Theoretical and Applied Climatology - This study examined the effect of different attributes on regionalization of potential evapotranspiration (ETp) in Urmia Lake Basin (ULB), Iran, using the... 相似文献
In this paper, the effect of different curvatures on the spatial variation of coherent flow structure inside two physical
models with both strongly curved and mild multi-bend meanders is investigated. Three dimensional flow velocities at three
sequential meanders were measured using an Acoustic Doppler Velocity meter (Micro-ADV). Three dimensions of flow velocity
are classified into two major classes and eight different bursting events. The contribution probability and transition probability
of each zone is calculated from experimental data. The results indicated that the effect of curvature in sequential bends
was important particularly for strongly curved bends. The contribution probability of the events for strongly curved meanders
with relative curvature (Rc/B) of 2.6 were found to be higher than for mild curved meanders with relative curvature (Rc/B) of 4.43. The minimum contribution probability was found in external inward interaction event. In addition, analysis of
bursting events showed that the highest values of transition probabilities occurred in the stable organizations for both models.
The influences of different curvatures on distributions of the Reynolds shear stress, the turbulent kinetic energy, the streamwise
velocity and the vertical velocity were also shown to be in good agreement with eroded bed. The above results can be useful
for finding meandering patterns inside rivers and also in river training works. 相似文献
The Nasirabad manganese occurrence is located to the south of the Neyriz in the Fars province. Structurally and lithologically, this occurrence lies in the southwest part of the Zagros Thrust Belt and was deposited as Mn-nodules and interconnected ore-bearing interlayer's with radiolarite cherts in the vicinity of the Neyriz ophiolites. The present work deals with the geology and geochemistry of the Nasirabad manganese occurrence with a discussion of its genesis. High Mn/Fe (average 18.85) and high Ba (average 28,830 ppm) with low Pb (2.0 ppm) and LREE > HREE, Lan/Ndn (average 4.5), Dyn/Ybn (average 1.2) and negative Eu anomaly suggest distal hydrothermal source. The Co/Zn (average 2.2), Ce/La ratio (average 0.67) and trace element discrimination diagrams indicate hydrothermal–hydrogenous processes. Y/Ho ratio (average 24.85) and strong positive correlation coefficient between major oxides and some high field strength elements (HFSE) like; TiO2 vs Fe2O3 (r = 0.98), Al2O3 vs Zr (r = 0.97), Al2O3 vs Fe2O3 (r = 0.98), Zr vs K2O (r = 0.98), Nb vs TiO2 (r = 0.92), Th vs Fe2O3 (r = 0.76), Th vs MgO (r = 0.86) reveal the presence of volcaniclastics and (or) terrigenous detritals of mafic composition being deposited into the depositional basin. It seems that intermittent interlayering of mafic detrital material derived from volcanic eruption of the Neyriz island arc directly affected the physicochemical conditions of hydrothermal ore precipitation in this basin and consequently the Nasirabad manganese ores represent hydrothermal–hydrogenous geochemical characteristics. The Nasirabad is an example of non-sulphidic, oxic Mn-mineralization. Similar trend between the enrichment and depletion of some bioessential elements (e.g., Mn, As, Ba, Sr, Co, Ce) might have been resulted from selective sequestering of metal ions by microbial processes and hence hydrogenous characteristics may also be the result of biogenetic processes. Moreover the high dilution of distal hydrothermal exhalations by sea water cannot be ruled out. 相似文献
Phosphorus (P) desorption characteristics may be altered due to the biosolids decomposition during the incubation period. In our previous work we studied the phosphorus release kinetics in biosolids-amended calcareous soils with no prior incubation. The objectives of this work were (1) to assess the phosphorus desorption behavior in soils as influenced by biosolids after 5 months of incubation and (2) to evaluate the influences of six levels of the biosolids on phosphorus availability and salinity of soil. The results showed that the biosolids addition significantly increased the soil available P and salinity. The P availability and salinity of the soils increased as level of the biosolids application increased. However, there was no significant difference between some application rates for some soils. The results indicated that the incubation can affect the factors controlling the P release rate. Also, the results showed that the soil organic matter negatively affected the P desorption rate in the biosolids-treated soils. 相似文献
Cherty marbles of Hasan-Robat area, northwest of Isfahan, in the Sanandaj–Sirjan Zone of Iran preserves evidences of multiple deformational events. The Sanandaj–Sirjan Zone is the inner crystalline zone of the Zagros Orogen, which has been highly deformed and exhumed during continental collision between the Arabian Plate and Central Iran. The Hasan-Robat area is an example of the exposed Precambrian–Paleozoic basement rocks that stretched along two NW–SE-trending faults and located in the inner part of the HasanRobat positive flower strcuture. The Hasan-Robat marbles record a complex shortening and shearing history. This lead to the development of disharmonic ptygmatic folds with vertical to sub-vertical axes and some interference patterns of folding that may have been created from deformations during the Pan-African Orogeny and later phases. Based on this research, tectonic evolution of the Hasan-Robat area is interpreted as the product of three major geotectonic events that have been started after Precambrian to Quaternary: (1) old deformation phases (2) contractional movements and (3) strike-slip movements. Different sets and distributions of joints, faults and folds are confirmed with effect of several deformational stages of the area and formation of the flower structure. 相似文献
Geotechnical and Geological Engineering - Soil-geosynthetic interface behavior under cyclic loading will differ from that under static loading. To this end, a series of static and multistep tests... 相似文献
Characterization of karst systems and forecast of their state variables are essential for groundwater management and engineering in karst regions. These objectives can be met by the use of process-based discrete-continuum models (DCMs). However, results of DCMs may suffer from inversion nonuniqueness. It has been demonstrated that the joint inversion of observations regulated by different natural processes can tackle the nonuniqueness issue in groundwater modeling. However, this has not been tested for DCMs thus far. This research proposes a methodology for the joint inversion of hydro-thermo-chemo-graphs, applying to two small-scale sink-to-spring experiments at Freiheit Spring, Minnesota, USA. In order to address conceptual uncertainty, a multimodel approach was implemented, featuring seven mutually exclusive variants. Spring hydro-thermo-chemo-graphs, for all the variants simulated by MODFLOW-CFPv2, were jointly inverted using a weighted least squares algorithm. Subsequently, models were compared in terms of inversion and forecast performances, as well as parameter uncertainties. Results reveal the suitability of the DCM approach for simultaneous inversion and forecast of hydro-physico-chemical behavior of karst systems, even at a scale of meters and seconds. The estimated volume of the tracer conduit passage ranges from approximately 46–51 m3, which is comparable to the estimate from the flood-pulse method. Moreover, it was demonstrated that the thermograph and hydrograph contain more information about aquifer characteristics than the chemograph. However, this finding can be site-specific and should depend on the analysis scale, the considered conceptual models, and the hydrological state, which are potentially affected by minor unaccountable processes and features.