WorldWideScience
1

Artificial radioactivity in Lough Foyle  

International Nuclear Information System (INIS)

The purpose of this study was to assess the extent to which the marine environment of Lough Foyle, situated on the north coast of Ireland, has been affected by artificial radioactivity released from Sellafield. Although traces of plutonium, americium and radiocaesium from Sellafield are detectable in Lough Foyle, the concentrations in various marine media are significantly lower than those found along the NE coast of Ireland and in the western Irish Sea. The minute quantities of artificial radioactivity found in Lough Foyle are of negligible radiological significance

2

Artificial radioactivity in Carlingford Lough  

International Nuclear Information System (INIS)

The principal objective of this study was to assess whether radioactivity concentrations in a wide range of environmental materials from the Lough were enhanced above general levels found elsewhere along the east and north-east coasts of Ireland. Other objectives included an examination of gamma dose rates in air over inter-tidal sediments throughout the Lough and an examination of coastal soils to determine the extent of sea-to-land transfer of plutonium and , by inference, americium

3

Artificial radioactivity in Carlingford Lough, Ireland  

International Nuclear Information System (INIS)

The routine discharges of low-level liquid waste from the British Nuclear Fuels reprocessing plant at Sellafield in Cumbria have resulted in enhanced concentrations of artificial radioactivity in the Irish marine environment, particularly along the north-east coast. During 1990 a detailed study of levels of artificial radioactivity in Carlingford, Lough, a sea Lough in which a significant number of commercial shellfish producers are located, was carried out. The aim of this study was to determine whether radioactivity concentrations in environmental materials from the Lough were enhanced above those found elsewhere along the north-east coast. The study concluded that concentrations in the Lough were broadly similar to those measured elsewhere along this coast. In 1994, the discharge authorisations for Sellafield were revised, resulting in increased discharges of some radionuclides including technetium-99. In October 1997 a follow-up to the original study was carried out by the RPII and the EHS to determine the current concentrations of artificial radioactivity in the Lough and to assess the effects of Sellafield discharges on the region following the revision of the certificate of authorisation

4

Artificial radioactivity of the Black Sea  

International Nuclear Information System (INIS)

The artificial (technogenic) radioactivity of the Black Sea was studied before and after the Chernobyl event, both during the period of nuclear tests and the moratorium on such tests. Part I describes the forms of artificial radionuclides in seawater. Part II discusses the input into the Black Sea resulting from global fallouts. Part III is devoted to the Chernobyl radioecological consequences. The accumulation of radionuclides in bottom sediments and hydrobionts is considered in Part IV, while Part V is devoted to the modelling of the processes of radionuclide transport in Black Sea waters. 29 tabs., 52 figs., 135 refs

5

Induced radioactivity in LDEF components  

Science.gov (United States)

A systematic study of the induced radioactivity of the Long Duration Exposure Facility (LDEF) is being carried out in order to gather information about the low earth orbit radiation environment and its effects on materials. The large mass of the LDEF spacecraft, its stabilized configuration, and long mission duration have presented an opportunity to determine space radiation-induced radioactivities with a precision not possible before. Data presented include preliminary activities for steel and aluminum structural samples, and activation subexperiment foils. Effects seen in the data show a clear indication of the trapped proton anisotropy in the South Atlantic Anomaly and suggest contributions from different sources of external radiation fluxes.

Harmon, B. A.; Fishman, G. J.; Parnell, T. A.; Laird, C. E.

1992-01-01

6

Medical imaging was boosted by the discovery of artificial radioactivity  

International Nuclear Information System (INIS)

This article draws the history of medical imaging since the discovery of artificial radioactivity in 1934. The author reviews the PET (positron emission tomography) and MRI (magnetic resonance imaging) technologies and presents the recent progress in neuro-sciences that have been made possible by using these 2 technologies. Brain imaging has allowed to show: - the impact of emotions on logical mental processes and on mental performances, - the management of memory in the brain of talented quick reckoners, - the degeneration of neurons, and - the link between autism and the presence of structural and functional anomalies in the brain. (A.C.)

7

Modelling of artificial radioactivity migration in environment: a survey  

International Nuclear Information System (INIS)

The aim of this report is to present a compilation and description of models to assess the environmental behaviour and effects of accidental and routine releases of artificial radioactivity from nuclear power facilities. About 60 models are described and a card is given for each one, to indicate in summarized form its features and data content. This collection is intended to help in developing specific personal models by assembling different parts chosen among the most suitable ones of different models of various degrees of sophistication

8

Natural and artificial radioactivity in the Svalbard glaciers  

International Nuclear Information System (INIS)

Natural and artificial radioactivity in the snow of 10 Svalbard glaciers has been measured from 31 ice core samples, drilled between 1981 and 1993. Of these ice cores, seven exhibit the well-known level arising from the fallout of the 1961-62 atmospheric thermonuclear tests. The second level, due to the Chernobyl accident (26 April 1986), has been detected in all the studied glaciers; the maximum 137Cs fallout reaches 22 Bq kg-1 and shows a high variability. The natural radioactivity, mostly due to 210Pb, shows an in-depth variation which is not governed by its half-life (22.2 years). These measurements serve many glaciological purposes: absolute dating of the snow layers; air-snow transfer and fallout studies; the determination of mean annual mass balances in the accumulation area of glaciers and their associated spatio-temporal variations. (author)

9

Induced radioactivity in LDEF components  

International Nuclear Information System (INIS)

The systematics of induced radioactivity on the Long Duration Exposure Facility (LDEF) were studied in a wide range of materials using low level background facilities for detection of gamma rays. Approx. 400 samples of materials processed from structural parts of the spacecraft, as well as materials from onboard experiments, were analyzed at national facilities. These measurements show the variety of radioisotopes that are produced with half-lives greater than 2 wks, most of which are characteristic of proton induced reactions above 20 MeV. For the higher activity, long lived isotopes, it was possible to map the depth and directional dependences of the activity. Due to the stabilized configuration of the LDEF, the induced radioactivity data clearly show contributions from the anisotropic trapped proton flux in the South Atlantic Anomaly. This effect is discussed, along with evidence for activation by galactic protons and thermal neutrons. The discovery of Be-7 was made on leading side parts of the spacecraft, although this was though not to be related to the in situ production of radioisotopes from external particle fluxes

10

Radioactivity of natural and artificial building materials – a comparative study  

International Nuclear Information System (INIS)

Building materials and their additives contain radioactive isotopes, which can increase both external and internal radioactive exposures of humans. In this study Hungarian natural (adobe) and artificial (brick, concrete, coal slag, coal slag concrete and gas silicate) building materials were examined. We qualified 40 samples based on their radium equivalent, activity concentration, external hazard and internal hazard indices and the determined threshold values of these parameters. Absorbed dose rate and annual effective dose for inhabitants living in buildings made of these building materials were also evaluated. The calculations are based on 226Ra, 232Th and 40K activity concentrations determined by gamma-ray spectrometry. Measured radionuclide concentrations and hence, calculated indices and doses of artificial building materials show a rather disparate distribution compared to adobes. The studied coal slag samples among the artificial building materials have elevated 226Ra content. Natural, i.e. adobe and also brick samples contain higher amount of 40K compared to other artificial building materials. Correlation coefficients among radionuclide concentrations are consistent with the values in the literature and connected to the natural geochemical behavior of U, Th and K elements. Seven samples (coal slag and coal slag concrete) exceed any of the threshold values of the calculated hazard indices, however only three of them are considered to be risky to use according to the fact that the building material was used in bulk amount or in restricted usage. It is shown, that using different indices can lead to different conclusions; hence we recommend considering more of the indices at the same time when building materials are studied. Additionally, adding two times their statistical uncertainties to their values before comparing to thresholds should be considered for providing a more conservative qualification. We have defined radon hazard portion to point to the limitations of the internal hazard considerations based on only measured 226Ra activity concentrations without direct radon measurements. Our data are compared to those obtained in other countries and they provide a good basis to expand the database of radioactivity of building materials and gives information about the safety and situation of the building material industry in this central region of Europe. -- Highlights: ? Radionuclide content and various hazard indices of 40 building materials are studied. ? Data are compared to each other and to results obtained in other studies. ? Radon hazard portion is defined. ? Seven samples exceed any of the thresholds, but three is considered to be hazardous

11

Radioactivity of natural and artificial building materials - a comparative study.  

Science.gov (United States)

Building materials and their additives contain radioactive isotopes, which can increase both external and internal radioactive exposures of humans. In this study Hungarian natural (adobe) and artificial (brick, concrete, coal slag, coal slag concrete and gas silicate) building materials were examined. We qualified 40 samples based on their radium equivalent, activity concentration, external hazard and internal hazard indices and the determined threshold values of these parameters. Absorbed dose rate and annual effective dose for inhabitants living in buildings made of these building materials were also evaluated. The calculations are based on (226)Ra, (232)Th and (40)K activity concentrations determined by gamma-ray spectrometry. Measured radionuclide concentrations and hence, calculated indices and doses of artificial building materials show a rather disparate distribution compared to adobes. The studied coal slag samples among the artificial building materials have elevated (226)Ra content. Natural, i.e. adobe and also brick samples contain higher amount of (40)K compared to other artificial building materials. Correlation coefficients among radionuclide concentrations are consistent with the values in the literature and connected to the natural geochemical behavior of U, Th and K elements. Seven samples (coal slag and coal slag concrete) exceed any of the threshold values of the calculated hazard indices, however only three of them are considered to be risky to use according to the fact that the building material was used in bulk amount or in restricted usage. It is shown, that using different indices can lead to different conclusions; hence we recommend considering more of the indices at the same time when building materials are studied. Additionally, adding two times their statistical uncertainties to their values before comparing to thresholds should be considered for providing a more conservative qualification. We have defined radon hazard portion to point to the limitations of the internal hazard considerations based on only measured (226)Ra activity concentrations without direct radon measurements. Our data are compared to those obtained in other countries and they provide a good basis to expand the database of radioactivity of building materials and gives information about the safety and situation of the building material industry in this central region of Europe. PMID:23246704

Szabó, Zs; Völgyesi, P; Nagy, H É; Szabó, Cs; Kis, Z; Csorba, O

2013-04-01

12

Artificial radioactivity in the environmental samples as IAEA reference materials  

International Nuclear Information System (INIS)

Radioactivity levels of 110mAg, 241Am, 60Co, 134Cs, 137Cs, 106Ru, 125Sb in some biological and environmental materials have been determined by gamma-ray spectrometry in the frame of 15 intercomparison runs organized by IAEA during 1986-1995. The investigated materials were polluted by various nuclear activities, as follows: 1. Nuclear experiments: IAEA-367, sediment collected in 1982 at the Enewetak Atoll (Marshall Islands in the Pacific Ocean). This atoll was used by the USA during 1948-1958 to test nuclear devices; IAEA-368, sediment collected in June 1989 from the Pacific Ocean at the Mururoa Atoll. Since 1966 this atoll has been used by France to test different nuclear devices. 2. Nuclear installations: IAEA-134, cockle flesh of Cardium edule collected in March 1991 from the Irish Sea (Morecambe Bay), England, about 45 km S-E of Sellafield radioactive discharge; IAEA-135, sediment collected in July 1991 in Lune Estuary-England. This area is influenced by the radioactive discharges of the nuclear installations of Sellafield; IAEA-326, soil collected in 1990 in the region of Kursk Atomic Power Plant (Russia). 3. Nuclear accidents (Chernobyl): IAEA-306, sediment collected in the Baltic Sea during October-November 1986; IAEA-307, seaplant Posidonia oceanica, collected in October 1986 in Mediterranean Sea along the shore, in the vicinity of the Principality of Monaco; IAEA-308, mixed seaweeds ality of Monaco; IAEA-308, mixed seaweeds collected in October 1986 in Mediterranean Sea along the shore, in the vicinity of the Principality of Monaco; IAEA-156, clover collected during the summer harvest 1986 in Austria; IAEA-321, milk powder collected in autumn 1987 from a processing plant in Europe; IAEA-352, tuna fish flesh collected in April 1988 in the Western Mediterranean Sea; IAEA-373, grass collected from Kiev region during the summer harvest 1990; IAEA-375, soil collected in July 1990 from Brjansk region, Russia; IAEA-300, sediment collected in July 1992 in Bothnian Sea (Baltic Sea). 4. Uncontaminated by nuclear activities: IAEA-327, Podsolic soil collected in 1990 from the Moscow region and considered uncontaminated by radionuclides of the Chernobyl accident or by other nuclear activities. The results obtained by our laboratory are in good agreement with the certified IAEA data. Generally, the concentration of the artificial radionuclides in the investigated samples is higher than that expected from the influence of global fallout in the intercomparison materials distributed before Chernobyl accident. Concerning the nature of these investigated IAEA reference materials, very high values for the concentration levels of cesium radionuclides especially in IAEA-373 (grass) and IAEA-375 (soil) samples collected in the vicinity of Chernobyl Power Station after the nuclear accident in 1986 were found. High levels of radioactivities for the artificial radionuclides were also determined in the samples collected in the neighbourhood of the nuclear installations, especially in marine sediment (IAEA-135). It is of interest to point out the high concentration of cesium radionuclides in IAEA-300 sediment collected in 1992 in the Baltic Sea in comparison with the IAEA-306 sediment collected also in the Baltic Sea in 1986. It seems to be an increase of the Baltic Sea artificial radioactivity by accumulation in time. Marine sediment constitutes an important component of marine ecosystem since it represents the final sink for any releases of wastes into the sea. These certified radioactive materials are very useful to all laboratories engaged in the radioactive pollution investigations on environmental samples. (authors)

13

Level of natural and artificial radioactivity in Algeria.  

Science.gov (United States)

A national environmental sampling program was carried out during 1993 to determine natural and artificial radionuclides contents in the (0-15 cm) upper layer of the soil. The main objective was to establish a radioactive reference level in the whole territory, since 131I, 134Cs and 137Cs were detected in most of the analysed samples collected right after the Chernobyl accident (May 1986). Soil samples were analysed by direct counting by gamma-ray spectrometry. In addition, terrestrial gamma-ray dose rates in air have been measured out of doors throughout Algeria. In each of the 48 administrative divisions of the country selected sites were chosen to collect soil samples and measure gamma-ray dose rates. The gamma-emitting radionuclides resulting from the radioactive decay of 238U and 232Th, 40K and 137Cs were detected in most of the analysed samples. Radioactivity concentrations in Bq kg-1 dry mass in soil samples of 226Ra, 214Pb, 214Bi, 212Pb, 228Ac, 40K and 137Cs range between (5-176), (2-107), (3-65), (2-97), (3-144), (36-1405) and (0.3-41) respectively. In addition, six selected soil samples were analysed to determine plutonium isotopes contents. Radioactivity concentrations in Bq kg-1 dry mass of 238Pu and 239 + 240Pu vary between (0.012-0.013) and (0.24-0.61) respectively. The dose rates in air measured over the whole country were found to range between 20 and 133 nGy h-1. Presence of 137Cs has been clearly observed. An approach has been made to determine its origin, considering the global fallout, the Chernobyl accident and the French nuclear bomb tests in the 60s as the main potential sources. It is concluded that Algeria has indeed been affected by the Chernobyl accident. PMID:9570102

Baggoura, B; Noureddine, A; Benkrid, M

1998-07-01

14

Problem of Induced Radioactivity in Food Products  

International Nuclear Information System (INIS)

Radioactivity induced by irradiation of foods is caused by the interaction of high-energy radiation with nuclei of food elements. The induced activity is a function of the applied energy, the dose, the sample thickness and the chemical composition of the food. A prime condition for a prediction of the radioactivity induced by irradiation is therefore the knowledge of the chemical composition of the sample. Suitable experimental methods of food analysis are described. Electron and gamma rays are equivalent in the production of induced radioactivity. In the energy range of 0.05 to 10 MeV induced radioactivity is due to stimulation of isomers in (?, ?')-reactions. In this range the 107Ag(?, ?') 107mAg-reaction is responsible for the greatest part of the induced activity. Using a new simplified method of calculation the expected induced radioactivity is estimated, and it is concluded that the activity of these isomers presents no health hazard. By the same method the induced radioactivity in the energy range above 10 MeV, where besides ((?, ?') reactions the possibility of (?, n) reactions exists, is calculated for the principal foodstuffs. Methods for experimental verification of calculated activities are discussed. The magnitude of induced radioactivity due to single elements is compared with the total maximal permissible concentration (MPC) of nuclides in foods (10-7 ?Ci/g food). Factors which determine the maximum permissible retermine the maximum permissible radiation energy and dose are discussed. (author)

15

Natural and artificial radioactivity determination of some medicinal plants  

International Nuclear Information System (INIS)

Several medicinal plants used in Italy were analysed to determine natural and artificial radioactivity in those parts (leaves, fruits, seeds, roots, peduncles, flowers, barks, berries, thallus) used generally as remedies. The radionuclides were determined by alpha (238U, 210Po) and gamma (214Pb-Bi, 210Pb, 40K and 137Cs) spectrometry. 238U ranged between dry-1; 210Po between dry-1; 214Pb-214Bi between dry-1; 210Pb between dry-1; 40K between 66.2 and 3582.0 Bq kgdry-1; 137Cs between dry-1. The percentage of 210Po extraction in infusion and decoction was also determined; the arithmetical mean value of percentage of 210Po extraction resulted 20.7 ± 7.5.

16

Evaluation of induced radioactivity in irradiated foods  

International Nuclear Information System (INIS)

This report was made by Japanese Research Association For Food Irradiation from the minutes of Masakazu FURUTA's lecture in the third Food Irradiation Subcommittee of Atomic Energy Commission. Masakazu FURUTA published that the induced radioactivity of food by gamma-ray of Co-60 or Ce-137, 5 MeV X-ray and 10 MeV electron beam was out of question from evaluating the values of literature by theoretical calculation. The induced radioactivity in pepper irradiated by gamma-ray of Co-60 or Ce-137, 5 MeV X-ray and 10 MeV electron beam showed lower values than natural radiation. The induced radioactivity in the food irradiated, evaluation of generation of nuclear reactions, the theoretical evaluation method of induced radioactivity, and evaluation of irradiated radioactivity in irradiated peppers are described. (S.Y.)

17

Artificial radioactivity on the coasts of Northern Ireland  

International Nuclear Information System (INIS)

In Northern Ireland, measurements of artificial radioactivity have been made in inshore seawater, beach sand and mud, sea spray, the air and material deposited from the air, and in coastal soil. The objective was to determine the levels in the coastal environment and also to assess the magnitude of transport of radioactivity from sea to land in sea spray. The results would provide a basis for the development of a model describing sea to land transfer, and allowing the resulting population exposure to be assessed. The results showed the presence of plutonium isotopes, 241Am and 137Cs in some samples of each of the media measured, but concentrations were low in all cases. Large variation in the concentrations in seawater and beach sediment were attributed to variations in dispersion and in the characteristics of the sediment. Sea to land transfer of actinides was detected in samples of sea spray and in air and deposition measurements. Only at some sites on the east coast could the resulting accumulation in soil close to the beach be distinguished from fallout. Following May 1986 137Cs from Chernobyl could be detected in air and in atmospheric deposition. A preliminary assessment of the exposure of the population to the actinides and 137Cs in all the media showed that the resulting dose is a small fraction of the recognised limit. (author)

18

Studies of induced radioactivity at the AGS  

International Nuclear Information System (INIS)

With the goals of higher proton intensities, along with the many modes the AGS now runs and those being commissioned to run, we have begun detailed studies of the beam induced radioactivity in the AGS

19

Artificial radioactivity in tide washed pastures in south west Scotland  

International Nuclear Information System (INIS)

A study has been carried out to determine the impact of Sellafield discharges on the levels of radioactivity in tide washed pastures in south west Scotland. The likely areas of tidal inundations along the Nith, Urr, Dee, Fleet and Cree (including nearby Bladnoch) rivers were assessed using maps and aerials photographs. These were then visited and gamma radiation measurements taken at regular intervals to enable the external dose from anthropogenic nuclides to be estimated. A further survey followed where soil cores were taken from the areas on each river where the external dose appeared highest and analysed for a range of artificial radionuclides. The levels of 137Cs, 134Cs, 238Pu, 239+240Pu and 241Am found, although small, were clearly in excess of the background from other sources. A habit survey was carried out to provide site specific information of tide washed pasture usage, which, with the spatial radionuclide data was used to estimate doses to appropriate critical groups. The maximum annual dose calculated to arise was 60 ?Sv which is less than 6% of the ICRP principal dose limit of 1 mSv. (author)

20

Induced radioactivity from industrial radiation processing  

Science.gov (United States)

Analytic expressions are developed for quantitative analysis of radioactivity induced by radiation processing of products with electrons or photons. These expressions provide reasonable estimates of induced activity much faster than Monte Carlo simulations. Analysis of radioactivity from processing of meat with 10 MeV electrons shows an induced activity of less than 10 mBq/(kgkGy) just after irradiation. This is 4 orders of magnitude less than the natural background activity of about 100 Bq/kg found in meat. Five days after processing the induced activity will reduce by a factor of 300.

Lone, M. A.

1990-12-01

21

Natural and induced radioactivity in food  

International Nuclear Information System (INIS)

One of the first questions often asked about irradiated food is whether it is radioactive. Not many people understand that food and any natural substance contains natural radioactivity which can be measurable. It is therefore important to put the issue on natural radioactivity and possible induced radioactivity in food in perspective. While there is a clear consensus among the scientific community that no radioactivity is induced when food is irradiated by gamma rays from cobalt-60 or cesium-137, electron generated by a machine with energy less than 10 million electron volt (MeV) or X rays produced generated by a machine with energy less than 5 MeV. However, data to this effect were published many years ago and are not easy to find. As food irradiation is gaining wide acceptance in many countries, it was considered timely to compile data on natural and induced radioactivity in food into one document. We are grateful to A. Brynjolfsson, one of the few experts who have the knowledge on this subject as well as wide experience on food irradiation, who collected, compiled and evaluated all data on this subject into one report. This publication provides clear explanations not only why radioactivity cannot be induced in food irradiated by radiation sources mentioned above but to what extent the increase in dose or energy level of radiation sources would induce significantly radioactivity in food. The compilation of such data was prompted by a desire to increase the energy limit and the absorbed dose based on the need to irradiate thicker samples of food and to use sterilizing dose up to 60 kGy. This publication concluded that the increase in radiation background dose from consumption of food irradiated to an average dose up to 60 kGy with gamma rays from cobalt- 60 or cesium-137, with 10 MeV electrons or with 5 MeV X rays is insignificant. In addition, food irradiated with X ray with energy up to 7.5 MeV to a dose of 30 kGy has radioactivity well below natural radioactivity in unirradiated food. There are no adverse effect from consumption of irradiated food which contains radioactivity well below background level. This publication should provide valuable information to anyone who has interest in food irradiation especially regulatory authorities for food safety and radiation applications as well as to consumers who might be interested in scientific matters of irradiated food

22

Multiprotocol-induced plasticity in artificial synapses  

Science.gov (United States)

We suggest a `universal' electrical circuit for the realization of an artificial synapse that exhibits long-term plasticity induced by different protocols. The long-term plasticity of the artificial synapse is basically attributed to the nonvolatile resistance change of the bipolar resistive switch in the circuit. The synaptic behaviour realized by the circuit is termed `universal' inasmuch as (i) the shape of the action potential is not required to vary so as to implement different plasticity-induction behaviours, activity-dependent plasticity (ADP) and spike-timing-dependent plasticity (STDP), (ii) the behaviours satisfy several essential features of a biological chemical synapse including firing-rate and spike-timing encoding and unidirectional synaptic transmission, and (iii) both excitatory and inhibitory synapses can be realized using the same circuit but different diode polarity in the circuit. The feasibility of the suggested circuit as an artificial synapse is demonstrated by conducting circuit calculations and the calculation results are introduced in comparison with biological chemical synapses.We suggest a `universal' electrical circuit for the realization of an artificial synapse that exhibits long-term plasticity induced by different protocols. The long-term plasticity of the artificial synapse is basically attributed to the nonvolatile resistance change of the bipolar resistive switch in the circuit. The synaptic behaviour realized by the circuit is termed `universal' inasmuch as (i) the shape of the action potential is not required to vary so as to implement different plasticity-induction behaviours, activity-dependent plasticity (ADP) and spike-timing-dependent plasticity (STDP), (ii) the behaviours satisfy several essential features of a biological chemical synapse including firing-rate and spike-timing encoding and unidirectional synaptic transmission, and (iii) both excitatory and inhibitory synapses can be realized using the same circuit but different diode polarity in the circuit. The feasibility of the suggested circuit as an artificial synapse is demonstrated by conducting circuit calculations and the calculation results are introduced in comparison with biological chemical synapses. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03405h

Kornijcuk, Vladimir; Kavehei, Omid; Lim, Hyungkwang; Seok, Jun Yeong; Kim, Seong Keun; Kim, Inho; Lee, Wook-Seong; Choi, Byung Joon; Jeong, Doo Seok

2014-11-01

23

Linear accelerator therapeutic dose - induced radioactivity dependence  

International Nuclear Information System (INIS)

Full text: Radiotherapy with the use of linear medical accelerators is widely applied method in oncological treatment. Patient's irradiation is carried out with the use of primary electron as well as secondary X-ray radiation, particularly high - energy beams above 10 MeV. From physical point of view probability of nuclear reactions during emission of these beams could not be neglected. This means that therapeutic beams induce additional radioactivity and contribute to neutron flux production (via photo- and electronuclear reactions (?,n) and (e,e'n) respectively), which occur mainly in accelerator head. Those effects generally are undesired in this kind of treatment. Neutron capture reaction contributes to induced activity too. Although therapeutic beam interactions are limited to irradiation field, neutron flux is significant over the whole therapeutic room. Therefore induced activity occurs also outside the accelerator beam. The distance from isocentre larger, the contribution of photonuclear reactions is smaller and simple capture reactions become dominant, as neutrons are reaching resonance and thermal energies (cross sections of (n,?) reactions are larger for slow neutrons than for fast ones). All objects inside therapeutic room may emit gamma radiation as a result of inducing radioactivity, including patient's body. In this paper we discuss the dependence between therapeutic dose and activity induced in mammal bones. This activity leads to gamma ray emission is activity leads to gamma ray emission registered by the high purity germanium detector as well as the scintillation probe. Results of investigations presented here are focused on activation effects which occur during emission of 15 MV and 20 MV therapeutic X-ray beams. The purpose is to describe how therapeutic conditions (the dose and time of irradiation) influence induced radioactivity. Preliminary studies of time scale of studied phenomenon (decay rate, calculation of half - life and identification of main isotopes involved in this dynamic process) is given. Correlation between therapeutic dose and activity inside the patient's body induced during high - energy beam irradiation could be useful for in vivo dose dosimetry

24

Daily measurements of natural and artificial radioactivity in 1960  

International Nuclear Information System (INIS)

Daily numerical results of measures concerning ? activity of the air, either from natural, owing to thoron, or from artificial, owing to active aerosols origin, will be found in this statement. The all results are expressed in ??curie / m3 of air. Proceedings of measure and technic of standardization, which were the matter of anterior papers, have not been discussed once more here. (author)

25

Investigations on natural and artificial radioactivity in Dobrogea  

International Nuclear Information System (INIS)

To evaluate potential impact of radioactive emissions of Cernavoda NPP on the environment, preliminary investigations on the radioactivity in the area and surroundings were carried out. Consequently the concentration of H-3 was determined in vine (leaves and sap) and viticulture products (grapes and wine) and the concentrations of K-40, Cs-137 and Sr-90 were measured in soil, surface water and aquatic sediments. The corresponding specific activities are generally characteristic for areas less contaminated by Chernobyl nuclear accident (except the northern area of Dobrogea where the Chernobyl fallout has produced a rather high contamination of the environment). For tritium, the results show values fitted in the range of natural background. (author)

26

Some regularities in artificial radioactivity distribution in rain droplets  

International Nuclear Information System (INIS)

Investigations of the sup(210)Po distribution in rain droplets were carried and the methods of the determination of parameters characterizing the rain droplets were described. Conclusions from the material of 9 natural experiments being performed in 1972-1980 were drawn. The ranges of the modal, predominant and effective radii of raindrops were measured and their mean values were calculated. It was shown that by increase of modal, predominant and effective radii the number of raindrops with these radii in comparison with the all raindrops decreased. During a rain the droplets of optimal sizes (r=0.68-1.02 mm) existed; their number, mass and amount of the sup(210)Po washed out by them were maximal. A dependence of raindrops tracer radioactivity on the size and mass of raindrops was described

27

Detecting artificial airborne radioactivity: on-line monitoring of external dose rate near an aerosol filter  

International Nuclear Information System (INIS)

An early warning method based on external dose rate monitoring near an aerosol filter can be used to detect artificial airborne radioactivity. A theory is presented for calculating the external dose rate in the measurement geometry involved. Airborne radionuclides and radionuclides collected by the filter and deposited on the ground are considered. Delay time from the arrival of a radioactive cloud to a tentative warning level of 0.4?Gy.h-1 is calculated for two cases: for a constant activity concentration of 137Cs and for a group of fission products. The simulations indicate that, in terms of activity concentrations, a warning level of -3 of artificial airborne radionuclides can be attained. This activity concentration corresponds roughly to an external dose rate of 1 nG.h-1, which is about 2 orders of magnitude below a typical, natural, ground-level dose rate. (Author)

28

Detecting artificial airborne radioactivity: on-line monitoring of external dose rate near an aerosol filter  

Energy Technology Data Exchange (ETDEWEB)

An early warning method based on external dose rate monitoring near an aerosol filter can be used to detect artificial airborne radioactivity. A theory is presented for calculating the external dose rate in the measurement geometry involved. Airborne radionuclides and radionuclides collected by the filter and deposited on the ground are considered. Delay time from the arrival of a radioactive cloud to a tentative warning level of 0.4{mu}Gy.h{sup -1} is calculated for two cases: for a constant activity concentration of {sup 137}Cs and for a group of fission products. The simulations indicate that, in terms of activity concentrations, a warning level of <10 Bq.m{sup -3} of artificial airborne radionuclides can be attained. This activity concentration corresponds roughly to an external dose rate of 1 nG.h{sup -1}, which is about 2 orders of magnitude below a typical, natural, ground-level dose rate. (Author).

Leppanen, A.; Toivonen, H. [Finnish Centre for Radiation and Nuclear Safety (STUK), Helsinki (Finland)

1997-12-01

29

75th anniversary of the artificial production of radioactive elements by Irene and Frederic Joliot-Curie  

International Nuclear Information System (INIS)

Following the discovery of X-rays in 1895, of radioactivity in 1896, of radium and polonium in 1898, of the positron in 1932 and the neutron also in 1932, the next most important discovery was that of artificial production of radioactive elements in 1934 and the 75th anniversary of this event is celebrated by this short article. (author)

30

Application of two-barrier model of radioactive agent transport in sea water for analyzing artificial radionuclide release from containers with radioactive waste dumped in Kara Sea  

International Nuclear Information System (INIS)

Modeling of artificial radionuclide transport in sea water is crucial for prognosis of radioecological situation in regions where dumping of radioactive waste had been made and/or accidents with nuclear submarines had taken place. Distribution of artificial radionuclides in bottom sediments can be a detector of radionuclide release from dumped or sunk objects to marine environment. Proper model can determine the dependence between radionuclide distribution in sediments and radionuclide release. Following report describes two-barrier model of radioactive agent transport in sea water. It was tested on data from 1994 - 2013 expeditions to Novaya Zemlya bays, where regular dumping of solid radioactive waste was practiced by the former USSR from the early 1960's until 1990. Two-barrier model agrees with experimental data and allows more accurate determination of time and intensity of artificial radionuclide release from dumped containers. (authors)

31

Application of two-barrier model of radioactive agent transport in sea water for analyzing artificial radionuclide release from containers with radioactive waste dumped in Kara Sea  

Energy Technology Data Exchange (ETDEWEB)

Modeling of artificial radionuclide transport in sea water is crucial for prognosis of radioecological situation in regions where dumping of radioactive waste had been made and/or accidents with nuclear submarines had taken place. Distribution of artificial radionuclides in bottom sediments can be a detector of radionuclide release from dumped or sunk objects to marine environment. Proper model can determine the dependence between radionuclide distribution in sediments and radionuclide release. Following report describes two-barrier model of radioactive agent transport in sea water. It was tested on data from 1994 - 2013 expeditions to Novaya Zemlya bays, where regular dumping of solid radioactive waste was practiced by the former USSR from the early 1960's until 1990. Two-barrier model agrees with experimental data and allows more accurate determination of time and intensity of artificial radionuclide release from dumped containers. (authors)

Grishin, Denis S.; Laykin, Andrey I.; Kuchin, Nickolay L.; Platovskikh, Yuri A. [Krylov State Research Center, Saint Petersburg, 44 Moskovskoe shosse, 196158 (Russian Federation)

2014-07-01

32

Results of concentration measurements of artificial radioactive aerosols in the lower atmosphere  

International Nuclear Information System (INIS)

This report gives the results of the measurements of artificial gross-?-radioactivity in aerosols in the lower atmosphere; these measurements have been made by the Electronic Physics Service of the Electronic Department, and by the Atmospheric Physics Laboratory of the Paris Science Faculty. The measurements were begun in September 1956 and were continued in an increasing number of stations both in France and in the rest of the world. The present report deals with the period up to the end of august 1961, that is up to the end of the nuclear moratorium. After recalling the constitution and the properties of radioactive aerosols present in the atmosphere, the authors describe the measurement methods, estimate their accuracy and discuss various aspects of the results. (authors)

33

Simulation of induced radioactivity for Heavy Ion Medical Machine  

OpenAIRE

For radiation protection and environmental impact assessment purpose, the radioactivity induced by carbon ion of Heavy Ion Medical Machine (HIMM) was studied. Radionuclides in accelerator component, cooling water and air at target area which are induced from primary beam and secondary particles are simulated by FLUKA Monte Carlo code. It is found that radioactivity in cooling water and air is not very important at the required beam intensity and energy which is needed for tr...

Jun-kui, Xu; You-wu, Su; Wu-yuan, Li; Wang, Mao; Jia-wen, Xia; Xi-meng, Chen; Wei-wei, Yan; Chong, Xu

2013-01-01

34

Artificial and natural radioactivity in edible mushrooms from Sao Paulo, Brazil  

International Nuclear Information System (INIS)

Environmental biomonitoring has demonstrated that organisms such as crustaceans, fish and mushrooms are useful to evaluate and monitor both ecosystem contamination and quality. Particularly, some mushroom species have a high capacity to retain radionuclides and some toxic elements from the soil and the air. The potential of mushrooms to accumulate radionuclides in their fruit-bodies has been well documented. However, there are no studies that determine natural and artificial radionuclide composition in edible mushrooms, in Brazil. Artificial (137Cs) and natural radioactivity (40K, 226Ra, 228Ra) were determined in 17 mushroom samples from 3 commercialized edible mushroom species. The edible mushrooms collected were Agaricus sp., Pleurotus sp. and Lentinula sp. species. The activity measurements were carried out by gamma spectrometry. The levels of 137Cs varied from 1.45 ± 0.04 to 10.6 ± 0.3 Bq kg?1, 40K levels varied from 461 ± 2 to 1535 ± 10 Bq kg?1, 226Ra levels varied from 14 ± 3 to 66 ± 12 Bq kg?1 and 228Ra levels varied from 6.2 ± 0.2 to 54.2 ± 1.7 Bq kg?1. 137Cs levels in Brazilian mushrooms are in accordance with the radioactive fallout in the Southern Hemisphere. The artificial and natural activities determined in this study were found to be below the maximum permissible levels as established by national s established by national legislation. Thus, these mushroom species can be normally consumed by the population without any apparent risks to human health. - Highlights: ? 137Cs, 40K, 226Ra and 228Ra in edible mushroom samples. ? There are very few data about natural radionuclides in mushrooms. ? The radionuclide activities were below the national maximum permissible levels. ? Mushrooms can be consumed by the population without any apparent risks.

35

Artificial magnetic field induced by an evanescent wave  

Science.gov (United States)

Cold atomic gases are perfect laboratories for realization of quantum simulators. In order to simulate solid state systems in the presence of magnetic fields special effort has to be made because atoms are charge neutral. There are different methods for realization of artificial magnetic fields, that is the creation of specific conditions so that the motion of neutral particles mimics the dynamics of charged particles in an effective magnetic field. Here, we consider adiabatic motion of atoms in the presence of an evanescent wave. Theoretical description of the adiabatic motion involves artificial vector and scalar potentials related to the Berry phases. Due to the large gradient of the evanescent field amplitude, the potentials can be strong enough to induce measurable effects in cold atomic gases. We show that the resulting artificial magnetic field is able to induce vortices in a Bose-Einstein condensate trapped close to a surface of a prism where the evanescent wave is created. We also analyze motion of an atomic cloud released from a magneto-optical trap that falls down on the surface of the prism. The artificial magnetic field is able to reflect falling atoms that can be observed experimentally. PMID:25567430

Mochol, Ma?gorzata; Sacha, Krzysztof

2015-01-01

36

Radioactivity  

International Nuclear Information System (INIS)

This educative booklet give a general overview of radioactivity: history, structure of matter, radiations, radioactivity law, origin of radioactivity, radioactivity uses, radioprotection and measurement units. (J.S.)

37

Radioactivity: A Natural Phenomenon.  

Science.gov (United States)

Discussed is misinformation people have on the subject of radiation. The importance of comparing artificial source levels of radiation to natural levels is emphasized. Measurements of radioactivity, its consequences, and comparisons between the risks induced by radiation in the environment and from artificial sources are included. (KR)

Ronneau, C.

1990-01-01

38

Determination of natural and artificial radioactivity in soil at North Lebanon province.  

Science.gov (United States)

The concentrations of natural and artificial radionuclides at 57 sampling locations along the North Province of Lebanon are reported. The samples were collected from uncultivated areas in a region not previously reported. The samples were analyzed by gamma spectrometers with High Purity Germanium detectors of 30% and 40% relative efficiency. The activity concentrations of primordial naturally occurring radionuclides of (238)U, (232)Th, and (40)K varied between 4-73 Bq kg(-1), 5-50 Bq kg(-1), and 57-554 Bq kg(-1) respectively. The surface activity concentrations due to the presence of these radionuclides were calculated and Kriging-geostatistical method was used to plot the obtained data on the Lebanese radioactive map. The results for (238)U, (232)Th, and (40)K ranged from 0.2 kBq m(-2) to 9 kBq m(-2), from 0.2 kBq m(-2) to 3 kBq m(-2), and from 3 kBq m(-2) to 29 kBq m(-2) respectively. For the anthropogenic radionuclides, the activity concentrations of (137)Cs founded in soil ranged from 2 Bq kg(-1) to 113 Bq kg(-1), and the surface activity concentration from 0.1 kBq m(-2) to 5 kBq m(-2). The total absorbed gamma dose rates in air from natural and artificial radionuclides in these locations were calculated. The minimum value was 6 nGy h(-1) and the highest one was 135 nGy h(-1) with an average of 55 nGy h(-1) in which the natural terrestrial radiation contributes in 99% and the artificial radionuclides mainly (137)Cs contributes only in 1%. The total effective dose calculated varied in the range of 7 ?Sv y(-1) and 166 ?Sv y(-1) while the average value was 69 ?Sv y(-1) which is below the permissible limit 1000 ?Sv y(-1). PMID:23498968

El Samad, O; Baydoun, R; Nsouli, B; Darwish, T

2013-11-01

39

Determination of natural and artificial radioactivity in soil at North Lebanon province  

International Nuclear Information System (INIS)

The concentrations of natural and artificial radionuclides at 57 sampling locations along the North Province of Lebanon are reported. The samples were collected from uncultivated areas in a region not previously reported. The samples were analyzed by gamma spectrometers with High Purity Germanium detectors of 30% and 40% relative efficiency. The activity concentrations of primordial naturally occurring radionuclides of 238U, 232Th, and 40K varied between 4–73 Bq kg?1, 5–50 Bq kg?1, and 57–554 Bq kg?1 respectively. The surface activity concentrations due to the presence of these radionuclides were calculated and Kriging-geostatistical method was used to plot the obtained data on the Lebanese radioactive map. The results for 238U, 232Th, and 40K ranged from 0.2 kBq m?2 to 9 kBq m?2, from 0.2 kBq m?2 to 3 kBq m?2, and from 3 kBq m?2 to 29 kBq m?2 respectively. For the anthropogenic radionuclides, the activity concentrations of 137Cs founded in soil ranged from 2 Bq kg?1 to 113 Bq kg?1, and the surface activity concentration from 0.1 kBq m?2 to 5 kBq m?2. The total absorbed gamma dose rates in air from natural and artificial radionuclides in these locations were calculated. The minimum value was 6 nGy h?1 and the highest one was 135 nGy h?1 with an average of 55 nGy h?1 in which the natural terrestrial radiation contributes in 99% and the artificial radionuclides mainly 137Cs contributes only in 1%. The total effective dose calculated varied in the range of 7 ?Sv y?1 and 166 ?Sv y?1 while the average value was 69 ?Sv y?1 which is below the permissible limit 1000 ?Sv y?1

40

Metal Complexes Containing Natural and and Artificial Radioactive Elements and Their Applications  

Directory of Open Access Journals (Sweden)

Full Text Available Recent advances (during the 2007–2014 period in the coordination and organometallic chemistry of compounds containing natural and artificially prepared radionuclides (actinides and technetium, are reviewed. Radioactive isotopes of naturally stable elements are not included for discussion in this work. Actinide and technetium complexes with O-, N-, N,O, N,S-, P-containing ligands, as well ?-organometallics are discussed from the view point of their synthesis, properties, and main applications. On the basis of their properties, several mono-, bi-, tri-, tetra- or polydentate ligands have been designed for specific recognition of some particular radionuclides, and can be used in the processes of nuclear waste remediation, i.e., recycling of nuclear fuel and the separation of actinides and fission products from waste solutions or for analytical determination of actinides in solutions; actinide metal complexes are also usefulas catalysts forcoupling gaseous carbon monoxide,as well as antimicrobial and anti-fungi agents due to their biological activity. Radioactive labeling based on the short-lived metastable nuclide technetium-99m (99mTc for biomedical use as heart, lung, kidney, bone, brain, liver or cancer imaging agents is also discussed. Finally, the promising applications of technetium labeling of nanomaterials, with potential applications as drug transport and delivery vehicles, radiotherapeutic agents or radiotracers for monitoring metabolic pathways, are also described.

Oxana V. Kharissova

2014-07-01

41

Monitoring artificial radioactivity in the Nordic countries. BER-2 final report  

International Nuclear Information System (INIS)

This final report of the Nordic Nuclear Safety Research Project BER-2 gives detailed information on the monitoring of artificial radioactivity in the Nordic countries (Denmark, Finland, Iceland, Norway and Sweden). A comparison shows that for early warning the Nordic countries use a mix of stations measuring external gamma radiation and stations measuring airborne radioactivity. There is a trade-off between fast alarms and the sensitivity threshold. Total gamma measuring stations cannot detect increases smaller than the variations of normal background. Some stations, notably all Danish stations, are equipped with sodium iodide (NaI) type detectors, and operated in such a way that stray peaks due to an increase in the natural radon background can be subtracted. A Nordic Radiation Data Exchange System has been set up and tested on a trial basis. This system focuses on dose rate data from the automatic gamma monitoring stations. An important goal achieved in the project was to determine which data is essential, and to specify a common format for the data exchange. Various telecommunication methods have been tested, and the actual transfer of monitoring results between the Nordic countries was started. It is recommended as a future approach that every country appoint one organization with the responsibility of operating a national information data base, which can be commonly accessed from all the Nordic countries. A procedure for establishing a system of this type has been outlined

42

The use and production of artificial radioactive isotopes in Hungary over the past 25 years  

International Nuclear Information System (INIS)

The history of application of artificial radioactive isotopes is reviewed. The first isotope consignement arrived in Hungary in 1954. Between 1954 and 1957 appropriate laboratories were constructed, new techniques developed and specialists were trained. The central coordinating organ, the National Atomic Energy Committee, was founded in 1956. The Institute of Isotopes was established in 1959, the tasks of which include the production and distribution of radioactive preparations, extensive research for new types of radiation sources as well as the development of new methods for activity measurement. Between 1957 and 1970 the development and production of measuring instruments have become especially important. More and more conferences and meetings were organized, basis institutes with specialized programs were founded. The cooperation among the Comecon-countries has become extensive in the 1960-es; in the 1970-es the emphasis has been put on specific tasks. Nowadays more than 1000 different preparations and a total activity of approx. 17000 TBq are produced in a year. (L.E.)

43

Study of the artificial radioactivity of the marine medium using gamma spectrometry (1962-1966)  

International Nuclear Information System (INIS)

The results described in this study are relative to the artificial radioactivity of such elements as zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 and praseodymium-144 which were present in the atmospheric fallout between 1962 and 1964, and their incidence in superficial marine waters. Various physical, chemical or biological processes are studied by a high sensitivity gamma ray spectrometry technic, using those radioelements as 'tracers'. The change of state in sea water of an important fraction (about 50 per cent) of the radioactive particles going into the soluble phase - this phenomenon was not expected for those radioelements - controls the processes of accumulation in the planktonic biomass and the diffusion towards deeper waters. On the other hand, an 'in situ' spectrometry method is described. It enables the direct measurement in the sea of very low concentrations of some gamma ray emitters. The application of this method has made possible to carry out numerous observations in the surface waters of the Western Mediterranean sea and in the Bay of Biscay. It is shown that the mixing depth is closely connected to the depth of the thermocline. An accumulation process at this level is observed. The diffusion coefficients are similar to the thermal turbulent coefficient. The existence during several months of 'compartments' is established for the surface waters of the Bay of Biscay. From the establishment of the budget of fall-out, a comparative study shows that the rate of radioactive fallout on the maritime zone considered is always two to three times higher than on the neighbouring continental regions. Several explanations of this phenomenon are discussed. (author)

44

Artificial neural networks in the evaluation of the radioactive waste drums activity  

International Nuclear Information System (INIS)

The mathematical techniques are becoming more important to solve geometry and standard identification problems. The gamma spectrometry of radioactive waste drums would be a complex solution problem. The main difficulty is the detectors calibration for this geometry; the waste is not homogeneously distributed inside the drums, therefore there are many possible combinations between the activity and the position of these radionuclides inside the drums, making the preparation of calibration standards impracticable. This work describes the development of a methodology to estimate the activity of a 200 L radioactive waste drum, as well as a mapping of the waste distribution, using Artificial Neural Network. The neural network data set entry obtaining was based on the possible detection efficiency combination with 10 sources activities varying from 0 to 74 x 103 Bq. The set up consists of a 200 L drum divided in 5 layers. Ten detectors were positioned all the way through a parallel line to the drum axis, from 15 cm of its surface. The Cesium -137 radionuclide source was used. The 50 efficiency obtained values (10 detectors and 5 layers), combined with the 10 source intensities resulted in a 100,000 lines for 15 columns matrix, with all the possible combinations of source intensity and the Cs-137 position in the 5 layers of the drum. This archive was divided in 2 parts to compose the set of training: input and target files. The MatLab 7.0 module of neural networks was used for training. The net architecture has 10 neurons in the input layer, 18 in the hidden layer and 5 in the output layer. The training algorithm was the 'traincgb' and after 300 'epoch s' the medium square error was 0.00108172. This methodology allows knowing the detection positions answers in a heterogeneous distribution of radionuclides inside a 200 L waste drum; in consequence it is possible to estimate the total activity of the drum in the training neural network limits. The results accuracy depends on the way that the waste drum is divided and to the amount of intensities that it is interpolated between the minimum and maximum limits. The use of the Artificial Neural Networks associated to Monte Carlo Method showed to be efficient in the isotopic characterization of radioactive waste drums. (authors)

45

Simulation of induced radioactivity for Heavy Ion Medical Machine  

CERN Document Server

For radiation protection and environmental impact assessment purpose, the radioactivity induced by carbon ion of Heavy Ion Medical Machine (HIMM) was studied. Radionuclides in accelerator component, cooling water and air at target area which are induced from primary beam and secondary particles are simulated by FLUKA Monte Carlo code. It is found that radioactivity in cooling water and air is not very important at the required beam intensity and energy which is needed for treatment, radionuclides in accelerator component may cause some problem for maintenance work, suitable cooling time is needed after the machine are shut down.

Jun-Kui, Xu; Wu-Yuan, Li; Wang, Mao; Jia-Wen, Xia; Xi-Meng, Chen; Wei-Wei, Yan; Chong, Xu

2013-01-01

46

Monitoring induced denitrification in an artificial aquifer recharge system.  

Science.gov (United States)

As demands on groundwater increase, artificial recharge is becoming a common method for enhancing groundwater supply. The Llobregat River is a strategic water supply resource to the Barcelona metropolitan area (Catalonia, NE Spain). Aquifer overexploitation has leaded to both a decrease of groundwater level and seawater intrusion, with the consequent deterioration of water quality. In the middle section of the aquifer, in Sant Vicenç del Horts, decantation and infiltration ponds recharged by water from the Llobregat River (highly affected from wastewater treatment plant effluents), were installed in 2007, in the framework of the ENSAT Life+ project. At the bottom of the infiltration pond, a vegetal compost layer was installed to promote the growth of bacteria, to induce denitrification and to create favourable conditions for contaminant biodegradation. This layer consists on a mixture of compost, aquifer material, clay and iron oxide. Understanding the fate of contaminants, such as nitrate, during artificial aquifer recharge is required to evaluate the impact of artificial recharge in groundwater quality. In order to distinguish the source of nitrate and to evaluate the capability of the organic reactive layer to induce denitrification, a multi-isotopic approach coupled with hydrogeochemical data was performed. Groundwater samples, as well as river samples, were sampled during artificial and natural recharge periods. The isotopic analysis included: ?15N and ?18O of dissolved nitrate, ?34S and ?18O of dissolved sulphate, ?13C of dissolved inorganic carbon, and ?2H and ?18O of water. Dissolved nitrate isotopic composition (?15NNO3 from +9 to +21 o and ?18ONO3 from +3 to +16 ) demonstrated that heterotrophic denitrification induced by the reactive layer was taking place during the artificial recharge periods. An approximation to the extent of nitrate attenuation was calculated, showing a range between 95 and 99% or between 35 and 45%, by using the extreme literature ?N values of -4o and -22o respectively (Aravena and Robertson, 1998; Pauwels et al., 2000). Ongoing denitrification batch experiments will allow us to determine the specific nitrogen and oxygen isotopic fractionation induced by the organic reactive layer, in order to estimate more precisely the extent of denitrification during artificial aquifer recharge. These results confirmed that the reactive layer induces denitrification in the recharge ponds area, proving the usefulness of an isotopic approach to characterize water quality improvement occurring during artificial aquifer recharge. References 1. Aravena, R., Robertson, W.D., 1998. Use of multiple isotope tracers to evaluate denitrification in ground water: Study of nitrate from a large-flux septic system plume. Ground Water, 36(6): 975-982. 2. Pauwels, H., J.C., Kloppmann, W., 2000. Denitrification and mixing in a schist aquifer: Influence on water chemistry and isotopes. Chemical Geology, 168(3-4): 307-324. Acknowledgment This study was supported by the projects CGL2011-29975-C04-01 from the Spanish Government, 2009SGR-00103 from the Catalan Government and ENPI/2011/280-008 from the European Commission. Please fill in your abstract text.

Grau-Martinez, Alba; Torrentó, Clara; Folch, Albert; Domènech, Cristina; Otero, Neus; Soler, Albert

2014-05-01

47

Induced Radioactivity in Recovered Skylab Materials. [gamma ray spectra  

Science.gov (United States)

Four radioactive isotopes found in aluminum and stainless steel samples from Skylab debris were recovered in Australia. The low-level activity was induced by high-energy protons and neutrons in the space environment. Measurements of the specific activities are given.

Fishman, G. J.; Meegan, C. A.

1980-01-01

48

Natural and artificial atmospheric radioactivity in aerosols collected in Barcelona (Spain)  

International Nuclear Information System (INIS)

Radioactivity in the Barcelona area is continuously being measured at the Radioactivity Analysis Laboratory of the Institute of Energy Technologies, Technical University of Catalonia, as it is part of a Spanish Sparse network for radiation monitoring. High sensitivity measurements are made in this laboratory. Airborne particulate sampling is carried out by pumping air through polypropylene filters at a flow rate of 800 m3/h. Measurements of radionuclides were carried out by ?-ray spectrometric analysis of particulate samples collected weekly. The results for the naturally occurring 7Be, 210Pb, 40K, 214Bi, 214Pb, 228Ac and 208Tl and for the artificial radionuclide 137Cs, during the period from January 2001 to December 2004, are given in this report. The aim of the present in paper is to find the underlying causes of variations of radionuclide concentrations in the air Barcelona and the correlation with season, rainfall, airborne particulate material, wind speed and wind direction. The annual average values obtained for 7Be, 210Pb and 137Cs during the investigation period were in good agreement with those measured in other countries. During the investigation period, the radionuclides 212Pb and 208Tl, 214Bi and 214Pb, 7Be and 210Pb, correlate significantly with each other. The correlation coefficients obtained were 0.99, 0.73 and 0.71 respectively with a confidence level of 99%. 7Be and 210Pb concentrations show the same seasonal variation, with a tendency for a maximum concentration during summer months. An inverse relationship, was generally observed, between the 7Be, 210Pb, 40K and 137Cs concentrations and weekly rainfall, indicating washout of the atmospheric aerosol that carries these radionuclides

49

Artificial Intelligence based Solver for Governing Model of Radioactivity Cooling, Self-gravitating Clouds and Clusters of Galaxies  

OpenAIRE

In this study, a reliable alternate platform is developed based on artificial neural network optimized with soft computing technique for a non-linear singular system that can model complex physical phenomenas of the nature like radioactivity cooling, self-gravitating clouds and clusters of galaxies. The trial solution is mathematically represented by feed-forward neural network. A cost function is defined in an unsupervised manner that is optimized by a probabilistic meta-heuristic global sea...

Junaid Ali Khan; Muhammad Asif Zahoor Raja

2013-01-01

50

Emanations and 'induced' radioactivity: from mystery to (mis)use  

International Nuclear Information System (INIS)

The natural Rn isotopes were discovered within the period 1899-1902 and at that time referred to as emanations because they came out (emanated) of sources/materials containing actinium, thorium and radium, respectively. The (somewhat mysterious) emanations appeared to disintegrate into radioactive decay products which by depositing at solid surfaces gave rise to 'induced' radioactivity i.e. radioactive substances with various half-lives. Following the discovery of the emanations the volume of the research involving them and their disintegration products grew steeply. The identity of a number of these radioactive products was soon established. Radium emanation was soon used as a source of RaD (210Pb) to be applied as an 'indicator' (radiotracer) for lead in a study on the solubility of lead sulphide and lead chromate. Moreover, radium and its emanation were introduced into the medical practice. Inhaling radon and drinking radon-containing water became an accepted medicinal use (or misuse?) of that gas. Shortly after the turn of the century, the healing (?) action of natural springs (spas) was attributed to their radium emanation, i.e. radon. Bathing in radioactive spring water and drinking it became very popular. Even today, bathing in radon-containing water is still a common medical treatment in Jachymov, Czech Republic. (author)

51

Studying the induced radioactivity of a varian clinac 2100C/D accelerator  

International Nuclear Information System (INIS)

Objective: To Study the influences of dose, time, distance and irradiation mode on induced radioactivity by measuring a Varian Clinac 2100C/D accelerator. Methods: The induced radioactivity was measured in different dose, time, distance and irradiation mode by using of 450P model dosemeter. The results was analysed. Results: The induced radioactivity is direct ratio with dose, inverse ratio with time and distance. In different irradiation mode, the induced radioactivity is different. Conclusion: The induced radioactivity level of accelerator is related with dose, time, distance and irradiation mode. (authors)

52

Induced radioactivity in patients from betatron irradiation  

International Nuclear Information System (INIS)

The ability to reconstruct the distribution of dose delivered throughout the treatment volume after each therapy fraction offers a mechanism for quality control. The activity within the irradiated volume in two pelvic irradiations showed initial rates of 120 to 285 detected events per minute. The activity detected 2 to 25 cm from the edge of the irradiated volume was 0 to 12 coincidences per minute. The average ratio of event rate outside the treatment volume to the rate within the volume, was 0.2 for these patients. In a fourth patient, an anterior pelvic field showed the following results after patient repositioning. A component with half-life of two minutes (15O) was evident with initial activity of 2.7 plus or minus 0.5 x 103 counts per minute, and a component with half-life of 20.4 minutes (11C) was determined with initial activity of 4.7 plus or minus 0.6 x 102 counts per minute. In experiments with rats, only in organs where blood contents were comparable in mass to the parenchyma, were large fractions of the induced activity transported from the radiation site. Biological transport appeared to the major source of background, and could constitute a significant correction in the computation of dose distribution from the activity distribution imaged by the positron camera. (U.K.)

53

Radioactivity Induced by Neutrons: a Thermodynamic Approach to Radiative Capture  

OpenAIRE

When Enrico Fermi discovered slow neutrons, he accounted for their great efficiency in inducing radioactivity by merely mentioning the well-known scattering cross-section between neutrons and protons. He did not refer to capture cross-section, at that early stage. It is put forward that a thermodynamic approach to neutron-proton radiative capture then widely debated might underlie his early accounts. Fermi had already met with a similar approach, and repeatedly used it.

Gregorio, Alberto

2005-01-01

54

Induced radioactivity in Bevatron concrete radiation shielding blocks  

International Nuclear Information System (INIS)

The Bevatron accelerated protons up to 6.2 GeV and heavy ions up to 2.1 GeV/amu. It operated from 1954 to 1993. Radioactivity was induced in some concrete radiation shielding blocks by prompt radiation. Prompt radiation is primarily neutrons and protons that were generated by the Bevatron's primary beam interactions with targets and other materials. The goal was to identify the gamma-ray emitting nuclides (t1/2 > 0.5 yr) that could be present in the concrete blocks and estimate the depth at which the maximum radioactivity presently occurs. It is shown that the majority of radioactivity was produced via thermal neutron capture by trace elements present in concrete. The depth of maximum thermal neutron flux, in theory, corresponds with the depth of maximum induced activity. To estimate the depth at which maximum activity occurs in the concrete blocks, the LAHET Code System was used to calculate the depth of maximum thermal neutron flux. The primary beam interactions that generate the neutrons are also modeled by the LAHET Code System

55

Medical imaging was boosted by the discovery of artificial radioactivity; L'imagerie medicale revelee par la radioactivite  

Energy Technology Data Exchange (ETDEWEB)

This article draws the history of medical imaging since the discovery of artificial radioactivity in 1934. The author reviews the PET (positron emission tomography) and MRI (magnetic resonance imaging) technologies and presents the recent progress in neuro-sciences that have been made possible by using these 2 technologies. Brain imaging has allowed to show: - the impact of emotions on logical mental processes and on mental performances, - the management of memory in the brain of talented quick reckoners, - the degeneration of neurons, and - the link between autism and the presence of structural and functional anomalies in the brain. (A.C.)

Demarthon, F.; Dupuy-Maury, F.; Donnars, O

2002-08-01

56

Artificial sweeteners induce glucose intolerance by altering the gut microbiota.  

Science.gov (United States)

Non-caloric artificial sweeteners (NAS) are among the most widely used food additives worldwide, regularly consumed by lean and obese individuals alike. NAS consumption is considered safe and beneficial owing to their low caloric content, yet supporting scientific data remain sparse and controversial. Here we demonstrate that consumption of commonly used NAS formulations drives the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota. These NAS-mediated deleterious metabolic effects are abrogated by antibiotic treatment, and are fully transferrable to germ-free mice upon faecal transplantation of microbiota configurations from NAS-consuming mice, or of microbiota anaerobically incubated in the presence of NAS. We identify NAS-altered microbial metabolic pathways that are linked to host susceptibility to metabolic disease, and demonstrate similar NAS-induced dysbiosis and glucose intolerance in healthy human subjects. Collectively, our results link NAS consumption, dysbiosis and metabolic abnormalities, thereby calling for a reassessment of massive NAS usage. PMID:25231862

Suez, Jotham; Korem, Tal; Zeevi, David; Zilberman-Schapira, Gili; Thaiss, Christoph A; Maza, Ori; Israeli, David; Zmora, Niv; Gilad, Shlomit; Weinberger, Adina; Kuperman, Yael; Harmelin, Alon; Kolodkin-Gal, Ilana; Shapiro, Hagit; Halpern, Zamir; Segal, Eran; Elinav, Eran

2014-10-01

57

Induced radioactivity of the IHEP proton synchrotron beam extraction equipment  

International Nuclear Information System (INIS)

The measurement results of induced radioactivity of the beam extraction equipment during 1972-1978 are presented. All the values are given to the moment of the accelerator stop. The experimental data permits to predict further possible variations of the induced radioactivity levels of the equipment. Given are the measures required for reduction of the accelerator equipment irradiation, which are the following: 1) compensation of residual distortion of a closed beam orbit in the course of the induction system operation; 2) limitation of the intensity of drop on the internal targets up to the 11 protons per target level over a cycle; 3) putting into operation the program control system for the duration of a current pulse of a linear accelerator to minimize the beam residues at the 70 GeV energy during physical experiments; 4) construction of the system of beam interception and cutting-off to ensure effective energy suppression of uncontrolled beam residues and localization of their radiation effect; 5) extraction of a high-energy beam out of the accelerator during the experiments (e.g., into the neutrino channel for apparatus adjusting) instead of its dropping on the interceptor-target; 6) beam orbit controlling in the case of multiturn injection into the accelerator

58

Induced radioactivity in and around high-energy particle accelerators  

International Nuclear Information System (INIS)

Particle accelerators and their surroundings are locations of residual radioactivity production that is induced by the interaction of high-energy particles with matter. This paper gives an overview of the principles of activation caused at proton accelerators, which are the main machines operated at Conseil Europeen pour la Recherche Nucleaire. It describes the parameters defining radio-nuclide production caused by beam losses. The second part of the paper concentrates on the analytic calculation of activation and the Monte Carlo approach as it is implemented in the FLUKA code. Techniques used to obtain, on the one hand, estimates of radioactivity in Becquerel and, on the other hand, residual dose rates caused by the activated material are discussed. The last part of the paper focuses on experiments that allow for benchmarking FLUKA activation calculations and on simulations used to predict activation in and around high-energy proton machines. In that respect, the paper addresses the residual dose rate that will be induced by proton-proton collisions at an energy of two times 7 TeV in and around the Compact Muon Solenoid (CMS) detector. Besides activation of solid materials, the air activation expected in the CMS cavern caused by this beam operation is also discussed. (authors)

59

Evaluation of induced radioactivity in 10 MeV-electron irradiated spices, (1)  

International Nuclear Information System (INIS)

Black pepper, white pepper, red pepper, ginger and turmeric were irradiated with 10 MeV electrons from a linear accelerator to a dose of 100 kGy and radioactivity was measured in order to estimate induced radioactivity in the irradiated foods. Induced radioactivity could not be detected significantly by ?-ray spectrometry in the irradiated samples except for spiked samples which contain some photonuclear target nuclides in the list of photonuclear reactions which could produce radioactivity below 10 MeV. From the amount of observed radioactivities of short-lived photonuclear products in the spiked samples and calculation of H50 according to ICRP Publication 30, it was concluded that the induced radioactivity and its biological effects in the 10 MeV electron-irradiated natural samples were negligible in comparison with natural radioactivity from 40K contained in the samples. (author)

60

Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy  

Energy Technology Data Exchange (ETDEWEB)

Radioactive iodine ({sup 131}I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, {sup 131}I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the {sup 131}I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of {sup 131}I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of {sup 131}I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with {sup 131}I-induced sialadenitis that is unresponsive to medical treatment.

Jeong, Shin Young; Lee, Jaetae [Kyungpook National University Hospital, Daegu (Korea, Republic of)

2010-06-15

61

Artificial radioactivity in the vicinity of St. Marianna University School of Medicine after the Chernobyl reactor accident  

International Nuclear Information System (INIS)

Following the Chernobyl reactor accident on April 26, 1986, rain water and atomospheric dust were monitored for their possible contamination by artificial radionuclides on the roof of the building of our medical school from April 30 through June 8, 1986. Radiological monitoring was also performed on cabbages obtained from a nearby field, city water, cow's milk produced in Kanagawa Prefecture and human milk obtained from a volunteer living in Kawasaki. Our campus and the nearby area were exposed to 131I from May 2 through 22 by rainfall and from May 1 through 15 by atomospheric dust. In particular, rain water on May 4 and May 5 contained 7600 pCi (282 Bq)/l and 6000 pCi (222 Bq)/l, respectively. The cabbage specimen obtained on May 7 was contaminated by 131I with 808 pCi/kg wet weight, but another specimen obtained on June 6 was not contaminated by any detectable amounts of 131I. No radioactivity was detected in city water during the period monitored. Cow's milk and human milk contained, as a total of ?-radioactivity, 1412 pCi (52 Bq)/l and 915 pCi (34 Bq)/l, respectively. However, parallel determinations on their potassium concentrations revealed that these radioactivities were due entirely to natural 40K. The degree of radiological contamination in and around our campus following the Chernobyl accident was mostly below the action levels above which the governments of several countries involving Japan would take preventive es involving Japan would take preventive measures against possible radiation damages. Although 131I radioactivities contained in the rain water of the first week of May, 1986 significantly exceeded the action level for this radionuclide, their effects on human health were considered negligible and undetectable in the vicinity of our school. (author)

62

The content of natural radioactive elements and artificial radioisotopes in Moldova's soils  

International Nuclear Information System (INIS)

The results of multiyear investigations of natural radionuclide (U-238, Th-232, Ra-226, K-40) and artificial isotopes (Sr-90, Cs-137, I-131) content on soil and plants are presented. Six anomalous polluted areas were detected after Chernobyl nuclear power plant accident. (authors)

63

Levels of natural and artificial radioactivity in sediments in the Eastern Black Sea of Turkey  

International Nuclear Information System (INIS)

Sediments samples collected from the Eastern Black Sea in 1993 from 15 sampling stations of different depths have been analyzed. Natural and artificial radionuclide activity levels in offshore sediment samples from the Eastern Black Sea in Turkey are reported about seven years after the Chernobyl accident. The purpose of this paper is to follow up the earlier study and present results for the distributions of radionuclides in sediments of the Black Sea. (author). 14 refs., 2 figs., 2 tabs

64

Measurement of natural radioactivity and radiation hazards for some natural and artificial building materials available in Romania  

International Nuclear Information System (INIS)

As building materials are known to be the second source regarding high radon concentrations, it is very important to determine the amounts of natural radionuclides from every building material in use. In the present study the most frequently used Romanian natural (sand, gypsum, limestone) and artificial (portland cement, lime, clinker, electrofilter powder, fly ash, cement-lime plaster mortar, cement plaster mortar) building materials were analyzed. The absorbed dose rate and the annual effective dose equivalent rate for people living in dwelling buildings made of these building materials under investigation were also calculated. The analysis was performed with gamma-ray spectrometry, with two hyper-pure germanium detectors. The activity concentrations of natural radionuclides were in the ranges: 5.2-511.8 Bq kg-21 for 226Ra; 0.6-92.6 Bq kg-1 for 232Th and -1 for 40K, respectively. The radium equivalent activity in the fifty-one (51) samples varied from 9 to 603 Bq kg-1. By calculating all the radioactivity indices (Raeq, Hext, I?, Iyr) it was found that all the building materials under investigation can be used to erect dwelling buildings. Except for sample SA6, SA7 and SA11 among the natural building materials and sample SG1, SG2, FAH1, CLM1, CM1 among the artificial building materials that are considered hazardous materials when are used in large quantities. (author)

65

A comparison of artificial saliva and pilocarpine in radiation-induced xerostomia  

International Nuclear Information System (INIS)

Twenty patients with radiation-induced xerostomia were entered into a prospective randomized crossover study comparing a mucin-based artificial saliva (Saliva Orthana) and a mouthwash containing pilocarpine (5 mg three times a day). Overall the patients found that the pilocarpine mouthwash was more effective than the artificial saliva in relieving their symptoms (p = 0.04), and 47 per cent of the patients wanted to continue with this treatment after the study had finished. (author)

66

NATURAL AND ARTIFICIAL RADIOACTIVITY IN BULGARIAN SOILS ALONG THE DANUBE RIVER  

Directory of Open Access Journals (Sweden)

Full Text Available Data from gamma-spectrometry analyses of soils and sediments samples taken along the Danube river is presented in the paper. Results about the content of natural and artifi cial radionuclides like Sr-90 and Cs-137 are discussed. The region around the Kozloduj NPP including its exclusion zone is investigated in more details. Data from the last years is compared with such from former investigations of similar samples from the region. The soil is a natural depot and initial reservoir for spreading of all man-made radionuclides and natural radioactivity. The man-made isotopes with the longest half-life time, like Sr-90 and Cs-137 are mainly investigated. Because of their feature to be bioelements, that is to include themselves in human’s metabolism, they are especially dangerous when their concentrations in the nutritious chain increase. That is why the investigation of these nuclides together with the natural once like uranium, thorium and radium started in 1978 with annual determination of their concentrations in soils collected from the region of “Kozloduj” NPP and some places along the Danube river potentially exposed to radioactive contamination. The aim was to make a picture of the radioecological status of the soils along the Danube river. The period after 1986 is concerned as the accident in Chernobyl’s NPP changed basically the radioactive situation in the country.

I YORDANOVA

2005-07-01

67

Radioactivity  

International Nuclear Information System (INIS)

This pedagogical document presents the origin, effects and uses of radioactivity: where does radioactivity comes from, effects on the body, measurement, protection against radiations, uses in the medical field, in the electric power industry, in the food (ionization, radio-mutagenesis, irradiations) and other industries (radiography, gauges, detectors, irradiations, tracers), and in research activities (dating, preservation of cultural objects). The document ends with some examples of irradiation levels (examples of natural radioactivity, distribution of the various sources of exposure in France). (J.S.)

68

Disturbances of immunological homeostasis induced by radioactive iodine agents  

International Nuclear Information System (INIS)

(CBAxC57B1/6)F1 mice were injected with 125I and 131I-sodium iodide at a dose of 5.74x104 Bq/g. For a long time after such treatment the animals manifested an increased level of spleen cells humoral immune response to a foreign antigen (sheep erythrocytes). The autoreactivity of spleen and lymph node lymphocytes to autologous erythrocytes was also elevated. At the same time the selective migration of 51Cr-labeled spleen lymphocytes to the peripheral lymphoid organs was suppressed. The use of a model system of adoptive cell transfer revealed an increase in the functional activity of cells suppressing a humoral response in mice treated with radiopharmaceuticals. The most pronounced disturbances of immunological reactivity in mice took place 6 mos. after the beginning of the experiment. The results obtained indicated that mechanisms of immune response regulation played a certain role in disturbances of immunological homeostasis induced by radioactive iodine agents

69

Calculation of induced radioactivity in the SAD spallation target  

International Nuclear Information System (INIS)

The Subcritical Assembly in Dubna (SAD) is the installation (in design stage) coupled with existing 660MeV proton accelerator (max beam current 3.2?A). The main characteristics of the subcritical core are: MOX fuel, keff=0.95, fission power 27.6kW, Pb reflector. The SAD spallation target consists of one central and 18 hexagonal (36mm pitch) Pb prisms in 2 concentric layers. The main goal of the calculations, the results of which are presented, is the evaluation of the target total induced radioactivity and of its longitudinal and radial distributions in the target. The time evolution for several working scenarios of the total and long-lived isotopes activity are shown as well. The computational tools applied are the MCNPX2.5e code for high-energy particles and FISPACT for low energy ones. The results obtained with some selected nuclear reaction models in the MCNPX calculations are compared. Calculated results of activities for long-lived isotopes produced by the high energy particles are confronted with the measured ones, obtained in the experiment with bare Pb cylindrical target

70

Scoping estimates of the LDEF satellite induced radioactivity  

Science.gov (United States)

The Long Duration Exposure Facility (LDEF) satellite was recovered after almost six years in space. It was well-instrumented with ionizing radiation dosimeters, including thermoluminescent dosimeters, plastic nuclear track detectors, and a variety of metal foil samples for measuring nuclear activation products. The extensive LDEF radiation measurements provide the type of radiation environments and effects data needed to evaluate and help resolve uncertainties in present radiation models and calculational methods. A calculational program was established to aid in LDEF data interpretation and to utilize LDEF data for assessing the accuracy of current models. A summary of the calculational approach is presented. The purpose of the reported calculations is to obtain a general indication of: (1) the importance of different space radiation sources (trapped, galactic, and albedo protons, and albedo neutrons); (2) the importance of secondary particles; and (3) the spatial dependence of the radiation environments and effects expected within the spacecraft. The calculational method uses the High Energy Transport Code (HETC) to estimate the importance of different sources and secondary particles in terms of fluence, absorbed dose in tissue and silicon, and induced radioactivity as a function of depth in aluminum.

Armstrong, Tony W.; Colborn, B. L.

1990-01-01

71

Host treatments affecting artificial pulmonary metastases; interpretation of loss of radioactivity labelled cells from lungs  

International Nuclear Information System (INIS)

The effect was examined of various host treatments (Corynebacterium parvum injection, immunization, thoracic irradiation, cyclophosphamide injection and anticoagulation) on both lung colony formation and lung clearance of radioactive cells after i.v. injection of tumour cells. The non-immunogenic KHT tumour in C3H/Km mice, and the immunogenic EMT6 tumour in BALB/c/Ka mice were used. For all pretreatments except immunization, the curve loss of radioactivity from the lungs had an initial steep portion representing intravascular death of the tumour cells, followed 1-2 days after tumour-cell injection by a shallow exponential curve which likely represented spontaneous death of tumour cells in the perivascular tissues. Essentially all the injected tumour cells lodged initially in the lungs, and this was unaffected by the different host treatments. Except for specific immunization, cell death in the perivascular tissues was also unaffected by host treatment. However, the survival of the tumour cells during the 24 h after injection was extremely dependent on the particular host pretreatment. The results indicated that host treatments such as C. parvum injection or anticoagulation can markedly affect the number of blood-borne pulmonary metastases, but are only effective if given before the tumour cells arrive in the lung vasculature. (author)

72

Studies of artificial radioactivity in the coastal environment of northern Scotland: a review  

International Nuclear Information System (INIS)

This review brings measurements that have been made over the last 10-15 years of the concentrations of a number of artificial radionuclides in various media in the northern-Scottish coastal environment. The radionuclides include 60Co, 90Sr, 136Cs, 137Cs, 238Pu, 239,240Pu, and 241Am. The media include nearshore and offshore seawater, beach sand and sediments, seaweeds, winkles, spume, deposits on rocks and soils, sheep faeces, and atmospheric deposition. The various radionuclide sources that contribute to the study area are described. Some transfer mechanisms that operate between different media for different radionuclides are discussed, and the radiological significance of the observed radionuclide concentrations is briefly described. (Author)

73

Exchange of radioactive phosphorus 32P between the components of an artificial plant community  

International Nuclear Information System (INIS)

In artificial plant communities (wooden cases with soil) the following plants were grown together for one year: case No. 1: Betula verrucosa Ehrh. (2 specimens) and Carex pilosa Scop.; cases No. 2 and 3: Alnus incana (L.) Mnch., Fraxinus excelsior L., Padus avium Mill., Aegopodium podagraria L., Eupatorium cannabinum L. and others. Into the stalks or stems of one to three plants of every case 32P was introduced. After 3 months all the plants in every case contained radiactive phosphorus. There were great differences in 32P concentration (up to ten-fold) between plants grown in the same case. The concentration of 32P in plants into which it had not been introduced was of the range of 0.1%. (author)

74

Evaluation of artificial radioactivity of the north Western mediterranean sea and evaluation of the sanitary consequences  

International Nuclear Information System (INIS)

The results of radiological measurements of the north west mediterranean observation network outline the level of artificial radionuclides coming from industrial seewages, 106Ru and from atmospheric fall out, 137Cs and sup(239+240)Pu measured on 3 differents types of bioindicators: Mytilus sp., Posidonia oceanica (L.) Del. and demersal fishes as Solea sp., Anguilla anguilla L., Conger conger L. Mytilus sp. is quite a perfect bioindicator of radionuclides contamination but must be linked with fishes sampling which muscles concentrate Cesium at higher level. The sanitary consequences for the waterside population involved by molluscs and fishes ingestion contamined by these 3 radionuclides lead to a fraction (10-5) of the annual dose limit recommanded by the ICRP 26

75

Study on natural and artificial radioactivity of sea water, algae, fish, sea organisms and bottom sediments for the period 1965-1974  

International Nuclear Information System (INIS)

Studies on natural and artificial radioactivity of some fish species, algae, mussels, etc., inhibiting Varna seacoast were carried out in 1965-1974. The samples were radiochemically investigated for total ?-activity, contents of potassium 40, uranium natural, radium 226, strontium 90, and cesium 137. A total of 602 samples are investigated. The results obtained from studying sea water show highest concentration in the village Byala - up to 69,00.10-9 Ci/l, and lowest - in the village of Shabla - up to 32,00.10-9 Ci/l. Radioactivity of some fish varies from 7,10 up to 67,50 pCi (per kg fresh product for strontium 90), and from 14,3 up to 63,50 pCi (per kg fresh product for cesium 137). It is established that scad fish contains the highest radioactivity. Data show that radioactivity in all cases was within the maximum permissible activity level. (author)

76

Natural and artificial radioactivity in milk and dairy products for human consumption (1971-2003)  

International Nuclear Information System (INIS)

Between 1971 and 2003, radioactivity analyses were performed in several dairy products (fresh milk, milk in powder, evaporated milk and in mixed-cereal flours) as part of the program of national environmental radiological surveillance developed by the Department of Environment Control of the Peruvian Nuclear Energy Institute. Analytical assays were performed to evaluate Cs-137, Cs-134, I-131, K-40, Sr-90 (by gamma spectroscopy) and gross beta activity (by beta counting). The obtained values do not represent radiosanitary risk for the population and confirm the presence of K-40 as the main radionuclide in this type of samples. The application of IAEA dosimetric factors allowed calculating intake doses from dairy products in a much lower level than the limits established by international regulation bodies. (author)

77

Evaluation of radioactivity induced by patient-specific devices in proton therapy  

International Nuclear Information System (INIS)

Estimating the radioactivity induced by patient-specific devices installed near the patient skin is important, because patients are directly exposed during the treatment. This study evaluated the radioactivity induced by a brass collimator and a PMMA range compensator in a proton beam and identified the radionuclides produced by nuclear interactions with the proton beam and with the patient-specific devices. The total dose rate depended on the radionuclides, which had short decay times and 1 hour later their activities reach about one-fiftieth of the initial values in the cases of both PMMA and brass. Although the radioactivity induced by proton therapy can affect patients during the radiotherapy, the total radiation dose is much smaller than the prescribed dose for cancer treatment, and the treatment time is very short. Therefore, the radioactivity induced by patient-specific devices should be negligible.

78

Evaluation of radioactivity induced by patient-specific devices in proton therapy  

Energy Technology Data Exchange (ETDEWEB)

Estimating the radioactivity induced by patient-specific devices installed near the patient skin is important, because patients are directly exposed during the treatment. This study evaluated the radioactivity induced by a brass collimator and a PMMA range compensator in a proton beam and identified the radionuclides produced by nuclear interactions with the proton beam and with the patient-specific devices. The total dose rate depended on the radionuclides, which had short decay times and 1 hour later their activities reach about one-fiftieth of the initial values in the cases of both PMMA and brass. Although the radioactivity induced by proton therapy can affect patients during the radiotherapy, the total radiation dose is much smaller than the prescribed dose for cancer treatment, and the treatment time is very short. Therefore, the radioactivity induced by patient-specific devices should be negligible.

Lee, Sang Hoon; Cho, Sung Koo; You, Seung Hoon; Shin, Dong Ho; Park, Sung Yong; Lee, Se Byeong [National Cancer Center, Goyang (Korea, Republic of); Kwak, Jung Won [Asan Medical Center, Seoul (Korea, Republic of); Woo, Jong Kwan [Jeju National University, Jeju (Korea, Republic of); Kim, Dae Hyun [Catholic University, Seoul (Korea, Republic of)

2012-01-15

79

Designing a program to assess potential induced radioactivity in electron beam sterilization of medical devices  

Science.gov (United States)

ISO 11137-1:2006 requires that the potential for induced radioactivity be evaluated for medical devices irradiated with electrons with energy more than 10 MeV. For a manufacturing operation where new devices are being developed, a practical program for making such an evaluation needs to be engrained in the process. A program was developed such that the induced radioactivity evaluation is imbedded in the development of the irradiation process.

Smith, Mark; Logar, John; Vrain, Olivier

2014-12-01

80

Preliminary results on artificial radioactivity and elemental content of samples from Black Sea  

International Nuclear Information System (INIS)

This paper presents results on the concentration of 137Cs, 90Sr, 3H in water samples from 5 locations in NW Black Sea collected in 1999. In sediment samples, 137Cs, and Pu were determined as well as some major and minor elements by X-ray fluorescence. For the surface water samples, 137Cs concentration varied between (26.3 ± 3.4) mBq/l and (41.2 ± 5.6) mBq/l. The concentration of 90Sr was of about 11 mBq/l. The concentration of tritium was low between 24 and 7 T.U. Higher radioactive concentrations in sediment were found in the samples collected from the stations located close to Danube river. For 137Cs values up to (128 ± 6) Bq/kg were found, in agreement to results for NW Black Sea in previous years. The measured concentrations of 239+240Pu, 238Pu radioisotopes are within the range of the values reported in earlier research for the Western Black Sea and Bulgarian Black Sea Coast. (author)

81

Application of naturally occurring isotopes and artificial radioactive tracer for monitoring water flooding in oil field  

International Nuclear Information System (INIS)

Water flooding is an important operation to enhance oil recovery. Water is injected in the oil formation under high pressure through an injection well. Movement of the injected water is needed to be traced to test the performance of water flood, investigate unexpected anomalies in flow and verify suspected geological barriers or flow channels, etc. In the present study environmental isotopes and artificial radiotracer (tritium) were used at Fimkassar Oil Field of Oil and Gas Development Company Limited (OGDCL) where water flooding was started in March 1996 in Sakessar formation to maintain its pressure and enhance the oil recovery. Environmental isotopes: /sup 18/O, /sup 2/H and /sup 3/H, and chloride contents were used to determine the breakthrough/transit time and contribution of fresh injected water. Water samples were collected from the injection well, production well and some other fields for reference indices of Sakessar Formation during June 1998 to August 1999. These samples were analyzed for the /sup 18/O, /sup 2/H and /sup 3/H, and chloride contents. Results show that the water of production well is mixture of fresh water and formation water. The fresh water contribution varied from 67% to 80%, while remaining component was the old recharged formation water. This percentage did not change significantly from the time of break-through till the last sampling which indicates good mixing in the reservoir and absence of any quick channel. The initial breakthrough time was 27 months as the fresh water contributed significantly in the first appearance of water in the production well in June 1998. Tritium tracer, which was injected in November 1998, appeared in the production well after 8 months. It show that breakthrough time decreased with the passage of time. /sup 14/C of inorganic carbon in the water in Chorgali and Sakessar Formations was also analyzed which indicates that the water is at least few thousand years old. (author)

82

Destabilization of artificial biomembrane induced by the penetration of tryptophan  

Energy Technology Data Exchange (ETDEWEB)

The effect of tryptophan on the membrane stability was studied by using three artificial biological membranes including liposome, Langmuir monolayer and solid supported bilayer lipid membrane (s-BLM) as models. All the results indicate that the penetration of tryptophan can destabilize different artificial biological membranes. The diameter of liposome and the leakage of calcein from liposome increased with the increase of tryptophan concentration because the penetration of tryptophan was beneficial for dehydrating the polar head groups of lipids and the formation of fusion intermediates. {pi}-A isotherms of lecithin on the subphase of tryptophan solution further confirm that tryptophan can penetrate into lipid monolayer and reduce the stability of lipid monolayer. When the concentration of tryptophan increased from 0 to 2 x 10{sup -3} mol L{sup -1}, the limiting molecular area of lecithin increased from 110.5 to 138.5 A{sup 2}, but the collapse pressure of the monolayer decreased from 47.6 to 42.3 mN m{sup -1}, indicating the destabilization of lipid monolayer caused by the penetration of tryptophan. The resistance spectra of s-BLM demonstrate that the existence of tryptophan leads to the formation of some defects in s-BLM and the destabilization of s-BLM. The values of electron-transfer resistance and double layer capacitance respectively decreased from 5.765 x 10{sup 6} {Omega} and 3.573 x 10{sup -8} F to 1.391 x 10{sup 6} {Omega} and 3.340 x 10{sup -8} F when the concentration of tryptophan increased from 0 to 2 x 10{sup -3} mol L{sup -1}. Correspondingly, the breakdown voltage of s-BLM decreased from 2.51 to 1.72 V.

Chen Liuhua [Department of Chemistry, Tongji University, Shanghai 200092 (China); Gan Lihua, E-mail: ganlh@tongji.edu.cn [Department of Chemistry, Tongji University, Shanghai 200092 (China); Liu Mingxian; Fan Rong; Xu Zijie; Hao Zhixian; Chen Longwu [Department of Chemistry, Tongji University, Shanghai 200092 (China)

2011-03-15

83

Rainfall and earthquake-induced landslide susceptibility assessment using GIS and Artificial Neural Network  

OpenAIRE

A GIS-based method for the assessment of landslide susceptibility in a selected area of Qingchuan County in China is proposed by using the back-propagation Artificial Neural Network model (ANN). Landslide inventory was derived from field investigation and aerial photo interpretation. 473 landslides occurred before the Wenchuan earthquake (which were thought as rainfall-induced landslides (RIL) in this study), and 885 earthquake-induced landslides (EIL) were recorded into the landslide invento...

Li, Y.; Chen, G.; Tang, C.; Zhou, G.; Zheng, L.

2012-01-01

84

Radioactive contamination of the Shagan river ecosystem components with artificial radionuclides  

International Nuclear Information System (INIS)

Full text: The Shagan river is the only surface waterway on the Semipalatinsk Nuclear Test Site territory. It flows along the eastern boundary of the SNTS and is a left-bank tributary of the Irtysh river. The length of the Shagan riverbed is 275 km with an average slope 0.003, which changes considerably from one part of the riverbed to the other. Within the Balapan testing ground the length of the riverbed is about 50 km, and the slope angle is, on average, 0.002. The watershed area of the left-bank part of the testing ground, where testing wells are located, is about 900 km2. In 2006 during radio-ecological investigations of the SNTS aquatic environment, scientists determined contamination of the Shagan river with radioactive products of nuclear explosions. The main radioactive pollutant is tritium. Maximal tritium concentration in the river waters (40*104 Bq/l) was registered 4.7 km away from the Atomic lake at levels of more than 50 times higher than the maximal permissible level for drinking water. As the distance from the Atomic lake increases, tritium concentration in the Shagan waters considerably decreases, and in the place of its confluence with the Irtysh rivertritium concentration in water becomes 10 Bq/l, which is equal to MPL (maximal permissible level) used for equipment. A complex of scientific investigations including hydrogeological, hydrological and geophysical investigation showed that tritium contamination of the Shagan waterstritium contamination of the Shagan waters is caused by the discharge of contaminated ground waters from the testing ground Balapan. In 2007 additional investigations of the river ecosystem showed that surface waters of the river in addition to tritium contained 90Sr, and bottom sedimentations were contaminated with 60Co, 152Eu, 154Eu and 137Cs. It should be noted that concentration of 90Sr in water reaches the level comparable with intervention level established by NRB-99 (Radiation Safety Norms) for water and food intake. By the character of tritium and 90Sr distribution in water, it was established that the radionuclides have absolutely different sources. Whereas the nature of tritium presence in the water is quite understandable, the source of 90Sr has not been studied yet. To determine the reasons for noticeable increase of the 90Sr concentration in water and the ways of its proliferation into the river, additional investigations are necessary. Possible mechanisms for 90Sr proliferation into the river may be its inflow with ground waters, plane washing off, washing out of 90Sr from contaminated man-made soils of Atomic Lake by atmospheric precipitations. The present-day situation is complicated by active development of pasture cattle breeding and stocking of fodder crops within the bank zone of the shagan river. High tritium concentration, up to 24000 Bq/l, was also registered in the vegetation of the river-bank zone. The presence of tritium was detected in animal products produced by farms situated on the banks of the Shagan river. Tritium concentration in milk samples reaches 5.0*103 Bq/l, which does not exceed maximal permissible values but requires thorough investigation of the problem as tritium concentration in the Shagan waters may vary in a wide range

85

Radioactivity of Tobacco Leaves and Radiation Dose Induced from Smoking  

Directory of Open Access Journals (Sweden)

Full Text Available The radioactivity in tobacco leaves collected from 15 different regions of Greece and before cigarette production was studied in order to find out any association between the root uptake of radionuclides from soil ground by the tobacco plants and the effective dose induced to smokers from cigarette tobacco due to the naturally occurring primordial radionuclides , such as 226Ra and 210Pb of the uranium series and 228Ra of the thorium series and/or man-made radionuclides, such as 137Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the activities of the radioisotopes of radium, 226Ra and 228Ra in the tobacco leaves reflected their origin from the soil by root uptake rather than fertilizers used in the cultivation of tobacco plants. Lead-210 originated from the air and was deposited onto the tobacco leaves and trapped by the trichomes. Potassium-40 in the tobacco leaves was due to root uptake either from soil or from fertilizer. The cesium radioisotopes 137Cs and 134Cs in tobacco leaves were due to root uptake and not due to deposition onto the leaf foliage as they still remained in soil four years after the Chernobyl reactor accident, but were absent from the atmosphere because of the rain washout (precipitation and gravitational settling. The annual effective dose due to inhalation for adults (smokers for 226Ra varied from 42.5 to 178.6 ?Sv/y (average 79.7 ?Sv/y, while for 228Ra from 19.3 to 116.0 ?Sv/y (average 67.1 ?Sv/y and for 210Pb from 47.0 to 134.9 ?Sv/y (average 104.7 ?Sv/y, that is the same order of magnitude for each radionuclide. The sum of the effective doses of the three radionuclides varied from 151.9 to 401.3 ?Sv/y (average 251.5 ?Sv/y. The annual effective dose from 137Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv/y (average 199.3 nSv/y.

Constantin Papastefanou

2009-02-01

86

Radioactivity of tobacco leaves and radiation dose induced from smoking.  

Science.gov (United States)

The radioactivity in tobacco leaves collected from 15 different regions of Greece and before cigarette production was studied in order to find out any association between the root uptake of radionuclides from soil ground by the tobacco plants and the effective dose induced to smokers from cigarette tobacco due to the naturally occurring primordial radionuclides , such as 226Ra and 210Pb of the uranium series and 228Ra of the thorium series and/or man-made radionuclides, such as 137Cs of Chernobyl origin. Gamma-ray spectrometry was applied using Ge planar and coaxial type detectors of high resolution and high efficiency. It was concluded that the activities of the radioisotopes of radium, 226Ra and 228Ra in the tobacco leaves reflected their origin from the soil by root uptake rather than fertilizers used in the cultivation of tobacco plants. Lead-210 originated from the air and was deposited onto the tobacco leaves and trapped by the trichomes. Potassium-40 in the tobacco leaves was due to root uptake either from soil or from fertilizer. The cesium radioisotopes 137Cs and 134Cs in tobacco leaves were due to root uptake and not due to deposition onto the leaf foliage as they still remained in soil four years after the Chernobyl reactor accident, but were absent from the atmosphere because of the rain washout (precipitation) and gravitational settling. The annual effective dose due to inhalation for adults (smokers) for 226Ra varied from 42.5 to 178.6 microSv/y (average 79.7 microSv/y), while for 228Ra from 19.3 to 116.0 microSv/y (average 67.1 microSv/y) and for 210Pb from 47.0 to 134.9 microSv/y (average 104.7 microSv/y), that is the same order of magnitude for each radionuclide. The sum of the effective doses of the three radionuclides varied from 151.9 to 401.3 microSv/y (average 251.5 microSv/y). The annual effective dose from 137Cs of Chernobyl origin was three orders of magnitude lower as it varied from 70.4 to 410.4 nSv/y (average 199.3 nSv/y). PMID:19440399

Papastefanou, Constantin

2009-02-01

87

Electromagnetically Induced Transparency Using a Artificial Molecule in Circuit Quantum Electrodynamics  

Directory of Open Access Journals (Sweden)

Full Text Available Electromagnetically induced transparency (EIT having wide applications in quantum optics and nonlinear optics is explored ordinarily in various atomic systems. In this paper we present a theoretical study of EIT using supercon- ducting circuit with a V-type artificial molecule constructed by two Josephson charge qubits coupled each other through a large capacitor. In our theoretical model we make a steady state approximation and obtain the analytical expressions of the complex susceptibility for the artificial system via the density matrix formalism. The complex susceptibility has additional dependence on the qubit parameters and hence can be tuned to a certain extent.

Hai-Chao Li

2013-06-01

88

Observation of the effects of artificially released long half-life radionuclides on the global radioactive contamination background in the Atlantic and its adjoining seas  

International Nuclear Information System (INIS)

In the behaviors of artificial and natural radionuclides in ocean, there is similarity. In the surface seawater in northern Atlantic Ocean, the seasonal variation in the concentration of falling strontium-90 was established, and its empirical formula was given. The review of the measured results of strontium-90, cesium-137 and -134 in North Sea and the former two in southern Baltic Sea indicated that the radioactive contamination in North Sea due to the release of the radioactive materials, which are not regulated in London Convention concerning the sea dumping of wastes, is far higher than the peak in 1963. Also by the exchange of water masses, radioactive materials entered Baltic Sea. The inflow of cesium-137 from North Sea into Baltic Sea in 1979 was over 10 times as much as that from rivers. In the sea area adjoining the strait, however, cesium-137 of high concentration was not observed. (J.P.N.)

89

Products of an Artificially Induced Hydrothermal System at Yucca Mountain  

International Nuclear Information System (INIS)

Studies of mineral deposition in the recent geologic past at Yucca Mountain, Nevada, address competing hypotheses of hydrothermal alteration and deposition from percolating groundwater. The secondary minerals being studied are calcite-opal deposits in fractures and lithophysal cavities of ash-flow tuffs exposed in the Exploratory Studies Facility (ESF), a 7.7-km tunnel excavated by the Yucca Mountain Site Characterization Project within Yucca Mountain. An underground field test in the ESF provided information about the minerals deposited by a short-lived artificial hydrothermal system and an opportunity for comparison of test products with the natural secondary minerals. The heating phase lasted nine months, followed by a nine-month cooling period. Natural pore fluids were the only source of water during the thermal test. Condensation and reflux of water driven away from the heater produced fluid flow in certain fractures and intersecting boreholes. The mineralogic products of the thermal test are calcite-gypsum aggregates of less than 4-micrometer crystals and amorphous silica as glassy scale less than 0.2 mm thick and as mounds of tubules with diameters less than 0.7 micrometers. The minute crystal sizes of calcite and gypsum from the field test are very different from the predominantly coarser calcite crystals (up to cm scale) in natural secondary-mineral deposits at the site. The complex micrometer-scale textures of the amorphous silica differ from the simple forms of opal spherules and coatings in the natural deposits, even though some natural spherules are as small as 1 micrometer. These differences suggest that the natural minerals, especially if they were of hydrothermal origin, may have developed coarser or simpler forms during subsequent episodes of dissolution and redeposition. The presence of gypsum among the test products and its absence from the natural secondary-mineral assemblage may indicate a higher degree of evaporation during the test than during the deposition of natural calcite-opal deposits

90

Inhibition of artificially induced cough in man by bronchodilators.  

OpenAIRE

1. The antitussive properties of bronchodilators were evaluated in a total of 47 normal volunteers. 2. Cough was induced by inhalation of ultrasonically nebulized solutions of distilled water and hypotonic saline. 3. Inhaled fenoterol hydrobromide (360 micrograms; 20 volunteers) and inhaled ipratropium bromide (72 micrograms; 14 volunteers) both significantly reduced couch compared with placebo (P less than 0.01). Oral salbutamol sulphate (4 mg; 11 volunteers) and oral pirenzepine hydrochlori...

Lowry, R.; Higenbottam, T.; Johnson, T.; Godden, D.

1987-01-01

91

A decade of assessment of the natural and artificial radioactivity in feedstuff and food commodities imported and exported by Brazil  

International Nuclear Information System (INIS)

Full text: Natural and artificial radionuclides in feedstuff with concentration levels surpassing the brazilian (CNEN-NN 3.05, January 2005) and international (IAEA 115 Safety Series, 1996 and Codex Alimentarius, 2006) limits are harmless to the human health and an effective control is needed in order to only allow consumption of products presenting radiation levels below limits. Since 1988, after the Chernobyl accident, the Environmental Radiometric Laboratory at the Nuclear and Energy Research Institute, IPEN-CNEN/SP (Instituto de Pesquisas Energeticas e Nucleares), performs, on a regular basis, analysis of potassium-40, cesium-134 and cesium-137 concentrations in feedstuff and food commodities imported and exported by Brazil. The present work covers mostly a decade of results, from 1996 to 2007, assessed from the measurements of almost 2600 samples. The imported Belgium and the exported ones are originated from 14 Brazilian States and 111 regions. Nearly 90 different kinds of feedstuff and food commodities were measured, including condensed milk, milk powder, soy beans, sugar, raw coffee beans, etc. All samples were analyzed by high resolution gamma-spectrometry and the results, compared with brazilian and international limits, released as a technical report. The radioactivity present in all analyzed products was within the international limits, allowing to conclude that consumption of such goods offers no health risk derived from radiation. Potential relationships between the type and the origin of the products exported and imported by Brazil and the radionuclides concentrations are also approached. Finally, all results will contribute to the establishment of a radiometric database for the radionuclides concentrations in the feedstuff and food commodities produced in Brazil. (author)

92

Radioactivity in spruces  

International Nuclear Information System (INIS)

Some specimens of spruces have been examined by gamma spectroscopy for their amount of natural and induced radioactivity. Besides the natural radionuclides K-40 and Be-7, several gamma-ray emitters of the natural decay chains have been detected, and Cs-137. The activity concentration of the latter, artificial radionuclide, has been found to be very low in comparison with the concentration of all the natural gamma emitters measured. (orig./PW)

93

Studies of muon-induced radioactivity at NuMI  

CERN Document Server

The JASMIN Collaboration has studied the production of radionuclides by muons in the muon alcoves of the NuMI beamline at Fermilab. Samples of aluminum and copper are exposed to the muon field and counted on HpGe detectors when removed to determine their content of radioactive isotopes. We compare the results to MARS simulations and discuss the radiological implications for neutrino factories and muon colliders.

Boehnlein, David J

2012-01-01

94

Evaluation of induced radioactivity in structural material of Toshiba Training Reactor 'TTR1'  

International Nuclear Information System (INIS)

A decommissioning programme for the Toshiba Training Reactor (TTR1), a swimming pool type reactor used for reactor physics experiments and material irradiation, was started in August 2001. As a part of the programme, induced radioactivity in structural material was evaluated using neutron flux data obtained with the three-dimensional Sn code TORT. Induced activity was calculated with the isotope generation code ORIGEN-79 using activation cross section data created from multi-group library based on JENDL-3. The obtained results for radioactivities such as 60Co, 65Zn, 54Mn and 152Eu were compared with measured ones, and the present calculational method was confirmed to have enough accuracy. (authors)

95

Measuring of induced radioactivity of the HE megatile on IREN at JINR.  

CERN Document Server

Results of measurement of the induced radioactivity caused by neutrons for a segment of a multi sectional scintillation detector (megatile) are presented. Two endcap sampling calorimeters (HE) are parts of the hadron calorimeter (HCAL) of experimental setup CMS. Each HE consists of 648 megatiles. Irradiation of a section of the megatile by neutrons has been performed as neutron activation is the main source of induced radioactivity. Irradiation of a segment of the megatile was carried out on IREN - the JINR neutron source facility. The HE will be accessible to humans after a suitable period of cool down.

Afanasiev, Sergey; Borzakov, S.B; Golutvin, Igor; Igamkulov, Z.A; Malakhov, Alexander; Moisenz, Petr; Pogodaev, G.N; Pyataev, V.G; Sedyshev, P.V; Shvetsov, V.N; Smirnov, Vitaly

2014-01-01

96

Measurement of radioactivity induced by GeV-protons and spallation neutrons using AGS accelerator  

International Nuclear Information System (INIS)

Measurement of radioactivity induced by high-energy protons with energy of 2.83 and 24 GeV and spallation neutrons produced by bombarding a mercury target with the high-energy protons were performed by using the AGS (Alternative Gradient Synchrotron) accelerator at Brookhaven National Laboratory. The samples of boron, carbon, aluminum, iron, copper, niobium, mercury-oxide, lead, bismuth, acrylic resin, SS-316, Inconel-625 and Inconel-718 were irradiated around the mercury target. After the irradiation, the radioactivity of each sample was measured by using HPGe detectors at the cooling time between 2 h and 200 d. In the processing of the measured ?-ray spectra, more than 90 radioactive nucleus were identified, and the radioactivity production data were obtained. This report gives the experimental procedure, the data processing and the experimental results. (author)

97

Exploring thermally induced states in square artificial spin-ice arrays  

International Nuclear Information System (INIS)

We present a methodology to explore experimentally the formation of thermally induced long-range ground-state ordering in artificial spin-ice systems. Our novel approach is based on the thermalization from a square artificial spin-ice array of elongated ferromagnetic nanoislands made of a FeNi alloy characterized by a Curie temperature about 100 K lower than that of Permalloy (Ni81Fe19), which is commonly used for this kind of investigation. The decrease in M(T) when the sample is heated close to its Curie temperature reduces the shape anisotropy barrier of each island and allows us to bring the artificial spin-ice pattern above the blocking temperature of the islands, thus ‘melting’ the spin-ice system, without damaging the sample. The magnetization configuration resulting from the thermal excitation of the islands and the frustrated dipolar interactions among them can be then imaged by magnetic force microscopy or any other kind of magnetic microscopy imaging after cooling down the sample back to room temperature. This thermally induced melting–freezing protocol can be repeated as many times as desired on the same sample and the heating and cooling parameters (max T, heating and cooling rates, number of cycles, application of external fields) varied at will. Thereby, the approach proposed here opens up a pathway to the systematic experimental study of thermally induced frozen states in artificial spin-ice systems, which have been the subjce systems, which have been the subject of many recent theoretical studies due to their interesting physical properties but, because of the difficulties in obtaining them in real samples and in a controlled manner, remain experimentally an almost completely unexplored terrain. (paper)

98

IRACM : A code system to calculate induced radioactivity produced by ions and neutrons  

International Nuclear Information System (INIS)

It is essential to estimate of radioactivity induced in accelerator components and samples bombarded by energetic ion beams and the secondary neutrons of high-energy accelerator facilities in order to reduce the amount of radioactive wastes and to minimize radiation exposure to personnel. A computer code system IRACM has been developed to estimate product nuclides and induced radioactivity in various radiation environments of accelerator facilities. Nuclide transmutation with incident particles of neutron, proton, deuteron, alpha, 12C, 14N, 16O, 20Ne and 40Ar can be computed for arbitrary multi-layer target system in a one-dimensional geometry. The code system consists of calculation modules and libraries including activation cross sections, decay data and photon emission data. The system can be executed in both FACOM-M780 mainframe and DEC workstations. (author)

99

Radioactivity induced by cosmic radiation in the Saint Severin meteorite  

International Nuclear Information System (INIS)

On 27 June 1966 at 2.40 p.m. G.M.T., a stone meteorite (chondrite) fell close to Saint Severin (Charente, France). Eight fragments were found with respective masses of 113 kg, 57.6 kg, 46 kg, 27.2 kg, 19.9 kg, 5.2 kg, 2.7 kg and 0.35 kg. They are distributed with good approximation along a straight line in the east-west direction over a distance of about 10 km. Low-activity gamma spectrometry measurements (NaI(Tl) scintillator 10 cm x 8 cm) were commenced on the 113 kg fragment only 60 hours after it fell, allowing the detection of short-lived radioactive cosmonuclides. The following nuclides were found: 24Na, 5'2Mn, 48V, 56Co + 58Co, 46Sc, 54Mn, 22Na, 60Co, 26A1 and 40K. (author)

100

Radioactivity. Centenary of radioactivity discovery  

International Nuclear Information System (INIS)

This small booklet was edited for the occasion of the exhibitions of the celebration of the centenary of radioactivity discovery which took place in various locations in France from 1996 to 1998. It recalls some basic knowledge concerning radioactivity and its applications: history of discovery, atoms and isotopes, radiations, measurement of ionizing radiations, natural and artificial radioactivity, isotope dating and labelling, radiotherapy, nuclear power and reactors, fission and fusion, nuclear wastes, dosimetry, effects and radioprotection. (J.S.)

101

Monte-Carlo study of induced radioactivity in probe for low-energy proton beam  

Science.gov (United States)

Induced radionuclides generated from the probe which is bombarded by proton beam will turn the detector into a typical external irradiation radiation source. Thus, it is beneficial for developing radiation protection to calculate the types and the activities of radionuclides. Here we applied both a theoretical analysis and a Monte-Carlo method to compute the induced radioactivity in a copper probe irradiated by proton beam. Various kinds of radionuclides saturation activity obtained by these two different methods were compared. The comparisons of the results cast by the two methods show the similar saturation activities for 63Zn and 65Zn. However, the Monte-Carlo method conducted by the software FLUKA is able to provide a more complete consideration on nuclear reaction, and to calculate both the direct and indirect radioactivity under different irradiation time. Furthermore, by employing the FLUKA Monte-Carlo program, the induced radioactivity of three types of probe materials (Cu, Ta and W) under low-energy (below 20 MeV) proton beam irradiated were also separately simulated and tantalum is considered as the best material for low-energy proton interceptive diagnostics probe due to the higher energy threshold of nuclear reaction and the lower radioactivity.

Tao, Wang; Kaizhi, Zhang; Qing, Li; Jidong, Long; Xiaozhong, He; Xiaobing, Jing

2011-07-01

102

Study on radioactivity induced by various patient-specific devices in proton therapy  

Energy Technology Data Exchange (ETDEWEB)

It is important to estimate the radioactivities induced by the patient-specific devices installed near the patient skin because it was directly expose the patient during the treatment. This study evaluated the radioactivities induced by the brass collimator and PMMA range compensator in the proton beam, and identified the radionuclide produced by the nuclear interactions of the proton beam with the patient specific devices. When the radiation dose was evaluated at the highest energy region, the exposure of patients by the radioactivities in the patient-specific devices was usually very low when compared to the dose limit in Korea. PMMA, which is mainly composed of oxygen and carbon, is used to fabricate the range compensators. The aperture of the used brass, which is mainly composed of zinc and copper, determines the boundary between the tumor and normal tissue in the body of the patient. Furthermore, these materials are widely used for phantoms and apertures. The radioactivities induced in brass and PMMA after the irradiation of proton beam was evaluated. The radionuclides in brass and PMMA produced by protons and neutrons were the major cause of radiation exposure for patients in proton therapy. In both case of PMMA and brass, 1 hour later their activities reach about 2% of the initial values. The amount of radiation dose is small due to the short treatment time, and the radiation exposure of patients is negligible when compared to the total dose to the patient

Lee, Sang Hoon

2012-02-15

103

Five new eudesmane-type sesquiterpenoids from Chinese agarwood induced by artificial holing.  

Science.gov (United States)

Five new eudesmane-type sesquiterpenoids (1-5), along with six known ones (6-11), were isolated from Chinese agarwood induced by artificial holing originating from Aquilaria sinensis (Lour.) Gilg (Thymelaeaceae). The structures of the new sesquiterpenoids were established by spectroscopic methods including UV, IR, MS, 1D, and 2D NMR. Compounds 1, 3, 6 and 7 exhibited antibacterial activities against both Staphylococcus aureus and Ralstonia solanacearum, and compound 5 only showed an inhibitory activity towards S. aureus. Compounds 1, 6, 7 and 10 showed weak acetylcholinesterase inhibitory activity. PMID:25447164

Li, Wei; Cai, Cai-Hong; Guo, Zhi-Kai; Wang, Hao; Zuo, Wen-Jian; Dong, Wen-Hua; Mei, Wen-Li; Dai, Hao-Fu

2015-01-01

104

Differences in gene expression between natural and artificially induced leaf senescence in barley.  

Science.gov (United States)

Senescence is the last step of leaf development in the life span of an annual plant. Senescence can be induced prematurely by treating leaf tissues with jasmonic acid methyl ester (methyl jasmonate, MeJA). During both senescence programmes, drastic changes occur at the biochemical, cellular and ultra-structural levels that were compared here for primary leaves of barley (Hordeum vulgare L.). Our findings indicate that both types of senescence are similar with respect to the morphological changes including the loss of chlorophyll, disintegration of thylakoids, and formation of plastoglobules. However, the time elapsed for reaching senescence completion was different and ranged from 7 to 8 days for artificially senescing, MeJA-treated plants to 7-8 weeks for naturally senescing plants. Pulse-labelling studies along with RNA and protein gel blot analyses showed differential changes in the expression of both plastid and nuclear genes coding for photosynthetic proteins. Several unique messenger products accumulated in naturally and artificially senescing, MeJA-treated leaves. Detailed expression and crosslinking studies revealed that pheophorbide a oxygenase (PAO), a previously implicated key enzyme of chlorophyll breakdown, is most likely not rate-limiting for chlorophyll destruction under both senescence conditions. Metabolite profiling identified differential changes in the composition of carotenoid derivatives and prenyl-lipids to occur in naturally senescing and artificially senescing plants that underscored the differences between both senescence programmes. PMID:25637827

Springer, Armin; Acker, Georg; Bartsch, Sandra; Bauerschmitt, Heike; Reinbothe, Steffen; Reinbothe, Christiane

2015-03-15

105

Induced radioactivity of LDEF materials and structural components  

Science.gov (United States)

We present an overview of the Long Duration Exposure Facility (LDEF) induced activation measurements. The LDEF, which was gravity-gradient stabilized, was exposed to the low Earth orbit (LEO) radiation environment over a 5.8 year period. Retrieved activation samples and structural components from the spacecraft were analyzed with low and ultra-low background HPGe gamma spectrometry at several national facilities. This allowed a very sensitive measurement of long-lived radionuclides produced by proton- and neutron-induced reactions in the time-dependent, non-isotropic LEO environment. A summary of major findings from this study is given that consists of directionally dependent activation, depth profiles, thermal neutron activation, and surface beryllium-7 deposition from the upper atmosphere. We also describe a database of these measurements that has been prepared for use in testing radiation environmental models and spacecraft design.

Harmon, B. A.; Laird, C. E.; Fishman, G. J.; Parnell, T. A.; Camp, D. C.; Frederick, C. E.; Hurley, D. L.; Lindstrom, D. J.; Moss, C. E.; Reedy, R. C.; Reeves, J. H.; Smith, A. R.; Winn, W. G.; Benton, E. V.

1996-01-01

106

Induced radioactivity in tissues caused by high energy protons  

International Nuclear Information System (INIS)

Theoretical and experimental investigations were performed to study the induced activity in biological objects with the identification of nuclides, the definition of their contribution to the absorbed dose and of the levels of internal and external irradiation from activation of ?- and ?-radiation with the local effect of a proton beam at 1000 MeV. Research was conducted using a medical proton beam at 100 MeV on the synchrocyclotron at the Institute of Nuclear Physics, Academy of Sciences of the USSR, Leningrad. Contribution of induced activity does not exceed 0.1 % of the absorbed dose of proton radiation. The level of external irradiation from the fission of ?-active nuclides in the tissue should be taken into account by the staff who are brought into direct contact with an irradiated biological object in the first 30 min after the accelerator is switched off. Eye protection should be specially envisaged

107

Manifestation of the influence of releases of artificial long-lived radionuclides seen against the background of global radioactive contamination of the Atlantic Ocean and related seas  

International Nuclear Information System (INIS)

The authors note an analogy in the behaviour of artificial and natural radionuclides in the ocean. A seasonal tendency is observed in the variations of 90Sr concentrations due to global fall-out in surface waters of the North Atlantic (200N-700N latitude), and an empirical formula is suggested to describe the observed seasonality. The results are given of 90Sr, 137Cs and 134Cs determinations carried out by the authors in the surface waters of the North Sea, and of 90Sr and 137Cs determinations made in surface waters of the southern part of the Baltic Sea. A comparison with data from the literature shows that the release of radioactive materials beyond the norms laid down in the London Dumping Convention of 1952 led to serious contamination of the North Sea, to levels in fact which were considerably in excess of the global radioactive contamination for 1963. Through the normal processes of turnover and interchange of water masses, the resultant radioactive impurities entered the Baltic Sea. In 1979 the influx of 137Cs from the North Sea into the Baltic was ten times greater than the influx through river discharge. However, in surface waters near the straits in the south and south-west part of the Baltic no increased concentration of 137Cs was found in 1979. (author)

108

A radiation-induced breast cancer following artificial pneumothorax therapy for pulmonary tuberculosis  

International Nuclear Information System (INIS)

A case of radiation-induced breast cancer in a woman who had been fluoroscopied repeatedly for control of pneumothorax for pulmonary tuberculosis 35 years before is reported. The breast tissue presumably received about 136 rads or less in three and a half years. In Japan, both prospective and retrospective surveies following multiple fluoroscopies during artificial pneumothorax collaps therapy have failed to show an increase in the risk of subsequent development of primary breast cancer. The dose given to breast tissues in Japanese patients was generally far less than that in the MacKenzie's series. A radiation-induced breast cancer in Japanese literature has not yet been reported. It seems that the lesser doses may explain the reason of this fact. (auth.)

109

Induced radioactivity in air and water at medical accelerators  

International Nuclear Information System (INIS)

Activation of air and water has been evaluated at the 10 and 15 MeV linear electron accelerator facilities. At 15 MeV irradiation, the activity of 10-min-half-life 13N was observed in the case of the air in the glove box. Air and water samples were also bombarded by 250 MeV protons and 400 MeV/u carbon, and the irradiation dose was 10 Gy at the isocenter. Upon the ion-chamber monitoring of the air sampled from the glove box, 15O, 13N, and 11C activities were mainly observed. At the end of proton and carbon irradiation, the activity of the water was found to be about 10 kBq·cm-3 and several kBq·cm-3, respectively. From the decay analysis of the induced activity in water, 15O, 13N, and 11C were detected. (author)

110

Evaluation of induced radioactivity in structural material of Toshiba Training Reactor 'TTR1'.  

Science.gov (United States)

A decommissioning programme for the Toshiba Training Reactor (TTR1), a swimming pool type reactor used for reactor physics experiments and material irradiation, was started in August 2001. As a part of the programme, induced radioactivity in structural material was evaluated using neutron flux data obtained with the three-dimensional Sn code TORT. Induced activity was calculated with the isotope generation code ORIGEN-79 using activation cross section data created from multi-group library based on JENDL-3. The obtained results for radioactivities such as 60Co, 65Zn, 54Mn and 152Eu were compared with measured ones, and the present calculational method was confirmed to have enough accuracy. PMID:16604643

Uematsu, Mikio; Kurosawa, Masahiko; Haruguchi, Yoshiko

2005-01-01

111

Nuclear reactions and subsequent radioactive decays induced by 14-MeV neutrons  

International Nuclear Information System (INIS)

Compilation of the data on nuclear reactions and subsequent radioactive decays induced by 14-MeV neutrons is presented in tabular form for most of isotopes available in nature, including the following: Nuclide (isotopic abundance), type of nuclear reaction, reaction Q-value, reaction product, type of decay, decay Q-value, half life of reaction product, decay product, maximum reaction cross section, neutron energy for maximum cross section, reaction cross section for 14-MeV neutrons, radioactivity induced by irradiation of a neutron flux of 1x1015 n/cm2 sec for 4 months, and reference for the cross section. The mass number dependences of (n,2n), (n,p) and (n,?) reaction cross sections by 14-MeV neutrons are given in figures to show general trends of the cross sections. (auth.)

112

Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling  

International Nuclear Information System (INIS)

Artificial ferrimagnets (AFi) have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment induced magnetic patterning with He ions on a single layer reference electrode of magnetic tunnel junctions is possible. For some applications a combination of ion bombardment induced magnetic patterning and artificial ferrimagnets as a reference electrode is desirable. The effect of ion bombardment induced magnetic patterning on pinned artificial ferrimagnets with a Ru interlayer which is frequently used in magnetic tunnel junctions as well as pinned AFis with a Cu interlayer has been tested. Special attention has been given to the question whether the antiferromagnetic interlayer exchange coupling can withstand the ion dose necessary to turn the exchange bias

113

Application of artificial neural networks on the characterization of radioactive waste drums; Aplicacao de redes neurais artificiais na caracterizacao de tambores de rejeito radioativo  

Energy Technology Data Exchange (ETDEWEB)

The methodology consist of system simulation of drum-detector by Monte Carlo for obtention of counting efficiency. The obtained data were treated and a neural artificial network (RNA) were constructed for evaluation of total activity of drum. For method evaluation measurements were performed in ten position parallel to the drum axis and the results submitted to the RNA. The developed methodology showed to be effective for isotopic characterization of gamma emitter radioactive wastes distributed in a heterogeneous way in a 200 litters drum. The objective of this work as to develop a methodology of analyse for quantification and localization of radionuclides not homogeneous distributed in a 200 liters drum based on the mathematical techniques

Potiens Junior, Ademar Jose; Hiromoto, Goro, E-mail: apotiens@ipen.b, E-mail: hiromoto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-10-26

114

New estimation of La Hague contribution to the artificial radioactivity of Norwegian waters (1992-1995) and Barents Sea (1992-1997)  

International Nuclear Information System (INIS)

A release of 10,000 GBq per month of a conservative radionuclide into the central part of the English Channel gives rise to activities (in Bq m-3) of 6 8-89 at Goury, 50-70 in Cherbourg (5 and 30 km from the waste outlet of La Hague), 25-40 in the Straits of Dover, 4-5 at the entrance of the Norwegian Channel and 1-3 at the entrance of the Barents Sea. Taking account of La Hague releases and transit times of 17 and 36 months, a calculation of the contribution of La Hague to the artificial radioactivity of the entrance to the Norwegian Channel and the Barents Sea is given

115

Environmental radioactivity in Caithness and Sutherland. Pt. 10: Studies of artificial radioactivity in the coastal environment of Northern Scotland: a review  

International Nuclear Information System (INIS)

This review brings together measurements which have been made over the last 10-15 years of the concentrations of a number of artificial radionuclides in various media in the northern Scottish coastal environment. The radionuclides include 60Co, 90Sr, 134Cs, 137Cs, 238Pu, 239,240Pu and 241Am. The media include nearshore and offshore seawater, beach sand and sediments, seaweeds, winkles, spume, deposits on rocks and soils, sheep faeces and atmospheric deposition. The various radionuclide sources which contribute to the study area are described. Some transfer mechanisms which operate between different media for different radionuclides are discussed, and the radiological significance of the observed radionuclide concentrations is briefly described. (UK)

116

Computational Analysis of Artificial Gravity as a Possible Countermeasure to Spaceflight Induced Bone Loss  

Science.gov (United States)

During exploration class missions, such as to asteroids and Mars, astronauts will be exposed to reduced gravity for extended periods. Data has shown that astronauts lose bone mass at a rate of 1% to 2% a month in microgravity, particularly in lower extremities such as the proximal femur. Exercise countermeasures have not completely eliminated bone loss from long duration spaceflight missions, which leaves astronauts susceptible to early onset osteoporosis and greater risk of fracture. Introduction of the Advanced Resistive Exercise Device and other large exercise devices on the International Space Station (ISS), coupled with improved nutrition, has further minimized bone loss. However, unlike the ISS, exploration vehicles will have very limited volume and power available to accommodate such capabilities. Therefore, novel concepts like artificial gravity systems are being explored as a means to provide sufficient load stimulus to the musculoskeletal system to mitigate bone changes that may lead to early onset osteoporosis and increased risk of fracture. Currently, there is minimal data available to drive further research and development efforts to appropriately explore such options. Computational modeling can be leveraged to gain insight on the level of osteoprotection that may be achieved using artificial gravity produced by a spinning spacecraft or centrifuge. With this in mind, NASA's Digital Astronaut Project (DAP) has developed a bone remodeling model that has been validated for predicting volumetric bone mineral density (vBMD) changes of trabecular and cortical bone both for gravitational unloading condition and the equivalent of 1g daily load stimulus. Using this model, it is possible to simulate vBMD changes in trabecular and cortical bone under different gravity conditions. In this presentation, we will discuss our preliminary findings regarding if and how artificial gravity may be used to mitigate spaceflight induced bone loss.

Mulugeta, L.; Werner, C. R.; Pennline, J. A.

2015-01-01

117

De novo generation of satellite DNA-based artificial chromosomes by induced large-scale amplification.  

Science.gov (United States)

Mammalian artificial chromosomes (MACs) are engineered chromosomes with defined genetic content that can function as non-integrating vectors with large carrying capacity and stability. The large carrying capacity allows the engineering of MACs with multiple copies of the same transgene, gene complexes, and to include regulatory elements necessary for the regulated expression of transgene(s). In recent years, different approaches have been explored to generate MACs (Vos Curr Opin Genet Dev 8:351-359, 1998; Danielle et al. Trends Biotech 23:573-583, 2005; Duncan and Hadlaczky Curr Opin Biotech 18:420-424, 2007): (1) the de novo formation by centromere seeding, the "bottom-up" approach, (2) the truncation of natural chromosomes or the modification of naturally occurring minichromosomes, the "top-down" approach, and (3) the in vivo "inductive" approach. Satellite DNA-based artificial chromosomes (SATACs) generated by the in vivo "inductive" method have the potential to become an efficient tool in diverse gene technology applications such as cellular protein manufacturing (Kennard et al. BioPharm Int 20:52-59, 2007; Kennard et al. Biotechnol Bioeng 104:526-539, 2009; Kennard et al. Biotechnol Bioeng 104:540-553, 2009), transgenic animal production (Telenius et al. Chromosome Res 7:3-7, 1999; Co et al. Chromosome Res 8:183-191, 2000; Monteith et al. Methods Mol Biol 240:227-242, 2003), and ultimately a safe vector for gene therapy (Vanderbyl et al. Stem Cells 22:324-333, 2004; Vanderbyl et al. Exp Hematol 33:1470-1476, 2005; Katona et al. Cell. Mol. Life Sci 65:3830-3838, 2008). A detailed protocol for the de novo generation of satellite DNA-based artificial chromosomes (SATACs) via induced large-scale amplification is presented. PMID:21431723

Csonka, Erika

2011-01-01

118

Radiation-induced polymerization of unsaturated phospholipid mixtures for the synthesis of artificial red cells  

Science.gov (United States)

Radiation induced polymerization of phospholipid containing unsaturated acyl chains was applied to the synthesis of artificial red cells. Vesicles of 1,2-bis-(2,4-octadecadienoyl)-phosphatidylcholine (DODPC) and 1-stearoyl-2-(2,4-octadecadienoyl)-phosphatidylcholine (AODPC) were irradiated by 60Co ?-rays to obtain polymerized bilayer structure of these monomers. It was found that the polymerization of unsaturated groups located at 2-acyl chain of DODPC polymerized faster than those of AODPC. The difference was explained by the packed state of these monomers in the bilayer vesicles. The artificial red cell was obtained by irradiating the mixture of DODPC or AODPC with hemoglobin, cholesterol and palmitic acid sodium salt. The integrity of the irradiated hemoglobin in the vesicle was maintained by keeping the suspended solution at low temperature. On the other hand, oxidation of heme part became remarkable when the vesicle was kept at 37°C. The presence of extra hemoglobin outside the vesicle was found useful to prevent this oxidation.

Hosoi, F.; Omichi, H.; Akama, K.; Awai, K.; Endo, S.; Nakano, Y.

1997-08-01

119

DCHAIN-SP 2001: High energy particle induced radioactivity calculation code  

International Nuclear Information System (INIS)

For the purpose of contribution to safety design calculations for induced radioactivities in the JAERI/KEK high-intensity proton accelerator project facilities, the DCHAIN-SP which calculates the high energy particle induced radioactivity has been updated to DCHAIN-SP 2001. The following three items were improved: (1) Fission yield data are included to apply the code to experimental facility design for nuclear transmutation of long-lived radioactive waste where fissionable materials are treated. (2) Activation cross section data below 20 MeV are revised. In particular, attentions are paid to cross section data of materials which have close relation to the facilities, i.e., mercury, lead and bismuth, and to tritium production cross sections which are important in terms of safety of the facilities. (3) User-interface for input/output data is sophisticated to perform calculations more efficiently than that in the previous version. Information needed for use of the code is attached in Appendices; the DCHAIN-SP 2001 manual, the procedures of installation and execution of DCHAIN-SP, and sample problems. (author)

120

DCHAIN-SP 2001: High energy particle induced radioactivity calculation code  

Energy Technology Data Exchange (ETDEWEB)

For the purpose of contribution to safety design calculations for induced radioactivities in the JAERI/KEK high-intensity proton accelerator project facilities, the DCHAIN-SP which calculates the high energy particle induced radioactivity has been updated to DCHAIN-SP 2001. The following three items were improved: (1) Fission yield data are included to apply the code to experimental facility design for nuclear transmutation of long-lived radioactive waste where fissionable materials are treated. (2) Activation cross section data below 20 MeV are revised. In particular, attentions are paid to cross section data of materials which have close relation to the facilities, i.e., mercury, lead and bismuth, and to tritium production cross sections which are important in terms of safety of the facilities. (3) User-interface for input/output data is sophisticated to perform calculations more efficiently than that in the previous version. Information needed for use of the code is attached in Appendices; the DCHAIN-SP 2001 manual, the procedures of installation and execution of DCHAIN-SP, and sample problems. (author)

Kai, Tetsuya; Maekawa, Fujio; Kasugai, Yoshimi; Takada, Hiroshi; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kosako, Kazuaki [Sumitomo Atomic Energy Industries, Ltd., Tokyo (Japan)

2001-03-01

121

Investigation of induced radioactivity in the CERN Large Electron Positron collider for its decommissioning  

International Nuclear Information System (INIS)

The future installation of the Large Hadron Collider in the tunnel formerly housing the Large Electron Positron collider (LEP) required the dismantling of the latter after 11-year operation. As required by the French legislation, an extensive theoretical study was conducted before decommissioning to establish the possible activation paths both in the accelerator and in the four experiments (L3, ALEPH, OPAL and DELPHI) installed around the ring. The aim was to define which areas may contain activated material and which ones would be completely free of activation. The four major sources of activation in LEP, i.e., distributed and localized beam losses, synchrotron radiation and the super-conducting RF cavities, were investigated. Conversion coefficients from unit lost beam power to induced specific activity were established for a number of materials. A similar study was conducted for the four experiments, evaluating the four potential sources of induced radioactivity, namely e+e- annihilation events, two-photon events, e+e- Bhabha scattering events and beam-related radiation, i.e., synchrotron radiation and off-momentum beam particles. Decommissioning started early in 2001 and was completed by February 2002. Every single piece removed from the machine tunnel and experimental areas was double-checked for induced radioactivity, with complementary gamma-spectrometry measurements performed on samples of the various materials. The on samples of the various materials. The measurements have to a large extent confirmed the predictions. The overall intent of this paper is to provide data and computational guidelines for assessing induced radioactivity in high-energy electron accelerators, which could be of use in future decommissioning

122

Induced radioactivities and cross section measurements of the 14 MeV irradiated molybdenum foils  

International Nuclear Information System (INIS)

The radioactivities of 14 MeV neutron irradiated Molybdenum foils have been measured for comparison exercise conducted by the IAEA Nuclear Data Section. The spectra of the characteristic gamma-rays emitted as a result of the induced radioactivity were taken with a Ge(Li) detector and an Intrinsic Germanium detector. The cross sections for the reaction 92Mo(n,np)91mNb, 95Mo(n,p)95Nb and 98Mo(n,?)95Zr have been determined using the information provided by the IAEA on the irradiation time, total fluence and masses of the irradiated foils. The activation cross sections determined from the present measurements have been compared with previous work. (author). 8 refs, figs, 3 tabs

123

Thallium-201 radioactive implant induced x-ray emission scanning of stable iodine distribution in thyroid  

International Nuclear Information System (INIS)

A new method has been developed for imaging the thyroid gland by the use of 201Tl radioactive implant induced X-ray emission (RIXE). The thyroid phantom was made from two cylindrical tubes embedded in plastic neck phantom. Each tube consisted of stable iodine and 201Tl radioactive source in 10 ml water solution. Some photopeaks in the energy range from 20 to 200 keV were scanned along a horizontal axis by the collimated Ge detector with high energy resolution. The distribution on the horizontal axis was obtained for the generated I K?-ray and some primary 201Tl radiations. The 201Tl RIXE scanning can provide information about the distribution of iodine with 201Tl as well as 201Tl distribution in the thyroid gland. The effectiveness of the 201Tl RIXE technique as a thyroid scanning method is discussed. (author)

124

Artificial radioactivity in edible parts of giant clam mollusc from Mururoa atoll from 1967 to 1990. Health physics aspect  

International Nuclear Information System (INIS)

Radionuclides concentration by giant clams is associated with feeding habit. It's also a main food for polynesian atolls inhabitants, elsewhere than Mururoa island because this mollusc is not consumed like all the other fishery products from this atoll lagoon. Nevertheless measurements of ten artificial radionuclides are performed in edible parts of giant clams fished from Mururoa lagoon since the beginning of nuclear tests. The decay of radionuclides concentration is described versus time. To go further on we have computed the dose-equivalent for internal exposure of an eventual giant clams eater. It is estimated that the resulting risk of malignancy is below than 1 per 10 000

125

The use of an experimental device for the determination of the concentration of artificial radioactive aerosols at high altitudes  

International Nuclear Information System (INIS)

By means of measurements with a Geiger counter on january, the 27th, in 1959 at an altitude reaching 65 km approximately, and following comparison with similar measurements made by Gangnes, Jenkins and Van Allen in 1949 at the same geomagnetic latitude (41 deg. North), it is concluded that radioactive aerosols above Southern France tropopause had a concentration less than 100.10-12 curies/m3 at that time. The missile used for this purpose and its performance are quickly described in this paper. (author)

126

Selection and investigation of sites for the disposal of radioactive wastes in hydraulically induced subsurface fractures  

International Nuclear Information System (INIS)

Injection of intermediate-level radioactive wastes (specific activity of less than 6 x 103 ?Ci/mL, consisting mainly of radionuclides, such as strontium and cesium, having half-lives of less than 50 years) mixed with cement into a thick shale formation is a promising and feasible disposal method. Hydraulic fracturing provides openings in the shale to accommodate the wastes. Ion exchange and radionuclide-adsorption materials can be added to the grout during mixing to further increase the radionuclide-retaining capacity of the grout. After solidification of the grout, the injected wastes become an integral part of the shale formation, and therefore the wastes will remain at depth and in place as long as the injection zone is not subjected to erosion and dissolution. Problems concerning safety of the disposal method are (1) the potential for inducing vertical fractures, (2) phase separation during and after the injections, (3) the reliability of methods for determining the orientation of induced fractures, (4) the possibility of triggering earthquakes, and (5) radionuclides being leached and transported by ground water. Theoretical considerations about inducing nearly horizontal bedding-plane fractures in shale are discussed, as are field procedures for site selection, safety, and the monitoring and operation of radioactive waste disposal. Case histories are used as examples to demonstrate the application of the theory and techniques of field operations and techniques of field operations

127

Site selection and investigation for subsurface disposal of radioactive wastes in hydraulically induced fractures  

International Nuclear Information System (INIS)

Injection into a thick shale formation of intermediate-level radioactive wastes (specific activity of less than 6 x 103 ?Ci/ml consisting mainly of radionuclides such as strontium and cesium with half-lives of less than 50 years) mixed with cement is a promising and feasible disposal method. Hydraulic fracturing provides openings in the shale to accommodate the wastes. Ion exchange and radionuclide adsorption materials can be added to the grout during mixing to further increase the radionuclide retaining capacity of the grout. After solidification of the grout, the injected wastes become an integral part of the shale formation and thus the wastes will remain at depth and in place as long as the injection zone is not subjected to erosion or dissolution. Problems concerning safety of the disposal method are: (1) potential of inducing vertical fractures; (2) phase separation during and after injections; (3) reliability of methods for determining orientation of induced fractures; (4) possibility of triggering earthquakes; and (5) radionuclides leaching and transporting by ground water. Waste injections are made in multiple-layer injection stages in an injection well. After the first series of injections are made at the greatest depth, the well is plugged by cement at the injection depth. The depth of the second series of injections is located at a suitable distance above the first injection depth. The repeated use of the injection well distributes the cost of e injection well distributes the cost of construction of injection and monitoring wells over many injections, thereby making hydraulic fracturing and grout injection economically attractive as a method for disposal of radioactive wastes. Theoretical considerations of inducing nearly horizontal bedding-plane fractures in shale and field procedures for site selection, safety, monitoring and operation of radioactive waste disposal are discussed. Case histories are used as examples to demonstrate the theoretical applications and field operations

128

Study of Natural and Artificial Radioactivity of Sinai Soils and Analysis of Uranium in Contaminated Samples by Uranyl Nitrate Solution  

International Nuclear Information System (INIS)

Sinai Peninsula covers an area of approximately 61000 km2 and is separated geographically from Egypt by the Suez canal and the gulf of Suez. It is located in the north east of Egypt, between the arms of the red sea. Twenty eight samples were collected from Rafah at North to EI Naqab at south for measuring the natural radioactivity 238U, 232Th, 40K and also 137Cs as man made radioactivity using HPGe detector and its components. The radium equivalent and the gamma radiation hazard index (I?) were also calculated. Total uranium content for nine samples was determined using laser fluorimetry. The 235U/238U ratio with different concentration of uranyl nitrate solution was also determined by nondestructive gamma assay. The count rate isotopic ratios of 235U/ 238U at different gamma transitions were found to be straight line with increase of uranium concentration from 50 to 900 ppm. The soil samples which were contaminated with different concentrations of uranyl nitrate (1-500 ppm) found that uranium could be detected in these samples at a threshold concentration of 50 ppm

129

High energy proton-induced radioactivity in HgI2 crystals  

International Nuclear Information System (INIS)

Mercuric iodide (HgI2) semiconductor crystals are generating a lot of interest as room temperature solid state detectors for hard X-ray astronomy observations. For these applications one of the most important background sources is the cosmic proton induced radioactivity in the detector material. In order to study this background noise contribution a 1x1x1 cm HgI2 crystal was irradiated with high energy protons. The resulting long-lived unstable isotopes and their production rates have been identified and compared with Monte Carlo simulations. ((orig.))

130

Estimation of induced radioactivity in accelerator driven systems by 250 MeV protons  

International Nuclear Information System (INIS)

In this work we present the data on induced radioactivity generated in bulk lead-bismuth eutectic (LBE) and iron (Fe) targets by 250 MeV, 500 ?A proton beam calculated using cross section data from nuclear reaction codes. For this purpose excitation functions of different radionuclides produced are calculated by the nuclear reaction model codes ALICE91, EMPIRE 2.18 and TALYS-1.0. From our calculation maximum activity was found to be of the order of 107 MBq for 204Bi, 206Bi and 204Pb. Results from ALICE91 and TALYS-1.0 agree well for most of the isotopes. (author)

131

Rainfall and earthquake-induced landslide susceptibility assessment using GIS and Artificial Neural Network  

Directory of Open Access Journals (Sweden)

Full Text Available A GIS-based method for the assessment of landslide susceptibility in a selected area of Qingchuan County in China is proposed by using the back-propagation Artificial Neural Network model (ANN. Landslide inventory was derived from field investigation and aerial photo interpretation. 473 landslides occurred before the Wenchuan earthquake (which were thought as rainfall-induced landslides (RIL in this study, and 885 earthquake-induced landslides (EIL were recorded into the landslide inventory map. To understand the different impacts of rainfall and earthquake on landslide occurrence, we first compared the variations between landslide spatial distribution and conditioning factors. Then, we compared the weight variation of each conditioning factor derived by adjusting ANN structure and factors combination respectively. Last, the weight of each factor derived from the best prediction model was applied to the entire study area to produce landslide susceptibility maps.

Results show that slope gradient has the highest weight for landslide susceptibility mapping for both RIL and EIL. The RIL model built with four different factors (slope gradient, elevation, slope height and distance to the stream shows the best success rate of 93%; the EIL model built with five different factors (slope gradient, elevation, slope height, distance to the stream and distance to the fault has the best success rate of 98%. Furthermore, the EIL data was used to verify the RIL model and the success rate is 92%; the RIL data was used to verify the EIL model and the success rate is 53%.

Y. Li

2012-08-01

132

An analysis of pump-induced artificial ionospheric ion upwelling at EISCAT  

Science.gov (United States)

Ion outflow from the high-latitude ionosphere is a well-known phenomenon and an important source of plasma for the magnetosphere. It is also well known that pumping the ionosphere with high-power high-frequency radio waves causes electron heating. On a few occasions, this has been accompanied by artificially induced ion upwelling. We analyze such a controlled experiment at EISCAT up to 600 km altitude. The pump-enhanced electron temperatures reached up to ˜4000 K above 350 km, and ion upwelling reached up to ˜300 m/s above 500 km altitude. The pump-induced electron pressure gradient can explain the ion velocity below 450 km. Between 450 and 600 km the electron pressure gradient correlates equally with ion acceleration and ion velocity, which represents the transition altitude to free ion acceleration. The electron gas pressure gradient can explain ion upwelling, at least up to 600 km altitude. In addition, such active experiments open the possibility to estimating the F layer ion-neutral collision frequency and neutral density with altitude from ground-based observations.

Kosch, M. J.; Ogawa, Y.; Rietveld, M. T.; Nozawa, S.; Fujii, R.

2010-12-01

133

Laser induced breakdown spectroscopy: Investigation of line profiles, slurries and artificial neural network prediction  

Science.gov (United States)

Laser induced breakdown spectroscopy (LIBS) was tested to examine its applicability to remote and in suit analysis in inaccessible situation. Two types of liquid sample (slurry) prepared for simulating vitrification of liquid hazardous wastes was tested. In situ analysis ability makes the LIBS technique practical for analysis of the slurry samples during vitrification, which is in inaccessible situation. For the first slurry sample, two slurry circulation systems were devised to overcome major technical problems associated with LIBS measurements of slurry samples---namely sedimentation and change in the lens-to-sample distance (L.T.S.D) during measurement. The second slurry sample contained less water and is able to be managed in a small glass container during test. We applied direct analysis of slurry sample filled in glass container. Spectroscopic analysis was performed using two different detection systems: Czerny-Turner and Echelle spectrometer systems. In particular, spectroscopic analysis of data from an echelle spectrometer shows the high efficiency for simultaneously determining physical quantities of all elements of interest. We also evaluate LIBS technique to tin alloy samples for the purpose of quantitative analysis by using Echelle spectrometer system. Unknown samples without information of elemental composition were tested to estimate several sample compositions simultaneously. An artificial neural network, calibration method, and chemical analysis were applied to estimate the elemental concentrations of impurities in tin (Sn) alloy. Key words. Slurry, Laser induced breakdown spectroscopy, Line profile.

Oh, Seong Yong

134

Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling  

International Nuclear Information System (INIS)

Artificial ferrimagnets have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment (IB) induced patterning of the exchange bias coupling of a single layer reference electrode in magnetic tunnel junctions with He ions is possible. For applications as, e.g., special types of magnetic logic, a combination of the IB induced patterning of the exchange bias coupling and the implementation of an artificial ferrimagnet as reference electrode is desirable. Here, investigations for a pinned artificial ferrimagnet with a Ru interlayer, which is frequently used in magnetic tunnel junctions, are presented. It is shown that in this kind of samples the exchange bias can be increased or rotated by IB induced magnetic patterning with 10 keV He ions without a destruction of the antiferromagnetic interlayer exchange coupling. An IrMn/Py/Co/Cu/Co stack turned out to be more sensitive to the influence of IB than the Ru based artificial ferrimagnet

135

Measurement of fertilizers induced radioactivity in tobacco plants and elemental analysis using ICAP–AES  

International Nuclear Information System (INIS)

It is widely accepted that tobacco smoke is the leading cause of lung cancer worldwide. The alpha radioactive content present in tobacco smoke and increasing number of lung cancer cases explain the importance of investigation. The use of different fertilizers may cause alteration in the metabolism of plants causing different response towards uptake of different element and radionuclides. In the present study, the estimation of alpha radioactivity induced by use of different fertilizers in tobacco leaves was made using solid state nuclear track detector (LR-115) to identify the relative presence of radionuclides in the plants. The radon exhalation rates from the tobacco plant were carried out to confirm the presence of radium or emission of radon from plant. The elemental analysis of tobacco plant by inductively coupled argon plasma atomic emission spectrometry provides a way to understand the difference occurred in metabolism caused by the use of fertilizers. The alpha track densities were found to vary with nature of fertilizers added to the soil and an increase was also observed with time. The radon mass exhalation rates in various tobacco plants were found to vary with type of fertilizers used. - Highlights: • The study is related to alpha radioactivity measurements in tobacco plants. • The radon mass exhalation rates in various tobacco plants were also measured. • Study is related to analysis of chemical elements in different fertilized tobacco samples

136

Ability of use of radiation monitoring networks on detection of natural and artificial radioactivity in the environment  

International Nuclear Information System (INIS)

In the paper there are analysed and compared regional and local early warning radiation monitoring systems. The second generation of early warning systems comprises at least one air filter unit in order to enrich airborne radioactivity, in addition to the traditional dose rate measurement. Two possible implementations of these devices are the systems with moving filter band(s) and with static filter(s), respectively. Model systems are compared and evaluated by virtue of their response to two critical cases: the appearance of an instantaneous contaminant originating from the vicinity of the device and the slow bild-up of and a contaminant arriving from a long distance. Structure and components of sampling, data acquisition and data evaluation procedures are compared according to the requirements of early warning systems. (author)

137

Results of concentration measurements of artificial radioactive aerosols in the lower atmosphere; Resultats des mesures de concentration, dans la basse atmosphere, des aerosols radioactifs artificiels  

Energy Technology Data Exchange (ETDEWEB)

This report gives the results of the measurements of artificial gross-{beta}-radioactivity in aerosols in the lower atmosphere; these measurements have been made by the Electronic Physics Service of the Electronic Department, and by the Atmospheric Physics Laboratory of the Paris Science Faculty. The measurements were begun in September 1956 and were continued in an increasing number of stations both in France and in the rest of the world. The present report deals with the period up to the end of august 1961, that is up to the end of the nuclear moratorium. After recalling the constitution and the properties of radioactive aerosols present in the atmosphere, the authors describe the measurement methods, estimate their accuracy and discuss various aspects of the results. (authors) [French] Ce rapport contient les resultats des mesures de radioactivite {beta} globale d'origine artificielle des aerosols dans la basse atmosphere, effectuees conjointement par le Service d'Electronique Physique du Departement d'Electronique et le Laboratoire de Physique de l'Atmosphere de la Faculte des Sciences de Paris. Les mesures ont commence en septembre 1956 et ont ete poursuivies dans un nombre croissant de stations, tant en France que dans le reste du monde. Le present rapport s'arrete a la fin aout 1961, c'est-a-dire au moment de la reprise des essais nucleaires. Apres avoir rappele la constitution et les proprietes des aerosols radioactifs presents dans l'atmosphere, les auteurs indiquent les methodes de mesure utilisees, evaluent leur precision et discutent les differents aspects des resultats de leurs mesures. (auteurs)

Ardouin, B.; Jehanno, C.; Labeyrie, J.; Lambert, G.; Tanaevsky, O.; Vassy, E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

138

Investigation of induced radioactivity in the CERN Large Electron Positron collider for its decommissioning  

CERN Document Server

The future installation of the Large Hadron Collider in the tunnel formerly housing the Large Electron Positron collider (LEP) required the dismantling of the latter after 11-year operation. As required by the French legislation, an extensive theoretical study was conducted before decommissioning to establish the possible activation paths both in the accelerator and in the four experiments (L3, ALEPH, OPAL and DELPHI) installed around the ring. The aim was to define which areas may contain activated material and which ones would be completely free of activation. The four major sources of activation in LEP, i.e., distributed and localized beam losses, synchrotron radiation and the super-conducting RF cavities, were investigated. Conversion coefficients from unit lost beam power to induced specific activity were established for a number of materials. A similar study was conducted for the four experiments, evaluating the four potential sources of induced radioactivity, namely e**+e **- annihilation events, two-p...

Silari, Marco

2004-01-01

139

Benchmark studies of induced radioactivity and remanent dose rates produced in LHC materials  

International Nuclear Information System (INIS)

Samples of materials that will be used for elements of the LHC machine as well as for shielding and construction components were irradiated in the stray radiation field of the CERN-EU high-energy Reference Field facility. The materials included various types of steel, copper, titanium, concrete and marble as well as light materials such as carbon composites and boron nitride. Emphasis was put on an accurate recording of the irradiation conditions, such as irradiation profile and intensity, and on a detailed determination of the elemental composition of the samples. After the irradiation, the specific activity induced in the samples as well as the remanent dose rate were measured at different cooling times ranging from about 20 minutes to two months. Furthermore, the irradiation experiment was simulated using the FLUKA Monte Carlo code and specific activities. In addition, dose rates were calculated. The latter was based on a new method simulating the production of various isotopes and the electromagnetic cascade induced by radioactive decay at a certain cooling time. In general, solid agreement was found, which engenders confidence in the predictive power of the applied codes and tools for the estimation of the radioactive nuclide inventory of the LHC machine as well as the calculation of remanent doses to personnel during interventions. (authors)

140

2-(2-phenylethyl)chromone derivatives from Chinese agarwood induced by artificial holing.  

Science.gov (United States)

Three new 2-(2-phenylethyl)chromone derivatives (1-3), together with thirteen known ones (4-16), were isolated from the EtOAc extract of Chinese agarwood induced by artificial holing, originating from Aquilaria sinensis (Lour.) Gilg (Thymelaeaceae). The chemical structures of the new compounds were identified by spectroscopic techniques (UV, IR, MS, 1D and 2D NMR). Compounds 1, 6, 15 and 16 exhibited inhibitory effects on Staphylococcus aureus, and compounds 15 and 16 showed inhibitory effects on Ralstonia solanacearum. Compounds 1-3, 7, 9, 11, 12, 15 and 16 exhibited acetylcholinesterase inhibitory activity. A possible biogenetic pathway of compounds 1-16 was proposed to show the relationships between diepoxy-tetrahydro-2-(2-phenylethyl)chromones, epoxy-tetrahydro-2-(2-phenylethyl) chromones, tetrahydro-2-(2-phenylethyl)chromones, and 2-(2-phenylethyl)chromones of the flidersia type, the four main types of 2-(2-phenylethyl)chromones found in agarwood, on the basis of their appearances in different stage of agarwood formation. PMID:25068202

Li, Wei; Cai, Cai-Hong; Dong, Wen-Hua; Guo, Zhi-Kai; Wang, Hao; Mei, Wen-Li; Dai, Hao-Fu

2014-10-01

141

Artificial radioactivity in the lower Rhone river. Consequences of floods on activity levels and flow toward the mediterranean  

International Nuclear Information System (INIS)

Despite analytical strategies that today measure ultra-trace levels (i.e., -5 Bq.L-1) of artificial radionuclides, gamma spectrometry of Rhone River samples taken downstream from the nuclear installations located along the Rhone valley regularly detects only 137Cs, 60Co and 241Am. Since dismantlement of the Marcoule-COGEMA reprocessing plant began in 1997, lists of radionuclides in its effluent include 51Cr, 54Mn, 63Ni, 110mAg and 65Zn, released however at levels 10 to 1,000-fold lower than those of 137Cs or 60Co. Today Marcoule effluent is no longer the principal source of 137Cs in the Rhone River basin, as it was in the 1990's. Significant quantities of 137Cs now come from the Rhone watershed itself, from the drainage of soils exposed to atmospheric fallout from the past nuclear tests and from the accident at Chernobyl, and second, from remobilization of previously formed sediment. Our recent research shows that flood events may generate an increase of more than two orders of magnitude in 137Cs activity in downstream Rhone water, because of the input of contaminated particles from both watershed erosion and sediment remobilization. Flood events also generate the flow of high levels of particulate and associated contaminants towards the Mediterranean Sea. Of the 173±22 GBq of 137Cs transfere 173±22 GBq of 137Cs transferred from the Rhone to the Mediterranean from August 2002 through August 2003, 111±9 GBq went during two floods in September and November 2002: 60% of the annual transfer took place in only 15 days and included almost ten times as much 137Cs activity as is released annually by the reprocessing plant today. The contribution to these flows of re-mobilized Rhone basin sediment inventories contaminated over the past 40 years is under study today. (authors)

142

Artificial Abelian gauge potentials induced by dipole-dipole interactions between Rydberg atoms  

Science.gov (United States)

We analyze the influence of dipole-dipole interactions between Rydberg atoms on the generation of Abelian artificial gauge potentials and fields. When two Rydberg atoms are driven by a uniform laser field, we show that the combined atom-atom and atom-field interactions give rise to nonuniform, artificial gauge potentials. We identify the mechanism responsible for the emergence of these gauge potentials. Analytical expressions for the latter indicate that the strongest artificial magnetic fields are reached in the regime intermediate between the dipole blockade regime and the regime in which the atoms are sufficiently far apart such that atom-light interaction dominates over atom-atom interactions. We discuss the differences and similarities of artificial gauge fields originating from resonant dipole-dipole and van der Waals interactions. We also give an estimation of experimentally attainable artificial magnetic fields resulting from this mechanism and we discuss their detection through the deflection of the atomic motion.

Cesa, A.; Martin, J.

2013-12-01

143

Study of the radioactivity induced in air by a 15-MeV proton beam  

International Nuclear Information System (INIS)

Radioactivity induced by a 15-MeV proton beam extracted into air was studied at the beam transport line of the 18-MeV cyclotron at the Bern University Hospital (Inselspital). The produced radioactivity was calculated and measured by means of proportional counters located at the main exhaust of the laboratory. These devices were designed for precise assessment of air contamination for radiation protection purposes. The main produced isotopes were 11C, 13N and 14O. Both measurements and calculations correspond to two different irradiation conditions. In the former, protons were allowed to travel for their full range in air. In the latter, they were stopped at the distance of 1.5 m by a beam dump. Radioactivity was measured continuously in the exhausted air starting from 2 min after the end of irradiation. For this reason, the short-lived 14O isotope gave a negligible contribution to the measured activity. Good agreement was found between the measurements and the calculations within the estimated uncertainties. Currents in the range of 120-370 nA were extracted in air for 10-30 s producing activities of 9-22 MBq of 11C and 13N. The total activities for 11C and 13N per beam current and irradiation time for the former and the latter irradiation conditions were measured to be (3.60 ± 0.48)x 10-3 MBq (nA s)-1 and (2.89 ± 0.37)x 10-3 MBq (nA s)-1, respectively (authors)

144

Radioactive Ion Beam Production by Fast-Neutron-Induced Fission in Actinide Targets at EURISOL  

CERN Document Server

The European Isotope Separation On-Line Radioactive Ion Beam Facility (EURISOL) is set to be the 'next-generation' European Isotope Separation On-Line (ISOL) Radioactive Ion Beam (RIB) facility. It will extend and amplify current research on nuclear physics, nuclear astrophysics and fundamental interactions beyond the year 2010. In EURISOL, the production of high-intensity RIBs of specific neutron-rich isotopes is obtained by inducing fission in large-mass actinide targets. In our contribution, the use of uranium targets is shown to be advantageous to other materials, such as thorium. Therefore, in order to produce fissions in U-238 and reduce the plutonium inventory, a fast neutron energy spectrum is necessary. The large beam power required to achieve these RIB levels requires the use of a liquid proton-to-neutron converter. This article details the design parameters of the converter, with special attention to the coupled neutronics of the liquid converter and fission target. Calculations performed with the ...

Herrera-Martínez, Adonai

145

A Facility for Studying Radiative Capture Reactions Induced with Radioactive Beams at ISAC  

Science.gov (United States)

The measurement of low energy fusion reactions of importance to nuclear astrophysics scenarios are a prime objective of the physics program of the new ISAC facility, located at TRIUMF in Vancouver, Canada. Intense radioactive beams of 19Ne, 14,15O, 20,21Na, 17,18F and other low Z species with energies in the range of 0.15 to 1.5 MeV/mass unit will be available to measure cross sections and resonance strengths of alpha and proton induced reactions. An important component of the experimental configuration will be a new Reaction Products Detection Facility (RPDF) consisting of a windowless gas target, surrounded by a gamma array, while the recoils are separated from the intense radioactive beam using a Recoil Mass Spectrometer (RMS). The RMS will be based on a Wien filter. The recoiling reaction products will then be detected using either a Si ?-strip array or a gas filled detector. Using these devices along with coincidence requirements and time of flight conditions a background reduction factor of the order of 10+15 is the present goal.

D'Auria, J. M.; Buchmann, L.; Hutcheon, D.; Lipnik, P.; Hunter, D.; Rogers, J.; Helmer, R.; Giesen, U.; Olin, A.; Bricault, P.

1997-02-01

146

Radiological considerations on multi-MW targets Part I Induced radioactivity  

CERN Document Server

CERN is designing a Superconducting Proton Linac (SPL) to provide a 2.2GeV, 4MW proton beam to feed facilities like, for example, a future Neutrino Factory or a Neutrino SuperBeam. The material activation in such facilities is an important aspect that has to be taken into account at an early design stage. In particular, the choice of the target has consequences on the induced radioactivity and dose rates in the target itself and in its surroundings. In the present work, the radiological aspects of a stationary target made up of small tantalum pellets are compared to those of a free-surface jet of mercury. An estimation of the hadronic inelastic interactions and the production of residual nuclei in the target, the magnetic horn, the decay tunnel, the surrounding rock and a downstream dump were performed for both targets by the Monte Carlo hadronic cascade code FLUKA. The aim was to assess the dose equivalent rate to be expected during maintenance work and to evaluate the amount of residual radioactivity, which...

Agosteo, S; Silari, M; 10.1016/j.nima.2005.02.018

2005-01-01

147

A study of assessment on site-choosing of NPPs about human induced outside external artificial events based on multiple objective fuzzy optimal selections  

International Nuclear Information System (INIS)

According to 'AD101/04-Siting of NPPs on Human Induced Outside Artificial External Events', the article evaluates the plane air crash, explosion, release of dangerous liquid quantitatively, then get several site of NPP compared, in advantage of multiple objective fuzzy optimal selection, come to a decision about the sorting of superiority of site from the standpoint of outside artificial human induced events. (authors)

148

Measurement of induced radioactivity in a spallation neutron field of a mercury target for GeV-proton bombardment  

International Nuclear Information System (INIS)

An integral experiment on radioactivity induced in spallation neutron fields was carried out under the ASTE (AGS-Spallation Target Experiment) collaboration using AGS (Alternative Gradient Synchrotron) at BNL (Brookhaven National Laboratory). The spallation neutrons were produced by bombarding a mercury target with protons of 1.6, 12 and 24 GeV. The number of protons was 3 - 4 x 1013 for each irradiation. The irradiated materials were titanium, nickel, cobalt, yttrium, and bismuth, and placed on the cylindrical surface of the mercury target at the distance of 15 - 16 cm from the beam-incident-surface of the target. Disintegration rates of induced radioactivities were measured at several cooling-time ranging from hours to months. The principal nuclides contributing to the radioactivity were pointed out for each material. The experimental results for bismuth were compared with the calculations with DCAHIN-SP code. (author)

149

Thermally induced magnetic relaxation in building blocks of artificial kagome spin ice  

Science.gov (United States)

We have performed a study of thermally driven magnetic relaxation in building blocks of artificial kagome spin ice. For room-temperature measurements, we observe that low-energy states are accessed with high efficiency, particularly in structures with strong dipolar coupling and with low thicknesses. With carefully tuned heating experiments, we demonstrate how thermally active artificial spin ice systems relax magnetically from higher-energy states and eventually fall into low-energy states. The methods applied in our work offer the possibility to observe the thermodynamics of artificial spin ice systems in real space and time, and provide a way to directly investigate the nature of complex stochastic processes.

Farhan, Alan; Kleibert, Armin; Derlet, Peter M.; Anghinolfi, Luca; Balan, Ana; Chopdekar, Rajesh V.; Wyss, Marcus; Gliga, Sebastian; Nolting, Frithjof; Heyderman, Laura J.

2014-06-01

150

Radioactivity Assessment of Natural and Artificial Radionuclides in Soil Samples from Tha Phae, La-ngu and Thung Wa Districts in Satun Province, Thailand  

International Nuclear Information System (INIS)

Full text: Specific activities of natural (238U, 226Ra, 232Th and 40K) and artificial anthropogenic (137Cs) radionuclides in 65 soil samples collected from Tha Phae, La-ngu and Thung Wa Districts in Satun province have been measured and analyzed. Experimental results were obtained by using a high-purity germanium (HPGe) detector and gamma spectrometry analysis system. Experimental set-up and measurement were carried out at Nuclear and Material Physics Laboratory in Department of Physics Faculty of Science Thaksin University Songkhla Campus. The counting time for each sample was 10,800 seconds or 3 hours. It was found that the soil specific activities ranged from 0.00 to 11608.87 Bq/kg for 40K, 0.00 to 352.57 Bq/kg for 226Ra, 0.00 to 123.28 Bq/kg for 232Th and 0.00 to 16.28 Bq/kg for 137Cs with mean values of 3,248.96 ± 231.32 Bq/kg, 71.35 ± 5.97 Bq/kg, 53.59 ± 2.14 Bq/kg, and 0.68 ± 0.19 Bq/kg, respectively. Furthermore, the results were used to evaluate the absorbed dose rates in air (D), the radium equivalent (Raeq), the external hazard index (Hex) and the annual effective dose rate (AED) for this area. Moreover, the experimental results were compared to the previous data of the Office of Atoms for Peace (OAP). Thailand and global radioactivity measurements and evaluation, including the proposed recommended values the Organization for Economicd values the Organization for Economic Cooperation and Development (OECD, 1979) and the United Nations Scientific Committee on the Effects of Atomic Radiation

151

Dependence of Characteristics of SURA Induced Artificial ULF/VLF Signals on Geomagnetic Activity  

Science.gov (United States)

A comprehensive study of artificial ionospheric signal generation in the ULF/VLF bands at SURA facility in Russia was conducted during the past 4 years. We investigated the influence of geomagnetic activity on the characteristics of artificial low-frequency signals under the background of increasing solar activity. No correlation of artificial ULF signals with variations of Earth's magnetic field was observed for weak geomagnetic disturbances (Kp ? 3) while the VLF signals increased in the growth phase of the geomagnetic perturbation. In case of strong magnetic storm (Kp ? 5+) a tendency of the amplitude of the ULF/VLF signals decrease with increasing magnetic disturbance was observed. Sometimes, the modulation of artificial ULF signals with a period of 15-30 s was detected in the decay phase of magnetic storms. During storm time, a change in the polarization of artificial VLF emissions was detected. The right polarization becomes predominant. Interpretation of observed peculiarities of artificial VLF signals is given in the context of the physical mechanism of ionospheric current drive by RF pumping.

Kotik, D. S.; Ryabov, A. V.; Ermakova, E. N.; Pershin, A. V.

2015-04-01

152

Radioactive ion beams produced by neutron-induced fission at ISOLDE  

CERN Document Server

The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN, tests have been made on standard ISOLDE actinide targets using fast neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten an...

Catherall, R; Gilardoni, S S; Köster, U

2003-01-01

153

Does ozone enhance the remineralizing potential of nanohydroxyapatite on artificially demineralized enamel? A laser induced fluorescence study  

Science.gov (United States)

The present era of minimal invasive dentistry emphasizes the early detection and remineralization of initial enamel caries. Ozone has been shown to reverse the initial demineralization before the integrity of the enamel surface is lost. Nano-hydroxyapatite is a proven remineralizing agent for early enamel caries. In the present study, the effect of ozone in enhancing the remineralizing potential of nano-hydroxyapatite on artificially demineralized enamel was investigated using laser induced fluorescence. Thirty five sound human premolars were collected from healthy subjects undergoing orthodontic treatment. Fluorescence was recorded by exciting the mesial surfaces using 325 nm He-Cd laser with 2 mW power. Tooth specimens were subjected to demineralization to create initial enamel caries. Following which the specimens were divided into three groups, i.e ozone (ozonated water for 2 min), without ozone and artificial saliva. Remineralization regimen was followed for 3 weeks. The fluorescence spectra of the specimens were recorded from all the three experimental groups at baseline, after demineralization and remineralization. The average spectrum for each experimental group was used for statistical analysis. Fluorescence intensities of Ozone treated specimens following remineralization were higher than that of artificial saliva, and this difference was found to be statistically significant (Penamel. Ozone can be considered an effective agent in reversing the initial enamel caries there by preventing the tooth from entering into the repetitive restorative cycle.

Srinivasan, Samuelraj; Prabhu, Vijendra; Chandra, Subhash; Koshy, Shalini; Acharya, Shashidhar; Mahato, Krishna K.

2014-02-01

154

OXYTOCIN-INDUCED CERVICAL DILATION AND CERVICAL MANIPULATION IN SHEEP: EFFECTS ON LAPAROSCOPIC ARTIFICIAL INSEMINATION  

Science.gov (United States)

Difficulty of cervical penetration during transcervical artificial insemination (TAI), limits its use in sheep. Trauma of cervical manipulation (CM) may explain low fertility after TAI. We investigated effects of cervical dilation using exogenous oxytocin (OT) to facilitate TAI and its effect on rep...

155

Analysis of Correlation Between Urinal Excretion Ratio of Radioactive Iodine and Daily Urinal Excretion Volume  

International Nuclear Information System (INIS)

Internal exposure to radionuclide results from depositing of radioactive substance within human body and is called intra-body exposure as well. Radioactive substance may find its way into human body via nose, mouth or skin and internal exposure to radionuclide is rarely ascribable to radioactive substance deposited through skin. Radioactive substances deposited in human tissues or organs do not stay there for good. Instead, they are transferred to other tissues, organs or excreted by sweat, excrements, urine and breath. However, natural excretion has its limits in terms of safeguarding human body actively against radioactive exposure. When radionuclide is deposited in human organs or tissues, diuretic or evacuant is used to induce excrements or urine to increase removal and discharging of radionuclide artificially, thereby reducing internal exposure. Therefore, we have attempted to propose an optimum approach to removing and excreting radioactive iodine by analyzing the correlation among the radioactive iodine intake ratio, daily urinal excretion ratio and volume

156

Analysis of Correlation Between Urinal Excretion Ratio of Radioactive Iodine and Daily Urinal Excretion Volume  

Energy Technology Data Exchange (ETDEWEB)

Internal exposure to radionuclide results from depositing of radioactive substance within human body and is called intra-body exposure as well. Radioactive substance may find its way into human body via nose, mouth or skin and internal exposure to radionuclide is rarely ascribable to radioactive substance deposited through skin. Radioactive substances deposited in human tissues or organs do not stay there for good. Instead, they are transferred to other tissues, organs or excreted by sweat, excrements, urine and breath. However, natural excretion has its limits in terms of safeguarding human body actively against radioactive exposure. When radionuclide is deposited in human organs or tissues, diuretic or evacuant is used to induce excrements or urine to increase removal and discharging of radionuclide artificially, thereby reducing internal exposure. Therefore, we have attempted to propose an optimum approach to removing and excreting radioactive iodine by analyzing the correlation among the radioactive iodine intake ratio, daily urinal excretion ratio and volume.

Kim, Junghoon; Whang, Jooho [Kyunghee Univ., Yongin (Korea, Republic of); Kim, Teaman [The Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

2006-07-01

157

Features of artificial ULF/VLF signals induced by SURA facility under increased solar activity conditions  

Science.gov (United States)

It was conducted a comprehensive study of artificial ionospheric signal generation in the ULF/VLF bands at SURA facility during the past four years. We investigated the influence of geomagnetic activity on the characteristics of artificial low-frequency signals in recent years under the background of increasing solar activity. No correlation with variations of Earth's magnetic field was observed for weak geomagnetic disturbances (Kp increased for growth phase of the geomagnetic field perturbations during a small magnetic storms October 7, 2011 (Ki = 4 according to Moscow station). A similar pattern was traced in 2013 during storms March 21 (Kp = 5), May 24-25 (Kp = 5 +) and August 16 (Kp = 5 +). There are two possible reasons for the observed dependence - increasing the absorption of HF and VLF waves in the lower ionosphere, and / or reduction of the critical frequency of the F-layer, usually accompanied by a magnetic storm. The last factor is perhaps the most likely. This dependence was traced more convincingly on May 24-25, when during a storm time SURE had operated from evening until 6:00 MST in the morning. Signal amplitude explicitly followed the F- layer critical frequency variation. Some of the measurements in June 2012 were conducted during a magnetic storm on June 16-18, (Kp = 6). It was also found a decrease in the amplitude of the signal at the rise of the magnetic disturbance. In addition, during the daytime session 18.06.2012 during the recovery phase, it was detected modulation of artificial signals at frequencies 11 and 17 Hz with a period of 30 seconds. Note that the period of 30s is the main period of oscillation of the geomagnetic field line passing through the SURA facility, and more, the periods for torsional and the toroidal oscillation modes of this field line surprising coincidence for SURA geomagnetic latitude. Also the peculiarities were displayed in the polarization of artificial VLF signals during magnetic storms. Typically, the artificial emission is elliptically polarized at all frequencies of VLF signals with a predominance of the left- polarization. During a storm time, it was detected a change in the polarization of artificial VLF emissions. The right polarization becomes predominant. This fact can be associated with changes in ionospheric plasma parameters under a magnetic storm conditions. This work was supported by RFBR grants 13-02-0072 and 13-02-12074.

Kotik, Dmitry; Ryabov, Alexander; Pershin, Alexsander; Ermakova, Elena

158

Calculations of the production rate of radioactive nuclear beam induced by 70 MeV protons on 72Ge target  

International Nuclear Information System (INIS)

Under the condition of the calculated relative cross sections in good agreement with the experimental data, the production rate (s-1·?A-1) of the main radioactive nuclei induced by 70 MeV protons on 72Ge and its compound Zr5Ge3 targets are calculated by nuclear reaction model code SPEC. The calculated production rates of 72As and 71As are 2-3 times higher than the evaluated values abroad

159

Induced radioactivity analysis for the NSRL Linac in China using Monte Carlo simulations and gamma-spectroscopy  

OpenAIRE

The 200-MeV electron linac of the National Synchrotron Radiation Laboratory (NSRL) located in Hefei is one of the earliest high-energy electron linear accelerators in China. The electrons are accelerated to 200 MeV by five acceleration tubes and are collimated by scrapers. The scraper aperture is smaller than the acceleration tube one, so some electrons hit the materials when passing through them. These lost electrons cause induced radioactivity mainly due to bremsstrahlung ...

He, Lijuan; Li, Yuxiong; Li, Weimin; Chen, Zhi; Chen, Yukai; Ren, Guangyi

2014-01-01

160

Evaluation of a risk communication approach for maintenance staff working with induced radioactivity in medical linear accelerators  

International Nuclear Information System (INIS)

In order to promote consensus building on decommissioning operation rules for medical linear accelerators in Japan, we carried out a risk communication (RC) approach mainly providing knowledge for maintenance staff regarding induced radioactivity. In February 2012, we created a booklet (26 pages) to present an overview of the amended law, the mechanism and the distribution of induced radioactivity showing the actual radiation dose rate around a linear accelerator and actual exposure doses to staff. In addition, we co-sponsored a seminar for workers in this field organized by the Japan Medical Imaging and Radiological Systems Industries Association to explain the contents of this booklet, and answer questions regarding induced radioactivity of linear accelerators as an RC program. As a result, the understanding of staff regarding the regulations on maximum X-ray energy on linear accelerators (P<0.05), and the outline of clearance systems (P<0.01), were facilitated by RC. In addition, we found that about 70% of maintenance staff considered that the cooling time for decommissioning operation depended on the situation. Our RC approach suggests that consensus building should be used to make rules on decommissioning operations for linear medical accelerators. (author)

161

Induced radioactivity in rare-earth permanent magnets at 2.5 GeV electron accelerator  

Science.gov (United States)

Rare-earth permanent magnets such as Nd 2Fe 14B and Sm 2Co 17 are the main components of the insertion devices of synchrotron radiation facilities and are used at other particle accelerators. Due to radiation safety concern the induced radioactivity in permanent magnets at a 2.5 GeV electron accelerator were studied with Monte Carlo simulations and experiments. The saturated activity of each radioactive isotope was estimated with FLUKA code (2005 version) and compared with measurement results. Three models of NEOMAX Nd 2Fe 14B magnets and one trivial Sm 2Co 17 magnet were chosen as the test magnets. The remnant dose rate at 1 m from the magnet and its cooling time dependence are calculated with the induced activities from the view of radiation protection. These are investigated under unique radiation environments due to different target conditions. The transverse distributions of induced radioactivities of several representative isotopes, which were measured at different target conditions, agree well with the electromagnetic shower characteristics at different target conditions as well as the spatial distributions of photon and neutron fluences.

Qiu, Rui; Lee, Hee-Seock; Hong, Sukmo; Li, Junli; Bizen, T.

2007-06-01

162

Evaluation of potential induced radioactivity in medical products as a function of electron energy in electron beam sterilization  

Energy Technology Data Exchange (ETDEWEB)

Commercial sterilization of medical devices may be performed using electron beam irradiators at various electron energies. The potential for activating components of the devices has been discussed, with current standards stating that electron energy greater than 10 MeV requires assessment of potential induced radioactivity. This paper evaluates the potential for induced activity in medical products sterilized in electron beam as a function of the electron maximum energy. Monte Carlo simulation of a surrogate medical device was used to calculate photon and neutron fields resulting from electron irradiation, which were used to calculate concentrations for several radionuclides. The experiments confirmed that 10 MeV is a conservative assumption for limiting induced radioactivity. However, under the conditions as evaluated, which is a limited total quantity of metal in the material being irradiated and absent a limited number of elements; the amount of induced activity at 12 MeV could also be considered insignificant. The comparison of the sum-of-fractions to the US Nuclear Regulatory Commission exempt concentration limits is less than unity for all energies below 12.1 MeV, which suggests that there is minimal probability of significant induced activity at energies above the 10 MeV upper energy limit. - Highlights: > This study estimates induced radioactivity for electron irradiation as a function of energy. > MCNPX was used to model systems from 8 MeV up to 13 MeV. > Under conditions given, energies up to 12 MeV may create insignificant activation. > Measured concentrations were within a factor of two of those calculated. > Depth dose profiles show good agreement with the model.

Smith, Mark A., E-mail: msmith@sterigenics.com [Sterigenics International, 10811 Withers Cove Park Drive, Charlotte, NC 28211 (United States); Nuclear Engineering Teaching Laboratory, University of Texas at Austin, Austin, TX (United States)

2012-01-15

163

Artificial neural networks analysis of laser-induced fluorescence spectra for characterization of peripheral vascular tissue  

Science.gov (United States)

This study concerns the identification of the state of human peripheral vascular tissue by using Artificial Neural Networks. The fluorescence spectra, obtained by dual wavelength excitation of the tissue samples, were passed through a non-linear filter, based on a High Order Neural Network (HONN). Then a classical Multi-Layer Perceptron was employed to serve as the classifier of the feature vector. The above process resulted in the successful discrimination between normal and different types of pathological tissue.

Filippidis, George; Zacharakis, Giannis; Katsamouris, A.; Rovithakis, G. A.; Maniadakis, M.; Zervakis, M.; Papazoglou, Theodore G.

2001-01-01

164

Natural radioactivity contents in tobacco and radiation dose induced from smoking  

International Nuclear Information System (INIS)

One of the causative factors for cancer-inducing mechanisms in humans is radioactive elements present in tobacco leaves used in the manufacture of cigarettes. Smoking of tobacco and its products increases the internal intake and radiation dose due to naturally occurring radionuclides that are considered to be one of the most significant causes of lung cancer. In this work, different commercial types of cigarettes, cigar and moassel were collected from market. Naturally occurring radionuclides 226Ra and 214Bi (238U series), 228Ac and 228Ra (232Th series), 40K and man-made 137Cs were measured in tobacco using gamma-ray spectrometer. Results show that the average concentrations of 238U, 232Th and 40K were 4.564, 3.940 and 1289.53 Bq kg-1, respectively. This reflects their origin from the soil by root uptake and fertilisers used in the cultivation of tobacco plants. Concentration of 137Cs was 0.348 Bq kg-1 due to root uptake or deposition onto the leaf foliage. For smokers, the annual effective dose due to inhalation of 238U varied from 49.35 to 139.40 ?Sv-1 (average 104.27 ?Sv y-1), while of 232Th from 23.86 to 111.06 ?Sv y -1 (average 65.52 ?Sv y-1). The annual effective dose resulting from 137Cs was varied from 10.96 to 24.01 nSv y-1 (ave10.96 to 24.01 nSv y-1 (average 19.41 nSv y-1). (authors)

165

Radioactive ion beams produced by neutron-induced fission at ISOLDE  

International Nuclear Information System (INIS)

The production rates of neutron-rich fission products for the next-generation radioactive beam facility EURISOL [EU-RTD Project EURISOL (HPRI-CT-1999-50001)] are mainly limited by the maximum amount of power deposited by protons in the target. An alternative approach is to use neutron beams to induce fission in actinide targets. This has the advantage of reducing: the energy deposited by the proton beam in the target; contamination from neutron-deficient isobars that would be produced by spallation; and mechanical stress on the target. At ISOLDE CERN [E. Kugler, Hyperfine Interact. 129 (2000) 23], tests have been made on standard ISOLDE actinide targets using fast-neutron bunches produced by bombarding thick, high-Z metal converters with 1 and 1.4 GeV proton pulses. This paper reviews the first applications of converters used at ISOLDE. It highlights the different geometries and the techniques used to compare fission yields produced by the proton beam directly on the target with neutron-induced fission. Results from the six targets already tested, namely UC2/graphite and ThO2 targets with tungsten and tantalum converters, are presented. To gain further knowledge for the design of a dedicated target as required by the TARGISOL project [EU-RTD Project TARGISOL (HPRI-CT-2001-50033)], the results are compared to simulations, using the MARS [N.V. Mokhov, S.I. Striganov, A. Van Ginneken, S.G. Mashnik, A.J. Sierk, J. Ranft, MARS code developments, in: 4k, J. Ranft, MARS code developments, in: 4th Workshop on Simulating Accelerator Radiation Environments, SARE-4, Knoxville, USA, 14-15.9.1998, FERMILAB-PUB-98-379, nucl-th/9812038; N.V. Mokhov, The Mars Code System User's Guide, Fermilab-FN-628, 1995; N.V. Mokhov, MARS Code Developments, Benchmarking and Applications, Fermilab-Conf-00-066, 2000; O.E. Krivosheev, N.V. Mokhov, A New MARS and its Applications, Fermilab-Conf-98/43, 1998] code interfaced with MCNP [J.S. Hendrics, MCNP4C LANL Memo X-5; JSH-2000-3; J.F. Briemesteir (Ed.), MCNP - A General Montecarlo N-Particle Transport Code, Version 4C, LA-13709-M] libraries, of the neutron flux from the converters interacting with the actinide targets

166

Development of artificial red cells (ARC) produced by ?-ray induced polymerization of liposomes  

Science.gov (United States)

Artificial red cells (ARC) are prepared by encapsulating Hb with a polymerizable phospholipid. The polymerization of the vesicles were carried out with the irradiation of ?-rays. The irradiated ARC are physically more stable than any other known liposome type blood substitutes. Because of this stability, they can be easily stored under frozen condition for a long time. No significant changes were observed in vivo study with rats in which ARC were injected intravenously. The oxygen transport capacity of ARC was similar to that of native red blood cells.

Akama, K.; Awai, K.; Tokuyama, S.; Satoh, T.; Hosoi, F.; Omichi, H.

1995-08-01

167

Analysis of micro-composition of biological tissue by means of induced radioactivity  

Energy Technology Data Exchange (ETDEWEB)

The use of radioactive isotopes as tracers promises a wealth of information regarding the biochemical role of most elements and their components. Usually a radioactive sample of the element to be studied is administered to the plant or animal in a convenient form, and its distribution and rate of exchange are determined in later assays. This technique has, however, certain limitations, two of which will be discussed here: (1) radioactive isotopes are not generally useful for measurements of the concentration of elements in the body or its parts. They can be used only to give a measure of the rate of exchange of the elements and (2) the use of radioactive isotopes for tracer experiments requires that the radiation dose delivered to the tissue should be small in order not to disturb normal biological function.

Tobias, C.A.; Dunn, R.W.

1948-05-24

168

Two Electromagnetically Induced Transparency Windows and Cross-Phase Modulation with Four-Level Superconducting Artificial Atoms  

Science.gov (United States)

Superconducting circuit quantum electrodynamics (SCQED) employs microwave transmission lines coupled to artificial atoms, which are typical two-level and recently three-level for electromagnetically induced transparency (EIT). We propose SCQED with a four-level tripod-configuration artificial atom to enable cross-phase modulation between two traveling-wave microwave fields. Our master-equation analysis for three driving fields (``signal,'' ``probe'' and ``coupling'') demonstrates the existence of two distinct EIT transparency windows in the spectral-response profile as a function of coupling and weak fields strength. We provide the first theoretical analysis of this unexpected second window and show its advantages over the known first EIT window. Specifically we show that this second EIT window provides both the signal and probe fields with identical response functions provided that their Rabi frequencies and detunings are the same. Exploiting the second window with judiciously chosen external flux and energy detuning result in low absorption, excellent group velocity matching, and high nonlinearity, thereby enabling strong cross-phase modulation for SCQED.

Alotaibi, Hessa; Sanders, Barry

2013-03-01

169

Artificial granularity in two-dimensional arrays of nanodots fabricated by focused-electron-beam-induced deposition  

Science.gov (United States)

We have prepared 2D arrays of nanodots embedded in an insulating matrix by means of focused-electron-beam-induced deposition using the W(CO)6 precursor. By varying the deposition parameters, i.e. the electron beam current and energy and the raster constant, we obtain an artificial granular material with tunable electrical properties. The analysis of the temperature dependence of the conductivity and of the current-voltage characteristic suggests that the transport mechanism is governed by electron tunneling between artificial grains. In order to understand the nature of the granularity and thus the microstructural origin of the electronic transport behavior, we perform TEM and micro-Raman investigations. Independent of the deposition parameters, TEM measurements show that the dots are constituted of amorphous tungsten carbide clusters embedded in an amorphous carbonaceous matrix. Micro-Raman spectra show two peaks, around 690 and 860 cm - 1 associated with the W-C stretching modes. Higher frequency peaks give information on the composition of the matrix. In particular, we measure a peak at about 1290 cm - 1, which is associated with sp3 carbon bonds. Furthermore we detect the so-called D and G peaks, at about 1350 and 1560 cm - 1, associated with the vibration modes of the sp2 carbon bonds. The analysis of the position of the peaks and of their relative intensity suggests that the composition of the matrix is between nanocrystalline graphite and amorphous carbon.

Porrati, F.; Sachser, R.; Strauss, M.; Andrusenko, I.; Gorelik, T.; Kolb, U.; Bayarjargal, L.; Winkler, B.; Huth, M.

2010-09-01

170

Artificial granularity in two-dimensional arrays of nanodots fabricated by focused-electron-beam-induced deposition  

International Nuclear Information System (INIS)

We have prepared 2D arrays of nanodots embedded in an insulating matrix by means of focused-electron-beam-induced deposition using the W(CO)6 precursor. By varying the deposition parameters, i.e. the electron beam current and energy and the raster constant, we obtain an artificial granular material with tunable electrical properties. The analysis of the temperature dependence of the conductivity and of the current-voltage characteristic suggests that the transport mechanism is governed by electron tunneling between artificial grains. In order to understand the nature of the granularity and thus the microstructural origin of the electronic transport behavior, we perform TEM and micro-Raman investigations. Independent of the deposition parameters, TEM measurements show that the dots are constituted of amorphous tungsten carbide clusters embedded in an amorphous carbonaceous matrix. Micro-Raman spectra show two peaks, around 690 and 860 cm-1 associated with the W-C stretching modes. Higher frequency peaks give information on the composition of the matrix. In particular, we measure a peak at about 1290 cm-1, which is associated with sp3 carbon bonds. Furthermore we detect the so-called D and G peaks, at about 1350 and 1560 cm-1, associated with the vibration modes of the sp2 carbon bonds. The analysis of the position of the peaks and of their relative intensity suggests that the composition of the matrix isests that the composition of the matrix is between nanocrystalline graphite and amorphous carbon.

171

Artificial granularity in two-dimensional arrays of nanodots fabricated by focused-electron-beam-induced deposition  

Energy Technology Data Exchange (ETDEWEB)

We have prepared 2D arrays of nanodots embedded in an insulating matrix by means of focused-electron-beam-induced deposition using the W(CO){sub 6} precursor. By varying the deposition parameters, i.e. the electron beam current and energy and the raster constant, we obtain an artificial granular material with tunable electrical properties. The analysis of the temperature dependence of the conductivity and of the current-voltage characteristic suggests that the transport mechanism is governed by electron tunneling between artificial grains. In order to understand the nature of the granularity and thus the microstructural origin of the electronic transport behavior, we perform TEM and micro-Raman investigations. Independent of the deposition parameters, TEM measurements show that the dots are constituted of amorphous tungsten carbide clusters embedded in an amorphous carbonaceous matrix. Micro-Raman spectra show two peaks, around 690 and 860 cm{sup -1} associated with the W-C stretching modes. Higher frequency peaks give information on the composition of the matrix. In particular, we measure a peak at about 1290 cm{sup -1}, which is associated with sp{sup 3} carbon bonds. Furthermore we detect the so-called D and G peaks, at about 1350 and 1560 cm{sup -1}, associated with the vibration modes of the sp{sup 2} carbon bonds. The analysis of the position of the peaks and of their relative intensity suggests that the composition of the matrix is between nanocrystalline graphite and amorphous carbon.

Porrati, F; Sachser, R; Huth, M [Physikalisches Institut, Goethe-Universitaet, Max-von-Laue-Strasse 1, D-60438 Frankfurt am Main (Germany); Strauss, M [Max-Planck-Institut fuer Biophysik, Max-von-Laue-Strasse 3, D-60438 Frankfurt am Main (Germany); Andrusenko, I; Gorelik, T; Kolb, U [Institut fuer Physikalische Chemie, Johannes Gutenberg-Universitaet Mainz, Welderweg 11, D-55099 Mainz (Germany); Bayarjargal, L; Winkler, B [Institut fuer Geowissenschaften, Abt. Kristallographie, Goethe-Universitaet, Altenhoeferallee 1, D-60438 Frankfurt am Main (Germany)

2010-09-17

172

Prediction of Irradiation induced hardening by Artificial Neural Network for 304 and 316 stainless steels  

International Nuclear Information System (INIS)

The internal structures of pressurized water reactors (PWR) located close to the reactor core are used to support the fuel assemblies, to maintain the alignment between assemblies and the control bars and to canalize the primary water. In general these internal structures consist of baffle plates in a solution annealed (SA) 304 stainless steel and baffle bolts in a cold worked (CW) 316 stainless steel. These components undergo a large neutron flux at temperatures between 280 and 380 .deg. C. As a result, the materials exhibit a substantial increase in yield stress and a reduction in ductility which may deteriorate the performance of a reactor operation. For instance the observed cracks in bolts, usually attributed to irradiation assisted stress corrosion cracking (IASCC). In this work, we tried to apply a artificial neural network (ANN) approach to a prediction of a IASCC of an austenitic stainless steels SA 304 and CW 316. We have predicted the yield stress in terms of a dislocation loops size and density. Besides, we compared experimental data with prediction data by an artificial neural network

173

Morning sector drift-bounce resonance driven ULF waves observed in artificially-induced HF radar backscatter  

Science.gov (United States)

HF radar backscatter, which has been artificially-induced by a high power RF facility such as the EISCAT heater at Tromsø, has provided coherent radar ionospheric electric field data of unprecedented temporal resolution and accuracy. Here such data are used to investigate ULF wave processes observed by both the CUTLASS HF radars and the EISCAT UHF radar. Data from the SP-UK-OUCH experiment have revealed small-scale (high azimuthal wave number, m -45) waves, predominantly in the morning sector, thought to be brought about by the drift-bounce resonance processes. Conjugate observations from the Polar CAM-MICE instrument indicate the presence of a non-Maxwellian ion distribution function. Further statistical analysis has been undertaken, using the Polar TIMAS instrument, to reveal the prevalence and magnitude of the non-Maxwellian energetic particle populations thought to be responsible for generating these wave types.

Baddeley, L. J.; Yeoman, T. K.; Wright, D. M.; Davies, J. A.; Trattner, K. J.; Roeder, J. L.

2002-09-01

174

Results 2005 of the surveillance of the artificial radioactivity levels of aquatic ecosystems in the basin of Seine-Normandy. Riviere 2005  

International Nuclear Information System (INIS)

Set up in 2004 by the A.C.R.O. the citizens network of radioecological surveillance, information and evaluation (R.I.V.I.E.R.E.) aims at making a follow-up of the radioactive contamination of the aquatic ecosystems on the scale of the Seine-Normandy pond: from Nogent-on-Seine to La Hague and from the Mont-Saint-Michel to the Treport. The peculiarity of this network, which also makes its strength is to associate strictly all those who wish to appropriate the knowledge of the radioactivity levels around to them. With R.I.V.I.E.R.E., the citizen is at the same moment an author and an actor of the surveillance of his environment as his information. An approach defended by the A.C.R.O. since about 20 years and which has no equivalent anywhere else. This project has four main objectives: to know the levels and the tendencies of the present radioactivity in the main aquatic ecosystems of the Seine-Normandy widened pond, and so feed a data base including more than 3000 analysis (limited to the gamma radioactivity and to the tritium); to allow the citizens who put a lot to appropriate the knowledge and the indispensable references to understand the radioactivity of their environment; to establish a support in the public information about the radioactivity in environment; to supply data to the national network of measures of the radioactivity in environment, network established by decree recently and in charge of the evaluation of the public exposure. (N.C.)

175

The electrical charging of inactive aerosols in high ionised atmosphere, the electrical charging of artificial beta radioactive aerosols; Le processus de charge electrique: des aerosols non radioactifs en milieu fortement ionise, des aerosols radioactifs artificiels emetteurs beta  

Energy Technology Data Exchange (ETDEWEB)

The electrical properties of aerosols greatly influence their transport and deposition in a containment. In a bipolar ionic atmosphere, a neutral electric charge on aerosols is commonly assumed. However, many studies report a different charge distribution in some situations, like highly ionised atmosphere or in the case of radioactive aerosols. Such situations could arise from a hypothetical accident in a nuclear power plant. Within the framework of safety studies which are carried out at IPSN, our aims were the study of electrical properties of aerosols in highly ionised atmosphere, and the study of artificial radioactive aerosols, in order to suggest experimental validation of available theories. For this purpose, we designed an experimental device that allows us to measure non-radioactive aerosol charge distribution under high gamma irradiation, up to 10{sup 4} Gy/h. With our experimental device we also studied the properties of small ions in the medium. Our results show a variation of the charge distribution in highly ionised atmosphere. The charge increases with the dose of gamma ray. We have related this variation with the one of the small ions in the gases, according to theoretical prediction. However, the model overestimates slightly our experimental results. In the case of the radioactive aerosols, we have designed an original experimental device, which allows us to study the charge distribution of a {sup 137}Cs aerosol. Our results show that the electric charging of such aerosols is strongly dependent on evolution parameters in a containment. So, our results underline a great enhancement of self-charging of particles which are sampled in a confined medium. Our results are qualitatively in agreement with the theoretical model; nevertheless the latter underestimates appreciably the self-charging, owing to the fact that wall effects are not taken into account. (author)

Gensdarmes, F

2000-07-01

176

Measurement of the residual radioactivity induced in the front foil of a target assembly in a modern medical cyclotron  

International Nuclear Information System (INIS)

The levels of residual radioactivity induced in Havar[reg) foils at the entrance of a high-pressure 18O-enriched water target used for the production of 18F- in a medical cyclotron with 16 MeV protons have been determined using high-resolution ?-ray spectrometry. Whole body and skin dose rates arising from exposure to these foils during their periodic replacement have been estimated. The results indicate that irradiated foils do not represent a significant radiological hazard for the cyclotron operating staff and that no waste disposal difficulties should be encountered after an appropriate 'cooling' period of 2 years

177

5. Chemistry of radioactive elements  

International Nuclear Information System (INIS)

A review is given of the individual radioactive elements and artificial cisuranium and transuranium elements. The discovery, isotopes, chemical characteristics and compounds are shown for each. (M.D.)

178

Force induced and electron stimulated STM manipulations: routes to artificial nanostructures as well as to molecular contacts, engines and switches  

International Nuclear Information System (INIS)

Initially invented to image surfaces down to atomic scale, the scanning tunneling microscope (STM) has been further developed in the last few years to an operative tool, with which atoms and molecules can be manipulated at low substrate temperatures at will with atomic precision in different manners by using solely the tip-adparticle forces. In this way various artificial structures on nanoscale have been created and in situ characterized with the STM. Such structures as well as single molecules can be investigated by scanning tunnelling spectroscopy (STS) both with respect to their local electronic and even vibrational properties. Modifications of single molecules can be induced by using the tunnelling electron current: Rotations, diffusional jumps, vibrational excitations, desorption, dissociation and even association can be induced in individual molecules, often in a rather precise way by tuning the voltage into the energy levels of specific vibrations or electronic levels. These possibilities give rise to startling new opportunities for physical and chemical experiments on the single atom and single molecule level. Here a brief overview on results obtained with these new techniques is given

179

Induced radioactivity in the blood of cancer patients following Boron Neutron Capture Therapy  

International Nuclear Information System (INIS)

Since 1990, Boron Neutron Capture Therapy (BNCT) has been used for over 400 cancer patients at the Kyoto University Research Reactor Institute (KURRI). After BNCT, the patients are radioactive and their 24Na and 38Cl levels can be detected via a Na-I scintillation counter. This activity is predominantly due to 24Na, which has a half-life of 14.96 h and thus remains in the body for extended time periods. Radioactive 24Na is mainly generated from 23Na in the target tissue that is exposed to the neutron beam in BNCT. The purpose of this study is to evaluate the relationship between the radioactivity of blood 24Na following BNCT and the absorbed gamma ray dose in the irradiated field. To assess blood 24Na, 1 ml of peripheral blood was collected from 30 patients immediately after the exposure, and the radioactivity of blood 24Na was determined using a germanium counter. The activity of 24Na in the blood correlated with the absorbed gamma ray doses in the irradiated field. For the same absorbed gamma ray dose in the irradiated field, the activity of blood 24Na was higher in patients with neck or lung tumors than in patients with brain or skin tumors. The reasons for these findings are not readily apparent, but the difference in the blood volume and the ratio of bone to soft tissue in the irradiated field, as well as the dose that leaked through the clinical collimator, may be responsible. (author)

180

Artificially induced polyploidization in Humulus lupulus L. and its effect on morphological and chemical traits  

OpenAIRE

Chemically induced polyploids were obtained by the colchicine treatment of shoot tips of Humulus lupulus L. ‘Sybilla’. Flow cytometry revealed that most of the treatments resulted in the production of tetraploids. The highest number of tetraploids was obtained when explants were immersed in 0.05% colchicine for 48 h. A field experiment was conducted to compare diploid and tetraploid plants and assess the effect of genome polyploidization on the morphological and chemical characteristics. ...

Trojak-goluch, Anna; Skomra, Urszula

2013-01-01

181

Probing the connection of PBSs to the photosystems in Spirulina platensis by artificially induced fluorescence fluctuations  

International Nuclear Information System (INIS)

The molecular architecture and the structural connections of phycobilisomes (PBSs) to the photosystems in the intact cells of Spirulina platensis were studied by taking advantage of glycerol- and betaine-induced fluorescence fluctuations. Generally, with a selective excitation of C-phycocyanin (C-PC), glycerol could induce not only decoupling of PBSs from the photosystems but also of C-PC rods from allophycocyanin (APC) cores, while betaine could strengthen the connection of PBSs to the thylakoid membrane but induce a partial dissociation of PBS. On the other hand, glycerol did not exert an influence on the fluorescence spectra of the photosystems in isolated thylakoid membrane. Therefore, it was deduced that glycerol could provide a molecular environment to weaken the hydrophobic interactions of not only the LCM with the membrane but also the linker polypeptides to the water-soluble phycobiliproteins (C-PC and APC), while the betaine could strengthen the hydrophobic interaction of LCM with the membrane but weaken the electrostatic interaction of linker polypeptides to C-PC and/or APC

182

Probing the connection of PBSs to the photosystems in Spirulina platensis by artificially induced fluorescence fluctuations  

Energy Technology Data Exchange (ETDEWEB)

The molecular architecture and the structural connections of phycobilisomes (PBSs) to the photosystems in the intact cells of Spirulina platensis were studied by taking advantage of glycerol- and betaine-induced fluorescence fluctuations. Generally, with a selective excitation of C-phycocyanin (C-PC), glycerol could induce not only decoupling of PBSs from the photosystems but also of C-PC rods from allophycocyanin (APC) cores, while betaine could strengthen the connection of PBSs to the thylakoid membrane but induce a partial dissociation of PBS. On the other hand, glycerol did not exert an influence on the fluorescence spectra of the photosystems in isolated thylakoid membrane. Therefore, it was deduced that glycerol could provide a molecular environment to weaken the hydrophobic interactions of not only the L{sub CM} with the membrane but also the linker polypeptides to the water-soluble phycobiliproteins (C-PC and APC), while the betaine could strengthen the hydrophobic interaction of L{sub CM} with the membrane but weaken the electrostatic interaction of linker polypeptides to C-PC and/or APC.

Li Heng [Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Yang Shuzhen [Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Xie Jie [Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Zhao Jingquan [Key Laboratory of Photochemistry, Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China)]. E-mail: zhaojq@iccas.ac.cn

2007-01-15

183

Alloy development for fast induced radioactivity decay for fusion reactor applications  

International Nuclear Information System (INIS)

The Cr-Mo ferritic (martensitic) steels and austenitic stainless steels (primarily type 316 and variations on that composition) are the leading candidates for the structural components for future fusion reactors. However, irradiation of such steels in a fusion environment produces long-lived radioactive isotopes. These isotopes lead to difficult radioactive waste disposal problems once the structure is removed from service. Such problems could be reduced by developing steels that contain only elements that produce radioactive isotopes that decay to low levels in a reasonable time (tens of years instead of hundreds or thousands of years). This report discusses the development of such steels by making elemental substitutions in the steels now under consideration. Molybdenum must be replaced in the Cr-Mo steels; nickel and molybdenum both must be replaced in the austenitic stainless steels (the nitrogen concentration must be limited, and niobium, maintained to extremely low levels). Appropriate substitutions are tungsten for molybdenum in the Cr-Mo steels and manganese for nickel in the austenitic stainless steels. Indications are that suitable ferritic steels can be developed, but development of a nickel-free austenitic stainless steel with properties similar to the Cr-Ni stainless steels appears to be much more complex

184

Artificial radioactivity and marine environment: study of the transuranium elements 238Pu, 239+240Pu, 241Pu and 241Am in the Mediterranean  

International Nuclear Information System (INIS)

Both analytical and in situ measurements are discussed. The analytical part deals with the development of methods for the different radioelements studied, and stresses the quality obtained, particularly by participation in the intercalibration program organized by the International Laboratory of Marine Radioactivity (Monaco Oceanographic Museum) of the International Atomic Energy Agency. Chapter III concerns the different results of measurements on the distribution and behavior of the transuranium elements in the Mediterranean. Recommendations for future research directions are given

185

Early age sealing of buffer-rock gap by artificial wetting to induce bentonite swelling  

International Nuclear Information System (INIS)

Document available in extended abstract form only. The aim of this work is to study the homogeneous and rapid swelling of bentonite in the gap between the buffer blocks and the rock wall of the Olkiluoto disposal facility by artificial wetting. The focus was on the construction period of the deposition hole and buffer, and thus only the very early ages of the first weeks. In practice it is desirable that the bentonite material has a volume increase sufficient enough to prevent rock scaling while lowering the risks of bentonite piping and erosion due to potential water flow. This initial study was done in a small-scale mock-up in laboratory conditions. The small-scale steel mock-up had dimensions of 39 cm in height by 36 cm in diameter and included 12 pressure sensors, two displacement transducers, thermal couples, and pore water pressure measurements. The radial and axial pressure development was typically measured over a two week period to assess the rate and magnitude of sealing. A steel confining lid was used for simulating overpressure, though in some cases a plexiglass lid was used to take video images of the gap sealing. The buffer blocks were produced by isostatic compression of 100 MPa. The material was MX-80 Wyoming bentonite having a water content of approximately 13% and a dry density of 1890 kg/m3. The testing samples were dry sawn and core drilled from the large block and machined to their final dimensions. These were typically 30 x 30 cm, eithons. These were typically 30 x 30 cm, either as a solid block or three disks of 10 cm height each. The diameter was sometimes varied to allow for a change of gap width between 25 to 50 mm The study included various scenarios, such as: eccentric aligned blocks with gap sizes of 5 and 45 mm, free upward swelling or confinement, different types of pellet and granular gap filling, addition of water at varying rates, and longer term test duration. The samples were typically disassembled after two weeks. At this ending point, material assessments were done to quantify the variation of water content, SHORE hardness and density across the buffer and gap filling. The results showed that the bentonite buffer exposed to rapid artificial wetting is able to uniformly swelling to fill the gap within the first day with 25 mm gap. When only a water-filled gap was used, a radial pressure of about 200 kPa was achieved within the first few days with gas-tight steel lid in use. The pressure reached a maximum after about 2 weeks and then gradually declined due to moisture distribution from the gap towards the centre of the buffer block. Radial cracks appeared within the blocks within the test duration, which extended the full depth and across blocks. These could tighten and seal with prolonged testing or water addition. When gap filling materials were used, such as Cebogel pellets or Ibeco Seal granules, the radial pressure had maximum values up to 600 kPa. The pressure developed at a much faster rate and was better maintained over time, without the same type of pressure drop experienced with only an air-water filled gap. It was demonstrated that water could percolate through the pellet filling to be evenly distributed within a few minutes. This was also achieved in longer tube-filling tests simulating actual deposition holes, showing that when the pellets were placed by free-falling there was enough void space to allow full water filtration. The swollen material was well confined in the gap when an axial confining pressure was used from the start of testing. In some cases, the vertical, or axial, uplift pressure due to swelling was as much as double the radial pressure. Yet this could theoretically be counter-balanced by applying a confining load or lid to prevent buffer uplift into the tunnel backfill area. These post-test assessments showed that moisture equilibrium between the gap and buffer was not reached within the short test duration as expected. The outer gap filled material could have water contents on the order of 100 to 400% of the buffer. The area near the top of the sample of

186

Ambient radioactivity levels and radiation doses. Annual report 2012  

International Nuclear Information System (INIS)

The annual report 2012 on ambient radioactivity levels and radiation doses covers the following issues: Part A: General information: natural environmental radioactivity; artificial radioactivity in the environment; occupational radiation exposure; radiation exposures from medical applications; the handling of radioactive materials and sources of ionizing radiation; non-ionizing radiation. Part B: Current data and their evaluation: natural environmental radioactivity; artificial radioactivity in the environment; occupational radiation exposures; radiation exposures from medical applications; the handling of radioactive materials and sources of ionizing radiation; non-ionizing radiation. The report includes data on the stock of radioactive waste, radiation accidents and unusual events.

187

Production and properties of radioactivity  

International Nuclear Information System (INIS)

In a book on 'Medical Physics', one of the chapters discusses the production and physical properties of radioactivity. This includes radioactive decay, activity and half-life, the emission and properties of nuclear radiations and the production of artificial isotopes. At the end of the chapter, there are questions on the content of the chapter. (UK)

188

Diagnostic accuracy of artificially induced vertical root fractures: a comparison of direct digital periapical images with conventional periapical images  

Energy Technology Data Exchange (ETDEWEB)

To compare the diagnostic accuracy for the detection of root fractures in CMOS-based digital periapical images with conventional film-based periapical images. Sixty extracted single-root human teeth with closed apices were prepared endodontically and divided into two groups; artificially induced vertical root fracture group and control group. All radiographs were obtained using the paralleling technique. The radiographs were examined by 4 observers three times within a 4 week interval. Receiver operating characteristic (ROC) analysis was carried out using data obtained from four observers. Intra- and inter-examiner agreements were computed using kappa analysis. The area under the ROC curve (Az) was used as an indicator of the diagnostic accuracy of the imaging system. Az values were as follows: direct-digital images; 0.93, film-based images; 0.92, and inverted digital images; 0.91. There was no significant difference between imaging modalities(P<0.05). The kappa value of inter-observer agreement was 0.42(range:0.28-0.60) and intra-observer agreement was 0.57(range:0.44-0.75). There is no statistical difference in diagnostic accuracy for the detection of vertical root fractures between digital periapical images and conventional periapical images. The results indicate that the CMOS sensor is a good image detector for the evaluation of vertical root fractures.

Lee, Ji Un; Kwon, Ki Jeong; Koh, Kwang Joon [Chonbuk National University College of Medicine, Chonju (Korea, Republic of)

2004-12-15

189

Diagnostic accuracy of artificially induced vertical root fractures: a comparison of direct digital periapical images with conventional periapical images  

International Nuclear Information System (INIS)

To compare the diagnostic accuracy for the detection of root fractures in CMOS-based digital periapical images with conventional film-based periapical images. Sixty extracted single-root human teeth with closed apices were prepared endodontically and divided into two groups; artificially induced vertical root fracture group and control group. All radiographs were obtained using the paralleling technique. The radiographs were examined by 4 observers three times within a 4 week interval. Receiver operating characteristic (ROC) analysis was carried out using data obtained from four observers. Intra- and inter-examiner agreements were computed using kappa analysis. The area under the ROC curve (Az) was used as an indicator of the diagnostic accuracy of the imaging system. Az values were as follows: direct-digital images; 0.93, film-based images; 0.92, and inverted digital images; 0.91. There was no significant difference between imaging modalities(P<0.05). The kappa value of inter-observer agreement was 0.42(range:0.28-0.60) and intra-observer agreement was 0.57(range:0.44-0.75). There is no statistical difference in diagnostic accuracy for the detection of vertical root fractures between digital periapical images and conventional periapical images. The results indicate that the CMOS sensor is a good image detector for the evaluation of vertical root fractures.

190

Morning sector drift-bounce resonance driven ULF waves observed in artificially-induced HF radar backscatter  

Directory of Open Access Journals (Sweden)

Full Text Available HF radar backscatter, which has been artificially-induced by a high power RF facility such as the EISCAT heater at Tromsø, has provided coherent radar ionospheric electric field data of unprecedented temporal resolution and accuracy. Here such data are used to investigate ULF wave processes observed by both the CUTLASS HF radars and the EISCAT UHF radar. Data from the SP-UK-OUCH experiment have revealed small-scale (high azimuthal wave number, m -45 waves, predominantly in the morning sector, thought to be brought about by the drift-bounce resonance processes. Conjugate observations from the Polar CAM-MICE instrument indicate the presence of a non-Maxwellian ion distribution function. Further statistical analysis has been undertaken, using the Polar TIMAS instrument, to reveal the prevalence and magnitude of the non-Maxwellian energetic particle populations thought to be responsible for generating these wave types.

Key words. Ionosphere (active experiments; wave-particle interactions Magnetospheric physics (MHD waves and instabilities

L. J. Baddeley

191

Piezomagnetic effects induced by artificial sources at Mt. Vesuvius (Italy: preliminary results of an experimental survey  

Directory of Open Access Journals (Sweden)

Full Text Available In order to put new constrains on magnetic effects associated with mechanical stresses, high frequency monitoring of the geomagnetic field was carried out during a seismic tomography experiment (TOMOVES'96 project at Mt. Vesuvius. Eight proton precession and one Cesium magnetometers were installed along a profile on the SW flank of the volcano to observe possible magnetic changes induced by explosions. Measurements were performed at different sampling frequencies (10 Hz, 0.5 Hz and 0.1 Hz. A remarkable change in the intensity of the magnetic field was observed in only one case. The magnetic transient lasted 12-13 min, reaching the maximum amplitude of slightly less than 15 nT.

R. Napoli

1998-06-01

192

Double pulse laser induced breakdown spectroscopy applied to natural and artificial materials from cultural heritages  

International Nuclear Information System (INIS)

The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown in recent years its great potential for rapid qualitative analysis of materials. Thanks to the possibility to implement a portable instrument that perform LIBS analysis, this technique is revealed to be particularly useful for in situ analysis in the field of cultural heritages. The purpose of this work is to evaluate the potentiality of LIBS technique in the field of cultural heritages, with respect to the chemical characterization of complex matrix as calcareous and refractory materials for further quantitative analyses on cultural heritages. X-Ray Fluorescence (XRF) analyses were used as reference. Calibration curves of certified materials used as standards were obtained by XRF analyses. The LIBS measurements were performed with a new mobile instrument called Modi (Mobile Double pulse Instrument for LIBS Analysis). The XRF analyses were performed with a portable instrument ArtTAX. LIBS and XRF measurement were performed on both reference materials and samples (bricks and mortars) sampled in the ancient Greek-Roman Theatre of Taormina. Although LIBS measurements performed on reference materials have shown non linear response to concentrations, and so we were not able to obtain quantitative results, an integrated study of XRF and LIBS signals permitted us to distinguish among chemical features and degradation state of measured building materials.ding materials.

193

Artificially induced polyploidization in Humulus lupulus L. and its effect on morphological and chemical traits.  

Science.gov (United States)

Chemically induced polyploids were obtained by the colchicine treatment of shoot tips of Humulus lupulus L. 'Sybilla'. Flow cytometry revealed that most of the treatments resulted in the production of tetraploids. The highest number of tetraploids was obtained when explants were immersed in 0.05% colchicine for 48 h. A field experiment was conducted to compare diploid and tetraploid plants and assess the effect of genome polyploidization on the morphological and chemical characteristics. Tetraploids showed significant differences in relation to diploids. They had thinner and shorter shoots. The influence of chromosome doubling was also reflected in the length, width and area of leaves. The length of female flowers in the tetraploids was significantly shorter than that observed in diploids. Tetraploids produced a diverse number of lupuline glands that were almost twice as large as those observed in diploids. The most distinct effect of genome polyploidization was a significant increase in the weight of cones and spindles. Contents of major chemical constituents of hop cones was little affected by ploidy level. Total essential oils were significantly lower than those in diploids. However there was a significant increase in the proportion of humulene, caryophyllene and farnesene, oils desired by the brewing industry. PMID:24399911

Trojak-Goluch, Anna; Skomra, Urszula

2013-12-01

194

Urease-induced calcification of segmented polymer hydrogels - a step towards artificial biomineralization.  

Science.gov (United States)

Natural organic/inorganic composites, such as nacre, bones and teeth, are perfectly designed materials with exceptional mechanical properties. Numerous approaches have been taken to synthetically prepare such composites. The presented work describes a new way of mineralizing bulk materials on a large scale following the approach of bioinduced mineralization. To this end, a series of polymer conetworks with entrapped urease were prepared. After polymerization, the entrapped urease shows high enzymatic activity. The bioactive polymer conetworks were then treated with an aqueous mixture of urea and CaCl2. The urease-induced calcification indeed allows formation of carbonate crystals exclusively within the hydrogel even at room temperature. The influence of network composition, degree of cross-linking, immobilized urease concentration and temperature of calcification were investigated. By varying these parameters, spherical, monolithic clusters, as well as bar-like nanocrystals with different aspect ratios in spherical or dendritic arrays, are formed. The grown nanocrystals improve the stiffness of the starting material by up to 700-fold, provided that the microstructure shows a dense construction without pores and strong interaction between crystals and network. The process has the potential to generate a new class of hybrid materials that would be available on the macroscopic scale for use in lightweight design and medicine. PMID:24887285

Rauner, Nicolas; Meuris, Monika; Dech, Stephan; Godde, Julia; Tiller, Joerg C

2014-09-01

195

Cardiomyopathy induced by artificial cardiac pacing: myth or reality sustained by evidence? / Miocardiopatia dilatada induzida por estimulação cardíaca artificial: mito ou realidade sustentada pelas evidências?  

Scientific Electronic Library Online (English)

Full Text Available A estimulação cardíaca artificial (ECA) é o tratamento mais seguro e eficaz para a bradicardia sintomática irreversível. Nas indicações propícias, pode trazer grande benefício clínico. Contudo, as evidências mostram que a ação da ECA geraria, em alguns casos, efeitos deletérios à estrutura e fisiolo [...] gia cardíacas. Este potencial efeito negativo da ECA convencional poderia ser mais acentuado principalmente em pacientes com comprometimento prévio da função ventricular esquerda e, sobretudo, quando o eletrodo é colocado em posição apical do ventrículo direito (VD). Intrigante é, contudo, que após quase 6 décadas de ECA do VD, apenas uma reduzida parcela de pacientes apresenta esta condição clinicamente manifesta. Os determinantes do surgimento ou não da cardiopatia por ECA não estão totalmente esclarecidos. Ainda é motivo de debate a existência de uma relação de causalidade entre o padrão de BRE artificial secundário à ativação antifisiológica ventricular, alterações da dinâmica contrátil ventricular, e condições clínicas (disfunção sistólica prévia, cardiopatia estrutural preexistente, tempo desde o implante) ou elétricas (duração do intervalo QRS, dose percentual de estimulação ventricular). Esta revisão aborda dados contemporâneos sobre esta nova entidade e discute alternativas de como utilizar a ECA neste contexto, com ênfase na terapia de ressincronização cardíaca. Abstract in english Implantable cardiac pacing systems are a safe and effective treatment for symptomatic irreversible bradycardia. Under the proper indications, cardiac pacing might bring significant clinical benefit. Evidences from literature state that the action of the artificial pacing system, mainly when the vent [...] ricular lead is located at the apex of the right ventricle, produces negative effects to cardiac structure (remodeling, dilatation) and function (dissinchrony). Patients with previously compromised left ventricular function would benefit the least with conventional right ventricle apical pacing, and are exposed to the risk of developing higher incidence of morbidity and mortality for heart failure. However, after almost 6 decades of cardiac pacing, just a reduced portion of patients in general would develop these alterations. In this context, there are not completely clear some issues related to cardiac pacing and the development of this cardiomyopathy. Causality relationships among QRS widening with a left bundle branch block morphology, contractility alterations within the left ventricle, and certain substrates or clinical (previous systolic dysfunction, structural heart disease, time from implant) or electrical conditions (QRS duration, percentage of ventricular stimulation) are still subjecte of debate. This review analyses contemporary data regarding this new entity, and discusses alternatives of how to use cardiac pacing in this context, emphasizing cardiac resynchronization therapy.

Andrés Di Leoni, Ferrari; Anibal Pires, Borges; Luciano Cabral, Albuquerque; Carolina Pelzer, Sussenbach; Priscila Raupp da, Rosa; Ricardo Medeiros, Piantá; Mario, Wiehe; Marco Antônio, Goldani.

2014-09-01

196

Prompt radiation, shielding and induced radioactivity in a high-power 160 MeV proton linac  

Energy Technology Data Exchange (ETDEWEB)

CERN is designing a 160 MeV proton linear accelerator, both for a future intensity upgrade of the LHC and as a possible first stage of a 2.2 GeV superconducting proton linac. A first estimate of the required shielding was obtained by means of a simple analytical model. The source terms and the attenuation lengths used in the present study were calculated with the Monte Carlo cascade code FLUKA. Detailed FLUKA simulations were performed to investigate the contribution of neutron skyshine and backscattering to the expected dose rate in the areas around the linac tunnel. An estimate of the induced radioactivity in the magnets, vacuum chamber, the cooling system and the concrete shield was performed. A preliminary thermal study of the beam dump is also discussed.

Magistris, Matteo [CERN, CH-1211 Geneva 23 (Switzerland)]. E-mail: matteo.magistris@cern.ch; Silari, Marco [CERN, CH-1211 Geneva 23 (Switzerland)

2006-06-23

197

Correlation between radioactivity induced inside the treatment room and the undesirable thermal/resonance neutron radiation produced by linac.  

Science.gov (United States)

High-energy therapeutic beams used in the radiotherapy induce photonuclear and electronuclear reactions which are accompanied by generation of undesirable radioisotopes and neutrons inside the treatment room. These neutrons at thermal and resonance energies induce nuclear reactions through the whole accelerator bunker. In consequence various radioisotopes emitting high-energy photons appear. In this paper the correlation between radioactivity induced inside the treatment room and the undesirable thermal and resonance neutron radiation generated by the therapeutic accelerator X-rays was studied. The thermal and resonance neutron fluence determined in chosen places inside the bunkers was 1.0x10(5)-3.4x10(5)cm(-2)Gy(-1) and 1.0x10(5)-1.6x10(6)cm(-2)Gy(-1) at thermal energies (epithermal energies (0.1eV-10keV), for the 15MV and 20MV beams, respectively. The gamma energy spectra measured inside the accelerator bunker depended on the neutron radiation level. The net count rates of the gamma peaks from the decays of the excited state (56)Fe* and (28)Si*, the result of the simple capture of the neutron, for the 20MV beam were almost one order of magnitude greater than those for the 15MV beam. Moreover, it turned out that the activation of the wedge - the main accelerator accessory was caused by neutrons. PMID:18339569

Konefa?, Adam; Orlef, Andrzej; Dybek, Marcin; Maniakowski, Zbigniew; Polaczek-Grelik, Kinga; Zipper, Wiktor

2008-12-01

198

A novel method to detect pressure-induced sensor attenuations (PISA) in an artificial pancreas.  

Science.gov (United States)

Continuous glucose monitors (CGMs) provide real-time interstitial glucose concentrations that are essential for automated treatment of individuals with type 1 diabetes. Miscalibration, noise spikes, dropouts, or pressure applied to the site (e.g., lying on the site while sleeping) can cause inaccurate glucose signals, which could lead to inappropriate insulin dosing decisions. These studies focus on the problem of pressure-induced sensor attenuations (PISAs) that occur overnight and can cause undesirable pump shut-offs in a predictive low glucose suspend system. The algorithm presented here uses real-time CGM readings without knowledge of meals, insulin doses, activity, sensor recalibrations, or fingerstick measurements. The real-time PISA detection technique was tested on outpatient "in-home" data from a predictive low-glucose suspend trial with over 1125 nights of data. A total of 178 sets were created by using different parameters for the PISA detection algorithm to illustrate its range of available performance. The tracings were reviewed via a web-based analysis tool by an engineer with an extensive expertise on analyzing clinical datasets and ~3% of the CGM readings were marked as PISA events which were used as the gold standard. It is shown that 88.34% of the PISAs were successfully detected by the algorithm, and the percentage of false detections could be reduced to 1.70% by altering the algorithm parameters. Use of the proposed PISA detection method can result in a significant decrease in undesirable pump suspensions overnight, and may lead to lower overnight mean glucose levels while still achieving a low risk of hypoglycemia. PMID:25316716

Baysal, Nihat; Cameron, Fraser; Buckingham, Bruce A; Wilson, Darrell M; Chase, H Peter; Maahs, David M; Bequette, B Wayne

2014-11-01

199

Assessment of natural and artificial radioactivity levels and radiation hazards and their relation to heavy metals in the industrial area of Port Said city, Egypt.  

Science.gov (United States)

A detailed gamma ray spectrometry survey was carried out to make an action in environmental impact assessment of urbanization and industrialization on Port Said city, Egypt. The concentrations of the measured radioelements U-238, Th-232 in ppm, and K-40 %, in addition to the total counts of three selected randomly dumping sites (A, B, and C) were mapped. The concentration maps represent a base line for the radioactivity in the study area in order to detect any future radioactive contamination. These concentrations are ranging between 0.2 and 21 ppm for U-238 and 0.01 to 13.4 ppm for Th-232 as well as 0.15 to 3.8 % for K-40, whereas the total count values range from 8.7 to 123.6 uR. Moreover, the dose rate was mapped using the same spectrometer and survey parameters in order to assess the radiological effect of these radioelements. The dose rate values range from 0.12 to 1.61 mSv/year. Eighteen soil samples were collected from the sites with high radioelement concentrations and dose rates to determine the activity concentrations of Ra-226, Th-232, and K-40 using HPGe spectrometer. The activity concentrations of Ra-226, Th-232, and K-40 in the measured samples range from 18.03 to 398.66 Bq kg(-1), 5.28 to 75.7 Bq kg(-1), and 3,237.88 to 583.12 Bq kg(-1), respectively. In addition to analyze heavy metal for two high reading samples (a 1 and a 10) which give concentrations of Cd and Zn elements (a 1 40 ppm and a 10 42 ppm) and (a 1 0.90 ppm and a 10 0.97 ppm), respectively, that are in the range of phosphate fertilizer products that suggested a dumped man-made waste in site A. All indicate that the measured values for the soil samples in the two sites of three falls within the world ranges of soil in areas with normal levels of radioactivity, while site A shows a potential radiological risk for human beings, and it is important to carry out dose assessment program with a specifically detailed monitoring program periodically. PMID:25233912

Attia, T E; Shendi, E H; Shehata, M A

2015-02-01

200

Induced structural radioactivity inventory analysis of the base case aqueous ATW reactor concept  

International Nuclear Information System (INIS)

The purpose of the Los Alamos National Laboratory Accelerator Transmutation of Nuclear Waste (ATW) project is the substantial reduction in volume of this country's long-lived high-level radioactive waste in a safe and energy efficient manner. An evaluation of the Accelerator Transmutation of Nuclear Waste concept has four aspects; material balance, energy balance, performance and cost. An evaluation of the material balance compares the amount of long-lived high-level waste transmuted with the amount and type of waste created in the process. One component of the material balance is the activation of structural materials over the lifetime of the transmutation reactor. An activation analysis has been performed on four structure regions of the reaction vessel: the tungsten target; the lead target and annulus; the Zircalloy and aluminum tubing carrying the actinide slurry and; the stainless steel tank

201

Natural ?-radioactivity of sea water of the Usury Bay induced by 226 Ra  

International Nuclear Information System (INIS)

Dynamics of seawater contamination in Ussury Bay of the Sea of Japan was studied by tracer technique and numerical three-dimensional simulation of turbulent transfer of impurities. Radioactive background of the water brought about by 226 Ra was studied, as well. Promising character of 226 Ra use as a tracer is shown. Methods and facility for 226 Ra measurement in 1 l samples have been worked out. The content of 226 Ra was measured by the method of extraction of gaseous 222 Rn formed in the course of decay and its activity determination. The method sensitivity, when the effect equals the background, is 0.5 x 10-15 Ci/l. The data obtained on 226 Ra content in seawater of the Ussury Bay with description of the place of sampling are provided. 5 refs., 1 fig., 1 tab

202

Tide induced mathematical model for coastal radioactive discharges and its application  

International Nuclear Information System (INIS)

A mathematical model has been developed to evaluate spatial and temporal distribution of radionuclide concentration from a continous discharge of radioactive liquid effluents into the Tarapur coastal waters, taking into consideration tidal effects and seasonal variation of ocean currents. It is found that all the nuclides studied except 131I, attain steady state concentration more or less at the same time interval after continuous discharge, depending on the distance along the coast. Further, the confinement of radionuclides parallel to the coast is significant. Limiting discharge rates (LDR) for some typical radionuclides have also been computed using a radiological model. The calculations show the the LDR values vary from 7 to 50,000 Ci.d-1, the lowest and highest being for 239Pu and 134Cs respectively. (author)

203

A quantitative analysis of microbially-induced calcite precipitation employing artificial and naturally-occurring sediments  

Science.gov (United States)

Microbially-induced calcite precipitation is a strong candidate for the production of sustainable construction materials. The process employs the microbe Sporosarcina pasteurii as an agent to microbially mediate the precipitation of calcium carbonate to bind unconsolidated sediment. As this process can be achieved under ambient temperature conditions and can utilise a wide variety of easily-available sediments, potentially including waste materials, it is envisioned that this procedure could significantly reduce carbon-dioxide emissions in the construction industry. This study describes and quantifies the precipitation of calcite cement in a range of naturally-occurring sediments compared with a control matrix. The study establishes the optimum treatment time for effective cement precipitation in order to produce a material that meets the standards required for construction whilst keeping economic and environmental outlays at a minimum. The 'control sediment' employed industrial-grade glass beads with a grain size range of 595-1180 microns (16-30 US mesh). Sporosarcina pasteurii were mixed in a solution of urea and calcium chloride and then inoculated into the control sediment. The microbes attach to the surface of the sediment grains and employ urea as a source of energy to produce ammonia and carbon dioxide. By so doing, they increase the pH of the solution allowing calcium carbonate to precipitate at the cell walls to act as nucleation points facilitating the precipitation of cements as a grain-coating and biocementing the unconsolidated sediment. The solution treatment was repeated at eight hour intervals with samples removed for detailed analysis after each every five consecutive treatments (i.e. 40 hours). The process was repeated to produce 20 samples with treatment times between 40 and 800 hours. Cemented samples were impregnated with blue epoxy and examined petrographically to monitor cement development. Modal analysis was undertaken on each cemented sample to establish the abundance and natures of precipitated cements. Samples were also examined via SEM to monitor cement distribution and quantify the thickness of cements on grain surfaces and at grain-on-grain contacts. Analysis established that precipitation of calcite continues until 400 hours (50 treatments) after which time there is only an insignificant precipitation of new calcite cement. This is inferred to result from the occlusion of porosity (from 40% to 10%) and observed calcite precipitation at grain-on-grain contacts, both factors reduce the permeability of the samples and, thus, inhibit the flow of solution through the medium. The precipitated calcite cement was found to be dominantly grain-rimming with a consistent thickness averaging 11 microns. A range of naturally-occurring sediments were collected from surface locations throughout the United Arab Emirates. Samples were submitted to a range of petrographic and geochemical analysis in order to quantify grain-size distribution, grain composition and bulk total carbonate content (7.5-94 wt%). Sub-samples of these sediments were established by sieving and the cementation potential of different size fractions was established. Following treatment, these samples were submitted to the same analysis as those employed for the control sediment. A relationship between both sediment grain-size characteristics and sediment grain composition to cement precipitation was established and is discussed.

Lokier, Stephen; Krieg Dosier, Ginger

2013-04-01

204

Indução à ovulação pelo uso de LHRH análogo e fertilização artificial em rã-touro (Rana catesbeiana) / Spawning inducing by analog LHRH and artificial fertilization of bullfrog (Rana catesbeiana)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Este trabalho teve por objetivo aperfeiçoar a técnica de reprodução induzida existente para rã-touro, com o intuito de aumentar a taxa de fecundidade e viabilizar seu uso pelo produtor. As doses hormonais para a indução da ovulação e espermiação seguiram as propostas de FALCON e CULLEY (1995) e ALON [...] SO (1997); entretanto, a técnica de fertilização artificial foi adaptada da metodologia para reprodução artificial de peixes com ovos não-aderentes (WOYNAROVICH e HORVÁTH, 1983). A técnica proposta apresenta as seguintes etapas: I) sincronização da ovulação e da espermiação, por meio de hormônio liberador de gonadotropina ((Des-Gli10, D-His(Bzl)6, Pro-NHEt9)-LHRH)); II) extração dos óvulos de cada fêmea (1 a 2 minutos); III) fertilização dos óvulos (2 minutos) com líquido espermático diluído em 100 mL de água; IV) hidratação dos ovos em 10 a 20 litros de água; e V) incubação dos ovos em quadros de tela de 1x 0,70 m, com malha de 1 mm. As taxas de fertilização obtidas com as modificações propostas foram superiores a 60%. Ressalta-se ainda que a técnica propiciou a obtenção, a partir de um mesmo animal, de várias desovas, sendo que cada fêmea pode ovular em intervalos de, aproximadamente, 45 dias. Abstract in english The objective of this study was to improve the artificial fertilization techniques for bullfrog, to increase the fertilization rate and become their use accessible for frog producers. Hormone dosages for inducing ovulation and spermiation followed those proposed by FALCON and CULLEY (1995) and ALONS [...] O (1997); however, the artificial fertilization technique was adapted from the available methodology for artificial reproduction of fish with non-adhering eggs (WOYNAROVICH e HORVÁTH, 1983). The proposed technique consists of the following steps: I) synchronization of ovulation and spermiation through gonadotropin releasing hormone ((Des-Gli10, D-His(Bzl)6, Pro-NHEt9)-LHRH)); II) complete ovule extrusion in every female (1 to 2 minutes); III) ovule fertilization (2 minutes) with sperm diluted in 100 mL water; IV) ova hydration in 10 - 20 L water; V) ova incubation in screen frames, measuring 1,0 x 0,7 m, with 1 mm screen size. Fertilization rate obtained with the proposed modifications stayed above 60 %. It should also be emphasized that the proposed techniques allowed to obtain several spawns from the same frog, and each female was able to ovulate, approximately, every 45 days.

Claudio Angelo, Agostinho; Francisco Stefano, Wechsler; Paulo Eduardo de Oliveira, Nictheroy; Daniela Felipe, Pinheiro.

1261-12-01

205

Artificial Intelligence.  

Science.gov (United States)

This issue of "Information Technology Quarterly" is devoted to the theme of "Artificial Intelligence." It contains two major articles: (1) Artificial Intelligence and Law" (D. Peter O'Neill and George D. Wood); (2) "Artificial Intelligence: A Long and Winding Road" (John J. Simon, Jr.). In addition, it contains two sidebars: (1) "Calculating and…

Information Technology Quarterly, 1985

1985-01-01

206

Analysis of natural and artificial ultramarine blue pigments using laser induced breakdown and pulsed Raman spectroscopy, statistical analysis and light microscopy  

Science.gov (United States)

Pulsed laser induced breakdown spectroscopy (LIBS) and Raman spectroscopy were performed using a novel laboratory setup employing the same Nd:YAG laser emission at 532 nm for the analysis of five commercially available pigments collectively known as "ultramarine blue", a sodium silicate material of either mineral origin or an artificially produced glass. LIBS and Raman spectroscopy have provided information regarding the elemental and molecular composition of the samples; additionally, an analytical protocol for the differentiation between natural (lapis lazuli) and artificial ultramarine blue pigments is proposed. In particular LIBS analysis has allowed the discrimination between pigments on the basis of peaks ascribed to calcium. The presence of calcite in the natural blue pigments has been confirmed following Raman spectroscopy in specific areas of the samples, and micro-Raman and optical microscopy have further corroborated the presence of calcite inclusions in the samples of natural origin. Finally multivariate analysis of Laser induced breakdown spectra using principal component analysis (PCA) further enhanced the differentiation between natural and artificial ultramarine blue pigments.

Osticioli, I.; Mendes, N. F. C.; Nevin, A.; Gil, Francisco P. S. C.; Becucci, M.; Castellucci, E.

2009-08-01

207

Benchmark studies of induced radioactivity produced in LHC materials, part I: Specific activities  

International Nuclear Information System (INIS)

Samples of materials which will be used in the LHC machine for shielding and construction components were irradiated in the stray radiation field of the CERN-EU high-energy reference field facility. After irradiation, the specific activities induced in the various samples were analysed with a high-precision gamma spectrometer at various cooling times, allowing identification of isotopes with a wide range of half-lives. Furthermore, the irradiation experiment was simulated in detail with the FLUKA Monte Carlo code. A comparison of measured and calculated specific activities shows good agreement, supporting the use of FLUKA for estimating the level of induced activity in the LHC. (authors)

208

Induced polarisation and the assessment of sorption/diffusion at radioactive waste repository sites  

International Nuclear Information System (INIS)

Induced polarisation is a geophysical technique used in mineral exploration in search of metallic ore deposits. Clay minerals also polarise when subjected to an electric current, although the mechanism differs from that of metallic bodies, and involves, amongst other properties, the clay mineral species, the interlayer spacing of the clay, and the nature and abundance of mobile ions in the pore fluid. As a result, it was proposed that induced polarisation of clays could be used as a method for determining their permeability and diffusivity. The work carried out in developing experimental procedures, and evaluating the feasibility of the proposal is presented in this report. (author)

209

Benchmark Studies of Induced Radioactivity Produced in LHC Materials, Pt I: Remanent Dose Rates  

Energy Technology Data Exchange (ETDEWEB)

Samples of materials which will be used in the LHC machine for shielding and construction components were irradiated in the stray radiation field of the CERN-EU high-energy reference field facility. After irradiation, the specific activities induced in the various samples were analyzed with a high-precision gamma spectrometer at various cooling times, allowing identification of isotopes with a wide range of half-lives. Furthermore, the irradiation experiment was simulated in detail with the FLUKA Monte Carlo code. A comparison of measured and calculated specific activities shows good agreement, supporting the use of FLUKA for estimating the level of induced activity in the LHC.

Brugger, M.; Mayer, S.; Roesler, S.; Ulrici, L.; /CERN; Khater, H.; Prinz, A.; Vincke, H.; /SLAC

2006-04-12

210

Benchmark Studies of Induced Radioactivity Produced in LHC Materials, Pt I: Remanent Dose Rates  

International Nuclear Information System (INIS)

Samples of materials which will be used in the LHC machine for shielding and construction components were irradiated in the stray radiation field of the CERN-EU high-energy reference field facility. After irradiation, the specific activities induced in the various samples were analyzed with a high-precision gamma spectrometer at various cooling times, allowing identification of isotopes with a wide range of half-lives. Furthermore, the irradiation experiment was simulated in detail with the FLUKA Monte Carlo code. A comparison of measured and calculated specific activities shows good agreement, supporting the use of FLUKA for estimating the level of induced activity in the LHC

211

Effect of atropine and gammahydroxybutyrate on ischemically induced changes in the level of radioactivity in [3H]inositol phosphates in gerbil brain in vivo  

International Nuclear Information System (INIS)

Brain ischemia in gerbils was induced by ligation of both common carotid arteries for 1 min or 10 min. Sham-operated animals served as controls. Intracerebral injection of [3H]inositol into gerbil brain 16 hr before ischemic insult resulted in equilibration of the label between inositol lipids and water-soluble inositol phosphate. A short ischemic period (1 min) resulted in a statistically significant increase in the radioactivity of inositol triphosphate (IP3) and inositol monophosphate (IP), by about 48% and 79%, respectively, with little change in that of the intermediate inositol biphosphate (IP2), which increased by about 16%. When the ischemic period was prolonged (10 min), an increase in the radioactivity of inositol monophosphate exclusively, by about 84%, was observed. The level of radioactivity in inositol phosphates IP2 and IP3 decreased by about 50%, probably as a consequence of phosphatase activation by the ischemic insult. The agonist of the cholinergic receptor, carbachol, injected intracerebrally (40 micrograms per animal) increased accumulation of radioactivity in all inositol phosphates. The level of radioactivity in IP3, IP2, and IP was elevated by about 40, 23, and 147%, respectively. The muscarinic cholinergic antagonist, atropine, injected intraperitoneally in doses of 100 mg/kg body wt. depressed phosphoinositide metabolism in control animals. The level of radioactivity in water-soluble inositol metabolites in the brain of animals pretreated wittes in the brain of animals pretreated with atropine was evidently about 32% lower than in untreated animals. Pretreatment with atropine decreased the radioactivity of all inositol phosphates in the brain of animals subjected to 1-min ischemia and the radioactivity of IP in the case of 10-min brain ischemia

212

Osmosis-induced swelling of Eurobitum bituminized radioactive waste in constant total stress conditions  

Science.gov (United States)

In geological disposal conditions, contact of Eurobitum bituminized radioactive waste, which contains high amounts of the hygroscopic and highly soluble NaNO 3, with groundwater will result in water uptake and swelling of the waste, and in subsequent leaching of the embedded NaNO 3 and radionuclides. The swelling of and the NaNO 3 leaching from non-radioactive Eurobitum samples, comprised between two stainless steel filters and in contact with 0.1 M KOH, was studied in restricted (semi-confined) swelling conditions, i.e. under a constant total stress, or counterpressure, of 2.2, 3.3, or 4.4 MPa ( i.e. oedometer conditions). Four tests were stopped after hydration times between 800 and 1500 days, and the samples were analyzed by micro-focus X-ray Computer Tomography (?CT) and by Environmental Scanning Electron Microscopy (ESEM). The complete set of data enabled a consistent interpretation of the observations and lead to an improved understanding of the phenomenology of the water uptake, swelling, and NaNO 3 leaching in restricted swelling conditions. Under the studied conditions, the bituminous matrix surrounding the NaNO 3 crystals and pores with NaNO 3 solution behaved as a highly efficient semi-permeable membrane, i.e. osmotic processes occurred. In the main part of the leached layers, a high average NaNO 3 concentration and related to this a high osmotic pressure prevailed, explaining why in the studied range the swelling was not measurably affected by the counterpressure. At the interface with the stainless steel filters, a low permeable re-compressed bitumen layer was formed, contributing to the slow release of NaNO 3 compared to the water uptake rate. A fully coupled Chemo-Hydro-Mechanical (CHM) constitutive model has been developed that integrates the key processes involved and that reproduces satisfactorily the results; this is presented in another work. Combination of the experimental and the modelling study allow to conclude that under semi-confined conditions the swelling of the bituminized waste, and its evolution with time, is the result of several transient processes (salts dissolution, diffusion of salts and water, advection, creep, involving a low permeability material with evolving thickness and properties) that moreover are non-linear and strongly coupled.

Valcke, E.; Marien, A.; Smets, S.; Li, X.; Mokni, N.; Olivella, S.; Sillen, X.

2010-11-01

213

Prospective study in the management of high-dose radioactive iodine therapy induced gastritis  

International Nuclear Information System (INIS)

Full text: Gastritis is simply defined as inflammation of the gastric mucosa. In post-RAI patients, this is one of the most common complications that are encountered. Some patients may even require repetitive administration of high doses of radioactive iodine (I-131). Small doses of radiation (up to 1500 R) cause reversible mucosal damage, whereas higher radiation doses cause irreversible damage with atrophy and ischemic-related ulceration. Reversible changes consist of degenerative changes in epithelial cells and nonspecific chronic inflammatory infiltrate in the lamina propria. Higher amounts of radiation cause permanent mucosal damage, with atrophy of fundic glands, mucosal erosions, and capillary hemorrhage. Associated submucosal endarteritis results in mucosal ischemia and secondary ulcer development. Recurrent gastritis, if left untreated, may be a predisposing factor for gastric malignancy. Methods:A total of thirty post-RAI subjects were evaluated for signs and symptoms of gastritis and were divided into 3 groups which were given drugs for gastritis (H2-receptor antagonist, proton pump inhibitor, and sucralfate). Survey forms were distributed to evaluate the presence of nausea, vomiting, epigastric pain (graded according to severity of pain), and gastrointestinal bleeding. Results were tallied accordingly. Results and Discussion: In a total of 3 subjects who were given sucralfate, all of them did not experience any nausea and vomiting. One subject experienced sea and vomiting. One subject experienced mild epigastric discomfort and another subject was able to experience a non-specific symptom of abdominal bloatedness. (Note: Subjects are still for completion) In theory, radiation irritates the mucosa causing inflammation and mucosal damage which is further irritated by gastric acid secretion. The administration of H2-receptor blockers and proton pump inhibitors only inhibit gastric acid secretion while existing inflammation of mucosa due to high doses of radiation is left untreated. However, sucralfate may selectively bind to the damaged mucosa and act as a barrier to acid, pepsin and bile. Conclusion: Promising results are noted, however, completion of subjects is still warranted to further strengthen the study. Aside from being the most common complication of high dose and repetitive radioactive iodine administration, management of gastritis in post-RAI patients is valuable because of the possible sequelae of gastrointestinal bleeding and/or gastric malignancy. (author)

214

Characterization and comparison of seismic signals emitted during field scale sheer box experiments and artificially induced landslides  

Science.gov (United States)

The identification and detection of landslide induced seismic signals, recorded by deployed seismometers on active landslides has been the subject of many studies. The most commonly faced problem is the uncertainty in identifying which of the recorded signals are representing a movement or a failure in the landslide's body. In this paper we present two novel experimental campaigns; 1) field scale laboratory experiments of a 65cm diameter sheer box, 2) artificially induced failure of two, two-meter high vertical soil slopes. Using a field scale sheer box we recorded seismic signals emitted during soil slippage events, a phenomenon observed at a landslide's failure plain. This was implemented by displacing, a few centimeters at a time (1-10cm), a concrete cylinder filled with soil along a corridor free from vegetation. The field scale sheer box methodology allows control over a large number of parameters that affect a landslide. For example, it is possible to control soil saturation thus simulating different rain events or control the stress field on the soil's slippage surface simulating displacement events at different depths. More than 40 displacement events were induced under four different loading conditions between 472kg to 829kg. All soil slippage events were recorded above the levels of background seismic noise. Repetition of the methodology under the same experimental conditions resulted in similar seismic signals allowing us to define a 'characteristic seismic response' for soils. In the second experimental campaign, two controlled landslides were experimentally induced by increasing the vertical load on top of a 2m soil scarp. We were able to detect from 1 to 10 centimeter wide crack propagations and displacements, and approximately 20x20x10cm to 100x50x20cm block failure events based on microseismic recordings, field notes, video recordings and displacement measurements of the landslide's crown that failed during the experiments. Direct correlation between these visual recordings with seismic signals produced unique frequency patterns. Scanning all seismic data searching for these patterns allowed for detection of displacement events within the recordings that were not observed visually and were likely located within the landslide's mass. Both experimental campaigns were recorded by short period 3D seismic sensors. In order to validate the signals emitted using the sheer box methodology we compared them to the small displacement events recorded in the landslide experiments in the frequency domain by calculating their power spectral densities. Our results show close similarity between the two, validating the field scale lab experiment as a tool for preliminary understanding of the expected seismicity of an active landslide. Our study demonstrates the potential of microseismic motoring for detecting small soil displacements and soil block failures above ambient noise levels, as part of an active landslide monitoring campaign. Future research will use these results to design a monitoring network based on the threshold for event detection, which is a function of the displacement rate and the source-to-receiver distance. To our knowledge these are the first controlled field experiments that can allow validation and calibration of seismic monitoring for landslide detection.

Yfantis, Georgios; Martinez Carvajal, Hernan Eduardo; Pytharouli, Stella; Lunn, Rebecca

2014-05-01

215

Study of the artificial radioactivity of the marine medium using gamma spectrometry (1962-1966); Etude de la radioactivite artificielle du milieu marin par spectrometrie gamma (1962-1966)  

Energy Technology Data Exchange (ETDEWEB)

The results described in this study are relative to the artificial radioactivity of such elements as zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 and praseodymium-144 which were present in the atmospheric fallout between 1962 and 1964, and their incidence in superficial marine waters. Various physical, chemical or biological processes are studied by a high sensitivity gamma ray spectrometry technic, using those radioelements as 'tracers'. The change of state in sea water of an important fraction (about 50 per cent) of the radioactive particles going into the soluble phase - this phenomenon was not expected for those radioelements - controls the processes of accumulation in the planktonic biomass and the diffusion towards deeper waters. On the other hand, an 'in situ' spectrometry method is described. It enables the direct measurement in the sea of very low concentrations of some gamma ray emitters. The application of this method has made possible to carry out numerous observations in the surface waters of the Western Mediterranean sea and in the Bay of Biscay. It is shown that the mixing depth is closely connected to the depth of the thermocline. An accumulation process at this level is observed. The diffusion coefficients are similar to the thermal turbulent coefficient. The existence during several months of 'compartments' is established for the surface waters of the Bay of Biscay. From the establishment of the budget of fall-out, a comparative study shows that the rate of radioactive fallout on the maritime zone considered is always two to three times higher than on the neighbouring continental regions. Several explanations of this phenomenon are discussed. (author) [French] Les resultats decrits dans cette etude concernent la radioactivite artificielle sous forme de zirconium-95, niobium-95, ruthenium-103, ruthenium-106, cerium-141, cerium-144 et praseodyme-144 apportee par la retombee atmospherique entre 1962 et 1964 et les incidences de cette retombee dans les eaux marines superficielles. Considerant les radioelements etudies comme des 'traceurs' dans le milieu marin, divers processus physiques, chimiques ou biologiques ont ete etudies par spectrometrie gamma a haute sensibilite. Le passage en phase soluble dans l'eau de mer d'une fraction importante (environ 50 pour cent) de l'activite liee aux poussieres radioactives, phenomene qui n'etait pas previsible pour les radioelements etudies, gouverne les processus d'accumulation dans la biomasse planctonique et la diffusion vers les eaux plus profondes. Par ailleurs, une methode de spectrometrie 'in situ' permettant de mesurer directement dans la mer de tres faibles concentrations en certains radionuclides emetteurs gamma est decrite. L'application de cette methode a permis de nombreuses observations dans les eaux de surface de la Mediterranee occidentale et du Golfe de Gascogne. On montre quo la profondeur de melange est etroitement liee a celle de la thermocline. Un processus d'accumulation au niveau de celle-ci est constate. Les coefficients de diffusion sont voisins du coefficient de diffusion thermique turbulente. L'existence de compartiments qui subsistent pendant plusieurs mois dans la masse des eaux de surface du Golfe de Gascogne est mise en evidence. Grace aux bilans effectues, une etude comparative montre que le taux de retombees radioactives sur les surfaces maritimes est toujours deux a trois fois superieur a celui sur les regions continentales voisines. Diverses explications de ce phenomene sont discutees. (auteur)

Chesselet, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

216

Development of the precise measurement method for gamma-ray energy of neutron induced radioactive nuclides  

International Nuclear Information System (INIS)

Goal of the research is to develop a new energy calibration method to perform precise measurement of photon energy by gamma-ray spectrometry. Here, we regard reference standard energies to be those of photon of radioactive isotopes measured basing on a laser wavelength of 86Kr (606 nm) together with energy-wavelength conversion factor E? = 1.239 842 44 x 10-6 eV m ±0.03 ppm (CODATA 1986). As such the reference standard we use 192Ir isotope. Deviation of photon energy values between data obtained by photon spectrometry, i.e., the decay gamma-ray analysis and the prompt gamma-ray analysis with Ge or Ge(Li) detectors, and those obtained by crystal diffraction spectrometry, has led that the 'conventional' method of energy calibration for the photon spectrometry is not adequate to the precise energy assignment. A 'new' method has solved this problem by introducing the concept of an instrument function, which is the transfer function between an input signal-shape function and an output (measured) signal-shape function, as summarized in reference 1. Present status of photon energy values has been examined for the nuclear-decay gamma-rays, the nuclear excitation gamma-rays and the mesonic-atom X-rays. At the previous stage of research we evaluated that a commonly-used internal standard method, mainly used for activation analysis study, was inadequate for the precise measurement of photon energy, so far as we use base subtraction method. In the present study, we examined the cause of the inadequacy of a base-subtraction method for obtaining the photopeak line shape for the precise energy measurement. (author)

217

A fast method for the calculation of electron number density and temperature in laser-induced breakdown spectroscopy plasmas using artificial neural networks  

Science.gov (United States)

A fast and precise method for the determination of electron temperature and electron number density in laser-induced plasmas is presented. The method is based on the use of a simple artificial neural network (ANN), trained on a suitable set of laser-induced breakdown spectroscopy spectra. The training procedure is quite fast; once the ANN is set, the determination of plasma temperature and electron number density is almost instantaneous, allowing the possibility of measuring these parameters, with good precision, in real time. A direct application of this new method could be the characterization of plasmas generated during pulsed laser deposition process of thin films and nanoparticles generation. The plasma electronic parameters will help to tune the energies involved in the stoichiometry and crystallization control of those nanostructured materials. As an example, the characteristics of the plasma induced by a Nd:YAG laser on a pure titanium target are determined, at different laser fluences.

Borges, Fábio O.; Cavalcanti, Gildo H.; Gomes, Gabriela C.; Palleschi, Vincenzo; Mello, Alexandre

2014-10-01

218

Thermally induced motion of marine sediments resulting from disposal of radioactive wastes  

International Nuclear Information System (INIS)

Coupled creep and heat transfer calculations have been performed to assess the sensitivity of heat load, viscosity, and canister density on the motion of waste canisters buried in marine sediments. Results indicate that no upward movement is predicted for heat loads remaining within the metallurgical and geochemical constraints placed on the temperature of sediments near the canister for the times analyzed. Upward movement of the canister is again not observed in calculations involving reasonable variations of the sediment viscosity and canister density. Maximum effective deviatoric stress levels due to thermally induced differential body forces are significantly less than the sediment's short term peak strength

219

Induced radioactivity of materials by stray radiation fields at an electron accelerator  

CERN Document Server

Samples of soil, water, aluminum, copper and iron were irradiated in the stray radiation field generated by the interaction of a 28.5 GeV electron beam in a copper-dump in the Beam Dump East facility at the Stanford Linear Accelerator Center. The specific activity induced in the samples was measured by gamma spectroscopy and other techniques. In addition, the isotope production in the samples was calculated with detailed Monte Carlo simulations using the FLUKA code. The calculated activities are compared to the experimental values and differences are discussed.

Rokni, S H; Gwise, T; Liu, J C; Roesler, S

2002-01-01

220

THE INTEGRAL ESTIMATION OF PERCEIVED DISCOMFORT CONDITION OF THE URANIUM PROCESSING ENTERPRISE EMPLOYEES AND CITY RESIDENTS WITH ARTIFICIALLY INCREASED NATURAL SOURCE OF RADIOACTIVITY  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction. After the Chernobyl accident radio-anxiety of the population remains one of the most acute psychosocial problems in Ukraine, especially in the regions where uranium is extracted and processed. Uranium raw material – basis of nuclear fuel for nuclear energy – has been processed in Zhovti Vody of Dnipropetrovsk region since 1950s. Zhovti Vody is a unique place. The city is surrounded with the uranium production facilities: the hydrometallurgical factory and the uranium waste tailing damp. Purpose. Our aim was to estimate perceived health status of Zhovti Vody citizens (population category «?» and the employees of the industrial complex «Eastern Mining Processing Plant» (MPP, who work with radiation sources daily (categories «A» and «B». Materials and Methods. We checked the health status of average Zhovti Vody citizens (102 and industrial complex employees (104, who work with radiation sources daily. The samplings deferred only by the place of employment of respondents. The average age of respondents (M ± m was 41.6 ± 0.9 years. The gender (? > 0.9 and age (? > 0.7 characteristics were similar for both groups. The applied research methods were developed and tested by the specialists of V. M. Bekhterev Psychoneurological Research Institute (Saint Petersburg. Discussion 1. According to the integral estimation of the perceived discomfort condition: the employees complained less of pain, but citizens who did not work in the industrial complex complained more. 2. Mental health of the population corresponds to the low (by anxiety and frustration indices and middle assessment levels (on the constriction and aggressiveness scales. However, the employees of the industrial complex showed the lower degree of symptom expression. 3. The majority of population (88.3 % showed the low level of social frustration regardless to the place of employment. 4. The correlation between physical and mental health statuses (anxiety, constriction, psychological and social frustration confirmed interaction between pain and psychological symptoms. The employees of the industrial complex showed better estimation of perceived health status comparing with citizens, who work in other institutions. Thus, the employees of any industrial complexes normally express less radio-anxiety, because they work with radioactive sources daily.

Shevchenko ?. A.

2014-03-01

221

An active artificial cornea with the function of inducing new corneal tissue generation in vivo-a new approach to corneal tissue engineering  

International Nuclear Information System (INIS)

An active artificial cornea which can perform the function of inducing new cornea generation in vivo but does not need culture cells in vitro and which has similar optical and mechanical properties to those of the human cornea was constructed. An animal keratoplasty experiment using the artificial cornea as the implant showed that the animals' corneas could keep smooth surface and clear stroma postoperatively, and that the repopulation of the host's keratocytes, the degradation of the implant and new corneal tissue generation were completed at 5-6 months after surgery. Such an artificial cornea has several advantages over other corneal equivalents constructed in the typical way of tissue engineering: in having similar mechanical and optical properties to those of the human cornea and with no exogenetic cells, it can be used universally in different implantation surgeries without immunoreaction; it is easy to prepare and process into different shapes and sizes on a large scale, and suitable for long-distance transportation and long-term storage. All these characteristics make it a new approach to cornea tissue engineering having potential in many clinical applications

222

Henry Becquerel, Pierre and Marie Curie and radioactivity: background, circumstances and implication of the founder discoveries  

International Nuclear Information System (INIS)

After Roentgen's X-rays discovery in 1895, Henry Becquerel discovers a proper radiation of uranium. Then, Pierre and Marie Curie discover polonium and radium. They establish that some atoms may produce spontaneously energy under radiations form which may lead to induce radioactivity. The essential interpretation was done by Rutherford with the distinction of alpha, beta and gamma radiations, and the atomic model of Rutherford-Bohr. The first transmutations under radiations effects lead to the neutrons discovery by Bothe and Becker, Irene Curie and Frederic Joliot, and to the interpretation by Chadwick, the artificial radioactivity of phosphorous by I. Curie and F. Joliot, and to the fission. (A.B.). 7 photos

223

Comparison of different radioactive renal agents in cisplatin-induced tubular toxicity in rats  

International Nuclear Information System (INIS)

The efficacy of five different radiodiagnostic agents for detecting renal tubular dysfunction induced with cisplatin in rats was compared to controls. Diethylenetriaminepentaacetic acid (DTPA) labeled with 99mTc or 111In was administered simultaneously with each of the other four agents [99mTc]glucoheptonate, [99mTc]dimercaptosuccinic acid, [131I]hippuran and [111In]lysozyme as a standard to normalize for differences in functional impairment from animal to animal from the same dose of cisplatin. The 2-hr plasma clearance and computer-generated 2- to 3-min uptake in the two kidneys with [99mTc]dimercaptosuccinic acid were significantly inferior to similar measurements with the other agents in differentiating abnormal from normal function. The 2-hr uptake of [99mTc]glucoheptonate and [111In]lysozyme proved of no value in this differentiation. The late renal retention of [99mTc]dimercaptosuccinic acid well separated the cisplatin from control rats, but the greatest difference was observed by the 2-hr uptakes of [131I]hippuran and DTPA

224

Comparison of different radioactive renal agents in cisplatin-induced tubular toxicity in rats  

Energy Technology Data Exchange (ETDEWEB)

The efficacy of five different radiodiagnostic agents for detecting renal tubular dysfunction induced with cisplatin in rats was compared to controls. Diethylenetriaminepentaacetic acid (DTPA) labeled with /sup 99m/Tc or /sup 111/In was administered simultaneously with each of the other four agents (/sup 99m/Tc)glucoheptonate, (/sup 99m/Tc)dimercaptosuccinic acid, (/sup 131/I)hippuran and (/sup 111/In)lysozyme as a standard to normalize for differences in functional impairment from animal to animal from the same dose of cisplatin. The 2-hr plasma clearance and computer-generated 2- to 3-min uptake in the two kidneys with (/sup 99m/Tc)dimercaptosuccinic acid were significantly inferior to similar measurements with the other agents in differentiating abnormal from normal function. The 2-hr uptake of (/sup 99m/Tc)glucoheptonate and (/sup 111/In)lysozyme proved of no value in this differentiation. The late renal retention of (/sup 99m/Tc)dimercaptosuccinic acid well separated the cisplatin from control rats, but the greatest difference was observed by the 2-hr uptakes of (/sup 131/I)hippuran and DTPA.

McAfee, J.G.; Subramanian, G.; Thomas, F.D.; Hellwig, B.; Roskopf, M.

1989-05-01

225

Artificial Intelligence.  

Science.gov (United States)

A series of articles focuses on artificial intelligence research and development to enhance information systems and services. Topics discussed include knowledge base designs, expert system development tools, natural language processing, expert systems for reference services, and the role that artificial intelligence concepts should have in…

Smith, Linda C.; And Others

1988-01-01

226

Artificial blood  

Directory of Open Access Journals (Sweden)

Full Text Available Artificial blood is a product made to act as a substitute for red blood cells. While true blood serves many different functions, artificial blood is designed for the sole purpose of transporting oxygen and carbon dioxide throughout the body. Depending on the type of artificial blood, it can be produced in different ways using synthetic production, chemical isolation, or recombinant biochemical technology. Development of the first blood substitutes dates back to the early 1600s, and the search for the ideal blood substitute continues. Various manufacturers have products in clinical trials; however, no truly safe and effective artificial blood product is currently marketed. It is anticipated that when an artificial blood product is available, it will have annual sales of over $7.6 billion in the United States alone.

Sarkar Suman

2008-01-01

227

Artificial neural network modeling of healthy risk level induced by aircraft pollutant impacts around Soekarno Hatta International Airport  

OpenAIRE

Aircraft pollutant emissions are an important part of sources of pollution that directly or indirectly affect human health and ecosystems. This research suggests an Artificial Neural Network model to determine the healthy risk level around Soekarno Hatta International Airport-Cengkareng Indonesia. This ANN modeling is a flexible method, which enables to recognize highly complex non-linear correlations. The network was trained with real measurement data and updated with new measurements, enha...

Salah Khardi; Jermanto Setia Kurniawan; Irwan Katili; Setyo Moersidik

2013-01-01

228

Ablation from artificial or laser-induced crater surfaces of silver by laser irradiation at 355 nm  

DEFF Research Database (Denmark)

The angular distribution of laser ablated particles from silver irradiated at 355 nm has been studied. The angular distribution from craters prepared by more than 10(4) shots exhibits only minor changes compared with that from a nonirradiated target. The distribution from artificial cylindrical craters of a depth comparable to the laser spot dimensions is about one order of magnitude smaller at large exit angles than that from a flat target.

Toftmann, B.; Schou, JØrgen

1999-01-01

229

Artificial sunlight and ultraviolet light induced photo-epoxidation of propylene over V-Ti/MCM-41 photocatalyst  

Science.gov (United States)

Summary The light irradiation parameters, including the wavelength spectrum and intensity of light source, can significantly influence a photocatalytic reaction. This study examines the propylene photo-epoxidation over V-Ti/MCM-41 photocatalyst by using artificial sunlight (Xe lamp with/without an Air Mass 1.5 Global Filter at 1.6/18.5 mW·cm?2) and ultraviolet light (Mercury Arc lamp with different filters in the range of 0.1–0.8 mW·cm?2). This is the first report of using artificial sunlight to drive the photo-epoxidation of propylene. Over V-Ti/MCM-41 photocatalyst, the propylene oxide (PO) formation rate is 193.0 and 112.1 µmol·gcat ?1·h?1 with a PO selectivity of 35.0 and 53.7% under UV light and artificial sunlight, respectively. A normalized light utilization (NLU) index is defined and found to correlate well with the rate of both PO formation and C3H6 consumption in log–log scale. The light utilization with a mercury arc lamp is better than with a xenon lamp. The selectivity to PO remains practically unchanged with respect to NLU, suggesting that the photo-epoxidation occurs through the same mechanism under the conditions tested in this study. PMID:24991493

Nguyen, Van-Huy; Bai, Hsunling

2014-01-01

230

Artificial urushi.  

Science.gov (United States)

A new concept for the design and laccase-catalyzed preparation of "artificial urushi" from new urushiol analogues is described. The curing proceeded under mild reaction conditions to produce the very hard cross-linked film (artificial urushi) with a high gloss surface. A new cross-linkable polyphenol was synthesized by oxidative polymerization of cardanol, a phenol derivative from cashew-nut-shell liquid, by enzyme-related catalysts. The polyphenol was readily cured to produce the film (also artificial urushi) showing excellent dynamic viscoelasticity. PMID:11763444

Kobayashi, S; Uyama, H; Ikeda, R

2001-11-19

231

Experimental studies on the neutron emission spectrum and induced radioactivity of the sup 7 Li(d,n) reaction in the 20-40 MeV region  

CERN Document Server

To improve the data accuracy of the neutron emission spectrum of the sup 7 Li(d,n) reaction and the radioactivity ( sup 7 Be, sup 3 H, etc.) accumulated in the sup 7 Li target in IFMIF, we have measured the neutron emission spectrum and the radioactivity of sup 7 Be induced in the lithium target for 25 MeV deuterons at the Tohoku University AVF cyclotron (K=110) facility. Neutron spectra were measured with the time-of-flight (TOF) method at four laboratory angles by using a beam swinger system and a well collimated TOF channel. Induced radioactivity was measured by detecting the gamma-rays from sup 7 Be with a pure Ge detector. Experimental results are compared with other experimental data. The present result of neutron emission spectra are in qualitative agreement with other experimental data but that of sup 7 Be production was much larger than expected by the recent codes. Measurement will be extended to several incident energies up to 40 MeV.

Baba, M; Hagiwara, M; Sugimoto, M; Miura, T; Kawata, N; Yamadera, A; Orihara, H

2002-01-01

232

Experimental studies on the neutron emission spectrum and induced radioactivity of the 7Li(d,n) reaction in the 20-40 MeV region  

Science.gov (United States)

To improve the data accuracy of the neutron emission spectrum of the 7Li(d,n) reaction and the radioactivity ( 7Be, 3H, etc.) accumulated in the 7Li target in IFMIF, we have measured the neutron emission spectrum and the radioactivity of 7Be induced in the lithium target for 25 MeV deuterons at the Tohoku University AVF cyclotron ( K=110) facility. Neutron spectra were measured with the time-of-flight (TOF) method at four laboratory angles by using a beam swinger system and a well collimated TOF channel. Induced radioactivity was measured by detecting the gamma-rays from 7Be with a pure Ge detector. Experimental results are compared with other experimental data. The present result of neutron emission spectra are in qualitative agreement with other experimental data but that of 7Be production was much larger than expected by the recent codes. Measurement will be extended to several incident energies up to 40 MeV.

Baba, M.; Aoki, T.; Hagiwara, M.; Sugimoto, M.; Miura, T.; Kawata, N.; Yamadera, A.; Orihara, H.

2002-12-01

233

Inhibition of BmNPV replication in silkworm cells using inducible and regulated artificial microRNA precursors targeting the essential viral gene lef-11.  

Science.gov (United States)

Bombyx mori nucleopolyhedrovirus (BmNPV) is a major silkworm pathogen, causing substantial economic losses to the sericulture industry annually. We demonstrate a novel anti-BmNPV system expressing mature artificial microRNAs (amiRNAs) targeting the viral lef-11 gene. The mature amiRNAs inhibited the lef-11 gene in silkworm BmN-SWU1 cells. Antiviral assays demonstrated that mature amiRNAs silenced the gene and inhibited BmNPV proliferation efficiently. As constitutive overexpression of mature amiRNAs may induce acute cellular toxicity, we further developed a novel virus-induced amiRNA expression system. The amiRNA cassette is regulated by a baculovirus-induced fusion promoter. This baculovirus-induced RNA interference system is strictly regulated by virus infection, which functions in a negative feedback loop to activate the expression of mature amiRNAs against lef-11 and subsequently control inhibition of BmNPV replication. Our study advances the use of a regulatable amiRNA cassette as a safe and effective tool for research of basic insect biology and antiviral application. PMID:24486953

Zhang, Jun; He, Qian; Zhang, Chun-Dong; Chen, Xiang-Yun; Chen, Xue-Mei; Dong, Zhan-Qi; Li, Na; Kuang, Xiu-Xiu; Cao, Ming-Ya; Lu, Cheng; Pan, Min-Hui

2014-04-01

234

Ambient radioactivity levels and radiation doses. Annual report 2012; Umweltradioaktivitaet und Strahlenbelastung. Jahresbreicht 2012  

Energy Technology Data Exchange (ETDEWEB)

The annual report 2012 on ambient radioactivity levels and radiation doses covers the following issues: Part A: General information: natural environmental radioactivity; artificial radioactivity in the environment; occupational radiation exposure; radiation exposures from medical applications; the handling of radioactive materials and sources of ionizing radiation; non-ionizing radiation. Part B: Current data and their evaluation: natural environmental radioactivity; artificial radioactivity in the environment; occupational radiation exposures; radiation exposures from medical applications; the handling of radioactive materials and sources of ionizing radiation; non-ionizing radiation. The report includes data on the stock of radioactive waste, radiation accidents and unusual events.

Bernhard-Stroel, Claudia; Hachenberger, Claudia; Trugenberger-Schnabel, Angela; Loebke-Reinl, Angelika; Peter, Josef (comps.) [Bundesamt fuer Strahlenschutz, Salzgitter (Germany)

2014-06-15

235

Environmental radioactivity in the antarctic station  

International Nuclear Information System (INIS)

Study about environmental radioactivity in the Peruvian antarctic station Machu Pichu they were carried out during the last three periods to the southern summer. The objective of the project it is to evaluate environmental component in order to elaborate a study it base on the levels background radioactivity and artificial in the antarctic region

236

Decontamination of radioactive cesium in soil  

International Nuclear Information System (INIS)

Agricultural soil containing radioactive cesium was decontaminated using an extraction method involving aqueous potassium solutions. Results demonstrated that the potassium solution could extract radioactive cesium from soil artificially contaminated with 137Cs, although extraction rate decreased as time after contamination increased. However, visual examination of radioactivity distribution in soil samples significantly contaminated by the accident at the Fukushima Daiichi nuclear power plant showed that radioactive cesium also existed as insoluble particles. Therefore, reducing the volume of radioactive wastes generated from soil decontamination requires a physical decontamination method combined with chemical treatment. (author)

237

From meandering to straight grain boundaries: Improving the structures of artificially-induced grain boundaries in superconducting YBa2Cu3Oy bicrystals  

International Nuclear Information System (INIS)

This paper presents several key aspects of the successful approach to preparing artificially-induced [001] tilt YBa2Cu3Oy (YBCO) grain boundaries (GBs) with uniform, well-defined structures. The authors have compared the structure of GBs produced in thin film bicrystals and bulk bicrystals, respectively. In the YBCO thin film bicrystals prepared by off-axis magnetron sputtering, meandering rather than planar GBs were generally formed due to the three-dimensional island-shaped nucleation and growth of the thin films. Experimentally, using a low film deposition rate has been demonstrated to reduce the magnitude of meander. However, complete elimination of the meandering configuration has not yet been accomplished due to the film growth mechanism. Thus, the authors have developed a dual-seeded-melt-texture process to produce uniform, planar GBs in [001] tilt YBCO bulk bicrystals. Transmission electron microscopy (TEM) studies revealed GBs with a remarkably planar configuration on both micro and nano-meter scales, demonstrating that simpler, meander-free GB microstructures with well defined [001] tilt angle have been successfully produced compared to those formed in bicrystal thin films. The high reproducibility, excellent stability and well controlled GB orientations have established the dual-seeded-melt-texture process as a reliable technique for engineering artificial GBs for the purpose of systematic studies of GB properties and allow for more insightful measurements of transport properties across individual GBs

238

Natural and artificial radioactivity in the environment  

International Nuclear Information System (INIS)

Several authors analyse the processes, which occurred during and after the reactor accident at Chernobyl. Interactions and correlations are explained in a way easy to understand. In addition, other authors deal with issues of exposure to natural radiation from the earth's crust, from the atmosphere and outer space, and with their impacts on living organisms. In conclusion, one author evaluates the reactor accident and its consequences for society from the churches' point of view. 8 abstracts were entered separately into the data base. (DG)

239

Artificial radioactive tracers: a tool for oceanography  

International Nuclear Information System (INIS)

In marine hydrodynamic, use of 125Sb as tracer and a two stages coprecipitation analysis process allows to study water motion in the Channel and in the seas of the north east of Europe from effluents of La Hague (France) reprocessing plant. Other tracers may be used: 137Cs coming principally from Sellafield (United Kingdom), and 134Cs coming from Chernobyl accident. (A.B.). 15 refs., 8 figs., 5 tabs

240

Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer The water uptake by Eurobitum is studied to judge the safety of geological disposal. Black-Right-Pointing-Pointer High pressures of up to 20 MPa are measured in constant volume water uptake tests. Black-Right-Pointing-Pointer The morphology of leached Eurobitum samples is studied with {mu}CT and ESEM. Black-Right-Pointing-Pointer The observations are reproduced by an existing CHM formulation for Eurobitum. - Abstract: The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at Belgian Nuclear Research Center SCK-CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluna, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO{sub 3} leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography ({mu}CT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO{sub 3} solution. After about four years of hydration in nearly constant volume water uptake tests, pressures up to 20 MPa are measured. During this hydration period only the outer layers with a thickness of 1-2 mm were hydrated (as derived from {mu}CT and ESEM analyses), and only about 10-20% of the initial NaNO{sub 3} content was released by the samples. In the studied test conditions, the rates of water uptake and NaNO{sub 3} leaching are low because of the low porosity, and thus low permeability, of the hydrated BW samples in combination with a highly efficient semi-permeable bitumen membrane. In contrast to the hydration in free swelling conditions, the increase in porosity is limited by the high pressures in the nearly constant volume tests. Furthermore, at the interface with the stainless steel filters, a low permeable re-compressed bitumen layer is formed, as observed on the ESEM images. The experimental results of pressure increase and NaNO{sub 3} leaching, as well as observations on {mu}CT and ESEM images (e.g. compression of leached layers, high dissolved NaNO{sub 3} concentration in hydrated BW after about four years), were reproduced rather successfully by the coupled CHM formulation for Eurobitum BW. A long-term model prediction of the evolution of the osmosis-induced pressure in the nearly constant volume tests shows that the pressure would reach a maximal value of about 20 MPa after about 5.5 years, after which the pressure would start to decrease. After 10,000 days ({approx}27 years) the pressure would have decreased to a value of {approx}2 MPa.

Marieen, A., E-mail: amarien@sckcen.be [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Mokni, N., E-mail: Nadia.mokni@upc.edu [Department of Geotechnical Engineering and Geosciences, Universidad Politecnica de Catalunya (UPC), Calle Gran Capitan, s/n, Edificio C-1, 08034 Barcelona (Spain); Valcke, E. [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Olivella, S. [Department of Geotechnical Engineering and Geosciences, Universidad Politecnica de Catalunya (UPC), Calle Gran Capitan, s/n, Edificio C-1, 08034 Barcelona (Spain); Smets, S. [Waste and Disposal Expert Group, Belgian Nuclear Research Centre (SCK-CEN), Boeretang 200, 2400 Mol (Belgium); Li, X., E-mail: xli@sckcen.be [EIG EURIDICE, Boeretang 200, 2400 Mol (Belgium)

2013-01-15

241

Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions  

International Nuclear Information System (INIS)

Highlights: ? The water uptake by Eurobitum is studied to judge the safety of geological disposal. ? High pressures of up to 20 MPa are measured in constant volume water uptake tests. ? The morphology of leached Eurobitum samples is studied with ?CT and ESEM. ? The observations are reproduced by an existing CHM formulation for Eurobitum. - Abstract: The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at Belgian Nuclear Research Center SCK-CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluña, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO3 leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography (?CT) and Environmental Scanning Electron Miironmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO3 solution. After about four years of hydration in nearly constant volume water uptake tests, pressures up to 20 MPa are measured. During this hydration period only the outer layers with a thickness of 1–2 mm were hydrated (as derived from ?CT and ESEM analyses), and only about 10–20% of the initial NaNO3 content was released by the samples. In the studied test conditions, the rates of water uptake and NaNO3 leaching are low because of the low porosity, and thus low permeability, of the hydrated BW samples in combination with a highly efficient semi-permeable bitumen membrane. In contrast to the hydration in free swelling conditions, the increase in porosity is limited by the high pressures in the nearly constant volume tests. Furthermore, at the interface with the stainless steel filters, a low permeable re-compressed bitumen layer is formed, as observed on the ESEM images. The experimental results of pressure increase and NaNO3 leaching, as well as observations on ?CT and ESEM images (e.g. compression of leached layers, high dissolved NaNO3 concentration in hydrated BW after about four years), were reproduced rather successfully by the coupled CHM formulation for Eurobitum BW. A long-term model prediction of the evolution of the osmosis-induced pressure in the nearly constant volume tests shows that the pressure would reach a maximal value of about 20 MPa after about 5.5 years, after which the pressure would start to decrease. After 10,000 days (?27 years) the pressure would have decreased to a value of ?2 MPa.

242

Osmosis-induced water uptake by Eurobitum bituminized radioactive waste and pressure development in constant volume conditions  

Science.gov (United States)

The chemo-hydro-mechanical (CHM) interaction between swelling Eurobitum radioactive bituminized waste (BW) and Boom Clay is investigated to assess the feasibility of geological disposal for the long-term management of this waste. These so-called compatibility studies include laboratory water uptake tests at the Belgian Nuclear Research Center SCK•CEN, and the development of a coupled CHM formulation for Eurobitum by the International Center for Numerical Methods and Engineering (CIMNE, Polytechnical University of Cataluña, Spain). In the water uptake tests, the osmosis-induced swelling, pressure increase and NaNO3 leaching of small cylindrical BW samples (diameter 38 mm, height 10 mm) is studied under constant total stress conditions and nearly constant volume conditions; the actual geological disposal conditions should be intermediate between these extremes. Two nearly constant volume tests were stopped after 1036 and 1555 days to characterize the morphology of the hydrated BW samples and to visualize the hydrated part with microfocus X-ray Computer Tomography (?CT) and Environmental Scanning Electron Microscopy (ESEM). In parallel, a coupled CHM formulation is developed that describes chemically and hydraulically coupled flow processes in porous materials with salt crystals, and that incorporates a porosity dependent membrane efficiency, permeability and diffusivity. When Eurobitum BW is hydrated in (nearly) constant volume conditions, the osmosis-induced water uptake results in an increasing pressure to values that can be (in theory) as high as 42.8 MPa, being the osmotic pressure of a saturated NaNO3 solution. After about four years of hydration in nearly constant volume water uptake tests, pressures up to 20 MPa are measured. During this hydration period only the outer layers with a thickness of 1-2 mm were hydrated (as derived from ?CT and ESEM analyses), and only about 10-20% of the initial NaNO3 content was released by the samples. In the studied test conditions, the rates of water uptake and NaNO3 leaching are low because of the low porosity, and thus low permeability, of the hydrated BW samples in combination with a highly efficient semi-permeable bitumen membrane. In contrast to the hydration in free swelling conditions, the increase in porosity is limited by the high pressures in the nearly constant volume tests. Furthermore, at the interface with the stainless steel filters, a low permeable re-compressed bitumen layer is formed, as observed on the ESEM images. The experimental results of pressure increase and NaNO3 leaching, as well as observations on ?CT and ESEM images (e.g. compression of leached layers, high dissolved NaNO3 concentration in hydrated BW after about four years), were reproduced rather successfully by the coupled CHM formulation for Eurobitum BW. A long-term model prediction of the evolution of the osmosis-induced pressure in the nearly constant volume tests shows that the pressure would reach a maximal value of about 20 MPa after about 5.5 years, after which the pressure would start to decrease. After 10,000 days (˜27 years) the pressure would have decreased to a value of ˜2 MPa.

Mariën, A.; Mokni, N.; Valcke, E.; Olivella, S.; Smets, S.; Li, X.

2013-01-01

243

Fast identification of biominerals by means of stand-off laser-induced breakdown spectroscopy using linear discriminant analysis and artificial neural networks  

Science.gov (United States)

The goal of this paper is to compare two selected statistical techniques used for identification of archeological materials merely on the base of their spectra obtained by stand-off laser-induced breakdown spectroscopy (stand-off LIBS). Data processing using linear discriminant analysis (LDA) and artificial neural networks (ANN) were applied on spectra of 18 different samples, some of them archeological and some recent, containing 7 types of material (i.e. shells, mortar, bricks, soil pellets, ceramic, teeth and bones). As the input data PCA scores were taken. The intended aim of this work is to create a database for simple and fast identification of archeological or paleontological materials in situ. This approach can speed up and simplify the sampling process during archeological excavations that nowadays tend to be quite damaging and time-consuming.

Vítková, Gabriela; Novotný, Karel; Prokeš, Lubomír; Hrdli?ka, Aleš; Kaiser, Jozef; Novotný, Jan; Malina, Radomír; Prochazka, David

2012-07-01

244

From meandering to straight grain boundaries: Improving the structures of artificially induced grain boundaries in superconducting YBa2Cu3Oy bicrystals  

International Nuclear Information System (INIS)

This paper presents several key aspects of our approach to preparing artificially induced [001] tilt grain boundaries (GB close-quote s) with uniform, well-defined structures in YBa2Cu3Oy (YBCO) superconductors. GB structures formed in thin film and bulk bicrystals, respectively, will be compared. In YBCO thin film bicrystals, meandering rather than planar GB close-quote s are formed. Using a low film deposition rate has been demonstrated to reduce the magnitude of meander significantly, but complete elimination of the meander has not yet been accomplished. Thus, we have developed a dual-seeded-melt-texture process to produce uniform, planar GB close-quote s with controllable misorientation angles in YBCO bulk bicrystals. Transmission electron microscopy (TEM) studies reveal a remarkably planar and simple configuration on different length scales. Such a simple structure allows for an insightful interpretation of transport behavior across individual GB close-quote s. copyright 1997 Materials Research Society

245

Artificial Blood  

Directory of Open Access Journals (Sweden)

Full Text Available The problems and additional cost factor involved in collecting and storing human blood, as well as the pending worldwide shortages are the main driving forces in the development of blood substitutes. Studies on artificial blood basically aim to develop oxygen carrying compounds, produce stem cell-based erythrocyte cells in vitro and, implement the functions and movements of natural hemoglobin molecules found in erythrocyte cells through artificial erythrocyte cells. Consequently, major areas of research in artificial blood studies are haemoglobin-based oxygen carriers, perfluorochemicals, respirocytes and stem cells. Even though these artificial erythrocyte cells do not qualify as perfect red blood cell substitutes yet, they have many potential clinical and non clinical uses. Studies are being carried out on the elimination of side effects of blood substitutes and extensive clinical trials are being conducted to test their safety and efficacy. Artificial blood substitutes could only be used clinically for patient management following clinical trials and approvals, and will be the ultimate global solution to the problems associated with donor scarcity, blood collection and transfusion-mediated diseases. [Archives Medical Review Journal 2012; 21(2.000: 95-108

Umit Yasar

2012-04-01

246

Factors influencing pregnancy per artificial insemination in repeat-breeder cows induced to ovulate with a CIDR-based protocol.  

Science.gov (United States)

The aim of this study was to determine, using multiple logistic models, factors affecting pregnancy per AI (P/AI) following fixed-time artificial insemination (FTAI) in repeat breeders cows (RBC) treated with rbST throughout lactation. 498 RBC received a CIDR device and 100?g of GnRH on day 0. CIDR removal and PGF(2?) (25mg) treatment were done concurrently on day 7. Estradiol benzoate (EB, 1mg) was injected on day 8 and GnRH on day 9; cows were inseminated 16-20h later. Cows with an average milk protein milk protein ?3%. Cows with milk yields lower than 55kg were 1.5 times more likely to get pregnant than cows with peak milk yields greater than 55kg (P/AI 37 vs. 28%; Pmilk protein, increased service, increased lactation, high THI at AI and short dry periods. PMID:22917878

Mellado, M; Zuñiga, A; Veliz, F G; de Santiago, A; Garcia, J E; Mellado, J

2012-10-01

247

Risk methodology for geologic disposal of radioactive waste: a distribution-free approach to inducing rank correlation among input variables for simulation studies  

International Nuclear Information System (INIS)

A method for inducing a desired rank correlation matrix on a multivariate input random variable is introduced in this paper. This method is simple to use, is distribution free, preserves the exact form of the marginal distributions on the input variables, and may be used with any type of sampling scheme for which correlation of input variables is a meaningful concept. A small simulation study provides an estimate of the bias and variability involved in the method. Input variables used in a model for study of geologic disposal of radioactive waste provide an example of the usefulness of this procedure

248

Analysis of induced-radioactivity using DCHAIN-SP for iron, copper and niobium at a mercury target irradiated by 2.83 and 24 GeV protons  

International Nuclear Information System (INIS)

Reliability estimation was carried out on a radioactivity calculation code system consisting of PHITS, MCNP/4C and DCHAIN-SP 2001 by analyzing an activation experiment performed by using AGS (Alternative Gradient Synchrotron) accelerator at Brookhaven National Laboratory. For induced radioactivity in iron, copper and niobium samples, calculations and experiments were compared indicating that both agreed by a factor of 2 on the average over produced nuclides although the calculation had a tendency to underestimate. (author)

249

Geochemical ways of artificial radionuclide migration in biosphere  

International Nuclear Information System (INIS)

The collection contains abstracts of papers concerning aspects of distribution, forms and migration of artificial radionuclides in biosphere, simulation of their behaviour in separate components and systems. Methods of radioactivity monitoring in biosphere are discussed

250

Artificial Sweeteners  

Science.gov (United States)

This Science Update, from Science NetLinks, features an interview with Purdue University psychologist Susie Swithers about new research suggesting that artificial sweeteners may promote overeating. Science Updates are audio interviews with scientists and are accompanied by a set of questions as well as links to related Science NetLink lessons and other related resources.

Science Update

2004-08-02

251

Elemental analysis of topaz from northern areas of Pakistan and assessment of induced radioactivity level after neutron irradiation for color induction  

International Nuclear Information System (INIS)

To study the impurity elements, which render color-induced topaz long lived radionuclides, three samples of topaz, from three different cities of the Northern Pakistan (Baltistan, Gilgit and Mardan) were analyzed using k 0 instrumental neutron activation analysis (k0-INAA). The samples were irradiated in Pakistan Research Reactor-1 (PARR-1) and PARR-2 at Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad. The method was validated by analyzing IAEA-S7 reference material. In three samples a total of 22 trace level impurity elements were quantified. Among impurities, 10 elements including As, Ce, Ga, Ge, La, Na, Sb, Sc, U and Zn were common in topaz of all the three places. The storage time has been calculated for each sample required to bring the induced radioactivity down to permissible level given by US National Regulatory Commission. (author)

252

Resistance of mutants of sweet orange induced by gamma-rays to citrus canker (Xanthomonas citri subsp. citri) under artificial inoculation  

International Nuclear Information System (INIS)

The sweet oranges have great economic and social importance for Brazil. However, it is susceptible to citrus canker as the majority of citrus species. This disease is caused by Xanthomonas citri subsp. citri, bacteria that in case of high incidence can result in great economic damage. More resistant cultivars are the best long-term solution for management of citrus canker and one of the approaches can be the production of mutant plants. In a previous work, several induced mutant clones of sweet orange cv. Pera were selected. They showed lower intensity of symptoms of citrus canker in leaves and fruits in evaluations under natural incidence of the disease, in the field. The objective of this study is to assess the resistance to citrus canker of six mutant clones of cultivar Pera and control plants (three different varieties), in experiments of artificial inoculation. The parameters evaluated were: incubation period, diameter of the lesions and area under the disease progress curve (AUDPC), in evaluations every 15 days, until the 147th day. Only the clones 9-1, 9-2 and 9-3 showed lower incidence of disease, represented by the longest period of incubation of the disease, smaller diameter of lesion and lower AUDPC, in all experiment and using average data of the three experiments. This study is one of the first reports of success in citrus induced mutations aimed to obtaining greater resistance to diseases. (author)

253

Resistance of Mutants of Sweet Orange Induced by Gamma-rays to Citrus Canker (Xanthomonas citri subsp. citri) Under Artificial Inoculation  

International Nuclear Information System (INIS)

The sweet orange holds great economic and social importance for Brazil, but it is susceptible to citrus canker as is the majority of citrus species. In cases of high incidence, this disease caused by the bacterium Xanthomonas citri subsp. citri can result in great economic damage. More resistant cultivars are the best long-term solution for management of citrus canker and one of the approaches can be the production of mutant plants. In a previous work, several induced mutant clones of sweet orange cv. Pera were selected. They showed a lower intensity of symptoms of citrus canker in leaves and fruits in evaluations under natural incidence of the disease, in the field. The objective of this study is to assess the resistance to citrus canker of six mutant clones of cultivar Pera and control plants (three different varieties), in experiments of artificial inoculation. The parameters evaluated were: incubation period, diameter of the lesions and area under the disease progress curve (AUDPC), in evaluations every 15 days, until the 147th day. Only the clones 9-1, 9-2 and 9-3 showed lower incidence of disease, represented by the longest period of incubation of the disease, smaller diameter of lesion and lower AUDPC, using average data of the three experiments. This study is one of the first reports of success in citrus-induced mutations aimed to obtaining greater resistance to diseases. (author)

254

Probabilistic siting analysis of nuclear power plants emphasizing atmospheric dispersion of radioactive releases and radiation-induced health effects  

International Nuclear Information System (INIS)

A presentation is made of probabilistic evaluation schemes for nuclear power plant siting. Effects on health attributable to ionizing radiation are reviewed, for the purpose of assessment of the numbers of the most important health effect cases in light-water reactor accidents. The atmospheric dispersion of radioactive releases from nuclear power plants is discussed, and there is presented an environmental consequence assessment model in which the radioactive releases and atmospheric dispersion of the releases are treated by the application of probabilistic methods. In the model, the environmental effects arising from exposure to radiation are expressed as cumulative probability distributions and expectation values. The probabilistic environmental consequence assessment model has been applied to nuclear power plant site evaluation, including risk-benefit and cost-benefit analyses, and the comparison of various alternative sites. (author)

255

Measurement of the radioactivity induced in the soil around the decay volume of neutrino beam line at KEK  

International Nuclear Information System (INIS)

The Decay Volume of neutrino beam line of 12 GeV proton synchrotron at KEK was constructed underground on the KEK site. Then the soil around the Decay Volume were slightly activated. The radioactive concentrations of radionuclides were measured for the soil around the Decay Volume. Various long-lived radionuclides (Be-7, Na-22, Sc-46, Sc-47, V-48, Cr-51, Mn-52, Mn-54, Fe-59 and Co-60) were observed in soil samples by ?-ray spectra measurement, and H-3 was also detected by liquid scintillation counting. The maximum total radioactive concentration was 0.38 Bq/g, which was about 60% of the estimated value before the operation started. (author)

256

Artificial Neural Network Modeling of Healthy Risk Level Induced by Aircraft Pollutant Impacts around Soekarno Hatta International Airport  

Directory of Open Access Journals (Sweden)

Full Text Available Aircraft pollutant emissions are an important part of sources of pollution that directly or indirectly affect human health and ecosystems. This research suggests an Artificial Neural Network model to determine the healthy risk level around Soekarno Hatta International Airport-Cengkareng Indonesia. This ANN modeling is a flexible method, which enables to recognize highly complex non-linear correlations. The network was trained with real measurement data and updated with new measurements, enhancing its quality and making it the ideal method for this research. Measurements of aircraft pollutant emissions are carried out with the aim to be used as input data and to validate the developed model. The obtained results concerned the improved ANN architecture model based on pollutant emissions as input variables. ANN model processes variables—hidden layers—and gives an output variable corresponding to a healthy risk level. This model is characterized by a 4-10-1 scheme. Based on ANN criteria, the best validation performance is achieved at epoch 28 from 34 epochs with the Mean Squared Error (MSE of 9 × 10-3. The correlation between targets and outputs is confirmed. It validated a close relationship between targets and outputs. The network output errors value approaches zero. Further research is needed with the aim to enlarge the scheme of the ANN model by increasing its input variables. This is one of the major key defining environmental capacities of an airport that should be applied by Indonesian airport authorities. These would institute policies to manage or reduce pollutant emissions considering population and income growth to be socially positive.

Salah Khardi

2013-07-01

257

Predicting typhoon-induced storm surge tide with a two-dimensional hydrodynamic model and artificial neural network model  

Science.gov (United States)

Precise predictions of storm surges during typhoon events have the necessity for disaster prevention in coastal seas. This paper explores an artificial neural network (ANN) model, including the back propagation neural network (BPNN) and adaptive neuro-fuzzy inference system (ANFIS) algorithms used to correct poor calculations with a two-dimensional hydrodynamic model in predicting storm surge height during typhoon events. The two-dimensional model has a fine horizontal resolution and considers the interaction between storm surges and astronomical tides, which can be applied for describing the complicated physical properties of storm surges along the east coast of Taiwan. The model is driven by the tidal elevation at the open boundaries using a global ocean tidal model and is forced by the meteorological conditions using a cyclone model. The simulated results of the hydrodynamic model indicate that this model fails to predict storm surge height during the model calibration and verification phases as typhoons approached the east coast of Taiwan. The BPNN model can reproduce the astronomical tide level but fails to modify the prediction of the storm surge tide level. The ANFIS model satisfactorily predicts both the astronomical tide level and the storm surge height during the training and verification phases and exhibits the lowest values of mean absolute error and root-mean-square error compared to the simulated results at the different stations using the hydrodynamic model and the BPNN model. Comparison results showed that the ANFIS techniques could be successfully applied in predicting water levels along the east coastal of Taiwan during typhoon events.

Chen, W.-B.; Liu, W.-C.; Hsu, M.-H.

2012-12-01

258

Artificial Wetlands  

Science.gov (United States)

Golf courses are known as places of recreation. But some of them could someday double as water treatment facilities. Water hazards on golf courses can be used to control environmental hazards. That's according to Purdue University soil microbiologist Ron Turco. He says the artificial wetlands can also control flooding in surrounding communities, by collecting excess water. This Science Update looks at the research, which leads to these findings and offers links to other resources for further inquiry.

American Association for the Advancement of Science (; )

2005-04-11

259

Radioactive Material  

CERN Multimedia

The Radiation Protection Group of the Safety Commission is responsible for shipping of radioactive material from CERN to any external institute or organisation. The RP group is equally responsible for the reception of radioactive material shipped to any of the CERN sites. Anyone who needs to ship from or import into CERN radioactive material must contact the Radioactive Shipping Service of the RP group in advance. Instructions are available at: http://cern.ch/rp-shipping or in the Radiation Protection Procedure PRP13: https://edms.cern.ch/document/346823 Radiation Protection Group

2004-01-01

260

Radioactivity and food preservation  

International Nuclear Information System (INIS)

In food irradiation, electrons or electromagnetic radiation are used to destroy microorganisms and insects or to prevent seed germination. The economic advantages and health benefits of sterilizing food in this manner are clear, and numerous studies have confirmed that under strictly controlled conditions no undesirable changes or induced radioactivity are produced in the irradiated food

261

Fecundación Artificial  

Directory of Open Access Journals (Sweden)

Full Text Available Por Fecundación artificial se entiende, la fecundación de una hembra sin el servicio directo del macho, es decir la introducción al aparato genital femenino, del esperma que se ha recogido por medios artificiales. Esta fecundación, practicada en debidas condiciones, tiene el mismo efecto de la fecundación natural, con las ventajas que veremos más adelante. La fecundación artificial permite explotar un reproductor a su máximum de capacidad, ya que se considera, para no hacer cálculos alegres, que un servicio de un caballo puede servir, diluido, por lo menos para cuatro yeguas, según los autores americanos, y para 10 a 15, según otros autores. El toro y el carnero pueden dar esperma suficiente en un servicio para fecundar de 10 a 12 hembras, según,los americanos, y según otros autores, hasta para 40. Los investigadores rusos han podido fecundar hasta 60 vacas con un solo servicio y han logrado con reproductores valiosos, fecundar 10.263 vacas por toro, a pesar de que éstos sólo han servido, durante un periodo de monta de sólo dos meses. Estos mismos han logrado fecundar artificialmente 2.733 ovejas con un solo carnero, y 1.403 con otro Los investigadores americanos han contado 22 servicios a un carnero vigoroso en un periodo de ocho horas, y durante este tiempo produjo esperma suficiente para haber fecundado 200 ovejas artificialmente. La fecundación artificial sirve para evitar la trasmisión de enfermedades que se contagian por el coito, tales como la durina, enfermedad ésta producida por un tripanosoma que por fortuna no existe entre nosotros. A las estaciones de monta llevan con frecuencia hembras afectadas de enfermedades como la vaginitis granulosa de la vaca, que se contagia al toro y de éste a otras hembras. Como el control sanitario de toda hembra llevada al servicio de un reproductor de estas estaciones de monta no siempre puede efectuarse por dificultades de distinta índole, mediante la fecundación artificial se evita el contagio de los reproductores y la consiguiente propagación. Mediante la fecundación artificial se puede efectuar el servicio a distancia, sin el costo y riesgo del transporte del macho o de la hembra.

Ochoa. Fidel

1939-10-01

262

Experimental demonstration of differing impacts of pulsed and continuous operation of a deuterium-tritium neutron source on induced radioactivity in the context of ITER  

International Nuclear Information System (INIS)

The work reported herein was conducted in response to an ITER Task to demonstrate experimentally that pulsed and continous operations of a D-T neutron source lead, in general, to differing impacts on inventory of induced radioactivity, on one hand, and to verify calculational methods, on the other. In a series of experiments conducted for the purpose, half lives of observed radioisotopes varied from 1 minute (25Na) to 271 days (57Co). Relatively short pulse lengths, 1 minute to 3 minute duration, were chosen. A pneumatic transport system was employed to transport foils of niobium, iron, aluminum, vanadium, nickel, and magnesium for irradiation close to the D-T neutron source. Three duty factors and two kinds of power levels were used for various neutron pulse trains. The experimental data was processed to obtain ratio of inventories in pulsed to continuous operation scenarios for each of the observed radioisotope. We observe a large reduction in radioactive inventories for values of t1/2/p (half life/pulse duration) lying in the range of 1 to 10. Interestingly, random power pulse trains show even larger reduction in radioactive inventory: the ratio of inventories drops to approx.0.14 for t1/2/p = 3.15 (27Mg) for a duty factor of 20% and a train of 10 pulses, whereas it would have hit a minimum of 0.33 for t1/2/p = 3.53 for constant power level. 14 refs., 10 figs., 1 tab., 1 tab

263

Purification of highly-radioactive mouse interferon produced by Ehrlich ascites tumour cells induced by Sendai virus  

International Nuclear Information System (INIS)

Mouse interferon (IFN) was produced to high titres after induction of Ehrlich ascites tumour cells with Sendai virus by using an improved procedure. The IFN molecules were labelled during their synthesis by the incorporation of [3H]leucine and [3H]lysine. Electrophoretically homogeneous labelled IFN with a molecular weight of 34000 was obtained after a two-step purification procedure using poly(I)-agarose and octyl-Sepharose column chromatography followed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The specific radioactivity of this IFN was about 10 ct/min/IFN unit. (author)

264

Fast identification of biominerals by means of stand-off laser-induced breakdown spectroscopy using linear discriminant analysis and artificial neural networks  

Energy Technology Data Exchange (ETDEWEB)

The goal of this paper is to compare two selected statistical techniques used for identification of archeological materials merely on the base of their spectra obtained by stand-off laser-induced breakdown spectroscopy (stand-off LIBS). Data processing using linear discriminant analysis (LDA) and artificial neural networks (ANN) were applied on spectra of 18 different samples, some of them archeological and some recent, containing 7 types of material (i.e. shells, mortar, bricks, soil pellets, ceramic, teeth and bones). As the input data PCA scores were taken. The intended aim of this work is to create a database for simple and fast identification of archeological or paleontological materials in situ. This approach can speed up and simplify the sampling process during archeological excavations that nowadays tend to be quite damaging and time-consuming. - Highlights: Black-Right-Pointing-Pointer We use statistical techniques for identification of archeological materials. Black-Right-Pointing-Pointer Input data for LDA and ANN are PC scores counted from stand-off LIBS spectra. Black-Right-Pointing-Pointer The method used for identification of archeological materials provides good results. Black-Right-Pointing-Pointer After recording more spectra we can get useful tool for rapid analysis in situ.

Vitkova, Gabriela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Novotny, Karel, E-mail: codl@sci.muni.cz [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Prokes, Lubomir [Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno (Czech Republic); Hrdlicka, Ales [Central European Institute of Technology, CEITEC MU, Masaryk University (Czech Republic); Kaiser, Jozef [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); X-ray micro CT and nano CT research group, CEITEC-Central European Institute of Technology, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); Novotny, Jan [X-ray micro CT and nano CT research group, CEITEC-Central European Institute of Technology, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic); Malina, Radomir; Prochazka, David [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 616 69 Brno (Czech Republic)

2012-07-15

265

Fast identification of biominerals by means of stand-off laser?induced breakdown spectroscopy using linear discriminant analysis and artificial neural networks  

International Nuclear Information System (INIS)

The goal of this paper is to compare two selected statistical techniques used for identification of archeological materials merely on the base of their spectra obtained by stand-off laser-induced breakdown spectroscopy (stand-off LIBS). Data processing using linear discriminant analysis (LDA) and artificial neural networks (ANN) were applied on spectra of 18 different samples, some of them archeological and some recent, containing 7 types of material (i.e. shells, mortar, bricks, soil pellets, ceramic, teeth and bones). As the input data PCA scores were taken. The intended aim of this work is to create a database for simple and fast identification of archeological or paleontological materials in situ. This approach can speed up and simplify the sampling process during archeological excavations that nowadays tend to be quite damaging and time-consuming. - Highlights: ? We use statistical techniques for identification of archeological materials. ? Input data for LDA and ANN are PC scores counted from stand-off LIBS spectra. ? The method used for identification of archeological materials provides good results. ? After recording more spectra we can get useful tool for rapid analysis in situ.

266

An inducible artificial microRNA system for Chlamydomonas reinhardtii confirms a key role for heat shock factor 1 in regulating thermotolerance.  

Science.gov (United States)

Several RNA silencing strategies employing antisense or inverted repeat constructs have been applied to Chlamydomonas reinhardtii. Problems inherent to these strategies, like off-target effects by unpredictable generation of siRNAs, were solved previously by constructs allowing for routine expression of specific artificial microRNAs (amiRNAs). Yet missing was a routine tool for inducible amiRNA expression, which to establish was the aim of this work. For this, we equipped a recently developed amiRNA expression vector with the NIT1 promoter, which is repressed by ammonium and activated by nitrate. We tested this conditional amiRNA vector with heat shock factor 1 (HSF1) as target. HSF1 transcripts in transformants were already reduced ~2 h after transfer from ammonium to nitrate-containing medium. In contrast, HSF1 protein levels declined only ~8 h after the shift and were strongly reduced after 24 h, suggesting that HSF1 is a stable protein and diluted out by growth. HSF1 levels recovered partly when transformant cells were shifted back to ammonium for 72 h. Transformants developed thermosensitivity only on nitrate and thermosensitivity correlated with strong reduction in HSF1 levels, hence supporting our earlier conclusion that HSF1 is a key regulator for thermotolerance in Chlamydomonas. PMID:20449593

Schmollinger, Stefan; Strenkert, Daniela; Schroda, Michael

2010-08-01

267

On Radioactivity–Exposed Nanophotodetector Optoreliability  

OpenAIRE

The optoelectronic reliability of representative radioactivity-exposed nanophotodetectors and the degree of functionally tolerable radioactivity-induced responsivity de-emphasis, against increasing cumulative radioactivity-dose, is notionally considered and modelled, with a view towards experimental findings concerning p-i-n photosensors being exposed to regulated successive (?, ?)-particle bombardments.

Anagnostakis, Emmanuel A.

2011-01-01

268

Specific Radioactivity of Neutron Induced Radioisotopes: Assessment Methods and Application for Medically Useful 177Lu Production as a Case  

Directory of Open Access Journals (Sweden)

Full Text Available The conventional reaction yield evaluation for radioisotope production is not sufficient to set up the optimal conditions for producing radionuclide products of the desired radiochemical quality. Alternatively, the specific radioactivity (SA assessment, dealing with the relationship between the affecting factors and the inherent properties of the target and impurities, offers a way to optimally perform the irradiation for production of the best quality radioisotopes for various applications, especially for targeting radiopharmaceutical preparation. Neutron-capture characteristics, target impurity, side nuclear reactions, target burn-up and post-irradiation processing/cooling time are the main parameters affecting the SA of the radioisotope product. These parameters have been incorporated into the format of mathematical equations for the reaction yield and SA assessment. As a method demonstration, the SA assessment of 177Lu produced based on two different reactions, 176Lu (n,?177Lu and 176Yb (n,? 177Yb (?- decay 177Lu, were performed. The irradiation time required for achieving a maximum yield and maximum SA value was evaluated for production based on the 176Lu (n,?177Lu reaction. The effect of several factors (such as elemental Lu and isotopic impurities on the 177Lu SA degradation was evaluated for production based on the 176Yb (n,? 177Yb (?- decay 177Lu reaction. The method of SA assessment of a mixture of several radioactive sources was developed for the radioisotope produced in a reactor from different targets.

Van So Le

2011-01-01

269

Ambient radioactivity levels and radiation doses. Annual report 2010  

International Nuclear Information System (INIS)

The annual report 2010 on ambient radioactivity levels and radiation doses covers the following topics in two parts: Part (A) General information: (I) Natural environmental radioactivity. (II) Artificial radioactivity in the environment. (III) Occupational radiation exposure. (IV) Radiation exposures from medical applications. (V) The handling of radioactive materials and sources of ionizing radiation. (VI) Non-ionizing radiation. Part (B) Current data and their evaluation: (I) Natural environmental radioactivity. (II) Artificial radioactivity in the environment. (III) Occupational radiation exposure. (IV) Radiation exposures from medical applications. (V) The handling of radioactive materials and sources of ionizing radiation. (VI) Non-ionizing radiation (electromagnetic fields, optical radiation). The Annex covers explanation on terms, physical units, glossary, list of abbreviations, radiation protection laws, regulations etc. and a list of selected radionuclides.

270

Ambient radioactivity levels and radiation doses. Annual report 2011  

International Nuclear Information System (INIS)

The annual report 2011 on ambient radioactivity levels and radiation doses covers the following issues: Part A: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. Part B; Current data and their evaluation: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. The Appendix includes Explanations of terms, radiation doses and related units, external and internal radiation exposure, stochastic and deterministic radiation effects, genetic radiation effects, induction of malignant neoplasm, risk assessment, physical units and glossary, laws, ordinances, guidelines, recommendations and other regulations concerning radiation protection, list of selected radionuclides.

271

Reliability assessment of high energy particle induced radioactivity calculation code DCHAIN-SP 2001 by analysis of integral activation experiments with 14 MeV neutrons  

Energy Technology Data Exchange (ETDEWEB)

Reliability assessment for the high energy particle induced radioactivity calculation code DCHAIN-SP 2001 was carried out through analysis of integral activation experiments with 14-MeV neutrons aiming at validating the cross section and decay data revised from previous version. The following three kinds of experiments conducted at the D-T neutron source facility, FNS, in JAERI were employed: (1) the decay gamma-ray measurement experiment for fusion reactor materials, (2) the decay heat measurement experiment for 32 fusion reactor materials, and (3) the integral activation experiment on mercury. It was found that the calculations with DCHAIN-SP 2001 predicted the experimental data for (1) - (3) within several tens of percent. It was concluded that the cross section data below 20 MeV and the associated decay data as well as the calculation algorithm for solving the Beteman equation that was the master equation of DCHAIN-SP were adequate. (author)

Kai, Tetsuya; Maekawa, Fujio; Kasugai, Yoshimi; Takada, Hiroshi; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kosako, Kazuaki [Sumitomo Atomic Energy Industries, Ltd., Tokyo (Japan)

2002-03-01

272

Environmental radioactivity and radiation exposure  

International Nuclear Information System (INIS)

In 1977 population exposure in the Federal Republic of Germany has not changed as compared to the previous years. The main share of the total exposure, nearly two thirds, is attributed to natural radioactive substances and cosmic radiation. The largest part (around 85%) of the artificial radiation exposure is caused by X-ray diagnostics. In comparison to this, radiation exposure from application of ionizing radiation in medical therapy, use of radioactive material in research and technology, or from nuclear facilities is small. As in the years before, population exposure caused by nuclear power plants and other nuclear facilities is distinctly less than 1% of the natural radiation exposure. This is also true for the average radiation exposure within a radius of 3 km around nuclear facilities. On the whole, the report makes clear that the total amount of artificial population exposure will substantially decrease only if one succeeds in reducing the high contribution to the radiation exposure caused by medical measures. (orig.)

273

Effect of photoperiod on endocrine profiles and vitellogenin expression in European eels Anguilla anguilla during artificially induced ovarian development.  

Science.gov (United States)

The aim of this work was to determine the effects of dark and light conditions on the E2, testosterone and thyroid hormones levels and on the gene expression levels (vitellogenin 1, vitellogenin 2, and estradiol receptor one) in European eels (Anguilla anguilla) during ovarian development induced by increasing doses of carp pituitary extracts (CPEs). The subjects were divided into 2 groups: 14-hour light:10-hour dark (Light Group) and 24-hour darkness (Dark Group). All the eels received intramuscular injections with CPE at a dosage of 10 mg/kg body weight (BW) once a week for the first 3 weeks, 20 mg/kg BW fourth-sixth week, 30 mg/kg BW seventh-ninth week, and 40 mg/kg up to the end of the experiment (13th week). Vitellogenin and estradiol receptor expression levels did not show significant differences between the two housing conditions whereas in both groups vitellogenin mRNA increased starting from first CPE injection. Testosterone and 17-beta estradiol plasma levels were significantly greater in the Dark Group compared with the Light Group starting from the ninth and the 13th week, respectively. These results suggest that darkness could be a useful variable for standardizing gonadal maturation in eels kept in captivity. PMID:25459031

Parmeggiani, A; Govoni, N; Zannoni, A; Di Biase, A; Sirri, R; Forni, M; Mandelli, M; Mordenti, O

2015-03-01

274

High-energy proton irradiation and induced radioactivity analysis for some construction materials for the CERN LHC  

International Nuclear Information System (INIS)

The dose rate to personnel due to remnant radioactivity during maintenance periods will be an important issue at the forthcoming Large Hadron Collider (LHC). Among the most abundant construction materials are aluminum, steel, copper and lead. In order to obtain more reliable estimates on the radioisotope production in a high-energy hadron environment, small samples of these materials behind the beam-stop of the CERN 24 GeV/c proton synchrotron were irradiated. This environment is characterized by high spallation neutron flux and a non-negligible contribution of protons and pions up to the total beam momentum. Gamma-ray spectra of the samples were measured and analyzed with the SAMPO program and detailed nuclide identification was carried out with the SHAMAN program. The total energy emission and results of the spectrum analyses were compared to predictions of the FLUKA hadron cascade simulation package. (author)

275

Radioactivity: A stocktaking of misconceptions and misunderstandings  

International Nuclear Information System (INIS)

Ignorance about the nature of radioactivity contributed to confusions and misunderstandings of the processes involved in the Chernobyl reactor accident. People do not discriminate between natural and artificial radioactivity and explain the actual hazard, health hazards, enhanced susceptibility to cancer and leukaemia and contamination of food by merely quoting measured values, half lives and small doses which does not help the confusion or misconceptions. The author discusses some principal ways how to remedy this situation. (DG)

276

Total Artificial Heart  

Science.gov (United States)

... NHLBI on Twitter. What Is a Total Artificial Heart? A total artificial heart (TAH) is a device ... the chest to an outside power source. Normal Heart and CardioWest Total Artificial Heart Figure A shows ...

277

The environmental assessment of radioactive materials using yeast DNA microarray. Genomic profiling of thorium-induced changes in yeast cells  

International Nuclear Information System (INIS)

We evaluated the toxicity of thorium (nitrate) in the environment by using a Saccharomyces cerevisiae DNA microarray, and present the genome-wide profile of induced yeast genes. A total of 185 out of about 6,000 genes spotted on the microarray chip were induced by thorium. Functional analysis of these genes revealed that gene categories in 'C-compound and carbohydrate metabolism', 'Energy', 'Lipid fatty acid and isoprenoid metabolism' and 'Cell rescue, defense and virulence' were the most highly induced by thorium treatment. Moreover, localization analysis of these genes revealed that gene categories in 'Extracellular', 'Cell wall', 'Plasma membrane' and 'Cell periphery' were also highly induced by thorium treatment. In the categories of 'Cell rescue, defense and virulence', genes related to oxidative stress were induced. In the categories of 'C-compound and carbohydrate metabolism' and 'Energy', genes relate to glycogen metabolism were observed. In the categories of 'Extracellular' and 'Cell wall', genes related to cell component were detected while genes related to sugar transporters were detected in the categories of Plasma membrane'. These results provide the first insight into the effect of thorium on yeast cells. (author)

278

Concentrating Radioactivity  

Science.gov (United States)

By concentrating radioactivity contained on luminous dials, a teacher can make a high reading source for classroom experiments on radiation. The preparation of the source and its uses are described. (DT)

Herrmann, Richard A.

1974-01-01

279

Simulated Radioactivity  

Science.gov (United States)

Describes the errors in the sugar-cube experiment related to radioactivity as described in Project Physics course. The discussion considers some of the steps overlooked in the experiment and generalizes the theory beyond the sugar-cube stage. (PS)

Boettler, James L.

1972-01-01

280

Radioactivity Calculations  

Science.gov (United States)

Three problems in radioactive buildup and decay are presented and solved. Matrix algebra is used to solve the second problem. The third problem deals with flux depression and is solved by the use of differential equations. (LC)

Onega, Ronald J.

1969-01-01

281

Radioactive Iodine  

Science.gov (United States)

... determine the activity of the intact thyroid gland (Thyroid scan and Radioactive Iodine uptake, RAIu), since it is ... no special radiation precautions are necessary after a thyroid scan or RAIu with I-123. When is rai ...

282

Artificial organs and transplantation  

Energy Technology Data Exchange (ETDEWEB)

The status of development of artificial organs in 1977 is reviewed. A small, wearable battery-powered artificial kidney weighing about 8 lb and using a hollow fiber dialyzer is described that has been proved effective for home dialysis of patients. Results of tests of the performance of artificial hearts in calves, improvements in the development of artificial arms, and preliminary results in development of artificial eyes and artificial ears are reported. (CH)

Kolff, W.J.

1977-03-01

283

Changes in the expression of interleukin-1beta and lipopolysaccharide-induced TNF factor in the oviduct of laying hens in response to artificial insemination.  

Science.gov (United States)

The aim of this study was to determine the physiological significance of interleukin-1beta (IL1B) and lipopolysaccharide-induced TNF factor (LITAF) in the fate of sperm in the oviduct of laying hens after artificial insemination (AI). Laying hens were inseminated with fresh semen, PBS or seminal plasma and tissues from different oviductal segments were collected to observe the general histology, changes in the mRNA expression of IL1B and LITAF and the localization of positive cells expressing immunoreactive IL1B (irIL1B). Semi-quantitative RT-PCR was used to observe the changes in mRNA expression of these molecules in the infundibulum, uterus, utero-vaginal junction (UVJ), and vagina after insemination. Intact sperm in the lumen and between the primary or secondary folds of the vagina were found until 6 h after insemination but were degraded at 12 h. The mRNA expression of IL1B and LITAF was significantly increased in the vagina until 6 h after AI but remained unchanged in the other oviductal segments. In the tissue of the vagina and UVJ, irIL1B was localized in the mucosal stroma. The number of irIL1B-positive cells was increased in the vagina but almost unchanged in UVJ after insemination with semen. Significant changes were not observed in the mRNA expression and irIL1B-positive cells in the vagina after PBS or seminal plasma insemination. The increase of IL1B and LITAF in the vagina may lead to sperm degradation and elimination by cilia of surface epithelium, whereas their lower levels in UVJ may permit sperm to survive in sperm storage tubules. PMID:18539728

Das, Shubash Chandra; Isobe, Naoki; Yoshimura, Yukinori

2009-03-01

284

Radioactive pollution  

International Nuclear Information System (INIS)

The basic data available to-day on radioactive pollution levels of various origins are compared to those of natural origin. In the year 2000, radioactive pollution from nuclear electricity will represent only one additional day of, natural irradiation per year. Human data now available on action of chronic irradiation are given, together with the results of very many experiments on animals. Finally, the risk evaluation which can be derived are analyzed, as well as the safety limits they imply

285

The radioactivity of the sea  

International Nuclear Information System (INIS)

The radioactivity in the world's surface sea water averages 13.6 Bq/kg of water. Over 88% of this activity arises from a single natural radionuclide, 40K, and 7% of the remainder results from nuclear weapon test fallout. Variations in the radioactivity occur due to changes in salinity, weapon test fallout and discharges of artificial radionuclides, and are examined here on the basis of published measurements. The most radioactive sea identified by these measurements is the Dead Sea, which averages 178 Bq/kg due to its high salinity. Other enclosed, highly saline waters can be expected to have similar levels. The radioactivity in open seas varies within a much narrower range, generally within 20% of the world average. The highest averages are found in the Persian Gulf (22 Bq/kg), the Red Sea (15 Bq/kg) and the Eastern Mediterranean (14.6 Bq/kg). The Irish Sea averaged 13.7 Bq/kg in 1987, with the effect of the Sellafield discharges being partly offset by lower than average salinity. Although higher levels occurred in the Irish Sea during the 1970s when the Sellafield discharges were higher, the average level has always been much less than that in the Dead Sea, so that the Irish Sea has never been the most radioactive sea in the world. Exceptionally low levels of radioactivity (4 Bq/kg) occur in the Baltic Sea due to dilution by fresh water. (author)

286

Artificial sources of radiation exposure  

International Nuclear Information System (INIS)

Artificial sources of ionizing radiation, affecting population, are considered. The sources are subdivided into two main groups: environmental contaminants and non-contaminants. With regard to the first group enterprises of nuclear power engineering and their fuel cycle (uranium mining, fuel element production, NPPs, emergency effluents from reactors, regeneration of irradiated fuel, radioactive material transport) nuclear weapon tests and industrial nuclear explosions are considered. In the second group ionizing radiation sources used in medicine, as well as corresponding consumer goods (TV sets, radioluminescence devices, etc.) are considered

287

Environmental radioactivity annual report 1986  

International Nuclear Information System (INIS)

The New Zealand environmental radioactivity programme was modified during 1986, with a reduction in the number of monitoring stations and an increase in the sensitivity to airborne radioactivity of the remaining stations. During 1986 artificial environmental radioactivity in the New Zealand and South Pacific areas continued to be at the very low level typical of recent years. The total beta activity in air averaged 0.07 mBq m-3. The average strontium-90 deposition for the year was 0.2 MBq km-2. Strontium-90 in dairy milk ranged from 0.014 to 0.062 Bq gCa-1 and caesium-137 ranged from -1. Emissions from the damaged Chernobyl nuclear reactor were not detected in the region. (author). 8 refs., 6 tabs

288

Gamma-H2AX as a biomarker of DNA damage induced by ionizing radiation in targeted and bystander human artificial skin models and peripheral blood lymphocytes  

Science.gov (United States)

Ionizing radiation (IR) exposure is inevitable. In addition to exposure from cosmic rays, the sun and radioactive substances, modern society has created new sources of radiation exposure such as space and high altitude journeys, X-ray diagnostics, radiological treatments and the increasing threat of radiobiological terrorism. For these reasons, a reliable, reproducible and sensitive assessment of dose and time exposure to IR is essential. We developed a minimally invasive diagnostic test for IR exposure based on detection of a phosphorylated variant of histone H2AX (gamma-H2AX), which occurs specifically at sites of DNA double-strand breaks (DSBs). The phosphorylation of thousands of H2AX molecules forms a gamma-H2AX focus in the chromatin flanking the DSB site that can be detected in situ. We analyzed gamma- H2AX focus formation in both directly irradiated cells as well as in un-irradiated "bystanders" in close contact with irradiated cells. In order to insure minimal invasiveness, we examined commercially available artificial skin models as a surrogate for human skin biopsies as well as peripheral blood lymphocytes. In human skin models, cells in a thin plane were microbeamirradiated and gamma-H2AX formation was measured both in irradiated and in distal bystander cells over time. In irradiated cells DSB formation reached a maximum at 15-30 minutes post- IR and then declined within several hours; all cells were affected. In marked contrast, the incidence of DSBs in bystander cells reached a maximum by 12-48 hours post-irradiation, gradually decreasing over the 7 day time course. At the maxima, 40-60% of bystander cells were affected. Similarly, we analyzed blood samples exposed to IR ex vivo at doses ranging from 0.02 to 3 Gy. The amount of DNA damage was linear in respect to radiation dose and independent of the age or sex of the blood donor. The method is highly reproducible and highly sensitive. In directly irradiated cells, the number of gamma-H2AX foci peaked 30 min after irradiation and then declined at a relatively steady pace as the cell repaired the DNA damage. Radiation effects were still detectable after 48 hrs for doses greater than 1 Gy and remained linear to initial dose. Activated bystander lymphocytes cultured with media from irradiated lymphocytes exhibited a two-fold increased damage response as seen by gamma- H2AX formation. The effect reached a maximum 3 hrs post-exposure and was retained for over 24 hrs. Thus, detection of gamma-H2AX formation to determine DNA damage in a minimally invasive skin test and a non-invasive blood test could be useful and promising tools to analyze direct and indirect effects of radiation exposure.

Redon, Christophe; Dickey, Jennifer; Bonner, William; Sedelnikova, Olga

289

Teaching concepts in the field of radioactivity and nuclear energy  

International Nuclear Information System (INIS)

This issue of 'Naturwissenschaften im Unterricht', dealing with the subjects of physics and chemistry, gives an account of the fundamentals of radioactivity, nuclear fission, controlled nuclear fission, nuclear power plants, dosimetry, safety engineering, shielding measures to prevent the release of radioactive substances, pressure engineering, emergency core cooling systems, waste disposal and natural and artificial environmental radioactivity. Teachers will find helpful hints as to the method of instruction and the explanation of problems. (DG)

290

Nanobiocatalytic assemblies for artificial photosynthesis.  

Science.gov (United States)

Natural photosynthesis, a solar-to-chemical energy conversion process, occurs through a series of photo-induced electron transfer reactions in nanoscale architectures that contain light-harvesting complexes, protein-metal clusters, and many redox biocatalysts. Artificial photosynthesis in nanobiocatalytic assemblies aims to reconstruct man-made photosensitizers, electron mediators, electron donors, and redox enzymes for solar synthesis of valuable chemicals through visible light-driven cofactor regeneration. The key requirement in the design of biocatalyzed artificial photosynthetic process is an efficient and forward electron transfer between each photosynthetic component. This review describes basic principles in combining redox biocatalysis with photocatalysis, and highlights recent research outcomes in the development of nanobiocatalytic assemblies that can mimic natural photosystems I and II, respectively. Current issues in biocatalyzed artificial photosynthesis and future perspectives will be briefly discussed. PMID:24832068

Kim, Jae Hong; Nam, Dong Heon; Park, Chan Beum

2014-08-01

291

History of radioactivity  

International Nuclear Information System (INIS)

The author describes the historical development of the physics of atoms and nuclei. After a consideration of the ancient Greek philosophy concerning atoms the behaviour of gases is discussed with regards to statistical mechanics. Then the developement of chemistry from alchemy is described. Thereafter the early studies of gas discharges are described with regards to the electronic structure of atoms. In this connection the periodic system of elements is considered. Then the detection of the ?-radiation of Uranium by Becquerel and the detections of M. and P. Curie are described. Thereafter the radiactive decay of nuclei is discussed. Then a popular introduction into nuclear structure is given with special regards to artificial radioactivity and nuclear fission. Finally nuclear reactors, the atomic bombs, applications of radionuclides, and problems of radiation protection are described. (HSI)

292

Única ou dupla inseminação artificial em tempo fixo em porcas com ovulações induzidas pelo Hormônio Luteinizante / Single or double artificial insemination in fixed time in sows with ovulation induced by Luteinizing Hormon  

Scientific Electronic Library Online (English)

Full Text Available Duzentas e cinqüenta e quatro matrizes Camborough 22 (PIC®), foram divididas em 3 tratamentos: T 1 (n=60) - 600 UI de eCG após desmama e 5 mg de LH, 72 h após eCG , com única inseminação artificial (IA) (24 h após LH); T 2 (n=95) - mesmo tratamento hormonal do T1, com 2 IA (24 e 32 h após LH); T 3 ( [...] n=99) - grupo controle sem tratamento hormonal, com 3 IA. As médias de intervalo desmame-estro (IDE) em T1, T2 e T3 foram de 87,4 ± 3,0 (87 a 111), 87 ± 0 (87) e 99,9 ± 13,6 (63 a 135) horas, respectivamente, sendo reduzidas (P horas, respectivamente para T1, T2 e T3, sendo menor (P Abstract in english Two hundred fifty four sows Camborough 22 (PIC®), were divided in 3 treatments: T 1 (n=60) - 600 UI of eCG after weaning and 5 mg of LH, after 72 h, with single artificial insemination (AI) (24 h after LH); T 2 (n=95) - same hormonal treatment of T1, with 2 AI (24 and 32 h after LH); T 3 (n=99) - co [...] ntrol group, with 3 AI. The averages of weaning-to-estrus interval (WEI) in T1, T2 and T3 were of 87,4 ± 3,0 (87 - 111), 87 ± 0 (87) and 99,9 ± 13,6 (63 - 135) h, respectively, been reduced (P

293

Radioactivity measurement  

International Nuclear Information System (INIS)

A problem with ore sorting arrangements is that radiation is difficult to measure accurately while particles are moving at speed past the detector. This is particulary so when dealing with ores such as gold ores which have weak emissions. A method of measuring radioactive emissions from moving radioactive material includes the steps of shielding the radiation detector(s) so that the angle of acceptance of the receptor surface is restricted, and further shielding the shielded portion of the detector with a second material which is less radiation emissive than the material of the first shield. This second shield is between the first shield and the detector

294

Radioecological observations in the trace-measurement and dosimetric evaluation of radioactive traces in the air  

International Nuclear Information System (INIS)

The following topics are dealt with: Weekly measurement of 137Cs and 40K, long-time measurement series, natural radioactive nuclides, artificial radioactive nuclides, 85Kr, 133Xe, 90Sr, 137Cs, and 238-240Pu, the radioecology of 129I, dosimetric evaluation of radioactive traces in air. (HSI)

295

Wear measurement using radioactive tracer technique based on proton, deuteron and {alpha}-particle induced nuclear reactions on molybdenum  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Proton, deuteron, {sup 3}He and {alpha}-particle activation of Mo. Black-Right-Pointing-Pointer TLA (thin layer activation). Black-Right-Pointing-Pointer Wear measurement. Black-Right-Pointing-Pointer Integral production yields. Black-Right-Pointing-Pointer Wear curves (specific activity versus penetration depth). - Abstract: Excitation functions of light ion induced nuclear reactions on natural molybdenum have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for various applications. Excitation functions of {sup 93,94g,94m,95g,95m,96,99m}Tc, {sup 90,93m,99}Mo, {sup 90,91m,92m,95m,95g,96}Nb and {sup 88,89}Zr were measured up to 50 MeV deuteron energy Tarkanyi et al., 2012 [1], {sup 93m,93g,94m,94g,95m,95g,96g,99m}Tc, {sup 90,93m,99}Mo, {sup 90,92m,95m,95g,96}Nb and {sup 88,89}Zr were measured up to 40 MeV proton energy Tarkanyi et al., 2012 [2] and {sup 93m,93g,94m,94g,95m,95g,96g,99m}Tc, {sup 93m,99}Mo, {sup 90}Nb, {sup 94,95,97,103}Ru and {sup 88}Zr were measured up to 40 MeV alpha energy Ditroi et al., 2012 [3] by using the stacked foil technique and activation method. The results for {sup 3}He induced reactions on natural Mo were taken from the literature Comparetto and Qaim, 1980 [4]. According to their half-lives, from the above listed radionuclides the {sup 95m,96}Tc, {sup 91m,92m,95m,95g}Nb, {sup 99}Mo, {sup 103,97}Ru and {sup 88}Zr are suitable candidates for wear measurement by using thin layer activation (TLA) method. The goal of this work was to determine the necessary nuclear data for TLA of the above radionuclides and to prove their applicability for wear measurements.

Ditroi, F., E-mail: ditroi@atomki.hu [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary); Tarkanyi, F.; Takacs, S. [Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary)

2012-11-01

296

Radioactivity Monitoring of the Irish Environment 2006  

International Nuclear Information System (INIS)

This report presents the results of the environmental radioactivity monitoring programme carried out by the Radiological Protection Institute of Ireland (RPII) in 2006. This programme aims to assess the exposure of the Irish population to artificial radioactivity in the environment, to review the temporal and geographical distribution of contaminating radionuclides and to maintain systems and procedures which would allow a rapid assessment of environmental contamination to be made in the event of a radiological emergency. Radioactivity is present in the environment due to natural processes, the testing of nuclear weapons in the atmosphere, past nuclear accidents such as that at Chernobyl in Ukraine and the routine discharge of radionuclides from nuclear installations. Liquid discharges from the British Nuclear Group reprocessing plant at Sellafield in Cumbria in the north-west of England, which are licensed by the UK Environment Agency, continue to be the dominant source of artificial radioactivity in the Irish marine environment. The key elements of the monitoring programme implemented by the RPII in 2006 included; assessment of ambient radioactivity based on measurements of radioactivity in air and of external gamma dose rate at permanent monitoring stations located throughout the country; assessment of levels of radioactivity in drinking water; assessment of levels of radioactivity in foodstuffs based on measurements of total diet, milk and various ingredients; assessment of levels of radioactivity in the Irish marine environment based on sampling and measurement of seawater, sediment, seaweed, fish and shellfish. The RPII monitored airborne radioactivity at ten stations located throughout the country. One of these stations is equipped with a high volume sampler, which allows concentrations of caesium-137 to be measured; another is equipped to detect the presence of the gas krypton-85. This gas is released into the environment primarily as a result of the reprocessing of nuclear fuel. During 2006, levels of radionuclides in airborne radioactivity were low and consistent with measurements in previous years. External gamma dose rates were monitored continuously at fifteen stations. No abnormal levels were observed. In accordance with the RPII's drinking water monitoring protocol, a number of water supplies from Cork, Dublin, Galway and Limerick were tested and found to be within the requirements for radioactivity set out in the relevant national standards. The RPII sampled and measured levels of radioactivity in mixed diet, milk and various other foodstuffs including milk products, baby foods, beef, lamb, poultry and vegetables. These measurements show that levels of artificial radioactivity in the Irish diet continue to be low. In the region of 170 samples of fish, shellfish, seaweed, seawater and sediment were analysed for a range of radionuclides. Along the Irish coastline the highest radioactivity concentrations observed were in the north-east. The main pathway contributing to the exposure of the Irish public to artificial radioactivity from the marine environment is the consumption of seafood. Caesium-137 continues to be the dominant radionuclide, accounting for approximately 70% of the total dose. The dose to the Irish population due to caesium-137 has declined significantly over the last two decades corresponding to the reduction in discharges of this radionuclide from Sellafield. The annual doses incurred by the Irish public as a result of artificial radioactivity in the environment do not constitute a significant health risk and are small compared with the dose received as a result of natural radiation

297

Application of a series of artificial neural networks to on-site quantitative analysis of lead into real soil samples by laser induced breakdown spectroscopy  

Science.gov (United States)

Artificial neural networks were applied to process data from on-site LIBS analysis of soil samples. A first artificial neural network allowed retrieving the relative amounts of silicate, calcareous and ores matrices into soils. As a consequence, each soil sample was correctly located inside the ternary diagram characterized by these three matrices, as verified by ICP-AES. Then a series of artificial neural networks were applied to quantify lead into soil samples. More precisely, two models were designed for classification purpose according to both the type of matrix and the range of lead concentrations. Then, three quantitative models were locally applied to three data subsets. This complete approach allowed reaching a relative error of prediction close to 20%, considered as satisfying in the case of on-site analysis.

El Haddad, J.; Bruyère, D.; Ismaël, A.; Gallou, G.; Laperche, V.; Michel, K.; Canioni, L.; Bousquet, B.

2014-07-01

298

Capillary electrophoresis with laser-induced fluorescent detection method using highly emissive probes for analysis of actinides in radioactive wastes - 59092  

International Nuclear Information System (INIS)

Actinides are important nuclides for the analysis of radioactive wastes arising from nuclear fuel cycle facilities. In order to achieve simple and rapid analysis of actinides, capillary electrophoresis-laser-induced fluorescent detection method (CE-LIF) is one of the potential candidates. In this study, new emissive probes of actinide ions suitable for CE-LIF were developed for the first time. The detection and separation of americium and neptunium ions as model nuclides were examined using several new emissive complexing probes, each of which possessed a fluoro-phore and a different chelating moiety. With a pre-capillary complexation technique without addition of the probe to separation buffer electrolyte, the highly sensitive fluorescent detection of Am and Np was successfully achieved using acyclic and macrocyclic multi-dentate probes. The results suggests that the probe with an acyclic hexa-dentate chelating moiety is suitable for detection and separation of Am and Np. The detection limit of mid-ppt levels was determined. (authors)

299

Radioactivity and foods  

International Nuclear Information System (INIS)

The purpose of this article is to describe and contrast two relationships between radiation and food-on the one hand, beneficial preservation of food by controlled exposure to ionizing radiation; and, on the other, contamination of food by accidental incorporation of radioactive nuclides within the food itself. In food irradiation, electrons or electromagnetic radiation is used to destroy microorganisms and insects or prevent seed germination. The economic advantages and health benefits of sterilizing food in this manner are clear, and numerous studies have confirmed that under strictly controlled conditions no undesirable changes or induced radioactivity is produced in the irradiated food. An altogether different situation is presented by exposure of food animals and farming areas to radioactive materials, as occurred after the major Soviet nuclear reactor accident at Chernobyl. This article furnishes the basic information needed to understand the nature of food contamination associated with that event and describes the work of international organizations seeking to establish appropriate safe limits for levels of radioactivity in foods. 14 refs, 4 tabs

300

Radioactivity and foods  

International Nuclear Information System (INIS)

The purpose of this article is to describe and contrast two relationships between radiation and food on the one hand, beneficial preservation of food by controlled exposure to ionizing radiation; and, on the other, contamination of food by accidental incorporation of radioactive nuclides within the food itself. In food irradiation, electrons or electromagnetic radiation is used to destroy microorganisms and insects or prevent seed germination. The economic advantages and health benefits of sterilizing food in this manner are clear, and numerous studies have confirmed that under strictly controlled conditions no undesirable changes or induced radioactivity is produced in the irradiated food. An altogether different situation is presented by exposure of food animals and farming areas to radioactive materials, as occurred after the major Soviet nuclear reactor accident at Chernobyl. This article furnishes the basic information needed to understand the nature of food contamination associated with that event and describes the work of international organizations seeking to establish appropriate safe limits for levels of radioactivity in foods

301

Optimization of beam and target combinations for hybrid reactor systems and for the fission-induced production of radioactive beams  

International Nuclear Information System (INIS)

This thesis work consists of two parts: a) theoretical, and b) experimental. We combine and use the high energy transport code LAHET, the low energy transport code MCNP, and the activation code CINDER. Our benchmarking calculations show that LAHET neglects the Coulomb dissociation for deuterons. By adding this missing term, we obtain a good agreement with the available data. We also conclude that LAHET describes well the data for isotope production yields if the ORNL fission model is employed for nuclei with Z>90. The 'default' RAL fission model gives too broad isotopic distributions and fails to reproduce the data in absolute value. We examine different combinations of beams, beam energies, spallation target and multiplying medium materials in order to optimize the neutron production, energy amplification and isotope production via neutron induced fissions. We show that the (d,xn) reactions could bring a number of important advantages when compared to the (p,xn) reactions. We conclude that the use of deuterons instead of protons should result in higher primary beam intensities, lower costs of the system and facilitate radioprotection problems. Within the SPIRAL Phase-II project at GANIL, we propose d(100 MeV)+Be?xn+U as an optimum combination for the production of neutron rich nuclei in the mass region 75?A?160. However, the production of tritium gas in the target-converter should be considered carefully. The use of heavier metal targets-converters may cause moetal targets-converters may cause more severe problems of radioprotection.Our experimental work is closely related to the theoretical investigations. We measure the complete proton spectra for 1.00 and 200 MeV deuteron induced reactions on 8 thin targets (Be, C, Al, Ni, Nb, Ta,, Pb and U) and in the angular region 8 deg C ? ?p ? 120 deg C. The experiments were carried at LNS (Saclay, France) and at NAC (Faure, South Africa). Good quality data (within 10% in absolute value and with 4-8 MeV energy threshold) support our improved LAHET physics modelling for (d,xp) and, consequently, for (d,xn) reactions. (author)

302

Radioactivity Monitoring of the Irish Environment 2007  

International Nuclear Information System (INIS)

This report presents the results of the environmental radioactivity monitoring programme carried out by the Radiological Protection Institute of Ireland (RPII) in 2007. This programme aims to assess the exposure of the Irish population to artificial radioactivity in the envorinment, to review the temporal and geographical distribution of contaminating radionuclides and to maintain systems and procedures which would allow a rapid assessment of environmental contamination to be made in the event of a radiological emergency. In additiopn, some natural radioactivity exposure pathways are included in the programme including radioactivity in surface and ground drinking water. Radioactivity is present in the environment due to natural oprocesses, the testing of nuclear weapons in the atmosphere, past nuclear accidents such as that at Chernobyl in the Ukraine and the routine discharge of radionuclides from nuclear installations. Liquid discharges from the British Nuclear Group reprocessing plant at Sellafield in Cumbria in the north-west of England continue to be the dominant source of artificial radioactivity in the Irish marine environment. The key elements of the monitoring programme implemented by the RPII in 2007 included; assessment of ambient radioactivity based on measurements of radioactivity in air and of external gamma dose rate at permanent monitoring stations located throughout the country; assessment of levels of radioactivity in drinking water; assessment of levels of radioactivity in foodstuffs based on measurements of total diet, milk and various ingredients; assessment of levels of radioactivity in the Irish marine environment based on sampling and measurement of seawater, sediment, seaweed, fish and shellfish. The RPII monitored airborne radioactivity at twelve stations located throughout the country. One of these stations is equipped with a high volume sampler, which allows background concentrations of caesium-137 to be measured; another is equipped to detect the presence of the gas krypton-85. This gas is released into the environment primarity as a result of the reprocessing of nuclear fuel. During 2007, levels of radionuclides in airborne radioactivity were low and consistent with measurements in previous years. External gamma dose rates were monitored continuously at fifteen stations. No abnormal levels were observed. A major upgrade of the aerosol sampling equipment began in 2007 when three on-line low volume systems and seven upgraded off-line low volume systems were installed and commissioned. Two additional on-line sites will be added in 2008. In accordance with the RPII's drinking water monitoring protocol, a number of major water supplies from Cork, Dublin, Galway and Limerick were tested and found to be within the requirements for radioactivity set out in the relevant national standards. In addition, groundwater supplies were tested in nine countries as a pilot for a national survey of ground water scheduled for 2008 to 2010. The RPII sampled and measured levels of radioactivity in mixed diet, milk and various other foodstuffs including milk products, baby foods, beef, lamb and poultry. These measurements show that the levels of artificual radioactivity in the Irish diet continue to be low. One hundred and ninety samples of fish, shellfish, seaweed, seawater and sediment were analysed for a range of radionuclides. Along the Irish coastline the highest activity concentrations observed were in the north-east. The main pathway contributing to the exposure of the Irish public to artificial radioactivity from the marine environment is the consumption of seafood. Caesium-137 continues to be the dominant radionuclide, accounting for approximately 84% of the total dose. The dose to the Irish population from consumption of seafood landed at north-east ports has declined significantly over the last two decades corresponding to the reduction in discharges from Sellafield. The annual doses incurred by the Irish public as a result of artificial radioactivity in the environment do not constitute a significant he

303

HUMAN EXPOSURE TO THE ARTIFICIAL RADIONUCLIDES IN ENVIRONMENT  

OpenAIRE

Artificial radionuclides are product of different human activities and their presence in the environment is negative side effect of civilization progress. They have been spread in the environment by events such as nuclear weapon tests, nuclear accidents and by deliberate and negligent discharge of radioactive waste from nuclear and other installation. Once released in to the nature, the artificial radionuclides start to circle in the same manner as naturally occurring ones, and finally they f...

Ivana Vukanac; Aleksandar Kandic; Mirjana Duraševic; Bojan Seslak

2012-01-01

304

Radioactive alchemy  

International Nuclear Information System (INIS)

For any entity involved in radioactive waste management, turning lead into gold means succeeding with minimising the volumes and optimizing the long-term containment of ultimate waste to be disposed of. With this purpose, they perform R and D on different sorting, treatment and disposal technology, as explained by Frederic Plas from Andra (France), Jan Deckers from Belgoprocess (Belgium) and Wilhelm Bollingerfehr from DBE Technology (Germany). (orig.)

305

From Polonium to Artificial Radioisotopes in the 1930's  

Science.gov (United States)

The word ``radioactive'' appeared for the first time in Pierre and Marie Curie's paper announcing the discovery of Polonium. Starting with the memory of this seminal event and the discovery of Radium, we focus on a few of the tremendous successes achieved in the 30's, namely the successive discoveries of the neutron and the positive electron, followed by the discoveries of artificial radioactivity and later of fission. Experimentalists were confronted with many problems as their interest shifted from radioactivity to ``artificial disintegration'' and cosmic rays experiments. The first discovered beta + radioactive isotopes, 30P and 13N, and the first fission produced nuclei appear as early steps towards the quest for more and more exotic nuclei.

Langevin-Joliot, H.

2007-04-01

306

Radioactivity in Hocking River Basin  

International Nuclear Information System (INIS)

Numerous studies have examined the environmental impacts and health hazards associated with man-made radioactive pollution. Within the last decade, however, there has been a growing awareness of the natural radiation environment. Very little is know about the way the natural radiation environment is affected when subjected to artificial stresses imposed by man's activities. The prolonged exposure from low level radioactivity may significantly affect our environment by altering the distribution of naturally occurring radionuclides through such processes as mining, water resources management or land reclamation. It is the intent of this study to examine more closely the way in which this radiological burden is altered by coal mining activities in an Appalachian watershed

307

A Light Driven Artificial Goldfish  

Science.gov (United States)

Liquid crystalline elastomers (LCEs) undergo large and rapid shape changes when illuminated by light. We have immersed an azo-dye doped LCE in a fluid and alternately illuminate either side of the LCE with light to create an artificial goldfish of sorts. These light induced deformations allow the LCE to interact with a fluid environment in novel ways. We use a fluid flow visualization technique to attempt to understand the dynamics of these interactions. We describe our experimental setup, the LCE drive scheme used, and our observations of induced motion in both the LCE sample and the surrounding fluid.

Neal, J.; Finkelmann, H.; Palffy-Muhoray, P.; Shelley, M.; Toth-Katona, T.

2005-03-01

308

Molecular recognition and organizational and polyvalent effects in vesicles induce the formation of artificial multicompartment cells as model systems of eukaryotes.  

Science.gov (United States)

Researchers have become increasingly interested in the preparation and characterization of artificial cells based on amphiphilic molecules. In particular, artificial cells with multiple compartments are primitive mimics of the structure of eukaryotic cells. Endosymbiotic theory, widely accepted among biologists, states that eukaryotic cells arose from the assembly of prokaryotic cells inside other cells. Therefore, replicating this process in a synthetic system could allow researchers to model molecular and supramolecular processes that occur in living cells, shed light on mass and energy transport through cell membranes, and provide a unique, isolated space for conducting chemical reactions. In addition, such structures can serve as drug delivery systems that encapsulate both bioactive and nonbiocompatible compounds. In this Account, we present various coating, incubation, and electrofusion strategies for forming multicompartment vesicle systems, and we are focusing on strategies that rely on involving molecular recognition of complementary vesicles. All these methods afforded multicompartment systems with similar structures, and these nanoparticles have potential applications as drug delivery systems or nanoreactors for conducting diverse reactions. The complementarity of interacting vesicles allows these artificial cells to form, and the organization and polyvalency of these interacting vesicles further promote their formation. The incorporation of cholesterol in the bilayer membrane and the introduction of PEG chains at the surface of the interacting vesicles also support the structure of these multicompartment systems. PEG chains appear to destabilize the bilayers, which facilitates the fusion and transport of the small vesicles to the larger ones. Potential applications of these well-structured and reproducibly produced multicompartment systems include drug delivery, where researchers could load a cocktail of drugs within the encapsulated vesicles, a process that could enhance the bioavailability of these substances. In addition, the production of artificial cells with multiple compartments provides a platform where researchers could carry out individual reactions in small, isolated spaces. Such a reactive space can avoid problems that occur when the environment can be destructive to reactants or products or when a diverse set of compounds difficult to obtain in a conventional reactor space are produced. Our work on these artificial cells with multicompartment structures also led us to formulate a hypothesis on the processes that possibly generated eukaryotic cells. We hope both that our research efforts will excite interest in these nanoparticles and that this research could lead to systems designed for specific scientific and technological applications and further insights into the evolution of eukaryotic cells. PMID:24735049

Paleos, Constantinos M; Pantos, A

2014-05-20

309

Radioactivity and fusion energy  

International Nuclear Information System (INIS)

Nuclear fusion is expected to give an ultimate solution to energy problems over the long term. From recent progress in developing technology for fusion reactors, we can anticipate a prototype fusion reactor by 2030. This review article describes the present status of nuclear fusion research, including muon catalyzed fusion (?CF) which attracts quite new physical interest. Tritium is an essential component of fusion reactors, because the first-stage fusion reactors will utilize a mixture of deuterium and tritium as their fuel. The knowledge about tritium as well as the fusion-neutron induced radioactivity is summarized in terms of nuclear fusion research. (orig.)

310

Radioactivity and fussion energy  

International Nuclear Information System (INIS)

Nuclear fusion is expected to give an ultimate solution to energy problems over the long term. From recent progress in developing technology for fusion reactors, we can anticipate a prototype fusion reactor by 2030. This review article describes the present status of nuclear fusion research, including muon catalyzed fusion (mu CF) which attracts quite new physical interest. Tritium is an essential component of fusion reactors, because the first-stage fusion reactors will utilize a mixture of deuterium and tritium as their fuel. The knowledge about tritium as well as the fusion-neutron induced radioactivity is summarized in terms of nuclear fusion research. (author)

311

Uranium and radioactivity  

International Nuclear Information System (INIS)

The article gives results of investigations on uranium content and the proportion of induced and natural radioactivity in wines of different vines and regions. The ecological chain of ground, vine, grape, grape-juice, and wine is described, and the author shows that 14C and T measurements can be used to determine the age of wines with the aim of detecting adulterated vintages and blends of different years. The 14C and T content also indicates a direct connection with nuclear explosions. (RB/AK)

312

Ambiant natural radioactivity and cancer  

International Nuclear Information System (INIS)

Measures made in France have showed that ? radioactivity and indoor radon concentration were more important in country with granitic soil. As long as radon was more particularly admitted to be inducer of broncho-pulmonary cancer by inhalation, epidemiologic inquiries were made. The results do not reveal any excess death caused by cancer in these countries selected because of their granitic soil

313

Radioactive wastes  

International Nuclear Information System (INIS)

A review is presented on the environmental behavior of radioactive wastes. The management of high-level wastes and waste disposal methods were discussed. Some topics included were ore processing, coagulation, absorption and ion exchange, fixation, ground disposal, flotation, evaporation, transmutation and extraterrestrial disposal. Reports were given of the 226Ra, 224Ra and tritium activity in hot springs, 90Sr concentrations in the groundwater and in White Oak Creek, radionuclide content of algae, grasses and plankton, radionuclides in the Danube River, Hudson River, Pacific Ocean, Atlantic Ocean, Lake Michigan, Columbia River and other surface waters. Analysis showed that 239Pu was scavenged from Lake Michigan water by phytoplankton and algae by a concentration factor of up to 10,000. Benthic invertebrates and fish showed higher 239Pu concentrations than did their pelagic counterparts. Concentration factors are also given for 234Th, 60Co, Fe and Mr in marine organisms. Two models for predicting the impact of radioactivity in the food chain on man were mentioned. In an accidental release from a light-water power reactor to the ocean, the most important radionuclides discharged were found to be 90Sr, 137Cs, 239Pu and activation products 65Zr, 59Fe, and 95Zr

314

Cluster Radioactivity  

Science.gov (United States)

One of the rare examples of phenomena predicted before experimental discovery, offers the opportunity to introduce fission theory based on the asymmetric two center shell model. The valleys within the potential energy surfaces are due to the shell effects and are clearly showing why cluster radioactivity was mostly detected in parent nuclei leading to a doubly magic lead daughter. Saddle point shapes can be determined by solving an integro-differential equation. Nuclear dynamics allows us to calculate the half-lives. The following cluster decay modes (or heavy particle radioactivities) have been experimentally confirmed: 14C, 20O, 23F, 22,24-26Ne, 28,30Mg, 32,34Si with half-lives in good agreement with predicted values within our analytical superasymmetric fission model. The preformation probability is calculated as the internal barrier penetrability. An universal curve is described and used as an alternative for the estimation of the half-lives. The macroscopic-microscopic method was extended to investigate two-alpha accompanied fission and true ternary fission. The methods developed in nuclear physics are also adapted to study the stability of deposited atomic clusters on the planar surfaces.

Poenaru, Dorin N.; Greiner, Walter

315

From Artificial Evolution to Artificial Life  

OpenAIRE

This work addresses the question: What are the basic design considerations for creating a synthetic model of the evolution of living systems (i.e. an `artificial life' system)? It can also be viewed as an attempt to elucidate the logical structure (in a very general sense) of biological evolution. However, with no adequate definition of life, the experimental portion of the work concentrates on more specific issues, and primarily on the issue of open-ended evolution. An artificial...

Taylor, Timothy J.

1999-01-01

316

Radioactivity of some alpha, beta and gamma emitting radionuclides in surface marine sediments of different bays in Algeria  

International Nuclear Information System (INIS)

Samples of surface (0-15) cm marine sediments of different grain sizes, namely sand, muddy and fine sand, were collected in the western, central and east coast of Algeria, to measure concentrations of natural and artificial radioactivity. The aim of this study is to detect any radioactive contamination, its origin and also to determine the uptake of radioactivity by marine surface sediments

317

Ambient radioactivity levels and radiation doses. Annual report 2011; Umweltradioaktivitaet und Strahlenbelastung. Jahresbericht 2011  

Energy Technology Data Exchange (ETDEWEB)

The annual report 2011 on ambient radioactivity levels and radiation doses covers the following issues: Part A: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. Part B; Current data and their evaluation: Natural environmental radioactivity, artificial radioactivity in the environment, occupational radiation exposure, radiation exposure from medical applications, the handling of radioactive materials and sources of ionizing radiation, non-ionizing radiation. The Appendix includes Explanations of terms, radiation doses and related units, external and internal radiation exposure, stochastic and deterministic radiation effects, genetic radiation effects, induction of malignant neoplasm, risk assessment, physical units and glossary, laws, ordinances, guidelines, recommendations and other regulations concerning radiation protection, list of selected radionuclides.

Bernhard-Stroel, Claudia; Hachenburger, Claudia; Trugenberger-Schnabel, Angela; Peter, Josef (comps.) [Bundesamt fuer Strahlenschutz, Salzgitter (Germany)

2013-07-15

318

Radioactive tracer  

International Nuclear Information System (INIS)

Transport of the European coastal waters from the English Channel along the coasts of France, Netherlands, Germany and West Jutland into Kattegat is studied in this project, within the EC marine research program MAST (Marine Science and Technology). The project is generally based on measuring of the radioactive technetium-99 (99Tc) released by the French nuclear plants La Hague near Cherbourg. The concentration of 99Tc in the bottom waters of Kattegat is proved to vary far more than that in the German Bay. Our explanation of these variations contributes to the following theory: bottom water flowing into Kattegat from Skagerrak arrives from different water masses. One of those is the Jutland Coastal Current, transporting European coastal waters with relatively high pollution into Skagerrak and Kattegat. Around 15% of a conservative release from La Hauge is passing through Kattegat compared to a similar release into the Irish Sea. (EG)

319

Nuclear physics with radioactive beams  

International Nuclear Information System (INIS)

Radioactive beams can be produced through two different and complementary ways:i. the production at rest of radioactive nuclei, followed by their acceleration using conventional techniques.This method is the best for producing low energy radioactive beams. ii. the fragmentation of high energy heavy ion beams ( over 30 MeV/u), followed by the selection and purification of a given secondary beam using magnetic spectrometers. This technique leads to high energy radioactive beams. Both methods have now been used in several laboratories in the world. Examples of the corresponding experimental equipment will be presented, and especially Lise 3, Sissi, and the spiral project at GANIL. Radioactive beams have used for several purposes in nuclear physics: i. they constitute the fastest technique ever used for transferring exotic nuclei from the production point to a well shielded place where detectors can be operated for studying their properties in good conditions. At the same time, they can be identified using solid state detectors and the time-of-flight/energy-loss technique. Illustrations of the results obtained in this domain (mass and half-life measurements, recent identification of the isotope sup 1 sup 0 sup 0 Sn) is given. ii. they are used to induce nuclear reactions which may bring new information on nuclear structure. For example, the measurement of total reaction cross-sections for many radioactive projectiles revealed the existence of halo nuclei such as sup 1 supexistence of halo nuclei such as sup 1 sup 1 Li and sup 1 sup 1 Be. Beams of these isotopes have been extensively used to precise their structure.iii. in the domain of nuclear astrophysics, radioactive beams are used to measure, through direct or indirect methods, the cross sections for reactions of crucial interest in nucleosynthesis. Finally, radioactive beams of light positron emitters, such as sup 1 sup 9 Ne have considerable interest for medical purposes and especially in the growing field of heavy-ion radiotherapy. 8 figs., 24 refs. (author)

320

Radioactive colloids  

International Nuclear Information System (INIS)

Different techniques for the characterization of radioactive colloids, used in nuclear medicine, have been evaluated and compared. Several radioactive colloids have been characterized in vitro and in vivo and tested experimentally. Colloid biokinetics following interstitial or intravenous injection were evaluated with a scintillation camera technique. Lymphoscintigraphy with a Tc-99-labelled antimony sulphur colloid was performed in 32 patients with malignant melanoma in order to evaluate the technique. Based on the biokinetic results, absorbed doses in tissues and organs were calculated. The function of the reticuloendothelial system has been evaluated in rats after inoculation with tumour cells. Microfiltration and photon correlation spectroscopy were found to be suitable in determining activity-size and particle size distributions, respectively. Maximal lymph node uptake following subcutaneous injection was found to correspond to a colloid particle size between 10 and 50 nm. Lymphoscintigraphy was found to be useful in the study of lymphatic drainage from the primary tumour site in patients with malignant melanoma on the trunk. Quantitative analysis of ilio-inguinal lymph node uptake in patients with malignant melanoma on the lower extremities was, however, found to be of no value for the detection of metastatic disease in lymph nodes. High absorbed doses may be received in lymph nodes (up to 1 mGy/MBq) and at the injection site (about 10 mGy/MBq). In an experimental study it was found that the relative colloid uptake in bone marrow and spleen depended on the total number of intravenously injected particles. This may considerably affect the absorbed dose in these organs. (author)

321

Environmental radioactivity and radiation doses in Switzerland 1992  

International Nuclear Information System (INIS)

This report summarises the 1992 results of the environmental radioactivity monitoring programme together with interpretation and outcoming radiation exposure of the Swiss population. The surveillance programme includes radioactivity of air, rain, surface water, soil, vegetation, food, etc. as well as natural radioactivity, exposure by radon in dwellings, radioactivity released to the environment by nuclear installations and other enterprises processing radioisotopes and further radiation sources. In 1992, Swiss nuclear power stations and industrial plants licensed to process radionuclides respected their limits for radioactivity release to the environment, and no inadmissible concentrations or ambient doses have been detected in the surroundings. The mean radiation exposure of the public amounted, as in the previous years, to approximately 4.6 mSv per year. Thereof 2.2 mSv derived from natural radon in dwellings whereas the total artificial radioactivity without that from medical applications yielded less than 0.2 mSv per year. (author) figs., tabs., refs

322

HUMAN EXPOSURE TO THE ARTIFICIAL RADIONUCLIDES IN ENVIRONMENT  

Directory of Open Access Journals (Sweden)

Full Text Available Artificial radionuclides are product of different human activities and their presence in the environment is negative side effect of civilization progress. They have been spread in the environment by events such as nuclear weapon tests, nuclear accidents and by deliberate and negligent discharge of radioactive waste from nuclear and other installation. Once released in to the nature, the artificial radionuclides start to circle in the same manner as naturally occurring ones, and finally they fall out from air and water onto the ground and build into the foodstuff and drinking water resulting in radiation doses to human beings. The short overview of presence of artificial radioactivity in human environment and its impact on human life is presented in this paper.

Ivana Vukanac

2012-09-01

323

Artificial cognition architectures  

CERN Document Server

The goal of this book is to establish the foundation, principles, theory, and concepts that are the backbone of real, autonomous Artificial Intelligence. Presented here are some basic human intelligence concepts framed for Artificial Intelligence systems. These include concepts like Metacognition and Metamemory, along with architectural constructs for Artificial Intelligence versions of human brain functions like the prefrontal cortex. Also presented are possible hardware and software architectures that lend themselves to learning, reasoning, and self-evolution

Crowder, James A; Friess, Shelli A

2013-01-01

324

Artificial Intelligence in Astronomy  

Science.gov (United States)

From the perspective (and bias) as Eclipsing Binary researchers, we give a brief overview of the development of Artificial Intelligence (AI) applications, describe major application areas of AI in astronomy, and illustrate the power of an AI approach in an application developed under the EBAI (Eclipsing Binaries via Artificial Intelligence) project, which employs Artificial Neural Network technology for estimating light curve solution parameters of eclipsing binary systems.

Devinney, E. J.; Prša, A.; Guinan, E. F.; Degeorge, M.

2010-12-01

325

Radioactivity for man's benefit  

International Nuclear Information System (INIS)

Nuclear medicine is the application of radionuclides in the diagnosis and treatment of disease. The workhorse of nuclear medicine is the artificially produced radionuclide technetium-99m (Tc-99m). Tc-99m is employed as a radioactive label for many different compounds used to study various organs. Using these compounds it has become possible to image organ structure, organ function and the disturbance of organ function. The utilization of radionuclides in medical research in the Republic of South Africa has been actively supported since 1959 by mainly three organizations, namely the South African Medical Research Council, the Council for Scientific and Industrial Research and the Atomic Energy Corporation of South Africa. This support, together with the consistency of the production of valuable radionuclides, has made it possible for those centres which have nuclear medicine facilities to conduct research of international standing. This research includes studies on cancer, liver and kidney transplants, the heart, diabetes and blood platelet kinetics. The National Accelerator Centre at Faure in the Cape is now poised to produce radionuclides hetherto unavailable in the Republic of South Africa. This will enable exciting new techniques such as Positron emission tomography to become a reality. 1 fig

326

Artifacts and Artificial Science  

OpenAIRE

In the Spring of 1968, Herbert Simon gave a series of lectures at Massachusetts Institute of Technology, introducing his idea of a science of the artificial. “The world we live in today is much more a man-made, or artificial, world than it is a natural world,” he began to say, but modern science is a science of nature. “Natural science is knowledge about natural objects and phenomena. We ask whether there cannot also be “artificial” science–knowledge about artificial objects and p...

Beckman, Svante; Nilsson, Go?ran B.; Dahlbom, Bo

2002-01-01

327

Environmental radioactivity and radiation exposure  

International Nuclear Information System (INIS)

The environmental radioactivity in the Federal Republic of Germany was almost as high in 1976 as in 1975. It only increased temporarily in autumn 1976 as a result of the above-ground nuclear weapons test of the People's Republic of China on September 29th 1976 and then returned to its previous level. The radioactivity in food had a slight decreasing trend in 1976, apart from a temporary increase in the radioactivity in milk also caused by the nuclear weapons test mentioned. The population exposure remains basically unchanged in 1976 compared with 1975. The artificial radiation exposure is about half as high as the natural radiation exposure to which man has always been exposed. The former is based to 83% on using X-rays in medicine, particularly for X-ray diagnostic purposes. The population exposure due to nuclear power plants and other nuclear plants is still well below 1% of the natural radiation exposure although in 1976 three new nuclear power plants were put into operation. This is also true for the average radiation exposure within an area of 3 km around the nuclear plant. (orig.)

328

Radioactivity in the Great Lakes.  

Science.gov (United States)

Studies of radioactivity in the Laurentian Great Lakes are reviewed to evaluate the impact of radionuclide dissemination on the world's foremost freshwater aquatic ecosystem. The status of radiologically-degraded areas is also reported. Significant amounts of radioactivity are stored in the basin, which has numerous nuclear reactors as well as uranium mine waste areas. The prevailing low levels of artificially-produced radionuclides, arising largely from previous fallout inputs, provide very little radiation dose to the area residents consuming lake water. The interlake transport of radionuclides is adequately described by existing models, though some refinement of the source term is needed. Revised estimates of fallout over each lake are given, but no data are available to estimate drainage basin contributions. Only limited information is available on the dispersal of radioactive pollutants. The influence of chemical parameters on radionuclide cycling has been extensively investigated in Lake Michigan and, to a lesser degree, in Lake Ontario. The need for developing a radiological objective for fish becomes apparent from an assessment of the very few data collected thus far on the biological and dosimetric aspects. Several research and monitoring needs are also identified. PMID:2063188

Joshi, S R

1991-03-01

329

Artificial extracellular matrix composed of collagen I and highly sulfated hyaluronan interferes with TGF?(1) signaling and prevents TGF?(1)-induced myofibroblast differentiation.  

Science.gov (United States)

Sulfated glycosaminoglycans are promising components for functional biomaterials since sulfate groups modulate the binding of growth factors and thereby influence wound healing. Here, we have investigated the influence of an artificial extracellular matrix (aECM) consisting of collagen I (coll) and hyaluronan (HA) or highly sulfated HA (hsHA) on dermal fibroblasts (dFb) with respect to their differentiation into myofibroblasts (MFb). Fibroblasts were cultured on aECM in the presence of aECM-adsorbed or soluble transforming growth factor ?1 (TGF?1). The synthesis of ?-smooth muscle actin (?SMA), collagen and the ED-A splice variant of fibronectin (ED-A FN) were analyzed at the mRNA and protein levels. Furthermore, we investigated the bioactivity and signal transduction of TGF?1 in the presence of aECM and finally made interaction studies of soluble HA or hsHA with TGF?1. Artificial ECM composed of coll and hsHA prevents TGF?1-stimulated ?SMA, collagen and ED-A FN expression. Our data suggest an impaired TGF?1 bioactivity and downstream signaling in the presence of aECM containing hsHA, shown by massively reduced Smad2/3 translocation to the nucleus. These data are explained by in silico docking experiments demonstrating the occupation of the TGF?-receptor I binding site by hsHA. Possibly, HA sulfation has a strong impact on TGF?1-driven differentiation of dFb and thus could be used to modulate the properties of biomaterials. PMID:23602877

van der Smissen, Anja; Samsonov, Sergey; Hintze, Vera; Scharnweber, Dieter; Moeller, Stephanie; Schnabelrauch, Matthias; Pisabarro, M Teresa; Anderegg, Ulf

2013-08-01

330

Increase of radon concentration and its decay products in the zone of electric discharge in different media - the source of false effects of induced radioactivity  

International Nuclear Information System (INIS)

It is shown that in some cases when working with electrical discharges in different environments the appearance of radioactivity and helium traces may be a result of increase concentration of 222Rn natural radon and its decay products in the discharge area.

331

Radioactivity of the Treated Topaz  

International Nuclear Information System (INIS)

Raw topaz stone samples are subjected to irradiation by neutrons from the Egyptian second research reactor and by gamma (?) rays from a gamma source. Changes in the color of the stones are observed. Irradiation induces radionuclides, resulting to radioactivity. Therefore, some time is required for the radioactivity level of stones to fall to exempted value; hence, radioactivity of the stones after irradiation has to be followed and monitored till their release from the reactor. Storage time might be several months to several years. The decay rates of isotopes created by irradiation depend on the individual isotope. Neutron-irradiated topaz treated in a nuclear reactor facility can present a potential health hazard, if not properly controlled. A special license is required for transportation and distribution of such treated gem stones, because radiation exposures associated. Experience gained in management of irradiated topaz shall be reviewed

332

Radioactive monitoring of the marine environment  

International Nuclear Information System (INIS)

Radioactivity monitoring of marine environment was required by the development of nuclear power and the worldwide use of ionizing radiations in many different activities. Both natural and artificial radioactivity play an important role in marine ecology and human health. In respect of this, three major facts prevail, namely: the fallout, the proximity of Danube River and the future nuclear power production. Spatial and temporal monitoring of marine radioactivity along the Romanian Black Sea shore has been systematically performed in Romanian Marine Research Institute in close cooperation with Institute of Meteorology and Hydrology since 1981. Marine emerged and submerged sediments, coastal and offshore sea water, macroalgae, invertebrates and fish of Danube mouths and/or along the coast are monitored for natural and artificial radioactivity by means of gross beta measurements and gamma spectrometry. Concentrations of radionuclides such as: K-40, Cs-134 and Cs-137 in abiotic and biotic samples, environmental distribution coefficients and concentration factors (CFs) as well as experimentally derived CFs in marine biota as radioecological bioindicators are assessed and stored in a national data base. (author)

333

Monitoring of radioactivity in the marine environment  

International Nuclear Information System (INIS)

The necessity of radioactivity monitoring in the marine environment was imposed by the increasing development of nuclear power and its world-wide use in many different segments of economic and social life. Both natural and artificial radioactivity play an important role in marine ecology and human health. In this respect three major facts continue to prevail in Romania. The fallout, the presence of the Danube river and the expectations for future energy production. Spatial and temporal monitoring of marine radioactivity along the Romanian Black Sea shore has been systematically performed in the Romanian Marine Research Institute in close co-operation with the Institute of Meteorology and Hydrology since 1981. Marine emerged and submerged sediments, coastal and offshore sea water, macroalgae, in vertebrates and fish off the Danube mouths and/or along the coast are monitored for natural and artificial radioactivity by means of beta gross measurements and gamma spectrometry. Concentrations of radionuclides as K-40, Cs-134, Cs-137 in abiotic and biotic samples, environmental distributions coefficients and concentrations factors (CF), as well as experimentally-derived CFs in marine biota as radioecological bioindicators are assessed and stored for a national data base. (author) 3 tabs., 18 refs

334

[Artificial urinary sphincter].  

Science.gov (United States)

The artificial urinary sphincter is a totally implantable hydraulic prosthesis designed to restore continence without inducing dysuria. It is composed of 3 silicone elastomer elements: a periurethral or pericervical cuff, a pressure regulating reservoir balloon inserted in the retropubic space, and a pump situated in the scrotum or labia majora. The prosthesis is filled with a liquid containing a contrast agent. Pressure on the pump allows passage of liquid from the cuff towards the balloon and allows micturition. After 3 to 4 minutes, the liquid is automatically transferred from the balloon to the cuff to restore continence. The artificial sphincter is currently a very effective therapeutic solution in cases of severe urinary incontinence with 3 main indications: persistent incontinence after prostatic surgery, recurrent incontinence in women due to sphincter insufficiency, and certain forms of neurogenic incontinence. The Pitié-Salpêtrière Urology Department's experience currently consists of 200 implantations performed over the last 10 years. The overall success rate varies from 80 to 90% according to sex and the aetiology of incontinence, in patients in whom the sphincter remains in place. In fact, there is a risk of explantation due to erosion of the tissues by the cuff or infection, but this risk is less than 15%. The risk of prosthesis failure is about 20%, but after correction of the defective element, cure is achieved in almost every case. Analysis of the results in the first 120 patients with the two most frequent aetiologies and with at least three years' follow-up (range: 3 to 10 years) reveals: in a series of 75 men, treated for severe incontinence persisting more than one year after surgery for benign prostatic hyperplasia, the explantation rate was 15% and, in the patients in whom the sphincter remained in place, complete cure was obtained in 73% of cases without any incontinence, while 17% of patients suffered from minimal incontinence, not requiring protection, 7% had moderate incontinence requiring protection and 3% were considered to be failures. The revision rate for technical failure was 24%. In a series of 45 women with recurrent incontinence after surgery, due to sphincter insufficiency, the explanation rate was 13% and, in women in whom the sphincter remained in place, complete success was obtain in 78% of cases without any incontinence, while 17% suffered from minimal incontinence, usually not requiring protection, 5% require protection, with no failures and a revision rate for technical failure of 24%.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7648305

Chatelain, C; Richard, F; Bitker, M O

1995-03-01

335

Radiation protection. Radioactivity and health. 3. ed.  

International Nuclear Information System (INIS)

This booklet makes an attempt at elucidating the mutual influence of radioactivity and health in a way which is understandable to the non-expert. The basics of radioactivity are briefly explained by way of introduction, the next item to be described is exposure of man to natural and artificial radiation. Somatic and genetic effects of radiation on man are subsequently discussed. The whole area of radioecology - starting with radioactive discharge from nuclear plants and going on to the determination of man's exposure to radiation - is covered and supplemented by a description of the risks of radiation therapy. All this serves to describe the results of long-term research on questions of the radiobiological risks in an understandable way and provide useful information about this eminently important area. (orig.)

336

Radioactivity and Nuclear Issues in Science Fiction  

International Nuclear Information System (INIS)

In this work are presented and reviewed science fiction narratives, films and comics that exploit radioactivity and nuclear issues. These topics to some science fiction authors serve as metaphor of evil and holocaust as well as nice instrument for elaborating various manipulations and conspiracy theories. In that context are of special interest science fiction works depicting apocalyptic post-nuclear worlds and societies, such works being closely connected with cyberpunk genre. However, other more technologically optimistic authors nuclear energy and research regarding nuclear technology and radioactivity consider as eligible and inevitable solution for world peace and prosperity Nowadays, public interest and global fears are shifted from radioactivity and nuclear issues to other catastrophic scenarios threatening future of the mankind, these for example being climate changes and global warming, asteroid impact, collapse of information infrastructure, nanotechnology, robotics and artificial intelligence etc. Consequently, these issues are as well increasingly reflected in contemporary science fiction stories.(author)

337

Radioactive waste and transport. Chapter 6  

International Nuclear Information System (INIS)

A brief definition of the nature of radioactive waste is followed by a more detailed discussion of high level waste, its composition the amounts involved, storage in liquid and in solid form and the storage of non-reprocessed spent fuel. The final disposal of high level waste in deep geological structures is then described, based on the Swedish KBS study. The effectiveness of the artificial and natural barriers in preventing the radioactive substances from reaching the biosphere is discussed. American and Swedish risk analyses are briefly discussed, and practical experience presented. Low and medium level wastes are thereafter treated in a similar, though briefer manner. Transport of radioactive materials, fresh fuel, spent fuel and waste is then dealt with. Regulations for the containers and their tests are briefly presented and the risk of accidents, theft and sabotage during transport are discussed. (JIW)

338

Radioactive waste management  

International Nuclear Information System (INIS)

Radioactive waste generated from utilization of radioisotopes and each step of the nuclear fuel cycle and decommissioning of nuclear facilities are presented. On the safe management of radioactive waste management, international safety standards are established such as ''The Principles of Radioactive Waste Management (IAEA)'' and The Joint Convention on the Safety of Radioactive Waste Management. Basic steps of radioactive waste management consist of treatment, conditioning and disposal. Disposal is the final step of radioactive waste management and its safety is confirmed by safety assessment in the licensing process. Safety assessment means evaluation of radiation dose rate caused by radioactive materials contained in disposed radioactive waste. The results of the safety assessment are compared with dose limits. The key issues of radioactive waste disposal are establishment of long term national strategies and regulations for safe management of radioactive waste, siting of repository, continuity of management activities and financial bases for long term, and security of human resources. (Author)

339

Measurement network for atmospheric radioactivity managed by ASPA  

International Nuclear Information System (INIS)

It was after the Chernobyl accident that a management committee of the radioactivity in Alsace has been put in place (composed of representatives from state, local governments, scientific organizations and associations). This committee entrusted ASPA to manage a measurement network for radioactivity in Alsace composed of 5 stations. ASPA provides automatic communication of results hourly on its web-site www.atmo-alsace.net/site/Radioactivite-13.html to enable its members and the public to have at any time information of artificial radioactivity in air in Alsace. In case of validated alarm, ASPA performs further analysis, meets the surveillance group and complete information through special announcements. (author)

340

Survey monitoring of environmental radioactivity in Daejeon area  

Energy Technology Data Exchange (ETDEWEB)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Daejeon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Daejeon Radiation Monitoring Station in 2002. In conclusion, the natural environmental radiation level in Daejeon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period.

Jun, Jae Shik; Noh, Hyung Ah [Daejon Radiation Monitoring Station, Daejeon (Korea, Republic of)

2003-12-15

341

Survey monitoring of environmental radioactivity in Daejeon area  

Energy Technology Data Exchange (ETDEWEB)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Daejeon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Daejeon Radiation Monitoring Station in 2002. In conclusion, the natural environmental radiation level in Daejeon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period.

Jun, Jae Shik; Noh, Hyung Ah [Daejon Radiation Monitoring Station, Daejeon (Korea, Republic of)

2002-12-15

342

Survey monitoring of environmental radioactivity in Daejeon area  

International Nuclear Information System (INIS)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Daejeon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Daejeon Radiation Monitoring Station in 2002. In conclusion, the natural environmental radiation level in Daejeon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period

343

Survey monitoring of environmental radioactivity in Daejeon area  

International Nuclear Information System (INIS)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Taejon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Taejon Radiation Monitoring Station in 2000. In conclusion, the natural environmental radiation level in Taejon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period

344

Survey monitoring of environmental radioactivity in Daejeon area  

Energy Technology Data Exchange (ETDEWEB)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Daejeon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Daejeon Radiation Monitoring Station in 2001. In conclusion, the natural environmental radiation level in Daejeon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period.

Jun, Jae Sik; Noh, Hyung Ah [Daejon Radiation Monitoring Station, Daejeon (Korea, Republic of)

2001-12-15

345

Survey monitoring of environmental radioactivity in Daejeon area  

International Nuclear Information System (INIS)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Daejeon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Daejeon Radiation Monitoring Station in 2001. In conclusion, the natural environmental radiation level in Daejeon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period

346

Survey monitoring of environmental radioactivity in Daejeon area  

Energy Technology Data Exchange (ETDEWEB)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Taejon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Taejon Radiation Monitoring Station in 2000. In conclusion, the natural environmental radiation level in Taejon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period.

Jun, Jae Shik.; Noh, Hyung Ah [Taejon Radiation Monitoring Station, Daejeon (Korea, Republic of)

2000-12-15

347

Survey monitoring of environmental radioactivity in Daejeon area  

International Nuclear Information System (INIS)

Systematic understanding of the distribution of environmental radioactivity and radiation level in Taejon, including Chungchung area, in normal circumstance, and rapid detection of unusual variation of the radiation level in emergency situation thereby ensure public safety are the objectives of this project to be carried out. This report summarizes and interprets environmental radiation/radioactivity monitoring data obtained at Taejon Radiation Monitoring Station in 1998. In conclusion, the natural environmental radiation level in Taejon area has been preserved as usual and no significant artificial enhancement in environmental radioactivity was observed during the course of this survey and monitoring period

348

The role of chemistry in the history of radioactivity (1897-1939)  

International Nuclear Information System (INIS)

Chemical research on radioactivity started in 1898. That year, Pierre and Marie Curie discovered in pitchblende polonium and radium. Rutherford and Soddy showed that radioactivity is an atomic phenomenon accompanied by transmutation of elements and established the basic laws of radioactive changes. The existence of isotopes was postulated after the discovery of many radioactive substances. Major discoveries in nuclear science, i.e. the atomic nucleus, the neutron and artificial radioactivity, were made with radiation sources elaborated bu chemists. Finally, in 1939, radiochemists on the search for transuranium elements, discovered nuclear fission. (authors)

349

On the modification of nuclear chronometry methods in astrophysics and geophysics induced by excited states of alpha radioactive nuclei and gamma emission  

International Nuclear Information System (INIS)

In practically all methods of nuclear chronometry known till now, were the lifetimes of only fundamental states for decaying ?-radioactive nuclei usually taken into account. But in the processes of nuclear synthesis in stars and under the influence of the constant cosmic radiation on the surfaces of planets, also the excited ?-radioactive nuclei appear. Between them, there are the states with the excited ?-particles inside the parent nuclei. They have much smaller lifetimes relative to the Geiger and Nutall law. And inside the large masses of stellar, terrestrial and meteoric substances, the transitions between different excited radioactive nuclei are accompanied by infinite chains of the ?-radiations with the subsequent ?-absorptions, the further ?-radiations etc. We must describe the ?-decay evolution, considering such excited states and multiple ?-radiations and ?-absorptions inside stars and also under the influence of the cosmic radiation on the earth surface. We present the quantum-mechanical approach, which is based on the generalized Krylov–Fock theorem. Some simple estimations are presented. They give rise to the conclusion that the usual (non-corrected) "nuclear clocks" do not really indicate the realistic values but the upper limits of the durations of the ?-decay stellar and planet processes. (author)

350

On the modification of nuclear chronometry methods in astrophysics and geophysics induced by excited states of alpha radioactive nuclei and gamma emission  

Science.gov (United States)

In practically all methods of nuclear chronometry known till now, were the lifetimes of only fundamental states for decaying ?-radioactive nuclei usually taken into account. But in the processes of nuclear synthesis in stars and under the influence of the constant cosmic radiation on the surfaces of planets, also the excited ?-radioactive nuclei appear. Between them, there are the states with the excited ?-particles inside the parent nuclei. They have much smaller lifetimes relative to the Geiger and Nutall law. And inside the large masses of stellar, terrestrial and meteoric substances, the transitions between different excited radioactive nuclei are accompanied by infinite chains of the ?-radiations with the subsequent ?-absorptions, the further ?-radiations etc. We must describe the ?-decay evolution, considering such excited states and multiple ?-radiations and ?-absorptions inside stars and also under the influence of the cosmic radiation on the earth surface. We present the quantum-mechanical approach, which is based on the generalized Krylov-Fock theorem. Some simple estimations are presented. They give rise to the conclusion that the usual (non-corrected) "nuclear clocks" do not really indicate the realistic values but the upper limits of the durations of the ?-decay stellar and planet processes.

Dolinska, M. E.; Doroshko, N. L.; Olkhovsky, V. S.

2014-06-01

351

Treatment of hyperthyroidism with radioactive iodine  

International Nuclear Information System (INIS)

While radioactive iodine is clearly the therapy of choice for Graves' disease (even in younger patients) the use of radioactive iodine for therapy of the toxic multinodular or uninodular goiter presents an entirely different problem. Although these two entities can be treated with radioactive iodine provided there is some suppression of the tissue that is not autonomous, transient release of thyroid hormone may induce symptoms of thyroid storm in the very large multinodular toxic goiter treated with radioiodine therapy. These toxic nodules generally require much larger doses of radioiodine than is commonly used for classical Graves' disease and may either require fractional administration of radioisotopes or concomitant use of antithyroid drugs and iodides. In general, surgery remains the treatment of choice for large toxic multinodular goiters, after proper preparation by medical means including radioactive iodine. Radioactive iodine therapy for hyperthyroidism is contraindicated in pregnancy and generally is not used in children below five years of age. (U.S.)

352

Mathematical problems in modeling artificial heart  

OpenAIRE

In this paper we discuss some problems arising in mathematical modeling of artificial hearts. The hydrodynamics of blood flow in an artificial heart chamber is governed by the Navier-Stokes equation, coupled with an equation of hyperbolic type subject to moving boundary conditions. The flow is induced by the motion of a diaphragm (membrane) inside the heart chamber attached to a part of the boundary and driven by a compressor (pusher plate). On one side of the diaphragm is the blood and on t...

Ahmed N. U.

1995-01-01

353

Dissociation of Vertical Semiconductor Diatomic Artificial Molecules  

International Nuclear Information System (INIS)

We investigate the dissociation of few-electron circular vertical semiconductor double quantum dot artificial molecules at 0T as a function of interdot distance. A slight mismatch introduced in the fabrication of the artificial molecules from nominally identical constituent quantum wells induces localization by offsetting the energy levels in the quantum dots by up to 2meV, and this plays a crucial role in the appearance of the addition energy spectra as a function of coupling strength particularly in the weak coupling limit

354

Artificial Coral Reefs  

Science.gov (United States)

Coral reefs are among the most diverse ecosystems on the planet...and the most threatened. Artificial reefs may help stem the loss of these valuable and beautiful habitats, with shipwrecks, old subway cars, and other structures taking the place of living coral or rocky outcrops. The following Web sites introduce artificial reefs, reef ecology, and some ongoing efforts to establish reef communities in the U.S. and beyond. PBS's NATURE offers a fascinating look at the artificial reefs created by the thousands of shipwrecks and downed planes from World War II that riddle the South Pacific (1). This is the companion Web site to the documentary War Wrecks of the Coral Seas, and it includes some great multimedia features. The next site comes from the National Oceanic and Atmospheric Administration and contains an excellent photo gallery of coral ecosystems around the world (2). The collection includes six pages of artificial reef photos taken in the Pacific. The following site comes from the online companion to the BBC's acclaimed documentary series The Blue Planet. Based on the episode The Web of Life, this site offers a fun, multimedia challenge for learning about and testing one's knowledge of coral reefs (3). The site includes a section on artificial reefs (click on Take it Further). Next, an August 2001 segment from National Public Radio's All Things Considered explores efforts to create artificial reefs using decommissioned New York City subway cars -- a project of Delaware's Department of Natural Resources and Environmental Control in the Division of Fish and Wildlife (4). Likewise, the non-profit group Artificial Reefs of the Keys is working to bring a de-commissioned military ship to the Florida Keys (5). The New Jersey Scuba Diver Web site provides an excellent introduction to artificial reef ecology; focused on reefs in New Jersey, of course. The mini-tutorial comes courtesy of William Figly, Principal Fisheries Biologist for the New Jersey Artificial Reef Program (6). The Fall 2001 issue of California Wild, the magazine of the California Academy of Sciences, addresses the benefits and concerns of off shore oil rigs becoming artificial reefs (7). Finally, visitors will find dozens of news articles and Web links related to artificial reefs in this entry, a page from the New England Artificial Reef Society Web site (8).

Sohmer, Rachel.

355

Six-year experiences in the environmental radioactivity monitoring in Taiwan  

International Nuclear Information System (INIS)

An islandwide network for environmental radioactivity monitoring established in 1974 is described with reference to (1) measurement of radioactive fallout from nuclear testings, (2) environmental monitoring for nuclear power plants and a radioactive waste disposal site, (3) a site specially designated by the government, and (4) installations involving radiation. Naturally occurring and artificial radionuclides are equally emphasized. All significant results are reported and discussed. (H.K.)

356

Natural radioactivity and human mitochondrial DNA mutations  

OpenAIRE

Radioactivity is known to induce tumors, chromosome lesions, and minisatellite length mutations, but its effects on the DNA sequence have not previously been studied. A coastal peninsula in Kerala (India) contains the world's highest level of natural radioactivity in a densely populated area, offering an opportunity to characterize radiation-associated DNA mutations. We sampled 248 pedigrees (988 individuals) in the high-radiation peninsula and in nearby low-radiation islands as a control pop...

Forster, Lucy; Forster, Peter; Lutz-bonengel, Sabine; Willkomm, Horst; Brinkmann, Bernd

2002-01-01

357

Experimental studies on utilization of argonless artificial air  

International Nuclear Information System (INIS)

The radioactive argon produced in nuclear reactors causes environmental pollution. One of the substantial methods to reduce radioactive argon is the utilization of the artificial air with low argon content in reactor rooms. The artificial air close to natural air is obtainable by mixing commercial oxygen and nitrogen, however, there are some technical problems to be solved before it is solved. A small scale facility supplying artificial air was manufactured for trial, in order to find the optimum condition of controlling the mixing and to develop the continuous measurement method for the argon concentration in artificial air. In this study, the following facts have been found. For providing with the argonless artificial air close to natural air, the mixing of the gases evaporating from commercial liquid oxygen and nitrogen can be safely controlled. For the mixing control covering the wide range of flow rate, it is necessary to set up an auxiliary line in low flow range, in addition to the ordinary main line. The method of controlling the flow ratio of oxygen and nitrogen is not suitable to the control in low flow range. The oxygen concentration control method detecting it continuously is applicable to the control of whole flow range. The argon concentration is measured with an X-ray emission spectrometer. (Kako, I.)

358

Radioactivity of wood ash  

International Nuclear Information System (INIS)

STUK (Finnish Radiation and Nuclear Safety Authority) has investigated natural and artificial radioactivity in wood ash and radiation exposure from radionuclides in ash since 1996. The aim was to consider both handling of ash and different ways of using ash. In all 87 ash samples were collected from 22 plants using entirely or partially wood for their energy production in 1996-1997. The sites studied represented mostly chemical forest industry, sawmills or district heat production. Most plants used fluidised bed combustion technique. Samples of both fly ash and bottom ash were studied. The activity concentrations of radionuclides in samples of, e.g., dried fly ash from fuel containing more than 80% wood were determined. The means ranged from 2000 to less than 50 Bq kg-1, in decreasing order: 137Cs, 40K, 90Sr, 210Pb,226Ra, 232Th, 134Cs, 235U. In bott radionuclide contents decreased in the same order as in fly ash, but were smaller, and 210Pb was hardly detectable. The NH4Ac extractable fractions of activities for isotopes of alkaline elements (K, Cs) in bottom ash were lower than in fly ash, whereas solubility of heavier isotopes was low. Safety requirements defined by STUK in ST-guide 12.2 for handling of peat ash were fulfilled at each of the sites. Use of ash for land-filling and construction of streets was minimal during the sampling period. Increasing this type of ash use had often needed further investigations, as description of the use of additional materials that attenuate radiation. Fertilisation of forests with wood ash adds slightly to the external irradiation in forests, but will mostly decrease doses received through use of timber, berries, mushrooms and game meat. (orig.)

359

Decrease of deposited artificial radioactivity in urban environments  

International Nuclear Information System (INIS)

The behavior of cesium during the first three years after deposition was investigated with in-situ gamma spectrometry at 48 measuring sites. An evaluation method was developed which allowed determination of retention on asphalt surfaces, the effective depth profile in soils covered with grass, and time factor developments of the gamma dose rate. Two months after deposition, the gamma dose rate on grassy soils amounts to 60% of the dose rate for smooth large-scale surfaces with identical deposition, but without weathering or soil migration. After 3 years this ratio lies at 35%. On asphalt surfaces, however, there was after 2 months only a dose rate of 20% of the dose rate on smooth surfaces without weathering; after 3 years it was only 4%. Environment factors were defined which determined the ratio of dose rates on measuring areas to dose rates on large grassy surfaces. The environment factors are the smaller, the bigger the proportion of asphalt. They are constant as regards the time factor, or they decrease gradually after deposition. Results were approximated analytically. The investigation of tiles showed that there was an activity retention of 30-60% on roofs in Munich following wet deposition of cesium. After 2 years it was still 10-25%. (orig./HP)

360

Very low levels of artificial radioactivity in 2008  

International Nuclear Information System (INIS)

A significant activity in cobalt 58 (2.8 milli becquerels / m3 in air) was measured in a sampling made on the site of the plant of Belleville-sur-Loire. At Pithiviers, a detection of uranium (22 micrograms by liter) was noticed in the water of the Essonne river. At Pierrelatte, release of uranium by the Socatri facility was observed in the water of the Gaffiere river no increase of the uranium concentration observed in underground waters. At Pierrelatte, release of carbon 14 in atmosphere by the Socatri facility, but the increase of efficient dose by ingestion of vegetables produced in this area did not exceed 0.2 micro sievert for a man. At Fleurus in Belgium, accidental release of iodine 131 but all the sampling were inferior to the limits of detection. (N.C.)

361

Artificial Sweeteners and Cancer  

Science.gov (United States)

... the safety of several artificial sweeteners, including saccharin, aspartame, acesulfame potassium, sucralose, neotame, and cyclamate. What are ... the warning label requirement for products containing saccharin. Aspartame Aspartame, distributed under several trade names (e.g., ...

362

Artificial intelligence in medicine.  

OpenAIRE

INTRODUCTION: Artificial intelligence is a branch of computer science capable of analysing complex medical data. Their potential to exploit meaningful relationship with in a data set can be used in the diagnosis, treatment and predicting outcome in many clinical scenarios. METHODS: Medline and internet searches were carried out using the keywords 'artificial intelligence' and 'neural networks (computer)'. Further references were obtained by cross-referencing from key articles. An overview of ...

Ramesh, A. N.; Kambhampati, C.; Monson, J. R. T.; Drew, P. J.

2004-01-01

363

Artificial Intelligence in Games  

OpenAIRE

Based on the recent surge in interest in the both academic and games industry in character- based artificial intelligence. Although the games are mainly related with entertainments, but with this there are other serious applications of gaming, including military training, educational games, driving training, medical training and games that reflect social consciousness or advocate for a cause. Artificial intelligence in games is a concept of taking game applications beyond the lim...

Raju; Nitin Sikka; Sanjeev Kumar; Rahul Gupta

2012-01-01

364

Light-driven artificial molecular machines  

Science.gov (United States)

Artificial molecular machines represent a growing field of nanoscience and nanotechnology. Stimulated by chemical reagents, electricity, or light, artificial molecular machines exhibit precisely controlled motion at the molecular level; with this ability molecular machines have the potential to make significant impacts in numerous engineering applications. Compared with molecular machines powered by chemical or electrical energy, light-driven molecular machines have several advantages: light can be switched much faster, work without producing chemical waste, and be used for dual purposes-inducing (writing) as well as detecting (reading) molecular motions. The following issues are significant for light-driven artificial molecular machines in the following aspects: their chemical structures, motion mechanisms, assembly and characterization on solid-state surfaces. Applications in different fields of nanotechnology such as molecular electronics, nano-electro-mechanical systems (NEMS), nanophotonics, and nanomedicine are envisaged.

Zheng, Yue Bing; Hao, Qingzhen; Yang, Ying-Wei; Kiraly, Brian; Chiang, I.-Kao; Huang, Tony Jun

2010-08-01

365

Radioactivity measurements as tool for physics dissemination  

International Nuclear Information System (INIS)

In general people associate environmental radioactivity with the artificial radioactivity and knows very little about natural radioactivity. Thus there is a critical need to improve nuclear physics public education. From 2005 in Italy two programs were promoted from Ministry of Education and University and National Institute of Nuclear Physics (INFN) for scientific dissemination in the field of environmental radioactivity. High school students in many Italian regions were involved in particular in indoor radon measurements. With this program students acquired awareness about the risks of inhalation of radon and its progeny and at the same time contributed to carry out radon monitoring, participating to all the experimental phases, from detectors set-up to data analysis. In particular we report about the activities carried out at Catania University and INFN division regarding a survey in the eastern Sicily. The overall monitoring, spanned over a period of 5 years, was carried out using passive nuclear track detection technique, through CR-39 dosimeters. In total about 500 detectors were placed in dwellings and schools in 57 locations. The investigated area have shown medium-high indoor radon concentrations, higher than the Italian average (70 Bq/m3). From the evaluation of the participating teachers and students, this kind of activities represents a successful strategy to enhance dissemination of physics, in particular in radioactivity topics. (author)

366

Generalised Derived Limits for Selected Artificial Radionuclides in Foodstruffs  

International Nuclear Information System (INIS)

The calculation of generalised derived limits for selected artificial radionuclides in foodstuffs consumed by the Indonesians have been carried out. The calculations is based on annual dose limit of 1 mSv for members of the public and the data on dose equivalent per unit of intake for the respective radionuclides, whilst the data of food consumption were taken from a survey conducted by The Central Bureau of Statistics. The generalised derived limits presented, as well as the derived investigation which the results of artificial radioactivity level monitoring in environmental foodstuffs can be compared. (author). 12 refs., 4 tabs

367

Pregnancy rate in lactating Bos indicus cows subjected to fixed-time artificial insemination and treated with different follicular growth inducers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The objective of this experiment was to evaluate the effects of replacing eCG with FSH or FSH/LH on the diameter of ovulatory follicles (DOF) and the pregnancy rates (PR) of lactating Bos indicus cows subjected to a synchronization of ovulation protocol and fixed-time artificial insemination (FTAI) [...] based on progesterone, estradiol benzoate (EB), PGF2?, and estradiol cypionate (EC). On day 0, primiparous and multiparous Nellore cows (n = 329) at 68 days postpartum were body condition scored (BCS) and received a P4 implant (PRIMER 1.0 g P4) plus 2 mg EB intramuscularly (IM). At day 8, the implant was removed, and 250 ?g cloprostenol were injected IM along with 0.5 mg EC. At the time of implant removal, the animals were divided into one of four treatments: cows received (G1) 1 mL of saline solution IM (Control; n = 80); (G2) 300 IU eCG IM (ECG300; n = 84); (G3) 15 mg FSH IM (Folltropin; n = 82); and (G4) 30 IU FSH/LH IM (Pluset; n = 83); all cows were subjected to FTAI 48-54 h after implant removal (day 10). Transrectal ultrasonography was performed to measure the DOF to FTAI and to estimate the pregnancy rate on day 35. A statistical analysis examined the effects of the treatment, technician, semen, BCS, calf age and parity on PR to FTAI. There was no significant difference in PR and DOF among the treatment groups (G1, 41.3%, 13.1 mm; G2, 46.4%, 14.5 mm; G3, 46.3%, 14.2 mm; and G4, 48.2%, 14.3 mm), but PR was higher in multiparous than in primiparous cows. Commercial FSH solutions (Pluset or Folltropin) do not promote increases in PR or DOF of lactating Nellore cows and are equal to eCG in promoting growth in preovulatory follicles and elevating the PR in Nellore cows with a moderate BCS subjected to a progesterone-based FTAI protocol with EC.

Ériklis, Nogueira; Dayanna Schiavi do Nascimento, Batista; Luiz Carlos Cesar da, Costa Filho; Alexandre Menezes, Dias; Juliana Corrêa Borges, Silva; Luís Carlos Vinhas, Ítavo.

2014-07-01

368

Ionizing radiations and radioactivity  

International Nuclear Information System (INIS)

This chapter explain the basic of ionizing radiations and its characteristic. Subtopics include radioactivity, quantity and unit, interaction with other materials, radioactive sources and its application in our daily life

369

Radioactivity in consumer products  

Energy Technology Data Exchange (ETDEWEB)

Papers presented at the conference dealt with regulations and standards; general and biological risks; radioluminous materials; mining, agricultural, and construction materials containing radioactivity; and various products containing radioactive sources.

Moghissi, A.A.; Paras, P.; Carter, M.W.; Barker, R.F. (eds.)

1978-08-01

370

Radioactivity and geophysics  

International Nuclear Information System (INIS)

The paper recalls a few steps of the introduction of radioactivity in geophysics and astrophysics: contribution of radioelements to energy balance of the Earth, age of the Earth based on radioactive disintegration and the discovery of cosmic radiations

371

Radioactive iodine uptake  

Science.gov (United States)

Iodine uptake test; RAIU ... to swallow a liquid or capsule containing radioactive iodine. After a certain period of time (usually 4 ... have: Diarrhea (may decrease absorption of the radioactive iodine) Had recent CT scans using intravenous or oral ...

372

Radioactive tracers in the sea  

International Nuclear Information System (INIS)

Artificial radionuclides introduced to the oceans during the last four decades have proved invaluable tools for study of many processes in marine water columns and sediments. Both global and close-in fallout of radioactivity from atmospheric nuclear weapons testing have distributed these radionuclides widely, and in amounts sufficient to be useful as tracers. An additional source of considerable significance and tracer potential comes from coastal discharges of European nuclear fuel reprocessing wastes. The nature of these sources, types and amounts of radionuclides introduced and the time histories of their introduction generate a variety of tracer distributions which illuminate a broad spectrum of physical and chemical processes active over a wide range of timescales. Depending on their respective chemistries, artificial radionuclides have been demonstrated to exhibit both conservative and non-conservative properties in the oceans. Some examples are given of the uses made of soluble, conservative tracers for the study of oceanic transport processes and of non-conservative tracers for studies of processes which move them to, and mix them within, marine sediments. Sampling and measurement techniques which have been used in these studies are described

373

Management of radioactive waste  

International Nuclear Information System (INIS)

The document gives an overview of of different aspects of radioactive waste management in Belgium. The document discusses the radioactive waste inventory in Belgium, the treatment and conditioning of radioactive waste as well as activities related to the characterisation of different waste forms. A separate chapter is dedicated to research and development regarding deep geological disposal of radioactive waste. In the Belgian waste management programme, particular emphasis is on studies for disposal in clay. Main results of these studies are highlighted and discussed

374

Radioactive waste management  

International Nuclear Information System (INIS)

This final part concerns the radioactive wastes management and includes: the commune convention on the safety of spent fuel management and on the safety of the radioactive wastes management, some remarks on the problem concerning the final disposal of high level and long lived radioactive wastes, lessons learned from the decommissioning of the Santo Amaro monazite processing plant: highlights of the Brazilian experience in sustained nuclear activities, the joint convention on the safety of radioactive waste management. (N.C.)

375

Understanding radioactive waste  

International Nuclear Information System (INIS)

This book discusses the sources and health effects of radioactive wastes. It reveals the techniques to concentrate and immobilize radioactivity and examines the merits of various disposal ideas. The book, which is designed for the lay reader, explains the basic science of atoms,nuclear particles,radioactivity, radiation and health effects

376

Production of radioactive stents  

International Nuclear Information System (INIS)

In the last years radioactive stents proved to inhibit neointima formation. This report describes the actual status of producing such radioactive stents. Different methods of radioactive Stent production are considered. The ion beam implantation of P-32 applied at the Research Center Karlsruhe will be described in more detail. (orig.)

377

Artificial Intelligence in Games  

Directory of Open Access Journals (Sweden)

Full Text Available Based on the recent surge in interest in the both academic and games industry in character- based artificial intelligence. Although the games are mainly related with entertainments, but with this there are other serious applications of gaming, including military training, educational games, driving training, medical training and games that reflect social consciousness or advocate for a cause. Artificial intelligence in games is a concept of taking game applications beyond the limits of interactive gaming. Such system learn about the player’s behaviours during game play and beyond the pre-programmed set provides and interactively develop and provide a best experience to the players.General Terms The main aim of our research is to develop such artificial intelligence techniques that can have a substantial impact in the game industry. In the following research paper we are going to study about Case Based Reasoning (CBR, automatic behaviour adjustment for believing characters, drama management and user modelling for interactive stories and strategic behaviour planning for real time strategy games. We include problems in adopting artificial intelligence in games and some algorithms for respective games. Future aspect of artificial intelligence in games is also mentioned in the paper.

Raju

2012-11-01

378

Artificial Heart Design Challenge  

Science.gov (United States)

Students are presented with a hypothetical scenario in which they are biomedical engineers asked to design artificial hearts. Using the engineering design process as a guide, the challenge is established and students brainstorm to list everything they might need to know about the heart in order to create a complete mechanical replacement (size, how it functions, path of blood etc.). They conduct research to learn the information and organize it through various activities. They research artificial heart models that have already been used and rate their performance in clinical trials. Finally, they analyze the data to identify the artificial heart features and properties they think work best and document their findings in essay form.

Bio-Inspired Technology and Systems (BITS) RET,

379

Artificial intelligence executive summary  

International Nuclear Information System (INIS)

Artificial intelligence (AI) is a high technology field that can be used to provide problem solving diagnosis, guidance and for support resolution of problems. It is not a stand alone discipline, but can also be applied to develop data bases for retention of the expertise that is required for its own knowledge base. This provides a way to retain knowledge that otherwise may be lost. Artificial Intelligence Methodology can provide an automated construction management decision support system, thereby restoring the manager's emphasis to project management

380

Air conditioner for radioactive material handling facility  

International Nuclear Information System (INIS)

An air conditioner intakes open-air from an open-air intake port to remove sands and sea salt particles by air filters. Then, natural and artificial radioactive particles of less than 1 ?m are removed by high performance particulate filters. After controlling the temperature by an air heater or an air cooler, air is sent to each of chambers in a facility under pressure elevation by a blower. In this case, glass fibers are used as the filter material for the high performance particulate filter, which has a performance of more than 99.97% for the particles of 0.3 ?m grain size. Since this can sufficiently remove the natural radioactive materials intruded from the outside, a detection limit value in each of the chambers of the facility can be set 10-13 to 10-14 ?ci/cm3 in respect of radiation control. Accordingly, radiation control can be conducted smoothly and appropriately. (I.N.)

381

Potentiated clinoptilolite: artificially enhanced aluminosilicate reduces symptoms associated with endoscopically negative gastroesophageal reflux disease and nonsteroidal anti-inflammatory drug induced gastritis  

Directory of Open Access Journals (Sweden)

Full Text Available Wilna Potgieter, Caroline Selma Samuels, Jacques Renè SnymanDepartment of Pharmacology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, Gauteng, South AfricaPurpose: The cation exchanger, a potentiated clinoptilolite (Absorbatox™ 2.4D, is a synthetically enhanced aluminosilicate. The aim of this study was to evaluate the possible benefits of a potentiated clinoptilolite as a gastroprotective agent in reducing the severity of clinical symptoms and signs associated with 1 endoscopically negative gastroesophageal reflux disease (ENGORD and 2 nonsteroidal anti-inflammatory drug (NSAID medication.Methods and patients: Two randomized, double-blind, placebo-controlled, pilot studies, the ENGORD and NSAID studies, were conducted. After initial negative gastroscopy, a total of 25 patients suffering from ENGORD were randomized to receive either placebo capsules or 750 mg Absorbatox twice daily for 14 days. The NSAID study recruited 23 healthy patients who received orally either 1,500 mg Absorbatox or placebo three times daily, plus 500 mg naproxen twice daily. Patients underwent gastroscopic evaluation of their stomach linings prior to and on day 14 of the study. Gastric biopsies were obtained and evaluated via the upgraded Sydney system, whereas visible gastric events and status of the gastric mucosa were evaluated via a 0–3 rating scale. During both studies, patients recorded gastric symptoms in a daily symptom diary.Results: In the ENGORD study, patients who received the potentiated clinoptilolite reported a significant reduction (P?0.05 in severity of symptoms including reduction in heartburn (44%, discomfort (54%, and pain (56%. Symptom-free days improved by 41% compared to the group who received placebo (not significant. This was over and above the benefits seen with the proton pump inhibitor. In the NSAID study, the reduction in gastric symptom severity was echoed in the group who received the potentiated clinoptilolite. Treatment with the potentiated clinoptilolite resulted in significant prevention (P?0.05 of mucosal erosion severity as graded by the gastroenterologist.Conclusion: Absorbatox is a nonabsorbable aluminosilicate with potential gastroprotective benefits as it protected against ENGORD symptoms and NSAID-induced gastric events. The exact mechanism of action is not clear but may be due to its binding to hydrogen ions and biologically active amines and nitrates.Keywords: cation exchanger, gastro-protective agent, endoscopy, zeolite

Potgieter W

2014-07-01

382

Regions with increased natural radioactivity. Pt. 3  

International Nuclear Information System (INIS)

The goals pursued by the investigation on hand were: 1. to get a survey of natural radioactivity in the Fichtelgebirge; 2. to find and describe locally restricted areas of high natural radioactivity (abnormal radiation, hot spots); this will be a starting point 3. for the assessment of possible increased radiation exposure and of the state of health of a restricted number of persons. Furthermore, there are also 4. underground data for the eventual stipulation of maximum permissible values for natural radioactivity. 5. The situation in the Fichtelgebirge shall be compared with that of the monazite sand-stone areas in India. The highest gamma dose rates measured in locally restricted areas were: 1. granite road pavement: 24 ?R/h; 2. granite quarries (35 ?R/h); 3. caves below granite rock (40 to 70 ?R/h); 4. slag brick pavement on market place and main street of Marktredwitz (53.4 ?R/h) (part of which removed already); 5. uranium abnormalities on a farmer's field (80-100 ?R/h) (0.6 m below the surface: 1.500 ?R/h); this may be considered an uranium deposit with a content in uranium of up to 0.3%; 6. over 100 ?R/h in front of an uranium ore mine in the uranium prospection drift (rest of the drift in the granite no more than 29.3+-3.3 ?R/h). The resulting maximum conceivable radiation exposure is assessed. The question whether there is a necessity for setting tolerance limit values for natural radioactivity is raised again; the magnitude in comparison with limit values for artificial radioactivity in radioactive controlled areas is pointed out. (orig./HP)

383

Survey monitoring of environmental radioactivity in Daegu area  

Energy Technology Data Exchange (ETDEWEB)

The objectives of the project are to monitor an abnormal radiation level in Taegu and Kyungpook region, and to enhance our ability to prepare for the radiological emergency situation by establishing the radioactivity monitoring system in Taegu and Kyungpook region. Gross beta activities were measured and gamma radionuclides were analysed for the environmental samples of air-borned dust. precipitation. fallout and drinking water collected in Taegu radioactivity monitoring center. and gamma exposure rates were also measured. To establish the basic data base on the environmental radioactivity, gamma radionuclide analyses were carried out for the samples of soil, drinking water, grain, vegetable, milk, and fish which were obtained from 31 different areas, and the spatial gamma exposure rates from 61 different points were also measured in Taegu and Kyungpook region. In conclusion, it didn't appear any evidence for newly pollution of artificial radioactivity in Taegu and Kyungpook region.

Kang, H. D.; Lee, S. Y. [Kyungpook National Univ., Daegu (Korea, Republic of)

1998-01-15

384

Measurement of environmental radioactivity in Toki district  

International Nuclear Information System (INIS)

When the Institute of Plasma Physics, Nagoya University, expressed the hope to move into Toki district, the environmental problems accompanying the movement were discussed. The effect of the radioactivity leaking from the nuclear facility on human bodies must be far smaller than that of natural radiation, and for the purpose, the amount and fluctuation range of the natural radiation in the district must be known. The initial objectives of this cooperative research were to study on environmental radiation and to make a Geiger counter for the measurement. In 1981, a scintillation counter will be completed, and using a multi-channel pulse height analyzer, the nuclides which are the source of environmental radiation emission will be identified, and the tritium in natural water will be detected. Thus, the evaluation of environmental radiation can be carried out, and the situation before the movement of the research facility can be grasped. In this paper, the natural radioactivity in earth, atmosphere and water and cosmic ray, artificial radioactivity, and environmental radiation exposure dose are reported. Also, the manufacture of a GM counter measuring instrument and the measurements of cosmic ray background, typical earth samples and environmental radioactivity with the GM counter are reported. The related data are attached. (Kako, I.)

385

Artificial intelligence and robotics  

Energy Technology Data Exchange (ETDEWEB)

This report examines the state-of-the-art in artificial intelligence and robotics technologies and their potential in terms of Army needs. Assessment includes battlefield technology, research and technology insertions, management considerations and recommendations related to research and development personnel, and recommendations regarding the Army's involvement in the automated plant.

Peden, I.C.; Braddock, J.V.; Brown, W.; Langendorf, R.M.

1982-09-01

386

Argumentation in Artificial Intelligence  

CERN Document Server

Examines the intersection between two fields of inquiry, including Argumentation Theory and Artificial Intelligence. This book presents an overview of key concepts in argumentation theory and of formal models of argumentation in AI. It offers a review of the foundational issues in argumentation and formal argument modeling.

Simari, Guillermo

2009-01-01

387

Artificial Hydration and Nutrition  

Science.gov (United States)

... than by mouth. This is referred to as artificial hydration and nutrition. This is sometimes done when someone is recovering from a temporary problem, such as when fluids have been lost through vomiting, sweating, or diarrhea. It may also be done when ...

388

Artificial recharge of groundwater  

Science.gov (United States)

The Task Committee on Guidelines for Artificial Recharge of Groundwater, of the American Society of Civil Engineers' (ASCE) Irrigation and Drainage Division, sponsored an International Symposium on Artificial Recharge of Groundwater at the Inn-at-the-Park Hotel in Anaheim, Calif., August 23-27, 1988. Cosponsors were the U.S. Geological Survey, California Department of Water Resources, University of California Water Resources Center, Metropolitan Water District of Southern California, with cooperation from the U.S. Bureau of Reclamation, International Association of Hydrological Sciences, American Water Resources Association, U.S. Agency for International Development, World Bank, United Nations Department of Technical Cooperation for Development, and a number of local and state organizations.Because of the worldwide interest in artificial recharge and the need to develop efficient recharge facilities, the Anaheim symposium brought together an interdisciplinary group of engineers and scientists to provide a forum for many professional disciplines to exchange experiences and findings related to various types of artificial recharge; learn from both successful and unsuccessful case histories; promote technology transfer between the various disciplines; provide an education resource for communication with those who are not water scientists, such as planners, lawyers, regulators, and the public in general; and indicate directions by which cities or other entities can save funds by having reasonable technical guidelines for implementation of a recharge project.

389

Artificial intelligence and automation  

CERN Document Server

Covering artificial intelligence and automation, these contributions discuss: the evolution of AI tools; an SPN knowledge representation scheme; software engineering using AI; the impact of AI in VLSI design automation; incremental adaptation as a method to improve reactive behaviour; and more.

Bourbakis, NG

1998-01-01

390

Artificial binary data scenarios  

OpenAIRE

This manual describes artificial binary data scenarios. These data sets can be used to compare the performance of algorithms for market segmentation. The data sets described in this manual are available as packages for R (Splus) and as ASCII-files under htttp://www.ci.tuwien.ac.at/SFB/. (author's abstract)

Dolnicar, Sara; Leisch, Friedrich; Weingessel, Andreas

1998-01-01

391

Artificial Left Ventricle  

CERN Document Server

This Artificial left ventricle is based on a simple conic assumption shape for left ventricle where its motion is made by attached compressed elastic tubes to its walls which are regarded to electrical points at each nodal .This compressed tubes are playing the role of myofibers in the myocardium of the left ventricle. These elastic tubes have helical shapes and are transacting on these helical bands dynamically. At this invention we give an algorithm of this artificial left ventricle construction that of course the effect of the blood flow in LV is observed with making beneficiary used of sensors to obtain this effecting, something like to lifegates problem. The main problem is to evaluate powers that are interacted between elastic body (left ventricle) and fluid (blood). The main goal of this invention is to show that artificial heart is not just a pump, but mechanical modeling of LV wall and its interaction with blood in it (blood movement modeling) can introduce an artificial heart closed to natural heart...

Ranjbar, Saeed; Meybodi, Mahmood Emami

2014-01-01

392

Radioactive dust sampling  

International Nuclear Information System (INIS)

This technical report is the second of a five part series on the technical evaluation of a number of dust monitoring instruments and the characterization of Long-Lived Radioactive Dust (LLRD). The data reported here pertain to an experimental study conducted under laboratory controlled conditions in a Long-Lived Radioactive Dust Test Facility (LLRDTF) designed for this purpose. This study was carried out with a twofold purpose in mind, namely, for the characterization of dust and LLRD, and for the evaluation of a variety of monitoring instruments, including cascade impactors, optical particle counters, nylon cyclones, open face filter samplers, and ?-particle personal dosimeters, the latter normally used for ?-particle radiation exposure purposes. Several non-radioactive and radioactive dusts were characterized. The non-radioactive dusts were SiC, Al2O3, talcum powder, corn starch and flour, while uranium tailings were used as a radioactive dust. Clear differences in instrument performance were observed for the various measurements made

393

Terrestrial radioactivity monitoring programme (TRAMP) report for 1993. Radioactivity in food and agricultural products in England and Wales  

International Nuclear Information System (INIS)

This Eighth Annual Report of the Terrestrial Radioactivity Monitoring Programme (TRAMP) describes the results of analyses performed on food and agricultural products from England and Wales to determine levels of radioactive contamination present for the year 1993. The monitoring programme run by the Ministry of Agriculture, Fisheries and Food, aims to ensure that legal or recommended radiation limits are not exceeded. TRAMP is run alongside a complementary monitoring programme (the Food and Agriculture Monitoring Programme or FARM) to ensure reliability of results. TRAMP concentrates on crops produced near the twenty three nuclear sites, whereas FARM focuses on the safety of the general food supply, nationally. The report finds that assessed doses mean that public exposure to artificial radioactivity due to consumption of foodstuffs was well within acceptable limits and suggests that this confirms the adequacy of existing controls set on the disposal of radioactive wastes. (UK)

394

Learning more about radioactivity  

International Nuclear Information System (INIS)

This digest brochure explains what radioactivity is, where it comes from, how it is measured, what are its effects on the body and the way to protect it against these effects, the uses of radioactivity (In the medical field, In industry, In the food industry, and In the cultural world). It ends with some examples of irradiation levels, of natural radioactivity and with the distribution in France of various sources of exposure. (J.S.)

395

Drainage of radioactive areas  

International Nuclear Information System (INIS)

This Code of Practice covers all the drainage systems which may occur in the radioactive classified area of an establishment, namely surface water, foul, process and radioactive drainage. It also deals with final discharge lines. The Code of Practice concentrates on those aspects of drainage which require particular attention because the systems are in or from radioactive areas and typical illustrations are given in appendices. The Code makes references to sources of information on conventional aspects of drainage design. (author)

396

Radioactivity and its measurement  

CERN Document Server

Begins with a description of the discovery of radioactivity and the historic research of such pioneers as the Curies and Rutherford. After a discussion of the interactions of &agr;, &bgr; and &ggr; rays with matter, the energetics of the different modes of nuclear disintegration are considered in relation to the Einstein mass-energy relationship as applied to radioactive transformations. Radiation detectors and radioactivity measurements are also discussed

Mann, W B; Garfinkel, S B

1980-01-01

397

Application of artificial intelligence to radiation control, (1)  

International Nuclear Information System (INIS)

Recently artificial intelligence (AI) which has functions of our interpretations and judgments has been applied to various fields of science. In the first application of AI to the transport procedure of the radioactive material, a prototype of expert system was developed with UTI-LISP programming language to appropriately classify mainly the packages and packagings according to regulations for the safe transport of radioactive material. Classification of the packages and packagings for the consignment is mainly determined from input informations such as radionuclides, its activities, states and conveyances through a forward reasoning method of the expert system. The rationalization of practice on our interpretations and judgments for transport of radioactive material including uniformity and reliability of our decision were confirmed as the result of an application to radiation control. (author)

398

Radioactive waste management  

International Nuclear Information System (INIS)

Radioactive waste management involves two fundamental approaches: the radioactive materials can be either released or discharged to the environment, or they must be confined and isolated from the biosphere until the noxious radionuclides have decayed to innocuous concentrations. Releases of radioactivity to the environment generally occur as liquid or gaseous discharges (effluents) from nuclear facilities. The amount of radioactivity which can be released is based on allowable exposures to population groups and is controlled by national regulations and guidelines, usually based on recommendations of the International Committee on Radiation Protection. There are very few instances where radioactive effluents from nuclear facilities can be released without some form of control or treatment to remove excessive radioactivity. Most of the radioactive wastes arising from the operation of nuclear fuel cycle facilities require processing to concentrate the radioactive elements into a smaller volume which can be more conveniently handled, thereby permitting the release or disposal of the bulk of the processed material. Radioactive waste management involves the use of normal industrial operations and techniques adapted to cope with the barriers needed to protect the workers and operations from excessive radiation and contact with the radionuclides. Consequently, very often the equipment and its operating procedures become rather sophisticated to permit operation and maintenanceicated to permit operation and maintenance behind the protective barriers. Actually, most research and development activities involving technology for the management of radioactive wastes are concerned with adapting normal industrial operations or laboratory techniques to the handling of radioactive materials. It is the consensus amongst those involved with, or knowledgeable about, radioactive waste management, that technology and flow schemes have now been developed to the extent that they are workable. The basic knowledge required to collect, treat, package and store safely all nuclear fuel cycle wastes of concern is available. Furthermore, in many cases, optional technology exists for different situations or economic optimization. Consequently, from a technical standpoint, it seems that lack of appropriate methods and technology for handling the radioactive waste need not become a bottleneck for the implementation of nuclear power. On the other hand, some of the required radioactive waste management technology still remains in its developmental stage. Much remains to be done in working out the engineering and design details, satisfying appropriate regulatory requirements, and adapting the technology to actual operating conditions and controls. These last remarks apply principally to those radioactive wastes arising from the reprocessing of irradiated fuel which essentially contain all the radioactive products of nuclear fission

399

Radioactive waste in perspective  

CERN Document Server

Large volumes of hazardous wastes are produced each year, however only a small proportion of them are radioactive. While disposal options for hazardous wastes are generally well established, some types of hazardous waste face issues similar to those for radioactive waste and also require long-term disposal arrangements. The objective of this NEA study is to put the management of radioactive waste into perspective, firstly by contrasting features of radioactive and hazardous wastes, together with their management policies and strategies, and secondly by examining the specific case of the wastes

2010-01-01

400

Controlling radioactive waste  

International Nuclear Information System (INIS)

The guideline of the Ministry for Environmental Protection for controlling radioactive waste with a negligible development of heat defines in detail what data are relevant to the control of radioactive waste and should be followed up on and included in a system of documentation. By introducing the AVK (product control system for tracing the course of waste disposal) the operators of German nuclear power plants have taken the requirements of this guideline into account. In particular, possibilities for determining the degree of radioactivity of radioactive waste, which the BMU-guidelines call for, were put into practice by means of the programming technology of the product control system's module MOPRO. (orig.)

401

Radioactive Waste Management Basis  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this Radioactive Waste Management Basis is to describe the systematic approach for planning, executing, and evaluating the management of radioactive waste at LLNL. The implementation of this document will ensure that waste management activities at LLNL are conducted in compliance with the requirements of DOE Order 435.1, Radioactive Waste Management, and the Implementation Guide for DOE Manual 435.1-1, Radioactive Waste Management Manual. Technical justification is provided where methods for meeting the requirements of DOE Order 435.1 deviate from the DOE Manual 435.1-1 and Implementation Guide.

Perkins, B K

2009-06-03

402

Thermal fluctuations in artificial spin ice  

Science.gov (United States)

Artificial spin ice systems have been proposed as a playground for the study of monopole-like magnetic excitations, similar to those observed in pyrochlore spin ice materials. Currents of magnetic monopole excitations have been observed, demonstrating the possibility for the realization of magnetic-charge-based circuitry. Artificial spin ice systems that support thermal fluctuations can serve as an ideal setting for observing dynamical effects such as monopole propagation and as a potential medium for magnetricity investigations. Here, we report on the transition from a frozen to a dynamic state in artificial spin ice with a square lattice. Magnetic imaging is used to determine the magnetic state of the islands in thermal equilibrium. The temperature-induced onset of magnetic fluctuations and excitation populations are shown to depend on the lattice spacing and related interaction strength between islands. The excitations are described by Boltzmann distributions with their factors in the frozen state relating to the blocking temperatures of the array. Our results provide insight into the design of thermal artificial spin ice arrays where the magnetic charge density and response to external fields can be studied in thermal equilibrium.

Kapaklis, Vassilios; Arnalds, Unnar B.; Farhan, Alan; Chopdekar, Rajesh V.; Balan, Ana; Scholl, Andreas; Heyderman, Laura J.; Hjörvarsson, Björgvin

2014-07-01

403

The radioactive inventory of a decommissioned magnox power station structure. 1. Measurements of neutron induced activity in samples from the reactor island  

International Nuclear Information System (INIS)

This report is the first of a series which, together, aim to produce an accurate assessment of neutron induced activation levels in the fixed structural components of a reactor of the steel pressure vessel Magnox type. It describes the measurements made of induced activation, necessary in order to establish credibility in the complex calculations described in the subsequent reports. The report also attempts systematically to assess the potential contributions to the dose and disposal problem from all isotopes with a half-life in excess of 5 years. This is necessary in order to ensure that no isotope has been overlooked which could limit any part of the plan for the decommissioning of a Magnox reactor. In addition the report aims to determine concentrations, in each major material type, of trace elements which lead to the isotopes limiting in decommissioning. (author)

404

Stress and radioactive waste management  

International Nuclear Information System (INIS)

In the Supreme Court case ''People Against Nuclear Energy (PANE) vs Metropolitan Edison,'' one of the conclusions was that the Nuclear Regulatory Commission did not have to consider psychological distress, community cohesiveness and sense of well-being in the supplement to the Environmental Impact Statement (EIS) covering the restart of Three Mile Island (TMI). This decision was based on the assumption that the intention of the National Environmental Policy Act (NEPA) is to focus on the physical environment, and the casual chain between psychological distress and adverse health effects is tenuous. In this paper the authors summarize the literature on the relationship between environmentally-induced stress and its effects on health. They present the results of a new survey research project in which levels of stress were evaluated in West Chicago, Illinois, a community in which radioactive wastes have been present for many years. Explanatory social variables are brought into the evaluation in which stress is evaluated as a function of proximity to the radioactive waste site. In addition, stress is discussed in the context of attitudes on nuclear power, environmental group participation, and knowledge about the health effects associated with radioactive waste. The paper ends with a discussion of the portion of the Supreme Court decision in which psychological distress, community stability, cohesiveness and sense of well being are excluded as variables to address in EISs excluded as variables to address in EISs

405

Estimation of radioactive concentration limit for trench disposal of transuranium and uranium wastes (Contract research)  

International Nuclear Information System (INIS)

Spent nuclear fuel reprocessing and MOX fuel manufacturing generate radioactive wastes rich in transuranic nuclides (transuranium waste). Uranium enrichment and fuel manufacturing generate radioactive wastes composed mainly of uranium isotopes and their daughter nuclides (uranium waste). The Atomic Energy Commission of Japan states that the transuranium waste and uranium waste are to be disposed of by either near surface disposal without artificial barrier (trench disposal), near surface disposal with artificial barrier (concrete vault disposal), or intermediate depth disposal, depending on the radionuclides and their radioactivity concentrations in the wastes. The ranges of radioactivity concentration for these different disposal concepts are, therefore, required to be determined for the regulation. The radioactivity concentration limits define the upper bound of radioactivity concentrations for licensing application of the disposal of radioactive waste. This document summaries the concept and method (scenario selection, model/code description and parameter selection) for estimation of the radioactivity concentration limits for trench disposal of transuranium and uranium wastes, and provides the derived values of the radioactivity concentration limit for each radionuclide in the wastes. The values for the transuranium waste have been published in a Nuclear Safety Commission of Japan report. (author)

406

Environmental radioactivity in Turkey, 2007  

International Nuclear Information System (INIS)

In this report, the activity concentrations of natural and artificial radionuclides, gross alpha/beta activities and air gamma dose rates in the environmental and food samples provided from Turkey's seven geographical regions within the environmental radioactivity monitoring program in 2007 are presented. The activity concentrations of the natural (238U, 232Th, 226Ra, 4:0K and 7Be) and artificial (137Cs, 134Cs, 90Sr, 238-239+240Pu, 241Am) radionuclides and gross alpha/beta activities in the samples were measured by using the gamma spectrometry, the alpha spectrometry, the liquid scintillation counter and the gross alpha /beta counting system. Results show that 137Cs and 90Sr radionuclides originating from the Chernobyl Nuclear Reactor accident in 1986 exist in some of samples even in low levels. The mean activity concentrations of 238U, 232Th, 226Ra and 40K in the studied surface soil samples were found as 32.1 Bq kg-1, 35.0 Bq kg-1, 29.0 Bq kg-1 and 446.7 Bq kg-1, respectively, while the mean activity concentrations of the fission product 137Cs was found as 18.4 Bq kg-1. While the activity concentrations of 238U, 232Th and 226Ra in the analyzed food samples are lower than the minimum detectable activity (MDA), 134Cs and 7Be radionuclides are not observed. The mean activity concentrations of 137Cs and 90Sr radionuclides are 0.24 Bq L-1 and 0.05 Bq L-1, respectively. (Includes 4 tables and 7 figures)

407

Gross alpha radioactivity of drinking water in Venezuela  

International Nuclear Information System (INIS)

Bottled mineral water is consumed by a large population in Venezuela. The alpha emitters concentration was measured in samples of bottled water and water springs collected near the surface. Approximately 30% of the total mineral water suppliers was monitored. a database on natural and artificial radioactivity in drinking water was produced. Results indicate that 54% of the waters sampled contain a total alpha radioactivity of less than 0.185 Bql-1 and only 12% above 0.37 Bql-1. Our results revealed a total annual dose of 2.3 mSv year-1. (author)

408

Evaluation of Terrorist Interest in Radioactive Wastes  

International Nuclear Information System (INIS)

Since September 11, 2001, intelligence gathered from Al Qaeda training camps in Afghanistan, and the ensuing terrorist activities, indicates nuclear material security concerns are valid. This paper reviews available information on sealed radioactive sources thought to be of interest to terrorists, and then examines typical wastes generated during environmental management activities to compare their comparative 'attractiveness' for terrorist diversion. Sealed radioactive sources have been evaluated in numerous studies to assess their security and attractiveness for use as a terrorist weapon. The studies conclude that tens of thousands of curies in sealed radioactive sources are available for potential use in a terrorist attack. This risk is mitigated by international efforts to find lost and abandoned sources and bring them under adequate security. However, radioactive waste has not received the same level of scrutiny to ensure security. This paper summarizes the activity and nature of radioactive sources potentially available to international terrorists. The paper then estimates radiation doses from use of radioactive sources as well as typical environmental restoration or decontamination and decommissioning wastes in a radioactive dispersal device (RDD) attack. These calculated doses indicate that radioactive wastes are, as expected, much less of a health risk than radioactive sources. The difference in radiation doses from wastes used in an RDD are four to nine ordeastes used in an RDD are four to nine orders of magnitude less than from sealed sources. We then review the International Atomic Energy Agency (IAEA) definition of 'dangerous source' in an adjusted comparison to common radioactive waste shipments generated in environmental management activities. The highest waste dispersion was found to meet only category 1-3.2 of the five step IAEA scale. A category '3' source by the IAEA standard 'is extremely unlikely, to cause injury to a person in the immediate vicinity'. The obvious conclusion of the analysis is that environmental management generated radioactive wastes have substantially less impact than radioactive sources if dispersed by terrorist-induced explosion or fire. From a health standpoint, the impact is very small. However, there is no basis to conclude that wastes are totally unattractive for use in a disruptive or economic damage event. Waste managers should be cognizant of this potential and take measures to ensure security of stored waste and waste shipments. (authors)

409

Environmental radioactivity in Turkey, 2010  

International Nuclear Information System (INIS)

In this report, the activity concentrations of natural and artificial radionuclides and gross alpha/beta activities measured in the environmental and food samples provided from 81 provinces of the country within the environmental radioactivity monitoring program in 2010 and outdoor gamma dose rates obtained by means of car-borne measurement system are presented. The activity concentrations of the natural and artificial radionuclides in the samples were measured by using the gamma spectrometry, the alpha spectrometry, the liquid scintillation counter and the gross alpha /beta counting system. The mean activity concentrations of 226Ra, 232Th and 40K in the analyzed surface samples were found as 28.11±1.23 Bq kg-1, 32.4±1.2 Bq kg-1 and 430.8±12.5, respectively, while the mean activity concentration of the fission product 137Cs was found as 9.78±0.79 Bq kg-1. The mean absorbed gamma dose rate in outdoor due to external exposure emitted by natural radionuclides in soil samples and the corresponding annual effective dose were evaluated as 50.5 nGy h-1 and 0.062 mSv y-1, respectively. Total indicative doses of the analyzed drinking water samples were below the limit values. The activity concentrations of 238U, 232Th and 226Ra in the analyzed food samples were lower than the minimum detectable activity while 134Cs radionuclide was not observed. The mean activity concentrations of 137Cs and 90Sr radionuclides measured in the milk samples are 1.01 Bq L-1 and 0.29 Bq L-1, respectively. These values are lower than the limit value specified for foods subjected to control based on the regulation of the EU 737/90/EC. The total annual effective dose arising from the internal exposure from radiation emitting from 40K, 137Cs and 90Sr radionuclides analyzed in the food samples are evaluated as 196.6 Sv. In conclusion, the results of the monitoring program in 2010 show that the levels of radioactivity in the environment are low and do not pose any significant risk to human health and the environment.

410

Fission and activation product data relevant to the studies on radioactive fallout from atmospheric nuclear explosions  

International Nuclear Information System (INIS)

An attempt has been made to summarize the available information about the various aspects of radioactive fallout from atmospheric nuclear explosions. This includes data on the various fission products and other radioactive isotopes produced in nuclear explosions, fission yields, production ratios, induced radioactivities, etc. (K.B.)

411

Spatially Resolved Artificial Chemistry  

DEFF Research Database (Denmark)

Although spatial structures can play a crucial role in chemical systems and can drastically alter the outcome of reactions, the traditional framework of artificial chemistry is a well-stirred tank reactor with no spatial representation in mind. Advanced method development in physical chemistry has made a class of models accessible to the realms of artificial chemistry that represent reacting molecules in a coarse-grained fashion in continuous space. This chapter introduces the mathematical models of Brownian dynamics (BD) and dissipative particle dynamics (DPD) for molecular motion and reaction. It reviews calibration procedures, outlines the computational algorithms, and summarizes examplary applications. Four different platforms for BD and DPD simulations are presented that differ in their focus, features, and complexity.

Fellermann, Harold

2009-01-01

412

Transport of radioactive materials  

International Nuclear Information System (INIS)

The NRPB present a fold-out leaflet in the At-a-glance series, concerning the transport of radioactive materials. Intended for the transport industry, the leaflet's contents cover the uses of radioactive materials, types of packages and containers, modes of transport, routine doses, and accidents. (UK)

413

Classification of radioactive waste  

International Nuclear Information System (INIS)

The objective of this safety guide is to recommend a general system for classifying radioactive waste to facilitate communication among all concerned. Both qualitative and quantitative aspects are covered in this safety guide for classification of radioactive waste to determine their safe management

414

A Remote Radioactivity Experiment  

Science.gov (United States)

Imagine a high school with very few experimental resources and limited budgets that prevent the purchase of even basic laboratory equipment. For example, many high schools do not have the means of experimentally studying radioactivity because they lack Geiger counters and/or good radioactive sources. This was the case at the first high school one…

Jona, Kemi; Vondracek, Mark

2013-01-01

415

Radioactive fallout in Kuwait  

International Nuclear Information System (INIS)

A sampling station for radioactive fallout established by the Radiation Protection Division, Ministry of Public Health has been in operation since December 1978. Samples are collected weekly, processed to dry residue and the radioactivity measured using low level background equipment. The paper gives the results of fallout measurements in Kuwait. (author)

416

Radioactive waste disposal package  

Science.gov (United States)

A radioactive waste disposal package comprising a canister for containing vitrified radioactive waste material and a sealed outer shell encapsulating the canister. A solid block of filler material is supported in said shell and convertible into a liquid state for flow into the space between the canister and outer shell and subsequently hardened to form a solid, impervious layer occupying such space.

Lampe, Robert F. (Bethel Park, PA)

1986-01-01

417

Radioactive krypton gas separation  

International Nuclear Information System (INIS)

Radioactive krypton is separated from a gas mixture comprising nitrogen and traces of carbon dioxide and radioactive krypton by selective adsorption and then cryogenic distillation of the prepurified gas against nitrogen liquid to produce krypton bottoms concentrate liquid, using the nitrogen gas from the distillation for two step purging of the adsorbent. 16 Claims, 8 Drawing Figures

418

The natural atmospheric radioactivity  

International Nuclear Information System (INIS)

The paper deals with the natural sources and concentrations of different radioactive isotopes found in the atmosphere. Based on the results of Hungarian observatories illustrative data of the atmospheric radioactivity, characteristic of seasonal and directional distributions are given. (Sz.J.)

419

Sealed radioactive sources toolkit  

International Nuclear Information System (INIS)

The IAEA has developed a Sealed Radioactive Sources Toolkit to provide information to key groups about the safety and security of sealed radioactive sources. The key groups addressed are officials in government agencies, medical users, industrial users and the scrap metal industry. The general public may also benefit from an understanding of the fundamentals of radiation safety

420

Artificial Noise Revisited  

OpenAIRE

The artificial noise (AN) scheme, proposed by Goel and Negi, is being considered as one of the key enabling technology for secure communications over multiple-input multiple-output (MIMO) wiretap channels. However, the decrease in secrecy rate due to the increase in the number of Eve's antennas is not well understood. In this paper, we develop an analytical framework to characterize the secrecy rate of the AN scheme as a function of Eve's signal-to-noise ratio (SNR), Bob's S...

Liu, Shuiyin; Hong, Yi; Viterbo, Emanuele

2014-01-01

421

Essentials of artificial intelligence  

CERN Document Server

Since its publication, Essentials of Artificial Intelligence has beenadopted at numerous universities and colleges offering introductory AIcourses at the graduate and undergraduate levels. Based on the author'scourse at Stanford University, the book is an integrated, cohesiveintroduction to the field. The author has a fresh, entertaining writingstyle that combines clear presentations with humor and AI anecdotes. At thesame time, as an active AI researcher, he presents the materialauthoritatively and with insight that reflects a contemporary, first hand

Ginsberg, Matt

1993-01-01

422

Radioactive Iodine Treatment for Hyperthyroidism  

Science.gov (United States)

... Radioactive Iodine for Hyperthyroidism Share: Fact Sheet Radioactive Iodine for Hyperthyroidism April, 2012 Download PDFs English Zulu ... prepare for RAI or surgery. How does radio