scholarly journals Thermoluminescent and X-ray diffraction methods in dating of ceramics from archaeological excavations of the Orikti monument (Almaty region)

2020 ◽  
pp. 4-10
Author(s):  
Askar Bakhadur ◽  
Nadezhda Aluker ◽  
Galymzhan Bekseitov ◽  
Yerbolat Ospanov ◽  
Bolat Uralbekov
Keyword(s):  
Dose Rate ◽  
Dose Range ◽  
Sampling Site ◽  
Absorbed Dose ◽  
Average Dose ◽  
Preparation Technique ◽  
X Ray Diffraction ◽  
Absorbed Dose Rate ◽  
X Ray ◽  
Ceramic Samples

In this work, the ages of archaeological ceramics were determined by the thermoluminescent method after X-ray diffraction analysis (XRD) of ceramic samples, which confirms that quartz is the main component phase of the products. This allowed to use the sample preparation technique without isolating the quartz phase from the ceramic sample. Silicon oxide based soil-equivalent thermoluminescent detectors were used to determine the annual absorbed dose rate at the sampling site. The average dose rate at sampling site was 0.62 ± 0.02 cGy/year. Calculation of the ceramics ages was carried out after checking the linearity of lightsums accumulation for samples in the dose range up to 2000 cGy. Based on the performed studies, the ages of the ceramic products were determined that do not contradict to archaeologists dating of these products. It is proposed to use the procedure for determining ceramic samples by the thermoluminescent method after their phase composition identification by XRD. In the case of the predominant mineral composition of quartz phase (the proportion of quartz is more than 60% of the total composition of ceramics), the measurements can be carried out without the quartz isolating; while presence of clay mineral fractions commensurate with quartz levels can lead to the separation of the quartz.

scholarly journals Activity of natural radionuclides and their contribution to the absorbed dose in the fish cubera snapper (lutjanus cyanopterus, cuvier, 1828) on the coast of Ceara, Brazil

2010 ◽  
Vol 58 (spe4) ◽  
pp. 25-32 ◽  
Author(s):  
Wagner de S. Pereira ◽  
Alphonse Kelecom ◽  
Delcy de A. Py Júnior
Keyword(s):  
Dose Rate ◽  
Standard Dose ◽  
Natural Radionuclides ◽  
Absorbed Dose ◽  
Threshold Value ◽  
Average Dose ◽  
Absorbed Dose Rate ◽  
Dose Rates ◽  
A Value ◽  
Lead 210

A methodology was developed for converting the activity concentration of radionuclides (Bq kg-1) into absorbed dose rate (Gy y-1), aiming an approach to environmental radioprotection based on the concept of standard dose limit. The model considers only the internal absorbed dose rate. This methodology was applied to the cubera snapper fish (Lutjanus cyanopterus, Cuvier, 1828) caught off the coast of Ceará. The natural radionuclides considered were uranium-238, radium-226, lead-210, thorium-232 and radium-228. The absorbed dose rates were calculated for individual radionuclides and the type of emitted radiation. The average dose rate due to these radionuclides was 5.36 µGy y-1, a value six orders of magnitude smaller than the threshold value of absorbed dose rate used in this study (3.65 10³ mGy y-1), and similar to that found in the literature for benthic fish. Ra-226 and U-238 contributed 67% and 22% of the absorbed dose rate, followed by Th-232 with 10%. Ra-228 and Pb-210, in turn, accounted for less than 1% of the absorbed dose rate. This distribution is somewhat different from that reported in the literature, where the Ra-226 accounts for 86% of the absorbed dose rate.

scholarly journals Study on dose rate distribution inside diagnostic X-ray room by using MCNP5 code

2013 ◽  
Vol 16 (4) ◽  
pp. 35-42
Author(s):  
Loan Thi Hong Truong ◽  
Thu Thi Cam Nguyen ◽  
Hien Thi Doan ◽  
Khanh Ai Tran ◽  
Dung Thi Thuy Vo ◽  
...  
Keyword(s):  
Dose Rate ◽  
Radiation Safety ◽  
Absorbed Dose ◽  
Absorbed Dose Rate ◽  
Rate Distribution ◽  
X Ray ◽  
Room Size ◽  
Exact Determination ◽  
Mcnp5 Code

In this paper, the scattering influence on image quality and radiation safety because of changing room size was studied. To estimate the radiation safety in X-ray room, the exact determination of dose rate distribution inside the room and absorbed dose rate for patient is the first task. The authors simulated the dose rate distribution inside diagnostic X-ray room at Nhi Dong hospital with using MCNP5 code. The dependence of dose rate distribution on various peak voltages of X-ray tube was also investigated in this study

Absorbed dose rate assessment for the Japanese cedar stand affected after the Fukushima NPP accident.

2021 ◽  
Author(s):  
Rena Mikailova ◽  
Yuichi Onda ◽  
Sergey Fesenko ◽  
Hiroaki Kato
Keyword(s):  
Dose Rate ◽  
Water Content ◽  
Forest Ecosystem ◽  
Forest Ecosystems ◽  
Absorbed Dose ◽  
Japanese Cedar ◽  
Average Dose ◽  
High Concentration ◽  
Absorbed Dose Rate ◽  
Dose Rates

<p>The nuclear disaster from the FNPP accident resulted in the major contamination of forest ecosystem of Eastern Japan. Forests are the most susceptible to ionizing radiation exposure, especially conifers due to their high radiosensitivity and pollutant interception abilities. A high concentration of radionuclides in forest ecosystems caused an increase in the dose rate. Japanese cedar belongs to Japan's endemic species; therefore, the current study was aimed at the absorbed dose rate assessment of the C. japonica forest stand in the Yamakiya district. To estimate the absorbed dose rates to the Japanese cedar trees, we used the <sup>134,137</sup>Cs concentrations in different forest ecosystems’ compartments. The calculations include data from 2011 to 2017. The dose rate assessments were performed at different heights of the forest ecosystem (canopy, trunk, understory). The average dose rates decreased from 40 µGy/day in 2011 to 13 µGy/day in 2017. The assessment results comply with the ambient dose rate measured from 2011 to 2015. The assessment showed that the water content in the litter and topsoil layers significantly influence the formation of the dose rate. Via the model, we simulated the dose rates for 20% and 80% of the litter water content. The results showed that the average measured dose rates lie within the estimated results. Due to the lack of data on litter and soil moisture during sampling, now we are trying to calculate the ground layers’ water content using the available information on precipitation rate.</p>

scholarly journals Physicochemical and radiological characterization of kaolin and its polymerization products

2018 ◽  
Vol 68 (330) ◽  
pp. e155
Author(s):  
M. Ivanović ◽  
Lj. Kljajević ◽  
M. Nenadović ◽  
N. Bundaleski ◽  
I. Vukanac ◽  
...  
Keyword(s):  
Dose Rate ◽  
Photoelectron Spectroscopy ◽  
Specific Activity ◽  
Physicochemical Characterization ◽  
Natural Radionuclide ◽  
Absorbed Dose ◽  
Raw Material ◽  
Absorbed Dose Rate ◽  
X Ray

The aim of this study was determination of physical-chemical and radiological characteristics of kaolin and products of alkali-activated thermally treated kaolin (geopolymer). Also, the objective of presented research was to investigate the possibility of kaolin application as a pigment or as a raw material for obtaining geopolymer materials as a relatively new ones in a building material industry. Physicochemical characterization of one set of samples was conducted using X-ray diffraction (XRD), Fourier transform infra - red (FTIR) and X-ray photoelectron spectroscopy (XPS). Activity concentration of naturally occurring radionuclides in kaolin, metakaolin and geopolymer were determined. The absorbed dose rate (D) and the annual effective dose rate (EDR), calculated in accordance with the UNSCEAR 2000 report, are also presented in this paper. Kaolin was heat-treated on 750oC and specific activity of natural radionuclide in metakaolin increased up to 1.6, while measured specific activities in geopolymer were the lowest.

scholarly journals Reconstruction of the absorbed dose of ionizing radiation for helophytes in the water bodies of the near emergency zone at the Chornobyl NPP

2020 ◽  
Vol 21 (4) ◽  
pp. 338-346
Author(s):  
V.V. Belyaev ◽  
◽  
O.M. Volkova ◽  
D.I. Gudkov ◽  
S.P. Pryshlyak
Keyword(s):  
Ionizing Radiation ◽  
Dose Rate ◽  
Absorbed Dose ◽  
Growing Season ◽  
Plant Roots ◽  
Average Dose ◽  
Exclusion Zone ◽  
Absorbed Dose Rate ◽  
Radionuclide Content ◽  
Biological Dose

Based on modeling the dynamics of the Chornobyl emission radionuclide content in the components of the most polluted reservoirs of the Chornobyl Exclusion Zone, the absorbed dose for helophytes was reconstructed. During the growing season of 1986, the absorbed dose of plants of Glyboke Lake was 78 Gy, Daleke Lake 39 Gy. The absorbed dose rate of plant roots was 2.4 times higher than that of aboveground organs. According to actual data, in the period 2016 - 2019 in the Glyboke Lake average dose of external and internal plant irradiation was about 7.5 mGy/year, and in the Daleke Lake 5.6 mGy/year. On abnormally contaminated sections of the Glyboke Lake, the external dose reaches 0.5 - 1.0 Gy/year. During the period 1986 - 2020, the maximum cumulative (biological) dose of helophytes of Glyboke Lake can be 190 Gy, Daleke Lake 80 - 85 Gy.

scholarly journals Alkali activation of different type of ash as a production of combustion process

2021 ◽  
pp. 6-6
Author(s):  
Milos Nenadovic ◽  
Claudio Ferone ◽  
Ljiljana Kljajevic ◽  
Miljana Mirkovic ◽  
Bratislav Todorovic ◽  
...  
Keyword(s):  
Fly Ash ◽  
Dose Rate ◽  
Combustion Process ◽  
Chemical Properties ◽  
Gamma Ray Spectrometry ◽  
Alkali Activation ◽  
X Ray Diffraction ◽  
Absorbed Dose Rate ◽  
X Ray ◽  
Lignite Fly Ash

Presented study deals with the final structure and radiological properties of different fly ash-based geopolymers. lignite fly-ash (lignite Kolubara - Serbia) and wood fly ash were obtained in combustion process together with commercial fly ash. Synthesis of the geopolymers was conducted by mixing fly ash, sodium silicate solution, NaOH and water. The samples were cured at 60?C for 48h after staying at room temperature in covering mold for 24 h. X - ray diffraction, Fourier transform infra - red and Scanning electron microscope measurements were conducted on the samples after 28 days of geopolymerization process. X-ray diffraction measurements of lignite fly ash samples show anhydrite as the main constituent, while wood fly ash samples consist of calcite, albite and gypsum minerals. Beside of determination of physical-chemical properties, the aim of this study was radiological characterization of lignite fly ash, wood fly ash and the obtained geopolymer products. Activity concentration of 40K and radionuclides from the 238U and 232Th decay series in ash samples and fly ash-based geopolymers were determined by means of gamma-ray spectrometry, and the absorbed dose rate rate (D) and the annual effective dose rate (E) were calculated in accordance with the UNSCEAR 2000 report.

HUMAN EXPOSURE TO BACKGROUND RADIATION IN ORTUM, KENYA

2019 ◽  
Vol 188 (1) ◽  
pp. 98-108
Author(s):  
F O Wanjala ◽  
N O Hashim ◽  
D Otwoma ◽  
C Nyambura ◽  
J Kebwaro ◽  
...  
Keyword(s):  
Dose Rate ◽  
Human Exposure ◽  
Activity Concentration ◽  
Background Radiation ◽  
Absorbed Dose ◽  
Threshold Values ◽  
Absorbed Dose Rate ◽  
The World ◽  
Average Activity ◽  
Terrestrial Radionuclides

Abstract The activity concentration of radionuclides 238U, 232Th and 40K in soil and the absorbed dose rate (ADRA) at 1 m above the ground in Ortum was determined. The activity concentration in soils ranged from 33 to 85, 20 to 67 and 148–1019 Bq kg–1, respectively with an average of 40 ± 1.43, 56 ± 1.46 and 425 ± 19.24 Bq kg–1, respectively. The activity concentration of 232Th and 238U was found to reduce with increasing depth while that of 40K increased with increasing depth. The average activity concentration in soil was higher than the world average values. The average ADRA in air at 1 m above the ground was found to be 112 ± 29.6 nGy h–1. The soil and rocks in Ortum are recommended for use because the activity concentration of the terrestrial radionuclides is lower than the recommended threshold values.

Effects of Different Sintering Temperature on the Microstructure and Piezoelectric Properties of Pb(Nb2/3Zn1/3)x(Zr52Ti48)1-XO3 Ceramics

2014 ◽  
Vol 1061-1062 ◽  
pp. 83-86
Author(s):  
Hong Wu ◽  
De Yi Zheng
Keyword(s):  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Electromechanical Coupling Coefficient ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceramic Samples ◽  
Xrd Patterns ◽  
The Relationship

In this paper, the effects of different sintering temperature on the microstructure and piezoelectric properties of Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3(PNZZT) ceramic samples were investigated. The Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 ceramics materials was prepared by a conventional mixed oxide method. In the period of the experiment, the relationship between crystallographic phase and microstructure were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM) respectively. The XRD patterns shows that all of the ceramic samples are with a tetragonal perovskite structure. Along with sintering temperature increased and the x is 0.03, the grain size gradually become big. Through this experiment, it has been found that when the x is 0.03 and sintered at 1130°C for 2 h, the grains grow well, the grain-boundary intersection of the sample combined well and the porosity of the ceramics decreased, an excellent comprehensive electrical properties of the Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 samples can be obtained. Its best electrical properties are as follows: dielectric constant (ε) is 1105, dielectric loss(tg) is 0.017, electromechanical coupling coefficient (Kp) is 0.287, piezoelectric constant(d33) is 150PC/N

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