Delineation of groundwater potential zones in Wadi Saida Watershed of NW-Algeria using remote sensing,geographic information system-based AHP techniques and geostatistical analysis

Sustainable management of groundwater resources has now become an obligation,especially in arid and semi-arid regions given the socio-economic importance of this resource.The optimization in zoning for groundwater exploitation helps in planning and managing groundwater supply works such as boreholes and wells in the catchment.The objective of this study is to use remote sensing and GIS-based Analytical Hierarchy Process(AHP)techniques to evaluate the groundwater potential of Wadi Saida Watershed.Spatial analysis such as geostatistics was also used to validate results and ensure more accuracy.Through the GIS tools and remote sensing technique,earth observation data were converted into thematic layers such as lineament density,geology,drainage density,slope,land use and rainfall,which were combined to delineate groundwater potential zones.Based on their respective impact on groundwater potential,the AHP approach was adopted to assign weights on multi-influencing factors.These results will enable decision-makers to optimize hydrogeological exploration in large-scale catchment areas and map areas.According to the results,the southern part of the Wadi Saida Watershed is characterized as a higher groundwater potential area,where 32%of the total surface area falls in the excellent and good class of groundwater potential.The validation process revealed a 71%agreement between the estimated and actual yield of the existing boreholes in the study area.     

Effects of nitrogen nutritional stress on the morphological and yield parameters of tomato (Solanum lycopersicum L.)

This investigation was carried out to better understand the effects of nitrogen stress on the growth and yield of tomato(Solanum lycopersicon L.). Seeds of S. lycopersicon(Ife No. 1 variety) were collected from the Osun–State Ministry of Agriculture, Oshogbo, Nigeria and planted in analyzed top soil. The plants were grown for a period of five weeks within which they were supplied with water and kept under optimum environmental conditions that enhanced normal growth. After this period, the plants were subjected to different levels of nitrogen stress which include: plants supplied with distilled water only(n), plants supplied with complete nutrient solution(N), plants supplied with nutrient solution in which nitrogen concentration sources was increased by a factor of 5(N5), and plants supplied with nutrient solution in which nitrogen concentration sources was increased by a factor of 10(N10). Analysis of Variance(ANOVA) results shows that there is no significant effect of stress on the growth and morphological parameters of tomato plants. However, there was a significant effect of nitrogen stress on the yield parameters. Nitrogen stress also caused an increase in the number and size of fruits produced in plants subjected with high nitrogen concentration.     

http://www.sciencedirect.com/science/article/pii/S1674987113000546

In the eastern part of the Indian shield,late PaleozoiceMesozoic sedimentary rocks of the Talchir Basin lie precisely along a contact of Neoproterozoic age between granulites of the Eastern Ghats Mobile Belt(EGMB)and amphibolite facies rocks of the Rengali Province.At present,the northern part of the basin experiences periodic seismicity by reactivation of faults located both within the basin,and in the Rengali Province to the north.Detailed gravity data collected across the basin show that Bouguer anomalies decrease from the EGMB(wt15 mGal),through the basin(w 10 mGal),into the Rengali Province(w 15 mGal).The data are consistent with the reportedly uncompensated nature of the EGMB,and indicate that the crust below the Rengali Province has a cratonic gravity signature.The contact between the two domains with distinct sub-surface structure,inferred from gravity data,coincides with the North Orissa Boundary Fault(NOBF)that defnes the northern boundary of the Talchir Basin.Post-Gondwana faults are also localized along the northern margin of the basin,and present-day seismic tremors also have epicenters close to the NOBF.This indicates that the NOBF was formed by reactivation of a Neoproterozoic terrane boundary,and continues to be susceptible to seismic activity even at the present-day.     

http://www.sciencedirect.com/science/article/pii/S167498711300114X

正The Precambrian shields and associated suture zones of the globe preserve important records of continental growth and destruction,the formation and closure of ocean basins,and the early evolution of the Earth in terms of tectonics,resources,and environment.They also offer critical clues on the nature and style     

Serpentinized Peridotites at the North Part of the Wadi Allaqi District (Egypt): Implications for the Tectono-Magmatic Evolution of Fore-arc Crust

The Neoproterozoic Allaqi-Heiani suture （800-700 Ma） in the south Eastern Desert of Egypt is the northernmost linear ophiolitic belt that defines an arc-arc suture in the Arabian- Nubian shield （ANS）. The Neoproterozoic serpentinized peridotites represent a distinct lithology of dismembered ophiolites along the Allaqi-Heiani suture zone. The alteration of peridotites varies, some contain relicts of primary minerals （Cr-spinel and olivine） and others are extremely altered, especially along thrusts and shear zones, with development of talc, talc-carbonate and quartz-carbonate. The fresh cores of the chromian spinels are rimmed by ferritchromite and Cr- magnetite. The fresh chromian spinels have high Cr# （0.62 to 0.79）, while Mg# shows wider variation （0.35-0.59）. High Cr# in the relict chromian spinels and Fo content in the primary olivines indicate that they are residual peridotites after extensive partial melting. The studied ophiolitic upper mantle peridotites are highly depleted and most probably underwent high degrees of partial melting at a supra-subduction zone setting. They can be produced by up to -20%-22% dynamic melting of a primitive mantle source. The mineralogical and geochemical features of the studied rocks reflect that the mantle peridotites of the north part of the Wadi Allaqi district are similar to the fore-arc peridotites of a supra-subduction zone.     

Concentrations of organochlorines in sperm whales (Physeter macrocephalus) from Southern Australian waters

Concentrations of DDTs, PCBs and HCHs were measured in sperm whales involved in two mass stranding events on the west coast of Tasmania, Australia in February 1998. DDTs and PCBs were present in all samples analysed, while only three contained HCHs. The relationships between organochlorines, sex, age and reproductive groups were marked by high variability. Differences in organochlorine concentrations were observed between animals from the two stranding sites and discussed in light of the ecology of this species. Concentrations of all pollutants were stratified throughout the vertical aspect of the blubber and possible reasons for and the implications of this are discussed. Concentrations of compounds were higher than those documented in this species in the Southern Hemisphere previously, although were relatively lower than those documented in the Northern Hemisphere. However, comparisons were confounded by spatial and temporal differences. Continued monitoring of marine mammals throughout this region in a co-coordinated, standardized manner is essential for establishing definite temporal and spatial variations in pollutant concentrations.     

Pushover analysis of reinforced concrete frames considering shear failure at beam-column joints

Since most current seismic capacity evaluations of reinforced concrete(RC) frame structures are implemented by either static pushover analysis(PA) or dynamic time history analysis,with diverse settings of the plastic hinges(PHs) on such main structural components as columns,beams and walls,the complex behavior of shear failure at beam-column joints(BCJs) during major earthquakes is commonly neglected.This study proposes new nonlinear PA procedures that consider shear failure at BCJs and seek to assess the actual damage to RC structures.Based on the specifications of FEMA-356,a simplified joint model composed of two nonlinear cross struts placed diagonally over the location of the plastic hinge is established,allowing a sophisticated PA to be performed.To verify the validity of this method,the analytical results for the capacity curves and the failure mechanism derived from three different full-size RC frames are compared with the experimental measurements.By considering shear failure at BCJs,the proposed nonlinear analytical procedures can be used to estimate the structural behavior of RC frames,including seismic capacity and the progressive failure sequence of joints,in a precise and effective manner.     

http://www.sciencedirect.com/science/article/pii/S1674987112000084

Seismic anisotropy and its main features along the convergent boundary between Africa and Iberia are detected through the analysis of teleseismic shear-wave splitting.Waveform data generated by 95 teleseismic events recorded at 17 broadband stations deployed in the western Mediterranean region are used in the present study.Although the station coverage is not uniform in the Iberian Peninsula and northwest Africa,significant variations in the fast polarization directions and delay times are observed at stations located at different tectonic domains.Fast polarization directions are oriented predominantly NW-SE at most stations which are close to the plate boundary and in central Iberia;being consistent with the absolute plate motion in the region.In the northern part of the Iberian Peninsula,fast velocity directions are oriented nearly E—W;coincident with previous results.Few stations located slightly north of the plate boundary and to the southeast of Iberia show E—W to NE-SW fast velocity directions,which may be related to the Alpine Orogeny and the extension direction in Iberia.Delay times vary significantly between 0.2 and 1.9 s for individual measurements,reflecting a highly anisotropic structure beneath the recording stations.The relative motion between Africa and Iberia represents the main reason for the observed NW-SE orientations of the fast velocity directions.However,different causes of anisotropy have also to be considered to explain the wide range of the splitting pattern observed in the western Mediterranean region.Many geophysical observations such as the low Pn velocity,lower lithospheric Q values,higher heat flow and the presence of high conductive features support the mantle How in the western Mediterranean,which may contribute and even modify the splitting pattern beneath the studied region.     

加拉帕戈斯三联点北部岩石层的开裂

加拉帕戈斯三联点是由科科斯板块、纳斯卡板块和太平洋板块在加拉帕戈斯微板块处汇聚形成的脊-脊-脊型三向连接构造。在科科斯—纳斯卡裂谷的大部分内斜坡以北区域,长约250km、宽约50km的西北—东南向的火山岩裂谷横插在东太平洋海隆的南北向海山上。在过去的4百万年中,东北—西南向的东太平洋海隆为一系列的较小裂谷提供了条件,使得那些小裂谷通常与东太平洋海隆共同形成三联点,而且与正在扩张的科科斯—纳斯卡裂谷有50～100km的距离。本文假设该裂谷的位置是由压力控制的,并且压力与占主导作用的科科斯—纳斯卡裂谷相关,随着与东太平洋海隆的距离增大而增大。我们推测,在科科斯—纳斯卡裂谷的南侧也曾有类似的短暂性的裂谷发生,并且曾有助于旋转的加拉帕戈斯微板块的初期形成(大约是1.5百万年)。     

化学方法改良吹填土固结沉降性质研究

大连市大窑湾港区的吹填土为高分散性低液限粉质黏土,其特点是亲水性高,含水量大,排水率低,这造成了吹填土承载力低,在荷载作用下变形量大,在很长一段时间内无法作为正常建筑地基使用.通过在盐水环境下添加不同剂量的浓度为0.1%的絮凝剂Praestol-2515或Praestol-650溶液,可以观察到土颗粒迅速聚合,土粒粒径明显增大,粒间胶结更加均匀和紧密,形成絮状物,从而促进了土颗粒与自由水分的分离,导致过饱和吹填土（悬浊液）沉降速度大大提高,极大地缩短了吹填土的排水固结时间,在短期内达到建筑地基所需要的变形量和承载能力.研究结果对于沿海地区过饱和吹填土的造陆工程,以及类似的高含水率黏性土的地基处理具有重要的启示意义.