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Do aeolian deposits and sand encroachment intensity shape patterns of vegetation diversity and plant functional traits in desert pavements?

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Journal of Arid Land 2023年第6期15卷 667-694页

作者： m'hammed BOUALLALA Souad NEFFAR Lyès BRADAI Haroun CHENCHOUNI Laboratory of Saharan Natural Resources Faculty of Sciences and TechnologyUniversity of Ahmed DraiaAdrar 01000Algeria Department of Nature and Life Sciences Faculty of Exact Sciences and Nature and Life SciencesUniversity of TebessaTebessa 12002Algeria Laboratory Water and Environment University of TebessaTebessa 12002Algeria Laboratory of Saharan Bioresources Preservation and Valorization Faculty of Nature and Life SciencesUniversity of Kasdi MerbahOuargla 30000Algeria Department of Forest management Higher National School of ForestsKhenchela 40000Algeria Laboratory of Natural Resources and management of Sensitive Environments University of Oum-El-BouaghiOum-El-Bouaghi 04000Algeria

The effects of sand encroachment on composition,diversity,and functional patterns of vegetation in drylands are rarely studied,and yet addressing these aspects is important to deepen our understanding of the biodiversity *** study a.m.d to investigate the effect of sand encroachment on plant functional biodiversity of desert pavements(gravel deserts)in the Sahara Desert of *** were sampled and analyzed in three desert pavements with different levels of sand encroachment(LSE)and quantity of aeolian deposits(low,LLSE;medium,mLSE;and high,HLSE).Within the sample-plot area(100 m^(2)),density of every plant species was identified and total vegetation cover was *** taxonomic and functional diversity were analyzed and compared between *** showed that 19 plant species in desert pavements were classified into 18 genera and 13 *** and Poaceae were the most important *** species Anabasis articulata(Forssk)*** LLSE desert pavements with 11 species,whereas Thymelaea.m.crophylla Coss.&Durieu ex *** Calobota saharae(C&D)Boatwr.&van Wyk were dominant species of desert pavements with mLSE(14 species)and HLSE(10 species),*** highest values of species richness and biodiversity were recorded in desert pavements with mLSE,while low values of these ecological parameters were obtained in desert pavements with *** pavements with LLSE were characterized with the highest values of species *** communities were dominated by chamaephytes,anemochorous,arido-active,and competitive stress-tolerant *** increase in LSE along the gradient from LLSE to HLSE induced significant changes in plant community variables including decreases in plant density,plant rarity,lifeform composition,morphological type,and aridity *** pavements with HLSE favor the degradation of vegetation and trigger biodiversity erosion.

关键词： desert pavements hot and arid rangeland plant diversity land degradation sand encroachment plant functional trait Sahara Desert

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Abundance and Distribution,Growth Pattern,Sex Ratio and Gonadosomatic Index(GSI)of Liza falcipinnis(Valenciennes,1836)from Ojo Axis of Badagry Creeks,Lagos,Nigeria

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Sustainable marine Structures 2021年第2期3卷 39-49页

作者： Adeboyejo O.A. Clarke E.O. hammed a.m. Whenu O.O. Abayomi J.P. Olarewaju O.m. Department of Fisheries Faculty of ScienceLagos State UniversityOjoLagosNigeria

A study on seasonal abundance,morphometric and meristic data,growth pattern,condition fector,sex ratio and gonadosomatic index of Liza falcip-innis(Wlenciennes,1836)from the Ojo axis of Badagry creek,Nigeria was conducted from may 2019 to march 2020.A total of 1012 species were randomly selected,having 499 females and 513 *** length frequency analysis and length-weight relationships(LWR)were *** ratio was determined by Chi-square *** results showed that morphometric data are:0.5-2.5 mm for ED,2.1-12 mm for HL,1.7-8.1 mm for HD,2.5-11.7 for BD,2.6-233.3 mm for TL and 9.23-1006 g for BW for the combined *** slope(b)shows an allometric growth *** intercept'a'and slope'b'of the LWR(LogW=a+bLogL)were Log W=15.39+0.34 LogL(r=0.54)for combined sexes,Log W=12.49+0.02 log L(r=0.38)for males and Log W=18.23+0.01 log L(r=0.16)for *** length frequency distribution indicated that species were dominated by two year classes(Ages 1 and 2).Condition factors were generally *** values ranged between 0.68-0.85 for combined *** gonadosomatic index for female was highest in August,2019(17.77%)with mean±SD of 2.88±0.75;which indicated the peak of spawning period in the study *** ratio difference was significant(Pmales are phenotypically larger than the male.

关键词： Growth pattern Length-weight-relationships(LWR) Gonadosomatic index(GSI) Condition factor Creeks Fish biology

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Influence of mulch and poultry manure application on soil temperature,evapotranspiration and water use efficiency of dry season cultivated okra

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International Soil and Water Conservation Research 2023年第2期11卷 382-392页

作者： mutiu Abolanle Busarit Ganiyu Olawale Bankole Idris Adebanjo Adiamo Rasaq Olayiwola Abiodun Olanrewaju hammed Ologunde Department of Soil Science and Land management Federal University of AgricultureAbeokutaPM.B2240AbeokutaNigeria

Sustainable vegetable production especially during the dry season requires adequate conservation of soil *** study was conducted to evaluate the sole and interactive effects of mulching(m)and poultry manure(Pm)application on soil temperature(ST),crop evapotranspiration(ETc)and water use efficiency(WUE)of *** experiment was a Randomized Complete Block Design(RCBD)with three *** trea.m.nts were m at 0 and 6t ha^(-1)and Pm at 0,10 and 20t ha^(-1).Soil temperature was measured using digital thermometer while ETc was determined by water depletion method using a Time Domain *** at field capacity was applied manually at 2-day *** appli-cation of mulch significantly lowered ST while joint application of 20t ha^(-1)Pm(Pm20)and m signifi-cantly(p≤0.05)reduced ST at 5 cm and 10 cm soil depth compared with the unmulched plots in both *** of 10t ha^(-1)Pm(Pm10)without m recorded the highest ETc(43.7 mm),while joint application of Pm20 and m reduced ETc by about 93%compared with Pm10 *** used water most efficiently when Pm20 was applied under mulched *** was 62.2%increase in WUE under mulched plots compared with the control while the residual effect of Pm10 and m significantly increased WUE by 65.5%.It was evident that m alongside application of Pm is a good strategy for regulating ST,moderating ETc and increasing okra WUE,especially during dry season fa.m.ng.

关键词： Evapotranspiration Soil temperature Volumetric water content Water depletion method Water use efficiency

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Interpolation in the Automorphism Group of a Polynomial Ring

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Algebra Colloquium 2020年第3期27卷 587-598页

作者： m'hammed El Kahoui Najoua Essamaoui mustapha Ouali Department of mathematics Faculty of Sciences Semlalia Cadi Ayyad UniversityP.O.Box 2390MarrakeshMorocco

Let R be a commutative ring with unity and SA_(n)(R)be the group of volumepreserving automorphisms of the polynomial R-algebra R^([n]).Given a proper ideal a of R,we address in this paper the question of whether the canonical group homomorphism SA_(n)(R)→SA_(n)(R/α)is *** an application,we retrieve and generalize,in a unified way,several known results on residual coordinates in polynomial rings.

关键词： polynomial automorphism coordinate residual coordinate

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Chemical Durability, Properties and Structural Approach of the Glass Series xFe₂O₃-(45-x) PbO-55P₂O₅ (with 0 ≤ x ≤ 20;mol%)

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New Journal of Glass and Ceramics 2023年第1期13卷 1-16页

作者： Radouane makhlouk Zineb Chabbou Yassine Er-rouissi m’hammed Taibi Said Aqdim Laboratory of materials Engineering for Environment and Valorization Faculty of Sciences Hassan II University Ain Chock Casablanca Morocco Physico-Chemistry Laboratory of Inorganic and Organic materials ENS University Md V Rabat Morocco mineral Chemistry Department of Chemistry Faculty of Science Hassan II University Ain Chock Casablanca Morocco

The synthesis for glasses series xFe2O3-(45-x)PbO-55P2O5, (with 0 ≤ x ≤ 20;mol%) carried out in a temperature (1050 ± 10)°C, leads to obtaining transparent glasses, brown in color and with a non-hygroscopic appearance. The study of glasses dissolution rate, immersed in distilled water at 90°C for 24 days, indicates a considerable chemical durability. The increase in the Fe2O3 content in the vitreous network to the detriment of PbO is a favorable factor for the chemical durability improvement. Different techniques have been used such as X-ray diffraction, infrared spectroscopy, DSC, SEm and density for the study of these glasses. These techniques have led to establish correlations between chemical and structural properties. Thus the results obtained confirmed the creation of P-O-m bonds (m = Pb, Fe) with a strongly covalent nature to the detriment of the hydrated P-O-P bonds and led to the formation, mainly, of pyrophosphate groups. The low melting point of Pb-O makes it possible to play an important role, at the same time, on the viscosity, on the equilibrium between the vitreous bath and the crystallites formed. The dissolution rate obtained is 100 times smaller than that of silicate glasses used as an alternative form for the vitrification of radioactive waste.

关键词： Phosphate Glasses Lead Iron Density IR DRX mEB Durabilité Chimique Vitrification Nuclear Wastes

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Occurrence and distribution of metals and porphyrins in Nigerian coal minerals

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燃料化学学报 2007年第6期35卷 641-647页

作者： OLAJIRE A A AmEEN A B ABDUL-hammed m ADEKOLA F A Department of Pure and Applied Chemistry Ladoke Akintola University of Technology Ogbomoso-Nigeria Department of Chemistry University of Ilorin Ilorin-Nigeria

The metal contents of Nigerian coal minerals were analyzed using an atomic absorption spectrophotometer. Calcium, Na, and Fe occurred as the major elements with concentrations ranging from 9 782 μg/g for Ca to 432 μg/g for Na whereas K, mg, mn, Ni, Cr, Zn, Pb, and Cu, which occurred at trace levels ranged from 673.73 μg/g for mg to 2.97 μg/g for mn. The results of the quantitative analysis of porphyrins extracted from the coal minerals showed that Onyeama coal has the highest amount of porphyrins (ca～0.96 μg/g) while Okpara has the lowest (ca～0.30 μg/g). The porphyrins were qualitatively characterized by a combination of thin layer chromatography (TLC), infrared, and ultraviolet-visible spectrophotometers. The results of the mid infrared analysis (mIR) showed the presence of absorption bands at 3 440 cm～1～3 450 cm-1 and 1 640 cm-1～1 680 cm-1 , which are owing to the stretching vibrations of N ─ H and C─ C of aromatics, with C─ H out of plane (oop) bending vibrations at wavenumbers less than 900 cm-1, all of which are characteristic absorptions of porphyrin free base. The ultraviolet-visible data showed prominent peaks at ～400 nm(Soret band) and at wavelength ranges of 535 nm～550 nm(β-band) and 565 nm～ 600 nm (α-band) for the coal porphyrins analyzed. The geochemical significance of the metals and porphyrins in coal minerals are discussed.

关键词： metals porphyrins coals TLC ultraviolet-visible and infrared spectrophotometers

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Formation of a 40 A DC Current Arc During the Opening of Silver Contacts

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Pla.m. Science and Technology 2014年第5期16卷 471-478页

作者： m'hammed ABBAOUI André LEFORT Erwann CARVOU Damien SALLAIS James Brian Alexander mITCHELL Noureddine BEN JEmAA Clermont Université Université d'AuvergneEA 3120LAEPTBP 10448F-63000 Clermont-FerrandFrance Equipe Contacts Electriques IPR(UMR CNRS 6251)Universite de Rennes 135042 Rennes CedexFrance

The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 *** experimental results show that,for arc durations shorter than 60 μs,the transfer of metal from the anode to the cathode occurs,but after passing this stage,when the two electrodes are separated by greater distances,each will display *** is the result of the diffusion of material outside the space between the two *** order to interpret these results,we have applied a classical model of the physical phenomena occurring at the root of the *** of the experimental results shows that for an arc duration of less than15 μs,no distinct cathode root is seen to exist,but beyond this,several spots appear gradually on the cathode for arc duration up to 50 μs,after which they merge into a single *** comparison between experiment results and theoretical interpretation is reasonable up to 60 μs.

关键词： arc root cathode spot anode spot erosion contacts current density

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Probabilistic Analysis of Reinforced Concrete Carbonation Depth

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materials Sciences and Applications 2013年第3期4卷 205-215页

作者： Azhar Badaoui m’hammed Badaoui Fattoum Kharchi Camp Supprt Services Integrated Paris France Ecole Nationale Supérieure des Travaux Publics Cité Sidi Garidi Kouba Algiers Algeria Université des Sciences et de la Technologie Houari Boumedienne Laboratoire Bati dans l’Environnement Algiers Algeria.

Concrete carbonation relates to the diffusion of CO2 inthe a.m.sphere through the concrete pores and to the dissolution of the hydrates. A great deal of uncertainty still remains in this subject as a result of the random nature of the infiltration of these aggressive agents as well as the material and structural properties of reinforced concrete. Consequently, in order to determine the degradation of these structures with time, it is necessary to approach the subject from a probabilistic point of view that it considers the uncertainties involved with the geometrical dimensions of these structures, with the material characteristics and with the environment and the subsequent deterioration that it provokes. The a.m.of this paper is the evaluation of carbonation depth (Xc) from a probabilistic analysis, focusing specifically on the study of the randomness of the most influential parameters on the reinforced concrete carbonation.

关键词： Carbonation Depth Lognormal Random Variable Relative Humidity Water/Cement Ratio Carbonic Gas CO2

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Carbonic Gas Randomness Effect on Reinforced Concrete Carbonation

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Engineering（科研） 2012年第1期4卷 6-10页

作者： Azhar Badaoui m’hammed Badaoui Fattoum Kharchi 不详

This paper deals the randomness effect of the pressure of carbonic gas on the carbonation phenomenon of the reinforced concrete. This analysis concentrates on the evaluation of carbonation depth (Xc) and the carbonation time (T1) which is the time necessary so that the face of carbonation arrives until the reinforcement from a probabilistic analysis. monte Carlo simulations are realized under the assumption that the carbonic gas on the surface of the concrete is random variable with a log-normal probability distribution.

关键词： Carbonation Depth Carbonation Time Lognormal Random Variable Carbonic Gas CO2 Relative Humidity Water/Cement Ratio

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Focal depth,magnitude,and frequency distribution of earthquakes along oceanic trenches

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Earthquake Science 2013年第2期26卷 75-82页

作者： O.S.hammed O.I.Popoola A.A.Adetoyinbo m.O.Awoyemi G.O.Ba.m.s O.B.Ohwo Bells University of Technology University of Ibadan Obafemi Awolowo University Afe Babalola University

The occurrence of earthquakes in oceanic tren- ches can pose a tsunami threat to lives and properties in active seismic zones. Therefore, the knowledge of focal depth, magnitude, and time distribution of earthquakes along the trenches is needed to investigate the future occurrence of earthquakes in the zones. The oceanic trenches studied, were located from the seismicity map on： latitude ＋51 ° to＋53° and longitude -160° to 176° （Aleutian Trench）, latitude ＋40° to ＋53° and longitude ＋148° to＋165° （Japan Trench）, and latitude -75° to -64° and longitude -15° to ＋30° （Peru-Chile Trench）. The following features of seis- mic events were considered： magnitude distribution, focal depth distribution, and time distribution of earthquake. The results obtained in each trench revealed that the earthquakes increased with time in all the regions. This implies that the lithospheric layer is becoming more unstable. Thus, tectonic stress accumulation is increasing with time. The rate of increase in earthquakes at the Peru-Chile Trench is higher than that of the Japan Trench and the Aleutian Trench. This implies that the convergence of lithospheric plates is higher in the Peru-Chile Trench. Deep earthquakes were observed across all the trenches. The shallow earthquakes were more prominent than intermediate and deep earthquakes in all thetrenches. The seismic events in the trenches are mostly of magnitude range 3.0-4.9. This magnitude range may indi- cate the genesis of mild to moderate tsunamis in the trench zone in near future once sufficient slip would occur with displacement of water column.

关键词： Focal depth magnitude EarthquakeOceanic trenche

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