scholarly journals Preliminary Measurements of Be-10/Be-7 Ratio in Rainwater for Atmospheric Transport Analysis

2020 ◽  
Vol 7 (2) ◽  
pp. 145-151
Author(s):  
K. de los Ríos ◽  
C. Méndez-García ◽  
L. Acosta ◽  
R. García-Martínez ◽  
M. A. Martínez-Carrillo ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Metropolitan Areas ◽  
Atmospheric Transport ◽  
Isotopic Ratio ◽  
Preliminary Results ◽  
Atmospheric Flows ◽  
Decay Spectroscopy ◽  
Transport Analysis ◽  
Gamma Decay

The meteoric cosmogenic beryllium has been used as an essential geophysical tracer in the analysis of atmospheric flows and erosion soils since 1960. The first measurements Be-7 and Be-10 concentrations in rainwater from Mexico, have been carried out by using gamma decay spectroscopy and AMS techniques, respectively for each isotope. With this it was possible to report a preliminar value for the Be-10/Be-7 isotopic ratio in such environmental samples. The present work described preliminary results related to rainwater collected at mountain and metropolitan areas. Results are compared with predictions and previous measurements for both radioisotopes, observing a very sensible behavior particularly for the case of Be-7 activities.

scholarly journals β-γ and isomeric decay spectroscopy of 168Dy

2018 ◽  
Vol 178 ◽  
pp. 02023
Author(s):  
G.X. Zhang ◽  
H. Watanabe ◽  
F.G. Kondev ◽  
G.J. Lane ◽  
P.H. Regan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Excited States ◽  
Experimental Work ◽  
Isomeric State ◽  
Level Structure ◽  
Primary Beam ◽  
Average Intensity ◽  
Experimental Procedure ◽  
Preliminary Results ◽  
Decay Spectroscopy

This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the β decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.

Deconvolution of alpha liquid scintillation spectra for quantitative analysis of actinide elements in water samples

2004 ◽  
Vol 92 (3) ◽  
Author(s):  
Jean Aupiais
Keyword(s):  
Quantitative Analysis ◽  
Water Samples ◽  
Environmental Samples ◽  
Liquid Scintillation ◽  
Isotopic Ratio ◽  
Ratio Determination ◽  
Alpha Beta ◽  
Uranium Plutonium ◽  
Actinide Elements

SummaryThe reliability and accuracy of actinide measurement in environmental samples strongly depend on theThe intensity of the internal conversions for thorium, uranium, plutonium and americium have been calculated and normalised to the intensity of the main alpha transition. These data can be used to determine the activity of any above-mentioned actinide by alpha liquid scintillation with alpha/beta discrimination. The quantitative analysis and the isotopic ratio determination of several certified solutions of actinides demonstrate the validity of this approach.

scholarly journals Numerical Sensitivity Tests of Volatile Organic Compounds Emission to PM2.5 Formation during Heat Wave Period in 2018 in Two Southeast Korean Cities

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 331 ◽  
Author(s):  
Geum-Hee Yang ◽  
Yu-Jin Jo ◽  
Hyo-Jung Lee ◽  
Chang-Keun Song ◽  
Cheol-Hee Kim
Keyword(s):  
Heat Wave ◽  
Metropolitan Areas ◽  
Secondary Organic Aerosol ◽  
Atmospheric Transport ◽  
Wrf Model ◽  
Organic Aerosol ◽  
Photochemical Reactions ◽  
Wave Period ◽  
Voc Emissions ◽  
Volatile Organic

A record-breaking severe heat wave was recorded in southeast Korea from 11 July to 15 August 2018, and the numerical sensitivity simulations of volatile organic compound (VOC) to secondarily generated particulate matter with diameter of less than 2.5 µm (PM2.5) concentrations were studied in the Busan and Ulsan metropolitan areas in southeast Korea. A weather research and forecasting (WRF) model coupled with chemistry (WRF-Chem) was employed, and we carried out VOC emission sensitivity simulations to investigate variations in PM2.5 concentrations during the heat wave period that occurred from 11 July to 15 August 2018. In our study, when anthropogenic VOC emissions from the Comprehensive Regional Emissions Inventory for Atmospheric Transport Experiment-2015 (CREATE-2015) inventory were increased by approximately a factor of five in southeast Korea, a better agreement with observations of PM2.5 mass concentrations was simulated, implying an underestimation of anthropogenic VOC emissions over southeast Korea. The simulated secondary organic aerosol (SOA) fraction, in particular, showed greater dominance during high temperature periods such as 19–21 July, 2018, with the SOA fractions of 42.3% (in Busan) and 34.3% (in Ulsan) among a sub-total of seven inorganic and organic components. This is considerably higher than observed annual mean organic carbon (OC) fraction (28.4 ± 4%) among seven components, indicating the enhancement of secondary organic aerosols induced by photochemical reactions during the heat wave period in both metropolitan areas. The PM2.5 to PM10 ratios were 0.69 and 0.74, on average, during the study period in the two cities. These were also significantly higher than the typical range in those cities, which was 0.5–0.6 in 2018. Our simulations implied that extremely high temperatures with no precipitation are significantly important to the secondary generation of PM2.5 with higher secondary organic aerosol fraction via photochemical reactions in southeastern Korean cities. Other possible relationships between anthropogenic VOC emissions and temperature during the heat wave episode are also discussed in this study.

Data-based kernel density equations for probability distributions of releases of CTBT-relevant radioxenon isotopes from nuclear facilities and when arriving at IMS stations after atmospheric transport

2021 ◽  
Author(s):  
Martin Kalinowski ◽  
Boxue Liu
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Explosion ◽  
Atmospheric Transport ◽  
Isotopic Ratio ◽  
Probability Distributions ◽  
Kernel Density ◽  
Nuclear Research ◽  
Nuclear Facilities ◽  
Data Set

<p>For the International Monitoring System (IMS) to be effective, it is vital that nuclear explosion signals can be distinguished from natural and man-made radioactivity in the atmosphere. The International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) applies standard event screening criteria, with the objective of characterizing, highlighting, and thereby screening out, events considered to be consistent with natural phenomena or non-nuclear explosive, man-made phenomena. The objective of this study is to apply the kernel density (KD) approach to generate and investigate probability distributions of isotopic ratios for radioxenon releases from certain types of sources. The goal is to create probability density functions that could be applied e.g. with a Bayesian method to determine the probability whether an IMS observation can be explained by known sources or could possibly be caused by a nuclear explosion. KD equations for nuclear facility releases are derived from the data set of the radioxenon emission inventory of all nuclear power plants and all nuclear research reactors, as well as selected medical isotope production facilities in the calendar year 2014. For all types of sources, KD equations will be linked with isotopic ratio calculations that connect the sources and IMS stations as receiver.</p>

scholarly journals Estimation of Uranium Sources in Environmental Samples Using the Isotopic Ratio Determination

2020 ◽  
Author(s):  
Junko Shikimori ◽  
Takeshi Ohno ◽  
Yusuke Fukami ◽  
Yasuhito Igarashi
Keyword(s):  
Environmental Samples ◽  
Isotopic Ratio ◽  
Ratio Determination ◽  
Uranium Sources

scholarly journals Rapid $sup 15$N isotopic-ratio and total nitrogen analytical system for environmental samples

1975 ◽  
Author(s):  
J. A. Carter ◽  
J. R. Walton ◽  
R. L. Walker ◽  
D. R. Matthews
Keyword(s):  
Total Nitrogen ◽  
Environmental Samples ◽  
Isotopic Ratio ◽  
Analytical System

Ultra-trace determination of the 135Cs/137Cs isotopic ratio by thermal ionization mass spectrometry with application to Fukushima marine sediment samples

2019 ◽  
Vol 34 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Wenting Bu ◽  
Lei Tang ◽  
Xuemei Liu ◽  
Zhongtang Wang ◽  
Miho Fukuda ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Environmental Samples ◽  
Thermal Ionization Mass Spectrometry ◽  
Isotopic Ratio ◽  
Ionization Mass ◽  
Trace Determination ◽  
Sediment Samples ◽  
Thermal Ionization Mass ◽  
Ultra Trace

A new method was developed for determination of the 135Cs/137Cs isotopic ratio at the femtogram level in environmental samples.

Development of cryogenic extraction system for δ18O and δ2H measurement of water in soils and plants.

2021 ◽  
Author(s):  
Nunzio Romano ◽  
Carolina Allocca ◽  
Luisa Stellato ◽  
Fabio Marzaioli ◽  
Paolo Nasta
Keyword(s):  
Isotopic Composition ◽  
Soil Water ◽  
Isotope Composition ◽  
Isotopic Ratio ◽  
Plant Root ◽  
Root Water Uptake ◽  
Vacuum System ◽  
Operational Parameters ◽  
Vacuum Equipment ◽  
Preliminary Results

<p>The stable isotope composition of water (δ<sup>18</sup>O and δ<sup>2</sup>H) represents a useful tool to distinguish among different water pools along the soil-plant-atmosphere continuum. Using δ<sup>2</sup>H and δ<sup>18</sup>O as tracers helps gain a better understanding of plant root water uptake and dominant ecohydrological processes. To determine which pools of water are used for plant physiologic functions and returned to the atmosphere by transpiration, a common approach is to analyze the isotopic composition of water in both soil and plant. Cryogenic water extraction (CWE; Orlowski et al., 2016) is the most widely used laboratory-based technique to extract water from soil samples for isotopic analysis. However, recent studies have shown that the extraction conditions (time, temperature, and vacuum) and soil physical and chemical properties may affect the extracted soil-water isotope composition even significantly.</p><p>We have developed an efficient and cost-effective cryogenic vacuum equipment to extract water from soil or vegetation and this presentation aims at discussing some preliminary results. The equipment has been specifically designed to meet the following requirements: i) enable to quantify the accuracy of a CWE continuous flow extraction line, and ii) identify a specific extraction standard protocol for soil and vegetation samples. Two experiments have been carried out to evaluate the isotope fractionation induced by the system and how different operational parameters (i.e. times and temperature of extraction) can affect the results. Firstly, a known water isotopic ratio was processed by the vacuum system to determine the measurement accuracy and reproducibility by comparing pre- and post-processed water isotopic signatures. The likely causes of observed biases induced by sample processing are assessed and a relevant correction procedure is suggested. Subsequently, measurements were carried out on replicated samples taken from two differently-textured soils that, after being dried, were saturated in the laboratory up to different water content values with water of known isotopic composition. Also, plant samples were collected from plants grown in a greenhouse and irrigated with water of known isotopic composition.</p><p>Water from all samples was extracted by our CWE system and then analyzed using an isotope ratio mass spectrometer in Gas Bench mode for analyses and in temperature conversion elemental analysis (TC/EA) mode for. Preliminary results have quantified the isotope fractions on average of -1.6 ‰ for δ<sup>18</sup>O and 14.2 ‰ for δ<sup>2</sup>H. Normalization of stable isotopes from unknown samples according to observed fractionation has enabled the observed bias to become virtually zero, leading to a replicate reproducibility of δ<sup>18</sup>O and δ<sup>2</sup>H for soil water of 0.6 ‰ and 3 ‰, respectively. The analyses carried out up to now did not find statistical evidence that the soil types and soil-water contents may affect the extraction method and the accuracy of our protocol.</p>

scholarly journals Assessing the Diversity of Marine Bacterial β-Glucosidases by Capillary Electrophoresis Zymography

2001 ◽  
Vol 67 (10) ◽  
pp. 4896-4900 ◽  
Author(s):  
Jesús M. Arrieta ◽  
Gerhard J. Herndl
Keyword(s):  
Capillary Electrophoresis ◽  
Kinetic Parameters ◽  
North Sea ◽  
Marine Environment ◽  
Bacterial Communities ◽  
Environmental Samples ◽  
New Method ◽  
Preliminary Results ◽  
Fast Separation ◽  
Substrate Concentrations

ABSTRACT We propose a new method for the fast separation and detection of β-glucosidases in environmental samples. With this approach, β-glucosidases extracted from bacteria are evidenced by substrate-incorporated capillary electrophoresis (CE zymography) and their kinetic parameters can be determined by repeated injections using different substrate concentrations. Preliminary results obtained with natural bacterial communities from the coastal North Sea suggest that the diversity of β-glucosidases in the marine environment might be much higher than previously observed.

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