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121.
We analyze and integrate energy andforestry carbon mitigation scenarios for Mexicobetween the year 1994 and 2010. The energy optionsrange from efficient end-use technologies to renewabletechnologies for electricity generation. Forestryoptions include avoiding deforestation through themanagement of native forests, and two afforestationoptions: restoration plantations and agroforestrysystems. The methodology utilized to evaluatedifferent energy and forestry scenarios is based on a`bottom up' model. In the year 2010, total carbonemissions will reach 879 Tg of CO2, of which 83%comes from energy consumption. The total carbonmitigation potential reaches 348 Tg of CO2 by2010, 62% of which comes from forestry options.Mitigation costs range from $–45.9/ton CO2 to$106.4/ton CO2. Several options, particularlyconcerning energy technologies, are cost effectivefrom a national perspective. In each sector, differentbarriers can hinder the implementation of mitigationalternatives.  相似文献   
122.
The aim of this study was to transform the rain into flow in the basin of Wadi Djendjen by using a simulation model in absence of the continuous measurements of the flow. The obtained results indicated and confirmed the strong adaptability of this model with varied hydroclimatic situations. The validation process showed an interesting result, which lead to conclude that the model is well calibrated and has a good performance to be used for the basins with Mediterranean climate. The obtained results for the simulation by the GR2M model over the studied period (1973–1986) showed that there no significant difference between the obtained value for the yearly average flow (197.70 hm3) and that measured at Missa hydrometric station (200.80 hm3), which allow us to estimate quantitatively the flow in Missa hydrometric station. While, for the period of 2000–2012, the results showed that the yearly average flow value (171.90 hm3), is significantly different (reduction of 15% for 12 years), in comparison with that measured at Missa hydrometric station (200.80 hm3). This can be due to the dryness which struck the region since 2000, and the local degradation of the forest ecosystem, which has considerably affected the runoff surface.  相似文献   
123.
Siripatana  Adil  Le Maitre  Olivier  Knio  Omar  Dawson  Clint  Hoteit  Ibrahim 《Ocean Dynamics》2020,70(8):1103-1127
Ocean Dynamics - Bayesian inference with coordinate transformations and polynomial chaos for a Gaussian process with a parametrized prior covariance model was introduced in Sraj et al. (Comput...  相似文献   
124.
We examined the diet of juvenile fish of four species – Eucinostomus melanopterus (Gerreidae), Ethmalosa fimbriata (Clupeidae), Monodactylus sebae (Monodactylidae), and Sarotherodon melanotheron (Cichlidae) – between their appearance on the nursery ground and the end of the recruitment season, when they began to shift to deeper parts of the estuary. Fish were collected from the Sine-Saloum, an inverse estuary in Senegal, West Africa. Sampling was conducted at six sites located along the salinity gradient. The study was conducted in the context of an inverse estuary where increasing salinity leads to the disappearance of mangroves.  相似文献   
125.
In this study, we investigated the spatial characteristics of the rate of soil distribution and the mechanism of major element migration in a typical karst hillslope in Guangxi Province, Southwestern China. Soil redistribution was examined using 137Cs technique under different hillslope components. With the combination of geochemical methods, the migration characteristics of major elements in soils of three hillslope components in both the horizontal and vertical directions were determined. Thirty-seven soil samples were collected and analyzed for 137Cs and the major elements were determined. By using the profile distribution model the mean soil redistribution rates were found to be -17.01, 0.40 and -23.30 t ha-1 yr-1 in the summit (BYSD), shoulder (BYSY) and toeslope (BYSJ) components of the studied hillslope, respectively. In comparison to BYSD, the sesquioxides of Fe2O3 and TiO2 tend to be enriched, whereas the alkalis (CaO, MgO, Na2O and K2O) tend to be depleted, both in the shoulder and toeslope components. Due to human and animal activities, the contents of CaO, MgO, K2O and Na2O have somewhat increased within the topsoil. The results indicated that 137Cs activities are significantly correlated with clay particles and organic matter, and are affected by the pedogenic process and vegatation. Overall, it maybe necessary to use techniques such as 137Cs to investigate soil erosion with the combination of geochemical methods.  相似文献   
126.
The E-W trending Atlas System of Maghreb consists of weakly shortened, intra-continental fold belts associated with plateau areas (“Mesetas”), extending between the south-westernmost branch of the Mediterranean Alpine Belt (Rif-Tell) and the Sahara Platform. Although the Atlas system has been erected contemporaneously from Morocco to Algeria and Tunisia during the Middle Eocene to Recent, it displays a conspicuous longitudinal asymmetry, with i) Paleozoic outcrops restricted to its western part; ii) highest elevation occurring in the west, both in the Atlas System and its foreland (Anti-Atlas); iii) low elevation corridors (e.g. Hodna) and depressed foreland (Tunisian Chotts and Sahel area) in the east. We analyse the origin of these striking contrasts in relation with i) the Variscan heritage; ii) crustal vertical movements during the Mesozoic; iii) crustal shortening during the Cenozoic and finally, iv) the occurrence of a Miocene-Quaternary hot mantle anomaly in the west. The Maghreb lithosphere was affected by the Variscan orogeny, and thus thickened only in its western part. During the Late Permian-Triassic, a paleo-high formed in the west between the Central Atlantic and Alpine Tethys rift systems, giving birth to the emergent/poorly subsident West Moroccan Arch. During the late Middle Jurassic-Early Cretaceous, Morocco and western Algeria were dominantly emergent whereas rifting lasted on in eastern Algeria and Tunisia. We ascribe the uplift of the western regions to thermal doming, consistent with the Late Jurassic and Barremian gabbroic magmatism observed there. After the widespread transgression of the high stand Cenomanian-Turonian seas, the inversion of the Atlas System began during the Senonian as a consequence of the Africa-Eurasia convergence. Erosion affected three ENE-trending uplifted areas of NW Africa, which we consider as lithospheric anticlines related to the incipient Africa-Europe convergence. In contrast, in eastern Algeria and Tunisia a NW-trending rift system developed contemporaneously (Sirt rifting), normal to the general trend of the Atlas System. The general inversion and orogenesis of the Atlas System occurred during two distinct episodes, Middle-Late Eocene-Oligocene and Late Miocene-Pliocene, respectively, whereas during the intervening period, the Africa-Europe convergence was mainly accommodated in the Rif-Tell system. Inversion tectonics and crustal thickening may account for the moderate uplift of the eastern Atlas System, not for the high elevation of the western mountain ranges (Middle Atlas, High Atlas, Anti-Atlas). In line with previous authors, we ascribe part of the recent uplift of the latter regions to the occurrence of a NE-trending, high-temperature mantle anomaly, here labelled the Moroccan Hot Line (MHL), which is also marked by a strip of late Miocene-Quaternary alkaline magmatism and significant seismicity.  相似文献   
127.
Lining contact pressure and ground deformation of Raghadan transportation tunnel (Amman, Jordan) were investigated. The tunnel is 1.1 km in length and 13.5 m in diameter. This study was intended to integrate useful relations among the widely used rock classification system (RMR: rock mass rating), Hoek–Brown classification, and lining-ground interaction. The materials encountered along the tunnel alignment were limestone, dolomatic limestone, marly limestone, dolomite, and sillicified limestone. The ground conditions along the tunnel alignment including bedding planes, joint sets and joint conditions, rock quality, water flow, and rock strength were evaluated based on the drilled boreholes and rock exposures. Elasto-plastic finite element analyses were conducted to study the effect of rock mass conditions and tunnel face advance on the behavior of lining-ground interaction. The results of the analyses showed that lining contact pressure decreases linearly with the increase in RMR value. Also the results showed that tunnel lining contact pressure and crown inward displacement decreases with the increase in the unsupported distance (distance between tunnel face and the end of the erected lining). Ground displacement above the tunnel crown was found to be increases in an increasing rate with the decrease in the depth above the crown. This displacement was also found to be affected by the RMR value and the unsupported distance.  相似文献   
128.
Existing unreinforced masonry buildings frequently suffer out-of-plane local collapse mechanisms when undergoing earthquake ground motion. The energy damping that occurs during the motion, due to impacts of a wall against the foundation or against other walls, is a relevant parameter on the response. An experimental investigation has been carried out to estimate the dissipation of kinetic energy that takes place during free oscillations. Restraint conditions allow for two-sided rocking (wall resting on a foundation) and one-sided rocking (wall resting on a foundation adjacent to transverse walls). Five specimens have been tested, modelling walls acted out-of-plane (fa?ades). When one-sided rocking is under consideration, different depths of the contact surface between fa?ade and transverse walls are considered. In the case of two-sided rocking, the experimental coefficient of restitution is slightly lower than the analytic coefficient. In the case of one-sided rocking, an analytic formulation is proposed and this is compared against experimental data. Although the coefficient of restitution of one-sided rocking is less than half that of two-sided rocking, it is not equal to zero. Thus, it cannot induce a sudden stop of the motion. Hence, nonlinear time history analyses performed under this assumption may prove unsafe. Moreover, a comparison has been carried out between overturning maps, induced by twenty natural accelerograms, computed for the analytic coefficient of restitution and those computed for the experimental coefficient of restitution. The increased energy dissipation reduces the frequency of overturning and causes a more regular behaviour.  相似文献   
129.
The geochemistry, mineralogy, and grain size distribution of several estuarine cohesive sediment samples from potentially human-influenced areas without such an influence were analyzed to determine the natural heavy metal content and evaluate its impact on the Bahía Blanca estuarine environment. The data were compared with different ranges of concentrations for heavy metals in marine sediments established by the NOAA Screening Quick Reference Tables in which values range from background levels to those considered toxic to the marine environment. Our total heavy metal contents were below the established hazardous levels in all the analyzed samples, even though the potentially human-influenced areas (harbors, industry, urban spread) showed the highest total concentration values as well as greater percentages of bioavailable compounds. This would imply a low and not extensive anthropogenic input into the environment. The relatively high proportions in which Cd, Pb, and Cr appear as bioavailable compounds at some sites not influenced by human activity suggest the presence of a natural source for these elements. This could be attributed to the weathering of naturally occurring volcanic minerals, indicating that special care must be taken when monitoring of sediment for anthropogenic activity is carried out within this environment. According to the results obtained, and in order to minimize the environmental impact caused by periodic water injection dredging, relocation of sewage outfalls from vessel mooring areas into open waters is strongly recommended.  相似文献   
130.
This work was done on the representative section (230 cm) in Dora site which located in Baghdad in the central of the Mesopotamian Plain. Eleven soil samples were examined mineralogically and palynologically. Grain size analyses showed that silt is the higher fraction (61%), clay is the least (9%), whereas sand forms 30%. Translucent and opaque heavy minerals contributed 57% from the sand fraction, whereas the light minerals formed just 43%. The type of heavy minerals and its maturity defined four provenances—they are granitic, basic igneous and metamorphic rocks—that belong to the high lands of south Turkey and north of Iraq. The fourth provenance is the sedimentary rocks which are located north of Mesopotamian Plain around the Tigris River and their tributaries. Dinoflagellate within thin bed of marine origin clearly indicated the transgression of the Arabian Sea northward through Tigris and Euphrates valleys or high marine waves reached to Baghdad before 10,000 years P.B. approximately. This means that the marine sediments were also an additional source of the Mesopotamian Plain. Three specific climatic features are identified via palynological interpretation; a temperate-wet climate extended from 10,000 to 5,000 years P.B. followed by dry period extended from 5,000 to 3,500 years P.B. and the last climatic feature is characterized by oscillation of wet to dry periods which is dominant since 3,500 till now.  相似文献   
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