Search results for "RADIOACTIVITY"
showing 10 items of 334 documents
Recent evolution of the multi-isotopic radioactive content in ice of Livingston Island, Antarctica.
1999
The temporal arrangement of the ice layers that are produced in ecosystems with perpetual snows form situations that greatly favour the study of the temporal evolution of the radioactive fallout that occurs in the said zones, whether this fallout is natural or artificial in origin. This allows one to investigate the causes of the fallout and the mechanisms transporting the radionuclides involved from their source point to the study zone, as well as their subsequent behaviour in that zone. There are special difficulties involved in this type of study in Antarctica. Some are of a general character deriving from the conditions of extreme climate and isolation which complicate the processes of …
Eksperimentālā fizika, 2. sējums: Elektrība. Magnetisms. Atombūve
1925
The radium Era: radioactivity and advertising of miracle products in the dawn of the 20th century in Spain
2020
El descubrimiento de la radiactividad a finales del siglo XIX proporcionó el conocimiento de un nuevo fenómeno natural que fue utilizado como reclamo sin validación científica en un repertorio de productos, remedios y terapias que en el primer cuarto del siglo XX se anunciaron profusamente en la prensa española. Las experiencias de los manantiales con el agua radiactiva o los emanatorios urbanos fueron algunos de los casos más frecuentes de esas terapias o productos milagro en los que la publicidad de la época utilizaba la ciencia desde el abuso, el desconocimiento o las falsas atribuciones para prometer curaciones para todo tipo de dolencias sin ninguna efectividad práctica. The discovery …
A Bayesian approach to assess data from radionuclide activity analyses in environmental samples
2007
A Bayesian statistical approach is introduced to assess experimental data from the analyses of radionuclide activity concentration in environmental samples (low activities). A theoretical model has been developed that allows the use of known prior information about the value of the measurand (activity), together with the experimental value determined through the measurement. The model has been applied to data of the Inter-laboratory Proficiency Test organised periodically among Spanish environmental radioactivity laboratories that are producing the radiochemical results for the Spanish radioactive monitoring network. A global improvement of laboratories performance is produced when this pri…
Environmental radioactivity at Stromboli (Aeolian Islands)
2002
HPGe gamma spectrometry, thermoluminescence dosimetry, X-ray diffractometry and fluorescence techniques have been used to analyze the natural radionuclides content of soil and rock samples, air kerma and geochemical features on the island of Stromboli, belonging to the Aeolian Islands, in the Mediterranean Sea. The 214Bi, 238Ac, and 40K contents obtained are in agreement with the magmatic evolution of the rock formation, as shown by the correlations between radionuclide and chemical elements abundacies, depending on the various magmatic differentiation mechanisms. Correlations between radiometric, lithological and geochemical data have been assessed in order to obtain some hints on the geoc…
Natural radioactivity in a volcanic island: Ustica, Southern Italy
1997
Abstract Gamma-ray spectrometric measurements were performed on rocks and soils of the island of Ustica (Southern Italy) to quantify the concentrations of the natural radionuclides. The 238U, 232Th, and 40K concentration ranges (15–164, 16–174, and 201–1350 Bq kg−1, respectively) were compared with mineralogical and chemical data obtained by XRD and XRF analyses. The observed levels of the primordial radionuclides corresponded to the magmatological features of the rocks. Soil samples generally showed specific gamma-ray activities not directly correlatable to those measured in the underlying rocks. A survey was also perormed to measure air kerma in outdoor and indoor environments using therm…
Correlation of radioactivity measurements, air kerma rates and geological features of Sicily
2006
Abstract Sicily, the largest Mediterranean island (with an extension of about 25 000 km 2 ), exhibits a very wide variety of lithologies, ranging from sedimentary to metamorphic and volcanic rocks. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied to air kerma values measured by thermoluminescent dosimetry in several sites and to data of radionuclide concentrations, geochemical and mineralogical features of rocks and soils sampled in 29 sites of Sicily to point out similarities among different lithologies. The study was devoted to find multiple correlations and allow a better classification of Sicilian lithotypes. Samples of rocks and soils have be…
Response of GAFChromic® HD-V2 film dosimeter in 10-300 Gy dose range for radiation testing of electronic devices
2019
The study reported in this paper aimed to investigate the response of a GAFChromic? HD-V2 film dosimeter in the dose range between 10 and 300 Gy, normally used to perform irradiation tests on electronic devices with a 60Co gamma-ray irradiator. The well-defined linearity of response in terms of absorbance as a function of absorbed dose, easiness of handling and data analysis of irradiated dosimeters, reproducibility, stability, and insensitivity to visible light and most of the environmental parameters, make HD-V2 film a flexible, inexpensive and reliable dose measurement device. The study has shown a fogging effect of the dosimeter response since its value changes over time. Strategies and…
Dating of a sediment core in the Palermo Bay (Sicily, Italy)
2007
An extensive study of sediment cores in the Palermo Bay has been carried during the last two years. Main goal of the research was to study the environmental pollution of the area, using foraminifers as an environmental indicator.
Analysis of 7Be and 210Pb concentration and 7Be/210Pb activity ratio in ground level air in Palermo (Italy).
2019
Recently a renewed interest has been put on the use of radioactive tracers to study transport and mixing processes in the atmosphere. Among the most commonly used radioactive tracers in the atmosphere, 7Be and 210Pb have assumed an ever-increasing importance. Beryllium-7 is the product of the interaction of cosmic rays with Nitrogen and Oxygen nuclei. Its cosmogenic origin makes the measured concentrations strongly dependent on the geographical position and seasonal cycles. It emits 478 keV gamma photons and has a half-life of about 53 days.