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141.
Ola Ahlqvist Johannes Keukelaar Karim Oukbir 《International journal of geographical information science》2013,27(5):475-496
In search for methods to handle imprecision in geographical information this paper explores the use of rough classification to represent uncertainty. Rough classification is based on rough set theory, where an uncertain set is specified by giving an upper and a lower approximation. Novel measures are presented to assess a single rough classification, to compare a rough classification to a crisp one and to compare two rough classifications. An extension to the error matrix paradigm is also presented, both for the rough-crisp and the roughrough cases. An experiment on vegetation and soil data demonstrates the viability of rough classification, comparing two incompatible vegetation classifications covering the same area. The potential uses of rough sets and rough classification are discussed and it is suggested that this approach should be further investigated as it can be used in a range of applications within geographic information science from data acquisition and analysis to metadata organization. 相似文献
142.
A. Mautner H. A. Maples T. Kobkeatthawin V. Kokol Z. Karim K. Li A. Bismarck 《International Journal of Environmental Science and Technology》2016,13(8):1861-1872
Copper is a major problem in industrial wastewater streams, seriously affecting the quality of potential drinking water. Several approaches, including continuous membrane processes or batch-wise application of adsorbents, are in use to tackle this problem. Unfortunately, these processes suffer from their particular drawbacks, such as low permeance or disposal of saturated adsorbents. However, a combination of these processes could constitute a step towards a more efficient copper removal solution. Here, we present a nanopaper ion-exchanger prepared from cellulose nanofibrils produced from fibre sludge, a paper industry waste stream, for the efficient, continuous removal of copper from aqueous solutions. This nanopaper ion-exchanger comprises phosphorylated cellulose nanofibrils that were processed into nanopapers by papermaking. The performance of these phosphorylated nanopaper membranes was determined with respect to their rejection of copper and permeance. It was shown that this new type of nanopaper is capable of rejecting copper ions during a filtration process by adsorption. Results suggest that functional groups on the surface of the nanopapers contribute to the adsorption of copper ions to a greater extent than phosphate groups within the bulk of the nanopaper. Moreover, we demonstrated that those nanopaper ion-exchangers could be regenerated and reused and that in the presence of calcium ions, the adsorption capacity for copper was only slightly reduced. 相似文献
143.
John C. Ayers Steven Goodbred Gregory George David Fry Laura Benneyworth George Hornberger Kushal Roy Md. Rezaul Karim Farjana Akter 《Geochemical transactions》2016,17(1):4
Background
High salinity and arsenic (As) concentrations in groundwater are widespread problems in the tidal deltaplain of southwest Bangladesh. To identify the sources of dissolved salts and As, groundwater samples from the regional shallow Holocene aquifer were collected from tubewells during the dry (May) and wet (October) seasons in 2012–2013. Thirteen drill cores were logged and 27 radiocarbon ages measured on wood fragments to characterize subsurface stratigraphy.Results
Drill cuttings, exposures in pits and regional studies reveal a >5 m thick surface mud cap overlying a ~30 m thick upper unit of interbedded mud and fine sand layers, and a coarser lower unit up to 60 m thick dominated by clean sands, all with significant horizontal variation in bed continuity and thickness. This thick lower unit accreted at rates of ~2 cm/year through the early Holocene, with local subsidence or compaction rates of 1–3 mm/year. Most tubewells are screened at depths of 15–52 m in sediments deposited 8000–9000 YBP. Compositions of groundwater samples from tubewells show high spatial variability, suggesting limited mixing and low and spatially variable recharge rates and flow velocities. Groundwaters are Na–Cl type and predominantly sulfate-reducing, with specific conductivity (SpC) from 3 to 29 mS/cm, high dissolved organic carbon (DOC) 11–57 mg/L and As 2–258 ug/L, and low sulfur (S) 2–33 mg/L.Conclusions
Groundwater compositions can be explained by burial of tidal channel water and subsequent reaction with dissolved organic matter, resulting in anoxia, hydrous ferric oxide (HFO) reduction, As mobilization, and sulfate (SO4) reduction and removal in the shallow aquifer. Introduction of labile organic carbon in the wet season as rice paddy fertilizer may also cause HFO reduction and As mobilization. Variable modern recharge occurred in areas where the clay cap pinches out or is breached by tidal channels, which would explain previously measured 14C groundwater ages being less than depositional ages. Of samples collected from the shallow aquifer, Bangladesh Government guidelines are exceeded in 46 % for As and 100 % for salinity.144.
Karim C. Abbaspour 《大气与海洋》2013,51(4):686-698
Abstract The performances of eight methods for estimating daily energy‐limited evapotranspiration (Ee) were compared with reliable values for the Peace River region of British Columbia. They included the methods of Priestley and Taylor (PT), Jensen and Haise (JH), Hargreaves (H) and Makkink (M), the first and second equations of Baier and Robertson (BR1 and BR2), and the modified methods of Blaney and Criddle (BC) and Thornthwaite (T). The reference data were obtained from previous workers, who in 1977 and 1979 made micrometeorological measurements of Ee using the Bowen ratio method. The relationships between estimated and measured Ee values excluding the T method in 1977 had correlation coefficients (R) ranging from 0.65 to 0.84. These were not significantly different at the 5% level. The Standard Errors of the Estimate (SEE) ranged from 0.43 to 1.69 mm d?1. The PT, JH, BR1 and T methods had low SEE values, whereas the BR2, H, BC and M methods had high SEE values. Six of the eight methods (PT, JH, H, M, BR2 and BC) were calibrated for local conditions using 1979 data. After calibration, the methods were tested with the 1977 data. The results indicated significant improvement in the fit of four of the methods (H, M, BR2 and BC). Overall, it was concluded that after calibration, six of the eight methods had predictive power and fit that were not significantly different at the 5% level. 相似文献
145.
Hourly sea level records from three stations in eastern Canada (Québec-Lauzon, Harrington-Harbour and Halifax) are analyzed both in frequency domain from 1970 to 1979 and in time domain during 1973. At the three stations, the deterministic model explains 90 to 96% of the total variability of sea level. The semidiurnal and diurnal tides contribute largely to its variations. The residual series, less than 10% of the initial variations of sea level, contain irregular values including extreme values of seiches and storm surges. Such random variations are analyzed and modeled following the method described by Box and Jenkins (1976). The long period variations (2 to 30 days) can be attributed to meteorological forcing (atmospheric pressure and winds). The short period variations (some hours to one day) can be attributed to longitudinal seiches, semidiurnal and diurnal atmospheric tides, and inertial oscillations. The water discharge from the St. Lawrence River contributes 29% of the monthly residual sea level at Qué 相似文献
146.
Jennyfer Miot Karim Benzerara Andreas Kappler Martin Obst Fériel Skouri-Panet Nicole Posth Gordon E. Brown Jr. François Guyot 《Geochimica et cosmochimica acta》2009,73(3):696-1446
Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM). All detected minerals consisted mainly of amorphous iron phosphates, but based on their morphology and localization, three types of precipitates could be discriminated: (1) mineralized filaments at distance from the cells, (2) globules of 100 ± 25 nm in diameter, at the cell surface and (3) a 40-nm thick mineralized layer within the periplasm. All of those phases were shown to be intimately associated with organic molecules. Periplasmic encrustation was accompanied by an accumulation of protein moieties. In the same way, exopolysaccharides were associated with the extracellular mineralized filaments. The evolution of cell encrustation was followed by TEM over the time course of a culture: cell encrustation proceeded progressively, with rapid precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria and in the extracellular precipitates reached complete oxidation within 6 days. While a progressive oxidation of Fe in the bacteria and in the medium could be observed, spatial redox (oxido-reduction state) heterogeneities were detected at the cell poles and in the extracellular precipitates after 1 day. All these findings provide new information to further the understanding of molecular processes involved in iron biomineralization by anaerobic iron-oxidizing bacteria and offer potential signatures of those metabolisms that can be looked for in the geological record. 相似文献
147.
We answer our critics and confirm the reality of a feature in the interstellar extinction curve near 2800 Å for stars showing abnormally low graphite absorption. 相似文献
148.
Hoyle F. Wickramasinghe N. C. Al-Mufti S. Karim L. M. 《Astrophysics and Space Science》1985,114(2):303-309
Whereas data for the extinction of starlight in the visible show the interstellar grains must be partially hollow, data in the ultraviolet show the vesicular interiors must be irregular. In particular, the absorbing materials responsible for excess extinction over a band centred at 2175 Å are required to be concentrated in irregularly distributed chromophores with dimensions of the order of or less than one-tenth of the whole grain.The laboratory measurements of absorptions produced by microorganisms agree very closely with astronomical observations for a large number of early-type stars. Since the interior structures of microorganisms are indeed highly irregular, the laboratory measurements made with microorganisms suspended in a fluid, can reasonably be transferred to microorganismsin vacuo.The characteristic dimension for the scattering of visible light by rod-like grains has in the past been taken to be rod diameters. An alternate interpretation with the characteristic dimension taken instead to be rod-oengths may turn out to have advantages in respect of data in the ultraviolet, as well as agreeing in scale with bacteria-like objects found in meteorites, and possibly also, in particles entering the Earth's atmosphere from the zodiacal cloud. 相似文献
149.
Karez is an indigenous method of irrigation in which groundwater is tapped by a tunnel. After running for some distance the tunnel comes out in the open and the water is conducted to the command area. Karez irrigation is practised in 22 countries from China to Chile including Pakistan. In Pakistan it is confined to the province of Balochistan which has a tribal society.Karez is an old and stable irrigation system of Pakistan. It is a community enterprise managed by tribal tradition and run by social control. Spacing of the karez, their types, life, length, discharge, land development and allocation, water distribution and management are important aspects of karez irrigation which have been discussed in this paper. Differences in karez maintenance and management produced by differences in tradition and customs of various tribes inhabiting Balochistan are brought out. Furthermore recent changes in Karez irrigation caused by changes in the socio-economic conditions are also analysed. 相似文献
150.