scholarly journals Local and global trace plutonium contributions in fast breeder legacy soils

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chris Tighe ◽  
Maxi Castrillejo ◽  
Marcus Christl ◽  
Claude Degueldre ◽  
Jeremy Andrew ◽  
...  
Keyword(s):  
Structural Change ◽  
Isotopic Ratio ◽  
Fast Neutrons ◽  
Fast Breeder Reactor ◽  
Trace Level ◽  
Plutonium Concentration ◽  
Local Contribution ◽  
Specific Activities ◽  
Insight Into ◽  
Mass Concentrations

AbstractTrace-level plutonium in the environment often comprises local and global contributions, and is usually anthropogenic in origin. Here, we report estimates of local and global contributions to trace-level plutonium in soil from a former, fast-breeder reactor site. The measured 240Pu/239Pu ratio is anomalously low, as per the reduced 240Pu yield expected in plutonium bred with fast neutrons. Anomalies in plutonium concentration and isotopic ratio suggest forensic insight into specific activities on site, such as clean-up or structural change. Local and global 239Pu contributions on-site are estimated at (34 ± 1)% and (66 ± 3)%, respectively, with mass concentrations of (183 ± 6) fg g−1 and (362 ± 13) fg g−1. The latter is consistent with levels at undisturbed and distant sites, (384 ± 44) fg g−1, where no local contribution is expected. The 240Pu/239Pu ratio for site-derived material is estimated at 0.05 ± 0.04. Our study demonstrates the multi-faceted potential of trace plutonium assay to inform clean-up strategies of fast breeder legacies.

scholarly journals Leaf and root pectin methylesterase activity and 13C/12C stable isotopic ratio measurements of methanol emissions give insight into methanol production in Lycopersicon esculentum

2011 ◽  
Vol 191 (4) ◽  
pp. 1031-1040 ◽  
Author(s):  
Patricia Yoshino Oikawa ◽  
Brian M. Giebel ◽  
Leonel da Silveira Lobo O’Reilly Sternberg ◽  
Lei Li ◽  
Michael P. Timko ◽  
...  
Keyword(s):  
Lycopersicon Esculentum ◽  
Isotopic Ratio ◽  
Pectin Methylesterase ◽  
Methanol Production ◽  
Stable Isotopic ◽  
Stable Isotopic Ratio ◽  
Insight Into

scholarly journals Strengthening Our Collaborative Approaches for Advancing Equity and Justice

2019 ◽  
Vol 46 (1_suppl) ◽  
pp. 5S-8S ◽  
Author(s):  
Michelle C. Kegler ◽  
Tom Wolff ◽  
Brian D. Christens ◽  
Frances Dunn Butterfoss ◽  
Vincent T. Francisco ◽  
...  
Keyword(s):  
Structural Change ◽  
Community Organizing ◽  
Health Inequities ◽  
Community Change ◽  
Community Collaboration ◽  
Theme Issue ◽  
Structural Racism ◽  
Inclusive Processes ◽  
Economic Injustice ◽  
Insight Into

The Principles for Collaborating for Equity and Justice are explicit about addressing social and economic injustice, structural racism, and community organizing to facilitate resident power and ownership. They also focus on structural change, an acknowledgment of complexity, and the need to thoughtfully build on decades of practice and scholarship on collaborating for community change. This special theme issue of Health Education & Behavior includes 10 articles that highlight these principles and provide insight into the complexities, challenges, and rewards of collaborating in ways that are intentional about advancing health equity through inclusive processes and shared goals to address social determinants of health. We provide a brief overview of the articles and identify community organizing and building resident power as possible strategies that should be combined with, complement, or in some cases replace, our more commonplace multisectoral coalitions if we hope to reduce health inequities through community collaboration.

scholarly journals Pressure induced superconductivity in MnSe

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
T. L. Hung ◽  
C. H. Huang ◽  
L. Z. Deng ◽  
M. N. Ou ◽  
Y. Y. Chen ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Structural Change ◽  
High Temperature Superconductivity ◽  
The Rich ◽  
Related Compounds ◽  
Insight Into

AbstractThe rich phenomena in the FeSe and related compounds have attracted great interests as it provides fertile material to gain further insight into the mechanism of high temperature superconductivity. A natural follow-up work was to look into the possibility of superconductivity in MnSe. We demonstrated in this work that high pressure can effectively suppress the complex magnetic characters of MnSe, and induce superconductivity with Tc ~ 5 K at pressure ~12 GPa confirmed by both magnetic and resistive measurements. The highest Tc is ~ 9 K (magnetic result) at ~35 GPa. Our observations suggest the observed superconductivity may closely relate to the pressure-induced structural change. However, the interface between the metallic and insulating boundaries may also play an important role to the pressure induced superconductivity in MnSe.

scholarly journals The Ocean Bomb Radiocarbon Inventory Revisited

Radiocarbon ◽  
2013 ◽  
Vol 55 (3) ◽  
pp. 1580-1594 ◽  
Author(s):  
Anne Mouchet
Keyword(s):  
Model Calibration ◽  
Isotopic Ratio ◽  
Piston Velocity ◽  
Modeling Studies ◽  
C Cycle ◽  
Bomb Radiocarbon ◽  
Insight Into ◽  
Simplified Form

Large discrepancies exist among data-based estimates and model reconstructions of the ocean bomb radiocarbon inventory. In order to resolve this gap, it has been proposed that the CO2 piston velocity should be revised downward (Sweeney et al. 2007; Müller et al. 2008). This article compares the transient 14C distributions in the ocean obtained with different formulations of the isotopic ratio commonly used in modeling studies. It is found that both the CO2 increase and the air-sea CO2 flux significantly contribute to the 1990 ocean bomb 14C inventory, by around 10% each. Moreover, these 2 processes explain more than 25% of the inventory difference between 1974 and 1990. These results imply that, as already argued by Naegler (2009), inventories based on observations that lack information about CO2 invasion are underestimated. Further, this work provides insight into the reasons for discrepancies among model results. It suggests that while a comprehensive isotopic formulation is needed when addressing the global 14C cycle, a simplified form is more relevant for model calibration and piston velocity assessment based on currently available bomb 14C inventories.

scholarly journals Insight into the photophysics of strong dual emission (blue & green) producing graphene quantum dot clusters and their application towards selective and sensitive detection of trace level Fe3+ and Cr6+ ions

RSC Advances ◽  
2020 ◽  
Vol 10 (45) ◽  
pp. 26613-26630
Author(s):  
Ganapathi Bharathi ◽  
Devaraj Nataraj ◽  
Sellan Premkumar ◽  
Padmanaban Saravanan ◽  
Daniel T. Thangadurai ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Trace Level ◽  
Dual Emission ◽  
Schematic Representation ◽  
Graphene Quantum Dot ◽  
Pl Emission ◽  
Cluster Type ◽  
Insight Into ◽  
Strong Dual ◽  
Type Sample

Schematic representation for the origin of blue and green emissions, and the resultant PL emission spectra from the GQD interconnected cluster-type sample.

scholarly journals Synthesizing Knowledge about Structural Change in Agriculture: The Integration of Disciplines and Aggregation Levels

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 601
Author(s):  
Stefan Mann
Keyword(s):  
Structural Change ◽  
Common Sense ◽  
Structural Changes ◽  
The Other ◽  
Review Of The Literature ◽  
Units Of Analysis ◽  
Societal Level ◽  
Economic Perspectives ◽  
Integration Of Disciplines ◽  
Insight Into

It is common sense that it needs social and economic perspectives to understand structural changes in agriculture. The current study asserts that, likewise, the integration of the farm level (micro), the sectoral level (meso), and the societal level (macro) are needed to gain insight into the system of agricultural structures. Following a review of the literature, these three levels were integrated in a cycle in which the interdependencies between different units of analysis were evaluated. The study concludes that it enhances the understanding of structural change on each level if the other levels are also taken into account. It therefore contributes not only to the literature on agriculture, but also to the discussion about the rationale of an analytical meso-level between the analysis on micro- and macro-levels.

scholarly journals Evidence of Tectonic Control on the Geochemical Features of the Volatiles Vented along the Nebrodi-Peloritani Mts (Southern Apennine Chain, Italy)

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17
Author(s):  
Francesco Italiano ◽  
Pietro Bonfanti ◽  
Salvatore Roberto Maugeri
Keyword(s):  
Continuous Monitoring ◽  
Isotopic Ratio ◽  
Accumulation Rate ◽  
Tectonic Setting ◽  
Metamorphic Rocks ◽  
Fault Rupture ◽  
Mantle Helium ◽  
Locked Fault ◽  
Insight Into ◽  
Apennine Chain

Investigations carried out over the southernmost portion of the Apennine chain (Nebrodi-Peloritani Mountains, Sicily, Italy) reveal a close connection between the tectonic setting and the regional degassing of CO2-dominated volatiles. The geochemical features of the collected gases show that the pristine composition has been modified by gas-water interaction (GWI) and degassing processes. The 3He/4He isotopic ratio in the range of 0.7-2.8 Ra highlights variable contributions of mantle-derived helium, representing an unusual feature for the crustal regime of the study areas characterized by the widespread presence of 4He-producer metamorphic rocks. The degassing of mantle helium is coherent with the tectonics and related to the NW-SE extensional regime of the Calabro-Peloritan Arc (CPA). We propose that the degassing regime as well as the geochemical features of both the dissolved and bubbling gases is closely connected to the strain accumulation rate, inducing almost no temporal changes and insignificant deep-originated fluid contributions to the locked fault volumes. Investigations including discrete and continuous monitoring and degassing-rate estimations are useful tools to gain a better insight into the evolution of seismogenesis, considering the fault rupture as the final stage of a seismic cycle.

Fast Breeder Reactor Core Concept to Improve Nuclear Proliferation Resistance

2010 ◽  
Author(s):  
Koji Fujimura ◽  
Satoshi Itooka ◽  
Takeshi Nitawaki
Keyword(s):  
Isotope Composition ◽  
Isotopic Ratio ◽  
Nuclear Proliferation ◽  
Reactor Core ◽  
Resistance Index ◽  
Fast Breeder Reactor ◽  
Core Concept ◽  
Fission Rate ◽  
Decay Heat ◽  
Breeding Ratio

A sodium-cooled MOX-fueled FBR core concept to improve nuclear proliferation resistance was proposed. First, we set an index for the nuclear proliferation resistance. In a previous study, reactor-grade Pu was defined such that the Pu-240 isotopic ratio was larger than 18%. Another study defined nuclear proliferation resistance with the Pu-238 isotopic ratio considering its higher spontaneous fission rate and decay heat. We tentatively use the total isotope composition ratio of Pu-238 and Pu-240 as a proliferation resistance index in line with the earlier studies. Next, we designed the sodium-cooled mixed-oxide (MOX)-fueled core concept with the breeding ratio (BR) of over 1.1 without a radial blanket. To attain the index for nuclear proliferation resistance, we added minor actinides (MAs) to the axial blanket fuel (AB). Contents of MAs in the AB to achieve the proliferation resistance index were evaluated. For the case of Np as a representative MA, the minimum content of Np to achieve the index was 3%. And, for the case of loading all MAs, the minimum content of MAs was 10.5%.

Sign in / Sign up

Export Citation Format

Share Document