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51.
Moussa Dia Rachid Zentar Nor-edine Abriak Ange Nzihou Guy Depelsenaire Alain Germeau 《国际泥沙研究》2019,34(5):486-495
Dredging operations produce considerable quantities of materials, to be managed and this opens an opportunity for valorization in civil engineering. However, the contamination of the dredged sediments has become a major problem to solve. The major contaminants are heavy metals and organic compounds. This study focuses on the use of phosphoric acid (H3PO4) to stabilize heavy metals from sediments and destroy organic matter by calcination at 650 °C with a goal of using sediments in roadworks. Several studies have been conducted in this eld. The stabilized materials obtained have been used in civil engineering. The main purpose of this work is to discuss the environmental behavior of marine sediment treated by phosphatation and calcination. Two types of phosphoric acids were used. The pH dependence leaching test has been used as the basic characterization to evaluate the effect of the type of phosphoric acid on the metals behavior in a valorization scenario. The standard leaching test and the Toxicity Characteristic Leaching Procedure (TCLP) were conducted as compliance tests. In regards of the obtained results, the environmental assessment has also shown a reduction in the availability of targeted heavy metals in alkaline environment whatever the type of acid used for treatment. This opens opportunities for co-valorization. 相似文献
52.
Béchir Béjaoui Ali Harzallah Mahmoud Moussa Annie Chapelle Cosimo Solidoro 《Estuarine, Coastal and Shelf Science》2008
This study deals with the use of a multivariate analysis method in order to understand the functioning of the Bizerte lagoon ecosystem. A set of hydrobiological parameters was collected during 10 monthly campaigns in 2004. A variant of the EOF (Empirical Orthogonal Function) technique is used to examine hydrobiological variability modes in this lagoon. The permanent features characterising the lagoon are obtained by applying the EOF technique to data after removing the annual cycle. Two major modes were obtained. The first one shows a contrast between the northern sector of the lagoon, influenced by the Mediterranean Sea, and the southern one influenced by continental waters. This mode is mostly prominent for temperature and salinity. The second mode shows a contrast between shallow waters along the coastal zones and the deep central area of the lagoon. This contrast is more pronounced towards the southwestern edge of the lagoon, a region of important freshwater input from the Tinja channel, which drifts towards the downstream area of Menzel Bourguiba. This second mode may also correspond to northward water circulation under southerly wind blowing frequently in summer. The spatial and temporal variability in the lagoon is highlighted by applying the EOF to the raw data without removing the annual cycle. A weight series is obtained for each variable by extracting the corresponding data and then projecting them on the corresponding eigenvector. Using this technique, only one mode was found dominant with more than 52% of the total variance. It was also found that the north–south contrast of temperature, salinity and phosphorous and the coast-centre contrast of Chlorophyll a are enhanced in summer. Other variables such as ammonia and nitrate also show significant annual cycles but with local patterns. 相似文献
53.
Jean‐Baptiste Charlier Roger Moussa Pierre‐Yann David Jean‐Franois Desprats 《水文研究》2019,33(17):2337-2354
The aim of this paper is to quantify peakflow attenuation and/or amplification in a river, investigating lateral flow from the intermediate catchment during floods. This is a challenge for the study of the hydrological response of permeable/intermittent streams, and our contribution refers to a modelling framework based on the inverse problem for the diffusive wave model applied in a karst catchment. Knowing the upstream and downstream hydrographs on a reach between two stations, we can model the lateral one, given information on the hydrological processes involved in the intermediate catchment. The model is applied to 33 flood events in the karst reach of the Iton River in French Normandy where peakflow attenuation is observed. The monitored zone consists of a succession of losing and gaining reaches controlled by strong surface‐water/groundwater (SW/GW) interactions. Our results show that despite a high baseflow increase in the reach, peakflow is attenuated. Model application shows that the intensity of lateral outflow for the flood component is linked to upstream discharge. A combination of river loss and overbank flow for highest floods is proposed for explaining the relationships. Our approach differentiates the role of outflow (river loss and overbank flow) and that of wave diffusion on peakflow attenuation. Based on several sets of model parameterization, diffusion is the main attenuation process for most cases, despite high river losses of up to several m3/s (half of peakflow for some parameterization strategies). Finally, this framework gives new insight into the SW/GW interactions during floods in karst basins, and more globally in basins characterized by disconnected river‐aquifer systems. 相似文献
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57.
M. K. Azer M. D. Samuel K. A. Ali H. A. Gahlan R. J. Stern M. Ren H. E. Moussa 《Mineralogy and Petrology》2013,107(5):829-848
The Wadi Allaqi ophiolite along the Egyptian-Sudanese border defines the southernmost ophiolitic assemblage and suture zone in the Eastern Desert. Ophiolite assemblages comprise nappes composed mainly of mafic and ultramafic rocks that were tectonically emplaced and replaced by serpentine and carbonates along shear zones probably due to CO2-metasomatism. Serpentinites, altered slices of the upper mantle, represent a distinctive lithology of dismembered ophiolites of the western YOSHGAH suture. Microscopically, they are composed of more than 90 % serpentine minerals with minor opaque minerals, carbonate, brucite and talc. The mineral chemistry and whole-rock chemical data reported here indicate that the serpentinized peridotites formed as highly-depleted mantle residues. They show compositions consistent with formation in a suprasubduction zone environment. They are depleted in Al2O3 and CaO similar to those in fore-arc peridotites. Also, high Cr# (Cr/ (Cr+Al)) in the relict chrome spinels (average ~0.72) indicates that these are residual after extensive partial melting, similar to spinels in modern fore-arc peridotites. Therefore, the studied serpentinites represent fragments of an oceanic lithosphere that formed in a fore-arc environment, which belongs to an ophiolitic mantle sequence formed in a suprasubduction zone. 相似文献
58.
Khalid S. Aldamegh Hesham Hussein Moussa S. Nasser Al-Arifi Sayed S. R. Moustafa Moustafa Hemeda Moustafa 《Arabian Journal of Geosciences》2012,5(4):599-606
Focal mechanism solution of the 27th August 2009 earthquake (mb?=?4.0) that occurred in the Badr area, northwest of Saudi Arabia, approximately 50?km from the Red Sea has been determined from the P-wave first motion polarities. Results show normal faulting mechanism with a negligible component of strike-slip motion with NE T-axis direction. This type of mechanism is common with other earthquakes of the northwestern Saudi Arabia and is considered to present the tectonic movement of the region. The dominantly extensional tectonic regime in this province demonstrates the influence of NE extension in the Red Sea. The strikes of the solution are consistent with those of the main faults near the epicenter. Hypocentral location of this earthquake was carried out using the data from the King Abdulaziz City of Science and Technology Seismic Network, Saudi Arabia, and the Egyptian National Seismological Network, Egypt. The horizontal and vertical confidence estimates are 0.5?km for both. The local magnitude, M L, following the Richter??s original definition was also derived from ten digital three-component broadband seismograms. The average local magnitude determined in this study is 3.8?±?0.17. The estimated seismic moment of this event is $ {3}.{\hbox{7e}} + {14}\,{\hbox{Nm}}\left( {{M_{\rm{W}}} = {3}.{66}\pm 0.0{7}} \right) $ . 相似文献
59.
Dia Sotto Alibo Hiroshi Amakawa Yoshiyuki Nozaki 《Journal of Earth System Science》1998,107(4):359-366
Two methods have been developed to measure indium (In) in natural waters by flow injection inductively coupled plasma mass
spectrometry (ICPMS). One is the isotope dilution technique using an113In enriched spike and the other utilizes natural yttrium present in the sample as an internal standard. In the former, optimization
of the113In spike to minimize error is often difficult for samples in which In concentrations are variable, whereas in the latter method,
a separate determination of Y in the sample is necessary and hence more sample is required. Using about 1 liter of a water
sample, 200 fold preconcentration of In was performed by solvent extraction and back extraction technique and then introduced
into the ICPMS to measure the113In/115In or115In/89Y ratios. The detection limits were 0.01–0.02 pmol kg−1 for both methods.
Application of the methods to seawater samples yielded the concentrations of 0.06–0.15 pmol kg−1 for the Pacific and 0.6–1.5 pmol kg−1 for the Atlantic. The large inter-oceanic variation of In best resembles that of Al amongst the 3B group of elements in the
periodic table. River and estuarine samples gave a more variable range of concentrations of 0.01–15 pmol kg−1. Most of the In supplied by rivers is removed by scavenging in the estuarine mixing zone, suggesting that the fluvial input
of In to the ocean is small. 相似文献
60.
Yayoi Hongo Hajime Obata Dia Sotto Alibo Yoshiyuki Nozaki 《Journal of Oceanography》2006,62(4):441-455
The concentration of dissolved rare earth elements (REE) were determined at 47 stations in the North Pacific surface waters.
Combining with other previous data, we present the surface REE distribution in the North Pacific and discuss the controlling
factors. The surface concentrations increase toward the high latitude and continental margin (e.g. [Nd] > 10 pmol kg−1) from the central North Pacific (e.g. [Nd] < 5 pmol kg−1). The North Pacific Deep Water-normalized REE patterns are varied, indicating that two or more factors contribute to the
REE distribution. We examined four factors making the regional variation of surface REE concentrations mainly; a) particle
scavenging, b) atmospheric dust input, c) vertical mixing and d) lateral transport from the coastal region. Flux calculations
for Nd showed that the influence of atmospheric dust was less significant than the vertical input even in the western upwelling
zone. Moreover, the longitudinal and latitudinal transitions of surface REE seem to reflect the lateral supply from the coastal
areas. We constructed the diagram of surface Er/Lu and Er/Yb molar ratios in order to assess the origin and the input processes
of the surface REE. Both molar ratios showed increasing trend toward PEW (Er/Lu (>10.5) and Er/Yb (>1.4)) from PSUW (Er/Lu
(>7) and Er/Yb (>1.2)). The high Er/Lu and Er/Yb ratios in PEW indicate that the lateral supply of terrestrial materials from
the coastal area is possibly the important factor in PEW, because only weathering and dissolution of rocks can explain such
high Er/Lu and Er/Yb ratios to our knowledge. 相似文献