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1.
In this study, combustion curves of twenty-five Turkish lignites were obtained through use of a differential thermal analyser. 20 mg lignite samples were heated at a constant rate of 10 deg·min?1 in a 40 cc/min flow of air up to 1073 K and held for 10 minutes at this constant temperature. The combustion curves of the samples are compared and discussed. 相似文献
2.
S. Sugihara Efrizal S. Osaki N. Momoshima Y. Maeda 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(2):419-422
Leaf and aerosol samples were monthly collected in Mt. Sefuri (Fukuoka Prefecture). Radioactivities of 7Be, 210Pb and 40K were determined with gamma-ray spectrometry. The concentrations of some elements in the leaf samples were determined by
neutron activation analysis. Similar seasonal variation of 7Be and 210Pb was observed between leaf and aerosol samples, high in spring and winter and low in summer. Correlation factors for trace
elements contained in the leaf show large variations. This indicates that the contribution of two sources (atmospheric deposition
and uptake from soil) is very variable. 相似文献
3.
N. A. Mel’nik E. P. Lokshin T. A. Sedneva 《Russian Journal of Applied Chemistry》2004,77(8):1219-1222
The distribution of natural nuclides and of the effective specific radioactivity in processing of the sphene concentrate was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 8, 2004, pp. 1237–1240.Original Russian Text Copyright © 2004 by Melnik, Lokshin, Sedneva. 相似文献
4.
A. P. Summerton 《Journal of Radioanalytical and Nuclear Chemistry》1992,161(2):421-428
A highly salt tolerant shrub, samphire (Halosarcia halocnemoides), found growing in the soild alkaline residues in an evaporation pond at a former uranium and monoazite treatment plant, has been analysed for natural radionuclides and rate earths. The data obtained have been copared with that for plants from the local natural environment. Vegetation-to-soil concentration ratios have been determined. The radionuclide concentration ratios for samples from the contaminated site are similar to those from the natural environment. Significant differences have been noted in the case of the rare earth elements with an apparent preferential incorporation of the light rare earth elements into the plant growing in the chemical residues. 相似文献
5.
P. N. Dimotakis H. Papaefthymiou A. Springer L. Geotz 《Journal of Radioanalytical and Nuclear Chemistry》1988,127(2):133-141
In continuation, of an early study of trace metal /TM/ccontent of Greek lignites and power plant ashes, taken to assess mobilization of TM in Greece by the operation of power plants, new data are presented. Both power plant sites in Greece, i. e. /a/ Northern /Ptolemais, Kardia/, and /b/ Southern /Megalopolis/ have been examined for trace metal content in ashes and in locally used lignites. Instrumental neutron activation analysis /INAA/ was used to determine the content of about 30 minor and major elements. The uranium content of southern Greek lignites was found again to be exceptionally high. The new data are correlated with those of our previous investigation. 相似文献
6.
Information about the sorption of radionuclides on natural materials used for cementation of liquid radioactive wastes (RAW) is important for predictions of migration rates of radionuclides in the products of fixation. Cementation process for conditioning liquid RAW uses, besides cement, materials which improve quality of products. In Czechoslovakia technology among these materials are clinoptilolite tuffit, mordenite tuff, tobermorite and fly ash. Liquid RAW issued from nuclear power plants contains the principal radionuclides60Co,134Cs and137Cs, therefore, a sorption study of these radionuclides was carried out. pH of liquid RAW was 12.5–13.7 and salt content ca. 200 g·dm–3. Results of sorption are given by distribution coefficients. The best results for cesium in those pH region and salt content had mordenite tuff DCs=100 dm3·kg–1 and the worst results had fly ash DCs=4.1 dm3·kg–1. The best results for cobalt in those solutions had tobermorite DCo=38 dm3·kg–1 and the worst results had fly ash DCo=6.9 dm3·kg–1. 相似文献
7.
Influence of the mineral matter content on the rate of heat release from Turkish lignites 总被引:1,自引:0,他引:1
In this study, combustion curves of twenty-five original and demineralized Turkish lignite samples were obtained through use of a differential thermal analyser. The lignite samples were demineralized by treatment with hydrochloric and hydrofluoric acids. Samples of 20 mg were heated up to 1074 K at a constant rate of 10 K min–1 in a 40 cm3 min–1 flow of dry air. The rates of heat release from the original and demineralized samples were compared and are discussed. 相似文献
8.
H. Faghihian D. Rahi M. Mostajaboddavati 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):711-717
In this study the concentration of natural radionuclides has been investigated in soil and water of Karun river by using a
high resolution (HPGe detector, n-type) γ-spectrometry. The concentrations range in water sample was 47.6 ± 5.6–130.8 ± 6.3,
0.0–23.4 ± 0.5 and 0–6.4 ± 2.0 Bq L−1 for 40K, 232Th and 226Ra respectively. For soil samples the concentration range of 275.7 ± 8.6–458.6 ± 6.8, 19.2 ± 5.35–41.1 ± 3.95 and 29.9 ± 1.53–50 ± 1.54 Bq kg−1 was obtained respectively for 40K, 232Th and 238U. 137Cs was also detected in some part of the region in soil samples. The mean concentration of 137Cs was 5.5 ± 0.6 Bq kg−1. The origin of this activity is unknown. The average absorbed dose rate in outdoor air at a height of 1 m above the ground
was found to be 54.3 ± 3.7 nGy h−1. The results of this study indicate that the area has standard background radiation level. 相似文献
9.
D. C. Breban N. Paunescu J. Moreno-Bermudez R. Margineanu 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(3):503-508
Radioactive concentrations of several artificial and natural radionuclides were determined in water and sediment samples collected
from various locations in the NW Black Sea in December 1999. For water samples, 90Sr and 137Cs activity concentrations were of approximately 11 mBq/l and 26.3-41.2 mBq/l, respectively. The concentration of tritium
ranged from 7 to 24 T.U. In sediment samples, maximum concentrations of 137Cs, 239+240Pu and 241Am were found of 128±6 Bq·kg-1, 1.8±0.1 Bq·kg-1 and 0.05±0.04 Bq·kg-1, respectively. For U and Th radionuclides, the concentrations ranged from 20-80 Bq·kg-1 and 30-50 Bq·kg-1, respectively. The results were consistent with those reported in earlier research for the Black Sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
St. N. Kalmykov Yu. A. Sapozhnikov I. P. Efimov J. A. Broadway L. D. Sapozhnikova 《Journal of Radioanalytical and Nuclear Chemistry》1998,229(1-2):95-97
Fourteen samples of wastes from algal plants were tested for possible analytical and/or technological use for90Sr and137Cs extraction from natural waters. Sorption experiments were carried out in static and dynanic conditions. It was noted that
the examined sorbents posses high affinity for Sr2+. The sorption capacity reached the value of 4.72·10−3 mole/g. Simple and express analytical procedures for90Sr determination were developed and tested in the Dnieper estuary region. 相似文献
11.
The natural background gamma (NBG) spectrum was accumulated inside the laboratory, with 102.88 cm3 Ge(Li) detector, to investigate bismuth natural radionuclides in the energy range of 500–1700 keV. The relative intensities of identified214Bi gamma lines were obtained from the spectrum. The results were in good agreement with that obtained from a source of a precise strength. Out of the 25 gamma lines of214Bi, 19 lines were established including 6 lines observed for the first time in the NBG spectrum. Most of the gamma lines of211Bi and212Bi were observed. Some of these lines are new. 相似文献
12.
13.
14.
Adam Khatir Sam A. A. ElGanawi M. M. O. Ahamed F. A. ElKhangi 《Journal of Radioanalytical and Nuclear Chemistry》1998,237(1-2):103-107
The distribution of some natural and anthropogenic radionuclides (226Ra,228Ra,210Po,40K,137Cs) in surface marine sediments from the harbours at Port Sudan and Sawakin on the Sudanese coast of the Red Sea has been
investigated using α-spectrometry and direct high-resolution γ-spectrometry. The prime ams were to assess the levels of radioactivity
and the influence of factors such as dredging and the organic matter content of the sediments on the distribution pattern
of the radionuclides. The results have been evaluated and the leves indicate the absence of any possible enhancement by anthropogenic
influx from the hinterland. The spatial distribution pattern is more heterogeneous in Sawakin harbour where some parts have
recently been dredged and the sludge is removed to maintain the required depth. The data also show an insignificant relationship
between the activity concentrations of all the radionuclides and the content of organic matter in the sediments. 相似文献
15.
Speciation of natural and antropogenic radionuclides in different sea sediment samples 总被引:1,自引:0,他引:1
D. Desideri M. A. Meli C. Roselli C. Testa S. Degetto 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(3):727-733
A sequential extraction method consisting of six operationally-defined fractions was used to determine the geochemical partitioning of natural (U, Th,) and antropogenic (Pu, Am, 137Cs) radionuclides in three sediment samples of different origin (Venice Lagoon, Adriatic Sea; Gaeta Gulf, Thyrrhenian Sea; IAEA-367, Enewetak Atoll, Central Pacific Ocean). Fe, Mn, Al, Ti, Ca, Sr, Pb, Ba, K were also determined in the different fractions to get more information about the chemical association of the single radionuclides. The experimental results were compared to those described in the literature for an IAEA-135 Sea Sediment collected in the Irish Sea in front of the Sellafield Plant (UK). 相似文献
16.
H. Cabáneková 《Journal of Radioanalytical and Nuclear Chemistry》1996,209(2):301-306
The building materials and products whose content of natural radionuclides are contributors to the radiation exposure of the population. In this study several types of building materials used for construction of living buildings in Slovakia were examined. The concentrations of natural radionuclides (226Ra,232Th and40K) were determined by -ray spectrometry with an HPGe detector. In the second part of the work, sixty samples of building products (panel), used for dwelling construction in several towns in Slovakia, were analysed. The concentration of natural radionuclides and the radium equivalent activity content in the inner-and outerside of the wall were estimated. The results were used for the calculation of the annual mean effective photon dose rates, by the model and calculation procedure of KRISIUK and KARPOV. 相似文献
17.
N. Drndarski N. Miljević D. Golobočanin 《Journal of Radioanalytical and Nuclear Chemistry》1996,214(2):95-102
The distribution of natural radionuclides,40K,226Ra, and232Th, in freshwater sediments and in coal-fired power-plant ash repositories has been tested for lognormality. Thereafter, lognormality for natural radionuclide concentration frequency distribution was accepted with a high probability. The lognormal natural radionuclide distribution in sediments and coal-ash indicated single population groups. The anthropogenic modifications of the natural radionuclide concentrations in the environment are indicated. The adsorbed dose rates, in mGy y–1, in air from gamma field of the natural radionuclides were calculated. 相似文献
18.
Manjulata Yadav Mukesh Rawat Anoop Dangwal Mukesh Prasad G. S. Gusain R. C. Ramola 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(2):869-873
Distribution of natural radionuclide gives significant parameter to assess the presence of gamma radioactivity and its radiological effect in our environment. Natural radionuclides are present in the form of 226Ra, 232Th and 40K in soil, rocks, water, air, and building materials. Distribution of natural radionuclides depends on the type of minerals present in the soil and rocks. For this purpose gamma spectrometer is used as tool for finding the concentration of these radionuclides. The activity concentration of naturally occurring radionuclides 226Ra, 232Th and 40K in these soil samples were found to vary from of 8 ± 1 Bq/kg to 50 ± 10 Bq/kg with an average 20 Bq/kg, 7 ± 1–88 ± 16 Bq/kg with an Average 26 Bq/kg and 115 ± 18–885 ± 132 Bq/kg with an average 329 Bq/kg, respectively. In this paper, we are presenting the radiological effect due to distribution of natural radionuclide present in soil of Garhwal Himalaya. 相似文献
19.
P. K. Shetty Y. Narayana K. M. Rajashekara 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):159-163
The present work investigated the activity concentrations of natural radionuclides 226Ra, 232Th and 40K in beach sand samples along coastal Kerala including high background radiation area. The activity of 232Th ranges from below detectable level to 23029.9 Bq kg−1 with a mean value of 2660.2 Bq kg−1 for 0–10 cm depth interval. For 10–20 cm depth, the 232Th activity ranged from below detectable to 4452.2 Bq kg−1 with a mean value of 815.5 Bq kg−1. The variation of 226Ra activity with depth is parallel with the 232Th activity distribution in beach sand. Its activity varied from below detectable to 5169.5 Bq kg−1 with a mean value 487.6 Bq kg−1 at 0–10 cm depth. For 10–20 cm depth interval, the 226Ra activity ranges from below detectable to 1823.6 Bq kg−1 with a mean value 296.0 Bq kg−1. Similarly the activity varies from below detectable to 1826.6 Bq kg−1 with a mean value of 211.0 Bq kg−1 for a depth interval of 20–30 cm. The activity of 40K at different depth is also discussed. Statistical analysis of radioactivity was also carried out. The results of these investigations are presented in this paper. 相似文献
20.
P. P. Povinec M. K. Pham J. Busto C. Cerna D. Degering Y. Hamajima K. Holý M. Hult M. Ješkovský M. Köhler A. Kováčik M. Laubenstein P. Loaiza F. Mamedov Ch. Marquet J. Mott M. Műllerová F. Perrot F. Piquemal J.-L. Reyss R. Saakyan H. Simgen B. Soulé J. Staníček I. Sýkora I. Štekl 《Journal of Radioanalytical and Nuclear Chemistry》2016,307(1):619-626