New Fluorophore Design

Heagy, Michael D.

doi:10.1002/9781118019580.ch13

Cited by 2 publications

(3 citation statements)

References 52 publications

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“…This analysis has benefited from the ease with which fields, fluxes and charges are readily calculated and visualized within the SimPEG framework, particularly when used in conjunction with Jupyter notebooks. Source codes for all of the examples in this paper are available in the form of Jupyter notebooks at https://github.com/simpeg-research/heagy-2018-dc-casing (Heagy 2018); our aim in providing these notebooks is to allow readers to reproduce the results shown and also adapt the parameters and extend the analysis to address their questions.…”

Section: Discussionmentioning

confidence: 99%

“…Source codes for all of the simulations shown are open source, licensed under the MIT license, and are available as Jupyter notebooks at: https://github.com/simpeg-research/heagy-2018-dc-casing (Heagy 2018). The examples in the paper have been selected with an emphasis on examining physical principles; however, we envision that the Jupyter notebooks included with this publication could serve as useful survey design tools.…”

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Direct current resistivity with steel-cased wells

Heagy

Oldenburg

2019

Geophysical Journal International

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The work in this paper is motivated by the increasing use of electrical and electromagnetic methods in geoscience problems where steel-cased wells are present. Applications of interest include monitoring carbon capture and storage and hydraulic fracturing operations, as well as detecting flaws or breaks in degrading steel-casings -such wells pose serious environmental hazards. The general principles of electrical methods with steel-cased wells are understood, and several authors have demonstrated that the presence of steel-cased wells can be beneficial for detecting signal due to targets at depth. However, the success of a DC resistivity survey lies in the details. Secondary signals might only be a few percent of the primary signal. In designing a survey, the geometry of the source and receivers, and whether the source is at the top of the casing, inside of it, or beneath the casing will impact measured responses. Also the physical properties and geometry of the background geology, target, and casing will have a large impact on the measured data. Because of the small values of the diagnostic signals, it is important to understand the detailed physics of the problem and also to be able to carry out accurate simulations. This latter task is computationally challenging because of the extreme geometry of the wells, which extend kilometers in depth but have millimeter variations in the ra-arXiv:1810.12446v2 [physics.geo-ph] 8 Jul 2019 2 Lindsey J. Heagy, Douglas W. Oldenburg dial direction, and the extreme variation in the electrical conductivity (typically 5-7 orders of magnitude between the casing and the background geology).In this paper, we adopt a cylindrical discretization for numerical simulations to investigate three important aspects of DC resistivity in settings with steel-cased wells.(1) We examine the feasibility of using a surface-based DC resistivity survey for diagnosing impairments along a well in a casing integrity experiment. This parameter study demonstrates the impact of the background conductivity, the conductivity of the casing, the depth of the flaw, and the proportion of the casing circumference that is compromised, on amplitude of the secondary electric fields measured at the surface.(2) Next, we consider elements of survey design for exciting a conductive or resistive target at depth. We show that conductive targets generate stronger secondary responses than resistive targets, and that having an electrical connection between the target and well can significantly increase the measured secondary responses.(3) Finally, we examine common strategies for approximating the fine-scale structure of a steel cased well with a coarse-scale representation to reduce computational load. We show that for DC resistivity experiments, the product of the conductivity and the cross-sectional area of the casing is the important quantity for controlling the distribution of currents and charges along its length.To promote insight into the physics, we present results by plotting the currents, charges, and electric fi...

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Section: Discussionmentioning

confidence: 99%

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Direct current resistivity with steel-cased wells

Heagy

Oldenburg

2019

Geophysical Journal International

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“…ESIPT is essentially a photo-tautomerization process that occurs in the electronically excited state of a molecule (Scheme 1a), in which the proton-transfer tautomer emission reveals an anomalously large spectral red-shift with respect to absorption. This unique photophysical property leads to numerous practical optoelectronic applications, such as bioimaging, [1][2][3] fluorescent solar energy concentrators, 4,5 and UV-photostabilizers, [6][7][8] as well as chemosensors, [9][10][11] organic light-emitting devices, 12,13 laser dyes, [14][15][16] and molecular switches. [17][18][19] It has been well accepted that the driving force of ESIPT reaction comes from significant changes in the acidity and basicity of the involved groups.…”

Section: Introductionmentioning

confidence: 99%

A new class of N–H excited-state intramolecular proton transfer (ESIPT) molecules bearing localized zwitterionic tautomers

Stasyuk

Chen

et al. 2016

Phys. Chem. Chem. Phys.

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A series of new amino (NH)-type intramolecular hydrogen-bonding (H-bonding) compounds have been strategically designed and synthesized. These molecules comprise a 2-(imidazo[1,2-a]pyridin-2-yl)aniline moiety, in which one of the amino hydrogens was replaced with substituents of different electronic properties. This, together with the versatile capability for modifying the parent moiety, makes feasible comprehensive spectroscopy and dynamics studies of excited-state intramolecular proton transfer (ESIPT) as a function of N-H acidity. Different from other (NH)-type ESIPT systems where the ESIPT rate and exergonicity increase with an increase in the N-H acidity and hence the H-bonding strength, the results reveal an irregular relationship among ESIPT dynamics, thermodynamics and H-bond strength. This discrepancy may be rationalized by the localized zwitterionic nature of 2-(imidazo[1,2-a]pyridin-2-yl)aniline in the proton-transfer tautomer form, which is different from the π-delocalized tautomer form in other (NH)-type ESIPT systems.

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New Fluorophore Design

Cited by 2 publications

References 52 publications

Direct current resistivity with steel-cased wells

Direct current resistivity with steel-cased wells

A new class of N–H excited-state intramolecular proton transfer (ESIPT) molecules bearing localized zwitterionic tautomers

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