We present results from the laboratory experiments performed to study the behaviour of dense plumes in porous media using Caesium Nitrate (CsNO) as the solute. Specifically, we consider the case of fixed volume release of a dense fluid into a saturated porous medium of lighter density. Our experiments consider the injection volume and concentration of CsNO and the porous medium permeability as experimental variables. Our measurements show that the plume length and volume increase with time approximately as t. The mean concentration of the plume decreases with time as plume monotonically dilutes due to continuous mixing with the surrounding. From our measurements and with the help of dimensionless scaling, we present empirical models for the length, volume and mean concentration of the plume. Our results may be used to gain preliminary insights into the spatio-temporal evolution of plumes formed in the subsurface environment.
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http://dx.doi.org/10.1016/j.jenvrad.2024.107558 | DOI Listing |
J Environ Radioact
December 2024
Department of Civil Engineering, Indian Institute of Technology, Kanpur 208016, UP, India. Electronic address:
We present results from the laboratory experiments performed to study the behaviour of dense plumes in porous media using Caesium Nitrate (CsNO) as the solute. Specifically, we consider the case of fixed volume release of a dense fluid into a saturated porous medium of lighter density. Our experiments consider the injection volume and concentration of CsNO and the porous medium permeability as experimental variables.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2024
Department of Earth and Planetary Sciences, University of California, Davis, CA 95616.
Nat Plants
November 2024
Plant Sciences, University of California, Davis, Davis, CA, USA.
The global incidence of megafires is on the rise, leading to extensive areas being shrouded in dense smoke for prolonged periods, spanning days or weeks. Here, by integrating long-term regional observations of non-structural carbohydrate content in trees across California's Central Valley with spatiotemporal satellite data, we present compelling evidence that dense smoke plumes negatively impact carbohydrate stores in three tree species: Prunus dulcis, Pistacia vera and Juglans regia. Our findings show that the presence of smoke causes a significant decrease in total non-structural carbohydrates, with reductions in the accumulation of both soluble sugar and starch reserves.
View Article and Find Full Text PDFSci Total Environ
October 2024
Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil.
The Patos Lagoon estuary is a highly significant ecosystem where freshwater from a vast and densely populated area continuously flows into the Atlantic Ocean by coastal plumes, exporting not only freshwater but also sediment, nutrients, plastics, and other contaminants. In this work, numerical modeling tools together with field data were used to assess for the first time the capacity of the coastal plume to export microplastics (MPs) to the inner shelf under different hydrodynamic conditions. Two field surveys were conducted during plume events to quantify MP concentrations and validate the model approach.
View Article and Find Full Text PDFMaterials (Basel)
July 2024
State Key Laboratory of Precision Welding & Joining of Materials and Structures, Harbin Institute of Technology, Harbin 150001, China.
The detection of keyhole-induced pore positions is a critical procedure for assessing laser welding quality. Considering the detection error due to pore migration and noise interference, this research proposes a regional prediction model based on the time-frequency-domain features of the laser plume. The original plume signal was separated into several signal segments to construct the morphological sequences.
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