Techniques and Methods

Michler, Sprenger

doi:10.3139/9781569905586.002

Cited by 2 publications

(2 citation statements)

References 10 publications

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“…10 Recently, there has been growing concern about the contaminant effect caused by this herbicide because it has been detected in groundwater in different places exceeding the concentrations considered as safe. 11 Thus, it is not strange that several studies have been focused to investigate the degradation of ISOX and DKN. 1,2 Mougin et al suggested that the DKN chemical oxidation to benzoic acid implies the loss of the cyano group of the molecule, but they did not verify the existence of this reaction pathway.…”

Section: Introductionmentioning

confidence: 99%

A computational study of the chemical reactivity of isoxaflutole herbicide and its active metabolite using global and local descriptors

Mendoza-Huízar

Ríos-Reyes

Zuñiga-Trejo

2020

JSCS

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In this work, the chemical reactivity of isoxaflutole (ISOX) and diketonitrile (DKN) was analyzed at the X/6-311++G(2d,2p) (where X = = B3LYP, M06, M06L and ?B97XD) level of theory, in the gas and aqueous phases. The results indicate that DKN, the active metabolite of ISOX, is more stable than isoxaflutole in both phases. ISOX is susceptible to electrophilic and free radical reactions through the isoxazole ring; while the carbonyl group is attacked by nucleophiles. For DKN nucleophilic and free radical attacks are expected on the aromatic ring, while electrophilic attacks are favored on the oxygen atom of the carbonyl groups. The results suggest that the cleavage of the N?O bond in the isoxazole ring is possible through electrophilic and free radical attacks, while electrophilic and free radical attacks will favor substitutions on the carbonyl groups of DKN.

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Section: Introductionmentioning

confidence: 99%

A computational study of the chemical reactivity of isoxaflutole herbicide and its active metabolite using global and local descriptors

Mendoza-Huízar

Ríos-Reyes

Zuñiga-Trejo

2020

JSCS

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“…We considered three models in this study to first generate synthetic temperature and head fields and then analyze these data using heat as a tracer software tools ( Figure 1a). We first applied the numerical groundwater flow and transport model SUTRA (Voss & Provost, 2019) in 1D to forward model head, temperature, and vertical water flux fields subject to diurnal and semi-diurnal surface boundary conditions. Since the SUTRA-modeled water fluxes were known at each point in time and space, standard heat tracing software packages (VFLUX2 and 1DTempPro) were used in an inverse manner to investigate the ability of these tools to process the SUTRA-simulated results and reproduce the known vertical fluxes under tidal forcing.…”

Section: Methodsmentioning

confidence: 99%

Using Heat to Trace Vertical Water Fluxes in Sediment Experiencing Concurrent Tidal Pumping and Groundwater Discharge

LeRoux

Kurylyk

Briggs

et al. 2021

Water Resources Research

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Heat has been widely applied to trace groundwater‐surface water exchanges in inland environments, but it is infrequently applied in coastal sediment where head oscillations induce periodicity in water flux magnitude/direction and heat advection. This complicates interpretation of temperatures to estimate water fluxes. We investigate the convolution of thermal and hydraulic signals to assess the viability of using heat as a tracer in environments with tidal head oscillations superimposed on submarine groundwater discharge. We first generate sediment temperature and head time series for conditions ranging from no tide to mega‐tidal using a numerical model (SUTRA) forced with periodic temperature and tidal head signals. We then analyze these synthetic temperature time series using heat tracing software (VFLUX2 and 1DTempPro) to evaluate if conventional terrestrial approaches to infer fluxes from temperatures are applicable for coastal settings. We consider high‐frequency water flux variability within a tidal signal and averaged over tidal signals. Results show that VFLUX2 analytical methods reasonably estimated the mean discharge fluxes in most cases but could not reproduce the flux variability within tidal cycles. The model results further reveal that high‐frequency time series of water fluxes varying in magnitude and direction can be accurately estimated if paired temperatures and hydraulic heads are analyzed using numerical models (e.g., 1DTempPro) that consider both dynamic hydraulic gradients and thermal signals. These results point to the opportunity to incorporate pressure sensors within heat tracing instrumentation to better assess sub‐daily flux oscillations and associated reactive processes.

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Techniques and Methods

Cited by 2 publications

References 10 publications

A computational study of the chemical reactivity of isoxaflutole herbicide and its active metabolite using global and local descriptors

A computational study of the chemical reactivity of isoxaflutole herbicide and its active metabolite using global and local descriptors

Using Heat to Trace Vertical Water Fluxes in Sediment Experiencing Concurrent Tidal Pumping and Groundwater Discharge

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