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121.
The Hammam Lif coast (North-East of Tunisia) suffered from erosion mainly after the storm that damaged the zone in 1981. To protect it, eight shore-parallel breakwaters were built. The present study is interested in presenting the effect of the protection works on the coastline behavior by using aerial photographs geo-referenced by the digital photogrammetric method and empirical relationships. The successive breakwaters made a general accretion with formation of seven tombolos and salient. The response of the coast to these structures was related to the characteristics of these latter (length, distance to coast, and spacing). The effectiveness of such protection works is shown by the evaluation of the accretion areas formed behind them. The breakwaters which are the longest, less distant from the shoreline, and less spaced formed well-developed tombolos. Whereas, the structures which are short, very far from the coastline, and far from each other caused very small tombolos and even a salient. 相似文献
122.
Annual and seasonal trends of cooling, heating, and industrial degree-days in coastal regions of Saudi Arabia 总被引:1,自引:0,他引:1
Shafiqur Rehman Luai M. Al-Hadhrami Shamsuddin Khan 《Theoretical and Applied Climatology》2011,103(3-4):479-488
In this study, we systematically analyze the changing properties of reference evapotranspiration (ETref) across China using Penman?CMonteith (P-M) method, exploring the major sensitive meteorological variables for ETref, and investigating influences of human activities, mainly urbanization in this study, on ETref changes in both space and time. We obtain some important conclusions: (1) decreasing annual and seasonal ETref is observed in the east, south and northwest China. However, a long strip lying between these regions is identified to be characterized by increasing ETref; (2) in the regions east to 100°E, the net total solar radiation is the main cause behind the decreasing ETref. In northwest China, however, relative humidity is recognized as the most sensitive variable for the ETref; (3) in the east and south China, urbanization greatly influences the ETref by directly decreasing net solar radiation. The increased air pollution and aerosols in the highly urbanized regions are the main driving factors causing decreasing net radiation; and (4) this study reveals accelerating hydrological cycle from south to north China. Besides, increasing ETref in the source regions of large rivers in China may pose new challenges for the basin-scale water resource management. The results of this study highlight the integrated effects of climate changes and human activities on ETref changes in different regions of China, which will be of great scientific and practical merits in in-depth understanding of hydrological cycle alterations under the changing environment in China. 相似文献
123.
The activities of 210Po and 210Pb were determined in commonly consumed seafoods to evaluate the internal exposure and risk to humans residing Kudankulam coast where a mega nuclear power plant is under construction. The concentration of 210Po in seafoods ranged from 1.2 ± 0.7 to 248 ± 8.1 Bq kg−1. Meanwhile, 210Pb ranged between 1.1 ± 0.05 and 14.8 ± 1.6 Bq kg−1. The committed effective dose (CED) due to 210Po and 210Pb varied from 11.04 to 515.6 and 3.93 to 23.5 μSv yr−1, respectively. The lifetime cancer risk for the public due to 210Po was in the range of 3.47 × 10−5-1.62 × 10−3 and it was 4.03 × 10−5-1.96 × 10−4 due to 210Pb. The activity intake, effective dose and cancer risk was found lesser than international guidelines and the seafood intake was considered to be safe for human consumption. 相似文献
124.
Mohamed Chiban Amina Soudani Fouad Sinan Saida Tahrouch Michel Persin 《洁净——土壤、空气、水》2011,39(4):376-383
Low cost adsorbents were prepared from dried plants for the removal of heavy metals, nitrate, and phosphate ions from industrial wastewaters. The efficiency of these adsorbents was investigated using batch adsorption technique at room temperature. The dried plant particles were characterized by N2 at 77 K adsorption, scanning electron microscopy, energy dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, and phytochemical screening. The adsorption experiments showed that the microparticles of the dried plants presented a good adsorption of heavy metals, phosphate, and nitrate ions from real wastewaters. This adsorption increased with increasing contact time. The equilibrium time was found to be 30 min for heavy metals and nitrate ions and 240 min for phosphate ions. After the adsorption process, the Pb(II) concentrations, as well as those of Cd(II), Cu(II), and Zn(II) were below the European drinking water norms concentrations. The percentage removal of heavy metals, nitrates, and phosphates from industrial wastewaters by dried plants was ~94% for Cd2+, ~92% for Cu2+, ~99% for Pb2+, ~97% for Zn2+, ~100% for ${\rm NO}_{{\rm 3}}^{{-} } $ and ~77% for ${\rm PO}_{{\rm 4}}^{3{-} } $ ions. It is proved that dried plants can be one alternative source for low cost absorbents to remove heavy metals, nitrate, and phosphate ions from municipal and industrial wastewaters. 相似文献
125.
A. Yu. Bundel V. N. Kryzhov Young-Mi Min V. M. Khan R. M. Vilfand V. A. Tishchenko 《Russian Meteorology and Hydrology》2011,36(3):145-154
The probability multimodel forecast system based on the Asia-Pacific Economic Cooperation Climate Center (APCC) model data is verified. The winter and summer seasonal mean fields T 850 and precipitation seasonal totals are estimated. To combine the models into a multimodel ensemble, the probability forecast is calculated for each of single models first, and then these forecasts are combined using the total probability formula. It is shown that the multimodel forecast is considerably more skilful than the single-model forecasts. The forecast quality is higher in the tropics compared to the mid- and high latitudes. The multimodel ensemble temperature forecasts outperform the random and climate forecasts for Northern Eurasia in the above- and below-normal categories. Precipitation forecast is less successful. For winter, the combination of single-model ensembles provides the precipitation forecast skill exceeding that of the random forecast for both Northern Eurasia and European Russia. 相似文献
126.
Prosanta Kumar Khan 《International Journal of Earth Sciences》2011,100(7):1749-1758
Present study addresses the role of major plate-driving forces, particularly the slab pull and slab resistive forces, for
the generation of 26 December 2004 M
w > 9.0 off Sumatra megathrust earthquake. Major controls on the plate-driving forces are normally visualized through age,
speed, and average dip of the slab during subduction. Wide variation in age, plate obliquity, stress obliquity, subduction
rate, dip angle, and flexing depth of the subducting oceanic lithosphere between Andaman and Sumatra thus allowed us for quantitative
evaluation of the slab pull (F
SP) and slab resistive (F
SR) forces in three well-defined sectors (I, II and III). Computed values of these forces in the three sectors: (1) F
SP = 1.29 × 1013 N/m, F
SR = 1.41 × 1013 N/m; sector I, (2) F
SP = 2.10 × 1013 N/m, F
SR = 1.13 × 1013 N/m; sector II, and (3) F
SP = 2.08 × 1013 N/m, F
SR = 2.72 × 1013 N/m; sector III clearly suggest a spatial variation of stress regime in the subducting oceanic lithosphere. Excess F
SR in sectors I and III are interpreted as the causative forces behind the triggering of major seismic energy bursts near Sumatra
and Andaman on 26 December 2004. A gap of minimum seismic energy burst near Great Nicobar possibly was controlled by the excess
of F
SP in sector II. This study further advocates that the cyclic stress, resulted from unbalanced component of slab resistive force,
had a definite control on the occurrence of 2004 off Sumatra megathrust earthquake around the flexing zone of the subducting
lithosphere. 相似文献
127.
For mineral resource assessment, techniques based on fuzzy logic are attractive because they are capable of incorporating uncertainty associated with measured variables and can also quantify the uncertainty of the estimated grade, tonnage etc. The fuzzy grade estimation model is independent of the distribution of data, avoiding assumptions and constraints made during advanced geostatistical simulation, e.g., the turning bands method. Initially, fuzzy modelling classifies the data using all the component variables in the data set. We adopt a novel approach by taking into account the spatial irregularity of mineralisation patterns using the Gustafson–Kessel classification algorithm. The uncertainty at the point of estimation was derived through antecedent memberships in the input space (i.e., spatial coordinates) and transformed onto the output space (i.e., grades) through consequent membership at the point of estimation. Rather than probabilistic confidence intervals, this uncertainty was expressed in terms of fuzzy memberships, which indicated the occurrence of mixtures of different mineralogical phases at the point of estimation. Data from different sources (other than grades) could also be utilised during estimation. Application of the proposed technique on a real data set gave results that were comparable to those obtained from a turning bands simulation. 相似文献
128.
GIS-based impact assessment of land-use changes on groundwater quality: study from a rapidly urbanizing region of South India 总被引:4,自引:0,他引:4
Haris H. Khan Arina Khan Shakeel Ahmed Jerome Perrin 《Environmental Earth Sciences》2011,63(6):1289-1302
This study attempts to assess the influence of changing land-use patterns on the groundwater quality of the hard rock aquifer
system in the Maheshwaram watershed, near Hyderabad, India. The study area is a rapidly urbanizing region with land development
progressing at a fast pace. To study the impact of this rapid urbanization and overall land-use transition, a groundwater
quality index (GQI) was prepared within a geographical information system (GIS). The GQI integrates the different water quality
parameters to give a final index value that can be used for spatio-temporal comparisons. The land-use transitions were closely
monitored from 2003 to 2008 using multispectral satellite images. The land-use pattern has changed drastically with an increase
in the built-up area at the expense of other land uses. The analysis reveals a rapid deterioration of groundwater quality
related mainly to the increase in built-up land with unsewered sanitation and poultry farms. Seasonal variability of the groundwater
quality was also assessed. Mean GQI decreased from 84.16 to 83.26 over a period of 5 years from 2003 to 2008, while seasonal
variability of water quality increased. GQI and Seasonal Variability of water quality were integrated in GIS to yield a groundwater
sustainability map, in terms of water quality. Zones of sustainable and unsustainable groundwater use were demarcated for
better decision making related to municipal land allotment in this rapidly urbanizing region. 相似文献
129.
Sarat Kumar Das Pijush Samui Shakilu Zama Khan Nagarathnam Sivakugan 《Central European Journal of Geosciences》2011,3(4):449-461
Stability with first time or reactivated landslides depends upon the residual shear strength of soil. This paper describes prediction of the residual strength of soil based on index properties using two machine learning techniques. Different Artificial Neural Network (ANN) models and Support Vector Machine (SVM) techniques have been used. SVM aims at minimizing a bound on the generalization error of a model rather than at minimizing the error on the training data only. The ANN models along with their generalizations capabilities are presented here for comparisons. This study also highlights the capability of SVM model over ANN models for the prediction of the residual strength of soil. Based on different statistical parameters, the SVM model is found to be better than the developed ANN models. A model equation has been developed for prediction of the residual strength based on the SVM for practicing geotechnical engineers. Sensitivity analyses have been also performed to investigate the effects of different index properties on the residual strength of soil. 相似文献
130.
We study the phase transition in a gravitating system by analyzing grand canonical partition function as a function of complex fugacity. We extend the Yang-Lee theory to study phase transitions in the gravitational galaxy clustering of galaxies having a variety of masses. This generalizes our previous work based on the same theory for the single-component system to a multicomponent system. We find that galaxy clustering is sensitive to masses and number densities of individual galaxies at early stages while at later stages collective behavior of the particles is more pronounced. This validates our earlier work obtained from different considerations. 相似文献