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Diagnosing Microbiologically Influenced Corrosion
Published in Torben Lund Skovhus, Dennis Enning, Jason S. Lee, Microbiologically Influenced Corrosion in the Upstream Oil and Gas Industry, 2017
Jason S. Lee, Brenda J. Little
The stable isotopes of sulfur (32S and 34S) naturally present in any sulfate source are selectively metabolized during sulfate reduction by SRB, and the resulting sulfide is enriched in 32S (Chambers and Trudinger 1979). The 34S accumulates in the starting sulfate as the 32S is removed and becomes concentrated in the sulfide. Little et al. (1993) demonstrated sulfur isotope fractionation in sulfide corrosion deposits resulting from activities of SRB within biofilms on copper surfaces. 34S accumulated in sulfide-rich corrosion products; 34S was concentrated in the residual sulfate in the culture medium. Accumulation of the lighter isotope was related to surface derivatization or corrosion as measured by weight loss. Use of this technique to identify SRB-related corrosion requires sophisticated laboratory procedures.
The Santa Ana River: The challenge of maximizing the use of an urban river
Published in Peter J. Dillon, Management of Aquifer Recharge for Sustainability, 2002
A. S. Hutchinson, G.D. Woodside
The cornerstone of the SARWQH Study is hydrogeologic characterization, which provides the framework for understanding water quality changes that occur during percolation and subsurface flow. Some wells directly adjacent to the recharge facilities were originally anticipated to provide water samples of recharge river water with minimal subsurface residence time. Tritium-helium age dating of groundwater indicated that initial assumptions regarding flow to nearby wells were overly simplistic because of the presence of complex flow patterns (Davisson et al. 1996a). Additional tritium-helium age dating and three recharge tracer tests using xenon isotopes and sulfur hexafluoride have identified the predominant flow paths emanating from SAR and other recharge facilities (Davisson et al., 1999b; Gamlin et al., 2001). These tests also provided data for individual wells indicating the travel time of recharge water to the well and the amount of dilution of recharge water that occurs between the recharge facility and the well. Characterization of wells with known subsurface travel times and dilution for water recharged at specific basins provides a monitoring network that was used to evaluate water quality changes along defined flow paths. This approach is fundamental to understanding the water quality changes that occur during groundwater flow.
Absorption Spectroscopy and Its Implementation
Published in Helmut H. Telle, Ángel González Ureña, Laser Spectroscopy and Laser Imaging, 2018
Helmut H. Telle, Ángel González Ureña
The top and bottom spectral traces correspond to the IR-absorption spectrum before and after irradiation, respectively. Note that the before-irradiation spectrum is shown for higher spectral resolution (see Mathi et al. 2008), revealing part of the ro-vibrational band structure; the positions of the Q-branch maxima for the stable isotopes of sulfur are indicated by the arrows; the spectral features for the most abundant isotopes 32S and 34S (the natural abundance of all stable isotopes is tabulated next to the spectrum) are shown as blue and green traces, respectively. In addition, the positions of the CO2-laser lines, relevant for this particular SF6 vibrational transition, are included in the figure.
Photodissociation dynamics of the methylsulfinyl radical at 248 nm
Published in Molecular Physics, 2019
Isaac A. Ramphal, Chin Lee, Daniel M. Neumark
The existence of several other channels was investigated. Reasonable photofragments would include S (m/z = 32) + CH3O (m/z = 31), OH (m/z = 17) + CH2S (m/z = 46), SH (m/z = 33) + CH2O (m/z = 30), H2 (m/z = 2) + HCSO (m/z = 61), and CH2 (m/z = 14) + HSO (m/z = 49). For the mass-to-charge ratios indicated above, signal was only observed at m/z = 46 and m/z = 49. The m/z = 46 feature was entirely consistent with dissociative ionisation of the CH3S photofragment to CH2S+ based on the virtually identical TOF spectra, and the m/z = 49 feature is due to photofragments containing heavy isotopes of sulfur (see below). None of the aforementioned reactions appear to be operative with 248 nm photoexcitation of methylsulfinyl.