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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Environmental science & technology 29 (1995), S. 1796-1801 
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 36 (1998), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: One benefit of a coupled geochemistry/transport approach is that interactions between chemical constituents that can change the mobility of species (such as pH) can be treated explicitly, rather than lumping all of the geochemistry into a single term (i.e., the retardation factor). A two-tiered approach to modeling coupled geochemistry/transport is presented here, which allows a comparison of the results of different methods as well as better efficiency in modeling time. The codes ParSSim, a coupled transport code for supercomputers, and PHREEQC, an advective geochemistry code, were used to model Sr mobility under varying pH. The problem was based on liquid low level radioactive waste that was disposed at Oak Ridge National Laboratory (Oak Ridge, Tennessee) in a highly alkaline solution to try to enhance precipitation and sorption. Interactions with carbonate rock and ground water lowered the pH and led to mobilization of radionuclides such as 90Sr. Simulation of contaminant migration in this mixing environment requires a coupled geochemistry and transport model. The interplay between propagation of a pH front (which was retarded) and propagation of the Sr front leads to a fast-moving pulse of Sr as well as a strongly retarded front of Sr. This behavior could not have been predicted by a geochemistry or a transport code alone.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 24 (1990), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. 〈list xml:id="l1" style="custom"〉1 Forty lakes in the Colorado Front Range were sampled to examine the relationship between water chemistry and the distributions and shell characteristics of Pisidium species. Alkalinity, pH, and dissolved organic carbon contributed most to the classification of lakes according to the dominant Pisidium species. Alkalinity was also strongly correlated with mean clam weight for populations of P. casertanum, the most common of the five species collected.2 Historical evidence shows a reduction in the number of lakes occupied by clams and a constriction in the distributions of certain species. These changes have occurred mainly in lakes that now have low alkalinity.3 A role for acidification is suggested because the recorded changes in distributions have occurred during the last 20 years, coincident with a general decline in alkalinity in waters of the Front Range.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 10 (1980), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. The diel patterns of reproduction were studied for three rotifer populations from Lake Valencia, Venezuela. Significant departures from uniformity were recorded for egg eclosion and egg deposition rates in Keratella americana and Brachianus calyciflorus, but only from egg deposition rates in B. havanaensis. The existence of non-random reproduction has practical ramifications for studies of population dynamics and secondary production.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 459-463 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Normal spectral emittance measurements from 5000 to 400 cm−1, and normal total emittance measurements, were made for sapphire and polycrystalline aluminas using Fourier-transform infrared spectroscopy. Samples were dropped from a furnace into the nitrogen ambient of the spectrometer to the position where the internal global source is normally focused. Radiance was measured as the alumina cooled to derived emittances from 900 to 1450 K. The temperatures were determined from radiance measurements at 1027 cm−1 where alumina has zero reflectivity and transmittance. Standard deviations of total normal emittance measurements averaged over three drops were ≤0.3% of the averages.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @journal of ecclesiastical history 48 (1997), S. 445-467 
    ISSN: 0022-0469
    Source: Cambridge Journals Digital Archives
    Topics: History , Theology and Religious Studies
    Notes: The lurches from Catholicism to Protestantism and back which occurred in the reigns of Henry VIII, his son and two daughters produced dramatic changes in the liturgies, decorative fittings, and even, on occasions, the architecture of the country's cathedrals. Yet, despite these changes, there was a real sense in which cathedrals were at the eye of the confessional storms which raged about them. It is true that, as part of the Henrician reform process, the monastic corporations at Carlisle, Durham, Peterborough, Ely, Norwich, Canterbury, Rochester, Osney, Winchester, Westminster, Gloucester, Worcester and Bristol had been first dissolved and then refounded as ‘cathedrals of the new foundation’, the monks replaced by minor canons and prebendaries. Once this upheaval was over, however, the new foundation cathedrals underwent little further institutional change. Those cathedrals which had been staffed by secular priests before the Reformation (known as cathedrals of the old foundation), moreover, survived almost wholly untouched. In both new and old foundations, the same administrative and financial structures continued to support dignitaries and liturgical officers whose only obvious function remained the celebration of liturgy, despite the rejection of opus Dei and its accompanying theology of good works.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 32 (1994), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Multiport ground-water sampling systems in five deep core holes near DOE's Y-12 facility at Oak Ridge, Tennessee provide data on the three-dimensional distribution of ground-water types and chemical evolution processes. Interpretation of ground-water chemistry, coupled with data on the primary and authigenic mineralogy from drill core, indicates the ground water evolves chemically by three main processes: (1) open system dissolution of calcite and dolomite at shallow depths to produce Ca-Mg-HCO3 waters; (2) irreversible dissolution of gypsum, which causes dedolomitization and leads to the formation of Ca-Mg-SO4 waters at deeper levels; and (3) mixing with deep brines to form saline Na-Ca-Cl waters. Evidence for dedolomitization included the precipitation of authigenic calcite in gypsum dissolution cavities, decrease in ground-water pH, and increases in dissolved Ca, Mg, and SO4. In this study, we document the dedolomitization process along a relatively short (〈 2000 ft) flow path in low permeability Paleozoic carbonates. Mixing of the shallower ground water with an Na-Ca-Cl brine thought to be present at depth can account for the progressive increase in salinity of ground water with depth and the precipitation of authigenic barite and celestite. The mixing process could be a combination of diffusion from below, diffusion from older matrix water into fractures, or advective mixing.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 40 (2004), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : Historical flow records are used to estimate the regulatory low flows that serve a key function in setting discharge permit limits through the National Pollutant Discharge Elimination System, which provides a nationwide mechanism for protecting water quality. Use of historical records creates an implicit connection between water quality protection and climate variability. The longer the record, the more likely the low flow estimate will be based on a broad set of climate conditions, and thus provides adequate water quality protection in the future. Unfortunately, a long record often is not available at a specific location. This analysis examines the connection between climate variability and the variability of biologically based and hydrologically based low flow estimates at 176 sites from the Hydro-Climatic Data Network, a collection of stream gages identified by the USGS as relatively free of anthropogenic influences. Results show that a record of 10 to 20 years is necessary for satisfactory estimates of regulatory low flows. Although it is possible to estimate a biologically based low flow from a record of less than 10 years, these estimates are highly uncertain and incorporate a bias that undermines water quality protection.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 39 (2003), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : The maximum concentration of a regulated substance that is allowed in a wastewater effluent usually is determined from the amount of dilution provided by the receiving water. Dilution flow is estimated from historical data by application of statistical criteria that define low flow conditions for regulatory purposes. Such use of historical data implies that the past is a good indicator of future conditions, at least for the duration of a discharge permit. Short records, however, introduce great uncertainty in the estimation of low flows because they are unlikely to capture events with recurrence frequencies of multiple years (e.g., ENSO events or droughts). We conducted an analysis of daily flows at several gages with long records in the South Platte River basin of Colorado. Low flows were calculated for successive time blocks of data (3-, 5-, 10-, and 20-years), and these were compared with low flows calculated for the entire period of record (〉 70 years). In unregulated streams, time blocks of three or five years produce estimates of low flows that are highly variable and consistently greater than estimates derived from a longer period of record. Estimates of low flow from 10-year blocks, although more stable, differ from the long term estimates by as much as a factor of two because of climate variation. In addition, the hydrographs of most streams in Colorado have been influenced by dams, diversions, or water transfers. These alterations to the natural flow regime shorten the record that is useful for analysis, but also tend to increase the calculated low flows. The presence of an upward trend in low flows caused by water use represents an unanticipated risk because it fails to incorporate societal response to severe drought conditions. Thus, climate variability poses a significant risk for water quality both directly, because it may not be represented adequately in the short periods of the hydrologic record that are typically used in permits, and indirectly, through its potential to cause altered use of water during time of scarcity.
    Type of Medium: Electronic Resource
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  • 10
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    Unknown
    West Chester, Pa. : Periodicals Archive Online (PAO)
    College Literature. 14:1 (1987:Winter) 32 
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