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Ir. Lahuddin M S Zulkifli Nasution 《湿地科学》2006,4(3):161-167
1 INTRODUCTIONQuality of chemical properties of flooded soils isgenerally determined by salinity and alkalinity,bothof these acts as inhibiting factors of plant growth.Thecorrelation of electrical conductivity and other analysisindex has been reported by … 相似文献
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Evolution of the Kivu Rift,East Africa: interplay among tectonics,sedimentation and magmatism 
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下载免费PDF全文 Douglas A. Wood Hubert J. Zal Christopher A. Scholz Cynthia J. Ebinger Irénée Nizere 《Basin Research》2017,29(Z1):175-188
The seismically and volcanically active Kivu Rift, in the western branch of the East African Rift System, is a type locale for studies of high‐elevation, humid‐climate rift basins, as well as magmatic basin development. Interpretations of offshore multi‐channel seismic (MCS) reflection data, terrestrial radar topography, lake bathymetry and seismicity data recorded on a temporary array provide new insights into the structure, stratigraphy and evolution of the Kivu rift. The Kivu rift is an asymmetric graben controlled on its west side by a ca. 110 km‐long, N‐S striking border fault. The southern basins of the lake and the upper Rusizi river basin are an accommodation zone effectively linking 1470 m‐high Lake Kivu to 770 m‐high Lake Tanganyika. MCS data in the eastern Kivu lake basin reveal a west‐dipping half graben with at least 1.5 km of sedimentary section; most of the ca. 2 km of extension in this sub‐basin is accommodated by the east‐dipping Iwawa normal fault, which bounds an intrabasinal horst. Lake Kivu experienced at least three periods of near desiccation. The two most recent of these approximately correlate to the African Megadrought and Last Glacial Maximum. There was a rapid lake level transgression of at least 400 m in the early Holocene. The line load of the Virunga volcanic chain enhances the fault‐controlled basin subsidence; simple elastic plate models suggest that the line load of the Virunga volcanic chain depresses the basin by more than 1 km, reduces flank uplift locally and broadens the depocentre. Not only do the voluminous magmatism and degassing to the lake pose a hazard to the riparian population, but our studies demonstrate that magmatism has important implications for short‐term processes such as lake levels, inflow and outlets, as well as long term modification of classic half‐graben basin morphology. 相似文献
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I. V. Buchko A. A. Sorokin V. A. Ponomarchuk A. V. Travin A. P. Sorokin Ir. V. Buchko 《Doklady Earth Sciences》2010,435(2):1560-1563
This article discusses the results of 40Ar/39Ar geochronological studies on the age of the gold-silver mineralization of the Dess occurrence hosted by the granitoids of
the Tynda-Bakaran rock complex, which is 129–128 Ma. This estimate coincides with the time of the formation of the Mo mineralization
(125–122 Ma) hosted by the rocks of the same rock complex. This allows dating the Au-Ag and Mo mineralizations from the same
ore formation period that manifests itself in the granitoids of the North Stanovoi metallogenic belt that were formed in the
environment of a transform continental margin. There exists the following sequence of changes in the mineral occurrences from
the south to the north: Au-Ag-Au-Mo(Au). 相似文献
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According to the present concept for final storage of spent nuclear fuel in Sweden, the spent fuel, encapsulated in copper or copper/steel canisters, will be placed in tunnels in a deep rock formation. The canisters will be surrounded by compacted bentonite clay acting as a buffer material. In connection with a safety analysis of such a storage facility, the total solubility of certain elements (e.g., uranium) as well as the transport properties (e.g., retardation due to sorption on mineral surfaces) of the long-lived radionuclides released from the canister have to be predicted or measured. The chemical conditions, governing the solubility and speciation of trace elements encountered in and around the repository depend on interactions between the ground water and the engineering materials in the repository and a production of oxidants due to radiolysis in the spent fuel. In the present study the speciation and solubility of uranium and neptunium in a bentonite-ground water system and in ground waters with compositions measured at a site at äspö, SE Sweden, have been calculated. The calculations have been carried out using a recent version of the geochemical computer code PHREEQE and the database HATCHES 5.0. Predictions of the uranium and neptunium concentrations in the ground water in the vicinity of a damaged high level waste repository have also been performed. The uranium concentration in the water in the bentonite barrier is predicted to be of the same order of magnitude or lower than that found in some granitic ground waters. For neptunium the calculations are uncertain due to the small amount of experimentally determined thermodynamic data and few verifications under the conditions (pH - Eh - carbonate concentration) considered. The predicted concentrations (ca 10–12 m, corresponds to ca 0.006 Bq/l) may be regarded as high, considering the high toxicity of neptunium and its long half-life. 相似文献
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Inversion of inline and broadside marine controlled‐source electromagnetic data with constraints derived from seismic data 下载免费PDF全文
下载免费PDF全文 Torgeir Wiik Janniche Irén Nordskag Eirik Øverland Dischler Anh Kiet Nguyen 《Geophysical Prospecting》2015,63(6):1371-1382
We present a structural smoothing regularization scheme in the context of inversion of marine controlled‐source electromagnetic data. The regularizing hypothesis is that the electrical parameters have a structure similar to that of the elastic parameters observed from seismic data. The regularization is split into three steps. First, we ensure that our inversion grid conforms with the geometry derived from seismic. Second, we use a seismic stratigraphic attribute to define a spatially varying regularization strength. Third, we use an indexing strategy on the inversion grid to define smoothing along the seismic geometry. Enforcing such regularization in the inversion will encourage an inversion result that is more intuitive for the interpreter to deal with. However, the interpreter should also be aware of the bias introduced by using seismic data for regularization. We illustrate the method using one synthetic example and one field data example. The results show how the regularization works and that it clearly enforces the structure derived from seismic data. From the field data example we find that the inversion result improves when the structural smoothing regularization is employed. Including the broadside data improves the inversion results even more, due to a better balancing between the sensitivities for the horizontal and vertical resistivities. 相似文献
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Fabien Gibert Irène Xuéref-Rémy Lilian Joly Martina Schmidt Juan Cuesta Kenneth J. Davis Michel Ramonet Pierre H. Flamant Bertrand Parvitte Virginie Zéninari 《Boundary-Layer Meteorology》2008,128(3):381-401
A network of remote and in-situ sensors was deployed in a Paris suburb in order to evaluate the mesoscale evolution of the
daily cycle of CO2 and related tracers in the atmospheric boundary layer (ABL) and its relation to ABL dynamics and nearby natural and anthropogenic
sources and sinks. A 2-μm heterodyne Doppler differential absorption lidar, which combines measurements of, (1) structure
of the atmosphere, (2) radial velocity, and (3) CO2 differential absorption was a particularly unique element of the observational array. We analyse the differences in the diurnal
cycle of CO, CO2, lidar reflectivity (a proxy for aerosol content) and H2O using the lidar, airborne measurements in the free troposphere and ground-based measurements made at two sites located few
kilometres apart. We demonstrate that vertical mixing dominates the early morning drawdown of CO and aerosol content trapped
in the former nocturnal layer but not the H2O and CO2 mixing ratio variations. Surface fluxes, vertical mixing and advection all contribute to the ABL CO2 mixing ratio decrease during the morning transition, with the relative importance depending on the rate and timing of ABL
rise. We also show evidence that when the ABL is stable, small-scale (0.1-km vertical and 1-km horizontal) gradients of CO2 and CO are large. The results illustrate the complexity of inferring surface fluxes of CO2 from atmospheric budgets in the stable boundary layer. 相似文献
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Summary An outline is given of a method of estimating the number of hours during which the combine harvester can be operated in a certain harvesting period. This method is based on a study of the relation between the daily rainfall and the hourly estimates by 60 observers of the possibility of combine harvesting (weather-working hours).Over the years 1964, 1965 and 1966, the relationship between the possibility to combine harvest and the rainfall has been summarized in a linear regression equation:y=a+b
1
x
1+b
2
x
2, withy=mean number of weather-working hours per day per half-monthly period, x1=mean daily rainfall per half-monthly period, x2=number of dry days per half-monthly period.For chosen percentiles of the frequency distribution ofy the corresponding number of weather-working hours in the same period can be estimated for future years. Taking the (two dimensional) frequency distribution of x1 and x2 as fixed, confidence intervals for the estimated number of weather-working hours can be calculated.
With 1 Figure 相似文献
Zusammenfassung Es wird eine Methode zur Abschätzung der Stundenzahl, während der ein Mähdrescher innerhalb einer bestimmten Ernteperiode eingesetzt werden kann, besprochen. Die Methode beruht auf einer Untersuchung über die Beziehung zwischen der täglichen Regenmenge und der Möglichkeit des Mähdrescher-Einsatzes, welche von 60 Beobachtern Stunde für Stunde geschätzt wurde (Arbeitswetter-Stunden).Die Beziehung zwischen der Möglichkeit des Mähdrescher-Einsatzes und der Regenmenge wurde für die Jahre 1964, 1965 und 1966 in einer linearen Regresionsgleichung dargestellt:y=a+b 1x1+b 2x2, woy=mittlere Zahl von Arbeitswetter-Stunden pro Tag je Monatshälfte, x1=mittlere tägliche Regenmenge pro Monatshälfte, x2=Zahl der Trockentage pro Monatshälfte.Man kann für ausgewählte Perzentile der Häufigkeitsverteilung vony die entsprechende Zahl der Arbeitswetter-Stunden in derselben Periode für künftige Jahre abschätzen.Aus der zweidimensionalen Häufigkeitsverteilung von x1 und x2 können Konfidenzbereiche für die geschätzte Zahl der Arbeitswetter-Stunden berechnet werden.
Résumé On discute une méthode permettant d'estimer le nombre d'heures durant lesquelles une moissonneuse-batteuse peut être engagée au cours d'une période déterminée de moisson. Cette méthode repose sur une recherche des relations existantes entre la somme journalière de précipitation et les possibilités d'utilisation de la machine, relevées d'heure en heure par 60 observateurs (heures employables de machine).La relation entre la quantité de précipitations et la possibilité d'emploi d'une moissonneuse-batteuse est représentée par des équations linéaires de régression pour 1964 aussi bien que pour 1965 et 1966:y=a+b 1x1+b 2x2. La signification des symboles est la suivante:y=le nombre moyen d'heures employables de machine par jour, calculé par un demi-mois,x 1=la quantité journalière moyenne de précipitaations par un demi-mois, x1=la quantité journalière moyenne de précipitaations par un demi-mois, x2=le nombre de jours secs par un demi-mois.Partant de percentiles choisis de la distribution de fréquences dey, il est possible d'éstimer le nombre d'heures employables des moissonneuse-batteuses dans la même période pour les années a venir.Disposant de la distribution de fréquences des deux variablesx 1 etx 2 on peut calculer des intervalles de confidence pour le nombre estimé d'heures employables de machine par jour.
With 1 Figure 相似文献