scholarly journals An experimental search for a correlation between outdoor 222Rn concentration and 210Pb activity in air particulate samples

2018 ◽  
Vol 33 (1) ◽  
pp. 112-116 ◽  
Author(s):  
Elio Tomarchio
Keyword(s):  
Gamma Ray ◽  
Experimental Tests ◽  
Air Transport ◽  
Weak Correlation ◽  
Air Concentration ◽  
Air Masses ◽  
222Rn Concentration ◽  
Air Particulate ◽  
210Pb Activity ◽  
Lead 210

This work was aimed to search for a correlation between outdoor 222Rn air concentration and 210Pb activity in particulate samples collected on a filter. The existence of a correlation could support the hypothesis that both 222Rn and its long-lived product 210Pb are embedded into the same air masses and undergo the same air transport phenomena. Lead-210 activity was determined by means of gamma ray spectrometric measurement carried out a few days after the sampling whereas 222Rn concentration was measured through a commercial monitor. Experimental tests allowed to obtain a weak correlation between 222Rn and 210Pb air concentration as a preliminary result due to high uncertainties of outdoor 222Rn concentration measurements.

scholarly journals Determination of 7Be, 210Pb and 22Na Activity in Air and Rainwater samples by Gamma-ray Spectroscopy

2019 ◽  
Vol 24 ◽  
pp. 108
Author(s):  
M. Savva ◽  
M. Anagnostakis
Keyword(s):  
Atmospheric Aerosol ◽  
Activity Concentration ◽  
Gamma Ray ◽  
Cosmogenic Radionuclides ◽  
Air Masses ◽  
Accuracy And Precision ◽  
Engineering Department ◽  
Lead 210

The activity concentration of cosmogenic radionuclides in atmospheric aerosol has been used in many applications, such as air mass transport models and solar activity reconstructions. One of the most studied cosmogenic radionuclides is 7Be which is being monitored at the Nuclear Engineering Department of the National Technical University of Athens (NED- NTUA) since many years, with high accuracy and precision. Sodium-22 is another cosmogenic radionuclide met in such studies, however less reported due to its very low activity concentration, of the order of 1 μBq/m3 [1], [2] – roughly four orders of magnitude lower than that of 7Be. Besides cosmogenic radionuclides, radionuclides of terrestrial origin like the 222Rn progeny 210Pb are also used in atmospheric aerosol studies. Lead-210 serves as an ideal tracer of continental air masses because 222Rn emission from oceans and lakes is negligible (<1%) compared to land sources. However, its deposition exhibits geographic and seasonal variations depending on 226Ra content of the top soils, soil-porosity and meteorology of a particular region [3]. Values reported for 210Pb activity in the air range from 0.1 to 3.4 mBq/m3 [4]. During this research, an investigation regarding the detection of 210Pb and 22Na in atmospheric aerosol and the determination of 7Be/22Na ratio has been conducted at NED-NTUA. Sampling and analysis methods were appropriately selected to allow for the detection of all three nuclides in aerosol samples. In order to study the role of precipitation in surface air 7Be, 210Pb and 22Na activity concentration, a procedure for collecting and analyzing rainwater was also developed. From the results obtained so far it is concluded that with the sampling and analysis procedures followed, 210Pb can be easily determined with reasonable accuracy. As far as 22Na is concerned, it was concluded that it can be detected although with high uncertainty, since its activity concentration is within the limits of detection.

Impact of dust and sand storms on the aviation operation and assessment of conditions for their occurrence at aerodromes in European Russia

2020 ◽  
Vol 4 ◽  
pp. 78-95
Author(s):  
A.R. Ivanova ◽  
◽  
E.N. Skriptunova ◽  
N.I. Komasko ◽  
A.A. Zavialova ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Dust Storms ◽  
European Russia ◽  
Air Transport ◽  
Review Of Literature ◽  
Dust Transport ◽  
Air Masses ◽  
The Past ◽  
Sand Storm ◽  
The Impact

A review of literature on the impact of dust and sand storms on the air transport operation is presented. Observational data on dust storms at the aerodromes of European Russia for the period of 2001-2019 are analyzed. The seasonal variations in dust transport episodes at aerodromes and its relationship with visibility changes are discussed. The characteristics of dusty air masses and advection are given. It is concluded that the frequency of dust transfer episodes for the aerodromes under study has decreased over the past five years, except for Gumrak aerodrome (Volgograd). Keywords: dust storm, sand storm, aviation, visibility, seasonal variations, aerodrome оf European Russia

scholarly journals Measurement of 14C Concentrations of Stratospheric CO2 by Accelerator Mass Spectrometry

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 745-752 ◽  
Author(s):  
Toshio Nakamura ◽  
Takakiyo Nakazawa ◽  
Nobuyuki Nakai ◽  
Hiroyuki Kitagawa ◽  
Hideyuki Honda ◽  
...  
Keyword(s):  
Transport Mechanism ◽  
Sampling Method ◽  
Lower Stratosphere ◽  
Mass Movement ◽  
Vertical Mixing ◽  
Air Transport ◽  
Air Mass ◽  
Air Masses ◽  
Air Samples ◽  
Accelerator Mass Spectrometer

In order to measure the concentrations of anthropogenically influenced gases in the stratosphere, we have collected air samples from the lower stratosphere since 1985, by a balloon-borne cryogenic sampling method, developed at the Institute of Space and Astronautical Science (ISAS). Air samples of ≃16 liters at STP were collected in the stratosphere at altitudes from 18.6 to 30.4 km, over the northeastern part of Japan (39.5°N, 139–142°E), on 1 September 1989. We conducted 14C analyses to study the vertical and horizontal air-mass movement in the stratosphere, and to investigate the air transport mechanism between troposphere and stratosphere. Carbon dioxide (containing a few mg carbon) was separated cryogenically from the air samples, and the 14C concentration of the CO2 was measured by a Tandetron accelerator mass spectrometer, using Fe-graphite targets prepared by reducing CO2 on Fe-powder with hydrogen in a Vycor tube at 650°. The 14C concentrations, expressed as Δ14C, of CO2 were 267–309‰ at altitudes of 21–30 km, and 134‰ at 19–20 km. The Δ14C values at 21–30 km were higher than those of the current tropospheric CO2, of around 80–200‰. The observed 14C concentrations, higher in the stratosphere than the troposphere, seem to be explained by large bomb-produced 14C inventories and/or high 14C production by cosmic rays, as well as weak vertical mixing of air masses in the stratosphere.

Damage Detection in RAPTOR Telescope Systems Using Time-Frequency Analysis Methods

2013 ◽  
Vol 588 ◽  
pp. 43-53 ◽  
Author(s):  
Ifigeneia Antoniadou ◽  
Keith Worden ◽  
Graeme Manson ◽  
Nikolaos Dervilis ◽  
S.G. Taylor ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Gamma Ray ◽  
Energy Operator ◽  
Experimental Tests ◽  
Energy Separation ◽  
Driving Mechanism ◽  
Time Frequency Analysis ◽  
Time Frequency ◽  
Remote Locations ◽  
Analysis Methods

The RAPTOR telescope systems are astronomical observatories that operate in remote locations in New Mexico searching for astrophysical transients called gamma-ray bursts. Their operating condition should remain at good levels in order to have accurate observations. Currently, the first component of the RAPTOR telescopes to fail is a capstan driving mechanism that operates in a run-to failure mode. The capstans wear relatively frequently because of their manufacturing material and can cause damage to other more expensive components, such as the drive wheels and the telescope optics. Monitoring the condition of these systems seems a reasonable solution since the unpredictable rate at which the capstans experience wear, in combination with the remote locations and high duty cycles of these telescope systems, make it unprofitable to choose a strategy of replacing the capstans at chosen intervals. Experimental tests of the telescope systems reported here recorded vibration signals during clockwise and counterclockwise rotations, similar to a motion known as "homing-sequence". The Empirical Mode Decomposition (EMD) method in combination with the Hilbert Transform (HT) and a new alternative method for the estimation of the instantaneous features of a signal that applies an energy tracking operator, called Teager-Kaiser Energy operator, and an energy separation algorithm to the data being analysed, are the time-frequency analysis methods used for analysis here.

scholarly journals Distributions of total and size-fractionated particulate <sup>210</sup>Po and <sup>210</sup>Pb activities along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise

2018 ◽  
Vol 15 (17) ◽  
pp. 5437-5453 ◽  
Author(s):  
Yi Tang ◽  
Maxi Castrillejo ◽  
Montserrat Roca-Martí ◽  
Pere Masqué ◽  
Nolwenn Lemaitre ◽  
...  
Keyword(s):  
North Atlantic ◽  
Phase Correlation ◽  
Small Particles ◽  
Oxygen Utilization ◽  
Two Phase ◽  
The North ◽  
210Pb Activity ◽  
Vertical Distributions ◽  
The North Atlantic ◽  
Lead 210

Abstract. Vertical distributions of total and particulate polonium-210 (210Po) and lead-210 (210Pb) activities in the water column were measured at 11 stations in the North Atlantic during the GEOTRACES GA01 transect: GEOVIDE cruise in May–June 2014. Total 210Po activity was on average 24 % lower than 210Pb activity in the upper 100 m, and it was closer to unity in the mesopelagic (100–1000 m). The partitioning coefficients (Kd) along the transect suggest the preferential association of 210Po relative to 210Pb onto particles. The prominent role of small particles in sorption was confirmed by the observation that over 80 % of the particulate radionuclide activity was on small particles. To account for the observed surface water 210Po ∕ 210Pb disequilibria, particulate radionuclide activities and export of both small (1–53 µm) and large (>53 µm) particles must be considered. A comparison between the GEOVIDE total particulate 210Po ∕ 210Pb activity ratios (ARs) and the ratios in previous studies revealed a distinct geographic distribution, with lower particulate ARs in the high-latitude North Atlantic (including this study) and Arctic in relation to all other samples. For the samples where apparent oxygen utilization (AOU) was calculated at the same depth and time as the 210Po ∕ 210Pb AR (40 stations including this study), there was a two-phase correlation between the total particulate AR and AOU, likely reflecting the nature of the particles and demonstrating the forces of remineralization and radionuclide decay from particles as they age.

scholarly journals Experimental Investigation of Artificial Aeration on a Smooth Spillway with a Crest Pier

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1383 ◽  
Author(s):  
Juan Luna-Bahena ◽  
Oscar Pozos-Estrada ◽  
Víctor Ortiz-Martínez ◽  
Jesús Gracia-Sánchez
Keyword(s):  
Shock Waves ◽  
Hydraulic Structure ◽  
Standing Waves ◽  
Experimental Tests ◽  
Air Entrainment ◽  
Air Concentration ◽  
Cavitation Damage ◽  
Stepped Spillways ◽  
Artificial Aeration ◽  
And Shock Waves

Crest piers placed on overflow spillways induce standing waves at the downstream end of them and the supercritical flow expands after flowing past the rear of the pier. The expanding flow from each side of a pier will intersect and form disturbances or shock waves that travel laterally as they move downstream and eventually reach the chute sidewalls. Recently, investigations regarding crest piers are related with artificial aeration on stepped spillways to eliminate the risk of cavitation damage. However, there is a lack of studies on standing and shock waves in smooth spillways concerning the air entrainment into the flow in presence of crest piers. This paper presents the study of the combined effect on air entrainment of a crest pier and an aerator on the bottom of a smooth spillway (configuration 1). For comparison, experimental tests were developed in the spillway without pier, that is in presence of aerator only (configuration 2). The configuration 1 results show that the air concentration distribution on the spillway bottom across the width and length of the chute increases in comparison with configuration 2, reducing even more the risk of cavitation damage and enhancing the safety of the hydraulic structure.

scholarly journals Pipes to Earth's subsurface: the role of atmospheric conditions in controlling air transport through boreholes and shafts

2018 ◽  
Vol 9 (3) ◽  
pp. 1141-1153 ◽  
Author(s):  
Elad Levintal ◽  
Nadav G. Lensky ◽  
Amit Mushkin ◽  
Noam Weisbrod
Keyword(s):  
Large Diameter ◽  
Absolute Humidity ◽  
Field Measurements ◽  
Barometric Pressure ◽  
Atmospheric Temperature ◽  
Air Transport ◽  
Atmospheric Conditions ◽  
Air Masses ◽  
Diurnal Cycles

Abstract. Understanding air exchange dynamics between underground cavities (e.g., caves, mines, boreholes, etc.) and the atmosphere is significant for the exploration of gas transport across the Earth–atmosphere interface. Here, we investigated the role of atmospheric conditions in controlling air transport inside boreholes using in situ field measurements. Three geometries were explored: (1) a narrow and deep shaft (0.1 m wide and 27 m deep), ending in a large underground cavity; (2) the same shaft after the pipe was lowered and separated from the cavity; and (3) a deep large-diameter borehole (59 m deep and 3.4 m wide). Absolute humidity was found to be a reliable proxy for distinguishing between atmospheric and cavity air masses (mainly during the winter and spring seasons) and thus to explore air transport through the three geometries. Airflow directions in the first two narrow-diameter geometries were found to be driven by changes in barometric pressure, whereas airflow in the large-diameter geometry was correlated primarily with the diurnal cycles of ambient atmospheric temperature. CO2 concentrations of ∼2000 ppm were found in all three geometries, indicating that airflow from the Earth's subsurface into the atmosphere may also be significant in the investigation of greenhouse gas emissions.

scholarly journals Airborne Radioactivity in Hot Lab of Nuclear Medicine

2017 ◽  
Vol 9 (2) ◽  
pp. 159-166 ◽  
Author(s):  
J. Ferdous ◽  
N. Sharmin ◽  
A. Begum ◽  
A. Begum
Keyword(s):  
Nuclear Medicine ◽  
Filter Paper ◽  
Gamma Ray ◽  
Natural Radionuclides ◽  
Work Place ◽  
Gamma Ray Spectrometry ◽  
Air Filter ◽  
Air Sampler ◽  
Air Particulate ◽  
Airborne Radioactivity

In this study, identification and measurement of gamma emitting radionuclides contaminant in air inside the hot lab at the Institute of Nuclear Medicine have been carried out. Air particulate collection has been performed by suction of indoor air through filter paper using Staplex air sampler. The radioactivities of Pb-212, Pb-214, Ac-228, Bi-214, K-40, I-131 and Tc-99m captured by the filter paper were assessed using gamma-ray spectrometry. The observed activities of natural  radionuclides in air samples ranged from 0.59 to 295 mBq/m3 with average 143±0.003 mBq/m3 for Pb-212;  13.55 to 1911 mBq/m3 with average 402±0.007  mBq/m3 for Pb-214;  0.69 mBq/m3 to 571 mBq/m3 with average 57.33±0.009  mBq/m3 for Ac-228;  7.85 to 2192 mBq/m3 with average 543±0.014 mBq/m3 for Bi-214  and from 9.89 mBq/m3 to 256 mBq/m3 with average 92.9±0.052 mBq/m3 for K-40. The activities of artificial radionuclides in air filter ranged from 0.19 to 60.67 mBq/m3 with average 6.4±0.0 mBq/m3 for I-131; 0.25 to 40.27 mBq/m3 with average 4.17±0.0 mBq/m3 for Tc-99m. The activity of I-131 is compared with the reported values of other countries of the world. This demonstrated that the work place condition is satisfactory and the level of protection provided to the worker is sufficient.

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