Évolution de la pollution des eaux de l’Oued El Mellah (Djelfa région steppique de l’Algérie)

La steppe Algérienne couvre une superficie de 20 millions d’hectares, en plus du manque des ressources en eaux que connaît ce domaine, vient s’ajouter le phénomène de pollution. La croissance démographique et urbaine importante de la ville de Djelfa accroît les quantités de rejets d’eaux usées dans l’oued El Mellah qui traverse cette ville. A partir d’un suivi saisonnier de la qualité des eaux de cet oued dans cinq stations d’échantillonnages, on a constaté l’ampleur de la pollution organique et minérale qui dépasse les normes. L’effet de dilution lié à la précipitation, diminue la pollution des eaux entre les mois d’octobre et mai.Mots-clés : eau usée, oued, pollution, Djelfa, Algérie

On the age of Ain Hanech Oldowan locality (Algeria): First numerical dating results

Our current understanding of early human settlements in North Africa relies on a few well-contextualized Oldowan and Acheulean sites (e.g., Ain Hanech, El Kherba, Ain Boucherit Lw and Up, Tighennif in Algeria; Thomas Quarry in Morocco). In particular, the site of Ain Hanech has documented for many decades the earliest evidence of human presence in North Africa (e.g., Sahnouni and de Heinzelin, 1998), until older stone tools were recently reported at the nearby Ain Boucherit locality (Sahnouni et al., 2018). While the Early Pleistocene antiquity of this Oldowan assemblage has never really been questioned, its exact age has, however, been discussed. In the early 2000s, a series of articles were published in this journal arguing either for an age of ~1.8 Ma (Sahnouni et al., 2002, 2004) or much younger, around 1.2 Ma (Geraads et al., 2004). Although subsequent chronostratigraphic studies have provided additional evidence for the older age (Pares et al., 2014 ; Sahnouni et al., 2018; Duval et al., 2021), Ain Hanech site had never been numerically dated until now. Moreover, beyond the archeological relevance of the site, Ain Hanech faunal association has also long been used as a reference for biochronological inferences and comparative studies with other paleontological localities of the region (e.g., Geraads, 2002; Sahnouni et al., 2002; Van der Made and Sahnouni, 2013; Van der Made et al., 2021). In other words, the accuracy of North African biochronology over the Early Pleistocene timescale partly relies on the age of Ain Hanech. In this context, we present here the dating results from electron spin resonance (ESR) and uranium-series (U-series) methods tentatively applied to optically bleached quartz grains and fossil teeth from Ain Hanech and the nearby stratigraphically equivalent site of El Kherba (Sahnouni and de Heinzelin, 1998).Spanish Ramon y Cajal Fellowship RYC2018-025221-I granted to M.D. is funded by MCIN/AEI/10.13039/501100011033 and by ‘ESF Investing in your future’. This work is part of Grant PID2021-123092NB-C22 funded by MCIN/AEI/10.13039/501100011033/‘ERDF A way of making Europe’. Fieldwork and related research at Ain Hanech were funded with grants awarded to M.S. by CNRPAH (Algeria), MCIN and MINECO (PGC2018-095489-BI00 and HAR2013-41351-P, respectively; Spain), the L.S.B. Leakey Foundation (USA), the European Research Council (FP7-PeopleCIG2993581; Belgium), and the Stone Age Institute (USA), and to S.A. by UMR7194 (CNRS, MNHN; France).Peer reviewe

Ice loads on electric power generating stations to harness ocean energy in the Belle Isle Strait

Recently, the provincial government of Newfoundland and Labrador, Canada, issued a call for a pre-feasibility study for potential construction of a fixed link between Newfoundland and Labrador. Several concepts/ideas have been proposed. One old and popular concept is the construction of an immersed tunnel across the Belle Isle Strait (BIS). An alternative concept calls for the construction of a series of large concrete hydroelectric stations across the BIS and use these stations as piers for a bridge between Newfoundland Island and Labrador. Potentially, the ?bridge? will pay for itself over time by generating electric energy from the natural tides in the strait. The main objective of this research project is to conduct a study to evaluate the structural stability and the economic viability of the proposed power-generating stations across the BIS. The task of the structural stability deals with concerns related to whether or not the concrete hydroelectric stations are able to withstand the environmental loads (ice and hydrodynamic loads). The task of the economic viability, however, deals with estimating the electric power capacity that can be generated from the natural tidal waves and current in the strait. In this paper, the work on the task for the structural stability of the concrete hydroelectric stations is summarized. More specifically, the results given in the paper are those dealing with the predictions of maximum ice loads on the concrete stations. The hydrodynamic load predictions and the calculations of the electric power capacity are beyond the scope of this paper.Peer reviewed: YesNRC publication: Ye

Évaluation de la pollution chimique par le zinc et le fer de la nappe profonde des graviers d'Annaba (Nord-Est d'Algérie)

La maîtrise de la gestion des ressources en eau souterraine relève de la bonne connaissance des équilibres hydrauliques, hydrochimiques et biologiques qui conditionnent l'avenir socio-économique régional. A l'exemple du bassin hydrologique de la Seybouse (Nord-Est de l'Algérie), les activités humaines déployées dans les vallées et les plaines adjacentes ont évidemment d'importantes répercussions sur ces équilibres. La région d'étude constitue un pôle important d'industrie lourde et de transformation. La pollution industrielle est provoquée par les rejets thermiques, chimiques et organiques par voie aquatique terrestre ou atmosphérique. Les unités industrielles qui sont des points potentiels ou réels de pollution sont nombreuses (plus d'une dizaine) notamment les usines sidérurgiques, métalliques et pétrochimiques. Une analyse piézométrique et hydrochimique a été réalisée en 15 stations s'étendant du Nord vers le Sud entre Annaba et Bouchegouf dans le Nord-Est de l'Algérie. Ces analyses ont concerné les concentrations en chlorures et en sulfates dans les eaux des aquifères ainsi que celles de fer et de zinc. La période d'échantillonnage en avril 2002 a été celle des hautes eaux

Biodosimetry of radiation-induced effects on DNA damage and cell cycle.

Molecular biological markers of radiation response are thought to be of potential use to monitor the progress of radiation therapy and also to predict at an early stage the outcome of a radiotherapeutical treatment. They might also be a tool to monitor the populations potentially exposed after a radiological accident or a "dirty bomb" incident but also to monitor astronauts during a spaceflight during which they are submitted to cosmic radiations. The bone marrow and the blood are the most radiation sensitive tissues of the human body. Therefore, the specific study of the radiation effects on mononuclear cells is of particular importance to find radiation-induced biological markers. The study of radiation biomarkers includes DNA mutation, chromosome aberrations, apoptosis as well as protein, gene expression by the array technologies and cell cycle after propidium iodide staining. However, additional studies are needed to validate candidate biomarkers (molecular and/or proteic) for applied biological dosimetry applications and that could provide early and rapid information after exposure to radiation. In human mononuclear cells, we studied the effects of X- and gamma rays at low doses (from 0.015625, 0.03125, 0.0625, 0.125 to 0.25 Gy) to high doses (0.25, 0.5, 1, 2, 4, 6, 10, 15 and 20 Gy) on DNA damage and cell cycle. DNA damage was monitored by the 8-oxyDNA assay and the apoptosis by cell cycle analysis after Propidium Iodide staining and size reduction. The results show that X or gamma radiations induced a dose-dependent increase of DNA damage in mononuclear cells in comparison with the control samples. Moreover, cell cycle and the size reduction showed a higher number of cells in the sub-G1 phase (caracterising the apoptotic cells) in irradiated cells in comparison with the control. However, the pattern of the induction of the radiation-induced effects is different in function of the protocol applied (DNA damage, the cell cycle and the size reduction). This can be explained by the different radiosensitivities of the subpopulations amongst mononuclear cells and also the variation in intrinsic radiation sensitivities between individuals. This work is supported by a Belspo contract (BL/52/C43) and an ESA-Belspo contract (CO-90-2141)

First-year ridge loads on moored offshore structures

This paper describes the background, test methodology, experiment program and analytical methods used for a project to predict the peak mooring system loads that occur when a floating offshore structure encounters a first year ice ridge. The project included the construction of simplified physical models of a Spar at 1/30 scale and a Floating Production Unit (FPU) at 1/40 scale. The Spar was a representative structure with a downward breaking cone and a vertical neck designed for operation in ice. A partial spar, consisting of the cone only was also evaluated. The Floating Production Unit (FPU) was a simplified barge. This model was tested with a rigid connection to the towing carriage and also on a representative mooring system that allowed for some compliance. The model FPU was also fitted with two load measuring panels designed to measure local ice loads on the hull. The methods of producing the model ridges and measuring their physical properties are described. Each model was tested in a range of ridge geometries from temperate to Arctic regions. The experiments were carried out in the ice tank of the National Research Council of Canada's Institute for Ocean Technology. This paper describes the first phase of experiments on the spar model completed in December 2009 and the first phase of experiments on the FPU completed in June 2010. The paper also presents the description of a parallel numerical approach to the problem, which looks at the methods needed to model the ridge-structure interaction using finite element methods. The results of the simulations and experiments are discussed in general terms. Copyright 2011, Offshore Technology Conference.Peer reviewed: YesNRC publication: Ye

A biodegradable starch based coating to waterproof hydrophilic materials

2 tables 4 graph.International audienc

Recent model submarine experiments with the MDTF

DRDC and NRC-IOT have collaborated on testing a model of the Victoria class submarines at IOT in St. John's. Hydrodynamic coefficients derived from these experiments will be used in numerical models to simulate manoeuverability and emergency recovery. We summarize the test programs and results so far, and illustrate derivation of the principal coefficients. A qualitative comparison is made with other data and semiempirical predictions. An additional test program scheduled for late 2007 complete the experimental component of this work.NRC publication: Ye

Preliminary results of ship maneuvering in ice experiments using a planar motion mechanism

Ship maneuvering experiments in ice are being conducted at the Institute for Ocean Technology (IOT) of the National Research Council of Canada. The aim is to provide a model test database for a subsequent mathematical and numerical modeling of the interaction processes between the ship and ice. The first phase of the experiments was carried out using a 1:21.8 scaled model of the Canadian Icebreaker, Terry Fox. The test program included straight resistance runs and turning circles maneuvers achieved by using a Planar Motion Mechanism (PMM) apparatus. In each experiment tow forces, turning moments, and ship motions were measured. In this paper, preliminary results of the experimental program are presented. The dominant ice-ship interaction processes are identified. The test results show large influence of ship motions and interaction geometry on the measured yaw moments. The geometrical aspect of the interaction processes is described and its influences on ice loads are discussed. Conclusions are made and recommendations for future works are provided.NRC publication: Ye