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defluoridation of groundwater by calcined Mg/Al layered double hydroxide

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Emerging Contaminants 2016年第1期2卷 42-48页

作者： A.Elhalil S.Qourzal F.Z.Mahjoubi R.Elmoubarki M.Farnane H.Tounsadi M.Sadiq M.Abdennouri N.Barka Univ Hassan 1 Laboratoire des Sciences des Matéeriauxdes Milieux et de la Modélisation(LS3M)BP.14525000 KhouribgaMorocco equipe de Matériaux Photocatalyse et EnvironnementDépartement de ChimieFacultédes SciencesUniversitéIbn ZohrB.P.8106 CitéDakhlaAgadirMorocco

The present study evaluated calcined Mg/Al layered double hydroxide(CLDH)availability for the removal of fluoride from local *** Mg/Al layered double hydroxide(LDH)was synthesized by coprecipitation method and characterized by XRD,FT-IR and TGA-TDA *** defluoridation experiments were performed under various conditions such as calcination,solution pH,contact time,temperature,material dosage and *** results indicate that fluoride removal strongly increased after calcination of the LDH up to 600℃.The maximum fluoride removal was obtained at solution pH of *** of fluoride removal followed the pseudo-second order kinetic *** rise in solution temperature strongly enhances the removal *** adsorption mechanism involved surface adsorption,ion exchange interaction and original LDH structure reconstruction by rehydration of mixed metal oxides and concomitant intercalation of fluoride ions into the interlayer *** optimum dosages required to meet the national standard for drinking water quality were found to be 0.29 and 0.8 g/L,respectively,for Bejaad and Settat goundwaters.A decrease in the fluoride uptake with increasing the number of regeneration cycles was observed.

关键词： Fluoride removal Groundwater layered double hydroxide Drinking water quality

Theoretical investigation of the pressure broadening D1 and D2 lines of cesium atoms colliding with ground-state helium atoms

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Chinese Physics B 2019年第10期28卷 300-308页

作者： Moussaoui Abdelaziz Alioua Kamel Allouche Abdul-rahman Bouledroua Moncef Universite Cherif Messaidia B.P.1553Souk-Ahras 41000Algerie laboratoire de Physique de la matiere et du rayonnement LPMR Universite Cherif MessaidiaB.P.1553Souk-Ahras 41000Algerie Universite Lyon 1 CNRSLASIM UMR5579bat.A.Kastler43 Bd du 11 novembre 1918F-69622 VilleurbanneFrance laboratoire de Physique des rayonnements LPR Universite Badji MokhtarB.P.12Annaba 23000Algerie

Full quantum mechanical calculations are performed to determine the broadening in the far wings of the cesium D1 and D2 line shapes arising from elastic collisions of Cs atom with inert helium atoms. The potential energy curves of the low-lying CsHe molecular states, as well as the related transition dipole moments, are carefully computed from ab initio methods based on state-averaged complete active space self-consistent field-multireference configuration interaction(SACASSCF-MRCI) calculations, involving the spin-orbit effect, and taking into account the Davidson and BSSE *** absorption and emission reduced coefficients are determined in the temperature and wavelength ranges of 323-3000 K and 800-1000 nm, respectively. Both profiles of the absorption and the emission are dominated by the free-free transitions,and exhibit a satellite peak in the blue wing near the wavelength 825 nm, attributed to B^2Σ1/2^+→ X^2Σ1/2^+/transitions. The results are in good agreement with previous experimental and theoretical works.

关键词： absorption coefficient emission coefficient pressure broadening potential curves

Dynamics of Water Flow in the Atmosphere-Aerial Roots Continuum

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Open Journal of Fluid Dynamics 2018年第4期8卷 404-415页

作者： Médéhouénou Enagnon Alexis Kounouhéwa Bruno Basile Koutchadé Clément Centre Béninoise de la recherche Scientifique et de l’Innovation (CBRSI)-IRITESE Université d’Abomey-Calavi (UAC) Faculté des sciences et Technique (FAST) laboratoire de Physique du rayonnement (LPR)

The study of the parameters influencing the absorption of atmospheric humidity not condensed by plants with aerial roots is a challenge in the current context of climatic disturbance where methods of adapting plants to water stress have become the concern of many scientific researchers. Based on Poiseuille and Fick laws, leaf water potential depending on solar radiation and atmospheric water potential around aerial roots;the influence of temperature, relative humidity, inclination angle of roots and solar radiation wavelength on the radial and axial water flow through a root segment is simulated. The various simulations show that a low temperature of the air surrounding the root favors a significant entry of water into the root as well as a relative humidity of the high air approaching 100%. The angle of inclination has an influence on the quantity of water entering the root and that rising in the xylem. These different streams of water are optimized for root tilting of 60°. The wavelength of the red radiation received by the leaves favors more entry and rise of water in the root. Future studies for transgenes should be taken into account the influence of all these parameters.

关键词： Plant Aerial Root Absorption Atmospheric Humidity

Study of Tungsten Phosphate Glasses Containing Fe<sub>2</sub>O<sub>3</sub>

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New Journal of Glass and Ceramics 2019年第3期9卷 33-49页

作者： Hicham Es-Soufi lahcen Bih Meyrem Benzineb equipe de Physico-Chimie de la matière Condensée PCMC Faculté des Sciences de Meknès Université Moulay Ismail Meknès Morocco Département matériaux et procédés ENSAM Meknès Université Moulay Ismail Meknès Morocco

Glasses of the compositions 20Li2O-(50 - x)Li2WO4-xFe2O3-30P2O5 where (x = 0, 1, 5, 8, 10, 15 mol%) were elaborated by the melt-quenching route. Synthesized glasses are characterized using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), differential scanning calorimetric?(DSC), and density determination. The XRD patterns confirmed the?amorphous nature of samples, and IR spectra showed the structural groups and highlight the depolymerization of phosphate network with the introduction of iron oxide. It is found that the structural unit Q2 converts to Q1 and Q0 as Fe2O3 replaces Li2WO4. Chemical durability tests on the glasses have shown that the compositions containing pyrophosphate (Q1) and orthophosphate (Q0) units are more water-resist. The electrical conductivity measurements were performed by complex impedance spectroscopy in the frequency range of 20 - 106 Hz at various temperatures from ambient to 400°C. It is found that the conductivity is activated thermally and follows an Arrhenius law. The obtained electrical data were analyzed by the modulus formalism and dielectric formalism. The determined asymmetric nature of? spectra suggested that the relaxation behavior is non-debye and characterized by the stretched exponent parameter

关键词： Phosphate Glasses Thermal Analysis Structure Electrical Conductivity

Extracts from Marine Macroalgae and Opuntia ficus-indica Cladodes Enhance Halotolerance and Enzymatic Potential of Diazotrophic Rhizobacteria and Their Impact on Wheat Germination Under Salt Stress

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Pedosphere 2018年第2期28卷 241-254页

作者： Abdelwahab RAI Ameur CHERIF Cristina CRUZ Elhafid NABTI Département de Microbiologie Faculté des Sciences de la Nature et de la Vie Université Ferhat Abbas Sdtif-1 19000 (Algdrie) Universitg de Béjaia FSNV Laboratoire de Maitrise des Energies Renouvelables (LMER) Equipe de Biomasse et Environnement Targa Ouzemmour Béaia 06000 (Algérie) LR Biotechnology and Bio-Geo resources Valorization Higher Institute for Biotechnology University of Manouba Sidi Thabet Biotechpole 2020 Sidi Thabet Ariana 2080 (Tunisia) cE3c-Centre for Ecology Evolution and Environmental Changes Campo Grande Bloco C-2 Piso 5 Sala 03 Lisboa 1749-016 CPor- tugal)

Soil salinity, which affects more than 6% of the earth’s land surface and more than 20% of its irrigated areas, is a major threat to agriculture. Diazotrophic bacteria are among the functional groups of soil microbiota that are threatened by this abiotic stress, as their activity is mostly inhibited by salt stress. Seventy bacterial strains with distinct characteristics were isolated from soils by using N-free Jensen’s selective medium. Based on their ability to produce metabolites of agricultural interest, four strains were selected and identified as Flavobacterium johnsoniae, Pseudomonas putida, Achromobacter xylosoxidans, and Azotobacter chroococcum. The selected strains were grown at different NaCl concentrations (0–600 mmol L^(-1) in N-free broth and 0–2 000 mmol L^(-1) in Luria-Bertani medium) in the presence and absence of glycine betaine (GB), aqueous and hydro-alcoholic extracts from marine macroalgae, Ulva lactuca and Enteromorpha intestinalis, and Opuntia ficus-indica cladodes. The selected bacterial strains, GB, and the aforementioned extracts were tested for their ability to promote the germination of wheat (Triticum durum) seeds at 0–300 mmol L^(-1) NaCl. Compared with the results obtained with the synthetic osmoprotectant GB, the extracts from O. ficus-indica, U. lactuca, and E. intestinalis significantly promoted bacterial growth and seed germination under salt stress.

关键词： glycine betaine Ulva lactuca Enteromorpha intestinalis plant growth-promoting rhizobacteria (PGPR) seed germi-nation Triticum durum

Effect of Cultural Practices on the Growth of Date Palm VitroPlants Planted in Errachidia （South East of Morocco）

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Journal of Life sciences 2017年第6期11卷 279-285页

作者： reda Meziani Chakib Alem Abdelhi Dihazi Brahim Rabach Mustapha Ait Chitt Fatima Jaiti laboratoire National de culture des tissus de palmier dattier lnstitut National de la Recherche Agronomique Errachidia 52000 Morocco equipe Biochimie des ressources Naturelles Universitd My lsmail Meknes Facultk des Sciences et Techniques Errachidia 52000Morocco laboratoire de Biotechnologie de la Valorisation et de la Protection des Agroressources UniversitO Cadi Ayyad Facult~ desSciences et Techniques Marrakeeh 40000 Morocco equipe Protection Amdlioration et dcophysiologie vegetales Universite My Ismail Meknes Faculte des Sciences et Techniques Errachidia 52000 Morocco laboratoire de Biotechnologie Domaine El Bassatine Meknes 50020 Morocco

In vitro multiplication of date palm is a very promising way for the rehabilitation of Moroccan palm devastated. The objective of this work was to study the development of vitroplants introduced into traditional and modem palm of the Errachidia region. The procedure followed is to make descriptive diagnoses in different sites where the palm was introduced and to evaluate the mortality of plants and cultural practices. The mortality rates varied from 78% to 19% in new plantation depending on the cultivation technique used. At the traditional palm, the rate of recovery ofplantlets was zero. The mortality is higher in Nejda cultivar compared to Boufegouss. This variety also presented a better adaptation in terms of shoot height in comparison with the development of Nejda and Mejhoul varieties. The production of offshoots as well as inflorescences takes place three years after plantation. The importance of improving cultivation techniques in date palm for the development of this sector in Morocco is discussed.

关键词： Date palm cultural practices vitroplants Phoenix dactylifera.

Long-Term Trends and Its Best Functional Form Estimation of Yearly Maximum and Minimum Temperatures at Cotonou City by Improved Complete Ensemble Empirical Mode decomposition with Adaptive Noise Method

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Atmospheric and Climate sciences 2022年第1期12卷 31-42页

作者： Médard Noukpo Agbazo Joseph Adébiyi Adéchinan Gabin Koto N’gobi Joseph Bessou International Chair in Mathematical Physics and Applications (CIPMA-Chair Unesco) Université d’Abomey-Calavi UAC Cotonou Bénin laboratoire de Physique du rayonnement (LPR) Faculté des Sciences et Techniques Université d’Abomey-Calavi UAC Cotonou Bénin Département de Physique Faculté des Sciences et Techniques Université Nationale des Sciences Technologies Ingénierie et Mathématiques (UNSTIM) Abomey Bénin Agence Nationale de la Météorologie du Bénin Meteo Bénin

The understanding of the long-term trend in climatic variables is necessary for the climate change impacts studies and for modeling several processes in environmental engineering. However, for climatic variables, long-term trend is usually unknown whether there is a trend component and, if so, the functional form of this trend is also unknown. In this context, a conventional strategy consists to assume randomly the shape of the local trends in the time series. For example, the polynomial forms with random order are arbitrarily chosen as the shape of the trend without any previous justification. This study aims to 1) estimate the real long-term nonlinear trend and the changing rate of the yearly high temperature among the daily minimum (YHTaDMinT) and maximum temperatures (YHTaDMaxT) observed at Cotonou city, 2) find out for these real trend and trend increment, the best polynomial trend model among four trend models (linear, quadratic, third-order and fourth-order polynomial function). For both time series, the results show that YHTaDMinT and YHTaDMaxT time series are characterized by nonlinear and monotonically increasing trend. The trend increments present different phases in their nonmonotone variations. Among the four trend estimations models, the trend obtained by third-order and fourth-order polynomial functions exhibits a close pattern with the real long-term nonlinear trend given by the Improved Complete Ensemble Empirical Mode decomposition with Adaptive Noise (ICEEMDAN). But, the fourth-order polynomial function is optimal, therefore, it can be used as the funct

关键词： Long-Term Trends Polynomial Trend Models Trend Increment ICEEMDAN Extrema Temperature

Effects of soil metal(loid)s pollution on microbial activities and environmental risks in an abandoned chemical smelting site

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Journal of Environmental sciences 2024年第9期143卷 60-70页

作者： Hao Li Jun Yao Jianli Liu Ning Min Geoffrey Sunahara Dongyang Men Robert duran School of Water resources and Environment Research Center of Environmental Science and EngineeringChina University of Geosciences(Beijing)Beijing 100083China department of Natural resource sciences McGill University21111Lakeshore DriveSte-Anne-de-BellevueQuebecH9X 3V9Canada equipe Environnement et Microbiologie MELODY groupUniversitéde Pau et des Pays de l’AdourE2S-UPPAIPREM UMR CNRS 5254BP 115564013 Pau CedexFrance

Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological *** samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial *** potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which Cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(MCR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental *** the near-surface samples(S-0 and D-1 layers),the MCR considered that As,Cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution *** microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity *** analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(petabolic activity in the D-1 layer was low presumably due to heavy metal *** activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.

关键词： Abandoned chemical smelting sites Microbial activities Modified combined pollution risk Microcalorimetry Enzymatic activities

Analysis and Predictability of Dry Spell Lengths Observed in Synoptic Stations of Benin republic (West Africa)

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American Journal of Climate Change 2021年第4期10卷 597-618页

作者： Médard Noukpo Agbazo Joseph Adébiyi Adéchinan Gabin Koto N'gobi Joseph Bessou International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair) Université d’Abomey-Calavi Abomey-Calavi Bénin laboratoire de Physique du rayonnement (LPR) Université d’Abomey-Calavi Abomey-Calavi Bénin Département de Physique Faculté des Sciences et Techniques Université Nationale des Sciences Technologies Ingénierie et Mathématiques (UNSTIM) Abomey Bénin Agence Nationale de la Météorologie du Bénin (MetEO BENIN) Cotonou Bénin

The complex behavior and predictability of the Dry Spell Lengths (DSL) series obtained in Benin synoptic stations, from 1951 to 2010 are analyzed in this paper using a fractal approach. The synoptic stations are located in Cotonou, Bohicon, Save (subequatorial climate), and Parakou, Natitingou, Kandi (Sudanian climate). The DSLs are computed by considering four thresholds level, R0 = {1.0, 1.5, 2.0 and 5.0} mm/day. The fractal trace is estimated for dry spell density by the mean of the “Dry Spell Spell” (DSS) n-index. The rescaled range method is used to determine the predictability of DSL. By analyzing the DSS, results show that low DSS n-index values (n-index re more favored in the northern part of Benin than in the southern region, whereas, high values of DSS n-index (n-index > 0.4) occur preferentially in the southern part. Therefore, during 1951-2010, the Sudanian region presents frequent wet spells, alternated with short dry spells than in the subequatorial one. However, a high degree of long dry spell persistence, followed by short dry events is observed in the subequatorial region than in the Sudanian one. The longest DSL is observed in the subequatorial region, especially in Cotonou. Except for the Kandi station, the DSLs series obtained at synoptic stations are characterized by persistence. Therefore, autoregressive processes could be applied to the DSL series. Generally, the physical process governing dry spells observed at Save, Natitingou, and Bohicon are consistently predictable than the process governing the stations of the Cotonou and Parakou. However, at Kandi station, the DSL process approximates the usual Brownian motion, and it is, therefore, unpredictable or difficult to predict.

关键词： Hurst Exponent N-Index DSL Predictability Complex Behavior Benin