A coupled 1D-2D hydrodynamic model, MIKE FLOOD was used to simulate the flood inundation extent and flooding depth in the
delta region of Mahanadi River basin in India. Initially, the 1D model MIKE 11 was calibrated using river water level and
discharge data of various gauging sites for the monsoon period (June to October) of the year 2002. Subsequently, the calibrated
set up was validated using both discharge and water level data for the same period of the year 2001. The performance of calibration
and validation results of MIKE 11 were evaluated using different performance indices. A bathymetry of the study area with
a spatial resolution of 90m was prepared from SRTM DEM and provided as an input to the 2D model, MIKE 21. MIKE 11 and MIKE
21 models were then coupled using lateral links to form the MIKE FLOOD model set up for simulating the two dimensional flood
inundations in the study area. Flood inundation is simulated for the year 2001 and the maximum flood inundation extent simulated
by the model was compared with the corresponding actual inundated area obtained from IRS-1D WiFS image. 相似文献
The provision of urban service and citizens’ satisfaction is an important key issue in urban planning. Importance-performance analysis (IPA) is an effective and widely applicable technique to explore consumer’s satisfaction. IPA helps to prioritize the management strategies for urban services using the IPA. Purpose of the present study is to assess the performance of urban services and citizen’s satisfaction level of Panskura municipality using IPA models and improvement index. A total of 629 valid household responses are collected with the help of the door-to-door primary survey technique. The study reveals that all the selected seven urban services have significant importance-performance gap except water supply. Residents of the Panskura municipality are very much satisfied with the water supply service because of the very minimum improvement score. The combined result of IPA matrices and improvement index suggests residents are dissatisfied to a great extent with the performance of four urban services, i.e. health, economy, transportation and sanitation. These urban services require a problem-solving urgent action for restoration of the performance status. The improvement and prioritization of urban service are also required to fulfil the demand of target groups.
In this paper we study the variation of Vp/Vs and Poisson's ratio (δ) in the Yellowstone National Park region, using earthquakes which were well recorded by a local seismic network. We find that the average Vp/Vs value within the geothermally active Yellowstone caldera is about 7% lower than in the area outside the caldera. Within the caldera itself there may be a further 2–7% reduction of Vp/Vs in the hydrothermally active Norris Geyser Basin, the Upper and Lower Geyser Basins, and the Yellowstone Lake and Mud Volcano regions. After considering various possible causes for Vp/Vs changes, such as geologic and structural differences, thermal effects, partial melting, and hydrothermal activity, we conclude that the most plausible explanation for the observed Vp/Vs reduction is the presence of hot-water at temperatures and pore-pressures near the water steam transition in the caldera geothermal reservoirs. 相似文献
Three Al-Cr exchange isotherms at 1,250°, 1,050°, and 796° between Mg(Al, Cr)2O4 spinel and (Al, Cr)2O3 corundum crystalline solutions have been studied experimentally at 25 kbar pressure. Starting from gels of suitable bulk
compositions, close approach to equilibrium has been demonstrated in each case by time studies.
Using the equation of state for (Al, Cr)2O3 crystalline solution (Chatterjee et al. 1982a) and assuming that the Mg(Al, Cr)2O4 can be treated in terms of the asymmetric Margules relation, the exchange isotherms were solved for Δ G*,
and
. The best constrained data set from the 1,250° C isotherm clearly shows that the latter two quantities do not overlap within
three standard deviations, justifying the choice of asymmetric Margules relation for describing the excess mixing properties
of Mg(Al, Cr)2O4 spinels. Based on these experiments, the following polybaric-polythermal equation of state can be formulated:
, P expressed in bars, T in K, G
mex
and W
G,iSp
in joules/mol.
Temperature-dependence of G
mex
is best constrained in the range 796–1,250° C; extrapolation beyond that range would have to be done with caution. Such extrapolation
to lower temperature shows tentatively that at 1 bar pressure the critical temperature, Tc, of the spinel solvus is 427° C, with dTc/dP≈1.3 K/kbar. The critical composition, Xc, is 0.42
, and changes barely with pressure.
Substantial error in calculated phase diagrams will result if the significant positive deviation from ideality is ignored
for Al-Cr mixing in such spinels. 相似文献
The technique of linear parametric programming has been applied to derive sets of internally consistent thermodynamic data for 21 condensed phases of the quaternary system CaO-Al2O3-SiO2-H2O (CASH) (Table 4). This was achieved by simultaneously processing:
calorimetric data for 16 of these phases (Table 1), and
experimental phase equilibria reversal brackets for 27 reactions (Table 3) involving these phases.
Calculation of equilibrium P-T curves of several arbitrarily picked reactions employing the preferred set of internally consistent thermodynamic data from Table 4 shows that the input brackets are invariably satisfied by the calculations (Fig. 2a). By contrast, the same equilibria calculated on the basis of a set of thermodynamic data derived by applying statistical methods to a large body of comparable input data (Haas et al. 1981; Hemingway et al. 1982) do not necessarily agree with the experimental reversal brackets. Prediction of some experimentally investigated phase relations not included into the linear programming input database also appears to be remarkably successful. Indications are, therefore, that the thermodynamic data listed in Table 4 may be used with confidence to predict geologic phase relations in the CASH system with considerable accuracy. For such calculated phase diagrams and their petrological implications, the reader's attention is drawn to the paper by Chatterjee et al. (1984). 相似文献
Ephesite, Na(LiAl2) [Al2Si2O10] (OH)2, has been synthesized for the first time by hydrothermal treatment of a gel of requisite composition at 300≦T(° C)≦700 and \(P_{H_2 O}\) upto 35 kbar. At \(P_{H_2 O}\) between 7 and 35 kbar and above 500° C, only the 2M1 polytype is obtained. At lower temperatures and pressures, the 1M polytype crystallizes first, which then inverts to the 2M1 polytype with increasing run duration. The X-ray diffraction patterns of the 1M and 2M1 poly types can be indexed unambiguously on the basis of the space groups C2 and Cc, respectively. At its upper thermal stability limit, 2M1 ephesite decomposes according to the reaction (1) $$\begin{gathered} {\text{Na(LiAl}}_{\text{2}} {\text{) [Al}}_{\text{2}} {\text{Si}}_{\text{2}} {\text{O}}_{{\text{10}}} {\text{] (OH)}}_{\text{2}} \hfill \\ {\text{ephesite}} \hfill \\ {\text{ = Na[AlSiO}}_{\text{4}} {\text{] + LiAl[SiO}}_{\text{4}} {\text{] + }}\alpha {\text{ - Al}}_{\text{2}} {\text{O}}_{\text{3}} {\text{ + H}}_{\text{2}} {\text{O}} \hfill \\ {\text{nepheline }}\alpha {\text{ - eucryptite corundum}} \hfill \\ \end{gathered}$$ Five reversal brackets for (1) have been established experimentally in the temperature range 590–750° C, at \(P_{H_2 O}\) between 400 and 2500 bars. The equilibrium constant, K, for this reaction may be expressed as (2) $$log K{\text{ = }}log f_{{\text{H}}_{\text{2}} O}^* = 7.5217 - 4388/T + 0.0234 (P - 1)T$$ where \(f_{H_2 O}^* = f_{H_2 O} (P,T)/f_{H_2 O}^0\) (1,T), with T given in degrees K, and P in bars. Combining these experimental data with known thermodynamic properties of the decomposition products in (1), the following standard state (1 bar, 298.15 K) thermodynamic data for ephesite were calculated: Hf,298.150=-6237372 J/mol, S298.150=300.455 J/K·mol, G298.150=-5851994 J/mol, and V298.150=13.1468 J/bar·mol. 相似文献
Uranium and tin occurrences in the South Mountain Batholith are preferentially found in or near a para-intrusive rock suite which is characterized by strong granophile element enrichments. Furthermore, bodies which show a Th-enrichment trend with increasing differentiation appear to be more favorable exploration targets than spatially associated bodies in which Th is depleted. 相似文献
Internally consistent thermodynamic datasets available at present call for a further improvement of the data for nepheline
(Holland and Powell 1988; Berman 1991). Because nepheline is a common rock-forming mineral, an attempt has been made to improve
on the present state of knowledge of its thermodynamic properties. To achieve that goal, two heterogeneous reactions involving
nepheline, albite, jadeite and a-quartz in the system NaAlSiO4-SiO2 have been reversed bylong duration runs in the range 460 ≤ T(°C) ≤ 960 and 10 ≤ P(kbar) ≤ 22. Given sufficiently long run times, thealbite run products approach internal equilibrium with respect to their Al,Si order-disorder states. Using appropriate thermochemical, thermophysical, and volumetric data,
Landau expansion for albite, and the relevant reaction reversals, a refined thermodynamic dataset (ΔfHi0 and Si0) has been derived for nepheline, jadeite, a-quartz, albite, and monalbite. Our refined data agree very well with theircalorimetric counterparts, but have smaller uncertainties. The refined dataset for ΔfHi0 and Si0, including their uncertainties and correlation, help generate the NaAlSiO4-SiO2 phase diagram including 2a confidence interval for eachP-T curve (Fig. 5).
Editorial responsibility: W. Schreyer 相似文献