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Isotope contribution to geochemical investigations for aquifer storage and recovery
Published in Peter J. Dillon, Management of Aquifer Recharge for Sustainability, 2002
C. Le Gal La Salle, J. Vanderzalm, J. Hutson, P. Dillon, P. Pavelic, R. Martin
Groundwater was sampled on a weekly basis after breakthrough at a specific observation well. Chloride concentrations were analyzed by ICP-MS (Australian Water Quality Center). The isotopic analyses were performed at the CSIRO Isotope Laboratory Service (Adelaide). The concentration of stable isotopes are expressed in the conventional way, as the difference in ratio of heavy to light isotopes between the samples and the Vienna standard mean ocean water (V-SMOW). The difference in ratio is normalized to the standard and expressed in per mill: δ18O(18O16O)sample−(18O16O)SMOW(18O16O)SMOWx1000 Oxygen-18 and deuterium concentration were measured by mass spectrometry, with error of 0.15 and 1 ‰ respectively. Data for first injection cycle for the injectant, 4m well and the piezometer 50 m north of the ASR well, at a depth of 134–139 m, are presented in this paper.
Overcoming the challenges of flow forecasting in a data poor region
Published in Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2023
Nicholas Kouwen, Amber Langmuir, Lakshminarayanan Ramanathan, Gordon Gallant
Many of the hydrological abstractions in CHARM have been validated with field observations (Bingeman, Kouwen, and Soulis 2006). A list of WATFLOOD based publications can be found at www.watflood.ca. In particular, Stadnyk et al. (2005) and Stadnyk and Holmes (2020) showed how stable isotope tracers in streamflow can be used to verify that the partitioning of surface and ground water in the model is correct. Furthermore, as quoted from their abstract, Stadnyk et al. (2013) describe “a novel methodology for large-scale (>1000 km2) hydrological model calibration and validation using stable water isotopes founded on the rigorous constraints imposed by the need to conserve both water mass and stable isotopes simultaneously.” WATFLOOD is the only hydrological modelling system where parallel water, oxygen 18 and deuterium transport models are combined. Although stable isotopes were not used in this study, their use in WATFLOOD in other forest–bog–wetland dominated watersheds in northern Canada has demonstrated that relevant hydrological processes are reasonably incorporated in CHARM.
Energy expenditure in professional flat jockeys using doubly labelled water during the racing season: Implications for body weight management
Published in European Journal of Sport Science, 2018
George Wilson, Daloni Lucas, Catherine Hambly, John R. Speakman, James P. Morton, Graeme L. Close
The use of the doubly labelled water (DLW) stable isotope method is deemed the ‘gold standard’ for practically measuring TEE in free living mammals (Schoeller, Ravussin, et al., 1986; Speakman & Krol, 2010) and is a method that allows for TEE to be measured over a prolonged period of time (days). The DLW method uses the principles of indirect calorimetry to measure TEE from the turnover rates of two stable isotopes, deuterium (2H) and oxygen 18 (18O) (Speakman, 1997). Since the method involves only the oral administration of stable isotopes and the collection of urine samples, it overcomes the limitations that have previously occurred in the limited previous work in this field (Wilson, Sparks, et al., 2013). The capacity to measure TEE in a working week of professional jockeys can provide an insight into the typical energy output which can then be considered when tailoring appropriate nutritional guidelines for jockeys to make weight. Moreover, it could further aid nutritional strategies to understand any potential differences in TEE that may occur at different periods of the flat racing season. Ultimately, this may assist jockeys in making weight more effectively without resorting to severe dehydration techniques, and thereby resulting in improved athlete welfare.
Studies on properties of coated para-aramid fabric samples developed for military applications – post UVA-340 exposure
Published in The Journal of The Textile Institute, 2023
R. G. Revaiah, T. M. Kotresh, Balasubramanian Kandasubramanian
It is well known that p-aramid shows remarkable properties with respect to mechanical and fire resistance properties (Hamouda, 2018). When exposed to UV radiation, it loses its mechanical properties drastically (Zhang et al., 2006). The photodegradation of p-aramid leads to embrittlement, loss of colour or brightness, formation of surface cracks, etc., after unpredictable time (Li et al., 2013). Critical wavelength for Kevlar for photodegradation is between 300 and 450 nm and mechanism of photodegradation of Kevlar is extensively studied by Toy (1987) using 1H NMR and oxygen-18-labelled atmosphere. Energetic UV radiation can break C–O, C–C and C–H bonds near exposed surface leading to the formation of free radicals, which in turn react with molecular oxygen to form peroxy radicals. The absorption of UV radiation by p-aramid fabric induces both oxidative degradation as well as crosslinking. The mechanism of p-aramid degradation under the influence of UV reported in the literature is provided in Figure 1a,b (Arrieta et al., 2011; Carlsson et al., 1975). Extensive work has been done on the effects of UV on high performance materials. Several methods have been tried to slower or arrest the UV-induced degradation by coating surface with TiO2 (Chen et al., 2011) and ZnO where the former being UV active protects vulnerable p-aramid underneath (Azpitarte et al., 2017). One of the main drawbacks of these lamination or coating with UV active ZnO or TiO2 is that, coatings get abraded on harsh abrasive surfaces during routine military operations. The coated fabric sample used in the present study when subjected to Martindale abrasion, found to offer very high abrasion resistance (more than 200,000 Martindale abrasion cycle) compared to the base fabric (hole formation took place at 40,000 Martindale abrasion cycles).