排序方式: 共有32条查询结果,搜索用时 10 毫秒
21.
Eshaghi Attieh Aoudia Abdelkrim Shahvar Mohammad P. Farzanegan Esmail 《Journal of Seismology》2022,26(5):883-895
Journal of Seismology - In this study, seismic moment, moment magnitude, and the corner frequency of Iranian earthquakes were estimated using the Iran Strong Motion Network (ISMN) data. To estimate... 相似文献
22.
23.
Khadhar Samia Achouri Dhouha Chekirben Anis Mlayah Ammar Azibi Rim Charef Abdelkrim 《Arabian Journal of Geosciences》2018,11(2):34
Toxic organic compounds in wastewater are serious threats for both human and environment healthy states. This study investigates the potential sources of surface water, sediment and groundwater pollution by polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyl (PCBs) as discharged by wastewater into the River of Oued El bey in northeastern Tunisia. Analysis indicates that the concentration of PAHs and PCBs are high in wastewater and vary from 0.37 to 0.83 mg/L and from 0.28 and 1.18 mg/L, respectively. The spatial distribution of PAHs and PCB in surface water showed a variation between 0.37 to 9.91 mg/L and between 0.1 to 0.47 mg/L, respectively. However, the quality of surface water is changed after wastewater evacuation at Oued Tahouna. The determination of PAH and PCB pollutants in groundwater shows a great interest in the development of water resources. The Concentration of these pollutants varying from 0.0204 to 1.93 mg/L and from 0.0052 to 0.196 mg/L, respectively. For PAH, analysis reveals also that naphtelene, fluorene, anthracene and chrysene are the most detected PAHs compounds in water and sediment samples while benzo[b]fluoranthene and benzo[a]pyrene are less present and in trace level. Higher concentrations of PAHs and PCBs are found in samples taken close to industrial areas of Bouargoub and Soliman, and wastewater discharge locations in Soliman. Analysis of the spatial distribution of PAHs and PCBs clearly link their higher concentration in water and sediments to wastewater and manufacturing discharges in the study area. In surface sediment, the organic pollutants are present. The cluster analysis for organic pollutants in different state and different matrix highlight a relationship between the wastewater evacuation and the water qualities which confirmed the direct response of the pollution sources on the surface water and groundwater organic pollution quality. 相似文献
24.
Mina Nassiry Claude Aubert Abdelkrim Mouzdahir Jean-François Rontani 《Organic Geochemistry》2009,40(1):38-50
In order to mimic the photodegradation of vitamin E during phytoplankton senescence and study the behaviour of the resulting photoproducts during cell lysis, vitamin E dispersed in seawater was irradiated with solar light in the presence of hematoporphyrin as sensitizer. Under these conditions, singlet oxygen-mediated photooxidation and free radical oxidation (autoxidation) acted simultaneously on the substrate, affording 4,8,12-trimethyltridecanal, 4,8,12-trimethyltridecanoic acid, 6,10,14-trimethylpentadecan-2-one, α-tocopherylquinone, 4,8,12,16-tetramethylheptadecan-4-olide, 2,3-epoxy-α-tocopherylquinone and 5,6-epoxy-α-tocopherylquinone as minor products. Different mechanisms were proposed to explain the formation of these different isoprenoids. The main products (85% of the degraded substrate) appeared to be previously described diastereoisomeric trimeric oxidation products of vitamin E, whose pyrolysis during gas chromatography–mass spectrometry (GC–MS) afforded 2,6,10,14-tetramethylpentadec-1-ene (prist-1-ene). On the basis of their greater ability to produce prist-1-ene during pyrolysis than intact vitamin E and their highly favoured production in phytoplanktonic cells, these trimers are proposed as likely sources of this isoprenoid alkene, previously identified in many pyrolysates from immature kerogens. 相似文献
25.
Ammar Mlayah Eduardo Anselmo Ferreira Da Silva Fethi Lachaal Samia Khadhar Abdelkrim Charef Fernando Noronha 《水文科学杂志》2013,58(3):686-705
Résumé Le Nord-Ouest de la Tunisie renferme plus que 81% des eaux de surface et 95% des mines et gîtes miniers. Le bassin versant de l'Oued Mellègue, situé dans cette zone, englobe 13 mines de plomb, zinc, fer, strontium, fluor, barium et phosphates. L'impact des rejets de ces mines sur les eaux de surface a été apprécié grâce à plusieurs compagnes d’échantillonnage. Les résultats d'analyse par ICP/MS de ces échantillons montrent qu'ils renferment des quantités non négligeables d'Al, As, B, Ba, Br, Cd, Co, Cr, Cu, Hg, Mo, Ni, Sr, U et de Zn. L'analyse des ces éléments dans les eaux du Mellègue, de ses affluents et dans la retenue de Nebeur montre que leurs concentrations sont inférieures aux normes d'eau potable. Ce comportement pourrait être dû à la nature des affleurements géologiques formés par des carbonates des argiles et des évaporites, à l'absence de cours d'eau drainant directement les rejets, à la formation de minéraux secondaires caractérisés par une importante rétention des métaux et à l’étendue des bassins versants non pollués. 相似文献
26.
A combined 5% sodium hypochlorite (<24 hr.) followed by silver phosphate (15–20 mn) pre-treatment process has been developed for the isotopic analysis of calcite- or dolomite-bearing samples associated with organic matter and sulphide minerals. This treatment purifies the CO2 gas of contaminant sulphur-bearing organic species and H2S which are generated during the reaction of the sample with phosphoric acid. 相似文献
27.
Abdelkrim Torbi 《Journal of African Earth Sciences》1996,22(4):549-563
In the Paleozoic basement of the southeast Oujda mountains, the Lower Ordovician, Silurian-Devonian and Devonian-Dinantian are dated for the first time through palynology. This paper shows the autochtonous character and continuous stratigraphy of the formations of the Lower Ordovician to Devonian or probably Dinantian. The Intra-Visean Olistostrome is interpreted as a tectono-sedimentary breccia associated with strike-slip faults. The structural Variscan evolution is characterized by two major phases, each of them being divided in three stages. The ante-Upper Visean early phase is characterized in chronological order by (1) submeridian folds, (2) northeast-southwest folds and (3) extensional, oblique-slip, east-west trending faults. The second phase post-dates the Westphalian C and is marked by open east-northeast - west-southwest trending folds cut by reverse faults with the same trend and by a set of north-south sinistral and east-west dextral strike-slip faults. These later faults have allowed the emplacement of late Hercynian granitoïds.A palaeogeographical and structural reconstruction comparable to that established in the rest of the Moroccan Meseta is proposed. 相似文献
28.
Environmental degradation and other socio-economic problems are too often discerned in contemporary pastoral systems in the
wake of global economic change. This paper identifies cases where pastoral people respond to external pressures and opportunities
in positive ways and adapt to changes. We hope that by doing this a framework of pastoral adaptations can be developed. The
first part of this paper focuses on impacts of global economic change, which are mostly negative in nature. Through an extensive
literature search in geography, anthropology, range management, and development field, the second part introduces cases that
we categorize as positive adaptations. 相似文献
29.
30.
Benamar Ahmed Correia dos Santos Ricardo N. Bennabi Abdelkrim Karoui Tarek 《Acta Geotechnica》2019,14(3):815-823
Acta Geotechnica - An experimental study on internal erosion of coarse-grained soils collected from the Rhine River is presented. The tests performed on laboratory column aim to assess the... 相似文献