-linked polymer networks, which are of interest in biomedical applications such as drug delivery system. To achieve successful results in this kind of application it is essential to understand the diffusion mechanisms which are generated in the hydrogel during the swelling process. For this reason, this work consists in carrying out an analysis of the swelling kinetics in hydrogels elaborated through gamma radiation and the combination of gamma radiation with thermal cycling processes. The hydrogels were synthesized using biocompatible polymers irradiating their solution at different doses. A swelling test was performed and the diffusion coefficient and the diffusional exponent were calculated, making an analysis of the kind of diffusion mechanism in the hydrogel matrix. This test showed that the higher radiation absorbed used to get the gels, the lower the swelling percentage, as well as the diffusion coefficient of the water molecules in the hydrogel. The results of the kinetic analysis showed an anomalous diffusion mechanism for the gels obtained at 25 kGy. For those gels of 30 kGy, the diffusion was Fickian. Finally since those gels of 35 kGy was not possible to classify it according to the Fick's law of diffusion. Furthermore, we could observe that the hydrogels that had been obtained by thermal cycling and by irradiation had higher swelling percentages compared to those that were only cross-linked by irradiation. This analysis allowed us to understand the intrinsic behavior of the polymer / solvent mesh system at different doses and under two different crosslinking conditions.
An analysis of the support and quality of live after the diagnosis and treatment of prostate cancer in the radiotherapy sector
Authors: Ferreira Dickson Cardoso
Published: April 2021

Prostate cancer is the most common chronic disease among men in most parts of the world. According to the National Cancer Institute (INCA) in Brazil in 2018, 68,000 new cases were registered. Among the main treatments the radiotherapy has been shown to be effective in controlling and curing the disease. However, it is noted that the patient satisfaction index is not the most encouraging and there is little research that points to the sup-port of the hospital team. The aim of this study was to collect data from medical records about the adverse effect of the disease and through questionnaire the level of knowledge about the disease and the support offered by sector and to make recommendations for radiotherapy units Data were collected from 147 patients and of that total, 51 answered the questionnaire. The survey also shows that there was little referral to the complementary therapeutic service during of treatment. It is identified that more than 50% them knew very little about prostate cancer and 42% had no participation in the choice of treatment. It is observed that it is difficult to insert support policies for patients with prostate cancer, the professionals who work in oncology and radiotherapy centers underestimate the effects of the disease. It is observed, through research, that many of the symptoms and debilitations could be mitigated if there was a greater interaction between the health team and the patient, reducing the effects of radiation and accelerating the patient's integration for the social environment.
Comparison of geopolymer and cement as solidification matrixes for radwaste oil treated with bentonite
Authors: Freire Carolina Braccini
Published: April 2021

Lubricating oils in nuclear power plants may contaminate with radionuclides and become a challenging radwaste for treatment because they decompose in storage and disposal. In addition, conventional methods of immobilization in cement should be checked. This work intends to compare cement and geopolymer used to solidify lubricating oil previously decontaminate using bentonite as sorbent material. Cement is a well-known matrix for radwaste immobilization and geopolymer (alkali-activated material) has been proposed as a new immobilization technology, due to its advantages comparing to cement and bitumen. The geopolymers are cementitious binders formed by aluminosilicates activated in alkaline medium. Synthesis occurs by means of polymerization or polycondensation reactions from the dissolution of SiO44- and AlO45- ions of the aluminosilicates in a highly alkaline solution. After the treatment of the oil radwaste, the contaminated bentonite was immobilized in geopolymer and cement matrix and the final immobilized waste properties were evaluated: compressive strength and homogeneity. The compressive strength result in cement matrix specimens (13,38 MPa) has been higher than in geopolymer matrix (5,96 MPa). Nevertheless, when the homogeneity was compared, the resultant waste in geopolymer presented an aspect more homogeneous than the in the cement matrix. The results showed that the contaminated bentonite was not distributed homogeneously in cement matrix, for this reason the cement was not adequate to solidify the simulated waste. The compressive strength result for the waste in geopolymer matrix did not meet the Brazilian waste acceptance criteria. Therefore, new compositions of geopolymer matrix using less water will be carried out to improve the compressive strength and reach the recommended by Brazilian legislations.
Analysis of the pigments in two modern Egyptian papyri using XRF technique
Authors: Nardes Raysa Costa
Published: April 2021

In this work, two modern Egyptian papyrus belonging to a private collection were analyzed using X-Ray Fluorescence technique (XRF). The papyri are genuine, made from the papyrus plant, and hand-painted. The papyri were bought in the city of Cairo, Egypt, in the ‘80s and brought to Brazil in the same period. XRF analyses were performed using a portable spectrometer ARTTAX (X-ray tube with Mo anode and a Silicon Drift Detector XFlash®, Bruker AXS Inc.). XRF measurements were carried out under the following experimental conditions: 35 kV, 600 μA, unfiltered x-ray beam, air atmosphere, acquisition time of 600 s. The elements detected in the two papyri were: Si, Al, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba and Pb. Through the XRF analysis it was possible to evaluate the pigments found in the two papyri are different from each other. In the analysis of the blue color, present in the papyrus, it was observed that the composition of this color can be a mixture of two pigments: Egyptian blue (CaCuSi₄O₁₀) and Lithopone (ZnSBaSO4). Most of the pigments on the papyri were thus recognized to be modern, their syntheses, or refinement processes not being known to ancient Egyptians.
Estimated Pollutant Load from Nuclear and Energy Research Institute (IPEN/CNEN-SP, BRAZIL)
Authors: Silva Tatiane Bernardino de Seixas Carvalho da , Oliveira Cintia Carvalho de , Marques Joyce Rodrigues , Faustino Mainara Generoso , Stellato Thamiris Brandino , Monteiro Lucilena Rebelo , Pires Maria Aparecida Faustino , Cotrim Marycel Elena Barboza
Published: April 2021

To quantify the pollutant load received by a water body is one necessary step to keep its original standards, irrespective to the releasing source. Thus, to monitor and control the amount of pollutants released in a water body assures the water will remain free from excessive pollution. Also, that no harm to human health and the environment will occur. Hence, this paper aims to estimate the pollutant load of sanitary wastewater released by the Nuclear and Energy Research Institute (IPEN / CNEN-SP) in 2015 and 2016. The analysis of Cd, Pb, Cu, Cr, Zn, Ba, Ni, Mn, Fe, B and Sn was performed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). These metals and the total fixed solids were used to estimate the pollutant load. Wastewater flow measurement was carried out using bromide (Br -) as tracer and with the values from IPEN`s annual water consumption. Since 2006, this is performed as part of the Environmental Monitoring Program (PMA-Q). In compliance with the current Brazilian Environmental Legislation and with the Term of Conduct Adjustment requirements, agreed with the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA). Even the pollutants load has increased in 2015 and 2016, the monitoring frequency and water consumption has diminished in the last years. These facts increase the uncertainties in the monitoring and could lead to non-compliances with the monitoring laws.
A diffractometer project for Brazilian Multipurpose Reactor (RMB): McStas simulations and instrument optimization
Authors: Souza Alexandre Pinho dos Santos , De Oliveira Luiz Paulo , Yokaichiya Fabiano , Genezini Frederico Antonio , Franco Margareth Kazuyo Kobayashi Dias
Published: April 2021

High-resolution diffractometer is one of the first instruments of the set of 15 priority neutron scattering instruments to be installed at the Brazilian Multipurpose Reactor (RMB). A basic project of this instrument consists of the existence of three guides through which neutrons pass from source to sample to guarantee maximum neutron flux at the sample position. In this study, we investigate guide geometry performance considering fixed diffractometer geometry and spatial arrangement. Comparisons between different guide shapes and supermirrors are performed using software based on the Monte Carlo method, McStas. Our conclusion shows that a better solution is splitting the initial flux into two different guides to obtain the maximum flux at the sample position.
Application of semi-empirical model for the evaluation of radium activity in phosphogypsum used as component of clinker
Authors: Geraldo Ricardo Rossasi , Paschuk Sergei Anatolyevich , Barreto Rafael Carvalho , Corrêa Janine Nicolosi , Zahn Guilherme Soares , Cardoso da Silva Paulo Sergio , Malagi da Silva Amanda Claudia , Narloch Danielle Cristine , Araujo Isabelle Cabello
Published: April 2021

Phosphogypsum is a residue that has been used by the cement industry as a substitute for the natural gypsum, used as a clinker additive during the production of Portland cement. There is a potential increase in this residue use since the large amount of phosphogypsum is generated as outcome of the phosphate fertilizer industries. However, phosphogypsum can be considered a source of radioactive contamination since it has 226Ra in its composition. Depending on the concentration of 226Ra, from the radiological protection point of view, this may cause a problem because this radionuclide and its direct decay product 222Rn along with other decay products, represent the largest fraction of radiation internal dose received by people. In order to evaluate the level of radiological risk that may be associated with the use of phosphogypsum, it is necessary to identify the concentration of 226Ra in building material. The aim of this research is to analyze the samples of phosphogypsum in relation to the concentrations of 226Ra, determined indirectly through 222Rn activity measurements. This measurement process has the advantage of being fast, convenient and relatively inexpensive when compared to traditional 226Ra concentration in samples measurement methods. Proposed physical-mathematical model was used to establish radium concentration from radon exhalation rate from cement mortar samples. The 222Rn activity measurements were performed with a portable detector with cubic phosphate samples with 50 mm edges each placed in a closed atmosphere of the sampling chamber until secular equilibrium is achieved. Obtained concentrations of radium activity in studied samples of phosphogypsum and cement mortars were found below the limits recommended by CNEN and international regulation.
Drying and characterization of evaporator concentrates coming from PWR
Authors: Faria Érica Rodrigues de , Tello Clédola Cássia Oliveira de
Published: April 2021

In order to control the fission, boric acid is added to the water of primary circuit inside a Pressurized Water Reactor (PWR). After used, this solution is treated in evaporator to reduce its volume, generating the evaporator concentrate (EC). This concentrate should be solidify for transported and storage. Cementation is one of available process to incorporate the concentrate. However, when the evaporator concentrate is cemented there is an increase in the volume of the final product. It is proposed to use an additional process, drying prior be to the cementation. This process is applicable to further reduce the waste volume to be solidificated reducing the number of waste packages, consequently decreasing the storage area and all related risks. Two equipment, lab oven and spray dryer were studied to treat the evaporator concentrate. The dried EC was characterized, and the density, the particle size and the surface area were determined. After drying the evaporator concentrates solution, there was more than 80% weight reduction and initially, the dried product of the spray dryer showed better conditions to be incorporated in cementitious matrix.
In vivo genotoxicity of 2-alkylcyclobutanones in liver cells from rats fed with irradiated cocoa butter using flow citometry.
Authors: Martins Regiane , Perez Vieira Daniel , Ramirez de Carvalho Luma , Bueno Barbezan Angélica , Villavicencio Anna Lucia Casañas Haasis
Published: April 2021

Food irradiation proves to be an effective technique of eliminating some pathogens from food and this has gained significant attention to its potential for food safety. Since 1990, studies on the toxicological safety of 2-Alkylcyclobutanones have been conducted extensively. 2-Alkylcyclobutanones are unique radiolytic products generated by the radiation-induced breakage  of triglycerides in food, 2-dodecylcyclobutanone (2-dDCB) and 2-tetradecylcyclobutanone (2-tDCB) are the predominant compounds detected . Despite studies showing non-genotoxicity of 2-ACBs (2-Alkylcyclobutanones), the results are conflicting and therefore we continue the studies in order to confirm the compounds  are safety for human health. In vivo micronucleus test were performed to verify the 2-ACBs genotoxic effects in hepatic cells using flow citometry. We used cocoa butter irradiated with 20 kGy. A group with animals  was treated with daily intake of irradiated cocoa butter, synthesized 2-dDCB and 2-tDCB for one month. Hepatic cells were selected for genotoxicity analysis due to the liver importance in the compounds metabolization. The improvement of the analytical techniques is important for the research future since the irradiation process is already consolidated. The results confirmed the safety of the food irradiation process, as they did not indicate the genotoxic potential of the samples. Keywords: 2- Alkylcyclobutanones, Micronucleous test, liver.
Study of the relationship between mineralogical types and potential radon in rocks of the region of Serra do Gandarela – Quadrilátero Ferrífero-MG.
Authors: Taveira Natália Fonseca , Guimarães Frederico , Santos Talita , Rios Francisco , Franklin Mariza , Diniz Ariela , Neto Aimoré , Menezes Maria Ângela , Rocha Zildete
Published: April 2021

The Quadrilátero Ferrífero (QF) is one of the most well-known metallogenetic provinces in the world and has its geological context well studied since the end of the 17th century. The Serra do Gandarela is positioned in the northeast of the QF and is supported by units of the Minas Supergroup. The Moeda Formation (MF) in the Serra do Gandarela hosts an uranium (U) occurrence which was recently characterized in terms of mineralogical context. Uraninite, coffinite and brannerite are the main U minerals present. It is expected that mineralogy and lithology contribute to radon emanation and exhalation, the radon (Rn) transport from the soil to the atmosphere. In this work, the Rn exhalation was correlated to the lithological types. Samples from the MF conglomerates and Nova Lima group schists were collected from the Serra do Gandarela. Rn exhalation measurements were performed on the samples with AlphaGUARD detector. These values were compared to the U content of samples obtained via INAA. The result of INAA was more expressive in the MF conglomerate sample from the NUCLEBRÁS drillcore, with a U concentration value of 24 µg.g-1. The sample that had the highest average exhalation rate was also the same. The lowest value presented for both U concentration and average exhalation rate was shale, which were, 2 µg.g-1 and 180 Bq.m-3, respectively. The results are relevant for exploration and mining activities, during which Rn can accumulate in galleries. Additionally, the knowledge of the characteristic emanometric can be an important tool for geological and environmental studies.
Study on s-shaped guide using mcstas software
Authors: De Oliveira Luiz Paulo , Souza Alexandre Pinho dos Santos , Yokaichiya Fabiano , Genezini Frederico Antônio , Franco Margareth K.K.Dias
Published: April 2021

Monte Carlo simulations are performed for a vertical S-shaped neutron guide for the cold neutron sources of the FRM-II, HZB and PSI reactors through the McStas software. The aim of our study is investigate a relation between the cutoff in the cold neutron spectrum and the sources. Results for the neutron flux at the sample position are presented for different supermirrors with m = 1, 2 and 3. The vertical S-shaped neutron guides additionally provide a vertical displacement between beam hole and sample position, which can facilitate the implementation and manipulation of sample environments.
USE OF MONTE CARLO SIMULATIONS FOR OPTIMAL GEOMETRY STUDY IN CALCULATION OF ATTENUATION COEFFICIENT FOR ELEMENT, COMPOUND AND MIXTURE
Authors: Barbosa Caroline Mattos , Raitz Cesar , Dam Roos Sophia de Freitas , Salgado William Luna , Salgado Cesar Marques , Braz Delson
Published: April 2021

MCNP is a code extensively used to simulate experiments involving transport of radiation using the Monte Carlo method. This code allows the study of different geometries, materials, and radiation types (e.g. gamma, neutron, and electron), enabling the building of approximate models before the experimental implementation. The objective of this study is to develop an optimal geometry for the calculation of the mass attenuation coefficient for different materials using the MCNP code. Several measurement geometries were tested with different radiation energies, and the best results were obtained using lead collimators on both detector and radiation source. The considered geometries were isotropic source without any collimation, isotropic source with detector and/or source collimation, and a point source collimated into a cone of directions. The last case was proposed as a replacement for the computationally time expensive simulation of the two-collimator geometry. The energies 59.54 keV, 81 keV, 356 keV, and 662 keV were used to model 241Am, 133Ba, and 137Cs radiation sources, respectively. The materials were, NaI for the detector, aluminum, water, and sea water (3.5% NaCl) for the target sample, and lead for the collimators. The values of mass attenuation coefficient obtained from the simulations were compared with the theoretical NIST XCOM values for validation of the geometries.
Electron beam irradiation of combined pharmaceuticals: propranonol and fluoxetine and related ecotoxicity
Authors: Boiani Nathalia Fonseca , Granadeiro Vanessa Silva Garcia , Borrely Sueli Ivone
Published: April 2021

There are serious evidences that justify the search for treatment technologies or processes combination for the improvement of decomposition for dozens of pharmaceuticals in wastewaters. Electron beam irradiation may play an important role in this scenario and relatively low doses have been reported for such purposes. The aim of the present study was to evaluate the toxic response of the crustacean Daphnia similis exposed to individual and combined pharmaceuticals, before and after electron beam irradiation treatment. Several experimental trials of an acute immobilization test were performed with a mixture of pharmaceuticals composed of fluoxetine hydrochloride (Prozac®), and propranolol. Single pharmaceuticals were first tested separately. Toxicity of binary mixture was then assessed using five concentrations and five percentages of each substance in the mixture (0, 25, 50, 75, and 100%). Acute EC50% values ranged from 5.0 to 7.4 for fluoxetine and from 11.3 to 13.7 for propranolol. In mixture, values ranged from 6.4 to 9.8. Fluoxetine was more toxic than propranolol for D.similis. The different pharmaceuticals concentrations employed in a mixture showed no difference in toxicity values. When electron beam irradiation was applied, approximately 80% of acute effects were reduced at 5 kGy, and the mixture containing a higher percentage of fluoxetine, also showed a greater reduction of toxicity.
Development and characterization of CsI(Tl) crystal for use as a radiation detector
Authors: Suzart Karoline Feitoza , Mesquita Carlos Henrique , Pereira Maria Conceição Costa , Hamada Margarida Mizue , França Alexandre
Published: April 2021

Cesium iodide crystal activated with thallium (CsI(Tl)) is used as radiation sensor because of its favorable characteristics as scintillator, when excited by gamma radiation. This crystal has good mechanical strength and it is relatively little hygroscopic. In the present work, the CsI(Tl) crystal was grown in the Nuclear Energy Research Institute (IPEN/CNEN/SP) by Brigdman technique, in two different formats: (a) cylindric (∅ 20.1 mm x ­ 11.9 mm) and (b) parallelepiped ( c 12.3 mm x ­ 19.5 mm). The scintillator response was studied through five gamma radiation sources:  99mTc (140 keV), 137Cs (662 keV), 60Co (1173 keV, 1333 keV) and 22Na (511 keV, 1275keV). The crystals were coupled to a photomultiplier tube using 0.5 McStokes viscosity silicone grease as the optical interface. All electronics for signal measurements were developed at IPEN. Luminescence property of the CsI(Tl) crystal was excited by the radiation from a 99mTc source. The energy resolution of the crystalline detector was determined by the FWHM parameter, corresponding to the photopeak width at half of its height. Gamma radiation was spectrometry performed with the following sources: 99mTc, 241Ba, 137Cs, 60Co and 22Na.
Аналіз коректності задач механіки непружного деформування, що враховують вплив напруженого стану на процеси радіаційного розпухання і радіаційної повзучості матеріалу
Authors: Чирков О.Ю.
Published: April 2021

Розглядаються сучасні моделі радіаційного розпухання і радіаційної повзучості опроміненого матеріалу, в яких враховується пошкоджуюча доза і температура опромінення. Сформульовано визначальні рівняння поведінки матеріалу, що дозволяє описувати неізотермічні процеси непружного деформування з урахуванням радіаційних ефектів зміцнення, розпухання і повзучості. Аналіз властивостей визначальних рівнянь дав змогу сформулювати умови, за яких потужність дисипації та потужність, що розвивається додат- ковими напруженнями на додаткових деформаціях, не зменшуються під час довантаження за умов нейтронного опромінення. На основі одержаних енергетичних нерівностей, що узагальнюють постулат Друкера стосовно опроміненого матеріалу, встановлено умови, які забезпечують коректність рівнянь радіа ційної повзучості. Наведено апріорні оцінки гранично допустимої величини пошкоджуючої дози для аустенітної сталі 08Х18Н10Т за різних температур опромінення. У практиці розрахунків на міцність одержані оцінки можуть бути корисними на етапі постановки задачі для аналізу адекватності вихідних даних.
Спектральне підсилення сейсмічних коливань ґрунтами на території Києва
Authors: Кендзера О.В. , Семенова Ю.В.
Published: April 2021

Наведено результати моделювання реакції ґрунтів території Києва на сейсмічне навантаження під час

зем летрусів. Аналіз реакції ґрунту на сейсмічне навантаження спрямований на визначення впливу місцевих ґрунтових умов на підсилення сейсмічних коливань і, отже, оцінку спектрів реакції ґрунту для майбутніх цілей сейсмостійкого проєктування. У межах території Києва виділено відносно однорідні інженерно-геологічні ділянки (таксонометричні зони), на яких сейсмічний ефект може істотно відрізнятися. Для кожної таксонометричної зони розраховано інтегральні коефіцієнти спектрального підсилення сейсмічних коливань за рахунок впливу місцевих ґрунтових умов. Побудовано карту розподілу відхилення інтегрального коефіцієнта підсилення ґрунтами сейсмічних коливань від середнього значення для території Києва. Запропоновану карту можна використовувати для внесення поправок у разі застосування спектрального методу розрахунку на аварійне сполучення навантажень з урахуванням сейсмічного впливу для встановлення значення розрахункового відносного прискорення ґрунту досліджуваного будівельного майданчика.
Особливості геологічної будови ділянки посадки марсохода NASA Perseverance на Марсі за результатами частотно-резонансної обробки знімків з космічних апаратів
Authors: Якимчук М.А. , Корчагін І.М.
Published: April 2021

Наведено результати експериментальних досліджень на Марсі на локальній ділянці посадки марсохода NASA Perseverance, в районі кратера Jezero і на площі в північній частині планети. Дослідження рекогносцирувального характеру проведені із застосуванням методів частотно-резонансної обробки та інтерпретації знімків ділянок обстеження з космічних апаратів з метою вивчення особливостей їх геологічної будови. Інструментальні виміри показали, що ділянка посадки марсохода розташована в межах вулканічної структури, заповненої мергелями. На поверхні в зоні посадки виявлені уламки кременистих порід. У районі розташування кратера Jezero інструментальними вимірами встановлено (підтверджено) наявність у розрізі планети 8 типів вулканічних споруд, заповнених: 1) сіллю; 2) вапняками; 3) доломітами; 4) мергелями; 5) кременистими породами; 6) базальтами; 7) ультрамафічними породами; 8) кімберлітами. Обстежен- ням окремих площ планети підтверджений факт наявності в її складі лише 27 відомих на Землі хімічних елементів. До відсутніх на Марсі хімічних елементів належить також кисень. Відсутність кисню на Марсі свідчить про те, що на планеті немає води, а отже, і льоду в полярних областях. У районі північного полюса Марса виявлені крупні вулканічні структури, заповнені сіллю. Виявлені на Марсі численні вулканічні комп- лекси, заповнені породами різного складу, є важливими аргументами на користь вулканічної моделі фор- мування зовнішнього вигляду планети. Результати досліджень свідчать про принципову можливість ви- користання даних дистанційного зондування планет і супутників Сонячної системи (знімків з космічних апаратів, посадочних модулів і телескопів) для вивчення внутрішньої будови об’єктів обстеження і складу присутніх на них порід, мінералів і хімічних елементів. Частотно-резонансна технологія обробки супут- никових знімків і фотознімків може бути використана для детальних досліджень на планетах і супутни- ках Сонячної системи в рамках великих наукових проєктів їх вивчення. Апробована мобільна технологія може також знайти застосування під час вибору місць відбору зразків порід для марсохода.
Антиоксидантні властивості рослинних екстрактів — стабілізаторів біодизелю
Authors: Лагута І.В. , Ставинська О.М. , Кузема П.О. , Іванніков Р.В. , Аніщенко В.М. , Ліннік О.П.
Published: April 2021

З використанням двох різних процедур екстракції одержано вісім етанольних екстрактів із листя рослин Magnolia X soulangeana Soul.-Bod., Magnolia kobus та двох зразків Camellia japonica L. За допомогою високо- ефективної рідинної хроматографії, методу Фоліна—Чокальтеу і DPPH тесту вивчено склад та анти- оксидантні властивості одержаних екстрактів. Показано, що основними складовими екстрактів магнолій є глікозиди кверцетину та похідні оксикоричних кислот, тоді як у екстрактах камелій переважають катехі- ни і похідні оксибензойних кислот. Склад екстрактів залежить не тільки від виду рослини, а й від способу екстрагування; загалом, екстракти, одержані при температурі 60 °C та під дією ультразвуку, мають біль- ший вміст поліфенолів, ніж екстракти, отримані кип’ятінням рослинного матеріалу у 70 %-му етанолі при ~85 °C ; загальна кількість фенольних сполук у екстрактах змінювалась у діапазоні 50—150 мг/л. Виявлено, що, попри значну різницю у вмісті фенолів, всі екстракти мають дуже високу антиоксидантну актив- ність як у тесті Фоліна—Чокальтеу, так і в реакції з DPPH радикалами. Показано, що екстракти мають загальний фенольний індекс 1,5—7,5, а протягом 30 хв реакції сім з восьми екстрактів інгібують понад 50 % радикалів DPPH навіть після розведення у 10 разів. Екстракт камелії з найвищими антиоксидантними властивостями було протестовано як добавку до біодизелю, що має запобігти його окисненню під час збе- рігання. Стабільність біодизелю, одержаного з Camelina sativa (L.) Crantz, досліджували за прискореною процедурою при 43 °C протягом чотирьох тижнів, критерієм окиснення біопалива слугувало його кислотне число. Попередні результати показали, що екстракт камелії може бути ефективним антиоксидантним агентом — запобіжником окиснення біодизелю.
Синтез і будова складних фосфатів Na3,5MIІ 0,5Fe1,5(PO4)3 (MII — Mg, Ni), одержаних в умовах кристалізації багатокомпонентних розчин-розплавів
Authors: Струтинська Н.Ю. , Співак А.B. , Баумер В.М. , Слободяник М.С.
Published: April 2021

Досліджено формування складних фосфатів у системі Na2O—P2O5—Fe2O3—MIIO (MII — Co, Mg, Ni) в умо вах кристалізації багатокомпонентних розчин-розплавів у розрізах мольних співвідношень: Na/P = 1,3, Fe/P = 0,3, Fe/MII = 2, у температурному інтервалі 1000—650 °С та одержано монокристали Na3,5MIІ0,5Fe1,5(PO4)3 (MII — Mg, Co, Ni) розмірами до 5 мм. В ІЧ-спектрах синтезованих складних фосфатів Na3,5MIІ0,5Fe1,5(PO4)3 (MII — Mg, Co, Ni) коливальні моди в частотних діапазонах 900—1200 см–1 (суперпозиція симетричних і асиметричних валентних коливань РO4-тетраедрів) та 400—600 см–1 (відповідні деформаційні коливання) підтверджують присутність ортофосфатного типу аніона в їх складі. Розраховані параметри комірок синтезованих фосфатів (тригональна сингонія, просторова група R-3c) знаходяться в межах значень (а, b) = 8,68 ÷ 8,80 Å і c = 21,47 ÷ 21,58 Å та залежать від розмірів двовалентного металу. В основі кристалічних каркасів фосфатів Na3,5MIІ0,5Fe1,5(PO4)3 (MII — Mg, Co, Ni) є фрагмент [(MІІ/Fe)2 (PO4)3], побудований з двох змішаних (MІІ/Fe)O6-поліедрів і трьох PO4-тетраедрів, а катіони натрію частково заселяють два типи позицій, що розміщені в порожнинах каркаса. Присутність вакансій у катіонній підґратці складних фосфатів зі структурою типу NASICON у подальшому будуть впливати на іонпровідні властивості твердих електролітів.
МУРАЛИ ХАРКОВА: ПРОСТІР, ПАМ’ЯТЬ, ПОЛІТИКА
Authors: Любавський Роман
Published: April 2021

У статті проаналізовано мурали Харкова, що з’явилися у місті упродовж 2008–2020 рр. 24 арт-об’єкти розглянуто як медіатори історичної пам’яті, що ретранслюють різні наративи/дискурси: радянсько-ностальгійний, регіональний, національний; виявлено контекст їх створення, практики їх інструменталізації різними агентами історичної пам’яті.

Ініціатором появи муралів, що репрезентують радянсько-ностальгійний дискурс, є міська влада. Найбільше таких зображень з’явилося у місті у 2013 р., напередодні святкування Дня міста та відзначення 70-річчя визволення від німецької окупації. Очільники міста ініціювали проєкт «Гордость Харькова», у межах реалізації якого у місті було створено мурали із зображенням харків’ян, життя та творчість яких безпосередньо пов’язана із подіями «Великої Вітчизняної війни» (В. Гризодубова, Г. Жуков, К. Шульженко, П. Набойченко). Ці та інші зображення ілюструють радянсько-ностальгійний і регіональний виміри публічного простору міста. Вони найчастіше поєднуються між собою, латентно або прямо актуалізуючи фантомні болі «першої столиці». Такі зображення завжди персоніфіковані. Критерії вибору персоналії – уродженець та мешканець Харкова, відомий на загальносоюзному рівні (Л. Гурченко, І. Бугримова та ін.).

Від 2014 р. спостерігаємо появу в місті зображень загальнонаціональних символів, що можна інтерпретувати як спробу вписати Харків до національного наративу, продемонструвати перебування міста у core українського політичного проєкту. Такі мурали є персоніфікованими й абстрактно-символічними (Т. Шевченко, воїни-герої Крут, герб України, петриківський розпис, вишиванка (орнамент), лялька-мотанка та ін.). Ініціаторами створення цих муралів є міська влада і громада міста. Зазначимо, що національний наратив майже ніколи не поєднувався з регіональним. Утім, зафіксовано випадки, коли радянсько-ностальгійний, регіональний та національний дискурси проектувалися в одному зображенні. Приміром, є мурал, на якому зображено загиблих воїнів-афганців і воїнів, що загинули під час АТО. Це може свідчити про багатошаровість історичної пам’яті мешканців регіону.

Отже, аналіз муралів як медіаторів певного образу минулого у просторі Харкова засвідчив, що з 25 муралів, створених у 2008–2020 рр., які мають яскраво виражене ідеологічне забарвлення, 13 ретранслюють у просторі міста Харкова радянсько-ностальгійний наратив, 12 – регіональний, 10 – національний.
«У ПОШУКАХ РАСТРЕЛЛІ...» (РЕСТАВРАЦІЯ АНДРІЇВСЬКОЇ ЦЕРКВИ У 2009–2020 РР.)
Authors: Нетудихаткін Ігор
Published: April 2021

Наприкінці 2020 року київська Андріївська церква була відкрита після тривалої реставрації (2009-2020). Філософія реставраційних робіт цього десятиліття була підпорядкована ідеї «повернення Растреллі». Крім того, прослідковується певна «тяглість» - адже під час поперещньої масштабної реставрації 1979-88 років автентичний вигляд (за колекцією автентичних креслень Растреллі) було повернено екстер’єру храму (передусім куполам). Авторству Растреллі належить також проєкт внутрішнього опорядження Андріївської церкви. Тож усі роботи мали на меті повернути максимально автентичний вигляд храму. Їх виконували реставратори науково-реставраційної майстерні Національного заповідника «Софія Київська» і ТОВ «ЕКСТЕР’ЄР-БУДСЕРВІС» (генеральний підрядник). Неофіційно роботу було поділено на чотири блоки з промовистими назвами – «Метал», «Камінь», «Дерево» та «Живописне полотно».